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THE  TEXTILE  FIBERS 


WORKS  OF 
J.  MERRITT  MATTHEWS 

PUBLISHED   BY 

JOHN   WILEY   &   SONS,  Inc. 


Application   of   Dyestuffs   to   Textiles,    Paper, 
Leather  and  other  Materials 

768  pages,  6  by  9,  303  figures. 

The  Textile  Fibers 

Their  PhysicaL  MicroscopicaL  and  Chemical 
Properties.  Fourth  Edition,  Rewritten  and 
Enlarged.    1053  pages,  6  by  9,  411  figures. 


THE  TEXTILE  FIBERS 

Their  Physical,  Microscopical  and 
Chemical  Properties 


The  Late  jf^MERRITT  MATTHEWS,  Ph.D. 

Formerly  Head  of  Chemical  and  Dyeing  De  mrlment  Philadelphia 

Textile   School,   Editor   of   "Color  Trade  Journal  &   Textile 

Chemist,"  Consulting  Chemist  to  the  Textile  Industries 


FOURTH  EDITION 

Rewritten  and  Enlarged 


NEW  YORK 
JOHN   WILEY    &    SONS,    Inc. 

London:  CHAPMAN  &  HALL,  Limited 

a- 


TS 


:oPYRiGHT  1904,  11)07,  1913,  1924 

BY 

J.  Merritt  Matthews 


Copyright,  Idiil,  Rexeaed,  1931 

BY 

Augusta  G.  ^Matthews 


All  RighU  Reserved 
This  book  or  any  part  thereof  iniist  not 
be    reproduced    in    any    form    without 
the  written  permission  uf  the  publisher. 


Printed  in  U.  S.  A. 


PRESS    OF 
D/35  BRAUNWOHTH    &    CO  .    INC. 

BOOK    MANUFACTURERS 
BROOKLYN,    NEW  YORK 


PREFACE  TO  THE  FOURTH   EDITION 


Since  the  last  edition  of  this  volume  of  ten  years  ago  there  has  been 
so  much  new  matter  appearing  in  the  field  of  textile  fibers  that  the  author 
has  been  under  the  necessity  of  entirely  rewriting  and  rearranging  the 
book.  In  the  present  edition,  therefore,  the  reader  will  find  that  a  great 
deal  of  new  matter  has  been  introduced  and  the  general  plan  of  the  book 
has  been  readjusted  to  meet  the  demands  of  a  logical  development  of  the 
subject. 

The  field  of  textile  chemistry  and  the  processing  of  textile  fibers  has 
taken  on  new  proportions  during  the  past  ten  years.  To  mention  only 
one  branch  of  the  subject,  the  artificial  silk  industry,  for  example,  has 
expanded  until  at  the  present  time  more  artificial  silk  is  made  than  is 
obtained  as  a  natural  product  from  the  silkworm.  The  use  of  mercerised 
cotton  has  become  an  established  factor  in  the  cotton  industry  and  has 
become  stabilised  into  a  standard  process.  The  World  War  caused  much 
research  into  the  possibilities  of  utilising  other  fibers  than  those  normally 
employed,  and  we  find  a  great  variety  of  experimenting,  such  as  in  the 
spinning  of  the  so-called  "  staple  "  fiber  yarns.  Some  of  these  sporadic 
attempts  have  passed  out  with  the  necessity  of  their  use,  while  others  have 
shown  themselves  to  be  of  sufficient  worth  to  remain  in  the  general  body 
of  textile  products. 

The  fact  that  several  reprintings  were  called  for  in  the  third  edition 
of  this  book  has  encouraged  the  author  to  feel  that  his  attempt  to  bring 
together  such  a  large  mass  of  scientific  and  technical  data  concerning  the 
textile  fibers  has  been  more  or  less  appreciated  by  those  interested  in 
the  fiber  industries.  He  has  scoured  the  literature  of  this  country  and 
Europe  rather  thoroughly  in  the  search  for  information,  and  anything  of 
interest  or  value  he  has  not  hesitated  to  take  and  has  endeavored  to  fit 
it  in  its  proper  place  in  this  volume.  The  patent  literature  has  also  been 
thoroughly  digested,  though  it  has  been  the  author's  experience  that  in 
this  province  great  care  must  be  exercised  so  as  not  to  distort  in  one 
direction  or  the  other  the  technical  values  in  a  patent. 

Believing  that  proper  illustration  of  technical  books  is  of  extreme 
importance,  the  author  has  been  at  great  pains  to  select  from  his  own 


IV  PREFACE   TO   THE   FOURTH   EDITION 

rather  large  collection  of  fiber  micrographs  those  which  possess  some 
interest  in  relation  to  the  present  subject  matter.  Furthermore  he  has 
picked  out  wherever  he  could  find  them  fiber  micrographs  appearing  in 
the  general  technical  Hterature  and  has  endeavored  to  give  full  credit 
wherever  possible  to  the  original  source.  In  addition  to  the  fiber  micro- 
graphs endeavor  has  been  made  further  to  illustrate  the  text  with  suitable 
figures  of  apparatus  and  machinery  so  that  the  reader  may  better  visualise 
the  descriptions  of  the  processes  involved.  When  the  eye  can  see  a 
picture  the  interest  is  more  easily  aroused  and  the  attention  is  more 
readily  held,  and  the  fact  that  is  seeking  to  be  elucidated  is  more  clearly 
presented  to  the  understanding. 

The  field  of  textile  chemistry  as  a  profession  is  growing,  and  it  is  in  the 
hope  of  furthering  the  dignity  of  this  province  of  science  that  the  author 
presents  this  present  volume  to  those  whose  work  is  related  to  this  branch 
of  the  subject,  whether  in  the  scientific,  the  technical,  or  the  commercial 
aspect.  Textile  fibers  extend  into  many  lines  of  our  industrial  and  com- 
mercial activity,  and  knowing  that  the  great  majority  of  his  readers  arc 
neither  chemists  nor  scientists,  the  author  has  been  careful  to  avoid  a 
mere  scientific  presentation  of  the  subject  matter  and  has  endeavored  to 
express  himself  in  a  manner  that  is  clear  even  to  those  without  a  scientific 
education. 

J.  Merritt  Matthews. 
New  York  City,  1923. 


PREFACE  TO  THE  FIRST  EDITION 


The  present  book,  It  is  hoped,  will  be  of  assistance  to  both  the  practical 
operator  in  textiles  and  the  student  of  textile  subjects.  It  has  been  the 
outgrowth  of  a  number  of  years  of  experience  both  in  the  teaching  of  tex- 
tile chemistry  and  in  the  practical  observation  in  the  many  mill  problems 
which  have  come  under  the  notice  of  the  author  in  the  practice  of  his 
profession. 

The  textile  fibers  form  the  raw  materials  for  many  of  our  greatest 
industries,  and  hence  it  is  of  importance  that  the  facts  concerning  them 
should  be  systematised  into  some  form  of  scientific  knowledge.  The  author 
has  attempted,  however,  not  to  allow  the  purely  scientific  phase  of  the  sub- 
ject to  overbalance  the  practical  bearing  of  such  knowledge  on  the  every- 
day problems  of  industry. 

Heretofore,  the  literature  on  the  textile  fibers  has  been  chiefly  confined 
to  a  chapter  or  two  in  general  treatises  on  dyeing  or  other  textile  subjects, 
or  to  specialised  books  such  as  those  of  Hohnel,  Hanausek  and  Wiesner 
on  the  microscopy  of  the  fibers.  It  has  been  the  author's  endeavor,  in 
the  present  volume,  to  bring  together,  as  far  as  possible,  all  of  the  material 
available  for  the  study  of  the  textile  fibers.  Such  material  is  as  yet 
incomplete  and  rather  poorly  organised  at  its  best;  but  it  is  hoped  that 
this  volume  may  prove  a.  stimulus  along  the  several  lines  of  research  which 
are  available  in  this  field.  Unfortunately,  the  subject  of  the  textile  fibers 
has  been  lamentably  neglected  by  chemists,  although  there  is  abundant 
indication  that  a  fertile  field  of  research  is  open  to  them  in  this  direction, 
and  such  work  would  have  not  only  a  scientific  value,  but  would  also  be 
of  great  industrial  worth.  There  is,  as  yet,  relatively  little  known  con- 
cerning the  chemical  constituents  of  the  fibers,  and  the  manner  in  which 
the  varying  chemical  conditions  of  bleaching  and  dyeing  and  other 
chemical  treatments  affect  the  composition  and  properties  of  these  con- 
stituents. The  action  of  various  chemical  agents  on  the  fiber  as  an 
individual  has  been  but  very  imperfectly  studied.  More  work  has  been 
done  in  the  microscopical  field  concerning  the  properties  of  the  fibers; 
but  even  here  the  knowledge  is  very  incomplete  and  disjointed,  and  especial 
attention  is  drawn  to  the  fact  that  there  is  yet  a  large  amount  of  work  to 
be  done  in  the  microchemistry  of  the  subject. 


vi  PREFACE   TO   THE   FIRST   EDITION 

The  avithor  has  endeavored  to  emphasise  throughout  this  vohime  the 
importance  of  the  study  of  the  fiber  as  an  individual,  for  in  many  cases 
it  is  misleading  to  assume  that  the  behavior  of  the  individual  fiber  is 
identical  with  that  of  a  large  mass  of  fibers  in  the  form  of  yarn  or  cloth. 
In  the  latter  case,  the  difference  in  physical  condition  and  the  action  of 
mechanical  forces  have  an  important  influence.  By  going  back  to  the 
study  of  the  individual  fiber  as  a  basis,  many  explanations  can  be  given 
which  could  not  otherwise  be  discovered. 

It  is  hoped  that  this  book  may  afford  instruction  both  to  the  manu- 
facturer and  to  the  student;  assisting  the  former  in  solving  some  of  the 
many  practical  problems  constantly  occurring  in  the  manufacture  of 
textiles,  and  urging  the  latter  on  to  an  increased  effort  in  the  scientific 
development  of  the  subject. 

J.  Merritt  Matthews. 

New  York  City,  1913. 


CONTENTS 


CHAPTER  I 
GENERAL  CLASSIFICATION 

PAGE 

1 .  Fibers  Chiefly  Used  for  Textiles 1 

2.  Historical 1 

3.  Properties  Required  in  a  Textile  Fiber 3 

4.  Tensile  Strength 4 

5.  Length  of  Fiber 4 

6.  Cohesiveness 4 

7.  Pliability ;  Elasticity 5 

8.  Fineness  of  Staple 5 

9.  Uniformity  of  Staple 5 

10.  Porosity ;  Capillarity 6 

11.  Luster 6 

12.  Durabihty 6 

13.  Commercial  Availability 6 

14.  Classification  of  Fibers  by  Origin 7 

15.  Animal  and  Vegetable  Fibers 8 

16.  Vegetable  Fibers 8 

17.  Mineral  Fibers 10 

18.  Artificial  Fibers 11 

19.  Spun  Glass 11 

20.  Metallic  Threads 12 

21.  Slag  Wool 13 

22.  Artificial  Silks 14 

23.  Other  Forms  of  Artificial  Fibers 14 

24.  Fiber  Microscopy 15 

25.  Statistical 21 


CHAPTER  II 
ASBESTOS  AS  A  TEXTILE  FIBER 

1 .  Occurrence 24 

2.  Varieties  of  Asbestos 25 

3.  Grading  of  Asbestos 30 

4.  Asbestos  Yarns  and  Fabrics 32 

5.  Properties  of  Asbestos  Textiles 35 

vii 


viii  CONTENTS 


CHAPTER  III 
WOOL:    ITS  ORIGIN  AND   CLASSIFICATION 

PAGE 

1.  The  Sheep 38 

2.  Different  Classes  of  Hair  Fibers 39 

3.  Wool-bearing  Animals 40 

4.  Classification  of  Sheep 41 

5.  The  Domestic  Sheep 43 

6.  Geographical  Distribution  of  Sheep 45 

7.  Australian  Wools 46 

8.  European  Merino  Sheep 46 

9.  Sheep  of  the  United  States 48 

10.  South  American  Wools 49 

11.  African  Wools 50 

12.  Asiatic  Wools 50 

13.  Classification  of  Fibers  in  Fleece 55 

14.  Wool  Sorting 56 

15.  Character  of  Fleece 63 

16.  Commercial  Grades  of  Wool 65 

17.  Carpet  Wool 65 

18.  Statistics  of  Wool  Production 65 

CHAPTEK   IV 
PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  WOOL 

1.  Physiology  and  Structure  of  Wool 75 

2.  Morphology  of  Wool  Fiber 76 

3.  Microscopy  of  Wool 81 

4.  M  icrochemical  Reactions 89 

5.  The  Epidermal  Scales 89 

6.  Felting  Qualities 91 

7.  The  Cortical  Cells 93 

8.  Waviness  or  Curl 93 

9.  The  Medullary  Cells 96 

10.  Pigmentation  or  Color 97 

11.  Kempy  Wool 99 

12.  Pulled  Wool 100 

13.  Physical  Properties  of  Wool 101 

14.  Strength  and  Elasticity 102 

15.  Length  and  Fineness  of  Staple 106 

16.  Testing  Wool  Tops 108 

17.  Blending  of  Wool  in  Manufacture 109 

18.  Conditions  Affecting  Quality  of  Wool 112 

19.  Influence  of  Manufacturing  Operations  on  Quality  of  Wool 115 

CHAPTER  V 

THE  CHEMICAL  NATURE  AND  PROPERTIES  OF  WOOL  AND  HAIR  FIBERS 

1.  Composition  of  Raw  Wool 121 

2    Wool  Grease;  Cholesterol 122 


CONTENTS  ix 

PAGJi 

3.  Suint 123 

4.  Ash  of  Wool  Fiber 124 

5.  Coloring  Matter 125 

6.  Chemical  Constitution  of  Wool;  Keratine 126 

7.  Nitrogen  in  Wool 128 

8.  Lanuginic  Acid 128 

9.  Browning  of  W^ool 129 

10.  Sulfur  in  Wool 130 

11.  Hygroscopic  Quality 132 

12.  Water  of  Hydration  in  Wool 133 

13.  Effect  of  Moisture  on  Properties  of  Wool 134 


CHAPTER  VI 
ACTION  OF  CHEMICAL  AGENTS  ON  WOOL 

1.  Action  of  Heat 139 

2.  Reactions  with  Water  and  Steam 139 

3.  Acid  and  Basic  Nature  of  Wool 143 

4.  Action  of  Acids  on  Wool 146 

5.  Action  of  AlkaHes  on  Wool 153 

6.  Action  of  Reducing  Agents 158 

7.  Action  of  Oxidising  Agents 158 

8.  Action  of  Chlorine  on  Wool 159 

9.  Action  of  Formaldehyde  on  Wool 166 

10.  Action  of  MetalUc  Salts;  Mordants 168 

11.  Comparison  of  Various  Mordants 171 

12.  Weighting  of  Woolen  Fabrics 173 

13.  Action  of  Thiocyanates  on  Wool 174 

14.  Action  of  Zinc  Sulfate 175 

15.  Treatment  with  Radium 175 

16.  Action  of  Dyestuffs  on  Wool 176 

17.  Effect  of  Mordanting  and  Dyeing  on  Wool 178 

18.  Mildew  in  Wool « 182 


CHAPTER  VII 
RECLAIMED  WOOL  AND  SHODDY 

1 .  Recovered  Wool 183 

2.  Classification  of  Recovered  Wools 184 

3.  Shoddy 185 

4.  Mungo 186 

5.  Extract  Wool 186 

6.  The  Carbonising  Process  as  Related  to  Wool 188 

7.  Sulfuric  Acid  Process 188 

8.  Gas  Process  with  Hydrochloric  Acid 190 

9.  Use  of  Aluminium  Chloride 191 

10.  Use  of  Magnesium  Chloride 194 

11.  Comparison  of  Carbonising  Methods 195 


X  CONTENTS 

PAGE 

12.  Flocks 196 

13.  Other  Forms  of  Reclaimed  Wool 197 

14.  Economic  Aspect  of  Shoddy 198 

15.  Examination  of  Shoddy , 199 


CHAPTER  VIII 
MINOR  HAIR  FIBERS 

1.  The  Minor  Hair  Fibers 209 

2.  Mohair 209 

3.  Classification  of  Mohair 211 

4.  Microscopy  of  Mohair 215 

5.  Cashmere 216 

6.  Goat-hair 217 

7.  Alpaca 220 

8.  Vicuna  Wool 223 

9.  Llama  Fiber 225 

10.  Camel-hair 227 

11.  Cow-hair 230 

12.  Minor  Hair  Fibers 231 

13.  Fur  Fibers 235 


CHAPTER  IX 
SILK:  ITS  ORIGIN  AND  CULTIVATION 

1.  Origin  of  Silk  Fiber 242 

2.  History  of  Silk  Culture 242 

3.  The  Silkworm 244 

4.  The  Cocoon 248 

5.  The  Cocoon  Thread 249 

6.  Waste  Silk 252 

7.  Silk  Noil  and  Shoddy 255 

8.  Diseases  of  the  Silkworm 256 

9.  Wild  Silks 257 

10.  Tussah  Silk 259 

11.  Treatment  of  Wild  Silk  Cocoons 261 

12.  Spider  Silk 262 

13.  Silk  Statistics 263 


CHAPTER  X 
PHYSICAL  PROPERTIES  OF  SILK 

1 .  The  Microscopy  of  the  Silk  Fiber 270 

2.  Physical  Properties  of  Silk;  Hygroscopic  Nature 273 

3 .  Electrical  Properties 274 

4.  Luster 274 

5.  Tensile  Strength  and  Elasticity , 276 


CONTENTS  xi 

PAGE 

6.  Density 276 

7.  Scroop 277 

8.  Silk  Reeling 277 

9.  Silk  Throwing 280 

10.  Classification  of  Silk  Yarns 280 

11.  Tests  for  Classification  of  Raw  Silk 281 

CHAPTER  XI 

CHEMICAL  NATURE  AND  PROPERTIES  OF  SILK 

Chemical  Constitution 291 

Fibroine 296 

Amount  of  Fibroine  in  Raw  Silk 297 

Chemical  Properties  of  Fibroine 298 

Sericine 300 

Coloring  Matter 302 

Chemical  Reactions;  Heat 302 

Action  of  Water 302 

Action  of  Acids 303 

Action  of  Alkalies 305 

Action  of  Metallic  Salts 306 

Action  of  Dyestuffs 308 

Weighting  of  Silk 308 

Tussah  Silk 313 

Byssus  Silk 316 

CHAPTER  XII 

THE  VEGETABLE  FIBERS 

Origin  of  Vegetable  Fibers 319 

Seed-hairs  and  Bast  Fibers 320 

Dimensions  of  Fiber  Cells 323 

Classification 326 

Physical  Structure 335 

Physical  Structure  of  Bast  Fibers 337 

Microscopical  Characteristics  of  Vegetable  Fibers 338 

Physical  Properties;  Color 343 

Luster 343 

Elasticity 343 

Tensile  Strength 344 

Hygroscopic  Properties 344 

Chemical  Composition  and  Properties 347 

Lignin 349 

Chemical  Investigation  of  Vegetable  Fibers 351 

CHAPTER  XIII 
COTTON 

1.  Historical 354 

2.  Origin  and  Growth 361 


xii  CONTENTS 

paqh 

3.  Cotton  Ginning 367 

4.  Constituents  of  Cotton  Plant 368 

5.  Cotton  Linters 370 

6.  Physiology  of  Cotton  Fiber 371 

7.  Conditions  Affecting  Quality  of  Fiber 373 

8.  Botanical  Classification  of  Cotton 375 

9.  Commercial  Varieties  of  Cotton 385 

10.  Sea  Island  Cotton 386 

11.  Egyptian  Cotton 389 

12.  African  Cotton 391 

13.  Indian  Cotton 392 

14.  American  Cotton 393 

15.  Peruvian  and  Brazilian  Cottons 395 

16.  Chinese  Cotton 399 

17.  Grading  of  Cotton 399 

18.  Statistical 407 


CHAPTER  XIV 
THE  PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  COTTON 

1 .  Physical  Structure 411 

2.  Unripe  or  Dead  Fibers 411 

3.  Inner  Canal  or  Lumen  of  Fiber 413 

4.  Dimensions  of  Cotton  Fiber 414 

5.  Measurement  of  Cotton  Staple •. 416 

6.  Staple  of  Commercial  Cottons 421 

7.  Physical  Factors  for  Cotton  Fiber 431 

8.  Anatomical  Structure 433 

9.  Microscopy  of  Cotton  Fiber 439 

10.  Microchemical  Reactions 443 

11.  Physical  Properties;  Spinning  (Qualities 443 

12.  Tensile  Strength 445 

13.  Methods  of  Determining  Tensile  Strength  of  Fibers 449 

14.  Testing  Tensile  Strength  of  Yarns  and  Fabrics 453 

15.  Hygroscopic  Quality 460 

16.  Lustering  of  Cotton  Materials , . . . ,  464 


CHAPTER  XV 
CONSTITUENTS  OF  RAW  COTTON 

1.  Chemical  Constitution 467 

2.  Impurities  in  Cotton 467 

3.  Chemical  Analysis  of  Raw  Cotton 475 

4.  Coloring  Matter  in  Cotton 479 

5.  Pectin  Compounds  in  Cotton 481 

6.  Mineral  Matters  and  Ash  in  Cotton 482 

7.  Nitrogenous  Matter  in  Cotton 486 


CONTENTS  XUl 

CHAPTER  XVI 
CELLULOSE  AND  ITS  CHEMICAL  PROPERTIES 

PAGE 

1.  Cellulose 490 

2  Preparation  of  Pure  Cellulose 492 

3  Chemical  Constitution  of  Cellulose 493 

4.  Chemical  Reactions  of  Cellulose 498 

5.  Hydrocellulose 499 

6.  Hydral-cellulose 502 

7.  The  Carbonising  Process  in  Relation  to  Cotton  and  Vegetable  Fibers 502 

8  Action  of  Zinc  Chloride  on  Cellulose 503 

9  Action  of  Alkalies  on  Cellulose;  Viscose 505 

10   Esters  of  Cellulose 506 

11.  Action  of  Metallic  Salts 508 

12.  Comoound  Celluloses 508 

CHAPTER  XVII 
CHEMICAL  PROPERTIES  OF  COTTON 

1.  Action  of  Heat 510 

2.  Action  of  Light 511 

3.  Action  of  Water 511 

4.  Action  of  Cuprammonium  Solution 514 

5.  Action  of  Acids 515 

6.  Testing  Cotton  Fabrics  for  Acid 521 

7.  Action  of  Nitric  Acid 522 

8.  Action  of  Hydrofluoric  Acid 527 

9.  Action  of  Organic  Acids 527 

10.  Action  of  Tannins 531 

11.  Action  of  Dilute  Alkalies 533 

12.  Action  of  Concentrated  Solutions  of  Caustic  Alkalies 536 

13.  Action  of  Oxidising  Agents;  Oxycellulose 537 

14.  Cellulose  Peroxide 542 

15.  Action  of  Metallic  Salts 543 

16.  Weighting  of  Cotton  Yarns 548 

17.  Action  of  Coloring  Matters 550 

18.  Effect  of  Chemical  Processes  on  Cotton  Fabrics 552 

19.  Action  of  Ferments  on  Cotton 553 

20.  Action  of  Mildew  on  Cotton 554 

21.  Testing  Canvas  for  Mildew  Resistance 557 

CHAPTER  XVIII 

CHEMICAL   TREATMENT   OF  FABRICS   FOR   WATERPROOFING 

AND   FLAMEPROOFING 

1.  Waterproofing  of  Fabrics 559 

2.  Use  of  Aluminium  Acetate 560 

3.  Use  of  Fats  and  Waxes 561 

4.  Use  of  Gelatin  and  Casein 561 

5.  Waterproofing  of  Canvas 563 


xiv  CONTENTS 

PAGE 

6.  Use  of  Metallic  Soaps 563 

7.  Use  of  Paraffin 563 

8.  Waterproofing  Duplex  Fabrics 565 

9.  The  Cuprammonium  Process 565 

10.  The  Drying  Oil  Process 566 

11.  Use  of  Cellulose  Solutions 566 

12.  Electrolytic  Method  of  Waterproofing 566 

13.  Waterproofing  with  Rubber  Latex 568 

14.  Flame-proofing  of  Cotton  Fabrics 568 

15.  Perkin's  Process 568 

16.  Action  of  Various  Salts  in  Fireproofing 569 

17.  Preparation  of  Various  Fireproofing  Compounds 570 

18.  Effectiveness  of  Fireproofing  Agents 573 

CHAPTER  XIX 
MERCERISED  COTTON 

1.  Origin  of  Name ^ 578 

2.  Early  Development  of  Process 578 

3.  Essentials  of  Mercerising 580 

4.  Alkali-cellulose 581 

5.  Physical  Changes  in  Cotton  Fiber  by  Mercerising 586 

6.  Changes  in  Properties 588 

7.  Luster  of  Mercerised  Cotton 590 

8.  Effect  of  Tension 593 

9.  Effect  of  Mercerising  on  Physical  Properties  of  Yarns 594 

10.  Theory  of  Mercerising  Action 595 

11.  Conditions  of  Mercerising;  Chemicals  Employed 596 

12.  Temperature  of  Mercerising 602 

13.  Time  of  Mercerising 606 

14.  Tension  in  Mercerising 607 

15.  Washing  as  a  Process  in  Mercerising 611 

16.  Scrooping  of  Mercerised  Cotton 613 

17.  Quality  of  Fiber  for  Mercerising 615 

18.  Methods  of  Mercerising 618 

19.  Recovery  of  Caustic  Soda  from  Mercerising  Liquors 625 

20.  Properties  of  Mercerised  Cotton 629 

21.  Tests  for  Mercerised  Cotton 633 

22.  Ultramicroscopic  Appearance  of  Mercerised  Cotton 636 

23.  Cellulose  Hydrate;  Hydracellulose 637 

24.  Microscopy  of  Mercerised  Cotton 639 

25.  Lustering  bj^  Calender  Finish 640 

26.  Other  Methods  of  Lustering  Cotton 645 

27.  Crepe  Effects  by  Mercerising 646 

28.  Swiss  Finish  or  Mercerising  with  Acid 647 

CHAPTER  XX 
THE  MINOR  SEED  HAIRS 

1 .  Bombax  Cotton 655 

2.  Kapok 657 


CONTENTS  XV 

PAGE 

3.  Vegetable  Down 664 

4.  Vegetable  Silk 665 

5.  Vegetable  Wool 671 

CHAPTER  XXI 
ARTIFICIAL  SILKS 

1.  Classification 672 

2.  Collodion  or  Chardonnet  Silk 675 

3.  Lehner's  Silk 683 

4.  Other  Collodion  Silks 684 

5.  Cuprate  or  Cuprammonium  Silk 685 

6.  Viscose  Silk 696 

7.  Acetate  Silk 705 

8.  Gelatine  Silk 708 

9.  Properties  of  Artificial  Silk 709 

10.  Comparison  of  Artificial  Silks 714 

11.  Microscopy  of  Artificial  Silks 718 

12.  Ultramicroscopic  Studies  of  Artificial  Silk 720 

13.  Uses  of  Various  Cellulose  Solutions 721 

14.  Artificial  Horsehair 724 

15.  Staple  Fiber  and  Fibro 724 

16.  Ribbon  Straw  from  Artificial  Silk 725 

17.  Minor  Uses  of  Cellulose  Solutions 725 

18.  Lace  and  Tulle  from  Cellulose  Solutions 726 

19.  Animalised  Cotton 730 

20.  Statistical 731 

CHAPTER  XXII 
LINEN 

1.  The  Flax  Plant 736 

2.  The  Retting  of  Flax 741 

3.  Preparation  of  Flax  in  Belgium 744 

4.  Impurities  in  Raw  Flax 746 

5.  Microscopy  of  Linen  Fiber 748 

6.  Chemical  and  Physical  Properties 751 

7.  Chemical  Composition  of  Linen 755 

8.  Linen  Yarns  and  their  Properties 757 

9.  Absorbent  Flax 758 

CHAPTER  XXIII 
JUTE,  RAMIE  AND  HEMP 

1.  The  Jute  Plant 760 

2.  Preparation  of  Fiber 762 

3.  \'arieties  of  Jute 763 

4.  Microscopy  of  Jute 764 

5.  Chemical  Properties  of  Jute 765 


XVI  CONTENTS 

PAGE 

6.  Analysis  of  Jute 768 

7.  Uses  of  Ju1,e 770 

8.  Statistics  of  Jute 771 

9.  Lignocellulose 773 

10.  Ramie  or  China  Grass 776 

11.  Properties  of  Ramie  Fiber 779 

12.  Preparation  of  Ramie 780 

13.  Uses  of  Ramie  Fiber 785 

14.  Microscopy  of  Ramie 786 

15.  Commercial  Aspects  of  Ramie ' 789 

16.  Hemp 790 

17.  Preparation  of  Hemp 793 

18.  Microscopy  of  Hemp 794 

19    Properties  and  Uses  of  Hemp 798 

20.  Cuban  Hemp 798 

21.  Sunn  Hemp 798 

22.  Ambari  or  Gambo  n(>mp 802 

23.  New  Zealand  Flax 803 

24.  Marine  Fiber 807 

25.  Manila  Hemp 809 

chapti:r  XXIV 

MINOR  VEGETABLE  FIBERS  AND  PAPER  FIBERS 

1.  Sisal  Hemp 816 

2.  Aloe  Fiber  or  Mauritius  Hemp 819 

3.  Pita  Fiber 821 

4.  Pineapple  Fiber  or  Silk  Grass 823 

5.  Coir  Fiber 825 

6.  Istle  Fiber 828 

7.  Nettle  Fiber 830 

8.  Fiber  of  Urena  Siiuiata 833 

9.  Sansevieria  Fil)ers 833 

10.  Tillandsia  Fiber 834 

11.  Solidonia  Fiber 836 

12.  Fiber  of  Sea  Grass 836 

13.  Raphia 837 

14.  Bromelia  Fibers 838 

15.  Piassava 840 

16.  Paper  Mulberry  Fiber 842 

17.  Perini  Fiber 843 

18.  Couratari  Fiber 844 

19.  Peat  Fiber 844 

20.  Textile  Yarns  from  Wood-pulp 845 

21.  Paper  Fibers  and  their  Examination 850 

CHAPTER  XXV 
GENERAL  ANALYSIS  OF  THE  TEXTILE  FIBERS 

1.  General  Classification 864 

2.  Microscopical  Investigation 865 


CONTENTS  xvii 

PAGE 

3.  Qualitative  Chemical  and  Microchemical  Tests 866 

4.  Reagents  for  Testing  Fibers 866 

5.  Ruthenium  Red  as  a  Reagent  for  Testing  Textile  Fibers 873 

6.  General  Tests  for  Vegetable  Fibers 875 

7.  Distinction  between  Animal  and  Vegetable  Fibers 876 

8.  Analytical  Reactions  of  Vegetable  Fibers 880 

9.  Micro-analytical  Tables  for  Vegetable  Fibers 883 

10.  Reactions  of  Bast  Fibers 897 

11.  Microscopical  Comparison  of  Various  Fibers 897 

12.  Systematic  Analysis  of  Mixed  Fibers 897 

13.  Reactions  of  Vegetable  Fibers  with  lodine-Sulfuric  Acid  Reagent , , ,  903 


CHAPTER  XXVI 
ANALYSIS  OF  TEXTILE  FABRICS  AND  YARNS 

1.  Wool  and  Cotton  Fabrics 905 

2.  Analysis  of  Wool  and  Staple  Fiber  Mixtures 911 

3.  Wool  and  SUk 912 

4.  SUk  and  Cotton 913 

5.  Wool,  Cotton  and  Silk 914 

6.  Distinction  between  Cotton  and  Linen 920 

7.  Distinction  between  New  Zealand  Flax,  Jute,  Hemp  and  Linen 925 

8.  Distinction  between  Linen  and  Hemp 925 

9.  Distinction  between  Manila  Hemp  and  Sisal 929 

10.  Testing  for  Lignin 931 

11.  Detection  of  Cotton  in  Kapok 932 

12.  Identification  of  Artificial  Silks 933 

13.  Distinction  between  True  Silk  and  Different  Varieties  of  Wild  Silk 937 

14.  Wild  Silks  of  Minor  Importance 940 

15.  Appearance  of  Silks  under  Polariscope , 941 


CHAPTER  XXVII 
TESTING  OF  TEXTILE  FABRICS 

1.  Conditioning  of  Textiles 943 

2.  Apparatus  for  Conditioning 949 

3.  Calculations  Involved  in  Conditioning 951 

4.  Analysis  of  Weighting  in  Silk  Fabrics 960 

5.  Calculations  in  Silk  Weighting 971 

6.  Oil  and  Grease  in  Yarns  and  Fabrics 975 

7.  Estunation  of  Finishing  Materials  on  Fabrics 978 

8.  Analysis  of  Bleached  Cotton 980 

9.  Testing  Waterproof  Fabrics 986 

10.  Testing  the  LiabiUty  of  Waterproofed  Fabrics  to  Spontaneous  Combustion. . .  992 

11.  Testing  Waterproofed  Fabrics  for  the  Effect  of  Extremes  of  Climate 993 

12.  Testing  the  DurabiUty  of  Fabrics 994 

13.  Testing  Permeability  of  Balloon  Fabrics 994 

14.  Testing  Heat-retaining  Value  of  Fabrics 994 


xviil  CONTENTS 

CHAPTER  XXVIII 
ANALYSIS  OF  FIBERS  AND  YARNS  IN  FABRICS 


PAGE 


1.  Microscopic  Analysis  of  Fabrics 996 

2.  Analysis  of  Yarns  in  Cloth 998 

3.  Determination  of  the  Size  of  Yarns 998 

4.  Size  of  Cotton  Y'arns 1001 

5.  Woolen  Yarns 1004 

6.  Worsted  Yarns 1005 

7.  Silk  Yarns lOOG 

8.  Artificial  Silk  Y'arns 1016 

9.  Linen,  Jute,  etc 1018 

10.  Comparison  of  Yarn  Sizes 1019 

Bibliography 1021 


THE  TEXTILE  FIBERS 


CHAPTER  I 
GENERAL  CLASSIFICATION 

1.  Fibers  Chiefly  Used  for  Textiles. — In  order  to  be  serviceable  in 
a  textile  fabric,  a  fiber  must  possess  sufficient  length  to  be  woven  and  a 
physical  structure  which  will  permit  of  several  fibers  being  spun  together, 
thereby  yielding  a  continuous  thread  of  considerable  tensile  strength  and 
pliability.  Although  there  are  several  fibers,  such  as  spun  glass,  asbestos, 
various  grasses,  etc.,  which  are  used  for  the  manufacture  of  textiles  in 
peculiar  and  rare  instances,  yet  the  fibers  which  are  employed  to  the 
greatest  extent  and  which  exhibit  the  most  satisfactory  qualities  are  wool, 
silk,  cotton,  and  linen.  All  of  these  possess  an  organised  structure,  and 
are  the  products  of  a  natural  growth  in  life  processes. 

2.  Historical. — The  study  of  the  various  textile  fibers  employed  by 
different  nations  throughout  the  ages  is  an  excellent  commentary  on  the 
progress  of  civilisation  and  affords  a  good  idea  of  the  industrial  life  and 
economic  condition  of  the  peoples  concerned.  It  is  an  interesting  fact 
that  most  of  the  commercial  fibers  that  are  in  use  at  the  present  time 
were  also  prominent  in  the  industrial  life  of  past  ages.  Cotton,  flax  and 
hemp  were  apparently  known  and  utilised  in  past  ages  in  much  the  same 
manner  as  they  are  to-day,  and  we  find  them  well  distributed  among 
the  various  nations  of  the  world.  The  animal  fibers  of  wool  and  various 
hairs  were  also  utilised  for  the  making  of  fabrics  and  other  materials 
in  the  earliest  ages.  Silk  seems  to  have  been  more  recently  recognised 
and  to  have  been  developed  for  a  long  period  in  one  nation  exclusively, 
namely,  China.  The  use  of  flax  or  linen  perhaps  dates  back  to  a  greater 
antiquity  than  that  of  any  other  fiber,  or  at  least  it  is  the  fiber  of  which 
we  possess  the  most  ancient  records.  The  cultivation  of  flax  and  the 
utilisation  of  its  fiber  goes  back  to  the  Stone  Age  of  Europe.  Remnants 
of  flax  fabrics  have  been  found  in  the  remains  of  the  Swiss  Lake  Dwellers, 
who  were  apparently  a  people  contemporaneous  with  the  mammoth  in 
Europe.     Well-authenticated  specimens  of  these  fabrics  are  to  be  found 


2  GENERAL  CLASSIFICATION 

in  our  present  museums.  Four  or  five  thousand  years  later  the  Egyptians 
are  known  to  have  cultivated  flax  also,  and  in  fact  the  species  of  plant 
so  utilised  appears  to  be  almost  identical  with  the  common  flax  plant  of 
the  present  day. 

The  culture  and  manufacture  of  flax  as  well  as  the  spinning  and 
weaving  of  the  yarn  is  shown  in  the  pictorial  carvings  on  the  walls  of 
Egyptian  palaces,  temples  and  tombs.  Also  linen  fabrics  probably  4500 
years  old  have  been  found  in  Egyptian  tombs,  employed  as  mummy 
cloths,  and  these  fabrics  show  a  wide  variety  of  structures,  from  very 
fine  delicate  cloth  to  coarse  sail  cloth  or  canvas.  As  much  as  300  yds. 
of  cloth  was  used  to  wrap  one  mummy;  consequently  these  mummy 
cloths,  which  are  still  in  a  fine  state  of  preservation,  have  been  handed 
down  to  us  in  considerable  quantity  and  may  be  seen  in  almost  any 
museum.  Much  of  the  cloth  was  evidently  undyed,  but  a  considerable 
part  was  colored,  chiefly  in  red,  yellow  and  purple. 

From  the  historical  records  of  the  Babylonians  it  is  also  apparent 
that  their  textile  industries  were  in  a  high  state  of  development  and  they 
were  well  acquainted  with  the  use  of  flax,  cotton  and  wool.  The  early 
Greeks  were  evidently  more  familiar  with  wool  as  a  textile  than  with 
either  linen  or  cotton,  though  later  these  were  brought  in  from  other 
countries.     The  same  is  also  true  of  the  early  Romans. 

In  ancient  America,  flax  and  hemp  were  both  known  to  the  Aztecs  of 
Mexico,  and  cotton  was  also  known  to  tiie  ancient  Incas  of  South  America. 
In  ancient  India,  cotton  seems  to  have  been  the  national  textile  fiber, 
and  the  expert  use  of  this  fiber  in  the  weaving  of  fine  and  delicate  fabrics 
became  famous,  if  we  can  believe  the  extreme  praise  of  them  to  be  met 
with  in  poetry  and  legend.  The  Hindoo  muslins  were  said  to  be  so  fine 
that  when  laid  on  the  grass  and  wet  with  the  dew  they  became  invisible. 
It  is  not  possible  for  us  to  say  just  how  far  back  in  history  the  use  of 
cotton  was  first  known  in  India,  but  we  have  records  of  800  B.C.,  which 
indicate  that  the  cotton  industry  at  that  time  was  well  known  and 
long  established.  Cotton  was  not  introduced  into  Greece  until  about 
200  B.C. 

The  use  of  hemp  among  the  ancients  was  apparently  very  limited; 
the  hemp  plant  grows  wild  throughout  India,  but  it  was  regarded  more 
as  a  source  of  a  drug  (hasheesh)  than  as  a  fiber  plant.  We  find  no  mention 
of  hemp  in  the  Bible,  and  it  is  very  seldom  referred  to  by  other  writers 
of  antiquity.  In  the  Sanskrit  Institutes  of  Menu,  however,  we  find 
mention  of  sana  as  a  fiber  from  which  certain  sacrificial  threads  were 
prepared.  This  sana  has  been  supposed  to  refer  to  Sunn  Hemp,  which 
is  one  of  the  commercial  fibers  even  of  the  present  time  in  India.  Hemp 
was  used  by  the  Scythians  in  500  B.C.  for  cordage,  and  apparently  it 
was  also  known  to  the  Chinese  at  a  very  early  period. 


PROPERTIES   REQUIRED   IN   A  TEXTILE  FIBER  3 

One  of  the  oldest  fibers  of  Oriental  nations  was  China  grass  or  ramie. 
The  utilisation  of  this  fiber  antedates  the  written  records  of  history  both 
in  China  and  in  India,  and  it  may  have  been  used  in  Egypt  for  mummy 
cloth  contemporaneous  with  flax.  This  fiber  was  not  known  to  the 
ancient  Americans,  but  these  people  used  the  fiber  from  the  agave  (sisal 
hemp  or  henequen)  for  the  making  of  cordage.^ 

3.  Properties  Required  in  a  Textile  Fiber. — The  availability  of  a 
fiber  for  textile  purposes  must  be  considered  with  reference  to  its  adapta- 
tion to  the  various  operations  and  processes  through  which  it  is  required 
to  pass  in  the  formation  of  a  woven  fabric.  Preliminary  to  the  operation 
of  weaving  (or  other  similar  operation  by  which  a  fabric  is  made)  it  is  neces- 

1  It  is  impossible  to  state  what  was  the  first  fiber  employed  for  textile  purposes, 
and  how  it  came  to  be  used.  Weaving  seems  to  have  existed  long  before  writing; 
consequently  it  is  hopeless  to  expect  any  historical  record  of  the  origins  of  textile  fibers. 
Probably  the  use  of  fibers  in  weaving  developed  out  of  the  ancient  art  of  basket  making. 
Many  primitive  races  early  discovered  that  the  stems  of  plants  could  be  twisted 
together  to  form  a  framework  which  could  be  used  for  many  purposes,  such  as  stockades 
to  protect  them  from  wild  animals  and  enemies,  rush  huts  to  protect  them  from  the 
inclemencies  of  the  weather,  baskets  to  hold  and  carry  food,  and  various  other  materials. 
It  may  have  been  that  through  wear  and  the  action  of  the  weather  a  basket  made  from 
flax  stems  changed  its  nature  and  became  a  bag.  The  thoughtful  savage,  no  doubt, 
discovered  that  by  weathering  the  flax  straw  long  lustrous  fibers  could  be  obtained, 
which  could  then  be  twisted  together  to  form  a  thread  or  cord,  and  this  could  be  inter- 
laced to  form  a  new  material,  cloth.  Flax  seems  to  be  found  in  all  remains  of  pre- 
historic people,  and  it  is  very  likely  that  this  was  man's  first  textile  fiber.  Wool  would 
probably  be  the  next  textile  fiber  that  came  into  use,  as  primitive  man  long  employed 
sheep  skins  as  a  garment,  and  it  would  be  natm-al  to  expect  that  he  would  soon  become 
aware  of  the  possibiUties  of  using  the  fiber  independent  of  the  skin.  In  the  Middle 
Ages  wool  became  the  staple  industry  of  England,  and  its  importance  is  handed  do^vn 
in  the  legend  of  the  "woolsack"  in  Parliament.  It  seems  that  Edward  III  did  not 
wish  his  Parliament  to  forget  that  the  country's  prosperity  depended  on  its  commerce, 
of  which  wool  was  then  the  principal  item,  so  he  ordered  that  sacks  of  wool  should 
be  placed  in  the  House  of  Lords.  A  Lord  Chancellor  evidently  found  that  these 
sacks  were  comfortable  to  sit  on,  and  in  time  the  "woolsack"  became  the  recognised 
seat  of  this  official. 

It  is  probable  that  cotton  did  not  come  into  use  as  a  textile  fiber  until  long  after 
both  flax  and  wool.  It  was  evidently  first  used  in  India  thousands  of  years  ago.  Its 
introduction  into  European  trade  is  of  comparatively  recent  date,  it  being  first 
imported  and  spun  into  yarn  in  the  early  part  of  the  eighteenth  century.  At  first 
it  was  used  only  as  a  filling  yarn  with  a  linen  warp,  and  it  was  not  until  1783  that  the 
first  all-cotton  cloth  was  made  in  Lancashire. 

The  use  of  silk  was  discovered  in  historic  times,  being  used  at  a  very  early  period 
in  Asia,  and  only  came  into  Europe  in  the  Middle  Ages.  At  first  it  was  used  only  as 
embroidery  and  decorative  material,  but  ultimately  was  used  for  weaving. 

During  the  World  War  the  Germans  fell  back  on  the  use  of  paper  for  the  making 
of  textile  yarns.  This,  however,  was  not  a  very  new  invention,  as  paper  yarns  have  long 
been  used  by  the  Japanese,  and  it  is  also  probable  that  something  similar  was  employed 
by  the  ancients.  Wires  of  metal  have  also  been  used  for  weaving;  threads  of  gold 
and  silver  having  long  been  employed  as  decorative  material  in  the  weaving  of  cloth. 


4  GENERAL  CLASSIFICATION 

sary  that  a  continuous  thread  or  yarn  be  prepared  from  the  fiber  and  for 
the  manufacture  of  such  a  yarn  certain  quaUties  are  necessary  and  certain 
others  are  desirable. 

4.  Tensile  Strength. — Probably  the  most  important  quality  is  tensile 
strength,  for  if  the  individual  fiber  does  not  possess  in  itself  considerable 
strength  it  will  not  be  possible  to  make  from  it  a  yarn  suitable  for  use  in 
the  arts.  There  are  a  number  of  fibers,  especially  among  the  vegetable 
class  (such  as  those  of  the  common  milkweed,  etc.),  which  might  prove  of 
considerable  value  but  for  their  lack  of  sufficient  tensile  strength.  The 
four  fibers  mentioned  in  a  preceding  paragraph  as  the  most  important 
are  all  characterised  by  a  high  tensile  strength.  Although  dependent 
also  on  other  qualities,  the  resistance  of  a  fiber  to  use  and  wear  is  primarily 
dependent  on  its  tensile  strength. 

5.  Length  of  Fiber. — The  second  important  quality  which  determines 
the  usefulness  of  a  textile  fiber  is  its  length.  It  is,  of  course,  very  easy 
to  understand  even  without  resort  to  technical  explanations,  that  where 
a  continuous  thread  is  to  be  made  up  of  a  large  number  of  individual 
elements,  these  elements  must  possess  a  considerable  length  with  reference 
to  their  thickness,  otherwise  it  would  not  be  possible  to  make  a  thread 
that  would  hold  together.  In  a  general  way  and  other  conditions  being 
equal,  the  strength  of  such  a  thread  will  be  directly  proportional  to  the 
length  of  the  individual  fiber  elements  employed.  On  this  account  a 
yarn  composed  of  the  long  fibers  of  Sea  Island  cotton  is  much  stronger 
than  a  similar  yarn  prepared  from  the  relatively  short  fibers  of  upland 
cotton.  The  lowest  economic  limit  in  length  for  fibers  to  be  employed 
for  purposes  of  spinning  is  about  5  mm.  Fibers  of  less  length  than  this, 
however,  are  available  for  paper  making.  During  the  recent  war,  when 
suitable  fibers  were  not  available  in  Germany,  processes  were  developed 
for  the  spinning  of  very  short  staples  from  waste  and  reworked  materials. 

6.  Cohesiveness. — A  third  essential  quality  for  a  textile  fiber  is  cohe- 
siveness.  By  this  is  meant  the  property  of  the  individual  fibers  cohering 
or  holding  on  to  one  another  when  spun  into  a  yarn.  This  is  usually 
brought  about  by  the  surface  of  the  fibers  possessing  a  high  degree  of 
frictional  resistance.  The  surface  of  wool,  for  instance,  is  quite  rough 
and  serrated  by  reason  of  the  projecting  edges  of  its  epidermal  scales,  the 
same  as  the  surface  of  a  fish.  These  projections  easily  catch  in  one  another, 
so  that  when  several  wool  fibers  are  twisted  together  they  offer  con- 
siderable frictional  resistance  to  being  pulled  apart.  Cotton  also  possesses 
an  irregular  surface  which  manifests  a  high  degree  of  friction  and  this  is 
greatly  accentuated  by  the  occurrence  of  many  twists  in  the  fiber  which 
interlock  when  several  fibers  are  spun  together,  and  thus  prevent  the 
elements  of  the  yarn  from  slipping  apart  when  subjected  to  strain.  Linen 
(and  other  analogous  vegetable  fibers)  has  also  a  roughened  surface,  and 


PLIABILITY;  ELASTICITY  5 

furthermore  possesses  knot-like  formations  throughout  its  length  which, 
of  course,  greatly  enhance  the  surface  friction  of  the  fiber.  Silk,  on  the 
other  hand,  when  considered  as  the  purified  fiber,  has  a  comparatively 
smooth  surface,  and  its  cohesiveness  when  employed  as  a  spun  fiber,  as . 
in  the  case  of  waste  silk,  is  chiefly  due  to  its  great  length  in  proportion 
to  its  thickness  which  allows  of  the  fiber  elements  of  the  yarn  wrapping 
around  one  another  a  great  number  of  times,  giving  rise  in  this  manner 
to  great  frictional  resistance.  When  silk  is  not  employed  as  a  spun  fiber 
as  in  the  case  of  thrown  silk  yarns,  the  individual  elements  of  the  yarn 
must  be  considered  as  practically  continuous  filaments.  The  lack  of 
cohesiveness  in  many  minor  vegetable  fibers,  such  as  ramie  and  the 
several  varieties  of  so-called  vegetable  silks,  greatly  reduces  their  other- 
wise practical  value  as  spinning  fibers.  The  latter  fibers  more  especially 
possess  very  smooth  surfaces,  and  consequently  they  slip  over  one  another 
in  a  yarn  and  are  easily  pulled  apart. 

7.  Pliability;  Elasticity. — Another  quality  which  is  very  essential  to  a 
satisfactory  textile  fiber  is  pliability,  which  permits  of  one  fiber  being  easily 
wrapped  around  another  in  the  spinning  operation.  The  stiffer  and  more 
wiry  the  nature  of  a  fiber,  the  less  is  it  adapted  to  the  purposes  of  textile 
use.  The  fibers  of  ordinary  wool,  for  instance,  are  very  pliable,  and  are 
employed  in  the  production  of  a  wide  variety  of  fabrics  for  which  a  stiff 
wiry  fiber,  such  as  horsehair,  would  be  entirely  unsuitable.  The  pliability 
of  a  fiber  also  determines  in  great  measure  its  elasticity  and  resiliency, 
qualities  which  are  often  of  prime  importance  in  the  manufacture  of 
textile  fabrics.  Lack  of  these  properties  will  make  the  fiber  and  its  result- 
ing products  brittle  and  unyielding,  and  hence  greatly  limit  the  field  of  its 
usefulness.  Fibers  of  glass,  for  instance,  however  fine  they  may  be 
prepared,  have  a  very  narrow  range  of  utility. 

8.  Fineness  of  Staple.— Furthermore,  a  fiber  must  possess  sufficient 
fineness  of  staple  to  be  useful  in  the  production  of  spun  yarns.  The 
principal  fibers  all  have  very  small  diameters  and  a  large  number  of  them 
can  be  twisted  together  to  yield  a  fine  thread.  Other  things  being  equal, 
the  finer  the  staple  of  the  fiber,  the  finer  the  yarn  which  can  be  produced 
from  it.  The  coarse  vegetable  fibers,  such  as  jute,  hemp,  sisal,  etc.,  can 
only  be  used  for  textile  purposes  in  the  production  of  crude,  low-grade 
fabrics ;  the  chief  uses  of  such  fibers  being  for  the  manufacture  of  bagging, 
cordage,  etc. 

9.  Uniformity  of  Staple. — Besides  these  more  properly  termed  essential 
qualities,  there  are  a  number  of  others  which  more  or  less  determine  the 
value  of  a  fiber  for  textile  purposes.  Uniformity  of  staple  is  a  valuable 
property;  by  this  is  meant  evenness  in  the  length  and  diameter  of  the 
individual  fibers.  This  enhances  the  spinning  quality  very  much  and 
aids  in  the  production  of  an  even  thread.     If  in  one  variety  of  cotton,  for 


6  GENERAL  CLASSIFICATION 

instance,  the  individual  fibers  vary  widely  in  their  length  and  diameter, 
its  value  will  be  much  less  than  another  variety  in  which  these  dimen- 
sions are  more  uniform.  As  both  wool  and  cotton  in  their  natural  state 
show  considerable  variation  in  the  size  of  the  individual  fibers,  in  order  to 
heighten  the  quality  of  the  yarns  produced  a  process  known  as  "combing" 
is  utilised,  whereby  the  longer  fibers  are  separated  from  the  shorter  ones, 
and  hence  much  greater  uniformity  in  staple  is  obtained.  The  more 
uniform  the  length  of  the  fibers,  the  more  even,  and  hence  stronger,  will 
be  the  resulting  yarn. 

10.  Porosity ;  Capillarity. — Another  desirable  quality  for  a  textile  fiber 
to  possess  is  that  of  porosity  or  capillarity.  By  this  is  meant  that  the 
fiber  should  be  capable  of  easily  absorbing  liquids  and  solutions  and  of 
permitting  these  thoroughly  to  permeate  its  substance.^  This  property 
is  important  as  it  allows  of  the  dyeing,  bleaching,  and  otherwise  pre- 
paring the  fibers  by  modifying  their  natural  condition.  Fibers  that  could 
not  be  dyed  or  bleached  would  have  but  a  hmited  application  in  the  manu- 
facture of  textiles. 

11.  Luster. — A  further  quality,  which  under  certain  conditions 
enhances  the  value  of  a  textile  fiber,  is  luster.  Fibers  possessing  this 
quality  to  a  marked  degree,  such  as  silk,  mercerized  cotton,  and  certain 
kinds  of  wool,  are  capable  of  producing  a  wide  variety  of  beautiful  effects. 
Luster,  however,  is  not  an  essential  quality  in  a  fiber  as  regards  usefulness; 
it  is  only  an  ornamental  quality  which  adds  to  the  beauty  of  the  product. 

12.  Durability. — There  are  two  other  features  which  must  also  be 
considered  with  reference  to  the  textile  fibers  as  well  as  to  any  other  manu- 
factured article.  The  first  of  these  is  durability,  by  which  is  meant  that 
the  substance  of  which  the  fiber  is  composed  must  possess  a  degree  of 
permanence  which  permits  of  its  general  use;  it  must  be  capable  of  with- 
standing the  conditions  of  wear  to  which  it  may  be  reasonably  subjected. 
The  use  of  artificial  silk  (lustra-cellulose),  for  instance,  is  greatly  limited 
by  reason  of  the  fact  that  this  fiber  becomes  much  weakened  and  is  liable 
to  undergo  disintegration  when  moistened  with  water.  The  principal 
textile  fibers  are  all  very  resistant  to  the  ordinary  conditions  of  wear,  more 
so,  in  fact,  than  many  of  the  raw  materials  used  in  the  preparation  of 
most  manufactured  articles. 

13.  Commercial  Availability. — The  second  feature  to  which  reference 
is  made  has  principally  an  economic  significance.  In  order  to  possess 
commercial  value  a  fiber  must  be  available  in  large  quantity,  and  its  supply 
must  be  more  or  less  constant  and  readily  marketed;  it  furthermore  must 

1  Gaidukov  {Zeii.  Farb.  Ind.,  1908,  p.  251)  has  made  an  extensive  study  of  various 
textile  fibers  by  ultramioroscopic  methods  and  has  confirmed  the  opinion  that  the 
fibers  are  of  a  colloidal  character.  The  ultramicrophotographs  published  by  Zeiss  & 
Co.,  in  connection  with  this  research,  are  very  instructive  and  interesting. 


CLASSIFICATION  OF  FIBERS   BY  ORIGIN  7 

be  cheap.  It  is  possible  to  use  spider's  silk,  for  example,  as  a  textile  fiber 
for  certain  purposes,  but  the  supply  of  this  material  is  small  and  uncertain, 
and  there  are  many  difficulties  in  the  way  of  its  production  which  would 
doubtless  prevent  it  ever  becoming  a  staple  article  of  commerce.  There 
are  a  large  number  of  vegetable  fibers  which  examination  shows  to  possess 
many  valuable  properties  for  textile  purposes,  but  the  practical  supply 
of  which  is  so  uncertain  as  to  render  them  unworthy  of  commercial 
consideration. 

14.  Classification  of  Fibers  by  Origin. — Though  textile  fibers  in  general 
consist  of  a  wide  range  of  materials,  for  convenience  in  study  they  may  be 


Fig.  1. — Wool  Fiber  Emerging  from  Skin  Tissue. 


divided  into  four  distinct  classes,  as  follows:  (a)  animal  fibers,  (6)  vege- 
table fibers,  (c)  mineral  fibers,  (d)  artificial  fibers.  According  to  a  very 
complete  compilation  of  M.  Bernardin  in  his  Nomenclature  uselle  des  fibers 
textiles,  the  number  of  plant  fibers  used  by  the  human  species  is  more  than 
550  and  perhaps  about  700.  Calculating  in  addition  thereto  the  mineral 
fibers  (asbestos  and  kindred  substances)  as  well  as  the  various  packing 
materials,  spun  fibers,  brush  materials,  and  animal  hairs,  and  silk,  the 
number  of  single  substances  would  probably  amount  to  1000,  if  not  more. 


8 


GENERAL  CLASSIFICATION 


These  raw  materials  can  occur  in  different  forms,  and  many  of  them  are 
important.  Sheep's  wool,  for  instance,  is  known  in  as  many  as  50  different 
varieties.  It  is  clear  that  the  various  characteristics  of  all  these  forms 
would  be  very  difficult  to  delineate  and  to  differentiate  from  each  other. 
The  solution  of  such  numerous  questions  as  would  be  raised  by  the  com- 
parative investigation  of  so  many  objects  would  necessitate  the  accumu- 
lation of  a  large  mass  of  unimportant  details  and  divert  the  attention 
of  the  observer  from  the  main  points.  In  fact  most  of  the  exotic  fibers 
are  unimportant  or  are  only  employed  in  the  localities  in  which  they 
are  grown. 

15.  Animal  and  Vegetable  Fibers. — According  to  their  origin,  we  may 
divide  the  principal  fibers  into  two  general  classes,  those  derived  from 
animal  and  those  derived  from  vegetable  life.  The  former  includes  wool 
and  silk,  and  the  latter  cotton  and  linen. 

Animal  fibers  are  essentially  nitrogenous  substances  (protein  matter), 
and  in  some  cases  contain  sulfur.  Protein  matter  is  of  the  character  of 
albumen,  and  forms  one  of  the  principal  ingredients  of  animal  tissues. 
It  is  essentially  nitrogenous  in  composition  and  is  especially  characterised 
by  the  peculiar  empyreumatic  odor  evolved  when  it  is  burned.  One  of  the 
readiest  and  most  conclusive  tests,  in  fact,  which  may  be  used  to  distinguish 
between  an  animal  and  a  vegetable  fiber  is  to  notice  the  odor  evolved  on 
burning  in  the  air.  With  regard  to  their  physical  condition,  it  may  be 
said  that  the  proteids  composing  the  animal  fibers  are 
essentially  of  a  colloidal  nature;  that  is,  they  resemble  a 
solidified  jelly  in  condition.  This  property  of  the  fibers 
may  be  used,  to  a  great  extent,  to  explain  their  action  with 
solutions  of  dyestuffs  and  metallic  salts,  in  which  the  theory 
of  solid  solution,  adsorption,  and  osmosis  comes  into  play. 
Alkalies  readily  attack  the  animal  fibers,  causing  them  to 
be  dissolved,  but  they  withstand  the  action  of  mineral 
acids  to  a  considerable  degree.  Contrary  to  the  vege- 
table fibers,  they  are  readily  injured  if  exposed  to  elevated 
temperatures. 

16.  Vegetable  Fibers. — These   consist    of    plant   cells 

usually   rather   simple  in  structure  and  forming  an  integral 

part  of  the  plant  itself.     Plant  cells  are  of  different  character 

and  size  depending  on  the  part  of  the  plant  in  which  they 

Fig.  2. — Cells  of  occur  and  the  office  or  function  they  perform  in  the  develop- 

Wood  Tissue,     ment  of  the  plant  tissue.     These  cells  consist  of  tubes  gener- 

(X500.)         ally  between  0.001  in.  and  0.002  in.  in  diameter;   their  ends 

are  usually  pointed  and  in  their  arrangement  overlap  one 

another.     (See  Fig.  2.)     In  the  fibrous  layers  occurring  in  plants  these 

cells  are  sufficiently  long  and  so  interlaced  as  to  give  a  fiber  of  considerable 


VEGETABLE   FIBERS 


9 


strength,  whereas  in  plain  woody  tissue  the  cells  are  short  and  properly 
speaking  yield  no  fiber  of  sufficient  strength  or  length  to  be  used  for  textile 
purposes.  In  monocotyle- 
dons, according  to  Dr.  Morris, 
the  fibrous  cells  are  found 
built  up  with  vessels  into  a 
composite  structure  known  as 
fibro vascular  bundles;  these 
bundles  occur  in  the  leaves 
and  stems,  but  not  in  the 
outer  bark  of  plants  (see 
Fig.  3),  and  are  usually  found 
imbedded  in  a  soft  cellular 
tissue  known  as  parenchyma. 
The  vegetable  fibers  are  cap- 
able of  withstanding  rather 
high  temperatures,  and  are 
not  weakened  or  disintegrat- 
ed by  the  action  of  dilute 
alkalies.  They  consist  essen- 
tially of  cellulose,  which  may 
be  in  a  very  pure  form  or 
be  mixed  with  its  various 
alteration  products.    In  some 

cases  the  fiber  consists  of  some  cellulose  derivative  obtained  by 
chemical  means,  such,  for  instance,  as  mercerised  cotton.  Concentrated 
alkalies  produce  alteration  products  with  the  vegetable  fibers.  Free 
sulfuric  or  hydrochloric  acid,  even  if  only  moderately  strong,  will  quickly 
attack  the  fiber,  disintegrating  its  organic  structure  and  forming  hydrolysed 
products.  Nitric  acid,  on  the  other  hand,  forms  nitrated  celluloses  (the 
so-called  nitro-celluloses)  and  various  oxidation  derivatives. 

It  is  generally  considered  that  the  animal  fibers  have  a  lower  conduc- 
tivity for  heat  than  have  the  vegetable  fibers,  and  in  consequence  fabrics 
made  from  wool  and  silk  are  warmer  than  those  made  from  cotton  and  linen. 
From  actual  tests,  however,  it  would  seem  that  this  quality  was  due  more 
to  the  structure  of  the  fabric  than  to  the  character  of  the  fiber. 

According  to  Dietz  the  specific  heats  of  the  various  fibers  are  as 
follows : 

Raw  silk 0.331 

Boiled-off  silk 0.331 

Worsted  yarn 0. 326 

Artificial  silk 0 .  324 

Linen 0.321 

Cotton    0.319 


Fig.  3. — Section  of  Fibrous  Plant  Cells  (Sisal 
Hemp).  (X300.)  Par.,  cellular  parenchyma; 
S.S.,  starch  layer;  Scl.,  sclerenchyma;  M.L., 
middle  lamella;  B.S.,  bundle  sheath;  X,  xylem 
or  wood  cells;  PH.,  phloem  or  bast  cells.  (After 
Morris.) 


10  GENERAL    CLASSIFICATION 

Jute 0.324 

Kapok 0.324 

Hemp 0. 323 

Manila  hemp 0.322 

Sisal  hemp 0.317 

Asbestos 0. 251 

Glass  wool 0 .  157 

Straw 0.325 

Soda  wood  pulp 0 .  323 

Sulfite  wood  pulp 0 .  319 

Count  Rumford  made  some  interesting  experiments  relative  to  the 
"  heat-retaining  value  "  of  various  clothing  materials.  He  heated  a 
large  thermometer  to  a  given  temperature  and  then  ascertained  the 
length  of  time  required  for  the  thermometer  to  fall  to  a  given  point  when 
surrounded  with  the  various  materials  experimented  upon.  The  times 
taken  by  the  thermometer  in  falling  from  70°  to  10°  Reaumur,  when 
surrounded  with  various  substances,  were  as  follows: 

Seconds. 

Air 576 

Raw  sUk 1284 

Sheep's  wool 118 

Cotton 1046 

Fine  lint 1032 

Beaver's  fur 1296 

Hare's  fur 1315 

Eiderdowai 1305 

In  another  series  of  experiments,  however,  using  the  same  materials 
differently  arranged,  very  different  results  were  obtained: 

Seconds. 

Sheep's  wool,  loosely  arranged 1118 

Woolen  thread,  wound  round  bulb 934 

Cotton,  loose 1046 

Cotton  thread,  wound  round  bulb 852 

Lint,  loose 1032 

Linen  thread,  wound  round  bulb 873 

Linen  cloth,  ditto 786 

From  these  experiments,  Rumford  showed  that  the  heat-retaining  value 
of  clothing  depends  more  on  its  texture  than  on  its  actual  material.  For 
further  consideration  of  this  subject,  see  Mattieu  Williams'  book  on 
The  Philosophy  of  Clothing. 

17.  Mineral  Fibers. — The  mineral  fibers  are  of  rather  rare  occurrence 
in  the  textile  industry  as  compared  with  the  extensive  use  of  the  preceding 
classes  of  fibers.  The  mineral  fiber  asbestos,  however,  is  finding  an 
increased  use  for  certain  purposes,  and  consequently  deserves  to  be  classi- 
fied and  considered  in  a  comprehensive  study  of  the  textile  fibers.     Asbestos 


SPUN   GLASS  11 

is  practically  the  only  natural  mineral  fiber  with  which  we  are  acquainted, 
the  other  mineral  fibers,  such  as  spun  glass  and  mineral  wool  or  slag  fiber, 
are  all  artificial  fibers,  and  are  better  considered  under  that  class. 

18.  The  Artificial  Fibers. — These  may  be  divided  into  two  groups: 
(a)  those  of  mineral  origin  and  (6)  those  of  animal  or  vegetable  origin. 
In  the  first  division  may  be  classed  such  fibers  as  spun  glass,  metallic 
threads,  and  slag  wool;  in  the  second  division  may  be  put  the  various 
artificial  silks,  such  as  lustra-cellulose  and  gelatine  silk. 

19.  Spun  Glass. — Fibers  of  spun  glass  are  prepared  by  drawing  out 
molten  glass  in  the  form  of  very  fine  threads.  It  is  said  that  such  threads 
can  be  drawn  out  so  fine  that  it  takes  about  1400  miles  of  the  fiber  to 
weigh  1  lb.  Colored  glasses  may  be  used  to  give  rise  to  variously  colored 
threads.  Owing  to  its  brittle  nature  and  lack  of  elasticity,  spun  glass 
receives  a  very  hmited  application,  it  being  made  into  various  ornamental 
objects,  and  sometimes  into  cravats.  Though  fabrics  composed  entirely 
of  glass  are  rare,  yet  colored  glass  threads  are  somewhat  used  for  the  weft 
in  silk  materials  for  the  purpose  of  producing  novel  effects,  as  the  glass 
gives  the  fabric  great  luster  and  stiffness.  A  variety  of  spun  glass  known 
as  glass  wool  is  used  to  some  extent  in  the  chemical  laboratory  as  a  filtering 
medium  for  hquids  which  would  destroy  ordinary  filter  paper.  Glass 
wool  is  curly,  this  property  being  given  to  it  by  drawing  out  the  glass  thread 
from  two  pieces  of  glass  of  different  degrees  of  hardness;  and  by  unequal 
contraction  on  cooling,  this  double  thread  acquires  a  set  curl. 

Spinning  glass  for  commercial  uses  is  an  important  new  industry  which 
has  been  developed  in  Venice  within  the  past  several  years.  The  spun  glass 
is  marketed  in  three  forms — hanks  of  spun  glass  thread  of  straight  fiber 
called  Cotone  di  Vetro  (glass  cotton),  masses  of  spun  glass  curled  fiber 
called  Lano  di  Vetro  (glass  wool),  and  either  of  the  above  qualities  pressed 
into  sheets  or  pads  from  i  to  |  in.  in  thickness  that  resemble  white  felt  pads. 
At  present  the  principal  use  made  of  this  product  is  for  insulation,  and 
especially  for  making  separators  for  accumulators  of  electricity;  but  the 
glass  wool  would  serve  admirably  for  making  artificial  hair,  wigs,  perukes, 
dolls'  hair,  Santa  Claus  beards,  and  other  purposes,  and  in  the  pad  form  it 
serves  as  a  hygienic  filter. 

The  processes  of  manufacture  are  simple.  Solid  glass  rods,  about 
2  ft.  6  ins.  long  and  of  the  thickness  of  a  lead  pencil,  are  made  of  pure 
soda  glass  that  contains  no  adulteration  of  lead  or  other  metal.  The 
absence  of  lead  and  adulterations  gives  the  quahty  of  perfect  flexibility 
to  the  fiber.  On  a  simple  desk  is  mounted  a  Bunsen  burner  or  gas  flame 
and  blowpipe.  By  the  side  of  the  desk  is  mounted  an  ordinary  bicycle 
wheel,  minus  the  rubber  tire,  that  revolves  rapidly  and  regularly  at  rhyth- 
mic speed  under  power  furnished  by  a  small  electric  motor.  A  girl  sits 
at  the  desk,  melts  the  end  of  the  glass  rod  in  the  flame  of  the  gas  burnw, 


12  GENERAL  CLASSIFICATION 

draws  it  to  a  thread  and  throws  the  thread  around  the  wheel.  If  the 
thread  breaks,  she  must  repeat  the  process;  if  not,  she  slowly  revolves 
the  end  of  the  rod  in  the  constant  flame,  and  it  is  automatically  spun  to 
a  very  thin  filament.  The  hank  of  thread  on  the  wheel,  when  it  has 
assumed  the  dimensions  of  a  bicycle  tire,  is  taken  off.  Separated  with  the 
fingers,  it  curls  and  fluffs  out  like  wool  if  the  thread  is  sufficiently  fine. 
It  is  packed  in  the  hank  as  glass  cotton,  in  the  fluff  as  glass  wool,  and  in 
the  compressed  form  as  glass  wool  or  cotton  according  to  the  fineness  of 
the  fiber.  The  cheaper  grades  of  spun  glass  formerly  came  from  Germany; 
it  is  claimed  that  the  Italian  article  is  superior. 

20.  Metallic  Threads. — Metal  yarns  or  threads  consisting  of  various 
metals  drawn  out  into  filaments  are  used  in  decorative  fabrics.  Gold, 
silver,  copper,  and  various  alloys  are  used  for  this  purpose,  the  metals 
being  heated  to  redness  or  until  they  are  in  a  softened  condition.  At 
the  present  time  metallic  threads  are  largely  imitated  by  coating  linen 
yarns  with  a  thin  film  of  gold  or  silver.  Threads  of  pure  gold  are  seldom 
made;  what  is  known  as  pure-gold  thread  is  a  fine  silver  wire  covered 
with  a  thin  layer  of  gold.  Silver  thread  is  sometimes  made  with  a  core 
of  copper  and  a  layer  of  silver.  Lyon's  gold  thread  consists  of  copper 
faced  with  gold.  Metallic  threads  are  usually  made  into  a  flattened  or 
band-like  form  by  rolling.  By  twisting  with  silk  or  woolen  yarns,  the 
so-called  brilliant  yarns  are  made.  The  Cyprian  gold  thread  of  old 
embroideries  consists  of  a  linen  or  silk  thread  around  which  is  twisted  a 
cover  of  gilded  catgut. 

Bayko  metal  yarn  is  a  textile  product  recently  introduced.  It  consists 
of  a  core  of  cotton,  silk,  or  other  thread,  which  is  coated  with  a  solution 
of  cellulose  acetate  containing  in  suspension  finely  divided  particles  of 
metals.  The  yarn  is  thus  given  a  metallic  coating,  yet  furnishes  a  durable 
and  flexible  thread.  Microscopical  examination  of  this  yarn  shows  each 
filament  to  consist  of  a  core  or  nucleus,  and  an  enveloping  layer.  The 
core  is  usually  a  twofold  cotton  thread,  while  the  envelope  is  a  colorless 
to  pale  yellow  substance.  The  average  cross-section  of  a  single  filament 
is  0.0372  sq.  mm.  The  cross-section  of  the  envelope  is  0.0133  sq.  mm., 
or  35.8  percent  of  the  total.  The  metric  size  averaged  29.6;  the  thickness 
of  the  filament  0.191  mm.;  the  tensile  strength  averaged  462  gms.,  and 
the  elasticity  4.9  percent. 

Another  process  of  metallising  yarn  consists  in  coating  the  yarn  with 
a  solution  containing  a  metallic  powder  and  an  adhesive  liquid.  Casein 
has  been  used,  but  the  adhesion  is  not  durable.  Others  have  preferred 
gelatin  which  adheres  to  the  yarn  more  firmly,  but  is  open  to  the  objection 
of  being  very  hygroscopic,  causing  mold.  Attempts  have  been  made 
to  protect  the  metallised  yarn  against  the  action  of  moisture  by 
applying  a  transparent  solution  of  celluloid  or  collodion,  but  this  gives  the 


SLAG  WOOL  13 

yarn  a  lustrous  appearance  different  from  that  of  metal.  Edmond  Dhun- 
nausen  has  found  after  repeated  experiments  that  casein  glue  adheres 
firmly  when  the  yarn  has  been  previously  treated  with  a  mixture  of  gelatine 
and  a  powder  insoluble  in  that  material.  The  casein  glue  is  loaded  with 
the  metallic  powder  to  give  the  desired  appearance.  The  yarn  is  passed 
through  a  bath  consisting  of : 

Gelatine 25  parts 

Metallic  powder 25     " 

Water 25     " 

After  drying  for  about  twenty  minutes  the  yarn  is  passed  through  a 
bath  made  up  as  follows : 

Casein 15  parts 

Borax 5     " 

Water 80     " 

Metallic  powder -. 30     " 

After  drying  a  second  time  very  rapidly  the  yarn  is  passed  through  a 
second  bath  of  the  same  composition.  The  weight  of  the  metallic  powder 
used  varies  according  to  the  specific  gravity  and  the  nature  of  the  material. 
The  effect  can  be  varied  by  adding  different  colors  to  the  last  bath. 

Probably  the  most  successful  method  for  metallising  yarns  or  fabrics, 
and  for  the  making  of  metallic  prints,  is  the  use  of  Bakelite  (a  formaldehyde 
condensation  product  of  phenol)  as  a  medium  and  binder  for  the  metallic 
powder.  This  process  was  developed  by  Zundel  at  Moscow.  Another 
process  for  the  metallisation  of  fabrics  is  described  by  Lang  ^  as  follows: 
"  A  solution  of  India  rubber  in  naphtha  or  other  solvent  is  prepared  and  a 
metallic  powder  added  and  the  whole  mixed  until  a  homogeneous  liquid  is 
obtained.  The  fabric  is  wetted  in  the  liquid  and  dried.  A  trace  of  amyl 
acetate  may  be  added  to  the  liquid  to  give  a  better  luster.  An  example  is 
given  in  which  16  parts  by  weight  of  naphtha,  2  of  India  rubber,  2  of 
metallic  powder  and  0.5  of  amyl  acetaie  arc  used." 

Metallic  threads  are  used  for  quite  a  large  numbe'r  of  fabrics,  such  as 
passementerie  work,  trimmings,  brocades,  decorative  embroidery,  church 
vestments,  fancy  costumes,  tapestries,  fancy  vostings,  etc. 

21.  Slag  WooL — Slag  wool  is  prepared  by  blowing  steam  through 
molten  slag;  it  can  scarcely  be  called  a  textile  fiber,  but  it  is  used  in  some 
degree  as  a  packing  material.  It  (also  known  as  mineral  wool  and  in 
England  as  silicate  cotton)  is  an  interesting  bj-product  from  the  blast 
furnace.  The  process  of  manufacture  consists  in  subjecting  a  small 
stream  of  molten  slag  to  a  strong  blast  of  steam  or  compressed  air.  This 
has  the  effect  of  breaking  it  up  into  minute  spherules,  and  each  small  bead 
particle  as  it  is  blown  away  carries  behind  it  a  thread  of  finely  drawD-out 

1  Fr.  Pat.  509,492. 


14  GENERAL  CLASSIFICATION 

slag,  thus  forming  extremely  delicate  filaments  resembling  fine  glass 
threads.  These  fine  threads  are  often  2  to  3  ft.  in  length,  but  readily 
break  up  into  smaller  ones  and  in  bulk  look  like  a  mass  of  cotton  of  a 
dingy  white  color.  The  fiber  is  classified  according  to  fineness  into  two 
grades  (1)  ordinary,  including  all  fiber  weighing  over  14  lbs.  and  less  than 
24  lbs.  per  cubic  foot;  and  (2)  extraordinary,  including  fiber  weighing  less 
than  14  lbs.  per  cubic  foot.  Slag  wool  has  the  property  of  great  lightness 
combined  with  that  of  being  absolutely  fireproof;  it  is  also  a  very  good 
non-conductor  of  heat  and  sound.  Slag  wool  is  not  spun  into  yarns  or 
made  into  fabrics  after  the  manner  of  asbestos,  but  is  used  as  a  felt  consist- 
ing of  fine,  interlocking  mineral  fibers  enclosing  a  mass  of  minute  air  cells 
which  gives  it  the  propei'ty  of  being  such  a  good  non-conductor  of  heat. 
Coleman,  in  this  connection,  gives  the  following  table  showing  the  relative 
heat-conducting  powers  of  various  materials: 

Slag  wool .  .  100 

Hair  felt 117 

Cotton  felt 122 

Sheep's  wool 136 

Air  space 280 

The  fibers  of  slag  wool  are  very  brittle  and  the  fine,  sharp  points  readily 
cut  into  the  skin.  In  factories  making  this  material  care  should  be  taken 
to  properly  protect  the  workmen  from  getting  the  fine  needlelike  particles 
into  the  eyes  and  lungs.  Another  disadvantage  of  slag  wool  is  that  it 
usually  contains  sulfur,  so  when  it  is  in  contact  with  water  or  moisture, 
sulfuric  acid  is  gradually  formed,  which  may  result  in  the  corrosion  of 
metallic  surfaces.  This  defect  may  be  obviated  by  the  selection  of  slag 
free  from  sulfur  for  the  preparation  of  the  fiber. 

22.  Artificial  Silks. — Artificial  silks  are  made  from  cellulose  derivatives 
by  forcing  solutions  of  these  through  fine  capillary  tubes,  coagulating  the 
resulting  threads,  and  subsequently  subjecting  them  to  various  processes 
of  chemical  treatmelit.  As  these  belong  more  strictly  to  the  class  of  true 
textile  fibers,  they  will  be  given  a  more  extensive  consideration,  in  a  further 
section,  as  being  derivatives  of  cellulose. 

23.  Other  Forms  of  Artificial  Fibers. — During  the  World  War  a  number 
of  different  artificial  fibers  were  developed  in  Germany.  One  of  these  is 
interestingly  described  as  follows:  By  grinding  with  water  in  a  ball-mill  or 
other  suitable  means,  wool,  hairs,  horn,  leather,  and  their  wastes,  such  as 
dust,  clippings,  and  short  fibers  which  are  too  small  of  themselves  to  permit 
of  their  use  in  the  ordinary  way,  can  be  very  finely  divided.  While 
finely  ground  substances  of  this  kind  cannot  be  used  for  the  manufacture 
of  paper  except  under  great  difficulties,  as  there  is  no  cohesion  between 
the  individual  particles,  nor  can  they  be  used  for  artificial  silk  manufacture, 


FIBER  MICROSCOPY  15 

it  has  been  found  that  it  is  possible  to  produce  from  these  substances 
fibers  which  can  be  spun.  This  is  done  by  making  films  by  forming  a 
solution  of  the  wastes  in  question  with  suitable  substances  such  as  gelatine, 
size,  acetyl  cellulose,  or  other  viscous  solutions  of  cellulose  or  cellulose 
compounds.  The  films  are  cut  up  into  fine  fibers  which  are  suitable  for 
spinning,  or  the  films  are  cut  into  strips,  or  produced  in  strip  form  so  that 
these  can  be  spun  in  the  manner  adopted  for  paper  yarns.  By  this  method 
new  fibers  and  spun  yarns  can  be  produced  which — especially  when  gelatine 
or  size  is  the  binding  medium — possess  the  properties  of  wool  to  a  very 
high  degree.  In  order  to  render  gelatine  or  size  (glue)  insoluble,  the 
necessary  quantity  of  a  chrome  compound  (bichromate  or  chi-ome  alum) 
is  added  to  the  mixture.  Materials  for  producing  pliability  can  be  added, 
such  as  glycerol  or  certain  ester  compounds,  such  as  triphenyl  phosphates. 
Oils  and  fats  can  also  be  added,  especially  those  that  do  not  dry  and  that 
form  emulsions  easily. 

The  film  may  be  experimentally  produced  as  follows: 
Upon  a  13X18  cm.  glass  plate  covered  with  a  thin  laj^er  of  wax  the 
following  mixture  is  worked  up,  evenly  distributed  and  then  dried  at  a 
moderate  temperature : 

12      cc,  of  a  5  percent  solution  of  gelatine. 
3      cc.  of  a  10  percent  paste  of  the  finest  ground  wool. 
0.5  cc.  of  glycerol. 
1.2  cc.  of  a  5  percent  chrome  alum  solution. 

When  this  mixture  is  dry  it  forms  a  non-curling  elastic  film  about 
0.07  mm.  thick,  which  can  easily  be  removed  from  the  wax  coating.  Thin 
or  thick  films  can  be  obtained  according  to  the  quantity  of  the  mixture. 
Even  films  of  0.03  mm.  have  been  found  to  be  of  use.  These  films  can  be 
cut  into  extremely  fine  fibers  by  employing  suitable  cutting  devices; 
and  then  they  may  be  spun  alone  or  mixed  with  other  fibers.  Instead  of 
using  the  binding  medium  mentioned  above,  the  finely  ground  wastes  can 
be  mixed  with  paper  pulp,  paper  being  obtained  from  the  mixture;  this 
is  then  parchmented  in  the  ordinary  manner  with  a  sulfuric  acid  of  1.7 
sp.  gr.  or  with  a  warm  solution  of  zinc  chloride  of  1.9  sp.  gr.,  and  then 
washed.  In  this  way  parchment  papers  can  be  obtained  which  have  a 
wool  content  of  50  percent  and  more,  and  which  by  suitable  treatment 
and  additions  can  be  made  pliable  and  waterproof. 

24.  Fiber  Microscopy. — The  examination  of  textile  fibers  under  the 
microscope  is  a  very  important  and  essential  aid  to  a  study  of  these 
materials.  Microscopy  in  any  case  requires  the  acquisition  of  a  certain 
amount  of  delicate  technique  and  skill  on  the  part  of  the  observer,  and 
this  h  particularly  true  in  the  case  of  fiber  microscopy.  A  knowledge 
of  the  proper  methods  of  preparing  specimens  for  examination,  of  mount- 


16  GENERAL  CLASSIFICATION 

ing  them  and  of  the  proper  selection  of  lenses,  is  of  importance.  The 
markings  and  the  structure  of  the  various  fibers  can  only  be  brought  out 
in  their  characteristic  appearance  by  the  employment  of  careful  skill  and 
this  can  only  be  developed  by  considerable  practice  and  a  close  knowledge 
of  the  possibilities  of  the  microscope.  The  preparation  of  micrographs 
and  of  microphotographs  so  as  to  bring  out  the  characteristic  features  of 
the  specimens  under  examination  also  requires  considerable  study  and 
experience,  and  in  the  latter  case,  an  additional  knowledge  of  the  possi- 
bilities and  limitations  of  photography. 

It  is  not  possible  at  this  point  to  take  up  in  detail  the  subjects  of 
microscopy  and  its  related  branches,  although  it  will  be  well  to  present 
to  the  reader  some  of  the  leading  features  relating  particularly  to  the  field 
of  fiber  microscopy,  with  a  brief  consideration  of  the  apparatus  required 
and  the  methods  of  preparing  and  examining  the  specimens. 

In  the  first  place,  a  fairly  good  microscope  is  required,  with  a  good 
system  of  the  best  lenses.  While  excessive  magnification  is  not  neces- 
sary, the  lens  system  should  be  selected  so  as  to  obtain  a  clear  flat  achro- 
matic field  which  will  admit  of  a  good  focus  over  a  considerable  area. 
It  must  be  borne  in  mind  that  fillers  are  more  or  less  rounded  filaments 
and  are  not  thin,  flat  specimens  like  the  delicate  cross-sections  of  objects 
that  are  mostly  the  subjects  used  in  microscopy.  On  this  account  it  is 
necessary  to  have  a  good  depth  of  focus  in  order  to  prevent  undue  distor- 
tion of  the  fiber  which  might  lead  the  unskilled  observer  to  a  very  errone- 
ous idea  of  the  markings  on  the  subject.  A  verj-  complete  range  of  mag- 
nifications may  be  obtained  with  the  use  of  No.  5  and  No.  10  eye-pieces  in 
combination  with  the  following  objectives:  f  in.  (16  mm.),  §  in.  (4  mm.) 
and  iV  in.  (1.9  mm.).  The  last-named  objective  requires  an  oil  immersion 
system  and  is  only  used  for  very  high  powers  and  delicate  work  which 
would  be  somewhat  out  of  the  ordinary. 

The  following  table  gives  the  various  magnifications  available  with 
the  objectives  and  e^'e-pieces  mentioned: 

Objective.  Eye-pieces. 

No.  5.  No.  10 

§  in.  or  16  mm.  50  100 

i  in.  or  4  mm.  215  430 

^  in.  or  1.9  mm.  475  950 

It  is  well  to  have  a  microscope  set  fitted  with  a  revolving  nose-piece 
for  two  or  three  objectives  so  that  the  fiber  may  first  be  picked  up  with 
a  low  power  and  then  observed  finally  with  a  suitable  high  power.  An 
adjustable  stage  is  also  convenient  for  moving  the  specimen  mount  and 
for  locating  positions.  The  use  of  a  sub-stage  diaphragm  and  condenser 
for  obtaining  proper  conditions  of  illumination  is  also  quite  important  in 


FIBER  MICROSCOPY 


17 


good  fiber  microscopj^,  as  veiy  frequently  important  points  of  observation 
can  only  be  brought  out  by  adjusting  the  illumination  of  the  specimen. 
An  achromatic  sub-stage  condenser  and  an  iris  diaphragm  are  usually 
supplied  with  the  better  sets  of  microscopes.  The  accompanying  illus- 
tration (Fig.  4)  shows  a  popular  form  of  microscope  with  the  necessary 


E— Eyepiece 


D  Draw  TiJbe 


Miorometer  ^^U 
Head 


Handle  Arr 


accessories  suitable  for 
fiber  investigations. 

Fiber  specimens  may 
be  mounted  in  various 
waj^s;  for  temporary 
mounts  and  rapid  ob- 
servation an  ordinary 
water  mount  may  be 
used .  The  fibers  should 
be  well  separated  so 
that  as  few  as  possible 
cross  over  one  another, 
and  if  necessary  cut  in 
short  lengths  to  come 
within  the  area  of  the 
cover  glass.  These  fibers 
are  then  laid  neatly  on 
the  glass  slide,  a  drop 
of  water  is  touched  to 
them  by  means  of  a 
dropper  or  a  glass  rod, 
and  then  the  cover  glass 
is  laid  over  them  and 
gently  pressed  down  so 
as  to  flatten  out  the 
specimen.  In  making 
observations  under  high 
power  it  is  especially 
necessary  that  the  fibers  Fig.  4  —Diagram  of  Microscope  Showing  Essential  Parts, 
be  as  single  as  possible, 

for  if  several  are  piled  up  across  one  another  the  focus  becomes  distorted, 
and  unless  the  observer  is  skilled  in  these  observations  he  may  mistake 
shadows  for  important  markings.  The  water  mount  is  only  of  a  temporary 
character,  as  the  cover  glass  is  just  loosely  held  in  place  and  the  water 
quickly  evaporates.  Where  a  permanent  mount  is  desired,  or  where  it 
is  necessary  to  have  a  very  flat  field  for  high  power  observation,  the  speci- 
men may  be  mounted  in  Canada  Balsam,  which  dries  like  a  varnish  and 
cements  the  cover  glass  firmly  in  place.     This  kind  of  mounting,  however, 


1 8 -Stage 


SS-Sui  Stage 


B-Base 


18 


GENERAL   CLASSIFICATION 


generally  makes  the  fiber  very  transparent  and  may  obliterate  many  of 
the  characteristic  markings  both  on  the  surface  and  in  the  interior. 
To  bring  out  these  markings  it  may  be  necessary  to  first  treat  the  speci- 
men with  certain  reagents,  such  as  various  stains  used  especially  in  micros- 
copy, silver  nitrate  and  other  chemicals.  Glycerol,  cedar  oil  and  some 
other  mediums  are  also  used  at  times  for  mounting  fiber  specimens.  The 
effect  of  mounting  in  different  media  is  shown  in  Fig.  5,  which  shows  a 
fiber  of  Egyptian  cotton  mounted  as  follows:    (1)  plain  air  mount;    (2) 


Fig.  5.— Cotton  Fibers  Mounted  in:    (A)  Air,  (B)  Water,  (C)  Glycerol,  (D)  Cedar 
oil,  {E)  Anisol,  (F)  Mono-bromnaphthalene.     (Herzog.) 


in  water;    (3)  in  glycerol;    (4)  in  cedar  oil;    (5)  in  anisol;    (G)  in  mono- 
bromnaphthalene. 

It  is  often  desirable  to  draw  the  appearance  of  the  fiber  under  the 
microscope  so  as  to  preserve  a  permanent  record.  For  this  purpose 
several  forms  of  projection  attachments  to  the  microscope  are  available, 
such  as  the  Abbe  ocular  shown  in  Fig.  6.  Another  form  of  apparatus  is 
shown  in  Fig.  7.  Both  of  these  instruments  project  the  image  down  on 
a  piece  of  paper  on  which  the  outlines  are  drawn.  A  more  satisfactory 
though  more  complicated  and  costly  equipment  for  projection  drawing  is 


FIBER   MICROSCOPY 


19 


shown  in  Fig.  8.  In  making  these  drawings  or  micrographs,  however,  a 
certain  amount  of  skill  and  talent  at  drawing  is  required,  but  this  can  be 
developed  with  experience  and  painstaking  care.     It  is  usually  necessary 


Fig.  6. — Abbe  Projection  Apparatus  for  Drawing  from  Microscope. 
(Bausch  &  Lomb.) 


for  the  observer  to  possess  good  draughting  abilities,  however,  to  obtain 
satisfactory  results. 

A  polariscopic  attachment  is  also  of  considerable  use  in  the  observa- 
tion of  fibers  under  the  microscope,  as 
this  brings  out  the  interior  structure 
of  the  fiber  in  a  remarkable  manner; 
it  is  especially  useful  in  obtaining 
good  micro-photographs  where  struc- 
tural qualities  are  desired  (see  Fig.  9). 

To  obtain  permanent  records  of 
fiber  microscopy  so  that  the  appear- 
ance of  the  specimen  may  be  studied 
and  observed  at  leisure,  it  is  neces- 
sary to  use  a  photographic  attachment 
whereby  a  real  photograph  may  be 
taken  of  the  magnified  object.  A  very 
useful  form  of  such  an  apparatus 
is  shown  in  Fig.  10,  and  it  is  well  to  use 
a  special  electric  lamp  for  illumina- 
tion so  as  to  obtain  a  clear  image  and  permit  of  a  negative  being  taken 
in  a  reasonably  short  time. 


Fig.  7. — Attachment  used  for  Projection 
Drawing.     (Bausch  &  Lomb.) 


20 


GENERAL   CLASSIFICATION 


Cross-sections  of  fibers  for  microscopic  mounts  may  be  made  by  taking 
a  small  strand  of  fibers  arranged  in  as  parallel  a  fashion  as  possible  and 
imbedding  them  in  a  special  preparation  of  melted  wax,  allowing  the  speci- 


FiG.  8. — Micro-Projection  and  Drawing  Lcjuipment.     (Bausch  &  Lomb.) 

men  to  cool  and  then  cutting  thin  cross-sections  on  a  ii.icrotome  (see  Fig. 
11).  Further  details  as  to  such  preparations  will  be  considered  under  the 
microscopic  examination  of  the  various  fibers. 


iuftllSBUB"* 


Fig.  9. — Polariscopic  Attachment  for  Microscope;  (A)  Polariser,  (B)  Analyset 

(Bausch  &  Lomb.) 


A  very  necessary  adjunct  for  the  measurement  of  fiber  diameters  is 
the  micrometer  ocular.  This  not  only  serves  for  the  simple  observation 
of  fibers,  but  also  for  their  measurement.  For  this  purpose,  a  glass  plate 
on  which  a  small  scale  is  etched  is  placed  between  the  ocular  and  the  con- 
densing lens.     Sometimes  the  scale  is  photographed  on  the  plate.     It  is 


FIBER   MICROSCOPY 


21 


usually  a  centimeter  divided  into  100  parts,  or  a  half-centimeter  divided 
into  50  parts.  If  a  fiber  of  a  certain  thickness  is  examined  several  times 
successively  with  this  micrometric  ocular,  but  with  different  objectives, 
it  will  be  noticed  that  the  divisions  on  the  scale  always  remain  the  same 
size,  but  the  fiber  will  appear  larger  or  smaller  depending  on  the  strength 


Fig.  10. — Installation  for  Preparing  Photomicrographs  of  Fibers. 
(Bausch  &  Lomb.) 


of  the  objective.  From  this  it  is  evident  that  a  division  on  the  micro- 
metric  scale  will  have  different  values,  depending  upon  the  lens  system 
with  which  it  is  used.  The  ocular  micrometer  is  therefore  standardised 
for  each  system  on  an  objective  micrometer,  which  is  a  very  finely  divided 
scale  ruled  on  glass. 

25.  Statistical. — The  industries  related  to  the  preparation  and  utilisa- 
tion of  textile  fibers  rank  among  the  most  important  in  the  industrial  life 


22 


GENERAL   CLASSIFICATION 


of  all  nations.  In  the  United  States  the  cotton,  wool  and  silk  industries 
are  of  vast  extent,  not  only  with  respect  to  the  manufacturing  part,  but 
also  to  the  merchandising  and  distribution  of  the  products.  In  Englantl 
the  cotton  and  woolen  industries  form  the  chief  sources  of  the  wealth  of 
the  nation.  In  our  own  country  the  cotton  industry  ranks  easily  first  with 
a  capital  investment  of  nearly  two  billions  of  dollars  and  with  a  yearly 
value  of  products  exceeding  this  sum.  Second  in  importance  come  the 
industries  related  to  the  wool  fiber,  including  woolen  and  worsted  goods. 
A  very  close  third  is  the  silk  industry,  with  a  capitalisation  of  over  half 
a  billion  dollars,  and  with  a  present  output  of  about  three-fourths  of  a 


Fig    11. — Microtome  for  Cutting  Fiber  Sections.     (Bausch  &  Lomb.) 


billion  dollars  in  value  of  manufactured  goods.  To  the  fiber  industries 
proper  must  also  be  added  that  relating  to  the  manufacture  of  artificial 
silk,  though  this  is  considered  more  specifically  under  the  term  of 
chemical  industry.  The  size  of  this  latter  industry  is  growing  with 
great  rapidity  in  this  country,  and  will  soon  rank  with  the  silk  industry 
itself  in  importance  and  economic  value. 

The  following  table  shows  the  extent  of  the  fiber  industries  in  the 
United  States  for  the  year  1919  {Census  Reports) : 


STATISTICAL 


23 


o 


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00  i-H  rsi  t-H  rH  i-H 


w 


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0505iX)t^0005(NiOCOTl<0050iO-^CO»0-*i-HiOOOOGOI>i-HiC 

COOCC<liO  T-H  (Ml— I  I— I  I--.  ,—1 


M  B 


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lo  cTco'co  oi^o'c^f  co~'t"co''"*'"ic  c't-'^co'co" 
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'co"'*"of     x"o"x"x"x"or'^".-ri>ric-r     ofr-Tcoco" 


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II 

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o ::::  3  TJ 


CHAPTER  II 


ASBESTOS  AS  A  TEXTILE  FIBER 


1.  Occurrence. — The  principal  and,  strictly  speaking,  the  only  mineral 
fiber  is  asbestos;  which  occurs  in  nature  as  a  mineral  of  that  name.  The 
word  is  derived  from  the  Greek  and  was  used  by  Dioscorides  and  other 
Greek  writers  as  a  term  for  quicklime,  but  Pliny  fixed  its  meaning  in  its 
modern  sense.  It  is  a  fibrous  silicate  of  magnesium  and  calcium,  though 
often  containing  iron  and  aluminium  in  its  composition,  especially  in  the 
dark-colored  varieties.  The  general  term  "asbestos"  includes  the  fibrous 
varieties  of  both  serpentine  and  hornblende.  Serpentine  is  a  compound 
silicate  of  magnesium  and  calcium,  always  containing  iron,  and  generally 
also  some  manganese.  Hornblende  (also  known  as  amphibole)  is  very 
similar  in  composition,  but  often  contains  aluminium. 

The  composition  of  asbestos  from  different  parts  of  the  world  differs 
considerably,  as  the  following  analyses  indicate: 


C>iorus, 
Percent. 

Italy, 
Percent. 

Thetford, 

Canada, 

Percent. 

Templite, 
Percent. 

Silica  (SiOa) 

40.50 

1.09 

4.87 

39.02 

13.47 

40.30 

2.27 

0.87 

43.37 

13.72 

40.57 

0.90 

2.81 

41.50 

13 .  55 

40.52 

Alumina  (AI2O3) 

2.10 

Iron  oxide  (Fe^s) 

1.97 

Magnesia  (MgO) 

Water  (HoO) 

42.05 
13.46 

Canadian  asbestos  is  considered  best,  and  provides  about  75  percent  of 
the  world's  consumption  of  this  material. 

The  asbestos  mineral,  though  in  the  form  of  a  hard  rock,  can  be  easily 
separated  into  slender  white  fibers  (Figs.  12,  13  and  14),  sometimes  inclin- 
ing toward  a  greenish  color.  The  asbestos  mineral  has  a  density  of  2.5 
to  2.8,  and  a  hardness  of  3  to  5.  The  individual  fibers  of  asbestos  are  so 
fine  as  to  approach  the  limits  of  microscopic  measurement,  which  is 
^  micron  =  0.0005  mm.^     There  is  no  reason  for  supposing  that  these 

1  The  micron  is  a  unit  of  measurement  much  used  in  microscopic  work;  it  is 
equivalent  to  one-thousandth  millimeter.  The  symbol  mu  or  Greek  letter  ju  is  often 
used  for  the  term  micron. 

24 


VARIETIES   OF  ASBESTOS 


25 


Fig.  12. — Chrysotile  Asbestos  from  Canada. 


extremely  fine  fibers  of  asbestos  may  not  be  capable  of  still  further  sub- 
division; in  fact,  there  appears  to  be  scarcely  any  limit  to  this  possible 
subdivision  (see  Fig.  15).  The  asbestos  fiber,  however,  is  evidently  a 
crystal  and  is  angular 
and  not  round;  pre- 
sumably the  cross- 
section  is  square, 
though  this  has  yet 
to  be  definitely  estab- 
lished. Owing  to  the 
unlimited  splitting  of 
the  fiber  it  is  difficult 
under  the  microscope 
to  determine  its  proper 
form. 

2.  Varieties  of  Asbestos. — The  fibers  of  some  varieties  are  curly,  and 
afford  the  best  material  for  spinning.  Italy  was  perhaps  the  first  of  modern 
nations  to  use  asbestos  as  a  textile  material.  Experiments  in  this  fine 
were  encouraged  in  Lombardy  by  Napoleon  I,  but  it  was  not  until  about 

1866  that  any  practical 
commercial  results  were 
obtained,  and  both  asbes- 
tos cloth  and  paper  were 
made.  No  serious  at- 
tempt was  made  to  mine 
Canadian  asbestos  until 
1878,  when  the  valuable 
deposits  at  Thetford  and 
Black  Lake  in  Quebec 
were  exploited.  The  finest 
quality  of  long  "floss" 
asbestos  fiber  is  still  ob- 
tained from  the  Italian 
mineral.  There  is  a  piece 
of  asbestos  cloth  in  the 
Vatican  Museum  said  to 
date  from  Roman  times; 
it  is  of  rather  coarse  con- 
struction and  was  evidently  made  by  spinning  the  asbestos  with  vege- 
table fiber  (linen) .  Asbestos  cloth  was  noted  by  Marco  Polo  (thirteenth 
century)  in  his  travels  in  Tartary  and  China.  The  lamp  wicks  men- 
tioned by  Plutarch  as  used  in  the  "perpetual"  lamps  of  the  Vestal 
Virgins  were  made  of  asbestos  fiber.     Pausai!ii,as  refers  to  such  wicks 


Fig. 


13. — Piece  of  Asbestos  Rock  as  Mineral. 
(Johns-Manville  Co.) 


26 


ASBESTOS   AS   A   TEXTILE   FIBER 


as  made  from  ''Carpasian"  linen,  evidently  meaning  the  mineral  fiber 
obtained  from  Carpasiiis  in  Cyprus. 

Asbestos  fiber  is  known  in  Germany  as  " steinflachs "  (stone-flax),  in 
Italy  as  "amiantho,"  and  the  French  Canadian  calls  it  "pierre  a  coton" 
(cotton-stone). 

The  Italian  asbestos  (see  Fig.  16)  is  mineralogically  distinct,  both  in 
form  and  appearance,  from  the  Canadian  chrysotile.  Notwithstanding 
their  physical  differences,  however,  their  chemical  composition  is  very 


Fig.  14. — Asbestos  Rock  Broken  Apart  Showing  Fine  Fibrous  Structure. 
(Johns-Manville  Co.) 


similar,   and   when   reduced   to   commercial   fiber,    they   are   practically 
identical. 

The  blue  asljestos  of  South  Africa  is  the  mineral  crocidolite.  The  fiber 
is  easily  separated  by  the  fingers;  the  sp.  gr.  is  3.20  to  3.30;  the  luster  is 
very  silky  and  the  color  is  a  dull  lavender  l)lue,  due  to  the  presence  of 
ferrous  oxide.  The  fibers  are  quite  elastic  and  often  several  inches  long. 
Its  chemical  composition  is  quite  different  from  either  chrysotile  or  Italian 
hornblende,  l:)eing  as  follows: 

Percent. 

Silica 49.6 

Iron  sesquioxide 22 . 0 

Iron  protoxide 19.8 

Soda 8.6 


VARIETIES  OF  ASBESTOS 


27 


As  compared  with  Canadian  asbestos  it  has  a  high  tensile  strength  but  poor 
heat-resisting  quahties,  and  this  greatly  limits  its  commercial  value. 

There  is  considerable  confusion  and  misconception  as  to  the  proper 
mineralogical  character  of  asbestos,  and  this  has  probably  arisen  from 
the  use  of  the  name  in  a  somewhat  generic  sense.  Dana,  in  his  Mineralogy, 
says  that  asbestos  is  a  finely  fibrous  form  of  hornblende,  but  much  that 
is  so  called  is  fibrous  serpentine.  This  statement  seems  to  have  divided 
most  writers  on  the  subject  into  two  camps,  the  one  calling  the  mineral 
a  variety  of  hornblende,  while  the  other  claims  it  to  be  derived  from 
serpentine.  The  asbestos  of  commerce  is  really  a  hydrated  silicate  of 
magnesium,  of  the  same  com- 
position as  ordinary  serpen- 
tine rock;  in  other  words,  it 
is  a  fibrous  serpentine. 

In  a  mineralogical  sense 
the  term  asbestos  is  really  a 
generic  one,  and  the  mineral 
occurs  in  a  variety  of  species, 
some  of  which  are  much  more 
valuable  than  others  for  fiber 
purposes.  In  some  the  fibers 
are  slender  and  easilj^  separ- 
able, and  of  a  white  or  green- 
ish color.  A  variety  known 
as  amianthus  gives  fibers  of 
a  fine  silky  quality.  Ligni- 
form  asbestos  is  a  hard  com- 
pact variety ,  resembling  petri- 
fied A^ood  in  appearance,  and 

brownish  to  yellowish  in  color;  a  wool-like  variety  found  near  Vesuvius 
is  known  as  breislakite.  Mountain  flax,  mountain  cork,  and  mountain 
leather  are  all  varieties  of  asbestos,  the  last  consisting  of  a  naturally  felted 
mass  of  asbestos  fibers. 

The  chief  commercial  variety  of  asbestos  is  a  form  of  serpentine  and 
it  differs  from  the  hornblende  variety  in  that  it  contains  about  14  percent 
of  water  in  its  composition.  Picrolite  is  another  fibrous  variety  of  ser- 
pentine and  closely  resembles  coarse  asbestos  (see  Fig.  17).  It  occurs  in 
nearly  all  Canadian  asbestos  mines  and  is  known  as  bastard  asbestos.  The 
fiber  is  sometimes  very  long  (over  a  foot)  but  is  harsh  and  brittle  and 
unsuited  for  commercial  purposes. 

Chrysotile  asbestos  furnishes  the  most  valuable  commercial  fiber  as  it 
combines  the  best  length  and  fineness  of  fiber  with  infusibility,  tensile 
strength  and  flexibility.     These  factors  must  always  be  taken  into  con- 


FiG.  15. 


-Asbestos  Fiber .     ( X  5 . ) 
by  author.) 


(Micrograph 


28 


ASBESTOS   AS   A   TEXTILE   FIBER 


sideration  when  judging  the  suitabiHty  of  any  mineral  fiber,  and  though 
there  are  several  other  minerals  of  a  fibrous  silky  character,  their  fibers 


Fig.  16. — Italian  Asbestos  from  Hornblende. 

usually  fail  to  compare  favorably  with  chr^ysotile  asbestos.     The  heat- 
resisting  qualities  of  both  amphibole  asbestos  and  chrysotile  asbestos  are 


Fig.  17. — Picrolite  or  Bastard  Asbestos  of  Long  Fiber. 


good,  but  where  strength  of  fiber  and  spinning  quality  are  desired,  the    a 
chrysotile  variety  is  much  superior.  f 


VARIETIES  OF  ASBESTOS 


29 


The  difference  in  the  chemical  composition  of  chrysotile  and  amphibole 
asbestos  is  given  in  the  following  typical  analyses: 


Chrysotile, 

Canadian, 

Percent. 

Amphibole, 
Percent. 

Silica  (SiO-,) 

41.90 

42.52 

0.89 

0.69 

14.05 

61.82 
23.98 
1.12 
6.55 
1.63 
5.45 

Magnesia  (MgO) 

Alumina  (Al.Os) 

Iron  o.xide  (FcoOs) 

Lime  (CaO) 

Water  (H2O) 

It  appears  that  the  greater  the  amount  of  water  in  an  asbestos,  the 
better  and  finer  is  the  quality  of  its  fiber.  With  a  small  percentage  of 
water  the  fiber  becomes  brittle  and  will  not  spin.  The  softness  of  the  fiber 
is  proportional  to  the  water  content;  a  very  silky  asbestos  may  contain 
15  percent  of  water,  whereas  that  containing  11  percent  or  less  is  brittle 


■■ 

^^Hr^^M 

■ 

■ 

^^^^^^BV^^^^Vjfl^^^^HH 

H^^^^^^^^H 

MBjj^g^^M 

jHBi^'  'V^m 

WKf^' 

3H 

■I'P^''^ 

B"^^.^'- 
P^-% 

V    *           ' 

'■*^r^^B 

^h4,^ 

.  J- 

*  '^H 

^Hmv 

'     m^' 

I^'^^l 

^^HS^t' 

_    ;;^  -                '^'i'. 

.^^^M^Kmit 

^B^     ;,,^>' 

1 

Fig.  18. — Crushed  Asbestos  Previous  to  Carding  and  Spinning. 
(Johns-Manville  Co.) 

and  harsh.  If  a  soft-fibered  variety  of  asbestos  is  subjected  to  a  high 
heat,  a  portion  of  its  combined  water  will  be  driven  off,  and  the  fiber  will 
then  lose  its  flexibility  and  spinning  qualities. 

The  fibers  of  chrysotile  are  to  be  distinguished  from  those  of  horn- 
blende by  the  fact  that  the  fiber-bundles  of  the  former  are  partly  decom- 
posed by  hythochloric  acid  and  completely  so  by  sulfuric  acid,  whereas 


30 


ASBESTOS   AS   A  TEXTILE   FIBER 


hornblende  (or  amphibole)  asbestos  is  not  acted  upon  by  either  acid. 
Chrysotile  asbestos  is  also  the  denser,  and  is  of  a  white,  straw -yellow  to 
brown,  or  bluish  color,  depending  on  the  content  of  iron  oxide  (which  is 
sometimes  as  much  as  30  percent).  The  amphibole  asbestos  is  of  less 
density,  contains  only  about  5  percent  of  chemically  combined  water,  and 
on  account  of  its  very  brittle  fiber  is  not  capable  of  being  spun;  the  color 
is  gray-white  to  pink.  It  occurs  in  commerce  chiefly  in  the  powdered 
form,  and  is  used  in  the  manufacture  of  heat-insulating  materials.  Chryso- 
tile can  only  withstand  a  temperature  of  800°  to  500°  C.  without  loss  in 
strength,  but  amphibole  may  be  heated  to  1000°  to  1200°  C.  without 
essential  alteration.  Canadian  asbestos  is  the  most  valuable  as  a  source 
for  textile  purposes,  as  it  yields  a  curly  fiber  easily  spun  into  threads. 


Fig.  19. — Fiberised  Asbestos  ready  for  Market. 


The  length  of  the  fiber  varies  with  the  thickness  of  the  rock,  and  this  runs 
from  a  fraction  of  an  inch  up  to  about  4|  inches  (see  Figs.  18  and  19). 
Some  Italian  varieties  are  said  to  reach  the  exceptional  length  of  5  to  6  ft., 
but  are  harsh  and  brittle.  The  serpentine  asbestos  usually  occurs  in 
rather  narrow  veins  and  yields  fibers  of  but  2  to  3  ins.  in  length. 

3.  Grading  of  Asbestos, — Asbestos  fiber  is  usually  graded  into  three 
quahties  according  to  the  length  of  staple;  Grade  No.  1  is  valuable  for 
spinning;  while  No.  2  and  No.  3  are  used  for  making  mill-board  or  insu- 
lating materials.  The  different  grades  of  fiber  are  separated  by  shaker 
machines  and  air  blowers. 

Asbestos  fiber  is  divided  into  four  distinct  groups:  (a)  Cross  fiber, 
which  has  the  greatest  commercial  importance,  occurs  in  distinct  veins 
extending  from  wall  to  wall  of  the  serpentine  rock.  The  fibers  vary  in 
length  from  a  fraction  of  an  inch  to  about  2  ins.     (b)  Slip  fiber  runs  parallel 


GRADING  OF  ASBESTOS  31 

with  the  fracture  planes  produced  by  the  crushing  and  shearing  of  the  rocks. 
This  fiber  is  not  as  well  adapted  as  the  foregoing  to  spinning  purposes, 
(c)  Massfiher,as  the  name  suggests, does  not  occur  in  fissures,but  in  masses. 
The  conditions  which  produce  mass  fiber  are  essentially  different  from 
those  which  produce  cross  and  slip  fibers,  and  when  mass  fiber  is  found 
it  is  rarely  that  the  other  forms  occur  in  the  same  rock,  (d)  Shear  fiber 
is  made  up  of  cross  fiber  that  has  been  sheared  by  a  subsequent  movement 
of  the  rocks.  These  fibers  are  found  lying  parallel  with  the  fracture  planes, 
but  evidently  altered  in  their  direction  after  formation.  The  shear  fiber 
is  equal  in  strength,  fineness  and  flexibility  to  the  best  cross  fiber,  and  may 
sometimes  be  found  as  long  as  6  ins. 

There  can  be  little  doubt  that  there  is  a  definite  relation  between  the 
softness  of  the  asbestos  fiber  and  the  quantity  of  water  of  constitution 
it  contains;  14.38  percent  water  has  been  found  in  very  silky  fiber,  while 
a  harsh,  brittle  sample  gave  only  11.7  percent.  This  will  explain  the 
extreme  brittleness  of  the  amphibole  fiber,  some  samples  of  which  contain 
only  5.45  percent  water.  The  effect  of  high  temperatures  on  very  soft 
fiber  also  demonstrates  this  fact.  When  part  of  the  combined  water  has 
been  driven  off  by  excessive  heat,  the  fiber  loses  its  flexibility  a^d  becomes 
harsh  and  brittle;  and  the  variations  in  strength  and  silkiness  in  various 
deposits  of  the  mineral  are  best  explained  by  assuming  that  the  water 
content  was  originally  nearly  the  same  in  all  cases,  and  that  the  movement 
of  associated  rocks  or  the  injection  of  molten  rock  has  furnished  sufficient 
heat  to  drive  off  part  of  the  water. 

The  world's  consumption  of  asbestos  (1912)  was  about  100,000  tons,  of 
which  about  75,000  tons  came  from  Canada.  In  1918  the  production  of 
Canadian  asbestos  amounted  to  143,743  tons,  and  in  1920  to  174,521  tons. 
Asbestos  produced  in  the  United  States  in  1918  amounted  to  only  800 
tons.  About  50,000  tons  of  short-fiber  asbestos  mill-board  and  paper  are 
used  each  year  in  building  construction. 

It  was  formerly  claimed  that  Canadian  asbestos  was  inferior  to  that 
from  Italy,  and  that  it  was  also  a  different  species  of  mineral.  This, 
however,  has  long  been  proved  to  be  erroneous,  and  the  identity  of  the 
two  may  be  seen  by  reference  to  their  chemical  analysis.  Up  to  about 
1875,  nearly  all  the  commercial  asbestos  came  from  Italy,  but  the  cost 
of  producing  it,  due  to  the  local  difficulties  in  mining,  made  it  too  costly 
for  general  use ;  a  considerable  quantity,  however,  still  comes  on  the  mar- 
ket from  this  source.  The  Italian  asbestos  is  mostly  amphibole  and  is 
not  as  valuable  as  the  chrysotile  variety.  The  Canadian  supplies  are 
derived  from  quarries  in  the  neighborhood  of  Quebec.  The  deposits 
occur  in  a  narrow  zone  of  serpentine  rocks  extending  from  about  40  miles 
south  of  Quebec  to  a  point  within  the  United  States.  Asbestos  also 
occurs  in  many  other  parts  of  the  world,  though  not  of  the  proper  quality 


32 


ASBESTOS  AS  A  TEXTILE  FIBER 


to  make  it  commercially  useful.  It  Is  found  In  the  vicinity  of  Port  Bag, 
Newfoundland,  but  the  locality  so  far  is  very  inaccessible.  It  also  occurs 
in  various  parts  of  the  United  States,  in  Russia,  Siberia,  Finland,  Cyprus, 
Queensland,  South  Australia,  New  South  Wales,  New  Zealand,  Rhodesia 
and   China.     A   lavender-blue   variety   which   is   obtained   from   South 

Africa  is  said  to  possess  great  strength 
and  may  in  time  compete  with  the 
Canadian  variety.  A  rather  recent  im- 
portant field  of  asbestos  is  in  western 
Spitzbergcn.  It  is  being  quite  exten- 
sively operated  and  yields  a  highly 
fibrous,  pure  amphiliole  asbestos. 

4.  Asbestos  Yams  and  Fabrics. — 
In  general  the  fibers  of  asbestos  are 
straight  and  glassy  in  structure  and 
are  difficult  to  spin  into  a  coherent 
thread.  In  order  to  enhance  its  spin- 
ning qualities  it  is  mixed  with  a  little 
cotton  or  linen,  the  latter  fiber  being 
subsequently  destroyed  by  heating 
the  woven  fabric  to  incandescence. 
By  improved  methods  of  handling, 
however,  it  is  now  possible  to  spin 
asbestos  directly  without  admixture 
with  cotton.  The  asbestos  rock  is 
first  run  through  a  crusher  where  it  is 
fiberised  (see  Figs.  20  and  21).  By 
the  use  of  special  machinery  it  is  then 
separated  into  long  and  short  fiber;  the 
latter  is  utilised  for  the  manufacture 
of  mill-board  and  asbestos  paper,  while 
the  former  is  further  processed  by 
carding  and  spinning  to  make  a  twist- 
ed yarn. 

The  numbering  of  asbestos  yarn 
is  based  on  the  number  of  lengths  of 
100  yds.  that  weigh  1  lb, ;  thus  No.  2  yarn  indicates  that  200  yards  weigh 
1  lb.  As  single  yarns  lack  uniformity,  all  asbestos  yarns  come  into  the 
market  as  ply  yarns,  up  to  6  or  8  threads.  Summers  states  that  asbestos 
yarn  can  be  spun  to  weigh  less  than  an  ounce  to  a  length  of  100  yds.  and 
fine  asbestos  cloth  can  be  made  weighing  only  a  few  ounces  to  the  square 
yard.  Such  fabrics,  however,  are  curiosities  rather  than  commercial 
articles.     The  asbestos  yarns  and  fabrics  appearing  on  the  market  would 


Fig.  20. — Rotary  Crusher  for  Asbestos. 
(Butter worth  &  Lowe.) 


ASBESTOS   YARNS   AND   FABRICS 


33 


be  classed  as  crude  and  coarse  in  quality  as  compared  with  ordinary  tex- 
tile fabrics.  For  special  purposes  a  fine  brass  wire  is  sometimes  twisted 
with  the  yarn. 

At  the  present  time  quite  a  variety  of  fabrics  are  manufactured  from 
asbestos  fiber,  and  the  high  quality  of  many  articles  appearing  on  the 
market  shows  that  the  art  of  manipulating  this  substance  has  reached  a 
high  degree  of  perfection.  On  account  of  its  incombustible  nature,  and 
as  it  is  a  very  poor  conductor  of  heat,  it  is  made  into  fabrics  in  which 
these  qualities  are  especially  desired.  Thus  it  is  frequently  manufactured 
into  gloves  and  aprons,  packing  for  steam-cylinders,  theatrical  curtains 
and  scenery,  lamp  wicks,  etc.    The  use  of  asbestos  in  lamp  wicks  was 


Fig.  21. — Cyclone  Fiberiser  for  Asbestos.     (Laurie.) 

known  to  the  ancients,  who  employed  it  for  the  wicks  of  the  perpetual 
lamps  in  their  temples,  and  it  was  also  used  as  a  shroud  for  the  cremation 
of  the  kings.  It  is  from  this  fact,  indeed,  that  it  received  its  name,  the 
word  "asbestos"  meaning  "unconsumed."  In  later  times  it  was  known 
as  "salamander  wool,"  being  known  by  this  term  in  China,  where  it  was 
used  as  early  as  1600  for  the  weaving  of  napkins.  It  was  also  said  to  be 
employed  for  napkins  on  account  of  being  readily  cleansed,  it  only  being 
necessary  to  heat  the  fabric  in  a  flame  to  make  it  clean  again.  This 
statement,  however,  is  without  doubt  mythical,  together  with  a  similar 
one  regarding  the  asbestos  table  cloth  of  Charlemagne.  In  this  connection 
it  may  be  noted  that  there  is  considerable  misconception  as  to  the  effect 
of  high  temperature  on  asbestos.  It  is  true  that  asbestos  is  infusible 
except  at  very  high  temperatures,  and  also  that  it  is  perfectly  non-com- 
bustible and  non-inflammable;  nevertheless,  it  requires  only  a  moderate 


34 


ASBESTOS  AS  A   TEXTILE   FIBER 


degree  of  heat  (dull  redness,  for  example,  in  a  crucible),  to  entirely  destroy 
the  flexibility  of  the  fiber  and  to  render  it  so  brittle  that  it  may  be  easily 
crumbled  to  a  powder.  This  is  due  to  the  fact  that  the  heat  drives  off 
the  water  of  hydration  from  the  asbestos,  and  in  this  state  the  fibrous 
structure  easily  breaks  down. 

At  the  present  time  one  of  the  principal  uses  of  asbestos  yarns  is  in  the 
manufacture  of  cloth  for  the  lining  of  brake  bands  for  autom.obiles. 
Asbestos  cloth  is  also  used  (juite  extensively  in  a  numlier  of  chemical 
operations,  especially  for  the  {.Itering  of  acids  or  other  corrosive  liquids. 

In  some  cases  asbestos  is  spun  directly  around  a  copper  wire  for  pur- 
poses of  insulation.     Asbestos,  in  general,  is  not  dyed,  and  does  not  undergo 


Fig.  22. — Spool  of  Asbestos  Yarn.     (Johrs-Manvillc  Co.) 

any  chemical  processes  or  modes  of  treatment.  When  it  is  desirable  to 
dye  it  the  various  substantive  dyes  maj^  be  used  with  good  effect,  or  the 
color  may  be  applied  by  mordanting  with  albumen. 

Owing  to  the  extending  use  of  asl)estos  yarns  they  are  now  made  in 
quite  a  variety  of  sizes  and  composition.  The  commercial  j^arns  in  com- 
mon use  range  from  400  yds.  to  4000  yds.  to  the  pound  single-ply,  and 
may  consist  of  pure  asbestos  fiber  or  varying  mixtures  with,  cotton,  accord- 
ing to  specification.  A  single  yarn  running  1000  yds.  to  the  pound  will 
about  compare  in  size  to  a  4's  cotton  yarn.  Most  asbestos  fabrics  are 
made  from  2-ply  yarn  having  a  small  percentage  of  cotton  to  give  them 
additional  strength;  this  is  especially  true  of  cloth  for  theater  curtains 
and  the  like.  For  the  manufacture  of  automobile  brake  bands,  yarns  of 
pure  asbestos  twisted  with  wire  are  used. 


PROPERTIES   OF  ASBESTOS   TEXTILES 


35 


Asbestos  fabric  is  largely  used  for  packing  joints  and  glands  in  high- 
pressure  steam  engines,  for  which  purpose  the  fabric  is  usually  a  com- 
bination of  asbestos  yarn  and  metallic  wire.  The  use  of  asbestos  cloth 
of  this  character  is  very  extensive,  and  is  becoming  more  and  more  essential 
in  engineering  practice.  Asbestos  cloth  is  also  used  as  clothing  for  furnace 
men  in  the  metallurgical  industries,  it  being  the  only  material  for  this 
purpose  that  is  sufficiently  flexible  and  fire-resistant  and  at  the  same  time 
serves  as  a  heat  insulator.  The  fabric  used  for  fireproof  curtains  for 
theaters  is  woven  of  asbestos  and  wire  yarns.  The  manufacture  of  this 
cloth  is  now  carried  out  on  quite  an  extensive  scale,  as  it  is  required  by 
practically  every  theater  in  modern  cities.  Asbestos  cloth  is  also  used 
for  wall  linings  in  theaters  and  in  the  making  of  various  forms  of  theatrical 
scenery.  Asbestos  fabric  has  also  been  used  in  the  making  of  a  form  of 
artificial  leather  that  closely  resembles  the  natural  product  in  appearance 
and  characteristics,  but  is  waterproof  and  fireproof.  It  is  known  in  trade 
as  "Dellerite"  and  "Bestorite."  It  is  a  combination  of  asbestos  fiber 
and  vulcanised  rubber  worked  together  under  enormous  pressure. 

5.  Properties  of  Asbestos  Textiles. — Asbestos  itself  is  not  as  good  a 
non-conductor  of  heat  as  is  generally  supposed.  Its  non-conducting 
properties  are  more  due  to  the  fact  that  it  is  of  a  fibrous  character  and 
may  be  teased  out  into  a  fluffy  mass,  which  like  similar  masses  of  wool 
or  cotton  enclose  numerous  air-spaces.  Asbestos  itself  in  the  form  of  a 
compact  board  is  a  rather  poor  non-conductor;  it  is  only  when  it  is  made 
into  a  mass  possessing  a  fibro-cellular  structure  capable  of  occluding  con- 
siderable air  that  it  becomes  a  good  non-conductor.  Professor  Ordway 
(Eng.  ayid  Mining  Journal,  1890,  p.  650)  made  a  series  of  tests  relating  to 
the  comparative  values  of  different  fibers  as  non-conductors  of  heat. 
His  results  are  summed  up  as  follows:  A  mass  of  the  non-conducting 
material  1  in.  thick  was  placed  on  a  flat  surface  of  iron  kept  heated  to 
310°  F. ;  the  amount  of  heat  transmitted  per  hour  through  the  non-con- 
ductor was  measured  in  pounds  of  water  heated  10°  F.,  the  unit  of  area 
being  1  sq.  ft.  of  covering: 


Substance. 

Pounds  of  Water 
Heated  at  10°  F. 

Solid  Matter  in 

1  Sq.  Ft.  1  In. 

Thick,  Parts  in  1000. 

Air  Occluded, 
Parts  in  1000. 

Loose  wool 

8.1 
9.6 
10.4 
10.3  . 
49.0 
48.0 

56 
50 
20 
185 
81 
0 

944 

Goose  feathers 

Carded  cotton 

Hair  felt . 

950 
980 

815 

Fine  asbestos 

919 

Air  alone 

1000 

36 


ASBESTOS   AS  A   TEXTILE   FIBER 


Strong  sulfuric  acid  exerts  a  slight  solvent  action  on  asbestos.  Treat- 
ment with  sulfuric  acid  (80  percent)  according  to  Heermann  and  Sommers, 
shows  the  following  degrees  of  solubility  with  different  varieties  of 
asbestos:  Solubility, 

Percent. 

African  Blue  Asbestos 2.1 

South  African  White  Asbestos 12.3 

Russian  Ural  Asbestos 2.4 

Canadian  Asbestos 8.3 

German  Asbestos  (needle) .     0.9 


Fig.  23. — Typical  Cloth  Woven  from  Asbestos  Yarn.     (Johns-Manville  Co.) 

These  figures  represent  the  mean  values  of  several  determinations, 
and  it  is  to  be  observed  that  not  only  do  considerable  differences  appear 
with  the  different  varieties,  but  there  is  also  a  considerable  variation 
among  different  samples  of  the  same  variety  of  asbestos.  It  would  seem 
that  the  degree  of  solubility  is  greater  with  increase  in  the  fineness  of  the 
fibers  of  the  sample. 

Owing  to  this  solubility  of  asbestos  in  strong  sulfuric  acid  it  is  apparent 
that  determinations  of  mixtures  of  asbestos  and  cotton  fibers  cannot  be 
accurately  made  by  destroying  the  cotton  with  this  acid.  The  effect  of 
the  degree  of  fineness  of  the  fibers  on  the  amount  dissolved  by  the  sulfuric 
acid  is  shown  by  the  following  figures  taken  in  connection  with  the  pre- 
ceding ones:  Solubility, 

Percent. 

African  Blue  Asbestos,  coarse 1.6 

South  African  White  Asbestos,  fine  fibers 23 . 8 

Russian  Ural  Asbestos,  fine  fibers 6.3 

Canadian  Asbestos,  fine  fibers 17. 2 

German  Asbestos,  powdered 3.7 


PROPERTIES   OF   ASBESTOS   TEXTILES 


37 


It  will  be  seen  that  very  large  variations  occur,  depending  on  the  fineness 
of  the  fibers. 

Even  treatment  with  more  dilute  solutions  of  sulfuric  acid  show  consid- 
erable effect  on  asbestos.  The  foUowing  figures  show  the  amounts  dis- 
solved by  treatment  for  forty-eight  hours  with  a  cold  ^-normal  solution  of 


Fig.  24. — Gloves  made  from  Asbestos  Fabric.     (Johns-Manville  Co.) 

sulfuric  acid;   the  asbestos  in  all  cases  not  being  very  finely  divided  into 
fibers : 

Solubility, 
Percent. 

African  Blue  Asbestos 3.1 

South  African  White  Asbestos 39 . 6 

Russian  Ural  Asbestos 13 . 6 

Canadian  Asbestos 19 . 4 

German  Asbestos 1.5 

Treatment  of  asbestos  with  copper  oxide-ammonia  solution  shows  no 
loss  in  weight,  according  to  Heermann  and  Sommers,  and  consequently 
this  solution  may  be  employed  for  determining  the  amount  of  cotton  pres- 
ent in  the  sample  of  the  mixed  fibers.  The  material  should  be  first  washed 
with  an  alcohol-ether  mixture  to  remove  waxy  substances,  then  teased  out 
so  as  to  give  a  loose  fibrous  mass  and  finally  treated  with  a  cold  freshly 
prepared  solution  of  copper  oxide-ammonia  with  a  high  copper  content. 


CHAPTER  III 
WOOL:  ITS  ORIGIN  AND  CLASSIFICATION 

1.  The  Sheep. — The  woolly,  hairlike  covering  of  the  sheep  forms  the 
most  important  and  the  most  typical  of  the  textile  fibers  which  arc  obtained 
from  the  skin  tissues  of  different  animals.  The  hairy  coverings  of  a  large 
number  of  animals  are  employed  to  a  greater  or  lesser  extent  as  raw 
materials  for  the  manufacture  of  different  textile  products,  but  those  of  the 
various  species  of  sheep  make  up  the  great  bulk  of  the  fibers  which  possess 
any  considerable  technical  importance. 

Hairs,  derived  from  whatever  species  of  animals,  have  very  much  in 
common  as  to  their  general  physical  and  chemical  properties;  they  are 
also  similar  with  respect  to  their  physiological  origin  and  growth.  An 
animal  hair  consists  of  the  root  situated  in  a  depression  of  the  skin  (hair 
follicle)  and  the  shaft,  or  hair  proper.  In  the  typical  hair  three  sharply 
defined  tissues  are  present :  the  epidermis,  or  cuticular  layer,  the  cortex,  or 
fiber  layer,  and  the  tnedulla,  or  pith.  Hairs  are  distinguished  according  to 
their  length,  stiffness,  etc.,  as  bristles,  bristle  hairs,  beard  hairs,  and  wool.  The 
long,  stiff,  elastic  hairs  of  the  hog  are  typical  bristles.  Bristle  hairs  are 
short,  straight,  stiff  hairs  with  a  medulla,  such  as  the  body  hairs  of  the  horse. 
Beard  hairs  arc  the  long,  straight,  or  slightly  wavy,  regularl}^  distributed 
hairs  (generally  with  a  medulla)  which  give  the  pelts  of  various  animals 
their  value.  Human  hair,  and  the  hair  from  the  manes  and  tails  of  horses, 
also  belong  to  this  class.     Wool  hairs  are  soft  and  flexible. 

At  what  point  an  animal  fiber  ceases  to  be  a  hair  and  becomes  wool  is 
impossible  to  determine,  because  the  one  by  imperceptible  gradations 
merges  into  the  other,  so  that  a  continuous  series  can  be  formed  from  the 
finest  and  softest  merino  to  the  rigid  bristles  of  the  wild  boar.  Thus  the 
fine,  soft  wool  of  the  Australian  merino  merges  into  the  cross-bred  of  New 
Zealand ;  the  cross-bred  of  New  Zealand  merges  into  the  long  English  and 
luster  wool,  which  in  turn  merges  into  alpaca  and  mohair  materials  with 
clearly  marked  but  undeveloped  scale  structure.  Again,  such  animals  as 
the  camel  and  the  cashmere  goat  yield  fibers  which  it  would  perhaps  be 
difficult  to  classify  rigidly  as  either  wool  or  hair.^ 

The  hairs  of  different  animals  vary  much  in  the  detail  of  their  special 
characteristics,  and  also  with  regard  to  their  adaptability  for  use  in  the 

^  See  Barker,  Encyl.  Brit. 
38 


DIFFERENT   CLASSES   OF  HAIR  FIBERS 


39 


textile  industry;  and  the  wool  of  the  sheep  appears  to  exhibit  in  the 
highest  degree  those  specific  properties  which  make  the  most  suitable 
textile  fiber.  These  properties  may  be  enumerated  as  being :  (a)  SuflEicient 
length,  strength,  and  elasticity,  together  with  certain  surface  cohesion, 
to  enable  several  fibers  to  be  twisted  or  spun  together  so  as  to  form  a 
coherent  and  continuous  thread  or  yarn;  (6)  the  power  of  absorbing  color- 
ing matters  from  solution  and  becoming  dyed  thereby,  and  also  the  prop- 
erty of  becoming  decolorised  or  bleached  when  treated  with  suitable 
chemical  agents;  (c)  in  addition  to  these  qualities,  which  they  have  in 
common  with  almost  any  textile  fiber,  wool  fibers  also  possess  the  quality 
of  becoming  felted  or  matted  together.     This  property  is  a  most  valuable 


Fig.  25  — Cotswold  Ram  of  U.  8.  A. 


one,  as  it  adapts  wool  to  a  large  number  of  uses  to  which  other  fibers  are 
unsuited. 

Silk  is  also  a  member  of  the  general  group  of  animal  fibers  and  though 
it  possesses  certain  general  chemical  characteristics  in  common  with  wool 
and  hair,  yet  it  has  an  entirely  different  physiological  origin,  being  a 
filament  of  animal  tissue  excreted  by  a  certain  species  of  caterpillar,  and 
hence  is  totally  different  from  wool  in  its  physical  properties.  There  is 
also  a  distinct  chemical  difference  in  wool  and  silk.  The  former  contains 
sulfur  as  an  essential  constituent,  while  the  latter  contains  no  sulfur  in  its 
composition. 

2.  Different  Classes  of  Hair  Fibers. — Wool  may  be  specifically  desig- 
nated as  a  variety  of  hair  growing  on  certain  species  of  mammalia,  such 
as  sheep,  goats,  etc.  The  unmodified  term  "  wool  "  has  special  reference 
to  the  product  obtained  from  the  different  varieties  of  sheep.     Cashmere, 


40  WOOL:    ITS  ORIGIN   AND   CLASSIFICATION 

mohair,  and  alpaca  are  the  products  obtained  from  the  thibet,  angora, 
and  llama  goats,  respectively.  Fur  is  also  a  modified  form  of  hair,  but 
differs  from  wool  in  many  of  its  physical  properties,  and  is  not  adapted 
for  use  in  the  manufacture  of  spun  textiles.  It  is,  however,  largely  em- 
ployed for  the  making  of  hat  felts.  The  cross-section  of  wool  is  almost 
circular,  while  that  of  fur  is  quite  elliptical.  The  fur  of  the  hare,  rabbit, 
and  cat  is  occasionallj^  mixed  with  cotton,  wool,  or  waste  silk  and  spun 
into  yarns.  Such  yarns  are  principally  used  for  the  weaving  of  certain 
kinds  of  velvets. 

Hohnel  states  that  it  is  usual  to  distinguish  hairs  as  down  or  wool- 
hair,  beard-hair,  bristle-hair,  brush-hair  and  quill-hair.  The  differences 
between  these  varieties,  however,  depend  less  on  actual  anatomical  rela- 
tions than  on  external  properties,  such  as  strength,  rigidity,  thickness, 
length,  form,  etc.  In  order  to  make  this  clear,  let  us  take  an  example: 
The  beard-hairs  of  rabbit  skin  in  the  lower  part  cannot  be  distinguished 
from  the  true  wool-hairs,  whereas  their  points  have  the  same  structure 
as  bristles.  Furthermore,  the  fine  beard-hair  of  Newcastle  sheep  is  con- 
structed just  like  the  wool  of  other  thoroughbred  sheep;  while  again,  the  fur 
of  the  hare,  beaver,  and  many  other  "  pelt  animals  "  possesses  the  same 
typical  structure  as  the  true  beard-hairs  of  thoroughbred  sheep.  From 
this  it  may  be  seen  that  the  different  varieties  of  hair  may  be  more  easily 
characterised  by  their  external  marks  than  by  their  comparative  anatomy. 
Down  or  wool-hairs  are  thin  and  white,  generally  not  stiff,  but  curly. 
The  beard-hairs  are  more  straight  and  stiff;  have  sharp  points,  and  are 
generally  thicker  and  darker  than  the  wool  of  the  same  animal.  They  are 
also  longer  than  the  latter.  Beard-hairs  and  wool  together  form  the 
fleece.  By  bristle-hairs  is  understood  short  pointed  hairs,  such  as  generally 
occur  on  the  less  hairy  parts  of  the  animals ;  for  instance,  at  the  ends  of  the 
limbs  and  parts  of  the  head.  Brush-hairs  are  generally  solid  and  possess 
only  a  slight  marrow;  furthermore,  they  are  more  cylindrical  in  form. 
Quill-hairs  are  more  conical  in  shape,  and  are  generally  either  hollow  or 
possess  a  well-developed  marrow. 

3.  Wool-bearing  Animals. — The  wool-bearing  animals  all  belong  to  the 
order  Ruminantia,  which  includes  those  animals  that  chew  their  cud  or 
ruminate.  The  principal  members  of  this  order  are  sheep,  goats,  and 
camels.  The  sheep  belong  to  the  class  Ovidce,  and  occurs  in  a  number 
of  species  which  vary  considerably  in  form  and  geographical  distribution, 
as  well  as  in  the  character  of  the  wool  they  produce. 

The  fleeces  of  certain  primitive  breeds  of  sheep  have  been  examined, 
including  Marco  Polo's  sheep,  Ovis  ammon  poli.  There  are  two  coats— 
a  summer  and  a  winter  one.  The  former  is  entirely  of  hair,  more  or  less 
pigmented.  The  latter  is  double,  an  outer  coat  of  hair  similar  to  the 
summer  coat,  and  an  inner  coat  of  fine  curled  wool.     In  the  case  of 


CLASSIFICATION   OF  SHEEP 


41 


0.  orientalis  the  fibers  of  the  inner  (winter)  coat  do  not  form  a  much 
entangled  mass  as  in  the  other  cases,  but  natural  locks  very  similar  in 
form  to  those  of  modern  commercial  wool.  The  two  kinds  of  fibers, 
wool  and  hair,  in  these  primitive  fleeces  are  quite  distinct,  and  no  sort 
or  grade  of  intermediate  fiber  was  found.  It  is  inferred  that  fibers  of 
intermediate  character  found  in  semi-modern  fleeces  cannot  be  transitional 
forms,  and  the  question  whether  hair  and  wool  are  different  in  origin  and 
development  or  whether  they  result  from  divergent  development  of  a 
common  type  of  fiber  of  intermediate  character  cannot  yet  be  answered.^ 


Fig.  26. — Lincoln  Ewe  (American). 


4.  Classification  of  Sheep.— Broadly  considered,  naturalists  divide  the 
sheep  into  three  different  classes:- 

(a)  Ovis  aries,  commonly  known  as  the  domestic  sheep,  and  cultivated  more  of 
less  in  every  country  of  the  world. 

(b)  Ovis  musmon,  occurring  native  in  the  European  and  African  countries  bordering 
on  the  Mediterranean  Sea.  This  sheep  is  also  known  as  the  moufflon  and  is  found  par- 
ticularly in  the  islands  of  the  Mediterranean  Sea.  It  is  smaller  than  the  argali,  which 
is  described  below.  The  fleece  is  of  a  short,  brownish,  furry  fiber,  though  there  is 
also  an  undercoat  of  short,  fine  wool  of  a  gray  color. 

(c)  Oins  ammon,  which  includes  the  wild  or  moimtain  sheep  (argali)  to  be  found 
in  Asia  and  America.  The  big-horn  sheep  of  the  Rocky  Mountains  belongs  to  this 
class.     The  argali  sheep  are  large  animals  as  compared  with  the  ordinary  domestic 

1  Crew,  Ann.  Appl.  Biol,  1921,  p.  164. 

"  Barker  states  that  in  the  absence  of  more  definite  records  it  is  questionable 
whether  the  many  types  of  sheep  of  the  present  day  are  the  progeny  of  one  common 
ancestor  or  have  arisen  independently.  It  is  probable  that  in  the  remote  past  only 
one  type  existed,  and  that  modifications  of  this  type,  due  to  varying  environment  and 
selection  in  breeding,  have  formed  the  basis  of  all  our  modern  sheep. 


42 


WOOL:     ITS   ORIGIN   AND   CLASSIFICATION 


sheep.  The  fleece  in  summer  is  of  a  furry  character  with  a  reddish  brown  color;  in 
winter  distinct  hair  of  a  brownish  gray  color  is  developed,  with  an  undercoat  of  white 
wool. 

Bowman  suggests  the  classification  of  sheep  into  the  following  three 
divisions,  based  on  the  length  of  the  average  fibers : 

(1)  Short,  fine,  pure-wooled  sheep,  such  as  the  merino  or  Southdown. 

(2)  Medium-staple   and    cross-bred   sheej),    such   as   those    from    which    the   fine 
coml)ing;  Australian  wools  are  obtained. 

(3)  Long-wooled,  bright-haired  sheep,  such  as  Leicester  and  Lincoln  breeds. 


Fig.  27. — Southdown  Ram  (American). 


A  more  detailed  classification  tha 
divides  the  sheep  into  thirty-two  var 

1.  Spanish,  or  merino  sheep   {Oiis  his- 

panioe) . 

2.  Common  sheep  {0ms  rusiiciis). 

3.  Cretan  sheep  (0ns  sirepsiceros) . 

4.  Crimean  sheep  (0ns  longicaudatus.) 

5.  Hooniah,    or    black-faced    sheep    of 

Thibet. 

6.  Cago,  or  tame  sheep  of  Cabul  (Ovis 

cagia) . 

7.  Nepal  sheep  (Oins  selingia). 

8.  Curumbar,  or  Mysore  sheep. 

9.  Garar,  or  Indian  sheep 

10.  Dukhun,  or  Deccan  sheep. 

1 1 .  Morvant  de  la  Chine,  or  Chinese  sheep . 

12.  Shaymbliar,  or  Mysore  sheep. 

13.  Broad-tailed  sheep  (Oiis  laticaudatus) . 

14.  Many-horned  sheep  (Ovis  polyceratus) . 

15.  Pucha,  or  Hindoostan  dumba  sheep. 

16.  Tartar y  sheep. 


-  the  above  is  given  by  Archer,  who 
ieties : 
17.  Javanese  sheep. 
IS.  Barwall  sheep  (Ovis  harwal). 

19.  Short-tailed  sheep  of  northern  Russia 

(Ovis  brencmidatus) . 

20.  Smooth-haired  sheep  (Oi>is  ethiojna). 

21.  African  sheep  (Ovis  grienensis). 

22.  Guinea  sheep    (Ovis  ammon  guineen- 

sis) . 

23.  Zeylan  sheep. 
24    Fezzan  sheep. 

25.  Congo  sheep  (Oiis  aries  congensis). 

26.  Angola  sheep  (Oiis  aries  angolensis) . 

27.  Yenu,   or  goitered  sheep    (Ovis  aries 

steatiniora) . 

28.  Madagascar  sheep. 

29.  Bearded  sheep  of  west  Africa. 

30.  Morocco  sheep  (Oris  aries  numidioc). 

31.  West  Indian  sheep  of  Jamaica. 

32.  Brazilian  sheep. 


THE  DOMESTIC  SHEEP 


43 


These  represent  the  naturally  occurring  classes  of  sheep  in  the  different 
countries;  of  course,  a  large  number  have  been  emigrated  and  domesticated 
in  other  countries  than  those  in  which  they  had  their  origin,  which  has 
given  rise  to  several  subvarieties.  Then,  too,  new  varieties  have  been 
formed  by  cross-breeding  and  intermixing,  which  has  brought  about  a 
considerable  variation  in  the  type.  The  latter  is  also  influenced  very 
largely  by  climatic  conditions,  geographical  environment,  and  character 
of  pasturage. 

5.  The  Domestic  Sheep. — The  domestic  sheep  is  the  most  important 
of  these  classes.  It  yields  by  far  the  greater  portion  of  the  wool  of  com- 
merce. Other  varieties,  such  as  the  Hungarian  sheep,  the  Zigaja  sheep, 
the  Moorland  sheep,  etc.,  yield  an  inferior  fleece  consisting  of  a  mixture 


Fig.  28. — Merino  Ram  (American). 


of  wool  and  beard-hairs.  The  domestic  sheep  can  hardly  be  said  to  be 
indigenous  to  any  one  country,  for  it  appears  to  have  been  cultivated  by 
the  earliest  peoples  in  history,  and  it  has  spread  over  the  entire  face  of  the 
globe  with  the  gradual  extension  of  civilisation  itself.  The  first  actual 
mention  of  sheep  in  England  appears  in  a  document  of  the  year  712, 
where  the  price  of  the  animal  is  fixed  at  one  shilling  until  a  fortnight  after 
Easter. 

Different  conditions  of  climate  and  soil,  of  pasturage  and  cultivation, 
appear  to  exert  a  considerable  influence  on  the  variety  of  the  sheep  and 
on  the  character  of  the  wool  it  eventually  produces.  Variations  are  also 
produced  by  cross-breeding  and  intermixing,  and  the  nature  of  the  fiber 
has  been  much  altered  and  improved  by  careful  selection  in  breeding  and 
genealogical  development. 


44  WOOL:    ITS   ORIGIN  AND   CLASSIFICATION 

The  following  diagram  shows  the  general  pedigree  of  the  domestic  sheep ; 


Merino 


Mountain 


Saxony  Merino 


Spanish  Merino 


English 
Long  Wool 


Australian 
Merino 


English 
Southdown 


Buenos  Ayres 
Merino 


English 
Half-breed 


Scotch 

Black 

Faced 


Mixed  Breeds 


Carpet 
Wool 


I     Crof^K-brcd 

Barker  gives  a  convenient  trade  classification  of  British  sheep  as 
follows : 

(1)  Long  Wool  Breeds. — Lincoln,  Leicester,  Border  Leicester,  Cotswold,  Romney 
Marsh,   \\'ensleydale,   Devon.     These  wools  are  characterised  by  length  and  luster, 

aiul  are  usually  remark- 
able for  strength  and 
soundness.  They  arc 
typical  worsted  materials, 
being  straight-fibered  and 
capable  of  conversion  into 
a  parallel  fibered  yarn  of 
marked  smoothness  and 
luster.  They  are  em- 
ployed mostly  for  the 
production  of  tiright  fab- 
rics which  are  durable  and 
possess  excellent  draping 
qualities. 

(2)  SJiort  Wool  Breeds. 
— Southdown,  Shropshire- 
down,  Hampshiredown, 
Oxforddown,Suffolkdown, 
Dorset,  Ryeland.  The 
main  feature  of  these 
wools  is  a  firm  and  clearly  defined  curliness  which  makes  them  particularly  suitable 
for  hosiery  yarns  where  fulness  and  softness  are  important.  The  fiber  is  usually  of 
good  color  and  fine  in  staple,  therefore  useful  for  light-weight  goods.  These  wools  are 
not  remarkable  for  strength  and  they  usually  do  not  felt  well.  They  are  employed 
considerably  in  woolen  fabrics  to  give  fulness  and  springiness. 

(3)  Mountain  Breeds. — Blackface,  Herdwick,  Cheviot,  Louk,  Dartmoor,  Exmoor, 
Penistone.  These  wools  are  usually  bred  with  less  care  and,  being  grown  under  more 
severe  climatic  conditions,  lack  brightness  and  are  irregular  in  fiber  and  staple.  Also, 


Fig.  29.— Scotch  Black-faced  Kam. 


GEOGRAPHICAL  DISTRIBUTION   OF  SHEEP  45 

differences  in  various  portions  of  the  fleece  are  more  marked  and  there  is  a  greater 
quantity  of  kemps;  hence,  these  wools  give  more  trouble  in  sorting  and  spinning  and 
also  in  dyeing.  The  fiber  is  usually  rough  and  wiry  and  poor  in  cohering  qualities, 
hence  spins  rather  poorly  and  is  harsh  in  handling.  They  are  used  for  lower -grade 
thick  yarns  for  both  woolen  and  worsted  types.  The  cheviot  wool  is  the  most 
important  of  tliis  class,  giving  its  name  to  a  Scotch  tweed  cloth. 

(4)  Highland  Breeds. — Short-tailed,  Welsh,  Irish.  These  wools  lack  character  and 
trueness.  With  the  exception  of  the  Irish  wool  (which  is  the  best  of  this  class)  they 
ire  irregular  in  staple,  thick  in  fiber  and  contain  much  kemps,  hence  spin  poorly  and 
give  much  waste.  They  are  only  suitable  for  thick  goods  of  low  quality,  and  are 
largely  used  for  flannels,  dress-goods  and  tweeds. 

6.  Geographical  Distribution  of  Sheep. — The  merino  sheep,  which 
yields  what  is  considered  to  be  the  finest  quahty  of  wool,  appears  to  have 
originated  in  Spain,  and  at  one  time  was  extensively  cultivated  by  the 
Moors.  The  sheep,  however,  certainly  was  a  domestic  animal  in  Britain 
long  before  the  period  of  the  Roman  occupation;  and  it  is  probable  that 
some  use  was  made  of  sheep-skins  and  wool.  But  the  Romans  established 
a  wool  factory  whence  the  occupying  army  was  supplied  with  clothing, 
and  the  value  of  the  manufacture  was  soon  recognised  by  the  Britons. 

The  Spanish  merino  sheep  consisted  of  two  chief  races:  (1)  The  short- 
legged  Nigretti  sheep,  later  known  as  Infantados,  with  pronounced  neck- 
folds  and  a  dewlap,  and  (2)  the  tall,  long-legged  Escurial  sheep.  The 
Saxon  Electoral  breed  is  a  derivative  of  the  latter  race,  while  the 
Austrian  Imperial  and  the  French  Rambouillet  breeds  are  derivatives 
of  the  former.  The  English  breeds  of  long-wool  or  luster-wool  sheep, 
including  the  Lincolns,  Leicesters,  and  Cotswolds,  yield  fleeces  consisting 
chiefly  of  beard-hairs. 

The  exportation  of  merino  sheep  from  Spain  was  long  guarded  against 
with  great  care,  no  one  being  allowed  to  take  a  live  merino  sheep  out  of 
the  kingdom  of  Spain  under  penalty  of  death.  Later,  however,  this  sheep 
was  brought  into  various  countries,  being  crossed  with  the  different  local 
breeds  with  very  beneficial  results.  A  German  derivative  of  the  Spanish 
merino  known  as  the  Saxony  Electoral  merino,  gives  perhaps  the  highest 
grade  of  fiber  known  in  Europe.  Australian  sheep  are  mostly  derived 
from  merino  and  other  high-class  stock  and  yield  a  wool  of  the  highest 
quality.  The  merino  has  been  cultivated  and  crossed  with  other  breeds 
throughout  the  various  parts  of  the  United  States,  and  this  country  has 
become  a  large  producer  of  middle-grade  wool.  Sheep  were  introduced 
at  Jamestown  in  Virginia  in  1609  and  in  1633  the  animals  were  first  brought 
to  Boston.  Ten  years  later  a  fulling  mill  was  erected  at  Rowley,  Mass. 
The  factory  woolen  industry,  however,  was  not  established  till  the  close 
of  the  eighteenth  century,  and  it  is  recorded  that  the  first  carding  machine 
put  into  operation  in  the  United  States  was  constructed  in  1794,  under  the 
supervision  of  John  and  Arthur  Schofield. 


46  WOOL:     ITS   ORIGIN   AND   CLASSIFICATION 

7.  Australian  Wools. — First  and  foremost  of  the  wool-producing 
countries  of  the  world  is  Australia,  and  although  it  possesses  no  indigenous 
breed  of  its  own,  it  can  be  stated  without  fear  of  contradiction  that  no 
country  has  been  so  successful  in  sheep  rearing  up  to  the  present  stage 
of  the  world's  history. 

The  effect  of  climate  upon  the  growth  of  wool  has  been  demonstrated 
very  effectively  in  this  country,  as  may  be  illustrated  from  the  following 
facts:  The  first  sheep  introduced  into  Australia  came  from  India,  and 
were  of  exceptionally  poor  quality.  They  possessed  a  coarse,  hairy  fleece, 
and  in  this  respect  resembled  goats,  rather  than  sheep;  but  under  the 
influence  of  the  country's  splendid  climate  and  pastures,  they  became  very 
much  changed  in  character,  so  much  so  that  in  the  course  of  a  few  years 
they  lost  all  their  hair-like  growth,  and  a  wool  of  respectable  quality  was 
produced. 

This  process  of  migration  proved  so  successful  that  Southdowns  and 
Leicesters  were  introduced  from  England,  with  very  marked  success. 
The  later  introduction  of  the  merino  sheep  to  Australia,  and  crossing  the 
breed  with  the  prevailing  sheep  of  the  colony,  gave  the  impetus  to  the 
development  of  the  industry,  which  henceforth  became  the  staple  trade 
of  Australasia.  The  millions  of  sheep  which  now  cover  the  pastures  of 
New  South  Wales,  Victoria,  Queensland,  New  Zealand,  and  Tasmania 
are  second  to  none  in  the  world,  some  even  rivaling  the  finest  Saxony. 
The  wool  is  fine  in  fiber  and  of  good  color,  and  besides  possessing  good 
spinning  properties,  it  is  in  great  demand  for  its  high  milling  or  felting 
value.  The  luster  cross-breds  that  are  now  produced  in  Australasia, 
and  especially  those  of  New  Zealand,  are  also  worthy  of  note.  As  a 
56's  quality^  for  worsted  serges,  this  wool  is  very  superior;  it  is  of  good 
length,  lustrous,  and  produces  a  good  yield. 

In  Australia  about  75  percent  of  the  wool  grown  is  merino  and  about 
25  percent  is  cross-bred,  and  the  tendency  is  for  the  cross-bred  production 
to  increase  somewhat,  owing  to  the  development  of  the  frozen  mutton 
trade,  as  the  large  cross-bred  sheep  yields  valuable  meat  while  the  merino 
does  not.  In  New  Zealand  the  tendency  is  for  cross-breds  to  supplant 
merinos  altogether,  and  at  the  present  time,  of  the  wool  grown  in  New 
Zealand,  only  about  5  percent  is  merino.  The  New  Zealand  cross-bred 
wool,  however,  is  unrivaled  in  strength,  soundness,  fineness,  softness,  luster 
and  color.  There  are  many  types  of  sheep  employed  in  crossing  and  in 
various  degrees,  consequently  a  large  range  of  qualities  of  wool  is 
produced. 

8.  European  Merino  Sheep. — The  merino  of  European  cultivation  is 

^  This  term  as  used  in  connection  with  qualities  of  wool,  means  that  the  fiber  is 
suitable  for  spinning  yarn  of  count  56.  For  definitions  and  comparisons  of  different 
sizes  see  Chapter  XXVIII. 


EUROPEAN    MERINO   SHEEP 


47 


of  high  standard  quahty,  but  the  supply  is  a  very  Hmited  one,  so  far  as 
exportation  is  concerned. 

Barker  gives  the  following  properties  of  the  different  types  of  merino 
wools  : 


Fine. 


Medium. 


Strong. 


Quality 

Length  of  staple,  ins 

Fineness,  ins 

Softness 

Color 

Waviness,  per  inch.. 
Impurities,  percent  . 
Appearance 

Uses 


70's  to  90's 

2f 

1/1600 

Very  soft 

Very  white 

26 

48  to  52 

Clearly  defined,  dense 

and  uniform 
Cashmeres,  Italians, 
worsted  coatings — 
the  short  fibers  into 
finest  woolens  and 
billiard  cloths 


60's  to  64's 
3^ 

1/1200 
Soft 
White 

20 

50  to  54 

Uniform,  bold  growth 

and  robust 
Worsted,  coatings, 
dress-goods  —  the 
short  fibers  into 
woolens,  army 
cloths 


58's 

4 

1/1000  and  below 

Fairly  soft 

Fairly  white 

16 

52  to  56 

Fairly  uniform,  open, 

not  distinct 
Cheaper  fabrics,  used 
for    blending    with 
cross-breds  and  for 
hosiery  yarns 


It  may  be  mentioned  that  all  merinos  are  of  Spanish  origin,  and  how- 
ever they  may  flourish  in  other  parts  of  the  world,  it  is  only  fair  to  state 
that  the  quality  of  the  wool  that  is  produced  in  Spain  has  not  been  excelled 
to  any  marked  degree. 

Historical  writers  tell  us  that  the  fleeces  of  the  original  Spanish  merinos 
were  either  wholly  or  partially  brown  or  black  in  color,  but  by  careful 
selection  and  breeding,  white  wools  were  eventually  produced.  The 
probability  of  this  statement  is  evidenced  by  the  fact  that  we  still  have 
naturally  colored  wools  produced,  both  in  Spain  and  other  parts  of  the 
world,  where  Spanish  sheep  have  been  inti'oduced  and  acclimatised. 
About  the  year  1723  the  Spanish  merino  was  introduced  into  Sweden,  but 
probably  on  account  of  the  colder  climate,  which  is  not  favorable  to  fine 
wool  growing,  it  did  not  flourish.  Shortly  after,  the  breed  was  introduced 
into  France,  but  not  being  kept  pure,  it  deteriorated  somewhat  in  quality. 
In  the  years  1765  and  1775  they  were  respectively  introduced  into  Germany 
and  Austria,  where  they  have  flourished  to  a  remarkable  extent. 

Special  mention  may  be  made  of  the  German  merinos,  which  by  careful 
attention  and  breeding,  especially  in  the  kingdom  of  Saxony,  have  closely 
rivaled  their  progenitors  of  Spain.  The  wool  has  a  fine  soft  handle,  and 
is  of  high  spinning  and  felting  value.  The  Austrian  merinos,  which  are 
sometimes  termed  the  Negretti  or  Infantado  breed,  produce  a  wool  that 
is  inferior  to  that  produced  by  their  German  neighbors.     It  is  usuallj'-  very 


48  WOOL:    ITS   ORIGIN   AND   CLASSIFICATION 

thick  in  the  fleece,  and  often  very  matted  or  tangled,  while  the  yolk  or 
grease  that  it  contains  is  so  stiff  as  to  render  washing  out  difficult,  but 
when  cleaned  it  is  fairly  fine  and  long. 

The  merino  sheep  was  introduced  into  England  about  the  year  1791, 
but  the  climate  of  the  country  was  not  compatible  with  the  demands  of  the 
breed,  and  in  consequence  the  quality  of  the  wool  could  not  be  preserved, 
although  much  advantage  was  gained  by  crossing  it  with  native  breeds. 
The  merino  sheep  was  introduced  into  Holland  and  Belgium  about  the 
year  1789,  but  it  has  not  acquired  the  same  standard  of  perfection  as  in 
Germany,  or  even  Austria. 

The  wools  of  Great  Britain  vary  from  short  to  long  and  are  divided  into 
two  classes  under  these  terms.  The  finest  British  wools  grown  are  the 
Southdown  wools  of  about  56's  quality,  while  the  coarsest  are  the  mountain 
wools  of  Scotland  and  Wales.  The  Lincoln  and  Leicester  wools  are 
renowned  throughout  the  world  as  the  finest  long  wools  grown.  They  have 
a  long,  wavy  staple  of  good  breadth,  which  is  indicative  of  trueness  of 
breeding.  They  possess  a  good  luster  and  are  particularly  valuable  for 
certain  fabrics.  The  southern  uplands  of  Scotland  are  among  the  best 
sheep  regions  in  the  British  Islands.  In  this  section  there  are  more 
sheep  per  acre  than  anywhere  else  in  the  world. 

Russia  produces  many  varieties  of  wool,  mostly  of  the  coarse,  hairy 
type.  The  Danube  provinces  produce  wool  mostly  from  the  Wallachian 
sheep;  it  is  of  a  fine,  soft  character,  l)ut  its  value  is  lessened  by  the  presence 
of  coarse  hairs.  It  is  mostly  manufactured  locally  for  cheap  apparel 
fabrics. 

Iceland  wool  is  of  low  quality  and  forms  a  species  of  down  at  the  base 
of  a  longer  hair  covering.  It  is  used  chiefly  for  rugs  and  blankets.  The 
wools  of  Norway,  Sweden  and  Denmark  are  rather  coarse  and  much 
mixed  with  strong  hair. 

9.  Sheep  of  the  United  States. — Various  classes  of  sheep  were  intro- 
duced into  the  United  States  in  colonial  times.  Since  their  introduction, 
such  developments  have  taken  place  that  sheep  farming  has  now  become 
one  of  the  important  industries.  At  the  present  time,  there  are  many  first- 
class  flocks  scattered  over  the  country  that  are  of  distinctly  merino  handle 
and  finish. 

Special  mention  may  be  made  of  the  Vermont  sheep,  which  are  notable 
for  the  heavy  weight  of  fleece  they  produce.  This  characteristic  has  been 
taken  advantage  of  by  some  Australian  breeders,  who,  by  crossing  the 
Vermont  with  their  own  breeds,  have  secured  good  results  in  the  weight 
of  the  fleeces  of  what  are  known  as  the  Australian- Vermont  cross-breds. 

The  State  of  Wyoming  produces  a  quality  of  wool  that  is  of  good  color, 
and  by  careful  selection  could  be  made  into  an  extremely  useful  class. 
The  wools  of  Texas  and  Arkansas,  although  of  fine  and  soft  handle,  are 


SOUTH   AMERICAN   WOOLS  49 

rather  tender  and  dirty.  The  States  of  Oregon,  Nevada  and  Ohio  also 
produce  their  quota  of  wool,  but  although  they  are  useful  qualities,  they 
are  inclined  to  be  tender  and  could  be  much  improved. 

The  United  States  can  use  all  of  the  wool  it  produces,  and  in  fact 
must  import  large  quantities  of  foreign  wools  to  supply  her  needs.  No 
country  in  the  world  surpasses  some  parts  of  the  United  States  as  a  field 
for  sheep  farming,  with  its  undulating  pasture  lands,  rich  in  the  finest 
herbage  and  abundance  of  water.  The  fact  that  sheep  can  be  fed  on  the 
green  parts  of  the  cotton  plant  and  the  cotton-seed  cake,  after  the  oil  is 
expressed,  has  been  taken  advantage  of  in  the  South,  and  there  can  be 
little  doubt  that  America  could  be  made  an  important  wool-producing 
country  in  all  qualities  that  can  be  required.^ 

10.  South  American  Wools. — The  majority  of  the  sheep  in  South 
America  are  the  offspring  of  Spanish  breeds,  which  were  introduced 
under  the  viceroyalty  of  Spain,  The  chief  breeds  are  the  Buenos  Ayres 
and  the  Montevideo  merinos.  The  wools  produced  from  these  sheep  are 
fine  in  fiber,  but  are  much  contaminated  with  burrs.  The  River  Platte 
cross-breds  are  similar,  in  many  respects,  to  those  of  New  Zealand,  and  are 
employed  for  similar  purposes.  Argentine  wool  is  known  as  B.  A.  (Buenos 
Ayres)  or  River  Platte.  Uruguayan  wool  is  known  as  M.  V.  (Monte 
Videan).  Owing  to  the  natural  pasturage  being  burry  and  seedy.  South 
American  wools  are  liable  to  contain  a  large  amount  of  vegetable  matter. 
The  M.  V.  wools  are  largely  of  the  merino  type,  and  vary  from  58's  to  64's 
in  quality.  They  give  a  good  yield  of  fiber  and  are  short  and  loose  in 
staple,  and  full  and  spongy  in  handle,  therefore  suitable  for  hosiery  and 
dress-goods  of  a  soft  nature.  They  are  also  used  largely  for  blending  with 
Australian  wools.  The  B.  A.  wools  are  light  in  mass,  thus  a  B.  A.  top  is 
about  half  the  weight  of  a  New  Zealand  top  of  the  same  size,  being  lighter 
fibered,  spongier,  and  more  springy.  They  are  excellent  for  worsted 
cross-bred  styles  as  they  give  more  body  to  the  fabric  than  Australians 
or  New  Zealands,  but  great  care  must  be  taken  in  finishing  processes  with 
these  wools. 

Argentina  is  also  noted  for  being  the  sole  producer  of  alpaca  from  a 
goat  of  that  name.  The  fiber  is  exceptionally  silky  and  of  good  length 
with  a  high  luster.     The  average  length  of  the  fiber  is  about  8  ins.  if  shorn 


^  Sheep  raising  for  wool  fiber,  however,  in  the  United  States  does  not  seem  to  be 
on  the  increase,  but  on  the  contrary  the  wool  production  during  recent  years  has  been 
decreasing.  The  consumption  of  wool  in  the  United  States  during  1922  was  about 
803,000,000  lbs.,  or  somewhat  over  7  lbs.  per  capita.  During  the  same  year  the 
United  States  produced  only  about  250,000,000  lbs.  of  wool  and  consequently  had 
to  import  about  550,000,000  lbs.  In  1913  the  United  States  produced  about  300,000,000 
lbs.  of  wool,  so  that  notwithstanding  the  considerably  increased  consumption  of  wool 
in  this  country,  its  cultivation  and  production  has  steadily  declined. 


50  WOOL:    ITS  ORIGIN   AND   CLASSIFICATION 

yearly,  and  it  is  grown  in  various  colors,  yellowish  brown,  gray,  white  and 
black  being  the  most  common.  It  is  made  into  luster  dress-goods  and  was 
introduced  as  a  material  for  textile  fabrics  by  Sir  Titus  Salt. 

11.  African  Wools. — Cape  Colony  and  Natal,  as  well  as  the  British 
Transvaal  and  Orange  River  Colony  are  making  much  headway  as  pro- 
ducers of  fine  merino  wools.  The  wool  is  very  soft  to  the  handle  and 
scours  a  good  white,  but  the  hardness  of  the  epidermal  scales  of  the  fiber 
renders  it  a  very  indifferent  milling  wool.  Nevertheless  it  is  a  very  useful 
qualit}',  having  been  much  improved  during  recent  years,  and  it  is  exten- 
sively used  for  hosiery  and  knitting  yarns  for  which  it  is  exceptionally 
well  adapted. 

Barker  states  that  Cape  Colony  and  Natal  are  essentially  fine  wool 
producing  countries,  but  double  clipping  is  often  in  evidence,  causing  the 
wool  to  be  suitable  only  for  filling  and  hosiery  yarns.  Cape  wool  is  very 
fine  and  silky,  but  usually  short  and  of  "clothing"  quality,  yielding  from 
60's  to  70's  quality.  The  yield  of  pure  fiber  is  often  as  low  as  30  percent, 
but  the  wool  scours  readily  and  is  very  white  in  color.  On  this  account 
Cape  noil  is  worth  more  than  Australian  noil.  The  fiber  of  Cape  wool 
is  clean  in  appearance  and  handle,  and  is  not  generally  strong,  but  it 
suits  the  clean-faced,  slippery  handling  cloth  into  which  it  is  made.  In 
Germany  it  is  used  in  considerable  quantities  for  lace-making.  As  a 
milling  wool  it  is  very  unsatisfactory. 

The  wool  from  the  east  of  Cape  Colony  is  a  very  inferior  class,  being 
profusely  infested  with  kemp  fibers.  This  quality  is  only  serviceable 
for  the  production  of  heavy  woolen  goods,  such  as  blankets  and  carpets. 

The  wool  of  Northwest  Africa  is  very  coarse  and  faulty,  due  very 
largely  to  neglect  in  its  cultivation.  In  Upper  Egypt  the  sheep  are  fairly 
well  looked  after,  and  produce  a  moderately  good  wool  of  a  medium 
quality.  The  native  sheep  of  Morocco,  Algiers  and  Tunis  are  poorly 
bred  creatures  that  produce  a  wool  of  a  coarse  and  indifferent  quality. 
These  results  are  undoubtedly  due  to  negligence  on  the  part  of  the  natives, 
as  some  of  the  native  sheep  of  Tunis  have  been  imported  into  Spain  and 
America  and  crossed  with  merino  sheep  with  good  results. 

12.  Asiatic  Wools. — The  Asiatic  breed  of  sheep  owe  their  origin  to  the 
wild  argali  or  moufflon  sheep  of  the  Asiatic  mountains.  In  Asia  the  flat- 
tailed  and  fat-rumped  sheep  abound,  giving  a  coarse,  rough,  matted  wool, 
which  is  only  suitable  for  carpets  and  low-grade  fabrics.  The  general 
characteristics  of  the  domesticated  varieties  are  similar  in  many 
respects  to  those  of  Palestine  and  Syria  and  are  coarse  and  faulty  and 
of  indifferent  length.  They  are  used  principally  for  low-grade,  heavy 
woolens. 

The  Persian  sheep  of  Central  Asia  produce  a  fine,  soft  wool  which  is 
used  by  the  natives  for  making  fine  shawls  and  carpets. 


ASIATIC  WOOLS  51 

The  different  classes  of  wool  produced  in  Persian  Azerbaijan  are: 

(1)  Khoi  wool,  which  is  produced  in  the  northwestern  part  of  Azerbaijan,  in  the 
districts  around  Khoi  and  Maku;  (2)  Urumiah  wool,  which  is  produced  southwest  of 
Lake  Urumiah,  in  the  Suduz  district  of  Urumiah  and  Ushnu;  (3)  Soujbulak  wool, 
produced  south  of  Lake  Urumiah;  (4)  Sakiz  wool,  produced  south  of  Lake  Urumiah; 
(5)  Salmas  wool,  produced  west  of  Lake  Urumiah;  (6)  Karadagh  and  Ardabil  wools, 
produced  in  the  northeastern  part  of  Azerbaijan,  in  the  district  between  Tabriz  and 
the  Caspian  Sea. 

Khoi,  Urumiah,  Soujbulak,  and  Sakiz  wools  are  all  suitable  for  use 
in  the  manufacture  of  carpets.  Khoi  wool  is  the  finest  carpet  wool 
produced  in  the  Province,  and  Sakiz  wool  the  poorest.  Khoi  is  long  and 
of  a  soft,  silky  texture.  The  best  Khoi  wool  is  produced  in  the  vicinity 
of  Maku.  Urumiah  wool  is  inferior  to  Khoi  wool,  and  Soujbulak  wool  is 
coarser  than  Urumiah  wool.  After  being  washed  Soujbulak  and  Sakiz 
wools  are  of  practically  the  same  quality,  but  the  unwashed  Sakiz  wool, 
which  is  commonly  sold  in  the  market,  is  dirtier  and  dustier  than  unwashed 
Soujbulak  wool. 

Salmas  wool  is  short,  coarse,  and  usually  red  in  color.  It  is  not  suit- 
able for  carpets,  and  is  used  by  the  native  population  for  making  clothing 
and  bedding.  It  is  rarely  exported  from  the  region  in  which  it  is  pro- 
duced. Karadagh  and  Ardebil  wools  are  also  unsuitable  for  carpets  and 
are  almost  entirely  used  by  the  native  population  for  making  clothing  and 
bedding. 

Wool  is  one  of  the  most  important  economic  products  of  Mesopotamia. 
Its  production  is  inexpensive,  and  in  normal  times  it  finds  a  ready  market. 
According  to  the  Director  of  Agriculture,  at  Bagdad,  wool  dealers  and 
exporters  of  Bagdad  recognize  three  distinct  varieties  of  Mesopotamian 
wools:  "Arabi,"  "Awassi"  and  "Karradi."  Arabi  is  the  name  given  to 
wool  from  the  sheep  owned  by  the  Arabs  of  the  plains  of  Iraq.  It  is  superior 
to  Awassi  and  Karradi,  and  compares  very  favorab^  with  the  best  wools 
of  India,  China  and  the  North  Coast  of  Africa,  including  Egypt.  This 
wool  is  exported  to  England,  where  it  is  used  in  the  manufacture  of  cloth. 
The  best  qualities  as  to  strength,  fineness,  softness  and  flexibility,  wavi- 
ness  or  curliness,  length  and  uniformity  of  staple,  luster,  etc.,  are  found 
among  the  browns  and  blacks.  The  whites  are  poorest  in  quality  and 
approximate  to  the  Awassi  wools.  Awassi  wool  comes  from  a  breed  of 
sheep  chiefly  owned  by  the  Arabs  whose  habitat  is  in  the  region  between 
Mosul  and  Aleppo.  This  breed  of  sheep  is  said  to  be  a  cross  between  the 
Arabi  and  Kurdish,  or  Karradi.  The  wool  produced  is  white  in  color,  is 
long  stapled,  coarser  and  less  wavy  than  Arabi,  but  superior  in  all  respects 
to  Karradi.  Karradi  is  a  commercial  name  of  the  wool  of  the  Kurdish 
sheep  bred  to  the  north  and  west  of  Mosul  on  the  Kurdish  hills.  In  color 
it  resembles  Awassi;  it  is  longish  in  staple,  very  slightly  curled;  the  fibers 


52 


WOOL:    ITS  ORIGIN  AND  CLASSIFICATION 

TABLE  OF  THE  VARIETIES 


Varieties  and  Sub-varieties. 


1.  Spanish     (Ovis    hispania;    of 
Linnteus) 


2.   Common  Sheep  {Oris  rnsticris 
of  Linnaeus) 

Sub- variety     (a),     Hornless 
Lincolnshire 


Sub- variety     (b),     Muggs     and 

Shetland 

Sub-variety  (c),  Ryeland 

Sub-variety  (d),  Southdown  . . . . 


Sub-variety  (e),  Old  Norfolk.  .  . 

Sub-variety  (/).  Old  Wiltshire.  . 

Sub-variety  (g),  Cornish 

Sub-variety  (A),  Bampton 

Sub-variety  (t),  Exmoor,  Notts. 
Sub- variety  (j),  Cotswold 

Sub-variety  (fc),  Improved  Tees- 
water  

Sub-variety  (1),  Silverdale 

Sub-variety  (m),  Penistone.  .  .  . 

Sub-variety  (n),  the  higher  Welsh 

Mountains 


Spanish 

Class   1,   Estantes  or  Sta- 
tionary 

(a)  Churrah 

(b)  Merino 

Class  2,  Migratory 

Swedish 

French 

Danish 

Saxon 

Prussian 

Silesian 

Hungarian 

Hanoverian 

New  South  Wales 

Victorian 

W.  Australian 

Queensland 

New  Zealand 

South  American 

South  African 

llnitcd  States 

British 

Lincolnshire 


Shetland 

Hereford 

Sussex 

Kent 

Hampshire 

Norfolk 

Wiltshire 

Cornwall 

Devonshire 

Exmoor 

Devonshire 

Durham,  York 

Lancashire 

West  Riding  of  Yorkshire 

The  Mountain  Sheep .... 


Cross. 


Staple  of 
Fleece. 


Merino  and  native.  .  .  . 
Merino  and  Roussillon. 
Leonese  and  native.  .  . 
Merino  and  best  native 
Merino  and  native.  .  .  . 


Merino  and 
Merino  and 
Merino  and 


Merino  and 


small  native . 
Southdown . . 
Leicester  . . . . 


Lincoln. 


Merino  and  Southdown. . 


Lincoln  and  Leicester. 


Southdown  and  Romney 
Marsh 

Southdown  and  old  black- 
faced  Berkshire 

Southdown  and  Norfolk  or 
Downs 

Southdown  and  Wiltshire 

Cornish  and  Leicester .  .  . 

Bampton  and  Leicester  . . 

Exmoor  and  Leicester.  .  . 

Cotswold  and  New  Leices- 
ter   


Teeswater   and    New 
cester 


Lei- 


Penistone  and  Leicester  . . 


Short 

Long  (Sins.) 
Short 

Long 

Medium 
Short 


Short 


Long 


Short 


Long 


Short 


VARIETIES  OF  SHEEP 


53 


!    OF  DOMESTIC  SHEEP 


Quality. 


General  Color. 


Combing  or  Carding. 


General  Application. 


Fine 

Black  and  white 

Rather  coarse 

White 

Very  fine 

* ' 

Soft,  fine 

White 

Soft  and  very  fine 

" 

Fine 

" 

Finest 

" 

Very  fine 

.. 

Fine 

.. 

Very  fine 

" 

Fine 


Good  and  glossy 


Very  fine 
Medium 

Fine 
Medium 


Fine 


Coarse 
Very  fine 
Medium 


Fine 

Good 

Moderate 

Fine 


Carding 

Combing 
Carding 


Combing  and  carding 

Carding 

Combing  or  carding 

Carding 
Combing  or  carding 


White 

White  and  gray 

White 


White 


Combing 


Combing  and  carding 


Combing 
Combing  and  carding 

Combing 


Carding 


Spanish  wools  obtained  from  the 
plains  are  of  the  merino  kind, 
and  are  chiefly  used  for  woolen 
goods;  but  that  obtained  from 
the  mountains  is  coarse  and  of 
unequal  quahty,  and  is  used  for 
various  low-class  goods 

Dress  goods  and  cashmeres 

Broad,  West  of  England,  billiard, 
and  fine  dress  cloths.  Silesian 
wool  is  almost,  if  not  quite,  the 
finest  in  the  world 


Dress  goods,  coatings,  etc. 
Meltons  and  pilots 
Hosiery 

Serges     for    suitings     and     dress 
goods 

Coatings,  etc. 

Dress  goods,  etc. 

Fine  dress  goods,  broadcloths,  etc. 


These  are  amongst  the  finest  of 
the  long-stapled  luster  wools; 
used  for  lustrous  worsteds, 
braids,  etc. 


The  finest  British  wools;    used  for 
I       dress   fabrics,    serges   and   flan- 
nels, etc. 


For  flannels  and  low  woolens 


Worsted  and  serges 


Blankets  and  flannels 


54 


WOOL:    ITS  ORIGIN  AND  CLASSIFICATION 

TABLE  OF  THE  VARIETIES 


Varieties  and  Sub-varieties. 


Sub-variety  (o),  Black-faced. 


Sub-variety  (p),  Hebridean.  .  .  . 

Sub-variety  («),  Shetland 

Sub-variety  (r),  Wicklow  Moun- 
tains   

3.  Seling  (Otis  selingia  of  Hodg- 

son)   

4.  Curumbar 

Garar 

5.  Morvant  de  la  Chine 

6.  Morocco  (Oeis  aries  numidiit 

of  H.  Smith) 

7.  Yenu,  or  Goitered  Sheep...  . 
Sub-variety,  Persian 

Sub-variety,  Fat-tailed 

Sub-variety,  Russian 

Sub-variety,  Thibetan 

Sub-variety,  Cape 

Sub-variety,  Buenos  Ayres 


Breed. 


Westmorland 

Cumberland 

Northumberland 

Scotland 

The  Hebrides 

Shetland 

The  Irish 

Nepaul,    central    hilly    re- 
gion, and  Eastern  Thibet 

Mysore 

India 

China 

Morocco 

Angola 

Persian 

Abyssinian 

Odessa 

Thibetan 

Cape  of  Good  Hope 

South  American  cross .  .  .  . 


Cross. 


Staple  of 
Fleece. 


Medium 

Long 

Medium 

Long 
Short 


Long 

Short 
Fur-like 


tend  to  coarseness,  and  the  fleece  staples  are  matted  with  locks  charac- 
teristic of  an  inferior  breed  of  sheep.  Awassi  and  Karradi  wools  are 
exported  from  Bagdad  to  America  and  there  used  in  the  manufacture  of 
carpets. 

The  Thibet  sheep  of  Northern  India  produce  a  wool  of  mixed  quality; 
the  finest,  after  sorting,  is  used  for  making  fine  shawls,  as  is  the  fiber  from 
the  cashmere  goat.  The  wools  of  East  India,  and  especially  those  of 
Madras,  are  of  very  low  and  coarse  quality.  They  are  invariably  of  a 
dusty  natui'e,  and  in  consequence  give  a  bad  yield.  The  wools  produced 
are  extensively  used  for  blankets  and  carpets. 

China  has  made  rapid  progress  during  the  past  decade  as  a  wool- 
producing  country.  The  wool  varies  from  coarse  to  exceptionally  fine 
and  silky,  though  it  seems  to  possess  a  tenderness  which  is  not  to  its  advan- 
tage. Large  quantities  of  Chinese  wools  are  shipped  to  America  for  the 
heavy  woolen  trade,  though  the  natives  make  a  fine  class  of  serge  from  some 
of  the  wools  they  produce. 


CLASSIFICATION  OF  FIBERS  IN   FLEECE 
OF  DOMESTIC  SREEF— Continued 


55 


Quality. 

General  Color. 

Combing  or  Carding. 

General  Application. 

Coarse 

White  and  gray 

Combing  and  carding 

Blankets,  carpet  yarns,  etc. 

Inferior 

White 

Combing  and  carding 

Tweeds,  etc. 

The  finest 

*  ' 

Carding 

— 

Medium 

— 

Carding  and  combing 

Woolen  friezes,  etc. 

Fine 

Some  breeds  black 

Carding 

East    Indian    wools    are   used   foi 
rugs,  carpets,  and  blankets 

Coarse 

White,  yellow,      1 

gray,  brown,     > 

Carding 

Blankets,  low  tweeds,  etc. 

" 

[      black                  J 

Rather  coarse,  but 

peculiarly    soft 

and  silky  to  the 

touch 

Yellow 

** 

Rugs  and  carpets 

Inferior  fine  and  soft 

White  and  gray 

" 

Felts,  rugs  and  blankets 

Fine  and  close 

— 

— 

— 

Medium 

White,  black,  fawn. 

yellow,  brown,  gray 

Combing 

— 

Fine 

— 

— 

Worsteds 







Used  for  fur  trimmings 

Fine  but  burry 

— 

— 

Fine  woolens,  etc. 

13.  Classification  of  Fibers  in  Fleece. — Sheep  in  their  natural  condition 
produce  two  kinds  of  hair:  the  one  giving  a  long,  stiff  fiber,  which  we  will 
call  "beard-hair";  and  the  other  a  shorter,  softer,  and  more  curly  fiber, 
which  we  will  designate  as  "wool-hair,"  or  true  wool.  By  domestication 
and  proper  cultivation  the  sheep  can  be  made  to  produce  the  latter  kind 
of  hair  almost  exclusively,  with  but  little  or  none  of  the  hairy  fiber.  Herein 
the  sheep  differs  essentially  from  the  goat,  as  the  latter  will  always  pro- 
duce both  kinds  of  fiber,  though  the  fineness  and  quality  of  its  hair  may 
be  much  improved  by  proper  cultivation.  According  to  Barker^  wild 
sheep  have  two  classes  of  fiber,  one  of  coarse  hair  showing  cell  structure 
and  the  other  of  fine  wool  showing  scale  structure.  It  is  also  found  that 
in  normal  sheep  living  under  domestic  conditions,  where  nature  does  not 
weed  out  one  fiber  and  leave  the  other,  there  is  a  tendency  to  grow  both 
coarse  and  fine  fibers  with  a  cell  structure  which  is  between  hair  and  wool 
and  is  neither  the  one  nor  the  other.  Along  with  this  nondescript  fiber 
1  Jour.  Text.  Inst.,  1922,  p.  43. 


56 


WOOL:    ITS  ORIGIN  AND  CLASSIFICATION 


will  be  found  strong  fibers  with  the  hair  ''mosaic"  structure  and  fine 
fibers  with  the  wool  "scale"  structure.  The  different  types  of  fibers 
are  show'n  in  Fig.  30,  ranging  from  the  thick,  coarse  hair  fiber  of  the 
primitive  so-called  Marco  Polo  sheep  with  the  "mosaic"  structure  on  the 
surface  to  the  fine  wool  fiber  with  the  overlapping  "scale"  structure. 

In  well-cultivated  sheep  the  wool-hairs  are  usually  united  in  tufts  or 
locks  containing  a  hundred  or  more  fibers.  Often  several  locks  are  con- 
nected into  one  large  one  called  a  staple,  the  hairs  joining  the  locks  together 
being  known  as  binders.  The  number  of  hairs  growing  on  each  square 
inch  of  the  sheep's  skin  is  between  4500  and  5500.  In  addition  to  the 
aliove-mentioned  varieties  of  hair,  most  sheep  grow  more  or  less  short, 
stiff  hairs,  or  undergrowth ;  these  have  no  value  as  textile  fibers.     It  must 


1  2  3  4  5 

Fig.  30. — Variations  in  Wool  Structure:  (1)  Hair  from  Marco  Polo  sheep;  (2)  Hair 
from  black-faced  sheep;  (3)  Nondescript  fiber  from  same;  (.4)  Fiber  changing 
toward  wool;   (5)  True  wool  fiber.     (Barker.) 


be  mentioned,  how^ever,  that  the  exact  character  of  the  wool  on  the  indi- 
vidual sheep  varies  considerably  with  its  position  in  the  fleece;  on  the 
extremities  of  the  animal  the  wool  becomes  more  hairy  in  nature,  and 
near  the  feet  the  short  undergrowth  of  stiff  hair  is  alone  to  be  found. 

14.  Wool-sorting. — The  texture,  length,  and  softness  of  the  fiber  differ 
considerably  in  different  portions  of  the  fleece.  Hence  it  becomes  neces- 
sary, in  order  to  obtain  a  homogeneous  mixture  of  fibers  with  properties 
as  constant  as  possible,  to  sort  out  the  fibers  of  the  fleece  into  different 
portions,  which  are  put  together  into  different  grades  of  wool  stock.  This 
operation  is  termed  wool-sorting  and  grading,  and  is  an  important  step 
in  the  manufacture  of  wool.  The  wool-sorter  works  at  a  table  or  frame 
covered  with  a  wire  netting  through  which  dirt  and  dust  fall  as  he  handles 
the  wool.  Fleeces  which  have  been  hard-packed  in  bales,  especially  if 
unwashed,  go  into  dense,  hard  masses,  which  may  be  heated  until  the 


WOOL   SORTING 


57 


softening  of  the  yolk  and  the  swelhng  of  the  fibers  make  them  pliable  and 
easily  opened  up.  When  the  fleece  is  spread  out  the  stapler  first  divides 
it  into  two  equal  sides;  then  he  picks  away  all  straws,  large  burrs,  and 
tarry  fragments  which  are  visible;  and  then  with  marvelous  precision  he 
picks  out  his  separate  qualities,  throwing  each  lot  into  its  allotted  recep- 
tacle. Sorting  is  very  far  removed  from  being  a  mechanical  process  of 
selecting  and  separating  the  wool  from  certain  parts  of  the  fleece,  because 
in  each  individual  fleece  qualities  and  proportions  differ,  and  it  is  only 


Fig.  31— British  Wools:  (1)  Nottingham;  (2)  Lincoln;  (3)  Yorkshh-e;  (4)  Notts 
Forest  Hog;  (5)  Notts  Forest  Wether;  (6)  Gloucester;  (7)  Lincoln  half-bred 
Hog;  (8)  Lincoln  half-bred  Wether;  (9)  Irish  Hog;  (10)  Irish  Wether;  (11) 
Southdown  Wether;  (12)  Southdown  Teg;  (13)  Shropshire  Wether;  (14)  Shrop- 
shire Hog;  (15)  Super  Stafford  Wether;  (16)  Super  Stafford  Hog;  (17)  Welsh 
Wether;  (18)  Welsh  Hog;   (19)  Scotch  Blackface;   (20)  Scotch.     (Tetley.) 

by  long  experience  that  a  stapler  is  enabled,  almost  as  it  were  by  instinct, 
rightly  to  divide  up  his  lots  so  as  to  produce  even  qualities  of  raw  material. 
Different  varieties  of  wool  may  require  different  systems  and  degrees 
of  sorting,  but  in  general  the  fleece  is  roughly  divided  into  nine  sections, 
given  as  follows: 

(1)  The  shoulders  and  sides  of  the  fleece  give  the  finest  and  most  even  staples 
of  fiber.  This  wool  possesses  the  best  strength,  length,  softness,  and  uniformity  com- 
bined. 

(2)  The  lower  part  of  the  back  yields  a  fiber  of  fairly  good  staple,  and  somewhat 
stronger. 


58 


WOOL:    ITS  ORIGIN  AND  CLASSIFICATION 


(3)  The  loin  and  back  give  a  shorter  staple,  and  the  fiber  is  not  as  strong  and  liable 
to  be  sandy. 

(4)  The  upper  part  of  the  legs  give  a  staple  of  moderate  length.  The  fiber  on 
this  part  is  frequently  in  the  form  of  loose,  open  locks  and  acquires  a  large  amount 
of  burrs  by  brushing  against  "stickers"  and  the  spinose  fruit  of  plants;  the  presence 
of  these  burrs  considerably  lessens  the  commercial  value  of  the  wool.  South  American 
wool  is  especially  liable  to  be  heavily  charged  with  burrs. 

(5)  The  upper  part  of  the  neck  gives  a  rather  irregular  staple  which  is  also  very 
frequently  filled  with  burrs,  and  hable  to  be  kempy. 


Fig.  32. — British  Colonial  Wools:  (1)  New  Zealand  clean  dry  hogs;  (2)  New  Zealand 
half-breds;  (3)  New  Zealand  greasy  cross-bred  lambs;  (4)  Buenos  Ayres  44/46's 
Hogs;  (5)  Buenos  Ayres  59's;  (6)  Geelorg  fine  cross-bred  hogs;  (7)  Geelong 
greasy  half-bred;  (8)  Choice  New  South  Wales;  (9)  Cooimbil  New  South  Wales; 
(10)  Sydney  lambs'  edges;  (11)  Geelong  super  combing;  (12)  Geelong  lambs' 
extra  super;  (13)  Geelong  good  stylish  clean;  (14)  Swan  River;  (15)  Swan  River 
good  ordinary  combing;  (16)  Swan  River  dark  growth;  (17)  Adelaide  lambs; 
(18)  Adelaide  greasy;  (19)  Cape  Colony  Steynburg;  (20)  Cape  Colony  Graf 
Reinet;  (21)  Cape  Colony  Adelaide;  (22)  Orange  River  Colony  Winburg;  (23) 
Orange  River  Winburg;  (24)  O.  B.  C.  Dewetsdorp;  (25)  O.  R.  C.  Harrismith. 
(Tetley). 

(6)  The  center  of  the  back  gives  a  fine  delicate  staple  similar  to  that  from  the  loins. 

(7)  The  belly,  together  with  the  wool  from  the  fore  and  hind  legs,  yields  a  poor 
staple  and  a  weak  fiber. 

(8)  The  tail  gives  a  short,  coarse,  and  lustrous  fiber,  frequently  containing  a  con- 
siderable amount  of  kemps. 

(9)  The  head,  chest,  and  shins  give  a  short,  stiff  and  straight  fiber,  opaque  and 
dead  white  in  color. 


WOOL  SORTING  59 

"Rigging"  is  a  term  applied  to  the  manner  in  which  the  fleece  is 
divided  through  the  middle  of  the  back  from  the  neck  to  the  tail  portion. 
This  method  of  division  is  shown  diagrammatically  in  Figs.  31  and  32. 

According  to  E.  W.  Tetley  (Textile  Manufacturer),  who  describes 
the  English  practice  of  sorting  wool,  all  wools  narrow  down  into  certain 
definite  standard  qualities,  and  it  is  the  best  way  for  testing  purposes  so 
to  consider  them.  The  quality  of  a  wool  indicates  the  probable  worsted 
counts  of  yarn  to  which  it  will  spin.  Thus  a  40's  quality  would  spin  a 
40's  yarn — that  is,  a  yarn  having  40  hanks  of  560  yds.  each  in  1  lb.,  or 
22,400  yds  to  1  lb.  It  will  be  seen,  however,  that  these  quality  numbers 
are,  except  in  the  finest  wools,  well  above  the  actual  spinning  counts.     The 


Hjilll^g 

wm 

J//f^^sJ//^ 

■Ea 

■a 

||]6]^B^^BB 

^B^^ 

wM 

Ri 

^'^^ 

^fT^^y"^^ 

Ik. .'  J 

V  jJ||B^H| 

Ki  '^' 'fl 

^^H^« 

IBIfli 

■1^^ 

^fi^^^^^^B 

■■■1 

^^^^^^^^H 

^^^H^^^H^^^^IIIfP^II^^I^^^^^^^H'EAsFlNDtAFr^^H 

BHBflMMHIHHIiPHIiHM^ 

Fig.  33. — Asiatic  and  African  Wools:  (1)  Donskoij;  (2)  Egyptian;  (3)  Morocco; 
(4)  Coarse  East  Indian;  (5)  Georgian;  (6)  Chinese;  (7)  Bagdad.  These  types 
are  hairy  in  character.     (Tetley.) 

following  lists  show  from  what  kinds  of  wool  the  various  qualities  are 
obtained: 

BRITISH  WOOLS 

28's  to  32's:    Mountain  Types. — Scotch  blackface  wethers  and  hogs;    Irish,  Scotch, 

and  Herdwick  ewes  and  wethers. 
32's  to  36's:  Mountain. — Irish  mountain,  best  Scotch  cross  wethers  and  hogs.     Lusters. 

— Lincoln  wethers  and  hogs,  Nottingham  wethers,  Yorkshire  wethers.     Demi. — 

Deep  Radnors. 
36's  to  40's:   Lusters. — Nottingham  hogs,  Leicester  wethers  and  hogs,  Ripon  wethers, 

Devons,  Yorkshire  hogs.     Demi-lusters. — Selected  Irish  wethers,  super  Stafford- 
shire wethers.     Demi. — Welsh  fleeces,  seconds. 
40's  to  44's:  Lusters. — Ripon  hogs,  North  wethers.     Demi-lusters. — Irish  wethers  (pick 

and  super),  Irish  hogs  (selected),  Kent  wethers    (selected),  super    Staffordshire 

hogs.     Demi. — Welsh  fleeces  best,  Lonk  ewes  and  wethers,  Cheviot  wethers. 
44's  to  46's:    Demi. — North  hogs,  Irish  hogs    (pick  and  super),  Kent  tegs  (selected) 

half-bred  hogs,  Norfolk  half-bred  hogs,  fine  Radnors,  Cheviot  hogs  (super) . 
46's  to  50's:  Demi. — Pick  Shropshire  hogs  and  wethers,  selected  Welsh  Eastern  Counties 

Down  ewes  and  tegs,  Hampshire  and  Oxford  Down  ewes  and  tegs. 
50's  to  58's:   Demi. — Wiltshire  and  Dorset  Down  tegs  and  ewes.  Southdown  tegs  and 

ewes. 


60  WOOL:     ITS   ORIGIN   AND   CLASSIFICATION 

These  British  wools  may  be  thus  summarised : 

Mountain  Wools. — Length  8  ins.  to  I5  ins.,  strength  deficient,  no  luster,  color  according 

to  soil;    handle  harsh,  brittle,  non-feltmg,  more  or  less  kempy;    yield  55  to  70 

percent  according  to  soU;  fineness  28's  to  the  best  of  50's  quality. 
Luster  Wools.- — Length  up  to  16  ins.,  very  strong  and  firm,  high  luster,  color  according 

to  soil,  non-feltuig;    yield  60  to  75  percent  according  to  soil;    fineness  28's  up  to 

44's  quality. 
Demi-luster. — E.g.,  a  cross  between  Lincoln  (pure  luster)  and  Shropshire  (non-luster). 

Length  up  to  8  ins.  or  10  ins.,  strong  and  firm,  "softish"  handle,  felting  indifferent; 

yield  60  to  70  percent;  fineness  up  to  48's  quality. 
HalJ-hreds. — Same  characteristics  as  Demi. 
Demi  (in  the  sense  of  non-luster).- — Length  up  to  4  ins.  or  5  ins.,  comparatively  strong, 

soft  handle,  felling  fairly  good;  yield  60  to  68  percent;  fineness  up  to  54's  quality, 

except  Southdowus,  which  go  up  to  58's,  and  are  the  best. 


COLONIAL  AND  OTHER  CROSS-BRED  WOOLS 

32's  to  40's:   Coarse  Cross-breds . — 12  ins.  downwards,  fairly  strong  and  lustrous,  harsh, 

felting  indifferent;  yield  60  to  70  percent. 
40's  to  50's:  Medium  Cross-breds. — 10  ins.  downwards,  very  strong  and  lustrous,  fairly 

fine  and  soft,  fair  felting  properties;   yield  55  to  65  percent. 
50's  to  5S's:    Fine  Cro.'^s-breds. — 6  ins.  downwards,  very  strong,  fair  luster  and  good 

color,  soft  handle,  good  felting  properties;  yield  about  50  to  60  percent. 


COLONIAL  AND  OTHER  MERINO  WOOLS 

58's  to  64's:  Strong  Merinos. — 4  ins.  downwards,  very  strong,  good  white  color,  very 
soft  handle,  very  good  felting  properties;  average  yield  40  to  50  percent. 

64's  to  80's:  Fine  Merinos.—^  ins.  downwards,  very  strong  and  white,  extra  soft,  with 
best  felting  properties;  average  yield  45  to  50  percent. 

As  regards  the  chief  wools  of  other  than  British  origin,  this  list  may  be 
summarised  as: 

Australasian. — The  best  tvi^es,  Port  Philip  being  extra  high  class. 

South  American. — Only  reach  about  60's  quality,  being  deficient  in  strength  and 
uniformity. 

Cape  (South  African)  are  also  inferior,  and  reach  about  64's.  They  are  singularly 
indifferent  to  felting.  It  must  be  again  noted  that  these  inferior  classes  are 
rapidly  improving  by  increased  care  and  attention  to  breeding. 

In  England  there  are  two  methods  of  sorting  generally  employed. 
The  first  is  known  as  the  Bradford  method,  in  which  the  fleece  is  divided 
into  two  portions  which  are  termed  the  ''rigs"  of  the  fleece.  The  terms 
employed  in  sorting  fleeces  for  woolen  qualities  are  as  follows:  (1)  Pick- 
lock, selected  from  the  shoulders;  (2)  Prime,  from  the  sides;  (3)  Choice, 
from  the  middle  of  the  back;    (4)  Super,  from  the  middle  of  the  sides; 


WOOL  SORTING 


61 


(5)  Seconds,  from  the  lower  part  of  the  sides;  (6)  Downrights,  from  the 
neck;  (7)  Abb,  from  the  hind  legs;  (8)  Britch,  from  the  haunches;  (9) 
Brakes,  from  the  edges  of  the  fleece;  (10)  Shorts  and  Pieces,  from  the 
edges  of  the  fleece  in  merinos  and  fine  cross-breds  (see  Figs.  34  and  35) . 

The  following  are  definitions  of  common  wool  teims:  Lamb's  Wool. — 
Up  to  seven  months  old.  Hog. — First  clip  off  sheep,  about  one  year  old. 
Teg. — Same  as  hog,  in  shorter  wools.  Both  hogs  and  tegs  are  naturally 
finer  and  longer  than  wethers,  and  are  thus  classed  about  four  qualities 
higher.  Wether. — After  first  clip.  Ram  and  Ewe  are,  of  course,  male  and 
female  respectively,  the  former  producing  longer  and  stronger  wool. 
Comeback  refers  to  the  wool  from  a  sheep  which  after  crossing  and  recross- 


A  B 

Fig.  34. — (.4)  Diagram  of  Woolen  Sorts;   (B)  Diagram  of  Merino  64's  to  70's  Quality. 


ing  comes  back  nearly  to  the  original  breed  or  type.    Super  is  finer  than 
Selected,  and  Pick  finer  than  Super. 

The  second  method  of  sorting  is  the  Scotch  method,  in  which  the  fleece 
is  sorted  whole,  and  the  different  portions  into  which  it  is  divided  are 
termed  ^^ matching s,''  these  are  known  by  different  terms:  (1)  super  is  the 
finest  portion  of  a  demi-luster  fleece;  (2)  fine  is  the  best  part  of  the 
shoulders  of  a  fine  luster  fleece  spinning  from  40's  to  44's  counts;  (3)  blue 
is  from  the  shoulders  cf  an  ordinary  luster  fleece  (Lincoln  and  Leicester) ; 
(4)  neat  is  from  the  sides  of  an  ordinary  luster  fleece  spinning  from  32' s  to 
34's;  (5)  brown  is  mostly  from  the  flanks;  (6)  britch,  from  the  tail  and 
thighs;  and  finally  (7)  cow-tail,  the  lowest  matching  from  the  long- 
wooled  fleeces. 


62 


WOOL:     ITS   ORIGIN   AND   CLASSIFICATION 


In  fine  English  wools  there  are  two  further  matchings:  extra  diamond 
from  the  shoulders  of  an  English  "down"  fleece,  and  spinning  54's  to  56's; 
and  diamond,  which  is  from  the  sides  of  the  same  fleece.  Brakes  is  a  term 
used  to  designate  the  skirting  or  edge  of  the  fleece;  it  is  always  used  for 
woolen  yarns. 


Fig.  35. — (A)  Diagram  of  Lincoln  Hog  18's  to  44's;    (B)  Diagram  of  New  Zealand 

Cross-bred  50's  Bulk. 


The  following  table  ^  shows  the  approximate  amounts  of  the  different 
qualities  contained  in  a  pack  (240  lbs.)  of  fleeces: 


Quality. 

Lincoln  Hogs, 
Pounds. 

Leicester  Hogs, 
Pounds. 

Irish  Hogs, 
Pounds. 

Fine  matchings 

Blue  matchings 

17.57 
149.03 
45.37 
5.80 
7.31 
2.67 
7.99 
1.31 
0.31 
0.03 
1.45 
1.16 

33.90 
139.96 
44.18 
5.19 
5.03 
2.68 
6.00 
0.36 
1.76 
0.02 
0.65 
0.30 

34.13 
144  30 

Neat  matchings 

First  brokes 

40.46 
4  87 

Second  brokes 

5.76 

Third  brokes 

3  54 

Britch 

4  49 

Tail 

0.60 

Cotts     

1.24 

Gray 

Toppings 

Waste 

0.50 
0.12 

1  Text.  Mfr.,  1908,  p.  185. 


CHARACTER  OF   FLEECE  63 

As  a  rule,  the  coarser  the  fleece  the  wider  the  variation  in  the  fibers; 
some  fleeces  contain  as  many  as  fourteen  quahties,  whereas  others  have 
only  two  or  three.  Merinos  are  often  used  in  an  unsorted  condition, 
after  being  classed  and  skirted  in  the  country  from  which  they  come,  the 
staples  being  of  a  remarkably  uniform  nature  throughout  the  entire 
fleece.  The  sorting  of  English  wools  usually  necessitates  a  general  classi- 
fication of  the  fleeces  into  two  lots  of  hogs  and  wethers  respectively.  The 
hog  wools  are  usually  of  finer  quality  and  may  be  recognised  by  the  taper 
points  of  the  fibers  indicating  a  first  clip;  wether  wool,  on  the  other  hand, 
is  square  ended  on  account  of  being  a  subsequent  clip. 

The  first  shearing  from  a  two-year  old  sheep  is  known  as  hog  (or  hogget) 
wool,  while  that  shorn  from  a  sheep  which  has  been  previously  clipped 
is  known  as  wether  wool.  The  finer  qualities  of  hog  wool  are  sometimes 
known  as  teg  wool.  In  hog  wool  the  natural  end,  or  point,  of  the  fiber  is 
preserved  whereas  in  wether  wool  both  ends  are  sheared. 

15.  Character  of  Fleece. — The  amount  of  fiber  in  the  fleece  varies 
greatly  with  the  breed,  sex,  age,  and  racial  conditions  of  the  animal.  The 
average  yield  from  the  ewe  is  1.75  to  4  lbs,  and  from  the  wether  3.5  to 
7.5  lbs. 

According  to  Barker,  the  following  table  gives  the  approximate  weights 
of  fleece  carried  by  different  varieties  of  sheep: 

Breed.  Weight  of  Meece. 

Merino  (Australian) 6       lbs. 

Merino  (South  American) 6.5 

Merino -Lincoln 8  to  10 

Southdown 6 

Lincoln 12 

Shetland 4 

Cashmere 4       ozs. 

In  1885  the  average  weight  of  wool  per  sheep  per  year  was  about  5  lbs., 
while  in  1911  from  7  to  8  lbs.  was  the  average  weight. 

The  bulk  of  wool  comes  into  commerce  in  the  form  of  fleece  wool,  the 
product  of  a  single  year's  growth,  cut  from  the  body  of  the  living  animal.^ 
The  first  and  finest  clip,  called  lamb's  wool,  may  be  taken  from  the  young 
sheep  at  about  the  age  of  eight  months.  When  the  animal  is  not  shorn 
until  it  attains  the  age  of  twelve  or  fourteen  months,  the  wool  is  known 
as  hog,  or  hogget,  and  like  lamb's  wool,  is  fine  and  tapers  to  a  point.     All 

1  Virgin  wool  is  a  term  which  has  arisen  in  the  consideration  of  various  "Truth-in- 
Fabric"  forms  of  legislation,  and  is  used  to  distinguish  wool  direct  from  the  fleece  from 
recovered  wool  obtained  from  manufactured  fabrics,  such  as  shoddy,  etc.  Hence 
virgin  wool  may  be  taken  to  include  fleece  wool,  pulled  wool,  slipe  wool,  or,  in  fact, 
any  wool  that  has  not  previously  been  manufactured  into  yarn  or  cloth. 


64  WOOL:    ITS  ORIGIN  AND  CLASSIFICATION 

subsequent  cut  fleeces  are  known  as  wether  wool,  and  possess  relatively 
somewhat  less  value  than  the  first  clip.  Fleece  wool,  as  it  comes  into  the 
market  is  "in  the  grease,"  that  is,  unwashed,  and  with  all  the  dirt  which 
gathers  to  the  surface  of  the  greasy  wool  present;  or  it  is  received  as 
washed  wool,  the  washing  being  done  as  a  preliminary  to  the  shearing; 
or,  in  a  few  cases,  it  is  scoured,  and  is  consequently  known  as  scoured 
wool}  Skin  wool  is  that  which  has  been  removed  by  a  sweating  process. 
The  worst  type  of  skin  wool,  known  as  slipe,  is  removed  from  the  skins  by 
lime,  which  naturall}^  affects  the  handle  of  the  wool  and  renders  it  difficult 
to  bring  into  a  workable  condition  later. 

Skin  and  slipe  wools  have  increased  considerably  of  late  years  owing  to 
the  development  of  the  frozen  mutton  trade.  The  sheep-skins  of  Australia, 
New  Zealand  and  South  America  are  mostly  dealt  with  from  special  centers 
of  trade,  the  chief  of  which  is  Mazamet,  France.  If  sodium  sulfide  has 
been  used  for  de-wooling  the  skins,  the  wool  is  generally  known  as  a 
Colonial  skin  wool. 

The  sweating  process  of  do-wooling  skins  consists  in  the  development 
of  bacterial  action  resulting  in  the  destruction  of  the  soft  connecting 
tissue  between  the  outer  skin  and  the  under  skin  and  also  of  the  roots  of 
the  fiber.  In  the  lime  method  the  soft  gelatinous  matter  in  the  skin  is 
dissolved,  and  as  the  agent  acts  on  the  wool  side  of  the  fleece,  useful 
portions  of  both  wool  and  skin  are  dissolved.  The  sulfide  method  depends 
on  the  power  of  sodium  sulfide  to  dissolve  the  wool  fiber  and  the  outer  skin 
without  affecting  the  skin  proper,  therefore  it  is  applied  from  the  inside 
of  the  skin,  and  the  action  must  be  carried  on  only  to  the  point  where 
the  fiber  roots  are  attacked  so  that  the  wool  may  be  readily  pulled  from 
the  skin.  A  new  method  for  de-wooling  skeep-skins  is  by  burning  the 
fiber  off  with  an  electrically  heated  wire;  it  is  claimed  that  the  skin  is 
left  intact  and  the  wool  fiber  is  equal  in  quality  to  sheared  wool.  The 
method,  however,  does  not  seem  to  have  come  into  general  commercial  use. 

Skin  wools  that  have  been  obtained  by  the  "  hme  "  method  of  pulling 
will  always  contain  a  considerable  amount  of  lime,  in  some  cases  as  much 

1  According  to  Barker,  about  three-fourths  of  the  wool  imported  into  England  is 
shipped  "in  the  grease";  a  very  small  and  diminishing  proportion  is  "fleece  washed," 
and  the  remainder  is  "scoured."  The  fleece  washing  may  be  eff'ected  either  on  the 
sheep's  back  or  in  the  fleece  form  after  shearing,  the  fleece  being  run  over  rollers  and 
subjected  to  a  spray  of  warm  water.  As  far  as  manufacturing  centers  are  concerned, 
wool  is  preferred  in  the  grease,  due  to  the  fact  that  scoured  wool  is  frequently  dis- 
colored and  felted.  Cape  wool,  however  dirty,  should  always  be  shipped  in  the  grease, 
as  the  fiber  is  so  fine,  soft  and  curly  that  after  press-packing  in  the  scoured  state  it 
cannot  be  opened  and  re-washed  without  considerable  injury.  It  is  stated  that 
merino  wools  can  be  better  judged  in  the  grease,  while  luster  wools  can  be  better 
judged  in  the  washed  state.  Most  of  the  wools  grown  in  England  are  washed  on  the 
sheep's  back. 


COMMERCIAL  GRADES  OF  WOOL  65 

as  8  percent,  and  as  each  pound  of  lime  will  render  useless  about  15  lbs. 
of  soap,  it  will  readily  be  seen  that  wool  of  this  character  will  not  be 
desirable.  Clean,  dry,  combed  tops  will  absorb  from  a  clear  saturated 
solution  of  lime-water  as  much  as  2  percent  of  its  weight  of  lime  (CaO). 

Wool  is  also  classified  as  clipped  (or  fleece)  and  pulled  wools;  the 
former  is  cut  from  the  living  sheep  and  forms  the  greater  part  of  the 
wool  appearing  in  trade ;  it  is  divided  into  long  and  short  staple,  or  combing 
and  clothing  wools.  Pulled  wool  is  pulled  by  the  roots  from  the  pelts  of 
dead  sheep.  Clothing  wools  are  used  for  broadcloth  and  heavy  cloth,  the 
combing  wools  for  the  thinner  fabrics  for  women's  wear.  Medium  wool 
is  used  for  worsted  goods,  alpacas,  mohairs,  etc.,  while  the  coarser  wools 
go  into  carpets,  blankets,  and  the  like. 

There  are  certain  terms  distinctive  to  American  wools.  Delaine  wool 
generally  means  the  Ohio  merino  and  the  finer  crosses,  and  the  delaine  wool 
of  Ohio  is  considered  the  strongest  merino  wool  in  the  world.  Territory 
wool  is  usually  applied  to  wool  from  west  of  the  Mississippi  River,  while 
fleece  wool  is  a  term  applied  to  wools  grown  east  of  the  Mississippi  River. 

16.  Commercial  Grades  of  Wool. — The  table  on  pages  66  and  67  given 
by  Radcliffe  and  Clarke,  of  the  various  commercial  grades  of  wool,  though 
somewhat  similar  to  the  preceding  tables,  differs  in  certain  particulars. 

17.  Carpet  Wool. — Carpet  wool  is  a  coarse  variety  of  wool.  Some  is 
obtained  from  Argentina,  in  which  country  it  is  known  as  criollo  (creole  or 
native)  wool.  In  America  it  is  called  cordova  (or  cordoba)  wool.  Owing 
to  admixture  of  the  native  breed  with  the  merino,  however,  a  finer  fiber 
is  now  generally  produced,  and  on  this  account  the  production  of  carpet 
wool  in  Argentina  has  been  decreasing.  The  creole  wool  is  largely  used  in 
Argentina,  for  the  making  of  mattresses,  as  it  retains  its  elasticity  more 
than  other  wools.  Carpet  wools  are  also  obtained  from  Russia,  Asia 
Minor,  Persia  and  China.  They  are  long,  coarse  and  hairy  in  character, 
usually  without  much  luster  and  with  little  waviness. 

18.  Statistics  of  Wool  Production. — According  to  estimates  made  by 
the  Market  Reporter  (1920)  the  total  annual  world  production  of  wool 
is  2,800,000,000  to  3,000,000,000  lbs.  One  estimate  divides  the  merino, 
cross-bred,  and  low  wools  as  follows : 

Lbs. 

Merino 869,000,000 

Cross-bred 1,135,000,000 

Low  wool 890,000,000 

Total 2,894,000,000 


66 


WOOL:    ITS  ORIGIN   AND   CLASSIFICATION 


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68  WOOL:    ITS  ORIGIN   AND   CLASSIFICATION 

Of  the  merino  wools,  more  than  half,  perhaps  60  percent,  is  produced 
in  countries  of  the  British  Empire  and  less  than  10  percent  in  South 
America.  North  America  is  estimated  to  produce  from  15  to  20  percent 
of  the  world's  crop  of  merino  wools.  Of  the  cross-breds,  South  America 
produces  more  than  30  percent  and  the  countries  of  the  British  Empire 
about  40  percent.  The  low  wools  come  largely  from  Russia,  China,  and 
other  eastern  countries. 

Some  idea  of  the  relative  production  of  the  various  countries  may  be 
obtained  from  the  following  summary  (1920)  of  the  world's  sheep: 

United  Kingdom 29,000,000 

Other  European  countries 151,000,000 

Total 180,000,000 

Australasia 103,000,000 

Asia 93,000,000 

North  America 55,000,000 

South  America 96,000,000 

Africa 65,000,000 

Total  world 592,000,000 

In  1895  there  was  an  estimated  total  of  522,000,000  sheep. 

SUMMARY  OF  THE  WORLD'S  WOOL  PRODUCTION  (1919) 

Lbs. 

Australasia 742,000,000 

South  America 470,000,000 

North  America 318,000,000 

Europe — 

United  Kingdom 125,000,000 

:                Russia  in  Europe 320,000,000 

I                France 65,000,000 

j                Germany 26,000,000 

Italy 22,000,000 

All  other 240,000,000 

Total 798,000,000 

Asia 273,000,000 

Africa 208,000,000 

World's  total 2,809,000,000 


STATISTICS  OF  WOOL 

PRODUCTION 

69 

UNITED  STATES  WOOL  PRODUCTION  i  (1919) 

i      Year. 

No.  of  Sheep. 

Production, 
Pounds. 

Imports, 
Pounds. 

Total  Production 

and  Imports, 

Pounds. 

1910 

52,448,000 

321,000,000 

180,000,000 

501,000,000 

1911 

53,633,000 

319,000,000 

156,000,000 

475,000,000 

1912 

52,362,000 

304,000,000 

238,000,000 

542,000,000 

1913 

51,482,000 

296,000,000 

152,000,000 

448,000,000 

1914 

49,719,000 

290,000,000 

260,000,000 

550,000,000 

1915 

49,956,000 

286,000,000 

413,000,000 

699,000,000 

1916 

48,625,000 

288,000,000 

449,000,000 

737,000,000 

1917 

47,616,000 

282,000,000 

421,000,000 

703,000,000 

1918 

48,603,000 

299,000,000 

454,000,000 

753,000,000 

1919 

48,866,000 

314,000,000 

446,000,000 

760,000,000 

1920 

48,615,000 

The  number  of  sheep  in  this  country  has  decreased  by  about  4,000,000 
during  the  last  ten  years.  Imports  of  wool  for  the  five-year  period  from 
1910  to  1914  were  less  than  half  of  the  five-year  period  following.  The 
total  of  production  and  imports  has  been  fairly  steady  since  1915.  The 
above  table  shows  that  the  production  of  wool  has  not  increased  in  this 
country  during  the  last  decade.^ 

1  There  seems  to  be  considerable  variation  in  the  statistics  of  sheep  and  wool  pro- 
duction in  the  United  States  according  to  the  figures  compiled  by  different  depart- 
ments or  trade  organisations.  The  statistics  for  1914  are  given  as  follows  by  one 
of  the  trade  associations : 

Number  of  sheep 31,904,416 

Average  weight  per  fleece 6.8  lbs. 

Wool 216,950,028      lbs. 

Pulled  wool 47,400,000      lbs. 


Total  clip 264.350.028      lbs. 


Prices  in  Boston  Market. 


January  1,  1914, 
Cents  per  Pound. 


January  1,  1915, 
Cents  per  Pound. 


Unwashed  Ohio  delaines 

Quarter-blood,  Ohio 

B  Supers  (scoured  basis) 

Fine  medium,  clothing  territory  (scoured) . 

Fine  staple  territory  (scoured) 

Jorias  (in  the  grease) 


22  @23 
24(ai25 
41@42 
50®  52 
53@55 
29@31 


25@27 
28@30 
58@60 
55@58 
58@60 
33@35 


-According  to  estimates  of  the  U.  S.  Department  of  Agriculture  the  wool  pro- 
duction for  the  Western  States  in  1920  was  as  follows: 


Production,  Pounds. 

Arizona 15,000,000 

Cahfornia 12,000,000 

Colorado 9,000,000 

Idaho 21,000,000 

New  Mexico 15,000,000 


Production,  Pounds. 

Nevada 10,000,000 

Oregon 13,000,000 

Wyoming 34,000,000 

Utah 16,000,000 


70  WOOL:    ITS  ORIGIN   AND   CLASSIFICATION 

ARGENTINA— NUMBER  OF  SHEEP  AND  EXPORTS  OF  WOOL 


Year. 

Number  of  Sheep. 

Exports  of  Wool, 
Pounds. 

1895 
1908 
1910 
1914 
1915 
1917 
1918 

74,000,000 
67,000,000 

43,000,000 
44,000,000 
45,000,000 

387,200,000 
332,000,000 
258,500,000 
259,400,000 
298,773,000 
256,613,000 

Argentina  seems  to  show  a  decrease,  or  at  least  a  stationary  condition 
similar  to  that  existing  in  the  United  States. 

AUSTRALIA— NUMBER  OF  SHEEP,  PRODUCTION  OF  WOOL  AND  EXPORTS 

TO  UNITED  STATES 


Year. 

Number  of  Sheep. 

Production, 
Pounds. 

Exports  to  United 
States,  Pounds. 

1910 

91,700,000 
92,900,000 
85,100,000 
69,700,000 
79,900,000 
86,700,000 

28,000,000 

1912 
1914 
1916 
1918 
1919 

663,000,000 
711,000,000 
551,000,000 
573,000,000 
652,000,000 

14,000,000 
29,000,000 
115,000,000 
65,000,000 
46,000,000 

From  data  given  by  Commerce  Reports  the  United  States  for  the  year 
ending  July  30,  1920,  imported  raw  wool  to  the  value  of  $212,848,568, 
and  manufactured  wool  to  the  value  of  $43,537,552.  During  the  same 
year  this  country  exported  wool  manufactures  to  the  value  of  $56,223,360. 
For  the  year  1919  the  amount  of  wool  in  the  United  States  available 
for  consumption  (including  both  domestic  growth  and  imports)  was 
6.8  lbs.  per  capita. 

The  following  tables  prepared  by  the  U.  S.  Department  of  Agriculture 
(1922)  show  the  production  of  wool  (computed  on  a  grease  basis)  in  the 
various  countries  of  the  world  (the  figures  for  1922  are  furnished  by  the 
Department  of  Commerce): 


STATISTICS  OF  WOOL  PRODUCTION 
WORLD  PRODUCTION  OF  WOOL 


71 


Countries. 


NORTH  AMERICA. 

United  States 

British  North  America 

Mexico 

Total 

Central    America    and    West 
Indies 

SOUTH  AJIERICA. 

Argentina 

Brazil 

ChUe 

Peru 

Falkland  Islands 

Uruguay 

All  other 

Total 

EUROPE. 

Austria 

Belgium 

Bulgaria 

Czecho-slovakia 

Denmark 

Finland 

France 

Germany 

Greece 

Hungarj^ 

Iceland 

Italy 

Netherlands 

Norway 

Poland 

Portugal 

Rumania 

Russia  and  Esthonia  (1922) . . 
Spain 


Average 

Annual 

Pre-war 

Production. 


Pounds. 
314,110,000 
11,210,000 
7,000,000 


332,320,000 
1,000,000 


358,688,000 

35,000,000 

17,430,000 

9,940,000 

4,324,000 

156,908,000 

5,000,000 


587,350,000 


15,360,000 

1,060,000 

23,700,000 

3,508,000 

80,688,000 

25,600,000 

14,000,000 

26,240,000 

1,980,000 

35,000,000 

3,556,000 

8,160,000 


10,000,000 

13,228,000 

320,000,000 

52,000,000 


Production  in 


1920. 


Pounds. 
302,207,000 
24,422,531 
750,000 


327,379,531 


750,000 


308,560,000 

27,000,000 

33,069,000 

9,420,000 

3,200,000 

100,000,000 

5,000,000 


486,249,000 


825,000 

17,802,000 

5,952,420 

3,508,000 

3,250,000 

39,400,000 

37,278,242 

16,000,000 

25,516,000 

1,980,000 

50,000,000 

5,500,000 

7,247,000 

6,724,000 

6,232,000 

13,228,000 

150,000,000 

142,000,000 


1921. 


Pounds. 
224,564,000 
24,050,000 
500,000 


249,114,000 


750,000 


286,000,000 
27,000,000 
33,069,000 
12,000,000 

3,200,000 
95,000,000 

5,000,000 


461,269,000 


1,205,000 

17,636,000 

5,952,420 

3,508,000 

3,250,000 

39,400,000 

42,975,000 

16,000,000 

25,516,000 

1,980,000 

50,000,000 

5,500,000 

7,247,000 

6,724,000 

6,232,000 

14,000,000 

150,000,000 

165,347,000 


1922. 


Pounds. 
261,095,000 
19,125,000 
792,000 


281,012,000 


750,000 


231,483,000 
27,000,000 
31,500,000 
15,000,000 
3,200,000 
80,000,000 
5,000,000 


383,183,000 


1,250,000 

825,000 

17,637,000 

4,303,000 

1,323,000 

8,300,000 

38,220,000 

51,809,000 

13,420,000 

9,370,000 

1,980,000 

50,000,000 

4,400,000 

4,409,000 

6,725,000 

7,717,000 

18,032,000 

163,224,000 

165,347,000 


72 


WOOL:    ITS  ORIGIN   AND   CLASSIFICATION 
WORLD  PRODUCTION  OF  WOOI^Continued 


Countries. 


EUROPE — Continued. 

Sweden 

Switzerland 

Turkey 

United  Kingdom 

Jugoslavia 

Others 

Total  Europe.  .  . 

ASIA. 

British  India 

China 

Persia 

Russia  in  Asia 

Turkey  in  Asia 

AU  other 

Total 

AFRICA. 

Algeria 

British  South  Africa .  .  . 

Tunis 

All  other 

Total 

OCEANIA. 

Australia  and  Tasmania 
New  Zealand 

Australasia 

All  other 

Total 

Grand  total 


Average 

Annual 

Pre-war 

Production. 


Pounds. 
6,060,000 
1,049,000 

28,000,000 
150,000,000 

25,446,000 


844,635,000 


60,000,000 
50,000,000 
12,146,000 
60,000,000 
90,000,000 
1,000,000 


273,146,000 


35,221,000 

157,761,470 

3,735,000 

13,000,000 


209,717,470 


705,146,000 
198,474,000 


903,620,000 
100,000 


903,720,000 

3,151,888,470 


Production  in 


1920. 


Pounds. 
5,354,000 
1,049,000 

100,000,000 
48,859,000 


687,705,057 


60,000,000 
50,000,000 
12,146,000 
45,000,000 
60,000,000 
1,000,000 


228,146,000 


33,184,000 

127,176,800 

3,735,000 

13,000,000 


177,095,800 


536,541,757 
181,480,000 


718,021,757 
100,000 


718,121,757 
2,625,447,145 


1921. 


Pounds. 
5,354,000 
800,000 

101,100,000 
23,800,000 


693,527,250 


60,000,000 
50,000,000 
12,146,000 
45,000,000 
60,000,000 
1,000,000 


228,146,000 


33,184,000 

127,176,800 

3,735,000 

13,000,000 


177,095,800 


631,290,000 
167,153,000 


798,443,000 
100,000 


798,543,000 
2,608,445,050 


1922. 


Pounds. 
6,613,000 
800,000 

103,217,000 
24,251,000 
15,000,000 


712,345,000 


60,000,000 
61,320,000 
12,146,000 
45,000,000 
60,000,000 
1,000,000 


239,466,000 


35,155,000 

187,000,000 

6,765,000 

19,175,000 


248,095,000 


618,475,000 
175,000,000 


793,475,000 


2,684,153,000 


The  following  tables  from  the  U.  S.  Census  Reports  (1922)  show  the 
magnitude  of  the  wool  industry  in  the  United  States : 


STATISTICS  OF  WOOL  PRODUCTION 


73 


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74 


WOOL:    ITS  ORIGIN  AND  CLASSIFICATION 
FIBERS  USED  IN  THE  WOOL  INDUSTRY 


Material. 


Total 

Scoured  wool  (equiva- 
lent)   

Wool  waste  and  noils.. . 

Recovered  wool  fiber . . . 

Purchr.sed 

Made  for  consumption 

Animal  hair 

Mohair,  camel,  alpaca 
and  vicuna  noils 

Cotton 


Pounds. 


Woolen- 
goods 
Industry. 


203,133,831 


86,547,717 
38,.522,i;5S 
49,081,630 
31,416,14.5 
17,665,485 
12,613,937 

1,7.38,489 
14,629,920 


Worsted- 
goods 
Industry. 


201,403,010 


177,288,745 

3,300,640 

2,224,011 

1,747,551 

476,400 

15,667,1,57 

176,974 
2,745,483 


Percent 
of  Total. 


Woolen- 
goods 
Industry. 


100.0 


42.6 
19.0 
24.2 
15.5 

8.7 
6.2 

0.8 
7.2 


Worsted- 
goods 
Industry. 


100.0 


88.0 


0.1 
1.4 


Percent 
Distribution. 


Woolen- 

goods 
Industry-. 

50 

2 

32 

8 

92 

1 

95 

7 

94 

7 

97 

4 

44 

6 

90 

8 

84 

2 

Worsted- 
goods 
Industry. 


49.8 


67.2 
7.9 
4.3 
5.3 
2.6 

55.4 

9.2 
15.8 


LEADING  PRODUCTS  OF  WOOL  BY  BRANCHES  OF  INDUSTRY 


Woolen 

Worsted 

Carpet  and 

Felt  Goods 
Industry. 

Wool-felt 

Product. 

Total. 

Goods 

Goods 

Rug 

Hat 

Industry. 

Industry. 

Industry. 

Industry. 

$1,234,657,092 

$364,896,590 

$700,537,482 

$123,253,828 

$39,229,540 

$6,739,652 

Woven  goods  for  per- 

sonal wear 

710,466,849 

287,030,146 

422,131, .592 

1,143,826 

161,285 

Carpets  and  rugs 

110,151,089 

7,.591 

27,520 

110,116,978 

Other     woven     goods 

(blankets,      carriage 

robes,  etc.) 

31,338,008 

28,765,972 

1,352,085 

505,939 

714,012 

Felt  goods 

37,843,349 

1,321,234 

36,522,115 

Wool-felt  hats 

5,574,974 

5,574,974 

237,971,867 
25,040,863 

31,337,200 
940,381 

205,697,251 
23,8.59,344 

.394,109 
209,521 

43,307 
31,617 

Wastes  and  noils 

All  other  products .... 

57,494,082 

10,235,571 

33,841,352 

10,681,168 

1,733,578 

1,002,413 

Contract  work 

18,776,011 

4,758,495 

13,628,338 

203,287 

23,626 

162,265 

CHAPTER  IV 
PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  WOOL 

1.  Physiology  and  Structure  of  Wool. — Wool,  in  common  with 
all  kinds  of  hair,  is  a  growth  originating  in  the  skin  or  cuticle  of 
the  vertebrate  animals,  and  is  similar  in  its  origin  and  general  compo- 
sition to  the  various 
other  skin  tissues  to 
be  found  in  animals, 
such  as  horn,  nails, 
feathers,  etc.  Wool 
is  an  organised  struc- 
ture growing  from  a 
root  situated  in  the 
dermis  or  middle 
layer  of  the  skin,  its 
ultimate  physical 
elements  being  sev- 
eral series  of  animal 
cells  of  different  forms 
and  properties.  Here- 
in it  differs  essen- 
tially from  silk,  which 
is  not  composed  of 
cells,  but  is  a  con- 
tinuous and  homo- 
geneous tissue. 

The    root    of    the 

wool  fiber  is  termed  the  hair  follicle  (Fig.  36);  it  is  a  gland  which 
secretes  a  lymphlike  liquid,  from  which  the  hair  is  gradually  developed 
by  the  process  of  growth.^  The  hair  folhcle  also  secretes  an  oil,  which  is 
supplied  to  the  fiber  during  its  growth  and  serves  the  purpose  of  lubri- 
cating its  several  parts,  giving  it  pliability  and  elasticity. 

1  If  the  form  of  a  hair  is  considered,  it  will  be  noticed  at  the  base  to  have  an  egg- 
shaped  swelling  or  root,  and  just  above  this  a  rather  contracted  portion  or  neck.  The 
hair  attains  its  greatest  breadth  usually  in  its  uppermost  third.  The  majority  of 
hairs  show  considerable  differences  in  appearance  when  examined  along  their  length 
(Hohnel). 

75 


Fig.  36. — Section  of  Skin:  (A)  Cuticle;  (B)  Rate  mucosum; 
(C)  Papillary  layer;  (D)  Corium;  (E)  Sudoriparous  glands; 
(F)  Fat  cells;  (G,  H)  Hair  foUicles;  (/,  J)  Oil  glands. 
(Bowman.) 


76  PHYSICAL  STRUCTURE   AND   PROPERTIES   OF   WOOL 

In  conjunction  with  the  hair  folhcle  there  also  occur  in  the  skin  numer- 
ous sebaceous  glands  which  secrete  a  fatt}^  or  waxy  substance,  commonly 
known  as  wool-fat.  This  substance  gradually  exudes  from  the  glands 
and  coats  the  surface  of  the  wool  in  rather  a  considerable  amount  (Fig.  37). 
It  affords  a  protective  coating  to  the  fiber  which  serves  to  preserve  the 
latter  from  mechanical  injurj^  during  its  growth,  and  also  prevents  the 
several  fibers  from  becoming  matted  and  felted  together.  In  the  prepara- 
tion of  wool  for  manufacture,  this  fatty  covering  has  to  be  removed,  the 
operation  constituting  the  ordinary  process  of  wool  scouring,  the  object 


Fig.    37. — Wool  Fiber  in  the  Grease.     (X500.)     (.4)  Irregular  lumps  of  grease  and 
dirt;  also  note  that  outline  of  scales  is  very  indistinct.     (Micrograph  by  author.) 

being  to  leave  the  fiber  clean  and  free  from  adhering  substances  (Fig.  38). 
There  is  also  a  wool-oil  which  is  contained  in  the  cells  of  the  fiber  itself, 
and  is  a  true  constituent  of  its  substance.  This  oil  should  not  be  removed, 
as  its  removal  causes  the  fiber  to  lose  much  of  its  elasticity  and  resiliency. 
The  oil  amounts  to  probably  about  1  percent  of  the  total  weight  of  the 
fiber,  whereas  the  external  fatty  matters  amount  on  an  average  to  about 
30  percent. 

2.  Morphology  of  Wool  Fiber. — Morphologically  considered,  the  wool 
fiber  consists  of  several  distinct  portions:  (a)  A  cellular  marrow,  or  medulla, 
which  frequently  contains  more  or  less  pigment  matter  to  which  the  wool 
owes  its  color;    (b)  a  layer  of  cellular  fibrous  substance  or  cortical  tissue 


MORPHOLOGY  OF  WOOL  FIBER 


77 


which  gives  the  fiber  its 
chief  strength  and  elasti- 
city; (c)  an  outer  layer, 
or  epidermis,  of  horn 
tissue,  consisting  of  flat- 
tened cells,  or  scales, 
the  ends  of  which  gen- 
erally overlap  each  other, 
and  project  outward, 
causing  the  edge  of  the 
fiber  to  present  a  ser- 
rated appearance  (Fig. 
39).  This  seal}'  covering 
gives  the  fiber  its  quality 
of  rigidity  and  resistance 
to  crushing  strain ;  it  also 
helps  the  fibers  to  felt 
together  on  rubbing 
against  one  another  by 
the  interlocking  of    the 


Fig.  39. — Diagram  Showing  Structure 
Fiber:  (M)  Medulla  or  marrow;  (C) 
Cells;   (S)  Scales  or  Epidermis. 


Fig.  38. — TjTDical  Wool  Fibers  after  Removal  of  Grease. 
(  X350.)     (Micrograph  by  author.) 


projecting  edges  of  the  scales. 

According  to  L.  A.  Haus- 
man  (Scientific  American),  hairs 
have  their  origin  in  the  bases 
of  relatively  deep  pits  in  the 
epidermis,  or  outermost  layer 
of  the  skin,  known  as  hair 
follicles,  and,  being  added  to 
from  the  base,  push  upward 
in  a  rodlike  growth,  of  circular 
or  elliptical  cross-section.  The 
hair  shaft  consists  of  four  struc- 
tural units:  (1)  the  medulla, 
commonly  termed  the  pith 
from  its  analogous  structure 
in  plant  stems,  which  is  built 
up  of  many  superimposed  cells 
or  chambers,  and  contains  air 
spaces  and  sometimes  small 
masses  of  pigment  material; 
of  Wool  (2)  *^^  cortex,  or  shell,  sur 
Cortical  rounding  the  medulla,  and 
composed    of    many   elongate, 


78 


PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  WOOL 


fusiform  cells,   coalesced  together  into  a  horny  homogeneous  mass,   of 
hyaline  texture  and  appearance;    (3)  the  pigment  granules,  to  which  the 


12  3  4 

Fig.  40. — Various  Hair  Fibers:     (1)   Hare;     (2)   Gray  squirrel;    (3)   Domestic    cat; 

(4)  Badger.     (Hausman.) 


12  3  4 

Fig.  41. — Various  Hair  Fibers:   (1)  Cow;   (2)  Horse;   (3)  Virginia  Deer;   (4)  American 

Beaver.     (Hausman.) 


12  3  4 

Fig.  42. — Various   Hair   Fibers:     (1)    Bactrian   Camel;     (2)   Guanoco;     (3)    Alpaca; 

(4)  Vicuna.     (Hausman.) 


12  3  4 

Fig.  43. — Various  Hair  Fibers:    (1)    Man,   Caucasian    female;     (2)   Same,   showing 
surface  scales;   (3)  Bat;   (4)  Cross-sections  of  human  hair  showing  pigment  cells. 

color  of  the  hair  is  primarily  due,  scattered  about  within  the  corticular 
substance;  (4)  the  cuticle,  or  outermost  integument  of  the  hair  shaft, 
lying  upon  the  cortex  and  composed  of  imbricated  scales. 


MORPHOLOGY  OF  WOOL  FIBER 


79 


Medullas  fall  into 
four  groups:  (1)  the 
discontinuous,  as  in 
the  hair  of  the  domes 
tic  cat  (Fig.  40,  No. 
3);  (2)  the  continu- 
ous, as  in  the  hair  of 
the  cow  (Fig.  41,  No. 
1);  (3)  the  interrupt- 
ed, a  type  interme- 
diate between  the 
first  two,  as  in  the 
hair  of  the  horse 
Fig.  41,  No.  2);  and 
(4),  the  fragmental, 
as  in  the  hair  of  the 
vicuna  (Fig.  42,  No. 
4).  It  will  be  noted 
that  the  hair  of 
some  species  ap- 
parently lacks  the 
medulla     altogether, 


Fig.  44. — Beard-hair  of  Doe.  (X350.)  Showing  small  de- 
velopment of  cortical  layer  and  large  medulla.  (Micro- 
graph by  author.) 


Fig.  45.— Wool  Fibers  Deficient  in  Medullary  Cells.  (X500.)  (A)  a  fiber  without 
evidence  of  medullary  cells;  (B)  a  fiber  showing  isolated  medullary  cells  at  M. 
(Micrograph  by  author.) 


80 


PHYSICAL  STRUCTURE   AND   PROPERTIES   OF   WOOL 


Fig.  46— Typlciil  Wool  Fiber.     (X500.) 


hair  shaft  as  con- 
tinuous ])an(ls, 
huikhng  up  the 
cuticle  somewhat 
hke  a  pile  of  tall 
tumblers  set  one 
within  the  other, 
as  in  the  hair  of 
the  intermediate 
bat(Fig.  43,  No.3). 
Of  these  two 
primal  t^^pes  there 
are  a  multitude  of 
intricate  variations. 
The  surface  hairs 
of  a  large  number 
of  mammals  are  of 
two  kinds:  a  soft, 
dense,  short,  fine 
hair,  called  the 
under  or  fur  hair, 
and      a      longer, 


though  minute  dis- 
sociated traces  exist 
in  certain  portions  of 
the  hair  shaft. 

The  cuticle  and 
its  component  ele- 
ments, the  scales,  aue 
of  two  diverse  types: 
(1)  the  imbricated 
interrupted  type, 
those  which  lie  singly 
overlapping  upon  the 
hair  shaft,  like  the 
shingles  on  a  roof  or 
the  scales  on  a  fish, 
as  in  the  hair  of  the 
badger  (Fig.  40,  No. 
4);  and  (2)  the  im- 
bricated coronal  type, 
which     encircle     the 


Fig.  47. — Comparison  of  Wool,  Cotton,  and  Silk  Fibers. 
(XoOO.)  W,  wool  fiber,  showing  marking  of  scales;  C, 
cotton;  S,  silk,  showing  irregular  shreds  of  silk-glue  at  iS/j. 
(Micrograph  by  author.) 


MICROSCOPY   OF  WOOL 


81 


coarser,  stiffer,  sparser  growth  which  projects  beyond  and  overlies  the 
fur  hair. 

Any  one  of  its  physical  constituents  may  at  times  be  lacking  in  a  wool 
fiber.  When  the  epidermal  scales  are  absent,  they  have  simply  been 
rubbed  off  by  friction;  this  condition  is  frequently  to  be  found  at  the 
ends  of  long  beard-hairs.  The  cortical  layer  of  fibrous  tissue  is  frequently 
but  slightly  developed,  especially  in  cases  where  the  medulla  is  large; 
in  some  instances,  indeed  (as  in  the  hair  of  the  doe.  Fig.  44),  the 
cortical  layer  appears  to  be  totally  absent  in  the  broadest  parts  of  the  fiber. 
The  medulla  is  very 
frequently  absent, 
or,  at  least,  shows  no 
difference  in  struc- 
ture from  the  cells 
of  the  surrounding 
cortical  layer  (Fig. 
45) ;  this  occurs 
more  especially  in  the 
wool-hairs,  but  is  also 
to  be  found  in  beard- 
hairs.  The  Zigarra 
wool  of  southern 
Hungary  has  beard 
hairs  which  show  no 
evidence  of  medul- 
lary cells.  On  the 
other  hand,  the  me- 
dulla is  occasionally 
more  largely  devel- 
oped than  the  cor- 
tical layer,  and  be- 
comes the  principal 
part  of  the  fiber,  as 
in  the  beard-hairs  of 
the  doe. 

3.  Microscopy  of  Wool. — The  microscopic  appearance  of  wool  is  suf- 
ficiently characteristic  to  distinguish  it  from  all  other  fibers.  Under 
even  moderately  low  power  of  magnification  the  epidermal  scales  on  the 
surface  of  the  fiber  can  be  readily  discerned  (Fig.  46),  while  neither  silk 
nor  the  vegetable  fibers  present  this  appearance  (Fig.  47).  The  scales 
are  more  or  less  translucent  in  appearance,  and  permit  of  the  under  cortical 
layer  being  seen  through  them.  The  exact  nature,  structure  and  arrange- 
ment of  the  scales  differ  considerably  with  different  varieties  of  wool.     In 


Fig.  48. — Comparison  of  Different  Varieties  of  Wool.  ( X500.) 
M,  merino  wool  with  only  a  single  scale  in  circumference 
of  fiber;  T,  territory  wool  with  two  or  more  scales;  C, 
coarse  wool  with  numerous  scales.    (Micrograph  by  author.) 


82  PHYSICAL  STRUCTURE   AND   PROPERTIES  OF  WOOL 

fine  merino  wools,  for  instance,  the  individual  scales  are  in  the  form  of 
cylindrical  cusps,  one  somewhat  overlapping  the  other;  that  is  to  say, 
a  single  scale  completely  surrounds  the  entire  fiber  (Fig.  48,  M).  In  some 
varieties  of  wool,  on  the  other  hand,  two  or  more  scales  occur  in  the  cir- 
cumference of  the  fiber  (Fig.  48,  T).  In  some  cases  the  edges  of  the 
scales  are  smooth  and  straight,  and  this  appears  to  be  especially  charac- 
teristic of  fine  qualities  of  wool;  the  coarser  species,  on  the  other  hand, 
possess  scales  having  serrated  wavy  edges.  Usually  such  scales  are 
much  broader  than  they  are  long  and  are  very  thin.  The  length  of  the 
free  or  projecting  edge  of  the  scale  is  also  a  very  variable  factor;  in  some 
wools  the  scale  is  free  from  the  body  of  the  fiber  for  about  one-third  of 
the  length  of  the  former,  and  in  consequence  the  scale  protrudes  to  a 
considerable  extent ;  such  wool  would  be  eminently  suitable  for  the  prepara- 
tion of  material  which  requires  to  be  much  felted.  In  other  wools  the  free 
edge  of  the  scale  amounts  to  almost  nothing,  and  the  separate  members 
fit  down  on  one  another  closely,  and  are  arranged  Ike  a  series  of  plates. 
Wools  of  this  class  are  more  hairlik(^  in  texture,  being  stiffer  and  straighter, 
and  not  capable  of  being  readily  felted  (Fig.  49).  The  wool-hairs  (the 
long,  stiff  fibers  which  have  previously  been  mentioned  as  occurring  to  a 
greater  or  lesser  degree  in  nearl}^  all  wools,  and  also  known  as  beard-hairs) 
usually  possess  this  structure.  The  felting  quality  of  wool  is  much 
increased  by  treatment  with  acid  or  alkaline  solutions,  or  even  boiling 
water;  the  effect  being  to  open  up  the  scales  to  a  greater  extent,  so  that 
they  present  a  much  larger  free  margin  and  consequently  interlock  more 
readily  and  firmly.  Woolen  yarns,  and  woven  materials  made  from 
such  yarns,  felt  much  more  easily  than  worsted  yarns,  due  to  the  fact  that 
the  fibers  of  the  former  lie  in  every  direction  and  the  interlocking  of  the 
scales  takes  place  more  easily. 

In  some  varieties  of  wool  fiber  the  scales  have  no  free  edge  at  all,  but 
the  sides  fit  tightly  together  with  apparently  no  overlapping;  in  such 
fibers  the  surfaces  of  the  scales  are  also  more  or  less  concave  (Fig.  50). 
This  structure  only  occurs  with  thick,  coarse  varieties  of  wool.  Fre- 
quently at  the  ends  of  the  wool  fiber,  where  the  natural  point  is  still 
preserved  (as  in  the  case  of  lamb's  wool  from  fleeces  which  have  not  been 
previously  sheared),  the  scales  are  more  or  less  rubbed  off  and  the  under 
cortical  layer  becomes  exposed  (Fig.  51,  P);  this  appearance  is  quite 
characteristic  of  certain  wools.  In  diseased  fibers  the  epidermal  scales 
may  also  be  lacking  in  places,  causing  such  fibers  to  be  very  weak  at  these 
points  (Fig.  51,  D). 

In  most  varieties  of  wools  the  scales  of  the  epidermis  may  be  readily 
observed  even  under  rather  low  powers  of  magnification,  while  under  high 
powers  the  individual  scales  may  be  seen  overlapping  one  another  like 
shingles  on  a  roof,  and  showing  pointed  thickened  protuberances  at  the 


MICROSCOPY   OF   WOOL 


83 


edges.  When  the  fiber  becomes  more  hairhke  in  natm-e,  such  as  mohair, 
alpaca,  camel-hair,  etc.,  it  is  more  difficult  to  observe  the  individual 
scales,  as  these  fuse  together  to  a  greater  or  lesser  degree,  until  the  true 
hair  fiber  is  reached,  which  exhibits  scarcely  any  markings  of  scales  at  all 
under  ordinary  conditions.  By  treatment  with  ammoniacal  copper  oxide, 
however,  the  interscalar  matter  is  dissolved  away,  and  even  with  true  hair 
the  scaly  nature  of  the  surface  may  be  observed. 


-m 


Fig.  49.  Fig.  50. 

Fig.  49.— Wool  Fiber  with  Plate-like  Scales.  (X340.)  (Hohnel.)  A,  portion  of 
fiber  with  isolated  medullary  cells  at  i,  and  smooth  scales  e  fitting  together  like 
plates;  B,  portion  of  fiber  showing  medullary  cylinder  at  in. 

Fig.  50. — Wool  Fiber  with  Concave  Scales.  (X340.)  (Hohnel.)  m,  medullary 
cylinder  consisting  of  several  rows  of  cells;  e,  concave  scales  arranged  in  a  plate- 
like manner. 


In  the  microscopical  examination  of  hair  and  wool  it  is  best  to  treat 
the  fiber  with  water,  as  this  causes  it  to  swell  somewhat  and  renders  the 
histological  characteristics  more  distinct.  As  natural  hairs  are  generally 
greasy  from  adhering  fat,  it  is  usually  necessary  to  first  cleanse  them  by 
treating  with  hot  alcohol  or  with  ether,  and  after  this  the  fiber  is  treated 
with  warm  distilled  water.  According  to  Hohnel  a  medulla-free  human 
hair  when  treated  with  water  swells  in  diameter  about  10  percent,  a  white 


84 


PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  WOOL 


alpaca  hair  about  13  percent,  an  angora  hair  10  percent,  and  a  cow-hair 
about  16  percent.  In  general  the  hairs  without  medulla  appear  to  swell 
about  10  to  11  percent  and  those  possessing  a  medulla  about  15  to  16  per- 
cent. Owing  to  the  swelling  of  hairs  in  this  manner,  microscopic  measure- 
ments of  the  diameter  should  be  made  on  air-dry  fibers,  or  if  the.  water- 
soaked  fiber  is  used  proper  allowance  should  be  made. 

In  determining  the  diameter  of  wool  and  hair,  it  is  also  to  be  noticed 
that  few  hairs  are  perfectly  round.  In  order  to  form  an  opinion  of  the 
sectional  form,  it  is  necessary  to  make  a  cross-section  or  observe  the 


Fig.  51. — Wool  Fibers  showing  Absence  of  Epidermal  Scales.     (X500.)     D,  at  middle 
portion  of  fiber,  probably  due  to  disease;    P,  at  point  of  fiber  of  lamb's  wool. 

(Micrograph  by  author.) 


hair  cut  in  short  pieces  under  the  microscope  and  to  turn  it  on  its  axis  by 
moving  the  cover  glass.  An  apparatus  has  been  constructed  which  stretches 
out  a  long  hair  and  turns  it  on  its  axis.  In  this  way  every  diameter  of  a 
hair  in  the  dry  condition  may  be  determined.  A  very  simple  contrivance 
but  one  which  suffices  for  the  majority  of  cases,  is  the  following,  which 
was  originated  by  Hohnel.  An  ordinary  slide-glass  is  taken  and  glued  at 
each  end  to  a  small  cork  by  means  of  sealing  wax,  and  through  these 
two  corks  is  stuck  a  thick  iron  wire  which  is  bent  at  the  outer  ends  into 
the  form  of  a  sort  of  crank,  so  that  they  may  easily  be  turned  on  their 
axes.     To  the  inner  ends  of  the  wires,  by  means  of  sealing  wax,  is  fastened 


MICROSCOPY  OF  WOOL 


85 


/    ^ 


y 


\ 


Fig.  52. — American  Merino,  Treated  with  Potash  and  Mounted  in  Water, 


86 


PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  WOOL 


the  hair  to  be  examined,  so  that  it  may  readily  be  turned  on  its  axis  and 

yet  be  kept  in  a 
stretched  condition. 
To  make  an  ac- 
curate microscopic 
examination  of  stiff 
beard-hairs,  bristles 
and  spines  it  is 
necessary  to  prepare 
cross-sections.  These 
may  rather  easily  be 
obtained  by  stretch- 
ing the  fibers  between 
two  pieces  of  cork 
and  cutting  with  a 
razor  blade  or  micro- 
tome, or  the  fibers 
may  be  mounted  in 
melted  stearin  or 
paraffin  and  cut  after 
Fig.  53. — Abnormal  Wool  Fibers  showing  Variations  in        cooling. 

Growth.  When  it  is  desir- 

able to  isolate  the 
individual  structural  elements  of  a  hair  from  each  other,  this  may 
be    accomplished    by    treatment    with     sulfuric    acid,     ammonia,     or 


'      )     J 


Fig.  54. — Fibers  of  American  Cotswold  Wool. 


MICROSCOPY  OF  WOOL 


87 


Ibaustic  potash.  In  using  sulfuric  acid  the  scales  are  detached 
singly  or  in  groups,  but  they  swell  up  so  much  that  their  form 
cannot  be  observed  very  distinctly.  With  caustic  potash  the  fiber  swells 
up  to  a  great  extent,  and  then  it  may  easily  be  decomposed  into  its  ele- 
ments by  pressure,  these,  of  course,  being  more  or  less  changed  by  the 
swelling.  The  most  suitable  method,  according  to  Nathusius,  is  to  use 
concentrated  ammonia;  after  two  to  three  minutes'  action  the  epidermal 
cells  are  detached  without  being  essentially  altered,  and  they  do  not  curl 
up,  so  that  their  form  can  be  nicely  studied.     Hohnel  has  used  chromic 


Fig.  55. — Fibers  of  American  Lincoln  Wool. 


acid  with  good  results;  ammoniacal  copper-oxide  may  also  be  employed 
advantageously.  Nitric  acid,  which  plays  an  important  part  in  the 
maceration  of  plant  tissues,  cannot  be  employed  for  the  same  purpose  on 
animal  fibers;  though  it  should  be  mentioned  that  this  reagent  colors  all 
horn-substance  an  intense  yellow,  and  therefore  is  useful.  If  all  forms  of 
fiber  are  included,  according  to  Hohnel  the  following  may  be  given  as  the 
general  microscopical  characteristics  of  sheep's  wool:  length,  2  to  50  cms.; 
quite  straight  to  very  finely  curled  and  bent;  very  uniform  to  very  irregular 
in  curl;  rough  to  lustrous;  5  to  100  microns  thick;  with  or  without 
medulla  and  medullary  islands.  Marrow,  when  present,  consisting  of 
1  to  4  rows  of  cells;  marrow  cells  round  or  long  to  linelike,  seldom  flattened; 


88  PHYSICAL   STRUCTURE   AND   PROPERTIES   OF   WOOL 

always  filled  with  finel}'  granulated  matter  and  air;  marrow  cells  never  ij 
arranged  quite  regularly.  Marrow  cord  very  narrow  or  as  much  as  four- 
fifths  the  breadth  of  the  fiber;  scarcely  striated  to  regularly  or  irregularly 
finely  to  coarsely  striated.  Epidermis  consists  of  flat  to  concave  scales  ij 
which  may  be  symmetrical  or  long  shaped  or  flattened,  often  semi-  or 
wholly  cylindrical.  These  scales  are  either  arranged  platelike  side  by 
side  or  overlap  each  other  like  tiles.  The  projecting  edge  of  the  scales  is 
generally  appreciably  thickened  and  strongly  refractive,  usually  almost 
flat,  often,  however,  drawn  forward  like  a  saw-tooth,  or  (seldom)  corroded 


Fig.  56. — Fibers  of  American  Merino  Woo 


SO  as  to  appear  serrated.  The  natural  point  of  the  hair  is  almost  always 
absent;  natural  points,  as  a  rule,  only  occur  with  any  frequency  in  wool 
of  the  first  shearing,  known  as  lamb's  wool,  hence  termed  lamb's  points; 
they  nearly  always  are  covered  with  overlapping  scales  which  form  com- 
plete or  almost  complete  cylinders;  they  have  no  "marrow  and  are  coarsely 
striated  by  reason  of  the  fibrous  cells.  Also,  hair  follicles  or  roots  are 
generally  absent,  since  the  wool  is  not  pulled  out,  but  sheared  off.  So- 
called  "  pulled  wool,"  which  is  removed  by  treatment  with  milk-of-lime, 
from  hides  that  are  to  be  tanned  subsequently,  is  the  only  kind  which 
shows  hair-roots ;  and  these  are  easy  to  recognise  by  their  slight  coloration 
and  egg-shaped  form. 


MICROCHEMICAL   REACTIONS  89 

4.  Microchemical  Reactions. — The  chemical  reactions  of  the  wool  fiber 
under  the  microscope  are  not  as  characteristic  as  its  physical  structure. 
With  concentrated  hydrochloric  or  sulfuric  acid  the  fiber  gradually  dis- 
solves with  a  red  coloration;  with  nitric  acid  it  dissolves  with  much 
difficulty  and  with  a  yellow  color;  ammoniacal  copper  oxide  causes  the 
fiber  to  distend  considerably  with  gradual  disintegration,  bringing  the 
scale  markings  into  prominence;  solutions  of  copper  or  ferric  sulfate  stain 
the  fiber  black. 

By  sugar  and  sulfuric  acid,  animal  hair  fibers  are  colored  red.  Dye- 
stuffs  of  all  kinds  (Fuchsine,  Aniline  Violet,  etc.)  are  readily  absorbed;  like- 
wise iodine.  Boiling  concentrated  chromic-acid  solution  dissolves  animal 
fibers  immediately;  likewise  boiling  caustic  potash.  On  the  other  hand, 
they  are  not  dissolved  by  boiling  hydrochloric  acid.  Boiling  picric  acid 
colors  the  animal  fibers  yellow,  the  coloration  being  permanent  in  cold 
water.  Millon's  reagent  (freshly  prepared  mercurous  nitrate)  on  boiling 
colors  animal  fibers  a  brick-red.  In  a  mixture  of  equal  parts  by  volume 
of  sulfuric  acid  (1.84)  and  concentrated  nitric  acid,  silk  and  goat-hair  are 
dissolved  in  about  thirty  minutes,  while  sheep's  wool  does  not  dissolve, 
being  merely  colored  yellow.  Since  the  animal  hair  fibers  all  contain 
sulfur,  they  yield  all  the  reactions  corresponding  to  that  element.  With 
lead  acetate  solution  (mixed  with  an  excess  of  caustic  alkali)  a  brown  or 
black  coloration  is  produced,  due  to  the  formation  of  lead  sulfide.  If 
animal  hair  fibers  are  boiled  with  caustic  potash  free  from  sulfur  and  then 
diluted  with  water,  the  latter  solution  is  colored  a  fine  violet  on  the  addition 
of  sodium  nitroprusside. 

5.  The  Epidermal  Scales. — The  epidermal  layer  of  scales  imparts  to  the 
wool  fiber  its  characteristic  quality  of  luster.  Since  the  luster  of  any 
surface  is  due  to  the  unbroken  reflection  of  light  from  that  surface,  it  msiy 
be  readily  understood  that  the  smoother  the  surface  of  the  fiber,  the  more 
lustrous  it  will  appear.  When  the  epidermal  scales  are  irregular  and 
uneven,  and  have  projecting  points  and  roughened  edges,  the  surface  of  the 
fiber  will  naturally  not  be  very  smooth  and  uniform,  and  consequently 
will  reflect  light  in  only  a  broken  and  scattered  manner.  Such  fibers 
will  not  have  a  high  degree  of  luster.  On  the  other  hand,  when  the  scales 
are  regular  and  uniform  in  their  arrangement,  and  their  edges  are  more 
or  less  segmented  together  to  form  a  continuous  surface,  the  fiber  will  be 
smooth  and  lustrous  (Fig.  57).  As  a  rule,  the  coarser  and  straighter 
fibers  are  the  more  lustrous,  as  they  approximate  more  closely  to  the 
structure  of  hair,  which  has  a  smooth  surface.  The  luster  of  the  fiber, 
being  dependent  on  the  polished  surface  of  the  scales,  is  influenced  largely 
by  any  condition  which  may  affect  the  latter.  Treatment  with  chemical 
agents,  for  instance,  which  will  corrode  the  horny  tissue  of  the  scales, 
will  seriously  affect  the  luster,  as  is  evident  by  allowing  alkaline  solutions 


90 


PHYSICAL   STRITCTURE   AND   PROPERTIES   OF   WOOL 


to  act  on  lustrous  wool  fibers.     High  temperatures  (and  especially  dry- 
heat)  corrode  the  epidermal  scales  and  shrivel  them  up,  causing  the  fiber 

to  lose  its  luster.  In_ 
the  various  mechani- 
cal processes  through 
which  the  wool  must 
pass  in  the  course  of 
its  manufacture,  the 
scales  of  the  fiber 
suffer  more  or  less  in- 
jury, being  torn  apart, 
roughened,  and  loos- 
ened from  the  surface. 
In  order  to  minimise 
the  extent  of  this  injury  the  wool  is  generally  oiled,  so  that  the  surface 
of  the  fibers  may  be  properly  lubricated. 

Bowman  gives  the  approximate  comparative  number  of  scales  per  inch 
in  different  varieties  of  wool  as  follows : 


Fig.  57. — Wool  from  same  Fleece,  showing  Coarse  and  Fine 
Fibers  and  Structure  of  Epidermal  Scales. 


Wool. 

Scales,  per  Inch. 

Diameter  of  Fiber,  Inch. 

East  Indian. . 

1000 

0.00143 

Chinese 

1200 

0.00133 

Lincoln 

1400 

0.00091 

Leicester 

1450 

0.00077 

Southdown.  . 

1500 

0.00080 

Merino 

2000 

0.00055 

Saxony 

2200 

0.00050 

According  to  the  measurements  of  Hanausek,  the  size  of  the  epidermal 
scales  on  different  forms  of  hair  fibers  are  as  follows: 


Fiber. 


No.  of  Epidermal  Scales  per 
Millimeter  Length  of  Fiber. 


Sheep's  wool,  ordinary . 
' '  prime . . . . 
' '  merino . . . 
"  Electoral. 
' '      Saxony' .  . 


Angora  wool.  . 
White  alpaca.. 
Brown  alpaca. 
Vicuna  wool .  . 
Camel's  wool . 


105 

97 

114 

100 

121 

53 

90 

150 

100 

90 


FELTING  QUALITY  91 

Hanausek  claims  that  the  number  of  scales  on  a  given  length  of  hair 
appears  to  be  constant  within  narrow  limits  for  each  kind  of  hair,  and  that 
in  the  case  of  wool  of  certain  animals,  particularly  the  merino  sheep  and 
Angora  goat,  the  results  of  counting  tests  are  of  considerable  value  in 
identification.  The  scales  on  Angora  wool  seem  to  be  the  most  uniformly 
distributed. 

With  respect  to  the  variation  in  fibers  derived  from  different  kinds  of 
sheep,  Bowman  gives  the  following  classification: 

(1)  Those  sheep  the  fibers  of  whose  wool  most  nearly  approach  to  a  true  hair,  the 
epidermal  scales  being  most  horny  and  attached  most  firmly  to  the  cortical  structure. 
This  class  includes  all  the  lustrous  varieties  of  wool,  besides  alpaca  and  mohair. 

(2)  Those  where  the  epidermal  scales,  though  more  numerous  than  in  the  first 
class,  are  less  horny  in  structure  and  less  adherent  to  the  cortical  substance  of  the 
fiber.  This  class  includes  most  of  the  middle- wooled  sheep  and  half-breeds.  When 
two  varieties  of  sheep  are  crossed  in  breeding  the  wool  from  the  resulting  offspring  is 
known  as  "cross-bred."  Such  wool  has  a  tendency  to  produce  uneven  staple  unless 
proper  care  and  selection  are  exercised  in  the  crossing. 

(3)  Those  where  the  characteristics  of  true  wool  are  most  highly  developed,  such 
as  suppleness  of  fiber  and  fineness  of  texture,  the  epidermal  scales  being  attached  to 
the  cortical  substance  through  the  smallest  part  of  their  length.  This  class  includes 
all  the  finest  grades  of  sheep,  such  as  the  merino  and  crosses  with  it. 

The  rigidity  and  pliability  of  the  wool  fiber  are  also  largely  conditioned 
by  the  nature  of  its  epidermal  scales.  If 
these  fit  over  one  another  loosely  with  con- 
siderable length  of  free  edge,  the  fiber  will 
be  very  pliable  and  plastic,  soft,  and  yield- 
ing, also  easily  felted  (Fig.  58).  Whereas, 
if  the  scales  fit  closely  against  one  another 

and  have  little  or  no  freedom  of  movement,  .^  _ 

,1      £,  -n  ,  ,.£c         J         .  ,       ,  ]    i'lG.  58. — Diagram  showing  Felt- 

the  fibers  will  be    stm    and  resistant,  and      •       ...     %  ttt    i  u    t  * 

'  mg  Action  of  Wool  by  Inter- 

not  easily  twisted  together  nor  felted.  locking  of  Scales.    (Drawing  by 

6.  Felting  Quality. — The  felting  quality      author.) 
of  wool  is  dependent  to  some  extent  on  the 

nature  of  the  epidermal  scales,  as  pointed  out  above.  The  more  the  free 
edge  of  the  scale  protrudes  from  the  surface  of  the  fiber,  the  more  easily 
will  the  wool  felt. 

The  felting  action  of  wool,  however,  must  not  be  attributed  solely  to 
the  interlocking  of  the  scales  on  the  surface  of  the  fiber.  This  has  been 
the  general  conception  in  the  past,  but  the  examination  of  felted  fibers 
does  not  bear  out  this  idea.  If  the  felting  were  altogether  due  to  the 
interlocking  of  the  scales  it  would  require  that  two  fibers  be  brought 
together  in  opposite  directions  in  order  to  have  this  interlocking  take  place. 
As  a  matter  of  fact,  in  a  piece  of  felted  cloth  for  example,  the  wool  fibers 
are  located  in  all  manner  of  directions  and  only  a  small  percentage  of  them 


92 


PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  WOOL 


Fig,  59.— Fibers  in  Unfelted  Woolen  Cloth. 


would  be  juxtaposed  in  such  a  manner  as  to  furnish  the  necessary  con- 
ditions for  felting  by 
the  interlocking  of  the 
scales.  The  felting  is 
largely  due,  in  the 
first  place,  to  the 
intermeshing  of  the 
fibers  themselves  by 
becoming  twined 
round  one  another, 
and  this  condition  is 
especially  enhanced  by 
the  curl  in  the  fiber. 
Again,  in  the  felt- 
ing operation  of  mill- 
ing or  fulling  the  sur- 
face of  the  fiber  no 
doubt  is  softened  in 
such  a  manner  that 
fibers  coming  in  con- 
tact with  one  another 
and  under  the  in- 
fluence of  heat,  pressure  and  the  chemicals  employed,  become  more  or 
less  glued  together. 
As  the  substance  of 
the  scales  of  the  fiber 
is  in  reality  a  form 
of  glue  or  gelatine,  it 
is  easy  to  understand 
why  this  condition  can 
readily  be  induced  by 
the  felting  process. 
Microscopic  examina- 
tion of  the  intimate 
structure  of  felted 
fibers  indicate  a  strong 
surface  cohesionrather 
than  a  mere  interlock- 
ing of  the  scales  (Figs. 
59  and  60).  This  also 
explains  why  it  is  per- 
fectly possible  to  felt 
wool  fibers  that  do  not       Fig.  60. — Felted  Fibers  in  Woolen  Cloth  after  Fulling. 


THE  CORTICAL  CELLS  0^ 

exhibit  well-defined  free  scales.  Hair,  though  it  has  the  surface  scales,  does 
not  have  these  scales  arranged  so  as  to  show  very  much  free  edge  projecting 
from  the  surface  of  the  fiber;  also  these  scales  are  hard  and  not  easily  soft- 
ened to  the  point  where  strong  cohesion  may  take  place  between  fibers  in 
contact  with  one  another.  If,  however,  the  surface  scales  are  softened  so 
that  they  become  somewhat  mucilaginous  in  character,  then  by  heat  and 
pressure  hair  fibers  may  also  be  felted  much  in  the  same  manner  as  ordinary 
wool  fibers.  Burgess  is  of  the  opinion  that  the  sole  cause  of  felting  in 
wool  is  the  curled  nature  of  the  fiber,  and  that  the  serrations  on  the  surface 
have  nothing  whatever  to  do  with  it.  He  quotes  certain  Russian  wool 
which  has  very  strongly  developed  serrations  but  which  is  not  a  good 
felting  wool.  Bowman,  on  the  other  hand,  inclines  to  the  opinion  that  the 
serrations  or  scale  projections  on  the  surface  of  the  fiber  are  the  chief 
cause  of  the  felting.  While  both  of  these  factors  are  no  doubt  causes 
of  felting,  the  present  author  is  of  the  opinion  that  they  only  partially 
explain  the  facts  and  that  the  above-mentioned  fusing  together  of  the 
surface  of  the  fibers  is  the  principal  cause  of  felting.  Even  Bowman,  in 
speaking  of  the  action  of  water  in  felting,  states  that  the  constituent  cells 
of  the  fiber  become  softened  by  the  action  of  the  water  and  the  acid,  and 
seem  to  be  capable  of  uniting  with  each  other  when  subjected  to  rubbing 
and  pressure,  until  it  is  difficult,  even  under  the  microscope,  to  distinguish 
one  fiber  from  another,  the  whole  seeming  to  form  one  solid  mass.  It  is 
not  necessary  for  the  fibers  to  be  woven  into  a  cloth,  or  arranged  in  a 
regular  manner  so  as  to  felt;  indeed  the  reverse  is  the  case,  for  the  less 
regularity  there  is  in  the  arrangement  of  the  fibers,  the  better  and  more 
perfect  is  the  felting  action. 

7.  The  Cortical  CeUs. — The  cortical  layer,  or  true  fibrous  portion  of 
the  fiber,  forms  the  major  constituent  of  wool.  It  consists  principally  of 
more  or  less  elongated  cells,  and  often  presents  a  distinctly  striated 
appearance,  the  striations  being  visible  through  the  translucent  layer  of 
scales.  The  individual  cells  measure  from  0.0014  in.  to  0.0025  in.  in 
length,  and  from  0.00050  in.  to  0.00066  in.  in  diameter,  hence  are  elliptical 
in  form.  The  cells  may  be  separated  from  one  another  by  a  careful 
treatment  with  caustic  alkali  (Fig.  61).  To  this  cortical  tissue  the  fiber 
chiefly  owes  its  tensile  strength  and  elasticity. 

8.  Waviness  or  Curl. — When  the  fiber  is  fine  in  staple,  the  cortical  cells 
exhibit  more  or  less  unevenness  in  their  growth  and  arrangement,  with  the 
result  that  the  fiber  is  contracted  on  one  side  or  the  other,  giving  rise  to 
the  waviness  or  curled  appearance  of  such  wools.  It  is  best,  perhaps,  to 
speak  of  the  wool  being  "wavy"  rather  than  "curled,"  as  the  latter  im- 
plies usually  a  spiral  development  which  involves  a  twisting  of  the  fiber, 
and  in  wool,  as  a  rule,  this  does  not  occur.  Coarse  wools  seldom  exhibit 
this  wavy  structure,  or  only  to  a  slight  degree,  the  waves  being  long  and 


94 


PHYSICAL  STRUCTURE   AND  PROPERTIES  OF  WOOL 


irregular;  some  fine  stapled  wools,  on  the  other  hand,  possess  short  and 
very  regular  waves.  This  property  of  the  fiber  adds  much  to  its  spinning 
qualities,  and  also  to  the  resiliency  of  the  ^^arn  or  fabric  into  which  it  is 
manufactured. 


Fig.  61. — Fiber  of  Wool  Decomposed  into  its  Constituent  Cells  by  Alkali,  showing 
Thin,  Flat,  Plate-like  Scales  and  Long,  Narrow  Cortical   Cells.     (Lobner.) 

Lafoun  gives  the  following  table  showing  the  relation  between  the 
diameter  of  the  fiber  and  the  number  of  curls : 


No. 


Quality. 


Super  Electa . . . 

Electa 

Prima 

Secunda  Prima. 

Secunda 

Tertia 

Quarta 


Curls  or 
Curves  per  Inch. 


27  to  29 
24  to  28 
20  to  23 
19  to  20 
16  to  17 
14  to  15 
12  to  13 


Diameter  of  Fiber. 


7  3  5 

1    th 
6  6  0  '^^ 

1 

510 


j^th  of  an  inch 
th 


th 
rth 


It  will  be  seen  in  this  table  that  the  finer  the  wool  the  greater  the 
tendency  to  curl;  for  when  the  diameter  of  the  fiber  is  1/840  in.  the 
number  of  curves  is  more  than  double  that  which  pertains  to  the  fibers 
whose  diameter  is  1/470  in. 

Wool-hairs  exhibit  much  less  development  of  waves  than  the  true  wool 


WAVINESS  OR  CURL 


95 


fibers,  and  the  more  closely  the  animal  fibers  approximate  to  the  structure 
of  ordinary  hair,  the  less  pronounced  are  the  waves.  Sheep's  wool  is  more 
wavy  than  that  derived  from  allied  species,  such  as  the  various  goats, 
camel,  etc.  Mohair,  for  instance,  exhibits  no  wavy  structure  at  all. 
The  exact  cause  which  determines  the  wavy  quality  of  wool  is  but  ill 
defined;  there  appears,  however,  to  be  some  connection  between  the 
waviness,  the  diameter  of  the  fiber,  and  the  number  of  scales  per  inch. 
The  following  table,  given  by  Bowman,  shows  the  relation  between 
the  number  of  waves  and  the  diameter  of  the  fiber. 


Wool. 

Waves  per  Inch. 

Diameter  of  Fiber,  Inch. 

English  merino 

Southdown 

24  to  30 

13  to  18 

11  to  16 

7  to  11 

3  to    5 

2  to    4 

0.00064 
0.00078 
0.00100 

Irish 

Lincoln  

Northumberland 

0.00120 
0.00154 
0.00172 

The  fineness  of  the  wool  fiber  appears  to  bear  a  definite  relation  to  its 
waviness,  and  attempts,  therefore,  have  been  made  in  Europe  to  grade 
the  fiber  according  to  the  number  of  waves  in  one  centimeter,  as  follows: 
Super  electa,  over  11;  electa,  9-10;  prime,  7-9;  second  quality,  6-7; 
third  quality,  5-6;  fourth  quality,  4-5.  The  different  kinds  of  waves, 
known  as  normal  bent,  close  bent,  high  bent,  flat  bent,  and  long  bent, 
also  appear  to  be  due  to  differences  in  the  fineness,  although  but  little  is 
known  on  this  point  as  yet. 

Bohm  (Schafzucht,  vol.  I,  p.  182)  gives  the  following  table  for  the 
number  of  waves  or  crimps  in  various  kinds  of  wool : 


Number 

of 

Crimps 

per 

Inch. 

Measurements  of  Fineness. 

Grade. 

In  Centi- 
millimeters. 

In  Thousandths  of 
an  Inch. 

In  Fractions 
of  an  Inch. 

Super  Electa  plus  plus . . 

Super  Electa  plus 

Super  Electa 

32 
30  to  32 
28  to  30 
26  to  28 
24  to  26 
23  to  24 
21  to  23 
20  to  21 
19  to  20 
17  to  19 
16  to  17 
13  to  16 
0  to  13 

1.25    to  1.50 
1.50    to  1.60 
1.65    to  1.775 
1.775  to  1.90 
1.90    to  2.03 
2.03    to  2.225 
2.225  to  2.40 
2.40    to  2.54 
2.54    to  2.666 
2.666  to  2.90 
2.90    to  3.175 
3.175  to  3.70 
3.70 

0.4921  to  0.5905 
0.5905  to  0.6496 
0.6496  to  0.6988 
0.6988  to  0.7480 
0.7480  to  0.7885 
0.7885  to  0.8759 
0.8759  to  0.9448 
0.9448  to  0.9999 
0.9999  to  1.0496 
1.0496  to  1.1417 
1.1417  to  1.2499 
1.2499  to  1.4566 
1.4566 

1      tn      1 

2031  '^^  1693 

1      tn       1 

1693  "-"1587 

1        +r,         ^ 
1587^"  1430 

1       tn       1 

1430  '''^1336 

1      tn       1 
1336  ^"1267 

1        +n         1 
1267^"  1141 

1      to      1 

1141   ^-"1058 

1       to       1 

1058^"     999 

1      tn      1 

9  99    ^"    95  2 

1      tn      1 

95  2     ^'^    875 
875    ™    799 
7  99    t'O    686 
686 

Prima  Electa 

Secunda  Electa 

Hohe  Prima 

Prima 

Geringe  Prima 

Hohe  Secunda 

Secunda 

Geringe  Secimda 

Tertia 

Quarta 

96 


PHYSICAL  STRUCTURE  AND   PROPERTIES   OF   WOOL 


The  waviness  of  the  wool  fiber  may  be  temporarily  removed  by  wetting 
with  hot  water  and  drying  while  in  the  stretched  condition. 

9.  The  Medullary  Cells. — The  medulla,  or  marrow,  of  the  wool  fiber 
consists  of  round  or  slightly  flattened  cells,  usually  somewhat  larger  in 
section  than  those  comprising  the  cortical  layer.  The  size  of  the  medulla 
varies  considerably  in  different  varieties  and  grades  of  wool,  and  even 
shows  large  variations  in  fibers  from  the  same  fleece.  At  times  it  ma^ 
occupy  as  much  as  one-quarter  to  one-third  of  the  entire  diameter  of  the 
fiber;  and  again,  it  ma}^  be  reduced  to  almost  a  line,  or  even  disappear 
completely    (Fig.    62).     Wool-hairs   exhibit   the    presence   of   a   distinct 

medulla  more  frequent- 
ly than  the  true  wool 
fibers.  The  latter 
mostly  show  scarcely 
any  inner  structure  at 
all,  though  at  times 
there  may  be  noticed 
isolated  medullary 
markings,  but  usually 
the  fiber  is  so  trans- 
parent that  it  presents 
no  markings  at  all.  In 
camel-hair,however,the 
medullary  portion 
shows  up  very  distinct- 
ly, in  some  fibers  ap- 
pearing as  a  continuous 
dark  band  occurring 
about  three-fourths  of 
the  width  of  the  fiber, 
while  in  other  fibers  it  shows  a  well-defined  granular  structure.  In 
hairs  of  some  other  animals  the  medullary  part  exhibits  a  structure  which 
is  distinctly  characteristic  of  the  fiber;  in  the  hair  of  the  cat  (Fig.  40, 
No.  3),  for  instance,  the  medullary  cells  appear  in  a  reticulated  form, 
and  in  the  hair  of  the  rabbit  (Fig.  40,  No.  1)  they  occur  as  a  series  of 
laminae  very  regularly  superposed  on  each  other. 

The  medulla  may  consist  of  a  single  series  of  cells,  or  of  several  series 
arranged  side  by  side;  sometimes  these  cells  occur  in  a  discontinuous  and 
rather  irregular  manner,  the  intervening  spaces  of  the  medulla  being 
filled  with  air  which  is  especially  true  of  cow-hair.  The  walls  of  the 
medullary  cells  are  generally  very  thin  and  indistinct,  and  the  contents 
consist  of  finely  granular  masses,  air,  and,  in  the  case  of  colored  hairs,  of 
pigment  granules. 


Fig.  62. — Wool  Fibers  showing  Pigmented  Medulla. 


PIGMENTATION  OR  COLOR  97 

The  medulla,  as  a  rule,  is  more  developed  in  beard-hairs  than  In  wool- 
hairs,  and  more  in  coarse  grades  of  wool  than  in  the  finer  qualities.  There 
also  appears  to  be  more  or  less  relation  between  the  breed  of  the  wool  and 
the  morphological  characteristics  of  the  medullary  cells,  although  this  is  a 
subject  which  as  yet  has  been  but  little  studied.  At  times  the  medullary 
cells  exhibit  but  little  difference  from  those  of  the  cortical  layer,  and  these 
two  portions  of  the  fiber  become  continuous  in  their  appearance;  that 
is  to  say,  no  line  of  demarcation  can  be  drawn  between  the  medulla  and 
the  surrounding  cortical  layer. 

Usually  the  medulla  consists  of  a  continuous  axial  cylinder  of  cells, 
though  at  times  the  continuity  may  be  interrupted,  resulting  in  isolated 
cells  or  groups  of  cells,  forming  the  so-called  "  medullary  islands."  The 
function  of  the  medulla  is  to  provide  the  living  fiber  with  an  inner  canal 
for  the  flow  of  juices  whereby  it  receives  nourishment  for  its  growth. 
It  also  adds  much  to  the  porosity  of  the  fiber,  forming  a  capillary  tube 
whereby  the  latter  may  absorb  solutions  of  various  kinds,  such  as  dye- 
stuffs,  different  salts,  etc.,  allowing  these  to  gradually  permeate  through 
the  cortical  layer  as  well.  The  epidermal  layer  of  scales  is  rather  impervious 
to  the  transpiration  of  solutions,  and  only  permits  of  their  entrance  into 
the  fiber  at  the  joints  of  the  scales,  so  it  may  be  seen  that  the  medulla  of 
the  fiber  becomes  an  important  adjunct  in  the  chemical  treatment  of  wool 
in  the  processes  of  mordanting,  dyeing,  and  bleaching.  It  might  also  be 
noted,  in  this  connection,  that  the  epidermal  scales  become  but  slightly, 
if  at  all,  dyed  when  various  coloring  matters  are  applied  to  the  fiber,  but 
remain  colorless  and  translucent.  Hence  it  may  be  readily  understood 
that  if  two  samples  of  wool  are  dyed  simultaneously,  the  one  consisting 
of  fibers  having  small  and  open  scales,  while  the  other  has  a  thick  and 
highly  resistant  epidermis,  the  resulting  color  on  the  two  samples  will 
have  a  different  quality  or  tone,  due  to  the  influence  on  the  latter  of  the 
uncolored  and  translucent  scales.  In  wools  where  this  influence  is  very 
marked  it  is  almost  impossible  to  obtain  rich  and  full  shades  of  color, 
due  to  the  transparency  and  luster  of  the  surface,  which  allows  of  con- 
siderable white  light  being  refracted  through  the  fiber  along  with  the 
reflected  color.  This  also  explains  the  well-known  fact  that  the  longitudinal 
surface  of  the  fiber  in  many  cases  presents  a  different  tone  of  color  than 
the  cut  ends,  the  latter  usually  being  richer  and  deeper  in  tone;  as  may  be 
noticed  in  cut-pile  fabrics,  such  as  occur  in  rugs,  plushes,  etc. 

In  some  cases  the  epidermal  layer,  instead  of  being  highly  translucent, 
is  opaque  and  white;  this  is  true  of  many  varieties  of  coarse  wool-hairs, 
and  such  fibers  as  cow-hair,  etc.  In  such  instances  the  dyed  fiber  will 
lack  liveliness  of  tone  and  appear  rather  dead  and  flat. 

10.  Pigmentation  or  Color. — The  medullary  cells  frequently  contain 
pigment  matter,  either  continuously  or  in  isolated  cells;  and  this  may 


98  PHYSICAL  STRUCTURE   AND   PROPERTIES   OF  WOOL 

occur  even  in  fibers  usually  classified  as  white  wool.  According  to  Bow- 
man (Structure  of  the  Wool  Fiber,  p.  267)  the  pigment  occurring  in  sheep's 
wool  has  the  following  composition: 

Percent 

Carbon 55.40 

Hydrogen 4 .  25 

Nitrogen 8 .  50 

Oxygen 31 .  85 

Sometimes  the  pigment  permeates  not  only  the  medulla,  but  also  the 
cells  of  the  cortical  layer,  in  which  case  the  fiber  as  a  whole  appears  colored. 
To  this  class  belong  the  variously  colored  wools,  ranging  from  a  light 
brown  to  almost  a  black.  The  hair  of  camels,  goats,  and  other  animals 
is  also  more  or  less  colored,  and  to  a  much  more  general  extent  than  sheep's 
wool. 

The  natural  coloring  matter  is  contained  particularly  in  the  fibrous 
and  marrow  cells  in  a  granular  form.  In  the  marrow  cells  these  granules 
are  generally  crowded  together,  whereas  in  the  fibrous  layer  they  are  in 
long  rows  (Hohnel).  Slightly  colored  fibers  show  the  walls  as  almost 
colorless.  On  the  other  hand,  heavily  colored  fibers  have  the  walls  of  the 
cells  also  impregnated  with  coloring  matter,  while  in  artificially  dyed 
wools  the  dyestuff  is  always  seen  in  the  walls,  these  being  uniformly 
colored.  In  the  case  of  artificially  dyed  wools,  therefore,  the  lumen 
disappears;  whereas  with  naturally  colored  wools  and  hairs  this  is  gener- 
ally distinct  through  the  coloring  matter.  Consequently  naturally  colored 
wools,  by  reason  of  the  parallel  arrangement  of  the  granules  of  coloring 
matter,  appear  distinctly  striated,  which  is  never  the  case  with  artificially 
dyed  fibers. 

According  to  McMurtrie  (Examination  of  Wools)  the  idea  advanced  by 
some  German  authorities  that  the  presence  of  the  pigment  canal  in  the 
fibers  has  a  serious  effect  upon  their  strength  is  not  true.  McMurtrie 
states:  "  We  find  it  almost  peculiar  to  the  Cots  wold  breed,  so  far  as  our 
examinations  have  extended,  though  Bohm  and  others  say  it  belongs  to 
all  animals  covered  with  fibers  tending  to  the  hairy  type.  We  have  seen 
only  traces  of  it  in  the  Lincoln  wool,  however,  and  none  whatever  in  the 
wool  of  the  pure  Merinos  and  Downs.  In  the  Oxforddown  wools  it  is 
naturally  present,  and  is  another  evidence  of  the  origin  of  the  breed. 
It  is  not  always  confined  to  a  single  column  or  canal,  nor  does  it  always 
extend  throughout  the  entire  length  of  the  fiber  containing  it,  for  it  fre- 
quently occurs  in  detached  masses  in  the  center  of  the  fiber,  or  distributed 
through  nearly  the  whole  of  the  fibro-cellular  tissue.  This  refers  only  to 
the  white  pigment,  which  alone  we  have  had  an  opportunity  to  study. 
The  colored,  black,  or  brown  pigments  are  not  so  confined,  and  differ  in 


KEMPY   WOOL 


99 


character,  being  distributed  through  the  entire  mass  of  the  fibro-cellular 
tissue.  Since  it  seems  to  affect  neither  the  strength  nor  the  elasticity  of 
the  fiber,  so  far  as  we  have  been  able  to  determine,  the  principal  interest 
it  may  have  will  depend  upon  the  fact  that  it  is  peculiar  to  the  long-wool 
breeds,  principally  the  Cotswold,  and  entirely  wanting  in  pure  Merinos. 
Taken  in  connection  with  the  diameter  of  the  fiber  and  the  forms  of  the 
scales,  it  must  assist  in  the  determination  of  the  purity  of  the  blood  of  the 
animal  under  consideration.  If  a  fiber  containing  the  pigment  canal  be 
treated  with  a  strong  solution  of  potassium  or  sodium  hydroxide,  and 
with  the  aid  of  heat 
it  gradually  disinte- 
grates, the  fibro-cellu- 
lar tissue  is  completely 
broken  down  and 
many  of  the  cells  dis- 
solved, while  the  cells 
constituting  the  pig- 
ment column  or  canal 
remain  intact.  By 
longer  action  of  the 
solvent  they  are  sep- 
arated from  each  other, 
and  upon  agitation 
caused  by  pressure 
upon  the  cover  glass 
they  separate  and  be- 
come distributed  in- 
dependent of  each 
other  through  the  sur- 
roimding  mass.  We 
then  find  them  to 
consist     of     irregular 

masses,  in  many  cases  angular,  in  some  cases  rounded,  and  generally 
lined  or  filled  with  granular  matter  of  which,  as  already  stated,  the  true 
nature  has  never  been  determined." 

11.  Kempy  Wool. — Frequently,  through  disease  or  other  natural 
causes,  the  medulla  of  the  wool  fiber  is  imperfectly  developed  (Fig.  64), 
or  the  scales  of  the  epidermis  are  cemented  together,  in  consequence  of 
which  the  wool  will  not  absorb  solutions  readily,  and  hence  will  not  be 
dyed  (or  mordanted)  at  all,  or  only  slightly.  These  fibers,  which  are 
known  as  kemps,  will  occur  through  the  mass  of  the  wool  as  und3'ed 
streaks,  and  will  give  the  yarn  or  fabric  a  speckled  appearance.  Kempy 
wool  is  said  to  be  due  to  undue  exposure  of  the  sheep  and  to  bad  feed- 


FiG.  63.— Pigment  Canal  in  Cotswold  Wool  Fiber.  Pre- 
pared by  Treating  with  Ammonia,  then  Sulfuric  Acid 
and  Mounting  in  Water. 


100 


PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  WOOL 


ing.  It  is  also  more  noticeable  in  wools  grown  in  mountainous  regions. 
Kempy  wool  should  not  be  used  in  fabrics  intended  to  be  dyed  a  solid  color. 
For  blankets,  Scotch  tweeds,  horse-rugs,  mantle  cloths,  and  the  like,  the 
occurrence  of  kempy  fibers  in  the  wool  is  not  an  especial  drawback.  Not 
only  may  this  condition,  however,  be  brought  about  by  natural  causes, 
but  it  may  at  times  be  the  result  of  improper  manipulation  during  manu- 
facturing processes.  According  to  Bowman,  kemps  have  a  dense  appear- 
ance, the  cellular  character  being  entirely  obliterated,  the  fiber  assuming 
the  appearance  of  an  ivory  rod  without  any  internal  structure  being  visible. 


Fig.  64. — Kempy  Wool  Fibers. 


Kempy  fibers  are  always  much  thicker  than  the  rest  of  the  wool  among 
which  they  grow,  and  the  medulla  or  central  portion  of  the  kemp  is  quite 
thick. 

12.  Pulled  Wool. — There  is  a  certain  class  of  wool  known  in  trade  as 
pulled  wool,  also  known  as  tanners'  wool  and  glovers'  wool.  This  is  obtained 
from  the  pelts  of  slaughtered  sheep,  and  is  usually  removed  from  the  skin 
by  the  action  of  lime,  the  fibers  being  pulled  out  by  the  roots.  In  the 
process,  the  medulla  becomes  stopped  up  with  solid  insoluble  particles  of 
lime,  which  is  also  true  of  the  end  pores  of  the  cortical  layer  and  the  joints 
of  the  scales.  As  a  consequence,  the  fiber  is  very  difficult  to  impregnate 
with  solutions,  and  will  remain  more  or  less  completely  undyed.     This 


PHYSICAL  PROPERTIES 


103 


non-porous  character  is  also  enhanced,   perhaps,  by  tl. 

fiber  does  not  possess  a  freshly  cut  end,  but  still  retains  i^^'  O"'^^®^- 

is  more  or  less  rounded  off  and  closed  by  the  coagulation  ar. 

of  the  juices  in  the  hair  follicle.  ^ches  Test. 

Pulled  wool  is  also  known  as  skin  wool  or  slipe  wool.     Bt 

lime  method  of  treating  pulled  wool,  there  is  also  the  so-called  sO 
process,  which  has  the  advantage  of  not  injuring  the  fiber  as  mu 
the  lime  method.     The  best  method,  however,  is  the  sodium  sulfide  pro 
of  treatment,  as  this  leaves  the  fiber  in  a  rather  good  condition.     Puh 
wool  is  largely  employed  for  blending  with  fleece  wool  or  shoddy. 

13.  Physical  Properties. — In  its  physical  properties,  the  wool  fiber 
varies  within  large  limits,  depending  on  the  breed  and  quality  of  the 


a^^y^lP^aJll^^'Mw^palwj^8)!li^!(gi^wy^-lw 


nJituiimimm 


^-, 


■  fa»- k.^.-.n.^,.  ||,||-'ii-giynn--'Tfia| 


Fig.  65. — Showing  Extreme  Variations  in  Diameter  of  Wool  Fibers.     (X550). 


sheep,  and  also  the  diameter  of  the  fiber  and  the  part  of  the  fleece  from 
which  it  was  derived.  The  strength  of  wool,  and  of  animal  hairs  in  gen- 
eral, is  due  to  the  peculiar  structure  of  the  fiber.  In  the  first  place,  the 
external  sheath  of  horny  tissue  of  flattened  cells  which  take  the  form 
of  scales,  offers  considerable  resistance  to  crushing  strains,  and  are  also 
locked  rather  firmly  together  in  the  direction  of  the  length  of  the  fiber; 
this  has  a  tendency  to  resist  any  diminution  in  the  diameter  of  the  fiber 
which  would  be  felt  when  the  latter  is  stretched.  Then,  too,  the  internal 
cortical  cells  of  the  fiber  are  so  arranged  as  to  present  a  very  firm  structure, 
being  firmly  interlaced  together,  consequently  they  offer  considerable 
resistance  to  rupture.  It  has  been  noticed  by  a  microscopical  examination 
of  a  broken  fiber  that  the  cells  themselves  are  never  ruptured,  but  only 
pulled  apart  from  one  another;  this  is  evidence  that  the  cell- wall  is  of  a 
strong  texture.     The  latter  is  probably  formed  of  a  continuous  tissue 


102 


PHYSICAL  STRUCTURE   AND   PROPERTIES   OF  WOOL 


which  is  less  than  0.0002  in.  in  thickness,  as  under  the  highest  powers  of 
the  microscope  it  exhiljits  no  evidence  of  structural  elements. 

14.  Strength  and  Elasticity. — Bowman  gives  the  following  table, 
which  records  the  average  results  of  a  number  of  experiments  on  the 
strength  and  elasticity  of  the  wool  fiber: 


Wool. 

Tensile  Strength, 
Grams. 

Elasticity, 
Percent. 

Diameter, 
Inch. 

Human  hair 

106.0 

33.0 

31.0 

28.0 

5.9 

3.2 

2.5 

38.0 

9  7 

36.6 
28.4 
27.3 
27.0 
26.8 
33.5 
27.5 
29.9 
24.2 

0  00332 

Lincoln  wool 

0.00181 

Leicester 

Northumberland 

Southdown  wool 

0.00164 
0.00149 
0.00099 

Australian  merino 

0.00052 

Sa.xony  merino 

Mohair 

Alpaca 

0.00034 
0.00170 
0.00053 

It  is  interesting  to  compare  these  figures  of  tensile  strength  for  equal 
cross-sections  of  fiber.  As  the  cross-section  varies  with  the  square  of  the 
diameter,  by  taking  the  ratio  of  the  latter  numbers  and  multiplying  by 
the  tensile  strength,  a  figure  is  obtained  which  represents  the  tensile 
strength  for  equal  diameters  of  fibers.  In  this  manner  the  following 
table  has  been  calculated,  taking  human  hair  as  the  standard  for  com- 
parison, as  it  has  the  largest  diameter: 

Human  hair 100 . 0 

Lincoln  wool 96 . 4 

Leicester 119.9 

Northumberland 130.9 

Southdown  wool 62 . 3 

Australian  merino 122 . 8 

Saxony  merino 224 . 6 

Mohair 136.: 

Alpaca 358.6 

Cotton  (Egyptian) 201 .8 


It  will  be  noticed  from  this  table  that  Saxony  merino  wool  is  by  far 
the  strongest  of  the  different  grades  of  wool.  It  is  also  interesting  to  note 
that  cotton  is  considerably  stronger  than  the  majority  of  wools. 

Barker  ^  has  given  the  comparative  strength  of  equivalent  yarns  of 
worsted  and  other  fibers,  as  follows: 

1  Jour.  Soc.  Dijers  tfc  Col.,  1905,  p.  36. 


STRENGTH   AND   ELASTICITY 


103 


Yam. 


Tram  silk  (4) 

Ramie  (12) 

Linen  (15) 

American  cotton  (14) 

Viscose  silk  (2) 

Luster  worsted  (9) . . . 
Botany  worsted  (9) . . 


Breaking  Strain,  Ounces. 


1  Inch  Test. 

27  Inches  Test. 

45.0 

40.0 

34.5 

24.5 

29.5 

18.0 

17.0 

13.5 

11.0 

11.0 

9.0 

5.0 

7.5 

3.5 

The  size  of  the  yarn  in  each  case  is  equivalent  to  1/30' s  worsted. 
The  numbers  after  the  name  of  each  yarn  represent  the  turns  per  inch, 
being  the  respective  normal  amount  of  twist  in  each  case.  The  figures 
in  the  first  column  represent  more  nearly,  probably,  the  actual  breaking 
strain;  and  those  in  the  second  column  represent  rather  the  slipping  strain 
of  the  yarn,  and  approximate  more  closely  to  the  true  weaving  strength. 

McMurtrie  gives  the  following  table  of  results,  representing  an 
average  of  a  large  number  of  tests  on  the  tensile  strength  of  various  wool 
fibers : 


Strain  in  Grams. 

Highest. 

Lowest. 

Average. 

Cotswold 

Leicester 

Lincoln  

Southdown 

Oxford   

44.54 
30.00 
36.72 
21.29 
45.15 
11.92 

16.10 
15.50 
15.79 

6.48 
19.15 

3.86 

30.44 
23.70 
25.66 
12.78 
30  43 

Merino 

7.35 

The  following  table  is  also  given  showing  the  relative  resistance  and 
stretch  of  wool  fibers,  representing  a  mean  of  a  very  large  number  of 
individual  tests: 


Permanent  Stretch 
in  Millimeters. 


0.25. 


0.50. 


1.00. 


1 .  50.     2 .  00 


2.50. 


3.00. 


3.50. 


4.00. 


5.00. 


Resistance  in  lbs.  per 
sq.  in 

Total  stretch  in  mm  . 

Resistance  in  lbs.  per 
sq.  in 


21.720 
1.00 


21.233 


22 . 659 
2.00 


24.018 


24 . 527 
3.00 


25.805 
4.00 


25.465 


26.723 


26.677 
5.00 


38.285 


27.911 
6.00 


31.024 


29.416 
7.00 


34.736 


32.439 
8.00 


34 . 804 


35.065 
9.00 


43.157 


36 .  524 


41.300 


104  PHYSICAL  STRUCTURE  AND  PROPERTIES  OF   WOOL 


550000 


500000 


450000 


400000 


350000 


§  300000 


-5  250000 
o 


200000 


150000 


100000 


50000 


Total  SttetclLin  Per  Cents  of  Original  Length 
5  10  '  15  20  25  30  35  40  45 


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Total  Stretch  in  Millimetres 

Fig.  66. — Comparative  Moduli  of  Elasticity  of  Different  Wools. 


STRENGTH  AND  ELASTICITY 


105 


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Total  Stretch 
15 

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Per  Cents  of  Original  Lengtli 
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Total  Stretch  in  Per  Cents  of  Original  Length 

Fig.  67. — Comparative  Moduli  of  Wool,  Iron  and  Steel. 


40 


45 


106 


PHYSICAL   STRUCTURE   AND   PROPERTIES   OF   WOOL 


McMurtrie  gives  the  preceding  diagrams  (see  Figs.  66  and  67)  showing 
the  comparative  modiiH  of  elasticity  of  various  kinds  of  wool  fibers,  also 
showing  the  comparison  of  wool  fibers  with  iron  and  steel. 

15.  Length  and  Fineness  of  Staple. — In  length,  the  wool  fiber  varies 
between  large  limits,  not  only  in  different  sheep,  but  also  in  the  same 
fleece.  Generally  speaking,  the  length  may  be  taken  as  being  between 
1  and  8  ins.  The  diameter  of  the  fiber  is  also  very  variable,  even  in  the 
same  fleece,  but  may  be  taken  as  averaging  from  0.0018  to  0.004  in. 
According  to  Hohnel,  the  diameter  of  sheep's  wool  varies  from  10  to 


Fig.  68. — Wool  Combing  Machine  for  Preparing  Tops.     (Noble.) 


100  microns  and  according  to  Cramer,  the  thickness  of  the  hairs  from 
one  and  the  same  fleece  may  vary  from  12  to  85  microns.  According  to 
Barker,  the  finest  wool  has  a  diameter  of  1/2000  to  1/3000  in.  while 
coarse  Algerian  wools  may  rise  to  maximum  diameter  of  1/275  in.  Dif- 
ference in  fiber  diameter  of  wool  forms  an  important  source  of  the  varied 
and  composite  results  realised  in  woven  manufactures.  For  certain 
descriptions  of  cloth,  such  as  face-finished  textures,  botany  worsteds  and 
cashmeres,  wools  having  a  fine  diameter  are  selected;  for  tweeds,  wools 
of  a  coarser  fiber  are  used ;  and  for  luster  goods,  wools  of  a  regular  external 
structure,  and  of  a  small  or  medium  diameter,  are  required,  according 


LENGTH   AND   FINENESS  OF   STAPLE  107 

to  the  quality  of  the  fabric  intended.  Between  the  finest  grown  wools 
with  an  average  diameter  of  1/2400  in.  and  the  thick-haired  wools  with 
an  average  diameter  of  1/500  in.,  there  are  numerous  and  complex  grada- 
tions m  fiber  diameter  (see  Fig.  65). 

According  to  their  length  of  staple,  wool  fibers  are  graded  into  two 
classes:  tops  and  noils.^  The  former  includes  the  longer  stapled  fibers, 
which  are  combed  and  spun  into  worsted  yarns,  to  be  manufactured  into 
trouserings,  dress-goods,  and  such  fabrics  as  are  not  fulled  to  any  extent 
in  the  finishing.  The  latter  class  consists  of  the  short-stapled  fibers, 
which  are  carded  and  spun  into  woolen  yarns  to  be  used  for  weft  and  all 
classes  of  goods  which  are  fulled  more  or  less  in  the  finishing  operations, 
where  a  felting  together  of  the  fibers  is  desired.  On  comparing  worsted 
and  woolen  yarns,  it  will  be  noticed  that  the  former  are  fairly  even  in 
diameter  and  the  individual  fibers  lie  more  or  less  parallel  to  each  other, 
whereas  in  woolen  yarns  the  diameter  is  very  uneven,  and  the  fibers  lie 
in  all  manner  of  directions. 

In  the  distinction  between  woolen  and  worsted  yarns  and  fabrics, 
it  is  interesting  to  note  that  even  in  remote  times  the  Romans  had  two 
distinct  types  of  fabrics,  known  respectively  as  "trita"  and  "densa"; 
the  former  being  a  thin,  flimsy  cloth  made  from  long-fibered  wools  and  spun 
into  fine  threads,  and  consequently  resembling  the  worsteds  of  to-day; 
the  latter  fabric  corresponded  to  our  woolen  goods,  being  a  closely  woven 
felted  fabric  spun  from  shorter  and  coarser  wools.  The  object  in  worsted 
manufacture  is  to  keep  the  fibers  in  the  yarns  as  straight  and  as  parallel 
as  possible,  and  free  from  lumps  and  irregularities,  consequently  the  wools 
employed  have  to  be  thoroughly  classified  and  sorted.  Worsted  yarns 
are  also  spun  to  much  finer  counts  than  woolen  yarns,  and  consequently 
worsted  fabrics  are  usually  of  lighter  weight  than  wool  goods.     Woolen 

^  Noils  consist  of  the  short  fiber  removed  from  wool  during  the  operation  of  combing. 
Naturally  there  are  many  classes  of  noils,  depending  on  the  character  of  the  wool 
used.  In  length  noils  vary  from  about  2  ins.  (hair  noils)  to  under  5  in.  (botany  noils). 
As  noils  are  short  they  are  suitable  only  for  woolen  yarns  and  felting  purposes;  they 
will  also  contain  the  other  impurities  combed  out,  which  consist  mostly  of  vegetable 
matter;  consequently  mostly  noils  have  to  be  carbonised  before  carding.  Cape  noil 
is  probably  the  most  valuable  on  account  of  its  fine  white  color;  it  is  used  in  making 
woolen  fabrics,  shawls,  blankets  and  hats.  Botany  noil  is  also  valuable,  and  though 
short  is  fine  in  fiber  and  quite  white;  it  also  possesses  good  milling  properties.  Cross- 
bred noils  are  of  lower  quality;  the  fiber  is  longer,  smoother  and  stiffer  and  is  not  so 
satisfactory  for  spinning.  The  luster  is  generally  good,  but  the  color  is  yellowish 
and  the  milling  properties  poor.  The  best  qualities  of  noils  are  used  in  hats  and  blankets 
while  the  lower  grades  are  blended  with  mungo  and  shoddy  for  low-grade  woolen. 
They  are  also  used  in  the  making  of  carpet  yarns  where  their  luster  is  valued.  Mohair 
noils  are  very  lustrous  and  soft  and  silky,  but  have  poor  felting  properties  and  are 
difficult  to  spin.  They  are  used  in  cheap  woolens  and  carpet  yarns,  and  certain  grades 
are  used  for  stuffing  mattresses  and  the  like. 


108 


PHYSICAL  STRUCTURE   AND   PROPERTIES   OF   WOOL 


dress-goods,  for  example,  seldom  run  below  10  ozs.  per  yd.  (54  in,  width), 
while  worsted  fabrics  may  run  as  low  as  4  ozs.  per  yd.  for  the  same 
width.  On  the  other  hand,  worsted  fabrics  are  seldom  made  of  over 
24  ozs.  per  yd.  weight,  while  woolen  goods  (such  as  overcoatings)  may 
weigh  as  high  as  40  ozs.  i>er  yd. 

16.  Testing  Wool  Tops.— E.  W.  Tetley  {Textile  Manufacturer)  gives' 
the  following  method  of  testing  wool  tops  for  quality  of  fiber.  A  practiced 
eye  can  very   accurately  distinguish  the  different  qualities.     The  best 


Fig.  69. — Illustrating  Woolen  Yarn  Manufacture:  (1)  Greasy  cross-bred;  (2)  Scoured 
and  dyed;  (3)  Wool  blend;  (4)  Passed  through  Fearnought  machine;  (5)  Scribbled; 
(6)  Carded  slabbing;   (7)  Mule  spun  yarn.     (Tetley.) 


thing  to  do,  however,  is  to  procure  a  standard  range  of  tops  of  guaranteed 
quality,  from  a  first-class  comber,  and  use  them  as  a  fixed  standard  again? 
which  any  new  qualities  may  be  tested.  To  make  a  good  spin,  it  is 
imperative  that  a  top  should  possess  uniformity  in  length  of  fibers.  A 
simple  method  of  ascertaining  the  proportion  of  long,  medium,  and  short 
fibers  in  a  top  is  as  follows: 

The  top  is  taken  between  the  finger  and  thumb  of  the  right  hand, 
and  the  base  of  the  left  hand  placed  firmly  on  the  sliver,  at  just  such  a 
distance  away  that  by  pulling  the  "  top  "  with  the  right  hand  the  fibers 


BLENDING  OF  WOOL  IN  MANUFACTURING 


109 


separate,  and  a  "  draw  "  fs  thus  made.  The  fringe  will  then  be  of  the 
longest  fibers.  A  black  board  or  cloth  is  required.  The  base  of  the  left 
hand  is  then  placed  on  the  fringe  of  the  "  draw,"  and  the  same  operation 
repeated,  thus  making  a  ''  draw  "  of  the  longest  fibers.  This  is  further 
repeated,  the  lengths  of  the  '*  draws  "  becoming  shorter  and  shorter,  until 
the  original  "  draw  "  is  finished,  when  the  different  lengths  of  the  fibers  in 
the  top  will  be  ranged  side  by  side  on  the  black  ground,  and  the  proportion 
of  each,  as  well  as  the  thickness,  can  be  readily  seen  (Fig.  70). 


Fig.  70. — Illustrating  Analysis  of  Tops  for  Uniformity  and  Quality.  Cross-lines  =  1 
in.  apart;  Longest  =  7  to  8  Ins.;  Shortest  =  4  ins.;  Bulk  =  6^  ins.;  Approximate 
percentage  is  8  ins.  =  20%;  7  ins.  =30%;  6  ins.  =20%;  5^  ins.  =  10%;  5  ins.= 
10%;  4  ins.  =  10%.     (Tetley.) 


17.  Blending  of  Wool  in  Manufacturing. — The  blending  of  different 
grades  and  varieties  of  wool  is  an  operation  requiring  great  skill  and 
judgment.  It  requires  a  thorough  knowledge  of  how  the  fibers  will 
combine  with  each  other,  and  the  cost  must  be  adjusted  to  a  prescribed 
amount  with  a  very  small  margin  for  error.  The  mixture  may  consist  of 
mohair,  camel-hair,  shoddy,  mungo,  extract,  and  noils  of  all  descriptions, 
as  well  as  cotton  and  silk  waste,  but  the  whole  must  be  so  blended  that 
no  particular  fiber  stands  out  prominently,  or  the  result  will  be  unsatis- 
factory. The  length  of  the  staple  is  an  all-important  item,  since  it  affects 
the  conditions  of  mixing  proportions  very  much  more  than  the  weight,  and 
will  in  itself  completely  change  the  character  and  appearance  of  yarn 
or  cloth  made  from  it.  Short  wools  are  best  adapted  for  blending,  ^s 
mixtures  either  of  different  colors  or  of  qualities.  Those  of  long  staple  are 
difficult  to  mix  with  short  fibers,  and  tend  to  appear  on  the  surface  of  the 
cloth  when  manufactured,  besides  requiring  to  be  broken  up  in  the  carding. 
Imperfect  blends  result  in  streaky  yarns.     The  streakiness  may  not  be 


no 


PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  WOOL 


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BLENDING   OF  WOOL  IN   MANUFACTURING  111 

visible  to  the  eye  if  the  colors  are  the  same,  but  it  will  show  in  the  manu- 
factured article.  The  nearer  the  fibers  approach  each  other  in  length  of 
staple  the  simpler  is  the  blending. 

The  theory  of  blending  can  never  be  put  down  in  formula,  or  conducted 
on  hard  and  fast  lines,  since  the  materials  vary  so  much  that  nothing  but 
long  experience  can  be  trusted,  while  a  small  difference  in  cost  may  make 
all  the  difference  between  a  profit  and  a  loss.  The  various  bodies  used 
for  making  blends  may  be  briefly  described  as  follows:  Shoddy  is  wool 
recovered  from  fairly  long-stapled  material,  which  has  not  been  milled. 
Mungo  is  the  recovered  fiber  from  cloths  which  have  been  heavily  milled 
or  felted;  on  this  account  mungo  is  ill  adapted  for  working  up  into  yarn 
alone,  and  is  usually  mixed  with  something  with  a  longer  staple,  or  with 
cotton,  and  is  commonly  made  up  into  low  counts  of  weft  yarns.  Having 
once  been  through  the  felting  process,  mungo  fibers  have  lost  much  of  their 
felting  capacity  owing  to  their  surface  scales  being  more  or  less  damaged 
by  disintegration,  and  as  mungo  is  a  very  short  fiber  it  requires  careful 
judgment  on  the  part  of  the  blender  to  know  what  class  of  material  will 
best  go  along  with  it.  For  making  cloths  with  a  fine,  dense,  mossy  nap, 
mungo  answers  extremely  well,  but  requires  some  binding  material  along 
with  it  to  compensate  for  its  shortness  of  fiber.  Extract  wool  is  that 
produced  from  rags  which  have  contained  cotton  or  vegetable  matter 
which  has  been  removed  by  carbonising  with  acid  before  the  rags  were 
pulled. 

The  best  cotton  for  a  woolen  blend  is  the  rough  Peruvian,  which 
strongly  resembles  wool  in  being  long,  rough  and  curly.  It  goes  fre- 
quently by  the  name  of  vegetable  wool,  and  might  easily  deceive  anyone 
but  an  expert.  In  the  manufacture  of  merino  yarns  it  is  extensively  used, 
and  in  addition  to  lessening  the  cost  of  manufacture  it  confers  strength 
and  luster,  besides  reducing  the  tendency  of  the  wool  to  shrink. 

Wool  noils  are  the  short  fibers  separated  during  the  process  of  combing, 
and  these,  being  pure  new  wool,  form  the  best  and  most  expensive  materials 
in  a  woolen  blend.  Camel-hair  noils  are  the  short  fibers  from  camel's  hair. 
The  hair  consists  of  fine  yellowish  brown,  curly  fibers,  mixed  with  dark 
brown,  coarse  body  hairs  about  2  ins.  long.  When  mohair  figures  in  a 
blend  it  is  commonly  as  mohair  noils,  which  are  the  short  fibers  from  the 
hair  of  the  Angora  goat,  and  the  term  mohair  is  rather  expansive,  as  it 
covers  the  fleeces  of  a  large  number  of  Angora  crosses.  Its  color  is  usually 
white,  more  rarely  gray,  and  the  fiber  has  a  fine,  curly  texture  of  high 
luster,  and  an  average  length  of  5  to  6  ins. 

Alpaca  noils  are  the  short  fibers  from  the  combing  of  alpaca  wool. 
This  group  embraces  the  llama,  the  vicuna,  and  the  guanaco,  all  of  which, 
however,  are  less  important  than  the  alpaca  from  the  fiber  point  of  view. 
For  fancy  yarns  silk  noils  are  used  in  combination  with  wool.     These 


112  PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  WOOL 

are  the  short  waste  obtained  from  combing  or  carding  spun  silk.  Both 
silk  and  cotton  must  be  entered  into  a  woolen  blend  only  after  the  wool 
fibers  have  been  oiled.  The  reason  for  this  is  that  if  the  oil  comes  directly 
into  contact  with  either  silk  or  cotton  it  prevents  the  fibers  from  opening 
out  freely  during  the  carding  process.  Skin  wool,  or  pulled  wool,  which, 
as  previously  stated,  is  that  taken  from  the  pelts  of  dead  animals,  has 
generally  to  be  blended  with  other  and  better  grades  of  wool. 

The  mixing  of  a  blend  is  done  by  carefully  building  up  a  stock  of  the 
raw  material  on  the  floor  of  the  mixing  room,  placing  the  different  fibers 
in  thin  layers  one  on  top  of  another.  For  example,  in  a  mixture  of  wool, 
cotton,  and  shoddy,  a  layer  of  wool  a  few  inches  thick  is  first  laid  down, 
covering  some  square  yards  of  the  floor.  Over  this  an  even  layer  of  a  few 
inches  of  cotton  is  placed,  followed  by  a  similar  layer  of  shoddy,  and  these 
successive  layers  are  repeated  and  leveled  up  by  the  use  of  long  rods,  so 
that  a  pile  two  yards  high  is  often  reached,  covering  an  area  of  many 
square  yards,  since  the  larger  the  mixing  the  more  uniform  will  be  the 
fabrics  produced  from  it.  When  great  extremes  in  fiber  length  have  to 
be  mixed,  some  medium  lengths  should  be  present,  so  as  to  unite  them 
properly.  In  a  case  of  this  sort  the  order  of  mixing  would  be  the  short 
and  medium  first,  then  a  blending  of  this  with  the  longer  fibers.  Or, 
supposing  three  lengths  of  staple  to  be  blended,  by  mixing  one-half  of  the 
quantity  of  the  two  lowest  with  the  longest,  and  the  remainder  with  the 
shortest,  two  lots  of  a  mixture  are  obtained  which  can  be  easily  dealt  with 
separately  in  the  mixing  picker,  and  afterward  the  two  can  be  mixed 
together  as  if  dealing  with  only  two  grades  of  material. 

After  building  up  the  pile  layer  by  layer,  the  pulling  for  the  mixing 
picker  is  done  by  taking  armfuls  all  along  one  side,  from  top  to  bottom, 
keeping  the  sides  of  the  pile  perpendicular  by  pulling  straight  down  to 
the  bottom.  Only  by  this  method  can  a  thorough  mixing  be  obtained,  and 
if  a  very  small  quantity  requires  blending  with  a  larger,  the  best  method 
is  to  make  a  temporaiy  mix  of  equal  parts  of  the  two,  and  then  build  this 
up  into  a  stack  with  the  larger  constituent. 

18.  Conditions  Affecting  Quality  of  Wool. — The  quality  of  wool 
obtained  from  sheep  depends  very  largely  on  the  breed,  climatic  conditions 
and  nature  of  the  pasturage  on  which  the  sheep  feed.  Other  conditions 
being  equal,  long  droughty  seasons  in  wool-growing  districts  will  cause 
the  fiber  to  be  much  shorter  than  otherwise. 

Australia  appears  to  possess  the  climatic  conditions  best  adapted  for 
wool-growing.  The  wool  fiber  appears  to  grow  to  best  advantage  in  a 
temperate  climate,  and  when  the  sheep  are  provided  with  dry  foods  and 
pasture  upon  light  soils.  Rain-falls  have  a  great  influence  on  the  wool 
fiber;  fine  merino  wools  being  grown  best  where  the  rain-fall  is  slight, 
while  the  fiber  tends  to  become  coarse  where  the  rain-fall  is  heavy.    Aus- 


CONDITIONS  AFFECTING  QUALITY  OF  WOOL 


113 


tralia  has  a  temperate  climate,  a  light  soil,  and  the  average  rain-fall  is 
only  2  to  3  ins.  With  regard  to  the  nature  of  the  pasturage  it  has  been 
found  that  grass  from  chalky  soils  gives  rise  to  a  coarse  wool,  whereas 
that  from  rich,  loamy  soils  produces  fine  grades  of  wool.  As  a  rule,  the 
sheep  which  yield  the  best  qualities  of  wool  give  the  poorest  quality  of 
mutton.  Utah  wools,  for  instance,  are  harsh  and  stairy  compared  to 
Wyoming  wools.  This  is  due  to  the  alkali  in  the  soil  in  Utah  and  the 
dryness  of  the  climate.  The  alkali  in  the  soil  and  the  effect  it  has  upon  the 
water  which  the  sheep  drink  have  a  tendency  to  take  the  life  out  of  the 
wool  and  weaken  the 
staple.  The  more 
close  and  uniform  the 
fibers  lie,  the  better 
will  be  the  combing 
qualities  of  the  wool. 
The  Utah  wools  in 
this  respect  are  inferior 
to  those  of  Wyoming, 
Idaho,  and  Montana, 
especially  the  wools 
grown  in  southern 
Utah.  In  northern 
Utah  the  wools  are 
longer  than  in  south- 
ern Utah,  but  there 
are  very  few  Utah 
wools,  either  north  or 
south,  which  are  fit  for 
combing.  The  wools  Fig.  71. — Wool  Fibers  Showing  Abnormal  Growth  at  Ends 
of  heaviest  shrinkage  with  Removal  or  Lack  of  Scales. 

generally   come    from 

eastern  Oregon  and  Nevada.  The  degree  of  shrinkage  depends  to 
a  considerable  extent  on  the  season  in  which  the  wools  were  grown. 
A  wet  season  and  long-continued  rains  will  wash  much  dirt  and  dust 
out  of  the  wools,  thus  leaving  them  lighter.  The  wools  of  lightest 
shrinkage  come  from  Virginia  and  Kentucky  and  the  Blue  Grass  region, 
where  medium  wools  are  grown,  where  the  sheep  are  cleaner,  the  range 
better,  and  the  country  hilly,  and  where  comparativel}^  little  sand  and 
dirt  work  their  way  into  the  fleece.  The  shrinkage  of  washed  fleeces 
ranges  from  55  to  35  percent.  Unwashed  Indiana  wools  shrink  38  to  43 
percent.  Missouri  wools  will  shrink  around  43  to  45  percent;  those  of 
Illinois,  45  to  47  percent.  California  wools  shrink  55  to  72  percent,  depend- 
ing on  the  part  from  which  they  come.     The  heaviest  shrinkage  wools 


114  PHYSICAL   STRUCTURE  AND   PROPERTIES   OF   WOOL 

are  in  southern  California,  because  of  the  presence  of  more  sand  and  dirt, 
and  inferiority  of  the  range.  Texas  Spring  wools  shrink  anywhere  from 
64  to  72  percent,  and  the  Fall  wools  58  to  64  percent.  Territory  wools 
shrink  from  55  up  to  73  percent.  Idaho  wools  on  the  medium  order  will 
not  shrink  over  55  percent.  Wyoming  wools  on  the  fine  and  fine  medium 
order  shrink  65  to  72  percent.  The  Montana  wools  shrink  on  the  average 
63  to  69  percent  for  fine  and  fine  mediums,  and  57  to  60  percent  for  medi- 
ums. The  shrinkage  on  Arizona  wools  will  range  from  66  to  73  percent, 
but  they  will  spin  to  finer  counts  than  the  Utah  wools,  and  will  scour 
out  very  white.  In  this  latter  respect  the  Wyoming  wools  are  superior 
to  any  other  grown  west  of  the  Mississippi  River.  The  shortest  wools 
grown  in  America  are  from  California  and  Texas;  they  are  used  principally 
for  felts  and  hats,  though  they  can  also  be  mixed  in  certain  proportions 
with  clothing  wool.  As  the  Territory  wools  are  grown  mostly  in  dry 
climates,  they  will  gain  somewhat  in  weight  on  being  shipped  to  the 
Atlantic  seaboard  and  stored  for  a  few  months.  Utah  wools  will  gain 
about  1  percent,  Montana  wools  about  f  percent,  and  Wyoming  wools 
about  1  percent.  The  wools  from  Ohio  and  other  eastern  States  will 
not  gain  anything;  in  fact,  will  sometimes  show  a  slight  shrinkage. 

Unhealthy  conditions  of  the  sheep  almost  always  influence  the  fiber 
during  that  period  of  its  growth.  If  the  sheep,  for  example,  is  suffering 
from  indigestion,  cold,  lack  of  proper  nourishment,  etc.,  the  fleece  during 
that  time  will  develop  tender  fibers;  when  the  sheep  regains  its  normal 
condition  of  health  the  fiber  becomes  strong  again.  Thus  the  fleece 
may  have  tender  strata  through  it  which  will  considerably  affect  the  fiber 
and  its  uses.  These  tender  spots,  of  course,  render  the  wool  unfit  for 
combing  purposes,  and  it  must  go  into  the  "  clothing  "  class,  and  will 
consequently  sell  for  less  money,  other  things  being  equal.  It  is  no 
great  injury  to  the  wool,  however,  aside  from  spoiling  it  for  combing, 
as  the  wool,  after  it  has  passed  the  tender  spot,  grows  fully  as  well  as 
before  the  sheep  was  ill. 

When  sheep  have  been  afflicted  with  scab,  the  latter  shows  itself  in 
tender  wool  at  the  bottom  of  the  fiber.  The  scab  leaves  a  puslike  sub- 
stance which  adheres  to  the  bottom  of  the  fibers  and  dries  there.  Vermin 
on  sheep  have  an  influence  on  the  wool ;  these  creatures  leave  discolorations 
on  the  fiber  which  cannot  be  removed  by  scouring.  The  wool,  being 
"  off  color,"  does  not  sell  as  well,  and,  moreover,  the  fiber  is  liable  to  be 
tender.^ 

•  The  dipping  of  wool  on  the  sheep's  back  is  almost  a  necessity,  to  overcome  the 
harmful  influence  of  ticks,  lice  and  other  insects  and  vermin,  which  would  tend  to 
produce  scab.  A  good  dip  may  also  lubricate  the  fiber,  giving  it  softness  and  elas- 
ticity, and  may  even  improve  the  color  by  slightly  bleaching  it;  but  many  dips  have 
proved  to  be  harmful  to  the  wool,  making  it  weak  and  brittle,  stunting  its  proper 


INFLUENCE  OF  MANUFACTURING  OPERATIONS 


115 


19.  Influence  of  Manufacturing  Operations  on  Quality  of  Wool. — 
While  the  woolen  manufacturer  is  interested  primarily  in  the  strength  and 
quality  of  the  wool  fiber  as  such  in  the  preparation  of  the  fabric,  the 
consumer  or  user  of  the  fabric  itself  is  more  interested  in  the  strength  and 
quality  of  the  made-up  material.  There  are  many  factors  which  enter 
into  this  phase  of  the  question,  chiefly  depending  on  the  nature  of  the 


Giey 


After 


Scouring 


Lbs 
140 


130 


120 


;;rabbing 
2 


After 


Milling 
4 


Raising 
and 


Dyeing 
and 


Cutting      Pressing 
and 


Cutting     Tentering    Brushing 


Steaming 
9 
140 


130 


60 


1  1                                1                                           1 

1 1 LI 1 

iJJ ^_              _ , L    -  - 

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120 


110 


100 


90 


80 


70 


60 
Lbs. 


Fig.  72. — Influence  of  Finishing  Operations  on  Tensile 

(Midgley.) 


Strength  of  Woolen  Fabrics. 


finishing  processes  as  well  as  the  care  with  which  they  have  been  carried 
out.  It  makes  little  difference  how  fine  in  quality  the  original  wool 
fiber  may  have  been  if  its  good  qualities  have  become  affected  by  the 
various  manufacturing  processes  through  which  the  wool  has  been  carried 
in  the  making  of  the  cloth.  Woolen  fabrics  are  more  likely  to  suffer  than 
worsted  fabrics,  and  it  is  on  the  experience  and  workmanship  of  the 
finisher  that  a  great  deal  depends. 

growth,  and  giving  it  a  bad  color.  Among  the  harmful  dips  may  be  included  hme 
and  sulfur  combinations,  tobacco  mixtures  and  pitch  oil  compositions.  The  most 
satisfactory  dips  are  considered  to  be  arsenical  preparations  and  carbolic  acid  with  oil. 


116 


PHYSICAL   STRUCTURE  AND   PROPERTIES  OF   WOOL 


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INFLUENCE  OF   MANUFACTURING  OPERATIONS 


117 


ILLUSTRATING  THE  LOSS  OF  WEIGHT  INCURRED  DURING  FINISHING 

"WOOLENS" 


Loss  in 

Type  of  Cloth. 

Finish. 

Warp. 

Fining. 

Weight. 

Weight, 
Percent. 

1 

Vicuna 

Heavily  milled 

Woolen  yarn,  low  qual- 
ity 

As  Warp 

2U  oz. 

24 

2 

Trousering 

Clean  finish 

Colored    worsted    and 

Black  woolen,  low 

cotton  twist 

quality 

16  oz. 

17 

3 

" 

" 

Ditto 

Ditto 

16  oz. 

16J 

4 

Mixture  coating 

Tweed  finish 

24  cut  Gala  (mixture), 
44  threads  per  inch 

As  warp 

17  oz. 

10 

5 

2/24    cut    Gala    (mix- 
ture) ,  30  threads  per 
inch 

As  warp 

18  oz. 

10 

6 

Trousering 

Slightly  milled 

30  sk.  colored  woolen, 
good      quality,       68 
threads  per  inch 

As  warp.    64  picks 
per  inch 

17  oz. 

10 

7 

Low  melton 

Heavily  milled 

2/40  cotton,  40  threads 
per  inch 

6  sk.  low  quality, 
60  picks  per  inch 

18  oz. 

27 

8 

Carriage  rug 

Velvet  finish 

2/20  cotton,  18  threads 
per  inch 

Colored  5sk.  wool- 
en,     medium 
quality 

3|  lb. 

20 

9 

Carriage  rug 

Velvet  finish 

Colored    woolen   yarn, 
low  quality 

As  warp 

4  lbs. 

22 

10 

Amazon  dress  fabric 

Milled  and  raised 

1/36  mule  spun  worst- 
ed,   72    threads    per 
inch 

40  sk.  woolen,  fair 
quality,  36  picks 
per  inch 

13 

The  influence  of  various  dyeing  and  finishing  operations  on  the  strength 
of  woven  cloth  is  quite  important,  and  such  influences  are  mostly  due  to 
the  effect  on  the  fiber  of  which  the  cloth  is  composed.  Prof.  E.  Midgley 
{Textile  Manufacturer)  gives  a  plotted  diagram  of  curves  (Fig.  72)  and 
tables  representing  the  influences  of  various  processes  on  the  strength 
of  woolen  cloth. 

To  understand  the  various  factors  which  play  a  part  in  this  matter 
the  following  processes  are  discussed  by  a  practical  finisher  (Textile 
Manufacturer)  in  their  relation  to  their  influence  on  the  quality  of  the 
fabric. 

Overheating. — The  one  cause  of  tenderness  is  overheating  the  goods 
during  the  fulling  operation.  A  certain  amount  of  heat  is  necessary  in 
conjunction  with  the  other  essential  conditions — namely,  pressure,  friction, 
and  the  lubricating  and  softening  agency  of  the  soap  solution, — but  an 
excess  of  heat  is  always  to  be  avoided.  A  fabric  composed  of  good, 
sound  and  strong  woolen  yarn  may  be  considerably  reduced  in  strength 
by  adding  more  weight  than  necessary  to  the  trap  of  the  crimping  box 
in  an  attempt  to  accelerate  the  process.  The  excessive  weight  causcF 
great  pressure  and  friction,  and  as  friction  gives  rise  to  heat,  the  greater 
the  friction,  the  greater  the  possibility  of  overheating  the  fabric.     Heat 


118  PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  WOOL 

may  also  be  generated  to  excess  when  the  fulhng  is  performed  in  too  close 
or  confined  conditions,  and  this  is  most  liable  to  occur  in  hot  or  sultry 
weather,  if  the  necessary  precautions  to  prevent  such  are  not  observed. 
In  the  winter,  or  during  the  cold  weather,  it  often  becomes  necessary,  in 
order  to  commence  the  felting  and  to  perform  the  operation  in  a  reason- 
able time,  to  confine  the  atmosphere  of  the  fulling  mill  by  preventing,  to 
a  considerable  extent,  the  access  of  the  cold  outside  air.  This  is  accom- 
plished by  placing  the  box  cover  over  the  fulling  rollers,  adding  the  lids 
to  the  top  of  the  fuller  and  closing  the  door  of  the  machine  during  the 
fulling  operation;  thus  the  heat  which  is  generated  by  the  continual 
friction  is  confined  to  the  fulling  mill,  and  the  process  is  accelerated. 
Naturally,  in  hot  or  sultry  weather  the  tendency  of  the  atmosphere  is 
to  increase  rather  than  decrease  the  heat  generated  during  the  passage 
of  the  fabric  through  the  machine.  Hence,  it  is  imperative  that  the 
fabric  be  ventilated  as  much  as  possible  to  avoid  overheating,  and  the 
covers  for  the  rollers  and  top  of  the  machine  are  dispensed  with,  and  the 
operation  performed  with  the  door  open  also.  Investigation  seems  to 
prove  that  it  is  not  entirely  the  excess  of  heat  which  causes  tenderness, 
but  rather  the  excess  of  heat  combined  with  friction  and  pressure;  also 
that  the  tenderness  is  not  wholly  due  to  a  weakening  of  threads  composing 
the  fabric.  Considering  the  question  of  heat  first,  there  are  processes — 
namely,  scouring,  dyeing,  and  Ijoiling — in  which  a  fabric  may  undergo 
treatment  at  a  much  higher  temperature  than  that  generated  in  the  fulling 
mill  without  suffering  materially  in  strength,  providing  the  material  is 
of  good  strength  previous  to  treatment  in  these  processes.  Of  the  proc- 
esses mentioned,  it  will  be  observed  that  only  in  the  scouring  does  pressure 
and  friction  take  place  to  any  extent,  and  that  in  an  inferior  degree  as 
compared  with  the  pressure  and  friction  during  the  fulling.  What  appar- 
ently takes  place  as  overheating  occurs  is  this:  The  fibers,  under  the  influ- 
ence of  moisture  and  the  high  temperature,  are  rendered  very  soft  and 
pliable,  yielding  freely  to  the  vigorous  action  which  always  exists  during 
fulling,  and  become  partially  detached  from  the  body  of  the  threads  in 
considerable  quantities,  weakening  the  threads  in  consequence.  Running 
the  goods  too  dry  during  the  fulling  also  frequently  results  in  a  light 
weakening  of  the  fabric,  not  sufl^icient,  however,  to  designate  a  piece  as 
being  tender.  The  lack  of  lubrication  causes  chafing,  and  waste  in  the 
form  of  flock  is  much  in  evidence  on  the  guide  board  and  on  the  trap  of  the 
crimping  box  immediately  behind  the  fulling  rollers. 

Raising  or  Dressing. — To  avoid  tenderness  during  raising  is  one  of  the 
chief  points  which  the  finisher  must  bear  in  mind,  during  both  the  wet 
and  dry  processes,  and  if  the  desired  smartness  cannot  be  satisfactorily 
obtained  without  endangering  the  strength  of  the  fabric,  then  the  appear- 
ance to  a  certain  extent  becomes  only  a  secondary  consideration,     A 


INFLUENCE   OF  MANUFACTURING  OPERATIONS  119 

fabric  which  is  known  to  be  weak  previous  to  the  commencement  of  raising 
(wet  or  dry)  must  be  treated  with  special  care,  the  teasels  used  must  be 
weak  or  of  only  moderate  strength,  and,  above  all,  the  operation  must  be 
of  a  gentle  character.  Tenderness  may  be  caused  as  a  result  of:  (1) 
over-treatment;  (2)  using  teasels  which  are  too  poweiful,  or  when  raising 
on  the  Mozer  increasing  the  speed  of  the  wire  rollers  rashly;  and  (3) 
lack  of  sufficient  moisture.  The  term  ''over-raised"  or  "over-dressed" 
is  invariably  applied  to  any  fabric  which  becomes  tender  during  raising, 
whether  the  actual  cause  is  directly  due  to  over-treatment  or  not.  A 
fabric  which  is  rendered  tender  by  over-raising  generally  conforms  more 
nearly  to  the  desired  requirements — in  wet  raising,  smartness  and  fineness 
of  surface;  and  in  dry  raising,  smartness  and  clearness  of  surface  after  the 
pile  is  removed — than  is  the  case  when  the  strength  is  reduced  by  the  use 
of  strong  work  or  raising  too  dry.  Over-raising  is  due  to  lack  of  proper 
judgment  or  attention  on  the  part  of  the  person  responsible,  whereby  the 
treatment  is  unnecessarily  prolonged,  and  though  the  strength  of  teasels 
or  the  speed  of  the  wire  rollers  on  the  Mozer  is  correct,  and  the  fabric 
sufficiently  damp,  an  excessive  amount  of  fibers  become  detached  from 
the  threads,  which  are  in  consequence  weakened. 

In  order  to  obtain  the  best  results  during  wet  raising  not  only  as  regards 
fineness,  smartness,  and  brilliancy  of  finish,  but  also  to  retain  the  strength 
of  the  material,  a  correct  degree  of  moisture  must  be  maintained  through- 
out the  operation.  Excess  of  moisture  retards  the  process,  particularly 
when  raising  on  a  teasel  gig,  and  the  weak  teasels  which  are  employed  at 
the  commencement  do  little  real  work;  consequently,  the  fabric  is  lacking 
in  fineness  of  surface.  Lack  of  moisture,  however,  is  more  to  be  feared, 
as  the  fibers  when  in  a  dry  condition  are  brittle,  unyielding,  and  more  easily 
broken  and  torn  from  the  threads,  causing  weakness,  and  flyings  or  flocks 
become  more  numerous.  The  cloths  should  be  evenly  cuttled  and  covered 
completely  with  a  wet  linen  wrapper,  and  some  little  time  before  a  fabric 
is  required  for  raising  it  should  be  reversed  to  allow  the  water  to  drain 
evenly  through.  During  raising,  also,  the  lists  should  receive  attention 
and  be  damped  if  required,  and  should  it  be  necessary  to  cuttle  the  cloth 
on  the  scray  before  the  process  is  completed,  it  should  be  covered  with  a 
damp  wrapper  as  previously  stated.  Thin  cloths  in  particular  require 
careful  attention  in  this  respect. 

Roll  Boiling  or  Potting. — Sound,  strong  fabrics  may  receive  as  many 
as  five  or  more  distinct  boils,  each  of  at  least  six  hours'  duration  at  tem- 
peratures from  70°  C.  to  80°  C,  without  any  apparent  loss  of  strength 
when  tested  by  the  usual  methods  in  vogue  in  the  factory.  The  majority 
of  fabrics  required  to  be  roll-boiled  are  of  the  "dressed  face"  varity,  and 
to  guard  against  weakness  during  the  boiling  a  few  precautions  are  neces- 
sary.    In  the  first  place,  the  soft  water  in  which  the  rolls  are  boiled  should 


120  PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  WOOL 

be  slightly  acid;  this  is  not  only  a  safeguard  against  running  colors,  but 
a  prolonged  boiling  in  a  slightly  acid  bath  is  far  less  injurious  to  the  wool 
fibers  than  if  the  bath  is  neutral.  Acetic  is  quite  a  safe  acid  to  employ, 
and  answers  the  purpose  admirably  in  the  proportion  of  1  qt.  of  acid  to 
100  gals,  water.  The  next  and  by  far  the  most  important  step  to  be 
taken  to  prevent  tenderness  is  with  the  rolling  of  the  fabric.  To  obtain 
the  best  results  from  the  roll  boiling  process  as  regards  a  lustrous  surface 
it  is  essential  that  the  fabric  be  rolled  tightly.  Now  it  is  obvious  that 
when  the  rolled  fabric  is  immersed  in  the  boiling  tank,  as  the  individual 
fibers  absorb  the  water  and  thereby  swell  or  attempt  to  swell,  the  roll  of 
cloth  becomes  much  tighter  and  firmer,  and  a  great  strain  results  on  both 
the  warp  and  weft  of  the  fabric,  and  if  the  threads  are  not  of  sufficient 
strength  to  withstand  the  strain,  they  yield,  and  are  thus  further  weak- 
ened, causing  a  tender  cloth.  Microscopic  examination  reveals  the  fact 
that  wool  fibers  treated  in  water  at  high  temperatures  increase  in  diameter 
to  a  greater  extent  than  when  treated  at  the  lower  temperatures.  Con- 
sequently, variation  in  the  temperature  of  the  water  in  which  the  boiling 
takes  place  is  necessary  when  dealing  with  fabrics  inclined  to  be  tender. 
For  if  such  fabrics  are  treated  at  the  higher  temperature,  160°  F.  to 
180°  F.,  then  as  the  individual  fibers  attempt  to  expand,  the  strain  occa- 
sioned may  be  such  as  to  render  the  fabric  tender.  The  temperature  for 
such  goods  should  not  be  higher  than  140°  F.,  for  preference  less,  to  per- 
form the  boiling  with  safety. 

Carbonising. — The  first  process  to  be  considered  where  the  wool  fibers 
may  be  directly  attacked  is  the  carbonising  or  the  steeping  stage  of  the 
carbonising  process,  in  which  the  fabric  is  chemically  treated  to  destroy 
extraneous  vegetable  matter.  Providing  the  solution  of  dilute  sulfuric 
acid  is  used  at  the  correct  strength  there  need  be  no  fear  of  tenderness 
resulting.  The  solution  should  be  at  6°  Tw.,  and  should  not  exceed  this 
standard,  or  the  strength  of  the  fabric  is  placed  in  jeopardy,  as  the  acid 
attacks  the  wool  fibers.  Tenderness  as  a  result  of  the  carbonising  process 
can  only  arise  through  carelessness  or  negligence  in  preparing  the  acid  bath. 

Cutting. — The  only  cause  of  tenderness  during  the  cropping  or  cutting 
operation  is  absolute  carelessness  or  incompetence  on  the  part  of  the 
cutterman,  whereby  the  cutting  portion  is  set  too  near  the  surface  of  the 
fabric,  and  instead  of  only  removing  the  superfluous  fibers,  the  fibers 
composing  the  threads  which  are  uppermost  are  severed,  weakening  the 
fabric  in  consequence.  Fabrics  most  liable  to  injury  in  this  respect  are 
those  which  require  a  close  cropping,  and  as  the  majority  of  worsteds 
require  a  clear  finish,  these  goods  may  be  expected  to  suffer  more  than 
woolens. 


CHAPTER  V 

THE  CHEMICAL  NATURE  AND  PROPERTIES  OF  WOOL 
AND  HAIR  FIBERS 

1.  Composition  of  Raw  Wool. — In  its  chemical  constitution  wool  is 
closely  allied  to  hair,  horn,  feathers,  and  other  epidermal  tissues.  A 
distinction  must  be  made  between  the  fiber  proper  and  the  raw  wool  as 
it  comes  from  the  fleece.  In  the  latter  condition  it  contains  a  large  amount 
of  dirt,  grease,  and  dried-up  sweat  which  have  first  to  be  removed  by  the 
scouring  process  before  the  pure  fiber  is  obtained.^ 

The  following  analysis  by  Chevreul  of  a  merino  wool  shows  the  average 
amount  of  fiber  to  be  obtained  from  raw  fleece  wool: 

Percent. 
Earthy  matter  deposited  by  washing  the  wool  in  water  .     26 .  06 

Suint  or  yolk  soluble  in  cold  distilled  water 32 .  74 

Neutral  fats  soluble  in  ether 8 .  57 

Earthy  matters  adhering  to  the  fat 1 .  40 

Wool  fiber 31 .23 


100.00 


These  figures  are  based  on  wool  dried  at  100°  C;  if  corrected  for  air- 
dry  wool  containing  14  percent  of  moisture,  this  would  give  only  about 
27.5  percent  of  pure  fiber.  Of  course,  the  amount  of  fiber  will  vary  con- 
siderably in  different  qualities  and  samples  of  wools,  but  this  figure  may 
be  taken  as  a  fair  average. 

^  There  is  a  bad  practice  in  some  sheep-raising  districts  of  branding  the  sheep  with 
tar.  Many  efforts  have  been  made  by  manufacturers  to  point  out  to  farmers  that 
irremediable  damage  is  done  to  the  wool  from  the  manufacturing  point  of  view,  as 
this  tar  cannot  be  removed  in  ordinary  scouring  processes,  but  has  to  be  cut  out  of 
the  fleece  as  waste.  Small  pieces  of  tar  left  on  the  wool  cause  immense  damage  in  sub- 
sequent operations,  because  the  fibers  of  the  wool  are  caused  to  adhere  firmly  together 
during  the  opening  operations.  This  method  of  branding  is  entirely  unnecessary,  as 
a  harmless  branding  liquid  is  now  in  existence  which  can  be  easily  scoured  out  in 
ordinary  washing  operations.  A  warning  is  issued  in  regard  to  using  a  branding 
liquid  which  may  have  been  stored  in  a  phosphate  tin,  for  this  causes  the  substance 
to  attack  and  burn  the  wool  and  the  fleece  has  to  be  chpped  from  the  sheep. 

121 


122      CHEMICAL  NATURE  AND  PROPERTIES  OF  WOOL 

Wright  ^  gives  the  following  analyses  of  greasy  wools : 


Constituents. 


Moisture 

Wool-fat 

Other  fatty  matter 
Water  soluble  suint 

Sand,  dirt,  etc 

Pure  wool  fiber. . . . 


Half 
Blood. 


16.90 
16.68 

0.42 
10.30 

3.62 
52.08 


Three-quarter 
Blood. 


19.30 
12.08 

0.74 
12.72 

3.92 
51.32 


Leicester. 


17.97 
8.94 
0.91 

7.81 

5.10 

59.45 


Lincoln. 


17.18 
5.72 
0.96 
2.26 
5.32 

68.56 


Barker  {Encyl.  Brit.)  gives  the  following  list  of  the  yield  in  clean  wool 
of  the  chief  commercial  varieties: 

Yield  in 
Type  of  Wool.  Percent. 

Australian  merino 50 

Cape 48 

South  American  merino 45 

New  Zealand  cross-bred 75 

South  American  cross-bred 75 

English  Southdown 80 

English  Shropshire 80 

English  Lincoln 75 

Mohair 85 

Alpaca 85 

2.  Wool  Grease ;  Cholesterol. — The  fatty  and  mineral  matters  present 
on  the  raw  wool  fiber  consist  on  the  one  hand  of  wool  grease  derived 
from  the  fatty  glands  surrounding  the  hair  follicle  in  the  skin,  and  on  the 
other  hand  of  dried-up  perspiration  from  the  sudorific  glands  in  the  skin. 
The  wool  grease  is  mostly  to  be  found  as  the  external  coating  on  the  fiber 
which  serves  to  protect  it  from  mechanical  injury  and  felting  while  in  the 
growing  fleece.  The  statement  made  in  some  text-books  that  raw  wool 
when  left  in  the  greasy  condition  is  not  attacked  by  moths  is  erroneous. 
The  personal  experience  of  the  author  has  proved  that  raw  wool  is  as  liable 
to  the  depredations  of  insects  as  washed  and  scoured  wool. 

Lack  of  natural  grease  on  the  fibers  of  the  growing  fleece  results  in  the 
production  of  so-called  cotted  fleeces.  In  such  fleeces  the  fibers  have 
grown  in  and  among  eacl  other  on  the  sheep's  body,  so  that  they  form 
a  more  or  less  perfect  mat  of  wool.  These  mats  are  hard  or  soft  according 
to  the  extent  to  which  the  matting  process  has  been  carried  on.  Cotted 
fleeces  occur  mostly  in  sheep  which  have  been  housed;  they  are  seldom 
found  in  the  territories  where  the  sheep  run  on  the  range  and  are  more 
1  Jour.  Soc.  Chem.  Ind.,  1909,  p.  1020. 


SUINT  123 

exposed  and  hardy.  Cotted  fleeces  indicate  a  low  degree  of  vitality, 
and  many  are  to  be  found  in  fleece  wool  from  States  east  of  the  Missis- 
sippi River.  They  may  be  caused  by  sickness  or  a  low  state  of  the  blood, 
or  they  may  be  found  in  an  old  sheep  which  is  giving  out  or  is  run  down, 
which  contributes  to  the  frowsy  condition  of  the  wool.  Cotted  fleeces 
are  unfit  for  combing  purposes,  as  they  have  to  be  torn  apart,  and  fre- 
quently they  are  so  dense  and  hard  that  the  fibers  can  only  be  pulled  apart 
by  the  use  of  special  machinery.  Badly  cotted  fleeces  are  frequently 
used  for  braid  purposes. 

There  is  also  a  small  amount  of  oily  matter  contained  in  the  medullary 
intercellular  structure  of  the  fiber  which  appears  to  have  the  function  of 
acting  as  a  lubricant  for  the  inner  portion  of  the  fiber,  thus  preserving 
its  pliability  and  elasticity. 

Wool  grease  does  not  appear  to  be  a  simple  compound,  but  evidently 
consists  of  several  oils  and  wax-like  compounds.  Its  chief  constituent 
is  cholesterol,  which  appears  to  be  one  of  the  higher  monatomic  alcohols, 
and  is  not  a  glyceride.  Analysis  shows  it  to  have  the  formula  C26H43OH. 
It  is  a  solid  wax-like  substance  which  very  readily  emulsifies  in  water. 
Associated  with  cholesterol  there  is  also  an  isomeric  body  called  isocho- 
lesterol.  Besides  these  solid  waxes,  wool  grease  also  contains  two  fats 
which  have  been  studied  by  Chevreul  to  some  extent.  These  are  described 
as  follows : 

(a)  Stearerin,  a  neutral  solid  fat,  melting  at  60°  C;  contains  neither 
nitrogen  nor  sulfur;  does  not  emulsify  with  boiling  water,  but  emulsifies 
without  saponification  when  boiled  with  caustic  potash  and  water;  it  is 
soluble  in  1000  parts  of  alcohol  at  15.5°  C. 

(b)  Elairerin,  a  neutral  fat  melting  at  15.5°  C;  also  free  from  nitro- 
gen and  sulfur;  it  emulsifies  with  boiling  water,  and  is  saponified  with 
caustic  potash;  it  is  soluble  in  143  parts  of  alcohol  at  15.5°  C. 

3.  Suint. — The  dried-up  perspiration  adhering  to  the  raw-wool  fiber 
is  also  called  suint.  It  consists  principally  of  the  potash  salts  of  various 
fatty  acids,  and  it  is  soluble  in  water,  therein  it  differs  from  wool  grease. 
On  extraction  with  water,  suint  will  yield  a  dry  residue  of  about  140  to 
180  lbs.  for  1000  lbs.  of  raw  wool.  This  on  ignition  will  give  70  to  90  lbs. 
of  potassium  carbonate  and  5  to  6  lbs.  of  potassium  sulfate  and  chloride, 
so  that  the  amount  of  potash  salts  to  be  derived  from  raw  unwashed  wool 
may  be  taken  to  be  about  10  percent  on  the  weight  of  wool. 

Maumene  and  Rogelet  give  the  following  analysis  for  the  inorganic 
constituents  of  suint: 

Percent. 

Potassium  carbonate 86 ,  78 

Potassium  sulfate 6 .  18 

Potassium  chloride 2 .  83 

Silica,  phosphorus,  lime,  iron,  etc 4.21 


124  CHEMICAL  NATURE  AND  PROPERTIES  OF  WOOL 

The  yield,  however,  of  potash  salts  that  may  be  recovered  from  wool 
suint  is  very  variable,  owing  to  the  different  character  and  proportion  of 
the  suint  in  different  lots  of  fleece  wools.  Stirm  {Die  Gespinstfasern,  p.  143) 
gives  the  following  figures  obtained  in  practice  (at  Dohren);  5000  lbs. 
of  raw  wool  gave  142  lbs.  of  raw  potash  salts  having  the  following 
composition : 

Percent. 

Potassium  carbonate 78 . 5 

Potassium  chloride 5.7 

Potassimn  sulfate 2.8 

Sodium  sulfate 4.6 

Insoluble  matter 5.0 

Organic  matter 3.0 

According  to  Marker  and  Schulze  ^  the  ash  of  two  representative 
samples  of  wool  suint  had  the  following  composition: 

Percent.  Percent. 

(I)  (II) 

Potassium  oxide  (KoO) 58.94  63.45 

Sodium  oxide  (Na.O) 2 .  76  Trace 

Calcium  oxide  (CaO) 2.44  2. 19 

Magnesium  oxide  (MgO) 1 .  07  0 .  85 

Iron  oxide  (Fe203) Trace  Trace 

Chlorine  (CI) 4.25  3.83 

Sulfuric  acid  (SO3) 3. 13  3.20 

Phosphoric  acid  (PaOj) 0.73  0.70 

Silicic  acid  (SiOs) 1.39  1.07 

Carbonic  acid  (COo) 25. 79  25.34 

4.  Ash  of  Wool  Fiber. — Besides  the  mineral  matter  existing  in  the 
soluble  suint,  there  is  also  a  small  amount  of  mineral  matter  which 
appears  to  form  an  essential  constituent  of  the  fiber  itself.  It  is  left  as  an 
ash  when  wool  is  ignited,  and  amounts  on  an  average  to  about  1  percent, 
the  majority  of  which  is  soluble  in  water  and  consists  of  the  alkaline 
sulfates.  The  following  analysis  by  Bowman  shows  the  typical  composi- 
tion of  the  ash  of  Lincoln  wool : 

Percent. 

Potassium  oxide 31.1 

Sodium  oxide 8.2 

Calcium  oxide 16.9 

Aluminium  oxide  \  1  o  q 

Ferric  oxide  / 

Silica 5.8 

Sulfuric  anhydride 20 . 5 

Carbonic  acid 4.2 

Phosphoric  acid Trace 

Chlorine Trace 

^Jour.  Praki.  Chem.,  vol.  108,  p.  193. 


COLORING  MATTER  125 

Arsenic  appears  to  be  present  in  nearly  all  samples  of  wool,  even  in 
the  natural  state.  The  arsenic  is  generally  derived  from  the  dips  to 
which  the  sheep  are  subjected.  Even  the  wool  from  a  lamb  whose  mother 
has  been  dipped  a  considerable  time  before  the  lamb's  birth  will  show 
distinct  traces  of  arsenic.  Thorpe  gives  the  following  figures  for  the 
amounts  of  arsenic  in  woolen  materials: 

Arsenious  Oxide 

Mgms.  per  Gram  of 

Material. 

Flannel  from  natural  wool 0.005-0.009 

White  Berlin  wool 0.037 

Cream  flannel 0.004 

Welsh  flannel 0.015 

Vest  wool  (undyed) 0.011 

Linen  (white) Free 

Silk  (midyed) 0.001 

Wool  from  lamb  (mother  treated  with  arsenical 

dip) 0.0005 

Wool  from  lamb  (mother  dipped  shortly  before 

birth  of  the  lamb) 0.019 

Wool  from  ewe   (treated  with  carbolic  dip   15 

months  previously) 0 .  047 

5.  Coloring  Matter. — Sheep's  wool  is  nearly  always  white  in  color, 
though  sometimes  it  may  occur  in  the  natural  colors  of  gray,  brown,  or 
black. 

There  do  not  appear  to  be  any  laws  regulating  the  occurrence  of  black 
wool  in  sheep.  Beyond  the  difference  in  color  there  is  not  any  noticeable 
difference  in  structure  or  properties  between  black  wool  and  ordinary  wool. 
Climatic  conditions  do  not  seem  to  have  any  influence  on  the  production  of 
black  wool,  and  it  is  as  liable  to  occur  in  one  breed  as  in  another.  It  would 
be  thought  the  question  of  heredity  would  have  an  important  bearing  on  the 
origin  of  black  wool;  but  even  this  factor  appears  to  be  without  influence, 
as  a  black  lamb  may  have  both  parents  white,  both  black,  or  one  white'and 
one  black.  The  amount  of  black  wool  appearing  in  the  American  domestic 
trade  is  about  3  to  5  percent  of  the  total  clip.  It  is  used  almost  exclu- 
sively in  the  undyed  condition  for  the  production  of  gray  mixes  for  hosiery 
and  underwear. 

The  coloring  matter  in  wool  appears  to  withstand  the  action  of  alkalies 
and  acids,  though  it  is  not  especially  permanent  toward  light.  It  appears 
to  be  distributed  in  the  fiber  in  quite  a  different  manner  from  that  of  the 
artificially  applied  dyes.  The  natural  coloring  matter  appears  to  be 
contained  particularly  in  the  cells  of  the  cortical  layer  and  the  marrow  in  a 
granular  form,  and  to  occur  to  a  greater  extent  in  the  medullary  than  in 
the  cortical  cells.  In  fibers  which  are  only  slightlj''  colored  the  walls  of 
the  cells  are  almost  colorless;  though  when  the  fiber  becomes  very  strongly 


126 


CHEMICAL  NATURE  AND  PROPERTIES  OF  WOOL 


colored  the  cell-walls  also  appear  to  be  impregnated  with  the  coloring 
matter.  In  wools  which  have  been  dyed,  however,  the  cell-walls  are 
nearly  always  uniformly  colored,  in  consequence  of  which  the  medulla  of 
the  fiber  becomes  less  pronounced;  whereas,  with  naturally  colored  wools, 
the  medulla  is  usually  rendered  more  distinct  through  the  deposit  of 
coloring  matter. 

6.  Chemical  Constitution  of  Wool ;  Keratine. — The  wool  fiber  has  been 
found  to  consist  of  five  chemical  elements — namely,  carbon,  hydrogen, 
oxygen,  nitrogen,  and  sulfur.  Nitrogen  is  an  ingredient  common  to  both 
wool  and  silk,  but  sulfur  is  distinctly  characteristic  of  wool  and  hair  fibers. 
In  its  chemical  nature  wool  is  classed  as  a  proteid,  known  as  keratine. 
As  its  constituents  are  not  rigidly  constant  in  their  proportions,  we  cannot 
assign  to  wool  a  definite  chemical  formula. 

On  an  average,  its  composition  may  be  taken  as  follows: 

Percent. 

Carbon 50 

Hydrogen 7 

Oxygen 26-22 

Nitrogen 15-17 

Sulfur 2-  4 

Keratine,  free  from  ash,  water,  and  melanine,  on  hydrolysis,  gave  the 
following  amounts  of  monamino-acids  :^ 


Keratine  from 

Horsehair, 

Percent. 

Keratine  from 

Goose-feathers, 

Percent. 

Glycine 

Alanine 

Amino- valeric  acid 

4.7 
1.5 
0.9 
7.1 
3.4 
0.3 
3.7 
3.2 
0.6 

2.6 
1.8 
0.5 

Leucine .  .          

8.0 

Pyrolidine-2-carboxylic  acid 

Aspartic  acid 

3.5 
1.1 

Glutaminic  acid 

2.3 

TjTosine 

3.6 

Serine  . .            .    .                    

0.4 

According  to  the  tables  of  Cohnheim,  the  percentages  of  known  con- 
stituents in  the  keratine  from  hair  are  as  follows: 

Percent. 

Leucine 14 

Glutaminic  acid 12 

Aspartic  acid Not  determined 

Cystine 13.92 

Tyrosine 3 

Ammonia Large  amount 

1  Abderhalden,  Zdt.  physiol.  Chem.,  vol.  46,  p.  31. 


CHEMICAL  CONSTITUTION   OF  WOOL;    KERATINE 


127 


Bowman  gives  the  following  analyses  of  four  different  grades  of  English 
wool : 


Constituent. 


Lincoln 
Wool. 


Irish 
Wool. 


Northumber- 
land Wool. 


Southdown 
Wool. 


Carbon . . . 
Hydrogen 
Nitrogen . 
Oxygen. . 
Sulfur.... 
Loss 


52.0 

6.9 

18.1 

20.3 

2.5 

0.2 


49.8 

7.2 

19.1 

19.9 

3.0 

1.0 


50.8 

7.2 

18.5 

21.2 

2.3 


51.3 
6.9 

17.8 

20.2 

3.8 


These  analyses  were  made  of  wool  which  had  been  purified  by  extraction 
with  water,  alcohol,  and  ether. 

Abderhalden  and  Voitinovici  ^  give  the  following  animo  bodies  obtained 
from  decomposition  products  of  wool : 

Percent. 

Glutaminic  acid 12.9 

Leucine 11.5 

Cystine 7.3 

Alanine 4.4 

Proline 4.4 

Tyrosine 2.9 

Valine 2.8 

Aspartic  acid 2.3 

GlycocoU 0.58 

Serine 0.1 

The  wool  fiber  as  a  whole  does  not  appear  to  be  a  homogeneous  chemical 
compound;  instead  of  being  a  simple  molecular  bod}^  to  which  a  definite 
formula  might  be  given,  it  is  doubtless  composed  of  several  chemically 
distinct  substances.  This  is  evidenced  by  the  fact  that  the  proximate 
constituents  of  wool  are  by  no  means  constant  in  their  amount;  further- 
more, certain  of  its  constituents  are  in  part  removed  by  simply  boiling  the 
fiber  in  water  without  a  structural  disorganisation  taking  place.  The 
sulfur  content  is  especially  liable  to  fluctuation,  and  is  the  most  readily 
removed  of  the  chemical  elements  of  which  the  fiber  is  composed ;  in  fact, 
so  easily  is  some  of  the  sulfur  removed  as  such  by  various  solvents,  that  it 
would  seem  to  indicate  that  this  constituent  existed  in  wool  either  in 
the  free  condition  or  in  a  compound  of  exceedingly  unstable  character. 

Schuetzenberger,  by  decomposing  pure  wool  fiber  by  heating  with  a 
solution  of  barium  hydrate  at  170°  C,  obtained  the  following  decomposi- 
tion products: 

1  Chem.  Cenlral-Blatl,  1907,  p.  707. 


128  CHEMICAL  NATURE  AND  PROPERTIES  OF  WOOL 

Percent. 

Nitrogen  (evolved  as  ammonia) 5 .  25 

Carbonic  acid  (separated  as  barium  carbonate) 4 .  27 

Oxalic  acid  (separated  as  barium  oxalate) 5 .  72 

Acetic  acid  (by  distillation  and  titration) 3 .  20 

Pyrol  and  volatile  products 1  to  1 .  50 

f C   47,85 
Proximate  composition  of  fixed  residue,  containing 
leucine,  tyrosine  and  other  volatile  products 


H  7.69 
N  12.63 
O  31.18 


Williams  has  shown  that  by  distilling  wool  with  strong  caustic  potash 
a  large  amount  of  ammonia  was  obtained  in  the  distillate,  together  with 
butylamine  and  amylamine.  Dry  distillation  of  wool  yields  an  oil  of  a 
very  disagreeable  odor,  probably  consisting  of  various  sulfuretted  bases; 
also  a  considerable  amount  of  pyrol  and  hydrogen  sulfide  gas,  together 
with  a  small  amount  of  carbon  disulfide,  and  traces  of  various  oily  bases. 

7.  Nitrogen  in  Wool. — The  presence  of  nitrogen  in  wool  is  readily 
made  evident  by  simply  burning  a  small  sample  of  the  fiber,  when  the 
characteristic  empyreumatic  odor  of  nitrogenous  animal  matter  will  be 
observed.  By  heating  wool  in  a  small  combustion  test-tube  it  will  be 
noticed  that  ammonia  is  among  the  gaseous  products  evolved,  and  can  be 
tested  for  in  the  usual  manner. 

Schuetzenberger  has  shown  that  the  products  of  the  hydrolysis  of 
wool  by  baryta-water  are  analogous  to  those  of  albuminoids  containing 
amino  groups;  the  experiments  of  Prud'homme  ^  and  Flick  also  indicate 
the  presence  of  imino  rather  than  amino  groups  in  wool.  The  fact  that 
wool  absorbs  nitrous  acid,  and  combines  with  phenols,  which  is  supposed 
to  indicate  the  presence  of  amino  groups,  may  be  explained  by  the  forma- 
tion of  nitrosamines  with  the  imino  groups,  which  would  also  yield  colored 
derivatives  with  phenols.  Saget  ^  supports  the  theory  that  wool  contains 
amino,  imino,  and  carboxyl  groups,  claiming  that  this  constitution  is 
required  to  explain  why  wool  mordanted  with  tannate  of  tin  loses  its 
affinity  for  acid  dyes. 

8.  Lanuginic  Acid. — The  amino  acid  of  keratine  has  received  the  name 
of  lanuginic  acid,  and  has  been  prepared  by  dissolving  purified  wool  in  a 
strong  solution  of  barium  hydrate,  precipitating  the  barium  by  means  of 
carbon  dioxide,  and  after  filtering,  treating  the  liquid  with  lead  acetate, 
whereby  the  lead  salt  is  obtained.  This  is  decomposed  by  means  of 
hydrogen  sulfide,  and  the  lanuginic  acid  obtained,  after  evaporation, 
as  a  dirty-yellow  substance.  Its  solution  in  water  yields  colored  lakes  with 
the  acid  and  basic  dyestuffs,  and  also  with  the  various  mordants.  Cham- 
pion^ gives  the  formula  of  lanuginic  acid  as  C19H30N5O10,  but  Knecht 

1  Rev.  Gen.  Mat.  Col,  1898,  p.  209. 

2  Monit.  Scient.,  1910,  p.  80. 

3  Compt.  rend.,  vol.  72,  p.  330. 


BROWNING  OF  WOOL  129 

and  Appelyard^  reject  this  formula,  as   they  show  that   the  compound 
contains  about  3  percent  of  sulfur. 

According  to  Knecht,  lanuginic  acid  possesses  the  following  properties : 
It  is  soluble  in  water,  sparingly  so  in  alcohol,  and  insoluble  in  ether.  Its 
aqueous  solution  yields  highly  colored  precipitates  with  the  acid  and  basic 
dyestuffs;  tannic  acid  and  bichromate  of  potash  also  give  precipitates. 
The  following  mordants  in  the  presence  of  sodium  acetate  also  give  precipi- 
tates :  Alum,  stannous  chloride,  copper  sulfate,  ferric  chloride,  ferrous 
sulfate,  chrome  alum,  silver  nitrate,  and  platinum  chloride.  Lanuginic 
acid  exhibits  all  the  properties  of  a  proteoid,  and  may  therefore  be  classed 
among  the  albuminoids;  it  is  soluble  in  water  at  all  temperatures,  and  its 
solution  is  not  coagulated.  With  Millon's  reagent  and  with  the  double 
compound  of  phosphoric  and  tungstic  acids,  it  shows  the  characteristic 
albuminoid  reactions.  Knecht  recommends  the  use  of  a  solution  of  wool 
in  barium  hydrate  for  the  purpose  of  animalising  vegetable  fibers.  Cotton 
so  treated  is  capable  of  being  dyed  with  acid  and  basic  dyestuffs. 

When  heated  to  100°  C,  lanuginic  acid  becomes  soft  and  plastic,  and 
the  majority  of  its  colored  lakes  also  melt  at  this  temperature.  Knecht 
gives  the  following  analysis  of  lanuginic  acid : 

Percent. 

Carbon 41 .61 

Hydrogen 7.31 

Nitrogen 10.26 

Sulfur 3.35 

Oxygen 31 .  44 

93.97 

Though  lanuginic  acid  contains  a  notable  amount  of  sulfur  in  its  composi- 
tion, it  is  not  blackened  by  treatment  with  sodium  plumbite. 

9.  Browning  of  Wool. — Fort  ^  has  studied  the  development  of  a  brown 
color  on  wool  through  exposure  and  other  agencies,  and  has  come  to  the 
conclusion  that  the  browning  of  wool  by  exposure  is  largely  due  to  the 
degradation  of  the  free  amino  compounds  which  may  be  present  at  the 
start  and  which  may  also  be  developed  in  the  wool  by  exposure.  Wool 
which  has  been  exposed  shows  a  greater  tendency  to  go  brown  when 
afterwards  heated,  steamed,  boiled,  or  treated  with  alkalies,  as  these  treat- 
ments all  develop  free  amino  groups  in  wool.  The  similar  development 
of  an  increased  affinity  for  acid  dyes  after  wool  has  undergone  exposure 
or  any  of  these  treatments,  and  the  increased  reaction  with  naphthoquinone 
sulfonate  supports  the  befief  that  a  development  of  amino  groups  takes 
place.  The  brown  color  produced  by  these  agencies  may  be  considerably 
removed  by  acid  treatment  or  stoving,  while  a  preliminary  treatment  of 

1  Jour.  Soc.  Dyers  &  Col,  1889,  p.  71. 
*  Jour.  Soc.  Dyers  &  Col,  1916,  p.  184. 


130      CHEMICAL  NATURE  AND  PROPERTIES  OF  WOOL 

the  wool  with  sulfuric  acid  renders  it  less  liable  to  go  brown  under  any 
of  these  treatments.  The  properties  of  "  faded  "  wool  as  distinguished 
from  fresh  wool  are  seen  in  the  dyeing  of  worn  garments,  where  often  the 
reaction  of  the  wool  with  the  dyestuff  is  not  at  all  the  same  as  it  would 
be  with  fresh  wool.  Also  if  wool  fabrics  are  partly  exposed  and  partly 
protected  for  a  considerable  period  of  time  and  then  dyed,  streaks  will 
develop.  Fade  marks  are  also  liable  to  develop  on  wool  fabrics  which 
have  been  boiled  or  steamed  for  the  production  of  luster  and  spot-proof 
finishes. 

10.  Sulfur  in  Wool. — The  presence  of  sulfur  in  wool  can  be  shown  by 
dissolving  a  sample  of  the  fiber  in  a  solution  of  sodium  plumbite  (obtained 
by  dissolving  lead  oxide  in  sodium  hydrate),  when  a  brown  coloration  will 
be  observed,  due  to  the  formation  of  lead  sulfide.  On  adding  hydrochloric 
acid  to  the  solution  and  heating,  the  odor  of  sulfuretted  hydrogen  will  be 
distinctly  noticed.  The  application  of  this  test  to  show  the  presence  of 
sulfur  in  wool  is  sufficient  to  discriminate  chemically  between  that  fiber 
and  those  consisting  of  silk  or  cotton,  and  also  to  detect  wool  in  admixture 
with  other  fibers. 

The  older  methods  of  hair-dyeing  were  based  on  this  same  reaction, 
solutions  of  soluble  lead  salts,  such  as  sugar  of  lead,  l)eing  applied  to  the 
hair,  with  the  result  that  lead  sulfide  would  be  formed  and  cause  a  dark- 
brown  coloration.  The  use  of  such  preparations,  however,  is  dangerous, 
as  they  are  liable  to  cause  lead-poisoning. 

The  presence  of  sulfur  in  wool  may  at  times  be  the  cause  of  certain 
defects  in  the  dyeing  process.  In  neutral  or  alkaline  baths,  if  lead  is 
present,  the  color  obtained  on  the  fiber  will  be  more  or  less  affected  by  the 
lead  sulfide  formed  on  the  wool,  and  serious  stains  may  be  the  result. 
The  presence  of  sulfuric  acid,  however,  prevents  this,  and  no  staining  of  the 
fiber  takes  place.  Stains  are  sometimes  produced  when  wool  is  mordanted 
with  stannous  chloride,  as  in  the  dyeing  of  cochineal  scarlets,  due  to  the 
formation  of  stannous  sulfide.  Occasionally  woolen  printed  goods  exhibit 
brownish  stains  on  the  white  or  light-colored  portions  after  being  steamed. 
These  may  be  due  to  slight  traces  of  copper  or  lead  which  have  been 
deposited  on  the  cloth  during  its  manipulation  and  passage  through  the 
machines,  these  metals,  when  the  wool  is  steamed,  forming  dark-colored 
sulfides  which  cause  the  stains.  By  locally  applying  a  weak  solution  of 
hydrogen  peroxide  such  discolorations  may  be  removed  without  injury 
to  the  prin  ed  color. 

Chevreul  recognised  the  fact  that  in  certain  dyeing  operations  it  was 
necessary  to  remove  the  sulfur  from  wool  as  far  as  possible  in  order  to 
obtain  the  best  results.  He  accomplished  this  by  steeping  the  wool  in 
milk  of  lime  and  afterward  in  a  weak  bath  of  hydrochloric  acid,  and 
finally  washiner- 


SULFUR  IN  WOOL  131 

The  amount  of  sulfur  existing  in  wool  does  not  appear  to  be  a  very- 
constant  factor,  but  varies  in  different  samples  of  wool  from  0.8  to  4  per- 
cent. Wool  is  similar  to  other  albuminoids  in  that  it  contains  a  relatively 
small  though  a  widely  fluctuating  amount  of  sulfur.  The  following  sulfur 
compounds  have  been  isolated  from  the  decomposition  products  of  the 
albuminoids:  Cystine,  cysteine,  thiolactic  acid,  thioglycollic  acid,  ethyl 
sulfide,  ethyl  mercaptan,  sulfuretted  hydrogen,  and  diethyl-thetine. 
The  manner  in  which  the  sulfur  exists  in  the  molecular  structure  of  the 
fiber  is  by  no  means  clear,  as  the  majority  of  it  is  readily  removed  without 
any  apparent  structural  modification  of  the  fiber  itself.  According  to 
Chevreul  the  amount  of  sulfur  in  wool  was  reduced  to  0.46  percent  by 
several  treatments  with  lime-water.  Treatment  with  a  concentrated 
solution  of  caustic  soda  in  such  a  manner  as  not  to  disintegrate  the  fiber 
will  remove  as  much  as  84.5  percent  of  the  sulfur  originally  present  in 
the  wool.  On  a  sample  of  wool  containing  3.42  percent  of  sulfur,  treat- 
ment in  this  manner  left  only  0.53  percent  of  sulfur  in  the  fiber.  This 
would  appear  to  indicate  that  the  sulfur  is  not  a  structural  constituent 
of  the  wool  fiber.  The  presence  of  sulfuric  or  sulfurous  acids  has  formerly 
never  been  observed  in  the  decomposition  products  of  albuminoids  and 
this  led  to  the  opinion  that  the  albumin  molecule  did  not  contain  sulfur 
in  combination  with  oxygen.  Raikow,^  however,  finds  that  when  purified 
unbleached  wool  is  treated  with  phosphoric  acid  considerable  quantities 
of  sulfurous  acid  are  evolved.  The  fact,  however,  that  the  sulfur  present 
is  not  all  removed  by  even  such  severe  treatment  as  described  would  also 
serve  to  indicate  that  this  element  may  exist  in  wool  in  two  forms,  the  one 
an  ultimate  constituent  of  the  fiber,  and  the  other,  and  major  part,  as  a 
more  loosely  combined  compound.  The  fact  that  the  amount  of  sulfur 
naturally  present  in  wool  is  by  no  means  constant  would  also  tend  to  sup- 
port this  view;  as  would  also  the  fact  that  the  major  portion  of  the  sulfur 
is  so  readily  split  off  to  form  metallic  sulfides.  On  dissolving  wool  in 
boiling  caustic  soda,  it  does  not  appear  that  all  of  the  sulfur  is  converted 
into  sodium  sulfide,  as  only  about  80  percent  of  it  can  be  obtained  as 
hydrogen  sulfide  when  the  caustic  soda  solution  is  treated  with  acid. 
Probably  the  remainder  of  the  sulfur  exists  in  the  wool  as  a  sulfonic  acid, 
or  some  compound  of  a  similar  nature. 

According  to  Prud'homme  ^  the  sulfur  in  the  wool  is  probably  combined 
either  as 

S 


\  I  I 

NC„H2„C0         or  NC„H2„CS. 

1  Chem.  Zeit.,  1905,  p.  900. 

2  Rev.  Gen.  Mat.  Col.,  1898,  p.  209. 


132      CHEMICAL  NATURE  AND  PROPERTIES  OF  WOOL 

It  is  also  contained  in  the  natural  coloring  matter  of  the  wool. 

White  gives  the  following  method  for  the  determination  of  sulfur 
in  wool:  Digest  1  gram  of  wool  with  caustic  soda  solution  and  lead  acetate, 
acidify  with  acetic  acid  and  further  digest,  filter  and  was  the  precipitated 
lead  sulfide.  Decompose  the  latter  together  with  the  filter  paper  with 
hydrochloric  acid  (cone),  make  alkaline  with  caustic  soda,  and  then 
acidify  with  acetic  acid  and  filter.  Determine  the  lead  in  the  filtrate  as 
chromate  in  the  usual  manner.  The  method  is  said  to  give  concordant 
and  accurate  results. 

11.  Hygroscopic  Quality. — Wool  is  more  hygroscopic  than  any  other 
fiber,  but  the  amount  of  moisture  it  will  contain  will  vary  considerably 
according  to  the  humidity  and  temperature  of  the  surrounding  atmosphere. 
Under  average  conditions,  however,  it  will  contain  from  12  to  14  percent 
of  absorbed  moisture.  The  hygroscopic  quality  of  wool  is  a  subject  of 
considerable  importance  in  the  commercial  handling  of  this  fiber,  for  the 
weight  of  any  given  lot  of  wool  will  vary  within  large  limits  in  accordance 
with  climatic  conditions;  that  is  to  say,  the  shipment  of  wool  from  one 
locality  to  another  of  different  humidity  and  temperature  will  cause  a 
loss  or  gain  in  the  apparent  weight  of  the  material.^     So  important  a 

1  In  this  connection  the  Wyoming  Experiment  Station  has  made  some  interesting 
studies  (Bulletin  132),  the  results  of  the  experiments  being  summarised  as  follows: 

Small  samples  of  wool  transferred  in  the  summer  from  Laramie,  Wyoming,  to  the 
suburbs  of  Washington,  D.  C,  had  increased  4  or  5  percent  in  moisture  content  shortly 
after  arriving  at  their  destination.  Fifty-gram  samples  exposed  to  the  outdoor  air 
at  Laramie,  Wyoming,  in  August  underwent  wide  variations  in  moisture  content  in 
response  to  the  fluctuations  in  the  temperature  and  relative  humidity  of  the  air, 
changes  of  moisture  content  as  high  as  6  percent  having  taken  place  in  less  than 
twenty-four  hours.  It  was  found  that  as  compared  to  the  pure  wool  fiber  exposed 
to  the  same  conditions,  unwashed  wool  that  was  comparatively  free  from  insoluble 
earthy  matter,  absorbed  more  moisture  and  was  more  affected  by  changes  in  the 
moisture  of  the  air.  It  was  also  found  that  on  the  same  basis  of  comparison,  wool 
containing  a  high  percentage  of  sand  absorbed  less  moisture  and  was  less  affected  by 
changes  in  the  air.  A  detailed  analysis  of  the  hygroscopic  properties  of  the  pure 
fiber  and  natural  impurities  of  a  sample  of  Leicester  wool  showed  that  if  the  percentage 
of  moisture  in  the  sample  was  called  1,  then  the  suint  was  2  to  2|,  the  wool-fat  f  to  Ij 
and  the  insoluble  dirt  which,  in  this  case,  consisted  of  a  small  amount  of  clay  and 
finely  powdered  vegetable  matter,  was  1.  Drying  once  to  a  constant  weight  did  not 
measurably  affect  the  power  to  re-absorb  the  normal  amount  of  moisture.  A  sample 
of  wool  that  has  been  exposed  to  an  atmosphere  with  a  high  relative  humidity  upon 
being  brought  into  one  of  lower  relative  humidity  comes  into  eq\iilibrium  with  the 
latter  by  losing  weight  at  a  rate  directly  in  proportion  to  the  area  of  surface  exposed, 
and  the  rate  of  change  to  a  given  area  of  surface  is  a  direct  function  of  the  difference 
between  the  regain  of  the  wool  and  its  normal  regain  for  the  air  surrounding  it.  A 
few  conclusions  with  a  practical  application  may  be  drawn  from  this  summary  and 
the  work  preceding  it.  The  first  one  has  long  been  known  to  practical  wool  men, 
namely,  that  wool  from  the  Mountain  States  gains  in  weight  upon  being  stored  in 
warehouses  along  the  Atlantic  seaboard.     A  second  one  is  that  the  greater  the  pro- 


WATER  OF  HYDRATION   IN   WOOL  133 

factor  ha^i  this  become  in  the  commercial  relations  between  wool-dealers, 
that  conditioning  houses  for  wool  have  been  established  in  many  European 
centers  for  the  purpose  of  carefully  ascertaining  the  actual  amount  of 
fiber  and  moisture  present  in  any  given  lot  of  wool,  the  true  weight  being 
based  on  a  certain  standard  percentage  of  moisture,  or  so-called  "  regain." 
This  percentage  varies  somewhat  with  the  character  of  the  material  and 
also  the  conditioning  house,  ranging  from  16  to  19  percent.  The  hygro- 
scopic quality  of  wool  also  has  an  important  bearing  on  the  spinning 
and  finishing  processes  for  this  fiber,  it  being  necessary  to  maintain  a 
definite  and  uniform  condition  of  moisture  in  order  that  the  best  results 
be  obtained  in  the  spinning  of  yarns  and  the  finishing  of  the  woven 
fabric. 

Wright  ^  as  the  result  of  an  investigation  of  the  absorption  of  moisture 
by  wool  arrives  at  the  conclusion  that  the  amount  of  moisture  which  a 
wool  can  absorb  from  the  atmosphere  depends  on  several  factors,  as 
follows:  (1)  The  relative  humidity  of  the  atmosphere.  (2)  Pure  wool 
fiber,  of  which  greasy  wool  contains  about  50  percent,  can  absorb  from 
18  to  20  percent  of  its  weight  of  moisture  from  the  atmosphere,  but  this 
amount  is  not  sufficient  to  account  for  all  the  moisture  absorbed  by  the 
dry  normal  wool  fiber.  (3)  Natural  wool-fat,  present  in  greasy  wool  to 
the  extent  of  about  17  percent,  is  capable  of  absorbing  about  17  percent 
of  its  weight  of  atmospheric  moisture.  (4)  Suint,  or  wool  perspiration, 
is  pjesent  in  greasy  wools  to  the  extent  of  about  13  percent,  and  is  very 
hygroscopic,  absorbing  60-67  percent  of  moisture. 

12.  Water  of  Hydration  in  Wool. — The  wool  fiber  also  appears  to  pos- 
sess a  certain  amount  of  water  of  hydration,  which  is  no  doubt  chemically 
combined  in  some  manner  with  the  fiber  itself;  for  it  has  been  observed 
that  wool  heated  to  above  100°  C.  becomes  chemically  altered  through 
a  loss  of  water  at  that  temperature.  This  will  no  doubt  explain  the  fact 
that  air-dried  wool  is  superior  in  quality  to  that  dried  by  means  of  artificial 
heat,  which  usually  signifies  a  rather  elevated  temperature.  According 
to  Persoz,  the  destructive  action  of  high  temperatures  on  the  wool  fiber 
may  be  prevented  by  saturating  the  material  with  a  10  percent  solution 

portion  of  sand  in  the  wool,  the  less  this  gain  in  weight  caused  by  storage  at  the  sea- 
board, will  be.  A  third  is  that,  other  things  being  equal,  the  more  suint  there  is  in 
wool,  the  greater  will  be  the  increase  in  weight  when  stored  in  the  East.  A  fourth 
is  that  in  the  Mountain  States,  in  the  summer  when  the  days  are  hot  and  dry  and  the 
nights  cool,  wool  spread  out  in  thin  layers  exposed  to  the  air  may  weigh  several  pounds 
more  to  the  bundled  in  the  early  morning  than  in  the  mid-afternoon.  A  fifth  is  that 
sacked  or  baled  wool,  especially  when  stored  in  large  piles  in  closed  warehouses, 
changes  its  moisture  content  very  slowly,  and  if  it  is  desired  to  hasten  this  process, 
the  wool  should  be  spread  out  and  the  packages  opened  and  handled  in  a  place  where 
there  is  a  free  circulation  of  air. 

^Jour.  Soc.  Chem.  Ind.,  1909,  p.  1020. 


134 


CHEMICAL  NATURE  AND  PROPERTIES  OF  WOOL 


of  glycerol,  after  which  treatment  the  wool  may  be  exposed  to  a  tempera- 
ture of  140°  C.  without  being  affected.  The  explanation  of  this  action 
is  no  doubt  to  be  found  in  the  fact  that  glycerol  holds  water  with  con- 
siderable energy,  and  even  at  these  elevated  temperatures  all  of  the 
moisture  originally  present  in  the  wool  is  not  driven  out  of  the  fiber.  In 
order  to  economise  time,  it  is  sometimes  necessary  to  dry  wool  rather 
quickly  by  the  use  of  suitable  machinery  and  high  temperatures.  Where 
a  proper  regulation  of  the  temperature  is  possible,  the  wet  wool  may  be 
subjected  to  quite  a  high  degree  of  heat  without  injury,  for  the  fiber  itself 
does  not  become  heated  up,  due  to  the  rapid  evaporation  of  the  moisture. 
As  the  fiber  becomes  drier,  however,  it  is  important  that  the  temperature 
fall,  so  that  at  the  end  of  the  operation,  when  the  wool  has  become  dried 
to  its  normal  content  of  moisture,  the  temperature  should  be  that  of  the 
atmosphere. 

13.  Effect  of  Moisture  on  Properties  of  Wool. — Too  much  importance 
cannot  be  attached  to  the  proper  drying  of  wool  in  all  of  its  stages  of 
manufacture,  either  in  scouring,  dyeing,  washing,  or  finishing.  If  wool 
is  overdried;  that  is,  if  the  moisture  in  it  is  reduced  to  an  amount  much  less 
than  that  which  it  would  normally  contain,  inferior  goods  will  always 
be  the  result,  for  the  intrinsic  good  qualities  of  the  fiber  become  greatly 
depreciated  every  time  such  a  mistake  is  committed. 

Notwithstanding  the  rather  popular  idea  that  the  strength  of  woolen 
goods  increases  with  hygroscopic  moisture,  the  very  opposite  is  the  case. 
Barker  states  ^  that  the  drier  the  wool  the  stronger  it  is.  Woodmansey  ^ 
shows  that  when  moisture  is  driven  off  the  strength  of  woolen  fabrics  is 
considerably  increased,  but  the  increase  disappears  on  exposure  to  the 
air.  The  effect  of  very  prolonged  drying  is  usually  to  give  an  increase  of 
strength  to  the  wool  w^hich  lasts  at  least  several  days.  Woodmansey 
tested  pieces  dried  at  100°  C.  and  cooled  in  a  desiccator,  and  then  exposed 
to  the  air,  as  follows: 


Direct  from  desiccator 

After  5  minutes 

After  15  minutes 

After  30  minutes 

After  60  minutes 


Average  Strength 

of  5  (3")  Warp 

Strips  in  Poimds, 


188.4 
185.8 
172  4 
161.0 
158.4 


Average  Elonga- 
tion before 
Rupture,  Inches. 


1.225 
1.525 
1.800 
1.875 
2.150 


Moisture 
Content, 
Percent. 


Dry 
3.0 
5.5 
7.5 

8.7 


1  Jmr.  Soc.  Dyers  &  Col,  1905,  p.  36. 

2  Jour.  Soc.  Dyers  &  Col,  1918,  p.  227. 


EFFECT  OF   MOISTURE  ON   PROPERTIES  OF   WOOL 


135 


A  continuation  of  these  figures  was  made  possible  by  wetting  the 
cloth  and  then  allowing  it  to  dry  in  the  air. 


Average  Strength 

of  5  (3")  Warp 
Strips  in  Pounds. 


Average  Elonga- 
tion before 
Rupture,  Inches. 


Moisture 
Content, 
Percent. 


Before  treatment 
After  wetting .  .  . 

Damp 

Air-drv 


160.0 
130.7 
123.6 
156.3 


2.26 
4.53 
4.46 
2.67 


10.04 
53.0 
33.0 
10.54 


The  following  table  shows  the  percentage  of  moisture  in  air-dried  wool 
and  when  exposed  to  an  atmosphere  saturated  with  moisture,^  as  com- 
pared with  the  same  values  for  other  fibers : 


Fiber. 

Air-dry. 

Saturated. 

Fiber. 

Air-dry. 

Saturated. 

Wool 

8-14 

10-12 

6-8 

6-8 

30 
30 
21 

18 

Manila  hemp .... 

Jute 

Flax 

8-12 
6 

5-8 

40 

Silk 

Cotton 

Ramie 

23 
13 

The  influence  of  moisture  in  yarns  on  their  weaving  qualities  "  is  an 
interesting  factor.  Excess  of  moisture  over  the  normal  amount  appears 
to  decrease  somewhat  the  tensile  strength  of  worsted  yarns,  while  it 
increases  considerably  the  elasticity.  With  cotton,  the  result  is  different; 
the  elasticity  alters  but  very  slightly  and  the  strength  increases  a  little. 
Silk  appears  to  follow  the  same  variations  as  wool. 

Variation  in  the  moisture  in  yarns  due  to  variations  in  the  relative 
atmospheric  humidity  also  has  a  very  appreciable  influence  on  the  tensile 
strength  and  count  (or  size)  of  such  yarns.  W.  S.  Lewis  {National  Bureau 
of  Standards)  has  made  a  detailed  study  of  these  effects,  and  points  out 
their  influence  on  the  testing  of  worsted  yarns.  The  results  show  that 
with   common   changes  in  atmospheric  conditions,   worsted  yarns  may 

1  Kimura  (Chem.  Zentralbl.,  1922,  p.  1023)  has  found  that  in  an  atmosphere  satu- 
rated with  moisture  wool  absorbs  28 . 2  to  28 . 7  percent  of  moisture,  cotton  19 . 8  to  20 . 0 
percent,  linen  20.2  to  20.5  percent,  pine  wood  22  to  24  percent  and  paper  15.6  to  24.9 
percent.  When  exposed  to  the  action  of  gaseous  ammonia  wood  retains  50  percent, 
paper  and  wool  4  percent,  and  cotton  and  linen  0.4  percent. 

2  Barker,  Jour.  Soc.  Dyers  &  Col,  1905,  p.  36. 


136 


CHEMICAL  NATURE  AND  PROPERTIES  OF  WOOL 


increase  or  decrease  as  much  as  18  to  22  percent  in  tensile  strength,  1^  to  3 
in  yarn  count  and  from  250  to  1700  yds.  per  pound.  In  view  of  these 
marked  variations  in  the  count,  yardage  and  tensile  strength  of  worsted 
yarns  due  to  the  influence  of  moisture,  it  is  advisable  to  adopt  some 
standard  conditions  of  temperature  and  relative  humidity  in  the  physical 
testing  of  textile  materials,  in  order  that  different  tests  may  be  of  a  strictly 
comparable  nature.  The  atmospheric  conditions  recommended  are  65 
percent  relative  humidity  at  a  temperature  of  70°  F. 

The  following  table  shows  the  influence  of  different  relative  humidities 
on  the  tensile  strength  of  worsted  yarns,  being  a  mean  of  a  large  number  of 
tests  of  different  sizes  of  yarns : 

Percent  Relative  Tensile  Strength 

Humidity  at  70°  F.  in  Grams. 

45 234 

55 231 

65 220 

75 216 

85 191 

The  following  tables  show  the  influence  of  humidity  on  the  count  and 
yardage  of  worsted  yarns : 


Samples. 


Singles. 


1 

2 

20.25 

24.58 

19.77 

23.97 

18.82 

22.79 

0.48 

0.61 

0.95 

1.18 

1.43 

1.79 

269 

342 

532 

661 

801 

1002 

6 


Two-ply. 


Yarn  count  at  45%  rel.  hum. . 

"      "65%  rel.  hum.. 

"     "85%  rel.  hum.. 

Diff.  in  count  45%  and  65% . 

"     "     "     65%and85%. 

"  "  "  45%and85%. 
Diff.  yards  per  pound: 

45%  and  65% 

65%  and  85% 

45%  and  85% 


25.51 

24.94 

23.80 

0.57 

1.14 

1.71 

319 
638 
958 


34.49 

33.68 

31.77 

0.81 

1.91 

2.72 

454 
1070 
1523 


35.47 

34.71 

32.85 

0.76 

1.86 

2.62 

426 
1042 
1467 


39.09 

38.08 

36.03 

1.01 

2.05 

3.06 

566 
1148 
1714 


27.74 

27.18 

25.68 

0.56 

1.50 

2.06 

314 

840 

1154 


34.28 

33.66 

31.80 

0.62 

1.86 

2.48 

347 
1042 
1389 


Scheurer  ^  experimented  with  wool  and  other  fibers  with  respect  to  the 
amount  of  moisture  which  would  be  absorbed  at  100°  C.  in  an  atmosphere 


1  Bull.  Soc.  Ind.  Mulh.,  1900. 


EFFECT  OF  MOISTURE  ON  PROPERTIES  OF  WOOL 


137 


rfVS 

DIAGRAM  Nol. 

1 

-m 

710 

816 

118  M 

Showing  the  averaKe  weights  of  the  same 
Bkein  of  worsted  yam  for  different  times  of  day 
ior  10  observations  a  day,  for  a  period  of  one 
year.      The  unit  of  weight  is  100  grammes  of 
absolutely  dry  yacn. 

The  observations  were  made  in  an  open  shed 
—protected  from  the  wind  and  rain  — but  ex- 
posed to  the  nosmnl  out-door  changes  of  the 
atmosphere- 

& 

• 

N^« 

o 

- 

n7«\>^ 

n6< 

110 

\^16 

116^       1162^        ^A**^" 

^116 

1 1 1 1 

r     1  t  I 

fi        ro      ^        12         1 

1  1  1  1  t  1  1  1  1  1  1  1  1  1  1  r  1  1  1  1  1  1  1  1  1  1 

2              3              4              6              6 

1  1  1  1  1  1  1  1  1  r  1  1  1  1  1  1  r  1  1  1  1  1  1  1  1  1  1  1  1  1 

A.M.                                Noon 

P.M. 

Fig.  73. — Effect  of  Moisture  Content  on  Worsted  Yarn. 


Diagram   No.  2 

-lEO 

T. 

Showing  for  the  same  times  of  day,  the  aver- 

- 

\^                                                   age  weights  of  the  same  skein  of  yam,  the  aver- 

— 

79 

N.                                                age  humidity  and  average  temperature  for  ten 

- 

- 

\                                          observations  a  day   for  a  period  of  nearly  one 

- 

78 

- 

\ 

.77 '                                year. 

- 

\                                          Humidity  observations    not    recorded  for  a 

- 

77 

- 

\                                  short  time,  and  this  period   is   not  included  on 

- 

-119 

v\                              ihis  chart. 

— 

76 

- 

'^\ 

- 

■ 

c>\ 

.^ 

75 

-        118 

)9 

U8» 

^ 

K," 

_ 

74 

£ 

M 

- 

118* 

\ 

264- 

73.| 

'3 

0 

-118 

7P 

rl^8                                  62'           e2«         ,,, 

§53- 
709  152: 

5i«t:  - 

72  = 
71° 

s^ 

e 

> 

"" 

R^ 

69  < 

y 

°51- 

TOtg 

-117 

492 

679    679 

68^ 
^ 

^ 

49- 

69 
68 

; 

U6«" 

\ 

48- 

67 

- 

47' 

\. 

- 

116W 

"n,,^ 

47- 

66 

, 

y 

46  s 

^v^^ 

. 

1163«      - 

^ 

X 

116  2: 

lies'- 

46- 

66 

L116  457 

w         8 

15            9 

20          10 

30                11 

45             ] 

10          2 

15                  3 

30                  4 

40              5 

^^         45- 

64 

"     V 

,,,,?, 

,  1 1  ,T, 

l1  L]   1   1   1 

,,V,,I, 

n \ 

,,.,?, 

,,,,?,,       ,,1,,, 

,^,,,, 

J 

A.M.                          Noon                            P.M. 

Fig.  74  — Variations  in  Physical  Properties  of  Wool  Due  to  Hygroscopic  Moisture. 


138      CHEMICAL  NATURE  AND  PROPERTIES  OF  WOOL 

saturated  with  steam.     His  results  were  as  follows:   100  grams  each  of  the 
several  fibers  dried  at  100°  C.  fixed  the  following  amounts  of  water: 

Percent. 

Bleached  cotton 23.0 

Unbleached  linen 27 . 7 

Unbleached  jute 28 . 4 

Bleached  silk 36 . 5 

Bleached  and  mordanted  wool 50 . 0 

An  interesting  study  of  the  variations  in  the  content  of  the  hydroscopic 
moisture  in  wool  has  been  made  by  W.  D.  Hartshorne  of  the  Arlington 
Mills.  He  exposed  a  skein  of  worsted  yarn  for  a  year  to  the  varying 
conditions  of  moisture  in  one  place  and  took  regular  weighings  throughout 
stated  times  of  the  day.  The  average  results  are  shown  in  the  accompany- 
ing diagram  (see  Fig.  73).  The  second  diagram  (see  Fig.  74)  shows  the 
curves  representing  the  relative  variations  in  the  weight,  temperature, 
and  humidity,  showing  the  natural  composite  effect  of  these  two  factors 
on  the  amount  of  hygroscopic  moisture  in  the  wool. 


CHAPTER  VI 
ACTION  OF  CHEMICAL  AGENTS  ON  WOOL 

1.  Action  of  Heat. — When  wool  is  heated  for  some  time  in  a  dry  atmos- 
phere to  212°  to  220°  F.  (100°  to  105°  C.)  it  loses  its  total  hygroscopic 
moisture  and  the  fiber  becomes  harsh,  rough,  and  brittle,  and  loses  much 
of  its  tensile  strength.  If  left  in  the  air,  however,  it  rapidly  absorbs 
moisture  again  and  regains  some,  but  not  all,  of  its  former  softness  and 
strength.  Consequently  the  lower  the  temperature  employed  in  the 
drying  of  woolen  goods  the  more  beneficial  it  will  be  in  preserving  the 
original  good  properties  of  the  fiber. 

When  wool  is  heated  in  a  moist  atmosphere  to  212°  F.  (steam  or  boiling 
water)  the  fiber  becomes  quite  plastic,  and  the  form  to  which  it  is  shaped 
under  these  conditions  it  will  retain  if  later  cooled.  This  property  is  the 
basis  of  the  important  finishing  processes  of  wet  and  dry  decatising,  crab- 
bing and  pressing  of  woolen  fabrics,  the  shaping  of  hat  felts,  etc. 

If  maintained  for  any  length  of  time  at  temperatures  much  above 
100°  C.  (especially  if  dry  heat)  the  wool  fiber  will  show  evidence  of  chemical 
decomposition  (by  discoloration  and  great  loss  of  strength).  At  130°  C. 
decomposition  becomes  quite  rapid,  the  wool  acquires  a  yellow  color,  and 
ammonia  is  evolved.  At  140°  to  150°  C.  the  evolution  of  gases  containing 
sulfur  is  also  to  be  noticed. 

When  subjected  to  dry  distillation  wool  evolves  abundant  gases  con- 
taining sulfur,  also  much  ammonium  carbonate  and  pyridine  bases,  leaving 
behind  a  voluminous  residue  of  coke  which  is  very  difficult  to  ignite  to  a 
complete  ash. 

When  heated  in  the  air  in  a  Bunsen  flame  the  wool  fiber  burns  slowly 
and  with  some  difficulty,  developing  a  peculiar  and  rather  unpleasant 
odor  (empyreumatic)  closely  resembling  that  of  burning  feathers  or  horn. 
The  fiber  seems  at  first  to  melt  in  the  flame  so  that  the  burnt  end  exhibits  a 
fused  globular  mass  of  coke. 

2.  Reactions  with  Water  and  Steam. — Though  wool  is  insoluble  in  cold 
water  and  also  in  hot  water  under  ordinary  conditions,  still  the  continued 
action  of  boiling  water  appears  to  decompose  the  wool  fiber  to  a  certain 
extent,  as  both  ammonia  and  hydrogen  sulfide  may  be  detected  in  the 
gases  evolved.  The  soluble  decomposition  products  of  wool  produced 
by  boiling  with  water  show  all  the  characteristic  properties  of  the  peptones. 

139 


140  ACUON  OF  CHEMICAL  AGENTS  ON  WOOL 

Suida  suggests  that  this  action  of  boihng  water  on  wool  may  account  for 
the  lack  of  fastness  to  rubbing  often  noticed  with  basic  colors  on  wool. 

By  heating  wool  to  a  temperature  of  130°  C.  with  water  under  pressure, 
the  fiber  appears  to  become  completely  disorganised,  and  on  drying  may 
be  rubbed  into  a  fine  powder.  At  higher  temperatures  the  fiber  is  com- 
pletely dissolved.  Based  on  this  fact,  Knecht  has  proposed  a  method  for 
the  "  carbonisation  "  of  mixed  woolen  and  silk  goods,  for  the  purpose  of 
recovering  the  silk,  as  the  latter  is  not  materially  affected  by  this  treatment. 
Though  theoretically  possible,  this  method  does  not  appear  to  have  any 
practical  value. 

Gardner  and  Kastner  have  shown  that  on  long  boiling  in  water  a 
small  quantity  of  the  wool  fiber  is  dissolved,  and  to  this  soluble  portion 
they  have  given  the  name  of  wool  gelatine;  it  amounts  to  about  1.65  percent 
of  the  weight  of  the  wool.  Gardner  claims  that  this  substance  plays  an 
important  role  in  the  mordanting  of  wool  with  chrome.  Gelmo  and 
Suida  ^  claim  that  a  partial  hydration  of  the  wool  takes  place  on  prolonged 
boiling  in  water  or  more  particularly  in  dilute  acids. 

Hertz  and  Barraclough  -  point  out  that  wool  on  boiling  in  water  yields 
a  soluble  substance  which  gives  the  tannin  and  biuret  reactions  for  gelatine. 
Solutions  of  lead  acetate,  however,  precipitate  wool  gelatine  from  solution, 
but  have  no  effect  on  solutions  of  ordinary  glue  or  gelatine.  Further 
experiments  seem  to  indicate  that  wool  gelatine  consists  of  three  sub- 
stances: (1)  One  which  is  not  precipitated  by  Night  Blue,  but  which  is 
precipitated  by  the  tannin-salt  reagent  (a  filtered  mixture  of  100  cc.  of  a 
2  percent  solution  of  tannin  and  100  cc.  of  a  saturated  solution  of  salt); 
(2)  one  which  is  precipitated  by  Night  Blue,  and  which  goes  into  solution 
when  this  precipitate  is  decomposed  with  barium  hydrate,  and  after 
removal  of  excess  of  barium  hydrate  is  again  capable  of  precipitation  by 
either  Night  Blue  or  tannin-salt;  (3)  one  which  is  precipitated  by  Night 
Blue,  but  on  decomposing  the  precipitate  with  barium  hydrate,  remains 
insoluble. 

When  wool  undergoes  a  partial  hydrolysis  by  the  prolonged  action  of 
boiling  water  (or  dilute  acid  solutions)  in  the  various  operations  of  washing, 
dyeing,  mordanting,  and  finishing,  so  that  the  fiber  suffers  material  loss 
in  strength  or  elasticity,  it  is  spoken  of  as  "  burnt." 

To  indicate  the  degree  to  which  wool  is  attacked — that  is,  hydrolysed 
or  dissolved  by  the  various  reagents  employed  in  mordanting,  dyeing  and 
carbonising  and  similar  operations,  use  has  been  made  of  the  so-called  biuret 
reaction.^  As  standard,  there  is  prepared  a  colorimetric  scale  by  dissolving 
1  gram  of  wool  yarn  in  caustic  soda,  neutralising  with  hydrochloric  acid, 

1  Fdrber-Zeit.,  1905,  pp.  295  and  314. 

2  Jour.  Soc.  Dyers  &  Col,  1909,  p.  274. 

'  Gelmo  and  Suida,  Ber.  Akad.  Wissensch.  Wien.,  1905. 


REACTIONS  WITH  WATER  AND   STEAM  141 

boiling  to  expel  free  hydrogen  sulfide  and  adding  a  definite  quantity  of 
normal  caustic  soda  and  twentieth-normal  copper  sulfate  to  progressive 
quantities  of  the  wool  solution.  After  standing  one  hour  eleven  violet- 
colored  solutions  of  increasing  depth  of  tint  corresponding  to  a  content 
of  0  to  0.01  gram  of  dissolved  wool  are  obtained.  These  standards  are 
easily  distinguishable  and  comparable,  as  regards  the  extent  of  decomposi- 
tion of  the  fiber  with  the  various  liquors  in  which  the  wool  has  been  treated 
in  the  course  of  any  of  the  operations  mentioned  above.  It  was  found 
that  neutral  soap  had  practically  no  dissolving  effect  on  the  wool  fiber, 
whereas  caustic  alkali  and  alkali  carbonates  dissolve  the  fiber  in  amounts 
roughly  proportional  to  their  concentration,  the  destructive  action  increas- 
ing markedly  with  rise  of  temperature.  In  mordanting  with  bichromate  it 
was  found  that  the  use  of  bichromate  alone,  or  of  equal  parts  of  bichromate 
and  oxalic  acid,  was  considerably  more  destructive  than  bichromate  used 
in  conjunction  with  lactic  acid,  sulfuric  acid,  cream  of  tartar,  or  formic  acid. 
Wool  that  had  been  carbonised — that  is,  impregnated  with  4  percent 
sulfuric  acid  solution  and  dried  at  80°  C.  was  found  to  lose  three  to  four 
times  the  weight  of  fiber  as  compared  with  uncarbonised  wool,  when  the 
two  were  subjected  to  similar  subsequent  treatment  with  dilute  sulfuric 
acid  and  sodium  sulfate.  When  wool  is  heated  in  a  bath  of  stannous 
chloride  slightly  acidified  with  acetic  acid  it  retains  its  natural  color; 
on  the  other  hand,  when  wool  has  been  acted  on  by  an  alkali  a  portion 
of  its  sulfur  was  dissolved  in  the  form  of  alkali  sulfide,  and  a  portion  was 
retained  in  the  fiber  in  the  form  of  an  insoluble  compounds  of  a  sulfide 
nature.  The  latter  when  such  wool  was  treated  with  stannous  chloride, 
as  above,  gives  rise  to  a  brown  coloration  owing  to  the  formation  of  stan- 
nous sulfide,  and  the  depth  of  this  coloration  is  a  rough  index  to  the 
extent  of  the  decomposition  that  has  been  brought  about  by  the  destruc- 
tive action  of  the  alkali  on  the  wool.^ 

When  wool  is  subjected  to  the  action  of  steam  at  100°  C.  it  is  much 
more  rapidly  attacked  than  cotton.  According  to  Scheurer  ^  after  three 
hours'  treatment  with  steam  the  wool  loses  18  percent  in  strength,  after 
six  hours,  23  percent,  after  sixty  hours,  75  percent;  whereas  the  latter 
figure  was  only  reached  by  cotton  after  a  treatment  lasting  four  hundred 
and  twenty  hours. 

Scheurer^  has  made  some  tests  on  the  effect  of  steaming  on  woolen 
cloth;  a  good  quality  of  unbleached  cashmere  cloth,  which  had  been 
previously  washed  with  a  lukewarm  solution  of  soap  and  soda,  was  passed 
lArough  weak  oxalic  acid  and  then  washed  again.  The  steaming  was 
carried  out  at  a  temperature  of  99°  to  100°  C.  for  varying  periods  of  time 

1  Becke,  Fdrher-Zeit.,  1912,  pp.  15  and  66. 

2  Farber-Zeit.,  1893,  p.  290. 

3  Bull  Soc.  Ind.  Mulh.,  1893. 


142 


ACTION   OF   CHEMICAL  AGENTS  ON   WOOL 


and    the    results    as    to    tensile   strength   are   shown   in  the   following 
table : 


Warp. 

Filling. 

Mean. 

Original  cloth 

100 

100 

100 

Steamed    3  hours 

86 

78 

82 

6     "     

80 

75 

77 

12     "     

75 

69 

72 

24     "     

68 

53 

60 

36     "     

62 

37 

50 

48     "     

40 

32 

36 

60     "     

29 

23 

26 

Woodmansey  ^  has  shown  that  wool  loses  much  in  strength  when 
boiled  in  water,  but  much  of  this  strength  returns  on  drying  again.  Wood- 
mansey obtained  the  following  results  on  the  strength  of  strips  of  woolen 
cloth : 

Strength 
in  Pounds. 

Untreated 145.0 

Soaked  1  hour  in  water: 

Tested  wet 104.3 

Air-dried  3  days 140. 3 

Boiled  1  hour  in  water: 

Tested  wet 83.6 

Air-dried  3  days 128.3 

Dry  heat  is  not  as  destructive  to  wool  as  moist  heat,  for  whereas  a 
temperature  of  130°  C.  moist  heat  under  pressure  will  completelj^  disin- 
tegrate wool,  a  much  higher  degree  of  heat  will  only  reduce  the  strength 
slightly  in  the  absence  of  water.     Woodmansey  gives  results  as  follows: 

Strength 
in  Pounds. 

Unheated  wool 145 

Heated  gradually  to  150°  C 141 

Heated  gradually  to  200°  C 135 

Steaming  wool  at  high  temperatures  also  has  the  effect  of  increasing  its 
affinity  for  dyestuffs.  Thus  in  the  process  of  crabbing,  where  the  woolen 
pieces  are  wound  under  high  tension  through  boiling  water  on  to  a  hollow 
perforated  cylinder  and  then  subjected  to  the  action  of  high-pressure 
steam,  the  end  which  is  nearer  the  roller  will  dye  a  deeper  shade  than  the 
1  Jour.  Soc.  Dyers  &  Col,  1918,  p.  228. 


REACTIONS   WITH  WATER  AND  STEAM  143 

outer  portions.  To  avoid  this  defect  it  is  usually  necessary  to  crab  twice 
and  reverse  the  ends. 

The  action  of  water  and  of  hot  moisture  on  wool  is  of  importance 
in  the  processes  technically  employed  for  the  shrinking  of  woolen  fabrics. 
There  are  two  general  processes  in  vogue,  the  ''  London  "  shrunk  and  the 
"  steam  "  shrunk.  The  former  is  the  most  satisfactory  and  the  process  is 
carried  out  by  wrapping  the  cloth,  along  with  a  leader  cloth,  on  a  roller. 
The  leader  has  previously  been  run  through  a  tub  of  cold  water  and 
thoroughly  saturated  or  wet  out.  Rolling  the  two  pieces  of  cloth  together 
causes  the  wet  leader  and  the  dly  cloth  to  be  shrunk  to  form  alternate 
layers,  and  the  dry  cloth  absorbs  the  moisture  from  the  wet  one.  Great 
care  must  be  taken  to  have  the  cloth  rolled  perfect^  even.  After  rolling 
it  is  put  aside  for  some  time  until  the  dry  cloth  has  properly  absorbed  the 
moisture,  and  this  will  vary  with  the  weight  and  structure  of  the  goods. 
The  cloth  is  then  unrolled  and  hung  on  bars  in  a  cool  room  in  which  the 
air  is  circulated,  and  the  goods  are  slowly  dried  to  obtain  the  maximum 
amount  of  shrinkage.  After  drA'ing,  the  cloth  is  pressed  in  hydraulic 
plate  presses  and  should  not  be  pressed  over  rollers.  The  London  process 
if  properly  executed  will  not  injure  the  most  delicate  fabrics  nor  will  it 
start  the  colors.  The  method  of  steam  shrinking  is  quicker  and  cheaper, 
but  it  is  liable  to  injure  the  goods  and  to  start  the  colors  bleeding.  The 
cloth  is  put  on  a  steam-blowing  machine  and  thoroughly  impregnated 
with  steam.  The  goods  are  then  allowed  to  cool  off  and  to  dry  naturally, 
after  which  they  are  finished  in  a  hydraulic  press.  The  steam  process 
also  affects  the  handle  or  feel  of  the  cloth,  but  it  shrinks  the  fabric  quickly 
and  effectively. 

After  a  series  of  carefully  planned  experiments,  Justin-Mueller  ^ 
comes  to  the  conclusion  that  it  is  possible  to  felt  wool  by  heating  in  a  bath 
of  distilled  water  without  agitation  and  at  a  temperature  slightly  below 
the  boiling  point.  The  felting  action  may  be  increased  by  the  addition 
of  acids  and  wall  increase  in  proportion  to  the  quantity  of  acid  used. 
The  felting  action  is  also  more  apparent  when  lime-water  is  used  than 
when  distilled  water  is  employed.  It  is  claimed  that  the  addition  of  acid 
and  continued  boiling  brings  the  fiber  into  the  condition  of  a  ''  gel  "  so 
that  the  fibers  become  cemented  together. 

3.  Acid  and  Basic  Nature  of  Wool. — In  its  chemical  reactions  wool 
appears  to  exhibit  the  characteristics  both  of  an  acid  and  a  base,  and  no 
doubt  it  contains  an  amino  acid  in  its  composition.  The  presence  of  an 
amino  group  is  evidenced  by  the  formation  of  ammonia  as  one  of  the 
decomposition  products  of  wool,  also  by  the  strong  affinit}^  of  wool  for 
the  acid  dyestuffs,  or  even  by  its  ability  to  combine  with  acids  in  general. 

The  acid  nature  of  wool  accounts  for  the  possibility  of  the  formaticn 
1  Zeit.  Farh.  Ind.,  vol.  8,  p.  90. 


144  ACTION  OF  CHEMICAL  AGENTS  ON  WOOL 

of  compounds  of  the  fiber  with  various  metalhc  salts,  alkaHes,  and  metallic 
oxides,  and  therefore  for  the  difference  in  behavior  in  dyeing  between 
wools  which  have  been  scoured  with  alkaline  carbonates  or  treated  with 
metallic  salts  or  hard  water,  and  wool  which  has  not  had  its  acid  groups 
saturated  in  this  way.  It  also  accounts  for  the  fact  that  different  wools 
require  the  addition  of  different  amounts  of  acid  to  the  dye-bath  to  give 
the  same  effect.^ 

The  coefficient  of  acidity,  which  is  a  figure  meaning  the  number  of 
milligrams  of  caustic  potash  neutralised  Ijy  one  gram  of  substance,  has 
been  determined  for  wool,  together  with  a  number  of  other  albuminoids, 
as  follows: 

Wool 57.0         Albumen 20.9 

Silk 143.0         Gelatine 28.4 

Globulin 101.5 

Although  the  amount  of  alkali  absorbed  and  neutralised  by  wool  may  be 
thus  quantitatively  determined,  the  amount  of  acid  absorbed  cannot  be 
so  obtained,  as  wool,  though  it  absorbs  acids,  apparently  does  not  neu- 
tralise them. 

Wool  which  has  been  treated  with  a  dilute  solution  of  caustic  alkali 
apparently  shows  no  difference  from  untreated  wool  in  its  dyeing  proper- 
ties with  respect  to  acid  and  basic  dyes.  That  alkali  lias  been  absorbed 
by  the  wool,  however,  is  shown  by  the  fact  that  it  has  an  increased 
attraction  for  such  dyes  as  Benzopurpurine,  etc.,  which  only  dye  wool 
from  a  slightly  alkaline  bath. 

By  treatment  with  concentrated  solutions  of  caustic  soda  (80°  Tw.) . 
Wool  absorbs  about  50  percent  of  its  weight  of  sodium  hydrate  from  solu- 
tion. Nor  can  this  alkali  be  totally  removed  from  the  wool  by  subse- 
quent washing  with  water  alone,  but  requires  a  treatment  with  acid  for 
complete  neutralisation.  Wool  so  treated  exhibits  a  lessened  affinity  for 
basic  dyes,  showing  a  probable  neutralisation  to  a  greater  or  lesser  extent 
of  its  acid  component. 

In  a  study  of  the  hydrolytic  processes  which  take  place  in  the  dyeing 
of  wool,  Suida-  states  that  the  keratine  of  wool  is  an  albuminoid  that 
readily  undergoes  hydrolysis  whereb}-  the  wool  becomes  amphoteric  (i.e., 
exhibiting  the  qualities  of  both  an  acid  and  a  base).  During  the  first 
period  of  hj'drolysis  there  is  a  rapid  increase  in  acid  properties,  but 
these  then  diminish  and  the  basic  properties  are  retained  to  the  end 
because  the  final  products  contain  either  guanidyl  or  imidazole  groups. 
It  seems  probable  that  in  dyeing  or  mordanting,  the  acid  or  base 
combines  directly  with  the  basic  or  acid  group  of  the  wool  to  form  an 

'  See  experiments  of  Gelmo  and  Suida,  Bcr.  Akad.  Wissenschafter},  IMaj',  1905. 
2  Zeit.  angew.  Chem.,  1909,  p.  2131. 


ACID  AND   BASIC   NATURE   OF   WOOL  145 

insoluble  salt.  Wool  is  not  dyed  appreciably  when  it  is  treated  in  a 
neutral  bath  with  the  sodium  salt  of  a  dye  acid  because  the  acid  groups 
of  wool  are  not  able  to  decompose  the  more  stable  salt.  Wool,  however, 
is  dyed  by  an  aqueous  solution  of  an  acid  dye,  and  in  this  case  the 
basic  groups  of  the  wool  unite  directly  with  the  acid  dye  to  form  an 
insoluble  salt.  Wool  is  dyed  intensively  when  treated  with  the  hydro- 
chloride of  a  basic  dye;  in  this  case  the  hydrochloric  acid  of  the  dye  salt 
probably  combines  with  basic  groups  of  the  wool  and  the  dye  itself  com- 
bines with  acid  groups;  although  it  must  be  remembered  that  a  hydrol- 
ysis of  the  wool  is  taking  place,  and  therefore  quite  an  appreciable  quan- 
tity of  it  passes  into  solution  and  unites  with  the  hydrochloric  acid  of  the 
dye  salt.  This  accounts  for  the  fact  that  all  of  the  chlorine  is  found  in 
the  dyebath,  which  also  gives  the  biuret  reaction  very  readily.  Wool 
is  also  dyed  on  being  treated  in  an  acid  bath  with  the  sodium  salt  of  a  dye 
acid  or  with  the  dye  acid  itself.  The  acid  in  the  bath  aids  the  hydrolysis  of 
the  wool,  and  combines  with  one  of  its  cleavage  products,  while  the  acid 
dye  combines  with  basic  groups  of  the  wool.  On  the  other  hand,  wool 
is  not  dyed  in  an  acid  solution  of  a  salt  of  a  basic  dye,  for  in  this  case  the 
dye  base  is  not  set  free  and  cannot  combine  with  the  acid  groups  of  the 
wool.  Since  in  the  hydrolysis  of  wool  the  basic  groups  eventually  become 
more  prominent  it  is  easy  to  understand  that  acid  dyes  act  longer  upon 
wool  and  produce  more  solid  colors. 

Becke  ^  states  that  the  stannous  chloride  reaction  gives  only  partial 
information  concerning  the  injury  done  to  wool  fibers  by  alkaline  solu- 
tions. The  biuret  reaction,  however,  he  says,  yields  accurate  numerical 
data  on  the  quantity  of  wool  substance  dissolved  by  acids,  alkalies,  soaps 
and  such  like.  There  is  a  close  relation  between  the  loss  by  solution  of 
wool  substance  thus  determined  and  the  tensile  strength  and  elasticity 
of  the  wool  yarn.  In  this  connection  it  appears  that  sulfuric  acid  has  a 
marked  hydrolysing  action  on  wool.  The  basic  substances  formed  dis- 
solve in  the  acid  solution,  while  the  acid  products  are  dissolved  readily 
by  subsequent  alkaline  treatment.  Becke  also  states  that,  contrary 
to  the  prevailing  opinion  that  dyeing  in  acid  baths  is  least  injurious  to 
wool,  dyeing  with  sulfuric  acid  and  glaubersalt  or  with  sodium  bisulfate 
is  quite  harmful,  as  it  renders  the  wool  susceptible  to  attack  by  sub- 
sequent treatment  with  water,  soap,  soda  ash  or  other  alkalies.  Becke's 
opinions  in  this  matter,  however,  need  to  be  further  confirmed  by  exact 
tests  before  they  can  be  accepted. 

Vignon  ^  has  experimented  on  the  amount  of  heat  disengaged  by 
treating  wool  with  different  acids  and  alkalies,  with  the  following  results, 
using  100  grams  of  unbleached  wool: 

1  Farber  Zeitung,  vol.  30,  p.  128. 

2  Compt.  rend.,  1890,  No.  17. 


146 


ACTION   OF   CHEMICAL   AGENTS  ON   WOOL 


Reagent.  Calories  Liberated. 

Potassium  hydrate  (normal) 24.50 

Sodium  hydrate  (normal) 24 .  30 

Hydrochloric  acid  (normal) 20 .  05 

Sulfuric  acid  (normal) 20 .  90 

These  figures  are  interesting  in  indicating  the  relative  acidity  and  alka- 
linity of  the  wool  fiber. 

4.  Action  of  Acids  on  Wool. — When  treated  with  dilute  acids,  the 
wool  fiber  does  not  appear  to  undergo  any  appreciable  change;  although, 
from  the  fact  that  acids  are  very  readily  absorbed  by  wool  and  very 
tenaciously  held  by  it,  there  is  i-eason  to  believe  that  some  chemical  com- 
bination takes  place  between  the  fiber  and  the  acid.  It  can  be  shown, 
for  example,  that  if  wool  be  treated  with  dilute  sulfuric  acid,  all  of  the 
acid  cannot  again  be  extracted  b}^  boiling  in  water  until  the  washwaters 
are  perfect^  neutral;  and  wool  thus  prepared  has  the  power  of  combining 
with  the  various  acid  colors  without  the  necessity  of  adding  any  acid  to 
the  dye-bath.  Fort  and  Llo3-d  ^  came  to  the  conclusion  that  some  acid 
was  retained  permanently  by  the  wool  fiber  even  under  continued  extrac- 
tion with  boiling  water.  Harrison ,2  however,  from  experiments  in  which 
twenty-four  consecutive  washings  were  used,  came  to  the  conclusion  that 
all  of  the  acid  could  be  removed  by  simply  washing  and  consequently 
there  was  no  evidence  of  an}-  chemical  combination  between  the  fiber 
and  the  acid.  The  following  table  shows  the  relative  absorption  of 
suKuric  acid  from  its  solutions  by  wool  (Mills  and  Takamine) : 


Percent  Acid 

Percent  Left  in 

Percent  Absorbed 

Used. 

Solution. 

by  Wool. 

2i 

0.38 

2  12 

5 

2.17 

2.83 

10 

6.37 

3.63 

20 

15.87 

4.13 

40 

35.18 

4.82 

Mills  and  Takamine  also  give  the  equivalent  absorption  of  wool  and 
silk  for  different  acids  and  ammonia,  as  follows: 


Sulfuric  Acid. 

Hydrochloric  Acid. 

Ammonia. 

Wool 

Silk 

2.2 
2.0 

2.0 
1.0 

1.0 
6.4 

Silk,  therefore  is  more  acid  in  character  than  wool. 
^Jnur.  Soc.  Dyers  &  Col.,  1914,  p.  5. 
^Jour.  Soc.  Dyers  &  Col,  1917,  p.  57. 


ACTION  OF  ACIDS  ON  WOOL 


147 


Wool  that  has  been  treated  with  warm  dilute  solutions  of  sulfuric  acid 
not  only  shows  an  increased  affinity  for  acid  colors,  but  also  a  decreased 
affinity  for  basic  colors.  Alcoholic  solutions  of  sulfuric  acid  appear  to  act 
more  effectively  in  this  respect  than  the  aqueous  solution.  According 
to  Gillet  ^  the  acid  which  is  fixed  in  wool  may  be  removed  by  treatment 
with  a  dilute  solution  of  soda  ash  and  the  wool  will  then  regain  its  original 
d3^eing  properties.  Gelmo  and  Suida  confirm  this  but  use  ammonium 
carbonate.  Acidified  wool  also  shows  an  increased  power  of  dyeing 
alizarine  colors  direct. 

Other  acids  have  about  the  same  effect  on  wool  as  sulfuric  acid,  only 
in  the  case  of  acetic  acid  it  is  necessary  to  add  the  acid  directly  to 
the  dj^e  bath  in  order  to  hinder  the  fixation  of  basic  colors  or  increase  the 
absorption  of  acid  colors.^  It  is  also  true  that  if  wool  which  has  been 
treated  with  sulfuric  acid  is  boiled  in  water,  ammonium  sulfate  is  to  be 
found  in  the  solution,  showing  that  some  chemical  action  has  probably 
taken  place  between  the  acid  and  some  basic  constituent  of  the  wool  fiber. 

Hydrochloric  acid  acts  much  in  the  same  manner  as  sulfuric  acid, 
although  the  amount  permanently  absorbed  by  the  fiber  is  quite  small, 
most  of  the  acid  being  removed  by  boiling  water. 

Mills  and  Takamine  ^  have  studied  the  relative  absorption  of  mixed 
acids  on  the  fibers,  as  follows : 


Ratio. 
H2SO4  :  HCl. 

Wool. 

Silk. 

H2SO4. 

HCl. 

H2SO4. 

HCl. 

1  :  1 
1  :  2 
1  :4 

5.0 
11.3 
16.6 

32.5 
25.5 

18.4 

6.6 
5.0 
4.0 

0.87 

2.5 

3.5 

The  rate  of  absorption  of  these  acids  when  present  in  the  ratio  of 
H2SO4  :  4HC1  was  as  follows: 


Fiber. 

H2SO4. 

HCl. 

Wool 

100 
100 

179.6 
175.0 

Silk 

1  Rei'.  Gen.  Mat.  Col,  1899,  p.  157. 

^See  Gelmo  and  Suida,  Ber.  Akad.  Wissenschnften,  May,  1905. 

^Jour.  Chem.  Soc,  1883,  p.  144. 


148  ACTION  OF  CHEMICAL  AGENTS  ON  WOOL 

The  maximum  absorption  for  silk  and  cotton  was: 


Reagent. 


H2SO4 
HCl.  . 
NaOH 


Cotton. 


Silk. 


2.6 

2.2 

2.2 


When  wool  is  treated  with  weak  reagents  separately  in  the  proportion 
HCl  :  NaOH,  the  absorption  is  in  the  ratio  2HC1  :  3NaOH.  With  silk 
and  cotton  the  ratio  is  3HC1  :  lONaOH. 

Chromic  acid  is  absorbed  in  like  manner,  and  no  doubt  the  usefulness 
of  bichromates  as  mordants  for  wool  depends  somewhat  on  the  chemical 
combination  between  the  fiber  and  the  chromic  acid. 

With  nitric  acid  wool  behaves  somewhat  differently,  for  unless  the 
acid  be  very  dilute  and  the  temperature  low,  the  fiber  will  assume  a  yellow 
color,  which  is  probably  due  to  the  formation  of  xanthoproteic  acid. 
Formerly  this  yellow  color  was  supposed  to  be  due  to  the  formation  of 
picric  acid,  but  this  view  is  erroneous.  Nitric  acid  has  a  similar  effect 
on  the  skin,  the  yellow  stains  which  it  produces  being  a  subject  of  common 
experience.  If  the  strength  of  the  acid  is  below  4°  Tw.,  the  yellow  colora- 
tion on  wool  is  not  very  marked,  and  in  this  manner  nitric  acid  has  been 
largely  employed  as  a  stripping  agent,  especially  for  shoddies. 

When  treated  by  the  prolonged  action  of  boiling  dilute  acids,  wool 
undergoes  some  decomposition  which  may  be  carried  out  to  complete 
solution  of  the  fiber  when  boiled  under  pressure,  as,  for  instance,  by 
heating  with  dilute  hydrochloric  acid  (1:5)  to  190°  C. 

Georgievics  and  PoUak  have  recently  brought  out  some  work  in  regard 
to  the  study  of  the  absorption  of  acid  by  wool.  It  seems  that  the  absorp- 
tion of  acid  by  the  wool  fiber  is  shown  to  be  a  natural  adsorption  process. 
With  the  acid  used  adsorption  is  found  to  proceed  irregularly  in  the  case 
of  the  weaker  solutions,  but  with  solutions  containing  0.5  gram  of  acid 
and  upward  in  250  c.c.  of  water,  the  adsorption  can  be  expressed  by 
formulas,  and  diagrams  of  curves  are  given  in  illustration.  Ignoring  the 
results  obtained  with  the  weaker  solution,  and  taking  molecular  propor- 
tions of  the  acid,  the  order  of  adsorption  was  found  to  be  as  follows: 
Nitric,  hydrochloric,  oxalic,  sulfuric,  formic,  succinic,  adipic  and  acetic. 
Nitric  acid  was  the  most  adsorbed  and  acetic  acid  the  least.  Mineral 
acids  are  in  general  adsorbed  to  a  greater  extent  than  fatty  acids,  but  the 
reverse  is  the  case  when  charcoal  is  the  absorbent  material.  It  was 
found  that  as  the  strength  of  the  acid  solution  increased  the  relative  amount 
taken  up  by  the  wool  decreased,  and  in  every  case,  above  a  certain  concen- 


ACTION  OF  ACIDS  ON   WOOL  149 

tration  (about  0.5  gram  of  acid  per  250  cc.  of  solution)  the  distribution 
of  the  acid  between  the  fiber  and  the  solution  follows  the  general  formula : 

where  Cs  and  C/  represent  the  quantity  of  acid  in  grams  in  the  solution 
and  fiber  respectively,  and  x  and  K  are  constants  which  are  different  for 
the  different  acids.  For  hydrochloric  acid  x  =  5  and  iC==  0.293,  while 
for  acetic  acid  the  values  are  a;  =1.75  and  /v  =  0.545.  A  formula  of  this 
type  is  characteristic  of  all  adsorption  phenomena.  Further  experiments 
on  this  subject  by  Georgievics,  however,  show  that  in  the  case  of  very 
dilute  solutions  the  taking  up  of  the  acid  by  the  wool  is  a  solution  phenom- 
enon and  not  one  of  adsorption;  but  in  the  case  of  stronger  solutions 
the  solution  factor  is  overshadowed  by  that  of  adsorption. 

The  present  results  agree  with  those  obtained  formerly  b}^  Walker 
and  Appleyard  on  the  adsorption  of  acid  by  silk.  No  relation  could  be 
found  between  the  adsorption  of  an  acid  and  the  degree  of  dissociation  of 
its  solution.  The  adsorption  of  acid  by  wool  was  found  to  be  but  little 
dependent  on  the  temperature.  Usually  a  little  less  was  adsorbed  at  the 
higher  temperatures.  The  adsorption  of  an  acid  is  decidedly  affected 
by  the  presence  of  another  acid,  and  in  varying  ways.  For  example,  the 
adsorption  of  sulfuric  acid  from  very  dilute  solutions  is  slight!}^  increased, 
but  decidedly  diminished  in  stronger  solutions,  by  the  presence  of  hydro- 
chloric acid,  while  the  adsorption  of  hydrochloric  acid  from  all  concen- 
trations is  lessened  by  the  presence  of  sulfuric  acid.  The  adsorption  of 
acid  by  wool  from  a  solution  of  a  mixture  of  acid  is  less  than  from  an 
equivalent  quantity  of  a  single  acid.  This  excludes  the  possibility  of  a 
simple  salt  formation  between  the  fiber  substance  and  the  acid. 

Fort  and  Lloyd  ^  have  also  studied  the  adsorption  of  acids  by  wool. 
A  comparative  series  of  experiments  was  made,  giving  a  range  of  treat- 
ments from  1  to  12  percent  of  acid,  and  using  hydrochloric,  sulfuric,  oxalic, 
formic  and  acetic  acids.  The  results  of  the  acid  absorbed  and  that  per- 
manently retained  after  a  series  of  washings  with  hot  water  are  shown  in 
the  table  on  page  150. 

If  curves  are  drawn  representing  these  results  there  will  be  found  dis- 
tinct nodes  where  a  higher  amount  of  acid  is  used  and  yet  the  amounts 
absorbed  and  permanently  retained  by  the  fiber  are  actually  less.  It  is 
probable  that  at  these  points  the  wool  is  undergoing  changes  by  hydrol- 
ysis, and  the  hydrolysed  wool  products  are  combining  with  the  acid. 

Richards  ^  has  shown  that  by  the  action  of  nitrous  acid,  wool  is  diazo- 
tiscd  in  a  manner  similar  to  an  amino  compound,  and  may  be  developed 

1  Jour.  Soc.  Dijers  &  Col,  1914,  p.  5. 
-Jour.  Soc.  Chan.  IruL,  1888,  p.  841. 


150 


ACTION  OF  CHEMICAL  AGENTS  ON  WOOL 


HydrochloricAcid. 

Sulfuric  Acid. 

Oxalic  Acid. 

Acetic  Acid. 

Formic  Acid. 

Per- 

cent 

Perma- 

Perma- 

Perma- 

Perma- 

Perma- 

Acid 

Ab- 

nently 

Ab- 

nently 

Ab- 

nently 

Ab- 

nently 

Ab- 

nently 

Used. 

sorbed, 

Re- 

sorbed, 

Re- 

sorbed, 

Re- 

sorbed, 

Re- 

sorbed, 

Re- 

Percent. 

tained, 
Percent. 

Percent. 

tained, 
Percent. 

Percent. 

tained, 
Percent. 

Percent. 

tained, 
Percent. 

Percent. 

tained, 
Percent. 

1 

0.97 

0.63 

0.97 

0.78 

0.94 

0.72 

0.73 

0.63 

0.33 

0.15 

2 

1.51 

0.58 

1.90 

1.48 

1.72 

0.95 

0.94 

0.73 

0.71 

0.34 

3 

1.97 

0.71 

2.67 

1.76 

2.46 

0.94 

0.97 

0.72 

0.95 

0.54 

4 

2.32 

0.78 

3.58 

2.12 

3.16 

1.33 

0.35 

1.06 

1.35 

0.83 

5 

2.25 

0.61 

3.48 

1.97 

3.62 

1.51 

1.27 

0.91 

k.51 

0.86 

6 

2.40 

0.72 

3.86 

1.90 

4.06 

1.31 

1.19 

0.83 

1.78 

1.16 

7 

2.47 

0.63 

3.72 

2.09 

4.67 

1.53 

1.09 

0.68 

1.58 

0.64 

8 

2.71 

0.76 

3.80 

2.04 

5.16 

1.78 

1.25 

0.70 

1.55 

0.65 

9 

2.40 

0.51 

3.62 

1.92 

5.03 

1.53 

1.30 

0.68 

1.71 

0.71 

10 

2.58 

0.61 

3.79 

2.00 

5.16 

1.39 

1.39 

0.73 

1.48 

0.55 

11 

2.81 

0.74 

4.17 

2.23 

5.61 

1.71 

1.41 

0.78 

1.81 

0.65 

12 

2.69 

0.61 

4.06 

2.03 

5.77 

1.47 

1.40 

0.64 

1.54 

0.56 

subsequently  in  an  alkaline  solution  of  a  phenol,  giving  rise  to  quite  a 
variety  of  shades.  According  to  Prud'homme  ^  instead  of  a  diazo  body 
there  is  formed  a  nitrosamine,  and  he  cites  the  behavior  of  wool  with 
formaldehyde  and  with  sulfurous  acid  to  show  the  absence  of  an  animo 
compound.  Flick  agrees  with  this  view  while  Grandmougin  and  Bourry 
object  to  the  proof  of  Prud'homme  as  being  only  a  negative  indication 
and  leaving  the  question  as  to  the  existence  of  an  amino  or  an  imino 
group  still  an  open  one.  According  to  Emil  Fischer  a  diazotisation  of 
wool  is  not  regarded  as  possible.^ 

When  wool  is  treated  in  the  dark  with  an  acid  solution  of  sodium  nitrite 
(6  percent)  it  quickly  acquires  a  pale-yellow  color,  rapidly  changing  on 
exposure  to  light.  Wool  prepared  in  this  manner  is  turned  brown  by  boil- 
ing water,  and  caustic  soda  effects  the  same  change,  the  color  becoming 
yellow  again  on  treatment  with  acids.  Stannous  chloride  in  a  warm  solu- 
tion discharges  the  brown  color.  Diazotised  wool  appears  to  have  an 
increased  attraction  for  basic  dyes  and  a  lessened  affinity  for  the  acid 
dyes.  Exposure  to  light  bleaches  diazotised  wool,  which  is  then  turned 
orange  by  alkalies,  and  not  brown.  The  following  colors  may  be  obtained 
by  treating  diazotised  wool  with  various  phenols  in  alkaline  solution : 


Phenol. 

Color. 

Reaction  with  H2SO4. 

Resorcin 

Orange 

Pale  red 

Orcin 

Orange 

Pale  red 

Pyrogallol 

Yellowish  brown 

Orange 

Phloroglucol 

Bordeaux 

No  change 

Alpha-naphthol 

Red 

Black 

Beta-naphthol 

Red 

Pale  red 

1  Fdrb.  Zeit.,  1898,  p.  346. 

2  See  also  Brandt,  Farb.  Zeit., 

1901,  p.  238;    Kayser, 

Zeit.  Farb.,  Ind.,  1903,  p 

and  Justin  Mueller,  Rev.  Gen. 

Mat.  Col,  1902,  p.  67,  on 

this  subject. 

80; 


ACTION  OF  ACIDS  ON  WOOL  151 

When  dyed  in  connection  with  metalhc  mordants,  these  phenol  colors 
are  fast  to  light,  fulling,  acids,  and  boiling  water.  Tin  mordants  give 
yellow  and  orange  shades;  aluminium,  orange;  iron,  dark  browns  and 
olive  browns;  chromium  and  copper,  garnet.  Wool  treated  with  nitrous 
acid  acquires  a  harsh  feel  and  is  non-hygroscopic.  It  also  appears  to  have 
an  increased  affinity  for  basic  dyes.^ 

The  acid  number  of  diazotised  wool  is  169,  and  its  iodine  number 
4.7,  whereas  untreated  wool  has  the  numbers  88  and  18.4,  respectively. 
Diazotised  wool  also  appears  to  contain  less  nitrogen  than  ordinary  wool.^ 

In  common  with  most  other  organic  substances,  wool  is  totally  destroj'ed 
by  the  action  of  concentrated  mineral  acids.  On  treatment  with  cold 
concentrated  sulfuric  acid  for  a  short  time  wool  is  not  seriously  disinte- 
grated; the  fiber,  however,  suffers  a  change  in  that  it  loses  all  affinity  for 
acid  dyes,  while  it  strongly  attracts  basic  dyes. 

This  reaction  does  not  seem  to  have  met  with  any  commercial  applica- 
tion,^ as  it  would  have  to  be  operated  with  extreme  care  to  avoid  weakening 
and  injury  to  the  wool.  The  acid  used  in  the  Badische  patent  is  60°  to 
62°  Be.  Becke  and  Beil  (Ger.  Pat.  168,026)  by  using  a  stronger  acid 
(98^  per  cent  H2SO4)  obtain  better  effects  and  at  the  same  time  avoid  the 
danger  of  injuring  the  wool.  Instead  of  washing  the  treated  wool  directly 
with  water  (which  results  in  strong  heating  and  tendering  of  the  fiber) 
it  is  washed  first  in  a  diluted,  and  if  necessary  cooled,  sulfuric  acid.  The 
first  wash  is  with  95  percent  acid,  the  second  with  90  percent  acid,  and  so 
on  till  the  tenth  bath  is  of  10  percent  acid,  and  the  eleventh  bath  is  pure 
water.     Such  a  process,  however,  would  hardly  be  of  any  practical  value. 

Knecht  has  found  that  by  boiling  wool  with  moderately  concentrated 
sulfuric  acid  (2  parts  sulfuric  acid  to  3  parts  water)  the  fiber  is  dissolved 
with  the  formation  of  lanuginic  acid  and  other  amino  bodies  as  well  as 
ammonia  and  sulfuretted  hydrogen.  Other  mineral  and  organic  acids 
have  the  same  effect. 

Grandmougin  "*  calls  attention  to  the  fact  that  this  effect  of  concentrated 
sulfuric  acid  is  shared  by  many  other  chemicals,  such  as  caustic  soda, 
phosphoric  acid,  nitric  acid  followed  by  tin  chloride,  zinc  chloride,  calcium 
chloride,  sulfocyanides,  bisulfites,  hydrosulfites,  resorcinol,  tartaric  acid, 
and  citric  acid.  All  of  these  in  concentrated  solutions,  either  cold  or  by 
steaming,  effect  the  affinity  of  wool  for  acid  dyes,  and  also  may  be  used 
for  the  production  of  crepe  effects  in  printing. 

With  organic  acids,  wool  is  usually  reactive,  readily  absorbing  oxalic, 
lactic,  tartaric,  acetic,  etc,  acids.     Tannic  acid,  however,  is  an  exception, 

»  Bull.  Soc.  Ind.  Mulh.,  1899,  p.  221. 
2Lidow,  Chem.  Centr.,  1901,  p.  703. 
3  See  Badische  Co.,  Fr.  Pat.  318,741. 
*Zeit.  Farb.  Ind.,  1906,  p.  223. 


152  ACTION   OF  CHEMICAL  AGENTS  ON  WOOL 

and  is  not  absorbed  to  any  extent  by  the  fiber.  But  if  wool  is  treated  in  a 
boiling  solution  of  tannic  acid  and  the  latter  fixed  in  the  hber  l)y  a  sub- 
sequent treatment  in  a  solution  of  tartar  emetic,  stannous  chloride,  or 
other  suitable  metallic  salt,  it  will  be  found  that  the  fiber  becomes  altered 
in  such  manner  that  it  no  longer  exhibits  its  normal  affinity  toward  acid, 
substantive,  and  mordant  dyes.  Toward  basic  dyes,  however,  the  affinity 
of  the  wool  becomes  considerably  increased  by  reason  of  the  presence  of 
tannin. 

This  reaction  is  the  basis  of  applying  the  so-called  ''  resist  "  process  to 
the  dyeing  of  wool.  Worsted  or  woolen  yarn  is  treated  with  a  solution  of 
tannic  acid,  and  then  with  one  of  stannous  chloride.  The  treated  yarn  is 
then  woven  with  untreated  yarn,  and  the  fabric  dyed  in  the  piece  with 
various  colors  which  have  little  or  no  affinity  for  the  treated  fiber,  but 
show  their  normal  dyeing  properties  toward  the  untreated  wool.  Such 
dyes  are  known  as  "  resist  "  colors  for  this  process.  A  number  of  one- 
bath  or  after-chromed  alizarine  or  mordant  dyes  are  suitable  for  this 
purpose. 

This  process  was  introduced  by  Becke  and  Beil  ^  and  is  also  applicable 
to  some  extent  to  silk  as  well  as  to  wool.  The  details  of  the  process 
are  given  as  follows  (Farbw.  Hochst):  (1)  For  the  preparation  of  a  full 
reserve:  (a)  for  acid  dyes  and  white,  treat  the  wool  with  10  percent  (on 
weight  of  the  wool)  of  tannic  acid  and  4  percent  of  formic  acid  (85  percent) 
and  50  parts  of  water,  boil  for  one  hour,  then  cool  to  160°  F.  and  add  3 
percent  stannous  chloride,  and  work  for  one-half  hour  at  160°  F.,  then 
wash  and  dry.  The  treatment  with  stannous  chloride  may  also  be  carried 
out  in  a  fresh  bath  with  the  addition  of  1  percent  of  formic  acid;  (b)  for 
fast  colors  the  wool  may  be  previously  dyed  with  vat  or  mordant  dyes 
in  the  usual  manner  and  then  "  prepared  "  in  a  fresh  bath  as  above.  For 
the  production  of  uniform  results  the  dilution  of  the  bath  must  be  large 
and  the  time  of  operation  long;  iron  apparatus  is  not  suit:ible  for  use, 
and  if  copper  apparatus  is  used,  an  addition  of  2  percent  of  ammonium 
sulfocyanide  is  necessary.  (2)  Preparation  for  half  reserve:  use  a  bath 
containing  10  percent  of  tannin  and  4  percent  of  formic  acid,  work  one 
hour  at  the  boil;  then  without  rinsing  enter  a  second  bath  containing  at 
first  only  water,  and  after  standing  for  some  time  add  6  percent  of  tartaric 
acid  and  5  percent  of  sodium  acetate;  work  for  one-half  hour  at  200°  F., 
and  wash. 

When  wool  is  treated  with  acetic  anhydride  in  the  presence -of  an  acid 
catalyst,  particularly  sulfuric  acid,  it  retains  its  physical  properties  but 
permanently  resists  the  dyeing  action  of  acid  colors.^ 

1  Ger.  Pat.  137,947;  see  also  Zeit.  Farb.  Ind.,  1906,  p.  62. 

2  See  Munz  and  Haynn,  Chem.  Zeit.,  1922,  p.  895. 


ACTION   OF  ALKALIES   ON  WOOL 


L53 


5.  Action  of  Alkalies  on  Wool. — Although  so  resistant  to  the  action  of 
acids,  on  the  other  hand,  wool  is  quite  sensitive  to  alkalies  (see  Fig.  75); 
so  much  so,  in  fact,  that  a  5  percent  solution  of  caustic  soda  at  a  boiling 
temperature  will  completely  dissolve  wool  in  a  few  minutes.  From  this 
fact  it  is  easy  to  understand  why  soaps,  and  scouring  and  fulling  agents 
in  general,  should  be  free  from  appreciable  amounts  of  caustic  alkalies. 
The  weaker  alkaline  salts,  such  as  the  carbonates,  soaps,  etc.,  are  not  so 
destructive  in  their  action,  and  when  employed  at  moderate  temperatures 


Fig.  75. — Wool  Fiber  Treated  with  Caustic  Soda  Solution,  Showing  Extreme  Swelling 

and  Gradual  Decomposition, 


they  are  not  regarded  as  deleterious,  and  are  largely  used  in  scouring  and 
fulling.  With  respect  to  the  amount  of  caustic  alkah  necessary  to  decom- 
pose wool,  Knecht  found  that  on  boiling  wool  for  three  hours  with  3  percent 
(on  the  weight  of  the  wool)  of  caustic  soda  the  fiber  was  not  disintegrated, 
but  on  increasing  the  amount  to  6  percent  complete  disintegration  took 
place  and  the  wool  was  almost  entirely  dissolved. 

The  action  of  concentrated  solutions  of  caustic  alkalies  on  wool  is  a 
rather  peculiar  one.  Solutions  of  caustic  soda  of  a  strength  below  75°  Tw. 
will  rapidly  disintegrate  the  fiber,  but  with  solutions  of  75°-100°  Tw.  the 
fiber  is  no  longer  disintegi-ated,  but,  on  the  other  hand,  increases  from 


154 


ACTION  OF  CHEMICAL  AGENTS  ON  WOOL 


25  to  35  percent  in  tensile  strength,  becomes  quite  white  in  appearance, 
and  acquires  a  high  luster  and  a  silky  scroop.  The  maximum  effect  is 
obtained  by  using  a  caustic  soda  solution  of  80°  Tw.  and  keeping  the 
temperature  below  20°  C.^  The  duration  of  the  treatment  should  not 
be  more  than  five  minutes.  Buntrock  shows  the  effect  of  different  con- 
centrations of  caustic  soda  on  the  strength  of  wool  as  follows: 


Solution. 

Tensile  Strength 
in  Grams. 

Solution. 

Tensile  Strength 
in  Grams. 

Untreated  wool 

610 

NaOHof  32°  Be 

420 

NaOHof    4°  Be 

510 

36°  Be 

580 

8°  Be 

47.5 

40°  Be 

770 

12°  Be 

2.50 

42°  Be 

815 

16°  Be 

180 

44°  Be 

740 

20°  Be 

9.5 

"        48°  Be 

720 

24°  Be 

200 

50°  Be 

620 

28°  Be 

240 

There  consequently  appears  to  be  a  minimum  point  at  20°  Be.  and  a 
maximum  point  at  42°  Be.,  although  even  at  50°  Be.  the  strength  is 
greater  than  the  original  untreated  wool.  Buntrock  also  shows  the  effect 
of  adding  glycerol,  using  100  parts  of  caustic  soda  solution  of  20°  Be  and 

25  parts  of  glycerol  gave  strength  of  550  grams 

50  "  "  "  730      " 

75  "  "  "  700      " 

100  "  "  "  700      " 

Without  glycerol  gave  strength  of  95      " 

The  addition  of  glycerol  to  the  solution  of  caustic  soda  renders  the 
action  of  the  alkali  more  effective.  Wool  treated  in  this  manner  may  be 
said  to  be  "  mercerised,"  though  the  action  of  the  caustic  soda  in  this 
case  is  not  quite  analogous  to  that  in  the  mercerisation  of  cotton.  From 
the  decrease  in  the  density"  of  the  caustic  soda  solutions  employed,  it  has 
been  shown  that  the  wool  absorbs  a  considerable  amount  of  sodium 
hydrate  from  solution.  Whether  this  alkali  is  held  by  the  wool  in  true 
chemical  combination  has  not  been  ascertained.  The  treated  wool 
contains  but  a  small  amount  of  sulfur  compared  with  that  present  in  the 
original  fiber;  analysis,  in  fact,  shows  that  only  about  15  percent  of  the 
original  sulfur  remains  in  the  mercerised  wool.  The  dyeing  qualities 
of  the  latter  are  also  different  from  the  original  fiber  in  that  it  absorbs 
more  dyestuff  from  solution  and  hence  yields  heavier  shades.  Quantita- 
1  Matthews,  Jour.  Soc.  Chem.  Ind.,  1902,  p.  685. 


ACTION  OF  ALKj\.LIES  ON  WOOL  155 

tive  tests  have  shown  that  the  increase  in  the  absorption  of  dyestuffs  is  as 
follows : 

Class  of  Dyestuffs.  r>         4. ' 

i  GrCGIlu. 

Basic 12.5 

Acid 20.0 

Substantive 25 . 0 

Mordant 33 .3 

Mercerised  wool  also  shows  an  increased  absorption  with  respect  to 
solutions  of  various  metallic  salts. 

Crepon  effects  may  be  obtained  on  union  goods  (of  wool  and  cotton 
yarns)  by  the  action  of  strong  caustic  soda,  which  exercises  a  strong 
shrinking  action  on  the  cotton  while  not  materially  affecting  the  wool. 
A  caustic  soda  solution  of  about  50°  Tw.  is  used  at  a  temperature  under 
50°  F.,  and  the  time  of  immersion  should  not  be  more  than  one-third 
minute.  Excess  of  caustic  is  then  squeezed  out,  and  the  goods  are  neu- 
tralised by  passage  through  a  fairly  strong  (30  grams  of  sulfuric  acid  per 
liter)  but  cold  acid  bath.  By  suitable  weaving  various  pattern  effects  may 
be  obtained. 

The  method  of  treating  wool  with  strong  alkalies  for  the  purpose  of 
increasing  the  affinity  of  the  fiber  for  dyes  is  suggested  as  a  means  of 
obtaining  two-colored  effects  in  wool  printing.^  The  following  recipe 
was  recommended  for  practical  work:  Print  the  goods  with  a  mixture  of 
400  parts  of  caustic  soda  solution  (75°  Tw.),  400  parts  of  tragacanth 
solution  (1  :  1000),  75  parts  of  British  gum,  and  150  parts  of  glycerol. 
After  printing,  wash  without  previous  drying  and  then  dye.  It  is  also 
said  to  be  advisable  to  pass  the  goods  through  a  bath  containing  50  lbs. 
of  ammonia  per  100  gallons.  Knecht,^  however,  states  that  this  method 
does  not  give  satisfactory  results,  but  on  investigation  finds  that  the 
following  printing  recipe  is  satisfactory:  Print  the  goods  with  a  mixture 
of  100  parts  of  caustic  soda  solution  of  80°  Tw.  and  100  parts  of  British 
gum  (1  :  1).     This  treatment  gives  excellent  results  with  the  acid  dyes. 

Chevreul  showed  that  wool  treated  to  the  action  of  lime  in  a  cold 
solution  and  without  access  of  air  takes  up  dyes  more  readil}'  than  untreated 
wool.  Guignet  and  David  ^  find  this  property  is  general  for  all  ordinary 
dyes.  The  effect  is  obtained  by  treating  the  wool  skeins  of  fabric  with 
a  milk  of  lime  solution  containing  0.5  lb.  slacked  lime  for  100  lbs.  of  wool. 

A  product  known  as  "  Protectol  "  has  recently  been  introduced  in 
Germany  as  a  substance  for  the  treatment  of  wool  so  as  to  protect  the 
fiber  against  the  destructive  action  of  alkalies.     By  the  addition  of  this 

1  Cassella  &  Co.,  1898. 

2  Jour.  Soc.  Dyers  &  Col,  1898,  p.  99. 
»  Compt.  rend.,  vol.  128,  p.  686. 


156  ACTION   OF  CHEMICAL  AGENTS  ON   WOOL 

material  to  any  bath  containing  caustic  soda,  it  is  said  to  be  possible  to 
treat  wool  in  such  a  bath  without  injury  to  the  fiber.  It  is  being  employed 
considerably  in  the  dyeing  of  sulfur  colors  on  mixtures  of  wool  and  cotton, 
the  wool  being  thus  protected  from  the  corrosive  action  of  the  sodium  sulfide 
in  the  dye-bath.  Protectol  is  a  by-product  obtained  from  the  waste  sulfite 
liquors  in  cooking  wood-pulp.  It  probably  consists  largely  of  the  sodium 
salt  of  lignin  sulfonate. 

Schneider  ^  states  that  when  woolen  yarn  is  boiled  for  fifteen  minutes 
in  a  bath  containing  13  cc.  per  liter  of  a  4  percent  solution  of  caustic  soda, 
and  the  liquor  is  then  run  off  and  the  yarn  treated  with  an  equivalent 
amount  of  sulfuric  acid,  the  yarn  can  then  be  mordanted  with  the  use  of 
bichromates  and  be  finished  in  much  less  time  than  when  the  treatment 
with  caustic  soda  is  omitted;  also  the  wool  material  treated  with  caustic 
soda  is  softer  and  has  a  greater  affinity  for  dyestuffs  than  the  untreated 
wool. 

Burton  and  Barralet  ^  have  studied  the  action  of  sodimn  peroxide 
together  with  caustic  soda  on  wool.  Two  solutions  were  prepared,  the 
one  of  plain  caustic  soda  of  4|°  Tw.,  and  the  other  of  caustic  soda  and 
0.7  percent  of  sodium  peroxide;  glycerol  was  added  to  the  solutions. 
Two  samples  of  woolen  blanket  cloth  were  placed  in  each  solution,  and 
it  was  observed  that  in  a  few  minutes  the  piece  in  the  plain  caustic  soda 
solution  had  turned  to  a  yellowish  brown  color,  while  the  piece  in  the 
peroxide  bath  kept  its  original  color.  After  the  pieces  had  been  immersed 
for  one  hour  they  were  taken  out,  washed  with  water  and  soured  in  dilute 
sulfuric  acid.  The  piece  from  the  plain  caustic  soda  bath  lost  some  of  its 
brown  color  and  developed  a  strong  odor  of  hydrogen  sulfide.  The  other 
piece  improved  somewhat  in  color  and  gave  no  odor.  After  drying  it  was 
found  that  the  sample  from  the  peroxide  bath  showed  much  less  shrink- 
age than  the  other  and  when  dyed  with  Victoria  Blue  gave  a  bi'ight  blue 
color,  while  the  other  gave  only  a  dull  color. 

The  exact  nature  of  the  action  of  caustic  soda  under  the  conditions 
given  is  rather  difficult  to  satisfactorily  explain.  Through  a  microscopic 
examination  of  the  treated  fibers  it  appears  that  the  individual  scales 
on  the  surface  of  the  wool  are  more  or  less  fused  together  to  a  smooth 
surface,  which  would  account  for  the  great  increase  in  luster.  The 
additional  tensile  strength  is  prol^alily  accounted  for  by  the  same  fact, 
the  closer  adhesions  of  the  scales  giving  a  greater  rigidity  to  the  fiber. 
The  volatile  alkalies,  such  as  ammonia  and  ammonium  carbonate,  do 
not  have  any  marked  deleterious  effect  on  wool,  especially  at  low  tem- 
peratures; hence  these  compounds  form  excellent  scouring  materials. 
The  hydroxides  of  the  alkaline  earths,  though  less  violent  in  their  action 

>  Jour.  Soc.  Dyers  A  Col,  1910,  p.  24. 
2  Dyer  &  Calico  Printer,  1899. 


ACTION  OF  ALKALIES  ON  WOOL  157 

than  the  fixed  caustic  alkalies,  nevertheless  decompose  wool.  Milk  of 
lime,  even  in  the  cold,  abstracts  most  of  the  sulfur,  and  also  causes  the 
fiber  to  become  hard  and  brittle  if  the  action  is  prolonged ;  the  wool  also 
loses  its  felting  quality  to  a  considerable  extent.  Barium  hydroxide,  as 
previously  noted,  is  used  for  the  decomposition  of  wool  in  the  preparation 
of  lanuginic  acid.  Various  processes  for  the  treatment  of  wool  with 
caustic  alkalies  in  connection  with  glucose  have  been  patented,  as  follows : 
Cassella,  Fr.  Pat.  316,243,  dyeing  of  union  goods  with  sulfur  dyes;  Badi- 
sche,  Fr.  Pat.  28,696,  boiling-off  and  mercerising  cotton-silk  fabrics; 
Badische,  Ger.  Pats.  110,633;  117,249;  and  129,451  for  the  boiKng-off  of 
raw  silk  in  fabrics  containing  silk  and  cotton  or  wool.  See  also  Horace 
Koechlin,  Fdrb.  Zeit.,  1898,  p.  35,  for  the  use  of  caustic  soda  solutions  in 
the  printing  of  wool  to  obtain  two-color  effects.^ 

It  is  claimed  by  Karin  that  wool  may  be  protected  against  the  destruc- 
tive effect  of  alkalies  at  high  temperatures  by  a  treatment  with  formalde- 
hyde. 

According  to  Bethmann  ^  wool  which  has  been  treated  with  caustic 
soda  loses  its  reducing  properties;  for  instance,  wool  prepared  in  this 
manner  may  be  printed  a  good  Aniline  Black  with  the  usual  aniline 
padding  mixture  without  increasing  the  proportion  of  potassium  chlorate  ^ 
as  is  usually  the  case  on  ordinary  wool. 

Gelmo  and  Suida  state  that  alcoholic  caustic  potash  colors  wool  yellow 
while  at  the  same  time  materially  increasing  the  affinity  of  the  fiber  for 
substantive  dyes  in  a  neutral  bath. 

Schneider^  reports  the  rather  remarkable  observation  that  by  boiling 
wool  for  fifteen  minutes  with  a  bath  containing  13  cc.  of  normal  caustic 
soda  solution  per  liter,  and  rinsing  in  a  bath  containing  the  equivalent 
quantity  of  sulfuric  acid,  it  is  then  possible  to  mordant  the  wool  directly 
with  chrome  without  the  usual  addition  of  any  reducing  assistants  (such 
as  cream  of  tartar).  The  chroming  is  said  to  proceed  more  i-apidly  and 
the  mordanted  wool  dyes  better,  while  it  has  a  softer  feel  and  is  not  so 
sensitive  to  light  as  ordinary  chrome-mordanted  wool. 

Where  it  is  necessary  to  use  alkalies  in  the  treatment  of  wool, 
as  for  example,  in  neutralising  after  carbonising  with  acid,  caustic  alka- 
lies must  be  avoided,  and  only  ammonia  or  dilute  solutions  of  soda  ash 
used.  Even  the  latter,  however,  has  a  destructive  action  on  wool  if  used 
hot  (above  140°  F.)  or  if  used  in  concentrated  solutions.  Ammonia,  also, 
must  not  be  employed  too  strong  or  too  hot.  The  alkalies  having  the 
least   effect   on   wool,    perhaps,   are   ammonium   carbonate   and   borax. 

1  Also  see  Zeit.  Farh.  Ind.,  1902,  pp.  266  and  372. 

^Zeit.  angew.  Chem.,  1906,  p.  1817. 

3  Ger.  Pat.  170,228. 

*Jour.  Soc.  Dyers  &  Col.,  1910,  p.  24 


158  ACTION  OF  CHEMICAL  AGENTS  ON  WOOL 

Sodium  phosphate  is  also  a  mild  alkali  which  may  be  used  in  connection 
with  wool  without  fear  of  injury.  Potassium  carbonate  is  said  to  have  a 
less  injurious  effect  than  soda  ash,  and  on  this  account  is  still  quite  exten- 
sively used  in  wool  scouring  in  spite  of  its  higher  cost. 

Whenever  woolen  goods  are  treated  with  alkaline  solutions  of  what- 
ever character,  great  care  should  be  had  to  give  the  material  subsequently 
a  most  thorough  washing  in  order  to  remove  the  last  trace  of  alkali  as 
otherwise  after  drying  and  storing  alkali  spots  may  form,  resulting  in  a 
weakening  of  the  fiber  and  a  discoloration  of  the  goods.  Also  if  subse- 
quently dyed  the  pieces  may  exhibit  streaks  or  spots  due  to  the  action 
of  alkaline  residues  in  affecting  the  dyeing  properties  of  the  fiber. 

6.  Action  of  Reducing  Agents. — Reducing  agents  in  general  have  no 
action  on  the  wool  fiber  itself,  though  they  reduce  the  coloring  matter  in 
wool  and  consequently  are  useful  as  bleaching  agents.  Reducing  agents 
include  such  substances  as  sulfurous  acid,  sodium  bisulfite,  sodium  hydro- 
sulfite,  zinc  dust  with  acetic  acid,  stannous  chloride,  titanous  sulfate,  etc. 
They  act  in  a  manner  opposite  to  oxidising  agents  in  that  they  eliminate 
oxygen  from  the  substance  on  which  they  act.  The  action  of  a  boiling 
solution  of  sodium  bisulfite,  however,  is  remarkable,  though  it  is  not 
exactly  certain  in  this  case  whether  it  plays  the  part  of  a  reducing  agent 
or  an  acid  salt.  According  to  Elsasser  ^  a  sort  of  "  mercerisation  "  of  the 
fiber  takes  place  when  wool  is  boiled  with  a  concentrated  solution  of 
sodium  bisulfite.  The  fiber  acquires  a  soft,  gummy  character  and  shrinks 
considerably.  When  this  point  is  reached  the  material  is  then  stretched 
back  to  its  original  length  and  fixed  by  washing  in  cold  or  hot  water,  or  in 
solutions  of  such  substances  as  neutralise  bisulfite,  such  as  hypochlorite, 
etc.  The  strength  of  the  treated  wool  is  said  to  be  greater  than  the 
original,  while  the  fiber  acquires  a  high  degree  of  luster.  There  is  no 
record  as  yet,  however,  of  this  process  becoming  commercially  successful. 

7.  Action  of  Oxidising  Agents. — Toward  many  other  chemical  reagents 
wool  is  much  more  reactive  than  cotton,  and  either  absorbs  from  solution 
or  chemically  combines  with  many  substances.  The  fiber  is  quite  readily 
oxidised  when  treated  with  strong  oxidising  agents  such  as  potassium 
permanganate  or  bichromate,  becoming  greatly  deteriorated  in  its  qualities. 

Wlien  treated  with  solutions  of  hydrogen  peroxide  the  wool  fiber  be- 
comes bleached,  as  the  coloring  matter,  or  pigment,  is  destroyed.  Under 
ordinary  conditions  of  use,  solutions  of  hydrogen  peroxide  do  not  have  any 
deleterious  effect  on  the  qualities  of  the  wool  fiber  itself.  On  this  account 
this  reagent  is  largely  employed  for  the  bleaching  of  woolen  materials,  or 
materials  containing  mixed  cotton  and  woolen  yarns.  Instead  of  employ- 
ing a  solution  of  hydrogen  peroxide  itself,  sodium  peroxide  may  be  dis- 
solved in  acidulated  water  (with  sulfuric  acid),  giving  a  slightly  acid 

» Ger.  Pat.  233,210. 


ACTION   OF   CHLORINE  ON   WOOL  159 

solution  of  hydrogen  peroxide.  The  slight  excess  of  acid  is  used  for  the 
purpose  of  completely  neutralising  all  of  the  caustic  soda  that  is  formed 
when  sodium  peroxide  reacts  with  water,  as  the  presence  of  any  free  caustic 
soda  in  the  bleaching  bath  would  be  injurious  to  the  wool.  When  employed 
for  active  bleaching,  the  bath  is  usually  made  slightly  alkaline  by  the 
addition  of  ammonia,  silicate  of  soda,  borax,  or  sodium  phosphate. 

Dilute  solutions  of  potassium  permanganate  may  also  be  employed  for 
the  bleaching  of  wool.  The  solution  should  not  contain  more  than  2-3 
percent  of  potassium  permanganate  on  the  weight  of  the  wool,  and  the 
temperature  of  the  bath  should  not  be  over  120°  F.,  otherwise  there  is 
danger  of  damaging  the  fiber.  When  steeped  in  such  a  solution  of  potas- 
sium permanganate  the  wool  acquires  a  dark  brown  color  by  reason  of  the 
precipitation  of  a  hydrate  of  manganese  in  the  fiber.  Subsequent  treat- 
ment with  a  solution  of  oxalic  acid  or  of  sodium  bisulfite  removes  the 
manganese  compound,  leaving  the  fiber  clear  and  white.  This  is  a  very 
effective  method  of  bleaching  wool,  as  a  good  white  can  be  obtained  in  a 
short  space  of  time;  the  fiber,  however,  always  acquires  a  harsh  feel  and  a 
scroop,  owing  to  the  oxidising  action  of  the  permanganate  on  the  outer 
scales  of  the  fiber.     The  method  is  also  too  expensive  for  general  use. 

Kertesz  ^  has  made  some  interesting  tests  on  the  action  of  atmospheric 
agencies  on  wool  and  fabrics  made  therefrom.  He  states  that  exposure 
to  light  destroys  scoured  wool  most  rapidly,  dyed  wool  next,  and  wool 
treated  with  chromium  salts  least  rapidly.  The  use  of  chromium  salts 
for  improving  the  resistance  of  wool  is  the  subject  of  patent.^  Acid  salts, 
such  as  alum  and  iron  salts,  have  a  useful  effect,  but  are  inferior  to  chro- 
mium salts.  Fats  and  lanolin  proved  to  be  harmful  additions.  Prolonged 
action  of  ozone  weakens  wool,  but  the  fiber  remains  soft  and  elastic. 
Exposure  to  ultra-violent  light  gives  accelerated  changes  similar  to  those 
caused  by  weather  exposure.  The  biuret  reaction  is  useful  for  determining 
the  extent  of  injury  caused  by  weathering.  Wool  exposed  to  atmospheric 
agencies  becomes  acid  in  reaction  owing  to  the  sulfur  in  the  fiber  being 
oxidised  to  sulfuric  acid. 

8.  Action  of  Chlorine  on  Wool. — Toward  chlorine,  wool  acts  in  a 
peculiar  manner;  it  is  completely  decomposed  by  moist  chlorine  gas, 
but  in  weak  solutions  of  hj^pochlorites  it  absorbs  a  considerable  amount 
of  chlorine  and  is  strangely  altered  in  its  properties.  It  becomes  harsh, 
has  a  high  luster,  and  acquires  a  silklike  feel  or  "  scroop,"  at  the  same 
time  losing  its  felting  properties  though  its  attraction  for  coloring  matters 
in  general  is  largely  increased.  The  assertion  by  Witt  (Gespinstfasern, 
p.  9)  that  chlorinated  wool  is  soluble  in  ammonia  with  evolution  of  nitrogen 
is  denied  by  Grandmougin.^     The  action  of  chlorine  on  wool  was  first 

1  Fdrber  Zeitung,  vol.  30,  p.  137.  ^  Ger.  Pat.  286,340. 

3  Zeit.  Farh.  Ind.,  1906,  p.  399. 


160  ACTION  OF  CHEMICAL  AGENTS  ON  WOOL 

noticed  by  Mercer,  and  in  1865  Lightfoot  introduced  the  chlorination 
of  wool  into  practice  for  the  purpose  of  dyeing  aniline  black  on  wool. 
He  states  that  wool  is  worked  in  a  solution  of  bleaching  powder  for  twenty 
to  thirty  minutes,  and  then  passed  through  an  acid  bath.  For  the  prepara- 
tion of  the  bath  Lightfoot  used  2  ounces  of  bleaching  powder  per  gallon 
of  water,  and  this  he  states  is  sufficient  for  the  treatment  of  1  lb,  of  cloth. 
For  investigations  relating  to  the  chlorination  of  wool  see  Knecht  and 
Milnes,  Jour.  Soc.  Dijers  &  Col.,  1892,  p.  41;  Grandmougin,  Zeii.  Farb. 
Ind.,  1906,  p.  396;  Vignon  and  Mollard,  Jahres-Benchte,  1907,  p.  386; 
and  Pearson,  Jour.  Soc.  Dyers  &  Col.,  1909,  p.  81. 

Bromine  appears  to  have  a  similar  action  on  wool.  It  is  claimed  to  have 
the  advantages  over  chlorine  in  that  it  does  not  turn  the  material  yellow, 
and  that  in  mixtm'es  of  dyed  and  undyed  wool  the  former  is  not  attacked. 
This  latter  statement  is  open  to  doubt. 

By  the  chlorination  of  wool  is  meant  the  treatment  of  the  fiber  with  a 
solution  of  hypochlorite  in  such  a  manner  that  the  strength  and  other 
good  qualities  are  not  seriously  affected,  while  at  the  same  time  the  sub- 
stance of  the  fiber  appears  to  undergo  rather  remarkable  transformation, 
leading  to  a  considerable  alteration  in  its  chemical  properties.  Chlorinated 
wool  finds  quite  a  number  of  appHcations  in  practice.  The  process  is  used 
for  instance,  for  the  purpose  of  imparting  a  silklike  gloss  to  the  fiber.  The 
process  of  chlorination  is  employed  principally  in  the  printing  of  woolen 
fabrics  so  as  to  prepare  a  print  cloth  which  will  more  readily  take  the  dye- 
stuff.  It  is  also  used  to  a  considerable  extent  for  the  preparation  of  yarns, 
so  as  to  lessen  their  felting  qualities  and  at  the  same  time  increase  their 
dj^eing  properties. 

If  yarns  of  chlorinated  wool  and  ordinary  wool  are  woven  together  in 
pattern,  and  the  fabric  afterward  fulled,  since  the  chlorinated  wool  does 
not  felt  it  will  not  shrink  up  like  the  remainder  of  the  yarn,  and  in  con- 
sequence the  pattern  will  be  brought  out  with  very  good  effect;  a  great 
variety  of  novelties  may  be  produced  in  this  manner.  Finally,  the  property 
of  chlorinated  wool  to  dye  a  heavier  shade  than  ordinary  wool,  when  dyed 
in  the  same  bath,  is  also  utilised;  and  fabrics  with  beautiful  two-color 
effects  may  be  easily  obtained  in  this  manner  by  weaving  the  chlorinated 
wool  into  designs  with  ordinary  wool  and  afterward  dyeing  with  suitable 
coloring  matters.  A  slight  chlorination  is  also  given  to  woolen  cloth 
to  be  used  for  printing  so  it  will  take  the  colors  better;  see  also  Farbw. 
Hochst,  Fr.  Pat.  267,004. 

The  chlorination  of  the  woolen  yarn  is  carried  out  in  practice  as  follows: 
The  material  is  well  freed  from  all  greasy  matters  by  a  preliminary  scouring; 
this  must  be  very  thorough,  otherwise  good  results  will  not  be  obtained, 
as  the  yarn  is  liable  to  finish  up  very  unevenly.  A  steeping  in  hydrochloric 
acid  next  takes  place;   the  solution  should  be  cold  and  have  a  density  of 


ACTION  OF  CHLORINE  ON  WOOL  161 

1^"  Tw.  The  wool  should  be  left  in  this  bath  for  twenty  minutes.  It 
is  next  passed  into  a  solution  of  bleaching  powder  standing  at  3°  Tw.  and 
worked  for  ten  minutes,  after  which  it  is  again  treated  with  the  solution  of 
hydrochloric  acid  and  washed  thoroughly.^  It  is  said  that  sodium  hypo- 
chlorite is  better  to  use  than  chloride  of  lime,  and  sulfuric  acid  is  pref- 
erable to  hydrochloric,  showing  less  tendency  to  turn  the  material  yellow. 
The  yellow  color  due  to  the  chlorine  may  be  removed  by  treatment  with 
sulfurous  acid.- 

According  to  a  recent  German  patent,  the  harshness  of  chlorinated  wool 
may  be  considerably  lessened  by  working  the  material  first  in  a  solution  of 
a  salt  such  as  citrate  of  zinc  or  acetate  of  iron,  or  of  sodium  stannate  or 
aluminate;  this  is  followed  by  a  second  bath  of  very  dilute  alkali,  after 
which  the  goods  are  exposed  to  the  air.^  The  author,  however,  has  not 
been  able  to  obtain  any  satisfactory  results  on  testing  this  process. 

According  to  Pearson  the  following  is  the  chlorination  method  in  use 
for  the  manufacture  of  unshrinkable  woolen  underwear.  The  fabric  is 
treated  with  a  solution  of  sodium  hypochlorite  containing  not  more  than 
4.5  percent  of  available  chlorine.  After  each  addition  of  the  hypochlorite 
solution  the  liquid  is  acidified  with  hydrochloric  acid.  After  the  chlorine 
treatment  the  wool  is  thoroughly  rinsed,  and  then  treated  with  a  bath  of 
sodium  bisulfite  for  the  purpose  of  removing  excess  of  chlorine  from  the 
fiber  and  restoring  its  color.  A  final  washing  and  scouring  with  a  soap 
solution  containing  a  little  soda  ash  is  given.  Pearson  claims  that  chlo- 
rinated wool  may  be  distinguished  from  untreated  wool  by  allowing  a  drop 
of  water  to  fall  upon  it.  With  chlorinated  wool  the  drop  is  rapidly  ab- 
sorbed, forming  a  circular  spot;  whereas  vdth.  untreated  wool  the  drop  is 
slowly  absorbed  and  the  outHne  of  the  wetted  portion  is  irregular.  Also 
if  fabrics  of  the  treated  and  untreated  wool  be  rubbed  together  a  consider- 
able electric  charge  will  be  formed.  This  property  of  chlorinated  wool 
had  formed  the  basis  of  a  patented  "  electric  "  belt.  Garments  of  chlo- 
rinated wool,  however,  do  not  wear  weU,  and  are  rapidly  deteriorated  by 
laundering. 

The  chemical  action  of  the  chlorine  on  the  wool  is  evidently  that  of 
oxidation  rather  than  a  combination  of  the  fiber  ■^'ith  the  chlorine.  The 
increased  luster  and  the  loss  in  felting  properties  is  no  doubt  due  to  the 
partial  destruction  of  the  external  scales  on  the  surface,  or  rather  the 
softening  and  fusing  together  of  the  free  protruding  edges  of  these  scales. 
Microscopic  examination  seems  to  favor  this  opinion. 

iSee  Cassella,  Fr.  Pat.  279,381,  and  Ger.  Pat.  108,714.  See  also  Piatt,  Fdrber- 
Zeit.,  1898,  p.  3,  for  the  chlorination  of  wool  with  the  use  of  sulfuric  acid  and  chloride 
of  lime. 

2  See  Farbw.  Hochst,  Ger.  Pat.  95,719,  for  the  chlorination  of  wool  by  the  use 
of  chlorine  gas. 

3  See  Florin  and  Lagage-Roubaix,  Ger.  Pat.  123,097  and  123,098. 


162  ACTION  OF  CHEMICAL  AGENTS  ON  WOOL 

It  is  said  that  the  same  effects  produced  in  the  chlorination  of  wool 
can  be  obtained  by  the  use  of  potassium  permanganate  in  a  10  percent 
solution  acidified  with  sulfuric  acid.^  This,  however,  would  be  far  more 
expensive,  and  it  has  not  been  demonstrated  that  the  effects  are  equiv- 
alent. 

According  to  Lodge,-  when  chlorinated  wool  is  treated  with  potassium 
bichromate  for  mordanting  previous  to  dyeing,  the  fiber  is  much  deeper 
in  color  than  when  ordinary  wool  is  employed.  On  estimating  the  amount 
of  chrome  taken  up  by  the  fiber  in  each  case  it  was  found  that  when  using 
3  percent  of  potassium  bichromate  the  chlorinated  wool  took  up  2.29 
percent  and  the  ordinary  wool  only  1.16  percent. 

Knecht,  in  a  series  of  experiments  on  the  mordanting  of  wool  with 
chromium,  has  shown  that  chlorinated  wool  may  be  mordanted  with 
chrome  alum  without  any  decomposition  being  noticeable  in  the  bath. 
A  10-gram  sample  of  ordinary  wool  was  treated  with  600  cc.  of  water  and 
2  grams  of  sulfuric  acid,  then  well  squeezed  and  mordanted  with  10  percent 
of  chrome  alum,  and  in  this  case  no  decomposition  in  the  mordant  bath 
was  noticeable.  If,  after  the  treatment  with  acid,  the  wool  is  steeped 
for  a  quarter  of  an  hour  in  a  cold  dilute  solution  of  bleaching  powder,  then 
washed  and  mordanted  with  chrome  alum,  no  decomposition  of  the  chrome 
alum  occurs  in  the  bath,  but  there  is  observed  an  interesting  formation  of 
chromic  acid.  Apart  from  the  effect  of  the  oxidation  of  the  wool,  possibly 
the  good  results  obtained  on  chlorinated  wool  in  the  dyeing,  at  least  with 
certain  coloring  matters,  may  depend  to  some  extent,  according  to  Knecht, 
upon  the  acid  absorbed  by  the  wool.  In  the  case  of  the  above  test  the 
two  samples,  when  dyed  with  Alizarine,  have  a  garnet  red  color  on  the 
non-chlorinated  sample,  pointing  evidently  to  the  effect  of  the  acid  absorbed 
by  the  wool,  whereas  the  second  or  chlorinated  sample  gave  a  bluish  bor- 
deaux red  color,  due,  no  doubt,  to  the  presence  of  lime  in  the  wool. 

The  general  method  of  carrying  out  the  chlorinating  of  woolen  cloth 
is  as  follows :  A  solution  of  bleaching  powder  is  prepared  of  such  strength 
that  it  contains  from  4  to  5  percent  of  available  chlorine,  which  would 
correspond  to  a  solution  standing  at  about  17°  Tw.  A  solution  of  sodium 
carbonate  is  now  added  in  a  slight  excess  with  constant  stirring.  This 
will  cause  a  precipitation  of  the  lime  as  carbonate  of  lime,  and  on  allowing 
this  precipitate  or  sediment  to  settle,  the  clear  liquor  containing  sodium 
hypochlorite  in  solution  may  be  decanted.  The  solution  will  contain 
about  4  percent  of  available  chlorine,  and  should  have  a  specific  gravity 
of  about  1.1.  It  is  well  to  have  a  slight  excess  of  alkali  in  the  solution, 
so  that  the  subsequent  liberation  of  the  chlorine  may  take  place  gradually. 
Solutions  of  greater  strength  are  liable  to  form  chlorate  of  soda,  which 
has  a  bad  effect  on  the  wool,  in  that  it  tends  to  color  it  yellow. 

1  Kammerer,  Brit.  Pat.  5612  of  1907.  ^  jour.  Soc.  Dyers  &  Col,  1892,  p.  60. 


ACTION  OF  CHLORINE  ON  WOOL  163 

For  the  chlorination  proper  from  |  to  1  pint  of  this  sodium  hypochlorite 
solution  is  required  per  pound  of  wool.  Hydrochloric  acid  is  also  added  to 
the  solution  gradually  to  the  extent  of  about  the  volume  of  the  hypochlorite 
solution.  The  goods  are  run  through  this  liquor  and  then  well  rinsed. 
After  the  treatment  it  will  be  found  that  the  wool  has  acquired  a  somewhat 
yellowish  color.  This  may  be  removed  by  running  the  goods  through  a 
bath  containing  100  gals,  of  water,  1  gal.  sodium  bisulfite  liquor,  and 
1  pint  of  previously  diluted  sulfuric  acid.  In  place  of  the  bisulfite  treat- 
ment, a  bath  of  stannous  chloride  and  hydrochloric  acid  may  be  used. 
After  a  thorough  rinsing,  the  goods  are  finally  scoured  with  soap  to  which 
is  added  a  little  sodium  carbonate.  This  is  added  for  the  purpose  of 
softening  the  handle  or  feel  of  the  fiber. 

In  describing  the  chlorination  of  wool  most  experimenters  on  this  sub- 
ject have  insisted  that  a  prolonged  action  of  chlorine  on  wool  is  to  be 
avoided,  as  it  imparts  to  the  fiber  a  yellowish  color  and  a  harsh,  unpleasant 
feel.  It  is  also  generally  stated  that  a  chlorine  bath  which  has  once  been 
used  for  the  treatment  of  woolen  goods  can  be  again  strengthened  for 
further  use  by  the  addition  of  an  amount  of  hypochlorite  considerably 
less  than  the  original  quantity.  Bullard,i  however,  takes  exception  to 
these  statements.  He  points  out  that  while  the  chlorinating  of  cotton 
is  a  gradual  and  progressive  action,  the  reaction  with  wool,  however,  is  a 
very  rapid  one,  and  the  entire  amount  of  the  chlorine  is  absorbed  by  the 
wool  in  a  few  minutes;  consequently  the  strengthening  of  old  liquors  for 
further  use  is  quite  unnecessary. 

Bullard  made  experiments  showing  these  conclusions  by  using  a  piece 
of  woolen  fabric  weighing  20  grams  which  had  previously  been  subjected  to 
the  operations  of  soaping,  stoving,  washing,  etc.  A  solution  was  prepared 
containing  5  grams  of  sulfuric  acid  and  12  cc.  of  hypochlorite  of  soda 
(corresponding  to  0.6  gram  of  dry  bleaching  powder  of  good  quality) 
in  1  liter  of  water.  One  volume  of  such  a  solution  immediately  decolorises 
one  volume  of  a  solution  of  indigo  in  sulfuric  acid  so  diluted  that  its  color 
is  just  visible.  The  wool  is  steeped  in  the  chlorine  bath  for  one  minute,  and, 
after  removing  it,  the  bath  no  longer  decolorises  indigo  solution,  thus 
showing  that  all  of  the  chlorine  has  been  removed  by  the  wool.  Some- 
times, indeed,  half  a  minute  is  sufficient  for  the  removal  of  all  the  chlorine. 
A  further  addition  of  12  cc.  of  hypochlorite  solution  is  made  to  the  bath, 
and  the  wool  is  entered  again  for  a  minute.  On  testing  the  bath  it  will 
be  found  that  all  the  chlorine  has  again  been  abstracted.  This  may  be 
repeated  several  times,  provided  care  is  always  taken  that  an  excess  of 
acid  be  present.  After  three  or  four  of  such  operations  the  wool  acquires 
a  yellowish  tint  and  a  harsh  feel.  Even  when  the  hypochlorite  bath  is 
four  times  as  strong  as  that  given  above  (that  is  to  say,  equivalent  to 

1  Monit.  Sdent.,  1894. 


164  ACTION  OF  CHEMICAL  AGENTS   ON   WOOL 

12  percent  of  bleaching  powder  on  the  weight  of  the  wool)  evei-y  trace  of 
chlorine  will  have  been  removed  by  the  wool  in  a  treatment  of  two  minutes. 

From  this  it  is  to  be  seen  that  the  essential  point  for  consideration  in 
the  chlorination  of  wool  is  very  evidently  the  relative  proportion  of  chlorine 
and  wool  rather  than  the  time  of  action.  According  to  Bullard,  the  best 
proportion  is  from  2  to  5  percent  of  bleaching  powder  or  its  equivalent 
in  terms  of  sodium  hypochlorite  on  the  weight  of  the  wool  being  treated. 
If  calcium  hypochlorite  be  used,  the  acid  employed  must  be  hydrochloric, 
whereas  with  the  use  of  sodium  hypochlorite  either  hydrochloric  or  sulfuric 
acid  may  be  employed;  but  in  any  case,  an  excess  of  acid  should  always  be 
present  in  the  solution.  As  hydrochloric  acid  tends  to  render  the  wool 
yellow  when  used  in  this  connection,  the  employment  of  sodium  hypo- 
chlorite with  sulfuric  acid  is  to  be  preferred.  The  acid  bath  may  precede 
or  follow  the  chlorine  bath.  Preferably  the  former  method  of  treatment 
is  to  be  used.  The  amount  of  acid  is  of  secondary  importance,  as  it  is 
only  necessary  that  an  excess  should  be  used.  An  important  point  in  the 
chlorination  of  wool  is  that  of  bringing  as  soon  as  possible  the  entire  bulk  of 
the  wool  under  treatment  into  contact  with  the  liberated  chlorine.  Wlien 
treated  on  the  jigger  or  over  a  winch  there  is  great  danger  of  the  pieces 
being  ''  ended  "  owing  to  the  rapid  absorption  of  the  chlorine.  In  using 
chloride  of  lime  for  the  chlorination  it  is  necessary  to  avoid  the  use  of 
sulfuric  acid,  as  the  insoluble  calcium  sulfate  that  is  formed  adheres 
tenaciously  to  the  wool.  With  hypochlorite  of  soda  either  sulfuric  or 
hydrochloric  acid  may  be  added. 

A  mechanical  difficulty  which  has  to  be  overcome  is  that  of  obtaining 
as  even  as  possible  an  absorption  of  chlorine  by  the  fiber.  If  treated  in 
the  chain-form,  those  portions  of  the  material  reaching  the  liquor  first  ab- 
sorb too  much  chlorine,  while  the  latter  portions  receive  little  or  none. 
It  is  better,  therefore,  in  the  treatment  of  cloth  to  carry  out  the  operation 
in  open  width,  making  use  of  a  frame  similar  to  that  employed  for  the 
dyeing  of  cloth  in  the  open  width  in  indigo  vats.  However,  the  parts 
of  the  frame  must  be  constructed  of  some  material  capable  of  resisting 
the  prolonged  action  of  hypochlorite  solutions.  The  rapid  removal 
of  the  chlorine  from  the  hypochlorite  bath  might  have  been  attributed 
to  the  action  of  the  sulfuric  acid  present  in  the  stoved  wool,  but  this 
conclusion  was  shown  to  be  wrong  by  the  results  of  an  experiment  carried 
out  with  a  piece  of  woolen  cloth  which  had  been  stoved  but  not  subse- 
quently washed.  This  piece  was  steeped  in  the  acid  bath,  and  then  in 
the  sodium  hypochlorite  liquor,  and  finally  in  a  second  bath  containing 
sulfuric  acid.  In  this  last  bath  a  considcral)lc  evolution  of  sulfur  dioxide 
took  place,  but  on  washing,  the  wool  was  found  to  be  satisfactorily  chlo- 
rinated. Evidently  the  sulfuric  acid  and  hypochlorite  reacted  to  produce 
chlorine,  and  a  certain  amount  of  the  liberated  soda  combined  with  the 


ACTION  OF  CHLORINE  ON  WOOL  165 

sulfui'ous  acid  to  form  sodium  sulfide,  this  being  decomposed  in  a  second 
bath  with  hberation  of  sulfur  dioxide.  The  satisfactory  result  of  the 
chlorination  indicates  that  in  the  presence  of  wool  and  sulfurous  acid 
chlorine  is  more  readily  absorbed  by  the  fiber  than  neutralised  and  ren- 
dered inactive  by  the  sulfurous  acid. 

Trotman  ^  points  out  that  some  of  the  properties  that  are  usually 
attributed  to  chlorinated  wool  relate  only  to  wool  which  has  been  improp- 
erly treated  with  the  result  of  more  or  less  breakdown  in  the  fiber.  The 
increased  affinity  of  dyes,  for  example,  is  a  property  to  be  found  only  in 
wool  that  has  been  chlorinated  overmuch;  whereas  properly  treated  fibci 
will  not  show  such  a  property.  The  wetting  power  of  properly  chlorinated 
wool  is  also  not  much  greater  than  that  of  ordinary  wool.  The  change  in 
properties  has  been  shown  to  be  due  to  damaged  fibers.  Trotman  thinks 
that  the  customary  methods  of  chlorination  are  too  indefinite  in  the  control 
of  the  conditions,  particularly  with  regard  to  strength  and  amount  of 
chlorine  reacting  with  the  fiber.  Trotman  comes  to  the  conclusion  that 
wool  is  more  easily  damaged  by  chlorine  than  by  hypochlorous  acid; 
hence  bleaching-powder  solution  should  be  used  under  conditions  that 
minimise  the  quantity  of  chlorine  present.  When  using  bleaching- 
powder  solution  and  a  mineral  acid  it  is  rarely  safe  to  exceed  the  strength 
of  0.6  gm.  of  available  chlorine  per  liter.  The  practice  of  soaking  in  the 
acid  is  dangerous,  unless  the  quantity  of  acid  is  carefully  controlled,  since 
the  excess  of  acid  carried  over  into  the  bleach  liquor  causes  evolution  of 
chlorine.  Excess  of  hypochlorous  acid  or  of  chlorine  causes  destruction 
of  both  epithelial  scales  and  cortical  scales  and  gives  bad  wearing  qualities 
to  the  fiber.  Instead  of  using  hydrochloric  acid,  as  is  generally  done, 
Trotman  recommends  the  use  of  boric  acid  as  giving  a  suitable  chlorination 
without  injury  to  the  fiber. 

The  lustering  of  wool  by  chlorination  finds  a  rather  extensive  applica- 
tion in  the  lustering  of  oriental  rugs.  These  rugs  after  importation 
into  this  country  are  generally  ''  washed  "  by  treating  with  a  solution  of 
chloride  of  lime.  This  solution  is  usually  just  swabbed  on  the  surface  of 
the  spread-out  rugs  and  serves  the  purpose  of  both  lustering  the  fiber  and 
also  of  dulfing  the  colors  somewhat,  so  as  to  give  the  rugs  an  "  antique  " 
appearance.  The  natives  in  India  and  Persia  dye  the  rugs  in  rather 
bright  colors  and  when  first  imported  the  rugs  have  an  appearance  of 
newness  about  them  which  is  not  attractive  to  the  trade.  As  the  treat- 
ment with  chloride  of  lime  is  rather  crudely  done  and  frequently  the 
excess  of  bleach  is  not  removed  from  the  rug  by  proper  washing,  the 
method  of  treatment  often  leads  to  very  disastrous  results  as  far  as  the 
durability  of  the  rug  is  concerned.  A  treatment  with  a  strong  solution 
of  caustic  soda  is  also  frequently  given  the  rugs  for  the  purpose  of  lustering 
1  Jour.  Soc.  Chem.  Ind.,  1922,  p.  219. 


166  ACTION  OF  CHEMICAL  AGENTS  ON  WOOL 

the  fiber.     It  has  already  been  pointed  out  that  such  a  treatment  has  this 
effect  on  the  wool  fiber.     But  here  again  the  process  should  be  very  care- 
fully done  in  order  to  avoid  injury  to  the  fiber.     Another  method  of 
lustering  rugs  is  recommended,  as  follows: 
A  preparation  is  made  up  of 

16  gallons  of  water 
66  lbs.  best  white  soap 

4  quarts  olive  oil 

4  quarts  cocoanut  oil 
12  quarts  cottonseed  oil 

4  quarts  borax 

The  preparation  is  placed  in  a  vessel  and  boiled,  and  then  mixed  with 
cold  water  in  the  proportion  of  1  quart  of  the  mixture  to  7  quarts  of  water. 
This  fluid  may  then  be  sprayed  on  to  the  fabric  to  be  treated,  during 
the  last  few  rounds  of  straightening  in  the  gig  or  raising  machine. 

W.  H.  Schweitzer  ^  describes  a  process  for  the  chlorination  of  wool  in 
connection  with  other  processes  for  the  production  of  waterproof  fabrics  as 
follows:  Fifty  kilos,  of  a  fine  wool  cloth  are  treated  at  ordinary  tempera- 
ture with  a  filtered  solution  of  40  kilos,  of  chloride  of  lime  in  1500  liters 
of  water  to  which  an  equivalent  quantity  of  hydrochloric  acid  has  been 
previously  added,  until  the  developed  hypochlorous  acid  disappears,  which  is 
generally  the  case  after  half  an  hour.  The  cloth  is  then  abundantly  rinsed 
with  cold  water.  Afterward  it  is  bleached  by  dipping  it  into  a  solution 
of  sodium  hydrosulfite  or  of  sulfurous  acid  and  rinsed.  Then  the  bleached 
fiber  is  boiled  in  a  solution  of  3  kilos,  of  wax  soap  in  1500  liters  of  water 
and  rinsed  in  cold  water.  The  wax  soap  employed  is  prepared  by  saponify- 
ing 3  parts  of  beeswax  with  3  parts  of  solid  soda  lye.  The  cloth  is  then 
treated  for  a  relatively  short  time,  varying  from  a  few  minutes  to  one- 
quarter  of  an  hour,  according  to  the  thickness  of  the  fiber  or  other  reasons, 
with  a  solution  of  15  kilos,  of  solid  soda  lye  in  1500  liters  of  water,  wrung 
out  and  again  copiously  rinsed  with  water.  Finally  the  cloth  is  boiled  in  a 
solution  of  Castile  soap,  to  which  at  the  end  some  acetic  acid  has  been 
added,  dried  and  calendered. 

9.  Action  of  Formaldehyde  on  Wool. — When  wool  is  treated  with  a 
4  percent  solution  of  formaldehyde  it  is  made  much  more  resistant  to 
alkalies  and  also  shows  a  decreased  affinity  toward  dyestuffs.  Kann 
has  described  this  use  of  formaldehyde  as  a  means  of  dyeing  wool  with 
vat  dyes  in  which  a  strongly  alkaline  bath  is  employed.  The  formaldehyde 
may  be  added  directly  to  the  alkaline  bath.  It  is  also  claimed  that  sulfur 
dyes  may  be  applied  to  wool  in  the  same  manner.  Wool  treated  with 
formaldehyde  is  said  to  be  much  more  resistant  to  the  action  of  steaming 
than  untreated  wool.    There  have  been  many  attempts  to  devise  a  method 

1  U.  S.  Patent  1,389,274. 


ACTION   OF   FORMALDEHYDE   ON   WOOL  167 

of  treatment  whereby  the  wool  fibers  could  be  protected  from  the  destruc- 
tive action  of  the  alkali  which  is  required  in  dye  baths  employed  for  these 
colors.     Kann  has  taken  out  a  number  of  patents  during  the  last  few 
years  describing  the  use  of  formaldehyde  for  this  purpose.     It  was  first 
recommended  to  employ  a  4  percent  solution  of  formaldehyde  for  the 
treatment  of  the  wool,  but  it  is  now  pointed  out  that  the  use  of  such  a 
solution,  although  protecting  the  wool  to  a  considerable  degree  against 
action  of  the  alkali,  decreases  greatly  its  affinity  for  dyestuffs.     In  later 
patents  formaldehyde  was  added  to  the  alkaline  dye  bath,  and  it  was 
eventually  discovered  that  only  small  quantities  of  formaldehyde  are 
necessary  to  produce  the  desired  effect.     When  used  in  these  proportions 
the  formaldehyde  does  not  decrease  the  affinity  of  the  wool  fiber  for  dye- 
stuffs.     It  is  only  necessary  to  use  an  amount  of  commercial  formaldehyde 
equivalent  to  |  to  iV  of  1  percent  of  the  weight  of  the  bath  used  to  produce 
the  desired  effect.     For  example,  about  3  ozs.  of  commercial  formaldehyde 
per  10  gallons  of  water  is  all  that  is  necessary.     In  cases  where  the  wool 
is  to  be  treated  with  formaldehyde  before  its  immersion  in  the  dye  bath, 
it  is  necessary  to  make  the  formaldehyde  solution  slightly  acid  by  the 
addition  of  a  small  quantity  of  sodium  carbonate.     If  formaldehyde  is 
added  directly  to  the  dye  bath,  it  should  be  allowed  to  act  slowly  by 
maintaining  the  bath  at  a  comparatively  low  temperature  for  several  min- 
utes.    It  has  previously  been  considered  that  the  action  of  formaldehyde 
was  a  catalytic  one,  but  when  the  treated  wool  is  moistened  with  hydro- 
chloric acid  and  heated,  formaldehyde  is  liberated  in  a  sufficient  quantity 
to  render  it  evident  that  a  chemical  composition  has  occurred  between 
the  substance  of  the  wool  fiber  and  the  formaldehyde  itself.     By  use  of 
formaldehyde  treatment  of  wool  it  has  been  found  possible  to  dye  this 
fiber  with  various  sulfur  colors  in  the  dye  bath  in  which  a  considerable 
quantity  of  the  strong  alkali  sodium  sulfide  is  necessarily  present  to 
maintain  the  solution  of  the  dyestuff.     This  same  treatment  can  also  be 
employed  on  woolen  material  which  is  subsequently  subjected  to  the 
action  of  steaming,  and  thereby  the  deleterious  effect  on  the  fiber  of  the 
steaming  operation  is  said  to  be  reduced  by  80  percent.     Furthermore, 
raw  wool  which  has  been  treated  with  formaldehyde  may  be  scoured  with 
a  solution  containing  -^  percent  of  caustic  potash  and  a  little  soap  without 
any  special  detrimental  action  on  the  fiber.     This  process  of  treatment 
is  also  available  for  use  with  goods  made  up  of  cotton  and  woolen  mixtures. 
It  is  possible  that  the  action  of  formaldehyde  on  wool  is  to  be  explained 
by  a  condensation  of  the  formaldehyde  with  the  amino  group  in  the  sub- 
stance of  the  wool  fiber.     It  is  furthermore  stated  that  wool  which  has 
been  treated  by  the  formaldehyde  method  is  not  seriously  affected  by 
immersion  for  twenty  minutes  in  a  20  percent  solution  of  sodium  carbonate 
somewhat  below  the  boiling  point.     At  a  temperature  of  160°  F.  the 


168  ACTION  OF  CHEMICAL  AGENTS  ON   WOOL 

wool  is  not  affected  by  even  ^  percent  solutions  of  caustic  alkali,  and  it  is 
also  unaffected  by  treatment  with  boiling  water. 

For  the  preservation  of  wool  against  the  action  of  alkaline  solution 
also  see  reference  to  Protectol  or  the  sodium  salt  of  lignin  sulfonate  pre- 
pared from  sulfite  pulp  waste  liquors. 

10.  Action  of  Metallic  Salts;  Mordants. — With  neutral  metallic  salts 
wool  does  not  seem  very  reactive,  as  it  does  not  absorb  them  appreciably 
from  their  solutions.  Neutral  salts  of  the  alkali  or  alkaline-earth  metals, 
such  as  common  salt,  glaubersalt,  potassium  chloride,  magnesium  sul- 
fate, etc.,  have  no  action  on  wool.  Even  in  boiling  solutions  the  fiber 
hardly  absorbs  the  slightest  trace.  Toward  certain  salts,  however, 
wool  acts  as  a  reducing  agent;  this  being  the  case  with  potassium  nitrate 
which  is  reduced  to  potassium  nitrite.^  With  salts  of  the  heavy  metals, 
however,  and  more  particularly  those  of  aluminium,  iron,  chromium, 
copper  and  tin,  wool  is  very  reactive;  the  salts  include  the  sulfates, 
chlorides,  nitrates,  acetates,  formates,  oxalates,  tartrates,  etc.  When 
boiled  with  these  solutions  the  substance  of  the  wool  combines  with  the 
basic  salt  or  with  the  metallic  hydroxide  though  in  just  what  manner 
is  not  yet  accurately  determined. - 

From  experiments  of  Bland  and  Fort^  it  would  seem  that  solutions 
of  glaubersalt  (as  an  example  of  a  neutral  salt  solution)  have  a  slight 
dissolving  action  on  the  substance  of  the  wool  fiber.  By  treating  5  grams 
of  wool  with  a  solution  of  1  gram  of  glaubersalt  in  150  cc.  of  water  at  the 
boil  for  three  hours,  there  was  a  loss  of  wool  substance  amounting  to 
0.5  percent  on  the  weight  of  the  fiber.  A  similar  test  with  pure  silk  gave 
a  loss  of  0.6  percent. 

With  salts,  which  are  acid  in  reaction  and  are  capable  of  being  easily 
dissociated,  such  as  alum,  ferrous  sulfate,  potassium  bichromate,  etc., 
the  wool  fiber  possesses  considerable  attraction,  especially  when  boiled 
in  their  solutions.  On  this  reaction,  in  fact,  are  based  the  important 
methods  of  mordanting  wool  with  various  metallic  salts  as  a  previous 
preparation  for  the  dyeing  of  many  coloring  matters. 

According  to  Gelmo  and  Suida  ^  when  wool  is  boiled  for  one  hour  in  a 
solution  of  alum  acidified  with  sulfuric  acid,  a  considerable  hydrolysis  is 
caused,  there  being  considerable  loss  in  weight,  and  the  formation  of  soluble 
amino  acids.  Some  of  the  decomposition  products  resemble  peptones 
in  their  action.  Wool  treated  with  a  0.1  percent  solution  of  alcoholic 
zinc  chloride  and  washed  shows  a  decidedly  decreased  affinity  for  basic 
dyes  and  a  greater  affinity  for  acid  dyes. 

'  See  Schwalbe,  Fdrbetheorien,  p.  58. 

^  For  the  action  of  salts  of  organic  bases  on  wool,  see  Schwalbe  Fdrbetheorien, 
p.  158. 

5  Jmir.  Soc.  Dyers  &  Col,  1915,  p.  178. 

*  Monatsch.  f.  Chemie,  vol.  26,  p.  855. 


ACTION  OF  METALLIC  SALTS;    MORDANTS 


169 


Schellens  ^  has  furnished  some  interesting  experiments  showing  the 
relative  power  of  fixation  of  metalhc  salts  possessed  by  various  textile 
fibers.  With  solutions  of  ferric  chloride,  for  instance,  the  following 
results  were  obtained: 


Cotton-wool.  . 
Filter-paper. . 
Vegetable  silk 

Jute 

Raw  silk .... 
Wool 


Solution  No.  1 

Containing 

1  Percent  of  Iron. 


0.112 

0.23 

1.01 

0.56 

0.67 

0.84 


Solution  No.  2 

Containing 

0.1  Percent  of  Iron. 


0.112 

0.123 

0.56 

0.44 

0.67 

0.36 


The  figures  refer  to  the  weight  of  iron  fixed  by  1  gram  of  the  fiber  from 
50  cc.  of  the  respective  solutions. 

The  metallic  salt  chiefly  employed  for  the  mordanting  of  wool  is 
potassium  bichromate  though  of  late  years  sodium  bichromate  has  largely 
replaced  the  potassium  salt.  The  sodium  salt  is  less  costly,  but  has  the 
disadvantage  of  absorbing  moisture  from  the  air,  and  therefore  unless 
carefully  stored  its  strength  is  liable  to  change.  When  properly  handled, 
however,  sodium  bichromate  gives  as  good  results  as  those  obtained  with 
the  potassium  compound.  The  following  table  gives  the  solubility  of  the 
two  salts  in  100  parts  of  water: 

32°  F.        176°  F.      212°  F. 

Potassium  bichromate 5  73  102 

Sodium  bichromate 107  143  163 

If  wool  is  simply  boiled  in  a  dilute  solution  of  potassium  bichromate, 
the  fiber  will  take  up  from  solution  a  considerable  portion  of  the  chromium 
compound,  presumably  in  the  form  of  a  chromate  of  chromium;  that  is 
to  say,  a  combination  of  chromic  acid  with  chromic  oxide.  The  sub- 
stance of  the  wool  fiber  itself  apparently  has  a  reducing  action  on  the 
potassium  bichromate.  It  has  been  found  that  this  action  is  promoted 
and  accelerated  by  the  presence  of  acids  and  certain  organic  compounds 
(such  as  tartar).  Therefore  it  is  customary  to  add  such  compounds  to 
the  mordanting  bath.  Sulfuric  acid,  tartar,  lactic  and  formic  acids  are 
chiefly  used  for  this  purpose.     It  has  already  been  pointed  out  that  wool 


1  Arch.  Pharm.,  1905,  p.  617. 


170  ACTION  OF  CHEMICAL  AGENTS  ON  WOOL 

is  capable  of  combining  with  acids  (probably  due  to  its  basic  nature);  a 
similar  reaction  seems  to  take  place  when  wool  is  boiled  with  tartar 
(potassium  acid  tartrate),  the  fiber  combining  with  the  tartaric  acid  and 
leaving  normal  tartrate  in  the  bath.  The  same  is  also  true  with  ammo- 
nium sulfate,  the  wool  combining  with  the  sulfuric  acid  and  setting  free 
ammonia. 

The  following  table  gives  the  equivalent  amounts  of  various  assistants 
to  use  with  3  percent  of  chrome  ^  in  mordanting: 

Percent. 

Tartar 2.5 

Lactic  acid 3.0 

Oxalic  acid 2.0 

Formic  acid 1.5 

Sulfuric  acid 1.5 

Tartar  is  said  to  give  shades  of  a  better  "  })loom  "  than  any  of  the  other 
assistants.  Lactic  acid  does  not  have  as  good  leading  properties,  but 
gives  colors  somewhat  faster  than  those  given  with  tartar.  Oxalic, 
formic,  and  sulfuric  acids  exhaust  the  mordanting  bath  more  completely 
and  give  the  mordanted  material  the  appearance  of  having  more  chrome 
on  it,  but  they  do  not  produce  as  good  shades,  and  a  slight  excess  of  any 
of  these  three  acids  is  lial)le  to  furnish  poor  colors. 

When  wool  is  mordanted  with  potassium  bichromate  and  sulfuric 
acid,  compounds  of  chromic  acid  and  chromium  oxide  of  a  more  or  less 
yellowish  color  are  fixed  in  the  fiber.  By  increasing  the  proportion  of 
sulfuric  acid  the  mordant  has  a  greener  shade  and  is  richer  in  chromic 
oxide.  According  to  Ulrich  ^  the  reduction  of  the  chromic  acid  is  brought 
about  by  the  products  formed  by  the  gradual  hydrolysis  of  the  fiber 
substance  by  the  acid.  When  lactic  and  formic  acids  are  employed  in 
place  of  sulfuric  acid,  they  simply  accelerate  the  reduction.  Experiments 
on  the  action  of  formic  acid  on  chromic  acid  have  shown  that  a  fairly  high 
reaction  velocity  is  reached  only  with  very  high  concentrations  of  the 
formic  acid,  for  even  with  500  molecules  of  formic  acid  per  molecule  of 
chromic  acid,  the  reduction  is  not  complete  after  boiling  for  one  hour. 
Experiments  in  the  presence  of  wool  have  shown  that  the  formic  acid 
has  little  influence  on  the  reduction  process,  the  conversion  of  the  chromic 
acid  into  chromic  oxide  being  caused,  even  in  its  presence,  by  the  products 
formed  by  the  hydrolysis  of  the  fiber.  The  part  taken  by  the  formic  acid 
in  the  mordanting  of  wool,  therefore,  is  simply  to  accelerate  the  absorption 
of  the  chromium  compounds  by  the  fiber. 

1  The  term  "chrome"  in  dyehouse  parlance  is  a  general  term  for  either  potassium 
or  sodium  bichromate. 

2  Zeit.  physiol.  Chetn.,  1908,  p.  25. 


COMPARISON  OF  VARIOUS   MORDANTS 


171 


11.  Comparison  of  Various  Mordants. — Grandmougin  ^  has  deter- 
mined the  power  of  mordanting  wool  possessed  by  salts  of  the  following 
elements : 


Copper 

Boron 

Lead 

Tellurium 

Silver 

Aluminium 

Thorium 

Tungsten 

Gold 

Ytterbium 

Vanadium 

Uranium 

Beryllium 

Lanthanum 

Arsenic 

Chlorine 

Magnesium 

Thalium 

Antimony 

Manganese 

Calcium 

Silicon 

Didymium 

Bromine 

Zinc 

Titanium 

Bismuth 

Iodine 

Strontium 

Zirconium 

Sulfur 

Iron 

Cadmium 

Tin 

Chromium 

Cobalt 

Barium 

Cerium 

Selenium 

Nickel 

Mercury 

Erbium 

Molybdenum 

Platinum 

The  mordants  employed  were  for  the  most  part  either  the  sulfate,  nitrate, 
chloride  or  acetate  of  the  metal,  together  with  some  assistant  such  as 
tartar,  oxalic  acid,  or  acetic  acid.  The  mordanted  wool  proved  to  be 
white,  gray,  or  pale  yellow  in  color  except  with  the  copper  and  also  in  the 
following  cases:  Selenium  dioxide  with  sodium  bisulfite  gave  a  brownish 
red  color.  Ammonium  molybdate  with  hydrochloric  acid  and  sodium 
bisulfite  gave  a  pale  blue  color.  Tellurium  dioxide  and  sodium  bisulfite 
gave  a  brownish  black  color.  The  mordanted  patterns  were  dyed  with 
various  coloring  matters  as  shown  in  the  following  table,  and  each  pattern 
was  divided  into  four  portions,  of  which  the  first  was  merely  washed 
with  water,  the  second  soaped  at  60°  C,  the  third  exposed  to  the  action 
of  light,  and  the  fourth  tested  for  fastness  to  fulling.  The  results  were 
classified  according  to  the  depth  of  color  and  the  fastness.  Class  5  com- 
prising the  deepest  and  fastest  colors,  Classes  4  and  3  being  inferior  in 
depth  and  fastness.  Class  2  including  the  indifferent  colors  which  were  no 
deeper  in  color  than  those  obtained  on  unmordanted  wool  and  were  easily 
removed  by  soaping,  while  in  Classes  1  and  0  the  results  were  negative, 
as  these  mordants  serve  as  resists  to  the  dyestuffs.  Grandmougin  does 
not  consider  it  possible  to  establish  any  connection  between  the  mordanting 
power  of  an  element  and  its  position  in  the  periodic  system.  The  compara- 
tive value  of  the  elements  as  mordants  may  be  expressed  as  follows; 
Useful  mordants — Chromium,  Uranium, — Titanium,  Mercury,  Thorium, 
Bismuth,  Iron, — Aluminium,  Copper,  Tin, — Tungsten,  Vanadium,  Zir- 
conium. Lead, — Lanthanum,  Cerium,  Ytterbium,  Antimony, — Cadmium, 
Didymium,  Cobalt,  Nickel,  Arsenic.  Indifferent  mordants — Beryllium, 
Magnesium,  Calcium,  Zinc,  Strontium,  Barium,  Boron,  Thallium,  Man- 
ganese. Negative  mordants  (useful  as  resists) — Molybdenum,  Platinum, 
Silver,  Silicon,  Erbium,  Chlorine,  Bromine,  Iodine,  Gold,  Sulfur,  Selenium, 
Tellm"ium. 

1  Bull.  Soc.  Ind.  Mulh.,  1898. 


172 


ACTION   OF   CHEMICAL  AGENTS   ON   WOOL 


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WEIGHTING   OF  WOOLEN  FABRICS 


173 


The  action  of  tungstic  acid  and  sodium  metatimgstate  on  wool  has  been 
investigated  by  Schoen.^  It  was  found  that  wool  which  has  been  boiled 
with  a  solution  of  sodium  tungstate  has  very  little  affinity  for  the  acid 
dyes,  whereas  it  will  dye  heavier  colors  with  the  basic  dyes.  The  treat- 
ment with  the  sodium  tungstate,  therefore,  has  probably  neutralised  the 
basic  functions  and  strengthened  the  acid  functions  of  the  wool.  Tungstic 
acid  2  may  be  used  to  permanently  protect  woolens,  furs,  and  hair  from 
moths.  The  material  is  immersed  in  a  3  percent  solution  of  colloidal 
tungstic  acid  to  which  sodium  sulfate  and  sulfuric  acid  are  added.  The 
treatment  may  be  applied  before,  during,  or  after  dyeing. 


Fig.  76. — Machine  for  Weighting  Wool  Piece  Goods. 


12.  Weighting  Woolen  Fabrics. — Certain  metallic  salts  are  used  with 
wool  for  the  purpose  of  giving  increased  weight  to  the  fabric.  Magnesium 
chloride  is  a  most  useful  loading  agent  on  account  of  its  possessing  great 
hygroscopic  properties.  The  action  which  takes  place  when  a  wool  cloth 
is  passed  through  a  solution  containing  magnesium  chloride  is  that  the 
cloth  will  absorb  the  chloride,  which  is  permanently  retained  in  the  fabric 
in  liquid  form.  Zinc  chloride  possesses  similar  properties  to  those  of 
magnesium  chloride.  To  a  limited  degree  magnesium  sulfate  is  employed 
as  a  loading  agent.  When  this  agent  is  absorbed — especially  to  a  large 
degree — a  white  powder  is  deposited  on  the  fiber  of  the  fabric,  which  is 
more  or  less  discernible.  Glaubersalt,  which  is  employed  as  a  leveling 
agent  during  acid  dyeing,  may  also  be  stated  to  be  a  loading  agent.     The 

^Bull.  Soc.  Iml.  Mulh.,  1892. 

2  According  to  Bayer,  Brit.  Pat.  173,536. 


174 


ACTION  OF  CHEMICAL  AGENTS  ON  WOOL 


action  of  this  salt  is  to  deposit  a  precipitate  on  the  fibers  that  constitute 
the  fabric,  which  action  results  in  increased  weight.  The  amount  of 
loading  agent  employed  in  the  solution  is  controlled  by  the  increased 
weight  required. 

The  process  of  weighting  is  usually  carried  out  after  the  scouring,  dyeing, 
raising,  cutting,  and  brushing  processes.  During  the  process  of  loading 
slight  shrinkage  has  been  developed;  also,  the  cloth  is  in  a  wet  condition, 
and  in  consequence  drying  and  tentering  must  be  subsequent  operations. 
Figure  76  illustrates  the  type  of  machine  employed  for  imparting  weight 
to  a  fabric. 

To  illustrate  the  influence  of  the  different  loading  agents,  and  also  the 
effect  of  different  quantities  of  these  agents,  the  following  tests  have  been 
carried  out  by  E.  Midgley  (Textile  Manufacture!').  The  cloth  employed 
in  every  case  was  of  a  whipcord  character. 

INFLUENCE  OF  LOADING 


E 
oZ 

U 

Remarks. 

Weight 

per 
Yard. 

Amount 

of 
Moisture 
Con- 
tained. 

Warp. 

Filling. 

Mean. 

strength. 

Elas- 
ticity. 

Strength. 

Elas- 
ticity. 

Strength. 

Elas- 
ticity. 

1 
2 
3 
3a 

4 
4a 

Unadulterated 

Magnesium  chloride .... 

Magnesium  sulfate 

As  3,  but  washed  in  cold 

water 

Magnesium  sulfate 

As  4,  but  washed  in  cold 

water 

Oz. 
15| 

181 
221 

n\ 

171 
20  i 

17J 

Percent. 
14 
22 
45 
17 

15 
24 

16 

Kilos. 
53.5 
45.9 
42.0 
52.6 

49.0 
50.87 

48.75 

Cm. 

4.25 

7.1 

7.75 

5.15 

6.05 
4.45 

5.5 

Kilos. 
46.5 
35.1 
37.5 
48.0 

46.75 
47.2 

44 .  25 

Cm. 

4,62 

7.17 

8.4 

6.1 

6.2 
6.27 

5.8 

Kilos. 
50.0 
40.5 
39.7 
50.0 

47.8 
49.0 

46.5 

Cm. 
4.4 

7.1 
8.0 
5.6 

6.1 
5.3 

5.6 

Wool  is  sometimes  weighted  surreptitiously  with  magnesium  chloride. 
Cases  have  been  reported  where  woolen  yarns  were  habitually  weighted 
7.5  percent  by  incorporating  with  the  yarn  magnesium  chloride  to  the 
extent  of  about  1.5  percent.  This  would  cause  an  additional  absorption 
of  moisture  so  as  to  bring  the  weight  up  to  7.5  percent  beyond  what  it 
normally  was. 

13.  Action  of  Thiocyanates  on  Wool. — According  to  Siefert,^  when 
wool  is  treated  with  a  solution  of  calcium  thiocyanate  and  then  steamed  a 
considerable  contraction  takes  place  without  injury  to  the  fiber;  conse- 
quently it  is  possible  to  produce  a  crepon  effect  in  this  manner  on  woolen 
cloth.  The  treated  wool  also  has  an  increased  affinity  for  acid  dyes,  but 
its  affinity  for  basic  dyes  is  reduced. 

1  Bull.  Soc.  Ind.  Miilh.,  1899,  p.  86. 


ACTION  OF  ZINC   SULFATE  175 

Crepon  effects  on  woolen  cloth  made  by  the  printing  on  of  chemicals 
which  cause  a  shrinkage  of  the  fiber  may  be  produced  by  several  methods. 
(1)  Schaeffer's  process  consists  in  printing  on  a  suitable  resist,  then 
treating  the  entire  fabric  with  a  strong  solution  of  sodium  bisulfite  and 
steaming.  This  causes  a  shrinkage  of  the  entire  piece  except  at  the  por- 
tions on  which  the  resist  is  printed.  (2)  Siefert's  process  consists  in  the 
use  of  calcium  or  barium  sulfocyanide  and  steaming.  It  has  been  shown, 
however,  that  though  when  once  produced  these  crepe  effects  are  very 
permanent  both  to  washing  and  stretching,  yet  the  cloth  when  printed  with 
sulfocyanide  is  very  tender  while  under  the  influence  of  steam,  and  cannot 
stand  any  degree  of  tension,  therefore  great  care  must  be  taken  in  the 
handling  of  the  goods.  Schoen  and  Grandmougin  in  reporting  on  Siefert's 
method  found  that  ammonium  sulfocyanide  causes  no  contraction  of  the 
fiber,  while  the  sulfocyanides  of  calcium  and  barium  do  produce  the 
effect. 

14.  Action  of  Zinc  Sulfate. — According  to  Kopp  ^  when  wool  cloth  is 
treated  with  a  solution  of  zinc  sulfate  of  high  density  a  creping  effect  is 
produced.  The  process  was  carried  out  commercially  in  the  following 
manner:  The  gray  wool  fabric  is  turned  piece  by  piece  in  a  wooden  vat 
containing  a  solution  of  zinc  sulfate  at  a  strength  of  500  grams  per  liter 
and  heated  to  the  boil  by  means  of  a  lead  coil.  After  treatment  in  this 
bath  the  goods  are  washed  in  boiling  water  until  no  longer  acid  to  litmus; 
they  are  then  bleached  and  chlorinated  in  the  usual  manner  for  printing. 
The  crepe  obtained  in  this  manner  is  said  to  withstand  the  various  opera- 
tions very  well  and  the  fabric  shows  very  little  tendency  to  turn  yellow  on 
steaming. 

15.  Treatment  with  Radium. — With  the  extension  of  radium  to  all 
manner  of  therapeutic  uses  it  is  natural  to  expect  that  the  salts  of  radium 
would  be  employed  in  connection  with  fabric  materials.  A  recent  patent 
relates  to  the  application  of  a  salt  of  radium  to  fibers,  and  consists  in 
taking  material  composed  of  vegetable  or  animal  fibers  and  first  cleansing 
and  drying  them.  The  fibers  thus  prepared  are  then  placed  in  a  suitable 
mordant — for  example,  either  in  a  10  percent  solution  of  tannic  acid  or  in 
a  concentrated  solution  of  alum,  and  then  dried  again  by  means  of  a  stove 
or  in  the  air,  according  to  their  nature.  They  are  then  placed  in  a  solution 
of  a  salt  of  radium,  the  percentage  being  determined  according  to  the 
strength  it  is  desired  to  obtain.  If,  for  example,  catgut  is  to  be  treated, 
the  solution  may  contain  20  mgm.  of  bromide  of  radium  per  cubic 
centimeter.  For  silk,  wool,  or  cotton  the  percentage  may  be  much 
higher.  In  general  the  fibers  should  not  remain  more  than  half  an  hour 
in  the  bath.  The  radium  is  fixed  on  the  fibers,  which  then  only  require 
to  be  dried.     This  method  of  fixing  the  radium  may  be  applied  to  the 

1  Bull.  Soc.  Ind.  Mulh.,  1894.  ^ 


176  ACTION  OF  CHEMICAL  AGENTS  ON   WOOL 

treatment  of  cloths,  silks,  wool,  cotton,  and  in  a  general  manner  to 
most  threads  and  fabrics.  It  imparts  to  these  latter  the  properties  of 
radiferous  substances,  and  consequently  renders  them  radioactive  with- 
out its  being  necessary,  in  order  to  fix  the  radium,  to  employ  any  varnish, 
gum,  or  other  foreign  adhesive  substance. 

16.  Action  of  Dyestuffs  on  Wool. — With  regard  to  coloring  matters 
wool  is  the  most  reactive  of  all  the  textile  fibers,  combining  directly  with 
acid,  basic,  and  most  substantive  dyestuffs,  and  yielding,  as  a  rule,  shades 
which  are  much  faster  than  those  obtained  on  other  fibers. 

There  have  been  various  opinions  put  forward  as  to  the  influence  in 
dyeing  of  the  active  chemical  groups  in  wool.  If  the  phenomena  of  dyeing 
were  princijoally  of  a  chemical  nature  we  would  expect  this  influence  to 
he  a  considerable  one.  In  the  case  of  acid  and  basic  dyes,  we  have  to 
deal  with  bodies  possessing  definite  chemical  characteristics — that  is  to  say, 
acid  dyes  are  acid  in  nature,  while  basic  dyes  have  basic  properties.  From 
the  facts  previously  put  forward,  that  wool  consists  principally  of  an 
amino  acid,  and  is  therefore  capable  of  exhibiting  both  acid  and  basic 
properties,  it  would  be  natural  to  expect  that  in  dyeing  with  acid  coloring 
matters  there  would  be  (to  some  degree  at  least)  the  formation  of  a  com- 
pound between  the  acid  of  the  dyestuff  and  the  base  of  the  wool.  Likewise, 
in  dyeing  with  basic  coloring  matters  the  basic  portion  of  the  dyestuff  would 
combine  with  the  acid  portion  of  the  wool.  That  such  a  combination  in 
reality  does  take  place  can  hardly  be  doubted,  for  many  experimental 
facts  have  been  adduced  leading  to  such  a  conclusion. 

In  the  dyeing  of  wool  with  acid  colors  it  is  generally  necessary  to  add 
sulfuric,  or  other  strong  acid,  to  the  dye-bath.  It  has  usually  been  the 
accepted  theory  that  these  dyes  are  sodium  salts  of  sulfonic  acids,  and 
that  the  addition  of  the  sulfuric  acid  causes  the  liberation  of  the  free  color- 
acid,  and  the  latter  then  combines  with  the  basic  group  of  the  wool  fiber. 
But  it  has  previously  been  pointed  out  that  wool  combines  readily  with 
sulfuric  acid,  and  that  wool  so  treated  can  dye  with  the  acid  colors  without 
further  addition  of  acid.  This  would  seem  to  indicate  that  the  basic 
group  of  wool  combines  with  sulfuric  acid,  and  consequently  the  presence 
of  the  latter  in  neutralising  the  basicity  of  the  wool  should  decrease  its 
affinity  for  acid  dyes,  according  to  the  above  view  of  the  dyeing  process; 
but  the  opposite  is  the  case.  Furthermore,  a  large  excess  of  sulfuric  acid 
above  the  amount  required  to  liberate  the  free  color-acid  of  the  dyestuff, 
should  prove  detrimental  to  the  dyeing.  Gelmo  and  Suida,^  who  have 
investigated  the  subject,  show  that  by  using  purified  wool  and  dyeing 
with  free  color-acids  the  intensity  of  the  resulting  color  is  independent  of 
the  presence  of  free  mineral  acid  in  the  dye-bath;    hence  they  conclude 

'  Monatsch.  /.  Chemie,  vol.  26,  p.  855. 


ACTION  OF  DYESTUFFS  ON  WOOL  177 

that  the  role  played  by  the  excess  of  acid  is  to  neutralise  the  lime  combined 
with  the  acid  groups  of  the  wool. 

Aside  from  the  fact  that  wool  combines  directly  with  acid  and  basic 
coloring  matters,  it  has  also  been  shown  that  when  the  active  chemical 
groups  in  the  fiber  are  neutraHsed  by  proper  chemical  treatment,  the 
reactivity  of  wool  toward  acid  and  basic  dyes  respectively  is  much 
decreased.  The  acid  nature  of  wool  may  be  almost  completely  neutralised 
by  acetylation  with  acetyl  chloride,  and  the  resulting  fiber  shows  but 
very  slight  reactivity  toward  basic  dyes,  and  a  correspondingly  increased 
reactivity  toward  acid  dyes. 

The  action  of  dyestuffs  on  the  fibers  has  also  been  explained  by  electrical 
effects.  Haldane,  Gee,  and  Harrison  ^  have  shown  that  the  average  value 
of  the  potential  difference  between  the  various  fibers  and  water  is  as 
follows : 

Cotton 0.06  volt 

Silk 0.22    " 

Wool 0.91    " 

This  seems  to  support  the  views  of  Pelet-Jolivet  and  Wild,  and  Knecht 
and  Battey,  that  dyestuffs  are  electrolytes,  and  ionisation  is  increased 
by  dilution  and  rise  of  temperature.  Wool  and  silk  becoming  negatively 
charged  when  in  contact  with  water,  it  is  natural  that  basic  dyestuffs 
(which  carry  a  positive  charge)  should  be  capable  of  dyeing  them  from 
neutral  solutions;  but  when  by  the  addition  of  acid,  the  electrical  condition 
of  the  fiber  is  changed,  the  affinity  for  these  dyestuffs  is  diminished,  while 
the  power  of  fixing  the  predominant  negative  ions  of  the  acid  dyes  is 
increased. 

Suida  has  found  that  when  wool  is  heated  with  acetyl  chloride  at  the 
temperature  of  the  water-bath  a  copious  evolution  of  hydrochloric  acid 
takes  place,  indicating  the  formation  of  an  acetyl  compound.  Wool, 
which  has  been  thus  treated  and  freed  from  all  excess  of  the  reagent  by 
alternate  rinsing  with  alcohol  and  water,  is  found  to  have  lost  to  a  great 
extent  its  affinity  for  the  basic  coloring  matters.  Wool  treated  with 
acetic  anhydride  shows  the  same  eifect.  Microscopical  examination  in 
both  cases  does  not  exhibit  any  structural  modifications  in  the  fiber.  On 
heating  wool  which  has  been  treated  in  this  manner  with  a  weak  solution 
of  ammonium  carbonate  (a  reagent  which  is  capable  of  saponifying  acetyl 
compounds),  the  wool  again  regains  its  normal  character  with  respect  to 
its  behavior  toward  basic  dyestuffs.  A  change  of  the  same  character  in 
wool  is  produced  by  heating  the  fiber  on  the  water-bath  with  alcohol  in 
the  presence  of  a  small  amount  of  strong  sulfuric  acid.     This  treatment 

^  Proc.  Faraday  Soc,  1910. 


178  ACTION  OF  CHEMICAL  AGENTS   ON  WOOL 

also  appears  to  form  an  ester  which  is  saponified  by  treatment  afterward 
with  an  alkah,  so  that  the  wool  regains  its  original  condition. 

17.  Efifect  of  Mordanting  and  Dyeing  on  Wool. — Kapff  made  some 
experiments  on  the  weakening  of  wool  in  the  dyeing  operations.  The 
dyeing  was  carried  out  on  the  wool  in  the  form  of  slubbing  which  was  then 
spun  into  yarns  of  which  the  tensile  strength  was  tested.  His  results  were 
as  follows:^ 

Kilos. 

1.  White  wool 2.595 

2.  Wool  dyed  medium  indigo  blue 2 .  603 

3.  Wool  dyed  deep  indigo  blue 2.581 

4.  Wool  dyed  indigo  and  alizarine  (0.9  percent  of  bichro- 

mate and  1.2  percent  of  formic  acid) 2. 315 

5.  Wool  chromed  2  percent  bichromate 1 .  878 

6.  Wool  chromed  1  percent  bichromate 1 .  979 

7.  Wool  dyed  with  alizarine  (mordanted  with  1.5  percent 

bichromate  and  2  percent  of  formic  acid) 2 .  179 

In  addition  a  series  of  tests  were  carried  out  for  measuring  the  resist- 
ance of  the  samples  to  twisting,  with  the  following  results: 

Turns. 

White  wool 385 

Indigo  medium 345 

Indigo  deep 320 

Indigo  and  alizarine 245 

Wool  mordanted  as  No.  7 105 

Wool  dyed  and  treated  with  2  percent  of  bichromate  and 

2  percent  Monopole  soap 80 

Wool  as  the  preceding  test  without  soap 48 

^  Woolen  fabrics  are  more  or  less  tendered  by  the  various  operations  through  which 
they  pass  during  manufacturing,  as  these  involve  more  or  less  deterioration  in  strength 
and  durability.  The  mechanical  rubbing  and  stretching,  the  action  of  heat  and  the 
chemicals  employed  in  dyeing,  bleaching  and  mordanting  all  contribute  to  this  deterio- 
ration of  the  fiber.  While  such  injury  to  some  extent  must  of  necessity  occur,  yet  it 
is  important  that  it  be  reduced  to  a  minimum,  otherwise  the  market  value  of  the 
goods  will  be  affected.  Kapff,  Kertesz  and  Leygert  have  examined  the  effect  of 
various  mordants  and  dyes  and  also  of  milling  on  the  strength  of  woolen  fabrics,  but 
their  conclusions  differ  in  many  important  details.  Kapff  states  that  breakages  in 
spinning  are  far  greater  in  dyed  than  in  undyed  wool,  except  in  the  case  of  indigo; 
the  vat  dyes  appear  to  be  the  least  injurious  to  wool  of  all  classes  of  dyestuffs.  Some 
claim  that  wool  suffers  most  in  piece  dyemg,  while  others  claim  that  the  deterioration 
is  greater  if  the  wool  is  dyed  before  being  spun.  There  is  a  general  opinion,  however, 
that  machine  dyeing  tends  to  the  better  preservation  of  the  fiber.  It  is  said  that 
much  harm  is  done  to  wool  by  the  after-chroming  process,  the  chromic  acid  being 
free  for  a  comparatively  long  time  and  thus  acting  on  the  fiber,  whereas  in  previously 
mordanting  the  chromic  acid  is  reduced  and  is  harmless.  Robson  favors  the  use  of 
the  rubbing  machine  rather  than  the  dynamometer  for  the  testing  of  woolen  fabrics, 
and  this  will  more  truthfully  represent  the  wearing  quality  and  durability  of  the  fiber 


EFFECT  OF   MORDANTING   AND   DYEING  ON   WOOL 


179 


Kertesz,  however,  in  analysing  these  results  disputes  the  correctness  of 
their  conclusions,  as  being  in  contradiction  to  the  well-known  results  ob- 
tained in  practice.  Kertesz  made  rather  extensive  experiments  in  this 
connection  and  his  results  are  shown  in  the  following  table : 


Breaking  Tests  of 
the  Worsted 
Yarns  52/1 

Treated  in  Form 
of  Cops. 

Breaking  Tests  of 
the  Worsted 
Yarns  30/2. 

Breaking 

Strain 
at  Kilos. 

Elas- 
ticity in 
Cm. 

Breaking 

Strain 
at  Kilos. 

Elas- 
ticity in 
Cm. 

No.  1.    Undyed  Wool 

Raw  Yarn. 

37.18 

10.66 

48.10 

14.58 

No.  2.    Treated  with  Bistjlfate 
OF  Soda 

Wet  the  cops  for  20  minutes  at  50°  C,  then 
add 

10  percent  bisulfate  of  soda 
to  the  fresh  bath;    raise  the  temperature  from 
40°  to  95°  C.  in  ^  hour,  treat  for  ^  hour  at 
95°  C,  and  then  rinse  with  cold  water  for  10 
minutes. 

41.86 

11.40 

55.12 

13.36 

No.  3.    With  Formic  Acid 

Same  as  No.  2,  with 

4  percent  formic  acid  (85%). 

41.90 

11.40 

56.16 

13.62 

No.  4.    Previously  Mordanted 

Wet  like  No.  2.     Mordant  in  a  fresh  bath 
with 

3  percent  bichrome. 
2  percent  tartar. 
Commence  at  80°  C,  treat  for  1§  hours  at 
95°  C.,  then  rinse  same  as  No.  2. 

38.74 

10.40 

49.84 

11.98 

No.  5.    Previously  Mordanted 

Mordanted  like  No.  4,  with 
1.5  percent  bichrome. 
2  percent  formic  acid  85  percent. 

40.95 

10.64 

52.78 

12.50 

No.  6.    After-chromed 

Wet  like  No.  2,  then  treat  in  a  fresh  bath 
with 

10  percent  bisulfate  of  soda; 
commence  at  40°  C,  raise  in  ^  hour  from  40°  to 
95°  C,  and  treat  for  f  hour  at  95°  C.     Then 
chrome  for  |  hour  with 

1.5  percent  bichrome 
at  95°  C,  and  rinse  same  as  No.  2. 

41.80 

10.80 

52.69 

12.36 

180 


ACTION   OF   CHEMICAL  AGENTS   ON   WOOL 


Breaking  Tests  of 

the  Worsted 

Yarns  52/1 

Treated  in  Form 

of  Cops. 

Breaking  Tests  of 
the  Worsted 
Yarns  30/2. 

Breaking 

Strain 
at  Kilos. 

Elas- 
ticity in 
Cm. 

Breaking 

Strain 

at  Kilos. 

Elas- 
ticity in 
Cm. 

No.    7.      Aii'TER-CHROMED 

Treat  same  as  No.  6,  with 

3  percent  formic  acid  (85%), 
then  chrome  with 

1.5  percent  bichrome. 

42.73 

10.20 

52.80 

12.44 

No.  8.    After-chromed 

Treat  same  as  No.  6,  with 

10  percent  bisulfate  of  soda, 
then  chrome  with 

3  percent  bichrome. 

41.60 

10.10 

51.35 

12.68 

No.  9.    After-chromed 

Treat  same  as  No.  6,  with 

4  percent  formic  acid  (85%), 
and  chrome  with 

3  percent  bichrome. 

41.56 

10.92 

52.52 

12.88 

No.  10.    After-chromed 

Same  as  No.  8,  except  that 

3  percent  Monopole  soap 
are  added  besides. 

43.30 

10.78 

54.99 

13.30 

No.  11.    Dyed  on  Previously  Mordanted 
Material 

Mordant  same  as  No.  4,  then  dye  with 
Anthracene  Acid  Black  D  S  N. 
Commence  at  40°  C,  raise  the  temperature  in 
^  hour  to  95°  C,  and  dye  for  I5  hours  at  95°  C; 
add 

3  percent  formic  acid  (85%) 
in  order  to  exhaust  the  bath.     After  dyeing, 
rinse  for  10  minutes. 

39.91 

11.40 

49.23 

11.62 

No.  12.    Dyed  on  Mordanted  Goods 

Mordanted  same  as  No.   5,   dyed  same  as 
No.  11. 

40.95 

10.60 

51.35 

11  80 

No.  13.    Dyed  on  Mordanted  Goods 

Mordanted  same  as  No.  4,  dyed  with 
3.5  percent  Anthracene  Chrome  Blue  G; 
otherwise  same  as  No.  11. 

41.34 

11.20 

51.22 

12.46 

No.  14.    Dyed  on  Mordanted  Goods 

Mordanted   same  as   No.   5,   dyed  same  as 
No.  13. 

41.34 

11.46 

52.00 

12.76 

EFFECT  OF   MORDANTING   AND   DYEING   ON   WOOL 


181 


No.  15.    Chromed  After  Dyeing 
Wet  same  as  No.  2.     Dye  in  a  fresh  bath 
with 

6  percent  Anthracene  Acid  Black  D  S  N; 
commence  at  40°  C,  add 

3  percent  formic  acid  (85%), 
raise  in  ^  hour  to  95°  C,  and  dye  for  |  hour  at 
95°  C.     Then  add 

1.5  percent  bichrome, 
treat  for  ^  hour  at  95°  C,  and  rinse. 

No.  16.    Chromed  After  Dyeing 
Same  as  No.  15,  only  dyed  with 

10  percent  bisulfate  of  soda 
instead  of  with  formic  acid. 

No.  17.    Chromed  After  Dyeing 
Dyed  same  as  No.  15,  with 
3.5  percent  Anthracene  Chrome  Blue  G, 

3  percent  formic  acid  (85%), 
after-treated  with 

1.5  percent  bichrome. 

No.  18.    Chromed  After  Dyeing 
Same  as  No.  17,  only  dyed  with 

10  percent  bisulfate  of  soda 
instead  of  formic  acid. 

No.  19.    Chromed  After  Dyeing 
Dyed  same  as  No.  15: 
6  percent  Anthracene  Chrome  Black  F. 

4  percent  formic  acid  (85%). 
3  percent  bichrome. 

No.  20.    Chromed  After  Dyeing 
Same  as  No.  19,  only  dyed  with 

10  percent  bisulfate  of  soda 
instead  of  formic  acid. 

No.  21.    Indigo  Pale  Shade 
Wet  same  as  No.  2,  then  dye  in  a  fresh  bath 
with 

Indigo  Vat  MLB, 
with  the  addition  of  a  little  ammonia  and  some 
glue  solution.     Dye  in  one  dip  for  25  minutes  at 
50°  C,  then  rinse,  sour  off  with  acetic  acid,  and 
rinse  again. 

No.  22.    Indigo,  Deep  Shade 
Dyed  same  as  No.  21,  with  3  dips. 


Breaking  Tests  of 
the  Worsted 
Yarns  52/1 

Treated  in  Form 
of  Cops. 


Breaking 

Strain 

at  Kilos. 


41.80 


41.20 


42.50 


42.14 


43.50 


43.34 


41.60 


Elas- 
ticity in 
Cm. 


10.98 


10.90 


10.70 


10.86 


10.82 


10.78 


11.52 


Breaking  Tests  of 
the  Worsted 
Yarns  30/2. 


Breaking 

Strain 

at  Kilos. 


52.15 


52.00 


52.39 


52.20 


51.06 


52.00 


49.34 


39.65       10.68        49.02       12.34 


Elas- 
ticity in 
Cm. 


11.78 


12.34 


12.46 


12.42 


12,76 


12.70 


12.62 


182 


ACTION  OF  CHEMICAL  AGENTS  ON  WOOL 


18.  Mildew  in  WooL — If  wool  is  left  in  a  warm  place  in  a  moist  con- 
dition so  that  the  fiber  does  not  have  free  access  to  plenty  of  fresh  air, 
it  will  soon  develop  in  spots  a  fungoid  growth  or  mildew.  This  causes 
the  fiber  to  become  tender  and  eventually  rot.  This  fungoid  growth  will 
develop  without  any  sizing  ingredients  or  other  foreign  matter  being 
present  on  the  fiber.  It  rapidly  attacks  the  scales  on  the  surface  of  the 
fiber,  and  then  eats  into  the  inner  substance  of  the  wool.  Under  the 
microscope  (see  Fig.  77)  this  fungoid  growth  appears  as  two  forms:    (a) 

Small  elliptical  cells  which  adhere  to 
the  surface  of  the  fiber  and  spread  out 
from  it;  and  which  seem  to  colonise 
especially  at  the  joints  of  the  scales; 
(6)  a  tree-like  growth  consisting  of 
several  cells  joined  together  and  branch- 
ing off  from  one  another;  these  grow 
over  the  fiber  as  a  kind  of  filmy  in 
tegument,  and  do  not  appear  to  cor- 
rode the  wool  as  rapidly  as  the  first 
kind  of  cells.  Mildew  is  especially  apt 
to  develop  on  woolen  material  which 
contains  a  small  amount  of  alkali,  the 
alkaline  reaction  probably  being  favor- 
fungus  growing  in  isolated  cells,  able  to  the  growth  of  the  fungus.  Hence 
(Micrograph  by  author.)  the  tendency  of  wool  dyed  in  the  indigo- 

vat  to  develop  mildew  stains. 
Kalman  ^  has  made  a  careful  investigation  of  mildew  in  wool  and  gives 
the  following  summary  of  his  results:  (1)  Mildew  is  caused  by  definite 
kinds  of  bacteria;  (2)  these  bacteria  are  very  sensitive  toward  acids 
(either  organic  or  inorganic);  (3)  pieces  dyed  in  acid  baths  therefore  are 
not  liable  to  develop  mildew;  (4)  if  mildew  spots  show  up  in  such  pieces 
after  dyeing,  such  spots  were  present  in  the  goods  previous  to  dyeing; 
(5)  mildew  develops  most  rapidly  in  wool  which  has  been  treated  in 
alkahne  baths;  (6)  Indigo  Blue  is  destroyed  by  the  mildew  bacteria, 
consequently  such  spots  show  up  in  vat-dyed  blues  as  white  stains;  (7) 
many  dyes  appear  to  kill  the  mildew  bacteria,  as  for  example,  Methylene 
Blue,  for  wool  dyed  with  this  color  and  showing  an  alkaline  reaction 
will  not  develop  mildew. ^ 

1  Farber-Zeit.,  1902,  pp.  245,  341,  and  377. 

2  See  also  Schimke,  Farber-Zeit.,  1892,  p.  290. 


Fig.  77. — Wool  Fibers  Attacked  by 
Mildew.  (X300.)  o,  Fungus  grow- 
ing  in    jointed    cells,    tree-like;   b, 


CHAPTER  VII 
RECLAIMED   WOOL  AND  SHODDY 

1.  Recovered  Wool. — Besides  the  natural  varieties  of  wool  which 
find  applications  in  the  textile  industries  we  have  a  large  quantity  of 
recovered  wool  employed  as  a  textile  fiber.  The  recovery  of  wool  fiber 
from  rags  and  the  spinning  of  shoddy  yarns  were  introduced  first  into 
England  in  1813,  and  did  not  spread  to  the  Continent  until  about  1850. 
In  1852  Kober,  in  Kannstatt,  discovered  the  process  of  carbonising,  and 
this  made  possible  the  recovery  of  wool  fiber  from  mixed  wool-cotton  rags 
and  waste.^ 

Shoddy  is  obtained  by  tearing  up  woolen  rags  and  waste  (a  process 
known  as  "  garnetting,"  being  equivalent  to  a  coarse  carding),  conver+'ng 
it  back  into  the  loose  fiber  and  spinning  it  over  again,  either  alone  or  in 
admixture  with  varying  proportions  of  pure  fiber  or  fleece  wool.  This 
artificial  wool^  or  wool  substitute,  as  it  is  frequently  called,  is  also  obtained 
from  rags  and  waste  containing  wool  and  cotton,  or  even  silk;  the  vege- 
table fiber  being  destroyed  by  chemical  treatment,  thus  leaving  the 
animal  fiber  to  be  extracted  and  used  again.  On  this  account  it  is  some- 
times known  as  extract  wool.  The  industry  of  converting  recovered 
fiber  into  yarns  and  fabrics  has  assumed  of  late  enormous  proportions, 
and  nearly  all  cheap  woolen  goods  contain  a  high  percentage  of  these  wool 
substitutes  in  their  composition.^ 

^  Beaumont  estimates  (1921)  that  in  the  United  Kingdom  there  is  a  yearly  con- 
sumption of  350,000,000  lbs.  of  fleece  wool,  200,000,000  lbs.  of  recovered  wool  (from 
rags)  and  30,000,000  lbs.  of  noils.  The  world's  wool  supply  without  the  addition  of 
the  recovered  wool  would  be  inadequate  to  meet  the  industrial  demands.  The  total 
supply  of  fleece  wool  throughout  the  world  for  1913  was  estimated  at  2,800,000,000  lbs., 
of  which  1,074,000,000  lbs.  were  merino,  1,022,000,000  lbs.  cross-bred,  and  700,000,000 
lbs.  were  coarse  wool. 

2  Artificial  wool  is  not  a  good  term  for  this  class  of  fiber,  as  the  material  is  not 
artificial  in  the  sense  of  being  made  like  artificial  silk;  it  is  a  real  wool  fiber  and  similar 
to  the  natural  fleece  wool  in  every  particular  as  to  composition  and  nature.  It  is 
really  a  by-product  recovered  from  waste  woolen  materials  and  is  simply  the  true 
woolen  fiber  taken  out  of  its  manufactured  form  and  converted  back  into  the  fiber 
condition  again. 

^  Recovered  wool  is  almost  entirelj^  employed  in  the  woolen  trade  and  practically 
none  enters  the  worsted  trade.  Of  the  fleece  wool  consumed  in  the  United  States 
about  one-half  goes  into  the  manufacture  of  woolen  goods  and  the  other  half  into 

183 


184 


RECLAIMED   WOOL  AND   SHODDY 


The  various  classes  of  reclaimed  wools  or  shoddies  and  pulled  yarn 
waste  are  employed  in  the  manufacture  of  a  great  variety  of  fabrics. 
Beaumont  furnishes  the  following  representative  classes  of  cloths : 

Group  I.  Fabrics  in  which  both  the  warp  and  filhng  yarns  are  made  of  shoddy, 
including  tweeds,  pilots,  friezes,  napps,  meltons,  rugs  and  blankets. 

Group  II.  Fabrics  having  a  cotton  warp  crossed  with  a  mimgo  or  shoddy  filling 
yarn,  including  face-costume  cloths,  beavers,  raised-pile  fabrics,  figm-ed  rugs  and 
decorative  fabrics. 

Group  III.  Fabrics  having  a  worsted  warp  crossed  with  a  cotton  filling  (face) 
and  also  mungo  or  shoddy  filling  (back),  including  union  worsteds,  coatings  and 
suitings. 

Group  IV.  Fabrics  having  a  cotton  warp  crossed  with  a  worsted  face  yarn  and  a 
mungo  or  shoddy  backing  yarn,  including  union  worsteds,  dress  and  mantle  cloths. 

Group  V.  Fabrics  compound  in  structure  and  made  of  various  counts  and  qualities 
of  yarns,  including  union  compound-make  cloths,  reversibles  and  lined  overcoatings. 


Fig.  78. — Various  Kinds  of  Shoddy:  (1)  Mungo;  (2)  shoddy  from  black  stockings;  (3) 
from  knitted  fabric;  (4)  from  dyed  cheviot;  (5)  from  angalo  waste;  (6)  black 
extract  wool;  (7)  silk  waste;  (8)  from  pulled  alpaca  oil  bags.  Lines  1  inch  apart. 
(Tetley.) 

2.  Classification  of  Recovered  Wool. — Depending  on  its  source  of 
production,  recovered  wool  will  vary  largely  in  its  quality,  and  according 
to  its  origin  and  nature  it  is  classed  under  several  names.  Beaumont 
states  that  there  are  obviously  two  general  classes  of  recovered  wool 

worsted  goods.     Besides  this  the  woolen  industry  uses  about  25  percent  of  recovered 
wool,  while  the  worsted  industry  uses  only  about  1  percent. 


CLASSIFICATION   OF   RECOVERED   WOOLS 


185 


products,  as  follows:  (o)  the  fiber  resulting  from  cast-off  clothing  and 
worn-out  domestic  fabrics  described  loosely  as  rags,  in  which  arc  also 
included  tailors'  clippings,  remnants  and  bits  of  new  cloth;  and  (fe)  the 
fiber  resulting  from  the  waste  made  in  manufacturing  processes  of  spinning 
and  weaving.  The  second  class  is  known  as  soft  material,  not  having 
been  previously  made  into  woven  or  knitted  textures. 

Reclaimed  or  recovered  wool  comprises  shoddies,  mungos,  waste, 
extract,  noils  and  flocks,  and  may  be  broadly  classified  as  follows 
(Beaumont) : 

1.  Mungoes,  from  old  and  new  rags  of  a  fulled  or  firm  structure. 

2.  Shoddies,  from  serges,  cheviots  and  flannels,  scarfs,  stockings  and  knitted  goods. 

3.  Extract,  from  woolen  and  worsted  fabrics  partially  made  up  of  cotton. 

4.  Noils,  a  by-product  in  the  production  of  wool-combing. 

5.  Waste  from  carding  and  spinning. 

6.  Waste  from  warping  and  weaving. 

7.  Flocks  or  waste  recovered  from  scouring,  fulling  and  shearing. 


Barker  furnishes  the  following  tabular  comparison  of  different  varie- 
ties of  reclaimed  woolen  materials: 


Noil. 

Mungo. 

Shoddy. 

Extract. 

Flocks. 

Sources 

Combed  wool 

Hard  woolen 

Soft  knitted 

Hard  union 

Woolen  goods 

and  worsted 

goods 

goods 

cloths 

Color  and 

Various, 

Various,  not 

Various,  lus- 

\'arious, not 

Various 

luster 

longer  fiber 
lustrous 

lustrous 

trous 

lustrous 

Fineness,  ins. 

1/400  to 

1/SOO  to 

1/600  to 

1/SOOto 

1/400  to 

1/1500 

1/lSOO 

1/1200 

1/1500 

1/1500 

Length,  ins. 

Ho2i 

i  tn  a 

i  to  2 

Itof 

ito^ 

Appearance 

Open  and 

Matted  and 

Fairly  open 

Fairly  matted 

Curly  and 

flaky 

threaded 

and  fluffy 

and  thready 

fluffy 

Handle 

Fairly  soft 

Soft 

Soft 

Harsh 

Fairly  soft 

3.  Shoddy. — Though  this  name  is  frequently  applied  to  all  manner  of 
recovered  fiber,  it  is  more  specifically  used  to  designate  that  which  is 
derived  from  all-wool  rags  or  waste  which  have  not  been  felted,  or  only 
to  a  slight  degree,  also  from  knit  goods,  shawls,  flannels,  and  similar 
fabrics;  also  yarn  and  fabric  waste  from  manufacturing  processes.  These 
materials  are  known  in  trade  as  "  softs."  They  yield  the  best  quality  of 
fiber,  the  average  length  of  which  is  about  1  in.,  while  the  variation  in 
length  is  from  1.4  to  0.2  in.  In  many  cases  it  is  equal  in  quality  to  a 
fair  grade  of  fleece  wool,  and  is  used  in  the  production  of  many  high- 


186  RECLAIMED   WOOL  AND   SHODDY 

grade  fabrics.  Shoddy  is  occasionally  spun  up  alone  into  rather  coarse 
counts  of  yarn;  but  it  is  more  often  mixed  with  fleece  wool  and  manu- 
factured into  a  variety  of  average  grade  yarns. 

For  the  manufacture  of  shoddy  from  rags  the  material  is  first  sorted 
with  reference  to  the  following  points:  (a)  whether  pure  wool  or  mixed 
fibers;  (6)  for  kind  of  fabric,  whether  knitted  or  woven,  fulled  or  unfulled; 
and  (c)  according  to  color.  Then  buttons,  hooks,  and  trimmings  are  clipped 
off.  The  rags  are  then  purified  from  dirt  by  treatment  in  a  machine  known 
as  a  "  shaker,"  or  by  scouring  in  a  washer.  After  cleaning,  those  rags  wl  ich 
contain  cotton  or  other  vegetable  fibers  must  be  carbonised.^  At  the 
present  time  small  establishments  employ  sulfuric  acid  for  this  purpose, 
but  larger  works  use  hydrochloric  acid  gas  in  a  special  form  of  apparatus. 
After  carbonising  the  rags  are  neutralised,  washed,  dried,  and  are  passed 
through  willows  to  dust  out  the  decomposed  vegetable  matter,  and  then 
through  garnetting  machines  to  tear  the  rags  up  into  the  fiber  form. 

4.  Mungo. — This  refers  to  the  fiber  -  obtained  from  woolen  material 
which  has  been  fulled  or  felted  considerably;  to  disintegrate  the  rags  the 
fibers  must  be  torn  apart,  and  consequently  it  yields  fibers  of  shorter 
staple  and  less  value  than  the  preceding.  The  length  of  fibers  in  n.iingo 
varies  from  0.8  to  0.2  in.;  and  on  this  account  is  never  worked  up  alor.o 
into  yarn,  but  is  mixed  with  new  wool  or  cotton  and  generally  spun  into 
low  counts  of  filling  yarn.  Since  mungo  consists  of  a  fiber  which  has 
already  been  heavily  felted,  it  is  easy  to  understand  that  it  will  have 
lost  much  of  its  capacity  for  further  felting. 

Beaumont  points  out  that  the  quality  and  make  of  the  fabric,  whether 
worn  or  unworn,  determines  the  quality  of  the  mungo  or  shoddy  obtainable 
by  rag  grinding.  Fabrics  of  the  beaver  class,  made  of  fine,  short  wools, 
yield  a  good  sound  mungo;  fabrics  of  the  tweed  class,  made  of  medium 
stapled  wools  and  strong  in  fiber,  yield  a  springy  or  soft-handling  shoddy. 
Serge  and  flannel  would  give  two  varieties  of  shoddy,  the  one  of  a  full,  flex- 
ible character,  and  the  other  of  softer  and  finer  staple,  but  both  of  satis- 
factory spinning,  fulling  and  finishing  properties. 

5.  Extract  Wool. — This  is  obtained  from  mixed  wool  and  cotton  rags 
and  waste,  and  has  to  undergo  the  process  of  carbonisation,  whereby  the 
vegetable  fiber  is  destroyed.  This  process  is  generally  carried  out  by 
steeping  the  rags  in  a  solution  of  sulfuric  acid  (6°  Tw.)  at  140°  to  180°  F. 
and  then  drying,  whereupon  the  vegetable  fibers  are  decomposed  and  are 

1  See  Schwartz,  Fdrber-Zeit.,  1908,  p.  66. 

2  Beaumont  gives  the  following  interesting  derivation  of  the  word  "mungo." 
Samuel  Parr,  of  Batley,  in  1834  carried  out  experiments  in  rag  pulling,  and  from  the 
resultant  material  he  made  some  goods  which  were  offered  for  sale  at  Ossett,  near 
Wakefield.  One  buyer  observing  "I  daart  it  winnot  goa,"  Parr  replied,  "Winnot 
goa?     It  mun  goa."     From  this  assertion  the  term  mungo  was  derived. 


EXTRACT  WOOL 


187 


easily  dusted  out  by  willowing,  the  wool  fibers  being  scarcely  affected. 
The  excess  of  acid  is  then  removed  by  treatment  with  soda  ash  and  washing. 
The  fibers  obtained  are  sometimes  over  1  in.  in  length.  Extract  wool 
is  some  called  alpaca,  and  varies  much  in  its  length  of  staple  and  other 
qualities. 

In  the  acid  treatment  of  rags,  for  the  removal  of  the  excess  of  acid, 
hydroextracting  is  preferable  to  passing  through  squeeze  rolls,  as  the  rags 
are  left  in  a  freer  working  condition.  The  drying  is  sometimes  done  by 
conveying  the  rags  over  steam  cylinders  heated  to  260°  to  300°  F.,  but  if 
this  is  done  the  rags  must  be  rapidly  passed  through  the  machine  or  the 
wool  will  be  made  brittle.  When  ordinary  drying  apparatus  is  used  the 
temperature  is  generally  run  at  210°  F,     At  this  temperature  the  acid 


Fig.  79. — Carbonising  Machine  for  Hydrochloric  Acid  Gas.  A,  Revolving  drum  for 
rags  or  material  to  be  treated;  B,  retort  located  in  furnace  for  generating  gaseous 
hydrochloric  acid. 


becomes  concentrated  and  its  action  on  the  vegetable  substance  is  to  turn 
it  black  and  reduce  it  to  a  charred  or  "  carbonised  "  condition. 

The  sulfuric  acid  treatment  has  gradually  given  place  to  the  more  mod- 
ern hydrochloric  acid  gas  method  of  carbonising.  The  important  factors 
in  favor  of  this  process  are  its  convenience  and  simplicity,  and  it  enables 
the  carbonising  to  take  place  at  a  lower  temperature  so  that  the  softness 
and  luster  of  the  wool  fiber  is  better  preserved.  It  also  allows  of  the  rags 
being  treated  in  the  dry  condition,  which  is  beneficial  to  the  good  properties 
of  the  wool,  for  in  the  older  sulfuric  acid  method,  where  very  thorough  wash- 
ing had  to  be  done  after  the  acid  treatment,  the  wool  was  liable  to  be  much 
damaged  and  felted.  The  apparatus  employed  for  gas  carbonising  is 
usually  a  large  drum  or  cylinder  revolving  in  an  enclosed  chamber  (Fig.  79). 
Accessory  apparatus  is  provided  for  generating  and  supplying  the  hydro- 


1S8  RECLAIMED  WOOL  AND  SHODDY 

chloric  acid  gas,  which  passes  through  the  rags  and  brings  about  the  car- 
bonisation of  the  cotton.  Or  the  rags  may  simply  be  treated  with  the 
gas  on  tables  in  an  enclosed  chamber,  or  in  trucks  (as  in  Fitton's  form  of 
apparatus).  After  treating  with  the  hot  gas  the  rags  are  run  through  a 
machine  known  as  a  "  wincey,"  which  is  a  centrifugal  machine  to  shake  out 
the  dust  from  the  rags.  The  rags  then  pass  to  the  "  shaker  "  machine  and 
finally  to  the  grinder. 

6.  The  Carbonising  Process  as  Related  to  Wool. — Though  the  process 
of  carbonising  really  consists  in  the  action  of  acids  or  acid  substances  on 
cotton  (or  other  vegetable  matter)  with  but  little  chemical  action  on  the 
wool  fiber,  nevertheless  it  is  the  wool  that  is  desired  as  a  product  of  this 
process,  and  as  the  good  qualities  of  the  fiber  depend  to  a  great  extent  on 
the  conditions  of  the  carbonising  operations  it  is  proper  to  consider  this 
process  as  one  relating  in  a  commercial  and  manufacturing  sense  to  wool 
rather  than  to  cotton. 

The  carbonising  process  of  late  years  has  been  much  extended  in  the 
woolen  industry  beyond  that  of  recovering  wool  fiber  from  rags,  as  in  the 
production  of  shoddy.  Many  varieties  of  loose  fleece  wool,  after  being 
scoured,  are  carbonised,  before  undergoing  further  manufacturing  opera- 
tions, for  the  purpose  of  purifying  the  fiber  from  all  vegetable  matter 
and  burrs.  In  finishing  operations  a  carbonising  treatment  is  frequently 
given  to  cloth  for  the  same  purpose,  and  this  often  is  true  for  the  highest 
grades  of  fabrics  where  it  is  desirable  to  remove  every  trace  of  vegetable 
impurity. 

7.  Sulfuric  Acid  Process. — In  carbonising  with  sulfuric  acid  there  are 
several  features  to  be  observed  to  get  good  results  with  the  least  injury 
to  the  wool  fiber,  it  being  understood,  of  course,  that  in  any  carbonising 
operation  the  vegetable  fiber  must  be  completely  destroyed.  One  of  the 
most  important  factors  in  the  process  is  the  proper  conti'ol  of  the  tem- 
perature. According  to  Ganswindt,  as  far  as  the  wool  itself  is  concerned,  a 
temperature  of  176°  to  212°  F.  answers  the  requirements  of  the  carbonising 
process.  If  the  wool  is  impregnated  with  weak  or  concentrated  solutions 
of  sulfuric  acid  at  a  temperature  within  these  limits,  it  becomes  intimately 
combined  with  certain  proportions  of  sulfuric  acid  so  that  the  acid  cannot 
be  removed  from  the  wool  even  by  repeated  rinsing.  The  sulfuric  acid 
does  not  weaken  the  wool  fiber  in  the  slightest  degree.  The  combination 
of  the  acid  and  the  fiber  is  so  stable  that  it  is  not  affected  when  the  wool 
is  subjected  to  damp  heat  for  an  hour  or  more.  It  is,  however,  sensitive 
to  dry  heat,  the  tendering  of  the  wool  taking  place  either  (1)  by  the  action 
of  the  sulfuric  acid  on  the  wool  fiber  at  a  dry  heat,  or  (2)  by  the  action  of  a 
high  temperature  on  the  wool,  irrespective  of  the  sulfuric  acid.  The 
Lasbordes  process,  employs  a  very  weak  solution  of  sulfuric  acid  and  a 
carbonising  temperature  of  122°  F.,  but  such  a  low  temperature  will  not 


SULFURIC  ACID  PROCESS  189 

answer  for  carbonising.  Reinartz  has  shown  that  under  certain  conditions 
complete  carbonising  will  result  at  a  temperature  of  131°  F.  He  recom- 
mends, on  the  strength  of  his  experiments,  that  the  piece-goods  be  immersed 
in  a  warm  solution  of  the  carbonising  agent,  and  then  dried  on  a  tentering 
machine  at  131°  F.  Even  at  this  moderate  temperature  a  large  number 
of  the  burrs  and  seeds  are  carbonised,  the  remainder  being  readily  crushed, 
this  being  proof  that  with  a  2°  Be.  solution  of  sulfuric  acid  it  is  not  neces- 
sary to  raise  the  temperature  above  131°  F.^ 

After  drying  the  carbonised  wool  at  a  high  temperature,  the  next  proc- 
ess is  dusting.  This  is  purely  a  mechanical  process,  and  the  object  is  to 
remove  the  carbonised  vegetable  material  from  the  wool.  In  the  case 
of  loose  wool,  dusting  may  sometimes  be  omitted,  as  the  carbonised  burrs 
and  seeds  are  removed  by  the  preparatory  processes,  picking,  and  carding. 

The  material,  after  dusting,  consists  of  wool  impregnated  with  dilute 
acid,-  as  the  wool  fiber  remains  merely  saturated  with  the  acid  at  a  tem- 
perature of  180°  to  212°,  when  the  vegetable  substances  are  carbonised 
at  that  temperature.  The  object  of  the  neutralising  process  is  to  remove 
the  acid  remaining  in  the  wool.  For  this  purpose  the  wool  is  treated  in  a 
solution  of  soda.  Under  ordinary  conditions  the  treatment  of  wool  in  a 
solution  of  soda  would  not  be  entirely  harmless;  but  in  the  case  of  car- 
bonising the  wool  is  loaded  with  sulfuric  acid,  which  prevents  injury  to 
the  fiber  by  the  soda.  A  soda  solution  of  3°  to  5°  Be.  is  used.  The  pres- 
ence of  acid  in  the  wool  may  also  cause  trouble  in  the  subsequent  process 
of  dyeing,  as  the  wool  carrying  acid  will  take  a  different  shade  from  that 
taken  by  wool  free  from  acid. 

The  strength  of  the  soda  solution  must  be  determined  by  experiment 
in  each  case.  The  acid  combines  with  the  alkali  to  form  sulfate  of  soda. 
The  amount  of  alkali  needed  thus  depends  directly  on  the  quantity  of  acid 
in  the  wool.  The  best  plan  is  to  determine  the  exact  quantity  of  acid 
present  by  testing  1  to  2  ozs.  of  the  wool.  It  is  as  important  to  avoid 
leaving  an  excess  of  alkali  in  the  wool  as  it  is  to  remove  all  of  the  acid, 
because  the  alkali  attacks  the  wool  fiber.  The  right  quantity  of  alkali 
to  be  used  is  determined  by  tests  with  litmus  paper. 

1  The  impregnation  of  the  material  with  the  dilute  acid  hquor  should  take  place 
at  normal  room  temperature,  as  under  these  conditions  it  is  claimed  that  the  cotton 
will  rapidly  absorb  the  acid,  while  the  surface  of  the  wool  only  will  be  coated  with 
the  Uquid,  as  a  result  of  which  the  acid  will  not  penetrate  to  the  interior  of  the  wool 
fiber.  By  carefully  carrying  out  the  operations,  the  wool  can  be  left  with  only  a  trace 
of  the  acid,  while  the  vegetable  material  is  thoroughly  saturated. 

^  The  concentration  of  the  acid  in  the  wool  after  heating  and  dusting  is  a  matter 
of  conjecture.  Reiser  and  Spennrath  {Handbook  of  Weaving)  state  that  the  acid 
in  the  wool  is  concentrated  at  the  most  to  only  5°  Be.  But  their  conclusions  are 
based  on  improper  chemical  assumptions.  There  is  every  reason  to  believe  that  the 
acid  is  present  in  a  rather  highly  concentrated  form. 


190 


RECLAIMED   WOOL  AND   SHODDY 


Sometimes  the  neutralising  process  is  carried  on  by  rinsing  the  wool 
for  half  an  hour  in  cold  water,  then  extracting  and  afterwards  immersing 
in  the  soda  solution.  It  is  not  clear  what  advantage  is  gained  by  this 
method.  Possibly  the  object  is  to  economise  in  the  use  of  soda.  This, 
however,  is  a  mistake,  because,  as  already  stated,  sulfuric  acid  is  not 
removed  from  carbonised  wool  by  rinsing  it  in  water.  Warnings  appear 
in  technical  literature  in  regard  to  the  rinsing  in  water.  It  is  stated  that 
drops  of  water  falling  on  a  piece  of  carbonised  goods  that  has  not  been 
neutralised  will  cause  a  tender  spot  in  some  cases,  and  may  result  in  a  hole. 

The  wool  in  which  the  acid  has  been  completely  neutralised  must  now 
be  treated  to  remove  all  traces  of  glaubersalt  or  free  soda  remaining  on 
the  fiber.  This  is  done  by  re- 
peated rinsing  in  clean  water  in 
the  rinsing  bowl  of  an  ordinary 
scouring  machine  or  in  a  special 
rinsing  machine  (see  Fig.  80). 
The  wool  is  rinsed  in  the  clean 
water  that  enters  the  bowl,  and 
the  soda-laden  water  passes 
through  the  perforations  in  the 
false  bottom.  This  rinsing  com- 
pletes the  carbonising  process. 


^/^^f'^/^pm-^PZ^;:'^^^/, 


The  wool  is  dried  at  a  moderate  Fig.  80. — Special  Rinsing  Machine  for  Carbonised 
temperature,  and  is  then  ready  Wool, 

for  manufacture  into  yarn. 

8.  Gas  Process  with  Hydrochloric  Acid. — The  solution  of  hydro- 
chloric acid  gas  in  water,  which  is  known  commercially  as  hydrochloric  or 
muriatic  acid,  is  not  suited  for  carbonising  purposes.  The  dilute  solution 
of  muriatic  acid  when  heated  exerts  more  injurious  effect  on  the  wool 
fiber  than  does  dilute  sulfuric  acid.  The  effect  of  hydrochloric  acid  gas 
is  very  different.  The  use  of  this  gas  for  carbonising  was  first  mentioned 
in  a  German  patent  in  1877  issued  by  C.  F.  Gademann.  About  the  same 
time  Delamore  Fils  et  Cie.,  Elbeuf,  France,  carbonised  wool  with  hydro- 
chloric acid  gas.  From  the  chemical  standpoint  carbonising  with  hydro- 
chloric acid  gas  is  the  basis  for  carbonising  with  chloride  of  aluminium  or 
chloride  of  magnesium. 

The  process  and  apparatus  required  for  carbonising  with  this  gas  are 
very  different  fi'om  those  used  with  sulfuric  acid.  Soaking  in  the  acid, 
extracting,  and  preliminary  drying  are  dispensed  with.  Owing  to  the 
suffocating  character  of  the  gas  it  is  necessary  to  enclose  it  in  a  tight 
cylinder  from  which  the  air  has  been  partially  removed.  The  muriatic 
acid  gas  is  introduced  into  the  chamber,  and  the  temperature  raised  to 
210-230°.     At  the  end  of  two  hours  the  wool  is  carbonised.     Cold  air 


USE   OF   ALUMINIUM   CHLORIDE 


191 


is  then  introduced  into  the  chamber,  and  the  acid  fumes  removed  by 
a  fan. 

9.  Use  of  Aluminium  Chloride. — Carbonising  with  aluminium  chloride 
is  based  on  the  fact  that  this  salt  is  readily  dissociated  with  formation 
of  free  hydrochloric  acid,  consequently  the  action  is  very  similar  to  that 


Fig.  81. — Carbonising  Machine  for  Wool  Stock  or  Shoddy.     (C.  G.  Sargent.) 

of  the  preceding  method.  This  process  is  said  to  have  been  discovered 
by  Romain  Joly  at  Elbeuf  in  1874,  after  efforts  had  been  made  for  years 
to  find  some  process  of  carbonising  that  would  have  less  effect  on  the  wool 
fiber  than  had  the  sulfuric  acid  process.^ 

'  It  is  recorded,  however,  that  Stuart,  in  1872,  carbonised  wool  with  aluminium 
chloride;  he  received  a  British  patent  in  1869  for  a  process  of  carbonising  wool  with 
a  solution  of  aluminium  sulfate  and  common  salt. 


192 


RECLAIMED   WOOL  AND   SHODDY 


Carbonising  with  aluminium  chloride  has  been  extensively  adopted, 
although  it  is  more  expensive  than  the  sulfuric  acid  or  hydrochloric  acid 
processes.  The  process  of  carbonising  with  this  reagent  is  similar  to  that 
of  carbonising  with  sulfuric  acid.  The  wool  is  immersed  in  a  7°  Be. 
solution  of  aluminium  chloride.  The  wool  and  pieces  are  left  in  the 
solution  for  one  hour,  then  extracted  and  dried,  after  which  the  temperature 


Fig.  82.— Carbonising  Duster  for  Wool  Stock  and  Shoddy.     (C.  G.  Sargent.) 


is  raised  to  the  carbonising  point.  The  pieces  can  be  dried  on  a  frame  or 
tenter-bars  before  carbonising.  While  it  is  necessary  to  heat  the  solution 
to  180°-212°  F.  when  using  sulfuric  acid,  the  wool  must  be  heated  to  280° 
when  chloride  of  aluminium  is  used,  this  temperature  resulting  in  a  separa- 
tion of  the  salt  into  aluminium  hydrate  and  hydrochloric  acid  gas.^ 

1  There  has  been  much  difference  of  opinion  as  to  the  carbonising  action  of  aluminium 
chloride.  Frezone  claims  that  aluminium  chloride  is  decomposed  at  high  temperatures, 
releasing  muriatic  acid,  which  is  the  real  carbonising  agent.     Joly,  on  the  other  hand, 


USE   OF  ALUMINIUM   CHLORIDE  193 

The  wool  fiber  is  not  affected  as  much  by  carbonising  with  chloride  of 
aluminium  as  with  sulfuric  acid.  This  is  only  natural,  as  muriatic  acid, 
according  to  the  general  opinion,  is  the  carbonising  agent,  and  comes  in 
contact  with  the  wool  fiber  in  the  form  of  a  gas;  also  because  of  presence 
of  alumina,  the  effect  of  the  acid  on  the  fiber  is  reduced. 

Wagner  has  given  as  his  opinion  that  the  alumina  with  the  hydrochloric 
acid  gas  serves  to  protect  the  color  against  injury.  This  explains  why 
carbonising  with  aluminium  chloride  has  so  slight  an  effect  on  the  colors. 
This  absence  of  injury  to  colors  proves  that  carbonising  with  aluminium 
chloride  produces  a  different  effect  from  carbonising  with  hydrochloric  acid, 
and  that  the  claim  is  unfounded  that  carbonising  with  aluminium  chloride 
is  the  same  as  with  hydrochloric  acid.  Breinl  and  Hanofsky  have  shown 
that  a  decomposition  of  the  aluminium  chloride  does  not  take  place  on 
the  fiber.^     This  conclusion  is  undoubtedly  correct,  as  the  alumina  can  be 

claims  that  the  aluminium  chloride  is  the  carbonising  agent,  this  being  shown  by  the 
fact  that  free  muriatic  acid  injures  fugitive  colors,  a  result  which  does  not  take  place 
when  carbonising  with  aluminium  chloride.  The  general  opinion  now  is  that  in 
carbonising  with  aluminium  chloride  the  carbonising  agent  is  free  hydrochloric  acid. 
There  is  a  difference  of  opinion,  however,  regarding  decomposition  of  the  compovmd. 
Most  authorities  state  the  chemical  action  as  follows: 

AI2CI6+6H2O  =6HCl+Al2(OH)6. 

Georgievics  claims  that  oxychloride  of  aluminium  is  left  on  the  fiber  as  a  result  of 
the  partial  decomposition  of  the  aluminium  chloride.  He  states  that  only  four-fifths  of 
the  chlorine  is  converted  into  hydrochloric  acid,  the  remainder  being  left  on  the  fiber  in 
the  form  of  oxychloride.  This  view,  however,  has  not  been  substantiated.  It  is  possible 
that  both  contentions  are  sound.  The  decomposition  begins  at  230°  F.  and  ends  at 
266°  F.,  and  it  is  conceivable  that  at  230°  F.,  and  somewhat  above  that  temperature, 
a  basic  aluminium  chloride  is  formed  according  to  the  following: 

AI2CI6+3H2O  =  3HCl+Al2Cl3(OH)3, 

and  that  only  when  a  temperature  of  257°  to  266°  F.  is  reached  does  the  following 
change  take  place: 

Al2Cl3(OH)3+3H20  =3HCl+Al2(OH)c. 

The  belief  that  the  decomposition  is  divided  into  two  phases  is  strengthened  by 
the  fact  that  aluminium  chloride  remains  on  the  fiber  in  the  form  of  an  anhydrous 
salt,  which  is  evaporated  and  decomposed  by  slowly  raising  the  temperature  above 
212°  F.,  and  that  decomposition  begins  only  at  230°  F.  Meyer  states  that  carbonising 
by  the  direct  action  of  the  aluminium  chloride  can  take  place  only  when  a  compound 
remains  on  the  fiber  in  an  anhydrous  state.  "As  chloride  of  aluminium  when  its  water 
content  is  evaporated  decomposes  into  alumina  and  muriatic  acid,  this  decomposition 
may  take  place  also  during  the  carbonising  process.  In  that  case  the  alumina  must 
become  fixed  on  the  fiber,  while  the  liberated  muriatic  acid  gas  must  have  the  same 
injurious  effect  on  the  colors  as  results  from  the  older  method  of  using  the  acid.  The 
strong  affinity  of  the  wool  fiber  for  alumina  makes  it  probable  that  such  a  decom- 
position would  be  promoted  by  the  presence  of  the  wool." 

>  There  are  certain  cases  in  which  carbonising  with  aluminium  chloride  exhibits 
the  same  effects  as  carbonising  with  acid.     Breinl  and  Hanofsky  state  that  these 


194  RECLAIMED   WOOL  AND   SHODDY 

rinsed  from  the  wool  with  water,  showing  that  the  alumina  is  not  fixed  on 
the  fiber. 

10.  Use  of  Magnesium  Chloride. — This  salt  is  somewhat  similar  to 
aluminimn  chloride  in  being  rather  easily  dissociated  on  heating  with 
liberation  of  free  hydrochloric  acid.  According  to  Ganswindt  carbonising 
with  chloride  of  magnesium  was  first  mentioned  in  a  patent  obtained  by 
A.  Frank  of  Charlottenburg,  in  1877.  Frank  stated  that  the  use  of  this 
material  for  carbonising  was  possible  by  reason  of  its  decomposition  into 
hydrochloric  acid  and  magnesia.^  He  recommended  that  the  chloride 
solution  be  made  up  at  5°  or  6°  Be.,  but  later  experience  has  shown  that 
this  strength  is  too  low  and  that  better  results  are  obtained  at  9°  or 
even  13°  Be. 

The  material  to  be  carbonised  is  impregnated  with  the  solution,  dried, 
and  then  exposed  to  a  high  temperature  at  which  the  vegetable  matter  is 
carbonised.  The  decomposition  of  the  magnesium  chloride  is  similar  to 
that  of  aluminium  chloride  and  requires  a  high  temperature.  Aluminium 
chloride  can  be  decomposed  at  200°  to  250°  F.,  while  magnesium  chloride 
requires  250°  to  300°  F.     The  goods  must  be  free  from  soap  and  fatty 

conditions  are  found  when  the  wool,  after  being  soaked  in  a  solution  of  aluminium 
chloride  is  not  dried  sufficiently  or  is  sprinkled  with  water  before  the  temperature  is 
raised  to  250°  F.  This  interesting  fact  proves  that  before  the  carbonising  action 
begins,  the  solution  of  aluminium  chloride  must  be  at  a  certain  concentration,  which 
results  from  the  preliminary  drying.  Very  little  is  known  regarding  the  necessary 
degree  of  concentration.  It  happens  that  a  solution  standing  at  7°  Be.  contains  by 
weight  7  percent  of  anhydrous  aluminium  chloride  and  93  percent  of  water.  In  order 
to  decompose  this  7  percent  into  hydrochloric  acid  and  alumina  21  percent  of  water 
is  necessary.  This  concentration  corresponds  to  a  25  percent  solution  of  aluminium 
chloride  standing  at  24°  Be. 

1  Frank  gives  the  following  formulae  for  the  chemical  action : 

MgCl2+  H20  =  MgO+2HCl; 
or 

MgCl2+2H20  =  Mg(OH)2+2HCl. 

It  is  doubtful,  however,  whether  the  separation  takes  place  according  to  these 
formulae.  Such  a  separation  would  require  a  temperature  higher  than  the  wool  fiber 
could  stand.  At  a  temperature  of  from  270°  to  290°  F.  magnesium  chloride  parts 
with  only  about  half  of  its  chlorine  in  the  form  of  hydrochloric  acid,  the  residue  not 
magnesia,  but  a  basic  chloride  of  magnesium  or  oxychloride,  according  to  this  formula: 

MgCl2+H20  =  Mg(OH)Cl+HCl. 

Whether  the  residue  is  solely  a  basic  chloride  of  magnesium  or  an  oxychloride 
remains  uncertain.  The  latter  is  possible,  because  magnesium  chloride  readily  changes 
to  oxychloride.  From  what  has  been  said  it  is  also  apparent  that  when  carbonising 
with  magnesivim  chloride,  what  remains  on  the  fiber  is  not  magnesia  or  magnesium 
hydroxide,  but  is  cither  a  basic  chloride  or  an  oxychloride.  This  is  an  important  point, 
because  the  formation  of  magnesia  or  magnesium  hydroxide  woiild  not  be  withodt 
influence  on  the  wool.  The  alkalinity  of  this  substance  is  so  great  that  it  would  have 
great  influence  on  many  colors. 


COMPARISON  OF  CARBONISING  METHODS  195 

materials  before  being  entered  into  the  solution,  otherwise  magnesium  soaps 
will  be  formed,  which  are  later  burnt  into  the  fiber  by  the  high  carbonising 
temperature.  The  vegetable  matter  begins  to  be  carbonised  at  245" 
to  265°  F.,  but  at  this  temperature  the  process  is  so  slow  that  it  has  been 
found  necessary  to  raise  the  temperature  from  280°  to  300°  F.  Above 
this  point  there  is  danger  of  injuring  the  fiber  and  making  it  yellow. 

Tests  by  Breinl  and  Hanofsky  show  that  the  carbonising  action  takes 
place  only  when  the  temperature  rises  above  270°  F.  A  temperature 
of  from  270°  to  300°  F.  is  sufficient.  Above  that  the  effect  on  the  wool  is 
questionable.  These  writers  assume  that  the  magnesium  chloride  separates 
readily  into  hydrochloric  acid  and  magnesia,  and  they  draw  this  conclusion 
from  the  alkaline  reaction  of  the  carbonised  goods.  On  the  other  hand,  it 
should  be  stated  that  the  basic  chloride  or  oxychloride  gives  a  basic  re- 
action, and  Georgievics  points  out  that  this  at  times  can  be  so  strong  as 
to  injure  the  wool  fiber. 

After  carbonising,  the  basic  chloride  of  magnesium  or  oxj'chloride  is 
removed  from  the  wool.  The  oxychloride  of  magnesium  is  more  or  less 
soluble  in  water,  the  solubility  decreasing  with  an  increase  in  the  alkalinity 
of  the  oxychloride.  The  less  alkaline  the  oxychloride,  the  more  necessary 
is  it  to  use  pure  water  for  rinsing.  The  more  alkaline  the  oxychloride,  the 
more  necessary  is  a  souring  with  dilute  hydrochloric  or  sulfuric  acid. 

11.  Comparison  of  Carbonising  Methods. — There  has  been  much 
discussion  in  the  technical  literature  as  to  the  pros  and  cons  of  the  various 
methods  of  carbonising,  taking  into  consideration  the  cost,  the  efficiency 
of  removal  of  the  cotton  or  other  vegetable  matter  and  the  liability  to 
injure  the  wool.  There  is  probably  no  question  but  that  the  sulfuric  acid 
process  is  the  lowest  in  cost,  and  under  proper  conditions  it  does  not 
appear  to  injure  the  fiber  or  the  machinery.  It  is  well  suited  to  raw  stock 
and  piece  goods.  Its  chief  disadvantage  is  its  bad  effect  on  colors,  though 
this  may  usually  be  overcome  by  neutralising  the  material  with  soda. 
Another  advantage  of  the  sulfuric  acid  process  is  the  low  temperature 
(180°  to  212°  F.)  at  which  the  carbonising  takes  place,  as  this  preserves 
the  wool  in  a  better  condition. 

The  hydrochloric  acid  gas  process,  though  without  doubt  somewhat 
more  costly  than  the  foregoing,  has  the  advantage  of  not  injuring  many 
colors  that  the  sulfuric  acid  process  destroys.  One  disadvantage  of  the 
hydrochloric  process  is  that  it  requires  certain  special  apparatus,  and 
furthermore  it  is  necessary  to  use  extreme  care  in  preventing  the  fumes 
of  the  acid  from  escaping  into  the  room  or  other  parts  of  the  mill,  as 
these  fumes  are  exceedingly  corrosive  and  will  damage  any  metal  parts 
with  which  they  come  in  contact.  When  efficiently  installed,  however, 
the  hydrochloric  acid  process  recommends  itself  stronglj^  to  the  carboniser, 
and  is  being  used  at  the  present  time  to  a  considerable  extent. 


196  RECLAIMED   WOOL  AND   SHODDY 

The  processes  involving  the  use  of  aluminium  chloride  of  magnesium 
chloride  do  but  veiy  httle  damage  to  the  colors  on  the  stock.  On  the  other 
hand  the  actual  carbonising  with  these  salts  does  not  take  place  until  a 
comparatively  high  temperature  has  been  reached,  therefore  the  process 
necessitates  a  larger  consumption  of  heat,  and  there  is  also  the  danger  of 
the  fiber  being  overheated  and  becoming  discolored,  which  of  course  will 
also  affect  the  appearance  of  the  dyed  color.  Another  disadvantage  to 
consider  is  the  presence  of  the  metallic  oxychloride  or  hydroxide  in  the 
fiber.  The  chief  difference  between  carbonising  with  aluminium  chloride 
and  magnesium  chloride  is  that  the  reaction  of  the  treated  wool  in  the 
first  case  is  acid  while  in  the  second  case  it  is  basic;  and  it  must  be  borne 
in  mind  that  whereas  aluminium  chloride  will  not  appreciably  affect  colors 
that  are  ordinarily  considered  as  sensitive  to  acids,  yet  magnesium  chloride 
carbonising  (owing  to  the  residue  of  basic  magnesium  salt  left  in  the  fiber) 
will  injure  many  colors  that  are  sensitive  to  alkalies.  Such  changes  in 
tone,  however,  may  usually  be  rectified  by  a  treatment  with  dilute  acid 
in  the  rinsing  waters. 

In  former  years  it  was  thought  that  the  carbonising  process  made  the 
wool  fiber  harsh  and  brittle  and  seriously  affected  its  spinning  qualities, 
therefore,  wool  in  the  stock  was  seldom  carbonised  if  such  a  process  could 
be  avoided.  It  has  been  shown,  however,  that  by  properly  conducting  the 
modern  methods  of  carbonising  the  wool  fiber  does  not  become  either 
harsh  or  brittle  and  loses  none  of  its  spinning  qualities.  In  consequence 
at  the  present  time  a  great  deal  of  even  the  best  classes  of  wool  is  car- 
bonised in  the  stock  before  either  carding  of  spinning,  it  being  considered 
that  this  procedure  will  give  a  better  finished  fabric  in  the  long  run  than 
would  be  obtained  by  putting  off  the  carbonising  process  until  after  the 
pieces  were  woven  and  dyed.  This  also  lays  to  rest  the  rather  popular 
idea  that  the  carbonising  process  in  the  preparation  of  extract  shoddies 
does  great  injury  to  the  fiber  and  therefore  that  such  wool  is  far  lower  in 
value  than  other  forms  of  wool.  Extract  wools  are  no  more  injured 
relatively  by  the  carbonising  process  than  are  fleece  wools,  and  therefore 
the  acid  treatment  for  the  preparation  of  shoddy  cannot  be  regarded 
as  an  injurious  process. 

12.  Flocks. — These  are  the  short  waste  wool  fibers  recovered  in  several 
of  the  manufacturing  processes  through  which  cloth  must  pass  in  finishing. 
There  are  two  distinct  classes  of  flocks:  (1)  those  resulting  from  scouring, 
fulling,  raising,  brushing,  and  shearing  of  woolen  or  worsted  fabrics;^ 

1  As  an  interestinci;  point  in  the  "virgin"  wool  vs.  shoddy  controversy  in  the 
various  "Truth-in-Fabric"  bills,  it  must  be  recognised  that  wool  flocks  of  the  first 
class  are  "virgin"  wool  and  could  be  so  labeled  in  garments  without  deviating  from 
the  technical  truth.  They  are  just  as  much  "virgin"  wool  as  carded  or  combed  wools, 
and  yet  they  form  one  of  the  lowest  grade  of  "substitutes"  to  be  used  in  the  prepara- 
tion of  woolen  fabrics. 


OTHER  FORMS  OF  RECLAIMED  WOOL  197 

(2)  those  resulting  from  rag  grinding  and  tearing  in  the  preparation  of 
reclaimed  wool.  The  first  class  is  known  as  finisher's  flocks,  while  the 
second  is  known  as  rag  flocks.  Flocks  are  sorted  for  the  trade  into  a 
number  of  different  grades,  depending  on  their  origin,  quality,  and  color. 
Flocks  from  waste  must  not  be  confused  with  the  flocks  made  from  rags 
and  used  for  the  stuffing  of  mattresses  and  bedding.  These  are  known 
as  manufactured  flocks  as  they  are  made  in  this  form  intentionally  and 
are  not  recovered  as  waste  from  other  operations. 

The  best  class  of  flocks,  which  have  sufficient  length  of  fiber  for  purposes 
of  spinning,  are  blended  with  better  grades  of  wool  and  spun  into  cheap 
low-grade  yarns.  The  shorter  flocks,  which  are  not  suitable  for  spinning, 
are  employed  as  impregnating  or  filling  material  in  the  felting  or  fulling 
of  woolen  goods.  The  lowest  grades  of  flocks  are  used  for  the  making  of 
embossed  wall-papers.  In  the  filling  of  fabrics  with  flocks  in  fulling,  the 
cloth  may  be  increased  40  percent  in  weight  by  flocking.  The  flocks  are 
applied  at  intervals  during  the  soaping  of  the  goods  in  the  fulling  machine. 
In  flocking  it  is  important  that  the  cloth  should  not  be  run  too  dry  or  the 
flocks  may  fail  to  be  thoroughly  felted  into  the  goods. 

13.  Other  Forms  of  Reclaimed  Wool. — Besides  these  well-known 
varieties  of  recovered  wool  there  are  a  number  of  others  to  be  met  with  in 
commerce,  such  as  Thibet  wool,  which  is  usually  obtained  from  light-weight 
cloth  clippings  and  waste.  Cosmos  fiber  is  a  very  low-grade  material, 
usually  containing  no  wool  at  all,  being  made  by  converting  flax,  jute,  and 
hemp  fabrics  back  to  the  fiber.  Peat  fiber  is  a  product  obtained  from 
partially  decomposed  peat.  It  is  mixed  with  wool  for  yarns  to  be  used 
in  the  manufacture  of  horse-cloths,  mats,  etc.  Wood-wool  is  a  somewhat 
similar  product  obtained  from  the  long  bleached  fibers  of  wood. 

Noils  may  be  considered  in  a  certain  sense  as  a  form  of  reclaimed  wool, 
or  waste,  but  strictly  speaking  this  class  of  fiber  is  simply  the  short  material 
separated  by  combing  from  the  long  stapled  wool  and  is  not  really  a 
recovered  waste.  Noils  cover  a  wide  range  of  material  and  qualities, 
however;  the  lower  grades  of  noils  are  often  classed  in  with  reclaimed 
wool  or  shoddies,  while  the  better  grades  of  noils  are  to  be  considered  as 
fleece  wool  useful  as  material  for  the  spinning  of  woolen  yarns.  The  latter 
class  of  noils  has  already  been  discussed  to  some  extent  in  the  consideration 
of  the  wool  fiber,  and  has  been  classed  under  botany,  merino,  and  cross- 
bred noils. 

Noils  are  also  obtained  from  other  varieties  of  hair  fibers  than  the  true 
wool  of  the  sheep.  Alpaca  noils  are  of  good  quality,  having  a  fair  staple, 
and  being  open,  uniform  and  straight.  They  are  adapted  for  blending 
with  good  shoddy.  They  are  used  to  develop  the  so-called  "  hairy  "  yarn 
used  in  certain  classes  of  fabrics.  Mohair  noils  are  used  to  blend  with  the 
better  grades  of  shoddy  and  certain  cross-bred  and  cheviot  wools.     Cash- 


198  RECLAIMED   WOOL  AND   SHODDY 

mere  noils  are  short  in  staple  but  extremely  soft  and  are  mixed  with  fine 
wools.     Camel-hair  noils  are  also  used. 

There  is  another  form  of  reclaimed  wool  known  as  pulled  yarn  waste. 
It  is  a  valuable  by-product  obtained  from  the  waste  yarn  in  spinning, 
weaving,  yarn  winding,  etc.  Like  noils,  this  class  of  material  is  a  "  pure  " 
wool  product  and  furnishes  a  very  good  grade  of  fiber.  The  yarns  are 
fiberised  by  treatment  in  a  yarn-pulling  machine.  Depending,  of  course, 
on  the  character  and  nature  of  the  original  yarn,  there  will  be  many 
grades  and  qualities  of  pulled  yarn  waste.  The  garnett  machine  is  prin- 
cipally used  in  recovering  the  fiber  from  yarns  and  the  product  is  often 
known  as  "  garnetted  "  waste. 

14.  Economic  Aspect  of  Shoddy. — A  good  deal  can  be  said  in  favor  of 
shoddy  and  its  discriminating  use  in  the  manufacture  of  woolen  goods. 
The  word,  however,  has  fallen  into  rather  bad  repute  and  has  come  to 
designate  material  that  is  imperfect  and  of  low  quality.  There  have 
been  numerous  attempts  made  to  pass  legislation  requiring  the  proper 
and  distinctive  branding  of  fabrics  containing  shoddy.  As  it  is  probable 
that  about  one-quarter  of  the  amount  of  wool  manufactured  into  woolen 
fabrics  at  the  present  day  consists  of  shoddy,  the  question  is  a  large  and 
comprehensive  one.  The  aversion  toward  shoddy,  however,  is  in  general 
rather  unwarranted,  and  the  whole  subject  should  be  discussed  on  the 
basis  of  the  quality  of  the  fiber  irrespective  of  whether  it  is  fleece  wool  or 
recovered  wool.  It  has  already  been  pointed  out  in  the  consideration  of 
wool  that  the  fleece  of  the  sheep  consists  of  widely  varying  qualities  of 
fiber,  some  being  of  very  low  grade,  imperfect  in  structure,  coarse,  short, 
and  of  poor  quality.  There  is,  in  fact,  a  great  deal  of  high-grade  recovered 
wool  which  is  a  far  superior  grade  of  fiber  to  much  of  that  which  occurs 
in  the  fleece.  To  require  a  discrimination  between  recovered  wool  and 
fleece  (or  "  virgin  ")  wool  in  a  fabric,  with  the  purpose  of  discrediting 
the  former,  would  work  a  great  injustice,  for  under  such  circumstances 
fabrics  could  be  made  from  very  low-grade  fleece  wool  and  yet  be  classed 
as  of  ostensibly  better  character  than  fabrics  made  of  shoddy  or  partly 
of  shoddy.  The  use  of  low-grade  noils,  flocks,  and  the  like  would  give 
very  low  quality  cloth,  and  yet  such  cloth  could  be  labeled  ''  virgin  wool  " 
to  the  detriment  of  other  cloth  of  much  higher  quality  that  might  be  made 
of  better  class  fleece  wool  mixed  with  more  or  less  recovered  wool  or 
shoddy.  The  wearing  quality  and  other  characteristics  of  a  fabric  do 
not  depend  so  much  on  whether  it  is  made  from  fleece  wool  or  from  shoddy, 
but  on  whether  it  is  made  from  high-grade  or  low-grade  fiber. 

The  manufacture  of  shoddy  is  a  very  legitimate  and  useful  industry 
as  it  utilises  a  by-product  which  would  otherwise  be  wasted,  and  brings 
into  the  market  cheap  woolen  goods  for  those  who  otherwise  would  not 
be  able  to  wear  woolen  goods  at  all.     That  the  use  of  shoddy,  on  the  other 


EXAMINATION  OF  SHODDY 


199 


hand,  is  abused,  and  that  it  is  introduced  into  goods  that  are  misrepre- 
sented as  being  of  a  higher  quahty  than  they  really  are,  there  is  no  doubt; 
but  this  is  also  a  tendency  in  lines  of  manufacture  other  than  those  of 
the  woolen  trade. 

15.  Examination  of  Shoddy. — Woolen  fibers  consisting  of  shoddy 
sometimes  offer  a  characteristic  appearance  under  the  microscope,  suffi- 
cient, at  least,  to  distinguish  them  from  fibers  of  new  wool.  A  sample 
of  shoddy  generally  shows  the  presence  of  other  fibers  besides  wool,  and 
fibers  of  silk,  linen,  and  cotton  are  frequently  to  be  observed  (Fig,  83). 


Fig.  83. — Microscopic  Appearance  of  Shoddy,  Showing  the  Varied  Character  of  the 
Fibers.     (X350.)     (Micrograph  by  author.) 


Also,  the  colors  of  the  different  woolen  fibers  present  are  frequently  quite 
varied,  so  that  shoddy  usually  presents  a  multi-colored  appearance  under 
the  microscope.  A  very  striking  appearance,  also,  is  the  simultaneous 
occurrence  of  dyed  and  undyed  fibers;  the  diameters  of  the  fibers  will 
also  vary  between  large  limits,  the  variation  in  this  respect  being  much 
more  than  with  fleece  wool.  Some  samples  of  shoddy  will  also  show  a 
large  number  of  torn  and  broken  fibers,  and  usually  the  external  scales  are 
rougher  and  more  prominent. 

The  most  important  characteristic  of  shoddy,  which  may  be  employed 
in  detecting  its  presence,  is  the  presence  of  foreign  fibers.     Fabrics  made 


200  RECLAIMED  WOOL  AND  SHODDY 

from  pure  fleece  wool  generally  consist  of  only  one  kind  of  fiber,  and  high- 
grade  fabrics  which  are  made  from  the  best  kind  of  wool  should  also 
exhibit  a  rather  uniform  diameter  of  fiber.  In  no  case  should  such  a 
material  composed,  for  example,  of  merino  fleece  wool  show  the  presence 
of  coarse  hairy  fibers,  and  the  wool  going  into  any  high  grade  of  fabric 
should  be  so  selected  as  to  consist  of  only  one  kind  of  wool,  or  of  those  very 
closely  related  in  their  physical  characteristics. 

However,  the  different  wool  fibers  in  a  single  fieece  exhibit  wide  varia- 
tions, and  pure  fleece  wools  may  be  spun  together  which  show  a  con- 
siderable difference  in  the  general  microscopical  characteristics  of  the 
fiber  and  variations  in  diameter  of  the  fiber.  Although  they  may  deter- 
mine in  some  degree  the  value  of  a  fabric,  they  cannot  be  accepted  as  any 
sure  indication  of  the  presence  of  shoddy. 

It  is  said  that  the  thickness  of  wool  fiber  from  one  and  the  same  fleece 
may  vary  from  0.012  to  0.085  mm.,  and  it  is  also  worthy  of  note  that  even 
in  very  fine  wools  there  may  occur  many  instances  of  isolated  hairy  fibers. 
These  are  the  stiff-pointed  short  hairs  which  occur  in  certain  portions  of  the 
fleece,  especially  around  the  legs  and  neck.  Therefore  these  coarse  fibers, 
known  also  as  bristle  or  beard-hairs,  will  often  be  mixed  in  with  even  fine 
merino  wool,  and  they  can  scarcely  be  removed  in  the  ordinary  processes 
of  carding  and  combing. 

The  other  grades  of  wool,  such  as  the  domestic-territory  wools  in  mixed 
blood,  are  also  liable  to  contain  more  or  less  of  these  coarse  beard-hairs. 
Pure  fleece  wool  may  also  contain  a  small  amount  of  vegetable  fiber& 
derived  from  various  sources,  and  their  amount  may  easily  extend  to  about 
^  percent.  Even  small  traces  of  vegetable  fibers  in  fabrics  or  yarns  may  be 
recognised,  and  in  fact  their  quantity  determined,  by  boiling  a  weighed 
sample  of  the  material  in  a  5  percent  solution  of  caustic  soda  until  the 
wool  is  completely  dissolved,  then  filtering  through  a  fine-mesh  brass 
strainer  and  examining  the  residue  left  thereon.  In  this  manner  will  be 
found  any  vegetable  fibers  that  may  have  been  present  in  the  original 
sample,  as  these  will  be  unaffected  by  the  caustic  soda  solution,  and  by 
examination  under  the  microscope  it  will  be  easy  to  recognise  the  presence 
of  cotton,  linen,  or  jute. 

It  must  be  borne  in  mind,  however,  that  pure  wool  may  also  show  the 
presence  of  small  quantities  of  vegetable  fibers  at  times.  These  often 
arise  from  the  occurrence  of  burrs  (bristly  and  barbed  seeds  of  various 
plants)  in  the  original  fleece.  South  American  wools  are  especially  liable 
to  contain  such  burrs;  in  many  cases  these  are  incompletely  removed, 
and  may  ultimately  appear  even  in  the  woven  cloth.  This  frequently 
explains  the  existence  of  short  fibers  or  vascular  bundles  of  vegetable 
matter  in  cloth.  Isolated  fibers  of  woody  tissue  and  cotton  may  also 
accidently  creep  in  through  a  variety  of  causes.     According  to  Hohnel, 


EXAMINATION  OF  SHODDY  201 

samples  of  pure  wool  may  easily  contain  as  much  as  |  percent  of  vegetable 
fiber.  The  latter  authority  also  states  that  the  vegetable  fibers  of  shoddy, 
as  a  rule,  are  removed  by  carbonising;  hence  the  absence  of  cotton,  linen, 
etc.,  must  not  be  taken  as  a  criterion  to  distinguish  between  pure  wool 
and  shoddy.  To  purify  the  fabric  completely  it  is  necessary  to  carbonise 
the  cloth  so  that  the  vegetable  matter  may  be  decomposed,  and  then  the 
disintegrated  fiber  is  removed  by  beating  and  scouring.  In  case,  however, 
the  process  of  carbonisation  has  not  been  resorted  to,  the  presence  of 
vegetable  matter  may  be  detected  in  cloth  which  has  been  made  from 
pure  fleece  wool,  and  consequently  the  presence  of  this  material  does  not 
conclusively  point  to  the  fact  that  shoddy  has  been  employed  in  the 
preparation  of  the  cloth.  There  will  also  occasionally  be  found  other 
fibers  of  vegetable  origin  in  woolen  fabrics,  which  become  accidentally 
incorporated  with  the  yarn  or  fabric  through  a  variety  of  causes,  and  this 
is  especially  true  in  mills  engaged  in  the  manufacture  of  both  woolen  and 
cotton  materials  or  of  uniform  goods,  where  the  fly  from  the  cotton  rooms 
will  often  be  deposited  in  the  woolen  materials  in  process.  Furthermore, 
shoddy  material  made  from  fabrics  containing  both  wool  and  cotton  is 
nearly  always  subjected  to  the  carbonising  process,  whereby  all  the  vege- 
table fiber  is  removed,  and  consequently  we  may  have  goods  made  from 
shoddy  which  show  entire  absence  of  vegetable  fibers,  and  from  this  and 
the  foregoing  it  may  be  seen  that  the  presence  or  absence  in  small  quanti- 
ties of  these  vegetable  fibers  is  no  sure  criterion  as  to  whether  a  fabric 
consists  of  shoddy  or  not.  When  cotton  (always  dyed)  or  cosmos  fiber 
occurs  in  at  least  a  quantity  of  1  percent,  this  may  be  taken  as  an  indica- 
tion of  the  presence  of  shoddy,  as  pure  wool  would  scarcely  ever  happen 
to  be  adulterated  with  cotton;  this  only  happens  by  admixture  with  shoddy 
wool.  Undyed  cotton,  unless  present  in  considerable  amount,  cannot  be 
considered  as  a  suspicious  component. 

Sometimes,  however,  fleece  wool  is  mixed  with  cotton  for  the  spinning 
of  yarns  possessing  certain  properties,  as  in  the  making  of  hosiery  and 
underwear  yarns  even  of  the  better  qualities,  where  the  cotton  is  intro- 
duced for  the  purpose  of  reducing  the  shrinking  quality  of  the  wool,  and 
also  to  make  a  fabric  that  is  "  kinder  "  to  the  skin,  as  an  all-wool  under- 
garment is  usually  quite  irritating  when  worn  next  to  the  skin.  We  must 
also  consider  the  fact  that  in  much  cloth  we  may  have  a  cotton  or  filling 
crossed  with  wool  (or  worsted)  yarns,  and  the  latter  may  be  made 
entirely  from  fleece  wool.  In  such  cases  it  would  be  necessary  to  limit 
the  examination  to  the  individual  yarn  rather  than  to  extend  it  to  the 
fabric  as  a  whole. 

The  determination  of  the  length  of  staple  is  also  a  rather  unreliable 
indication  as  to  the  presence  of  shoddy,  for  there  are  varieties  of  shoddy 
wools  which  are  longer  in  staple  then  many  fleece  wools;  and  also  woven 


202  RECLAIMED   WOOL  AND   SHODDY 

goods,  though  composed  entirely  of  fleece  wool,  may  show  the  presence 
of  a  large  nmiiber  of  short  fibers  caused  by  the  shearing  of  the  surface  of 
the  cloth,  and  by  the  tearing  of  the  fibers  in  heavy  fulling.^ 

Where  woolen  cloth  has  been  impregnated  or  filled  with  short  fibers 
obtained  from  clippings,  such  may  usually  be  recognised  by  teasing  the 
sample  out  with  a  stiff-bristle  brush.  Good  cloth  should  not  yield  over 
f  percent  of  clipped  fibers  from  both  sides.  When  the  amount  of  such 
fibers  is  at  all  considerable,  they  may  be  used  as  serviceable  material  to 
test  microscopically  for  shoddy,  as  they  are  most  likely  to  be  made  up  of 
this  character  of  wool.  Attention,  however,  has  already  been  called  in  a 
previous  page  to  the  fact  that  these  short  flocks  may  consist  entirely  of 
fleece  (or  virgin)  wool  and  therefore  could  not  technically  be  considered 
as  shoddy. 

Fine  fleece  wools  hardly  ever  show  the  absence  of  epidermal  scales 
(though  this  is  frequently  the  case  with  coarse  wools) ;  hence,  if  examples 
of  such  fine  wools  are  found  showing  a  lack  of  epidermis,  it  may  usually  be 
taken  as  an  indication  of  shoddy. 

Fleece  wool  of  good  quality,  when  examined  under  the  microscope, 
nearly  always  exhibits  a  distinct  epidermis  consisting  of  variously  formed 
scales  which  appear  as  serrations  on  the  edge  of  the  fiber.  It  has  been 
thought  that  since  shoddy,  especially  the  lower  grades  of  this  fiber  included 
under  extract  wool  and  mungo,  has  been  subjected  to  severe  mechanical 

^  The  length  of  the  fiber  obtained  from  a  sample  of  fabric  can  only  be  taken  in 
certain  cases  as  indicating  the  presence  of  shoddy.  The  best  grades  of  shoddy  may 
have  a  longer  staple  of  fiber  than  some  inferior  grades  of  pure  fleece  wool.  This  in 
itself  is  a  disturbing  factor,  but  we  must  also  consider  another  feature  of  the  case. 
It  is  only  in  good  worsted  yarn  and  in  knit  goods  and  in  loosely  woven  unsheared  cloth 
that  the  wool  fiber  is  to  be  found  in  approximately  its  natural  length,  and  it  is  only 
in  worsted  yarn  and  in  knit  goods  that  it  is  at  all  possible  to  pull  out  from  the  sample 
the  separate  fibers  from  one  another  in  order  to  determine  their  true  length.  With 
material  made  of  carded  wool  this  operation  is  very  difficult,  and  in  many  cases  totally 
impossible.  In  full  woolen  fabrics  where  the  fibers  are  firmly  felted  together,  and 
especially  if  these  fabrics  have  been  sheared,  as  is  usually  the  case,  it  is  impossible  to 
separate  the  individual  fibers  in  any  sample  so  as  to  obtain  a  just  estimate  of  their 
natural  length,  as  all  the  fibers  taken  out  of  the  sample  for  examination  will  be  broken. 
Also,  due  to  the  shearing,  a  great  number  of  these  fibers  will  be  cut,  and  when  the 
fabric  is  disintegrated  for  purposes  of  examination,  a  large  quantity  of  short,  broken, 
and  cut  fibers  will  be  obtained,  it  making  no  difference  whether  such  fibers  were 
originally  obtained  from  pure  fleece  wool  or  from  shoddy.  It  also  frequently  happens 
that  in  heavily  fulled  goods  the  shearings  or  short-cut  fibers  from  other  cloths  are 
fulled  into  the  fabric  under  examination  in  order  to  increase  the  body  and  weight  of 
the  latter.  Consequently,  such  fabrics  may  often  contain  very  short  fibers,  although 
these  cannot  be  properly  classified  as  shoddy  wool.  It  is  also  to  be  remarked  that 
accurate  microscopic  determinations  of  the  length  of  a  large  number  of  individual 
fibers  is  both  difficult  and  time-consuming.  From  these  considerations  it  may  readily 
be  understood  that  the;  determination  of  the  length  of  fibers  taken  from  a  sample  of 
fabric  cannot  be  relied  upon  to  any  great  extent  to  ascertain  the  presence  of  shoddy. 


EXAMINATION  OF  SHODDY 


203 


and  probably  chemical  treatments,  the  epidermal  scales  would  be  more  or 
less  removed  from  the  surface  of  the  fiber,  and  consequently  that  such  wools 
would  show  a  large  number  of  individual  fibers  and  incomplete  epidermis. 
To  a  certain  degree  this  is  true,  but  it  is  also  a  fact  that  many  grades  of 
pure  fleece  wool  will  also  show  quite  a  number  of  fibers  having  a  lack  of 
proper  epidermal  scales. 

Hohnel  calls  attention  to  the  fact  that  the  following  conditions 
previous  to  the  manufacturing  process  itself  have  considerable  influence  on 
the  good  structure  and 
integrity  of  the  wool 
fiber :  Badly  cut  staple, 
lack  of  attention  in 
raising  the  sheep,  poor 
pasturage,  sickness  of 
the  animal,  the  action 
of  urine,  snow,  rain, 
dust,  etc.,  packing  the 
wool  in  a  moist  con- 
dition, rapid  and  fre- 
quent changes  of  mois- 
ture and  temperature, 
the  use  of  too  hot  or 
too  alkaline  baths  in 
scouring,  scouring 
with  bad  detergents, 
etc.  These  influences 
may  lead  to  the  par- 
tial removal  of  the 
epidermis,  and  to  the 
softening  and  breaking 

of  the  ends  of  the  fiber.^  There  must  also  be  considered  the  influence  of 
willowing,  carding,  combing,  spinning,  weaving,  gigging,  fulling,  acidi- 
fying, washing,  shearing,  pressing,  etc.,  from  which  it  is  easy  to  under- 
stand why  even  fibers  of  fleece  wool  may  show  the  entire  absence  of 
epidermis.     Hohnel  also  criticises  other  alleged  characteristics  of  shoddy, 

^  This  is  especially  true  when  dealing  with  materials  made  from  the  longer  and 
coarser  grades  of  wool,  for  the  finer  merino  wools  are  more  plentifully  supplied  with  a 
protective  layer  of  wool  fat,  and  consequently  the  epidermal  scales  therein  are  more 
perfectly  protected  from  injury,  and  will  not  show  peculiarity  of  absence  of  epidermis 
in  any  noticeable  degree.  Also,  the  merino  sheep  is  more  carefully  cultivated  and 
cared  for,  and  this  has  much  to  do  with  the  complete  development  and  preservation  of 
the  fleece.  In  addition  to  this,  the  fine  merino  has  a  fiber  which  is  soft  and  pliable, 
and  consequently  is  not  so  easily  injured  as  the  stiffer  and  coarser  fibers  of  the  lower- 
grade  wools. 


Fig.  84. — Fibers  from  Shoddy  Showing  Tom  and  Raveled 

Ends. 


204 


RECLAIMED  WOOL  AND  SHCDDY 


such  as  torn  places  in  the  fiber,  unevenness  in  diameter,  etc.,  claiming 
that  these  can  hardly  be  taken  as  an  indication  of  shoddy  because  such 
marks  are  often  regularly  present  in  many  fleece  wools.  Most  samples 
of  shoddy,  in  fact,  show  scarcely  any  structural  differences  from  ordi- 
nary fleece  wool. 

It  is  often  impossible  to  determine  by  chemical  or  physical  examination 
if  a  sample  of  woven  cloth  contains  shoddy  or  pure  fleece  wool  only.  There 
are  many  forms  of  shoddy  (remanufactured  fiber)  which  are  composed  of 
wool  fibers  of  excellent  quality ;  such,  for  instance,  as  the  shoddy  obtained 
from  knit-goods,  or  from  tailors'  clippings  of  loosely  woven  fabrics.  It  is 
possible,  in  fact,  to  have  a  fabric  composed  entirely  of  shoddy  to  exhibit  a 

better  quality  of  fiber  on  ex- 
amination than  a  fabric  which 
may  be  composed  of  pure 
(though  inferior)  fleece  wool. 
It  must  also  be  borne  in  mind 
that  when  a  fabric  is  un- 
raveled and  teased  apart  so 
that  an  examination  of  the 
fibers  may  be  made,  the 
fibers  so  obtained  in  reality 
constitute  a  form  of  shoddy, 
having  been  previously  sub- 
jected to  the  various  opera- 
tions of  manufacture .  Where- 
as it  is  quite  possible  to 
definitely  decide  whether  a 
sample  of  loose  wool  (or  even  yarn)  contains  shoddy  or  not,  in  very 
many  cases  it  would  be  impossible  to  make  such  a  statement  regarding  a 
piece  of  woven  cloth  from  an  analysis  or  examination  of  the  latter.  After 
all,  the  question  as  to  the  use  of  shoddy  in  woolen  fabrics  resolves  itself 
into  a  question  as  to  the  quality  of  the  fiber,  irrespective  of  the  fact  as  to 
whether  the  fiber  was  derived  first  hand  from  the  fleece  or  from  some 
other  source  of  manufactured  material.^ 

The  ends  of  shoddy  fibers,  however,  usually  present  a  torn  appearance ; 
at  least  there  is  a  great  predominance  of  such  fibers  in  shoddy,  whereas  in 

1  From  all  these  considerations  it  may  readily  be  understood  that  the  exact  deter- 
mination of  the  presence  of  shoddy  in  fabrics,  even  by  employing  the  most  skillful 
methods  of  scientific  investigations,  is  a  very  difficult  matter,  and  it  is  rather  foolhardy 
for  anyone  not  acquainted  with  the  conditions  of  the  problem  to  attempt  to  state 
that  shoddy  may  be  definitely  found  in  fabrics,  and  consequently  it  is  an  easy  matter 
to  regulate  the  use  of  shoddy  therein.  In  a  great  many  cases  the  only  person  who 
would  be  able  to  state  whether  shoddy  had  been  used  in  a  specific  sample  of  cloth 
or  not  would  be  the  manufacturer  who  made  the  cloth. 


Fig.  85. — Shoddy  from  Dyed  Worsted  Clips. 


EXAMINATION  OF  SHODDY 


205 


fleece  wool  this  appearance  is  seldom  to  be  observed,  the  end  of  the  fiber 
being  cut  off  sharply.  The  appearance  of  the  torn  fibers  may  be  easily 
observed  under  the  microscope;  the  epidermis  being  entirely  torn  away, 
as  well  as  the  marrow  which  is  sometimes  present,  while  the  fibrous  cortical 
layer  is  frayed  out  like  the  end  of 
a  brush.  This  appearance  can 
usually  be  re»dered  more  distinct 
by  previously  soaking  the  fibers 
in  hydrochloric  acid  (Fig.  84). 
Sheared  fibers  are  recognised  by 
being  very  short  and  by  having 
both  ends  sharply  cut  off. 

The  color  of  the  fibers  is  also 
a  characteristic  appearance  of 
shoddy,  as  the  majority  of  shoddy 
is  made  up  of  variously  colored 
wools.  It  is  of  rare  occurrence 
that  rag-shoddy  possesses  a  single 
uniform  color.  Hence  if  a  sample  Yig.  86— Shoddy  from  Fine  Dyed  Worsted 
of  yarn,  possessing  a  single  aver-  Clips, 

age  color,  on  examination  reveals 

the  presence  of  variously  colored  fibers,  it  is  ahnost  a  positive  indica- 
tion of  shoddy.  In  this  connection  it  must  not  be  forgotten,  however, 
that  differently  colored  wools  are  frequently  mixed  together  previous 
to  spinning,  to  make  so-called  "  mixes."  As  a  rule,  however,  only  two 
to  three  colors  are  used  together;  therefore  a  purposely  mixed  yarn  of  this 

description  is  not  likely  to  be  con- 
founded with  a  shoddy  yarn  where 
intlividual  fibers  of  a  large  number  of 
colors  are  nearly  always  shown. 

The  examination  of  yarns  and  fab- 
rics made  from  shoddy  or  mixtures 
of  shoddy  with  fleece  wool,  is  one  of 
the  most  difficult  and  interesting  prob- 
lems for  the  textile  microscopist,  as 
Fig.  87.— Shoddy  from  Carbonised  Brown  it  requires  a  high  degree  of  skill  and 
Serge.  accuracy   coupled  with  long  experi- 

ence. The  differentiation  between 
shoddy  and  fleece  wool  fiber  is  a  most  delicate  and  difficult  one.  This 
is  due  to  the  fact  that  every  individual  fiber  cannot  be  definitely  recognised 
as  being  shoddy  or  fleece  wool,  and  a  single  microscopical  characteristic 
does  not  suffice  to  distinguish  shoddy  in  a  sample.  In  order  to  arrive  at 
any  just   estimate   as   to   the   presence   of    shoddy    it   is  necessary    to 


206 


RECLAIMED  WOOL  AND  SHODDY 


conduct    many     comparative    examinations     on    known    samples      of 
material. 

One  feature  of  shoddy  fibers,  which  has  been  put  forward  as  a  possible 
means  of  detecting  their  presence,  is  that  they  are  more  susceptible  to 
the  action  of  strong  solutions  of  caustic  soda  or  sulfuric  acid  than  fibers 
of  fleece  wool.  For  observing  the  behavior  of  the  fibers  in  this  connection, 
fibers  of  new  wool  and  those  of  shoddy  are  placed  side  by  side  on  an  object 
glass  and  a  drop  of  concentrated  sulfuric  acid  is  touched  to  them;  the 
time  required  for  the  attacking  of  the  fiber  and  the  structural  changes 
which  take  place  are  then  noted.  Schlesinger  has  made  a  number  of 
interesting  tests  in  this  connection,  and  shows  that  the  shoddy  fibers 
are  attacked  sooner  and  also  to  a  greater  extent  than  fleece  wool  fibers. 
The  following  table  shows  some  of  the  results  obtained: 


Color  Changes  in  Shoddy  Fibers. 


Time  Occupied  in  the  Decomposition 
of  the  Outer  Scales  of  the  Fibers. 


Green  to  yellow 

Brown  to  light  brown 

Violet  to  colorless 

Black  to  red 

Red  to  pale  red 

Blue  to  colorless 

Yellow  to  dingy  yellow . . .  . 

Pink  to  yellow 

Black  to  yellow 

Deep  green  to  gray 

Deep  yellow  to  pale  yellow 

Deep  brown  to  orange 

Light  green  to  colorless. . . . 
Light  gray  to  colorless .... 
Colorless 


Shoddy. 

Wool. 

Mins. 

Sees. 

Mins. 

Sees. 

3 

45 

4 

05 

3 

15 

4 

15 

3 

15 

2 

55 

2 

10 

4 

00 

45 

6 

05 

45 

1 

25 

30 

3 

45 

15 

2 

20 

05 

5 

10 

05 

50 

00 

45 

00 

15 

0 

45 

30 

0 

30 

10 

0 

15 

4 

30 

While  these  tests  of  Schlesinger  are  interesting  they  are  scarcely 
conclusive  in  enabling  one  to  definitely  determine  the  presence  or  absence 
of  shoddy  in  a  sample  of  woolen  fabric.  The  character  of  the  tests  is  so 
indefinite  that  even  in  the  hands  of  a  skillful  microscopist  they  cannot 
yield  very  accurate  results. 

L.  J.  Matos  {Textile  World)  gives  some  interesting  drawings  showing 
the  torn  and  corroded  appearance  of  certain  grades  of  shoddy  fibers  under 
the  microscope.     Figure  85  is  shoddy  made  from  new,  fine,  blue  worsted 


EXAMINATION   OF  SHODDY 


207 


clips.  A  careful  inspection  of  the  drawing  shows  the  great  variety  of 
broken  ends  of  fibers,  and  also  the  tendency  of  the  fibers  to  split  or  to  tear 
lengthwise.  There  are  also  shown  three  fibers  with  side  breaks,  which 
evidently  are  a  result  of  a  tearing  action 
of  the  shoddy  machine.  Figure  86  shows 
a  shoddy  made  from  new,  fine,  black 
worsted  clips,  and  here  again  we  clearly 
notice  their  peculiar  terminal  fractures 
where  the  fiber  has  been  pulled  asunder. 
One  of  the  fibers  has  a  number  of  "  spines  " 
projecting  from  it.  These  so-called  spines 
are  really  the  fiber  cells,  which  were  no 
doubt  loosened  by  the  tension  on  the  fibers 
in  the  machine.  It  should  be  noted  that 
both  Figs.  85  and  86  represent  new  wool  Yig.  88.— Shoddy  from  Carbonised 
that    has    been   simply   mechanically   re-  and  Stripped  Wool, 

duced  to  shoddy,  and  not  at  any  time  car- 
bonised.    Figure  87  is  a  shoddy  made  from  carbonised  brown  serge.    Here 
is  to  be  seen  what  indicates  the  brittle  character  of  the  fiber,  devoid  of 
its  elasticity.     The  breaks  of  the  fiber  are  seen  to  be  quite  abrupt.     Figure 
88  is  shoddy  made  from  brown  serge  that  has  been  carbonised  and  sub- 


FiG.  89. — Shoddy  from  Carbonised,  Stripped 
and  Dyed  Wool. 


Fig.  90. — Shoddy  from  Carbonised 
Wool  Dyed  Red. 


sequently  stripped.  The  abrupt  character  of  the  breaks  is  plainly 
noticeable,  while  at  the  same  time  the  fibrils  comprising  the  body  of  the 
wool  fiber  are  very  distinct.  Their  presence  may  be  due  to  the  chemical 
action  of  stripping.  Figure  89  shows  fibers  made  from  blue  serge  that 
had  been  first  carbonised,  then  stripped,  and  afterwards  dyed  green. 
Here  again  we  notice  the  tendency  to  break  longitudinally,  and  where 


208 


RECLAIMED  WOOL  AND  SHODDY 


a  terminal  break  occurs  the  fibrils  appear  distinctly.  Figure  90  is  shoddy 
from  the  same  batch  as  that  shown  in  Fig.  88,  except  that  it  has  been 
dyed  a  full  red.  In  this  figure  we  notice  that  one  of  the  fibers  has  been 
split  longitudinally,  while  the  other  three  fiber  terminals  show  break 
characteristics  that  indicate  the  brittleness  of  the  stock.  Figure  91  was 
originally  a  brown  serge  that  had  been  carbonised,  then  stripped,  after- 
wards dyed  a  deep  orange,  and  finally  garnetted.  A  great  majority  of  the 
breaks  of  fibers  in  this  sample  are  extremely  abrupt.  There  appear  to 
be  no  longitudinal  ruptures,  and  this  seems  to  indicate  little  or  no  elasticity. 


Fig.  91. — Shoddy  from  Wool  Carbonised, 
Stripped,  Dyed  and  Garnetted. 


Fig.  92.— Shoddy  from  Wool 
Knitgoods. 


Even  the  fibrils  do  not  show  plainly.  Figure  92  is  a  shoddy  made  from 
various  knit  goods  of  different  colors  that  were  first  carbonised,  then 
stripped,  and  afterwards  dyed  blue.  Some  of  the  rags  came  from  the 
dye-bath  a  purple  shade,  others  a  blue-slate,  some  distinctly  blue,  while 
others  were  quite  black.  The  garnetted  stock  has  a  pleasing  blue  shade, 
inclining  to  the  red.  Referring  to  the  figure,  the  fibers  seem  to  be 
mutilated  and  broken.  One  fiber  shows  a  rather  curious  side  abrasion,  a 
form  of  mutilation  that  appears  to  be  quite  common  in  this  lot  of  shoddy. 


CHAPTER  VIII 


MINOR  HAIR  FIBERS 


1.  The  Minor  Hair  Fibers. — Besides  the  fiber  obtained  from  the 
domestic  sheep,  there  are  large  quantities  of  hair  fibers  employed  in  the 
textile  industries  and  obtained  from  related  species  of  animals,  such  as 
goats,  camels,  etc.  As  these  are  all  more  or  less  utilised  in  conjunction 
with  wool  itself,  and  are  subjected  to  similar  operations  in  manufacturing, 
it  will  not  be  out  of  place  to  consider  them  at  this  point.  The  chief  among 
these  related  fibers  are  mohair,  cashmere,  alpaca,  cow-hair,  and  camel-hair. 

The  following  table  showing  the  comparison  of  the  various  minor  hair 
fibers  is  adapted  from  Barker: 


Mohair. 


Alpaca. 


Camel-hair. 


Cashmere. 


Length,  ins 9 

Strength Very  strong 

Luster iVery  high 

Color IWhite 


Fineness,  ins . . . 

Handle 

Form  of  staple . 
Uniformity .  .  .  . 
Uses 


1/700 

Fairly  soft 

Straight 

Uniform 

Dress  fabrics, 
linings,  up- 
holsteries 


12 
Fairly  strong 
High 
Vari-colored 

1/800 
Soft 
Straight 
Uniform 
Dress      fabrics, 
linings 


Fairly  strong 

Good 

Brownish 

1/800 
Soft 

Fairly  curly 
Fair 
Dress  fabrics 


Fairly  strong 

Good 

Brown  and  white 

1/12000 
Very  soft 
Fairl}^  curly 
Fair 

Shawls     and 
hosiery 


2.  Mohair. — This  fiber  is  obtained  from  the  Angora  goat  (Fig.  93), 
an  animal  which  appears  to  be  indigenous  to  western  Asia,  being  largely 
cultivated  in  Turkey  and  neighboring  provinces.^  The  fleece  is  com- 
posed of  very  long  fibers,  fine  in  staple,  and  with  little  or  no  curl.  The 
fiber  is  characterised  by  a  high  silky  luster.     Mohair  is  now  grown  to  a 

^  The  Angora  goat  is  a  species  descended  from  the  genus  Capra  ^gagrus,  the  claimed 
ancestor  of  all  Capra  Hiicus  or  domestic  goats,  inhabiting  the  hills  of  Southern  Europe 
and  Asia  Minor.  It  is  fairly  large,  and  during  the  warm  season  grows  a  short  woolly 
fur  of  a  grayish  brown  color;  this  in  winter  is  covered  with  a  larger  and  brighter  hair. 
There  is  no  record  of  the  early  domestication  of  this  goat,  but  it  doubtless  existed 
from  the  remotest  times  in  Asia  Minor,  and  has  for  ages  produced  hair  remarkable 
for  its  length,  luster  and  fineness. 

209 


210 


MINOR  HAIR   FIBERS 


considerable  extent  in  the  Western  States,  principally  Oregon,  California, 
and  Texas,  the  goats  having  originally  been  imported  from  Tm'key;  there 
is  also  a  large  quantity  of  mohair  grown  in  Cape  Colony.  The  principal 
mohair  clips  (1902)  are  as  follows: 

Turkey 8,500,000  lbs. 

Cape  Colony 7,500,000   ' ' 

United  States 1,250,000  " 

The  principal  use  of  mohair  is  for  the  manufacture  of  plushes,  braids, 
fancy  dress  fabrics,  felt  hats,  and  linings.     The  character  of  fabric  in 

which  it  may  be  em- 
ployed is  rather  limited 
on  account  of  the  harsh 
wiry  nature  of  the  mohair 
fiber,  and  the  fact  that  it 
will  not  felt  to  any  de- 
gree.^ 

Domestic  mohair 
(American)  has  only 
about  two-thirds  of  the 
value  of  the  foreign  fiber ; 
mohair  in  general  has 
quite  a  large  amount  of 
kempy  fiber  (which  will 
not  dye),  but  the  do- 
mestic variety  contains 
about  15  percent  more 
kemp  than  the  foreign, 
hence  the  lower  value 
of  the  former.  Another 
reason  for  this  lessened 


Pig.  93. — Angora  Goat. 


value  is  that  foreign  mohair  always  represents  a  full  year's  growth 
(the  fibers  being  9  to  12  ins,  in  length),  whereas  a  great  deal  of  domestic 
mohair  is  shorn  t\Aace  a  year.  This  is  especially  true  of  that  grown 
in  Texas;  the  hair  commences  to  fall  off  the  goats  in  that  district 
if  allowed  to  grow  for  the  full  year.  In  judging  of  the  quality  of 
mohair,  the  length  and  luster  are  of  more  value  than  the  fineness 
of  staple.     The  finest  grades  of  domestic  mohair  come  from  Texas,  the 

1  The  mohair  fiber  is  harder  and  stiffer,  though  more  elastic  than  wool,  and  it  is 
especially  useful  for  embossed  upholsteries  and  pile  fabrics;  its  luster  rivals  that  of 
silk  and  is  very  permanent  in  character.  Mohair  absorbs  less  moisture  than  wool, 
and  it  does  not  felt,  so  should  not  be  used  for  fulled  fabrics.  The  draping  properties 
of  mohair  fabrics  are  excellent,  and  on  account  of  its  high  luster  the  fiber  is  largely 
used  for  the  manufacture  of  braids. 


CLASSIFICATION  OF  MOHAIR  211 

fiber  from  Oregon  and  California  being  larger  and  coarser.  In  Oregon 
the  fleece  is  grown  for  a  full  year,  and  consequently  the  fiber  is  very  long. 
The  average  weight  of  the  fleece  from  Oregon  goats  is  4  lbs.  while  in  Texas 
it  is  only  2\  lbs.  Foreign  mohair  varies  much  in  quality,  depending 
upon  the  district  in  which  it  is  grown;  as  a  rule,  the  finer  varieties  are 
shorter  in  staple,  the  finest  being  about  9  ins.  in  length.  Foreign  mohair 
can  be  spun  to  as  high  a  count  as  60's,  whereas  the  finest  quality  of 
domestic  mohair  can  only  be  spun  to  as  high  as  40's.  The  coarsest  vari- 
eties of  mohair  are  used  in  carpets,  low-grade  woolen  fabrics,  and  blankets. 

In  its  manufacturing  processes  the  treatment  of  mohair  is  practically 
the  same  as  that  of  long  wool.  The  fleece  possesses  several  qualities; 
thus  an  average  fleece  would  have  36's  quality  from  neck,  40's  from 
shoulders,  36's  from  middle  of  sides  and  back,  32's  from  haunches,  and 
lower  qualities  of  28's  and  under  from  the  edges. 

The  term  mohair,  in  a  general  sense,  is  becoming  an  extensive  one. 
including  the  fiber  from  the  fleeces  of  goats  of  various  crosses  with  the  true 
Angora. 

3.  Classification  of  Mohair  .^According  to  E.  W.  Tetley  (Textile 
Manufacturer)  the  different  kinds  of  mohair  may  be  classified  under  the 
following  heads: 

Turkey  Mohair. — As  would  be  expected  from  the  native  home  of  the 
Angora  goat,  Turkey  mohair  is  of  the  very  best,  being  of  good  length,  excel- 
lent luster,  and  clear  color.^  It  is  only  reasonable  to  expect  that  it  will 
become  still  better  in  quality,  for  the  methods  employed  at  present  in 
breeding  and  rearing,  in  sorting,  classing,  and  packing,  leave  ample  room 
for  improvement  on  more  scientific  lines.  Different  goat  districts  supply 
different  classes  of  hair — i.e..  Angora,  Beybazar,  Castamboul,  and  Van 
(Fig.  94).     The  following  list  will  give  some  idea  of  their  characteristics: 

Fine  Districts. — Length,  6-7  in.;  luster  excellent,  color  very  clear,  handle  very  soft. 

Beybazar. — Length,  8-9  in.;  luster  very  good,  color  good,  handle  soft. 

Angora. — Length,  8-9  in.;  luster  very  good,  color  good,  handle  soft. 

Fair  Average.- — -Length,  8  in.;   luster  good,  color  fairly  good,  handle  fairly  soft. 

Castamboul. — Length,  8-10  in.;   luster  good,  color  fairly  good,  handle  fairly  soft. 

In  addition  to  these  standard  qualities  of  mohair,  there  are  various 
lower  grades  always  on  the  market — viz. :  Good  gray,  good  yellow  fleece, 
locks,  ordinary  yellows. 

'  Barker  states  that  the  quality  of  Turkey  mohair  is  not  what  it  once  was.  The 
deterioration  was  caused  by  crossing  with  the  common  Kurd  goat  resulting  from  an 
unexampled  demand  for  mohair  fiber  b.y  Europe  from  1820  to  about  1860.  The  Kurd 
goat  yields  only  a  long  coarse  kempy  hair,  mostly  used  for  tent  and  sackcloth.  Since 
1880,  however,  the  quality  of  Turkish  mohair  has  much  improved  by  breeding  back 
to  the  true  Angora  type. 


212  MINOR  HAIR   FIBERS 

Barker  gives  the  qualities  of  Turkey  mohair  as  follows : 


Length,  ins. 

Luster 

Fineness,  ins 

Handle 

Appearance. 

Cleanness.  .  , 
Uniformity. 


Turkey  Fine. 
Fine. 


6  to  7 
Very  lustrous 

1/800 
Very  soft 
Good    color, 
wavy,  clearly 
defined 
Very  clean 
Very  uniform 


Turkey  Fair, 
Average. 


6  to  8 
Fairly  so 

1/400 
Fairly  soft 
Fair   color, 
clearly 
fined  in  staple 
Fairly  clean 
Uniform 


not 
de- 


Turkey 
Beybazar. 


7§  to  9 
Lustrous 

1/600 
Soft 

Good     color, 
clearly        de- 
fined in  staple 
Fairly  clean 
Uniform 


Turkey 
Castamboul. 


8  to  10 
Very  lustrous 

1/600 
Very  soft 
Good    color, 
wavy,  clearly 
fined  in  staple 
Clean 
Uniform 


Fig.  94. — Mohair  from  Turkey.     (1)  Fine  districts;    (2)  Beybazar;    (3)  Angora;    (4) 
fair  average;   (5)  Castamboul.     {Text.  Mfr.) 

Van  Mohair,  drawn  from  the  district  of  that  name  in  Asia  Minor, 
is  dirty  and  very  dry,  though  it  scours  up  very  well,  and  is  specially  men- 
tioned in  the  British  Factory  Act  as  a  dangerous  wool,  being  more  liable 
than  other  mohair  to  contain  the  deadly  germs  of  anthrax.  In  fineness, 
Turkey  mohair  goes  up  to  about  50's  quality. 

Cape  Mohair. — In  spite  of  many  difficulties,  the  Angora  goat  was 
successfully  introduced  and  crossed  with  the  South  African  variety  to 
produce  a  breed  of  goats  growing  a  good  class  of  hair;  indeed,  mohair 
from  the  Cape  will  now  bear  comparison  with  the  best  Turkish  qualities, 
the  climate  and  general  conditions  being  very  suitable.^     The  color  of 

1  The  Cape  Colony  at  the  present  day  yields  about  one-half  the  world's  supply  of 
mohair,  and  the  flocks  amount  to  about  4,000,000  goats. 


CLASSIFICATION  OF   MOHAIR 


213 


Cape  mohair  is  not  generallj^  so  clear  as  Turkey  hair,  being  of  a  rather 
deeper  brown.  There  are  two  chps  a  year,  summer  growth  and  winter 
growth.     The  following  list  shows  the  principal  classes  (Fig.  95). 

Ca-pe  Kids. — I'he  first  shear  from  the  3'oung  goat,  equivalent  to  lamb's  wool.      Length, 

6-7  in.;  very  lustrous,  brownish  color,  and  very  soft. 
Cape  Firsts. — The  long  summer  growth.      Length,  8  ins.;   very  lustrous,  fairly  clear  in 

color,  and  soft. 
Cape  Winter. — The  shorter  winter  growth.      Length,  5  ms.;    good  luster,  fairly  clear 

color,  and  fairly  soft. 
Cape  Basuto. — A  class  of  hair  rather  stronger  and  coarser  than  Cape  firsts. 
Cape  Mixed. — A  class  of  hair  in  between  Cape  firsts  and  Cape  winter,  such  as  a  late 

clip,  or  a  mixture  of  the  two  clips. 
Thirds. — Equivalent  to  edges  of  a  long  wool  fleece.     Each  fleece  may  be  subdivided 

into  firsts,  seconds,  and  thirds,  according  to  fineness,  length  and  luster. 


Fig.  95. — Cape  Mohair  Samples.     (1)  Basuto;    (2)  mixed;    (3)  winter  hair;  (4)  Cape 
firsts;  (5)  Cape  kids.     {Text.  Mfr.) 

From  the  foregoing  it  will  be  seen  that  Cape  kids  are  the  most  valuable 
product,  on  account  of  their  extra  fineness,  and  because  the  supply  is  small. 
Cape  firsts  are  valuable  on  account  of  their  good  quality,  combined  with 
extra  length.  Cape  mohair,  in  fineness,  goes  up  to  about  the  same  quality 
number  as  Turkey  hair — viz.,  50's. 

According  to  Barker,  improvement  in  Cape  mohair  would  be  possible  if 
double  clipping  could  be  avoided.  Clipping  the  goat  twice  a  year  neces- 
sarily implies  a  shorter  staple.  It  is  claimed  that  the  double  clipping  is 
necessary  to  prevent  the  shedding  of  the  fleece.  The  fineness  of  fiber  of 
Cape  mohair  is  also  not  all  that  could  be  desired  and  there  is  a  large  pro- 
portion of  kemps.  These  defects  can  only  be  improved  by  careful  breeding 
and  cultivation.  The  uniformity  of  staple  is  not  as  good  as  that  of  Turkey 
mohair.  Barker  furnishes  the  following  properties  of  the  different  kinds 
of  Cape  mohair: 


214 


MINOR  HAIR  FIBERS 


Type. 

Length. 

Luster. 

Fineness. 

Handle. 

Appearance. 

Cleanness. 

Uniformity. 

Ins. 

Ins. 

Cape  Kid  . . . 

5  to  7 

Very  lustrous 

1/800 

Very  soft 

Yellowish  color, 
clearly  defined 
staple 

Clean 

Very  uni- 
form 

Cape  Firsts .  . 

6  to  8 

Very  lustrous 

1/600 

Soft 

Fair  color,  clearly 
defined  staple 

Fairly 
clean 

Fairly   uni- 
form 

Cape  Winter . 

5 

Fairly  lustrous 

1/600 

Fairly  soft 

Fair    color,    fairly 
defined  staple 

Fairly 
clean 

Fairly   uni- 
form 

Cape  Seconds 

5 

Fairly  lustrous 

1/600 

Fairly  soft 

Bluish  color,  kem- 
py,     fairly     de- 
fined staple 

Dirty 

Not  uni- 
form 

Cape  Mixed. . 

4  to  5 

Poor  in  luster 

Irregular, 
coarse 

Harsh 

Varied;    disorgan- 
ised   in    staple; 
strong    and 
"wiry" 

Dirty 

Not  uni- 
form 

American  Mohair. — Of  late  the  United  States  growers  have  much 
improved  the  breed  of  goats,  although  the  manufacturers  consider  both 
Turkey  and  Cape  mohair  to  be  worth  much  more  than  the  domestic 
types,  being  more  lustrous,  less  kempy,  and  possessing  superior  spinning 
qualities.  Half  the  total  of  the  United  States  clip,  and  the  best  quality 
hair,  comes  from  Texas,  the  rest  being  supplied  by  California,  Oregon, 
New  Mexico,  and  other  Western  States.  The  goats  are  clipped  twice  a 
year,  in  spring  and  fall,  owing  partly  to  climatic  conditions,  and  partly 
because  two  clips  of  six  months  bring  more  profit  than  one  of  twelve 
months. 

Australian  Mohair. — The  production  of  mohair  in  Australia  is  only 
slight,  and  it  is  unlikely  that  it  will  greatly  increase  for  a  long  time,  unless 
an  unexampled  demand  for  the  5ber  comes  about,  as  Australia  is  a  great 
wool-growing  country.  The  goat  is  useful  in  keeping  down  scrub,  and  in 
quality  its  hair  is  good,  being  of  the  class  of  a  Turkey  average. 

Mohair  Tops. — In  the  preparation  of  mohair  for  spinning  the  fibers  are 
combed  into  tops  somewhat  in  the  same  manner  as  long  stapled  wools. 
Oil  is  added  as  in  the  case  of  wool,  to  the  extent  of  about  2  percent,  and 
as  the  fiber  has  a  marked  tendency  to  fly  about,  the  oil  is  useful  in  keeping 
the  fibers  together.  Mohair  tops  are  not  usually  quoted  in  quality  num- 
bers, but  as  in  the  following  list.  The  diameters  of  the  fibers  of  each 
quality  are  the  average  of  a  large  number  of  tests,  and  enable  their  fineness 
to  be  compared  with  the  wool  tops.  The  fine  white  mohair  gives  measure- 
ments corresponding  to  a  56's  quality  wool  top. 


Mohair  fine  white  top 

' '       good  medium  white  top 

* '       medium  white  top 

i'       ordinary  white  top .... 


Diameter  in  Inches. 


0.00102 

1/976 

0.00133 

1/754 

0.00160 

1/626 

0.00188 

1/535 

MICROSCOPY  OF  MOHAIR  215 

Testing  Mohair  Tops  for  Quality  and  Uniformity. — As  in  the  case  of 
wool  tops,  judging  quality  is  largely  a  question  of  practice,  though  of  course 
there  is  not  the  wide  range  in  mohair  tops  that  has  to  be  dealt  with  in 
wool  tops.  It  may  be  noted  here  that  English  luster  wool  is  often  mixed 
with  mohair  for  medium  and  lower  qualities.  Mohair,  especially  the  finer 
sort,  is  uniform  in  length,  but  "  draws  "may  be  made  from  a  mohair  top 
of  the  longest  to  the  shortest  fibers,  exactly  as  when  testing  a  wool  top  for 
uniformity. 

Mohair  noils  are  the  short  fibers  separated  in  the  combing  of  mohair. 

4.  Microscopy  of  Mohair. — Microscopically,  the  mohair  fiber  is  pos- 
sessed of  the  following  characteristics :  The  average  length  is  about  18  cm. 
and  the  diameter 
about  40  to  50  mi 
crons,  and  very  uni- 
form throughout 
the  entire  length 
(Fig.  96).  The 
epidermal  scales  can 
only  be  observed 
with  difficulty,  as 
they  are  very  thin 
and  flat,  though 
regular  in  outline. 
They  are  also  very 
broad,  a  single  scale 
frequently  sur- 
rounding the  entire 
fiber;  the  edge  of 
the  scale  is  usually 
finely  serrated. 
The  best  grades  of 
fibers  show  no  me-  Fig.  96. — Mohair  Fibers.  (X350.)  (Micrograph  by  author.) 
duUa,  but  there  are 

usually  to  be  found  (especially  in  domestic  mohair)  coarse,  thick  fibers 
possessing  a  broad  medullary  cylinder,  thus  resembling  the  structure 
of  ordinary  goat-hair,  from  which,  however,  they  are  to  be  dis- 
tinguished by  being  more  slender  and  more  uniform  in  their  diameter. 
Longitudinally,  the  fiber  exhibits  coarse,  fibrous  striations,  approxi- 
mating the  appearance  of  broad  and  regularly  occurring  fissures. 
These  striations  are  usually  much  more  pronounced  than  those  to  be 
found  in  sheep's  wool.  Due  to  the  fact  that  the  surface  scales  lie  very 
flat  and  do  not  project  over  one  another,  the  edge  of  the  fiber  is  very  smooth, 
showing  scarcely  any  serrations  at  all,  which  partially  accounts  for  its 


216 


MINOR   HAIR   FIBERS 


utter  lack  of  felting  qualities.  The  outer  end  of  the  fiber  is  either  slightly 
swollen  or  blunt,  but  never  pointed.  When  viewed  under  polarised  light 
the  fibers  occasionally  show  the  presence  of  a  medullary  canal,  which 
appears  as  a  hollow  space,  giving  an  illumination  somewhat  resembling 
that  of  a  bast  fiber,  and  covering  from  one-fourth  to  one-half  of  the 
diameter. 

5.  Cashmere. — This  fiber  is  obtained  from  the  cashmere  goat  native 
to  Thibet  and  the  district  of  Kashmir  in  northern  India.  It  is  character- 
ised by  very  large  horns  and  the  fleece  consists  of  a  long,  straight,  silky 
fiber,  at  the  roots  of  which,  on  certain  portions  of  the  body,  is  to  be  found 

a  small  quantity  of  very 
fine  wool  of  brownish 
color.  This  latter  is  the 
true  cashmere  of  com- 
merce from  which  the 
renowned  cashmere  and 
Paisley  shawls  are 
made.  Attempts  at 
cultivating  the  cash- 
mere goat  in  other 
countries  have  so  far 
failed.  Cashmere  is 
remarkable  for  its  soft- 
ness, and  is  m  u  c  h 
used  in  the  woolen 
industry  for  the  pro- 
duction of  fabrics 
requiring  a  soft  nap. 
Cashmere  is  the  fiber 
employed  in  the 
manufacture  of  the 
famous  Indian  shawls.  There  are  two  qualities  of  cashmere  wool,  the 
one  consisting  of  the  fine,  soft  down-hairs  and  the  other  of  long,  coarser 
beard-hairs.^  The  former  are  from  Ij  to  3^  ins.  in  length,  13  microns  in 
diameter,  while  the  latter  are  from  3|  to  4^  ins.  in  length  by  60  to  90 
microns  in  diameter.  The  wool-hairs  show  visible  scales  but  no  definite 
medulla,  whereas  the  beard-hairs  possess  a  well-developed  medulla. 
The  cortical  layer  is  coarsely  striated  and  shows  characteristic  fissures. 
^  The  supply  of  true  cashmere  is  relatively  small  as  the  goat  is  not  bred  in  great 
numbers  and  each  goat  yields  but  a  small  weight  of  fiber.  According  to  Barker,  the 
best  cashmere  is  recovered  as  noil  in  the  combing  operation;  the  length  of  the  fiber  is 
from  2  to  3  ins.,  and  the  qualities  are  classified  as  "first"  and  "seconds,"  brown  or 
white.  The  fiber  is  very  light  and  fluffy  and  therefore  needs  much  care  in  spinning. 
It  is  used  for  shawls,  dress  fabrics  and  hosiery  requiring  a  soft  handle  and  light  weight. 


Fig. 


97. — Wool-hairs  of  Cashmere. 
(Micrograph  by  author.) 


(X350.) 


GOAT-HAIR 


217 


At  the  point  of  the  fiber  the  epidermal  scales  are  either  entirely  absent 
or  are  so  thin  as  to  be  scarcely  visible.  The  fiber  is  very  cyhndrical; 
the  scales  have  their  free  edge  finely  serrated,  and  the  edge  of  the  fiber  also 
presents  the  same  appearance  (Fig.  97). 

The  following  table  by  E.  W.  Tetley  (Textile  Mamufacturer)  gives  a 
comparison  between  cashmere  and  some  of  the  other  similar  fibers: 


Diameter. 

Quahty 
in  Wool 

Greatest. 

Least. 

Average. 

Top 
Terms. 

Cashmere 

0.0020 
0.0006 
0.0040 

0.0004 

0.00027 

0.0009 

0.0006 
0.00047 
0.0030 
0.0030 

1/1666 
1/2128 
1/333 
1/333 

90's 

Vicufia 

Over  lOO's 

Goat  hair  (E.  Indian) 

Human  hair  (Chinese) .... 

26's 
26's 

6.  Goat-hair. — Besides  mohair  and  cashmere,  the  hair  of  the  common 
goat  is  also  used  at  times.  In  trade  there  are  fom-  varieties  of  hair  derived 
from  the  goat: 
ordinary  goat-hair, 
meadow  goat-hair, 
angora  wool  (mo- 
hair), and  Thibet 
wool  (cashmere) . 
Goat-hair  has  the 
following  microscop- 
ical characteristics 
(Hohnel):  It  is  white, 
yellow,  brown,  or 
black  in  color,  and 
generally  from  4  to 
10  cm.  long.  It  con- 
sists largely  of  beard- 
hairs,  which,  like 
pulled  wool,  nearly 
always  show  the  hair- 
root.  The  average 
hair  exhibits  the 
following  structure 
(Fig.  98):  At  the  base 

it  is  about  80  to  90  microns  thick;  the  root  is  about  ^  mm.  long;  the  marrow 
is  just  visible  at  the  root,  then  rapidly  increases  in  thickness,  so  that  a  few 


Fig.  98. — Hair  of  Common  Goat.     ( X350.)     Showing  hair- 
root  and  medullated  fiber.     (Micrograph  by  author.) 


218 


MINOR  HAIR  FIBERS 


millimeters  from  the  base  it  is  50  microns  thick,  where  the  thickness  of 
the  hair  amounts  to  from  80  to  90  microns.  The  cortical  layer  from 
this  point  on  forms  a  very  thin  cylinder.  The  cross-section  is  round; 
the  epidermis  consists  of  broad  scales  about  15  microns  long,  the  forward 
edges  of  which  are  scarcely  thickened,  but  appear  as  if  terminating  in  a 
sharp  line;  furthermore  they  are  not  serrated.  The  medullary  cells  are 
thick-walled,  narrow,  and  flattened.     Toward  the  end  the  hair  is  very 


I 

I 


i 


B  A 

FiQ.  99. — Fibers  of  Goat.     A,  Fine  wool-hairs;  B,  coarse  beard-hairs.     (Ldbner.) 


brittle  and  easily  broken.  Other  authors  note  the  presence  of  very  narrow 
air-clefts  between  the  medullary  cells  as  being  quite  characteristic  of  goat- 
hair.  Colored  goat-hair  shows  the  presence  of  pigment  matter  in  all  of  its 
tissues ;  in  such  fillers  the  marrow  appears  black  (Fig.  99) . 

The  hair  obtained  from  the  meadow  goat,  according  to  Hohnel,  consists 
of  wool-hairs  about  30  cm.  long.  At  the  base  it  is  100  microns  thick,  free 
from  marrow;  the  epidermal  scales  here  are  very  narrow,  thin,  and  finely 
serrated,  overlap  each  other  in  thick  layers,  and  have  no  thickened  edges 


GOAT-HAIR 


219 


Around  the  total  circumference  there  are  4  to  5  scales,  whose  free  part  is 
about  10  microns  long  and  40  to  50  microns  broad.  The  fibers  exhibit  a  reg- 
ular and  coarsely  striated  appearance.  In  the  center  of  the  cross-section 
the  fiber  appears  spongy,  exhibiting  a  trace  of  a  kind  of  marrow.  Further 
up  the  fiber  acquires  a  thickness  of  about  90  to  95  microms  and  finally 
120  microns,  without,  however,  changing  its  structure.  About  10  to  15  cm. 
from  the  base,  the  marrow  cells  make  their  first  appearance  as  spindle- 
shaped  cells,  which  often  are  seen  only  in  broad  fibers.  These  cells  gradu- 
ally become  elongated  and  round,  and  finally  occur  continuously  as  a 
marrow  cylinder.  The  cells  themselves  become  less  broad,  and  are 
arranged  in  several  series,  and  finally  form  a  large  cylinder  which  is  sur- 
rounded by  a  very  narrow  cortical  layer  and  a  scarcely  visible  epidermis. 
The  marrow  usually  continues  up  to  the  broken-off  point  of  the  hair. 
The  greatest  breadth  amounts  to  150  microns,  10  microns  on  each  side 
of  which  is  the  cortical  layer.  The  fiber  as  a  whole  is  very  uniformly 
round. 

Hanausek  ^  calls  attention  to  the  fact  that  certain  kinds  of  sheep's  wool 
closely  resemble  goat's  wool,  having  numerous  beard-hairs  present  showing 
a  broad  medulla.  Under  the  microscope  goat-hairs  in  their  middle  part  are 
characterised  by 
broad,  short,  paral- 
lel medullary  cells. 
Air  (together  with 
dried  granular  con- 
tents) is  generally 
present  in  the  med- 
ullary cells  of 
white  hairs,  giving 
the  medulla  the 
appearance  of  a 
broad,  black  band. 
In  the  beard-hairs 
of  coarse  sheep's 
wool  the  appearance 
is  much  the  same 
(Fig.  100,  A  and  B). 
gently  wiirmed,  they 
sharply  and  distinctly 


Fig.  100. — A,  sheep's  wool;  B,  goat's  wool;  W,  wool-hair; 
G,  beard-hair;  e,  epidermis;  /,  fiber  layer;  m,  medulla. 
(After  Hanausek.) 


If,  however,  the  fibers  are  mounted  in  potash  and 
swell  greatly  and  the  medullary  cells  stand  out 
In  wool  these  appear  as  large  round  cells,  while 
in  goat's  hair  they  remain  elongated  and  the  original  parallel  arrangement 
is  not  altered  (see  Fig.  101,  A  and  B).  According  to  Hanausek  this 
difference  is  sufficiently  characteristic  to  permit  of  the  distinction  between 
sheep's  wool  and  goat's  wool  at  a  glance. 

^  Microscopy  of  Technical  Products,  p.  134. 


220 


MINOR  HAIR  FIBERS 


7.  Alpaca  and  its  varieties  vicuna  and  llama  are  the  wools  of  the 
domesticated  goat  of  Peru.  The  animal  is  a  native  of  the  mountainous 
slopes  of  the  Andes,  and  if  left  alone  grows  hair  to  nearly  a  yard  in  length, 
though  the  usual  clip  has  a  staple  about  9  to  10  ins.  long,  when  they  are 
stronger  and  more  uniform.  In  the  fine  qualities  the  staples  are  well 
formed,  and  in  this  respect  resemble  those  of  a  fine  English  luster  or  a 
Cape  kid  mohair;  but  in  the  coarser  qualities  they  are  somewhat  dis- 
organised. 

Alpaca  wools  have  the  disadvantage  of  being  mostly  colored  from 
brown  to  black.  Though  largely  used  in  South  America  for  the  pro- 
duction of  various  fabrics,  they  do  not  find  much  application  in  the 


Fig.  101. — A,  Beard-hair  of  sheep,  and  B,  of  goat  after  warming  in  potash;  /,  fiber  cells, 
becoming  disintegrated;  ni,  medullary  cells,  swollen  and  no  longer  showing  gran- 
ular contents.     (After  Hanausek.) 


general  textile  industry.  In  Bolivia  there  are  about  200,000  alpacas. 
The  animal  belongs  to  the  same  family  as  the  llama  and  vicuna,  but  its 
legs  are  shorter  than  those  of  the  llama.  There  are  also  a  large  numbers 
of  alpacas  in  Peru.^  The  alpaca  is  sheared  about  every  two  years  and 
yields  about  10  lbs.  to  the  fleece.     The  alpaca  skins  are  also  used  for  rugs. 

'  These  animals  are  little  known  to  commerce,  and  are  really  but  little  known 
outside  of  the  Andean  uplands  of  South  America.  The  camels  of  the  Old  World  and 
the  llama  and  allied  species  of  the  New  World,  all  belong  to  the  same  family,  and 
while  the  genus  Ovis  is  to  be  foxmd  over  the  fom*  quarters  of  the  world,  the  llama  and 
its  kind  demand  conditions  of  environment  which  markedly  restrict  their  distribution. 
Even  along  the  extensive  ranges  of  the  Andes,  the  llama  and  alpaca  are  not  found 
north  of  the  Equator,  because  throughout  the  entire  length  of  the  northern  Cordillera 
the  natural  food  of  the  animals,  ichu,  a  coarse  fine-pointed  grass,  is  absent.  The  llama 
and  alpaca  have  been  domesticated  from  the  earliest  antiquity.  In  ancient  days 
their  flesh  formed  the  main  meat  supply  of  the  Inca,  and  the  llama  was  employed  as 
the  chief  means  of  transportation  for  merchandise,  while  its  coarse  hair  supplied  the 


ALPACA  221 

There  is  another  product  in  trade  which  goes  by  the  name  of  \'icima 
(French  vicogne)  which  must  not  be  confused  with  the  true  South  American 
fiber,  it  being  simply  a  trade  name  for  a  mixture  of  cotton  and  wool. 
"  Gorilla  "  j-arn  is  a  complex  mixture  of  such  hair  fibers  as  alpaca,  sheep's 
wool,  and  mohair,  with  cotton  and  silk  waste.  It  is  rugged  and  knotty 
in  appearance,  and  is  chiefly  used  for  the  manufacture  of  ladies'  dress 
material.     The  name  alpaca  is  also  given  to  a  varietj'  of  wool  substitute. 

The  South  American  wools  often  give  rise  to  wool-sorter's  disease  in 
those  handhng  them.  This  disease  is  anthrax  and  is  caused  by  the 
presence  of  a  certain  microbe  in  the  fiber.  All  alpaca,  cashmere,  Persian 
and  camel-hair  fleeces  should  be  opened  over  a  fan  with  a  down  draught. 
Van  mohair  or  Turkish  mohair  should  be  washed  and  sorted  while  damp. 
Persian  wool  should  be  disinfected  before  sorting.  Wool-sorter's  disease 
is  caused  by  Bacillus  anthracis,  which  may  enter  the  system  either  by  the 
skin  (through  the  medium  of  an  abrasion  or  cut)  or  by  the  internal  organs, 
being  introduced  with  the  food.  In  the  former  case  it  gives  rise  to  pustules, 
which  become  painful  and  cause  excessive  perspiration,  fever,  delirium, 
and  sundry  disorders.  In  the  latter  case  it  gives  rise  to  the  most  serious 
results,  leading  to  blood-poisoning  and  inflammation  of  the  lungs,  which 
often  prove  speedily  fatal. ^ 

True  alpaca  is  obtained  from  the  cultivated  South  American  goat 
Auchenia  paco.  It  occurs  in  all  varieties  of  colors,  from  white,  through 
brown,  to  black.  The  reddish  brown  and  not  the  white  variety,  however, 
is  the  most  valuable.  Like  other  goat-hairs,  alpaca  consists  of  two  varie- 
ties of  fibers,  a  soft  wool-hair  and  a  stiff  beard-hair.  The  wool-hairs 
of  the  reddish  brown  variety  are  from  10  to  20  cm.  in  length  -  and  from 

lower  classes  with  the  raw  materials  from  which  were  woven  their  apparel  and  blankets. 
Attempts  have  been  made  to  introduce  the  llama  into  Austraha,  but  without  success. 
The  alpaca  also  fails  to  thrive  when  removed  from  its  high  altitudes,  which  range 
about  13,000  ft.  above  the  sea.  Higher  still,  the  guanaco  and  vicuna,  the  wild  members 
of  the  species,  are  foimd. 

1  South  American  wools  and  fibers  that  are  infected  with  anthrax  frequently  have 
to  be  properly  sterilised  before  manufacturing.  Treatment  with  formaldehyde  vapors 
is  often  employed.  The  Dinsley-Puhnan  sj'stem  of  sterihsing  anthrax-infected  wools 
uses  an  apparatus  which,  by  a  combination  of  X-rays  and  ultra-violet  rays,  will 
sterilise  anthrax  germs  as  effectuall}'  as  the  formaldehyde  system,  but  wiU  do  it  in  the 
bale  and  so  save  time,  labor  and  expense  in  unpacking,  washing,  scouring  and  re-packing 
the  bale. 

2  According  to  Barker,  the  ordinary  alpaca  cHp  fields  a  length  of  about  9  ins., 
but  much  is  allowed  to  grow  for  two,  or  even  three  years,  when  it  reaches  a  length  of 
about  30  ins.  This  great  length,  however,  is  hable-  to  cause  weakness  in  the  fiber 
resulting  in  much  waste  in  manufacture.  Alpaca  wool  is  usually  classified  as  "low," 
"medium,"  and  "fine."  In  England  the  fiber  is  generally  known  as  "Arequipa 
fleece,"  Arequipa  being  the  Peru\Tan  port  from  which  it  is  shipped.  Alpaca  is  mostly 
used  for  dress  goods,  linings  and  overcoat  facings.  _        .  - 


222 


MINOR  HAIR  FIBERS 


11  to  35  microns  in  diameter  (Fig,  102).  The  fiber  is  very  smooth,  the 
serrations  on  the  edge  being  faint  and  indistinct,  and  the  scales  are 
almost  imperceptible  and,  in  many  cases,  apparentl}''  absent  altogether; 
the  diameter  is  also  very  uniform,  and  there  are  coarse  brown  longitudinal 
striations  but  no  medulla,  though  isolated  medullary  cells  are  at  times 
observed.  The  wool-hairs  of  the  white  variety  are  very  distinctly  serrated 
on  the  edge,  and  the  fiber  is  not  so  uniformly  thick.  The  beard-hairs  of 
the  brown  variety  are  comparatively  few  in  number,  are  from  5  to  6  mm. 
in  length  and  about  60  microns  in  diameter,  and  the  latter  is  very  uniform. 
A  very  broad  continuous  medullary  cylinder  is  present,  45  to  50  microns 

wide;  the  medul- 
lary cells  are  very 
indistinct,  but  are 
filled  with  coarse 
granules  of  matter. 
The  cortical  layer 
shows  occasional 
fissures,  and  the 
brown  coloring 
matter  is  princi- 
pally distributed 
through  the  ex- 
ternal cortical 
layer,  though  very 
irregularly.  The 
beard-hairs  of  the 
white  variety  also 
occur  rather  spar- 
ingly ;  they  are 
from  20  to  30  cm. 
Fig.  102. — Alpaca  Fibers.     (X350.)     (Micrograph  by  author.)    in    length,    and    35 

microns  in  thick- 
ness at  the  lower  end  and  about  55  microns  towards  the  upper  end. 
The  medulla  is  broad  and  continuous,  and  nearly  always  filled  with 
a  coarsely  granulated  matter  of  a  gray  color  (Fig.  103).  The  medulla 
consists  of  a  single  row  of  short  cylindrical  cells,  but,  as  the  walls 
are  very  thin,  the  cells  are  to  be  seen  only  with  difficulty.  The  cortical 
layer  is  coarsely  striated  and  frequently  shows  fibrous  fissures;  the  edge 
of  the  fiber  is  not  sharply  serrated. 

The  fibers  of  alpaca  are  coarser  than  either  vicuna  or  camel-hair,  and 
the  thick  medullated  fibers  are  present  in  much  greater  proportion  than 
the  fine  woolly  fibers.  The  distribution  of  the  pigment  matter  is  more 
uniform  in  alpaca  fibers  than  in  those  of  vicuna  or  camel-hair. 


VICUNA  WOOL 


223 


The  alpaca  is  smaller  than  the  llama  and  weighs  on  the  average  about 
180  lbs.  The  neck  is  shorter  and  is  well  covered  with  hair  which  forms  in 
the  region  of  the  throat  a  distinct  beard-like  fringe.  A  cross-breed 
between  the  alpaca  and  the  llama  has  resulted  in  the  production  of  hair 
of  good  length,  luster  and  fineness.  The  "  suri  "  type  of  alpaca,  an  animal 
with  a  distinct  curl  along  the  entire  length  of 
the  fiber,  is  much  sought  after,  as  this  fiber  is 
in  good  demand  by  manufacturers  for  the  pro- 
duction of  a  special  artistically  finished  cloth.  ^~^^M  W^>&k~k 
This  "suri"  type  is  the  outcome  of  mere  chance 
breeding.  The  hair  of  the  alpaca  is  of  remark- 
able fineness  and  luster,  and  there  is  a  variety 
of  colors  ranging  from  white  through  blue,  gray, 
fawn  and  orange  to  dark  brown.  These  colors 
show  a  great  fastness  to  light  and  to  milling 
and  finishing  operations,  and  are  being  much 
used  in  the  hosiery  trade  for  natural  colored 
alpaca  yarns.  There  is  no  doubt  that  a  much 
wider  market  could  be  opened  were  there  a 
larger  supply  of  this  very  attractive  fiber. 

8.  Vicuna  Wool  is  another  South  American 
product  obtained  from  Auchenia  viccunia,  the 
smallest  of  this  general  class  of  goat-like  camels. 
It  is  not  a  cultivated  animal,  and  is  evidently 
disappearing,  hence  the  fiber  is  not  met  with  in 
trade  to  any  great  extent  at  the  present  time. 

The  vicuna  is    antelope-like  in    shape,  and 


Fig.  103. — Fibers  of  Alpaca. 
(Hohnel.)     (X350.) 

in  appearance,  color  and  movement  resembles  a,  Beard-hair  containing  med- 
the  gazelle  of  East  Africa.  It  weighs  from  75  ulla;  6,  wool-hair  free  from 
to  100  lbs.  The  head  is  proportionately  too 
large  for  the  size  and  delicacy  of  the  neck,  which 
is  long  and  curving.  The  fleece  is  light  reddish- 
brown  in  color,  shading  off  to  a  light  fawn  down 
the  legs  and  along  the  under  surface  of  the  body. 
On  the  breast  is  long,  coarse,  white  hair  which 
gives  the  animal  a  very  characteristic  appearance 
is  very  valuable ;  it  is  more  esteemed  than  the  down  of  the  Canadian  beaver 
or  the  fleece  of  the  Syrian  goat.  During  recent  years  some  vicuna  animals 
have  been  domesticated  and  used  for  cross-breeding  purposes  with  the 
alpaca,  resulting  in  the  production  of  a  hair  which  for  softness  of  handle 
and  fineness  of  fiber  will  be  difficult  to  equal.  Steps  are  now  being  taken 
to  farm  these  valuable  hair-bearing  animals  along  approved  scientific 
lines  and  stringent  laws  have  been  enacted  in  Peru  to  protect  the  vicuna 


medulla;  e,  cusp-like  scales, 
thin  and  broad;  k,  granu- 
lated streaks  on  the  fibrous 
layer;  m,  medullary  cylin- 
ders; z,  small  medullary 
cells. 

The  hair  of  the  vicuna 


224 


MINOR   HAIR   FIBERS 


from  destruction.  By  the  process  of  selection,  judicious  breeding  and 
proper  farming  and  cross-breeding,  it  should  be  possible  to  produce  a  hair 
of  very  great  intrinsic  value,  of  exceptional  softness  in  handle,  and  of  good 
length  and  luster.  The  cross  between  the  alpaca  and  vicuna  is  known 
as  the  "  paco  vicuna." 

Vicuna  is  a  soft,  delicate  fiber,  usually  of  a  reddish  brown  color,  and 
much  resembles  alpaca,  though  it  is  usually  finer  that  either  alpaca  or 

camel-hair,  and  is  char- 
acterised by  a  very  soft, 
almost  greasy,  touch. 
It  also  shows  the  pres- 
ence of  a  fine  wool-hair 
and  a  coarse  beard- 
liair ;  the  former  is  from 
10  to  20  microns  in  diam- 
eter, while  the  latter  is 
75  microns  wide.  The 
scales  of  the  wool-hair 
are  very  regular  and 
i-athcr  easy  to  distin- 
guish, but  generally  no 
medulla  is  to  be  seen. 
The  cortical  layer  is 
finely  striated  and  fre- 
quently contains  fibrous 
fissures  (Fig.  104).  The 
beard-hairs,  however, 
show  a  well-developed 
medulla,  mostly  dark  in  color.  The  fibers  of  the  wool-hair  are  very 
uniform  in  diameter  and  about  20  cms.  in  length.  Mitchell  and  Prideaux  ^ 
call  attention  to  the  fact  that  the  disposal  of  the  pigment  is  an  important 
characteristic  of  the  vicuna  fiber.  In  the  small  fibers  it  is  regularly 
distributed  in  uniform,  faintly  defined  dashes.  In  the  large  medullatcd 
fibers,  however,  the  distribution  of  the  pigment  may  take  a  different  form; 
in  addition  to  the  streaks  and  lines  found  in  the  smaller  fibers,  there 
may  occasionally  be  noted  circular  pp,tches  of  pigment. 

An  artificial  wool  substitute  also  goes  by  the  name  of  vicuna  or  vicogne 
yarn,  but  bears  no  resemblance  to  the  true  South  American  fiber.  It  con- 
sists principally  of  a  mixture  of  cotton  with  sheep's  wool,  but  is  frequently 
mixed  more  or  less  with  wools  and  coarse  beard-hairs  of  poor  spinning 
qualities  obtained  from  various  goats  (of  Asia  Minor),  from  camels,  and 
from  South  American  wools.  It  is  of  poor  quality  and  generally  yellowish 
1  Fibers  Used  in  Textile  Industries,  p.  34. 


Fig.  104. 


-Vicuna  Fibers.     (XS.'jO.) 
author.) 


(Micrograph  by 


LLAMA  FIBER 


225 


brown  in  color.  It  is 
only  used  for  felted  ma- 
terials or  for  very  coarse 
fabrics. 

The  table  on  page  226 
given  by  E.  W.  Tetley 
{Textile  Manufacturer), 
compares  the  different 
physical  properties  of  the 
fibers  of  mohair,  alpaca 
and  camel's  hair. 

9.  Llama  Fiber.— This 
fiber  is  obtained  from  a 
goatlike  animal  (Fig.  105) 
indigenous  to  several 
South  American  coun- 
tries, principally  Peru 
and  Bolivia.  The  latter 
country  contains  about 
500,000  llamas  and  they 
constitute  the  traditional 
pack  animal  of  the  coun- 


FiG,  105. — ^Llama. 


(Micrograph  by  author. 


try.  They  are 
sheared  at  intervals 
of  two  to  five  years, 
though  often  the 
shearing  does  not 
take  place  until  the 
animal  dies.  When 
sheared  each  two 
3'ears  the  llama 
gives  about  5  lbs. 
of  wool.  The  fiber 
is  quite  coarse  and 
always  very  dirty. 
Most  of  the  wool 
is  used  by  the  na- 
tives in  their  weav- 
ing and  ver\^  little 
of  it  comes  into 
general  trade. 

The  fiber  of  llama 
exhibits  scarcely 


226 


MINOR   HAIR   FIBERS 


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CAMEL-HAIR  227 

any  visible  surface  scales,  but  has  well-developed  isolated  medullary  cells. 
It  also  consists  of  two  classes  of  fibers,  both  of  which  show  longitudinal 
stria tions  (Fig.  106).  The  wool-hair  is  from  20  to  35  microns  in  diameter, 
while  the  beard-hair  averages  150  microns.  The  llama  wool  comes  from 
the  Auchenia  llama,  a  cultivated  animal. 

The  llama  is  the  largest  of  the  Andean  camels.  Its  average  weight  is 
about  250  lbs.,  and  it  has  a  life  of  ten  to  fourteen  years.  Its  fleece  is  thick 
and  coarse;  the  neck,  which  is  long,  is  well  covered,  but  the  throat  is 
devoid  of  long  hair.  The  fleece  terminates  abruptly  along  the  bottom 
line  of  the  trunk,  and  has  a  staple  of  10  to  12  ins.  in  length.  It  is  prin- 
cipally used  in  the  making  of  sacks  and  coarse  blankets. 

The  wool  from  another  variety,  Auchenia  huanaco,  is  used  to  some 
extent  in  South  America,  though  it  seldom  appears  as  such  in  general  trade. 
This  latter  animal  is  not  cultivated,  but  is  hunted  wild,  and  is  gradually 
disappearing.  Huanaco  and  llama  are  nearly  always  mixed  more  or  less 
with  alpaca  and  brought  into  trade  under  the  latter  name. 

Huanaco  or  guanaco,  like  the  vicuna,  is  not  domesticated.  It  is 
somewhat  larger  than  the  vicuna,  and  its  fleece  is  russet-brown  in  color 
with  an  overmantle  of  long,  coarse  hair  of  slightly  darker  hue.  The 
guanaco  has  never  been  domesticated,  nor  has  it  ever  been  used  for  cross- 
breeding purposes. 

There  is  but  little  difference  to  be  found  among  these  three  fibers, 
owing  to  the  close  relationship  of  the  animals  from  which  they  are  derived, 
and  more  especially  as  different  portions  of  the  fleece  from  all  varieties  of 
Auchenia  give  wools  of  entirely  different  quality,  with  respect  to  color, 
fineness  of  staple,  and  purity  from  coarse  stiff  hairs ;  and  the  corresponding 
portions  from  the  different  animals  are  usually  graded  together. 

10.  Camel-hair  is  used  to  quite  an  extent  in  clothing  material,  and  is 
characterised  by  great  strength  and  softness.  It  has  considerable  color 
in  the  natural  state,  which  does  not  appear  capable  of  being  destroyed  by 
bleaching;  hence  camel-hair  is  either  used  in  its  natural  condition  or  is 
dyed  in  dark  colors.  There  are  two  distinct  growths  of  fiber  on  the  camel : 
the  wool-hair,  which  is  a  fine  soft  fiber,  largely  employed  for  making 
Jager  cloth,  and  the  beard-hair,  which  is  much  coarser  and  stiffer,  and  is 
mostly  used  for  carpets,  blankets,  etc.^  Both  fibers  show  faint  markings 
of  scales  on  the  surface  and  well-developed  longitudinal  striations.     The 

1  Barker  states  that  true  camel-hair  is  a  fine,  downy  material,  about  5  ins.  long, 
of  a  yellowish  or  brownish  color.  Long,  strong  fibers  are  invariably  found  in  tliis, 
coming  from  the  underparts  of  the  camel,  and  these  must  be  combed  out.  There  are 
many  types  of  camel-hair,  such  as  Chinese,  Persian  and  Russian,  but  all  are  classified 
as  firsts,  seconds  and  thirds,  the  first  being  freer  from  coarse  fibers  and  more  uniform. 
True  camel-hair  is  not  very  strong,  and  thus  needs  careful  treatment  in  manufacture 
to  avoid  excessive  waste.  The  fine  fiber  is  employed  for  dress  goods  and  linings, 
while  the  coarse  fiber,  which  is  exceptionally  strong,  is  used  for  beltings  and  the  like. 


228 


MINOR  HAIR   FIBERS 


beard-hair  always  exhibits  the  presence  of  a  well-defined  medulla,  which 
is  large  and  continuous,  while  the  wool -hair  cither  shows  only  isolated 

medullary  cells  or  none 
at  all.  The  diameter 
of  the  wool-hair  is  from 
14  to  28  microns,  while 
the  beard-hair  averages 
75  microns  (Fig.  107). 
The  wool-haii's  are  about 
5  to  6  cm.  in  length,  are 
rather  regularly  waved, 
and  are  usually  yellow 
to  brown  in  color;  while 
the  others  are  about  10 
cm.  long  and  are  dark 
''^^^^^  Ti.    ' ->    X  ^\^^/  brown  to  black  in  color. 

The  epidermal  scales  of 
the  latter  are  quite 
rough,  which  give  the 
edge  of  the  fiber  a  saw- 
Fi(j.  107.— Camel-hair.    (X3.50.)    (Microsraph  l)y  author.)    toothed      appearance. 

The  presence  of  large 
spots,  or  motes,  of  brown  coloring  matter,  especially  in  the  medulla, 
is    quite    characteristic.      These    are    usually  granular  in  form.      The 


Fig.  108. — Hair  Fibers.     (1)  Fine  alpaca;    (2)  coarse  alpaca;    (3)  Russian  camel-hair; 
(4)  Chinese  camel-hair;   (5)  Thibet  cashmere;   (6)  East  Indian  goat-hair.    (Tetley.) 


beard-hairs  of  the  camel  are  to    be    distinguished    from    corresponding 
cow-hairs  by  smaller  diameter,  thicker  epidermis,  and  narrower  medullar} 


CAMEL-HAIR 


229 


cells  with  thicker  walls,  which  are  generally  darker  in  color  than  the 
enclosed  pigment  matter.  Camel-hair  is  to  be  distinguished  from  cow- 
hair  by  the  thick-walled  medullary  cells  and  the  streaks  of  coloring 
matter. 

According  to  Mitchell  and  Prideaux  the  fibers  of  camel-hair  are  generally 
coarser  than  those  of  vicuna,  a  greater  proportion  of  the  larger  medullated 
fibers  being  present.  The  scales  of  the  finer  fibers  are  also  less  conspicuous 
than  those  of  vicuna,  hence  the  latter  has  a  softer  touch.  The  distribution 
of  the  pigment  cells  in  camel-hair  is  very  irregular;  some  of  the  finest 
fibers  appear  to  have  none,  while  in  others  flecks  and  dashes  of  pigment 
may  be  seen  in  the  otherwise  clear  transparent  hair. 

Prideaux  ^  gives  the  following  summary  of  differences  between  vicuna, 
camel-hair,  and  alpaca: 


Vicuiia. 


The  finest  fibers  of  the  three; 
few  coarse  medullated  ex- 
amples; scales  least  con- 
spicious 

Largest  difference  in  size  be- 
tween non-  and  medullated 
fibers 

Pigment  always  present,  ex- 
cept in  a  few  of  the  large 
opaque  medullated  fibers 

Amount  of  pigment  very  uni- 
form ;  disposal  rather  regu- 
lar; circular  nuclei  rare, 
and  only  in  medulated 
fibers 


Camel-hair. 


Intermediate  in  fineness; 
medullated  fibers  common : 
scales  most  conspicuous 


Many  of  the  smaller  fibers 
colorless 

Amount  of  pigment  variable ; 
disi)osal  highly  irregular, 
circular  nuclei  frequently 
seen  in  fibers  of  all  sizes. 
Distinctive  streaks  and 
blurs  well  marked 


Alpaca. 


The  coarsest  fibers,  few  non- 
medullated 


Least  difference  between 
non-  and  medullated  fibers 

Many  fibers,  especially  the 
larger  ones,  colorless 

Amoimt  of  pigment  very 
variable;  disposal  very  reg- 
ularly diffused,  in  pale 
specimens  almost  as  if 
dyed;  circular  nuclei  never 
seen 


Notwithstanding  these  characteristic  differences,  it  is  a  very  difficult 
matter  to  differentiate  definitely  between  these  three  forms  of  hair  fibers, 
and  an  opinion  as  to  which  fiber  is  under  consideration  must  usually  be 
referred  to  other  considerations  than  a  microscopic  test. 

Camel-hair  noils  are  the  short  fibers  obtained  from  the  combing  of 
camel-hair.  They  also  consist  of  two  kinds  of  fiber:  (a)  very  fine,  curly, 
reddish  or  yellowish  brown  hairs,  about  4  ins.  in  length,  and  known  in 
trade  as  camel-wool;  and  (6)  coarse,  straight,  dark  to  blackish  brown 
body  hairs,  about  2  to  2^  ins.  in  length. 


1  Jour.  Soc.  Chem.  Ind.,  1900,  p.  8. 


230 


MINOR   HAIR   FIBERS 


11.  Cow-hair  is  extensively  employed  as  a  low-grade  fiber  for  the 
manufacture  of  coarse  carpet  yarns,  blankets,  and  a  variety  of  cheap 

felted  goods.  It  is  seldom  used  alone, 
however,  on  account  of  its  short  staple. 
It  comes  principally  from  Siberia.  The 
diameter  of  cow-hair  varies  from  84  to 
179  microns  and  the  length  from  H  to 
5  cm.  The  fibers  occur  in  a  variety  of 
colors,  including  white,  red,  brown,  and 
black.  In  its  microscopic  appearance 
the  surface  of  the  fiber  is  rather  luster- 
less;  the  ends  are  very  irregular,  being 
blunt  and  divided.  The  medullary  canal 
is  well  marked,  occupying  about  one-half 
the  diameter  at  the  base  and  tapering 
towards  the  free  end,  where  it  occu- 
pies only  one-fourth  the  diameter. 
Isolated  medullary  cells  are  also  of 
frequent  occurrence  (Fig.  109).  Cow- 
hair  (including  also  calf-hair)  nearly 
always  shows  the  hair-root,  as  the 
fibers  are  removed  from  the  hide  by 
(Hohnel.)  (X300.)  (/,  characterLstic  liming  and  pulling.  Cow-hair  may  be 
fissures  in  marrow:  //),  marrow  or  distinguished  from  goat-hair  by  the 
medulla  filled  with  air;  /,  fibrous  number  of  epidermal  scales,  by  the 
fissures;  e,  tile-shaped  scales.  f^j^^^   -^  ^^^  medullary   canal,  and   by 

the  single  row  of  cells  in  the  medulla. 
The  medulla  does  not  extend  to  the  apex,  which  is  also  usually  devoid 
of  epidermis. 

Cow-hair  shows  the  presence  of  three  kinds  of  fibers: 

1.  Thick  stiff  beard-hairs  from  5  to  10  cm.  in  length,  and  retaining  a  long  narrow 
hair  follicle;  above  this  is  the  neck  of  the  hair,  containing  a  medullary  cylinder  con- 
sisting of  a  single  series  of  cells  as  well  as  isolated  medullary  cells.  At  this  part  of 
the  fiber  the  epidermal  scales  are  very  thin  and  broad,  and  the  forward  edges  present 
a  serrated  appearance;  the  neck  of  the  hair  is  about  120  microns  in  thickness.  Above 
this  the  hair  rapidly  increases  to  about  130  microns  in  thickness,  and  the  medullary 
cylinder  becomes  broad  (75  microns)  and  consists  of  narrow  brick-shaped  elements, 
arranged  one  on  top  of  the  other.  The  cortical  layer  is  finely  striated,  the  epidermis 
is  indistinct,  and  the  edge  of  the  fiber  is  smooth.  The  medullary  cells  are  very  thin- 
walled  and  contain  a  considerable  amount  of  finely  granulated  matter.  Toward  the 
pointed  end  the  fiber  becomes  colorless,  and  shows  distinct  fibrous  fissures;  the  medul- 
lary cylinder  disappears,  but  the  epidermis  is  not  altered.  The  chief  difference  between 
these  hairs  and  the  beard-hairs  of  the  goat  is  that  in  the  former  the  medullary  cells 
consist  of  only  a  single  series,  and  are  very  thin-walled,  and  are  also  frequently  isolated 
from  one  another,  while  they  are  filled  with  finely  granulated  matter. 


Fig.  109. — a,  Cow-hair;    b,    goat-hair. 


HORSE-HAIR  231 

2.  Soft,  fine,  beard-hairs  possessing  the  same  general  structure  as  the  foregoing, 
but  not  so  thick,  the  neck  of  the  hair  being  75  microns  in  diameter  and  not  possessing 
any  medulla.  Above  this  the  medullary  cylinder  consists  of  very  thin-walled  cells 
arranged  in  isolated  groups;  the  epidermal  scales  overlap  one  another  and  are  almost 
cyUndrical,  are  narrow,  and  with  finely  serrated  edges.  About  1  cm.  from  the  base 
the  medullary  cylinder  becomes  discontinuous  and  breaks  up  into  isolated  medullary 
cells,  which  continue  until  the  middle  of  the  fiber  is  reached,  where  they  disappear 
completely ;  toward  the  pointed  end  of  the  fiber  they  reappear  and  again  become  a  con- 
tinuous cylinder,  consisting  of  only  a  single  series  of  cells,  however.  These  are  well 
fiUed  with  a  dark  medullary  substance. 

3.  Very  fine  soft  wool-hairs,  free  from  medulla,  and  at  most  only  1  to  4  cm.  in 
length,  and  frequently  only  20  microns  in  thickness.  The  epidermal  scales  are  rough, 
causing  the  edge  of  the  fiber  to  be  uneven  and  have  a  serrated  appearance.  The  hairs 
also  show  frequent  longitudinal  fibrous  fissures. 


Calf-hair  has  the  same  general  structure  and  appearance,  though 
there  is  a  greater  amount  of  soft  wool-hairs  present. 

As  cow-hair  is  at  times  to  be  met  with  in  admixture  with  wool  as  an 
adulterant  of  the  latter,  the  fol- 
lowing method  of  distinguishing 
between  the  two,  devised  by  Han- 
ausek,  is  of  interest.  The  micro- 
chemical  reaction  of  cow-hair  with 
a  warm  solution  of  potash  is  very 
Similar  to  that    of    goat-hair  since  mW      i^^ 

in  both    fibers  the    medullary  cells  .^      ,,„      ,  ^^  ■      c   t  ■     . 

,        ,  J     1         1  Fig.  110. — A,  Hau-  of    Leicester    wool    m 

are  transversely  elongated  and  ar-      ^,^^^^.  j^  ^^^^  ^f^^^  warming  in  potash; 

ranged     parallel    to    one    another.       c,   cow-hair  after  warming   in  potash. 

An  important  distinction  from  goat-      (After  Hanausek.) 

hair,   however,   is  the  presence   of 

transverse  air-spaces.     Figure  110  shows  the  comparison  between  sheep's 

wool  and  cow-hair. 

12.  Minor  Hair  Fibers. — (a)  Horse-hair  has  a  diameter  of  80  to  100 
microns  and  a  length  of  1  to  2  cm.  (Fig.  111).  Like  cow-hair,  it  also 
occurs  in  a  variety  of  different  colors.  Horse-hair  is  more  lustrous  than 
the  foregoing,  however,  and  though  when  viewed  under  the  microscope 
the  ends  of  the  fibers  are  irregular  and  often  forked,  they  taper  off  to  points. 
The  medullary  cylinder  is  rather  large,  occupjdng  about  two-thirds  of  the 
diameter  at  the  base  of  the  fiber  and  tapering  to  about  one-fourth  of  the 
diameter  at  the  free  end.  The  medulla  consists  of  one  to  two  rows  of 
very  narrow  leaf-shaped  cells.  Isolated  medullary  cells  are  of  frequent 
occurrence,  especially  at  the  point.  The  cortical  layer  frequently  contains 
numerous  short  orifices  or  fissures.  These  remarks  refer  to  the  body- 
hairs  of  the  horse ;  the  hairs  of  the  tail  and  mane  are  much  longer,  reaching 
from  several  inches  to  a  foot  or  more.     They  find  but  little  use  in  ordinary' 


232 


MINOR  HAIR  FIBERS 


textiles,  but  are  much  used  as  stuffing  materials  in  the  manufacture  of 

upholstery. 

(b)  Cat-hair  var- 
ies in  diameter  from 
14  to  34  microns  and 
in  length  from  1  to 
2  cm.  The  fibers 
occur  in  a  variety 
of  colors  and  have  a 
good  luster.  The 
ends  are  quite  regu- 
lar and  very  pointed. 
The  medullary  canal 
contains  a  single  se- 
ries of  regular  cells 
occupying  one-half 
to  three-fifths  of  the 
diameter  of  the  fiber. 
The  cortical  layer  is 
well   developed,  and 

Fig.  111. — Horse-hair.     (XlOO.)     (Micrograph  by  author.)  ,  ,     ^-^ 

grooved  so  as  to  nt 

over  the  medullary 
cells.  There  is  a 
thin  irregular  epider- 
mis which  envelops 
the  fiber  (Fig.  112). 

(c)  Rabbit  -  hair 
fibers  are  usually 
light  brown  in  color 
and  measure  from 
34  to  120  microns  in 
diameter,  and  from. 
1  to  2  cm.  in  length. 
The  medullary  cana.l 
is  filled  with  several 
series  of  cells,  quad- 
rangular in  shape 
and  with  thin  walls. 
They  are  also  ar- 
ranged in  a  very 
regular  manner.  By 
careful     observation 


Fig. 


112.— Hairs  of  Cat. 
coarse  beard-hair. 


(X350.)     yl,  Fine-wool  hair;   B, 

(Micrograph  by  author.) 


RABBIT-HAIR 


233 


spiral  striations  may  be  noticed  on  the  finer  fibers.  The  epidermal 
scales  are  very  thick  and  their  forward  edges  terminate  in  a  sharp 
point  (Fig.  113). 
Each  scale  is  placed 
cornucopia-like  into 
the  next  lower  one, 
and  is  drawn  out 
into  1  to  3  large 
waves.  At  the  base 
of  the  fiber  the  med- 
ulla consists  of  a 
single  row  of  cells, 
above  the  middle 
this  increases  to  2  to 
4  rows,  and  further 
along  the  fiber  the 
number  of  rows  of 
cells  increases  up  to 
8,  when  the  hair 
becomes  very  wide 
(Fig.  114).  Like 
most  pelt-hairs,  the 
fibers  are  somewhat 
flattened  at  the  base, 
and  quite  so  at  their  broadest  part.  The  cortical  layer  is  only  apparent 
towards  the  point  where  the  medulla  ceases.    The  fine  wool-hairs  of  the 


Fig.  113.— Rabbit-hair.    (X350.)    A,  Wool-hair;   B,  beard- 
hair.     (Micrograph  by  author.) 


fBji     jiiL  jji  ^i^^P    ^1  ii-^iiuji    JimiJii 


'<r3fjf.n  iMm^.t.mjjr*'^fm 


r^V-^vji«^nj>m..^m'!.i0ii.^-mm'.mr>»-'.Mmfm^^ 


•-'•'^-■••,-i-;tn,„-i-i,^,,,-i-,iii,'^,^-fikuiki'rA?ut-Mi!-mi^{i  ifh-'-ff  —  -tn r-iiiHii'm  inrtr-i'^'S "■•-'"•"■••'- ■''-''■•-'^'^■'•^■i'^ii'*"'-^'^"'-^-'-*-'"-  --—^ 


Fig.  114. — Fibers  of  Rabbit-hair.     A,  Fine  fur  fibers;  B,  coarse  beard-hairs. 


234  MINOR  HAIR  FIBERS 

rabbit  are  much  thinner  than  the  above,  the  greatest  thickness  being 
about  20  microns.  Otherwise  they  correspond  in  structure  to  that  part 
of  the  above  fiber  near  the  base. 

(d)  Deer-hair. — This  has  a  very  characteristic  structui'e.  It  is  2  to  4 
cm.  long,  brittle,  white  at  the  lower  end  and  brown  at  the  thinner  upper 
end.  Most  of  the  hairs  still  show  the  thin  small  root  and  the  natural 
point.  The  root  is  relatively  very  small  (on  the  prepared  washed  hairs 
90  microns  broad  and  300  microns  long).  It  passes  into  a  neck  about 
250  microns  long,  which  is  only  60  microns  thick  and  without  any  medulla. 
This  neck  portion  consists  of  short  fibers  without  granulation,  con- 
taining numerous  broad  fissures,  and  of  a  very  soft,  scarcely  visible  epi- 
dermis, consisting  of  narrow,  transversely  broadened  serrated  elements. 
Then  the  hair  suddenly  becomes  cone-shaped,  thicker,  and  increases  in 
diameter  to  360  to  400  microns.  The  lai'ge  medulla  can  no  longer  be  seen 
without  further  preparation.  The  soft  epidermis  is  scarcely  visible;  the 
total  breadth  of  the  fiber  is  filled  up  with  large  medullary  cells,  which 
besides  appear  very  thick-walled  and  almost  isodiametric  (35  to  40  microns 
broad  and  25  to  35  microns  long).  The  cross-section  through  the  fiber, 
however,  shows  that  the  cell-walls  within  the  outermost  zone  are  some 
10  to  12  microns  thicker,  while  all  those  lying  farther  inside  are  quite 
thin.  The  medullary  cells  are  very  large;  all  of  them  are  apparently 
entirely  empty  or  only  filled  with  air;  the  cortical  layer  cannot  be  seen. 
Towards  the  point  the  hair  again  becomes  thinner.  At  this  point  is  to  be 
found  a  brown  pigment  (beyond  the  limits  of  the  medullary  cells,  and  in 
median  layer).  Nearer  the  point  the  cell- walls  themselves  become  brown 
and  also  contain  a  brown  substance.  The  medullary  continually  becomes 
thinner,  and  consists  finally  of  only  one  row  of  cells.  At  the  very  point 
the  fiber  consists  only  of  the  cortical  layer  and  the  epidermis. 

Besides  these  thick  hairs,  there  are  also  found  thin,  brown,  short 
hairs,  as  well  as  intermediate  forms.  They  have  the  same  typical  struc- 
ture. The  cortical  layer  in  these  does  not  appear  so  much  diminished, 
and  throughout  the  entire  length  of  the  fiber  there  is  a  brown  pigment 
to  be  found,  at  least  on  the  upper  surface.  At  the  end  of  the  fiber  the 
epidermal  scales  are  thick,  very  short,  and  overlap  one  another  very 
distinctly,  being  enclosed  by  one  another  in  a  tubular  manner  (Hohnel). 

(e)  Boar  Bristles. — Under  the  microscope  these  appear  striped,  up 
to  500  microns  thick.  Their  lower  portion  is  free  from  meduUa,  or  with 
a  discontinuous  medullary  cylinder;  the  upper  part  has  weU-marked 
medulla,  which  in  cross-section  appears  star-shaped,  on  account  of  which 
the  bristles  can  be  easily  split  at  the  ends.  The  epidermis  is  in  several 
layers.  It  consists  of  3  to  4,  and  more,  layers  of  thin  scales,  which  over- 
lap one  another,  and  the  thin  edges  of  which  are  corroded  in  a  serrated 
manner.     Hence  from  each  of  the  broad  epidermal  scales  only  a  narrow 


FUR  FIBERS 


235 


edge  projects,  and  the  upper  surface  of  the  bristle  appears  covered  with 
finely  waved  serrated  cross-lines.  The  cortical  layer  is  very  prominent, 
and  consists  of  very  thick-walled  elements,  whose  lumen  appears  full  of 
cracks.  In  cross-section  the  lumen  of  the  fiber  appears  like  a  short  thick 
line.  The  medulla  of  the  bristle  consists  of  thin-walled  parenchymous 
cells.     Here  and  there  appear  isolated  medullary  cells  enclosed  in  the 


1  2 

Fig.  115— Fur  Fibers.  (1)  Black  bear  (d  =  27n);  (2)  cat  (d-- 

(Hausman.) 


=  21m);  (3)  ermine  (^  =  17^). 


fibrous  mass.  The  bristles  found  in  trade  always  show  a  root.  They 
may  be  naturally  colored  white,  yellow,  red,  brown,  black,  or  gray,  or  they 
may  be  artificially  dyed.  The  pigment  is  found  in  the  form  of  fine 
granules,  especially  in  the  fibrous  elements,  and  more  frequently  on  the 
inside  than  on  the  outside  (Hohnel). 

13.  Fur  Fibers. — The  term  "  fur  "  is  usually  applied  to  the   pelts  of 
various  animals  with  the  hair  or  wool-like  covering  still  retained.     It 


4  5  6 

Fig.  116— Fur  Fibers.     (4)  Fitch    (^  =  18^);    (5)    red    fox,  Kolinsky   (d- 
Canada  lynx,  marten  (^  =  19^.)     (Hausman.) 


^19m);    (6) 


may  also  be  used,  however,  for  the  hair  by  itself,  removed  from  the  skin, 
as  for  example  when  employed  for  the  making  of  fur  felt  hats  and  the  like. 
Though  furs  in  the  form  of  pelts  can  hardly  be  regarded  in  the  sense  of 
textile  fibers  in  that  they  are  not  mechanically  processed  as  textiles, 
nevertheless  the  methods  of  treating  furs  are  such  that  thej^  may  be 
conveniently  considered  in  this  connection.  These  furs  are  treated  for 
purposes  of  dyeing,  bleaching,  and  finishing  in  much  the  same  manner  as 


236 


MINOR   HAIR  FIBERS 


wools  and  hairs  are  treated  in  the  making  of  textiles,  consequently  it  will 
not  be  out  of  place  to  give  them  some  consideration  in  the  present  volume. 
At  the  present  time  furs  are  more  or  less  "  manufactured,"  that  is  to 
say,  furs  of  one  animal  are  treated  in  such  a  manner  as  to  make  them 
closely  resemble  those  of  another  animal.     The  pelt  of  the  muskrat,  for 


Fig.  117.— Fur  Fibers.     (7)  Mink,  American  otter  (^  =  18^);    (8)  European  otter,  sea 

otter  (J  =  10m);    (9)  raccoon,  Russian  sable  (d  =  20/u.)  j 

example,  is  largely  processed  to  make  it  resemble  very  closely  the  fur  of  i 

the  rarer  and  more  expensive  seal,  giving  a  product  known  as  ''  Hudson  i 
seal."     The  following  table  gives  some  of  the  better-known  furs  and  their 

alteration  products.^  ! 


Actual  Fur. 
American  Sable 
Fitch,  dyed 
Goat,  dyed 
Hare,  dyed 
Kid 

Woodchuck  (Marmot) 
Mink,  dyod 
Muskrat,  dyod 
Muskrat,  pulled  and  dyed 
Nutria,  pulled  and  dyed 
Nutria,  pulled  natural 
Opossinn,  sheared  and  dyed 
Otter,  pulled  and  dyed 
Rabbit,  sheared  and  dyed 
Rabbit,  white 
Rabbit,  white,  dyed 
Kangaroo,  dyed 
Hare,  white 
Goat,  dyed 


Altered  to  Resemble 
Russian  Sable 
Sable 
Bear 

Sable  or  Fox 
Lamb 

Mink,  Sable,  Skunk 
SaVjle 

Mink,  Sable 
Seal 
Seal 

Beaver,  Otter 
Beaver 
Sable 

Seal,  Muskrat 
Ermine 
Chinchilla 
Skunk,  Marten 
Fox 
Leopard 


One  of  the  most  important  qualities  to  be  considered  in  reference  to  a 
fur  is  its  durability.  Though  this,  of  course,  is  dependent  to  a  considera])le 
degree  on  the  methods  employed  in  tanning  the  skin  and  in  processing  the 


^  Jones,  Fur  Farnmig  in  Canada. 


FUR  FIBERS  237 

fiber,  it  is  also  dependent  to  a  great  extent  on  the  nature  of  the  pelt  itself. 
The  following  table  gives  the  approximate  relative  durability  of  some 
of  the  common  furs  when  employed  for  outside  wear  •} 

„       .  Durability 

'^P®"^^-  (Otter  =  100). 

1.  Beaver 90 

2.  Bear,  black  or  brown 94 

3.  Chinchilla 15 

4.  Ermine 25 

5.  Fox,  natural 40 

6.  Fox,  dyed 20-25 

7.  Goat 15 

8.  Hare 5 

9.  Kolinsky 25 

10.  Leopard 75 

11.  Lynx 25 

12.  Marten  (skunk) 70 

13.  Mink,  natural 70 

14.  Mink,  dyed 35 

15.  Mole 7 

16.  Muskrat 45 

17.  Nutria  (Coypu  rat),  plucked 25 

18.  Otter,  sea 100 

19.  Otter,  inland , 100 

20.  Opossum 37 

21.  Rabbit 5 

22.  Raccoon,  natural 65 

23.  Raccoon,  dyed 50 

24.  Sable 60 

25.  Seal,  hair 80 

26.  Seal,  fur 80 

27.  Squirrel,  gray 20-25 

28.  Wolf 50 

29.  Wolverene 100 

In  their  physical  and  microscopical  characters  furs  are  very  similar  in 
general  to  wool  and  the  other  hair  fibers  which  have  already  been  con- 
sidered. As  a  rule  they  are  marked  by  the  occurrence  of  considerable 
pigment  matter  in  the  medulla,  and  this  may  occur  in  four  distinct  types: 
(1)  the  discontinuous  medulla,  as  in  the  duck-bill  or  platypus;  (2)  the 
continuous  medulla,  as  in  the  red  fox;  (3)  the  interrupted  medulla,  as  in 
the  hair  seal;  and  (4)  the  fragmental  medulla,  as  in  the  otter.  L,  A.  Haus- 
man  {Scientific  Monthly)  gives  the  following  method  for  the  microscopic 
examination  of  furs :  Several  hair  shafts  are  taken  and  washed  in  a  solution 
composed  of  equal  parts  of  95  percent  alcohol  and  ether  to  remove  any 
oily  matter  from  their  surface.  They  are  then  transferred  to  a  clean  glass 
slide,  covered  with  a  cover  glass,  and  allowed  to  stand  in  a  current  of  warm 
1  Peterson,  TJie  Fur  Trade  and  Fur  Bearing  Animals. 


238 


MINOR  HAIR  FIBERS 


air  until  thoroughly  dry.  Examination  can  now  be  made  directly  for 
those  hairs  whose  structural  elements  are  large  and  prominent,  such  as 
the  otter  and  beaver.     In  other  cases  the  hairs  must  be  washed  in  the 


10  11  12 

Fig.  118— Fur  Fibers.     (10)  Hair  seal  (d  =  105m);    (H)  skunk  W  =  26m);    (12)  wolver- 
ene ((i  =25  m)     (Hausman.) 

ether-alcohol,  as  before,  and  then  dipped  with  forceps  into  an  alcoholic 
solution  of  Gentian  Violet,  Methyl  Blue,  Methyl  Violet,  Bismarck  Brown, 


13  14  15 

Fig,  119.— Fur  Fibers.     (13)  Beaver  (.'/  =  18m);    (14)  chinchilla  ((l  =  lQfi)]    (15)  nutria, 

coney,  hare,  marmoset  ((l  =  llij..)     (Hausman.) 

or  Safranine.     This  treatment  renders  clear  the  outline  of  the  scales. 
The  following  micrographs  of  various  furs  have  been  adapted  from  Haus- 


16  17  18 

Fig.  120.— Fur  Fibers.       (16)   Gray  squirrel   (c?  =  18m);     (17)   rabbit   (^  =  17^);    (18) 
woodchuck  ((i  =  22yu.)     (Hausman.) 

man's  article  on  this  subject  (see  Figs.  115  to  127).  As  these  are  drawn 
to  the  same  size  instead  of  to  the  relative  diameters  of  the  fibers,  these 
latter  are  given  in  terms  of  microns. 


FUR  FIBERS 


239 


According  to  Hausman,  the  various  colors  of  animal  hairs  are  due  either 
to  pigment  materials  within  the  shaft,  or  to  coloring  matter  deposited  on 


19  20  21 

Fig.  121.— Fur  Fibers.     (19)  Muskrat  (^  =  17^);    (20)  European  mole  (d  =  17ai)  ;    (21) 
American  mole  (f/  =  17^i.)     (Hausman.) 

the  outside  of  the  cuticle,  and  may  be  modified  by  the  wa}^  in  which  the 
light  is  reflected  from  the  surfaces  of  the  various  structures  of  the  hair 


24 


22  23 

Fig.  122.— Fur  Fibers.     (22)  Koala  (d  =  22M);    (23)    opossum    (d=37fi);  (24)  duckbill 

(d  =  18/x.)     (Hausman.) 


shaft  itseK,     Hair  which  owes  its  hue  to  the  latter  cause  is  rare,  being  found, 
for  example,  on  the  flanks  and  base  of  the  tail  of  the  weasel.     In  the  gre::t 


Fig.  123.— Fur  Fibers.     (25)  Polar  bear  (^  =  52^);   (26)  black  bear  (^=46^);   (27)  squir- 
rel monkey  (d=47iu.)     Hausman.) 

majority  of  cases  it  is  the  presence  of  pigment  within  the  hair  shaft  that 
gives  color  to  the  hair. 

The  pigment  material  within  the  hair  shaft  may  be  diffuse,  i.e.,  not 


240 


MINOR  HAIR  FIBERS 


present  in  the  form  of  distinct  masses,  and  if  such  is  the  case  the  whole 
shaft  is  homogeneously  stained  and  the  hair  appears,  even  under  the 


28  29  30 

Fig.  124.— Fur  Fibers.     (28)  Blarina  {d=38fi);  (29)  sewellel  (^=25^);   (30)  guinea  pig 

((/  =  7Gju.)     (Hausman.) 

highest  powers  of  the  microscope,  as  a  uniformly  colored  structure.     Yellow 
or  amber  hairs  are  usually  pigmented  in  this  way. 


31  32  33 

Fig.  125.— Fur  Fibers.     (31)  Kangaroo  rat  (^  =  40^);    (32)  brown  bat   (^=8^);    (33) 
marmoset  {d  —  25ii.)     (Hausman.) 


The  most  common  cause  of  color  in  hair,  however,  is  not  external 
deposit,  or  internal  diffuse  stain,  but  the  presence  of  pigment  masses. 


34  35  36 

Fig.  126.— Fur  Fibers.     (34)  Badger  {d  =  57ti);   (35)  weasel  (d^lO/x);    (36)  blarina  tip 

{d  =  30jjL.)     (Hausman.) 


occurring  (1)  in  the  cortex  as  separate  granules,  or  (2)  in  the  medulla, 
usually  as  amorphous  masses,  though  sometimes  as  discrete  granules. 
The  hair  of  the  polar  bear  may  be  taken  as  typical  of  a  pure  white, 


FUR  FIBERS 


241 


i.e.,  colorless,  hair.  It  will  be  seen  that  no  pigment  is  present  in  the 
cortex  of  such  a  hair,  which  appears  under  the  microscope  as  a  transparent, 
glassy  shaft.  The  medulla  appears  to  be  dark  in  color.  This  is  due, 
possibly,  to  a  slight  amount  of  black  pigment  in  the  fused  medullary  cells, 
but  more  largely  to  the  dispersion  of  light  from  the  microscope  mirror. 

In  most  instances  the  colors  in  hair  are  produced  by  a  combination  of 
cortical  and  medullary  pigmentation,  sometimes  with  the  addition  of 
diffuse  color  as  well.  In  the  hair  of  the  black  bear,  for  example,  the 
color  is  due  to  very  dark  brown  cortical  granules,  plus  black  medullary 
masses.  Light  brownish  or  yel- 
lowish cortical  granules,  plus  dark 
brown  medullary  masses,  pro- 
duces dark  brown  fur,  as  in  the 
New  York  weasel  (Fig.  126,  No. 
35).  The  tip  of  the  fur  hair  of 
the  large  blarina  (Fig.  126,  No. 
36)  shows  the  usual  pigmenta- 
tion conditions  in  a  dark  grayish 
brown  hair,  i.e.,  black  medullary 
masses,  and  some  few  light 
brown  cortical    granules.      Hair 

from  the  squirrel  monkey  (Fig.  123,  No.  27)  and  marmoset  (Fig.  125, 
No.  33),  respectively,  illustrate  the  typical  conditions  found  in  yellow 
or  yellowish  hairs,  i.e.,  yellow  granules  both  in  medulla  and  cortex,  or 
yellow  granules  in  cortex,  and  yellow  masses  in  the  medulla. 

The  pigmentation  in  the  fur  hair  of  a  species  often  differs  from  that  in 
the  protective  hair.  There  is  likewise  a  change  in  the  character  of  the 
pigmentation  from  the  base  to  the  tip  of  both  varieties.  The  nature  of 
these  pigmentation  differences  in  the  hairs  of  the  same  animal  can  be  well 
illustrated  from  the  hair  of  the  muskrat. 


37 

Fig.  127— Fiir  Fibers.  (37)  Prairie  dog  (d  = 
50m);  (38)  cotton-tail  rabbit  (^  =  10^.) 
(Hausman.) 


CHAPTER  IX 
SILK:    ITS  ORIGIN  AND  CULTIVATION 

1.  Origin  of  Silk  Fiber. — The  silk  fiber  consists  of  a  continuous  thread 
which  is  spun  by  the  silkworm.  The  worm  winds  the  fiber  around  itself 
in  the  form  of  an  enveloping  cocoon  before  it  passes  into  the  chrysalis 
or  pupal  state.  The  cocoon  is  ovid  in  shape  and  is  composed  of  one 
continuous  fiber,  which  varies  in  length  from  350  to  1200  meters  (400  to 
1300  yds.),  and  has  an  average  diameter  of  0.018  mm.  In  the  raw  state 
the  fiber  consists  of  a  double  thread  cemented  together  by  an  enveloping 
layer  of  silk-glue,  and  is  yellowish  and  translucent  in  appearance.  When 
boiled  off  or  scoured  these  double  threads  are  separated,  and  the  silk  then 
appears  as  a  single,  lustrous,  and  almost  white  fiber. 

Unlike  both  wool  and  cotton,  silk  is  not  cellular  in  structure,  and  is 
apparently  a  continuous  filament  devoid  of  structure.  Hohnel,  however, 
believes  that  the  silk  fiber  is  not  so  simple  in  structure  as  would  at  first 
be  believed.  The  surface  of  the  fiber  frequently  shows  faint  striations, 
which  may  be  rendered  more  apparent  by  treatment  with  chromic  acid. 
Also  by  saturating  the  silk  with  moderately  concentrated  sulfuric  acid  and 
drying,  then  heating  to  80°  to  100°  C,  the  fiber  will  be  disintegrated  into 
small  filaments,  which  would  seem  to  indicate  that  it  was  made  up  of  a 
number  of  minute  fibrils  firmly  held  together. 

The  silk  industry  is  divided  into  a  number  of  independent  enterprises: 

(a)  Sericulture,  which  has  to  do  with  the  growth  and  cultivation  of 
the  silkworm  and  the  cocoon. 

(6)  Silk-reeling,  in  which  the  silk  thread  is  wound  from  the  cocoon 
into  skeins  known  as  raw  silk  of  trade. 

(c)  Throwing,  which  takes  the  raw  silk  and  converts  it  into  suit- 
able yarns  for  manufacturing  purposes.  The  operator  is  known  as  a 
"  throwster." 

(d)  Manufacturing,  in  which  the  thrown  silk  is  made  into  various 
fabrics  by  weaving,  knitting,  braiding,  etc.,  and  also  bleached,  dyed, 
and  weighted. 

It  seldom  happens  that  any  of  these  groups  overlap  in  the  same 
factory,  Init  each  operation  is  carried  out  as  a  separate  industry. 

2.  History  of  Silk  Culture. — The  silk  industry  appears  to  have  had  its 
origin  in  China,  and  historically  it  dates  back  to  about  2700  years  B.C. 

242 


HISTORY  OF  SILK  CULTURE 


243 


In  its  early  history  it  is  said  that  the  art  of  cultivating  the  silkworm  and 
preparing  the  fiber  for  use  was  a  strictly  guarded  secret"  known  only  to  the 
royal  family.  Gradually,  however,  it  spread  through  other  circles  and 
soon  became  an  important  industry  distributed  universally  throughout 
China.  The  Chinese  monopolised  the  art  for  over  three  thousand  years, 
but  during  the  early  period  of  the  Christian  era  the  cultivation  of  the  silk- 
worm (or  sericulture)  was  introduced  into  Japan.  It  also  gradually  spread 
throughout  central  Asia,  thence  to  Persia  and  Turkey.  In  the  eighth 
century  the  Arabs  acquired  a  knowledge  of  the  silk  industry,  which  soon 
spread  through  all  the  countries  influenced  by  the  Moorish  rule,  including 
Spain,  Sicily,  and  the  African  coast.  In  the  twelfth  century  we  find 
sericulture  practiced  in  Italy,  where  it  slowly  developed  to  a  national 


Fig.  128— The  Silkworm.     (1)  Head;    (2-10),  (12)  rings;    (11)  horn;    (13)  articulated 
legs;   (14)  abdominal  or  false  legs;   (15)  false  legs  on  last  ring. 


industry.  In  France  sericulture  appears  to  have  been  introduced  about 
the  thirteenth  century,  but  it  was  not  until  the  reign  of  Louis  XIV  that 
it  assumed  any  degree  of  importance.  In  more  recent  times  experiments 
have  been  made  on  the  cultivation  of  the  silkworm  in  almost  every  civilised 
country.^ 

Mr.  Samuel  Whitmarsh,  about  1838,  made  an  attempt  to  introduce 
sericulture  in  America.  He  cultivated  the  South  Sea  Island  mulberry 
{Motus  multicaulis)  in  Pennsylvania,  but  the  experiment  proved  to  be  a 
failure.  Previous  to  this  time  there  had  been  various  sporadic  attempts 
toward  sericulture  in  America,   and  bounties  were  offered  by  various 

1  The  word  silk,  as  expressed  in  different  languages,  is  as  follows: 


Korean 

Sir 

Danish 

Silcke 

Chinese 

Se 

Anglo-Saxon 

Siolc 

Mongol 

Sirkek 

English 

Silk 

Armenian 

Cherani 

Italian 

Seta 

Arabic 

Seric 

German 

Seide 

Latin 

Sericum 

French 

Soie 

Slavonian 

Chelk    • 

244  SILK:    ITS  ORIGIN  AND  CULTIVATION 

States.  In  1619  bounties  were  offered  to  Virginia  settlers,  and  later 
Franklin  at  Philadelphia  reared  quite  a  promising  filature.  In  later  years 
there  have  been  many  attempts  to  introduce  the  industry  of  sericulture 
into  the  United  States,  and  it  has  been  satisfactorily  demonstrated  that 
good  silk  can  be  raised  in  this  country,  more  especially  in  the  Southern 
States.  The  failure  of  the  industry  has  not  been  due  to  lack  of  proper 
climatic  conditions,  but  simply  to  the  high  cost  of  labor  as  compared  with 
Oriental  labor.  Even  in  1921  it  was  reported  that  silk  was  being  grown 
in  southern  California,  and  the  claims  were  made  that  it  would  be  possible 
to  produce  sufficient  silk  to  cover  the  demands  of  America  more  profitably 
than  by  importing,  notwithstanding  the  cheap  Eastern  labor.  It  is  said 
that  the  climate  of  the  foothills  of  the  Sierras  inhibits  silkworm  diseases 
and  that  the  fiber  is  longer  and  more  lustrous  than  the  Japanese.  With 
the  elevation  of  labor  costs  in  the  Orient  it  may  be  quite  possible  in  time 
to  establish  sericulture  on  a  profitable  scale  in  America.^  With  respect  to 
the  amount  of  raw  material  consumed,  the  United  States  stands  first 
among  the  silk  manufacturing  countries  of  the  world. 

3.  The  Silkworm. — The  silkworm  is  a  species  of  caterpillar,  and  though 
there  are  quite  a  number  of  the  latter  which  possess  silk-producing  organs, 
the  number  which  secrete  a  sufficient  quantity  of  the  silk  substance  to 
render  them  of  commercial  importance  is  rather  limited.  The  true  silk- 
worms all  belong  to  the  general  class  Lepidoptera,  or  scale-winged  insects, 
and  more  specifically  to  the  genus  Bomhyx.  The  principal  species  is  the 
Bomhyx  mori,  or  mulberry  silkworm,  which  produces  by  far  the  major 
portion  of  the  silk  that  comes  into  trade.^ 

According  to  the  number  of  the  generations  they  produce  in  a  year, 
the  Bomhyx  mori  are  divided  into  two  classes:  the  members  of  the  one 
reproduce  themselves  several  times  annually,  and  are  termed  polyvoltine; 
their  cocoons  are  small  and  coarse.  The  other  worms  have  only  one 
generation  in  a  j^ear,  and  hence  are  termed  annual.  The  cocoons  of  the 
latter  are  much  superior  to  those  of  the  former. 

There  are  two  kinds  of  silkworm  culture:   One  for  production  and  one 

1  Balbiani  {Bull.  des.  Soies  et  Soieries,  1921,  p.  5)  calls  the  attention  of  the  Italian 
and  the  French  silk  world  to  the  establishment  of  silk  raising  in  California.  So  suc- 
cessful, he  says,  have  been  the  experiments  on  the  Pacific  Coast  that  a  company  with 
a  capital  of  $300,000  has  been  formed  to  continue  them.  A  tract  of  land,  amounting 
to  about  800  acres,  has  been  acquired  at  Oroville,  Butte  County,  near  Sacramento, 
for  a  mulberry  plantation.  He  considers  the  samples  to  be  equal  to  the  best  Italian, 
a  view  shared  by  some  experts  in  the  East.  The  company  is  believed  to  be  employing 
Japanese  instructors  and  is  building  a  filature  of  80  basins.  In  view  of  these  develop- 
ments, he  urges  Italian  silk  growers  to  encourage  the  production  of  silk  in  all  directions 
in  order  to  raise  the  industry  to  its  former  state. 

2  Wardle  (Tussur  Silk,  p.  40)  gives  a  list  of  several  hundred  species  of  Lepidoptera 
that  yield  silk. 


THE  SILKWORM 


245 


for  breeding.  The  object  in  the  first  case  is  to  get  the  greatest  yield  of 
cocoons,  and  with  a  httle  training  this  enterprise  may  be  carried  on  by 
any  one  of  ordinary  intelHgence.  The  object  in  culture  for  breeding  is  to 
secure  eggs  free  from  hereditary  taint  of  disease,  and  experts  only  can  be 
depended  on  for  this  culture.  Besides  a  careful  physiological  examination 
throughout  the  rearing,  the  body  of  the  mother  moth  is  microscopically 
tested  after  death,  and  her  eggs  are  not  retained  if  signs  of  disease  are 
discovered.  In  this  way  the  birth  of  healthy  worms  is  insured.  Pasteur 
first  appUed  this  method  of  selecting  silkworm  eggs,  and  thus  checked 


Fig.  129. — Showing  Different  Stages  in  Growth  of  Silkworm.  A,  Silkworm  in  fifth 
period,  full  size;  B,  moth  or  butterfly;  C,  chrysalis,  or  pupa;  D,  eggs  of  moth; 
E,  diagram  showing  cocoon  and  method  of  winding. 


the  plague  (pebrine)  which  was  rapidly  destroying  silkworm  culture  in 
Europe. 

The  cultivation  of  the  silkworm  starts  with  the  proper  care  and  disposi- 
tion of  the  eggs.  With  the  annual  worms  there  elapse  about  ten  months 
between  the  time  the  eggs  are  laid  and  their  hatching.  The  hatching  only 
takes  place  after  the  eggs  have  been  exposed  to  the  cold  for  some  time 
and  are  subsequently  subjected  to  the  influence  of  heat.  When  the  eggs 
are  laid  by  the  silk-moth  they  are  received  on  cloths,  to  which  they  stick 
by  virtue  of  a  gummy  substance  which  encloses  them.  For  the  first 
few  days  they  are  hung  up  in  a  room,  the  air  of  which  is  kept  at  a  certain 


246 


SILK:    ITS   ORIGIN   AND   CULTIVATION 


Fig.  130. — Section  through  the  Silkworm. 


degree  of  humidity — about  semi-saturation.  Then  comes  a  period  of 
hibernation,  during  which  the  eggs  are  kept  in  a  cool  place;  at  present 
artificial  refrigeration  is  resorted  to  in  many  establishments.  The  period 
of    hibernation     lasts 

about  six  months.  After       -  .^;^^ss?^==^  i 

this  comes  the  period 
of  incubation,  in  which 
the  embryo  is  gradu- 
ally developed  into  a 
worm    and    the  egg  is 

hatched.  The  hatching  usually  takes  place  in  heated  compartments, 
in  which  the  temperature  is  carefully  regulated.  The  period  of  incu- 
bation occupies  about  thirty  days,  though  this  time  has  been  shortened 
considerably  by  certain  artifices,  such  as  the  action  of  electric  discharges. 
Twenty-five  grams  of  eggs  will  yield  about  36,000  worms 
on  hatching. 

The  caterpillar,  on  first  making  its  appearance,  is 
about  3  mm.  long,  and  weighs  approximately  0.005  gram. 
Its  growth  and  development  proceed  with  extraordinary 
rapidity,  and  during  its  short  existence  it  undergoes  a 
number  of  very  curious  transformations.  Under  normal 
conditions  there  elapse  thirty-three  to  thirty-four  days 
between  the  time  of  the  hatching  of  the  egg  and  the 
commencement  of  the  spinning  of  the  cocoon.  During 
this  time  the  worm  sheds  its  skin  four  times,  and  these 
periods  of  moulting  divide  the  life-history  of  the  worm 
into  five  periods.  The  length  of  time  occupied  in  these 
different  ages  approximates  as  follows: 

1st,  from  birth  to  first  moult,  5  to  6  days. 

2d,  from  first  to  second  moult,  4  days. 

3d,  from  second  to  third  moult,  4  to  5  days. 

4th,  from  third  to  fourth  moult,  5  to  7  days. 

5th,  from  fourth  moult  to  maturity,  7  to  12  days. 

Almost  immediately  after  being  hatched  the  worms 

p,  ,      .„,   a-iu    commence  to  devour  mulberry  leaves  with  great  avidity, 

producing  Gland  ^^^^^  continue  to  eat  throughout  the  five  periods,  though, 

of  the  Silkworm,    when  about  to  shed  their  skins,  they  stop  eating  for  a 

time  and  become  motionless. 

The   size  and   weight   of  the   caterpillars  increase   with  remarkable 

rapidity;    during  the  fifth  period  they  reach  their  greatest  development, 

measuring  from  8  to  9  cm.  in  length  (Fig.  128)  and  weighing  from  4  to  5 

grams,  and  after  thus  maturing  they  begin  to  diminish  in  weight.     The 

following  table  by  Vignon  shows  the  relative  weights  of  the  silkworm 


THE   SILKWORM 


247 


during  the  different  stages  of  its  existence, 
of  36,000  worms. 


The  figures  refer  to  the  weight 


Grams. 

Eggs 25 

Worms  (36,000) 17 

First  period  (5  to  6  days) 255 

Second  period  (4  to  5  days) 1,598 

Third  period  (6  to  7  days) 6,800 

Fourth  period  (7  to  8  days) 27,676 

Fifth  period  (11  to  12  days) 161,500 

At  maturity 131,920 

Cocoons 76,250 

Chrysalis  alone 66,300 

Butterflies,  half  of  each  sex 99,865 

Thus  we  see  that  in  less  than  forty  days  the  weight  of  the  silkworm 
increases  almost  10,000  times. 

According  to  Arbousett  1  oz.  of  silkworm  seed  (eggs)  produces  about 
30,000  silkworms,  and  these  will  yield  a  harvest  of  130  to  140  lbs.  of  fresh 
cocoons,  giving  an  ultimate  yield  of  about  12  lbs.  of  reeled  raw  silk.  These 
worms  in  their  growth  consume  about  1  ton  of  ripe  mulberry  leaves. 

When  the  worm  has  reached  the  limit  of  its  growth,  it  ceases  to  eat, 
and  commences  to  diminish  in  size  and  weight.  The  time  is  now  ready 
for  the   spinning  of  its  cocoon; 

the  worm  perches  on  the  twigs  e  d  [\\^ c  f, 

so  disposed  to  receive  it  and 
exudes  a  viscous  fluid  from  the 
two  glands  in  its  body  wherein 
the  silk  secretion  is  formed.  The 
liquid  flows  through  two  channels 
in  the  head  of  the  worm  into  a 
common  exit-tube,  whei'e  also 
flows  the  secretion  of  two  other 
s>Tnmetrically     situated     glands 

which  cements  the  two  threads  together.  Consequently,  the  thread  of 
raw  silk  is  produced  by  four  glands  in  the  worm;  the  two  back  ones 
secrete  the  fibroine  which  gives  the  double  silk  fiber,  while  the  two  front 
glands  secrete  the  silk-glue  or  sericine  which  serves  as  an  integument 
and  cementing  substance.  On  emerging  from  the  spinneret  in  the  head  cf 
the  worm  the  fiber  coagulates  on  contact  with  the  air. 

According  to  BoUey  the  glands  in  the  silkworm  which  secrete  the  fiber- 
producing  liquids  contain  only  glutinous,  semi-fluid  fibroine  withoi  t 
admixture  with  sericine,  the  latter  compound  being  a  product  of  the 
subsequent  oxidation  of  the  fibroine  by  the  air. 


Fig.  132. — Outside  Appearance  of  Spinneret  of 
Silkworm. 


248 


SILK:    ITS  ORIGIN  AND  CULTIVATION 


The  viscous  liquid  in  the  glands  of  the  silkworm  is  utilised  in  a  peculiar 
manner  for  the  preparation  of  silkworm  gut  for  fishing  lines,  or  for  other 
such  purposes  where  lightness,  tenacity,  flexibility,  and  great  strength 
are  essential.  The  fully  developed  larvae  are  killed  and  hardened  by  steep- 
ing for  several  hours  in  acetic  acid ;  the  glands  are  then  removed  and  their 
viscous  contents  are  drawn  out  to  a  fine  uniform  line  which  is  stretched 
between  pins  on  a  board.  This  is  then  exposed  to  sunlight  until  the 
lines  dry  into  the  condition  of  gut.  This  is  a  rather  unimportant,  though 
interesting  collateral  branch  of  silk  manufacture. 

The  contents  of  the  glands  of  the  silkworm  have  been  the  subject  of 
study  in  a  peculiar  manner  by  Chappe.     He  triturated  the  glutinous  matter 
with  about  one-third  its  weight  of  water,  and  thus  obtained  a  licjuid  from 
,  which  he  was  enabled  to  blow  vari- 

ously shaped  vessels  of  a  very  per- 
manent character. 

A  rather  unusual  silk  fiber  is 
that  known  as  "Fil  de  Florence"; 
it  is  said  to  have  been  known  in 
China  from  a  very  early  date, 
though  first  mentioned  in  Europe 
in  1760.  The  fiber  is  not  prepared 
from  the  cocoon  of  the  silkworm, 
but  from  the  silk-containing  organs 
of  the  worm  itself.  The  worm  is 
soaked  in  acetic  acid,  opened,  and 
the  silk  glands,  which  are  about 
2  ins.  long,  are  removed.  These 
are  stretched  while  soft  to  a  length 
of  about  15  to  20  ins. 
4.  The  Cocoon. — The  worm  weaves  the  thread  around  itself,  layer 
after  layer,  until  the  cococn  or  shell  is  graduall}''  built  up.  It  requires 
about  three  days  for  the  completion  of  the  cocoon.  First  a  net  is  formed 
to  hold  the  cocoon  which  is  to  be  spun,  then  the  regular  spinning  begins 
and  the  form  of  the  cocoon  is  designed.  It  is  calculated  that  with  its  head 
alone  the  silkworm  makes  69  movements  every  minute,  describing  arcs  of 
circles,  crossed  in  the  form  of  the  figure  8.  Meanwhile  the  web  grows 
closer  and  the  veil  thickens,  and  in  about  72  hours  the  worm  is  completely 
shut  up  in  its  cocoon,  which  serves  it  as  a  protective  covering. 

After  finishing  the  winding  of  its  cocoon,  the  enclosed  silkworm  under- 
goes a  remarkable  transformation,  passing  from  the  form  of  a  caterpillar 
into  an  inert  chrysalis  or  pupa,  from  which  condition  it  rapidly  develops 
into  a  butterfly,  which  then  cuts  an  opening  through  the  cocoon  and  flies 
away.     The  worm  in  spinning  the  cocoon  leaves  one  end  less  dense,  so 


Fig.  133.  Fig.  134. 

Fig.  133. — Silkworm  at  Completion  of  Co- 
coon. 

Fig.  134. — After  Development  of  Chrysalis 
with  Cast-off  Skin  of  Larva  Beneath. 


THE   COCOON   THREAD 


249 


that  the  threads  open  freely  to  permit  the  egress  of  the  moth.  By  the 
aid  of  an  alkahne  fluid  the  moth  softens  and  parts  the  threads  and  hberates 
itself. 

As  the  integrity  of  the  cocoon  thread  would  be  destroyed  by  the  escape 
of  the  butterfly  and  hence  lose  much  of  its  value,  it  is  desirable  that  the 
development  of  the  chrysalis  be  stopped  before  it  proceeds  too  far,  and 
this  is  accomplished  by  killing  it  by  a  heat  of  from  70°  to  80°  C.  or  by  live 
steam.  The  cocoons  at  this  stage  weigh  from  1.25  to  2.5  grams  each, 
and  of  this  15  to  16  percent  is  silk  fiber.  The  proportion  of  silk  in  a  cocoon 
varies  according  to  the  race  and  also  to  the  regimen  to  which  the  worm 
has  been  subjected.  The  average  normal  cocoon  at  the  time  it  is  sold  is 
thus  composed: 

Percent. 

Water 68.2 

Silk 14.3 

Web  and  veil 0.7 

Chrysalis 16.8 

However,  only  8  to  10  percent  is  available  for  silk  filaments,  the  re- 
mainder, 6  to  7  percent,  constituting  waste  and  broken  threads,  and  is 
utilised  for  spun  silk. 

As  to  the  thickness  of  the  filaments  of  silk  in  the  cocoon,  Haberlandt 
furnishes  the  following  data: 


Species. 


Yellow  Milanais 
Yellow  French .  . 
Green  Japan . .  .  . 
White  Japan . . .  , 
Bivoltin  worms. 


Exterior  Layer 
of  Cocoon. 


0,030  mm. 
0.025    " 
0.030    " 
0.020    " 
0.025    " 


Middle 
Layer. 


0.040  mm. 
0.0:35    " 
0.040    " 
0.030    " 
0.035    " 


Interior 
Layer. 


0.025  mm. 
0.025    " 
0.020    " 
0.017    " 
0.020    " 


6.  The  Cocoon  Thread.^The  double  silk  fiber  as  it  exists  in  the  cocoon 
is  known  as  the  have,  and  the  single  filaments  are  called  brins.  These 
terms  are  not  common  in  the  American  trade,  where  the  unprocessed 
cocoon  thread  is  seldom  used;  they  are  mostly  to  be  found  in  the  trade 
parlance  of  the  European  silk  industry.  The  size  of  the  double  silk  fiber 
as  it  comes  from  the  cocoon  averages  2|  to  3  deniers.  The  following 
table  gives  the  approximate  size  of  cocoon  threads  of  mulberry  silk  from 
different  countries: 


250 


SILK:    ITS   ORIGIN   AND   CULTIVATION 


Spain.  .  . 
France. . 
Italy.... 
Syria.  .  .  , 
Caucasus 
Broussa . 
Japan . . . 
China. . . 
BengaL  . 


Weight  of  500  Meters. 


In 

In 

Deniers. 

Milligrams. 

3.0 

163 

2.6 

138 

2.4 

128 

2.4 

128 

2.3 

125 

2.2 

117 

2.1 

113 

2.0 

108 

1.2 

64 

The  single  silk  filament  in  the  double  cocoon  thread,  therefore,  is  about 
Ij  to  1^  deniers  in  size. 

According  to  the  Lyons  Conditioning  House,  the  average  size  of  cocoon 
threads  is  given  as  follows : 

Deniers. 

Yellow  Piedmont 3.06 

' '       Cevennes 3 .  03 

White  Persians 2 ,  87 

Yellow  Adrianople 2 .  84 

"       Tuscan 2.81 

' '       Salonika 2 .  73 

"       Greece 2.61 

' '       Hungarian ' 2 .  64 

White  Turkestan 2.68 

' '      Japanese 2.12 

' '      Chinese 1 .  96 


The  highest  grade  of  silk  is  the  white  or  yellow  Italian  silk  raised  in 
Piedmont,  together  with  the  best  China  silks  reeled  in  steam  filatures. 
The  next  grade  is  the  best  Japan  silk.  There  is,  however,  much  low- 
grade  silk  sent  out  of  Italy.  Most  of  the  cocoons  grown  in  Asia  Minor 
and  Turkey-in-Europe  are  sent  to  Italy  for  reeling.  The  French  Cevennes 
silks  are  of  good  quality  but  are  more  hairy  in  nature  than  generally 
desirable.  Canton  silks  come  from  South  China,  and  are  soft,  lustrous, 
and  very  hairy,  on  which  last  account  their  use  is  rather  limited.  Wliite 
China  silks  reeled  in  the  native  fashion  are  known  as  Tsatlees  and  are  too 
irregular  to  be  generally  useful.  Both  Tsatlees  and  Cantons  are  difficult 
to  throw  and  the  throwing  cost  is  5  to  10  cents  per  pound  higher  than  for 
ordinary  silks. 


THE   COCOON   THREAD 


251 


Bengal  (Indian)  silk  is  of  poor  quality  and  is  only  used  for  certain  special 
purposes,  such  as  for  the  making 
of  silk  hats   and  for   some  quali- 
ties of  sewing  threads. 

Chittick  {Silk  Manufacturing, 
p.  18)  points  out  that  some  silks 
have  adherent  disadvantages  about 
them  which  must  be  remembered 
when  considering  the  price.  Thus 
Tsatlees,  owing  to  their  great  ir- 
regularity in  size  and  to  the  way  in 
which  they  are  generally  reeled, 
not  only  cost  more  for  throwing 
and  in  waste,  but  may  require 
the  use  of  more  weight  of  mate- 
rial to  give  the  proper  cover. 
The  amount  of  boil-off  of  the 
silk  is  also  to  be  wtII  considered, 
particularly  in  fabrics  for  piece 
dyeing,  as  it  makes  quite  a  differ- 
ence whether  the  silk  boils  off  24 
percent,  as  in  the  case  of  yellow 
Italian,  or  18  percent,  as  in  the  case  of  Japanese  silks. 

Murphy  (Textile  Industries,  p.  63)  gives    the  following  table  relative 
to  different  varieties  of  silk: 


Fig.  135.— The  Silk-moth. 
a,  Male;  b,  female. 


Silkworm. 

Country. 

Diameter  of 

Fiber, 
1/1000  Ins. 

Tensile 

Strength, 

Drams. 

Feed. 

Color. 

Size  of 
Cocoons, 

Outer. 

Inner. 

Outer. 

Inner. 

Ins. 

Bombyx  mori 

B.  mori 

B.  mori 

B.  fortunatus 

B.  textor 

Anth.  mylitto 

Attacus  ricinus .... 

A.  cynthia 

A.  atlas 

Actias  selene 

Anth.  pernyi 

Yama-mai 

China 

Italy 

Japan 

Bengal 

India 

China 
.lapan 

53 

53 

57 

45 

42 

161 

85 

83 

102 

100 

118 

88 

71 

68 

69 

51 

47 

172 

93 

97 

111 

109 

138 

96 

1.6 
1.9 
2.0 
1.6 
1.4 
6.6 
1.5 
2.4 
2.1 
2.4 
3.2 
6.8 

2.6 
2.6 
3.1 
2.8 
2.6 
7.8 
3.0 
3.5 
4.1 
4.0 
5.8 
7.5 

Mulberry 

Seemul 

Castor  oil  tree 

A.  glandulosa 

Omnivorous 

Cherry 

Oak 

Wild  oak 

White 

Golden  yellow 

White 

Brown 

Orange 

Yellowish 

White 

Grayish 

Brown 

Bluish 

1.1X0.5 
1.2X0.6 
1.1X0.6 
1.2X0.5 
1.2X1.5 
1.5X0.8 
1.5X0.8 
1.8X0.8 
3.5X0.8 
3.0X1.2 
1.6X0.8 
1.5X0.5 

252 


SILK:     ITS   ORIGIN   AND   CULTIVATION 


Raw  silk  is  classified  on  the  New  York  market  as  follows: 


European  silks: 

Grand  Extra 

Best  No.  1 

Extra  Classical 

No.  1 

Best  Classical 

Realine 

Classical 

Japan  silks: 

Filature. 

Re-reels. 

Kakeda. 

Double  Extra 

Extra 

Best  Extra 

Extra 

No.  1 

Extra 

Sinshiu  Extra 

No.  1-U 

No.  1 

Best  No.  1,  Extra 

No.  U 

No.  2 

Best  No.  1 

No.  11-2 

No.  3 

Hard  Nature  No.  1 

No.  2 

No.  1,  Summer  Reeling 

No.  2-2i 

No.  1-1 1 

No.  21 

No.  U 

No.  3 

No.  li-2 

No.  2 

Japan  silk  is  not  as  white  in  color  as  China  silk;  in  the  low  grades  it 
is  more  or  less  streaky  and  discolored,  which  is  apt  to  cause  shadiness  in 
the  dyed  piece.  The  strength  and  elasticity  vary  widely;  the  brilliancy  is 
as  good  as  that  of  Chinese  silk  or  the  high-class  European  silks.  Japanese 
silks  are  also  distinctly  irregular  in  size  as  compared  with  the  better 
qualities  of  European  silks. 

6.  Waste  Silk. — There  are  several  different  varieties  of  waste  silk,  as 
follows : 

1.  The  refuse  obtained  in  raising  the  silkworm,  called  watt  silk  in  commerce. 
Owing  to  the  scientific  methods  of  silk-culture  in  Europe,  the  amount  obtained  from 
this  source  is  very  small.  China,  however,  exi^orts  a  large  amount  j^early.  This 
material  contains  about  35  percent  of  pure  silk,  and  is  the  poorest  grade  of  waste  silk 
on  account  of  its  irregularity. 

2.  The  irregularly  spun  and  tangled  silk  on  the  outside  of  the  cocoon,  called  floss 
silk  or  frisons.  It  comprises  from  25  to  30  percent  of  the  entire  cocoon,  and  is  valuable 
owing  to  its  purity  and  fine  quality. 

3.  The  residue  of  the  cocoon  after  reefing;  this  forms  an  inner  parchment-like 
skin,  and  in  commerce  goes  under  the  name  of  ricotti,  wadding,  neri,  galettame, 
basinetto,  etc. 

4.  Cocoons  imperfect  from  various  causes,  such  as  being  punctured  by  the  worms, 
becoming  spotted  by  pupa  breaking,  etc.  These  are  known  as  cocoons,  perces,  piques, 
tarmate,  rugginose,  etc.     It  forms  a  valuable  material  for  floss-silk  spinning. 

5.  Double  cocoons,  which,  in  spite  of  the  difficulty  in  reeling,  were  formerly  used 
for  special  purposes.  Now  such  cocoons  are  converted  into  waste  which  is  known  as 
strussa. 

6.  Waste  obtained  in  reeling  the  cocoons,  known  as  frisonnets. 

7.  A  great  variety  of  wild  silks,  which,  for  the  most  part,  cannot  be  reeled,  and 
are,  therefore,  first  converted  into  waste.  A  large  quantity  of  wild  silk,  even  though 
it  can  be  reeled,  is  torn  up  for  waste. 


WASTE  SILK  253 

8.  Waste  made  by  throwing,  spooling,  and  other  processes  of  working  silk.  The 
waste  in  throwing  varies  with  the  character  of  the  raw  silk.  According  to  Chittick, 
the  following  wastage  is  to  be  expected : 

Percent. 

Regular  organzine 1 .  75-2 .  50 

Regular  tram 1.75-3.00 

Canton  tram 4.25-6.00 

Crack  tussah  chops 3 .  50 

Lower  grade 5 .  00 

Press-packed  tussahs 7 .  50-10 .  00 

Crepe  twists 2.00-  3.00 

Tsatlees 3.00-  5.00 

Armitage  {Textile  Manufacturer)  states  that  for  practical  purposes  all 
the  waste  silk  that  can  be  used  by  a  spinner  may  be  classed  under  two 
heads:  gum  wastes  and  knub  wastes.  Gum  waste  is  the  product  of  the 
reeler  and  thrower  of  nett  silk.  The  best  classes  of  cocoon  are  reeled  and 
thrown,  and  it  follows  that  the  waste  produced  is  the  best  waste.  It  is 
long,  strong,  and  lustrous.  Knub  waste  consists  largely  of  that  part  of 
the  cocoon  which  is  considered  to  be  of  too  poor  a  quality  to  reel;  also 
the  outer  covering  and  the  inner  shell  of  the  cocoon  are  of  poorer  quality 
than  the  intermediate  part. 

Foremost  among  gum  wastes  must  be  placed  what  is  known  as  China 
waste.  It  is  of  three  grades — English,  French,  and  Italian.  It  is  obtained 
from  China  raw  silk,  and  is  named  according  to  the  country  in  which  the 
silk  is  thrown.  French  and  Italian  China  are  best.  The  English  differs 
fi-om  the  French  and  Italian  in  the  particular  that  the  English  throwsters 
soap  their  nett  silk  in  throwing;  hence  the  waste  is  of  duller  appearance, 
and  contains  a  percentage  of  soap,  which  gives  it  the  appearance  of  inferi- 
ority, as  against  the  bright  and  clear  product  of  the  French  and  Italian 
throwster.  The  chief  excellences  of  China  waste  are  whiteness,  brightness, 
length,  and  strength  of  fiber.  It  is  especially  valuable  for  spinning  the 
finest  counts,  such  as  120-2  and  100-2. 

Nankin  buttons  is  another  waste  of  merit.  It  is  a  product  of  Central 
China.  It  derives  its  name  from  the  fact  that  it  contains  a  proportion  of 
matted  silk  formed  so  as  to  appear  similar  to  a  button.  It  is  white  and 
bright,  but  irregular  in  length  and  is  subject  to  hard  ends,  which  are  so 
tightly  twisted  together  that  they  cannot  be  split  into  fiber  and  dressed 
and  drawn  as  the  spinner  desires. 

Shanghai  waste  is  another  gum  waste  that  is  largely  used.  It  is  in  two 
grades — fine  and  coarse,  white  and  yellow.  The  white  is  mostly  used, 
and  is  shipped  as  Hangchow,  Chintzar,  etc.  It  is  excellent  waste,  but  not 
so  good  in  color  as  China  or  Nankin,  and  is  much  more  liable  to  impurities. 
Yellow  Piedmont  and  Italian  wastes  are  also  largely  used.     They  are 


254  SILK:     ITS   ORIGIN   AND   CULTIVATION 

bright  and  strong,  and  usually  free  from  objectionable  matter,  but  produce 
a  creamy  colored  yarn. 

French  gray  and  yellow  waste  have  great  merit.  Either  yields  well,  is 
bright  and  long,  but  is  invariably  subject  to  cotton  ends.  These  in  the 
course  of  subsequent  processes  are  broken  up,  and  the  result  is  disastrous. 
When  the  yarn  leaves  the  dyer  it  is  specky  and  flecky;  the  cotton  shows 
white,  and  unsatisfactory  goods  are  the  result. 

Canton  gum  re-reeled  is  a  waste  of  great  luster,  but  in  other  respects  is 
not  so  good  as  the  before-mentioned  wastes.  It  is  made  from  Canton  raw 
silks  that  are  re-reeled  in  order  to  take  out  the  thick  and  uneven  places 
left  in  the  silk  at  the  first  reeling.  Canton  gum  is  a  fairly  bright  waste, 
but  is  subject  to  twisted  ends,  hemp  and  black  hairs,  and  can  be  used 
only  for  low-class  yarns. 

Punjuni  waste  is  a  peculiar  waste  of  great  strength  and  luster.  It  is 
produced  from  cocoons  of  coarse  and  uneven  texture,  and  in  reeling  the 
ends  off,  from  6  to  12  cocoons  are  taken  up  and  reeled  together,  no  attention 
being  given  to  straightness.  It  is  very  heavily  gummed,  in  some  cases 
to  the  extent  of  50  percent. 

Indian  gum  wastes  are  the  despair  of  the  spinner.  They  contain  good, 
fine  waste  mixed  with  the  coarsest  qualities  produced.  They  contain 
about  10  percent  cotton,  twist,  hairs,  string,  and  other  abominations. 

Steam  waste  is  the  finest  and  best  knub  waste,  and  is  the  foundation 
waste  of  the  spinner.  It  is  imported  in  various  grades,  and  in  two  distinct 
sorts:  unopened  and  opened.  This  waste  is  produced  in  the  native  reeling 
mills  of  China.  The  reeling  is  clone  by  steam  power,  and  the  cocoons  are 
softened  in  water,  and  treated  by  steam;  hence  the  designation  "  steam 
waste."  The  wet  waste  made  in  reeling  is  thrown  on  to  the  floor,  and  the 
gum  hardens  again  and  forms  the  silk  into  hard  knubs  or  balls.  These 
are  collected  and  put  into  bales  for  shipment  as  unopened  steam  waste. 

Opened  steam  waste  is  waste  that  has  been  pulled  into  a  loose  state  by 
the  natives,  who  use  their  fingers  and  teeth  for  the  purpose. 

China  curlies  is  another  Shanghai  waste  very  nearly  allied  to  steam 
w\aste.  Each  exporter  has  his  own  mark  or  chop,  such  as  "  yellow  pony," 
"  double  fighting  cock,"  "  golden  lion,"  etc.  It  is  a  good  waste,  rather 
longer  than  steam  waste,  and  a  little  brighter  and  stronger. 

Kikai  kihhizzo,  or  Japan  curlies,  is  another  waste  of  great  merit.  It 
is  shipped  from  Yokohama.  It  is  a  good  color,  yields  well,  and  is  generally 
of  better  quality  than  either  steam  waste  or  China  curlies.  It  is  not  a 
lustrous  waste,  but  it  is  lofty  and  gives  body  to  the  yarn. 

Iwashiro  noshi  Its  another  Japan  waste  of  superior  quality,  but  it  can  be 
obtained  only  in  small  quantity. 

Noshito  joshim  is  the  lowest  quality  of  Japan  waste  that  can  be  used 
by  spinners,  but  it  is  scarcely  worth  attention. 


SILK   NOIL  AND   SHODDY  255 

There  are  several  wastes  of  good  quality  produced  in  Persia,  Syria,  and 
Turkey,  but  they  can  be  had  only  in  comparatively  small  quantity,  and 
are  used  only  by  a  few  spinners  for  particular  purposes. 

Tussah  waste  is  a  product  of  China,  and  is  of  a  golden-brown  color 
and  of  coarse  fiber.  It  is  long,  strong,  and  lustrous,  and  makes  a  splendid 
yarn.  Owing  to  its  color  its  uses  are  somewhat  restricted.  The  yarn 
made  from  this  waste  is  used  largely  for  seal  plushes,  for  which  it  is  well 
suited.  The  strength  of  the  fiber  gives  a  spring  in  pile  goods  that  cannot 
be  obtained  from  the  finer  white  silks. 

Before  preparing  the  waste  for  the  subsequent  processes,  careful 
discrimination  is  necessary  in  determining  the  class  of  waste  best  suited 
for  the  branch  of  trade  to  be  catered  to.  For  example,  the  best  yarn  for 
the  sewing  silk  trade  cannot  be  obtained  from  steam  waste  alone.  Sewing 
silk  needs  to  be  hard,  level,  bright,  and  strong;  consequent^,  the  best 
results  will  be  obtained  from  wastes  possessing,  in  a  most  marked  degree, 
these  qualifications.  For  damask  yarns  steam  waste  and  China  curlies 
make  an  admirable  combination.  For  sewing  silk,  China,  Italian,  Pied- 
mont, and  French  waste,  and  long  knub,  are  very  suitable,  either  or  all  of 
them ;  but  care  must  be  taken  to  get  out  the  cotton.  For  hosiery  yarns  of 
the  best  grades  the  same  wastes  as  for  sewing  silks  are  suitable,  as,  although 
the  yarns  are  quite  different  in  point  of  twist  and  make-up,  they  require 
to  be  bright  and  smooth  and  free  from  neps  or  slubs.  As  a  second  grade, 
good  steam  waste  and  medium-quality  gum  w^aste  will  be  useful.  For 
lace  yarns,  best  quality  good  gum  wastes  should  be  used,  and  for  the 
lower-class  trade  steam  waste  and  curlies,  with  medium  gum  wastes, 
are  the  correct  thing.  For  the  ordinar}-  embroidery  and  tassel  trade  a 
fairly  low  class  of  either  gum  or  knub  waste,  or  a  combination  of  both, 
will  do;  but  care  must  be  taken  practically  to  free  the  waste  of  matter 
that  will  not  take  a  silk  dye.  The  high  class  embroidery  and  filoselle 
trade  need  the  best  gum  waste  and  knub  waste  obtainable,  and  these 
must  be  free  from  cotton. 

For  plushes,  punjum  waste  is  absolutely  unapproachable,  owing  to  its 
strength  and  luster  and  the  rigidity  of  the  cut  fiber.  Another  quality  for 
plushes  can  be  made  with  good  effect  from  a  mixture  of  medium  gum 
waste  and  knub  waste.  For  dark  shades  of  plush,  Tussah  waste  is  the 
ideal  fiber. 

Great  care  should  be  exercised  in  selecting  wastes  for  making  a  blend, 
and  as  nearly  as  possible  they  should  be  of  the  same  class.  For  instance, 
steam  waste  and  China  waste  should  never  be  mixed  and  dressed  together. 
They  require  different  treatment  in  the  dressing  owing  to  the  difference 
in  the  length  and  strength  of  the  fiber, 

7.  Silk  Noil  and  Shoddy. — Silk  noils  consist  of  the  short  fibers  resulting 
from  the  combing  of  spun  silk.     These  noils  are  themselves  combed  and 


256 


SILK:    ITS  ORIGIN   AND   CULTIVATION 


spun  into  coarse  yarns  on  special  machines,  and  the  yarn  so  obtained  is 
principally  used  in  the  manufacture  of  powder  bags  for  big  guns.  Silk 
noils  are  also  utilised  by  mixing  with  wool  for  the  preparation  of  fancy 
yarns  for  dress  goods. 

Silk  shoddy  resembles  wool  shoddy  in  origin,  consisting  of  recovered 
fibers  from  manufactured  silk  goods.  It  nearly  always  contains  isolated 
fibers  of  both  wool  and  cotton,  and  frequently  mixtures  of  different  kinds 
of  silk.  There  may  also  occur  boiled-off,  soupled,  and  raw  silk,  and 
mixtures  of  organzine  and  spun  silk.  Different  colors  are  also  usually 
present.  The  fibers,  as  a  rule,  are  quite  short,  being  about  a  centimeter 
in  length.  Due  to  these  components,  silk  shoddy  is  comparatively  easy 
to  recognise  under  the  microscope. 


A 


B  C 

Fig.  136. — Diseased  Silkworms.     A,  Worm  afflicted  with  flacherie;  B,  worm  emaciated 

by  gattine;   C,  calcinated  worm.     (After  Silkworm  Culture.) 


8.  Diseases  of  the  Silkworm. — The  silkworm  is  particularly  liable  to 
contract  various  diseases,  which  become  more  or  less  epidemic  in  character. 
In  the  early  history  of  sericulture  in  Europe  the  industry  was  frequently 
threatened  with  almost  total  destruction  by  the  widespread  ravages  of 
certain  diseases  of  the  silkworm.  The  French  chemist  Pasteur  devoted 
much  attention  to  this  subject  and  succeeded  in  devising  means  of  avoiding 
or  preventing  almost  all  such  diseases.  The  principal  diseases  of  the 
silkworm  are  the  following: 

(a)  Pcbrine. — Worms  afflicted  with  this  disease  develop  slowly,  irregularly,  and 
very  miequally.  Black  spots  are  the  most  marked  outward  characteristics:  the  internal 
signs  are  oval  corpuscles  visible  only  under  the  microscope.  There  appears  to  be  no 
remedy  for  this  disease,  but  Pasteur  found  it  could  be  prevented  by  a  microscopical 
selection  of  the  eggs,  and  at  the  present  day  it  causes  but  little  trouble  among  silk- 
growers.  Between  18.33  and  1865  the  annual  crop  of  cocoons  in  France  was  reduced 
by  pebrine  from  57,200.000  lbs.  to  8,800,000  lbs.     It  was  first  noticed  in  epidemic 


WILD  SILKS  257 

form  in  France  in  1845,  but  since  then  has  spread  throughout  Asia  Minor  and  the 
Orient. 

{b)  Flacherie  (or  flaccidity)  is  at  present  the  most  dreaded  disease  among  European 
silkworms.  It  usually  affects  the  worm  after  the  fourth  moult,  or  even  while  spinning. 
Without  apparent  cause  the  worms  begin  to  languish  and  shortly  die.  After  death 
they  turn  black  in  color  and  emit  a  disagreeable  odor.  Flacherie  is  apparently  a  form 
of  indigestion,  and  may  be  induced  by  micro-organisms  in  the  intestinal  canal  of  the 
worm.  Contagion  is  usually  prevented  by  dipping  the  eggs  in  a  solution  of  copper 
sulfate,  and  as  the  micro-organisms  causing  flacherie  persist  ahve  from  year  to  year, 
very  careful  fumigation  must  be  instituted  whenever  this  disease  develops. 

(c)  Gatline  shows  itself  externally  by  mdifference  of  the  worm  to  food,  torpor, 
and  generally  emaciation.  It  usually  affects  the  worm  in  the  early  ages,  though  it 
is  sometimes  associated  with  flacherie.  The  best  preventive  against  both  flacherie 
and  gattme  is  a  careful  selection  of  healthy  eggs. 

{d)  Calcino  (or  muscardine)  at  first  does  not  exhibit  any  external  characteristics, 
but  the  vitality  of  the  worm  is  slowly  impaired  and  it  feeds  and  moves  but  slowly. 
The  body  becomes  reddish  in  color,  and  gradually  contracts  and  loses  its  elasticity, 
and  the  worm  usually  dies  20-30  hours  after  the  first  symptoms  of  the  disease.  The 
dead  body  dries  up  and  becomes  covered  with  a  white  chalk-like  efflorescence.  The 
disease  is  caused  by  a  minute  fungus,  the  spores  of  which  take  root  in  the  body  of  the 
worm,  and  finally  fill  the  entire  body.  There  are  two  varieties  of  this  fungus:  Botrytis 
bassiana  and  B.  tevella.  The  white  chalk-like  appearance  of  the  dead  worm  is  caused 
by  the  branches  of  the  fungus  fructifying  on  the  surface,  and  the  fruit  bursting 
envelops  the  worm  with  innumerable  spores  resembling  a  white  powder.  Calcino 
is  the  most  contagious  of  the  silkworm  diseases,  and  its  appearance  should  be  promptly 
checked  by  careful  fumigation  with  burning  sulfur. 

(e)  Grasserie  shows  itself  by  the  worms  becoming  restless,  bloated,  and  yellow  in 
color,  and  when  punctured  they  exude  a  fetid  matter  filled  with  minute  granular 
crystals.  The  disease  is  not  caused  by  microbes,  hence  is  neither  contagious  nor 
hereditary.  Its  chief  cause  is  mismanagement  of  the  worms  at  moulting  periods  and 
uneven  feeding. ' 

9.  Wild  Silks. — Besides  the  Bomhyx  mori,  or  mulberry  silkworm,  there 
are  other  associated  varieties  of  caterpillars,  which  also  produce  silk  in 
sufficient  quantity  to  be  of  considerable  commercial  importance.  Due 
to  the  fact  that  such  silkworms  are  not  capable  of  being  domesticated  and 
artificially  cultivated  like  the  mulberry  worms,  the  silk  obtained  from 
them  is  called  wild  silk.  Of  this  latter  there  are  several  commercial  varie- 
ties, of  which  the  most  important  are  here  given. 

Anthercea  yama-mai,  a  native  of  Japan,  is  a  green-colored  caterpillar  which  feeds 
on  oak  leaves.  Its  cocoon  is  large  and  of  a  bright  greenish  color.  The  silk  bears  a 
close  resemblance  to  that  of  the  Boinbyx  mori,  but  is  not  as  readily  dyed  and  bleached 
as  the  latter. 

1  Grasserie  is  frequently  attributed  to  infection  by  a  microbe  as  yet  unknown. 
Mr.  Lambert,  the  Director  of  the  seri cultural  station  at  Montpelier,  has  shown  that 
the  disease  may  be  produced  by  feeding  the  worms  on  the  leaves  of  the  water-caltrop, 
which  they  will  eat  as  readily  as  mulberry  leaves.  As  a  matter  of  fact,  unsuitable 
feeding  seems  to  produce  the  disease,  which  Mr.  Lambert  beUeves  to  be  allied  in  some 
obscure  fashion  to  flacherie. 


258 


SILK:    ITS  ORIGIN   AND  CULTIVATION 


YiQ_    137. — Nest   of   Anaphe   Infracta,  Showing 
Moths,  Single  Cocoons  and  Chrysalis. 


follows: 

(1)  Those  with  closed  cocoons 
containing  fairly  uniform  silk 
threads  which  can  be  reeled  without 
much  difficulty:  (a)  Wild  mulberry 
silkworms;  (b)  Anther ceayama-mai; 
(c)Tussah family;  (d)  Moon^a fam- 
ily; (e)  Actias  family. 

(3)  Those  with  open  cocoons  con- 
taining silk  threads  which  cannot 
be  reeled:  (a)  Attacus  family;  (6) 
various  other  species. 

(3)  Various  species  of  Saturnida-, 
as  yet  of  no  technical  value. 

Another  variety  of  silk- 
worm which  is  to  be  found 
both  in  Asia  and  America  is 
the  Attacus  ricini.  It  gives  a 
very  white  and  good  quality 
silk,  the  production  and  value 
of  which  is  increasing  every 


Anthercea  pernyi  is  a  native  of 
China;  besides  growing  wild,  it  has 
been  domesticated  to  some  extent. 
This  worm  also  feeds  on  oak-leaves, 
but  is  of  a  yeUow  color.  Its  cocoon 
is  quite  large,  averaging  over  4  cm. 
in  length,  and  is  of  a  yellowish  to  a 
brown  color. 

Aidhcra'a  aasama  is  a  native  of 
India;  it  gives  a  large  cocoon  over 
45  mm.  in  length. 

Anthcrcrn  mylitta  is  another  In- 
dian variety,  and  furnishes  the  so- 
called  iussah  silk,  though  this  term 
has  also  been  applied  in  a  general 
manner  to  all  varieties  of  wild  silk. 
The  worms  feed  on  the  leaves  of 
the  castor-oil  plant,  and  give  very 
large  cocoons,  reaching  50  mm.  in 
length  and  30  mm.  in  diameter. 
The  fiber  is  much  longer  than  from 
the  cocoon  of  the  5.  won,  and  varies 
from  600  to  2000  yards  in  length. 
The  color  of  tussah  silk  varies  from 
a  gray  to  a  deep  brown. 

Silbermann     classifies    the 
varieties  of  wild  silkworms  as 


Fig.  138.— Nest  of  Anaphe  Silk  Cocoons. 
A,  Single  cocoons;    B,  hard   papery  layer; 
coarse  outer  layers. 


C, 


TUSSAH  SILK  259 

year.  It  is  known  as  Eria  silk.  The  structure  of  the  fiber  much  resem- 
bles that  of  tussah  silk.  A  species  of  this  class,  known  as  Attacus  atlas, 
is  perhaps  the  largest  moth  known;  it  spins  open  cocoons  and  gives  the 
so-called  Fagara,  or  Ailanthus,  silk. 

There  is  a  silkworm  found  in  Uganda  and  other  parts  of  Africa  belonging 
to  the  Anaphe  species.  It  feeds  principally  on  the  leaves  of  a  species  of 
fig  tree.  The  caterpillars  construct  large  nests  inside  of  which  they  form 
their  cocoons  in  considerable  numbers.  The  entire  nest  together  with 
the  cocoons  is  composed  of  silk,  and  the  whole  of  the  product  is  capable  of 
being  used  for  waste  silk.^  In  southern  Nigeria  this  anaphe  silk  is 
used  by  the  natives  in  conjunction  with  cotton  for  making  the  so-called 
"  soyan  "  cloths. 

10.  Tussah  Silk. — According  to  J.  K.  Davis  (Consular  Reports)  the 
silkworm  producing  tussah  silk  is  known  to  the  Chinese  as  the  shan  tsan 
or  mountain  silkworm,  and  scientifically  has  been  variously  classified  by 
different  authorities.  Among  the  classifications  given  are  Antherea  pernyi, 
Bombyx  pernyi,  and  Bombyx  fertoni.  Both  in  size  and  general  appearance 
it  is  quite  different  from  the  silkworm  which  produces  the  better  known 
white  silk.  On  maturity  it  varies  in  length  from  3  to  5  ins.,  and  is  of  a 
soft  green  color,  with  tufts  of  reddish  brown  hairs  at  different  parts  of  its 
body. 

While  the  white  silkworm  must  have  the  leaves  of  cultivated  mulberry 
trees  for  its  food,  its  less  particular  and  more  hardy  northern  cousin  sub- 
sists on  the  leaves  of  several  species  of  dwarf  mountain  oak  which  are 
native  to  eastern  Manchuria,  and  grow  uncultivated  in  great  abundance 
on  the  sides  of  the  otherwise  rather  unproductive  hills  that  traverse 
this  entire  district.  These  trees  serve  the  purposes  of  sericulture  best 
when  at  a  height  of  from  5  to  6  ft.,  and  are  accordingly  kept  from  growing 
too  tall  by  prunings  made  at  intervals  of  several  3^ears.  Where  the  natural 
groves  are  insufficient  recourse  is  had  to  artificial  planting  from  seed. 
This,  however,  is  a  slow  process,  since  from  four  to  seven  years'  growth 
is  required  to  produce  a  tree  useful  for  feeding,  and  the  trees  are  not  at 
their  best  until  they  are  from  twelve  to  sixteen  years  old. 

Two  crops  of  cocoons  are  produced  annually,  one  in  the  spring  and 
one  in  the  autumn.     The  spring  crop  is  put  on  the  market  early  in  July; 

1  The  Imperial  Institute  has  made  an  extensive  investigation  on  the  utilisation  of 
anaphe  wild  silk.  There  is  an  outer  layer  or  nest  which  contains  the  cocoons  located 
within,  and  as  this  outer  layer  is  more  difficult  to  degum  than  the  cocoons  it  is  advisable 
to  separate  it  from  them  and  work  it  up  for  the  fiber  by  itself.  When  the  nests  of 
the  anaphe  silk  are  handled  in  the  dry  state  they  cause  an  intense  irritation  of  the 
skin  and  mucous  membrane,  presumably  due  to  the  enclosed  hairs  of  the  caterpillars; 
therefore,  before  the  nests  are  separated  from  the  cocoons  they  must  be  soaked  in 
water,  or  better  yet,  it  is  advised  to  boil  the  envelopes  for  two  hours  in  a  1  percent 
solution  of  sodium  carbonate. 


260  SILK:    ITS  ORIGIN   AND  CULTIVATION 

it  is  the  smaller  of  the  two,  and  is  used  principally  to  produce  eggs  for  the 
autumn  crop,  which  is  usually  marketed  after  the  middle  of  October. 
The  usual  method  of  killing  the  chrysalides  is  by  storing  cocoons  in  large 
warehouses  capable  of  being  heated,  and  in  the  midst  of  the  extreme 
cold  season  (in  Manchuria)  raising  the  temperature  to  that  of  a  spring 
day  for  a  period  of  several  days,  after  which  it  is  lowered  to  the  outside 
atmospheric  temperature  again.  When  this  process  has  been  repeated 
several  times  the  chrysalides  are  killed  and  the  cocoons  may  then  be 
carried  over  to  the  summer  with  no  danger  of  being  pierced. 

Cocoons  are  prepared  for  reeling  by  a  process  of  steaming,  which  serves 
to  dissolve  the  secretion  with  which  the  component  fibers  have  been 
fastened  together.  This  process  also  kills  the  chrysalides  in  the  case  of 
the  cocoons  which  have  not  been  treated  by  the  process  just  described. 
Steaming  is  done  in  large  iron  caldrons  sunk  into  brick  stoves,  which  are 
usually  located  in  a  room  immediately  adjoining  that  in  which  the  reeling 
is  to  take  place.  The  caldron  is  first  filled  with  a  solution  made  by  dis- 
solving in  water  approximately  6  to  8  ounces  of  soda  for  each  thousand 
cocoons  to  be  steamed,  and  after  this  mixtiu'e  has  been  heated  to  the 
boiling  point  the  cocoons  are  thrown  in  and  rapidly  stirred  for  several 
minutes.  They  are  then  dipped  out  and  put  into  a  round  container, 
not  unlike  a  deep  sieve  in  appearance  but  with  parallel  strips  of  bamboo 
for  a  bottom,  which  is  placed  immediately  over  the  caldron  so  that  the 
bamboo  slats  are  only  an  inch  or  more  above  the  surface  of  the  boiling 
solution,  and  in  this  position  are  steamed  for  several  hours. 

When  the  process  of  steaming  has  been  completed  the  inextricable 
mass  of  tangled  fibers  which  form  the  outer  covering  of  the  cocoons,  and 
which  is  known  as  ta-wan-shu,  or  "  big  waste,"  is  removed;  the  innermost 
fibers  which  actually  enwrap  the  chrysalides  are  hopelessly  tangled,  and 
are  known  as  the  erh-wan-shu,  or  "  second  waste."  From  its  nature  waste 
cannot  be  reeled  as  is  the  thread,  but  must  be  chopped  up,  combed,  carded, 
and  spun.  Heretofore  waste  has  always  been  shipped  to  Europe  for 
manufacture. 

After  the  outer  waste  has  been  removed  the  cocoons  are  taken  into  the 
reeling  room  and  distributed  to  the  reel  operators,  who  are  usually  arranged 
on  high  platforms  running  the  length  of  a  long,  narrow  room,  one  operator 
to  a  reel.  Each  operator  then  gathers  the  ends  of  the  fibers  of  from  6  to 
8  cocoons,  twists  them  into  a  thread  which  he  fastens  to  his  reel,  and  by 
means  of  a  treadle  starts  the  reel  revolving.  As  the  thread  passes  through 
several  rings  before  reaching  the  reel  it  is  twisted,  and  is  wound  on  to  the 
reel  in  the  form  of  the  finished  thread.  The  reels  are  of  two  sizes,  one 
with  a  diameter  of  1^  ft.  and  the  other  2|,  and  in  Antung  are  all  operated 
by  foot  power. 

The  average  capacity  of  an  operator  is  from  700  to  900  cocoons  a  day 


TREATMENT  OF  WILD  SILK  COCOONS  261 

while  the  experts  attain  occasionally  to  1200.  The  skeins,  which  are 
usually  some  4  feet  in  circumference,  are  folded  once  and  twisted  spirally. 
The  thread,  when  it  has  been  manufactured  into  skeins  in  this  manner, 
is  known  as  "  tussah." 

The  silk-producing  qualities  of  the  spring  and  autumn  cocoons  are 
different.  One  thousand  spring  cocoons  will  furnish  from  5|  to  8  ozs. 
avoirdupois  of  tussah,  w^hereas  the  autumn  cocoons  yield  from  8  to  12*ozs. 
The  silk  produced  from  the  spring  cocoons  is  of  a  softer  and  more  pleasing 
texture  than  that  from  the  later  ones. 

Tussah  is  classified  by  the  Chinese  trade  into  five  grades,  known  as 
"  extra,"  "  No.  1,"  "  No.  2,"  "  No.  3,"  and  "  No.  4,"  according  to  quality. 
It  is  also  divided  into  two  general  classes,  "  not  filature  "  and  '*  filature." 
The  term  "  not  filature  "  is  applied  to  that  reeled  on  a  small  scale  in  many 
different  localities,  and  which  as  a  result  lacks  uniformity,  while  "  filature  " 
is  used  to  describe  the  product  of  the  larger  factories,  which  maintain 
standards  of  approximate  uniformity. 

Waste  is  commercially  divided  into  two  classes — No.  1  and  No.  2 — 
which  correspond  generally  to  the  "  big  waste  "  and  "  second  waste  " 
already  described.  It  is  usually  put  up  into  bales  of  from  2  to  3  piculs 
(266f  to  400  lbs.). 

11.  Treatment  of  Wild  Silk  Cocoons. — Wild  silk  is  much  more  dif- 
ficult to  unwind  from  the  cocoons  than  that  of  the  mulberry  silkworm,  and 
is  also  much  darker  in  color.  As  the  individual  filaments  are  much  coarser 
than  those  of  mulberry  silk  the  former,  as  a  rule,  have  greater  strength, 
but  on  reduction  to  a  basis  of  equal  diameters,  the  filaments  of  mulberry 
silk  are  somewhat  stronger,  and  are  much  less  difficult  to  dye  and  bleach. 

The  cocoons  of  tussah  silk  are  usually  boiled  in  an  alkaHne  solution 
before  reeling.  The  natives  add  the  ashes  of  plantain  leaves  to  water  and 
boil  the  cocoons  in  this  Hquor  for  two  to  three  hours,  and  then  leave  them 
to  ferment  for  some  hours  before  reeling.  In  some  factories  in  Bengal, 
the  cocoons  with  their  stems  cut  off  are  tied  up  loosely  in  a  cloth,  which  is 
weighted  down  with  stones  and  boiled  for  half  an  hour  in  a  liquor  containing 
3  parts  of  potassium  carbonate  dissolved  in  80  parts  of  water,  oil  and 
sugar  being  sometimes  added.  The  cocoons  are  afterward  boiled  for  a 
few  minutes  in  water  containing  a  Httle  glycerol.  The  silk  is  then  reeled 
in  the  same  way  as  mulberry  silk.  The  glycerol  keeps  the  cocoons  moist 
while  reeling,  and  it  is  not  necessary  to  keep  them  in  basins  of  water  during 
this  operation.  Another  method  is  to  prepare  a  fine  powder  or  paste 
from  the  chrysalides  of  the  silk  insects;  and  about  1  part  by  weight  of  this 
is  mixed  with  2  parts  by  weight  of  dry  cocoons,  and  the  mixture  is  tied  up 
in  a  cloth,  immersed  in  water  and  boiled  for  an  hour.  The  mixture  is 
next  left  to  ferment  for  twelve  hours,  after  which  the  reeling  begins, 
the  cocoons  being  allowed  to  rotate  in  basins  of  hot  water.    The  reeled 


262  SILK:    ITS  ORIGIN  AND  CULTIVATION 

silk,  obtained  by  whatever  process,  must  next  be  immersed  in  a  warm 
acid  solution,  then  washed  in  a  bath  of  boiling  soap  or  washing  soda  solution, 
and  finally  rinsed  in  boiling  water,  wrung  out,  dried,  and  baled.  The 
object  of  the  acid  bath  is  to  neutralise  the  lime  and  alkali  which  would 
lessen  the  brilliancy  and  elasticity  of  the  fiber.  The  acid  solution  is 
prepared  from  tamarinds,  using  1  part  by  weight  of  tamarinds  to  every  4 
parts  of  silk.  The  tamarinds  are  washed  and  mixed  with  water,  and  the 
liquor  is  strained  through  a  cloth.  One  man  can  reel  about  260  tussah 
cocoons  in  a  day,  obtaining  about  ^  lb.  of  silk.  One  difficulty  in  reeling 
tussah  silk  is  to  make  the  separate  strands  cohere  in  the  reeled  thread; 
in  the  case  of  mulberry  silk  the  glue  is  only  softened  in  the  reeling  basin 
and  glues  the  strands  together  by  hardening  again. 

Tussah  (or  tussur)  silk,  as  well  as  other  wild  silks,  is  chiefly  employed 
for  making  pile-fabrics,  such  as  velvet,  plush,  and  imitation  sealskin. 

12.  Spider  Silk. — Attention  has  recently  been  drawn  to  the  possibility 
of  obtaining  silk  from  a  species  of  spider  chiefly  found  in  Madagascar. 
The  spider  is  known  as  Nephila  Madagascariensis.  The  egg-receptacle 
is  a  silky  cocoon  about  1  in.  in  diameter  and  of  a  yellow  color,  but  turning 
white  after  several  months'  exposure  to  the  air.  The  female  spider  alone 
produces  the  silk  and  is  about  2\  ins.  long.  The  silk  is  reeled  off  from 
the  spider  five  or  six  times  in  the  course  of  a  month,  after  which  it  dies, 
having  yielded  about  4000  yds.  The  reeling  is  done  by  native  girls; 
about  one  dozen  spiders  are  locked  in  a  frame  in  such  a  manner  that  on 
one  side  protrudes  the  abdomen,  while  on  the  other  side  the  head,  thorax, 
and  legs  are  free.  The  ends  of  their  webs  are  drawn  out,  collected  into 
one  thread,  which  is  passed  over  a  metal  hook,  and  the  reel  is  set  in  motion 
by  a  pedal.  The  extraction  of  the  web  does  not  apparently  inconvenience 
the  spider.  The  cost  of  the  material  is  high,  as  55,000  yds.  of  19  strands 
thickness  weighs  only  386  grains,  and  1  lb.  of  the  silk  is  worth  $40.  At 
the  Paris  Exposition  of  1900,  a  fabric  was  shown,  18  yds.  long  by  18  ins. 
wide,  containing  100,000  yds  of  spun  thread  of  24  strands,  the  product 
of  25,000  spiders.  It  was  golden  yellow  in  color.  Spinning  spiders  are 
also  known  in  Paraguay,  Venezuela,  and  other  countries. 

Spider  silk  under  the  microscope  appears  solid,  almost  completely 
transparent,  of  approximately  circular  cross-section  and  without  any 
internal  structure.  The  extraordinary  fineness  of  the  white  threads  is 
noticeable,  the  average  diameter  being  only  6.9  microns;  consequently 
they  are  the  finest  animal  silk  product,  being  finer  even  than  the  most 
delicate  filaments  of  artificial  silk.  Spider  silk  is  not  surrounded  by  an 
enveloping  substance  like  the  sericine  of  ordinary  silk.  The  density  is 
about  the  same  as  that  of  ordinary  silk — namely,  1.34.  When  immersed 
in  water  spider  silk  swells  considerably  and  contracts  in  length.  In  its 
microchemical  tests  it  is  similar  to  true  silk. 


SILK  STATISTICS 


263 


The  threads  spun  by  the  Nephila  Madagascariensis  closely  resembles 
ordinary  silk  in  external  appearance.  Each  spider  produces  about  150-600 
meters  of  fiber.  The  silk  has  an  orange-j^ellow  color,  which  becomes 
intensified  by  alkalies  and  is  destroyed  by  acids.  It  differs  from  ordinary 
silk  principally  in  its  small  amount  of  silk-glue  (or  water-soluble  sub- 
stances). According  to  Fischer^  spider  silk  gave  the  following  products 
when  hydrolysed  with  acid: 

Percent. 

Glycocoll 25. 13 

rf-alanine 23.40 

Meucine 1 .  76 

Proline 3 .  68 

/-tyrosine 8 .  20 

d-glutaminic  acid 11 .  70 

Diamino  acids 5 .  24 

Ammonia 1 .  16 

Fatty  acids 0. 59 

Glutaminic  acid,  which  is  present  in  rather  a  large  amount  in  spider 
silk,  has  not  been  found  in  ordinary  silk.  Spider  silk,  on  ignition,  gave 
0.59  percent  of  ash. 

13.  Silk  Statistics. — With  the  possible  exception  of  China,  for  which 
no  complete  statistics  are  available,  the  United  States  is  now  the  largest 
silk  manufacturing  country  in  the  world. 

The  following  tables  indicating  the  extent  of  the  silk  manufacturing 
industry  in  the  United  States  for  the  year  1919  have  been  taken  from  the 
U.  S.  Census  Reports: 

PRINCIPAL  MATERIALS  USED  IN  SILK  INDUSTRY 


Materials. 


Raw  silk 

Organzine,  tram  and  hard  crepe  twist. . 

Spun  silk 

Prisons,    pierced    cocoons,    noils    and 

other  waste 

Artificial  silk 

Cotton  yarns  (not  mercerised) 

Mercerised  cotton  yarns 

Woolen  and  worsted  yarns 

Mohair  and  other  varns 


Quantity,  Pounds. 


1919. 


25,890,728 
6,125,490 
4,767,679 

11,461,588 
3,039,257 

15,131,047 

2,826,965 

638,334 

1,042,790 


1914. 


23,374,700 
3,855,899 
3,209,309 

4,328,-536 
1,902,974 
16,869,511 
1,464,299 
1,987,918 
2,936,727 


Cost,  Dollars. 


1919. 


206,222,609 
62,487,939 

25,874,715 

16,136,213 

15,885,564 

14,151,863 

4,266,593 

2,1.57,743 

2,214,584 


1914. 


86,416,857 

16,703,096 

8,094,427 

3,066,297 
3,440,154 
6,163,240 
1,078,337 
2,087,804 
2,043,306 


1  Zeit.  physiol.  Chem.,  1907,  p.  126. 


264 


SILK:     ITS  ORIGIN   AND   CULTIVATION 


The  following  table  gives  the  value  of  the  various  manufactured 
products  pi  the  domestic  silk  industr}^ : 

PRODUCTS  OF  THE  SILK  INDUSTRY 


Total  value 

Broad  Silks:  Yards 

Value 

Velvets :  Yards 

Value 

Plushes :  Yards 

Value 

Upholstery  and  Tapestries :  Yards 

Value 

Ribbons,  value 

AUSilk,  value 

Silk  and  Other  Materials,  value 

Laces,  Nets,  Veils,  Veiling,  etc.,  value 

Embroideries,  value 

Fringes  and  Gimps,  value 

Braids  and  Binding,  value 

Tailor's  Trimmings,  value 

Military  Trimmings,  value 

Machine  Twist :  Pounds 

Value 

Sewing  and  Embroidery  Silk :  Pounds 

Value 

Fringe  and  Floss  Silks:  Pounds 

Value 

Organzine,  for  sale:  Pounds 

Value 

Tram,  for  sale :  Pounds 

Value 

Hard  Crepe  Twist,  for  sale:  Pounds 

Value 

Spun  Silk,  for  sale:  Pounds 

Value 

Spun  Silk,  for  sale.  Singles:  Pounds 

Value 

Spim  Silk,  for  sale,  two  or  more  ply:  Pounds 

Value. . 

Artificial  Silk:  Pounds 

Value 

All  other  Products,  value 

Received  for  contract  work 


1919. 


1914. 


$688,502,534 

$254,011,257 

310,132,060 

216,033,696 

$391,735,902 

$137,719,564 

16,150,689 

16,318,135 

$20,950,239 

$8,570,022 

5,860,427 

9,114,992 

$21,601,280 

$10,135,842 

516,281 

477,699 

$2,156,617 

$840,126 

$66,186,609 

$38,201,293 

52,047,330 

14,139,279 

. 

$5,825,359 

$1,328,933 

127,522 

$33,500 

3,026,560 

1,025,188 

13,218,284 

3,073,648 

634,058 

210,741 

682,909 

431,422 

773,843 

659,540 

$10,644,095 

$4,036,807 

515,222 

902,499 

$7,089,813 

$5,644,806 

38,107 

$500,571 

886,014 

1,492,999 

$9,122,457 

$6,325,291 

3,611,901 

2,577,402 

$31,494,535 

$9,698,637 

1,070,845 

$12,011,137 

3,956,687 

1,607,416 

$23,807,338 

$4,577,058 

1,764,028 

$11,733,463 

2,192,609 

$12,073,875 

829,083 

$5,423,242 

$23,928,982 

$13,757,772 

38,335,025 

8,400,607 

SILK  STATISTICS  265 

The  total  estimated  production  of  raw  silk  in  the  world  for  the  year 
1914  was  as  follows:^ 

Italy. 7,357,000  lbs. 

France 799,000  " 

Austria 655,000  ' ' 

Spain 164,000  " 

Europe 8,975,000  lbs. 

Levant 5,115,000  " 

China,  Shanghai 8,651,000  lbs. 

China,  Canton 5,876,000  ' ' 

Japan 25,132,000  " 

India 343,000  " 

Asia  (exported) 40,002,000  lbs. 

Total 54,092,000  " 

Raw  Tussah 3,307,000  ' ' 

1  The  filatures  (silk  reeling  establishments)  in  Europe  and  the  Levant  for  the  year 
1920  are  given  as  follows: 

Basins.  Filatures. 

Italy 58,620  1,039 

France 16,000  161 

Brussa 50 

Syria 30 

Turkey  (all  provinces) 114 

Greece 22 

In  Italy  the  reeling  of  raw  silk  from  the  cocoon  is  done  almost  exclusively  by 
girls,  who  receive  about  28  cents  per  day  of  eleven  hours;  in  Turkey  the  pay  is  about 
30  piastres.  In  China  and  Japan  the  pay  is  even  lower  than  this.  As  silk  reeling 
has  to  be  done  by  hand  labor,  and,  owing  to  the  fineness  of  the  thread  and  the  close 
inspection  necessary,  only  a  relatively  small  production  of  reeled  silk  can  be  obtained 
from  each  operative,  it  will  readily  be  appreciated  that  this  operation  could  not  be 
conducted  in  either  America  or  England  on  account  of  the  much  higher  cost  of  any 
available  labor.  Even  in  Italy  and  France,  since  the  advent  of  the  war,  labor  costs 
of  even  girl  sUk  reelers  have  much  advanced,  and  it  is  becoming  increasingly  difficult 
to  obtain  a  good  supply  of  satisfactory  labor.  SUk  reeling  requires  skill  and  a  con- 
siderable period  of  apprenticeship,  and  a  good  silk  reeler  is  to  be  considered  as  a 
skilled  laborer.  There  is  no  doubt  that  the  cost  of  silk  reeling  will  be  continually 
advancing  even  in  Japan  and  China,  though  it  will  perhaps  take  many  years  before 
the  labor  in  these  countries  will  come  up  to  anything  approaching  par  with  European 
countries.  It  seems  rather  certain  therefore  that  sericulture  in  Italy  and  France,  and 
even  in  the  Levant,  will  show  a  tendency  to  decrease  and  that  of  China  and  Japan 
to  increase  in  the  next  couple  of  decades.  As  the  cost  of  reeling  silk  from  the  cocoons 
is  one  of  the  principal  factors  in  the  cost  of  raw  silk,  it  also  seems  certain  that  the 
price  of  raw  silk  will  continually  tend  to  seek  higher  levels,  and  there  is  very  little 
likelihood  of  its  ever  going  back  to  the  old  pre-war  figure.  Another  factor  to  be  con- 
sidered is  the  increasing  production  of  artificial  silk,  which  in  many  cases  is  capable 
of  taking  the  place  of  real  silk  and  at  a  much  lower  cost.  While  the  price  of  real  silk 
has  every  force  acting  to  make  it  rise,  the  price  of  artificial  silk,  being  almost  entirely 
a  mechanical  operation,  will  tend  to  fall.     We  may  expect,  therefore,  that   artificial 


266 


SILK:    ITS  ORIGIN   AND   CULTIVATION 


The  figures  given  for  Asiatic  silk  are  the  exports,  as  the  production  of 
raw  silk  in  China  is  not  known.  The  domestic  consumption  of  Japan 
is  estimated  as  about  30  percent  of  the  production,  so  the  total  production 
for  Japan  would  be  about  34,072,800  lbs.  The  domestic  consumption 
of  China  is  estimated  as  about  55  percent  of  the  production,  so  the  total 
production  of  China  may  be  taken  as  about  41,604,000  lbs. 

The  production  and  exportation  of  raw  silk  has  become  one  of  the 
principal  industries  of  Japan.  In  that  country  three  silk  crops  are  raised 
- — in  the  spring,  summer,  and  autumn.  These  form,  respectively,  about 
50  to  55  percent,  5  to  10  percent,  and  35  to  40  percent  of  the  total  annual 
production. 

The  following  figures  for  the  world's  production  of  silk  over  a  number  of 
years  are  given  by  the  Board  of  Trade  Journal: 


WORLD'S  PRODUCTION  OF  SILK,   1876-1910 


Period. 

W.  Europe. 

S.E.  Europe, 
Levant,  etc. 

Far  East. 

Total. 

Kilos. 

Ivilos. 

Kilos. 

ffilos. 

1876-1880 

2,475,000 

637,000 

5,740,000 

8,854,000 

1881-1885 

3,630,000 

700,000 

5,108,000 

9,438,000 

1886-1890 

4,340,000 

738,000 

6,522,000 

11,600,000 

1891-1895 

5,518,000 

1,107,000 

8,670,000 

15,295,000 

1896-1900 

5,220,000 

1,552,000 

10,281,000 

17,053,000 

1901-1905 

5,312,000 

2,304,000 

11,476,000 

19,092,000 

1906-1910 

5,459,000 

2,636,000 

14,917,000 

23,012,000 

For  Persia,  Turkestan,  and  the  Far  East  the  figures  given  are  for 
exports  only,  and  do  not  include  what  may  have  been  used  in  domestic 
consumption  in  those  countries. 

During  the  World  War,  of  course,  the  production  of  silk  in  Europe 
and  the  Levant  fell  off  very  greatly,  and  owing  to  the  disturbed  condition 
of  these  countries  ever  since  the  recovery  in  this  industry  has  been  very 
slow.  There  have  been  many  efforts  on  the  part  of  the  various  govern- 
ments interested  to  re-establish  sericulture  on  even  a  greater  scale  than 
ever  before,  but  progress  so  far  has  been  rather  slow. 

The  following  tables  have  been  compiled  by  the  Silk  Association  of 
America  (1922): 


silk  will  displace  real  silk  in  many  of  its  uses,  and  the  true  fiber  of  the  silkworm  will 
be  confined  to  the  manufacture  of  those  higher  grade  and  more  costly  materials  for 
which  it  is  so  eminently  suited,  and  for  which  artificial  silk  would  be  a  poor  substitute. 


SILK  STATISTICS 


267 


RAW  SILK  PRODUCTION,  INCLUDING  TUSSAH  SILK 


Crops  in  Pounds. 


Europe 

Italy 

France 

Austria 

Spain 

Levant 

Asia:  Total  quantity  exported 

China,  Shanghai 

China,  Canton 

Japan,  Yokohama 

India 

Total,  pounds 

Tussah 

Grand  total,  poimds .  .  . 


1921-1922. 
Pounds. 


7,628,000 

7,066,000 
430,000 

132,000 

1,213,000 

48,740,000 

6,555,000 

5,578,000 

36,376,000 

231,000 

57,581,000 
1,856,000 


59,437,000 


1920-1921. 
Pounds. 


8,058,000 

7,330,000 
551,000 

177,000 

1,654,000 

35,138,500 

6,518,500 

4,210,000 

24,300,000 

110,000 

44,850,500 
1,650,000 


46,500,500 


1919-1920. 
Pounds. 


4,927,000 

4,045,000 
397,000 
331,000 
154,000 

2,293,000 

51,860,000 

10,225,000 

7,093,000 

34,222,000 

320,000 

59,080,000 
1,960,000 


61,040,000 


The  production  of  raw  silk  in  China  ^  and  India  is  unknown.  The 
Japan  crop  is  approximately  45,642,000  lbs.  The  export  figures  from 
Shanghai,  China,  exclude  tussah  silk.  The  world's  production  for  1913 
(pre-war)  was  estimated  at  60,104,000  lbs.,  so  it  may  be  seen  that  the  war 
seriously  interfered  with  the  natural  increase  in  silk  production,  as  the 
figures  for  1922  are  practically  the  same  as  for  1913,  The  quantity  of 
silk  produced  in  western  Europe  is  steadily  decreasing.  There  have  been 
recent  attempts  to  introduce  sericulture  into  the  French  African  and 
Eastern  Colonies,  but  satisfactory  climatic  conditions  have  not  been 
attained, 

1  The  silks  of  North  China  include  those  known  as  "steam  filatures,"  which  are 
reeled  by  European  methods,  and  those  known  as  "Tsatlees,"  which  are  reeled  in  a 
very  primitive  fashion  without  killing  the  chrysalides  in  the  cocoons.  The  Tsatlee 
silk  is  therefore  usually  coarse  and  irregular.  Chinese  and  Japanese  silks  are  packed 
in  picul  bales  of  133^  lbs.  Canton  silk  comes  from  the  south  gi  China  and  is  generally 
reeled  in  the  14/16  denier  size  and  is  packed  in  bales  of  80  catties  (equivalent  to  106f  lbs.) . 
Japanese  silks  are  usually  quoted  in  terms  of  yen  per  100  kin  (132.277  lbs.).  The 
momme  weight  is  0.13228  oz.  and  this  factor  is  often  employed  in  calculations  relating 
to  Japanese  silks. 


268 


SILK:    ITS  ORIGIN   AND   CULTIVATION 


1921-1922. 

SUk  Products 

Pounds. 

Value. 

Raw  Silk                

48,178,964 

9,097,339 

161,044 

$300,445,363 

Waste  Silk       .                            

6,717,210 

Cocoons                                              

120,310 

Fabrics  in  the  Piece :  France 

264,071 
51,720 
75,413 

484,456 

2,171,849 

92,284 

2,119,032 

Italy 

377,737 

Switzerland 

556,923 

China . .       

1,359,889 

Japan ....         

13,495,068 

Other  Countries 

648,032 

Total    

3,139,793 

$18,556,681 

8,366,852 

$451,160 

$4,369,784 

United  Kingdom 

577,290 

199,182 

Other  Countries 

460,078 

Total 

$5,606,334 

Velvets  Plushes  and  Other  Pile  Fabrics 

387,490 
779,008 
137,131 
470,274 
92,333 
16,192 

$2,603,813 

Spun  Silk  or  Schappe  Silk :  France 

2,178,214 

Italy .            

460,947 

Switzerland    

1,438,415 

United  Kingdom 

205,220 

Other  Countries 

26,735 

Total 

1,494,938 

$4,309,531 

Wearing  Apparel '.  France                

$3,228,854 

Switzerland              

121,415 

United  Kingdom .           

492,132 

Japan                            

1,040,222 

Other  Countries 

732,150 

Total.             

$5,614,773 

Bandings  Beltings  Bindings  etc          .       

$253,945 

All  Other  Manufactures   

2,634,096 

Total  Dutiable  Silk 

$40,030,333 

Bolting  Cloth  

307,511 

Total  Silk  Manufactures 

$40,337,844 

Artificial  Silk  Yarns      .  .    .  .        

2,912,960 

$5,091,940 

Artificial  Silk,  all  other 

2,026,082 

Total  Artificial  Silk 

$7,118,022 

SILK  STATISTICS 


269 


The  table  on  page  268  gives  the  silk  products,  other  than  raw  silk, 
imported  into  the  United  States  during  the  year  1921-22  as  reported  by 
the  Department  of  Commerce. 

IMPORTS  OF  RAW  SILK  MATERIALS  INTO  THE  UNITED  STATES 


Imports. 

Raw  Silk,  including  Tussahs  and  Doppioni,  bales . . 
Raw  Silk,  including  Tussahs  and  Doppioni,  pounds 

Raw  Silk,  invoice  value,  dollars 

Spun  Silk,  pounds 

Spun  Silk,  invoice  value,  dollars 

Waste  Silk,  pounds 

Waste  Silk,  invoice  value,  dollars 


1921-1922. 


354,363 

48,178,964 

$300,445,363 

1,494,938 

$4,309,531 

9,097,339 

$6,717,210 


The  Classification  of  the  Receipts  of  Raw  Silk  in  the  United  States 


1921-1922. 

Shipping  Bales. 

Bales. 

Pounds. 

Value. 

Europeans 

Japans 

Cantons 

Chinas 

9,103 

282,450 

40,559 

16,810 

5,441 

2,260,177 

38,590,110 

4,341,995 

2,249,477 

737,205 

$  12,538,596 

249,108,057 

23,331,168 

13,190,413 

2,277,129 

Tussahs 

Totals 

354,363 

48,178,964 

$300,445,363 

CHAPTER  X 

PHYSICAL  PROPERTIES  OF  SILK 

1.  The  Microscopy  of  the  Silk  Fiber. — Under  the  microscope  raw  silk 

exhibits  an  appearance  which  readily  distinguishes  it  from  other  textile 

fibers.     The  fiber  of  fibroine  when  purified  from  adhering  sericine  is  seen 

as  a  smooth  structureless  filament,  very  regular  in  diameter  and  very 

transparent.     Occasionally   constrictions  occur  in  the  fiber  as  well  as 

swellings  or  lumps.     The  two  brins  in  the  bave  of  raw  silk  give  beautiful 

colors  with  polarised  light  when  examined  microscopically.     The  sericine 

coating,  however,  appears  to  have  no  such  action.     The  latter,  being  hard 

and  brittle,  on  bending  develops  transverse  cracks  which  are  very  apparent 

under  the  microscope. 

The  fiber  of  Bombyx  mori  is  only  rarely  striated  longitudinally,  and 

when  such  striations  do  appear  they  always  run  parallel  to  the  axis  of  the 

fiber.     When  treated  with  dilute  chromic  acid  very  fine  striations  are 

caused  to  appear.     Wild  silks  often  show  fibers  which  are  twisted  on  their 

axes,  and  the  layer  of  gum  is  usually  more  or  less  granular.     Ayithercea 

mylitta   shows   rather    frequent   oblique 

striations,  and  does  not  exhibit  much  play 

of  color  with  polarised  light.     This  latter 

characteristic   is  also  true  of  Anthercea 

^      ,„„     ^  .         .  r,„   T.-    vama-mai.      The   other   silks  give   nice 

Fig.  139. — Cross-sections  of  hilk  Fi-   ^   ,  .^,  ,     .      ,   ,.   ,  ,        c?.„    ^, 

ber.    (X500.)    «,  From  inner  part  colors  with  polarised  light.      Silk  fibers 

of  cocoon;  6,  from  middle  layers;  c,  are  colored  a  deep  red  with  alloxanthm ; 
from  outer  part;/,  fiber  of  fibroine;  fuchsine  also  gives  a  red  color.  On 
s,  layer  of  sericine.  (Micrograph  treatment  with  sugar  and  sulfuric  acid, 
by  author.)  gjlj^  -g  g^.g^.    ^Qjored  a  rose-red  and  then 

dissolves;  hydrochloric  acid  gives  a 
violet  color  and  then  dissolves  the  fiber.  Iodine  colors  the  fibers  yellow 
to  reddish  brown. 

Carded  silk,  which  has  been  worked  up  from  imperfect  cocoons,  etc., 
can  usually  be  recognised  under  the  microscope  by  the  irregular  and  torn 
appearance  of  its  external  layer  of  gum. 

The  inner  layers  of  the  cocoon  consist  of  a  yellow  parchmentlike  skin, 
and  when  examined  under  the  microscope  exhibit  a  matrix  of  sericine, 
in  which  numerous  double  fibers  are  imbedded,  usually  very  much  flattened 

270 


THE   MICROSCOPY  OF   THE   SILK   FIBER 


271 


in  cross-section  (Fig.  139,  a) 
capable  of  being 
reeled  with  the  rest 
of  the  cocoon,  and 
are  used  for  waste 
silk.  The  cross-sec- 
tions of  the  fibers 
from  the  middle 
portion  of  the  co- 
coon, constituting 
the  reeled  silk  are 
much  more  rounded 
in  form  and  are 
surrounded  with  a 
thinner  layer  of 
sericine  (Fig.  139, 
b).  The  fibers  of 
the  outer  part  of 
the  cocoon,  also 
utilised  for  waste 
silk,  exhibit  a 
rather  irregular 
cross-section  (Fig. 
139,  c). 


These   inner  layers,  of  course,  are  not 


Fig.  140. — Appearance  of  Raw  Silk  (X 500)  under  the  Micro- 
scope, Showing  the  Double  Cocoon  Filament  and  the  Irregu- 
lar Shreds  of  Silk-glue.     (Micrograph  by  author.) 


When  raw  silk  is  examined  under  the  microscope  it  will  be  seen  that 

the  appearance  is  by  no  means  regular, 
owing  to  the  broken  and  torn  surface  of 
sericine  which  surrounds  the  fiber  (Fig. 
140).  Frequently  the  two  filaments  of 
fibroine  are  distinctly  separated  from  one 
another  for  considerable  distances,  the  in- 
tervening space  being  filled  in  with  sericine. 
Occasionally  the  layer  of  sericine  is  seen  to 
be  entirely  absent,  having  been  removed  by 
breaking  or  rubbing  off.  The  sericine 
layer  also  shows  frequent  traverse  fissures, 
which  are  merely  cracks  caused  by  the 
breaking  of  the  sericine  in  the  bending  or 
twisting  of  the  fiber.  Creases  and  folds  in 
A  View  of  narrow  side;  B,  view  ^^^  sericine,  as  well  as  irregular  lumps,  are 
of  broad  side;  C,  cross-section;      ,  c    i-  ,  a  n      r  /i 

D,  cross-section  of  double  fiber;  ^^^^  of  frequent  occurrence.  All  of  these 
cr,  cross-marks  on  fiber.  (Mi-  markings  are  in  nowise  structural,  and  only 
crograph  by  author.)  occur  in  the  sericine  layer.      At  times  the 


Fig.    141.— Wild  Silk.      (X250. 


272 


PHYSICAL   PROPERTIES  OF  SILK 


fibroine  fiber  exhibits  structural  changes  in  places,  such  as  attenuations ; 
but  these  only  occur  in  defective  and  unhealthy  silk,  and  give  rise  to 
weak  places.  These  are  caused  by  the  fibroine  not  being  secreted  by  the 
gland  with  sufficient  rapidity  when  the  fiber  is  being  spun  by  the  worm. 

The  microscopic  appearance  of  the  wild  silks  is  very  different  from 
that  of  the  Bombyx  mori.  The  fibers  are  very  broad  and  thick,  and  in 
cross-section  are  very  flat,  and  often  triangular  in  outline.  Longitudinally 
they  show  very  distinct  striations  and  peculiar  flattened  markings,  usually 
running  obliquely  across  the  fiber,  and  in  which  the  striations  become 

more  or  less  obliter- 
ated. These  cross- 
markings  are  caused 
by  the  overlapping 
of  one  fiber  on  an- 
other before  the  sub- 
stance of  the  fiber 
had  completely  hard- 
ened, in  consequence 
of  which  these  places 
are  more  or  less  flat- 
tened out  (Fig.  141). 
The  striated  appear- 
ance of  wild  silk  is 
evidence  that  struc- 
turally the  fiber  is 
composed  of  minute 
filaments ;  in  fact  the 
latter  may  readily 
be  isolated  by  mace- 
ration in  cold  chromic 
acid  (Fig.  142).  Ac- 
cording to  Hohnel 
these  structural  elements  are  only  0.3  to  1.5  microns  in  diameter;  they 
run  parallel  to  each  other  through  the  fiber,  and  are  rather  more  dense 
at  the  outer  portion  of  the  fiber  than  in  the  inner  part  (Fig.  143).  Besides 
the  fine  striations  on  the  fibers  of  wild  silk  caused  by  their  structural 
filaments,  there  are  also  to  be  noticed  a  number  of  irregularly  occurring 
coarser  striations.  These  latter  appear  to  be  due  to  air-canals,  or  spaces 
between  the  filaments  of  the  fiber.  i'-  • 

Hohnel  is  of  the  opinion  that  there  is  really  no  difference  in  kind 
between  the  structure  of  wild  silk  and  that  of  cultivated  silk ;  that  is  to  say, 
the  fibroine  fiber  of  the  latter  is  also  composed  of  structural  filaments, 
only  they  fuse  into  one  another  in  a  more  homogeneous  manner  on  emerging 


Fig.  142.— Tussah  Silk.  (X400.)  A,  View  of  broad  side; 
C,  cross-mark;  B,  cross-sections;  E,  torn  end  showing 
fibrillfB.     (Micrograph  by  author.) 


PHYSICAL  PROPERTIES  OF  SILK;    HYGROSCOPIC  NATURE     273 

from  the  fibroine  glands,  thus  rendering  it  more  difficult  to  recognise  them 
superficially.  This  view  is  upheld  somewhat  by  the  fact  that  a  slight 
striated  appearance  may  be  noticed  when  the  silk  fiber  is  macerated  in 
chromic  acid  solution.  This  apparent  structure  of  the  silk  fiber,  how- 
ever, may  also  be  due  to  another  cause.  If  a  plastic  glutinous  mass  (such 
as  melted  glue,  for  instance)  be  pulled  out  into  the  form  of  a  thread  and 
allowed  to  harden,  it  will  be  found  to  exhibit  the  same  striated  structure 
as  the  silk  fiber;  and  this  structure  will  be  more  apparent  if  the  thread  is 
pulled  out  and  hardened  more  rapidly.     The  liquid  fibroine  in  the  glands 


Fig.  143. — Cross-section  of  Wild  Silk.  A,  diagrammatic  drawing  of  section;  i,  air- 
space; g,  ground  matrix;  /,  fibrillae;  r,  marginal  layer;  B,  end  of  fiber  of  tussah 
silk  swollen  in  sulfuric  acid;  C,  cross-section  of  fiber  of  tussah  silk  swollen  in  sul- 
furic acid.     (After  Hohnel.) 


of  the  worm  is  a  plastic  glutinous  mass  analogous  to  melted  glue,  and  is 
pulled  out  into  the  form  of  a  thread  by  the  action  of  the  worm  in  winding 
its  cocoon ;  hence  it  would  be  natural  to  expect  a  striated  structure  similar 
to  that  observed  in  the  thread  of  glue.  Thus,  it  is  possible  to  account 
satisfactorily  for  the  structure  of  the  silk  fiber  in  a  perfectly  natural 
manner  without  having  recourse  to  a  very  doubtful  organic  process  in  the 
formation  of  the  fiber,  such  as  is  supposed  to  be  the  case  by  Hohnel. 

2.  Physical  Properties  of  Silk;    Hygroscopic  Nature. — Silk  is  quite 
hygroscopic,  and  under  favorable  circumstances  will  absorb  as  much  as 


274  PHYSICAL  PROPERTIES  OF  SILK 

30  percent  of  its  weight  of  moisture  and  still  appear  dry.  It  is  there- 
fore customary  to  determine  the  amount  of  moisture  in  each  lot  at  the 
time  of  sale.  This  is  called  conditioning,  and  is  usually  carried  out  in 
official  laboratories.  The  amount  of  "  regain  "  which  is  officially  per- 
mitted is  11  percent;  this  would  be  equivalent  to  9.91  percent  of  moisture 
in  the  silk.  Boiled-off  silk  appears  to  contain  somewhat  less  moisture 
than  raw  silk,  the  silk  gum  having  a  greater  attraction,  or  power  of  absorb- 
ing water,  than  the  fiber  proper.  The  amount  of  moisture  in  boiled-off 
silk  is  usually  regarded  as  about  8.45  percent,  which  would  correspond 
to  a  regain  of  9.25  percent.  The  Milan  Commission  (1906)  adopted  a 
temperature  of  140°  C.  for  the  conditioning  of  silk,  as  it  is  found  to  be 
difficult  to  completely  dry  the  fiber  at  110°-120°  C. 

3.  Electrical  Properties. — Being  a  bad  conductor  of  electricity,  silk 
is  readily  electrified  by  friction,  which  circumstance  at  times  renders  it 
difficult  to  handle  in  the  manufacturing  process.  The  trouble  can  be 
overcome  to  a  great  extent  by  keeping  the  atmosphere  moist.  Owing  to 
its  poor  conductivity  silk  is  largely  used  for  covering  insulated  wires  in 
electrical  apparatus. 

4.  Luster. — The  most  striking  physical  property  of  silk,  perhaps,  is  its 
high  luster.  The  luster  only  appears  after  the  silk  has  been  scoured  and 
the  silk-gum  removed.  The  luster  of  silk  is  affected  more  or  less  by  the 
various  operations  of  dyeing  and  mordanting,  and  especially  when  the  silk 
is  heavily  weighted.  After  dyeing,  especially  in  the  skein  form,  silk  usually 
undergoes  what  is  termed  a  lustering  operation,  which  consists  generally 
in  stretching  the  hanks  strongly  by  twisting,  and  simultaneously  steaming 
under  pressure  for  a  few  minutes.  This  process  seems  to  bring  back  to  a 
considerable  extent  the  luster  of  the  dyed  silk.  Lustering,  or  "  brighten- 
ing," may  also  be  accomplished  by  steeping  the  skeins  of  silk  in  a  solution 
of  dilute  acid,  such  as  acetic  or  tartaric,  squeezing,  and  drying  without 
washing.  The  luster  is  also  considerably  affected  by  the  method  of  dyeing 
and  the  chemicals  employed  in  the  dye-bath;  it  has  been  found  that  the 
addition  of  boiled-off  liquor  (the  soap  solution  of  sericine  obtained  in  the 
degumming  of  raw  silk)  to  the  dye-bath  has  the  result  of  preserving  the 
luster  of  the  dyed  silk  better  than  anything  else,  and  in  consequence 
boiled-off  liquor  is  nearly  always  employed  as  the  assistant  in  dyeing  in 
preference  to  glaubersalt  or  common  salt. 

The  lustering  of  silk  in  the  woven  fabric  is  brought  about  in  a  varietj'' 
of  ways  and  leads  us  into  the  many  processes  of  silk  finishing.  One 
process  which  is  very  extensively  employed  is  that  which  results  in  what 
is  known  as  a  "  moire,"  or  "  watered,"  finish. 

This  finish  is  produced  by  a  mechanical  process  which  transforms  the 
appearance  of  the  fabric.  The  fabrics  best  suited  to  receive  the  moire 
finish  are  those  in  which  the  weave  is  most  distinct.     The  process  is  chiefly 


LUSTER 


275 


used  for  finishing  silk  fabrics  such  as  poidt  de  sole,  gros  de  Tours  and 
fabrics  made  with  silk  warp  and  cotton  or  wool  filling,  that  is,  with  a  fine, 
closely  set  warp  and  a  fairly  coarse  filling.  This  finish  gives  to  the  cloth 
a  marblelike  effect  which  varies  in  form  and  aspect  according  to  the 
direction  from  which  it  is  examined.  The  operation  flattens  the  threads 
and  as  a  result  of  the  crushing  of  the  filling  at  certain  points  variable  lines 
and  shades  are  produced  arising  from  the  combination  of  surfaces  reflecting 
light  at  different  angles. 

The  discovery  of  this  finish  was  made  by  the  Chinese  who  enjoyed  a 
monopoly  of  it  for  a  long  time.  The  English  were  the  only  ones  to  employ 
it  in  Europe  previous  to  1754. 

There  are  two  processes  of  moire  finish :  moire  antique,  and  moire  ronde. 
Badger  introduced  in- 
to France  the  moire 
antique  finish  which  is 
still  called  English, 
while  the  other  finish 
is  called  French. 

For  the  moire  an- 
tique finish  the  cloth 
is  first  folded  so  as  to 
join  the  selvages, 
which  are  then  fast- 
ened by  sewing  at  in- 
tervals of  10  to  15 
ins.,  the  face  of  the 
cloth  being  inside.  If 
one  of  the  selvages  is 
longer  than  the  other 
it  is  slackened  before 
sewing  the  two  together  in  order  that  the  filling  may  be  held  in  its  normal 
position.  The  edge  of  the  fabric  is  then  cut  obliquely  with  scissors.  The 
finish  will  be  imperfect  if  the  selvages  stretch  more  than  the  body  of  the 
cloth.  After  doubling,  the  piece  is  folded  in  2-ft.  lengths,  one  fold  on  top 
of  the  other.  The  piece  is  now  placed  on  a  strong  linen  fabric  in  such  a 
way  that  the  folds  form  an  angle  of  45°,  as  shown  in  the  figure  (Fig.  144). 
In  other  words  the  folds  instead  of  being  superimposed  vertically  are 
arranged  so  that  the  ends  are  drawn  in  on  one  side  and  project  on  the  other. 
In  this  way  the  two  sides  of  the  folds  form  a  gradual  slant  terminating  in  a 
single  fold.  This  special  method  of  folding  is  called  "  dossage  oblique." 
The  fabric  thus  arranged  is  wound  on  a  roller  from  6  to  9  ins.  in  diameter 
and  is  then  covered  with  several  thicknesses  of  strong  cloth,  which  is  tied 
with  cords  at  the  ends.     The  roll  is  then  carried  to  the  mangle. 


Fig.  144.— Method  of  Folding  Silk  for  Moire  Finish. 


276  PHYSICAL  PROPERTIES  OF  SILK 

In  the  moire  effect  by  calender  finish,  a  hydraulic  calender  capable  of 
giving  pressures  of  over  100,000  lbs.  per  square  inch  is  used  and  the  calender 
rolls  are  heated.  In  one  process  the  piece  is  first  folded  and  the  selvages 
sewed.  When  two  filling  threads  come  directly  over  one  another  and 
pass  through  the  calender  the  increased  thicliness  thus  obtained  causes  a 
crushing  of  the  filling  threads.  On  the  other  hand,  the  filling  threads 
retain  their  round  form  on  the  other  parts  of  the  fabric.  There  are  quite 
a  variety  of  moire  finishes  depending  on  the  manner  of  passing  the  goods 
through  the  calender.  Also,  different  effects  may  be  obtained  by  using 
one  fabric  at  a  time,  or  by  using  two  pieces  of  the  same  cloth,  or  by  using 
two  different  fabrics.  Of  later  years  the  use  of  engraved  rollers  has  been 
introduced  and  in  this  manner  all  kinds  of  moire  patterns  and  effects  may 
be  obtained.  In  all  forms  of  moire  finish  the  luster  effect  is  produced  by 
the  fine  lines  or  striations  made  by  the  great  pressure  on  the  threads. 
This  character  of  surface  acts  in  much  the  same  manner  as  a  diffraction 
grating  and  diffracts  the  reflected  light.  Also,  the  smooth,  flat,  small 
surfaces  act  like  tiny  mirrors  in  reflecting  the  light  more  perfectly.  The 
wavelike  form  or  pattern  of  the  luster  gives  it  the  well-known  name  of 
"  watered"  silk. 

6.  Tensile  Strength  and  Elasticity. — Silk  is  also  distinguished  by  its 
great  strength.  It  is  said  that  its  tensile  strength  is  comparable  to  that 
of  an  iron  wire  of  equal  diameter.^  The  silk  fiber  is  also  very  elastic, 
stretching  15  to  20  percent  of  its  original  length  in  the  dry  state  before 
breaking.  Degummed  or  boiled-off  silk  is  somewhat  lower  in  strength 
and  elasticity  than  raw  silk,  the  removal  of  the  silk-gum  apparently 
causing  a  decrease  of  30  percent  in  the  tensile  strength  and  45  percent  in 
the  elasticity.  The  weighting  of  silk  also  causes  a  decrease  in  its  strength 
and  elasticity. 

The  table  on  page  277  gives  the  diameter,  elasticity,  and  tensile 
strength  of  the  cocoon-thread  of  the  chief  varieties  of  silk.^ 

6.  Density. — The  density  of  silk  in  the  raw  state  is  1.30  to  1.37,  while 
boiled-off  silk  has  a  density  of  1.25.  Silk,  therefore,  is  somewhat  lighter 
than  cotton,  linen  or  artificial  silk,  all  of  which,  being  cellulose  fibers, 
have  a  density  of  1.50.  Silk  is  also  slightly  lighter  than  wool  and  hair 
fibers  which  have  a  density  of  1.33  to  1.35.  The  figures  given  here  for  the 
density  of  silk  apply,  of  course,  to  the  pure  unweighted  fiber.  In  weighted 
silks  the  density  increases  with  the  degree  of  weighting,  as  the  metallic 
weighting  materials  all  have  a  much  higher  relative  density  than  the 
fiber  itself. 


1  The  breaking  strain  of  raw  silk  is  equivalent  to  about  64,000  lbs.  per  square  inch, 
or  nearly  one-third  that  of  the  best  iron  wire. 

2  Wardle,  Jour.  Soc.  Arts,  vol.  33,  p.  671. 


SCROOP 


277 


Diameter, 

Elasticity, 

Tensile 

Inches  in 

Strength, 

1  Foot. 

Drams. 

Size  of 

Name  of  Silk. 

Coiintry. 

Cocoon, 

Inches. 

Outer 

Inner 

Outer 

Inner 

Outer 

Inner 

Fibers. 

Fibers. 

Fibers. 

Fibers. 

Fibers. 

Fibers. 

Bombyx  mori 

China 

0.00052 

0.00071 

1.3 

1.9 

1.6 

2.6 

1.1X0.5 

Bombyx  mori 

Italy 

0.00053 

0.00068 

1.2 

1.9 

1.9 

2.6 

1.2X0.6 

Bombyx  mori 

Japan 

0.00057 

0.00069 

1.2 

1.4 

2.0 

3.1 

1.1X0.6 

Bombyx  fortunatus . 

Bengal 

0.00045 

0.00051 

1.8 

2.3 

1.6 

2.8 

1.2X0.5 

Bombyx  textor 

India 

0.00042 

0.00047 

1.5 

1.9 

1.4 

2.6 

1.2X1.5 

Anthersea  mylitta.. . 

India 

0.00161 

0.00172 

1.9 

2.7 

6.6 

7.8 

1.5X0.8 

Attacus  ricini 

India 

0.00085 

0.00093 

1.7 

2.0 

1.5 

3.0 

1.5X0.8 

Attacus  Cynthia .... 

India 

0.00083 

0.00097 

2.6 

2.9 

2.4 

3.5 

1.8X0.8 

Anthersea  assama . . . 

India 

0.00128 

0.00125 

2.4 

2.9 

2.8 

4.8 

1.8X1.0 

Attacus  selene 

India 

0.00100 

0.00109 

2.0 

2.8 

2.4 

4.0 

3.0X1.2 

Attacus  atlas 

India 

0.00102 

0.00111 

1.9 

2.8 

2.1 

4.1 

3.5X0.8 

Antheraja  yama-mai. 

Japan 

0.00088 

0.00096 

2.0 

4.0 

6.8 

7.5 

1.5X0.8 

Cricula  trifenestrata 

India 

0.00120 

2.0X0.8 

Antheraja  pernyi. . .  . 

China 

0.00118 

0.00138 

2.0 

2.7 

3.2 

5.8 

1.6X0.8 

7.  Scroop. — Another  property  of  silk,  and  one  which  is  pecuHar  to 
this  fiber,  is  what  is  termed  its  scroop;  this  refers  to  the  crackling  sound 
emitted  when  the  fiber  is  squeezed  or  pressed.  To  this  property  is  due 
the  well-known  rustle  of  silken  fabrics.  The  scroop  of  silk  does  not  appear 
to  be  an  inherent  property  of  the  fiber  itself,  but  is  acquired  when  the 
silk  is  worked  in  a  bath  of  dilute  acid  (acetic  or  tartaric)  and  dried  without 
washing.  A  satisfactory  explanation  to  account  for  the  scroop  has  not 
yet  been  given ;  it  is  probably  due  to  the  acid  hardening  the  surface  of  the 
fiber.  Mercerised  cotton  can  also  be  given  a  somewhat  similar  scroop 
by  such  a  treatment  with  dilute  acetic  acid.  Wool,  under  certain  con- 
ditions of  treatment,  in  some  degree  can  also  be  given  this  silk-like  scroop, 
as,  for  instance,  when  it  is  treated  with  chloride  of  lime  solutions  or  with 
strong  caustic  alkalies.  In  many  manufactured  articles  scroop  is  con- 
sidered as  a  desirable  property,  and  by  some  is  supposed  to  indicate  a 
high  quality  of  silk;  but  this  is  not  the  case,  as  the  scroop,  crunch  or  rustle 
of  silk  is  purely  an  acquired  property  added  by  artificial  treatment,  and 
it  does  not  enhance  the  real  value  and  quality  of  the  silk. 

8.  Silk  Reeling. — The  silk  fiber,  as  it  appears  in  trade  for  use  in  the 
manufacture  of  textiles,  is  obtained  by  um"eeling  the  cocoon.  After  the 
cocoons  have  been  spun  by  the  silkworms  they  are  heated  in  an  oven  for 
several  hours  at  a  temperature  of  from  60°  to  70°  C,  for  the  purpose 
of  killing  the  pupa  or  chrysalis  contained  within,  before  the  latter  shall 


278 


PHYSICAL  PROPERTIES  OF  SILK 


have  developed  sufficiently  to  begin  cutting  its  way  through  the  envelope 
and  thus  destroy  the  continuity  of  the  cocoon-thread.  Another  method 
of  operation  is  to  steam  the  cocoons ;  this  requires  only  a  few  minutes  to 
kill  the  pupa,  and  is  said  to  be  preferable  to  the  oven-heating,  as  it 
causes  less  damage  to  the  fiber,  and  at  the  same  time  considerably 
softens  the  silk-glue,  thus  rendering  the  subsequent  process  easier. 

After  the  killing  of  the  worms  is  accomplished,  the  cocoons  are  sorted 
into  several  grades,  according  to  size,  color,  extent  of  damage,  etc.,  after 
which  they  are  ready  for  reeling.  This  is  entirely  a  mechanical  process 
requiring  much  skill.  The  cocoons  are  soaked  in  warm  water  until  the 
silk-glue  is  softened;  the  operator  seizes  the  loose  ends  of  several  fibers 
together  on  a  small  brush  and  passes  them  through  the  porcelain  guides 


Fig.  145. — Showing  Methods  of  Reeling  the  Silk  Fiber  from  the  Cocoon. 


of  a  reel,  where  they  are  twisted  together  to  form  threads  of  sufficient 
size  for  weaving.  Two  threads  are  formed  simultaneously  on  each  reel, 
and  are  made  to  cross  and  rub  against  each  other  to  remove  twists  in  the 
fiber  (Fig.  145),  and  also  to  rub  the  softened  silk-glue  coverings  together 
in  order  that  the  fibers  may  become  firmly  cemented  and  form  a  uniform 
thread.  It  is  customary  in  most  filatures  to  reel  the  thread  of  five  cocoons 
together  into  a  single  yarn,  giving  a  raw  silk  of  13/15  denier. 

The  product  so  obtained  is  termed  raw  silk  or  grege.  Singles  is  the 
name  applied  to  all  raw  silk  composed  of  a  number  of  silk  filaments 
twisted  together  during  the  reeling  of  the  silk. 

Floss  silk,  which  is  used  for  making  spun  silk,  is  the  term  applied  to 
the  waste  resulting  from  short  and  tangled  fibers  from  the  exterior  of  the 
cocoon,  and  from  those  cocoons  which  have  been  broken  by  the  moth 
in  escaping.  In  the  practical  reeling  of  silk  three  cocoons  (six  filaments) 
make  about  the  finest  size  of  silk  that  can  be  commercially  employed; 
the  great  bulk  of  skein  silk,  however,  is  reeled  from  about  five  cocoons 


SILK  REELING  279 

(ten  filaments),  this  making  the  size  known  as  13/15  deniers.  The 
majority  of  the  raw  silk  of  commerce  is  now  reeled  into  skeins  of  standard 
circmiiference  and  of  a  convenient  weight,  and  the  skeins  are  generally 
reeled  with  a  quick  traverse  (Grant  reel)  so  that  a  broken  end  cannot  get 
lost  in  the  skein.  Reeled  silk  varies  much  in  character,  cleanliness, 
strength,  elasticity,  and  other  qualities.  Silk  reeled  in  summer  is  also 
generally  superior  to  spring  reeling  of  the  same  grade.  Raw  silk  in  the 
ungummed  state  can  be  employed  directly  in  only  a  limited  number  of 
fabrics,  as  in  the  warps  of  piece-dyed  cotton-back  satins.  Cultivated 
raw  silks  have  either  a  white  or  yellow  color;  generall}^  speaking,  all  the 
China,  Japan  and  Levantine  silks  are  white,  and  the  European  silks  are 
yellow. 

Yarns  made  from  spun  silk  differ  considerably  from  reeled  silk  in  being 
fuller,  bulkier,  and  softer,  they  have  less  luster  than  reeled  yarns,  are  not 
so  uniform,  and  cannot  be  spun  to  such  fine  counts.  Spun  silk  j-arns  are 
extensively  used  for  the  production  of  velvets  and  plushes^  for  striping 
and  checking  in  woolen  and  worsted  fabrics,  for  silk  handkerchiefs,  hosiery, 
laces,  etc.  Combination  yarns  are  also  largely  made  by  twisting  a  spun 
silk  thread  around  a  woolen,  worsted,  or  cotton  thread.  Spun  silk  yarns 
are  also  extensively  employed  as  a  warp  with  woolen,  worsted,  or  cotton 
filling  for  the  production  of  umbrella  cloth,  scarfs,  etc. 

Raw  silk  is  classified  into  two  grades:  (a)  Organzine  silk,  which  is  made 
from  the  best-selected  cocoons,  and  is  chiefly  used  for  warps  on  account 
of  its  greater  strength;  and  (6)  Tram  silk,  which  is  made  from  the  poorer 
quality  cocoons,  and  is  mostly  employed  for  filling. 

Tram  silk  is  the  union  of  two,  three,  or  more  singles,  only  slightly 
twisted  together,  and  is  known  as  2-thread,  3-thread,  etc.,  tram,  according 
to  the  number  of  singles  used  in  the  thread.  Tram,  as  a  rule,  is  used 
boiled-off,  and  only  rarely  in  the  gum,  being  degummed  before  dyeing 
in  the  hank.  Organzine  silk  is  the  union  of  a  2-thread  tram  yarn  with 
a  large  number  of  turns  per  inch  of  twist. 

Organzine  silk  is  made  for  warp  threads,  and  has  to  undergo  the 
processes  of  winding,  warping,  drawing  or  twisting,  and  weaving;  in  the 
loom  it  is  subjected  to  heavy  tension  and  has  to  withstand  the  chafing 
action  of  harness,  reed,  and  shuttle,  therefore  the  thread  must  be  clean, 
smooth,  well-knit  and  homogeneous.  To  make  organzine  it  is  cus- 
tomary to  twist  the  raw  silk  threads  together  with  16  turns  to  the  inch. 
Two  or  more  of  these  threads  are  then  doubled  together  and  twisted  12 
to  14  turns  per  inch  in  the  reverse  direction.  In  twisting  organzine  silk 
under  ordinary  conditions  it  is  fair  to  allow  from  4  to  5  percent  for  loss 
in  length  of  the  thread  owing  to  the  take-up  or  shortening  in  the  twisting 
of  the  threads.  For  hard-twist  silks  this  take-up  is  much  more,  being 
about  10  percent  for  45  turns  and  20  percent  for  70  turns  per  inch. 


280  PHYSICAL  PROPERTIES  OF  SILK 

Tram  silk  is  used  for  the  filling  or  weft  and  is  not  subjected  to  the 
friction  of  organzine  warp  threads;  it  would  be  undesirable  to  twist  it 
much,  as  the  woven  goods  would  then  feel  thin  and  sheer  and  not  have 
the  full  and  lofty  handle  required.  The  single  thread,  therefore,  is  given 
no  twist  at  all;  three  to  six  of  these  threads  are  doubled  together  and  a 
twist  of  2^  to  3^  turns  per  inch  put  in,  this  being  required  to  hold  the 
thread  together  in  the  dyeing  and  weaving,  while  at  the  same  time  it 
leaves  the  silk  full  and  open,  so  that  it  fills  the  cloth  properly. 

Some  silk,  such  as  that  used  for  chiffons,  is  twisted  very  hard,  up  to 
80  turns  per  inch  in  the  single,  and  is  used  in  that  form  for  both  warp 
and  filling. 

9.  Silk  Throwing. — Before  raw  silk  enters  into  manufacture  it  under- 
goes a  process  known  as  throwing.  This  is  a  mechanical  operation  in 
which  the  raw  silk  is  first  soaked  in  an  oil  or  soap  emulsion  to  soften  up 
the  fiber,  mthout,  however,  dissolving  the  silk-glue.  The  silk  is  then 
reeled  from  the  raw  skeins  so  that  several  fibers  are  brought  together, 
with  more  or  less  twist,  into  a  yarn  of  any  desired  size.  The  "  throwster," 
in  other  words,  simply  converts  the  raw  silk  yarn  into  a  yarn  of  proper  size 
for  manufacturing,  or  by  regulating  the  twist  produces  various  qualities 
of  silk  thread  for  the  several  purposes  required  for  the  weaving  or  knitting 
of  various  kinds  of  fabrics.  The  term  "  throwing"  is  apparently  derived 
from  an  Anglo-Saxon  word  ''  thraw,"  meaning  to  whirl  or  spin,  and  the 
word  in  this  connection  means  to  spin  or  twist  the  silk. 

Silk  throwing  requires  special  skill  and  knowledge  together  with  con- 
siderable plant  and  expensive  machinery,  and  consequently  it  has  devel- 
oped into  a  separate  and  distinct  business.  The  usual  commercial  practice 
is  for  the  manufacturer  to  buy  his  raw  silk  on  contract  from  the  silk 
importer;  it  is  then  shipped  to  the  throwster,  and  the  latter  in  turn,  after 
twisting  as  required,  sends  it  to  the  dyer  and  weighter,  who  then  sends 
it  back  to  the  manufacturer.  It  is  only  the  largest  silk  manufacturers 
who  combine  in  one  mill  the  separate  plants  for  throwing,  dyeing,  weight- 
ing and  manufacturing.- 

10.  Classification  of  Silk  Yams. — According  to  the  composition  and 
twist  of  the  threads,  silk  is  classified  into  the  following: 

1.  Organzine  (loarp  or  Orsey  silk);  from  3  to  8  cocoon  threads  are  lightly  twisted 
together  with  a  right-hand  twist,  so  that  there  are  from  60  to  80  turns  per  centimeter, 
and  2  to  3  such  threads  are  twisted  together  left-handed  to  form  double  or  threefold 
organzine. 

2.  Tram  or  weft  silk;  characterised  by  a  much  lower  degree  of  twist;  the  individual 

1  Current  prices  for  throwing  (1910)  have  been  about  65  cents  per  pound  for 
2-thread  13/15  denier  organzine,  with  5  cents  more  for  12/14  and  5  cents  less  for 
14/16  size.  For  tram  silk  about  35  cents  per  pound  for  4-,  5-,  or  6-thread,  37i  cents 
per  pound  for  3-thread  and  40  cents  for  2-thread. 


TESTS  FOR  CLASSIFICATION  OF  RAW  SILK  281 

threads  consisting  of  3  to  12  cocoon  threads  undergo  no  preHminary  twist,  and  2  or  3 
of  these  are  united  by  loose  twisting,  so  that  the  thread  is  softer  and  flatter  than 
organzine. 

3.  Marabout  silk;  used  for  making  crepe,  2,  to  3  threads  being  united  without  any 
preliminary  twisting,  then  dyed  without  scouring  and  strongly  twisted;  a  hard  twist 
and  stiffness  are  characteristic  of  this  silk. 

4.  "Soie  Ondee;"  prepared  by  doubling  a  coarse  and  a  fine  thread;  it  is  mostly 
used  for  making  gauze,  and  gives  a  moire  or  watered  appearance. 

5.  Cordonnet;  4  to  8  twisted  threads  are  combined  by  a  loose  left  twLst,  and  3  of 
the  threads  thus  formed  are  united  by  a  right-hand  twist;  this  silk  is  mostly  used 
for  selvages,  braiding,  crocheting,  knitting,  etc. 

,  6.  Sewing  silk;  made  from  raw  silk  of  3  to  24  cocoon  threads,  2,  4,  or  6  of  which 
are  united  by  twisting. 

7.  Embroidery  silk;  consists  of  a  number  of  simple  untwisted  threads  united  by 
a  slight  twisting. 

8.  Poil  or  single  silk;  a  raw  silk  thread  formed  by  twisting  8  to  10  cocoon  threads 
and  employed  for  making  gold  and  silver  tinsel. 

Floss  or  waste  silk  cannot  be  reeled,  so  the  cocoon-threads  are  scoured 
in  a  solution  of  soda  and  soap,  and  afterwards  combed  and  carded  in  special 
machines.  There  are  two  ways  in  which  waste  silk  may  be  degummed  for 
spinning:  it  may  either  be  boiled-off  or  chapped.  The  former  is  usually 
adopted  where  all  the  gum  is  to  be  removed,  and  is  carried  out  by  tying  the 
silk  up  in  bags  and  boiling  in  a  soap  solution.  In  the  second  method 
the  gum  is  loosened  by  a  process  of  fermentation  and  only  a  portion  of 
the  gum  is  removed  according  to  requirements.  The  process  is  carried 
to  such  perfection  that  as  much  as  15  percent  or  as  little  as  2  percent 
of  the  gum  may  be  removed.  In  chapping,  the  waste  silk  is  piled  in  a 
heap  in  a  damp,  warm  place,  and  kept  constantly  moist;  the  gum  soon 
begins  to  ferment  and  soften ;  by  continual  turning  of  the  pile  all  portions 
of  the  heap  are  properly  softened,  but  the  process  takes  several  days. 
Another  process  is  to  place  the  silk  in  cages  and  immerse  in  water  for 
several  days.  The  better  quality  and  longer  fiber  of  waste  silk  is  worked 
up  into  what  is  known  as  floreUe  silk,  while  the  shorter  fibers  are  carded 
and  spun  into  hourette  silk.  Floss  silk  is  also  known  as  chappe  or  echappe 
silk.     Silk  wadding  is  produced  from  the  waste  left  after  bourette  spinning. 

11.  Tests  for  Classification  of  Raw  Silk. — The  Silk  Association  of 
America  has  formulated  the  following  standard  tests  for  the  classification 
of  raw  silk: 

Article  1 

Section  1. — These  specifications  for  standard  tests  for  raw  silk  are  promulgated  by 
the  Silk  Association  of  America  for  the  purpose  of  standardising  the  official  methods 
of  testing  silk  in  the  United  States  in  order  to  facilitate  the  transactions  between 
buyers  and  sellers  of  silk,  and  to  furnish  the  producers  of  raw  silk  on  the  primary 
markets  accurate  information  upon  the  methods  by  which  the  characteristics  of  their 
products  are  to  be  determined  by  the  American  consumers.     While  the  test  methodi« 


282  PHYSICAL  PROPERTIES  OF  SILK 

herein  described  constitute  the  standard  tests  as  required  in  the  rules  and  regulations 
governing  transactions  on  raw  silk,  they  are  not  to  be  construed  as  waiving  the  right 
in  individual  cases  to  make  any  or  all  of  them  in  any  other  manner  or  to  make  such 
other  tests  as  may  be  desired.  They  shall  apply  and  govern  as  the  methods  to  be 
used  for  official  tests  by  the  United  States  Testing  Co.,  Inc.,  relating  to  contracts 
\mder  the  rules  and  regulations  of  the  Silk  Association  of  America  and  in  other  cases 
where  no  special  or  specific  methods  are  agreed  upon  and  are  contained  in  the  sales 
contracts. 

Section  2.  Definitions. — Raw  silk  is  the  single  thread  as  reeled  from  cocoons,  and  is 
understood  to  be  a  continuous  thread  from  beginning  to  end  of  the  skein.  The  skeins 
in  general  conform  in  weight,  circumference  and  lacing  to  the  specifications  for  the 
American  standard  skein  as  issued  and  approved  by  the  Silk  Association  of  America. 
Standard  Condition. — Where  the  expression  "standard  condition"  is  used  in  these 
specifications,  it  shall  be  understood  to  mean  the  condition  of  the  silk  when  it  con- 
tains 11  percent  of  its  dry  weight  of  moisture.  Standard  Atmosphere. — The  expression 
"standard  atmosphere"  shall  be  understood  to  mean  the  condition  of  the  air  such 
that  silk  placed  in  it  will  within  a  reasonable  period  assume  and  retain  a  standard 
condition.^ 

Section  3.  Sampling. — It  is  important  in  testing  by  means  of  samples  drawn  from 
the  merchandise  that  the  samples  should  be  so  selected  as  to  be  representative  of  the 
merchandise  and  that  a  sufficient  proportion  of  the  lot  should  be  sampled  to  be  repre- 
sentative of  the  entire  lot  to  which  the  tests  are  to  apply.  The  amount  of  sample 
and  the  number  of  samples  herein  specified  are  understood  to  be  the  minimum  which 
can  be  considered  as  representative  and  which  shall  constitute  an  official  sample  in 
size  and  distribution,  (a)  Sample  for  Test. — The  sample  for  a  test  shall  consist  of  at 
least  ten  average  original  skehis,  selected  at  random  from  different  parts  of  a  bale, 
not  more  than  one  skein  to  be  drawn  from  any  one  book  or  bimdle,  and  only  skeins 
from  a  single  bale  to  be  included  in  any  single  test.  Test  samples  for  two  or  more 
different  kinds  of  tests  may  be  taken  from  the  original  ten  skeins,  (b)  Sample  from 
Lot. — If  the  results  of  tests  are  to  represent  and  be  applied  to  a  lot,  at  least  two  tests 
must  be  made  upon  every  five  bales  of  the  lot,  one  from  each  of  two  bales  selected  at 
random. 

Article  2. — Winding  Test 

Section  1.  Object. — The  winding  test  is  intended  to  show  the  manner  in  which  the 
raw  silk  thread  will  pass  through  the  winding  operation. 

Section  2.  Sample. — The  sample  for  the  test  and  the  sampling  of  the  lot  is  as 
specified  in  Article  1,  Section  3.  Only  original,  intact  skei.is  drawn  fresh  from  the 
bale  shall  be  used. 

Section  3.  Apparatus. — The  winding  frame  upon  which  the  test  is  made  shall  run 
at  a  uniform  speed  and  be  capable  of  adjustment  to  the  following  average  thread 
speed,  120,  150,  180  yards  per  minute.  Standard  Bobbin. — To  insure  a  uniform 
tension  and  speed  the  bobbin  should  have  the  following  dimensions: 

Diameter  of  head 50  mm.  (2  inches) 

Diameter  of  drum 46  mm.  (1|  inches) 

Length  between  heads 75  mm.  (3  inches) 

^  A  relative  humidity  of  65  percent  at  a  temperature  between  65°  F.  and  70°  F. 
produces  an  approximate  standard  atmosphere.  If  the  temperature  rises  above  70°  F. 
the  relative  humidity  must  also  increase  to  maintain  the  regain  at  11  percent. 


TESTS  FOR  CLASSIFICATION  OF  RAW  SILK  283 

The  bobbins  should  be  constructed  so  as  to  be  Hght,  well  balanced,  and  smooth, 
and  should  revolve  smoothly  without  jumping.  Swifts. — The  swifts  (tavelle)  used  in 
the  test  should  be  self-centering,  geared-hub  pin  swifts  without  weights  or  twelve  stick 
pin-hub  swifts  without  weights. 

Section  4-  Skeiris. — The  sample  skeins  shall  be  put  on  the  swifts  with  care  to 
insure  that  each  skein  is  in  good  condition.  A  record  should  be  made  of  the  degree 
of  gum  spots  if  any  are  present.  Five  skeins  shall  be  wound  from  the  top  and  five 
from  the  bottom.  Speed  of  Winding. — The  average  thread  speed  of  winding  shall  be 
adjusted  according  to  the  average  size  of  the  raw  silk  and  shall  be  regulated  as  nearly 
as  possible  to  the  following  speeds: 

Of  59"  Skein. 

Below  13  denier 120  yards  per  minute  =  73  R.P.M. 

13  denier  to  17  denier 150  yards  per  minute  =  92  R.P.M. 

Above  17  denier 180  yards  per  minute  =  110  R.P.M. 

The  maximum  thread  speed  of  winding  at  the  completion  of  the  test  shall  not 
exceed  the  following: 

Of  59"  Skein. 

Below  13  denier 140  yards  per  minute  =  85  R.P.M. 

13  to  17  denier 170  yards  per  minute  =  104  R.P.M. 

Above  17  denier 200  yards  per  minute  =  122  R.P.M. 

Winding. — During  the  winding  test,  the  winding  laboratory  shall  be  maintained 
at  as  nearly  a  standard  atmosphere  as  possible.  First  Period. — The  skeins  should  be 
wound  onto  spare  bobbins  for  fifteen  (15)  minutes.  They  should  then  be  inspected  to 
determine  if  any  are  in  bad  condition  due  to  damage,  mishandling  or  improper  putting 
on.  If  any  skeins  are  found  to  be  in  bad  condition  due  to  causes  other  than  poor 
reeling,  they  shall,  provided  they  do  not  exceed  two  in  number,  be  omitted  from  the 
test,  which  shall  be  completed  on  the  remaining  skeins.  If  they  do  not  exceed  two 
in  number,  additional  samples  shall  be  drawn  to  replace  the  damaged  ones.  Second 
Period. — The  spare  bobbins  shall  then  be  replaced  by  standard  bobbins  and  the  winding 
continued  until  the  standard  bobbin  for  each  skein  is  filled  flush  with  the  heads,  care 
being  taken  to  insure  proper  traverse  to  wind  a  smooth,  compact  bobbin. ^ 

Section  8.  Records.  First  Period. — ^A  separate  record  shall  be  kept  of  the  number  of 
breaks  occurring  in  the  first  fifteen  minutes  and  special  note  made  of  excessive  breaks 
in  any  particular  skeins,  stating  the  cause.  Second  Period. — After  the  inspection  of 
the  skeins,  a  record  shall  be  kept  of  the  breaks,  and  special  attention  given  to  any  skeins 
showing  an  excessive  number  of  breaks.  Weighing. — When  the  bobbins  are  filled  the 
raw  silk  will  be  re-reeled  without  waste  into  skeins,  placed  for  at  least  two  hours  in  a 
space  maintained  at  a  standard  atmosphere  so  that  they  will  regain  moisture  to  the 
standard  condition.  They  will  then  be  weighed  in  grams,  and  the  number  of  breaks 
per  100  grams  calculated  by  proportion.  The  breaks  per  100  grams  may  be  con- 
verted into  approximate  breaks  per  pound  by  multiplying  by  4.5. 

Section  10.  Rating  in  Percentage. — The  winding  may  be  expressed  in  percentage  by 
assuming  one  break  per  100  grams  as  1  per  cent  and  subtracting  the  number  of  breaks 
from  100  percent. 

^  The  second  period  should  require  about  one  hour  for  a  14  denier  raw  silk  and 
yield  about  10,000  yards  from  each  skein,  or  100,000  yards  (100  grams)  for  the  test. 
Other  sizes  will  require  proportionately  other  yardages  to  fUI  the  standard  bobbms. 


284  PHYSICAL  PROPERTIES  OF  SILK 


Article  3. — Sizing  Test  (450  meter) 

Section  1.  Object. — The  sizing  test  is  intended  to  determine  the  average  size,  i.e., 
the  weight  in  deniers  of  the  raw  silk  thread  per  450  meters.  One  denier  equals  5  centi- 
grams. 

Section  2.  Apparatus. — The  measuring  machine  for  making  the  450-meter  sizing 
skeins  shall  have  a  reel  112§  centimeters  in  circumference  (400  revolutions  =  450  meters), 
revolving  at  a  uniform  velocity  of  300  revolutions  per  minute;  provided  with  a  dial 
showing  the  number  of  revolutions  and  equipped  with  an  automatic  stop  motion  to 
stop  the  reel  abruptly  in  case  the  thread  breaks  and  when  the  skein  is  complete.  The 
balance  for  determining  the  total  weight  of  the  skeins  shall  be  capable  of  being  read 
to  5  centigrams.  The  balance  for  weigliing  the  individual  test  skeins  should  be  of  the 
quadrant  type,  graduated  in  |  deniers. 

Section  3.  Samples. — The  sample  for  the  test  and  the  sampling  for  the  lot  shall  be 
taken  as  specified  in  Article  1,  Section  3. 

Section  4-  Test. — From  the  ten  sample  skeins,  ten  bobbins,  one  from  each  skein, 
shall  be  wound,  five  from  the  outside  and  five  from  the  inside.  The  ten  bobbins  shall 
be  placed  upright  on  the  measuring  machine,  and  three  test  skeins,  450  meters  each, 
reeled  from  each  bobbin,  a  total  of  30  sizing  skeins.  The  sizing  test  skeins,  may  be 
taken  from  the  bobbins  woimd  in  the  winding  test  if  desired.  The  room  in  which  the 
reel  is  located  should  have  temperature  and  humidity  control  regulated  to  maintain 
a  standard  atmosphere,  and  the  silk  should  be  in  as  nearly  standard  condition  as 
possible  at  the  time  of  reeling.  The  tension  on  the  thread  should  be  sufficient  to 
hold  it  taut  without  excessive  stretching.  Care  should  be  exercised  to  see  that  no 
short  test  skeins  are  reeled  by  the  stop  motion  failing  to  act  quickly  upon  breaking 
of  thread  or  long  skeins  by  running  over  400  revolutions.  The  sizing  skeins  which 
lose  moisture  during  reeling  should  be  allowed  to  remain  in  the  standard  atmosphere 
for  a  sufficient  time  (about  one  hour)  to  allow  them  to  return  to  standard  condition, 
and  then  they  should  be  weighed  as  follows:  (a)  Regular  Sizing. — If  the  standard 
condition  assumed  by  the  sizing  skeins  in  the  reeling  room  is  sufficiently  accurate, 
the  thirty  skeins  should  be  weighed  together  and  their  final  weight  expressed  in  deniers. 
Each  skein  should  then  be  weighed  on  a  quadrant  balance  to  the  nearest  half  denier, 
and  the  sum  of  the  individual  weighings  should  not  differ  from  the  total  weight  by  more 
than  one-half  (i)  denier,  (b)  Conditioned  Sizing. — If  a  more  accurate  average  size 
than  the  regular  sizing  is  desired,  the  sizing  skeins  should,  after  completion  of  the 
regular  sizing,  be  placed  together  in  a  conditioning  oven,  dried  to  constant  weight 
at  130°  C.-140°  C,  and  weighed  in  the  dry,  hot  atmosphere. 

Section  5.  Record.- — The  record  should  show  the  number  of  sample  skeins  drawn; 
the  number  of  sizing  skeins  reeled  and  weighed;  the  total  weight  of  the  test  skeins 
in  deniers;  the  average  weight  per  skein,  i.e.,  the  average  size  in  deniers;  the  weight 
of  the  individual  skeins  arranged  in  the  order  of  increasing  magnitude,  and  the  sum 
of  the  individual  weighings.  Corulitumed  Sizing. — -In  addition  to  the  record  made  for 
the  regular  sizing,  the  record  of  the  conditioned  sizing  should  show  the  total  dry 
weight  in  deniers,  the  total  conditioned  weight  in  deniers  (i.e.,  the  dry  weight  plus 
11  percent),  and  the  average  conditioned  weight  per  test  skein,  i.e.,  the  average  con- 
ditioned size  in  deniers. 

Article  4- — American  Sizing  Test  (225  meter) 

Section  1.  Object. — The  American  sizing  test  is  intended  to  determine  the  variation 
in  weight,  in  deniers,  of  225-meter  lengths  of  the  thread,  the  average  weight  in  denier 
of  225  meters  of  the  thread  and  the  average  size,  i.e.,  the  weight  in  deniers  per  450  meters. 


TESTS  FOR  CLASSIFICATION  OF  RAW  SILK  285 

Range. — The  range  for  a  test  is  the  difference  in  deniers  between  the  weight  of  the 
Ughtest  and  heaviest  225-meter  test  skein  in  the  test.  The  range  for  a  lot  is  the 
difference  between  the  Hghtest  and  heaviest  test  skein  in  the  lot. 

Section  2.  Apparatus. — The  measuring  machine  for  making  the  225-meter  test 
skeins,  the  balance  for  determining  their  total  weight,  and  the  balance  for  weighing 
the  individual  skeins  shall  be  as  specified  for  the  sizing  test.     (Art.  3,  Sec.  2.) 

Section  3.  Samples. — The  sample  for  the  test  and  sampling  for  the  lot  shall  be  taken 
as  specified  in  Article  1,  Section  3. 

Section  4-  Test. — From  the  ten  sample  skeins,  ten  bobbins  (one  from  each  skein) 
shall  be  wound,  five  from  the  outside  and  five  from  the  inside.  The  ten  bobbins  shall 
be  placed  upright  on  the  reeling  machine,  and  six  test  skeins,  225  meters  each,  reeled 
from  each  bobbin,  a  total  of  sixty  test  skeins.  The  test  skeins  may  be  taken  from 
the  bobbins  wound  in  the  winding  test  if  desired.  The  room  in  which  the  reel  is 
located  should  have  temperature  and  humidity  control  regulated  to  maintain  standard 
atmosphere  and  the  silk  be  in  as  nearly  standard  condition  as  possible  at  the  time  of 
reeling.  The  test  skeins  which  lose  moisture  during  reeling  should  be  allowed  to 
remain  in  the  standard  atmosphere  for  a  sufficient  time  (about  one  hour)  to  allow 
them  to  return  to  standard  condition  and  then  they  should  be  weighed  as  follows: 
Weighing. — The  sixty  test  skeins  should  be  weighed  together  and  their  total  weight 
expressed  in  deniers.  Each  skein  should  then  be  weighed  on  a  quadrant  balance  to 
the  nearest  half  denier.  Conditioned  Sizing. — If  the  conditioned  size  is  desired  the 
skeins  may  then  be  placed  in  a  drying  oven,  dried  to  constant  weight  at  130°  C.  to 
140°  C,  and  weighed  in  the  dry,  hot  atmosphere. 

Section  5.  Record. — The  record  should  show  the  number  of  sample  skeins  drawn; 
the  number  of  test  skeins  wound;  the  total  weight  of  the  test  skeins;  the  average 
weight  of  the  test  skeins;  the  weight  of  the  individual  test  skeins  arranged  in  order 
of  increasing  magnitude;  the  sum  of  the  individual  test  skeins  and  the  difference 
between  the  weight  of  the  lightest  and  heaviest  test  skeins  expressed  in  deniers,  i.e., 
the  range.  The  average  size  may  be  calculated  by  multiplying  the  average  weight  of 
the  test  skeins  by  two  or  by  dividiiig  the  total  weight  of  the  sixty  skeins  by  30.^ 

Article  5. — Gage  Test 

Section  1.  Object. — The  gage  test  is  intended  to  measure  the  reeling  defects  in 
raw  silk  and  consists  of  a  determination  of  the  number  and  kind  of  defects  in  a  given 
length  of  the  thread. 

Section  2.  Apparatus. — The  gage  consists  of  two  pieces  of  hardened  tool  steel 
approximately  6^  inches  long,  1  inch  wide,  and  \  inch  thick.  One  narrow  side  of 
each  piece  is  ground  accurately  to  a  plane  straight  surface  and  the  two  pieces  are  bolted 
together  so  that  the  plane  surfaces  form  a  very  narrow  V-shaped  slit.  The  gage  is 
graduated  to  read  in  deniers  by  determining  fixed  points  at  which  the  width  of  the 
V-slit  is  equal  to  the  calculated  diameter  of  raw  silk  of  a  selected  denier  and  by  dividing 
the  distance  along  the  gage  into  equal  spaces.     Ten  gages  constitute  a  set  which  is 

1  The  range  found  for  225-meter  skeins  cannot  be  converted  into  the  "spring" 
("ecart")  in  450-meter  skeins  by  multiplying  by  2  nor  by  doubling  the  weight  of 
the  lightest  and  heaviest  225-meter  skein  and  taking  their  difference.  Such  a  cal- 
culation would  assume  that  the  extreme  fine  and  coarse  portion  from  which  the  lightest 
and  heaviest  225-meter  skeins  were  reeled  continued  for  another  225  meters.  This  is 
not  a  safe  assumption  for  the  reason  that  the  "spring"  (ecart)  determined  by  the 
450-meter  sizing  test  is  always  less  than  double  the  range  found  by  the  225-meter  test 
upon  the  same  silk. 


286 


PHYSICAL  PROPERTIES  OF  SILK 


mounted  on  a  reeling  machine  in  such  a  manner  as  to  be  adjusted  to  allow  the  silk 
as  it  passes  through  guides  from  bobbins  on  to  a  measuring  reel,  to  run  through  the 
gages  at  its  average  denier  as  determined  by  a  sizing  test. 

Section  3.  Evenness  Defects. — (a)  Weak  threads  (tender  or  fine)  are  those  which 
break  30  percent  to  50  percent  below  the  average  strength  of  the  thread,  (b)  Very 
weak  threads  (tender  or  fine)  are  those  which  break  50  percent  or  more  below  the 
average  strength  of  the  thread,  (c)  Coarse  threads  are  those  which  catch  and  break 
in  the  gages  and  of  which  the  strength  is  30  percent  to  50  percent  above  the  average 
strength  of  the  thread,  (d)  Very  coarse  threads  are  those  which  catch  and  break  in 
the  gages  and  of  which  the  strength  is  50  percent  or  more  above  the  average  strength 
of  the  thread. 

Section  4-  Cleanness  Defects. — On  account  of  the  unequal  importance  of  the  different 
cleanness  defects  in  the  manufacturing  and  finishing  processes  and  in  their  effect  upon 

the  ciuality  of  the  finished  goods,  cleanness 
defects  are  divided   into  two   classes,  viz., 
major  defects  and  minor  defects. 
(a)  Major  Defects: 

(1)  Waste  is  a  mass  of  tangled  open  fiber 
attached  to  the  raw  silk  thread. 

(2)  Slugs  are  thickened  places  several 
times  the  diameter  of  the  thread,  of  |  inch 
or  over  in  length. 

(3)  Bad  casts  are  abruptly  thickened 
places  on  the  threads  due  to  the  cocoon 
filament  not  being  properly  attached  to  the 
thread. 

(4)  Split  threads  are  large  loops,  loose 
ends,  or  open   places   on  the  thread  where 

one  or  more  cocoon  filaments  are  separated  from  the  thread. 

(5)  Very  long  knots  are  knots  which  have  loose  ends  exceeding  |  inch  in  length. 

(6)  Corkscrews  are  places  on  the  thread  where  one  or  more  cocoon  filaments  are 
longer  than  the  remainder  and  wrap  around  the  thread  in  spiral  form. 

(b)  Minor  Defects: 

(1)  Nibs  are  small  thickened  places  less  than  |  inch  in  length. 

(2)  Loops  are  small  open  places  in  the  thread  caused  by  the  excessive  length  of  one 
or  more  cocoon  filaments. 

(3)  Long  knots  are  knots  which  have  loose  ends  from  5  to  §  inch  in  length. 

(4)  Raw  knots  are  the  necessary  knots  for  tying  breaks  in  the  raw  silk  thread 
during  the  reeling  and  re-reeling  operation.  The  ends  of  the  knot  should  be  less  than 
I  inch  long.  The  number  of  raw  knots  should  be  recorded,  but  they  should  not  be 
counted  among  the  defects. 

Section  5.  Samples. — The  sampling  for  the  test  and  the  sampling  of  the  lot  shall  be 
as  specified  in  Article  1,  Section  3. 

Section  6.  Winding. — Sufficient  silk  for  the  test  shall  be  wound  from  the  sample 
skeins  onto  bobbins  under  the  same  conditions  as  specified  in  the  winding  test  in 
Article  2,  Sections  3  and  4.  A  record  shall  be  kept  of  the  number  of  winding  breaks 
and  care  should  be  exercised  to  tie  all  winding  breaks  without  removing  any  of  the 
thread,  with  a  distinguishing  knot  (bow  knot)  in  a  manner  to  be  easily  recognised. 
The  silk  wound  onto  bobbins  in  the  winding  test.  Article  2,  may  be  used  for  the  gage 
test,  provided  care  is  exercised  to  tie  all  winding  breaks  with  a  distinguishing  knot 
(bow  knot)  so  that  the  nature  of  the  defect  causing  the  winding  break  may  be  deter- 
mined and  recorded. 


Fig.  146. — Seem  Apparatus  for  Testing 
the  Cohesion  of  Raw  Silk. 


TESTS  FOR  CLASSIFICATION  OF  RAW  SILK  287 

Section  7.  Test. — The  bobbins  shall  be  placed  upright  on  the  gage  reeling  machine 
and  the  ends  of  the  threads  passed  through  guides  and  the  gages  with  just  sufficient 
tension  to  keep  the  thread  taut.  The  gages  shall  be  adjusted  to  such  a  position  that 
the  thread  will  run  through  them  at  the  average  size.  The  thread  speed  should  be 
approximately  250  yards  per  minute.  When  the  thread  breaks  the  reel  should  be 
stopped  and  both  ends  of  the  thread  examined  to  determine  the  kind  of  defect  as 
defined  by  Section  3  of  this  article,  and  illustrated  by  standard  photograph  adopted 
by  the  Silk  Association  of  America.  If  either  portion  appears  fine  or  coarse  it  should 
be  tested  on  a  serimeter  to  determine  if  it  is  an  evenness  defect.  (Section  3  (a),  (b), 
(c),  (d).)  When  1,000  yards  have  been  wound  from  each  of  the  ten  bobbins 
(10,000  yards  in  all),  the  reel  should  be  stopped  and  a  record  made  of  the  number  of 
defects  in  each  class.  The  test  should  be  continued  until  a  total  of  30,000  yards  has 
been  reeled,  stops  and  records  being  made  of  each  10,000  yards. ^ 

Sedian  8.  Records. — The  records  of  the  test  shall  show  the  number  of  each  defect 
for  each  10,000  yarda  reeled,  the  total  number  of  each  defect  for  the  total  number  of 
yards  tested,  and  the  number  of  defects  of  each  kind  calculated  for  100,000  yards.^ 

Article  6. — Serimeter  Test  for  Evenness 

Section  1 .  Object. — The  serimeter  test  for  evenness  is  made  to  determine  the  variation 
of  the  breaking  points  of  one  hundred  different  portions  of  the  raw  silk  thread  from 
the  average  breaking  point  foimd  by  taking  the  average  of  the  himdred  points  tested. 

Section  2.  Apparatus. — The  serimeter  used  for  the  test  must  be  sensitive  and 
capable  of  being  read  to  one  gram  and  have  a  maximum  capacity  of  250  grams.  It 
must  be  provided  with  a  type  of  clip  which  does  not  cut  the  thread.  The  pulling  clip 
of  the  testing  machine  shall  move  at  a  uniform  speed  of  80  centimeters  per  minute. 

Section  3.  Sample. — The  sampling  for  the  test  and  the  sampling  of  the  lot  shall  be 
as  specified  in  Article  1,  Section  3.     The  test  shall  be  made  upon  ten  sizing  skeins. 

Section  4-  Test. — Each  sizing  skein  should  be  cut  once,  and  from  each  of  the  ten 
sizing  skeins  ten  strands  shall  be  selected  at  random  and  examined  to  see  that  they 
appear  to  be  clean  threads  (i.e.,  contain  no  cleanness  defects  as  defined  and  illustrated 
in  Article  5).  The  strands  shall  be  placed  in  the  serimeter,  inspected  again  to  make 
sure  they  are  clean,  and  the  breaking  point  determined.  Any  strands  found  to  contain 
cleanness  defects  should  be  replaced  by  clean  ones,  and  strands  which  break  in  the 
clips  should  not  be  counted.  The  length  of  thread  between  the  clips  at  the  beginning 
of  each  test  shall  be  50  centimeters. 

1  The  operator  should  see  that  no  waste  or  loose  matter  collects  on  the  gages  to 
interfere  with  the  passage  of  the  thread,  and  care  should  be  exercised  to  keep  the  gages 
clean,  well  coated  with  oil  to  avoid  rusting  and  protected  with  covers  when  not  in 
use.  The  gages  should  be  frequently  tested  to  determine  if  the  width  of  the  slit  is 
correct. 

^  To  express  the  final  result  of  the  test  in  a  single  number  of  defects,  the  various 
defects  must  be  included  in  the  final  result  in  accordance  with  their  relative  importance. 

The  following  multiplying  factors  are  suggested  for  this  purpose: 

Evenness  Defects. — Weak  threads  and  coarse  threads  may  be  taken  as  counted. 

Very  weak  threads  should  be  multiplied  by  three. 

Very  coarse  threads  should  be  multiplied  by  two. 

Cleanness  Defects. — Major  defects  are  to  be  taken  as  counted. 

Minor  defects  are  to  be  considered  as  one-tenth  defect  and  their  number  should  be 
divided  by  ten. 


288  PHYSICAL   PROPERTIES  OF  SILK 

Section  5.  Record. — The  breaking  point  of  each  strand  should  be  read  and  recorded 
to  the  nearest  five  grams,  the  values  being  arranged  in  the  order  of  increasing  magni- 
tude. The  record  should  show  the  frequency,  i.e.,  the  number  of  breaks  at,  above, 
and  below  the  average  breaking  point. ^ 

Article  7. — Serigraph  Test 

Section  1.  Object. — The  serigraph  test  is  designed  to  determine  the  tenacity,  elas- 
ticity and  elongation  of  raw  sUk.^ 

Definitions. — The  three  physical  characteristics  determined  in  this  test  are  defined 
as  follows:  Tenacity  is  the  strength  of  a  single  thread  expressed  in  grams  per  denier. 
Elasticity  is  the  limiting  force  expressed  in  grams  per  denier  which  the  thread  will  just 
support  without  permanent  elongation.  It  is  indicated  in  the  test  by  the  yield  point 
on  the  serigraph  record  at  which  the  straight  line  portion  ends  and  the  diagram  becomes 
curved.  Elongation  (heretofore  called  elasticity)  is  the  amount  that  the  silk  is 
stretched  when  pulled  to  the  breaking  point. 

Section  2.  Apparatus. — The  apparatus  for  the  test  consists  of  a  tensile  strength 
testing  machine  with  an  autographic  attachment  recording  simultaneously  the  pulling 
force  and  the  corresponding  elongation  of  the  thread.  The  machine  must  be  located 
in  a  room  having  humidity  and  temperature  control  and  must  be  capable  of  being 
tested  for  correctness  of  reading  by  direct  loading  with  standard  weights.  The  total 
capacity  of  the  machine  should  not  be  greater  than  twice  the  ultimate  strength  of  the 
specimen  to  be  tested.  The  uniform  speed  of  the  pulling  jaw  should  be  15  centimeters 
(6  inches)  per  minute. 

Section  3.  Sample. — The  sample  for  the  test  and  the  sampling  for  the  lot  shall  be 
taken  as  specified  in  Article  1,  Section  3.  The  test  sample  shall  consist  of  ten  sizing 
skeins.  The  450-meter  skeins  used  in  the  sizing  test  or  the  225-meter  skeins  used  in 
the  American  sizing  test  maj^  be  used,  but  in  either  case  the  skeins  should  not  be  twisted 
tight  enough  to  injure  the  gum,  and  the  skeins  should  be  opened  and  allowed  to  hang 
loose  for  some  time  before  being  tested  in  the  serigraph.  Sizing  skeins  which  have 
been  used  for  a  conditioned  sizing,  Article  3,  Section  4,  cannot  be  used  in  this  test  on 
account  of  the  possible  changes  in  the  physical  properties  of  the  thread  which  may 
have  taken  place  due  to  the  heating  in  the  conditioning  oven. 

Section  4-  Test. — The  test  skeins  shall  be  placed  in  a  space  in  which  the  relative 
humidity  and  temperature  can  be  regulated  to  the  standard  condition  and  they  shall 
remain  a  sufficient  time  (usually  one  to  two  hours)  to  allow  them  to  become  adjusted 
to  a  standard  condition.  Each  skein  should  then  be  carefully  weighed  to  the  nearest 
I  denier,  placed  in  the  recording  serigraph  and  tested  for  tenacity,  yield  point  and 

1  The  following  arrangement  will  be  foimd  simple,  convenient,  and  easily  inter- 
preted. The  report  blank  should  have  a  portion  ruled  both  horizontally  and  vertically. 
Each  space  from  the  top  downward  may  be  taken  equal  to  5  grams,  and  each  space  across 
the  sheet  equal  to  5  strands.  Assigning  values  to  the  spaces  vertically,  the  breaking 
point  of  the  individual  strands  may  be  tallied  beside  their  corresponding  values,  and 
at  the  completion  of  the  test  the  total  number  of  tallies  for  each  breaking  point  can 
be  entered  in  an  adjoining  space.  A  graphical  representation  of  the  result  of  the  test 
can  be  easily  made  by  drawing  at  each  breaking  point,  horizontally  from  a  fixed 
vertical  line,  a  heavy  line  with  its  length  indicating  the  number  of  strands  breaking 
at  that  point. 

2  As  a  raw  silk  thread  is  pulled,  it  stretches  at  first  proportionally  to  the  pulling 
force,  and  if  the  pulling  force  is  relieved  the  thread  will  return  to  its  original  length. 
If  the  force  continues  to  increase,  it  will  reach  a  point  at  which  the  thread  begins  to 
stretch  more  rapidly  and  to  be  permanently  stretched. 


TESTS  FOR  CLASSIFICATION  OF  RAW  SILK  289 

elongation.  1  The  length  of  the  tested  portion  should  be  10  cm.  between  the  clamps 
of  the  machine  when  the  test  begins.  Care  should  be  exercised  to  prevent  the  portion 
of  the  skein  which  is  outside  of  the  clamps  from  supporting  any  portion  of  the  pulling 
force. 

Section  5.  Record. — The  autographic  record  should  show  a  diagram  from  which  the 
breaking  load  and  elongation  at  any  point  during  the  test  can  be  read  with  an  accuracy 
of  5  percent,  and  the  final  reading  on  the  dial  of  the  testing  machine  should  check  with 
the  breaking  load,  as  shown  on  the  autographic  diagram.  By  placing  a  ruler  along 
the  straight  line  portion  of  the  diagram,  the  point  at  which  the  diagram  begins  to 
depart  from  a  straight  line  can  be  marked.  This  point  will  be  called  the  yield  point. 
The  pulling  force  at  the  yield  point,  divided  by  the  number  of  strands,  divided  by  the 
weight  of  the  skeins  in  deniers,  is  called  the  elasticity  of  the  silk  and  is  expressed  in 
grams  per  denier.  The  total  stretch  to  the  breaking  point,  divided  by  the  original 
length,  is  the  elongation  and  should  be  expressed  in  percent.  The  tabulated  record 
shall  show  the  following  for  each  skein : 

(a)  The  number  of  strands  tested. 

(b)  The  weight  of  the  skein  in  deniers. 

(c)  The  breaking  force  in  grams. 

(d)  The  tenacity,  i.e.,  the  grams  per  denier. 

(e)  The  elasticity,  i.e.,  the  pulling  force  in  grams  at  the  per  denier  at  the  yield  point. 

(f)  The  elongation,  in  percentage. 

For  the  entire  test  of  ten  skeins:  The  average  tenacity,  the  average  elasticity,  the 
average  elongation. 

Article  8. — Cohesion  Test  (By  Seem's  Cohesion  Machine) 

Section  1.  Object. — The  cohesion  test  is  intended  to  determine  the  compactness  of 
the  raw  silk  thread  and  the  thoroughness  with  which  the  cocoon  filaments  forming  the 
thread  have  been  agglutinated.  It  is  based  upon  the  amount  of  rolling  and  rubbing 
under  constant  pressure  which  the  thread  will  withstand  before  sphtting  into  its 
individual  cocoon  filaments. 

Section  2.  Apparatus. — The  Seem  cohesion  machine  consists  of  a  hardened  steel 
roller  accurately  ground  and  polished,  approximately  I  inch  in  diameter,  mounted  on 
a  steel  arm  which  is  hinged  at  one  end  and  which  acts  as  the  weight  to  produce  pressure 
on  the  roller.  Under  the  roller  a  steel  carriage,  mounted  between  guides,  moves  back 
and  forth  a  distance  of  about  2  inches.  The  carriage  is  fitted  with  two  clamps  for 
holding  the  specimens,  and  a  counter  indicates  the  number  of  strokes  which  the  car- 
riage makes  during  the  test.  The  roller  is  set  at  an  angle  of  2.5  degrees  to  the  path 
of  movement  of  the  carriage  so  that  the  thread  is  submitted  to  a  rolling  and  rubbing 
action.  2 

^  The  skein  must  be  secured  in  the  clamps  of  the  serigraph  in  such  a  manner  that 
all  strands  are  held  firmly  and  none  of  the  threads  are  cut  by  the  pressure  of  the  clamps 
or  any  sharp  edges.  This  can  be  easily  accomphshed  by  wrapping  all  of  the  strands 
around  a  strip  of  soft  cardboard  and  placing  the  cardboard  in  the  clamps  of  the 
machine  in  such  a  manner  that  all  strands  are  securely  held  but  not  crushed.  It  is 
convenient  to  place  the  test  specimen  in  the  upper  clamp  of  the  testing  machine  first, 
then  carefully  draw  all  of  the  strands  smooth  and  taut,  and  wrap  them  around  a 
second  cardboard  at  the  position  in  which  the  lower  clamp  should  seize  the  strands. 
Caution  should  be  exercised  to  see  that  all  strands  are  parallel,  uniformly  taut,  and 
none  excessively  stretched. 

^  Great  care  should  be  exercised  to  keep  the  roller  smooth,  free  from  rust  or  dirt,  and 
to  see  that  it  is  properly  lubricated  and  adjusted  to  turn  freely  but  with  only  slight 


290 


PHYSICAL  PROPERTIES  OF  SILK 


Section  S.  Sample. — The  sample  for  the  test  shall  consist  of  five  skeins,  and  the 
sampling  of  the  lot  is  as  specified  in  Article  1,  Section  3.  The  test  specimen  consists 
of  fifty  strands  taken  at  intervals  of  not  more  than  two  yards  along  the  thread  from 
a  single  skein  laid  taut  fifty  threads  per  inch  on  a  sheet  of  firm,  unglazed  black  card- 
board to  which  they  are  secm-ed  by  means  of  gummed  paper  tape.  One  test  specimen 
shall  be  prepared  from  each  five  sample  skeins  and  may  be  taken  from  the  bobbins 
of  the  winding  test  or  direct  from  the  sample  skein.  Raw  silk  which  has  been  used 
for  a  conditioned  sizing,  a  serimeter  test,  a  serigraph  test,  or  any  test  which  affects 
its  physical  qualities,  shall  not  be  used  for  the  cohesion  test.  Before  being  used  for 
the  test  the  card  should  be  inspected  to  determine  if  the  threads  have  any  cleanness 

defects  or  pronounced  unevenness  in  the 
portion  which  is  to  be  tested.  Imper- 
fect threads  should  be  removed  before 
starting  the  test  and  in  case  the  strands 
are  noticeably  vmeven  the  card  should 
be  rejected  and  another  card  made. 

Section  4-  Test. — The  sample  cards 
should  be  kept  in  a  standard  atmosphere 
for  at  least  one  hour  after  preparation  to 
insure  that  the  thread  is  in  standard  con- 
dition. The  testing  machine  should  be 
operated  in  a  room  where  the  relative 
humidity  and  temperature  can  be  main- 
tained at  standard  condition  during  the 
test.  The  test  cards  should  be  clamped 
in  the  machine  in  such  a  maimer  as  to 
lie  flat  and  smooth  and  the  threads 
parallel  with  the  direction  of  movement 
of  the  carriage.  The  machine  should 
run  at  a  uniform  speed  of  120  strokes 
per  minute,  and  there  should  be  no  evi- 
dence of  jumping  or  jerking  at  the  end 
of  the  stroke.  As  the  test  proceeds,  the 
threads  should  be  inspected  occasionally. 
As  they  begin  to  open,  frequent  exami- 
nations, at  least  every  fifty  strokes, 
should  be  made  to  determine  when  all 
are  completely  open.i 

Section  5.  Record. — The  record  of  the 
test  should  show  the  number  of  cards 
tested,  the  number  of  strokes  necessary  to  open  all  of  the  threads  on  each  card,  and  the 
average  number  of  strokes. ^ 

endwise  motion.  When  not  in  use,  the  roller  should  be  covered  with  a  film  of  vaseline 
or  oil  to  prevent  rusting,  but  the  film  must  be  thorough^  removed  with  alcohol  or  gaso- 
line before  beginning  a  test. 

1  The  openness  of  the  thread  can  be  conveniently  determined  by  removing  the 
card  from  the  machine,  inserting  a  thin  piece  of  metal  between  the  thread  and  the 
card  and  slightly  raising  the  thread  off  the  card. 

2  In  cases  where  the  threads  do  not  appear  to  be  opening  uniformly  and  a  small 
number  (five  or  less)  indicate  that  they  will  require  a  much  larger  number  of  strokes  to 
open  them,  the  test  may  be  considered  complete  when  90  percent  of  the  threads  are  open. 


Fig.  147. — Seem  Gage  in  Operation  Attached 
to  a  Special  Reehng  Machine. 


CHAPTER  XI 
CHEMICAL  NATURE  AND  PROPERTIES   OF   SILK 

1.  Chemical  Constitution. — The  glands  of  the  sUkworm  appear  to 
secrete  two  transparent  liquids.  The  one;  fibroine,  constituting  from 
one-half  to  two-thirds  of  the  entire  secretion,  forms  the  interior  and 
larger  portion  of  the  silk  fiber;  the  other,  sericine,  also  called  silk-glue, 
forms  the  outer  coating  of  the  fiber.  The  latter  substance  is  yello'w-ish 
in  color,  and  is  readily  soluble  in  boiling  water,  hot  soap,  and  alkaline 
solutions.  As  soon  as  they  are  discharged  into  the  air,  the  fluids  from  the 
spinneret  solidify,  and  coming  into  contact  ■with  each  other  at  the  moment 
of  discharge  are  firml}'  cemented  together  by  the  sericine. 

The  amount  of  sericine  present  in  raw  silk  is  about  23  percent,  and 
this  causes  the  fiber  to  feel  harsh  and  to  be  stiff  and  coarse.  Before  being 
manufactured  into  textiles,  the  raw  silk  is  subjected  to  several  processes 
with  a  \'iew  to  making  it  soft  and  glossy.  The  first  treatment  is  called 
discharging,  stripping,  or  degumming,  and  has  for  its  purpose  the  removal 
of  the  silk-glue.  It  is  really  a  scouring  operation,  the  silk  being  worked 
in  a  soap  solution  at  a  temperatiu-e  of  205°  F.^  In  this  process  thrown 
silk  loses  from  20  to  30  percent  in  weight,  but  becomes  soft  and  glossy. 
AlkaUne  carbonates  are  not  to  be  recommended  for  silk  scouring,  as  they 
are  liable  to  injure  the  fiber,  especially  at  elevated  temperatures.  Soft 
water  should  also  be  employed,  as  lime  makes  the  fiber  brittle. 

Piece-dj'ed  silk  goods,  like  plain  and  figm'ed  pongees,  satins,  and 
similar  fabrics,  are,  as  a  rule,  woven  with  silk  in  the  gum  state,  the  fabrics 
being  afterwards  boiled-off  or  ungimimed.  This,  however,  is  not  possible 
with  fanc}'  colored  fabrics. 

After  several  successive  scourings  the  soap  solution  becomes  hea\'ily 
charged  with  sericine,  and  is  subsequenth'  utilised  in  the  dye-bath  as  an 
assistant,  under  the  name  of  boiled-ofif  liquor. 

According  to  the  report  of  the  conditioning  house  at  Lj-ons  for  the 
year  1908,  the  average  boil-off  losses  for  various  kinds  of  silks  were  as 
f  oUows : 

^  Soap  foam  and  also  certain  mineral  oil  emulsions  are  also  verj'  good  degumming 
agents  for  silk. 

291 


292  CHEMICAL   NATURE   AND   PROPERTIES   OF   SILK 

Yellow  Silks.                    Percent.  White  Silks.                    Percent. 

French 24. 18  French 21 .54 

Italian 23.40  Piedmont 20.68 

Piedmont 22 .  92  Italian 21 .  40 

Spanish 24 .  94  Brusa 21 .  92 

Syrian 24.35  China 17.98 

Bengal 22.09  Canton 22. 17 

Japanese 17 .  90 

Chittick  gives  the  following  boil-off  losses  for  various  kinds  of  raw  silk: 

Percent. 

Japans,  white 18-21 

yellow 21-23 

Italians,  white 20-22 

yellow 20-23 

China,  steam  filature 20-23 

Tsatlees 20-24 

Cantons 20-23 

Tussahs 8-14 

It  may  l^e  said,  therefore,  that  the  boil-off  of  raw  silk  varies  from  18 
to  23  percent,  depending  on  the  origin  of  the  silk.  The  boil-off  loss, 
however,  of  thrown  silk,  which  is  most  generally  the  form  in  which  the 
dyer  and  bleacher  receives  the  silk,  is  usually  considerably  higher  than 
that  of  raw  silk.  It  generally  runs  about  24  to  27  percent,  and  this  is  due 
to  the  fact  that  in  throwing  the  silk  it  is  soaked  in  emulsions  of  oil  and 
soap  in  order  to  soften  up  the  gum,  and  in  this  way  the  fiber  may  absorb 
2  to  5  percent  of  these  ingredients,  which  are,  of  course,  subsequently 
removed  in  the  complete  boil-off. 

According  to  Mulder,  samples  of  yellow  Italian  silk  analysed  as  follows: 

Percent. 

Silk  fiber 53.35 

Matter  soluble  in  water 28 .  86 

"  "        alcohol 1 .  48 

"  "        ether 0.01 

"  "        acetic  acid 16.30 

He  gives  the  chemical  composition  of  the  silk  fiber  as  follows: 

Percent. 

Fibroine 53 .  37 

Gelatine 20.66 

Albumen 24 ,  43 

Wax 1.39 

Coloring  matter 0 .  05 

Resinous  and  fatty  matter 0.10 


CHEMICAL  CONSTITUTION  293 

According  to  Richardson,  mulberry  silk  has  the  following  composition: 

Percent. 

Water 12.50 

Fats 0. 14 

Resins 0 .  56 

Sericine 22.58 

Fibroine 63 .  10 

Mineral  matter , 1 .  12 

Suzuki,  Yoshimura,  and  Inouye  ^  give  the  following  analyses  of  samples 
of  various  Japanese  raw  silks : 


Bombyx 

Mori, 
Percent. 

Sakusan, 
Percent. 

Yama-mai, 
Percent. 

Kuri-wata, 
Percent. 

Moisture 

12.90 
87.10 

13.16 

86.84 

11.29 

88.71 

11  71 

Dry  substance 

88  29 

100  parts  dry  fiber  yielded: 
Ash 

0.63 
99.14 

0.86 
18.98 
18.86 

0.12 

2.92 

92.21 

7.79 

18.87 
16.39 

2.48 

4.73 
97.07 

2.93 
17.73 
17.26 

0.47 

3  85 

Soluble  in  boiling  HCl 

88  34 

Insoluble  in  boiling  HCl 

11  66 

Total  nitrogen 

16  73 

Nitrogen  soluble  in  HCl 

Nitrogen  insoluble  in  HCl.  . 

15.77 
0  96 

100  parts  of  the  total  nitrogen  showed: 
Nitrogen  soluble  in  boiling  HCl .... 

Ammonia  nitrogen 

Nitrogen   ppt.   by   phosphotungstic 
acid 

99.34 
4.57 

1.78 

86.87 
2.52 

13.11 

97.34 
3.85 

19.44 

94.26 
4.08 

15.54 

Chittick  points  out  that  since  the  boil-off  of  Japan  silk  is  lower  than 
that  of  any  other  important  silk,  this  is  of  considerable  advantage  when 
such  silk  is  employed  in  piece  dyeing,  for  the  cloth  will  be  8  to  10  percent 
heavier  than  the  same  character  of  cloth  made  from  yellow  silk;  also  if 
the  silk  is  dyed  in  the  skein  and  weighted  the  amount  of  real  silk  in  the 
thread  will  be  greater  than  with  silks  showing  a  higher  percentage  of 
boil-off.  In  actual  practice  in  the  dyehouse,  the  amount  of  boil-off  will 
usually  be  somewhat  less  than  that  which  may  actually  be  found  in  the 

^Jour.  Coll.  Agric.  Imp.,  Univ.  Tokio,  1909,  p.  59. 


294 


CHEMICAL  NATURE  AND  PROPERTIES  OF  SILK 


laboratory  by  a  complete  boil-off  test,  for  in  the  dyehouse  too  severe  a 
treatment  in  the  boil-off  is  to  be  avoided,  as  this  may  cause  the  individual 
filaments  of  the  fiber  to  be  opened  up,  and  the  dyed  silk  may  be  soft, 
spongy,  and  hairy.  Severe  treatment  in  the  boil-off  may  also  cause  "  lousi- 
ness "  in  the  fiber,  a  condition  due  to  the  splitting  of  the  individual  cocoon 
filaments  into  minute  fibrillae. 

According  to  Chittick  the  percentage  of  weighting  in  skein-dyed  silk 
will  vary  considerably  with  the  boil-off,  consequently  the  boil-off  factor 
becomes  an  important  consideration  in  the  treatment  of  silk,  for  it  will  be 
seen  that  the  ounces  of  weighting  that  may  be  ordered  from  the  dyer  will 
form  no  guide  as  to  the  figure  representing  the  actual  amount  of  weighting 
unless  the  boiled-off  conditioned  weight  of  the  thrown  silk  is  known.  It  is 
obvious,  therefore,  that  the  only  manner  of  calculating  the  exact  degree 
of  weighting  is  to  ascertain  the  conditioned  boiled-off  weight  of  the  thrown 
silk  sent  to  the  dyer  and  then  to  order  on  that  basis  whatever  percentage 
of  weighting  is  desired.  Chittick  gives  the  following  table  showing  the 
actual  percentage  of  weighting  according  to  the  variations  in  the 
boil-offs: 


Weight- 
ing 
Ordered 
Ozs. 

Weight 
Returned 

by 

Dyer. 

Lbs. 

14 

0.875 

16 

1.000 

18 

1.125 

20 

1.250 

22 

1.375 

24 

1.500 

26 

1.625 

28 

1.750 

30 

1.875 

32 

2.000 

36 

2.250 

40 

2.500 

44 

2.750 

48 

3.000 

52 

3.250 

56 

3.500 

60 

3.750 

Boil-offs,  Percentage. 


20 


21 

22 

23 

24 

25 

26 

27 

28 

29 

30 


Actual  Weighting,  Percentage  (on  Boiled-off  Weighting) 


9 

11 

12 

14 

15 

17 

18 

20 

22 

23 

25 

27 

28 

30 

32 

33 

35 

37 

39 

41 

41 

42 

44 

46 

48 

50 

52 

54 

56 

58 

56 

58 

60 

62 

64 

67 

69 

71 

74 

76 

72 

74 

76 

79 

81 

83 

86 

88 

91 

94 

88 

90 

92 

95 

97 

100 

103 

105 

108 

111 

103 

106 

108 

111 

114 

117 

120 

123 

126 

129 

119 

122 

124 

127 

130 

133 

136 

140 

143 

146 

134 

137 

140 

144 

147 

150 

153 

157 

160 

1&4 

150 

153 

156 

160 

163 

167 

170 

174 

178 

182 

181 

185 

188 

192 

196 

200 

204 

208 

213 

217 

213 

216 

221 

225 

229 

2ri3 

238 

242 

247 

252 

244 

248 

253 

257 

262 

267 

272 

277 

282 

287 

275 

280 

285 

290 

295 

300 

305 

311 

317 

323 

306 

311 

317 

322 

328 

333 

339 

345 

351 

358 

338 

343 

349 

355 

361 

367 

373 

379 

386 

393 

369 

375 

381 

387 

393 

400 

407 

414 

421 

428 

25 

43 

61 

79 

96 

114 

132 

150 

168 

186 

221 

257 

293 

329 

364 

400 

436 


CHEMICAL  CONSTITUTION 


295 


Analyses  of  samples  of  mulberry  silk  are  given  by  H.  Silbermann  ^ 
as  follows: 


White. 

Yellow. 

Cocoons, 
Percent. 

Raw, 
Percent. 

Cocoons, 
Percent. 

Raw, 
Percent. 

Fibroine 

Ash  of  fibroine 

73.59 
0.09 

22.28 
3.02 
1.60 

76.20 
0.09 

22.01 
1.36 
0.30 

70.02 
0.16 

24.29 
3.46 
1.92 

72.35 
0  16 

Sericine 

Wax  and  fat 

23.13 
2  75 

Salts 

1.60 

Silbermann  also  gives  a  table  showing  the  difference  in  the  elementary 
composition  between  mulberry  silk  and  tussah  silk: 


Carbon.  . 
Hydrogen 
Nitrogen . 
Oxygen . . 
Ash 


Mulberry  Silk. 


Cocoon 
Threads, 
Percent. 


36.77 

6.21 

17.57 

28.25 
1.20 


Fibroine, 
Percent. 


47.47 

6.37 

17.86 

28.01 

0.29 


Tussah  Silk. 


Cocoon 
Threads, 
Percent. 


46.96 

6.26 

17.60 

26.39 

2.85 


Fibroine, 
Percent. 


48.50 

6.34 

18.37 

26.39 

0.40 


The  amount  of  ash  in  boiled-off  silk  will  vary  somewhat  according  to 
the  origin  of  the  silk,  but  will  average  about  0.50  percent.  In  raw  silk 
the  average  amount  of  ash  will  be  about  1  percent.  In  yama-mai  silk 
the  ash  may  reach  as  high  as  8  percent.  Allen  ^  states  that  the  greater 
part  of  the  mineral  matters  of  raw  silk  are  simply  adherent  to  the  fiber, 
and  are  removed  together  with  the  sericine  by  prolonged  boiling  with 
soap  solution;  the  residual  fibroine  retains  only  about  0.6  percent  of  min- 
eral matter. 

1  Die  Scide,  vol.  2,  p.  210. 

^Commercial  Organic  Analysis,  vol.  4,  p.  507. 


296  CHEMICAL  NATURE  AND  PROPERTIES  OF  SILK 

2.  Fibroine. — This  substance  is  a  proteid  somewhat  analogous  to 
that  contained  in  wool,  and,  like  the  latter,  is  no  doubt  an  amino-acid. 
Mulder  gives  the  analysis  of  fibroine  as  follows: 

Percent. 

Carbon 48.80 

Hydrogen 6 .  23 

Oxygen 25.00 

Nitrogen 19.00 

Vignon  analysed  samples  of  highly  purified  silk,  and  gives  the  following 
figures : 

Percent. 

Carbon 48.3 

Hydrogen 6.5 

Nitrogen 19.2 

Oxygen 26.0 

Vignon  prepares  pure  fibroine  in  the  following  manner:  A  10-gram 
skein  of  raw  white  silk  is  boiled  for  thirty  minutes  in  a  solution  of  15  grams 
of  neutral  soap  in  1500  cc.  water;  rinse  in  hot,  then  in  tepid  water; 
squeeze  and  repeat  the  treatment  in  a  fresh  soap-bath;  rinse  with  water, 
then  with  dilute  hydrochloric  acid,  again  with  water;  finally,  wash  twice 
with  90  percent  alcohol.  The  fibroine  thus  obtained  leaves  only  0.01 
percent  of  ash  on  ignition.^ 

A  mean  of  analyses  by  a  number  of  well-known  investigators  on  the 
composition  of  fibroine  is  as  follows: 

Percent. 

Carbon 48.53 

Hydrogen 6 .  43 

Nitrogen 18 .  33 

Oxygen 26 .  67 

Richardson    suggests    the    following    structural    formula    for    fibroine, 
allowing  x  to  represent  a  hydrocarbon  residue: 

NH— CO 
x<('  J}x. 

The  decomposition  of  fibroine  by  saponification  with  potash  would 
then  be 

NH— CO  NH2 

x<^  \a:-f2KOH=2x/ 

^CO— NH^  ^COOK 

1  Compt.  rend.,  vol.  115.  pp.  17,  613. 


AMOUNT  OF  FIBROINE  IN  RAW  SILK 


297 


3.  Amount  of  Fibroine  in  Raw  Silk. — According  to  Allen  ^  raw  com- 
mercial silk  from  the  mulberry  silkworm  is  generally  regarded  as  containing 
11  percent  of  moisture,  66  percent  of  fibroine,  22  percent  of  sericine,  and 
1  percent  of  mineral  and  coloring  matters. 

The  proportion  of  fibroine  in  raw  silk  has  been  variously  stated  by 
different  observers,  and  appears  to  differ  with  the  method  employed  for 
its  determination.  The  figure  given  by  Mulder  (see  above)  of  53.35 
percent  was  obtained  by  boiling  the  raw  silk  with  acetic  acid.  By  the 
action  of  a  5  percent  solution  of  cold  caustic  soda,  Stadeler  obtained 
42  to  50  percent  of  fibroine.  Cramer  obtained  66  percent  by  heating 
raw  silk  in  water  at  133°  C.  under  pressure.  Francezon  reports  75  percent 
of  fibroine  by  twice  boiling  the  silk  in  a  solution  of  soap  and  then  treating 
with  acetic  acid.  Vignon,  by  carefully  purifying  the  fibroine  by  suitable 
treatment,  obtained  75  percent.  According  to  Fischer  and  Skita^  even 
technically  purified  silk  still  contains  about  5  percent  of  silk-glue. 

In  the  Report  of  the  Milan  Commission  on  Silk  (1906)  it  was  concluded 
that  very  great  differences  existed  in  the  proportion  of  fibroine  given  by 
silks  from  the  same  races  of  Bombyx  mori,  depending  on  conditions  of 
food,  culture,  etc.  Variations  in  the  amount  of  fibroine  from  73  to  84 
percent  have  been  recorded,  and  hence  it  is  impossible  to  base  an  estimate 
of  the  purity  of  silk  upon  the  results  of  such  a  determination.  Owing  to 
the  fact  that  the  amount  of  substances  soluble  in  a  soap  solution  varies 
from  16  to  27  percent,  it  is  obviously  possible  to  add  to  this  amount  by 
artificial  means.  The  permissible  limits  of  impurities  were  determined 
by  the  commission  by  analyses  of  a  large  number  of  samples  of  known 
purity.     From  these  analyses  the  following  table  was  prepared: 


Minimum, 
Percent. 

Maximum, 
Percent. 

Mean, 
Percent. 

Substances  soluble  in  3  percent  soap  solution 

In  distilled  water  at  50°-55°  C 

In  ether 

21.449 
0.447 
0.104 
0.726 

25.913 
1.053 
0.451 
0.903 

22.865 
0.617 
0  275 

Ash 

0  855 

The  amount  of  soluble  gum  in  Japanese  raw  silk  averages  about  18 
percent;  in  China  silk  about  19  percent;  in  yellow  Europeans  about 
22  percent;  and  in  tussah  silk  of  good  quahty  about  15  percent;  while 
low-grade  tussahs  will  lose  much  more. 


^  Commercial  Organic  Analysis,  vol.  4,  p.  506. 

^Zeitschr.  physiol.  Chem.,  vol.  33,  p.  171,  and  vol.  35,  p.  224. 


298  CHEMICAL   NATURE   AND   PROPERTIES  OF  SILK 

4.  Chemical  Properties  of  Fibroine. — Unlike  keratine,  the  proteid 
of  wool,  fibroine  contains  no  sulfur,  and  is  much  more  constant  in  its 
composition.  The  empirical  formula  for  fibroine  as  given  by  Mulder  is 
C15H23N5O6.  Mills  and  Takamine  give  the  formula  as  C24H38N8O8, 
while  Schiitzenberger  gives  C7iHio7N2.i025-  Cramer  arrives  at  the  same 
formula  as  Mulder,  while  Richardson^  gives  C6oH94Ni8025-  Vignon's 
formula  for  specially  purified  fibroine  is  C22H47N10O12. 

Silbermann  found  that  fibroine  heated  with  a  solution  of  barium 
hydrate  under  pressure  was  decomposed  with  the  formation  of  oxalic, 
carbonic,  and  acetic  acids,  together  with  an  amino-body  approximating 
the  formula  C68H141N21O43.  The  latter  compound  is  said  to  undergo 
further  decomposition  with  the  formation  of  tyrosine,  glycocine,  alanine, 
amino-butyric  acid,  and  an  amino-acid  of  the  acrylic  series.  Fischer  and 
Skita  ^  have  shown  that  in  all  probabilit}^  amino-valerianic  acid, 
C3H7-CH(NH)2-COOH,  occurs  in  fibroine.  Silk  fibroine,  however, 
appears  to  differ  from  other  albumens  in  not  containing  aspartic  acid, 
COOH-CH2CH(NH2)-CO-OH.  Glutaminic  acid,  COOH-CH2-CH2- 
CH(NH2) -COOH,  also  appears  to  be  present  in  fibroine,  though  Fischer 
doubts  this. 

The  presence  of  the  amino-group  in  fibroine  has  been  shown,  as  in  the 
case  of  wool,  by  diazotising  the  fiber  with  an  acid  solution  of  sodium  nitrite, 
then  washing  and  treating  with  solutions  of  various  developers,  such  as 
phenol,  resorcinol,  alpha-  and  beta-naphthols,  etc.,  whereby  the  fiber 
becomes  dyed  in  different  colors. 

From  its  action  toward  alcoholic  potash  Richardson  concludes  that 
silk  fibroine  is  probably  an  amino-anhydride  rather  than  an  amino-acid. 
When  boiled  for  a  long  period  with  dilute  sulfuric  acid,  fibroine  is  dis- 
solved to  a  yellowish  brown  liquid,  leaving  as  a  residue  only  a  small  amount 
of  what  is  apparently  a  fatty  acid.  From  this  decomposition  product 
Weyl  succeeded  in  isolating  5.2  percent  of  tyrosine,  7.5  percent  of  glycosine 
and  15  percent  of  a  crystalline  compound  which  was  apparently  alpha- 
alanine. 

Toward  Millon's  and  Adamkiewitz's  reagents  fibroine  gives  the  usual 
reaction  of  proteids,  and  it  also  gives  the  biuret  test. 

Millon's  reagent  consists  of  a  solution  of  mercurous  nitrate  containing 
nitrous  acid  in  solution.  It  is  prepared  by  treating  1  cc.  of  mercury 
with  10  cc.  of  nitric  acid  (sp.  gr.  1.4),  heating  gently  until  complete  solution 
is  effected,  then  diluting  the  solution  with  twice  its  volume  of  cold  water. 
When  a  solution  of  a  proteid  is  treated  with  this  reagent,  a  white  precipitate 
is  first  formed,  which  turns  brick-red  on  boiling;  a  solid  proteid  becomes 
red  when  boiled  with  the  reagent.     Adamkiewitz's  test  is  to  dissolve  the 

^  Jour.  Soc.  Chem.  Ind.,  vol  12,  p.  426. 

^  Zeitschr.f.  physiol.  Chem.,  vol.  33,  p.  177. 


CHEMICAL   PROPERTIES  OF   FIBROINE 


299 


proteid  in  glacial  acetic  acid,  and  then  add  concentrated  sulfuric  acid  to 
the  solution,  when  a  fine  violet  color  will  be  produced,  and  the  liquid 
will  exhibit  a  faint  fluorescence.  The  biuret  test  is  to  add  a  few  drops  of  a 
dilute  solution  of  copper  sulfate  to  the  solution  of  proteid;  then  on  adding 
an  excess  of  caustic  soda  solution  the  precipitate  which  at  first  formed  will 
be  dissolved  with  the  production  of  a  fine  violet  coloration. 

According  to  Richardson,  silk  fibroine  will  absorb  30  percent  of  iodine 
when  treated  with  Hiibl's  reagent.  Attempts  have  been  made  to  acetylise 
fibroine,  but  without  success. 

Cohnheim,  in  his  tables  of  the  percentage  composition  of  variour 
albumens,  gives  the  following  for  the  fibroine  of  silk: 

Percent. 

Glycocoll 36.0 

Alanine 21.0 

Leucine 1.5 

Phenylalanine 1.5 

a-P>Trolidine  carboxylic  acid 0.3 

Serine 1.6 

Tyrosine 10.0 

Arginine 1.0 

The  occurrence  of  the  following  compounds  in  indeterminate  amounts 
is  also  given:  Lysine,  histidine,  tryptophane,  and  amino-valerianic  acid. 

The  following  table  gives  the  products  of  hydrolysis  obtained  from 
various  kinds  of  silk: 


Bombj'x  Mori. 

Raw 

Sakusan, 
Percent. 

Raw 

Yama-mai, 

Percent. 

Raw 

Kuri-wata, 

Percent. 

Raw 

Fibroine, 
Percent. 

Sericine, 
Percent. 

Tussah, 
Percent. 

Glycocoll 

36.0 

21.0 

1.5 

0.3 

12.0 

1.0 
1.05 

0.1-0.2 
5.0 

5.0 

4.0 

1.87 

5.7 
4.8 
1.2 

1.0 
1.4 
2.7 
3.1 
0.6 

6,3 
7.2 
1.3 

0.6 
1.0 
2.0 
1.6 

3.8 
0.8 

7.7 
15.3 
7.95 
4.0 
? 

0.2 
5.5 
1.01 
1.74 
0.8 

35.13 

Alanine 

23  4 

Leucine 

Proline 

Glutaminic  acid 

Asparaginic  acid 

Tyrosine 

Histidine 

1.76 
3.68 
6.16 

4.2 

Arginine 

Ainmonia. 

5.24 
1.16 

Fibroine  is '  insoluble  in  ammonia  and  solutions  of  the  alkaline  car- 
bonates; neither  is  it  dissolved  by  a  1  percent  solution  of  caxistic  soda,  but 


300  CHEMICAL   NATURE   AND   PROPERTIES   OF   SILK 

stronger  solutions  affect  it,  especially  if  hot.  From  its  solution  in  caustic 
soda  fibroine  may  be  reprecipitated  by  dilution  with  water.  Fibroine 
is  also  soluble  in  hot  glacial  acetic  acid,  and  in  strong  hydrochloric,  sulfuric, 
nitric,  and  phosphoric  acids.  Alkaline  solutions  of  the  hydroxides  of 
such  metals  as  nickel,  zinc,  and  copper  also  dissolve  fibroine. 

If  silk  fibroine  is  dissolved  in  cold  concentrated  hydrochloric  acid, 
and  the  solution  be  allowed  to  stand  sixteen  hours  at  the  ordinary  tempera- 
ture with  three  times  its  volume  of  hydrochloric  acid  (sp.  gr.  1.19),  it  will 
no  longer  be  precipitated  by  the  addition  of  alcohol.  The  fibroine  appears 
to  have  suffered  hydrolysis,  being  converted  into  a  body  similar  to  peptone. 
This  substance  may  be  separated  out  by  steaming  the  above  solution  under 
diminished  pressure.  If  its  aqueous  solution  be  neutralised  with  ammonia 
and  some  trypsine  ferment  be  added,  tyrosine  will  begin  to  crystallise  out 
in  a  few  hours. 

Fischer  and  Abderhalden  ^  have  succeeded  in  isolating  from  the  hydro- 
chloric acid  solution  of  silk  fibroine  a  dipeptide  in  the  form  of  methyl- 
diketopiperazine,  having  the  formula 

CH2CO 

nh/  \nh. 

^COCH< 

^CHs 

The  yield  is  about  12  percent,  and  the  product  is  identical  with  that 
obtained  synthetically  from  glycocoU  and  <^/-alanine. 

5.  Sericine. — According  to  the  analysis  of  Richardson,  sericine  has  the 
following  composition: 

Percent. 

Carbon 48. 80 

Hydrogen 6.23 

Oxygen 25.97 

Nitrogen 19.00 

and  its  formula  is  given  as  C16H25N5OS.  It  is  considered  by  some  as  an 
alteration  product  of  fibroine,  strong  hydrochloric  acid  is  said  to  convert 
the  latter  into  sericine,  the  conversion  is  supposed  to  take  place  by  assimila- 
tion of  water  and  oxygen. 

Ci5H23N50g  +  H20  +  0  =  CigH25N508. 
Fibroine.  Sericine. 

Sericine  may  be  obtained  in  a  pure  condition  by  first  boiling  a  sample 
of  raw  silk  in  water  for  several  hours,  after  which  the  sericine  is  pre- 

1  Berichte,  1906,  p.  752. 


SERICINE  301 

cipitated  by  lead  acetate.  Pure  sericine  may  also  be  prepared  by  pre- 
cipitating crude  sericine  solution  with  1  percent  acetic  acid,  washing  the 
separated  sericine  by  repeated  decantation  with  water,  then  treating 
with  cold  and  afterwards  with  boiling  alcohol,  and  finally  extracting  with 
ether.     Pure  sericine  contains 

Percent. 

Carbon 45.00 

Hydrogen 6 .  32 

Nitrogen 17 .  14 

Oxygen 31 .  54 

It  is  easily  soluble  in  water,  In  concentrated  hydrochloric  acid,  and 
in  potassium  carbonate;   sodium  carbonate  only  causes  a  swelling. 

On  treatment  with  dilute  sulfuric  acid,  sericine  yields  a  small  quantity 
of  leucine  and  tyrosine,  but  no  trace  of  glycocoll,  the  principal  product 
formed   being  a   crystalline  body  called  serine,  which  appears  to  have 

NH2 
the  formula  C2Hi<^  ,  and  from  its  chemical  reactions  is  evidently 

^COOH 
analogous  to  glycocine  probably  being  amino-glyceric  acid. 

Sericine  is  soluble  in  hot  water,  hot  soap  solutions,  and  dilute  caustic 
alkalies.  The  aqueous  solution  is  precipitated  by  alcohol,  tannin,  basic 
lead  acetate,  stannous  chloride,  bromine,  and  iodine,  and  bj^  potassium 
ferrocyanide  in  the  presence  of  acetic  acid.  By  treatment  with  formalde- 
hyde, it  is  claimed  that  sericine  is  rendered  insoluble  in  both  hot  water 
and  soap  solutions;  consequently,  raw  silk  may  be  treated  with  this 
reagent  for  use  in  certain  applications  where  it  may  be  desired  to  retain 
as  far  as  possible  the  coating  of  silk-glue. 

Mulder  gives  the  formula  of  C15H25N5O8  to  sericine  and  the  following 
composition : 

Percent. 

Carbon 42.60 

Hydrogen 5 .  90 

Oxygen 35.00 

Nitrogen 16.50 

According  to  Bolley,  the  composition  of  sericine  is 

Percent. 

Carbon "4 .  32 

Hydrogen 6.18 

Oxygen 31 .  20 

Nitrogen 18.30 


302  CHEMICAL   NATURE   AND   PROPERTIES   OF   SILK 

According  to  the  tables  of  Cohnheim,  the  percentages  of  known  con- 
stituents in  silk-glue  are  as  follows : 

Percent. 

GlycocoU 0.1-0.2 

Alanine 5 

Leucine Not  determined 

Serine 6.6 

Tyrosine 5 

Lysine Not  determined 

Arginine 4 

Ammonia 1 .  87 

Vignon,^  by  observing  the  action  of  solutions  of  sericine  and  fibroine 
on  polarised  light,  found  that  both  of  these  constituents  of  silk  were 
laevogyrate,  and  their  rotatory  powers  were  about  equal,  approximating 
to  40°.  This  is  in  keeping  with  observations  made  on  other  albumi- 
noids. 

6.  Coloring  Matter. — According  to  Dubois  the  yellow  coloring  matter 
of  silk  is  similar  to  carotin.  He  obtained  five  different  bodies  from  the 
natural  coloring  matter  of  silk,  as  follows:  (1)  A  golden-yellow  coloring 
matter,  soluble  in  potassium  carbonate  and  precipitated  by  acetic  acid; 
(2)  crystals  which  appear  yellowish  red  by  transmitted  light  and  brown 
by  reflected  light;  (3)  a  lemon-colored  amorphous  body,  the  alcoholic 
solution  of  which  on  evaporation  gave  granular  masses;  (4)  yellow 
octahedral  crystals  resembling  sulfur;  (5)  a  dark  bluish  green  pigment  in 
minute  quantities  and  probably  crystalline. 

Levrat  and  Conte  ^  have  shown  that  the  color  of  natural  silk  is  due  to 
the  coloring  matter  present  in  the  leaves  on  which  the  silkworms  feed; 
chlorophyl  being  the  coloring  matter  in  the  case  of  green  silks,  while 
yellow  silks  contain  the  yellow  coloring  matter  of  the  mulberry  leaves. 
These  investigators  made  experiments  by  feeding  silkworms  with  leaves 
stained  with  various  artificial  dyes,  and  it  was  found  that  the  silk  produced 
was  more  or  less  colored.  The  silk  from  the  Atlacus  orizaba  give  a  more 
pronounced  color  than  that  from  the  ordinary  silkworm. 

7.  Chemical  Reactions:  Heat. — In  its  general  chemical  behavior  silk 
is  quite  similar  to  wool.  It  will  stand  a  higher  temperature,  however, 
than  the  wool  fiber,  without  receiving  injury;  it  can  be  heated,  for  instance, 
to  110°  C.  without  danger  of  decomposition;  at  170°  C,  however,  it  is 
rapidly  disintegrated.  On  burning  it  liberates  an  empyreumatic  odor 
which  is  not  as  disagreeable  as  that  obtained  from  burning  wool. 

8.  Action  of  Water. — Silk  is  a  highly  absorbent  fiber  and  readily  becomes 
impregnated  or  wetted  by  water.     Dissolved  substances  present  in  the 

1  Compt.  rend.,  vol.  103,  p.  802. 

2  Jour.  Soc.  Chem.  Ind.,  vol.  2,  p   172. 


ACTION  OF  ACIDS  303 

water  also  are  rather  readih^  absorbed  or  taken  up  by  the  silk;  therefore, 
it  is  easy  to  understand  that  hard  and  impure  waters  are  sources  of  con- 
tamination for  silk  goods  with  which  these  waters  come  in  contact  during 
processes  of  washing,  dyeing,  or  finishing.  The  softness  and  luster  of  the 
fiber  is  quite  easily  afiected  by  these  impurities;  consequently  it  is  to  be 
recommended  that  wherever  water  is  employed  in  connection  with  silk 
that  the  water  be  as  soft  as  possible.  So  thoroughly  is  this  fact  realised 
at  the  present  time  that  most  modern  silk  factories  use  water  softened 
by  the  zeohte  process  whereby  the  hardness  may  be  reduced  practically 
to  zero.  The  character  of  the  water  employed  in  reehng  silk  from  the 
cocoons  is  also  said  to  have  considerable  influence  on  the  quality  of  the  silk 
produced.  The  best  results  are  obtained  when  as  soft  a  water  as  possible 
is  used. 

9.  Action  of  Acids. — Silk  readily  absorbs  dilute  acids  from  solutions, 
and  in  so  doing  increases  in  luster  and  acquires  the  scroop  of  which  mention 
has  previously  been  made.  Unlike  wool,  it  has  a  strong  affinity  for 
tannic  acid,  which  fact  is  utilised  for  both  weighting  and  mordanting  the 
fiber. 

The  reaction  betw^een  silk  and  tannic  acid  is  different  from  that  with 
other  textile  fibers.  Heermann  ^  points  out  that  vegetable  fibers  absorb  only 
small  amounts  of  tannic  acid,  a  state  of  equilibrium  being  produced  which 
depends  on  the  relative  amounts  of  water,  tannic  acid,  and  fiber.  The 
tannic  acid  absorbed  by  vegetable  fibers  is  also  readily  removed  by  cold 
water.-  Wool  absorbs  but  little  tannic  from  cold  solutions,  and  when 
treated  with  hot  solutions  the  fiber  becomes  harsh.  The  silk  fiber,  however, 
behaves  somewhat  like  hide  in  that  it  absorbs  a  large  amount  of  tannic 
acid  from  cold  solutions,  and  as  much  as  25  percent  of  its  weight  from  a  hot 
solution.  Furthermore,  the  tannin  absorbed  by  silk  is  not  readily  remove  ti 
by  treatment  with  water.  Heermann  experimented  on  the  absorption  of 
various  tannins  by  silk,  the  foUowdng  tannins  being  employed:  Gambicr, 
gambler  substitute,  Aleppo  gall  extract,  sumac  extract,  and  divi-divi 
extract;  the  samples  of  silk  used  for  the  pm-pose  being  (1)  pure  silk  whicli 
had  been  degmnmed,  (2)  silk  dyed  wth  Prussian  blue,  and  (3)  silk  moi- 
danted  with  tin  chloride  and  sodium  phosphate.  The  following  conclusions 
were  deduced :  jMost  tannin  is  absorbed  by  all  three  samples  of  silk  from 
the  gambler  extract;  pure  silk  absorbs  almost  as  much  from  gall  extract 
and  from  sumac  extract,  but  the  prepared  samples  of  silk  showed  only  a 
slight  absorption  of  these  two  tannins.  Divi-divi  comes  next  to  gambler 
in  amount  of  absorption.  Gambler  substitute  is  peculiar,  as  tannin  is 
absorbed  from  it  only  when  the  solutions  are  concentrated. 

1  Farb.  Zeit.,  1908,  p.  4. 

-See  Knecht  and  Kershaw,  Jour.  Soc.  Chem.  Ind.,  1892,  p.  129;  also  Georgievics, 
MUt.  des  tech.  Gewerbe  Museums  in  Wien,  1898,  p.  362. 


304  CHEMICAL  NATURE  AND  PROPERTIES  OF  SILK 

Concentrated  sulfuric  and  hydrochloric  acids  dissolve  silk;  nitric 
acid  colors  silk  yellow,  as  in  the  case  with  wool,  probably  due  to  the  forma- 
tion of  xanthoproteic  acid.  This  color  can  be  removed  by  treatment 
with  a  boiling  solution  of  stannous  chloride.  The  action  of  nitric  acid 
on  silk  is  rather  a  peculiar  one.  When  treated  for  one  minute  with  nitric 
acid  of  sp.  gr.  1.33  at  a  temperature  of  45°  C,  the  silk  acquires  a  yellow 
color  which  cannot  be  washed  out  and  is  also  fast  to  light.  Pure  nitric 
acid  free  from  nitrous  compounds,  however,  does  not  give  this  color.  On 
treating  the  yellow  nitro-silk  with  an  alkali,  the  color  is  considerably 
deepened.  Vignon  and  Sisley  ^  found  that  the  purified  fibroine  of  silk 
when  treated  with  nitrous  nitric  acid  increased  2  percent  in  weight. 

With  strong  sulfuric  acid  nitro-silk  swells  up  and  gives  a  gelatinous 
mass  resembling  egg  albumen.  The  solubility  of  silk  in  strong  hydro- 
chloric acid  is  very  rapid,  a  minute  or  two  sufficing  for  complete  solution. 
Under  such  conditions  wool  and  cotton  fibers  are  but  slightly  affected, 
hence  such  a  treatment  may  be  used  for  the  separation  of  silk  from  wool 
or  cotton  for  the  purpose  of  analysis.  Though  silk  is  soluble  in  concen- 
trated acids  if  their  action  is  continued  for  any  length  of  time,  it  appears 
that  if  silk  be  treated  with  concentrated  sulfuric  acid  for  only  a  few  min- 
utes, then  rinsed  and  neutralised,  the  fiber  will  contract  from  30  to  50 
percent  in  length  without  otherwise  suffering  serious  injury  beyond  a 
considerable  loss  in  luster.  This  action  of  concentrated  acids  on  silk  has 
been  utilised  for  the  creping  of  silk  fabrics,  the  acid  being  allowed  to  act 
only  on  certain  parts  of  the  material.  It  appears  that  tussah  silk  is  not 
affected  by  the  acid  to  the  same  degree  as  ordinary  silk,  and  hence  creping 
may  be  accomplished  by  mixing  tussah  with  ordinary  silk,  and  treating 
the  entire  fabric  with  concentrated  acid. 

HydrofluosiUcic  acid  and  hydrofluoric  acid  in  the  cold  and  in  5  percent 
solutions  do  not  appear  to  exert  any  injurious  action  on  the  silk  fiber; 
these  acids,  however,  remove  all  inorganic  weighting  materials,  and  their 
use  has  been  suggested  for  the  restoring  of  excessively  weighted  silks  to 
their  normal  condition,  so  that  they  may  be  less  harsh  and  brittle. 

According  to  Farrell  -  when  silk  is  treated  with  hydrochloric  acid  of  a 
density  of  29°  Tw.  it  shrinks  about  one-third  without  any  appreciable 
deterioration  in  the  strength  of  the  fiber.  With  solutions  of  acid  below 
29°  Tw.  no  contraction  occurs,  while  with  solutions  above  30°  Tw.  com- 
plete disintegration  of  the  fiber  results.  In  the  production  of  crepon 
effects  by  this  method,  the  fabric  is  printed  with  a  wax  resist,  and  is  then 
immersed  in  the  hydrochloric  acid;  the  contraction  is  complete  in  one  to 
two  minutes,  after  which  the  fabric  is  well  washed  in  water.  Nitric  acid 
and  ortho-phosphoric  acid  may  also  be  employed  for  the  creping  of  silk 

^  Compt.  rend.,  189L 

2  Jour.  Soc.  Dyers  &  Col,  1905,  p.  70. 


ACTION  OF  ALKALIES  305 

fabrics.*  According  to  a  French  patent  a  similar  effect  may  be  obtained 
by  treating  silk  with  a  solution  of  zinc  chloride  of  from  32°  to  76°  Tw.^ 

When  silk  is  treated  at  ordinary  temperatures,  with  90  percent  formic 
acid,  the  silk  swells  and  contracts  and  becomes  gelatinous,  and  can  be 
drawn  out  into  threads  which,  however,  have  not  much  strength.  The 
action  is  complete  in  two  or  three  minutes.  If  the  acid  is  then  drained 
off  and  the  silk  is  thrown  into  water,  the  rinsing  restores  it  nearly  to  its 
original  condition  with  sufficient  elasticity  to  enable  it  to  be  stretched 
to  its  original  length  with  the  hands.  On  drying  silk  so  treated,  it  becomes 
stiff er  and  generally  more  lustrous,  without  any  loss  of  tensile  strength. 
The  original  shrinking  varies  from  8  to  12  percent  of  the  length  before 
treatment.  Formic  acid  has  the  same  action  on  natural  silks,  whether 
degummed  or  not;  but  chappe  silk,  which  is  not  very  strong  to  begin 
with,  may  lose  somewhat  in  strength.  The  treatment  has  very  little 
effect  on  tussah.  The  best  results  are  obtained  with  grege,  whether 
degummed  or  not,  treating  with  90  percent  formic  acid  for  five  minutes, 
and  then  rinsing  thoroughly.  The  degumming  may  then  follow  with  20 
percent  of  olive  oil  soap  in  the  usual  way.  The  hank  shortens  by  8  to  12 
percent  and  loses  weight  in  the  same  proportion  on  the  average,  but  the 
loss  of  weight  depends  on  the  quality  of  the  original  silk.  This  contraction 
of  the  fiber,  so  similar  to  that  of  cotton  under  the  influence  of  caustic  soda, 
has  given  rise  to  many  attempts  to  enhance  the  luster  of  the  silk  itself  by 
treating  it  exactly  on  Lowe's  lines,  using,  of  course,  formic  acid  instead  of 
caustic  soda.  These  attempts  have  met  with  a  certain  amount  of  success 
for  bringing  up  the  luster  of  inferior  silks,  but  the  tendering  of  the  fiber 
is  often  considerable,  and  the  new  luster  is  not  altogether  agreeable  to  the 
eye.  The  tendering  is  also  associated  with  fraying  of  the  fiber  and  also 
with  the  formation  of  lumps  caused  by  the  cohesion  of  the  frayed  parts. 
On  treating  half-silk  (silk  and  cotton)  with  formic  acid,  the  fabric  is 
creped  by  the  shrinking,  without  the  injury  to  the  silk  that  would  result 
from  the  use  of  caustic  soda,  but  the  process  is  expensive. 

10.  Action  of  Alkalies. — Silk  is  not  as  sensitive  to  dilute  alkalies  as 
wool,  though  the  luster  of  the  fiber  is  somewhat  diminished.  It  is  said 
that  when  mixed  with  glucose  or  glycerol  caustic  soda  does  not  dissolve 
the  silk  fiber  to  any  extent,  but  only  removes  the  gum.  When  treated 
with  strong  hot  caustic  alkalies  the  silk  fiber  dissolves.  Ammonia  and 
soaps  have  no  effect  on  silk  beyond  dissolving  the  silk-glue  or  sericine; 
though  on  long-continued  boiling  in  soap,  the  fibroine  is  also  attacked. 
Borax  has  no  injurious  action  on  silk,  but  neither  has  it  any  special  solvent 
action  on  silk-glue,  hence  it  is  not  serviceable  as  a  stripping  agent.  If 
raw  silk  is  steeped  in  lime-water,  the  fiber  will  swell  to  some  extent  and 

>  See  C.  and  P.  DepouUy,  Jour.  Soc.  Dyers  &  Col,  1896,  p.  8. 
-  Jour.  Soc.  Dyers  &  Col,  1899,  p.  214. 


306  CHEMICAL  NATURE  AND  PROPERTIES  OF  SILK 

the  silk-glue  will  become  somewhat  softened.  If  the  action  of  the  lime- 
water  is  continued,  however,  the  silk  will  become  brittle. 

11.  Action  of  Metallic  Salts,  etc, — Toward  the  ordinary  metallic  salts 
used  as  mordants  silk  exhibits  quite  an  affinity;  in  fact,  to  such  an  extent 
can  it  absorb  and  fix  certain  metallic  salts  that  silk  material  is  frequently 
heavily  mordanted  with  such  salts  for  the  purpose  of  unscrupulously 
increasing  its  weight. 

The  tensile  strength  of  weighted  silk  is  often  less  than  that  of  the  pure 
silk;  and  furthermore,  the  weighting  materials  sometimes  causes  a  rather 
rapid  deterioration  of  the  fiber.  Strehlenert  ^  has  shown  that  the  strength 
of  black  dyed  silk  weighed  to  140  percent  was  less  than  one-sixth  that  of 
the  pure  raw  silk.  White  and  colored  silks  are  usually  weighted  with  tin 
phosphate  and  silicate,  and  this  may  cause  the  fiber  gradually  to  become 
brittle  and  to  disintegrate.  Reddish  spots  frequently  develop  on  such 
weighted  silk,  probably  resulting  from  the  action  of  salt  contained  in  the 
perspiration  from  the  workman  handling  the  material.  By  treating  tin 
weighted  silk  wath  preparations  containing  ammonium  sulfocyanide, 
glycerol,  and  tannin,  the  rapid  deterioration  of  the  silk  may  be  largely 
prevented.  Sunlight  seems  to  accelerate  the  destructive  action  of  tin 
weighting,  though  according  to  Silbermann  this  effect  is  much  reduced 
if  stannous  salts  are  absent.  Gianoli  ^  states  that  this  reactivity  of  the 
tender  silk  is  not  due  to  the  presence  of  stannous  salts,  but  rather  to 
decomposition  products  of  the  silk,  resulting  from  the  effects  of  oxidation 
and  hydrolj^sis  upon  the  silk  fibroine.  These  decomposition  products  are 
soluble  in  water  and  include  ammonia  and  other  nitrogenous  compounds. 
When  exposed  to  sunlight  in  a  vacuum  or  in  an  atmosphere  of  an  inert 
gas,  the  fiber  does  not  become  tender,  but  is  seriously  affected  when  the 
exposure  is  carried  out  in  the  presence  of  air  or  moisture.  In  this  connec- 
tion Silbermann  recommends  the  following  test  to  detect  the  presence  of 
the  stannous  compound.  The  sample  of  silk  is  heated  with  an  acidified 
solution  of  mercuric  chloride;  if  tin  in  the  stannous  condition  is  present, 
mercurous  chloride  will  be  deposited  on  the  fiber  and  will  yield  a  dark  gray 
sulfide  when  treated  with  hydrogen  sulfide.  Silbermann  also  concludes 
that  the  presence  of  ferrous  salts  in  the  iron  mordants  used  for  black  dyed 
silk  has  a  similar  destructive  action  on  the  fiber. 

Treatment  of  weighted  silk  (tin-silico-phosphate  method)  with  thiourea 
and  with  hydrosulfite-formaldehyde  compounds  also  decreases  the  tender- 
ing action  of  the  weighting  material,  and  such  processes  are  now  in  com- 
mercial use. 

Hydroquinone  sulfonate  is  also  employed  to  prevent  the  deterioration 
of  weighted  silk.     The  amount  required  is  from  |  to  5  percent  of  sodium 

1  Che?7i.  Zeit.,  1901,  p.  400. 

2  Chem.  Zeit.,  1910,  p.  105. 


ACTION   OF  METALLIC   SALTS 


307 


salt  of  hydroquinone  sulfonate  and  is  applied  in  solution  as  an  after- 
treatment  to  the  weighted  silk.  Ammonium  sulfocyanide  is  usually 
employed  directly  in  the  tin  bath  itself,  from  ^  to  3  percent  of  the  salt 
being  used. 

Solutions  of  sodium  chloride  appear  to  have  a  peculiar  action  on  the 
silk  fiber,  especially  in  the  presence  of  weighting  materials.  According 
to  the  researches  of  Sisley,  solutions  of  common  salt  acting  on  weighted 
silk  in  the  presence  of  air  and  moisture  cause  a  complete  destruction 
of  the  fiber  in  twelve  months,  if  charged  with  but  0.5  percent  of  salt; 
1  percent  of  salt  causes  a  very  pronounced  tendering  of  the  fiber  in  two 
months,  while  2  to  5 
percent  of  salt  causes 
a  distinct  tendering 
in  seven  days.  The 
action  of  the  salt  is 
shared  in  a  lesser  de- 
gree by  the  chlorides 
of  potassium,  am- 
monium, magnesium, 
calcium,  barium, 
aluminium,  and  zinc, 
and  is  probably  due 
to  chemical  dissocia- 
tion. This  fact  may 
account  for  the  stains 
sometimes  found  in 
skeins  of  silk  which 
also  show  a  tendering 
of  the  fiber.  These 
stains  have  frequent- 
ly been  noticed,  and  thorough  investigation  has  failed  to  satisfactorily 
account  for  them.  The  salt  may  get  into  the  fiber  through  the  perspiration 
of  the  workmen  handling  the  goods,  or  through  a  variety  of  other  causes. 

A  concentrated  solution  of  basic  zinc  chloride  readily  dissolves  the 
silk  fiber.  On  diluting  this  solution  with  water  a  flocculent  precipitate 
is  obtained  which  is  soluble  in  ammonia,  and  the  latter  solution  has  been 
employed  for  coating  vegetable  fibers  with  silk  for  the  production  of 
certain  so-called  "  artificial  silks."  An  acid  solution  of  zinc  chloride  acts 
in  the  same  manner.  Solutions  of  copper  oxide  or  nickel  oxide  in  ammonia 
also  act  as  solvents  toward  silk.  The  latter  solution  can  be  employed  for 
separating  silk  from  cotton,  the  silk  being  readily  and  completely  soluble 
in  a  boiling  solution  of  ammoniacal  nickel  oxide,  whereas  cotton  loses  less 
than  1  per  cent  of  its  weight.     A  boiling  solution  of  basic  zinc  chloride 


Fig    148  —Raw  Silk  in  Schweitzer's  Reagent.     ( X 100.) 
(After  Herzog.) 


308  CHEMICAL  NATURE  AND  PROPERTIES  OF  SILK 

(1:1)  will  dissolve  silk  in  one  minute,  while  cotton  under  the  same  treat- 
ment loses  only  0.5  percent,  and  wool  only  1.5  to  2  percent.  Silk  is  also 
soluble  in  Schweitzer's  reagent  (ammoniacal  copper  oxide),  and  in  an 
alkaline  solution  of  copper  sulfate  and  glycerol.  The  latter  is  used  to 
separate  silk  from  wool  and  cotton;  and  the  following  solution  is  recom- 
mended: 16  grams  copper  sulfate,  10  grams  glycerol,  and  150  cc.  of  water. 
After  dissolving,  add  a  solution  of  caustic  soda,  until  the  precipitate 
which  at  first  forms  is  just  redissolved.  Chlorine  destroys  silk,  as  do  other 
oxidising  agents,  unless  employed  in  very  dilute  solutions  and  with  great 
care.  Strong  solutions  of  stannic  chloride  (70°  Tw.)  will  dissolve  silk,  an 
action  which  should  be  borne  in  mind  when  mordanting  and  weighting  silk 
with  this  salt.  Silk  also  absorbs  sugar  to  a  considerable  degree,  and 
this  substance  may  be  employed  as  a  weighting  material  for  light-colored 
silks  on  this  account. 

12.  Action  of  Dyestuffs. — Toward  coloring  matters  in  general,  silk 
exhibits  a  greater  capacity  of  absorption  than  perhaps  any  other  fiber. 
It  also  absorbs  dyestuffs  at  much  lower  temperatures  than  does  wool. 

As  silk  is  evidently  an  amino-acid,  it  possesses  distinct  chemical 
characteristics;  that  is  to  say,  it  exhibits  both  acid  and  basic  properties 
in  a  manner  similar  to  wool.  Like  the  latter  fiber  it  is  probable  that  the 
active  chemical  groups  in  silk  have  considerable  influence  on  its  dyeing 
properties,  especially  with  reference  to  acid  and  basic  dyes,  for  it  has 
been  shown  that  if  these  active  molecular  groups  are  rendered  inactive 
by  acetylation  or  otherwise,  the  dyeing  properties  of  the  silk  are  accordingly 
altered. 

Sansone  ^  states  that  if  silk  is  treated  cold  for  two  or  three  minutes 
with  90  percent  formic  acid  solution  it  rapidly  swells,  softens,  and  becomes 
viscous.  From  comparative  dye  tests  it  would  seem  that  the  treated 
silk  has  a  greater  affinity  for  substantive  dyestuffs  and  for  metallic  mor- 
dants. This  result  was  confirmed  with  treated  silk  which  had  been  sub- 
sequently neutralised  with  sodium  carbonate  solutions,  thus  proving  that 
the  increased  affinity  is  not  caused  by  free  formic  acid  remaining  in  the 
fiber,  but  by  change  in  the  physical  nature  of  the  silk  itself.  With  basic 
and  acid  dyes  the  increase  in  affinity  is  much  less  marked.  Many  artificial 
silks,  and  more  especially  viscose  silk,  show  a  similar  change  in  dyeing 
properties  after  a  formic  acid  treatment  but  an  immersion  of  several  hours 
is  necessary  to  produce  the  effect. 

13.  Weighting  of  Silk. — The  discovery  of  tin  weighting  marks  a  turning 
point  in  the  development  of  the  silk  industry.  The  secrecy  in  which  the 
process  was  originally  shrouded  prevented  the  name  of  its  discoverer 
from  being  handed  down,  just  as  was  the  case  later  with  the  fixing  of  tin 
with  phosphoric  acid,  and  with  the  silicate  method  of  weighting.     Several 

1  Rev.  Gen.  Mat.  Col,  1911,  p.  194. 


WEIGHTING  OF  SILK  309 

points  come  into  consideration  in  discussing  the  effects  of  tin  weighting, 
and  these  are: 

(1)  Of  all  metallic  salts,  those  which  have  the  greatest  affinity  for  silk  are  the 
salts  of  tin. 

(2)  This  affinity  enables  the  fiber  to  assimilate  enormous  quantities  Oii  repeated 
weighting. 

(3)  Any  tin  load  on  the  silk  wUl  serve  as  a  foundation  for  other  weightings  which 
the  silk  could  not  otherwise  take  up. 

(4)  Tin  weighting  has  no  effect  upon  the  color  of  the  fiber,  and  permits  it  to  be 
dyed  any  conceivable  hue. 

(5)  A  tin  loading  properly  used,  and  reasonable  in  amount,  has  a  most  beneficial 
effect  both  upon  the  luster  and  on  the  handle  of  the  silk,  and  does  but  little  injury 
to  its  strength,  elasticity,  or  durability. 

While  most  metaUic  compounds  suitable  for  silk-weighting  are  taken 
up  by  the  fiber  to  the  extent  of  a  few  percent  at  most,  some  of  them  less 
than  1  percent,  silk  takes  up  on  the  average  from  8  to  10  percent  of  its 
weight  of  oxide  of  tin  from  a  suitable  tin  solution.  In  weighting  silk 
with  tin  and  sodium  phosphate,  for  each  2  ozs.  of  weighting  the  silk  must 
be  given  one  pass  through  the  tin  bath.  The  discovery  of  these  high 
figures  of  tin  caused  the  trial  of  nearly  every  other  metal  for  silk-weighting. 
Those  of  high  atomic  weight,  especially  lead,  gave  good  results,  which 
seemed  very  promising,  especially  as  lead  is  so  much  cheaper  than  tin. 
All  these  expectations,  however,  were  doomed  to  disappointment,  and  not 
even  the  great  increase  in  the  cost  of  tin,  even  prior  to  the  war,  was  able  to 
check  the  development  of  it  suse  for  silk-weighting.  It  was  already  known 
that  repeated  metallic  baths  gave  an  increased  weighting,  with  tannin 
the  silk  became  quickly  saturated,  and  therefore  unsusceptible  to  any 
further  action.  As  many  as  ten,  or  even  fifteen,  iron  baths  were  not 
uncommonly  given,  and  if  the  fixed  oxide  of  iron  is  converted  into  Prussian 
Blue  the  silk  will  then  take  up  still  more  of  the  metal.  Although  chromium 
weighting  can  be  increased  by  repeated  baths,  there  is  no  action  with 
ferrocyanide  analogous  to  that  which  forms  Prussian  Blue  in  the  case  of 
iron,  and  chromium  salts  are  dearer  than  iron  salts  as  well.  Hence  they 
are  not  used  on  silks  except  as  mordants  for  dyes.  Alumina  is  taken  up 
by  silk  to  a  small  extent  only,  and  the  amount  is  not  increased  by  repeating 
the  bath. 

The  degree  of  weighting  in  silks  varies  with  the  character  of  the  goods. 
For  cheap  black  fabrics,  heavy  ribbed  or  gros  grains,  where  the  filling  is 
entirely  covered,  weighting  up  to  49  ozs.  is  used  for  the  filling  yarns. 
For  black  goods  of  fair  quality,  the  warp  may  be  weighted  to  20  to  26  ozs. 
and  the  filling  26  to  30  ozs.  For  colored  goods  with  tin  weighting  it  is  not 
safe  to  go  above  18  ozs.  for  the  warp  and  24  ozs.  for  the  filling.  According  to 
Chittick,  the  limits  of  judicious  weighting  are  16  ozs.  for  organzine  and  22 
ozs,  for  tram.     Above  these  limits  the  silk  is  liable  to  deteriorate  too  soon. 


310  CHEMICAL  NATURE  AND  PROPERTIES  OF  SILK 

Treatment  with  sodium  phosphate  after  the  tin  bath  was  a  great 
advance  in  the  art  of  silk-weighting.  Before  its  time  the  tin  was  fixed 
in  soda,  ammonia,  or  some  other  alkah.  Although  the  rinsing  after  the 
tin  bath  does  most  of  the  fixing,  the  alkali  is  necessary  to  remove  the 
traces  of  acid  left  in  the  silk.  This  residual  acid,  although  it  only  amounts 
to  from  1.14  to  1.7  percent,  praeticalh'  prevents  any  fm'ther  weighting  in 
a  fresh  bath.  After  neutralisation,  the  fiber,  which  itself  acts  as  a  weak 
alkali,  can  take  up  a  fresh  lot  of  tin.  Now  the  hydrated  oxide  of  tin  which 
is  precipitated  on  the  fiber  is  a  free  base,  and  injures  the  silk  considerably 
on  exposure  to  air  and  light.  If,  however,  the  oxide  is  neutralised  by 
combination  with  phosphoric  acid,  not  only  are  the  durability  and  strength 
of  the  silk  increased  instead  of  being  diminished,  but  the  expense  of  the 
weighting  is  made  less.  Other  acids  have  been  tried,  but  none  answers 
so  well  as  phosphoric.  Boric  acid  proved  absolutely  useless,  and  although 
some  chemists  held  out  bravely'  for  timgstic  acid,  relying  on  its  high  molecu- 
lar weight,  it  had  to  yield  to  phosphoric.  Tannic  acid,  which  gives  good 
weightings  with  oxide  of  tin,  can  only  be  used  after  the  last  bath,  and  is 
unsuitable  for  many  dyes. 

Another  discovery  was  that  silicate  of  soda  formed  an  excellent  founda- 
tion for  weighting,  and  again  we  are  ignorant  of  where,  or  by  whom,  the 
discover}'  was  made.  It  is  quite  certain  that  it  much  increases  the  tin 
phosphate  weighting  when  used  together  with  it.  The  discovery  was 
published  first  in  Germany,  in  H.  J.  Neuhaus's  patent  of  January  25,  1903. 
Hotly  contested  lawsuits  have  shown,  however,  that  Neuhaus  was  not 
the  first  to  work  the  process  in  Germany,  and  that  it  had  been  known  and 
worked  for  about  a  year  before  he  patented  it.  The  patent  therefore 
became  void,  and  the  process  common  propert}'.  Great  as  is  the  amount 
of  tin  absorbed  by  silk,  the  use  of  the  silicate  of  soda  makes  it  still  greater. 
Weightings  up  to  40  percent  are  obtained,  but  the  silicate  is  useless  except 
on  a  foundation  of  oxide  or  phosphate  of  tin. 

It  is  kno^TQ  that  metallic  weightings  injure  the  silk  very  much  under 
certain  circumstances,  but  it  is  also  certain  that  the  extent  of  the  injury 
is  not  always  proportional  to  the  degree  of  weighting,  but  that  small 
weighting  is  often  more  injurious  than  much  heavier  loads  of  other  kinds, 
i.e.,  that  the  nature  of  the  weighting  is  as  important  as  its  amount.  Experi- 
ence has  taught,  in  short,  that  stable  and  inert  bodies  are  best,  especially 
when  associated  with  an  organic  body  such  as  tannin.  Hence  a  tin 
phosphate  load  is  better  than  one  of  a  free  metallic  oxide,  and  yet  better 
if  accompanied  by  tannin.  Inasmuch,  however,  as  it  is  sometimes  inad- 
visable to  use  phosphoric  acid,  and  sometimes  objectionable  to  use  tannin, 
a  great  variety  of  loading  processes  have  been  invented,  each  being  fitted 
for  some  special  purpose. 

Weighted  silk  is  more  susceptible  to  deterioration  by  the  action  of 


WEIGHTING  OF  SILK  311 

various  agents  than  untreated  silk.  High  temperatures,  such  as  are  some- 
times reached  in  the  course  of  finishing  operations,  may  cause  a  dehydra- 
tion of  the  weighting  materials  and  thus  produce  weakness  in  the  fiber. 
Chlorides  are  particularly  active  in  causing  tenderness  in  weighted  silk. 
Meister  and  Gianoh  have  both  shown  that  this  destructive  action  of 
chlorides  could  be  more  or  less  completely  neutralised  by  treating  the 
silk  with  potassium  or  ammonium  suKocj^anate.  Sisley  ^  has  shown  that 
suKocarbamide  can  be  used  with  even  better  advantage.  The  amount 
of  the  reagent  to  use  is  about  3  percent  on  the  weight  of  the  silk.  This 
method  is  now  quite  largel}'  emplo3'ed  in  the  treatment  of  weighted  silks 
and  the  protective  effect  is  quite  remarkable.  The  economic  side  of 
weighting  is  of  great  importance  on  account  of  the  high  price  of  tin.  All 
waste  of  tin  must  be  prevented.  In  the  early  days  of  tin  weighting, 
metal  was  lost  by  throwing  away  the  rinse  water  after  wringing.  Soon, 
however,  means  were  found  for  recovering  the  tin  from  the  rinse  in  the 
form  of  oxide.  This  saves  as  much  tin  as  goes  into  the  silk.  Special 
machinery,  too,  has  been  invented  to  enable  the  baths  to  be  used  to 
greater  advantage,  to  save  waste  by  dripping,  etc.,  and,  by  means  of 
pressure  and  centrifuging,  to  remove  as  much  as  possible  of  the  excess  of 
liquor  for  use  on  more  silk,  before  it  is  diluted  by  rinsing.  The  rinse 
water  may  also  be  used  for  making  fresh  weighting  baths.  Heermann  ^ 
states  that  the  conclusion  of  Bayerlein,  that  metastannic  acid  is  at  no 
time  formed  in  the  weighting  of  silk,  is  unfounded;  the  amount  of  meta- 
stannic acid  in  tin  baths  increases  as  the  concentration  decreases.  The 
opalescence  observed  in  tin  solutions  is  due  to  metastannic  acid.  The 
most  reliable  test  for  metastannic  acid  in  this  connection  is  the  white 
voluminous  precipitate  which  appears  in  a  solution  containing  a  calcium 
salt  upon  being  made  alkaline,  and  this  does  not  disappear  on  heating. 

In  the  practical  working  of  the  sUicate  weighting  it  was  soon  found 
that  it  was  advantageous  to  interv^ene  with  a  bath  of  alumina  or  zinc 
between  the  last  phosphate  and  the  last  silicate  bath.  If  this  extra 
bath  is  used  in  moderation,  the  valuable  qualities  of  the  silk  are  not 
perceptibly  affected,  but  a  considerable  increase  in  the  weighting  is  cheaply 
attained.  Followdng  out  this  experience,  manufacturers  substituted  baths 
of  other  metals  for  the  successive  tin  baths,  to  a  greater  and  greater  extent, 
until  at  last  onh'  the  first  metal  bath  was  of  tin.  This  has  led  to  many 
variations  in  the  weighting  process  which  can  be  traced  in  the  patents 
concerned  with  them.  Lead,  bismuth,  nickel,  copper,  manganese,  and 
antimony  have  all  been  tried. 

Another  direction  which  research  has  taken  is  toward  fixing  oxide  of 
tin  on  the  fiber  in  the  form  of  various  insoluble  salts  of  organic  and  inor- 

1  Rev.  Gen.  Mat.  Col,  vol.  13,  p.  33 

2  parb.  Zeit.,  1910,  p.  318. 


312  CHEMICAL  NATURE  AND  PROPERTIES  OF  SILK 

ganic  acids  by  the  use  of  all  manner  of  soluble  salts  of  the  acids;  no  useful 
result  has  been  achieved  along  this  line.  Yet  another  consists  in  trying 
to  fix  inert  bodies  upon  the  silk  by  means  of  albumen,  glue,  etc.,  made 
insoluble  with  formaldehyde,  or  with  a  salt  of  iron  or  chromium.  These 
last  processes  have  the  advantage  that  the  fiber  is  not  injured  so  far  as  its 
strength  and  elasticity  are  concerned,  but  have  the  drawback  that  they 
impart  an  utterly  unnatural  appearance  to  the  silk,  as  soon  as  any  weight- 
ing worth  having  has  been  incorporated.  The  luster  is  entirely  ruined, 
as  the  surface  of  the  silk  is  effectually  masked.  Finally,  the  cost  of  these 
loadings  is  great  in  proportion  to  the  increase  in  weight  given  to  the  silk. 

All  these  researches  have  been  virtually  useless,  and  manufacturers 
are  going  back  more  and  more  to  loading  with  tin,  in  combination  with 
phosphoric,  silicic,  and  tannic  acids.  The  only  practical  success  that  has 
been  achieved  is  to  replace  a  little  of  the  tin  by  alumina. 

The  best  way  to  apply  the  tin  is  probably  in  the  form  of  chloride, 
although  tin  sulfite  {Ger.  Pat.  30,597)  is  in  some  respects  superior  to 
the  chloride.  It  gives  more  metal  to  the  fiber.  A  very  recent  invention 
{Ger.  Pat.  163,322)  is  to  combine  the  tin  chloride  with  sulfates,  espe- 
cially glaubersalt  and  sulfate  of  alumina,  but  there  has  not  yet  been 
sufficient  experience  of  the  process  to  enable  us  to  judge  of  its  value. 

Chittick  calls  attention  to  the  fact  that  the  real  amount  of  weighting — 
that  is,  the  percentage  of  adulterant  added  to  the  silk  fiber,  will  depend 
on  the  amount  of  gum,  soap,  and  oil  that  the  thrown  silk  loses  in  the  boil- 
off.  Most  manufacturers  have  no  real  idea  of  the  amount  of  loading 
they  are  putting  on  their  silks,  as  they  seldom  have  a  boil-off  test  made 
on  their  thrown  silk.  If  silk,  for  example,  was  ordered  to  be  weighted 
22/24  ozs.  (which  means  that  16  ozs.  of  thrown  silk  when  dyed  must 
weigh  not  less  than  22  ozs.  nor  more  than  24  ozs.)  it  might  happen  that 
one  lot  of  Japan  silk  would  have  a  natural  boil-off  of  16  percent,  that 
2  percent  of  soap  and  oil  had  been  added  by  the  throwster,  and  that  the 
weight  returned  by  the  dyer  might  be  just  22  ozs.  Another  lot  might 
have  a  natural  boil-off  of  20  percent,  the  throwster  might  have  added 
4  percent  of  soap  and  oil,  and  the  return  from  the  dyer  might  be  the 
full  24  ozs.  Now  the  manufacturer  thinks  that  both  silks  are  weighted 
the  same,  yet  the  first  lot  would  have  been  actually  weighted  only  67.68 
percent,  whereas  the  second  lot  would  be  loaded  97.36  percent. 

As  regards  the  influence  of  tin  weightings,  whether  simple  or  mixed, 
upon  dyeing,  they  are  all  perfectly  suitable  for  any  color,  and  both  for 
cuit  and  souple  silks.  The  black-dyer  is  less  dependent  than  others  on  the 
weighting,  as  he  uses  substances  like  tannin  and  iron  salts,  which  them- 
selves act  as  loaders.  These  bodies  are  barred  to  the  color  dyer  for  the 
most  part,  as  they  darken  the  fiber,  and  he  is  confined  to  bleached  tannin, 
alumina,  and  colorless  salts.     Tannin  is  dear,  always  darkens  the  fiber,  and 


TUSSAH  SILK  313 

does  not  give  enough  weight  alone,  although  it  gives  far  more  than  alumina 
or  salts.  In  short,  modern  silk-dyeing  is  impossible  without  tin  weighting. 
Tin  can  be  applied  at  any  stage  of  the  preparation  of  the  silk,  or  raw  silk, 
to  souple,  or  to  boiled-off  silk.  Tinned  raw  silk  can  be  scoured,  without 
losing  more  tin  than  corresponds  to  the  percentage  of  bast  removed.  It 
can  be  mordanted  with  iron,  alumina,  or  chrome,  and  can  be  further 
weighted  with  Prussian  Blue,  and  finally  it  can  be  dyed  with  natural 
coloring  matters,  or  the  coal-tar  dyes. 

Silk-weighting  is  the  basis  of  modern  silk-dyeing.  Any  serious  struggle 
against  it  is  a  hopeless  fight  against  natural  development  and  progress, 
is  based  on  mistaken  ideas,  and  can  only  be  useful  against  an  exaggerated 
and  irrational  loading  of  the  fiber. 

14.  Tussah  Silk  presents  a  number  of  differences,  both  physical  and 
chemical,  from  ordinary  silk.  It  has  a  brown  color  and  is  considerably 
stiffer  and  coarser.  It  is  less  reactive,  in  general,  toward  chemical  reagents, 
and  consequently  presents  more  difficulty  in  bleaching  and  dyeing.  Tussah 
silk  requires  a  much  more  severe  treatment  for  degumming  than  cultivated 
silk,  and  the  boiled-off  liquor  so  obtained  is  of  no  value  in  dyeing. 
.  •  Tussah,  or  tussur,  silk  is  largely  used  in  the  weaving  of  a  pile  fabric 
known  as  "  sealcloth,"  which  consists  of  a  tussah  silk  plush  woven  into  a 
cotton  back,  and  is  a  material  of  most  useful  character  for  wraps  and 
mantles.  It  is  a  fabric  having  a  rich  and  handsome  appearance,  and, 
if  injured  by  wetting  or  pressing,  is  readily  restored  by  drying  before  a 
fire  and  brushing.  Tussah  silk  is  also  extensively  used  for  rug  and  carpet 
making,  and  as  its  fiber  is  nearly  three  times  as  thick  as  mulberry  silk  it 
gives  a  much  firmer  and  better  pile.  It  is  also  used  in  the  manufacture  of 
woven  cloths  such  as  "  Mandarine "  and  "  Grenadine "  fabrics.  It 
furthermore  finds  extensive  use  for  fringes,  damasks,  millinery  pompons, 
tassels  and  cords,  chenille  for  upholstery,  and  for  embroidery  silks. 

According  to  analyses  of  Bastow  and  Appleyard,^  raw  tussah  silk  gives 
the  following  results : 

Percent. 

Soluble  in  hot  water 21 .  33 

Dissolved  by  alcohol  (fatty  acid) 0.91 

Dissolved  by  ether 0 .  08 

Total  loss  on  boiling  off  with  1  percent  solution  of  soap . .   26 .  49 
Mineral  matter 5 .  34 

These  same  observers  consider  that  the  fibroine  of  tussah  silk  differs  chem- 
ically from  that  of  ordinary  silk,  as  it  is  not  so  readily  acted  on  bj'  solvents. 
In  order  to  obtain  pure  tussah  fibroine,  the  silk  should  be  boiled  repeatedly 
with  a  1  percent  solution  of  soap,  washed  with  water,  extracted  with  hydro- 
chloric acid;  and  after  again  washing  with  water  and  drying,  extracted 
*  Jour.  Soc.  Dyers  &  Col.,  vol.  4,  p.  88. 


314  CHEMICAL   NATURE  AND   PROPERTIES   OF  SILK 

successively  with  alcohol  and  ether.     Tussah  fibroine  purified  in  this  man- 
ner shows  the  following  composition : 

Percent. 

Carbon 47. 18 

Hydrogen 6 .  30 

Nitrogen 16 .  85 

Oxygen 29.67 

These  figures  are  exclusive  of  0.226  percent  of  ash.  Appleyard  gives 
the  following  analysis  of  the  ash  from  raw  tussah  silk. 

Percent. 

Soda,  NasO 12.45 

Potash,  KoO 31 .  68 

Alumina,  AI2O3 1 .  46 

Lime,  CaO 13.32 

Magnesia,  MgO 2.56 

Phosphoric  acid,  P2O6 6 .  90 

Carbonic  acid,  CO2 11 .  14 

Silica,  Si02 9.79 

Hydrochloric  acid,  CI 2.89 

Sulfuric  acid,  SO3 8. 16 

The  presence  of  sulfates  in  this  ash  is  somewhat  remarkable,  as  this 
constituent  does  not  occur  in  ordinary  silk.  The  occurrence  of  alumina 
is  also  remarkable,  as  this  element  is  seldom  a  constituent  of  animal 
tissues.  As  the  amount  of  ash  of  purified  fibroine  of  both  common  silk 
and  tussah  silk  is  very  much  lower  than  that  of  the  raw  silks,  it  is  to  be 
considered  probable  that  most  of  the  mineral  matter  found  is  derived 
from  adhering  impurities,  and  is  not  a  true  constituent  of  the  silk  itself. 

Tussah  silk  is  scarcely  affected  by  an  alkaline  solution  of  copper  hydrate 
in  glycerol,  whereas  ordinary  silk  is  readily  soluble  in  this  reagent.^ 

Shroff  ^  describes  the  properties  of  a  variety  of  oriental  wild  silk  in 
the  manufactured  form.  The  cloth  examined  is  often  spoken  of  as 
"  Kashmere  silk,"  and  was  of  a  yellow-reddish  tint.  It  was  almost  en- 
tirely unaffected  by  concentrated  hydrochloric  acid,  chromic  acid  and 
zinc  chloride,  all  of  which  dissolved  mulberry  silk.  The  action  of  boiling 
10  percent  caustic  soda  was  slow.  Soda  ash,  and  soap,  both  followed  by 
hydrogen  peroxide,  partly  bleached  it,  reducing  the  luster.  Hydrogen 
peroxide  and  sodium  silicate  preserved  the  luster  and  were  equally  good 
in  reducing  the  color.  The  best  result  was  obtained  by  boiling  with 
1°  Tw.  hydrochloric  acid,  then  treating  with  3°  Tw.  caustic  soda  for  a  few 
minutes  and  finally  with  |°  Tw.  ammonium  hypochlorite,  washing  after  each. 

The  following  table  exhibits  the  principal  differences  between  true  silk 
and  tussah  silk:^ 

1  Filsinger,  Chem.  Zeit.,  vol.  20,  p.  324. 

2  Posselt's  Text.  Jour.,  1922. 

'  Bastow  and  Appleyard,  Jour.  Soc.  Dyers  &  Col.,  vol.  4,  p.  89. 


TUSSAH  SILK 


315 


Reagent. 

Mulberry  Silk. 

Tussah  Silk. 

Hot  caustic  soda  (10  percent) 

Dissolves  in  12  minutes 

Requires    50    minutes    for 
solution 

Cold  hydrochloric  acid   (sp.  gr. 

Dissolves  very  rapidly 

Only  partially  dissolves  in 

1.16) 

48  hours 

Cold  cone,  nitric  acid 

Dissolves  in  5  minutes 

Dissolves  in  10  minutes 

Neutral  solution  of  zinc  chloride 

Dissolves  very  rapidly 

Dissolves  but  slowly 

(sp.gr.  1.725) 

Strong  chromic  acid  solution  in 

Dissolves  very  rapidly 

Dissolves  very  slowly 

water 

While  the  fiber  of  mulberry  silk  presents  the  appearance  of  a  structure- 
less thread,  and  rarely  exhibits  signs  of  distinct  striation,  tussah  (as  well 
as  other  "  wild  "  silks)  is  made  up  of  bundles  of  delicate  fibrillae,  varying 
in  diameter  from  0.0003  to  0.0015  mm.,  so  that  the  fiber  as  a  whole  presents 
a  striated  appearance.  Also  the  cross-section  of  tussah  silk  is  considerably 
larger  than  that  of  mulberry  silk,  and  is  more  flattened;  it  also  exhibits 
numerous  fine  air-tubes.  The  following  table  exhibits  the  difference  in  the 
microscopic  appearance  of  various  kinds  of  raw  silk:^ 


Variety  of  Silk. 

Diameter, 
Microns. 

Appearance. 

Broad  Side. 

Narrow  Side. 

True  sUk,  Bombyx 

mori 
Senegal    silk,     B. 

faidherbi 

Allan  thus  silk,  .4^ 
tacus  cynthia 

Yama-mai  silk, 
Anther oEa  yama- 
mai 

Tussah  silk,  Atta- 
cus  selene 

Tussah    silk,    An- 
theroea  mylitta 

20  to  25 
30  to  35 

40  to  50 
40  to  50 
50  to  55 

60  to  65 

White  or  yellowish ;  shiny 

Shining  yellowish  or  brown- 
ish white,  or  pale  yellow, 
gray,  brown,  and  occasion- 
ally bluish  white 

Shining  yellowish  white, 
with  yellow,  brown,  or 
brownish  gray  spots 

Bluish  white  with  dark  blue, 
blue  and  black  shades 

Irregular  in  thickness. 
Thickest  parts  with  gray 
and  blue  spots;  thinner 
parts  bluish  white,  yellow, 
or  orange-red 

Similar  to  above,  but  spots 
orange-red,  red,  or  brown 

White  or  yellowish;  shiny 

Gray,  brown,  or  black,  with 
occasionally  lighter  shades 

Dirty  gray  or  brown  to 
black,  with  green,  yellow, 
red,  violet,  or  blue  spots 

Glaring  and  fine  colors,  with 
dark  or  black  shades 

Dark    gray,    with   pink   or 
light  green  spots 

Similar  to  above 

1  Hohnel,  Jour.  Soc.  Chem.  Ind.,  vol.  2,  p.  172. 


316 


CHEMICAL  NATURE  AND  PROPERTIES  OF  SILK 


The  cocoon-thread  of  wild  silks  possess  greater  elasticity  and  tensile 
strength,  as  would  naturally  be  expected  from  their  greater  thickness. 
The  following  table  gives  the  elasticity  and  breaking  strain  of  the  principal 
varieties  of  silk: 


Variety  of  Silk. 


Mulberry  {Bombyx  mori) .  . 
Tussah  {Anthercea  mylitta) . 

Eria  {Attacus  ricini) 

Muga  {Anther oea  assama) . . 

Atlas  (Attacus  altas) 

Ailanthus  (Attacus  cynthia) 

Yama-mai 

Attacus  selene 

Antheroea  pernyi 


Elasticity, 

Breaking  Strain, 

Percent. 

Grams. 

13.3 

4.5 

19.1 

12.8 

15.0 

4.0 

21.7 

6.7 

19.1 

5,6 

22.5 

4.9 

25.0 

12.8 

20.0 

5.6 

19.1 

8.1 

Muga  (or  moonga)  silk  is  a  wild  silk  next  in  importance  and  value 
to  tussah.  It  is  indigenous  to  Assam,  but  is  also  to  be  found  in  some  other 
provinces.  The  fiber  is  fawn-colored  when  the  worm  feeds  on  the  common 
plants  in  the  districts  of  which  it  is  a  native,  but  gives  a  whiter  and  better 
quality  of  fiber  when  fed  on  leaves  on  which  other  silkworms  are  reared. 
Champa-fed  worms  produce  the  celebrated  champa  pattea  moonga,  a  very 
fine  quality  of  white  silk  used  only  by  the  rajahs. 

Eria  silk  is,  perhaps,  the  third  in  importance  among  the  wild  silks. 
It  is  produced  by  a  worm  which  feeds  on  the  castor-oil  plant,  and  like  the 
muga  silk  is  indigeneous  to  Assam,  but  is  also  found  in  other  districts. 
In  Assam  the  fiber  is  white,  but  in  Singapore  it  is  brown.  Eria  silk  does 
not  dye  very  readily,  being  inferior  in  this  respect  to  tussah.  Owing  to  its 
rather  loose  cocoon,  eria  silk  cannot  be  reeled,  but  has  to  be  spun  after 
being  combed. 

Other  varieties  of  wild  silk  are  the  Bombyx  textor,  known  as  the  "  pat  " 
silkworm,  a  native  of  Assam.  It  is  probably  a  variety  of  the  B.  mori, 
though  its  cocoon  is  of  a  different  shape  and  is  yellow  in  color.  The  silk 
is  of  excellent  quality  and  is  quite  valuable. 

The  Cricula  trifenestrata  is  abundant  in  British  Burma,  where  the 
cocoons  literally  rot  in  the  jungles  for  want  of  gathering.  The  silk  is 
strong,  rich  and  lustrous;  it  is  spun  in  the  same  way  as  Eria  silk  and  is 
yellow  in  color. 

15.  Byssus  Silk. — This  is  also  known  as  "  sea-silk  "  or  "  pinna  silk," 
and  is  obtained  from  a  marine  mollusk,  Penna  nobilis,  and  related  varieties. 
The  shell-fish  possesses  a  long  slender  gland  which  secretes  woolly  fibers 
known  as  the  Byssus  or  "  beard."     These  fibers  are  of  a  brown  color  and 


BYSSUS  SILK 


317 


are  4  to  6  cm.  in  length.  The  brown  color  is  said  to  be  due  to  an  external 
covering  which  when  removed  leaves  a  colorless  fiber.  Sea-silk  is  some- 
what used  in  southern  Italy  and  in  Normandy  for  the  making  of  various 
ornamental  braided  articles.  Though  this  fiber  somewhat  resembles  silk 
in  appearance,  it  is  easily  distinguished  by  the  presence  of  natural  rounded 
ends.  The  fibers  vary  considerably  in  diameter  (10  to  100  microns)  and 
are  ellipitical  in  cross-section  (Fig.  149),  and  are  often  twisted.  Fine 
longitudinal  striations  are  apparent,  but  as  the  fiber  is  solid  no  empty 
lumen  or  air  canals  are  present.    The  finer  fibers  are  smooth,  but  the 


Fig.  149. — Fiber  horn  Petma  nobilis.     (XlOO.)     (Micrograph  by  author.) 


coarser  ones  are  rough  and  corroded.     Frequently  very  delicate  fibrils 
are  to  be  observed  branching  from  the  larger  fibers. 

The  manufacture  of  materials  from  pinna  silk  was  carried  on  at  Taranto 
in  Italy.  The  "  fish  wool  "  (as  it  was  called)  was  washed  twice  in  water, 
once  in  soap  and  water,  and  again  in  tepid  water,  and  finally  spread  out 
on  a  table  to  dry.  While  yet  moist  it  was  rubbed  and  separated  with  the 
hands  and  again  spread  on  the  table  to  dry.  When  quite  dry  it  was 
drawn  through  a  wide  bone  comb  and  then  through  a  narrow  one.  It 
was  then  spun  into  a  yarn  with  distaff  and  spindle.  As  it  was  not  possible 
to  procure  much  of  the  material  of  good  quality  the  manufacture  was 
limited  to  a  few  articles  such  as  gloves  and  stockings,  and  these  were 


318  CHEMICAL   NATURE   AND   PROPERTIES   OF   SILK 

quite  expensive.     The  fabrics  were  very  soft  and  warm  and  of  a  brown 
or  glossy  gold  color. ^ 

Another  animal  fiber  of  a  somewhat  silklike  nature  is  the  so-called 
"  sineiv  fiber."  This  product  is  obtained  from  sinews  which  consists  of 
fibrous  connective  tissue  made  up  of  wavy  elements  united  in  bundles. 
Hanausek  ^  calls  attention  to  the  fact  that  sinew  fiber  was  utilised  in  ancient 
times,  the  Israelites  using  a  yarn  twisted  from  sinews  under  the  name  of 
"  gidden  "  for  their  religious  rites.  In  recent  years  sinew  fiber  has  been 
spun  into  yarns  by  mixing  with  wool  or  hemp.  The  fiber  is  very  silky  in 
luster  and  varies  much  in  length  (from  3  to  18  cm.).  Such  yarns  have 
great  tensile  strength  and  are  rough  in  feel. 

^  Gilroy,  History  of  Silk,  etc.,  p.  182. 

-  Microscopy  of  Technical  Products,  p.  150. 


CHAPTER  XII 
THE  VEGETABLE  FIBERS 

1.  Origin  of  Vegetable  Fibers. — Probably  there  is  no  one  thing  more 
used  in  common  life  and  with  which  the  average  individual  comes  more 
in  contact  than  vegetable  fibers.  These  materials  are  used  broadly  for 
all  kinds  of  clothing  and  underwear,  for  household  fabrics,  for  sheetings 
and  towelings,  and  for  all  manner  of  purposes  far  too  numerous  to  mention ; 
and  yet  outside  of  the  fact  that  the  material  is  cotton  or  linen — and  even 
this  fact  may  sometimes  be  in  doubt — it  is  questionable  if  the  layman  is 
at  all  famiHar  with  the  general  nature  and  structm-e  of  these  vegetable 
fibers. 

All  vegetable  tissues  are  made  up  of  cells,  and  in  most  cases  these  cells 
are  very  minute  in  size  and  delicate  in  structure.  This  is  true  of  vegetable 
fiber  as  well  as  of  other  tissues  of  the  plant.  Cotton  is  rather  remarkable 
in  this  connection,  as  it  consists  of  a  single  elongated  cell,  and  in  its  intimate 
structure,  therefore,  differs  quite  radically  from  linen  and  most  other 
vegetable  fibers,  in  that  these  consist  of  a  bundle  or  number  of  individual 
small  cells  that,  cemented  together  by  other  vegetable  tissue,  go  to  make 
up  the  commercial  fiber. 

Jute,  hemp,  China  grass,  as  well  as  the  various  cordage  fibers,  belong 
in  the  same  category  as  linen  as  far  as  structure  is  concerned.  These  all 
consist  of  a  large  niunber  of  tiny  cells  compacted  together  to  form  an 
individual  fiber.  It  is  easy  to  understand,  therefore,  why  a  weakening 
of  the  fiber  is  caused  in  such  cases  by  subjecting  it  to  processes  of  bleaching 
or  other  chemical  treatments.  The  effect  is  usually  to  dissolve  or  disin- 
tegrate the  cementing  laj^ers  that  hold  the  cells  together,  and  thus  the 
fiber  is  weakened  and  broken  up  into  its  small  elements.  Cotton,  being 
a  single  integral  cell,  is  thus  more  capable  of  resisting  the  action  of  such 
agents  than  the  other  fibers. 

The  basis  of  all  vegetable  fibers  is  to  be  found  in  cellulose,  a  compound 
belonging  to  a  class  of  naturally  occurring  substances  known  as  carbohy- 
drates. It  is  seldom,  however,  that  cellulose  actually  occurs  in  the  plant 
in  the  free  condition,  but  is  usually  associated  or  chemically  combined 
M  ith  other  substances,  of  which  the  principal  are  fatty  and  waxy  matters, 
coloring  matters,  and  tannins,  and  a  rather  indefinite  group  of  so-called 
pectin  matters,  which  appear  to  be  more  or  less  oxidised  or  acid  derivatives 

319 


320  THE  VEGETABLE  FIBERS 

of  the  carbohydrates.  The  fibers  may  be  seed-hairs,  such  as  the  different 
varieties  of  cotton,  cotton-silk,  etc.;  or  bast  fibers,  which  include  those 
obtained  from  the  cambium  layer  of  the  dicotyledonous  plants,  such  as 
flax,  hemp,  jute,  ramie,  etc.;  or  vascular  fibers,  which  include  those 
obtained  chiefly  from  the  leaf-tissues  of  the  monocotyledonous  plants, 
such  as  phormium,  agave,  aloe,  etc. 

The  terms  ''  dicotyledonous  "  and  "  monocotyledonous  "  refer  to 
plants  the  seeds  of  which  have  two  lobes  and  one  lobe  respectively.  A 
dicotyledonous  plant  is  also  an  exogen  or  outside  grower,  familiar  examples 
of  which  are  ordinary  trees  or  shrubs.  Monocotyledonous  plants,  on  the 
other  hand,  are  endogens,  or  inside  growers,  such  as  grasses,  palms,  lilies, 
etc.  The  stalk  of  the  monocotyledonous  plant  is  really  the  residue  of 
the  successive  leaf-sheaths,  whereas  the  stalk  of  the  dicotyledonous  plant 
is  a  separate  growth  entirely  distinct  from  the  leaf.  In  China  there  is  an 
example  of  a  spinning  fiber  composed  of  the  leaf-hairs  of  a  plant.  The 
latter  apparently  belongs  to  the  Xeranthemum,  and  its  leaves  are  covered 
with  a  thick  mass  of  long  hairy  fibers,  which  are  easily  separated  from  the 
leaf  when  dried.  There  is  peculiar  instance  in  which  the  entire  plant  is 
used  as  the  fiber;  this  is  sea-grass  or  sea- wrack  (Zostera  manna).  How- 
ever, it  can  scarcely  be  considered  as  a  textile  fiber,  as  it  is  almost  together 
employed  for  stuffing  and  packing. 

Anatomically  considered,  the  plant  fibers  may  be  divided  into  six 
different  classes  (Hohnel): 

1.  Seed-hairs  of  a  single  cell,  such  as  cotton,  vegetable  silk,  and  vegetable  down. 

2.  Seed-hairs  consisting  of   several  cells,  such  as  pulu  fiber,  elephant-grass,  and 
cotton-grass. 

3.  Bast  fibers,  such  as  flax,  hemp,  jute,  ramie,  etc. 

4.  Dicotyledonous  bast  fibers,  such  as  Hnden  bast,  Cuba  bast,  etc. 

5.  Monocotyledonous  vascular  fibers,  such  as  sisal  hemp,  aloe  hemp,  pineapple 
fiber,  cocoanut  fiber,  etc. 

6.  Monocotyledonous  sclerenchymous  fibers,  such  as  Manila  hemp,  New  Zealand 
flax,  etc. 

Depending  on  the  portion  of  the  plant  from  which  the  fiber  is  derived, 
the  following  classification  may  be  used: 

1.  Seefl  fibers,  growing  from  the  seeds  or  seed-capsules  of  certain  plants,  and 
including  cotton,  vegetable  silk,  etc. 

2.  Stem  fibers,  growing  in  the  bast  of  certain  dicotyledonous  plants,  and  including 
flax,  hemp,  jute,  etc. 

3.  Leaf  fibers,  occurring  in  the  leaves  of  a  number  of  monocotyledonous  plants,  and 
including  New  Zealand  hemp,  Manila  hemp,  aloe,  etc. 

4.  Fruit  fibers  of  which  the  sole  member  worth  mentioning  is  the  cocoanut  fiber. 

2.  Seed-hairs  and  Bast  Fibers. — There  is  considerable  difference  to 
be  observed  between  the  anatomical  structure  of  seed-hairs  and  that  of 


SEED-HAIRS  AND  BAST  FIBERS  321 

bast  fibers.  Seed-hairs  are  known  botanically  as  plumose  fibers,  and 
usually  consist  of  a  unicellular  fiber  exhibiting  only  a  single  solid  apex, 
the  other  end  being  attached  to  the  seed.  Externally  they  appear  to  be 
covered  with  a  thin  skin  or  cuticle  which  differs  essentially  from  the 
remaining  cellulose  in  that  it  is  not  dissolved  by  treatment  with  sulfuric 
acid.  The  cell-walls  vary  considerably  in  their  thickness,  and  are  struc- 
tureless and  porous.  Through  the  center  of  the  fiber  runs  a  hollow  canal 
called  the  lumen.  Usually  the  dried  fiber  is  flattened  into  the  form  of  a 
band,  so  that  in  cross-section  the  lumen  appears  as  a  line.  The  inner 
surface  of  the  cell-wall  is  also  coated  with  a  very  thin  laj^er  of  dried  pro- 
tein matter  which  is  very  adhesive,  and  which  remains  undissolved  like  the 
cuticle  after  the  solution  of  the  fiber  in  sulfuric  acid.  Bast  fibers,  on  the 
other  hand,  consist  of  completely  enclosed  tubes,  each  end  being  pointed. 
Each  individual  fiber  is  multicellular,  the  cells  being  long  and  usually 
polygonal  in  cross-section.  The  cell- walls  are  usually  rather  thick,  and 
the  cross-section  instead  of  being  flat  and  narrow  is  broad  and  more  or  less 
rounded.  The  inner  wall  is  frequently  covered  with  a  thin  layer  of  dried 
protein.  The  bast  or  vascular  bundles  consist  of  two  parts,  the  phloe?n 
and  the  xylem.  As  a  rule,  the  phloem  occurs  nearer  the  outside  of  the 
plant,  while  the  xylem  forms  the  principal  structural  part  of  the  inside 
portion  of  the  plant.  The  fibers  in  the  phloem  are  usually  rather  easily 
detached  and  form  the  commercial  product,  while  those  occurring  in  the 
xylem,  as  a  rule,  cannot  be  readily  separated  by  m'echanical  means  from 
the  woody  tissue  in  which  they  are  imbedded. 

One  of  the  most  characteristic  appearances  of  the  bast  fibers  is  the 
occurrence  of  dislocations  or  joints  throughout  the  length  of  the  fiber 
(Figs.  150  and  151).  These  dislocations  show  the  property  of  becoming 
more  deeply  colored  than  the  rest  of  the  fiber  when  treated  with  a  solution 
of  chlor-iodide  of  zinc.  These  knots  or  joints  generally  show  thicker 
overlying  transverse  fissures,  between  which  lie  small  short  disks  arranged 
on  edge.  The  joints  disappear  altogether  in  the  sclerenchymous  or  leaf 
fibers  such  as  New  Zealand  flax,  Manila  hemp,  sisal,  etc.;  they  are  also 
lacking  on  many  true  bast  fibers,  such  as  jute,  linden  bast,  etc.;  but 
occm"  in  hemp,  flax,  ramie,  etc.  These  joints  or  knots  are  no  doubt 
caused  while  the  fiber  is  still  in  the  growing  plant,  by  an  imequal  cell 
pressure. 

The  structure  of  bast  fibers  may  also  be  shown  by  treatment  with  a 
reagent  recommended  by  Haller  {Textile  Forschnng,  1920,  p.  22).  The 
bast  fibers  are  immersed  for  several  hours  in  an  acidified  10  percent  solution 
of  stannous  chloride,  well  washed,  and  treated  with  a  10  percent  solution 
of  gold  chloride.  The  separating  surfaces  between  the  fiber  cells  become 
1  nownish  red  in  color  and  the  structure  may  be  easily  seen.  This  reaction 
may  be  employed  in  connection  with  fibers  of  jute,  hemp,  flax,  and  typha. 


322 


THE   VEGETABLE   FIBERS 


There  are  several  other  methods  that  may  be  employed  for  exhibiting 
the  structure  of  vegetable  fibers.  One  that  has  been  extensively  employed 
is  examination  in  polarised  light  after  causing  the  fiber  to  swell  by  treat- 
ment with  strong  caustic  soda  solution.  Nodder  ^  also  describes  the  fol- 
lowing method :  The  fiber  to  be  examined  is  mounted  in  a  strong  calcium 
chloride  solution  which  has  been  tinted  a  pale  yellowish  brown  color  by  the 


Fig.  150. 


Fig.  151. 


Fig.  150.— a  Typical  Bast  Fiber  ( X350),  Showing  the  Jointed  Structure  or  Dislocations 
at  D.     (Micrograph  by  author.) 

Fig.  151.— A  Bundle  of  Bast  Fibers.     (X400.)     (After  Lecomte.) 


addition  of  iodine.  While  the  fiber  is  being  examined  under  moderately 
low  magnification,  pressure  is  exerted  on  the  cover  glass,  any  lateral 
movement  being  carefully  avoided.  With  care  and  practice  the  fiber 
may  often  be  squeezed,  without  breaking  the  cover  glass,  until  its  width  is 
increased  as  much  as  ten  to  fifteen  times.  The  fibrillar  structure  will 
then  be  well  displayed  and  the  growth  layers  of  the  cell-wall  will  become 


1  Jour.  Text.  Inst.,  1922,  p.  163. 


DIMENSIONS  OF  FIBER  CELLS  323 

widely  separated  and  distinctly  visible.  The  non-visibility  of  the  fibrils 
under  ordinary  microscopic  examination  is  presumably  due  to  the  fact 
that  they  are  so  close  together  as  to  be  beyond  the  resolving  power  of  the 
microscope,  but  by  distending  the  fiber  in  the  manner  described  the 
separate  fibrils  are  brought  within  the  limits  of  visibility.  The  dimensions 
of  the  fibrils  in  flax,  as  they  exist  in  the  uncompressed  fiber,  are  estimated 
to  be  about  0.00003  mm.,  that  is  to  say  there  are  about  1000  of  these 
fibrils  across  the  width  of  the  fiber.  When  linen  is  treated  in  the  manner 
above  described  by  Nodder  the  fibrils  are  seen  to  form  left-handed  spirals, 
and  the  same  is  also  true  with  ramie;  with  hemp,  however,  the  fibrils 
always  form  right-handed  spirals,  as  does  also  jute.  Cotton  also  exhibits 
a  distinct  fibrillar  structure,  but  shows  both  right-handed  and  left-handed 
spirals  in  different  parts  of  the  same  fiber. 

Bast  fibers  are  the  long,  tough  cells  found  in  the  barks  and  stems  of 
various  plants.  The  cell-walls  of  these  fibers  are  usually  partially  changed 
from  pure  cellulose  into  lignin  and  are  thickened.  There  is  usually  a 
considerable  amount  of  foreign  matter  also  contained  in  the  cell-wall, 
and  often  this  becomes  sufficiently  characteristic  to  serve  as  a  means  of 
identifying  the  various  fibers  by  the  application  of  chemical  reagents. 
Fibers  which  contain  only  pure  cellulose  are  colored  blue  when  treated 
with  the  iodine-sulfuric  acid  reagent,  while  fibers  containing  lignin  are 
colored  yellow  to  brown  by  the  same  test.  The  most  satisfactory  test  for 
lignification  is  that  given  by  Maule  ^  as  follows :  Sections  are  soaked  for 
about  five  minutes  in  a  1  percent  solution  of  potassium  permanganate,  and 
after  washing  in  water,  are  soaked  for  two  to  three  minutes  in  dilute 
hydrochloric  acid,  and  finally  in  ammonia.  All  lignified  parts  assume  a 
red  color  by  this  treatment. 

3.  Dimensions  of  Fiber  Cells. — Unlike  seed-hairs,  the  individual  cells 
of  bast  fibers  are  not  of  sufficient  length  for  use  in  spinning,  but  as  they 
are  held  together  with  considerable  firmness  to  form  bundles  of  great 
length,  they  are  utilised  in  this  form. 

Owing  to  the  difference  in  the  length  of  the  commercial  fiber  elements 
between  seed-hairs  and  bast  fibers,  there  are  very  material  differences  in 
the  methods  of  spinning  these  fibers  into  yarns  and  the  character  of  the 
machinery  required  therefor.  Cotton  cards  and  spinning  frames,  for 
example,  which  are  adapted  for  the  preparation  and  spinning  of  the 
relatively  short  cotton  fibers,  cannot  be  used  for  the  processing  of  linen 
or  ramie,  hemp  or  jute,  but  specially  designed  machines  for  these  fibers 
are  required.  Due  to  the  composite  nature  of  the  bast  fibers,  the  com- 
mercial length,  even  of  the  same  general  class,  may  vary  within  wide 
limits,  and  in  the  case  of  waste  the  fibers  may  be  reduced  to  their  ultimate 
elements. 

'  Beitr.  Wiss.  Bot.,  1900,  vol.  4,  p.  166. 


324 


THE   VEGETABLE   FIBERS 


Wiesner  gives  the  following  table  showing  the  length  of  raw  fibers  and 
the  dimensions  of  the  cells  composing  them: 


Fiber. 


Tillandsia  fiber 

Esparto  grass 

Cordia  latifolia 

Phormium  lenax 

A  belmoschus  tetraphyllos 

Bauhinia  racemosa 

Jute  (Corchorus  capsularis) 

Thespesia  lampas 

Urena  sinuata 

Sida  retusa 

Cnlotropis  gigantea  (bast) 

Aloe  perfoliata 

Flax  (Linum  usitaiissimum) 

Hemp  (Cannabis  sativa) 

Jute  {Corchorus  olitorius) 

Hibiscus  cannalyinus 

Sunn  hemp  (Crotolaria  juncea) .  .  .  . 

Bromelia  karatas 

China  grass  (Boehmeria  nivea) 

Ramie  (Boehmeria  tenacissima) .  .  .  . 
Cotton  (Gossypium  barbadense) . .  .  . 

' '       (G.  conglomeratum) 

* '       (G.  herbaceum) 

* '       (G.  acuminatum) 

' '       (G.  arboreum) 

Cotton  wool  (Bombyx  heptaphyllum 
Vegetable  sUk  (Calotropis  gigantea) 

' '  (Asclepias) 

' '  (Marsdenia) 

' '  (Strophantus) 

' '  (Beaumontia) 

Linden-bast 

Stercidia  villosa 

Holoptelea  integrifolia 

Kydia  calycirva 

Lasiosyphon  speciosus 

Sponia  Wightii 

Pandanus  odoratissimus 

Pita  fiber 

Coir  fiber 


Length  of 

Length 
of 

Raw 

Fiber, 

Cells, 

Cm. 

Mm. 

2-22 

0.2-0.5 

10-40 

1.5-1.9 

50-90 

0.1-1.6 

80-110 

2. .5-5. 6 

60-70 

0.1-1.6 

50-150 

1.5-4.0 

150-300 

0.8-4.1 

100-180 

0.9-4.7 

100-120 

1.1-3.2 

80-100 

0.8-2.3 

20-30 

0.7-3.0 

40-50 

1.3-3.7 

20-140 

2.0-4.0 

100-300 

0.8^.1 

150-300 

0.8-4.1 

40-90 

4.0-12  0 

20-50 

0.5-6.9 

100-110 

1.4-6.7 

22.0 

8.0 

4.05 

40.5 

3.51 

35.1 

1.82 

18.2 

2.84 

28.4 

2.50 

25  0 

2-3 

20-30 

2-3 

20-30 

10-30 

10-25 

10-56 

30-45 

1.1-2.6 

1.5-3.5 

0.9-2.1 

1-2 

0.4-5.1 

4 

1.0-4.2 

1.0-2.2 

0.4-0.9 

Breadth  of  Cells. 


Min., 
Microns. 


6 

9 
14.7 

8 

8 

8 
10 
12 

9 
15 
18 
15 
12 
16 
16 
20 
20 
27 
40 
16 

19.2 
17 

11.9 
20.1 
20 
19 
12 
20 
19 
49 
33 

17 

9 

17 

8 


16 
12 


Max., 
Microns 


15 

15 

16.8 

29 

20 

20 

21 

21 

24 

25 

25 

24 

25 

32 

32 

41 

42 

42 

80 

12.6 

27.9 

27.1 

22 

29.9 

37.8 

29 

42 

44 

33 

92 

50 

25 
14 
24 
29 


21 
20 


Aver., 
Microns. 


15 
13 
16 

16 
16 
15 


16 
20 
20 


50 

25 . 2 
25.9 
18.5 
29.4 
29.9 

38 


15 
20 
12 


21 
20 
17 
16 


DIMENSIONS  OF  FIBER  CELLS 


325 


Vetillard  gives  a  somewhat  similar  table  as  follows: 


Name. 


Linen 

Hemp  {Cannabis  saliva) 

Hop  fiber  {Hiimulus  lupulus) 

Nettle  fiber  ( Urtica  dioica) 

Ramie  (Urtica  nivea) 

Fiber  of  paper  mulberry 

Sunn  hemp  {Crotalaria  juncea) 

Broom-grass  (Sarothamnus  vulgaris) . .  . 
Feather-grass  (Spartium  junceum) .... 

White  clover  {Melilotus  alba) 

Cotton 

Gambo  hemp  (Hibiscus  cannabinus) .  . 

Linden-bast  ( Tilia  europcea) 

Jute  (Corchorus  capsularis) 

Lace  bark  (Lagetta  linlearia) 

Willow  (Salix  alba) 

Esparto 

Lygceum  spartum 

Pineapple  fiber 

SUk-grass  (Bromelia  karatas) 

Wild  pineapple  (Bromelia  pinguin) 

New  Zealand  flax  (Phormium  tenax) . . . 

Yucca  fiber 

Sansevieria  fiber 

Pita  (Agave  americana) 

Manila  hemp  (Musa  textilis) 

Banana  (Musa  paradisaica) 

Date  palm  (Phoenix  dactylifera) 

Talipot  palm  (Corypha  umbraculifera) . 

OU  palm  (Elceis  guineensis) 

Raphia  tcedigera 

Ita  palm  (Mauritia  flexuosa) 

Coir  fiber  (Cocos  nucifera) 


Length,  Mm. 


Min. 


4 
2 
5 
5 
10 
2 

1.2 
1.5 
3 


0.5 

1.3 

3 

2.5 

0.8 

5 

0.5 

1.5 

1.5 

3 


2 

1.5 

1.5 

1.5 

1 

0.4 


Max. 


66 
55 
19 
57 
250 
25 
12 

9 
16 
18 
40 

6 

5 

5 

6 

3 

3.5 

4.5 

9 
10 

2 
15 

6 

6 

4 
12 


6 

5 

3.5 

3 

3 

1 


Mean. 


25 

20 

10 

27 

120 

10 

8 

5 

10 

10 


5 

2 

2 

5 

2 

1.5 

2.5 

5 

5 

2 

9 

4 

3 

2. 

6 

5 

3 

3 

2. 

2. 

1 

0 


Breadth,  Microns. 


Min. 


15 
16 
12 
20 


25 
10 


20 

14 
14 
20 
10 
17 

7 
12 

4 
20 

8 
10 
10 
15 
20 
16 
20 
16 
16 
10 
12 
10 
12 


Max. 


37 
50 
26 
70 
80 


50 
25 


36 

33 
20 
25 
20 
30 
18 
20 
8 
32 
16 
20 
20 
26 
32 
32 
40 
24 
28 
13 
20 
16 
24 


Mean. 


20 
22 
16 
50 
50 
30 
30 
15 
20 
30 

21 
16 

22.5 


22 
12 
15 
6 
24 
13 
16 
15 
20 
24 
24 
28 
20 
24 
11 
16 
12 
20 


Ratio 

of 
Breadth 

to 
Length. 


1200 
1000 
620 
550 
2400 
350 
260 
330 
500 
330 

240 
125 

90 
500 

90 
125 
160 
830 
210 
150 
550 
170 
150 
100 
250 
180 
150 
120 
230 
160 
130 

35 


The  comparative  sizes  of  the  fiber  elements  are  very  variable,  therefore 
the  figures  in  the  last  column  of  the  above  table  should  be  used  as  the  most 
distinctive  characteristic.  Many  conditions  of  growth  and  cultivation 
cause  the  fiber  elements  to  be  longer  or  shorter,  thicker  or  thinner;  also 
in  the  case  of  bast  fibers  their  position  in  the  plant  stalk  introduces  dif- 
ferences in  dimensions.     From  these  considerations  it  follows  that  the 


326  THE  VEGETABLE   FIBERS 

relative  values  for  the  sizes  of  fiber  elements  can  only  be  used  with  proper 
circumspection  and  they  have  no  positive  significance. 

4.  Classification. — Perhaps  the  most  systematic  and  complete  enumera- 
tion of  the  various  vegetable  fibers,  together  with  a  classification  of  their 
technical  uses,  is  that  given  by  Dodge,  from  which  the  following  abstract 
is  taken: 

STRUCTURAL  CLASSIFICATION 

A.  FiBRO VASCULAR  STRUCTURE. 

1.  Bast  Fibers. — Derived  from  the  inner  fibrous  bark  of  dicotyledonous  plants  or 
exogens,  or  outside  growers.  They  are  composed  of  bast-cells,  the  ends  of  which 
overlap  each  other,  so  as  to  form  in  mass  a  filament.  They  occupy  the  phloem  portion 
of  the  fibrovascular  bundles,  and  their  utUity  in  nature  is  to  give  strength  and  flexibility 
to  the  tissue. 

2.  Woody  Fibers. 

(a)  The  stems  and  twigs  of  exogenous  plants,  simply  stripped  of  their  bark  and 
used  entire,  or  separated  into  withes  for  weaving  or  plaiting  into  basketry. 

(b)  The  entire  or  subdivided  roots  of  exogenous  plants,  to  be  employed  for  the 
same  purpose,  or  as  tie  material,  or  as  very  coarse  thread  for  stitching  or  binding. 

(c)  The  wood  of  exogenous  trees  easily  divisible  into  layers  or  splints  for  the  same 
purposes,  or  more  finely  divided  into  thread-like  shavings  for  packing  material. 

(d)  The  wood  of  certain  soft  species  of  exogenous  trees,  after  grinding  and  con- 
verting by  chemical  means  into  wood-pulp,  which  is  simple  cellulose,  and  similar  woods 
more  carefidly  prepared  for  the  manufacture  of  artificial  silk. 

3.  Structural  Fibers. 

(a)  Derived  from  the  structural  system  of  the  stalks,  leaf-stems,  and  leaves,  or 
other  parts  of  monocotyledonous  plants,  or  inside  growers,  occurring  as  isolated 
fibrovascular  bundles,  and  surrounded  by  a  pithy,  spongy,  corky,  or  often  a  soft, 
succulent,  cellular  mass  covered  with  a  thick  epidermis.  They  give  to  the  plant 
rigidity  and  toughness,  thus  enabling  it  to  resist  injury  from  the  elements,  and  they 
also  serve  as  water-vessels. 

(b)  The  whole  stems,  or  roots,  or  leaves,  or  split  and  shredded  leaves  of  mono- 
cotyledonous plants. 

(c)  The  fibrous  portion  of  the  leaves  or  fruits  of  certain  exogenous  plants  when 
deprived  of  their  epidermis  and  soft  cellular  tissue. 

B.  Simple  Cellular  Structure. 

4.  Surface  Fibers. 

(a)  The  down  or  hairs  surrounding  the  seeds,  or  seed  envelopes,  or  exogenous 
plants,  which  are  usually  contained  in  a  husk,  pod,  or  capsule. 

(6)  Hair-like  growths,  or  tomentum,  found  on  the  surfaces  of  stems  and  leaves, 
or  on  the  leaf-buds  of  both  divisions  of  plants. 

(c)  The  fibrous  material  produced  in  the  form  of  epidermal  strips  from  the  leaves 
of  certain  endogenous  species,  as  the  palms. 

5.  Pseudo-fibers,  or  Fcdse  Fibrous  Material. 

(a)  Certain  of  the  mosses,  as  the  species  of  the  Sphagnum,  for  packing  material. 

(b)  Certain  leaves  and  marine  weeds,  the  dried  substance  of  which  forms  a  more 
delicate  packing  material. 

(c)  Seaweeds  wrought  into  lines  and  cordage. 

(d)  Fungus  growths,  or  the  mycelium  of  certain  fungi  that  may  be  appUed  to  eco- 
nomic uses,  for  which  some  of  the  true  fibers  are  employed. 


CLASSIFICATION  327 

The  bast  fibers  are  clearly  defined,  and  all  such  fibers  when  simply 
stripped  are  similar  in  form  as  to  outward  appearance,  differing  chiefly  in 
color,  fineness,  and  strength.  An  example  of  a  fine  bast  fiber  is  the  ribbons 
or  filaments  of  hemp.  I'he  woody  fibers  are  only  fibrous  in  the  broad  sense, 
as  their  cellulose  filaments  are  very  short  and  are  easily  separated  and  all 
extraneous  matter  removed  by  chemical  means,  as  for  the  manufacture 
of  paper-pulp  or  of  artificial  silk.  The  greater  number  of  woody  fibers 
are  merely  wood  in  the  form  of  flexible  slender  twigs  or  osiers  that  are 
useful  for  making  baskets;  or  the  larger  branches  may  be  split  or  sub- 
divided into  strips,  withes,  or  flat  ribbons  of  wood  for  making  coarser 
baskets.  The  softer  woods  still  further  divided  give  the  product  known 
as  "  excelsior,"  which  can  only  claim  a  place  in  the  list  of  fibers  on  account 
of  its  use  in  upholstery  or  packing.  The  structural  fibers  are  found  in 
many  forms  differing  widely  from  each  other,  and  the  sm-face  fibers  are 
still  more  varied  in  form.^ 

Among  the  many  forms  of  the  structm'al  fibers  may  be  enumerated  the 
following :  The  stiff,  white,  or  yellowish  fibers  forming  the  structure  of  all 
fleshy-leaved  or  aloelike  plants,  as  the  century  plant,  the  yuccas,  agave, 
and  pineapple,  or  the  fleshy  trunk  of  the  banana;  the  coarser  bundles  of 
stiff,  fibrous  substance  which  gives  strength  to  the  trunks,  leaf,  stem,  and 
even  the  leaves  of  palms,  such  as  piassave,  derived  from  the  dilated  margins 
of  the  petioles  of  a  palm;  stiff  fibers  extracted  by  maceration  from  the 
bases  of  the  leaf-stems  of  the  cabbage  palmetto,  or  the  shredded  leaves  of 
the  African  fan  palm,  known  as  Crin  vegetal,  rattan  strips  and  fibrous 
material  derived  from  bamboo,  the  corn-stalk,  broom-corn,  and  from  reeds, 
sedges,  and  grasses;  still  other  forms  are  the  coir  fiber  surrounding  the 
fruit  of  the  cocoanut,  the  fiber  from  pine-needles,  and  the  fibrous  mass 
filling  the  sponge  cucumber,  which  is  a  peculiar  example  of  a  structural 
fiber  derived  from  an  exogenous  plant.     Sui'face  fibers  may  consist  of  the 

^  The  following  table  shows  the  miports  into  the  United  States  of  various  raw 
vegetable  fibers  for  the  year  ending  June  30,  1912: 

Pounds.  Value. 

Cotton 109,780,071  $20,217,581 

Flax 21,800,000  3,778,501 

Hemp 10,014,000  1,100,273 

Istle 19,670,000  776,351 

Jute 202,002,000  7,183,385 

Kapok 4,198,000  570,084 

Manila  hemp 137,072,000  8,000,865 

New  Zealand  flax 10,728,000  483,310 

Sisal  grass 228,934,000  11,866,843 

All  other 18,540,000  703,254 

Total 762,738,071  $54,680,447 


328  THE   VEGETABLE   FIBERS 

elongated  hairs  such  as  surround  the  pods  of  the  thistle,  and  known  as 
thistle-down,  or  they  may  be  fibrous  growths  around  seed  clusters,  as  the 
cotton-boll,  the  milk-weed  pod,  etc.,  or  they  may  be  the  leaf  scales  or 
tomentum  found  on  the  under  surface  of  leaves  or  epidermal  strips  of 
palm  leaves,  such  as  raffia. 

Dewey  ^  gives  the  following  economic  classification  of  the  vegetable 
fibers : 

(1)  The  cottons,  with  soft,  lint-like  fiber  |  in.  to  2  ins.  long,  com- 
posed of  single  cells,  borne  on  the  seeds  of  different  species  of  cotton-plants. 

(2)  The  soft  fibers,  or  bast  fibers,  including  flax,  hemp,  and  jute; 
flexible  fibers  of  soft  texture,  10  to  100  ins.  in  length,  composed  of  many 
overlapping  cells  and  contained  in  the  inner  bark  of  the  plants. 

(3)  The  hard,  or  leaf,  fibers,  including  Manila,  sisal,  Mauritius,  New 
Zealand  fibers,  and  istle,  all  having  rather  stiff,  woody  fibers  1  to  10  ft. 
long,  composed  of  numerous  cells  in  bundles,  borne  in  the  tissues  of  the 
leaf  or  leaf-stem. 

ECONOMIC  CLASSIFICATION 

A.  Spinning  Fibers. 

1.  Fabric  Fibers. 

(a)  Fibers  of  the  first  rank  for  spinning  and  weaving  into  fine  and  coarse  textures 
for  wearing  apparel,  domestic  use,  or  house-furnishing  and  decoration,  and  for  awnings, 
sails,  etc.  (The  commercial  forms  are  cotton,  flax,  ramie,  hemp,  pineapple,  and  New 
Zealand  flax.) 

(6)  Fibers  of  the  second  rank,  used  for  burlap  or  gunny,  cotton  bagging,  woven 
mattings,  floor-coverings,  and  other  coarse  uses.  (Commercial  examples  are  coir  and 
jute.) 

2.  Netting  Fibers. 

(a)  Lace  fibers,  which  are  cotton,  flax,  ramie,  agave,  etc. 

(6)  Coarse  netting  fibers,  for  all  forms  of  nets,  and  for  hammocks.  (Commercial 
forms:  Cotton,  flax,  ramie.  New  Zealand  flax,  agave,  etc.) 

3.  Cordage  Fibers. 

(a)  Fine-spun  threads  and  yarns  other  than  for  weaving;  cords,  lines,  and  twines. 
(All  of  the  commercial  fabric  fibers,  sunn,  Mauritius,  and  bowstring  hemps.  New 
Zealand  flax,  coir,  Manila,  sisal  hemps,  pandanus;  ^  the  fish-Unes  made  from  seaweeds.) 

{b)  Ropes  and  cables.  (Chiefly  common  hemp,  sisal,  and  Manila  hemps,  when 
produced  commercially.) 

B.  Tie  Material  (rough  twisted). 

Very  coarse  material,  such  as  stripped  palm-leaves,  the  peeled  bark  of  trees,  and 
other  coarse  growths  used  without  preparation. 

1  Year-Book,  Dept.  Agric,  1903. 

-  The  pandanus  fiber  is  obtained  from  the  leaves  of  the  Pandanus  odoratissimus . 
Under  the  microscope  can  be  recognised  fiber  elements,  vascular  tissue,  and  a  small 
celled  parenchym  with  single  crystals  of  calcium  oxalate.  The  fibers  are  1-4  mm. 
long  and  have  numerous  variant  forms.  They  are  slender,  up  to  20  microns  in  breadth. 
The  thickness  is  very  uneven,  so  that  when  viewed  lengthwise,  the  fiber  appears  thin 
in  some  places  and  thick  in  others  (Hohnel) . 


CLASSIFICATION 


329 


C.  Natural  Texttjre8. 


1.  Tree-hasts,  xoith  Tough  Interlacing  Fibers. 

(a)  Substitutes  for  cloth,  prepared  by  simple  stripping  and  pounding.  Cloth  of  this 
character  has  long  been  used  by  the  natives  of  the  Pacific  Islands  under  the  name  of 
Tappa  or  Kapa.  Other  forms,  such  as  the  Damajagua,  of  Ecuador,  are  used  in  South 
America  as  cloth. 

(b)  Lace-barks,  used  for  cravats,  frills,  ruffles,  etc.,  and  for  whips  and  thongs. 
The  lace-bark  tree  is  the 
Lagetta  lintearia,  and  grows 
principally  in  Jamaica.  The 
fiber  (or  rather  fabric)  is  ob- 
tained from  the  inner  bark, 
occurring  in  concentric  layers 
which  are  easily  detachable, 
and  which  are  suited  to  the 
most  delicate  textiles;  when 
stretched  out  they  form  a 
pentagonal  or  hexagonal  mesh 
very  closely  resembling  lace 
(Fig.  152). 

2.  The  Ribbon  or  Layer 
Basts,  extracted  in  thin, 
smooth-surfaced,  flexible 
strips  or  sheets.  (Cuba  bast 
used  as  millinery  material, 
cigarette  wrappers,  etc.)  The 
Cuba  bast  here  referred  to  is 
the  lace-like  inner  bark  from 
the  Hibiscus  elatus,  which  was 
formerly  largely  used  for  ty- 
ing up  bundles  of  Havana  cigars.  The  plant  also  yields  a  bast  fiber  which  is  coarse 
but  very  strong,  and  is  suitable  for  the  making  of  cordage  and  coffee  bags. 

3.  Inierlncing  Structural  Fiber  or  Sheaths. 

(a)  Pertaining  to  leaves  and  leaf-stems  of  palms,  such  as  the  fibrous  sheaths  found 
at  the  bases  of  the  leaf-stalks  of  the  cocoanut. 

(6)  Pertaining  to  flower-buds.  The  natural  caps  or  hats  derived  from  several 
species  of  palms. 


Fig.  152. — Lace  Bark.     (Herzog.) 


D.  Brush  Fibers. 


1.  Brushes  Manufactured  from  Prepared  Fiber. 

(a)  For  soft  brushes.  (Substitutes  for  animal  bristles,  such  as  Tampico.) 
(6)  For  hard  brushes.  (Examples:  Palmetto  fiber,  palmyra,  kittul,  etc.)  Kittul, 
or  kitool,  fiber  is  obtained  from  the  jaggery  palm,  Caryota  ur'ens.  The  structural  fiber 
is  brownish  black  in  color  and  lustrous,  the  filaments  being  straight  and  smooth. 
It  somewhat  resembles  horsehair  and  curls  like  coir  when  drawn  between  the  thumb 
and  nail  of  the  forefinger.  In  Ceylon  the  fiber  is  used  for  the  manufacture  of  ropes 
of  great  strength  which  are  used  for  tying  elephants.  It  is  largely  used  for  making 
brushes  of  various  kinds,  especially  machine  brushes  for  polishing  linen  and  cotton 
yarns,  and  for  brushing  velvets. 


330  THE  VEGETABLE  FIBERS 

2.  Brooms  and  Whisks. 

(a)  Grass-like  fibers.     (Examples:  Broom-root,  broom-corn/ etc.) 
(6)  Bass  fibers.     (Monkey  bass,  etc.) 

3.  Very  Coarse  Brushes  and  Brooms. 

Material  used  in  street-cleaning.     Usually  twigs  and  splints. 

E.  Plaiting  and  Rough-weaving  Fibers. 

1.  Used  in  Hats,  Sa^idals,  etc. 

(a)  Straw  plaits.  From  wheat,  rye,  barley,  and  rice  straw.  (Tuscan  and  Japanese 
braids.) 

{b)  Plaits  from  split  leaves,  chiefly  palms  and  allied  forms  of  vegetation.  (Panama 
hats.)  The  true  panama  fiber  for  the  making  of  the  hats  that  go  by  that  name  is 
obtained  from  the  Planla  de  Torquilla  or  Carludovica  Palmata,  which  grows  wild 
in  the  swamps  of  tropical  America.  The  leaves  employed  for  the  making  of  the  hats 
are  the  young  ones,  which  are  plucked  before  they  have  fully  expanded.  They  are 
then  boUed  in  water  to  which  a  Uttle  lemon  juice  has  been  added,  and  afterwards 
they  are  hung  up  to  dry  in  an  airy  though  shady  place.  Throughout  the  operations 
of  drying  and  hat  plaiting  the  straw  should  never  be  ex^^osed  to  the  sun,  as  this  would 
cause  the  hat  to  have  a  streaky  appearance  owing  to  the  unequal  bleaching  of  the 
strips.  When  the  leaves  are  nearly  dry  they  are  split  into  very  narrow  strips  of  an 
even  width,  and  are  then  tied  in  bunches  and  left  to  dry.  After  the  plaiting  is  finished 
the  hats  are  cleaned  with  soap  and  lemon  juice,  polished,  and  are  then  ready  for  the 
market. 

(c)  Plaits  from  various  materials.  (Bast  and  thin  woods  used  in  millinery  trim- 
mings.) 

2.  Mats  and  Mattings;   also  Thatch  Materials. 

(a)  Commercial  mattings  from  Eastern  countries.  The  Japanese  floor  mattings 
imported  into  this  country  are  made  either  from  the  rush  known  as  Juncus  effusus 
(the  Bhigo-i  mat  rush),  or  from  the  Cyperus  unitans  (the  Shichito-i  mat  rush),  the 
better  quality  being  made  from  the  first -named  product.  The  Juncus  effusus  is  also 
grown  on  the  Pacific  Coast  of  the  United  States,  as  well  as  a  similar  species  known  as 
J .  robtistus. 

(b)  Sleeping-mats,  screens,  etc. 

(c)  Thatch-roofs,  made  from  tree-basts,  palm-leaves,  grasses,  etc. 

3.  Basketry. 

(a)  Manufactures  from  woody  fiber. 

1  The  fiber  from  broom-grass  {Sarothamnus  mdgaris)  is  a  rather  useful  one  for  paper- 
making.  According  to  Vetillard,  it  shows  the  following  microscopic  characteristics: 
The  bast  fibers  are  2-9  mm.  (mostly  5-6  mm.)  long  and  10-25  microns  (mostly 
15  microns  broad).  The  ratio  of  length  to  breadth  averages  330.  The  fibers  are 
colored  blue  with  iodine  and  sulfuric  acid,  or  violet  or  yellowish;  they  are  short, 
striped,  full,  and  round,  of  small  and  very  uniform  diameter.  The  lumen  looks  like 
a  line.  The  median  layer,  which  is  colored  yellow,  often  stretches  not  beyond  the 
point  of  the  fiber,  which  is  mostly  rounded  off,  lapped  over  or  forked.  The  sections 
lie  in  a  thick  network  of  median  layer,  and  are  small  and  blue  (with  iodine  and  sulfuric 
acid).  Two  different  kinds  of  sections  can  be  distinguished.  The  one  has  a  lumen 
like  a  small  point  or  short  streak  with  or  without  any  contents  (yellow,  granular), 
is  polygonal,  sharp-edged,  with  visible  stratification,  although  not  numerous  yet 
readily  seen;  the  outer  layers  are  often  somewhat  lignified.  The  other  sections,  as 
with  hemp,  are  irregular,  but  smaller,  and  are  not  colored  as  dark  as  the  other  ones; 
the  lumen  is  line-shaped  or  open,  often  having  some  contents. 


CLASSIFICATION  331 

(6)  From  whole  or  split  leaves  or  stems. 

4.  Miscellaneous  Manufactures. 

Willow-ware  in  various  forms;  chair-bottoms,  etc.,  from  splints  or  rushes. 

F.  Various  Forms  of  Filling. 

1.  Stuffing  or  Upholstery. 

(a)  Wadding,  batting,  etc.,  usually  commercially  prepared  lint-cotton. 

(b)  Feather  substitutes  for  filling  cushions,  etc.;  cotton,  seed-hairs,  tomentum 
from  surfaces  of  leaves,  other  soft  fibrous  material. 

(c)  Mattress  and  furniture  filling;  the  tow  or  waste  of  prepared  fiber;  unprepared 
bast,  straw,  and  grasses;  Spanish  moss,  etc. 

2.  Caulking. 

(a)  Filling  the  seams  in  vessels,  etc.;  oakum  from  various  fibers. 

(6)  Filling  the  seams  in  casks,  etc.;  leaves  of  reeds  and  giant  grasses. 

3.  Stiffening. 

In  the  manufacture  of  "staff"  for  building  purposes,  and  as  substitutes  for  cow- 
hair  in  plaster;  New  Zealand  flax;  palmetto  fiber. 

4.  Packing. 

(a)  In  bulkheads,  etc.;  coir,  cellulose  of  corn-pith.  In  machinery,  as  in  valves  of 
steam-engines;  various  soft  fibers. 

(b)  For  protection  in  transportation;  various  fibers  and  soft  grasses;  marine 
weeds;  excelsior. 

G.  Paper  Material. 

1.  Textile  Papers. 

(a)  The  spiiming  fibers  in  the  raw  state;  the  secondary  qualities  or  waste  from 
spinning-mills,  which  may  be  used  for  paper-stock,  including  tow,  jute-butts,  Manila 
rope,  etc. 

(b)  Cotton  or  flax  fiber  that  has  previously  been  spun  and  woven,  but  which,  as 
rags,  finds  use  as  a  paper  material. 

2.  Bast  Papers. 

This  includes  Japanese  papers  from  soft  basts,  such  as  the  paper  mulberry.^ 

^  The  fiber  of  the  Broussonetia  {Moms)  papyrifera  is  used  in  China  and  Japan  for 
the  making  of  paper  and  the  preparation  of  fabrics,  and  in  Europe  for  the  manu- 
facture of  strong  papers.  Hence  it  is  frequently  to  be  found  in  such.  According  to 
Hohnel,  the  fibers  employed  for  paper  are  very  long,  generally  6-15  mm.  and  up  to 
25  mm.  even,  and  at  the  same  time  only  25-35  microns  thick.  Two  kinds  of  fibers 
may  be  distinguished  microscopically,  thick  and  thin.  They  are  partly  thick-walled, 
smooth  or  marked,  with  very  pronounced  joints,  and  often  partly  ribbon-like  and 
flat.  The  lumen  at  first  on  viewing  the  fiber  lengthwise,  is  difficult  to  see,  and  usually 
contains  here  and  there,  near  the  point,  some  yellowish  substance.  In  the  ribbon-hlce 
fibers  the  ends  are  broad  and  rounded-off ;  the  thick-walled  fibers  have  narrower  points 
sometimes  sharp.  The  cross-sections  of  the  fiber  bundles  is  also  naturally  of  two 
kinds.  The  one  consists  of  a  few  very  thick-walled  sections,  polygonal  in  form  with 
blunt  edges  or  inturning  angles,  and  a  rounded-off  contour.  The  other  is  very  large, 
and  at  the  same  time,  consists  of  a  collection  of  many  single  sections  of  small  size, 
and  with  a  rounded-off  or  irregular  form.  All  sections  show  the  pure  cellulose  fiber 
enclosed  in  a  yellowish  median  laj^er  of  network,  which  only  adheres  sUghtly  in  single 
sections;  hence  single  meshes  are  often  free.  The  cross-sections,  when  removed  from 
the  network  of  median  layer,  are  very  similar  to  those  of  cotton,  but  possess  a  fine 
stratified  structure,  which  is  completely  lacking  in  cotton.     The  sections  often  show 


332  THE  VEGETABLE  FIBERS 

3.  Palm  Papers. 

From  the  fibrous  material  of  palms  and  similar  plants.     Palmetto  and  yucca  papers. 

4.  Bamboo  and  Grass  Papers. 

This  includes  all  paper  material  from  grass-like  plants,  including  the  bamboos, 
esparto,  etc. 

5.  Wood-pulp,  or  Celhdose. 

The  wood  of  spruce,  poplar,  and  similar  "paper-pulp"  woods  prepared  by  various 
chemical  and  mechanical  processes. 

Wiesner  gives  the  following  botanical  classification  of  the  more  impor- 
tant vegetable  fibers: 

A.  Vegetable  Hairs. 

1.  Cotton  (seed-hairs  of  Gossypium  sp.). 

2.  Bombax  cotton  (fruit-hairs  of  Bomhacece) . 

3.  Vegetable  silks  (seed-hairs  of  various  AsclepiadacecB  and  Apocynacece) . 

B.  Bast  Fibers  from  the  Stalks  and  Stems  of  Dicotyledonous  Plants. 

(a)  Flax-like  fibers. 

4.  Flax  {Linum  usitatissimum) . 

5.  Hemp  (Cannabis  saliva) . 

6.  Gambo  hemp  (Hibiscus  cannabinus). 

7.  Sunn  hemp  (Crotalaria  juncea) . 
S.  Queensland  hemp  (Sida  retusa). 

9.  Yercum  fiber  (Calotropis  gigantea). 

(b)  Ba;hmeria  fibers. 

10.  Ramie  or  China  grass  (Boehmeria  nivea). 

(c)  Jute-like  fibers. 

11.  Jute  (Cor chorus  capsularis  and  C.  olitorius). 

12.  Raibhenda  (Abelmoschus  tetraphyllos) . 

13.  Pseudo-jute  (Urena  sinuata.) 

(d)  Coarse  bast  fibers. 

14.  Bast  fibers  from  Bauhinia  racemosa.     The  Bauhinia  is  a  genus  of  arborescent 

or  climbing  plants  found  in  tropical  countries.  The  fiber  is  obtained  from 
the  bast  of  the  inner  bark,  and  may  be  made  mto  coarse  cordage,  but  it 
soon  rots  in  water.  The  fiber  is  reddish  in  color  and  tough  and  strong, 
and  has  been  employed  in  India  for  construction  of  bridges. 

15.  Bast  fibers  from  Thespesia  lampas. 

16.  Bast  fibers  from  Cordia  latifolia. 

(e)  Basts. 

17.  Linden  bast  i  (Tilia  sp.). 

portions  of  the  inner  contents.  The  fibers  often  have  adhering  prismatic  crystals  of 
calcium  oxalate.  Lengthwise  the  fibers  often  appear  to  be  enclosed  by  a  thin-walled 
loose  sheath. 

1  The  fibers  of  linden  bast  are  completely  lignified.  They  are  1-5  mm.  (mostly 
2  mm.)  in  length  and  14-20  microns  (mostly  16  microns)  in  breadth.  The  ratio  of 
the  length  to  the  breadth  is  about  125.  Viewed  longitudinally,  the  fiber  appears 
very  short,  thin,  stiff,  and  full.  The  points  are  sharp  or  irregular.  Most  of  the  small 
sections  are  polygonal  with  straight  sides  and  pointed  edges,  and  are  firmly  bound 
together  into  groups  by  a  median  layer  which  gives  a  dark  yellow  color  when  treated 
with  iodine  and  sulfuric  acid.     The  lumen  is  seen  as  a  point,  or  layer. 


CLASSIFICATION  333 

18.  Bast  from  Sterculia  villosa. 

19.  Bast  from  Holoptelea  integrifolia. 

20.  Bast  from  Kydia  cnlycina. 

21.  Bast  from  Lasiosyphon  speciosus. 

22.  Bast  from  Sponia  Wightii. 

C.  Vascular  Bundles  from  Monocotyledonous  Plants. 

(a)  Leaf  fibers. 

23.  Manila  hemp  (Musa  textilis  and  others  of  this  kind). 

24.  Pita  (Agave  arnericana  and  A.  inexicana). 

25.  Sisal  {Agave  rigida). 

26.  Mauritius  hemp  (A  ^afe /ceiida) . 

27.  New  Zealand  flax  {PJiormium  tenax), 

28.  Aloe  fibers  {Aloe  sp.). 

29.  BromeHa  fibers  {Bromelia  sp.). 

30.  Pandanus  fibers  {Pandanus  sp.). 

31.  Sansevieria  fibers  {Sansevieria  sp.). 

32.  Sparto  fibers  {Stipa  tenacissima) . 

33.  Piassave  {Attalea  funifera,  Raphia  vinifera,  etc.).     Piassave  fiber  is  obtained 

from  a  palm-tree,  Attalea  funifera.  It  is  a  structural  fiber  obtained  from 
the  dilated  base  of  the  leaf-stalks.  It  is  stiff,  wiry,  and  bright  chocolate 
in  color,  and  is  principally  used  in  the  manufacture  of  brushes.  It  is 
also  used  on  the  street-sweeping  machines  in  London.  The  palm  grows 
principally  in  Brazil,  where  the  natives  use  the  fiber  for  making  coarse 
cables  which  are  verj'  durable  and  so  light  that  they  will  float  on  water. 
{b)  Stem   fibers. 

34.  TiUandsia  fibers,  southern  moss  {Tillandsia  usneoides). 

(c)  Fruit  fibers. 

35.  Coir  or  cocoanut  fiber  {Cocos  nucifera). 

36.  Peat  fibers. 

(d)  Paper  fibers. 

37.  Straw  fibers  (rye,  wheat,  oat,  rice). 

38.  Esparto  fibers  (leaf  fibers  of  Stipa  tenacissima). 

39.  Bamboo  fibers  {Bambusa  sp.). 

40.  Wood  fiber  (pine,  fir,  aspen,  etc.). 

41.  Bast  fiber  from  paper  mulberry  {Broussonetia  papyrifera). 

42.  Bast  fiber  from  Edgeworthia  papyrifera. 

43.  Peat  fibers. 


Lecomte   (Textiles  vegetaux)   gives  the    following   classification   with 
reference  to  the  botany  of  the  textile  fibers. 

A.  Vegetable  Hairs. 

Cotton. 
Asclepias.    1 

4   .,  ,  .     '    \  Minor  vegetable  hair  fibers. 
EpilobiuTn. 

Typha,  etc. 


334  THE   VEGETABLE   FIBERS 


B.  Bast  Fibers. 


I.  Dicotyledons. 

a.  Urticaceoe  family. 
Hemp  (Cannabis). 
Ramie  (Boehmeria). 
Nettle  iUrtica). 

Paper  mulberry  (Broussonetia) . 
Hop  ^  {Huinulus). 

b.  Ldnacece  family. 

Linen  (Linum). 

c.  Thytneleacea;  family. 

Lace  bark  (Lagetta). 
Nepal  paper  (Daphne). 

d.  Tiliacece  family. 

Jute  (Cor chorus). 
Linden  (Tilia). 

e.  Malvacece  family. ^ 

Queensland  hemp  (Sida). 
Caisar  weed  ( Urena) . 
Pseudo-hemps  (Hibiscus). 

f.  Papilionacece  family. 

Sunn  hemp  (Crotalaria) . 
Clover  (Melilotus). 
Ginestra  (Genista). 
Spanish  sparto  (Spartium). 

g.  Cordiacece  family. 

Cordia  fibers. 
h.  Asclepiadace(B  family. 

Giant  asclepias  (Calotropis). 

1  The  hop  fiber,  which  possesses  an  increasing  importance  in  paper  making,  accord- 
ing to  Hohnel,  consists  of  elements  from  4  to  19  mm.  (mostly  10  mm.)  long,  and  12 
to  26  microns  (mostly  16  microns)  broad.  The  bast  fibers  consist  of  pure  cellulose. 
They  are  uniformly  thick,  and  show  two  kinds  of  forms:  thin,  very  thick-walled  fibers 
with  a  line-like  lumen,  which  is  only  noticeable  when  it  contains  some  matter  inside, 
and  with  long,  tapering,  sharp  points;  also  flat,  ribbon-like  fibers  with  broad,  rounded- 
off  points  and  large  lumen.  In  cross-section,  the  delicate  net-work  of  median  layer 
IS  especially  noticeable,  in  the  yellow  meshes  of  which  the  blue,  small  cross-sections 
(which  are  very  uniform  in  their  dimensions)  are  loosely  enclosed.  Also  isolated 
meshes  are  sometimes  empty.  The  form  of  the  cross-section  has  some  similarity  to 
that  of  hemp,  but  the  lumena  are  almost  always  open  and  filled  with  a  yellowish 
granular  substance.  Also  the  stratifications  in  the  walls  are  less  numerous  and  more 
difficult  to  observe. 

^  A  rather  remarkable  fiber  from  the  Malvaceae  family  is  that  from  Adansonia 
digitata,  or  Monkey  Bread  Tree,  of  Africa.  The  plant  is  one  of  the  largest  trees  in 
the  world  and  is  also  said  to  be  one  of  the  longest  lived.  It  abounds  in  Africa  from 
Senegal  to  Abyssinia.  The  fiber  is  derived  from  the  bark  and  is  strong  and  much 
valued  for  cordage.  In  Africa  it  is  much  used  for  rope,  twine  and  sacking,  and  in 
India  it  is  used  for  making  elephant  saddles.  It  has  also  been  used  in  England  for 
the  manufacture  of  special  kinds  of  paper. 


PHYSICAL  STRUCTURE    OF  SEED-HAIRS  335 

II.  Monocotyledons. 

a.  GramineoE  family. 

Sparto  grass  ^  (Stipa). 
Weeping  sylvan  [Lygeum). 

b.  lAliacece  fanuly. 

New  Zealand  hemp  (Phormium) . 

Yucca  {Yucca  sp.). 

Bowstring  hemps  (Sansevieria) . 

c.  Amaryllidacece  family. 

Sisal  hemps  (Agave). 

d.  Bromeliacece  family. 

Pineapple  (Ananas). 
BromeUa  fibers  (Bromelia). 

e.  MusaceoB  family. 

Manila  hemp  (Musa). 
/.   Naiadacece  family. 

Sea-wrack  (Zostera). 
g.  Paltnce  family. 

Coir  (Cocos). 

Raffia  (Raphia). 

MmTjmuru  palm  (Astrocaryum) . 

Grin  vegetal  (Chamcerops) . 

Rattan  cane  (Calainus). 

Sago-palm  (Arenga). 

Date-palm  (Phoenix). 

Talipot  palm  (Corypha). 

Oil-palm  (Elceis). 

5.  Physical  Structure  of  Seed-hairs. — The  seed-hairs  or  plumose  fibers, 
are  divided  into  three  morphological  classes : 

(1)  Those  consisting  of  single  cells,  one  end  of  which  is  closed  and 
tapers  to  a  point,  the  other  end  being  broken  off  abruptly  where  it  is  torn 
from  the  seed  to  which  it  was  fastened  during  growth.     This  class  includes 

'  The  fibers  obtained  from  the  leaves  of  both  the  grasses  Slipa  tenacissima  and 
Ligacium  Spartum  are  known  as  Alfa  fiber;  it  is  also  known  by  the  name  Esparto. 
It  is  especially  employed  in  paper.  The  fibers  of  Stipa  tenacissima  are  0.5  to  3.5  mm. 
long  and  7  to  18  microns  broad.  Those  of  Lagaciutn  Spartum  have  a  length  of  1.3 
to  4.5  mm.  and  a  breadth  of  12  to  20  microns.  When  viewed  lengthwise  both  fibers 
are  short,  thin,  full,  lustrous,  and  of  very  uniform  diameter.  The  lumen  is  seen  as 
a  fine  line,  and  often  contains  a  yellowish  substance.  The  ends  are  tapering,  and 
either  somewhat  rounded  off  or  cut  off  obliquely.  Most  of  the  fibers  are  not  lignified, 
although  many  are  colored  yellow  with  iodine  and  sulfuric  acid.  The  cross-sections 
treated  with  the.se  reagents  appear  partly  yellow  and  partly  blue.  The  innermost 
layers  of  the  wall  are  nearly  always  unlignified,  and  on  the  other  hand,  the  outer  layers 
are  alwaj's  lignified.  The  form  of  the  cross-sections  is  rounded.  Apart  from  the 
fiber  itself,  in  its  microscopical  examination,  the  web  of  cuticle  is  especially  prominent. 
This  consists  of  epidermal  cells,  fissure  cells,  and  hairs,  the  last  often  being  bent  in 
the  form  of  a  hook.  The  web  of  cuticle  has  toothed  side  walls  which  are  very 
remarkable.  They  are  strongly  silicified,  and  the  sihcious  skeletons  are  easily  recog- 
nised in  the  ash. 


Asclepideoe. 
\  Apocynece. 


336  THE   VEGETABLE   FIBERS 

the  most  important  plmnose  fibers,  such  as  cotton  and  the  vegetable 
silks. 

(2)  Those  consisting  of  a  series  of  cells  joined  together  to  form  a 
continuous  fiber;  this  class  includes  the  tomentum  or  epidermal  hair 
obtained  from  certain  ferns;  these  are  practically  valueless  as  textile 
materials,  though  employed  for  upholstery  and  similar  uses. 

(3)  Those  consisting  of  several  series  of  cells,  represented  by  the  fibers 
of  the  so-called  cotton-grass  and  elephant-grass. 

The  hair  fibers  may  originate  on  almost  any  organ  of  the  plant  exposed 
to  the  air.  The  following  table  indicates  the  origin  of  the  majority  of 
such  fibers: 

Hair  Fibers 

(1)  Covering  the  seeds,  either  entirely  or  in  part' 
Cotton MalvaceuB. 

Marsdenia 

Calotropis 

Asdepias 

Vincetoxicum 

Beaumontia 

Strophantus      ) 

Epilobium .  .  .Q^notheraceoe. 

(2)  Contained  in  the  flower  (rudimentary  floral  envelope) : 
Typha Typhaceoe. 

Eriophorum .  .  .  .Cyperacece. 

(3)  Lining  the  interior  of  the  fruit: 
Ochroma  \ 

Bombax  i  Bombacece. 

Eriodendron     j 

(4)  Covering  stalks  and  leaves: 
Cibotium Ferns. 

The  cell-wall  of  the  plumose  fibers  in  some  cases  is  relatively  thin, 
while  in  others  it  is  comparatively  thick.  It  is  generally  without  apparent 
structure,  though  sometimes  it  Is  seen  to  contain  pores,  and  occasionally 
a  meshlike  interlacing  of  filaments  is  observable,  especially  at  the  base  of 
the  fiber.  The  inner  surface  of  the  cell-wall  is  usually  coated  with  a 
cuticle  of  dried  protoplasm,  which  is  evidently  similar  in  constitution 
to  the  outer  cuticle,  as  it  also  remains  undissolved  when  the  fiber  is  dis- 
solved in  either  concentrated  sulfuric  acid  or  an  ammoniacal  solution  of 
copper  oxide.  Lecomte  gives  the  following  classification  of  vegetable 
fibers  with  respect  to  their  cellular  structure: 

1.  Fiber  consisting  of  a  single  isolated  cell:  Cotton;  Asdepias  silk;  Bombax  cotton. 

2.  Single  fibers  associated  in   bundles:    Unbleached  jute;    Linen    (poorly  prepared 

linen  frequently  contains    parenchymous  cells  and  epidermal  cells);   Ambari 
hemp  {Hibiscus);  Ramie;  Hemp  (well  prepared). 


PHYSICAL  STRUCTURE  OF  BAST  FIBERS  337 

S.  Fibers  with  medullary  cells:     Queensland  hemp  {Sida  retusa);     Cordia  latifolia; 

Thespesia  lam  pas. 
4.  Fibers  with  parenchymous  cells:    Abelmoschus  tetraphyllos;    Urena  sinuata;   Sunn 

hemp  (Crotalaria  juncea) ;   Calotropis  gigantea;  Hemp  (as  often  prepared) . 

6.  Physical  Structure  of  Bast  Fibers. — The  general  term  of  bast  fiber 
includes  really  two  distinct  forms;  if  the  fiber  occurs  in  the  bast  itself 
it  should  be  designated  as  true  hast  fiber,  such  as  linen,  hemp,  and  jute. 
When,  however,  the  fibers  do  not  occur  in  the  bast,  but  in  single  bundles 
in  the  leaf  structure  of  the  plant,  they  should  be  designated  as  sclerenchy- 
mous  fibers.  In  true  bast  fibers  there  are  seldom  to  be  noticed  distinct 
pores,  whereas  the  sclerenchymous  fibers  are  abundantly  supplied  with 
them.  On  the  other  hand,  however,  the  true  bast  fibers  frequently  show 
peculiar  dislocations  or  joints  caused  by  an  unequal  cell  pressure  in  the 
growing  plant;  these  are  entirely  absent  in  the  sclerenchymous  fibers. 
The  ends  of  all  bast  fibers  are  usually  quite  characteristic  and  exhibit  a 
wide  diversity  of  forms;  at  times  they  are  sharp-pointed  and  again  blunt; 
some  possess  but  a  single  point,  while  others  are  split  or  forked;  some- 
times the  cell-wall  is  thicker  than  in  the  rest  of  the  fiber,  and  sometimes 
it  is  thinner.  When  the  cells  occur  in  bundles  they  are  frequently  separated 
from  one  another  by  a  so-called  median  layer,  which  forms  a  sort  of  matrix 
in  which  the  separate  filaments  are  imbedded.  This  layer  usually  differs 
in  its  chemical  composition  from  the  cell-wall  proper,  and  gives  different 
color  reactions  with  various  reagents,  as  it  generally  consists  of  lignified 
tissue.  In  many  cases  the  well-walls  appear  to  have  a  distinct  structure, 
being  composed  of  concentric  layers  which  in  cross-section  exhibit  a 
stratified  appearance. 

The  bast  fibers  may  be  roughly  divided  into  four  classes  with  reference 
to  the  comparative  sizes  of  the  cell-wall  and  the  inner  canal  or  lumen: 

(1)  The  canal  takes  up  about  four-fifths  of  the  diameter  of  the  fiber:   Ramie  and 

China-grass. 

(2)  The  canal  is  about  two-thirds  of  the  diameter  of  the  fiber:  Pineapple  fiber; 

Hemp;   Pita  and  sunn  hemp. 

(3)  The  canal  is  mostly  less  than  one-half  the  diameter  of  the  fiber:    Ambari  hemp 

(Hibiscus);   Yucca;  New  Zealand  hemp  (P/ionnium  ^eriax) ;    Manila  hemp. 

(4)  The  canal  is  often  reduced  to  a  mere  Une:   Linen. 

The  inner  canal  is  very  regular  (and  consequently  the  cell-wall  will 
be  of  uniform  thickness)  in  fibers  of  yucca,  New  Zealand  hemp,  sunn 
hemp,  pita  hemp,  linen,  ramie,  and  the  plumose  fibers.  On  the  other 
hand,  the  canal  is  irregular  (with  resulting  irregularities  in  the  thickness 
of  the  cell-wall)  in  fibers  of  jute,  coir,  Urena  sinuata,  Abelmoschus,  etc. 

All  plant-cell  membranes  are  doubly  refractive  tow^ard  light,  and  this 
is  especially  true  of  thick-walled  cells  which  are  parallel  to  the  fiber  proper. 


338  THE   VEGETABLE   FIBERS 

If  such  a  fiber  is  examined  in  the  dark  field  of  a  micro-polariscope  it  shows 
a  beautiful  arrangement  of  bright  prismatic  colors. 

The  degree  of  double  refraction  varies  with  different  fibers;  in  some, 
as  for  example  in  coir,  it  is  very  weak,  while  in  others,  such  as  linen  and 
hemp,  it  is  very  strong.  The  following  table  gives  the  polarisation  colors 
shown  by  various  fibers: 


Fiber.  Polarisation  of  Colors. 

Vascular  and  parenchymous  cells  of 


I  Dark  gray, 
wood  and  straw J 

Epidermal  cells  of  straw  and  esparto     Dark  gray. 

Coir Dark  gray. 

Dark  gray  to  light  gray;    also  white  to 


Cotton ,  „ 

I      yellow 

New  Zealand  flax Ditto. 

.^.,          „      ,  .   ,          ,            ,  f  Dark    gray    to    light    grav;     yellowish    to 

Fiber  cells  of  jute  and  esparto {  i 

-^  „      r  r,  ,1  ( White,  j^ellowish,  orange,  red,  violet,  chang- 

Bast  cells  of  flax  and  hemp <      .       ,        „      .  ,      ,  .,         j     •  ,  . 

l     mg  to  yellowish  white  and  violet. 


It  is  difficult  to  formulate  many  sharp  distinctions  between  the  bast 
fibers,  for,  as  a  class,  they  exhibit  many  points  of  similarity.  There 
is  frequently  to  be  observed,  for  example,  almost  as  many  divergences 
from  a  supposedly  normal  type  among  the  individual  fibers  if  any  one 
kind  as  between  the  fibers  of  different  kinds.  That  is  to  say,  in  a  sample 
of  linen,  while  the  general  appearance  would  indicate  that  the  lumen  or 
inner  canal  of  the  fiber  was  relatively  narrow,  yet  in  some  of  the  fibers 
the  lumen  may  appear  quite  broad;  and  in  a  sample  of  hemp  where  the 
general  appearance  of  the  lumen  is  quite  broad,  there  may  be  a  number  of 
fibers  exhibiting  very  narrow  lumens.  The  same  comments  are  also  true 
of  most  of  the  other  general  characteristics  of  the  bast  fibers.  The 
appearance  and  form  of  the  ends  of  the  cells  may  pass  through  all  manner 
of  variations  from  pointed  to  blunt  or  even  forked  in  the  same  sample  of 
any  one  of  the  bast  fibers,  so  it  is  generally  useless  to  draw  any  conclusions 
as  to  identity  from  the  appearance  of  the  fiber  ends  alone.  The  joint- 
like structure  of  some  of  the  bast  fibers  offers  a  somewhat  better  means  of 
discrimination,  though  even  here  it  is  not  safe  to  make  too  broad  generalisa- 
tions. Linen  fibers  very  frequently  exhibit  these  joint  marks,  yet 
there  may  be  found  numerous  linen  fibers  with  no  appearance  of  joints 
at  all. 

7.  Microscopical  Characteristics  of  Vegetable  Fibers. — The  following 
table  gives  the  characteristics  of  the  common  vegetable  fibers  used  in  the 
textile  and  paper  industries : 


MICROSCOPICAL  CHARACTERISTICS  OF  VEGETABLE  FIBERS     339 


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340 


THE   VEGETABLE   FIBERS 


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MICROSCOPICAL  CHARACTERISTICS   OF   VEGETABLE   FIBERS     341 


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342 


THE  VEGETABLE  FIBERS 


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ELASTICITY 


343 


8.  Physical  Properties;  Color. — The  vegetable  fibers  in  the  raw  state 
vary  considerably  in  color;  some,  like  cotton,  ramie,  and  the  vegetable 
silks,  are  almost  pure  white.  Others,  like  linen,  possess  a  grayish  brown 
color;  while  still  others,  like  jute  and  hemp,  have  a  decided  brown  color. 
These  colors,  however,  are  due  to  incrusting  impurities,  as  the  cellulose 
fibers,  purified  and  freed  from  all  such  foreign  matters,  are  always  white. 

9.  Luster. — The  vegetable  fibers  are  usually  less  lustrous  than  those 
of  animal  origin,  and  especially  silk,  though  they  differ  much  in  this  respect. 
Cotton  probably  has  the  least  luster  of 

any,  as  its  surface  is  by  no  means 
smooth  and  even,  but  presents  a  wrinkled 
and  creased  appearance,  hence  scatters 
the  rays  of  light  reflected  therefrom. 
Other  plumose  fibers,  such  as  the  vari- 
ous vegetable  silks,  have  a  very  smooth 
surface,  and  consesequently  exhibit  con- 
siderable luster.  Linen,  jute,  ramie,  and 
the  bast  fibers  in  general,  when  sepa- 
rated into  their  fine  filaments  and 
properly  freed  from  all  incrusting  mat- 
ter, possess  a  rather  high  degree  of 
luster,  for  though  they  have  more  or 
less  roughened  places  and  irregularities 
on  their  surface,  the  major  portion  of 
such  surface  is  smooth  and  regular. 

10.  Elasticity. — The  more  closely  the 
fiber  approximates  to  pure  cellulose  the 
greater  becomes  its  flexibility  and  elas- 
ticity, and  the  more  it  is  lignified,  that 
is  to  say,  the  more  it  is  changed  into 
woody  tissue,  the  less  these  qualities 
become.  That  is  to  say,  the  highly 
lignified  fibers  are  stiff  and  brittle  and 
but  little  adapted  to  the  spinning  of  fine 
yarns. 

An  apparatus  for  testing  the  elastic 
properties  of  yarns  and  automatically  recording  the  load  and  stretch  is 
described  by  J.  A.  Matthew  ^  and  is  shown  in  Fig.  153.  Matthew 
studied  the  relations  of  total  and  permanent  stretch  in  various  yarns 
and  found  an  approximate  constancy  of  the  ratio  of  total  stretch  (  Yt) 
to  permanent  stretch  (  Yp)  in  the  case  of  flax  yarns  and  hemp,  but 
with  both  gray  and  bleached  cotton  the  ratio  was  found  to  decrease  as 
'  Jour.  Text.  Inst.,  1922,  p.  45. 


Fig.  153. — Apparatus  for  Testing  the 
Elasticity  of  Yarns. 


344 


THE  VEGETABLE  FIBERS 


the  breaking  point  was  approached.     The  following  table  gives  the  mean 
values  of  these  ratios : 

VALUES  OF  YilYy 


Load  Applied 
Before 

Cotton  lO's,  American. 

Flax  30's  lea. 

Hemp, 

Unloading, 
Ounces. 

Gray. 

Bleached. 

Green. 

BoUed. 

Bleached. 

25's  lea. 

2 

6 

10 

14 

18 
22 
26 

1.6 

1.49 

1.36 

1.81 
1.64 
1.50 
1.42 
1.38 
1.34 

1.72 
1.69 
1.69 
1.70 
1.72 

1.54 
1.53 
1.55 
1.56 
1.58 

1.53 
1.47 
1.48 
1.50 
1.50 

1.62 
1.59 
1.59 
1.60 
1.58 
1.58 

Average 

1.7 

1.55 

1.5 

1.59 

11.  Tensile  Strength. — In  tensile  strength  the  vegetable  fibers  vary 
considerably;  owing  to  the  great  difference  in  the  physical  form  and 
thickness  of  the  various  fibers,  it  is  difficult  to  give  a  comparison  of  their 
respective  strengths.  The  following  table  gives  a  comparison  between  the 
more  important  fibers: 


Fiber. 


Cotton 

Linen 

Jute 

Hemp 

Coir 

Manila  hemp 
China-grass . . 
Raw  silk .  .  .  . 


Breaking 

Length  in 

Kilometers. 


Tensile  Strength, 

Kilograms  per 

Square  Millimeter. 


34.27 
36.00 
49.51 
78.00 


40.04 


12.  Hygroscopic  Properties. — Tne  hygroscopic  moisture  contained  in 
vegetable  fibers  is  considerably  lower  than  that  present  in  either  wool  or 
silk.  While  the  latter  fibers  under  normal  atmospheric  conditions  will 
average  as  much  as  12  to  16  percent  of  moisture,  cotton,  and  linen  will 
have  only  from  6  to  8  percent.  The  following  table  (after  Wiesner) 
gives  the  amount  of  moisture  in  various  vegetable  fibers  in  the  ordinary 
air-dry  condition,  and  also  the  greatest  amount  they  will  absorb 
hygroscopically. 


HYGROSCOPIC  PROPERTIES 
Hygroscopic  Moisture  in  Vegetable  Fibers. 


345 


Fiber. 


Cotton 

Flax  (Belgian) 

Jute 

China-grass 

Manila  hemp 

Sunn  hemp 

Hibiscus  mnnabinus.  .  .  . 
Abelmoschus  tetraphyllos . 

Esparto 

Urena  sinuata 

Piassave 

Sida  retusa 

Aloe  perfoliaia 

Bromelia  karaias 

Thespesia  lampas 

Cordia  latifolia 

Bauhinia  racemosa 

TUlandsia  fiber 

Pita 

Calotropis  gigantea  (bast) 


Maximum 

Air-dry 

Amount 

Condition. 

Hygroscopic 

Percent. 

Water. 

Percent. 

6.66 

20.99 

5.70 

13.90 

6.00 

23.30 

6.52 

18.15 

12.50 

50.00 

5.31 

10.87 

7.38 

14.61 

6.80 

13.00 

6.95 

13.32 

7.02 

15.20 

9.26 

16.98 

7.49 

17.11 

6.95 

18.03 

6.82 

18.19 

10.83 

18.19 

8.93 

18.22 

7.84 

19.12 

9.00 

20.50 

12.30 

30.00 

5.67 

13.13 

According  to  Scheurer  ^  each  kind  of  fiber  possesses  a  definite  capacity 
of  absorption  when  exposed  to  the  action  of  steam  under  constant  condi- 
tions. When  equihbrium  had  become  estabhshed  he  obtained  the  following 
results : 

Fiber.  Percentage  Moisture. 

Cotton 23 . 0 

Raw  linen 27 . 7 

Raw  jute 28.4 

Bleached  silk 36 . 5 

Bleached  and  mordanted  wool 50. 0 

Hohnel  has  made  some  very  interesting  microscopical  investigations 
on  the  effect  of  moisture  on  the  dimensions  of  fibers;  his  results  may  be 
summarised  as  follows: 

1.  Every  fiber  becomes  thicker  on  moistening  with  water,  whether  the  fiber  is 
twisted  or  not.  Plant  fibers  differ  from  animal  fibers  in  their  behavior,  hi  that  they 
swell    up  more    rapidly   and    to    a   greater  degree.     Animal  fibers    when    moistened 

1  Bull.  Soc.  Ind.  Mulhouse,  1900  p.  89 


346  THE  VEGETABLE  FIBERS 

become  10  to  14  percent  thicker;  for  instance,  human  hair  10.67  percent,  angora 
wool  10.2  percent,  white  alpaca  wool  13.7  percent,  tussur  silk  11  percent.  Only  those 
hairs  which  possess  a  large  medulla  swell  to  any  extent,  since  the  medullary  cells  are 
most  strongly  distended,  for  instance,  cow-hair  gives  16  percent.  The  thickening  of 
plant  fibers  amounts  generally  to  20  percent  or  more.  Thus  New  Zealand  flax  gave 
for  three  determinations  19.5,  20.0,  and  22.3  percent;  aloe  hemp  25.8  percent,  linen 
17.1  percent,  29.0,  21.1  percent,  hemp  21.1,  25.2,  21.0  percent,  cotton  27.5  per- 
cent, etc. 

2.  A  fiber  may  be  either  lengthened  or  shortened  by  moistening,  or  retain  its 
original  length.  The  same  can  also  be  brought  about  by  drying.  It  all  depends 
on  the  condition  in  which  the  fiber  occurs,  and  this  is  governed  by  the  treatment  to 
which  the  fiber  has  been  previously  subjected. 

3.  The  alteration  in  length  in  the  case  of  vegetable  fibers  fluctuates  between 
0.05-0.10  percent,  and  with  animal  fibers  between  0.50-1.00  percent. 

4.  If  one  and  the  same  part  of  a  thread  is  repeatedly  moistened  and  dried,  it  gives 
the  following  results: 

(a)  A  naturally  untwisted  fiber  of  flax,  hemp,  aloe,  China-grass,  cotton,  and 
Manila  hemp  become  lengthened  on  moistening  and  correspondingly  shortened 
(namely  0.05-0.10  percent)  on  drying  in  the  air. 

(h)  New  Zealand  flax  of  trade  behaved  itself  in  just  the  reverse  manner. 

(c)  The  majority  of  the  vegetable  fibers  show  the  peculiarity  of  attaining  the 
greatest  length  on  moistening  with  the  breadth,  when  they  are  wetted  with  water 
they  are  shortened  about  0.01-0.03  percent.  Therefore,  when  a  wet  fiber  is  dried, 
it  at  first  becomes  longer  and  then  rapidly  shortens. 

(d)  When  a  wet  vegetable  fiber  is  strongly  stretched  and  is  allowed  to  dry  in  this 
condition,  it  shows  subsequently  either  (1)  in  case  of  wetting  of  or  of  drying  an  actual 
shortening  of  0.05-0.10  percent  (raw  China-grass)  or  (2)  there  occurs  at  first  a  shorten- 
ing (by  wetting  and  drying),  while  later  the  fiber  acts  in  a  manner  similar  to  New 
Zealand  flax,  consequently  shortening  itself  on  being  moistened  with  the  breadth; 
or  finally  (3)  the  fiber  shortens  itself  at  first,  and  then  like  an  ordinary  fiber,  becomes 
lengthened  (Manila  hemp). 

(e)  All  strongly  twisted  fibers  show  the  peculiarity  of  lengthening  on  drying  and 
shortening  on  wetting.     In  this  case  the  actual  shortening  in  the  beginning  is  important. 

(/)  Any  natural  animal  fiber  is  always  lengthened  by  wetting  and  shortened  by 
drying,  both  values  being  about  0.5-1.0  percent. 

(g)  Any  single  strongly  twisted  animal  fiber  at  first  shows  a  shortening  of  1-2 
percent,  and  then  behaves  just  like  an  untwisted  fiber,  only  the  values  are  much  less. 

(h)  A  stretched  dried  animal  fiber  is  shortened  on  being  wet  for  the  first  time 
(generally  about  one  percent),  and  subsequently  behaves  like  one  which  had  not  been 
stretched. 

It  may  be  seen  from  these  results  of  microscopic  investigation  that  the 
behavior  of  the  fibers  on  swelhng  in  water  is  very  remarkable  and  dis- 
tinctive, and  that  in  this  particular  very  essential  differences  exist  between 
vegetable  and  animal  fibers. 

This  investigation  helps  to  explain  the  fact  why  ropes  shorten  when 
left  in  water.  Fibers  which  are  not  stretched  or  are  only  slightly  so,  are 
arranged  in  ropes  in  permanently  fixed  spirals.  Since  the  fibers  can  only 
be  lengthened  but  slightly,  or  not  at  all,  while  they  are  thickened  20-25 
percent  by  swelling,  the  rope  as  well  as  the  single  twisted  fibers  must 


CHEMICAL  COMPOSITION  AND  PROPERTIES  347 

become  shortened.  If  the  spiral  fibers  are  very  elastic,  as  is  the  case  of 
the  animal  fibers  which  may  be  stretched  5  to  36  percent  in  the  moist 
condition  without  breaking,  then  the  cylinder  composed  of  them  will 
shorten  but  slightly  on  swelling  (or  even  none  at  all),  because  the  spirals 
are  capable  of  being  lengthened.  Thus  it  has  been  observed  that  a  hemp 
rope  will  shorten  8  to  10  percent,  whereas  a  silk  rope  will  shorten  only 
0.24  to  0.95  percent.  Furthermore,  a  twisted  single  vegetable  fiber  will 
shorten  only  slightly,  whereas  it  is  easy  to  understand  that  a  twisted 
single  animal  fiber  will  perhaps  become  lengthened,  while  a  silk  cord  is 
shortened. 

13.  Chemical  Composition  and  Properties. — Although  cellulose  forms 
the  chief  constituent  of  all  vegetable  fibers,  it  varies  much  in  its  purity 
and  associated  products  in  its  occurrence  in  the  various  fibers.  Seed-hairs, 
like  cotton,  consist  almost  entirely  of  cellulose  in  a  rather  pure  state, 
but  the  bast  and  vascular  fibers  alwa3''s  contain  more  or  less  alteration 
products  of  cellulose,  chief  among  which  is  ligno-cellulose,  or  lignin; 
in  fact  jute  is  almost  entirely  composed  of  this  latter  substance.  Seed- 
hairs  mostly  consist  of  one  single  cell  to  the  individual  fiber  and  have 
very  little  foreign  or  incrusting  material  present.  The  other  fibers  are 
made  up  of  an  aggregation  of  cells  bound  together  in  a  compact  form,  and 
in  the  cell  interstices,  there  is  always  present  more  or  less  gummy  and 
resinous  matter,  oils,  mineral  matter,  and  lignified  tissue. 

All  vegetable  fibers  appear  to  contain  more  or  less  pigment  matter, 
usually  of  a  slight  yellowish  or  brownish  color.  In  ordinary  cotton  and 
ramie  this  coloring  matter  occurs  in  only  a  very  small  amount  and  the 
natural  fiber  is  quite  white  in  appearance.  There  are  some  varieties  of 
cotton,  however,  which  are  distinctly  brown  in  color.  Flax,  jute,  hemp, 
etc.,  contain  a  considerable  amount  of  pigment  and  are  of  a  more  or  less 
pronounced  brownish  color. 

In  their  chemical  composition  vegetable  fibers  consist  of  three  parts, 
cell  tissue  (cellulose),  woody  tissue  (lignin),  and  cork  tissue  (cutose).  The 
first  is  the  basic  ingredient  of  all  plant  membranes.  The  following  are  the 
distinguishing  reactions  of  these  three  tissues: 

1.  Pure  cell  tissue  is  recognised  by  giving  blue  colorations  with  clilor-iodide  of 
zinc  and  iodine-sulfuric  acid  reagent.  It  is  soluble  in  ammoniacal  copper  oxide  and 
in  concentrated  sulfuric  acid  without  a  brown  coloration. 

2.  Woody  tissue  gives  a  yellow  coloration  with  chlor-iodide  of  zinc  and  also  with 
aniline  sulfate,  while  with  phloroglucinol  reagent  it  gives  a  red  coloration.  It  is 
soluble  in  concentrated  sulfuric  acid  with  a  strong  brown  coloration,  but  is  insoluble 
in  ammoniacal  copper  oxide  solution. 

3.  Cork  tissue  also  gives  a  yellow  coloration  with  chlor-iodide  of  zinc,  but  beyond 
this  shows  no  especially  characteristic  reaction.  It  is  insoluble  in  both  ammoniacal 
copper  oxide  and  concentrated  sulfuric  acid.  It  is  somewhat  soluble,  however,  in 
boiling  caustic  potash  solution. 


348  THE  VEGETABLE  FIBERS 

Both  the  woody  tissue  and  the  cork  tissue  may  be  removed  from  the 
cell  membrane  proper  by  treatment  with  suitable  chemical  reagents, 
without  destroying  the  form  of  the  fibrous  elements.  Boiling  with 
Schulze's  reagent  (nitric  acid  and  potassium  chlorate)  will  cause  the 
decomposition  of  vegetable  membranes  into  their  fiber  elements  while  still 
preserving  the  original  form  of  the  fiber.  The  same  decomposition  occurs 
in  the  technical  preparation  of  wood-pulp,  where  the  wood  is  boiled  with 
dilute  alkali  or  sulfurous  acid  under  high  pressure. 

Besides  cellulose  and  lignin,  there  is  also  present,  especially  in  seed- 
hairs,  a  cutose  membrane  (cork  tissue)  in  the  form  of  an  external  cuticle. 
Cutose  is  insoluble  in  concentrated  sulfuric  acid,  but  is  slightly  soluble 
in  boiling  caustic  potash.  It  doubtless  originates  from  the  plant-wax 
which  is  imbedded  in  the  cell. 

Albuminous  matter  also  occurs  in  the  fiber  elements,  mostly  as  a  dried 
tissue  which  fills  the  lumen  of  the  fiber  more  or  less  completely.  It  also 
occurs  as  a  thin  film  which  coats  the  inner  wall  of  the  cell  and  remains 
undissolved  when  the  fiber  is  treated  with  concentrated  sulfuric  acid. 
This  membrane  exhibits  all  the  reactions  of  albumen.  Silicic  acid  some- 
times is  present  in  vegetable  fibers,  but  only  in  the  walls  of  the  stegmata 
and  in  epidermal  cells.  On  ignition  the  silicious  matter  is  left  in  almost 
its  original  form.  The  silicious  skeleton  is  insoluble  in  hydrochloric  acid, 
whereas  the  rest  of  the  ash  is  readily  dissolved  by  this  reagent.  Many 
fibers  derived  from  monocotyledonous  plants  exhibit  under  the  microscope 
characteristic  fragments  of  mineral  matter  known  as  stegmata.  These  are 
generally  crystalline  in  structure  and  consist  of  calcium  oxalate,  although 
amorphous  particles  of  silicious  matter  are  also  to  be  noticed  at  times. 
These  silicious  particles  often  occur  in  the  form  of  a  string  of  beads,  a 
form  which  persists  even  after  the  fiber  has  been  reduced  to  an  ash  by 
Ignition.  The  silicious  skeletons  may  also  be  observed  when  the  cellulose 
of  the  fiber  has  been  destroj'ed  by  treatment  with  chromic  acid.  Steg- 
mata are  especially  to  be  observed  in  coir  (cocoanut  fiber),  Manila  hemp, 
and  piassava  fiber.  Crystals  of  calcium  oxalate  occasionally  occur  in  some 
fibers;  they  are  insoluble  in  acetic  but  dissolve  in  hydrochloric  acid. 
On  ignition  of  the  fibers  these  crystals  are  converted  into  calcium  carbonate 
without  much  change  of  form,  and  then  are  soluble  in  even  very  dilute 
acids. 

Woody  fiber  is  to  be  found  in  many  vegetable  fibers,  and  its  presence 
always  lowers  the  economic  value  of  the  fiber.  The  presence  of  woody 
fiber  may  readily  be  determined  by  the  application  of  a  number  of  char- 
acteristic chemical  tests.  Aniline  sulfate,  for  instance,  with  woodsy  fiber 
gives  a  golden  yellow  color;  phloroglucinol  with  hydrochloric  acid  gives 
a  red  color,  phenol  with  hydrochloric  acid  a  gi-een  color,  as  does  also  indol 
with  hydrochloric  acid,  and  a  solution  of  chlor-iodide  of  zinc  gives  a 


LIGNIN  349 

brownish  yellow  color.  Woody  fiber  is  also  destroyed  by  the  action  of 
alkalies  and  hypochlorites  in  the  bleaching  process;  and  in  fact  this 
process  usually  has  for  its  chief  object  the  decomposition  and  removal 
of  the  woody  fiber  which  may  be  present.  Due  to  this  fact,  certain 
bleached  fibers,  such  as  jute  and  hemp,  may  no  longer  exhibit  the  above- 
mentioned  color  reactions,  although  they  may  have  done  so  originally 
in  the  raw  condition. 

There  are  several  reagents  which  are  serviceable  in  micro-chemical 
tests  on  vegetable  fibers,  as  they  yield  distinctive  color  reactions.  With  the 
iodine-sulf uric  acid  reagent  the  principal  fibers  give  the  following  reactions : 

(a)  Blue  Colors: 
Cotton. 

Raw  fiber  from  Hibiscus  cannabinus. 
"        "        "     Calotrojns  gigantea  {greenish  blue  to  blue). 
' '     flax  fiber. 
Cottonised  ramie. 

Raw  sunn  hemp  (often  copper-red) . 
' '     hemp  (greenish  blue  to  pure  blue) . 
(6)  Yellow  to  Brown  Colors: 
Bombax  cotton. 

Vegetable  silk  (occasionally  greenish  or  greenish  blue). 
Raw  jute. 

fiber  of  Ahelmosckus  tetraphyllos . 
"       Urena  sinuata. 

"       Bauhinia  racemosa  (blackish  brown). 
' '       Thespesia  lampas. 
esparto  (reddish  brown) . 

aloe  (mostly  reddish  brown,  sometimes  greenish  and  even  blue). 
New  Zealand  flax  (j^ellow,  green  to  blue,  depending  on  the  purification  of  the 
fiber). 

14.  Lignin.^The  fibers  in  the  second  class  have  their  cellulose  largely 
contaminated  with  lignin,  and  hence  have  somewhat  of  the  character 
of  woody  tissue.  It  is  to  be  remarked,  however,  that  by  treatment  with 
nitric  acid  (or  by  boiling  with  caustic  potash  under  pressure)  these  fibers 
lose  most  of  the  lignin  which  encrusts  their  tissues,  and  then  exhibit 
the  characteristics  of  ordinary  cellulose;  that  is  to  say,  they  dissolve 
hi  Schweitzer's  reagent,  and  are  colored  blue  with  the  iodine-sulfuric  acid 
reagent. 

Ammoniacal  copper  oxide  (Schweitzer's  reagent)  is  a  reagent  which 
gives  characteristic  reactions  with  many  vegetable  fibers,  as  follows: 

(a)  The  Fibers  are  almost  Completely  Dissolved:  ^ 
Cotton. 

Cottonised  ramie. 
^  With  the  exception  of  the  external  cuticle,  the  inner  cell-wall,  and  dry  protoplasmic 
residue.     For  the  morphological  alterations  which  the  fibers  undergo  by  treatment 
with  this  reagent,  see  under  the  description  of  the  separate  fibers. 


350  THE   VEGETABLE   FIBERS 

Raw  fiber  of  Hibiscus  cannahinus. 
"  "      Calotropis  gigantea. 

"    flax. 
' '     hemp  (only  the  bast  cells  dissolve,  the  accompanying  parenchymous  cells 

remain  undissolved). 
' '    sunn  hemp. 

(b)  The  Fiber  becomes  Blue  in  Color  and  is  More  or  Less  Swollen: 
Raw  jute. 

"     fiber  of  Abelmoschus  tetraphyllos. 

"  "       Urena  sinuata. 

"  "      Bauhinia  racemosa. 

"  "      Thespesia  lampas. 

"    New  Zealand  flax. 

"     fiber  of  Aloe  perfoliaia  (shghtly  swollen). 

"  "      5rome/ia  tara/as  (strongly  swollen). 

"  "      Sida  retusa  (becomes  greenish  at  first,  then  blue  and  swells  up) . 

(c)  The  Fiber  is  Colored  WiXHOirr  Swelling: 
Vegetable  sUk  (blue) . 

Bombax  cotton  (blue). 
Raw  esparto  (bright  green) . 

' '     fiber  of  Cordia  latifolia  (blue) . 

"  "      Sterculia  lilbsa  (blue) . 

A  solution  of  aniline  sulfate  may  be  used  to  detect  lignification  in  a 
fiber;  this  reagent  gives  the  following  color  reactions: 

(a)  The  Color  of  the  Fiber  is  not  Changed  or  but  Slightly: 
Cotton. 

Bombax  cotton  (very  slight  coloration). 
Cottonised  ramie,  also  the  bast  cells  of  raw  ramie. 
Raw  flax. 

' '     bast  fibers  of  Hibiscus  cannahinus  (very  slight  coloration) . 

"       "  "       Calotropis  gigantea  (very  slight  coloration) . 

"     sunn  hemp. 

' '     New  Zealand  flax  (very  sUght  coloration) . 
Manila  hemp  (very  slight  coloration) . 
(6)  The  Fiber  is  Distinctly  or  Very  Strongly  Colored: 
Vegetable  siUc  (intense  citron-yellow). 
Raw  jute  (golden  j'ellow  to  orange). 

' '     bast  fibers  of  Abelmoschus  tetraphyllos  (golden  yellow). 

"       "  "       Urena  sinuata  (golden  yellow) . 

"       "  '>'       Sida  retusa  (yellow) . 

"       "    fiber  of  Thespesia  lampas  (golden  yellow) . 

"       "  "      Cordia  latifolia  {dnll  yellow). 

' '     hemp  (pale  yellow) . 

"     esparto  (sulfur  yellow). 

' '     fiber  of  Bromelia  karatas  (golden  yellow) . 

A  method  for  the  estimation  of  the  amount  of  lignin  in  fibers  is  given 
by  Herzog.^  It  is  based  on  a  determination  of  the  methyl  value,  that  for 
pure  lignin  being  taken  as  52.9. 

>  Chem.  Zeit.,  vol.  20,  p.  461. 


CHEMICAL  INVESTIGATION  OF  VEGETABLE   FIBERS 


351 


The  following  table  gives  the  methyl  value  and  corresponding  amount 
of  lignin  in  the  different  fibers: 


Fiber. 


Water, 
Percent. 


Methyl  Value 
on  Fiber 
Dried  at 
100°  C. 


Lignin, 
Percent. 


Bombax  cotton 

Vegetable  silk  {Calotropis  gigantea) 

Manila  hemp 

Pita 

Aloe 

Coir 

TUlandsia 

Nettle 

Ramie 

Fiber  of  Moras  papyrifera 

Linen,  Russian 

' '       Courtrai 

Hemp,  Italian 

PoUsh 

Jute 


6.77 
6.88 
6.81 
7.10 
7.90 
7.36 
8.10 
8.15 
7.84 
6.08 
8.40 
8.71 
7.93 
8.20 
8.06 


6.87 

8.18 

15.92 

8.47 

9.11 

22.00 

11.18 

0.77 


50 
81 

80 

87 


21.20 


12.99 
15.46 
30.11 
16.02 
17.32 
41.59 
21.13 

1.46 

4.74 
0.92 

5.33 

5.46 

40.26 


When  a  substance  containing  a  methoxyl  group  is  heated  with  hydri- 
odic  acid,  methyl  iodide  is  formed,  and  the  so-called  "  methyl  value  " 
refers  to  the  amount  of  methyl  iodide  thus  formed.  The  determinatit  n 
is  carried  out  as  follows:  The  fibrous  material  is  finely  divided  and  fron. 
0.2  to  0.3  gram  is  heated  with  10  cc.  of  hydriodic  acid  (sp.  gr.  1.70)  in  r 
flask  on  a  glycerol  bath,  while  a  current  of  carbon  dioxide  gas  is  passed 
through  the  flask.  The  vapors  produced  are  passed  through  a  three- 
bulb  condenser,  the  first  bulb  being  empty  to  condense  the  steam,  the 
second  containing  water  to  absorb  the  hydriodic  acid,  and  the  third  con- 
taining red  phosphorus  to  retain  any  iodine  liberated  by  the  decompo- 
sition of  the  hydriodic  acid.  The  vapors  of  methyl  iodide  (mixed  with 
carbon  dioxide)  issuing  from  the  bulbs  are  passed  into  a  flask  containing 
a  mixture  of  5  cc.  of  a  40  percent  solution  of  silver  nitrate  with  50  cc. 
of  95  percent  alcohol.  The  methyl  iodide  is  precipitated  as  silver  iodide, 
which  is  weighed  in  the  usual  manner;  100  parts  of  silver  iodide  are  equiva- 
lent to  6.4  parts  of  methyl. 

15.  Chemical  Investigation  of  Vegetable  Fibers. — A  chemical  study 
of  the  fibers  involves  an  examination  of  their  chemical  constituents.  As 
previously  stated,  though  cellulose  is  the  p)rincipal  chemical  compound 
to  be  found  in  vegetable  fibers,  yet  there  are  certain  other  substances 
present,  which  at  times  may  be  characteristic  of  the  fiber.     Then,  again, 


352  THE   VEGETABLE   FIBERS 

the  cellulose  which  occurs  in  different  classes  of  fibers  appears  to  be  some- 
what different  in  its  chemical  properties,  which  has  led  to  the  supposition 
of  different  forms  of  cellulose,  already  spoken  of  as  ligno-cellulose,  pecto- 
cellulose,  etc.  Though  the  chemistry  of  these  bodies  has  been  somewhat 
studied  with  reference  to  vegetable  fibers  by  Cross  and  Bevan  and  a  few 
others,  yet  the  subject  is  still  in  a  very  crude  condition,  and  there  is  much 
to  be  learned  in  this  field  of  chemical  research.  The  methods  for  the 
chemical  study  of  the  vegetable  fibers  adopted  by  Cross,  and  continued 
by  other  chemists,  may  be  stated  in  the  following  form: 

A  separate  portion  of  the  fiber  under  examination  is  taken  for  each  determination, 
and  the  results  are  calculated  into  percentages  on  the  dry  weight  of  the  substance. 

(1)  Moisture. — This  may  be  called  hygroscopic  water  or  water  of  condition;  it  is 
obtained  by  drying  a  weighed  portion  of  the  fiber  at  110°  C.  to  constant  weight.' 
If  dried  at  100°  C,  about  1  percent  of  the  water  will  be  retained.  The  percentage  of 
hygroscopic  moisture  in  the  vegetable  fibers  varies  considerably  with  the  different  state 
of  humidity  of  the  surrounding  air,  on  which  account  it  is  recommended  that  the 
results  of  the  analyses  should  be  expressed  on  the  dry  weight  of  the  fiber.  It  is  inter- 
esting to  note  that  the  contents  of  hygroscopic  moisture  in  a  fiber  appears  to  be  an 
index  of  susceptibiUty  of  attack  by  hydrolytic  agents,  and  that  the  highest  class  of 
fibers  is  distinguished  by  its  relatively  low  amount  of  moisture. 

(2)  Ash. — This  is  taken  as  the  total  residue  left  after  ignition  of  the  fiber,  and 
represents  the  mineral  constituents.  The  proportion  of  these  is  low  in  the  hgno- 
celluloses  and  higher  in  the  pecto-celluloses,  especially  when  the  proportion  of  non- 
cellulose  is  high.  Admixture  of  non-fibrous  tissue  will  also  raise  the  amount  of  ash, 
as  this  tissue  contains  a  higher  proportion  of  mineral  constituents.  The  natural  ash 
of  vegetable  fibers  varies  from  0.5  to  2  percent,  and  usually  the  major  portion  of  this 
consists  of  silica.  The  exact  function  of  this  sihcious  matter  in  the  plant  cell  is  not 
known;  according  to  Ladenburg  (Berichte,  1872,  p.  568)  and  Lange  {Berichte,  1884, 
p.  822)  the  silica  does  not  have  any  structural  function  in  the  cell. 

(3)  Hydrolysis. — This  refers  to  the  loss  of  weight  sustained  by  the  fiber  (o)  on 
boiling  for  five  minutes  with  a  1  percent  solution  of  caustic  soda,  and  (6)  further  loss 
of  weight  on  continuing  to  boil  for  one  hour.  The  first  loss  in  weight  represents  the 
proportion  of  fiber  soluble  in  the  alkali,  the  second  represents  the  proportion  of  the 
fiber  decomposed  by  actual  hydrolysis.  The  pecto-celluloses  are  often  so  resolved  by 
the  action  of  the  dilute  alkali  that  most  of  the  non-cellulose  is  dissolved  away.  The 
amount  of  hydrolysis  of  a  fiber  represents  in  some  measure  the  power  of  resistance  of 
a  fiber  to  the  action  of  the  boiling-out  aiid  bleaching  processes,  as  well  as  the  power 
of  resistance  to  actual  wear  as  caused  by  frequent  washings  with  alkalies,  soaps,  etc. 

(4)  Cellulose. — The  determination  of  the  value  and  composition  of  the  cellulose  is 
made  as  follows:  A  sample  of  the  fiber  is  first  boiled  for  five  minutes  in  a  1  percent 
solution  of  caustic  soda,  well  washed,  and  then  exposed  for  one  hour  at  the  ordinary 
temperature  to  an  atmosphere  of  chlorine  gas;  after  which  it  is  removed,  washed, 
and  treated  with  an  alkaline  solution  of  sodium  sulfite,  gradually  raising  to  the  boil. 
After  several  minutes  the  fiber  is  washed,  and  finally  treated  with  dilute  acetic  acid, 

'  According  to  Ostwald,  water  is  held  in  combination  with  cellulose  fibers  in  five 
different  forms:  (1)  as  water  of  the  cellulose,  (2)  as  capillary  water,  (3)  as  colloidal 
water,  (4)  as  osmotically  combined  water,  (5)  as  chemically  combined  water,  or  water 
of  hydration. 


CHEMICAL  INVESTIGATION  OF   VEGETABLE   FIBERS 


353 


washed,  dried,  and  weighed.     The    residue  is    taken    as  cellulose,  and    affords  an 
important  criterion  as  to  the  composition  and  value  of  the  raw  fiber. 

(5)  Mercerising. — This  is  represented  by  the  loss  in  weight  sustained  by  the  fiber 
after  treatment  for  one  hour  cold  with  a  33  percent  solution  of  caustic  potash.  The 
action  of  the  alkaU  often  causes  a  considerable  change  in  the  structure  of  the  fiber, 
especially  with  those  fibers  made  up  of  a  number  of  fibrils  aggregated  into  bundles. 

(6)  Nitration. — This  is  represented  by  the  increase  in  weight  sustained  by  the 
fiber  when  treated  for  one  hour  with  a  mixture  of  equal  volumes  of  nitric  and  sulfuric 
acids.     Any  change  in  color  is  also  noted. 

(7)  Add  Purification. — This  is  represented  by  the  loss  in  weight  sustained  by  the 
fiber  after  boihng  with  20  percent  acetic  acid,  washing  with  alcohol  and  water,  and 
drying.  This  treatment  is  intended  to  remove  from  the  fiber  all  accidental  impurities 
with  a  minimum  alteration  in  composition. 

(8)  Carbon  Percentage. — The  fiber  treated  as  above  (7)  is  subjected  to  a  com- 
bustion in  the  presence  of  chromic  anhydride  and  sulfuric  acid,  and  the  resulting  gas, 
composed  of  a  mixture  of  carbon  monoxide  and  dioxide,  is  collected  and  measured. 
As  the  two  oxides  of  carbon  have  the  same  molecular  volume,  the  amount  of  carbon 
in  unit  volume  is  independent  of  the  composition  of  the  gas.  The  amount  of  carbon 
in  cotton  cellulose  (the  tj^jical  cellulose)  is  44.4  percent;  the  compound  celluloses, 
however,  have  either  a  lower  percentage  in  the  one  class  (40  to  43  percent),  or  a 
higher  percentage  in  the  second  class  (45  to  50  percent),  the  pecto-celluloses  being 
included  in  the  first  class  and  the  hgno-celluloses  in  the  second  class. 


The  following  table  shows  the  results  obtained  with  the  principal  fibers 
when  analysed  by  the  above  method: 


Mois- 
ture, 
Per- 
cent. 

Ash, 
Per- 
cent. 

Hydrolysis. 

Cellu- 
lose, 
Percent. 

Mercer- 
ising, 
Percent. 

Nitra- 
tion, 
Percent. 

Acid 
Purifi- 
cation, 
Percent. 

Car- 

a. 
Per- 
cent. 

b, 
Per- 
cent. 

bon, 
Per- 
cent. 

r  Flax 

9.3 
9.0 
7.3 
4.5 

8.5 

10.3 
10.7 
10.7 
10.6 
10.7 

10.5 

9.7 

13.4 

12.2 

1.6 
2.9 
2.5 
1.5 
1.4 

1.1 

0.6 
1.8 
2.2 
1.5 

1.4 

14.6 

13.0 

13.0 

6.2 

8.3 

13.3 

6.6 

11.9 

14.0 

9.8 

10.0 
12.0 
11.0 

22.2 
24.0 
17.6 
10.1 
11.7 

18.6 
12.2 
18.5 
19.5 
14.2 

20.0 
16.5 
33.0 

11.8 

81.9 
80.3 
76.5 
88.3 
83.0 

76.0 
83.1 
77.7 
73.0 
74.0 

75.8 
73.1 
64.6 
70.0 

8.4 
11.0 

4.6 
11.3 

11.0 

6.6 

13.6 

16.0 

9.6 

11.0 

11.0 

123.0 
125.0 
153.0 
131.0 
150.5 

128.0 
137.2 

109.8 

106.0 

91.3 

104.0 

4.5 
6.5 

8.5 
0.8 

2.7 

2.5 
0.4 
4.0 

3.4 

1.1 

2.5 
4.0 

43  0 

H 

Ramie 

Calotropis .... 
Marsdenia. . . . 
S.  hemp 

f  Jute 

44.6 
44.3 
47.0 

45  2 

B  . 
C 

Sida  retusa.. . . 

Urena 

Hibiscus  can.  . 
^  Hibiscus  sp.  .  . 

Agave  amer.  .  . 
Sansevieria  sp . 

Musa 

Fourcroya .... 

45.2 

44.9 
44.5 

CHAPTER  XIII 
COTTON 

1.  Historical. — The  use  of  cotton  as  a  textile  fiber  dates  back  to  antiq- 
uity, mention  of  it  being  found  in  the  writings  of  Herodotus  (445  B.C.) : 
"  There  are  trees  which  grow  wild  there  (India),  the  fruit  of  which  is  a  wool 
exceeding  in  beauty  and  goodness  that  of  sheep.  The  Indians  make  their 
clothes  of  this  tree-wool."  The  same  writer  also  refers  to  the  clothing 
of  Xerxes'  army  as  being  composed  of  "  cotton  fiber."  Theophrastus 
(350  B.C.)  gives  a  definite  statement  as  to  manner  in  which  the  cotton 
plant  was  cultivated  in  India.  Cotton  was  used  in  India,  Egypt,  and 
China.  The  first  European  country  to  manufacture  cotton  goods  appears 
to  have  been  Spain. 

A  rather  ambiguous  passage  in  the  Historia  Critica  de  Espana  indicates 
that  the  manufacture  of  linen,  silk,  and  cotton  existed  in  Spain  as  early 
as  the  ninth  century.  De  Maries  states  that  cotton  manufacture  was 
introduced  into  Spain  during  the  reign  of  Abderahman  III.,  in  the  tenth 
century,  by  the  Moors.  In  the  fourteenth  century  Granada  was  noted 
for  its  manufacture  of  cotton.  A  commercial  historiographer  of  Barcelona 
states  that  one  of  the  most  famous  and  useful  industries  of  that  city  was 
the  manufacture  of  cotton;  its  workers  were  united  in  a  guild  in  the 
thirteenth  century,  and  the  names  of  two  of  its  streets  have  preserved 
the  memory  of  the  ancient  locality  of  their  shops.  There  is  much 
uncertainty  as  to  when  the  manufacture  of  cotton  was  first  introduced 
into  England;  the  first  authentic  record  of  such  is  in  Robert's  Treasure 
of  Traffic,  published  in  1641. 

The  use  of  cotton  in  India  dates  back  to  prehistoric  times,  and  it  is 
often  referred  to  as  early  as  800  B.C.  in  the  ancient  laws  of  Manu.  It 
may  be  stated  that  from  1500  B.C.  to  about  the  beginning  of  the  six- 
teenth century,  India  was  the  center  of  the  cotton  industry,  and  the  cloth 
which  was  woven  in  a  rather  crude  and  primitive  manner  has  rarely  been 
equaled  for  fineness  and  quality. 

The  earliest  mention  of  cotton  appears  to  be  in  the  Asvaldyana  Sranta 
Seitra  (about  800  B.C.).  The  following  quotations  are  from  the  Books  of 
Manu.  The  sacrificial  thread  of  the  Brahmin  must  be  made  of  cotton 
(karpasi),  so  as  to  be  put  over  the  head  in  three  strings.  Let  a  weaver 
who  has  received  10  palas  of  cotton  thread  give  it  back  increased  to  11 

354 


HISTORICAL 


355 


by  the  rice-water  and  the  Hke  used  in  weaving;  he  who  does  otherwise 
shall  pay  a  fine  of  12  panas.  Theft  of  cotton  thread  was  made  punishable 
by  fines  of  three  times  the  value  of  the  article  stolen.  In  the  Hebrew 
Scriptures  cotton  is  mentioned  under  the  name  Kirhas  (or  Karpas),  as 
when  describing  the  green  draperies  at  the  palace  of  Susa  {Esther  I,  6.) 
Among  the  Latin  authors  of  the  Augustan  age  curtains  and  tents  of  carbasa 
are  frequently  mentioned. 

Two  Arabian  travelers  of  the  Middle  Ages,  writing  of  India,  say: 
"  In  this  country  they  make  garments  of  such  extraordinary  perfection 
that  nowhere  else  are  the  like  to  be  seen;  these  garments  are  woven  to 
that  degree  of  fineness  that  they  may  be  drawn  through  a  ring  of  moderate 
size."     Marco  Polo,  about  A.D.  1298,  mentions  India  as  producing  "  the 


Fig.  154. — Microphotograph  of  Ordinary  American  Cotton. 

finest  and  most  beautiful  cottons  that  are  to  be  found  in  any  part  of  the 
world."  Tavernier,  in  his  Travels,  says  of  India  that  some  calicoes  are 
made  so  fine  that  one  can  hardly  feel  them  in  the  hand,  and  the  thread 
when  spun  is  scarcely  discernible;  that  the  rich  have  turbans  of  so  fine  a 
cloth  that  30  ells  of  it  weigh  less  than  4  ozs.  The  poetic  writers  of  the 
Orient  call  these  cloths  "  webs  of  woven  wind."  There  is  the  record  of 
a  muslin  turban  thirty  yards  in  length,  contained  in  a  cocoanut  set  with 
jewels,  which  was  so  exquisitely  fine  that  it  could  scarcely  be  felt  by  the 
touch.^ 


1  The  superior  fineness  of  some  Indian  muslins,  and  their  quality  of  retaining, 
longer  than  European  fabrics,  an  appearance  of  excellence,  has  occasioned  the  beUef 
that  the  cotton  fiber  from  which  they  are  woven  is  superior  to  any  known  elsewhere; 
this,  however,  is  so  far  from  being  the  fact,  that  no  cotton  is  to  be  found  in  India  that 
at  all  equals  in  quality  the  better  kinds  grown  in  the  United  States.  The  excellence 
of  these  Indian  muslins  must  be  wholly  ascribed  to  the  skillfulness  and  patience  of 


356  COTTON 

Cotton  was  introduced  into  China  and  Japan  from  India,  but  its 
adoption  by  these  countries  was  slow.  Fesca  (Japanische  Landwirih- 
schaft,  Pt.  II,  p.  485)  says  that  cotton  was  introduced  into  Japan  acci- 
dentally in  the  year  A.D.  781  from  India,  but  its  cultivation  was  not 
continued.  Several  centuries  later  it  was  no  doubt  introduced  again 
by  the  Portuguese;  it  was  not,  however,  until  the  seventeenth  century, 
during  the  reign  of  Tokugawa,  that  the  cultivation  of  cotton  became  at 
all  general  in  Japan.  A  great  deal  of  cotton  is  now  grown  in  Korea, 
having  been  introduced  into  that  country  from  China  about  500  years 
ago.  The  Korean  cotton  is  of  longer  staple  and  of  better  quality  than 
the  Chinese  cotton,  as  the  soil  and  climate  in  Korea  are  better  adapted 
to  its  growth.  In  the  seventh  century  the  cotton  plant  was  used  as  an 
ornamental  shrub  in  Chinese  gardens;  and  it  was  not  until  about  A.D.  1000 
that  the  plant  was  commercially^  grown  in  China. 

Cotton  was  probably  introduced  into  China  at  the  time  of  the  conquest 
of  this  country  by  the  Tartars,  but  it  was  not  imtil  about  A.D.  1300 
that  the  fiber  was  cultivated  for  manufacturing  purposes.  Marco  Polo 
(Book  II,  Ch.  24)  gives  no  account  of  the  culture  of  cotton  in  China, 
except  in  the  province  of  Fo-Kien,  but  speaks  of  silk  as  being  the  cus- 
tomary dress  of  the  people. 

In  Egypt  there  is  some  question  as  to  whether  or  not  cotton  was  used 
except  in  rather  late  times,  flax  being  the  common  article  in  that  country 
for  the  manufacture  of  cloth.  But  there  is  evidently  a  good  deal  of  con- 
fusion in  the  early  writers  respecting  the  terms  used  for  "  flax  "  and 
"  cotton,"  and  it  may  be  that  the  ancient  Egyptians  were  better  acquainted 
with  the  use  of  the  cotton  fiber  than  we  imagine;  we  at  least  know  that 
the  cotton  plant  was  grown  there  at  a  very  early  date.  Herodotus  states 
that  the  Egyptian  priests  wore  linen  clothes,  but  Pliny  refers  to  them  as 
also  wearing  cotton  material,  and  Philostratus  supports  this  latter  state- 
ment. The  words  translated  as  "  linen  "  do  not  always  refer  to  the  fiber 
of  which  the  cloth  was  made,  but  often  have  reference  to  the  general 
appearance  of  the  material;  therefore,  cloth  made  from  either  flax  or  cotton 
alone,  or  mixed,  was  called  linen.  Even  the  fact  that  all  Egyptian  mummy- 
cloths  so  far  examined  appear  to  consist  of  flax  is  no  argument  against 
the  probable  use  of  cotton  by  these  people;  it  only  proves  that  flax  alone 

the  workmen,  as  shown  in  the  different  processes  of  spinning  and  weaving.  Their 
yarn  was  spun  upon  a  distaff  and  it  is  owing  to  the  dexterous  use  of  the  finger  and 
thumb  in  forming  the  thread,  and  to  the  moisture  which  it  imbibes,  that  these  fibers 
are  more  perfectly  incorporated  than  they  can  be  through  the  employment  of  any 
mechanical  substitutes.  The  very  fine  mushns  which  thus  attest  the  efficiency  of 
some  of  the  East  Indians,  and  which  have  been  poetically  described  as  "webs  of 
woven  wind,"  are,  however,  viewed  as  curiosities  even  in  the  country  of  their  pro- 
duction, and  are  made  only  in  very  small  quantities, 


HISTORICAL 


357 


was  employed  for  certain  religious  purposes,  and  cotton,  wool,  and  silk, 
may  have  been  in  common  use  for  the  clothing  of  the  people. 

The  use  of  cotton  was  evidently  known  to  the  Greeks  soon  after  the 
invasion  of  India  by  Alexander,  though  this  does  not  signify  that  the 
Greeks  themselves  either  grew  the  cotton  plant  or  engaged  in  the  manu- 
facture of  the  fiber  into  clothes.  Aristobulus,  a  contemporary  of  Alex- 
ander, mentions  the  cotton  plant  under  the  name  of  the  ''  wool-bearing 
tree,"  and  states  that  the  capsules  of  this  tree  contain  seeds  which  are 


Fig.  155. — American  Upland  Cotton  Shrub.     (After  Dodge.) 


taken  out,  and  the  remaining  fiber  is  then  combed  like  wool.  Nearchus, 
an  admiral  of  Alexander,  about  327  B.C.,  says:  "  There  are  in  India  trees 
bearing,  as  it  were,  bunches  of  wool.  The  natives  made  linen  garments 
of  it,  wearing  a  shirt  which  reached  to  the  middle  of  the  leg,  a  sheet  folded 
about  the  shoulders,  and  a  turban  rolled  around  the  head.  The  linen 
made  by  them  from  this  substance  was  finer  and  whiter  than  any  other." 
The  cotton  plant  does  not  appear  to  have  been  cultivated  in  Italy 
until  some  time  after  the  beginning  of  the  Christian  era,  although  a 
knowledge  of  the  fiber  and  a  probable  use  of  the  cloth  made  from  it  was 


358 


COTTON 


no  doubt  known  to  them  a  long  time  previous.  Miiller  ^  states  that 
cotton  cloth  was  used  for  clothing  by  the  Romans  prior  to  A.D.  284 
For  the  real  introduction  into  Europe  of  the  cotton  plant  and  the  manu- 
facture of  the  fiber  into  cloth  we  must  look  to  the  Mohammedans,  who 
spread  this  knowledge  throughout  the  countries  bordering  on  the  Medi- 


Fig.  156. — Sea-island  Cotton  Shrub.     (After  Dodge.) 


terranean  Sea  during  the  period  of  their  wide-spread  conquests.  Abu 
Zacaria  Ebn  el  Awam,  a  Moorish  writer  of  the  twelfth  century,  gives  a 
full  account  of  the  proper  method  of  cultivating  the  cotton  plant,  and 
also  mentions  that  cotton  was  cultivated  in  Sicily. 

The  various  names  given  to  the  cotton  fiber  in  different  countries  may 
be  of  interest;  they  are  as  follows: 

^  Handbuch  der  Mas.  Alterth.  Wissensch.,  vol.  4,  p.  873. 


HISTORICAL 


359 


India Pucii 

Spain Algodon 

Yucatan  and  ancient  Me.xico Ychcaxihitvitl 

Tahiti Vavai 

France Coton 

Italy Cotone 

Germany Baumwolle 

Persia Pembeh  or  Poombeh 

Arabia Gatn,  Kotan,  or  Kutn 

Cochin  China Cay  Haung 

China Hoa  mein 

Japan Watta  ik  or  Watta  noki 

Siam Tonfaa 

Hindoostan Nurma 

Mysore  and  Bombay Deo  Kurpas  and  Deo  Kapas 

Mongolia Kohung 

The  English  word  "  cotton  "  is,  in  fact,  derived  from  the  Arabic  Katdn 
(or  qutn,  kuteen),  though  it  is  claimed  this  name  originally  denoted  flax. 
The  word  li7ion  was 
itself  at  one  time  used 
to  denote  cotton,  and 
even  at  the  present 
time  we  speak  of  the 
cotton  fibers  as  lint. 
In  early  times  it  was 
used  rather  to  denote 
a  particular  texture 
than  to  describe  a 
distinct  fiber.  For  in- 
stance, we  find  "  Man- 
chester Cottons  " 
(1590)  as  a  name  for 
a  certain  woolen  fab- 
ric. England  first 
came  into  prominence 
as  a  cotton  manufac- 
turing country  in  1635, 
the  supply  of  the  raw 
fiber  being  obtained 
from  the  East.  Long 
previous  to  this, 
however,  England   as 

well  as  other  European  countries,  had  imported  cotton  goods  (calicoes, 
etc.)  from  India  by  way  of  Venice.  The  introduction  of  the  cheaper 
cotton  fabrics  was  vigorously  opposed  in  England  as  being  destructive 


Fig.  157.— Leaf  of  the  Cotton  Plant. 


360 


COTTON 


of  the  woolen  industry.  By  an  Act  of  1720  the  use  and  wear  in  England 
of  printed,  painted,  or  dyed  caHcoes  was  prohibited.  As  to  the  knowledge 
and  use  of  cotton  in  the  Western  Hemisphere,  this  also  seems  to  have 
extended  to  very  early  times,  for  when  Columbus  first  came  to  the  West 
Indies  in  1492,  he  found  cotton  extensively  cultivated,  and  the  inhabi- 
tants of  these  islands  wove  cloth  from  the  fiber.  Among  the  Mexicans 
cotton  was  found  to  be  the  chief  article  of  clothing,  as  these  people  did 
not  possess  either  wool  or  silk  and  were  not  acquainted  with  the  use  of 

flax,  although  the  plant  grew 
in  their  country.  Among  the 
presents  sent  by  Cortez  to 
Charles  V.  of  Spain  were 
many  fabrics  made  from 
cotton.  In  Peru  cotton  was 
also  in  use  from  an  early 
date,  and  at  the  time  of 
Pizarro's  conquest  of  that 
country  in  1522  the  inhabi- 
tants were  clothed  in  cotton 
garments;  cotton  cloths  have 
also  been  found  on  Peruvian 
mummies  of  a  very  ancient 
date.  Furthermore,  the  cot- 
ton plant  is  indigenous  to 
Peru  and  from  it  is  obtained 
a  special  variety  known  as 
Peruvian  cotton.  According 
to  Bancroft,  the  first  attempt 
towards  cotton  cultivation  in 
the  American  colonies  was  in 
Virginia,  during  Wyatt's 
administration,  in  1621.  In 
1733  the  cultivation  of  cotton 
was  started  in  Carolina,  and 
the  following  year  in  Georgia.  In  1748  the  first  consignment  of 
Georgian  cotton  was  sent  to  England.  In  1758  white  Siam  cotton 
was  introduced  into  Louisiana.  In  1784  fourteen  bales  of  cotton  arrived 
in  Liverpool  from  America,  of  which  eight  bales  were  seized  on  the 
ground  that  so  much  cotton  could  not  have  been  produced  in  the 
United  States.  In  1786  the  black-seeded  cotton  from  the  Bahamas 
was  introduced  into  Georgia. 

The  first  mill  in  the  United  States  for  the  manufacture  of  cotton 
goods  appears  to  have  been  erected  at  Beverly,  Massachusetts,  in  1787. 


Fig.  158. — Leaf  and  Flower  of  Sea-island  Cotton 
(After  Bulletin  No.  33,  U.  S.  Dept.  Agric.) 


ORIGIN  AND  GROWTH  361 

2.  Origin  and  Growth. — The  cotton  fiber  consists  of  the  seed-hairs 
of  several  species  of  the  genus  Gossypium,  belonging  to  the  natural  order 
of  Malvacece}  The  cotton  plant  is  a  shrub  which  reaches  the  height 
of  four  to  six  feet.  It  is  probably  indigenous  to  nearly  all  subtropical 
countries,  though  it  appears  to  be  best  capable  of  cultivation  in  warm, 
humid  climates  where  the  soil  is  sandy,  and  in  the  neighborhood  of  the 

1  The  following  is  a  description  of  the  botany  of  cotton  given  in  Bulletin  No.  33 
of  the  U.  S.  Department  of  Agriculture:  The  cotton  plant  belongs  to  the  Malvaceae, 
or  the  mallow  family,  and  is  known  scientifically  by  the  generic  name  Gossypium. 
It  is  indigenous  principally  to  the  islands  and  maritime  regions  of  the  tropics,  but 
under  cultivation  its  range  has  been  extended  to  40°  or  more  on  either  side  of  the 
equator,  or  to  the  isothermal  line  of  60°  F.  In  the  United  States  latitude  37°  north 
about  represents  the  limit  of  economic  growth.  The  Gossypium  plant  is  herbaceous, 
shrubby,  or  arborescent,  perennial,  but  in  cultivation  herbaceous  and  annual  or 
biennial,  often  hairy,  with  long,  simple,  or  slightly  branched  hairs,  or  soft  and  tomen- 
tose,  or  hirsute,  or  all  the  pubescence  short  and  stellate,  rarely  smooth  throughout; 
stem,  branches,  petioles,  peduncles,  leaves,  involucre,  corolla,  ovary,  style,  capsule, 
and  sometimes  the  cotyledons  more  or  less  covered  with  small  black  spots  or  glands. 
Roots  tap-rooted,  branching,  long,  and  penetrating  the  soil  deeply.  Stems  erect, 
terete,  with  dark-colored  ash-red,  or  red  bark  and  white  wood,  branching  or  spreading 
widely.  Branches  terete  or  somewhat  angled,  erect  or  spreading,  or  in  cultivation 
sometimes  very  short.  Leaves  alternate,  petioled,  cordate,  or  subcordate,  3-  to  7-, 
or  rarely  9-lobed,  occasionally  some  of  the  lower  and  upper  ones  entire,  3-  to  7- veined. 
Veins  branching  and  netted;  the  midvein  and  sometimes  adjacent  ones  bear  a  gland 
one-third  or  less  the  distance  from  their  bases,  or  glands  may  be  whoUy  absent. 
Stipules  in  pairs,  Unear-lanceolate,  acuminate,  often  ceduous.  Flowers  pedunculate. 
Peduncles  subangular  or  angular,  often  thickened  towards  the  ends,  short  or  very 
short,  erect  or  spreading;  the  fruit  is  sometimes  pendulous,  sometimes  glandular, 
bearing  a  leafy  involucre.  Involucre  3-leaved,  or  in  cultivation  sometimes  4;  bracteoles 
often  large,  cordate,  erect,  appressed  or  spreading  at  summit,  sometimes  coalescent  at 
base  or  adnate  to  the  calyx,  dentate  or  laciniate,  sometimes  entire  or  nearly  so,  rarely 
linear.  Caly:x  short,  cup-shaped,  truncate,  shortly  5  dentate  or  more  or  less  5-parted. 
Corolla  hypogynous.  Petals  5,  often  coalescent  at  base  and  by  their  claws  adnate  to 
the  lower  part  of  stamen  tube,  obovate,  more  or  less  unequally  transversely  dilated  at 
summit,  convolute  in  bud.  Staminal  column  dilated  at  base,  arched,  surrounding  the 
ovary,  naked  below,  above  narrowed  and  bearing  the  anthers.  Filaments  numerous, 
filiform,  simple  or  branched,  conspicuous,  exserted.  Anthers  kidney-shaped,  1-ceUed, 
dehiscent  by  a  semicircular  opening  into  two  halves.  Ovary  sessile,  simple,  3-  to 
5-celled.  Ovules  few  or  many,  in  two  series.  Style  clavate,  3-  to  5-parted;  divisions 
sometimes  erect,  sometimes  twisted  and  adhering  together,  channeled,  bearing  the 
stigmas.  Capsule  more  or  less  thickened,  leathery,  oval,  ovate-acuminate,  sub- 
globose,  mucronate,  loculicidally  dehiscent  by  3  to  5  valves.  Seed  numerous,  sub- 
globose,  ovate  or  subovate,  oblong  or  angular,  densely  covered  with  cotton  or  rarely 
glabrous.  Fiber  sometimes  of  two  kinds,  one  short  and  closely  adherent  to  the  seed, 
the  other  longer,  more  or  less  silky,  of  single  simple  flattened  cells  more  or  less  spirally 
twisted,  more  readily  separable  from  the  seed.  Albumin  thin,  membranous,  or  none. 
Cotyledons  plicate,  arriculate  at  base  enveloping  the  straight  radicle. 

The  Malvacew.  is  represented  by  about  one  thousand  different  species,  a  great  many 
of  which  are  of  some  economic  value  to  man. 


362 


COTTON 


sea,  lakes,  or  large  rivers.  It  appears  to  thrive  most  readily  in  North  and 
South  America,  India,  and  Egypt;  it  has  also  been  cultivated  in  Australia, 
but  not  as  yet  with  any  great  degree  of  success;  inferior  qualities  have 
been  grown  along  the  coasts  of  Africa;  that  grown  in  Europe  (Italy  and 
Spain)  is  practically  negligible  as  far  as  commercial  considerations  are 
concerned.  In  addition  to  the  numerous  varieties  of  cultivated  cottons, 
there  are  various  wild  cotton  plants  to  be  met  with  in  many  parts  of  the 
world.     With  respect  to  the  detailed  botany  of  these  wild  plants,  the 

reader  is  referred  to  the  very 
able  treatise  by  Sir  George 
Watt  on  The  Wild  and 
Cultivated  Cotton  Plants  of 
the  World.  As  to  the  gen- 
eral characteristics  of  these 
wild  cottons,  it  may  be  said 
that  they  all  have  a  red- 
colored  woolly  coating  on 
the  testa  of  the  seed.  In 
some  this  assumes  the  con- 
dition of  a  short  dense  vel- 
vet, called  the  fuzz.  In 
others,  there  are  two  coats 
of  fiber,  an  under-fleece  (the 
fuzz)  and  an  outer  coat  or 
floss.  In  the  third  class 
there  is  no  fuzz,  but  a  dis- 
tinct floss. 

Monie  gives  the  follow- 
ing account  of  the  cultiva- 
tion of  the  cotton  plant: 
"  The  plant,  although  indi- 
genous to  almost  aU  warm 
climates,  is  nevertheless 
only  cultivated  within  a  very  limited  area  for  commercial  purposes, 
the  principal  centers  of  cotton  agriculture  being  in  Egypt,  the  south- 
ern portions  of  the  United  States,  India,  Brazil,  the  west  and  southern 
coasts  of  Africa,  and  the  West  India  Islands.  A  large  amount  of  white 
cotton  is  raised  in  China,  but  this  is  almost  entirely  used  in  the  home 
manufactures.  The  time  when  sowing  is  begun  in  the  different  districts 
varies  considerably,  being  largely  dependent  on  climatic  influences. 
The  seasons,  however,  are  generally  as  follows:  American. — From  the 
middle  of  March  to  the  middle  of  April.  Egyptian. — From  the  beginning 
of  March  to  the  end  of  April.     Peruvian  and  Brazilian. — From  the  end  of 


Fig.  159. — Leaf  and  Flower  of  India  Cotton,  Gossy- 
pium  herhaceum.  (After  Bulletin  No.  33,  U.  S. 
Dept.  Agric.) 


ORIGIN  AND  GROWTH 


363 


December  to  the  end  of  April.  Indian  or  Surat. — From  May  to  the 
beginning  of  August.  In  the  various  American  plantations  the  sowing 
time  begins  and  ends  almost  simultaneously,  while  in  other  countries, 
especially  where  the  atmosphere  and  climate  are  subject  to  much  varia- 
tion, the  period  of  planting  fluctuates;  the  plants  in  some  parts  being 
several  inches  above  the  ground,  while  in  other  parts  of  the  same  country 
the  fields  may  be  only  under  preparation.  When  the  sowing  is  finished, 
and  before,  and  some  time  after  the  crop  makes  its  appearance,  keeping 
the  ground  free  from  weeds  is  the  main  object  to  be  looked  to,  otherwise 
the  soil  would  become  much  impoverished  and  the  product  would  be  of 
an  inferior  quality.  In  from  eight  days  to  a  fortnight  after  sowing,  the 
young  shoots  first  appear  above  ground  in  the  form  of  a  hook,  but  in  a 
few  hours  afterwards  the  seed  end  of  the  stalk  or  stem  is  raised  out  of  the 


a  b  c 

Fig.  160.— The  Cotton  Plant  in  the  Early  Stages  of  Its  Growth. 


ground,  disclosing  two  leaves  folded  over  and  closed  together.  The  leaves 
and  stems  of  these  young  plants  are  very  smooth  and  oily  and  of  a  fleshy 
color  and  appearance,  and,  as  before  stated,  extremely  tender  (Fig.  160,  a). 
In  a  short  time  after  the  plant  has  reached  the  stage  shown  in  the  illustra- 
tion, it  begins  to  straighten  itself  and  deepen  in  color,  or,  rather,  changes 
to  a  light  olive  green,  while  the  two  leaves  gradually  separate  themselves 
until  they  attain  the  forms  shown  in  Fig.  160,  b  and  c.  When  this  stage 
has  been  reached  its  development  is  rapid,  and  proceeds  in  a  similar 
form  to  ordinary  shrubs  until  it  reaches  maturity. 

"In  examining  the  cotton  plant  from  time  to  time  during  its  growth 
some  interesting  and  instructive  objects  will  be  observed.  Firstly,  in 
regard  to  the  formation  of  the  leaves,  it  will  be  found  that  they  vary  in 
shape  on  different  parts  of  the  stem.  Thus,  for  instance,  on  a  Gallini 
Egyptian  (G.  barbadense)  plant  the  lower  leaves  were  entire,  the  center 
or  middle  three-lobed,  while  the  upper  leaves  were  five-lobed.     In  the 


364 


COTTON 


G.  hirsidiim  species  the  lower  leaves  have  five,  and  some  three  lobc-s, 
with  the  small  branch  petioles  of  a  hairy  nature,  while  the  upper  leaves 
are  entire  and  undivided.  In  the  Peruvian  cotton  plant  the  lower  leaves 
are  entire  and  of  an  oval  shape,  while  the  upper  leaves  have  five  acuminated 
lobes. 

"Another  interesting  point  observable  in  the  growth  of  the  cotton  plant 
is  the  presence  of  a  small  cavity  situated  at  the  lower  end  of  the  main  vein 
under  each  leaf.  Through  this  opening,  on  warm  days,  the  plant  dis- 
charges any  excess  of  the  resinous  matter  which  circulates  through  its 
branches.  Before  the  plant  attains  its  full  height  it  begins  to  throw  off 
flower-stalks,  which  are  generally  (when  perfectly  formed)  small  in  diameter 
and  of  considerable  length;   on  the  extremity  of  these  stalks  the  blossom 


Fig.  161.— Cotton  Bells. 


pod  after  a  time  appears,  encased  in  three  leaf-sheaths  or  calyxes,  with 
fringes  of  various  lengths.  Gradually  this  pod  expands  until  it  attains 
to  about  the  size  of  a  bean,  when  it  bursts  and  displays  the  blossom.  This 
blossom  only  exists  in  full  development  for  about  twenty-four  hours,  when 
it  begins  to  revolve  imperceptibly  on  its  axis  and  in  about  a  day's  time 
twists  itself  completely  off.  When  the  blossom  has  fallen,  a  small  three- 
and,  in  some  cases,  five-celled  triangular  capsular  pod  of  a  dark-green 
color  is  disclosed,  which  increases  in  size  until  it  reaches  that  of  a  large 
filbert  (Figs.  161  and  162).  Meantime  the  seeds  and  filaments  have  been 
in  course  of  formation  inside  the  pod,  and  when  growth  is  completed  the 
expansion  of  the  fiber  causes  it  to  burst  into  sections,  in  each  cell  of  which, 
and  adhering  firmly  to  the  surface  of  the  seeds,  is  a  tuft  of  the  downy 
material." 


ORIGIN  AND  GROWTH 


365 


In  America,  India,  and  Egypt  the  cotton  plant  is  annual  in  its  growth, 
but  in  hot  tropical  climates,  and  in  South  America,  it  becomes  a  perennial 
plant  and  assumes  more  of  a  treelike  form. 

According  to  von  Humboldt,  that  portion  of  the  world  lying  between 
the  equator  and  the  34th  degree  of  latitude  presents  the  most  suitable 
conditions  for  the  cultivation  of  the  Gossypium  barbadense,  G.  hirsutum, 
and  G.  arboreum  cottons,  a  mean  yearly  temperature  of  68°  to  86°  F. 
being  required.  G.  herbaceum  is  best 
cultivated  in  zones  where  the  tem- 
perature in  winter  does  not  fall  below 
50°  F.,  nor  in  summer  rise  above 
77°  F.  In  the  United  States  the 
cotton  plant  is  cultivated  up  to 
37°  north  latitude,  but  the  best 
fiber  is  obtained  from  along  the 
eastern  coast  between  25°  10',  and 
32°  40'  north  latitude,  which  includes 
the  states  of  Florida,  Georgia,  and 
South  Carolina.  Proximity  to  the 
sea  appears  to  have  a  beneficial  in- 
fluence on  the  quality  of  the  cotton 
fiber,  due,  no  doubt,  to  the  salt- 
laden  air  and  soil.  This  same  fact 
is  to  be  obsei'ved  in  Indian  and 
Egyptian  cottons.  In  fact,  the  only 
exception  to  this  rule  appears  to  be 
Brazilian  cotton,  that  from  the  in- 
land districts  being  of  superior 
quality  to  that  produced  along  the 
coast.  The  reason  for  this,  how-  Fig.  162.— Sections  of  the  Cotton  Boll 
ever,  is  that  the  coast  districts  of  (Egyptian).  (After  Witt.)  A,  Stem; 
Brazil  have  an  excessive  rainfall  5,  calyx;  C,  capsule;  Z),  seed;  £,  cotton 
during  nearly  nine  months  of  the 
year.     In  China  and  Japan  cotton  is 

cultivated  readily  as  far  north  as  41°,  and  in  Europe  (Black  Sea  provinces) 
its  cultivation  reaches  to  46°. 

The  leaf  of  the  cotton  plant  has  three-pointed  lobes;  the  flower  has 
five  petals,  yellow  at  the  base,  but  becoming  almost  white  at  the  edges. 
The  fruit  of  the  cotton  plant  forms  the  cotton  boll,  which  contains  the 
seeds  with  the  attached  fibers.  The  cotton  fiber  is  developed  as  a  pro- 
tective covering  to  the  young  seeds  while  still  in  their  embryonic  condition. 
This  provision  is  not  restricted  to  the  cotton  plant  alone,  but  is  common 
to  many  other  species.     The  boll  consists  of  from  three  to  five  segments, 


366 


COTTON 


and  on  ripening  bursts  open  and  discloses  a  mass  of  pearly  white  downy 
fibers,  in  which  are  imbedded  the  brownish  black  to  black-colored  cotton- 
seeds. 


Fig.  163.— Pneumatic  Hiiller  Gin.     (Murray  Co.) 

The  time  required  for  the  maturity  of  cotton  is  divided  as  follows: 
From  seeding  to  flowering,  New  Orleans  80  to  90  days,  Sea-island  100  to 
110  days;  from  flowering  to  maturity,  New  Orleans  70  to  80  days,  and 
Sea-island  about  80  days,  making  the  total  period  of  growth  about  5  to 


COTTON   GINNING 


367 


6|  months.  The  cotton  should  be  picked  as  soon  as  possible  after  ripening; 
the  seeds  are  then  separated  from  the  fibers  by  a  process  known  as  ginning. 
3.  Cotton  Ginning. — Cotton  which  has  been  picked  from  the  plant 
and  still  contains  the  seed  is  known  as  "  seed  cotton."  Before  the  ginning 
process  proper  the  seed  cotton  is  often  passed  through  cleaners  for  the 
purpose  of  breaking  up  any  unopened  bolls  and  disintegrating  lumps  of 
dirt,  burrs,  etc.,  which  may  be  mingled  with  the  cotton  fibers.  The 
principle  on  which  the  ginning  depends  is  to  pull  the  fiber  through  a 


Fig.  164. — Long  Staple  Roller  Gin.     (Murray  Co.) 

narrow  space  which  is  too  small  to  permit  of  the  seed  following.  There 
are  two  types  of  cotton  gins,  the  roller  gin  and  the  saw  gin.  The  former 
is  only  used  for  long  stapled  cottons  where  the  chief  consideration  is  to 
preserve  the  length  of  the  fiber.  It  has  a  much  lower  production  in  a 
given  time  than  the  saw  gin.  The  latter  was  the  invention  of  Eli  Whitney, 
and  is  still  the  same  in  principle  as  when  first  invented  in  1793.  Briefly 
described,  the  saw  gin  consists  of  a  box  or  hopper  for  holding  the  seed 
cotton;  one  side  of  this  box  is  a  grate  composed  of  steel  bars,  through 
the  intervals  of  which  a  number  of  thin  steel  discs,  notched  on  the  edge 


368 


COTTON 


(saws),  rotate  rapidly.  The  fibers  are  caught  in  the  notches  or  teeth  of 
these  discs  and  thus  pulled  from  the  seeds,  the  latter  as  they  are  cleaned 
fall  down  through  a  slit  below  the  grate.  The  fibers  are  carried  off  the 
revolving  saws  by  means  of  a  rapidly  rotating  cylindrical  brush.  The 
cotton  fiber  as  ginned  from  the  seed  is  technically  known  as  "  lint."  In 
upland  or  ordinary  American  cotton,  the  seeds  are  not  entirely  freed 
from  fiber  by  the  ginning,  there  remaining  more  or  less  short  fiber  together 
with  a  fine  undergrowth  of  fiber,  amounting  on  an  average  to  about  10 
percent  of  the  total  weight  of  the  seed.  At  the  present  time  these  seeds 
are  further  delinted  by  passing  through  specially  constructed  gins  having 


Fig.  165. — Linter  Gin.     (Carver  Cotton  Gin  Co.) 

saw-teeth  closer  set  and  finer.  The  fiber  obtained  in  this  manner  is  known 
as  "  linters,"  and  is  chiefly  used  for  cotton-batting  or  is  converted  into 
guncotton. 

4.  Constituents  of  Cotton  Plant. — Besides  the  fiber  itself,  nearly  all 
of  the  other  products  of  the  cotton  are  now  utilised  commercially.  The 
seeds  are  of  especial  value,  as  they  contain  a  large  quantity  of  oil,  which 
is  expressed  and  used  for  soapmaking  and  many  other  purposes,  while  the 
residuum  of  meal  and  hulls  is  converted  into  cattle  foods  and  fertiliser. 

The  following  table  presents  the  fertilising  constituents  in  a  crop  of 
cotton  yielding  100  lbs.  of  lint  per  acre,  expressed  in  pounds  per  acre. 
The  weight  of  the  total  crop  from  the  acre  was  847  lbs. 


CONSTITUENTS  OF   COTTON   PLANT 


369 


Part  of  Plant. 

Nitrogen. 

Phosphoric 
Acid. 

Potash. 

Lime. 

Magnesia. 

Roots  (83  lbs ) 

0.76 
3.20 
6.16 
3.43 
6.82 
0.34 

0.43 
1.29 

2.28 
1.30 

2.77 
0.10 

1.06 
3.09 
3.46 
2.44 
2.55 
0.46 

0.53 
2.12 
8.52 
0.69 
0.55 
0.19 

0  34 

Stems  (219  lbs.) 

Leaves  (192  lbs.) 

Bolls  (135  lbs.) 

0.92 
1.67 
0.54 

Seed  (218  lbs.) 

1.20 

Lint 

0.08 

Total  (847  lbs.) 

20.71 

8.17 

13.06 

12.60 

4.75 

According  to  Bulletin  No.  33  (U.  S.  Dept.  Agric.)  the  following  is  the 
proportion  of  the  different  parts  of  the  cotton  plant,  calculated  on  the  dried 
or  water-free  material : 


Part  of  the  Plant. 

Weight. 

Percent. 

Ounces. 

Grams. 

Roots 

0.513 

14.55 

8.80 

Stems 

1.350 

38.26 

23.15 

Leaves 

1.181 

33.48 

20.25 

Bolls 

0.829 

23.49 

14.21 

Seed 

1.343 

38.07 

23.03 

Lint  (fiber) 

0.615 

17.45 

10.56 

Total 

5.831 

165.30 

100.00 

This  table  was  compiled  from  the  examination  of  a  large  number  of 
plants  and  represents  the  average  composition  of  the  cotton  plant  as  stated. 

The  following  table  presents  the  proximate  percentage  constituents  of 
the  various  parts  of  th(!  cotton  plant  as  given  by  analyses  of  a  large  number 
of  samples  by  the  United  States  Department  of  Agriculture : 


Nitrogen- 

Part  of  Plant. 

Water. 

Ash. 

Protein. 

Fiber. 

free 
Extract. 

Fat. 

Entire  plant 

10.00 

12.01 

17.57 

22.04 

35.11 

4.15 

Roots 

10.00 

7.23 

9.89 

48.57 

39.15 

2.77 

Stems 

10.00 

9.64 

20.45 

49.44 

39.87 

3.50 

Leaves 

10.00 

12.87 

21.64 

12.57 

36.82 

6.05 

Bolls 

10.00 

4.90 

15.89 

19.72 

45.42 

4.07 

Seed 

9.92 

4.74 

19.38 

22.57 

23.94 

19.45 

Lint 

6.74 

1.65 

1.50 

83.71 

5.79 

0.61 

370  COTTON 

The  following  table  shows  the  products  obtainable  from  2000  lbs.  of 
cotton-seed : 

A.  Linters,  27  lbs. 

B.  Hulls,  841  lbs. 

1.  Bran,  Feeding  stuffs. 

2.  Fiber,  High-grade  paper. 

3.  Fuel,  Ashes  and  fertiliser. 

C.  Meats,  1012  lbs. 

1.  Cake,  732  lbs. 

(a)  Meal. 

(1)  Feeding  stufif. 

(2)  Fertilizer. 

2.  Crude  oU,  280  lbs. 

(a)  Soap  stock,  soaps. 

(b)  Summer  yellow. 

(1)  Winter  yellow. 

(2)  Salad  oil. 

(3)  Cotton  lard. 

(4)  Cottolene. 

(5)  Miner's  oil. 

(6)  Soap. 

An  Experiment  Station  Report  shows  that  the  seeds  from  upland 
cotton  after  ginning  consist  of  54.22  percent  of  kernels  (yielding  36.88 
percent  of  oil  and  63.12  percent  of  meal)  and  45.78  percent  of  hulls  (yielding 
27.95  percent  of  linters  and  72.05  percent  residue;  so  that  in  the  ginned 
seed  there  is  present  the  following: 

Percent. 

Meal 34.22 

OU 20.00 

Hulls 35.78 

Linters 10.00 

According  to  Adriane  ^  the  seeds  from  Egyptian  cotton  yield  37.45 
percent  of  hulls  and  62.55  percent  of  kernels. 

5.  Cotton  Linters. — The  short  fibers,  or  nep,  left  on  the  seed  after  the 
first  ginning  are  also  recovered  by  a  second  process  and  are  known  as 
linters;  they  are  used  in  the  manufacture  of  cotton  batting,  guncotton,  etc. 
With  Sea-island  and  Egyptian  cottons  the  seed  is  entirely  freed  from  lint 
by  ginning,  but  with  upland  cottons  the  quantity  of  lint  still  adhering 
to  the  seed  after  it  has  passed  through  the  gin  amounts  to  about  10  percent 
of  the  total  weight  of  the  seed. 

According  to  Kress  and  Wells  -  cottonseed  in  the  form  in  which  it  is 
delivered  to  the  mills  contains  about  200  lbs.  of  adherent  fiber  per  ton 
(2000  lbs.).     The  first  cut  yields  about  75  lbs.  of  linters  of  a  suitable 

^Chem.  News,  Jan.,  1865. 

2  Pulp  and  Paper  Mag.,  1919,  p.  697. 


PHYSIOLOGY  OF   COTTON   FIBER 


371 


length  for  use  as  a  stuffing  material ;  a  second  cut,  made  with  carborundum 
wheels  or  plates,  yields  75  to  100  lbs.  of  linters,  practically  free  from 
hull  particles  and  easily  purified  for  paper-making;  after  decortication,  the 
residual  hull  fibers  are  treated  in  steel  attrition  mills  and  yield  very  spccky 
shavings.  The  average  length  of  the  linters  fiber  is  4.62  mm.,  while  the 
average  length  of  the  hull  shavings  fiber  is  2.41  mm. 

The  separation  of  seed-particles  from  the  fiber  is  not  always  perfect, 
and  frequently  these  particles,  make  their  appearance  in  gray  calico  in 
the  form  of  black  specks  or  motes,  and  as  they  contain  small  quantities  of 
oil  and  tannin  matters  which  are  pressed  out  into  the  sm-rounding  fibers, 
they  cause  specks  and  unevenness  in 
dyeing  and  finishing.  If  they  come 
in  contact  with  solutions  or  mate- 
rials containing  iron  compounds,  a 
violet  stain  will  be  produced,  the 
color  of  which,  however,  may  not 
develop  for  some  months. 

6.  Physiology  of  Cotton  Fiber. 
— The  development  of  the  cotton 
fiber  from  the  seed  is  as  follows: 
"If  a  very  immature  cotton  boll 
be  cut  transversely,  the  cut  sec- 
tion will  show  that  it  is  divided 
by    longitudinal    walls    into    three 

or   more   divisions,   and   the  seeds  j^     -.m     t.     •    i  r^  +.     t?u         r-^onn\ 
'  1*  iG.  166. — Typical  Cotton  Fibers.     ( X300.) 

will     be     shown     attached     to     the       a,  Normal  fiber  showing  regular  twists; 
inner  angle  of  each  division.     The      B,  straight   fiber  without  twists;   C,  a 
seeds  retain    this  attachment  until       knot  or  irregularity  in  growth  of  fiber, 
they    have     nearly    reached    their      (Micrograph  by  author.) 
mature  size  and  the  growth  of  lint 

has  begun  on  them,  when  their  attachments  begin  to  be  absorbed,  and 
by  the  increased  growth  of  the  lint  the  seeds  are  forced  into  the  center 
of  the  cavity.  The  development  of  the  fiber  commences  at  the  end 
of  the  seed  farthest  from  its  attachment  and  gradually  spreads  over  the 
seed  as  the  process  of  growth  continues.  The  first  appearance  of  the 
cotton  fiber  occurs  a  considerable  time  before  the  seed  has  attained  its 
full  growth  and  commences  by  the  development  of  cells  from  the  surface 
of  the  seed.  These  cells  seem  to  have  their  origin  in  the  second  layer 
of  cellular  tissue,  and  force  themselves  through  the  epidermal  layer,  W'hich 
seems  to  be  gradually  absorbed.  The  cells  which  originate  the  fiber  are 
characterised  by  the  thickness  of  their  cell-walls  when  compared  with 
their  diameter."^ 

1  Bulletin,  No.  33. 


372 


COTTON 


Bowman  gives  an  excellent  description  of  the  physiological  develop- 
ment of  the  cotton  fiber,  from  which  the  following  is  quoted:  "  In  their 
earliest  stages  the  young  cotton  fibers  appear  to  have  a  circular  section 
arising  from  the  comparative  thickness  of  the  tube-walls;  but  as  these 
walls  gradually  become  thinner  by  the  longitudinal  growth  of  the  hair 
and  the  pressure  to  which  they  are  subjected  by  the  contact  of  surrounding 
fibers  enclosed  within  the  pod,  they  gradually  become  flattened,  and  just 
before  the  pod  bursts  the  outer  walls  of  the  cells  have  become  so  attenuated 
in  the  longest  fibers  as  to  be  almost  invisible  even  under  high  microscopic 
powers,  and  present  the  appearance  of  a  thin,  pellucid,  transparent  ribbon. 
With  the  bursting  of  the  pod,  however,  a  change  occurs.     The  admission 

of    air    and    sunlight    causes   a 
gradual  unfolding  of    the   hairy 
plexus,  and  the  rapid  consolida- 
tion of  the  liquid  cell-contents  on 
the  inner  surface  of  the  cell-wall 
gives  them  a  greater  thickness  and 
density,  which  is  further  increased 
by  the  gradual  shrinking  in  of  the 
walls  themselves  upon  the  cell- 
contents.     There  is  also  a  gradual 
rounding  and  thickening   of   the 
fiber,  which  increases  by  the  de- 
position of  matter  on  the  inner 
wall  of  the  cell.  As  this  action  is 
not  perfectly  uniform,  arising  from 
Fig.  167.— Typical  Cotton  Fibers.     (X300.)   the  unequal  exposure  of  different 
A,   Broad    flat    fiber    near  base;    B,   thick    parts  of  the  fibers  to  light  and  air, 
rounded  fiber;  C,  fiber  near  pointed  end;  D,    H  causes  a  twisting   of  the  hairs, 
cut  end  of  fiber.    (Micrograph  by  author.)    ^j^j^j^    jg  always  a  characteristic 

of  cotton  when  viewed  under  the 
microscope,  and  the  flat  collapsed  portions  of  the  tube  form  so  many 
reflecting  surfaces,  to  which  the  brightness  of  the  fiber  when  stretched 
tight  in  the  fingers  is  no  doubt  due.  Another  change  also  occurs  at  this 
stage,  a  change  which  corresponds  to  the  ripening  of  fruit.  In  the  earliest 
period  of  their  formation  the  growing  cells  are  filled  with  juices  which 
are  more  or  less  astringent  in  character.  Under  the  influence  of  light 
and  air  these  cell-contents  undergo  a  chemical  change,  in  which  the 
astringent  principles  are  replaced  by  more  or  less  saccharine  or  neutral 
juices,  until  in  the  perfectly  ripe  cotton  fiber  the  cell- walls  are  composed 
of  almost  pure  cellulose." 

Flatters  ^  gives  a  detailed  description  of  the  physiology  of  the  cotton 
1  The  Cotton  Plant,  p.  59.     A  very  complete  description  of  the  physiology  of  the 
entire  cotton  plant  is  also  given  in  this  book,  see  pp.  17,  et  seq. 


CONDITIONS  AFFECTING  QUALITY  OF  FIBER  373 

fiber,  from  which  the  following  is  adapted:  Soon  after  the  fertilisation  of 
the  ovum  of  the  flower  certain  structural  differences  begin  to  appear  in 
the  cuticle  cells  forming  the  wall  of  the  ovary.  A  thin  laj'er  of  protoplasm 
is  soon  formed  around  the  inner  wall  of  the  cell.  Intervening  cells  begin 
to  elongate  until  the  entire  surface  of  the  ovule  presents  the  appearance 
of  being  covered  with  minute  protuberances.  These  continue  to  elongate 
until  a  definite  fibril  covering  is  attained.  At  the  commencement  of  this 
cuticular  differentiation  the  underlying  tissue  is  gorged  with  protoplasm, 
in  which  food  substances  are  imbedded,  but  wliich  soon  become  absorbed 
by  the  developing  fibers.  This  fibril  development  is  coincident  with  the 
formation  and  development  of  the  embryo,  and  serves  as  a  protective 
covering  for  it.  In  addition  to  the  protoplasm  and  nucleus  there  are 
found  in  the  cotton  fiber  during  its  development  and  its  maturity  minute 
microscopic  bodies,  the  endochrome.  The  presence  of  the  endochrome  is 
more  emphasised  in  wild  cottons  than  in  the  cultivated  species.  On  this 
account  the  fiber  of  nearly  all  wild  cotton  plants  has  a  deep  rusty  tint 
{Khaki  or  red  cotton).  Watt  ^  states  that  so  very  constant  is  this  peculiar- 
ity of  the  uncultivated  cottons,  that  its  appearance  in  the  field  ma}'  be 
accepted  as  an  almost  certain  sign  of  a  low-grade  plant,  or  of  defective 
cultivation,  or  unsuitable  environment.  It  is  in  all  probability  a  sign  of 
"  reversion  "  to  an  ancestral  and  presumably  hardier  or  more  prepotent 
condition.  The  presence  or  absence  of  the  endochrome  determines  the 
color  of  the  fiber,  which  in  some  types  becomes  definite  by  imparting  to 
it  a  deep  brown  color,  as  in  "  brown  Egyptian,"  and  a  still  deeper  color, 
as  in  "  red  Peruvian."  Endochrome  is  found  more  or  less  in  every  class 
of  cotton.  It  does  not,  except  in  a  few  cases,  permeate  the  cell-wall  of 
the  fiber,  but  becomes  coagulated  as  the  fiber  matures,  and  forms  a  central 
core  in  the  fibril  cavity.  It  is  this  core  which  imparts  to  the  fiber  its 
color  by  reflection  through  the  transparent  cell-wall. 

Flatters  concludes  that  the  cotton  fiber  is  made  up  of  three  primary 
elements,  (a)  the  cuticular  envelope ;  (6)  the  secondary  deposit  of  cellulose ; 
(c)  the  endochromic  coloring  matter. 

The  cell-wall  of  the  cotton  is  thin  in  comparison  with  that  of  the 
bast  fibers,  but  in  comparison  with  the  other  seed-hairs  it  is  remarkably 
thick.  This  accounts  for  its  much  greater  strength  over  the  latter.  In 
completely  developed  fibers  the  thickness  of  the  cell-wall  is  from  one-third 
to  two-thirds  of  the  total  thickness  of  the  fiber  itself. 

7.  Conditions  Affecting  Quality  of  Fiber. — The  quality  of  the  cotton 
fiber  depends  not  only  on  the  species  of  the  plant  from  which  it  is  derived, 
but  also  on  the  manner  of  its  cultivation.  The  conditions  which  exercise, 
perhaps,  the  greatest  influence  are:  (o)  the  seed,  (6)  the  soil,  (c)  the  mode 
of  cultivation,  {d)  the  climatic  conditions.  The  seed  for  sowing  must 
^  Wild  and  Cultivated  Cotton  Plants,  p.  28. 


374 


COTTON 


be  carefully  and  specially  chosen  for  the  purpose.  A  very  dry  soil  pro- 
duces harsh  and  brittle  cotton,  the  fibers  of  which  are  very  irregular  in 
length;  a  moist  and  sandy  soil  produces  a  very  desirable  cotton  of  long 
and  fine  staple.  The  best  soil  is  considered  to  be  a  light  loam,  while  a 
damp  clay  is  regarded  as  the  worst.  An  excess  of  rain  causes  the  plant 
itself  to  grow  too  rapidly  and  luxuriantly  at  the  expense  of  the  fruit  and 
consequently  there  is  less  fiber  produced.  A  long  drought  causes  a 
stunted  growth  of  the  plant,  but  few  bolls  are  produced,  and  these  ripen 
prematurely.  Soils  situated  in  proximity  to  the  sea,  and  therefore  con- 
taining considerable 
saline  matter,  appear 
to  furnish  the  most 
valuable  varieties  of 
cotton,  and  it  is 
claimed  that  the  sa- 
line constituents  of 
the  soil  have  consid- 
erable influence  on 
the  growth  and  de- 
velopment of  the 
cotton  fiber.  It  is 
said  that  the  best 
average  daily  tem- 
perature for  the 
growth  of  cotton  is 
from  60°  to  68°  F. 
for  the  period  from 
germination  to  flow- 
ering, and  from  68° 
to  78°  F.  from  flow- 
ering to  maturity. 
According  to  Dr. 
Wight,^  for  the  proper  maturing  of  the  best  qualities  of  American  cotton 
an  increasing  temperature  during  the  period  of  greatest  growth  is  required; 
the  failure  to  produce  in  India  a  quality  of  fiber  equal  to  the  American 
product  from  the  same  kind  of  seed  is  attributed  to  the  fact  that  in  the 
climate  of  the  former  country  there  exists  a  diminishing  rather  than  an 
increasing  average  daily  temperature.  Flatters  states  that  a  humid 
temperature  ranging  from  70°  upward,  and  a  soil  of  a  deep  loamy  nature 
in  which  alkaline  and  calcareous  salts  are  present,  and  which  contains  at 
least  3  percent  of  phosphoric  acid,  seem  to  be  the  most  suitable  conditions 
for  the  successful  cultivation  of  the  cotton  plant. 

^  Jour.  Agr.  Hort.  Soc.  India,  vol.  7,  p.  23.. 


Fig. 


168.— Sea-isJand  Cotton.     (X400.) 
author.) 


(Micrograph  by 


BOTANICAL  CLASSIFICATION  OF  COTTON  375 

8.  Botanical  Classification  of  Cotton. — The  classification  of  the  different 
species  of  cotton  plant  varies  with  different  authorities;  the  most  compre- 
hensive, perhaps,  is  to  classify  the  different  varieties  of  the  cotton  plant  as 
(1)  the  tree,  (2)  the  shrub,  and  (3)  the  herbaceous  species. 

The  following  is  a  list  of  species  of  the  cotton  plant  more  or  less  recog- 
ised  by  botanists: 

Gossypium  album  Hamilton,  a  synonym  of  G.  herbaceum;    commercially  known  as 

upland  cotton;  has  a  white  seed. 
G.  arbor eum  LLnn.,  a  tree-like  plant;   perennial;   indigenous  to  India;  produces  but 

little  fiber. 
G.  barbadense  Linn.,  indigenous  to  America  and  outlying  islands;   gives  the  highly 

prized  sea-island  cotton. 
G.  brasiliense  Macfad.,  a  tropical  species;  belongs  to  the  so-called  "kidney  cottons"; 

the  seeds  adhere  to  one  another  in  clusters. 
G.  chinense  Fisch  &  Otto,  a  synonym  for  G.  herbaceum;   a  Chinese  cotton. 
G.  croceum  Hamilton,  a  synonym  for  G.  herbacezmi;  possesses  a  yellow  lint. 
G.  eglandulosum  Cav.,  a  synonym  for  G.  herbaceum. 
G.  elatum  Salisb.,  a  synonym  for  G.  herbaceum. 
G.  fructescens  Lasteyr.,  a  synonym  for  G.  barbadense. 
G.  fuscum  Roxb.,  a  sjTionym  for  G.  barbadense. 
G.  glabrum  Lam.,  a  synonym  for  G.  barbadense. 
G.  glandidosum  Steud.,  a  synonym  for  G.  herbaceum. 
G.  herbaceum  Linn.,   usually  considered  of  Asiatic    origin;    synonymous  with  G. 

hirsutum;  ordinary  upland  cotton. 
G.  hirsutum  Linn.,  of  American  origin;   Georgia  upland  cotton. 
G.  indicum  Lam.,  a  synonym  for  G.  herbaceum. 

G.  jamaiccnse  Macfad.,  a  synonym  for  G.  barbadense;  grows  in  Jamaica. 
G.javanicum  Blume,  a  s>Tionym  for  G.  barbadense;  grows  in  Java. 
G.  kirkii  Masters,  a  wild  African  species  never  found  under  cultivation;    the  only 

known  variety  of  which  the  seed  is  left  quite  naked  by  removal  of  the  fibers. 
G.  latifolium  Murr.,  a  synonym  for  G.  herbaceum. 
G.  leoninum  Medic,  a  synonym  for  G.  herbaceum. 
G.  macedonicum  Murr.,  a  sjTionjon  for  G.  herbaceum. 
G.  maritimimi  Tod.,  a  synonym  for  G.  barbadense. 
G.  micranthum  Cav.,  a  synonjon  for  G.  herbaceum. 
G.  molle  Mauri,  a  synonym  for  G.  herbaceum. 
G.  nanking  Meyen,  a  synonym  for.  G.  herbaceum. 
G.  neglectum  Tod.,  indigenous  to  India;   similar  to  G.  arboreum;  extensively  grown 

in  India;  gives  the  Dacca  and  China  cottons. 
G.  nigrum  Hamilton,  a  sjTionym  for  G.  barbadense. 
G.  obtusifoliwn  Roxb.,  a  synonym  for  G.  herbaceum,  a  distinctly  Oriental  species  to 

be  met  with  in  India,  Ceylon,  etc. 
G.  oligospermum  Macfad.,  a  synonym  for  G.  barbadense. 
G.  paniculalmn  Blanco,  a  synonym  for  G.  herbaceum. 
G.  -perenne  Blanco,  a  synonym  for  G.  barbadense. 
G.  peruvianum  Cav.,  a  synonym  for  G.  barbadense. 
G.  punctaium  Schum.  &  Thonn.,  a  synonym  for  G.  barbadense. 
G.  racemosum  Poir,  a  synonym  for  G.  barbadense. 
G.  religiosum  Par.,  a  synonym  for  G.  arboreum;   so  called  because  its  use  is  mostly 

restricted  to  making  turbans  for  Indian  priests;   also  because  it  grows  in  the 


376  COTTON 

gardens  of  the  temples;   it  has  the  cultural  name  of  Nurma  or  Deo  cotton. 

Also  a  variety  of  G.  barbadense. 
G.  roxburghianum  Tod.,  a  variety  of  G.  neglectum;   corresponds  to  the  Dacca  cotton 

of  India. 
G.  siamense  Tenore,  a  synonym  for  G.  herbaceum. 
G.  sinense  Fisch.,  a  synonym  for  G.  herbaceum. 
G.  stocksii  Masters,  a  synonym  for  G.  herbaceum;   claimed  to  be  the  original  of  all 

cultivated  forms  of  this  latter  species. 
G.  strictum  Medic,  a  synonym  for  G.  herbaceum. 
G.  tomentosuvi  Nutt,  indigenous  to  the  Hawaiian  Islands  where  it  is  known  as  Mao 

or  Huluhulu  cotton;  the  bark  is  used  for  making  twine. 
G.  tricuspidatum  Lam.,  a  synonym  for  G.  herbaceum. 
G.  vitifolium  Lam.,  a  synonym  for  G.  barbadense. 
G.  vitifolium  Roxb.,  a  synonym  for  G.  herbaceum. 
G.  wighlianum  Tod.,  a  synonym  for  G.  herbaceum;    claimed  by  Todaro  to  be  the 

primitive  form  of  the  Indian  cottons.     It  furnishes  the  so-called  long-stapled 

or  gujarat  cotton  of  India. 

According  to  Parlatore  all  commercial  cotton  is  derived  from  seven 
species  of  the  Gossypium,  which  he  enumerates  as  follows : 

(1)  G.  barbadense  which  comprises  the  long-stapled  and  silky-fibered 
cottons  known  as  Barbadoes,  Sea-island,  Egyptian,  and  Peruvian} 

The  plant  reaches  a  height  of  from  6  to  8  ft.,  and  has  yellow  blossoms 
becoming  purple  toward  the  base.     The  seeds  are  small  in  size  and  of  a 

'  The  botany  of  this  species  is  given  as  follows:  Shrubby,  perennial,  6  to  8  ft- 
high,  but  in  cultivation  herbaceous  and  annual  or  biennial,  3  to  4  ft.  high,  glabrous, 
dotted  with  more  or  less  prominent  black  glands.  Stems  erect,  terete  branching. 
Branches  graceful,  spreading,  subpyramidal,  somewhat  angular,  ascending,  at  length 
recurving.  Leaves  alternate,  petiolate,  as  long  as  the  petioles,  rotund,  ovate,  sub- 
cordate,  3-  to  5-lobed,  sometimes  with  some  of  the  upper  and  lower  leaves  entire, 
cordate,  ovate,  acuminate;  lobes  ovate,  ovate-lanceolate,  acute  or  acuminate,  chan- 
neled above,  sinus  subrotund,  above  green,  hghter  on  the  veins,  glabrous,  beneath 
pale  green  and  glabrous,  3-  to  5-veined,  the  mid-vein  and  sometimes  one  or  both  pairs 
of  lateral  veins  bearing  a  dark-green  gland  near  their  bases.  Stipules  erect  or  spreading, 
curved,  lanceolate-acuminate,  entire  or  somewhat  laciniate.  Peduncles  equal  to  or 
shorter  than  the  petiole,  erect,  elongating  after  flowering,  rather  thick,  angled,  some- 
times bearing  a  large  oval  gland  below  the  involucre.  Involucre  3-parted,  erect, 
segments  spreading  at  top,  many  veined,  broadly  cordate-ovate,  exceeding  half  the 
length  of  the  corolla,  9  to  12  divided  at  top,  divisions  lanceolate-acuminate.  Calyx 
much  shorter  than  the  involucre,  bracts  cup-shaped,  slightly  5-toothed  or  entire. 
Corolla  longer  than  the  bracts.  Petals  open,  but  not  widely  expanding  after  flower- 
ing, broadly  obovate,  obtuse,  crenate,  or  undulate  margined,  yellow  or  sulfur  colored, 
with  a  purple  spot  on  the  claw,  all  becoming  purplish  in  age.  Stamen  about  half  the 
length  of  the  corolla,  the  tube  naked  below,  anther  bearing  above.  Style  equal  to  or 
exceeding  the  stamens,  3-  to  5-parted.  Ovary  ovate,  acute,  glandular,  3-,  rarely  4-  to 
5-celled.  Capsule  a  little  longer  than  the  persistent  involucre,  oval,  acuminate,  green, 
shining,  3-,  rarely  4-  to  5-valved.  Valves  oblong  or  ovate-oblong,  acuminate,  the  points 
widely  spreading.  Seeds  6  to  9  in  each  cell,  obovate,  narrowed  at  base,  black.  Fiber 
white,  3  to  4  or  more  times  the  length  of  the  seed,  silky,  easily  separable  from  the 
seed.     Cotyledons  yellowLsh,  glandular,  punctate. 


BOTANICAL  CLASSIFICATION  OF  COTTON 


377 


black  color,  and  are  particularly  distinguished  from  those  of  ordinary 
American  cotton  in  that  they  do  not  possess  a  fine  undergrowth  of  short 
hairs  (neps);  consequently  when  ginned  the  seed  comes  out  clean  and 
smooth.  Owing  to  variations  in  the  conditions  of  its  cultivation,  however, 
the  present  Sea-island  cotton  has  changed  considerably  from  the  original 
barbadense.  The  following  species  are  considered  as  synonyms  of  G.  bar- 
badense:  G.  fructescens  Lasteyr.,  G.  fuscum  Roxb.,  G.  glabrium  Lam., 
G.  jamaicense  Macfad.,   G.  javanicum  Blume,    C.   maritimum  Todaro, 


l(o..S49.     LjEtvr    H.   'l>e*ey.    Oct. 14.     lao 


Fig.  169. — Cotton  Boll  and  Leaf,  Gossypium  Barbadense.     (Watt.) 


G.  nigrum  Ham.,  G.  oligospermum  Macfad.,  G.  -perenne  Blanco,  G.  peruvi- 
anum  Cav.,  G.  pundatum  Schum.  &  Thonn.,  G.  racemosum  Poir.,  G. 
religiosum  Par.,  and  G.  vitigolium  Roxb. 

Georgia  uplands  or  boweds  cotton  is  presumably  a  variety  of  this  species 
modified  by  cultivation  on  the  mainland.  This  variety  is  employed 
especially  for  the  spinning  of  fine  yarns.  Pima  cotton  is  a  long  stapled 
variety  grown  in  the  Salt  River  Valley  and  the  Yuma  Valley  of  Arizona. 
It  is  cultivated  especially  for  use  in  tire  fabrics. 


378  COTTON 

(2)  G.  herhaceum,  including  most  of  the  cotton  from  India,  southern 
Asia,  China,  and  Italy.^  Parlatore  claims  that  this  species  originated 
in  India,  while  Todaro  says  that  it  is  spontaneous  in  Asia  and  perhaps 
also  in  Egypt,  and  that  G.  wightianurn  is  the  primitive  form  of  the  Indian 
cottons;  others  still  consider  it  as  a  native  of  Africa.  According  to 
Bulletin  No.  33  (U.  S.  Dept.  Agric),  it  is  probable  that  G.  herhaceum  is 
not  a  definite  species,  but  has  been  developed  by  cultivation  from  perhaps 
several  wild  species,  and  it  represents  not  a  species  but  a  group  of  hybrids 
and  forms  more  or  less  closely  related.  The  following  species  are  con- 
sidered as  synonyms  of  G.  herhaceum:  G.  alhum  Ham.,  G.  chinense  Fisch., 
G.  croceum  Ham.,  G.  eglandulosum  Cav.,  G.  datum  Salis.,  G.  glandulosum 
Steud.,  G.  hirsutum  Linn.,  G.  indicum  Lam.,  G.  latifolium  Murr.,  G.  leoninum 
Medic,  G.  macedo7iicum  Murr.,  G.  micranthum  Cav.,  G.  inolle  Mauri, 
G.  nanking  Meyen,  G.  ohtusifolium  Roxb.,  G.  paniculatum  Blanco,  G.  punc- 
tatum  Guil.,  G.  religiosum  Linn.,  G.  siamense  Tenore,  G.  dnense  Fisch., 
G.  strictum  Medic,  G.  tricuspi datum  Lam.,  and  G.  vitifolium  Roxb. 

The  herhaceum  is  an  annual  plant  growing  from  5  to  6  ft.  in  height; 
unlike  the  harhadense  variety,  its  seeds  are  generally  covered  with  a  soft 
undergrowth  of  fine  down  which  is  an  objectionable  feature.  The  flower 
is  yellow  in  color  with  a  purplish  spot  at  the  base.     This  species  is  perhaps 

^  The  descriptive  botany  of  this  species  is  as  follows :  Shrubbj'^,  perennial,  but  in 
cultivation  herbaceous,  annual  or  biennial.  Pubescence  variable,  part  being  long, 
simple  or  stellate,  horizontal  or  spreading,  sometimes  short,  stellate,  abundant,  or 
the  plants  may  be  hirsute,  silky,  or  all  pubescence  may  be  more  or  less  wanting,  the 
plants  being  glabrous  or  nearly  so.  Glands  more  or  less  prominent.  Stems  terete, 
or  somewhat  angular  above,  branching.  Branches  spreading  or  erect.  Leaves  alter- 
nate, petioled,  the  petioles  about  equaling  the  blades,  cordate  or  subcordate,  3-  to  5-, 
rarely  7-lobed.  Lobes  from  oval  to  ovate,  acuminate,  pale  green  above,  lighter  beneath, 
more  or  less  harry  on  the  vein,  3-  to  5-  or  7-veined,  the  midvein  and  sometimes  the 
nearest  lateral  veins  glandular  toward  the  base  or  glands  wanting.  Sinus  obtuse. 
Lower  leaves  sometimes  cordate,  acuminate,  entire,  or  slightly  lobed.  Stipules  erect 
or  spreading,  ovate-lanceolate  to  linear-lanceolate,  acuminate,  entire,  or  occasionally 
somewhat  dentate.  Peduncles  erect  in  flower,  becoming  pendulous  in  fruit.  Involucre 
3-,  rarely  4-parted,  shorter  than  the  corolla,  appressed,  spreading  in  fruit,  broadly 
cordate,  incisely  serrate,  the  divisions  lanceolate-acuminate,  entire  or  sometimes 
sparingly  dentate.  Calyx  less  than  half  the  length  of  the  involucre  cup-shaped,  dentate, 
with  short  teeth.  Petals  erect,  spreading  obovate  or  cuneate,  obtuse  or  emarginate, 
curled  or  crenulate,  white  or  pale  yellow,  usually  with  a  purple  spot  near  the  base,  in 
age  becoming  reddish.  Stamens  half  the  length  of  the  corolla.  Pistil  equal  or  longer 
than  the  stamens.  Ovary  rounded  obtuse  or  acute,  glandular,  3-  to  5-celled.  Style 
about  twice  the  length  of  the  ovary,  3-  to  5-parted  above,  the  glandular  portion  often 
marked  with  2  rows  of  glands.  Capsule  erect,  globose  or  ovate,  obtuse  or  acuminate, 
mucronate,  pale  green,  3-  to  5-celled.  Valves  ovate  to  oblong,  with  spreading  tips. 
Seed  5  to  11  in  each  cell,  free,  obovate  to  subglabrous,  narrowed  at  base,  clothed  with 
two  forms  of  fiber,  one  short  and  dense,  closely  enveloping  the  seed,  the  other  2  to  3 
times  the  length  of  the  seed,  white,  silky,  and  separating  with  some  diflaculty.  Coty- 
ledons somewhat  glandular  punctate. 


BOTANICAL  CLASSIFICATION  OF  COTTON 


379 


the  hardiest  of  the  cottons  and  is  cultivated  over  a  wider  range  of  latitude. 
It  forms  the  source  of 
nearly  all  the  Indiai 
cotton,  as  well  as  the 
buff-colored  Nankin 
cotton  of  China,  and 
the  short-stapled  va- 
rieties of  Egyptian  and 
Smyrna  cottons.  It  is 
used  for  the  spinning 
of  low-count  yarns, 
also  for  the  making  of 
condenser  yarns  for 
the  manufacture  of 
flannelettes. 

Todaro  claims  that 
the  species  G.  wighti- 
anum  is  the  form  chief- 
ly cultivated  in  India. 
It  differs  from  the 
general  form  of  G. 
herhaceum  in  that  the 
latter  has  broader  and 
more  rounded  leaves, 
and  broader,  thinner, 
and  deeper  cut  brac- 
teoles.i 

There  is  another 
very  similar  form  indi- 
genous to  India  known 
as  G.  neglectufn;  it 
grows  as  a  large  bush, 
and  its  fiber  constitutes  the  majority  of  the  commercial  Bengal  cotton.^ 

^  The  botany  of  G.  inghlianuvi  is  as  follows:  Stems  erect,  somewhat  hairy,  branches 
spreading  and  ascending.  Leaves,  when  young,  densely  covered  with  short  thick, 
stellate  hairs,  becoming  nearly  glabrate  in  age;  ovate-rotund,  scarcely  cordate,  3- 
to  5-,  rarely  7-lobed;  lobes  ovate,  oblong,  acute,  constricted  at  base  into  a  rounded 
sinus.  Stipules  on  the  peduncles  almost  ovate,  others  Imear-lanceolate,  acuminate. 
Flowers  yellow  with  a  deep  purple  spot  at  base,  becoming  reddish  on  the  outside  in 
age.  Bracteoles  small,  slightly  united  at  base,  ovate,  cordate,  acute,  shortly  toothed. 
Peduncles  erect  in  flower,  recurved  in  fruit,  one-quarter,  the  length  of  the  petioles. 
Capsule  small,  ovate,  acute,  4-celled,  with  8  seeds  in  each  cell.  Seeds  small,  ovate, 
subrotund,  clothed  with  two  forms  of  fiber,  the  inner  short  and  closely  adhering,  the 
other  longer,  white  or  reddish. 

2  Its   botany   is  as  follows:    Stem   erect.     Branches  slender,    graceful   spreading. 


Fig.  170. — Gossypium  Herhaceum.     (Watt.) 


380 


COTTON 


Notwithstanding  the  inferiority  of  Indian  to  American  cotton,  the 

Dacca  spinners  can 
to-day  i)roduce  from 
what  is  considered  a 
very  poor  cotton 
staple  a  yarn  quite  as 
f.ne  as  that  made  in 
England  and  America 
from  the  finest  and 
best  staples.  This 
remains  one  of  the 
enigmas  of  the  cotton 
industry,  and  it  would 
seem  that  the  hand 
spinners  can  accom- 
plish something  the 
machine  spinners  can- 
not. 

The  cultivated 
cottons  of  to-day  are 
far  different  from  the 
original  form  of  the 
G.  herhaceitm,  which 
gave  only  28  to  29 
percent  of  fiber,  with 
a  staple  20  to  300  mm. 
long.  The  propoi-tion 
of  fiber  has  been 
greatly  increased, 
reaching  as  high  as  CO 
and  even  40  percent 
in  some  varieties,  while 
the  length  of  staple 
has  increased  corre- 
spondingly, sometimes  reaching  fully  three  times  its  original  length. 
Leaves,  lower  ones  5  to  7  palmately  lobed,  segments  lanceolate,  acute,  rarely  bristle- 
tipped,  sinus  rounded,  the  small  lobes  in  the  sinuses  less  distinct  than  in  G.  arboreum, 
upper  leaves,  3-parted.  Stipules  next  the  peduncles  semiovate,  dentate,  the  others 
linear-lanceolate,  acute.  Peduncles,  with  short  lateral  branches,  2  to  4  flowered. 
Involucral  bracts  coalescent  at  base,  deeply  and  acutely  laciniate.  Petals  less  than 
twice  the  length  of  the  involucral  bracts,  obovate,  unequally  cuneate,  yellow,  with  a 
deep  purple  spot  at  base.  Stamen-tube  half  the  length  of  the  corolla,  naked  at  base. 
Capsule  small,  ovate,  acute,  cells  5-  to  8-seeded,  seed  obovate,  small,  clothed  with 
two  forms  of  fiber,  one  very  short,  closely  adherent,  and  of  an  ashy  green  color,  the 
other  longer,  rather  harsh,  white. 


Fig.  171. — American  Cotton;  G.  hirsutum.     (Watt.) 


BOTANICAL  CLASSIFICATION  OF  COTTON 


381 


The  vine  cotton  of  Cuba  belongs  to  the  G.  herhaceum  species,  and  is 
peculiar  because  of  its  large  pods  and  excessive  number  of  seeds. 

(3)  G.  hirsutum,  including  most  of  the  cotton  from  the  southern 
United  States  also  known  as  upland  or  peeler  cotton.  American  or  main- 
land cotton  is  the  typical  cotton  of  the  world.  It  is  grown  in  the  American 
cotton  belt  which  ex- 
tends from  southeast 
Virginia  to  Texas. 
This  cotton  is  suited 
for  all  numbers  of 
yarn  up  to  50's  warp 
and  80's  filling,  being 
clean,  regular  in  length 
of  staple  and  well 
graded.  On  account 
of  these  features,  as 
well  as  the  fact  that 
the  quantity  raised  is 
greater  than  all  the 
other  cotton  of  the 
world,  the  price  of 
American  cotton  regu- 
lates the  price  of  cot- 
ton throughout  the 
world.  Of  this  Ameri- 
can cotton,  the  Gulf 
(New  Orleans),  Ben- 
ders, or  Bottom  Land 
varieties  are  the  most 
important,  varying  in 
length  from  1  to  If 
ins.  Cotton  sold  in 
the  market  as  Mobile, 
Peelers,  and  Allen-seed 
belong  to  the  same 
variety  and  are  next  in 
importance;  while  Mississippi,  Louisiana,  Selina,  Arkansas,  and  Memphis 
cottons  are  slightly  inferior.  Texas  cotton  varies  from  |  to  1  in.  in  length 
and  is  suitable  for  warp  yarns  up  to  32's.  Next  in  importance  is  the  upland 
cotton,  having  a  length  of  |  to  1  in.  and  suitable  for  spinning  into  30's 
filling.  Cottons  sold  under  the  names  of  Georgia,  Boweds,  Norfolk,  and 
Savannah  also  belong  to  the  upland  variety. 

The  cotton  plant  of  the  Southern  States  is  a  small  annual  shrub  from 


Fig.  172.— Tree  Cotton;  G.  arboreum.     (Watt.) 


382 


COTTON 


2  to  4  ft.  in  height,  always  branching  extensively.  The  limbs  are  longest 
at  the  bottom  of  the  stalk,  and  short  and  light  at  the  top.  The  flowers 
are  white  or  pale  yellow  or  cream-colored  the  first  day,  becoming  darker 
and  redder  the  second  day,  and  fall  to  the  ground  on  the  third  or  fourth 
day,  leaving  a  tiny  boll  developed  in  the  calyx.  This  boll  enlarges  until 
maturity  when  it  is  not  unlike  the  size  and  shape  of  a  hen's  egg.    When 

matured,  the  boll 
cracks  and  opens  the 
three  to  six  compart- 
ments which  hold  the 
seed  and  the  lint. 

The  plant  of  G. 
hirsutum  is  shrubby  in 
appearance,  seldom 
reaching  more  than  7 
ft.  in  height ;  like  the 
preceding  variety,  the 
seeds  are  also  covered 
with  a  fine  under- 
growth of  down.  The 
flower  is  either  yel- 
lowish white  or  of  a 
faint  primrose  tint. 

Todaro  claims  that 
this  species  originated 
in  Mexico,  whence  it 
has  been  spread  by 
cultivation  throughout 
the  warmer  portions  of 
the  world ;  to  this  form 
he  also  ascribes  the 
Georgia  or  long- 
stapled  upland  cotton. 
Parlatore,  on  the  other 
hand,  considers  it  as 
indigenous  to  the 
islands  in  the  Gulf  of  Mexico  as  well  as  the  mainland,  and  that  all  green- 
seeded  cotton,  wherever  cultivated,  originated  from  this  form.  Under  culti- 
vation this  plant  varies  in  many  directions.  It  is  usualh^  a  coarse,  stunted, 
much-branched,  erect,  greenish  red,  dust-coated  bush  (this  peculiarity 
being  a  consequence  of  the  abundance,  length,  and  strength  of  the  hairs 
with  which  the  leaf  stalks,  etc.,  are  covered).  The  leaves  rapidly  lose  tJie 
habit  of  being  entire,  and  are  mostly  3-lobed,  or  as  a  result  of  luxuriant 


Fig.  173. — Red  Peruvian  Cotton;  G.  microcarpum.    (Watt.) 


BOTANICAL   CLASSIFICATION  OF  COTTON 


383 


cultivation,  become  partially  lobed. 
yellow  to  large  and 
yellow  with  a  purplish 
tinge.  The  fruit  is 
usually  4-celled,  and 
the  seeds  always  large, 
ovate,  truncate  on  one 
extremity,  and  with  a 
pronounced  fuzz, 
which  may  be  grayish, 
rusty  or  green  in  color.^ 
(4)  G.  arboreum,  in- 
cluding the  cotton 
from  Ceylon,  Ai-abia, 
etc.-  As  the  name  in- 
dicates, it  is  a  treelike 
plant,  and  grows  from 
12  to  18  ft.  in  height. 
The  fibers  are  of  a 
greenish  color  and 
very  coarse ;  its  flowers 
are  of  a  purple  color. 
A  synonym  of  this 
species  is  G.  religiosum; 
it  appears  to  be  indi- 
genous to  India.  The 
plant  is  perennial  and 
lasts  from  five  to  six 
years,  and  though  the 
fiber  is  fine,  silky, 
and  of  good  length, 
yet  there  is  but  little 


The  flowers  range  from  small  pale 


Tahiti  Cotton;  G.  Tahitense.     (Watt). 


'  Watt,  Wild  and  Cultivated  Cottons,  pp.  183,  184. 

^The  descriptive  botany  of  this  species  is  as  follows:  Shrubby,  perennial,  but  in 
cultivation  sometimes  annual  or  biennial;  tomentose,  with  two  forms  of  hairs,  one 
long  and  simple,  the  other  more  numerous,  shorter,  and  stellate;  glands  small,  scarcely 
prominent,  more  or  less  scattered.  Stem  erect,  terete,  very  branching.  Branches 
spreading,  terete.  Leaves  alternate,  petiolate,  with  petioles  a  little  shorter  than  the 
blade,  subcordate,  5-  to  7-lobed,  lobes  oblong-lanceolate  or  lanceolate-acuminate,  bristle- 
tipped,  scarcely  channeled  above;  sinus  obtuse,  often  with  a  small  lobe  in  some  of  the 
sinuses,  beneath  pale  green  and  softly  pubescent,  5-  to  7-veined,  the  mid-vein  and  often 
the  two  adjacent  ones  with  a  reddish-yellow  gland  near  their  base;  upper  leaves 
palmately  3-  to  5-  lobed,  lobes  short.  Stipules  erect,  spreading,  lanceolate-acuminate. 
Peduncles  axillary,  erect  before  and  spreading  or  horizontal  after  flowering  and  drooping 


384  COTTON 

of  it  produced.  No  varieties  of  this  species  are  grown  in  America  for 
commercial  purposes,  and  not  even  in  India,  where  it  is  principally 
cultivated,  is  it  a  very  valuable  type  of  cotton;  it  is  never  used  as  a 
field  crop.  It. is  commonly  known  as  tree  cotton  or  cotton  tree.  In  India 
its  cultivation  is  probably  more  ancient  than  that  of  any  other  cotton. 

(5)  G.  jperuvianum,  including  the  native  Peruvian  and  Brazilian  cottons. 
This  differs  from  other  varieties  of  cotton  in  that  it  is  a  perennial  plant; 
the  growth  from  the  second  and  third  years,  only,  however,  is  utilised. 

(6)  G.  tahitense,  found  chiefly  in  Tahiti  and  other  Pacific  islands. 

(7)  G.  sandimchense,  occurring  principally  in  the  Hawaiian  Islands. 
This  classification  is  claimed  to  include  all  the  commercial  varieties 

of  cotton;  it  is  probable,  however,  that  the  last  two  can  be  included 
under  the  barbadense  and  hirsutum  varieties,  as  they  possess  the  same 
characteristics  as  these  fibers. 

Dr.  Royle  reduces  the  number  of  species  of  the  cotton  plant  to  the 
following  four: 

(1)  Gossypium  arbor eum. 

(2)  "        herbaceum. 

(3)  "        barbadense. 

(4)  "        hirsutum. 

Other  authorities  on  the  botany  of  tne  cotton  plant  have  recognised 
many  more  species  than  those  above  described.  Agostino  Todaro  has 
described  52  varieties,  while  the  Index  Kewensis  records  42  distinct 
species  and  refers  to  88  others  which  it  classifies  as  synonyms.  Hamilton 
reduces  the  number  of  species  to  three — namely,  the  white-seeded,  black- 
seeded,  and  yellow-linted,  assigning  to  these  species  the  botanical  names 
album,  nigrum,  and  croceum.  The  chief  difficulty  experienced  in  the 
botanical  classification  of  the  cotton  plant  is  the  fact  that  it  hybridises 
very  readily  and  has  a  tendency  to  suffer  alteration  in  variety  with  change 

in  fruit,  about  three-fourths  the  length  of  the  petioles,  terete,  destitute  of  glands, 
1  to  2  usually  1-flowered,  jointed  above  the  middle,  bearing  a  small  leaf  and  two  stipules 
at  this  point.  Involucre  3-parted,  appressed  or  scarcely  spreading  at  summit,  many 
nerved,  broadly  and  deeply  cordate,  ovate-acuminate,  5  to  9,  rarely  3  dentate  or 
nearly  entire.  Calyx  much  shorter  than  the  bracts,  subglobose,  truncate,  crenulate 
or  subdentate,  with  a  large  gland  at  the  base  within  the  involucre.  Corolla  cam- 
panulate,  petals  erect,  or  spreading  broadly  cuneate,  subtruncate,  crisp  or  crenulate, 
purple  or  rose-colored,  with  a  large  dark  purple  spot  at  the  base.  Staminal  tube 
about  half  the  length  of  the  corolla.  Pistils  equally  or  a  little  longer  than  the  stamens; 
Ovary  ovate,  acute,  glandular,  usually  3-celled.  Style  a  little  longer  than  the  ovary, 
3-parted  without  glands.  Capsule  pendulous,  a  little  longer  than  the  persistent 
involucre,  .ovate,  rounded,  glandular,  3-  to  4-celled,  and  valved.  Valves  ovate,  oval, 
spreading,  mucronate-acuminate,  the  mucro  recurved.  Seed  5  to  6,  ovate,  obscurely 
angled,  black.  Fiber  two  forms,  one  white,  long,  overl-"inf?  a  dark  green  or  black 
down;  not  readily  separable  from  the  seed. 


COMMERCIAL  VARIETIES  OF  COTTON  385 

in  the  conditions  of  its  cultivation  or  variation  in  the  character  of  the  soil 
or  climate.  The  following  remarks  relative  to  the  subject  of  the  cross- 
fertilisation  of  cotton  are  given  in  Bulletin  No.  33  {vide  supra).  The 
flower  of  the  cotton  plant  is  so  large  and  develops  so  rapidly  that  cross- 
fertilisation  is  easily  secured.  Flowers  which  are  to  be  fertilised  should 
be  among  those  which  are  developed  early  in  the  season,  and  should  always 
be  those  on  healthy  and  vigorous  plants.  The  flowers  to  be  operated 
upon  should  be  selected  late  in  the  afternoon;  one  side  of  the  unopened 
bud  should  be  split  lengthwise  with  a  sharp  knife  having  a  slender  blade, 
and  the  stamens  removed.  The  anthers,  the  fertilising  parts  of  the 
stamens,  will  be  found  well  developed  and  standing  well  away  from  the 
pistil,  though  not  yet  so  matured  as  to  be  discharging  pollen.  These  can 
be  readily  separated  from  their  support  by  a  few  careful  strokes  of  the 
knife,  and  the  emasculated  flower  should  then  be  enclosed  in  a  paper 
bag  to  prevent  access  of  pollen  from  unknown  sources.  The  following 
morning  the  pistil  will  be  fully  developed  and  ready  to  receive  pollen. 
A  freshly  opened  flower  from  a  healthy  plant  of  the  variety  which  it  is 
desired  to  use  in  making  the  cross  is  picked  and  carried  to  the  plant  which 
was  treated  the  previous  evening,  the  bag  is  removed  from  the  prepared 
flower,  and  by  means  of  a  camel's-hair  brush  pollen  is  dusted  over  the 
end  and  upper  part  of  the  pistil.  The  paper  bag  is  then  replaced  and 
allowed  to  remain  two  days,  after  which  it  should  be  removed. 

In  Europe  cottons  are  graded  according  to  their  value  as  follows: 

1.  Long  Georgia.         4.  Louisiana.  7.  Short  Georgia. 

2.  Makko.  5.  Cayenne.  8.  Surat. 

3.  Pernambuco.  6.  New  Orleans.  9.  Bengal. 

Besides  the  varieties  of  cotton  above  enumerated,  which  are  practically 
all  which  find  any  important  commercial  application,  there  is  another 
plant  which  yields  a  fiber  somewhat  similar  to  cotton,  and  known  as  the 
silk-cotton  plant.  It  belongs  to  the  same  natural  order,  Malvacece,  as 
the  ordinary  cotton  plant,  but  is  of  a  different  genus,  being  Salmalia 
instead  of  Gossypium.  It  grows  principally  on  the  African  coast  and  in 
some  parts  of  tropical  Asia.  The  plant  is  rather  a  large  tree,  reaching 
from  70  to  80  ft.  in  height.  The  blossoms  are  red  in  color,  and  the  seeds 
are  covered  with  long  silky  fibers,  which  are  not  adapted,  however,  for 
spinning. 

9.  Commercial  Varieties  of  Cotton.— Although  fibers  from  the  different 
special  of  the  cotton  plant  all  possess  the  same  general  phj^'sical  appearance, 
nevertheless,  there  are  characteristic  features  in  each  worthy  of  careful 
observation.  Though  to  the  casual  observer  the  different  varieties  of 
cotton  fiber  look  more  or  less  alike,  there  is  nevertheless  great  differences 
in  qualities  and  properties,  and  these  must  be  carefully  recognised  by  the 


386 


COTTON 


manufacturer  who  must  select  arid  grade  his  stock  with  reference  to  the 
nature  of  the  yarn  he  is  to  spin.  It  requires  a  highly  trained  and  experi- 
enced judge  to  properly  grade  the  different  qualities  of  cotton  for  manu- 
facturing purposes,  and  though  the  greater  part  of  this  skill  is  acquired 
through  intimate  contact  with  actual  manufacturing  conditions,  yet  great 
aid  may  be  had  through  the  use  of  the  microscope  in  scientifically  studying 
the  structure  of  the  cotton  fiber. 

10.  Sea-island  Cotton. — This  constitutes  the  most  valuable,  perhaps, 
of  all  the  different  species.^  Its  chief  points  of  superiority  are  (a)  its 
length,  being  more  than  half  an  inch  longer  than  the  average  of  other 
cottons;    (6)  its  fineness  of  staple;    (c)  its  strength;    (d)  its  number  and 


Fig.  175. — Sea-island  Cotton. 


uniformity  of  twists,  which  allow  it  to  be  spun  to  finer  yarns;  (e)  its 
appearance,  it  being  quite  soft  and  silky.  It  is  also  characterised  by  a 
light-cream  color.  Sea-island  cotton  is  mostly  used  for  the  production 
of  fine  yarns  ranging  from  120's  to  300's;  it  is  said  that  as  fine  as  2000's  ^ 

1  Sea-island  cotton  is  the  most  valuable  of  all  varieties  of  cotton.  It  is  of  par- 
ticular importance  in  the  lace  industry  and  in  the  automobile  tire  industry.  Unfortu- 
nately, the  crop  appears  to  be  steadily  declining  in  quantity,  largely  because  of  the 
ravages  of  the  boll-weevil.  In  1917  the  United  States  crop  amounted  to  92,619  bales, 
or  35,990,000  lbs. 

^  See  Monie,  Structure  of  the  Cotton  Fiber,  p.  40,  as  authority  for  this  statement. 
A  thread  of  such  fineness  would  not  be  commercial,  and  has  never  been  prepared, 
except,  perhaps,  in  an  experimental  manner. 


SEA-ISLAND  COTTON  387 

has  been  spun  from  it.  The  "  count  "  of  cotton  yarn  means  the  number 
of  hanks  of  840  yards  each  contained  in  1  lb.  The  size  120's,  for  instance, 
means  cotton  yarn  of  such  fineness  that  120  hanks  of  840  yds.  (  =  100,800 
yds.)  weight  1  lb.  On  account  of  its  adaptability  for  mercerising  Sea- 
island  is  also  largely  employed  for  this  purpose,  in  which  case  much 
coarser  yarns  are  often  prepared  from  it. 

Some  writers  claim  that  Sea-island  cotton  is  peculiarly  of  American 
origin;  that  it  was  found  on  the  island  of  San  Salvador  by  Columbus, 
and  by  him  brought  to  Spain.  Other  writers,  among  whom  is  Masters,^ 
assert  that  this  cotton  is  of  central  African  origin.  Sea-island  was  intro- 
duced into  the  United  States  in  1786,  and  was  first  grown  on  St.  Simons 
Island  off  the  coast  of  Georgia.  It  appears  to  have  been  brought  from 
the  island  of  Angulla  in  the  Caribbean  Sea  to  the  Bahamas,  and  from 
the  latter  to  the  coast  of  Georgia.  From  St.  Simons  the  plant  extended 
to  the  Sea  Islands  of  Charleston,  where  the  finest  varieties  are  now  grown. 
Very  fine  staple  is  also  grown  along  the  coast  of  East  Florida.  Sea-island 
cotton  may  be  cultivated  in  any  region  adapted  to  the  olive  and  near  the 
sea,  the  principal  requisite  being  a  hot  and  humid  atmosphere,  but  the 
results  of  acclimatisation  indicate  that  the  humid  atmosphere  is  not 
entirely  necessary  if  irrigation  be  employed,  as  this  species  is  undoubtedly 
grown  extensively  in  Egypt.  As  a  rule,  the  quality  of  the  staple  increases 
with  the  proximity  to  the  sea;  but  there  are  exceptions  to  this  rule,  as 
that  grown  on  Jamaica  and  some  islands  is  of  rather  low  grade,  while  the 
best  fiber  is  produced  along  the  shores  of  Georgia  and  Carohna.-  Sea- 
island  requires  a  great  deal  more  moisture  than  the  upland  cottons;  in 
fact,  moisture  is  an  all-important  factor  in  the  quality  of  the  staple. 
Dry  years  give  a  poor  staple  and  wet  years  a  good  staple. 

Owing  to  the  wide  cultivation  of  Sea-island  cotton  at  the  present  time, 
for  its  growth  is  no  longer  strictly  confined  to  the  islands  of  the  sea,  it  is 
difficult  to  make  a  definite  statement  as  to  its  length  of  staple,  as  this 
will  vary  considerably  with  the  method  and  place  of  cultivation.  The 
maximum  length,  however,  may  be  taken  as  2  ins.,  and  the  minimum 
as  1|  ins.,  with  a  mean  of  If  ins.  Sea-island  cotton  gives  a  smaller  yield 
of  fiber  than  any  variety  of  cotton  grown  in  America,  but,  on  account 
of  the  greater  length  and  fineness  of  staple,  it  has  a  much  higher  market 
value.  The  average  yield  is  about  100  lbs.  of  lint  per  acre,  and  it  requires 
from  3|  to  4|  lbs.  of  seed  to  yield  1  lb.  of  hnt.  A  normal  crop  for  the 
area  in  which  it  is  grown  is  from  90,000  to  110,000  bales,  nine-tenths 
of  which  is  grown  in  Georgia  and  Florida.  In  the  limited  area  in  which 
it  is  produced  probably  500,000  bales  could  be  grown. 

Florida  Sea-island  cotton  is  very  similar  in  general  characteristics  to 

*  Jour.  Linn.  Soc,  vol.  19,  p.  213. 
2  Bulletin  A^o.  33,  U.  S.  Dept.  Agric. 


388 


COTTON 


Sea-island  proper,  possessing  about  the  same  mean  length  of  staple,  but 
being  somewhat  less  in  the  maximum  length.  Both  of  these  varieties 
of  Sea-island  show  a  maximum  diameter  of  0.000714  in.,  a  minimum  of 
0.000625  in.,  and  a  mean  of  0.000635  in. 

Fiji  Sea-island  is  less  regular  in  its  properties  than  the  two  preceding 
varieties,  and  though  its  maximum  length  is  somewhat  greater  than  Sea- 
island  itself,  yet  the  mean  length  is  about  the 
same,  as  is  also  the  diameter.     This  cotton, 
however,  has   a    very  irregular   staple  and 
contains   a    large    percentage   of  imperfect 
fibers,  which  causes  the  waste  to   be  rather 
high.     The  number  of  twists  in  the  fiber  is 
2  also  less  and  does  not  occur  as  regularly. 
Gallini    Egyptian   is    Sea-island    cotton 
grown  in  Egypt.     It  is  somewhat  inferior  to 
the  American  varieties  in  general  properties. 
It    possesses   a    yellowish  color,  which  dis- 
tinguishes it  from  the  product  of  all  other 
countries.     Gallini  cotton  has  the  bad  feature 

4  of  containing  considerable  undeveloped  and 
short  fiber,  and  this  somewhat  lessens  its 
commercial  value. 

5  The  Bahmia  variety  of  Egyptian  cotton 
is  a  form  of  Sea-island  cotton  to  which  Todaro 
has  given  the  varietal  name  of  pohjcarpum. 
It    is    characterised    by   numerous    flowers 

6  springing  from  a  single  axil,  and  an  erect, 
slightly  branching  habit,  hence  giving  a 
large  yield  per  acre.  It  was  once  thought 
that  the  Bahmia  cotton  was  a  hybrid  between  ^ 

Fig.  176— Combed  Lint  from:  (1)  okra  and  cotton,  but  in  a  Kew  Report 
Sea-island;  (2)  Egyptian  Pima;  (1887,  p.  26)  this  is  shown  to  be  incorrect. 
(3)  Meade;  (4)  Durango;  (5)  Peruvian  Sea-island  also  possesses  this 
Acala;  (6)  Lone  Star.  (Two-  game  defect,  but,  in  addition,  contains  usually 
thn-ds  Natural  Size.)  .  ,  r  r       ■  , 

quite  a  large  amount  oi  foreign  matter,  such 

as  broken  leaf,  sand,  seed  particles,  etc.  The  maximum  length  of  the  fiber 
is  If  ins.,  the  minimum  Ij  ins.,  and  the  mean  H  ins.  The  fibers  differ 
very  little  in  their  diameter,  the  average  being  0.000675  in.  Peruvian 
Sea-island  is  somewhat  coarser  in  structure  than  the  Sea- island  proper, 
being  more  hairy  in  appearance;  it  has  a  slight  golden  tint.  In  staple 
it  varies  from  If  ins.  in  length  to  If  ins.,  with  a  mean  of  I5  ins. 

Tahiti  Sea-island  resembles  the  Fiji  variety  very  closely;  it  has  a  creamy 
color.     The  length  of  staple  varies  from  1  j  to  If  ins.,  with  a  mean  of  I5  ins. 


EGYPTIAN  COTTON 


389 


It  shows  a  considerable  percentage  of  imperfect  fibers  due  to  a  short 
undergrowth  on  the  seed.     Its  average  diameter  is  0.000641  in. 

11.  Egyptian  Cotton. — The  first  variety  of  cotton  to  be  grown  in 
Egypt  was  called  Makko-Jumel;  this  went  through  many  changes  and 
evolutions,  and  gradually  changed  in  color  to  a  yellowish  brown,  the 
new  variety  being  known  as  Ashmouni,  from  the  valley  of  Ashmoun, 
where  the  change  was  first  noticed.  The  principal  varieties  of  Egyptian 
now  grown  are  the  Mitafifi,  Ashmouni,  Joanovich,  Unbari,  Sakellarides, 
Assili,  and  Hinde.  There  may  also  be  mentioned  Bahmia,  Abassi,  and 
Galhni.i 

Mitafifi,  or  Brown  Egyptian,  is  the  average  quality  of  Egyptian  cotton. 
It  is  said  to  have  been  developed  by  a  Greek  merchant  of  that  name, 


Fig.  177.— Egyptian  Cotton. 


and  it  was  first  grown  in  1883,  but  is  now  the  principal  cotton  grown  in 
Egypt.  Its  market  price  forms  the  basis  for  that  of  the  other  varieties. 
The  plant  is  characterised  by  a  bluish  green  tuft  at  the  extremity  of  the 
seed.  Its  color  is  richer  and  darker  brown  than  the  Ashmouni.  The 
fiber  is  long,  strong,  silky,  and  fine,  and  very  desirable  in  the  market. 
The  fiber  has  a  staple  of  about  If  ins.  and  is  noted  for  its  regularity  both 
with  regard  to  length  and  color.  It  was  popular  on  account  of  its  large 
yield  per  acre  (500  to  600  lbs.),  but  of  late  years  it  has  tended  to  decrease 
in  favor  of  other  varieties  of  higher  grade.  The  plant  is  said  to  withstand 
drought  and  attacks  from  insects  better  than  any  other  variety.  It  also 
requires  less  attention  in  picking  and  gives  a  better  output  in  ginning. 

^  Many  of  the  Egyptian  cottons  are  hybrids  of  G.  braziliense,  such  as  the  Ashmouni, 
Mitafifi,  Zafiri,  and  Ahassi.  It  is  probable,  however,  that  the  Ashmotmi  as  described 
by  some  writers  is  G.  microcarpum. 


390  COTTON 

Ashmouni  formerly  made  up  the  bulk  of  the  Egyptian  crop,  but  has 
now  been  largely  superseded  by  other  varieties.     It  is  produced  almost  | 
exclusively  in  upper  Egypt.     Its  color  is  a  light  brown  and  its  staple  is  ; 
over  an  inch  in  length.     It  is  the  oldest  variety  of  Egyptian  cotton  and 
differs  from  the  other  forms  in  that  its  seed  is  clean  with  no  adhering  ' 
fiber.     The  Ashmouni,  however,  is  now  ranked  as  one  of  the  poorest  } 
of  Egyptian  cottons.     Its  yield  is  relatively  small  (390  lbs.  per  acre);  | 
and  though  its  length  may  reach  1|  ins.,  the  fiber  is  weaker,  more  irregular  i 
and  dirtier  than  the  other  varieties.     It  is  chiefly  used  for  the  spinning 
of  coarse  yarns. 

Joanovich   (or    Yannovitz)  is  considered  by  some  to  be  the  best  of 
Egyptian  cottons.     It  is  named  from  the  Greek  who  produced  it,  being 
evolved  by  artificial  selection  from  Mitafifi.     The  fiber  is  strong,  clean, 
and  silky,  and  has  a  length  of  about  1\  ins.     At  the  present  time,  however,  | 
its  use  has  declined  in  favor  of  Sakellarides. 

Unhari  is  a  rather  recent  variety  evolved  from  Mitafifi,  but  it  is  not 
so  good  as  Joanovich,  being  weaker,  darker,  and  more  irregular.  Its 
color,  however,  is  lighter  than  that  of  Mitafifi.  i 

Sakellarides  was  first  planted  in  1910  and  has  steadily  grown  in  favor,  j 
The  fiber  is  soft,  silky,  and  cream-colored  with  a  fairly  reddish  tinge,  j 
The  staple  is  1.4  to  1.7  ins.  in  length.     The  fiber  possesses  many  charac- 
teristics of  Sea-island  cotton,  and  in  addition  the  yield  per  acre  is  quite  I 
high.     Its  cultivation  has  steadily  increased,  and  in  1915  over  one-half 
the  total  Egyptian  crop  was  of  this  variety. 

Assili  is  a  brown  cotton  similar  to  Mitafifi.  It  is  apparently  an  old 
variety  and  is  said  to  be  indigenous  to  the  country;  but  it  is  little  cultivated  . 
now  and  is  fast  disappearing.  The  fiber  is  strong  and  rather  regular  and  j 
there  have  been  attempts  made  during  recent  years  to  bring  back  its  j 
cultivation.  It  has  a  fine  golden-yellow  color  and  is  characterised  by  ! 
toughness  and  high  tensile  strength.  It  is,  however,  shorter  and  coarser  I 
than  Mitafifi,  the  mean  staple  being  about  Ij  ins.  in  length. 

Hinde  is  an  indigenous  cotton,  found  growing  wild  in  Abyssinia  at  the 
present  time.  It  has  a  coarse,  white,  inferior  fiber,  about  1  in.  in  length. 
It  sometimes  contaminates  fields  of  Mitafifi. 

Bahmia  was  once  cultivated  more  or  les  sextensively,  but  the  fiber  is  ) 
rather  poor,  of  a  light  brown  color  and  not  very  strong. 

Abasd  cotton  is  of  rather  recent  introduction,  being  first  produced  in 
1891,  by  a  Greek  named  Parahimona,  who  named  it  after  the  Khedive  of 
Egypt.  The  fiber  is  white  in  color  and  is  known  in  trade  as  White  Egyp- 
tian, being  the  only  white  cotton  now  grown  in  Egypt.  The  fiber  is 
longer  and  more  silky  than  Mitafifi,  though  not  so  strong.  |i 

Gallini  cotton  was  derived  from  Sea-island,  but  did   not  meet  with  ' 
much  success,  for  though  the  first  year's  crop  was  excellent,  succeeding 


AFRICAN  COTTON  391 

crops  have  shown  rapid  deterioration.  It  has  now  almost  entirely  dis- 
appeared from  cultivation. 

Sultain  is  a  very  long  and  silky  variety,  resembling  Sea-island  cotton. 
It  is  an  expensive  cotton  to  grow  and  is  limited  in  amount. 

Egyptian  cotton,  as  a  class,  is  not  so  fine  as  Sea-island,  but  is  better 
than  American  upland  cotton,  that  is,  for  goods  requiring  a  smooth  finish 
and  a  high  luster,  the  staple  being  strong  and  silky. 

The  fiber  of  Egyptian  cotton  is  especially  adapted  to  the  manufacture 
of  hosiery  yarns  and  yarns  for  mercerising.  The  United  States  imports 
Egyptian  cotton  to  the  value  of  about  $10,000,000  per  year.  The  total 
annual  crop  of  cotton  from  Egyptian  plantations  is  from  850,000  to 
875,000  bales. 

The  silky  nature  of  the  Egyptian  cottons,  and  the  fact  that  they  possess 
a  brown  color,  probably  indicate  that  they  are  really  of  Sea-island  origin, 
but  there  is  no  evidence  to  show  whence  their  deeper  coloration  than  Sea- 
island  arose,  unless  it  was  by  means  of  a  cross  with  some  highly  colored 
variety  such  as  Peruvian.  It  has  been  suggested  that  the  peculiar  soil 
conditions  of  Egypt  may  account  for  the  color,  but  there  exists  in  Egypt 
a  pure  white  variety,  ahassi,  which  shows  no  tendency  whatever  toward 
the  development  of  a  brown  coloration,  which  seems  to  preclude  this 
idea. 

Egyptian  cotton,  on  account  of  its  long,  strong,  and  silky  staple,  is 
especially  adapted  for  sewing-thread,  fine  underwear,  and  hosiery,  and 
other  goods  requiring  a  smooth  finish  and  high  luster.  It  is  interesting 
to  note  that  yarn  of  Egyptian  cotton  is  finer  than  that  of  the  same  number 
made  from  American  cotton.  The  fibers  of  the  former  are  narrower, 
which,  combined  with  their  great  flexibility,  permits  of  their  being  closely 
twisted  one  with  the  other,  thus  making  the  yarn  firmer  and  more  compact. 

12.  African  Cotton. — African  cottons  are  all  derived  from  the  herhaceum 
species.^  These  cottons  have  a  slight  brownish  tint,  and  always  contain 
a  large  amount  of  short  fibers.  The  fibers  also  varj^  much  in  diameter 
and  thickness  of  the  tube-walls,  and  many  exhibit  a  transparent  appearance 
under  the  microscope.  Yarns  made  from  these  cottons  are  always  uneven 
on  the  surface.  The  length  of  staple  varies  from  |  to  1|  ins.,  with  an 
average  of  1  in.;  the  mean  diameter  is  0.00082  in. 

Smyrna  cotton  is  grown  principally  in  Asiatic  Turkey.  It  has  a 
rather  characteristic  appearance  under  the  microscope,  being  very  even 
in  its  diameter  but  irregular  in  its  twist,  showing  many  fibers  where  the 
twist  is  almost  entirely  absent.  In  length  the  staple  varies  from  |  to  1| 
ins.,  with  a  mean  of  1  in.;   the  mean  diameter  is  about  0.00077  in. 

^  Wattes  of  the  opinion  that  G.  herbaceum  proper  does  not  occur  in  Africa,  the  chief 
cultivated  African  plants  being  derived  from  G.  obtusifolinm  and  G.  nankin,  variations 
of  the  foregoing  species. 


392 


COTTON 


13.  Indian  Cotton. —  Hingunghat  cottons  are  Indian  varieties;  the 
qiialit}'  of  these  varies  with  the  soil  and  climate  of  the  province  in  which 
the}-  are  grown.  Though  India  is  perhaps  the  oldest  of  the  cotton-produc- 
ing countries,  its  yield  if  late  years  has  been  decreasing.     The  average 


• 


Fig.  178.— African  Cotton. 

yield  per  acre  is  about  one-half  the  average  American  yield;  for  though 
the  soil  of  India  is  well  adapted  to  cotton  growing,  the  climate  is  very 
unfavorable.  Indian  cotton  has  a  very  low  yield;  in  1917  there  were 
24,781,000  acres  planted  in  cotton  and  these  furnished  only  3,228,800 


Fig.  179.— Upland  Cotton. 


bales  (500  lbs.  each)  of  fiber,  giving  an  average  yield  of  only  65  lbs.  per 
acre.  The  corresponding  statistics  for  other  cottons  for  the  year  1918  were : 
xAmerican,  37,073,000  acres  yielding  a  crop  of  12,500,000  bales,  or  170  lbs. 
per  acre;  Egyptian,  1,315,572  acres  yielding  4,930,000  bales,  or  375  lbs. 
per  acre.     As  a  rule,  Indian  cottons  are  of  rather  inferior  grade;  the  best 


AMERICAN  COTTON  393 

variety  is  the  Sural  cotton.  The  finest  sort  of  cotton  from  the  Orient 
is  known  as  "  Adenos."  Under  the  microscope  the  Hingunghat  cotton 
shows  much  variation  in  diameter,  although  it  possesses  fewer  twists  than 
the  better  grades  of  cotton,  yet,  unlike  the  African  varieties,  it  shows  very 
few  fibers  without  any  convolutions  at  all.  In  length  of  staple  it  varies 
from  I  to  1|  ins.,  with  a  mean  of  1  in,;  the  average  diameter  is  0.00084  in. 

Broach,  Tinnevelly,  Dharwar,  Oomrawuttee,  Dhollerah,  WeMern  Madras, 
Comptah,  Bengal,  and  Scinde  are  other  varieties  of  Indian  cotton,  all 
belonging  to  the  herbaceum  species.  They  have  the  same  general  properties 
and  staple  as  the  preceding,  becoming  more  and  more  inferior,  however, 
in  the  order  of  the  list  given.  For  many  years  past  the  Indian  cotton 
trade  has  been  drifting  into  a  restricted  groove.  The  produce  goes  to 
mills  which  do  not  require  a  superior  or  long  staple,  but  one  which  is 
uniform.  India  is  thus  destroyed  as  a  possible  source  of  supply  for  the 
Enghsh  mills.  The  Indian  mills  are  at  the  same  time  compelled  to  look 
to  foreign  countries  for  their  present  or  future  supplies  of  superior  staples, 
and  are  thus  more  or  less  confined  in  their  operation  to  one  class  of  goods. 

Caravonica  cotton  is  a  new  varietj'  produced  in  Australia,  though  its 
cultivation  has  also  been  introduced  into  Eg}"pt  and  Peru,  but  in  these 
latter  coimtries  the  fiber  produced  is  rather  inferior.  The  Caravonica 
cotton  from  Austraha  presents  aU  the  characteristics  of  a  good  quality- 
fiber;  it  has  a  long  staple,  from  4.5  to  5  cms.  and  is  verj'  even.  There  are 
two  principal  types,  a  silky  fiber  and  a  woolly  one.  In  microscopic 
appearance  and  in  its  microchemical  tests  Caravonica  cotton  is  very' 
similar  to  ordinary  American  cotton,  the  chief  difference  being  that 
though  the  fiber  is  quite  white  in  color,  the  points  have  a  yellowish  tinge. 

14.  American  Cotton. — Orleans  or  Gulf  cotton  is  the  typical  American 
variety,  and  is  perhaps  the  best  of  the  American  cottons.  The  fibers  are 
quite  imiform  in  length,  ha^'ing  an  average  staple  of  about  1  in.  and  a 
mean  diameter  of  0.00076  in.  It  is  almost  pure  white  in  color.  As  the 
name  indicates.  Gulf  cotton  is  grown  in  the  states  bordering  on  the  Gulf 
of  ]\Iexico  and  in  the  basin  of  the  ^Mississippi  River.  In  using  this  name, 
many  in  the  trade  seem  to  refer  to  a  cotton  liV  in.  staple,  or  something 
better  than  the  ordinan,-  ^  in.  to  1  in.  The  length  of  staple,  however,  does 
not  decide  the  grade  or  the  regional  trade  name,  for  a  considerable  quantity 
of  l^  in  to  1|  in.  cotton  is  gro^Ti  in  the  Upland  districts.  The  general 
color  of  Gulf  cotton  is  whiter  and  the  leaf  often  larger  and  blacker  than 
that  of  either  Upland  or  Texas  cotton.  The  word  "  GuK  "  is  not  much 
used  in  the  actual  bm-ing  and  selling  of  cotton,  other  trade  names  that 
have  a  more  definite  meaning  being  employed.  The  most  common  of 
these  trade  names  are  Peelers,  Benders,  Rivers,  Canebrake,  and  Red 
River,  although  a  number  of  so-called  varieties  may  be  sold  under  each 
of  these  names.     "  Peelers  "  was  formerly  a  varietal  name,  but  it  is  now 


394 


COTTON 


applied  rather  indiscriminately  to  most  of  the  If  in.  Mississippi  Delta 
cotton.  "  Benders  "  is  not  a  varietal  name.  It  is  applied  to  1|  in.  to  Iyg 
in.  cotton  of  good  body  that  is  grown  along  the  Mississippi,  Arkansas,  and 
White  rivers.  The  word  is  said  to  have  applied  originally  only  to  cotton 
that  grew  in  Mississippi,  Louisiana,  and  Arkansas  along  the  bends  of  the 
Mississippi  River.  "  Rivers  "  is  used  in  referring  to  cotton  having  a 
staple  of  liV  in.  to  1|  in.,  though  if  the  cotton  has  a  light  body  it  is  some- 
times called  "  Creeks."  "  Canebrake  "  is  the  name  applied  to  cotton 
that  is  grown  in  the  southcentral  part  of  Alabama  on  a  strip  of  black 
prairie  land.     Most  of  this  cotton  has  a  strong  Ire  in.  staple,  and  brings 


Fig.  180. — Mississippi  Delta  Cotton. 


a  higher  price  than  other  Alabama  cotton.  Texas  cotton  much  resembles 
the  foregoing,  but  has  a  slight  golden  color;  its  length  and  diameter  of 
staple  are  the  same.  "  Texas  "  is  the  trade  name  given  to  cotton  grown 
in  Texas  and  Oklahoma.  This  generally  has  about  the  same  length  of 
staple  as  Upland  cotton,  except  in  the  river  basins  and  black  prairie, 
where  the  length  is  usually  Its  in.  The  character  of  the  fiber  of  Texas 
cotton  varies  considerably  from  year  to  year.  When  the  growing  season 
is  dry,  the  fiber  is  harsher  and  shorter,  while  the  color  may  have  a  reddish 
tinge.  Many  of  the  leaves  are  dried  up  early  in  the  picking  season  by 
the  heat  and  drought.  This,  no  doubt,  accounts  for  the  trash  in  this 
cotton  being  of  a  brighter  color  and  more  broken  or  peppery  than  in  either 
the  Gulf  or  Atlantic  States  cotton.     A  large  quantity  of  boll  hulls,  shale 


PERUVIAN   AND   BRAZILIAN   COTTONS  395 

and  stalk,  is  often  found  in  this  growth  of  cotton,  and  especially  in  Okla- 
homa and  northern  Texas,  where  all  the  top  crop  does  not  mature,  owing 
to  the  shorter  growing  season.  These  half-opened  bolls  and  the  bolls 
that  do  not  open  at  all  are  usually  ginned  on  a  "  double-rib  "  huller  gin, 
and  the  cotton  is  known  in  the  trade  as  "  hollies."  Another  type  of  cotton 
where  the  open  and  mature  bolls  have  been  gathered  with  the  burr  is 
found  in  this  section  near  the  end  of  the  picking  season.  This  cotton, 
although  often  resembling  hollies,  has  a  superior  fiber,  and  may  be  graded 
in  the  usual  way.  Upland  cotton  is  another  very  similar  variety;  its 
length  of  staple,  however,  is  somewhat  less  than  the  foregoing,  averaging 
but  X6  in.  Its  twist  is  rather  inferior  to  the  Orleans,  and  it  shows  a  larger 
number  of  straight  fibers.  There  is  considerable  difference  of  opinion 
among  authors  when  discussing  the  origin  of  upland  cotton.  The  weight 
of  opinion  seems  to  be  that  the  species  is  either  G.  herbaceum  or  G.  hirsutum, 
which  many  consider  synonymous.  The  origin  of  this  species  is  much 
more  confused  than  that  of  Sea-island  cotton.  If  we  would  separate  the 
upland  cotton  into  two  species,  G.  herbaceum  and  G.  hirsutum,  probably 
the  question  would  be  simplified,  as  the  former  is  generally  considered 
of  Asiatic  origin,  while  the  other  is  attributed  to  America. 

There  are  more  than  a  hundred  recognised  horticultural  varieties  of 
upland  cotton  in  cultivation,  all  belonging  to  one  botanical  species,  G.  hir- 
sutum, native  to  the  American  tropics.     The  original  wild  plants  in  the 
tropical  zone  were  perennials,  but  the  plant  is  cultivated  as  an  annual. 
jl  The  Upland  type  of  cotton  constitutes  the  bulk  of  the  American  crop,  and 
i  is  perhaps  the  most  useful  cotton  grown.     It  is  produced  almost  throughout 
i  the  inland  districts  of  the  cotton-growing  states,  but  chiefly  in  North 
I  Carolina,   South   Carolina,   Georgia,  Alabama,  Tennessee,   and  Virginia. 
:'  Much  cotton  that  is  grown  in  the  hilly  parts  of  Mississippi,  Louisiana,  and 
I  Arkansas  is  sold  as  Upland.     This  cotton  averages  |  in.  to  1  in.  in  length, 
jl  although  a  number  of  long-staple  varieties  up  to  l^^  in.  in  length  are 
!  being  successfully  grown  in  the  Upland  districts.     In  parts  of  the  Piedmont 
section  the  length  is  very  often  more  than  1  in.,  while  in  the  sandhills 
it  may  be  less  than  |  in.     Cotton  grown  in  the  Piedmont  section  generally 
I  has  a  bright  creamy  color,  or  "  bloom,"  that  is  considered  desirable  by 
I  many  spinners.     The  leaf  is  usually  black  and  in  rather  small  pieces, 
'  while  in  the  cotton  from  the  sandy  soil  the  color  is  generally  whiter  and 
the  leaf  larger  and  brighter.     Mobile  cotton  is  the  most  inferior  of  the 
I  American  varieties;    it  varies  in  length  of  staple  from  f   to  1  in.,  with  a 
mean  of  |  in.;    its  average  diameter  is  0.00076  in.     It  shows  about  the 
same  microscopic  appearance  as  upland  cotton. 

15.  Peruvian  and  Brazilian  Cottons. — Rough  Peruvian  cotton  has  a 
light  creamy  color  and  is  rather  harsh  and  hairy  in  feel.  Peruvian  cotton 
is  often  called  kidney  cotton,  being  characterised  by  the  seeds  in  each  lobe 


396 


COTTON 


of  the  capsule  clinging  together  in  a  compact  cluster.  These  seeds  are 
black  and  without  a  persistent  fuzzy  covering.  The  lint  shows  a  wid(> 
variation  in  color  and  texture — white,  brown,  reddish,  rough  and  harsh, 
or  smooth  and  soft.  Most  of  it  has  a  shorter,  coarser,  and  more  wiry 
fiber  than  that  of  American  upland.  The  lint  of  some  varieties  is  much 
like  wool  in  appearance.  It  is  imported  chiefly  for  mixing  with  wool  or  for  , 
producing  special  effects.  i 

Kidney  cotton  is  found  in  Central  America  and  also  in  the  Philippines 
and  other  tropical  islands  of  the  Pacific,  but  it  is  not  cultivated  in  com- 
mercial quantities  outside  of  South  America.  In  length  of  staple  it 
varies  from  1|  to  Ij^  ins.,  with  a  mean  of  Ij  ins.;  its  mean  diameter  is 
about  0.00078  in.     Most  of  the  fibers  are  only  partially  twisted.     The 


wwwfegg^  **'  '-^JI^X 


Fig.  181. — American  Delta  Cotton. 


yield  of  native  Peruvian  is  very  high;  it  is  said  to  average  as  much  as  625 
lbs.  per  acre. 

Rough  Peruvian  cotton  is  mostly  grown  in  the  valleys  along  the  banks 
of  the  rivers  Chira  and  Piura.  It  is  a  tree  cotton  with  an  approximate 
age  of  six  to  seven  years.  It  grows  to  a  height  of  8  to  10  ft.  and  is  kept 
down  as  much  as  possible,  for  convenience  on  picking  the  cotton.  The 
tree  grows  two  crops  a  year,  which  is  rather  remarkable  when  we  con- 
sider that  there  is  little  or  no  rain  in  the  district;  the  moisture,  however, 
is  derived  from  the  irrigation  of  the  rivers  and  the  heavy  dews.  The 
crop  of  "  full  rough  "  cotton  is  not  a  large  one,  the  heaviest  on  record  occur- 
ring in  1913,  when  8,799,216  lbs.  were  marketed.  As  already  stated, 
there  are  two  crops  a  year,  one  being  known  as  the  San  Juan  crop  and 
the  other  as  the  Navidad  crop.  About  two-thirds  of  the  cotton  produced 
comes  from  the  section  known  as  Catacaos.  The  ginning  is  done  on  Eagle 
or  Brown  gins.     The  price  is  partly  regulated  by  the  size  of  the  bales, 


PERUVIAN   AND   BRAZILIAN   COTTONS  397 

which  vary  from  175  to  360  lbs.  in  weight.  This  is  due  to  the  fact  that 
the  transportation  is  on  the  backs  of  mules.  After  ginning  the  cottor[ 
is  sorted  for  stains;  the  first  sort  is  called  '' segunda,"  or  second;  the 
next  "  mestizo  "  or  half  breed;  the  third  "  omarillo  "  or  yellow.  There 
is  also  a  "  double  omarillo  (A A),"  the  lowest  sort  of  all.  Another  sort 
consists  of  the  very  roughest  type  of  cotton,  deeply  stained ;  this  is  called 
in  England  "  foxy  red,"  but  in  Peru  it  is  known  as  "  pardo  "  (brown), 
being  of  the  shade  of  camel's  hair.  The  production  of  this  grade,  however, 
is  very  small. 

There  is  also  the  "  moderate  rough  "  Peruvian  cotton,  which  is  chiefly 
known  to  manufacturers  in  the  United  States.  This  cotton  has  most 
of  the  characteristics  of  the  "  fully  rough  "  variety,  but  as  its  name  implies, 
does  not  have  to  the  same  degree  the  wiry  harshness  of  its  northern  cousin. 
The  sorting  of  this  quality  is  not  done  as  carefully  as  with  the  other  cotton, 
also  the  crop  is  constantly  diminishing  in  quantity,  giving  place  to  the 
better  stapled  "  Mitafifi  "  variety.  The  crop  of  the  "  moderate  rough  " 
variety  amounts  to  about  4,500,000  lbs.  a  year.  The  Catacaos  district 
raises  the  very  best  of  the  "  fully  rough  "  cotton,  and  it  is  from  this  section 
that  the  famous  FHC  and  DFC  brands  come,  these  marks  being  originally 
used  by  certain  firms  with  established  reputations.  In  the  United  States 
it  is  customary  to  grade  the  products  of  the  different  districts  by  name 
and  number,  as,  for  example,  "  No.  1  Full  Rough  Catacaos,"  "  No.  1  Full 
Rough  Sullana."  The  characteristics  of  "  full  rough  "  Peruvian  cotton 
may  be  given  as  a  staple  averaging  If  ins.,  a  "  harsh  "  feel  like  wool; 
the  diameter  of  the  fiber  is  about  twice  that  of  Texas  cotton,  while  its 
color  is  close  to  that  of  scoured  wool.  It  will  spin  easily  to  70's,  and 
the  yarn  has  a  good  breaking  strength.  Its  price  is  influenced  by  that  of 
American  cotton,  being  a  few  cents  per  pound  above  that  of  strict  good 
middling  Texas  cotton.  The  shrinkage,  or  the  amount  of  foreign  sub- 
stances, is  the  lowest  found  in  any  commercial  cotton,  owing  to  the  fact 
that  it  is  a  true  tree  cotton,  and  consequently  the  fiber  does  not  become 
contaminated  as  easily  as  is  the  case  with  shrub  cotton. 

Smooth  Peruvian  cotton  has  a  soft,  smooth  feel,  but  the  staple  is  not  so 

strong  as  the  preceding.     The  length  is  about  the  same  as  the  foregoing, 

.  as  is  also  the  diameter.     Pernamhiico  has  a  slight  golden  color  and  feels 

harsh  and  wiry.     It  is  a  variety  of  Brazilian  cotton.     It  is  rather  regular 

in  length  of  staple,  the  mean  being  Ij  ins.     The  diameter  averages  0.00079 

!  in.     Under  the  microscope  the  twists  appear  regular  and  well  defined, 

Maranhams  is  a  Brazilian  cotton  very  similar  to  the  preceding  in  micro- 
scopic appearance  and  length  and  diameter  of  staple,^  Ceara  is  also  a 
Brazilian  cotton,  rather  inferior  to  the  others  by  reason  of  its  considerable 

'  Brazilian  cotton  from  1781  to  1800  was  the  chief  source  of  the  Lancashire  cotton 
'.  supply;   but  after  that  date  American  cotton  quickly  took  its  place. 


398 


COTTON 


variation  in  length  of  staple.  Maceo  is  a  similar  variety,  but  sonaewhat 
harsher.  The  variety  known  as  G.  braziliense  is  a  representative  of  the 
so-called  "  kidney  cottons."  In  these  cottons  the  seeds  of  each  cell  are 
loosely  adherent  in  an  oval  mass,  whereas  in  the  other  varieties  of  cotton 
the  seeds  are  free  from  each  other.  G.  braziliense  is  an  arborescent  plant 
with  very  large  5  to  7  divaricate-lobed  leaves  and  very  deeply  laciniate 
involucral  bracts.  The  Brazilian  cottons  appearing  in  trade  under  the 
names  Santos,    Ceara,   Pernambuco,   etc.,   do   not   seem   to   belong  to 


Fig.  182. — Cotton  from  G.  religiosum.     (Herzog.) 


G.  braziliense,  as  they  are  not  kidney  cottons ;  they  evidently  belong  to  the 
G.  barbadense  and  G.  herbaceum  species. 

West  Indian  cottons  nearly  all  belong  to  the  peruvianum  species;  they 
are  usually  long  in  staple  and  harsh  and  wiry  in  feel,  and  only  of  moderate 
strength.  The  length  is  quite  uniform  and  averages  Ij  ins.  The  diameter 
varies  considerably,  but  has  an  average  of  about  0.00077  in.  The  twist 
is  short  and  very  uniform,  surpassing  even  Sea-island  in  this  respect. 

Owing  to  the  fact  that  the  fiber  closely  resembles  wool  in  appearance 
and  quality,  almost  the  entire  crop  of  Peruvian  cotton  is  used  in  the 
manufacture  of  merino  goods,  being  mixed  in  varying  proportions  with 


GRADING  OF  COTTON  399 

wool  fiber.  It  finds  an  extensive  use  in  the  manufacture  of  mixed  woolen 
underwear.  When  carded  its  resemblance  to  wool  is  very  close  and  its 
characteristics  are  quite  similar  to  the  animal  fiber,  having  a  rough  woolly, 
strong,  and  crinkly  staple.  So  that  when  woven  in  fabrics  along  with 
wool,  from  a  casual  examination  the  cotton  fiber  is  not  apparent.  When 
mixed  with  wool  it  reduces  the  tendency  of  the  fabric  in  which  it  is  used 
to  shrink;  it  also  gives  a  good  luster  and  finish,  besides  reducing  the  cost 
of  manufacture.  For  these  reasons  it  is  largely  used  with  wool  in  the 
manufacture  of  underwear  and  hosiery. 

16.  Chinese  Cotton. — This  includes  the  majority  of  the  Bengal  and 
Chinese  cottons  of  commerce  and  these  are  derived  mostly  from 
G.  arhoreum.  A  variety  of  Chinese  cotton  known  as  Nankin  cotton  is 
classified  as  G.  religiosum;  it  yields  a  naturally  colored  fiber,  being  rather 
dark  yellowish  brown.  It  grows  principally  in  China  and  Siam.  The 
Dacca  cotton  from  which  the  famous  muslins  were  made  is  said  to  be 
derived  from  G.  neglectum,  a  variation  of  G.  arhoremn.  This  species  is 
indigenous  to  India  where  it  was  extensively  grown  as  a  field  crop.  The 
boll  is  small  in  size  and  contains  only  a  small  number  of  seeds.  The 
fiber  is  remarkable  for  its  fineness  and  silkiness,  though  it  has  a  rather 
short  staple.  During  the  past  century,  the  cultivation  and  quality  of  this 
cotton  has  seriously  declined,  though  it  is  still  grown  in  a  very  restricted 
area. 

17.  Grading  of  Cotton. — The  principal  factors  in  the  grading  of  cotton 
are  length  of  staple,  uniformity,  strength,  color,  cleanliness,  and  flexi- 
bility. The  first  may  be  determined  by  the  gradual  reduction  of  a  tuft 
of  cotton  by  the  hand  until  individual  fibers  are  drawn  from  the  tuft,  so 
that  their  length  may  be  ascertained.  The  uniformity  of  staple  is  also 
important,  for  if  the  staple  is  uneven  the  cotton  is  of  less  value  than  if  it 
were  somewhat  shorter  but  more  even.  The  color  of  the  fiber  must  also 
be  considered,  because  this  is  of  importance  in  maintaining  an  even  shade 
of  yarn.  The  cleanliness  of  the  fiber  affects  the  amount  of  waste  made 
in  the  mill  and  hence  is  an  item  of  great  importance.  The  flexibility  of 
the  cotton  is  best  ascertained  by  the  feel;  flexibility  does  not  necessarily 
imply  lack  of  strength,  but  rather  includes  it,  for  a  weak  fiber  is  more 
liable  to  be  brittle  than  flexible.  On  the  other  hand,  a  fiber  may  also  be 
strong  and  harsh  and  yet  not  flexible,  and  hence  less  suitable  for  fine 
spinning.  The  strongest  cottons  are  used  for  warp  yarns  as  such  yarn 
is  required  to  withstand  considerable  strain  during  weaving,  a  feature 
which  is  not  required  to  such  an  extent  by  filling  yarns.  The  latter,  how- 
ever, require  a  soft  and  flexible  fiber.  According  to  Earl  and  Dean  (  U.  S. 
Bureau  of  Plant  Industry),  the  present  method  of  grading  cotton  dates 
back  to  about  1800.  Until  recently,  very  few  growers  have  had  the 
opportunity  of  acquiring  the  knowledge  of  classifying  or  grading  cotton. 


400  COTTON 

The  objects  of  grading  and  classifying  cotton  are  to  aid  (1)  in  deter- 
mining the  comparative  values  of  the  different  qualities,  and  (2)  in  describ- 
ing the  cotton  so  as  to  make  buying  and  selling  easier  when  there  are  no 
samples.  With  the  present  methods  of  buying  cotton,  especially  the  short- 
staple  varieties  (f  m.  to  liV  in.),  other  things  being  equal,  the  grade 
practically  determines  the  price  that  is  received  by  the  producer.  What 
is  known  as  staple  cotton  (1|  in.  staple  or  above)  is  usually  sold  on  sample. 
The  sample  gives  each  party  to  the  trade  a  chance  to  form  his  own  opinion, 
and  is  necessary  because  cotton  dealers  and  spinners  have  such  different 
ideas  about  the  character  and  length  of  staple. 

The  classification  of  American  mainland  cottons  is  generally  done  by 
means  of  seven  full  grades,  which  may  also  be  divided  into  half  and  quarter 
grades,  thus  giving  a  scope  of  7  full,  13  half,  or  25  quarter  grades,  as  cir- 
cumstances demand.  The  full  grades  are:  fair,  middling  fair,  good 
middling,  middling,  low  middling,  good  ordinary,  and  ordinary.  The 
half  grades  are  designated  by  the  prefix  "  strict";  and  the  quarter  grades 
by  the  prefixes  "  barely,"  meaning  the  intermediate  quality  between  the 
half  grade  and  the  next  full  grade  above,  and  ^'  fully  "  which  is  between 
the  half  grade  and  the  next  full  grade  below.  Sea-island  cottons  are 
graded  as  fellows:  extra  fine,  fine,  medium  fine,  good  medium,  medium, 
common,  and  ordinary.  Egyptian  cottons  as  a  rule,  are  quoted  under 
four  or  five  grades:  good,  fully  good,  fair,  good  fair,  and  fair.  Between 
the  grades  good  and  fully  good  fair,  there  is  often  an  intermediate  adopted, 
called  extra  fully  good  fair.  In  the  commercial  grading  of  cotton  a 
classification  is  adopted  with  reference  to  the  quality  of  the  fiber.  The 
usual  grades  are  as  follows: 

Fair  Good  middling 

Strict  middling  fair  Strict  middling 

Middling  fair  Middling 

Strict  good  middling  Strict  low  middling 

Strict  good  ordinary  Middling  tinged 

Good  ordinary  Strict  low  middling  tinged 

Strict  good  middling  tinged  Low  middling  tinged 

Good  middling  tinged  Middling  stained 

The  "  fair,"  "  middling  fair,"  "  middling,"  etc.,  are  known  as  full 
grades,  while  those  intermediate  are  half  grades.  The  "  middling " 
grade  is  the  one  universally  employed  as  a  basis  for  all  cotton  trading, 
and  the  price  of  cotton  is  fixed  on  this  standard. 

The  above  list  of  sixteen  grades  are  those  deliverable  upon  contracts 
of  the  New  York  Cotton  Exchange  (April,  1908).  Prior  to  January  1, 
1908,  nine  other  intermediate  grades,  known  as  "  quarter  grades,"  were 
recognised,  but  these  were  eliminated  on  that  date,  as  were  also  two  other 
grades,    "  low   middhng  stained "   and   "  strict  good   ordinary  tinged." 


GRADING  OF  COTTON  401 

On  April  1,  1908,  "  strict  low  middling  stained  "  was  also  excluded  from 
the  list  of  deliverable  grades  in  the  New  York  market. 

The  grade  names  that  are  in  more  or  less  general  use  throughout  the 
United  States  for  what  is  known  as  American  cotton  are  given  below: 


Above  Middling. 

1.  Fail-. 

2.  Strict  middling  fair. 

3.  Middling  fair. 

4.  Strict  good  middling. 

5.  Good  middling. 

6.  Strict  middling. 


7.  Middling.  < 


Below  Middling. 

8.  Strict  low  middling. 

9.  Low  middling. 

10.  Strict  good  ordinary. 

11.  Good  ordinary. 

12.  Strict  ordinary. 

13.  Ordinary. 


The  official  grades,  as  prepared  at  present  by  the  United  States 
Department  of  Agriculture,  include  only  nine  of  these — namely,  middling 
fair  to  good  ordinary,  inclusive.  In  an  average  season  this  range  of 
grades  covers  practically  all  the  white  cotton  grown.  The  grade  names 
containing  the  word  "  Strict  "  are  known  in  the  trade  as  half  grades, 
and  others  as  full  grades.^ 

The  grades  from  fair  to  good  ordinary  in  the  above  list  are  what  is 
known  as  white  cotton.  The  "  tinged  "  and  "  stained  "  grades  are  cotton 
showing  discoloration.  Tinged  cotton  is  cotton  that  is  only  moderately 
discolored;  that  which  is  deeply  discolored  is  known  as  stained  cotton. 
The  grade  names  given  in  the  above  list  are  used  in  nearly  all  Southern 
markets.  The  terms  "  tinged  "  and  "  stained,"  however,  are  used  in 
the  South  in  a  general  way  to  indicate  cotton  of  the  respective  grades 
which  has  become  more  or  less  discolored,  rather  than  to  indicate  a  distinct 
style  of  cotton,  as  at  New  York.  The  range  of  grades  deliverable  on 
contract  in  New  Orleans  is  about  the  same  as  that  permitted  by  the 
New  York  contract.  The  New  Orleans  contract,  however,  contains  the 
important  provision  that  no  cotton  shall  be  dehverable  which  is  of  a  lower 
market  value  than  good  ordinary  cotton  of  fair  color.  The  New  Orleans 
contract  thus  excludes  considerable  cotton  which  until  recently  has  been 
tenderable  on   contracts  at  New   York.     Moreover,   the  New   Orleans 

1  Middling,  as  the  name  shows,  is  the  middle  or  basic  grade,  and  is  the  grade  upon 
which  the  market  quotations  are  based.  All  grades  above  middling  bring  a  higher 
price,  and  all  below  middling  bring  a  lower  price,  than  that  quoted  for  middling,  the 
amount  above  or  below  varying  according  to  the  respective  differences  in  use  where 
the  cotton  is  marketed.  Many  more  grade  names  are  used  by  the  trade,  in  the  large 
spot  markets  to  describe  the  different  classes  of  colored  cottons.  The  grades  of  white 
cotton,  however,  are  the  foundation  of  all  these  other  classes.  When  the  cotton  is 
not  white,  its  nature  is  indicated  by  adding  the  words  "off  color"  or  "fair  color," 
"spotted,"  "tinged,"  or  "stained,"  as  the  case  may  be,  to  the  grade  given  to  the 
sample.  In  other  words,  there  may  be  several  classes  of  the  same  grade  of  cotton, 
namely,  middling  "off  color,"  middling  "tinged,"  or  middling  "stained." 


402 


COTTON 


classification  is  generafly  conceded  to  be  more  rigid,  grade  for  grade,  than 
that  of  New  York;  so  that  cotton  of  a  given  grade  name  in  the  New  York 
classification  might  not  necessarily  be  given  the  same  grade  in  New  Orleans. 
The  relative  values  of  different  grades  of  cotton  and  different  staples  at 
the  same  market  (New  Orleans,  April  1,  1913)  is  given  in  the  following 
table:  ^ 


Grade. 

Staple  in  Inches. 

1 

liV 

U 

1  ^- 

i  16 

u 

lA 

1i 

lA 

11 

Middling  fair 

Strict  good  middling 

Good  middling 

Strict  middling 

Middling 

Cents. 
131 
121 
12f 

121 

12A 

111 

111 

111 

Cents. 

14 

13! 

m 

121 
12  M 

123^ 

12 
111 

Cents. 

16  ?r 

16 

151 

15 

14 

13 

12^ 

12 

Cents. 

17 

16  i- 

16 

15 

14 

13 

12^ 

Cents. 

18 

17* 

17 

16 

15 

14 

13  i 

Cents. 

m 

19 
IS 
17 
16 
15 
14 

Cents. 

21 

20  .* 

19 

18 

17 

16 

1-^2 

Cents. 

22 
2U 
20 
19 

18 
16 
15 

Cents. 

22  i 

22 

20 

Strict  low  middling. . 

Low  middling 

Strict  good  ordinary. 
Good  ordinary 

19 
18 
16 
15 

In  the  trade,  the  grades  above  middling  are  usually  referred  to  as  the 
"  higher  grades,"  and  those  below  as  the  "  lower  grades." 

A/i  important  feature  of  future  business  in  cotton  is  that,  broadly 
speaking,  cotton  delivered  on  contract  consists  of  the  surplus  grades  or 
remnants  of  the  more  desirable  grades.  Even-running  cotton — that  is, 
cotton  of  substantially  one  grade — can  ordinarily  be  sold  to  spinners  at 
a  premium  above  the  price  of  a  mixed  assortment  of  grades ;  consequently 
buyers  will  not  pay  as  much  for  a  mixed  assortment  of  cotton  as  for  even- 
running  cotton.  The  spot  merchant,  therefore,  endeavors  to  class  out 
his  cotton  into  even-running  lots  and  to  dispose  of  it  in  the  spot  market 
instead  of  tendering  it  on  contract,  using  the  contract  market  to  get  rid 
of  surplus  grades  or  broken  lots,  known  in  the  trade  as  "  overs."  For 
these  reasons  a  mixed  assortment  of  grades  is  often  delivered  on  a  single 
contract. 

There  are  a  number  of  terms  employed  in  the  grading  and  selection 
of  cotton  which  it  might  be  of  interest  to  explain.  A  good  glossj',  full- 
bodied  fiber  which  has  been  well  ginned  and  packed  will  reflect  the  rays 
of  light  very  well,  and  is  for  this  reason  called  "  bloomy."     "  Blush  "  is 

1  Bull.  591,  U.  S.  Depl.  Agric. 


GRADING  OF  COTTON  403 

sometimes  emploj^ed  for  the  same  purpose.  "  Tinged,"  "  stained,"  and 
"  spotted  "  explain  themselves,  as  do  also  "  musty,"  "  sandy,"  and 
"  leafy."  "  Musty  "  cotton  is  caused  by  dampness,  and  the  unmistakable 
musty  smell  is  a  sure  indication  of  an  excess  of  moisture.  "  Sandy  " 
cotton  is  readily  detected  by  holding  a  sample  up  to  the  light  and  gently 
shaking  it,  when  the  fine  particles  will  sometimes  feel  like  a  miniature 
cloud ;  by  passing  the  palm  of  the  hand  over  the  place  where  the  samples 
have  lain  on  the  open  paper,  sand  can  always  be  detected  if  present  in 
any  quantity.  "  Bant  "  is  a  term  mostly  used  in  speaking  of  twist  cottons, 
and  denotes  strength  and  all-round  general  utility;  "  bony  "  is  sometimes 
employed  to  designate  the  same  features.  "  Soapy  "  and  "  waxy  "  are 
used  to  describe  the  sensations  experienced  when  cotton  with  these  charac- 
teristics is  passed  through  the  fingers.  "  Green  "  cotton  is  a  name  given 
to  lots  which  have  been  picked  before  the  plant  was  properly  matured; 
this  kind  of  cotton  is  seldom  met  with  except  at  the  beginning  of  the  season. 
It  is  really  unripe  and  contains  a  large  amount  of  natural  moisture.  In 
"  green  "  cotton  the  twists  have  not  developed  and  this  cotton  is  not 
suitable  for  good  spinning,  ''  Staple  "  cottons  are  those  intended  for 
twist  or  warp  yarns. 

The  chief  factors  in  the  determination  of  the  commercial  grade  of 
cotton  are: 


(1) 

Foreij 

ip.  matter  including 

(a)  Leaf. 

ib) 

Dirt  and  sand. 

(c) 

Motes. 

(d)  Neps  and  cut  fibers. 

ie) 

Stringy  cotton. 

if) 

Cut  seeds. 

(9) 

Unripe  fibers. 

(2)  Color 

Grade  and  value  do  not  run  parallel  except  for  cottons  that  have  the 
same  qualities  of  staple ;  that  is  to  say,  the  cotton  merchant  must  rate  the 
strength,  length,  pliability,  cling,  and  evenness  of  the  staple  as  well  as  the 
grade.  The  relative  spinning  value  of  cotton  must  be  considered  apart 
from  the  grade.     The  chief  foreign  impurities  in  cotton  are  as  follows:^ 

'  A  very  important  factor  in  determining  the  grade  of  a  cotton  is  its  freedom  from 
foreign  impurities,  such  as  leaf,  boll,  husk,  stalk,  seed,  and  sand.  These  impurities  are 
present  to  some  extent  in  all  cotton,  but  the  amount  depends  largely  upon  the  care 
with  which  the  cotton  has  been  gathered.  The  greater  the  amount  of  any  of  these 
impurities,  the  lower  will  be  the  grade.  The  percent  of  trash,  etc.,  does  not  run 
uniformly,  however,  in  the  same  grade  of  different  samples  of  cotton,  for  the  reason 
that  this  defect  may  be  offset  by  some  desirable  quality  in  one  sample,  or  increased 


404  COTTON 

Leaf,  Dirt,  and  Sand. — The  amount  of  leaf,  dirt,  and  sand  in  the  sample 
depends  upon  the  weather.  Usually  there  is  very  little  leaf  when  the 
cotton  is  picked  before  the  vegetation  is  killed  by  frost.  The  dirt  and 
sand  may  be  caused  by  either  wind  or  rain.  Many  of  these  impurities 
may  be  taken  out  at  the  gins  by  the  use  of  cleaners.  Fifty  pounds  or 
more  can  very  often  be  extracted  from  one  bale  of  low-grade  cotton.  If 
up-to-date  machinery  could  be  used  for  the  whole  crop,  there  would  be 
but  few  bales  grading  below  low  middling.     If,  then,  the  cotton  was  sold 

by  some  undesirable  quality  in  another  sample.     The  average  percent  of  impurities  in 
the  various  grades,  assuming  other  qualities  to  be  uniform,  is  approximately  as  follows: 

Percent. 

Strict  good  middling 11.5 

Good  middling 12 

Strict  middling 12 . 5 

Middling 13 

Strict  low  middling 13.75 

Low  middling 14 .  75 

Strict  good  ordinary 16 

Good  ordinary 17 .  50 

Ordinary 19 

The  difference  in  the  value  of  these  grades  is  usually  greater  to  the  spinner  than 
these  figures  would  indicate,  since  the  staple  of  the  lower  grades  is  very  often  weaker 
and  of  a  darker  color  than  the  higher  grades. 

To  show  where  the  impurities  are  taken  out  in  the  manufacturing  process,  the 
results  of  an  experiment  made  with  a  good  middling  cotton  are  given  as  follows: 

Percent. 

Opener  and  breaker 2 .  32 

Intermediate  lapper 1 .  69 

Finisher  lapper 1 .  44 

Picker  room  total 5 .  45 

Stripping  on  card 2 .  60 

Licker-in  on  card 0 .  50 

Flying  on  card 0 .  22 

Toppings  on  card 2 .  00 

Total  on  card 5 .  32 

Drawing  (3  processes) 0 .  33 

Slubber  frame 0.08 

Intermediate  frame 0 .  06 

Roving  frame 0 .  06 

Total  on  frames 0.53 

The  total  percentage  for  picker  and  card-room  is  11.29  percent. 


GRADING  OF  COTTON  405 

on  grade,  the  increase  in  price  would  offset  the  loss  in  weight,  and  at  the 
same  time  the  cost  for  ginning  would  be  reduced.  Much  of  the  leaf,  dirt, 
sand,  and  hulls  may  be  removed  by  the  use  of  "  huller  "  gins.  All  types 
of  gins  turn  out  cleaner  and  better  samples  if  the  cotton  is  thoroughly  dry 
when  ginned. 

Motes  are  immature  seeds  or  ends  of  seeds  that  are  pulled  off  in  the 
ginning.  Immature  seeds  are  found  more  or  less  in  all  cotton,  the  number 
depending  upon  the  variety  and  the  weather  conditions  during  its  growth 
and  maturity.  Thej^  go  out  as  waste  in  the  manufacturing  processes,  and 
their  presence  lowers  the  grade. 

Neps  and  Cut  Fibers  may  be  caused  by  feeding  the  gin  too  fast,  by  the 
gin  being  in  bad  order,  by  the  presence  of  unripe  fiber,  or  by  dampness 
in  the  cotton  when  ginned.  Neps  look  like  small  dots.  They  may  best  be 
seen  when  a  thin  layer  of  the  cotton  fibers  is  held  toward  the  light.  The 
cut  fibers  show  in  bunches  and  V-shaped  kinks,  and  give  the  sample  a 
rough  appearance.  It  is  difficult  to  judge  the  grade  or  value  of  gin-cut 
cotton;  in  order  to  be  on  the  safe  side,  the  buyer  often  penalises  such 
cotton  from  1  to  3  cents  per  pound. 

Stringy  Cotton  is  defective  cotton  produced  by  ginning  wet  or  unripe 
seed  cotton,  or  sometimes  by  a  wrong  adjustment  of  the  brushes  that  take 
the  lint  away  from  the  gin-saws.  The  fibers  in  these  strings  do  not 
separate  very  easily,  while  many  of  them  are  knocked  out  in  the  cleaning 
processes  at  the  mill,  and  go  into  the  waste. 

Cut  Seeds  are  caused  by  fast  ginning  with  a  hard  roll  and  by  broken  or 
bent  gin-saw  teeth  that  strike  the  grate-bars.  Cut  seeds  have  their  effect 
upon  the  eye  and  touch  in  grading,  and  should  be  avoided  by  the  ginner. 

Unripe  Fibers  have  a  glossy  appearance,  and  are  usually  matted 
together.  Bolls  of  cotton  that  are  picked  before  they  are  well  opened, 
and  also  the  top  bolls  that  are  forced  open  by  the  action  of  frost,  usually 
contain  unripe  fibers.  These  fibers  are  very  weak,  and  they  lower  the 
I  grade,  as  does  dirt  or  bad  fiber  of  any  kind. 

Requirements  for  Satisfactory  Ginning. — Cotton  should  be  dry  when 
ginned,  and  the  saws,  brushes,  and  other  parts  of  the  gin  should  be  in  good 
condition  if  a  smooth  sample  is  to  be  obtained.  Cleaners  used  in  connec- 
tion with  the  ginning  of  low-grade  cotton  will  improve  the  sample  from 
one  to  two  grades. 

Color. — The  weather  and  the  soil  are  the  factors  that  influence  the 
color  of  cotton.  The  early  pickings,  when  not  exposed  to  the  rain,  usually 
have  a  bright,  creamy  color,  and  if  picked  with  ordinary  care  should  grade 
good  middling  or  better.  If  left  in  the  field  too  long,  however,  the  luster 
is  lost  and  the  color  of  the  cotton  changed  to  a  "  dead  "  or  bluish  white  that 
.may  reduce  the  grade  to  good  middling  "  off  color,"  or  perhaps  middling 
or  below,  depending  upon  the  quantity  of  trash  and  dirt,     A  rain  may 


406  COTTON 

change  the  same  cotton  to  middhng  "  tinged  "  or  middling  "  stained,"  i 
according  to  the  kind  of  soil  and  the  quantity  of  rain.     Weather-tinged 
and  weather-stained  cottons  are  often  of  a  bluish  color,  and  when  not 
grown  on  sandy  land  generally  contain  mud  spots.     The  action  of  frost  i 
on  the  late  bolls  before  they  open  also  causes  spots,  tinges,  or  stains, 
depending  upon  the  amount  of  colored  cotton  that  is  mixed  with  the 
white.     This  "  frost  "  cotton  has  a  yellowish  or  buff  color,  and  is  usually 
weaker  than  other  tinged  cotton,  owing  to  the  bolls  being  forced  openj 
before  the  fiber  is  fully  developed.  | 

Cotton  picked  while  wet  with  dew  or  soon  after  rain  will  contain  ani 
excess  of  moisture.  This  may  cause  mildew,  and  thus  give  the  cotton  a  I 
bluish  cast.  A  bale  of  cotton  left  exposed  to  the  weather  in  the  gin-yard , 
very  often  has  a  mildewed  outer  surface  or  plate,  and  a  sample  drawn  i 
from  near  the  surface  of  such  a  bale  may  not  afford  a  fair  representation 
of  its  color. 

The  United  States  official  cotton  grades,  as  well  as  other  grade  stand- 
ards, require  that  cotton  grading  strict  good  middling  or  above  should 
be  of  a  bright  creamy  or  white  color,  and  free  from  any  discoloration.  A 
definite  or  fixed  color  is  not  so  absolutely  required  in  the  grades  below  strict 
good  middling.  For  example,  a  middling  may  be  creamy  or  dead  white, 
and  the  same  sample  might  grade  below  or  above  middling,  according 
as  it  contained  more  or  less  impurities.  In  the  grades  below  strict  low 
middling,  however,  the  creamy  color  or  bloom  is  lost,  since  climatic  and 
soil  conditions  that  lower  the  grade  to  this  extent  also  affect  the  color, 
giving  a  dead  white,  a  gray,  or  a  dingy  or  reddish  cast  to  the  lower  grades, 
although  they  pass  commercially  as  white  cotton. 

The  above  variations  in  color  can  best  be  seen  when  the  cotton  is 
placed  in  a  north  light.  If  out  of  doors,  the  examiner's  back  should  be 
turned  toward  the  sun,  so  that  his  line  of  vision  will  be  more  or  less  parallel 
to  the  rays  of  light.  The  best  light  for  grading  may  be  had  on  a  clear  day 
between  the  hours  of  9  a.m.  and  3  p.m.  It  is  sometimes  hard  to  judge 
the  color  of  cotton  on  a  day  that  is  cloudy  or  partly  cloudy,  because  of 
reflected  light.  This  difficulty  is  frequently  experienced  along  a  coast 
where  there  are  numerous  clouds.  The  reflection  may  be  more  trouble- 
some when  grading  near  large  bodies  of  water. 

Sample  for  Grading. — In  sampling  a  bale  of  cotton  for  grading,  about 
3  ozs.  should  be  drawn  from  each  side  of  the  bale  from  a  sufficient  depth 
to  be  fairly  representative.  Wlien  the  samples  are  drawn  from  a  bale 
of  compressed  cotton  they  should  be  allowed  to  lie  for  a  day  before  grading, 
so  that  the  matted  condition  and  deadened  color  may  disappear.  This 
should  be  done  for  the  reason  that  many  bales  have  a  thin  plate  on  one 
side  that  is  of  a  higher  or  lower  grade  than  the  rest,  usually  caused  by  a 


STATISTICAL 


407 


"  roll  "  left  in  the  "  breast  "  of  the  gin  from  cotton  of  a  different  lot 
previouslj^  ginned. 

Tests  have  been  made  to  show  the  relative  values  of  the  different 
grades  of  cotton  in  terms  of  the  strengths  of  the  spun  yarns.  The  results 
were  as  follows: 


Good 
Middling. 

Middling. 

Low 
Middling. 

Good 
Ordinary. 

Average  breaking  strength,  lbs .  .  . 
Average  weight  60  yards,  grains . . 

Average  number 

Strength  per  grain 

68.4 
36.03 

13.88 
1.89 

71.81 

38.2 
13.08 

1.88 

65.4 
36.9 
13.55 
1.77 

63.1 
36.0 
13.89 
1.75 

The  U.  S.  Department  of  Agriculture  has  made  a  study  of  the  waste 
produced  and  the  character  of  the  yarn  made  from  different  grades  of 
cotton. 

The  following  table  gives  the  percentage  of  waste  (visible  and  invisible) 
resulting  from  the  manufacture  into  22 's  warp  yarn  of  the  five  grades  of 
1-in.  upland  cotton  studied,  also  the  breaking  strength  (in  pounds  per 
skein)  of  both  the  unbleached  and  bleached  yarn  produced  from  each 
grade : 


Waste, 
Percent. 

Breaking  Strength. 

Grade. 

Unbleached 
Yarn. 

Bleached 
Yarn. 

Middling  fair 

Good  middling 

7.43 

8.49 

10.38 

12.39 

16.47 

69.5 
63.2 
60.5 
61.4 
56.4 

66.7 
61  5 

Middling 

Low  middling 

58.3 
63  4 

Good  ordinarv 

60  9 

A  good  knowledge  of  the  amount  of  waste  given  b}^  different  qualities 
of  cotton  is  an  important  point  for  the  consideration  of  the  spinner  in 
the  valuation  of  a  sample  of  cotton. 

18.  Statistical. — The  following  tables,  indicating  the  extent  of  the 
cotton  manufacturing  industry  in  the  United  States  for  the  year  1919, 
have  been  taken  from  the  U.  S.  Census  Reports: 


408  COTTON 

ANALYSIS  OF  COTTON  PRODUCTION  BY  QUANTITY  AND  VALUE 


Article. 


Woven  goods  over  12  ins.  width. 

Unbleached  and  bleached  sheet- 
ings, shirtings  and  mushns .... 

Ducks 

Ginghams 

Drills 

Twills  and  sateens 

Ticks,  denims 

Cotton  flannel 

Velvets,  velveteens,  corduroys 
and  plushes 

Toweling  and  Terry  weaves 

Tapestries 

Pillow  tubing 

Mosquito  netting  and  tarlatan  . .  . 

Bags  and  bagging 

Other  woven  goods  over  12  ins.  in 
width 

Lace  and  lace  curtains 

Tape  and  webbing 

Twine 

Cordage  and  rope 

Thread 

Yarns  for  sale 

Cotton  waste  for  sale 


Value  per 

Total  Square  Yards. 

Total  Value. 

Square 
Yard, 

Cents. 

1914. 

1919. 

1914. 

1913. 

1914. 

1919. 

6,813,540,681 

6,317,397.984 

489,985,277 

1,489,610,779 

7.2 

23.8 

3,852,471,903 

3,194,100,981 

196,520,984 

477,407,901 

5.1 

15.0 

251,367,711 

336,500,457 

49,179,212 

327,082,551 

19.5  |70.0 

489,661,133 

368,.3G7,601 

36,706,542 

85,070,745 

7.5 

23.1 

289,969,885 

314,822,109 

21,256,698 

73,253,640 

7.4 

23.0 

392,108,735 

424,478,033 

32,891,854 

101,056,691 

8.4 

23.8 

229,330,389 

220,381,180 

24,947,983 

70,080,557 

10.9 

31.8 

263,862,227 

268,067,853 

24,352,020 

60,152,426 

9.2 

22.2 

29,128,703 

40,183,780 

8,540,143 

36,673,551 

29.3 

91.3 

75,798,907 

75,165,515 

9,805,232 

31,230,370 

12.9 

41.6 

■     10,137,710 

21,705,586 

5,411,592 

17,295,608 

53.2 

79.6 

15,212,622 

12,112,573 

1,483,847 

2,555,543 

9.7 

21.0 

99,981,783 

34,425,307 

2,820,524 

3,273,376 

2.86 

9.4r 

129,357,002 

82,433,300 

9,705,616 

13,139,820 

7.5 

16.3 

687,151,971 

924,713,709 

66,363,030 
12,521,053 

281,338,000 

28,258,489 

Lineal  Yards. 

Lineal  Yards. 

1,026,231,549 

1,065,551,328 

Pounds. 

Pounds. 

13,284,875 

11,860,195 

2,792,125 

5,935,245 

5,515,658 

6,815,848 

891,223 

2,857,275 

26,507,023 

26,441,943 

22,917,099 

55,009.176 

497,986,999 

618,201,812 

127,363,952 

453,764,883 

317,360,019 

315,314,228 

14,421,929 

36,357,674 

COTTON  USED  IN  COTTON  MANUFACTURING 


Kind. 


Total 

Cotton  (raw): 

Domestic 

Sea-Island 

American  Egyptian 

Other  long  staple  (1|  ins.  and  over) 

Short  staple  (under  1|  ins.) 

Foreign 

Egyptian 

Other 


1919. 


5,529,422 


5,329,973 

52,154 

40,726 

9G1.450 

4,275,643 

199,449 

128,959 

70,490 


2,731,404,436 


2,612,851,431 

20,804,901 

20,695,568 

485,010,838 

2,086,340,124 

118,553,005 

88,710,604 

29,842,401 


STATISTICAL 


409 


The  cotton  industry  of  the  United  States  shows  considerable  shifting 
toward  the  base  of  supply;  in  1880  there  were  in  the  cotton-producing 
states  of  the  South  only  561,000  spindles,  whereas  in  1922  this  had  grown 
to  15,000,000  spindles,  or  43.21  percent  of  all  the  cotton  spindles  in  the 
United  States. 

DISTRIBUTION  OF  WORLD'S  COTTON  SPINDLES— FOR  YEAR   1920 


Country. 


Number 

of 
Spindles. 


Spindles 

at 
Work. 


Bales  of 
Cotton 
Used. 


Great  Britain 

France 

Germany , 

Italy 

Czechoslovakia 

Spain 

Belgium 

Switzerland 

Poland 

Sweden 

Holland 

Portugal 

Finland 

Denmark 

Norway 

India 

Japan 

China 

United  States  of  America 

Canada 

Mexico 

Brazil 

Simdries 

Total 


58,692,410 

9,400,000 

9,400,000 

4,514,800 

3,584,420 

1,800,000 

1,572,500 

1,536,074 

1,400,000 

670,350 

.    597,492 

482,000 

239,828 

116,644 

72,724 

6,689,680 

3,690,090 

1,600,000 

35,872,000 

1,200,000 

720,000 

1,600,000 

250,000 


50,045,902 

5,658,630 

5,230,996 

3,932,893 

1,603,857 

1,800,000 

1,467,452 

1,380,546 

126,846 

403,399 

593,942 

482,000 

239,828 

92,404 

62,340 

5,318,603 

3,155,271 

1,280,036 

35,499,000 

681,012 

253,424 

303,068 

46,140 


145,701,462 


119,657,589 


3,185,314 

629,799 

484,911 

670,702 

97,877 

390,000 

234,906 

79,514 

8,184 

70,667 

107,975 

67,491 

26,257 

23,516 

10,269 

1,695,365 

2,083.433 

690,398 

6,425,344 

118,446 

44,321 

75,552 

16,700 


17,236,941 


THE  WORLD'S  COTTON  SPINNING  SPINDLES 


Locality. 

1919 
(in  Millions). 

1922 

(in  Millions). 

Europe 

Asia 

96.37 
8.88 

31.33 
0.25 

99.46 
13 .  42 

America 

Sundries 

40.19 
0.25 

Totals .  .  . 

136.83 

153.32 

410 


COTTON 


The  following  diagram  furnishes  some  interesting  statistics  concerning 
the  commercial  facts  relative  to  cotton: 


LI  I  M 


50 


45 


40 


1    1   1   1    1   1   1   1   M 

-  -  Pounds  per  Acre  Los't- 

-  -  Due  to  Insect  Pests| — 

1 

1 

1 

w 

11 

1 

ULE 

jljtl 

M 

1l 

: 

1 

H 

HHi 

1 

Fifty  Years  in  Cotton 


1870         1875         1880        1885        1890         1895        1900         1905         1910         1915        1920'22 
Fig.  183. — 'Analytical  Study  of  Cotton  Production,  Wages,  Prices  and  Exports  over 
Fifty  Years.     {Magazine  of  Wall  Street.) 


The  following  are  interesting  statistics  of  the  cotton  industry  (1909) 

Pounds. 

World  production  of  cotton 8,505,191,000 

United  States  produced 5,157,691,000 

British  India  produced 1,801,000,000 

Egypt  produced 455,520,000 

Russia  produced 360,000,000 

China  produced 300,000,000 

Brazil  produced 180,000,000 

Turkey  produced 16,000,000 

Value  of  crop  in  United  States $700,000,000 

Capital  engaged  in  manufacturing $821,109,000 

Value  of  products $629,699,000 

Number  of  establishments 1,322 

Persons  employed 387,252 


CHAPTER  XIV 
THE   PHYSICAL    STRUCTURE   AND    PROPERTIES    OF    COTTON 

1.  Physical  Structure. — Physically  the  individual  cotton  fiber  consists 
of  a  single  long  tubular  cell,  with  one  end  attached  directly  to  the  surface 
of  the  seed.  Its  length  is  about  1200  to  1500  times  its  breadth.  The  outer 
end  of  the  fiber  is  pointed  and  closed;  the  end  originally  attached  to  the 
seed  is  generally  broken  off  irregularly.  While  growing  the  fiber  is  round 
and  cylindrical,  having  a  central  canal  running  through  it;  but,  after 
the  enclosing  pod  has  burst,  the  cells  collapse  and  form  a  flat  ribbonlike 
fiber,  which  shows  somewhat  thickened  edges  under  the  microscope.  The 
juices  in  the  inner  tube,  on  the  ripening  of  the  fiber,  are  drawn  back  into 
the  plant,  or  dry  up  on  exposure  to  light  and  air,  and  in  so  doing  cause  the 
fiber  to  become  twisted  into  the  form  of  an  irregular  spiral  or  screwlike 
band,  by  reason  of  the  unequal  collapse  and  contraction  of  the  cell-wall. 

A  study  of  the  growth  of  the  cotton  fiber  has  been  made  by  W.  L.  Balls 
{Proc.  Roy.  Soc,  1919,  p.  542);  he  adopted  the  method  of  hydration  of 
cellulose  according  to  Cross  and  Bevan's  partial  xanthation  process, 
and  obtained  a  swelling  of  the  fibers  which  on  microscopic  examination 
exhibits  well-defined  zones  corresponding  to  rings  of  growth  during  the 
day  and  night,  the  latter  being  the  active  period.  It  was  found  that  up  to 
the  twenty-sixth  day  there  is  very  little  evidence  of  structure,  but  from 
then  on  to  the  fiftieth  day  the  development  of  well-defined  growth  rings 
may  be  detected,  together  with  the  formation  of  pits  in  the  cell-wall  and 
a  tendency  to  produce  the  well-known  twist  in  the  fiber. 

The  number  of  twists  in  the  cotton  fiber  in  the  raw  state  is  said  to  be 
from  150  to  400  per  inch.  Bowman  gives  the  following  table  as  an  approx- 
imate estimate  of  the  mean  number  of  twists  per  inch  in  various  classes  of 
cotton : 

Sea-Lsland 300 

Egyptian 228 

Brazilian 210 

American  peeler 192 

Indian  (Surat) 150 

2.  Unripe  or  Dead  Fibers. — Fibers  that  have  not  ripened  differ  some- 
what in  these  characteristics,  being  straight  and  having  the  inner  canal 

411 

I 


412     THE   PHYSICAL   STRUCTURE   AND    PROPERTIES   OF   COTTON 

more  or  less  filled,  in  consequence  of  which  they  do  not  spin  well  and  are 
difficult  to  dye,  showing  up  as  white  speclvs  in  the  finished  goods;  this  is 
known  as  dead  cotton.  The  presence  of  "  dead  "  or  unripe  cotton  is 
very  objectionable,  as  the  fiber  is  weak  and  brittle,  and  consequently 
reduces  the  strength  and  durability  of  the  yarn  into  which  it  may  go. 
There  is  a  considerable  amount  of  unripe  or  partly  ripened  bolls  always 
to  be  found  in  cotton  fields,  and  the  fibers  from  these  consist  almost 
exclusively  of  "  dead  cotton  "  (Fig.  185).  The  proper  utihsation  of  such 
cotton  is  a  serious  question,  for  the  fiber  is  too  weak  to  be  used  for  spinning, 
and  the  cost  of  gathering  and  giiming  makes  the  fiber  too  expensive  for 
most  other  purposes,  such  as  for  absorbent  cotton,  cotton  batting,  or 
material  for  guncotton. 


Fig.  184. — Sea-island  Cotton  under  Polarised  Light.     (X360.)     (Herzog.) 


According  to  H.  Kuhn,  a  greater  proportion  of  dead  fibers  occurs  in 
the  coarser  varieties  of  cotton  than  in  the  finer,  and  this  is  accounted 
for  by  the  fact  that  such  fibers  draw  up  more  juice  from  the  seed,  which 
thus  becomes  impoverished  before  the  maturity  of  all  the  adhering  fibers. 
Dead  cotton  is  far  more  common  in  Indian  cottons  than  in  Sea-island  or 
Egyptian.  Haller  states,  that  unripe  cotton  fibers  differ  from  the  matured 
fibers  in  their  chemical  behavior.  A  potassium  iodide  solution  of  iodine 
gives  a  dark  yellowish  brown  color  with  the  ripe  fibers  while  the  dead 
fibers  remain  a  light  yellow.  On  treatment  with  a  zinc  chloride  solution  of 
iodine  dead  cotton  gives  a  blue  coloration  more  rapidly  than  the  normal 
fiber.  The  dead  fibers  also  show  a  different  reactivity  toward  many 
dyestuffs. 

Haller  1  gives  the  following  description  of  the  properties  of  unripe 
cotton.  Under  the  microscope  the  lumen  is  seen  to  contain  a  considerable 
quantity  of  matter,  and  the  fibers  do  not  appear  so  twisted  as  the  ripe 

1  Chem.  Zeif.,  1908,  p.  838. 


INNER  CANAL  OR  LUMEN  OP  FIBER 


413 


fibers.  When  treated  with  an  ammoniacal  solution  of  copper  oxide,  the 
fibers  of  dead  cotton  swell  up  but  do  not  dissolve.  When  a  mixture  of  ripe 
and  unripe  fibers  is  treated  with  a  solution  of  chlor-iodide  of  zinc,  the 
unripe  fibers  very  quickly  develop  a  blue  color,  which  appears  much  more 
slowly  with  the  ripe  fibers.  A  solution  of  iodine  in  potassium  iodide 
colors  the  ripe  fibers  a  dark  yellowish  brown,  whereas  the  unripe  fibers 
acquire  only  a  light  yellow  color.  When  treated  with  an  18  percent 
solution  of  caustic  soda,  the  unripe  fiber  retains  what  twist  it  has,  and 
only  becomes  lighter 
and  more  transparent. 
The  ripe  and  unripe 
fibers  also  exhibit 
marked  differences 
toward  polarised  light. 
If  a  mixture  of  the 
two  classes  of  fibers  is 
boiled  in  caustic  soda 
solution  (2°  Be.),  and 
then  soured,  washed, 
and  dyed  with  indigo, 
the  ripe  fibers  take  up 
the  dye-stuff  readily, 
but  the  unripe  fibers 
are  dyed  to  only  a 
very  limited  extent. 
The  reverse,  however, 
is  the  case  when  dyemg 
with  the  substantive 
dyes,  the  unripe  fibers 

acquiring  a  deeper  color.     When  dyed  with  basic  colors  on  a  tannin-anti- 
mony mordant,  the  unripe  fiber  is  only  dyed  on  the  exterior.^ 

3.  Inner  Canal  or  Lumen  of  Fiber. — The  presence  of  an  inner  canal 
in  the  cotton  fiber  no  doubt  adds  to  its  absorptive  power  for  liquids,  and 

^  Clegg  and  Harland  {Jour.  Text.  Inst.,  1923,  p.  125)  have  published  the  results  of 
an  investigation  on  the  influence  of  "neps"  consisting  of  dead  cotton  hairs  on  the 
dyeing  of  fabrics.  It  is  stated  here  that  a  distinction  must  be  made  between  "unripe" 
fibers  and  "dead"  fibers.  It  is  the  latter  that  are  to  be  observed  in  the  form  of  little 
balls  or  tangled  clumps  occurring  more  or  less  on  the  surface  of  the  cloth  and  these 
little  masses  of  fiber  resist  the  action  of  the  dye,  or  at  least  show  up  as  much  lighter 
in  color  than  the  surrounding  normal  fibers.  The  undyed  effect  is  said  to  be  due 
really  to  the  fact  that  the  dead  fibers  are  so  thin  in  section  that  although  really  dyed 
like  the  rest  of  the  cotton,  they  appear  almost  undyed  by  contrast  in  the  same  manner 
that  a  thin  plate  cut  from  a  thick  piece  of  colored  glass  will  appear  almost  colorless. 
In  other  words,  the  undyed  appearance  is  an  optical  effect  and  is  not  due  to  the  fiber 
resisting  the  action  of  the  dye. 


Fig.  185. — Unripe  or  Dead  Cotton  Fibers.     (Herzog.) 


414      THE  PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  COTTON 


its  capillary  action  allows  cotton  to  retain  salts,  dyestuffs,  etc.,  with  con- 
siderable power;  but  too  much  importance  in  this  respect  must  not  be 
attributed  to  the  canal,  for  when  cotton  is  mercerised  the  canal  is  almost 

entirely  obliterated  by  the  walls 
being  squeezed  together  (Fig.  186), 
and  yet  mercerised  cotton  is  much 
more  absorptive  of  dyes,  etc.,  than 
ordinary  cotton.  The  capillarity  of 
the  cotton  fiber  is  no  doubt  princi- 
/~\         V!J  ^-^XJ  I  %  ^        pally  due  to  the  existence  of  minute 

n  p  \>^       \__-^        pores  which  run   from   the  surface 

inward.  The  crystallisation  of  salts 
in  these  pores  and  in  the  central 
canal  may  lead  to  the  rupturing  of 
the  fiber,  as,  for  instance,  when  filter- 
paper  is  made  by  disintegrating  cotton  fibers  by  saturating  with  water 
and  then  freezing. 

4.  Dimensions  of  Cotton  Fibers. — The  following  table  of  the  length 
and  diameter  of  different  varieties  of  cotton  fibers  has  been  collated  as  a 
mean  of  several  observers: 


Fig.  186. — Cross-sections  of  Mercerised 
Cotton  Fibers  Showing  the  Appearance 
of  the  Inner  Canal. 


Name  of  Cotton. 

Length, 
Mm. 

Diameter, 
Microns. 

Name  of  Cotton. 

Length, 
Mm. 

Diameter, 
Microns. 

Sea-Island 

41.9 
46.6 
39.0 
39.3 
45.7 
48.7 
42.9 
38.9 
32.1 
37.2 
34.4 
31.8 
28.5 

28.8 
35.2 
30.2 
29.7 
28.1 
29.3 
29.9 
30.0 
37.5 

9.65 

16.18 

16.7 

16.3 

15.3 

16.7 

17.1 

18.7 

19.5 

22.8 

18.8 

20.4 

20.0 

20.0 

21,5 
21.5 

West  Indian 

American 

Orleans 

Upland 

32.3 

27.0 
29.5 
24.3 
25.0 
25.4 
24.2 
25.0 
25.1 
27.6 

28.3 
28.2 
20.9 
23.0 
23.6 
24.1 
23.8 
21.8 
20.4 
25.7 
21.4 

19  6 

Edisto 

Wodomalam 

John  Isle 

20.9 
19.2 
19  4 

Florida 

Texas 

Mobile 

Georgia 

Mississippi 

Louisiana 

Tennessee 

African 

16  6 

Fitschi 

19  4 

Tahiti 

10.3 

Peruvian 

13.4 

Egyptian 

Gallini 

15  0 

Brown 

20.8 

White 

Indian 

19.3 

Smyrna 

Hingunghat 

Dhollerah 

Broach 

20.0 

Brazilian 

21  5 

Maranham 

21.8 

Pernambuco 

Surinam 

Tinnevelly 

Dharwar 

21.0 
21  0 

Paraiba 

Oomrawuttee 

Comptah 

21  5 

Ceara 

21  5 

Maceo 

Madras 

21.8 

Peruvian  rough 

Smooth 

Scinde 

Bengal 

Chinese 

21.3 

23.7 

Agerian 

24  1 

DIMENSIONS   OF  COTTON   FIBER 


415 


The  cotton  fiber  is  rather  even  in  its  diameter  for  the  greater  part  of 
its  length,  though  it  gradually  tapers  to  a  point  at  its  outgrowing  end. 
The  point  of  the  fibers  may  occur  in  a  variety  of  forms:  cone-shaped, 
spatula-shaped,  rounded  off,  club-shaped,  etc.  Generally  it  is  very  thick 
walled.  Many  varieties  of  cotton  exhibit  a  marked  "  tail  "  toward  the 
apex,  particularly  the  finer  and  longer  staples.  These  tails  have  no 
convolutions,  and  practically  no  central  canal  or  lumen,  the  space  being 
almost  filled  by  the  secondary  thickening.  The  apex  itself  may  exhibit 
various  shapes,  acutely  conical,  blunt  ended,  spatulate,  or  club-shaped,^ 
though  little  is  known  as  to  its  exact  structure.  These  tails  are  said  by 
some  manufacturers  to  break  off  in  the  various  processes  preparatory  to 
spinning,  but  confirmation  of  this  opinion  is  required.  The  different 
varieties  of  cotton  show  considerable  variation,  both  in  length  and  diameter 
of  fiber;  in  Sea-island  cotton  the  length  is  nearly  2  ins.,  while  in  Indian 
varieties  it  is  often  less  than  1  in.  The  diameter  varies  from  0.00046  to 
0.001  in.;   the  longest  fibers  having  the  least  diameter. 

Bulletin  No.  33  (U.  S.  Dept.  Agric.)  gives  the  following  table  compiled 
from  numerous  measurements  taken  during  a  period  of  years,  showing 
the  maximum,  minimum,  and  average  length  of  fiber  for  some  of  the 
most  important  varieties  of  cotton,  as  well  as  the  average  diameter  of  the 
same: 


Variety. 

Length  in  Inches. 

Diameter, 

Inches. 

Maximum. 

Minimum. 

Average. 

Sea-island 

1.80 
1.16 
1.12 
1.06 

1.41 

0.88 
0.87 
0.81 

1.61 
1.02 
1.00 
0.93 

0  000640 

New  Orleans 

0  000775 

Texas                       

0  000763 

Upland 

0.000763 

Egyptian 

1,52 

1.30 

1.41 

0.000655 

Brazilian 

1.31 

1.03 

1.17 

0.000790 

Indian  varieties: 

1 

Native 

1.02 

0.77 

0.89 

0.000844 

American  seed .     

1.21 
1.65 

0.95 
1.36 

1.08 
1.50 

0  000825 

Sea-island  seed 

0.000730 

From  these  measurements  it  will  be  observed  that,  as  a  rule,  the 
longer  the  fiber  the  less  is  its  diameter.  The  extreme  variations  in  the 
above  measurements  of  length  is  from  0.25  to  0.30  in.  In  proportion 
to  the  size  of  the  fiber,  the  variation  in  diameter  is  much  greater  than 
that  for  the  length. 


'  Hohnel,  Die  MiJcroskopie  dcr  Technisch  Verwendeten  Faserstofe,  1905,  p.  30. 


416     THE  PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  COTTON 

Deschamps  ^  classifies  commercial  cottons  into :  (a)  fine  cotton  with 
fibers  up  to  20  microns  diameter;  (6)  ordinary  cotton  with  fibers  from 
20  microns  to  23  microns;  (c)  coarse  cotton  with  fibers  of  23  microns 
and  over. 

5.  Measurement  of  Cotton  Staple. — There  are  two  general  characteris- 
tics of  cotton  samples  considered  in  the  selection  by  the  spinner,  the  grade, 
and  the  staple.  The  factors  that  principally  influence  the  grader  are,  first: 
leaf,  dirt,  sand,  or  other  foreign  substance;  second,  color;  and  third,  the 
handling  or  ginning.  Staple  refers  primarily  to  the  length  of  the  fibers, 
and  indicates  that  characteristic  of  a  percentage  of  the  fibers  contained 
in  a  given  bulk.  Staple  cotton  is  generally  referred  to  by  the  trade  as 
cotton  that  is  li^^  ins.  or  better  in  length.  Length,  strength,  luster, 
"  cling,"  and  other  spinning  qualities  are  recognised  only  in  a  general 
way  in  grade  standards,  but  are  especially  characterised  in  stapling. 
The  staple  of  cotton  is  in  fact  an  expression  of  its  suitability  for  certain 
purposes,  judged  from  a  generally  recognised  appreciation  of  varying 
factors.  The  perspicacity  of  the  judge  is  a  factor  of  the  most  varying 
functions,  and  this  is  again  subjected  to  fluctuations  of  temperament  and 
practical  experience  of  the  working  values  of  the  characteristics  of  the 
fibers  he  may  be  selecting.  This  introduces  a  personal  element  difficult 
to  estimate,  and  it  is  not  often  that  the  buyer  can  or  does  test  his  own 
personal  knowledge  by  actual  results  in  the  spinning  practice.  The 
cotton  spinner's  estimate  of  cotton  value  is  based  on  average  of  the  varying 
factors,  chiefly  upon  hair  length.  This  factor  is  emphasised,  perhaps,  for 
two  reasons:  the  length  of  the  fiber  is  to  some  extent  indicative  of  other 
characteristics,  and  it  is  the  easiest  recognised.  On  this  particular  point 
one  will  find  the  nearest  approach  to  agreement  in  the  judgment  of  experts. 

There  is  one  general  method  of  estimating  the  length  of  the  fibers, 
that  is,  to  select  a  bunch  of  fibers,  straighten  out  or  parallelise  the  individual 
hairs  between  the  finger  and  thumb  and  ascertain  the  length  of  the  tuft  so 
formed.  This  method  takes  cognisance  only  of  a  certain  percentage  of  the 
hairs  contained  in  the  selected  bunch  and  does  not  indicate  the  relative 
percentage  of  short  hairs  contained  in  the  body  of  the  tuft  or  those  fibers 
removed  during  the  operation  of  smoothing  out  the  fibers.  Some  general 
idea  of  the  uniformity  of  the  fibers  may  be  obtained  by  pulling  a  fairly 
large  tuft  of  cotton  apart  by  both  hands;  the  appearance  of  the  edges  of 
both  tufts  indicates  the  regularity  of  length  of  fiber,  but  it  is  vague.  A 
"  hard  "  edge,  that  is,  one  in  which  the  ends  of  cotton  appear  to  be  all 
the  same  length,  is  supposed  to  indicate  a  regular  staple.  This  method 
may  be  apphed  with  varying  degrees  of  accuracy;  the  master  carder 
will  test  the  staple  from  a  few  hairs  drawn  from  the  already  straightened 
"  preparation  "  and  placed  on  his  sleeve,  while  the  expert  cotton  buyer 

'  Le  Colon,  p.  165. 


MEASUREMENT  OF  COTTON  STAPLE 


417 


will  carefully  prepare  the  tuft  by  a  dozen  or  more  drawings  from  the  tuft 
and  place  each  separately  on  a  block  covered  with  black  velvet  or  plush 
with  more  exact  measurements  and  observation  of  other  characteristics. 
In  the  former  case,  most  of  the  natural  short  hairs  may  have  been  removed 
in  process,  while  some  long  ones  may  have  been  broken  in  the  cleaning  and 
carding.  In  the  latter,  as  many  as  possible  of  the  shorter  hairs  will  be 
retained  and  will  be  exhibited  for  estimation.  An  astute  buyer  will  by 
this  method  estimate  within  a  very  small  margin  the  amount  of  waste 
that  should  occur  in  the  spinning  process,  always  assuming  that  the 
machinery  is  technically  correct. 

The  former  method  may  be  considered  a  commercial  or  technical  one; 
a  scientific  procedm'e  is  one  introduced  by  Dr.  N.  A.  Cobb,  a  cotton  expert, 
formerly  chief  of  the  Department  of  Agriculture  at  Washington,  D.  C.  In 
this  system,  fibers  are  taken  from  the  mass  of  ginned  cotton  (or  from  the 
seed)  and  distributed  thinly  between  two  glass  slides;  the  image  of  the 
fibers  is  projected  on  to  a  screen,  by  means  of  a  lens  and  a  strong  Ught. 
The  fibers  are  exliibited  highly  magnified  and  in  a  natural  condition,  and 
several  characteristics  are  rendered  visible:  the  cm'l  of  the  hair,  the 
convolutions,  etc.  The  length  of  the  hair  is  measured  by  a  map  measurer 
run  along  each  fiber.  Dr.  Cobb  does  not  claim  for  this  any  commercial 
utility,  but  it  is  obviously  a  valuable  method  in  research  work.  Its 
limitations  are  the  small  number  of  hairs  that  can  be  operated  on  at  one 
time,  and  the  tedious  use  of  the  map  measurer. 

It  has  been  mentioned  that  in  preparing  the  cotton  tuft  for  the  com- 
mercial estimate  of  length,  manj^  short  fibers  are  discarded,  probabh^  not 
the  extremes  of,  say,  I  in.,  but  mostly  those  of  a  length  more  nearly 
approaching  the  average  staple.  Even  if  the  former  were  all  removed 
they  would  affect  the  relative  percentages  very  little.  To  illustrate  this 
effect  a  collection  of  fibers  extracted  from  a  bale  of  Ij^  in,  American 
cotton  and  measured  by  Dr.  Cobb's  method  shows: 


Fibers  of    J  in.  to    f  ia. 


(  (                  1          H             5     '  < 
2                           8 

it                  3          1 

4 

(              7     <  ( 
8 

1 

'    U  " 

"      U    ' 

'  If " 

"     n  ' 

'  If " 

"    If  ' 

'     2  ins 

Percent. 
.  4 
.  11 
.  16 
.  18 
.  27 
.   16 


If,  however,  the  tuft  of  cotton  were  reduced  in  smoothing  out  till  the 
lengths  below  1  in.  were  eliminated,  the  resulting  fibers  would  show  a 
different  and  evidently  incorrect  appearance,  for  the  resultant  measure- 
ments would  be: 


418     THE   PHYSICAL  STRUCTURE  AND   PROPERTIES  OF   COTTON 


Percent. 

Fibers  of  1    in.  to  1|  in 26 

"        11     "     U  " 40 

"       1|     "     If  " 23 

"        If     "     2  ins 11 

which  is  quite  a  different  proposition  from  a  spinner's  point  of  view. 
It  is  quite  within  the  range  of  probabilities  that  a  proportion  of  the  longer 
fibers  would  also  be  discarded  in  the  smoothing  process. 

Conamercial  stapling  may  be  considered  as  a  sorting  of  the  fibers  in 
length,  with  the  elimination  of  unsuitable  hairs,  and  in  this  extraction  lies 

its  inherent  weakness. 
Every  machine  neces- 
sary in  the  preparation 
and  spinning  of  cotton 
may  also  reasonably 
l^e  considered  a  sorter, 
since  it  will  reject  cer- 
tain lengths  of  fiber, 
although  replacing 
them  by  similar  ones 
made  on  the  premises. 
The  practical  spinner 
knows  or  can  easily 
ascertain  in  a  varying 
degree  whether  his 
estimate  of  the  fiber 
in  the  "  raw  "  is  con- 
firmed or  otherwise  by 
the  resultant  sliver  or  yarn,  but  there  are  many  variants  to  be  considered, 
including  his  temperament  at  the  time  of  selecting,  and  the  effect  of  the 
machinery  on  that  particular  type  of  cotton. 

To  remove  as  effectively  as  possible  the  results  of  the  personal  equation, 
Dr.  Lawrence  Balls  has  invented  a  mechanism  which  will  sort  a  small 
amount  of  cotton  into  its  different  component  parts  in  order  of  their 
length.  This  novel  device  is  appropriately  named  the  "  Sledge  Pattern 
Sorter,"  and  is  elaborately  described  in  a  handbook  issued  by  the  Fine 
Cotton  Spinners  and  Doublers'  Association  Experimental  Department. 
While  this  "  sorting  "  apparatus  is  based  on  the  drafting  function  of  a 
series  of  rollers,  it  differs  from  the  ones  in  use  in  the  spinning  technique, 
in  so  far  as  the  latter  have  an  equalising  effect  on  the  various  fiber  lengths 
as  they  occur  (a  mixing  of  the  different  hairs),  and  the  purpose  of  the 
"  sorter  "  is  a  fractionating  one,  separating  the  shorter  from  the  longer 
and  retaining  the  whole  collection.     Its  inception  arose  from  a  need  of  a 


Fig.  187.— Sledge  Pattern  Sorter, 
dismantled. 


Front  view  partially 


MEASUREMENT  OF  COTTON   STAPLE 


419 


method  which  would  measure,  with  reasonable  and  definite  accuracy, 
the  length  of  every  hair  in  a  large  number  of  hairs  (these  being  themselves 
a  true  sample),  would  work  without  subjective  error,  be  reasonably  fool- 
proof, and  yet  complete  the  test  in  a  few  minutes.  The  sorter,  we  are  told, 
fulfills  these  requirements. 

The  instrument  consists  of  a  small  frame,  partly  sliding  (as  a  sledge), 
partly  rolling  on  two  rear  wheels,  along  a  6-ft.  strip  of  black  plush.  The 
plush  serves  to  comb  off  and  to  retain  the  sorted  hairs,  while  the  carriage 
contains  all  the  operating  mechanism;  in  addition  it  carries  the  feed  box 
into  which  the  prepared  sliver  of  cotton  is  placed  and  presented  to  the 
feed  rollers.  The  cotton  to  be  tested  is  prepared  by  carding,  to  disentangle 
the  hairs,  and  by  drawing,  smoothing,  or  parallelising  them  into  a  sliver, 
to  render  it  in  a  con- 
dition to  be  presented 
to  the  feed  rollers  and 
to  free  each  fiber  to 
the  fractionating  ac- 
tion of  the  intermedi- 
ary and  delivery  roll- 
ers. These  operations 
may  be  performed  by 
hand,  care  being  taken 
that  in  each  process 
all  the  fibers  are  re- 
tained. The  amount 
of  cotton  to  be  opera- 
ted on  in  the  sorter 
must  not  exceed  7 
grains  on  a  length  of 
8  ins. 

There  is  deposited  on  the  plush  a  tuft  of  cotton  2|  ins.  in  length  extended 
over  approximately  72  ins.  The  short  fibers  are  the  first  to  escape  on 
the  lower  side  of  the  delivery  rollers,  the  long  ones  will  be  the  last, 
and  the  intermediate  lengths  will  appear  on  the  plush  at  various  points 
between,  and  each  one  will  appear  on  the  plush  separate  and  distinct 
from  zero  to  the  termination  of  the  traverse.  To  indicate  these  lengths 
a  calibrated  tape  is  stretched  from  end  to  end  along  the  plush,  and  is 
divided  into  distances  representing  iV  in.  or  1  mm.  These  distances  are 
proportional  to  the  draft  of  2|  to  72. 

While  this  apparatus  doubtless  has  great  value  from  an  ex- 
perimental point  of  view,  it  is  not  so  useful  in  a  practical  way 
in  the  cotton  mill  for  determining  the  staple  of  various  samples  of 
cotton  from  the  bale  before  purchase,  as   the   apparatus  requires  the 


Fig.  188. — Sledge  Pattern  Sorter.    Plan  view,  showing 
deposit  of  fibers  on  plush. 


420     THE   PHYSICAL  STRUCTURE   AND   PROPERTIES   OF   COTTON 

use  of  a  prepared  sliver  which  cannot  be  obtained  witli  a  small  sample 
off-hand. 

Another  form  of  instrument  for  measuring  the  length  of  cotton  staples  is 
the  Baer  apparatus  (Fig.  189).  It  consists  of  a  still  frame  with  vertical 
slides,  in  which  are  placed  nine  fine  combs  of  steel  pins  on  brass  bars. 
These  combs  can  be  held  in  position  at  the  top  of  the  slides  by  means  of 
two  steel  pins.  Over  the  nine  combs,  and  fitted  to  fall  between  the  back 
four,  are  three  other  combs.  With  this  apparatus  is  also  supplied  a  pair 
of  wide-jawed  tweezers  for  taking  up  the  fibers,  a  small  wooden  rake  for 
putting  the  fibers  in  the  wire  combs,  and  a  needle  for  equalising  and 
parallelising  the  fibers  when  these  are  placed  on  the  velvet-covered  plate. 

The  sample  of  cotton  which  should  be  stretched  and  doubled  with  the 
fingers  and  then  slightly  twisted  so  that  it  resembles  a  strip  of  I's  count 


Fig.  189. — Baer  Apparatus  for  Measuring  Cotton  Staples. 

about  2j  ins.  long — is  placed  on  the  left  side  of  the  apparatus  across  the 
bottom  combs.  The  point  of  this  strip  must  stick  out  about  1  in.  behind 
the  apparatus.  The  apparatus  is  then  turned  around  so  that  its  back  is 
toward  the  operator,  who  seizes  the  projecting  point  of  the  sample  with  the 
tweezers  and  draws  out  the  fibers.  To  clean  them  he  draws  the  fibers 
several  times  through  the  last  comb  and  then  lays  them  to  one  side  on 
the  bottom  combs,  where  they  can  afterward  be  caught  by  the  fine  upper 
combs.  In  doing  this  the  tweezers  should  be  in  contact  with  the  last  comb. 
The  operation  is  repeated,  taking  only  the  extremities,  until  all  the  fibers 
have  been  selected,  cleaned,  and  laid  out  on  the  combs.  The  fibers  are 
then  thrust  into  the  combs  with  the  small  wooden  rake.  The  three  upper 
combs  are  now  placed  in  position,  the  teeth  passing  through  the  prepared 
strip.  Again  the  apparatus  is  turned  around  so  that  the  front  of  the 
apparatus  is  toward  the  operator.  A  chalk  line  is  drawn  on  a  velvet- 
covered  plate  to  form  a  base  line.     If  any  fibers  project  beyond  the  first 


STAPLE   OF   COMMERCIAL  COTTONS 


421 


comb  the  longest  of  these  is  seized  by  the  tweezers,  drawn  out,  and  placed 
on  the  left  of  the  plate.  This  operation  continues,  combs  being  dropped 
out  of  the  way  as  the  longer  fibers  are  removed.  Finally  the  upper  combs 
are  successively  removed  with  the  lower  ones  until  the  last  lot  of  fibers  are 
placed  upon  the  velvet. 

The  object  of  the  apparatus  is  to  assist  in  making  a  selection  of  fibers 
by  length  from  a  sample,  with  the  object  of  arranging  them  so  that  an 
accurate  diagram  may  be  produced.  This  diagram  is  derived  by  spreading 
the  fibers,  as  described  below,  on  an  aluminium  plate  covered  with  black 
velvet.  But  over  this  diagram  of  fibers  may  be  placed  a  sheet  of  glass 
graduated  in  inches  and  fractions,  and  accurate  measurements  and  per- 
centages can  thus  be  derived.  Still  another  method  is  to  spread  over  the 
diagram  a  sheet  of  transparent  squared  paper  upon  which  the  outline  of 
the  diagram  can  be  traced  and  a  permanent  record  of  the  sample 
taken. 

6.  Staple  of  Commercial  Cottons. — Hannan  gives  the  following 
varieties  and  qualities  of  cotton  to  be  met  with  in  commerce : 


Types. 

Variety. 

Length, 
Inches. 

Diam- 
eter, 
Inch. 

Counts. 

Use. 

Properties. 

Sea-island.  . 

Edisto 

2.20 

0.00063 

300-400 

Warp 
or  weft 

Long,  fine  silky,  and 
of  uniform  diame- 
ter 

Florida 

1.85 

0.00063 

150-300 

Do. 

Shorter,  but  similar  to 
above 

Fiji 

1.75 

0.00063 

100-250 

Do. 

Less  uniform  in 
length,  but  silky 
and  cohesive 

Tahiti 

1.80 

0.00063 

100-250 

Do. 

Good,  fine,  and  glossy 
staple 

Egyptian.. . 

Brown 

1.50 

0.00070 

120-down 

Do. 

Long,  strong,  highly 
endochromatic 

Gallini 

1.60 

0.00066 

250-down 

Warp 

High-class  staple  of 
good  strength 

Menouffieh . . . 

1.50 

0.00066 

200-down 

Weft 

Of  good  staple  and 
luster 

Mitafifi 

1.25 

0.00066 

100 

Warp 
or  weft 

Fairly  good  staple 

White 

1.00 

0.00078 

70 

Do. 

Pearly  white,  good 
long  staple 

Peruvian. .. 

Rough 

1.25 

0.00078 

50-70 

Warp 

Strong,  woolly,  and 
harsh  staple 

Smooth 

1.00 

0.00078 

50-70 

Weft 

Less  woolly,  and  soft- 
er staple 

422      THE   PHYSICAL  STRUCTURE   AND   PROPERTIES   OF  COTTON 


Diam- 

I 

Types. 

Variety. 

Length, 
Inches. 

eter, 
Inch. 

Counts. 

Use. 

Properties. 

Peruvian.  .  . 

Red 

1.25 

0.00078 

40-50 

Warp 

Color  weaker  and 
harsher  than  brown 
Egyptian 

Brazilian . . . 

Pernambuco . . 

1.50 

0.00079 

50-70 

Warp 

Strong  and  wiry 

Maranham . . . 

1,15 

0.00079 

50-60 

Do. 

Harsh  and  wiry 

Ceara 

1.15 

0.00079 

60 

Weft 

Good,  white,  and  co- 
hesive staple 

Paraiba 

1.20 

0.00079 

50-60 

Warp 
or  weft 

Fairly  strong,  harsh, 
of  good  color 

Rio  Grande. . . 

1.15 

0.00079 

40-50 

Weft 

Soft,  white,  and  harsh 
staple 

Maceio 

1.20 

0.00084 

40-60 

Warp 

or  weft 

Soft,  phable,  and  good 
for  hosiery 

Santos 

1.30 

0.00084 

50-60 

Weft 

Exotic  from  American 
seed,   white  and 
sUky  staple 

Bahia 

40-50 

Warp 
or  weft 

Fairly  strong,  but 
harsh  and  wiry 

American . . . 

Orleans 

1.1 

0.00077 

34-46 

Do. 

Medium  length, 
pearly,  white 

Texas 

1.05 

0.00077 

32-40 

Do. 

Similar  to  above, 
rather  harsher  and 
more  glossy 

Allanseed .... 

1.20 

0.00077 

50-60 

Warp 

Good,  white,  long; 
blends  with  brown 
Egyptian 

Mobile 

1.00 

0.00076 

40-50 

Warp 
or  weft 

Even-rimning  staple, 
soft  and  cohesive 

Norfolks 

1.00 

0.00076 

40-50 

Weft 

Used  for  Oldham 
counts  of  50's 

St.  Louis 

0.90 

0.00076 

30-32 

Warp 

Staple  irregular, 
glossy,  but  short 

Roanokes .... 

0.90 

0.00076 

30-34 

Do. 

A  white  and  strong 
staple 

Boweds 

36 

Weft 

Similar  to  uplands 

Benders 

1.10 

0.00077 

60 

Warp 

Strong,  creamy  or 
white,  for  Turkey- 
red  dyes 

Memphis .... 

1.00 

0.00077 

40-50 

Do. 

Bluish  white,  for  extra 
hard  twists 

Peelers 

1.25 

0.00077 

60-80 

Weft 

Long,  silky,  fine  sta- 
ple; adapted  for 
velvets,  etc. 

Uplands 

1.00 

0.00077 

36-40 

Do. 

Glossy  when  clean, 
apt  to  be  dull, 
sandy,  and  leafy 

STAPLE   OF   COMMERCIAL  COTTONS 


423 


Types. 

Variety. 

Length, 
Inches. 

Diam- 
eter, 
Inch. 

Counts. 

Use.    . 

Properties. 

American . . . 

Alabama 

0.90 

0.00077 

26-30 

Warp 
or  weft 

Short  staple,  of  less 
strength,  varying 
color 

Linters 

8-10 

Weft 

Short-stapled  gin 
waste 

Tennessee 

0.90 

0.00077 

28 

Warp 
or  weft 

Of  varying  length  and 
color 

Greek 

Smyrna 

1.25 

36-40 

Warp 

Harsh  and  strong; 
adapted  for  double 
yarns 

African 

Lagos 

0.80 

20-26 

Weft 

Dull  and  oil-stained, 
irregular  in  length 
and  strength 

West  Indian 

Carthagena.. . 

1.50 

26 

Warp 

From  exotic  seeds ; 
fairly  strong 

La  Guayran . . 

1.20 

40 

Warp 
or  weft 

Irregular  and  short, 
but  silky  staple 

China 

China 

1.00 

30 

Weft 

Harsh,  short,  and 
wliite 

Austrahan . , 

Queensland.. . 

17.5 

0.00066 

120-200 

^^'arp 
or  weft 

Long,  white,  silky, 
fine  diameter 

East  Indian. 

Oomrawuttee. 

1.00 

0.00083 

26-32 

Warp 

Short,  strong,  and 
white 

East  Indian. 

Hingunghat.  . 

1.00 

0.00083 

28-36 

Weft 

Best  white  Indian  sta- 
ple 

Comptah .... 

1.05 

Warp 
or  weft 

Generally  dull  and 
charged  with  leaf 

Broach 

0.90 

28-36 

Weft 

Like  Hingunghat, 
gives  good  white 
weft 

Dharwar 

1.00 

28 

Warp 

Exotic  from  American 
seeds 

Assam 

0.50 

15-20 

\^"arp 

White,  but  harsh,  to 
blend  with  other 
cottons 

Bengals 

0.80 

20-30 

Warp 
or  weft 

Dull  and  generally 
charged  with  leaf 

Bilatii 

0.50 

10-20 

Do. 

Weak,  brittle,  and 
coarse 

Dhollerah. .  .  . 

0.70 

15-20 

Do. 

Strong,  dvill,  and  co- 
hesive 

Surat 

0.60 

10-15 

Do. 

Dull  and  leafy,  often 
stained 

Scinde 

0.50 

to  10 

Do. 

Very  strong,  dull, 
short,  and  poor  sta- 
ple 

424      THE  PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  COTTON 


Types. 

Variety. 

Length, 
Inches. 

Diam- 
eter, 
Inch. 

Counts. 

Use. 

Properties. 

East  Indian. 

Tinnevelly .  .  . 

0.80 

24-30 

Do. 

Lustrous  white,  soft, 
and  adapted  for 
hosiery 

Bhownuggar.. 

1.00 

28-30 

Warp 

White  when  clean ; 
often  leafy  and 
dirty 

Cocoanada . . . 

0.70 

10-14 

Brown 

weft 

Brown  and  dull;  used 
as  quasi-Egyptian 

Bourbon 

1.00 

30 

Weft 

Exotic;  of  good  sta- 
ple; scarce 

Khandeish .  .  . 

0.80 

0.00083 

20-26 

Warp 
or  weft 

Similar  in  class  to 
Bengal 

Madras  or 

0.70 

15-20 

Do. 

Used  for  low  yarns  in 

Westerns 

coarse  toweling, 
etc. 

Rangoon 

0.60 

to  10 

Warp 
or  weft 

Weak,  dull,  often 
stained  and  leafy 

Kurrachee.  .  . 

0.90 

28 

Do. 

Fairly  strong,  dull, 
and  leafy 

Italian 

Calabria 

0.90 

26-28 

Do. 

Fairly  strong,  irregu- 
lar and  dull,  leafy 

Turkey 

Levant 

1.25 

0.00077 

36-40 

Warp 

Harsh,  strong,  and 
white 

Monie  gives  the  tables  on  pages  425  to  427  descriptive  of  the  principal 
commercial  varieties  of  cotton.  As  the  descriptions  given  in  these  tables 
vary,  in  some  respects,  quite  considerably  from  the  preceding  tables  of 
Hannan,  it  is  probably  best  that  both  should  be  given  for  comparison. 

Monie  remarks  in  connection  with  this  table  that  it  will  be  observed 
that  the  Fiji  and  Tahiti  Sea-island  cottons  are  the  most  irregular  in  the 
length  of  their  fibers,  the  extreme  variation  in  both  being  half  an  inch. 
As  long  and  short  cotton  never  incorporate  well  together  nor  adapt  them- 
selves to  the  production  of  a  yarn  regular  in  appearance  and  strength,  it 
is  easy  to  understand  that  they  are  relatively  wasteful  cottons  to  work. 
In  any  spinning  mill  where  they  are  used,  it  will  be  found  that  the  quan- 
tity of  "  fly,"  "  combings,"  and  "  flat  waste  "  made  at  the  various  machines 
is  very  great,  and  the  reason  of  this  is  that  in  any  cotton  where  the  fibers 
are  of  different  lengths,  the  long  and  strong  will  have  a  tendency  to  throw 
out  the  short  and  weak.  The  cotton  which  presents  the  greatest  regularity 
is  the  Orleans.  In  comparing  the  diameters  of  various  cottons  with  their 
lengths,  it  will  be  found  that  the  longest  cottons  are  usually  the  finest. 


STAPLE   OF  COMMERCIAL  COTTONS 


425 


22 

o 

Length  and  small  diameter;  silkiness;  free  from 
impurities ;  contains  some  short  and  undeveloped 
fiber 

6 
Q 

6 
Q 

d 

Similar  to  preceding,  but  weaker  and  containing 
larger  percentage  of  unripe  fiber 

s 

bCM 

il 

^f 

O    O 

O 

Not  so  fine  or  silky  as  Sea-island  proper;  of  a  light 
golden  tint;    fiber  moderately  strong;    apt  to 
contain  much  dirt 

1 

o  - 

r^ 

03  a 

&^ 

•  Sg 
§2 

S| 

._  o 

3^ 

o3   irf 

§^ 

CO 

o 

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w 

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a) 

c 

c3 

C3 
03 

bC 

s 

in 
u 
'o 

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O 

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(3 
o3 

,::: 

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c3 
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■*^ 
i:  =« 
^^ 

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CO   3 

s^ 

!h    CO 

Is 

O    o3 

£8 

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1 

"c 
o 

"oS 

2§ 
^^ 

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!-    o3 
0-2 

la 

Class : 
T  =  Twist. 
W  =  Weft. 

d 

^ 

d 
Q 

d 

* 

H 

^ 

»3 

o 
o 

CO 

o 
o 

1 

1— 1 

8 

(M 

1 

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lO 
1—1 

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1—1 
1 

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'^ 

1—1 

1 

o 

00 

o 

CO 
1—1 

1 

8 

1—1 

o 
o 

o 

1 

o 

O 
1 

o 

o 

Mean 

Diameter 

of 

Fiber, 

Inch. 

CO 
o 
o 

8 

o 

CO 
CO 

o 
o 
o 

o 

§ 

o 
o 
o 

d 

CO 
o 
o 
o 

d 

CO 

o 
d 

1—1 
<^ 

CO 

d 

00 
CO 
t^ 

o 

o 

o 

d 

CO 

o 

o 
o 

d 

Oi 

CO 

o 
d 

Ex- 
treme 
Varia- 
tion, 
Inch. 

d 

CO 
o 

o 
d 

CO 
d 

CO 

d 

o 
d 

CO 
d 

1—1 

CO 

d 

1— 1 

CO 

d 

d 

S-t 

§1 

'^  1— 1 

1—1 

1—1 

1—1 

CO 

1—1 

CO 

T-K 

o 
1—1 

1—1 
CO 

1— ( 

CO 
1— ( 

00 
1— 1 

1-4 

1— 1 

o 

1— < 

1—1 

CO 
1—1 

1— ( 

1—1 

1— H 

1—1 
1—1 

(M 

CO 
1—1 

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C5 

CO 

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426      THE   PHYSICAL  STRUCTURE   AND   PROPERTIES  OF   COTTON 


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STAPLE  OF   COMMERCIAL  COTTONS 


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428     THE  PHYSICAL  STRUCTURE   AND   PROPERTIES   OF   COTTON 

Hohnel  gives  the  following  table  for  the  thickness  of  different  varieties 
of  cotton : 

Thickness  in 

North  American:  Microns. 

Sea-island 14 

Louisiana  and  Alabama 17 

Florida 18 

Upland  and  Tennessee 19 

Southern  and  Central  American 15-21 

Average 19 

East  Indian: 

Dhollerah  and  Bengal 20 

Madras 28 

Chinese: 

Nankin 25-40 

Egyptian: 

Makko 15 

Levantine 24 

European: 

Spanish 17 

Italian 19 

According  to  Wiesner,  the  thickest  part  of  the  cotton  fiber  is  not 
directly  at  the  base,  but  more  or  less  toward  the  middle  (Fig.  190).  He 
gives  the  following  measurements  of  thickness  at  different  parts  of  the 
fibcn-: 


G.  arbor  cum, 

G.  acuminatum, 

G.  herbaceum, 

Position. 

25  Mm.  Long, 

28  Mm.  Long, 

25  Mm.  Long, 

Microns. 

Microns. 

Microns. 

Point 

0 

0 

0 

1 

8.4 

4  2 

4.2 

2 

21 

21.6 

5.8 

3 

29 

16.8 

10.0 

4 

25 

29.4 

16.8 

5 

29 

17.0 

21.0 

6 

25 

21.1 

10.9 

7 

21 

21.1 

21.0 

Base 

Mean 

17 

21.0 

16.8 

19.5 

16.9 

12.5 

The  length  of  the  cotton  fibers  attached  to  a  single  seed  is  by  no  means 
constant.  The  longest  fibers  usually  appear  at  the  crown  of  the  seed, 
while  the  shortest  occur  at  the  base.  There  is  also  frequently  an  under- 
growth of  very  short  fuzzy  fibers.     The  cotton  seed  is  more  or  loss  egg- 


STAPLE   OF   COMMERCIAL   COTTONS 


429 


shaped,  and  the  longest  fibers  occur  on  the  broad  end,  and  the  shortest 
on  the  narrow  end.  At  the  same  time,  the  seed  is  also  covered  with  an 
undergrowth  of  short  hairs  (2  to  3  mm.  in  length)  which  are  generally 
colored  yellow,  brown,  or  a  dirty  green,  and  are  very  thin-walled  and  weak. 
This  undergrowth  occurs  as  a  fine  down  either  over  the  entire  seed  as  in 
Gossypium  flavidum,  arhoreum,  and  hirsutum,  or  merely  on  the  point 
and  base  of  the  seed,  as  with  G.  conglomeratum  and  religiosum. 

In  ginning  the  purpose  is  not  to  remove  the  very  short  fibers,  but  at 
best,  more  or  less  of  them  appear  with  the  ginned  cotton.  These  short 
fibers  are  termed  "  neps,"  and  their  presence  in  any  considerable  amount 


Fig.  190.  Fig.  191. 

Fig.  190. — Cotton  Fiber.     A,  Middle  portions  of  fiber;  B,  points  or  ends  of  fiber. 
Fig.  191. — Root  of  Cotton  Fiber.     Showing  the  irregular  fracture  caused  by  the  fiber 
being  torn  from  the  seed.     (Micrograph  by  author.) 

materially  affects  the  commercial  value  of  the  cotton.  This  short  under- 
growth of  neps  appears  to  be  made  up  of  incompletely  developed  or  imma- 
ture fibers,  though  neps  may  also  arise  through  excessive  breaking  of  fibers 
by  imperfect  manipulation  in  the  carding  and  spinning  processes. 

Bowman  gives  the  following  table  showing  the  extreme  variation  in  the 
length  and  diameter  of  different  kinds  of  cotton: 


Cotton. 

Variation  in 
Length,  Inch. 

Variation  in 
Diameter,  Inch. 

American  (Orleans) 

Sea-island 

0.28 
0.39 
0.28 
0.22 
0.25 

0.000390 
0.000360 
0.000340 
0.000130 
0.000391 

Brazilian 

Egyptian 

Indian  (Surat) 

430     THE   PHYSICAL   STURCTURE   AND   PROPERTIES   OF   COTTON 


According  to  the  measurements  of  Wiesner,  the  average  width  (diameter 
of  the  broadside)  of  the  various  kinds  of  cotton  are  as  follows : 

Microns. 

Gossypium  herbaceum 18.9 

' '  harhadense 25 . 2 

* '  conglomeraium 25 . 5 

*  *  acuminatum 29 . 4 

*  *         arboreum 29 . 9 

*  *  religiosum 33 . 3 

"         flavidum 37.8 

Bowman  calls  attention  to  the  fact  that  Egyptian  cotton  is  the  most 
regular  in  both  length  and  diameter;    while    Sea-island  cotton,  though 


Sea  Island 
Long 

Sea  Island 
Short 

Haiti 

Tahiti 

New 
Orleans 

Texas 

Peru 

Hiugung- 
hat 

Cocanadah 

Bengal 

mm 

O.J 

50 
45 
40 
35 
30 

— 

■ 

30 
15 

10 

— 

Fig.  192. — Showing  Comparative  Lengths  of  Different  Cottons. 

ima.)     (After  Lecomte.) 


(Maxima  and  Min- 


possessing  the  greatest  length  and  fineness  of  staple,  also  exhibits  the 
greatest  variation.  It  is  also  noticeable  that  the  variation  in  the  diameter 
is  proportionately  very  much  larger  than  the  variation  in  the  length. 
Bowman  also  gives  an  interesting  comparison  of  the  size  of  the  individual 
cotton  filler  with  objects  of  common  experience.  If  a  single  fiber  of 
American  cotton  were  magnified  until  it  becomes  1  in.  in  diameter,  if; 
would  be  a  little  over  100  ft.  long,  while  a  Sea-island  fiber  of  the  same 
diameter  would  be  about  130  ft.  It  requires  from  14,000  to  20,000  individ- 
ual fibers  of  American  cotton  to  weigh  1  grain,  hence  there  are  about 
140,000,000  in  each  pound,  and  each  fiber  weighs  on  an  average  only 


PHYSICAL  FACTORS   FOR   COTTON   FIBER 


481 


about  0.00006  grain.     If  the  separate  fibers  contained  in  1  lb.  were  placed 
end  to  end  in  a  straight  line,  they  would  reach  2200  miles.^ 

Hohnel  gives  the  follo\\ing  table  of  the  different  varieties  of  cotton 
arranged  according  to  their  length  of  staple : 


Cfossypium  barbadense 


(Sea-island) 4 .  05  cm 

"  (Brazilian) 4.00 

"  (Egyptian) 3.89 

vitifolium  (Pernambuco) 3 .  59 

conglomeratum  (Martinique) 3.51 

acuminatum      (Indian) 2 .  84 

arboreum  (Indian) 2 .  50 

herbaceum  (Macedonian) 1 .82 

(Bengal) 1.03 


7.  Physical  Factors  for  Cotton  Fiber. — Dr.  W.  L.  Ball  gives  the  follow- 
ing interesting  data  concerning  the  physical  properties  of  the  cotton  fiber: 


Commonest  length,  inches 

Staple  length,  mches 

Ribbon  width  (mm.XlO"^) 

Weight  per  cubic  meter  of  hair 

(mgs.XlO-5) 

Hair  break,  grams 


Sea-island 


2.25 
154 

97 
3.92 


Egyptian 


1.37 
1.75 
194 

136 
4.70 


American, 


1 

1.37 
202 

171 
5.04 


Peruvian 


1.25 
1.75 
215 

255 
7.00 


Average. 


191 

165 
5.16 


Some  calculations  from  data  of  dimensions  for  weight -r- length:  single 
hair,  average  denier  is  2;  tenacity  is  2.0  to  3.5  grams  per  denier  (similar 
to  boiled-off  silk).  Taking  the  filament  of  cctton  as  a  cylinder  (mean 
diameter  as  indicated) :  0.2  mgm.  to  1  meter  length,  is  equal  to  0.315  mm.*^, 
and  taking  the  cotton  substance  at  1.53  sp.  gr.,  volume  of  0.2  mgm.  would 

'  Burkett  (Cotton,  p.  328)  gives  the  following  data  concerning  the  manufactured 
value  of  one  pound  of  raw  cotton  worth  10  cents : 

1§  yards  of  denim  worth  18  cents. 

4  yards  sheeting  worth  20  cents. 

4  yards  bleached  mushn  worth  32  cents. 

7  yards  caUco  worth  35  cents. 

6  yards  gingham  worth  45  cents 

10  yards  shu-twaists  worth  $1.50. 

10  5'ards  lawn  worth  $2.50. 

25  handkerchiefs  worth  $2.50. 

56  spools  No.  40  sewing  thread  worth  $2.80. 

These  figures,  of  course,  are  only  relative  averages  for  the  year  1910. 


432     THE   PHYSICAL  STRUCTURE   AND   PROPERTIES  OF  COTTON 

be  0.L30  mm.'^,  or  40  percent,  volume  of  air  space  would  be  0.185  mm.^, 
or  60  percent.     For  cotton  yarn  of  lOO's  count: 

Diameter  of  thread 0.1  mm. 

Volume  per  10  meters 78 . 6  mm^. 

Weight  per  10  meters 60 . 0  mgm. 

The  volume  of  yarn  cylinder  represents  approximately  50  percent  cotton 
substance  and  50  percent  air  space,  and  the  apparent  surface  of  the  yarn 
cylinder  is  approximately  550  cm^. 

Pierce  ^  gives  the  following  interesting  physical  factors  for  individual 
cotton  fibers,  taken  as  an  average  of  a  large  number  of  tests : 


Variety. 

Length, 
Cms. 

Rigidity, 
Dynes  Sq.  Cm. 

Weight, 
10"''  Grams. 

Sea-island 

Egyptian  nubarri 

Egyptian  affifi 

Peruvian  hybrid 

4.2-5 
3.6 
3.1 
2.9 
2.6 
2.6 
2.4 
2.3 
2.2 
1.7 

0.010-0.021 
0.024 
0.032 
0.063 
0.045 
0.039 
0.061 
0.045 
0.071 
0.111 

5.9-6.7 
6.3 
5.6 

7.7 

Trinidad  native 

4.9 

Upland  Memphis 

5  3 

American  FGM 

Upland  cross 

Pernams 

Indian  Bharat 

5.6 
5.0 
6.7 

5.8 

The  rigidity  of  the  fiber  is  the  torque,  or  twisting  force,  in  the  fiber 
when  1  cm.  is  given  one  complete  twist. 

Pierce  also  furnishes  the  following  physical  factors  for  the  cotton  fiber, 
that  may  be  calculated  approximately  from  the  staple  length: 

Staple  length L  (in  cms.) 

Fiber  mass 5.8X  10"^  grams 

Mass  per  centimeter (5  .S/L)  XlO"^  grams 

Wall  cross-section (3.9/L)  X10~^  sq.  cms. 

Rigidity 0 . 3/L2  dynes  cm.'^ 

Breaking  load 20/L  grams. 

Fibers  in  yarn  section lOOOL/N  or  (U'/iN)  ><10« 

Initial  couple  in  yarn S00t/LN  =  300p/LVN 


The  density  of  the  cotton  fiber  is  assumed  as  1.51;  N  is  the  count  of 
the  yarn,  L"  is  the  staple  length  in  inches,  t  is  the  twist,  and  p  the  spinning 
factor  t/VN. 

1  Jour.  Text.  Inst.,  1923,  p.  7. 


ANATOMICAL  STRUCTURE 


433 


8.  Anatomical  Structure. — From  its  behavior  with  a  solution  of 
aminoniacal  copper  oxide,  the  cotton  fiber  appears  to  consist  of  four  distinct 
parts  structurally.  When  treated  with  this  solution  and  examined  under 
the  microscope,  the  fiber  is  seen  to  swell,  but  not  uniformly;  it  seems  that 
at  regular  intervals  there  are  annular  sections  which  do  not  swell.  The 
result  is  that  the  fiber  assumes  the  form  of  a  distended  tube  tied  at  intervals 
somewhat  after  the  manner  of  a  string  of  sausages  (Fig.  193).  Hohnel 
considers  these  ligatures  as  merely  parts  of  the  cuticle;  he  explains  their 
formation  by  the  fiber  swelling  so  considerably  as  to  rupture  the  undis- 
turbed cuticle,  which  in  places  adheres  to  the  fiber  in  the  form  of  irregular 
shreds  which  are  visible  only  with  difficulty.  In  other  places  where  the 
rupture  occurs  obliquely  to  the  length  of  the  fiber,  the  cuticle  becomes 


Fig.  193. — Cotton  Swollen  in  Schweitzer's  Reagent.     (Herzog.) 

drawn  together  in  annular  bands  surroimding  the  fiber,  while  between 
these  rings  the  much-distended  cellulose  protrudes  in  the  form  of  globules 
(Fig.  194).  The  inner  membrane  or  canal  which  persists  after  the  rest 
of  the  fiber  has  dissolved  is  an  exceedingly  thin  tissue  of  dried  protoplasm 
I  which  was  contained  in  the  living  fiber. 

According  to  Hohnel,  the  lumen  of  cotton  is  quite  small,  because  the 
cell-walls  of  the  back  and  front  sides  lie  close  against  one  another.  It  is 
filled  partly  with  air  and  partly  with  an  exceedingly  thin  membrane  of 
dried  protoplasm  which  was  contained  in  the  living  fiber.  This  membrane, 
apparently  consisting  of  dried  albumen,  like  the  cuticle,  remains  undis- 
solved after  the  solution  of  the  cellulose  in  either  ammoniacal  copper 
oxide  or  concentrated  sulfuric  acid.  As  the  fiber  in  dissolving  becomes 
shortened  by  40  to  60  percent,  its  contents  assume  a  peculiar  appearance, 
exhibiting  crisscross  markings  by  reason  of  the  folds  which  are  formed. 

On  bleached  cotton  the  cuticle  may  be  alftiost  entirely  lacking,  and 
hence  srch  fibers  will  not  exhibit  the  characteristic  appearance  above 


434     THE   PHYSICAL  STRUCTURE  AND   PROPERTIES  OF   COTTON 


mentioned.  When  the  fiber  has  become  much  swollen  by  the  action  of  the 
reagent  it  soon  begins  to  dissolve,  whereupon  the  walls  of  the  central  canal 
are  seen  quite  prominently;  the  dissolving  action  proceeds  rapidly,  but 
apparently  there  is  a  thin  cuticular  tissue  surrounding  the  fiber  which 
resists  the  action  of  the  solvent  for  a  much  longer  time  than  the  inner 
portion.  The  walls  of  the  central  canal  also  resist  the  action  of  the  liquid 
to  even  a  greater  extent  than  the  external  tissue;  the  annular  contracted 
ligatures  also  persist  after  the  rest  of  the  fiber  has  dissolved.     Thus  we 

have  four  structural  parts 
-W  made  evident. 

(a)  The  main  cell- 
wall,  probablj^  composed 
of  pure  cellulose,  and 
rapidly  and  completely 
soluble  in  the  reagent. 

(6)  An  external  cuti- 
cle, probably  of  modified 
cellulose,  and  more  resis- 
tant to  the  action  of  the 
reagent. 

(c)  The  wall  of  the 
central  canal,  which  re- 
sists the  solvent  power  of 
the  reagent  even  more 
than  the  cuticle, 

{(l)  The  annular  liga- 
tures    surrounding    the 

^  ,  fiber  at  intervals,  which 

Fig.  194. — Appearance  of  Cotton   Fiber  on  Treatment  .  r-         -i 

with  Schweitzer's  Reagent.    (After  Witt.)    a,  Trans-  Persist    even    alter    the 
verse  ligatures  of  disrupted  cuticle;  h,  irregular  shreds   canal-walls       have      cllS- 
of  cuticle  torn  apart;  c,  swollen  mass  of  cellulose;  d,    solved, 
walls  of  internal  canal.  The     cuticle     cannot 

always  be  seen  in  an 
equally  distinct  manner,  because  it  may  occur  thinner  or  thicker,  smooth  or 
rough.  The  thinnest  and  smoothest  is  to  be  found  on  Sea-island  cotton, 
which  comes  irom  Gossypiumbarbadetise;  while  the  coarse  varieties  of  cotton, 
such  as  Gossypium  flavidum,  arhoreum,  herbaceum,  and  religiosum,  possess  a 
hardy,  roughly  granular  cuticle.  With  this  is  connected  the  fact  that  the  latter- 
mentioned  varieties  of  cotton  yield  a  dull-looking  fiber.  A  very  remarkable 
thing  is  the  granulation  of  the  cuticle  by  the  action  of  the  air.  The 
stripes  and  other  structural  relations  which  are  to  be  noticed  on  the  cotton 
fiber  originate  principally  in  the  cuticle.  The  cellulose  membrane  itself 
shows  no  spots  of  any  kind  and  no  other  structural  peculiarities.     On  well- 


ANATOMICAL  STRUCTURE 


435 


bleached  cotton  material  (yarn,  cloth,  etc.)  the  cuticle  may  be  almost 
entirely  lacking.  For  extended  areas  over  the  fiber  the  cuticle  may  not 
be  found  at  all,  and  hence  does  not  yield  the  characteristic  phenomena 
above  mentioned  when  the  fiber  is  swollen  up  with  ammoniacal  copper 
oxide  solution. 

O'Neill  (in  1863)  first  pointed  out  this  complex  structure  of  the  cotton 
fiber.  He  says:  ''  I  believe  that  in  cotton-hairs  I  could  discern  four 
different  parts.  First,  the  outside  membrane,  which  did  not  dissolve  in 
the  copper  solution.  Second,  the  real  cellulose  beneath,  which  dissolved, 
first  swelling  out  en- 
ormously and  dilat- 
ing the  outside  mem- 
brane. Thirdly,  spi- 
ral fibers,  apparently 
situated  in  or  close 
to  the  outside  mem- 
brane, not  readily 
soluble  in  the  3opper 
liquid.  These  were 
not  so  elastic  as  the 
outside  membrane 
and  acted  as  stric- 
tures upon  it,  pro- 
ducing b  e  a  d  1  i  k  e 
swellings  of  a  most 
interesting  appear- 
ance; and  fourthly, 
an  insoluble  matter, 
occupying  the  core 
of  the  cotton-hair, 
and  which  resem- 
bled very  much  the 

shriveled  integument  in  the  interior  of  quills  prepared  for  making  pens." 
He  also  notes  that  the  insoluble  outside  membrane  was  not  evident  on 
bleached  cotton,  hence  concluding  that  either  it  had  been  dissolved  away, 
or  some  protecting  resinous  varnish  had  been  removed,  and  then  it  became 
soluble.  He  also  obtained  the  same  general  results  by  treatment  with 
sulfuric  acid  and  chloride  of  zinc  in  place  of  the  ammoniacal  copper  oxide 
solution. 

According  to  Butterworth,  who  observed  the  cotton  fiber  treated  with 
the  ammoniacal  copper  oxide  solution  under  a  magnification  of  1600 
diameters,  there  are  spiral  threads  (Figs.  195  and  196)  apparently  crossing 
and  tightl.y  bound  round  the  fiber  at  irregular  distances,  also  spiral  threads 


Fig.  195. — Cotton  Fiber  Swollen  with  Schweitzer's  Reagent. 
( X600.)  Showing  spirally  developed  lamella  in  fiber  walls. 
(Micrograph  by  author.) 


436     THE   PHYSICAL  STRUCTURE  AND   PROPERTIES   OF  COTTON 

passing  from  one  stricture  to  another;  the  core  of  the  fiber  has  a  spiral 
form,  and  in  cross-section  shows  the  presence  of  concentric  rings. 

There  appears  to  be  some  difference  in  the  action  of  ammoniacal 
copper  oxide  solution  on  fibers  of  different  physiological  structure.  Imma- 
ture or  unripe  fibers  dissolve  readily  without  exhibiting  any  structural 
differences.  The  tubular-shaped  fibers  swell  out  as  a  whole  and  finally 
dissolve  without  showing  any  structural  modifications,  except  that  in 
many  cases  an  inner  core  is  left. 

Minajeff  ^  has  studied  the  structure  of  cotton  as  shown  by  the  action 
of  concentrated  caustic  soda  solution  on  the  fiber,  particularly  with 
reference  to  the  question  of  mercerisation.  His  conclusions  may  be 
summed  up  as  follows:  (1)  The  cuticle  of  the  raw  fiber  withstands  the 
action  of  concentrated  cuprammonium  solution,  also  strong  sulfuric  acid 
and  alkalies.  The  cuticle  of  the  fiber  shows  the  same  properties,  but  less 
pronounced,  while  that  of  the  oxidised  fiber  is  weak  and  brittle.  (2)  The 
fiber  wall  swells  and  dissolves  in  cuprammonium  solution,  also  in  concen- 
trated sulfuric  acid,  with  the  formation  of  amyloid-like  bodies.  (3)  The 
inner  protoplasmic  lining  is  very  similar  in  its  reactions  to  the  cuticle. 

Examination  with  the  highest  microscopic  powers  has  not  shown  any 
cellular  structure  pertaining  to  the  cellulosic  contents  of  the  cotton  fiber; 
it  is  apparently  composed  of  fine  layers  of  spirally  laid  fibrilla?  super- 
imposed one  upon  the  other. 

The  spiral  fibrilke  occurring  in  the  cell-wall  of  the  cotton  fiber  can  be 
readily  observed  under  the  microscope  with  even  moderately  high  magnifi- 
cation in  the  case  of  cotton  rag  pulp  for  paper  manufacture.  The  cotton 
fibers  under  these  circumstances  have  been  so  broken  up  and  mechanically 
bruised  and  partially  disintegrated  that  the  individual  fibrillae  are  often 
well  separated.  Kuhn  concurs  with  the  author  in  the  opinion  that  the 
cotton  fiber  is  made  up  of  spirally  laid  fibrillse,  and  he  attributes  the 
absorptive  power  of  cotton  toward  solutions  to  the  permeable  spaces 
occurring  between  these  fibrillae.  Bowman  ^  also  calls  attention  to  this 
structure.  This  opinion,  however,  is  not  held  by  Balls,^  who  made  a  very 
extensive  investigation  on  the  structure  of  the  cotton  fiber  with  relation 
to  its  development  and  growth.  He  states  that  the  concentric  layers  of 
cellulose,  probably  delimited  from  night  to  night,  are  laid  down  on  the 
interior  of  the  delicate  cellulose  cuticle  wall,  until  a  definite  thickness  is 
reached.  Using  a  swelling  reagent  on  cotton  taken  from  dated  bolls. 
Balls  was  able  to  prove  definitely  the  presence  of  these  rings  up  to  the 
number  of  25,  with  an  average  thickness  of  about  0.4  micron  each,  corre- 
sponding with  the  number  of  days  from  the  cessation  of  growth  in  length. 

1  Zeit.  Farben-Ind.,  1907,  pp.  233,  252,  309,  3-15. 

2  Structure  of  Cotton  Fiber,  p.  105. 

'  The  Cotton  Plant  in  Egypt,  p.  84. 


ANATOMICAL  STRUCTURE 


437 


Fig.  196. — Portion  of  Fig.  195  more  Highly  Magni- 
fied. (X1500.)  The  spiral  structure  of  the 
cotton  cellulose  is  here  plainly  visible.  (Micro- 
graph by  author.) 


He  accounted  for  their  differ- 
entiation from  each  other  by 
reference  to  the  arrest  of  growth 
by  the  "sunshine  effect"  oc- 
curring in  the  middle  of  each 
day  in  Egypt.  This  spiral 
structure  of  the  cell-wall  of 
the  cotton  fiber  is  in  disagree- 
ment with  the  statement  of 
De  Mosenthal  ^  who  claims 
that  the  cellulose  of  cotton 
consists  of  minute  spherical 
granules  about  1  micron  in 
diameter.  All  the  best  au- 
thorities on  the  microscopy 
of  cotton,  however,  are  opposed 
to  this  view  of  its  structure. 

According  to  Dreaper  ^  the 
outer  sheath  of  the  cotton  fiber 
is  considered  to  be  pure  cellu- 
lose, while  the  inner  layers  are  made  up  of  secondary  cellular  deposits ;   or 

are  formed  by  a  grad- 
ual thickening  of  the 
outer  layer. 

Whether  the  sub- 
stance which  is  present 
in  the  outer  wall  of 
cotton  can  be  included 
under  the  generic  term 
of  cutin  is  a  problem 
for  chemistry.  Its  ex- 
act nature  is  unknown, 
and  research  on  the 
subject  is  awaited. 
It  is  certainly  of  a 
waxy  or  fatty  nature, 
resistant  to  acids  and 
cellulose  solvents, 
while  susceptible  to 
the  action  of  alkalies, 
which    are    said     by 


Fig.  197.— Sea-island  Cotton.     (X185.)     (Herzog.) 

»  Jour.  Soc.  Chem.  I  ml,  1904,  p.  292 
^  Chemistry  and  Physics  of  Dyeing,  p. 


12. 


438     THE  PHYSICAL  STRUCTURE   AND   PROPERTIES   OF   COTTON 


Haller  ^  to  cause  its  disappearance  in  the  process  of  mercerisation.  The 
cuticle  has  long  been  recognised  as  very  liable  to  mechanical  damage, 
and  hairs  taken  from  a  yarn  show  frequent  abrasions  and  cracks;  a  fact 
commented  on  by  Butterworth  in  1881,  and  since  apparently  overlooked. 
Such  abrasions  are  visible  in  dry  cotton  under  quite  a  low  magnification 
by  reflected  light,  as  bright  patches  with  an  almost  granular  appearance, 
while  cracks  due  to  pressure  can  best  be  seen  under  a  higher  power  if  the 
specimen  is  mounted  in  a  suitable  medium. 

One  feature  in  the  structure  of  the  cotton  fiber  which  has  been  the 
subject  of  much  discussion,  and  which  at  the  same  time  is  of  great  impor- 
tance in  the  dyeing 
and  bleaching  of  the 
fiber,  is  the  occurrence 
of  pits  or  openings  in 
the  cell- wall.  Cracks, 
running  more  or  less 
spirally  along  the  cuti- 
cle, have  been  seen  by 
several  observers,  and 
can  be  produced  at 
will  by  mechanical  ill- 
treatment  of  the  hair. 
Definite  pores  in  the 
cuticle  have,  however, 
been  observed  by  Mo- 
senthal.-  These  pits 
or  pores,  to  which  he 
gave  the  unfortunate 
name  of  Stomata,  are 
described  by  him  as 
occurring  in  oblique 
rows    as    if    they    led    into    oblique    lateral    channels. 

It  is  usually  accepted  that  the  cellulose  composing  the  primary  wall 
is  chemically  distinct  from  that  of  the  secondary  deposition.  While  the 
exact  relation  of  the  cutinous  substance  to  the  wall  is  not  known,  whether, 
for  instance,  it  is  dispersed  through  its  mass,  or  merely  forms  an  external 
coating  (which  from  the  behavior  of  the  cuticle  in  cuprammonium  seems 
likely)  there  is  evidence  to  prove  a  profound  change  in  the  chemical  com- 
position of  the  cell  sap  at  the  time  when  elongation  in  length  ceases  and 
secondary  growth  begins.  The  3'oung  hairs  are  extremely  astringent,  and 
possibly  contain  tannins,  as  they  turn  black  when  immersed  in  a  solution 
of  a  ferric  salt,  whereas  the  ripe  hairs  do  not. 

1  Text.  u.  Fdrberei  Zeit.,  1907,  p.  221.  "^Jour.  Soc.  Chem.  Ind.,  1904,  p.  292. 


198.— Upland  Cotton.     (X185.)     (Herzog.) 


MICHOSCOPY   OF   COTTON   FIBER 


439 


9.  Microscopy  of  Cotton  Fiber. — The  microscopical  characteristics  of 
the  cotton  fiber  are  so  pronounced  as  to  differentiate  it  readily  from  all 
others.  As  previously  noted,  it  presents  the  appearance  of  a  flat,  ribbon- 
like  band,  more  or  less  twisted  on  its  longitudinal  axis  (Figs.  197,  198,  and 
199).  The  edges  of  the  fiber  are  somewhat  thickened,  and  usually  present 
irregular  corrugations.  The  fiber  also  at  times  presents  the  appearance 
of  a  rather  smooth  flat  band  with  little  or  no  thickened  edges.  According 
to  Hohnel,  the  cotton  fiber  appears  as  a  broad,  finely  grained  band,  which 
is  repeatedly  twisted  about  its  axis.  In  this  case,  the  walls  are  relatively 
thin,  the  fiber  is  from  three  to  four  times  as  broad  as  it  is  thick,  and  the 
lumen  is  three  to  four 
times  as  broad  as  the 
walls.  This  is  essentially 
all  to  be  observed  in  the 
case  of  ordinary  coarse 
varieties  of  cotton  (for 
example,  the  Indian)  the 
maximum  diameter  of 
which  is  30  mm.  In  the 
case  of  finer  varieties 
(North  American,  Egyp- 
tian), especially  from  G. 
harhadense,  the  fiber  ap- 
pears only  slightl}'  or  not 
at  all  compressed,  only 
slightly  twisted  in  a  rope 
form,  relatively  very 
thick-waUed  so  that  only 
a  narrow  lumen  is  seen. 
Hence  the    fiber  looks  as 

if  it  possessed  glossy,  thickened  edges.  Often  such  kinds  of  cotton  are 
almost  cylindrical  for  considerable  distances  along  their  length,  and  in 
some  measure  resemble  linen  fibers. 

The  twist  of  the  fiber  does  not  appear  to  be  continuous  in  one  direction ; 
a  portion  of  a  fiber  may  be  twisted  axially  to  the  right,  then  exhibit  a 
flattened  portion  without  any  twist  at  aU,  then  again  show  an  axial  twist 
to  the  left.  The  twist  of  the  cotton  fiber  appears  to  be  a  character  acquired 
through  cultivation,  as  it  is  not  possessed  by  wild  cotton.  IMonie  ^  explains 
the  twist  in  cotton  as  follows:  The  rotary  motion  begins  with  the  process 
of  vacuation  in  the  fiber,  caused  by  the  withdrawal  of  some  of  the  fluid 
in  the  fiber  when  the  seed  begins  to  ripen,  and  as  this  is  affected  slowly 
and  progressive!}',  beginning  at  the  extremity  farthest  from  the  seed  and 

1  The  Cotton  Fiber,  p.  25. 


Fig.  199.— Indian  Cotton.     (Herzog.) 


440     THE  PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  COTTON 


gradually  receding  toward  the  base,  the  free  end  or  point  becomes  twisted 
on  its  own  axis  several  times,  thus  producing  the  convoluted  form  exhibited 
under  the  microscope. 

According  to  Hanausek  ^  the  greater  the  number  of  twists  in  a  given 
length  of  the  fiber  and  the  greater  the  regularity  of  these  twists,  so  much 
the  greater  is  the  commercial  value  of  the  cotton.  The  correctness  of 
this  statement,  however,  is  disputed  by  Herbig.  For  about  three-fourths 
of  its  length  the  fiber  maintains  a  comparatively  uniform  diameter,  then 
it  gradually  tapers  to  a  point,  where  it  is  perfectly  cylindrical  and  often 
sohd  (Fig.  190). 

In  some  cases  portions  of  a  fiber  may  exhibit  cylindrical  and  apparently 
solid  spaces,  doubtless  caused  by  irregularities  in  the  growth  of  the  cell. 
At  these  places  the  strength  of  the  fiber  is  weakened,  and  will  not  absorb 
solutions  to  the  same  degree  as  the  rest  of  the  fiber.     The  cell-wall  is 

rather  thin  and  the 
lumen  occupies  about 
two-thirds  of  the  entire 
breadth  and  shows  up 
very  prominently  in 
polarised  light.  Be- 
tween its  thickened 
edges  the  fiber  exhib- 
its the  appearance  of 
a  finely  granulated 
surface. 

Fibers  of  dead  cot- 
ton, or    those    which 
have  not  reached  their 
full  maturity,  are  sel- 
dom  twisted    spirally 
and    do   not    have  a 
lumen,  but    are   thin, 
transparent      bands 
(Fig.     185).      Unripe 
cotton    therefore    has 
not    much   value   for 
purposes  of    manufacture,   as  it   contracts  and   curls  up   in  the  warm 
atmosphere  of  the  mill,  and  consequently  yarn  containing  much  unripe 
fiber  depreciates  considerably. 

Denham  points  out  that  the  lumen  of  the  cotton  fiber  contains  in  a 
dead  and.  desiccated  state  the  remains  of  the  protoplasm  and  the  nucleus 
which  were  responsible  for  its  growth.     Wliile  the  luster  of  the  fiber  seems 
1  Microscopy  of  Technical  Products,  p.  61. 


Fig.  200.— Cotton  Fibers, 


Longitudinal  views. 


MICROSCOPY  OF   COTTON   FIBER 


441 


to  be  dependent  on  the  cuticular  surface  and  the  convolutions,  the  color 
is  largely  dependent  on  the  contents  of  the  canal,  which  on  this  account 
have  received  the  label  "  endochrome,"  though  this  should  strictly  be  con- 
fined to  the  coloring  matter  itself.  Curiously  pigmented  forms,  such  as 
"  Khaki,"  "  Blue  Bender,"  and  "  Texas  Wool,"  the  last  a  bright  green, 
occur  from  time  to  time,  as  do  many  less  brightly  colored  "  rogues,"  and 
many  varieties  have  a  strongly  colored  fuzz. 

Microscopically  cotton  fibers  differ  considerably  among  themselves, 
but  in  general  may  be  divided  into  four  classes: 

(a)  Fibers  exhibiting  a  smooth,  straight,  flat  appearance  with  no  suggestion  of 
internal  structure.  These  include  immature  cotton  fibers  and  also  fibers  which  have 
over-ripened.     The  external  wall  of  the  fiber  is  very  thin. 

(b)  Fibers  exhibiting  a  normal  appearance  through  some  portions  of  their  length, 
and  in  other  parts  a  structureless  appearance  as  in  (a).  These  may  be  termed  "kempy  " 
fibers;  the  sohd,  tubular  portion  of  the  fiber  is  particularly  resistant  to  the  absorption 
of  liquids  and  dyestuffs,  and  consequently  remains  uncolored  whUe  the  rest  of  the 
fiber  is  dyed. 

(c)  Straight,  tubular  fibers  exhibiting  a  well-defined  internal  structure  and  a 
transparent  cell-wall  of  varying  thickness.  Fibers  of  this  character  may  often  be 
mistaken  vmder  the  microscope  for  linen,  especially  if  the  cell-wall  is  thick.  The 
fibers     of     Gossypium 

conglomeratum  are  es- 
pecially liable  to  show 
this  form. 

(d)  Normal  struc- 
ture of  twisted,  band- 
like form. 

In  cross-section 
the  immature  fibers 
show  only  a  single 
line  with  no  struc- 
ture (Fig.  201,  A), 
and  but  little  or  no 
indication  of  an  in- 
ternal opening.  The 
mature  fiber  is 
thicker  in  cross- 
section  and  exhibits 
a  central  opening 
(Fig.  201,  5  and  C). 

Haller  ^  in  de- 
scribing the  micro- 


FiG.  201. — Cross-sections  Cotton  Fibers.     (X500.)     A,A,  un- 
ripe fibers;   B,B,  half-ripe  fibers;  C,C,  fully-ripe  fibers. 


scopic    appearance 

of  cotton,  distinguishes  three  parts,  the  cuticle,  the  cell  membrane,  and  the 
1  Zeit.  Farb.  Chem.,  1907,  p.  125. 


442     THE   PHYSICAL  STRUCTURE   AND   PROPERTIES   OF   COTTON 

lumen.  The  cuticle,  consisting  of  "  cutinised  cellulose,"  has  a  finely  grained 
or  fibrous  structure,  is  insoluble  in  ordinary  cellulose  solvents  but  soluble  in 
strong  alkalies,  and  is  resistant  to  boiling  under  pressure  with  lime  or  even 
with  sodium  hydroxide  of  2°  to  8°  Tw,  It  is,  therefore,  so  Haller  considers, 
very  doubtful  whether  the  "  cutin  "  in  the  cuticle  is  a  fat  as  suggested  by 
Wiesner.  The  cell  membrane,  consisting  of  almost  pure  cellulose,  is  more 
or  less  colored,  the  pigment  being  resistant  toward  common  solvents,  but 
destroyed  by  long  contact  with  oxidising  agents.  The  membrane  is 
soluble  in  ammoniacal  copper  hydroxide  solution  {"  cuprammonium  "), 
treatment  with  this  reagent  leaving  the  cuticle  and  inner  skin  hanging  in 
shreds.  The  lumen  contains  dried  protoplasm,  which  extends  also  into 
the  adjacent  layers  of  the  membrane.  The  protein  is  rendered  visible 
by  staining  with  Safranine,  the  hairs  being  steeped  in  a  solution  of  the  dye 
in  dilute  acetic  acid,  and  then  washed  with  water  and  boiling  alcohol, 
when  the  reddened  fiber  has  been  treated  first  with  "  cuprammonium." 
Haller  suggests  that  in  mercerised  cotton  the  cuticle  is  entirely  lacking, 
and  that  in  dyed  unmercerised  cotton  the  color  is  only  absorbed  on  the 
surface,  while  on  mercerisation  penetration  occurs,  this  accounting  for  the 
deeper  colors.  In  a  later  paper  ^  he  concludes  that  the  outer  membrane 
consists  of  two  structural  elements  which  show  little  difference  under  nor- 
mal conditions  but  are  readily  differentiated  when  the  cellulose  is  trans- 
formed into  oxy-  or  hydro-cellulose. 

Levine,^  by  chemical  and  bacteriological  treatment  followed  by  micro- 
scopic examination,  draws  the  conclusion  that  there  are  five  structural 
elements  involved:  (a)  the  outer  layer  or  integument,  which  is  the  encrust- 
ing layer  and  forms  the  cementing  material  of  the  fiber,  being  a  mixture 
of  cutinous,  pectinous,  gummy,  fatty,  and  other  components;  (6)  the  outer 
cellulose  layer,  a  distinct  spiral  comprising  a  limited  number  of  com- 
ponents, perhaps  one  or  two,  and  possibly  consisting  of  impure  cellulose; 
(c)  the  secondary  layer  of  deposits,  made  up  of  components  which  in  no 
case  have  a  spiral  structure  and  are  5  to  10  in  number;  {d)  the  wall  of  the 
lumen,  a  spiral  much  the  same  as  the  outer  layer,  but  differing  in  chemical 
composition;  (e)  the  lumen,  the  substance  of  which  is  structureless  and 
nitrogenous.  The  evidence  on  which  the  conclusions  are  based  is  not 
detailed. 

A  comparative  study  of  the  materials  for  making  cellulose  esters  has 
led  Noyer^  to  suggest  that  the  cuticle  consists  of  oxycellulose,  which  is 
porous,  has  great  osmotic  properties,  and  is  not  acted  upon  by  esterifying 
agents,  but  allows  these  to  penetrate  into  the  fibrils  by  osmosis. 


1  Kolloid  Zeitsch.,  1907,  p.  127. 

"^Science,  1914,  p.  906. 

'  Caoutchouc  &  Guttapercha,  1913,  p.  703. 


PHYSICAL  PROPERTIES;    SPINNING  QUALITIES  443 

10.  Microchemical  Reactions. — The  most  characteristic  of  the  micro- 
chemical  reactions  for  cotton  is  that  with  ammoniacal  copper  solution, 
previously  described.  With  bleached  cotton  the  external  cuticle  may  be 
absent,  and  hence  such  a  fiber  may  not  show  any  distention.  With 
iodine  and  sulfuric  acid  the  cotton  fiber  becomes  blue  in  color,  though 
the  cuticle  remains  colorless.^  Tincture  of  madder  gives  an  orange  color; 
fuchsine  produces  a  red  color  which  is  destroyed  by  the  addition  of  am- 
monia. Flax  does  not  show  this  latter  reaction,  hence  this  serves  as  a 
chemical  means  of  distinguishing  between  cotton  and  linen,  provided  the 
linen  is  unbleached.  Bleached  linen  shows  practically  no  differences  from 
cotton  in  its  chemical  tests.  Anhydrous  stannic  chloride  gives  a  black 
color  with  cotton,  and  sulfuric  acid  dissolves  the  fiber  rapidly. 

Cross-sections  of  the  cotton  fiber  may  be  prepared  by  arranging  a 
number  of  fibers  in  parallel  rows  in  glycerol-gum,  allowing  the  gum  to 
harden  by  drying  and  then  cutting  a  section  with  a  suitable  microtome. 
The  glycerol-gum  is  prepared  from  10  grams  of  gum  arabic,  10  cc.  of 
water,  and  45  to  50  drops  of  glycerol.  The  sections  should  be  examined  in 
water,  and  again  after  treatment  with  iodine-sulfuric  acid  reagent.  This 
causes  the  sections  to  swell  to  broadly  elliptical  or  irregular  forms  without 
altering  the  shape  of  the  lumen,  the  cell-wall  is  colored  blue,  while  the 
cuticle  which  is  distinctly  evident  as  a  delicate  line,  is  colored  yellow,  as 
are  also  the  cell-contents. 

11.  Physical  Properties;  Spinning  Qualities. — The  natural,  spiral- 
like twist  present  in  the  cotton  fiber  causes  the  latter  to  be  especially 
adaptable  to  purposes  of  spinning.  The  spinning  qualities  of  the  cotton 
fiber,  however,  depend  not  onl}^  on  the  nature  and  amount  of  twist  which 
causes  the  individual  fibers  to  lock  themselves  firmly  together,  but  also 
on  the  length  and  fineness  of  staple.  These  three  qualities  in  general  will 
determine  the  character  and  fineness  of  yarn  which  may  be  spun  from  any 
sample  of  cotton.  Sea-island  cotton  lends  itself  to  the  spinning  of  very 
fine  yarns,  being  spun  to  even  300's  (that  is,  300  hanks  of  840  yds.  each 
would  weigh  1  lb.),  and  in  an  experimental  manner  this  cotton  is  said  to 
have  been  spun  as  fine  as  2000's. 

Kuhn  ^  states  that  wild  varieties  of  cotton  show  a  decreased  number 
and  uniformity  of  twists  than  cultivated  species,  and  the  relapse  of  a 
cultivated  variety  into  a  wild  state  is  always  accompanied  by  a  lessened 
development  of  twist  in  the  fiber.     Kuhn  is  of  the  opinion  that  in  the 

^  In  the  raw  cotton  fiber,  however,  the  coloration  is  Hable  to  be  rather  pale  or 
purphsh,  and  on  various  parts  of  the  surface  there  are  to  be  seen  dark  yellow  plates 
or  spots  caused  by  the  encrusting  materials  on  the  raw  fiber.  The  inner  canal  also 
frequently  contains  granular  protoplasmic  substances  that  give  a  dark  yellow  color. 
In  fact  it  has  been  claimed  that  these  characteristics  are  sufficient  to  distinguish 
between  fibers  of  raw  and  bleached  cotton. 

2  Die  Baumwolle,  p.  122. 


444     THE   PHYSICAL  STRUCTURE   AND  PROPERTIES   OF   COTTON 

wild  plant  the  fibrillae  of  which  the  cell- wall  of  the  fiber  is  composed,  tend 
to  assume  a  more  spiral  formation,  which  causes  the  fiber  to  become  more 
rigid  and  less  elastic  and  prevents  the  production  of  twists.  Cultivation 
tends  to  make  the  constituent  fibrillse  assume  a  position  more  parallel 
to  the  axis  of  the  fiber,  which  makes  the  latter  more  elastic  so  that  it 
more  readily  lends  itself  to  the  formation  of  twists. 

In  the  spinning  of  cotton  yarns  two  general  classifications  are  made: 
(a)  carded,  and  (6)  combed  yarns.  Carded  yarns  are  prepared  from  the 
shorter  stapled  varieties  of  cottons,  and,  as  a  rule,  are  only  spun  in  com- 


FiG.  202 —Revolving  Flat  Cotton  Card.     (Whitin  Mch.  Wks.) 


paratively  low  counts  (under  80's).  Combed  yarns  are  made  from  the 
longer  stapled  cottons,  and  for  this  purpose  it  is  necessary  to  comb  out  or 
eliminate  the  shorter  fibers  occurring  in  the  cotton.  This  is  done  by 
means  of  the  cotton  comber  which  has  the  purpose  of  extracting  all  fibers 
having  less  than  a  certain  length,  so  that  the  combed  sliver  consists  princi- 
pally of  the  long  fibers.  The  fibers  in  this  sliver  are  also  much  more 
uniform  in  length  than  those  of  carded  cotton,  and  these  two  conditions 
have  much  influence  on  the  quality  and  appearance  of  the  finished  j'arn, 
making  it  stronger  and  smoother.  In  the  combed  yarn  more  advantage  is 
taken  of  the  strength  of  the  individual  -fiber  itself,  whereas  in  yarns  spun 
from  shorter  staples  and  of  varying  lengths  of  fibers,  the  tensile  strengtli 


TENSILE   STRENGTH 


445 


of  the  yarn  depends  principally  on  the  resistance  to  breaking  offered  by  the 
cohesion  of  the  interlocked  fibers.  This  cohesion  or  clinging  is  due  to  the 
natural  convolutions  or  twists  in  the  fiber  accentuated,  of  course,  by  the 
twisting  of  the  fibers  about  one  another  in  the  spinning  of  the  yarn.  The 
smoothness  of  the  combed  yai'n  is  due  to  the  fact  that  the  fibers  lie  parallel 
to  each  other  and  to  the  direction  of  the  yarn.  In  carded  yarns,  on  the 
contrary,  the  shorter  fibers  lie  in  many  directions  and  manj^  of  the  ends 
of  the  shorter  fibers  protrude  from  the  yarn,  making  it  uneven  and  lumpy. 
It  is  also  necessary  to  give  more  twist  to  carded  yarns  in  order  to  obtain 
the  desired  strength.  The  elimination  of  the  short  fibers  in  combed  yarns 
also  permits  of  much  more  uniformity  in  spinning,  and  this  naturally 


Fig.  203.— Cotton  Comber,  Nasmith  Type.     (Whitin  Mch.  Wks.) 


minimises  the  occurrence  of  thick  and  thin  places  in  the  yarn.  Combed 
"otton,  owing  to  the  action  of  the  needles  in  the  comber,  has  much  greater 
iarallelisation  of  the  fibers,  and  on  this  account  the  yarn  has  much  more 
lister  than  carded  yarn.  There  is  also  much  less  impurity  in  combed 
/arns,  the  comber  cleaning  the  fiber  very  thoroughly. 

12.  Tensile  Strength. — In  its  tensile  strength  cotton  stands  between 
;ilk  and  wool ;  whereas,  in  elasticity,  it  is  considerably  below  either  of  the 
)ther  two  fibers.  The  breaking  strain  of  the  single  fiber  of  cotton  will 
^ary  from  2.5  to  10  grams,  depending  on  the  fineness  of  staple;  the  finer 
he  fiber  the  less  will  be  its  breaking  strain. 

I  The  following  table  shows  the  results  of  experiments  on  the  tensile 
itrength  of  different  varieties  of  cotton: 


446     THE   PHYSICAL   STRUCTURE   AND   PROPERTIES    OF   COTTON 


Cotton. 


Sea-island  (Edisto) . 

Queensland 

Egyptian 

Maranham 

Bengal 

Pernambuco 

New  Orleans 

Upland 

Surat  (Dhollerah) . 
Surat  (Comptah) . . 


Mean  Breaking  Strain. 


Grains. 

Grams. 

83.9 

5.45 

147.6 

9.59 

127.2 

7.26 

107.1 

6.96 

100.6 

6.53 

140.2 

9.11 

147.7 

9.61 

104.5 

6.79 

141.9 

9.22 

163.7 

10,64 

Lecomte  gives  the  following  table  showing  the  breaking  strain  of 
various  cotton  fibers. 

^  ,,  Breaking  Strain. 

Cotton.  ^ 

Grams. 

New  Orleans 9 

Texas 6.6 

Peru  (harsh) 10. 5 

Peru  (long,  silky) 4.1 

Sea-island 8 

Port-au-Prince 9.5 

Haiti 5.1 

Tahiti 4.9 

Egyptian  (brown) 7.6 

Bengal 4 

Tinnevelly 3.2 

The  following  table  exhibits  the  comparative  values  of  the  tensile 
strength  of  different  fibers.  The  "  breaking  length  "  refers  to  a  length 
of  thread  which  will  break  by  reason  of  its  own  weight. 


Breaking  Length 

Tensile  Strength, 

Fiber. 

in 

Kilograms  per 

Kilometers. 

Square  Mm. 

Cotton 

25.0 

37.6 

Wool 

8.3 

10.9 

Raw  silk 

33.0 

44.8 

Flax  fibers 

24.0 
20.0 

35.2 

28.7 

Jute 

Ramie 

20.0 

28.7 

Hemp 

30.0 

45.0 

Manila  hemp 

31.8 

47.7 

Cocoanut  fiber 

17.8 

29.2 

Vegetable  silk 

24.5 

35.9 

TENSILE  STRENGTH 


447 


The  full  tensile  strength  of  the  individual  fiber,  however,  is  not  utilised 
in  the  spun  yarn.  Single  yarns  will  give  only  about  20  percent,  or  one- 
fifth,  of  the  breaking  strain  calculated  from  the  strength  of  the  separate 
fibers;  two-ply  yarns  give  about  25  percent.  Herzfeld  ^  gives  the  following 
table  showing  the  strength  in  grams  of  single  cotton  yarns  of  different 
counts,  the  numbering  of  the  yarns  being  according  to  the  metric  system : 


No. 

Weak. 

Medium. 

Strong. 

Very 

Strong. 

No.  \^ 

leak.    Medium. 

Strong. 

Very 
Strong. 

4 

880 

1000 

1250 

32 

125     170 

200 

250 

6 

670 

920 

1080 

1340 

34 

120     160 

190 

220 

8 

500 

690 

810 

1000 

36 

110     150 

180 

210 

10 

400 

550 

650 

800 

38 

105     140 

170 

200 

12 

330 

460 

540 

660 

40 

100     135 

160 

190 

14 

285 

390 

460 

570 

50 

110 

130 

140 

16 

250 

340 

400 

500 

60 

90 

110 

125 

18 

220 

300 

360 

440 

70 

80 

90 

105 

20 

200 

280 

320 

400 

80 

70 

80 

95 

22 

180 

250 

295 

360 

90 

60 

70 

85 

24 

170 

230 

270 

330 

100 

55 

65 

80 

26 

150 

210 

250 

310 

110 

50 

60 

70 

28 

140 

200 

230 

290 

120 

45 

55 

60 

30 

130 

180 

215 

260 

Monie  also  gives  a  table  showing  the  strength  of  cotton  fibers  after 
manufacture  into  yarn  in  relation  to  those  in  their  natural  conditioru 


Carded  Cotton 


Description  of  Yarn. 


Average 
Number 
of 
Fibers 
in  Cross- 
section 
of  Yarn. 


Test 

Strength 

of 

Each 

Fiber 

in 
Grains. 


Calcu- 
lated 
Strength 
of  Yarn 

in 
Pounds. 


Actual 
Strength 

of  Yarn 

in 
Pounds. 


Percent- 
age of 
Strength 
Utilised. 


32's  twist  American  cotton 

36's  " 

40's  " 

46's  ' 

50's  ' 

60's  ' 

70's  ' 

80's  ' 


'     Egyptian  cotton 

I  ( <  II 

'     brown  Egyptian  cotton . . 


120 
110 
100 
132 
110 
100 
74 
60 


140 
140 
140 
146 
146 
146 
150 
150 


200 
176 
160 
220 
184 
167 
127 
103 


49.5 
40.0 
36.0 
52.0 
46.0 
33.5 
27.5 
23.5 


24.7 
22.7 
22.5 
23.6 
25.0 
20.6 
21.6 
22.8 


Yarns  and  Textile  Fabrics,  p.  95. 


448     THE  PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  COTTON 

Combed  Cotton 


80's  twist  Egyptian  cotton . 
120's 
120's 
143's 
165's 
190's 


Sea-island  cotton. 


90 

120 

100 

25 

55 

120 

66 

18 

50 

120 

68 

15 

40 

120 

55 

13 

45 

100 

55 

13 

38 

100 

43 

10.5 

20.3 
24.2 
22.0 
23.6 
25.4 
24.4 


The  following  table  shows  the  breaking  length  and  corresponding 
elasticity  (elongation  sustained  under  the  breaking  strain)  of  yarns  from 
various  fibers: 


Cotton  yarn 

Ramie  yarn 

Flax  yarn  (wet  spun) .... 
"       "     (dry  spun) .... 

Jute  yarn 

Artificial  silk 

Wood  pulp  yarn  (Silvalin) 


Breaking  Length 
in  Kilometers. 

Elasticity. 

13-14 

3.97 

11-12 

0.8-1.8 

12-20 

1.1-1.8 

11-12 

2.5-3.7 

9.9 

2.0 

12.0 

2.0 

5.5 

6.8 

In  determining  the  breaking  strength  of  cotton  fabrics  or  yarns  atten- 
tion must  be  drawn  to  the  influences  of  varying  amounts  of  moisture  in 
the  material,  and  in  making  comparative  tests  care  should  be  taken 
that  the  samples  are  tested  under  the  same  hygroscopic  conditions. 
Scheurer  ^  gives  the  following  results  showing  the  influence  of  moisture 

on  the  tensile  strength: 

Relative  Strength. 

1 .  Cloth  containing  normal  moisture 100 

2.  Same  cloth  made  perceptibly  damp  with  water 104 

3.  Same  cloth  dried  and  tested  warm 86 

4.  Same  cloth  completely  moistened  with  water 103 

Greenwood  ^  has  made  an  exhaustive  study  on  the  effect  of  certain 
industrial  processes  on  the  strength  of  cotton  fibers  and  yarns.  Cotton 
was  spun  from  selected  Egyptian  cotton  and  samples  of  the  yarn  were 
submitted  to  the  following  tests:  two-ply  (1)  gray,  (2)  gray  mercerised, 
(3)  bleached,  (4)  mercerised  and  bleached,  (5)  gray  gassed,  (6)  gray  gassed 
and  mercerised,  (7)  gassed  and  bleached,  (8)  gassed,  mercerised  and 
bleached,  (9)  mercerised  without  tension.     Also  singles  (1)  gray,  (2)  gray 

1  Bull.  Soc.  Ind.,  Mulh.,  1902. 
^  Jour.  Textile  Institute. 


METHODS   OF   DETERMINING   TENSILE   STRENGTH   OF   FIBERS     449 

gassed,  (3)  scoured,  (4)  bleached,  A  large  number  of  tests  were  made  at 
a  constant  humidity  of  70  percent.  It  was  found  that  the  various  proc- 
esses up  to  and  including  spinning  have  no  detrimental  effect  on  the 
strength  of  the  individual  fibers.  If  the  final  count  is  not  considered,  the 
effect  of  gassing  was  contradictory;  mercerising  strengthened  the  yarn 
in  all  cases,  but  the  strength  of  the  fibers  remained  the  same.  Bleaching 
strengthened  the  yarn  in  nearly  all  cases,  but  weakened  the  fibers.  Each 
of  the  processes  increased  the  breaking  strength  of  the  yarn.  From  this 
study  it  would  appear  that  a  yarn  realises  more  of  the  available  fiber 
strength  than  has  been  previously  assumed.  The  increased  yarn  strength 
is  to  be  attributed  to  the  greater  cohesion  of  the  fibers.  It  is  also  sug- 
gested that  the  increased  strength  of  the  yarn  after  bleaching  is  due  to  the 
removal  of  the  natural  wax  which  tends  to  act  as  a  lubricant. 

13.  Methods  of  Determining  Tensile  Strength  of  Fibers. — There  have 
been  a  number  of  machines  devised  for  the  purpose  of  determining  the 
tensile  strength  and  elasticity  of  fabrics  and  yarns,  and  a  few  instruments 
have  also  been  adapted  for  the  testing  of  single  fibers.  As  the  individual 
fiber,  however,  is  a  very  slender  and  delicate  object,  especially  in  the  case  of 
certain  vegetable  fibers,  the  determination  of  its  physical  factors  is  an 
operation  which  requires  a  delicately  adjusted  apparatus.  In  machines 
which  require  the  taking  on  or  off  of  weights,  the  jar  is  usually  sufficient 
to  break  the  fiber  before  its  true  breaking  strain  is  reached.  The  same 
criticism  is  also  true  for  machines  employing  water  as  a  weight.  A  machine 
devised  by  the  author  has  proved  very  satisfactory  for  determining  the 
tensile  strength  and  elasticity  of  almost  any  fiber,  from  very  fine  and 
delicate  filaments  to  coarse  and  strong  hairs. 

A  diagrammatic  drawing  of  this  machine  is  given  in  Fig.  204.  The 
fiber  to  be  tested  is  clamped  between  the  jaws  at  J,  the  pointer  attached 
to  the  end  of  the  beam  above  the  upper  jaw  being  brought  to  the  zero- 
mark  on  the  scale  S,  while  the  lower  jaw  is  raised  or  lowered  in  its  stand 
until  the  desired  distance  between  the  jaws  is  obtained.  To  obtain 
comparable  results  this  distance  should  always  be  the  same;  and  10  cm., 
in  the  case  of  long  fibers,  or  2  cm.  for  short  fibers,  have  proved  to  be  good 
lengths  of  fiber  to  test.  The  sliding-bar  R  is  moved  forward  by  turning 
the  rod  T,  which  moves  the  rack  and  pinion  at  P,  until  the  graduation 
on  the  wheel  G  is  at  zero  to  the  indicator.  Under  these  conditions  there 
is  no  strain  on  the  fiber.  A  stretching  force  is  then  placed  on  the  fiber 
by  moving  the  bar  R  backward  by  turning  the  rod  T;  the  motion  of  this 
bar  is  made  uniform  and  gradual  until  the  fiber  finally  breaks  under  the 
strain  thus  placed  upon  it.  The  graduation  on  the  wheel  G  will  then 
indicate  in  decigrams  the  breaking  strain  of  the  fiber  being  tested.  The 
elasticity  is  obtained  by  watching  carefully  the  pointer  moving  up  the 
scale  of  millimeters  at  S  until  the  rupture  of  the  fiber  takes  place;   the 


450     THE   PHYSICAL   STRUCTURE   AND   PROPERTIES   OF   COTTON 

distance  this  pointer  moves  represents  the  actual  stretch  of  the  fiber,  and 
if  the  length  of  fiber  taken  between  the  jaws  is  10  cm.,  this  figure  will 
represent  directly  the  percentage  of  elasticity.  If  the  length  of  fiber  taken 
is  only  2  cm.,  to  obtain  the  percentage  of  elasticity  it  is  necessary  to 
multiply  the  amount  of  stretch  in  millimeters  by  five;  and  for  other 
lengths  of  fiber  similar  proportions  will  hold.  The  weight  W  at  the  rear 
end  of  the  beam  can  be  moved  backward  or  forward,  and  is  for  the  purpose 
of  adjusting  the  balance  so  that  there  is  no  strain  at  J  when  the  indicator 
on  G  marks  zero.  The  wheel  G  is  graduated  in  decigrams,  and  this  marks 
the  sensibility  of  the  machine;  the  total  graduations  on  G  running  from 
zero  to  400.    When  fibers  are  tested  having  a  greater  tensile  strength 


Fig.  204. — Fiber- testing  Maching. 


than  400  decigrams  a  fixed  additional  weight  of  10,  25,  50,  etc.,  grams  may 
be  hung  from  W,  and  this  must  be  added  to  the  reading  on  the  wheel 
when  the  fiber  breaks.  If  the  elasticity  of  the  fiber  is  so  great  as  to  carry 
the  pointer  beyond  the  limits  of  the  scale  at  S,  a  shorter  length  of  fiber 
must  be  tested.  A  fair  average  of  breaking  strain  and  elasticity  may  be 
obtained  for  any  quality  of  fiber  by  testing  about  ten  separate  fibers  and 
taking  a  mean  of  the  total  tests.  If  the  quality  of  the  fibers,  however,  in 
a  sample  does  not  run  very  uniform,  it  is  best  to  increase  the  number  of 
tests  to  twenty-five  or  even  fifty  in  order  that  a  satisfactory  average  may 
be  obtained. 

The  Bureau  of  Plant  Industry  at  Washington  has  made  quite 
extensive  tests  on  the  tensile  strength  of  cotton  fibers  by  the  use  of  a 
machine  of  the  same  character  as  that  above  described.  In  making  the 
tests  the  single  fiber  is  picked  up  with  a  pair  of  forceps  and  placed  in  the 


i 


METHODS    OF    DETERMINING    TENSILE    STRENGTH    OF    FIBERS     451 

jaws  of  the  machine,  the  rounded  faces  of  which,  pressed  together  with 
springs,  hold  the  fiber  firmly  but  do  not  cut  it.  The  weight  is  then  added 
by  turning  the  thumbscrew  with  a  uniform  motion,  and  the  breaking 
strain  is  read  on  the  dial  in  tV  gram;  twenty  fibers  were  broken,  one  at  a 
time,  and  the  average  determined  as  the  breaking  strength  of  the  sample. 
While  there  is  much  variation  in  every  sample,  it  has  been  found  by 
numerous  trials  that  the  average  breaking  strain  of  twenty  fibers  is  approx- 
imately the  same  as  that  for  a  larger  number  of  fibers.  This  is  especially 
true  of  seed  cotton,  where  it  is  possible  to  take  one  fiber  from  each  of 
twenty  samples.  Furthermore  it  was  found  that  the  fibers  taken  from 
midway  on  the  side  of  the  seed  are  more  uniform  than  those  at  either  end ; 
those  at  the  pointed  end  are  most  variable.  The  results  from  a  large 
number  of  tests  from  nearly  all  of  the  prominent  varieties  of  the  seven 
different  groups  of  American  Upland  cotton,  and  also  Sea-island  and 
Egyptian  cottons,  are  given  in  the  following  table: 

TENSILE  STRENGTH  OF  COTTON  FIBERS 


Variety  of  Cotton. 


American  Upland: 

Big-boll  stormproof  group .  .  . 

Big-boll  group 

Cluster  group 

Semicluster  group 

Peterkin  group 

Early  group 

Long  staple  group 

Sea-island 

Egyptian : 

From  Arizona  and  California 


123 


High, 

Low, 

Average, 

Grains. 

Grains. 

Grains. 

139 

80 

103 

179 

71 

102 

119 

79 

92 

109 

72 

90 

92 

77 

88 

106 

80 

87 

86 

54 

73 

117 

72 

95 

86 


103 


I 


The  highest  and  lowest  figures  given  in  the  foregoing  table  are  the 
averages  for  twenty  fibers,  not  the  highest  and  lowest  breaking  strain  of 
single  fibers.  The  tensile  strength  of  single  fibers  of  American  Upland 
cotton  is  generally  in  inverse  ratio  to  their  length,  though  the  longer  staples 
make  stronger  yarns.  The  strength  is  in  more  direct  ratio  to  the  diameter. 
The  accurate  measurement  of  the  diameters  of  the  twisted,  ribbonlike 
cotton  fibers  presents  such  difficulties  and  requires  so  much  time  that 
it  is  not  included  in  all  tests. 

A  series  of  tests  has  also  been  made  to  determine  the  pull  necessary 
to  detach  the  fiber  from  the  seed.  In  American  Upland  varieties  this 
ranges  from  29.0  to  35.5  grains,  and  in  Sea-island  from  27.0  to  30.1  grains. 


452     THE   PHYSICAL  STRUCTURE   AND   PROPERTIES  OF   COTTON 


M 


^Hv 


Barrett  {Jour.  Textile  Institute,  1922)  describes  an  apparatus  and 
method  for  the  testing  of  single  fibers  for  tensile  strength  and  elasticity, 
the  basis  of  which  is  a  small  Oertling  balance.  The  pans  are  removed  and 
replaced  by:  (a)  On  the  right — a  bundle  of  magnetised  steel  piano  wires, 
hung  vertically,  with  half  its  length  inside  a  solenoid  of  covered  copper 
wire  through  which  an  electric  current  can  be  sent,  and  accurately  meas- 
ured by  means  of  a  sensitive  ammeter;  {h)  on  the  left — a. small  weight,  in 
order  to  counterbalance  the  magnet  on  the  right.  An  auxiliary  knife 
edge  E  (Fig.  205)  is  constructed,  and  rigidly 
clamped  about  half-way  along  the  left  arm  of 
the  balance.  Suspended  from  this  edge,  but 
easily  removable,  is  a  special  clamp,  FN  A,  to 
hold  the  end  A  of  the  fiber  to  be  tested.  The 
other  end,  B,  of  the  fiber  AB  can  be  clipped 
vertically  below  this  in  another  adjustable  clamp 
BC,  which  is  attached  firmly  at  C  to  the  central 
pillar  of  the  balance.  The  fiber  AB — usually  of 
length  13.5  mm. — is  mounted  by  means  of  bicycle 
cement  in  small  double  paper  squares. 

The  fiber  is  first    inserted   at    A,    the   nut    A^ 
pushed  upward    into   position  to    grip    the    paper 
square,  and  the  clamp  FNA   hung  on  the  knife 
edge  E.      The  adjustable  clamp  B  of  the  attach- 
ment BC  is  moved  into  position   vertically  below 
A,  and  the  end  B   then   secured   firmly   by  means 
of   the   screw  D.     The   balance    can    then    be    put    in    adjustment    by 
lowering  the  beam  supports,  so   that  the  smallest   possible  strain  is  put 
on  the  fiber. 

The   results   of   tests   on  this  machine  are   shown  in  the  following 
table : 


Fig.  205.  —  Barrett's 
Apparatus  for  Test- 
ing Single  Fibers. 


Fibers. 


Scoured  Egyptian  sliver 

Ditto,  mercerised  without  tension. 

Wool  (merino  top) 

Silk 

Artificial  silk  (viscose) 

Linen  fibers  from  aeroplane  fabric, 
Bog  cotton 


Breaking 

Extension  as 

Strength, 

Percent  of  Origi- 

Grams. 

nal  Length. 

7.2 

7.4 

6.7 

12.2 

7.S5 

39.0 

4.01 

18.7 

10.8 

14.5 

19.5 

5.1 

4.7 

2.4 

TESTING  TENSILE  STRENGTH  OF  YARNS  AND  FABRICS      453 

(a)  Elasticity  of  Mercerised  Cotton  Fiber. — In  a  particular  experiment,  a 
pull  of  10.2  grams  produced  an  elongation  of  0.0552  cm.  in  a  fiber  of  length 
1.35  cm.;   sectional  area  was  approximately  0.000003  sq.  cm. 

10.2X981 

T-,,    ^.  .,  Stress  per  unit  area  .000003 

Elasticity  ^  - 


Elongation  per  unit  length         .  0552 
=  0.8X1011  c.g.s.  units. 


1.35 


Elasticity  of  quartz  fiber  is  5Xl0ii  c.g.s.  units  and  of  cast  iron 
about  12X1011. 

(h)  Tensile  Strength  of  Cotton  Fiber. — A  fiber  of  0.000003  sq.  cm.  sec- 
tional area  broke  with  a  load  of  7.2  grams. 

7  2X981 
Tensile  Strength  =    "  /^r^p^p^p^o  =  2 . 4  X 10^  dynes  per  square  centimeter. 

(Tensile  strength  of  steel  is  15X10^  dynes  per  square  centimeter.) 

14.  Testing  Tensile  Strength  of  Yarns  and  Fabrics. — As  the  deter- 
mination of  the  strength  of  individual  fibers  is  a  rather  painstaking  and 
tedious  operation,  it  is  more  customary  to  test  the  breaking  strength  of 
yarns  or  fabrics.  This  is  sometimes  even  better  for  commercial  work 
than  the  testing  of  the  single  fibers,  as  it  is  really  the  strength  of  the 
manufactured  yarn  or  cloth  that  is  desired  for  most  practical  purposes. 
The  strength  and  elasticity  of  yarns  is  readily  obtained  on  special  testing 
machines  such  as  those  shown  in  Figs.  206,  207,  and  208.  Cloth-testing 
machines  are  also  constructed  in  much  the  same  manner.  Another 
method  of  determining  the  strength  of  cloth  is  to  obtain  the  "  bursting 
strain  "  by  means  of  the  well-known  Mullen  tester  used  so  much  for 
testing  the  strength  of  paper. 

A  yarn-testing  apparatus  that  automatically  records  the  strength  and 
elasticity  is  shown  in  Figs.  209  and  210.  It  is  known  as  the  Zeidlitz 
apparatus  and  operates  as  follows:  A,  yarn  to  be  tested  as  it  comes  off 
the  cop  and  passes  over  two  half-round  pegs  at  a  to  take  up  slack. 
B,  string  passing  over  disk,  S,  and  ends  fastened  to  balance  weights, 
G  and  M.  C,  fixture  for  fastening  one  end  of  yarn.  D,  a  clamp  attached 
to  M  for  fastening  the  other  end  of  the  yarn.  E,  lever  with  pivot  point 
or  fulcrum  between  the  ends.  F,  a  small  weight  attached  to  string  which 
passes  over  a  pulley,  around  top  of  drum,  P,  over  pulley  and  is  attached 
to  H.  The  weight  of  F  is  equal  to  the  weight  of  J^  in  water.  G,  weight 
attached  to  string,  B,  and  equal  to  weight  of  M  when  empty.     H,  weight 


454     THE   PHYSICAL  STRUCTURE   AND   PROPERTIES   OF  COTTON 


floating  in  water,  so  that  its  weight  floating  is  equal  to  F.  M,  a  graduated 
glass  flask,  suspended  by  a  cord,  B,  by  an  attachment  at  the  top  of  M. 
To  this  attachment,  clamp,  D,  is  fastened,  so  that  when  M  descends, 
D  also  goes  down,  putting  tension  on  yarn.     A^,  a  vessel  containing  water, 

in  which  H  is  float- 
ing. To  the  top  of  N, 
a  pulley  is  attached, 
acting  as  a  guide  for 
a  string  attached  to 
F.  P,  drum  which 
turns  on  a  vertical 
axis  by  the  pull  of  the 
string  connecting  F 
and  H.  Upon  this 
drum  is  a  clamp  which 
will  hold  a  piece  of 
paper  wrapped  around 
the  drum.  This  paper 
is  divided  into  coor- 
dinates, vertical  and 
horizontal  lines  at 
regular  intervals.  The 
horizontal  lines  indi- 
cate units  and  per- 
cent of  stretch  or 
elasticity;  vertical 
lines  indicate  units  of 
strength.  As  soon  as 
the  yarn  breaks,  0  no 
longer  stretches  the 
yarn,  C  is  not  pulled 
down,  V  is  closed, 
thus  instantly  shut- 
ting off  the  water  go- 
ing into  M,  and  W, 
acting  as  a  ratchet, 
Fig.  206. — Combined  Power  Yarn  and  Cloth  Tester.  (Scott.)  engages  the  teeth  stop, 

S.  Thus  the  amount 
of  water  in  M  records  the  breaking  strength  of  the  yarn;  S  records  the 
stretch  of  yarn;  and  the  chart  on  P  keeps  a  record  of  the  stretch  and 
strength  of  the  yarn  from  zero  to  the  breaking  load. 

In  the  testing  of  cotton  goods  for  tensile  strength,  it  is  recognised 
that  the  only  accurate  way  is  to  dry  out  all  the  moisture  before  the  test. 


TESTING   TENSILE   STRENGTH  OF   YARNS   AND   FABRICS       455 

The  moisture  plays  a  leading  part  in  the  strength  of  the  goods,  since  one 

i  percent  of  moisture  regain  adds  about  6^  percent  of  strength  to  the  goods. 

It  is  quite  essential,  therefore,  that  the  breaking  strength  as  shown  by 

tests  should  be  readjusted  to  the  same  moisture  content.     The  following 


Fig.  207.  Fig.  208. 

Fig.  207. — Skein  Yarn  Tester  with  Automatic  Recorder.     (Scott.) 

Fig.  208.— Single  Strand  Yarn  Tester. 

formula  recommended  by  the  Textile  Committee  of  the  American  Society 
of  Testing  Materials  may  be  used  in  making  the  calculation: 

Tensile   strength   corrected   to  1  _  Machine  reading  XI 39 
6.5  percent  moisture  regain  J       1 00  +  (6  X actual  regain) 


456     THE  PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  COTTON 


E,    iC 


Fig.  209.-Diagram  of  Zeidlitz  Tester.        Fig.  210.-Yarn  Tester.     (Zeidlitz.) 


TESTING  TENSILE  STRENGTH  OF  YARNS  AND  FABRICS      457 


Scheurer  ^  made  some  interesting  tests  on  cotton  fabrics  with  regard 
to  the  effect  of  various  treatments  on  the  strength,  the  results  of  which 
are  given  in  the  following  table: 

Relative  Strength. 

1 .  Bleached  fabric  (standard) 100 

2.  Hung  for  one  month  in  aging  room 98 

3.  Hung  for  one  month  in  drying  chamber 96 

4.  Hung  for  one  month  in  wool-drier 96 

5.  Exposed  for  one  month  to  air  and  rain 98 

6.  Passed  twenty  times  through  washer 96 

7.  Soaped  six  hours  at  212°  F.  (2  grams  soap  per  liter) .  . .    101 

8.  Soaped  twelve  hours  as  above 99 

9.  Passed  ten  times  around  calendering  roll 80 

10.  Treated  as  (9)  and  washed 78 

11.  Damped  and  dried  on  cylinder  twenty  times 97 

12.  Boiled  thirty  minutes  in  soda  ash  (10  grams  per  liter) .  .    100 

13.  Treated  with  5  percent  solution  of  chloride  of  hme  of 

10°  Tw.,  dried  on  cylinder  and  treated  as  (12) 100 

14.  Treated  as  (13)  twice 98 

A  form  of  tester  especially  designed  for  the  testing  of  fabrics  is  that 
shown  in  Fig.  211.  This  apparatus  gives  the  tensile  strength  of  the 
material  in  pounds  per  linear  inch, 
and  is  operated  hydraulically.  The 
cylinder  is  filled  with  a  liquid  which  is 
compressed  by  a  solid  metal  plunger, 
which  fits  the  cylinder  with  a  very 
accurately  ground  and  lapped  fit,  and 
has  no  packings  to  wear  out  or  get  out 
of  order.  This  plunger  is  attached 
to  the  upper  or  stationaiy  clamp  by 
means  of  a  stirrup  which  brings  the 
pull  in  a  straight  vertical  line  with- 
out cramping  and  without  side  pull. 
The  lower  or  moving  clamp  is  attached 
to  a  vertical  screw  which  is  operated 
by  means  of  a  handwheel  on  the 
side  of  the  machine.  The  pressure  is 
indicated  on  a  specially  made  standard 
gauge  which  is  acted  on  by  hydraulic 
pressure  from  the  cylinder.  The 
readings  are  given  in  pounds  per  inch 
breaking  strength  of  a  strip  of  cloth  or 
other  material.     The  material  to  be 

tested  is  therefore  cut  into  strips  1  in.  wide.     Removable  and  interchange- 

^Bull.  Soc.  Ind.  Mlh.,  1902. 


Perkins  Tester  for  Strength  of 
Fabrics. 


458     THE   PHYSICAL  STRUCTURE   AND   PROPERTIES  OF  COTTON 

able  stop-gauges  are  provided  which  automatically  separate  the  clamp 
jaws  1  in.,  2  ins.,  or  4  ins.  apart,  as  desired,  so  that  strips  of  these  lengths 
may  be  tested  easily.  The  material  is  inserted  and  clamped  uniformly 
and  without  side  cramping  by  means  of  a  device  whereby  the  clamp  jaws 
are  held  rigid  during  the  insertion  of  the  piece  to  be  tested.  As  soon  as  the 
test  is  begun,  the  clamp  jaws  are  freed  so  that  they  are  on  a  swivel,  and 
the  strain  of  the  material  is  thus  taken  up  uniformly.  When  the  hand- 
wheel  has  tin-ned,  the  piece  of  cloth  under  test  is  subjected  to  a  direct  pull. 
This  operates  on  the  fluid  in  the  cylinder,  which  simultaneously  acts  on 


Fig.  212.— Testing  Machine  for  Fabrics.     (Scott.) 


the  standard  pressure  gauge.  The  pointer  on  the  gauge  stops  automatically 
as  soon  as  the  material  breaks,  and  thus  accurately  indicates  the  tensile 
strength  of  the  material  to  the  exact  breaking  point  in  pounds  per  inch, 
the  pointer  remaining  stationary  until  it  is  released  by  pressing  a  button 
on  the  side  of  the  gauge. 

For  determining  the  degree  of  uniformity  of  the  tensile  strength  of 
yarns  Lerch  ^  recommends  the  following  method:   (1)  Find  the  arithmetic 

1  Monatschr.  Text.  Ind.,  1922,  p.  187. 


TESTING  TENSILE   STRENGTH  OF   YARNS  AND   FABRICS       459 

mean  of  the  results,  the  sub-mean  and  the  super-mean;  (2)  determine 
the  "  quahty  "  mean  by  adding  the  sub-mean  and  the  super-mean  and 
dividing  by  2;  (3)  subtract  the  quahty  mean  from  the  super-mean  and 
multiply  the  remainder  by  the  ratio  of  the  greatest  value  to  the  lowest  value 
and  by  100.  For  example,  if  the  super-mean  is  280  and  the  sub-mean  220, 
the  greatest  value  is  285  and  the  least  value  is  215,  then  the  quality  mean 
is  250,  and  the  degree  of  uniformity  is  (280-250)X  100X285/215=  15.6 
percent.  If  this  value  is  less  than  10  percent,  the  yarn  may  be  considered 
as  very  even,  and  if  above  20  percent  as  uneven. 

In  the  Scott  tester  for  textile  fabrics  an  iron  base  supporting  two  side 
frames  contains  the  entire  mechanism,  which  is  designed  to  be  placed  upon 
a  bench  or  desk.  Two  bearings  mounted  upon  the  top  of  the  side  frames 
carry  a  walking  beam  or  inclinable  plane  upon  which  rest  two  round 
weights  connected  together  by  a  ball-bearing  carriage.  Fastened  to  a 
cross  bar  in  this  carriage  is  a  chain  which  passes  over  a  pulley  and,  dropping 
in  a  vertical  direction,  supports  the  upper  or  moving  clamp.  The  lower 
clamp  is  attached  rigidly  to  the  frame  but  is  mounted  upon  a  screw  and 
is  adjustable  for  different  lengths  of  specimens.  The  inclined  plane  is 
operated  by  sliding  cross  heads  on  either  side,  which  in  turn  are  lowered 
by  means  of  a  vertical  screw  upon  which  a  worm  gear  acting  as  a  nut 
revolves.  The  worm  driving  this  gear  is  operated  by  a  train  of  change 
gears  driven  from  the  mechanism  below.  These  change  gears  permit 
of  regulating  the  speed  of  the  screw  and  in  turn  the  inclination  of  the 
beam,  and  thus  determine  the  rate  of  load  applied  to  the  specimen.  The 
driving  mechanism  is  operated  by  a  belt  from  a  small  motor  held  within 
the  main  frames.  Two  clutches,  independently  operated,  control  the  drive 
dm-ing  the  test  and  provide  a  quick  speed  return.  Automatic  stops  make 
the  machine  automatic  and  prevent  damage  to  the  machine  from  neglect 
of  the  operator.  When  the  specimen  to  be  tested  has  been  placed  in  the 
clamps  the  machine  is  started  by  means  of  a  small  lever  at  the  front. 
The  operator  may  stop  the  machine  at  the  instant  the  break  occurs; 
the  strength  test  will  then  be  registered  upon  a  dial,  and  the  stretch  or 
elasticity  upon  the  scale  in  front  of  the  recorder.  If  desired,  the  machine 
may  be  allowed  to  operate  automatically,  the  graph  developed  by  the 
recording  instrument  giving  both  strength  and  stretch  records.  The 
chart  is  square  ruled  and  evenly  spaced,  the  vertical  lines  denoting  strength 
and  the  horizontal  lines  the  stretch.  As  the  test  progresses  the  chart  moves 
horizontally  from  right  to  left  while  the  pen,  supported  from  the  rider 
on  the  scale,  moves  upward  as  the  specimen  elongates.  These  two  move- 
ments produce  a  diagonal  line  upon  the  chart  showing  the  exact  progress 
of  the  test  from  the  start  to  the  break.  One  special  feature  of  this  recorder 
is  the  fact  that  its  operation  in  no  way  interposes  friction  to  be  overcome 
by  pull  on  the  specimen  or  in  any  way  influences  the  test. 


460     THE   PHYSICAL  STRUCTURE   AND   PROPERTIES   OF  COTTON 

15.  Hygroscopic  Quality. — Cotton  is  less  hygroscopic  than  either  wool 
or  silk;  under  normal  conditions  it  will  contain  from  5  to  8  percent  of 
hygroscopic  moisture,  though  in  a  very  moist  atmosphere  this  may  be 
considerably  increased. 

Kuhn  ^  states  that  a  portion  of  this  moisture  must  be  regarded  as  a 
constituent  part  of  the  fiber.  This  water  of  constitution,  he  states, 
amounts  to  about  2  percent.  It  can  be  expelled  at  over  105°  C,  and  the 
fiber  then  becomes  harsh  and  brittle,  and  loses  its  elasticity.  This  state- 
ment concerning  water  of  constitution,  however,  demands  further  investi- 
gation before  it  can  be  unreservedly  accepted  as  a  fact. 

The  following  table  shows  the  results  of  a  series  of  tests  to  determine 
the  hygroscopic  moisture  in  various  grades  of  cotton: 


Percent  of  Moisture. 

Graae. 

Maximum. 

Minimum. 

Average. 

r  Texas 

14.8 

6.9 

9.2 

Orleans 

9.9 

7.8 

9.7 

Memphis 

9,8 

7.1 

9.4 

North  American..  1 

Sea-island 

9.9 

7.4 

9.6 

Savannah 

16.2 

10.7 

13.8 

Norfolk 

10.3 

8.4 

9.4 

t  Florida 

8.9 

7.2 

8.7 

Maceio 

8.1 

8.3 

11.8 

7.3 

8.1 

South  American . .  < 

Paraiba 

Brazil 

8.3 
9.5 

Peru 

9.8 
9.5 

7.5 
6.8 

9.1 

r  Ashmouni 

8.4 

Egyptian 

Gallini 

10.8 

7.1 

9.3 

k  Brown 

8.7 

7.8 

8.5 

Surat 

7.7 

6.2 

7.5 

Indian 

Dhollerah 

Bengal 

8.1 
8.2 

6.4 

7.0 

8.2 

Tinnevelly 

7.9 

7.9 

Beltzer  -  states  that  Indian  cottons  under  the  same  atmospheric 
conditions  absorb  about  1.5  percent  more  of  moisture  than  American 
cottons,  though  this  difference  is  only  manifested  within  certain  limits  as  to 
the  saturation  of  the  air  with  water  vapor;  when  the  relative  humidity  is 
50  percent  the  difference  in  the  amount  absorbed  is  only  1  percent.  Egyp- 
1  Die  Baumwolle,  p.  131.  ^  Les  Matieres  Cellulosiques. 


HYGROSCOPIC  QUALITY  461 

tian  cotton  is  said  to  occupy  an  intermediate  position  between  Indian  and 
American  cottons.  In  the  absence  of  definite  data  in  this  respect,  however, 
the  present  author  is  inchned  to  question  the  conclusions  of  Beltzer. 

The  hygroscopic  quahty  of  cotton  (and,  in  fact,  of  any  other  vegetable 
fiber  as  well)  has  much  to  do  with  its  proper  condition  during  the  various 
processes  of  spinning  and  finishing.  It  also  has  an  influence  on  the  com- 
mercial valuation  of  the  raw  material,  as  the  amount  of  hygroscopic 
moisture  varies  with  atmospheric  conditions,  and  it  is  important  to  have 
a  normal  standard  of  reference.  Its  influence  on  spinning  is  even  greater, 
and  proper  conditions  of  atmospheric  moisture  must  be  maintained  in  the 
spinning-room  in  order  to  achieve  the  best  results.  The  spinning  properties 
of  raw  cotton,  however,  are  also  affected  by  other  substances  associated 
with  the  cellulose  of  the  fiber,  but  it  is  without  question  that  the  physical 
condition  of  cotton  is  largely  influenced  by  its  content  of  hygroscopic 
moisture,  and  this  should  be  delicately  adjusted  by  the  spinner  to  meet 
the  conditions  of  his  work.  The  mechanical  treatment  of  woven  textile 
materials  in  finishing  processes,  such  as  mangling,  beetling,  calendering,  etc., 
is  also  dependent  for  good  results  to  quite  an  extent  on  the  hygroscopic 
condition  of  the  fiber,  hence  the  amount  of  moisture  present  during  the 
finishing  operations,  together  with  the  method  and  degree  of  drying,  should 
be  carefully  studied. 

In  testing  the  influence  of  moisture  on  the  strength  of  cotton  material, 
the  Industrial  Society  of  Mulhouse  reports  as  follows: 

Normal  strength  of  cloth 100 

Saturated  with  moisture 104 

Dried  on  hot  cyHnder 86 

Again  dampened 103 

It  would  appear  from  these  results  that  the  alternate  moistening  and  hot 
drying  of  cotton  caused  little  or  no  deterioration  in  its  strength. 

L.  Pinagel  has  shown  that  bleached  cotton  on  the  average  will  absorb 
somewhat  less  hygroscopic  moisture  than  unbleached  cotton.     Yarn  spun 

*  from  different  grades  of  cotton  in  the  bleached  and  the  unbleached  condition 
were  dried  in  a  conditioning  apparatus  and  the  dry  weight  noted.     These 

!  yarns  were  then  hung  in  the  same  room  and  the  weight  of  each  skein 
at  the  end  of  sixty  hours  was  also  noted.  It  was  found  in  almost  every 
case  that  the  bleached  yarn  took  up  less  moisture  than  the  unbleached. 
Too  much  confidence,  however,  must  not  be  placed  in  these  results,  as 
the  difference  between  the  bleached  and  unbleached  cotton  was  quite 
small  and  was  often  less  than  the  differences  between  the  different  kinds 
of  cotton  used. 

The  amount  of  "  regain  "  allowed  in  the  conditioning  of  cotton  on  the 
continent  of  Europe  is  8h  percent.  The  following  table  by  Hartshorne 
gives  the  "  regain  "  of  cotton  for  various  temperatures  and  humidities: 


462     THE   PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  COTTON 


TABLE  OF  REGAIN   FOR  COTTON  AT  VARIOUS  TEMPERATURES  AND 
PERCENTAGES  OF  HUMIDITY 


Degrees  Fahrenheit. 

Percentage 

Humidity. 

50 

60 

70 

80 

90 

100 

40 

5.90 

5.79 

5.65 

5.47 

5.25 

5.05 

50 

6.89 

6.78 

6.63 

6.45 

6.18 

5.86 

60 

8.00 

7.87 

7.69 

7.44 

7.13 

6.80 

70 

9.14 

9.00 

8.79 

8.58 

8.32 

8.05 

SO 

10.58 

10.42 

10.23 

9.95 

9.70 

9.60 

90 

12.28 

12.10 

11.85 

11.56 

11.43 

11.85 

100 

14.12 

14.00 

13.80 

13.65 

13.70 

14.50 

The  temperature  and  percentage  of  humidity  suitable  for  various  depart- 
ments of  a  cotton  mill  vary  with  the  nature  of  the  process  and  the  fineness 
of  the  yarn.  The  finer  the  yarn  the  higher  should  be  the  humidity. 
The  following  table  represents  the  general  practice: 


Humidity, 
Percent. 

Temperature, 
Degrees  F. 

Card-room 

Spinning-room 

60-65 
60-75 
75-80 

70-75 
75-80 

Weaving  shed 

70-75 

Thomson  has  pointed  out  the  effect  of  moisture  on  the  strength  of 
cotton  yarn  in  finishing.     He  gives  the  following  figures: 

Moisture  in  Yarn,  Breaking 

Percent.  Strain. 

2.89  (dry) 39.9 

8.93  (usual) 64.0 

17.36  (moist) 69.2 

Other  investigators  have  substantiated  these  results.  The  increase 
in  elasticity  of  moist  yarn  over  dry  yarn  is  about  25  percent,  while  the 
increase  in  strength  is  about  10  percent. 

Cotton  may  combine  with  water  in  two  forms:  (1)  as  hydroscopic 
moisture  and  (2)  as  water  of  hydration.  The  hygroscopic  moisture  is 
that  absorbed  from  moist  air,  and  varies  in  quantity  from  8  to  12  percent, 
depending  on  the  temperature  and  humidity  of  the  air.  This  water  is 
completely  eliminated  by  heating  the  cotton  to  220°  F.,  and  the  cotton 
may  then   be  termed   "  desiccated."     The  water  of  hydration  is  only 


HYGROSCOPIC  QUALITY  463 

separated  at  a  higher  temperature,  320°  to  350°  F.  being  necessary.  At 
these  temperatures  a  further  loss  in  weight  of  1  to  3  percent  is  obtained. 
The  water  of  hydration  may  also  be  estimated  by  first  desiccating  the 
cellulose  at  220°  F.,  then  boiling  in  toluene  and  distilling.  Cotton  contain- 
ing water  of  hydration  is  known  as  cellulose  hydrate  or  hydracellulose. 
The  limit  of  the  hydration  in  cotton  may  be  considered  as  corresponding  to 
mercerised  cotton,  Ci2H2oOio-H20  (see  Cellulose  Hydrate).  These 
statements,  however,  need  further  experimental  data  to  confirm  their 
accuracy. 

When  cotton  is  purified  from  its  adhering  waxy  and  fatty  matters, 
it  becomes  remarkable  absorbent.  This  quahty  is  explained  on  the 
supposition  that  the  ripe  cotton  fiber  is  made  up  of  a  series  of  tissues  of 
cellulose,  separated  from  each  other  by  intercellar  matter,  in  this  way 
forming  a  series  of  capillary  surfaces  which  are  capable  of  exerting  con- 
siderable capillary  force  upon  any  liquid  in  which  the  fiber  may  be  im- 
mersed. Dry  cotton  also  appears  to  be  remarkably  absorptive  of  gases; 
it  is  said  that  the  fiber  can  absorb  115  times  its  volume  of  ammonia  at  the 
ordinary  atmospheric  pressure. 

When  properly  prepared,  absorbent  cotton  should  absorb  18  times 
its  own  weight  of  water.^  On  account  of  the  great  absorbency  of  purified 
cotton  it  is  very  extensively  used  in  the  preparation  of  surgical  cotton  and 
gauze  for  the  packing  of  wounds  and  other  uses  in  medical  practice  and 
surgery.  For  this  purpose  the  cotton  must  be  very  thoroughly  boiled  out 
and  bleached  and  subsequently  medicated  if  so  desired. 

The  following  accurate  method  of  determining  the  amount  of  hygro- 
scopic water  in  cotton  (or  other  cellulose  fiber)  has  been  suggested  by 
C.  Schwalbe.  About  3  grams  of  the  material  is  boiled  with  300-500  cc. 
of  pure  toluene  which  has  a  boiling-point  of  about  230°  F.  The  water  is 
I  collected  by  distillation  in  a  graduated  tube  and  from  a  determination  of 
j  its  volume  or  by  weighing,  the  percentage  of  moisture  may  be  calculated. 
This  method  is  applicable  to  the  determination  of  moisture  in  mercerised 
cotton  and  hydrated  celluloses  (artificial  silk).  The  following  gives  the 
amount  of  moisture  as  determined  in  this  manner  with  different  materials : 

I  Percent. 

Paper  made  from  cotton 6.5 

Vegetable  silk 6.7 

Mercerised  cotton 9 .  25 

woodpulp 10.25 

i|  Viscose  silk 11 .  25 

I 

'  The  cotton  stock  employed  for  making  absorbent  cotton  and  surgical  gauze  is 

obtained  from  linters,  card  strips,  card  fly,  and  comber  waste,  the  last-named  giving 

:   the  best  grades.     Mill  sweepings  cannot  be  used  for  making  surgical  cotton  as  they 

'  cannot  be  bleached  to  a  satisfactory  white  color.     The  mill  sweepings  are  generally 

'   employed  for  the  making  of  guncotton  and  low-quaUty  wadding  for  clothing. 


464     THE  PHYSICAL  STRUCTURE  AND   PROPERTIES  OF  COTTON 

Cotton  which  has  been  deprived  of  its  hygroscopic  moisture  by  drying 
in  an  oven  at  212°  to  220°  F.  by  the  usual  method,  easily  regains  its 
original  amount  of  moisture  after  ten  to  twelve  hours"  exposure  to  the  air. 
When  the  moisture  has  been  removed  by  boiling  toluene,  however,  the 
regain  in  moisture  is  somewhat  less,  on  accomit  of  the  impregnation  of 
the  fibers.  The  method  of  washing  cotton  with  alcohol  before  drying  is 
objectionable,  owing  to  the  fact  that  cellulose  obstinately  retains  alcohol 
which  apparently  cannot  be  removed  by  heat.  When  the  drying  operation 
is  conducted  at  too  high  a  temperature  the  regain  of  moisture  is  also  less, 
so  that  the  normal  region  of  moisture  may  be  taken  as  the  exact  measure 
of  the  hygroscopic  moisture,  without  the  elimination  of  the  water  of 
hydration.  Schwalbe  found  that  the  toluene  method  only  eliminated  the 
hygroscopic  moisture  present  and  did  not  affect  the  ''  water  of  hydration." 

The  difference  in  the  amounts  of  hygroscopic  moisture  absorbed  by 
cotton   subjected  to  various  treatments  is  given  by  Higgins  ^  as  follows: 

Percent. 

Ordinary  cotton,  unbleached 6 .  52 

bleached 6.25 

Mercerised  without  tension,  unbleached 9 .  33 

bleached 9.12 

' '  with  tension,  unbleached 8 .  28 

bleached 8.05 

The  moisture  content  was  determined  after  exposure  to  the  air  for  one 
week.  It  is  interesting  to  note  that  bleached  cotton  absorbs  less  moisture 
than  unbleached  cotton  in  all  cases.  This  is  probably  due  to  the  fact  that 
the  pectin  and  gums  on  the  fiber  take  up  a  greater  proportion  of  water  than 
pure  cellulose  itself.  In  another  set  of  experiments  Higgins  gives  the 
different  amounts  of  moisture  absorbed  by  cotton  mercerised  under 
various  conditions,  as  follows  • 

Percent. 

Ordinary  cotton 6 .  20 

Mercerised  with  caustic  soda  at  10°  Tw 6 .  37 

6.68 

8.40 

9.41 

9.43 

9.57 

70^  Tw 9.69 

Higgins  also  showed  that  cotton  cloth  which  has  thoroughly  dried  will 
not  absorb  the  amount  of  moisture  it  originally  contained  in  the  air-dry 
state,  even  after  long  exposure  to  the  atmosphere. 

16.  Lustering  of  Cotton  Materials. — In  order  to  increase  the  value 
and  appearance  of  cotton  fabrics,  many  attempts  have  been  made  to 
^Jour.  Soc.  Chem.  hid.,  1909,  p.  188 


20° 

Tw 

30° 

Tw 

"            40° 

Tw 

50° 

Tw 

60° 

Tw 

a                'jcio 

TtTT 

LUSTERING  OF  COTTON  MATERIALS  465 

give  cotton  a  high  luster.  This  histering  may  be  done  either  by  mechanical 
or  by  chemical  means.  In  the  latter  case  where  a  chemical  change  is 
brought  about  within  the  fiber,  the  processes  are  usually  dealt  with  under 
the  subject  of  mercerising.  There  are  also  other  chemical  processes  in 
which  the  fiber  is  coated  with  a  substance  having  a  high  index  of  refraction. 
There  is  also  the  more  modern  method  in  which  the  surface-cellulose  of  the 
fabric  is  converted  into  nitrocellulose  or  acetyl  cellulose.  According  to  U.  S. 
Pat.  954,310  the  cellulose  is  converted  into  acetylcellulose  by  being  treated 
with  a  mixture  of  anhydrous  acetic  acid  and  a  small  amount  (|  percent) 
of  sulfuric  acid.  The  result  is  that  the  fabric  is  waterproofed  and  lustered 
at  the  same  time.  Some  older  patents  protect  the  formation  of  a  lustrous 
coating  by  means  of  a  varnish  of  waste  silk  dissolved  in  alkahes  or  cuprate 
of  ammonia.  The  goods  to  be  lustered  were  soaked  with  the  silk  lye, 
and  then  the  silk  was  fixed  from  solution  by  treatment  with  a 
mineral  acid,  carbonic  acid,  or  a  bicarbonate  (Ger.  Pat.  64,457  and 
98,968). 

In  other  methods  the  silk  lye  is  replaced  by  solutions  of  collodion  or 
of  nitrocellulose  in  alkalis.  In  a  process  protected  by  Ger.  Pat.  24,795, 
the  outer  part  of  the  fiber  is  converted  into  nitrosaccharose.  The  worst  of 
these  methods  is  that  they  do  not  pay.  Hence,  barring  mercerisation, 
they  have  been  abandoned  in  favor  of  mechanical  methods.  The  oldest 
of  these  are  pressing  and  calendering,  and  the  first  great  improvement  on 
these  processes  was  the  invention  by  Robert  Deissler  (Ger.  Pat.  85,368  of 
1894)  of  engraved  calender  rolls.  The  finish  produced  by  their  use  has 
found  much  favor  under  the  name  of  Schreiner  finish,  or  silk  finish.  A 
later  improvement  consists  in  using  ribbed  rolls  set  at  an  angle  to  each 
other.  This  arrangement  gives  a  better  luster  with  blunter  edges  on  the 
cylinder  grooves.  The  action  depends  on  friction  at  an  angle  to  the 
length  of  the  warp.  Various  modifications  of  this  system  were  made 
with  the  idea  of  getting  a  luster  which,  in  addition  to  being  very  consider- 
able, should  also  be  fast  to  water  and  ironing.  In  Sharp's  English  patents, 
the  goods  are  covered  with  a  uniformly  damped  or  steamed  linen  blanket 
and  then  pressed  or  calendered  under  high  pressure.  In  Depierre's  method 
for  finishing  cotton  fabrics,  the  goods  are  calendered  while  still  damp  under 
heavy  pressure  with  hot  smooth  metal  rollers,  which  dry  and  luster  them 
at  the  same  time.  The  greasy  luster  thus  obtained  is  often  covered  by 
putting  the  fabrics  through  a  ribbed  calender  afterward.  In  the  patent 
of  Carl  Rumpf,  of  Elberfeld  (Ger.  Pat.  220,349),  strong  heating  of  the 
goods  is  mentioned  as  a  means  of  fixing  the  luster  fast  to  water  and  ironing, 
greasy  lustered  goods  being  run  in  a  state  of  tension  between  hot  rollers  or 
passed  in  a  state  of  tension  between  hot  rollers  or  passed  over  gas  flames. 
They  are  then  given  a  soap-and-water  bath  whereby  the  greasy  luster  is 
removed  and  the  silky  luster  which  has  been  superadded  remains  alone. 


466     THE  PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  COTTON 

In  a  later  patent  the  heating  is  made  to  produce  as  well  as  fix  the  luster, 
but  then  temperatures  above  400°  C.  are  necessary. 

Another  method  of  producing  luster  fast  to  water  and  ironing  is  the 
subject  of  Ger.  Pat.  88,946  of  1896.  The  fabric  is  soaked  with  a  solution  of 
albumen,  goffered  and  dried.  The  drying  coagulates  the  albumen  and 
fixes  the  goffering.  This  process  was  found  to  labor  under  the  practical 
difficulty  that  the  albumen  made  the  goods  stick  to  the  goffering  calenders. 
This  was  partly  remedied  by  the  invention  specified  in  Ger.  Pat.  206,901 
(F.  During),  according  to  which  the  calendering  is  done  with  rollers  which 
are  heated,  but  not  sufficiently  to  coagulate  the  albumen.  This  was  done 
by  further  heating  after  the  goods  had  left  the  calender.  At  the  same  time, 
the  luster  got  by  goffering  with  a  calender  not  very  hot  was  inferior,  and  the 
tendency  of  the  goods  to  stick  was  still  considerable,  especially  with  finely 
engraved  cylinders.  Hence,  in  the  additional  patent  {Ger.  Pat.  217,679), 
the  goods  were  dried  after  having  been  albumenised,  but  while  still  uncal- 
endered,  at  a  temperature  insufficient  to  coagulate  the  albumen.  The 
coagulation  was  then  effected  by  hot  calendering,  reinforced  by  steaming 
or  by  treatment  with  formaldehj'de.  To  prevent  too  much  stiffness,  oil 
may  be  added  to  the  albumen  solution,  which  may  also  be  applied  on  one 
side  only  of  the  goods. 

We  now  come  to  processes  in  which  the  lustered  surface  is  covered  and 
protected  by  an  independent  insoluble  waterproof  coating.  According  to 
Eck's  method  {Ger.  Pat.  232,568),  an  acid  solution  of  gelatine-formaldehyde 
is  applied  by  means  of  rollers,  and  coagulated  on  the  fabric  without  heat 
by  means  of  the  fumes  of  ammonia.  It  had  before  been  proposed  to  coat 
the  surface  of  the  goods  with  collodion  by  spraying  them  with  the  solution 
of  nitrocellulose  in  a  mixture  of  ether  and  alcohol.  The  film  thus  produced 
on  the  fabric  is  opalescent  owing  to  the  presence  of  water,  and  is  distinctly 
visible.  This  was  prevented  by  the  processes  described  in  Ger.  Pat. 
212,695  and  212,696,  which  make  the  collodion  solution  not  with  the  usual 
mixture  of  ether  and  alcohol,  but  with  amyl  acetate  or  amyl  formate, 
which  gave  liquids  which  contain  1  to  2  percent  of  nitrocellulose  and  can 
be  dyed  with  any  dye  soluble  in  the  amyl  salt.  Bernhard  Zittau  {Ger.  Pat, 
233,574)  uses  a  solution  of  India  rubber  or  guttapercha,  together  with 
paraffin-wax  or  ceresine  in  some  sort  of  hydrocarbon,  preferably  benzene. 

On  reviewing  these  attempts  to  make  a  mechanically  produced  luster 
fast  to  water  and  ironing,  we  note  that  the  result  is  produced  either  by 
powerful  heating  of  the  goods,  or  by  covering  their  fiber  with  an  insoluble 
coating.  Complete  fastness  to  ironing  and  damp  cannot  be  attained  by 
mere  heat  unless  the  temperature  is  so  high  as  grievously  to  endanger  the 
fiber. 


CHAPTER  XV 
CONSTITUENTS  OF  RAW  COTTON 

1.  Chemical  Constitution. — In  its  chemical  composition  cotton,  in 
common  with  the  other  vegetable  fibers,  consists  essentially  of  cellulose. 
On  the  sm'face  there  is  a  protecting  layer  of  wax  and  oily  matter  and  also 
in  the  fiber  there  is  a  trace  of  pigment  which  in  some  varieties  of  cotton 
becomes  quite  emphasised.  The  removal  of  these  substances  is  the 
object  of  the  boiling-out  and  bleaching  process  to  which  cotton  is  sub- 
jected prior  to  its  dyeing  and  printing.  In  reality  the  purified  cotton  fiber 
as  it  exists  in  bleached  material  is  practically  pure  cellulose,  and  this  com- 
pound alone  appears  to  be  essential  to  its  structural  organisation. 

The  cellulose  of  cotton  is  of  very  constant  composition  and  easy  to 
purify.  It  is  termed  normal  cellulose  to  distinguish  it  from  other  types  of 
cellulose  present  in  many  other  vegetable  fibers  where  the  cellulose  is  in 
combination  with  pectin  (linen  tj^pe)  and  lignin  (jute  type). 

2.  Impurities  in  Cotton. — The  natural  impurities  present  in  the  raw 
cotton  fiber  amount  to  about  4  to  5  percent,  and  consist  chiefly  of  pectic 
acid,  coloring  matter,  cotton-wax,  cotton-oil,  and  albmninous  matter. 
The  fiber  gives  about  1  percent  of  ash  on  ignition.  Bo-^man  is  of  the 
opinion  that  considerable  stress  should  be  laid  on  the  fact  that  the  cotton 
fiber  contains  about  1  percent  of  mineral  matter  as  an  integral  part  of  its 
constitution,  and  this  no  doubt  has  considerable  influence  on  its  structure 
and  properties.  It  is  usually  stated  that  cotton  j-arn  loses  from  5  to  7 
percent  of  its  weight  dming  purification  by  bleaching,  the  figure  for  cloth 
being  larger  by  the  amount  of  material  added  dm-ing  sizing.  Jecusco,^ 
for  example,  states  that  American  cotton  yarn  on  boiling  with  3  percent 
caustic  soda  and  2  percent  sulfated  oil  at  15  lbs.  for  eight  hours  loses  6.45 
percent,  the  loss  increasing  to  7.3  percent  on  full  bleaching.  Using  soda 
ash  instead  of  caustic  soda  and  following  with  a  stronger  hypochlorite 
solution,  the  loss  in  weight  was  7.1  percent.  Trotman  and  Pentecost- 
point  out  the  necessity  of  considering  the  moisture  present  before  and  after 
bleaching  in  working  out  figures  of  this  kind.     In  a  number  of  carefully 

1  Jour.  Soc.  Dyers  &  Col.,  1917,  p.  34. 
^  Jour.  Soc.  Chem.  Ind.,  1910,  pp.  4-6. 
467 


468 


CONSTITUENTS  OF   RAW  COTTON 


conducted  laboratory  experiments,  the  following  figures  were  obtained  for 
the  loss  during  the  soda  boil: 


Reputed  Count. 

Loss  Percent. 

Number  of  Tests. 

24/2  American 

5.30 

7 

32/2         "        

4.01 

36 

40/2         "        

4.35 

15 

70/2         "        

3.90 

29 

70/2  Egyptian 

6.54 

8 

80/2         "        

4.59 

12 

100/2         "        

4.35 

18 

120/2         "        

4.60 

12 

150/2         "        

4.55 

6 

The  comparative  effect  of  a  number  of  reagents  on  the  same  cotton 
under  standard  conditions  were  found  by  Trotman  and  Pentecost  to  be 
as  follows : 


Reagent. 

Loss  Percent. 

Potassium  hydroxide 

5.00 
4.40 
3.70 
2.80 
2.40 

Sodium  hydroxide 

Sodium  carbonate 

Sodium  borate 

Sodium  silicate 

The  oil  present  in  the  fiber  appears  to  be  identical  with  cottonseed-oil, 
and  is  probably  obtained  from  the  seed  to  which  the  fiber  is  attached. 

The  cotton-wax  serves  as  a  protective  coating  for  the  fiber  and  makes 
it  water-repellent,  as  is  evidenced  by  the  long  time  required  by  raw  cotton 
to  become  wetted-out  by  simply  steeping  in  water.  This  wax  appears  to 
be  closely  analogous  to  carnauba  wax ;  it  is  not  soluble  in  alkalies,  though 
it  may  be  gradually  emulsified  by  a  long-continued  boiling  in  alkaline 
solutions,  on  which  fact  is  based  the  "  boiling-out  "  of  cotton  by  the 
ordinary  methods.  Cotton-wax,  however,  appears  to  be  readily  soluble  in 
sulfated  oils,  such  as  Turkey-red  oil,  and  hence  cotton  may  be  rapidly 
and  thoroughly  wetted-out  by  using  a  solution  of  such  an  oil.  The  coating 
of  wax  over  the  cotton  fiber  appears  to  influence  its  spinning  qualities  to  a 
certain  extent,  as  it  requires,  for  instance,  a  rather  elevated  temperature 
to  successfully  spin  fine  yarns,  in  order  probably  to  soften  the  waxy  coating 
of  the  fiber.  As  the  temperature  falls  the  oily  wax  tends  to  become  stiff 
and  gummy  and  prevents  the  proper  drawing  of  the  fiber  in  spinning. 
Its  presence  among  the  thin  laminations  of  the  cell-walls  gives  a  greater 


IMPURITIES  IN  COTTON  469 

elasticity  to  the  fiber,  and  renders  it  less  liable  to  sudden  rupture.  The 
j2;radual  drying  up  of  the  more  volatile  portions  of  this  oil  in  the  fiber, 
leaving  the  remaining  portion  thicker  and  stiffer,  may  also,  and  probably 
does,  account  for  the  fact,  noticed  by  most  spinners,  that  new  crop  cotton 
seems  to  work  better  and  makes  less  waste  than  cotton  harvested  as  the 
season  advances.^  Spinning  trials  of  Egyptian  cotton  deprived  of  its 
wax  2  showed  that  the  material  behaves  very  badly  in  the  drawing  and 
spinning  processes,  giving  an  excessive  amount  of  waste,  irregular  results, 
and  showing  a  tendency  to  adhere  to  the  rollers.  Finer  counts  give  great 
trouble,  and  breakages  are  extremely  frequent.  In  the  loom,  as  warp, 
it  is  equally  troublesome.  Extraction  with  benzene  after  spinning,  how- 
ever, increases  the  strength,  but  diminishes  the  elongation  of  the  yarn  as 
shown  in  the  following  table: 


Increase  in  strength 

Decrease  in  elongation .  . 

^    ( Before . 
Average  counts  |  ^^^^^ 


American,  Percent. 

Egypt 

ian.  Percent. 

12.4 

11.0 

4.0 

9.9 

56.8 

58.1 

58.2 

58.9 

The  addition  of  2  percent  of  paraffin  wax  to  the  extracted  yarn 
decreases  its  tensile  strength  by  33  percent.  Yarn  spun  from  extracted 
cotton  is  from  24.5  to  27  percent  weaker  than  that  from  normal  cotton. 

The  fatty  acid  present  in  cotton-wax  has  been  found  to  be  identical 
with  margaric  acid.  According  to  Dr.  Schunck,  American  cotton  contains 
about  0.84  percent  of  fatty  matters,  whereas  East  Indian  cotton  contains 
only  0.337  percent. 

Analysis  of  cotton- wax  shows  it  to  consist  of  the  following : 

Percent. 

Carbon 80.38 

Hydrogen 14 .  51 

Oxygen 5.11 

It  fuses  at  85.9°  C,  and  solidifies  at  82°  C,  hence  it  bears  a  close  analogy  to 
both  cerosin,  or  sugar-cane  wax,  and  carnauba  wax. 

Cotton-gum  or  wood-gum  is  the  name  given  to  the  product  extracted 
from  cotton  by  boiling  alkali  and  not  precipitated  by  alcohol.  It  is  not 
equivalent  to  cotton-wax,  as  it  contains  not  only  the  latter  but  also  the 
pectic  and  fatty  matters  of  the  fiber. 

The  effect  on  the  cotton-wax  on  various  finishing  operations  in  the 

'  Bowman,  Cotton  Fiber,  p.  55. 
•^Joiir.  Text.  Inst.,  1911,  p.  22. 


470 


CONSTITUENTS  OF  RAW  COTTON 


manufacture  of  cotton  fabrics  is  found  to  be  of  considerable  importance. 
It  is  almost  impossible  to  obtain  the  effect  of  the  bettle  finish  if  wax  is  left 
in  the  cotton.  Even  the  trace  of  wax  left  after  scouring  and  bleaching 
may  be  sufficient  to  create  this  difficulty,  and  the  use  of  unsaponifiable 
material  in  sizing  the  warp  yarn  would  of  course  aggravate  the  trouble. 
For  this  reason,  extraction  with  suitable  solvents  is  strongly  recommended 
by  Fort  ^  and  a  process  has  been  patented  which  can  be  applied  before 
or  after  bleaching,  or  after  dyeing,  and  even  while  the  fabric  is  wet.^ 

To  show  the  effect  of  various  operations  on  the  wetting-out  of  cotton 
Beadle  and  Stevens^  pressed  various  samples  of  air-dried  cotton  into 
loose  wads,  15X10  mm.,  weighing  0.1  gram  each,  and  let  them  fall  from 
a  certain  height  on  to  the  surface  of  a  column  of  water.  The  time  taken 
to  pass  through  the  surface  was  used  as  a  measure  of  the  "  wetting  "  prop- 
erty of  cotton.     The  following  results  were  obtained: 

Cotton,  raw More  than  24  hours 

Cotton,  bleached  but  not  scoured 31 .3  seconds 

Cotton,  boiled  in  1.0  percent  NaOH 12 .3 

Cotton,  boiled  in  2.0  percent  NaOH 5.7 

Cotton,  boiled,  bleached  and  boiled  again .  .     4.0       " 
Cotton,  extracted  with  ether  and  alcohol ...     0.5     " 

The  removal  of  the  wax  is  one  of  the  principal  objects  of  the  lime  and 
soda  boils,  and  their  relative  efficiency  has  been  largely  debated.  It 
appears  to  be  generally  conceded  that,  as  a  single  operation,  the  soda  boil 
has  the  greater  effect,  as  indicated,  for  example,  by  the  following  table  of 
Trotman  and  Thorp,^  the  figures  being  the  percentages  of  ash,  etc.,  left 
in  the  fiber: 


Experiment  I. 

Experiment  II. 

Experiment  III. 

Soda 
Boil. 

Lime 
Boil. 

Soda 
Boil. 

Lime 
BoU. 

Soda 
Boil. 

Lime 
Boil. 

Ash 

Free  fat 

0.26 
0.10 
0.16 
0.05 

0.52 
0.26 
0.22 
0.07 

0.26 
0.20 
0.13 

0.50 
0.15 
0.21 

0.42 
0.16 
0.26 
0.07 

0.56 
0  11 

Fatty  acids  (as  soap) 

Nitrogen 

0.56 
0.07 

^Jour.  Soc.  Dyers  &  Col,  1921,  p.  161. 

2  Lumsden,  Mackenzie  and  Fort,  Brit.  Pat.  137,968. 

3  Jour.  Soc.  Chem.  Ind.,  1913,  p.  174. 

*  Bleaching  and  Finishing  of  Cotton  Goods,  p.  95. 


IMPURITIES  IN   COTTON  471 

It  is  when  the  lime  boil  is  considered  in  relation  to  the  lime-soiir-soda-sour 
sequence  that  opinions  differ.  Both  Higgins  ^  and  Trotman  and  Pentecost  ^ 
agree  that  in  the  lime  boil  and  saponified  portion  of  the  wax  is  hydrolysed 
and  that  the  subsequent  souring  converts  the  insoluble  soaps  left  on  the 
fiber  into  free  acids,  which  remain  in  close  contact  with  the  unsaponifiable 
matter,  so  that  in  the  lye  boil  a  soap  is  produced  and  rapid  emulsification 
and  eHmination  of  the  unsaponifiable  matter  result.  The  latter  authors 
consider,  however,  that  this  result  is  achieved  equally  well  by  the  direct 
soda  boil. 

Knecht  and  Allan  ^  found  that  the  benzene  extract  of  raw  cotton  could 
be  differentiated  by  means  of  petroleum  ether  into  "  soluble  cotton  wax  A  " 
and  "  insoluble  cotton  wax  B."  For  the  Egyptian  cotton  on  which  the 
main  investigation  was  conducted  the  ratio  was  72  percent  of  the  soluble 
wax  to  28  percent  of  the  insoluble,  while  for  an  American  cotton  it  was 
80  to  20  percent.  Cotton  Wax  A  is  odorless,  dull  yellow  in  color  and 
closely  resembles  beeswax  in  texture  and  fracture.  It  has  a  melting  point 
of  150°  to  154°  F.;  iodine  value  28.55;  acid  number  44.1  and  saponification 
value  84.3.  About  18.8  percent  is  undissolved  by  boiling  96  percent 
alcohol.  It  is  saponified  with  difficulty,  but  by  using  glycerol  and  sodium 
hydroxide  it  gives  47.5  percent  of  unsaponifiable  matter,  consisting  of  (a) 
hydrocarbons  (hentriacontane  (C3iH64)  and  dotriacontane  (C32II66)  were 
definitely  isolated) ;  (b)  a  phytosterol,  giving  an  acetyl  derivative  melting 
at  257°  F.,  but  otherwise  unidentified;  and  (c)  fatty  alcohols  unidentified 
owing  to  lack  of  material.  The  soap  yields  palmitic,  stearic,  and  cerotic 
acids.  Cotton  Wax  B  forms  a  dark  green  granular  mass,  with  a  melting 
point  of  154°  F.,  acid  number  4.03  and  saponification  number  83.3.  The 
unsaponifiable  portion  yields  33.5  percent  of  a  reddish  brown,  sticky  wax 
melting  at  145°  F.,  and  giving  on  acetylation  a  considerable  quantity  of  a 
phytosterol  acetate  with  a  melting  point  of  253°  F.  The  soap  yields  a 
small  proportion  of  melissic  acid. 

In  a  very  exhaustive  investigation  on  the  extractive  constituents  of 
American  cotton,  Fargher  and  Probert  ^  by  extraction  with  benzene 
showed  that  the  principal  constituent  is  a  new  alcohol,  to  which  they 
gave  the  name  gossypyl  alcohol,  with  the  formula  C30H62O.  The  dif- 
ferent substances  found  in  the  various  parts  of  the  crude  extract  are 
shown  in  the  following  table,  the  substances  present  in  relatively  large 
amounts  being  given  in  black-face  type  and  those  present  in  only  very  small 
amounts  in  italics: 

1  Bleaching,  p.  40. 

2  Jour.  Soc.  Chem.  Ind.,  1910,  pp.  4-6. 
» Jour.  Soc.  Dyers  &  Col,  1911,  p.  142. 
*  Jour.  Text.  Inst.,  1923,  p.  49. 


472  CONSTITUENTS  OF  RAW  COTTON 

CRUDE  BENZENE  EXTRACT  OF  RAW  AMERICAN   COTTON 

A.  Soluble  in  light  petroleum — 

1.  Sparingly  soluble — 

gamma-Gossypyl  alcohol 
beta-Gossypyl  alcohol. 

2.  Readily  soluble — 

Free  acids:  palmitic,  stearic  and  oleic. 

Acids  as  esters:  camaiibic,  palmitic,  stearic  and  oleic. 

Montanyl  alcohol,  gossypyl  alcohol. 

Solid  hydrocarbons:  triacontane,  hentriacontane . 

Liquid  hydrocarbons;  b.p.  170°-220°  C.  and  b.p.  150°-210°  C. 

Phytosterol,  principally  sitosterol. 

Amyrin. 

B.  Soluble  in  ether — 

1.  Sparingly  soluble — 

Montanyl  alcohol. 
Sitosterolin. 
Palmitic  acid. 
Stearic  acid. 

3.  Readily  soluble. 

Montanyl  alcohol. 
Palmitic  acid. 
Stearic  acid. 
C  Soluble  in  benzene — 

1.  Sparingly  soluble — 

beta-Gossypyl  alcohol. 

2.  Readily  soluble — 

heta-Gossypyl  alcohol,  palmitic  add,  stearic  acid. 

D.  Soluble  in  alcohol — 

1.  Sparingly  soluble — 

beta-Gossypyl  alcohol,  ceryl  alcohol. 

Sodium  salts  of  montanic,  cerotic,  palmitic  and  stearic  acids. 

2.  Readily  soluble — 

Sodium  salts  of  fatty  acids. 

E.  Soluble  in  chloroform — 

alpha-Gossypyl  alcohol,  carnailhyl  alcohol. 
an  acid,  C.34H68O2. 

In  obtaining  the  crude  benzene  extract  it  was  found  that  after  eight 
hours'  extraction  in  a  Soxhlet  apparatus  the  extract  amounted  to  0.47 
percent  calculated  on  the  air-dry  cotton  or  0.51  percent  calculated  on  the 
bone-dry  cotton.  The  extract  consisted  of  a  dark  brown,  plastic  mass 
with  the  following  characteristics: 

Melting  point 70°  to  75°  C. 

Density 0. 989 

Acid  value 30 . 6 

Saponification  value 65.0 

Saponification  value  after  acetylation 144 . 0 

Acetyl  value 83 . 0 

locHne  value 21.0 

Unsaponifiable  matter 51  percent 


IMPURITIES  IN  COTTON 


473 


Both  Knecht  and  Piest  ^  have  ascribed  reducing  properties  to  cotton 
wax,  as  it  appears  to  increase  the  "  copper  number  "  of  cotton.  The 
reducing  agent  may  be  similar  to  an  aldehyde  detected  by  Hoffmeister  ^ 
in  the  wax  of  flax. 

Hebden^  indicates  that  the  removal  of  fats  and  waxes  soluble  in 
ether  during  the  soda  boil  takes  places  as  follows : 


Steep. 

First  Boil. 

Second  Boil. 

Chemic. 

Sour. 

Percent. 

Percent. 

Percent. 

Percent. 

Percent 

5.5 

20.4 

64.0 

67.8 

69.6 

Trotman  and  Pentecost  *  give  the  following  typical  analyses  to  indicate 
the  difference  between  good  and  bad  soda  boils  of  cotton  goods: 


Mineral  matter 

Free  fat 

Fat  as  soap . .  . . 
Nitrogen 


After  Good  Boil, 

After  Bad  Boil, 

Percent. 

Percent. 

0.05-0.75 

1.00 

0.01-0.15 

0.35-0.70 

Trace 

0.25-0.50 

0.50-0.10 

0.25-0.35 

They  emphasise  the  utility  of  sodium  carbonate  and  of  borax  as  emulsi- 
fying agents,  but  consider  that  the  scouring  effect  of  sodium  silicate  is 
offset  by  possible  mechanical  damage  due  to  the  deposit  of  silica  on  the 
fiber.  Other  suggestions  for  the  more  effective  removal  of  waxes  include 
the  use  of  (a)  a  soap  solution  containing  benzene,^  (6)  a  mixture  of  potash 
soap,  carbon  bisulfide  and  olein,^  (c)  resin  soaps,  (d)  benzene  and  other 
solvents  brought  into  emulsion  with  Turkey-red  oil,  and  (e)  Turkey-red 
oil  and  oleic  acid.'^ 

Scheurer  ^  studied  the  saponification  of  tallow,  cottonseed  oil,  and  the 
fatty  constituents  of  raw  cotton  in  contact  with  cotton  cloth,  and  came 
to  the  following  conclusions:  (1)  Sodium  hydroxide  is  twice  as  effective  as 
sodium  carbonate  in  equivalent  concentration;  increasing  the  concentration 
of  alkali  from  5  to  10  parts  per  1000  is  without  sensible  effect;  (2)  mix- 
tures of  sodium  hydroxide  and  sodium  carbonate  show  maximum  efficiency 
when  the  proportion  of  carbonate  is  equivalent  to  25  percent  of  the  total 
alkali,  an  effect  which  is  ascribed  to  the  mechanical  properties  of  the 


^  Zeitsck.  angew.  Chem.,  1912,  p.  396. 
2  Ber.,  1903,  p.  1057. 
^Jour.  Ind.  Eng.  Chem.,  1914,  p.  714. 
*  Jour.  Soc.  Chem.  Ind.,  1910,  pp.  4-6. 


5  Chem.  &  Met.  Eng.,  1916,  p.  160. 
«  Dyson,  Brit.  Pat.  10,311,  1913. 
'  Bull.  Soc.  Ind.  Mulh.,  1903,  p.  288. 
8  Bull.  Soc.  Ind.  Mulh.,  1888,  p.  399. 


474 


CONSTITUENTS   OF   RAW   COTTON 


solution;  (3)  the  addition  of  rosin  increases  the  velocity  of  saponification, 
which  is  still  further  enhanced  by  increasing  the  concentration  of  the 
alkali;  (4)  the  saponification  of  cotton-seed  oil  in  contact  with  the  fabric 
is  relatively  rapid,  and  appears  to  increase  the  rate  of  saponification  of 
the  natural  fatty  constituents  of  the  raw  cotton;  (5)  neutral  fats  (tri- 
glycerides) are  much  more  rapidly  attacked  by  alkaline  solutiom  when 
mixed  with  readily  saponifiable  oils,  owing  probably  to  emulsi£cation ; 
(6)  while  the  rapidity  of  the  action  of  lime  is  noteworthy,  the  complete 
removal  of  the  fatty  matter  can  only  be  effected  by  a  subsequent  acidifica- 
tion and  boiling  with  sodium  carbonate;  (7)  the  general  statement  is 
made  that  complete  saponification  of  the  fatty  constituents  of  cotton 
may  be  effected  (a)  by  a  single  treatment  with  sodium  hydroxide  and 
rosin,  or  (6)  by  the  lime  "  sour  soda  ash  "  sequence,  the  latter  process 
having  the  greater  elasticity  and  certainty. 

Knecht  ^  considers  it  improbable  that  cotton  wax  is  saponified  under 
normal  bleaching  conditions,  the  wax  being  only  partially  removed,  and 
then  by  emulsification.  He  quotes  the  following  figures  in  support  of  the 
statement : 


Scouring  Agent. 


Soda  ash,  4°  Tw 

Sodium  hydroxide,  2°  Tw 

NaOH,  2°  Tw.+Castile  soap  (5  percent  of  weight 

of  cotton) 

NaOH,  2°  Tw.+Castile  soap  (5  percent  of  weight 

of  cotton) 

NaOH,  2°  Tw.+resin  soap  (5  percent  of  weight 

of  cotton) 


Time. 


4  hours 
4  hours 

25  minutes 

4  hours 

25  minutes 


Wax  Removed, 
Percent. 


30 

28 

45 
64 
73 


Although  the  use  of  resin  soap  appears  to  be  so  effective,  it  has  been 
suggested  that  if  the  water  used  contains  lime  or  magnesia,  resinates  may  be 
precipitated  on  the  fiber  and  eventually  produce  a  brown  color.^  The 
efficiency  of  potassium  hydroxide  compared  with  sodium  hydroxide  ^  and 
of  strontia  in  relation  to  lime  '*  has  been  considered.  Potassium  hydroxide 
is  said  to  remove  20  percent  more  wax  when  used  in  equimolecular  propor- 
tion for  the  same  time,  while  strontia  is  supposed  to  exert  a  saponifying 
action  three  times  as  great  as  that  of  lime  and  to  give  a  superior  general 
bleaching  effect.  There  is,  however,  the  possibility  of  tendering,  due  to 
oxidation. 


1  Jour.  Soc.  Dyers  &  Col,  1911,  p.  142. 

2  Jour.  Soc.  Chem.  Ind.,  1905,  p.  267. 


^  Jour.  Soc.  Chem.  Ind.,  1910,  pp.  4-6, 
^  Bull.  Soc.  Ind.  Mulh.,  1914,  p.  499. 


CHEMICAL  ANALYSIS   OF  RAW   COTTON  475 

The  retarding  effect  of  neutral  salts  and  of  hard  water  on  the  soda  boil 
is  considered  by  Trotman  in  a  later  communication.'  The  same  writer 
points  out  that  wax  retained  after  boiling-  may  protect  the  cotton  from 
the  action  of  the  ''  chemic,"  while  Graf "  considers  that  the  reducing 
agents  present  in  the  wax  cause  the  "  bleeding  "  of  vat  colors  in  the  lye 
boil,  and  indicates  methods  of  overcoming  this.  Kollman^  has  studied 
the  fall  in  reducing  power  of  raw  cotton  in  the  course  of  the  bleaching  proc- 
ess; the  greatest  change  taking  place  after  the  lye  boil,  when  the  majority 
of  the  secondary  constituents  are  removed.  Wliether  the  yellowing  of 
goods  in  storage  is  due  in  some  measure  to  the  wax  appears  to  be  unde- 
cided, Levine,"*  Crowther,^  and  Higgins  ®  favoring  the  assumption,  whereas 
Erban,'^  Hebden  and  Freiberger  ^  are  of  the  contrary  opinion. 

In  bleaching,  cotton  from  which  the  wax  has  been  previously  removed 
yields  a  "  white  "  much  superior  to  the  untreated  cotton.^ 

3.  Chemical  Analysis  of  Raw  Cotton. — The  following  table  gives  the 
analysis  of  the  cotton  fiber  from  reports  of  the  U.  S.  Department  of  Agri^ 
culture,  representing  the  average  of  a  large  number  of  tests: 

Percent. 

Water 6.74 

Ash 1.65 

Protein 1 .  50 

Fiber  (ceUulose) 83 .  71 

Nitrogen-free  extract 5 .  79 

Fat 0.61 

An  analysis  of  the  fertilising  constituents  present  in  the  cotton  fiber 
is  given  as  follows : 

Fertilising  Constituents 

Percent. 

Water 6.07 

Ash 1.37 

Nitrogen 0.34 

Phosphoric  acid 0.10 

Potash 0.46 

Soda 0.09 

Lime 0 .  19 

Magnesia 0 .  08 

Ferric  oxide 0 .  02 

Sulfuric  acid 0 .  60 

Chlorine 0.07 

Insoluble  matter 0 .  05 

^Jour.  Soc.  Chem.  Ind.,  1910,  p.  249.  ^  Jour.  Soc.  Dyers  &  Col,  1913,  p.  9. 

2  Ger.  Pat.  288,751  of  1914.  «  Jour.  Soc.  Chem.  Ind.,  1914,  p.  902. 

3  Papierfahrikant,  1910,  pp.  863,  890.  '  Fdrbcr  Zeit.,  1912,  p.  379. 

*  Jour.  Soc.  Dyers  &  Col.,  1908,  p.  106.         »  Zeitsch.  angew.  Chem.,  1916,  p.  397. 
9  Jour.  Soc.  Dyers  &  Col.,  1911,  p.  142. 


476  CONSTITUENTS  OF  RAW  COTTON 

The  composition  of  cotton  fibers  from  different  sources  may  be  said 
to  be  practically  the  same,  as  variations  in  the  reported  analyses  are  no 
greater  than  the  variations  to  be  observed  in  the  analyses  of  different 
samples  of  the  same  kind  of  cotton. 

Balls  ^  has  determined  the  specific  salinity  of  the  cell-sap  of  pure  strains 
of  Egyptian  cotton,  and  finds  a  salt  content  which  varies  not  only  with 
the  salinity  of  the  soil  but  also  with  the  variety  employed.  Plants  of  two 
Egyptian  strains  growing  with  interlacing  root  systems  showed  differences 
of  as  much  as  10.7  in  the  salinity  of  the  cell-sap. 

Lester  ^  has  studied  the  substances  present  in  raw  cotton  capable 
of  extraction  by  water.  This  extract  is  evidently  of  a  complex  nature 
and  amounts  to  about  1.73  percent  from  yarn,  though  if  the  cotton  yarn 
is  cut  up  into  short  lengths  (j  in.)  the  extractive  matter  rises  to  2.11 
percent.     The  analysis  of  this  extract  is  given  as  follows: 

Percent. 

Ash 39.22 

Fatty  acids  (by  HCl) 62.30 

Ether  extract 17 .  52 

Cold  water  extract 39 .  50 

Ash  of  original  cotton 0 .  82 

Ash  of  cotton  after  extraction  with  water 0.21 


Lester  also  shows  that  while  cotton  on  exposure  to  the  air  after  drying 
will  reabsorb  about  8  percent  of  moisture,  the  dried  aqueous  extract  from 
cotton  will  absorb  about  32  percent,  and  hence  is  of  a  far  different  nature 
from  that  of  cotton.  Prolmbly  raw  cotton  owes  some  of  its  hydroscopic 
moisture  to  this  substance. 

The  complete  chemical  analysis  of  cotton  may  be  conducted  as  follows : 
First,  the  hygroscopic  moisture  may  be  determined  by  drying  at  220°  F. 
(or  by  the  toluene  method  of  Schwalbe) ;  second,  a  weighed  portion  of  the 
fiber  is  incinerated  in  a  platinum  or  porcelain  crucible  to  a  complete  ash; 
this  will  give  the  ash  of  the  raw  fiber,  and  it  may  be  subsequently  analysed 
by  the  customary  chemical  methods  in  order  to  ascertain  its  composition. 
Another  portion  of  the  fiber  is  boiled  with  caustic  soda  solution  of  2°  Tw., 
rinsed,  and  dried;  the  loss  in  weight  is  considered  as  fat  and  wax.  Or  the 
fibers  may  be  extracted  with  alcohol  and  ether  in  a  Soxhlet  apparatus,  and 
the  extractive  matter  determined  by  loss  in  weight,  or  ascertained  directly 
by  evaporation  of  the  solvent.  The  amount  of  nitrogen  in  the  cotton  may 
be  determined  by  Kjehldahl's  method.  The  amount  of  cuticle  by  deter- 
mining the  loss  in  weight,  after  boiling  with  sodium  sulfite  solution.     The 


'  Proc.  Phil.  Soc,  17,  p.  4G7. 

"Jour.  Soc.  Chem.  Ind.,  vol.  21,  p.  388. 


CHEMICAL  ANALYSIS  OF  RAW   COTTON 


477 


ash  of    the  remaining    cellulose  can    then  be    determined.      A  resume 
of  the  complete  analysis  of  cotton  is  as  follows : 

(a)  Drj'  at  220°  F.=  hygroscopic  moisture. 

(6)  Ignite;  residue  =  ash  of  raw  fiber. 

(c)  Boil  with  caustic  soda  =  fat  and  wax. 

(d)  Bleach  with  sodium  hypochlorite  solution  =  coloring  matters. 

(f)   Boil  with  alkaline  solution  of  sodium  sulfite  =  cuticular  substance. 

(/)    Ignite;  loss  =  cellulose. 

ig)  Residue  of  ignition  =  ash  of  cellulose. 

Such  an  analysis  will  furnish  about  the  following  results: 

Percent. 

(a)  Hygroscopic  water ; 7 .  00 

(6)  Ash  of  raw  fiber 1.12 

(c)  Fats  and  wa.\ 5 .  00 

(d)  Loss  in  bleaching 0 .  50 

(e)  Cuticular  matters 0 .  75 

(/)    Rire  cellulose 86 .63 

(!7)  Ash  of  cellulose 0 .  12 

Knecht  has  made  very  exhaustive  tests  on  the  extraction  of  raw  cotton 
yarns  with  various  solvents  and  has  studied  the  extractive  matters  obtained 
thereby.^  The  cotton  material  experimented  with  consisted  of  good 
qualities  of  American  and  Egyptian  yarns  of  two-ply  40's  count,  containing 
8.03  and  7.37  percent  of  moisture,  respectively,  after  standing  in  an 
atmosphere  containing  70  percent  humidity.  The  amounts  of  ash  in  the 
samples  were  0.93  and  1.06  percent,  respectively.  The  following  table 
gives  the  percentages  of  extracts  obtained  with  the  different  solvents : 


Extractions. 

Knecht. 

Ivnecht  and  Hall. 

Knecht  and 
Fernandes. 

American. 

Egyptian . 

American . 

Egyptian. 

American . 

Egyptian. 

Benzene 

Alcohol 

Water 

0.55 
0.90 
1.61 
0.39 
0.72 
0.43 

0.47 
0.68 
1.40 
0.45 
0.46 

0.41 
0.53 
1.66 
0.43 
0.65 
0.66 

0.44 
0.74 
1.51 
0.50 
0.41 
0.59 

0.43 
0.54 
1.75 
0.41 
0.68 
0.58 

0.45 
0.75 
1  52 

Ammonia 

Formic  acid 

0.48 
0  47 

Hydrochloric  acid .  .  . 

0.57 

Similar  figures  are  given  by  Matthcs  and  Streicher  ^  who  found  that 
petroleum  ether  extracted  0.5  percent  from   Caravonica   cotton    (from 

^Jour.  Soc.  Dyers  &  Col,  1911,  p.  255,  and  1920,  p.  43. 
2  Pharm.  Zeulr.,  p.  637. 


478 


CONSTITUENTS  OF  RAW   COTTON 


North  Queensland),  0.36  percent  from  Egyptian,  and  0.34  percent  from 
American.  The  same  cottons  after  bleaching  yielded  0.25,  0.26,  and  0.32 
percent,  respectively.  Piest  ^  extracted  nine  samples  of  cotton  with 
ether,  carbon  tetrachloride,  and  alcohol,  and  obtained  small  amounts  of 
wax  varying  from  0.09  to  0.53  percent  and  Barnes  ^  has  found  that  ether 
extracts  from  0. 188  to  0.618  percent  from  various  Indian  cottons.  Knecht  ^ 
has  recently  noted  that  one  effect  of  destroying  the  fibrous  structure  of 
the  extracted  cotton  mechanically  is  to  release  a  further  quantity  of 
extractive  matter. 

Apart  from  the  wax,  little  is  known  about  the  material  extracted  save 
that  it  appears  to  contain  much  mineral  matter.  In  the  case  of  the  cotton 
yarns  examined  by  Knecht  ■*  the  alcoholic  extracts  were  amorphous,  brown, 
and  hydroscopic.  They  reduced  Fehling's  solution,  and  the  ashes  con- 
tained, respectively,  17.9  and  23.4  percent  of  potash,  KoO.  The  water 
extracts  were  similar,  but  did  not  reduce  Fehling's  solution  so  readily. 
They  contained,  respectively,  50.4  and  54.5  percent  of  mineral  water. 

Higgins  ^  states  that  if  cotton  or  linen  is  completely  extracted  with 
benzene,  then  treated  with  acid,  washed  and  dried  again,  a  further  quantity 
of  fatty  acid,  about  10  percent  of  the  first  amount  of  wax,  may  be  obtained 
by  boiling  with  benzene.  The  acid  washings  contain  magnesium,  from 
which  the  conclusion  is  drawn  that  some  of  the  fatty  acid  is  present  as  a 
magnesium  salt,  Knecht  also  reports  that  after  extracting  cotton  with 
benzene  and  then  bleaching,  a  further,  but  smaller,  extract  can  be  ob- 
tained. 

The  chief  portion  of  the  mineral  matters  present  in  the  raw  fibers  is 
to  be  found  in  the  water  and  alcohol  extractions,  as  shown  by  the  ash 
content  of  these  extracts,  as  follows 


Extract. 

Ash  Content  in  Percent. 

American. 

Egyptian. 

Alcohol , 

Water 

40.73 

48.27 

42.. 55 
50.09 

The  affinity  of  the  cotton  toward  basic  dyes  shows  no  diminution  after 
successive  extraction  with  benzene,  alcohol,  and  water.     With  tannic  acid, 

1  Zeilsch  angew  Chevi.,  1921,  p  396.  ^  Jour  Soc.  Dyers  &  Col.,  1920,  p.  279. 

=  Dabney,  The  Cotton  Plant.  *  Jour.  Soc.  Dyers  <fc  Col ,  1918,  p.  220 

f-  Bleaching,  p.  13, 


COLORING   MATTER   IN   COTTON 


479 


on  the  other  hand,  the  extracted  cotton  shows  a  less  degree  of  absorption 
and  also  less  power  to  retain  that  tannic  acid  absorbed.  These  results  are 
shown  in  the  following  tables : 

REACTION  WITH  TANNIC  ACID 


• 

American. 

Egyptian. 

Extraction. 

Absorbed, 
Gram. 

Retained 

After  Rinsing, 

Gram. 

Absorbed, 
Gram. 

Retained 

After  Rinsing, 

Gram. 

Original 

Benzene 

Alcohol 

Water 

0.0395 
0.0326 
0.0291 
0.0208 

0.0295 
O.0028 
0.0026 
0.0019 

0.0421 
0.0339 
0.0307 
0.0266 

0.0240 
0.0063 
0.0039 
0  0066 

It  is  evident,  therefore,  not  only  that  less  tannic  acid  is  absorbed  by 
the  extracted  cotton  but  that  it  is  also  more  loosely  held  in  combination. 
The  effect  of  the  extractions  on  the  tensile  strength  is  shown  as  follows: 


EFFECT  OF  EXTRACTIONS  ON  TENSILE  STRENGTH 


American. 

Egyptian. 

Extraction. 

Conditioned, 
Ounces. 

Dried  at 
100°  C, 
Ounces. 

Conditioned, 
Ounces. 

Dried  at 
100°  C, 
Ounces. 

Original 

Benzene 

Alcohol 

Water 

12.19 
15.19 
14.59 
16.12 

13.32 
14.52 
14.37 
15.92 

15.34 
18.02 
17.10 
15.45 

15,51 
16.01 
16.81 
15.59 

One  remarkable  result  in  this  connection  is  that  the  strength  of  the 
original  cotton  in  the  dried  condition  is  greater  than  when  the  fiber  has 
its  normal  amount  of  hydroscopic  moisture. 

4.  Coloring  Matter  in  Cotton. — The  coloring  matter  of  cotton  has  been 
investigated  and  has  been  found  to  consist  of  two  organic  pigments,  the 


480 


CONSTITUENTS  OF  RAW  COTTON 


one  easily  soluble  in  alcohol  and  the  other  dissolved  only  by  boiling  alcohol. 
According  to  Schunck/  the  composition  of  these  bodies  from  Nankin 
cotton  is  as  follows : 


A.  Soluble  in 

Cold  Alcohol, 

Percent. 

B.  Insoluble  in 

Cold  Alcohol, 

Percent. 

Carbon 

Hydrogen 

Nitrogen 

Oxygen 

58.22 
5.42 
3.73 

32.63 

57.70 
5.60 
4.99 

31.71 

The  composition  of  the  analogous  coloring  matters  in  American  cotton  is 
practically  identical  with  the  above. 

There  is  a  peculiar  variety  of  peeler  cotton  known  as  blue  bender  cot- 
ton. This  fiber  is  characterised  by  a  bluish  color  which  cannot  be  bleached 
out  by  the  usual  methods  employed  for  the  bleaching  of  ordinary  cotton. 
It  receives  its  name  from  occurring  in  the  "  bends  "  of  the  Mississippi 
River  valley.  The  exact  nature  of  the  color  and  the  cause  of  its  formation 
in  this  variety  of  cotton  are  not  known.  By  some  it  is  supposed  that 
the  defect  arises  from  the  plant  being  touched  by  frost  too  early,  while 
others  assume  that  the  cause  is  to  be  found  in  some  ingredient  in  the  soil. 
Outside  of  its  defective  color  and  resistance  to  bleaching,  the  appearance 
and  quality  of  the  fiber  are  otherwise  unimpaired. 

It  is  a  common  opinion  that  brownish  colored  cottons  contain  more 
iron  than  lighter  colored  varieties.  It  appears,  however,  that  the  ash  of 
dark  colored  cottons  does  not  contain  a  greater  proportion  of  iron.  The 
coloring  matter  is  altogether  an  organic  pigment.^ 

Penot  ^  observed  that  the  coloring  matter  of  cotton  is  soluble  in  alkalies, 
but  not  immediately;  air  and  light,  or  chlorine,  being  necessary  for  its 
complete  removal.  Schunck'^  and  Knecht  ^  have  isolated  highly  colored 
products  containing  nitrogen  to  which  they  are  inclined  to  ascribe  the 
color,  but  the  conditions  under  which  they  were  obtained,  by  soda  ash 
and  caustic  soda  boils,  respectively,  together  with  the  analyses  recorded 
by  Schunck,  render  it  probable  that  they  are  decomposed  proteins.  Still, 
it  is  possible  that  the  coloring  matter  may  occur  in  combination  with 
protein.  Taylor  ^  has  noted  that  the  coloring  matter  present  in  cotton 
is  eliminated  completely  by  the  use  of  a  hypochlorous  acid,  or  a  hypochlor- 


1  Chem.  News,  1868,  p.  118;  1874,  p.  5. 
''Also  see  Kuhn,  Die  Baumwolle,  p.  138. 
»  Bull.  Soc.  Ind.  Mulh..  1836,  p.  369. 


*  Manchester  Lit.  Phil.  Soc,  1871,  p.  95. 
6  Jour.  Soc.  Dijers  &  Col,  1918,  p.  220. 
«  Jour.  Soc.  Dyers  &  Col.,  1914,  p.  85. 


PECTIN   COMPOUNDS   IN   COTTON  481 

ite  alone,  and  has  drawn  the  conclusion  that  two  coloring  matters  are 
present. 

The  pigment  of  cotton  is  most  pronounced  in  wild  varieties,  the  hairs 
of  which  are  more  or  less  colored  by  a  reddish  endochrome,  especially  in 
the  parts  more  exposed  to  light.  The  color  deepens  as  the  cotton  ripens, 
and  W.  L.  Balls  ^  states  that  a  profound  change  occurs  at  about  the 
twenty-seventh  day  of  the  development  of  the  boll.  The  young  bolls 
"  pickle  "  in  a  mixture  of  alcohol  and  acetic  acid  to  a  green  color,  but  the 
older  bolls  give  a  pink  or  bright  red  "  pickle,"  and  later,  when  the  fruit  is 
beginning  to  burst,  the  "  pickle  "  is  brown.  The  color  is  increased  by 
exposure  to  diffused  light,  but  is  often  destroyed  by  sunlight,  especially 
when  the  protoplasm  is  dead.     It  is  also  deepened  by  steaming.^ 

In  a  recent  communication^  Brabhaj  states  that  cottons  varying  in 
color  from  light  green  to  dark  brown  have  been  cultivated.  The  fibers 
are  extremely  fine,  and  the  brown  variety  is  said  to  surpass  in  fineness 
any  cotton  hitherto  produced. 

The  pigment  is  found  chiefly  in  the  lumen,  but  is  also  in  association 
with  the  cellulose.  Brazilian  and  South  American  cottons  contain  very 
little,  but  Egyptian  cotton  is  so  much  richer  in  pigment  that  it  can  be 
readily  distinguished  thereby. 

It  is  not  known  whether  the  pigment  bears  any  relation  to  the 
"  gossypol  "  of  cotton  seed  ^  or  to  the  glucosides  found  by  A.  G.  Perkin  ^  in 
cotton  flowers. 

5.  Pectin  compounds  in  Cotton. — Pectin  compounds  form  the  greater 
portion  of  the  impurities  present  in  cotton,  and  are  very  complex  in  nature. 
The  term  pectin  is  a  rather  broad  one  in  a  chemical  sense,  and  relates  to 
that  class  of  bodies  in  fruit  or  plant  juices  that  produce  jelly-like  com- 
pounds. The  chemical  natm'e  and  properties  of  the  pectins  are  but  little 
understood.  The  pectins  form  salts  with  metallic  bases,  so  we  may  have 
calcium  pectate,  sodium  pectate,  and  the  like.  When  raw  cotton  is 
kier-boiled  with  caustic  soda  or  caustic  lime  it  is  supposed  that  the  pectin 
compounds  are  broken  up  from  their  complex  organic  combinations 
within  the  fiber  and  form  sodium  or  calcium  pectate.  The  gelatinous 
nature  of  cotton  pectin  is  observable  in  the  brown  jelly-like  masses  to  be 
found  in  the  course  of  kier-boiling. 

Schunck  isolated  from  among  the  products  removed  from  cotton 
by  the  soda  ash  boil  considerable  quantities  of  a  substance  corresponding 
with  the  "  para-pectic  acid  "  described  earlier  by  Fremy.     More  recently, 

^  Development  and  Properties  of  Raw  Cotton,  p.  71. 

2  Text.  Mer.,  1914,  p.  85. 

3  Dyer  &  Calico  Ptr.,  1920,  p.  20. 

*  Jour.  Amer.  Chem.  Soc,  1918,  p.  647. 
6  Jour.  Chem.  Soc.,  1909,  jj.  2181. 


482  CONSTITUENTS  OF  RAW  COTTON 

Knecht  ^  obtained  a  similar  product  from  the  caustic  soda  boil  which  had 
been  previously  lime-boiled  and  soured.  The  material  so  obtained  has 
received  little  attention,  and  the  considerable  literature  on  such  products 
which  has  accumulated  during  the  last  decade  is  concerned  chiefly  with 
the  pectic  substance  of  sugar  beet  and  of  fruit  juices. 

On  treatment  with  warm  dilute  sodium  hydroxide,  pectin  loses  methyl 
alcohol  and  is  converted  into  pectic  acid  which  is  very  soluble  in  alkali 
hydroxides,  carbonates,  or  phosphates,  and  in  most  ammonium  salts  of 
organic  acids.  Ammonium  oxalate  gives  a  limpid  solution,  but  alkali 
carbonates  give  mucilages.  Its  solutions  in  water  are  flocculated  by  the 
addition  of  salts.  More  prolonged  action  of  alkali  leads  to  meta-pectic 
acid,  the  ultimate  product  of  the  action  of  the  usual  bleaching  agents. 
Pectic  substances  are  almost  entirely  removed  from  the  fiber  in  the  scouring 
operations,  which  probably  affect  the  decomposition  of  metallic  salts. 
In  a  recent  process  "  it  is  proposed  to  eliminate  pectic  matter  by  the  use 
of  hot  hydrochloric  acid;  it  is  claimed  that  the  fiber  is  not  seriously  weak- 
ened by  the  treatment.  Ehrlich's  work  indicates  that  the  pectin  of  the 
cell  membranes  of  plants  is  the  calcium-magnesium  salt  of  a  complex 
anhydro-arabino-galactose-methoxy-tetragalacturonic  acid.  There  is  no 
evidence  as  to  the  mode  of  linking,  save  that  the  arabinose  group  is  weakly 
and  the  galactose  group  strongly  held.  Gartner  considers  that  pectic  acid 
is  a  galactose-galacturonic  acid,  rather  than  a  tetragalacturonic  acid. 

6.  Mineral  Matter  and  Ash  in  Cotton. — The  quantity  of  ash  (mineral 
matter)  in  raw  bale-cotton  will  average  considerably  higher  than  that 
obtained  from  the  purified  fiber;  this  is  due  to  adhering  sand  and  dust 
which  are  nearly  always  present.  The  following  table  shows  the  amount 
of  ash  contained  in  samples  of  difl'erent  varieties  of  cotton : 

Percent. 

Dhanvar 4.16 

Dhollerah 6.22 

Sea-island 1 .  25 

Peruvian  (soft) 1 .  68 

* '         (rough) 1 .  15 

Bengal 3.98 

Broach 3 .  14 

Oomrawuttee 2 .  52 

Egyptian  (brown) 1 .  73 

(white) 1 .  19 

Pemambuco 1 .  60 

American 1 .  52 

Monie  gives  a  table  showing  the  percentage  of  sand  or  mineral  matter 
contained  in  bales  of  commercial  cotton  as  they  arrive  at  Liverpool. 

1  Jour.Boc.  Dyers  &  Col.,  1918,  p.  220 

2  Bnt.  Pat.  104,202  of  1916. 


MINERAL  MATTER  AND  ASH   IN   COTTON 


483 


Percent. 

Sea-island 1 .  10 

Rough  Peruvian 1 .  25 

Gallini  Egyptian 1 .  25 

Brown  Egyptian 1 .  60 

Orleans 1 .  60 

White  Egyptian 1.75 

Smooth  Peruvian 1 .  80 

Pernambuco 1 .  98 

Texas 2.10 


Percent. 

Upland 2.10 

Bahia 2.16 

Hingunghat 2.33 

Broach 2.58 

Oomrawuttee 2 .  93 

African 3.20 

Dhollerah 4 .  10 

Comptah 4 .  18 

Bengal 5.30 


It  is  to  be  presumed  that  Monie  did  not  include  in  the  above  figures  the 
amount  of  mineral  matter  in  cotton  as  obtained  from  the  ash  of  the  purified 
fiber,  but  that  his  figures  represent  the  sand  or  other  foreign  mineral 
matter  mechanically  held  in  the  baled  cotton. 

When  the  amount  of  ash  is  found  to  be  much  over  1  percent,  the 
excess  may  be  considered  as  mechanically  attached  sand  and  dust.  Barnes 
contends  that  this  is  incorrect;  twelve  Indian  cottons,  he  found,  average 
2.48  percent;  the  extreme  values  being  1.34  and  3.99.  The  amounts  of 
silica  and  chlorine  present  were  in  accord  with  the  figures  for  total  ash. 
Five  samples  of  American  cotton  gave  values  ranging  from  1.18  to  1.92, 
while  two  Egyptian  samples  gave  1.37  and  1.50,  respectively.  On  the 
other  hand,  a  two-ply  60's  American  cotton  examined  by  Knecht  ^  con- 
tained only  0.93  percent,  a  similar  Egyptian  sample  1.17,  and  a  soft  twist 
Egyptian  0.89  percent  of  ash.  Two  complete  analyses  of  the  ash  are 
quoted  by  Barnes,  as  follows: 


Bombay, 
Percent. 

Punjaub, 
Percent. 

Moisture  in  original  fiber 

2.23 
3.99 

15.56 

10.80 
5.89 
9.75 
1.87 

27.32 
4.51 
1.96 
3.26 

12.19 
6.55 
0.34 

3  78 

Total  ash  in  dry  fiber 

1.85 

Constituents  of  the  ash :  SiOz 

AI2O3 

FejOa 

CaO 

MgO 

K2O 

14.40 
12.87 

1.92 
10.65 

4.36 
26.03 

NazO 

SO3 

P2O5 

CO2 

CI 

Undetermined 

8.40 
2.52 
4.46 
8.03 
3.84 
2.52 

Jour.  Soc.  Dyers  &  Col,  1918,  p.  220. 


484 


CONSTITUENTS  OF  RAW  COTTON 


The  true  ash  of  the  cotton  fiber  consists  principally  of  the  carbonates, 
phosphates,  chlorides,  and  sulfates  of  potassium,  calcium,  and  magnesium, 
as  is  exhibited  by  the  following  analysis  of  Dr.  Ure : 

Percent. 

Potassium  carbonate 44 .  80 

' '  chloride 9 .  90 

' '         sulfate 9 .  30 

Calcium  phosphate 9 .  00 

' '        carbonate 10 .  60 

Magnesium  phosphate 8 .  40 

Ferric  oxide 3 .  00 

Alumina  and  loss 5 .  00 

Mitchell  and  Prideaux  ^  give  analyses  of  typical  specimens  of  cotton, 
as  follows: 


Variety  of  Cotton. 

Moisture, 
Percent. 

Mineral  Matter, 

Including  Sand, 

Percent. 

Phosphoric  Acid 
as  P2O6, 
Percent. 

Sea-island 

7.83 
7.70 

8.85 
7.27 
7.89 

2.21 
2.05 

2.08 
2.86 
3.30 

0  22 

Orleans 

Pernambuco 

Indian  (Oomaa) 

0.18 
0.37 
0  23 

Indian  (Bengal) 

0.15 

The  analyses  of  Davis,  Dreyfus,  and  Holland,  reported  as  a  mean  from 
twelve  different  varieties  of  cotton,  show  a  little  difference  from  the 
above  analyses,  especially  in  having  present  sodium  carbonate  as  one  of 
the  constituents.     The  mean  of  these  analyses  is  given  as  follows: 

Percent. 

Potassium  carbonate 33 .  22 

"  chloride 10.21 

sulfate 13 .  02 

Sodium  carbonate 3 .  35 

Magnesium  phosphate 8 .  73 

' '  carbonate 7.81 

Calcium  carbonate 20 .  26 

Ferric  oxide 3 .  40 

According  to  Calvert,^  cotton  samples  from  different  countries  contain 
the  following  percentages  of  phosphoric  acid  soluble  in  water: 

Egypt 0.055  Surat 0.027 

New  Orleans 0 .  040  Carthagena 0 .  035  to  0 .  050 

Bengal 0.055  Cyprus 0.050 

It  is  sometimes  found  that  mercerised  Egyptian  cotton  contains  a  larger 
percentage  of  iron  than  is  naturally  present  in  the  untreated  fiber.     This 
^Fibers  Used  in  Textile  Industries,  p.  96.  ^  Jour,  prakt.  Cheni.,  1869,  p.  122. 


MINERAL   MATTER  AND  ASH   IN   COTTON 


485 


is  doubtless  caused  by  the  presence  of  iron  in  the  caustic  soda  solution 
employed  for  the  mercerisation ;  sodium  ferrate,  in  fact,  appears  to  be  a 
normal  constituent  of  such  solutions,  being  derived  from  the  solvent  action 
of  caustic  soda  on  the  iron  rust  present  in  the  tanks.  Lefevre  ^  gives  the 
following  analyses  of  samples  of  mercerised  Egyptian  cotton: 


Kind  of  Cotton. 

Ash, 
Percent. 

Oxide  of  Iron,  in 
Ash,  Percent. 

Color  of  Ash. 

Natural  Egjqatian 

Mercerised  Egyptian 

Gray  mercerised  Egyptian 

Bleached  mercerised  Egyptian 

0.624 
0.137 
0.403 
0.088 

1.50 
8.02 
2.31 
5.45 

T^Tiite 

Greenish 

Yellow  gray 

Greenish 

The  mineral  matter  present  in  cotton  is  speedily,  but  not  completely, 
eliminated  during  the  usual  bleaching  operations,  the  total  loss  at  each 
stage  being  given  by  Hebden  -  as  follows : 

Steep.        First  Boil.        Second  Boil.        Chemic.        Sour. 

Percent.         Percent.  Percent.  Percent.      Percent. 

70.5  87.3  95.4  93.0  95.0 

Knecht^  reports  that  after  lime  boil,  sour,  soda  boil,  sour,  chemic 
and  sour  with  hydrochloric  acid,  the  ash  of  a  soft  twist  Egyptian  sample 
had  decreased  from  0.89  to  0.15  percent. 

Lester  ^  has  compared  the  ash  from  the  aqueous  extract  of  cotton  with 
that  of  the  cotton  itself.  The  latter  contained  0.82  percent,  and  0.61 
percent  was  removed  by  the  extraction.     The  constituents  were  as  follows : 


Magnesium  carbonate. 

' '  phosphate 

Alumina 

Iron  oxide 

Silica 

Calcium  carbonate 

Sodium  carbonate .... 
Potassium  carbonate . . 

"         sulfate.  .  .  . 

"  chloride.  .  . 
Sodium  sulfate 


Ash  of  Water 

Ash  of  Cotton, 

Extract,  Percent. 

Percent. 

6.84 

5.11 

2.65 

13.10 

3.90 

3.90 

Trace 

2.71 

1.79 

1.00 

3.80 

13.50 

27.78 

15.90 

13.82 

36.9 

32.2 

2.60 

2.5 

4.6 

4.6 

'  Jour.  Soc.  Dyers  dk  Col.,  1918,  p.  220. 
'  Text.  Mer.,  Dec,  1904. 


1  Rev.  Gen.  Mat.  Col,  1909,  p.  281. 

2  Jour.  Ind.  Eng.  Chem.,  1914,  p.  714. 


486  CONSTITUENTS  OF  RAW  COTTON 

Lester  considers  the  hydroscopic  properties  of  cotton  to  be  due  to  some 
extent  to  the  material  extracted  by  water.  Grace  Calvert  ^  found  that 
nearly  the  whole  of  the  phosphorus  was  removed  by  cold  water  extraction, 
and  determined  the  phosphate  content  of  a  number  of  cottons.  The  per- 
centages of  soluble  phosphate,  calculated  at  P2O5,  are  as  follows: 

Percent.  Percent. 

Egypt 0.055  Carthagena 0.035 

New  Orleans 0.049  Macao 0.050 

Bengal 0.055  Cyprus 0,050 

Surat 0.027 

Wlien  a  sample  of  lint  is  burnt,  the  skeletal  structure  is  preserved  in  the 
ash,  which  suggests  that  the  mineral  substances  are  present  in  the  tissue 
of  the  fiber  itself  rather  than  as  dricd-up  cell-sap. 

7.  Nitrogenous  Matter  in  Cotton. — The  albuminous  or  nitrogenous 
matter  present  in  cotton  is  only  of  very  small  amount,  and  doubtless  con- 
sists of  protoplasmic  residue.  Different  varieties  of  cotton,  on  analysis, 
show  the  following  percentages  of  nitrogen ;  some  of  this,  however,  may  be 
derived  from  mineral  nitrates  which  may  be  present  in  slight  amount  in 
the  fiber  (Bowman): 

Percent  Nitrogen. 

American 0 .  30 

Sea-island 0. 34 

Bengal 0 .39 

Rough  Peruvian 0.33 

Egyptian  (white) 0.29 

(brown) 0.42 

Mean 0.345 

According  to  analyses  by  Schindler,^  raw  Egyptian  cotton  gave  2.50 
percent  of  nitrogen.  By  boiling  the  cotton  for  eight  hours  with  caustic 
soda  solution  the  amount  of  nitrogen  was  reduced  to  0.064  percent. 

It  is  likely  that  in  the  process  of  bleaching  most  of  the  albuminous 
matter  is  removed  from  the  cotton  fiber.  Haller  has  shown  that  bleached 
cotton  is  not  tinted  so  deeply  as  raw  cotton  with  an  acid  solution  of 
Safranine,  and  he  concludes  that  this  is  due  to  the  albuminous  matter 
acting  as  a  mordant  for  the  dyestuff. 

The  amount  of  nitrogenous  matter  present  in  cotton  may  be  determined 
by  Kjehldahl's  process,  as  follows:  5  grams  of  cotton  material  is  chopped  up 
and  heated  in  a  flask  with  30  cc.  of  concentrated  sulfuric  acid  and  2  grams 
of  potassium  permanganate.     This  treatment  results  in  a  complete  decom- 

1  Jour.  Chem.  Sac,  1867,  p.  303. 
^Jour.  Soc.  Dyers  &  Col,  1908,  p.  106. 


NITROGENOUS   MATTER  IN   COTTON 


487 


position  of  the  nitrogenous  matter  with  the  hberation  of  ammonia,  which 
immediately  combines  with  tlie  sulfuric  acid  present  to  form  ammonium 
sulfate.  An  excess  of  caustic  soda  solution  is  now  carefully  added,  and 
the  solution  boiled.  This  results  in  the  liberation  of  free  ammonia  as  a 
gas.  The  latter  is  passed  into  a  definite  volume  of  to  normal  sulfuric 
acid  solution,  and  the  excess  of  acid  not  neutralised  by  the  ammonia  is 
subsequently  titrated  with  yV  normal  caustic  soda  solution,  using  methyl 
orange  as  an  indicator.  The  amount  of  sulfuric  acid  neutralised  measures 
the  quantity  of  ammonia  formed,  which  in  turn  determines  the  amount 
of  nitrogen  present  in  the  original  cotton.  The  quantity  of  nitrogen  so 
obtained  multiplied  by  the  factor  6.4  gives  the  amount  of  nitrogenous 
matter  present  as  an  albuminoid. 

Rather  recent  tests  on  typical  cotton  furnished  the  following  results: 
American  cotton  gave  0.138  percent  of  nitrogen;  Texas  cotton  0.150  per- 
cent, and  red  Peruvian  0.280  percent. 

Knecht  ^  has  examined  the  removal  of  nitrogenous  constituents  by 
extraction  with  a  number  of  solvents,  his  results  with  an  American  cotton 
containing  0.204  percent  being  as  follows: 


After  Successive  Extraction  with 


Benzene 

Alcohol 

Water 

Ammonia  (dilute) 

Formic  acid  (dihite) 

Hydrochloric  acid  (2°  Tw.) 
Bleaching  powder  (2°  Tw.) 


Nitrogen  Content. 

American, 

Egyptian, 

Percent. 

Percent. 

0.189 

0.240 

0.184 

0.226 

0.175 

0.218 

0.175 

0.218 

0.168 

0.211 

0.138 

0.175 

0.022 

0.037 

Treatment  with  inert  solvents  thus  accounted  for  14.1  and  16.7  percent 
of  the  nitrogen  in  the  respective  complex,  and  chemical  treatment  for 
72.3  and  71.3  percent. 

Knecht  and  Fernandez  ^  have  suggested  that  as  an  albuminoid  has 
been  obtained  from  raw  cotton,  dye  affinity  may  be  attributed  to  a  definite 
substance,  and  in  this  connection  it  is  worth  recording  that  R.  J.  Flintoff  ^ 
has  discussed  the  function  of  added  albuminoids  as  fixing  agents  in  the 

'^Jour.  Soc.  Drjers  &  Col,  1918,  p.  220. 
^Jour.  Soc.  Dyers  &  Col.,  1920,  p.  43. 
» Jour.  Soc.  Chem.  Ind.,  1896,  p.  235. 


488  CONSTITUENTS  OF  RAW  COTTON 

dyebath.  Haller  ^  has  also  shown  that  there  is  a  substance  in  the  cotton 
fiber  which  has  an  affinity  for  stannous  chloride. 

The  effect  of  bleaching  operations  on  the  nitrogenous  constituents  has 
been  examined  by  Schindler,^  who  found  that  after  boiling  with  sodium 
hydroxide  of  2°  Tw.  for  eight  hours  the  nitrogen  content  of  an  Egyptian 
cotton  was  reduced  from  0.250  to  0.065  percent.  Increase  of  the  concen- 
tration of  sodium  hydroxide  to  10°  Tw.  reduced  the  nitrogen  to  0.028 
percent,  while  further  treatment  with  bleaching  powder  of  1.5°  Tw. 
reduced  it  to  0.003  percent.  Using  a  still  stronger  solution  of  sodium 
hydroxide  (77°  Tw.),  the  percentage  of  nitrogen  was  reduced  to  0.016  to 
0.019.  Most  of  the  nitrogen  expelled  from  the  cotton  remained  in  some 
form  in  the  solution,  and  was  not  isolated  as  ammonia.  The  figures 
obtained  by  Higgins  for  the  elimination  of  nitrogen  as  ammonia  by  the 
method  of  Osborne,  Leavenworth,  and  Brautlecht  confirm  this,  an  Ameri- 
can yarn  yielding  only  0.018  percent,  and  an  Egyptian  0.034  percent,  of 
nitrogen  as  ammonia. 

Knecht  ^  gives  the  following  figures  for  the  various  stages  of  the  bleach- 
ing process,  the  nitrogen  being  expressed  in  terms  of  that  originally  present : 

Percentage  of  Nitrogen 
After  Originally  Present  which 

Survives  Treatment. 

Lime  boil 54 . 0 

Sour  (HCl) 40.5 

Caustic  soda  boil 27 . 1 

Chemic 6.7 

Sour  (HCl) 16 .8 

Sour  (HCl). 5.8 

The  first  three  extracts  were  examined.  The  first  contained  3.7  per- 
cent of  nitrogen,  but  did  not  give  a  protein  reaction.  Treatment  with 
alcohol  precipitated  a  gelatinous  substance  resembling  Schunck's  pectic 
acid.  The  second  yielded  stearic  acid  and  a  small  proportion  of  cotton 
wax,  and  the  third,  which  contained  3.46  percent  of  nitrogen,  appeared 
to  consist  mainly  of  brown  coloring  matter. 

Higgins  "^  found  that  unsized  yarn  loses  about  one-third  of  its  protein 
on  steeping  in  salt  solution,  and  formed  the  opinion  that  the  usual  process 
of  scouring  with  caustic  soda  or  by  the  "  lime  sour  soda  wash  "  sequence 
removes  all  the  protein.  The  treatment  leaves  about  8  percent  of  the 
nitrogen  unaccounted  for,  and  it  is  suggested  that  this  residuum  must  be 
non-protein  nitrogen,  since  Hebden  ^  found  that  the  first  boil  effected  the 
removal  of  all  the  phosphorus  but  only  91.5  percent  of  the  nitrogen. 

1  Text.  Forschung,  1920,  p.  22.  '  j^^r.  Soc.  Dyers  &  Col,  1918,  p.  220. 

^Jour.  Soc.  Dyers  &  Col,  1908,  p.  106.         *  Jour.  Soc.  Dyers  &  Col,  1919,  p.  169. 

5  Jour.  Ind.  Eng.  Chem.,  1914,  p.  714. 


NITROGENOUS  MATTER  IN  COTTON  489 

The  total  loss  of  nitrogen  after  different  bleaching  processes  is  given  as 
follows:  First  boil,  91.5  percent;  second  boil,  91.7  percent;  chemic,  92.2 
percent;  sour,  92.7  percent. 

The  importance  of  the  complete  removal  of  the  nitrogenous  substances 
in  cotton  is  emphasised  by  Trotman  ^  who  has  found  that  nearly  all  cases 
of  bacterial  damage  to  finished  goods  are  associated  with  high  nitrogen 
content. 

1  Jour.  Soc.  Chem.  Ind.,  1909,  p.  1237. 


CHAPTER  XVI 
CELLULOSE  AND  ITS  CHEMICAL  PROPERTIES 

1.  Cellulose. — This  is  one  of  the  most  important  of  the  naturally 
occurring  chemical  compounds,  as  it  forms  the  basis  of  all  vegetable  tissue. 
Chemically  it  consists  of  carbon,  hydrogen,  and  oxygen,  and  has  the 
empirical  formula  CgHioOs. 

The  cellulose  of  all  vegetable  tissues,  even  in  a  highly  purified  condition, 
appears  to  contain  a  small  amount  of  mineral  constituents,  apparently 
forming  an  integral  or  organic  portion  of  the  fiber  structure.  The  amount 
of  ash,  for  instance,  obtained  from  bleached  cotton  is  about  0.1  to  0.4 
percent.  Even  "  Swedish  "  filter-paper,  which  has  been  treated  with 
hydrochloric  and  hydrofluoric  acids  for  the  removal  of  inorganic  constitu- 
ents, will  still  contain  from  0.03  to  0.05  percent  of  ash. 

Cellulose  belongs  to  a  class  of  bodies  known  as  carbohydrates,  and  is 
closely  related  to  the  starches,  dextrines,  and  sugars.  Chemicall}^  con- 
sidered, these  compounds  must  all  be  regarded  as  alcohols  containing 
aldehydic  and  ketonic  groups. 

Though  cellulose  appears  to  be  somewhat  analogous  to  these  bodies, 
it  nevertheless  differs  from  them  in  its  much  greater  resistance  to  the 
hydrolytic  action  of  acids,  alkalies,  and  enzymes.  The  latter  reagents 
readil}'  split  up  the  starches  into  simpler  bodies;  but  no  such  reaction, 
through  artificial  means  at  least,  has  been  observed  in  the  case  of  cellulose. 
That  such  a  reaction,  however,  takes  place  in  the  tissues  of  the  growing 
plant  there  is  no  doubt. 

The  word  "  cellulose  "  must  not  be  taken  as  signifying  a  simple  definite 
substance  of  unvarying  properties,  but  rather  as  a  generic  term  including 
quite  a  number  of  bodies  of  similar  chemical  nature.  Like  starch  and 
other  complex  carbohydrates  of  organic  physical  structure,  cellulose  will 
vary  somewhat  in  its  properties,  depending  upon  its  source  or  derivation. 
As  a  class  the  celluloses  exhibit  certain  chemical  characteristics,  by  means 
of  which  they  may  be  distinguished  from  associated  bodies  of  allied  chemical 
constitution.  Physically  they  are  colorless  amorphous  substances  capable 
of  withstanding  rather  high  temperatures  without  decomposition.  They 
are  insoluble  in  nearly  all  of  the  usual  solvents,  such  as  water,  alcohol, 
ether,  etc.,  but  dissolve  more  or  less  completely  in  an  ammoniacal  solution 

490 


CELLULOSE  491 

of  copper  oxide  (Schweitzer's  reagent)^  and  in  solutions  of  zinc  chloride 
and  phosphoric  acid.  Deming  -  states  that  cellulose  (in  the  form  of  filter- 
paper)  is  also  soluble  in  concentrated  aqueous  solutions  of  antimony 
trichloride,  stannous  chloride,  and  zinc  bromide.  Solution  in  these 
reagents  apparently  takes  place  without  decomposition,  as  the  cellulose 
may  be  precipitated  unchanged  therefrom  by  the  addition  of  acids  and 
various  salts,  the  precipitate  being  known  as  "  regenerated  "  cellulose. 
Cross  and  Bevan  attribute  the  solution  of  cellulose  in  cuprammonium  to 
the  preliminary  formation  of  a  soluble  gelatinous  hydrate  induced  by  the 
presence  of  the  copper.  That  the  alteration  in  the  cellulose  is  merely 
structural  has  been  disputed,  by  reason  of  the  fact  that  filaments  prepared 
from  the  precipitated  cellulose  have  a  gi-eatl}'  increased  affinitj''  for  dye- 
stuffs;  they  appear  to  act  more  as  a  hydrocellulose. 

Cross  and  Bevan  make  the  following  remarks  respecting  the  preparation 
of  the  ammonical  solution  of  copper  oxide :  The  solutions  of  cuprammonium 
compounds  generalh',  in  the  presence  of  excess  of  ammonia,  attack  cellulose 
rapidlj'  in  the  cold,  forming  a  series  of  gelatinous  hydrates,  passing  ulti- 
mately into  fully  soluble  forms.  The  solutions  of  the  pure  cuprammonium 
hydroxide  are  more  active  in  producing  these  effects  than  the  solutions 
resulting  from  the  decomposition  of  a  copper  salt  with  excess  of  ammonia. 
Two  methods  are  in  common  use  for  the  preparation  of  these  solutions, 
which  should  contain  10  to  15  percent  of  ammonia  and  2  to  2.5  percent  of 
copper  as  the  oxide.  (1)  Hj'drated  copper  oxide  is  prepared  bj'  precipitat- 
ing a  solution  of  copper  sulfate  of  2  percent  strength  with  a  shght  excess 
of  a  dilute  solution  of  sodium  hydrate.  The  precipitate  is  washed  until 
it  is  entirely  free  from  alkali.  The  original  solution  in  which  the  solution 
takes  place,  as  well  as  the  water  used  in  washing,  should  contain  a  small 
quantity  of  gh'cerol.  The  washed  precipitate  is  well  drained,  and  then 
mixed  with  a  quantity  of  a  10  percent  solution  of  glycerol,  in  contact 
with  which  it  may  be  preserved  unchanged  in  stoppered  bottles.  When 
desired  for  use,  the  oxide  is  washed  free  from  glycerol  and  dissolved  in 
ammonia  water  (of  15  to  20  percent  strength).  (2)  ]\IetaUic  copper,  in 
the  form  of  sheet  or  turnings,  is  placed  in  a  cylinder  and  covered  with  strong 
ammonia;  atmospheric  air  is  caused  to  bubble  through  the  column  of 
liquid  at  a  rate  calculated  to  40  times  the  volume  of  the  hquid  used  per 
hour.  In  about  six  hours  a  liquid  of  the  requisite  composition  is  obtained. 
Solutions  containing  5  to  10  percent  of  cellulose  are  readily  prepared  by 
digestion  in  the  cold  w^th  10  to  20  times  the  weight  of  cuprammonium 
solution,  a  rather  ropy  or  gelatinous  solution  being  obtained.  The  cellu- 
lose is  readily  precipitated  from  the  solution:    (a)  By  the  addition  of 

1  According  to  Cross  and  Bevan,  the  solubility  of  cellulose  in  avnmoniacal  copper 
oxide  was  first  discovered  and  described  by  John  Mercer. 
^Jour.  Amer.  Chem.  Soc,  1911,  p.  1515. 


492  CELLULOSE   AND   ITS   CHEMICAL  PROPERTIES 

neutral  dehydrating  agents,  such  as  alcohol,  sodium  chloride,  and  other 
salts  of  the  alkalies,  and  (b)  by  the  addition  of  acids,  in  which  case  the 
cellulose  is  precipitated  in  the  pure  state,  or  free  from'  copper  oxide. 

Cellulose  undergoes  change  very  readily,  the  chief  modifications  being 
(a)  hydration,  now  regarded  as  an  absorption  phenomenon  of  the  colloid 
cellulose,  (6)  oxidation,  (c)  acid  hydrolysis,  and  (d)  "  depolymerisation.* 
The  first  modification  is  roughly  estimated  by  means  of  the  absorptive 
power  of  the  material,  under  empirical  conditions,  for  iodine,^  substantive 
dyes,  cupric  hydroxide  from  Fehling's  solution  or  sodium  hydroxide. 
Another  approximate  method  for  ascertaining  the  extent  to  which  cellulose 
is  "  modified  "  is  to  determine  its  solubihty  in  sodium  hydroxide. 
Schwalbe  -  used  a  5  percent  and  Jentgen  ^  a  17.5  percent  solution.  The 
process  is  employed  mainly  in  distinguishing  various  types  of  artificial 
silks.  The  most  important  clues  to  ''  modification  "  are  afforded,  however, 
by  determining  (a)  the  "  copper  number  " — that  is,  the  number  of  grams 
of  copper  reduced  from  Fehling's  solution  by  100  grams  of  the  cellulose,  the 
value  being  below  1  for  purest  bleached  cotton  and  rising  to  as  much  as 
16  in  the  case  of  oxidised  cellulose,  and  (b)  the  viscosity  in  ammoniacal 
cupric  hydroxide  solutions.  The  latter  method  has  been  investigated  very 
thoroughly  in  the  Research  Department,  Woolwich  Arsenal,'^  where  it 
proved  successful  after  it  was  recognised  that  bright  light  and  air  must 
be  excluded  from  the  solution,  that  the  cuprammonium  solution  must  be 
fairly  constant,  and  that  the  "  falling  sphere  "  viscometer  is  the  most 
convenient  measuring  instrument.  It  is  found  that  cotton  treated  with 
alkali  hydroxides  gives  much  less  viscous  solutions  in  "  cuprammonium  " 
than  untreated  cotton,  and  that  the  viscosity  of  nitrated  cotton  (in  mix- 
tures of  alcohol  and  ether)  varies  according  to  the  viscosity  of  solutions 
of  the  original  cotton.  Nitrated  raw  cotton  gives  the  most  viscous  solu- 
tions, which  fact  suggests  that  the  action  of  sodium  hydroxide  may  be  of 
the  nature  of  "  de polymerisation." 

2.  Preparation  of  Pure  Cellulose. — In  order  to  obtain  pure  cellulose  for 
chemical  purposes  it  is  customary  to  treat  cotton  successively  with  dilute 
caustic  alkali,  dilute  acid,  water,  alcohol,  and  ether.  Cross  and  Bevan 
recommend  the  following  procedure  in  the  isolation  of  pure  cellulose  in  the 
study  of  the  vegetable  fibers:  (a)  The  fibrous  raw  material  is  boiled  with 
a  dilute  (1  to  2  percent)  solution  of  caustic  soda,  and,  after  thorough 
washing,  is  (b)  exposed  in  the  moist  state  to  an  atmosphere  of  chlorine  gas; 
(c)  it  is  again  treated  with  boiling  alkali.  By  such  treatment  the  "  non- 
cellulose  "   constituents   of  most  vegetable   fibers  are   removed,   and   a 

'  Jour.  Soc.  Chem.  Ind.,  1908,  p.  105. 
^  Die  C hemic  der  Zellulose,  p.  636. 
■'  Kundoffe,  1911,  p.  165. 
'  Jour.  Chem.  Soc,  1920,  pp.  473-78. 


CHEMICAL  CONSTITUTION  OF  CELLULOSE  493 

residue  of  pure  cellulose  is  obtained.  A  subsequent  slight  treatment  with 
a  dilute  solution  of  chloride  of  lime  for  the  removal  of  traces  of  coloring 
matters,  and  a  final  washing  with  alcohol  and  ether  completes  the 
purification. 

The  result  of  this  treatment  is  to  remove  all  foreign  and  encrusting 
materials  from  the  raw  fiber,  and  possibly  also  to  remove  the  thin,  external 
cuticular  membrane  which  may  be  chemically  different  from  the  rest  of  the 
tissue.  The  specific  gravity  or  density  of  cellulose  as  obtained  in  the 
usual  manner  is  about  1.5,  and  this  also  represents  the  density  of  cotton 
and  most  other  plant  fibers. 

Beltzer  describes  the  following  method  for  the  preparation  of  normal 
pure  cellulose  from  cotton:  (a)  The  cotton  is  first  carefully  combed  in 
order  to  remove  mechanically  all  dirt  and  foreign  matter;  (6)  it  is  then 
boiled  for  six  to  eight  hours  in  a  solution  of  caustic  soda  of  2^°  Tw.  The 
liquor  is  then  squeezed  out  and  the  cotton  rinsed  until  the  wash-water  is 
no  longer  colored;  (c)  the  cotton  is  next  treated  with  a  solution  of  hydro- 
chloric acid  of  2°  Tw,  and  at  120°  F.  for  three  to  four  hours;  then  washed 
in  warm  water;  (d)  the  fiber  is  then  bleached  in  a  solution  of  sodium 
hypochlorite  at  2°  Tw.  at  a  temperature  of  80°  F.  for  six  to  eight  hours, 
after  which  it  is  rinsed  in  lukewarm  water  and  squeezed;  (e)  a  second 
treatment  with  acid  is  then  given  similar  to  the  first,  and  the  cotton  is 
again  well  rinsed;  (/)  the  cotton  is  finally  treated  with  a  solution  of 
sodium  bisulfite  of  2°  Tw.  at  120°  F.  for  five  hours,  then  well  rinsed  in 
lukewarm  distilled  water.  The  cotton  is  then  squeezed  and  dried  at  a 
moderate  temperature.  The  analysis  of  this  dried  cellulose  should  corre- 
spond to  CeHioOs,  and  the  ash  on  ignition  should  not  exceed  0.05  percent. 
This  cellulose  should  not  contain  either  hydrocellulose  or  oxycellulose,  the 
presence  of  which  may  be  detected  by  sensitive  qualitative  tests.  This 
normal  pure  cellulose  should  be  very  resistant  to  the  action  of  caustic 
alkalies;  after  prolonged  treatment  with  boiling  dilute  caustic  soda  solu- 
tion, followed  by  washing,  acidulation,  and  rinsing  the  weight  of  the 
cellulose  should  remain  constant.  Any  loss  will  indicate  partial  solution 
due  to  presence  of  hydrocellulose  or  oxycellulose,  both  of  which  are  soluble 
in  caustic  soda.  To  remove  these  impurities  the  cotton  should  be  again 
boiled  with  a  solution  of  caustic  soda  of  2°  Tw.,  rinsed  in  distilled  water, 
aciduated  at  120°  F.,  with  a  solution  of  hydrofluoric  acid  of  1^°  Tw., 
washed,  treated  with  bisulfite,  finally  thoroughly  rinsed,  squeezed,  and 
dried  again.  On  distillation  with  hydrochloric  acid  this  purified  cellulose 
should  not  give  any  furfural,  nor  give  a  rose  color  with  phloroglucinol- 
hydrochloric  acid  reagent,  and  its  copper  index  with  Fehling's  solution 
should  be  zero  or  nearly  so. 

3,  Chemical  Constitution  of  Cellulose. — Chemically  considered,  cellu- 
lose is  a  derivative  of  the  open-chain  or  paraffin  series  of  hydrocarbons. 


494  CELLULOSE   AND   ITS   CHEMICAL  PROPERTIES 

and  furthermore  it  exhibits  the  reactions  of  a  saturated  compound.  As 
with  the  other  carbohydrates,  chemists  have  found  it  a  matter  of  great 
difficulty  to  ascertain  even  approximately  the  true  molecular  formula  of 
cellulose.  Though  its  empirical  formula  is  CeHioOs,  this  in  no  way 
represents  the  true  molecular  complexity  of  the  substance.  From  a 
study,  however,  of  its  various  synthetical  derivatives,  with  special  reference 
to  its  esters,  such  as  the  acetates,  benzoates,  and  nitrates,  the  provisional 
formula  of  C12H20O10  has  been  given  to  the  cellulose  molecule.  The  nature 
and  position  of  the  various  organic  groups  present  in  this  molecular  formula, 
however,  have  yet  to  be  explained. 

The  fact  that  cellulose  can  exist  in  the  colloidal  condition,  and  is 
difficultly  soluble  is  not  considered  as  indicating,  as  previously  supposed, 
a  high  molecular  weight,  for  both  alumina  and  silicic  acid  exist  in  the 
colloidal  state  and  it  is  not  necessary  to  assume  a  high  molecular  weight 
for  these  bodies. 

There  has  been  a  considerable  amount  of  speculation  among  chemists 
as  to  the  chemical  nature  and  constitution  of  cellulose,  but  there  has  been 
so  few  experimental  data  on  which  to  frame  an  intelligent  theory,  that 
most  of  these  speculations  are  mere  scientific  guesswork,  and  have  little 
more  than  a  provisional  value.  From  the  action  of  zinc  chloride  on 
cellulose  it  has  been  presumed  that  the  cellulose  molecule  contains  hydroxyl 
groups  of  such  a  nature  as  to  give  it  a  saltlike  property,  and  the  solution 
of  the  cellulose  in  the  zinc  chloride  is  supposed  to  be  due  to  the  formation 
of  a  kind  of  double  salt.  There  also  appears  to  be  a  chemical  reaction 
of  limited  degree  between  cellulose  and  dilute  solutions  of  caustic  alkalies 
and  mineral  acids.  According  to  IVIills,  the  relative  molecular  ratio  of 
the  absorption  by  cellulose  of  alkalies  and  acids  is  represented  by 
lONaOH  :  3HC1.  From  this  and  other  considerations,  it  would  appear 
that  cellulose  exhibits  the  properties  of  a  feeble  acid  and  of  a  still  more 
feeble  base. 

Vignon  has  proposed  to  give  cellulose  the  following  constitutional 
formula : 

O CHs 

0        N(CH0H)3. 

I     / 
CH2-CH/ 


This  is  based  on  a  study  of  the  highest  nitrate  of  cellulose  and  the 
decomposition  of  the  nitrate  by  alkalies  with  formation  of  hydroxy  pyruvic 
acid.  The  structure  given,  however,  is  more  or  less  hypothetical  in 
nature,  and  needs  experimental  confirmation  in  many  particulars  before 


CHEMICAL  CONSTITUTION  OF  CELLULOSE  495 

it  can  bo  accepted  without  question.  The  older  chemical  configuration 
of  cellulose  given  by  Bowman, 

H  H    H 

I  I       I 
H— C— C=C=C— C— C— H, 

II  III 
OH  OH       OH  OH  OH 

is  without  any  experimental  reason  for  its  existence,  and  the  idea  that 
it  contains  an  unsaturated  carbon  grouping,  — C=C — ,  has  been  proved 
erroneous.  From  a  study  of  the  osazones  of  oxycellulose,  Vignon  has 
ascribed  to  this  latter  body  a  constitutional  formula  having  the  group, 
in  union  with  varying  proportions  of  residual  cellulose, 

/COH 
(CH0H)3< 

\CH— CO, 


O 

The  existence  of  a  compound  containing  cellulose  and  sulfuric  acid  in 
the  proportion  4C6H10O5  :  H2SO4  is  put  forward  as  a  proof  that  in  its 
reactions  cellulose  behaves  like  a  complex  molecule  of  at  least  24  carbon 
atoms. 

Green,  however,  believes  the  simple  formula  CeHioOs  as  amply  justified. 
He  considers  the  adoption  of  C12H20O10  as  the  proper  formula,  based  on  the 
existence  of  tri-  and  pentanitrates,  as  erroneous,  and  considers  the  existence 
of  such  nitrates  as  very  doubtful.  He  proposes  the  following  constitutional 
formula  for  cellulose: 

CH  (OH)— CH— CH— OH 

I         >> 

CH(OH)— CH— CH2 

and  claims  that  such  a  formula  exhibits  the  aldehydic  nature  of  cellulose 
as  follows: 

— CH— OH 

> 

— CH2 

which  by  fixation  of  water  becomes: 

— CH(0H)2 

— CH2(0H) 
and  then : 

— CHO 

— CH2(0H) 


496 


CELLULOSE   AND   ITS   CHEMICAL  PROPERTIES 


This  formula  is  also  in  accord  with  the  formation  of  trinitro  and  triacetyl 
derivatives  as  the  limits  of  esterification  of  cellulose,  for  higher  derivatives 
could  only  be  obtained  by  the  transformation  of  the  two  central  oxygen 
atoms  into  two  hydroxyl  groups.  It  also  explains  why  cellulose  does  not 
react  with  either  phenylhydrazine  or  hydroxylamine,  as  it  does  not  contain 
carbonyl  (CO)  groups,  either  ketonic  or  aldohydic;  while,  on  the  other 
hand,  by  simple  hydrolysis  it  yields  derivatives  containing  the  carbonyl 
group.  Green  considers  the  existence  of  a  tetracetate  of  cellulose  as  doubt- 
ful, but  even  if  such  does  exist,  its  formation  is  probably  due  to  a  hydrolysis 
which  precedes  the  acetjlisation.  According  to  Fenton,  when  cellulose  is 
treated  with  dry  hydrochloric  acid  gas  without  heating,  there  is  formed 
chlormethyl-f  urf  ural : 

CH=C— CHO 

I     > 

CH=C— CH2— CI. 

Green  claims  that  his  formula  explains  this  remarkable  reaction. 
By  hydration  there  is  first  formed  the  intermediate  compound : 

CH=C— CH(OH) 

I     » 

CH=C— CHo 
which  gives  by  addition  of  hydrochloric  acid : 

CH=C— CH(0H)2 

I     > 

CH=C— CH2CI 

and  by  elimination  of  water: 

CH=C— CHO 

I     > 

CH=C— CH2-CI 

The  intermediate  product  assumed  by  Green  in  the  Fenton  reaction, 
appears  to  have  the  same  empirical  formula  as  lignin,  CeHoOs,  a  sub- 
stance associated  with  cellulose  in  woody  fiber.  This  would  seem  to 
furnish  a  physiological  explanation  of  the  relation  which  exists  between 
lignin  and  cellulose.  The  color  reactions  observed  by  Fenton  with  his 
new  derivatives  would  also  seem  to  demonstrate  this. 

Recent  work  in  the  constitution  of  cellulose  indicates  that  the  generally 
accepted  formula  for  starch,  cellulose,  etc.  (CgHioOs)^,  is  incorrect,  and 
should  be  replaced  by  (C6Hio05)n-H20.^ 

1  See  H.  Kiliani,  Chem.  Zeit.,  1908,  p.  366. 


CHEMICAL  CONSTITUTION  OF  CELLULOSE  497 

Green  states  that  a  successful  formula  for  cellulose  must  explain  the 
following  facts:  (1)  A  trinitrated  derivative;  (2)  a  triacctyl  derivative; 
(3)  with  concentrated  caustic  soda  cellulose  gives  a  compound  which  is 
decomposed  by  water  to  form  cellulose  hydrate  (mercerising),  which  is 
much  more  soluble  than  cellulose  itself  in  solutions  of  ammoniacal  copper 
oxide  and  zinc  chlorides;  (4)  treated  with  carbon  disulfide  the  alkali 
cellulose  is  converted  into  cellulose  thiocarbonate  (viscose),  which  is 
easily  soluble  in  water;  (5)  cellulose  does  not  react  with  phenylhydrazine 
or  hydroxylamine ;  (6)  as  an  ultimate  product  of  hydrolysis  (with  sulfuric 
acid)  cellulose  gives  glucose;  (7)  Fenton's  reaction  or  the  formation  of 
chlormethyl-f urf ural ;  (8)  the  formation  of  oxycellulose  by  the  oxidation 
of  cellulose;  this  body  has  properties  very  similar  to  cellulose  itself,  but 
has  a  decided  acid  character,  and  when  distilled  with  dilute  sulfuric  acid 
it  gives  furfural;  (9)  when  oxycellulose  is  boiled  with  milk  of  lime  it  gives 
dioxybutyric  acid  and  iso-glucosic  acid  (Faber  and  Follens) : 

CH(OH)  — CH— CO  •  OH 

> 

CH(OH)-     CH— COOH 

(10)  nitrocelluloses,  when  treated  with  dilute  caustic  soda,  give  oxypyruvic 
acid  (Will):   CH2(0H)C0C0-0H.i 

Regarded  from  the  point  of  view  of  the  ionic  theory,  cellulose  is  con- 
sidered as  a  molecular  aggregate  consisting  of  a  mixture  of  ions  of  varying 
dimensions.  Hence,  cellulose  as  a  typical  colloid  has  no  definite  reactive 
unit  as  a  body  which  takes  the  crystalline  form,  nor  a  fixed  molecular 
constitution  which  may  be  represented  in  the  limits  of  a  constitutional 
formula;  for  the  cellulose  molecule  cannot  be  regarded  as  a  static  unit, 
but  rather  as  a  dynamic  equilibrium;  its  reacting  unit  at  any  time  being 
a  function  of  the  conditions  surrounding  it.  This  view  of  the  constitution 
of  cellulose  has  been  advanced  by  C.  F.  Cross. 

1  Many  chemists  by  studying  various  compounds  of  cellulose  have  suggested  a 
number  of  different  molecular  formulas  for  this  compound.  Cross  and  Bevan  in 
studying  the  cellulose  xant hates  arrive  at  rather  simpler  formula  than  Green.  Eder 
{Berichte,  1880,  p.  169)  adopted  the  formula  (C6Hio05)2  for  cellulose,  from  the  fact 
that  he  obtained  four  different  nitration  steps  between  mono-  and  trinitrocellulose. 
Vieille  {Comptes  rendus,  1882,  p.  132)  observed  eight  intermediate  nitration  steps,  and 
consequently  adopted  the  formula  (C6Hio06)4,  and  this  was  also  accepted  bj^  Lunge  and 
Bebie  (Zeit.  ang.  Chem.,  1901,  p.  507).  Mendelejeff  (MoniL  Sri.,  1897,  p.  510)  adopted 
the  formula  (CeHioOs)?  on  a  basis  of  his  analyses  of  various  nitrated  celluloses.  Bumcke 
and  Wolffenstein  (Berichte,  1899,  p.  2493)  arrived  at  the  formula  (C6Hi(,06)i2  through 
a  study  of  the  action  of  hydrogen  peroxide  on  cellulose  leading  to  the  formation  of  a 
compound  they  called  "hydralcellulose."  Tollens  {Kohlenhydrate,  vol.  1,  p.  231) 
adopted  the  formula  (C6Hio06)3o,  while  Skraup  (see  Piest,  Die  ZeUuIose,  p.  137)  pro- 
posed the  formula  (CeH  1005)34. 


498  CELLULOSE   AND   ITS   CHEMICAL  PROPERTIES 

4.  Chemical  Reactions  of  Cellulose. — In  its  chemical  reactions  cellu- 
lose is  particularly  inert,  combining  with  only  a  few  substances,  and  then 
only  with  great  difficulty  and  under  peculiar  conditions.  It  is  quite 
resistant  to  the  processes  of  oxidation  and  reduction,  and  hydrolysis  and 
dehydration.  This  high  degree  of  resistance  to  hydrolysis  (alkaline)  and 
oxidation  belongs  only  to  cotton  cellulose  and  to  the  group  of  which  it  is 
the  type,  and  which  includes  the  cellulose  of  flax,  ramie,  and  hemp.  A 
large  number  of  celluloses,  on  the  other  hand,  are  distinguished  by  con- 
siderable reactivity,  due  to  the  presence  of  "  free  "  carbonyl  groups,  and 
are  therefore  more  or  less  easily  hydrolysed  and  oxidised.  The  hydra- 
tion of  cellulose  is  a  common  occurrence  in  the  manufacture  of  paper, 
being  brought  about  by  a  prolonged  beating  of  the  fiber  in  the  engine, 
with  the  result  that  the  fibers  become  quite  gelatinous  and  the  resulting 
sheet  of  paper  is  more  or  less  transparent.  This  process  is  used  in  the 
manufacture  of  imitation  parchment  paper  and  grease-proof  paper.  The 
sheet  is  highly  transparent  and  when  heated  with  a  lighted  match  under- 
neath it  becomes  blistered.  The  celluloses  of  the  cereal  straws  and 
esparto  grass  are  of  this  type,  hence  the  relative  inferiority  of  the  papers 
into  the  composition  of  which  they  enter.  Cotton  cellulose  is  also 
distinguished  by  the  fact  that  it  gives  no  furfural  when  distilled  with  acid, 
and  by  being  precipitated  unchanged  from  its  solution  in  alkaline  carbon 
disulfide.  Concentrated  sulfuric  acid  dissolves  cellulose  with  the  pro- 
duction of  a  viscous  solution;  dilution  with  water  causes  the  precipita- 
tion of  an  amorphous  substance  known  as  amyloid,  a  starch-like  body 
having  the  formula  C12H22O11,  and  hke  starch  it  is  colored  blue  with 
iodine.  On  this  reaction  is  based  the  method  of  testing  for  cellulose,  by 
applying  sulfuric  acid  and  iodine.  On  boiling  with  dilute  sulfuric  acid, 
cellulose  is  converted  into  dextrin  and  glucose.  In  the  hydrolysis  of  cellu- 
lose, as  for  instance  by  boiling  with  dilute  sulfuric  acid,  it  is  converted  into 
a  carbohj^drate  having  the  composition  C6H12O6,  in  accordance  with  the 
following  equation : 

C6Hio05  +  H20  =  C6Hi206 

On  heating  with  acetic  anhydride  to  180°  C,  cellulose  is  converted  into 
an  acetyl  derivative  having  the  formula  Ci2Hi404(OCOCH3)6.  Cellu- 
lose does  not  react  directly  with  acetic  anhydride,  but  at  the  temperature 
above  given  and  with  six  times  its  weight  of  the  anhydride  it  gives  the 
derivative  having  the  above  formula,  and  which  may  be  called  the  tri- 
acetate. With  a  smaller  quantity  of  acetic  anhydride,  a  mixture  of  lower 
acetates  is  obtained  which  are  insoluble  in  glacial  acetic  acid.  The 
triacetate  is  readily  soluble  in  this  acid,  however,  and  also  in  nitrobenzene. 
Its  solutions  are  very  viscous.     Regenerated  cellulose,  prepared  by  pre- 


HYDROCELLULOSE  499 

cipitation  of  \'iscous  solutions,  reacts  with  acetic  anhydride  directly,  and 
gives  what  appears  to  be  the  tetracetate.^ 

6.  Hydrocelliilose. — By  the  moderated  action  of  concentrated  acids 
and  various  acid  salts,  cellulose  appears  to  undergo  a  process  of  hydrol- 
ysis, being  converted  into  a  friable  amorphous  body  known  as  hydro- 
cellulose.-  This  reaction  is  of  importance  in  the  carbonising  process  for 
removing  vegetable  matter  from  woolen  goods;^ 

Hydrocellulose  appears  to  be  a  combination  of  cellulose  with  one 
molecule  of  water,  and  has  been  given  the  formula  C12H22O11.  The 
formation  of  hj^drocellulose  from  cotton  results  in  structural  disinte- 
gration so  that  the  fiber  may  easily  be  reduced  to  a  powder. 

When  an}'  cellulose  fiber  is  exposed  to  the  action  of  dilute  acids  under 
ceitain  conditions,  its  tenacity  is  destroyed,  and  it  falls  to  a  powder  which 
is  presumably  h^'dro cellulose.  ^Tien  the  above  reaction  takes  place, 
however,  instead  of  a  gain  in  weight  as  theory  would  indicate,  there  is 
invariable'  a  loss  and  a  small  amount  of  soluble  matter  is  formed,  a  portion 
of  which  in  all  probabihty  is  c?-glucose.^  The  elementary-  composition  of 
the  powder  is  also  sho^Ti  to  be  identical  with  that  of  cellulose,  the  previous 
statements  on  this  point  being  claimed  to  be  founded  on  faulty  experi- 
mental methods.  A  hj-drated  cellulose  is  not  formed  under  these  condi- 
tions, but  a  hj'drolysis  takes  place  similar  to  that  undergone  by  other 
carbohj'drates  imder  comparable  conditions. 

Hydrocellulose  is  also  of  considerable  technical  importance,  as  it  is 
much  more  reactive  than  ordinary  cellulose,  and  so  is  employed  for  the 
production  of  the  nitric  and  acetic  acid  compounds  of  cellulose,  as  the 
hydrocellulose  compounds  are  much  more  soluble  in  the  solvents  employed. 

Hydrocellulose  is  also  manufactured  for  the  purpose  of  making  gun- 
cotton,  being  used  in  place  of  cotton;  for  when  treated  with  the  necessarj' 
acid  mixture  it  furnishes  a  more  sensitive  guncotton  which  explodes  more 
rapidly  and  therefore  is  better  adapted  for  the  making  of  detonating 
fuses. 

Hydrocellulose  may  be  prepared  by  treating  a  mixtiu-e  of  cotton  and 
potassium  chlorate  with  hydrochloric  acid  at  a  temperature  of  60°-70°  C.'^ 

1  For  further  remarks  concerning  the  acetylation  of  cellulose  see  Cross  and  Bevan, 
Cellulose  and  Researches  on  Cellulose. 

'  Girard,  in  1875,  was  probabh'  the  first  to  investigate  hydrocellulose.  He  prepared 
it  both  by  steeping  cotton  for  twelve  hours  in  sulfuric  acid  of  45°  Be.,  and  bj-  impreg- 
nating cotton  with  3  percent  sulfuric  acid  solution,  then  drjTng  and  heating. 

'  Carbonising  as  a  technical  process  was  apparently  first  introduced  by  Kober  in 
Canstatt  in  1852  for  the  recovery  of  wool  from  wool-cotton  rags.  Later  on,  Frezon 
and  Isart  took  out  patents  in  France  and  England  for  the  carbonising  of  raw  wool 
to  remove  vegetable  matter  and  burrs. 

*  See  Stern,  Jour.  Chem.  Soc,  1904,  p.  336. 

*  Stahmer's  method.     Oxj'cellulose  is  also  hkeh'  to  be  produced  in  this  reaction. 


500  CELLULOSE  AND  ITS  CHEMICAL  PROPERTIES 

The  product  obtained  in  this  manner  is  in  the  form  of  a  white 
powder  and  is  very  resistant  to  further  hydrolysis  by  acids  and 
alkahes. 

Hydrocelhilose  may  also  be  prepared  in  the  following  manner :  Chlorine 
gas  is  passed  into  glacial  acetic  acid  until  the  solution  is  perceptibly  yellow. 
Then  5  parts  of  this  acid  mixture  is  heated  to  60°-70°  C,  and  thoroughly 
mixed  with  1  part  of  cotton.  In  a  short  time  the  cotton  swells  up  con- 
siderably and  becomes  viscous.  The  heating  is  continued  until  a  sample 
is  found  to  be  completely  miscible  with  water.  The  product  is  then 
washed  until  neutral  and  then  dried. 

Hydrocellulose  is  to  be  distinguished  from  cellulose  in  that  it  is  colored 
blue  by  a  solution  of  zinc  chlor-iodide  or  with  a  solution  of  iodine  in 
potassium  iodide.  Hydrocellulose  also  reduces  Fehling's  solution  and 
an  ammoniacal  solution  of  silver  nitrate,  due  to  the  presence  of  free 
carbonyl  groups  in  the  molecule. 

Justin-Mueller  states  that  between  the  temperatures  of  130°  C.  and 
140°  C,  hydrocellulose  begins  to  turn  yellow  and  form  caramel,  while 
oxycellulose  scarcely  turns  yellow  at  145°  C.  to  150°  C,  and  cellulose 
itself  only  begins  to  turn  yellow  at  a  temperature  of  180°  C.  This 
reaction  may  therefore  be  employed  as  a  characterisation  of  hydro- 
cellulose even  in  the  presence  of  oxycellulose  and  cellulose. 

Hydrocellulose  is  not  to  be  confused  with  hydra  cellulose.  The  latter 
contains  only  water  of  hydration,  whereas  the  former  is  a  hydrolysed 
product  of  cellulose  intermediate  between  normal  cellulose  and  com- 
pletely hydrolysed  cellulose  (sugar). 

Hydrocellulose  is  characterised  by  its  reducing  power  and  its  solu- 
bility in  caustic  soda  solution.  Like  cellulose  itself,  hydrocellulose 
exhibits  great  affinity  for  water,  giving  hydrates  of  hydrocellulose.  The 
extent  of  the  hydration  of  hydrocellulose  is  determined  by  the  degree 
of  hydrolysis;  that  is  to  say,  the  more  hydroxyl  groups  (OH)  a  cellulose 
contains,  the  more  water  it  will  combine  with. 

There  is  considerable  difference  in  hydration  and  hydrolysis  in  the 
case  of  cellulose;  while  cotton  may  be  converted  apparently  into  a 
hydrated  cellulose  without  structural  disintegration,  where  it  is  converted 
into  hydrocellulose  (by  the  action  of  dilute  acids)  the  structure  and  con- 
sequently the  strength  of  the  fiber  is  destroyed.  Both  hj'dration  and 
hydrolysis,  however,  under  certain  conditions  may  occur  simultaneously. 
The  hydrated  celluloses  (of  which  there  may  be  many  varying  in  degree 
of  hydration)  are  characterised  by  high  hygroscopic  moisture,  whereas  the 
hydrocelluloses  are  abnormally  low  in  this  respect.  Hydrated  celluloses, 
where  the  original  structure  of  the  fiber  is  retained  (mercerised  cotton), 
have  high  tensile  strength,  but  in  hydrated  celluloses  of  an  amorphous 
character  (the  artificial  silks)  the  tensile  strength  is  low.     All  hydrated 


HYDROCELLULOSE  501 

celluloses  are  characterised  by  a  diminished  resistance  to  hydrolysis  by 
acids  to  an  extent  proportional  to  their  "  degree  of  hydration." 

If  hydrocellulose  (prepared  according  to  Girard)  is  boiled  with  dilute 
caustic  soda  the  insoluble  residue  loses  its  reducing  properties  and  shows 
all  the  properties  of  unchanged  cellulose.  It  follows  from  this  fact, 
in  all  probability,  that  hydrocellulose  consists  of  at  least  two  materials, 
unchanged  cellulose  and  soluble  degradation  products.  This  view  of  the 
non-homogeneity  of  hydrocellulose  has  been  confirmed  by  Netthofel,^ 
and  by  Hauser  and  Herzfeld.^  Netthofel  shows  that  it  is  also  possible 
to  separate  the  two  parts  of  hj'drocellulose  by  boiling  with  Fehling's 
solution;  if  tlte  cuprous  oxide  precipitated  on  the  cellulose  by  this  treat- 
ment be  dissolved  in  acid  and  the  residue  carefully  washed,  pure  cellulose 
remains.  He  also  showed  by  careful  microscopic  study  the  complex 
nature  of  hydrocellulose  and  that  its  largest  part  still  consists  of  unchanged 
cellulose. 

By  far  the  most  important  reactions  of  hydrocellulose  are  those  of  the 
degraded  part,  that  is,  ultimately,  of  dextrose. 

(1)  So  far  as  reducing  power  is  concerned,  this  is  clear  without  further  comment. 
If  the  alkali-soluble  part  is  removed  by  boiling  with  caustic  soda,  the  reducing  power 
disappears  at  the  same  time. 

(2)  It  is  further  asserted  of  hydrocellulose  that  it  decomposes  hydriodic  acid  with 
liberation  of  iodine.  This  phenomenon  is  explained  without  trouble  by  the  presence 
of  sugar-hke  degradation  products. 

(3)  In  the  same  way  the  explanation  is  to  be  found  of  the  yellow  coloration  of 
hydrocellulose  on  heating  with  dilute  alkalies:  sugar-Uke  substances  show  this  yellow 
coloration. 

(4)  Hydrocellulose  gives  a  good  yield  of  acetic  acid  when  heated  under  pressure 
with  alkalies.  However,  both  cellulose  and  sugar-like  substances  give  acetic  acid 
under  this  treatment,  cellulose  in  considerable  amounts,  on  which  account  the  acetic 
acid  from  hydrocellulose  may  come  for  the  most  part  from  the  unchanged  cellulose, 
and  for  the  rest  from  the  degradation  products  containing  sugar. 

(5)  On  oxidation  hydrocellulose  gives,  beside  acetic  acid,  saccharic  acid  and  oxalic 
acid.  Of  these  two,  oxalic  acid  also  results  from  the  oxidation  of  cellulose.  The 
appearance  of  saccharic  acid  may  be  explained  by  the  presence  of  sugar-like  decom 
position  products  in  the  hydrocellulose. 

(6)  The  same  ex-planation  must  be  claimed  for  the  presence  of  isosaccharic  acid  which 
Tollens  obtained  when  he  cooked  hydrocellulose  with  milk  of  lime. 

(7)  The  fact  that  hydrocellulose  contains  one  molecule  of  chemically  combined 
water  has  previously  been  regarded  as  highly  characteristic  of  hydrocellulose,  its 
empirical  formula  accordingly  being  C6H10O5H2O.  Some  time  ago  Schwalbe  and 
also  Ost  expressed  the  opinion  that  this  water  content  of  hydrocellluose  should  be 
confirmed. 

Since  it  was  unlikely  from  previous  knowledge  of  the  nature  of  hj'drocellulose  that 
this  view  is  correct,  we  must  again  consider  Netthofel's  explanation  of  the  supposed 
water  content: 

^  Dissertation,  Berlin,  1914. 
^Chem.Zeit.,  1915,  p.  QS9. 


502  CELLULOSE  AND  ITS  CHEMICAL  PROPERTIES 

We  have  in  hydrocellulose  a  mixture  of  unchanged  cellulose  and  sugar-like  degra- 
dation products,  that  is,  of  CeHioOs  and  C6H12O6.  Accordingly  the  percentage  of 
oxygen  and  hydrogen  in  such  a  mixture  must  be  greater  than  in  pure  cellulose  with  the 
composition  CoHioOs.  From  this  a  molecule  of  chemically  combined  water  can  readily 
be  figured  out.  The  supposed  water  content  comes  therefore  from  the  sugar-like 
degradation  products. 

The  different  formulas  which  have  been  established  for  hydrocellulose  (by  Girard, 
Biittner  and  Nevmian,  and  others)  can  thus  be  ex-plained:  for  the  greater  the  amount 
of  sugar-like  degradation  products  in  the  hydrocellulose,  the  greater  will  be  the  "water 
content." 

So  far  as  the  other  properties  attributed  to  hydrocellulose  are  concerned,  namely 
its  increased  activity  toward  esterification,  hydrolysis  under  pressure,  etc.,  these  are 
not  peculiarities,  but  are  easily  e.xplained  on  the  ground  that  the  distorted,  disintegrated 
and  pulverised  fibers  offer  to  the  reagents  a  larger  surface  and  a  more  reactive  material 
than  the  long-fibered  cellulose. 

Finally,  the  peculiar  behavior  of  dyestuffs  toward  hydrocellulose  is  likewise  not  to 
be  regarded  as  characteristic,  because  here  there  are  numerous  contradictions  which 
cannot  be  explained,  since  it  could  never  be  proved  that  the  material  was  homogeneous. 

6.  Hydralcellulose. — This  is  a  product  described  by  Bumcke  and 
Wolffenstein  ^  and  prepared  by  the  action  of  hydrogen  peroxide  on  cotton 
cellulose.  It  is  not  a  product  of  oxidation,  but  one  of  hydrolysis  and  is 
made  by  steeping  cotton  in  a  strong  solution  of  hydrogen  peroxide  for  as 
long  as  ninety  days.  The  product  is  a  white  powder  which  shows  strong 
reducing  properties  towards  Fehling's  solution  and  also  with  an  ammoni- 
acal  silver  solution;  it  also  yields  a  yellowish-colored  hydrazone.  The 
body  is  apparently  an  aldehyde,  and  may  also  be  formed  as  an  intermediate 
step  in  the  preparation  of  oxycellulose.  When  boiled  with  ten  times  its 
quantity  of  a  10  percent  solution  of  caustic  soda,  hydralcellulose  is  con- 
verted for  the  most  part  into  cellulose  and  a  soluble  portion  which  is 
called  "  acid  cellulose."  These  reactions,  however,  need  further  confir- 
mation, as  there  is  still  some  doubt  as  to  the  identity  and  existence  of  these 
bodies. 

7.  The  Carbonising  Process  in  Relation  to  Cotton  and  Vegetable  Fibers. 
— In  the  carbonising  process  the  material  to  be  treated  is  impregnated 
with  a  boiling  solution  of  sulfuric  acid  of  2°  Be.,  squeezed,  dried,  and  then 
beaten  or  washed  thoroughly  to  remove  the  disintegrated  cotton  fibers 
or  other  vegetable  cellulose.  In  another  method  gaseous  hydrochloric 
acid  is  allowed  to  act  on  the  material  in  place  of  the  sulfuric  acid  solution. 
Solutions  of  certain  acidic  salts  such  as  magnesium  chloride  and  aluminium 
chloride  are  also  employed  for  carbonising.  These  salts  when  dried  into 
the  fiber  liberate  free  hydrochloric  acid  which  decomposes  the  vegetable 
matter.  With  magnesium  chloride  it  is  customary  to  use  a  solution  of 
9°  Be.,  and  with  aluminium  chloride  one  of  7°  Be.  the  material  being 
saturated  with  one  of  these  solutions  and  dried  at  a  temperature  of  about 

1  Berichte,  1899,  p.  2493. 


ACTION  OF  ZINC  CHLORIDE  ON  CELLULOSE  503 

300°  F.  After  this  the  material  is  well  washed.  The  choice  of  the  car- 
bonising agent  will  largely  depend  on  the  character  of  the  goods  to  be 
treated  and  the  nature  of  the  dyestuff  with  which  they  may  be  colored. 

The  carbonising  process  in  relation  to  cotton  and  related  cellulose, 
must  merely  be  considered  as  a  study  of  the  destructive  action  of  acids 
or  acid  substances  on  the  fiber.  As  the  cotton  is  completely  destroyed 
and  eliminated  in  the  process,  its  connection  with  carbonising  is  really  a 
negative  one.  The  detailed  study  of  the  carbonising  process  relates  more 
to  the  treatment  of  wool  and  shoddy,  and  consequently  the  reader  is 
referred  to  those  sections  for  a  fuller  consideration  of  this  process.  At  the 
present  point  it  has  been  endeavored  to  limit  the  discussion  solely  to  its 
relation  to  cotton.  It  may  be  well  to  point  out,  however,  that  the  term 
"  carbonising  of  wool  "  is  a  misnomer.  It  is  really  the  cotton  that  is 
"  carbonised  "  and  not  the  wool,  the  latter  being  left  in  a  practically 
uninjured  condition. 

8.  Action  of  Zinc  Chloride  on  Cellulose. — A  concentrated  solution 
of  zinc  chloride  will  dissolve  cellulose  on  heating  and  digesting  for  some 
time.  This  solution  has  been  employed  industrially  for  the  preparation 
of  cellulose  filaments,  which  are  subsequently  treated  with  hydrochloric 
acid  and  washed  for  the  purpose  of  removing  the  zinc  salt;  the  thread 
is  then  carbonised  and  is  employed  for  the  carbon  filament  of  incandescent 
electric  lamps. 

The  threads  for  the  production  of  the  carbon  filaments  are  prepared 
by  forcing  the  syrupy  solution  of  cellulose  through  fine  glass  orifices  into 
alcohol,  whereby  the  cellulose  is  precipitated  in  a  continuous  thread. 
The  filaments  obtained  from  this  source  are  more  homogeneous  in 
composition  and  possess  great  elasticity  and  a  very  uniform  electrical 
resistance.^ 

The  product  of  cellulose  with  zinc  chloride  has  also  received  several 
other  industrial  applications;  vulcanised  fiber  is  prepared  bj'-  treating 
paper  with  a  concentrated  solution  of  zinc  chloride,  and  the  resulting 
gelatinous  mass  is  manufactured  into  various  articles,  such  as  blocks, 
sheets,  etc.  One  part  of  paper  is  treated  with  four  parts  of  zinc  chloride 
solution  of  65°  to  75°  Be.,  until  the  fibers  are  partially  gelatinised,  when 
the  sheets  are  then  pressed  together  into  very  compact  masses.  The  chief 
difficult}^  encountered  is  the  subsequent  removal  of  the  zinc  salt,  which 
necessitates  a  very  lengthy  process  of  washing.  Vulcanised  fiber  is  quite 
hard,  having  the  consistencj^  of  horn ;  but  by  the  addition  of  deliquescent 
substances  such  as  glycerol  or  glucose  a  pliable  product  may  be  obtained. 
The  material  may  be  rendered  water-proof  by  a  further  process  of  nitra- 

1  The  introduction  ot  tungsten  metal  filaments  for  incandescent  lamps  during 
recent  years  has  now  almost  made  the  carbon  filament  lamp  obsolete,  as  the  tungsten 
filament  gives  a  much  higher  lighting  efficiency  for  the  same  strength  of  current. 


504  CELLULOSE  AND  ITS   CHEMICAL  PROPERTIES 

tion.  The  solution  has  also  been  suggested  for  use  as  a  thickening  agent 
in  calico-printing.  It  has  also  been  suggested  for  use  in  the  production 
of  lustra-cellulose  or  artificial  silk  but  has  not  met  with  any  success  in 
this  field. 

Cross  and  Bevan  recommend  the  following  method  for  preparing 
this  solution  of  cellulose:  4  to  6  parts  of  anhydrous  zinc  chloride  are  dis- 
solved in  6  to  10  parts  of  water,  and  1  part  of  bleached  cotton  is  then  stirred 
in  until  evenly  moistened.  The  mixture  is  digested  for  a  time  at  60° 
to  80°  C,  when  the  cellulose  is  gelatinised;  the  solution  is  completed  by 
heating  on  a  water-bath  and  stirring  from  time  to  time,  and  replacing 
the  water  which  evaporates.  In  this  manner  a  homogeneous  syrup  is 
obtained.  This  solution  of  cellulose  is  entirely  decomposed  by  dilution, 
the  cellulose  being  precipitated  as  a  hydrate  in  combination  with  zinc 
oxide.  On  washing  this  precipitate  with  hydrochloric  acid  a  pure  cellulose 
hydrate  is  obtained,  the  quantity  recovered  being  approximately  equal 
to  the  original  cellulose  taken.  When  precipitated  by  the  addition  of 
alcohol,  a  compound  of  cellulose  and  zinc  oxide  is  obtained,  with  18  to 
25  percent  of  ZnO,  and  having  the  approximate  molecular  ratio  of 
2C6H!o05  :  ZnO. 

According  to  Wynne  and  Powell  ^  the  addition  of  calcium  or  magnesium 
chloride  is  beneficial.  Dreaper  and  Tompkins  ^  recommend  the  use  of 
basic  zinc  chloride  and  calcium  chloride.  Fremery  and  Erban  ^  recommend 
that  the  cotton  cellulose  be  first  vigorously  treated  with  oxidising  agents 
previous  to  solution  in  the  zinc  chloride.  According  to  Bronnert  "*  the 
cellulose  may  be  dissolved  in  a  cold  solution  of  zinc  chloride  by  a  previous 
strong  hydration  of  the  cotton,  such  as  treatment  for  one  hour  with  a 
cold  concentrated  solution  of  caustic  soda.  It  is  claimed  that  in  this 
manner  a  solution  may  be  obtained  containing  80  percent  and  more  of 
cellulose.^  Zinc  chloride  dissolved  in  twice  its  weight  of  concentrated 
hydrochloric  acid  will  also  dissolve  cotton  without  heating.  The  cellu- 
lose is  not  much  changed  if  this  solution  is  rapidly  diluted,  but  on  long 
standing  the  cellulose  is  broken  down  to  water-soluble  dextrins.^ 

A  concentrated  solution  of  zinc  chloride  in  hydrochloric  acid  dissolves 
cellulose  quite  rapidly  and  in  the  cold.  This  latter  method  is  useful  in  the 
laboratory  for  the  study  of  celluloses,  but  as  yet  has  received  no  technical 
application. 

The  reagent  is  prepared  by  dissolving  one  part  of  zinc  chloride  in  twice 
its  weight  of  concentrated  hydrochloric  acid.     If  the  solution  of  cellulose 

^Eng.  Pat.  16,805  of  1884. 

2  Eng.  Pat.  17,901  of  1897  and  Ger.  Pat.  113,786. 

^Ger.  Pat.  111,313  and  Eng.  Pat.  6,557  of  1899. 

*  See  Siivern,  Die  Kunstliche  Seide,  p.  307. 

^  See  Ger.  Pat.  118,836  and  Eng.  Pat.  18,260  of  1899. 

^  See  Schwalbe,  Die  Chemie  die  Zellulose,  p.  155. 


ACTION  OF  ALKALIES  ON   CELLULOSE;    VISCOSE  505 

obtained  with  this  solvent  is  dihited  when  fresh,  the  cellulose  will  be 
precipitated  unaltered;  but  if  the  solution  is  allowed  to  stand,  the  cellu- 
lose is  rapidly  resolved  into  decomposition  products,  such  as  dextrin,  etc., 
which  are  entirely  soluble  in  water.  B}''  means  of  this  solution  it  has  been 
shown  that  the  cellulose  molecule  does  not  contain  any  unsaturated 
carbon  groups,  for  it  exhibits  no  absorption  of  bromine.  A  solution  of 
a  lignocellulose,  on  the  other  hand,  gives  a  marked  bromine  absorption, 
thus  showing  evidence  of  unsaturated  carbon  groups. 

Cellulose  is  colored  a  deep  violet  by  a  solution  of  zinc  chlor-iodide, 
and  this  reagent  is  employed  as  a  delicate  test  for  the  presence  of  cellulose. 
The  reagent  may  be  best  prepared  by  using  90  parts  of  a  concentrated 
solution  of  zinc  chloride,  adding  6  parts  of  potassium  iodide  in  10  parts 
of  water,  and  iodine  until  saturated. 

9.  Action  of  Alkalies  on  Cellulose;  Viscose. — When  cellulose  is  treated 
with  concentrated  caustic  alkalies,  it  undergoes  a  change  which  may 
be  crudely  referred  to  as  "  mercerisation,"  whereby  a  compound  known 
as  alkali-cellulose  is  formed,  in  which  the  molecular  ratio  of  alkali  to 
cellulose  may  be  given  as  Ci2H2oO]o  :  NaOH.  When  this  body  is  treated 
with  carbon  disulfide,  a  substance  known  as  cellulose  thiocarbonate 
01  xanthate  is  formed.  This  body  yields  a  very  viscous  solution  with 
water  and  has  been  utilised  for  various  technical  purposes  under  the 
name  of  viscose. 

For  the  preparation  of  viscose  it  is  best  to  employ  the  following  molec- 
ular proportions  of  the  reagents : 

CeHioOs  :  2NaOH  :  CS2  (with  30  to  40  H2O). 

The  reaction  is  carried  out  in  practice  by  treating  bleached  cotton 
(though  other  forms  of  cellulose,  such  as  purified  woodpulp,  may  also  be 
used)  with  excess  of  a  15  percent  solution  of  caustic  soda,  then  squeezing 
out  the  excess  of  liquor,  but  leaving  in  the  fiber  about  three  times  its 
weight  of  the  solution.  The  mass  is  then  mixed  with  about  50  percent 
(on  the  weight  of  the  cotton)  of  carbon  disulfide,  and  allowed  to  stand 
in  a  covered  vessel  for  about  three  hours  at  the  ordinary  temperature; 
after  which  sufficient  water  is  added  to  cover  the  mass,  and  the  hydration 
allowed  to  proceed  for  several  hours  longer.  The  mass  is  then  stirred  up 
and  a  homogeneous  solution  is  obtained  which  may  be  diluted  to  any 
desired  degree.  The  solution  thus  prepared  has  a  yellow  color,  which, 
however,  is  due  to  the  presence  of  various  thiocarbonates  which  occur 
as  by-products  in  the  reaction.  By  treating  the  solution  with  a  saturated 
solution  of  common  salt  or  with  alcohol,  pure  cellulose  thiocarbonate  is 
pr(>cipitated  as  greenisli  white  flocculent  mass,  which  may  be  redissolved 
in  water,  giving  a  colorless  or  faintly  yellow-colored  solution.     On  the 


506  CELLULOSE   AND   ITS   CHEMICAL   PROPERTIES 

addition  of  various  metallic  salts  to  this  solution,  the  corresponding 
xanthates  may  be  precipitated.  With  iodine  a  precipitate  of  dioxy- 
thiocarbonate  is  formed,  which  may  be  said  to  take  place  in  accordance 
with  the  following  equation  (X  representing  the  residue  of  the  cellulose 
molecule) : 

.OX        XOv  ,0X— XO. 

CS         +           CS+l2  =  2NaI+CS  CS. 

^SNa     NaS^  "^S S^ 

Cellulose  xanthate  undergoes  spontaneous  decomposition,  splitting 
up  into  cellulose  hydrate,  alkali,  and  carbon  disulfide;  this  cellulose 
hydrate  is  also  known  as  regenerated  cellulose.  When  this  decomposition 
takes  place  in  solutions  containing  more  than  1  percent  of  cellulose,  a  firm 
jelly  of  coagulated  cellulose  is  produced  of  the  same  volume  as  the  original 
solution.  A  solution  containing  as  much  as  10  percent  of  cellulose 
decomposes  to  a  substantial  solid  of  hydrated  cellulose  which  gives  up 
its  water  with  extreme  slowness.  The  cellulose  regenerated  in  this 
manner  is  probably  in  the  "  colloidal  "  form.  This  substance  can  also 
be  precipitated  from  the  xanthate  solution  by  the  addition  of  various 
salts,  such  as  ammonium  chloride. 

10.  Esters  of  Cellulose. — Alkali  cellulose  also  reacts  with  benzoyl 
chloride,  with  the  formation  of  cellulose  henzoate}  Another  ester  of  cellu- 
lose is  the  acetate,  which  can  be  made  by  the  action  of  acetic  anhydride  on 
cellulose  heated  in  a  sealed  tube — regenerated  cellulose  can  also  be 
employed.  Cross  ^  states  that  80  to  90  percent  of  acetyl  groups  may  be 
introduced  into  the  cellulose  molecule  without  apparently  changing  the 
original  properties  of  the  cellulose.  According  to  a  recent  patent^  an 
almost  theoretical  yield  of  cellulose  acetate  may  be  obtained  by  con- 
ducting the  acetylation  in  the  presence  of  methyl  sulfate;  the  process 
given  being  as  follows:  30  parts  of  cotton  are  treated  in  a  bath  with  70 
parts  of  acetic  anhydride,  120  parts  of  glacial  acetic  acid,  and  3  parts  of 
dimethyl  sulfate  until  solution  is  almost  complete.  The  solution  is  then 
filtered  and  the  filtrate  is  poured  into  a  large  quantity  of  water,  whereupon 
the  acetate  of  cellulose  is  precipitated. 

The  acetate  of  cellulose  may  be  prepared  by  heating  a  mixture  of 
hydrocellulose,  acetic  anhydride,  and  sulfuric  acid  to  60°-70°  C.  The 
acetate  of  cellulose  so  obtained  is  soluble  in  ether  and  chloroform  (Lederer). 
At  Sthamer's  chemical  works  (Hamburg)  acetate  of  cellulose  is  prepared 
by  heating  a  mixture  of  hydrocellulose,  acetic  acid,  acetyl  chloride,  and 

^  See  Cross  and  Bevan,  Cellulose,  p.  32,  and  Researches  on  Cellulose,  p.  34,  etc. 
"^Jour.  Soc.  Chem.  Ind.,  1904,  p.  297. 
»  Brit.  Pat.,  1905,  No.  9998. 


ESTERS  OF  CELLULOSE  507 

sulfuric  acid  to  65°-70°  C.  An  acetate  of  cellulose  soluble  in  alcohol 
and  pyridine  is  obtained  by  heating  a  mixture  of  cellulose,  acetic  anhy- 
dride, and  sulfuric  acid  to  45°  C.^  Miles  and  Pierce  obtain  it  by  heat- 
ing a  mixture  of  cellulose,  acetic  anhydride,  acetic  acid,  and  sulfuric  acid 
to  70°  C.  Landsberg  substitutes  phosphoric  acid  for  sulfuric  acid  in  the 
preceding  mixture.  Acetate  of  cellulose  has  also  been  prepared  by 
warming  a  mixture  of  cellulose,  acetic  acid,  acetic  anhydride,  and  a 
mixture  of  phenol-sodium  sulfonate  and  phenol-sulfonic  acid,  or  of  sodium 
naphtholate  and  naphthol-sulfonic  acid  (Little,  Walker  &  Mork).  Cellu- 
lose may  also  be  acetylised  by  means  of  a  mixture  in  nitrobenzene  solu- 
tion of  acetyl  chloride  and  chloride  of  zinc  or  magnesium,  in  the  presence 
of  pyridine  or  quinoline  (Wohl,  Charlottenburg). 

Cellulose  regenerated  from  viscose  esterifies  much  more  readily  with 
anhydrides  and  chlorides  of  acids  than  does  ordinary  cellulose.  The 
tetracetate  of  cellulose  in  particular  is  obtained  by  mixing  intimately 
hydrate  of  cellulose  with  a  concentrated  solution  of  magnesium  acetate, 
in  the  proportion  of  two  molecules  of  the  acetate  for  one  molecule  of 
cellulose.  To  this  mixture,  which  is  made  homogeneous  and  dried  at 
110°  C.  (230°  F.),  is  added  two  molecules  of  acetyl  chloride  for  each  molecule 
of  magnesium  acetate.  The  action  of  acetyl  chloride  must  proceed 
progressively  and  with  caution,  so  as  to  prevent  the  temperature  rising 
above  30°  C.  (86°  F.).  The  product  is  afterward  treated  with  water  to 
remove  the  magnesium  salts ;  it  is  then  dried  and  exposed  to  the  action  of  a 
solvent  to  separate  the  cellulose  acetate  from  the  small  quantity  of  uncom- 
bined  cellulose.  This  solution  is  clarified  and  filtered,  and  then  is  evapo- 
rated, the  residue  being  the  ester  in  a  pure  state.  The  product  thus 
obtained — tetracetate  of  cellulose — resembles  very  closely  nitrocellulose, 
but  it  is  distinguished  from  it  by  not  being  explosive;  indeed,  it  is  not 
even  very  combustible.  It  dissolves  in  chloroform,  methyl  alcohol, 
epichlorhydrin,  ethyl  benzoate,  glacial  acetic  acid,  nitrobenzene,  etc. 

These  solutions  furnish  films  of  perfect  transparency  and  absolute 
continuity  even  when  they  are  so  thin  as  to  produce  interference  color 
effects.  They  are  impermeable  to  water,  and  offer  great  resistance  toward 
the  action  of  reagents.  For  saponification  they  must  be  boiled  for  several 
hours  with  an  alcoholic  solution  of  caustic  soda;  but  even  then  disintegra- 
tion does  not  take  place,  and  the  film  preserves  not  only  its  form,  but  also 
its  transparency. 

By  varying  the  conditions  of  treatment  a  number  of  different  acetates 
have  been  prepared.-     The  tetracetate  has  received  a  number  of  com- 

^  Farbenfabriken  vorms.  Fr.  Bayer  &  Co.  of  Elberfeld. 

^  Ost  {Zeit.  angew.  C hemic,  1919,  pp.  66,  76  and  82)  has  studied  quite  extensively 
the  formation  of  cellulose  acetates.  The  triacetate  Ls  formed  by  the  action  of  acetic 
anhydride  and  zinc  chloride,  the  other  acetates,  especially  those  formed  with  sulfuric 


508  CELLULOSE   AND  ITS   CHEMICAL   PROPERTIES 

mercial  applications  for  the  production  of  films  and  for  waterproofing.^ 
By  the  action  of  nitric  acid  under  varying  conditions,  a  number  of  cellu- 
lose mtrates  (improperly  called  nitrocelluloses)  have  been  prepared  which 
have  received  numerous  applications  (see  pyroxylin)?  Concentrated 
sulfuric  acid  reacts  with  cellulose  to  form  at  first  a  cellulose  sulfate;  this 
subsequently  undergoes  decomposition  with  a  consequent  hydrolysis  of 
the  cellulose  molecule  and  the  formation  of  amyloid.  Aceto-sulfates  of 
cellulose  have  been  prepared  by  the  joint  action  of  acetic  acid,  acetic 
anhydride,  and  sulfuric  acid  on  cellulose.^ 

For  the  preparation  of  what  Cross  and  Be  van  term  the  normal  cellu- 
lose aceto-sulfate,  to  which  the  formula  4(C6H702)  •  (SO4)  •  (C2H302)io 
is  ascribed,  16  grams  of  dry  cotton  are  stirred  for  twenty  minutes  at  30°  C. 
in  100  cc.  of  a  mixture  of  equal  parts  of  glacial  acetic  acid  and  acetic 
anhydride  containing  4.5  percent  by  weight  of  sulfuric  acid.  After 
standing  for  one  hour,  a  homogeneous,  translucent,  and  viscous  solution 
is  obtained,  which  is  precipitated  on  being  poured  into  water  as  a  semi- 
translucent  gelatinous  hydrate,  which  is  soluble  in  alcohol.  By  using 
less  sulfuric  acid  the  product  obtained  is  insoluble  in  alcohol. 

11.  Action  of  Metallic  Salts. — Although  cellulose  is  comparatively 
inert  to  the  majority'  of  chemical  reagents,  it  has  a  powerful  attraction  for 
certain  salts  held  in  solution  and  will  absorb  them  completely.  This 
power  of  absorption  is  especially  marked  toward  salts  of  vanadium,  these 
l)eing  completely  separated  from  solutions  containing  only  one  part  of 
the  salt  per  trillion. 

12.  Compound  Celluloses. — Besides  cellulose  itself,  there  are  a  number 
of  derived  substances  which  are  known  as  compound  celluloses.  These  are 
classified  into  three  general  groups : 

(a)  Pedocelluloses,  related  to  pectin  compounds  of  vegetable  tissues;  represented 
among  the  fibers  by  raw  flax;  resolved  by  hydrolysis  with  alkalies  into  pectic  acid 
and  cellulose.  The  pectocelluloses  are  somewhat  richer  in  oxygen  than  normal  cellulose 
(cotton)  When  boiled  with  dilute  alkalies  they  are  easily  resolved  into  cellulose,  the 
pectin  substances  being  converted  into  soluble  derivatives.  This  is  the  reaction  that 
takes  place  in  the  bleaching  of  linen. 

(b)  Lignocelluloses,  forming  the  main  constituent  of  woody  tissue  and  represented 
among  the  fibers  by  jute;  resolved  by  chlorination  into  chlorinated  derivatives  of 
aromatic  compounds  soluble  in  alkalies  and  cellulose.  Lignocellulose  consists  of  about 
75  percent  cellulose  and  25  percent  of  lignin.     Jute  absorbs  iodine,  forming  an  unstable 

acid  as  the  catalyst,  all  show  a  degradation  of  the  cellulose  to  a  cellulose  dextrin,  and 
the  existence  of  a  real  tetracetate  is  very  doubtful,  sulfoacetates  and  other  products 
being  formed. 

-  Noyes  (Kiinslofe,  1914,  pp.  207  and  227)  has  studied  the  formation  of  formic  acid 
esters  of  cellulose,  but  formylation  is  more  difficult  than  acetylation  or  nitration. 

'  For  0  thorough  and  detailed  description  of  the  cellulose  nitrates  and  the  industries 
leased  thereon,  consult  VVorden,  Nttrocellulose  Industry,  2  vols.,  1911. 

2  See  Cross,  Lk'van  &  Briggs,  Benchte,  1905,  p   1859. 


COMPOUND  CELLULOSES  509 

compound.  This  reaction  is  employed  in  the  quantitative  determination  of  ligno- 
celluloses  in  combination  with  other  forms  of  cellulose.  Lignocelluloses  also  hydrolyse 
much  more  readily  than  normal  cellulose. 

(c)  Adipncelluloses,  forming  the  epidermis  or  cuticular  tissue  of  fibers,  leaves,  cork, 
bark,  etc.;  resolved  by  oxidation  with  nitric  acid  into  derivatives  similar  to  those  of 
the  oxidation  of  fats  and  cellulose.  The  adipocelluloses  are  cellular  rather  than  fibrous 
in  structure.     They  contain  more  carbon  and  less  oxygen  than  normal  cellulose. 

Fremy  groups  the  various  celluloses  and  their  derived  bodies  in  the 
following  manner,  which  is  based  on  a  chemical  classification :  (a)  celluloses, 
including  normal  cellulose,  paracellulose,  and  metacellulose ;  (6)  vasculose 
(identical  with  hgnocellulose) ;    (c)  cutose;   (d)  jpectose} 

^  The  subject  of  cellulose  and  its  derivatives  is  a  very  extensive  one  and  its  detailed 
industrial  chemistry  is  beyond  the  province  of  the  present  volume,  which  endeavors 
to  limit  the  consideration  of  this  subject  to  the  bearing  it  may  have  on  the  textUe 
fibers.  For  further  studies  on  the  subject  of  cellulose  the  reader  is  referred  to  the 
exhaustive  treatises  of  Cross  and  Bevan,  Schwalbe,  Beltzer,  Worden,  etc.,  as  given 
in  the  bibliography  at  the  end  of  the  volume. 


CHAPTER  XVII 


CHEMICAL  PROPERTIES  OF  COTTON 


1.  Action  of  Heat. — Cotton  itself  presents  the  same  general  reactions 
and  chemical  properties  as  cellulose.  It  is  capable  of  standing  rather 
high  temperatures  without  decomposition  or  alteration;  though  it  appears 
that  when  cotton  is  subjected  to  a  temperature  of  160°  C,  whether  moist 
or  dry  heat,  a  dehydration  of  the  cellulose  takes  place,  accompanied  by 
a  structural  disintegration  of  the  fiber.  This  fact  has  an  important 
bearing  on  the  singeing,  calendering,  and  other  finishing  processes  where 
high  temperatures  are  used. 

Within  the  limits  of  the  temperatures  to  be  met  with  in  the  usual 
processes  of  drying,  a  dry  heat  has  little  or  no  influence  on  the  substance 
of  the  cotton  fiber.  At  250°  C.  cotton  begins  to  turn  brown;  and  when 
ignited  in  the  air  it  burns  freely,  emitting  an  odor  faintly  suggesting 
acrolein,  but  without  the  characteristically  empyreumatic  odor  of  burning 
animal  fibers. 

When  cotton  yarn  is  dried  for  twelve  hours  at  70°  C.  (160°  F.)  it  loses 
about  5  percent  in  tensile  strength,  and  also  much  of  its  elasticity,  becoming 
harsh  and  brittle.  It  rapidly  regains  its  hygroscopic  moisture,  however,  on 
exposm-e  to  the  air  and  recovers  its  original  strength.  Heated  from 
90°  to  100°  C.  (195°  to  212°  F.)  cotton  loses  about  6  to  8  percent  in  weight; 
from  100°  to  120°  C.  about  0.5  percent  more.  Above  120°  C.  the  loss  is 
very  slow,  and  indicates  decomposition;  at  180°  C.  (360°  F.)  it  will  have 
lost  about  1  percent  more  in  weight,  and  the  fiber  begins  to  acquire  a 
yellowish  color  showing  the  beginning  of  carbonisation. 

When  subjected  to  dry  distillation  cotton  is  decomposed  into  methane, 
ethane,  water,  methyl  alcohol,  acetone,  acetic  acid,  carbon,  dioxide, 
pyrocatechol,  etc. 

The  following  table  gives  the  results  of  the  dry  distillation  of  cotton 
(Ramsay  and  Chorley)  •} 


Distillate. 

Raw  Cotton, 
Percent. 

Bleached  Cotton, 
Percent. 

Cotton  Cellulose 

from  Viscose, 

Percent. 

Solids  and  carbon 

33 
46 
11 
10 

34.44 
51.11 

7.77 
6.68 

42.0 

Liquids 

Carbon  dioxide 

44.0 
7.4 

Other  gases 

6.6 

'Jou 

r.  Soc.  Chein.  Ind. 
510 

1892,  p.  872. 

ACTION  OF  WATER 


511 


The  composition  of  the  liquid  distillate  per  100  parts  of  cotton  is  as 
follows : 


Substance. 

Raw  Cotton, 
Percent. 

Bleached  Cotton, 
Percent. 

Cotton  Cellulose 

from  Viscose, 

Percent. 

Acetic  acid 

1.31 

7.07 
12.00 

2.11 
10.24 
13.33 

2.00 

Methyl  alcohol 

10.24 

Tars 

13.33 

The  composition  of  the  gaseous  distillate  is  as  follows: 


Substance- 


Carbon  dioxide 

Oxygen 

Residual  gases . 


Raw  Cotton. 
Percent. 


76.90 

3.66 

19.44 


Bleached  Cotton, 
Percent. 


54.14 

8.50 

37.36 


Cotton  Cellulose 

from  Viscose, 

Percent. 


80 

4 

16 


2.  Action  of  Light. — It  is  a  well-known  fact  that  when  cotton  fabrics 
are  long  exposed  to  the  action  of  light,  and  especially  direct  sunlight,  a 
gradual  deterioration  is  the  result.  Witz  ^  showed  that  oxycellulose  was 
formed  from  cotton  in  the  presence  of  air  and  moisture;  Girard,  however, 
claims  that  in  this  case  it  was  more  probable  that  hydrocellulose  was 
formed.  Witz  also  exposed  a  cotton  fabric  during  an  entire  summer 
under  conditions  in  which  air  and  moisture  were  excluded  and  only  light 
was  the  active  agent.  He  found  the  formation  of  oxycellulose  on  cloth 
exposed  to  blue  rays  but  none  on  cloth  exposed  to  yellow  or  red  rays. 
Doree  and  Dyer  -  made  an  investigation  on  the  action  of  ultra-violet  light 
on  the  strength  and  durability  of  cotton  fabrics,  and  found  that  oxycellulose 
was  formed  rather  rapidly.  It  is  no  doubt  the  violet  and  ultra-violet 
rays  in  sunlight  that  cause  the  destructive  action  of  light  on  cotton 
cellulose, 

3.  Action  of  Water. — Cotton  is  unaltered  and  insoluble  in  cold  and 
boiling  water.  Treatment  in  boiling  water  for  twelve  hours  appears  to 
increase  the  dyeing  effect  of  cotton  for  substantive  dyes  and  to  decrease 
it  for  basic  dyes.^     This  is  probably  due  to  a  partial  hydration  of  the 

1  Bull.  Soc.  Ind.  Rouen,  1883,  p.  190. 
^Jour.  Soc.  Dxjers  &  Col.,  1917,  p.  17. 
^  Hiibner  and  Pope,  Jour.  Soc.  Chem.  Ind.,  1904,  p.  404. 


512  CHEMICAL   PROPERTIES   OF   COTTON 

cotton  cellulose,  causing  a  slight  change  in  chemical  properties  without 
alteration  in  physical  form  or  structure.  When  cotton  is  heated  for  eight 
hours  under  pressure  at  150°  C.  (300°  F.,  corresponding  to  4.75  atmos- 
pheres) it  is  not  apparently  affected.  By  the  action  of  boiling  water  or 
steam,  however,  cotton  undergoes  certain  physical  modifications;  it  be- 
comes plastic,  somewhat  after  the  manner  of  wool,  but  to  a  less  degree. 
On  this  property  are  based  some  important  effects  in  finishing,  as  in 
calendering,  the  production  of  silk  finish,  beetling,  and  many  others. 
At  160°  C.  (320°  F.,  corresponding  to  6.15  atmospheres  pressure),  however, 
the  fiber  appears  to  undergo  some  alteration.  If  air  is  also  present  the 
effect  is  very  pronounced  at  170°  C.  (340°  F.,  corresponding  to  7.85  atmos- 
pheres pressure).  Hydrocellulose  is  apparently  formed  when  cotton  is 
heated  with  water  under  a  pressure  of  20  atmospheres.  When  cotton  is 
subjected  to  the  action  of  steam  under  high  pressures  the  fiber  undergoes 
disintegration,  the  effect,  no  doubt,  of  hydrolytic  action.  A  considerable 
rise  in  temperature  is  noted  when  cotton  is  wetted  with  water.  This 
effect,  however,  does  not  appear  to  be  due  to  chemical  action,  as  the 
same  effect  is  obtained  on  wetting  finely  divided  inert  solids.  Masson  ^ 
has  made  a  detailed  study  of  the  conditions  which  give  rise  to  these 
phenomena.  Martini  -  also  gives  a  study  of  this  effect.  According  to 
Masson  the  action  is  due  to  a  distillation  effect,  whereas  Martini  con- 
siders that  the  liquids  are  absorbed  by  the  solids,  passing  into  the  solid 
state  themselves.^ 

Cotton  becomes  yellow  when  exposed  to  steam,  and  it  has  actually 
been  proposed  to  impart  to  white  cotton  the  appearance  of  Egyptian 
varieties  by  steaming  under  1  to  1.5  atmospheres  pressure  for  twenty-five 
to  thirty  seconds.*  The  yellowing  is  not  due  to  the  fatty  constituents  of 
the  cotton,  and,  in  fact,  F.  Erban  has  found  that  the  phenomenon  is 
intensified  if  the  fat  has  been  extracted. °  The  "  gums  "  in  the  cotton  may 
contribute  to  the  process  but,  on  the  whole,  fully  scoured  cotton  is  as  liable 
to  become  yellow  as  raw  cotton.  The  subject  has  been  studied  by  Frei- 
berger,^  who  came  to  the  following  conclusions:  (a)  Bleached  fabrics 
show  the  strongest  discoloration,  those  bleached  cold  being  more  susceptible 
than  fabrics  bleached  warm;  (h)  fabrics  bleached  warm  with  sodium 
hypochlorite  containing  an  excess  of  sodium  carbonate  are  less  subject  to 
yellowing;  (c)  oxycellulose  becomes  quite  one  hundred  times  as  dark  as 
cellulose  on  steaming,  but  hydrocellulose  is  less  affected  than  cellulose. 

1  Proc.  Roy.  Soc,  vol.  74,  p.  230. 

2  Phil.  Mag.,  vol.  47,  p.  329. 

3  8ee  also  Phil.  Mag.,  vol.  50,  p.  618. 
"  Text.  Mer.,  1914,  Feb. 

5  Fdrber-Zeit.,  1912,  p.  370. 

e  Fdrher-Zeit.,  1917,  pp.  221,  235,  249. 


ACTION  OF   WATER 


513 


The  main  cause  of  the  yellowing  of  cotton  on  steaming  is  therefore  the 
presence  of  oxy cellulose. 

Scheurer  ^  has  made  a  study  of  the  action  of  prolonged  steaming  on 
cotton  fabrics.  He  used  both  gray  cloth  and  cloth  which  had  been  boiled- 
out  for  bleaching,  and  steamed  the  samples  at  a  temperature  of  99°  to 
100°  C.  for  varying  periods  of  time  with  the  following  results  as  to  tensile 
strength : 


Original  cloth 

Steamed  60  hours 
120  " 
180  " 
240  " 
300  " 
360  " 
420  " 
480  " 
540  " 


Gray  Cloth. 


Warp. 


100 
82 
72 
60 
51 
39 
31 
27 
21 
21 


Filling. 


100 
76 
49 
40 
37 
32 
30 
19 
19 
13 


Boiled-out. 


Warp. 


100 
83 
70 
59 
53 
47 
41 
31 
20 
14 


Filling. 


100 
90 
69 
58 
50 
34 
34 
25 
19 
17 


It  would  seem,  therefore,  that  the  gray  and  the  white  pieces  are  affected 
in  about  the  same  way  by  the  steaming.  As  the  steam  is  always  charged 
with  a  certain  amount  of  air,  the  effect  is  really  due  to  the  joint  action  of 
steam,  temperature,  and  air.  In  tests  on  the  comparison  of  steaming 
of  wool  and  cotton  it  was  found  that  four  hundred  and  twenty  hours  of 
steaming  tendered  cotton  75  percent  and  sixty  hours  of  steaming  tendered 
wool  75  percent;  therefore,  it  was  concluded  that  the  resistance  of  cotton 
to  steaming  is  about  seven  times  greater  than  that  of  wool. 

The  action  of  frost  or  ice  on  cotton  has  been  investigated  by  Roth  well.  ^ 
Two  pieces  of  bleached  cloth,  one  of  good  quality  and  one  of  poor  quality, 
were  placed  in  water  for  ten  minutes,  then  taken  out  and,  without  squeez- 
ing, hung  up  in  a  freezing  atmosphere.  The  cloth  became  quite  stiff  in 
three  minutes,  and  though  the  temperature  never  increased  beyond  3°  C. 
for  three  hours,  the  ice  had  completely  evaporated  at  the  end  of  that  time, 
leaving  the  cloth  perfectly  dry.  On  testing  along  with  the  original  cloth 
no  loss  in  strength  was  observed.  Even  after  repeating  the  freezing 
operation  four  times  the  strength  of  both  qualities  of  cloth  was  found  to  be 

'Bull.Soc.  Ind.  Mulh.,  1893. 

^Jour,  Soc.  Dxjers  &  Col,  1892,  p.  153. 


514 


CHEMICAL  PROPERTIES  OF  COTTON 


equal  to  the  original.     From  this  it  is  evident  that  cloth  frozen  in  full  open 
width  is  not  tendered. 

The  following  table  shows  the  effect  of  moisture  on  the  strength  and 
elasticity  of  cotton  and  linen  yarns/  the  figures  being  the  average  of  twenty 
tests  in  each  case : 


Material. 


20's  cotton  yarn,  gray 

20's  cotton  yarn,  bleached 

40's  cotton  yarn,  gray  (American) 

40's  cotton  yarn,  gray  (Egyptian) 

40/2  cotton  yarn,  gray  (hard  twist) .... 
40/2  cotton  yarn,  bleached  (hard  twist) 

2.5's  carded  flax  tow  yarn,  gray 

25 's  card  flax  tow  yarn,  bleached 

30's  flax  line  yarn,  gray 

30's  flax  line  yarn,  bleached 


Strength,  Ounces. 


Dry. 


25.5 
24.7 
9.1 
11.2 
24.2 
25.6 
54.2 
26.1 
75.2 
54.0 


Moist. 


28.1 
24.8 
10.6 
11.3 
27.3 
23.3 
63.3 
46.2 
75.7 
60.0 


Elasticity,  Percent. 


Dry. 


3.1 

3.7 
2.4 
2.5 
2.4 
3.9 
0.8 
0.7 
0.9 
1.0 


Moist. 


3.9 
4.2 
2.9 
3.1 
3.6 
3.1 
1.4 
1.4 
1.4 
1.4 


4.  Action  of  Cuprammonium  Solution. — Like  cellulose  itself,  cotton  is 
dissolved  by  Schweitzer's  reagent,  though  under  ordinary  conditions  its 
solution  is  a  rather  slow  process.  In  order  to  dissolve  cotton  most  effect- 
ively in  ammoniacal  copper  oxide,  it  is  recommended  to  treat  the  raw 
cotton  with  a  strong  solution  of  caustic  soda  until  the  fibers  swell  up  and 
become  translucent;  squeeze  out  the  excess  of  liquid,  and  wash  the  cotton 
with  strong  ammonia  water;  then  treat  with  the  solution  of  ammoniacal 
copper  oxide  and  the  cotton  will  be  found  to  dissolve  quite  rapidly.  This 
solution  may  furthermore  be  filtered  and  diluted  with  water.  The  use  of 
this  solution  for  the  production  of  artificial  silk  filaments  is  now  practiced 
on  a  large  commercial  scale.  It  is  also  used  for  the  preparation  of  artificial 
fabrics,  such  as  lace  and  tulle.  This  reaction  is  also  utilised  in  the  prepara- 
tion of  a  fabric  known  as  Willesden  canvas;  the  cotton  fabric  is  passed 
through  a  solution  of  ammoniacal  copper  oxide,  whereby  the  surface  be- 
comes coated  with  a  film  of  gelatinised  cellulose  containing  a  considerable 
amount  of  copper  oxide.  On  subsequent  hot  pressing  this  film  is  fixed  on 
the  surface  of  the  material  as  a  substantial  coating,  which  is  said  to  make 
the  canvas  waterproof  and  render  it  unaffected  by  mildew  and  insects. 

If  the  solution  of  cotton  in  the  cuprammonium  reagent  is  exposed  to 
the  light  for  some  time,  a  precipitate  of  cellulose  and  copper  hydrated 
oxide  will  form.     If  the  latter  is  dissolved  away  with  hydrochloric  acid 

1  Oester.  Wall.  u.  Leinen-Ind. 


ACTION   OF   AOTDR  515 

the  cellulose  is  left  in  the  form  of  needlelike  crystals  (Gilson) ;  but  accord- 
ing to  Schwalbe,  cotton  cellulose  has  never  yet  been  noticed  in  this  form, 
as  all  recent  observations  show  it  to  exist  in  the  colloidal  form. 

5.  Action  of  Acids. — With  mineral  acids  cotton  exhibits  practically  the 
same  general  reactions  as  pure  cellulose.  Concentrated  sulfuric  acid 
produces  amyloid  in  the  manner  previously  mentioned,  and  this  fact  is 
utihsed  in  the  preparation  of  what  is  known  as  vegetable  parchment. 
Unsized  paper  is  rapidly  passed  through  concentrated  sulfuric  acid,  then 
thoroughly  washed  and  dried.  The  effect  of  this  treatment  is  to  cause 
the  formation  on  the  surface  of  the  paper  of  a  layer  of  gelatinous  amyloid, 
which  on  subsequent  pressing  and  drying  gives  a  tough  membranous  sur- 
face to  the  paper  resembling  true  parchment.  This  renders  the  paper 
grease-proof  and  water-proof,  and  increases  its  tensile  strength 
considerably. 

Mercer  (in  1844)  appears  to  have  been  the  first  to  discover  the  effect  of 
concentrated  sulfuric  acid  on  cotton;  in  fact  this  reaction  was  developed  at 
the  same  time  as  that  of  strong  solutions  of  caustic  soda  on  cotton.  Mercer 
pointed  out  that  the  action  of  the  concentrated  sulfuric  acid  was  very 
similar  in  its  effect  to  that  of  the  strong  alkali  in  that  the  fiber  swelled 
somewhat,  and  the  cotton  showed  an  increase  in  strength  and  an  increased 
affinity  for  many  dyes.  The  action  of  the  strong  acid  must  be  very  brief, 
otherwise  the  cotton  will  be  dissolved  with  the  formation  of  sulfuric  acid 
esters.  This  matter  will  be  further  discussed  under  the  subject  of 
mercerisation. 

Artificial  horse-hair  has  been  prepared  in  a  similar  manner  from  certain 
Mexican  grasses.  These  latter  are  steeped  for  a  short  time  in  concentrated 
sulfuric  acid,  and  become  parchmentised  thereby,  so  that  on  being  sub- 
sequently washed  and  combed  they  assume  an  appearance  very  much 
resembling  horse-hair,  and  are  said  to  possess  even  greater  elasticity  than 
horse-hair  itself.  In  place  of  strong  sulfuric  acid  a  solution  of  zinc  chloride 
may  be  used  with  similar  results.  Amyloid  appears  also  to  be  a  product 
of  natural  plant  growth,  as  its  presence  has  been  detected  in  the  walls  of 
vegetable  cells;  it  may  be  recognised  by  giving  a  blue  color  with  iodine. 
The  parchmentising  action  of  strong  sulfuric  acid  on  cotton  has  become  a 
very  important  commercial  process  in  connection  with  mercerising  for 
the  production  of  a  permanent  stiff  finish  on  the  fabric.  Its  consideration 
will  be  taken  up  under  the  subject  of  mercerising. 

Under  proper  conditions  of  treatment  concentrated  mineral  acids  have 
a  mercerising  or  hydrating  action  on  cotton.  Sulfuric  acid  at  the  ordinary 
temperature  begins  to  exert  a  mercerising  effect  at  a  strength  of  35°  Be. 
Acid  of  49°  to  55°  Be.  acts  much  in  the  same  manner  as  caustic  soda;  the 
fiber  becomes  mercerised  and  possesses  an  increased  affinity  for  dyestuffs, 
and  acquires  an  increased  luster  and  strength.     The  same  is  also  true  of 


516  CHEMTCAL   PROPERTIES   OF   COTTON 

concentrated  solutions  of  phosphoric  acid  (59°  Be.).  If  the  action,  how- 
ever, of  the  acids  is  at  all  prolonged,  complete  hydrolysis  and  destruction 
of  the  fiber  take  place.  By  the  prolonged  action  of  concentrated  sulfuric 
acid  (over  50  percent)  on  cotton,  the  fiber  is  dissolved  with  the  formation 
of  a  sulfuric  acid  ester  of  cellulose.  Langhaus  ^  describes  this  method  for 
the  preparation  of  artificial  silk.  He  also  describes  the  solution  of  cotton 
in  phospho-sulfuric  acid.^  Neither  of  these  processes,  however,  seem 
to  have  met  with  any  commercial  success. 

Very  dilute  solutions  of  sulfuric  acid  especially  in  the  cold,  have  no 
appreciable  action  on  cotton.  But  if  the  fiber  is  impregnated  with  such  a 
solution  and  then  allowed  to  dry  it  becomes  tendered;  this  is  owing  to 
the  gradual  concentration  of  the  acid  on  drying,  and  hydrolysis  of  the 
fiber.  According  to  Bowman,  the  acid  acts  as  a  catalytic  agent,  piobably 
forming  at  first  an  unstable  compound  with  the  cellulose  which  is  decom- 
posed by  water  and  air  into  hydrocellulose,  thus  liberating  the  acid  agam 
in  the  free  state  to  combine  with  a  fresh  portion  of  the  cellulose.  Jentgen  ^ 
also  supports  this  view  of  the  reaction.  Elevated  temperatin-es  also  cause 
the  dilute  acid  to  attach  the  fiber  much  more  quickly  and  severely  than 
otherwise.^  According  to  Biittner  and  Neuman  °  when  cotton  is  treated 
with  dilute  sulfuric  acid  of  sp.  gr.  1.45-1.53  a  mixture  is  obtained  consisting 
probably  of  hydrocellulose  and  oxycellulose  with  more  or  less  unchanged 
cellulose. 

The  action  of  dilute  mineral  acids  on  cotton  seems  to  be  one  of  hydroly- 
sis, whereby  a  molecular  change  occurs  in  the  fiber  substance.  This 
hydrolytic  action  is  supposed  to  result  in  the  formation  of  hydrocellulose, 
having  the  formula  2C6Hio05-H20.  The  action  of  the  acid  no  doubt 
takes  place  in  several  phases,  as  shown  by  the  subsequent  acetylation  of 
the  products.  It  is  quite  certain  that  between  the  body  Ci2H2oOio-H20, 
which  should  correspond  to  the  hydrocellulose  of  Girard,  and  ordinary 
cellulose,  C12H20O10,  there  exists  a  series  of  hydrocelluloses  comprised 
under  the  general  formula,  (C6Hio05)iIl20.  Acetic  acid  has  but  small 
hydrolytic  action,  and  consequently  has  little  effect  on  cotton. 

Knecht  and  Thompson  ^  have  made  a  thorough  study  of  the  action 
of  dilute  sulfuric  acid  on  cotton  and  they  come  to  the  conclusion  that 
the  action  that  takes  place  is  of  a  twofold  nature.     The  cotton  cellulose 

1  Ger.  Pat.  75,572. 

2  Ger.  Pat.  82,857. 

3  Zeit.f.  angew.  Chem.,  1910,  p.  1537. 

*  It  would  seem  that  Kober,  in  1852,  was  the  first  to  recognise  the  action  of  dilute 
mineral  acids  on  cotton  and  to  apply  it  industrially  in  the  treatment  of  half-woolen 
rags  for  the  purpose  of  destroying  the  cotton  and  thus  permittuig  of  tfie  recovery  of 
the  more  valuable  wool  (see  also  sections  relating  to  carbonising). 

5  Zeil.  ang.  Chem.,  1908,  p.  2609. 

6  Jour.  Soc.  Dyers  &  Col.,  1921,  p.  272. 


ACTION  OF  ACIDS  517 

is  partly  hydrolysed,  which  results  in  a  reduction  of  the  strength  of  the 
fiber,  and  there  is  also  a  fixation  of  some  of  the  acid  which  behaves  as  a 
mordant  for  some  of  the  basic  colors.  By  soaking  cotton  in  a  to  percent 
solution  of  sulfuric  acid  and  drying,  both  of  the  actions  take  place,  the 
product  being  tendered  and  exhibiting  a  great  attraction  for  Methylene 
Blue,  Rhodamine  B, .  Crystal  Violet,  and  other  basic  dyes,  even  after 
prolonged  washing  with  water  and  alkali.  It  has,  on  the  other  hand, 
very  little  affinity  for  direct  colors,  notably  Diamine  Sky  Blue.  It  has 
been  indicated  by  other  investigators  that  the  increased  affinity  for 
Methylene  Blue  does  not  depend  on  the  degree  of  tendering.  Thus,  if 
cotton  is  boiled  for  an  hoiu-  with  sulfuric  acid  of  ^  percent  strength,  while 
the  strength  of  the  fiber  is  seriously  impaired,  its  affinity  for  Methylene 
Blue  is  not  increased  but  slightly  diminished.  It  would  seem,  according 
to  Knecht,  that  cotton  cellulose  that  has  been  modified  by  treatment  with 
dilute  sulfuric  acid  is  not  oxidised  cellulose,  but  contains  fixed  sulfur 
which  is  not  removed  by  washing  with  boiling  water  and  alkali.  Also  it  is 
pointed  out  that  oxidised  cellulose  and  the  sulfuric  acid  hydrolysed  cellu- 
lose may  be  distinguished  by  boiling  with  weak  alkali  and  then  dyeing 
with  a  direct  color. 

In  all  dyeing  and  bleaching  operations  where  the  use  of  acid  may  be 
required,  the  above  facts  should  always  be  borne  in  mind ;  the  temperature 
of  the  acid  baths  should  be  not  above  70°  F.,  and  the  acid  strength  should 
not  be  more  than  2  percent.  Where  higher  temperatures  are  necessary, 
organic  acids  should  be  substituted  for  mineral  acids  wherever  possible. 
Acetic  and  formic  acids,  for  instance,  are  often  used. 

Whenever  cotton  is  treated  with  acid  solutions  or  with  salts  of  an 
acid  nature,  or  which  are  liable  to  decompose  with  liberation  of  acid,  all  of 
the  acid  should  be  removed  from  the  fiber  or  properly  neutralised  before 
drying,  else  the  material  will  be  tendered  and  probably  ruined.  The 
action  of  dilute  acid  on  cotton  is  probably  a  hydrolysis  of  the  cellulose 
molecule,  with  the  formation  of  hydrocellulose  causing  a  structural  disor- 
ganisation of  the  fiber. 

The  tendering  of  cotton  dyed  with  sulfur  colors,  which  is  sometimes 
noticed,  is  due  to  the  presence  of  free  sulfuric  acid  arising  from  the  oxida- 
tion of  the  dyestuff.  This  liberation  of  sulfuric  acid  is  accelerated  by 
exposure  to  heat.  Holden  ^  by  exposing  samples  of  cotton  dyed  with  vari- 
ous sulfur  dj^estuffs  to  a  temperature  of  120°  C.  for  twenty  hours,  found 
that  the  material  lost  in  strength  from  39  to  78  percent,  and  the  amount 
of  free  sulfuric  acid  liberated  varied  from  0.027  to  0.078  percent  on  the 
weight  of  the  cotton.  Methods  for  preventing  this  tendering  effect  of 
the  sulfur  dyes  rely  for  their  efficiency  either  on  assisting  the  oxidation 
of  the  dyestuff  (as  in  the  treatment  with  bichromates) ,  or  on  after-treating 
1  Jour.  Soc.  Dyers  &  Col,  1910,  p.  76. 


518 


CHEMICAL  PROPERTIES  OF  COTTON 


the  dyed  material  with  salts  capable  of  neutralising  free  mineral  acids. 
These  latter  compounds  usually  have  the  disadvantage  of  being  soluble  in 
water.  Holden  recommends  the  precipitation  of  calcium  tannate  on  the 
dyed  material. 

Hydrochloric  acid  has  an  effect  similar  to  sulfuric  acid,  and  the  same 
remarks  concerning  the  use  of  this  latter  acid  in  connection  with  cotton 
also  hold  true  for  the  former.  Dry  hydrochloric  acid  gas  does  not  seem 
to  act  on  cotton  at  all,  but  if  moisture  is  present  the  decomposition  is  very 
rapid.  On  this  account  it  is  now  used  quite  extensively  in  the  carbonising 
of  wool-cotton  rags,  the  latter  being  heated  at  212°  F.  with  moist  hydro- 
chloric acid  gas  in  a  special  form  of  apparatus. 

According  to  Knecht  ^  if  cotton  is  steeped  in  hydrochloric  acid  of 
37°  Tw.  the  fiber  will  shrink  and  also  show  a  greatly  increased  affinity 
for  substantive  dyestuffs,  while  at  the  same  time  the  feel  and  the  tensile 
strength  of  the  cotton  are  not  injured.  The  treated  cotton  does  not 
show  any  increased  affinity  towards  tannic  acid  or  the  basic  dyestuffs. 
The  shrinkage  of  cotton  yarn  is  about  4  percent  when  treated  with 
hydrochloric  of  37°  Tw.  and  about  8  percent  with  acid  of  38°  Tw.  With 
hydrochloric  acid  of  40°  Tw.  the  cotton  is  badly  injured,  becoming 
tendered,  harsh  and  brittle. 

According  to  W.  A.  Lawrance,^  when  cotton  yarn  is  treated  with  very 
dilute  acid  and  dried,  charring  does  not  take  place,  but  the  fibers  are  more 
or  less  affected  by  such  a  treatment,  as  is  shown  by  the  loss  of  tensile 
strength.  The  microscope  failed  to  reveal  any  structural  changes  worth 
noting,  and  where  the  loss  in  strength  was  less  than  20  percent  negative 
results  were  obtained  when  tests  for  hydroceUulose  were  made  with  zinc 
chlor-iodide  after  freeing  the  yarn  from  the  last  traces  of  acid. 

The  percentage  decrease  in  tensile  strength  produced  by  dilute  acids 
on  3/8's  cotton  yarn,  under  conditions  described,  is  tabulated  in  the  fol- 
lowing tables : 

Cotton  Yarn  Treated  with  Acid  at  20°  C.  for  Sixteen  Hours 


Concentration  of  the  Acid. 

Temperature  of  Drying. 

1/5N 

1/7N 

1/lON 

1/25N 

1/50N 

1/lOON 

1/150N 

1/200N 

20°  C 

70 
89 
94 
97 
99 

64 
83 
92 
96 
98 

44 
63 
86 
94 
96 

20 
42 
71 
89 
92 

9 
26 
49 

80 
88 

2 

6 

19 

59 

67 

0 

3 

8 

33 

51 

0 

40°  C 

0 

60°  C 

4 

80°  C 

100°  C 

27 
40 

1  Jour.  Soc.  Dyers  <&  Col,  1915,  p.  8. 


^  Canadian  Chemical  Journal,  1922. 


ACTION  OF  ACIDS 


519 


Cotton  Yarn  Treated  with  Acid  at  38°-40°  C.  for  One  Hour 


Concentration  of  the  Acid. 

Temperature  of  Drying. 

1/5N 

1/7N 

1/lON 

1/25N 

1/50N 

1/lOON 

1/150N 

1/200N 

20°  C 

75 

70 

47 

29 

11 

6 

4 

0 

40°  C 

92 

87 

72 

56 

32 

9 

6 

4 

60°  C 

95 

94 

88 

75 

55 

22 

12 

8 

80°  C 

98 

97 

95 

90 

83 

62 

38 

33 

100°  C 

99 

99 

97 

93 

90 

72 

56 

45 

Cotton  Yarn  Treated  with  Acid  at  58°-60°  C.  for  One  Hour 


Concentration  of  the  Acid. 

Temperature  of  Drying. 

1/5N 

1,/7N 

1/lON 

1/25N 

1/50N 

I/IOON 

1/150N 

1/200N 

20°  C. 

79 

73 

52 

30 

13 

8 

6 

5 

40°  C 

93 

89 

75 

59 

40 

14 

10 

7 

60°  C 

96 

95 

89 

76 

58 

25 

15 

10 

80°  C 

99 

98 

96 

91 

85 

70 

44 

37 

100°  C 

100 

100 

97 

94 

92 

78 

60 

49 

Cotton  Yarn  Treated  with  Acid  at  100°  C.  for  One  Hour 


Concentration  of  the  Acid. 

Temperature  of  Drying. 

1/5N 

1/7N 

1/lON 

1/25N 

1/50N 

1/lOON 

1/150N 

1/200N 

20°  C 

40°  C  

88 

96 

98 

100 

100 

84 
94 
97 
99 
100 

70 
88 
91 

97 

98 

37 
65 
81 
93 
96 

20 
50 
68 
88 
95 

11 
17 

28 
77 
84 

9 
13 
19 

60 
66 

7 
10 

60°  C , 

15 

80°  C 

45 

100°  C , 

56 

These  results  clearly  demonstrate  the  sensitivity  of  cotton  to  very 
dilute  acids.     It  is  presumed  that  sulfuric  acid  was  used. 

It  will  be  observed  from  the  data  obtained  that  the  temperature  of 
drjdng  cotton  after  contact  with  very  dilute  inorganic  acid  is  of  more 
importance  than  the  concentration  of  the  acid  within  certain  limits.  For 
instance,  cotton  yarn   treated  with    1   lOON   acid  at  20°  C.  and  dried  at 


520 


CHEMICAL  PROPERTIES   OF   COTTON 


that  temperature  lost  but  2  percent  of  its  strength,  but  when  dried  at 
100^  C  ,  lost  67  percent,  which  is  approximately  the  loss  produced  by 
1  5X  acid  and  d^^^ng  at  20°  C.  Weak  acid  solutions,  with  a  concen- 
tration less  than  1  50N  have  little  immediate  effect  upon  cotton,  pro- 
vided the  chying  takes  place  at  room  temperature,  but  will  tender  more 
or  less  with  age. 

Cohen  ^  has  studied  the  effect  of  dilute  solutions  of  acids  on  cotton 
under  vanning  conditions,  and  the  results  are  shown  in  the  following  table : 


Strength 

Copper  Equivalent. 

of 

Acid 
Used, 

Cotton  Boiled 

inHCl 
for  One  Hour. 

Cotton  Boiled 

in  H2SO4 
for  One  Hour. 

Cotton  Soaked  in  Cold 
HCl,  Dried  and 

Cotton  Soaked  in  Cold 
H2SO4,  Dried  and 

Percent. 

Heated  at  120°  C. 
for  10  Minutes. 

Heated  at  120°  C. 
for  10  Minutes. 

1 

3.256 

2.537 

1 

2.224 

1.822 

i 

1.628 

1 .  325 

1 
s 

1 .  192 

0.994 

1.325 

1 

T6 

0.867 

0.773 

0.994 

A 

0.760 

0.608 

0.805 

A 

0.651 

Same  as  for  dis- 
tilled water 

0.663 

1/100 

0.899 

1  128 

0.597 

0.568 

1,  150 

Same  as  for  dis- 
tilled water 

0.757 

1'200 

0.663 

1  400 

0.568 

Distilled 

water 

0  541 

0  541 

0.531 

0.531 

These  results  indicate  that  if  cotton  is  boiled  in  hydrochloric  acid 
for  one  hour  the  cotton  will  be  affected  when  the  strength  of  the  acid  is 
1  128  percent  and  upward.  Sulfuric  acid  under  the  same  conditions, 
affects  the  cotton  when  the  strength  is  1  32  percent  and  upward.  If 
any  solution  of  acid  weaker  than  these  strengths  is  employed  the  cotton 
is  not  affected.  In  each  case  hydrochloric  acid  has  a  greater  affect  on 
the  cotton  than  has  sulfuric  acid.  It  will  also  be  seen  that  by  heating 
the  cotton  soaked  with  the  dilute  solution  of  acid  the  effect  is  obtained 
with  a  much  weaker  solution.     Cohen  also  gives  the  following  table  showing 


*  Jour.  Soc.  Dyers  <fr  Col.,  1915,  p.  162. 


TESTING  COTTON  FABRICS  FOR  ACID 


521 


the  relation  between  the  copper  equivalents  and  the  tensile  strengths  of 
cotton  vams  after  acid  treatment : 


Cotton  Bofled 
One  Hour  with 
HjSO*.  Percent. 

Tensile  Stroigth 
of  the  Yam, 

Grams. 

Coppo- 
EquivalQit. 

1 

§ 

« 
I 

16 

-1- 
32 

Distilled  water 

220 
340 
390 
440 
495 
535 
575 

2..>i7 
1  S22 
1  325 
0.9^ 
0  773 
0.608 
0.541 

6.  Testing  Cotton  Fabrics  for  Acid. — The  usual  method  of  testing 
for  the  presence  of  acid  in  a  cotton  fabric  is  by  simply  pressing  a  piece  of 
litmus  (blue)  paper  against  the  moistened  cotton,  or  the  cloth  is  boiled 
with  water  and  the  extract  is  tested  with  htmus  or  Methyl  C>range.  To 
estimate  the  quantity  of  acid  the  extract  may  be  titrated  with  a  deci- 
normal  caustic  soda  solution.  It  is  pointed  out,  however,  by  Coward 
and  Wigley  ^  that  these  tests  are  not  satisfactory  as  cotton  exhibits  a 
preferential  attraction  for  the  basic  constituent  of  a  neutral  salt  in 
aqueous  solution.  In  consequence  the  British  Engineering  Standards 
Association  specify  that  in  determining  the  acidity  or  alkalinity  of  aero- 
plane fabric  the  aqueous  extract  should  be  titrated  in  the  absence  of  the 
fabric.  This,  however,  does  not  give  the  true  amoimt  of  acid  or  fllVali 
originally  present  in  the  fabric.  It  ha^  been  shown  by  Z anker  and 
Schnabel-  that  cotton  retains  absorbed  sulfuric  acid  with  such  tenacity 
as  to  introduce  considerable  errors  into  the  estimation  of  small  amounts 
of  that  acid  bj'  titration  of  the  aqueous  extract  of  the  cloth.  Higgrns^ 
has  also  met  with  the  same  difficult^-.  The  best  indicator  for  testing 
the  acidity  of  cloth  is  perhaps  Methyl  Red.  which  gives  a  pink  or  red 
color  with  acid  and  yeUow  with  alkali  and  is  very  sensitive.  A  saturated 
solution  of  Methyl  Red  in  water  gives  a  bright  red  color  when  spotted 
en  cloth  containing  0.005  percent  of  acid  and  a  bright  yellow  color  with 
0.005  percent  of  alkaU  in  cloth.  This  indicator,  therefore,  is  excellent 
for  ascertaining  if  a  cloth  is  well-washed  commercially.  Litmus  paper 
only  gives  a  shght  color  change  with  0.01  p)ercent  of  acid  or  alkali. 

The  following  table  by  Coward  and  Wigley  shows  the  proportion  of 

^Jour.  Teri.  In^.,  1922.  p.  121. 

*  Fdrb.  Zeii..  1913.  p.  282. 

» Jour.  Soc.  Dyers  dt  Col.,  1918.  p.  35. 


522 


CHEMICAL   PROPERTIES   OF  COTTON 


acid  retained  by  bleached  cotton  cloth  after  twice  extracting  with  boiling 
water : 


Acid  Added  to  Cloth 
(Grams  H2SO4  per 
100  Grams  Cloth). 

Acid  Extracted 
from  Cloth. 

Acid  Remaining 
in  Cloth. 

0.008 
0.020 
0.029 
0.061 
0.100 
0.210 

0.000 
0.006 
0.007 
0.018 
0.050 
0.165 

0.008 
0.014 
0.022 
0.043 
0.050 
0.045 

It  was  further  shown  that  acidimetry  (correct  to  0.01  percent  hydro- 
chloric or  sulfuric  acid)  and  alkalimetry  (correct  to  0.02  percent  NaOH 
present  as  Na2C03)  of  bleached  cotton  cloth  can  be  accurately  carried  out 
by  titrations  with  N,  50  solutions,  at  the  boil  in  the  presence  of  the 
fabric,  with  phenolphthalein  as  indicator,  if  the  following  procedure  is 
employed:^  100  cc.  of  distilled  water  are  introduced  into  an  Erlenmeyer 
Hask  brought  to  boil,  1  cc.  of  0.5  percent  phenolphthalein  solution  (in 
alcohol)  is  added  and  titrated  with  N  50  NaOH  until  a  faint  color  per- 
manent for  ten  minutes  is  obtained.  Then  add  3  grams  of  the  cloth 
to  be  tested  and  boil  for  a  few  minutes.  The  liquid  is  then  titrated  with 
N  50  NaOH  until  the  color  remains  permanent  for  ten  minutes. 

Colored  indicators  of  suitable  strength  may  be  used  for  the  approxi- 
mate estimation  of  acidity  or  alkalinity  in  cotton  cloth  by  spotting  on  the 
fabric,  as  follows: 


Indicator. 


Thymol  Blue 

Methyl  Orange 

Lacmoid , 

KI-KIO3  starch. .  . , 

Methyl  Red 

Methyl  Red 

Brom  Thymol  Blue 
Phenolphthalein. . .  , 


AcicUty  or  Alkalinity. 

Color. 

0.16  percent  H2SO4 

Purple 

0.10-0.16  percent  H2SO4 

Yellow-red 

0.06  percent  H2SO4 

Red 

0.01  percent  H2SO4 

Blue 

0.005  percent  H2SO4 

Red 

0.005  percent  NaOH 

Yellow 

0.02  percent  NaOH 

Green 

0 .  12  percent  NaOH 

Pink 

7.  Action  of  Nitric  Acid. — While  dilute  solutions  of  nitric  acid  have 
an  effect  on  cotton  similar  to  other  mineral  acids,  strong  nitric  acid  has  a 
somewhat  different  action.     It  completely  decomposes  cotton,  in  common 
1  McBain,  Jour.  Chem.  Soc.  {Brit.),  1912,  p.  814. 


ACTION  OF  NITRIC  ACID  523 

with  other  forms  of  cellulose,  oxidising  it  to  various  products  among  which 
is  oxalic  acid.  AVlien  boiled  with  moderate^  concentrated  nitric  acid 
cotton  is  converted  into  oxycellulose,  a  structureless,  friable  substance 
possessing  a  great  affinity  for  basic  dyestuffs.  \ATien  mixed  with  con- 
centrated sulfuric  acid,  however,  the  action  of  nitric  acid  on  cotton  is 
totally  different,  the  cellulose  being  converted  into  a  nitrated  body, 
though  the  physical  appearance  of  the  fiber  is  not  appreciably  altered. 
Bronnert  ^  states  that  nitration  of  the  cotton  fiber,  even  to  the  extent  of 
introducing  80  percent  of  nitro  groups,  does  not  appreciably  alter  the 
visible  structure  or  breaking  strain  of  the  thread.  The  exact  nature  of  the 
nitrated  compound  will  depend  on  the  conditions  of  treatment. 

Several  nitrated  celluloses  are  known  and  possess  commercial  impor- 
tance; they  are  classified  under  the  general  name  of  pyroxylins.  Guncotton, 
a  hexanitrated  cellulose,  is  the  most  highly  nitrated  product,  and  is  used 
as  a  basis  of  many  explosives.  Soluble  pyroxlin  is  a  trinitrated  cellulose; 
its  solution  in  a  mixture  of  alcohol  and  ether  is  called  collodion  and  is 
employed  in  sm-gery  and  photograph j\  Another  derivative,  supposed  to 
be  a  tetranitrated  cellulose,  is  also  soluble  in  ether-alcohol  and  its  solu- 
tion has  been  utilised  for  the  production  of  artificial  silk  filaments.  By 
dissolving  nitrated  cellulose  in  molten  camphor  a  substance  known  as 
celluloid  is  formed. 

The  action  of  nitric  acid  on  cotton  fabrics  appears  to  be  a  peculiar  one. 
The  following  observations  in  this  respect  have  been  recorded  bj-  Knecht: 
Bleached  calico  steeped  for  fifteen  minutes  in  pure  nitric  acid  at  80°  Tw., 
washed  and  dried,  showed  a  considerable  contraction,  amounting  to  about 
24  percent;  the  tensile  strength  also  increased  78  percent.  Unbleached 
yarn,  treated  in  the  same  manner,  also  showed  a  considerable  increase 
of  tensile  strength,  and  a  proportional  contraction  in  length.  Weaker 
acids  did  not  show  these  results,  the  fiber  being  tendered  instead  of  being 
strengthened.  Analysis  proved  that  7.7  percent  of  nitrogen  was  present, 
showing  that  about  two  molecules  of  the  acid  had  combined  with  the 
cotton.  The  shrinkage,  gain  in  strength,  microscopical  appearance,  etc., 
of  the  treated  material,  all  go  to  show  that  in  addition  to  the  nitration  a 
mercerising  effect  has  been  produced.  This  appears  in  the  fact  that 
the  material  exliibits  a  strongly  increased  affinity  for  many  dyestuffs, 
especially  the  direct  cotton  colors  and  some  of  the  acid  dyes;  while  by 
reason  of  its  not  showing  any  increased  affinity  for  the  basic  colors  there 
is  proof  that  oxycellulose  has  not  been  produced.  This  action  of  strong 
nitric  acid  on  cellulose  has  been  utilised  for  the  preparation  of  toughened 
filter-papers  which  are  required  to  stand  high  fluid  pressures.  The  filter- 
paper  is  immersed  in  concentrated  nitric  acid  for  a  brief  period  and  then 
well  washed. 

1  Rev.  Gen.  Mat.  Col.  1900. 


524  CHEMICAL  PROPERTIES  OF  COTTON 

The  nitration  of  cotton  yarn  has  been  employed  for  the  purpose  of 
obtaining  a  product  that  will  not  dye  with  direct  cotton  colors  though 
dyeing  rather  well  with  basic  colors.^  The  yarn  to  be  treated  should  be 
free  from  chlorine  and  as  dry  as  possible,  and  also  cold.  An  acid  mixture 
is  prepared  in  a  cast-iron  tank  with  3  parts  of  sulfuric  acid  (168°  Tw.) 
and  1  part  of  nitric  acid  (103°  Tw.).  The  mixed  acid  will  contain  21.5 
to  22.5  percent  of  nitric  acid,  72  to  73  percent  of  sulfuric  acid  and  5  to 
6  percent  of  water.  The  acid  mixture  is  cooled  to  10°  C.  and  then  2 
lbs.  of  the  yarn  are  steeped  for  one  hour  in  80  lbs.  of  the  acid.  The  yarn 
is  then  lifted,  the  excess  of  acid  is  squeezed  out,  and  then  hydroextracted. 
The  yarn  is  then  brought  in  small  quantities,  and  as  quickly  as  possible, 
into  a  relatively  large  amount  of  water  to  prevent  heating.  If  the  yarn 
is  properly  submerged  the  strength  of  the  cotton  will  not  be  impaired, 
while  the  length  of  the  skein  and  the  texture  of  the  fiber  will  not  be 
altered.  The  yarn  is  then  washed  in  warm  water  and  finally  boiled  in  a 
dilute  solution  of  soda  ash  until  all  trace  of  acid  is  removed.  The  nitrated 
product  obtained  in  this  manner  is  a  hexanitrate  and  is  described  as 
perfectly  safe,  igniting  only  when  a  temperature  of  180°  C.  is  reached. 
By  weaving  cotton  yarn  prepared  in  this  manner  with  ordinary  cotton 
yarn  or  mercerised  yarn,  and  then  dyeing  with  suitable  direct  cotton 
dyes,  remarkable  two-color  effects  may  be  obtained,  or  the  treated  cotton 
may  be  left  practically  undyed. 

If  nitrated  cotton  be  examined  under  the  microscope,  a  considerable 
alteration  in  its  appearance  will  be  observed.  The  fibers  have  a  much 
thicker  cell- wall,  and  are  consequently  stiff er  than  those  of  ordinary  cotton. 
The  lumen  has  either  vanished  entirely  or  become  very  much  contracted, 
and  this  appears  to  be  due  to  the  swelling  of  the  cell-walls.  In  the  walls 
of  the  fiber  there  will  also  be  noticed  numerous  fractures  or  cracks  which 
often  assume  a  spiral  shape.  The  nitration  has  evidently  rendered  the 
fiber  much  more  brittle  and  has  decreased  its  elasticity. 

Hoepfner  has  prepared  porous  acid-proof  fabrics  to  be  employed  for 
filtering  purposes  in  electrolytic  work  by  using  cotton  yarn  which  has  been 
nitrated.  The  latter  can  be  woven  along  with  asbestos,  glass,  or  other 
mineral  fibers  in  the  making  of  the  fabric.  According  to  Claessen  acid- 
proof  filter  cloths  may  be  prepared  by  first  immersing  the  cloth  in  cold 
nitric  acid  of  40°-50°  Be.,  then  in  concentrated  sulfuric  acid  of  60°  Be., 
finally  washing  with  water  until  neutral.  By  this  means  a  superficial 
nitration  only  is  effected.^  F.  Bayer  &  Co.^  state  that  completely  nitrated 
cloth  may  be  produced  by  immersion  first  in  nitric  and  then  in  sulfuric 
acid  and  that  the  cloth  so  prepared  is  superior  in  quality  and  strength 

1  Schneider,  Jour.  Soc.  Dyers  *  Col,  1907,  p.  78. 

2  See  Zeii.  ang.  Chem.,  1906,  p  317. 
'  See  U.  S  Pal.  850,206  of  1908. 


ACTION  OF  NITRIC  ACID  625 

to  that  formed  from  weaving  threads  made  from  nitrocellulose  solutions, 
being  nearly  twice  as  strong  and  more  resistant  to  acids  and  chlorine  while 
at  the  same  time  being  open  and  porous.  To  produce  solid  cloths  which 
are  acid-proof,  Bachrach  ^  recommends  the  addition  of  graphite  or  bitu- 
men. It  is  said  that  10  percent  of  either  of  these  will  produce  a  cloth 
which  will  successfully  resist  long  contact  with  corrosive  chemicals. 
Nitrocellulose  may  be  blended  with  the  graphite  or  bitumen  by  use  of  an 
acid-resisting  solvent  known  as  "  picamer  "  ^  which  will  dissolve  nitrate 
of  cellulose.  Picamer  is  obtained  by  fractionating  wood  tar  distillate 
with  chromic  acid  or  alkaline  potassium  bichromate. 

A  process  for  giving  cotton  a  wool-like  character  by  treatment  with 
nitric  acid  is  described  by  C.  Schwartz.^  It  has  been  found  that  a  wool- 
like character  may  be  imparted  to  cotton  or  other  vegetable  fabrics  by 
treating  them  at  the  ordinary  temperature  with  a  solution  of  nitric  acid 
of  over  65  percent  strength,  and  then  washing  out  the  acid.  The  textile 
material,  in  the  form  of  fabric,  or  yarn,  for  example,  is  steeped  in  a  large 
excess  of  concentrated  nitric  acid,  in  which  it  floats  freely  without  tension, 
until  the  reaction  is  terminated;  then  it  is  squeezed  or  dried  out  and 
washed.  The  time  of  contact  depends  upon  the  concentration  of  the  acid 
and  the  quality  of  the  textile  material,  especially  its  porosity  and  absorbent 
capacity.  For  example,  one  minute  will  be  sufficient  soaking  for  ordinary 
plain  fabrics,  in  75  percent  nitric  acid;  two  minutes  for  ordinary  calicos 
in  72  percent  acid;  five  minutes  for  fine  Egyptian  cotton  batistes  in  65 
percent  acid.  This  treatment  in  nitric  acid  may  be  prolonged  up  to  five, 
ten  or  thirty  minutes  respectively,  without  harm  as  to  the  final  result,  on 
condition  that  the  temperature  does  not  exceed  68°  F. ;  this  fact  is  of 
great  importance  in  manufacture  on  a  large  scale,  where  it  is  always 
necessary  to  take  account  of  the  possibility  of  stoppages  or  other  causes 
bringing  the  apparatus  to  a  standstill  for  a  time.  For  practical  reasons, 
the  temperature  of  the  acid  is  maintained  at  a  comparatively  low  tem- 
perature to  avoid  the  evolution  of  acid  vapors,  but  it  is  possible  to  reach 
77°  F.  without  risk  to  the  material  under  treatment.  With  nitric  acid  of 
a  concentration  between  65  percent  and  75  percent,  it  is  possible  with- 
out inconvenience  and  at  the  ordinary  temperature,  to  allow  the  action 
of  the  nitric  acid  upon  the  fiber  to  be  prolonged.  When,  on  the  other 
hand,  this  concentration  limit  of  75  percent  is  exceeded,  it  is  necessary 
to  insure  that  the  nitric  acid  acts  upon  the  fiber  only  for  a  very  short 
time,  some  few  minutes.* 

1  U.  S.  Pat.  692,102  of  1902. 

2  Greening,  Bnt.  Pat.  22,019  of  1894 

3  U.  S.  Pat.  1,384,677. 

*  A  new  method  which  is  said  to  be  the  basis  of  an  important  commercial  process 
is  described  by  J.  E.  PoUak  in  British  Patent  167,864.     It  has  for  its  purpose  the  con- 


526  CHEMICAL  PROPERTIES   OF   COTTON 

The  following  are  descriptions  of  the  principal  nitrated  products  of 
cotton  cellulose.  In  the  formulas  given  the  cellulose  unit  group  is  taken 
as  C12H20O10. 

Cellulose  hexanitrate,  or  guncotton,  Ci2Hi404(N03)6,  is  made  by  the  use  of  3  parts 
nitric  acid  of  sp.  gr.  1.5  and  1  part  sulfuric  acid  of  sp.  gr.  1.84.  The  cotton  is 
immersed  in  this  mixture  for  twenty-four  hours  at  a  temperature  not  above  10°  C; 
100  parts  of  cellulose  yield  about  175  parts  of  the  nitrate.  This  nitrate  is  insoluble 
in  alcohol,  ether,  or  in  mixtures  of  both,  in  glacial  acetic  acid,  or  methyl  alcohol; 
slowly  soluble  in  acetone.  Ordinary  gimcotton  may  contain  as  much  as  12  percent 
of  nitrates  soluble  in  ether-alcohol  mixture. 

Cellulose  pentanitrate,  Ci2Hi605(N03)6,  is  prepared  by  dissolving  guncotton  (the 
hexanitrate)  in  nitric  acid  at  80°  to  90°  C,  and  precipitating  by  the  addition  of  sulfuric 
acid  after  cooling  to  0°  C.  The  precipitate  consists  of  the  pentanitrate,  and  is  purified 
by  washing  with  water,  then  with  alcohol,  dissolving  in  ether-alcohol,  and  reprecipitating 
with  water.  The  pentanitrate  is  insoluble  in  alcohol,  is  slightly  soluble  in  acetic  acid, 
and  readily  so  in  ether-alcohol;  by  treatment  with  strong  caustic  potash  it  is  con- 
verted into  the  dinitrate. 

Cellulose  tetra-  and  trinitrates  (collocUon  pyroxylin)  are  formed  simultaneously 
when  cotton  is  treated  with  a  more  dilute  acid  and  at  higher  temperatures,  and  for  a 
shorter  time  than  in  the  preparation  of  the  hexanitrate.  As  these  two  nitrates  are 
soluble  to  the  same  extent  in  ether-alcohol,  acetic  ether,  and  methyl  alcohol,  it  is  not 
possible  to  separate  them.  WTien  treated  with  a  mixture  of  concentrated  nitric  and 
sulfuric  acids,  they  are  both  converted  into  penta-  and  hexanitrates;  caustic  potash 
and  ammonia  convert  them  into  the  dinitrate. 

Cellulose  dinitrate,  Ci8Hi308(N03)2,  is  formed  through  a  partial  saponification  of 
the  higher  nitrates  by  the  action  of  caustic  potash,  and  also  by  the  action  of  hot  dilute 
nitric  acid  on  cellulose.  The  dinitrate  is  very  soluble  in  ether-alcohol,  acetic  ether, 
and  in  absolute  alcohol. 

version  of  the  cotton  fiber  into  material  which  is  of  a  transparent  nature  while  at  the 
same  time  it  acquires  a  wool-like  character.  The  operation  is  really  based  on  the 
production  of  nitrated  cellulose  or  collodion  right  on  the  fabric,  and  is  carried  out 
by  treating  the  cloth  for  a  few  seconds  with  a  mixture  of  an  equal  volume  each  of 
sulfuric  acid  (134°  Tw.)  and  nitric  acid  (78°  Tw.)  cooled  to  a  temperature  of  32°  F. 
or  lower.  The  fabrics  are  then  washed  thoroughly  and  dried  on  a  stenter  frame.  The 
strength  of  the  nitrifying  acid  mixture  may  be  varied  according  to  whether  a  wool-like 
or  a  transparent  effect  is  desired. 

The  application  of  such  a  corrosive  acid  mixture  to  a  cotton  fabric  would  be  regarded 
with  dismay  by  most  textile  chemists,  and  if  carried  out  in  the  simple  manner  outlined 
would  no  doubt  be  attended  with  a  complete  destruction  of  the  fiber.  But  that  it  is 
quite  possible  to  regulate  and  control  the  chemical  action  of  this  acid  mixture  on 
cotton  is  evidenced  by  the  successful  commercial  application  of  concentrated  sulfuric 
acid  solutions  to  cotton  in  the  production  of  the  so-called  Swiss  Finish.  The  applica- 
tion of  the  nitrifying  acid  mixture  must  be  carried  out  in  suitable  machines  so  adjusted 
as  to  leave  the  fiber  in  contact  with  the  acid  for  only  a  prescribed  short  space  of  time, 
and  then  the  removal  of  the  acid  mixture  must  be  so  conducted  as  to  prevent  injury 
to  the  goods.  The  patent  simply  describes  the  mere  outline  of  the  process  and  there 
are  many  points  largely  of  a  mechanical  nature  which  would  have  to  be  thoroughly 
perfected  in  order  that  such  a  treatment  might  be  conducted  in  a  successful  commercial 
manner. 


ACTION  OF  ORGANIC  ACIDS 


527 


Vielle  has  studied  the  nitration  of  cotton  with  different  concentrations 
of  acid  with  the  following  results: 


Density  of 
Nitric  Acid. 

1.502  I 
1.497 


1.488 
1.483 


Product  Obtained. 

Structural  features  of  cotton  preserved;  soluble  in 
acetic  ether;  not  in  ether  alcohol: 

C24H2o(N03H)ioOio. 

Appearances  unchanged;  soluble  in  ether-alcohol; 
collodion  cotton: 

C24H22(N03H)90u,       C24H24(N03H)80i2. 

Fiber  still  unresolved;  soluble  as  above,  but  solutions 
more  gelatinous  and  thready: 

C24H26(N03H)70l3. 

Dissolve  cotton  to  viscous  solution;  products  pre- 
cipitated by  water;  gelatinised  by  acetic  ether;  not 
by  ether  alcohol: 

C24H28(N03H)60„. 

Friable  pulp;  blued  strongly  by  iodine  in  potassium 
iodide  solution;  insoluble  in  alcohol  solvents: 

C24H30(NO3H)5Ol5,        C24H32(N03H)40l6. 


8.  Action  of  Hydrofluoric  Acid. — The  action  of  strong  hydrofluoric 
acid  on  cotton  and  other  vegetable  fibers  appears  to  be  a  peculiar  one; 
a  transparent,  tough,  flexible  waterproof  material  being  obtained.  The 
product  does  not  appear  to  resemble  parchment  obtained  by  the  action 
of  sulfuric  acid.  It  is  used  as  an  insulating  material  and  for  making 
the  carbon  filaments  of  incandescent  electric  lamps. 

Hydrofluoric  acid  and  its  compounds,  sodium  acid  fluoride  and  the 
silico-fluoride,  are  used  quite  extensively  in  dilute  solutions  as  cleansing 
agents  for  removing  stains  (especially  of  iron  rust)  from  cotton  fabrics  in 
laundries  and  dry  cleaning  establishments. 

9,  Action  of  Organic  Acids. — Organic  acids  in  solution,  even  when 
moderately  concentrated,  do  not  appear  to  have  any  injurious  action  on 
cotton.  The  non-volatile  acids,  however,  such  as  oxalic,  tartaric,  and 
citric  acids,  when  allowed  to  dry  into  the  fiber,  act  much  in  the  same 
manner  as  mineral  acids,  especially  at  elevated  temperatures. 

Acetic  acid,  being  volatile,  exerts  no  destructive  action;  hence  this 
latter  acid  is  particularly  suitable  for  use  in  the  dyeing  and  printing  of 
cotton  goods,  where  the  use  of  an  acid  is  requisite. 

The  effect  of  certain  acids  on  the  strength  of  cotton  is  an  important 
factor  in  printing.  The  following  table  shows  the  degree  of  weakening 
caused  by  various  acids,  strips  of  calico  being  printed  with  tragacanth 
pastes  containing  20  grams  of  oxalic  acid  per  liter,  or  an  equivalent  amount 


528 


CHEMICAL    PROPERTIES  OF   COTTON 


of   the  other  acids,  and  in  the  first  case  exposed  for  four  hours  to  the 
ordinary  temperature,  and  in  the  second  case  steamed  for  one  hour; 


Acid. 

I. 

Percent. 

II. 
Percent. 

Oxalic 

Tartaric 

Ortho-phosphoric 

Meta-phosphoric          

25 

5 

1.5 
31.5 
35.0 
27 

25 

10 

15 

35 

35.5 

28 

Pyro-phosphoric 

Phosphorous 

Under  similar  conditions  sulfocyanic  acid  has  but  a  very  shght  tendering 
effect  on  printed  cotton,  even  under  the  influence  of  steaming,  but  under 
the  influence  of  hot  dry  air  its  tendering  action  is  greater  than  that  of 
oxahc  acid.  The  addition  of  such  substances  as  glucose  appears  to  exert 
a  protecting  influence  in  connection  with  the  above  acids. 

Rothwell  ^  has  investigated  the  relative  effects  of  various  organic  acids 
on  bleached  cotton  cloth.  Pieces  of  thoroughly  bleached  cloth  were 
padded  in  solutions  of  citric,  tartaric  and  oxalic  acids  of  various  strengths, 
dried  at  a  low  temperature  and  then  steamed  for  one  hour  at  5  lbs.  pressure. 
The  results  are  shown  in  the  following  tables:  (the  breaking  strength  of  the 
original  cloth  was  139  lbs.  and  when  steamed  only,  136.5  lbs.) 


Acid  Used. 

Solution, 
Percent. 

Breaking 
Strength, 
Pounds. 

Citric 

Tartaric 

Oxalic 

Citric 

1.25 

1.25 

1.25 

0.625 

0.625 

0.625 

79 

52 

Disintegrated 

102 

75 
Disintegrated 

Tartaric 

Oxalic 

It  is  evident,  therefore,  that  tartaric  acid  has  a  much  greater  action  on 
cotton  than  citric  acid. 

The  destructive  action  of  these  acids  on  the  cotton  fiber  is,  perhaps,  not 
so  much  of  a  chemical  nature  as  mechanical,  it  being  caused  by  the  acids 
crystallising  within  the  fiber  and  thus  breaking  the  cell-wall.  A  dry  heat, 
for  instance,  in  connection  with  these  acids  is  much  more  injurious  than  a 
moist  heat,  a  fact  which  is  of  much  importance  in  the  drying  of  cotton 
prints,  where  the  above-mentioned  acids  may  have  been  used.  Scheurer  ^ 
1  Dyer  &  Cal.  Printer,  1893.  ^  j^^^n  .^q^  j^d.  Mulh.,  August,  1900. 


ACTION  OF  ORGANIC  ACIDS  529 

has  studied  the  action  of  lactic,  oxalic,  tartaric,  and  citric  acids  on  cotton, 
both  in  hot  air  and  in  steam.  The  result  of  his  investigations  showed: 
(1)  Lactic  acid  tenders  the  fabric  at  least  as  much  as  tartaric  and  citric 
acids;  oxalic  acid  being  the  most  energetic  in  this  respect;  (2)  the  tender- 
ing takes  place  just  as  much  before  steaming  as  after. 

Oxalic  acid  appears  to  have  a  peculiar  effect  on  cotton;  it  has  been 
noticed  that  if  a  piece  of  cotton  cloth  be  printed  with  a  thickened  solution 
of  oxalic  acid,  dried,  and  hung  in  a  cool  place  for  about  twelve  hours,  and 
then  well  washed,  the  printed  parts  exhibit  a  direct  affinity  toward  the 
basic  dyes.  The  cotton  so  treated  does  not  become  greatly  tendered  or 
otherwise  changed.  Toward  substantive  dyes  it  exhibits  considerably  less 
attraction  than  ordinary  cotton,  while  with  ahzarine  dyes  it  is  partially 
reactive.  Tartaric  and  citric  acids  do  not  produce  the  same  effect,  nor 
does  the  neutral  or  acid  oxalate  of  potassium.^ 

Scheurer  ^  has  also  made  some  studies  on  the  action  of  tartaric  acid 
on  cotton  in  connection  with  steaming  as  an  operation  in  printing.  He 
found  that  a  sample  treated  with  tartaric  acid  and  exposed  to  a  temperature 
of  1 10°  C.  for  fifteen  minutes  showed  as  much  tendering  as  a  similar  sample 
steamed  at  98°  to  99°  C.  for  If  hours.  He  concludes  that  when  cotton 
is  impregnated  with  tartaric  acid  it  is  very  sensitive  to  the  hygrometric 
condition  of  the  steam. 

Pilkington  ^  has  studied  the  tendering  action  on  cotton  of  various  or- 
ganic acids,  using  the  copper  value  of  the  treated  cotton  as  a  measure  of 
the  effect.     His  results  are  given  in  the  following  table: 


Method  of  Treatment. 


Copper  Value. 


Blank,  with  3  grams  of  untreated  cotton 

Cloth  treated  with  5  grams  per  100  cc.  of  tartaric  acid  alone 

Cloth  treated  with  5  grams  of  tartaric  acid  and  1  gram  of  glaubersalt 
per  100  cc 

Cloth  treated  with  5  grams  of  tartaric  acid  and  0.2  gram  of  glauber- 
salt per  100  cc 

Cloth  treated  with  5  grams  of  tartaric  acid  and  0.4  gram  of  glauber- 
salt per  100  cc 

Cloth  treated  with  5  grams  of  tartaric  acid  and  0.8  gram  of  glauber- 
salt per  100  cc 

Cloth  treated  with  5  grams  of  tartaric  acid  and  1 .6  grams  of  glauber- 
salt per  100  cc 


1.35 

4.80 

4.57 
4.27 
3.40 
3.14 

2.82 


'  Fumaric  and  maleic  acids  have  been  suggested  for  use  with  cotton .  In  the 
dyeing  of  cotton,  fumaric  acid  is  unsuitable  because  of  its  insolubility;  but  for  dis- 
charging in  calico  printing  maleic  acid  is  a  good  substitute  for  tartaric  acid  when  used 
for  certain  colors,  and  for  oxalic  acid  when  used  for  discharging  indigo.  There  is  a 
danger,  however,  of  tendering  the  fabric  and  corroding  the  copper  rollers  if  much 
acid  is  used  in  the  printing  pastes. 

2  Bull.  She.  Ind.  Mulh.,  1893. 

'  Jour.  Soc.  Dyers  &  Col,  1915,  p.  149. 


530 


CHEMICAL   PROPERTIES   OF   COTTON 


This  indicates  that  the  presence  of  the  neutral  salt  decreases  the 
effect  of  the  acid  on  the  cotton.  The  following  table  gives  the  effect  of 
various  acids: 


Copper  Values. 

Acids  at  2  Grams 
per  100  cc. 

Alone. 

With  2  Grams 

of 

Glaubersalt 

per  100  cc. 

With  20  Grams  of 
Glaubersalt  per  100  cc. 

Found. 

Corrected. 

Oxalic 

Tartaric 

Citric 

7.47 
3.38 
3.06 

7.47 
3.09 
2.26 

2.26 
1.98 
1.48 

2.47 
2.17 
1.66 

Fort  and  Pickles  ^  give  the  following  table  showing  the  effect  of  various 
organic  acids  on  the  strength  and  elasticity  of  cotton  yarns  under  conditions 
of  padding  and  heating: 


Padded  with  2N  Solution 
of 


Gray  yarn 

Oxalic  acid 

Orthophosphoric  acid 

Chloracetio  acid 

Tartaric  acid 

Formic  acid 

Acetic  acid 


Dried  at  20°-30°  C. 


Tensile 
Strength, 
Ounces. 


11.49 
7.08 
6.18 

10.07 
9.18 

11.09 

11.53 


Elongation, 
Percent. 


5.425 

3.75 

3.40 

5.48 

4.45 

5.35 

6.10 


Heated  to  100°  C. 


Tensile 
Strength, 
Ounces. 


1.87 

4.51 

4.58 
6.87 
7.7 


Elongation, 
Percent. 


1.48 

2.75 
2.92 
3.65 
4.45 


Cross  and  Briggs  ^  have  shown  that  acetylation  of  cotton  has  the  effect 
of  making  it  resist  the  dyeing  of  direct  cotton  colors.  The  method  con- 
sists in  digesting  the  previously  dried  cotton  with  a  mixture  containing 
acetic  anhydride,  glacial  acetic  acid,  and  zinc  chloride.  The  composition 
of  the  mixture  varies  with  the  degree  of  acetylation  required.  Suitable 
mixtures  for  hard  yarn  may  be  made  as  follows: 

1  Jour.  Soc.  Dyers' &  Col,  1915,  p.  256. 
^Jour.  Soc.  Dyers  &  Col,  1908,  p.  189. 


ACTION  OF  TANNINS 


531 


Acetic  anhydride . 
Acetyl  chloride . . . 
Glacial  acetic  acid 
Zinc  oxide 


Mixture  A, 

For  Gain  of  26  Percent 

in  Weight. 


Mixture  B, 

For  Gain  of  34  Percent 

in  Weight. 


42 
11.5 
25 
6.5 


Of  "  A  "  use  twice  the  weight  of  the  dry  cotton  and  of  "  B  "  use  2.3  times 
the  weight  of  the  dry  cotton.  The  cotton  is  impregnated  with  the  mixture 
and  the  reaction  is  complete  at  the  end  of  forty-eight  hours  at  a  tempera- 
ture of  35°  C,  and  the  yarn  is  then  washed  off  and  dried.  The  yarn 
treated  in  this  manner  shows  a  gain  in  weight  and  resists  very  well  dyeing 
with  substantive  colors,  though  showing  an  increased  affinity  for  basic 
dyes.  It  also  resists  the  action  of  cold  caustic  soda  solution  of  mercerising 
strength.  If  a  piece  of  the  acetylated  fabric  be  immersed  for  two  or  three 
minutes  in  caustic  soda  of  40°  Tw.,  the  stripes  of  ordinary  cotton  are 
mercerised  and  shrink,  whilst  the  stripes  of  acetylated  cotton  resist  the 
action.  The  fabric  should  be  washed  and  soured  as  soon  as  the  mercerisa- 
tion  is  effected,  otherwise  a  slow  saponification  of  the  acetate  will  take 
place.  The  mercerisation  throws  up  the  stripes,  and  the  dyeing  phe- 
nomena are  in  the  main  unchanged.  Lastly,  it  may  be  mentioned  that  the 
acetylating  process  can  be  applied  to  cotton  fabrics  in  the  piece,  and 
that  the  treatment  imparts  a  finish  and  firmness  resistant  to  careful 
washing  (cold  soaping).  Other  industrial  advantages  may  possibly  be 
derived  from  the  fact  that  the  normal  hygroscopic  moisture  of  these 
acetylated  cottons  is  only  about  one-half  of  that  of  the  original  cotton. 

10.  Action  of  Tannins. — Tannic  acid,  unlike  other  acids,  exhibits  quite 
an  affinity  for  cotton,  the  latter  being  capable  of  absorbing  as  much  as 
7  to  10  percent  of  its  weight  of  tannic  acid  from  an  aqueous  solution. 
Advantage  is  taken  of  this  fact  in  the  mordanting  of  cotton  with  tannic 
acid  and  tannins  for  the  dyeing  and  printing  of  basic  colors.  Cotton 
exhibits  a  similar  attraction  for  tungstic  acid;  the  expense  of  this  latter 
compound,  however,  precludes  its  adoption  as  a  mordanting  agent. 

According  to  Georgevics  ^  the  absorption  of  tannin  by  cotton  proceeds 
in  accordance  with  the  following  equation: 

Vr" 

-^'  =  X(0.10to0.12). 
^/ 

where  Ct  indicates  the  amount  of  tannin  remaining  in  the  bath  calculated 
to  100  cc.  of  solution,  and  C/  indicates  the  quantity  of  tannin  taken  up  b}' 
the  fiber,  calculated  to  100  grams  of  cotton. 

1  Fdrb.  Zeit.,  1899,  p.  214. 


532 


CHEMICAL  PROPERTIES   OF   COTTON 


According  to  Knecht  ^  tannic  acid  is  absorbed  by  cotton  in  its  various 
forms  as  follows: 


Form. 

Tannic  Acid 
Taken. 

Tannic  Acid 
Absorbed. 

Bleached  cotton 

0 .  25  gram 
0.25     " 
0.25     " 
0.25     " 

0.0513  gram 
0.0563     " 
0.1033     " 
0.1525     " 

Unbleached  cotton 

Mercerised  cotton 

Precipitated  cellulose 

Though  tannic  acid  is  readily  taken  up  by  cotton,  gallic  acid  is  not 
absorbed  under  ordinary  conditions.  Gardner  and  Carter-  give  the 
relative  amounts  of  tannins  (and  similar  bodies)  absorbed  by  cotton; 
10  grams  of  cotton  were  soaked  for  three  hours  in  a  solution  containing 
1  gram  of  reagent  per  liter : 

.^  ^  Percent. 

^^^S"^^-  Absorbed. 

Gallotannic  acid 32 

Catechutannic  acid 32 

Gallic  acid 0 

Pyrogallol 4.5 

Phloroglucinol 24 

Protocatechuic  acid 0 

Resorcinol 45 

Salicylic  acid 0 

Guaiacol 0 

Mendelic  acid 7 

Pyrocatechol 0 

Koechlin  found  that  cotton  saturated  with  tannic  acid  in  a  solution 
containing  50  grams  per  liter  was  still  able  to  absorb  tannic  acid  from  a 
solution  containing  20  grams  per  liter.  It  retained  the  whole  of  its  tannic 
acid  in  a  solution  containing  5  grams  per  liter,  and  only  began  to  lose  it 
when  the  strength  was  reduced  to  2  grams. 

The  effect  of  adding  other  acids  to  the  tannic  acid  solution  is  as  follows 
(the  acids  being  present  in  quantities  equivalent  to  4.5  grams  of  acetic 
acid  per  liter) : 

„  ,  ,.  Percent 

bolution.  .,       ,    J 

Absorbed. 

Tannic  acid  alone  (as  above) 32 

' '          +formic  acid 48 

' '          +acetic  acid 48 

*  *          +propionic  acid 48 

*  *          +citric  acid 19 

* '          +tartaric  acid 20 

'  *          4-sulfurio  acid 18 

' '          +hydrochloric  acid 30 

' '          +sodium  acetate 16 

1  Jour.  Soc.  Dyers  &  Col,  1892,  p.  40.        ^  j^^^.  Sac.  Dyers  &  Col,  1898,  p.  143. 


ACTION   OF   DILUTE  ALKALIES 


533 


11.  Action  of  Dilute  Alkalies. — Though  acids,  in  general,  have  such  an 
injurious  action  on  cotton,  alkalies,  on  the  other  hand,  are  harmless 
under  ordinary  conditions.  Dihite  solutions  of  either  the  carbonated  or 
caustic  alkalies,  even  at  a  boiling  temperature,  if  air  is  excluded,  have  no 
injurious  effect  on  cotton. 

In  the  presence  of  air  alkaline  solutions  cause  a  hydrolysis  of  the 
cellulose  in  a  manner  similar  to  acids,  with  the  result  that  the  fiber  is 
seriously  weakened.  The  prolonged  action  of  alkalies  in  the  presence  of 
air  is  an  important  one  to  bear  in  mind  in  the  operations  of  bleaching, 
dyeing,  or  mercerising. 

Boiling  solutions  of  dilute  alkalies  dissolve  or  emulsify  the  waxy  and 
fatty  impurities  encrusting  the  cotton  fiber,  hence  these  reagents  are 
largely  employed  in  the  scouring  of  cotton  goods. 

The  absence  of  air  in  the  kier  boiling  of  cotton  goods  previous  to 
bleaching  is  a  very  important  factor.  The  presence  of  air  in  the  kier 
with  the  caustic  alkali  not  only  causes  oxidation  and  consequent  tendering 
and  discoloration,  but  it  also  tends  to  produce  air  bubbles  by  expansion 
on  heating,  and  these  protect  the  fiber  from  the  action  of  the  alkali. 

Scheurer  ^  has  shown  that  cotton  fabrics  when  boiled  out  in  1  to  8 
percent  solutions  of  caustic  soda  at  150°  C.  if  no  trace  of  air  is  present 
indicate  no  weakening  of  the  fiber;  but  if  even  minute  quantities  of  air 
are  present  the  fabric  will  be  considerably  weakened. 

Weber-  has  observed  that  in  dyeing  cotton  in  alkaline  baths  the 
fiber  may  be  considerably  affected.  Cotton  was  exposed  during  six 
hours  to  the  action  of  oxygen  and  air,  under  such  conditions  as  would 
actually  obtain  in  dyeing,  the  cotton  being  immersed  at  the  boiling  point 
in  baths  containing  5  percent  of  various  alkalies.  The  loss  in  weight  of 
the  cotton  was  observed  with  the  following  results: 


Alkalies,  5  Percent. 


Caustic  soda 

Caustic  potash 

Sodium  carbonate.  .  . 
Potassium  carbonate 

Borax 

Sodium  phosphate. .  . 


Percent  Loss  in  Weight  with 


Oxygen. 


11.0 

22.8 

8.2 

13.7 

5.9 

3  1 


Steam  and 
Oxygen. 


17.3 
29.8 
10.1 
16,4 
6.8 
3.5 


Air. 


5.2 
8.4 
3.9 
5.3 
2.2 
2.0 


Steam  and 
Air. 


9.2 
11.7 
5.4 
6.9 
2.8 
2.3 


1  Bull.  Ind.  Soc.  Mulh.,  1888,  p.  362. 
"^Jour.  Soc.  Chem.  Ind.,  1893,  p.  US. 


534 


CHEMICAL  PROPERTIES  OF  COTTON 


In  every  case  the  fiber  was  found  to  have  lost  in  tensile  strength,  and  in 
some  instances  to  be  practically  destroyed.  The  difference  in  the  action 
of  sodium  and  potassium  compounds  is  somewhat  remarkable,  and  would 
naturally  lead  us  to  avoid  the  use  of  caustic  potash  or  potassium  carbonate 
in  the  dyeing  of  cotton. 

The  loss  of  weight  by  boiling  cotton  in  caustic  soda  solution  is  given  as 
follows : 


Strength  of 
Solution, 
Percent. 

Loss  on  Boiling  for 

30  Minutes,  Percent. 

1  Hour,  Percent. 

1 
2.5 

4.41 
5.08 

5.71 
7,33 

According  to  Bumcke  and  Wolffenstein,^  when  cotton  is  boiled  eight 
times  consecutively  with  30  percent  caustic  soda  solutions,  the  cellulose  is 
completely  dissolved  to  a  dark  brown  solution.  On  acidifying  this  solution 
a  copious  precipitate  of  add  cellulose  is  obtained  which  seems  to  be  identical 
with  the  hydralcellulose  obtained  by  the  action  of  hydrogen  peroxide  on 
cellulose. 

The  action  of  alkaline  solutions  at  high  temperatures  (above  100°  C.) 
on  cotton  appears,  however,  to  be  a  destructive  one.  Tauss  has  shown 
that  if  cotton  be  digested  with  solutions  of  caustic  soda  under  pressure, 
the  fiber  is  attacked  and  converted  into  soluble  products;  the  degree  of 
decomposition  depending  on  the  pressure  and  the  strength  of  the  alkaline 
liquor,  in  accordance  with  the  following  table : 


Pressure. 

Strength  of  Alkah. 

3  Percent  NajO. 

8  Percent  NaaO. 

Percent  of  Cotton  Dissolved. 

1  atmosphere 

5  atmospheres 

10            "           

12.1 
15.4 
20.3 

22.0 
58.0 
59.0 

Under  these  conditions  it  is  probable  that  a  hydration  of  the  cellulose 
at  first  takes  place,  followed  subsequently  by  a  hydrolysis. 

^  Berichte,  1890,  p.  2501. 


ACTION  OF  DILUTE  ALKALIES 


535 


Solutions  of  ammonia  do  not  act  on  cotton  until  quite  high  temperatures 
are  reached.  According  to  the  experiments  of  L.  Vignon,  at  200°  C. 
ammonia  reacts  with  cotton  cellulose,  the  result  being  the  evident  forma- 
tion of  an  amino-cellulose  compound,  the  product  evincing  a  greatly 
increased  degree  of  absorption  for  dyestuff  solutions,  especially  for  the  acid 
coloring  matters,  somewhat  after  the  manner  of  animal  fibers.  The  same 
effect  is  said  to  be  obtained  when  cotton  is  treated  with  calcium  chloride 
and  ammonia  at  a  temperature  above  60°  C. 

The  action  of  alkaline  solutions  on  cotton  under  high  pressure  has  an 
important  bearing  on  the  bleaching  of  this  fiber,  where  it  is  subjected  to 
such  action  by  boiling  with  alkalies  in  pressure  kiers.  This  phase  of  the 
question  does  not  appear  to  have  received  much  attention  from  either  the 
practical  bleacher  or  the  theoretical  chemist,  but  it  would  seem  to  be 
worthy  of  some  degree  of  intelligent  research  on  the  part  of  both.  The 
presence  of  small  quantities  of  neutral  salts  (such  as  sodium  chloride, 
sodium  sulfate,  alumina,  calcium  sulfate,  iron,  etc.)  exert  a  distinctly 
inhibitory  effect  on  the  action  of  caustic  soda  in  kier  boiling  of  cotton.^ 

Trotman  and  Pentecost  ^  give  the  following  analyses  of  cotton 
properly  and  improperly  boiled-out  in  kiers: 


Properly  Boiled, 
Percent. 

Improperly  Boiled, 
Percent. 

Mineral  matter 

Free  fat 

0.05-0.75 
0.10-0.15 

Trace 
0.05-0.10 

1.00 
0.35-0.70 
0.25-0.50 
0.25-0.35 

Fat  as  soap 

Nitrogen 

The  relative  scouring  powers  of  different  alkalies  in  kier  boiling  is  also 
given,  the  loss  in  weight  of  the  cotton  being  taken  as  a  measure: 

Percent  Loss. 

Caustic  potash 5. 00 

"       soda 4.40 

Sodium  carbonate 3 .  70 

"       borate 2.80 

"       silicate 2.40 

According  to  Francke  ^  attempts  have  been  made  to  carry  out  kier  boil- 
ing and  bleaching  simultaneously,  using  sodium  peroxide.  A  sample 
of  Louisiana  cotton  with  a  fairly  thick  cuticle  was  used  in  j^arn  form. 
In  spite  of  prolonged  action  with  the  peroxide  in  moderately  strong  alkali 

^  See  Trotman,  Jour.  Soc.  Chem.  Ind.,  1910,  p.  249. 
^Jour.  Soc.  Chem.  Ind.,  1910,  p.  4. 
3  Text.  Berichte,  1922,  p.  108. 


536  CHEMICAL   PROPERTIES   OF   COTTON 

at  OO^-lOO"  C,  the  cuticle  was  not  completely  removed,  but  remained  as 
yellowish  spots  on  the  yarn.  With  fibers  having  a  thin  cuticle  a  good 
product  can  be  obtained,  but  even  then  there  is  too  much  non-cellulose 
left  and  fat  removal  is  incomplete.  Experiments  were  then  carried  out 
under  pressure,  the  cuticle  was  removed  and  almost  all  accompanying 
substances,  but  the  quantity  of  peroxide  used  was  too  great,  owing  to 
more  impurities  being  removed,  which  then  suffer  oxidation  at  the  expense 
of  the  peroxide.  No  formation  of  oxy cellulose  was  observed  in  either 
case.  If  the  bath  is  too  alkaline  oxycellulose  is  formed  and  vigorous 
oxygen  evolution  conditioned  by  catalysts  sets  in.  With  a  bath  much 
less  alkaline  than  kier  liquor,  oxygen  evolution  is  slow  and  i-egular,  but 
even  under  pressure  non-cellulose  removal  is  not  quite  complete  and 
yellowing  is  to  be  feared. 

In  the  United  States,  processes  for  the  simultaneous  boiling-out  and 
bleaching  of  cotton  have  been  commercially  introduced,  using  a  strongly 
alkaline  bath  of  sodium  peroxide.  The  method  has  chiefly  been  employed 
in  connection  with  the  bleaching  of  cotton  knit  goods  in  the  piece.  Sodium 
perborate  has  also  been  used  as  the  oxidising  agent  for  simultaneous 
boiling-out  and  bleaching  of  cotton.  This  oxidising  agent  is  less  sensitive 
to  decomposition  at  high  temperatures  than  sodium  peroxide,  but  it  is 
higher  in  price  and  not  so  commercially  available. 

12.  Action  of  Concentrated  Solutions  of  Caustic  Alkalies. — These 
have  a  peculiar  effect  on  cotton;  the  fiber  swells  up,  becomes  cylindrical 
and  semi-transparent,  while  the  interior  canal  is  almost  entirely  obliterated 
by  the  swelling  of  the  cell-walls.  There  is  a  marked  gain  in  weight  and 
strength,  while  the  affinity  of  the  cotton  for  coloring  matters  is  materially 
increased.  This  effect  was  first  noticed  by  John  Mercer  in  1844,  and  the 
reaction  forms  the  basis  of  the  modern  process  of  mercerising,  under 
which  title  a  more  complete  and  extensive  discussion  of  this  reaction  will 
be  found. 

When  cotton  is  heated  with  very  concentrated  caustic  soda  and  finally 
melted  with  an  excess  of  the  alkali  at  a  temperature  above  200°  C,  the 
cellulose  is  decomposed  with  the  formation  principally  of  oxalic  acid, 
acetic  acid,  formic  acid,  and  hydrogen. 

According  to  Schwalbe  ^  in  the  various  reactions  between  cotton  and 
alkalies  caustic  potash  appears  to  be  somewhat  less  energetic  than 
caustic  soda. 

Alkaline  solutions  prepared  from  the  hydrates  of  calcium,  barium  and 
strontium  have  an  action  on  cotton  similar  to  that  of  caustic  soda  or  caustic 
potash.  Milk  of  lime  is  largely  used  for  the  boiling-out  of  cotton  goods 
as  a  preparation  for  bleaching,  though  its  use  in  this  connection  is  more 
and  more  giving  way  to  caustic  soda.  At  high  temperatures  and  under 
^  Die  Chemie  die  Zellulose,  p.  52. 


ACTION  OF  CONCENTRATED  SOLUTION  OF  CAUSTIC  ALKALIES  537 

pressure,  as  in  kier  boiling,  the  hydrates  of  the  alkahne  earth  metals,  if 
in  the  presence  of  air,  also  have  a  deteriorating  influence  on  the  strength 
of  the  cotton. 

Solutions  of  sodium  sulfide  appear  to  have  no  immediate  tendering 
action  on  cotton,  even  at  a  boiling  temperature.  If  the  sodium  sulfide 
is  dried  into  the  fiber  after  about  six  weeks,  the  cotton  shows  a  loss  in 
strength  of  from  10  to  20  percent.  Also,  when  sodium  sulfide  is  dried 
into  the  fiber  at  100°  C,  the  tendering  amounts  to  from  10  to  20  percent. 
Cotton  containing  copper  sulfide  or  iron  sulfide  shows  no  appreciable 
amount  of  tendering. 

When  cotton  is  impregnated  with  sulfur  and  exposed  to  a  damp 
atmosphere  for  several  weeks,  its  tensile  strength  is  reduced  by  about 
one-half.  This  is  perhaps  due  to  the  oxidation  of  the  sulfur  into  sul- 
furous  and  sulfuric  acids. 

If  cotton,  or  other  forms  of  cellulose,  be  treated  with  a  concentrated 
solution  of  caustic  soda  to  which  a  small  amount  of  carbon  disulfide 
has  been  added,  the  fibers  swell  up,  become  disintegrated,  and  finally 
form  a  gelatinous  mass.  This  latter  is  soluble  in  a  large  amount  of  water, 
producing  a  very  viscous  solution,  technicall}^  known  as  viscose.^  From 
this  solution  hydrocellulose  may  be  precipitated  by  sulfurous  acid  gas,  as 
well  as  by  various  other  reagents.  Precipitation  also  occurs  by  simply 
allowing  the  solution  to  stand  for  some  time,  in  which  case  the  hydrated 
cellulose  separates  out  as  a  jelly-like  mass.  Viscose  has  received  several 
commercial  applications,  among  which  may  be  mentioned  more  especially 
the  use  of  its  solutions  for  the  preparation  of  filaments  of  artificial  silk, 
sausage  casings,  artificial  horse-hair,  staple  fiber  and  cellulose  films. 

Though  cotton  does  not  show  nearly  the  same  degree  of  affinity  for 
acids  and  alkalies  as  do  the  animal  fibers,  nevertheless  it  has  been  shown 
that  cotton  does  absorb  both  acids  and  alkalies  from  their  solutions, 
even  when  cold  and  dilute.  The  ratio  of  absorption  appears  to  be  3 
molecular  parts  of  acid  to  10  molecular  parts  of  caustic  alkali.  Vignon, 
by  a  study  of  the  thermochemical  reactions  of  cotton,  has  shown  that 
when  this  fiber  is  treated  with  acids  or  alkalies  a  liberation  of  heat  takes 
place  from  which  fact  it  would  appear  that  cotton  exhibits  in  some  degree 
the  properties  of  a  very  weak  acid  and  a  still  weaker  base.  Vignon  gives 
the  following  results  in  calories  per  100  grams  of  cotton: 

KOH.        NaOH.  HCl.  H2SO4. 

Rawcotton 1.30  1.08  0.65  0.60 

Bleached  cotton 2.27  2.20  0,65  0.58 

13.  Action  of  Oxidising  Agents;  Oxycellulose. — Strong  oxidising 
agents,  such   as    chromic  acid,  permanganates,  chlorine,  etc.,  in  concen- 

'  This  product  has  been  treated  more  fully  under  the  study  of  cellulose,  as  it  is 
prepared  technically  from  wood-pulp  rather  than  from  cotton. 


538  CHEMICAL   PROPERTIES  OF   COTTON 

trated  solutions,  readily  attack  cotton,  converting  it  into  oxycellulose. 
This  substance  appears  to  possess  an  increased  affinity  for  dyestuffs,  but 
it  is  of  a  structureless  and  brittle  nature,  hence  its  formation  greatly 
tenders  the  fiber. 

Scheurer  ^  has  studied  the  action  of  ammonium  persulfate  on  cotton 
when  steamed  and  found  that  this  compound  printed  in  the  proportion 
of  5  to  10  grams  per  liter  of  gum  tragacanth  thickening,  tenders  the  fiber 
to  the  extent  of  10  percent.  If  used  in  a  strength  of  20  grams  per  liter 
the  tendering  amounts  to  40  percent. 

According  to  Vignon,  there  is  a  considerable  difference  in  the  heat 
liberated  by  the  action  of  caustic  soda  on  cellulose  and  oxycellulose,  as 
follows: 

Cellulose 0 .  74  cals. 

Oxycellulose 1 .  30  cals. 

It  is  said  that  oxycellulose  is  indifferent  toward  the  tetrazo  dyestuffs; 
and,  in  consequence,  these  may  be  employed  for  the  purpose  of  detecting 
the  presence  of  oxycellulose  in  cotton  materials. 

It  may  readily  be  understood,  therefore,  that  in  the  processing  of  cotton 
materials  in  dyeing,  bleaching,  printing  and  finishing,  there  may  often 
arise  the  possibility  of  the  formation  of  oxycellulose,  as  in  the  processes 
of  boiling-out  in  the  kier,  bleaching  with  hypochlorites,  dyeing  with 
Aniline  Black,  discharging  with  chlorates  or  chromates,  the  dyeing  of 
Manganese  Brown,  and  similar  processes.  In  all  such  cases  particular 
care  must  be  taken  in  carrying  out  the  process  to  avoid  as  far  as  possible 
the  formation  of  oxycellulose.  According  to  Nastukoff  there  are  three 
modifications  of  oxycellulose,  which  he  terms  alpha-,  beta-,  and  gamma- 
oxycellulose.  These  are  distinguished  from  one  another  by  their  reaction 
with  ammonia  or  dilute  alkalies.  None  of  the  reactions  of  oxycellulose, 
however,  such  as  the  formation  of  a  golden-yellow  color  on  heating  with 
dilute  caustic  soda,  reduction  of  Fehling's  solution,  increased  affinity  for 
basic  dyes,  decreased  affinity  for  some  substantive  dyes,  formation  of 
furfural  by  distillation  with  hydrochloric  acid,  the  black  coloration  with 
Nessler's  reagent,  and  similar  reactions,  are  sufficiently  definite  to  be 
made  the  basis  of  an  accurate  qualitative  or  quantitative  determination 
of  oxycellulose.  It  is  doubtful  if  pure  oxycellulose  has  ever  been  pre- 
pared, the  product  always  being  a  mixture  with  unchanged  cellulose, 
hydrated  cellulose  and  hydroceUulose.  The  nearest  approach,  perhaps, 
to  a  quantitative  determination  of  the  alteration  the  cotton  cellulose  has 
undergone,  is  by  obtaining  the  "  copper  number  "  of  the  material,  which 
represents  really  the  amount  of  reducing  materials  present  that  will  react 
with  Fehling's  solution  to  precipitate  cuprous  oxide. 

1  Bull.  Soc.  Irid.  Mulh.,  1900,  August. 


ACTION  OF  OXIDISING  AGENTS;    OXYCELLULOSE  539 

According  to  Vignon  ^  oxj^cellulose  may  be  prepared  in  the  following 
manner:  Cotton  is  first  purified  by  successive  treatment  with  a  boiling 
solution  of  1  percent  sodium  carbonate,  boiling  solution  of  1  percent 
potassium  hydrate,  cold  solution  of  1  percent  hydrochloric  acid,  and 
cold  solution  of  sodium  carbonate.  The  fiber  is  then  well  washed  with 
water  and  alcohol,  and  dried.  About  30  grams  of  this  pmified  cotton  is 
placed  in  a  hot  solution  of  150  grams  of  potassium  chlorate  in  3000  cc.  of 
water,  and  125  cc.  of  hydrochloric  acid  is  gradually  added.  The  liquid  is 
heated  for  one  hour,  then  the  cotton  is  removed,  washed  with  water  and 
alcohol  and  dried.  The  oxycellulose  thus  obtained  is  in  the  form  of  short 
brittle  fibers  which  turn  j^ellow  when  heated  to  100°  C.  "UTien  boiled 
with  solutions  of  Safranine  and  Meth3'lene  Blue  a  gram  absorbs  0.007 
and  0.006  gram,  respectively,  whereas  ordinary  cotton  absorbs  0.001  and 
0.002  gram  per  gram  of  fiber. 

Oxj'cellulose  appears  to  have  the  formula  C18H26O16.  It  dissolves 
in  a  mixture  of  nitric  and  sulfuric  acids,  and  from  the  low  number  of 
hydroxyl  groups  reacting  with  the  nitric  acid,  it  maj'  be  concluded  that 
the  compound  is  both  a  condensed  as  well  as  an  oxidised  derivative  of 
cellulose.  Oxycellulose  is  soluble  in  dilute  solutions  of  the  alkalies,  and 
on  heating,  the  solutions  develop  a  deep  yellow  color.  When  warmed  with 
concentrated  sulfuric  acid  it  gives  a  pink  color  similar  to  that  of  mucic 
acid.  In  general  it  exhibits  a  close  resemblance  to  the  pectic  group  of  col- 
loidal carboh3"drates. 

It  is  probable  that  the  oxidation  products  of  cellulose  obtained  by 
different  means  do  not  all  give  the  same  oxycellulose,  or,  what  is  more 
probable,  the  oxj'celluloses  which  have  so  far  been  studied  are  perhaps 
niLxtures  of  various  different  bodies  which  have  not  yet  been  separated  and 
isolated. 

The  oxidation  of  normal  cellulose  may  be  effected  in  either  acid  or 
alkaline  liquors,  and  according  to  the  oxidising  agent  employed  and  the 
method  of  operation,  a  number  of  different  oxy celluloses  may  be  produced. 
All  of  them,  however,  possess  an  affinity  for  basic  dyes  and  yield  furfural 
when  distilled  with  hydrochloric  acid.  The  quantity  of  furfural  obtained 
serves  as  a  measure  of  the  amount  of  ox3'gen  contained  in  the  cellulose 
in  excess  of  that  required  to  satisfy-  the  formula  of  normal  cellulose 
(C6H10O5). 

Like  hydrocellulose,  oxj^cellulose  has  a  strong  affinity  for  water  and  is 
easily  hydrated.  Oxj^cellulose  maj'  be  distinguished  from  hydrocellulose 
by  its  reaction  with  Nessler's  reagent,  with  which  it  forms  a  dark  gray 
precipitate.  As  indicated  by  its  reactions  it  is  probable  that  oxycellulose 
is  characterised  by  the  presence  in  the  molecule  of  carbonyl  (CO)  and 
methox}'  (OCH3)  groups. 

'  Bull.  Soc.  Chim.,  1898,  p.  917. 


540 


CHEMICAL   PROPERTIES   OF   COTTON 


While  pure  cellulose  has  but  a  slight  reducing  action  on  Fehling's 
solution,  oxycellulose  like  hydrocellulose  causes  a  considerable  reduction; 
the  reaction  being  so  well  defined  that  it  may  be  employed  as  a  test  to 
determine  the  presence  of  oxycellulose  in  cotton  that  has  been  over- 
bleached.  The  determination  of  the  copper  nimiber,  or  copper  value,  of 
bleached  cotton  indicates  the  relative  degree  of  oxidation  of  the  fiber  and 
the  amounts  of  hydrocellulose  and  oxycellulose  formed;  and  as  the 
weakening  of  the  fiber  is  due  to  the  formation  of  these  two  bodies,  this 
test  serves  as  a  check  on  the  proper  control  of  the  bleaching  process. 
Hydrated  cellulose  does  not  reduce  Fehling's  solution,  nor  does  its  forma- 
tion cause  a  tendering  of  the  cotton. 

Vignon  ^  has  studied  the  osazones  of  oxycellulose  obtained  by  treating 
the  oxidation  products  of  cellulose  with  phenylhydrazine  and  acetic  acid 
for  thirty  minutes  at  80°  C.  The  results  are  summed  up  in  the  following 
table : 


Method  of  Preparation. 


Bleached  cotton 

Oxycellulose  by  chlorate  and  hydrochloric 

acid 

Oxycellulose  by  sodium  hypochlorite 

Oxycellulose  by  chromic  and  sulfuric  acid: 

48  hours  cold 

120  hours  cold 

1  hour  boihng 


Yield 
per  100 
Cellulose 


73.2 
1G.5 

85.0 
50.0 
45.0 


Nitrogen 
Fixed. 


0.448 

2.06 

0.87 

1.82 
2.00 
2.20 


Phenyl- 
hydrazine 
Fixed. 


1.727 

7.94 
3.37 

7.03 
7.71 

8.48 


Furfural. 


1.60 


09 
79 


3.00 
3.09 
3.50 


Moore  -  gives   the  effect   of  bleaching  powder  solutions  of  various 
strengths  on  cotton  yarns,  the  results  being  shown  in  the  following  table: 


Sample. 

Strength  of  Bleach 

Solution,  Grams  CI 

per  Liter. 

Tensile  Strength, 
Ounces. 

A 

15.3 

10.97 

B 

10.2 

11.77 

C 

7.65 

12.50 

D 

3.83 

12.50 

E 

2.55 

14.47 

F 

1.53 

12.82 

G 

0.00 

13.61 

I  Comptes  rendus,  1899,  p.  579.  -  Jour.  Soc.  Dyers  &  Col.,  1915,  p 


183. 


ACTION  OF  OXIDISING  AGENTS;   OXYCELLULOSE  541 

Knaggs^  gives  the  following  test  for  oxycellulose :  Take  a  piece  of 
cotton  cloth  which  has  been  spotted  with  some  oxycellulose-producing 
substance,  such  as  bleaching  powder,  and  after  the  oxycellulose  has  been 
formed,  wash  it  with  acid  and  then  many  times  with  water,  dye  it  with  a 
strong  shade  of  Congo  red,  and  then  place  the  cloth  in  sufficient  acid  to 
get  a  blue  color.  The  cotton  is  now  carefully  washed  with  a  limited 
amount  of  water  until  the  ordinary  cotton  has  a  good  red  shade,  when 
the  oxycellulose  spot  will  appear  as  a  black  spot  on  the  red  ground.  At 
this  stage  mercerised  cotton,  if  present,  appears  red ;  hydrocellulose  cannot 
be  mistaken  for  the  oxycellulose  in  this  test. 

Schwalbe  and  Robinoff  -  have  shown  that  cellulose  which  has  been 
chemically  affected  by  bleaching  undergoes  hydrolysis  when  heated  with 
water  to  high  temperatures.  It  was  found  that  in  bleaching  cotton  with 
hypochlorite  solutions  followed  by  souring  with  hydrochloric  acid,  the 
formation  of  oxycellulose  is  promoted  by  the  use  of  low  strengths  of  acid. 
In  addition  to  determinations  of  the  solubility  of  the  cellulose  in  dilute 
caustic  soda  the  so-called  "  mucilage  values  "  (the  weight  of  the  flocculent 
matter  precipitated  by  alcohol  after  neutralisation  of  the  alkahne  extract) 
were  also  ascertained.  Above  150°  C.  the  mucilage  value  was  much 
larger  and  consequently  this  temperature  is  stated  as  the  "  critical  tem- 
perature "  for  cotton  cellulose.  A  determination  of  the  copper  value  of 
cotton  treated  with  hot  caustic  soda  solution  shows  that  a  concentration 
of  4  percent  of  alkali  in  the  case  of  cold  lyes  was  the  most  destructive.  The 
products  of  hydrolysis  formed  by  the  action  of  1  to  2  percent  sodium 
hydroxide  solutions  appeared  to  undergo  decomposition  above  100°  C. 
there  being  a  decrease  in  the  copper  value.  The  decrease  in  the  hydrolysis 
effected  by  lyes  of  5  percent  strength  and  over  is  probably  due  to  the 
beginning  of  mercerisation  or  hydration.  In  this  case  American  cotton 
gives  a  much  higher  copper  value  than  Egyptian  cotton. 

A  method  of  determining  the  amount  of  copper  reduced  in  the  Fehling's 
solution  by  oxycellulose  has  been  devised  by  Schwalbe.^  About  3  grams  of 
air-dried  cotton  are  boiled  for  fifteen  minutes  under  a  reflux  condenser 
with  100  cc.  of  Fehling's  solution  and  200  cc.  of  water,  the  flask  being 
constantly  shaken.  The  hot  liquid  is  then  filtered,  the  residue  washed 
with  boiling  water,  and  heated  on  the  water-bath  for  fifteen  minutes  with 
30  cc.  of  6.5  percent  nitric  acid,  and  the  dissolved  copper  is  finally  deter- 
mined, preferably  by  the  electrolytic  method.^  By  this  means  the  follow- 
ing copper  values  were  obtained : 

1  Jour.  Soc.  Dyers  &  Col,  1908,  p.  112. 

2  Zeit.  angew.  Chem.,  1911,  p.  256. 

3  Berichte,  1907,  pp.  1347  and  4523. 

''  Hiisslund  (Pajrier-Fabrik.,  1909,  p.  301)  has  sugsested  simplifying  Schwalbe's 
method  of  dete- mining  the  copper  number.     Instead  of  determining  the  copper  elec- 


542  CHEMICAL  PROPERTIES   OF   COTTON 

Surgical  cotton  wool 1 . 6-1 . 8 

Bleached  mercerised  yarn 1 . 6-1 . 9 

Artificial  silk  (Glanzstoff) 11 

Hydrocellulose 5  •  2-5 . 8 

Parchment  paper 4.2 

Bleached  sulfite  wood  pulp 3.9 

Over-bleached  wood  pulp 19.3 

Oxycellulose  (bleaching  powder  on  filter-paper) 7.9 

Bleached  cotton  rag 6.5 

There  have  been  previously  described  by  a  number  of  investigators 
various  chemical  reactions  which  will  more  or  less  completely  identify  and 
describe  oxycellulose.  The  detection  of  this  alteration  product  of  cellulose 
is  especially  valuable  in  the  case  of  cotton  bleaching  and  mercerising,  and 
in  many  cases  it  indicates  where  faults  are  to  be  found  in  processes  of  textile 
finishing.  It  has  been  pointed  out,  however,  that  scarcely  any  of  these 
previously  described  tests  are  capable  of  clearly  distinguishing  between 
oxycellulose  and  hydrocellulose,  and  this  distinction  is  sometimes  of  con- 
siderable importance.  The  experimental  evidence  which  is  available 
indicates  that  the  different  forms  of  oxycellulose  and  hydrocellulose  are 
probably  to  be  considered  as  absorption  compounds  of  peptised  cellulose, 
and  are  the  products  resulting  from  the  hydrolysis  of  the  cellulose  fiber. 
The  dyeing  properties  of  the  cotton  fiber  depend  mainly  upon  the  colloidal 
condition  of  the  cellulose  portion,  and  the  reducing  properties  of  the  fiber 
are  due  to  the  products  of  hydrolysis  brought  about  by  the  action  of 
various  chemical  operations.  It  is  probable  that  the  absorbed  reducing 
substances  are  of  the  nature  of  an  aldehyde  in  hydrocellulose  and  of  the 
nature  of  an  acid  in  oxycellulose.  For  the  purpose  of  detecting  the  pres- 
ence of  either  of  these  reducing  substances  (oxycellulose  or  hydrocellulose) 
in  cotton  fabrics  it  is  recommended  to  prepare  a  reagent  by  adding  a  solu- 
tion of  silver  nitrate  to  one  of  sodimn  thiosulfate  with  vigorous  stirring, 
and  then  adding  a  solution  of  caustic  soda  so  as  to  obtain  a  liquid  containing 
1  percent  of  silver  nitrate,  4  percent  of  sodium  thiosulfate,  and  4  percent  of 
sodium  hydroxide.  If  the  fabric  to  be  examined  is  boiled  in  this  solution  or 
padded  with  it  and  then  steamed,  the  portions  containing  oxycellulose  will 
become  stained.  The  effect  will  be  enhanced  if  the  material  is  first  heated 
with  a  1  percent  solution  of  phenylhydrazine  in  glacial  acetic  acid  and  then 
washed  with  dilute  acetic  acid  and  subsequently  treated  as  above  with 
the  silver  solution. 

14.  Cellulose  Peroxide. — Cotton  and  linen  fabrics  which  have  been 
bleached  and  acidified,  without  the  subsequent  use  of  an  antichlor,  some- 

trolytically,  the  copper  oxide  is  dissolved  in  a  solution  of  ferrous  sulfate  in  sulfuric 
acid,  and  then  titrated  with  potassium  permanganate  See  also  Betrand,  Bull.  Soc. 
Chem.,  1906,  p.  1285,  and  Freiberger,  Zeil.  angew.  Chem.,  1917,  p.  121. 


ACTION  OF  METALLIC  SALTS  543 

times  retain  the  property  characteristic  of  "  active  oxygen  "  by  liberating 
iodine  from  potassium  iodide  for  a  much  longer  time  than  is  consistent 
with  the  survival  of  traces  of  residual  hypochlorites.  Cross  and  Bevan  ^ 
call  attention  to  a  case  where  cotton  cloth  was  bleached,  soured,  and 
washed  under  normal  conditions,  and  yet  retained  an  acid  reaction  and 
oxidising  properties  toward  potassium  iodide  even  after  exhaustive  washing 
with  distilled  water.  The  oxidising  property  was  rapidly  destroyed  by 
boiling  with  water  or  by  treatment  with  "  antichlor."  Cross  and  Bevan 
assume  this  character  to  be  due  to  the  formation  of  cellulose  peroxide. 
Ditz  -  has  observed  that  the  same  phenomenon  can  be  produced  by  grad- 
ually heating  cotton  with  an  acid  solution  of  ammonium  persulfate  up  to  a 
temperature  of  80°  C. 

Bumcke  and  Wolff enstein  ^  have  shown  that  hydrogen  peroxide 
reacting  with  cotton  does  not  produce  oxycellulose  but  brings  about  an 
hydrolysis  with  the  formation  of  a  product  they  call  hydralcellulose.  This 
is  obtained  by  allowing  strong  hydrogen  peroxide  (60  percent)  to  act  on 
cotton  for  ninety  days,  when  the  fiber  will  be  completely  converted  into  a 
white  powder.  It  reduces  Fehling's  solution  vigorously  and  is  apparently 
of  an  aldehyde  nature  as  it  also  reduces  ammoniacal  silver  solution.  By 
boiling  with  a  10  percent  solution  of  caustic  soda  hydralcellulose  is  con- 
verted partly  into  cellulose  and  partly  into  acid  cellulose,  which  though 
having  no  reducing  properties,  is  soluble  in  caustic  soda  solution  and  in 
strong  hydrochloric  acid. 

15.  Action  of  Metallic  Salts. — In  its  action  toward  various  metallic 
salts  cotton  is  very  neutral,  thereby  differing  considerably  from  both 
wool  and  silk.  If  the  salts,  however,  are  present  in  a  very  basic  condition, 
cotton  is  capable  of  decomposing  them  and  looselj''  fixing  the  metallic 
hydroxide.  When  cotton,  for  instance,  is  digested  with  a  solution  of 
barium  hydrate,  or  with  the  basic  salts  of  such  metals  as  lead,  zinc,  copper, 
tin,  aluminium,  iron,  chromium,  cobalt,  nickel,  manganese,  molybdenum, 
tungsten,  etc.,  the  fiber  absorbs  an  appreciable  quantity  of  the  basic  oxide 
though  very  much  less  than  is  the  case  with  the  animal  fibers. 

Michaelis'*  states  that  cotton  has  the  property  of  precipitating,  by 
mechanical  surface  attraction  (adsorption),  mordants  such  as  salts  of 
aluminium,  iron,  chromium,  zinc,  with  weak  acids,  which  on  treatment 
in  the  dyeing  vat  form  between  the  molecules  of  the  fiber  insoluble  com- 
pounds with  the  dyestuffs. 

Liechti  and  Suida  °  show  the  influence  of  the  basicity  of  aluminium 
salts  on  their  absorption  by  cotton.  Solutions  containing  200  grams  per 
liter  of  the  respective  sulfates  were  used,  as  follows: 

1  Zeit.  angew.  Chem.,  1906,  p.  2101.    '  Berichle,  1899,  p.  2493. 

2  Chem.  Zeit.,  1907,  p.  833.  ^  Pfltiger's  Arch. ges. Physiol. ,wo\.97,pp.QS4-M0. 

6  Jour.  Soc.  Chem.  lad.,  1883,  p.  537. 


544  CHEMICAL  PROPERTIES  OF  COTTON 

^  ...        f  a  u"  +  Percent  AI2O3 

Composition  01  feuliate.  . ,       ,     , 

Absorbed. 

Al2(S04)3-18H20  (normal) 12.9 

A1(S04)  •  (0H)6 51 .0 

Al4(S04)3-(OH)4 58.7 

Al2(S04)  •  (0H)4 — 

The  last  dissociated  too  rapidly  for  experimentation.  The  fact  that  a 
salt  is  a  basic  one  is  not  any  indication  that  it  will  act  as  a  mordant;  the 
basic  chlorides  and  oxychlorides  of  almninium  are  not  mordants. 

Haller  ^  has  investigated  the  action  of  mordants  on  cotton  from  the 
point  of  view  of  the  adsorptive  capacity  of  cellulose.  Cotton  cellulose  is 
considered  as  being  in  the  form  of  a  gel,  both  as  raw  cotton  and  after 
purification  with  alkali.  In  the  experiments  the  cotton  was  left  for 
forty-eight  hours  in  the  solution  of  the  salt  concerned.  The  amount  of 
metallic  oxide  was  then  determined  in  the  filtrate  and  referred  to  the 
amount  of  cotton  used.  It  was  then  possible  to  find  the  relation  between 
the  purity  of  the  cotton  and  its  adsorptive  capacity.  Indian  cotton,  for 
instance,  which  can  be  wet  only  with  difficulty,  adsorbs  salts  (aluminium 
sulfate,  aluminium  acetate,  and  lead  acetate)  the  least;  the  reverse  being 
true  of  both  American  and  Egyptian  cotton.  Of  the  three  salts,  lead 
acetate  was  adsorbed  to  the  greatest  extent,  with  aluminium  acetate  a 
negative  adsorption  was  noticed;  that  is,  the  cotton  took  up  nothing  from 
this  solution,  but  on  the  other  hand,  gave  up  certain  of  its  mineral  constitu- 
ents to  the  solution,  the  more  highly  purified  the  cotton  the  greater  was  this 
loss.  This  phenomenon,  however,  may  be  explained  by  assuming  that 
the  cotton  fiber  does  adsorb  some  of  the  aluminium  compound  but  also 
gives  up  more  of  its  own  mineral  matter,  in  consequence  of  which  the 
treated  cotton  shows  less  ash  than  at  first,  and  therefore  the  negative 
adsorption  is  only  apparent.  In  the  case  of  lead  acetate  only  raw  cotton 
will  adsorb  and  hold  fast  the  lead  salt  even  to  subsequent  washing;  with 
purified  cotton  (boiled-out  and  bleached)  the  lead  salt  at  first  adsorbed  may 
be  completely  washed  out  again.  Schwalbe  and  Becker  ^  have  shown  that 
both  hydrocellulose  and  oxycellulose  take  up  more  alumina  than  cellulose 
itself.  These  discussions,  though  seemingly  of  only  theoretical  interest,  have 
considerable  bearing  on  the  mordanting  of  cotton  and  the  sizing  of  paper. 

Salts  of  stannic  acid  (sodium  stannate)  are  also  absorbed  by  cotton 
to  quite  a  marked  degree.  In  this  instance,  stannic  acid  appears  to  act 
much  in  the  same  manner  as  tannic  acid. 

Many  salts,  especially  those  of  an  acid  nature,  will  tender  the  cotton 
fiber,  probably  due  to  the  liberation  and  drying-in  of  the  acid.  Con- 
sequently, such  salts  should  be  avoided  or  used  very  carefully  with  cotton, 
and  any  excess  should  be  thoroughly  eliminated  by  subsequent  washing 
before  the  material  dries.  Magnesium  chloride  is  largely  used  in  the 
preparation  of  finishes  for  cotton  goods,  and  tendering  of  the  fiber  may 
1  Chem.  Zeii.,  1918,  p.  597.  2  ZeU.  anqew.  Chem.,  1919,  pp.  265  and  355. 


ACTION   OF   METALLIC   SALTS  545 

occur  if  fabrics  containing  this  salt  are  subjected  to  high  temperatures 
such  as  experienced  in  drying  over  hot  rolls. 

The  following  facts  have  been  determined  with  reference  to  the  use  of 
magnesium  chloride  on  cotton  goods: 

(1)  An  aqueous  solution  of  magnesium  chloride  does  not  begin  to  decompose  until 
a  temperature  of  223°  F.  is  reached,  neither  alone  nor  in  the  presence  of  an  excess 
of  air,  not  in  steam,  nor  in  the  presence  of  cellulose,  nor  in  admixture  with  other 
ordinary  finishing  agents. 

(2)  The  amount  of  hydrochloric  acid  generated  up  to  a  temperature  of  480°  F.  is 
quite  small,  aggregating  only  about  2  per  cent  of  the  whole. 

(3)  The  deterioration  of  cotton  finished  with  magnesium  chloride  does  not  take 
place  below  223°  F.  Such  cotton  may  therefore  be  safely  treated  with  steam  at  the 
atmospheric  pressure. 

(4)  Cotton  finished  with  magnesium  chloride  should  not  be  subjected  to  high 
temperatures,  especially  such  treatment  should  not  be  prolonged.  The  limiting  tem- 
perature for  the  drying  of  such  material  should  be  212°  F. 

(5)  If  a  temperature  of  212°  F.  in  drying  is  not  exceeded,  magnesium  chloride  may 
be  employed  without  danger  in  the  finishing  of  cotton  fabrics.  It  should  not  be  used, 
however,  if  such  material  is  to  be  subjected  to  steam  under  pressure  or  to  ironing. 

Zinc  chloride  is  sometimes  employed  in  sizing  compounds  used  on 
cotton  warps  and  it  has  been  found  when  such  material  is  singed  or 
subjected  to  high  temperatures  the  fiber  becomes  tendered.  Flintoff^ 
has  investigated  this  matter  and  has  come  to  the  conclusion  that  the 
tendering  action  is  not  so  much  due  to  the  formation  of  free  hydrochloric 
acid  as  it  is  to  the  formation  of  a  hydrated  cellulose  zinc  oxide  compound. 
He  showed  by  experiment  that  if  cotton  were  treated  with  zinc  chloride 
solution  and  steamed,  the  fibers  became  swollen  and  translucent,  and  in 
many  respects  resembled  mercerised  cotton. 

In  studying  the  effects  of  metallic  salts  on  cotton  it  is  important  to 
distinguish  between  the  action  of  acid,  neutral,  basic  and  alkaline  salts. 
Acid  salts  are  those  which  readily  become  dissociated  with  the  liberation 
of  free  acid,  especially  when  in  solution  or  when  heated.  Such  mineral 
salts  react  in  a  manner  very  similar  to  free  mineral  acids,  only  not  to  the 
same  degree.  They  tend  to  destroy  the  cellulose  of  the  cotton  with  the 
formation  of  hydrocellulose,  and  a  consequent  weakening  of  the  fiber. 
Alum,  aluminium  chloride,  magnesium  chloride,  sodium  bisulfate  and 
stannic  chloride  are  examples  of  acid  salts.  Neutral  salts  appear  to 
exert  little  or  no  action  on  cellulose  or  cotton  under  ordinary  conditions; 
such  salts  are  common  salt,  glaubersalt,  magnesium  sulfate  and  the  like. 
Basic  salts  are  those  in  which  the  metallic  base  dominates  in  strength 
the  acid  radical  to  which  it  is  attached,  so  that  in  solution  the  salt  tends 
to  liberate  its  base.  Many  metallic  salts  are  of  this  character,  especially 
when  the  combined  acid  is  an  organic  one,  such  as  acetic,  lactic,  tartaric, 
and  the  like.  The  acetate  of  iron  or  aluminium,  for  example,  is  rather 
easily  dissociated  with  the  liberation  of  the  free  metallic  hydrate  or  oxide. 
2  Jour.  Soc.  Dyen  &  Col.,  1899,  p.  154. 


546 


CHEMICAL  PROPERTIES  OF  COTTON 


The  reaction  of  such  salts  with  cotton  is  to  undergo  a  slight  degree  of  disso- 
ciation so  that  the  fiber  takes  up  a  small  amount  of  the  metallic  hydrate. 
The  action  of  cotton  in  this  respect  however,  is  not  nearly  as  strong  as 
with  wool  or  silk,  and  on  this  account  it  is  not  possible  to  mordant  cotton 
in  the  same  manner  or  as  readily  as  the  other  two  fibers  mentioned. 
Alkaline  salts  include  such  bodies  as  sodium  carbonate  (soda  ash)  and 
sodium  sulfide.  In  these  cases  the  combined  acid  radical  is  so  weak  as 
compared  with  the  basic  nature  of  the  metal,  that  the  salt  exhibits  the 
properties  of  a  strong  alkali,  and  the  reactions  of  these  with  cotton  have 
already  been  considered. 

Barium  chlorate  may  be  employed  for  treating  cotton  which  is  sub- 
sequently to  be  destroyed  for  pattern  effects.  Lace  and  embroidery 
effects  are  obtained  by  making  these  effects  on  a  base  of  cotton  cloth  which 
has  been  treated  with  a  solution  of  barium  chlorate  and  then  dried  at  a  low 
temperature.  This  salt  does  not  injure  the  needles  used  in  the  embroidery, 
and  when  the  fabric  is  heated  for  a  short  time  at  320°  F.  it  becomes  dis- 
integrated and  may  be  brushed  away  from  the  lace  or  embroidery. 

Opaline  and  plastic  effects  on  fabrics  are  given  by  precipitates  from 
sodium  tungstate  and  barium  chloride  solutions  in  the  hydrosulfite  bath. 
The  method  is  particularly  successful  for  mercerised  cotton. 

The  action  of  various  salts  heated  in  contact  with  cotton  is  given  by 
Ford  and  Pickles.^     The  results  are  shown  in  the  following  table: 


Salts  Used  in  Normal  Solution. 


Sodium  chloride 

Sodium  sulfate 

Magnesium  chloride 

Zinc  chloride 

Zinc  chloride  with  sodium  chloride 

Magnesium  chloride  with  sodium  chloride 
Magnesium  chloride  with  zinc  chloride .  .  . 
Magnesium  chloride  with  sodium  sulfate . 
Magnesium  sulfate  with  sodivun  chloride . 

Magnesium  sulfate 

Water  alone 


After  Padding,  Drying  Below 
50°  C.  and  Treating  to  100°  C. 


Tensile  Strength, 

Elongation, 

Ounces. 

Percent. 

11.69 

5.63 

10.94 

5.62 

9.11 

5.05 

8.19 

4.88 

9.81 

4.83 

10.38 

5.68 

9.12 

5.28 

11.66 

6.00 

10.84 

5.75 

11.40 

5.65 

10.73 

5.9 

Scheurer^  from  experiments  with  iron  mordants  on  cotton  finds  that 
after  aging  for  twelve  hours  at  36  to  40°  C.  a  tendering  of  15  percent  is 
noticed,  and  after  dunging  the  average  tendering  is  25  percent. 

The  rapid  disintegration  of  textile  fabrics  when  exposed  to  sea  water 
1  Jour.  Soc.  Dyers  &  Col,  1915,  p.  257.  "  Bull.  Soc.  Ind.  Mulh.,  1893. 


ACTION  OF  METALLIC  SALTS 


547 


is  well  known.  Under  the  condition  of  complete  immersion  most  textile 
fibers  become  completely  rotted  in  three  to  five  weeks.  Experiments 
have  pointed  to  the  conclusion  that,  in  the  case  of  cotton,  the  change 
brought  about  is  in  some  way  conditioned  by  the  reactivity  of  the  hydroxyl 
groups  in  the  cellulose  molecule.  This  result  has  led  to  investigation  of 
acetate  silk  made  from  cellulose  triacetate.  After  four  months'  immersion 
in  sea  water  no  appreciable  change  had  taken  place,  which  fact  has  caused 
the  acetate  silk  to  be  recommended  for  marine  biological  use.  Stated 
briefly,  the  results  of  the  investigations  are  as  follows : 

(1)  Fabrics  of  cotton  and  silk  are  destroyed  by  immersion  in  sea  water  for  three 
weeks,  wool  lasting  somewhat  longer. 

(2)  The  destructive  action  has  been  shown  in  the  case  of  cellulose  to  be  due  to 
micro-organisms  and  not  to  oxygen,  hght,  or  the  salts  present. 

(3)  In  its  nature  it  resembles  the  "mechanical"  breakdo^\Ti  of  cotton  sometimes 
observed  under  the  "beetling"  process. 

(4)  If  cotton  is  acetylated  to  the  mono-acetate  stage  so  that  its  structural  quaUties 
are  preserved,  the  resulting  material  is  very  resistant  to  sea  water. 

(5)  Cellulose  acetate  silk  has  proved  capable  of  withstanding  the  action  of  sea 
water  for  months. 

Hlibner  and  Malwin  ^  have  studied  the  effect  of  various  metallic  salt 
solutions  and  finishing  compounds  on  the  "  ripping  "  strain  of  cotton 
fabrics.  Tests  were  made  both  with  1  percent  solutions  and  with  satu- 
rated solutions.  The  following  table  gives  the  results  of  the  tests  in  terms 
of  the  mean  figures  for  the  warp  and  filling : 


RippiQg  Strain. 

Tensile  Strain. 

1  Percent  Solutions. 

1 

Air-dry. 

100°  C. 

120°  C. 

Air-dry. 

100°  C. 

120°  C. 

Original  fabric 

100.0 

95.4 

98.3 

100 

101.9 

102.2 

Calcium  chloride .... 

103.3 

97.9 

97.6 

96.5 

96.7 

87.8 

Magnesium  chloride  . 

102.0 

99.9 

100.1 

95.8 

93.5 

96.6 

Zinc  chloride 

98.1 

93.3 

95.1 

103.7 

100.8 

91.6 

Sodium  sulfate 

107.0 

111.8 

106.4 

96.8 

96.9 

98.5 

Sodium  sulfate 

101.8 

99.9 

106.5 

94.7 

94.1 

94.4 

Sodium  sulfide 

105.6 

104.7 

106.8 

103.0 

95.6 

93.9 

Boric  acid 

100.7 
104.8 

96.2 
107.2 

85.5 
94.2 

96.3 
94.1 

91.9 
90.7 

88.1 

Borax 

93.7 

Sodium  chloride 

113.4 

115.0 

101.3 

99.4 

98.3 

97  5 

Sodium  carbonate .  .  . 

112.1 

108.0 

100.1 

99.0 

97.6 

98.8 

Sodium  phosphate . .  . 

110.6 

110.8 

112.1 

95.2 

104.6 

103.0 

Sodium  acetate 

109.3 

114.0 

100.9 

103.8 

94.9 

97.8 

Sodium  stannate .... 

74.0 

76.4 

78.6 

105.0 

94.1 

99.3 

Starch  solution 

112.4 

117.5 

102.6 

96.9 

89.3 

86.1 

Soap  solution 

136.9 

146.2 

128.1 

94.6 

91.4 

90.9 

1  Jour.  Soc.  Chem.  Ind..  1923,  p.  66. 


548 


CHEMICAL  PROPERTIES  OF  COTTON 


It  would  seem,  therefore,  that  the  effect  of  1  percent  sohitions  of 
these  salts  on  the  tensile  strain  is  negligible;  the  same  is  also  true  of  the 
ripping  strain  with  the  single  exception  of  sodium  stannate,  and  this  is 
such  an  anomalous  exception  that  we  are  inclined  to  believe  that  there 
must  be  some  error  in  the  results  given. 


Saturated  Solutions. 


Calcium  chloride 

Magnesium  chloride .  .  .  . 
Zinc  chloride  (110°  Tw.) 

Sodium  sulfate 

Sodium  sulfite 

Sodium  sulfide 

Boric  acid 

Borax 

Sodium  chloride 

Sodium  carbonate 

Sodium  phosphate 

Sodium  acetate 

Sodium  stannate 


Ripping  Strain. 


Air-dry. 


64.0 
66.1 
70.1 
63.8 
74.1 
56.7 
89.7 
85.. 5 
76.8 
65.2 
99.7 
69.8 
64.6 


100°  C. 


47.2 
62.1 
31.0 
60.3 
67.6 
39.6 
80.6 
75.2 
74.0 
61.4 
100.8 
53.8 
51,5 


Tensile  Strain. 


Air-drv. 


73.6 
89.9 
84.4 
96.8 
92.9 
70.7 
88.8 
86.3 
98.0 
90.1 
94.7 
103.1 
98.2 


100"  C. 


63.8 
74.6 
56.1 
91.7 
90.4 
72.5 
75.1 
85.0 
93.3 
88.3 
89.4 
99.2 
93.1 


From  this  it  will  be  seen  that  the  effect  of  saturated  solutions  of  salts 
in  many  cases  is  very  marked,  the  greatest  reduction  in  the  ripping 
strain  being  produced  l^y  zinc  chloride,  with  sodium  sulfide  next  in  order. 
Sodium  phosphate  solution  has  practically  no  effect  on  the  ripping  strain. 

16.  Weighting  of  Cotton  Yams. — Cotton  yarn  may  be  weighted  to  a 
considera])lc  extent,  when  d^yod  with  the  direct  colors,  by  adding  mag- 
nesium sulfate  (Epsom  salt)  to  the  dye  bath,  together  with  a  small 
quantity  of  dextrin.  Owing  to  danger  of  imperfections  in  the  color,  such 
as  imevenness  and  cloudiness,  it  is  perhaps  better  to  use  a  separate  bath 
after  the  dyeing  for  the  purpose  of  weighting.  This  will  be  especially 
true  if  it  is  desired  to  weight  to  any  considerable  extent.  The  following 
process  is  a  typical  example  of  weighting  cotton  yarn  which  has  been  dyed 
with  direct  colors.  For  100  lbs.  of  cotton  yarn  use  a  bath  containing  about 
160  gallons  of  water;  add  100  lbs.  of  magnesium  sulfate,  15  lbs.  of  dex- 
trin, and  2  lbs.  of  glycerol.  Have  the  temperature  of  the  bath  at  about 
120°  F.  The  cotton  yarn  is  entered  into  this  bath  and  turned  for 
twenty  minutes,  or  until  the  fiber  is  thoroughly  saturated  with  the 
solution.  It  is  then  removed,  hydroextracted  and  dried.  Such  a  treat- 
ment as  this  will  give  a  weighting  of  about  10  to  12  percent  to  the  cotton 
yarn.  The  bath  is  by  no  means  exhausted,  and  may  be  freshened  up  by 
the  addition  of  a  small  amount  of  magnesium  sulfate  and  dextrin  till 


WEIGHTING  OF  COTTON  YARNS  549 

it  is  brought  back  to  the  same  hydrometer  test  as  at  first,  and  succeeding 
lots  of  cotton  may  be  treated  as  above.  The  glycerol  is  added  for  the 
purpose  of  preventing  the  weighting  material  from  giving  the  fiber  a  stiff 
handle.  Instead  of  emplojang  glycerol  a  small  amount  of  Turkey-red 
oil  or  soluble  softener  may  be  used.  Soaps,  however,  cannot  be  employed 
in  this  connection,  as  they  would  be  precipitated  by  the  magnesium  salt 
present,  forming  an  insoluble  metallic  soap.  By  this  process  of  weighting, 
yarn  which  is  dyed  in  even,  bright  and  delicate  colors  may  be  successfully 
treated,  as  the  weighting  material  does  not  add  any  color  of  itself  to  the 
yarn.  Of  other  metallic  salts,  zinc  sulfate  has  also  been  suggested  as 
weighting  material,  as  its  presence  furthermore  is  highly  antiseptic  and 
prevents  the  growth  of  mildew  or  the  origin  of  fermentation  in  the  cotton 
which  contains  it.  Zinc  sulfate,  however,  is  more  expensive  than  mag- 
nesium sulfate  and  is  more  or  less  poisonous  in  character,  hence  would  be 
objected  to  in  the  majority  of  instances.  Barium  chloride  might  also 
be  employed  for  weighting,  but  it  is  more  expensive  than  magnesium 
sulfate,  and  furthermore  barium  salts  are  also  poisonous.  Calcium 
chloride  is  another  metallic  salt  the  use  of  which  has  been  suggested  for 
weighting  cotton  yarns,  but  this  substance  is  so  highly  hygroscopic  that 
it  is  difficult  to  understand  how  it  could  be  used  with  advantage  on  cotton 
yarns,  as  it  would  absorb  moisture  to  such  an  extent  that  when  present 
in  any  considerable  quantity  on  the  yarn  it  would  cause  the  latter  to 
become  damp  and  sticky. 

This  method  of  weighting  yarns  does  not  furnish  a  weighting  material 
which  is  insoluble  in  water,  hence  the  weighting  would  be  easily  removed 
if  the  yarn  or  the  material  into  which  it  is  to  be  manufactured  were 
washed  with  watei*  or  scoured  with  soap.  Furthermore,  yarn  weighted 
in  this  manner  with  magnesium  sulfate,  if  scoured  subsequently  in  the 
cloth  with  soap  solutions,  would  furnish  a  very  defective  material,  as  the 
magnesium  soap,  which  would  be  formed  by  the  action  of  the  soap  with 
the  magnesium  sulfate,  is  insoluble  in  water  and  is  of  sticky  nature,  so 
that  it  is  very  difficult  to  remove  completely  from  the  fiber.  This  will 
naturally  lead  to  bad  defects  if  a  subsequent  scouring  operation  is  necessary. 

In  case  the  cotton  to  be  weighted  is  dyed  in  black  or  in  dull,  heavy 
shades,  such  as  blues  or  violets,  a  considerable  degree  of  weighting  may  be 
obtained  by  treating  the  dyed  yarn  alternately  with  baths  of  sumac 
extract  and  pyrolignite  of  iron.  This  will  cause  the  formation  on  the 
fiber  of  an  insoluble  tannate  of  iron,  and  the  weighting  thus  obtained  is 
of  a  permanent  character.  This  tannate  of  iron,  however,  is  of  a  black 
color,  and  so  has  the  effect  of  darkening  and  dulling  the  color  which  may 
be  dyed  on  the  yarn  in  the  first  place.  The  tannic  acid  of  the  sumac 
and  the  iron  salt  have  the  effect  of  making  the  fiber  very  harsh  if  any 
considerable  amount  of  these  materials  is  fixed  on  the  cotton,   conse- 


550  CHEMICAL  PROPERTIES  OF  COTTON 

quently  the  amount  of  weighting  in  this  case  is  rather  hmited.  It  is 
possible,  however,  by  this  means  to  obtain  a  weighting  of  about  5  percent 
without  very  materially  injuring  the  quality  of  the  yarn,  if  a  small  amount 
of  glycerol  or  oil  is  employed  for  the  purpose  of  softening  the  fiber  and  thus 
in  some  degree  neutralising  the  harshening  effect  of  the  weighting  materials. 

17.  Action  of  Coloring  Matters. — In  its  behavior  toward  coloring  matters 
cotton  differs  most  markedly  from  the  animal  fibers.  Of  the  natural  dyestuffs, 
only  a  few  color  the  cotton  fiber  without  a  mordant;  with  the  coal-tar 
colors,  cotton  exhibits  no  affinity  for  most  of  the  acid  or  basic  dyes,  and 
these  can  only  be  applied  on  a  suitable  mordant.  The  substantive  colors, 
however,  are  readily  dyed  on  cotton,  in  a  direct  manner,  and  since  their  intro- 
duction the  methods  of  cotton  dyeing  have  been  practically  revolutionised. 

There  has  been  much  discussion  as  to  whether  the  phenomena  of 
dyeing  with  reference  to  cotton  are  of  a  physical  or  chemical  nature. 
From  the  view-point  of  colloidal  chemistry  it  would  seem  that  the  process 
of  dyeing  is  one  of  adsorption,  and  the  principal  force  operating  is  capillary 
action.^  Unlike  the  animal  fibers,  cotton  does  not  possess  groups  of  a 
very  distinctly  active  chemical  nature;  that  is  to  say,  it  cannot  be  said 
to  noticeably  exhibit  either  acid  or  basic  properties.  The  only  groups 
in  cotton  cellulose  which  may  be  considered  chemically  active  are  the 
hydroxyl  groups.  These  can  be  rendered  inactive  by  acetylation,  and 
it  has  been  shown  ^  that  cotton  so  treated  does  not  exhibit  any  difference 
in  dyeing  properties  from  ordinary  cotton,  and  this  leads  us  to  the 
assumption  that  in  the  case  of  cotton,  the  phenomena  of  dyeing  rest  on  a 
physical  dissociation  of  the  dyestuff  molecule  determined  by  the  fiber; 
that  is  to  say,  the  process  of  dyeing  with  reference  to  cotton  must  be 
attributed  (in  great  measure  at  least)  to  the  action  of  dissociation,  disso- 
lution, and  capillarity;  in  other  words,  to  purely  physical  or  physico- 
chemical  causes;  and  purely  chemical  reactions,  if  they  come  into  play 
at  all,  are  of  secondary  importance. 

The  method  of  combination  between  fiber  and  dyestuff  is  explained 
by  Krafft  ^  as  a  separation  of  colloid  salts  on  or  in  the  fiber.  With  basic 
colors,  the  soaps  and  the  colloid  tannin  are  chiefly  used  for  the  purpose 
of  forming  insoluble  colloid  compounds  with  the  dyes;  with  acid  colors 
metallic  mordants  which  are  themselves  colloids,  like  the  hydrates  of 
iron,  aluminium,  cromium  and  tin,  are  used.  These  conditions  are 
necessary  to  produce  fast  colors  with  dyes  of  molecular  weight  and  of  small 
dyeing  capacity  on  the  cotton  fiber.  With  azo  dyes  of  high  molecular 
weight,  which  dye  cotton  directly,  it  is  probable  that  they  are  all  colloidal 
substances.  Tannin,  which  is  the  most  important  fixing  agent  in  the  dye- 
ing of  cotton,  has  a  high  molecular  weight  and  is  a  colloid.  Both  ferric 
hydrate  and  aluminium  hydrate  are  colloidal. 

1  See  Rosenthal,  Bidl.  Soc.  Chem.,  1911,  pp.  12  and  224. 

-  Suida,  Fdrber-Zcit.,  1905.  ^  Berichte,  1899,  p.  1608. 


ACTION  OF  COLORING  MATTERS  551 

Kuhn  1  finds  there  is  a  greater  deposition  of  coloring  matter  along  the 
lumen  of  the  fiber  according  as  the  dyeing  process  is  more  complete, 
although  even  in  the  best  dyed  fibers  the  largest  proportion  of  dyestuff 
is  deposited  on  the  outer  surface.  De  Mosenthal  has  pointed  out  that 
a  single  fiber  does  not  absorb  coloring  matter  by  capillary  attraction, 
but  the  dyestuff  solution  apparently  rises  between  the  fibers  and  passes 
into  them  through  the  pores  in  the  cell- wall.  Crum  believed  that  the 
coloring  matter  was  deposited  within  the  central  canal  or  lumen;  but 
O'Neill  showed  that  this  was  seldom  the  case,  the  whole  cell-wall  being 
colored  in  a  uniform  manner.  According  to  Georgievics  a  porous  structure 
of  the  cotton  fiber  could  hardly  be  considered  essential  to  its  dyeing,  for 
fibers  not  possessing  any  organic  structure  at  all  (such  as  the  various 
forms  of  artificial  silk)  can  be  dyed  in  practically  the  same  manner  as 
cotton.  Recent  work  by  Haller  has  shown  that  cotton  dyed  with  chrome 
yellow  when  examined  in  cross-section  even  under  a  magnification  of 
1000  diameters,  failed  to  exhibit  any  trace  of  porous  structure.  The  cell- 
walls  were  homogeneously  impregnated  with  the  color  in  a  very  fine  state 
of  division.  Haller  has  shown  also  that  cotton  fibers  still  attached  to 
the  seed-shell  dye  as  satisfactorily  as  ordinary  cotton  fibers.  In  this  case 
both  ends  of  the  fiber  are  closed,  and  the  central  canal  is  not  exposed  to 
the  capillarity  of  color  solutions;  hence  it  is  to  be  concluded  that  the 
central  canal  in  the  cotton  fiber  does  not  play  any  important  part  in  the 
dyeing  process. 

Minajeff  -  by  comparing  the  action  of  dyestuffs  on  artificial  silk  and 
cotton  concludes  with  reference  to  the  latter  that  (a)  the  cuticle  of  the 
bleached  fiber  has  no  influence  on  the  dyeing  process,  (6)  the  lamellar 
structure  of  cotton  plays  no  part  in  differentiating  its  dyeing  action  from 
that  of  artificial  silk,  and  (c)  the  canal  in  the  cotton  fiber  plays  no  important 
role,  mordants  and  color-lobes  being  deposited  within  the  canal  to  only 
a  very  limited  extent.  The  determining  factors  appear  to  be  thickness, 
density,  and  capillarity,  rather  than  microscopic  structure. 

Rona  and  Michaelis  ^  affirm  that  the  apparent  absorptive  power  of 
cotton  for  dyes  is  really  due  to  an  exchange  of  mineral  matter  for  dye, 
and  support  this  view  by  the  fact  that  in  the  absorption  of  Methylene 
Blue  the  chlorine  content  and  the  hydrogen  ion  concentration  of  the  solu- 
tion remain  constant. 

Cotton  yarn  may  be  prepared  so  as  to  "  resist  "  dyeing  with  direct 
cotton  colors,  by  treatment  with  mixed  nitric  and  sulfuric  acids  so  as  to 
produce  a  hexanitrated  cellulose.  Fothergill  ^  has  shown  that  if  cotton 
yarn  be  mordanted  with  tannate  of  tin  it  becomes  practically  resistant 
to  the  direct  cotton  colors,  and  if  woven  in  connection  with  untreated 
yarn  gives  a  "  melange  "  or  two-color  effect. 

1  Die  Baumwolle,  p.  183.  '  Biochem.  Zeitsch.,  1920,  pp.  19-29. 

2  Zeit.  Farb.  Ind.,  1909,  p.  236.  *  Jour.  Soc.  Dyers  &  Col,  1907,  p.  251. 


552 


CHEMICAL  PROPERTIES  OF   COTTON 


18.  Effect  of  Chemical  Processes  on  Cotton  Fabrics. — The  various 
operations  of  boiling-out,  bleaching  and  dyeing,  and  mercerising  exert 
considerable  influence  on  the  weight  and  strength  of  cotton  fabrics. 
E.  Midgley  ^  has  made  some  interesting  tests  on  this  subject,  the  results 
of  which  are  given  in  the  following  tables: 

Effect  of  Processes  on  Weight 


Origi- 
nal 
Weight. 

After  Treatment. 

Treatment. 

2/40's 
Ameri- 
can. 

2/120's 

Sea- 
island. 

1/50's 
Egyp- 
tian. 

2/40's 
Egyp- 
tian. 

2/60's 
Egyp- 
tian. 

1/40's 
Egyp- 
tian. 

Mean. 

Boiling  water .... 

Bleached 

Mercerised 

Aniline  Black .... 
Logwood  Black . . . 

100 
100 
100 
100 
100 

96 

95 

98 

105 

105 

95 

93 

96 

103 

105 

95 

93 

96 

103 

107 

97 

93 

98 

104 

105 

97 

95 

98 

104 

106 

97 

95 

97 

104 

107 

96 

94 

97 

104 

106 

Average  Results  Illustrating  the  Influence  of  Various  Treatments  on  Three 
Types  of  Cotton  Yarns:  2/120's  Sea-island  (Combed);  2/40's  American 
(Carded);  1/50's  Egyptian  (Combed) 


Weight. 


Length. 


Strength. 


Elonga- 
tion. 


1.  Gray 

2.  Bleached— 

(a)  Chlorine 

(b)  Permanganate 

(c)  Peroxide 

Average .  .  .  . 

3.  Dyed  Black— 

(a)  Aniline 

(6)  Sulfur 

Average .... 

4.  Boiled  in  Water — 

(a)  2  hours 

(6)  4  hours 

(c)   6  hours 

Average . . . 


100 


100 


100 


100 


97 
97 
93 


97 
96 
96 


94 
93 

87 


92 

96 

102 


95  = 

110 
104 


96  J 

96 
96 


122 
108 


93 

98 
93 


107 

97 
94 
94 


96 

97 
97 
97 


115 

104 
100 
100 


95 

104 

102 

98 


95 


97 


101^ 


101 


Textile  Manufacturer. 


ACTION   OF   FERMENTS   ON   COTTON 


553 


Pickles  ^  has  made  a  detailed  investigation  of  the  effect  of  various 
treatments  on  cotton  yarn.  The  yarn  employed  for  the  tests  was  2/40's 
and  2/60's  Egyptian  cotton,  and  the  results  are  shown  in  the  accompanying 
tables : 


Process. 


Gray  yarn,  2/40's 

Boiling  water  without  tension . 
Boiling  water  with  tension .... 

Bleaching  powder 

Permanganate  bleach 

Mercerised  with  tension 

Mercerised  without  tension .  .  . 

Developed  black 

Sulfur  black 

Direct  black 

Logwood  black 


Weight 
After 
Treat- 
ment. 


100.0 
97.5 
97.7 
94.4 
93.9 
98.7 

100.4 
99.7 

104.1 
99.1 

105.6 


Length 
After 
Treat- 
ment. 


100 
100 
100 
100 
100 
100 
83 
100 
100 
100 
100 


strength. 


100.0 
101.7 
100.6 

98.2 

91.3 
125.1 
136.9 

96.1 
103.5 

98.1 
107.0 


Elonga- 
tion. 


100.0 

102.9 

100.0 

80.7 

89.8 

75.5 

196.0 

93.1 

90.0 

93.9 

90.0 


Moisture 
Regain, 
Percent. 


8.8 
8.1 
8.0 
8.4 
8.7 
11.1 
13.1 
8.9 
8.8 
8.8 
8.8 


Similar  tests  were  also  made  with  single  yarns  of  American,  Sea-island 
and  Egyptian  cotton  with  about  the  same  relative  results. 

19.  Action  of  Ferments  on  Cotton. — Though  resistant  to  the  action 
of  moths  and  insects  in  general,  cotton  is  liable  to  undergo  fermentation 
as  is  evidenced  by  the  formation  of  mildew  on  cotton  fabrics  stored  in 
damp  places.  Though  this  fermentation  is  often  induced  by  the  presence 
of  more  or  less  starchy  matter  contained  in  the  sizing  materials  used  in 
finishing  the  goods,  yet  pure  cellulose  itself  can  also  be  fermented,  and 
Omeliansky  has  succeeded  in  isolating  the  particular  bacillus  which 
destroys  cellulose. 

According  to  Knecht  ^  human  saliva  has  a  peculiar  and  distinct  effect 
on  cotton.  His  experiments  show  that  a  piece  of  bleached  calico,  saturated 
with  saliva,  will  absorb  considerably  more  dyestuff  on  dyeing  with  sub- 
stantive colors  than  untreated  cotton.  This  is  not  due  to  mucus,  or  to 
any  of  the  salts  contained  in  the  saliva,  but  probably  to  the  enzyme 
ptyalin,  since  the  saliva  loses  the  power  of  producing  the  effect  after  boiling. 
Of  other  enzymes,  diastase  was  also  found  to  have  some  action,  though 
very  slight.  This  action  of  saliva  on  cotton  may  explain  some  faults 
arising  in  dyeing  cotton  pieces. 

Malt  extracts  have  long  been  employed  to  assist  in  the  removal  of 
starch  from  sized  fabrics,  but  attention  has  recently  been  directed  to  the 

1  Report  Bradford  Tcchn.  College.  1910. 

2  Jour.  Soc.  Dyers  &  Col.,  1905,  p.  189. 


554  CHEMICAL  PROPERTIES   OF   COTTON 

application  of  enzymes  as  a  substitute  for  the  alkali  boil  for  the  removal 
of  the  various  impurities  present  in  the  raw  fiber.  It  has  shown  nearly 
thirty  years  ago  by  Herbert  ^  that  bacteria  which  destroy  cellulose  do  not 
attack  the  cellulose  molecule  proper  until  adherent  pectins,  gums,  and 
tannins  have  been  decomposed.  Recently,  Levine  -  has  examined  the 
action  of  B.  amylolyticus,  B.  fimi,  B.  bibulus,  B.  carotovorous,  and  B.  suh- 
tilis  on  unbleached  cotton  in  a  nutrient  medium  containing  dipotassium 
hydrogen  phosphate,  magnesium  sulfate,  sodium  chloride,  ammonium 
sulfate  and  lime.  He  found  that  the  nitrogenous  substances  and  constitu- 
ents which  are  soluble  in  ether  are  efficiently  removed,  but  that  the  impur- 
ities soluble  in  alcohol  are  only  attacked  by  B.  carotovorous  and  B.  subtilis. 
In  the  case  of  B.  hibulus  and  B.  fimi,  the  cloth  became  weaker,  which  may 
have  been  due  to  the  action  of  air  on  parts  incompletely  submerged.  On 
the  large  scale,  the  material  was  incubated  with  the  bacterial  culture  for 
periods  ranging  from  twenty-four  to  seventy-two  hours,  with  encouraging 
results.  Rohm  ^  has  patented  the  substitution  of  the  alkali  boil  by  a 
steep  in  a  0.1  percent  solution  of  pancreatin  at  68°  to  104°  F.  for  some 
hours,  other  enzymes  such  as  papayotin  ferments  serving  the  same  end. 
20.  Action  of  Mildew  on  Cotton. — Mildew  does  not  appear  as  often 
on  white  and  colored  as  on  gray  (unbleached)  cloth,  which,  being  sized, 
is  much  more  liable  to  this  defect.  The  essential  conditions  for  the  pro- 
duction of  mildew  appear  to  be  (1)  dampness,  (2)  lack  of  fresh  air,  (3)  the 
presence  of  certain  bodies  (such  as  flour,  etc.)  suitable  as  foods  for  the 
fungi.     The  more  common  varieties  of  mildew  are: 

(1)  Green  mildew,  a  common  form  generally  due  to  Penicillium  glaucum  and 
Aspergillus  glaucus,  which  are  closely  allied,  but  which  are  distinguishable  from  the 
way  in  which  the  spores  are  attached.  In  the  former  the  spores  are  on  branches, 
while  in  the  latter  they  are  attached  to  the  head;  they  grow  rapidly  and  generally 
form  rather  large  patches. 

(2)  Brown  mildew  is  frequently  found  on  cloth,  and  is  due  to  various  species  of 
fungi,  of  which  Puccinin  graminis  is  perhaps  the  most  common.  This  and  the  brick- 
red  mildew  noticed  below  are  frequently  mistaken  for  iron  stains,  the  color  of  which 
they  closely  resemble.  They  are  easily  distinguished  by  the  manner  in  which  they 
occur  in  small  spots,  often  of  a  rmg  shape,  and  they  do  not  give  the  Prussian-blue 
test. 

(3)  Brick-red  mildew  is  not  very  frequent  and  the  fungus  which  causes  it  has  not 
been  definitely  recognised;  it  grows  rapidly  at  first,  but  has  no  great  vitaUty  and 
after  a  time  the  development  stops. 

(4)  Yellow  mildew,  a  common  variety  occurring  in  large  irregular  patches  and 
spots.  Not  requiring  much  air  for  its  development,  it  extends  much  more  into  the 
folds  of  the  cloth  than  do  most  of  the  other  kinds.  It  is  a  yellow  variety  of  the 
Aspergillus  glaucus  {Eurolium)  and  may  also  be  Oidium  aurantiacum. 

^  Ann.  Agronom.,  1892,  p.  536. 
^Jour.  Ind.  Eng.  Chem.,  1916,  p.  298. 
3  Bril.  Pal.  100,224  of  1916. 


ACTION  OF  MILDEW  ON  COTTON  555 

(5)  Black  mildew,  due  often  to  fungi  belonging  to  the  genus  Tilletia,  is  occasionally 
found;  it  is  very  rapid  in  growth. 

(6)  Purple  mildew  is  rare. 

(7)  Bright  pink  mildew  is  also  rare. 

With  the  help  of  the  viscose  treatment  it  is  possible  to  show  that 
changes  occur  in  the  structure  of  the  cotton  fibers  when  attacked  by 
bacteria.  A  method,  based  on  this  observation,  is  described  for  the 
quantitative  determination  of  the  bacterial  deterioration  of  cotton. 
Applied  to  cottons  of  various  origins,  this  "  swelling  test  "  shows  that  a 
difference  exists  in  the  susceptibility  to  attack  by  bacteria,  and  that 
Indian  cottons  deteriorate  quicker  than  American  samples.     Samples  of 


Fig.  213.— Cotton  Fibers  Infected  with  Mildew. 

cotton  grown  in  India  from  American  seed  were  found  to  be  as  resistant  to 
attack  as  American  cottons. 

From  investigations  by  Denham  ^  on  the  destruction  of  cotton  fibers 
by  micro-organisms,  it  is  apparent  that  serious  damage  may  exist  in  the 
cotton  before  any  indication  of  its  presence  can  be  detected  by  the  usual 
tests,  and  that  one  or  two  points  of  infection  may  seriously  interfere  with 
the  spinning  qualities  of  the  fiber.  It  therefore  becomes  of  importance  to 
guard  against  the  possible  development  of  micro-organisms  in  all  stages  of 
manufacture,  particularly  in  those  processes,  such  as  conditioning,  which 
involve  the  addition  of  moisture  to  cotton.  Photomicrographs  of  infected 
cotton  fibers  are  shown  in  Figs.  213  and  214. 

Goods  to  be  paraffined  should  be  dyed  by  a  method  which  incorporates 
in  the  goods  mildew-resisting  qualities  before  the  waxing  occurs,  and 
^Jour.  Text.  Inst.,  1922,  p.  240. 


556 


CHEMICAL   PROPERTIES   OF   COTTON 


this  is  most  readily  done  by  dyeing  with  cutch  instead  of  with  coal-tar 
dye  products.  Mineral  dyed  khaki  has  considerable  antiseptic  qualities 
due  to  the  oxide  producing  the  color,  and  mineral  dyed  khaki  paraffined 
is  a  much  better  fabric  than  goods  dyed  with  sulfur  colors,  or  direct  colors, 
and  then  waxed.  White  paraffined  duck  goods  without  an  antiseptic 
preliminary  treatment  have  little  resistance  to  mildew,  but  are  very  cheap, 
and  for  some  purposes  very  satisfactory  fabrics. 

Cotton  fabrics,  especially  canvas,  may  also  be  made  mildew-proof  by 
treatment  with  cuprammonium  solution.  This  reagent  partially  dissolves 
the  cellulose  and  forms  a  film  or  varnish  over  the  fiber.  The  product 
has  been  manufactured  to  some  extent,  under  the  name  of  Willesden 
canvas,  for  use  as  tarpaulin  and  tent  material.     The  process,  however,  is 


Fig.  214.— Fibers  of  Cotton  Infected  with  Mildew. 


rather  costly.  These  cuprammonium  fabrics  are  by  far  the  most  mildew- 
proof  of  all  commercially  produced  finishes.  Their  color  is  not  entirely 
permanent  to  light,  the  green  color  due  to  the  copper  fading  out  as  the 
compound  becomes  reduced  after  severe  exposure;  but  the  copper  is 
nevertheless  there  in  a  leuco  or  white  state  and  the  change  in  color  does  not 
seem  to  diminish  the  mildew-proof  quality  of  the  goods.  The  green  color 
may  be  modified  to  some  extent,  either  by  chemical  fumes  which  change 
the  copper  superficially  to  sulfide  or  oxide,  by  dyeing  the  fabric  before  the 
treatment,  or  by  after-treatment  with  colored  varnishes. 

Some  zinc  solutions  have  a  similar  property  but  do  not  make  as  good 
coatings  and  lack  some  of  the  desirable  features  of  the  copper  solutions. 
The  latter  can  be  modified  either  to  leave  the  goods  soft  yet  saturated, 
or  to  glaze  the  yarns  and  fibers,  and  the  latter  result  is  a  most  beautiful, 
shining,  silky,  pale  green  or  dark  green  fabric. 


TESTING  CANVAS  FOR  MILDEW  RESISTANCE  557 

21.  Testing  Canvas  for  Mildew  Resistance. — The  standard  method  is 
to  collect  a  variety  of  mildew  growths  by  exposing  bread  crust  or  similar 
material  to  the  air  for  a  few  hours,  and  then  confining  it  with  a  little 
water  in  a  closed  container,  kept  in  a  warm,  dark  place.  Mould  can 
readily  be  obtained  from  diastafor,  and  other  substances  common  in  the 
mill,  by  the  same  treatment.  The  tester  should  endeavor  to  secure  a 
considerable  variety  of  mildew.  It  will  be  found  convenient  to  use  the 
lower  half  of  a  desiccator  to  hold  the  growths,  and  suspend  samples  within 
from  wires.  A  moist  condition  should  be  maintained  inside,  and  the 
mildew  jar  kept  in  a  cupboard  away  from  the  light.  Test  samples  should 
not  develop  mildew  growths  in  five  days  of  this  exposure. 

The  development  and  action  of  mildew  on  cotton  fabrics  has  been 
thoroughly  studied  by  Levine  and  Veitch,^  and  they  have  also  devised 
methods  to  determine  the  mildew  resistance  of  such  fabrics,  particularly 
for  use  in  the  army  and  navy.  Mildewing  is  due  to  the  development  of 
various  mould  growths  on  and  in  the  fabric.  The  number  of  species 
responsible  for  the  deterioration  is  large,  but  chief  among  them  are  the 
species  of  Alternaria,  of  Cladosporium,  and  some  Mucors.  The  simul- 
taneous occurrence  of  different  kinds  of  moulds  seem  to  play  an  important 
part,  and  the  production  of  pink  and  yellowish  discolorations  is  probably 
due,  at  least  in  some  cases,  to  the  growth  of  both  a  Mucor  and  a  mould, 
producing  a  substance  having  a  pink  appearance  in  alkaline  or  neutral 
reaction  and  a  yellow  one  in  an  acid  reaction. 

Gueguen  ^  is  of  the  opinion  that  the  spores  causing  the  mildewing 
of  fabrics  are  usually  introduced  into  the  fibers  by  the  dead  part  of  the 
parent  cotton  plant,  where  they  have  been  either  in  a  dormant  or  germinat- 
ing state,  and  concludes  that  mildew  is  hardly  ever  due  to  contamination  of 
the  fabric  after  weaving. 

The  presence  in  the  air  of  spores  of  cellulose-destroying  fungi  has  been 
demonstrated  by  McBeth  and  Scales,  who  have  isolated  from  plates 
exposed  to  air  contamination  over  a  dozen  cellulose-destroying  organisms, 
among  which  Cladosporium  herbarum  has  been  identified.  Davis,  Dreyfus, 
and  Holland  have  shown  that  astonishingly  large  numbers  of  mould  spores 
rain  into  the  mill  vats  containing  sizing  materials  used  on  the  component 
threads,  thereby  becoming  introduced  into  the  woven  fabric. 

Tests  for  mildew  resistance  of  fabrics  have  been  in  use  heretofore. 
One,  occasionally  followed,  is,  briefly,  to  bury  a  sample  of  the  cloth  under 
ground  at  a  depth  of  12  to  15  ins.  for  a  period  extending  over  one  month. 
The  ground  is  kept  moist  by  occasional  watering.  The  condition  of  the 
fabric  at  the  end  of  the  test  period  is  considered  to  indicate  the  degree 
of  mildew  resistance. 

1  U.  S.  Bureau  of  Chemistry. 

^  Comptes  rendus,  vol.  159,  p.  781 . 


558  CHEMICAL  PROPERTIES  OF  COTTON 

This  method  may  give  valuable  information  regarding  the  resistance 
of  fabrics  to  bacterial  action,  but  its  value  for  determining  mildew  resistance 
is  questionable.  Canvas  buried  under  ground  would  be  subject  to  bacterial 
rather  than  to  fungus  attack.  That  this  is  so,  is  indicated  by  the  fact  tliat 
cotton  duck  coated  with  a  thin  layer  of  paraffin  remained  practically  unat- 
tacked  when  buried  under  ground  for  nearly  a  month,  whereas  mildew 
developed  in  less  than  a  month  when  inoculated  in  the  laboratory. 

Another  method  is  to  roll  together  several  samples  of  the  cloth  to  be 
tested  with  layers  of  fresh  horse  manure  and  of  sawdust  and  keep  for 
about  a  month  in  a  moist  condition.  At  the  end  of  the  period  the  condition 
of  the  cloth  is  observed,  and  if  no  deterioration  is  evident,  the  samples  are 
again  rolled  up  and  left  for  another  month  or  two. 

Levine  and  Veitch  recommend  the  following  procedure:  Cut  six  disks 
about  3|  ins.  in  diameter  from  the  sample  to  be  tested  and  place  in  running 
water  at  room  temperature  for  at  least  two  days.  In  the  absence  of 
running  water  place  the  disks  in  a  beaker  of  water  and  change  the  water 
several  times  during  the  day.  This  soaking  and  washing  is  for  the  purpose 
of  removing  from  the  fabric  as  much  of  the  water-soluble,  germicidal,  and 
fungicidal  substances  as  possible  and  also  the  fermentable  material.  If 
these  are  left  in  the  fabric,  they  may  suspend  or  hasten  the  development 
of  the  mildew  spores,  making  it  appear  that  the  fabric  is  highly  mildew- 
resistant  or  highly  susceptible,  whereas  in  practice  the  substances  may  be 
almost  completely  washed  out  by  the  first  rain,  and  the  resistance  of  the 
fabric  become  markedly  different. 

At  the  end  of  the  period  of  soaking,  place  the  disks  between  clean 
blotting  papers  or  towels  and  remove  excess  of  water  by  pressure.  Place 
the  disks  in  six  bacteriological  Petri  plates  containing  10  to  15  cc.  of  plain 
agar  jelly  free  from  nutrient  matter,  being  careful  that  the  plates  do  not 
become  airtight.  The  plates  with  the  disks  are  incubated  in  a  closed 
chamber  at  a  temperature  of  20°  to  25°  C.  for  seven  to  ten  days.  If  they 
show  a  heavy  and  well-developed  growth,  the  test  is  discontinued.  If, 
however,  the  growth  of  mould  is  entirely  absent  or  is  merely  starting,  the 
disks  are  inoculated  with  stock  cultures  of  Alternaria,  Cladosporium,  and 
a  pink  Mucor,  and  further  incubated  for  three  to  four  weeks.  The  first 
period  of  incubation  is  designated  for  convenience  as  the  "  pre-inoculation 
period." 


CHAPTER  XVIII 

CHEMICAL   TREATMENT   OF   FABRICS   FOR   WATERPROOFING 
AND  FLAME-PROOFING 

1.  Waterproofing  of  Fabrics.— A  large  variety  of  fabrics  are  now 
finished  so  as  to  be  more  or  less  waterproof,  or,  more  strictly  speaking, 
water-resistant.  Fabrics  of  cotton,  wool,  silk,  or  of  mixed  fibers  may  be 
given  this  property. 

Waterproof  fabrics  may  be  divided  into  two  distinct  classes:  (1)  those 
comprising  various  textures  and  cloths  which  have  been  treated  chemically 
to  make  them  water-repellent,  thus  preventing  the  passage  of  the  moisture 
except  under  pressure.  In  this  class  the  surface  tension  of  the  liquid 
plays  an  important  pait.  (2)  The  second  class  consists  of  fabrics  which 
have  been  coated  or  encirely  covered  with  some  waterproofing  substance, 
and  are  impenetrable  to  both  air  and  moisture.^  Oilskins  and  mackin- 
toshes are  examples  of  this  class.  The  first  thing  to  be  recognised  in  the 
consideration  of  waterproofed  fabrics  is  that  a  closely  constructed  material 
is  more  likely  to  resist  the  percolation  of  the  water  than  a  loosely  constructed 
fabric;  hence  the  closer  the  weave  the  easier  it  will  be  to  waterproof  the 
fabric.  In  physical  structure  each  wool  fiber  is  a  capillary  tube,  and  the 
capillary  action  of  these  tubes  explains  the  affinity  of  wool  for  moisture. 
If  a  wool  fiber  be  placed  under  the  microscope  and  brought  in  contact  with 
a  drop  of  water  it  will  be  found  that  the  water  is  sucked  up  by  the  fiber 
with  great  avidity.  To  render  the  fiber  waterproof,  then,  it  will  be  neces- 
sary to  fill  or  coat  these  capillary  tubes  with  some  substance  insoluble  in 
water.  Subjecting  the  fiber  to  the  action  of  superheated  steam  seems  also 
to  close  up  these  capillary  tubes,  possibly  by  fusion  of  the  cells.  If  the 
threads  of  yarn  are  also  surrounded  with  a  water-repellent  substance  it  is 
possible  to  waterproof  even  loosely  woven  fabrics.  If  water  is  placed  on 
fabrics  thus  treated  it  assumes  the  form  of  small  spherical  drops  which 

*  The  very  best  kind  of  waterproofing  agent  is  one  that  will  allow  the  comparatively 
free  passage  of  the  air  and  permit  of  the  moistening  of  the  outer  surfaces  of  the  cloth, 
but  which  opposes  the  passage  of  the  water  to  the  other  side,  and  there  are  a  number 
of  colloidal  precipitates  which  will  fulfil  this  requirement — colloidal  alumina  and  tin, 
gelatine,  glue  and  casein,  rendered  insoluble  by  chromic  acid,  alum  or  paraffin. 
Colloidal  alumina  may  be  prepared  from  the  diacetate  of  alumina;  this  in  the  presence 
of  much  water  furnishes  a  hydrosol  of  alumina  which  is  precipitated  in  a  gelatinous 
form 

559 


560     CHEMICAL  TREATMENT  OF   FABRICS   FOR   WATERPROOFING 

may  be  easily  shaken  off  and  leave  no  trace  of  wetting.  If,  however,  the 
water  is  subjected  to  pressure  on  the  cloth,  these  spherical  drops  may  be 
forced  through  the  interstices  of  the  fabric  without  really  wetting  the 
fiber  at  all. 

W.  B.  Nanson  (Cotton)  states  that  in  the  waterproofing  of  cotton 
goods  most  of  the  chemical  processes  employed  allow  the  goods  to  retain 
their  original  color,  softness  and  suppleness,  except  in  a  few  cases;  if  tan- 
nin, for  instance,  is  used,  the  color  of  the  fabric  becomes  somewhat  darker 
but  the  difference  is  hardly  noticeable  in  most  cases.  If  either  a  bleached 
or  unbleached  fabric  is  waterproofed  with  aluminium  acetate,  its  appear- 
ance and  feel  remain  the  same.  The  following  substances  are  used  more 
particularly  for  waterproofing  cotton  goods:  Sulfate  and  acetate  of 
alumina,  acetate  of  lead,  the  sulfates  of  copper,  zinc  and  iron,  ammonium 
cuprate,  paraffin,  ceresin,  wax,  soap,  casein,  etc. 

Most  of  the  processes  used  for  waterproofing  cotton  fabrics  involve, 
to  a  greater  or  less  degree,  the  application  of  the  colloid  theory,  by  the 
precipitation  upon  and  in  the  fibers  as  a  hydrated  metallic  oxide,  or  a 
tannin,  in  combination  with  some  other  colloid  substance,  as  albumen, 
glue,  casein,  the  fatty  acids  (soaps). 

2.  Use  of  Aluminium  Acetate. — Waterproofing  with  aluminium  ace- 
tate is  perhaps  the  most  common  process  and  is  in  general  use  for  water- 
proofing covert  coatings  and  similar  fabrics.  The  older  method  was  to 
mix  solutions  of  alum  and  sugar  of  lead  (lead  acetate)  and  to  apply  the 
solution  to  the  piece  by  steeping  or  padding.  The  pieces  after  scouring 
and  washing  were  hydroextracted,  and  without  drying,  the  solutions 
were  applied.  The  alum  or  double  sulfate  of  potassium  and  aluminium 
was  then  replaced  by  aluminium  sulfate,  and  this  is  in  common  use  at 
the  present  time.  A  safer  plan  is  to  use  a  solution  of  aluminium  acetate 
made  by  the  double  decomposition  of  aluminium  sulfate  and  calcium 
acetate : 

One  hundred  pounds  calcium  acetate  and  700  lbs.  sulfate  of  alumina 
are  separately  dissolved  in  water  and  brought  together  in  a  mixing  vessel. 
The  precipitate  of  calcium  sulfate  is  allowed  to  settle,  and  the  solution 
filtered  through  cloths  or  a  filter  press.  As  gray  a  shade  of  calcium  ace- 
tate as  possible  should  be  chosen,  as  brown  or  black  forms  produce  a  tarry 
or  discolored  acetate  which  is  unsuitable  for  proofing  light-colored  goods. 
There  are  three  methods  of  application  of  aluminium  acetate: 

(I)  Treatment  with  aluminium  acetate  in  the  padding  machine  for  twenty  minutes 
to  half  an  hour,  followed  by  tentering  or  drying  by  passing  over  hot  cyhnders.  The 
acetic  acid  is  evaporated  off  and  the  aluminium  left  on  the  fabric  in  the  form  of  an 
insoluble  basic  acetate  which  is  repellent  to  moisture. 

(II)  The  second  method  of  application  is  to  pad  for  twenty  minutes  in  aluminium 
acetate  of  from  3°-5°  Be.  and  then  to  after-treat  another  twenty  minutes  with  a 


USE  OF   GELATINE  AND   CASEIN  561 

solution  of  sodium  carbonate,  potassium  carbonate,  or  ammonia.  This  precipitates 
the  aluminium  on  the  fabric  in  the  form  of  the  hydroxide  which  dries  to  the  oxide  on 
tentering. 

These  two  methods  produce  a  moderately  waterproof  article,  and  on  account  of 
their  cheapness  are  generally  used  for  low  goods  and  unions.  After  wearing  some 
time  the  alumina  tends  to  appear  on  the  surface  of  the  cloth  in  the  form  of  a  white 
powder  which  may  be  brushed  off,  and  the  waterproof  value  is  gradually  lost. 

(Ill)  The  third  method,  which  tends  to  remedy  these  faults,  is  to  impregnate  with 
the  acetate  as  before,  and  then  after-treat  with  soap  solution.  The  aluminium  is  thus 
precipitated  in  the  form  of  an  insoluble  aluminium  soap  which  tends  to  cling  better  to 
the  fiber  and  is  more  water  repellent  than  either  the  basic  acetate  or  oxide.  If  excess 
of  soap  solution  is  used  a  "sticky"  feel  is  imparted  to  the  fabric.  This  may  be  remedied 
by  passing  the  material  through  alum  solution  of  1°-H°  Be. 

3.  Use  of  Fats  and  Waxes. — Soap  solution  possesses  the  property  of 
emulsifying  india-rubber  solution,  boiled  oil,  water  glass,  dextrin  and 
other  gums,  and  the  various  waxes,  such  as  paraffin,  carnaiiba,  Japan  and 
beeswax.  These  bodies  are  valuable  in  making  the  cloth  water-repellent 
and  when  used  as  adjuncts  to  the  soap  bath,  they  are  thrown  down  where 
the  alumina-impregnated  fabric  is  passed  through  the  solution.  They 
adhere  very  tenaciously  to  the  cloth  and  greatly  enhance  its  waterproof 
value.  Fabrics  treated  in  this  way  will  stand  a  pressure  of  about  12  ins., 
while  with  a  simple  soap  bath  the  maximum  pressure  is  about  2  ins. 

The  following  is  a  typical  example  of  a  soap  bath  made  up  with  Japan 
or  carnaiiba  wax  and  a  10  percent  solution  of  para  rubber  in  oil  of  camphor 
or  turpentine.  The  following  quantities  are  required  per  pint  of  liquid: 
Soap,  1  oz.;  wax,  |  oz.;  rubber  solution,  20  grains.  The  wax  is  melted 
and  the  rubber  solution  mixed  in,  and  the  mixture  added  to  the  boiling 
soap  solution. 

Chloro-hydrocarbon  solutions  of  sulfonated  oils  are  excellent  for  incor- 
porating rubber  and  waxes  into  the  soap  solution  though  rather  expensive. 

4.  Use  of  Gelatine  and  Casein. — A  satisfactory  waterproof  cloth  is 
obtained  by  padding  with  gelatine  or  casein  solution  and  treating  with  a 
second  solution  to  render  the  gelatine  insoluble.^  Substances  possessing 
this  property  are  formaldehyde,  acetaldehyde,  tannin  and  bichromate 
of  potash.  If  aldehydes  are  used  the  gelatine  may  be  replaced  by  any  of 
the  vegetable  and  marine  gums,  the  majority  of  which  form  insoluble 
aldehyde  compounds.  Bichromate  of  potash  and  tannin  should  only  be 
used  with  dark  colored  heavy  goods,  as  they  produce  a  dark  brown  color, 

^  Three  and  one-half  parts  of  chromic  oxide  render  100  parts  of  gelatine  insoluble, 
and  it  is  the  more  stable  the  less  it  contains  of  free  acid.  It  is  necessary  to  bear  in 
mind  that  chromic  acid  and  its  salts  render  gelatine  insoluble  in  the  presence  of  light, 
also  that  chromic  aldehyde  acts  upon  gelatine  (or  casein)  either  in  the  gaseous  state 
or  in  solution.  It  must  be  remembered,  however,  that  all  waterproofing  processes 
involving  glue,  gelatine  or  casein  will  render  the  goods  stiff — to  avoid  this  castor  oil 
or  some  neutral  soap  must  be  added  to  the  mixture  to  keep  it  soft  and  pliable. 


562     CHEMICAL   TREATMENT   OF   FABRICS   FOR    WATERPROOFING 

and  also  cause  light  weights  to  stiffen.  A  stiff  feel  is  generally  char- 
acteristic of  gelatine  proofed  goods,  and  it  has  to  be  remedied  by  suitable 
finishing.  Acetaldehyde  is  preferable  to  formaldehyde  in  being  less  volatile 
and  easier  to  manipulate,  and  also  being  less  irritating  to  the  noses  and 
throats  of  the  workpeople.  Thick  sacking  and  wagon  cloths  are  proofed 
by  repeated  treatment  with  gelatine  and  tannin  until  the  interstices  have 
been  filled  up  and  the  texture  almost  hidden.  Alum  solution,  following  up 
treatment  with  gelatine  will  fix  the  gelatine  and  give  a  moderately  water- 
proofed cloth.  In  another  process  the  fabrics  are  thoroughly  soaked  in  a 
mixture  of  isinglass,  alum  and  white  soap.  They  are  then  passed  through 
a  solution  of  sugar  of  lead  and  dried.  Glycerol  is  sometimes  added  to  the 
gelatine  solution  to  prevent  a  "  stiff  "  feel. 

A  process  given  by  Nanson  is  as  follows:  Thoroughly  soak  30  lbs.  (or  any  multiple 
of  it)  of  casein  in  water  overnight;  the  next  morning  add  sufficient  ammonia  to  the 
mixture  to  make  it  soluble;  then  add  15  lbs.  of  pure  tallow  soap  in  solution  bringing 
the  whole  quantity  of  the  mixture  up  to  50  gallons;  heat  this  up  but  do  not  boil  it. 
Pad  the  goods  with  this  mixture  on  a  back  filling  machine,  spreading  the  casein  solution 
on  one  side  only  and  from  this  run  the  goods  directly  and  continuously  through  an 
aging  machine  charged  with  formalin  in  vapor,  regulating  the  speed  so  that  it  wUl 
take  about  ten  minutes  to  run  a  given  point  through  the  machine.  Return  the  goods 
and  repeat  the  process,  spreading  the  casein  this  time,  however,  on  the  reverse  side. 
After  this  second  padding  and  aging  take  the  goods  and  run  them  through  a  cold 
solution  of  acetate  of  alumina  at  7°  Tw.  and  wash  and  dry  at  a  cool  temperature 
preferably  in  the  open,  or  drying  room. 

Lowry's  process  of  waterproofing  is  stated  by  Nanson  to  be  one  of  the  best;  he 
steeps  the  fabric  for  some  hours  in  a  boiling  mixture  of  soap,  glue  and  water  and 
exposes  it  to  the  air  to  partially  dry.  It  is  then  digested  for  ten  hours  in  a  strong 
solution  of  alum  and  common  salt,  then  washed  well  and  dried  at  a  low  temperature 
about  80°  F.  The  efficacy  of  this  process  depends  largely  upon  the  length  of  time  used 
and  the  low  temperature  of  the  drying  processes,  and  it  is  not  very  practical.  It  may 
be  further  said  that  additional  repellency,  as  produced  by  the  precipitation  of  fatty  or 
resinous  soaps  of  the  various  metallic  oxides,  is  of  a  temporary  character  only  and 
will  not  long  remain  after  much  wear  and  tear  and  exjiosure  to  the  oxidising  influence 
of  the  weather. 

There  are  various  processes  by  which  the  goods  are  run  through  mixtures  of  gelatine, 
glue,  or  casein  and  tallow  soap  or  castor  oil  and  alum  boiled  together  and  then  heavily 
squeezed  and  dried  to  about  40°  C.  One  of  the  simplest  of  these  is  as  follows:  Dissolve 
36  lbs.  of  sulfate  of  alumina  in  25  gallons  of  water.  Add  to  this  solution  61 5  lbs.  of 
acetate  of  Hme  dissolved  in  25  gallons  of  water.  Allow  this  to  settle  and  decant  the 
clear  liquor;  to  this  clear  liquor  add  1^  lbs.  of  tannic  acid.  Pad  the  goods  in  this 
and  dry  up,  then  soap  in  tallow  soap  and  dry  up. 

The  caseinate  of  lime  method  is  said  to  insure  the  fabric's  retaining 
its  softness  and  perviousness  to  the  air  and  to  enable  it  to  be  washed 
with  soap,  benzine,  etc.,  without  losing  its  waterproofing  qualities.  The 
process  is  conducted  as  follows:  Casein  is  mixed  with  about  five  times 
its  weight  of  water,  and  the  whole  is  well  stirred  to  a  creamy  liquid. 
This  is  gradually  mixed  with  a  weight  of  slaked  lime  equal  to  about 


USE  OF  PARAFFIN  563 

one-fortieth  of  that  of  the  casein.  At  the  same  time  half  the  weight  of  the 
casein  in  soap  is  dissolved  in  twelve  times  its  weight  of  water,  and  the  soap 
solution  is  mixed  with  the  other.  The  fabric  is  impregnated  with  the  mix- 
ture until  its  weight  is  doubled.  The  fabric  is  next  dipped  in  a  solution 
of  aluminium  acetate  at  7°  Tw.  (cold);  this  makes  the  caseinate  of  hme 
insoluble  and  forms  an  aluminium  soap.  The  fabric  should  then  be 
soaped,  washed  and  dried. 

5.  Waterproofing  Canvas. — The  chief  character  of  fabrics  among  cotton 
goods  that  is  required  to  be  waterproofed  in  canvas,  which  is  so  extensively 
employed  for  tent  material,  tarpaulins,  wagon  covers,  sails,  and  many 
other  uses  where  exposure  to  weather  demands  not  only  real  waterproofing 
but  also  rot-  and  mildew-proofing.  According  to  E.  R.  Clark  (Textile 
World),  nearly  every  experimenter  in  this  field  seems  to  have  different 
ideas  as  to  the  best  method  of  waterproofing  this  kind  of  canvas.  As 
yet,  practice  has  not  become  uniform,  and  nearly  every  firm  has  more  or 
less  different  processes  in  use.  Clark  has  classified  the  various  samples 
which  he  has  examined  as  follows : 

1.  The  aluminium-soap  processes. 

2.  The  asphaltum,  paraffin,  pitch,  etc.,  methods. 

3.  Processes  involving  the  use  of  two  layers  of  fabric. 

4.  Cuprammonium  and  other  processes  based  on  dissolved  cellulose. 

5.  The  drying  oil  methods. 

6.  Use  of  Metallic  Soaps. — Several  metals  have  been  suggested  for  use 
in  connection  with  soap  to  make  waterproofed  canvas,  and  also  several 
kinds  of  soap.  On  the  metallic  side  the  aluminium  compounds  seem  to 
have  established  themselves  as  the  best.  For  the  purpose  basic  aluminiimi 
acetate  is  the  most  frequently  used  salt.  The  use  of  a  hard  soap  is  desir- 
able. Aluminium  soaps  made  from  aluminium  acetate  and  saponified 
linseed  oil  form  an  especially  durable  impregnation.  Practice  in  applying 
the  aluminium  soaps  differs  considerably.  Some  manufacturers  soap  first; 
others  soap  afterward.  Widely  varying  concentrations  have  been  recom- 
mended for  the  solutions,  and  there  are  several  ideas  which  have  been 
worked  out  as  to  the  best  method  of  drying.  While  there  is  no  reason  to 
state  that  the  aluminium-soap  process  cannot  be  made  to  give  a  satisfactory 
canvas,  the  great  majority  of  experiments  along  this  line  have  been  unsatis- 
factory. The  fabrics  prepared  have  shown  a  good  water-repellent  surface, 
but,  on  the  other  hand,  have  been  found  to  permit  the  passage  of  water 
under  severe  conditions  of  service.  The  process  has  been  shown  to  have 
value  for  clothing  materials,  but  for  actually  waterproofed  canvas  for 
field  service  cannot  as  yet  compete  with  the  more  recently  developed 
methods. 

7.  Use  of  Paraffin. — All  things  considered,  the  best  fabrics  for  this 
purpose  have  been  those  the  waterproofing  of  which  was  accomplished 


564     CHEMICAL  TREATMENT  OF   FABRICS   FOR  WATERPROOFING 

by  the  use  of  a  waxy  material  having  suitable  properties  as  regards  melting 
and  hardening  points,  and  permanence  under  the  conditions  of  use. 
Asphaltum  is  a  very  good  material.  It  can  be  applied  melted,  which  is  a 
great  advantage  over  those  materials  which  must  be  dissolved.  Paraffin 
is  widely  used.  The  two  most  marked  disadvantages  of  paraffin  are  its 
tendency  to  become  brittle  and  its  tendency  to  favor  mildew  growths. 
A  paraffin  of  low  melting-point  should  be  used. 

Rosin  is  frequently  and  disadvantageously  incorporated  in  water- 
proofing compounds.  It  is  not  sufficiently  stable  for  this  use,  decomposing 
readily  in  light.  The  decomposition  of  rosin  is  familiar  in  the  browning 
of  rosin-sized  paper.  Further,  it  does  not  seem  to  yield  a  water-repellent 
surface.  Rosin  is  usually  mixed  with  petroleum  to  give  the  desired  con- 
sistency. Even  wool  grease  has  been  used,  although  its  properties  seem 
altogether  unsuitable  for  the  purpose.  Obviously  the  waxy  matter  used 
should  be  one  which  resists  emulsification.  Rubber  mixed  into  melted 
paraffin  makes  an  impregnation  mixture  of  some  value,  resembling  chem- 
ists' stop-cock  grease.  A  large  amount  of  ingenuity  has  been  expended 
in  producing  suitable  mixtures,  and  many  of  them  are  quite  satisfactory. 

Paraffin  duck  is  the  simplest  of  all  waterproofed  fabrics,  and  the  one 
used  in  the  greatest  volume.  A  fine,  firm  well-woven  piece  of  duck,  well 
dyed  and  not  too  heavily  paraffined,  makes  a  very  satisfactory  fabric  for 
many  purposes,  and  has  the  merit  of  being  lower  in  cost  than  anything 
else  that  could  be  described  as  first  class.  It  has  three  marked  defects, 
however.  First,  in  cold  weather  it  becomes  exceedingly  stiff,  owing  to  the 
nature  of  the  paraffin  filling,  in  heavily  filled  goods  to  the  point  of  actually 
cracking  the  cloth  when  it  is  bent,  making  these  articles  nearly  unman- 
ageable in  winter  weather.  Second,  in  hot  climates  or  in  summer  heat,  the 
paraffin  softens  to  an  extent  that  permits  it  to  creep  or  crawl  along  the 
threads  of  the  fabric,  as  it  has  very  strong  capillary  qualities.  This  results 
in  leaks  appearing  in  waterproofed  articles,  sometimes  causing  considerable 
damage.  The  third  point  is  that  paraffin  does  not  protect  the  cotton  itself 
against  mildew.  Sometimes  it  is  believed  that  it  actually  injures  the 
cotton,  but  this  is  not  true  unless  it  does  so  by  breaking  it  on  account  of 
the  stiffness  in  cold  weather.  Paraffin  itself  has  no  chemical  action  what- 
ever on  cotton,  but  it  does  permit  mildew  to  grow  inside  cotton  fabrics 
that  are  covered  with  paraffin  on  the  surface,  as  it  does  not  resist  in  any 
degree  the  growth  of  mildew.  It  is  possible  to  so  manipulate  paraffin 
as  to  grow  mildew  freely  throughout  it  when  in  flakes  or  powdered  form. 

The  necessity  for  mildew  prevention  must  be  always  considered. 
Rosin,  in  spite  of  the  often-repeated  statements  in  the  literature  to  the  con- 
trary, does  not  prevent  the  growth  of  mildew.  The  canvases  prepared 
from  waxes,  etc.,  are  apt  to  be  greasy,  and  these  substances  have  the 
further  objection  of  adding  a  great  deal  to  the  weight  of  the  fabric.     Such 


THE   CUPRAMMONIUM   PROCESS  565 

processes,  as  has  been  stated,  lend  themselves  especially  easily  to  the 
process  of  obtaining  the  desired  shade  by  incorporating  pigment  in  the 
melted  or  dissolved  mixture.  Nitrogenous  animal  matter  must  be  avoided. 
8.  Waterproofing  Duplex  Fabrics. — These  rarely  have  a  water-repellent 
surface,  and  usually  wet  through  to  the  central  coating.  As  regards  the 
adhesive  substance  used,  it  must  have  much  the  same  properties  as  the 
impregnation  used  on  single  fabrics.  Rubberised  goods,  rubber-coated 
goods,  and  film-coated  goods  of  all  sorts  generally  are  not  so  much  water- 
proof in  the  sense  that  we  are  considering  as  they  are  coated.  This  dis- 
tinction is  usually  made  between  ''  waterproofed  "  fabrics,  or  integral 
waterproofing,  and  "  coated  "  goods,  either  those  having  the  superficial 
faces  of  the  goods  coated  with  similar  or  dissimilar  films,  or  those  where 
two  different  fabrics  each  have  one  face  coated  and  are  then  stuck  together, 
as  in  the  type  of  the  familiar  raincoat  and  automobile  top  fabrics  known 
as  "  bonded  "  fabrics.  In  the  better  grades  of  these  the  outer  surface  may 
be  mohair  or  worsted  and  the  inner  surface  a  cotton  twill  or  similar  fabric. 
The  material  used  must  not  dry  up  in  service  and  permit  of  the  separation 
of  the  two  fabrics.  If  a  light  fabric  is  used  for  one  face,  the  cloth  produced 
has  a  water-repellent  surface  which  can  be  turned  upward.  The  double 
cloths,  in  all  probability,  can  be  used  most  economically  in  competition 
with  the  single  canvases  only  for  such  uses  as  truck  covers.  Exposed  to 
summer  sun  and  heat,  many  substances  rapidly  decompose,  and  this 
fact  must  be  considered,  and  the  stability  of  the  adhesive  used  determined 
either  by  a  roof  test  or  exposure  to  a  dye-fading  lamp  rich  in  actinic  rays. 

9.  The  Cuprammoiiium  Process.^ — The  cuprammonium  process,  and 
other  processes  which  depend  for  their  effectiveness  on  the  partial  solution 
of  the  fiber,  followed  by  precipitation  as  a  continuous  film,  have  been 
made  to  give  very  satisfactory  canvases  for  this  use.  The  principle  of  the 
process  is  rather  simple,  and  generally  understood.  It  is,  unfortunately, 
very  expensive,  and  while  the  fabrics  prepared  by  it  are  durable  and  quite 
waterproof,  it  has  not  as  yet  been  thoroughly  proved  that  its  advantages 
are  sufficient  to  warrant  its  substitution  for  the  other  processes.  The 
prices  quoted  have  been  from  three  to  five  times  those  quoted  for  the 
paraffin,  rosin,  asphaltum,  etc.,  canvases. 

One  serious  objection  to  the  cuprammonium  process  has  been  that  the 
resulting  fabrics  are  harsh  and  hard  to  work  with  in  the  operations  of 

'  This  is  known  as  the  Willesden  finLsh.  The  treating  Hquor  is  prepared  as  follows: 
A  cold  solution  of  sulfate  of  copper  is  precipitated  with  the  exact  amount  of  caustic 
soda  necessary  or  slightly  less.  The  temperature  must  be  kept  below  20°  C.  or 
the  precipitate  will  be  black  instead  of  blue,  and  the  leaving  of  a  small  excess  of  copper 
sulfate  is  an  additional  precaution  against  this.  The  precipitate  is  washed  with  con- 
densed water  till  the  washings  give  no  precipitate  or  next  to  none,  with  chloride  of 
barium.  This  precipitate  is  then  pressed  to  get  rid  of  most  of  the  water,  and  dissolved 
in  just  enough  ammonia  of  sp.  gr.  0.93. 


566     CHEMICAL  TREATMENT  OF   FABRICS   FOR  WATERPROOFING 

stitching  together  in  the  desired  form  for  use.  There  is  also  a  tendency 
for  these  fabrics  to  give  off,  in  handhng,  an  irritating  dust.  A  very  great 
advantage  is  the  almost  complete  freedom  from  a  tendency  to  mildew, 
secured  by  the  retained  copper.  Clark  has  exposed  samples  of  this  kind 
of  material  to  mildew  spores  for  weeks  at  a  time  without  their  developing 
any  growths  at  all. 

10.  The  Drying  Oil  Processes. — The  drying  oils  are  in  great  disfavor 
among  the  purchasing  agents  at  this  time  because  of  their  tendency  to 
spontaneous  combustion  and  inferior  permanence  under  the  action  of  the 
various  destructive  agencies  encountered  in  actual  use.  Some  use  various 
drying  oil  mixtures,  and  others  use  compounds  of  so-called  vulcanised  oils 
based  on  the  reaction  between  various  oils  and  gums  and  chloride  of 
sulfur.  Chloride  of  sulfur  will  unite  with  many  of  such  compounds — 
linseed  oil,  rapeseed  oil,  corn  oil,  cottonseed  oil,  and  so  on,  forming  various 
solid,  semi-solid  or  liquid  products,  some  of  which  can  be  thinned  with 
volatile  solvents  and  compounded  with  fillers  and  colors  to  a  consistence 
suitable  to  spread  or  coat.  It  is  also  possible  to  make  thickened  mixtures 
of  the  oils  themselves  and  to  vulcanise  them  by  using  a  solvent  or  vapor 
carrying  chloride  of  sulfur  to  the  previously  unvulcanised  oil.  Both  these 
methods  are  used  with  various  degrees  of  success  but  in  most  cases  it  has 
been  found  difficult  to  control  the  quality  of  the  resulting  product.  It  is 
by  no  means  certain  that  it  is  practicable  to  attempt  to  secure  the  water- 
proofing of  heavy  canvas  by  the  formation  of  a  film  such  as  the  use  of 
linseed  oil  and  its  substitutes  produces.  Such  films  almost  invariably 
crack  on  repeated  creasing,  and  show  rather  inferior  stability  in  sunlight. 

11.  Use  of  Cellulose  Solutions. — Solutions  of  cellulose  acetate  and 
pyroxylin  (gun-cotton)  are  sometimes  employed  for  purposes  of  water- 
proofing cotton  fabrics,  but  neither  of  these  is  well  adapted  for  water- 
proofing by  saturation.  However,  a  certain  amount  of  the  latter  is  used  in 
a  semi-saturated  fabric  for  sanitary  sheeting,  dress  shields,  and  similar 
work.  The  cost  of  these  solutions  renders  them  unsuitable  for  rougher 
classes  of  work  and  limits  their  use  to  fields  where  the  appearance  and 
surface  of  the  materials,  or  their  ability  to  imitate  other  more  expensive 
material,  is  more  important  than  the  actual  waterproofing  or  protection 
of  surfaces. 

Pyroxylin  solutions  are  extensively  employed  for  the  coating  of  fabrics 
in  the  production  of  artificial  leathers,  which  are  now  so  widely  used  for  a 
variety  of  purposes.  Solutions  of  cellulose  acetate  have  been  successfully 
applied  to  the  coating  of  aeroplane  fabrics,  as  they  give  a  very  flexible 
yet  hornlike  coating  that  is  very  desirable  on  this  class  of  material. 

12.  Electrolytic  Method  of  Waterproofing. — A  rather  recent  yet  very 
successful  method  of  waterproofing  all  kinds  of  fabrics  consists  in  the 
electrolytical   precipitation   of  an  aluminium   soap  on   the  fiber.     The 


ELECTROLYTIC   METHOD   OF  WATERPROOFING 


567 


fabric  to  be  treated  is  first  impregnated  with  a  solution  of  sodium  oleate  ^ 
and  is  then  passed  through  a  bath  of  aluminium  acetate  through  which  an 
electric  current  is  passing.  The  electrolysis  of  the  aluminium  acetate  solu- 
tion in  the  presence  of  the  fiber  containing  the  sodium  oleate  causes  an 
electro-osmosis  of  the  waterproofing  agent  which  is  supposed  to  penetrate 
into  the  interstices  of  the  fiber  rather  than  simply  furnish  a  coating  on  the 
outside.  This  method,  known  as  the  Tate  process,  has  been  very  suc- 
cessfully operated  in  America  on  a  large  scale  on  wool,  silk,  and  cotton 
fabrics.^     The  machine  used  for  this  process  is  shown  in  Fig.  215.     The 


Fig.  215. — Tate  Apparatus  for  Electrolytic  Waterproofing. 


fabric  is  first  passed  through  a  very  dilute  bath  of  sodium  oleate  in  two 
tanks  with  squeeze  rolls  between.  The  fabric,  thus  impregnated  with  the 
soap  solution,  is  then  passed  between  the  anode  and  cathode  of  the  water- 
proofing section.  The  anode  consists  of  laminated  aluminium  bars  bolted 
together  and  covered  with  a  heavy  woolen  pad.  The  cathode  consists  of 
eight  Acheson  graphite  bars  against  which  the  cloth  is  pressed  while 
moving  through  the  apparatus.  The  solution  of  aluminium  acetate  is 
fed  into  the  troughs  between  the  graphite  bars  and  continually  trickles 
down  through  the  perforations,  wetting  the  fabric  thoroughly  while  the 

^  Sodium  palmitate  and  sodium  .stearate  have  also  been  tried,  but  the  oleate  gives 
the  best  results. 

2  See  Color  Trade  Journal,  1922,  p.  3. 


568     CHEMICAL  TREATMENT  OF  FABRICS  FOR  WATERPROOFING 

current  is  passing  between  the  electrodes  and  thus  through  the  cloth. 
The  electrolytic  treatment  requires  a  current  density  of  30  to  60  amperes 
and  a  voltage  of  50.  The  waterproofing  compound  that  is  formed  is  a 
basic  oleate  of  aluminium,  and  this  has  the  special  advantage  of  permitting 
the  cloth  to  be  dry  cleaned  without  losing  its  water-resisting  properties, 
which  is  not  the  case  with  the  neutral  oleate. 

13.  Waterproofing  with  Rubber  Latex. — Another  method  of  water- 
proofing rather  recently  introduced  is  the  use  of  the  natural  rubber 
latex.  Rubber  as  obtained  from  the  trees  is  in  the  form  of  a  milky 
emulsion  known  as  latex.  This  latex  is  now  imported  directly,  and 
before  the  separation  of  the  insoluble  rubber  material  it  may  be  employed 
for  impregnating  cotton  or  other  fabrics.  The  rubber  is  then  precipitated 
out  and  vulcanised  in  situ.  In  this  manner  the  fiber  is  not  only  coated 
with  the  rubber  but  is  completely  penetrated  by  it,  forming  a  highly 
waterproof  fabric.  While  this  method  has  been  chiefly  employed  in  the 
preparation  of  fabrics  for  automobile  tires,  it  has  also  been  extended 
to  the  making  of  certain  kinds  of  waterproof  fabrics. 

14.  Flame-proofing  of  Cotton  Fabrics. — The  rather  highly  inflam- 
mable nature  of  cotton  fabrics  as  compared  with  woolen  has  frequently 
been  an  obstacle  to  their  use  for  many  purposes.  Cotton  garments  made 
from  napped  or  fleeced  cotton  cloth  such  as  flannelette  has  often  been  the 
cause  of  severe  accidents  owing  to  its  inflammable  nature.  The  same 
is  true  of  the  use  of  cotton  for  theatrical  costumes  and  hangings,  lace 
curtains,  etc.  It  has  been  found  possible  to  reduce  greatly  the  inflam- 
mable nature  of  cotton  by  treatment  of  the  fiber  with  various  metallic 
salts.  Compounds  of  ammonium  have  been  largely  employed  for  this 
purpose.  A  solution  highly  recommended  for  this  purpose  is  composed 
of:  3  parts  ammonium  phosphate,  2  parts  ammonium  chloride,  2  parts 
ammonium  sulfate,  40  parts  water.  The  cloth  may  either  be  impregnated 
with  this  solution  or  the  starch  size  may  be  made  up  with  it.  The  vola- 
tility of  these  compounds  when  subjected  to  a  high  temperature  causes 
a  layer  of  inert  gas  to  form  around  the  fiber,  and  thus  prevents  it  from 
flaming.  Alum  mbced  with  the  sizing  of  cotton  goods  also  materially 
reduces  their  liability  to  catch  fire.  Borax  and  sodium  tungstate  have 
also  been  extensively  employed  for  the  same  purpose.  All  of  these  salts, 
however,  have  the  bad  effect  of  being  very  soluble,  consequently  the  non- 
inflammable  property  they  give  to  the  cotton  is  removed  when  the  material 
is  washed. 

15.  Perkin's  Process. — Perkin  has  found  that  a  permanent  treatment 
may  be  given  the  cotton  by  impregnating  the  cloth  with  a  solution  of 
sodium  stannate  (45°  Tw.),  squeezing,  drying  over  hot  rolls,  and  then 
treating  with  a  solution  of  ammonium  sulfate  (15°  Tw.).  The  fabric 
is  then  dried  a  second  time  and  then  washed  to  remove  the  sodium  sulfate 


ACTION  OF  VARIOUS  SALTS  IN   FIREPROOFING  569 

formed  in  the  reaction,  leaving  in  the  fiber  precipitated  stannic  oxide. 
This  is  known  as  the  "  Non-Flam  "  process  and  is  the  subject  of  a  number 
of  patents.  This  treatment  makes  the  fabric  quite  non-inflammable,  and 
this  property  is  permanent  against  repeated  washings.  It  also  leaves  the 
fiber  soft  to  the  feel  and  does  not  reduce  its  tensile  strength. 

The  Perkin  process  of  fireproofing  has  been  used  considerably  in 
England,  particularly  for  the  treatment  of  flannelette;  the  considerable 
cost  of  the  process,  however,  seems  to  have  prevented  its  adoption  in 
America.  Nanson  states  that  all  goods  padded  with  tin  preparations 
must  be  heavily  squeezed  after  passing  through  the  liquor.  Just  what 
action  this  causes  is  not  clear,  but  it  seems  that  the  heavy  pressure 
increases  the  affinity  of  the  cloth  for  the  tin  oxide,  with  the  consequent 
deposition  of  more  tin  oxide  on  the  goods. 

16.  Action  of  Various  Salts  in  Fireproofing. — Konig  ^  states  that 
textile  fabrics  cannot  be  rendered  absolutely  non-inflammable,  but  may 
by  suitable  treatment  be  so  changed  that  when  exposed  to  a  flame  they 
do  not  take  fire,  but  simply  char.  The  various  impregnating  salts  that 
are  ordinarily  employed  act  in  different  ways.  Some  volatilise  at  a  high 
temperature,  yielding  vapors  which  extinguish  the  flame,  while  others 
melt,  forming  a  vitreous  covering  for  the  fiber  which  prevents  further 
combustion.  To  the  former  class  belong  the  salts  of  ammonium,  such 
as  the  sulfate.  The  latter  salt,  however,  is  objectionable  on  account  of 
the  disagreeable  nature  of  the  smoke  that  it  generates.  Ammonium 
chloride  acts  in  similar  manner  but  it  is  necessary  to  use  a  solution  con- 
taining at  least  15  percent  of  the  salt  to  get  good  results,  and  of  sub- 
stances tried,  Konig  states  this  to  be  the  worst.  In  the  second  class  of 
salts  available  for  flame-proofing  there  may  be  especially  mentioned  silicate 
of  soda,  borax,  and  phosphate  of  soda.  Silicate  of  soda  has  the  disad- 
vantage of  imparting  to  the  fabric  considerable  stiffness,  and  hence  cannot 
be  applied  to  goods  with  a  soft  finish.  Good  results  are  obtained  by  the 
use  of  borax  or  a  mixture  of  borax  and  sodium  phosphate,  though  it  is 
found  to  be  better  to  add  also  some  glucose  to  the  mixture.  The  latter 
prevents  the  salts  from  crystallising  on  the  fabric  when  drying  and  thus 
allows  of  a  better  penetration  and  impregnation.  Ammonium  phosphate 
may  also  be  used  as  this  combines  both  volatility  and  the  vitreous  melt 
and  is  said  to  give  very  good  results.  Other  substances,  such  as  the  salts 
of  vanadium,  tungsten  and  molybdenum,  are  not  volatile  and  do  not 
form  a  melt,  but  thej^  thoroughly  penetrate  the  fiber  and  mineralise,  as 
it  were,  without  making  the  fabric  stiff  or  brittle.  Tungstate  of  soda  is 
especially  employed  for  fine  fabrics.  All  of  these  methods,  however, 
have  the  defect  that  the  fireproofing  salts  are  removed  when  the  fabric 
is  washed. 

^  Oest,  Wollen  <fc  Leinen  Ind.,  1900. 


570     CHEMICAL  TREATMENT   OF   FABRICS   FOR  WATERPROOFING 

Holden  ^  has  studied  the  influence  of  various  dyeing  and  mordanting 
operations  on  the  combustibihty  of  cotton  goods.  He  finds  that  the 
presence  of  iron,  chromium,  lead  or  copper  compounds  increases  the  rate 
of  burning  of  cotton  fabrics;  dyeing  with  substantive  and  sulfur  colors, 
even  when  the  dyed  goods  are  after-treated  with  copper  sulfate  or  chrome, 
exerts  no  appreciable  influence.  The  following  table  gives  the  results 
of  the  various  tests: 

Relative  Degrees  of  the  Influence  of  Dyeing  on  the  Combustibility  of  Cotton 


Accelerating 
Influence. 

No  Appreciable 
Influence. 

Retarding  Influence. 

Tannin  with  iron 

Scoured  cloth 

Tannin  with  aluminium 

Tannin  with  copper 

Tannin  alone 

— 

Tannin  with  manganese 

Tannin  with  tin 

— 

Tannin  with  lead 

Tannin  with  antimony 

— 

Tannin  with  chromium 

— 

— 

Logwood  with  iron 

Logwood  alone 

Logwood  with  aluminium 

Cutch  with  iron 

Cutch  alone 

Cutch  with  aluminium 

Cutch  with  copper 

— 

— 

Cutch  with  chromium 

— 

— 

Fustic  with  iron 

Fustic  alone 

Fustic  with  aluminium 

Fustic  with  copper 

— 

— 

Fustic  with  chromium 

— 

— 

Iron  buff 

Substantive  dyes  alone 

Alizarine  with  aluminium 

Khaki 

Substantive  dyes  coppered 

— ■ 

Chrome  green 

Substantive  dyes  chromed 

Alizarine  with  tin  and  aluminium 

Prussiate  blue 

Sulfur  dyes  alone 

— 

Manganese  bronze 

Sulfur  dyes  coppered 

— 

Chrome  yellow 

Sulfur  dyes  chromed 

— 

Chrome  orange 

— 

— 

AUzarine  with  iron 

— 

— 

Alizarine  with  chromium 

— 

— 

Aniline  black 

— 

— 

17.  Preparation  of  Various  Fireproofing  Compounds. — The  various 
stages  in  the  development  of  fireproofing  may  be  enumerated  as  follows: 
Arfird,  in  1876,  recommended  the  saturation  of  cotton  goods  with  phosphate 
of  ammonia,  but  without  any  notable  results.  Fuchs,  in  1820,  first  used 
water-glass  (silicate  of  soda),  and  in  1821  Gay-Lussac  obtained  good  results 
by  its  use.  They  observed  that  those  chemicals  which,  under  the  action  of 
a  little  heat,  would  melt  and  glaze  the  fibers,  as  with  borax,  for  instance, 
were  the  most  suitable  for  the  purpose.     Later,  borate  of  ammonia  and 

'  Jour.  Soc.  Dyers  tfc  Col,  1918,  p.  7. 


PREPARATION   OF   VARIOUS   FIREPROOFING   COMPOUNDS     571 

phosphate  of  ammonia  alone,  or  with  addition  of  sai  ammoniac,  were 
extensively  used.  Morin  recommended  zinc  oxide;  Masson,  the  double 
salt  of  chloride  and  acetate  of  calcium.  Equal  parts  of  these  two  chemicals 
were  dissolved  together  in  warm  ammonia  water.  Doebereiner,  speaking 
of  the  easy  inflammability  of  fabrics,  mentioned  borax,  water-glass,  alum, 
and  phosphate  of  ammonia.  W.  H,  Perkin  observed  that  a  solution  of 
tungstate  of  soda,  salts  of  alumina,  and  a  sufficient  quantity  of  acetic 
or  formic  acid,  were  very  efficient  in  making  cotton  fireproof. 

Perkin  recommended  the  following  proportions  (parts  by  volume) : 

1.  Aluminium  sulfate  sol.  20°  Be 100 

Acetic  acid  7°  Be 25 

Tungstate  soda  sol.  31°  Be 200 

2.  Acetate  alumina  16°  Be 100 

Acetic  acid  7°  Be 10 

Tungstate  soda  sol.  31°  Be 200 

3.  Aluminium  sulfate  16°  Be 100 

Acetic  acid  7°  Be 30 

Tungstate  soda  33°  Be 150 

4.  Aluminium  sulfate  16°  Be 100 

Formic  acid  7°  Be 40 

Tungstate  soda  33°  Be 150 

The  first  two  ingredients  are  mixed,  and  then  the  tungstate  is  added 
in  a  thin  stream,  the  mixture  being  well  stirred  meanwhile,  so  that  the 
precipitate  first  formed  will  redissolve  easily.  The  goods  are  well  satur- 
ated, then  allowed  to  lie  for  one  hour.  They  are  then  dried,  steamed,  and 
calendered.  The  organic  acid  evaporates  and  leaves  the  insoluble  pre- 
cipitate of  fireproofing  material  on  the  fiber. 

The  following  processes  have  found  wide  application  in  actual  practice : 

(a)  Thouret  impregnates  the  goods  with  either  3  parts  phosphate  ammonia  or 
2  parts  phosphate  ammonia,  1  part  sal  ammoniac,  and  a  Httle  calcium  chloride,  in 
45  parts  of  water,  the  different  strengths  being  used  on  various  grades  of  work. 

(b)  NicoU  takes  6  parts  alum,  2  parts  borax,  1  part  tungstate  of  soda,  1  part 
dextrin  in  soapy  water.     Dextrin  facilitates  the  taking-up  of  the  .salts  by  the  fabric. 

(c)  Martin  uses  8  lbs.  sulfate  of  ammonia,  2.5  lbs.  carbonate  of  ammonia,  30  lbs. 
boric  acid,  2  lbs.  borax,  and  2  lbs.  of  starch  in  100  liters  of  water.  This  preparation 
serves  well  for  light  fabrics.  They  are  impregnated  at  about  100°  F.,  then  dried  and 
pressed. 

(d)  Another  good  preparation  is  made  by  taking  12  lbs.  alum,  4  lbs.  borax,  4  lbs. 
phosphate  of  soda,  4  lbs.  tungstate  soda,  and  2  lbs.  sulfate  ammonia.  These  are  all 
finely  powdered  and  mixed  well.  Over  this  mixture  there  is  poured  caustic  soda  lye 
of  36°  Be.,  until  a  milky  solution  results.  This  is  boiled  until  it  will  produce  a  blue 
precipitate  on  a  piece  of  wood.  The  goods  are  impregnated  with  this  in  a  boiling-hot 
solution,  then  wrung  or  whizzed  uniformly,  and  dried  at  150°  F. 

(e)  A  starch  for  fireproofing  is  made  as  follows:  30  lbs.  tungstate  of  s  da,  30  lbs. 
borax,  and  60  lbs.  of  rice  or  wheat  starch  are  mixed  and  ground  thoroughly.  In  using 
it,  boil  up  as  with  ordinary  starch,  and  apply  in  the  usual  way. 


572     CHEMICAL   TREATMENT   OF   FABRICS   FOR   WATERPROOFING 

It  is  impossible  to  render  textile  fabrics  fireproof  without  leaving  the 
fireproofing  composition  on  the  fibers;  although  many  attempts  have  been 
made  to  change  the  nature  of  the  fiber  substances,  and  leave  it  non- 
combustible,  all  efforts  have  been  in  vain.  The  best  that  can  be  done 
is  to  treat  the  fabrics  with  some  substance  which  of  itself  is  non-inflamma- 
ble, and  which  protects  the  fiber  substance  in  such  a  manner  that  it  will 
not  burst  into  flame  when  fire  is  near. 

The  following  formula  for  a  fireproofing  compound  for  textiles  has 
been  found  to  prevent  the  fabric  from  bursting  into  flames  when  a  treated 
and  dried  piece  of  lace  curtain  material  was  suspended  over  an  alcohol 
lamp;  the  only  result  was  that  the  fabric  became  charred  and  disintegrated. 

Sulfate  of  ammonia 8  lbs. 

Borax 2  " 

Boric  acid 3  " 

Carbonate  of  ammonia 2  " 

Dextrin 5  ozs. 

Water to  make  15  gals. 

The  material  to  be  "  proofed  "  is  simply  immersed  in  the  solution  until 
thoroughly  saturated,  then  squeezed  and  dried.  This  quantity  of  solution 
is  sufficient  to  treat  100  lbs.  of  textiles. 

Another,  though  similar,  solution  is  prepared  as  follows: 

Sulfate  of  ammonia 15  lbs. 

Borax 3  " 

Boric  acid 3  " 

Water to  make  15  gals. 

The  material  is  simply  immersed  until  saturated,  then  lifted,  squeezed, 
and  dried. 

A  starch  for  sizing  purposes  may  be  made  according  to  the  following 
formula,  and  the  starch  may  be  replaced  by  either  flour,  sago,  dextrin, 
or  other  similar  substance. 


Starch 55    lbs. 

Tungstate  of  soda 27^  " 

Borax 17i  " 


For  use,  this  compound  is  made  into  starch  or  size  of  proper  consistency, 
applied  to  yarns  or  fabrics  in  the  usual  manner,  and  dried. 

According  to  E.  Duhem,  the  following  list  gives  the  minimum  quantity 
of  each  substance  required  to  render  100  parts  of  cotton  flame-proof: 


EFFECTIVENESS  OF  FIREPROOFING  AGENTS  573 

^  ,  Parts  by 

Reagent.  ^^.^^^ 

Tungstate  of  ammonia 12 

Sulfate  of  ammonia 4^ 

Phosphate  of  soda 30 

Chloride  of  sodium  (common  salt) 35 

Phosphate  of  lime 30 

Phosphate  of  magnesia 30 

Chloride  of  magnesium 4-5 

Phosphate  of  zinc 20 

Sulfate  of  zinc 4| 

Borate  of  alumina 24 

Alumina  hydrate 3 

Chloride  of  ammonium 4| 

Phosphate  of  ammonia 42- 

Silicate  of  soda 50 

Borax 85 

Chloride  of  calcium 45 

Sulfate  of  magnesia 15 

Cliloride  of  potassium 45 

Borate  of  zinc 20 

Phosphate  of  alumina 30 

Boric  acid 10 

Silicic  acid 30 

The  proportions  and  quantities  vary  with  the  kind  of  goods:  10  percent 
for  delicate  fabrics  such  as  lace;  15  percent  for  heavy  fabrics;  20  percent 
for  buckram  intended  for  stage  curtains. 

18.  Effectiveness  of  Fireproofing  Agents. — W.  B.  Nanson  states 
(Cotton)  that  in  studying  the  effects  of  various  salts  on  the  combustibility 
of  textiles,  it  has  been  found  that  the  most  effective  are  the  ammonium 
salts,  and  zinc,  tin,  borax,  boracic  acid,  and  aluminium,  the  last  in  the 
form  of  a  precipitate  of  aluminate  of  soda  with  an  ammonium  salt.  The 
zinc,  tin,  and  alum  in  conjunction  with  the  ammonium  salts  have  given 
the  best  and  most  permanent  results.  The  ammoniacal  salts,  volatilising 
under  the  influence  of  heat,  form  mixtures  with  the  oxygen  of  the  air 
and  other  combustible  gases  which  are  completely  incombustible,  the 
former  of  which  combine  with  the  fabric,  while  the  latter  forms  an  inert  and 
non-inflammable  atmosphere  in  which  nothing  will  burn.  The  action  of 
tin,  aluminium,  zinc,  tungstates,  and  borates  is  a  purely  mechanical  one; 
they  simply  receive,  conduct,  and  radiate  the  heat,  so  that  at  no  time  is 
the  fabric  itself  able  to  keep  up  and  perpetuate  its  own  kindling  tempera- 
ture, but  when  exposed  to  flame  from  other  sources  than  itself,  it  simply 
smolders,  blackens,  and  chars  without  bursting  into  flame.  In  other 
words,  they  are  fire-resisting  and  slow-burning  because  their  presence 
raises  the  kindling  temperature  of  the  fabric  above  that  of  the  flame 
being  applied  to  them,  and  with  the  possible  exception  of  tin  and  alumina 


574     CHEMICAL  TREATMENT   OF   FABRICS   FOR   WATERPROOFING 

their  efficacy  is  short-lived.  This  appHes  to  ammoniacal  salts  also;  they 
either  dust  out  or  wash  out,  and  must  be  renewed  frequently.  The 
oxides  of  tin,  iron,  and  tungsten  possess  great  fire-resisting  possibilities 
but  they  have  their  limitations:  tin  and  tungsten  are  expensive  and  iron 
is  colored  and  therefore  impracticable  unless  a  buff  color  is  permissible. 
Alumina,  as  we  shall  show  later  on,  may  be  converted  into  an  insoluble 
flame-proof  compound  and  used  with  measureable  success. 

Peroxide  of  tin  is  applied  to  the  cloth  in  the  state  of  a  soluble  combina- 
tion of  sodium  hydrate  and  oxide  of  tin,  known  as  stannate  of  soda,  and 
may  be  obtained  by  adding  a  solution  of  caustic  soda  to  a  solution  of 
perchloride  of  tin,  until  the  precipitate  at  first  formed  is  entirely  redis- 
solved.  If  a  piece  of  cotton  cloth  impregnated  with  such  a  solution  is 
dipped  in  a  solution  of  chloride  or  sulfate  of  ammonia  or  dilute  sulfuric 
acid  the  alkaline  combination  of  tin  and  soda  is  decomposed,  and  peroxide 
of  tin  is  precipitated  within  the  fiber. 

The  efficacy  of  peroxide  of  tin  as  a  flame-proofing  agent  arises  from 
the  fact  that  the  fiber  has  such  a  strong  affinity  for  the  tin  oxide  that  it 
becomes  a  part  of  it,  and  the  effect  is  thus  rendered  permanent;  further, 
the  tin  oxide,  being  at  its  highest  state  of  oxidation,  cannot  combine  with 
more  oxygen  and  take  fire. 

Another  tin  process  is  given  by  Nanson  as  follows:  Steep  the  goods 
for  one  hour  in  stannate  of  soda  at  20°  Tw.,  squeeze  heavily  and  dry. 
After  drying,  run  through  a  bath  composed  of  chloride  of  ammonia  and 
acetate  of  zinc  at  17°  Tw.  and  dry  without  washing. 

In  the  Melauny  process,  which  is  highly  eulogised  by  the  French 
authorities,  the  cotton  is  run  through  a  solution  of  stannate  of  soda  at 
from  5°  to  10°  Be.  and  dried.  It  is  then  run  through  a  solution  of  a 
titanium  salt.  Any  soluble  titanium  salt  will  answer,  but  Nanson  suggests 
the  chloride.  This  solution  should  be  so  constituted  that  each  liter  may 
contain  about  62  grams  of  titanium  oxide.  The  fabric  is  again  dried  and 
the  titanium  salt  is  ultimately  fixed  by  means  of  an  alkaline  bath.  It  is 
advantageous  to  employ,  for  this  purpose,  a  solution  of  silicate  of  soda 
of  about  12°  to  15°  Tw.,  or  a  mixture  of  tungstate  of  soda  and  ammonium 
chloride  may  be  used.  The  fabric  is  afterward  washed.  The  goods  may 
also  be  treated,  after  the  stannate,  with  a  mixed  bath  containing  titanium, 
tungsten,  and  a  suitable  solvent. 

In  place  of  stannate  of  soda,  which  is  expensive  as  a  flame-resisting 
agent,  Nanson  suggests  the  analogous  salt  of  alumina.  It  is  cheaper  and 
its  fireproofing  properties  are  equally  valuable.  It  has  been  used  under 
the  name  of  alumin,  and,  being  at  its  highest  degree  of  oxidation  and 
therefore  incapable  of  further  oxidation,  it  cannot  burn.  Moreover,  as 
it  is  an  insoluble  hydrate,  it  acts  in  a  purely  mechanical  way  by  rendering 
the  goods  non-inflammable  in  themselves,  while  the  subsequent  treatment 


EFFECTIVENESS  OF  FIREPROOFING  AGENTS  575 

with  ammonium  chloride,  which  volatiHses  at  a  red  heat,  affords  its  usual 
gaseous  protection  as  explained  above.  Aluminate  of  soda,  or  "  alumin  "  as 
it  is  called,  may  be  made  by  dissolving  powdered  alum  in  a  solution  of 
caustic  soda  until  it  becomes  saturated  or  until  a  precipitate  begins  to 
reform.  The  fabric  is  run  through  this  at  about  15°  to  20°  Tw.,  and 
dried;  during  the  operation  of  drying  the  carbonic  acid  of  the  air  seizes 
upon  the  caustic  soda  which  holds  the  alumina  in  solution,  causing  the 
formation  of  carbonate  of  soda  and  the  precipitation  of  the  aluminium 
hydrate.  The  time  consumed  in  drying,  however,  is  seldom  sufficiently 
prolonged  to  allow  of  the  complete  decomposition  of  the  aluminate  of  soda. 
This  is  insured  by  afterward  passing  the  goods  through  a  dilute  solution 
of  chloride  of  ammonium,  which  immediately  determines  the  complete 
precipitation  of  the  alumin. 

Sulfate  of  ammonia  may  be  used  for  flame-proofing,  as  may  also  the 
chloride.  One  of  the  cheapest  methods  for  rendering  cotton  goods  flame- 
and  spark-proof,  and  one  which  is  often  used  on  awning  goods,  is  to  pad 
the  goods  in  a  boiling  solution  composed  of  60  gals,  of  water,  16  lbs.  of 
acetate  of  lead,  and  12  lbs.  of  sulfate  of  zinc,  allow  the  goods  to  he  over- 
night in  this  without  drying  and  then  repeat  in  the  morning  and  dry. 
After  the  goods  are  cooled  off,  run  through  a  solution  of  alum,  using  one-half 
pound  of  alum  to  each  gallon  of  water.  The  goods  are  dried  up  from  this 
without  rinsing.  Tungstate  of  soda  is  used  in  the  laundries  of  Europe 
on  fine  laces  as  a  fireproofing  agent  but  is  expensive  for  commercial  use 
and  is  not  permanent. 

One  of  the  best  ammonia  compounds  for  fire-resisting  purposes  is 
phosphate  of  ammonia,  which  is  very  effective  and  possesses  the  added 
merit  of  simplicity.  If  a  textile  is  steeped  in  a  10  percent  solution  of 
phosphate  of  ammonia  and  dried,  the  kindling  temperature  of  the  fabric 
so  treated  is  raised  to  such  a  point  that  when  fire  is  applied  to  it  the  rapid 
evolution  of  carbonic  acid  and  ammonia  renders  the  textile  non-inflam- 
mable by  the  mechanical  union  of  the  phosphoric  acid  with  the  fiber. 
Besides  producing  this  effect  upon  the  fabric  itself,  the  two  gases,  being 
incombustible,  surround  the  fabric  with  an  atmosphere  containing  no 
free  oxygen,  and  consequently  of  a  non-inflammable  character.  This 
process  stiffens  the  goods  considerably,  but  they  become  charred  only 
and  do  not  readily  flame  up  when  exposed  to  fire.  This  process  will  not 
stand  washing  or  water,  however. 

Another  process  by  which  the  phosphoric  acid  and  ammonia  may  be 
utilised  for  fireproofing  is  by  the  fixation  of  an  insoluble  magnesium — 
ammonium  phosphate  precipitated  on  the  fibers.  The  material  is  first 
padded  in  a  concentrated  solution  of  a  soluble  phosphate,  preferably 
the  mono-calcium  salt,  and  dried.  It  is  then  passed  through  an  ammo- 
niacal  solution  of  magnesium  chloride  composed  of  ammonia,  chloride  of 


576     CHEMICAL  TREATMENT   OF  FABRICS   FOR  WATERPROOFING 


ammonia,  and  sulfate  of  magnesia.  Ammonium  phosphate  is  thus  pre- 
cipitated on,  and  in,  the  fiber,  and  after  rinsing  in  a  very  dikited  ammonir 
water,  and  drying,  the  material  is  practically  non-inflammable.  This 
property  is  only  slightly  affected  by  rubbing  or  washing.  In  making  an 
ammoniacal  solution  of  magnesium  chloride  it  must  be  remembered  that 
magnesium  hydrate  is  soluble  in  a  solution  of  chloride  of  ammonium,  and 
that  ammonia  produces  no  precipitate  in  a  solution  of  magnesia  containing 
an  excess  of  chloride  of  ammonia;  therefore,  care  must  be  taken  that 
sufficient  chloride  of  ammonia  is  present  to  prevent  the  precipitation  of 
the  hydrate.     The  light  rinsing  after  this  operation  in  weak  ammonia 

water  serves  to  com- 
plete the  process 
by  precipitating  any 
hydrate  that  may 
be  uncombined  with 
the  fabric  and  wash- 
ing off  all  loose 
particles  of  the  hy- 
drate. 

For  rendering 
fabrics  non-inflam- 
mable by  means  of 
starch  compounds, 
the  following  mix- 
ture may  be  com- 
mended: 10  parts 
hyposulfite  of  soda 
(granulated) ;  10 
parts  cornstarch,  10 
parts  common  salt, 
5  parts  borax,  and 
10  parts  magnesium  hydrate  (talc).  These  must  be  well  ground 
together  so  as  to  be  thoroughly  incorporated,  the  necessary  water  added 
according  to  stiffness  required,  and  all  boiled  together.  This  is  an  entirely 
mechanical  process  and  is  not  permanent. 

The  French  Academy  of  Sciences  has  awarded  a  medal  of  honor  for 
the  following  process  based  on  the  employment  of  salts  of  ammonia  as  a 
fireproofing  agent,  to  which  is  added  borax  and  boracic  acid :  8  lbs.  sulfate 
of  ammonia,  2.5  lbs.  carbonate  of  ammonia,  3  lbs.  boracic  acid,  8  lbs. 
borax,  2  lbs.  starch,  0.4  lb.  dextrin,  and  100  lbs.  of  water.  This  is 
applied  to  the  fabric  at  86°  F.  on  the  mangle  and  dried  on  the  dry 
cans. 

The  following  is  also  a  French  recipe:    15  lbs  chloride  of  ammonia, 


Fig.  216. — Mangle  for  Flameproofing  Cotton  Fabrics. 


EFFECTIVENESS  OF  FIREPROOFING  AGENTS  577 

6  lbs.  boracic  acid,  3  lbs.  borax  and  100  lbs.  of  water.  Neither  of  the  two 
foregoing  will  stand  washing  or  water. 

It  will  be  seen  from  all  that  has  been  said,  that  the  selection  of  the 
process  and  the  agents  used  depend  largely  upon  whether  the  goods  are 
required  to  stand  washing.  If  not,  as  is  usually  the  case  with  lace  goods, 
a  mixture  containing  one  or  more  of  the  following  bodies  may  be  used: 
metallic  oxides,  such  as  tin  or  alumina;  compounds  of  ammonium,  such 
as  the  chloride  or  phosphate;  sodium  phosphate,  borate,  silicate,  tung- 
state,  or  alum. 

In  many  cases  it  is  only  necessary  to  mix  the  materials  with  the  dressing 
mixture,  but  where  the  fireproofed  goods  have  to  stand  washing  or  out- 
door wear  and  tear,  the  fireproofing  again  must,  if  possible,  be  precipitated 
on  the  fiber  by  means  of  a  double  reaction  as  in  the  recipes  calling  for  the 
precipitation  of  tin  oxide  and  alumina  in  which  these  oxides  and  hydrates 
are  precipitated  on  the  goods  insolubly  by  means  of  a  double  decomposi- 
tion caused  by  the  application  of  ammonium  and  other  salts. 

Nanson  recommends  the  apparatus  shown  in  Fig.  216  for  the  treatment 
of  goods  to  be  fireproofed. 


CHAPTER  XIX 
MERCERISED  COTTON 

1.  Origin  of  Name. — Mercerising  is  a  term  applied  to  that  process 
whereby  cotton  is  treated  with  concentrated  caustic  alkahes.  In  its 
strictest  significance,  however,  it  refers  most  directly  to  the  process  of 
giving  cotton  a  high  degree  of  luster  by  subjecting  its  imultaneously  to 
the  chemical  action  of  caustic  alkalies  and  the  mechanical  action  of  tension 
sufficient  to  prevent  contraction.  The  process  is  named  from  John  Mercer, 
who  first  discovered  the  effect  of  strong  solutions  of  caustic  alkalies  on 
cotton  in  the  year  1844.  It  was  not  until  the  last  decade,  however,  that 
the  process  attained  any  degree  of  commercial  success;  but  during  the 
last  few  years  it  has  given  practically  a  new  fiber  to  the  textile  industry. 

2.  Early  Development  of  Process. — Mercer  took  out  a  patent  for  the 
process  in  1850,  and  he  describes  therein  practically  all  the  conditions 
of  mercerising  with  the  exception  of  that  of  tension. 

Mercer's  original  patent  is  so  important  in  connection  with  the 
treatment  of  cotton  not  only  with  strong  solutions  of  caustic  soda  but 
also  with  other  chemical  reagents,  that  it  will  be  of  interest  to  give  at  this 
point  the  chief  parts  of  the  patent,  which  are  as  follows : 

"My  invention  consists  in  subjecting  vegetable  fabrics  and  fibrous  materials, 
cotton,  flax,  etc.,  either  in  the  raw  or  the  manufactured  state,  to  the  action  of  caustic 
soda  or  caustic  potash,  dilute  sulfuric  acid  or  chloride  of  zinc,  of  a  strength  and  tem- 
perature sufficient  to  produce  the  new  effects  and  to  give  the  new  properties  which  I 
have  hereinafter  described. 

"The  mode  I  adopt  of  carrying  into  operation  my  invention  to  cloth  made  from 
any  vegetable  fiber  and  bleached,  is  as  follows:  I  pass  the  cloth  through  a  padding 
machine  charged  with  caustic  soda  or  caustic  potash  of  say  60°  to  70°  Tw.,  at  the 
common  temperature,  say  60°  F.  or  under,  and  without  drying  the  cloth  wash  it  in 
water,  and  then  pass  it  through  dilute  sulfuric  acid  and  wash  again;  or,  I  run  the 
cloth  over  and  under  a  series  of  rollers  in  a  cistern  with  caustic  potash  or  soda  of  from 
40°  to  50°  Tw.  at  the  common  atmospheric  temperature;  the  last  two  rollers  being  so 
set  as  to  squeeze  the  excess  of  potash  or  soda  back  into  the  cisterns;  the  cloth  then 
passes  over  and  under  rollers  placed  in  a  series  of  cisterns  charged  at  the  commence- 
ment of  the  operation  with  water  only,  so  that  at  the  last  cistern  the  alkali  has  been 
nearly  all  washed  out  of  the  cloth;  when  the  cloth  has  either  gone  through  the  padding 
machine  or  through  the  ci.sterns  above  described,  I  wa.sh  the  cloth  in  water,  pass  it 
through  dilute  sulfuric  acid,  and  again  wash  in  water. 

"When  I  adopt  the  invention  to  gray  or  unbleached  cloth  made  from  vegetable 
fibers,  I  first  boil  or  steep  the  cloth  in  water,  so  as  to  have  it  thoroughly  wet,  and 

578 


EARLY  DEVELOPMENT  OF   PROCESS  579 

remove  most  of  the  water  by  the  squeezer  or  hydroextractor,  and  then  pass  the  cloth 
through  the  soda  or  potash  solution  before  described. 

"I  apply  my  invention  in  the  same  way  to  warps,  either  bleached  or  unbleached, 
but  after  passing  through  the  cistern  containing  the  alkali,  the  warps  are  either  passed 
through  squeezers  or  through  a  hole  in  a  metalhc  plate  to  remove  the  alkali,  and 
then  passed  through  the  water  cistern,  soured  and  washed  as  before  described. 

"When  thread  or  hank  yarn  is  operated  upon,  I  immerse  the  thread  or  yarn  in 
the  alkali,  and  then  wring  out  as  is  usually  done  in  sizing  or  dyeing  them,  and  after- 
ward wash,  sour  and  wash  in  water  as  above  described. 

"When  cloth  made  from  vegetable  fiber,  cotton,  flax,  etc.,  has  been  subjected  to 
the  action  of  soda  or  potash  as  above  described,  by  padding,  immersion,  or  in  any 
other  way,  and  then  freed  from  alkali,  the  cloth  will  be  found  to  have  acquired  new 
and  valuable  properties,  the  more  remarkable  of  which  I  here  describe.  It  will  have 
shrunk  in  length  and  breadth,  or  have  been  made  less  in  external  dimensions  but 
thicker  and  closer,  so  that  by  the  chemical  action  of  soda  or  potash  I  produce  on  cotton 
or  other  vegetable  fibers  effects  somewhat  analogous  to  those  which  are  produced  on 
wool  by  the  processes  of  fulling  or  milHng.  It  will  have  acquired  greater  strength 
and  firmness,  each  fiber  requiring  greater  force  to  break  it.  It  will  also  have  become 
heavier  than  it  was  before  it  was  acted  upon  by  the  alkali.  It  will  have  acquired 
greatly  augmented  and  improved  powers  of  receiving  colors  in  printing  and  dyeing. 

"Secondly,  I  employ  sulfuric  acid  diluted  to  105°  Tw.,  and  at  60°  F.  or  under. 
I  use  this  acid  instead  of  soda  or  potash,  and  operate  in  all  respects  the  same  as  when 
I  use  soda  or  potash,  except  the  last  souring  which  is  here  unnecessary. 

"Thirdly,  when  I  employ  solutions  of  chloride  of  zinc,  instead  of  soda  or  potash, 
I  use  the  solution  at  145°  Tw.  and  at  150°  to  160°  F.,  and  operate  the  same  in  all 
respects  as  when  I  use  soda  or  potash. 

"When  I  operate  on  mixed  fabrics,  partly  of  vegetable  and  partly  of  silk,  wool, 
or  other  animal  fiber,  such  as  delaines,  I  prefer  the  strength  of  the  alkali  not 
to  be  over  40°  Tw.  and  the  heat  not  above  50°  F.,  lest  the  animal  fibers  should  be 
destroyed." 

Mercer  further  found  that  strong  solutions  of  calcium  chloride,  stan- 
nous chloride,  arsenic  acid,  or  phosphoric  acid  will  also  induce  the  mer- 
cerising effect,  but  are  less  active  and  more  troublesome  than  caustic 
alkali. 

Mercer  only  employed  the  process  for  increasing  the  solidity  and 
strength  of  cotton  fabrics — not  employing  tension  he  did  not  notice  very 
closely  the  increased  luster.  Persoz  in  his  Traite  de  V Impression  (1846) 
describes  a  method  of  dyeing  manganese  bronze  in  France  in  which 
caustic  soda  lye  of  35°  Be.  was  employed,  and  mentions  that  this  strength 
was  considered  necessary  to  produce  shrinkage  of  the  fabric.  The  action 
of  caustic  soda  on  cotton,  therefore,  as  far  as  contraction  is  concerned, 
seems  to  have  been  known  before  Mercer's  discovery  was  patented. 
Garnier  and  Depoully  in  1883  employed  the  process  for  producing  crepe 
by  using  caustic  soda  solutions  to  shrink  the  fabric  in  places.  Lowe  in 
1890  took  out  an  English  patent  describing  the  use  of  tension  during 
mercerisation  to  produce  a  luster.  The  combination  of  Mercer's  and 
Lowe's  patents  describe  in  detail  all  the  necessary  conditions  for  mercer- 


580  MERCERISED  COTTON 

ising  as  practised  at  the  present  time.  The  process  of  mercerising  has 
been  subject  to  a  great  number  of  patents,  especially  by  Thomas  and 
Prevost  of  Germany.  This  resulted  in  considerable  litigation  in  many 
countries.  As  far  as  the  actual  chemical  process  itself  is  concerned, 
however,  there  does  not  appear  to  have  been  any  material  advance 
beyond  the  facts  first  discovered  by  Mercer  and  patented  by  him  in  1850; 
with  regard  to  the  element  of  carrying  out  the  process  under  tension,  it 
may  be  said  that  this  was  first  described  and  patented  by  Arthue  Lowe 
in  1890,  and  this  included  the  application  of  tension  either  during  or  after 
the  treatment  with  caustic  alkali.  Lowe's  object  in  stretching  the  material, 
however,  was  primarily  to  prevent  the  loss  encountered  by  the  shrinkage 
of  the  goods,  though  he  does  also  make  a  specific  statement  that  the 
cotton  acquires  an  increased  luster  and  finish  by  the  process.  The  only 
novelty  put  forward  by  Thomas  and  Prevost  was  the  use  of  a  particular 
kind  of  cotton,  that  is,  long-stapled  varieties;  but  as  both  Mercer's  and 
Lowe's  patents  claim  the  use  of  all  varieties  of  cotton,  it  was  difficult  to 
see  on  what  ground  Thomas  and  Prevost  could  substantiate  their  claim 
for  a  patent.  Patents  covering  the  process  of  mercerising  appear  to  be 
without  foundation;  though  for  machinery  and  appliances  for  carrying 
out  the  same  such  patents  may  be  perfectly  legitimate.  Decisions  on  this 
matter  in  the  United  States  and  Germany  have  invalidated  Thomas  and 
Prevost's  patents. 

3.  Essentials  of  Mercerising. — Mercerising,  in  its  essential  meaning 
relates  to  the  action  of  certain  chemicals  on  cellulose,  whereby  the  latter 
is  changed  to  a  product  known  as  cellulose  hydrate,  though,  technically, 
the  term  has  come  to  mean  the  process  concerned  with  the  imparting  of 
a  silk-like  luster  to  the  fiber. ^  As  generally  understood,  it  consists 
briefly  in  impregnating  cotton  yarn  or  cloth  with  a  rather  concentrated 
cold  solution  of  caustic  soda  and  subsequently  washing  out  the  caustic 
liquor  with  water,  the  material  being  either  held  in  a  state  of  tension 
during  the  time  it  is  treated  with  the  caustic  alkali  in  order  to  prevent 
contraction,  or  stretched  back  to  its  original  length  after  treatment  with 
the  alkali,  but  previous  to  washing.     In  either  case,  the  material  must 

1  There  is  much  to  be  said  both  pro  and  con  as  to  whether  cellulose  hydrate  is  a 
definite  chemical  compound  containing  water  of  constitution,  and  whether  mercerised 
cotton  is  chemically  different  in  its  constitution  from  ordinary  cotton.  Wichelhous 
and  Vieweg  (Berichle,  1907,  pp.  441  and  3880)  show  that  there  is  considerable  difference 
in  the  alcohol-ether  solubility  of  the  nitrates  prepared  from  ordinary  and  mercerised 
cottons;  also  the  latter  gives  a  greater  yield  of  the  benzoic  acid  ester,  and  hence  it  is 
concluded  that  mercerised  cotton  is  a  hydrated  cellulose.  Schwalbo,  Cross  and  I^evan, 
and  Berl  are  also  of  the  same  opinion.  These  differences  in  reactions,  however,  are 
by  no  means  conclusive  evidences  of  differences  in  chemical  constitution,  for  the 
cellulose  of  cotton  is  a  complex  colloidal  body  and  its  reactivity  is  readily  affected 
by  physical  molecular  changes  which  need  not  indicate  definite  chemical  changes. 


ALKALI-CELLULOSE  581 

be  in  a  state  of  tension  during  the  process  of  washing.  There  are  two 
separate  phases  of  the  mercerising  process  represented  in  the  above 
operations  which  must  be  separately  understood  in  order  to  comprehend 
the  exact  natm'e  of  the  change  which  takes  place  in  the  appearance  of  the 
fiber;  the  one  is  the  chemical  action  of  the  caustic  soda,  and  the  other  is 
the  mechanical  effect  brought  about  by  the  tension.  The  action  of  the 
caustic  alkali  is  to  effect  a  chemical  transformation  in  the  substance  of  the 
fiber,  a  further  chemical  reaction  taking  place  when  this  product  is  treated 
with  water. 

Miller  ^  is  of  the  opinion  that  mercerised  cotton  does  not  represent  a 
cellulose  hj^drate.  If  the  material  is  dried  at  95°  C,  before  and  after 
mercerisation,  a  slight  loss  of  weight  is  recorded,  instead  of  a  gain,  as  a 
result  of  the  treatment.  The  hygroscopic  moisture  of  mercerised  cotton 
is  the  same  whether  the  sample  be  dried  at  95°  C.  in  an  oven  or  at  25°  C. 
over  calcium  chloride.  A  hydrate  stable  between  these  extremes  of  tem- 
perature is  hardly  conceivable.  Wlien  dried  in  vacuo  over  sulfuric  acid, 
mercerised  cotton  has  the  same  percentage  composition  as  cotton  itself. 
On  the  other  hand,  mercerised  cotton  behaves  differently  from  ordinary 
cotton  in  certain  chemical  reactions ;  it  also  shows  an  increased  adsorption 
capacity  for  atmospheric  moisture,  dyestuffs,  etc.  From  these  facts 
Miller  contends  that  in  the  process  of  mercerisation  the  sodium  hydroxide 
enters  into  a  state  of  solid  solution  in  the  cellulose  and  this  process  is 
accompanied  by  a  partial  conversion  of  the  cellulose  into  an  isomeride, 
the  extent  of  this  conversion  depending  on  the  concentration  of  the  alkali. 

4.  Alkali-cellulose. — As  previously  pointed  out  cellulose  has  the 
property  of  combining  with  caustic  soda  in  the  ratio  of  C12H20O10  :  NaOH 
to  form  a  product  known  as  alkali-cellulose,  Ci2H2oOio-NaOH.  The 
formation  of  this  compound  does  not  appear  to  disintegrate  the  organic 
structure  of  the  fiber-cell,  provided  the  proper  conditions  are  main- 
tained. The  alkali-cellulose,  however,  is  apparently  a  rather  feebly 
combined  molecular  aggregate,  and  does  not  exhibit  much  stability 
toward  reagents  in  general.  It  is  even  decomposed  by  the  action  of 
water,  the  effect  of  the  latter  being  to  disrupt  the  bond  of  molecular 
union  between  the  alkali  and  cellulose,  with  the  consequent  reforma- 
tion of  caustic  soda  and  the  introduction  of  water  into  the  cellulose  mole- 
cule. This  latter  substance,  which  may  be  termed  cellulose  hydrate, 
forms  the  chemical  basis  of  mercerised  cotton.  The  theory  that  caustic 
soda  effects  a  true  chemical  combination  with  cellulose  is  somewhat 
supported  by  the  fact  that  mercerised  cotton  undergoes  chemical  changes 
to  which  ordinary  cotton  is  not  susceptible.  For  instance,  the  former  is 
much  more  readily  dissolved  bj''  a  solution  of  ammoniacal  copper  oxide; 
it  is    chemically  reactive  with  carbon  disulfide  with    the    formation  of 

1  Berichte,  1910,  p.  3430. 


582 


MERCERISED  COTTON 


soluble  cellulose  thiocarbonates;  alkali-cellulose  also  reacts  with  benzoyl 
chloride  and  acetic  anhydride,  giving  rise  to  cellulose  benzoates  and 
acetates.  The  nature  of  the  chemical  change  in  mercerised  cotton, 
however,  is  rather  ill  defined ;  it  no  doubt  can  be  included  under  that  class 
of  reactions  which  stands  somewhat  midway  between  ordinary  physical 
and  chemical  changes,  and  is  to  be  particularly  observed  in  connection 
with  those  bodies  possessing  a  high  degree  of  molecular  complexity,  such 
as  various  colloidal  substances  and  the  large  number  of  naturally  occurring 
carbohydrates,  starches,  gums,  etc.     The  fact  that  there  is  no  evidence 


Fig.  217. — Centrifugal  Skein  Mercerising  Machine.     (Klein ewefer.) 


of  disorganisation  in  the  fiber  cell,  as  may  be  observed  from  its  physical 
properties  and  microscopic  appearance,  is  a  strong  argument  against  true 
chemical  change,  which  would  necessitate  a  rearrangement  in  the  atomic 
grouping  in  the  substance  of  the  fiber.  This  would  result  in  a  decompo- 
sition of  its  organised  structure,  which  would  at  once  be  manifested  in  a 
decrease  in  the  tensile  strength,  and  an  actual  breaking  down  of  the  fiber 
itself.  But  mercerised  cotton  shows  no  such  change;  on  the  other  hand, 
its  tensile  strength  is  consideralDly  increased,  and  the  fiber-cell  shows  no 
tendency  toward  physical  decomposition. 

According  to  Schwalbe  ^  the  absorption  curve  of  cotton  with  caustic 

1  Berichte,  1907,  p.  3876. 


ALKALI-CELLULOSE 


583 


soda  shows  two  distinct  points  corresponding  respectively  to  molecular 
ratios  of 


and 


C12H20O10  :  NaOH 
C12H20O10  :  2NaOH. 


Schwalbe  ascribes  to  alkali-cellulose  the  formula,  C]2Hi90ioNa,  claiming 
it  is  a  definite  chemical  compound  capable  of  combining  with  more  alkali 
until  eventually  the  compound  Ci2Hi90ioNa-NaOH  is  formed. 


Fig.  218. — Skein  Mercerising  Machine.     (Smith,  Drum  &  Co.) 

Alkali-cellulose  is  decomposed  on  exposure  to  the  air  by  reason  of  the 
moisture  and  carbon  dioxide  combining  with  the  alkali.  Alkali-cellulose 
freed  from  soda  by  washing  with  water,  that  is  to  say,  converted  into 
hydrocellulose,  has  a  greater  affinity  for  substantive  dyes  than  the  alkali- 
cellulose  washed  with  hot  absolute  alcohol.  In  the  latter  case  there  is  no 
hydration  of  the  cellulose.^ 

Washing  with  absolute  alcohol  (cold)  does  not  decompose  alkali- 
cellulose,  and  thus  allows  of  the  determination  of  the  quantity  of  soda 

1  Miller,  Benchte,  1910,  p.  3430. 


584 


MERCERISED   COTTON 


fixed  or  combined  with  cellulose  in  the  case  of  treatment  with  caustic 
soda  solutions  of  different  degrees  of  concentration.  Hot  alcohol,  how- 
ever, decomposes  alkali-cellulose. 

Vieweg  ^  has  studied  the  absorption  of  caustic  soda  by  cotton  in  the 
following  manner:  3  grams  of  pure  absorbent  cotton,  dried  at  212°  F. 
were  immersed  in  200  cc.  of  caustic  soda  solutions  of  different  degrees 
of  concentration.  After  two  hours  standing,  50  cc.  of  the  liquor  in  each 
test  was  taken  out  and  titrated  with  N/  10  sulfuric  acid,  using  phenolphtha- 
lein  as  an  indicator.     The  loss  in  strength  of  the  soda  solution  allowed  a 


Fig.  219. — Skein  Mercerising  Machine.     (R.  J.  Marx,  England.) 

calculation  to  be  made  as  to  the  amount  of  caustic  soda  combined  with  the 
cotton.     The  following  table  gives  the  results  obtained: 


Concentration  of  caustic  soda; 
grams  NaOH  per  100  cc.  water 

0.4 

2.0 

6.0 

8.0 

12 

16 

20 

24 

28 

33 

35 

40 

Caustic  soda  fixed;  grams  NaOH 
per  100  grams  cotton 

0.4 

0.9 

2.7 

4.4 

8.4 

12.6 

13 

13 

15.4 

20.4 

22.5 

22.5 

It  will  be  noted  that  there  are  two  points  where  the  absorption  becomes 
constant,  at  a  concentration  of  about  16  percent  NaOH,  and  again  at  35 

1  Berichie,  1907,  p.  3876. 


ALKALI-CELLULOSE 


585 


percent  NaOH.  The  absorption  in  each  case  would  apparently 
correspond  to  alkali-cellulose  compounds  of  (C6Hio05)2-NaOH,  and 
(CeHi 00.5)2  ■  2NaOH,  respectively. 

Htibner  and  Teltscher  ^  have  also  studied  this  question  in  a  somewhat 
different  manner:  10  grams  of  purified  cotton  were  immersed  in  600  cc. 
of  caustic  soda  solutions  of  different  concentrations  for  sixty-seven  hours. 
The  excess  of  caustic  soda  was  then  drained  off  and  the  samples  were 
washed  with  absolute  alcohol  (cold)  until  no  longer  showing  an  alkaline 
test  with  phenolphthalein.  The  amount  of  combined  caustic  soda  was 
then  determined  by  ignitions.^  The  results  are  shown  in  the  following 
table : 


Grams  of  NaOH  in 
100  cc.  of  Liquor. 

°Tw. 

NaOH  Retained  by 

100  Grams  Cotton, 

Grams. 

Times  Washed  with 
Absolute  Alcohol. 

0.4 

1 

0.190 

6 

2.3 

5 

0.198 

13 

4.19 

10 

0.330 

17 

8.68 

20 

0.710 

30 

9.98 

23 

1.456 

38 

11.47 

26 

2.752 

45 

13.39 

30 

3.250 

63 

15.47 

35 

3.298 

70 

17.67 

40 

3.600 

74 

20.03 

45 

3.184 

81 

22.42 

50 

2.722 

86 

27.10 

60 

2.824 

89 

31.74 

70 

3.030 

91 

36.54 

80 

3.024 

96 

With  regard  to  the  influence  of  salt  on  the  action  of  caustic  soda  on 
cotton  in  mercerising,  Vieweg  gives  the  following  figures  showing  the 
comparative  absorptions  at  20°  C. : 


^Jour.  Soc.  Chem.  Ind.,  1909,  p.  641. 

^  The  work  of  Hiibner  and  Teltscher  and  also  that  of  Miller  {Chem.  Zeit.,  1905, 
p.  491)  seems  to  disprove  m  large  degree  the  earlier  work  of  Vieweg  and  that  of  Glad- 
stone in  not  establishing  any  positive  evidence  of  the  existence  of  a  definite  compound 
of  cellulose  with  caustic  soda.  According  to  the  investigations  of  Ost  and  Westoff 
(Chem.  Zeit.,  1909,  p.  198)  both  mercerised  cellulose  and  the  regenerated  cellulose 
from  fresh  viscose,  when  freed  from  all  hygroscopic  water  at  120°  to  125°  C.  show 
the  same  formula  as  ordinary  cellulose  (C6Hio05)n.  This  would  seem  to  argue  agamst 
the  view  that  there  is  a  definite  chemical  compound  between  cellulose  and  caustic 
soda  or  that  mercerised  cotton  represents  a  hydrated  cellulose  in  which  water  is  present 
as  constitutional  water  of  hydration. 


,586 


MERCERISED   COTTON 


Strength 

of  the  Lye, 

Percent. 

Percentage  of  NaOH  Absorbed. 

From  Pure  Lye. 

From  Lye  Saturated 
with  Common  Salt. 

2 
4 
8 
12 
16 
20 
24 

0.9 

2.7 

4.4 

8.4 

11.3 

13.2 

12.8 

3.8 
6.4 
14.5 
17.1 
17.4 
18.5 

Harrison  points  out  that  the  action  of  caustic  soda  on  cotton  has  been 
variously  interpreted  by  different  investigators  as  follows: 

Mercer  (1850) (C6Hio06)2Na20 

Thiele Ci2H2oOi22NaOH 

Beilstem  (3rd  Ed.,  I.,  1074) 2C6Hio05NaOH 

Cross  (from  "Viscose") C6Hio052NaOH 

Gladstone  {Jo\ir.  Chem.  Soc,  17,  1862) C,2H2oOioNaOH 

Crum  (Jour.  Chem.  Soc,  16,  406) Ci2H2oO,o2NaOH 

Cross  and  Bevan  (Cellulose,  p.  23) Ci2H2tiOio2NaOH 

Mercer  and  Gladstone  deduced  their  formulae  from  the  amount  of 
NaOH  retained  after  treatment  of  cotton  with  caustic  soda  and  washing 
with  alcohol.  Htibner  and  Teltscher  carried  out  numerous  experiments 
similar  to  those  of  Mercer  and  of  Gladstone,  but  found  no  evidence  of  the 
formation  of  a  definite  compound  of  cellulose  and  caustic  soda.  Vieweg, 
in  determining  the  amount  of  caustic  soda  absorbed  by  cotton  at  different 
concentrations,  found  two  points  at  16  percent  and  40  percent  NaOH, 
corresponding  to  the  formation  of  two  compounds,  (C(jHio05)2NaOH  and 
(CoHio05)22NaOH.  Miller  states  that  no  compounds  are  formed  between 
cellulose  and  caustic  soda,  and  considers  that  the  results  of  Vieweg  repre- 
sent a  solution  phenomenon.  Harrison  himself  thinks  it  is  highly  probable 
that  in  the  reaction  between  cotton  and  caustic  soda,  adsorption  compounds 
are  formed  in  a  similar  manner  to  that  observed  with  many  other  colloidal 
substances,  but  as  changes  in  the  physical  state  of  the  fiber  are  produced 
by  certain  concentrations  of  soda,  the  ordinary  adsorption  formula  will 
not  be  followed. 

5.  Physical  Changes  in  Cotton  Fiber  by  Mercerising. — When  the 
cotton  fiber  is  immersed  in  a  concentrated  solution  of  caustic  soda  it  under- 
goes a  peculiar  physical  modification;  it  appears  to  absorb  the  alkali, 
swelling  to  a  cylindrical  form,  so  that  it  presents  more  the  appearance  of 
a  hair  than  a  flat  ribbon ;  the  fiber  also  untwists  itself  and  becomes  much 


PHYSICAL  CHANGES  IN  COTTON  FIBER  BY  MERCERISING     587 


588 


MERCERISED   COTTON 


straighter,  at  the  same  time  shrinking  considerably  in  length.  The  internal 
portion  of  the  fiber  acquires  a  gelatinous  appearance,  becoming  somewhat 
translucent  to  light,  though  it  is  firm  in  structure ;  the  surface  of  the  fiber 
shows  a  wrinkled  appearance  transversely,  due  to  a  somewhat  unequal 
distension  of  the  inner  part.  There  is  a  small  degree  of  luster  on  portions 
of  the  surface,  but,  due  to  the  uneven  stretching  and  wrinkling  of  the 
external  superficies,  the  smooth  lustrous  portions  are  irregular  in  occurrence 
and  not  very  extensive  in  area.  The  fiber  also  shows  a  slight  increase  in 
weight. 

The  physical  changes  in  the  appearance  of  the  cotton  fiber  when 
mercerised  have  been  studied  by  Hiibner  and  Pope  ^  as  follows : 

Strength  of  Soda  Solution.  Effect. 

To  15°  Tw No  apparent  change 

"   16°  to  18° SHght  but  incomplete  twisting 

' '  20° Initial  untwisting  followed  by  slow  vuicoiling  of  the  twist 

' '  26° Rapid  and  slow  uncoiling  become  one,  lasting  5  seconds 

' '  40° Untwisting  and  uncoiling  take  place  together 

"   60°  to  80° Swelling  precedes  untwisting 

6.  Changes  in  Properties. — The  changes  in  the  physical  appearance  of 

the  fiber  are  accom- 
panied by  a  remark- 
able increase  in  the 
tensile  strength, 
amounting  in  most 
cases  to  as  much  as 
from  30  to  50  per- 
cent; the  fiber  also 
acquiring  a  greater 
power  of  absorption 
toward  many  solu- 
tions, most  notably 
those  of  dyestuffs. 
The  increase  in  ten- 
sile strength  is  prob- 
ably due  to  the  fact 
that  mercerising 
causes  the  inner 
structure  of  the  fiber 
to  become  more  sol- 
idly bound  together 
by  a  filling  up  of  the 
interstitial  spaces  between  the  molecular  components  of  the  cell- wall.     In 


Fig.  221.— Mercerised  Cotton.     (X3.50.) 
author.) 


(Micrograph  by 


1  Jour.  Sac.  Chcm.  Ind.,  1904,  p.  404. 


CHANGES  IN  PROPERTIES  589 

this  manner  the  fiber  as  a  whole  is  given  a  greater  degree  of  soHdity ;  the  in- 
ternal strain  between  the  cell-elements  (which  must  be  quite  considerable 
after  the  drying  out  and  shrinking  of  the  ripened  fiber)  is  lessened  no  doubt, 
and  hence  adds  to  the  unified  strength  of  the  fiber.  From  the  fact  that  the 
fiber  shrinks  in  length  in  mercerising,  it  is  probable  that  the  cell-elements 
have  contracted  transversely  on  the  collapse  of  the  fiber  canal,  and,  on  being 
distended  again  by  the  action  of  the  caustic  alkali,  these  cell-elements 
become  shortened  longitudinally  and  are  more  tightly  packed  together. 


Fig.  222. — Typical  Structure  of  Mercerised  Cotton.     (Herzog.) 

Grosheintz  gives  the  following  results  of  some  experiments  on  the  effect 
of  mercerisation  on  the  tensile  strength  of  cotton:  Unmercerised  yarn 
broke  with  a  load  of  356-360  grams ;  same  yarn  mercerised  in  cold  aqueous 
caustic  soda  (35°  Be.)  broke  with  530-570  grams;  same  yarn  mercerised 
with  cold  alcoholic  caustic  soda  (10  percent)  broke  with  600-645  grams; 
same  (except  that  hot  alcoholic  caustic  soda  was  used)  broke  with  a  load 
of  690-740  grams. 

According  to  Bowman  ^  the  increase  in  strength  of  single  cotton  yarns 
(20  1  to  60/1)  by  mercerisation  is  about  32  percent  and  for  twofold  yarns 
50  percent.  The  yarns  were  mercerised  without  tension  in  cold  caustic  soda 
solution  of  1.35  sp.  gr.,  but  rinsed  under  tension. 

^  Structure  of  Cotton  Fiber,  p.  227. 


590  MERCERISED   COTTON 

The  increased  affinity  for  dyestuffs  exhibited  by  mercerised  cotton  is 
not  to  be  considered  a  new  inherent  property  of  the  modified  cellulose 
induced  by  a  change  in  its  chemical  composition.  It  is  no  doubt  a  result 
of  the  modified  physical  structure  of  the  fiber  itself;  that  is,  when  the 
cell-elements  have  become  distended,  like  a  sponge,  they  have  a  greater 
power  of  absorption  and  retention  of  liquids  than  when  in  a  flattened  and 
collapsed  condition. 

7.  Luster  of  Mercerised  Cotton. — The  high  luster  imparted  to  cotton 
by  mercerising  is  brought  about  by  other  conditions  than  the  mere  action 
of  the  caustic  alkali.  It  has  been  claimed  that  the  mercerising  effect 
may  be  obtained  without  tension  bj^  the  addition  of  glucose  to  the  alkaline 
bath.  The  addition  of  other  substances,  such  as  ether,  aluminium  chloride, 
etc.,  have  been  claimed  to  produce  the  same  result.  But  it  is  to  be  doubted 
whether  a  high  luster  is  obtained  by  any  of  these  methods. 

In  the  swelling  of  the  cell-walls  and  consequent  contraction  of  the 
fiber,  the  surface  remains  wrinkled  and  uneven,  due  to  the  unequal  strain 
of  expansion.  If,  however,  the  ends  of  the  fiber  are  fixed,  and  thus  pre- 
vented from  contracting  when  subjected  to  the  chemical  action  of  the 
alkali,  the  swelling  of  the  cell-walls  will  cause  the  surface  to  become 
smooth  and  even,  and  similar  to  a  polished  surface  capable  of  reflecting 
light  with  but  little  scattering  of  the  rays.  Hiibner  and  Pope  ^  have  ob- 
served that  in  mercerising  cotton  the  ribbon-like  fiber  becomes  untwisted, 
and  consider  that  this  change  of  twist  is  of  great  importance  in  the  pro- 
duction of  the  luster.  They  further  point  out  that  up  to  a  concentration 
of  40°  Tw.  the  swelling  action  of  the  caustic  lye  follows  the  untwisting; 
while  at  concentrations  above  40°  Tw.  the  untwisting  follows  the  swelling. 
As  40°  Tw.  is  the  lowest  concentration  at  which  effective  mercerisation  is 
brought  about,  it  is  considered  that  the  production  of  a  luster  on  cotton  is 
necessarily  connected  with  that  action  of  the  caustic  soda,  causing  an 
untwisting  of  the  fiber  to  take  place.  Another  condition  which  also  has 
much  to  do  with  the  production  of  the  lustrous  appearance  is  no  doubt  to 
be  found  in  the  physical  modification  of  the  cell  elements  themselves. 
When  the  fiber  swells  up  under  the  action  of  the  caustic  alkali,  its  sub- 
stance becomes  gelatinous  and  translucent,  and  this  has  a  marked  effect 
on  the  optical  properties  of  the  fiber  and  enhances  the  luster  considerably 
by  lessening  the  proportion  of  light  absorbed. 

Dr.  Frankel  has  advanced  the  opinion  that  the  high  luster  exhibited  by 
mercerised  cotton  is  mainly  due  to  the  fiber  having  lost  its  thin  cuticle 
during  the  process.  But  this  theory  is  overthrown  by  the  fact  that  if 
mercerised  cotton  is  again  subjected  to  the  action  of  cold  strong  caustic 
soda,  it  contracts  nearly  as  much  as  raw  cotton  would  do,  and  loses  its 
silky  luster  entirely.     According  to  Minajeff  -  the  cuticle  is  still  present  in 

1  Jour.  Soc.  Chcrn.  I  ml,  1904,  p.  404.         ^  Zeit.  Fdrben-IncL,  1908,  pp.  1  and  17. 


LUSTER  OF  MERCERISED  COTTON 


591 


both  mercerised  and  bleached  cotton.  The  cuticle  contains  as  incrusting 
bodies,  fat,  wax,  coloring  matter,  and  a  substance  called  cutin,  which  is 
insoluble  in  sulfuric  acid.  Processes  in  which  alkaline  agents  are  used, 
such  as  mercerising,  boiling-out,  and  bleaching,  will  remove  the  waxy 
and  fatty  bodies,  but  not  the  cuticle  itself.  In  some  cases  it  is  difficult 
to  distinguish  the  cuticle  under  the  microscope.  Minajeff  in  studying  the 
action  of  some  reagents  on  the  cotton  fiber  under  the  microscope  arrived 
at  the  following  conclusions:  The  cuticle  of  the  raw  cotton  fiber  resists 
treatment  with  concentrated  cuprammonium  solution,  fairly  strong 
sulfuric  acid  (but  not  the  concentrated  acid),  and  con- 
centrated alkaline  liquors  both  during  boiling  and  merceri- 
sation.  The  cuticle  of  the  bleached  fiber  has  the  same 
properties  as  those  of  the  unbleached,  though  not  to  the 
same  extent. 


Fig.  223. — Diagram  of  Automatic  Skein  Mercerising  Machine.     (Hahn  System.) 


Hiibner  and  Pope  ^  have  attributed  the  luster  of  mercerised  cotton 
to  the  reflection  of  light  from  the  spiral  ridges  on  the  surface  of  the  fiber 
caused  by  the  original  twists  in  the  fiber.  The  present  author  and  also 
Lange  ^  have  maintained  that  the  luster  is  simply  due  to  the  stretching 
of  the  surface  by  distension,  thus  producing  a  smooth  surface  which  more 
readily  reflects  light.  Harrison  ^  also  comes  to  this  same  conclusion 
after  an  exhaustive  examination  of  the  fiber  by  microscopic  methods. 
If,  as  Hiibner  and  Pope  assert,  the  only  difference  between  cotton  mer- 

1  Jour.  Sac.  Chew.  I  ml,   1904,  p.  410. 

2  Farber-ZeU.,   1S9S,  p.  197. 

3  Jour.  Soc.  Dyers  &  Col,  1915,  p.  202. 


592 


MERCERISED   COTTON 


cerised  loose  and  under  tension  lies  in  the  absence  of  corkscrew-like  grooves 
in  the  former,  then  it  follows  that  if  such  grooves  could  be  obtained  in 
cotton  mercerised  loose  it  should  possess  luster.  If  one  stretches  a  number 
of  separated  fibers  between  two  holders  and  then  mercerises  them,  and 
allows  them  to  shrink  only  so  far  that  the  fibers  remain  straight  but  not 
under  tension,  then  washes  and  dries  the  fibers  in  the  holder,  they  will 
be  found  to  possess  little  or  no  luster;  l^ut  if  one  remercerises  these  same 
fibers  without  having  removed  them  from  the  holder,  and  stretches  them 
to  their  original  length  before  washing,  they  will  be  found  to  be  lustrous. 


Fig.  224. — Automatic  Skein  Mercerising  Machine.     (Haubold  System.) 


Obviously,  the  number  of  twists  per  fiber  will  be  the  same  in  each  case, 
and  the  number  of  twists  per  inch  will  be  greater  with  the  fibers  mercerised 
without  tension,  so  that  these  results  are  not  in  agreement  with  Hiibner 
and  Pope's  theory. 

Harrison  is  of  the  opinion  that  the  shrinkage  of  the  cotton  fiber  during 
mercerising  is  due  to  strains  within  the  fiber  which  become  active  when 
the  fiber  is  softened  by  the  caustic  soda. 

In  order  to  explain  how  this  conclusion  has  been  obtained,  Harrison 
refers  to  experiments  on  starch.  It  was  shown  that  the  characteristic 
appearance  of  starch  grains  under  polarised  light  is  due  to  strains  within 


EFFECT  OF   TENSION  593 

the  grains,  since  the  same  appearance  was  produced  in  drops  of  gelatine 
by  the  strains  set  up  on  allowing  the  drops  to  dry,  and  further  since  the 
removal  of  the  strains  from  starch  by  the  solvent  action  of  hot  water 
removed  the  property  of  acting  on  polarised  light.  A  similar  result  has 
been  obtained  with  cotton.  Under  polarised  light  between  crossed  Nicols 
cotton  fibers  show  strong  illumination.  When  the  fibers  are  treated 
with  Schweitzer's  reagent  this  effect  disappears.  Illumination  persists 
only  in  the  parts  not  completely  swollen,  which  form  the  rings  of  the 
barrel-shaped  formations  well  known  to  be  formed  with  unmercerised 
cotton.  Artificial  silk  made  from  cuprammonium  solution  also  shows  the 
illumination  between  crossed  Nicols,  and  this  is  also  removed  when  the 
fibers  are  treated  with  Schweitzer's  reagent.  A  rod  having  strain  lines 
running  parallel  to  its  axis  when  placed  between  crossed  Nicols  and  turned 
round  at  right  angles  to  its  axis  in  a  plane  perpendicular  to  the  incident 
light,  would  appear  dark  when  parallel  or  at  right  angles  to  the  plane  of 
polarisation,  and  brightest  when  at  45°  to  the  plane  of  polarisation.  A 
good  example  of  this  is  afforded  by  a  strand  of  unvulcanised  India  rubber 
stretched  when  warm  and  fixed  by  cooling.  Cotton  fibers  have  been 
found  to  behave  like  such  strained  rods.  The  untwisting  of  fibers  on 
mercerisation  is  most  probably  due  to  the  strains  being  distributed  par- 
tially in  spiral  form.  The  examination  of  fibers  in  polarised  light  affords 
a  means  of  distinguishing  between  mercerised  and  unmercerised  cotton. 
The  corrugated  strain  lines,  distinct  in  unmercerised  cotton,  are  diffused  in 
cotton  mercerised  without  tension,  and  entirely  missing  in  cotton  mer- 
cerised under  tension.  The  difference  in  appearance  when  examined  at 
different  angles  to  the  plane  of  polarisation  also  serves  for  distinguishing 
them.  The  difference  in  the  appearance  of  the  transverse  sections  is  very 
considerable. 

8.  Effect  of  Tension. — Considerable  difference  is  to  be  observed  in  the 
strength  and  elasticity  of  cotton  mercerised  without  tension  and  that 
mercerised  with  tension.  Buntrock,  in  a  research  on  this  subject,  found 
that  cotton  yarn  mercerised  without  tension  showed  an  increase  of  68  per- 
cent in  its  tensile  strength,  whereas  the  same  cotton  mercerised  under 
tension  gave  an  increase  of  only  35  percent.  With  respect  to  the  elasticity 
of  the  yarn,  the  same  chemist  ascertained  that  the  untreated  cotton 
employed  in  his  experiments  stretched  11  percent  of  its  length  before 
breaking;  the  amount  for  cotton  mercerised  without  tension  was  17 
percent,  an  increase  of  54  percent ;  cotton  mercerised  under  tension  showed 
no  increase  in  elasticity  at  all,  and  could  only  be  stretched  the  original 
11  percent  before  breaking.  These  figures,  of  course,  are  not  absolute 
for  all  varieties  of  cotton,  but  will  vary  within  considerable  limits,  depend- 
ing upon  the  character  of  the  raw  cotton  employed.  Attention  must  also 
be  drawn  to  the  fact  that  the  figures  for  the  tensile  strength  and  elasticity 


594 


MERCERISED   COTTON 


quoted  above  were  obtained  by  using  spun  yarn  and  are  not  based  on  the 
single  fiber.  Of  course  it  is  the  strength  of  the  yarn  which  is  desired  in 
practice,  but  the  figure  for  this  is  not  necessarily  that  for  the  fiber  itself. 
In  mercerising  yarn  or  cloth,  it  must  be  borne  in  mind  that  the  fibers 
shrink  considerably,  and  in  doing  so  become  more  closely  knit  together; 
therefore  the  increase  in  tensile  strength,  as  ascertained  by  Buntrock, 
represents  really  the  greater  coherence  of  the  fibers  to  one  another  rather 
than  an  increase  in  the  strength  of  the  individual  fiber,  because  in  breaking 
a  yarn  spun  from  a  large  number  of  fibers  there  is  little  or  no  actual  breaking 
of  the  fibers  themselves,  but  only  a  pulling  apart  of  the  latter.  The 
same  criticism  also  applies  to  a  determination  of  the  elasticity.  It  would, 
perhaps,  be  more  scientific  to  determine  the  breaking  strain  and  elasticity 
of  the  separate  fibers  rather  than  that  of  the  yarn  or  cloth;  but  it  may  be 
assumed,  with  considerable  show  of  reason,  that  these  figures  of  Buntrock 
will  represent  a  fair  relation  between  the  strength  and  elasticity  of  the 
individual  fibers.  The  cause  of  the  lesser  increase  in  tensile  strength  of 
cotton  mercerised  under  tension  as  compared  with  that  of  the  same  cotton 
mercerised  without  tension  is  to  be  attributed  to  the  fact  that  when  the 
shrinkage  of  the  fiber  is  prevented  by  the  application  of  an  external  force 
the  cell  tissues  cannot  become  as  compact  as  otherwise,  and  there  is  also  an 
internal  strain  induced  which  lessens  the  ultimate  strength  of  the  fiber. 
This  latter  condition  also  accounts  for  the  lack  of  any  increase  in  the 
elasticity  of  the  mercerised  fiber;  the  fiber  when  mercerised  under  tension 
is  already  in  a  stretched  or  strained  condition,  and  can  hardly  be  expected 
to  give  the  same  degree  of  elasticity  as  if  tension  had  not  been  applied,  as  a 
certain  part  of  its  elasticity  has  been  used  up  by  the  stretching. 

9.  Effect  of  Mercerising  on  Physical  Properties  of  Yams. — In  a  study 
made  by  R.  S.  Thoms  ^  on  the  effect  of  mercerising  and  bleaching  on  cotton 
yarns  the  following  results  were  obtained : 


Loss  in  weight,  percent 

Loss  in  length,  percent 

Mean  count 

Lea  break,  in  pounds 

Double  thread  break,  in  ounces. . 
Double  thread  stretch,  in  ^  inch. 

Mean  turns  per  inch 

Moisture,  percent  as  regain 


Gray. 


0 

0 

16.46 
97.0 
27.68 
20.57 
20.18 

5.86 


Boiled. 


5.53 
1.95 
17.66 
72.41 
23.26 
14.22 
19.88 
5.07 


Mercerised. 


4.61 
1.00 
17.42 
82 .  19 
26.12 
11.08 
19.57 
7.18 


^Jour.  Soc.  Dyers  &  Col,  1911,  p.  178 


Mercerised 
and 

Bleached, 
Chloride 
of  Lime. 


3.02 
0.37 
17.35 
86.41 
27.55 
10.25 
19.99 
7.34 


THEORY  OF   MERCERISING   ACTION 


595 


Mercerised 

and 
Bleached, 
Sodium 
Hypo- 
chlorite. 


Mercerised 

and 

Bleached, 

Electrolytic 

Bleach. 


Bleached, 

Chloride 

of 

Lime. 


Bleached, 
Sodium 
Hypo- 
chlorite. 


Loss  in  weight,  percent 

Loss  in  length,  percent 

Mean  count 

Lea  break,  in  pounds 

Double  thread  break,  in  ounces.. 
Double  thread  stretch,  in  xs  iiich 

Mean  turns  per  inch 

Moisture,  percent  as  regain 


3.03 
1.11 
17.02 
87.12 
28.08 
11.09 
20.20 
7.55 


3.06 
1.14 
17.02 
85.94 
27.58 
10.78 
20.25 
7.59 


5.00 
2.04 
17.35 
17.66 
24.14 
13.76 
20.07 
5.28 


4.91 
1.73 
17.45 
79.97 
23.93 
13.97 
20.11 
5.46 


Bleached, 

Electrolytic 

Bleach. 

Bleached, 
Chloride  of 

Lime  and 
Mercerised. 

Bleached, 

Sodium 

Hypochlorite 

and 
Mercerised. 

Bleached, 

Electrolytic 

Bleach 

and 

Mercerised. 

Loss  in  weight,  percent 

Loss  in  length,  percent 

4.88 
1.97 
17.40 
79.78 
23.65 
13.78 
19.89 
5.42 

3.40 

0.17 
17.58 
80.28 
26.52 

9.08 
19.91 

7.63 

3.37 

0.63 
17.24 
80.47 
26.14 

9.23 
19.32 

7.69 

3.37 

0.10  gain 

17  40 

Mean  count 

Lea  break,  in  pounds 

Double  thread  break,  in  ounces. .  . 
Double  thread  stretch,  in  ^  inch. . 

Mean  turns  per  inch 

Moisture,  percent  as  regain 

78.28 
25.85 

8.90 
19.59 

8.19 

10.  Theory  of  Mercerising  Action. — The  reaction  between  cotton  and 
caustic  soda  in  the  mercerising  process  is  generally  considered  as  a  chemical 
one.  This  was  the  opinion  of  Mercer  himself,  and  was  supported  by 
Gladstone,  Cross  and  Bevan,  Beltzer  and  many  other  prominent  chemists. 
Recently,  however,  Ristenpart  has  advanced  the  idea  that  the  process 
of  mercerisation  is  principally  an  osmotic  action,  and  the  contraction  which 
the  cotton  undergoes  when  mercerisation  i%  unaccompanied  bj^  tension 
is  due  to  purely  physical  causes.  The  cotton  fiber  is  surrounded  by  a 
hardened  cuticle,  and  this  acts  as  a  dialysing  membrane  to  induce  osmotic 
action;  when  the  fiber  is  steeped  in  a  strong  solution  of  caustic  soda  the 
water  tends  to  diffuse  faster  from  the  fiber  into  the  surrounding  liquid, 
while  the  soda  tends  to  diffuse  faster  into  the  fiber.  This  osmotic  condi- 
tion demands  an  increased  pressure  within  the  fiber  causing  it  to  swell. 
In  doing  this  it  will  naturally  assume  a  form  which  will  give  it  the  greatest 


596 


MERCERISED  COTTON 


internal  capacity  for  a  minimum  surface,  hence  the  fiber  contracts  in 
length  and  tends  to  assume  a  straight  cyHndrical  form. 

Later  experiments  on  the  action  of  caustic  soda  solutions  on  cotton 
seem  to  disprove  the  opinion  that  there  is  any  chemical  action  between 
the  fiber  and  the  caustic  soda.  Harrison  ^  states  that  the  compounds 
formed  in  the  reaction  between  cotton  and  caustic  soda  are  most  probably 
adsorption   compounds.     The   experiments   of   Hiibner   and   Teltscher  - 


Fig.  225. — Automatic  Skein  Mercerising  Machine,  Swiss  Type.     (Bolder  System.) 


also  indicate  that  there  is  no  evidence  of  the  formation  of  definite  com- 
pounds of  cellulose  and  caustic  soda. 

11.  Conditions  of  Mercerising;  Chemicals  Employed. — The  proper 
conditions  for  carrying  into  practical  operation  the  mercerising  process 
are  simple  and  easily  realised.  Caustic  soda  is  the  most  suitable  and 
convenient  reagent  for  bringing  about  the  hydration  of  the  cellulose; 
and  it  has  been  found  that  a  solution  of  density  between  60°  and  70°  Tw. 
gives  the  best  results.     Solutions  of  caustic  potash  probably  give  a  some- 

1  Jour.  Soc.  Dyers  &  Col.,  1915,  p.  202. 
Vow.  -Soc  Chem.  Ind.,  1909,  p.  641. 


CONDITIONS  OF   MERCERISING;     CHEMICALS   EMPLOYED     597 

what  better  luster,  and  the  shrinkage  of  the  fiber  is  less  than  with  caustic 
soda.  But  these  small  advantages  are  not  sufficient  to  compensate  for 
the  extra  expense  which  would  be  entailed  by  the  use  of  caustic  potash. 

Caustic  soda  solutions  of  less  density  than  15°  Tw.  have  but  little 
action  on  cotton;  the  maximum  effect  appears  to  be  produced  by  a  con- 
centration of  about  60°  Tw.,  though  the  difference  between  this  and  that 
obtained  at  50°  Tw.  is  not  very  marked,  and  even  at  40°  Tw.  the  mercer- 
ising action  of  the  alkali  is  quite  strong. 

Vieweg  ^  found  that  cotton  absorbed  caustic  soda  from  a  16  percent 
solution  (36°  Tw.)  to  form  a  compound  of  the  formula,  Ci2H2oOio-NaOH, 
while  from  solutions  containing  35  percent  (76°  Tw.)  of  caustic  soda  the 
cellulose  compound  corresponded  to  the  formula  Ci2H2oOio-2NaOH. 
Hiibner  and  Teltscher,^  however,  find  that  the  maximum  absorption  of 
caustic  soda  not  subsequently  removed  by  washing  with  absolute  alcohol, 
occurs  at  a  strength  of  40°  Tw.,  while  less  alkali  is  taken  up  from  stronger 
solutions;  and  contrary  to  the  opinion  of  Gladstone  and  Vieweg,  they 
find  no  evidence  inferring  the  existence  of  soda  celluloses  as  distinct 
chemical  compounds. 

Other  reagents  than  caustic  alkalies,  however,  may  be  employed  for  the 
hydrol3"sis  of  the  cotton.  Concentrated  mineral  acids,  such,  for  instance, 
as  sulfuric  acid  at  a  density  of  100°  to  125°  Tw.,  will  bring  about  the 
mercerising  effect  more  or  less  perfectly;  the  same  is  also  true  of  certain 
metallic  salts,  most  notably  the  chlorides  of  zinc,  calcium,  and  tin. 
Beyond  a  mere  theoretical  and  chemical  interest,  however,  mercerising 
by  means  of  such  reagents  has  no  practical  value.  Mercer  is  his  original 
patent  describes  the  use  of  concentrated  sulfuric  acid,  zinc  chloride,  and 
phosphoric  acid  as  mercerising  agents.  Hiibner  and  Pope  ^  find  that 
cotton  yarn  steeped  in  sulfuric  acid  of  114°  Tw.  shows  a  contraction  of 
9.5  percent.  When  immersed  in  the  stretched  condition  a  perceptible 
luster  is  obtained.  A  50  percent  solution  of  zinc  chloride  caused  a  con- 
traction of  2.3  percent,  and  where  acting  on  the  stretched  yarn  gave  a 
slight  luster.  Nitric  acid  of  83°  Tw.  caused  a  contraction  of  9.5  percent, 
and  when  treated  under  tension  the  yarn  showed  some  luster.  Concen- 
trated hydrochloric  acid  caused  a  contraction  of  1.8  percent,  and  a  slight 
degree  of  luster  was  developed  under  tension,  A  30  percent  solution  of 
sodium  sulfide  caused  a  contraction  of  1.3  percent  and  a  slight  degree  of 
luster  could  be  developed  by  stretching.  In  none  of  these  cases,  however, 
was  the  mercerising  effect  at  all  comparable  to  that  obtained  by  the 
ordinary  process  with  caustic  soda. 

Hiibner  and  Pope  '*  have  shown  that  the  mercerising  effect  may  be 
produced  with  strong  solutions  of  potassium  iodide,  the  fiber  retaining 

1  Berichte,  1907,  p.  3876.  '  Jour.  Soc.  Chem.  Ind.,  1904,  p.  409. 

2  Jour.  Soc.  Chem.  Ind.,  1909,  p.  643.  *  Jour.  Soc.  Chem.  Ind.,  1904,  p.  404. 


598 


MERCERISED   COTTON 


CONDITIONS   OF   MERCERISING;    CHEMICALS   EMPLOYED      599 

15  percent  of  the  salt  and  showing  an  increased  affinity  for  many 
dyes. 

The  use  of  sulfide  of  sodium  or  potassium  instead  of  caustic  alkali  has 
been  proposed;  but  the  process  yields  very  poor  results.  It  is  claimed  that 
by  adding  ether  to  the  caustic  soda  solution  good  mercerisation  can  be 
obtained  with  but  little  contraction  of  the  fiber,  but  as  this  process  requires 
fifty  parts  of  ether  to  twenty  parts  of  caustic  soda  solution,  the  expense 
renders  it  ridiculously  impracticable.  It  is  said  that  the  addition  of  car- 
bon bisulfide  to  the  bath  of  caustic  soda  very  materially  increases  the 
luster,  this  causes  a  disintegration  of  the  fiber,  however,  through  the 
formation  of  viscose;  hence  the  treatment  should  be  very  bi'ief,  otherwise 
the  cotton  will  be  seriously  tendered.  The  mercerised  fiber  is  first  as 
stiff  as  horse-hair,  but  this  effect  can  be  removed  by  repeated  washing. 
The  sulfur  can  be  removed  from  the  cotton  by  washing  in  a  solution  of 
sal-ammoniac,  and  this  should  be  done  before  the  material  is  treated 
with  an  acid  bath,  as  the  latter  would  cause  a  precipitation  of  sulfur  on 
the  fiber  and  so  spoil  the  luster. 

The  addition  of  various  chemicals  has  been  made  to  the  caustic 
alkali  solution  with  beneficial  results  in  mercerising.  It  has  been  observed, 
for  instance,  that  the  addition  of  zinc  oxide  has  a  very  marked  effect. 
The  addition  of  glycerol,  though  perhaps  of  some  benefit  in  assisting  in 
the  even  and  thorough  penetration  of  the  liquor  into  the  fiber,  can  hardly 
be  said  to  appreciably  modify  the  general  operation  of  the  alkali.  Previ- 
ous treatment  with  Turkey-red  oil  is  also  of  benefit  for  the  same  reason; 
this  is  also  true  of  such  substances  as  sodium  aluminate,  and  soap.  The 
addition  of  sodium  silicate  or  glycerol  to  the  mercerising  lye  has  been 
found  to  retard  the  swelling  and  shrinkage  of  the  fibers,  and  therefore  the 
luster  obtained  is  inferior.^ 

A  solution  of  caustic  soda  of  13°  Be.  has  but  a  slight  mercerising  effect, 
but  by  the  addition  of  1  part  of  zinc  hydrate  (Zn(0H)2)  to  4  parts  of 
caustic  soda  (NaOH),  the  mercerising  effect  is  greatly  increased.  The 
addition  of  ammoniacal  hydrates  of  copper  and  nickel  also  have  the 
same  effect. 

Vieweg  ^  asserts  that  the  addition  of  sodium  chloride  materially  increases 
the  absorption  of  caustic  soda  by  cotton  in  mercerising.  Miller,^  however, 
states  that  the  absorption  of  caustic  soda  by  cellulose  is  not  influenced 
by  the  presence  of  either  sodium  chloride  or  sodium  carbonate.  Hiibner  ^ 
shows  that  the  presence  of  sodium  chloride  materially  reduces  the  mer- 
cerising effect   (shrinkage  and  luster)   of  caustic  soda  solution.     When 

1  See  Hiibner  and  Pope,  Jour.  Soc.  Chem.  Ind.,  1904,  p.  409. 

^  Berichle,  1908,  p.  3269. 

^  Jour.  Russ.  Chem.  Phys.  Gesell.,  1905,  p.  361 

*  Jour.  Soc.  Chem.  Ind.,  1909,  p.  228. 


600 


MERCERISED  COTTON 


examined  under  the  microscope  the  untwisting  of  the  fibers  is  also  slower 
and  less  complete.  Knecht  ^  has  also  carefully  tested  the  effect  of  mer- 
cerising with  and  without  the  addition  of  salt,  and  his  results  show  that 
the  contraction  of  the  fiber  and  the  affinity  for  dyestuffs  is  lessened  by  the 


Fig.  227. — Automatic    Skein    Mercerising    Machine;     Horizontal    Revolving    Type. 

(Spencer.) 

addition  of  salt.     He  gives  the  following  table  showing  the  quantitative 
absorption  of  several  dyestuffs: 


Dyestuff. 

Untreated  Cotton. 
Percent. 

Mercerised  with 

Caustic  Soda  Alone, 

Percent. 

Mercerised  with 

Caustic  Soda  and 

Salt,  Percent. 

Diamine  Sky  Blue 

Chrysophenine 

Benzopurpurine  4B .  .  .  . 

1.06 
0.74 
1  02 

1.66 
1   17 
1.97 

1  25 
1.01 
1.67 

'  Jour.  Soc.  Chem.  Ind.,  1909,  p.  228. 


CONDITIONS  OF   MERCERISING;    CHEMICALS  EMPLOYED      601 


35 


2  30 


It  would  seem  therefore  that  Vieweg's  assertion  that  the  addition  of 
sodium  chloride  to  the  caustic  soda  solution  increased  the  mercerising 
effect  is  erroneous.  It  has  further  been  demonstrated  that  the  addition 
of  salt  to  the  caustic  lye  always  decreases  the  luster  of  the  mercerised 
cotton. 

In  the  practical  manipulation  of  the  mercerising  process  it  has  been 
found  that  the  impregnation  with  caustic  liquor  is  facilitated  by  the 
addition  of  5  percent  of  alcohol  on  the  weight  of  the  caustic  soda. 

Experiments  have  recently  been  conducted  by  Krais  in  order  to  deter- 
mine the  shrinkage  which  takes  place  in  skeins  of  cotton  yarn  of  various 
qualities  when  treated  in  the 
unstretched  condition  with  mer- 
cerising solutions  of  caustic  soda  of 
various  densities  and  at  varying 
temperatures.  The  skeins  of  yarns 
are  measured  before  and  after  treat- 
ment under  a  uniform  tension  of 
2.2  lbs.  Under  favorable  conditions 
with  respect  to  the  quality  of  the 
yarns,  concentration  of  caustic  soda 
and  temperature,  a  maximum 
shrinkage  of  31.3  percent  is  ob- 
served and  this  in  general  is  some- 
what higher  than  has  been  noted  by 
previous  authorities  experimenting 
on  this  same  problem.  Experiments 
with  single  and  2-ply  yarns  of  the 
same  quality  under  similar  conditions 
showed  that  the  difference  in  shrink-  Fig.  228. — Degree  of  Mercerisation  of  Cot- 
age  of  the  two  was  very  small,  ton  as  Measured  by  Heat  Produced, 
although  generally  in  favor  of   the 

single  yarn.  This  fact  becomes  of  interest  in  the  mercerising  of  piece 
goods  where  the  single  filling  yarn  is  generally  brought  up  on  the  top 
side  of  the  cloth.  Further  experiments  were  made  on  the  influence  of  the 
addition  of  various  substances  to  the  mercerising  solution.  It  was  uni- 
formly observed  that  none  of  these  substances  increases  the  shrinkage 
of  the  yarn  and  consequently  did  not  add  to  the  mercerising  effect  of  the 
caustic  soda.  The  substances  experimented  with  included  alcohols, 
various  metallic  salts,  glycerol,  dextrin,  sodium  carbonate,  etc.  In  fact, 
all  of  them  had  the  effect  of  reducing  the  percentage  of  shrinkage  and 
this  fact  may  be  taken  as  indicating  the  importance  of  a  constant  control 
over  the  purity  of  the  caustic  soda  solution  used  in  the  mercerising  of 
cotton  goods,  especially  when  such  solutions  are  used  continuously,  and 


[20 


■3  15 


X 

'    ° 

/ 

/ 

0  10  20  30  40  50  60 

Grams  of  NaOH  in  100  c.  cms.  or  solution 


602 


MERCERISED   COTTON 


where   it   may   thus   become   contaminated   by   the   gradual   formation 
of  salts. 

Fabrics  of  vegetable  fibers  (cotton  or  linen)  may  also  be  mercerised  in 
patterns  by  printing  on  certain  compounds  capable  of  resisting  the  action 
of  the  caustic  soda  in  the  subsequent  mercerising  process.  Resists  suitable 
for  this  purpose  are,  in  the  first  place,  organic  compounds  which  readily 
coagulate,  such  as  albumen  and  casein;  and,  secondly,  such  salts,  acids,  or 
oxides  which  may  act  by  neutralising  the  caustic  alkali,  or  from  which  a 

hydrate  may  be  precipitated  on  the 
fabric  by  its  action.  Such  com- 
pounds, for  instance,  as  the  salts 
of  aluminium  or  zinc,  organic  acids, 
and  the  oxides  of  zinc,  aluminium,  or 
chromium  are  quite  suitable.  Very 
beautiful  effects  are  said  to  be  ob- 
tainable by  this  process. 

Barratt  and  Lewis  ^  have  endeav- 
ored to  determine  the  degree  of  mer- 
cerisation  of  cotton  by  measuring 
the  heat  produced  in  the  reaction 
of  the  caustic  soda  solution  on  the 
fiber.  An  ingenious  apparatus  pro- 
vided with  electro-thermometric  de- 
vice was  employed.  The  main 
conclusions  were  that  the  "heat  of 
mercerisation  "  of  cotton  by  caustic 
soda  solutions  increases  with  the 
strength  of  the  solution,  but  is  not 
proportional  to  it.  There  are  two 
inflections  in  the  curve;  the  first 
is  between  10  and  15  percent  of 
caustic  soda,  indicating  a  rapid 
increase  in  the  heat  produced  in 
that  region,  and  this  apparently  corresponds  to  the  point  at  which  true 
mercerisation  takes  place.  The  other  inflection  is  at  about  30  percent  of 
caustic  soda  and  marks  the  upper  limit  of  solutions  ordinarily  employed  for 
mercerising.  The  following  curves  are  given  in  connection  with  these 
measurements  (Figs.  228,  229,  and  230). 

12.  Temperature    of   Mercerising. — The   temperature    at    which   the 

reaction  is  carried  out  should  not  be  higher  than  the  usual  atmospheric 

degree;  in  fact,  it  has  been  recommended  to  lower  the  temperature  of  the 

caustic  soda  solution  by  the  addition  of  ice,  but  this  procedure  does  not 

1  Jour.  Text.  Inst.,  1922,  p.  113. 


30 

I 

y 

1 

c 

1 

_> 

.  n 

o 

/ 

/ 

w 
B 
2 
to 

/ 

1 

1 

/ 

1 

/ 

f 

h 

' 

"i 
^1,. 

1 

mlO 

B 
2 

o 

J 

1 

/ 

'  1 

/ 

J 

0  10  20 

NaOH  %  by  weight- 


30 


40 


60 


Fig.  229. — Degree  of  Mercerisation  as  Given 
by  Mass  of  Caustic  Soda  Taken  Up  by 
Cotton:    (1)  Leighton;    (2)  Vieweg. 


TEMPERATURE   OF   MERCERISING 


603 


appear  to  add  anything  of  material  advantage.  At  elevated  temperatures 
caustic  soda  appears  to  exert  a  destructive  effect  on  cotton,  probably  due 
to  the  formation  of  oxycellulose  through  hydrolysis  and  subsequent 
oxidation.  Beyond  a  certain  temperature  the  mercerising  effect  rapidly 
diminishes,  and  at  the  boil  it  is  scarcely  appreciable.  The  best  results 
appear  to  be  obtained  when  the  temperature  is  maintained  at  20°  C. 
or  lower.  Above  this  point  the  contraction  of  the  fiber  (which  may  be 
taken  as  a  measure  of  the  degree  of  mercerisation)  grows  less  and  less  with 
rise  of  temperature. 

Lefevre  ^  states  that  a  solution  of  caustic  soda  of  35°  B^.  at  a  low 
temperature  gives  the  same  mercerising  effect  as  a  solution  of  50°  Be. 
at  ordinary  temperatures.  Kurz  con- 
siders that  with  raw  cotton  it  is  advan- 
tageous to  use  cooled  solutions  of  caus- 
tic soda,  but  with  bleached  cotton  it  is 
not  necessary,  as  the  rise  in  tempera- 
ture of  mercerising  the  latter  is  small, 
whereas  with  raw  cotton  a  rise  in  temp- 
erature of  13°to21°  C.  is  to  be  noticed. 

In  practice,  it  is  necessary  that 
the  caustic  soda  solution  should  be 
maintained  at  a  uniform  density  and 
temperature,  otherwise  successive 
lots  of  the  mercerised  material  will 

differ  in  their  degree  of  mercerisation.  Grams  of  NaOH  in  loo  grama  of  Solution 

In  the  case  of  yarns,  this  unevenness  Fig.  230. — Degree  of  Mercerisation  as 
may  not  be  apparent  until  the  material  Measured  by:  (1)  Shrinkage  in  length 
is  dyed.  To  bring  about  a  uniform  "^  ^^^^o"  ^'=^™!  ^2)  Affinity  for  Dyes, 
result  it   is   necessary  to  maintain  a 

constant  circulation  of  the  caustic  liquors  through  the  mercerising  machine 
(whatever  mechanical  system  may  be  employed),  adding  systematically 
the  necessary  amount  of  strong  caustic  at  a  constant  degree  of  density. 
Practice  shows  that  a  pound  of  cotton  yarn  requires  from  0.5  to  0.75  lb. 
of  solid  caustic  soda  (98  percent  NaOH)  for  mercerisation.  As  consider- 
able heat  is  developed  in  the  mercerising  process,  it  may  be  necessary  to 
employ  an  artificial  cooling  device  to  keep  the  temperature  of  the  caustic 
liquor  at  a  constant  point.  This  is  generally  accomplished  by  passing 
the  caustic  liquor  during  its  circulation  through  a  tank  provided  with  a 
coil  of  pipes  supplied  with  cold  water.  It  is  only  necessary  to  keep  the 
caustic  liquor  below  a  temperature  of  75°  F.,  in  order  to  obtain  good  results. 

It  has  been  found  that  the  degree  of  lustering  decreases  very  materially 
with  the  increase  of  temperature,  as  is  shown  graphically  in  the  following 
1  Rev.  Gen.  Mat.  Col,  1902,  p.  1. 


/:x 

^ 

c 

.o 

/ 

V 

2 
1 

01 

u 
o 

/ 

0) 
0) 

o 

/ 

/ 

A' 

604 


MERCERISED  COTTON 


curves  (Fig.  232). ^  On  examining  these  curves  it  will  be  noted  that  a 
characteristic  phenomenon  takes  place  when  we  pass  from  caustic  soda 
solutions  of  15°  Be.  to  those  of  25°  Be.     At  a  concentration  of  15°  Be.  the 


Fig.  231. — Lustering  Machine  for  Skein  Mercerised  Yarn. 


curve  representing  the  contraction  is  convex  toward  the  axes  of  the  co- 
ordinates, whereas  for  concentrations  over  15°  Be.  the  curve  is  concave. 

1  Beltzer,  Rev.  Gen.  Mat.  Col,  1902,  pp.  25  and  34. 


TEMPERATURE  OF   MERCERISING 


605 


At  a  certain  mean  concentration  (20°  Be.)  the  curve  should  become  a 
straight  Hne.^ 

The  following  table  ^  shows  the  contraction  (degree  of  mercerisation) 
of  cotton  yarns  obtained  with  different  concentration  of  caustic  soda  and 
at  diflferent  temperatures  for  periods  of  1,  10,  and  30  minutes.  The 
contraction  is  expressed  in  percentages: 


Density  of  Caustic  Soda  Solutions. 

5°  Be. 

10°  Be. 

15°  Be. 

25°  Be. 

30°  Be. 

35°  Be. 

d 

o 

Duration  of  Mercerising  in  Minutes. 

s 

1 

10 

30 

1 

10 

30 

1 

10 

30 

1 

10 

30 

1 

10 

30 

1 

10 

30 

2 

0 

0 

0 

1 

1 

1 

12.2 

15.2 

16.8 

19.2 

20.1 

21.5 

22.7 

22.7 

22.7 

23.5 

23.0 

23.0 

18 

0 

0 

0 

0 

0 

0 

8 

8.8 

11.8 

19.2 

20.1 

21.1 

22.5 

22.5 

22.5 

23.5 

23.0 

21.0 

30 

0 

0 

0 

0 

0 

0 

4.6 

4.6 

6.0 

19.2 

20.3 

19.0 

19.8 

19.8 

19.8 

20.7 

20.5 

20.1 

80 

0 

0 

0 

0 

0 

0 

3.5 

3.7 

3.8 

13.4 

13.7 

14.2 

15.5 

15.5 

15.5 

15.5 

15.5 

15.4 

A  modification  of  the  mercerising  process,  used  not  so  much  for  the 
production  of  a  luster  as  to  give  a  transparent  finish,  is  that  described  by 
Heberlein.-^  It  was  found  that  by  treating  cotton  fabrics  with  caustic 
soda  solution  cooled  to  below  0°  C,  and  of  such  concentration  as  would 
mercerise  the  cotton  at  the  ordinary  temperature  (50°  to  55°  Tw.),  the 
cotton  acquires  a  translucent  appearance  which  it  retains  even  after 
washing  and  drying.  The  treatment  is  usually  for  one  minute  at  a  tem- 
perature of  -  10°  C.  Pattern  effects  may  be  obtained  by  printing  a 
reserve  on  the  fabric  (such  as  a  gum  thickening)  and  then  treating  with 
the  cooled  caustic  soda  solution.  This  treatment  is  particularly  employed 
not  so  much  as  a  process  in  itself,  but  as  a  preliminary  process  in  the 
production  of  the  transparent  "  Swiss  Finish  "  (also  known  as  "  Per- 
manent Finish  ")  with  concentrated  sulfuric  acid.  The  treatment  with 
the  caustic  soda  solution  no  doubt  greatly  increases  the  absorption  of 
the  acid  so  as  to  allow  it  to  act  quickly  throughout  the  fiber.  The  treat- 
ment with  the  acid  also  makes  the  fabric  permanently  stiff  by  parch- 
mentising  the  fiber,  and  this  quality  it  retains  even  after  repeated  washings. 

1  Beltzer,  L'Ind.  Text.,  1908,  p.  118. 

^  Gardner,  Die  Mercerisation  der  Baumwolle. 

^  See  Brit.  Pat.  108,071. 


606 


MERCERISED  COTTON 


13.  Time   of  Mercerising. — The  mercerising  action  of   caustic   soda 
is  rather  a  rapid  one,  as  it  requires  only  a  few  minutes  for  its  completion; 

in  fact,  it  appears  to 
take  place  simultane- 
ously with  the  impreg- 
nation of  the  fiber  by 
the  liquid.  In  ten 
minutes  mercerisation 
is  practically  com- 
plete, and  lengthen- 
ing of  the  time  does 
not  increase  the  mer- 
cerising effect ;  in  fact, 
too  long  a  contact  of 
the  cotton  with  the 
caustic  alkali  is  to  be 
avoided,  especially  if 
the  impregnated  fiber 
is  exposed  to  the  air, 
as  there  is  danger  of 
a  breaking  down  of 
the  cellular  structure 
and  a  consequent  de- 
terioration in  the 
strength  of  the  fiber. 
The  time  of  immer- 
sion to  produce  the 
maximum  effect  also 
appears  to  be  inde- 
pendent of  both  the 
temperature  and  the 
concentration  of  the 
alkali. 

Fig.  232.— Curves  Showing   Contraction   of   Cotton    Mer-  ^^^  small    periods 

cerised   at  Different   Temperatures  and  with  Different  of     immersion     the 
Concentrations  of  Alkah.  contraction   varies    in 

proportion  to  the  time 
up  to  about  twenty  seconds;  the  luster  reaches  its  maximum  in  about 
this  period  of  time.^ 

Miller  ^  has  established  the  fact  that  cotton  absorbs  less  alkali  after  a 
prolonged  immersion  than  with  a  shorter  immersion.     When  100  grams 

1  Beltzer,  Les  Malihres  Cellulosiques,  p.  65. 

2  Berichte,  1907,  p.  7902. 


340 

\ 

\ 

302  ■ 

N 

\\ 

IQ)^ 

\              \ 

\               \ 

195 
iTRn 

\ 

\ 

\ 

^^K9 

\ 

\v 

1 

\ 

\ 

a 

^120  - 

\ 

\ 

.3 

\ 

\ 

gno- 

\ 

\\ 

o 

O    BK  - 

\l 

\\\ 

\ 

\ 
\ 

1 

V. 

\ 

\ 

\ 

^     0 
Y 

2           1 

8     3 

0                     6 
Temper 

0           s 
atures. 

0           10 

K)          120 

35  Be. 


30°Be. 


25°Be. 


20°  Be. 
15°  Be. 


TENSION   IN   MERCERISING 


607 


of  cotton  were  steeped  in  caustic  soda  solution  of  28°  Be.  the  absorption 
of  alkali  was  as  follows : 

„.  Alkali  Absorbed, 

Percent 

30  seconds 2. 69 

1  hour 2.53 

24  hours 2.50 

The  following  table  shows  the  relations  existing  between  the  con- 
traction of  the  yarn,  the  amount  of  Benzopurpurine  fixed,  and  the  dura- 
tion of  mercerising.  The  mercerising  was  done  with  caustic  soda  solu- 
tion of  29°  Be. 


Time  of  Mercerisa- 

Contraction, 

Dyestuff  Fixed, 

tion,  Seconds. 

Percent. 

Percent. 

1 

15.7 

3.24 

10 

17.4 

3.62 

20 

25.0 

3.80 

40 

25.0 

3.89 

60 

25.0 

3.91 

120 

27.0 

4.10 

In  a  detailed  study  of  the  changes  undergone  by  single  cotton  fibers 
when  treated  with  solutions  of  caustic  soda.  Willows,  Barratt  and  Parker  ^ 
have  shown  that  the  action  of  the  caustic  soda  in  mercerising  is  by  no 
means  as  rapid  as  is  commonly  supposed,  but  nevertheless  is  practically 
complete  at  the  end  of  three  minutes.  Solutions  of  less  strength  than 
22°  Tw.  cause  elongation,  but  rapid  penetration  and  great  contraction 
occur  with  solutions  of  30°  to  35°  Tw.  Solutions  of  60°  Tw.  act  very 
slowly,  and  very  concentrated  solutions  (86°  Tw.)  have  very  little  effect. 

14.  Tension  in  Mercerising. — There  are  two  ways  in  which  the  tension 
may  be  applied  in  mercerising:  (a)  The  material  may  be  held  in  a  state 
of  tension  during  the  time  of  its  treatment  with  the  caustic  alkali,  and 
until  the  alkali  has  been  washed  out,  in  which  case  the  tension  should  be 
so  maintained  that  the  material  cannot  shrink;  (6)  the  tension  may  be 
applied  after  the  material  has  been  treated  with  the  caustic  alkali,  but 
before  the  latter  is  washed  out,  in  which  case  sufficient  tension  should 
be  exerted  to  stretch  the  material  back  to  its  original  length.  If  the 
tension  is  not  applied  until  after  the  alkali  has  been  removed  from  the 
fiber,  no  lustering  effect  is  produced;  it  is  absolutely  essential  that  the 

^Jour.  Text,  hid.,  1922,  p.  229. 


608 


MERCERISED   COTTON 


stretching  should  take 
place  while  the  fiber 
is  in  the  form  of  an 
alkali-cellulose,  and 
before  it  has  been  con- 
verted by  treatment 
with  water  into  hy- 
drated  cellulose. 

According    to   the 
experiments    of    Her- 
big,      the     stretching 
force      necessary     to 
keep  the  cotton  in  its 
original  length  during 
mercerisation   is  only 
from  a    quarter  to  a 
third  of  that  necessary 
to  do    the   stretching 
after      mercerisation ; 
but  there   appears  to 
be  no  appreciable  di.'- 
ference    in  the   luster 
obtained.      It    would 
appear,  however,  that 
stretching    beyond    a 
certain    point    ceases 
to  increase  the  luster, 
and    to     obtain    the 
maximum      lustering 
effect  it  is  not  neces- 
sary   to     stretch  the 
cotton     back    to    its 
original  length.     Hcr- 
big     concluded    that 
stretching  during  mer- 
cerisation is  disadvan- 
tageous, and  it  is  best 
to  mercerise  the  yarn 
loose,   wring    it,    and 
only  stretch  while  rins- 
ing,   as   the   required 
stretching  force  is  then 


quite  small.      The  best  time  for  stretching,  then,  is  during  the  conversion 


TENSION   IN   MERCERISING 


609 


610 


MERCERISED  COTTON 


of  the  soda-cellulose  into  the  hydrocellulose.  If  the  stretching  does  not 
take  place  until  after  rinsing,  almost  twice  the  force  is  necessary  to  restore 
the  yarn  to  its  original  length,  as  when  in  contact  with  the  lye,  and  the 
luster  is  decidedly  inferior.  The  stretching  force  also  appears  to  depend 
on  the  twist,  being  greater  in  proportion  as  the  twist  is  harder. 


Fig.  235. — Three-roll  Mercerising  Padder  for  Piece  Goods.    (Text.  Fin.  Mchy.  Co.) 


Herbig  gives  a  summary  of  his  experimental  results  as  follows : 

1.  Loose  yarn  mercerised  without  any  stretching,  whether  long-  or  short-stapled, 
and  whether  with  or  without  a  hard  twist,  has  less  luster  than  unmercerised  yarn. 
But  even  with  a  very  slight  tension  the  luster  is  greater. 

2.  Both  with  long-  and  short-stapled  cotton  the  luster  only  becomes  marked  when 
the  stretching  force  is  sufficient  to  bring  the  yarn  back  to  its  original  length. 

3.  Stretching  beyond  the  original  length  does  not  give  any  increase  in  luster. 

4.  Considerable  difference  is  observable  in  the  stretching  force  needed  between 
loose  mercerisation  followed  by  stretchmg  in  the  lye,  and  keeping  the  cotton  at  its 
original  length  during  mercerisation,  as  in  the  latter  case  only  one-third  to  one-quarter 
of  the  force  is  necessary  to  produce  the  silky  luster. 

5.  The  stretching  of  the  yarn  requires  only  a  small  force  when  mercerised  loose 


WASHING  AS  A  PROCESS  IN  MERCERISING 


611 


and  if  applied  when  rinsing  is  actually  in  progress;   for  the  best  time  for  stretching  is 
during  the  conversion  of  the  soda-cellulose  into  hydrocellulose. 

6.  When  rinsing  is  over,  twice  as  much  force  is  needed  to  restore  the  original  length 
as  is  required  for  yarn  still  in  contact  with  the  lye;  and  yarns  so  treated  contract 
somewhat  on  drying,  and  exhibit  an  inferior  luster. 

7.  The  stretching  force  necessary  in  mercerising  yarn  varies  with  the  twist,  and 
in  general  is  greater  in  proportion  as  the  twist  is  harder. 

8.  The  production  of  the  silky  luster  docs  not  depend  primarily  on  the  amount  of 
force  employed  in  stretching,  as  soft  yarn  with  only  a  small  amount  of  twist  can  be 
given  a  luster. 

9.  The  production  of  the  silky  luster  is  independent  of  the  cotton  being  long-  or 
short-stapled,  as  short-stapled  American  cotton  with  even  a  loose  twist  can  be  given 
a  silky  luster. 

10.  The  production  of  a  high  degree  of  luster  depends  to  a  considerable  extent  on 
the  fineness  of  the  fiber  and  its  natural  luster.  This  is  apparent  in  mercerising  Sea- 
island  and  Egyptian  cottons. 

Grosheintz  ^  conducted  some  interesting  experiments  on  the  con- 
tractive force  exerted  by  cotton  fabrics  in  mercerising.  The  experiments 
were  made  on  pieces  of  cotton  fabric  5  cm.  wide  along  the  filling  and  of 
such  length  in  the  warp  that  just  10  cm.  were  held  between  the  jaws  of  a 
tensile-strength  machine.  The  strips  were  fixed  in  such  a  manner  as  to 
be  slightly  stretched.  The  mercerising  was  affected  by  moistening  the 
strips  in  the  machine  with  the  caustic  soda  solution  with  a  glass  rod. 
The  following  results  were  obtained  with  a  calico: 


1.  Caustic  soda  71°  Tw 

2.  Caustic  soda  71°  Tw.,  90  cc.  )^ 
Water,  10  cc.  J 

3.  Caustic  soda  71°  Tw.,  80  cc.  T 
Water,  20  cc.  J 

4.  Caustic  soda  71°  Tw.,  70  cc.  \ 
Water,  30  cc.  J 

5.  Caustic  .soda  71°  Tw.,  60  cc.  1 
Water,  40  cc.  J 

6.  Caustic  soda  71°  Tw.,  50  cc.  "1 
Water,  50  cc.  / 


Tension 

Duration  of 

in 

Contraction, 

Kilos. 

Minutes. 

5.3 

4 

5.0 

5 

4.2 

5 

4.0 

5 

3.5 

5 

3.0 

5 

15.  Washing  as  a  Process  in  Mercerising.— By  the  washing  of  the 
material  after  steeping  in  caustic  alkali,  a  twofold  object  is  gained.  In 
the  first  place,  the  action  of  the  water  on  the  alkali-cellulose  is  to  effect 
a  chemical  transformation  into  cellulose  hydrate,  and  this  action  is  as 

^Bull.Soc.Ind.Mulh.,  1902. 


612 


MERCERISED  COTTON 


be 

.3 


S3 
o 
O 

I 

CD 

CO 

(M 

d 


really  essential  to  mer- 
cerising as  the  action 
of    the    caustic    soda 
itself.     In  the  second 
place,  the  washing   is 
conducted      for      the 
purpose   of   removing 
all   excess    of    caustic 
alkali  from    the    ma 
terial.      Caustic  soda 
is  held  quite  tenacious- 
ly by  cotton,  and  it  re- 
quires a  very  thorough 
and       long-continued 
washing  to  remove  the 
last  traces  of  this  com- 
pound.     In  order  to 
shorten  the  period  re- 
quired for  washing,  it 
is  customary  to   give 
the  cotton  first  a  rins- 
ing   in    warm    water, 
after  which    the    ten- 
sion may  be  relieved, 
and  then  to  wash  with 
cold  water  and  then 
with  acidulated  water, 
using  either  sulfuric  or 
hydrochloric  acid  for 
this  purpose.     The  use 
of  acetic    and  formic 
acids  have  also  been 
tried,   but    their    ex- 
pense is  higher  than 
sulfuric    acid.      The 
strength   of   the   acid 
bath  should  be  so  ad- 
justed that  the  caustic 
alkali     is    completely 
neutralised       without 
unnecessarily     acidu- 
lating the  cotton.    To 
remove  the  excess  of 


SCROOPING  OF  MERCERISED  COTTON  613 

acid,  however,  and  prevent  subsequent  tendering  of  the  fiber,  the  cotton 
should  be  thoroughly  washed  after  treatment  with  the  acid  and  finished 
by  soaping  or  oiling. 

When  mercerised  cotton  is  rinsed  with  ammonia  instead  of  water  it 
retains  its  gelatinous,  parchmentlike  consistency  throughout  the  rinsing, 
and  can  be  stretched  to  its  original  length  without  breaking.  If  the 
cotton  is  then  rinsed  with  water  while  still  stretched,  the  fiber  regains  its 
original  appearance  and  acquires  a  luster  as  good  as  that  obtained  in  the 
usual  way. 

16.  Scrooping  of  Mercerised  Cotton. — If  the  cotton  is  treated  with  a 
soap  solution  and  then  with  dilute  acetic  or  formic  acid  and  dried  without 
washing  out  the  excess  of  acid,  the  fiber  will  be  found  to  have  acquired  a 
silklike  "scroop."  If  other  acids, •  and  especially  mineral  acids,  are 
employed  for  washing,  a  subsequent  rinsing  with  fresh  water  and  soaping 
is  necessary  for  the  purpose  of  neutralising  all  of  the  acid,  which  would 
otherwise  seriously  tender  the  goods  on  drying,  unless  the  amount  of  acid 
employed  is  so  accurately  adjusted  as  not  to  leave  any  free  acid  in  the 
fiber. 

Mercerised  cotton  goods  that  have  been  dyed  with  sulfur  colors  and 
then  treated  with  soap  and  acid  baths  in  order  to  impart  scroop,  are 
liable  to  be  tendered  on  long  storing.  To  avoid  this  the  addition  of 
sodium  acetate  (5  to  10  grams  per  liter)  to  the  acid  bath  (10  grams  of  acetic 
acid  per  liter)  has  been  suggested.  According  to  an  English  patent 
No.  11,729  of  1909,  a  better  method  is  to  work  the  dyed  cotton  in  a  soap 
bath,  hydroextract,  and  without  washing,  treat  in  a  bath  containing  17 
grams  of  lactic  acid  and  7  grams  of  soda  ash  per  liter  for  twenty  minutes, 
hydroextract,  and  dry  without  washing. 

A  "scroop"  may  also  be  imparted  to  mercerised  yarn  as  follows: 
The  yarn  is  soaped  in  a  lukewarm  (120°  F.)  bath  containing  8  percent  of 
olive  oil  soap  and  1  percent  of  starch  (on  the  weight  of  the  yarn);  then 
hydroextracted  and  treated  for  ten  minutes  in  a  bath  containing  100 
gallons  water,  3  lbs.  tartaric  acid,  and  10  lbs.  sodium  acetate.  Hydro- 
extract  and  dry  without  rinsing. 

There  have  been  a  number  of  methods  suggested  for  imparting  a  scroop 
or  silklike  crunch  to  dyed  hoisery,  more  especially  when  this  hosiery  is 
made  up  of  mercerised  cotton  yarns.  The  scrooping  process  is  carried 
out  as  a  subsequent  operation  to  that  of  dyeing,  and  is  in  reality  a  final 
process  of  finishing.  The  methods  which  have  generally  been  suggested 
are  those  involving  the  use  of  various  organic  acids  such  as  acetic,  lactic, 
tartaric,  and  formic.  In  fact,  almost  any  acid  acting  on  the  cotton  fiber 
and  allowed  to  dry  will  impart  a  silklike  crunch  to  the  material.  In  the 
case  of  the  stronger  mineral  acids,  such  as  sulfuric,  hydrochloric,  and  nitric, 
the  action  extends  too  far  and  although  a  very  decided  silklike  crunch  is 


614  MERCERISED   COTTON 

developed,  the  cellulose  of  the  fiber  is  attacked  to  such  an  extent  as  to 
cause  chemical  disintegration,  resulting  in  the  tendering  or  complete 
destruction  of  the  cotton  material. 

The  organic  acids  mentioned  above  do  not  have  the  same  deleterious 
effect  in  tendering  the  cotton  fiber,  but  if  used  alone  they  do  not  produce 
sufficient  scroop  to  make  the  process  really  worth  while.  If,  however, 
the  organic  acids  are  employed  in  connection  with  a  soap  bath,  it  has  been 
found  possible  to  produce  quite  a  satisfactory  scroop  without  apparent 
injury  to  the  strength  of  the  fiber.  The  cause  of  the  scroop  produced  on 
cotton  by  this  action  of  acids  is  probably  a  certain  hardening  of  the  surface 
of  the  fiber  so  that  when  it  is  bent  it  produces  a  crackling  or  crunching 
sound.  This  hardening  may  be  enhanced  sometimes  by  the  use  of  a  little 
glue  or  starch  solution  in  connection  with  the  acid  and  soap  treatment, 
though  these  substances  are  also  liable  to  stiffen  the  material.  In  cases 
where  such  a  stiffening  effect  is  not  desired,  their  use  would  not  be  possible. 

The  character  of  the  yarn  also  has  considerable  to  do  with  the  degree 
of  scroop  which  can  be  produced  by  chemical  treatment.  Mercerised 
yarn  can  be  scrooped  to  a  greater  degree  and  with  more  readiness  than 
unmercerised.  Soft  single-ply  unmercerised  yarn  can  hardly  be  scrooped 
at  all,  whereas  hard-twisted  and  lisle  unmercerised  yarns  can  be  given  a 
fair  amount  of  scroop.  The  degree  of  scroop  is  also  influenced  by  the 
heat  used  in  the  drjdng  of  the  material.  It  is  well  to  dry  as  hot  and 
as  quickly  as  possible,  as  these  conditions  will  tend  to  harden  the  surface 
of  the  fiber  to  a  greater  degree  and  thus  produce  a  more  pronounced 
scrooping  effect.  A  number  of  recipes  for  cotton,  more  especialty  mer- 
cerised cotton,  have  been  suggested  and  the  following  includes  some  of 
these : 

(1)  The  dyed  goods  are  passed  through  a  soap  bath  containing  1  oz.  of  hard  soap 
per  gallon.  The  goods  should  be  worked  in  this  soap  solution  until  thoroughly  imjireg- 
nated  and  at  the  temperature  of  about  140°  F.  The  goods  are  then  removed  and  the 
excess  of  liquor  is  either  scjueezed  out  or  the  goods  are  placed  in  a  hydroextractor  and 
then  without  rinsing  worked  m  a  second  bath  containing  2h  ozs.  of  lactic  acid  and 
3  ozs.  of  caustic  soda  per  gallon.  The  goods  are  worked  in  this  bath  for  twenty 
minutes  at  a  temperatm-e  of  140°  F.  and  then  hydroextracted  and  dried  without 
rinsing. 

(2)  The  soaping  of  the  material  is  carried  out  as  above  described,  but  the  second 
bath  consists  of  1  oz.  of  formic  acid  per  gallon,  the  material  being  worked  therein  for 
twenty  minutes  at  the  room  temperature  and  then  hydroextracted  and  dried  without 
rinsing. 

(3)  It  is  claimed  that  a  permanent  and  pronounced  scroop  can  be  given  to  cotton 
by  treating  the  material  with  a  soap  bath  as  above  described  and  then  giving  a  cold 
bath  containing  1  oz.  of  tartaric  acid  per  gallon,  removing  the  goods  after  fifteen 
minutes,  hydroextracting  and  drying  without  rinsing.  A  greater  scrooping  effect  can 
be  produced  if  sizing  materials  are  added  to  the  acid  bath  which  may  then  contain  1  oz. 
of  tartaric  acid,  ^  oz.  of  glue  and  |  oz.  potato  starch.     It  is  said  that  the  effect  can 


QUALITY   OF   FIBER   FOR   MERCERISING  615 

be  still  further  enhanced  by  treating  the  goods  first  with  2  to  3  percent  of  tannic  acid 
and  1  to  li  percent  of  antimony  salt  and  then  soaping  and  treating  with  tartaric  acid 
as  just  described. 

(4)  According  to  Ger.  Pat.  242,933,  mercerised  cottons  may  be  scrooped  in  the 
following  manner.  The  goods  are  first  soaped  as  usual,  squeezed  out  or  slightly  rinsed, 
and  then  treated  in  one  of  the  following  four  baths,  after  which  they  are  wrung  out 
or  hydroextracted  and  dried  without  rinsing: 

(a)  2\  ozs.  of  lactic  acid  and  1  oz.  of  soda  ash  per  gallon. 

(6)   1  oz.  of  lactic  acid  and  2  ozs.  of  sodium  lactate  per  gallon. 

(c)  3  ozs.  of  tartaric  acid  and  2  ozs.  of  soda  ash  per  gallon. 

(d)  1  oz.  of  tartaric  acid  and  §  oz.  of  sodium  tartrate  per  gallon. 

In  case  the  goods  have  been  dyed  with  sulfur  dyes,  it  is  said  that  this  process 
not  only  gives  a  distinct  scroop  but  also  protects  the  dyed  material  from  subsequent 
tendering. 

(5)  Another  process  which  has  been  suggested  for  the  scrooping  of  dyed  cotton 
material  is  to  work  in  successive  baths  of  calcium  acetate,  soap  and  acetic  acid  in  the 
following  general  manner.  Run  the  goods  for  fifteen  minutes  at  110°  F.  in  a  solution 
of  calcium  acetate  of  7.9°  Tw.  Squeeze  lightly  but  do  not  rinse.  Then  work  for  fifteen 
minutes  at  120°  to  140°  F.  in  a  bath  containing  40  percent  of  soap  on  the  weight  of  the 
goods.  Again  squeeze  lightly  or  hydroextract  and  pass  into  a  cold  bath  containing 
one  part  of  acetic  acid  to  10  parts  of  water.     Finally  squeeze  and  dry  without  rinsing. 

(6)  Another  process  which  has  been  suggested  is  the  use  of  boric  acid  in  the  follow- 
ing manner:  100  lbs.  of  the  cotton  goods  are  worked  in  a  bath  containing  16  to  20  lbs. 
of  boric  acid  for  half  an  hour  at  70°  F.  The  goods  are  then  hydroextracted  and  dried 
without  rinsing  or  the  effect  can  be  enhanced  by  using  two  baths  as  follows:  First, 
working  the  material  in  a  solution  containing  1^  ozs.  of  soap  per  gallon,  hydro- 
extracting  and  second  passing  into  a  bath  containing  l-i  ozs.  of  boric  acid  per  gallon, 
then  hydroextracting  and  drying  without  rinsing. 

17.  Quality  of  Fiber  for  Mercerising. — The  character  of  the  fiber 
employed  has  a  considerable  influence  on  the  success  of  the  mercerising 
process.  From  the  very  nature  of  the  fact  that  a  considerable  degree  of 
tension  must  be  applied  to  the  fiber  during  the  process  in  order  to  obtain 
the  desired  luster,  it  would  be  natural  to  expect  that  the  longer  the  staple 
of  the  fiber  the  more  readily  would  it  lend  itself  to  the  requirements  of  the 
operation.  And  such,  indeed,  is  found  to  be  the  case;  the  long-stapled 
Sea-island  and  Egyptian  varieties  of  cotton  are  those  especiallj^  adapted 
for  use  in  the  preparation  of  mercerised  cotton,  while  the  shorter-stapled 
varieties  are  but  little  employed  for  this  purpose,  as  the  luster  obtained 
with  them  is  by  no  means  as  pronounced. 

Besides  Sea-island  and  Egyptian  cottons,  however,  there  are  large 
quantities  of  the  long-stapled  American  peeler  cottons  employed  for 
mercerising  in  the  United  States.  Certain  varieties,  such  as  the  Allen- 
seed  cotton  of  Mississippi,  are  especially  adapted  to  pin-poses  of  mer- 
cerising, and  if  proper  care  be  taken  in  the  preparation  of  the  yarn,  very 
good  effects  may  be  obtained.  Boucart  ^  gives  the  following  reasons  why 
only  long-stapled  cotton,  and  that  only  in  particular  counts,  gives  good 
1  Rev.  Gen.  Mat.  Col,  1902,  p.  34. 


616 


MERCERISED   COTTON 


results  on  mercerisation.  A  simple  thread  consists  of  a  sort  of  twisted 
wick  composed  of  nearly  parallel  fibers.  The  twist  depends,  as  regards 
the  angles  it  makes  with  the  length  of  the  thread,  both  upon  the  kind  of 
cotton  and  upon  the  count  of  the  yarn.  Of  the  two  sorts  of  simple  yarns, 
warp-yarns  have  more  cohesion  among  their  elements  than  tensile  strength, 
while  the  reverse  is  the  case  with  weft-yarns.  The  result  is  that  under 
gradually  increasing  tension  weft-fibers  slide  past  one  another  without 
breaking,  but  warp-fibers  break  before  any  such  occurrence  takes  place. 
The  degree  of  twist  also  depends  on  the  mean  staple,  and  the  angle  between 
the  thread  and  the  axis  at  any  point  is  proportional  to  the  length  of  the 
thread.  The  degree  of  twist  which  is  required  to  make  the  cohesion 
exceed  the  tensile  strength  depends  natiu'ally  on  the  strength  of  the  fiber. 
The  mercerising  process  tends  to  shorten  each  individual  fiber,  and  this 
shortening  is  resisted  by  tension  in  the  direction  parallel  to  the  axis  of  the 


Fig.  237. — Piece  Mercerising  Machine  with  Krais  Caustic  Recovery  System. 

thread.  Hence  the  greater  the  angle  the  thread  makes  with  that  axis 
the  less  is  the  effect  of  the  tension,  and  if  any  portion  of  the  fiber  is  at 
right  angles  to  the  axis  it  is  not  affected  by  the  tension  at  all.  Hence  a 
simple  warp-thread  can  only  receive  a  medium  amount  of  gloss  from 
mercerisation,  this  is  less  as  the  twist  is  greater.  Slightly  twisted  threads 
should  give  the  best  luster,  but  if  the  cohesion  of  the  fibers  is  less  than 
the  contractile  force  exerted  by  the  mercerising,  the  fibers  slip  past  each 
other  and  no  luster  is  produced.  But  if  the  weft-threads  are  fixed,  as  in 
piece  goods,  they  take  a  better  luster  than  the  warp,  although  the  latter  is 
usually  made  of  better  cotton.  Short-stapled  cotton  acquires  a  less 
degree  of  luster  because  it  must  be  more  tightly  twisted.  The  best  luster 
of  all  is  obtained  with  twofold  twist,  in  which  the  outer  fibers  lie  parallel 
to  the  axis,  and  the  yarn  should  be  well  singed  to  remove  projecting  fibers. 
The  quality  of  being  mercerised  is  not  an  inherent  property  of  any 
special  variety  of  cotton,  as  was  formerly  supposed  to  be  the  case;  any 
variety  of  cotton  is  capable  of  mercerisation,  the  essential  being  that  the 
fiber  shall  be  maintained  in  a  state  of  tension.     In  order  that  this  condition 


QUALITY    OF   FIBER   FOR   MERCERISING 


617 


618  MERCERISED   COTTON 

be  realised  with  short-stapled  fibers,  the  yarn  operated  upon  must  be 
tightly  twisted  in  order  to  present  sufficient  cohesion  among  the  individual 
fibers  to  allow  of  the  high  tension  required;  this,  on  the  other  hand, 
prevents  an  even  and  thorough  penetration  of  the  caustic  alkali  into  the 
substance  of  the  fiber,  so  that,  on  the  whole,  the  results  obtained  with 
short-stapled  fibers  are  not  at  all  comparable  with  those  of  the  long-stapled 
varieties. 

The  preparation  by  combing  of  cotton  for  mercerisation  has  a  con- 
siderable influence  on  the  subsequent  luster  of  the  yarn.  Sea-island 
cotton  possesses  a  rather  silky  fiber  to  begin  with,  and  this  is  made  more 
adaptable  to  the  production  of  a  high  luster  by  combing,  in  which  operation 
the  fibers  are  arranged  parallel,  and  still  further  by  gassing,  which  burns 
off  the  minute  outer  hairs.  Yarns  possessing  considerable  luster  were 
made  in  this  manner  with  fine  counts  of  Sea-island  cotton  long  before  the 
discovery  of  lustering  by  mercerisation,  and  it  was  always  recognised  that 
the  parallelism  of  the  fibers  so  obtained  by  combing  (and  sometimes  a 
second  combing)  was  a  great  factor  in  the  production  of  a  silky  and  lustrous 
yarn.  By  later  improvements  in  the  manner  of  applying  the  tension, 
hov/ever,  it  would  seem  that,  by  realising  the  proper  mechanical  conditions, 
even  cotton  of  comparatively  short  staple  will  be  capable  of  being  mer- 
cerised in  a  more  successful  manner  than  heretofore. 

Lowe,  in  a  study  on  the  inter-relation  of  mercerisation  and  spinning  of 
yarns,  finds  that  when  yarn  is  mercerised  to  "  spinner's  length  "  and 
washed  without  tension  it  becomes  (1)  more  slender,  (2)  stronger,  (3)  more 
uniform,  and  (4)  it  receives  more  twist;  in  other  words,  mercerising  has 
the  effect  of  further  spinning  the  yarn.  In  favorable  cases,  the  increase 
in  twist  may  be  from  10  to  17  or  24  to  40  per  inch;  the  increase  of  strength 
may  be  14.25  percent,  and  the  diameter  may  be  decreased  by  18  percent. 
The  effects  are  due  to  the  closer  packing  of  the  fibers  in  the  plastic  state. 

18.  Methods  of  Mercerising. — Cotton  is  largely  mercerised  both  in 
the  form  of  yarn  and  the  woven  fabric.  Yarn  mercerising  may  be 
carried  out  in  the  skein  or  in  the  warp;  the  latter  being  the  favorite  process 
in  use  in  America,  while  in  Europe  nearly  all  yarn  mercerising  is  done  in 
the  skein.^     Machines  for  skein  mercerising  are  so  arranged  that  the 

1  The  revolving  type  of  skein  mercerising  machine  of  Kleinewefer  is  provided  with 
eight  pairs  of  rollers  revolving  horizontally  about  a  central  axis  and  requires  the 
attention  of  only  one  operator  for  a  production  up  to  2400  lbs.  per  day.  In  the  first 
position  the  yarn  is  placed  on  the  rollers;  these  move  apart  and  give  the  required 
tension  to  the  yarn;  in  the  second  position  the  caustic  soda  treatment  is  given,  which 
is  repeated  in  the  third  position;  in  the  fourth  position  the  yarn  is  squeezed  and 
washed  with  the  least  quantity  of  water  to  provide  a  wash-water  highly  concentrated 
for  subsequent  recovery;  in  the  fifth  and  sixth  positions  washings  with  warm  and 
cold  water  are  given;  in  the  seventh  position  the  yarn  is  soured,  and  finally  washed 
again  in  the  eighth  position,  where  it  is  withdrawn  from  the  machine. 


METHODS   OF   MERCERISING  619 

hanks  of  yarn  are  stretched  between  revolving  rollers  and  successively 
subjected  to  the  action  of  caustic  soda,  a  washing  with  warm  water,  and 
finally  a  washing  with  cold  water.  The  operation  of  most  forms  of 
machines  is  entirely  automatic.^  In  another  form  of  apparatus  the 
hanks  are  placed  over  a  perforated  horizontal  drum;  the  latter  is  then 
revolved  at  a  high  rate  of  speed  while  the  solution  of  caustic  soda  is 
applied  from  the  inside  and  the  washing  with  water  is  done  in  the  same 
manner  (Fig.  217).  The  tension  in  this  machine  is  produced  by  the 
centrifugal  force  arising  from  the  high  speed  of  rotation .^  When  mer- 
cerised in  the  form  of  warps  the  yarn  is  passed  continuously  through  a  series 
of  vats  in  which  it  is  boiled-out,treated  with  caustic  soda,  washed,  treated 
with  dilute  acid,  and  finally  finished  with  soap.  The  tension  is  obtained 
by  a  series  of  squeeze-rolls.  Warp  mercerising  is  much  cheaper  than 
skein  mercerising,  and  uniform  results  are  more  easily  obtained.  Cloth 
mercerising  is  carried  out  on  an  apparatus  resembling  a  long  tenter  frame 
so  that  the  cloth  is  kept  in  tension  by  a  continuous  series  of  side  clamps. 
As  the  cloth  moves  along  this  frame  it  is  subjected  to  the  various  treat- 
ments of  caustic  soda,  washing  with  water,  and  neutralising  with  dilute 
acid.  In  any  form  of  mercerising  the  tension  may  be  released  as  soon  as 
the  strong  caustic  soda  is  removed  from  the  cotton  by  washing;  it  is  not 
necessary  that  all  of  the  caustic  soda  should  be  removed  before  the  tension 
is  slackened. 

Attempts  have  also  been  made  to  mercerise  cotton  in  the  loose  state, 
as  in  the  form  of  combed  sliver.  Ingenious  devices  have  been  contrived 
to  prevent  the  fibers  from  shrinking  during  the  process.  In  one  form  of 
apparatus  the  sliver  is  packed  into  a  compact  mass,  and  the  mercerising 
solutions  are  forced  through  it  by  means  of  a  vacuum  or  a  pump.  In 
another  machine  the  sliver  is  placed  between  two  perforated  sheets  of 
metal  pressed  tightly  together,  and  then  exposed  to  the  successive  action 
of  caustic  soda  and  water.  A  centrifugal  perforated  drum  rotating  at  a 
high  speed  has  also  been  used  for  mercerising  cotton  sliver. 

Many  ingenious  machines  have  been  constructed  for  the  purpose  of 
mercerising  cotton  in  the  loose  state  or  in  the  form  of  combed  sliver,  but 
so  far  they  have  not  proved  of  any  practical  value.  An  illuminating 
article  on  this  subject  is  that  of  F.  Erban.^  It  has  been  suggested  by 
Gros  and  Bourcart  "*  to  twist  the  sliver  into  a  tight  thread,  in  which 
condition  it  is  mercerised,  washed  and  dried,  after  which  it  is  untwisted 

'  A  good  description  of  the  different  types  of  machines  for  mercerising  skein  yarn 
is  given  in  Herzfeld,  Das  Fdrbcn  urui  Bleichen,  vol.  II,  p.  373. 

2  This  centrifugal  mercerising  machine  was  devised  by  Kleincwefer,  and  was  once 
extensively  used.  We  understand,  however,  that  this  form  of  apparatus  has  now 
been  practically  abandoned  for  the  roller  type  of  machine. 

3  Monatsschnft.  Text.,  1907,  pp.  349  and  390. 

^  Ger.  Pat.  124,135;  see  Zeit.  Farb.  Ind.,  1902,  p.  54. 


620 


MERCERISED   COTTON 


METHODS  OF  MERCERISING 


621 


and  put  through  the  spinning  processes.  The  result,  however,  is  that 
owing  to  the  strong  twist  required  to  prevent  shrinkage,  only  the  outer 
layer  of  fibers  are  mercerised.  Bourcart  ^  also  attempts  the  mercerisa- 
tion  of  loose  cotton  in  a  somewhat  similar  manner  by  holding  the  fiber 
in  a  stretched  condition  between  endless  metal  fabrics.  Mather,  Hiibner 
and  Pope  ^  have  also  constructed  a  somewhat  similar  machine,  only  the 
caustic  soda  lye  is  injected  through  the  fiber  held  firmly  between  two 
sheets  of  perforated  metal.  Kleinewefer's  Sohne*^  constructed  a  centrif- 
ugal mercerising  machine  for  loose  cotton,  relying  on  the  centrifugal 
force  to  keep  the  fibers  in  a  sufficient  state  of  tension,  but  without  any 
marked  success.  Heberlein  and  Co.^  used  a  similar  apparatus  of  some- 
what different  construction.  Ahnert  ^  places  the  well  wet-out  cotton  in 
a  perforated  holder,  puts  on  a  high  pressure  and  attempts  mercerisation 
in  that  form,  reh'ing  on  the  immobility  of  the  fiber  to  prevent  shrinkage. 
Machines  have  also  been  constructed  to  mercerise  yarn  on  caps  and 
delicate  fabrics  and  wares  which  cannot  be  tightly  stretched.  None  of 
these  methods,  however,  have  been  successful. 

In  British  patents  175,741  and  175,761,  recently  issued  to  A.  Nelson, 
a  machine  for  mercerising  cotton  rovings  is  described.     The  roving  must 


Fig.  240. — Nelson  Machine  for  Mercerising  Cotton  Roving. 


be  especially  prepared  and  twisted  sufficiently  to  enable  it  to  stand  the 
tension.  The  general  structure  of  the  apparatus  may  be  seen  from  the 
accompanying  drawing  (Fig.  240)  which  shows  a  side  elevation  and  plan. 
The  method  of  operating  is  very  similar  to  the  common  form  of  warp 
mercerising  machine  so  largely  used  in  America.  The  rovings  are  passed 
through  the  various  processes  of  boiling-out,  mercerising,  washing,  drying 
and  sizing  in  the  form  of  continuous  chains  or  ropes.  Owing  to  the 
naturally  loose  structure  of  cotton  rovings  it  seems  difficult  to  understand 
how  sufficient  tension  can  be  placed  on  the  fiber  so  as  to  give  it  the  proper 


1  Ger.  Pat.  145,582;  see  Zeil.  Farb.  Ind.,  1904,  p.  48. 
"^Ger.  Pat.  177,166. 

6  Ger.  Pat.  209,428. 


^  Ger.  Pat.  181,927. 
*  Ger.  Pat.  204,512. 


622  MERCERISED  COTTON 

condition  for  good  mercerisation,  and  it  is  doubtful  if  cotton  rovings 
mercerised  by  this  method  will  yield  a  product  with  any  high  degree  of 
luster.  Also  from  the  fact  that  when  cotton  in  this  rather  loose  condition 
is  treated  with  strong  solutions  of  caustic  soda  the  mass  of  fibers  become 
pulpy  and  somew^hat  mucilaginous  in  character,  it  is  difficult  to  under- 
stand how  the  rope  of  roving  can  be  maintained  in  its  proper  form.  Unless 
the  finished  product  is  delivered  from  the  machine  in  a  form  suitable  for 
subsequent  processing  of  drawing  and  spinning,  it  cannot  be  seen  what 
advantage  is  gained  by  the  process.  It  is  verj^  likely  that  after  mercer- 
ising in  this  manner  the  cotton  rovings  would  have  to  be  carded  up  again 
and  reprocessed  before  the  fiber  would  be  in  a  fit  condition  for  spinning. 
There  have  been  other  forms  of  machines  proposed  for  mercerising  cotton 
rovings,  usually  depending  on  a  carrying  mechanism  of  slats  or  grids 
to  keep  the  rovings  in  a  fixed  position  while  being  treated  with  the  various 
liquors.  As  far  as  mercerising  in  the  sense  of  producing  a  fiber  with  a 
high  degree  of  luster  is  concerned,  none  of  these  methods  have  ever 
amounted  to  much  in  practice,  and  the  present  method  does  not  seem  to 
offer  any  better  hope  in  this  connection.  If  mercerisation  is  only  desired 
for  the  purpose  of  increasing  the  dyeing  quality  of  the  fiber  without  any 
reference  to  the  luster,  then  it  might  be  possible  that  some  of  these 
machines  for  processing  rovings  might  serve  the  purpose  required. 

Another  process  for  the  mercerising  of  loose  cotton  is  that  of  Lohman. 
The  cotton,  previously  packed  so  closely  that  it  cannot  shrink,  is 
treated  with  caustic  lye,  which  is  forced  through  it  by  atmospheric  pres- 
sure, a  vacuum  having  been  first  made  in  the  receptacle  in  which  the 
cotton  is  packed.  In  another  method  the  cotton  is  packed  tightly 
between  two  wire  gauze  fabrics,  in  which  state  it  is  carried  through  the 
mercerising  lye  and  the  rinsing  process.  Mercerising  in  a  centrifugal 
machine  has  also  been  adopted,  the  centrifugal  force  being  relied  upon 
to  stretch  the  fiber  sufficiently  to  prevent  shrinkage,  springs  being  pro- 
vided, which  press  the  cotton  against  the  sides  of  the  basket.  This  latter 
process  has  recently  been  improved  upon  according  to  a  patent  of  Heber- 
lein,  in  which  the  use  of  springs  is  avoided  by  waiting  until  the  centrif- 
ugal force  alone  has  pressed  the  goods  tightly  against  the  side  of  the 
basket  before  adding  the  caustic  soda ;  this  method  can  be  applied  to  cen- 
trifugals with  a  horizontal  or  vertical  axis.  The  basket  should  be  double 
in  the  former  case,  and  there  should  be  two  perforated  drums,  one  inside 
the  other.  The  fibers  should  be  placed  into  the  intermediate  space  and 
packed  there  as  uniformly  as  possible.  The  machine  must  be  kept  in 
motion  in  either  case  uninterruptedly  throughout  the  mercerisation  and 
the  subsequent  rinsing  processes.  The  speed  of  the  centrifugal  can 
hardly  be  too  great,  so  far  as  the  action  on  the  goods  is  concerned. 

This  method,  it  is  claimed,  has  the  great  advantage  that  it  is  appli- 


METHODS  OF  MERCERISING  623 

cable  to  yarn  and  fabrics  as  well  as  to  loose  cotton,  and  also  that  it  can 
be  adapted  to  the  treatment  of  other  vegetable  fibers,  such  as  linen,  jute, 
and  ramie;  these  latter  claims  may,  however,  be  disregarded.  The 
method  is  worthless  in  itself  for  those  fibers  which  lie  parallel  to  the  cir- 
cumference of  the  centrifugal  shell  exactly  as  much  as  fibers  mercerised 
in  a  state  of  rest,  no  matter  what  the  centrifugal  force.  In  addition,  the 
fibers  crossing  them  shrink,  because  they  are  pressed  against  them,  whilst 
if  the  goods  are  packed  in  a  thin  layer  felting,  an  undesirable  result  is  sure 
to  occur.  If  the  goods  are  thickly  packed,  it  is  scarcely  possible  for  the 
centrifugal  force  alone  to  secure  sufficient  penetration,  without  introducing 
the  lye  under  high  pressure. 

In  order  to  avoid  the  use  of  this  extra  pressure,  a  method  has  been 
patented  by  Carl  Ahnert,  of  Chemnitz,  in  which  a  specially  prepared  lye 
is  used,  which  is  said  not  only  to  penetrate  the  cotton  easily,  but  to  keep 
it  from  moving,  so  that  mercerisation,  rinsing,  souring,  and  the  second 
rinsing  are  all  carried  out  without  shifting  the  goods  or  altering  the  pres- 
sure. In  this  system,  the  cleaned  loose  cotton  is  first  wetted  out  in  hot 
water.  It  is  then  put  under  heavy  pressure  in  the  soaking  vessel,  between 
two  perforated  plates,  which  is  sufficient  to  prevent  all  motion  and  shrink- 
ing during  mercerisation.  The  cotton  is  packed  as  uniformly  as  possible, 
so  that  every  part  is  subjected  to  the  same  pressure.  To  secure  this 
result  the  cotton  is  placed  in  layers,  with  wire  netting  interposed.  The 
materials  are  then  submitted  in  turn  to  the  action  of  the  various  Hquids, 
the  mercerising  lye  and  wash-water  being  forced  through  them  by  the 
usual  means. 

Cotton  cloth  is  principally  mercerised  in  the  unbleached  condition. 
There  has  been  some  dispute  as  to  which  is  best:  to  mercerise  first  and 
bleach,  or  to  bleach  first  and  then  mercerise;  experience,  however,  appears 
to  favor  the  first  method.  In  the  bleaching  operations,  which  usually 
involve  a  rather  severe  treatment  of  the  cotton  first  with  moderately 
strong  alkalies,  and  subsequently  with  solutions  of  bleaching  powder, 
the  fiber  suffers  more  or  less  chemical  alteration,  so  that  in  the  mercerising 
process  it  can  no  longer  enter  into  proper  chemical  union  with  the  caustic 
soda  employed;  and  hence  complete  true  mercerisation  is  not  effected. 
Although  cotton  should  be  thoroughly  scoured  {"  boiled  out  ")  before 
being  mercerised,  it  is  best  not  to  use  alkalies  for  the  purpose,  but  to 
employ  Turkey-red  oil  (or  other  suitable  sulfated  oil)  or  soap.  If  bleach- 
ing is  carefully  conducted  after  mercerising,  the  injury  to  the  luster  of  the 
fiber  is  very  slight.  Mercerised  cotton  does  not  require  a  prolonged  boil- 
ing in  alkalies  previous  to  the  operation  of  bleaching  as  with  ordinary 
cotton. 

To  obtain  the  best  conditions  for  high  luster,  yarn  should  be  well 
"  gassed  "   (singed)  before  mercerising,  as  otherwise  the  external,  hairy 


624 


MERCERISED   COTTON 


B. 


m 


RECOVERY   OF   CAUSTIC   SODA   FROM   MERCERISING   LIQUORS     625 

fibers  remain  loose  and  cannot  be  subjected  to  tension.  As  a  result, 
these  fibers  shrink,  and,  remaining  without  luster  themselves,  hide  to  a 
certain  extent  the  lustered  surface  of  the  yarn.  Moreover,  caustic  soda 
has  a  felting  action  on  these  free  filaments,  and  felting  is  especially- 
detrimental  to  luster. 

Another  method  of  preparing  or  boiling-out  cotton  yarn  or  cloth  for 
mercerising  is  to  steep  in  a  warm  liquor  containing  a  malt  preparation, 
squeeze  out,  and  allow  to  lay  overnight.  The  malt  preparation  causes  a 
slight  fermentation  in  the  pectin  substances  of  the  fiber  which  changes 
them  to  soluble  compounds  and  thus  permits  of  their  easy  removal.  It 
also  tends  to  soften  the  fiber  so  it  is  more  easily  penetrated  by  the  caustic 
soda  solution  in  its  subsequent  treatment.  Some  mercerisers  also  adopt 
the  method  of  passing  the  yarn  through  a  boiling  dilute  solution  of  soda 
ash,  squeezing  out  excess  of  hquor,  and  then  allowing  to  stand  overnight 
piled  up  in  the  wet  state.  This  condition  also  induces  a  fermentation 
of  the  pectin  matters,  and  is  said  to  yield  a  somewhat  softer  j-arn  after 
mercerising. 

In  mercerising  cloth  the  action  taking  place  between  the  sizing 
materials  (always  present  to  a  greater  or  lesser  degree  in  cotton  cloth) 
and  the  caustic  alkali  is  sufficient  at  times  to  raise  the  temperature  con- 
siderably, which  may  result  in  a  deficient  luster.  In  such  cases  recourse 
must  be  had  to  artificial  cooling  by  addition  of  ice  or  a  current  of  cold 
water  in  order  to  prevent  an  undue  rise  in  temperature. 

When  mercerised  cotton  is  to  be  bleached,  it  is  best,  after  the  first 
rinsing,  to  remove  the  major  portion  of  the  caustic  soda  and  arrest  the 
mercerisation,  but  not  to  rinse  again  in  acidulated  water,  as  would  ordi- 
narily be  done  if  the  material  were  not  to  be  immediately  bleached.  The 
small  amount  of  caustic  soda  which  still  remains  in  the  cotton  acts  in  a 
beneficial  manner  in  bleaching. 

19.  Recovery  of  Caustic  Soda  from  Mercerising  Liquors. — As  the 
caustic  soda  taken  up  by  the  cotton  in  its  mercerisation  has  to  be  all 
removed  again  from  the  material  before  the  process  is  completed,  it  may 
readily  be  understood  that  a  large  proportion  of  the  caustic  soda  must  be 
wasted  in  the  wash  waters  unless  proper  means  be  adopted  for  its  recovery 
and  purification.  In  the  economical  operation  of  the  mercerising  process 
it  becomes  necessary  to  recover  efficiently  the  caustic  soda  from  the  waste 
wash  waters.  This  requires  a  concentration  of  these  wash  waters,  and  a 
purification  of  the  lye  so  that  it  may  be  suitable  to  use  over  again.^ 

^  For  description  of  methods  for  recovery  of  caustic  soda  in  mercerising  liquors, 
see  Zeit.  Farb.  I  ml.,  1910,  p.  157.  Also  refer  to  O.  Ventner,  Ger.  Pat.  211,566;  Krais 
and  Petzold,  Ger.  Pat.  216,622;  Krais,  Brit.  Pat.  15,352  of  1907  and  Fr.  Pat.  379,992; 
also  Zeit.  Farb.  Ind.,  1909,  p.  107;  Wallach,  Ger.  Pat.  202,789;  Haubold,  Ger.  Pat. 
205,962,  and  212,900;  Moller-Holtkamp,  Ger.  Pat.  207,813. 


626 


MERCERISED   COTTON 


When  arrangement  is  made  for  the  recovery  of  the  caustic  soda  it  is 
best  to  use  the  wash  waters  in  such  a  manner  that  when  the  material  first 
emerges  from  the  mercerising  Hquor,  and  is  consequently  heavily  saturated 
with  caustic  soda,  it  is  washed  by  water  already  containing  some  caustic 
soda  derived  from  previous  washing.  That  is  to  say,  the  mercerised 
goods  are  run  in  the  opposite  direction  to  the  flow  of  the  wash  water 
through  a  series  of  tanks,  so  that  the  final  washing  is  with  fresh  water. 
This  allows  of  the  wash  water  in  its  final  use  to  be  rather  well  concen- 
trated, and  consequently  it  can  be  more  economically  evaporated.^  In 
order  to  recover  economically  the  waste  caustic  soda  from  the  mercerised 
goods  it  is  necessary  to  obtain  the  waste  liquor  at  as  high  a  degree  of  con- 


FiG.  242. — Steamer  for  Recovery  of  Caustic  Soda.     (Matter  System.) 


centration  as  possible.  In  the  usual  washing  operation  as  generally 
employed  after  mercerising,  the  waste  liquors  are  so  dilute  that  it  is  a 
question  as  to  whether  it  would  pay  to  purify  and  evaporate  them. 

The  wash  waters  become  contaminated  of  course  with  more  or  less 
foreign  matter  and  color  and  size  from  the  goods,  and  there  is  also  formed 
a  good  proportion  of  sodium  carbonate  by  reason  of  the  exposure  of  the 
caustic  soda  solution  to  the  air.  The  purification  and  recaustification 
of  these  liquors  are  carried  out  by  mixing  in  a  tank  with  a  suitable  pro- 
portion of  slaked  lime  and  allowing  the  sludge  to  settle.  The  clear  puri- 
fied liquor  is  drawn  off  and  evaporated  in  suitable  vacuum  evaporators 
until  concentrated  to  the  proper  degree  for  being  again  available  for  use 
(about  50°  Tw.). 

1  See  Scott  &  Co.,  Bril.  Pat.  19,734  of  1902. 


RECOVERY  OF  CAUSTIC  SODA  FROM   MERCERISING  LIQUORS     627 

Recently  it  has  been  found  that  in  the  mercerising  of  piece  goods  a 
very  economical  and  effective  method  of  washing  is  by  the  use  of  steam 
instead  of  water.^  This  removes  the  caustic  soda  from  the  cloth  much 
quicker  and  gives  a  wash  water  of  a  comparatively  high  concentration 
(14°-16°  Tw.),  so  that  the  cost  of  subsequent  evaporation  is  low.  By 
this  method  of  recovery  from  96-98  percent  of  the  caustic  soda  may  be 
regained. 

In  the  Bemberg  or  Matter  process  ^  a  special  steaming  apparatus 
shown  in  Figs.  242  and  243  is  employed,  also  a  concentrating  apparatus 
shown  in  Fig.  244.     The  course  of  the  material  through  the  chamber  is 


Fig.  243. — Diagram  of  Matter  Steamer  for  Washing  Mercerised  Cloth. 


shown  in  Fig.  243.  (A)  represents  a  chamber  on  the  floor  of  which  is 
arranged  a  vat  (B),  subdivided  into  a  number  of  separate  compartments 
(C)  by  the  partitions  (D)  and  (E)  which  are  so  arranged  that  a  fluid  is  able 
to  flow  downwards  from  the  topmost  compartment  (C^)  to  the  bottom. 
In  the  compartment  (C)  are  arranged  the  rollers  (F),  and  in  the  upper  part 
of  the  chamber  another  series  of  rollers  (G)  is  arranged,  actuated  by  the 
wheels  (H),  which  are  in  turn  driven  by  the  belt  (K)  from  the  pulley 
(J)  to  the  pulley  (M).     In  the  chamber  (A)  vertical  partitions  (L,  A^) 

1  See  Matter,  Ger.  Pat.  215,045  of  1908;  also  Petzold,  Brit.  Pat.  20,656  of  1911. 

2  See  Ger.  Pat.  215,045  and  Brit.  Pat.  20,656  of  1911. 


628 


MERCERISED   COTTON 


are  arranged,  which  partitions  dip  into  the  liquid  in  the  vat  (B),  while 
they  also  carry  channels  (0)  filled  with  liquid,  into  which  drops  a  cover 
(P),  so  that  by  this  hydraulic  joint  an  airtight  space  is  obtained  inside 
the  chamber  (A). 

The  material  (Q)  coming  from  the  mercerising  machine  is  carried  over 
a  cylinder  (R)  into  the  lowest  compartment  (C),  then  upwards  over  the 
rollers  ((7),  downwards  into  the  next  compartment  (C),  and  so  on  in  a 
zigzag  course  until  the  material  passes  out  of  the  chamber  (A)  between 


Fig.  244. — Evaporator  for  Matter  System  of  Caustic  Soda  Recovery. 


the  squeezing  rolls  (S,  T)  ready  to  be  taken  where  required  for  further 
treatment.  The  removal  of  the  lye  from  the  material  takes  place  inside 
the  airtight  chamber,  and  for  this  purpose  pipes  ( IJ)  and  rods  ( V)  are 
fitted  across  the  chamber  in  such  a  position  that  the  material  is  stretched 
between  them.  The  pipes  ( JJ)  are  perforated  on  the  side  towards  the 
material,  and  steam  is  led  into  the  pipes,  passing  out  through  the  holes 
and  acting  on  the  material  carried  past  in  such  a  manner  that  the  lye  is 
removed  from  the  cloth.     The  rod  (F)  serves  to  strip  off  the  lye  collected 


PROPERTIES   OF   MERCERISED    COTTON 


629 


on  the  surface  of  the  material  by  the  blast  action  of  the  pipe  (  U),  so  that 
it  falls  down  into  the  compartments  (C).  The  process  is  repeated  until 
the  material  finally  passes  out  almost  free  from  lye,  through  the  rolls 
{S  and  T),  but  before  reaching  the  latter  the  material  is  subjected  to  a 
powerful  water  spray  which  is  supplied  through  a  pipe  (Z).  This  water 
flows  into  the  compartment  (C^),  and  mixes  therein  with  the  lye.  This 
mixed  liquid  flows  into  the  next  lower  compartment,  which  in  turn  sup- 
plies the  one  lower  still,  and  so  on.  It  will  at  once  be  seen  that  each 
succeeding  lower  compartment  commencing  from  (C^)  contains  stronger 
lye,  the  concentration  of  the  series  being  regulated  by  the  amount  of 
water  passing  through  the  pipe  (Z).     This  confers  the  important  advan- 


FiG.  245. — Steamer  for  Caustic  Soda  Recovery.     (Krais  System.) 

tage  that  lye  can  be  drawn  off  for  direct  use  from  each  compartment  with- 
out its  having  to  be  regenerated. 

20.  Properties  of  Mercerised  Cotton. — Apart  from  its  high  luster  and 
somewhat  increased  tensile  strength,  mercerised  cotton  exhibits  but  few 
apparent  differences  from  the  ordinary  fiber.  Toward  dyestuffs  and 
mordants  it  is  rather  more  reactive  and  consequently  will  dye  deeper 
shades  with  the  same  amount  of  dyestuff  than  ordinary  cotton;  this 
property  is  rather  to  be  ascribed  to  the  increased  absorptivity  of  the  fiber 
than  as  the  result  of  any  chemical  modification  of  the  cellulose  composing 
it;  it  is  also  independent  of  the  method  of  mercerising,  that  is,  whether 
accompanied  by  tension  or  not. 

Haller  ^  has  advanced  the  theory  that  the  increased  affinity  of  mer- 
cerised cotton  for  dyes  is  due  to  the  removal  of  the  cuticle  from  the  fiber 
1  Zdt.  Farb.  hid.,  1907,  p.  125. 


630 


MERCERISED  COTTON 


in  mercerising,  it  being  presumed  that  this  cuticle  or  tough  skin  tends  to 
resist  the  free  transfusion  of  sohitions  of  dyes  and  mordants  into  the  fiber. 
This  view,  however,  is  opposed  by  Herzog,  who  shows  that  the  cuticle  of 
both  the  raw  and  mercerised  cotton  fiber  is  approximately  the  same  in 
both  chemical  and  physical  properties,  and  concludes  that  the  increased 
reactivity  is  caused  by  the  hydration  of  the  cellulose  and  changed  physical 
structure  of  the  cell-wall.  Justin-Mueller  ^  takes  the  view  that  mercerised 
cotton  through  the  treatment  with  caustic  soda  acquires  a  gelatinous 
condition  and  becomes  more  absorptive.  Dreaper  considers  the  more 
highly  developed  colloidal  nature  of  mercerised  cotton  the  cause  of  its 
greater  reactivity  with  dyestuffs. 

Wichelhaus  and  Vieweg  have  studied  the  action  between  mercerised 
cotton  and  certain  metallic  oxides,  and  found  it  to  absorb  3.82  percent  of 
barium  hydrate  from  a  ^  normal  solution,  and  2.18  percent  of  strontium 
hydrate  from  a  yV  normal  solution. 

Mercerised  cotton  exhibits  greater  chemical  activity  than  ordinary 

cotton.  In  pre 
paring  artificial 
silk  and  other 
plastic  cellulose 
materials  using 
viscose,  cupram- 
monium  cellu- 
lose, or  cellulose 
acetate  solutions, 
it  is  nearl}'  al- 
ways the  prac- 
tice to  start  with 
mercerised  cellu- 
lose, as  this  dis- 
solves much  better  in  the  required  reagents  than  ordinary  cellulose. 

The  increased  affinity  of  mercerised  cotton  for  substantive  dyes  is  a 
very  characteristic  property.  Mercerised  cotton  requires  from  20  to  50 
percent  less  coloring  matter  than  ordinary  cotton  for  the  production  of 
the  same  intensity  of  color. 

SchaposchnikofT  and  Minajeff-  have  investigated  quantitatively  the 
difference  in  dyestuff  absorption  between  ordinary  and  mercerised  cotton. 
With  indigo,  substantive  dyes,  tannin  dyes  (basic),  and  sulfur  dyes,  the 
mercerised  cotton  takes  up  about  40  percent  more;  with  developed  dyes, 
however,  the  difference  is  only  4  to  10  percent.     In  padding  with  aniline 

1  Bull.  Soc.  Ind.  Rouen,  1905,  p.  35. 

'-Zeit.  Farb  Ind.,  1903,  p.  257;  1904,  p.  163;  1905,  p.  81;  1907,  pp.  233,  252,  309, 
and  345. 


Fig.  246. — Triple  Effect  Evaporator  for  Caustic  Soda  Recovery. 
(Krais  System.) 


PROPERTIES   OF   MERCERISED   COTTON 


631 


salt  the  mercerised  fiber  takes  up  somewhat  less,  but  in  spite  of  this  the 
color  is  darker.  In  the  case  of  mordant  salts  contradictory  results  are 
obtained;  some  are  absorbed  better  and  some  not  so  well  by  the  mer- 
cerised cotton.  In  the  dyeing  of  Turkey  Red  there  is  practically  no 
difference  to  be  observed  between  the  two  cottons;  but  on  the  contrary, 
mercerised  cotton  dyes  more  readily  with  the  mineral  colors  (Manganese 
Brown  about  12.5  percent  and  Iron  Buff,  40  percent). 

Knecht  ^  has  made  comparative  tests  with  various  mercerised  and  un- 
mercerised  samples  of  cotton  in  order  to  determine  the  quantity  of  coloring 
matter  fixed  in  each  case.  The  dyestuff  employed  was  Benzopurpurine 
4B,  and  the  amount  of  dyestuff  fixed  was  determined  by  the  titanous 
chloride  method.     A  summary  of  his  results  are  given  in  the  following  table : 


Dyestuflf  Fixed 

by  100  Grams. 

Nature  of  Cotton  Dved. 

of  Cotton. 

0.69 

Ordii 

ary  cotton  not  boiled  out. 

2.78 

Cotton  mercerised  with  NaOH,  33°  Be. 

5.23 

treated  with  HNO3  of  43°  Be. 

1.55 

boiled  out,  not  mercerised. 

2.90 

"          mercerised  with  tension  with  NaOH  of  29°  Be. 

3.39 

without  tension  with  NaOH  at  29°  Be. 

1.50 

bleached,  not  mercerised. 

2.86 

"         mercerised  with  tension  at  29°  Be. 

3.54 

without  tension  at  29°  Be. 

The  next  table  gives  the  results  using  Egyptian  cotton  under  varying 
conditions  of  mercerising: 


Dvestuff  Fixed 

by  100  Grams      Concentration  c 

)f  Caustic  Soda  Solution. 

of  Cotton. 

1 .  77                            Unmer 

jerised  cotton. 

1 .  88                           Mercer 

ised  at  10°  Be. 

2.39 

14°  Be. 

2.57 

'            16°  Be. 

2.95 

'            19°  Be. 

3.02 

21.5°  Be. 

3.15 

'            24°  Be. 

3.27 

'            26.5°  Be. 

3.38 

*            29°  Be. 

3.50 

31°  Be. 

3.56 

33°  Be. 

3.60 

.35.5°  Be. 

3.66 

.37.5°  Be. 

1  Jour.  Soc.  Dyers  &  Col,  1908,  p.  68. 


632 


MERCERISED  COTTON 


The  last  table  shows  that  the  affinity  of  cotton  for  direct  dyestuffs 
increases  in  proportion  to  the  degree  of  mercerisation ;  consequently,  the 
degree  of  mercerisation  may  be  ascertained  by  the  quantity  of  Benzopur- 
purine  fixed  by  100  grams  of  cotton. 

Hiibner  and  Pope  ^  have  studied  the  dyeing  properties  of  mercerised 
cotton  as  compared  with  ordinary  cotton  and  have  shown  that  the  increase 
in  the  absorption  of  dyestuff  is  dependent  on  the  degree  of  mercerisation. 
Their  results  are  stated  as  follows : 

(1)  Cold  caustic  soda  solution  of  1°  Tw.  has  a  considerable  effect  in  increasing  the 
affinity  of  cotton  for  substantive  dyes,  and  from  0°  to  18°  Tw.  the  increase  in  affinity 
for  the  dyestuff  is  roughly  jjroportional  to  the  concentration  of  the  caustic  soda. 
Though  dilute  solutions  of  caustic  soda  in  the  cold  have  the  effect  of  increasing  the 
dyeing  power  of  cotton,  such  solutions  used  hot  have  no  such  effect.  Cotton  yarn 
boiled  with  caustic  soda  solution  of  2°  Tw.  has  the  same  affinity  for  dyestuffs  as 
untreated  cotton. 

(2)  Between  18°  and  22°  Tw.  the  increase  in  the  concentration  of  the  soda  has 
a  greater  effect  in  increasing  the  affinity  of  the  cotton  for  the  color  than  corresponding 
increases  of  lower  concentrations.  With  soda  of  22°  to  26°  Tw.  the  effect  becomes 
still  greater,  and  from  2G°  to  30°  Tw.  the  increased  affinity  is  still  much  greater. 

(3)  Above  30°  Tw.,  however,  an  increase  in  the  strength  of  the  caustic  soda  solution 
has  less  effect  in  increasing  the  affinity  for  dyes.  Between  55°  and  70°  Tw.  the 
increase  in  affinity  is  very  slight. 

(4)  When  mercerised  ■with  caustic  soda  solutions  above  70°  Tw.  there  is  a  decrease 
in  the  affinity,  so  that  cotton  mercerised  with  caustic  soda  of  80°  Tw.  shows  the  same 
dyeing  power  as  that  mercerised  at  35°  Tw. 

Hiibner  and  Pope  have  also  studied  the  degree  of  contraction  in  cotton 
yarn  caused  by  treatment  with  caustic  soda  solutions  of  different  strengths. 
The  following  table  shows  the  results  of  their  tests: 


Strength  of 

NaOH, 

°Tw. 

Length  of 
Hank, 
Yards. 

Contraction, 
Percent. 

Strength  of 
NaOH, 
°Tw. 

Length  of 
Hank, 
Yards. 

Contraction, 
Percent. 



200 

— 

20 

186.8 

6.6 

0  (water) 

198 

1.0 

22 

171.3 

14.3 

1 

196.4 

1.7 

24 

163 . 1 

18.4 

2 

195.7 

2.1 

26 

160.3 

19.8 

3 

195.6 

2.2 

28 

160.0 

20.0 

4 

195.5 

2.2 

30 

158.2 

20.9 

5 

195.2 

2.4 

35 

150.2 

24.9 

6 

194.2 

2.9 

40 

143.7 

28.1 

7 

193.7 

3.1 

45 

141.0 

29.5 

8 

194.2 

2.9 

50 

154.2 

28.9 

9 

194.0 

3.0 

55 

142 . 7 

28.6 

10 

194.2 

2.9 

60 

145.3 

27.3 

12 

194.5 

2.7 

65 

149.2 

25.4 

14 

192.7 

3.6 

70 

150.3 

24.8 

16 

190.4 

4.8 

75 

152.8 

23.6 

18 

188.7 

5.6 

80 

154.2 

22.9 

1  Jour.  Soc.  Chcm.  Ind.,  1909,  p.  404. 


TESTS   FOR   MERCERISED   COTTON  633 

It  will  be  noticed  that  at  about  20°  Tw.  there  is  a  sudden  increase  in  the 
amount  of  contraction,  and  that  a  maximum  is  reached  at  about  45°  Tw. 

Mercerised  yarn  has  the  disagreeable  property  that  it  sometimes  gives 
streaky  and  uneven  dyeings.  The  cause  of  this  is  often  quite  unknown, 
and  the  unevenness  often  disappears  in  the  next  batch  as  mj^steriously  as 
it  came  in  the  one  before.  There  must,  of  course,  be  something  wrong 
either  in  the  mercerisation  or  in  the  dyeing.  Dyers  who  mercerise  their 
own  yarn  are  best  able  to  investigate  the  matter,  but  many  dyers  are 
called  upon  to  dye  yarns  mercerised  by  others.  When  uneven  dyeing 
manifests  itself,  the  only  possible  course  is  to  dye  with  the  same  yarns  a 
small  batch  of  other  yarn  known  to  be  perfectly  and  uniformly  mercerised, 
and  a  stock  of  such  yarn  should  always  be  at  hand.  If,  in  the  same  bath, 
all  the  yarns  dye  badly,  the  fault  is  in  the  dyeing;  or  in  both  dyeing  and 
mercerising,  if  the  perfectly  mercerised  yarn,  although  defective,  is  much 
better  than  the  yarn  of  unknown  character.  It  is  very  difhcult  to  rectify 
unequally  mercerised  yarn.  A  second  mercerisation  is  worse  than  useless, 
for  then  those  parts  which  were  over-mercerised  in  the  first  operation 
become  still  more  over-mercerised,  for  they  have  more  affinity  for  the 
caustic  lye  than  the  parts  less  mercerised  at  first.  Bleaching  is  utterly 
useless,  unless  the  uneven  mercerisation  is  detected  before  dyeing.  In 
this  case  a  soaking  in  weak,  warm  methylated  spirit,  followed  by  an 
ordinary  permanganate  bleach,  wMl  be  effective  in  many  cases. 

It  has  also  been  found  that  the  uneven  dyeing  of  mercerised  yarns 
may  often  be  prevented  by  treating  the  mercerised  cotton  before  dyeing 
with  a  solution  of  caustic  soda  of  about  25°  Tw.  and  then  washing  thor- 
oughly. The  fact  that  mercerised  yarns  from  different  mercerising  plants 
will  nearly  always  dye  somewhat  differently  is  well  known.  In  many 
cases  it  is  not  possible  to  run  the  mercerised  cotton  of  one  mill  along  with 
that  of  another  if  the  fabric  so  made  is  to  be  dyed.  This  difference  in 
coloring  is  probably  due  to  the  fact  that  one  merceriser  may  give  the 
yarn  a  much  longer  treatment  in  the  caustic  soda  bath  than  the  other. 
It  may  also  be  caused  by  the  use  of  different  qualities  of  water  in  the 
mercerising  process,  or  in  the  use  of  different  methods  of  washing  and 
softening. 

21.  Tests  for  Mercerised  Cotton. — With  a  solution  of  iodine  in  potas- 
sium iodide  mercerised  cotton  exhibits  a  reaction  which  serves  to  distin- 
guish it  from  ordinary  cotton.  By  immersing  samples  of  ordinary  and 
mercerised  cotton  for  a  few  seconds  in  a  solution  of  20  grams  of  iodine 
in  100  cc.  of  a  saturated  solution  of  potassium  iodide,  then  washing  with 
water,  the  ordinary  cotton  becomes  pale  brown  while  the  mercerised  cotton 
remains  black.  On  continuing  the  washing  the  ordinary  cotton  finally 
becomes  colorless,  while  the  mercerised  sample  remains  a  bluish  black, 
which  fades  only  very  slowly. 


634 


MERCERISED   COTTON 


On  treatment  of  cotton  with  a  1/100  normal  solution  of  iodine,  and 
exposing  the  sample  to  the  air,  ordinary  cotton  becomes  nearly  decolorised 
in  a  very  short  time,  while  mercerised  cotton  will  exhibit  a  gradation  of 
color  corresponding  to  the  strength  of  caustic  soda  used  in  mercerising. 
It  also  appears  that  cotton  mercerised  without  tension  has  a  greater 
a,bsorptive  power  for  iodine  than  cotton  stretched  during  the  merceri- 
sation. 

Another  reagent  for  mercerised  cotton  is  a  solution  of  46  grams  of 
aluminium  chloride  in  100  cc.  of  water  to  which  is  added  15  to  20  drops  of 
iodine  solution.  On  steeping  mercerised  cotton  in  this  solution  for  one  hour 
it  gives  a  dark  chocolate-brown  color,  while  ordinary  cotton  remains 
colorless.' 

By  using  a  solution  containing  280  grams  of  zinc  chloride  in  300  cc. 
of  water,  to  100  cc.  of  which  are  added  20  drops  of  a  solution  of  1  gram 
of  iodine  and  20  grams  of  potassium  iodide  in  100  cc.  of  water,  more  dis- 
tinctive colorations  between  ordinary  and  mercerised  cotton  can  be 
obtained  than  is  the  case  even  with  the  above  described  solution  of 
iodine.^  The  color  given  by  this  reagent  on  ordinary  cotton  is  more 
readily  removed,  while  the  color  left  on  the  mercerised  cotton  is  more 
persistent.  By  use  of  this  solution  the  strength  of  caustic  soda  solution 
employed  in  the  mercerisation  of  a  sample  may  be  determined. 

Hiibner  {Jour  Chem.  Soc,  1908,  p.  105)  gives  a  table  of  tests  showing 
the  reaction  of  this  reagent  on  cotton  samples,  mercerised  with  different 
strengths  of  caustic  soda: 


Strength  of 

I. 

II. 

III. 

Caustic  Soda, 

20  Drops  of  Iodine 

10  Drops  of  Iodine 

5  Drops  of  Iodine 

°Tw. 

Solution. 

Solution. 

Solution . 

0 

Slight  red  tint 

Remains  white 

Colorless 

10 

Faint  red 

Very  faint  brown 

( ( 

20 

Dark  chocolate 

Darker  brown 

1  ( 

23 

Darker,  bluer 

Darker,  bluer 

1 1 

26 

Much  darker  and  bluer 

Much  darker  and  bluer 

( 1 

30 

Very  dark  navy  blue 

Darker,  reddish  blue 

Faint  blue 

40 

Black 

Much  darker 

Bluer 

50 

Black 

Darker  than  40 

Darker  blue 

60 

Black 

Darker  than  40 

Slightly  lighter 

70 

Black 

Darker  than  40 

Lighter 

iHubner,  Jo^lr.  Soc.  Chem.  Ind.,  1908,  p.  110. 

*  See  Lange  (Fdrb.  Zeit.,  1903,  p.  369).  The  sample  should  be  left  in  the  reagent 
for  three  minutes  and  then  washed;  the  color  is  quickly  removed  from  ordinary  cotton, 
while  the  mercerised  cotton  remains  blue  for  some  time. 


TESTS  FOR   MERCERISED  COTTON  635 

The  different  proportions  of  the  iodine  solution  were  added  to  100  cc. 
of  the  zinc  chloride  solution.  When  woven  fabrics  are  examined,  the 
sample  should  be  first  dipped  in  water  and  pressed  between  filter  paper 
before  applying  the  reagent.  Preliminary  removal  of  dyestuffs  does  not 
interfere  with  the  test. 

Another  characteristic  test  for  mercerised  cotton  is  its  behavior  with 
Benzopurpurine.^  If  ordinary  cotton  and  mercerised  cotton  be  dyed  with 
Benzopurpurine  in  a  dilute  dyebath,  then  hydrochloric  acid  added  drop 
by  drop  until  the  ordinary  cotton  is  just  changed  to  a  blue  color,  the 
mercerised  cotton  will  still  remain  a  bright  red.-  This  test  was  first  pro- 
posed by  Knecht,  who  conducted  it  so  that  sufficient  hydrochloric  acid 
was  added  to  change  both  samples  to  a  blue  color.  Then  a  solution  of 
titanous  chloride  was  added  cautiously  to  the  liquid  until  just  before 
decolorisation  when  the  sample  of  ordinary  cotton  remained  blue  while 
that  of  the  mercerised  cotton  became  red.^ 

Knaggs  ^  conducts  the  same  test  by  using  a  very  dilute  solution  of 
Benzopurpurine  4B,  5  cc.  of  the  dye  solution  (0.1  gram  per  liter)  to  100  cc. 
of  water  being  employed  and  acidifying  the  boiling  liquid  with  adding 
titanous  chloride.  Cotton  will  be  colored  blue-black  while  mercerised 
cotton  will  dye  red. 

David  ^  tests  the  difference  between  mercerised  and  non-mercerised 
cotton  as  follows:  The  yarn  or  fabric  is  boiled-out  and  as  much  of  its 
color  removed  as  possible;  it  is  then  spotted  in  a  stretched  condition  with 
caustic  soda  liquor  of  40°  Be.,  and  further  with  the  same  liquor  diluted 
with  water  1  :  1  and  1:3.  The  sample  thus  prepared  is  then  dyed  with 
Congo  Red;  if  the  cotton  was  previously  non-mercerised  the  spotted 
places  will  dye  up  darker,  but  if  the  sample  had  been  mercerised  the  color 
will  be  uniform  all  over. 

Higgins  ^  has  shown  that  mercerised  cotton  is  more  hygroscopic  than 
ordinary  cotton,  and,  furthermore,  the  proportion  of  moisture  absorbed 
increases  with  the  "  degree  of  mercerisation,"  as  shown  by  the  following 
table : 

^  In  carrying  out  this  test  care  must  be  had  to  use  only  pure  Benzopurpurine,  as 
the  presence  of  Safranine  or  other  compoimds  usually  present  in  commercial  samples 
of  Benzopurpurine  may  vitiate  the  delicacy  of  the  test. 

2  KJnaggs,  Jour.  Soc.  Dyers  &  Col.,  1908,  p.  112.  The  fact  that  the  mercerised 
cotton  remains  red  is  evidently  not  due  to  any  residual  alkaU  in  the  fiber,  for  if  suffi- 
cient acid  is  added  to  turn  the  color  of  the  mercerised  sample  to  a  blue,  and  this  sample 
is  immersed  again  in  the  dye  solution,  the  red  color  reappears. 

3  See  Jour.  Soc.  Dyers  &  Col,  1908,  p.  67. 
*  Jour.  Soc.  Dyers  &  Col,  1908,  p.  112. 

5  Rev.  Gen.  Mat.  Col,  1907,  p.  261. 
'■  Jour.  Soc.  Chem.  Ind.,  1909,  p.  188. 


636 


MERCERISED  COTTON 


Degree  of  Mercerisation. 

Moisture, 
Percent. 

Ordinarj'^  cotton 

G.20 

Mercerised  with  caustic  soda  10°  Tw 

20°  Tw 

6.37 
6.68 

"                "                30°  Tw 

8.40 

"                 "                40°  Tw 

9.41 

50°  Tw 

"                "                60°  Tw 

"                "               70°  Tw... .             

9.43 
9.57 
9.69 

In  these  tests  cotton  yarn  was  well  boiled  out  and  mercerised  without 
tension  with  caustic  soda  solutions  of  different  strengths.  The  samples 
were  then  washed,  soured,  washed,  dried  at  60°  C,  and  then  exposed  to 
the  air  for  some  time.  The  moisture  was  determined  by  weighing  before 
and  after  drying  for  eight  hours  at  100°  C. 

If  these  results  are  compared  it  will  be  noticed  that  a  sharp  increase 
is  evident  between  cotton  mercerised  at  20°  Tw.  and  30°  Tw.,  while  beyond 
40°  Tw.  the  moisture  becomes  practically  constant. 

Oxley  ^  states  that  mercerised  cotton  does  not  dye  to  as  full  a  shade 
after  drying  as  when  dyed  after  mercerising  but  before  drying.  It  has  also 
been  found  that  ordinary  cotton  behaves  in  the  same  manner.  It  is  also 
known  that  cotton  cloth  which  has  been  thoroughly  dried,  even  after  a 
long  exposure  to  the  atmosphere,  will  not  absorb  the  amount  of  moisture 
it  originall}^  contained  in  the  air-dry  state.^ 

David  gives  a  method  for  distinguishing  mercerised  cotton,  based  on 
the  fact  that  cotton  if  mercerised  a  second  time  acquires  no  increased 
affinity  for  the  dyestuff.  The  cloth  to  be  treated,  if  colored,  is  first  stripped 
of  the  color  by  treatment  in  hydrochloric  acid,  and  stretched  on  a  frame. 
Three  solutions  of  caustic  soda  are  then  prepared:  (1)  Standing  40°  Be.; 
(2)  40°  Be.  diluted  with  an  equal  quantity  of  water;  (3)  40°  Be.  diluted 
with  three  times  the  quantity  of  water.  These  three  solutions  are  dropped 
on  different  parts  of  the  cloth  on  the  frame.  After  a  short  time  the  frame 
and  cloth  are  rinsed  in  water  to  remove  the  caustic,  then  scoured  with 
sulfuric  acid,  and  again  rinsed.  The  cloth  is  then  colored  with  Congo  Red. 
If  the  cotton  before  treatment  was  unmercerised,  the  spots  on  which  the 
caustic  solutions  were  dropped  are  of  a  more  intense  color  than  the  other 
parts  of  the  piece,  while  mercerised  cotton  shows  no  difference  in  color. 

22.  Ultramicroscopic  Appearance  of  Mercerised  Cotton. — Microscopic 
examination  in  polarised  light  affords  a  means  of  distinguishing  between 

1  Jour.  Soc.  Dyers  &  Col,  1906. 

2  Higgins,  Jour.  Soc.  Chem.  Ind.,  1909,  p.  188. 


CELLULOSE  HYDRATE;    HYDRACELLULOSE  637 

mercerised  and  unmercerised  cotton  fibers.  The  corrugated  strain  lines 
showing  strong  illumination  are  distinctly  seen  in  unmercerised  cotton, 
are  diffused  in  cotton  mercerised  without  tension  and  entirely  missing  in 
cotton  mercerised  with  tension.  From  ultramicroscopic  investigations 
on  mercerised  cotton  fibers  Harrison  ^  comes  to  the  conclusion  that  the 
swelling  of  cotton  by  treatment  with  caustic  soda  solution  is  analogous 
to  the  swelling  of  gelatine  by  water,  and  is  caused  not  by  a  chemical  action 
on  the  cellulose  molecule  itself,  but  by  a  dispersion  of  a  colloidal  complex 
of  cellulose  representing  the  fiber.  The  degree  of  dispersion  is  greater 
when  mercerised  without  tension  than  with  tension.  Mercerised  cotton, 
therefore,  is  nothing  more  than  ordinary  cotton  with  its  cellulose  complex 
in  a  more  highly  dispersed  condition. 

23.  Cellulose  Hydrate;  Hydracellulose. — As  previously  mentioned 
mercerised  cotton  is  considered  to  be  an  alteration  product  of  cellulose 
known  as  cellulose  hydrate  or  hydracellulose.  The  cellulose  is  supposed 
to  have  united  with  a  molecule  of  water  giving  C2Hio05-H20.  Hydra- 
cellulose is  not  to  be  confused  with  hydrocellulose,  as  in  the  latter  a  distinct 
rearrangement  in  the  molecule  takes  place,  the  cellulose  being  hydrolysed. 
The  form  of  combination  of  the  water  in  the  case  of  hydracellulose,  on  the 
other  hand,  is  probably  similar  to  that  in  various  crystalline  salts,  contain- 
ing water  of  hydration  (or  crystallisation).  The  researches  of  Ost  and 
Westhoff  -  on  "  cellulose  hydrates  "  (including  mercerised  cotton)  indicate 
that  when  these  substances  are  freed  from  all  traces  of  hygroscopic  moisture 
they  have  the  same  composition  as  ordinary  cellulose,  i.e.,  CeHioOs. 
Hydrocelluloses,  on  the  other  hand,  appear  to  contain  chemically  combined 
water. 

Hydracellulose  has  the  property  of  absorbing  a  greater  proportion 
of  alkali  from  dilute  caustic  soda  solutions  than  non-hydrated  cotton,  as 
shown  by  the  following  table,  using  a  2  percent  solution  of  caustic  soda: 

Character  of  Cotton.  NaOH  Absorbed, 

Ordinary  purified  cotton 1 

Cotton  mercerised  in    8  percent  NaOH 1.4 

"16  percent  NaOH 2.8 

Hydracellulose  of  viscose  silk 4.5 

"  "  cuprate  silk 4.0 

The  amount  of  alkali  absorbed  by  hydracellulose  does  not  increase 
beyond  2.8  percent  even  if  the  concentration  of  the  mercerising  bath  is 
above  16  percent  NaOH.  It  also  seems  to  be  independent  of  the  tempera- 
ture of  the  solution. 

Attention  may  also  be  called  to  the  manner  in  which  different  hydra- 
celluloses  behave  with  caustic  soda  solutions  of  high  concentration.     It 

1  Jour.  Soc.  Dyers  d-  Col,  1915,  p.  200. 

2  Chem.  Zeit.,  1909,  p.  197. 


638 


MERCERISED   COTTON 


is  known  that  the  viscose  and  cuprate  artificial  silks  belong  to  the  same 
general  class  of  hydracelluloses  as  mercerised  cotton.  In  fact,  they  are 
scarcely  to  be  distinguished  in  their  reducing  properties.  Between 
these  artificial  silks,  however,  and  mercerised  cotton,  there  apparently 
exists  a  marked  contrast  as  to  the  degree  of  hydration.  The  former  when 
treated  with  strong  caustic  soda  solutions  and  washed  with  water,  become 
gelatinous  and  almost  completely  dissolve.  Mercerised  cotton,  on  the 
other  hand,  remains  insoluble.  The  artificial  silks  consist  of  cellulose 
regenerated  from  solutions,  and  perhaps  consist  of  cellulose  molecules 
which  have  not  suffered  much  condensation,  whereas  mercerised  cotton 
may  consist  of  highly  condensed  polymers  of  the  simple  cellulose  molecule, 
hence  its  dissociation  is  much  more  difficult. 

It  may,  therefore,  be  concluded  that  there  exist  various  degrees  of 
hydration  of  cotton,  and  these  may  be  determined  by  the  proportion  of 
caustic  soda  absorbed.  That  is  to  say,  the  degree  of  hydration  may  be 
measured  by  the  quantity  of  alkali  (NaOH)  absorbed  by  100  grams  of 
cotton  when  treated  with  a  2  percent  solution  of  caustic  soda.  The  follow- 
ing table  shows  this  degree  of  hydration : 


Concentration  of 

Mercerising  Liquor, 

Percent  NaOH. 

NaOH  Absorbed  per 
100  Grains  of  Cotton. 

Unmercerised 

4 

8 
12 
16 
20 
24 

1 
1 
1.4 

1.8 
2.8 
2.8 

2.8 

The  practical  determination  of  the  degree  of  hydration  of  mercerised 
cotton  may  be  made  according  to  the  following  method:  There  is  placed 
in  a  flask  200  cc.  of  a  2  percent  solution  of  caustic  soda;  50  cc.  of  this 
solution  is  titrated  with  N/2  sulfuric  acid.  In  the  remaining  solution 
there  is  placed  3  grams  of  air-dried  cotton.  After  agitating  for  thirty 
minutes,  50  cc.  of  the  solution  is  again  titrated  with  N  2  sulfmic  acid. 
The  difference  in  the  titrations  will  indicate  the  amount  of  alkali  absorbed 
by  the  cotton. 

Hydracellulose  may  also  be  formed  by  the  action  of  concentrated 
acids  under  proper  conditions.  This  accounts  for  the  mercerising  effect 
of  such  acids.  The  same  is  also  true  of  the  action  of  the  double  iodide  of 
barium  and  mercmy  and  of  solutions  of  zinc  chloride  on  cotton;  hydra- 
cellulose  is  produced  in  each  case,  and  a  mercerising  effect  is  obtained. 


MICROSCOPY  OF   MERCERISED   COTTON 


639 


When  cotton  is  treated  with  a  solution  of  sulfuric  acid  of  51°  Be., 
washed,  and  dried,  the  product  may  be  dissolved  in  a  moderately  con- 
centrated solution  of  caustic  soda  (like  viscose  or  cuprate  silks).  When 
hydrated  cotton  is  triturated  with  a  solution  of  caustic  soda  sufficiently 
concentrated  to  produce  mercerisation,  there  is  obtained  a  viscous  liquid 
which  may  be  likened  to  a  colloidal  solution.  This  solution  may  be  passed 
through  a  filter-press,  and  in  this  manner  there  is  finally  obtained  a  homo- 
geneous viscous  liquid  that  can  be  flocculated  by  the  addition  of  an  acid. 
The  precipitate  of  regenerated  cellulose  may  be  separated  by  ordinary 
filtration. 

Schwalbe  ^  has  determined  the  "  copper  numbers  "  of  cotton  treated 
with  caustic  soda  solutions  of  various  strengths,  as  follows: 


Copper  Equivalent. 

Before  Hydrolysis. 

After. 

Untreated  cotton 

1.1 
1.0 
1.3 
1.2 
1.9 

3.3 
3.2 
5.0 
6.0 
6.5 

Treated  with    8  percent  caustic  soda 

"     16       "                 "          

"     24       "                 "          

"          "    40       "                 "          

The  copper  equivalent  was  determined  in  the  usual  manner  by  treatment 
of  the  material  with  Fehling's  solution. 

24.  Microscopy  of  Mercerised  Cotton. — Microscopically  the  mercerised 
cotton  fiber  exhibits  a  considerable  difference  from  that  of  ordinary  cotton. 
Whereas  the  latter,  when  viewed  under  the  microscope,  appears  as  a 
twisted  flat  band  with  thickened  edges,  and  in  cross-section  like  a  collapsed 
tube,  mercerised  cotton  appears  as  a  rather  smooth  cyhndrical  fiber,  the 
cross-section  of  which  is  more  or  less  circular.  It  rarely  happens  that  a 
fiber  absolutely  loses  all  of  its  twist,  though  the  degree  of  mercerisation 
may  be  measured  by  the  freedom  of  the  fiber  from  irregularities  and 
twists.  Under  ordinary  conditions  when  the  cotton  is  mercerised  in  a 
state  of  tension,  it  will  also  be  found  that  many  fibers  will  remain  in  their 
original  form,  or  unmercerised,  whereas  others  will  be  mercerised  only  in 
portions  of  their  length.  The  microscopical  examination  of  mercerised 
cotton  is  important  in  determining  just  how  perfectly  the  process  has  been 
carried  out,  which  may  be  judged  by  the  relative  number  of  unmercerised 
or  partially  mercerised  fibers  which  may  be  present. 

Hanausek^  gives  the  following  description  of  the  microscopy  of  mer- 

1  Zeit.  angew.  Chem.,  1908,  p.  1321. 

2  Microscopy  of  Technical  Products,  p.  66. 


640  MERCERISED  COTTON 

cerised  cotton:  The  fibers  are  broad,  straight,  round,  and  smooth,  with  a 
hmien  which  is  either  visible  the  entire  length,  although  narrow  and 
varying  in  breadth,  or  only  occasionally  visible  so  that  the  fiber  shows  a 
row  of  streaks,  or  it  may  be  quite  invisible.  Humps  and  depressions, 
corresponding  to  folds  and  twists  of  the  original  fiber,  are  frequently 
present.  The  fibers  without  evident  lumen,  closely  resemble  silk  fibers, 
but  treatment  with  cuprammonia  brings  out  the  lumen,  and  at  the  same 
time,  certain  marked  differences  between  untreated  and  mercerised  fibers. 
The  latter  swell  uniformly  in  the  reagent,  without  marked  constrictions 
and  the  lumen  does  not  become  folded  or  coiled,  since  the  fiber  does  not 
contract  in  length.  The  uniform  swelling  is  explained  by  the  absence  of 
the  cuticle;  onl}^  in  rare  cases,  where  the  fiber  has  obviously  escaped  the 
action  of  the  mercerising  liquid,  is  the  cuticle  present.  Sometimes  the 
inner  tube  is  alternately  enlarged  and  contracted,  presenting  in  surface 
view  the  appearance  of  a  series  of  rhomboids.  In  cross-section  the  fibers 
are  nearly  circular,  with  groups  of  minute  granules  as  contents. 

25.  Lustering  by  Calender  Finish. — A  silky  luster  resembling  that 
produced  by  mercci'isation  can  be  given  to  cotton  cloth  by  means  of  what 
is  known  as  a  calender  or  Schreiner  finish.^  This  is  accomphshed  by 
passing  the  cloth  between  rollers  under  heavy  pressure,  one  of  the  rollers 
being  engraved  with  obliquely  set  lines  ruled  from  125  to  600  to  the  inch. 
The  effect  is  to  produce  a  great  number  of  parallel,  flat  surfaces  on  the 
cloth,  which  causes  it  to  acquire  a  high  luster.  By  conducting  the  opera- 
tion with  hot  rollers  quite  a  permanent  finish  can  be  produced  which 
closely  approximates  mercerised  cotton.  Cloth  so  finished,  however, 
loses  its  luster  in  a  large  degree  on  washing.  The  method  is  chiefly  known 
as  the  "  Schreiner  process,"  or  in  England  as  the  "  Hall  "  finish  or 
"  Williams  "  finish.2 

Various  methods  have  been  devised  to  make  this  method  of  lustering 
of  a  permanent  character  and  with  more  or  less  success,  such  as  treatment 
of  the  calender  goods  with  steam  under  pressure^  or  by  finishing  the 
cloth  with  a  fine  layer  of  size  which  is  insoluble  in  water,'* 

iSee  H.  Fischer,  Zeit.  Farb.  Ind.,  1907,  p.  271.  Also  see  Deisler,  Ger.  Pat.  85,368 
(Schreiner  patent);  Appleby,  Brit.  Pat.  170  of  1860;  and  Kirkham,  Brit.  Pat.  4593 
of  1885  and  10,825  of  1899;  Hubner  and  Pope,  Ger.  Pat.  167,930;  Keller-Dorian, 
Ger.  Pat.  185,835;    Eck  u.  Sohne,  Ger.  Pat.  197,589;   Hall,  Ger.  Pat.  177,241. 

2  See  also  Gardner,  Merzerisation  rmd  Appretur,  p.  150. 

3  See  Sharp,  Brit.  Pat.  16,746  of  1897. 

^  See  Bradford  Dyers'  Association,  Ger.  Pot.  212,696  and  212,695  on  the  use  of  cel- 
lulose nitrate  solutions;  this,  however,  is  expensive  and  leaves  an  objectionable  odor. 
Miiller,  Ger.  Pat.  222,777,  uses  celluloid  dissolved  in  dichlorhydrin ;  this  is  also  too 
expensive.  During,  Ger.  Pat.  206,901  and  217,679  uses  albumen  and  casein  solutions 
which  are  coagulated  by  steaming.  Eck  u.  Sohne,  Ger.  Pat.  232,568,  use  an  acid 
gelatine  solution  and  coagulate  by  neutralising;  this  method,  however,  is  expensive. 
Bernhard,  Ger.  Pat.  233,514,  uses  a  dilute  solution  of  rubber,  wax  or  paraffin  in  benzene, 
which  is  also  an  expensive  method. 


LUSTERING  BY  CALENDER  FINISH 


641 


The  present  day  so-called  permanent  luster  finish  (also  known  as  the 
Radium  or  Adler  finish)  is  obtained  by  first  finishing  the  cloth  on  the 
engraved  calender  for  silk  luster  and  then  fixing  on  another  calender  at 
high  temperature  ^  and  under  great  pressm'e  (up  to  300,000  lbs.).  The 
higher  the  temperature  the  higher  the  luster  (generally  200-300°  C). 

In  the  Rumpf  process  ^  the  goods  (cotton  piece-goods,  cotton  plush, 
velvet,  and  the  like)  are  first  submitted  to  a  preliminary  treatment. 


Fig.  247. — Calender  for  Schreiner  Finish, 


This  consists  in  the  goods  being  strongly  moistened  and  a  high  shiny 
gloss  then  imparted  to  them  by  means  of  hot  calendering  or  pressing,  or 
by  lustering.  The  shiny  gloss  so  produced  is  then  for  the  most  part  fixed 
by  submitting  the  goods,  preferably  in  a  stretched  condition,  to  heat  of  a 
high  temperature  by  passing  them  for  a  long  time  through  a  very  hot 
calender,  or  by  passing  them  through  gas  flames,  or  more  frequently  by 
passing  them  over  a  strongly  heated  drum,  or  rolhng  them  up  thereon. 
If,  in  producing  the  gloss  by  the  calender  process,  temperatures  of  400°  C. 

1  See  Aderholt,  Ger.  Pat.  235,701.  ^  Ger.  Pat.  220,349. 


642 


MERCERISED   COTTON 


and  over  are  used,  it  is  possible  with  even  one  or  two  passages  to  obtain 
a  sufficient  fixation  with  one  treatment.  By  the  action  of  the  heat  a  part 
of  the  gloss  produced  is  lost  owing  to  the  displacement  of  the  fibers,  and 
cannot  therefore  be  fixed  by  the  heat.  In  order  to  remedy  this  defect 
the  goods  are  previously  treated  by  anj^  shiny  adhesive  material,  prefer- 
ably containing  starch.  The  goods  are  then  drawn  off — that  is,  treated 
with  water,  soap  solution,  moist  steam,  or  other  solution,  and  if  starch 
has  been  employed,  with  malt  or  malt  extract,  whereby,  as  is  known,  the 
fatty  gloss  disappears  and  a  clean  and  equable  silky  gloss  remains,  which 


Fig.  248. — Hydraulic  Schreiner  Calender. 


is  then  water  and  soap  proof.  The  amount  of  gloss  obtained  depends 
primarily  upon  the  amount  of  gloss  imparted  in  the  preliminary  treatment 
to  the  goods.  The  degree  of  fixing,  however,  depends  principally  upon 
the  temperature  to  which  the  action — that  is,  the  fixation — of  the  gloss 
is  proportionate.  The  heating  is  therefore  carried  as  far  as  possible  with- 
out damaging  the  goods. 

In  the  Palmer  process  ^  the  materials  are  passed  while  quite  wet 
through  strongly  heated  rollers  with  such  a  speed  (30  to  40  meters  per 
minute)  that  in  spite  of  the  great  pressure  and  the  high  temperature  they 

1  Brit.  Pat.  20,645  of  1909. 


LUSTERING  BY  CALENDER  FINISH  643 

emerge  still  wet.  The  water  acts  in  this  case  as  a  protective  means,  in 
that  it  limits  the  effect  of  the  heat  upon  the  sm-faces,  and  protects  the 
center  of  the  material  against  destruction  by  the  penetration  of  the  heat, 
so  that  a  superficial  luster  is  formed  only  at  the  areas  of  contact  of  the 
material  with  the  rollers.  At  the  same  time  the  steam  evolved  from  the 
material  upon  pressing  removes  in  one  operation  the  base  and  unperma- 


FiG.  249. — Improved  T^je  Hydraulic  Schreiner  Calender.     (Text.  Fin.  Mchy.  Co.) 

nent  part  of  the  luster,  without  any  special  subsequent  damping  being 
first  required.  In  order  to  provide  the  material  with  permanent  luster 
on  both  sides,  it  is  passed  through  two  calendering  machines  in  series  one 
after  the  other;  the  steel  roller  of  one  calender  hes  beneath,  and  that  of  the 
other  on  top.  In  order  to  raise  the  flattened  shape,  the  yarns  can,  if 
desired,  be  subsequently  soaked  in  hot  water.  Instead  of  employing 
simple  pressure,  the  latter  may  be  combined  with  friction — e.g.,  by  dif- 


644 


MERCERISED   COTTON 


ferent  speeds  of  the  two  rollers,  placing  them  obliquely,  and  so  on.  In  a 
similar  way  to  yarns,  other  products  consisting  of  vegetable  threads  can 
also  be  treated,  such  as  woven  goods,  fabrics,  etc.,  for  which  as  a  rule 
treatment  on  one  side  is  sufficient.  An}'  kind  of  roller  (polished,  engraved, 
etc.)  may  be  employed  as  the  pressure  roller.  This  process  can  be  em- 
ployed upon  both  mercerised  and  non-mercerised  fabrics.^ 

Hamberg  and  Poznanski  have  described  a  combination  of  mercerisa- 
tion  and  goffering  to  obtain  patterns  in  relief  that  will  withstand  washing. 
The  fabric  is  passed  between  two  calender  rollers,  one  of  which  bears  the 
pattern  in  relief,  the  other  in  intaglio.  If  the  two  rollers  are  in  register, 
the  pattern  will  be  printed  without  tlistortion,  and,  at  the  same  time,  both 
warp  and  weft  threads  will  be  stretched  in  the  pattern.  If  the  fabric  is 
then  treated  with  caustic-soda  lye  by  passing  it  over  a  roller  turning  in 


li     '. 

1 

i 

^M 

1 

m  Jl 

■ 

^v 

f 

^^^^H 

^^HH 

B 

Fig.  250. — Gauffer  Finish  on  Cotton  Cloth. 


the  lye,  but  with  the  unprinted  side  in  contact  with  that  roller,  the  con- 
traction of  the  wrong  side  will  make  the  pattern  permanent;  the  lye 
answers  best  in  this  particular  manner  of  use  if  thickened  with  dextrin. 
The  goods  are  then  ironed  and  prepared  in  the  usual  manner;  these  pat- 
terns are  claimed  to  be  fast  to  washing  with  boiling  water  (Fig.  250). 
If  the  raised  parts  of  the  pattern  are  treated  with  a  reserve  to  protect  them 
from  mercerising  lye,  a  similar  effect  is  obtained.  Another  method  is  to 
paint  the  raised  parts  of  one  roller  with  a  thickened  lye,  so  that  in  contrast 

1  A  rather  pecuHar  process  of  lustering  is  that  of  impregnating  the  goods,  either 
in  the  dry  or  wet  concUtion,  with  a  crystallisable  salt  solution,  such  as  sodium  chloride 
or  chloride  of  ammonium,  after  which  the  goods  are  passed  repeatedly  through  a 
calender  heated  to  about  100°  to  200°  C.  The  surface  gloss  from  the  steam  is  then 
obliterated  from  the  goods  in  an  ordinary  manner,  and  the  appearance  of  the  goods 
may  be  rendered  more  refined  hy  working  it  through  fluted  rollers.  After  this  there 
remains  a  silk-like  gloss  due  to  minute  crushed  crystals  intimately  distributed  over 
all  the  fibers  throughout  the  fabric.  It  is  claimed  that  the  goods  thus  treated  can  be 
placed  in  water  for  days  without  materially  losing  the  gloss. 


OTHER   jMETHODS  OF  LUSTERING  COTTON  645 

to  the  last  method,  it  is  the  pattern  that  contracts  instead  of  the  ground. 
Dyeing  effects  can  be  obtained  ^vith  fabrics  so  treated,  according  to  the 
parts  that  have  been  mercerised,  and  according  to  the  degree  of  ornamen- 
tation. For  example,  hght  patterns  on  a  dark  ground  may  be  readily 
obtained,  or  vice  versa.  White  raised  effects  can  be  made  on  a  colored 
ground  by  adding  dyes  to  the  mercerising  lye,  and  interesting  and  valu- 
able effects  can  also  be  obtained  by  raising  the  patterns  in  rehef  on  the 
gig  so  that  the  raised  parts  show  up  strongly  on  the  unraised  and  flat- 
looking  ground  portions  of  the  design. 

Another  method  of  goffer  lustering  is  described  bj-  Oliver  ^  as  follows: 
To  a  mixture  of  455  grams  sandarac  gum  and  910  grams  castor  oil,  113 
grams  of  fine  celluloid  waste  and  amyl  acetate  reduced  to  a  paste  are  added 
and  finally  2.5  liters  of  methyl  alcohol  to  give  a  sjTupy  consistency.  The 
fabric  is  sprinkled  with  this  composition  and  passed  into  the  goffering 
rollers  and  then  dried. 

26.  Other  Methods  of  Lustering  Cotton. — Another  important  finishing 
method  for  cotton  whereb}-  the  character  of  the  surface  is  changed  by 
mechanical  means  to  give  it  the  quality  of  chamois  or  moleskin  is  known 
as  the  "  Duvetyn  "  finish.  This  finish  is  produced  on  cotton  fabrics  by 
"  emerising."  It  has  enjoj^ed  a  run  of  popularitj',  and  is  still  in  favor. 
At  the  time  of  its  introduction  it  was  worked  as  a  secret  process,  different 
finishers  employing  methods  differing  perhaps  in  some  detail  or  another. 
Experience  with  the  work  has  brought  improvements,  and  one  of  these 
forms  the  subject  of  an  invention  by  the  Societe  Durbar-Delespaul,  of 
Roubaix.-  It  is  an  application  of  the  weU-known  process  of  raising  or 
"  emerising,"  and  it  is  stated  by  the  inventors  that  the  patent  involves 
no  improvement  in  the  technique  of  that  process.  The  ''  emerising  " 
process  is  used  generally  on  cotton  goods  woven  in  such  a  way  that  the 
weft  floats  on  the  face  of  the  cloth  and  the  warp  on  the  back,  much  the 
same  as  a  moleskin.  This  process  of  finishing  does  not  require  any 
special  treatment  in  the  weaving,  and  is  equally  as  well  adapted  for  worsted 
or  carded  woolen  fabrics  as  for  cotton.  The  fabrics  are  emerised  either 
in  the  gray  or  after  dyeing  or  printing.  The  process  changes  the  surface 
of  the  cloth — gives  it  the  appearance  of  velveteen,  chamois,  or  the  skin 
of  the  mole.  The  operation  is  very  simple,  and  consists  of  subjecting 
the  cloth  in  two  or  three  passages  to  the  action  of  several  rollers  which 
revolve  rapidly  in  a  direction  opposite  to  that  in  which  the  cloth  is  moving. 
These  rollers  are  covered  with  emerj'  cloth. 

Pulverised  flint,  stone,  glass  or  sand  may  be  substituted  for  the  emery. 

The  action  of  the  roller  on  the  weft  of  the  cloth  produces  a  very  short, 

thick  nap,  with  the  fibers  standing  straight  from  the  surface  of  the  cloth. 

The  extent  of  this  action  depends,  of  course,  on  the  nature  of  the  fabric 

1  Fr.  Pat.  508,241.  2  fj..  Pat.  449,266. 


646  MERCERISED   COTTON 

to  be  finished,  and  is  regulated  by  the  tension  of  the  cloth,  the  speed 
and  number  of  the  rollers,  and  on  the  fineness  of  the  emery  with  which 
the  rollers  are  covered.  It  is  evident  that  carded  woolen  goods  can  be 
finished  by  this  process  more  easily  than  worsteds,  owing  to  the  difference 
in  the  twist  of  the  yarn.  Emerising  differs  radically  from  napping  or  raising 
on  the  ordinary  raising  machine:  the  latter  tears  the  fibers  from  the  thread 
in  order  to  form  the  nap.  Emerising  consists  not  in  tearing  the  fibers 
out,  but  in  wearing  or  polishing  the  surface.  Both  raising  and  emerising, 
however,  serve  the  purpose  of  reducing  the  strength  and  solidity  of  the 
fabric.  In  order  that  the  nap  may  be  uniform  it  is  necessary  that  the 
fabric  should  possess  a  certain  degree  of  stiffness.  For  this  reason  the 
cloth  is  heavily  sized,  and  this  prevents  the  action  of  the  emerj'  penetrating 
deeply  into  the  fibers.  The  ordinary  glue  used  in  finishing  answers  the 
purpose,  and  after  it  has  been  applied  the  material  is  dried  thoroughly 
before  emerising.  By  covering  the  rollers  with  bands  of  emery  the 
Duvetyn  finish  can  be  produced  in  the  form  of  stripes. 

27.  Crepe  Effects  by  Mercerising. — Crepe  effects  may  be  produced 
on  all-cotton  goods  by  employing  mercerised  cotton  yarns  for  the  warp, 
suitably  protecting  these  with  gum,  and  then  using  plain  cotton  yarns 
for  the  filling,  and  finally  mercerising  the  woven  fabric.  The  filling 
yarns  will  contract  and  thus  give  a  crinkled  or  creped  fabric. 

Crepe  effects  on  cotton-wool  fabrics  may  also  be  produced  by  the 
process  of  mercerisation.  If  the  cotton  is  used  in  the  fabrics  in  either 
stripes  of  pattern  effect  it  may  be  shrunk  suitably  by  treating  the  fabric 
with  strong  solutions  of  caustic' soda  without  tension.  If  a  caustic  soda 
solution  of  50°  Tw.  is  used  at  a  temperature  below  10°  C.  and  for  one  to 
three  minutes,  the  cotton  will  be  properly  shrunk  without  affecting  the 
strength  or  quality  of  the  wool,  the  latter  fiber  only  becoming  somewhat 
lustered  and  hardened. 

The  usual  method  of  creping  cotton  fabrics,  however,  is  to  employ  the 
mercerising  reaction  in  connection  with  printing.  By  printing  on  a 
strongly  caustic  paste  in  stripes  or  any  other  pattern  effect,  that  portion 
of  the  cotton  fabric  subjected  to  the  action  of  the  caustic  soda  will  con- 
tract considerably,  leaving  the  rest  of  the  fabric  in  its  natural  condition. 
In  this  manner  seersucker  and  crinkled  effects  of  various  kinds  may  be 
obtained.  After  the  caustic  soda  paste  has  been  printed  on  the  cloth, 
it  is  run  for  a  short  space  so  as  to  give  the  necessary  time  for  the  com- 
pletion of  the  mercerising,  but  it  is  not  dried  as  in  ordinary^  processes  of 
printing,  as  the  drying  in  of  the  strong  caustic  soda  solution  would  be 
injurious  to  the  cotton.  After  the  action  of  the  caustic  soda  is  finished 
the  printing  paste  is  washed  off  and  the  goods  are  soured  by  treatment 
with  a  dilute  solution  of  acetic  or  sulfuric  acid.  As  the  mercerised  fibers 
in  this  case  are  not  maintained  under  tension,  there  will  not  be  any  luster 


SWISS   FINISH  OR  MERCERISING  WITH  ACID  647 

developed,  but  as  the  object  of  the  process  is  to  cause  the  cloth  to  shrink 
in  pattern  effect,  the  question  of  luster  does  not  enter  into  the  case. 

Other  methods  of  creping  may  also  be  employed;  such,  for  example, 
as  that  of  first  printing  on  a  paste  containing  a  substance  capable  of  acting 
as  a  resist  against  the  action  of  the  caustic  soda.  Neutral  protective 
materials,  such  as  China  clay,  or  acid-bearing  substances,  such  as  alum, 
may  be  used.  Under  such  conditions,  by  treating  the  printed  cloth 
with  a  mercerising  solution  of  caustic  soda,  only  those  parts  which  are  not 
protected  by  the  printing  will  be  mercerised  and  will  shrink,  leaving  the 
other  parts  in  their  natural  condition,  after  the  paste  has  been  washed 
off. 

By  printing  with  a  resist  paste  and  then  mercerising  under  tension, 
it  is  possible  to  obtain  a  fabric  that  is  mercerised  and  lustered  in  pattern 
effect  on  an  unmercerised  and  lusterless  background,  giving  rise  to  a 
damask  effect. 

A  variation  in  the  usual  mercerising  process  is  suggested  in  a  patent 
of  Heberlein.^  The  3-am  or  cloth  is  impregnated  with  a  solution  of  300 
grams  of  starch  in  10  hters  of  caustic  soda  lye  at  33°  Tw..  the  materials 
being  immersed  in  this  solution  for  about  ten  minutes  in  the  stretched 
condition,  and  then  washed  \dth  water,  dilute  acid  and  again  with  water. 
The  cotton  treated  in  this  manner  is  said  to  acquire  a  silky  luster  and  a 
stiffness  which  is  not  lost  by  subsequent  washing  or  dyeing.  The  process 
was  suggested  as  useful  for  the  manufacture  of  polished  yams.  This 
process  also  contains  the  germ  of  the  methods  subsequently  discovered 
by  this  same  inventor  of  gi^"ing  cotton  fabrics  a  permanently  stiff  finish 
by  mercerising  and  then  treating  with  suffuric  acid. 

Knecht  recently  described  a  new  process  of  mercerising,  which  depends 
upon  the  action  of  hydrochloric  acid  of  particular  strength  (37°  to  3S°  Tw.\ 
This,  he  said,  not  only  brought  about  a  shrinkage  of  the  cotton,  but  also 
an  enormously  increased  affinity  for  the  majority  of  coloring  matters. 
The  duration  of  the  action  was  thirty  seconds,  and  it  did  not,  he  said, 
bring  about  any  ''  tendering  "  or  deterioration  of  the  fiber.  Knecht 
thought  that  the  reason  why  the  action  of  such  a  common  reagent  as 
hydrochloric  acid  had  never  been  detected  before  was  because  the  par- 
ticular strength  of  hydrochloric  acid  to  which  he  referred  was  not  com- 
mercial, and  its  beha^^ior  toward  various  substances  had  not  been  par- 
ticularly studied.  The  reagent,  he  obser\"es  is  cheap,  and  the  washing- 
out  of  the  acid  may  be  completely  effected  in  a  minimum  of  time. 

28.  Swiss  Finish  or  Mercerising  with  Acid. — This  finish,  which  makes 
the  cotton  translucent,  lustrous,  and  stiff,  has  been  chiefly  developed  by 
the  Swiss  chemist  Heberlein.  The  starch-hke  stiffness  of  the  fabric  is 
permanent  against  the  action  of  repeated  washing  or  laimdering.     The 

1  Brit.  Pat.  27,529  of  1S9S. 


648  MERCERISED  COTTON 

treatment  consists  essentially  of  mercerising  the  cotton  fabric  (usually 
voile,  organdie,  or  other  light-weight  material)  with  strong  caustic  soda 
liquor  and  then  subjecting  it  to  the  action  of  a  strong  sulfuric  acid  solu- 
tion, and  finally  removing  the  acid. 

Mercer,  in  the  year  1844,  and  others  later,  have  observed  that  if  con- 
centrated sulfuric  acid  is  allowed  to  act  on  cotton  the  fabric  acquires  a 
parchment-like  character.  This  effect  is  simply  the  extension  of  the 
general  reaction  of  strong  sulfuric  acid  on  cellulose,  which  had  long  before 
been  observed  in  the  case  of  paper  and  which  has  been  commercially 
employed  in  the  manufacture  of  parchment  paper.  According  to  Mercer 
this  effect  is  obtained  by  the  use  of  sulfuric  acid  of  49.5°  to  55.5°  Be.,  and  he 
observed  that  the  cotton  apparently  underwent  a  chemical  change  that 
made  it  more  susceptible  to  the  action  of  certain  dyes.  It  was  apparently 
Mercer  who  was  the  first  to  observe  the  effect  of  this  acid  treatment  on 
paper.  By  treating  paper  with  sulfuric  acid  of  various  strengths  from 
115°  to  125°  Tw.  and  at  a  temperature  of  50°  F.  he  found  the  paper  to  be 
translucent  and  considerably  strengthened.  The  paper  used  could  be 
either  sized  or  unsized.  By  impregnating  it  with  gelatine  and  drying  pre- 
vious to  dipping  it  in  the  acid,  he  obtained,  after  washing  and  drying,  a 
"  very  fine  white  paper,  which  folds  quite  easily,"  to  quote  his  own  remarks. 
This  "  mercerised  "  paper  was  probably  regarded  by  Mercer  rather  as  an 
article  of  curiosity  than  as  one  of  practical  value ;  but  a  few  years  afterward 
it  became  manufactured  extensively  by  others  as  the  useful  material 
now  known  as  "  parchment  "  paper.  It  is  customary  to  employ  unsized 
paper  and  to  immerse  it  in  sulfuric  acid  diluted  with  one-third  to  one- 
quarter  its  volume  of  water  and  cooled.  The  cellulose  fiber  is  rapidly 
attacked,  the  paper  becoming  transparent  owing  to  the  swelling  and 
gelatinisation  of  the  fibers,  and  after  this  the  reaction  quickly  becomes  one 
of  solution.  But  if  the  time  of  treatment  is  properly  regulated  and  the 
treated  paper  rapidly  washed  in  water,  the  acid  compound  is  decomposed, 
and  the  resulting  gelatinous  hydrate  of  cellulose  is  fixed  as  a  constituent 
of  the  paper.  When  the  product  is  exhaustively  washed  and  dried  it 
gives  a  tough  translucent  sheet.  The  changes  which  the  cellulose  under- 
goes in  this  treatment  have  been  studied  by  Guignet.^ 

The  use  of  sulfuric  acid  was  included  in  Mercer's  Patent  of  1850  for 
"  Improvements  in  the  Preparation  of  Cotton."  The  action  of  this  acid, 
like  that  of  caustic  alkali,  varies  considerably  with  the  strength,  tempera- 
ture, and  time  allowed  for  action.  Weak  acid  as  well  as  strong  produces 
disintegration  of  the  fiber,  but  exposure  for  a  few  minutes  to  acid  of  104° 
to  125°  Tw.,  at  ordinary  temperatures,  produces  a  modification  of  the 
fiber  without  impairing  its  tenacity.     If  the  object  is  to  enhance  the 

1  Soluble  and  Insoluble  Colloidal  Cellulose  and  Composition  of  Parchment  Paper, 
Comptes  rendus,  vol.  108,  p.  1258. 


SWISS  FINISH  OR   MERCERISING   WITH  ACID  649 

color  receptive  power  of  cotton  cloth  without  injury  to  the  fiber,  Mercer 
considered  the  best  strength  to  be  about  104°  Tw.  at  50°  to  60°  F.  The 
cloth,  which  should  be  in  a  condition  to  absorb  hquids  quickly,  was  passed 
over  and  under  rollers  so  as  to  be  in  the  acid  for  one  minute,  then  through 
squeezers,  and  finally  washed  by  a  series  of  rollers  in  water.  Sulfuric 
acid  of  104°  Tw.  produces  very  httle  immediate  effect.  Mercer  regarded 
the  effective  hydrate  to  be  the  "  terhydrate  "  (H2SO4  •2H2O)  of  125°  Tw., 
but  acid  of  that  strength  was  found  by  him  to  be  too  energetic  for  practical 
use  imder  the  conditions  with  which  he  operated.  He  made  the  following 
observations  regarding  the  action  of  sulfuric  acid  of  different  strengths 
on  cotton  and  paper:  "  Three  stages,  or  perhaps  more,  may  be  recognised 
in  the  action  of  sulfuric  acid.  The  first  action  seems  to  be  the  expansion 
and  ruptm'e  of  the  fiber;  to  effect  which  the  strength  of  the  acid  should 
be  about  110°  Tw.  at  a  temperature  of  about  50°  F.  "WTien  washed  and 
dried  the  cloth  is  not  stiff  as  is  the  case  with  stronger  acid,  but  very  soft 
and  feels  similar  to  glove  leather.  It  is  not  much  contracted,  and  can  be 
easily  stretched  to  its  original  size.  It  is  very  white  and  its  power  of 
receiving  color  is  greatly  augmented.  It  is  to  cloth  of  this  character 
that  my  patent  relates.  The  next  stage  is  exhibited  with  acid  of  about 
114°  to  115°  Tw.,  at  the  same  temperature.  This  strength  causes  con- 
siderable contraction  of  the  cloth.  When  washed  and  dried  under  pres- 
sure between  folds  of  bleached  cloth,  it  is  stiff  and  white,  having  the 
appearance  of  being  impregnated  with  a  dense  white  precipitate.  It 
cannot  be  stretched  to  its  original  dimensions.  If  the  cloth  is  impregnated 
with  milk  and  dried  before  being  immersed  in  the  acid,  it  looks  stiU  whiter 
and  more  beautiful.  Sulfuric  acid  stronger  than  the  above — namely,  from 
116°  to  125°  Tw.,  at  the  temperature  of  50°  F.  produces  another  marked 
effect.  With  this  the  cloth  becomes  semi-transparent.  It  is  stiff  and 
much  contracted.  If  a  design  is  first  penciled  or  printed  with  a  protecting 
paste  of  albumen,  solution  of  casein,  or  thick  gum  water,  and  dried  before 
being  put  into  the  acid,  the  design  is  preserved  and  a  very  pleasing  effect 
may  be  produced.  When  paper  or  cotton  is  digested  for  a  Uttle  time  in 
acid  not  stronger  than  115°  Tw.  at  common  temperatures,  it  dissolves, 
forming  a  thick  pasty  liquid,  which,  when  poured  into  water,  gives  a 
white  precipitate  something  like  boiled  rice,  ver}^  soluble  in  caustic  soda." 

Blondell  ^  has  also  observed  that  sulfuric  acid  of  90°  to  106°  Tw. 
imparts  to  cellulose  the  capacity  of  being  brightly  colored  with  Methyl 
Blue,  whereas  a  parchmentising  effect  only  results  when  the  suKuric 
acid  is  of  a  concentration  of  from  116°  to  125°  Tw. 

The  work  of  Georges  Heberlein,  of  Switzerland,  has  been  detailed  in 
quite  an  array  of  patents,  among  which  the  following  are  the  more  impor- 
tant: Ger.  Pats.  280,134,  290,444,  and  294,571;  Fr.  Pats.  468,642,  468,821, 
'  Bull.  Soc.  Ind.  Rouen,  1882,  pp.  438  and  471. 


650  MERCERISED   COTTON 

and  481,561;  Brit.  Pats.  12,559  of  1914,  13,129  of  1914,  and  100,483  of 
1915;    U.  S.  Pats.  1,392,264  and  1,392,265. 

Heberlein  states  that  he  has  discovered  that  sulfuric  acid  of  a  con- 
centration of  51°  Be.  (109°  Tw.)  and  above  produces  on  the  cellulose  an 
entirely  different  effect  than  that  produced  thereon  by  an  acid  whose 
concentration  is  below  51°  Be.  Although  a  more  highly  concentrated 
sulfuric  acid  imparts  to  cotton  fabric  after  a  few  seconds'  action  a  typical 
parchment-like  appearance,  such  an  acid  of,  for  example,  50°  Be.  (106°  Tw). 
even  after  acting  for  fifteen  minutes,  will  not  cause  a  like  alteration  of  the 
cellulose,  and  in  contradistinction  to  the  effect  of  a  slightly  stronger  acid, 
the  fabric  will  not  be  weakened  b}'  even  longer  action.  Heberlein  also 
states  that  the  action  of  sulfuric  acid  of  a  concentration  under  51°  Be. 
(109°  Tw.)  will  be  much  more  intensive  and  will  impart  to  cotton  entirely 
new  qualities  if  the  cotton  has  been  previously  mercerised,  because  it  is 
rendered  thereb}'  more  susceptible  to  the  action  b}'  the  acid.  If  cotton 
fabric  which  has  been  mercerised  and  also  preferably  bleached,  be  sub- 
jected to  the  action  of  sulfuric  acid  of  from  49°  to  50^°  Be.  (103°  to  108° 
Tw.),  the  mercerising  luster  disappears  and  instead  of  the  transparency 
obtained  with  the  higher  concentrations,  the  fabric  assumes  a  fine  crepe- 
like natur(>,  whereby  it  appears  thicker,  fuller,  and  more  wool-like,  softer, 
and  generally  improved  in  its  entire  quality,  and  takes  on  the  character 
of  a  fine,  thin  woolen  material.  This  is  the  novel  finishing  effect  introduced 
b}'  Heberlein. 

The  process  ma}'  be  apphed  to  the  treatment  of  plain,  patterned,  or 
embroidered  fabrics.  Pattern  effects  may  also  be  produced  on  plain 
fabrics  b}'  printing  sulfuric  acid  of  50°  Be.  (106°  Tw.)  on  a  mercerised 
cloth  and  washing  out  the  acid  after  the  action  has  been  completed. 
These  may  also  be  printed  on  a  suitable  resist,  such  as  a  gum  thickening, 
and  then  the  entire  fabric  ma}'  be  dipped  into  sulfuric  acid  of  the  con- 
centration mentioned.  At  the  points  where  the  acid  has  acted  the  cloth  will 
exhibit  the  effect  mentioned  above,  so  in  this  manner  designs  or  patterns 
of  a  combination  of  lustrous  mercerised  cotton  cloth  with  a  dull  wool-like 
fabric  may  be  obtained. 

The  time  that  the  sulfuric  acid  should  be  allowed  to  act  will 
depend  on  the  nature  of  the  fabric  being  treated;  in  some  cases  only 
a  few  seconds  are  required,  while  in  others  several  minutes  will  be 
necessary. 

The  fabric  may  also  be  first  treated  with  the  acid,  washed,  and  then 
without  stretching,  mercerised  with  caustic  soda.  Heberlein  also  states 
that  the  sulfuric  acid  may  be  replaced  by  phosphoric  acid  of  55°  to  57°  Be. 
(123°  to  130°  Tw.),  or  with  hydrochloric  acid  of  sp.  gr.  1.19°  at  low  tem- 
perature, or  with  nitric  acid  of  43°  to  46°  Be.  (85°  to  94°  Tw.),  or  with 
zinc  chloride  solution  of  66°  Be.  (168°  Tw.)  or  with  copper  oxide  ammonia 


SWISS   FINISH   OR    MERCERISING   WITH   ACID  651 

solution  -^-ith  a  short  reaction  period.     But  the  best  effects  are  claimed 
to  be  obtained  with  the  use  of  sulfuric  acid. 

In  U.  S.  Patent  1,392,265,  Heberlein  describes  the  use  of  sulfuric  acid 
in  concentrations  over  50.5°  Be.  (108°  Tw.)  for  the  purpose  of  producing  a 
fabric  having  a  parchruentised  appearance,  especially  one  having  greater 
transparency.  He  uses  mercerised  cotton  for  this  purpose  as  it  has  greater 
reactivity  ys'ith  the  acid.  Heberlein  states  his  process  and  the  effects  as 
foUows : 

"It  is  a  characteristic  of  cotton  fabric  treated  according  to  my  process,  that  it  is 
really  quite  transparent,  giving  the  effect  or  appearance  of  a  high  grade  transparent 
'organdie,'  and  that  the  fibers  are  bright  and  clean,  and  give  to  the  fabric  a  bright 
or  sheen  effect,  and  a  smooth,  finished  appearance  in  contrast  to  the  duU,  rough, 
unfinished  truly  parchmentised  effect  which  is  characteristic  of  cotton  fabrics  pro- 
duced by  simply  treating  the  ordiuarj'  cotton  fabric  with  sulfuric  acid,  as  had  been 
known  prior  to  my  above  set  forth  process.  It  is  also  a  characteristic  of  fabrics  treated 
according  to  my  process,  that  their  chemical  structural  change  is  permanent;  namely, 
wiU  withstand  repeated  laimdering  so  that  the  goods  may  be  laundered  without  ehm- 
inating  or  materially  altering  the  said  characteristics,  and  this  greatlj'  enhances  their 
value. 

"■^Miere  the  entire  fabric  is  treated  according  to  my  above  process,  the  heretofore 
described  transparent  effect  is,  of  course,  produced  all  over  the  fabric  so  as  to  pro\'ide 
a  transparent  fabric  of  pleasing  effect  which  has  a  bright  clean  appearance  with  some- 
what of  a  sheen  resembling  high  grade  transparent  organdies;  and  where  only  portions 
of  the  fabric  are  treated  according  to  my  invention  and  the  other  parts  remain  as 
unaltered  mercerised  fabric,  so  as  to  produce  pattern  effects,  of  course  the  mercerised 
parts  remaining  untreated  retain  the  physical  characteristics  of  mercerised  cotton,  in 
that  thej'  are  soft,  glossj^  and  opaque,  and  show  up  in  striking  manner  in  contrast  to 
the  transparent  portions. 

"I  have  also  foimd  that  a  still  more  enhanced  transparency  of  the  cotton  fabric 
can  be  obtained  by  an  improved  process,  according  to  which  sulfuric  acid  of  over 
504°  Be.  and  concentrated  caustic  alkaU  are  caused  to  act  upon  cotton  fabric  several 
times  alternateh',  the  sulfuric  acid  being  always  allowed  to  act  only  for  a  few  seconds. 

"In  order  to  obtain  this  greater  or  enhanced  transparency  as  compared  with  that 
obtained  by  my  first  mentioned  process,  it  is  necessarj'  that  one  of  the  two  agents 
be  applied  at  least  twice  with  an  intermediate  treatment  of  the  other,  as  for  example, 
caustic  soda — sulfuric  acid — caustic  soda,  or  nee  versa.  In  between  the  reactions  the 
goods  must  be  well  washed,  and  subsequently  dried. 

"If  cotton  fabric  treated  with  concentrated  caustic  soda  is  subjected  for  the  second 
time  to  the  same  treatment  no  further  change  takes  place  in  the  same.  That  is,  the 
second  caustic  treatment  remains  without  effect  on  the  fabric.  Cotton  fabric  behaves 
in  similar  manner  toward  repeated  treatments  with  concentrated  sulfuric  acid.  If, 
however,  the  cotton  fabric  that  has  been  mercerised  has  been  subsequently  exposed  to 
the  action  of  concentrated  sulfuric  acid,  and  then  to  caustic  soda,  the  caustic  soda 
reacts  anew  upon  the  fabric  and  effects  a  further  change.  The  same  is  true  if  the 
first  treatment  is  with  the  concentrated  sulfuric  acid,  and  then  the  next  treatment  with 
caustic  soda  and  another  treatment  with  sulfuric  acid.  In  each  such  alternate  treat- 
ment the  acid  or  alkaH,  as  the  case  may  be,  will  again  work  or  be  effective  upon  the 
fibers  of  the  fabric  to  alter  them  further.  The  alternate  treatment  with  acid  and 
alkali  can  be  several  times  repeated . 


652  MERCERISED  COTTON 

"It  is  evident  that  varied  degrees  of  transparency  are  obtained  according  to  the 
number  of  manipulations  or  alternate  treatments.  Modifications  in  the  quality  of 
the  fabric  can  also  be  obtained  by  either  stretching  the  same  more  or  less  during  the 
treatment,  or  by  having  the  same  more  or  less  shrunk  in  the  longitudmal  and  cross 
directions. 

"Finally  transparent  pattern  elTects  may  be  obtained  by  printmg  the  alkali  or  the 
acid  at  one  or  more  of  the  operations  only  upon  particular  portions  of  the  fabric,  or 
by  printing  on  particular  portions  of  the  fabric  a  resist  (for  instance,  gum  thickening) 
either  at  the  commencement  of  the  treatment  or  between  the  first  and  the  second  or 
between  two  successive  operations,  the  said  resist  preventing  a  further  reaction  of  the 
alkali  or  the  acid.  For  example,  it  will  be  obvious  from  the  above  that  if  the  aforesaid 
l^attern  effect  of  glossy  mercerised  portions  and  of  transparent  portions  is  to  be  pro- 
duced, the  fabric  can  be  treated  with  alkali  all  over,  then  a  resist  of  the  design  put  on 
and  then  the  background  is  treated  with  acid  and  then  with  alkali." 

The  product  described  has  become  a  very  important  article  of  trade 
and  is  generally  known  as  "  permanent  finish  "  Swiss  voile,  or  the  like. 
It  is  also  being  made  in  the  United  States,  presumably  under  license  from 
the  Swiss  inventors.  The  chief  problem,  however,  to  be  solved  in  the 
manufacture  of  this  material  is  not  that  of  the  requisite  chemical  treat- 
ment, which  had  already  been  more  or  less  definitely  described  by  Mercer 
a  good  many  years  ago,  but  the  manner  of  handling  the  goods  in  the 
treatment  so  as  to  obtain  a  commercial  product  without  injury  to  the 
fabric.  This  problem  is  an  intricate  one  of  mechanical  engineering,  and 
it  has  been  moi'e  by  reason  of  the  proper  solution  of  these  engineering 
problems  that  the  process  has  become  commercially  available  than 
through  the  "  discovery  "  of  the  chemical  treatment. 

In  U.  S.  Patent  1,395,472,  Bosshard,  another  Swiss  chemist,  describes 
the  use  of  nitric  acid  and  of  nitro-sulfuric  acid.  It  may  be  noted  that  the 
use  of  nitric  acid  in  this  connection  has  already  been  mentioned  by  Heber- 
lein  in  U.  S.  Patent  1,392,264.  The  commercial  possibilities  offered  by 
the  use  of  nitric  acid  are  small  compared  with  those  obtained  by  the  use 
of  sulfuric  acid,  and  it  is  doubtful  if  the  process  has  ever  been  successfully 
operated  on  a  large  scale.  As  a  matter  of  patent  literature,  however, 
the  work  of  Bosshard  is  interesting  and  may  be  given  as  stated  by  the 
inventor  as  follows: 

"It  is  well-known  fact  that  the  action  of  concentrated  mineral  acids  on  cotton 
fabrics  causes  the  latter  to  assume  a  transparent  parchment-like  appearance.  It  has 
been  established  that  transparent  effects  on  cotton  fabrics  may  be  obtained  by  treating 
the  fabrics  alternately  or  subsequently  with  sulfuric  acid  of  from  49°  to  51°  Be.  and 
with  concentrated  alkaline  lyes. 

"Furthermore,  it  is  already  known  to  replace  sulfuric  acid  of  from  49°  to  50°  Be. 
by  cooled  hydrochloric  acid  of  a  specific  gravity  of  1.19,  or  by  nitric  acid  of  from 
43°  to  46°  Be.,  or  by  a  zinc  chloride  solution  of  66°  Be.  at  a  temperature  of  from 
140°  to  170°  F.  or  by  a  solution  of  cupric  ammonia. 

"If  nitric  acid  of  a  concentration  of  more  than  42.3°  Bo.  (sp.  gr.  1.415)  or  sulfuric 
acid  of  a  concentration  of  more  than  49°  Be.  (sp.  gr.  1.515)  be  caused  to  act  on  cotton 


SWISS  FINISH  OR   MERCERISING   WITH  ACID  653 

a  process  takes  place  which  is  similar  to  the  mercerising  by  means  of  concentrated 
alkaline  lyes  and  wherein  a  swelling  of  the  fibers,  shrinkage  and  increase  of  strength 
takes  place.  Bleached  and  mercerised  cotton  fabrics  which  are  treated  with  such  an 
acid  assume  a  gelatinous  parchment-like  appearance  and  show  a  considerably  stronger 
affinity  to  direct  acting  coloring  matters.  According  to  Knecht/  the  treatment  with 
nitric  acid  of  42.3°  Be.  or  more  causes,  besides  a  weak  nitrification,  the  formation 
of  a  very  imstable  cellulose-ester  which  decomposes  by  the  action  of  the  water  similar 
to  an  alkaline  cellulose.  If  nitric  acid  of  a  specific  gravity  of  above  1.415  (42.3°  Be.), 
or  sulfuric  acid  of  a  specific  gravity  of  above  1.515  (49°  Be.)  is  caused  to  act  on 
bleached  or  mercerised  cotton  fabrics,  these  fabrics  assume  after  a  short  time  a  gela- 
tinous parchment-like  appearance  and  after  a  strong  tentering;  that  is,  stretching  with 
jigging  motion  of  the  treated  fabrics,  they  assume  a  transparent  appearance. 

"The  present  mvention  is  based  on  the  observation,  that  the  above  described 
gelatmous,  parchment-hke  or  transparent  effects  of  strong  nitric  acid  or  sulfuric  acid 
on  bleached  or  mercerised  cotton  fabrics  are  considerably  increased  if,  instead  of 
using  such  an  acid  separately,  a  nitro-sulfuric  acid  of  from  48°  to  50|°  Be.  and  cooled 
down  32°  F.  or  below  is  used,  that  is,  a  liquid  obtained  by  mixing  nitric  acid  of  from 
40°  to  41°  Be.  (at  a  temperature  of  60°  F.)  and  sulfuric  acid  of  from  55°  to  58°  Be. 
(at  a  temperature  of  60°  F.). 

"If  a  nitro-sulfuric  acid  cooled  down  to  32°  F.  or  below  within  the  lower  hmit 
of  minus  4°  F.  and  consistmg  of  1  part  by  volume  of  sulfuric  acid  of  from  55°  to  58°  Be. 
and  1  part  by  volume  of  nitric  acid  of  from  40°  to  41°  Be.  is  caused  to  act  upon  a 
bleached  or  mercerised  cotton  fabric,  the  fabric  assumes  after  five  seconds  a  gelatinous 
parchment-like  appearance  whereby  the  fibers  swell  and  shrink  in  the  longitudinal 
and  transverse  directions.  The  above  described  morphological  modifications  of  the 
fabric  can  be  varied  at  will  by  using  nitro-sulfuric  acids  of  different  concentration. 

"If  a  concentrated  nitro-sulfuric  acid  composed  of  for  instance  1  part  by  volume 
of  sulfuric  acid  of  57°  Be.  and  1  part  by  volume  of  nitric  acid  of  41°  Be.  is  used  strong 
parchment-like  effects  result  which,  after  a  tentering  or  stretching  with  jigging  motion 
of  the  treated  fabric,  change  over  into  transparent  effects  which  may  be  increased  by 
a  subsequent  mercerising  of  the  treated  fabric. 

"If  bleached  or  mercerised  cotton  fabrics  are  printed  on  with  reserves  the  treat- 
ment of  these  fabrics  with  concentrated  nitro-sulfiuic  acid  allows  of  obtaining  trans- 
parent pattern  effects.  It  will  be  noted  that  the  treatment  of  the  fabric  takes  place 
at  a  temperature  below  atmospheric  temperature  and  while  the  fabric  is  kept  stretched. 
By  controlling  the  temperature  and  keeping  it  low  the  character  of  the  transparent 
fabric  can  be  varied  from  a  hard  feeling  fabric  at  the  higher  temperatures  to  a  soft 
feeling  fabric  at  the  lower  temperatures.  On  the  other  hand,  if  the  concentration  be 
but  shghtly  lowered  with  a  corresponding  increase  in  the  length  of  time  required  for 
nitration  by  reason  of  the  lesser  concentration,  wool-like  effects  will  be  obtained,  the 
fabric  in  this  instance  not  being  strongly  stretched  to  allow  free  deformation  of  the 
fibers." 

In  this  same  connection  may  be  mentioned  the  work  of  C.  Schwartz,^ 
referring  to  a  process  for  converting  cotton  fabrics  into  a  material  having 
a  wool4ike  appearance.  His  process  is  based  on  a  treatment  with  starch 
and  nitric  acid. 

A  paste  is  prepared  by  heating  together  40  kilograms  of  maize  starch, 
75  liters  of  water  and  75  liters  of  acetic  acid.  The  textile  is  dressed  with 
1  Brit.  Pat.  37,459  of  1904.  ^  jj   s.  Pats.  1,400,380  and  1,400,381. 


G54  MERCERISED  COTTON 

this  paste,  dried,  treated  for  three  to  five  minutes  with  72  percent  nitric 
acid  at  a  temperature  of  60°  to  70°  F. ;  the  excess  of  acid  is  pressed  out, 
and  the  textile  material  is  passed  into  a  10  percent  solution  of  sodium 
bisulfate  and  washed  with  water. 

In  another  process  of  Schwartz  the  fiber  is  impregnated  with  a  slightly 
ammoniacal  solution  of  casein,  containing  10  percent  of  the  latter,  dried, 
and  submitted  for  some  time  to  the  action  of  formaldehyde  vapor;  it  is 
then  treated  for  two  minutes  with  75  percent  nitric  acid  at  the  ordinary 
temperature,  squeezed  or  pressed  out  and  washed.  The  yellowish  color 
of  xantho-proteid  developed  by  a  secondary  reaction  may  easily  be 
removed  by  treatment  with  weak  carbonate  of  soda. 

The  commercial  developments  of  these  processes  are  still  in  a  state 
of  growth  but  sufficient  has  been  accomplished  to  show  that  from  the  proc- 
esses described  in  the  patents  of  Heberlcin,  Bosshard  and  Schwartz 
coupled  with  the  design  and  construction  of  suitable  machines  and  acces- 
sory apparatus  to  properly  carry  out  the  processes  in  a  commercial  form 
there  is  much  to  be  hoped  for  in  the  gradual  perfection  of  a  process  of 
treating  or  finishing  cotton  fabrics  which  will  give  us  a  line  of  useful  and 
novel  fabrics  which  will  be  a  great  addition  to  the  industry.  Mercerising 
has  now  become  a  universal  and  well  established  process  in  the  converting 
of  cotton  goods  and  has  brought  into  existence  many  new  fabrics  which 
have  proven  of  great  value  and  utility.  It  is  quite  possible  that  the  new 
methods  of  treatment  which  have  here  been  outlined  may  prove  in  time 
as  valuable  as  the  mercerising  process  itself.  Wlien  we  consider  the  fact 
that  this  acid  treatment  process  also  originated  in  the  fertile  brain  of 
John  Mercer,  we  can  appreciate  in  some  measure  what  a  large  debt  the 
textile  industries,  and  all  those  other  industries  connected  therewith, 
owe  to  the  great  textile  chemist  of  seventy  years  ago. 


CHAPTER  XX 
THE  MINOR  SEED  HAIRS 

1.  Bombax  Cotton. — Besides  the  cotton  derived  from  the  ordinary 
species  of  the  cotton  plant  {Gossypium  family),  there  is  a  very  similar 
seed-hair  fiber  obtained  from  a  plant  known  as  the  cotton-tree  and  belonging 
to  the  Bombacece  family.  The  fiber  is  known  in  trade  as  vegetable  donm 
or  bombax  cotton.  It  grows  almost  exclusively  in  tropical  countries.  The 
fiber  is  soft,  but  rather  weak  as  compared  with  ordinary  cotton;  in  color 
it  varies  from  white  to  a  yellowish  brown,  and  it  is  quite  lustrous.  The 
fibers  have  a  length  of  from  10  to  30  mm.,  and  a  diameter  of  from  0.020 
to  0.045  mm.  Owing  to  its  weakness  and  lack  of  elasticity,  bombax 
cotton  is  not  used  by  itself  as  a  textile  fiber;  it  is  sometimes  mixed  with 
ordinary  cotton  and  spun  into  yarn,  but  it  is  principally  used  as  a  wadding 
and  upholstery  material. 

In  its  physical  appearance,  bombax  cotton  differs  from  true  cotton 
in  not  possessing  any  spiral  twist  and  showing  irregular  thickenings  of  the 
cell- wall;  the  fiber  usually  consists  of  one  cell,  though  occasionally  it 
may  have  two.  Unlike  true  cotton,  the  fiber  does  not  grow  directly  from 
the  seed,  but  originates  at  the  inner  side  of  the  seed-capsule. 

There  are  several  varieties  of  plants  from  which  bombax  cotton  may 
be  obtained.^     In  Brazil  it  is  obtained  from  the  Bombax  heptaphyllum 

^  Dodge  gives  the  following  list  of  plants  that  yield  so-called  vegetable  silk : 
Asclepias  syriaca  and  A .  incarnata  (milkweed) . 
Asclepias  currassavica  (platanilo  of  Venezuela). 
Bombax  ceiba. 

Bombax  cumanensis  (lana  del  tambor  of  ^'^enezuela) . 
Bombax  malabaricum. 
Bombax  munguba. 
Bombax  pubesceiis. 
Bombax  villosum. 
Calotropis  gigantea. 
Chorisia  insignis  and  C.  speciosa 

Cibotium  menziesii  (pulu  fiber,  not  a  true  vegetable  silk). 
Cochlospermum  gossypium. 
Eriodendron  anfructuosum  (commercial  kapok). 
Eriodendron  samauma. 
Epilobium  angustifolium  (fireweed) . 

Ochroma  lagopus  (balso;  also  known  as  the  corkwood  tree). 

655 


656 


THE   MINOR   SEED   HAIRS 


and  B.  ceiha,  and  the  product  is  known  as  Paina  lirnpa  or  ceiba  cotton. 
This  is  also  produced  in  the  West  Indies  and  other  parts  of  tropical  America. 
All  the  varieties  of  Bombax  cotton  are  very  similar  in  appearance 
and  properties,  and  it  is  practically  impossible  to  discriminate  between 
them  with  any  degree  of  certainty.  In  Bombax  ceiba  the  fiber  has  a  length 
of  from  1  to  1.5  cm.,  while  in  B.  heptaphyllum  the  fiber  length  is  from  2 
to  3  cm.,  being  by  far  the  longest  and  strongest  variety  of  bombax  cotton.^ 
B.  malabaricum,  of  South  Asia  and  Africa,  has  fibers  from  1  to  2  cm.  in 
length;  this  latter  is  known  in  India  as  Simal  cotton  or  red  silk-cotton.- 
Other  varieties  of  Bombax  plants  are  B.  cumanensds  of  Venezuela, 
giving  a  product  known  as  "  lana  del  tambor  ^^  or  ^' lana  vegetaW;    B. 

pubescens  and  B.  villosum 
from  Brazil;  B.  carolinum 
from  South  America;  B. 
rhodognaphalon  of  West 
Africa,  the  fiber  of  which 
is  known  as  wild  kapok 
and  is  used  largely  for  the 
stuffing  of  pillows  and 
mattresses. 

Cauto  cotton  of  Cuba 
is  the  fiber  obtained  from 
a  cotton  tree.  This  cotton 
is  of  a  slightly  yellowish 
tint;  the  best  fiber  is  of  1^ 
to  l\  in.  staple,  and  is 
said  to  be  as  strong  as  Sea- 
island  cotton.  The  plant 
is  perennial,  thus  differing 
from  the  American  cotton 
which  is  an  annual  crop. 
The  tree  grows  for  upwards  of  fourteen  years,  and  the  average  tree  yields  2 
to  3  lbs.  of  seed-cotton  the  first  year,  and  fully  3  lbs.  the  second  year; 
about  one-third  of  this  is  lint.  Attempts  have  been  made  in  Cuba  to 
grow  Egyptian  and  Sea-island  cotton  but  without  success  on  account  of 
insect  attacks. 

The  microscopical  characteristics  of  bombax  cotton  are  as  follows: 
The  fiber  consists  of  a  single  cell,  possessing  a  cylindrical  shape,  being 


Fig.  251. — Bombax  Cotton.     (Herzog.) 


1  This  fiber  is  about  the  only  variety  of  vegetable  down  that  has  ever  been  used  in 
spinning. 

-  Red  silk  cotton  is  very  similar,  though  inferior,  to  the  ordinary  kapok  of  com- 
merce, for  which  it  is  sometimes  substituted.  It  is  used  principally  as  a  stuffing 
material  in  upholstery  as  the  fiber  is  too  short  and  soft  to  be  spim 


KAPOK  657 

rather  thick  at  the  base  and  tapering  gradually  to  the  point.  The  base 
of  the  fiber  is  frequently  swollen  and  exhibits  a  lace-like  structure  (Fig.  251). 
The  cell-wall  is  usually  very  thin,  occupying  not  more  than  one-tenth 
the  width  of  the  fiber,  while  the  cuticle  is  well  developed.  The  cross- 
section  is  circular  and  not  flat,  as  in  the  case  of  cotton,  and  is  from  20-40 
microns  broad.  The  inner  canal  is  partly  filled  with  a  dried-up  proto- 
plasmic membrane. 

In  its  chemical  constitution  bombax  cotton  differs  from  ordinary  cotton 
in  containing  a  certain  amount  of  lignified  tissue,  consequently  it  furnishes 
a  yellow  coloration  when  treated  with  aniline  sulfate  or  with  iodine  and 
sulfuric  acid,  and  by  these  tests  it  may  readily  be  distinguished  from  true 
cotton.  Owing  to  its  lignified  nature  the  fibers  also  swell  but  slightly 
when  treated  with  Schweitzer's  reagent.  The  fiber  from  the  Bombax  ceiba 
is  distinguished  by  its  decidedly  yellowish  color. 

None  of  the  varieties  of  the  bombax  cottons  is  a  pure  white,  but  vary 
in  color  from  pale  yellow  to  brown.  The  paina  limpa  is  the  lightest  in 
color. 

2.  Kapok. — The  seed-hairs  of  the  Eriodendron  anfraduosum  (or  Bombax 
pentandrum)  are  very  similar  to  the  preceding  varieties  of  bombax  cotton. 
It  gives  the  product  known  in  Holland  as  kapok}     In  both  their  physical 

^  The  term  kapok  is  improperly  applied  to  a  large  number  of  sUky-fibered  plants 
which  are  similar  in  appearance,  but  widely  different  in  their  properties  and  origin. 
The  true  kapok  fiber  comes  from  the  kapok  tree  (.Eriodendron  anfraduosum) .  The 
chief  countries  of  production  are  the  Dutch  Indies  and  Java.  Kapok  and  similar 
fibers  are  grown  in  Ceylon,  British  India  and  Central  America.  Experiments  are 
being  made  in  the  raising  of  the  plant  in  German  New  Guinea  and  German  East  Africa. 
The  fiber  has  been  known  in  the  trade  for  years  and  is  imported  in  limited  quantities. 
The  kapok  tree  is  grown  extensively  in  Java  where  it  forms  great  rows  along  the  roads. 
The  following  statistics  are  given  for  the  Java  trade  in  kapok  for  the  year  1921: 

To  Exports  in  Tons, 

Holland 4,436 

Great  Britain 223 

Germany 

Elsewhere  in  Europe 327 

United  States 10,078 

Australia  and  New  Zealand 1,967 

Singapore 282 

Japan 231 

Elsewhere 41 

It  will  be  seen,  therefore,  that  the  United  States  is  the  largest  consumer  of  kapok. 
It  is  employed  principally  as  a  mattress  filler,  having  great  advantages  in  this  respect. 
It  is  very  resihent  and  very  light;  a  mattress  of  3  by  65  ft.  requires  only  17  to  20  lbs. 
of  kapok,  against  26  to  29  lbs.  of  horse-hair,  33  to  35  lbs.  of  seaweed,  or  30  to  60  lbs.  of 
straw.  Furthermore,  it  wiU  not  retain  moisture,  which  is  very  important  for  bedding 
in  moist  climates.  Kapok  mattresses  are  also  very  sanitary,  being  quite  vermin- 
proof.     With  regard  to  the  buoyancy  of  Java  kapok  it  will  carry  from  20  to  30  times 


658 


THE    MINOR   SEED   HAIRS 


appearance  and  chemical  properties  it  is  almost  impossible  to  distinguish 
between  kapok  and  ceiha  cotton.  Kapok  is  obtained  from  South  Asia 
and  the  East  Indies,  and  is  very  extensively  used  as  upholstery  material, 
and  also  for  the  stuffing  of  life-saving  belts  on  account  of  its  low  specific 
gravity.  It  is  stated  that  in  the  compressed  condition  kapok  can  support 
about  thirty-six  times  its  weight  in  water,  and  it  has  the  advantage  over 
cork  of  drying  quicldy.  Kapok  has  also  been  used  in  surgery  as  a  sub- 
stitute for  absorbent  cotton.^ 

In  the  preparation  of  kapok  the  bare  fruit  is  picked  from  the  tree  by 
the  natives  and  broken  open  by  pounding  with  mallets.  The  seed  and 
fiber  is  removed  and  dried  in  the  sun.     The  drying  process  is  carried  on 

inside  of  a  wire  netting  in 
order  to  prevent  the  fiber 
from  being  blown  away. 
Drying  by  artificial  means 
is  not  employed.  The 
fiber  is  separated  from  the 
seed  by  hand.  The  seed 
with  the  fiber  is  thrown 
into  a  basket  and  stirred 
by  hand  with  a  short  stick. 
The  heavy  seed  sinks  to 
the  bottom  and  the  fiber 
is  removed  from  the  top. 
As  will  be  readily  under- 
stood, this  is  a  slow  and 
expensive  process.  At- 
tempts have  been  made 
to  invent  a  machine  for 
removing  the  fiber,  but 
without  success  owing  to 
its  brittle  nature.  Of  late  years  there  has  been  much  adulteration  of  the 
kapok  fiber  by  mixing  with  low  grades  of  cotton  and  cotton  waste.  The 
fiber  is  packed  in  square  bales  at  a  pressure  of  150  to  450  lbs.  to  the  inch. 
The  bales  are  covered  with  jute  and  fastened  with  iron  bands.  Owing  to 
the  importance  of  kapok  cultivation  in  Java  the  planters  in  that  colony 
have  tried  to  protect  their  trade  by  marking  the  product  "  Java  kapok," 


Fig.  252. — Root  Portion  of  Kapok  Fiber.     (Herzog.) 


its  own  weight  in  water,  while  Indian  kapok  will  carry  only  10  to  15  times  its  own 
weight.  Java  kapok  also  does  not  lose  its  buoyancy  by  immersion  in  water;  on  a 
thirty-days'  immersion  test  it  lost  only  10  percent  of  its  buoyancy. 

1  The  Chemnitzer  Aktienspinnerei  of  Chemnitz,  Germany,  manufacture  kapok  into 
a  yarn  possessing  a  marked  silk-like  appearance.  The  material  may  be  dyed  in  any 
desired  color,  and  may  be  employed  in  the  weaving  of  quite  a  variety  of  fabrics. 


KAPOK 


659 


and  having  each  bale  stamped  to  indicate  the  quality  as  a  guarantee 
against  adulteration. 

Owing  to  the  inflammability  of  kapok  many  fire  insurance  companies 
have  refused  to  take  risks  on  establishments  in  which  this  material  is  used; 
others  having  accepted  the  risks  only  at  very  high  premiums.  The 
kapok  seed  yields  about  25  percent  of  oil,  which  is  used  in  the  manufacture 
of  soap.  The  seed  from  which  the  oil  has  been  pressed  is  used  for  fertilising 
the  land  and  for  feeding  cattle. 

Kapok,  on  account  of  its  great  buoyancy  and  freedom  from  water- 
logging, has  been  employed  to  a  large  extent  in  recent  years  in  the  manu- 
facture of  life-buoys,  hfe-belts,  waistcoats,  seat  covers,  and  other  appli- 
ances used  for  saving  life  at  sea. 
Java  kapok,  which  is  the  kind 
usually  specified  in  navy  re- 
quirements, consists  of  the  seed- 
hairs  of  Eriodendron  anfrac- 
tuoswn,  and,  although  this  tree 
occurs,  in  India,  most  of  the 
Indian  kapok  is  obtained  from 
the  so-called  cotton-tree,  Bom- 
hax  malabaricum,  and  therefore 
does  not  in  this  respect  meet 
the  requirements  of  most  speci- 
fications. The  seed-hairs  of 
Calotropis  procera,  known  as 
Akund  floss,  are  also  collectedir 
India,  and  sometimes  become 
mixed  with  Indian  kapok. 

In  order  to  investigate  the  question  of  the  natural  volume  of  Indian 
kapok  as  compared  with  that  of  genuine  kapok,  the  following  experiment 
was  made:  50  grams  of  floss  were  placed  in  a  cylindrical  glass  jar,  a  light 
stiff  cardboard  disk  was  then  laid  on  the  floss,  and  a  500-gram  weight 
placed  on  the  card;  after  standing  some  time,  the  height  of  the  column  of 
floss  was  measured.  The  following  figures,  given  in  the  Bulletin  of  the 
Imperial  Institute,  were  obtained  as  a  result  of  repeated  experiments: 

Natiiral 
Volume. 

Java  kapok 100 

Indian  kapok  (machine-cleaned) 125 

"          "      (commercial  sample  No.  1,  referred  to  above).    93 
Akund  floss 100 

In  experiments  to  determine  the  buoyancy  of  the  Indian  kapok  the 
results  obtained  on  a  large  scale  with  24-oz.  samples  of  floss  agreed  well 


H^ 

^^H 

w^^ 

'^l 

1 

V 

^K     £l^ 

1 

?^JM 

■■t  Sr."  V  '^ 

IHk 

^nl 

Vffi"'^ 

f 

1 

HL  ^^Jj| 

I 

/,-3l 

■i 

H 

Fig.  253. — Seed  Capsules  of  Kapok. 


660  THE   MINOR  SEED  HAIRS 

with  those  obtained  in  the  small-scale  trials,  except  in  the  case  of  the 
weights  supported  by  the  floss  after  rough  treatment.  They  indicate  that 
although  Indian  kapok  appears  to  be  liable  to  contain  more  adventitious 
matter  (e.g.,  sand,  leaf,  and  pieces  of  pod)  than  commercial  Java  kapok, 
there  is  no  apparent  ground  for  condemning  its  use  in  life-saving  apparatus 
provided  that  it  is  in  a  reasonably  clean  condition. 

Akund  floss,  on  the  other  hand,  is  distinctly  inferior  to  kapok  in 
buoyancy,  and  in  one  of  the  trials  its  buoyancy  after  twenty-four  hours' 
inmiersion  was  not  sufficient  to  meet  the  Board  of  Trade  requirements; 
further,  it  will  not  stand  rough  usage,  and  rapidly  becomes  waterlogged. 
It  should,  therefore,  be  excluded  from  use  in  life-saving  appliances,  and  its 
use  restricted  to  upholstery,  etc.,  where  buoyancy  is  not  required. 

The  use  of  kapok  and  its  substitutes  underwent  considerable  expansion 
during  the  World  War.  In  view  of  the  utilisation  of  kapok  and  other 
flosses  for  life-saving  appliances,  an  investigation  has  been  carried  out  by 
Cross  and  Be  van,  with  the  object  of  devising  a  rapid  method  for  determin- 
ing the  approximate  value  of  representative  samples.^ 

It  has  usually  been  assumed  that  the  impermeability  of  the  material 
to  water  is  due  to  the  presence  of  such  constituents  as  oil,  wax,  and  resin 
in  the  wall  of  the  fiber;  but  it  has  now  been  found  that  this  is  not  the  case. 
The  amounts  of  such  constituents  vary  considerably  in  different  samples, 
but  the  variations  do  not  show  any  correlation  with  the  resistance  of  the 
fiber  to  the  admission  of  water,  and  the  resistance  is  not  appreciably 
affected  by  the  removal  of  these  substances.  Three  tests  are  recom- 
mended for  the  rapid  determination  of  quality  in  the  laboratory.  The 
first  of  these  is  observation  of  the  degree  of  lignifi  cation  of  the  fiber  by  the 
phloroglucinol  test;  the  best  samples  do  not  give  any  reaction  with 
phloroglucinol,  but  the  lower  qualities  give  a  reddish  brown  or  even  a 
magenta-red  coloration,  typical  of  lignocelluloses.  The  second  test  consists 
in  the  microscopical  measurement  of  the  diameters  of  the  fibers;  the  more 
uniform  the  diameter,  the  higher  is  the  quality  of  the  material.  The 
third  test  is  carried  out  by  floating  the  fiber  on  the  surface  of  aqueous 
alcohol,  of  sp.  gr.  0.928,  and  determining  the  relative  rates  of  wetting 
and  sinking  of  the  different  samples.  Particulars  are  given  of  the  flotation 
and  resistance  to  submersion  of  certain  appliances  made  with  kapok. 
The  life-saving  jacket  tested  contained  700  grams  of  kapok,  and,  since  the 
average  floating  power  of  the  compressed  fiber  is  equal  to  fifteen  times  its 
weight,  the  jacket,  when  submerged,  exerts  a  lifting  power  of  10.5  kilo- 
grams. When  placed  in  water  and  partially  submerged  by  a  weight  of 
9  kilos,  the  jacket  still  supported  an  extra  load  of  1.3  kilos  after  seventy- 
two  hours;  after  one  hundred  hours  it  still  required  an  addition  of  1.0  kilo 

1  Jour.  Soc.  Dyers  &  Col,  1916,  p.  274. 


KAPOK 


661 


to  submerge  it,  and  after  one  hundred  and  ninety-two  hours  the  weight 
required  was  0.9  kilo. 

Attempts  to  spin  the  lustrous  and  attractive  fiber  of  kapok  had  been 
frustrated  by  the  extreme  brittleness  and  smoothness  of  the  fiber,  until 
the  late  Emil  Stark  of  the  Chemnitzer  Aktienspinnerei  succeeded  after 
years  of  experimenting  in  perfecting  a  process  by  which  it  became  possible 
to  spin  kapok  to  as  fine  as  8's  yarn,  cotton  count.  A  mixture  of  kapok 
and  cotton  can  be  spun  to  20's,  and  mixed  with  wool  or  silk  waste  has  been 
spun  to  lO's.  The  Stark  process  is  likewise  suited  for  spinning  fibers 
similar  to  kapok,  particularly  the  Calotropis  from  southern  Asia  and 
Africa,  and  which,  owing 
to  its  extreme  length  can 
be  worked  more  easily 
than  the  regular  kapok. 
In  the  Stark  process,  the 
fiber  is  treated  with  a  solu- 
tion, such  as  ether,  carbon 
disulfide,  and  also  with 
boiling  water.  This  treat- 
ment dissolves  the  sub- 
stances that  may  have  ad- 
hered to  the  fiber,  which 
loses  its  luster  by  reason  of 
the  resulting  shrinkage. 

When  examined  mi- 
croscopically kapok  is 
seen  to  have  a  tapering 
cylindrical  form,  the 
fiber  consisting  of  a  single 
cell  with  a  bulbous  base 

(Fig.  252).  It  is  soft  and  lustrous  but  deficient  in  elasticity,  hence  is  too 
brittle  for  purposes  of  spinning.  The  fiber  resembles  a  smooth  trans- 
parent structureless  rod,  frequently  doubled  over  on  itself  (Fig.  254). 
Like  the  bombax  cottons,  kapok  contains  lignoccllulose,  hence  gives  the 
yellowish  brown  coloration  with  iodine  and  sulfuric  acid.  The  following 
are  analyses  of  kapok  from  different  sources : 


Fig.  254.— The  Kapok  Fiber,     (Herzog.) 


Lagos  Kapok, 
Percent . 

.lava  Kapok, 
Percent. 

Seychelleo  Kapok, 
Percent. 

Moisture 

Ash 

Cellulose 

9.9 

2.8 

50.3 

10.9 

1.3 

63.6 

10  00 

2.08 

61.30 

662 


THE   MINOR   SEED   HAIRS 


Kapok  has  a  very  wide  lumen  in  contrast  with  a  very  thin  wall.     It  is 

very  brittle  and  cracks 
easily.  As  a  result  kapok 
is  easily  broken  when  sub- 
jected to  the  spinning  pro- 
cess, owing  to  the  pressure 
and  twisting  to  which  it 
is  necessarily  subjected. 
The  Calotropis  fiber  has  a 
similar  structure,  but  ex- 
hibits more  distinct  longi- 
tudinal lines  (Fig.  255). 
In  a  mixture  of  kapok 
and  cotton  under  the  mi- 
croscope (Fig.  256),  the 
wide,  transparent  and 
structureless  kapok  fiber 
is  easily  distinguished 
from  the  cotton.  A  mix- 
ture of  the  two  is,  there- 
fore, readily  detected, 
an  average  of  0.7  in.,  and 

a  diameter  of  0.0012  to  0.0014  in.     It  has  a  beautiful  silk-like  luster,  is 

yellowish  brown  and  very  light. 

Small  tufts  of  the  material  are 

whirled  in  the  air  at  the  slight- 
est draft.      The   cross-section 

of  the  fiber  is  generally  circu- 
lar or  oval  in  form  (Fig.  257), 

with   a  very  thin   wall.     The 

resistance  of   the   thin  wall  to 

natural    conditions    is    fairly 

high,  but  it  offers  less  resistance 

to  the  wear  and  tear  of  working 

into  yarn.     The  cross  section 

sometimes  shows  the  fiber  to  be 

flattened,  a  result  of  unripe  or 

dead  fibers.  The  Calotropis  fiber 

has  a  length  of  0.7  to  1 .5  ins.  and 

a  diameter  of  0.0006  to  0.0016 

in.     In  outward  appearance  it 

is  similar  to  kapok.  The  cross- 
section  is  usually  similar  to  that  of  kapok,  being  round  and  oval. 


255 —The  Calotropis  Fiber.     (Herzog.) 


The  kapok  fiber  has  a  length  of  0.3  to  1.25  ins. 


Fig. 


256. — Mi,xed  Kapok  and  Cotton  Fibers. 
(Micrograph  by  author.) 


KAPOK 


663 


The  following  interesting  commercial  data  concerning  kapok  are  given 
in  a  U.  S.  Consular  Report:  Java  exports  about  seven-eighths  of  the  total 
export  of  kapok  from  the  East  Indies.  Although  the  greater  part  of  the 
cultivation  of  this  tree  is  native-owned,  there  are  a  number  of  estates  under 
European  management.  On  these  estates  the  kapok  tree  is  mostly  inter- 
planted  with  coco  and  coffee.  When  ready  for  export,  the  product  is 
usually  marked  with  the  name  of  the  district  of  origin.  Kapok  is  well 
suited  for  stuffing  of  mattresses,  life-belts,  bandages,  etc.,  but  is  also 
employed  for  spinning  purposes,  in  the  manufacture  of  felt  hats,  and  of 
gun-cotton.  It  absorbs  very  little 
moisture,  and,  having  a  great  buoy- 
ancy, can  carry  twenty  to  thirty 
times  its  own  weight  in  water. 

Exporters  state  that  the  United 
States  requires  first  qualities  only, 
while  medium  grades  go  to  Europe 
and  the  lowest  to  Austrafia. 

The  Soerabaya  Handelsvereenig- 
ing  recognises  the  following  broad 
descriptions:  Good,  clean,  prime 
Madura;  good,  clean,  prime Porrong; 
good,  clean,  prime  East  Java,  fair 
average  quality  of  the  crop.  A 
further  classification  is  as  follows: 
Fancy  grade,  with  a  maximum  of 
1^  percent  of  seeds  and  dirt;  a  Fig.  257. — Cross-sections  of  Kapok  Fibers, 
good  marketable    quality,    with    a 

maximum  of  5  percent  of  seeds  and  dirt;   lowest  quality,  with  a  maxi- 
mum of  6  percent  of  seeds  and  dirt. 

Exports  of  kapok  in  metric  tons  (metric  ton  =  2204  lbs.)  from  the 
Netherlands  East  Indies  to  the  principal  countries  of  destination  were 
as  follows: 


Principal  Countries  of 
Destination. 

1913, 
Metric  Tons. 

1917, 
Metric  Tons. 

1918, 
Metric  Tons. 

1919, 
Metric  Tons. 

Netherlands 

United  States 

5,028 

1,377 

25 

680 

2,110 

10,145 

125 
5,690 
1,519 
1,094 
2,537 
11,939 

50 
4,440 

34 

406 

2,.509 

9,031 

3,375 
9,110 

Great  Britain 

1,165 

Singapore  and  Penang 

Australia 

Total  exports 

1,149 

1,688 
17,082 

664 


THE   MINOR   SEED   HAIRS 


3.  Vegetable  Down. — The  hair-fibers  of  the  Ochroma  lagopus  (from 
the  West  Indies)  have  a  length  of  from  0.5  to  1.5  cm.,  and  are  thicker 
(6-7  microns)  in  the  middle  than  at  the  ends.  The  cell-wall  is  much 
thicker  than  with  bombax  cotton,  and  the  fibers  are  also  more  lignified 
than  those  of  the  latter.  The  walls  are  especially  thick  at  the  base  and 
apex  and  here  show  the  presence  of  granular  matter  (Fig.  258).  The 
color  of  the  fiber  is  dark  brown.  Vegetable  down  occurs  in  trade  as 
edredon  vegctale  or  pattes  de  lievre,  and  the  product  comes  mostly  from 
Guadeloupe  and  Martinique.     The  typical  fibers  show  a  deep  yellow 


Fig.  258. — Vegetable  Down.  {Ochroma  Lagopus.)  (X350.)  E,  Lace-like  structure 
at  base;  F,  fiber  folded  on  itself ;  P,  point  of  fiber;  C,  thin  cell-wall.  (Micrograph 
by  author.) 


color  under  the  microscope;  others  are  nearly  colorless,  flattened,  often 
much  folded,  with  indistinct  outline  and  finely  striated  surface.  The 
typical  fibers  have  a  breadth  of  25-50  microns.  The  Ouatc  vegetate  of  the 
French  trade  is  a  mixture  of  fibers  from  Bombax,  Ochroma,  and  Chorisia 
varieties.  It  is  chiefly  used  for  the  stuffing  of  mattresses,  cushions,  etc. 
The  Cochlospermum  gossypium  of  India  and  the  Chorisia  speciosa  ^ 

1  According  to  Dodge,  the  down  or  vegetable  silk  of  Chorisia  speciosa  is  said  to  be 
excellent  for  winter  mattresses  and  pillows.  The  tree  is  known  in  Brazil  as  Arvore 
de  Paina.     According  to  Spon,  the  plant  yields  a  fiber  of  which  textures  are  made 


VEGETABLE  SILK 


665 


Fig. 


and  C.  insignis  of  South  America  also  furnish  fair  qualities  of  vegetable 

down  (Fig.  259).     They 

are  known  as  Kumbi  or 

Galgal,  and  are  used  for 

stuffing  cushions.      The 

fibers  of  C.  insignis  swell 

up  when  placed  in  water. 
Pulu  fiber  can  also  be 

classed  under  the  general 

name  of  vegetable  down. 

It  is  the  hair   obtained 

from  the  stems  of  fern- 
trees,  more  especially  the 

Cibotium  glaucum  of  the 

Hawaiian  Islands.     The 

fibers  are   lustrous,  of  a 

golden-brown  color,  very 

soft,  and  not  especially 

strong.      They    have    a 

length  of  about  5   cms., 

and  are   composed  of  a 

series  of  very  flat  cells,  pressed  together  in  a  ribbon-hke  form  (Fig.  260). 

The  fiber  is  only  em- 
ployed as  an  upholstery 
material  and  is  never 
spun.  Similar  fibers  are 
also  obtained  from  Cibo- 
tium barometz,  C.  men- 
ziesii,  and  C.  chamissoi; 
the  second  one  produces 
the  best  fiber. 

The  distinction  be- 
tween fibers  of  different 
varieties  of  vegetable 
down  is  not  only  difficult, 
but  it  is  also  without  any 
special  importance. 

4.  Vegetable  Silk.— 
Another  seed-hair  which 
is  utilised  to  some  extent 
as  a  fiber  is  the  so-called 


259. — Fibers  of  Cochlospermum  Gossypium  Showing 
Air-cells  in  Lumen.    (Herzog.) 


Fig.  260. 


-Pulu  Fiber  from  Cibotium  Glaucum. 
(Herzog.) 

which  are  so  much  like  silk  in  their  luster,  fineness  and  pliability  as  to  be  scarcely 
distinguished  from  it. 


666 


THE   MINOR  SEED  HAIRS 


vegetable  silk  or  Asclepias  cotton  (Figs.  261  and  262).     Though  the  fiber 

presents  a  beautiful  silky 
appearance  it  is  entirely 
unsuited  for  the  manufac- 
ture of  textiles,  though  it 
is  both  longer  and  stronger 
than  bombax  cotton  or 
kapok. 

This  fiber  is  obtained 
from  Asclepias  syriaca  and 
A.  incarnata  or  common 
milkweed  or  silk  weed.  The 
plant  grows  extensively 
in  America.  The  surface 
fiber  from  the  seed-pods  ^ 
is  used  for  upholstery  ma- 
terial.2 

The  fiber  of  vegetable 
silk  is  quite  brittle  in 
nature  and  possesses  but 


Fig.  261. — Fibers  of  Asclepias  Vegetable  Silk. 
(Herzog.) 


1  The  same  plant  also  furnishes  a  bast  fiber  which  is  fine,  long,  and  glossy,  and 
said  to  be  equal  in  strength  and  durabiUty  to  hemp. 

-  There  have  been,  however,  spasmodic  attempts  by  individuals  to  prepare  fabiics 
from  the  silky  fiber  of  the  milkweed.  These  have  been  accomplished  by  rather 
laborious  handwork.  Dodge  in  Useful  Fiber  Plants  states  that  a  friend  in  Salem, 
Mass.,  informed  him  that  as  early  as  1862,  Miss  Margaret  Gerrish,  of  that  city,  made 
from  the  milkweed  fiber  some  beautiful  fabrics,  such  as  purses,  workbags,  socks,  and 
skeins  of  thread  which  were  dyed  in  many  colors.  It  also  seems  that  this  plant  grcws 
extensively  in  Syria,  and  the  natives  there  have  produced  some  beautiful  and  delicate 
fabrics  from  the  fiber.  These  attempts  to  utilise  the  fiber,  however,  do  not  seem  to 
have  resulted  in  any  permanent  extended  use  and  have  never  gone  beyond  the  limita- 
tions of  amateur  handwork. 

The  study  of  textile  history,  however,  indicates  that  there  have  been  serious  efforts 
made  toward  the  spinning  and  weaving  of  this  fiber,  but  that  such  attempts  have 
always  ended  in  failure.  It  seems  that  while  the  fiber  of  the  milkweed  is  beautifully 
white  and  lustrous  and  is  of  good  length  and  of  a  fineness  that  should  make  it  acceptable 
as  a  spinning  fiber,  it  possesses  other  qualities  that  completely  interfere  with  its  use 
in  this  connection.  The  fiber  is  stiff  and  brittle;  it  does  not  lend  itself  to  being  bent 
and  twisted,  a  feature  which  is  so  essential  in  the  spinning  together  of  a  number  of 
fibers  to  make  a  continuous  and  coherent  thread.  Furthermore,  the  surface  of  the 
fiber  is  extremely  smooth,  resembling  almost  a  glass  rod  in  this  respect;  it  does  not 
possess  any  irregularities  or  twists  which  would  allow  one  fiber  to  grip  on  to  another 
when  being  spun.  The  fibers  are  so  smooth,  in  other  words,  that  they  slip  on  one 
another  and  do  not  cohere,  so  that  when  twisted  together  into  a  yarn  the  thread  has 
no  strength  but  very  easily  pulls  apart  under  the  slightest  tension. 

After  it  was  found  impossible  to  produce  a  satisfactory  yarn  by  spinning  the  milk- 
weed fiber  by  itself,  attempts  were  made  to  spin  mixtures  of  it  with  other  fibers,  and 


VEGETABLE  SILK 


667 


little  tensile  strength  ;i 
proved  very  successful. 
Its  chief  physical  quali- 
ty is  its  high  degree  of 
luster  and  softness. 
When  examined  under 
the  microscope,  the  fiber 
cxhibitsthickenedridges 
(Fig.  263)  in  the  cell- 
wall  which  serve  to  dis- 
tinguish it  from  Bombax 
cotton.  These  ridges  or 
longitudinal  thickenings 
occur  from  2-5  times  in 
the  fiber;  in  some  cases 
very  distinct,  in  others 
scarcely  noticeable. 
Owing  to  these  ridges 
the  fibers  appear  to 
have  indistinct  longi- 
tudinal striations,  thus 


hence  attempts  at  spinning  it  by  itself  have  not 


Fig.  262. — Cross-sections  of  Asclepias  Vegetable  Silk. 


with  some  degree  of  success.  A  number  of  years  ago  a  French  firm  employed  it  in 
this  manner,  mixing  20  percent  of  vegetable  silk  with  80  percent  of  wool.  This  was 
found  to  yield  a  rather  serviceable  yarn  which  was  employed  in  weaving  a  special 
class  of  fabrics  known  as  "silver  cloth,"  so  called  from  the  high  silvery  luster  produced 
by  the  milkweed  fiber. 

Outside  of  its  use  as  a  spinning  material,  however,  the  milkweed  fiber  has  had 
some  degree  of  utihty  as  a  fiber  for  stuffing  pillows,  bedding  and  upholstery;  it  has 
also  been  used  as  wadding.  This  use,  however,  is  comparatively  small  and  has  not 
been  sufficient  to  encourage  the  cultivation  of  the  plant  for  industrial  purposes. 

The  milkweed,  however,  offers  other  possibilities  as  a  fiber  plant  than  that  given 
by  the  silky  fibers  from  the  seed  pods.  It  has  been  found  that  the  stalk  furnishes  a 
very  fine  quality  of  bast  fiber  somewhat  similar  in  character  to  that  of  the  flax  plant  or 
hemp.  This  bast  fiber  has  been  fairly  well  studied,  and  is  said  to  be  a  fine,  long, 
glossy  fiber  with  great  strength  and  durability.  Some  authorities  have  claimed  that 
the  yield  of  fiber  from  the  plant  is  about  equal  to  that  of  hemp.  When  compared 
with  the  hemp  fiber  it  seems  to  be  about  as  strong,  and  somewhat  finer  and  more  glossy 
in  appearance.  Some  attempts  have  evidently  been  made  in  Brazil  to  utilise  this 
bast  fiber  of  the  milkweed,  as  many  fine  samples  have  come  from  that  country,  but 
there  has  as  yet  been  no  commercial  record  of  its  use  in  manufacture.  In  India  it  is 
claimed  that  the  bast  fiber  has  been  used  for  the  weaving  of  fine  fabrics  and  also  has 
been  employed  in  paper  making,  for  which  purpose  it  should  be  eminently  adapted. 
But  notwithstanding  all  these  reports  and  statements  of  observers  the  products  do 
not  seem  to  have  come  into  commerce  sufficiently  to  have  attracted  any  attention,  so  it 
will  be  well  for  the  time  being  to  accept  such  statements  rather  as  over-enthusiastic 
intentions  than  as  actual  conditions. 

1  Vegetable  silk  is  also  unsatisfactory  for  the  manufacture  of  guncotton,  as  it  burns 
too  slowly  and  leaves  too  much  ash. 


668 


THE   MINOR  SEED   HAIRS 


distinguishing  them  from  other  seed-hairs.  Each  fiber  consists  of  a 
single  cell,  usually  somewhat  distended  at  the  base.  It  is  of  a  yellowish- 
white  color;  the  length  varies  from  10  to  30  mm.  and  the  diameter  from 
0.02  to  0.05  mm.  As  vegetable  silk  is  somewhat  lignified,  it  may  be 
distinguished  from  true  cotton  by  giving  a  yellowish  brown  coloration 
with  iodine  and  sulfuric  acid,  and  a  yellow  coloration  with  aniline  sulfate. 
Its  micro-chemical  reactions  are  very  similar  to  Bombax  cotton,  though 
with  phloroglucinol  and  hydrochloric  acid  the  latter  gives  a  dull  violet 
coloration,  while  vegetable  silk  gives  a  bright  red- 
violet  coloration. 

Some  attempts  have   been   made   to   so   alter  the 

glossy  surface  of  the  fibers  of  vegetable  silk  that  they 

may  be  spun  together  into  textile  yarns.      According 

to  Stark  ^  the  material    may  be  treated  with  alcohol, 

acetone,  carbon  tetrachloride,  gasoline,  or  with  weakly 

alkaline    solutions    of    Turkey-red  oil  or  soap  at  180° 

to  212°  F.,  with  the  result  that  the   outer  surface   of 

the   fiber   shrinks,  thus   making   the   fiber   somewhat 

rough  and  at  the  same  time  removing  the  encrusting 

materials.     The  roughened  fiber  can  then  be  spun  in 

the  ordinary   manner,    like  cotton.^     It  would    seem, 

Qu  ^\i  however,  that  this   treatment  would   take  away  from 

^  the  fiber  the  very  qualities  of  luster  and  silkiness  that 

Fig.  263. — Structure  alone  make  it  individual  and  attractive;  if  the  surface 

of  Asclepias  Silk,  were  roughened,  then  the  luster  would  be  ruined  and 

w.  Middle  portion  ^j^^  author  cannot  see  that   the   fiber  would   thus  be 

of  fiber;   qu,  cross- 


section;    I,   logitu- 


even  as  valuable  as    ordinary  cotton.     It  is  claimed, 


dinalridges- J  thin  however,  that  very  beautiful  yarns  are   made  in  this 

portions    between  fashion  and  are  employed   in  Germany  in  the  weaving 

thickened     ridges;  of  novelty  fabrics  and  decorative  materials.^ 

w,     c  e  11  -  w  a  11 .         There  are  several  minor  varieties  of  vegetable  silk, 

chief  among  which  are  the   following:    Asclepias   cur- 

rassavica  and  A.  voluhilis  from  the   West   Indies  and 

South  America;   Calotropis  gigantea  and  C.  procera  of  southern  Asia  and 

Africa;    several  species  of  Marsdenia   from    India;    Beaumontia   grandi- 

flora  from  India,  and  different  varieties  of  Strophanihus  from  Senegal. 

The  different  varieties  of  vegetable  silk  are  very  difficult  to  distinguish 
from  one  another.  They  all  possess  a  soft  feel  and  a  high  silky  luster. 
In  color  they  vary  from  almost  pure  white  to  a  slight  orange-yellow.  In 
thickness  the  fibers  usually  vary  from  35  to  60  microns,  though  occasionally 

1  Ger.  Pat.  230,142  and  230,143. 

2  See  also  Ger.  Pats.  231,940  and  231,941  for  the  dyeing  and  bleaching  of  this  fiber. 

3  See  Leipz.  Mnnats.  Text.  Inl.,  1911,  p.  137;  also  Elsdss  Text.  Blaf.,  1911.  p.  334. 


VEGETABLE  SILK 


669 


they  may  reach  80  microns, 
fiber  has  but  little  plia- 
bilit}^  or  elasticity,  hence 
is  very  brittle ;  this  is  due 
to  the  very  thin  cell-wall. 
All  varieties  exhibit  the 
thickened  ridge  in  the 
cell-wall,  which  gives  the 
fiber  the  appearance  of 
being  uneven  in  thick- 
ness. In  cross-section, 
these  ridges  are  usually 
semicircular,  though 
sometimes  flat  and  broad. 
The  cross-section  of  the 
fiber  itself  is  usually  cir- 
cular. 

The  seed-hairs  of  the 
Beaumontia  grandiflora 
(Fig.  264)  furnish  prob- 
ably the  best  variety  of 
vegetable  silk,  as  the  fiber 
is  not  only  the  most   lustrous  but 


In  length  they  varj^  from  10  to  50  mm.     The 


Fig.  264.- 


-Fibers  of  Vegetable  Silk  from  Beaumontia 
Grandiflora.     (Herzog.) 


is  also  the  most  purely  white,  and 
furthermore  it  possesses  the  greatest  tensile 
strength,  and  the  fibers  are  easily  separated 
from  the  seeds.  The  fibers  are  from  3 
to  4.5  cm.  in  length  and  from  20  to  50 
microns  in  diameter.  The  cell-wall  is  thin, 
being  about  3.9  microns  in  thickness.  At 
the  base  the  fiber  is  somewhat  enlarged 
and  the  walls  are  pierced  by  delicate 
elongated  pores  arranged  in  a  row  (Fig. 
265).  The  fibers  of  Calotropis  gigantea 
consist  of  thin-walled  colorless  cells  show- 
ing pitted  markings  at  the  base;  they  are 
from  2  to  3  cm.  in  length  and  from  12  to 
42  microns  in  diameter;  the  cell-wall  is 
from  1.4  to  4.2  microns  in  thickness.  At 
Fig.  265.— Structure  of  Vegetable  the  base  the  fiber  is  somewhat  enlarged 

S^iromBeaumorUia  Grandiflora-.  and  flattened,  though  this  formation  is  not 

0,  Root  or  base;   s,  point  or  end;  . 

q,  cross-section;  m,  middle  portion  ^^  perceptible  as  m  the  case  of  Beaumontia 

of  fiber;   w,  cell-wall;   I,  cell-wall  grandiflora. 


in  section.     (Hohnel.) 


The  fiber  of  Calotropis  gigan- 
tea (Fig.  266)   is  known  in  Venezuela  as 


670 


THE  MINOR  SEED  HAIRS 


Fig.  266. — Vegetable  Silk  from  Calotropis  gigantea.  Showing 
irregular  thickening  of  cell-wall  at  A,  and  an  air-bubble  at  B. 
Fibers  examined  in  water.     (Micrograph  by  author.) 


walls.  This  fiber  is  also 
not  so  easily  removed 
from  the  seeds  and  pos- 
sesses a  reddish  yellow 
color. 

The  Calotropis  gigan- 
tea, or  giant  asclepias, 
also  yields  a  bast  fiber 
said  to  be  of  very  superior 
quality,  somewhat  resem- 
bling flax  in  appearance 
and  of  the  same  strength. 
The  vegetable  silk  en- 
veloping the  seeds  is 
known  in  India  as  madar 
floss.  The  bast  fiber  is 
said  to  show  a  high 
degree  of  resistance  to 
moisture;  according  to 
Spon,    samples    exposed 


algodon  de  seda.  It 
is  more  yellow  in 
color  than  asclepias 
cotton.  The  fibers 
from  the  various 
species  of  Mars- 
denia  are  very  uni- 
formly cylindrical 
and  straight  (Fig. 
267).  In  length 
they  vary  from  1  to 
2.5  cm.  and  in  di- 
ameter from  19  to 
33  microns.  The 
cell-wall  has  an  av- 
erage thickness  of 
2.5  microns.  The 
^hevoi  Strophanthus 
differs  somewhat 
from  other  varie- 
ties, in  that  at  the 
base  there  occur 
pores    in   the    cell- 


FiG.  267. — Fibers  of  Vegetable  Silk  from  Marsdenia. 
(Herzog.) 


VEGETABLE  WOOL  671 

for  two  hours  to  steam  at  two  atmospheres  pressure,  boiled  in  water  for  three 
hours,  and  again  steamed  for  four  hours,  lost  only  5.47  percent  in  weight, 
whereas  flax  under  the  same  conditions  lost  3.50  percent,  manila  hemp 
6.07  percent,  hemp  6.18  to  8.44  percent,  and  coir  8.14  percent.  As  to  the 
strength  of  the  fiber,  Dr.  Wright's  tests  give  it  a  breaking  strain  of  552 
lbs.  as  compared  with  404  lbs.  for  sunn  hemp;  Royle's  tests  give  it  a 
breaking  strain  of  190  lbs.  as  compared  with  160  lbs.  for  Russian  hemp 
and  190  lbs.  for  Jubbulpore  hemp  from  Crotalaria  tenuifoUa. 

The  vegetable  silk  from  Calotropis  gigantea  is  sometimes  known  under 
the  name  of  kapok,  though  this  name  is  also  given  to  the  product  of  the 
Eriodendron  anfractuosum  and  Bomhax  pentandrum.  The  fiber  is  said 
to  have  been  made  into  shawls  and  handkerchiefs,  but  it  hardly  possesses 
sufficient  strength  to  be  spun  alone.  The  C.  gigantea  is  not  only  a  fiber 
plant,  as  it  also  yields  gutta-percha,  varnish,  dye,  and  medicinal  substances. 

The  ridges  in  the  fiber  of  Calotropis  gigantea  are  evident  in  surface  view 
only  after  a  careful  search,  but  in  cross-section  are  more  noticeable.  Here 
and  there  air-bubbles  are  present  in  the  Imnen  and  may  be  recognised 
by  their  different  refractive  power.  Often  one  of  the  ridges  is  more  or 
less  crooked.  When  treated  with  iodine-sulfuric  acid  reagent  of  suitable 
strength  the  hairs  exhibit  three  layers:  (1)  A  pale  yellow  slightly  altered 
outer  layer;  (2)  a  greenish  middle  layer  with  swollen  and  constructed 
outer  contour;  and  (3)  a  narrow  inner  tube.^ 

5.  Vegetable  wool  is  a  product  obtained  from  the  green  cones  of  the 
pine  and  fir  by  processes  of  fermentation,  washing,  and  mechanical  dis- 
integration. It  is  used  in  mixtures  with  cotton  and  wool  for  the  production 
of  yarns,  and  also  for  the  stuffing  of  mattresses,  etc.  The  yarns  prepared 
from  vegetable  wool  mixed  with  sheep's  wool  are  used  in  the  manufacture 
of  the  so-called  "  hygienic  flannels."  These  are  especially  recommended 
for  gouty  patients,  as  it  is  claimed  they  keep  the  body  uniformly  warm  and 
protect  it  from  dampness. 

^  Hanausek,  Microscopy  of  Technical  Products,  p.  70. 


CHAPTER  XXI 
ARTIFICIAL  SILKS 

1.  Classification. — Owing  to  the  high  price  and  value  of  silk  as  a  textile 
fiber,  numerous  attempts  have  been  made  to  produce  an  artificial  filament 
resembling  it  in  properties.  The  entomologist  Reaumur,  in  the  year  1734, 
in  a  memoir  on  the  history  of  insects,  appears  to  have  been  the  first  to 
look  forward  to  the  possible  preparation  of  silk  by  artificial  means.  It 
was  not  until  1884,  however,  that  the  first  commercial  process  for  the 
preparation  of  artificial  silk  was  taken  out  in  patent  form  by  the  Count 
Hilaire  de  Chardonnet.^ 

The  first  attempt  at  the  spinning  of  a  solution  of  collodion  appears 
to  have  been  made  by  Audemars  at  Lausanne.-  Further  experiments 
were  made  by  Weston  ^  and  Swan  ^  on  solutions  of  nitrated  cellulose  in 
acetic  acid.  Wynne-Powell  ^  tried  the  preparation  of  filaments  from  a 
solution  of  cellulose  in  zinc  chloride.  All  of  these  attempts  had  in  view 
the  preparation  of  filaments  for  incandescent  electric  lamps. 

The  varieties  of  artificial  silks  divide  themselves  into  the  following 
classes : 

(1)  Pyroxylin  or  collodion  silks,  made  from  a  solution  of  nitrated  cellulose  in  a 
mixture  of  alcohol  and  ether. 

(2)  Cuprammonium  or  cuprate  silks,  made  from  a  solution  of  cellulose  in  ammo- 
niacal  copper  oxide. 

(3)  Viscose  silks,  made  from  a  solution  of  cellulose  thiocarbonate. 

(4)  Acetate  silks,  made  from  a  solution  of  cellulose  acetate. 

(5)  Gelatine  silks,  made  from  filaments  of  gelatine  rendered  insoluble  by  treatment 
with  formaldehyde.^ 

^Brit.  Pat.  6045  of  1885. 
2jBn/.  PaL  283  of  1855. 
^Brit.  Pat.  of  September  12,  1882. 
^  Ger.  Pat.  30,291  of  1884. 

5  Bnt.  Pat.  of  December  22,  1884. 

6  Artificial  Silk  Jroni  Milk. — A  recent  British  patent  describes  the  following  method 
for  the  manufacture  of  artificial  silk.  Milk  is  treated  with  sodium  pyrophosphate 
in  the  proportion  of  3  grams  of  the  latter  to  1  liter  of  milk.  This  mixture  is  allowed 
to  stand  for  some  time,  when  the  casein  separates  as  a  jelly-like  mass.  The  whey  is 
run  off  and  the  casein  is  converted  into  a  tough  plastic  mass  by  adding  a  small  quantity 
of  alkali.  This  is  redissolved,  the  solution  is  filtered,  and  again  precipitated  by  the 
addition  of  acid.     The  resulting  product  is  pressed  free  from  water,  and  then  kneaded 

672 


CLASSIFICATION  673 

With  the  exception  of  the  last  class,  all  of  these  so-called  silks  are 
filaments  of  cellulose,  resolidified  from  various  kinds  of  solutions,  hence 
it  has  been  proposed  to  give  to  these  fibers  the  general  name  of  lustra- 
cellulose  as  one  more  descriptive  of  their  true  nature.^ 

From  the  term  "  artificial  silk,"  it  might  be  reasonably  supposed  that 
the  substance  so  designated  is  the  same  in  composition  and  nature  as  the 
fiber  derived  from  the  silkworm,  but  made  by  chemical  or  other  artificial 
means.  This  is  not  the  case,  however,  and  the  term  "  artificial  silk  "  is 
rather  a  misleading  one  in  this  sense.  The  name  in  reality  stands  for  a 
fiber  resembling  in  its  luster  and  general  appearance  the  true  silk  of  nature; 
but  the  identity  goes  no  further  than  this ;  for,  in  its  chemical  composition 
and  properties,  artificial  silk  is  entirely  distinct  from  that  produced  by  the 
silkworm.  It  would  be  better  to  call  the  artificial  product  "  imitation 
silk,"  or  give  it  some  name  more  distinctive  of  its  origin  and  true  nature, 
such  as  the  term  "  lustra-cellulose,"  proposed  by  Cross  and  Bevan.  The 
latter  term  is  especially  adapted  to  the  product  in  question,  for  the  dif- 
ferent varieties  of  this  fiber  which  have  acquired  any  degree  of  technical 
importance  are  all  made  from  cellulose  derivatives,  and  their  chief  quality 
is  their  high  degree  of  luster. 

with  a  little  ammonia.  After  standing  for  a  time  the  mass  becomes  transparent  and 
glossy,  and  can  be  drawn  out  into  fine  threads,  which  may  be  coagulated  by  treat- 
ment with  formaldehyde. 

A  rather  imusual  variety  of  artificial  silk  is  that  described  by  L.  Drut  in  Fr.  Pat. 
509,723.  Air  or  gas  bubbles  are  introduced  into  viscose  solution,  cellulosic  cupro- 
ammoniacal  solution,  collodium,  glue,  cellulose-acetate,  etc.,  in  order  to  obtain  a 
textile  which,  instead  of  being  filled,  is  entirely  or  partially  hollow.  The  emulsion 
thus  formed  is  spun  so  that  yarns  are  produced  in  which  the  cylinder  is  partially  or 
entirely  hollow. 

1  Of  the  several  methods  of  making  artificial  silk,  probably  the  most  economical 
one  is  the  viscose  process.  The  collodion  method  at  first  enjoyed  great  success  and 
factories  working  by  this  process  in  past  years  have  made  large  profits;  but  owing  to 
the  high  cost  of  the  alcohol-ether  solvent  employed,  it  would  not  seem  that  this  process 
could  compete  with  the  viscose  method.  The  cuprammonium  process  also  seems  to 
be  doomed,  for  though  companies  operating  under  this  process  have  also  made  large 
profits,  they  have  mostly  taken  up  the  viscose  method.  With  the  present  high  prices 
obtained  for  artificial  silk,  however,  (1922)  it  is  possible  to  manufacture  the  product 
by  any  one  of  these  three  processes  at  a  good  profit.  Under  conditions  of  rigorous 
competition,  however,  it  would  seem  from  an  economic  point  of  view  that  the  viscose 
process  would  be  the  only  one  that  stood  a  chance  of  permanently  surviving,  unless 
very  radical  improvements  are  made  in  the  cost  of  manufacture  under  the  other  two 
methods.  From  data  obtained  in  1917  of  the  factory  costs  of  the  three  varieties  of 
artificial  silk,  the  following  figures  were  derived: 

Cost  per  Pound. 

Viscose  silk $0.67 

Cuprate  silk 1.05 

Chardonnet  sUk 1-31 

It  is  highly  probable  that  the  same  ratio  of  costs  holds  even  at  the  present  time. 


674  ARTIFICIAL  SILKS 

The  majority  of  the  lustra-cellulose  used  in  trade  at  the  present  time 
falls  under  the  first  three  classes  of  silks.  The  pyroxylin  silk  represents 
the  oldest  method  employed  for  the  manufacture  of  this  interesting  fiber; 
and  there  are  three  chief  processes  by  which  this  silk  is  made,  known  by 
the  names  of  the  respective  inventors :  Chardonnet,  du  Vivier,  and  Lehner. 
All  of  these  processes  use  a  solution  of  nitrated  cellulose  as  a  base,  and 
employ  the  same  general  mechanical  idea  to  produce  the  filaments  of  the 
fiber,  the  principle  being  to  force  a  solution  of  nitrated  cellulose  through  a 
fine  capillary  tube,  coagulate  the  thin  stream  of  solution  thus  obtained, 
and  finally  denitrate  and  reel  the  thread  of  filaments  so  obtained.  As 
previously  described,  cellulose,  on  treatment  with  nitric  acid,  can  be  made 
to  yield  a  series  of  nitrated  celluloses,  the  exact  compound  obtained  being 
dependent  upon  the  conditions  of  treatment. 

Artificial  silk  is  chemically  unlike  natural  silk  and  differs  in  most  of  its 
physical  properties  so  that  there  has  not  been  direct  competition  between 
the  two  fibers.  The  high  luster  of  artificial  silk,  which  is  generally  superior 
to  that  of  the  natural  product,  and  its  lower  price  have  enabled  it  to  fill  a 
heretofore  unoccupied  place  between  mercerised  cotton  and  natural  silk. 
It  is  10  to  20  percent  heavier  than  natural  silk,  has  from  one-third  to  one- 
half  its  elasticity,  and  from  one-half  to  two- thirds  its  breaking  strength.^ 
While  natural  silk  is  practically  unaltered  by  contact  with  water,  artificial 
silk  swells  rapidly  and  loses  about  60  percent  of  its  strength,  so  that  it 
must  be  handled  with  care.  However,  by  combination  with  other  textile 
fibers  in  making  fabrics  subject  to  wetting,  this  weakness  is  overcome  to  a 
great  extent.  There  has  been  difficulty  in  obtaining  uniform  results  in 
dyeing  artificial  silk,  which  has  served  to  restrict  its  use  for  some  purposes. 

The  field  of  usefulness  of  artificial  silk  is  restricted  only  by  the  physical 
limitations  of  the  fiber.  Originally  inflammable,  weak,  and  liable  to 
severe  injury  by  water,  it  was  at  first  used  only  in  the  manufacture  of 
braids  and  millinery  and  dress  trimmings,  for  which  it  has  now  practically 

1  Rosenzweig  (American  Silk  Journal)  makes  some  interesting  statements  concern- 
ing artificial  silk  and  its  relation  to  natural  sUk.  Artificial  sUk  is  the  only  thread 
made  by  man  that  is  really  "spun,"  for  "spinning"  is  derived  from  the  German 
"spinnen,"  the  work  of  the  "spinne"  (spider),  which  forms  a  practically  endless  thread. 
All  other  threads  are  not  really  "spun,"  but  "thrown,"  that  is,  formed  by  the  method 
of  twisting  short  fibers  round  each  other.  Therefore,  real  silk  and  artificial  silk  are  the 
only  "one  piece"  threads  in  the  world,  while  all  the  others  consist  of  little  pieces 
twisted  together.  The  brilliancy  and  smoothness  of  artificial  sUk  is  even  superior  to 
the  real  silk;  it  is,  in  fact,  too  smooth  and  brilliant.  Its  great  smoothness  is  positively 
a  drawback,  as  this  will  always  remain  a  hindrance  to  forming  a  well  closed  fabric. 
In  another  respect,  however,  the  smoothness  is  an  advantage,  as  the  material  does 
not  easily  retain  dirt  and  is  easily  cleaned.  The  space  taken  by  85  ozs.  of  real  silk 
requires  100  ozs.  of  artificial  silk  to  fill;  this  means  that  the  latter  is  20  percent  less 
in  covering  power,  and  in  comparative  price,  artificial  silk  at  $2.80  would  mean  .fS.SS 
as  compared  with  real  sUk. 


COLLODION  OR  CHARDONNET  SILK 


675 


superseded  natural  silk.  As  now  manufactured,  artificial  silk  is  no  more 
inflammable  than  cotton  and  some  varieties  are  entirely  fire-resistant. 
It  is  strong  enough  to  be  handled  by  textile  machinery  either  as  warp  or 
filling  or  both,  and  much  progress  has  been  made  in  making  it  resistant 
to  water.  In  this  country  the  hosiery  industry  is  the  largest  consumer, 
while  in  the  last  few  years  the  production  of  sweaters  and  other  knitted 
goods  has  been  important.  Artificial  silk  is  woven  with  natural  silk, 
cotton  or  other  fiber  into  dress  goods,  such  as  satins  and  fancy  silks,  and 
shirtings  and  tapestry.  Plushes,  carpets,  and  imitation  furs  are  now 
made  of  artificial  silk,  and  many  kinds  of  fringes,  tassels,  and  novelties. 
It  is  of  value  in  the 
manufacture  of  gas 
mantles,  elastics, 
shoe  laces,  and  other 
articles  of  minor  im- 
portance, and  during 
the  War  it  was  used 
to  a  limited  extent 
to  make  powder 
bags  and  parts  of 
gas  masks. 

2.  Collodion  or 
Chardonnet  Silk. — 
This  is  prepared 
from  nitrated  cellu- 
lose dissolved  under 
pressure  in  a  mixture 
of  alcohol  and  ether. 
The  solution  is  co- 
agulated by  passage  Fig.  268.— Chardonnet  or  Collodion  Silk.  (X350.)  (Micro- 
through  water,  and  graph  by  author.) 
is     subsequently 

denitrated  by  a  treatment  with  dilute  nitric  acid,  chloride  of  iron,  and 
ammonium  phosphate.  It  forms  a  glossy,  flexible  fiber,  possessing  the 
peculiar  feel  and  scroop  of  true  silk. 

Many  attempts  have  been  made  to  reduce  the  cost  of  the  collodion  and 
to  obtain  other  solvents  for  the  nitrated  cellulose.  Bronnert  in  1895 
brought  forward  a  process  of  making  collodion,  based  on  the  solubility  of 
tetranitrated  cellulose  in  alcoholic  solutions  of  certain  salts,  such  as 
calcium  chloride,  ammonium  acetate,  and  ammonium  sulfocyanide. 
The  explanations  advanced  for  these  reactions  are  rather  uncertain.  It 
may  be  supposed  that  the  ammonium  acetate  produces  a  hydrolysis,  the 
ammonium  sulfocyanide  a  partial  denitration  of  the  tetranitrated  cellulose, 


676  ARTIFICIAL  SILKS 

and  the  calcium  chloride  an  alcoholic  derivative  of  the  cellulose,  which 
could  well  be  an  ethoxy-derivative,  if  the  opinion  of  Dr.  Bronnert,  "  that 
the  body  designated  by  the  name  of  tetranitrated  cellulose  is  a  tetranitrated 
oxy cellulose,"  is  correct.  The  different  compounds  thus  formed  would  be 
soluble  in  alcohol.^ 

When  first  prepared,  pyroxylin  silks  were  very  inflammable,  which 
led  to  their  being  regarded  with  disfavor.  The  processes  of  denitration, 
however,  have  now  rendered  them  even  less  inflammable  than  ordinary 
cotton  .2 

The  pyroxylin  emplojj'ed  for  the  production  of  Chardonnet's  silk  may 
be  prepared  from  either  wood-pulp,  cotton,  ramie,  or  other  source  of 
pm-ified  cellulose.  The  nitrocellulose  prepared  from  wood-pulp  (sulfite) 
gives  a  more  fluid  solution  when  dissolved  in  the  alcohol-ether  solvent, 
but  the  fiber  obtained  after  spinning  is  inferior  in  tensile  strength,  and  is 
said  to  have  less  luster  and  purity  of  color  than  filaments  produced  from 
cotton  as  the  source  of  cellulose.  As  there  are  several  nitrated  compounds 
of  cellulose  soluble  in  the  alcohol-ether  mixture  (which  is  employed  as  the 
pyroxylin  solvent),  and  as  it  is  difficult  to  obtain  satisfactory  separations 
of  the  individual  compounds,  it  is  probable  that  the  pyroxylin  contains 
penta-,  tetra-,  tri-,  and  di-nitrated  cellulose,  the  tetra-  and  tri-nitrated 
compounds  probably  occurring  in  larger  amounts.  The  preparation  of  a 
pyroxylin,  suitable  for  use  in  the  making  of  Chardonnet  silk,  as  pre- 
scribed by  Wj^ss-Naef,  cafls  for  a  nitrating  mixture  of  15  parts  of  fuming 
nitric  acid  (sp.  gr.  1.52),  with  85  parts  of  commercial  sulfuric  acid.  For 
4  kilograms  of  cellulose  about  35  liters  of  this  acid  mixture  are  required, 
and  the  time  of  action  is  from  four  to  six  hours.  Samples  are  examined 
from  time  to  time,  with  the  micro-polariscope  in  order  to  ascertain  the 
degree  of  nitration,  and  when  all  the  fibers  appear  of  a  uniform  bright 
blue  color  under  the  polariscope  the  action  of  the  acid  mixture  is  discon- 
tinued. The  excess  of  acid  is  removed  from  the  fiber  by  means  of  a 
hydraulic  press,  after  which  the  nitrated  cellulose  is  washed  for  several 
hours  with  water  and  then  pressed  again,  until  the  mass  contains  only 
about  30  percent  of  water.  At  first  the  pyroxylin  so  prepared  was  dried 
before  being  dissolved  in  the  alcohol-ether  solvent,  but  it  was  subsequently 
discovered  that  a  better  solution  could  be  obtained  by  using  the  pyroxylin 
containing  the  amount  of  water  above  noted.  This  form  of  pyroxylin  has 
been  called  by  Chardonnet  "  pyroxylin  hydrate,"  but  it  is  doubtful  if  the 
substance  is  a  true  hydrate.     However,  it  appears  to  be  about  25  percent 

1  See  Bernard,  Mon.  Scientif.,  May,  1905. 

^  Anti-phlogin  is  the  trade-name  of  a  mixture  used  for  the  purpose  of  overcoming 
the  inflammable  nature  of  artificial  silk.  It  consists  of  boric  acid,  phosphate  of 
ammonia,  and  acetic  acid.  Pyroxylin  steeped  in  this  solution  is  said  to  be  incom- 
bustible. 


COLLODION  OR  CHARDONNET  SILK  677 

more  soluble  than  the  dry  pyroxylin.  The  solvent  employed  for  the 
pyroxylin  formerly  consisted  of  a  mixture  of  40  parts  of  95  percent  alcohol  ^ 
with  60  parts  of  ether,  and  100  parts  of  this  liquid  would  dissolve  about 
28  to  30  parts  of  pyroxylin.  The  collodion  so  produced  is  filtered  several 
times  under  pressure,  in  order  to  free  it  from  all  non-nitrated  and  undis- 
solved fibers,  and  to  obtain  a  perfectly  clear  and  homogeneous  solution. 
This  condition  is  a  very  essential  one  for  the  successful  production  of  the 
silk,  as  any  irregularity  in  the  solution  would  cause  a  break  in  the  con- 
tinuity of  the  spun  filament  or  a  stoppage  of  the  machine.  The  pyroxylin 
requires  from  fifteen  to  twenty  hours  for  complete  solution,  and  that  pre- 
pared from  cotton  requires  a  longer  time  to  dissolve  than  that  from  wood- 
pulp.  In  order  to  properly  filter  the  solution  a  pressure  of  30  to  60  atmos- 
pheres is  necessary.  A  rather  recent  improvement  in  the  making  of 
collodion  silk  is  to  dispense  with  the  ether  in  the  solvent,  using  a  mixture 
of  alcohol  and  calcium  chloride  to  dissolve  the  di-nitrocellulose  (Bronnert). 
This  is  far  more  economical  and  reduces  the  fire  and  explosive  risks. 

The  next  operation  in  the  manufacture  of  the  silk  is  purely  a  mechani- 
cal one,  and  yet  one  which  has  required  the  use  of  considerable  ingenuity 
and  skill.  The  object  is  to  force  the  collodion  solution  through  very 
fine  capillary  glass  tubes,  so  that  it  may  be  drawn  thence  as  a  fine  con- 
tinuous filament.  The  collodion  solution  is  quite  viscous,  and  requires 
a  pressure  of  from  40  to  50  atmospheres  to  force  it  through  capillaries  of 
0.08  mm.  diameter.  As  the  solutions  of  nitrated  cellulose  possess  great 
viscosity,  it  is  difficult  to  prepare  a  very  concentrated  solution.  The 
addition  of  formaldehyde  or  benzene,  however,  to  the  ordinary  solvents, 
will  increase  the  dissolving  capacity  considerably,  and  also  give  a  more 
mobile  solution.  Epichlor-  and  dichlorhydrins  also  act  as  excellent 
solvents  for  nitrated  cellulose,  being  capable  of  dissolving  it  in  any 
proportion. 

The  flow  of  solution  and  pressure  must  be  so  adjusted  and  capable  of 
regulation  as  to  provide  a  uniform  filament,  and  this  involved  many 
mechanical  difficulties,  which  wei'e  only  overcome  after  long  experimenting 
and  numerous  failures.  We  will  not,  however,  at  this  point  enter  into 
a  consideration  of  the  various  mechanical  devices,  ingenious  though 
they  are,  which  have  been  perfected  for  the  proper  spinning  and  handling 
of  this  artificial  fiber.^ 

An  outline  of  the  methods  employed  in  the  practical  manufacture  of 
Chardonnet  silk  is  as  follows:  A  good  quality  of  wood-pulp  is  carefully 
disintegrated  by  suitable  machines   (resembling  a  carding-machine),  so 

1  At  the  Besangon  works,  1  kilo,  of  finished  silk  requires  4-5  liters  of  alcoliol  in  its 
manufacture. 

2  See  Siivern,  Die  kunstliche  Seide,  Berlin,  1912,  and  Williams,  La  Soie  Artificielle, 
Paris,  1902. 


678 


ARTIFICIAL  SILKS 


as  to  separate  the  individual  fibers  as  much  as  possible.  The  purity  of 
the  original  cellulose,  which  may  be  either  cotton  or  bleached  sulfite 
wood-pulp,  is  as  important  as  its  physical  condition  before  conversion 
into  the  ester.  Previous  mercerisation  or  subsequent  hydration  of  a  cellu- 
lose before  esterifying  is  found  to  influence  greatly  the  viscosity  of  the 
resulting  solutions.  This  viscosity  is  one  of  the  most  important  factors 
in  the  spinning  process  itself  and  greatly  influences  the  quality  of  the 
thread  which  is  produced.  The  bulky,  fleece-like  mass  is  then  dried  by 
steam  heat  at  140°-160°  C,  after  which  the  heated  fibers  are  steeped  in 
a  mixture  of  concentrated  sulfuric  and  nitric  acids,  as  in  the  general 

method  of  making 
gun  cotton.  The  tem- 
perature at  which  the 
cellulose  is  converted 
into  the  ester  is  of 
great  importance,  for 
it  must  be  remem- 
bered that  cellulose 
is  by  no  means  as 
chemically  indiffer- 
ent as  is  generally 
supposed.  Cellulose, 
in  fact,  is  rather 
easily  degraded  by 
chemical  treatment, 
especially  at  elevated 
temperatures ;  the 
original  molecular 
weight  is  lowered 
and  there  is  loss  of 
chemical  and  physi- 
cal resistance.  After 
suitable  treatment  in  the  acids,  the  nitrated  cotton  is  centrifuged 
to  remove  excess  of  acid,  then  washed  until  it  contains  only  about  10  per- 
cent of  acid.  The  product  was  formerly  dried  in  special  drying-rooms, 
where  the  temperature  should  not  be  above  30°  C,  and  every  precaution 
must  be  taken  to  avoid  explosions.  The  dried  nitrated  cellulose  was 
then  dissolved  in  a  mixture  of  equal  parts  of  alcohol  and  ether,  so  as  to 
secure  a  20  percent  solution.  The  resulting  collodion  (as  the  solution  is 
now  known)  is  carefully  filtered  through  silk  sieves  in  such  a  manner  as 
to  remove  all  undissolved  fibers  or  other  foreign  matter.  The  collodion 
then  passes  to  the  spinning-machine  where  it  is  forced  through  tubes  having 
nozzles  of  glass  or  platinum  with  fine  orifices.     As  the  threads  of  collodion 


Pig.  269. — Cross-sections  of  Collodion  Silk. 
(Micrograph  by  author.) 


(X250.) 


COLLODION  OR  CHARDONNET  SILK  679 

appear  they  come  into  immediate  contact  with  a  fine  stream  of  water, 
which  removes  the  solvent  and  coagulates  the  cellulose  compound. 
Recently,  however,  methods  have  been  devised  to  spin  the  filaments 
dry  instead  of  under  water.  Several  of  the  fine  threads  are  united  and 
are  wound  on  bobbins  and  into  suitable  hanks.  The  silk  is  then  deni- 
trated  by  treatment  with  a  warm  solution  (5  to  20  percent)  of  ammonium 
sulfide,  after  which  the  hanks  are  washed  and  slightly  acidified  in  order 
to  remove  all  the  ammonium  compounds.  The  process  of  denitration 
causes  the  silk  to  lose  about  40  percent  in  weight,  though  this  is  usually 
replaced  in  part  by  proper  impregnation  with  solutions  of  metallic  salts, 
which  also  have  the  effect  of  making  the  silk  fireproof.  In  the  manufac- 
ture of  collodion  silk,  an  important  factor  is  the  recovery  of  the  solvent 
from  the  wash- waters;  owing  to  the  extreme  volatility  of  the  ether  this  is 
by  no  means  an  easy  task. 

One  of  the  most  characteristic  features  of  the  Chardonnet  process 
is  the  use  of  very  highly  concentrated  solutions  of  nitrocellulose  in  order 
to  economise  alcohol  and  ether.  The  solution  can  be  drawn  out  into 
threads  directly  into  hot  air,  especially  if  wet  and  hydrated  nitrocellulose 
has  been  used.  The  air  is  then  freed  from  water  by  cooling,  and  the  vapors 
of  alcohol  and  ether  are  condensed  by  pressure  or  other  suitable  methods. 
The  high  pressure  necessary  for  forcing  the  highly  concentrated  and  very 
viscous  solutions  through  the  extremely  fine  apertures  of  the  spinnerets 
makes  the  spinning  a  tedious  process  and  often  results  in  irregularities 
in  the  thickness  of  the  filaments.  Chardonnet  works  with  collodions 
containing  from  20  to  25  percent  of  nitrocellulose  and  forces  them  through 
apertures  of  a  diameter  of  0.08  to  0.05  mm.  The  finest  miller's  gauze 
of  natural  silk  must  be  used  for  filtering  these  solutions  to  prevent  rapid 
choking  of  the  spinnerets.  Lehner  tried  using  coarser  apertures  of 
about  0.2  mm.  and  his  solutions  contained  only  about  8  percent  of  nitro- 
cellulose. In  this  way  he  overcame  the  difficulties  due  to  high  pressure, 
but,  on  the  other  hand,  it  was  no  longer  possible  to  spin  in  hot  air  and  the 
thread  was  spun  into  water  which  absorbed  the  alcohol  and  some  of  the 
ether.  Bronnert  later  improved  the  method  bj^  omitting  the  ether  from 
the  solvent  mixture,  as  he  found  that  di-nitrocellulose  could  be  dissolved 
in  alcohol  containing  a  certain  amount  of  chloride  of  calcium.  The 
resulting  collodion  was  not  explosive  and  the  alcohol  could  be  almost 
entirely  recovered  by  spinning  the  thread  into  warm  water. 

The  thread  as  it  emerges  from  the  capillary  tube  is  rapidly  coagulated 
in  the  air  by  the  evaporation  of  the  solvent.  By  suitable  arrangement 
of  a  hood  over  the  machine  and  condensing  chambers  in  connection  there- 
with, a  large  portion  of  the  mixed  volatile  vapors  of  the  alcohol  and  ether 
employed  as  the  solvent  are  condensed  and  collected,  thus  effecting  a 
considerable  saving  in  the  amount  of  solvent  required,  and  also  mini- 


680  ARTIFICIAL  SILKS 

mising  the  danger  of  explosions  occurring.  Several  of  the  individual 
filaments  are  brought  together  into  a  single  thread  and  wound  on  spools 
in  the  manner  of  ordinary  silk.  In  this  operation  a  certain  amount  of 
adhesion  takes  place  between  the  separate  filaments,  which  considerably 
enhances  the  ultimate  strength  of  the  finished  thread.  The  thread  in 
this  form  now  consists  of  pyroxylin  or  nitrated  cellulose,  and  is  highly 
inflammable  and  otherwise  unsuitable  for  use  in  textiles. 

The  next  operation  through  which  it  passes  is  one  for  the  purpose  of 
denitrating  the  cellulose,  in  order  that  the  fiber  may  ultimately  consist 
of  what  might  be  termed  "  regenerated  "  cellulose,  the  exact  chemical 
nature  of  which  it  is  not  possible  to  state  definitely,  though  it  is  evidently 
some  form  of  cellulose.  The  denitration  is  accomplished  by  passing  the 
pyroxylin  threads  through  a  bath  of  ammonium  sulfide,  though  other 
alkaline  sulfides,  and  various  other  compounds  also,  will  effect  the  same 
result.  The  silk  in  this  condition  has  a  rather  yellow  color,  which,  how- 
ever, may  be  bleached  out  in  the  usual  manner  with  a  solution  of  chloride 
of  lime  or  sodium  h3^pochlorite.  The  fiber,  as  finally  obtained,  possesses 
a  very  high  luster,  though  it  is  somewhat  metallic  in  appearance;  it  has 
considerable  tensile  strength,  though  in  this  respect,  as  also  in  elasticity, 
it  is  considerably  below  true  silk.  The  fiber  is  also  rather  harsh  and 
brittle,  and  does  not  possess  the  softness  and  resiliency  of  natm-al 
silk.i 

Many  improvements  have  been  made  in  the  matter  of  preparing  the 
solution  of  pyroxylin  for  artificial  silk.  Bronnert  -  discovered  that  by 
using  calcium  chloride  with  alcohol  the  nitrocellulose  could  be  dissolved 
without  the  use  of  ether.  Various  other  organic  and  inorganic  salts  also 
have  the  effect,  but  the  calcium  chloride  collodion  has  been  the  most 
practical  and  has  been  used  for  a  long  time,  thus  getting  rid  of  the  trouble- 
some and  expensive  ether.  The  calcium  chloride  appears  to  bring  about 
a  condensation  product  of  the  nitrocellulose  with  the  alcohol.  Although 
solution  is  instantaneous  when  a  molecule  of  calcium  chloride  is  added  to 
a  molecule  of  tetra-nitrocellulose,  the  maximum  liquefaction  is  reached 
in  about  half  an  hour,  when  the  mixture  is  heated  to  60°  or  70°  C.  and  the 
vapor  then  cooled.  The  fluidity  of  the  solution  can  also  be  increased  by 
nearly  30  percent  if,  before  nitration,  the  cellulose  be  submitted  to  an 
energetic  hydration  by  mercerising  it,  for  example,  with  caustic  soda, 
and  then  washing  it  well  with  water.  The  nitration  of  cellulose  can  con- 
veniently be  followed  by  a  slight  bleaching  with  lime ;  the  esterification  of 
the  four  hydroxyl  groups  (OH)  seems  to  protect  the  molecule  from  sub- 
sequent oxidation.  Chardonnet  has  shown  that  if  the  cellulose  is  bleached 
with  chlorine  and  then  nitrated,  the  collodion,  manufactured  from  the 

'  See  Matthews,  Jour.  Soc.  Chem.  Ind.,  1904,  p.  176. 
2  See  Brit.  Pat.  1858  of  1896. 


COLLODION   OR  CHARDONNET  SILK  681 

nitrocellulose  thus  formed,  does  not  spin  so  well  as  if  the  treatment  with 
chlorine  had  been  omitted. 

According  to  Dulitz  ^  it  is  not  possible  to  obtain  a  product  absolutely 
free  from  all  traces  of  nitrogen  without  the  destruction  of  the  filament. 
For  practical  purposes  the  denitrated  silk  contains  about  0.05  percent  of 
nitrogen.  The  uniformity  of  denitration  is  very  important,  and  is  one 
of  the  chief  difficulties  in  the  manufacture  of  collodion  silk.  According  to 
Gorrand,^  the  addition  of  a  small  quantity  of  acetic  acid  to  the  collodion 
solution  before  spinning  accelerates  the  subsequent  denitration  process 
with  ammonium  sulfide.  Pyroxylin  silk  loses  about  8  percent  in  strength 
by  denitration.  It  is  probable  that  some  oxycellulose  is  formed  in  this 
process. 

For  the  bleaching  of  Chardonnet  silk  the  proportions  are  as  follows : 

Pounds. 

Artificial  silk 16 

Bleaching  powder 4 

Hydrochloric  acid 8 

The  bleached  skeins  are  washed  in  cold  water  to  remove  all  trace  of 
chlorine,  then  softened  with  Turkey-red  oil. 

Dulitz  3  states  that  in  the  bleaching  of  collodion  silk  the  use  of  bleaching 
powder  is  now  almost  entirely  discarded  since  it  injuriously  affects  the 
strength  of  the  fiber  and  causes  subsequent  discoloration.  Various 
peroxides  and  per-salts  have  been  tried  but  owing  to  their  high  cost,  and 
to  the  fact  that  they  tend  to  produce  a  harsh  fiber  have  not  been  generally 
adopted.  Sodium  hypochlorite  solutions  having  a  concentration  of 
0.5  gram  of  active  chlorine  per  liter  are  now  in  general  use,  often  with  the 
addition  of  sodium  carbonate  or  Turkey-red  oil.  Hydrochloric  acid  is 
mostly  used  for  souring  as  it  is  most  easily  removed  by  washing  and  gives 
a  softer  thread.  Treatment  with  soap  or  Turkey-red  oil,  without  washing, 
before  immersing  in  the  bleach  liquor  is  said  to  be  advantageous. 

In  the  collodion  process  there  are  certain  defects  readily  appreciated 
by  chemists,  especially  the  presence  of  sulfuric  acid  groups  in  the  product 
not  entirely  removed  in  the  denitration  treatment.  This  treatment  is 
not  a  simple  saponification  of  the  nitrate,  and  it  does  not  appear  to  be 
possible  to  effect  this  simple  reversal  in  the  case  of  the  nitrates  of  cellulose. 
The  treatment  with  alkali  for  such  purpose  causes  a  destructive  action  on 
the  cellulose  complex.  The  process  devised  to  avoid  this  is  one  based  on 
the  de-oxidation  of  the  acid  residues  and  combination  with  bases  to  soluble 
forms. 

^Chem.Zeit.,  1910,  p.  989. 

2  Fr.  Pat.  354,424  of  1905. 

3  Chem.  Zeit.,  1911,  p.  189. 


682  ARTIFICIAL  SILKS 

According  to  Foltzer  ^  in  the  modern  process  for  preparing  Chardonnet 
artificial  silk  the  washed  cotton  is  converted  into  nitrocellulose  by  immers- 
ing 4  kilos.  (8.816  lbs.)  of  cotton  in  35  liters  (7.7  gallons)  of  a  mixtm-e  of 
nitric  acid  and  sulfuric  acid;  the  proportions  being  15  percent  of  nitric 
acid,  specific  gravity  1.52,  and  85  percent  of  ordinary  sulfuric  acid.  The 
cotton  remains  in  the  mixture  from  four  to  six  hours,  and  the  degree  of 
nitration  depends  upon  the  time  of  immersion.  This  degree  of  nitration 
can  only  be  determined  with  a  microscope  and  by  the  aid  of  polarised 
light.  The  acid  is  afterward  pressed  out  of  the  nitrocellulose,  and  the 
latter  is  then  washed  until  no  trace  of  acid  remains.  Finally,  the  water  is 
removed  from  the  substance  by  means  of  hydraulic  presses  or  hydro- 
extractors  until  there  remains  not  more  than  36  percent  of  water.  In  this 
state  the  nitrocellulose  is  inflammable  only  to  a  slight  degree,  a  condition 
which  is  of  great  importance  for  its  ultimate  use.  To  22  kilos.  (48.5  lbs.) 
of  this  nitrocellulose  are  added  100  liters  (22  gallons)  of  a  mixture  of 
equal  quantities  of  ether  and  alcohol.  This  solution  is  then  filtered  and 
kept  in  large  reservoirs.  Experience  has  shown  that  a  solution  which  has 
been  kept  for  several  days  will  produce  a  better  quality  of  silk  than  a  freshly 
prepared  solution.  From  this  pulp  the  silk  is  afterward  spun.  For  this 
purpose  a  very  simple  apparatus  is  used,  consisting  of  a  certain  number 
of  glass  tubes,  each  drawn  out  to  a  capillary  tube  or  spinneret  with  a  bore 
varying  from  0.1  mm.  to  0.2  mm.  The  nitrocellulose  is  forced  through 
these  capillary  tubes  under  a  pressure  of  60  kilos,  per  square  centimeter 
(853  lbs.  per  square  inch).  Several  of  these  threads  are  grouped  together 
as  they  pass  through  a  guide  to  be  wound  untwisted  on  to  a  bobbin;  the 
group  corresponding  in  count  to  one  thread  of  natural  silk.  On  drying, 
these  threads  acquire  a  certain  degree  of  luster,  strength,  and  elasticity. 
The  threads  are  dried  in  a  stove  which  is  heated  to  45°  C.  (113°  F.),  and 
which  is  well  ventilated.  In  this  manner  the  alcohol  and  the  ether  still 
present  in  the  silk  are  volatilised,  and,  in  consequence,  the  degree  of 
inflammability  of  the  thread  is  lowered  considerably.  However,  in 
order  to  render  the  thread  absolutely  non-inflammable,  it  should  be  de- 
nitrated — an  operation  which  is  carried  out  in  a  bath  of  alkaline  sulfides. 
Thus  a  thread  is  produced  which  possesses  strength  and  elasticity;  its 
color  is  inclined  to  yellow,  but  the  thread  may  afterward  be  bleached  with 
chloride  of  lime. 

The  denitration  of  the  nitrated  cellulose,  previously  made  up  in  the 
form  of  hanks,  is  always  carried  out  in  a  solution  of  alkaline  hydrosulfides. 
At  Besangon,  calciimi  hydrosulfide  was  employed.  With  calcium  hydro- 
sulfide  the  thread  becomes  hard  and  brittle ;  its  strength  and  its  elasticity 
diminish  greatly.  Ammonium  hydrosulfide  denitrates  successfully  under 
the  influence  of  heat,  but  care  must  be  exercised  in  its  use,  and  its  applica- 

'  Textile  Manufacturer. 


LEHNER'S  SILK  683 

tion  is  expensive.  Another  disadvantage  is  its  odor,  which  is  very  dis- 
agreeable, although  it  is  less  dangerous  to  health  than  that  of  concentrated 
sulfuric  acid.  Magnesium  hydrosulfide  has  the  advantage  of  being 
cheaper;  it  denitrates  much  more  quickly,  and  it  yields  a  stronger  thread. 
A  mixture  of  ammonium  hydrosulfide  and  a  salt  of  magnesium  is  more 
stable  than  pure  ammonium  hydrosulfide,  and  it  does  equally  well  for  the 
purposes  of  denitration;  its  use,  however,  involves  unnecessary  expense. 

By  exercising  certain  precautions  it  is  possible  to  denitrate  with  sodium 
hydrosulfide.  In  general  it  is  best  to  denitrate  at  a  low  temperature. 
This  precaution  prevents  the  sulfur — which  at  the  moment  of  reaction 
is  liberated  by  the  oxidation  of  hydrogen  sulfide  in  presence  of  nitric  acid — 
from  being  deposited  on  the  fiber.  For  each  hydrosulfide  there  is  a 
limiting  low  temperature  at  which  the  denitration  is  rapidly  performed; 
while  at  a  still  lower  temperature  the  denitration  is  incomplete  and  pro- 
ceeds slowly. 

In  practice  it  is  unnecessary  that  the  saponification  of  the  cellulose 
ester  of  nitric  acid  should  be  accompanied  by  a  complete  reduction  of  the 
nitric  acid  produced.  For  complete  reduction  eight  molecules  of  hydrogen 
sulfide  would  be  required  for  one  molecule  of  tetra-nitrocellulose.  By 
taking  certain  precautions,  however,  the  denitration  may  be  carried  out 
with  four  molecules  of  hydrogen  sulfide.  The  greater  part  of  the  nitric 
acid  thus  formed  is  reduced,  and  the  resulting  nitrous  acid  unites  imme- 
diately with  one  of  the  bases  present.  Very  little  ammonia  is  formed. 
Ammonium  sulfide  produces,  in  small  quantities,  oxysulfide,  sulfites,  and 
thiosulfates,  which  cause  the  sulfur  to  remain  in  solution  in  the  form  of 
polysulfides.  In  this  manner  the  luster  of  the  fiber  is  not  altered  in  the 
slightest  by  the  presence  of  sulfur.  The  threads  of  the  denitrated  cellulose 
contain  only  traces  of  nitric  groups.  These  groups  are  sufficient,  however, 
for  the  identification,  by  means  of  diphenylamine,  of  artificial  silks  derived 
from  cellulose  by  this  process. 

3.  Lehner's  Silk. — A  development  of  collodion  silk  of  secondary  impor- 
tance was  associated  with  the  name  and  work  of  Lehner,  who  elaborated 
a  simplified  method  spinning  or  drawing  the  collodion  solution  to  a  thread. 
The  Chardonnet  process  of  forming  the  solidified  thread  of  cellulose  nitrate 
by  evaporation  of  the  volatile  solvents  was  replaced  by  the  method  of 
precipitation  or  coagulation  by  the  action  of  water  as  a  spinning  bath, 
which  thus  took  up  the  alcohol  and,  in  part,  the  ether  of  the  solution,  to 
be  afterward  recovered  by  evaporation.  Both  Lehner  and  du  Vivier 
appear  to  have  exercised  ingenuity  in  the  unpromising  field  of  compound 
colloids  as  the  basis  of  a  textile  thread,  using  mixtures  of  nitrocellulose  with 
protein  colloids,  oxidised  derivatives  of  drjang  oils,  and  the  like.  The 
Lehner  process  was  demonstrated  at  Bradford,  and  according  to  C.  F. 
Cross,  was  found  wanting  in  commercial  success  as  compared  with  the 


684  •  ARTIFICIAL  SILKS 

simple  and  specific  variants  of  the  Chardonnet  technique,  which  ha( 
already  been  set  forth  in  his  earlier  communications.  While  with  Char 
donnet  the  concentration  of  the  collodion  was  as  high  as  20  percent 
Lehner  used  onl}^  10  percent  solutions.  The  pressure  required  for  spinning 
was  also  considerably  reduced  by  lowering  the  viscosity  of  the  solutior 
by  the  addition  of  a  small  amount  of  sulfuric  acid.  Lehner  also  attempted 
the  use  of  natural  silk  waste  dissolved  in  glacial  acetic  acid. 

Lehner  equipped  a  factory  in  Switzerland,  but  did  not  succeed 
in  producing  a  saleable  thread  until  he  abandoned  the  use  of  all 
his  patented  modifications,  and  now  manufactiu'es  by  much  the  same 
means  as  that  of  Chardonnet,  and  the  fiber  is  very  similar  to  that  of  the 
latter.  Lehner  at  first  attempted  to  obtain  a  fiber  from  a  mixture  of 
pj^roxylin  solution  with  various  vegetable  gums  and  oils,  with  solutions 
of  cotton  in  copper-ammonium  sulfate,  and  even  with  solutions  of  waste 
silk,  itself.  None  of  these,  however,  proved  a  success,  and  he  reverted 
to  the  more  simple  solution  of  pyroxylin  in  combination  with  a  drying 
oil.  He  also  discovered  that  the  fluidity  of  the  collodion  could  be  materi- 
ally enhanced  by  the  addition  of  sulfuric  acid,  and  consequently  he  was 
able  to  work  his  solution  under  much  less  pressure  than  Chardonnet. 

4.  Other  Collodion  Silks.— There  have  been  a  variety  of  modifications 
in  Chardonnet's  method  for  the  preparation  of  the  collodion  solution 
and  the  details  of  spinning  the  filament.  Da  Vivier's  silk,  known  also  as 
"  Sole  de  France,"  was  prepared  from  a  solution  of  nitrated  cellulose  in 
glacial  acetic  acid  to  which  gelatine  was  added.  Substances  such  as  a 
solution  of  gutta  percha  in  carbon  disulfide,  glycerol,  and  castor  oil  were 
also  added.  A  coagulating  bath  of  sodium  bisulfite  was  employed  and 
the  silk  was  subsequently  denitrated  in  the  form  of  hanks.  Du  Vivier's 
silk,  however,  did  not  pass  l^eyond  the  experimental  stage,  and  is  no 
longer  on  the  market. 

Crespin  ^  has  endeavored  to  minimise  tlie  amount  of  solvent  by  dissolv- 
ing the  nitrated  cellulose  in  a  mixture  of  methyl  and  ethyl  alcohols  and  ether, 
to  which  solution  is  also  added  some  glycerol  and  castor  oil.  Cazeneuve  ^ 
has  claimed  the  use  of  acetone  as  a  solvent  for  the  nitrated  cellulose;  but  a 
filament  spun  from  an  acetone  solution  is  opaque  and  brittle.  The  sug- 
gested improvements  and  modification  of  processes  for  the  preparation  of 
collodion  silk  have  been  legion,  as  evidenced  by  the  large  number  of 
patents  taken  out  in  this  field;  most  of  these,  however,  are  worthless  or 
impracticable.'"^ 

Chardonnet  was  obliged  to  use  high  pressures  (60  kilos,  per  square 

1  U.  S.  Pat.  820,351  of  1906. 

2  Fr.  Pat.  346,693  of  1904. 

'  For  a  complete  presentation  of  this  patent  literature  consult  Siivern,  Die  kunstliche 
Seide,  1920.     Also  see  Worden,  Nitrocellulose  Industry,  1911,  pp.  454-565. 


CUPRATE  OR  CUPRAMMONIUM  SILK  685 

centimeter  and  more,  853  lbs.  per  square  inch)  in  order  to  be  able  to  force 
his  highly  concentrated  solutions  through  the  openings  of  the  capillary 
tubes.  This  pressure  increases  as  the  fluidity  of  the  collodion  diminishes, 
and  the  fluidity  diminishes  greatly  for  a  slight  increase  in  the  concentration 
of  the  collodion. 

Lehner  noted  that  concentrated  sulfuric  acid  and  hydrochloric  acid 
exercise  a  liquefying  action  on  the  collodion.  Chardonnet  observed  that 
the  addition  to  the  collodion  of  aldehyde,  ethyl-sulfuric  acid,  and  ammo- 
nium chloride,  also  produced  liquefaction.  Bronnert  noted  that  alcoholic 
solutions  of  certain  substances,  whether  organic  or  inorganic,  dissolve 
nitrocellulose  easily,  whereas  alcohol  alone  does  not.  The  degree  of 
solubility,  as  well  as  the  properties  of  the  solution,  varies  according  to  the 
substances  employed.  Besides  the  calcium  chloride  method  already  men- 
tioned, Bronnert  observed  that  alcoholic  solutions  of  ammonium  acetate 
also  dissolve  nitrocellulose  very  readily;  but  the  solutions  obtained  by  this 
means  have  not  the  necessary  viscosity  for  satisfactory  spinning.  When 
these  solutions  are  raised  to  a  high  temperature  in  a  vapor  bath  they 
become  brown  and  acquire  a  degree  of  fluidity  which  renders  them  useless 
for  the  operation  of  spinning  into  thread.  If  they  are  evaporated  on  a 
glass  plate,  the  residue  possesses  neither  coherency  nor  elasticity,  but 
crumbles  on  being  touched. 

Ammonium  sulfocyanate  dissolved  in  alcohol  has  also  the  property  of 
dissolving  nitrocellulose;  but  if  this  dissolved  substance  is  allowed  to 
remain  for  several  weeks  it  turns  into  a  gelatinous  material  of  a  yellowish 
color. 

Besides  the  processes  previously  given  of  obtaining  collodion  silk, 
there  are  other  methods  for  the  manufacture  of  this  artificial  product. 
Langhaus  employs  as  a  raw  material  a  preparation  from  cellulose  and 
sulfuric  acid.  This  process  consists  in  dissolving  cellulose  in  a  mixture  of 
concentrated  sulfuric  acid  and  phosphoric  acid,  and  treating  the  syrup 
so  obtained  with  glyceric  ether  or  ethyl  ether.  The  silk  obtained  by  this 
process  is  not  of  good  quality,  and  the  solution  is  not  very  stable,  as  it  soon 
precipitates  more  or  less  altered  cellulose.  Cadarat  uses  nitrated  cellulose, 
dissolving  it  in  a  very  complex  mixture  of  glacial  acetic  acid,  ether,  acetone, 
alcohol,  toluol,  camphor,  and  castor-oil.  This  forms  a  plastic  mass  which 
is  treated  with  some  proteid  substance,  such  as  gelatine  or  albumen  dis- 
solved in  glacial  acetic  acid.  After  spinning  the  fibers  are  treated  with 
tannin  in  order  to  render  them  elastic. 

5.  Cuprate  or  Cupramjnonium  Silk. — Lustra-cellulose  threads  are  also 
prepared  from  a  solution  of  cellulose  in  ammoniacal  copper  oxide  solution 
(Schweitzer's  reagent).  Weston,  in  1884,  used  this  solution  for  the  making 
of  incandescent-lamp  filaments;  Despeissis,  in  1890,  first  thought  of  apply- 
ing it  to  the  preparation  of  artificial  silks.     Fremery  and  Urban,  in  1897, 


686 


ARTIFICIAL  SILKS 


under  the  name  of  Pauly,  patented  the  first  practical  process  for  the 
manufacture  of  the  fiber. ^  This  silk  is  now  made  in  considerable  quan- 
tity by  several  fac- 
tories in  Europe  and 
America.  The  prod- 
uct is  known  as 
Glanzstoff,  Tubize, 
Cuprate,  Pauly^s  silk 
or  Parisian  artificial 
silk. 

Pauly's  process  in 
brief  was  as  follows: 
The  copper  solution 
is  first  prepared  by 
treating  copper  turn- 
ings with  ammonia 
in  the  presence  of 
lactic  acid  at  a  tem- 
perature of  4°  to  6°  C. 
At  the  end  of  about 
ten  days  the  intense 
blue  solution  of 
ammoniacal  copper 
oxide  is  ready  for 
use.  The  next  step  is  to  obtain  mercerised  cellulose  (cellulose  hydrate),^ 
which  is  done  by  mixing  100  parts  of  cotton  with  1000  parts  of  a  solution 
containing  30  parts  of  sodium  carbonate  and  50  parts  of  caustic  soda. 

^Brit.  PaL  28,631  of  1897. 

^  Foltzer  {Textile  Manufacturer)  states  that  in  order  to  reduce  the  net  cost,  the 
Elberfeld  factory  used  the  wood  of  bamboo  canes  as  raw  material.  The  resulting 
threads  were,  however,  very  much  inferior  to  those  obtained  from  cotton  cellulose. 
Bamboo  plants,  as  well  as  other  plants  of  the  same  class,  contain  a  large  quantity  of 
pecto-celluloses,  with  a  greater  or  less  proportion  of  lignocelluloses;  the  structure  of 
these  non-cellulosic  bodies  is  little  known.  Later,  the  above  firm  tried  solutions  made 
from  paper,  but  finally  returned  to  cotton  cellulose.  The  grading  of  cotton  is  done 
by  hand,  and  those  who  have  had  considerable  exjierience  can  judge,  by  handling  the 
material,  of  its  fineness,  length,  strength,  and  the  degree  to  which  it  may  be  drawn. 
In  the  manufacture  of  artificial  silk,  however,  the  difference  in  the  prices  of  the  raw 
materials  is  of  less  importance  at  the  present  time  than  the  maintaining  and  keeping 
in  good  repair  of  the  very  costly  capillary  tubes,  glass  bobbins,  etc.,  and,  in  general, 
the  mechanism  of  the  works.  The  manufacturers  of  artificial  silk  buy,  in  general, 
cotton  ready  prepared  for  solution,  and  they  demand  from  the  bleacher  guaranteed 
limits  of  moisture,  ash  and  grease.  The  moisture  must  not  exceed  6  percent,  and  the 
prease  and  ash  combined  not  more  than  0.4  percent.  It  is  also  wise  to  ascertain  the 
quantity  of  chloride  of  lime  which  has  been  employed  for  the  bleaching  process.  This 
quantity  is,  in  general,  5  lbs.  for  100  lbs.  of  cotton. 


Fig.  270. 


-Cuprate  or  Glanzstoff  Silk. 
graph  by  author.) 


(X3o0.)     (Micro- 


CUPRATE  OR  CUPRAMMOXIUM  SILK  687 

This  mixture  is  heated  for  3^  hours  in  a  closed  vessel  under  a  pressure  of 
2§  atmospheres.  The  mercerised  cotton  thus  obtained  is  washed,  dried, 
bleached  with  chloride  of  lime,  washed  and  again  dried;  after  which  it 
is  dissolved  in  the  ammoniacal  copper  oxide  solution.  The  solution 
(containing  7  to  8  percent  of  mercerised  cotton)  is  filtered,  settled,  and 
then  spun  through  capillary  tubes  under  a  pressure  of  2  to  4  atmospheres. 
The  thread  is  coagulated  by  passing  through  a  bath  of  acetic  acid  or  one 
containing  30  to  65  percent  of  sulfuric  acid,  at  the  ordinary  temperature. 

Ordinar}^  cellulose  dissolves  but  very  slowly  in  Schweitzer's  reagent, 
and  moreover,  the  solution  is  always  accompanied  by  oxidation  which 
changes  the  cellulose  molecule  so  that  it  is  not  fit  to  spin.  Bronnert  first 
proposed  the  use  of  cellulose  hydrate,  and  so  made  the  method  of  practical 
value. 

Friederich  prepares  stable  solutions  of  cuprammonium  cellulose  by 
dissolving  4  kilos,  of  copper  sulfate,  CuS04,  in  l|  liters  of  water,  and 
adding  2.41  liters  of  caustic  soda  of  38°  Be.  and  1  liter  of  water.  He  then 
adds  20  grams  of  dextrin,  which  are  taken  up  by  the  hydrate  of  copper 
which  is  formed,  and  200  grams  of  cut-up  cotton  fiber.  The  insoluble 
cellulose  pulp  impregnated  with  the  hydrate  of  copper  is  separated  by  the 
aid  of  a  filter-press,  and  is  mixed  with  1  liter  of  concentrated  ammonia. 
In  a  short  time  there  is  produced  a  homogeneous  solution  containing 
8  to  9  percent  of  cellulose  which  is  very  stable  owing  to  the  presence  of 
dextrin.  Mannite,  glycerol,  and  crude  cane  molasses  may  also  be  used 
in  place  of  the  dextrin.  This  solution  may  be  heated  to  30°  to  40°  C. 
without  danger  of  decomposition.^  Pawlikowski  prepares  cuprammonium 
solutions  of  cellulose  ^  by  the  aid  of  copper  oxychloride,  which  renders 
unnecessary  the  previous  hydration  of  the  cotton  with  caustic  soda,  that 
is  to  say,  mercerising  and  bleaching.  The  following  proportions  are 
recommended  for  use : 

100  grams  of  pure  cotton  linters; 

90         ' '    copper  oxychloride  (containing  44  to  57  percent  of  copper) ; 
900  cc.  of  ammonia  water  (0.93). 

Foltzer  (Textile  Manufacturer)  gives  the  following  notes  concerning 
the  preparation  of  the  cuprammonium  solution  of  cellulose:  "\rMien  ordi- 
nary cotton  is  brought  into  contact  with  Schweitzer's  reagent,  it  swells 
and  dissolves  only  so  far  as  the  solvent  acts  chemically  on  the  cotton  fiber. 
If  this  operation  is  carried  out  at  the  ordinary  temperature,  the  cellulose 
is  peroxidised,  and  the  solution  can  no  longer  be  used  for  the  manufacture 
of  artificial  silk.  If,  on  the  contrary,  the  solution  is  effected  at  a  low 
temperature,  and  if  the  copper  and  the  cellulose  are  used  in  certain  pro- 

1  Fr.  Pat.  404,372;  also  418,182  and  405,571. 

2  See  Fr.  Pat.  403,448. 


688  ARTIFICIAL  SILKS 

portions,  the  threads  obtained  possess  the  necessary  physical  properties. 
But  this  solution  takes  place  only  slowly;  in  order,  therefore,  to  avoid 
this  loss  of  time,  the  cellulose  is  prepared  by  preliminary  processes,  and 
in  such  a  way  that  a  relatively  short  time  only  is  necessary  for  the  opera- 
tion. By  a  prolonged  oxidation  of  the  cellulose  with  a  clear  solution  of 
chloride  of  lime,  a  product  is  obtained  which  dissolves  easily  up  to  8 
percent  in  a  solution  of  ammoniacal  copper  oxide.  The  thread  made 
from  this  solution  is  easily  dyed  with  basic  coloring  matters,  and  behaves 
in  this  case  as  an  oxycellulose.  In  order  to  be  more  sure  of  obtaining  a 
good  result,  the  solutions  are  made  from  cellulose  which  has  been  previ- 
ously hydrated.  This  is  done  simply  by  treating  the  cellulose  with  cold 
concentrated  caustic  soda,  and  afterwards  washing  the  soda  cellulose 
in  pure  water.  Cellulose  thus  prepared  dissolves  almost  immediately 
in  ammoniacal  copper  oxide  solution  kept  at  a  low  temperature.  It  is 
customary  to  add  to  these  solutions  a  little  antimony  and  tannin;  these 
astringent  substances  are  by  no  means  injurious  to  the  luster  of  the  thread. 
The  process  of  solution  can  be  simplified  further  by  treating,  at  a  low 
temperature,  h3'drated  cellulose  with  a  concentrated  solution  of  caustic 
soda;  the  sodic  cellulose  thus  obtained  is  then  treated  in  the  cold  with  a 
calculated  quantity  of  a  salt  of  copper,  and  the  mixture  is  dissolved  directly 
in  ammonia.  Whilst  the  h3^drated  cellulose  is  nearly  insoluble  in  ammoni- 
acal copper  oxide  solution,  it  dissolves  with  extraordinary  ease  in  the  same 
liquid  if  it  has  been  previously  hydrated  by  being  treated  first  with  a 
concentrated  solution  of  caustic  soda  and  afterwards  with  water. 

Friederich  ^  has  suggested  the  use  of  alkylamines  to  replace  the 
ammonia  in  the  preparation  of  the  copper-cellulose  solutions. 

The  passage  of  an  electric  current  through  the  liquid,  or  the  presence 
of  an  electronegative  metal  in  contact  with  the  copper,  is  said  to  facilitate 
the  solution  of  the  cellulose.  The  operation  is  carried  out  cold,  and  is 
hastened  by  the  presence  of  an  excess  of  free  copper  hydrate  or  carbonate. 
The  addition  of  caustic  soda  to  the  ammoniacal  solution  of  copper  is  also 
said  to  facilitate  the  preparation  of  more  concentrated  solutions  of  cellulose, 
proba])ly  owing  to  the  simultaneous  hydration  of  the  fiber.  The  cupram- 
monium  solution  of  cellulose  may  be  concentrated  by  evaporating  from 
it  a  large  part  of  the  ammonia  by  a  current  of  air.  In  this  manner  a 
solution  may  be  obtained  containing  10  percent  of  cellulose. 

The  cuprammonium  filament  may  also  be  coagulated  by  passing 
through  a  40  percent  solution  of  caustic  soda.  The  coagulated  thread 
is  washed  with  water,  and  the  copper  removed  by  treatment  with  an  acid 
bath  combined  with  the  action  of  an  electric  current. 

Berl  2  has  investigated  the  formation  and  properties  of  cuprammonium 
solutions  of  cellulose.  The  viscosity  of  the  solution  depends  on  the 
1  Fr.  Pat.  357,171.  '  Chein.  Zeit.,  1910,  p.  532. 


CUPRATE  OR  CXJPRAMMONIUM  SILK 


689 


previous  preparation  of  the  cellulose,  the  amount  dissolved,  and  the  age 
of  the  solution.  The  solution  wiU  rapidly  absorb  oxygen,  leading  to  the 
formation  of  oxycellulose,  which  has  little  value  for  spinning.  The  forma- 
tion of  cuprammonium  cellulose  is  said  to  be  a  colloidal  phenomenon,  the 
colloidal  portion  of  the  cuprammonium  hydrate  joining  the  cellulose  to 
form  an  adsorption  product  soluble  in  ammonia.  Bronnert  ^  notes  that 
hydrocellulose  is  practically  insoluble  in  the  cuprammonium  liquor. 

According  to  Foltzer  (Textile  Manufacturer),  the  apparatus  employed 
for  the  making  of  the  cuprammonium  solution  consists  of  a  vertical  cyhnder 
(see  A,  Fig.  271).  Small  pieces  of  pure  copper  are 
introduced  through  an  opening  (B)  into  the  cylinder 
(A).  The  empty  spaces  between  the  heaped-up 
particles  of  copper  are  filled  with  anunonia,  which 
enters  by  the  pipe  (C).  When  the  cylinder  is  full 
the  opening  is  closed,  and  an  air  pump  working  at  a 
pressure  of  about  two  atmospheres  agitates  the  solu- 
tion by  internal  circulation.  In  order  to  have  control 
over  the  action,  it  is  best  to  provide  each  cylinder 
with  a  meter  or  with  a  mercurial  gauge,  so  that  the 
quantity  of  air  passed  through  in  a  given  time  may  be 
noted.  By  Wright's  method  the  speed  of  the  air  is 
regulated  in  such  a  manner  that  in  one  hour  about 
forty  times  the  liquid  volume  is  allowed  to  pass 
through  the  column.  The  solution  remains  in  the 
cylinder  until  it  reaches  the  desired  strength,  which 
is  measured  by  a  hj-drometer.  To  this  end  a  gauge 
is  provided  through  which  a  few  centimeters  of 
copper  solution  in  ammonia  are  allowed  to  pass. 
When  the  Hquid  has  attained  the  required  degree  of  -p^^  271  ^A.nparatus 
concentration,  it  is  allowed  to  pass  through  the  open-  for  Preparing  Cu- 
ing (D)  into  a  graduated  tank,  the  exact  capacity  of  prammonium  Solu- 
which  is  known.  During  the  time  that  the  copper  oxide  tion.  (Foltzer.) 
is  dissolving  in  the  ammonia,  the  temperature  in  the 
cylinder  must  be  between  4°  and  6°  C.  This  temperature  is  regulated  by 
means  of  a  thermometer,  which  is  fixed  in  the  cj'linder  and  dips  into  the 
solution.  In  order  to  maintain  this  approximately  constant  temperature, 
the  cylinder  is  surrounded  by  a  double  cover  which  is  protected  by  insulat- 
ing materials. 

The  ammonincal  solution  of  copper  oxide  is  prepared  very  gradually, 
ajid  in  order  to  arrive  at  the  desired  densit}^  it  is  necessary  that  the  opera- 
tion should  occupy  about  eighteen  hours.     The  actual  time  occupied  may 
be  more  or  less,  influenced  as  it  is  by  the  kind  of  ammonia  used,  by  the 
1  Rev.  Gen.  Mat.  Col,  1900,  p.  267. 


690 


ARTIFICIAL  SILKS 


combined  surface  area  of  the  copper  presented  to  attack,  etc.  For  ex- 
ample, if  the  copper  has  not  been  attacked  by  a  preceding  oxidation, 
and  if  the  apparatus  is  new  and  being  used  for  the  first  time,  it  is  quite 
possible  that  the  time  required  may  be  even  thirty-six  hours.  The  time 
taken,  however,  has  no  influence  on  the  quality  of  the  solution,  provided 
the  work  is  carried  out  under  the  proper  conditions  of  temperature,  pres- 
sm-e,  and  density. 

In  some  works  the  copper  oxide  is  prepared  by  intermittent  operations 
— that  is  to  say,  after  the  apparatus  has  been  in  operation  about  three 
hours,  it  is  allowed  to  stand  for  two  or  three  hours,  and  so  on  until  the 
required  density  is  obtained.  It  is  understood  that  the  temperature 
remains  approximately  at  4°  C.  during  the  time  that  the  apparatus  is 


Fig.  272. — Installation  for  Preparing  Cuprate  Silk.     (Foltzer.) 


standing,  as  well  as  when  it  is  in  work.  To  secure  this  constant  tempera- 
ture, a  current  of  cooled  water,  coming  from  a  freezing  machine,  is  made  to 
circulate  between  the  two  covers  or  jackets  of  the  cylinder.  The  cylinder 
is  charged  with  a  fresh  supply  of  dissolved  copper  every  ten  days. 

The  ammoniacal  copper  oxide  prepared  in  the  cylinder  is  run  into  the 
graduated  reservoir,  so  that  the  quantity  may  be  determined;  then  it  is 
transferred  from  the  reservoir  to  the  mixing  tank  (C)  (Fig.  272)  for  dissolv- 
ing the  cotton.  The  mixing  tank  is  a  large  horizontal  iron  cylinder  in 
which  is  an  agitator  revolving  at  55  to  60  revolutions  per  minute,  thus 
keeping  the  ammoniacal  copper  oxide  in  motion,  and  facilitating  the 
solution  of  the  cotton.  Although  this  mixing  tank  is  situated  in  the 
basement  to  avoid  extreme  variations  of  temperature,  it  is,  in  addition, 
provided  with  a  double  cover,  in  order  that  the  solution  which  is  present 


CUPRATE  OR  CUPRAMMONIUM  SILK  691 

may,  by  cooling,  be  kept  constantly  at  the  temperature  of  4°  C.  (41°  F.). 
On  the  mixing  tank  is  a  dome  (d)  with  a  manhole  through  which  the  cotton 
is  introduced  into  the  mixing  tank.  This  opening  is  provided  with 
a  lid  or  cover  which  may  be  closed  rapidly  and  fastened  down.  When 
the  copper  oxide  dissolved  in  the  ammonia  is  in  the  mixing  tank,  and 
before  the  cotton  is  introduced,  a  very  small  quantity  of  a  solution  of 
caustic  soda  is  added  to  the  solution;  the  whole  is  stirred  for  a  minute, 
and  then  only,  while  the  agitators  are  in  motion,  is  the  cotton  introduced. 
The  usual  quantity  is  from  15.4  to  16.6  lbs.  of  cotton  for  22  gallons  of 
solution.  These  quantities,  however,  may  be  varied  according  to  the 
moisture  which  the  cotton  contains,  and  even  according  to  the  humidity 
of  the  surrounding  atmosphere. 

If  the  solution  is  properly  prepared,  the  cotton  must  be  completely  dis- 
solved, and  must  "  draw  out  "  or  spin  after  having  been  worked  seven 
hours.  It  has  been  shown  by  practice  that  the  rapidity  with  which  the 
cotton  dissolves  increases  with  its  degree  of  whiteness  or  of  bleaching;  the 
process  of  solution  may  take  even  twenty-five  hours  if  the  cotton  has  not 
been  sufficiently  bleached. 

The  degree  of  fluidity  is  of  so  much  importance  that  the  chemist  or 
director  of  the  establishment  must  test  it  himself,  and  not  leave  this 
task  to  the  foreman.  The  correct  degree  of  fluidity  may  also  be  deter- 
mined by  pouring  4  or  5  cc.  of  the  solution  into  a  glass-stoppered  bottle; 
then  by  holding  the  bottle  upside  down,  it  can  be  seen  if  the  solution 
flows  slowly  so  as  to  form  a  continuous  thread  or  thin  streak.  If,  on  the 
contrary,  the  substance  drops  or  forms  an  intermittent  thread,  it  has  not 
attained  the  degree  of  fluidity  which  is  necessary  for  spinning.  This 
degree  of  fluidity  may  also  be  determined  in  a  more  accurate  manner. 
For  example,  a  graduated  glass  tube  tapering  to  a  point  at  the  bottom 
(a  kind  of  burette)  is  filled  with  the  solution;  then  by  noting  the  time 
which  it  takes  to  run  out  a  given  quantity  of  the  different  solutions,  it  is 
possible  to  construct  a  table  of  reference  which  would  indicate  the  fluidity 
of  such  solutions.  It  is  a  good  practice  to  note  daily  the  fluidity  of  the 
solution  that  is  being  prepared  for  spinning. 

In  Linkmeyer's  process  the  cuprammonium  solution  of  cellulose  is 
coagulated  by  passage  through  a  solution  of  caustic  soda.  This  forms  a 
copper-alkali-cellulose.  This  compound  is  then  dissociated  by  treat- 
ment with  water  and  the  precipitated  copper  oxide  is  removed  from  the 
fiber  by  dilute  acid. 

In  Thiele's  process  {cellulo  silk)  a  concentrated  cuprammonium  solution 
of  cellulose  is  passed  through  wide  openings  into  a  liciuid  (NaOH  of  39°  Be.) 
which  slowly  coagulates  the  cellulose.  The  threads  are  drawn  out  to 
extreme  fineness  by  means  of  a  glass  roller  revolving  in  acid. 

The  cuprammonium  solutions  of  cellulose  are  rather  unstable,  being 


692  ARTIFICIAL  SILKS 

rapidly  precipitated  by  the  addition  of  neutral  dehydrating  agents  such  as 
alcohol,  sodium  chloride,  etc.  A  flocculent  jelly  consisting  of  cellulose 
hydrate  is  formed.  The  cuprammonium  solution  of  cellulose  is  extremely 
sensitive  to  the  action  of  oxygen  and  to  light;  the  cellulose  complex  in 
solution  is  degraded  and  the  change  is  shown  by  loss  of  viscosity  of  the 
solution. 

When  a  cuprammonium  solution  of  cellulose  is  treated  with  zinc,  the 
copper  is  precipitated  and  there  is  formed  a  colorless  solution  of  zinc 
ammonium  cellulose. 

For  the  successful  operation  of  the  cuprammonium  process  a  imiformly 

low  temperature  is 
required  anda  certain 
fixed  ratio  between 
the  amounts  of  cop- 
per, ammonia,  and 
cellulose  employed. 

Fremery  and  Ur- 
ban state  that  cellu- 
lose which  has  been 
parchmentised  by 
treatment  with  con- 
centrated sulfuric 
acid,  and  which  is 
designated  generally 
by  the  name  of 
amyloid,  dissolves 
in  ammoniacal  cop- 
per oxide  solution 
in  a  much  higher 
proportion  than  does 
Fig.  273. — Cross-sections  of  Cuprate  Silk.  (■X250.)  (Micro-  cellulose  which  has 
graph  by  author.)  ^^^     ^^^^     prepared 

under  these  condi- 
tions. Thus,  for  example,  parchment  paper  produced  by  means  of 
sulfuric  acid,  or  by  zinc  chloride,  dissolves  in  a  proportion  of  10  percent 
and  over,  A  solution  of  amyloid  of  this  nature  can  be  used  for  the 
manufacture  of  artificial  silk  of  the  same  count  as  is  made  from  a 
solution  of  cellulose.  It  will  thus  be  seen  that  hydrocellulose  dissolves 
in  a  proportion  as  high  as  that  of  cellulose  prepared  by  an  energetic 
bleaching  process.  Hydrocellulose  can  be  obtained  by  treating  pure 
cleaned  cellulose,  saj'  cotton  wadding,  with  sulfuric  acid  at  3  percent, 
pressing  it  without  washing,  and  leaving  it  in  contact  with  the  air  to  dry. 
After  the  substance  has  been  dried  completely  at  a  temperature  of  40°  C. 


CITRATE   OR   CUPRAMMOXIUM  SILK  693 

it  is  washed  and  dried  again.  For  the  economical  operation  of  the  cu prate 
process  it  is  also  necessary-  to  have  a  very  complete  recover}^  of  the  by- 
products. These  include  the  ammonia  and  the  copper  which  are  used 
in  the  manufacture  of  the  silk,  and  both  of  which  are  rather  costly,  Foltzer  ^ 
makes  the  following  comments  on  the  recover}^  of  these  by-products. 

(a)  The  first  by-product  recovered  is  the  ammonia  gas,  which  is  carried 
away  by  the  air  used  for  oxidation  in  the  formation  of  ammoniacal  copper 
oxide.  This  ammonia  vapor  is  simply  collected  in  water,  or  else  in  con- 
centrated sulfuric  acid,  with  the  formation  of  ammonium  sulfate. 

(b)  The  recovery  of  the  copper  and  of  the  ammonia  contained  in  the 
precipitating  hquids.  The  methods  of  recover}'  of  these  by-products 
differ  according  as  sulfuric  acid,  soda,  or  potash  is  used. 

Let  us  consider  first  the  method  of  recovery  of  copper  and  of  ammonia 
from  a  sulfuric  acid  solution.  The  acidulated  water  charged  \s'ith  copper 
and  ammonium  sulfate,  as  well  as  the  ver\'  weak  suKuric  acid  which  has 
been  used  for  precipitation  in  the  spinning  frame,  and  which  is  also 
charged  with  copper  and  ammonia,  is  forced  forward  bj'  a  lead  injector 
into  a  large  wooden  cistern.  In  these  c'sterns  the  copper  is  recovered 
by  immersing  bars  of  iron,  as  free  as  possible  from  rust,  into  the  acid. 
The  copper  which  is  deposited  is  removed  periodically,  dried,  and  sold; 
or  it  can  be  employed  again  in  the  manufacture  of  the  ammoniacal  copper 
oxide. 

"WTien  the  copper  has  been  thus  recovered,  preparations  are  made 
for  recovering  the  ammonia;  this  may  be  accomplished  in  several  ways; 
the  simplest  method  being  to  evaporate  the  hquid,  say  in  a  Kestner 
evaporating  apparatus,  or  else  in  a  lead-lined  cistern  pro\'ided  with  a 
steam  coQ.  The  ammonium  sulfate  is  deposited  as  the  evaporation 
proceeds,  and,  after  ha\ing  been  dried,  is  then  sold.  It  is  a  good  plan 
to  filter  the  liquid  before  evaporation  in  order  to  arrest  particles  of  iron 
oxide,  of  copper,  and  of  other  impurities  which  would  stain  the  salt. 
It  is  important  that  the  yield  of  ammonium  sulfate  should  approach  as 
nearly  as  possible  that  amount  which,  theoretically,  would  be  obtained 
from  the  quantity  of  ammonia  employed.  One  hter  (0.22  gallon)  of 
ammonia  at  20°  Be.  should  produce  870  grams  (1.9  lb.)  of  ammonium 
sulfate. 

(c)  When  the  coagulation  at  the  spinning  frame  is  effected  by  means 
of  soda  or  potash,  the  copper  is  removed  advantageously  by  electroh'sis, 
and  the  ammonia  is  obtained  by  evaporation.  R.  Linkmeyer,-  proposed 
to  recover  part  of  the  copper  bj'  the  introduction  of  flakes  of  cotton  cellu- 
lose into  the  precipitation  bath;  the  cellulose  retains  the  copper,  and  could 
be  used  for  solution  in  anm^ioniacal  copper  oxide. 

{d)  E.  Crumiere,  of  Paris,  has  suggested  a  method  of  remo\'ing  the 
1  Textile  Manufacturer.  2  fj.  p^t,  353,187. 


6&4  ARTIFICIAL  SILKS  '       -  • 

copper  from  the  threads,  and  at  the  same  time  of  recovering  the  copper 
by  means  of  an  electric  current,  as  had  ah-eady  been  proposed  in  1890 
by  Henri  Despeissis.  In  the  Crumiere  factory,  however,  the  process  is 
carried  out  as  follows:  The  removal  of  the  copper  from  the  artificial  silk 
threads  or  from  artificial  hair  is  effected  as  usual  by  the  action  of  dilute 
acid;  we  should  mention  in  passing,  however,  that  the  process  is  relatively 
long  and  costly.  As  the  threads  in  formation  lack  solidity,  they  are 
wound  on  to  bobbins  before  being  freed  from  copper;  but,  as  already 
stated,  the  action  of  the  acid  for  the  removal  of  copper  is  slow,  especially 
on  the  inner  layers  of  threads  on  the  bobbins;  in  addition,  large  quantities 
of  acid  are  required,  which  are  rapidly  used  up,  and  which  must  be  often 
renewed.  By  the  Crumiere  invention  it  is  possible  to  remove  the  copper 
almost  instantaneously,  and  with  much  smaller  quantities  of  acid.  In 
addition  to  the  quick  recovery  of  the  copper,  the  liquid  can  be  used  a 
large  number  of  times.  The  new  process  consists  in  placing  the  bobbins 
of  silk,  containing  after  precipitation  ammonia  and  copper,  into  a  bath 
filled  with  acid — for  example,  sulfuric  acid  diluted  with  water — and  in 
passing  an  electric  current  through  this  liquid.  The  threads  lose  their 
color  immediately,  the  copper  being  dissolved  by  the  acid,  and  carried 
to  the  cathodes,  where  it  is  deposited,  whilst  the  acid  employed  is  regen- 
erated continuously.  The  silk  which  has  thus  been  freed  from  copper 
is  then  washed  in  water  and  dried  under  tension.  The  Crumiere  proc- 
esses are  conducted  in  the  works  of  a  French  company  at  Flaviac 
(Ardeche)  and  at  I  lysskow  in  Poland. 

La  Societe  Anonyme  Le  Crinoid  of  Rouen  reduces  the  copper  salts 
in  the  alkaline  baths  by  adding  1^  percent  of  a  solution  of  formaldehyde 
to  the  precipitating  liquid,  which  itself  is  kept  at  a  temperature  of  40°  C. 

In  cuprate  silk  manufacture,  when  the  thread  was  spun  into  sulfuric 
acid,  the  recovery  of  the  copper  and  the  ammonia  was  rather  simple. 
The  copper  was  recovered  by  electrolysis  of  the  solution  or  more  simply 
by  treatment  with  iron.  The  remaining  solution  of  sulfate  of  ammonia 
was  mixed  with  lime  and  then  distilled  to  recover  the  ammonia.  Cuprate 
silk  spun  into  sulfuric  acid,  however,  often  presented  the  defect  of  glitter- 
ing points  or  specks  produced  by  the  pressure  exercised  by  one  layer  of 
the  freshly  precipitated  and  soft  gelatinous  thread  on  the  one  below  in 
drying,  for  shrinkage  had  to  be  prevented  by  using  an  inflexible  reel  or 
support.  If  shrinkage  were  permitted  in  the  drying  of  the  cuprate  silk 
the  luster  would  be  much  impaired  and  the  fiber  would  be  brittle.  When 
cuprate  silk  is  spun  into  a  bath  of  soda  lye,  the  recovery  of  the  copper 
and  the  ammonia  is  also  very  simple,  the  ammonia  being  expelled  by 
warming  the  lye  and  being  absorbed  in  sulfuric  acid.  The  copper 
hydroxide  is  extracted  with  sulfuric  acid  and  precipitated  in  the  form 
of  metallic  copper  by  electrolysis  or  with  iron.     While  fine  threads  may 


CUPRATE  OR  CUPRAMMONIUM   SILK  695 

easily  be  produced  with  cuprate  silk  by  spinning  into  acid,  thick  threads, 
like  artificial  horsehair  or  monofil,  cannot  be  made  in  good  quality.  The 
alkaline  spinning  process  has  proved  to  be  absolutely  necessary  for  this 
class  of  work.  The  products  made  with  soda  lye,  however,  are  not  so 
lustrous  as  those  made  with  the  acid  liquor,  also  with  the  alkaline  bath 
threads  from  apertures  of  less  than  0.2  mm.  cannot  be  satisfactorily  made. 
This  difficulty,  however,  has  been  overcome  by  using,  instead  of  soda 
lye  alone,  a  mixture  containing  cane  sugar  or  glucose  dissolved  in  soda 
tye.  This  permits  of  the  spinning  of  highly  lustrous  coarse  threads  as 
well  as  of  very  fine  threads.  On  merely  washing  the  precipitated  thread 
with  water  for  a  short  time  a  transparent  thread  of  uniform  composition 
is  produced.  The  copper  seems  to  be  in  solid  solution,  both  in  the 
sugar  and  the  cellulose  and  combined  with  both.  The  threads  can  be 
dried  and  kept  for  a  long  time  and  knitted  or  woven  without  undergoing 
decomposition;  the  solid  solution  is  decomposed  when  washed  with  more 
and  hotter  water,  the  sugar  is  washed  out  and  the  copper  hydroxide  is 
converted  into  black  oxide  of  copper.  Some  of  the  copper,  however, 
in  the  first  alkaline  bath  splits  off  and  is  reduced  to  red  cuprous  oxide  by 
the  sugar,  and  this  accumulates  in  the  bottom  of  the  spinning  vessel. 
The  copper  residues  left  in  the  threads  after  washing  are  removed,  along 
with  the  remaining  ammonia,  by  treatment  with  dilute  sulfuric  acid. 

In  the  Thiele  process  for  cuprate  silk  the  so-called  "  stretch  spinning  " 
method  was  employed,  in  which  weak  precipitants  were  used.  This 
process  was  tried  out  in  factories  at  Great  Yarmouth  in  England  and  in 
Hal  in  Belgium,  but  \\athout  good  results.  Bronnert,  however,  thinks 
that  the  fault  was  not  in  the  method  but  in  the  imperfect  manner  of 
operating,  as  the  process  has  been  quite  successful  at  Barmen,  giving  the 
so-called  "  Eagle  "  silk,  which  is  formed  by  single  fine  filaments  of  2  to  3 
deniers.  The  Thiele  process  is  notable  for  the  fact  that  no  real  precipitant 
is  used  but  only  water.  The  silk  is  spun  from  apertures  of  0.8  to  1  mm. 
diameter,  passes  through  a  column  of  water  in  suspension,  and  is  elongated 
to  a  fineness  of  about  2|  deniers.  The  ammonia  is  removed  b}'  the  water 
which  flows  out  with  the  threads,  while  the  copper  is  removed  later  by 
treatment  with  dilute  sulfuric  acid.  This  method  produces  the  finest 
threads  of  any  but  there  is  considerable  variation  in  the  count,  and  the 
luster  is  not  as  high  as  with  the  other  processes. 

Cuprate  silk  has  the  advantage  over  the  other  varieties  of  artificial  silk 
in  having  a  greater  resistance  to  water;  it  is  better  in  this  respect  than 
denitrated  nitro  silk  or  even  acetate  silk,  and  is  slightly  better  than  most 
viscose  silk.  This  superiority  of  cuprate  silk  is  only  present,  however, 
when  cotton  is  used  as  the  raw  material  for  the  preparation  of  the  cellulose 
solution.  It  is  on  account  of  its  better  resistance  to  water  that  cuprate 
silk  is  still  produced  and  is  preferred  for  certain  purposes.^ 
1  See  Bronnert,  Jour.  Soc.  Dyers  d-  Col,  1922,  p.  157. 


696 


ARTIFICIAL  SILKS 


6.  Viscose  Silk. — This  is  prepared  from  solutions  of  cellulose  thio- 
carbonate  and  is  the  principal  form  in  which  artificial  silk  is  made  at 
the  present  time,  both  in  American  and  Europe.^ 

Viscose  itself  is  prepared  by  the  action  of  caustic  alkali  and  carbon 
disulfide  on  mercerised  cellulose,  a  gelatinous  mass  being  obtained  which 
is  readily  soluble  in  water,  giving  a  yellowish  and  very  viscous  solution. 
In  practice  there  are  employed  one  molecule  of  cellulose,  two  molecules 
of  caustic  soda,  one  molecule  of  carbon  disulfide,  and  thirty  to  forty 
molecules  of  water.  The  corresponding  molecular  weights  of  these 
ingredients  are  as  follows : 

1  cellulose,  CbHioOs 165 

2  caustic  soda,  2NaOH 80 

1  carbon  disulfide,  CS2 76 

30-40  water,  30-40  H.O 540-720 


Viscose  is  an  alkaline  xanthate  of  cellulose,  and  its  industrial  manu- 
facture is  carried  out  in  the  following  general  manner:    Sheets  of  pure 

bleached  sulfite 
wood-pulp  are 
ground  up  with  solid 
caustic  soda  in  a  cir- 
cular edge-roller  mill 
until  a  finely  divided 
crumb-like  mass  is 
obtained.  The  pro- 
duct in  this  form  is 
known  as  "  crumbs," 
and  consists  of  alkali- 
cellulose.  This  oi> 
eration  should  be  so 
conducted  as  to  leave 
for  300  parts  of  alka- 
li-cellulose, 100  parts 
of  cellulose,  and  200 
parts  of  caustic  soda 
of  26°  Be.  That  is 
to  say,  the  pro- 
portion should  be 
about  100  parts  of 
dry  cellulose  to  48.5  parts  of  caustic  soda  (NaOH).  The  caustic  soda 
should  be  pure  and  free  from  carbonate  in  order  to  obtain  good  results. 

1  Steam,  Brit.  Pat.  1020  of  1898. 


Fig.  274.— Viscose  Silk.     (X350.)     (Micrograph  by  author.) 


VISCOSE  SILK  697 

The  excess  of  moisture  is  then  pressed  out,  and  the  material  is  allowed  to 
lie  for  some  time. 

The  alkali-cellulose  is  then  placed  in  an  iron  vat  provided  with  a  rotary 
stirrer,  where  it  is  treated  with  carbon  disulfide.  For  each  100  parts  of 
cellulose  there  should  be  used  34.5  parts  of  carbon  disulfide.  The  resulting 
mass  is  translucent  and  gelatinous  in  appearance  and  of  a  clear  brown  color 
and  is  known  by  the  name  of  viscose.  The  viscose  prepared  from  cotton 
is  of  a  brownish  color,  while  that  prepared  from  wood-pulp  is  more  of  an 
orange  color. 

Immediately  after  its  formation,  the  viscose  is  dissolved  in  water  and 
then  filtered  in  order  to  remove  any  cellulose  fiber  which  may  not  have 
undergone  chemical 
transformation.  For 
the  successful  prep- 
aration of  artificial 
silk  it  is  necessary 
that  the  filtering 
should  be  as  perfect 
as  possible,  for  the 
occurrence  of  any 
fibers  in  the  solution 
will  cause  stoppages 
of  the  spinnerets  and 
consequently  breaks 
in  the  filaments. 
After  filtering  the 
viscose  solution  is 
thoroughly  mixed. 
The  freshly  prepared 
solutions   of  viscose 

are   very   thick  and  Fig.  275.— Cross-sections  of  Viscose  Silk.    (X350.)     (Micro- 
viscous,  but  when  al-  graph  by  author.) 
lowed  to  "  ripen  "  for 

some  time  they  become  more  fluid  and  homogeneous.  Viscose  solutions 
are  tested  for  degree  of  ripening  by  treatment  with  a  40  percent  solution 
of  acetic  acid.  If  the  viscose  is  not  sufficiently  matured  it  will  dissolve, 
but  if  the  solution  has  arrived  at  its  proper  condition  the  viscose  will 
gradually  coagulate  and  give  a  solid  and  coherent  filament. 

When  the  desired  degree  of  fluidity  has  been  attained  (which  is  indi- 
cated by  means  of  a  viscosimeter^ ,  the  viscose  solution  is  run  into  suitable 
reservoirs,  in  which  it  is  maintained  at  a  temperature  of  32°  F.  Previous 
to  passing  into  the  spinning-machines,  the  solution  is  filtered  a  second  time, 
after  which  it  is  run  in^o  an  apparatus  where  it  is  subjected  to  high  pressure 


698  ARTIFICIAL  SILKS 

for  the  purpose  of  forcing  out  all  air-bubbles  which  are  liable  to  be  retained 
due  to  the  viscous  nature  of  the  solution.  This  latter  treatment  is  very 
essential,  as  the  presence  of  air-bubbles  would  intcrfer  every  materially 
with  the  regularity  of  the  spun  fiber. 

The  viscose  solution  then  goes  into  an  apparatus  which  may  be  called 
a  spinning-frame.  This  consists  of  a  double  series  of  small  pumps,  which 
force  the  solution  through  platinum  spinnerets  pierced  with  very  fine 
openings,  the  number  of  which  varies  with  the  size  of  the  thread  it  is 
desired  to  produce.  The  production,  therefore,  is  proportional  to  the  num- 
ber of  orifices  in  use;  the  normal  number  being  about  eighteen  orifices 
per  thread,  while  each  orifice  corresponds  to  a  daily  production  of  about 
28  grams  (alDOut  1  oz.).  Each  spinneret  and  tube  which  carries  it  are 
immersed  in  a  concentrated  solution  of  ammonium  sulfate,  or  dilute 
sulfuric  acid,  for  the  purpose  of  coagulating  the  liquid  jet  coming  from 
the  spinneret  by  l^ringing  it  into  immediate  contact  with  the  solution. 
The  different  filaments  forming  the  tlireads  are  at  the  same  time  united 
into  one  single  fiber,  and  these  are  carried  into  a  solution  of  ferrous  sulfate 
(copperas)  in  order  to  remove  all  residual  matter  left  on  the  fiber  from  the 
first  bath.  The  threads  then  pass  into  a  turbine  bobbin,  which  collects 
them  into  skeins,  and  at  the  same  time  gives  the  thread  the  desired  degree 
of  twist.  The  fiber,  in  the  form  of  hanks,  is  then  steeped  in  an  acid 
solution  for  the  purpose  of  neutralising  any  alkali  left  in  the  filaments, 
the  excess  of  acid  being  afterward  removed  by  washing  in  water.  Residual 
sulfur  compounds  are  removed  by  treatment  with  a  solution  of  sodium 
sulfide.  Sodium  bisulfate  as  well  as  sodium  bisulfite  with  aluminium 
sulfate  are  also  used.  The  fiber  at  this  stage  has  a  rather  pronounced 
yellow  color,  which  is  removed  by  bleaching  with  chloride  of  lime  or  better 
with  a  neutral  solution  of  sodium  hypochlorite.  Viscose  silk  has  a  fine 
glossy  appearance,  and  possesses  a  tensile  strength  about  equal  to  that  of 
pyroxylin  silk;  like  the  latter,  however,  it  is  also  weakened  when  moistened 
with  water. 

According  to  C.  F.  Cross,  the  experimental  plant  for  the  manufacture 
of  viscose  silk,  designed  and  erected  at  Kew  by  Stearn  and  Topham,  and 
its  rapid  improvement  to  the  stage  of  actual  production  of  a  merchantable 
'*  silk,"  was  a  marvelous  example  of  technical  insight  and  grasp  of  prin- 
ciple, for  it  comprised  the  use  of  the  pump  for  controlling  the  viscose 
delivery  for  the  unit  multiple  thread,  metallic  spinning  nozzles  with 
multiple  perforations  of  minute  diameter,  and  the  centrifuge-box  for 
collecting  and  laying  the  thread  and  imparting  the  required  twist,  which 
are  employed  to  this  day  in  producing  what  is  probably  the  larger  portion 
of  artificial  silk.  These  have  been  modified  in  detail  by  many  workers, 
particularly  by  Clayton,  and  the  number  of  variations  patented  is  now 
considerable.     The  principle  of  parallel  spinning  directly  on  bobbins  and 


VISCOSE  SILK  699 

twisting  afterwards,  which  was  developed  at  an  early  date  in  the  viscose 
factories  of  Germany  and  Italy,  has  survived,  and  is  turning  out  the 
"  silk  "  in  large  quantities,  but  experts  cannot  agree  as  to  the  relative 
merits  of  these  two  processes.  The  very  desirable  method  of  rotating 
the  spinning  jet  itself,  so  as  to  twist  the  thread  before  winding  it  on  to 
a  bobbin,  has  attracted  much  inventive  ingenuity,  but  the  considerable 
difficulties  which  arise  in  practice  are  still  to  be  overcome. 

With  regard  to  secondary  details,  an  enormous  number  of  variations 
have  been  proposed,  but  most  of  these  show  more  ingenuity  than  knowl- 
edge of  the  practical  problems  of  artificial  silk  manufacture.  On  the 
chemical  side,  almost  every  possible  and  many  quite  impossible  sub- 
stances have  been  proposed  as  additions  to  the  viscose  and  to  the  spinning 
bath.  Substances  have  been  added  to  the  viscose  with  the  purpose  of 
modifying  the  cellulose  to  a  thread  of  greater  softness  and  resistance 
to  water,  also  for  reducing  the  rate  of  ripening  of  the  viscose  so  as  to 
obtain  a  more  stable  product.  For  these  and  other  purposes,  the  addition 
of  the  following  have  been  proposed:  Sodium  silicate,  sodium  aluminatc, 
soap,  sodium  thiosulfate,  glycerol,  glucose,  urea,  salts  of  resinic  acid, 
phenol-formaldehyde  condensation  products,  albumen,  turpentine,  and 
naphthenic  acids. 

According  to  Bronnert,  the  cross-section  of  viscose  silk  threads  pro- 
duced in  an  acid  charged  with  an  excess  of  neutral  salt  exhibit  the  form 
more  or  less  of  a  star  or  a  ribbon  with  serrated  contours.  The  more  salt 
is  present  the  more  the  ribbon-like  form  prevails,  the  reason  being  a 
slower  coagulation  and  the  effect  of  the  winding-on  rollers  or  the  tension 
when  spinning  into  centrifugal  boxes.  This  silk,  however,  has  very  good 
covering  power,  and  is  preferred  for  weaving  purposes.  Viscose  silk  spun 
in  sulfuric  acid  alone  has  a  more  or  less  regular  round  contour;  the  same 
is  true  when  bisulfites  are  used  in  the  spinning  bath.  Threads  spun  in 
neutral  or  slightly  acidulated  ammonium  salts  also  have  a  perfectly  round 
contour. 

The  chemist  has  a  greater  latitude  with  regard  to  the  possible  com- 
ponents of  the  spinning  bath  and  this  has  resulted  in  the  following  list 
of  substances  proposed  for  this  purpose:  Sulfuric,  hydrochloric,  formic, 
acetic,  lactic,  citric,  tartaric,  glycollic,  and  aromatic  sulfonic  acids;  sul- 
fates of  ammonium,  sodium,  magnesium,  iron  and  zinc;  chlorides  of 
sodium  and  ammonium;  sodium  sulfite,  bisulfite,  and  thiosulf ates ;  alco- 
hols, starch,  sugars,  molasses,  aniline,  glycerol,  aldehydes,  ketones,  and 
lignone-sulfonic  lyes. 

The  principal  development  in  this  respect,  which  was  foreshadowed 
by  Stearn  and  Woodley  ^  for  spinning  a  purified  viscose,  has  been  the  use 
of  acid  solutions  for  spinning  so  as  to  get  a  cellulose  thread  directly  instead 

1  Brit.  Pat.  2529  of  1902. 


700  ARTIFICIAL  SILKS 

of  a  cellulose  xanthate  thread  which  has  to  be  subjected  to  further  treat- 
ment to  regenerate  the  cellulose.  Since  then,  the  value  of  both  salts 
and  acids  has  been  fully  appreciated,  and  various  mixtures  of  these  two 
classes  of  substances  have  held  the  field,  the  use  of  organic  substances 
such  as  glucose  having  proved  valuable  on  account  of  their  effect  in  modi- 
fying and  softening  the  action  of  the  acid  constituent. 

So  far,  viscose,  in  spite  of  its  undoubted  merits  has  not  shown  the  facility 
possessed  by  cuprammonium  solutions  of  being  spun  into  very  fine  fila- 
ments, as  is  being  done  by  Bemberg  and  Holken.  One  looks  forward  with 
interest  to  the  working  of  recent  patents  of  E.  Bronnert  in  this  connection, 
which  claim  to  produce  the  thread  in  a  range  of  5-2  deniers  and  to  extend 
the  industry  in  the  direction  of  substituting  silk.  The  usual  size  of  the 
viscose  silk  filaments  has  always  been  about  7  to  8  deniers  and  until 
recently  it  was  not  possible  to  produce  filaments  under  6  deniers  on  a 
commercial  scale.  Bronnert,  however,  has  shown  that  fiber  counts  down 
to  0.75  denier  can  be  made  by  the  use  of  fine  apertures  and  spinning 
into  a  bath  containing  a  higher  concentration  of  acid.  It  is  necessary 
that  this  latter  factor  be  accurately  adjusted  to  meet  the  conditions  for 
each  count.  Brilliancy  in  the  fine  counts,  may  be  varied  at  will,  and  with- 
out any  damage  to  the  strength  of  them.  To  reduce  brilliancy  and  to 
obtain  an  opaque  thread  it  is  only  necessary  to  lower  the  temperature. 
By  raising  the  temperature  a  thread  of  more  and  more  luster  is  produced. 
This  new  viscose  has  a  very  soft  touch,  with  an  increased  covering  power, 
dyes  evenly  and,  it  is  claimed,  when  woven  does  not  easily  crease. 

The  amount  of  free  alkali  and  comljined  alkali  present  in  viscose  may 
be  determined  quantitatively  through  the  difference  in  the  action  of  organic 
and  mineral  acids  on  viscose.  It  is  possible  to  treat  a  solution  of  viscose 
(cellulose  xanthate)  with  an  excess  of  acetic  acid  in  order  to  neutralise 
the  free  alkali  without  attacking  the  alkali  combined  with  the  cellulose 
group.  If  the  viscose,  however,  is  treated  with  dilute  sulfuric  acid  and 
boiled,  the  xanthate  is  decomposed,  and  thus  the  total  alkali  may  be 
obtained.     The  difference  in  the  two  results  gives  the  combined  alkali. 

The  analysis  is  carried  out  as  follows:  50  grams  of  the  viscose  are 
dissolved  in  water  and  made  up  to  a  volume  of  500  cc.  To  100  cc.  of  this 
solution  is  added  a  definite  volume  of  semi-normal  acetic  acid  in  sufficient 
excess  to  cause  total  precipitation  of  the  viscose.  The  precipitate  is 
filtered  off  and  washed  with  saturated  brine.  In  the  filtrate  so  obtained 
the  excess  of  acetic  acid  is  determined  by  titration  with  semi-normal 
caustic  soda,  using  phenolphthalein  as  indicator.  To  a  second  100  cc. 
sample  of  the  viscose  solution  is  added  50  cc.  (or  more  if  necessary)  of 
normal  sulfuric  acid.  The  solution  is  brought  to  boiling,  the  precipitate 
is  filtered  off  and  washed.  In  the  filtrate  the  excess  of  sulfuric  acid  is 
titrated  with  normal  caustic  soda  using  methyl  orange  as  indicator.     The 


VISCOSE  SILK  701 

acid  neutralised  by  the  viscose  gives  the  total  alkali,  and  the  difference 
between  the  first  result  and  this  latter  gives  the  alkali  combined  as 
xanthate. 

The  amount  of  sulfur  in  viscose  is  determined  by  first  oxidising  to 
sulfate  by  treatment  with  an  excess  of  sodium  hypochlorite,  then  pre- 
cipitating and  determining  by  the  usual  gravimetric  method  as  barium 
sulfate. 

The  determination  of  the  viscosity  of  viscose  solutions  is  an  important 
analytical  factor.  This  test  may  be  made  by  one  of  several  methods: 
(a)  The  solution  of  viscose  is  placed  in  a  30  cc.  Mohr's  burette  graduated 
in  1/10  cc,  and  having  an  orifice  1  mm.  in  diameter.  The  time  required 
for  30  cc.  of  the  solution  to  run  from  the  burette  is  noted.  If  this  time  is 
the  same  for  different  samples  from  the  solution  it  indicates  the  viscose 
is  well-ripened  and  homogeneous.  (6)  Another  method  is  to  employ  a 
glass  tube  3  cm.  in  diameter  with  two  marks  50  cm.  apart.  The  tube 
is  filled  with  the  viscose  solution  to  the  upper  mark  and  placed  in  a  verti- 
cal position.  A  small  nickel  ball  5  mm.  in  diameter  is  then  introduced, 
and  the  time  required  for  it  to  fall  between  the  two  divisions  is  noted.  A 
solution  in  proper  condition  for  spinning,  when  at  a  temperature  of  70°  F., 
should  show  sixteen  to  seventeen  seconds  for  the  fall  of  the  nickel  ball. 

(c)  Boverton  Redwood's  or  Engler's  viscosimeter  may  be  used.  In  these 
a  definite  volume  of  the  solution  to  be  tested  is  allowed  to  flow  through 
a  small  opening  and  the  time  compared  with  that  required  for  water. 

(d)  In  Doolittle's  apparatus  the  viscosity  is  determined  by  the  friction 
against  a  rotating  weight  moving  in  the  liquid,  the  motion  being  imparted 
to  the  weight  by  the  torsional  twist  of  the  suspending  wire. 

As  employed  for  purposes  of  spinning,  the  viscose  solution  should 
contain  about  6  to  7  percent  of  cellulose  and  8  percent  of  caustic  soda. 
In  ripening  or  aging  the  viscose  solution  a  temperature  of  about  70°  F.  is 
maintained  until  the  liquid  acquires  the  proper  fluidity.  The  ripening 
process  must  then  be  stopped  at  the  proper  point  by  cooling  the  solution 
to  23°  F.  by  refrigeration. 

In  the  spinning  of  viscose  silk  the  character  of  the  coagulating  bath 
has  much  to  do  with  the  contour  of  the  fiber  section.  In  the  Courtauld 
process  for  making  the  usual  threads  of  8  deniers,  a  bath  containing  only 
about  8  percent  of  sulfuric  acid  together  with  sulfate  and  glucose  is  used; 
the  section  of  this  fiber  is  irregular  in  outline  and  not  rounded  or  oval. 
The  weak  acid  bath  is  only  suitable  when  spinning  into  centrifugal  boxes 
where  the  individual  filaments  are  twisted  together  at  once,  as  in  the 
Courtauld  method.  In  the  Bronnert  process  the  bath  contains  16  to  18 
percent  of  sulfuric  acid  together  with  an  excess  of  sulfate,  and  the  spool- 
spinning  method  is  used.  This  system  is  particularly  of  use  where  silk 
of  lower  deniers  (from  60  to  120)  has  to  be  produced. 


702 


ARTIFICIAL  SILKS 


A  viscose  solution  will  begin  to  coagulate  seven  to  eight  days  after  its 
preparation.  The  coagulum  will  at  first  occupy  the  entire  volume  of  the 
solution,  but  soon  contracts  little  by  little.  After  forty-seven  days  the 
shrunken  coagulum  of  cellulose  hydrate  occupies  only  30  percent  of  the 
original  volume.  It  then  forms  a  rather  hard  mass,  and  is  known  as 
viscolith. 

When  viscose  silk  is  treated  with  formaldehyde  in  the  presence  of  acids 
and  dehydrating  agents  it  is  said  that  the  thread  acquires  a  greater  resist- 
ance to  moisture,  and  consequently  shows  less  loss  of  tensile  strength 
when  wetted.i  The  artificial  silk  is  placed  in  a  bath  containing  1-10  parts 
of  formaldehyde  and  90-99  parts  of  acetic  acid  (40  percent).  This  process 
is  known  as  "  sthenosage  "  or  strengthening. 

Cross  and  Bevan  -  give  the  following  table  showing  the  effect  of  the 
sthenosage  process  on  the  quality  of  artificial  silk: 


Artificial  silk  of  collodion,  cuprammonium  and 

viscose  methods 

Sthenose  products 


Breaking  Strain, 

Grams  per  Unit 

Denier. 


Air-dry . 


1.25 
1.6 


Wetted. 


0.37 
1.1 


Elasticity, 
Percent. 


Air-dry . 


12.2 

7.8 


Wetted. 


9.0 
7.6 


The  necessity  of  "  aging  "  or  "  ripening  "  viscose  solutions  previous  to 
spinning  has  been  obviated  by  the  addition  of  a  neutral  salt^  (such  as 

1  Eschalier,  Fr.  Pat.  374,724. 

^Jour.  Soc.  Chem.  Ind.,  1908,  p.  1189. 

3  Ernst  {U.  S.  Pat.  863,793  of  1907).  It  is  here  pointed  out  that  if  the  viscose 
formed  by  dissolving  the  cellulose  xanthate  in  a  suitable  solvent  be  allowed  to  stand 
or  "age"  for  a  sufficient  length  of  time,  it  will  of  itself  change  or  coagulate;  hence  it 
will  be  apparent  that  the  function  of  the  "aging"  process  is  to  allow  the  viscose  to 
approach  but  not  quite  reach  that  critical  point  at  which  it  of  itself  coagulates,  so 
that  all  that  is  needed  to  transform  it  into  a  filament  is  to  spin  it  into  a  weak  neutralising 
bath.  On  account  of  the  fact,  however,  that  it  is  impossible  to  obtain  absolutely 
uniform  cellulose  xanthate,  the  result  is  that  during  the  "aging"  process  certain 
portions  of  the  viscose  will  age  too  much,  and  particles  will  frequently  coagulate  which 
greatly  interferes  with  the  spinning  operations,  by  clodding  the  spinneret  tubes  and 
therefore  depreciating  the  quality  of  the  filaments  produced.  The  object  is,  first,  to 
produce  a  viscose  which  does  not  require  to  be  aged  but  nevertheless  will  coagulate 
immediately  when  the  filament  is  brought  into  a  weak  acid  bath,  although  the  viscose 
be  fresh,  and  to  preserve  the  viscose,  and  second,  to  so  check  the  action  of  the  carbon 
bisulfide  as  to  enable  the  viscose  to  be  stored  until  needed  for  spinning.  Freshly 
formed  viscose  ordinarily  would  be  coagulated  by  ejecting  it  through  a  spinneret  into 
a  strong  acid  bath,  but  the  filament  produced  could  not  be  formed  commercially  as 


VISCOSE  SILK 


703 


sodium  sulfite  or  sodium  silicate)  to  the  solvent  for  the  cellulose  xanthate 
before  the  latter  is  added.  This  imparts  to  the  viscose  solution  the 
property  of  immediately  coagulating  when  ejected  into  a  weak  acid  bath. 

By  coating  a  cotton  thread  with  a  solution  of  viscose  an  imitation 
horsehair  can  be  obtained.  This  product  is  known  under  the  name  of 
"  visceUine  "  yarn. 

According  to  Foltzer  {Textile  Manufacturer),  the  raw  material  for 
the  manufacture  of  viscose  is  wood-pulp  freed  from  grease  and  bleached, 
similar  to  that  which  is  used  in  the  manufacture  of  paper.  It  is  used  in 
preference  to  cotton,  because  it  is  cheaper.  Although  this  pulp  is  often 
delivered  ready  for  use  at  the  artificial- 
silk  factory,  it  is  always  a  wise  plan  first 
to  wash  it  well  with  a  large  quantity  of 
water.  In  general  this  wood-pulp  is  not 
sufficiently  free  from  grease;  in  this  state 
it  cannot  be  satisfactorily  employed  for 
the  viscose  process,  and  should  be  sub- 
mitted to  a  process  somewhat  similar 
to  the  following:  In  a  boiling  kier  of  a 
similar  type  to  that  which  is  used  in  the 
preparation  of  cotton  the  wood-pulp  is 
subjected  to  boiling  for  about  three  and 
one-half  hours  in  a  bath  of  soda  of  1^° 
to  2°  Be.  Ferruginous  or  calcareous 
water  must  on  no  account  be  used  in 
this  process.  After  the  pulp  has  been 
boiled,  the  soda  lye  is  allowed  to  flow 
out,  the  substance  is  well  rinsed  with  y///////////////////// 
water,  preferably  at  a  temperature  of  ^xg.  276.— Mixing  Tank  for  Viscose. 
25°  to  30°  C,  and   finally  it  is  placed  (Foltzer.) 

in    a    hydroextractor.       The  wood-pulp 

thus  treated  is  transformed  into  alkali-cellulose  in  the  following  manner: 
After  the  processes  of  washing  and  hydroextracting,  the  pulp  contains 
from  40  to  50  percent  of  water,  and  it  is  essential  that  this  percentage 
should  be  determined  accurately.  For  this  purpose  a  sample  of  the 
partly  dried  pulp  is  heated  at  a  temperature  of  103°  to  105°  C.  until  there 
is  no  further  diminution  in  weight.  The  difference  in  the  weights  of  the 
partly  dried  and  perfectly  dried  pulp  clearly  gives  the  amount  of  water, 
and  with  tables,  such  as  are  used  in  the  conditioning  of  yarns  and  fibers, 

by  this  process  it  would  be  very  weak  and  possess  little  or  no  elasticity.  To  produce 
a  strong  elastic  thread  the  viscose  must  be  ejected  into  a  weak  acid  bath;  hence  it  is 
necessary  to  employ  a  viscose  solution  which  will  coagulate  immediately  into  a  filament 
wlicn  ejected  into  the  weak  acid  bath. 


^?^r:^^^I^mm77777777777777P7m7P7, 


704 


ARTIFICIAL  SILKS 


the  percentage  of  moisture  can  be  obtained.  According  to  the  researches 
of  Beltzer,  200  grams  of  caustic  soda  at  26°  Be.  are  required  to  transform 
100  grams  of  celhilose  (in  this  case  wood-pulp)  into  300  grams  of  alkah 
cellulose;  but  the  percentage  of  moisture  in  the  partly  dried  pulp  must 
be  taken  into  account  in  order  to  arrive  at  the  exact  amount  of  caustic 

soda  required.  The  duration  of 
the  action  of  the  caustic  soda  on 
the  pulp  must  be  extended  in  the 
manufactm'e  until  a  uniform  alkali- 
cellulose  is  obtained,  and  to  achieve 
this  end  it  is  necessary  from  time  to 
time  to  make  trials  to  determine 
when  the  impregnation  is  complete. 
This  operation  demands  much 
care  and  attention  when  the  manu- 
facture is  carried  out  on  a  large 
scale,  and  it  is  necessary  to  choose 
mixing  tanks  in  which  the  work 
may  be  quickly  performed,  and  in 
which  all  the  cellulose  will  be  im- 
pregnated uniformly  in  a  relatively 
short  time — about  three  and  one- 
quarter  hours.  The  mixing-tanks 
described  and  illustrated  for  the 
manufacture  of  artificial  silk  by 
the  cuprammonium  process  are 
not  suitable  for  the  viscose  indus- 
try; it  is  advisable  for  this  pro- 
cess to  use  mixing-tanks  somewhat 
similar  to  that  illustrated  in  Fig. 
276.  The  wood-pulp  is  introduced 
into  the  cylinder  (A) ;  the  apparatus 
is  then  put  into  motion  and  at  the 
same  time  the  soda  liquid  is  allowed 
to  enter  by  pipe  (B).  The  alkali- 
cellulose  obtained  by  this  process 
is  in  the  form  of  a  bleached 
pulp,  which  is  removed  from  the  mixing-tank  at  the  opening  (C)  (where 
the  hinged  door  is  shown  in  the  dotted  position),  into  the  wagon  (D), 
in  which  it  is  carted  to  the  apparatus  illustrated  in  Fig.  277,  where  it  is 
transformed  into  viscose.  The  interior  case  of  the  jacketed  cylinder  is 
lined  with  nickel.  The  alkali-cellulose  previously  prepared  for  transforma- 
tion into  viscose  paste  is  introduced  by  the  opening  (B).     The  lid  (B)  is 


Fig.  277. — Apparatus  for  Preparing  Viscose. 
(Foltzer.) 


VISCOSE  SILK  705 

hermeticalh^  sealed ;  the  agitators  are  then  set  in  motion,  and  are  kept 
rotating  for  twenty  to  thu'ty  minutes.  Carbon  disulfide  flows  through 
the  pipe  (D),  and  the  necessary  quantity  is  admitted  into  tank  (A)  by 
opening  the  valve  (E).  For  the  transformation  of  200  kilos,  of  alkali- 
cellulose,  34  kilos,  of  carbon  disulfide  are  required.  The  ingredients  must 
then  be  mixed  for  three  to  four  hours  in  order  to  obtain  a  homogeneous 
substance  which  has  a  dark  yellowish  orange  color.  After  the  process 
of  mixing  has  been  in  operation  for  the  time  indicated,  200  kilos,  of  caustic 
soda,  made  up  into  a  15  percent  solution,  are  added  to  the  mixture,  and 
the  mixing  is  continued  until  a  uniform  pulp  is  obtained;  the  caustic 
soda  comes  from  a  graduated  reservoir  through  pipe  (F).  The  viscose 
thus  obtained  is  then  deposited  into  the  mixing-tank  (H),  mounted  on  a 
wagon.  The  viscose  is  then  diluted  with  water  in  mixing-tank  (H),  in 
the  proportion  of  185  liters  of  water  to  100  kilos,  of  viscose  pulp.  It  is 
desirable  during  all  these  operations  that  the  temperature  should  not 
exceed  25°  C,  and  when  these  operations  are  completed  that  the  mixing- 
tank  (A)  should  be  cooled  by  allowing  a  freezing  mixtm-e  to  flow  through 
the  jacketed  part  (J).  The  solution  is  then  mixed  for  four  hours  in  the 
apparatus  (H),  and  finally  aUowed  to  stand  for  ten  to  fourteen  hours; 
during  this  time  liquefaction  proceeds  gradually,  and  it  must  be  arrested 
when  the  consistency  of  the  substance  is  most  favorable  for  transformation 
into  threads;  this  point  is  determined  by  means  of  a  viscodmeter.  If  this 
point  is  passed,  liquefaction  continues,  followed  some  time  after  by  decom- 
position, with  later  a  solid  deposit  of  cellulose.  Before  the  solution  is 
spun — an  operation  which  is  performed  under  a  pressure  of  3  to  4  atmos- 
pheres— it  is  filtered  and  the  air  cells  are  removed  from  it  by  an  aspirator. 
7.  Acetate  Silk. — The  acetate  of  cellulose  has  also  been  used  as  a  basis 
for  the  manufacture  of  artificial  silk.^  It  is  dissolved  in  a  suitable  solvent  ^ 
and  spun  in  the  same  manner  as  collodion  silk,  the  thread  being  coagulated 
by  passing  through  a  bath  of  water.  With  coUodion  silk  the  weight  of 
the  product  obtained  (after  denitration)  is  scarcely  equal  to  that  of  the 
ceUulose  used,  whereas  with  acetyl  cellulose  the  weight  of  the  resulting 
silk  corresponds  to  about  twice  the  weight  of  the  ceUulose  taken.  The 
silk  made  from  acetyl  cellulose,  however,  is  less  stable  toward  acids  and 
alkalies  than  collodion  silk,  neither  does  it  dye  as  readily;  and  the  dj'eing 
is  best  done  by  adding  the  coloring  matter  to  the  solution  before  spinning. 
The  silk  made  from  acetyl  cellulose  is  known  as  "ceUestron,"  "  celanese,"  or 
"  acetate  "  silk,  and  is  used  for  covering  electric  wires,  as  it  has  remarkable 
insulating  properties. 

1  Acetate  silk  has  been  made  experimentally  by  the  Henckel  Domiersmarck  works 
at  Stettin,  and  is  now  made  on  a  fair-sized  commercial  scale  by  the  British  Cellulose 
Products  Co.     The  production  of  acetate  sUk  is  also  being  attempted  in  America. 

2  Chloroform,  ethyl  acetate  and  alcohol,  or  acetic  acid  may  be  employed  as  solvents 
for  cellulose  acetate. 


706  ARTIFICIAL  SILKS 

The  chief  advantage  claimed  for  acetate  silk  over  other  forms  of  arti- 
ficial silk  is  that  it  is  not  so  much  affected  by  either  hot  or  cold  water. ^ 
The  acetate  silk,  however,  that  has  appeared  commercially  in  trade  does 
not  seem  to  have  much  greater  strength  either  dry  or  wet  than  the  other 
forms  of  cellulose  silk.- 

Cellulose  acetate  solutions  may  also  be  employed  for  coating  cotton 
threads  to  produce  an  artificial  horsehair  impervious  to  water.^ 

The  single  filaments  of  acetate  silk  under  the  microscope  appear  as 
uniform  cylinders  with  occasional  band-like  thickenings.  The  cross- 
section  is  oval  to  cu-cular,  and  the  average  diameter  is  42.3  microns. 
The  strength  of  a  thread  of  18  single  filaments  was  found  to  be  226  grams 
when  dry  and  128  grams  when  wetted.  Acetate  silk  is  soluble  in  cold 
acetic  acid,  but  insoluble  in  ammoniacal  copper  hydroxide.  Iodine  and 
sulfuric  acid  gives  a  yellow  color,  as  does  also  zinc  chlor-iodide.  It  burns 
quickly  with  a  disagreeable  odor  and  leaves  a  massive  charcoal  residue. 
It  is  distinguished  from  all  other  artificial  silks  by  its  low  density  (1.25) 
and  by  not  swelling  in  water.'* 

The  production  of  soluble  compounds  of  cellulose  acetate  by  the  action 

1  Cellulose  acetate  does  not  swell  in  pure  water  or  absolute  alcohol,  but  swells 
greatly  in  mixtures  of  water  with  alcohol  or  other  organic  liquids.  Two  methods  are 
described  by  which  the  degree  of  swelling  of  the  colloid  was  measured.  "Unswollen" 
cellulose  acetate  is  colored  only  very  slowly  in  an  aqueous  dye  bath  at  25°  C;  with 
shghtly  swollen  cellulose  acetate  the  maximum  color  is  reached  in  several  months,  and 
with  fully  swollen  cellulose  acetate  the  hmiting  value  of  the  color  under  the  same 
conditions  is  attained  in  a  few  minutes.  Raising  the  temperature  hastens  these  color 
processes.  The  significance  of  the  relation  between  speed  of  coloration  and  degree 
of  swelUng  for  the  dyeing  of  textile  fibers  and  staining  in  microscope  work  is  shown. 
Unswollen  cellulose  acetate  is  very  difficultly  saponifiable,  but  swollen  cellulose  acetate 
is  completely  saponified  by  0.5N  potassium  hydroxide  in  a  few  hours  at  room  tem- 
perature, and  the  velocity  of  the  reaction  increases  with  the  degree  of  swelling.  A 
convenient  and  accurate  method  of  acetyl  determination  is  based  on  the  behavior  of 
swollen  cellulose  acetate  toward  dilute  aqueous  alkalies  at  room  temperature. 

2  In  the  development  of  cellulose  acetate  for  silk  it  was  hoped  to  take  advantage 
of  certain  facts  such  as  the  following:  (1)  it  is  of  notably  lower  specific  weight,  and 
approximates  that  of  natural  silk;  (2)  as  an  ester  derivative  it  should  have  a  resistance 
to  water  much  greater  than  even  normal  cellulose;  (3)  as  an  ester,  it  represents  a 
considerable  increase  of  weight  in  relation  to  the  raw  material,  whereas  all  other  forms 
of  cellulose  silk  represent  a  lower  weight;  (4)  the  thread  once  formed  is  in  its  saleable 
form,  requiring  only  the  mechanical  treatments  incidental  to  finish.  The  thread  of 
acetate  silk  is  produced  at  the  rate  of  100  meters  per  minute,  whereas  viscose  silk  can  be 
spun  only  at  a  rate  of  45  to  50  meters  per  minute;  therefore  a  greater  production 
per  spinneret  may  be  obtained  from  acetate  silk.  But  the  cellulose  acetate  fulfilling 
the  requirements  for  spinning  into  a  thread  has  colloidal  structural  characteristics 
inferior  to  the  nitric  acid  ester,  and  the  acetate  silk  fails  to  show  superiority  to  the 
other  cellulose  silks  in  tenacity  in  either  the  dry  or  wet  state. 

3  gee  Fr.  Pat.  369,123  of  1906  and  376,578  of  1907. 
*  Herzog,  Chem.  Zeil.,  1910,  p.  347. 


VISCOSE  SILK  707 

of  acetic  anhydride  and  glacial  acetic  acid  on  cotton,  always  requires  the 
presence  of  a  so-called  catal>i:ic  agent.  These  catalytic  agents  as  specified 
in  a  large  number  of  patents  may  be  grouped  in  three  classes :  free  mineral 
acids,  weaker  acids  and  acid  salts,  and  neutral  salts  which  are  readily 
dissociated.  Schwalbe  ^  discusses  the  mechanism  of  these  reactions  and 
points  out  that  the  production  of  the  cellulose  acetate  is  always  accom- 
panied by  a  more  or  less  profound  modification  of  the  cellulose,  as  evidenced 
by  the  copper  reducing  properties  of  the  cellulose  residue  after  the  saponi- 
fication of  the  acetate.  Of  the  mineral  acid  group  of  catalytic  agents, 
sulfuric  acid  is  by  far  the  most  important,  and  its  appHcation  is  amply 
illustrated  in  the  patents  of  Lederer  and  Bayer  &  Co.  The  principal 
representatives  of  the  second  group  are  the  phenolsulfonic  acid  of  Mork's 
patent,  and  the  halogenated  fatty  acids  of  Knoll  &  Co.  Schwalbe  attrib- 
utes the  catalji;ic  effect  of  these  bodies  to  the  presence  of  limited  quan- 
tities of  free  mineral  acid.  Representatives  of  the  third  group  include 
such  bodies  as  ferrous  sulfate,  ferric  chloride,  diethylamine  sulfate,  etc., 
found  chiefly  in  Knoll  &  Co.'s  patents.  These  so-called  neutral  salts 
possess  weak  bases  and  free  mineral  acids  are  produced  from  them  by 
dissociation. 

Cellulose  acetate  is  not  soluble  in  aqueous  liquids,  and  for  this  reason 
the  production  of  filaments  from  it  largely  follows  the  Chardonnet  proc- 
ess; also,  for  the  same  reason,  the  thread  produced  from  it  is  soluble  in 
or  softened  by  numerous  organic  solvents.  The  thread  is  stated  to  be 
impervious  to  water;  this,  however,  does  not  cause  its  strength  when  wet 
to  be  greater  than  that  of  viscose  silk,  and  in  the  dry  state  its  tenacity  is 
considerably  lower.  The  production  of  acetate  silk  is  apparently  still 
in  the  experimental  stage,  for  it  cannot  yet  be  obtained  for  commercial 
purposes  in  any  large  quantity,  although  small  quantities  have  been 
exhibited,  and  the  samples  which  are  obtainable  possess  properties  of 
which  most  users,  whether  textile  workers  or  dyers,  will  probably  need 
considerable  experience  before  they  will  be  persuaded  to  accept  them  as 
desirable  in  a  standard  yarn.  It  is,  for  instance,  unique  in  its  dyeing 
properties,  in  that  with  ordinary  methods  it  can  be  dyed  only  by  means 
of  basic  dyes,  which  are  among  the  most  fugitive  of  coloring  matters  ;2 
direct  cotton  colors  it  refuses  to  take  up,  and  the  dyeing  of  fabric  com- 
posed of  cotton  and  artificial  silk  with  direct  colors,  a  very  usual  procedure, 

1  Zeit.  angew.  Chetn.,  1910,  p.  435. 

^  According  to  Brit.  Pat.  158,340,  cellulose  acetate  silk  may  be  dyed  after  treat- 
ment with  a  solution  of  ammonium  thiocyanate.  This  treatment  increases  its  affinity 
for  all  classes  of  dyestuffs.  Fabrics  containing  cellulose  acetate  silk  are  immersed 
for  two  to  sixty  minutes  at  ordinary  temperature  in  a  5  to  25  percent  solution  of 
ammonium  suKocyanide,  thoroughly  washed,  and  dyed  in  the  usual  way.  The 
ammonium  thiocyanate  may,  in  some  cases,  be  added  to  the  dyebath.  Sodium, 
potassium,  and  calcium  thiocyanates  may  also  be  used. 


708  ARTIFICIAL  SILKS 

is  not  possible  in  the  case  of  acetate  silk.  If  this  is  attempted  with  acetate 
silk,  the  cotton  takes  up  the  color  normally,  but  the  acetate  combines  only 
with  the  basic  irnpurities  in  the  dye,  with  the  result  that  the  former  may 
be  the  desired  navy  blue  while  the  latter  is  perhaps  a  dirty  yellow  shade, 
or  while  the  former  is  black,  the  latter  is  brick-red.  When  dyeing  is 
attempted  with  vat  colors  of  the  indanthrene  type,  which  are  coming 
into  great  demand  on  account  of  their  remarkable  fastness  and  conse- 
quent suitability  for  washable  materials,  cellulose  acetate  silk  sometimes 
is  partly  decomposed,  and  loses  its  luster  and  silk-like  properties.  Con- 
siderable effort  has  been  made  to  devise  methods  for  the  satisfactory 
dyeing  of  acetate  silk  with  substantive,  and  it  has  been  found  that  a 
treatment  of  the  fiber  with  a  solution  of  caustic  soda  (saponification) 
previous  to  dyeing  gives  very  good  results  without  materially  affecting 
the  quality  of  the  silk.  It  is  understood  that  the  manufacturers  of  this 
silk  now  place  the  treated  material  on  the  market  ready  for  dyeing. 

Acetate  silk  has  a  very  low  electric  conductivity,  and  consequently 
may  prove  to  be  a  very  useful  material  for  the  covering  of  electric  wires 
and  for  other  insulating  purposes;  in  such  cases,  where  coloring  is  often 
desirable,  but  numerous  or  exact  shades  are  not  necessary,  the  methods 
and  dyestuffs  available  maj^  give  sufficiently  good  results.^ 

Another  use  to  which  cellulose  acetate  has  been  put  is  that  of  coating 
cotton  or  silk  threads  with  soluble  acetates  in  admixture  with  a  metal 
powder.  To  increase  the  pliability  of  the  thread,  certain  substances 
such  as  acetin  and  acetyl-benzyl-orthotoluidine  are  added. ^  The  product 
was  known  as  Bayko  yarn  and  gave  a  beautiful  imitation  of  gold  and  silver 
threads,  which,  however  could  be  toned  to  any  desired  shade  and  used  for 
ornamental  fabrics.  Another  use  of  cellulose  acetate  was  to  make  so-called 
"  solid  "  alcohol,  or  alcohol  tablets.  These  consist  of  10  percent  of  cellu- 
lose acetate  and  90  percent  of  alcohol,  and  have  proved  to  be  very  useful 
where  the  liquid  alcohol  cannot  be  conveniently  transported.  Another 
interesting  use  of  cellulose  acetate  is  in  the  product  known  as  Sericose  L. 
This  consists  of  the  tri-acetate  soluble  in  alcohol  and  acetic  acid  and  is 
employed  as  a  thickener  and  agglutinant  for  obtaining  various  printing 
effects,  especially  for  making  imitation  Swiss  polka  dot  fabric. 

Within  the  last  decade  acetate  of  cellulose  has  been  largely  used  in  the 
manufacture  of  films  and  for  waterproofing  fabrics.  There  may  be 
mentioned  among  others,  the  films  of  the  Boroid  Company,  London; 
Lumiere  and  Planchon,  of  Lyons;  la  Societe  "  Cellon,"  which  employs 
the  Eichengriin  patents;  and  la  Societe  "  Cellophane,"  at  Thaon-les- 
Vosges. 

8.  Gelatine  Silk. — This  is  a  thread  of  gelatine,  and  consequently 
differs  from  the  other  artificial  silks  in  that  it  consists  of  animal  tissue  and 

1  See  Jour.  Soc.  Chem.  Ind.,  1920,  p.  267.  ^  gee  Brit.  Pat.  11,354  of  1909. 


PROPERTIES  OF  ARTIFICIAL  SILK  709 

not  vegetable.  Due  to  this  circumstance,  it  has  more  analogy  chemically 
to  true  silk  than  the  various  cellulose  silks.  The  manufacture  of  this  fiber 
known  as  vanduara  silk  was  conducted  by  forcing  an  aqueous  solution 
of  gelatine  through  a  fine  capillary  tube;  the  thread  so  produced  is  carried 
on  an  endless  band  through  a  drying-chamber.  The  soft  gelatine  thread, 
of  course,  flattens  out  considerably  during  this  operation,  hence  the  silk 
eventually  forms  a  flat,  ribbonlike  fiber.  After  drying  and  properly  reehng 
the  fiber  is  treated  with  vapor  of  formaldehyde,  which  causes  the  gelatine 
to  become  insoluble  in  water.  By  varying  the  pressure  on  the  gelatine 
solution,  whereby  it  is  forced  through  the  capillary  tube,  the  thickness 
of  the  fiber  may  be  increased  or  diminished.  The  same  result  may  be 
attained  by  varying  the  speed  of  the  endless  band  which  carries  the  thread 
after  coming  from  the  capillary  tube.  The  silk  may  be  dyed  either  in  the 
ordinary  way  in  skein  form  after  reeling,  or  the  gelatine  solution  may  be 
colored  before  the  thread  is  drawn  out.  The  fiber  is  very  lustrous,  and  if 
the  filaments  are  drawn  fine  enough  the  silk  is  soft  and  pliable. 

Vanduara  silk  is  an  English  invention,  the  patentee  being  Adam  Millar .^ 
The  silk  has  never  appeared  on  the  market  as  a  commercial  commodity, 
and  the  process  does  not  seem  to  have  met  with  any  marked  degree  of 
success.  Another  process  giving  a  thread  of  a  similar  character  was  that 
of  Todtenhaupt.^     The  latter  uses  an  alkaline  solution  of  casein. 

Another  interesting  form  of  artificial  silk  is  that  known  as  Lowe  silk; 
it  consists  of  a  real  silk  cocoon  filament  smTOunded  by  a  solution  of  artificial 
silk  so  that  the  two  conglomerate  together  into  one  continuous  fiber. 
It  has  the  handle  and  luster  of  real  silk  and  also  dyes  well.  So  far  it  is 
only  in  the  experimental  stage  and  has  not  been  placed  on  the  market 
commercially. 

9.  Properties  of  Artificial  Silk. — The  chief  drawback  to  the  commercial 
success  of  artificial  silk  has  been  its  behavior  with  water.  When  wetted 
with  water  the  fiber  swells  up  to  a  considerable  extent,  pyroxylin  silk 
increasing  in  thickness  by  over  60  percent  in  an  hour  and  viscose  silk  by 
about  45  percent  in  ten  minutes.  Fibers  of  ordinary  silk  and  also  tussah 
silk  remain  practically  unaltered  when  wetted.  When  wetted  the  fiber 
of  artificial  silk  loses  its  original  strength  to  such  a  degree  that  it  must  be 
handled  with  great  care.  Soap  solutions  and  dilute  acids  have  no  injurious 
effect,  but  alkaline  solutions  rapidly  disintegrate  the  fiber  and  finally 
dissolve  it  completely.  Strehlenert  has  endeavored  to  prevent  the  loss  of 
strength  in  collodion  silk  when  wetted  by  the  addition  of  formaldehyde  to 
the  collodion  solution.^  This  process,  however,  does  not  appear  to  have 
been  a  success. 

1  Brit.  Pat.  15,522  of  1894. 

2  Brit.  Pat.  25,296  of  1904.  f 
»  Brit.  Pat.  22,540  of  1896. 


710  ARTIFICIAL  SILKS 

The  material  is  rather  difficult  to  dye,  on  account  of  the  weakening 
action  of  water,  and  the  operation  must  be  carried  out  with  great  care. 
The  dyeing  is  accomplished  without  the  addition  of  either  soap  or  acid  to  the 
bath.  The  basic  coloring  matters  and  some  of  the  direct  cotton  colors 
appear  to  be  the  best  dyestuffs  to  employ. 

Another  feature  in  which  artificial  silk  is  inferior  to  natural  silk  is  its 
lack  of  "  covering  power."  That  is  to  say,  the  filaments  of  true  silk  form 
a  more  open  thread  which  presents  a  thicker  appearance  than  a  thread  of 
artificial  silk  of  the  same  weight.  Consequently  a  fabric  woven  from  real 
silk  is  more  solid  in  appearance,  or  better  covered  than  a  corresponding 
fabric  made  of  artificial  silk  threads  of  the  same  size  and  weight. 

Most  of  the  artificial  silk  produced  at  the  present  time  is  spun  in 
about  150  denier  size,  corresponding  to  about  37's  cotton  yarn.  Silk  of 
120  denier  size  is  also  used.  The  number  of  individual  filaments  in  a 
thread  of  120  denier  ranges  from  16  to  25,  hence  the  size  of  the  individual 
fiber  is  about  5-8  denier,  in  comparison  with  real  silk  which  averages 
1.25  denier  to  each  filament.  Thiele's  silk  (cellulo)  has  been  made  as 
fine  as  30-50  denier  and  containing  45-60  filaments,  making  each  of  the 
latter  0.5-1.2  denier  in  size,  or  even  finer  than  the  filament  of  natural  silk. 
The  finer  the  denier,  the  greater  covering  power  of  the  silk,  but  also  the 
higher  its  cost.  There  is  very  little  demand  at  the  present  time  for  artificial 
silk  finer  than  120  denier. 

In  their  dyeing  properties  the  artificial  silks  are  in  general  similar  to 
cotton  or  other  cellulose  fibers.  Owing  to  the  fact  that  artificial  silk  loses 
about  60  percent  of  its  strength  when  wetted  great  care  must  be  used  in 
handling  the  yarn  when  dyeing,  washing,  or  bleaching.  According  to 
Jentsch  collodion  silk  differs  from  viscose  and  cuprate  silks  Id  taking  up 
basic  dyes  directly  without  the  aid  of  a  mordant;  this  is  probably  explained 
by  the  fact  that  collodion  silk  contains  oxycellulose.  The  substantive 
dyes,  however,  are  principally  used  in  the  dyeing  of  artificial  silk,  a  topping 
with  basic  dyes  often  being  given  in  order  to  brighten  the  color.  In  dyeing 
artificial  silk  the  temperature  of  the  bath  should  not  exceed  160°  F.  The 
principal  defect  in  the  dyeing  of  artificial  silks  is  tendency  toward  uneven 
colors.  This  defect  is  doubtless  inherent  in  the  structure  of  the  silk  itself, 
the  density  of  the  fiber  lacking  complete  homogeneity.  In  collodion  silk 
this  defect  has  been  attributed  to  differences  in  the  amount  of  residual 
nitrogen  in  the  fiber,  the  darker  shades  resulting  from  higher  percentages 
of  nitrogen.  Unevenness  in  colors  may  often  be  remedied  by  topping 
slightly  with  a  basic  dyestuff. 

The  differences  experienced  in  the  dyeing  of  different  forms  of  artificial 
silk  are  of  interest.  The  nitro  or  collodion  silks  have  a  strong  affinity 
for  basic  dyes  and  unless  care  is  used  the  colors  will  be  uneven.  The 
cuprate  silks  have  less  affinity  for  basic  dyes,  and  for  the  production 


PROPERTIES   OF  ARTIFICIAL  SILK  711 

of  full  shades  it  is  necessary  to  mordant  with  tannic  acid.  The  direct 
cotton  dyes  give  the  best  results;  sulfur  dyes  and  vat  dyes  may  also  be 
used  but  will  generally  injure  somewhat  the  luster.  Viscose  silk  is  similar 
to  mercerised  cotton  in  its  affinity  for  dyestuffs.  The  acetate  silk  as  at 
first  produced  could  not  be  dyed  satisfactorily  as  the  cellulose  acetate  was 
impervious  to  water,  but  the  acetate  silk  now  produced  is  partially  saponi- 
fied and  contains  hydroxjd  groups  which  give  the  silk  a  much  greater 
affinity  for  dyestuffs.  Cellulose  acetate  silk  has  but  little  affinity  for  the 
direct  cotton  dyes,  and  in  order  to  dye  with  these  colors  special  treatment 
must  be  resorted  to,  which  consists  of  working  the  silk  in  a  bath  of  caustic 
soda,  or  in  some  cases  the  caustic  soda  may  be  employed  directly  in  the 
bath  with  the  dyestuff.  This  treatment  does  not  seem  to  have  any 
effect  on  the  material  nor  to  effect  the  luster.  The  basic  dyes  have  a 
direct  affinity  for  acetate  silk  and  no  mordanting  is  necessary.  Many 
of  the  acid  dj^es  are  also  useful  for  acetate  silk.  The  new  series  of  dye- 
stuffs  discovered  by  Green  and  known  as  ''  lonamines  "  have  a  remarkable 
affinity  for  acetate  silk  and  may  be  dyed  directly  on  that  fiber. 

When  artificial  silks  are  woven  into  fabrics  with  cotton  or  wool,  or 
natural  silk,  or  with  a  combination  of  these  fibers,  or  when  the  artificial 
silks  are  to  remain  undj^ed  for  effect  purposes,  many  difficulties  are 
encoimtered  on  account  of  the  different  affinities  of  the  fibers  towards  the 
dj'estuffs.  Each  case  has  to  be  treated  individually,  and  it  is  principally 
a  matter  of  selecting  the  proper  d3'estuff  for  the  purpose  at  hand  and  then 
properly  regulating  the  temperature  of  the  dyebath.  To  decrease  the 
affinity  of  the  artificial  silks,  especially  the  cuprate  and  viscose  silks, 
toward  substantive  dyes,  when  interwoven  with  cotton,  a  process  has 
been  recommended  consisting  of  a  treatment  of  the  fabric  with  10  to  15 
percent  of  tannic  acid  for  a  few  hours  at  150°  F.,  and  afterward,  without 
rinsing,  treating  with  a  lukewarm  bath  containing  6  to  10  percent  of 
stannous  chloride  (on  the  weight  of  the  material).  The  stannous  chloride 
is  dissolved  with  the  addition  of  a  little  hydrochloric  acid. 

The  acid  rotting  of  artificial  silk  is  a  defect  to  be  met  with  in  that  silk 
prepared  by  Chardonnet's  method  from  nitrated  cellulose.  When  such 
artificial  silk  is  dyed  certain  irregularities  are  frequently  to  be  noticed, 
the  cause  of  which  has  hitherto  been  generally  attributed  to  atmospheric 
conditions  as  all  tests  for  the  presence  of  deleterious  substances  in  the 
materials  used  in  the  dyeing  process  have  failed  to  show  anj'thing  which 
might  be  considered  as  a  possibility  in  the  production  of  the  defects 
noticed.  These  irregularities  are  said  to  be  readily  corrected  bj^  immersing 
the  dj'ed  material  in  water  for  some  time  and  again  dyeing,  but  this 
occasions  inconvenience  and  considerable  loss  of  time.  Heermann  has 
shown  that  this  acid  rotting  is  due  to  the  presence  of  unstable  sulfmic 
acid  compounds  of  ^^Uulose  in  the  fiber,  and  as  these  irregularities  in  dyeing 


712 


ARTIFICIAL  SILKS 


are  only  to  be  met  with  in  the  case  of  artificial  silk  from  nitrated  cellulose 
and  not  in  the  silk  prepared  by  the  viscose  or  cuprammonium  processes, 
it  was  possible  that  they  were  due  to  this  acid  rotting  of  the  fiber.  This 
view  has  now  been  confirmed  by  the  fact  that  extracts  from  unsatisfactory 
dyeings  gave  a  much  greater  precipitate  through  a  solution  of  barium 
hydroxide  than  those  obtained  from  satisfactory  dyeings.  It  is  said 
that  the  results  of  acid  rotting  may  be  avoided  by  neutralising  the  fiber 
by  treatment  with  an  8  to  12  percent  solution  of  sodium  acetate  or  sodium 
formate  or  borax.  The  material  is  then  dried  without  washing.  Further- 
more, the  tendency  of  the  fiber  to  become  weakened  is  removed  as  shown 
by  the  stability  test.  Artificial  silk  which  had  been  heated  to  140°  F. 
with  sodium  acetate  solution  as  a  protective  agent,  then  well  rinsed  and 
dried  cold,  was  shown  to  be  slightly  improved  by  the  treatment. 

The  bleaching  of  artificial  silks  should  be  carried  out  rapidly,  and  the 
best  results  arc  obtained  Ijy  giving  alternate  baths  of  sodium  hypochlorite 
and  hydrochloric  acid.  The  permanganate  method  of  bleaching  cannot 
be  used  as  it  weakens  the  fiber. 

The  drying  of  artificial  silk  after  dyeing  or  bleaching  should  be  care- 
fully conducted;  overheating  (not  over  110°  F.)  should  be  avoided,  and 
the  silk  should  be  removed  from  the  drying  chamber  as  soon  as  it  is 
properly  dried. 

The  addition  of  Turkey-red  oil  (or  Monopol  oil)  is  frequently  made 
to  the  dyobath  for  promoting  the  even  distribution  of  the  color  and  also 
for  producing  a  soft  feel  on  the  silk.  For  producing  a  "  scroop  "  on  the 
fiber  the  silk  is  first  passed  through  a  soap  bath,  and  then  through  a  bath 
containing  a  small -quantity  of  acetic  or  tartaric  acid,  and  dried  without 
further  washing. 

In  tensile  strength  artificial  silk  shows  about  one-half  the  breaking 
strain  of  natural  silk;  its  elasticity  is  also  about  one-third  to  one-half 
that  of  the  latter,  as  shown  in  the  following  table: 


Silk. 

Breaking  Strain  per 
Denier  in  Grams. 

Elasticity, 
Percent. 

Natural  silk 

Chardonnet 

2.50 
0.93 
1,43 
1.64 
0.63 
1.40 

21.6 
8  0 

Lehner 

7.5 

Cuprammonium 

Gelatine 

Viscose 

12.5 

3.8 
9.5 

Bronnert  gives  the  following  table  of  comparisons  between  the  tensile 
strengths  of  modern  artificial  silks: 


PROPERTIES   OF   ARTIFICIAL  SILK 


713 


Tensile  Strength  in 
Grams  per  Denier 

Elasticity, 

Dry. 

Wet. 

Percent. 

Viscose 

Acetate 

Cuprate 

1.3-1.8 

1.3-1.4 

1.4 

0.4-0.8 
1.5 
0.55 

15 
20 
16 

Dreaper  reports  a  sample  of  cellulo  artificial  silk  of  25  denier  and 
composed  of  60  filaments  as  having  a  breaking  strain  of  2.3  grams  per 
denier.     This  is  practically  equivalent  to  natural  silk  in  strength. 

When  wetted  the  filaments  of  artificial  silk  show  a  loss  of  50-70 
percent  in  tensile  strength.  Bronnert  states  that  the  tensile  strengths  of 
the  various  artificial  silks  in  the  dry  state  are  about  the  same;  in  the  wet 
state  the  cuprate  silk  is  about  10  percent  stronger. 

The  luster  of  artificial  silk  is  one  of  its  chief  characteristics.  In  this 
respect  it  is  generally  superior  to  natural  silk.  Its  luster,  however,  is 
somewhat  metalhc  by  reason  of  double  refraction,  and  this  is  especially 
noticeable  in  the  case  of  collodion  silks.  Owing  to  this  property  of  double 
refraction  many  dyestuffs  fluoresce  to  such  an  extent  as  to  be  objection- 
able. Acetate  silk  does  not  have  the  high  luster  of  viscose  or  cuprate, 
and  more  nearly  approaches  real  silk  in  this  respect.  Owing  to  its  water- 
repellent  nature  it  does  not  absorb  moisture  as  readily  as  the  other  forms 
of  artificial  silk,  which  makes  it  somewhat  better  for  weaving. 

Ai'tificial  silk  is  more  hygroscopic  than  cotton;  in  fact  it  is  about 
equal  to  natural  silk  in  this  respect.  The  result  of  a  large  number  of  tests 
at  the  Elberfeld  conditioning  laboratory  shows  the  hygroscopic  moisture 
in  artificial  silks  to  vary  between  9.30  and  12.99  percent,  with  an  average 
of  11.3  percent.  The  valuation  of  artificial  silks  is  now  made  on  a  basis 
of  1 1  percent  of  moisture,  the  same  as  natural  silk. 

The  density  (specific  gravity)  of  cellulose  artificial  silks  is  about  1.56 
or  about  10-13,  percent  higher  than  natural  silk.  Acetate  silk  has  a 
density  of  1.25;  hence  it  is  about  6  percent  less  dense  than  real  silk  and 
about  17  percent  less  than  the  other  forms  of  artificial  silk. 

The  covering  power  of  artificial  silk  is  only  about  one-half  that  of  natu- 
ral silk,  this  being  chiefly  due  to  the  relatively  larger  size  of  the  individual 
filaments.  Owing  to  differences  in  the  structure  of  the  cross-section  of 
the  filament,  acetate  silk  does  not  have  the  same  covering  power  as  viscose 
or  cuprate  silk.  Dreaper  ^  enumerates  the  defects  of  artificial  silk  as 
compared  with  natural  silk,  as  follows:  (1)  The  size,  or  denier,  of  threads 
is  too  great;  (2)  the  individual  filaments  are  much  larger  than  those  of 
1  Jour.  Soc.  Dyers  &  Col,  1907,  p.  7. 


714  ARTIFICIAL  SILKS 

real  silk;  (3)  the  strength  and  especially  the  elasticity  are  not  satisfactory; 
(4)  the  loss  of  strength  on  wetting  is  excessive;  (5)  the  lack  of  covering 
power  reduces  the  value  of  the  products. 

10.  Comparison  of  Artificial  Silks. — Hassac  ^  gives  a  comparison  of 
several  makes  of  artificial  silk.  Chardonnet's  and  Lehner's  silks  are  very 
similar  in  appearance ;  they  are  more  lustrous  than  real  silk,  but  are  stiff er, 
and  do  not  possess  the  characteristic  feel.  Cellulose  silk  made  by  the 
ammoniacal  copper  oxide  process  is  similar  to  the  former  in  appearance, 
but  its  luster  is  even  better,  and  it  has  the  characteristic  feel  of  true  silk. 
Lehner's  silk  under  the  microscope  is  characterised  by  deep  longitudinal 
grooves  and  small  air-bubbles;  its  cross-section  is  highly  irregular.  Cu- 
prate  silk  shows  fine  longitudinal  grooves  and  minute  transverse  lines  in 
the  center  of  the  fibers;  its  cross-section  is  regular,  approaching  a  circle  or 
ellipse.  Hammel's  gelatine  silk  is  almost  circular  in  outline,  and  is  free 
from  grooves  and  bubbles;  in  polarised  light  it  is  singly  refracting,  while 
the  others  are  doubly  so.  When  viewed  in  polarised  light  under  the 
microscope  collodion  silk  shows  a  bright  blue  color,  whei'eas  viscose  and 
cuprammonium  silks  show  a  uniform  bluish  gray  color. 

There  seems  to  be  considerable  difference  in  the  amount  of  ash  in  the 
artificial  silks  of  different  origin.     Mitchell  and  Prideaux  give  the  following 

°  *  Percent. 

Collodion  silk 2.23 

Viscose  silk 0.28 

Cuprate  silk 0.18 

As  the  collodion  silks  always  contain  some  nitrated  compound,  they 
give  a  blue  color  with  diphenylamine  and  sulfuric  acid.  The  test  is  carried 
out  by  dissolving  a  small  portion  of  the  silk  sample  in  concentrated  sulfuric 
acid  to  which  has  been  added  a  trace  of  diphenylamine.  Collodion  silks 
will  give  a  bright  blue  color  immediately,  whereas  the  other  cellulose  silks 
furnish  only  a  slight  yellow  coloration.  In  place  of  diphenylamine, 
brucine  hydrochloride  may  be  used  in  the  same  manner,  in  which  case 
the  color  with  collodion  silk  is  a  bright  red.  The  other  cellulose  silks  give 
a  yellow  color.  Collodion  silks  will  usually  show  less  than  0.2  percent  of 
nitrogen;  ordinary  silk  contains  about  17  percent.  This  trace  of  nitrogen 
compound  is  sufficient,  however,  to  distinguish  collodion  silk  from  viscose 
and  cuprammonium  silks. 

Water  causes  all  the  artificial  silks  to  swell,  while  alcohol  or  glycerol 
contracts  them.  In  strong  sulfuric  acid  the  collodion  silks  swell  rapidly 
and  dissolve;  cuprate  silk  gradually  becomes  thinner  and  dissolves; 
gelatine  silk  only  dissolves  on  strong  heating.  Chromic  acid  dissolves  all 
artificial  silks  in  the  cold;  real  silk  dissolves  but  slowly,  while  cotton  and 
other  vegetable  fibers  are  unaffected.  Caustic  potash  does  not  dissolve  the 
1  Chem.  Zeit.,  1900,  pp.  235,  2G7,  297. 


COMPARISON   OF  ARTIFICIAL  SILKS 


715 


collodion  or  cellulose  silks,  but  both  the  gelatine  silk  and  real  silk  are 
soluble  on  boiling.  Schweitzer's  reagent  dissolves  collodion  and  other 
cellulose  silks;  whereas  gelatine  silk  is  insoluble  but  stains  the  liquid  a 
bright  violet.  Alkaline  copper-glycerol  solution  at  80°  C.  dissolves  real 
silk  immediately.  Tussah  and  gelatine  silks  dissolve  when  boiled  for  one 
minute;  the  other  silks  are  not  affected.  Iodine  solution  colors  artificial 
silks  an  intense  red,  which  changes  to  a  transient  pale  blue  on  washing 
with  water  in  the  case  of  collodion  silks,  though  cellulose  silk  does  not 
show  this  blue  color.  Iodine  and  sulfuric  acid  stain  true  silk  a  yellow 
color,  gelatine  silk  brown,  while  the  cellulose  silks  are  colored  blue. 

Cuprate  silk  is  distinguished  from  collodion  silk  by  its  very  low  copper 
index.  The  cellulose  of  which  cuprate  silk  is  composed  appears  to  be  of  a 
higher  degree  of  hydration  than  that  in  viscose  silk,  as  evidenced  by  the 
greater  solidity  of  this  latter  variety  in  the  moist  condition.  Cuprate  silk 
always  retains  traces  of  copper,  giving  the  fiber  a  milky  or  bluish  appear- 
ance; when  treated  with  ammonium  sulfide  it  gives  a  grayish  color. 
Cuprate  silk  is  also  somewhat  less  limpid  and  brilliant  than  viscose  silk. 
According  to  Bronnert,  viscose  and  cuprate  silks  may  be  recognised  by 
applying  a  few  drops  of  strong  sulfuric  acid  to  the  fibers;  cuprate  silk 
becomes  yellow,  and  develops  a  straw-colored  solution  which  increases  in 
intensity  to  a  brown  color;  viscose  silk,  on  the  other  hand,  will  imme- 
diately give  a  reddish  brown  color. 

Massot  gives  the  average  thickness  of  the  filaments  of  different  varieties 

of  artificial  silk  as  follows: 

Microns. 

Chardonnet  silk 28.8 

Lehner  silk 35 . 4 

Cuprate  silk 31.4 

Viscose  silk 30 . 5 

Genuine  silk 15.0 


Comparison  op  Different  Artificial  Silks  with  Real  Silk  (Hassac) 

Moisture. 

Fibers  to 

Tens.  Strength, 
Kilo,  per 

Sq.  Mm. 

Sq.  Mm. 

Elas- 

Sp.Gr. 

ticity, 

Silk. 

Per- 

Air- 

Satu- 

cent. 

dry, 

rated, 

Wet. 

Drv. 

Wet. 

Drv. 

Percent. 

Percent. 

Real  silk 

8.71 
11.11 

20  11 
27.46 

1.36 
1.52 

9710 
640 

9710 
1135 

37.0 

2.2 

37.0 
12.0 

21.6 

Chardonnet 

8.0 

(Walston) .  . 

11.32 

28.94 

1.53 

683 

1620 

1.0 

22.3 

7.9 

Lehner 

10.45 

26.45 

1.51 

413 

1180 

1.5 

16.9 

7.5 

Cuprate 

9.20 

23.08 

1.50 

742 

1550 

3.2 

19.1 

12.5 

Gelatine 

13.98 

45.56 

1.37 

265 

945 

0.0 

6.6 

3.8 

716 


ARTIFICIAL  SILKS 


Silbermann  gives  the  following  figures  for  the  elasticity  of  different  silks : 

Percent. 

Real  silk 17.2 

Tussah  silk 18.0 

Chardonnet  silk 11.6 

Vivier  silk 9.6 

It  is  claimed  that  the  elasticity  of  the  Thiele  cuprate  silk  is  practically 
equal  to  that  of  real  silk. 

According  to  Siivern  the  amount  of  moisture  in  air-dry  silks  is  as 

follows : 

Percent. 

China  raw  silk 7 .  97 

Tussah  silk 8 .  26 

Chardonnet  silk 10.37-11 .17 

Lehner  silk 10.71 

Cuprate 10.04 

Viscose  silk 11 .44 

Gelatine  silk 13,02 

Strehlenert  and  Westergren  give  the  following  figures  for  the  tensile 
strengths  of  various  natural  and  artificial  silks,  the  figures  indicating  the 
breaking  strains  in  kilograms  per  square  millimeter  section: 

Natural  Silks 


Chinese  silk 

French  raw  silk 

French  silk,  boiled  off 

' '  dyed  red  and  weighted 

"  blue-black,  weighted  110  percent 

"  black,  weighted  140  percent 

' '  black,  weighted  500  percent 


Dry. 


Wet. 


53.2 

46.7 

50.4 

40.9 

25.5 

13.6 

20.0 

15.6 

12.1 

8.0 

7.9 

6.3 

2.2 

Artificial  Silks 


Chardonnet's  collodion,  undyed 
Lenher's  collodion,  undyed .  .  .  . 
Strehlenert's  collodion,  undyed. 

Cuprate,  undyed 

Viscose  silk,  early  samples 

' '  latest  samples 

Cotton  yarn  (for  comparison) .  . 


Dry. 


14.7 

1.7 

17.1 

4.3 

15,9 

3.6 

19.1 

3.2 

11.4 

3.5 

21.5 

11,5 

18,6 

Wet. 


COMPARISON  OF  ARTIFICIAL  SILKS  717 

Cross  and  Bevan  ^  give  the  following  data  regarding  the  strength  of 
artificial  silks: 


Breaking  strain  per  unit  denier  (grams). 
Stretch  under  breaking  strain  (percent) . 
True  elasticity  (percent) 


Artificial  SUks. 


1.0-1.4 

13-17 

4-5 


True  Silk  Boiled-off . 


2.0-2.5 

15-25 

4-5 


In  contradistinction  to  the  general  opinion,  artificial  silk  withstands 
wear  and  rubbing  quite  well,  and  fabrics  of  artificial  silk  if  properly  handled 
will  stand  laundering  as  well  as  those  of  cotton.  Artificial  silk  linings  are 
said  to  be  better  than  those  of  Italian  cloth,  as  the  surface  is  so  smooth 
that  it  slips  easily  and  puts  the  burden  of  wear  on  the  other  fabric.  Arti- 
ficial silk  used  in  hosiery  stands  up  under  wear  about  as  well  as  cotton. 

The  commercial  sizes  in  which  artificial  silk  is  generally  employed  is 
from  119  to  150  denier  for  weaving  and  braiding;  coarser  numbers  are  used 
for  passementerie  articles,  etc.  By  the  Thiele  process  of  manufacture 
artificial  silk  threads  of  40  denier  and  even  less  may  be  produced,  each 
thread  consisting  of  80  filaments.  In  this  variety  of  silk  the  single  silk 
filament  is  finer  than  that  of  natural  silk  (|  to  1  denier),  and  this 
gives  the  thread  greater  elasticity  and  softness.  In  other  varieties  of 
artificial  silk  the  size  of  the  individual  filaments  averages  5  to  8  denier, 
or  about  twice  that  of  the  natural  silk  fiber.  Owing  to  its  structure  it  is 
also  claimed  that  Thiele's  silk  has  much  greater  strength  than  other  varie- 
ties of  artificial  silk;  its  strength,  in  fact,  being  only  20  percent  less  than 
that  of  real  silk. 

The  covering  power  of  artificial  silk  is  dependent  chiefly  upon  the 
surface  possessed  by  a  given  weight  of  thread,  and  again  upon  area  of  the 
cross-section  of  the  individual  filament  of  the  thread.  As  regards  the  size 
of  the  filaments,  the  cover  increases  as  the  size  decreases  in  proportion 
to  the  diameter  of  the  filaments,  so  that  of  two  threads  of  the  same  diam- 
eter, one  with  eighteen  filaments  the  other  with  thirty,  the  latter  would 
have  about  30  percent  more  cover  than  the  former.  The  weight  of  the 
filament,  however,  is  not  the  only  factor,  nor  does  the  specific  gravity  of 
the  various  silks  vary  sufficiently  to  be  taken  into  account,  but  the  shape 
of  the  cross-section  of  the  filaments  is  of  vital  importance  in  this  connection. 
A  filament  with  a  circular  section  has  less  covering  power  than  a  filament 
of  any  other  shape,  and  the  greater  the  departure  from  the  round  section 
the  more  effective  becomes  the  thread;  also  with  increased  surface  for 
the  reflection  of  light,  other  things  being  equal,  there  is  a  correspondingly 
improved  luster.  The  cross-sections  of  artificial  threads  vary  to  a  large 
^Jour.  Soc.  Chem.  hid.,  1908,  p.  1189. 


718  ARTIFICIAL  SILKS 

extent  and  can  be  varied  to  a  wide  range,  the  controlling  factors  being  the 
composition  of  the  cellulose  solution  and  the  strength  of  the  decomposing 
bath;  this  is  in  the  case  of  silk  of  the  viscose  or  cuprate  type.  Cellulose 
acetate  silk  being  spun  into  free  air  can  have  a  like  control  by  the  speed  at 
which  it  is  dried,  or,  in  other  words,  the  rate  at  which  the  acetone  is 
evaporated. 

With  regard  to  cost  of  manufacture  there  is  little  doubt  that  viscose 
silk  is  the  cheapest,  with  cuprate  silk  next,  and  collodion  and  acetate  silks 
are  the  most  expensive. 

11.  Microscopy  of  Artificial  Silks.^ — When  viewed  under  the  microscope 
artificial  silk  presents  mostly  a  smooth,  structureless  appearance,  resembling 
that  of  a  transparent  glass  rod.  The  appearance  is  quite  different  from 
that  of  the  other  textile  fibers,  and  usually  the  cross-sections  of  the  fibers 
are  quite  characteristic.  The  various  kinds  of  artificial  silk  may  usually 
be  distinguished  by  their  microscopic  characteristics. 

Herzog  gives  the  following  summary  of  the  microscopical  properties  of 
artificial  silks: 

1.  (a)  Between  crossed  Nicol  prisms  marked  brightening  of  the 

optical  field See  2 

(b)  Between  crossed  Nicol  prisms  little  or  no  brightening  of  the 

optical  field See  3 

2.  (a)  Stained  with  Congo  Red  strong  dichroism See  4 

(6)  Stained  with  Congo  Red  no  dichroism See  5 

3.  (a)  After  insertion  of  gyi:)sum  plate  red  appears 

with  +45°  addition  color. 

with  —45°  subtraction  color See  6 

(6)  As  in  (a)  reversed  after  insertion  of  mica  plate  the  fiber 
appears  between  parallel  Nicols 
with  +45°  white, 
with  —45°  brown. 
Mounted   in    citron   oil,    appears   almost   invisible;    ultra- 
microscopic  granular  structure  very  weak Acetate  Silk 

4.  (a)  Polarisation  colors  luminous  but  changing,  arranged  in  more 

or    less    parallel    striations;     ultramicroscopic    structure 

granular  b\it  rather  indistinct Collodion  Silk 

(b)  As  in  (a)  but  colors  not  so  pronounced  and  the  parallel 

striations  are  not  so  prominent;  ultramicroscopic  appear- 
ance shows  graiiulations  quite  marked Viscose  Silk 

(c)  Fiber  mass  shows  a  single  brownish  orange  color;   between 

parallel  Nicols  a  uniform  grayish  blue;   with  ultramicro- 

scope  very  marked  granulations Cuprate  Silk 

5.  (a)  Polarisation    colors    uniform    bluish   or   yellowish,    seldom 

reddish   violet;     with   ultramicroscope   strongly   marked 

parallel  structure True  Silk 

(b)  Polarisation  colors  various  and  rapidly  alternating  showing 
broad  band-like  fibrils;  with  ultramicroscope  parallel 
structure  very  apparent Tussah  Silk 


MICROSCOPY   OF  ARTIFICIAL  SILKS 


719 


6.  (a)  Double  refraction  shown  without  use  of  gypsum  plate,  simply 
by  stretching  or  squeezing  the  fiber;  with  Congo  Red  not 
diehroic;  mounted  in  clove  oil  almost  invisible;  with 
ultramicroscope  no  structure  shown,  only  impurities  are 

seen Gelatine  Silk 

{b)  Double  refraction  quite  weak,  but  may  be  observed  between 
crossed  Nicols  and  without  the  use  of  gypsum  plate; 
stained  with  Congo  Red  not  diehroic;  natural  color 
yellowish  to  brownish  yellow Mussel  Silk 

According  to  Cross,  the  contour  of  the  silk  filament  is  quite  distinctive 
with  the  process  of  manufacture.  The  contour  is  governed  by  the  manner 
in  which  the  original  cylinder  of  cellulose  solution  contracts  during  the 
operations  of  coagulation  and  dehydration.  Three  broad  classes  of  section 
may  be  distinguished: 

(1)  The  whole  filament  contracts  slowly  and  evenly,  giving  a  fairly 
regular  section,  corresponding  to  cuprate  silk  (also  the  early  form  of 
viscose  silk  (Fig.  278). 


Fig.  278. — Cross-sections  of  Cuprate 
Silk.     (Cross.) 


Fig.  279. — Cross-sections  of  Collodion 
Silk.     (Cross.) 


(2)  The  outline  remains  smooth  while  ine  walls  contract  inward,  giving 
an  irregular  shape  with  a  smooth  surface,  corresponding  to  collodion  and 
acetate  silks  (Figs.  279  and  280). 

(3)  The  walls  become  corrugated  in  an  attempt  to  adjust  the  original 
circumference  to  a  diminished  sectional  area,  corresponding  to  modern 
viscose  silk  (Fig.  281). 

A  new  method  for  examining  the  cross-section  of  artificial  silk  fibers  is 
described  by  Herzog  ^  which,  it  is  claimed,  enables  even  an  inexperienced 

1  Deutsche  Faserstoffe,  1921,  p.  52. 


720 


ARTIFICIAL  SILKS 


observer  to  make  this  examination  in  about  a  minute,  as  it  avoids  the 
necessity  of  preparing  and  embedding  fine  sections.  The  bundle  of 
fibers  to  be  examined  is  treated  with  4  percent  collodion,  to  prevent  spread- 
ing of  the  fibers,  and  then  cut  across  with  a  sharp  knife  against  a  glass 
surface.  The  section  is  placed  against  a  side  of  a  right-angled  prism,  the 
hypotenuse  of  which  is  silvered,  in  the  direction  of  the  light.  The  prism 
acts  as  a  total  reflector,  and  the  section  is  examined  microscopically 
through  the  third  face  of  the  prism. 

12.  Ultramicroscopic  Studies  of  Artificial  Silk. — By  the  ordinary  proc- 
esses of  microscopy  it  is  not  possible  to  distinguish  structural  elements 
of  a  smaller  size  than  0.2  micron.  During  rather  recent  years,  however, 
the  study  of  colloids  has  developed  a  method  of  examination  known  as 
ultramicroscopy  and  a  number  of  investigators  have  applied  this  technique 


Fig.  280. — Cross-sections  of  Acetate 
Silk.     (Cross.) 


Fig.  281. — Cross-sections  of  Modern 
Viscose  Silk.     (Cross.) 


to  the  examination  of  textile  fibers  and  more  particularly  to  artificial  silks 
(Siedentopf,  Schneider  and  Kunzl,  Gaidukov,  and  Herzog).^  By  the  use 
of  the  ultramicroscope  (Fig.  282)  magnifications  up  to  2500  can  be  ob- 
tained and  considerable  light  is  thrown  on  the  minute  inner  structure  of 
many  bodies.  When  examined  by  ultramicroscopic  methods  the  artificial 
silks  exhibit  certain  well-defined  differences  among  themselves  and  also 
from  such  other  fibers  as  true  silk,  tussah  silk,  and  cotton.  Cuprate, 
viscose,  and  collodion  silks  show  a  granulated  structure,  but  these  granules 
are  different  in  size  and  form  (Figs.  283,  284,  and  285).  The  results  with 
acetate  silk  are  not  very  satisfactory,  but  as  this  variety  of  silk  can  be  so 

1  Schneider  and  Kunzl,  "Spinnfasern  und  Fiirbungen  im  [Jltramikroskop,"  Zi-iUchr. 
f.  c'is.s.  Mikrosk.,  vol.  24,  No.  4;  Gaidukov,  "Ueber  die  Anwendung  des  Uitrami- 
kroskopes  in  der  Textil-  und  Farbstoff -Industrie,"  ZeiUchr.f.  ang.  Chemie,  1908. 


USES  OF  VARIOUS   CELLULOSE  SOLUTIONS 


721 


readily  distinguished  by  other  more  obvious  means  it  does  not  come 
into  consideration  here.  Gelatine  silk  is  optically  clear  and  gives  no 
results  with  the  ultramicroscope,  but  as  this  silk  is  of  little  or  no  com- 
mercial importance  at  the  present  time  it  may  also  be  left  out  of  con- 
sideration. True  silk  and  tussah  silk  both  show  a  distinct  parallel  struc- 
ture with  the  ultramicroscope  (Figs.  286  and  287)  while  cotton  shows  an 
apparently  laminated  structure  (Fig.  288). 

13.  Uses  of  Various  Cellulose  Solutions. — Silklike  filaments  may  be 
obtained  from  a  solution  of  ce^Mose  in  zinc  chloride.^  The  liquid  may  be 
easily  spun,  but  the  thread  which  is  formed  is  too  weak  to  be  employed 
as  a  substitute  for  silk.     The  solution  is  principally  used  for  the  manu- 


FiG.  282. — Apparatus  for  the  Ultramicroscopic  Examination  of  Fibers. 

facture  of  filaments  for  incandescent  electric  lamps.     A  better  solution  is 
obtained  by  using  alkali-cellulose  in  place  of  cellulose  (Bronnert) . 

Foltzer  points  out  the  fact  (Textile  Manufacturer)  that  ordinary  cellu- 
lose is  only  slightly  soluble  in  cold  zinc  chloride,  in  which  it  becomes  a 
gelatinous  substance;  a  real  solution  is  obtained  only  with  a  high  tempera- 
ture. Without  doubt  the  zinc  chloride,  by  its  hydrating  action,  produces 
depolymerisation  of  the  cellulose,  such  that  the  substance  precipitated 
possesses  only  in  a  slight  degree  the  characteristic  properties  of  cellulose. 
Wynne  and  Powell  have  tried  to  replace  the  zinc  chloride  by  a  mixture  of 
zinc  chloride  and  aluminium  chloride.  It  is  possible  that  depolymerisation 
may  be  retarded  somewhat  in  this  manner;  but  Wynne  and  Powell,  as  well 
as  Dreaper  and  Thomson — who  have  also  proposed  to  employ  cellulose 
dissolved  in  zinc  chloride  to  produce  a  textile  thread — have  been  able  to 
obtain  this  solution  only  by  raising  the  zinc  chloride  to  a  high  temperature. 

1  Dreaper  and  Thomson  [Brit.  Pal.  17,901  of  1898).  The  sohition  of  cellulose  in 
zinc  chloride  is  forced  through  jets  into  alcohol  or  acetone,  which  coagulates  the 
cellulose. 


722 


ARTIFICIAL  SILKS 


However,  It  has  been  stated  that  during  these  processes  the  molecular  con- 
stitution of  the  cellulose  is  changed,  and  the  threads  thus  formed  are 
exceedingly  weak.  In  an  American  patent,  Bronnert  describes  a  method 
which,  so  far  as  we  know,  has  not  yet  passed  beyond  the  experimental 
state;  according  to  this  method,  it  would  be  possible  to  obtain  a  strong 
thread  by  subjecting  the  cellulose  to  prehminary  processes  before  dissolving 


Fig.  283. — Structure  of  Cuprate  Silk  under  Ultramicroscope. 


H'^ 

Fig.  284. — Structure  of  Viscose  Silk  under  Ultramicroscope. 


Fig.  285. — Structure  of  Collodion  Silk  under  Ultramicroscope. 

it  in  zinc  chloride,  just  as  was  done  for  the  cellulose  dissolved  in  an  ammo- 
niacal  solution  of  copper  oxide. 

The  most  advantageous  method  consists  in  transforming  the  scoured 
and  bleached  cellulose  into  soda  cellulose  by  immersing  it  in  a  cold  bath 
of  concentrated  caustic  soda,  then  decomposing  the  soda  cellulose  with 
water,  and  finally  in  dissolving  the  cellulose  thus  obtained  in  a  concen- 
trated solution  of  zinc  chloride.     The  solutions  prepared  in  this  maimer 


USES   OF  VARIOUS   CELLULOSE  SOLUTIONS 


723 


must  be  kept  in  tanks  and  at  a  low  temperature,  so  as  to  prevent  any 
decomposition  which  would  be  detrimental  to  good  spinning,  and  might 
even  make  this  operation  impossible.     A  new  process,  and  one  which 


Fig.  2SG. — Structure  of  True  Silk  under  Ultramicroscope. 


Fig.  287. — Structure  of  Tussah  Silk  under  Ultramicroscope. 


Fig.  288. — Structure  of  Cotton  Fiber  under  Ultramicroscope.     (X1400.) 


appears  to  have  a  future,  is  that  of  the  alkali  cellulose  by  Bcltzer,  of  Paris. 
When  wood-pulp  is  introduced  uniformly  into  a  caustic  soda  lye  of  10°  Be. 
and  at  a  temperature  of  32°  to  41°  F.  hydration  takes  place;   an  almost 


724  ARTIFICIAL  SILKS 

complete  solution  is  obtained  only  when  the  temperature  is  lowered  to 
14°  F.  With  these  solutions  of  alkali  cellulose  the  inventor  has  been  able 
to  produce  artificial  silk,  pellicles,  etc.  Again,  Beltzer  observes  that,  like 
solutions  of  caustic  soda,  sulfuric  acid,  phosphoric  acid,  etc.,  when  employed 
at  the  proper  concentration,  mercerise  or  hydrate  cellulose.  Sulfuric  acid, 
for  example,  at  49°  to  55°  Be.,  transforms  cellulose  into  a  parchment- 
like substance  which  dissolves  in  the  cold  and  forms  a  viscous,  homogeneous, 
and  transparent  mass.  This  solution  is  termed  amyloid  because  of  its 
resemblance  to  amidon  (starch).  The  same  result  is  obtained  by  treating 
cotton  cellulose  or  wood  pulp  with  zinc  chloride,  or  with  phosphoric  acid 
at  a  certain  concentration.  The  action  of  these  agents  on  cellulose  has  been 
known  for  a  considerable  time;  but  it  has  been  left  for  J.  G.  Beltzer  to 
make  experiments  at  low  temperatures  of  32°  to  14°  F.,  by  which  he  has 
been  able  to  prevent  hydrolysis  and  destruction  of  the  cellulose.  As  soon 
as  a  gelatinous  solution  of  hydrated  cellulose  is  obtained  at  this  low  tem- 
perature, the  solution  is  diluted  with  cold  water,  preferably  with  ice,  to 
avoid  too  great  a  rise  in  temperature.  It  then  forms  a  precipitate  of 
hydrated  cellulose,  which  is  washed  in  water,  or  in  a  bath  which  is  slightly 
alkaline,  to  remove  the  acid;  after  a  final  washing  with  cold  water  a  pure 
hydrated  cellulose  is  obtained  which  dissolves  completely  in  caustic-soda 
lye. 

14.  Artificial  Horsehair. — It  has  already  been  mentioned  that  arti- 
ficial horsehair  has  been  prepared  in  a  manner  similar  to  artificial  silk  by 
spinning  coarse  filaments  (300-400  denier)  of  the  cellulose  solutions. 
Threads  of  sUk,  cotton,  and  linen  are  also  coated  with  a  layer  of  collodion 
or  other  cellulose  solution  to  form  lustrous  silk-like  yarns.^  Silk  fish-lines 
coated  in  this  manner  with  pyroxylin  and  dyed  a  light  green  gives  a  thread 
which  is  impermeable  to  water,  has  a  tendency  to  float,  and  is  practically 
invisible  beneath  water. 

Crinol  is  the  name  given  to  an  artificial  hair  prepared  from  cupram- 
monium  cellulose;  meteor  is  a  name  for  a  similar  article. 

15.  Staple  Fiber  and  Fibre. — During  the  recent  war  there  was 
developed  an  artificial  silk  product  in  Germany  known  as  "  staple  fiber." 
Very  fine  artificial  silk  fibers  are  twisted  into  thick  threads  and  these  are 
cut  into  lengths  of  4  to  5  cm. ;  the  fine  fibers  separate  out  again  and  are 
spun  into  yarns,  sometimes  alone,  but  mostly  in  connection  with  wool 
or  other  fibers.  Yarns  of  staple  fiber  were  used  very  largely  for  apparel 
fabrics.  Fibro  is  an  artificial  silk  product  of  British  manufacture;  it 
consists  of  short  lengths  of  the  fibers  and  is  employed  for  the  spinning  of 
specialty  yarns  and  fabrics  requiring  a  high  degree  of  luster.     It  is  being 

1  A  close  imitation  to  natural  black  horsehair  is  prepared  by  coating  a  50's  six-cord 
black  thread  with  a  suitable  pyroxylin  solution.  The  coated  thread,  while  still  black 
has  a  peculiar  superficial  transparency  which  is  so  noticeable  in  the  natural  hair. 


MINOR  USES  OF  CELLULOSE  SOLUTIONS         725 

produced  in  increasing  amounts  as  a  self  fiber  and  is  not  used  as  a  substi- 
tute for  wool. 

16.  Ribbon  Straw  from  Artificial  Silk. — This  is  made  by  forming  the 
artificial  silk  solution  into  a  thin  ribbon  instead  of  a  fine  filament.  The 
ribbons  are  generally  1  to  5  mm,  in  width  and  about  0.02  mm.  in  thick- 
ness. The  cellulose  solution  is  projected  through  a  slit-shaped  aperture 
into  the  coagulating  bath.  The  product  is  highly  lustrous,  dyes  readily 
and  is  cxtensivel}^  used  in  hat  making  and  fancy  work. 

17.  Minor  Uses  of  Cellulose  Solutions. — Foltzer  (Textile  Manufac- 
turer) calls  attention  to  other  uses  of  viscose  independent  to  its  transforma- 
tion into  artificial  silk,  as  follows: 

(I)  Decorative  painting  with  cellulose  as  base:  The  collective  power 
of  dissolved  cellulose  (viscose),  which  is  capable  of  retaining  nearly 
twenty  times  its  weight  of  mineral  powder,  is  very  suitable  for  forming 
the  base  of  a  paint  which,  due  to  the  stability  of  cellulose,  resists  success- 
fully atmospheric  influences.  This  paint  adheres  perfectly  to  plaster 
even  before  the  latter  is  perfectly  dry;  to  wood,  cements,  and  even  to 
felt  and  bitmnen  boards.  It  is  incombustible,  and  yields  a  smooth  and 
homogeneous  surface  which  can  be  washed  with  soda  a  few  days  after  the 
paint  has  been  applied. 

(II)  Paper  for  art  impressions:  The  characteristic  features  of  paints 
with  cellulose  as  base  render  them  particularly  suitable  for  the  manufac- 
ture of  paper  for  art  impressions;  a  surface  of  remarkable  smoothness 
and  exceptional  softness  can  thus  be  obtained,  upon  which  it  is  possible 
to  engrave  figures  possessing  that  finish  which  is  typical  of  high-class 
reproductions. 

(III)  Lining  or  covering  for  fabrics:  Employed  pure  or  slightly 
loaded,  viscose  forms  on  the  surface  of  fabrics  a  very  homogeneous  layer, 
which  is  insoluble  in  water,  and  which  resists  effectively  the  action  of  acids 
and  alkalies;  transparent  viscose  can  be  used  on  cloth  for  shades,  and 
opaque  viscose  used  on  cloth  for  waterproof  bed  covers  and  for  book- 
binding. AMien  prepared  for  the  latter  purpose  it  forms  a  surface  which 
is  admirably  adapted  for  engraving  and  goffering. 

(IV)  Viscose — India  rubber:  Viscose  mixed  with  india  rubber  is  a 
cheaper  substance  than  pure  rubber,  and  may  be  used  for  practically  all 
purposes  for  which  rubber  has  formerly  been  used — e.g.,  waterproof 
garments,  tubes,  etc.  In  combination  with  viscose,  india  rubber  resists 
atmospheric  action  better,  and  its  flexibility  is  entirely  preserved. 

(V)  Embossing  and  finishing  effects  on  fabrics  and  threads:  Viscose 
can  be  used  very  economically  as  a  layer  for  receiving  color  impressions, 
especially  white.  On  fabrics  or  threads  it  forms  a  cellulose  finish  which 
is  unaffected  by  washing.  In  dyeing,  viscose  forms  a  mordant  for  certain 
coloring  matters,  thus  effecting  an  economic  use  of  dyewares, 


726  ARTIFICIAL  SILKS 

(VI)  Papers,  cardboard:  Employed  in  the  manufacture  of  cards  and 
of  stout  paper  for  packing  purposes,  viscose  adds  additional  strength, 
which  varies  from  30  to  100  percent  according  to  the  compositions  of  the 
mixture.  In  a  similar  way  viscose  leather  papers  or  mock-leathers  have 
been  made. 

(VII)  Compressed  viscoid:  In  virtue  of  its  adherent  qualities  viscose 
yields  compact  substances  of  every  form.  This  product  is  an  excellent 
insulating  substance  for  heat  and  electricity,  and  is  known  by  the  name 
"  Viscoid." 

(VIII)  Various  industrial  substances:  Transparent  films  of  all  colors 
for  various  purposes  have  been  made  from  viscose;  packing  papers  for 
soap  and  similar  fatty  substances;  transparencies  for  use  as  imitation 
stained  glass  windows  and  other  purposes;  colored  balloons  or  globes  for 
electric-light  illumination;  thick  and  strong  films  for  replacing  celluloid 
in  numerous  ways. 

18.  Lace  and  Tulle  from  Cellulose  Solutions. — A  product  very  closely 
related  to  artificial  silk,  though  not  spun  into  a  fiber  or  filament,  is  the 
artificial  lace  made  from  solutions  of  cellulose,  the  cuprammonium  solution 
being  usually  employed. 

According  to  J.  Foltzer,  the  idea  of  manufacturing  tulle  and  lace  without 
having  recourse  to  spinning  and  weaving  was  first  developed  in  1899  by 
Adam  Millar,  of  Glasgow,  who  constructed  an  apparatus  for  this  purpose. 
Solutions  of  cellulose  or  other  viscous  substances  were  forced  through 
capillary  tubes  on  to  an  endless  cloth.  As  the  viscous  liquid  flowed 
through  the  capillary  tube  it  hardened.  The  movement  of  the  distributors 
was  adjusted  so  that  the  outer  edges  of  each  sinuous  band  joined  the  outer 
edges  of  the  neighboring  sinuous  bands  at  regular  intervals,  became 
attached,  and  thus  formed  an  artificial  tuUe  with  regular  meshes.  Accord- 
ing to  the  nature  of  the  cellulose  solution  or  the  viscous  liquid  employed, 
it  was  necessary  to  coagulate  the  threads  on  the  endless  cloth,  or  to  dry 
them  by  means  of  steam.  This  tulle  could  then  be  made  waterproof, 
or  receive  other  supplementary  treatment.  By  varying  the  speed  of  the 
endless  cloth  and  the  to-and-fro  movement  of  the  capillary  tube  it  is 
possible  to  vary  the  character  of  the  meshes. 

In  1901  another  patent  was  taken  out  by  Joseph  Mugnier,  of  Lyons, 
for  the  manufacture  of  artificial  tulle.  This  consisted  of  the  preparation 
of  a  special  solution,  to  which  the  inventor  added  glycerol  and  other 
products,  which  augmented  the  viscosity  of  the  solution  and  added  to  the 
flexibility  and  strength  of  the  product.  Still  another  idea  is  that  due  tb 
Emile  Duinat,  in  1906,  in  his  French  patent  No.  368,398.  The  solution 
of  cellulose  is  forced  through  a  rectangular  slot,  in  which  rise  and  fall 
one  or  more  sets  of  grips  in  the  form  of  teeth;  these  teeth  divide  or  inter- 
rupt the  continuous  flow  of  the  solution,  and  the  latter  consequently 


LACE  AND  TULLE  FROM  CELLULOSE  SOLUTIONS 


727 


emerges  In  the  form  of  fine  bands  or  ribbons,  or  of  thick  threads,  and  thus 
produces  a  kind  of  artificial  tulle. 

The  simplest  idea,  however,  as  well  as  the  most  practicable,  for  the 
manufacture  of  this  artificial  tulle  is  that  invented  by  Marius  Ratignier, 
Director  of  la  Societe  H.  Pervilhac 
et  Cie.,  Lyons.  The  process  of 
Ratignier-Pervilhac  gives  a  continu- 
ous arrangement  which  enables  one 
to  manufacture  indefinite  lengths  of 
this  new  product. 

The  apparatus  is  shown  in  Fig. 
289.  The  solution  of  cellulose  in 
the  correct  degree  of  viscosity  is  in 
the  tank  (A)  and  flows  uniformly 
on  to  the  engraved  cyhnder  (B)  Yig.  289.— Apparatus  for  Making  Artificial 
which  rotates    in    the    direction   of  Tulle, 

the    arrow.      All    the   parts   which 

form  the  design  are  thus  filled  with  the  solution,  and  a  thin  layer  may  also 
be  deposited  on  the  remaining  or  plain  parts  of  the  cylinder.  This  thin 
layer  is  removed  by  the  knife  or  scraper  (C).  A  coagulating  liquid 
is  forced  from  the  pipe  (D)  and  impinges  against  the  cylinder  in  its 
full  width;  the  surplus  liquid  falls  into  the  bath  (E)  and  thus  serves  to  com- 
plete the  coagulation,  while  the  bath  is  kept  at  a  constant  depth  by  means 

of  the  overflow  pipe  (F).  The 
coagulating  liquid  is  caught  as 
it  emerges  from  the  pipe  and  used 
again.  The  artificial  silk  product 
is  removed  from  the  cylinder  by 
an  endless  cloth  (G)  which  travels 
in  the  direction  indicated,  and  the 
tulle,  lace,  or  the  like  is  finally 
wound  on  to  a  suitable  drum. 
A  jet  of  water  from  the  pipe 
(H)  flows  over  the  full  width  of 
the  engraved  cylinder  and  thus 
removes  the  chemical  substances, 
while  the  recesses  in  the  cylinder 
are  dried  by  a  current  of  warm 
air  from  (J).  The  process  is  thus  continuous,  and  any  suitable  design 
may  be  engraved  on  the  metal  cylinder.  An  enlarged  view  of  the 
meshes  of  this  artificial  tulle  is  shown  in  Fig.  290. 

A  great  quantity  of  very  beautiful  artificial  tulle  is  now  made.     At 
first  sight  it  is  difficult  to  distinguish  it  from  ordinary  tulle.     The  artificial 


Fig.  290. — Artificial  Tulle  Showing  Forma- 
tion of  Meshes. 


728  ARTIFICIAL  SILKS 

product  is  naturally  less  pliable  than  tulle  made  from  ordinary  textile 
threads,  and  it  is  also  weaker;  it  has  the  luster  of  artificial  silk,  and  may 
be  metallised  or  waterproofed.  The  product  has  been  employed  mostly 
for  millinery  purposes.  It  has  been  manufactured  largely  by  la  Cie. 
frangaise  des  Applications  de  la  Cellulose,  at  Fresnoy-le-Grande,  and  is 
also  manufactured  in  the  United  States. 

In  the  Swiss  patent  No.  57,951  (1911),  la  Cie.  des  Applications  de  la 
Cellulose  gives  a  formula  for  a  special  solution  of  cellulose  for  the  manufac- 
ture of  artificial  tulle.  The  method  of  preparation  is  as  follows:  30  kilos, 
of  cleaned  and  partially  bleached  cotton  is  pulverised  in  a  suitable  machine 
until  all  the  fibers  of  cotton  are  reduced  to  powder.  To  this  pulverised 
cotton  is  added  a  sufficient  quantity  of  water  to  make  up  the  total  volume 
of  cotton  and  water  to  3000  liters.  Then  60  kilos,  of  crystallised  copper 
sulfate  is  dissolved  in  300  to  400  liters  of  water,  and  to  this  solution  is 
added,  little  by  little,  40  liters  of  caustic  soda.  The  two  solutions  are  then 
mixed,  and  the  cellulose  absorbs,  almost  immediately,  all  the  hydroxide 
of  copper.  The  surplus  liquid  is  now  removed  by  a  hydrocxtractor,  by 
pressure,  or  by  filtration,  and  the  residue  of  cellulose  charged  with  hydrox- 
ide of  copper  is  cut  up  into  slices.  This  substance  is  then  dissolved  in 
100  liters  of  ammonia  at  28°  Be.  It  is  then  left  to  work  up  for  fifteen 
to  twenty  minutes,  and  then  allowed  to  stand  for  twenty-five  hours. 
Finally,  the  mixer  is  restarted,  and,  with  the  object  of  completing  the 
solution,  about  0.6  liter  of  caustic  soda  at  38°  Be.  is  added  for  each  kilo- 
gram of  dissolved  cellulose.  The  preparation  of  this  solution  of  cellulose 
is  conducted  at  the  ordinary  temperature. 

In  the  British  patent  No.  11,714  (1911)  la  Cie.  des  AppHcations  de  la 
Cellulose  describes  a  process  of  coagulating  artificial  tulle  in  a  caustic 
soda  bath.  When  cellulose  dissolved  in  ammoniacal  copper  oxide  is 
precipitated  in  an  acid  bath  the  acid  removes  almost  immediately  practi- 
cally all  the  copper  from  the  precipitated  product,  and  leaves  the  substance 
nearly  white;  whereas,  if  caustic  soda  or  caustic  potash  is  used  for  pre- 
cipitation, the  copper  is  only  partially  removed,  and  the  product  thread 
or  tulle,  is  blue.  In  order  to  remove  the  rest  of  the  copper,  it  is  neces- 
sary to  pass  the  product  through  a  dilute  acid.  Again,  in  employing 
alkalies  for  coagulation,  the  coagulating  liquids  themselves  take  on  a 
deep  blue  color  in  consequence  of  the  presence  of  part  of  the  copper  which 
has  been  removed  during  the  coagulation. 

In  the  manufacture  of  artificial  silk  this  deep  color  formation  is  a 
disadvantage,  for  it  prevents,  to  some  extent,  the  operatives  from  seeing 
the  thi'ead  clearly,  and  from  controlling  successfully  the  formation  of  the 
thread — a  disadvantage  which  does  not  exist  when  coagulation  is  per- 
formed in  acid  baths.  Such  a  disadvantage  is  increased  in  connection 
with  the  manufacture  of  artificial  tulle,  for  it  is  necessary  to  see  continually 


LACE  AND  TULLE  FROM   CELLULOSE  SOLUTIONS  729 

if  the  tulle  is  properly  made,  and  to  make  sure  that  no  meshes  remain  in  the 
engraved  parts  of  the  cylinder.  The  above  French  company  has  been 
able  to  prevent  the  deposition  of  copper  in  the  liquid  by  adding  to  the 
alkaline  coagulating  bath  10  grams  of  commercial  white  arsenious  acid 
(AS2O3)  per  hter  of  caustic  soda  of  30  percent,  and  keeping  the  mixture 
at  a  temperature  of  140°  to  149°  F.  The  presence  of  the  arsenious  acid 
prevents  the  elimination  of  copper,  and  the  soda  bath  remains  clear  and 
uncolored  even  after  having  been  used  for  a  month.  On  the  other  hand, 
the  threads  or  tulle  contain  all  the  copper,  and  are  therefore  of  an 
intense  blue  color.  The  threads  are  wound  on  spools  and  the  tulle  on 
cylinders,  then  washed  to  remove  the  alkali,  and  finally  the  product  is 
readily  freed  from  copper  in  dilute  sulfuric  acid  at  5°  Be.  without  any 
precipitate  of  cupro-arsenious  products.  The  products  obtained  in  this 
way  are,  when  dry,  distinguished  by  their  brilliancy,  pliability,  and 
elasticit3^ 

Another  unique  process  for  the  manufacture  of  artificial  tulle  and  lace 
is  that  described  by  Joseph  Foltzer  (Swiss  patent  No.  69,514,  October, 
1913):  Method  of  making  artificial  textile  products  from  solutions  of 
cellulose  or  plastic  substances,  nitro-cellulose,  viscose,  cellulose  of  acetyl, 
and  the  like;  casein,  fibrine,  maizine,  and  the  like;  or  from  rubber. 
These  solutions  or  substances  are  apphed  as  thin  layers,  corresponding 
to  the  thickness  of  the  desired  body,  by  means  of  a  spreading  apparatus 
which  deposits  the  substance  on  to  a  cylinder,  an  endless  cloth,  or  some 
such  suitable  receptable.  The  substance  applied  to  the  cylinder  is  stemmed 
in  front  of  an  engraved  pressure  or  goffering  roll  which  is  placed  either 
close  to  or  at  a  short  distance  from  the  laying-on  or  spreading  apparatus. 
This  roll,  which  is  positively  driven  and  which  presses  against  the  cyhnder, 
stamps  out  the  viscous  mass  in  forms  which  coincide  with  the  engraving 
on  the  goffering  roll. 

The  work  may  be  performed  by  the  methods  illustrated  in  Fig.  291. 
The  solution  of  cellulose  or  viscous  mass  contained  in  the  spreading  appa- 
ratus (A)  escapes  on  to  the  cylinder  (D)  as  a  layer  which  corresponds  in 
thickness  to  the  depth  of  the  engraved  parts  in  the  goffering  roll  (B). 
The  rollers  rotate  as  indicated,  and  two  wings  or  blades  (E)  which  con- 
nect the  laj'ing-on  apparatus  to  the  roll  prevent  the  substance  from  escaping 
at  the  sides.  The  solution  is  fed  toward  the  grip  of  the  roll  and  the  cyl- 
inder, but  cannot  proceed  farther  as  a  body.  The  engraved  parts  on 
the  roll  representing  the  design  for  tulle  or  other  textile  texture,  become 
filled  with  the  solution  in  virtue  of  the  pressure,  and  by  this  time  the 
substance  is  partially  set  so  that  it  may  be  conveyed  farther  upon  the 
circumference  of  the  cylinder  and  immersed  in  a  hardening  liquid  contained 
in  the  tank  (C).  Soon  after  the  formed  fabric  emerges  from  the  bath  it  is 
detached  from  the  cylinder  by  means  of  the  rollers  (F).     It  is  then  guided 


730 


ARTIFICIAL  SILKS 


by  rollers  {G,  H,  J,  and  K)  into  and  out  of  the  three  vats  (L,  M,  and  A'') 
which  contain  suitable  liquids  for  the  further  treatment  of  the  product, 
as,  for  example,  precipitation,  acidification,  and  cleansing.  The  finished 
fabric  is  finally  wound  upon  a  reel  (P). 

It  has  been  found  in  practice  that  the  stamped  or  pressed-out  artificial 
products  adhere  very  frequently  to  the  engraved  parts  of  the  pressure  roll 
from  which  they  can  be  detached  only  with  difficulty.  This  is  particularly 
the  case  when  thick  embroidery  is  being  made.  To  prevent  this  annoying 
feature,  the  roll  is  sprayed  with  a  liquid  at  (Q)  which  precipitates  the 
solution,  while  the  excess  liquid  is  removed  by  the  stripping-knives  (R). 
The  adhering  of  the  substance  to  the  engraved  parts  of  the  roller  might 
also  be  prevented  by  heating  the  roller  to  that  temperature  which  causes 


Fig.  291.— Installation  for  Making  Artificial  Lace.     (Foltzer.) 


a  superficial  coagulation.  The  outer  surface  of  the  cylinder  must  also  be 
cleaned  very  carefully  between  the  rollers  and  the  outlet  of  the  spreading 
appaiatus.  For  this  purpose  is  provided  the  receptable  (S),  the  lateral 
outlet  pipe  (F),  and  the  pipe  (  U),  through  which  may  pass  a  cleansing 
liquid.  As  is  indicated,  the  lateral  walls  of  the  receptable  act  as  stripping- 
knives,  while  a  heated  drum  (F)  dries  the  surface  of  the  cylinder.  Special 
effects  may  be  obtained  if  fine  fibrous  powder,  either  of  one  color  or  of  differ- 
ent colors,  be  mixed  with  the  solution  of  cellulose,  or  if  such  powder  be 
sprinkled  on  the  roller  to  enable  it  to  atlhere  to  the  surface  of  the  substance 
when  the  latter  is  stamped  out.  In  order  to  impart  a  suitable  surface 
to  the  products,  liquid  gum,  tallow,  fine  metallic  powder,  and  the  like  may 
be  used. 

19.  Animalised    Cotton.— Cotton    may    be    "  animalised  "—that    is, 
given  the  dyeing  properties  possessed  by  animal  fibers— in  a  variety  of 


STATISTICAL  731 

ways.  The  material  may  be  impregnated  with  albumen  and  afterward 
steamed;  this  method  is  employed  to  some  extent  in  printing,  being  used 
chiefly  in  connection  with  the  direct  cotton  colors  to  prevent  their  bleeding. 
A  solution  of  casein  may  also  be  used  instead  of  albumen,  with  similar 
results.  The  same  property  may  also  be  imparted  to  cotton  by  treatment 
with  tannic  acid  and  gelatine  or  lanuginic  acid  (solution  of  wool  in  caustic 
alkali),  but  with  doubtful  results;  though  Knecht  describes  a  method  which 
is  said  to  give  satisfaction,  the  cotton  being  impregnated  with  a  solution  of 
lanuginic  acid  and  allowed  to  dry  in  the  presence  of  formaldehyde,  when 
the  fiber  becomes  coated  with  an  insoluble  film  possessing  a  remarkable 
affinity  for  the  substantive  dyes.  Vignon  claims  that  by  treating  cotton 
under  pressure  with  ammonia  in  presence  of  zinc  chloride  or  calcium 
chloride,  the  fiber  acquires  an  increased  affinity  for  the  basic  and  acid  dye- 
stuffs.     His  results,  however,  have  not  been  confirmed. 

A  silklike  appearance  may  also  be  given  to  vegetable  fibers  by  treat- 
ment with  a  solution  of  silk  (fibroin)  in  some  suitable  solvent,  such  as 
hydrochloric,  phosphoric,  or  sulfuric  acid,  or  cuprammonium,  etc.  The 
silk  employed  is  made  up  of  scraps  and  waste  which  would  otherwise  be 
useless.  Better  results  are  obtained  if  the  cotton  material  be  treated  with 
a  metallic  or  tannic  acid  mordant  before  immersion  in  the  silk  solution. 
It  should  afterward  be  calendered  and  polished  in  order  to  obtain  a  glossy 
appearance. 

20.  Statistical. — The  production  of  artificial  silk  of  different  varieties 
in  the  United  States  for  the  year  1921  was  about  20,000,000  lbs.  The 
total  annual  production  of  artificial  silk  in  the  entire  world  for  1914  was 
only  26,000,000  lbs.,  so  it  may  be  seen  that  this  industry  is  expanding  very 
rapidly.^  The  great  bulk  of  the  American  production  went  into  domestic 
consimiption,  and  besides  an  appreciable  amount  was  imported  (nearly 
4,000,000  lbs.).  The  field  for  artificial  silk  is  continually  growing  and 
is  by  no  means  exhausted  as  yet.  It  must  not  be  considered  simply 
as  a  substitute  or  competitor  for  real  silk,  but  the  artificial  fiber 
has  a  distinct  field  of  usefulness  for  itself.  It  is  adapted  to  the  manu- 
facture of  a  wide  variety  of  apparel  and  ornamental  fabrics  and  in  this 
connection  should  stand  on  its  own  basis  as  a  fiber. 

'  The  following  table  shows  the  estimated  amounts  of  the  different  varieties  of 
artificial  sUks  produced  in  the  world  in  the  year  1908 : 

Pounds. 

Collodion  silk 4,125,000 

Cuprate  silk 3,080,000 

Viscose  silk 1,089,000 

Total 8,294,000 

At  the  present  time  the  relative  order  of  these  varieties  is  reversed,  the  amount 
of  viscose  silk  produced  being  overwhelmingly  greater  than  the  others. 


732  ARTIFICIAL  SILKS 

There  are  a  number  of  companies  manufacturing  artificial  silk  in  the 
United  States,  of  which  the  following  are  the  more  important :  The  Amer- 
ican Viscose  Company  with  plants  at  Marcus  Hook,  Lewistown,  and 
Roanoke;  the  combined  plants  have  a  capacity  of  about  28,000,000  lbs. 
per  year.  The  Du  Pont  Fibersilk  Co.,  with  a  plant  at  Buffalo,  also 
making  viscose  silk  with  a  capacity  of  1,500,000  lbs.  per  year.  The 
Tubize  Ai-tificial  Silk  Co.  of  America,  with  a  plant  at  Hopewell  making 
pyroxylin  silk  with  a  capacity  of  about  4,500,000  lbs.  per  year.  The 
Industrial  Fiber  Co.,  of  Cleveland,  making  cuprate  silk  with  a  capacity 
of  1,000,000  lbs.  per  year.  The  Lustron  Company  of  Boston,  making 
acetate  silk.  The  American  Cellulose  and  Chemical  Company  with  a 
plant  at  Cumberland,  making  acetate  silk  with  a  capacity  of  3,000,000  lbs. 
per  year.  Most  of  the  artificial  silk  spun  is  of  150  denier  size,  though  the 
last-named  company  is  equipped  to  spun  as  fine  as  45  denier.  The 
Tubize  Company  spins  from  110  to  180  denier  silk.^ 

Ai'tificial  silk  has  supplemented  rather  than  directly  competed  with 
natural  silk,  though  in  certain  lines  of  fabrics,  such  as  cheap  hosiery 
and  underw^ear  and  sweaters  and  the  like,  it  may  be  said  to  be  a  substitute 
for  silk.  The  price  relations  of  the  two  fibers  are  somewhat  interesting. 
Unbleached  viscose  silk  yarn,  Grade  A,  150  denier,  in  1913  sold  for  $1.80 
per  pound  and  in  October,  1921,  for  S2.75  per  pound.  Raw  silk,  Shinsiu 
No.  1  in  1913  sold  for  $3.47  per  pound  and  in  1921  for  $6.05  per  pound. 

1  The  following  table  of  Exports  of  Artificial  SiUc  Hosiery  from  the  United  States 
is  interesting  from  the  statistical  point  of  view: 

1918.  1919.  1920.  1921. 

Coimtry.  (Dozen  Pairs.) 

Belgium 13,113  9,991  13,714 

Denmark 1,000  129,879  66,193  16,352 

France 150  3,231  20,734  5,376 

Italy 15,675  2,300  16,015  14,611 

Spain 4,755  7,700  4,225 

Switzerland 8,470  3,876  3,409 

United  Ivingdom 231,500  459,552  577,885  294,341 

Canada 69,650  57,905  62,114  12,034 

Mexico 6,819  8,368  7,755  11,528 

Cuba 16,459  33,829  31,320  29,914 

Argentina 28,829  136,549  90,686  68,610 

Brazil 438  1,789  1,888  1,466 

Chile 2,792  7,949  5,136  8,098 

Uruguay 1,500  11,834  18,013  12,582 

British  East  Indies 837  1,814  3,841  9,822 

Australia 69,510  255,810  75,616  44,742 

New  Zealand 14,469  51.474  10,678  7,731 

British  South  Africa 18,426  61,773  13,908  9,629 

Other  countries 22,883  67,217  82,905  90,610 

Total 500,937    1,317,611     1,106,254       658,794 


STATISTICAL 


733 


The  manufacture  of  artificial  silk  has  also  the  opportunity  of  developing 
other  products  with  the  same  equipment  and  raw  material.  By  increasing 
the  size  of  the  aperture  through  which  the  cellulose  solution  is  forced, 
artificial  hair,  of  value  in  the  manufactm^e  of  hats,  upholstery  materials  and 
fancy  goods,  may  be  produced.  By  changing  the  shape  of  the  aperture  to 
a  horizontal  slit,  it  is  possible  to  make  artificial  straw,  or  by  widening  the 
slit  further,  strips  of  artificial  leather  or  cloth,  films,  ribbons,  or  thin 
transparent  sheets  such  as  are  used  in  facing  envelopes  and  wrapping 
candies.  A  method  has  been  de\'ised  in  which  net  and  simple  forms 
of  lace  are  produced  in  one  operation,  by  passing  the  solution  into  engraved 
lines  on  a  revolving  cyhnder,  from  which  the  finished  product  is  con- 
tinuously peeled  as  it  issues  from  the  fixing  bath.  Further  progress  in 
this  direction  may  be  confidently  expected  as  the  possibihties  of  cellulose 
are  as  yet  far  from  exhausted.^ 

At  no  time  during  the  past  decade,  nor  even  at  present,  has  the  world 
supply  of  artificial  silk  been  equal  to  the  demand.  The  follo^-ing  table 
{Commerce  Reports)  shows  the  imports  of  artificial  silk  yarns  into  the 
United  States  for  the  past  ten  years:- 


Year. 

Pounds. 

Value. 

Year. 

Pounds. 

Value. 

1912 
1913 
1914 
1915 
1916 

1,457,544 
1,942.177 
2,759,306 
2,780,063 
2,041,193 

§1,757,989 
2,385,350 
3,461,039 
3,302,599 
2,924,458 

1917 
1918 
1919 
1920 
1921 

.506,613 

293,421 

298,122 

2,251,927 

2,613,024 

$1,262,580 

741,822 

825,117 

8,690,952 

^  Artificial  silk  is  now  used  extensively  in  the  manufacture  of  trimmings,  braids, 
embroidery  flosses,  hat  ornaments,  gloves,  hosiery,  sweaters  and  knit-fabrics,  necktie 
fabrics,  and  in  combination  with  wool,  silk  or  cotton  for  various  dress   goods  and 
fancy  fabrics,  velvets,  satins,  draperies,  up  hoist  erj'  and  carpet  goods. 
^  It  is  also  interesting  to  note  the  sources  of  these  importations: 

1914. 
Country. 

Austria-Himgarj' 47,396 

Belgium 584,181 

France 140,220 

Germany 488,978 

Italy 59,808 

Netherlands 4,867 

Switzerland 157,675 

United  Ivingdom 1,274,134 

Canada 2,047 

Japan 

Other  countries 


1919. 

1920. 

1921. 

(In  Poimds.) 

5,557 

22,418 

508,698 

479,239 

2.455 

105.476 

227,459 

31,391 

44.119 

89,708 

203,446 

515,227 

294,362 

163,467 

121,913 

664,418 

563,739 

114.687 

358,235 

525,388 

5,676 

21,729 

21,672 

22,000 

42,526 

4.635 

3,361 

72 

Total 2,759,306       298,122    2,251,927    2,613,024 


734 


ARTIFICIAL  SILKS 


The  domestic  production  of  artificial  silk  in  this  country  is  given  as 
follows  {War  Industries  Board  Bulletin  No.  25,  1919). 


Year. 

Pounds. 

Year. 

Pounds. 

1913 
1914 
1915 

1,566,000 
2,445,000 
4,111,000 

1916 
1917 
1918 

4,744,000 
6,687,000 
5,828,000 

The  domestic  production  of  artificial  silk  as  given  by  another  authority 
is  as  follows: 


Year. 

Pounds. 

Year. 

Pounds. 

1922 
1921 
1920 
1919 
1918 

24,406,000 

15,000,000 

8,000,000 

8,000,000 

5,828,000 

1917 
1916 
1915 
1914 
1913 

6,687,000 
4,744,000 
4,111,000 
2,445,000 
1,566,000 

The  world's  production  of  artificial  silk  is  given  as  follows: 

In  Pounds. 

United  States 23,500,000 

England 15,340,000 

Germany 12,584,000 

Belgium 6,292,000 

France 6,292,000 

Holland 2,516,800 

Switzerland 1,887,600 

Austria 1,573,000 

Hungary 1,887,600 

Poland 943,800 

Czecho-Slovakia 629,200 

Italy 6,292,000 

Total 79,738,000 

The  importations  of  artificial  silk  into  the  United  States  for 

1913     were       2,400,000  pounds 
1922     were     23,500,000  pounds 

For  comparison  the  importations  of  raw  silk  for 

1913     were     26,050,000  pounds 
1922     were     48,150,000  pounds 


STATISTICAL  735 

In  England  the  output  of  artificial  silk  (1919)  was  about  10  tons  per 
day,  in  Germany  5  tons,  and  in  France  4  tons  daily. 

The  Tubize  factory  in  Belgium  had  a  pre-war  capacity  of  about  10,000 
pounds  per  day.  Since  the  war  it  has  rapidly  been  reconstructed  and  is 
now  operating  at  even  a  higher  capacity.  This  plant  uses  the  Chardonnet 
process,  but  is  understood  to  be  changing  over  to  the  viscose  method. 
Artificial  silk  is  now  manufactured  in  England,  Switzerland,  Belgium, 
Poland,  Germany,  Russia,  Italy  and  Japan,  and  the  United  States. 


CHAPTER  XXII 
LINEN 

1.  The  Flax  Plant. — Linen  is  the  fiber  obtained  from  the  flax  plant, 
botanically  known  as  Linuin  usitatissimum.  Botanists  recognise  upward 
of  one  hundred  species  of  the  flax  plant,  but,  of  all  these,  the  only  one 
possessing  industrial  importance  and  the  only  one  readily  cultivated  is 
the  Linum  usitatissimum,  which  has  a  blue  flower.  The  North  American 
Indians  have  long  used  the  fiber  of  L.  lewisii,  which  differs  from  the 
ordinary  cultivated  flax  in  having  three  stems  growing  from  a  perennial 
root.  The  most  ancient  species  of  flax  brought  under  cultivation  is 
thought  to  be  L.  angustifolium;  the  Swiss  lake-dwellers  are  said  to  have 
grown  it,  as  also  the  ancient  inhabitants  of  northern  Italy.  The  flax 
cultivated  in  the  eastern  countries,  in  Assyria  and  Egypt,  appears  to  have 
been  the  common  variety  L.  usitatissimum.  Greek  or  spring  flax, 
L.  crepitans,  is  a  small  plant  somewhat  cultivated  in  Russia  and  Austria. 
Two  other  varieties  are  also  cultivated  to  some  extent  in  Austria,  perennial 
flax  (L.  perenne)  and  purging  flax  (L.  catharticum).  The  flax  employed 
by  the  North  American  Indians  for  making  fish  nets  was  also  a  perennial 
plant,  L.  lewisii. 

The  fiber  is  prepared  from  the  bast  of  the  plant  by  a  process  called 
retting,  which  has  for  its  purpose  the  separation  of  the  fibrous  cellulose 
from  the  woody  tissue  and  other  plant  membranes.  Historically  linen 
appears  to  have  been  the  earliest  vegetable  fiber  employed  industrially, 
having  been  used  at  a  much  earlier  date  than  cotton.  Egyptian  linen 
fabrics  (mummy-cloths)  have  been  found  which  are  probably  over  4500 
years  old.  Flax  is  mentioned  in  the  book  of  Exodus  as  one  of  the  products 
of  Egypt  in  the  time  of  the  Pharaohs.  Solomon  purchased  linen  yarn  in 
Egypt  and  Herodotus  speaks  of  the  great  flax  trade  of  Egypt.  Numerous 
pictorial  representations  of  the  cultivation  and  preparation  of  flax  are 
sculptured  on  the  walls  and  tombs  of  Thebes,  showing  the  varieties  of 
flax  in  the  red  and  white  flower,  the  manner  of  pulling,  retting,  etc.,  as 
practiced  when  Jacob  dwelt  in  the  land  of  Goshen.^ 

'By  some  good  authorities  grave  doubt  is  expressed  that  the  so-called  "linen" 
mentioned  in  the  Bible  was  derived  from  the  flax  plant  at  all,  it  being  pointed  out 
that  flax  is  indigenous  to  the  temperate  climates  of  Northern  Europe  but  cannot  be 
grown  in  the  hot  climates  included  in  Bible  lands.  It  is  claimed  that  the  mimimy 
cloth  of  the  ancient  Egyptians  was  made  from  ramie  fiber  rather  than  from  flax. 

736 


THE   FLAX   PLANT  737 

Though  grown  more  or  less  in  every  country,  at  present  the  cultivation 
of  flax  is  principally  carried  on  in  France,  Ireland,  Belgium,  Holland, 
Russia,  United  States,  and  Canada.^ 

Onl}^  in  the  vicinity  of  Yale,  Michigan,  at  Northfield  and  Heron  Lake, 
Minnesota,  and  at  Salem  and  Scio,  Oregon,  is  flax  cultivated  in  America 
for  the  production  of  spinning  fiber.  In  all  these  localities  the  seed  is 
saved,  and  it  is  doubtful  if  the  industry  would  yield  sufficient  profits  from 
the  production  of  the  fiber  alone  to  warrant  its  continuance  under  present 
conditions.-  New  England  formerly  cultivated  flax  on  the  extensive 
scale  for  the  fiber,  but  this  was  rapidly  replaced  by  the  introduction  of 
cotton  manufacturing,  which  together  with  the  exhaustion  of  the  soil, 
led  to  the  abandonment  of  this  industry  in  that  part  of  the  United  States 
early  in  the  nineteenth  century. 

The  Department  of  Agriculture  gives  the  following  marks  of  the  com- 
mercial grades  of  flax  imported  into  the  United  States : 

From  Russia:  Russian  flax  is  known  either  as  Slanetz  (dew-retted)  or 
Motchenetz  (water-retted);  ungraded  fiber  is  called  Siretz.  The  latter 
comes  chiefl}^  from  St.  Petersburg,  and  is  known  under  the  names  of 
Bejedsk,  Krasnoholm,  Troer,  Kashin,  Gospodsky,  Nerechta,  Wologda, 
Jaraslav,  Graesowetz,  and  Kosroma;  all  these  varieties  are  slanetz. 
Pochochon,  Ouglitz,  Rjeff,  Jaropol,  and  Stepurin  are  motchenetz.  From 
Archangel  are  brought  slanetz  varieties  known  as  First  Crown,  Second 
Crown,  Third  Crown,  Fourth  Crown,  First  Zabrack,  and  Second  Zabrack. 
From  Riga  are  obtained  motchenetz  varieties  graded  from  the  standard 
mark  K  through  HK,  PK,  HPK,  SPK,  HSPK,  ZK,  GZK,  and  HZK. 

From  Holland:  Dutch  flax  is  graded  by  the  marks  tV'  "v'  VI,  VII,  VIII, 

IX. 

From  Belgium:    Flemish  flax  (or  blue  flax)  includes  Bruges,  Thisselt, 

Ghent,  Lokeren,  and  St.  Nicholas,  and  is  graded  as  y^,  ^,  -^,  VI,  VII,  VIII, 

IX.     Courtrai  flax  is  graded  as  ^,  j^,  ^y,  jy,  -y,  y,  VI. 

'  Japan  is  rapidly  attaining  prominence  in  flax  growing.  It  is  estimated  that 
83,464  acres  of  flax  were  grown  in  the  Northern  Island  during  1920.  This  is  the 
largest  crop  ever  grown;  imfortimately,  the  quahty  was  poor  owing  to  heavy  rains. 
Japan  now  ranks  fourth  among  the  flax-producing  countries,  but  the  j'ield  per  acre 
is  less  than  half  that  of  Ireland — 200  lbs.  as  compared  with  450  lbs.  This  is  largely 
due  to  inferior  seed  and  careless  farming.  The  Agricultural  Department  of  Hokkaido 
Government  is  dealing  with  the  question  of  seed  selection,  and  the  farmers  have 
formed  local  guilds  and  propose  to  set  up  a  Central  Association  in  Sapporo  to  distribute 
seed,  advance  loans,  and  undertake  the  distribution  of  the  fiber.  Each  local  guild 
is  eventually  to  run  a  scutching  mill  of  its  own.  There  are  already  65  scutching  mills 
in  Japan. 

-  Yearbook,  Dept.  Agric,  1903. 


738 


LINEN 


Furnes  and  Bergues  flax  is  graded  A,  B,  C,  D.  Walloon  flax  is  graded 
II,  III,  IV.  Zealand  flax  is  graded  IX,  VIII,  VII,  VI.  Friesland  flax  is 
graded  D,  E,  Ex,  F,  Fx,  Fxx,  G,  Gx,  Gxx,  Gxxx. 

From  France:  French  flax  is  known  by  the  districts  of  Wavrin,  Flines, 
Douai,  Hazebrouck,  Picardy,  and  Harnes. 

From  Ireland:  Irish  flax  comes  as  scutched  and  mill  scutched,  and  is 
known  by  the  names  of  the  counties  in  which  it  is  raised. 

C        P 
A     B 


Fig.  292. — Cross-section  of  Flax-straw.  A,  Layer  of  cuticular  cells;  B,  intermediate 
layer  of  cortical  parenchym ;  C,  bast  fibers  in  groups,  being  the  fla.x  fibers  proper 
(note  secondary  thickening  of  cell-walls);  D,  cambium  layer;  E,  woody  tissue. 
(Cross  and  Bevan.) 


From  Canada:  This  flax  has  no  standard  of  marks  or  qualities. 

The  flax  plant  is  annual  in  growth  and  rather  delicate  in  structure. 
It  grows  to  about  40  inches  in  height;  the  stem  is  slender,  branching  only 
slightly  at  the  top,  and  bears  naked,  lanceolate,  alternate  leaves.  The 
flower  is  mostly  sky-blue,  though  sometimes  white;  the  seed-capsules  are 
five-lobed  and  globular,  and  of  the  size  of  peas.     The  bast  tissue,  which  is 


THE  FLAX  PLANT 


739 


used  for  the  fiber,  is  situated  between  the  bark  and  the  underlying  woody 
tissue  (Fig.  292). 

Flax  fiber  is  from  12  to  36  ins.  in  length,  silver  gray  when  dew-retted, 
yellowish  white  when  water-retted,  capable  of  fine  subdivision,  soft  and 
flexible,  and  is  the  strongest  of  the  fine  commercial  bast  fibers.  It  is  used 
for  making  linen  sewing  thread,  shoe  thread,  bookbinders'  thread,  fishing- 
lines,  seine  twine,  the  better  grades  of  wrapping  twine,  and  knit  underwear, 
and  for  weaving  into  handkerchiefs, 
towelling,  table  linen,  collars  and  cuffs, 
short  bosoms,  and  dress  goods.  The 
finer  grades  of  linen  damasks  are  im- 
ported, as  the  weaving  of  these  goods  is 
slow  work,  and  requires  a  kind  of  labor 
not  commonly  found  in  this  country. 

Generally,  about  two  bushels  of 
flaxseed  are  sown  per  acre,  and  the 
>ield  in  finished  fiber  is  from  600  to  800 
lbs.,  having  a  market  price  of  about  12 
cents  per  pound  (1913).  The  yield  of 
seed  is  from  8  to  10  bushels  of  52  lbs. 
each.  The  growing  of  a  flax  crop  is  very 
exhausting  to  the  soil;  potash  and  phos- 
phoric acid  are  the  chief  ingredients  that 
the  soil  requires  to  produce  a  good  crop 
of  flax  for  either  fiber  or  seed.  It  requires 
from  400  to  600  lbs.  of  mineral  or  phosphate 
fertilisers  per  acre,  besides  barn-yard  and 
other  manures,  to  keep  the  soil  in  con- 
dition, and  then  only  two  to  three  crops 
can  be  raised  in  succession. 

The  flax  plant  is  subject  to  a  num- 
ber of  diseases  which  at  times  may 
become  epidemic  and  cause  great  in- 
jury to  the  crop.  The  Agricultural 
Department  of  Ireland  recently  (1920) 
made   a    detailed   investigation  of  these 

diseases.  They  are  distinguished  as  follows:  seedling-blight  due  to  a 
parasitic  fungus;  this  disease  spreads  rapidly  in  wet  weather  but  is  checked 
by  dry  atmosphere  and  soil;  it  can  be  somewhat  controlled  by  suitable 
disinfection,  but  a  perfect  method  for  this  has  not  yet  been  dis- 
covered. Browning  is  also  due  to  a  fungus;  the  upper  parts  of  the  plant 
become  brown  and  brittle  and  yield  a  short  fiber;  it  may  be  controlled 
by  properly  disinfecting  the  seed.     Rust  and  firing  are  due  to  the  attacks 


Fig.  293.— The  Ancient  Flax  Plant. 

{Linum  anguslifolium .) 
(After  Bulletin  U.  S.  Dept.  Agric.) 


740 


LINEN 


of  a  parasitic  fungus  belonging  to  the  group  of  rusts.  Firing  spoils  the 
appearance  of  the  fiber  and  weakens  it  in  spots.  Yellowi?ig  is  probably- 
due  to  a  potash  starvation  of  the  soil  and  is  cured  by  applying  proper 
fertilizer.  Another  disease  known  as  dead  stalks  is  also  due  to  a  fungus. 
Dodder,  which  is  a  parasitic  twining  plant  that  lives  on  the  flax,  is  also  a 
pest.  Another  enemy  is  the  flax  flea  beetle,  whose  depredations  are  some- 
times very  serious. 

The  following  table  shows  the  production  and  consumption  in  the 
world's  flax  trade  for  1913: 


Country. 


Russia 

Austria-Hungary 

France 

Belgium 

United  Kingdom 

Italy 

Sweden 

Germany 

United  States .  . . 
Total 


Production. 


Available 

for 
Consump- 
tion . 


(In  Gross  Tons.) 


837,697 
39,159 
21,624 
17,606 
12,652 
2,5.59 
218 


931,515 


522 

53,586 

111,111 

192,946 

99,122 

2,715 

2,613 

92,536 

11,634 


268,138 

5,162 

84,447 

72,345 

5,244 

1 

42,818 


570,081 

87,583 

48,288 

138,207 

106,530 

5,273 

2,831 

49,718 

11,634 


The  total  production  of  flax,  therefore,  prior  to  the  Great  War  was  approx- 
imately 2,000,000,000  lbs.,  of  which  by  far  the  greater  part  was  produced 
in  Russia.  Since  the  Russia  Revolution,  however,  the  production  of  flax 
has  greatly  decreased  in  that  country,  and  at  the  present  time  (1923) 
does  not  amount  to  more  than  about  25  percent  of  the  pre-war  figure. 

Besides  being  cultivated  for  its  fiber,  the  flax  plant  is  also  grown  for 
its  seed,  which  yields  the  valuable  oil  known  as  linseed.  It  possesses  good 
drying  qualities,  and  hence  is  extensively  used  for  the  preparation  of  paints 
and  varnishes.  The  best  seed-flax  is  grown  in  tropical  and  subtropical 
countries,  whereas  the  best  fiber-flax  is  grown  in  more  northern  climates. 
The  seed  obtained  from  the  latter  variety,  though  utilised  as  a  by-product, 
produces  only  an  inferior  grade  of  oil.  The  oil-cake  left  after  expressing 
the  oil  from  the  seed  is  an  excellent  cattle-food  and  is  largely  used  for  this 
purpose. 

There  are  large  quantities  of  flax  grown  in  America,  chiefly  in  the 
Northwestern  States;  but  it  is  grown  almost  entirely  for  seed,  the  plant 
being  allowed  to  ripen  fully  before  harvesting,  and  the  flax  straw  being 


THE   RETTING  OF  FLAX  741 

burned  to  get  rid  of  it.  The  United  States,  in  fact,  furnishes  about  one- 
fourth  of  the  world's  supply  of  linseed  oil.  In  1900-1901  the  yield  of  oil 
was  about  40,000,000  gallons.  The  Argentine  Republic  is  the  greatest 
flax-growing  country  in  the  world ;  but  the  plant,  in  this  case,  too,  is  grown 
only  for  the  seed  and  the  straw  is  burned.  The  yield  of  oil  from  this 
country  is  about  55,000,000  gallons,  or  about  one-third  of  the  world's 
supply.  Russia  has  a  large  acreage  devoted  to  the  cultivation  of  flax- 
seed ;  the  fiber,  however,  is  of  minor  importance,  being  woody  and  subject 
to  great  waste  in  preparation.  In  India  flax  is  also  mainly  grown  for  the 
seed. 

2.  The  Retting  of  Flax. — The  flax  plant,  after  attaining  its  proper 
growth,  is  either  cut  down  or  pulled  up  by  its  roots,  and  subjected  to  a 
process  technically  known  as  rippling,  the  plants  being  drawn  through  a 
machine  consisting  of  upright  forks  which  remove  the  seeds  and  leaves. 
The  remaining  stalks  are  then  tied  in  bundles  and  placed  in  stagnant 
water,  where  they  are  allowed  to  remain  for  a  number  of  days.  Active 
fermentation  soon  starts,  resulting  in  the  decomposition  of  the  woody  tis- 
sues enclosing  the  cellulose  fibers.  When  the  process  has  gone  sufficiently 
far,  the  bundles  of  fermented  stalks  are  removed  and  passed  through  a 
number  of  mechanical  operations,  whereby  the  decomposed  tissues  are 
removed  and  the  linen  fibers  are  isolated  in  a  purified  condition.  This 
method  of  retting  with  stagnant  water  is  known  as  "  pool-retting."  As 
the  fermentation  causes  the  evolution  of  considerable  gas,  in  order  to  keep 
the  bundles  of  stalks  submerged,  they  are  loaded  with  stones  or  boards. 
The  time  of  steeping  in  the  water  varies  with  circumstances  from  five  to 
ten  days.  Another  method  of  retting  is  to  steep  in  running  water.  The 
famous  Courtrai  flax  of  Belgium  is  retted  in  this  manner  in  the  river  Lys. 
The  flax-straw,  after  pulling,  is  placed  in  crates  and  submerged  in  the 
water  of  this  stream  for  a  period  of  fom*  to  fifteen  days,  depending  on  the 
temperature  and  other  conditions.  Courtrai  flax  is  of  a  creamy  color, 
whereas  pool-retting  flax  has  a  rather  dark  bluish  brown  color.  The 
excellent  qualities  of  the  Courtrai  flax  are  said  to  be  due  to  the  action  of  the 
soft,  slowly  running,  almost  sluggish  waters  of  the  river  Lys,  and  to  the 
peculiar  ferment  existing  therein.  Another  method  employed  for  obtaining 
the  fiber  from  flax  is  known  as  dew-retting,  as  the  flax-straw  is  spread  out 
in  a  field  and  exposed  for  a  couple  of  weeks  to  the  action  of  the  dew  and 
the  sun.  Dew-retting,  however,  gives  the  most  uneven  and  least  valuable 
product  of  the  three  methods  employed,  and  the  fiber  is  rather  dark 
in  color.  There  have  also  been  several  chemical  methods  proposed  for 
retting  flax,  such  as  heating  with  water  under  pressure,  boiling  with 
solutions  of  oxalic  acid,  soda  ash,  caustic  soda,  etc.  None  of  these  however, 
have  proved  of  any  industrial  value,  and  the  older  natural  methods  are 
still  adhered  to.     Additions  of  various  chemicals  to  the  retting  waters 


742 


LINEN 


have  at  times  proved  of  value,  hydrochloric  or  sulfuric  acid  sometimes 
being  used  to  advantage. 

Dodge  gives  the  following  notes  relative  to  the  retting  of  flax:  "  For 
dew-retting  a  moist  meadow  is  the  proper  place,  the  fiber  being  spread 
over  the  ground  in  straight  rows  at  the  rate  of  a  ton  to  an  acre.  If  laid 
about  the  1st  of  October  and  the  weather  is  good,  a  couple  of  weeks  will 
suffice  for  the  proper  separation  of  the  fiber  and  woody  matter.  For 
pool-retting  the  softest  water  gives  the  best  results,  and  where  a  natural 
pool  is  not  available,  such  as  the  '  bog-holes  '  in  Ireland,  '  steep  pools  ' 
will  have  to  be  built.  A  pool  30  ft.  long,  10  ft.  wide,  and  4  ft.  deep  will 
suffice  for  an  acre  of  flax.  Spring  water  should  be  avoided,  or,  if  used, 
the  pool  should  be  filled  some  weeks  before  the  flax  is  ready  for  it,  in  order 


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^^^^^^^^Hft 

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Fig.  294— Flax  Breaker. 


to  soften  the  water.  It  should  be  kept  free  from  all  mineral  and  vegetable 
impurities.  The  sheaves  are  packed  loosely  in  the  pool.  Fermentation 
is  shown  by  the  turbidity  of  the  water  and  by  bubbles  of  gas.  If  possible, 
the  thick  scmn  which  forms  on  the  surface  should  be  removed  by  allowing 
a  slight  stream  of  water  to  flow  over  the  pool.  The  fiber  sinks  when 
decomposition  has  been  carried  to  the  proper  point,  though  this  is  not 
always  a  sure  indication  that  it  is  just  right  to  take  out.  In  Holland 
the  plan  is  to  take  a  number  of  stalks  of  average  fineness,  which  are  broken 
in  two  places  a  few  inches  apart.  If  the  woody  poi-tion  or  core  pulls  out 
easily,  leaving  the  fiber  intact,  it  is  ready  to  come  out.  The  operation 
usually  requires  from  five  to  ten  days." 

Schenck's  method  of  retting  is  to  steep  in  warm  water,  a  constant 
temperature  of  35°  C.  being  maintained.  It  is  said  that  the  fermentation 
may  be  completed  by  this  method  in  fifty  to  sixty  hours,  and  gives  a  larger 


THE  RETTING   OF  FLAX  743 

jneld  and  a  better  product  than  the  natural  processes  of  retting.  In 
steam-retting,  the  bundles  of  flax  straw  are  placed  in  iron  cylinders  and 
heated  with  live  steam  or  hot  water  under  pressure,  but  the  process  does 
not  appear  to  be  successful.  Loppens  and  de  Swarte  ^  introduced  a  method 
in  which  the  flax  straw  is  placed  upright  in  a  tank  through  which  passes 
an  upward  current  of  water.  The  dissolved  matters  form  a  heavy  solu- 
tion which  falls  to  the  bottom.- 

The  intercellular  substance  holding  the  flax  fibers  together  consists 
mostly  of  calcium  pectate,  and  the  real  object  of  retting  is  to  render  this 
substance  soluble,  so  that  it  may  be  removed  bj^  the  after-processes  of 
treatment.  Winogradsky  has  succeeded  in  isolating  the  particular 
organism  that  is  the  active  agent  in  the  pectin  fermentation.^  It  is  an 
anaerobic  bacillus  which  readily  ferments  pectin  matters,  but  has  no  action 
on  cellulose. 

Beijerinck  and  van  Delden  ascribe  the  bacterial  action  in  flax  retting 
to  a  fermentation  of  the  pectose  first  into  pectin,  and  then  into  sugars, 
through  the  action  of  an  enzyme,  pectinase,  secreted  by  the  bacteria. 
According  to  Behrens  the  active  agents  in  dew-retting  are  mould  fungi. 

The  water-retting  of  flax  is  described  by  Stormer  as  a  biological  proc- 
ess induced  bj^  the  action  of  definite  organisms,  the  chief  of  which  is  an 
anaerobic  Plectridium,  which  in  the  absence  of  air  ferments  the  pectin 
substances  of  the  cellular  material  uniting  the  parenchjanous  tissues, 
and  thus  causes  a  loosening  of  the  bast  fibers.^  The  exclusion  of  oxj'gen, 
which  is  necessary  that  the  fermentation  may  be  set  up,  is  brought  about 
by  numerous  oxygen-consuming  bacteria  and  fungi.  The  products 
formed  by  the  fermentation  of  the  pectin  substances  are  hydrogen  and 
carbon  dioxide  and  organic  acids,  especially  acetic  and  butyric  and  small 
quantities  of  valeric  and  lactic  acids.  The  injurious  action  of  the  acids 
produced,  especially  butyric  acid,  may  be  considerably  diminished  by 
adding  alkali  or  lime  to  the  retting  liquid.     It  is  also  advantageous  to 

»  Bnl.  Pal.  14,781  of  1895. 

-  According  to  Crochet  {Ger.  Pat.  146,956)  the  flax  is  boiled  in  a  bath  containing 
lime  water,  caustic  soda  and  crystal  soda  (the  latter  seems  to  be  incompatible  as  it 
would  precipitate  the  lime),  then  treated  with  a  hot  soap  bath.  Bonney  and  Pritchard 
(Ger.  Pat.  199,042)  use  sodium  borate  and  soap  solution,  while  Summers  {Ger.  Pat. 
197,659)  uses  only  a  solution  of  potash.  Probably  the  best  chemical  retting  is  done 
by  the  old  Bauer  process  (Ger.  Pats.  68,807  and  80,023)  in  which  the  flax  is  treated 
for  one  hour  at  212°  F.  with  a  |  percent  solution  of  sulfuric  acid,  and  afterward  with 
a  hot  dilute  solution  of  caustic  soda  (see  Chem.  Zeit.,  1906,  p.  983). 

^  There  seems  to  be  some  confusion  as  to  the  exact  species  of  this  organism.  Wino- 
gradsky designates  it  as  the  Bacillus  amylobacter,  while  Beijerinck  and  van  Delden 
call  it  Granidohacter  pectinovornm . 

^  Prof.  Rossi-Portici  (see  Oesterr.  Wollen.  hid.,  1908,  pp.  641  and  1409)  has  prepared  in 
a  successful  commercial  manner  the  particular  ferment  for  flax  retting;  it  is  called 
Bacillus  comesii  and  is  said  to  produce  complete  retting  in  about  three  days. 


744  LINEN 

inoculate  the  liquid  at  the  beginning  of  the  retting  with  pure  cultures  of 
the  anaerobic  Plectridium. 

By  adding  salts  promoting  the  growth  of  the  bacillus  to  the  water 
employed  in  retting,  it  has  been  found  possible  to  reduce  the  time  of  retting 
veiy  considerably. 

An  interesting  method  of  retting  flax  is  described  by  Jean,  Doumcr 
and  Romain  ^  as  follows :  The  retting  takes  place  in  a  hermetically  closed 
vessel  with  the  addition  of  water  heated  to  40°  to  50°  C.  and  the  applica- 
tion of  an  air  pump.  The  flax  is  placed  in  a  vessel  between  two  wire 
gauze  bottoms.  By  means  of  the  pump  all  of  the  air  is  exhausted  and  the 
flax  is  treated  in  the  water  for  several  days.  The  retting  is  said  to  be 
complete  in  five  to  six  days.  It  would  seem,  however,  that  this  method 
requires  a  large  amount  of  apparatus  for  a  small  production  of  fiber. 

Krais  -  recommends  the  use  of  a  1  percent  solution  of  sodium  bicar- 
bonate for  retting.  The  addition  of  0.5  to  1  percent  of  sodium  sulfite 
to  the  retting  liquor  is  also  recommended  as  it  gives  a  lighter  color  product. 
The  disagreeable  odor  of  the  retting  liquor  may  be  improved  by  adding 
Bome  dextrose  along  with  the  sodium  bicarbonate. 

3.  Preparation  of  Flax  in  Belgium. — According  to  Carter  the  method 
of  preparing  flax  fiber  in  Belgium  is  as  follows:  The  flax  straw,  before  it 
becomes  quite  ripe,  is  pulled  up  by  the  roots  in  handfuls  and  spread  on 
the  ground  in  rows,  the  handfuls  laid  with  tops  and  roots  alternating, 
which  prevents  the  seed  bolls  from  becoming  entangled  when  the  handfuls 
are  again  lifted.  The  laborious  operation  of  the  hand-pulling  of  flax 
is  likely  to  be  pretty  generally  superseded  in  the  near  future  by  machine 
pulling.  The  straw  is  stacked  as  soon  after  pulling  as  possible,  the  hand- 
fuls resting  against  each  other;  the  root  ends  will  spread  out,  and  the 
tops  join,  like  the  letter  A.  In  six  or  eight  days  the  straw  is  dry  enough 
to  be  tied  into  sheaves  like  corn  sheaves.  It  is  then  ricked  and  allowed 
to  stand  in  the  field  until  the  seed  is  dry  enough  for  stacking.  Under  the 
Courtrai  system  the  seed  is  taken  off  during  the  winter  and  the  straw 
restacked  or  kept  under  cover  until  the  spring,  when  it  is  sometimes 
retted.  It  is  generally  considered  better,  however,  that  the  flax  straw 
be  kept  for  at  least  a  year,  and  it  is  sometimes  kept  for  two  years  before 
steeping.  The  seeders  bind  the  straw  into  parallel  bundles  about  12  ins. 
in  diameter,  which  for  steeping  are  packed  either  horizontally  or  vertically 
in  large  wooden  crates  or  ballons,  lined  with  straw.  The  upright  position 
is  usually  adopted,  as  it  is  said  to  be  more  favorable  to  the  production 
of  light-colored  fiber,  as  no  sediment  or  deposit  can  rest  upon  it  at  any 
stage  of  fermentation.  Straw  and  boards  are  afterwards  placed  on  top, 
and  the  crate  thus  charged  slid  into  the  river  and  anchored  in  the  stream, 

'  Lcipziger  Monatschrift  Texiilindustrie,  1892 
'^Zeil.  angew.  Chem.,  1920,  p.  102. 


PREPARATION   OF  FLAX   IN   BELGIUM  745 

and  weighted  with  stones  so  that  it  is  submerged  a  few  inches  below  the 
surface.  In  a  few  days  fermentation  begins,  and  as  it  proceeds  additional 
stones  must  be  added  from  time  to  time  in  order  to  prevent  the  rising  of 
the  crates  through  the  evolution  of  gas.  As  a  rule,  after  steeping  for  a 
few  days,  the  flax  is  removed  from  the  crates  and  set  up  in  hollow  sheaves 
to  dry,  the  advantage  of  the  interruption  of  the  retting  process  at  this 
stage  being  that  exposure  to  the  sun  and  air  kills  the  microbes  of  putre- 
faction which  have  developed,  so  that  the  strength  of  the  fiber  remains 
unimpaired.  When  dry,  or  later,  it  is  repacked  in  the  crates  and  again 
steeped  until  retting  is  complete — seven  to  twelve  days,  according  to  the 
temperature,  quahty  of  flax,  etc.  The  duration  of  steeping  is,  say,  about 
seven  days  in  August,  ten  in  May,  and  twelve  in  October,  when  the  tem- 
peratm'e  of  the  water  is  much  lower.  Fine  thin  stems  require  a  longer 
time  to  ret  than  do  stouter  stems.  The  end  of  the  process  is  accurately 
determined  by  occasionally  examining  the  appearance  of  the  stems  and 
applying  certain  tests.  The  bundles  of  straw  should  feel  soft,  and  the 
stems  be  covered  with  a  greenish  slime,  easily  removed  by  passing  them 
between  the  finger  and  thumb.  When  bent  over  the  forefinger,  the 
central  woody  portion  should  spring  up  readily  from  its  fibrous  envelope. 
If  a  portion  of  the  fiber  is  separated  from  the  stem  and  suddenly 
stretched,  it  should  draw  asunder  with  a  dull  and  not  a  sharp 
sound. 

When  retting  is  complete,  the  flax  straw  is  carefully  removed  from  the 
crates  and  again  set  up  in  sheaves  to  dry,  this  time  in  the  shape  of  a 
hollow  cone.  The  retted  and  dried  straw  is  then  stored  in  barns  and 
sheds  until  winter,  when  scutching,  or  cleaning  the  fiber  from  the  woody 
part  of  the  stem,  takes  place.  The  scutch  mill  machinery  consists  first 
of  all  of  a  breaker  or  crushing  rollers,  a  series  of  pairs  of  fluted  rollers 
which  crush  the  straw  and  break  up  the  "  boon  "  into  small  pieces,  which 
in  the  case  of  Courtrai  and  other  flax  which  has  been  skillfully  retted,  are 
easily  separated  from  the  fiber  by  the  strokes  of  a  beater.  The  best  flax 
rollers  are  in  sets  of  5,  6,  or  8  pairs,  the  rollers  being  about  8  ins.  in  diameter 
and  having  from  16  to  24  flutes,  ^  in.  to  1  in.  deep. 

The  broken-up  woody  matter  is  then  knocked  out  of  the  fiber,  as  the 
scutchers  hold  it  in  handfuls  in  a  notch  in  an  upright  plank  or  stock,  by 
revolving  beaters  or  handles  of  wood,  which,  fixed  upon  a  cast-iron  rim 
keyed  upon  a  shaft  making  about  175  revolutions  per  minute,  make 
about  2100  strokes  per  minute,  there  being  12  blades  to  the  round  in  a 
Belgian  scutch  mill.  The  effective  diameter  of  the  circle  being  4  ft.  6  ins., 
their  speed  is  nearly  2500  ft.  per  minute. 

An  acre  of  fairly  good  flax  is  estimated  to  weigh  ''  on  foot,"  or  when 
freshly  pulled,  about  5  tons.  In  drying  it  loses  about  55  percent  of  its 
weight.     Rippling  or  seeding  reduces  its  weight  by  another  25  percent, 


746 


LINEN 


5    3    1 


steeping  by  another  25  percent;  and  if  the  yield  of  fiber  in  scutching  be 
taken  at  20  percent,  the  yield  of  fiber  is  only  about  51  percent  of  the 
weight  of  the  green  straw. 

Of  the  various  systems  of  retting,  that  effected  in  the  slow  current  of 
running  water  undoubtedly  gives  the  best  results  as  regards  color  and 
quality  of  the  fiber  produced.  Of  recent  years  Continental  experts  have 
studied  the  question  of  producing  the  same  effects  by  other  means,  and 
a  most  practical  system  introduced  by  Messrs.  Legrand  and  Vansteinkiste 
has  been  adopted  by  a  number  of  flax  factors,  both 
on  the  Lys  and  far  from  it,  and  a  number  of  retteries 
built. 

4.  Impurities  in  Raw  Flax. — The  substances  classi- 
fied in  a  general  way  as  "  pectin  matters  "  form  the 
intercellular  matter  between  the  elemental  cells  of 
the  bast  fibers,  and  serve  the  purpose  of  a  cementing 
medium  to  hold  the  small  elements  of  the  fiber  to- 
gether. Their  character  is  that  of  a  resinous  gum. 
By  certain  investigators  this  resinous  matter  has  been 
given  the  name  pectose.  It  is  hardly  likely,  however, 
that  this  substance  consists  of  a  single  chemical  com- 
pound, but  it  is  more  probably  a  mixture  of  several 
chemical  individuals.  By  heating  with  dilute  acid, 
pectose  is  converted  into  a  series  of  products  which 
have  received  considerable  attention  from  botanical 
chemists;  the  products  include  pectin,  para-pectin, 
Fig.  295. — Diagram  7neta-pectin,  pectosic  acid,  pectic  acid,  parapectic  acid, 
of  Flax-straw.  (1)  meta-pectic  acid,  etc.  Pectin  and  especially  para-  and 
Marrow;  (2)  woody  metapectin  are  soluble  in  water,  whereas  pectic  acid  is 

,       '     /A\    u      +   not.     Therefore,  if  it  is  desirable  to  separate  the  de- 
layer;    '4)     bast  '  .  .      _  ^ 

fiber-  (5)  rind  or  ments  of  a  vegetable  tissue,  it  is  necessary  to  stop 
bark.  (After  Witt.)  the  action  of  the  retting  agents  before  the  formation 
of  pectic  acid.  In  the  case  of  the  preparation  of  linen, 
however,  it  appears  to  be  necessary  not  to  dissolve  out  all  the  pectose 
derivatives  from  the  fiber,  but  to  allow  of  the  formation  of  some  pectic 
acid,  as  this  makes  the  surface  of  the  fiber  more  brilliant  and  leaves  it 
stronger  and  more  elastic. 

It  has  been  claimed  that  fatty  acids  exert  a  solvent  action  on  the  resin- 
ous and  pectin  matters  present  in  vegetable  fibers,  and  a  method  for  the 
decortication  of  flax  and  other  bast  fibers  has  been  devised  as  follows: 
The  raw  fibers  are  impregnated  with  boihng  soap  solutions,  after  which 
ammonium  chloride  is  added,  which  liberates  the  fatty  acids.  After 
several  hours'  treatment  these  dissolve  all  gummy  and  resinous  matters; 
the  fibers  are  then  treated  with  weak  caustic  alkali,  after  which  they  are 


IMPURITIES  IN  RAW  FLAX  747 

washed  and  dried  when  they  should  be  thoroughly  disintegrated.  Good 
results  are  said  to  be  obtained  b}-  this  method. 

The  flax  stalks,  after  being  deprived  of  their  leaves  and  seeds  by 
rippling,  are  known  as  flax-straw.  The  latter  in  the  air-dry  condition 
contains  from  73  to  80  percent  of  wood,  marrow,  and  bark,  and  20  to  27 
percent  of  bast.  The  general  structure  of  flax-straw,  and  of  bast  stalks 
in  general,  is  shown  in  the  schematic  drawing  (Fig.  295). 

According  to  Prof.  Hodge  (of  Belfast),  the  proportions  among  the 
constituent  parts  of  the  flax  plant  are  as  follows: 

Pounds. 

Dried  flax  plants 7770 

BoUs 1946 

Seed 910 

Raw  fiber  stalks 5824 

Loss  in  steeping 1456 

Retted  stalks 4368 

Finished  fiber 702 

Hence,  the  weight  of  the  fiber  was  equal  to  about  9  percent  of  the  dried 
flax  stalk  with  the  seed-bolls,  or  to  12  percent  of  the  bolted  straw,  or  to 
over  16  percent  of  the  retted  straw. 

According  to  Schenck  (American  process),  the  following  proportions 
were  obtained. 

Tons. 

Dried  flax  straw 100 

Bolls 33 

Loss  in  steeping 27 . 5 

Separated  in  scutching 32 .  13 

Finished  fiber 5.9 

Low  and  pluckings 1 .  47 

In  the  carding  and  spinning  of  flax  there  is  a  considerable  amount  of 
waste  produced  consisting  of  short  fibers  var^'ing  in  length  from  |  to  3 
ins.  Considerable  endeavor  has  been  expended  in  efforts  to  utiHse  this 
waste  flax  for  the  spinning  of  low  grades,  but  not  with  very  good  success. 
The  chief  difficulty  in  the  spinning  of  waste  flax  is  due  to  the  fact  that 
the  fibers  are  stiff  and  lack  coherence,  which  causes  them  to  separate  in 
the  spun  j^arn  and  thus  leave  the  latter  without  any  strength.  A  recent 
German  process  for  the  utilisation  of  waste  flax  for  spinning  attempts 
to  give  the  short  fibers  a  greater  softness  and  flexibility  together  ^\'ith 
sufficient  curl  to  make  the  fibers  more  coherent  w^hen  spun  into  a  yarn. 
The  flax  waste  is  first  beaten  or  heckled  in  order  to  remove  shives,  and 
is  then  boiled  for  one  hour  in  a  5  percent  solution  of  caustic  soda.  This 
treatment  is  said  to  cause  a  curling  of  the  fibers.  The  material  is  then 
washed  and  placed  in  a  second  bath  consisting  of  500  parts  sal  soda,  250 
parts  soft  soap,   1000  parts  cream  tartar,   150  parts  painter's  glue,  250 


748 


LINEN 


parts  olive  oil,   100   parts   acetic  acid,  dissolved  in  220  parts  of  water, 
and  heated  to  about  115°  F.     This  solution  forms  a  milky  acid  emulsion 


Fig.  296. — Flax  Fibers.     (X400.)     a,  o',  Cross-sections;  fe,  longitudinal  views;  c,  ends. 

(Cross  and  Bevan.) 


in  which  the  fiber  is  left  for  one  hour, 
placed  in  a  bath  containing  lactic  acid. 


It  is  then  hydroextracted  and 
It  is  claimed  that  by  carding  the 
material  thus  treated  a  woolly 
soft  fleece  is  obtained,  which 
may  readily  be  spun  into 
yarn. 

6.  Microscopy  of  Linen 
Fiber. — The  linen  fiber  as  it 
is  obtained  from  the  plant 
and  as  it  appears  in  trade  is  in 
the  form  of  filaments,  the  length 
of  which  varies  considerably 
with  the  manner  and  care 
employed  in  decorticating,  and 
may  be  from  a  few  inches  to 
several  feet.  These  filaments 
'^  are   composed   structurally  of 

Fig.  297.— Flax  Fiber.  (X300.)  ^,  Longitudinal  small  elements  or  ceUs,  con- 
view,  showing  jointed  structure  and  tracing  of  sisting  of  practically  pure  cell- 
lumen;  fi,  cross-sections.  uloge.      They    are    uniformly 

thick,  and  average  12  to  25 
microns  in  diameter  and  25  to  30  mm.  in  length.  Their  structure  is 
rather  regular,  being  cylindrical  in  shape,  though  somewhat  polygonal 
in  cross-section.     A  peculiarity  in  the  appearance  of  the  cells  is  the  occur- 


MICROSCOPY  OF  LINEN   FIBER 


749 


rence  of  faintly  marked  "  dislocations  "  or  so-called  "  nodes  "  extending 
transversely  and  often  in  the  form  of  an  "X."  ^  These  nodes  may  be 
made  more  apparent  by  staining  with  Methyl  Violet  or  chlor-iodide  of 
zinc  solution.  The  cell-wall  is  quite  uniform  in  thickness,  and  the  lumen 
or  internal  canal  is  very  narrow,  and  often  is  but  faintly  apparent  as  a 
dark  line.  The  cross-section  of  the  linen  fiber  shows  no  yellow  circum- 
ferential stain  when  treated  with  sulfuric  acid,  though  the  lumen  shows 
up  as  a  yellow  spot.  Wiesner  gives  the  following  dimensions  of  several 
varieties  of  flax  filaments: 


Kind  of  Flax. 


Egyptian 

Westphalian .  .  .  . 
Belgian  Courtrai 

Austrian 

Prussian 


Mean  Length  of  the 

Purified  Flax  Fiber, 

Mm. 


960 
750 
370 
410 

280 


Mean  Breadth, 
Mm. 


0.255 
0.114 
0.105 
0 .  202 
0.119 


Good  flax  should  average  20  ins.  in  length  and  be  free  from  fibers  less 
than  12  ins.  in  length. 

Dodge  gives  the  following  dimensions  for  the  elements  of  the  flax  fiber: 
Length,  0.157  to  2.598  ins.;  mean,  about  1  in.;  diameter,  0.006  to  0.00148 
in.;    mean,  0.001  in. 

Hanausek  ^  gives   a  microscopical   method   of  distinguishing   between 
linen  and  tow  yarns,  as  follows: 

1.  Linen  yarn  consists  of  fiber  cells  which  mostly  have  narrow  lumens 
and  pointed  ends,  and  is  mostly  free  from  other  tissues  of  the  stem. 

2.  Tow  yarn  consists  of  fiber  cells  with  both  narrow  and  broad  lumens, 
and  always  contains  epidermal  cells. 

Herzog  also  points  out  that  fibers  which  he  designates  as  "  unripe  " 
occur  in  tow.  These  fibers  are  from  the  upper  part  of  the  flax  stems  and 
have  broad  lumens  with  abundant  remains  of  protoplasmic  contents. 

The  bast-cells  of  the  flax  fiber  may  be  isolated  by  treatment  with  a  dilute 
chromic  acid  solution.     They  are  cylindrical  in  form  and  taper  to  a  point 

^  Hohnel  {Ueber  den  Einfluss  des  Kindendruckes  auf  der  Beschaffenteil  der  Baslfasern, 
Jahrbuch,  Wins.  BoL,  vol.  15,  p.  311)  considers  that  these  dislocations  or  cross-folds 
are  of  physiological  origin  resulting  from  inequalities  in  the  radial  pressure  of  the 
tissues  in  the  plant.  Schwendener  (Ueber  die  "Verschiebungen"  der  Bastfasern.  Ber. 
Deutsch.  Bot.  Gesell.,  vol.  12,  p.  239),  on  the  other  hand,  considers  them  as  resulting 
from  artificial  influences  during  the  processes  of  preparation,  as  fibers  obtained  by 
simple  retting  in  water  show  almost  a  complete  absence  of  such  distortions 

-  Microscopy  of  Technical  Productfi,  p.  77. 


750 


LINEN 


at  each  end.  At  the  middle  they  measure  12  to  26  microns,  with  an 
average  of  about  15  microns.^  The  length  varies  from  4  to  66  mm., 
with  an  average  of  about  25  mm.     The  ratio  of  the  length  of  the  cell 


Fig.  298. — Flax  Fiber  Showing  Nodes  Stained  with  Chlor-iodide  of  Zinc.     (Herzog.) 

to  its  breadth  is  about  1200.  Under  the  microscope  the  surface  of  the 
cell  appears  smooth  or  marked  longitudinally,  with  frequent  transverse 
fissure  lines  and  jointed  structures.     On  treatment  with  chlor-iodide  of  zinc 


Fig.  299.— Flax  Fiber.     (X300.)     Stained  with  Methyl  Violet.     J,  Joint-Hke  forma- 
tions;  F,  fissure-like  markings.     (Micrograph  by  author.) 

the  latter  are  colored  much  darker  than  the  rest  of  the  cell  and  are  thus 
rendered  more  apparent.  The  lumen  appears  in  the  center  of  the  cell  as  a 
narrow  yellow  line,  and  it  is  usually  completely  filled  with  protoplasm. 
With  iodine  and  sulfuric  acid  linen  gives  a  blue  color,  which,  however, 
^  According  to  Vetillard,  15  to  37  microns,  with  an  average  of  22  microns. 


CHEMICAL  AND   PHYSICAL  PROPERTIES  751 

develops  less  quickly  than  with  cotton;  with  tincture  of  madder  an  orange 
color  is  produced,  while  fuchsine  (followed  with  ammonia)  gives  a  per- 
manent rose  color  in  contradistinction  to  cotton.  These  tests,  however,  are 
only  applicable  to  unbleached  linen,  for  the  cellulose  of  bleached  linen  shows 
Uttle  or  no  chemical  difference  from  that  of  cotton.  In  cross-section  the 
cells  of  flax  are  polygonal,  with  rounded  edges,  show  a  small  lumen,  and  a 
relatively  thick  cell-wall.  In  these  respects  they  are  very  similar  to  hemp, 
but  may  be  distinguished  from  the  latter,  however,  in  that  they  do  not 
aggregate  in  thick  bundles,  but  are  more  or  less  isolated  from  each  other, 
so  that  the  cross-section  frequently  shows  but  one  cell,  and  seldom  more 
than  three  or  four. 

Other  differences  from  hemp  exhibited  by  the  Hnen  fiber  are:  (a)  the 
cross-section  does  not  show  an  external  yellow  layer  of  lignin  when  treated 
with  iodine  and  sulfuric  acid;  (h)  it  gives  reactions  for  pure  cellulose  only, 
that  is,  iodine  and  sulfuric  acid  color  the  fiber  a  pure  blue,  and  aniline 
sulfate  gives  no  color,  though  at  times  there  are  shreds  of  parenchymous 
tissue  present  which  are  colored  3^ellow  by  this  latter  reagent  and  appear 
to  be  lignified;  (c)  the  lumen  of  the  hemp  fiber  is  seldom  filled  with 
yellowish  protoplasm  like  that  of  the  Hnen  fiber;  (d)  the  linen  fibers 
end  in  sharp  points,  whereas  those  of  hemp  do  not. 

6.  Chemical  and  Physical  Properties. — The  flax  fiber  appears  to  consist 
of  pure  cellulose  and  shows  no  signs  at  all  of  being  lignified.  Though  the 
flax  fiber  is  generally  considered  as  non-lignified,  Hohnel  ^  is  of  the  opinion 
that  very  short  sections  with  lignified  cross-waUs  occur  between  long 
sections  with  walls  of  pure  ceUulose.  Herzog  determined  the  Kgnin  in 
fibers  from  different  parts  of  the  plant  by  the  methyl  oxide  method,  and 
found  that  fibers  from  the  root  contained  3.8  percent,  from  the  middle  of 
the  stem  2.36  percent  and  from  the  tip  of  the  stem  1.64  percent  of  lignin. 
By  bleaching  the  lignin  is  entirely  removed. 

In  order  to  isolate  pure  flax  cellulose,  Cross  and  Bevan  have  recom- 
mended the  following  procedure:  The  non-cellulosic  constituents  of  flax 
are  pectic  compounds  which  are  soluble  in  boiling  alkaline  solutions. 
The  proportion  of  such  constituents  varies  from  14  to  33  percent  in  dif- 
ferent varieties  of  flax.  They  may  be  completely  extracted  by  first  boiling 
the  fiber  in  a  dilute  solution  of  caustic  soda  (1  to  2  percent);  the  residue 
will  consist  of  flax  cellulose,  with  smaU  remnants  of  woody  and  cuticular 
tissue,  together  with  some  of  the  oils  and  waxes  associated  with  the  latter. 
By  treatment  with  a  w^ak  solution  of  chloride  of  lime,  the  woody  tissue  is 
decomposed,  and  is  then  removed  by  again  boihng  in  dilute  alkali.  The 
remaining  cellulose  is  then  further  purified  from  residual  fatty  and  waxy 
matters  by  boiling  with  alcohol  and  finally  with  ether-alcohol  mixture. 

>  Zur  Mikroskojne  der  Hanf  und  Flachsfaser,  Zeitschr.  Nahr.  Unlers.  Hyg.  Warenk., 
1892,  p.  30. 


752 


LINEN 


Flax  cellulose  prepared  in  this  manner  appears  to  be  chemically  indistin- 
guishable from  cotton  cellulose. 

Linen    becomes    strongly    swollen    by    treatment    with    Schweitzer's 

reagent  (see  Figs.  301  and 
302),  but,  unlike  cotton, 
it  does  not  completely 
dissolve  therein.  In  swell- 
ing the  fiber  blisters  con- 
siderably, but  not  in  as 
regular  a  manner  as  cot- 
ton. The  inner  layers  of 
the  cell  withstand  the 
action  of  the  reagent  the 
longest  and  remain  float- 
ing in  the  liquid,  like  the 
cuticle  of  cotton.  Par- 
enchymous  and  intercel- 
lular matter  adhering 
to  the  fiber  also  re- 
mains undissolved  in  the 
reagent. 

According  to  Hanau- 
sek  ^  by  cautiously  treat- 
ing flax  fibers  with  iodine 
and  weak  sulfuric  acid  three  layers  may  be  distinguished:  first,  an  outer 
dark-blue  layer  becoming  liquid  in  the  reagent;  second,  a  longitudinally 
striated  light-blue  tube;  and  third,  a  narrow  yellow  tube  with  yellow 
contents.  If  strong  sul- 
furic acid  is  used  the 
whole  cell-wall  changes 
to  a  blue  swollen  mass, 
and  only  the  inner  tube 
containing  protoplasmic 
remains  persists  for  any 
considerable  time.  In 
cuprammonia  the  cellu- 
lose wall  goes  into  solu- 
tion with  the  formation 

of  a  blue  color  and  bladder-like  swellings,  while  the  inner  tube  remains  as 
a  sinuous,  and  in  parts,  almost  curled  thread. 

The  color  of  the  best  varieties  of  flax  is  a  pale  yellowish  white.     Flax 
retted  by  means  of  stagnant  water,  or  by  dew,  is  a  steel  gray,  and  Egyptian 
'  Microscopy  of  Technical  Products,  p.  74. 


Fig.  300.- 


-Flax  Fibers  Treated  with  Chlor-iodide  of 
Zinc.     (Herzog.) 


Fig.  301.— Cell  of  Flax  Fiber  Treated  with  Schweitzer's 
Reagent.  (X400.)  Showing  insoluble  cuticle  of  inner 
canal.     (Wiesner.) 


CHEMICAL  AND  PHYSICAL  PROPERTIES  753 

flax  is  a  pearl  gray.  The  pale  yellow  color  of  flax  is  due  to  a  natural  pig- 
ment, but  the  other  color  arises  from  the  decomposition  of  the  intercellular 
matter,  which  is  left  as  a  stain  on  the  fiber.  Flax  that  has  been  imper- 
fectly retted  shows  a  greenish  color.  The  natural  color  of  hnen  is  readily 
bleached  by  solutions  of  chloride  of  lime  in  a  manner  similar  to  the  bleach- 
ing of  cotton.  But  the  linen  fiber  suffers  considerable  deterioration 
thereby.  There  are  four  grades  of  linen-bleaching — quarter,  half,  three- 
quarters,  and  full  bleach.  The  whiter  the  fiber  is  bleached  the  weaker  it 
becomes.  In  determining  the  size  (or  number)  of  bleached  linen  yarns, 
the  loss  in  bleaching  is  fixed  at  20  percent  for  full,  18  percent  for  three- 
quarters,  and  15  percent  for  one-half  bleach. 

The  luster  of  linen  is  quite  pronounced  and  almost  silky  in  appearance ; 
flax  that  is  overretted  is  dull  in  appearance.  Egyptian  flax  is  also  dull,  due 
to  the  cells  being  coated  with  residual  intercellular  matter. 


/ 


Fig.  302. — Flax  Fiber  Swollen  with  Schweitzer's  Reagent.     (Herzog.) 

The  flax  fiber  is  much  stronger  than  that  of  cotton,  though  overretted 
flax  is  brittle  and  weak.  According  to  Spon,  samples  of  flax  fiber  exposed 
for  two  hours  to  steam  at  2  atmospheres,  boiled  in  water  for  three  hours, 
and  again  steamed  for  four  hours,  lost  only  3.5  percent  in  weight,  while 
Manila  hemp  under  these  conditions  lost  6.07,  hemp  6.18  to  8.44,  and 
jute  21.39  percent. 

As  flax  is  a  better  conductor  of  heat  than  cotton,  Hnen  fabrics  always 
feel  colder  to  the  touch  than  those  made  from  cotton. 

Cottonised  flax  was  a  name  given  to  a  product  made  by  disintegrating 
flax  by  chemical  means  into  a  fine  cotton-like  material,  by  a  process 
proposed  by  Claussen  in  1851.  The  flax  was  first  treated  with  a  dilute 
solution  of  caustic  soda,  then  impregnated  with  a  solution  of  soda  ash, 
and  immersed  in  a  dilute  solution  of  sulfuric  acid,  the  fibers  being  dis- 
integrated by  the  liberation  of  the  carbon  dioxide  gas.  Fabrics  woven 
from  yarns  of  this  material,  however,  were  found  to  be  deficient  in  strength, 


754 


LINEN 


and  the  process  never  met  with  commercial  success.  It  has  been  sug- 
gested, however,  to  employ  it  for  the  preparation  of  absorbent  lint  for 
surgical  purposes,  it  being  claimed  that  the  lint  prepared  fi'om  this  material 
is  more  absorbent  and  antiseptic  than  that  from  cotton  waste. ^ 

According  to  Rasser^  cottonising  may  be  applied  to  any  fiber  having 
a  woolly  feel,  such  as  jute,  hemp,  flax,  typha,  and  the  like,  but  chiefly  to 
flax  and  hemp  tows  and  spinning  wastes,  as  well  as  to  fibers  derived  from 
the  pulling  of  rags,  twine,  and  cloth  wastes,  recovered  hemp  and  flax 
fibers,  jute  wastes,  and  lastly,  flax  and  hemp  grown  for  seed.  A  distinc- 
tion must  be  made  between  technical  and  purely  chemical  cottonising. 
In  technical  cottonising  the  wastes  or  fibers  are  passed  through  specially 
constructed  willows  and  then  submitted  to  a  crimping  process.  A  real 
solution  into  the  ultimate  fibers  does  not  occur,  and  only  coarse  yarns 


Fig.  303. — Linen  Fibers  under  Polarised  Light.     (Herzog.) 


may  be  spun  from  this  material,  which  owing  to  single  projecting  hairs 
are  not  so  smooth  as  the  chemically  treated  fibers.  In  the  latter  case  the 
fibers  are  isolated  into  their  ultimate  filaments  and  therefore  cohere  more 
effectively  to  one  another  when  spun  either  by  themselves,  or  as  more 

1  By  the  cottonising  process,  short  fibers  are  obtained  either  by  mechanical  or 
chemical  means.  By  bacterial  or  chemical  means,  especially  with  intensive  action, 
high  yields  of  tow  are  obtained,  which  can  no  longer  be  used  as  the  raw  material  for 
spinning.  Fifty  years  ago  Clausseu  introduced  the  use  of  flax  wool,  which  was  spun 
with  cotton  or  wool,  but  this  outlet  for  short  fibers  was  not  a  success  owing  to  the 
difficulty  of  spinning  in  machines  built  for  the  longer  cotton  fiber.  During  the  war, 
one  firm  used  flax,  hemp  and  jute  residues  as  well  as  nettle  fibers  for  coarse  cloths 
and  also  for  more  valuable  fabrics.  .Jute  residues  were  used  in  France  before  the  war 
for  making  artificial  worsted.  The  question  has  arisen  again  owing  to  the  high  cost  of 
cotton.  So  far,  no  great  advance  has  been  made  owing  to  the  necessity  for  special 
machinery,  new  methods  of  working  and  practical  experience.  It  is  suggested  that 
German  hemp,  normally  of  less  value,  short  flax,  and  tangled  flax  straw  might  be 
utilised.     The  problem  is  also  of  interest  to  India,  Canada  and  the  Argentine. 

2  Monat)}chrift  Textilindustrie. 


CHEMICAL  COMPOSITION   OF   LINEN 


755 


usual,  with  other  better  grade  fibers.  In  the  chemical  process  of  cotton- 
ising,  caustic  soda  and  chlorine  are  employed,  also  Turkey-red  oils  and 
soaps,  and  oxidising  substances.  Hemp  is  more  easily  cottonised  than 
flax.  In  order  to  make  the  cottonised  fiber  more  suitable  for  spinning 
it  is  recommended  to  treat  the  fiber  with  strong  cold  caustic  soda  solution 
and  then  wash  with  water. 

7.  Chemical  Composition  of  Linen. — The  following  analyses  show  the 
composition  of  two  typical  specimens  of  flax  (H.  MuUer) : 


I. 

Percent. 

II. 

Percent. 

Water  (hygroscopic) 

8.65 
3.65 
2.39 
82.57 
0.70 
2.74 

10  70 

Aqueous  extract 

Fat  and  wax 

6.02 
2  37 

Cellulose 

Ash  (mineral  matter) 

71.50 
1  32 

Intercellular  matter 

9  41 

According  to  Wiesner,  the  ash  of  the  Hnen  fiber  amounts  to  from  1.18 
to  5.93  percent,  and  shows  no  evidence  of  crystals. 

The  flax  fiber  contains  a  certain  wax-Hke  substance,  varj'ing  in  amount 
from  0.5  to  2  percent.  It  may  be  extracted  from  the  fiber  by  means  of 
benzene  or  ether.  The  color  of  the  wax  varies  with  that  of  the  flax  from 
which  it  is  obtained.  It  has  a  rather  unpleasant  odor,  resembling  flax 
itself.  Its  melting-point  is  61.5°  C,  and  its  specific  gra^-ity  at  60°  F.  is 
0.9083.  According  to  Hoffmeister,  this  wax  consists  of  81.32  percent 
of  unsaponifiable  waxj^  matter  and  18.68  percent  of  saponifiable  oil.  Of 
the  latter,  54.49  percent  is  free  fatty  acid.  The  waxy  matter  has  a  melt- 
ing-point of  68°  C,  and  apparent^  is  a  mixture  of  several  bodies.  The 
principal  one  resembles  ceresin,  and  there  are  also  present  cerj'l  alcohol 
and  phj'losterin.  The  saponifiable  matter  appears  to  contain  small 
quantities  of  soluble  fatty  acids,  like  caproic,  stearic,  palmitic,  oleic, 
linolic,  Hnolenic,  and  isolinolenic. 

Highly  purified  flax  appears  to  approximate  very  closely  to  both  the 
composition  and  chemical  properties  of  cotton.  The  ordinary  flax  fiber 
of  trade  may  be  said  to  contain  about  5  percent  less  of  cellulose  than 
cotton,  there  being  about  that  much  more  impurity  present  in  the  form 
of  intercellular  matter  and  pectin  bodies.  Linen,  however,  appears  to 
be  free  from  woody  or  lignified  tissue,  as  it  gives  none  of  the  reactions 
for  these.  Hohnel  has  shown,  however,  there  are  short  spaces  on  the  fiber 
which  are  strongly  lignified.     Most  of  this  lignin  is  removed  by  bleaching. 

The  hnen  fiber  sweUs  up  greatly  when  treated  with  an  ammoniacal 


756 


LINEN 


solution  of  copper  oxide,  but,  unlike  cotton,  it  does  not  exhibit  the  pecuhar 
sausage-shaped  appearance,  nor  does  it  dissolve  completely.  The 
hydroscopic  moisture  in  linen  is  about  the  same  as  in  cotton;  in  fact,  all 
vegetable  fibers  appear  to  contain  approximately  the  same  amount  (from 
6  to  8  percent). 

The  amount  of  "  regain  "  allowed  in  the  conditioning  of  linen  at 
Roubaix  is  from  10  to  12  percent.  Wiesner  gives  the  amount  of  hygro- 
scopic moisture  in  linen  as  5.7  to  7.22  percent.  The  Turin  Congress  fixed 
the  regain  for  linen  at  12  percent. 

Due  to  differences  in  structure,  linen  is  more  easily  disintegrated  than 
cotton,  and  consequently  does  not  withstand  the  action  of  boiling  alka- 
line solutions,  solutions 
of  bleaching  powder  or 
other  oxidising  agents, 
etc.,  as  well  as  cotton. 

Toward  mordants  and 
dyestuffs,  etc.,  linen  does 
not  react  as  readily  as 
cotton,  hence  its  manipu- 
lation in  dyeing  is  more 
difficult.  In  general,  how- 
ever, it  may  be  said  that 
the  dyeing  and  treatment 
of  linen  are  practical]}^ 
the  same  as  with  cotton. 
The  oil-wax  group  of 
constituents  in  the  flax 
fiber  plays  an  important 
part  in  the  spinning  of 
this  fiber,  and  the  failui-o 
of  many  of  the  artificial 
processes  of  retting  flax  may  be  attributed  to  the  fact  that  the  fiber  is 
left  with  a  deficiency  of  these  constituents.  In  the  breaking  down  of  the 
cuticular  celluloses,  whether  in  the  retting  or  in  the  bleaching  processes, 
these  waxes  and  oils  are  separated.  Their  complete  elimination  from  the 
cloth  necessitates  a  very  elaborate  treatment,  such  as  is  represented  by 
the  "  Belfast  Linen  Bleach." 

Hoffmeister  ^  has  shown  that  the  odor  and  suppleness  of  flax  are  due 
to  a  characteristic  wax  on  the  surface  of  the  fiber,  and  if  this  wax 
is  removed  by  suitable  solvents,  the  fiber  becomes  rough,  lusterless,  and 
brittle.     This  wax  is  insoluble  in  water,  has  a  specific  gravity  of  0.9083 


Fig.  304.— Flax  Fiber.     (Herzog.) 


1  Bcnchte,  1903,  p.  1047. 


LINEN   YARNS   AND   THEIR   PROPERTIES 


757 


(at  15°  C.)  and  melts  at  61.5°  C.  It  consists  chiefly  of  a  paraffin  resem- 
Ijling  ceresin  mixed  with  glycerides  of  several  fatty  acids.  It  also  contains 
phytosterol  and  ceryl  alcohol,  and  a  small  proportion  of  a  volatile  alde- 
hydic  substance.  The  so-called  "  flax-dust  "  in  linen  factories  was  found 
to  contain  10  percent  of  the  wax. 

8.  Linen  Yams  and  their  Properties. — Linen  j^arns  are  known  as 
hand-spun  or  machine-spun;  the  former  are  softer  and  smoother  and  more 
elastic,  but  uneven  and  less  rounded  in  form,  while  machine-spun  yarns 
are  stiff  and  rough,  but  of  uniform  thickness  and  perfectly  round.  Accord- 
ing to  the  method  of  spinning,  linen  yarns  are  also  known  as  dry-spun 
or  wet-spun;  the  former  have  greater  firmness,  but  higher  numbers  can 
be  obtained  by  wet-spinning.  Tow  yarns  arc  prepared  from  waste,  and 
are  characterised  by  numerous  knots  due  to  particles  of  shives.  In  the 
English  system,  the  counts  of  linen  yarns  are  expressed  by  the  number  of 
leas  in  a  pound,  each  lea  measuring  300  yds.  To  obtain  the  count  of  cotton 
yarn  corresponding  to  the  count  of  linen  yarn,  the  latter  number  is  divided 
by  2.8.  In  the  French  system,  the  count  of  linen  yarns  is  the  number  of 
hanks  of  1000  meters  contained  in  500  grams.  In  the  Austrian  system, 
the  count  indicates  the  number  of  hanks  to  10  English  pounds,  each  hank 
containing  3600  ells  (1  ell  =  30.68  ins.). 

Brun  ^  has  given  some  interesting  tests  showing  the  effect  of  the 
amount  of  moisture  on  the  strength  of  linen  sail  cloth.  It  would  seem 
that  as  the  amount  of  moisture  increases  the  strength  also  increases  in 
quite  a  remarkable  degree.     The  results  are  given  as  follows: 


MoLsture,  Percent. 

Strength  in  Kilos. 

Moisture,  Percent. 

Strength  in  Kilos. 

0.0 
2.2 
5.5 
9.0 

180 
190 
232 

288 

12.0 
15.0 
19.1 
35.0 

350 
402 
417 
425 

In  this  case  the  normal  amount  of  moisture  in  the  cloth  as  delivered 
was  9.0  percent.  These  figures  bear  out  the  well-known  fact  that  fabrics 
of  linen  (and  cotton  as  well)  are  much  harder  to  tear  when  wet  than  when 
dry. 

Higgins  -  gives  the  following  results  concerning  the  effect  of  various 
processes  on  the  properties  of  raw  linen  yarn : 


Chem.  Zeit.,  1893. 
^Jour.  Soc.  Chem.  Ind.,  1911,  p.  1295. 


758 


LINEN 

Loss  IN  Weight  During  Bleaching 


Brown  linen 

After  steeping 

After  lime  boiling . . 
After  lye  boiling. . . 
After  ohemicking.  . 
Fully  bleached .... 
Half-bleached  linen 


Weight, 
Grams. 

92.1 

88.7 

77 .  15 

70.93 

69.53 

67.52 


Loss, 
Percent. 


3.S 
16.2 
22.9 
24.5 
26.7 


Ash, 
Percent. 


1.28 

0.18 
0.08 
0.08 
0.07 
0.37 


Loss  IN  Tensile  Strength 


Brown  linen 

After  lime  and  lye  boils 

After  chemic 

Fully  bleached 


Warp, 

Filling, 

Grams. 

Grams. 

1050 

800 

890 

860 

860 

810 

780 

740 

9.  Absorbent  Flax. — Absorbent  flax  is  often  used  as  a  substitute  for 
absorbent  cotton.  iVs  is  well  known,  cotton  is  rendered  absorbent  by 
removing  the  gum  by  boiling  in  a  closed  kier.  Treated  in  this  way, 
cotton  is  used  for  bandaging  wounds.  The  objection  raised  to  absorbent 
cotton  is  that  it  retains  the  heat,  thus  promoting  fermentation  and  delaying 
the  healing  of  the  wound.  Absorbent  flax  is  a  better  conductor  of  heat 
and  thus  is  not  open  to  this  objection.  It  is  prepared  from  raw  flax  of 
which  50  to  60  lbs.  are  left  for  twenty-four  hours  in  a  bath  made  up  as 
follows:  1000  lbs.  water,  20  lbs.  caustic  soda,  5  lbs.  carbonate  of  soda, 
3^  lbs.  soap. 

This  bath  is  boiled  until  the  ingredients  are  thoroughly  dissolved. 
After  the  flax  is  removed  from  the  liquor  it  is  rinsed  in  running  water 
for  one-half  hour.  This  process  removes  the  gum  and  resinous  material 
from  the  fiber.  The  material  is  bleached  with  chloride  of  hme,  being 
immersed  for  twelve  to  fifteen  minutes  or  more  in  a  bath  at  120°  to  140°  F., 
made  up  as  follows:  1000  lbs.  water,  8  lbs.  chloride  of  lime. 

The  material  should  be  stirred  continuously  while  in  the  bleaching 
liquor  in  order  that  the  bleaching  may  be  uniform.  The  flax  is  then 
rinsed  in  running  water  for  one  hour.  These  preliminary  operations  of 
degumming  and  bleaching  are  carried  on  by  ordinary  methods. 


ABSORBENT  FLAX  759 

The  last  part  of  the  process  which  consists  in  rendering  the  flax  absorb- 
ent, is  the  subject  of  a  patent  ^  granted  to  Marin.  The  bleached  fibers 
are  immersed  for  ten  minutes  in  the  following  bath:  1000  lbs.  water, 
100  lbs.  bisulfite  of  soda. 

The  material  is  then  extracted  and  rinsed  in  running  water,  after  which 
it  is  immersed  for  fifteen  to  twenty  minutes  in  a  bath  at  104°  F.,  made  up 
as  follows:   1000  lbs.  water,  20  lbs.  sulfuric  acid. 

After  this  treatment  it  is  rinsed  in  running  water  and  treated  in  a  bath 
at  140°  F.,  made  up  as  follows:  1000  lbs.  water,  15  lbs.  oxalic  acid. 

This  last  treatment  lasts  for  about  thirty  minutes,  during  which  the 
material  is  frequently  agitated  in  order  to  make  the  treatment  uniform. 
After  rinsing  and  drying  the  flax  is  perfectly  absorbent,  silky,  and  lustrous. 

1  Ft.  Pat.  453,500,  AprU  4,  1912. 


CHAPTER  XXIII 
JUTE,  RAMIE,  AND  HEMP 

1.  The  Jute  Plant. — Jute  is  a  fiber  obtained  from  the  bast  of  various 
species  of  Corchorus,  growing  principally  in  India  and  the  East  Indian 
Islands.^  The  most  important  variety  is  Corchorus  capsularis  or  Jew's 
mallow,  which  is  grown  throughout  tropical  Asia  not  only  as  a  fiber  plant, 
but  also  as  a  vegetable.  Other  varieties  are  C.  olitorius,  C.  fuscus,  and 
C.  decemangulatus;  the  latter  two,  however,  yield  but  a  small  proportion 
of  the  jute  fiber  to  be  found  in  trade. 

The  commercial  fiber  known  as  Chinese  jute  is  not  a  variety  of  jute  at  all, 
but  is  derived  from  Abutilon  avicennce  or  Indian  mallow.  The  latter  grows 
extensively  as  a  weed  in  America."  The  bast  fiber  is  white  and  glossy,  and 
has  considerable  tensile  strength.  It  is  also  used  for  the  making  of  paper 
stock.  Chemically  it  appears  to  consist  of  bastose,  and  hence  resembles 
jute  in  its  behavior  toward  dyestuffs.  The  plant  produces  about  20  per- 
cent of  fiber,  but  is  of  doubtful  economic  value.  Another  somewhat  similar 
variety  is  the  Abutilon  incanum^  which  grows  in  Mexico;  it  is  said  that 
the  Indians  used  the  fiber  from  this  plant  for  making  hammocks,  ropes, 
and  nets,  which  are  so  durable  that  they  last  from  seven  to  ten  years  in 
constant  use.  There  are  also  several  East  Indian  species,  of  Abutilon, 
among  which  may  be  named  A.  indicum,  A.  graveolens,  A.  rmdicum,  and 
A.  polyandrum,  all  of  which  are  fiber  plants  suitable  chiefly  for  cordage; 
the  latter  yields  a  long  silky  fiber  resembling  hemp.  The  A.  periplocifo- 
liuni,  growing  in  tropical  America,  yields  a  very  good  bast  fiber,  quite  long, 

^  The  name  "jute"  is  derived  from  the  Sanskrit  "jhot,"  meaning  "to  be  entangled." 
The  Bengal  name  of  the  plant  is  "pat"  and  the  cloth  is  called  "tat  chotee."  In  the 
native  provinces  and  countries,  however,  the  names  for  jute  are  legion. 

2  Experimenters  have  stated  that  the  fiber  extracted  from  the  Indian  mallow  before 
the  plants  have  reached  their  full  maturity  is  fine  enough  to  be  used  in  the  making 
of  carpet  yarns  or  even  finer  fabrics.  It  takes  dyes  very  readily,  being  better  in  this 
respect  than  jute,  which  is  not  adaptable  to  cheap  bleaching  and  dyeing.  The  fiber 
was  once  classified  in  value  between  Italian  and  Manila  hemp,  but  according  to  Dodge 
it  will  not  grade  so  high,  coming  nearer  to  jute.  It  is  stated  that  one  acre  will  produce 
about  5  tons  of  the  stalks,  yielding  20  percent  of  fiber.  Many  experiments  have  been 
made  on  the  cultivation  of  Indian  mallow  in  the  United  States,  especially  in  the  Middle 
West  and  also  in  New  Jersey,  but  without  commercial  success.  The  fiber  is  separated 
from  the  stalks  by  retting  in  water  like  flax  of  hemp,  but  there  is  a  good  deal  of  gum 
present  which  increases  the  difficulty  of  obtaining  the  isolated  fiber. 

760 


THE   JUTE   PLANT 


761 


and  of  a  creamy  yellow  color.  The  native  name  is  Maholtine,  and  the 
fiber  may  be  easily  stripped  from  the  bark  with  no  other  preparation 
than  steeping  in  pools  of  water  for  five  to  eight  days.  Some  samples  of 
the  fiber  measure  10  to  12  feet  in  length.  A  lai'ge  crop  may  be  grown  per 
acre  but  there  does  not  seem  to  be  any  regular  cultivation  of  this  plant. 
It  is  estimated  that  5  tons  of  stripped  bark  may  be  obtained  per  acre 
and  this  yields  from  25  to  40  percent  of  cleaned  fiber.  Most  investigators 
of  this  fiber  seem  to  think  it  worthy  of  the  highest  consideration. 


A  B 

Fig.  305. — A,  Seed-vessels  of  Corchnrus  camularis;  B,  seed-vessels  of  Corchorus  olitorius. 

(After  Bulletin  V.  S.  Dept.  Agric.) 


The  jute  plant  grows  to  a  height  of  from  10  to  12  feet  and  its  fibrous 
layer  is  very  thick,  so  that  it  yields  from  two  to  five  times  as  much  fiber 
as  flax. 

The  Corchorus  capsularis  is  an  annual  plant,  growing  from  5  to  10  feet 
in  height,  with  a  cylindrical  stalk  as  thick  as  a  man's  finger,  and  seldom 
branching  near  the  top.  The  leaves,  which  are  of  light  green  color,  are 
from  4  to  5  ins.  long  by  1|  ins.  broad  toward  the  base,  but  tapering  upward 
into  a  long  sharp  point  with  edges  cut  into  saw-like  teeth,  the  two  teeth 
next  the  stalk  being  prolonged  into  thistle-like  points.  The  flowers  are 
small  and  of  a  yellowish  white  color,  coming  out  in  clusters  of  two  or  three 
tog:ether  opposite  the  leaves.     The  seed-pods  are  short  and  globular, 


762  JUTE,   RAMIE   AND   HEMP 

rough  and  wrinkled  (Fig.  305  a).  The  C.  olitorius  is  precisely  like  the 
former  in  general  appearance,  shape  of  leaves,  color  of  flower,  and  habits 
of  growth;  but  it  differs  entirely  in  the  formation  of  the  seed-pod,  which 
is  elongated,  almost  cylindrical,  and  of  the  thickness  of  a  quill  (Fig.  305  b). 

2.  Preparation  of  Fiber. — The  preparation  of  the  fiber  from  the  jute 
plant  is  a  rather  simple  operation.  The  plant  is  usually  cut  while  in 
bloom  and  the  stalks  are  freed  from  leaves,  seed-capsules,  etc.,  and  retted 
by  steeping  in  a  sluggish  stream  of  water.  After  a  few  days  the  bast 
becomes  disintegrated,  and  the  retted  stalks  are  pressed  and  scutched. 
The  fiber  so  obtained  is  remarkably  pure  and  free  from  adhering  woody 
fiber  and  other  tissue.  The  prepared  fiber  usually  has  a  length  of  from 
4  to  7  ft.,'  possesses  a  pale  yellowish  brown  color,  though  the  best  qualities 
are  pale  yellowish  white  or  silver  gray,  and  exhibits  considerable  luster 
and  tensile  strength.  The  ends  of  the  plant,  together  with  the  various 
short  waste  fibers,  appear  in  trade  under  the  name  of  "  jute  butts  "  or 
"  jute  cuttings,"  and  are  employed  as  a  raw  material  for  paper- 
manufacturing. 

Dodge  remarks  on  the  extraction  of  jute  that  machinery  has  not  been 
used  for  this  purpose  in  India,  the  process  being  to  ret  in  stagnant  water 
assisted  by  the  personal  labor  of  the  natives.  Such  a  method,  however, 
could  not  be  operated  in  America  or  even  in  Europe.  It  would  be  neces- 
sary to  use  machines  to  separate  the  fiber  from  the  stalk,  but  this  method 
alone  does  not  prepare  the  fiber  in  marketable  form,  and  the  decorticated 
ribbons  of  fiber  would  have  to  be  retted  to  remove  the  gums  and  woody 
matters  and  yield  a  fiber  capable  of  being  spun. 

According  to  Carter,  jute  is  probably  the  most  easily  decorticated 
of  any  of  the  bast  fibers.  After  being  cut  with  a  sickle  the  bundles  of 
stems  are  placed  in  tanks  or  pools  of  stagnant  water,  or  even  in  running 
water  if  more  convenient.  The  bundles  are  covered  with  straw  to  protect 
them  from  the  direct  rays  of  the  sun,  which  would  make  the  fiber  specky. 
Sods  are  used  to  keep  the  bundles  under  water,  but  this  practice  is  to  be 
condemned,  as  the  sods  discolor  the  fiber.  Logs  of  wood  should  be  used 
in  preference.  The  retting  process  usually  lasts  from  ten  to  twenty  days. 
During  this  time  fermentation  has  been  set  up  and  softens  the  tissue  in 
which  the  fiber  is  imbedded,  and  renders  the  gummy  matter  soluble  until 
the  fiber  comes  away  quite  readily  from  the  woody  portion  of  the  stem. 
The  stalks  are  examined  periodically  to  test  the  progress  of  the  retting 
operation,  and  when  it  is  found  that  the  fiber  peels  off  easily,  the  operation 
is  complete  and  the  bundles  are  withdrawn.  If  under-retted,  gum  remains 
and  sticks  the  fibers  together.  Over-retting  makes  the  fiber  weak  and 
dull  in  color.  The  water  used  has  a  considerable  effect  upon  the  quality 
of  the  fiber.  If  steeped  in  clear  water  the  fiber  is  of  a  light  color,  while 
1  The  fiber  from  C.  capsularis  is  generally  longer  than  that  from  C.  olitorius. 


VARIETIES  OF  JUTE  763 

if  steeped  in  muddy  water  the  fiber  takes  a  dark-gray  color.  Retting 
in  running  water  takes  longer  than  in  stagnant  water.  In  running  water 
the  inside  bundles  of  the  heap  rot  quicker  than  the  outside  bundles, 
producing  fiber  of  uneven  quality.  The  heap  is  therefore  broken  up  and 
the  inside  bundles  removed  when  ready,  the  outside  bundles  being  kept 
for  two  or  three  days  longer  in  the  water. 

Separation  or  stripping  of  the  fiber  from  the  stem  must  be  accomplished 
within  a  couple  of  days  of  the  finishing  of  the  retting  process.  Standing 
up  to  the  waist  in  the  fetid  water,  the  "  raiyat  "  proceeds  to  take  as  many 
stalks  as  he  can  grasp  in  his  hand,  and  with  a  piece  of  wood  in  his  right 
hand  to  beat  them  flat  at  the  end.  Then  he  gives  them  a  few  more  blows, 
deftly  turning  the  bundle  with  the  left  hand  meanwhile.  He  then  breaks 
the  bundle  about  12  ins.  from  the  end — first  one  way  and  then  the  other. 
A  few  more  blows  on  the  water  and  the  boon  falls  out,  leaving  the  fiber 
clear.  He  now  takes  hold  of  the  separated  fiber  with  both  hands  and 
jerks  the  stems  backward  and  forward  on  the  surface  of  the  water.  After 
a  few  jerks  the  fiber  is  cleared  off  the  stalks.  Next,  after  dashing  the  fiber 
repeatedly  on  the  water  to  wash  it  and  remove  impurities,  and  wringing  as 
much  water  as  possible  from  the  handful  of  fiber,  he  passes  it  out  on  to 
dry  land  to  be  hung  out  and  dried  in  the  sun.  A  man  can  thus  separate 
about  70  lbs.  (dry  weight)  of  fiber  in  ten  hours.  The  yield  of  fiber 
is  only  about  4^  percent  of  the  green  weight  of  the  stems — in  fact,  the 
yield  in  fiber  from  all  the  plants  with  which  we  have  to  deal  is  extremely 
small:  Sisal,  3  to  4^  percent;  furcroya.  If  to  2^  percent;  sanseveria,  2  to  3 
percent;  phormium,  12  to  15  percent;  flax,  5  percent. 

3.  Varieties  of  Jute. — Jute  is  often  called  by  the  name  Calcutta  hemp, 
owing  to  the  fact  that  most  of  the  commercial  jute  passes  through  Calcutta. 
It  is  mostly  exported  in  the  unbleached  condition.  The  trade  names  for 
the  different  qualities  of  jute  are  fine,  medium,  common,  poor,  rejections, 
and  cuttings. 

Kerr  ^  enumerates  the  following  varieties  of  jute  as  being  the  most 
common  in  trade: 

(a)  Ultariya,  or  northern  jute,  by  far  the  best  variety,  as  it  possesses  the  best 
qualities  as  regards  length,  color,  and  strength;  it  is  never  equal  to  the  Desi  and 
Deswal  varieties,  however,  in  softness.  (6)  Deswal,  which  is  next  in  commercial 
value,  is  chiefly  desirable  on  account  of  its  softness,  fineness,  bright  color,  and  strength, 
(c)  Desi  jute  has  a  long,  fine,  soft  fiber,  but  it  has  the  defects  of  being  fuzzy  and  of  a 
bad  color,  (d)  Deora  jute  is  strong,  coarse,  black,  and  rooty,  and  is  much  overspread 
with  runners;  it  is  used  for  the  manufacture  of  rope,  (e)  Narainganji  jute  is  very 
good  for  spinning,  being  soft,  strong,  and  long;  but  the  fiber  as  it  appears  in  trade 
has  a  foxy-brown  color  which  detracts  from  its  value,  though  this  defect  is  apparently 
due  to  imperfect  steeping.  (/)  Bakrabadi  excels  particularly  in  color  and  softness. 
ig)  Bhalial  jute  is  very  coarse,  but  strong,  and  is  in  demand  for  the  manufacture  of 

1  Report  on  Jute  in  Bengal,  1874. 


r64 


JUTE,    RAMIE   AND    HEMP 


rope,  (h)  Karimxjanji  is  a  fine  variety,  long,  very  strong,  and  of  good  color,  (i)  Mir- 
ganji  is  of  medium  quality,  (j)  Jangipuri  jute  is  of  short  fiber,  weak,  and  of  a  foxy- 
brown  color,  and  not  suitable  for  spinning. 

Chaudhury  gives  the  following  glossary  of  Indian  terms  as  applied 
to  the  jute  fiber: 

Ashmara:    Weak  stuff. 

Batch  Pat:  Fiber  from  immature  plants  rejected  at  the  time  of  thinning. 

Bukchhal:    Barky  portion  of  the  fiber  at  some  middle  places,  due  to  plants  being 

allowed  to  grow  after  inundation  and  the  water  has  subsided. 
Croppy:       Fiber  having  rough  and  hard  top  ends. 
Fui:  Fiber  of  superior  quahty. 

Flabby:        Wanting  in  firmness — loose. 
Fid  Pat:      Immature   stuff   cut  before  flowering.     This  fiber   is    excellent    in 

color,  but  somewhat  weak  and  gummy. 
Knotty:        Full  of  knots.     Ivnot  is  a  portion  of  fiber  agglutinated  which  resists 

separation;  mainly  due  to  an  insect  bite  or  puncture  on  the  growing 

plant. 
Mossy:        The  lowland  swamped  jute  with  numerous  adventitious  roots  (or 

ex-traneous  vegetable  matter). 
Rooty:  The  jute  is  called  by  this  name  if  from  the  lower  part  of  the  fiber  the 

gum  and  bark  are  not  wholh'  removed,  and  in  which  the  fibers 

stick  together. 
Specky:        Containing  patches  of  outer  bark  here  and  there. 
Sticky:         With  pieces  of  stick  or  pith  among  the  fiber  (usually  in  small  plants 

from  the  Daisee  district). 

4.  Microscopy  of   Jute. — According  to  Hohnel,   the  bast-cells  of  the 
jute  fiber  are  from  1.5  to  5  mm.  in  length,  and  from  20  to  25  microns  in 

thickness,  the  mean 
ratio  of  the  length 
to  the  breadth  being 
about  90 ;  conse- 
quently the  elements 
of  the  jute  fiber  are 
relatively  short.  In 
cross-section  the  jute 
fiber  shows  a  bundle 
of  several  elements 
bound  together; 
these  are  more  or 
less  poh'gonal  in 
outline,  with  sharply 
defined  angles.  Be- 
tween the  separate  elements  is  a  narrow  median  layer  (Figs.  306  and 
307),  which,  however,  does  not  give  a  much  darker  color  with  iodine  and 
sulfuric  acid  than  the  cell-wall  itself.     The  lumen  is  about  as  wide,  or  at 


306.— Jute  Fiber, 
tudinal  views; 


(X300.) 
c,  ends. 


a,  Cross-sections;  b, 
(Cross  and  Bevan.) 


longi- 


MICROSCOPY  OF  JUTE  765 

times  even  wider,  than  the  cell-wall,  and  in  cross-section  is  round  or  oval. 
Longitudinally  the  lumen  shows  remarkable  constrictions  or  irregular 
thicknesses  in  the  cell-wall  (Fig.  308) ;  though  toward  the  end  of  the 
fiber  the  lumen  broadens  out  considerably,  causing  the  cell-wall  to  become 
very  thin.  Externally  the  fiber  is  smooth  and  lustrous,  and  has  no  jointed 
ridges  or  transverse  markings,  such  as  seen  in  linen  or  most  other  bast 
fibers. 


Fig.  307. — Cross-section  of  Jute  Straw.  Showing  transverse  section  of  portion  of 
bast  only,  giving  the  anatomy  of  the  fibrous  tissue,  the  form  of  the  bast-cells,  and 
the  thickening  of  the  cell-walls.     (Cross  and  Bevan.) 


Mliller  gives  the  following  method  for  the  isolation  of  pure  cellulose 
from  jute:  2  grams  of  the  material  are  dried  at  from  110°  to  115°  C. 
In  order  to  remove  wax,  etc.,  it  is  next  treated  with  a  mixture  of  alcohol 
and  benzol,  and  is  subsequently  boiled  with  very  dilute  ammonia  water. 
The  softened  mass  is  then  pulverised  in  a  mortar,  and  placed  in  a  large, 
glass-stoppered  flask  with  100  cc.  of  water.  From  5  to  10  cc.  of  a  solution 
of  2  cc.  of  bromine  in  500  cc.  of  water  are  added  until  a  permanent  yellow 


766 


JUTE,   RAMIE   AND   HEMP 


is  obtained  after  standing  twelve  to  twenty-four  hours.  The  substance 
is  then  filtered,  washed  with  water,  and  heated  to  boiling  with  water 
containing  a  little  ammonia.  After  this  it  is  fil- 
tered, washed,  and  again  treated  with  the  bromine 
solution,  as  above  indicated,  until  a  permanent 
yeilow  color  is  obtained.  The  fiber  is  then  boiled 
with  dilute  ammonia,  and  on  filtering  and  washing 
leaves  a  residue  of  pure  white  cellulose. 

5.  Chemical  Properties  of  Jute. — In  its  chemical 
composition  jute  is  apparently  quite  different  from 
linen  and  cotton,  being  composed    of    a    modified 
form  of  cellulose  known    as    lignocellulose    or  bas- 
tose.     Bastose,  properly  speaking,  is  a    compound 
of  cellulose  with  lignin.      It    behaves  quite  differ- 
ently from  cellulose  toward  various  reagents,  its  chief 
-p       308  —J  t     Fib  r    ^^^^tinction  being  that  it  is  colored  yellow  by  iodine 
(X300.)  (Micrograph  ^^^  sulfuric  acid,  whereas  pure  cellulose  is  colored 
by  author.)  blue.     With  dilute  chromic  acid,  to  which  a  little 

hydrochloric  acid  has  been  added,  jute  gives  a  blue 
color.  When  treated  with  an  ammoniacal  solution  of  copper  oxide  the 
fibers  swell  considerably,  but  do  not  readily  dissolve.     With  chlor-iodide 


Fig.  309. — Jute  Fiber.     ( X300.)     L,  Lumen;  C,  constrictions  in  lumen;  E,  end  of  fiber. 

(Micrograph  by  author.) 


CHEMICAL   PROPERTIES   OF   JUTE 


767 


of  zinc  jute  gives  a  yellow  color.     The  following  table  gives  the  princi- 
pal reactions  used  to  distinguish  cellulose  from  bastose:* 


Reagent. 

Cellulose. 

Bastose. 

Iodine  and  sulfuric  acid 

Aniline  sulfate  and  sulfuric  acid. 
Basic  dyestuffs 

Blue  color 
No  change 
No  change 
No  change 
Quickly  dissolves 

Yellow  to  brown  color 
Deep-yellow  color 
Becomes  colored 
Quickly  decomposes 
Swells,  becomes  blue, 
dissolves 

Weak  oxidising  agents 

Schweitzer's  reagent 

and  slowly 

A  solution  of  ferric  ferricyanide  ^  colors  ligno-cellulose  a  deep  blue, 
owing  to  the  deoxidation  of  the  ferric  compound  by  the  hgnone.  This 
reaction  is  useful  in  following  the  progressive  elimination  of  the  lignone 
constituents  in  the  isolation  of  pure  cellulose  from  jute,  etc. 

The  chief  chemical  difference  between  jute  and  the  pure  cellulose 
fibers  is  in  the  ability  of  the  former  to  combine  directly  with  basic  dye- 
stuffs.  In  fact  it  acts  in  this  respect  similar  to  cotton  which  has  been 
mordanted  with  tannic  acid.  Jute  is  also  more  sensitive  to  the  action  of 
chemicals  in  general  than  cotton  or  linen.  On  this  account  it  cannot  be 
bleached  with  much  success,  as  treatment  with  alkalies  and  bleaching 
powder  weakens  and  disintegrates  the  fiber  to  a  considerable  extent. 
Schoop  recommends  boiling  jute  in  a  soap  solution  for  the  purpose  of 
cleaning  and  preparing  it  for  bleaching  or  dyeing;  the  strength  of  the 
fiber  is  but  little  diminished  and  the  luster  is  improved,  also  the  fiber 
is  made  soft  and  pliable.  The  use  of  sodium  silicate,  soda  ash  or  caustic 
soda  is  not  to  be  recommended.  Lime  water  makes  the  fiber  brittle, 
while  ammonia  gives  it  a  harsh  feel  and  injures  the  luster. 

It  must  be  borne  in  mind  that  the  jute  fiber  is  a  lignocellulose  composed 
of  cellulose  units  about  |  in.  in  length  cemented  together  by  lignone  com- 
ponents. In  bleaching  processes  where  a  full  white  is  obtained,  these 
lignone  substances  are  removed  and  this  leads  to  the  structural  disinte- 
gration of  the  fiber. 

When  jute  is  hydrolysed  by  heating  with  1  percent  sulfuric  acid  in 

1  According  to  Cross  and  Bevan,  the  jute  fiber  may  be  regarded  as  an  anhydro- 
aggregate  of  three  separate  compounds:  (a)  A  dextro cellulose  allied  to  cotton,  (b)  a 
pentacellulose  yielding  furfural  and  acetic  acid  on  hydrolysis;  (c)  lignone,  a  quinone 
which  is  converted  by  chlorination  and  reduction  into  derivatives  of  the  trihydric 
phenols . 

-  This  is  the  green  solution  resulting  from  the  interaction  of  solutions  of  ferric 
chloride  and  potassium  ferricyanide. 


768 


JUTE,   RAMIE   AND   HEMP 


an  autoclave  to  110°  C.  small  quantities  of  formic  and  acetic  acids  are 
produced.  Under  similar  conditions  cotton  does  not  yield  these  acids. 
Cross  ^  consequently  considers  that  the  ligno-cellulose  molecule  contains 
formyl  and  acetyl  groups. 

The  jute  fiber  is  relatively  weak  when  compared  with  other  bast 
fibers,  and  the  chief  reasons  for  its  prominence  among  the  textile  fibers 
are  its  fineness,  silk-like  luster  and  adaptability  for  spinning.  It  is  also 
a  relatively  soft  fiber,  differing  in  this  respect  from  the  coarse  cordage 
fibers.  In  India  the  natives  weave  it  into  mats  and  a  coarse  cloth  for 
fabrics.  The  plant  is  also  easy  to  cultivate,  and  returns  a  large  yield 
of  fiber.  The  chief  defect  of  jute  is  its  lack  of  durability;  when  exposed 
to  dampness  it  rapidly  deteriorates;  and  even  under  ordinary  conditions 
of  wear,  the  fiber  gradually  becomes  brittle  and  loses  much  of  its  strength. 
Owing  to  these  defects  jute  cannot  be  used  successfully  to  substitute 
Manila  hemp  or  sisal  in  the  making  of  rope  or  binder  twine.  The  bleached 
fiber  is  especially  liable  to  such  deterioration;  it  gradually  loses  its  white- 
ness, and,  evidently  due  to  oxidation,  becomes  dingy  and  yellowish  brown 
in  color. 

Samples  of  jute  fiber  exposed  for  two  hours  to  steam  at  2  atmos- 
pheres, followed  by  boiling  in  water  for  three  hours,  and  again  steamed 
for  fom'  hours,  lost  21.39  percent  by  weight,  being  about  three  times 
as  great  a  loss  as  that  suffered  by  hemp,  Manila  hemp,  phormium,  and 
coir.  A  similar  test  for  jute  with  flax  hemp,  ramie,  and  other  fibers  showed 
as  great  a  loss,  while  flax  lost  less  than  4  percent  and  ramie  a  small  fraction 
under  1  percent.  Contrary  to  the  statements  of  Cross  and  Bevan  that 
the  jute  fiber  is  completely  decomposed  by  heating  with  water  or  steam 
to  120°  to  130°  C.  Schoop  has  observed  that  only  a  slight  decomposition 
sets  in  at  250°  to  300°  C;  in  other  words  jute  is  as  resistant  towards 
hot  water  as  either  linen  or  hemp. 

6.  Analysis  of  Jute. — Analysis  of  jute  shows  it  to  consist  of  the 
following : 


Constituents. 

Nearly  Colorless 

Specimen, 

Percent. 

Fawn-colored 

Fiber, 

Percent. 

Brown 

Cuttings, 
Percent. 

Ash 

Water  (hygroscopic) 

Aqueous  extract 

0.68 
9.93 
1.03 
0.39 
64.24 
24.41 

9.64 

1.63 

0.32 

63.05 

25.36 

12.58 
3  94 

Fat  and  wax 

Cellulose 

Incrusting  and  pectin  matters .... 

0.45 
01.74 
21.29 

Berichle,  1910,  p.  1526. 


ANALYSIS  OF  JUTE  769 

The  ash  of  jute  consists  principally  of  silica,  lime,  and  phosphoric 
acid;  manganese  is  nearly  always  present  in  small  amount.  The  ash  in 
completely  dry  jute  varies  from  0.9  to  1.75  percent. 

According  to  Wiesner,  fresh  jute  contains  about  6  percent  of  hygro- 
scopic moisture  and  brown  jute  about  7  percent.  When  completely 
saturated  with  moisture  the  former  will  contain  about  23  percent  and  the 
latter  24  percent.  The  Turin  Congress  adopted  a  regain  of  13|  percent 
for  the  conditioning  of  jute. 

Dubosc  ^  gives  the  following  example  of  an  analysis  of  jute : 

(1)  Estimation  of  total  lime. — The  jute  is  treated  for  forty-eight  hours  with  a  4 
percent  solution  of  pure  hydrochloric  acid,  and  the  lime  (originally  present  as  free  Hme 
or  pectate  of  lime)  is  thrown  down  by  ammonium  oxalate;  22  grams  of  jute  gave 
1.837  grams  of  lime.  (2)  Estimation  of  pedic  acid. — The  jute  after  being  treated  with 
hydrochloric  acid,  is  washed  and  macerated  for  forty-eight  hours  with  a  2  percent 
solution  of  caustic  soda;  filter,  wash,  and  add  the  washings  to  the  filtrate,  which  is 
colored  red  in  consequence  of  the  presence  of  sodium  pectate.  The  pectic  acid  is 
thrown  by  hydrochloric  acid,  and  weighed;  the  sample  gave  5.455  grams  of  pectic 
acid,  which  would  correspond  to  0.673  gram  of  hme  combined  as  calcium  pectate. 
The  amount  of  free  lime  therefore  is  equal  to  1.164  grams.  (3)  Estimation  of  pectose. — 
The  jute  freed  from  lime  and  pectates  is  treated  for  two  hours  with  a  boiling  2  percent 
solution  of  hydrochloric  acid.  The  pectose  is  thereby  converted  into  pectin,  which 
precipitated  by  alcohol;  the  sample  gave  0.05  percent  of  pectose.  (4)  Estimation  of 
cellulose. — The  jute  remaining  from  the  previous  treatments  is  treated  for  eight  days 
with  an  ammoniacal  copper  solution  (as  concentrated  as  possible),  and  filtered  with  a 
suction  pump  tlu'ough  asbestos.  Wash  with  ammoniacal  copper  solution,  and  pre- 
cipitate the  cellulose  from  the  filtrate  with  very  dilute  hydrochloric  acid;  the  sample 
gave  50  percent  of  cellulose.  (5)  Estimation  of  paracellulose. — The  residue  from  the 
last  determination  is  treated  for  an  hour  at  100°  C.  with  hydrochloric  acid,  which 
renders  the  paracellulose  soluble  in  ammoniacal  copper  solution.  The  treated  residue 
is  therefore  extracted  with  this  reagent,  and  precipitated  from  the  filtrate  with  hydro- 
chloric acid;  the  sample  gave  11.4  percent  of  cellulose.  (6)  Estimation  of  cutose. — The 
residue  is  treated  with  dilute  caustic  potash  at  100°  C,  in  which  the  cutose  is  soluble. 
From  the  filtrate  it  is  precipitated  with  sulfuric  acid;  the  sample  gave  2.00  percent 
of  cutose.  (7)  Estimation  of  vasculose. — The  residue  from  the  previous  treatment  is 
treated  for  one  hour  with  dilute  nitric  acid,  washed,  and  then  macerated  with  a  dilute 
soda  solution.  From  the  dark  brown  filtrate  the  vasculose  is  precipitated  with  hydro- 
chloric acid;  the  sample  gave  20.5  percent  of  vasculose.  (8)  Estiination  of  nieta- 
cellulose. — The  residue  is  washed  and  gives  by  difference  the  amount  of  metacellulose. 
(9)  Estimation  of  fats. — The  jute  is  macerated  for  eight  days  with  petroleum  spirit, 
and  the  light  yellow  filtrate  evaporated  to  dryness.  (10)  Estimation  of  gums. — The 
residue  from  the  fat  extraction  is  further  extracted  successively  with  ether  and  then 
with  alcohol,  and  the  extracts  evaporated  and  weighed.  (11)  Estimation  of  soluble 
pectates. — Besides  calcium  pectate  jute  also  contains  pectates  soluble  in  water.  To 
determine  these,  the  jute  remaining  after  the  previous  two  estimations  is  extracted  in 
a  closed  vessel  with  distilled  water  for  fourteen  days.  In  the  filtrate  the  soluble  pectates 
are  precipitated  with  alcohol  and  weighed. 

1  Bull.  Sac.  Ind.  Mulh.,  1903. 


770  JUTE,   RAMIE   AND   HEMP 

The  sample  of  jute  in  the  above  analysis  gave  the  following  results: 

Percent. 

Fatty  substances 0 .  049 

Gums  soluble  in  ether 1 .  600 

Gums  soluble  in  alcohol 0 .  637 

Pectates  soluble  in  water 1 .272 

Pectate  of  lime 6 .  128 

Lime 1.104 

Pectose 0.050 

Cellulose 50.000 

Paracellulose 11 .  400 

Metacellulose 5.200 

Cutose 2.000 

Vasculose 20, 500 

7.  Uses  of  Jute. — Jute  is  principally  used  for  the  making  of  coarse 
woven  fabrics,  such  as  gunny  sacks  and  bagging,  where  cheapness  is  of 
more  consequence  than  durability.  It  also  finds  considerable  use  in  the 
tapestry  trade,  being  used  as  a  binding-thread  in  the  weaving  of  carpets 
and  rugs.  On  account  of  its  high  luster  and  fineness,  it  is  also  adapted 
for  the  preparation  of  cheap  pile  fabrics  for  use  in  upholstery.  Of  late 
years  a  variety  of  novelty  fabrics  for  dress  goods  have  also  been  made 
from  jute,  used  in  conjunction  with  woolen  yarns. 

Jute  has  also  been  used  extensively  as  a  substitute  for  hemp,  for  which 
purpose  the  former  is  rendered  very  soft  and  pliable  by  treatment  with 
water  and  oil.  A  mixture  of  20  parts  of  water  with  2.5  parts  of  train-oil 
is  sprinkled  over  100  parts  of  jute  fiber.  It  is  left  for  one  to  two  days, 
then  squeezed  and  heckled,  whereby  the  fibers  become  very  soft  and  iso- 
lated. Jute  is  also  largely  used  in  the  manufacture  of  twine,  window 
cord,  and  smaller  sizes  of  rope.  Owing  to  its  cheapness,  it  is  used  to 
adulterate  other  more  valuable  fibers,  but  due  to  its  tendency  to  rapid 
deterioration,  its  use  in  this  connection  should  not  be  encouraged.  The 
"  jute  butts  "  and  miscellaneous  waste  are  extensively  employed  as  a  raw 
material  in  the  manufacture  of  paper. 

Jute  is  the  cheapest  fiber  used  in  textile  manufacturing,  and  it  is 
employed  in  greater  quantities  than  any  other  except  cotton.  All  the 
jute  of  commerce  comes  from  India,  and  until  recent  years,  Scotch  and 
Indian  mills  supplied  practically  all  the  manufactured  jute  appearing  in 
international  trade.  The  coarse,  loosely  woven  cloth  used  in  baling  cotton 
is  about  the  only  jute  fabric  woven  in  this  country.  Though  America  uses 
each  year  several  hundred  million  jute  bags  for  the  shipment  of  its  raw 
products,  these  bags  are  made  from  imported  burlap.  The  United  States 
each  year  pays  for  jute  bags  and  burlap  a  considerably  greater  sum  than 
that  paid  for  the  combined  imports  of  all  piece-goods  of  wool,  silk,  cotton, 
flax,  and  hemp;  in  fact,  for  the  year  1919  it  was  more  than  twice  as  great. 


STATISTICS  OF  JUTE  771 

The  waste  arising  in  the  spinning  of  jute  mixed  with  similar  waste  from 
linen  and  hemp  is  manufactured  into  a  product  known  as  Kosmos  fiber  or 
artificial  wool. 

By  treatment  with  strong  caustic  soda  solutions  (36°  to  40° 
Be.)  jute  is  converted  into  a  woolly  sort  of  fiber.^  Jute  is  much  more 
sensitive  toward  acids  than  either  linen  or  hemp;  concentrated  mineral 
acids  readily  dissolve  the  fiber;  dilute  mineral  acids  even  as  minute  traces 
left  in  the  fiber,  quickly  rot  it.  Sulfurous  acid  and  sodium  bisulfite  are 
without  bad  effect,  and  the  same  is  also  true  of  the  organic  acids.  Chloride 
of  lime  and  neutral  hypochlorite  of  soda  are  used  for  bleaching  jute. 
Some  unusual  results  were  obtained  during  the  War  with  jute  by  the 
Deutsche  Faserstoff-Gesellschaft.  By  a  special  process  of  chemical 
treatment  a  long,  fine,  and  beautiful  fiber  was  produced  therefrom,  a 
fiber  which  can  readily  be  spun  on  the  worsted  system,  pure  or  mixed  with 
wool.  Shoddy  made  from  old  jute  rags  can  also  be  spun  on  the  worsted 
or  woolen  system.  Serges  made  from  old  jute  rags  or  cloth  made  from 
half  wool  and  half  jute,  wool  or  piece  dyed,  were  used  for  women's  cos- 
tumes, overcoating,  etc.  Furthermore,  sweaters  and  vests  were  made  from 
all  jute  worsted  yarn,  and  it  has  been  difficult  to  recognise  them  as  being 
made  of  such.  The  Deutsche  Faserstoff-Gesellschaft  claims  that  jute  repre- 
sents the  cheapest  fiber  suitable  for  worsted  yarn  that  has  been  discovered. 
8.  Statistics  of  Jute. — Jute  was  first  introduced  into  Europe  about  the 
year  1795.  It  has  been  used  for  spinning  since  1830.  At  the  present 
time  there  is  more  jute  used,  weight  for  weight,  than  any  other  textile  fiber 
with  the  exception  of  cotton.  Calcutta  is  the  center  of  the  jute  industry 
and  through  this  market  the  rest  of  the  world  draws  its  supply  of  either 
the  raw  jute  fiber  or  manufactured  jute  products.  The  manufacture  of  jute 
bags  has  been  developed  in  India  to  a  surprising  extent,  and  these  bags  or 
"  gunny  sacks  "  as  they  are  generally  called,  which  formerly  were  made  in 
Europe  are  practically  all  marketed  now  from  Calcutta.  The  following  table 
shows  the  number  of  jute  bags  exported  from  Calcutta  in  the  year  1920: 
Exported  to  No.  of  Bags. 

Great  Britain 48,000,000 

Belgium 15,600,000 

France 13,800,000 

Egypt 13,000,000 

Chile  and  Peru 59,400,000 

Cuba 22,500,000 

United  States 71,800,000 

Japan 13,800,000 

China 32,400,000 

Java 24,600,000 

Cochin  China 12,400,000 

Australia 34,100,000 

1  See  Fdrb.  Zeit.,  1900,  p.  325. 


772 


JUTE,   RAMIE   AND   HEMP 


The  production  of  jute  since  1915  has  been  falhng  off,  as  shown  by  the 
following  table: 

Acreage  and  Production  of  Jute 


Production, 

Equivalent, 

Bales 

\ear. 

Acreage. 

400-lb.  Bales. 

in  Gross  Tons. 

per  Acre. 

1909-13  (5-year  average)  . . 

2,949,600 

7,905,380 

1,411,675 

2.68 

1914 

3,169,600 

8,751,800 

1,562,821 

2.76 

1915         

3,358,700 

10,443,900 

1,864,982 
1,326,554 

3  11 

1916 

2,377,300 

7,428,700 

3.12 

1917 

2,671,850 

8,305,600 

1,483,143 

3.11 

1918 

2,500,382 

7,019,088 

1,253,409 

2.81 

1919 

2,821,575 

8,486,234 

1,515,399 

3.01 

1920 

2,508,773 

5,978,592 

1,067,606 

2.38 

1921 

1,518,358 

4,052,609 

723,680 

2.67 

1922 

1,456,806 

4,236,828 

756,596 

2.91 

The  largest  consumers  of  Indian  jute  are  the  Calcutta  mills,  which 
take  approximately  half  of  the  total  crop,  but  the  United  States  and 
European  countries  import  large  quantities.  The  following  table  shows 
the  exports  of  jute  from  British  India  to  various  countries: 


United  Kingdom 

Germany 

United  States .  .  . 

France 

Italy 

Spain 

Others 

Total 


1910-14. 

(5-year 
Average) . 


1920. 


1921. 


1922. 


1923, 

(April  to 
Nov.) 


(In  Gross  Tons.) 


301,864 
164,392 
95,621 
76,507 
38,109 
21,764 
66,131 


764,388 


310,670 
3,609 
77,649 
80,731 
28,076 
19,138 
71,941 


591,814 


136,023 
72,068 

110,005 
50,044 
22,869 
23,857 
57,548 


472,414 


90,835 
144,013 
66,422 
55,837 
25,325 
22,120 
63,133 


467,685 


112,945 
95,263 
58,626 
39,824 
22,226 
19,329 
44,861 


393,074 


Raw  jute  imports  into  the  United  States,  however,  are  of  minor 
importance  compared  with  the  imports  of  burlap,  the  principal  product 
manufactured  from  jute.  Imports  of  burlap  each  year  are  several  times 
as  great  in  value  as  the  imports  of  raw  jute.  The  following  table  shows 
the  imports  into  the  United  States  of  raw  jute,  jute  butts,  jute  bags  and 
fabrics : 


LIGNOCELLULOSE  773 

Imports  of  Jute  and  Jute  Products  into  the  United  States 


Year. 


1909-13  (5-year  average) 

1919 

1920 

1921 

1922  (to  September  21) .  , 


Jute  and 

Jute  Butts, 

Tons. 


103,294 
62,332 
96,039 
62,416 
49,861 


Jute 

Bags, 

Pounds. 


47,944,000 
46,216,000 
51,427,000 
65,250,000 
41,144,015 


Jute 
Fabrics, 
Pounds. 


389,644,000 
446,056,000 
571,534,000 
475,141,000 
376,792,105 


The  greater  part  of  the  raw  jute  imported  into  the  United  States  is 
consumed  in  the  manufacture  of  the  heavy  coarse  wrapping  known  as 
cotton  bagging,  used  for  covering  raw  cotton.  About  90,000,000  yards 
of  this  fabric  are  required  annually  to  cover  the  cotton  crop  of  the  country, 
and  of  this  amount,  practically  all  is  manufactured  in  the  United  States. 
On  the  other  hand,  in  spite  of  the  fact  that  the  United  States  is  the 
world's  largest  consumer  of  burlap,  the  American  production  of  burlap 
is  insignificant. 

Production  of  Jute  Goods  in  the  United  States  in  1914 


Bags  and  bagging,  square  yards . 

Rope,  pounds 

Twine,  pounds 

Yarn,  pounds 

Carpets  and  rugs,  square  yards. 


Total . 


Production. 


131,827,658 

26,814,920 

55,282,159 

69,827,005 

4,862,302 


Value. 


$  6,441,000 
2,097,000 
5,268,000 
7,358,000 
1,172,000 


$22,336,000 


Price  of  Jute  in  New  York  (Cents  per  Pound) 


1913. 
1914. 
1915. 
1916. 


6.6 

1917 

10.5 

7.5 

1918 

13.0 

5.1 

1919 

9.3 

7.5 

1920 

11.0 

9.  Lignocellulose. — Jute  differs  somewhat  from  the  previously  con- 
sidered vegetable  fibers  in  that  it  does  not  consist  of  comparatively  pure 
cellulose,  but  contains  a  large  amount  of  modified  cellulose  known  as  ligno- 
cellulose. As  this  latter  compound  differs  essentially  both  in  its  chemical 
composition  and  reactions  from  ordinary  cellulose,  it  will  be  of  immediate 


774 


JUTE,   RAMIE   AND   HEMP 


interest  to  make  a  study  of  this  product,  not  only  in  connection  with  its 
direct  association  with  jute,  but  also  as  a  general  substance  occurring  in 
other  vegetable  fibers  as  well.  It  is  doubtful  if  lignocellulose  can  be 
regarded  as  a  simple  chemical  body,  its  reactions  tending  to  indicate  that 
it  is  a  complex  of  several  different  bodies.  The  lignocellulose  of  jute  has 
a  lower  percentage  of  oxygen  than  that  present  in  normal  cellulose,  as 
follows : 


Normal  Cellulose 
(Cotton),  Percent. 


Lignocellulose 
(Jute),  Percent. 


There  are  two  distinct  chemical  differences  between  normal  cellulose  and 
lignocellulose:  (1)  Normal  cellulose  does  not  react  with  chlorine,  whereas 
lignocellulose  readily  combines  with  chlorine  to  yield  definite  products; 
(2)  normal  cellulose  does  not  yield  furfural  whereas  lignocellulose  does, 
thereby  indicating  the  possibility  of  its  containing  an  oxycellulose 
derivative. 

The  formation  of  lignocellulose  is  to  be  considered  as  a  process  of 
thickening  by  incrustation,  and  recent  researches  in  this  matter  indicate 
this  incrustation  is  a  process  of  forming  adsorption  compounds;  the 
colloidal  hydrated  celluloses  at  first  elaborated  taking  up  soluble  colloidal 
products  from  solution  in  the  cambium  fluids.^  Chemically  the  forma- 
tion of  lignin  is  to  be  regarded  as  a  combination  of  cellulose  with  acid 
and  unsaturated  ketonic  groups.  Conversely,  processes  which  attack 
these  groups  resolve  the  lignin  into  soluble  derivatives  and  cellulose 
which  is  resistant  and  insoluble.  The  separation  of  the  cellulose  is  attended 
by  disintegration,  and  the  fiber  is  resolved  into  its  component  cell  units, 
which  are  usually  2  to  3  mm.  in  length  and  0.02  to  0.03  mm.  in  diameter. 
The  elimination  of  the  non-cellulose  constituents  is  also  attended  by 
considerable  loss  in  weight.  In  jute  the  amount  of  cellulose  is  about 
70  to  80  percent,  and  the  lignone  about  30  to  20  percent. 

Lignone  reacts  quantitatively  with  chlorine  combining  in  a  char- 
acteristic and  invariable  proportion.  In  the  case  of  jute  this  proportion 
is  8  percent  of  the  lignocellulose.  The  cellulose  and  lignocellulose  in  jute 
and  similar  fibers  may  be  separated  by  a  treatment  with  chlorine  the 
lignocellulose  combining  with  chlorine  to  yield  a  product  soluble  in  a 
solution  of  sodium  bisulfite.  Cross  and  Bevan  described  the  following 
method  of  procedure.  A  weighed  amount  (5  grams)  of  the  fiber  is  dried 
1  Wislicenus,  Zeitschr.  Kolloide,  1910,  p.  17. 


LIGNOCELLULOSE  775 

in  a  water-oven,  and  then  boiled  with  a  1  percent  solution  of  caustic  soda 
for  thirty  minutes.  The  mass  is  then  removed,  and  after  pressing  out 
most  of  the  liquid  it  retains,  it  is  treated  with  a  current  of  chlorine  gas 
for  one-half  to  one  hour.  It  is  then  washed  and  slowly  heated  with  a 
2  percent  solution  of  sodium  bisulfite.  When  the  liquid  reaches  the 
boiling  point,  0.2  percent  of  caustic  soda  is  added,  and  the  boiling  allowed 
to  proceed  for  five  minutes.  The  residue  consists  of  nearly  pure  cellulose. 
It  is  washed  with  hot  water  and  further  purified  by  a  few  minutes'  treat- 
ment with  a  0.1  percent  solution  of  potassium  permanganate,  again  washed, 
dried,  and  weighed.  Bromine  cannot  be  used  in  this  reaction  in  place 
of  chlorine  as  it  acts  on  the  cellulose  to  some  extent,  giving  a  figure  for 
lignocellulose  from  2  to  5  percent  higher. 

The  furfural  reaction  of  lignocellulose  is  obtained  by  heating  jute 
with  dilute  hydrochloric  acid.  Cross  and  Bevan  give  the  following 
method  of  estimating  furfural  in  jute:  A  weighed  portion  (5  grams)  of 
the  fiber  is  heated  with  100  cc.  of  a  12  percent  solution  of  hydrochloric 
acid  in  a  fiask  connected  with  a  condenser  and  the  tube  of  a  stoppered 
separatory  funnel.  The  distillation  should  proceed  at  the  rate  of  2  cc. 
per  minute,  and  successive  portions  of  30  cc.  each  collected  until  aniline 
acetate  and  hydrochloric  acid  no  longer  yield  a  rose  coloration.  The 
distillate  is  then  treated  with  a  slight  excess  of  sodium  carbonate,  then 
acidified  with  acetic  acid,  and  made  up  to  a  definite  volume  with  sodium 
chloride  solution  containing  approximately  the  same  amount  of  salt  as 
has  been  formed  in  the  distillate.  It  is  next  treated  with  an  aqueous 
solution  of  phenylhydrazine  containing  12  grams  of  the  latter  and  7.5 
grams  of  acetic  acid  in  100  cc.  The  precipitated  h3^drazone  is  washed, 
dried  in  a  vacuum  at  70°  C,  and  weighed.  This  weight  multiplied  by 
the  factor  0.538  gives  the  amount  of  furfural. 

Lignocellulose  also  reacts  with  several  aromatic  compounds  to  give 
colored  bodies.  With  phloroglucinol  and  hydrochloric  acid  it  gives  a 
crimson  color,  with  phenylhydrazine  a  yellow  color,  and  with  a  dimethyl- 
paraphenylenediamine  a  crimson  color. 

Cross,  Bevan  and  Briggs  ^  have  shown  that  there  is  a  definite  absorp- 
tion of  phloroglucinol  by  lignocellulose,  and  the  following  method  has  been 
suggested  by  them  for  determining  this  absorption:  A  weighed  quantity 
(2  grams)  of  the  dried  fiber  is  mixed  with  40  cc.  of  a  solution  of  2.5  grams 
of  phloroglucinol  in  100  cc.  of  hj^drochloric  acid  (specific  gravity  1.06). 
After  standing  for  twelve  hours  the  liquid  is  filtei'ed  through  cotton;  10  cc. 
of  the  filtrate  are  then  titrated  with  a  standard  solution  of  formaldehyde, 
and  the  difference  between  the  result  and  a  blank  titration  on  10  cc.  of 
the  original  phloroglucinol  solution  gives  the  measure  of  the  absorption. 
The  standard  solution  for  the  titration  contains  2  grams  of  40  percent 

1  Chem.  Zdt.,  1907,  p.  725. 


776  JUTE,   RAMIE  AND  HEMP 

formaldehyde  mixed  with  500  cc.  of  hydrochloric  acid  (specific  gravity 
1.06).  The  10  cc.  of  phloroglucinol  solution  are  diluted  with  20  cc.  of  the 
hydrochloric  acid  and  heated  to  70°  C,  and  the  aldehyde  solution  is  added 
at  the  rate  of  1  cc.  every  two  minutes  until  all  the  phloroglucinol  has  been 
precipitated,  and  the  liquid  no  longer  gives  a  red  coloration  when  dropped 
on  paper  containing  ground  wool  pulp  (newspaper).  This  test  yielded 
the  following  figures  for  phloroglucinol  absorption: 

Phloroglucinol 
Material.  Absorbed, 

Percent. 

Wood  pulp 7.5 

Jute 4.2 

Esparto  cellulose 0.5 

Cotton 0.2 

Lignocellulose  also  reacts  with  the  bisulfites  of  the  alkali  and  alkaline 
earth  metals;  at  elevated  temperatures  and  under  pressure  being  con- 
verted quantitatively  into  cellulose  and  soluble  sulfonated  products  of 
lignone.  On  this  reaction  is  based  the  manufacture  of  wood-pulp  by  the 
sulfite  process.  Solutions  of  caustic  soda  at  elevated  temperatures  also 
attack  lignocellulose,  separating  the  cellulose  and  giving  ill-defined 
soluble  products  of  lignone.  On  this  reaction  is  based  the  manufacture 
of  soda-pulp. 

Hydriodic  acid  reacts  with  lignocelluloses  with  formation  of  methyl 
iodide.  The  estimation  of  this  latter  volatile  product  is  taken  as  the 
index  or  quantitative  measure  of  the  "  methoxy  "  (OCH3)  groups  present 
in  the  lignocellulose.  This  index  may  also  be  considered  as  the  "  chemical 
constant  of  lignification."  The  following  table  shows  these  constants 
as  determined  for  various  fibers: 

Percent,  OCH3. 

Jute 1.87 

Cotton 0.0 

Flax 0.0 

Hemp 0 .  29 

China  grass 0 .  07 

Sulfite  pulp 0 .  34 

Swedish  filter-paper 0.0 

10.  Ramie  or  China  Grass. —  This  is  a  fiber  obtained  from  the  bast 
of  the  stingless  nettle,  or  Ba'hmeria.  Although  frequently  confounded 
in  trade,  ramie  and  China  grass  arc  in  reality  two  distinct  fibers.  The 
former  (also  known  as  rhea)  is  obtained  from  the  Bcehmeria  tenacissima, 
which  grows  best  in  tropical  and  subtropical  countries.  The  latter  is 
obtained  from  Bcehmeria  nivea.  which  grows  principally  in  the  more 
temperate  climes. 


RAMIE  OR  CHINA  GRASS 


777 


The  term  ramie  or  rhea  was  apparently  derived  from  a  term  in  use  by 
the  inhabitants  of  the  Malay  Archipelago,  and  was  first  brought  into 
European  usage  by  the  Dutch.  During  recent  years  the  supposed  dis- 
tinction between  China  grass  and  ramie  has  been  practically  set  aside. 
As  far  as  the  plants  themselves  are  concerned,  however,  some  distinction 
is  still  preserved;  the  ramie  is  said  to  yield  stronger  fibers  and  is  often 
called  green  ramie,  as  the  leaves  of  the  plant  are  quite  green  in  color;  the 
other  plant  is  often  called  white  ramie  because  its  leaves  have  a  mother- 
of-pearl  whiteness  on  the  under  side. 

The  ramie  plant  is  of  more  robust  habit  and  has  larger  leaves,  which 
are  green  on  both  sides.     The  China  grass  plant  has  leaves  which  are 

white  felted  beneath. 
The  two  species, 
however,  are  so  simi- 
lar in  nature,  and  the 
fibers  are  so  univer- 
sally confounded  with 
one  another,  that  it 
is  only  possible  to 
consider  them  as  a 
single  substance, 
which  will  be  done 
under  the  name  of 
ramie.  There  has 
been  some  discus- 
sion as  to  the  bot- 
anical classification 
of  true  ramie.  Form- 
erly the  old  China 
grass  plant  was 
classed  along  with 
the  stinging  nettles  (  Urtica),  but  in  more  recent  years  this  opinion  has 
been  revised  and  now  both  China  grass  and  ramie  are  ascribed  to  the 
class  of  stingless  or  so-called  "  shooting  "  nettles  (Boehmeria) .  The 
stinging  nettles  are  very  common  plants  and  are  found  distributed 
very  widely  in  most  countries  of  the  world.  They  are  characterised  by 
the  possession  of  fine  stinging  hairs,  while  the  Boehmeria  species  are 
deficient  in  this  feature.  The  common  stinging  nettle  of  Europe 
(  Urtica  dioica)  has  been  utihsed  from  very  early  times  for  the  prep- 
aration of  fish  lines  on  account  of  the  great  strength  of  the  fiber 
obtained  from  it.  Savorgnan  states  that  it  is  known  as  Swedish  hemp 
and  that  the  plant  has  long  been  actively  cultivated  in  Sweden  for  the 
production  of  fiber  employed  in  the  making  of  cordage  and  sail  cloth. 


Fig.  310. — Cross-section  of  Ramie  Stalk. 


778 


JUTE,   RAMIE   AND   HEMP 


The  plant  is  a  snrub,  reaching  4  to  6  ft.  in  height,  and  is  very  hardy. 
It  is  cultivated  largely  in  China  ^  and  India,  and  has  also  been  grown 
successfully  in  America.^ 


Fig.  311. — Cross-section  of  Ramie  Straw.  Showing  transverse  section  of  bast  region 
only;  the  bast  fibers  are  to  be  distinguished  by  their  large  area  from  the  adjacent 
tissue.     (Cross  and  Bevan.) 


1  The  ramie  plant  in  China  is  known  as  Tchow  Ma,  and  is  extensively  cultivated  for 
its  fiber.  From  8000  to  10,000  tons  of  fiber  annually  are  exported  to  Europe,  which 
received  most  of  its  supply  from  this  source.  In  Cochin  China  ramie  is  known  as 
Cay-gai,  in  Bengal,  as  Kankura.  Ramie  is  also  grown  in  Malay,  though  the  Malayan 
plant  exhibits  certain  marked  differences  from  the  Chinese  type,  and  is  usually  regarded 
as  a  distinct  variety. 

2  There  seems  to  be  only  one  American  representative  of  the  stingless  nettle  (the 
Boshmeria  cylindricn) ;  it  is  also  loiown  as  the  false  nettle  and  is  to  be  fovmd  as  a  sort 
of  weed  growing  on  the  waste  lands  extending  from  Ontario  and  Minnesota  to  Florida 
and  Kansas.  It  has  no  value,  however,  as  a  fiber-producing  plant,  so  does  not  possess 
any  economic  importance.  There  is  another  somewhat  similar  plant  foimd  in  the 
Sandwich  Islands  (B'vhmeria  stipulans)  and  it  is  of  some  interest  as  it  is  used  to  a 
slight  extent  by  the  natives  for  the  preparation  of  their  kapa.  It  is  interesting  to 
note  in  this  connection  that  in  the  United  States  there  are  apparently  several  varieties 


PROPERTIES   OF  RAMIE   FIBER  779 

The  use  of  China  grass  or  ramie  was  probably  known  to  the  Chinese 
at  a  very  early  period;  some  writers  have  also  attempted  to  show  that  it 
was  used  in  Egypt  several  thousand  years  ago  contemporaneously  with 
flax  for  the  preparation  of  mummy-cloths.^ 

Dr.  Watt  is  of  the  opinion  that  ramie  dates  back  to  great  antiquity  in 
India.  He  states  that  frequent  reference  is  made  in  the  Ramagana  to  a 
garment  called  kshauma,  and  says  that  while  this  word  is  generally 
regarded  as  a  name  for  linen,  it  so  strongly  resembles  the  Chinese  name 
for  ramie  that  there  is  undoubtedly  some  connection  between  the  two. 

Ramie  is  grown  in  almost  unlimited  quantities  throughout  equatorial 
Africa,  India  and  China,  though  the  best  qualities  come  from  the  last 
country.  In  China  ramie  grows  wild  in  large  quantities,  though  it  is 
also  cultivated  in  small  plots  by  the  peasants.  It  is  stated  that  as  far 
as  the  actual  supply  of  the  plant  is  concerned,  the  quantity  appears  to  be 
far  in  excess  of  any  possible  requirements. 

11.  Properties  of  Ramie  Fiber. — The  fiber  of  ramie  is  very  strong 
and  durable,  probably  ranking  first  of  all  vegetable  fibers  in  this  respect. 
It  is  also  the  least  affected  by  moisture.  It  has  three  times  the  strength 
of  hemp,  and  the  fibers  can  be  separated  to  almost  the  fineness  of 
silk. 

Ramie  also  has  the  special  advantage  of  not  rotting  when  exposed 
to  weather  conditions  or  when  immersed  in  water.  It  also  takes  dyestuffs 
rather  readily,  though  in  this  respect  it  is  harder  to  completely  penetrate 
the  fiber  than  is  the  case  with  cotton. 

The  fiber  of  ramie  is  exceptionally  white  in  color,  being  almost  com- 
parable to  bleached  cotton  in  this  respect,  and  does  not  appear  to  have 
any  natural  coloring  matter  at  all.  It  also  has  a  high  luster,  excelling 
linen  in  this  respect. 

From  experiments  made  on  the  tensile  strength  of  isolated  filaments 
of  ramie,  it  appears  that  this  fiber  has  a  breaking  strain  of  from  17  to  18 
grams.  Ramie  degummed  in  the  laboratory  of  Fremy  showed  a  breaking 
strain  of  from  21  to  22  grams,  and  by  very  careful  degumming  it  has 
been  possible  to  attain  a  strength  of  from  35  to  40  grams.  Isolated 
fibers  of  hemp  show  a  breaking  strain  of  only  5  grams. 

Cottonised  ramie  is  fiber  on  which  the  degumming  process  has  been 
carried  too  far,  with  the  result  that  the  individual  filaments  have  been 

of  stinging  nettles  as  indigenous  plants.  The  Indians  were  acquainted  with  its  use 
for  fiber  purposes,  and  employed  it  in  the  making  of  bowstrings  and  twine  on  account 
of  its  great  strength  and  durability.  There  is  a  very  good  sample  of  this  American 
fiber  in  the  Botanical  Museum  of  Harvard  University. 

'  By  some  authorities  it  is  claimed  that  ramie  was  the  fiber  from  which  the  ancient 
Egyptian  mummy  cloths  were  made,  rather  than  from  flax.  This  view  is  supported 
by  the  fact  that  flax  does  not  grow  in  hot  climates. 


780 


JUTE,   RAMIE   AND   HEMP 


more  or  less  separated  into  their  elements;  the  fiber  is  white,  but  without 
the  characteristic  transparency  and  luster  of  ordinary  ramie.^ 

The  brilliant  and  transparent  fabrics  known  in  China  as  A-pou  and 
sold  in  England  under  the  name  of  grass  cloth  are  made  from  ramie. 

Ramie  is  used  to  some  extent  in  the  preparation  of  a  fiber  which  may 
be  classed  as  a  wool  substitute.  The  ramie  is  specially  prepared  for 
this  purpose  and  gives  a  yarn  somewhat  resembling  wool  in  appearance 
and  quality.  The  Stycos  fiber  marketed  to  some  extent  in  the  United 
States  is  a  product  of  this  character.  It  closely  resembles  the  Solidonia 
fiber  used  in  Europe  for  the  same  purpose.  It  can  be  used  alone  or  mixed 
with  wool  before  carding  or  afterward  in  the  drawing  operations  of  pre- 
paring the  yarn. 

The  following  table  gives  the  chief  physical  factors  of  the  ramie  fiber 
in  comparison  with  the  other  principal  fibers: 


Ramie. 

Hemp. 

Flax. 

Silk. 

Cotton. 

Tensile  strength 

Elasticity 

100 
100 
100 

36 

75 
95 

25 
66 
80 

13 
400 
600 

12 
100 

Torsion          

400 

12.  Preparation  of  Ramie. — Having  such  excellent  qualities  as  a  fiber, 
it  would  be  natural  that  ramie  should  have  had  considerable  attention 
bestowed  upon  it.  The  two  main  stages  in  the  preparation  of  the  fiber 
for  spinning  are  decorticating  and  degumming.  As  brought  into  America 
and  Europe  for  use  in  spinning,  ramie  is  always  in  the  decorticated  condi- 
tion and  requires  simply  to  pass  through  a  degumming  operation.  The 
chief  difficulty  in  the  way  of  its  universal  and  widespread  adoption  has 
been  the  lack  of  an  efficient  process  for  properly  decorticating  the  fiber 
from  the  rest  of  the  plant.  In  China  and  India,  where  this  fiber  has  long 
been  employed  for  the  weaving  of  the  finest  and  most  beautiful  fabrics,  the 
decortication  of  the  fiber  is  carried  out  by  hand,  the  stems  being  soaked 
in  water  and  the  bark  scraped  off  by  the  natives.     In  China  a  native  can 

1  A  recent  French  patent  describes  the  following  process  for  preparing  imitation 
wool  from  ramie:  100  kilos,  of  stripped  ramie  are  cut  into  lengths  of  30  to  80  mm. 
and  boiled  for  two  hours  in  1000  liters  of  a  2^  percent  solution  of  sodium  carbonate. 
The  liquor  is  then  run  off,  and  the  material  is  again  boiled  for  6  hours  in  1000  liters 
of  water  to  which  has  been  added  20  liters  of  caustic  soda  of  36°  Be.  After  draining 
and  washing  thoroughly  with  cold  water  the  scoured  fiber  is  hydro-extracted,  dried, 
opened,  and  next  curled  by  working  it  for  one  hour  in  a  cold  bath  containing  1000 
liters  of  water  and  1000  liters  of  caustic  soda  of  36°  B^.  The  excess  of  the  solution  is 
then  pressed  from  the  wet  fiber,  and  the  process  is  completed  by  the  operations  of 
souring,  washing,  drying,  and  carding. 


PREPARATION  OF  RAMIE  781 

produce  about  8  lbs.  of  cleaned  ramie  per  day.^  This,  of  course,  would 
be  impracticable  in  western  countries. 

The  chief  and  perhaps  the  only  reason  that  ramie  has  not  maintained 
its  position  as  a  fiber  plant  is  the  fact  that  it  is  very  difficult  to  isolate 
the  fiber  proper  from  the  rest  of  the  plant  tissues,  and  as  this  can  only  be 
done  up  to  the  present  time  by  hand  labor,  it  is  not  feasible  under  the 
present-day  conditions  to  produce  the  ramie  fiber  in  a  sufficiently  econom- 
ical manner  to  make  it  available  for  industrial  uses  in  competition  with 
linen  and  still  less  with  cotton.  In  ancient  times  there  is  no  doubt  that 
all  the  bast  fibers  employed  for  spinning  and  weaving  were  produced  by 
hand  operations,  and  therefore  ramie  under  these  conditions  was  not 
any  more  difficult  to  obtain  than  the  other  fibers. 

Ramie  has  been  found  in  the  composition  of  hand-woven  fabrics  in 
various  mummy  cases  in  Egyptian  tombs,  dating  as  far  back  as  the  fifteenth 
dynasty;  but  rather  curiously,  this  fiber  then  seems  to  drop  out  of  Egyptian 
industry  as  it  does  not  occur  in  the  later  textile  fabrics,  being  replaced  by 
linen.  The  first  recognition  of  ramie  was  in  Chinese  fabrics  imported  into 
Europe,  and  in  England  these  were  generally  known  as  China  grass  cloth. 
In  Germany  the  fabrics  were  known  as  nettle  cloth  (nessel  tuch),  though 
there  is  a  little  confusion  in  origins  to  be  found  in  this  connection.  This 
vvas  due  to  the  fact  that  the  Romans  apparently  were  acquainted  with 
the  ramie  fiber  (Virgil  in  his  second  song  on  agriculture  evidently  refers 
to  this  fiber)  and  in  the  dissemination  of  the  Roman  culture  throughout 
Europe  no  doubt  this  knowledge  of  ramie  was  carried  to  Germany  and 
other  European  countries  as  they  developed  industrially.  The  fiber, 
however,  that  was  employed  in  Germany  seems  to  have  been  principally 
derived  from  the  nettle  plant  of  considerable  divergence  from  the  oriental 
ramie.  This  nettle  bast  fiber  has  always  been  more  or  less  utilised  in 
Germany,  though  after  cotton  became  the  predominating  factor  in  the 
class  of  vegetable  fibers,  the  nettle  fiber  rapidly  declined  in  importance. 
On  this  account  there  has  always  been  a  kind  of  confusion  in  the  designation 
of  ramie  and  nettle  fiber. 

In  India  and  the  Himalayan  districts  ramie  has  also  been  in  use  from 
prehistoric  times.  In  early  Sanscrit  literature  it  is  often  to  be  met  with 
under  the  name  of  grass  linen;  this  term,  of  course,  being  the  English 
ti-anslation,  though  the  character  of  the  material  described  in  the  Sanscrit 
indicates  reference  to  the  ramie  and  not  to  what  we  now  know  as  linen. 
In  such  poems  as  the  Ramazana  and  the  Kalidassa  there  are  frequent 
references  to  be  found  to  the  plant  and  the  fiber  and  the  corresponding 

1  For  detailed  descriptions  of  the  methods  employed  in  China  and  India  for  the 
lireparation  of  ramie,  see  Three  Years  in  Western  China,  by  Sir  Alex.  Hosie;  also  The 
Journal  of  the  Agricultural  and  Horticultural  Society  of  India,  vol.  9,  part  1,  Calcutta, 
1891,  and  recent  issues  of  Indian  Industries  and  Power. 


782  JUTE,   RAMIE  AND   HEMP 

fabrics  made  therefrom,  which  are  no  doubt  the  ancient  ramie.  The  early- 
peoples  of  southern  Russia  carried  on  the  knowledge  of  ramie,  probably- 
deriving  it  from  the  peoples  of  the  Himalayan  districts.  Anyway,  accord- 
ing to  the  Chronicles  of  Nestor  (written  about  A.D.  904)  the  sails  of  the 
ships  on  the  Volga  were  made  of  ramie  or  China  grass. 

The  French  have  long  shown  a  special  interest  in  the  development  of 
ramie  as  a  textile  fiber  in  Europe,  and  they  have  been  very  energetic  in 
cultivating  the  plant  in  their  various  colonies.  The  proper  development 
of  its  use,  however,  as  a  textile  fiber  has  not  been  commensurate  with  its 
esteemed  and  valuable  qualities,  and  this  has  been  due,  as  before  indicated, 
to  the  impossibility  so  far  of  cheaply  and  efficiently  obtaining  the  fiber 
from  the  plant,  in  other  words  of  decorticating  it. 

In  Europe  attempts  have  been  made  to  decorticate  ramie  by  mechanical 
means.  A  rather  successful  process  of  this  type  is  described  by  Glafey,^ 
the  machine  being  constructed  by  H.  Boeken  &  Co.,  Diiren,  Germany. 
In  the  method  of  Fremy  and  Urbain  the  ramie  stalks  are  softened  by 
treatment  with  a  boiling  dilute  caustic  soda  solution,  after  which  they 
are  heated  for  four  hours  in  iron  cylinders  under  pressure  with  a  solution 
of  soda  ash  and  caustic  soda,  then  washed  and  soured  several  times. 
Other  similar  processes  have  also  been  described  using  sodium  silicate, 
phosphate  or  borate  in  order  to  give  the  fiber  a  finer  appearance  (Girard) ; 
also  treatment  with  salts  of  manganic  acid  have  been  suggested  ;2  also 
boiling  with  a  borax  emulsion  of  linseed  oil,  mineral  oil,  and  turpentine 
(Maclvor  and  Chester).  Other  methods  have  tried  the  use  of  an  alkali 
boil,  washing,  souring,  then  treatment  with  oxidising  agents  such  as 
potassium  permanganate,  chlorine,  hydrogen  peroxide.^  Also  the  arti- 
ficial retting  process  of  Bauer  ^  has  been  used  for  ramie,  and  also  the 
cold  bleaching  process  of  Pick  and  Erban.^  In  the  process  of  Harris  ^ 
the  ramie  stalks  are  impregnated  with  a  1  percent  solution  of  caustic  soda, 
steamed  for  six  hours,  washed  to  remove  the  dissolved  gums,  then  im- 
pregnated with  a  2  percent  solution  of  common  salt,  or  a  solution  of  soap, 
caustic  soda  and  linseed  oil,  and  steamed  again  under  pressure,  washed 
and  then  treated  with  the  simultaneous  or  alternate  action  of  ozone 
and  steam  in  a  closed  vessel.  This  is  said  to  accomplish  a  bleaching  and 
purification  of  the  fiber  in  a  few  hours.  For  the  cleaning  of  the  fiber  from 
the  decomposed .  tissues  mechanical  treatments  such  as  passing  through 
fluted  rolls  (breaking),  combing,  etc.,  are  required.    Blachon  and  Peret- 

^  Die  Rohstoffe  der  Textilindustrie,  p.  67. 
^  Societe  de  la  ramie. 

3  Boyle,  Bilderbeck,  Comess,  etc. 

4  Ger.  Pats.  68,807  and  80,023. 
6  Bnt.  Pat.  3259  of  1904. 

6  Ger.  Pat.  193,499;  see  Jahresbericht,  1907,  p.  407. 


PREPARATION  OF  RAMIE  783 

mere  ^  use  hypochlorite  of  soda  sokitions  for  isolating  the  ramie  fiber; 
Fuchs  2  uses  sulfite  liquors  at  100°  to  110°  C;  and  Pellmann  ^ 
treats  the  ramie  with  baths  of  caustic  soda  containing  soap  and 
alcohol. 

Many  of  the  processes  which  have  been  suggested  for  the  retting  of 
flax,  jute,  and  hemp  have  also  been  used  in  connection  with  ramie.  In 
the  process  of  Blackmore,'*  for  instance,  the  raw  fiber  is  heated  with  a  10 
percent  solution  of  sodium  aluminate  at  about  95°  C.  in  a  special  form 
of  kier,  which  is  then  closed  and  evacuated  to  better  remove  the  lye. 
After  the  addition  of  fresh  sodium  aluminate  the  material  is  heated  to 
4  atmospheres.  Washing  with  warm  water  follows  and  then  a  treatment 
with  carbonic  acid  at  7  atmospheres  pressure,  which  opens  up  the  fiber 
After  thorough  washing  and  a  subsequent  treatment  with  boiling  caustic 
soda  and  washing  the  decortication  is  completed.^ 

Much  has  been  written  in  the  technical  press  concerning  the  vast 
possibilities  of  ramie  as  a  textile  fiber.  According  to  Roux,  however, 
the  cost  of  its  production  will  always  prevent  its  common  use  for  the 
textiles  that  can  be  more  cheaply  grown  and  prepared.  While  it  has 
brilliancy  it  has  not  the  elasticity  of  wool  and  silk,  nor  the  flexibility  of 
cotton;  but  it  will  always  be  preferred  for  making  articles  requiring  the 
strength  to  resist  the  wear  and  tear  of  washing  and  exposure  to  weather. 
The  facility  with  which  it  may  be  made  to  imitate  other  textiles,  according 
to  Dodge,  is  one  of  the  principal  causes  which  has  kept  back  the  devel- 
opment of  the  ramie  industry.  The  folly  of  building  up  the  industry 
on  a  basis  of  imitating  something  else  is  to  be  deprecated ;  the  fiber  should 
be  used  in  those  articles  of  common  necessity  which  would  appear  on  the 
market  as  ramie,  so  that  any  distinctive  merit  the  textile  may  possess 
may  become  known,  not  only  to  the  ramie  trade,  but  to  the  consumers 
of  the  product.*^ 

According  to  Nodin  and  Brettoneau,  the  average  composition  of 
ramie  stalks,  after  degumming  and  drying,  is  as  follows : 

'Ger.  Prt/.  207,362. 
■  ^Momdsch.  Textil.,  1909,  p.  337. 

'  Ger.  Pal.  204,334. 

*  U.S.  Pal.  786,721. 

5  See  Faerber-Zeil.,  1905,  p.  191. 

^  Ramie  yarns  are  successfully  spun  on  a  large  scale  at  Baumgarten's  mill  (Erste 
Deutsche  Ramie  Gesellschaft)  at  Emmendingen,  Germany.  This  factory  is  sub- 
sidised by  the  German  Government  and  has  the  advantage  of  cheap  labor.  A  con- 
siderable quantity  of  ramie  yarn  from  this  mill  is  sent  to  the  United  States,  where 
it  is  chiefly  used  for  the  making  of  incandescent  gas  mantles.  In  the  United  States 
there  are  two  mills  producing  ramie  yarn  with  more  or  less  apparent  success  (1913); 
these  are  the  Springdale  Fiber  Co.  at  Canton,  Mass.,  and  the  Superior  Thread  and 
Yarn  Co.  at  Pluckamin,  N.  J. 


784  JUTE,   RAMIE   AND   HEMP 

Percent. 

Fiber 30 

Wood 55 

Bark,  etc 15 

The  following  is  an  analysis  of  ramie  ribbons : 

Percent. 

Ash 1 .  75 

Nitrogen 1 .  28 

The  ash  from  the  above  contained  the  following  constituents: 

Percent. 

Potash 32 .  57 

Soda S .  01 

Lime 22. G6 

Magnesia 1 1 .  33 

Phosphoric  acid 12 .  57 

Sulfuric  acid 3 .  9G 

Chlorine 2.98 

Silica 6.27 

On  French  authority  it  is  stated  that  the  yield  of  decorticated  fiber 
from  the  green,  unstrippcd  stalks  amounts  to  about  2  percent,  and  of 
degummed  fiber  about  1  percent.  Based  on  the  weight  of  dry,  stiipped 
stalks,  the  yield  of  the  degummed  fiber  would  be  about  10  percent. 

The  bast  of  the  ramie  cannot  be  removed  from  the  woody  tissue  in 
which  it  is  imbedded  by  a  simple  retting,  as  in  the  case  of  flax  and  other 
bast  fibers.  It  must  undergo  a  severe  mechanical  treatment,  whereby 
the  outer  bark  is  removed.  The  long,  fibrous  tissue  so  obtained  consists 
of  the  ramie  filaments  held  together  in  the  form  of  a  ribbon  b}^  a  large 
quantity  of  gum,  and  before  the  fibers  can  be  combed  out  this  gum  must 
be  removed  by  chemical  treatment.  The  gummy  matters  seem  to  con- 
sist essentially  of  pectose,  cutose,  and  vasculose.  In  the  degumming, 
the  object  is  to  remove  these  substances  without  affecting  the  cellulose 
of  the  fiber  proper.  The  vasculose  and  cutose  may  be  dissolved  by  treat- 
ment with  soap  or  caustic  alkalies  employed  under  pressure.  The  adher- 
ing pectose  can  then  be  detached  mechanically  by  washing. 

The  chief  difficulty  in  preparing  decorticated  ramie  for  spinning  is  the 
elimination  of  the  gum  which  holds  the  fibers  together.  Many  researches 
have  been  conducted  with  a  view  of  discovering  a  suitable  and  efficient 
process  of  degumming.  Previous  to  1914  a  considerable  degree  of  success 
had  been  attained  at  Emmendingen  in  Germany,  where  large  quantities 
of  ramie  yarn  were  produced.  A  bacterial  system  of  degumming  ramie 
has  been  announced  by  Prof.  Rossi  of  Naples,  the  results  of  which  are 


USES  OF  RAMIE  FIBER  785 

said  to  be  very  satisfactory.  When  the  fiber  is  properly  degummed  there 
is  no  particular  trouble  in  the  spinning  of  ramie.^ 

13.  Uses  of  Ramie  Fiber. — Though  ramie  has  many  excellent  qualities 
to  recommend  it  as  a  textile  fiber  for  definite  uses,  nevertheless  it  lacks 
the  elasticity  of  wool  and  silk  and  the  flexibility  of  cotton.^  As  a  result 
it  yields  a  harsher  fabric,  which  has  not  the  softness  of  cotton.  Owing 
to  its  smooth  and  regular  surface,  it  is  difficult  to  spin  to  fine  counts,  as 
the  fibers  lack  cohesion  and  will  not  adhere  well  to  each  other.  The 
ramie  fiber  also  resists  the  action  of  chemicals  perhaps  better  than  any 
other  vegetable  fiber;  it  has  a  high  luster,  being  more  glossy  than  jute; 
it  is  also  firmer  in  quality  than  hemp.  The  specific  gravity  of  ramie 
yarn  is  less  than  that  of  linen  in  about  the  ratio  of  6  to  10;  on  the  other 
hand  ramie  yarn  is  denser  than  cotton  in  the  ratio  of  about  6  to  5. 

One  of  the  principal  uses  of  the  ramie  fiber  at  present  is  for  the  making 
of  yarns  used  in  the  manufacture  of  gas-mantle  fabric,  for  which  it  is  the 
most  suitable  material  yet  found,  giving  stronger  and  more  resilient 
mantles  than  any  other  material.^  Its  chief  competitor  in  this  respect 
is  artificial  silk.  Ramie  is  also  used  to  some  extent  for  making  fishing 
nets  and  for  knit  underwear.  As  its  absorbent  properties  are  excellent, 
it  should  be  suitable  for  the  manufacture  of  surgical  bandages  and  hospital 
gauze.  It  has  been  suggested  as  a  substitute  for  linen,  but  as  cloth  made 
from  ramie  tends  to  crack  when  folded  it  would  not  be  a  suitable  sub- 
stitute in  linen  collars  and  cuffs,  and  it  is  also  doubtful  if  it  would  wear 
well  in  tablecloths,  sheets  and  similar  articles. 

Ramie  in  the  form  of  combed  silver  glued  into  a  coherent  web  is  also 
extensively  employed  as  material  for  hat  braids  and  trimmings.  To  be 
made  into  this  form  the  ramie  fiber  is  well  combed  so  as  to  parallel  the 
fibers  in  a  thin  and  uniform  web.  This  web  is  wound  on  a  suitable  roller, 
and  then  run  through  a  machine  provided  with  an  endless  apron  (made  of 
polished  white  metal  or  copper),  so  that  a  solution  of  gelatine  (100  parts 
of  gelatine  and  275  parts  of  water)  is  applied  to  both  sides  of  the  web. 

1  According  to  the  process  used  by  the  Ramie-Spmnerei  Emmendingen  {Ger.  Pat. 
115,745)  the  ferment  material  is  made  from  ramie  waste;  the  ferment  is  allowed  to  act 
for  several  days,  after  which  the  material  is  boUed  for  three  hours  at  2  atmospheres 
pressure  with  dilute  caustic  soda  solution,  washed,  squeezed  and  dried,  and  then 
further  purified  by  mechanical  means  to  make  the  fiber  ready  for  spinning.  It  is  said 
that  the  cost  of  the  process  amounts  to  less  than  I  cent  per  pound  of  ramie  fiber.  The 
process,  however,  gives  rise  to  such  a  stench  and  creates  such  a  nuisance  that  it  would 
hardly  be  tolerated  in  American  practice. 

2  The  price  for  raw  decorticated  ramie  in  England  for  1920  was  £120  to  £150  per 
ton,  as  compared  with  prices  in  1914  of  £40  to  £80. 

'  For  this  latter  purpose  it  appears  to  be  especially  adapted,  as  it  readily  absorbs 
the  solutions  of  metallic  salts  (cerium  and  thorium)  employed  for  this  purpose,  and 
after  ignition  it  leaves  an  ash  skeleton  or  mantle  possessing  considerable  strength  and 
resiliency. 


786 


JUTE,   RAMIE   AND   HEMP 


After  passing  through  squeeze  rolls  the  web  is  carried  through  a  drying 
chamber.^  To  prevent  the  gummed  web  from  sticking  to  the  metal 
apron,  the  latter  is  coated  by  means  of  a  spray  with  a  solution  of  8  parts 
of  white  wax  in  100  parts  of  turpentine.  The  gummed  web  is  next  cut 
into  strips  of  the  desired  width.  In  order  to  waterproof  the  web  and  then 
prevent  the  strips  from  disintegrating  when  dyed,  the  strips  are  hung  in  a 
closed  chamber  and  treated  with  the  vapor  of  formic  acid.     Treatment 


Fig.  312. — Ramie  Fiber.     (X350.)     L,  Lumen;    G,  granular  matter  in  lumen;   5,  long 
shreds  of  matter  in  lumen;    A',   knots  in  fiber.     (Micrograph  by  author.) 


with  solutions  of  chrome  or  tannin  might  also  be  employed  for  the  same 
purpose. 

In  order  to  make  the  gelatine  solution  more  transparent,  from  5  to  10 
percent  of  alcohol  may  be  added.  Collodion,  gums,  varnishes,  and  other 
substances  may  also  be  employed  to  produce  different  effects. 

14.  Microscopy  of  Ramie. — Microscopically  the  ramie  fiber  is  remark- 
able for  the  large  size  of  its  bast-cells.  These  are  from  60  to  250  mm.  in 
length  and  up  to  80  microns  in  width.  The  diameter  of  the  fiber  is  also 
characteristically  imeven,  sometimes  narrow  with  heavy  cell-walls  and 
well-defined  lumen  and  at  other  times  broad  and  flat  with  an  indistinct 

1  For  description  of  a  machine  for  applying  the  gelatine  solution,  see  Textile  World 
Record,  1913,  p.  594. 


MICROSCOPY  OF  RAMIE 


787 


m 


lumen,  but  showing 
heavy  striations  along 
the  fiber.^  The  ratio 
of  the  length  of  the 
fiber  to  its  breadth  is 
about  1  :  2400.  The 
fiber  consists  of  pure 
cellulose  with  no  indi- 
cation of  the  presence 
of  any  lignin  as  iodine 
and  sulfuric  acid  give 
a  pure  blue  stain,  and 

anihne  sulfate  gives  no  FirilS.-Ramie  Fiber,    a,  Sections;  b,  longitudinal  view; 

color.     In  an  ammo-  c,  ends,     (Cross  and  Bevan.) 

niacal  solution  of  cop- 
per oxide  ramie  becomes  great- 
ly swollen,  but  does  not  dis 
solve.  The  ramie  fiber  gives 
a  blue  coloration  with  the 
chlor-iodide  of  zinc  reagent, 
and  rose-red  with  chlor-iodide 
of  calcium;  white  ramie  gives 
no  coloration  with  aniline  sul- 
fate, but  greeyi  ramie  gives  a 
slight  yellow  color,  which  seems 
to  indicate  a  slight  degree  of 
lignification  in  the  case  of  the 
latter  fiber.  Along  the  fiber, 
joints  and  transverse  fissures 
are  of  frequent  occurrence 
(Fig.  312).  The  lumen  is 
especially  broad  and  easily 
noticeable.     The  ends  of  the 

fiber  elements  have  a  thick- 

FiG.  314. — Ramie  Fiber,  v,  Swollen  displacements;         „    ,  ,    ,  .    ,  , 

„  ■  .  ■,  X-         walled,    rounded     pomt,    and 

r,  fissures;     e,  pomt   or  end;     q,  cross-sections;  '  *^         ' 


J,   lumen;    sch, 


the    lumen    is    reduced  to    a 
line.      At    places    the   lumen 


i,   inner  layers  of  fiber-wall; 
stratifications.     (Hohnel.) 
1  In  this  connection  Hassack  gives  the  following  figures : 

Fiber  Diameter  in  Mm. 

Ramie 9.04    to  0.06 

Linen 0.016 

Cotton 0.014  to  0.024 

Silk 0.009  to  0.024 

Ramie  is  also  distinguished  by  the  great  length  of  its  fiber,  the  individual  fibers 


788 


JUTE,    RAMIE    AND    HEMP 


appears  to  be  more  or  less  filled  with  granular  matter,  and  sometimes 
with  long  uneven  shreds  of  matter,  evidently  dried-up  albuminous 
matter.  The  cross-section  of  the  fiber  (Fig.  313)  shows  usually  only  a 
single  element  or  a  group  of  but  a  few  members.  The  cross-section  is  also 
quite  large,  and  is  elliptical  in  shape;  the  lumen  appears  open,  and  fre- 
quently contains  granular  matter.  The  cross-section  also  frequently 
shows  strong  evidence  of  stratification  (Fig.  314) .  The  fibers  are  frequently 
very  broad,  and  at  these  parts  are  flat  and  ribbonlike  in  form,  but  are  never 
twisted. 


Fig.  315. — Ramie  Fibers  Stained  with  Iodine  and  Sulfuric  Acid.     (Herzog.) 


Miiller  gives  the  following  analysis  of  the  raw  fiber  of  samples  of  both 
China  grass  and  ramie : 


Constituent. 


Ash 

Water  (hygroscopic) 

Aqueous  extract 

Fat  and  wax 

CeUulose 

Intercellular  substances  and  pectin 


China  Grass, 

Ramie, 

Percent. 

Percent. 

2.87 

5.63 

9.05 

10.15 

6.47 

10.34 

0.21 

0.59 

78.07 

66.22 

6.10 

12.70 

being  usually  from  4  to  6  ins.  in  length,  though  they  may  at  times  reach  as  much  as 
10  to  16  ins.  This  is  rather  unusual  in  the  case  of  bast  fibers  which  are  generally 
made  up  of  rather  short  fiber  elements. 


COMMERCIAL  ASPECTS  OF  RAMIE 


789 


15.  Commercial  Aspect  of  Ramie. — The  amount  of  ramie  fiber  coming 
into  either  England  or  America  is  still  quite  insignificant  as  compared  with 


Fig.  316. — Ramie  Fiber  under  Polarised  Light.     (Herzog.) 

the  other  chief  textile  fibers.^     It  is  said  that  recently  ramie  is  being  used 
quite  extensively  in  the  Irish  linen  mills  to  blend  with  flax  in  spinning 

^  The  following  table  shows  the  amount  of  ramie  fiber  exported  from  China  during 
recent  years,  as  shown  by  the  customs  returns: 


Countries  of  Destination. 


France 

Great  Britain 

Hongkong 

Japan 

United  States  (including  Hawaii  and  the  Philippine  Islands) 
All  others 

Total 


1917. 
(Tons.) 


432 

1,265 

386 

14,958 

1,337 

84 


18,462 


1918. 
(Tons.) 


734 

1,445 

642 

13,658 

1,784 

45 


18,308 


1919. 

(Tons.) 


135 
295 
317 
13,096 
25 
194 


14,062 


1920. 
(Tons.) 


179 

1,309 

319 

10,303 

2 

356 


12,468 


Exports  of  ramie  or  grass  cloth  from  China  in  1917  were  valued  at  about  $2,000,000; 
in  1918,  at  $2,500,000;  and  in  1919,  at  $5,000,000.  The  following  table  shows  the 
quantity  and  destination  of  exports: 


Countries  of  Destination. 


Hongkong 

Japan 

Korea 

Phihppine  Islands . 
Straits  Settlements 
All  others 

Total 


1917. 

1918. 

1919. 

1920. 

(Tons.) 

(Tons.) 

(Tons.) 

(Tons.) 

101 

82 

82 

113 

68 

100 

135 

131 

820 

707 

1472 

1388 

2 

1 

3 

2 

61 

61 

.... 

57 

82 
10 

1052 

951 

1751 

1726 

Kiukiang  and  Swatow  are  the  original  points  of  export  of  two-thirds  of  the  entire 
amount  of  grass  cloth  exjjorted  from  China,  Chungking  and  Shanghai  making  a  distant 
third  and  fourth.  Two-thirds  of  the  grass  cloth  exported  from  all  China  is  sent  to 
Hankow,  Chinkiang  and  Shanghai,  where  it  supphes  the  re-export  trade  and  the 
demand  for  local  consumption. 


790 


JUTE,    RAMIE    AND    HEMP 


and  that  the  resultant  fabrics  are  of  the  most  desirable  quality,  being 
equal  to  the  best  Irish  linen  goods.  It  is  also  claimed  that  Italian  hemp  is 
being  used  in  the  same  connection. 

There  is  no  doubt  that  ramie  could  be  successfully  spun  into  yarns  of 
very  satisfactory  fineness  and  quality  if  a  sufficient  cheap  supply  of  the 
decorticated  and  degummed  "  filasse."  could  be  obtained.  The  objections 
heretofore  raised  in  most  quarters  to  the  spinning  of  ramie  fiber  have  been 
based  on  the  fact  that  the  machinery  employed  was  not  especially  designed 
for  the  treatment  of  this  fiber,  but  was  machinery  really  intended  for  other 
purposes — for  preparing  and  spinning  cotton,  wool,  or  linen.  If  the 
working  qualities  of  this  fiber  were  properly  studied  and  suitable  machinery 

were  designed  for  handling  it 
specifically,  there  would  be  no 
particular  difficulties  in  the 
preparation  of  fine  ramie 
yarns. 

One  fault  to  be  met  with 
in  some  qualities  of  ramie  is 
that  known  as  "  hard  ends," 
being  generally  fibers  that 
have  not  developed  to  their 
full  length,  but  have  grown 
thick  and  short,  or  two  or 
three  fibers  that  have  grown 
together.  In  a  satisfactory 
combing  process  these  hard 
ends  will  be  almost  wholly  re- 
moved from  the  slivers,  but 
if  they  are  not  completely 
gotten  rid  of  the  yarn  will 
exhibit  inequalities  and  the  resultant  cloth  will  have  a  speckled  appear- 
ance after  dyeing. 

It  has  also  been  suggested  to  cut  ramie  fiber  into  relatively  short 
lengths  similar  to  cotton,  then  wind  it  with  the  latter  fiber  and  spin  it 
into  yarns.  But  just  what  advantage  would  be  gained  by  this  is  difficult 
to  understand,  as  it  would  be  impairing  the  qualities  of  a  long  strong 
fiber  to  make  it  complete  with  cotton,  a  much  cheaper  material. 

16.  Hemp. — This  is  a  name  applied  to  a  large  number  of  bast  fibers 
more  or  less  analogous  in  appearance  and  properties.  Among  the  different 
varieties  of  hemp  appearing  in  trade  may  be  enumerated  the  following 
(Dodge) : 

Ambari  (or  brown)  hemp Hibiscus  cannahinus 

Bengal  (or  Bombay)  hemp Crotalaria  juncea 


Fig.  317.— Ramie  Fiber.  (X420.)  Showing  the 
longitudinal  ridges  and  knot-like  cross-markings. 
(Micrograph  by  author.) 


HEMP  791 

Black-fellow's  hemp Commersonia  fraseri 

Bowstring  hemp  (Africa) Sansevieria  guineensis 

Bowstring  hemp  (Florida) S.  longiflora 

Bowstring  hemp  (India) S.  roxburghiana 

Calcutta  hemp Jute 

Cebu  hemp Mii^a  textilis 

Colorado  River  hemp Sesbania  macrocarpa 

Cretan  hemp Datisca  cannabina 

Cuban  hemp Fourcroya  cubensis 

False  hemp  (American) Rhiis  typhina 

False  sisal  hemp Agave  decipiens 

Giant  hemp  (China) Cannabis  gigantea 

Hayti  hemp Agave  foetida 

Ife  hemp Sansevieria  cylindrica 

Indian  hemp Apocynum  cannabinum 

Jubbulpore  hemp  (Madras) Crotalaria  tenuifolia 

Manila  hemp Musa  iexlilis 

New  Zealand  hemp  (or  flax) Phormium  tenax 

Pangane  hemp Sansevieria  Mrkii 

Pita  hemp Yucca  sp. 

Pua  hemp  (India) Maoutia  puya 

Queensland  hemp Sida  retusa 

Rangoon  hemp Laportea  gigas 

Roselle  hemp Hibiscxis  sabdariffa 

Sisal  hemp Agave  rigida 

Sunn  hemp Crotalaria  juncea 

Swedish  hemp Urtica  dioca 

Tampico  hemp Agave  heteracantha 

Water  hemp Eupatoriurn  cannabinum 

Wild  hemp Maoutia  puya 

Hemp  proper,  or  the  so-called  common  hemj),  is  derived  from  the  bast 
of  Cannabis  sativa.  This  is  a  shrub  ^  growing  from  6  to  15  ft.  in  height, 
and  though  originally  a  native  of  India  and  Persia,  it  is  now  cultivated 
in  nearly  all  the  temperate  and  tropical  countries  of  the  world.  At  the 
present  time  it  is  quite  extensively  grown  in  America,^  though  not  as  yet 

1  The  hemp  is  an  annual  plant,  with  a  straight  stalk,  and  elongated,  highly  dentated 
leaves.  The  latter  have  a  narcotic  odor,  and  occur  in  bunches  of  three,  five,  or  seven. 
The  flower  is  without  petals  and  develops  into  the  well-known  hemp-seed  on  maturity. 
The  hemp  plant  is  dioecious;  that  is,  it  belongs  to  the  class  of  plants  in  which  the 
sexes  are  divided,  some  stems  bearing  only  clusters  of  male  flowers  (panicles),  while 
others  bear  only  female  flowers  (catkins).  The  female  plant  grows  from  6  to  8  ft. 
in  height,  while  the  male  plant  (fi7vhlc  hc7np)  is  shorter. 

^  Several  varieites  of  hemp  are  grown  in  this  coimtry,  that  cultivated  in  Kentucky 
and  having  a  hollow  stem  being  most  common.  China  hemp  and  Smyrna  hemp  are 
also  grown,  and  in  California,  Japanese  hemp  is  cultivated  and  gives  a  remarkably 
fine  product.  Five  varieties  of  hemp  appear  to  be  cultivated  in  Europe:  the  common 
hemp,  Bologne  hemp  (known  also  as  Piedmontese  hemp  or  great  hemp),  Chinese 
hemp,  small  hemp  (the  Caruipa  piccolo  of  Italy),  and  Arabian  hemp.  The  latter  is 
also  known  as  Takrousi  and  is  chiefly  cultivated  for  its  resinous  principle,  from  which 
hasheesh  is  obtained. 


792 


JUTE,   RAMIE  AND   HEMP 


Fig.  318.— Part  of  Cross-section  of  Hemp  Stalk.  B, 
Woody  tissue;  /,  secondary  layer  of  fibers;  F,  main 
layer  of  fibers.     (Le  Comte.) 

obtained.^  Japanese  hemp 
is  of  excellent  quality,  and 
appears  in  trade  in  the 
form  of  very  thin  ribbons, 
smooth  and  glossy,  of  a 
light  straw  color,  and  the 
frayed  ends  showing  a 
fiber  of  exceeding  fineness. 
Hemp  appears  to  have 
been  the  oldest  textile  fiber 
used  in  Japan. 

Italian  hemp  has  been 
suggested  as  a  possible 
substitute  for  linen  in  the 
preparation  of  fabrics.  It 
has  not  as  yet,  however, 
been  spun  to  a  very  fine 
thread,  though  in  Belgium 
it   has    been    successfully 


in  sufficient  amount  to  sat- 
isfy the  home  consumption. 
Russia  produced  an  enorm- 
ous quantity  of  hemp;  in 
fact,  this  fiber  formed  a 
staple  article  of  export  from 
that  country.  Poland  is  also 
a  large  producer.  French 
hemp,  though  not  grown  to 
such  an  extent,  is  much 
superior  in  quality  to  that 
from  either  Russia  or  Po- 
land, it  being  fine,  white, 
and  lustrous.  Italian  hemp 
is  also  of  a  very  high  grade. 
In  India  hemp  is  not  grown 
so  much  for  its  fiber  as 
for   the    narcotic    products 


Fig.  319.- 


Hemp  Fiber  from  Cannabis  sativa. 
(Herzog.) 

1  Hemp  grows  wild  throughout  Indian  but  it  is  regarded  as  the  source  of  the  drug 
known  as  bhang  or  hasheesh,  rather  than  as  a  fiber  plant.  Dodge  states  that  the 
use  of  hemp  among  the  ancients  was  very  limited;  it  is  not  mentioned  in  the  Scriptures 
and  is  rarely  referred  to  by  the  writers  of  antiquity.  It  was  apparently  used  by  the 
Scythians  at  least  as  early  as  500  B.C.,  and  some  writers  attribute  to  its  cultivation 
an  antiquity  more  remote  by  1000  years.  The  Romans  were  familiar  with  the  use 
of  hemp  for  the  making  of  sails  and  cordage,  though  not  until  after  the  Christian  era. 


PREPARATION  OF  HEMP  793 

spun  up  to  35  lea  on  a  commercial  scale.  Italian  hemp  is  at  present  used 
mostly  for  twine,  though  there  is  evidently  possibility  for  its  use  in  the 
making  of  finer  yarns.  The  chief  difficulty  in  the  spinning  of  hemp  is  that 
it  must  be  properly  softened  before  it  can  be  used,  and  it  can  be  a  satis- 
factory substitute  for  linen  only  when  the  softening  process  has  been  most 
thoroughly  carried  out.  Also,  on  account  of  its  lack  of  elasticity  Italian 
hemp  yarn  tends  to  break  when  used  as  a  warp,  even  when  blended  with 
flax. 

17.  Preparation  of  Hemp. — The  hemp  fiber  is  obtained  from  the  plant 
by  a  process  of  retting  similar  to  that  employed  for  flax  ^  the  plant  being 
passed  through  about  the  same  operations,  such  as  rippling,  retting,  break- 
ing and  heckling.  The  broken  hemp  is  known  as  bast  hemp,  and  the  heckled 
as  pure  hemp.  The  latter  is  separated  into  shoemaker's  and  spinning  hemp. 
The  tow  separated  in  hackling  is  used  for  stuffing  in  upholstery.  The 
method  of  dew-retting  is  chiefly  used;  that  is,  the  stalks  are  spread  out 
in  the  fields  until  the  action  of  the  elements  causes  the  woody  tissue  and 
gums  enclosing  the  fibers  to  decompose.  Retting  in  pools  of  water  has 
been  practised  to  a  slight  extent,  but  evidently  not  with  much  success.^ 
It  is  said  that  100  parts  of  raw  hemp  furnish  25  parts  of  raw  fiber  or  filasse ; 
and  100  parts  of  the  latter  yield  65  parts  of  combed  filasse  and  32  parts 
of  tow. 

Hemp  fiber,  prepared  by  water-retting  as  practised  in  Italy ,^  is  of  a 
creamy-white  color,  lustrous,  soft,  and  pliable.  It  makes  a  satisfactory 
substitute  for  flax,  and  is  used  for  medium  grades  of  nearly  all  classes  of 
goods  commonly  made  from  flax,  except  the  finer  linens.  When  prepared 
by  dew-retting,  as  practised  in  this  country,  the  fiber  is  gray,  and  some- 
what harsh  to  the  touch.  It  is  used  for  yacht  cordage,  ropes,  fishing- 
lines,  linen  crash,  homespuns,  hemp  carpets,  and  as  warp  in  making  all 
kinds  of  carpets  and  rugs. 

The  commercial  fiber  is  pearly  gray,  yellowish  or  greenish  to  brown 
in  color,  and  from  40  to  80  ins.  in  length.  Its  fineness  of  staple  is  less 
than  that  of  linen,  though  its  tensile  strength  is  appreciably  greater. 
The  best  quahties  of  hemp  are  very  light  in  color  and  possess  a  high  luster 
almost  equal  to  that  of  linen.  The  annual  production  of  hemp  fiber  is 
about  600,000,000  lbs. 

Spanish  hemp,  of  which  there  is  a  very  large  crop,  is  irregular  and 
unreliable;    it  is  practically  the  same  fiber  as  Italian  hemp,  but  it  is  of 

^  The  plant  is  ready  for  pulling  when  the  lower  leaves  become  limp  and  the  tip 
of  the  stalk  turns  yellowish.  The  male  plants  are  pulled  first  and  the  female  plants 
about  2  to  3  weeks  later. 

2  Baden  hejiip,  which  is  a  much-prized  variety,  is  prepared  by  stripping  the  bast 
from  the  retted  stalks  by  hand.     The  product  is  entirely  free  from  shives. 

5  The  total  crop  of  hemp  fiber  in  Italy  for  1920  amounted  to  about  100,000  tons. 


794 


JUTE,    RAMIE   AND   HEMP 


inferior  quality.  Hungarian 
hemp  is  of  better  quality  and 
some  ranks  equal  to  the  Italian 
fiber;  Russian  hemp  is  also  of 
the  same  general  character. 

The  seed  of  the  hemp 
plant,  like  that  from  flax,  is 
also  utilised  for  the  oil  it  con- 
tains;^ 100  parts  of  seed  fur- 
nish 27  parts  of  oil.  So  this 
forms  an  extensive  and  im- 
portant by-product  in  the  cul- 
tivation of  hemp. 

18.  Microscopy  of   Hemp. 

— Under  the    microscope  the 

Fig.  320.— Fibers  of    Hemp.     (X300.)     Showing    hg^p  fiber  is  seen   to  consist 

longitudinal  fissures  and  transverse  cracks  and    ^^  ^^j^  elements  which  are  un- 

iointed-like  structure.     (Micrograph  by  author.)  •  u      j- 

•"  usually  long,  averagmg  about 


Fig.  321.— Hemp  Fibers.     (X300.) 


L,  Lumen;    /,  joint-like  structure, 
by  author.) 


(Micrograph 


1  Hemp  seed  yields  a  greenish  colored  oil  having  a  peculiar  odor.  It  is  used  in  the 
making  of  green  soap  for  the  preparation  of  artist's  colors  and  varnishes,  and  in  some 
localities  for  the  making  of  oil-gas.  Hemp  seed  is  also  used  as  a  bird  food,  and  in 
some  countries  (Russia)  is  an  article  of  diet. 


MICROSCOPY   OF   HEMP 


795 


Fig.  322.— Hemp  Fibers. 
a,  cross-sections 


b,  Longitudinal  views;  c, 
(Cross  and  Bevan.) 


20  mm.  in  length,  but  varying  from  5  to  55  mm.  The  diameter,  however, 
is  very  small,  av- 
eraging 22  microns 
and  varying  from 
16  to  50  microns. 
Hence  the  ratio 
between  the  length 
and  diameter  is 
about  1000.  The 
fiber  is  rather  un- 
even in  its  diam- 
eter, .and  has 
occasional  attach- 
ments of  fragment- 
ary parenchymous 
tissue.  In  its 
linear  structure 
the  fiber  exhibits 

frequent   joints,  longitudinal  fractures,    and   swollen  fissures  (Fig.  320). 

The  lumen  is  usu- 
ally broad,  but  to- 
ward the  end  of  the 
fiber  it  becomes  like 
aline  (Fig.  321).  It 
shows  scarcely  any 
contents.  The  ends 
of  the  filaments  are 
blunt  and  very 
thick- walled,  and 
often  possess  lateral 
branches.^  The 
cross-section  gener- 
ally shows  a  group 
of  cells  which 
nearly  always  have 
rounded  edges  and 
are  not  so  sharp- 
angled  and  polyg- 
onal as  in  the  case 
Fig.  323. — Hemp  Fibers.     (X300.)     (Micrograph  by  author.)    ^^    j^^^    /p-       ^22) 

There  is  also  a  median  layer  between  the  cells,  which  is  evidenced  by  it 

*  Forked  ends  are  very  characteristic  of  hemp  fibers,  but  such  a  condition  is  never 
observed  with  flax. 


796 


JUTE,   RAMIE  AND  HEMP 


turning  yellow  on  treatment  with  iodine  and  sulfuric  acid.  In  the  section 
the  lumen  appears  irregular  and  flattened,  and  does  not  show  any 
contents.  The  cell-walls  frequently  exhibit  a  remarkable  stratification, 
the  different  layers  yielding  a  variety  of  colors  on  treatment  with  iodine 
and  sulfuric  acid. 

The  intercellular  (median  layer)  matter  which  binds  the  elements  of 
the  hemp  together  contains  vasculose,  and  even  the  cellulose  of  the  fiber 

itself  appears  to  be  impregnated 
with  this  substance.  This  is  the 
cause  of  the  stratified  appearance 
of  the  cell-wall  when  the  fiber  is 
treated  with  the  iodine-sulfuric  acid 
reagent.  When  the  hemp  fiber  is 
viewed  longitudinally  and  is  treated 
with  the  above  reagent,  a  green 
color  is  obtained,  due  to  the  mixing 
of  the  yellow  of  the  vasculose  layer 
and  the  blue  of  the  cellulose  layer. 
By  this  means  hemp  may  readily  be 
distinguished  from  linen,  which  gives 
a  characteristic  blue  color. 

When  examined  under  polarised 
light,  hemp  shows  very  bright  colors 
similar  to  linen  and  ramie.  Hemp 
also  gives  the  following  microchemi- 
cal  reactions:  (a)  with  iodine-sul- 
furic acid  reagent,  bluish  green 
coloration;  (b)  with  chlor-iodide  of 
zinc,  blue  or  violet,  with  traces  of 
yellow;  (c)  chlor-iodide  of  calcium, 
rose  red  with  traces  of  yellow;  (d) 
aniline  sulfate,  yellowish  green  color- 
ation; (e)  ammoniacal  fuchsine 
solution,  pale-red  coloration;  (/) 
with  Schweitzer's  reagent  the  hemp  fibers  swell  irregularly  with  a 
characteristic  appearance  (Fig.  324)  and  after  a  while  dissolve  almost 
completely,  leaving  only  the  fragments  of  parenchymous  tissue. 

Hemp  is  sometimes  difficult  to  distinguish  microscopically  from  flax; 
but  the  two  may  readily  be  told  by  an  examination  of  the  ends  of  the 
fibers,  hemp  nearly  always  exhibiting  specimens  of  forked  ends,  whereas 
flax  never  has  this  peculiarity.  The  fibers  of  hemp  are  also  less  transparent 
than  those  of  linen,  and  the  interior  canal  is  often  more  difficult  to  distin- 
guish, on  account  of  the  numerous  striations  on  the  surface.     The  difference 


Fig.  324. — Hemp  Fibers  Treated  with 
Schweitzer's  Reagent.  A,  Strongl.y  lig- 
nified  fiber;  B,  fiber  free  from  ligneous 
matter;  i,  i,  skin  of  inner  canal;  a,  ex- 
ternalligneous  tissue;  .s,  swollen  cellulose. 
(Wiesner.) 


MICROSCOPY  OF  HEMP  797 

in  the  appearance  of  the  cross-sections  is  also  of  service  in  discriminating 
between  these  two  fibers.  Again,  the  parenchymous  tissue  which  fre- 
quently occurs  as  attached  fragments  to  hemp  fibers  is  rich  in  star-shaped 
crystals  of  calcium  oxalate,  and  this  is  scarcely  ever  to  be  noticed  in  the 
case  of  flax.  A  peculiarity  to  be  noticed  in  the  examination  of  hemp  is 
the  occasional  presence  of  long  narrow  cells  filled  with  reddish  brown 
matter,  insoluble  in  the  ordinary  solvents.  These  cells  occur  between 
the  fibers  as  well  as  in  the  bast,  and  probably  contain  tannin.  They  are 
not  to  be  found  in  flax.  The  behavior  of  isolated  hemp  cells  with  ammo- 
niacal  copper  oxide  solution  is  also  quite  characteristic;  the  cell  mem- 
brane acquires  a  blue  to  a  bluish  green  color,  and  swells  up  like  a  blister, 
showing    sharply    defined    longitudinal    striations.     The    inner    cell-wall 


^**=%?^^^- 


Fig.  325. — Hemp  Fibers  Treated  with  Schweitzer's  Reagent.     (Herzog.) 

remains  intact  in  the  form  of  a  spirally  wound  tube  contained  inside  the 
strongly  swollen  mass  of  the  fiber. 

The  hemp  fiber  is  not  composed  entirely  of  pure  cellulose,  as  it  gives 
a  yellow  to  yellowish  green  coloration  with  aniline  sulfate,  and  a  greenish 
color  with  iodine  and  sulfuric  acid.  Both  hydrochloric  acid  and  caustic 
potash  give  a  brown  coloration,  while  ammonia  produces  a  faint  violet. 
It  appears  to  be  a  mixture  of  cellulose  and  bastose.  Bleached  hemp, 
however,  shows  the  reactions  of  pure  cellulose.  Miiller  gives  the  following 
analysis  of  a  sample  of  the  best  Italian  hemp: 

Percent. 

Ash 0. 82 

Water  (hygroscopic) 8 .  88 

Aqueous  extract 3 .  48 

Fat  and  wax 0 .  56 

Celhilose 77.77 

IntercelUilar  matter  and  pectin  bodies 9.31 


798  JUTE,    RAMIE   AND   HEMP 

It  is  claimed  ^  that  hemp  may  be  mercerised  by  soaking  the  fiber  for 
several  hours  in  a  vat  containing  caustic  soda  solution  of  10°  to  30°  Be. 
then  hydroextracting,  washing  in  dilute  soap  solution,  acidifying  with 
hydrochloric  or  acetic  acid  and  washing  again.  The  hemp  is  said  to 
acquire  a  softer  feel,  and  becomes  curly,  clear,  and  silky  in  appearance. 

19.  Properties  and  Uses  of  Hemp. — Hemp  appears  to  contain  more 
hygroscopic  moisture  than  cotton  or  linen.  Samples  examined  by  the 
author  contained  8  percent  moisture  compared  with  6  percent  for  cotton 
under  the  same  conditions.  At  the  RoubaLx  conditioning  house  the 
regain  allowed  on  hemp  is  12  percent,  and  this  same  figure  was  fixed  by 
the  International  Congress  at  Turin. 

Hemp  is  principally  employed  for  the  manufacture  of  twine  and 
cordage,  for  which  its  great  strength  eminently  adapts  it;  and,  besides, 
it  is  a  very  durable  fiber,  and  is  not  rotted  by  water.  In  this  respect  it 
differs  very  essentially  from  jute.  Ordinary  hemp  is  seldom  used,  however, 
for  woven  textiles,  as  it  is  harsh  and  stiff,  and  not  sufficiently  pliable  and 
elastic.  It  also  possesses  a  rather  dark-brown  color,  and  cannot  be  suc- 
cessfully bleached  without  serious  injury  to  the  quality  of  the  fiber. 

20.  Cuban  Hemp. — Cuban  hemp  of  trade  is  the  fiber  from  Fourcroya 
cubensis,  a  plant  native  to  tropical  America,  and  having  long  leaves  in 
which  the  fiber  is  found.  The  fiber  is  of  very  good  quality  and  is  similar 
to  sisal  hemp.  Another  species,  the  F.  gigantea,  or  giant  lily,  also  gives  a 
good  fiber  which  closely  resembles  sisal  hemp  and  no  doubt  is  often  sold  in 
trade  for  this  latter  fiber.  It  is  also  grown  in  tropical  America,  and  the 
fiber  is  called  by  the  natives  fique,  and  is  principally  employed  for  the 
making  of  bagging,  horse  blankets,  etc.  It  is  known  in  Venezuela  as 
cocuiza. 

21.  Sunn  Hemp  is  the  bast  fiber  of  the  Crotalaria  juncea;  it  is  also 
known  by  the  names  of  Conkanee,  Indian,  Brown,  and  Madras  hemp. 
It  grows  abundantly  in  the  countries  of  southern  Asia,  and  is  largely 
used  in  the  manufacture  of  cordage.  It  appears  to  have  been  one  of  the 
earliest  fibers  mentioned  in  Sanscrit  literature.  It  was  known  in  the 
Institutes  of  Manu  under  the  name  of  sana.'^  This  hemp  was  also  probably 
known  to  the  Chinese  at  a  very  remote  date.  The  fiber  is  obtained  from 
the  plant  by  a  system  of  retting  very  similar  to  that  of  flax. 

True  Indian  hemp  is  the  bast  fiber  from  Apocynum  cannahinum;  this 
fiber  is  a  light  cinnamon  in  color  and  is  long  and  tenacious.  It  was  prin- 
cipally employed  by  the  North  American  Indians,  who  made  bags,  mats, 
belts,  and  cordage  from  it.     Spon  mentions  Indian  hemp  under  the  com- 

1  Fr.  Pat.  510,52.5. 

^  The  term  sana  is  supposed  by  some  authorities  to  refer  to  sunn  hemp,  though 
Dr.  Watt  seems  to  be  of  the  opinion  that  the  term  designated  a  group  of  fibers,  sunn, 
sanpat,  or  Hibiscus  cannabinus,  and  common  hemp,  Cannabis  saliva.  Dodge,  how- 
ever, thinks  that  the  evidence  is  in  favor  of  sunn  hemp  alone. 


SUNN  HEMP 


799 


mon  name  of  "  Colorado  hemp,"  but  this  latter  name  really  belongs 
to  the  fiber  from  Seshania  inacrocarpa.  To  the  same  family  (Papilionacece) 
as  sunn  hemp  belong  two  other  species 
of  plants  which  yield  valuable  fibers 
for  paper  manufacture — namely,  Span- 
ish broom  (spartium  junceum)  and 
German  broom  {Spariium  scoparium) . 

Another  fiber  of  India  resembling 
sunn  hemp  is  known  as  Devil's  cotton 
(Abroma  augusta).  The  plant  yields 
three  crops  a  year  and  is  more  easily 
cultivated  than  jute  or  sunn  hemp. 
The  fiber  is  from  the  bast  of  the  twigs, 
and  is  strong,  white,  and  clean,  and 
much  valued  for  local  uses.  Watt 
states  that  it  might  be  employed  as 
a  substitute  for  silk,  therefore  it  is 
probable  that  the  fiber  has  a  high 
degree  of  luster.  According  to  Royle, 
a  cord  of  this  fiber  bore  74  lbs.  against 
a  similar  cord  of  sunn  hemp  that  broke 
with  68  lbs.  It  is  chiefly  employed 
locally  as  a  cordage  fiber.  The  fiber 
of  sunn  hemp  is  of  a  better  quality 
than  jute,  being  lighter  in  color,  of 
a  better  tensile  strength,  and  more 
durable  to  exposure.  Fig.  326.— Leaf  and  Blossom  of  Sunn  Hemp 

The  following  tables  of  comparative      (Crotalariajuncea).    (After  Bulletin  U.  S. 
tensile  strengths  for  various  cordage     Dept  Agric.) 
fibers  have  been  adopted  from  Royle's 

work  on  The  Fibrous  Plants  of  India;   the  tests  were  made  on  ropes  of 
the  same  size  and  1.2  meters  in  length. 

I.     COMPAKATIVE   STRENGTH,    DrY  AND   WeT 


Fiber. 


Hemp  from  Calcutta 

Sunn  hemp  (fresh  retted) 

' '  (retted  after  drying) 

Jute  {Corchorus  capsularis) 

' '     (C.  olilorius) 

' '     (C  stridus) 

Gambo  hemp  (Hibiscus  cannabinus) 

Roselle  hemp  {H.  sabdariffa) 

Hibiscus  abelmoschus 

Ramie  (Boehmerin  tenacissima) 


Dry,  Kilos. 

Wet,  Kilos. 

72 

86 

51 

72 

27 

35 

65 

66 

51 

56 

47 

52 

52 

60 

41 

53 

49 

49 

110 

126 

800 


JUTE,    RAMIE   AND   HEMP 


II.   Comparative  Strength  of  Prepared  Ropes,  and  after  Steeping  in 

Water  116  Days 


Fiber. 


Hemp,  English 

"       Calcutta. .  . . 

Coir 

Sunn  hemp 

Jute 

Linen,  Calcutta.  .  .  . 
Agave  americana. . . . 
Sanserieria  zeylanica 


Prepared  Ropes. 


Natural. 


47 
34 
39 
31 
31 
17 
50 
54 


Tanned .        Tarred 


63 

31 
31 

36 
33 


20 

27 
28 

35 
22 


Water- 
soaked. 
Natural. 


Rotted 

24 
Rotted 

18 
Rotted 

13 


Dr.  Wright  gives  the  following  table  for  the  strength  of  several  cordage 
fibers : 

Pounds. 

Sunn  hemp 407 

Cotton  rope 346 

Hemp 290 

Coir 224 


According  to  Roxburgh,  similar  lines  of  jute  and  sunn  hemp  showed  the 
following  comparative  tensile  strengths: 


Jute 

Sunn  hemp. 


Dry. 


143 
160 


Wet. 


146 
209 


In  appearance  sunn  hemp  is  very  similar  to  hemp,  both  to  the  naked 
eye  and  under  the  microscope.  The  raw  fiber  is  coarse,  flattened,  and 
dark  gray  in  color;  the  purified  fiber  is  yellowish  gray,  rather  lustrous,  and 
of  a  fine  texture. 

The  essential  distinction  between  sunn  hemp  and  hemp  is  in  the  cross- 
section  of  the  former  (Fig.  327),  which  shows  the  presence  of  a  very  thick 
median  layer  of  lignin  between  the  individual  cells.  The  lumen  in  the 
cross-section  is  also  usually  rather  thick,  and  often  contains  yellowish 
matter  differing  in  these  respects  from  hemp,  in  which  the  lumcni  is  fiat  and 
narrow  and  always  empty.  The  bast-cells  of  sunn  hemp  ai'e  13  to  50 
microns  broad,  and  in  longitudinal  view  are  partly  striated,  and  also 


SUNN   HEMP 


801 


show  dislocations  and  cross-marks.     The  ends  are  thickened  and  either 

bhmt  or  narrowed  with  warty  irregularities.     Iodine  and  strong  sulfuric 

acid  produce  a  peculiar  swelling  of  the  fiber,  the  outer  yellow  layer  becoming 

converted  into  a  yellow  mass  over  which  flows  the  blue  semi-liquid  mass 

of  cellulose,  leaving  as  a  residue 

a  greenish  yellow   inner   tube. 

With   iodine   and   sulfuric  acid 

sunn  hemp  gives  a  greenish  blue 

coloration,     and     with     chlor- 

iodide  of   zinc    brownish   blue. 

This  would   indicate   that   the 

fiber  is  of  rather  pure  cellulose, 

but  enveloped  with  a  layer  of 

lignified  tissue. 

Another  variety  of  Crotalaria 
used  for  its  fiber  is  the  C.  tenui- 
folia  from  which  is  obtained  the 
Jubbulpore  hemp.  This  fiber  is 
said  by  some  to  be  superior  to 
that  of  Russian  hemp  {Canna- 
bis saliva),  its  relative  tensile 
strength  being  95  lbs.  to  80  lbs. 
for  the  latter.  The  fiber  is  4 
to  5  ft.  in  length,  and  resembles 
the  best  Petrograd  hemp.  The 
fib.er  C.  retusa  is  also  to  be 
found  in  India  under  the  name 

of  sunn  hemp;   C.  sericea  and  C.  striata  are  other  species  which  are  also 
employed  for  fiber. 

M tiller  gives  the  following  analysis  of  raw  sunn  hemp: 

Percent. 

Ash 0.61 

Water  (hygroscopic) 9 .  60 

Aqueous  extract 2 .  82 

Fat  and  wax 0 .  55 

Cellulose 80.01 

Pectin  bodies 6 .  41 

According  to  Wiesner  sunn  hemp  contains  a  lower  percentage  of  mois- 
ture than  any  other  vegetable  fiber.  He  gives  the  amount  for  air-dried 
fiber  as  5.34  percent,  and  after  exposure  to  an  atmosphere  saturated  with 
steam  as  10.87  percent.  It  is  probable,  however,  that  after  being  stored 
for  some  time  the  fiber  of  sunn  hemp  will  show  a  higher  percentage  of 
moisture. 


Fig.  327.  Sunn  Hemp.  (X325.)  L,  View  of 
middle  portion;  v,  joints;  I,  lumen;  s,  pointed 
ends;  q,  cross-sections;  m,  outer  layer  of 
fiber;     i,   inner   layers.     (Hohnel.) 


802 


JUTE,   RAMIE   AND   HEMP 


22.  Ambari  or  Gambo  Hemp  is  an  East  Indian  fiber  derived  from  the 
bast  of  Hibiscus  cannabinus.  The  fiber  when  carefully  prepared  is  from 
5  to  6  ft.  in  length;  it  is  of  a  lighter  color  than  hemp,  and  harsher.  Its 
tensile  strength  is  somewhat  less  than  that  of  sunn  hemp.  Like  the 
latter  fiber,  it  is  principally  used  for  cordage,  though  it  is  also  employed  in 
India  for  the  manufacture  of  a  coarse  canvas.  In  its  microscopic  charac- 
teristics ambari  hemp  is  very  similar  to  jute;  the  length  of  the  fiber  ele- 
ments varies  from  2  to  6  mm. 
and  the  diameter  from  14  to  33 
microns.  The  median  layers  of 
lignin  between  the  cells  are 
broad,  and  are  colored  much 
darker  than  the  inner  layers 
of  the  cell-wall  when  treated 
with  iodine  and  sulfuric  acid. 
The  lumen  presents  the  same 
appearance  as  with  jute  (Fig. 
328),  having  such  very  marked 
contractions  that  in  places  it  is 
discontinuous.  The  ends  of  the 
fibers  are  very  blunt  and  thick- 
walled.  The  fiber  is  said  to  be 
white,  soft,  and  silky,  and  some 
claim  it  to  be  more  durable 
than  jute  for  the  manufacture 
of  coarse  textiles.  In  the  opinion 
of  the  author,  however,  these 
qualities  of  this  fiber  have  been 

somewhat  overestimated,  as  it 
Fig.  328.— Gambo   Hemp.     (X325.)      e,   Ends    .         ^  ,  .^         j       r^  i 

..,,,,      .  ,        J      A    1  J  1  i^     1   IS  not  as  white  and  soit  as  such 

with  blunt  pomts  and  wide  lumen;  a,  lateral 

branch;  I,  longitudinal  cutting  with  v,  inter-  descriptions  would  lead  us  to 
ruptions  in  lumen;  q,  cross-sections,  with  L,  expect.  According  to  Dodge, 
small  lumen;  m,  median  layers.     (Hohnel.)       the  fibers  of   ambari  hemp,  as 

compared  with  those  of  ordi- 
nary hemp,  are  of  a  paler  brown  color,  are  harsher,  and  adhere  more 
closely  together,  though  the  separate  fibers  are  further  divisible  into 
fine  fibrils  which  possess  considerable  strength.  According  to  Watt, 
the  fibers  of  ambari  hemp  are  largely  employed  by  the  natives  of 
India  for  the  manufacture  of  ropes,  strings,  and  sacks  which  are 
principally  used  among  the  agricultural  districts.  The  length  of  the 
extracted  fiber  varies  between  5  and  10  ft.;  the  fiber  is  somewhat  stiff 
and  brittle,  and  though  used  as  a  substitute  for  hemp  and  jute  is  inferior 
to  both.     The  breaking  strain  has  been  variously  estimated  at  115  to  190 


NEW   ZEALAND   FLAX 


803 


lbs.  The  fiber  is  bright  and  glossy,  but  coarse  and  harsh.  Samples  of 
the  fiber  exposed  for  two  hours  to  steam  at  2  atmospheres,  followed  by 
boiling  in  water  for  three  hours,  and  again  steamed  for  foiu-  hours,  lost 
only  3.63  percent  by  weight  as  against  flax  3.50;  Manila  hemp  6.07; 
hemp  6.18  to  8.44;  and  jute  21.39  percent. 

Another  variety  of  Hibiscus  which  is  sometimes  used  as  a  fiber  plant 
is  the  H.  esculentus,  or  common  okra.  The  bast  of  this  plant  at  one  time 
attracted  considerable  attention  in  the  Southern  States  as  a  possible 
substitute  for  jute  in  the  manufacture  of  bagging  for  cotton.  The  fiber 
is  said  to  be  as  white  as  New  Zealand  flax,  considerably  lighter  than  jute, 
but  more  brittle  and  not  so  strong.  The  filaments,  however,  are  smooth 
and  lustrous  and  quite  regular.  It  is  used  somewhat  in  India  for  the 
manufacture  of  twine  and  cordage,  and  as  an  adulterant  for  jute.  Accord- 
ing to  the  tests  of  Dr.  Roxburgh,  the  fiber  of  Indian  okra  gave  the  following 
results  compared  with  hemp  and  jute: 


Indian  okra 

Jute 

Hemp  (Bengal) .  .  .  . 
Hibiscus  cannabinus 

H.  sabdariffa 

H.  strictus 

H .  furcalus 


Breaking  Strain,  Lbs. 


Dry. 

Wet. 

79 

95 

113 

125 

158 

190 

115 

133 

95 

117 

104 

115 

89 

92 

The  bast  fiber  of  H.  tiliaceus  (the  majagua)  has  some  interest  in  the  fact 
that,  according  to  the  experiments  of  Dr.  Roxburgh,  it  does  not  rot  when 
immersed  in  water  for  a  long  period,  as  most  other  fibers  do.  His  results 
were  as  follows:  A  cord  of  this  fiber  when  white  had  a  breaking  strain  of 
41  lbs.;  when  tanned,  62  lbs.;  and  when  tarred,  61  lbs.;  a  similar  cord 
when  macerated  in  water  for  116  days,  when  white  broke  with  40  lbs.; 
when  tanned,  55  lbs.;  and  when  tarred,  70  lbs.  English  hemp  and 
Indian  hemp  when  treated  in  the  same  manner  were  found  to  be  rotten, 
and  sunn  hemp  broke  with  65  lbs.,  and  jute  with  60  lbs. 

23.  New  Zealand  Flax  or  Hemp  differs  somewhat  from  the  preceding 
fibers  in  that  it  is  derived  not  from  the  bast,  but  from  the  leaves  of  the 
flax  lily,  Phormium  tenax.  Botanically  these  are  known  as  sclerenchymous 
fibers.  Apart,  however,  from  this  histological  difference,  such  fibers  are 
very  similar  in  general  structure  to  ordinary  bast  fibers.  Phormium 
tenax  is  a  native  of  New  Zealand,  but  is  also  found  distributed  in  other 


804  JUTE,    RAMIE   AND   HEMP 

portions  of  Australasia  such  as  Norfolk  Island;  it  has  been  introduced 
into  several  European  countries,  and  is  also  cultivated  to  quite  an  extent 
in  Calfornia.i  The  fiber  of  New  Zealand  flax  is  very  white  in  color,  is  soft 
and  flexible,  and  possesses  a  high  luster.  In  tenacity  it  appears  to  be 
superior  to  either  flax  or  hemp,  as  is  seen  by  the  following  comparative 

figures  (Royle). 

Pounds 

New  Zealand  flax 23.70 

Flax 11.75 

Hemp 16 .  75 

Royle  also  furnishes  the  following  figures  for  the  breaking  strain  of 
similar  ropes  made  from  various  fibers: 

^.,  Breaking  Strain, 

^'^''-  Kilos. 

Coir 102 

Gambo  hemp 133 

Sansevieria  zeylanica 144 

Cotton 157 

Pita 164 

Sunn  hemp 185 

The  fiber  of  New  Zealand  flax  is  40  to  60  ins.  long,  nearly  white,  fine, 
and  rather  soft  for  a  leaf  fiber.  It  is  used  as  a  substitute  for  sisal  in  binder 
twine,  baling  rope,  and  medium  grades  of  cordage,  and  is  made  up  largely 
in  mixtures  with  Manila  or  sisal,  except  in  the  cheaper  tying  twines.  By 
extra  care  in  preparation  and  hackling,  a  quality  is  produced  almost  as 
fine  and  soft  as  the  better  grades  of  flax,  and  when  thus  prepared  it  may 
be  spun  and  woven  into  goods  closely  resembling  linen. 

The  leaves  of  Phormium  tenax  reach  over  5  ft.  in  length,^  and  the  fiber 

^  New  Zealand  flax  was  discovered  during  Captain  Cook's  first  voyage  in  1771. 
It  has  been  introduced  into  the  south  of  Ireland,  where  it  grows  luxuriantly;  it  is 
also  cultivated  as  an  ornamental  garden  plant  in  Europe.  It  has  also  been  intro- 
duced for  economic  puiposes  into  the  Azores  and  Cahfornia,  both  of  which  places 
yield  a  certain  quantity  of  the  fiber.  The  name  Phormium  is  derived  from  a  Greek 
word  meanmg  a  basket,  in  reference  to  the  use  made  of  its  leaves  by  the  New  Zealanders. 
Though  the  fiber  may  be  emploj^ed  either  alone  or  in  combination  with  flax  as  a  spinning 
and  weaving  material,  its  principal  use  is  as  a  cordage  fiber.  Though  of  high  tensile 
strength,  being  second  only  to  Manila  hemp  in  this  respect,  nevertheless  it  does  not 
withstand  alternate  wetting  and  drying  such  as  required  for  ship's  cordage.  It  is, 
however,  a  very  suitable  material  for  the  making  of  binder  twine  for  reaping  machines. 

2  The  leaves  are  sword-like  and  from  5  ft.  to  8  ft.  long  and  from  6  ins.  to  8  ms. 
wide,  the  fiber  being  distributed  throughout  the  leaf  as  a  support.  The  outer  surface 
of  the  leaf  is  of  a  bright  siliceous  character  and  very  hard.  The  other  portions  are 
also  hard  and  difficult  to  remove.  The  leaves  are  cut  with  a  sickle,  about  6  ins.  from 
the  crown  of  the  plant,  and  are  tied  in  bundles  averaging  about  90  lbs.  in  weight. 
If  cut  nearer  than  6  ins.  to  the  root,  gummy  matter  and  strong  red  dye  in  the  butt 
of  the  leaf  deleteriously  affect  the  fiber,  as  it  is  difficult  under  present  conditions  to 


NEW  ZEALAND   FLAX 


805 


is  separated  by  first  scraping  the  leaves  and  then  combing  out  the  separate 
fibers.  The  bundles  of  fibers  form  filaments  of  unequal  size,  which  are 
easily  separated  by  friction.  The  fiber  has  considerable  elasticity,  but 
readily  cuts  with 
the  nail  (Dodge). 
No  process  of  ret- 
ting is  necessary, 
as  with  the  bast 
fibers.  The  meth- 
od of  preparing  the 
fiber,  however,  is 
as  yet  very  unsat- 
isfactory, and  could 
be  much  improved. 
The  amount  of 
fiber  obtained 
under  the  present 
method  of  operat- 
ing is  from  10  to 
14  percent  on  the 
weight  of  the  leaves, 
although  the  latter 
contain  as  much 
as  20  percent  of 
fiber. 

In  their  microscopical  characteristics  the  fibers  of  New  Zealand  flax 
are  remarkable  for  their  slight  adherence.  The  fiber  elements  are  from 
5  to  15  mm.  in  length  and  from  10  to  20  microns  in  diameter,  and  the 

eliminate  the  gum  and  color.  When  the  trucks  of  phormium  leaves  reach  the  mill 
they  are  stacked  in  the  yard  to  be  sorted  and  prepared  for  stripping.  In  sorting,  the 
leaves  are  graded  into  several  quahties.  They  are  also  divided  up  into  different 
lengths  to  be  stripped  separately,  so  that  the  fiber  in  each  bundle  may  be  as  uniform 
as  possible  as  regards  both  quahty  and  length.  The  leaves  weigh  on  the  average 
about  17  ozs.  each.  In  the  work  of  stripping,  several  bundles  are  placed  on  a  table 
or  bench  to  the  right  of  the  operator,  who  feeds  the  machine  with  two  or  three  leaves 
at  a  time.  On  leaving  the  stripper,  the  fiber  is  washed,  and  when  fairly  dry  it  is  taken 
to  the  bleaching  and  drying  fields,  that  its  color  may  be  made  lighter  or  clearer  by 
exposure  to  the  weather. 

In  the  next  process  any  dry  surplus  vegetable  matter  which  may  still  remain 
attached  to  the  fiber  is  removed  by  the  scutcher,  which  knocks  off  loose  extraneous 
matter  and  the  rough  tail  ends.  The  short  fibers  and  the  dust  fall  behind  the  drum, 
and  after  being  well  shaken  to  remove  the  dust  and  rubbish,  constitute  what  is  known 
as  New  Zealand  tow,  which  is  also  exported  and  sells  at  a  very  fair  price,  as  it  con- 
tains many  of  the  finest  fibers.  One  of  the  things  which  is  wanted,  however,  is  a 
scutching  machine  which  will  make  less  tow  or  give  a  better  yield  of  long  fiber. 


Fig.  329.— New  Zealand  Flax.     (X300.) 
author.) 


(Micrograph  by 


806 


JUTE,   RAMIE   AND   HEMP 


ratio  of  the  length  to  the  breadth  is  about  550.  They  are  very  regular  and 
uniformly  thickened,  and  the  surface  is  smooth,  though  occasionally 
exhibiting  wavelike  irregularities  in  the  cell-wall  (Fig.  329).  The  lumen 
is  very  apparent,  but  is  generally  narrower  than  the  cell-wall  and  is  very 
uniform  in  its  width.     The  ends  are  sharply  pointed  and  not  divided. 

The    cross-section 
P    J  »f  shows  rather  loosel}' 

adhering  elements 
and  is  very  round 
in  contour,  the 
lumen  being  either 
round  or  oval,  and 
isempty  (Fig.  330). 
Fragments  of  pa- 
renchyma and  epi- 
dermis are  frequent- 
ly to  be  noticed 
on  the  fibers.  No 
median  layer  of 
lignin  is  apparent 
between  the  ele- 
ments, though  the 
fibers  themselves 
are  completely  lig- 
nified.  With  iodine 
and  sulfuric  acid 
the  fibers  give  an 
intense  yellow 
Fig.  330.— New  Zealand  Flax.  /,  Sclerenchymous  bundles;  coloration,  with 
p,  parenchymous  matter;  /',  vascular  fibers;  e,  fiber  ends;  aniline  sulfate  a 
p',  porous  elements  of  vascular  bundles;  q,  cross-section  of  p^le  vellow  with 
bast  fibers;  g',  cross-section  of  vascular  bundles;  J?,  cross-  ^hb^-iddide  of  zinc 
section   of  bast  fiber  bundle  with   accompanying  elements;  •  u   u 

ep,  epidermis;  c,  cuticle;   F,  bundle  proper;  7;,  parenchyma.    ^  yellowisn  brown, 
(Hanausek.)  with      ammoniacal 

solution  of  fuchs- 
ine  a  red;  with  Schweitzer's  reagent  the  fibers  are  rapidly  sepa- 
rated into  their  elements,  but  do  not  dissolve.  The  purified  fiber 
of  New  Zealand  flax  is  rather  difficult  to  distinguish  microscopically 
from  aloe  hemp  or  from  Sansevicria  fiber,  except  by  the  rounded  and 
separated  cross-sections.  The  fiber  also  usually  contains  a  substance 
derived  from  the  sap  of  the  leaf,  which  possesses  the  peculiarity  of  giving 
a  deep  red  color  with  concentrated  nitric  acid.  The  composition  of  the 
fiber  is  as  follows  (Church) : 


MARINE   FIBER  807 

Percent. 

Ash 0.63 

Water 11.61 

Gum  (and  other  matter  soluble  in  water) 21 .  99 

Fat 1.08 

Pectin  bodies 1 .  69 

Cellulose 63.00 

New  Zealand  flax  is  principally  employed  in  the  making  of  cordage 
and  twine  and  floor-matting,  though  the  best  fiber  can  also  be  woven 
into  cloth  resembling  linen  duck.  It  has  been  used  extensively  in  the 
United  States  for  the  making  of  "  staff,"  being  mixed  with  plaster  for  this 
purpose.^  The  chief  drawback  of  the  fiber  of  New  Zealand  flax  is  its 
poor  resistance  to  water. 

24.  Marine  Fiber. — This  is  a  recent  product  obtained  by  dredging 
in  the  shallow  water  of  a  gulf  in  South  Australia.  Chemically  it  is  a 
hydrated  lignocellulose,  giving  the  typical  reactions  of  lignin.  Micro- 
scopically it  is  verj^  similar  to  New  Zealand  flax.  From  this  it  is  to  be 
concluded  that  the  fiber  is  not  of  marine  origin,  but  has  been  produced 
by  the  natural  retting  of  a  land  plant,  which  has  become  submerged  by 
the  sea.  Owing  to  its  lignified  character  it  dyes  directly  with  basic  dyes 
and  some  acid  dyes,  but  has  little  affinity  for  substantive  dyes.  The 
fiber  is  brittle  and  has  but  little  strength. 

Marine  fiber  has  its  origin  in  the  leaves  and  stem  of  Posidonia  aus- 
tralis.  It  is  a  submerged  marine  flowering  plant,  and  the  enormous  beds 
of  the  fiber  which  have  been  discovered  appear  to  be  due  to  the  covering 
of  the  dead  bases  of  the  leaves  and  stems  by  the  shifting  sand  which 
serves  to  preserve  the  fiber  from  decay.  In  the  mass  it  is  pale  brown 
and  somewhat  lighter  in  color  than  cocoanut  fiber.  It  is  estimated  that 
the  workable  areas  of  South  Australia  alone  would  furnish  4,500,000  tons 
of  the  material.  Structurally  the  marine  fiber  filament  is  a  complex  of 
fiber  aggregates  resolvable  into  a  congeries  of  longitudinal  strands,  each 
of  which  may  be  distintegrated  further  into  ultimate  fibers  averaging  about 
one  millimeter  in  length.  The  filaments  themselves  are  composed  of  com- 
paratively coarse  and  short  staples,  tapering  with  occasional  swellings 
from  a  thick  to  a  fine  end.  They  are  rough,  have  a  low  degree  of  cohesion, 
have  but  little  luster  and  possess  a  harsh  feel.  The  tensile  strength  per 
unit  area  of  cross-section  is  somewhat  less  than  that  of  jute,  but  owing 
to  the  occurrence  of  many  flaws  its  practical  strength  is  much  less.  Its 
elasticity  under  steady  longitudinal  pull  is  very  high,  but  its  flexibility  is 
very  low.     In  its  chemical  nature  marine  fiber  appears  to  consist  of  a 

1  This  material  is  extensivelj^  employed  for  the  building  of  temporary  structures. 
It  was  used  on  most  of  the  structures  of  the  Columbian  Exposition  at  Chicago,  and 
at  the  Expositions  at  Buffalo,  St.  Louis  and  San  Francisco. 


808 


JUTE,   RAMIE   AND   HEMP 


lignocellulose  compound  intermediate  in  character  between  jute  and  wood 
fiber.  The  phloroglucinol  value  is  exceptionably  high,  and  the  color 
reactions  in  general  are  those  of  a  lignocellulose  more  reactive  than  jute. 
The  fiber  has  a  marked  resistance  to  dilute  alkalies,  zinc  chloride  solution, 
and  Schweitzer's  reagent.  It  is  readily  acted  on  by  halogens  and  has  an 
unusual  affinity  for  dyes.  The  fiber  yields  55  percent  of  cellulose  by  the 
chlorine-sulfite  process.  The  properties  of  the  fiber,  as  demonstrated  by 
the  studies  of  Read  and  Smith,  are  opposed  to  its  use  in  the  manufacture 
of  fine  textiles.  While  it  is  inferior  to  jute  in  flexbility  and  tensile  strength, 
it  is  greatly  superior  in  its  resistance  to  chemicals  and  bacterial  agents. 
It  is  being  employed  quite  extensively  as  an  insulating  material  for  heat. 
In  its  microscopic  appearance  marine  fiber  is  seen  to  consist  of  bundles 

of  ultimate  fibers  or 
fibrils,  firmly  cemented 
together,  and  present- 
ing the  appearance  of 
striated  bands.  Like 
hemp,  the  fibers  show 
at  intervals  pecuKar 
cross-markings  or 
cracks.  The  individ- 
ual fibrils,  separated 
by  steeping  in  chromic 
acid,  exhibit  a  broad 
regular  lumen  and 
finger-shaped  termina- 
tions. Chemically  the 
fiber  is  a  somewhat  hy- 
drated  lignocellulose 
giving  the  typical  reactions  of  lignin.  Thus,  with  aniline  hydrochloride  it 
gives  a  bright  yellow  color;  on  boiling  with  phloroglucinol  and  hydrochloric 
acid  it  gives  a  crimson  color;  with  ferric  ferrocyanide  it  is  colored  dark  blue; 
and  on  first  steeping  in  chlorine  water  and  then  transferring  to  a  solution 
of  sodium  sulfite  it  becomes  red.  With  strong  nitric  acid  it  becomes 
reddish  brown,  a  reaction  which  closely  resembles  that  of  New  Zealand 
flax.  The  fiber  as  it  comes  on  the  market  contains  a  considerable  quantity 
of  soluble  chlorides  (about  4  percent),  doubtless  derived  from  the  sea- 
water.  This,  combined  with  a  rather  large  ash  content,  makes  the 
material  rather  non-inflammable.  The  dyeing  properties  of  the  fiber  are 
rather  peculiar;  it  shows  the  greatest  affinity  for  the  basic  colors,  with 
which  it  is  readily  dyed  without  a  mordant,  thus  behaving  like  jute. 
With  acid  dyes  that  possess  also  residual  basic  qualities,  such  as  Patent 
Blue  and  Alkali  Blue,  it  also  dyes  fairly  well,  though  not  as  well  as  wool. 


Fig.  331. — Marine    Fiber.      A,  Single  fibers;    B,  bundles 
of  fibers;    C,  ends  of  fibers. 


MANILA  HEMP  809 

For  the  ordinary  acid  dyes,  however,  it  shows  no  affinity  at  all.  The 
fiber  also  shows  but  slight  attraction  for  the  substantive  cotton  or  direct 
dyes  and  the  sulfur  dyes,  differing  in  this  respect  from  cotton. 

Marine  fiber  has  been  used  in  Germany  under  the  name  of  posidonia. 
It  has  been  very  successfully  manufactured  into  yarns  and  fabrics  by  the 
Deutsche  Faserstoff-Gesellschaft.  After  being  brought  to  Germany  the 
fiber  is  subjected  by  this  concern  to  a  chemical  treatment  for  the  purpose 
of  softening  it  and  making  it  resilient,  the  original  fiber  being  stiff,  harsh, 
and  brittle.  The  staple  of  this  fiber  is  declared  to  be  equal  to  a  medium- 
staple  wool,  and  it  is  spun  on  the  worsted  and  woolen  system.  It  is  char- 
acterised by  elasticity  and  springiness,  and  the  cloth  which  is  made  out  of 
pure  posidonia  appears  to  show  scarcely  any  creases.  German  cloth  mills 
have  mixed  posidonia  with  wool  or  shoddy,  and  cloth  of  good  strength 
and  appearance  has  been  obtained.  It  is  believed  that  this  fiber,  by 
reason  of  its  springiness,  will  have  a  wide  field  of  use  in  the  carpet  industry. 
This  raw  material  was  sold  at  half  the  price  of  shoddy  before  the  War; 
since  the  War  none  of  this  has  been  imported  into  Germany. 

25.  Manila  Hemp. — This  is  the  fiber  obtained  from  the  leaf-stalks  of 
the  Musa  textilis,  a  variety  of  plantain  which  is  a  native  of  the  Philippine 
Islands.  The  commercial  supply  of  Manila  hemp  is  obtained  from  the 
Philippine  Islands;  "  cebu  hemp  "  is  a  trade  variety.  In  the  Philippines 
the  term  abaca  designates  both  the  plant  and  the  fiber  obtained  there- 
from. Properly  speaking  hemp  is  the  bast  fiber  obtained  from  the  inner 
bark  of  the  Cannabis  saliva,  whereas  Manila  hemp  is  entirely  different, 
being  the  structural  fiber  obtained  from  the  leaf-sheath  of  the  Musa 
textilis. 

The  plant  is  cut  down,  stripped  of  its  leaves  and  then  sliced  into  narrow 
longitudinal  strips  which  are  scraped  while  still  fresh  until  the  fibers  are 
exposed.  After  drying  the  fibers  are  beaten  and  are  separated  into  three 
grades:  (1)  Bandala,  the  coarsest  and  strongest  fibers  from  the  outer 
portion  of  the  trunk;  (2)  Lupis  from  the  middle  layers;  and  (3)  Tupoz, 
the  finest  and  weakest  fibers  from  the  inner  part  of  the  trunk.^ 

The  abaca  plants  attain  a  height  of  8  to  20  ft.,  the  trunk  being  com- 
posed chiefly  of  overlapping  leaf-sheaths.  When  the  flower-bud  appears, 
the  entire  plant  is  cut  off  close  to  the  ground.  The  leaf-sheaths,  5  to  12 
ft.  in  length,  are  stripped  off,  separated  tangentially  into  layers  a  quarter 
of  an  inch  or  less  in  thickness,  and  these  in  turn  split  into  strips  1  to  2  ins. 
in  width.  While  yet  fresh  and  green  these  strips  are  drawn  by  hand  under 
a  knife  held  by  a  spring  against  a  piece  of  wood.     This  scrapes  away 

^  Lupis  and  tupoz  serve  for  the  manufacture  of  fine  native  fabrics;  while  bandala 
is  used  for  a  coarse  fabric  known  as  Guimara,  and  more  especially  for  cordage  (see 
Semler,  Trop.  Agric,  vol.  3,  p.  712;  also  Schanz,  Die  Kultur  des  Manilahanfes  auf  den 
Philippinen;  Tropenpflanzen,  1904,  p.  116). 


810 


JUTE    RAMIE   AND   HEMP 


the  pulp,  leaving  the  fiber  clean  and  white.  After  drying  in  the  sun  tlie 
fiber  is  tied  in  bunches  and  taken  to  the  principal  towns  or  to  Manila  to 
be  baled  for  export. 

The  reproduction  of  the  abaca  plant  is  usually  by  suckers,  though  it 
may  also  be  carried  on  by  seed.  The  first  stalks  are  ready  for  harvesting 
twenty  months  to  three  years  after  planting,  depending  on  locality  and 
variety.  After  the  first  harvest  it  is  usual  to  cut  the  plantation  over  every 
six  or  eight  months.  The  mature  plant  consists  of  a  cluster  of  ten  to  thirty 
stalks  all  growing  from  one  root.  The  stalk  is  ready  for  harvest  when  the 
large  violet  flower  bracts  fall  to  the  ground.  Harvesting  is  done  by  hand 
with  a  sharp  knife.     The  yield  varies  greatly,  but  1000  lbs.  of  fiber  per 

acre    is    considered    a 
good  crop. 

A  single  plant  yields 
about  one  pound  of 
fiber.  The  fiber  is 
white  and  lustrous  in 
appearance,  light  and 
stiff  in  handle,  and 
easily  separated.  It  is 
also  a  very  strong  fiber, 
and  of  great  durability. 
In  the  Philippines  it 
is  known  as  abaca. 
According  to  Carter, 
to  extract  the  fiber 
from  the  leaves,  the 
native  first  makes  a  slight  incision  just  beneath  the  fiber  at  the  end, 
and,  giving  a  sharp  pull,  brings  away  a  strip  or  ribbon  of  the  outside 
skin  containing  the  fiber.  When  a  sufficient  number  of  ribbons  are  thus 
obtained  they  are  carried  to  the  knife  machine,  of  a  most  primitive  char- 
acter, consisting  of  a  rough  wooden  bench  with  a  long  knife  blade  hinged 
to  it  at  one  end  and  connected  at  the  other  to  a  treadle,  by  means  of 
which  the  operator  can  raise  the  knife  for  a  moment  in  order  to  insert  one 
end  of  a  fibrous  ribbon,  which,  being  twisted  round  a  small  piece  of  wood 
in  order  to  afford  a  good  hold,  is  dragged  through  between  blade  and 
block,  and  all  the  pulp,  weak  fiber,  and  pithy  matter  scraped  off.  The 
leaves  must  be  drawn  several  times  between  the  blade  and  the  bench 
before  the  fiber  is  sufficiently  clean.  The  unscraped  end,  which  is  held 
by  the  operator,  is  then  scraped  by  a  boy,  the  fiber  being  then  cleansed 
by  washing,  dried  in  the  sun,  and  packed  for  shipment.  One  man  can 
clean  about  50  lbs.  of  fiber  per  day. 

The  coarser  fibers  of  Manila  hemp  are  used  for  the  manufacture  of 


Fig. 


332.— Manila  Hemp.     ( 
dinal  views;    c,  ends. 


Cross-sections;    b,  longitu- 
(Cross  and  Bevan.) 


MANILA   HEMP 


811 


cordage,  for  which  purpose  it  is  eminently  suited  on  account  of  its  great 
strength.  The  Hght-colored  fibers  are  heckled  and  spun  into  j^arns  for 
coarse  weaving,  such  as  the  making  of  market-bags,  etc.  The  finer 
grades  are  also  used  sometimes  for  the  making  of  coarse  upholstery  goods. 
A  considerable  quantity  of  Manila  hemp  is  now  sent  to  Japan  where  it  is 
manufactured  into  Tagal  hat  braid  which  is  then  exported  chiefly  to  the 
United  States  where  it  is  used  for  women's  hats. 

The  best  grade  of  Manila  fiber  is  of  a  light  buff  color,  lustrous,  and  very 
strong,  in  fine,  even  strands  6  to  12  ft.  in  length.  Poorer  grades  are 
coarser  and  duller  in  color,  some  of  them  yellow  or  even  dark  brown,  and 
lacking  in  strength.     The  better  grades  are  regarded  as  the  only  satis- 


FiG.  333.— Manila  Hemp.     (Herzog.) 


factory  material  known  in  commerce  for  making  hawsers,  ship's  cables, 
and  other  marine  cordage  which  may  be  exposed  to  salt  water,  or  for  well- 
drilling  cables,  hoisting  ropes,  and  transmission  ropes  to  be  used  where 
great  strength  and  flexibility  are  required.  The  best  grade  of  binder 
twine  is  made  from  Manila  hemp,  since,  owing  to  its  greater  strength,  it 
can  be  made  up  at  650  ft.  to  the  pound  as  compared  with  500  ft.  for  sisal. 
The  grading  of  abaca  as  prescribed  by  Philippine  law  is  based  on  color, 
tensile  strength,  and  cleaning.  There  are  four  classes:  excellent,  good, 
fair,  and  coarse,  and  each  of  these  are  subdivided  into  a  total  of  twenty- 
one  grades  of  definite  description. 

The  relative  strengths  of  rope  made  from  English  hemp  and  that  made 
from  Manila  hemp  are  about  10  to  12  respectively.     The  finer  fibers  which 


812 


JUTE.    RAMIE   AND   HEMP 


require  to  be  selected  and  carefully  prepared,  are  woven  into  a  very  high 
grade  of  muslin,  which  brings  a  good  price  even  in  Manila.^ 

Under  the  microscope  Manila  hemp  shows  fiber  elements  of  3  to  12  mm. 
in  length  and  16  to  32  microns  in  width,  the  ratio  of  the  length  to  the  diam- 
eter being  about  250.  The  bundles  of  fibers  are  very  large,  but  by  treat- 
ment with  an  alkaline  bath  are  easily  separated  into  smooth,  even  fibers. 
The  fibers  are  very  uniform  in  diameter,  are  lustrous,  and  are  rather  thin- 
walled.  The  lumen  is  large  and  distinct,  but  otherwise  the  fiber  does  not 
exhibit  any  markings.  The  cross-sections  are  irregularly  round  or  oval  in 
shape,  and  the  lumen  in  the  section  is  open  and  quite  large  and  distinct 
(Fig.  332).  The  fiber  bundles  frequently  show  a  series  of  peculiar,  thick, 
strongly  silicified  plates,  known  as  stegmata.  Lengthwise  these  appear 
quadrilateral  and  solid,  and  have  serrated  edges  and  a  round,  bright  spot 


1  The  imports  of  Manila  hemp  into  the  United  States  during  1903  were  more  than 
500,000  bales  of  270  lbs.  each.  The  following  is  the  importation  of  Manila  hemp  into 
the  United  States  from  1909  to  1911: 


Year. 

Direct  from 

Philippines, 

Bales. 

Via  Europe, 
Bale.s. 

Total, 
Bales. 

1909 
1910 
1911 

775,643 
.594,724 
554,912 

10,563 

2,736 

986 

786,206 
597,460 
555,898 

Eight  bales  are  counted  as  a  ton. 

The  following  table  shows  the  exports  of  Manila  hemp  from  the  Philippines  since 
1899; 


Year. 

Weight, 

Value, 

Average 

Long  Tons. 

(Millions.) 

Price. 

1899 

70,152 

8 

$113.99 

1900 

90,869 

13 

146.81 

1901 

126,245 

16 

126 . 55 

1902 

113,284 

19 

170.29 

1903 

139,956 

22 

157.19 

1904 

123,583 

22 

169.48 

1905 

130,437 

22 

166.80 

1906 

104,078 

20 

188.44 

1907 

117,241 

20 

167.94 

1908 

131,382 

17 

125.61 

1909 

167,953 

17 

1 00 . 60 

1910 

163,173 

IG 

100.97 

1911 

148,202 

14 

97.74 

1912 

175,137 

22 

126  05 

1913 

119,821 

22 

176.27 

1914 

116,386 

19 

164.93 

1915 

142,010 

21 

1.50.27 

1916 

137,326 

27 

194.35 

1917 

169,435 

47 

276 . 26 

MANILA  HEMP 


813 


in  tho  center.  The  stegmata  may  be  best  observed  after  macerating  the 
fiber  bundles  in  chromic  acid  solution;  they  are  about  30  microns  in  length. 
On  extracting  the  fiber  with  nitric  acid,  then  igniting,  and  adding  dilute 
acid  to  the  ash  so  obtained,  the  stegmata  will  appear  in  the  form  of  a  string 
of  pearls,  frequently  in  long  chains  with  sausage  like  links,  a  very  peculiar 
and  characteristic  appearance  (Fig.  334).  The  lumen  often  contains  a 
yellowish    substance,    but 

no  distinct   median   layer       i  (~^Y(~~^  /-/tn^^  0 ) 

is  perceptible  between  the       ^tvy^^fp^v  ^^^^h^XWYrisi 

fibers.     Manila  hemp  is  a  V=^0\\    V\  ^\^X^:Sa 

lignified  fiber,  and  gives  a  v^r^CSYrxN  jtWYf\(\n 

yellow  color  with  aniline  ^~~— ^v::rr-^  J-'-'^^-^A^JX^ 

sulfate;  iodine  and  sul- 
furic acid  give  a  golden 
yellow  to   a   green   color;  __.^_,<c?-',-,'?r 

caustic     soda    colors    the        ^<^;ti-.fe'-;i.i>  a 

fiber  a  faint   j^ellow  and 
causes    a     slight     disten- 
sion;   ammoniacal  copper  "©151^13331?^^^®"^®^'^^^ 
oxide  causes  a  blue  color-  "    ^ 

ation   and  a  considerable  _ 

swelling.       Manila    hemp 

may  bo  distinguished  from  ^^'^-  ^'^'^- — Manila  Hemp,  q,  Cross-sections;  I,  lumen 
sisal  by  the    color    of    the        ^^''^^•'"'*    ''°"^:^'^^«'    /,    lumen    containing    granular 

matter;    a,   silicious    skeleton  oi   the  stegmata;    h, 
ash,    that    ot    the    former       ^.^^^^^  ^^  stegmata,  flat    side;    c,  the    same,  narrow 
being  of  a  dark  gray  color,      side.     (Hohnel.) 
whereas     sisal    leaves    a 

white  ash.  According  to  Miiller,  the  composition  of  Manila  hemp  is  as 
follows : 

Percent. 

Ash 1.02 

Water 11.85 

Aqueous  extract 0 .  97 

Fat  and  wax 0 .  63 

Cellulose 64.72 

In  crusting  and  pectin  matters 21 .  83 


Besides  the  Musa  textilis,  the  fiber  from  the  following  varieties  is  also 
utilised:  Musa  paradisiaca,  M.  aapientiuni,  and  M.  mindanensis  from 
India  and  islands  in  the  Pacific  Ocean ;  M.  cavendishi  from  China ;  M.  ensete 
from  Africa.  The  M.  sapientum  is  the  common  banana  plant  or  plantain. 
According  to  Dr.  Royle,  who  experimented  with  some  Indian  varieties  of 
the  sti'uctural  fiber,  its  strength  is  very  satisfactory.  His  results  are  as 
follows:    A  Madras  specimen  bore  a  weight  of  190  lbs.,  while  one  from 


814 


JUTE,    RAMIE   AND   HEMP 


Singapore  stood  360  lbs.,  and  Russian  hemp  bore  190  lbs.  A  12-tliread 
rope  of  plantain  fiber  broke  with  864  lbs.,  when  a  single  rope  of  pineapple 
broke  with  924  lbs.  Compared  with  English  and  Manila  hemjis,  a  rope 
3j  ins.  in  circmnference  and  2  fathoms  long  gave  the  following  results. 
The  plantain,  dry,  broke  at  2330  lbs.  after  immersion  in  water  twenty-four 
hours;  tested  seven  days  after  2387  lbs.,  and  after  ten  days'  immersion, 
2050  lbs.  Manila  and  English  hemp,  dry,  gave  4669  and  3885  lbs., 
respectively. 

In  the  extraction  of  the  good  fiber  from  the  abaca  there  is  a  great  deal 
of  waste  produced.  It  has  been  suggested  to  use  this  waste  for  the  manu- 
facture of  Manila 
paper  which  is  now 
made  principally 
from  old  Manila 
rope.  The  first  ex- 
periments in  this  line, 
however,  were  fail- 
ures as  the  waste 
had  only  a  relatively 
low  percentaf^e  of 
paper  fiber  and  its 
quality  was  too  vari- 
able; also  the  freight 
charges  were  prohi- 
bitive. Later  inves- 
tigations in  this  di- 
rection, however, 
promise  better  re- 
sults, for,  according 
Fig.  335.— Manila  Hemp.    (X300.)     (Micrograph  by  author.)    to  Commerce  Reports, 

in  1912  twelve  large 
paper  manufacturers  in  eastern  United  States  formed  a  Philippine 
corporation  to  handle  and  develop  the  use  of  abaca  and  its  by-products 
in  the  paper  industry.  The  enterprise  rests  upon  the  demand  for 
certain  classes  of  paper  of  an  especially  strong  and  tough  grade. 
Experts  report  that  a  1-in.  strip  of  hemp  paper  will  support  100  lbs. 
For  a  number  of  years  there  has  been  a  growing  demand  among  manu- 
facturers for  the  waste  products  of  hemp  and  old  rope  to  supply 
this  grade  of  paper,  especially  as  the  business  of  making  paper  bags 
for  cement,  flour,  and  similar  commodities  was  being  extended.  The 
organisation  backing  this  industry  has  spent  over  half  a  million  dollars 
in  experiments  but  reports  as  yet  no  substitute  for  hemp.  The  peculiarity 
of  Manila  hemp  is  that  it  is  practically  all  fiber  in  composition,  and  that  no 


MANILA  HEMP 


815 


matter  how  finely  the  hemp  is  divided  it  is  still  capable  of  division  as 
fiber,  while  a  fiber  of  cotton,  for  example,  is  only  a  tiny  tube,  a  fiber  of  sisal 
is  merely  non-fibrous  wood,  and  similar  objections  are  had  to  other  products. 
The  result  has  been  the  conclusion  that,  all  things  considered,  the  use  of 
the  whole  of  the  original  hemp  stalk  will  be  the  most  economical  way 
out  of  the  situation.  By  present  methods  about  one-third  of  the  ordinary 
plant  is  lost  in  stripping  and  about  one-third  of  the  remainder  is  not 
used  for  the  reason  that  the  fibers  are  too  small  and  too  weak  to  be  of 
commercial  use.  The  new  plan  is  to  take  the  entire  hemp  plant  as  cut  on 
the  plantation  and  merely  crush,  dry,  and  clean  it  in  especially  designed 
machinery.^ 

The  Bureau  of  Plant  Industry  of  Washington  gives  the  following 
results  of  numerous  tests  made  on  the  breaking  strength  of  Manila  hemp, 
together  with  some  other  hard  fibers.  These  tests  were  made  on  a  special 
machine  designed  for  testing  individual  fibers.  The  results  are  given  in 
the  following  table: 

Weight  and  Breaking  Strain  of  Hard  Fibers 


Fiber 


Abaca  (Manila  hemp),  Miisa  texlilis: 

Highest 

Lowest 

Average 

Heneqiien  (Yucatan  sisal),  Agave  fourcroya 

Sisal  (Hawaii  and  East  Africa),  Agave  sisalana.  .  . 

Cantala  (Manila  maguey),  Agave  cantala 

Phormium  (New  Zealand  hemp),  Phormium  tenax 

Zapupe  Vincent  (Agave  lespinassei) 

Cabuya  (from  Costa  Rica),  Furcraea  cabuya 


The 

Weight 

per  Yard, 

Grains. 


0.567 
0.962 
0.772 
0.765 
0.616 
0.429 
0.659 
0.722 
0.574 


Breaking 

Strain 

per  Strand, 

Grains. 


46.6 
31.0 
34.8 
16.7 
22.7 
9.6 
18.8 
21.5 
20.0 


Breaking 

Length 

in  Yards. 


82.2 
32.2 
45.0 
21.8 
38.4 
22.3 
28.5 
29.7 
32.2 


'  See  Glafey,  Die  Rohstoffe  der  Textilindustrie,  p.  72,  for  descriptions  of  the  portable 
machine  of  Duchemin  (Ger.  Pats.  197,658  and  199,082)  and  Boenkens  machine  (Ger. 
Pat.  171,237). 


CHAPTER  XXIV 
MINOR  VEGETABLE  FIBERS  AND  PAPER  FIBERS 

1.  Sisal  Hemp. — This  is  the  fiber  obtained  from  the  leaves  of  the  Agave 
rigida,  a  native  of  Central  America;  it  is  also  grown  in  the  islands  of  the 
West  Indies  and  in  Florida. 

The  fiber  of  the  Agave  was  probably  used  by  the  ancient  Mexicans  and 
Aztecs.  Cloth  woven  from  this  fiber  was  known  as  "  nequen,"  and  it  is 
interesting  to  know  that  the  Yucatan  name  for  the  commercial  sisal  hemp 
at  the  present  time  is  "  henequen." 

The  commercial  supply  of  sisal  hemp  is  produced  in  Yucatan,  only 
small  quantities  being  grown  in  Cuba  and  the  Bahamas.  According  to 
Semler  the  natives  cultivate  seven  varieties  of  the  plant  of  which  Chelem 
(A.  sisalana),  Yascheki  {Agave  sp.),  and  Sacci  are  the  most  important, 
while  Cajun  or  Cajum  {Fourcroija  cubensis)  and  F.  gigantea  yield  only 
coarse  fibers.  Giirke/  however,  has  shown  that  Agave  rigida  and  its 
variety  sisalana,  as  well  as  A.  elongaia,  yield  true  sisal  hemp,  while  Four- 
croya  gigantea  {F.  fcetida)  yields  Mauritius  hemp,  which  previously  was 
regarded  as  a  product  of  certain  species  of  Aloe. 

The  true  sisal  hemp  of  Florida  is  the  Agave  rigida,  but  there  is  also  a 
false  sisal  hemp  from  Florida,  which  is  frequently  confused  with  the  other. 
This  false  sisal  hemp  is  obtained  from  Agave  decipiens,  which  is  found 
wild  along  the  coast  and  Keys  of  the  Florida  peninsula.  There  is  consid- 
erable difference  in  the  habit  of  A.  decipiens  and  A.  rigida;  the  former 
throws  out  its  mass  of  leaves  from  the  top  of  a  foot-stalk  the  leaves  radiat- 
ing like  a  star,  and  the  color  being  in  strong  contrast  with  the  surrounding 
vegetation  (Fig.  336).  The  true  sisal  plant,  on  the  other  hand,  sends 
up  its  leaves  from  the  surface  of  the  ground.  The  leaf  of  the  A.  decipiens 
is  also  shorter  and  narror  er,  and  nearly  always  rolled  in  at  the  sides,  so 
that  the  cross-section  appears  like  the  letter  U ;  the  color  is  a  bright  green , 
the  leaf  also  possesses  very  strong  and  sharp  spines.  The  leaf  of  the 
A.  rigida  is  flatter  in  shape,  has  a  dark  green  color,  and  is  without  spines 
(Fig.  337).  With  respect  to  the  fiber  of  the  two  varieties,  that  of  the 
A.  decipiens  is  whiter,  finer,  softer,  and  greatly  deficient  in  strength. 
Tampico  hemp,  or  Mexican  fiber,  is  obtained  from  another  variety  of 

1  NoHzhl.  k.  Bol.  Gartens,  Berlin,  1896,  No.  4. 
816 


SISAL  HEMP 


817 


Agave  known  as  A.  heteracantha.  It  is  a  structural  fiber  like  the  others 
derived  from  the  leaves.  It  is  stiff,  harsh,  and  bristle-like  though  pliant, 
and  is  used  as  a  substitute  for  animal  bristles  in  the  manufacture  of  cheap 
brushes.  The  parenchyma  or  pith  of  the  leaf  squeezed  out  in  the  extrac- 
tion of  the  fiber  is  used  as  a  substitute  for  soap,  as  it  possesses  remarkable 
detergent  properties.     In  Mexico  the  fiber  is  commonly  known  as  "  istle." 

Sisal  has  a  light  yellowish  color,  and  is  very  straight  and  smooth; 
it  is  principally  used  for  making  cordage,  for  which  purpose  it  is  quite  valu- 
able, as  it  is  second  only  to  Manila  hemp  in  tensile  strength.  The  fiber 
is  easily  separated  from  the 
leaf,  and  does  not  require  a 
retting  process.  In  their  mi- 
croscopical appearance  the 
fiber  bundles  often  show  an 
interlaced  formation  with  a 
peculiar  spiral  vessel  and 
parenchyma  cells  containing 
single  calcium  oxalate  crys- 
tals, which  are  often  quite 
large  (Fig.  338). 

Sisal  hemp  is  cleaned  from 
the  leaves  by  machines  which 
scrape  out  the  pulp  and  at 
the  same  time  wash  the  fiber 
in  running  water.  It  is  then 
hung  in  the  sun  to  dry  and 
bleach  for  from  one  to  three 
days,  after  which  it  is  baled 
for  market.  More  than 
600,000  bales,  averaging 
about  360  lbs.  each,  were  im- 
ported by  the  United  States 
during    1903.     Sisal  fiber  of 

good  quality  is  of  a  slightly  yellowish  color,  2|  to  4  ft.  in  length,  somewhat 
harsher  and  less  flexible  then  Manila  hemp,  but  next  to  that  the  strongest 
and  most  extensively  used  hard  fiber.  It  is  used  in  the  manufacture  of 
binder  twine,  lariats,  and  general  cordage,  aside  from  marine  cordage  and 
derrick-ropes.  It  cannot  withstand  the  destructive  action  of  salt  water, 
and  its  lack  of  flexibility  prevents  it  fi'om  being  used  to  advantage  for 
running  over  pulleys  or  in  power  transmission.  It  is  extensively  used  in 
mixtures  with  Manila  hcmp.^  It  is  also  used  for  the  making  of  brushes 
and  as  a  substitute  for  horsehair. 

^  Yearbook,  Dept.  Agric,  1903. 


Fig.  336.— Florida  Sisal  Hemp.     (Dodge.) 


818 


MINOR   VEGETABLE   FIBERS  AND   PAPER   FIBERS 


Beadle  and  Stevens  ^  give  the  following  table  showing  the  relative 
strength  of  sisal  and  various  rope-making  fibers: 


Breaking 

Calculated 

Breaking 

Breaking 

Breaking 

Fiber. 

Strain  of 

Cross-section 

Strain, 

Strain, 

Length, 

Thread  in 

in 

Grams  per 

Tons  per 

Kilo- 

Grams. 

Sq.  Mm. 

Sq.  Mm. 

Sq.  In. 

meters. 

Sisal 

1375 

0.0240 

57,300 

36.2 

38.2 

Sansevieria 

1289 

0.0224 

57,540 

36.6 

38.4 

Manila 

1655 

0.0181 

91,430 

58.0 

60.9 

Hedychium 

828 

0.0093 

89,300 

56.7 

59.1 

Cotton  fiber 

8.2 

0.00026 

31,458 

20.0 

22.8 

Cellulose  monofil . 

294 

0.0140 

21,000 

13.3 

14.0 

Strong  paper 

10.0 

The  fiber  elements  of  sisal  hemp  are  from  1.5  to  4  mm.  in  length  and 
from  20  to  32  microns  in  breadth,  the  ratio  of  the  length  to  the  diameter 
being  about  1  :  100.  They  are  usually  quite  stiff  in  texture,  and  show  a 
remarkable  broadening  toward  the  middle.  The  width  of  the  lumen  is 
frequently  greater  than  that  of  the  cell-wall.  The  ends  are  broad,  blunt, 
and  thick,  but  seldom  forked.  The  cross-sections  are  colored  yellow  by 
iodine  and  sulfuric  acid,  and  show  no  evidence  of  a  median  layer  between 
the  elements.  The  sections  are  polygonal  in  outline,  but  often  have 
rounded  edges,  and  the  bundles  arc  usually  close  together.  The  lumen 
in  the  cross-section  is  large  and  polygonal  in  shape,  though  the  edges  of 
the  lumen  are  more  rounded  than  those  of  the  walls.  Short  thick-walled 
fibers  with  short-pointed  ends  are  present  in  large  numbers  in  sisal  hemp. 
They  show  a  narrow  lumen  and  distinct  surface  pores. 

The  ash  obtained  from  the  ignition  of  the  fiber  shows  the  presence  of 
glistening  crystals  of  calcium  carbonate,  which  are  derived  from  the 
original  crystals  of  calcium  oxalate  to  be  found  clinging  to  the  fiber  bundles. 
They  are  usually  in  longitudinal  series,  about  0.5  mm.  long,  and  taper 
off  at  the  ends  to  a  chisel  shape,  resembling  a  thick  needle  in  form,  but 
having  a  quadrilateral  cross-section.  The  occurrence  of  these  crystals  is 
very  characteristic  of  this  fiber.  On  the  coarse  fibers  employed  for  the 
manufacture  of  brushes  the  crystals  may  frequently  be  seen  with  the 
naked  eye. 

Other  fibers  often  confounded  with  true  sisal  are  those  derived  from  the 
Furcrcea  cuhensis  (cajun)  and  F.  gigantea  (giant  lily).  These  plants  are 
closely  allied  to  the  aloe  and  agave  and  grow  extensively  throughout 
tropical  America.  The  fiber  from  the  first  mentioned  is  largely  produced 
in  Trinidad  and  its  cultivation  there  has  met  with  considerable  success. 
1  Jour.  Soc.  Dyers  &  Col.,  1914,  p.  94. 


ALOE   FIBER  OR   MAURITIUS  HEMP 


819 


\i 


U 


The  green  leaves  yield  about  2  to  3  percent  of  good  fiber,  clean  and  of  fair 
color  and  equal  or  even  superior  to  sisal  in  quality.  The  Furcrcca  gigantca 
is  the  basis  of  a  considerable  fiber  industry  in  South  America  and  Mauri- 
tius. It  is  known  as  Aloes  vert  and  the 
green  leaves  yield  about  3  percent  of  the 
fiber,  which  is  known  under  the  name  of 
fique.  It  is  largely  used  for  the  making  of 
bags,  horse  blankets,  fish  nets,  and  similar 
coarse  fabrics.  A  considerable  quantity 
has  been  exported  to  the  United  States 
and  Germany. 

2,  Aloe  Fiber  or  Mauritius  Hemp. — 
This  is  obtained  from  the  leaf  of  various 
species  of  aloe  plants  growing  in  tropical 
climates.  The  principal  plant  employed  for 
Mauritius  fiber  is  Fourcroya  foetida.  In 
Porto  Rico  it  is  known  as  maguey,  but  is 
not  to  be  identified  with  the  Mexican  fiber 
of  the  same  name;  in  Hawaii  it  is  called 
malino,  which  is  probably  a  corruption  of 
manila.  The  only  locality  in  which  the 
fiber  is  produced  commercially  is  the  island 
of  Mauritius.  This  fiber  is  often  confounded 
with  that  of  the  Agave  americana,  but  it 
is  of  different  origin.  Aloe  fiber,  however, 
is  very  similar  to  Sansevieria  fiber,  and  is 
hardly  to  be  distinguished  from  it  in  either 
physical  or  microscopic  appearance.  The 
fiber  elements  are  from  1.3  to  3.7  mm.  in 
length  and  from  15  to  24  microns  in 
breadth.  Although  uniformly  broad,  the 
cell-wall  is  thin.  The  fibers  are  usually 
cylindrical  and  not  flattened;  they  show 
occasional  fissure-like  pores  (Fig.  340). 
The  cross-sections  are  polygonal,  with 
slightly  rounded  edges.  The  lumen  is 
usually  somewhat  broader  than  the  walls, 
and  in  the  cross-section  is  polygonal  with 
rounded  sides  (Fig.  341).  In  the  Sansevi- 
eria fiber  the  lumen  in  the  cross-section 
is  usually  larger,  and  the  cell-walls  con- 
sequently thinner;  furthermore  the  lumen  has  a  sharp-edged  polygonal 
form. 


I 


(■I 


,i," 


A  B 

Fig.  337.— True  and  False  Sisal. 
A,  Leaves  of  true  sisal  hemp 
plant;  B,  leaves  of  false  plant 
showing  thorny  edges.  (After 
Bulletin  U.  S.  Dept  Agric.) 


820 


MINOR  VEGETABLE   FIBERS   AND   PAPER  FIBERS 


Fia.  338.— Sisal  Hemp.     (X300.)     W,  Cell-wall;    P,  end  of  fiber;    S,  spiral-shaped 
sclerenchymous  tissue.     (Micrograph  by  author.) 


Fig.  339. — Decorticating  Machine  for  Sisal. 


PITA   FIBER 


821 


The  commercial  supply  of  aloe  fiber  is  obtained  from  Africa.  The 
fiber  is  whiter  and  softer  than  other  hard  fibers,  but  it  is  weaker  than 
sisal.  It  is  used  in  the  manufacture  of  gunny  bags,  halters,  and  hammocks, 
but  more  largely  for  mixing  with  Manila  and  sisal  in  making  medium 
grades  of  cordage.  When  the  better  grades  of  cordage  fiber  (Manila  and 
sisal)  are  abundant  and  quoted  low  in  the  market,  Mauritius  is  likely 
to  fall  below  the  cost  of  production.^ 

3.  Pita  Fiber  is  obtained  from  the  leaf  of  the  Agave  americana  or  cen- 
tury plant;  it  is  also  known  as  aloe  fiber.^  The  Agave  is  a  genus  of  fleshy- 
leaved  plants  belong- 
ing to  the  Amaryl- 
lidaceoe,  chiefly  found 
in  Mexico  and  Cen- 
tral and  South  Am- 
erica. They  are 
called  "  century  " 
plants  because  they 
are  supposed  to 
flower  but  once. 
From  some  of  the 
Mexican  species 
there  is  obtained  a 
distilled  liquor 
known  as  mescal, 
also  the  fermented 
beverage  called  pul- 
que. The  fiber  from 
A.  americana  (mag- 
uey plant)  is  a  struc- 
tural fiber  composed 
of     large     filaments 

readily  separated  by  friction.  According  to  Spon  the  agave  requires 
about  three  years  to  come  to  perfection,  but  it  is  exceedingly  hardy, 
easy  of  cultivation,  and  very  prolific,  and  grows  in  arid  wastes  where 
scarcely  any  other  plant  can  live.     It   perishes  after   inflorescence,   then 

1  Yearbook,  Dept.  Agric,  1903. 

2  The  term  "pita"  is  applied  to  several  fiber  plants  in  Central  and  South  America, 
including  sisal  hemp.  The  Columbian  Pita  is  a  plant  of  the  natural  order  Brov.eliacece, 
a  species  of  Aiianas.  In  habit  it  resembles  a  very  large  pineapple  plant  and  when 
mature  it  bears  20  to  40  leaves,  which  reach  a  height  of  10  ft.  The  natives  extract 
the  fiber  mechanically  by  scraping  away  the  non-fibrous  matter  with  a  stick.  The 
fiber  is  used  locally  for  making  fishing  nets  and  thread.  The  only  obstacle  at  present 
in  the  way  of  the  commercial  production  of  pita  fiber  is  the  lack  of  a  machine  for 
the  successful  extraction  of  the  fiber  from  the  leaves. 


Fig.  340. 


-Mauritius  Hemp.     (X300.) 
author.) 


(Micrograph  by 


822 


MINOR  VEGETABLE   FIBERS  AND   PAPER  FIBERS 


sends  up  numerous  shoots.  In  Mexico  5000  to  6000  plants  may  be 
found  on  an  acre;  the  average  number  of  leaves  is  40,  each  measuring 
8  to  10  ft.  in  length  and  1  ft.  in  width,  and  yielding  6  to  10  percent  by 
weight  of  fiber. 

The  pita  fiber  is  from  3  to  7  ft.  in  length.  According  to  Spon  its  main 
faults  are  the  stiffness,  shortness,  and  thinness  of  the  walls  of  the  individual 
fibers,  together  with  a  liability  to  rot.  Watt  states  that  it  takes  color 
readily  and  freely,  is  light,  and  contracts  under  water  rapidly.  Dodge 
states  that  a  distinctive  characteristic  of  the  pita  fiber  is  a  wavy  or  crinkled 
appearance  which  prevents  the  bundles  of  fibers  in  mass  from  lying  closely 

parallel,  as  in  the  case 
of  sisal  hemp  and  similar 
straight  fibers ;  another 
marked  peculiarity  is  its 
great  elasticity. 

There  are  several  va- 
rieties of  agave  fiber, 
which  are  known  by  their 
Mexican  or  Indian  names. 
The  best  known  of  these 
are  the  henequen  (Agave 
saxi),  the  ixtle  (Agave  am- 
ericana),  and  the  lechii- 
guilla  (Agave  heteracan- 
tha).  The  last  named  is 
also  known  as  Tampico 
or  Matamoros  hemp. 

The  fiber  of  Tampico 
hemp  is  stiff,  harsh,  but 
pliant  and  bristle-like; 
it  is  used  as  a  substitute  for  animal  bristles  and  for  the  making  of  cheap 
brushes.  The  fiber  as  obtained  from  the  leaf  is  from  18  ins.  to  2  ft.  in 
length.  The  pith  which  is  squeezed  out  in  extracting  the  fiber  possesses 
remarkable  detergent  qualities  and  is  a  valuable  substitute  for  soap. 
According  to  Dodge  the  native  name  of  the  lechuguilla  fiber  is  istle,  though 
this  name  appears  to  have  been  used  for  fiber  from  a  number  of  different 
species  of  plants;  it  is  stated,  however,  that  fully  90  percent  of  the  istle 
fiber  of  Mexico  is  from  the  Agave  heteracantha. 

Henequen  is  principally  grown  in  Yucatan,  and  was  extensively  used 
and  highly  prized  by  the  ancient  Mexicans,  and  still  is  at  the  present  time. 
The  fiber  is  white  to  pale  straw  in  color,  is  stiff  and  short,  has  a  rather 
thin  wall,  and  furthermore  is  liable  to  rot.  The  fibers  have  a  distinctive 
wavy  appearance,  and  another  peculiarity  is  its  great  elasticity.     According 


Fig.  341. — Mauritius  Hemp.     (Herzog.) 


PINEAPPLE  FIBER  OR  SILK  GRASS  823 

to  Royle,  Indian  pita  has  been  found  superior  in  strength  to  either  coir, 
jute,  or  sunn  hemp,  the  breaking  strain  on  similar  ropes  made  of  these 
materials  being  as  follows:  Pounds. 

Pita 2519 

Coir 2175 

Jute 2456 

Sunn  hemp 2269 


Fig.  342. — Century  Plant.     Agave  americana.     (Dodge.) 

Russian  hemp  and  pita,  on  comparison,  gave  a  relative  strength  of 
16  to  27.  Besides  its  use  as  a  cordage  fiber,  pita  is  also  employed  for 
the  making  of  a  very  delicate  and  beautiful  lace  known  as  Fayal.  In  its 
microscopical  characteristics  pita  is  very  similar  to  sisal  hemp. 

4.  Pineapple  Fiber  or  Silk  Grass.^ — This  is  obtained  from  A7ianas 
sativa  or  pineapple  plant.     This  fiber  has  great  durability  and  is  unaffected 

1  The  term  "silk  grass,"  though  apphed  to  this  fiber,  is  both  meaningless  and  a 
misnomer. 


824 


MINOR  VEGETABLE   FIBERS   AND   PAPER   FIBERS 


by  water.     It  is  very  fine  in  staple  and  highly  lustrous, 


Fig.  343. — Pita  Fiber.     (X300.)     Agave  americana.     (Micro- 
graph by  author.) 


These  are  from  3  to  9  mm 
ness.  The  lumen  is  very 
narrow  and  appears  like 
a  line.  The  cross-sec- 
tions are  polygonal  in 
outline  and  frequently 
flattened.  The  sections 
form  in  compact  groups 
which  are  often  crescent- 
shaped,  and  are  enclosed 
in  a  thick  median  layer 
of  lignified  tissue.  The 
fibers  are  accompanied 
by  vascular  bundles  in 
which  there  frequently 
occur  several  rows  of 
thick  and  strongly  ligni- 
fied fibers;  consequently 
there  are  two  classes  of 


in   length  and  from  4  to  8 


and  is  white,  soft, 
and  flexible.  It  is 
used  in  the  manu- 
facture of  the  cele- 
brated pina  cloth 
in  the  Philippine 
Islands.  Accord- 
ing to  Taylor,  a 
specimen  of  this 
fiber  was  subdi- 
vided to  one  ten- 
thousandth  of  an 
inch  in  thickness, 
and  was  considered 
to  be  the  most 
delicate  in  struc- 
ture of  any  known 
vegetable  fiber. 
Microscopically  it 
is  distinguished 
from  all  other  leaf 
fibers  by  the  ex- 
treme fineness  of 
its   fiber  elements. 

microns  in  thick- 


FiG.  344. — Pita  Fiber  from  Agave  americana.     (Herzog.) 


COIR   FIBER 


825 


fibers  to  be  distinguished:  (1)  long  and  extremely  fine  ones  which  are 
easily  curled,  with  very  narrow  and  fretiuently  scarcely  visible  lumen,  and 
with  long,  tapering,  blunt,  or,  sometimes,  almost  needle-shaped  ends, 
and  (2)  shorter  fibers  which  though  seldom  thick  are  often  stiff,  and 
which  occur  in  the  vascular  bundles  and  also  are  lignified  throughout. 

Arghan  is  the  name  given  to  a  pineapple  fiber  recently  brought  to  the 
attention  of  English  fiber  merchants,  and  considerable  has  been  written 
about  it  in  the  technical  press  as  a  "  new  "  textile  material.  It  has  been 
experimentally  made  into  twine  and  rope  and  found  to  be  eminently 


Fig.  345. — Pineapple  Plant.     (Dodge.) 


satisfactory,  being  of  great  tensile  strength  and  highly  resistant  to  sea- 
water;  it  is  claimed  to  be  fully  50  percent  stronger  than  hemp  or  flax. 
It  has  also  been  spun  into  fairly  fine  yarns  and  woven  into  cloth  with 
considerable  success.  It  has  been  suggested  as  a  substitute  for  hemp  and 
flax,  as  the  fiber  does  not  require  any  tedious  retting  process  in  its  prepara- 
tion, being  simply  obtained  from  the  pineapple  leaves  which  are  readily 
split  up  into  long  silky  fibers  of  a  pearly  white  color.  The  fiber  dyes  and 
bleaches  well  and  has  a  good  luster. 

5.  Coir  Fiber. — This  is  obtained  from  the  fibrous  shell  of  the  cocoanut 
(Fig.  346).     For  the  preparation  of  the  fiber,  the  unripe  nuts  are  steeped 


826 


MINOR   VEGETABLE   FIBERS  AND   PAPER  FIBERS 


Fig.  346. — Section  of  Cocoanut. 


in  sea-water  for  several  months,  after  which  the  fruit  is  beaten  and  washed 
away  with  water.  The  residual  reddish  brown  fibrous  mass  is  decorticated 
by  tearing  and  heckling  into  fibers  about  10  ins.  in  length.  The  fiber 
occurs  in  the  form  of  large,  stiff,  and  veiy  elastic  filaments,  each  individual 

of  which  is  round,  smooth,  and  some- 
what resembling  horsehair.  It  is  prin- 
cipally used  for  making  mats  and  cordage. 
It  possesses  remarkable  tenacity  and  curls 
easily.  In  color  it  is  cinnamon  brown. 
It  possesses  marked  microscopical  charac- 
teristics ;  the  fiber  elements  are  short  and 
stiff,  being  from  0.4  to  1  mm.  in  length 
and  from  12  to  24  microns  in  diameter, 
the  ratio  of  the  length  to  the  thickness  is 
only  35.  The  cell-wall  is  thick,  but  rather 
irregularly  so,  in  consequence  of  which  the 
lumen  has  an  irregularly  indented  outline 
(Fig.  347).  The  points  terminate  abruptly 
and  are  not  sharp,  and  there  appear  to 
Husk  containing  fiber;  b,  the  fniit  be  a  large  number  of  pore-canals  pene- 
or  edible  portion.  (After  Bulletin  trating  the  cell- wall  (Fig.  348).  On  the 
U.  S.  Dept.  Agric.)  surface  the  fiber  bundles  are  occasionally 

covered  with  small  lens-shaped,  silicified 
stegmata,  about  15  microns  in  breadth.  These  stegmata  fuse  together 
on  ignition,  giving  a  blister  on  the  ash.  If  the  fiber  is  boiled  with  nitric 
acid  previous  to  its  ignition,  the  stegmata  then  appear  in  the  ash 
like  yeast-cells  hanging  together  in  the  form  of  round,  silicious 
skeletons. 

Coir  gives  the  following  microchemical  reactions:  with  iodine  and 
sulfuric  acid,  golden  yellow;  with  aniline  sulfate,  intense  yellow;  Schweit- 
zer's reagent  does  not  attack  the 
fiber.  These  reactions  indicate  a 
lignified  fiber.  According  to  Schles- 
inger,  coir  contains  20.6  percent  of 
hygroscopic  moisture. 

The  cross-section  of  the  fiber  is 
oval  in  shape  and  yellowish  brown 
in  color,  and  enclosed  in  a  network 
of  median  layers.      Coir  fiber  is 

employed  in  the  South  Seas  instead  of  oakum  for  caulking  vessels,  and  it 
is  claimed  that  it  will  never  rot.  The  principal  use  for  coir,  however,  is 
for  cordage  and  matting.  For  cable-making  it  is  said  to  be  superior  to  all 
other  fibers,  on  account   of  its  resistance   to  water,  lightness,  and  great 


Fig.  347.— Coir  Fiber.  (X300.)  s,  Serra- 
tions in  wall  of  lumen;  p,  pores  in  wall; 
Si,  silicious  skeleton  from  stegmata.  (Mi- 
crograph by  author.) 


COIR  FIBER 


S27 


elasticity.     It  also  has  a  great  resistance  to  mechanical  wear.     Wright 

gives  the  following  tests  on  various  cordage  fibers: 

Pounds. 

Hemp 190 

Coir 224 

Bowstring  hemp 316 

Ceylon  is  the  home  and  center  of  the  preparation  of  coir  fiber  and 
yarn,  from  which  cordage  and  coarse  clorhs  are  made,  and  the  bristles 
are  made  into  brushes.  Galle,  on  the  southwest  of  the  island,  is  the  chief 
seat  of  the  native  manufacture  and  its  fiber  is  considered  superior  to  the 
mill  product.  The 
cocoanut    husks     are  ^       ^^ 

thrown  into  a  bamboo  -^         ^'*'' 

enclosure,  which  the 
natives  have  built  in 
the  sea,  and  after  soft- 
ening for  six  days  in 

the  water,  the  wood    /  5  ///( 

is  pounded  apart  from 
the  fibers  with  a  stone, 

after  which  the  fiber  is    '  ^^~^=S^:S^^    "^ 

heckled  with  a  wooden 
comb  and  dried. 

When  the  fiber  is 
prepared  by  machin- 
ery the  process  is 
different ;  but  the 
hand-prepared  prod- 
uct is  regarded  as 
much  superior.  The  Fig.  348. — Coir  Fiber.  (X300.)  (Micrograph  by  author.) 
husks    are    purchased 

by  the  bullock  cart  load  at  about  8  cents  per  hundred,  or  even  for 
the  cart  hire.  They  are  quartered  and  put  in  large  water  tanks  and 
weighted  with  a  network  of  iron  rails.  After  five  days  the  husks  are 
removed  and  run  through  a  machine  composed  of  two  corrugated  iron 
rollers  known  as  a  breaker,  which  will  crush  them  and  prepare  them  for  the 
next  machine,  called  the  "  drum." 

The  drums  are  in  pairs,  a  coarse  one  for  the  first  treatment  and  a  finer 
one  for  the  second.  They  are  circular  iron  wheels  3  ft.  in  diameter, 
which  revolve  at  high  speed  and  have  rims  about  14  ins.  wide  studded  with 
spikes.  The  husks  are  held  against  the  revolving  drums  and  the  spikes 
tear  out  the  woody  part,  leaving  the  long,  coarse  fibers  separate.  The 
torn  and  broken  fiber  that  falls  from  the  drum  spikes  is  fanned,  then 


828  MINOR  VEGETABLE  FIBERS  AND  PAPER  FIBERS 

dried  by  being  spread  out  in  the  sun,  and  subsequently  cleaned  and  baled 
as  mattress  fiber.  The  longer  and  stronger  fibers  are  washed,  cleaned, 
and  dried,  and  then  taken  to  a  room  where  they  are  further  heckled  by 
women,  who  comb  them  through  long  rows  of  steel  spikes  affixed  to  tables. 

The  fibers  are  now  in  hanks  about  a  foot  long  and  as  thick  as  a  man's 
forearm.  They  are  bound  together,  put  into  a  hydraulic  press,  and  baled 
for  shipment  as  bristle  fiber  for  making  brushes,  etc. 

From  the  finer  qualities  of  fiber  used  for  mattresses  there  is  spun  what 
is  known  as  coir  j^arn,  in  threads  one-fourth  of  an  inch  thick  and  perhaps 
50  ft.  long.  It  is  from  these  that  a  very  superior  rope  and  several  kinds 
of  coarse  cloth  are  made.  Coir  yarn  is  manufactured  chiefly  at  Galle, 
and  is  mostly  shipped  from  that  port  with  transshipment  at  London. 
On  the  local  market  there  are  two  principal  grades,  the  first  grade  known 
as  Kogalla  yarn,  and  the  second  as  Colombo  yarn.  These  two  grades  are 
subdivided  into  15  to  24  slightly  different  standards,  according  to  thickness, 
color,  and  twist.  It  is  estimated  that  1000  cocoanut  husks  will  produce 
70  to  80  lbs.  of  bristle  fiber  and  about  300  ll3s.  of  mattress  fiber  and  yarn. 

Besides  the  fiber  from  the  husk  of  the  cocoanut  the  leaf  of  the  cocoanut 
palm  also  yields  a  fiber  that  has  considerable  use.  The  fresh  leaves  of  the 
cocoanut  palm  are  first  boiled  in  water  for  a  short  time,  and  then  torn 
apart  into  upper  and  lower  halves.  Then  each  half  is  torn  by  hand  or 
suitable  devices  into  strips  of  a  suitable  width.  These  strips  are  then 
boiled  from  one  to  two  hours  in  a  solution  consisting  of  5  to  8  lbs.  of  sodium 
carbonate,  dissolved  in  100  lbs.  of  water.  After  the  above  treatment,  the 
material  is  washed  once  in  clean  water  to  eliminate  various  impurities. 
Then  it  is  put  in  a  bleaching  solution  made  of  100  lbs.  of  water,  1  to  3  lbs. 
of  sodium  peroxide,  1  to  2  lbs.  of  potassium  oxalate,  and  50  to  100  grams 
of  sulfuric  acid,  for  a  period  extending  over  one  to  three  days.  During 
the  infusion  the  material  is  stirred  and  disturbed  from  time  to  time.  After 
the  completion  of  the  bleaching  process  the  material  is  well  washed  by 
water  and  dried  in  the  shade  with  a  free  exposure  to  air. 

The  strip  of  leaf  thus  treated  rolls  in  from  both  edges  when  dried,  and 
becomes  a  smooth,  semi-transparent  thread  which  is  strong,  elastic,  light, 
and  good-feeling,  and,  moreover,  is  quite  waterproof.  A  hat  or  bonnet 
made  of  such  thread  does  not  become  deformed  or  decolorised  even  after 
a  long  period  of  exposure  and  wear;  and  it  is  claimed  that  such  hats  are 
equal  in  quality  to  the  true  Panama  hat.  The  threads  may  also  be  usefully 
employed  in  the  manufacture  of  cloths,  mats,  bags,  slippers,  etc. 

6.  Istle  Fiber. — This  is  otherwise  known  as  Tampico  fiber,  and  is 
obtained  from  the  leaves  of  several  species  of  Mexican  plants  which  are 
principally  found  in  the  desert  table-lands  of  northern  Mexico  (Fig.  349). 
The  most  important  istle  fibers  are  Jaumave  lechuguilla,  Jaumave  istle, 
lechuguilla,  Tula  istle,  Palma  samandoca,  and  Pahna  pita.     The  principal 


ISTLE   FIBER 


829 


plants  yielding  the  fiber  are  Agave  heteracaniha,  A.  lechuguilla,  and  Samuella 
carnerosana. 


Fig.  349.— Tampico  Hemp  Plant.     (Dodge.) 

Palma  istle  fiber  is  15  to  35  ins.  in  length,  usually  coarser  and  stiffer 
than  sisal,  j^ellow  in  color,  and  somewhat  gummy.  Tula  istle  is  12  to  30 
ins.  long  and  nearly'  white  in  color.  Jaumave  istle  is  20  to  40  ins.  long, 
rarely  longer,  almost  white,  and  nearly  as  strong  and  flexible  as  sisal. 


Fig.  350.— a  Leaf  of  Agave  heteracantha.     (After  Bulletin  U.  S.  Dept.  Agric.) 


The  importations  of  istle  fiber  into  the  United  States  had  increased  from 
less  than  4000  tons  in  1900  to  more  than  12,000  tons  in  1903.  Istle  fiber 
has  long  been  used  as  a  substitute  for  bristles  in  the  manufacture  of  brushes, 
and  it  is  now  being  employed  in  increasing  quantities  in  the  cheaper 


830  MINOR  VEGETABLE    FIBERS  AND   PAPER  FIBERS 

grades  of  twine,  such  as  lath  twine,  baling  rope,  and  medium  grades  of 
cordage.  Introduced  at  first  as  an  adulterant  or  substitute  for  better 
fibers,  it  seems  destined  to  find,  through  improved  processes  of  manufacture, 
a  legitimate  place  in  the  cordage  industry.  If  machines  are  devised  for 
cleaning  this  fiber  in  a  satisfactory  manner,  it  is  thought  that  the  thousands 
of  acres  of  lechuguilla  plants  in  western  Texas  may  be  profitably  utilised. 

Istle  fiber  is  used  largely  for  making  brushes;  it  is  also  made  into 
cordage  and  woven  into  coarse  sacks  for  containing  grain.  The  com- 
mercial fiber  is  from  12  to  30  ins.  in  length,  and  is  coarse  and  harsh. ^ 
The  color  of  the  fiber  is  deep  yellow,  but  on  boiling  with  water  this  coloring 
matter  is  almost  altogether  removed.  The  parenchymous  tissue  separated 
from  the  fiber  is  used  as  a  substitute  for  soap,  and  even  the  commercial 
fiber  gives  a  soapy  solution  when  boiled  with  water. 

7.  Nettle  Fiber.- — This  fiber  is  used  to  some  extent  for  spinning, 
being  cultivated  for  this  purpose  in  certain  parts  of  Germany  and  in  the 
province  of  Picardy  in  France.  The  product  known  by  the  specific  name 
of  nettle  fiber  is  obtained  from  two  species  of  the  stinging  nettle,^  Urtica 
dioica  and  Urtica  urena.  The  Bcehmeria  (see  Ramie  and  China  grass) 
are  also  nettle  plants,  but  belong  to  the  stingless  variety.  The  Urtica 
dioica  yields  the  largest  amount  of  fiber,  but  of  large  diameter  and  very 
thin  cell-wall;  the  fibers  from  the  second  species,  Urtica  urena,  are  much 
smaller  in  diameter  and  have  a  thick  cell-wall,  resembling  linen  fibers  to  a 
great  extent;   its  chief  drawback  is  the  small  yield  of  fiber  from  the  plant. 

The  nettle  fiber  appears  to  consist  of  pure  cellulose,  with  occasional 
traces  of  lignin  on  the  surface.  It  gives  the  following  microchemical 
reactions:   (a)  with  iodine-sulfuric  acid  reagent,  blue  coloration;^   (b)  with 

1  Imitation  horsehair,  according  to  a  recent  French  patent,  may  be  prepared  from 
Tampico  fiber  by  digesting  100  parts  of  the  material  for  six  hours  under  the  pressure 
of  three  atmospheres  with  a  sokition  consisting  of  23  parts  by  vokime  of  caustic  soda 
solution  of  36  Be.  and  1500  parts  by  volume  of  water.  After  rinsing  the  fibers  are 
steeped  for  fifteen  minutes  in  a  bath  containing  one  part  of  sulfuric  acid  per  100  parts 
of  water.  They  are  then  washed,  dried  and  put  through  a  carding  machine.  For  a 
bleached  product  the  material  is  steeped  for  about  eight  hours  in  a  solution  of  800 
grams  of  bleaching  powder  per  100  liters  of  water  before  the  treatment  with  acid.  Curly 
fibers  are  obtained  by  steeping  the  degummed  fibers  in  a  solution  of  caustic  soda  at 
18°  Be.  for  about  an  hour. 

^  See  Wiesner,  Rohstoffe  des  Pflanzenreiches,  vol.  2,  p.  214;  Moller,  Die  Nesselfoser, 
Pulytechnische  Zeiinng,  1883;  Hohnel,  Mikroskopie  der  Faserstoffe,  p.  52;  Dodge, 
Useful  Fiber  Plants,  p.  323. 

^  The  stinging  nettle  is  also  common  in  the  United  States;  it  grows  principally  on 
waste  lands.  It  has  not  been  used  as  a  fiber  plant  in  this  country,  however.  In 
Sweden  it  is  cultivated  to  some  extent  for  its  fiber,  being  known  as  Swedish  hemp; 
it  is  used  for  cordage,  cloth,  and  fisli-hnes.  In  India  it  is  known  as  Bichu  or  Chicru, 
meaning  scorpion  or  stinger. 

''  The  lumen  of  the  fiber,  especially  toward  the  ends,  is  often  filled  with  matter 
which  gives  a  yellow  color  with  this  reagent. 


NETTLE   FIBER 


831 


ammoniacal  fuchsine  solution,  no  coloration;  (c)  with  sulfate  of  aniline, 
no  coloration;  (d)  with  chlor-iodide  of  zinc,  bluish  violet  coloration; 
(e)  with  chlor-iodide  of  calcium,  rose-red  coloration. 

The  fibers  of  Urtica  dioica  vary  in  length  from  5  to  55  mm.  (Vetillart) 
and  in  diameter  from  0.020  to  0.080  mm.  Under  the  microscope  the  fibers 
are  characterised  externally  by  fine  oblique  striations;  the  ends  of  the 
fibers  are  finely  pointed.  According  to  Hohnel,  in  its  microscopic  charac- 
teristics the  nettle  fiber  is  very  irregular  and  unevenly  marked,  creased, 
and  in  part  ribbon-like  in  form.  The  lumen  is  wide,  and  often  contains  a 
yellow  substance.  The  ends  are  tapered,  rounded  off,  and  many  times 
split  or  forked.  The  cross-section  is  oval,  flattened,  or  even  has  the  walls 
turned  in.  The  latter  are  thin  and  are  stratified  in  a  pronounced  degree, 
the  inner  layers  frequently  being 
marked  radially. 

The  cross-sections  of  the  fibers 
are  oval  and  show  thin  cell-walls, 
which,  however,  at  times  may  become 
quite  thick,  owing  to  irregularities  in 
the  structure  of  the  fiber.  The  fiber 
is  supple,  long,  and  soft  to  the  touch; 
like  ramie  it  possesses  great  resistance 
to  water;  it  is,  however,  comparatively 
weak  in  strength,  owing  to  the  thin 
cell- wall  and  irregular  structure. 

On  account  of  the  thin  cell-wall, 
the  nettle  fiber  gives  only  faint  colora- 
tions   when    viewed    under    polarised 

light.  In  Germany  the  nettle  fiber  is  spun  into  a  greenish  colored  yarn 
known  as  Nesselgarn,  this  is  woven  into  a  cloth  called  Nesseltuch,  which 
may  be  bleached  to  a  pure  white,  and  much  resembles  linen  cloth. 

During  the  War  much  was  said  and  written  in  Germany  about  the 
cultivation  and  use  of  the  nettle  fiber  for  textile  manufacture,  but  it  may 
be  assumed  that  the  experiments  made  were  not  very  successful,  as  but 
little  is  heard  to-day  of  the  use  of  the  nettle  fiber.  The  difficulties  of 
cultivating  the  nettle  would  probably  be  as  great  as  those  of  cultivating 
flax,  and  it  would  seem  better  to  improve  and  develop  the  latter  plant,  the 
characteristics  of  which  are  so  well  known,  rather  than  to  attempt  the 
development  of  a  new  plant  industry. 

The  best  specimens  of  textile  nettles  are  found  in  the  tropics  and 
include  the  Urtica  capitata,  growing  to  the  height  of  3  to  5  ft.,  and  the 
Urtica  chamcedry aides,  which  is  from  6  to  30  ins.  in  height  and  plentiful 
in  the  United  States. 

The  use  of  the  nettle  as  a  textile  fiber  dates  from  very  early  times. 


Fig.  351.— Nettle  Fiber. 


832  MINOR  VEGETABLE  FIBERS  AND  PAPER  FIBERS 

The  Egyptians  and  the  ancient  Scandinavians  used  it.  The  account  of  the 
third  voyage  to  the  coast  of  Kamchatka  states  that  the  natives  used  the 
nettle  fiber  to  make  rope,  twine,  and  sewing  thread.  The  ancient  records 
note  the  use  of  the  nettle  in  Germany  and  Russia.  It  was  also  known  in 
Italy  and  France  during  the  Middle  Ages.  The  Encyclopedia  of  the 
eighteenth  century  contains  an  article  on  the  production  and  use  of  the 
nettle,  which  states  that  it  is  manufactured  into  yarn  in  Germany.  About 
the  same  period  experiments  with  the  nettle  were  carried  on  in  Angers 
and  Mons  with  very  satisfactory  results.  At  the  beginning  of  the  nine- 
teenth century  there  was  a  permanent  trade  in  nettle  goods  carried  on  in 
Picardy,  Germany,  and  Sweden. 

During  the  past  century  there  have  been  numerous  attempts  to  cultivate 
and  use  the  nettle,  including  Bartoloni  in  Tuscany,  1809;  by  Edward 
Smith  in  England,  1810;  and  by  Withlow  in  the  United  States,  1814. 
Among  those  who  engaged  in  this  work  it  is  necessary  to  include  a  number 
of  Frenchmen,  the  Abbe  Rozier,  1793;  Chalumeau,  1803;  Chaumeton, 
1818;  Lardier,  1820;  Chatin,  1861;  Eloffe,  1869;  Barot,  1891; 
d'Astanieres,  1894;  Michotte,  1895.  The  Abbe  Provenchir,  1862,  reported 
that  the  nettle  was  used  in  Canada  in  the  manufacture  of  cloth  and  cordage. 
At  the  Paris  Exposition  in  1878  Japan  exhibited  a  large  collection  of  nettle 
fibers,  yarn,  and  fabrics.  Experiments  in  nettle  culture  have  been  made 
for  some  years  on  plantations  in  Russia. 

The  appearance  of  the  nettle  fiber  varies  with  the  method  of  extraction. 
After  decorticating  the  bark  in  the  green  state,  the  fibers  are  in  the  form  of 
a  greenish  ribbon,  harsh  to  the  touch,  about  60  ins.  long  and  containing 
more  or  less  woody  matter  according  to  the  thoroughness  of  the  decorti- 
cation. These  filaments  rapidly  assume  a  reddish  gray  shade  and  in  that 
condition  it  is  difficult  to  distinguish  them  from  ramie  or  green  hemp. 
The  combed  fibers  are  in  the  form  of  regular  filaments  from  1  to  1|  yds 
in  length  and  free  from  woody  matter.  The  green  shade  is  more  uniform 
and  the  fiber  is  flexible  and  soft  to  the  touch,  especially  if  the  combs  have 
been  oiled.  The  material  when  degummed  in  the  raw  state  is  a  yellowish 
white.  When  degummed  and  bleached,  but  not  combed,  it  has  the 
appearance  of  flax.  The  combed  stock  has  an  appearance  similar  to  that 
of  degummed  ramie. 

The  retted  fiber  varies  widely  according  to  the  method  of  retting  that 
has  been  used.  Retting  in  running  water  produces  ribbons  of  soft  fibers, 
lustrous,  and  the  color  of  straw.  When  retted  in  standing  water  the 
color  is  a  dirty  gray,  as  is  the  case  when  the  stock  is  retted  in  the  fields. 
Certain  precautions  are  necessary  in  working  fresh  nettle.  The  stinging 
nettle,  growing  14  to  20  ins.  high,  is  more  irritant  than  the  dioecious 
nettle,  which  grows  to  the  height  of  40  to  70  ins. 

According  to  Dr.  Grothe,  100  lbs.  of  green  bark  yield  46  lbs.  after  drying, 


SANSEVIERIA  FIBERS  833 

producing  32  lbs.  of  filasse,  which  in  turn  yields  20  lbs.  of  combed  filasse. 
The  extraction  of  the  fiber  by  decortication  is  preferable  to  retting  and  the 
apparatus  used  for  working  ramie  serves  perfectly  for  the  nettle  fiber. 
The  decortication  should  immediately  follow  cutting.  It  is  difficult  to 
decorticate  the  material  if  the  fibers  have  been  cut  more  than  eight  hours 
previously;  at  the  end  of  twenty-four  hours  decortication  becomes  impos- 
sible. The  strips  of  fiber  obtained  by  decortication  are  dried  or  retted 
according  to  the  process  selected.  The  material  is  generally  dried  in  the 
open  air  and  the  fibers  are  separated  by  degumming  by  chemical  means 
or  by  retting. 

The  chemical  process  is  similar  to  that  used  for  ramie,  the  material 
being  immersed  in  a  solution  of  soap  and  hypochlorite  of  ammonia.  The 
retting  process  is  similar  to  that  employed  for  flax,  hemp,  and  similar 
materials.  The  nettle  fiber  is  soft  and  flexible,  the  length  varying  from 
I  to  2  ins.     It  is  in  many  respects  like  the  ramie  fiber. 

8.  Fiber  of  Urena  Sinuata. — The  plant  from  which  this  fiber  is  obtained 
is  a  small  shrub  growing  generally  in  the  tropics.  In  America  it  is  known 
as  Caesar  weed;  in  Venezuela  it  goes  by  the  name  of  Cadilla.  The  bast 
fiber  resembles  jute  in  appearance,  being  yellowish  in  color,  of  considerable 
brilliancy,  and  also,  like  jute,  deteriorating  in  moist  air.  The  average 
length  of  fiber  bundles  is  6  ft.  The  fiber-cells,  according  to  Wiesner,  have 
a  length  of  about  1.8  mm.,  and  an  average  diameter  of  15  microns.  The 
lumen  of  the  fiber  is  very  irregular  in  width,  but  is  mostly  rather  broad, 
though  not  so  large  as  that  of  jute.  With  iodine  and  sulfuric  acid  the 
fiber  gives  a  yellow  color;  aniline  sulfate  also  gives  a  deep  yellow,  which 
indicates  strong  lignification ;  Schweitzer's  reagent  produces  a  strong  swell- 
ing of  the  cell-wall.  There  may  often  be  observed  on  Urena  fibers, 
under  the  microscope,  cells  of  parenchymous  tissue  containing  crystalline 
deposits.  The  ash  of  the  fiber  also  shows  aggregates  of  calcium  carbonate, 
a  feature  which  distinguishes  it  from  jute. 

9.  Sansevieria  Fibers. — There  are  several  species  of  plants  of  the 
Sansevieria  group  which  are  used  for  fiber  purposes,  of  which  the  following 
are  the  principal  varieties:  Sansevieria  cylindrica,  known  as  Ife  hemp; 
it  occurs  in  South  Africa,  and  the  fiber  is  used  for  cordage.  It  is  said  to  be 
especially  adapted  for  cordage  used  in  deep-sea  soundings.  S.  guineensis, 
known  as  African  bowstring  hemp,  is  grown  in  Guinea  and  in  tropical 
America.  The  fiber  somewhat  resembles  Manila  hemp  and  is  used  for 
cordage.  ;S.  kirkii,  known  as  Pangane  hemp;  it  grows  on  the  mainland 
opposite  the  island  of  Zanzibar;  the  fiber  is  very  long  and  is  used  exten- 
sively by  the  natives.  S.  longiflora,  known  as  Florida  bowstring  hemp; 
the  fiber  is  strong  and  of  very  desirable  qualities,  and  is  said  to  be  superior 
to  sisal  hemp.  It  is  sufficiently  fine  to  be  employed  as  a  spinning  fiber. 
S.  roxburghiana  is  grown  in  India,  where  it  is  known  as  Moorva.     It  gives 


834 


MINOR   VEGETABLE   FIBERS  AND   PAPER   FIBERS 


the  true  "  bowstring  hemp,"  as  the  fiber  is  highly  prized  by  the  natives 
for  bowstrings  on  account  of  its  great  strength  and  elasticity.  »S.  zeylanica 
is  a  species  cultivated  in  Ceylon.  The  fiber  is  shorter  than  other  varieties, 
but  is  largely  used  for  making  cordage,  mats,  and  coarse  cloth. 

The  Sansevieria  fibers  are  all  obtained  from  the  leaves  of  the  plants; 
these  vary  in  length  from  2  to  9  ft.  The  commercial  fiber  consists  of  a 
bundle  of  filaments.  The  fiber  elements  have  a  length  of  about  2  mm. 
and  a  diameter  of  about  20  microns,  and  are  characterised  by  a  large  lumen. 
The  fibers  are  lignified  and  are  often  accompanied  by  spiral-shaped  cells 
of  parenchymous  tissue.  In  strength  and  durability  Sansevieria  fiber  is 
almost  equal  to  Russian  hemp.     The  fiber  of  S.  zeylanica  is  very  similar  to 

aloe  or  Mauritius  hemp, 
and  is  often  called  "  aloe 
hemp." 

10.  Tillandsia  Fiber. 
— This  fiber,  known  as 
Spanish  moss,  is  obtained 
from  Tillandsia  usneo- 
ides,  and  is  extensively 
employed  in  trade  as  a 
vegetable  horsehair,  as 
it  resembles  ver}^  closely 
the  animal  product  in 
general  appearance,  du- 
rability, and  elasticity. 
The  plant  grows  as  a 
parasite  on  tropical  trees, 
and  the  commercial  prod- 
uct  consists  of  the 
branched  stems.  It  is  of 
a  greenish  gray  color  and 
is  covered  with  soft  silvery-gray  scales.  The  fiber  is  composed  of  a  layer  of 
bast  in  which  are  imbedded  eight  fiber  bundles;  by  treatment  with  caustic 
alkali  solution  the  nucleus  (or  stripped  fiber)  is  easily  separated.  The 
stripped  fiber  has  a  jointed  appearance,  and  from  the  joints  side  branches 
often  issue.  According  to  Wiesner  the  commercial  fiber  never  has  natural 
ends;  the  color  varies  from  brown  to  lustrous  black.  The  diameter  between 
the  joints  varies  from  120  to  210  microns.  The  diameter  of  the  commercial 
fiber  is  from  0.3  to  0.5  mm.  Microchemical  color  reactions  cannot  be 
obtained  with  this  fiber  owing  to  its  dark  color.  Schweitzer's  reagent  has 
apparently  no  reaction.  According  to  Wiesner  the  fiber  of  vegetable  horse- 
hair has  9.0  percent  of  moisture  and  3.21  percent  of  ash. 

According  to  Hohnel,  the  Tillandsia  fiber  consists  of  the  many  fiber- 


FiG.  352. — Sansevieria  Fiber.     (Herzog.) 


TILLANDSIA  FIBER 


835 


bundles  growing  out  of  the  young  sprouts  of  the  plants;  it  does  not  consist 
of  air-roots,  but  of  branches  which  have  numerous  leaves  and  small  twigs. 
In  the  center  of  the  branch,  which  is  0.3 
to  0.5  mm.  thick  and  whose  nodes  are  5  to 
10  cm.  (mostly  6  to  7  cm.)  long,  lies  a  scleren- 
chymous  rope  with  the  vascular  bundles; 
it  is  from  this  that  the  fibers  are  derived. 
It  consists  of  a  ground-mass  of  rough,  long, 
sclerenchymous  elements,  of  which  the  inner 
are  light  brown,  and  the  outer  are  dark 
brown.  The  former  are  short  and  thin,  and 
8  to  12  microns  wide,  while  the  latter  are 
15  to  18  microns  wide  and  on  an  average  1.4 
mm.  long,  though  sometimes  they  also  occur 
very  short  and  only  2  to  3  mm.  long.  In  this 
firm  matrix  are  imbedded  8  vascular  bundles, 
which  consist  of  spiral,  network,  and  ring- 
shaped  fibers,  thin-walled,  colorless,  woody 
parenchym,  and  cambium  cells.  Sieve-like 
rods  appear  to  be  lacking.  Here  and  there, 
however,  may  be  seen  a  kind  of  parenchymous 
rind  with  the  epidermis  i-esting  on  the  fibers. 
This  epidermis  is  highly  characterised  by  its 
shell-shaped  hair  scales;  these  are  made  up  of 
a  single-cell  layer,  out  of  which  grows  a  many- 
celled  minute  hair.  The  very  thick  outer  walls  do  not  permit  a  trace  of 
cuticle  to  be  observed.     The  scales  are  the  organs  of  the  plant  for  the 


Fig.  353. — Fiber  from  Sansevi- 
eria.  (X325.)  e,  Ends;  I, 
longitudinal  view;  q,  cross- 
section;  r,  fissure-like  pores  in 
cell-walls.     (Hohnel.) 


Fig.  354. — Decorticating  Machine  for  Sansevieria  Fiber. 


absorption  of  water  which  roots  do  not  have,  but  which  are  found  on  the 
twigs  of  plants. 


836  MINOR  VEGETABLE   FIBERS  AND   PAPER  FIBERS 

11.  Solidonia  Fiber. — This  is  the  name  given  to  a  vegetable  fiber 
brought  out  in  Germany  as  a  wool-substitute.  It  is  supposed  to  be  a 
fiber  derived  from  an  African  plant  similar  to  China  grass,  and  it  seems 
to  be  very  similar  to  ramie.  It  is  a  very  fine  fiber  and  has  a  screw-shaped 
form  which  makes  it  somewhat  resemble  wool.  The  length  of  the  fibers 
varies  from  2|  to  4  ins.  in  length  in  medium  grades,  while  the  finer  grades 
reach  a  length  of  6  ins.  According  to  Valdenaire,  the  solidonia  fiber 
when  examined  under  the  microscope  shows  filaments  having  branches 
and  striations,  and  also  has  a  large  central  canal  or  lumen  of  a  yellow  color. 
The  Vetillard  reagent  colors  the  fibers  a  greenish  red,  inclined  to  a  violet. 
The  fibers  obtained  from  the  nettle,  which  are  somewhat  similar  to  soli- 
donia, are  stained  blue  by  the  same  reagent.  In  the  raw  state  solidonia 
is  of  a  gray  color,  similar  to  flax,  but  is  bleached  very  easily.  It  acts  the 
same  as  cotton  in  the  presence  of  dyestuffs  and  the  dyeing  operation  is 
the  same.  The  property  possessed  by  solidonia  of  absorbing  perspira- 
tion without  creating  a  sensation  of  cold  on  the  skin,  enables  it  to  be 
mixed  with  wool  to  advantage  in  the  manufacture  of  knit  goods. 

Solidonia  is  converted  into  yarn  by  either  the  carded  woolen  or  worsted 
process  and  is  spun  by  the  worsted  process  not  finer  than  36's  (cotton 
count).  Up  to  the  present  time  the  material  has  been  used  for  knit  goods, 
passementerie,  in  mixtures  with  short  wool  for  dress  goods  and  cheviots 
and  in  mixtures  with  long  wool  for  imitation  worsted. 

In  Germany,  solidonia  gained  a  wide  field  of  use  on  account  of  the 
shortage  of  wool  during  the  War.  As  a  substitute  for  linen,  solidonia 
has  been  used  in  Germany  for  the  manufacture  of  table  linen  of  beauty 
and  strength.  It  has  also  been  used  for  machine  belting.  German 
hosiery  and  underwear  mills  have  produced  from  it  socks  and  stockings 
which  are  difficult  to  tear,  and  unshrinkable  under  wear,  and  sporting 
jackets  of  fine  quality  and  strength. 

The  German  woolen  mills  have  manufactured  an  army  cloth  com- 
posed of  75  percent  wool  and  25  percent  sohdonia,  which,  it  is  asserted, 
surpasses  in  tensile  strength  any  pure  wool  cloth.  Similar  results  are 
claimed  with  respect  to  papermakers'  felts,  which,  with  a  percentage  of 
solidonia  mixture,  show  a  considerable  increase  in  strength.  Furthermore, 
women's  and  men's  clothing  composed  of  half  sohdonia  and  half  wool  or 
shoddy,  especially  in  piece-dyed  goods,  have  found  a  ready  market.  In 
textile  circles  in  Germany  it  is  declared  that  there  is  an  unlimited  field 
for  the  use  of  this  fiber.  Previous  to  the  War  the  price  of  solidonia  in 
Germany  was  two-thirds  the  cost  of  good  staple  wool. 

12.  Fiber  of  Sea  Grass. — This  is  the  fiber  of  Zostera  marina,  a  sea- 
weed or  grass  which  is  to  be  found  extensively  on  the  seacoast  of  temper- 
ate climates.  The  available  fibers  are  from  1  to  2  ft.  in  length,  and  con- 
sist of  bundles  of  3  to  6  elements.     The  latter  are  about  3  mm.  in  length. 


RAPHIA 


837 


with  a  diameter  of  about  6  microns,  hence  they  are  of  great  fineness. 
They  apparently  consist  of  pure  celullose. 

The  giant  seaweed  (Macrocystis  pyrifera)  may  also  be  used  as  a  fiber, 
this  seaweed  reaches  great  lengths,  sometimes  as  much  as  700  ft.  and  vast 
masses  are  often  thrown  up  on  exposed  coasts.  It  is  not,  strictly  speaking, 
a  fiber  plant  but  is  locally  employed  for  the  making  of  rough  cordage  and 
fishing  lines;  it  has  great  strength  and  is  very  durable. 

13.  Raphia.^ — This  fiber  is  obtained  from  the  cuticle  of  the  leaves 
of  the  raphia  palm  (Raphia  ruffia),  which  grows  extensively  in  Africa. 
The  leaves  are  very  long,  the  average  being  about  25  ft.     The  fiber 


— E 


Fig.  355. — Raphia  Fibers. 


(X300.)     E,  Showing  spoon-like  end.     (Micrograph  by 
author.) 


occurs  in  the  form  of  flat  straw-colored  strips,  3  to  4  ft.  in  length  and 
about  ^  in.  in  width;  from  these  ribbons  (which  are  largely  used  for 
plaited  textiles)  the  individual  fibers  may  be  separated  as  fine  filaments. 
The  fiber  elements  are  about  1.7  mm.,  in  length  and  14  microns  in  diameter. 
Under  the  microscope  the  surface  of  the  fiber  appears  irregular,  owing  to 
the  occurrence  of  fragments  of  parenchymous  tissue.  The  lumen  is 
about  one-fifth  the  diameter  of  the  fiber.  With  iodine  and  sulfuric  acid 
the  fiber  gives  a  yellow  coloration;  with  chlor-iodide  of  zinc  a  similar 
color;  with  phloroglucinol  and  hydrochloric  acid  a  reddish  coloration. 
Schweitzer's  reagent  causes  an  irregular  swelling  of  the  fiber. 
^  Sometimes  spelled  "raflBa." 


838 


MINOR  VEGETABLE   FIBERS  AND   PAPER  FIBERS 


A  fiber  somewhat  resembling  raphia  in  its  ribbon-like  appearance  is 
that  from  the  Great  Macaw  Palm  (Acroniia  lasiospatha) .  In  Brazil  it  is 
known  as  Mucuja,  and  in  Cuba  as  Pita  de  corojo.  According  to  Morris, 
the  fiber  is  firmer  than  raphia  and  not  so  papery;  it  is  extremely  strong 
and  is  capable  of  being  divided  into  very  tough  filaments.  Dodge  states 
that  the  ribbons  are  very  white  and  by  rolling  between  the  hands  may  be 
broken  up  into  innumerable  filaments  of  great  fineness.  One  drawback 
to  its  use  is  the  presence  of  little  spines,  as  sharp  as  needles  and  about 
half  an  inch  in  length.  In  Cuba  the  fiber  is  used  for  cordage,  and  is  said 
to  be  equal  to  henequen,  from  which  it  can  hardly  be  distinguished. 


Fig.  3.56. — Fibers  oi  Br omelia  karatas.     (X300.)     (Micrograph  by  author.) 


Another  variety  is  the  Acromia  sderocarpa  or  Gru  gru,  the  fiber  of  which 
is  distinguished  by  remarkable  fineness  and  softness. 

14.  Bromelia  Fibers. — The  Bromelia  is  a  genus  of  plants  having  very 
short  stems  and  densely  packed,  rigid,  lance-shaped  leaves,  the  margins 
of  which  are  armed  with  sharp  spines ;  they  are  natives  of  tropical  America, 
though  also  found  in  other  tropical  countries.  The  principal  species 
which  yield  fiber  are  the  following:  B.  karatas,  B.  yiriguin,  B.  argentina, 
B.  fastuosa,  B.  sagenaria,  B.  sylvestris,  and  B.  serra.  In  Mexico  the 
Bromelia  is  cultivated  in  parts  as  a  textile  plant  and  a  fiber  is  obtained 
from  it  which  is  described  as  very  fine  and  from  6  to  8  ft.  in  length.  By 
reason  of  its  fineness  and  toughness,  it  is  used  for  making  belts,  and  such 


BROMELIA  FIBERS  839 

fabrics  as  bagging,  wagonsheets,  carpets,  and  also  for  cordage,  hammocks, 
etc.  The  B.  pinguin  ^  is  perhaps  the  best  known  of  this  class  of  fiber 
plants,  and  it  is  known  as  the  wild  pineapple;  it  is  often  mistaken  for  an 
allied  species,  the  B.  sylvestris,  and  many  writers  have  confused  both  of 
these  varieties  with  the  fiber  of  the  common  pineapple.  The  wild  pine- 
apple fiber  mentioned  by  Morris  (of  the  Kew  Gardens)  as  B.  pita  is  really 
B.  karatas. 

The  B.  argentina,  known  as  caraguata,  is  an  allied  species  which  is 
found  in  Argentina  and  Paraguay;  its  structural  fiber  is  soft  and  silky 
and  resembles  pineapple  fiber,  occurring  in  lengths  of  from  4  to  6  ft.  and 
of  medium  strength.  The  B.  sylvestris  ^  gives  a  structural  fiber  which  is 
very  long,  creamy- white,  fine,  and  silky;  it  is  used  in  Central  America 
for  making  hunting  pouches  and  finely  woven  textures.  The  name  of 
"  silk  grass  "  and  "  silk  grass  of  Honduras  "  has  been  given  to  this  species, 
but  this  is  a  rather  indiscriminate  name  and  is  applied  to  a  number  of 
widely  differing  fibers.  Some  writers  also  refer  to  this  fiber  as  the 
"  istle  "  or  "  ixtle  "  of  Mexico.  This  variety  is  also  given  the  name 
Karatas  plumieri,^  and  is  commonly  known  as  Mexican  fiber,  Honduras 

1  Dr.  Baker  gives  the  botanj'  of  B.  pinguin  as  follows:  Acaulescent;  leaves  100  or 
more  in  a  rosette,  ensiform,  stiffly  erect  in  the  lower  half,  reaching  a  height  of  5  or 
6  ft.,  1|  to  2  ins.  broad  at  the  middle,  tapering  gradually  to  the  point,  green  and 
glabrous  on  the  face,  thinly  white-lepidote  on  the  back,  armed  with  very  large-toothed 
pungent  brown  prickles;  peduncle  stout,  stiffly  erect,  about  a  foot  long,  its  leaves 
often  a  bright  red;  panicle  dense,  stiffly  erect,  1  to  2  ft.  long;  axis  and  branches 
densely  mealy;  branch-bracts  oblong,  pale,  lower  with  a  rigid  spine-edged  cusp; 
lower  branches  3  to  4  ins.  long,  bearing  6  to  8  sessile  flowers;  flower-bracts  minute, 
ovate;  ovary  cylindrical,  very  pubescent,  about  an  inch  long;  sepals  nearly  as  long, 
with  a  densely  matted  tip;  petals  reddish,  densely  matted  at  the  tip  with  white  tomen- 
tum,  about  1^  ins.  longer  than  the  calyx;  berry  ovoid,  yellowish  brown,  1  in.  in 
diameter. 

2  Dr.  Baker  gives  thi'  following  description  of  the  botany  of  B.  sylvestris:  Acaules- 
cent; leaves  ensiform,  rigid,  3  to  4  ft.  long,  Ih  ins.  broad,  low  down,  narrowed  gradually 
to  the  point,  bright  green  on  the  face,  thinly  albo-lepidote  on  the  back,  armed  with 
strong-hooked  prickles;  peduncle  a  foot  or  more  long,  its  leaves  reflexing,  the  upper 
bright  red;  inflorescence  a  narrow  panicle  with  short  spaced-out  corymbose  branches, 
all  subtended  by  bright,  red  bracts,  the  lower  with  rigid  spine-edged  tips;  ovary 
pubescent,  cylindrical-trigonous,  about  an  inch  long;  sepals  nearly  as  long  as  the 
ovaries;  petals  reddish,  not  matted  at  the  tip,  protruding  j  in.  from  the  calyx. 

'  The  botany  of  Karatas  phimieri  is  described  as  follows :  Acaulescent ;  leaves  30 
to  40  in  a  dense  rosette,  rigid,  spreading,  ensiform,  4  to  8  ft.  long,  |  to  2  ins.  broad, 
low  down,  narrowed  gradually  to  the  tip,  green  and  glabrous  on  the  face,  persistently 
white-lepidote  and  finely  lineate  on  the  back,  armed  with  large  pungent-hooked  mar- 
ginal prickles;  flowers  about  50  in  a  dense  sessile  central  capitulum,  at  first  3  to  4  ins., 
finally  6  to  8  ins.  in  diameter,  surrounded  by  reduced  ensiform  inner  leaves  tinged 
with  red;  flower-bracts,  scariose,  oblanceolate,  2^  to  3  ins.  long;  ovary  cylindrical- 
trigonous,  I2  ins.  long,  clothed,  like  the  bracts  and  sepals,  with  loose  brown  tomentum; 
sepals  linear,   permanently  erect,   an  inch  long;    petals  reddish,  glabrous,   exserted 


840  MINOR   VEGETABLE   FIBERS  AND   PAPER   FIBERS 

silk-grass,  and  wild  pineapple.  The  plant  grows  throughout  tropical 
America,  and  the  fiber  is  obtained  from  the  leaf  which  grows  to  a  length 
of  8  to  10  ft.  and  is  armed  with  recurved  teeth  or  spines.  This  fiber  has 
been  much  confused  with  that  of  Bromelia  sylvestris.  The  fiber  appears 
to  be  used  locally  only  for  nets,  cordage,  sacking,  etc.  The  fiber  varies 
in  quality  according  to  the  age  of  the  plant,  that  from  the  young  leaves 
being  fine  and  white,  while  the  older  leaves  give  coarser  fiber.  It  has 
been  pronounced  by  some  as  being  superior  to  Russian  flax  as  a  textile 
fiber. 

15.  Piassava. — This  fiber  is  obtained  from  the  piassava  palm,  growing 
chiefly  in  Brazil.  There  are,  however,  two  varieties  of  piassava;  the 
Brazilian  is  obtained  from  the  leaves  of  Attalea  funijera,  while  the  African 
is  obtained  from  the  leaves  of  the  wine  palm,  or  Raphia  vinifera}  In 
Brazil  the  piassava  fiber  is  extensively  used  for  the  making  of  ropes,  sails, 
and  mats.  At  the  present  time  it  is  also  largely  used  in  Europe  for  the 
manufacture  of  brushes,  it  being  of  the  nature  of  a  bristle,  yet  very  flexible. 
The  commercial  fiber  from  Brazil  has  a  length  often  as  much  as  6  ft.; 
according  to  Wiesner  the  breadth  of  the  fiber  is  0.8  to  3.5  mm.  The 
color  varies  from  light  to  dark  brown.  The  individual  bast  cells  are  0.3 
to  0.9  mm.  in  length.  Stegmata  are  often  observed  in  the  periphery,  and 
on  treatment  with  chromic  acid  the  silicious  matter  is  left  in  characteristic 
star-shaped  residues.  According  to  Greilach  air-dried  piassava  contains 
9.26  percent  of  moisture,  and  Wiesner  found  the  ash  to  be  0.506  percent. 

African  piassava  has  less  elasticity  than  the  Brazilian  product,  and 
hence  is  of  lower  value.  In  cross-section  under  the  microscope,  the 
Brazilian  fiber  shows  an  aggregate  of  bundles,  whereas  the  African  piassava 
consists  of  a  single  filament.    The  commercial  African  fiber  has  a  length 

\  to  \  in.  beyond  the  tip  of  the  sepals,  united  in  a  tube  toward  the  base;  fruit  3  to 
4  ins.  long,  1  in.  diameter,  pale  yellow,  with  an  edible  white  pulp,  tapering  from  the 
middle  to  both  ends;  seeds  globose,  dull  brown,  vertically  compressed,  g  in.  diameter. 
1  Coarse  fibers  occur  in  trade  which  are  derived  from  a  number  of  palms.  They 
are  employed  partly  as  stuffing  materials  and  partly  for  the  making  of  brushes.  To 
these  fibers  belong:  (1)  Piassave  (Monkey  grass,  Paragrass,  Piassaba)  which  is  the 
fiber  from  the  leaves  of  Attalea  funifera  in  South  America.  It  is  coarse,  0.8-2.5  mm. 
thick,  and  is  used  for  brushes,  brooms,  ropes,  etc.  (2)  The  palmetto  fiber  from 
Chamacrops  humilis  (crin  vegetal,  crin  d'afrique)  in  North  America;  prepared  by 
splitting  up  the  leaves;  it  is  a  grass-like  material,  and  is  used  for  packing  and  stuffing. 
(3)  Fiber  of  the  date  palm,  from  Pha;nix  dactylifera;  from  the  leaves;  the  fiber  is  light 
yellow  in  color,  thick  and  stiff.  (4)  Talipot  fiber  from  Conjphce  umbracidifera  in  India. 
(5)  Raffia  straw,  the  epidermis  of  the  leaf  shank  of  Raphia  tcedigera;  used  for  twine 
and  basket  work;  it  consists  of  white,  thin  bands  with  turned-in  edges.  (6)  Ejon  or 
Gormito,  from  Arenga  sacchariffra;  used  in  India  for  cordage;  it  is  very  similar  to 
the  (7)  Ktool  or  Siam  fiber  from  Caryota  wens;  a  coarse,  almost  black  fiber,  used 
for  brushes.  (8)  The  black  horsehair-like  fibers  from  Bactris  tonientosa  and  other 
palms;  used  for  packing  (Hohnel). 


PIASSAVA  ■    841 

of  about  60  cms.  and  a  breadth  of  1  to  3  mm.  (Wiesner) .  Tho  color  varies 
from  pale  yellow  to  dark  brown.  The  stegmata  resemble  those  on  the 
Brazilian  fiber  but  are  larger. 

The  Brazilian  piassava  fiber  is  obtained  from  the  dilated  base  of  the 
leaf  stalks,  which  separates  into  a  long  coarse  fringe.  The  fiber  is  stiff, 
wiry,  and  of  a  bright  chocolate  color.  According  to  a  circular  of  Ide  & 
Christie  (London  fiber  brokers),  all  of  the  harsher  commercial  brush 
fibers  are  classified  under  "  piassava,"  the  following  forms  being  recog- 
nised: Brazilian,  Bahia  {Attalea  funijera) ,  and  Para  {Leojpoldinia  piassaba); 
kitool  from  Ceylon  {Caryota  urens);  Palmyra  also  from  Ceylon  {Borassus 
flabelifera);  West  Africa  {Raphia  vinifera);  and  Madagascar  (Dictyo- 
sperma  fibrosum) . 

Another  Brazilian  palm  fiber  that  has  attracted  considerable  attention 
is  that  from  the  Tecuma  palm  (Astrocaryum  tucuma) .  The  fiber  is  obtained 
from  the  young  leaves  and  is  readily  secured,  as  it  lies  just  under  the 
epidermis  of  the  leaf,  which  is  very  thin  and  may  be  easily  rubbed  off, 
leaving  the  fiber  clean  and  white.  It  is  claimed  that  in  strength  the  fiber 
is  equal  to  flax,  and  the  filaments  are  so  fine  that  it  has  been  given  the 
name  of  "  vegetable  wool."  It  is  used  in  Brazil  chiefly  for  the  making  of 
nets,  fish-lines,  and  hammocks.  Another  variety  which  is  often  confused 
with  the  foregoing  is  the  so-called  Tucum  thread  derived  from  the  unopened 
leaves  of  the  Tucum  palm.  It  is  a  fiber  of  great  strength  and  is  highly 
prized  for  the  making  of  bowstrings  and  fishing-nets  by  the  natives; 
it  is  laborious  to  extract  from  the  leaf,  however,  and  brings  a  high  price. 
The  natives  of  the  Upper  Amazon  make  very  beautiful  hammocks  of  fine 
tucum  thread,  knitted  by  hand  into  a  compact  web  of  so  fine  a  texture 
as  to  occupy  two  persons  for  several  months  in  their  completion  (Wallace) . 
The  fiber  is  fine,  resistant  and  durable,  of  a  yellowish  white  color  and  very 
elastic,  and  capable  of  absorbing  a  large  amount  of  water  (Dodge). 

Another  palm  fiber  that  is  employed  quite  extensively  in  the  East 
Indian  Islands  is  that  from  the  sago  palm  {Arenga  sacchartfera) .  It  is 
horsehair-like  material  found  at  the  base  of  the  leaves  and  is  the  gomuti 
fiber  or  Ejoo  of  the  Malays.  It  is  used  for  making  cordage,  brushes,  and 
for  upholstery.  According  to  Roxburgh,  ropes  made  from  the  black 
fibers  of  the  leaf  stalks  are  exceedingly  durable  under  water.  The  fiber 
is  as  elastic  as  coir  and  floats  on  water.     It  is  also  used  for  making  sandals. 

There  are  also  a  few  other  fibers  known  commercially  as  piassava, 
the  principal  one  of  which  is  obtained  from  Caryota  urens.  This  is  grown 
in  India  and  Ceylon  and  is  known  by  the  name  kitool  or  kittul.  It  is  a 
brownish  black  fiber,  and,  according  to  Dodge,  exhibits  considerable 
tenacity  and  will  bear  twisting.  The  finer  fibers  closely  resemble  horse- 
hair and  may  be  readily  curled.  When  employed  for  this  purpose  the 
fiber  is  combed  and  steeped  in  linseed  oil  to  make  it  more  pliable,  when 


842 


MINOR   VEGETABLE   FIBERS   AND   PAPER   FIBERS 


it  also  assumes  a  black  color.  It  is  sometimes  mixed  with  horsehair 
and  used  for  stuffing  mattresses  and  pillows.  The  chief  use  of  kittool 
fiber,  however,  is  for  the  making  of  brushes,  for  which  it  is  especially 
suited;  such  brushes  are  used  for  polishing  linen  and  cotton  yarns  and  for 
brushing  velvet.  In  Ceylon  the  fiber  is  also  used  for  making  ropes  of 
great  strength  and  durability  and  these  are  used  for  tying  elephants. 
Considerable  of  this  fiber  has  been  imported  into  the  United  States  where 
it  is  chiefly  used  for  making  brewers'  brushes. 

Crin  vegetal  is  also  a  palm  fiber  employed  as  a  substitute  for  horse- 
hair in  stuffing.     It  is  obtained  from  a  dwarf  palm  in  Algeria,  Chamarops 

humilis.  It  is  also  imported  under  the 
name  of  African  fiber.  The  plant  is  a 
species  of  palmetto  and  the  fiber  is  ob- 
tained by  shredding  the  leaves.  It  comes 
into  trade  in  the  form  of  a  loosely  twisted 
rope,  which  when  opened  up  gives  a 
crinkled  fiber  somewhat  resembling  hair. 
It  is  used  as  a  mattress  fiber. 

16.  Paper  Mulberry  Fiber. — With  re- 
gard to  its  textile  uses  this  fiber  is  rather 
unusual  in  that  it  is  employed  by  the 
natives  of  the  South  Sea  Islands  for  the 
preparation  of  a  fabric  directly  without 
spinning  into  yarn  or  weaving.  The  plant 
from  which  it  is  derived  is  a  small  tree 
known  as  Broussonetia  papyrifera  and  the 
fabric,  known  as  tapa  (or  kapa  and  also 
known  as  mast  in  Fiji)  is  made  from  the 
bast.  This  fabric  is  a  very  fine  white 
cloth  and  the  method  of  its  preparation 
is  rather  curious;  the  cleansed  fibers  are 
laid  out  so  as  to  form  a  regular  and  even 
Fig.  357. — Paper  Mulberry  Fiber,  surface,  several  layers  being  laid  down  wet 
Showing  d,  twists;  v,  cross-  and  allowed  to  dry  overnight.  They  will 
mark;   /,  lumen.    (Hohnel.)  j^^^ere  SO  that   the   entire   mass   may  be 

lifted  as  one  piece.  This  web  is  then 
laid  on  a  smooth  plank  and  beaten  with  a  wooden  instrument  until 
it  is  spread  out  and  matted  together  in  a  strong  web  as  fine  as  muslin. 
Pieces  may  be  webbed  together  in  a  remarkable  manner.  In  the  Kew 
Museum  is  a  part  of  such  a  fabric  from  the  Friendly  Islands  said  to  be 
originally  120  ft.  wide  and  2  miles  long.  Some  varieties  of  tapa  cloth 
are  made  quite  thick  and  resemble  tough  wash  leather.  The  material 
may  be  readily  dyed  and  printed  and  is  easily  bleached  to  a  good  white. 


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PERINI  FIBER  843 

The  paper  mulberry  also  grows  very  extensively  in  Japan  where  the 
fiber  is  used  for  the  making  of  paper.  A  kind  of  cloth  is  also  made  in 
Japan  from  this  paper,  the  paper  being  cut  into  strips  which  are  twisted 
into  a  yarn  and  used  as  the  filhng  of  the  fabric,  the  warp  consisting  of 
hemp  or  silk. 

According  to  Hohnel  the  fiber  of  the  paper  mulberry  is  about  6  to  15  mm. 
long  and  about  25  to  35  microns  thick,  though  two  kinds  of  fibers  are 
usually  present,  thick  and  thin.  The  fiber  is  mostly  thick-walled  and  is 
sometimes  twisted  somewhat  like  cotton.  The  lumen  is  small  and  dif- 
ficult to  distinguish,  though  at  intervals  it  is  filled  with  a  yellowish  material. 
In  the  ribbon-shaped  fibers  the  ends  are  broad  and  rounded,  while  in  the 
thick  fibers  the  ends  are  smaller  and  tend  to  be  sharply  pointed.  The 
fibers  often  show  the  presence  of  small  prismatic  crystals  of  calcium 
oxalate  (Fig.  357). 

17.  Perini  Fiber. — This  is  a  fiber  obtained  from  a  plant  indigenous 
to  Brazil,  and  known  as  Canhamo  braziliensis  perini,  being  named  from 
its  discoverer  Victorio  Antonio  de  Perini,  who  found  it  in  its  wild  state  in 
the  forests  of  Brazil.  He  studied  its  culture  and  practical  value  as  a  fiber 
for  textiles  and  paper  and  received  a  U.  S.  patent  for  it  in  1904.  The 
plant  is  virtually  a  weed,  growing  from  12  to  18  ft.  high  in  four  to  five 
months,  and  resembles  hemp  in  general  appearance.  It  was  known  as 
Brazilian  linen  and  was  once  held  forth  as  a  possible  competitor  for  linen. 
The  plants  grown  for  fiber  should  be  cut  before  flowering,  and  require 
about  three  months  to  attain  the  proper  growth  of  10  ft.  They  are  cut 
down  about  4  ins.  from  the  ground,  and  immediately  send  out  shoots, 
which  can  be  cut  in  the  same  manner  again.  In  this  way  three  crops 
may  be  obtained  each  year,  after  which  the  roots  are  dug  up  and  seed 
sown  for  a  fresh  crop.  The  plant  is  hardy,  resisting  alike  the  dry  and  the 
rainy  season,  and  is  not  a  prey  to  insects  or  mildew.  The  fiber  which  is 
obtained  from  the  bast  is  of  excellent  quality  and  closely  resembles  flax, 
being  long,  fine,  strong  and  flexible,  and  easily  adapted  to  bleaching  and 
dyeing.  Its  luster  is  also  quite  high  and  the  color  is  good.  The  fiber  is 
easily  decorticated  from  the  stem  of  the  plant  and  does  not  require  a  ret- 
ting operation,  but  may  be  stripped  entirely  by  mechanical  processes. 
The  perini  fiber  is  cultivated  to  a  considerable  extent  in  Brazil  and  is 
employed  in  textile  manufacturing  in  that  country.  If  properly  organised 
the  industry  of  growing  this  fiber  should  be  capable  of  great  extension 
so  that  the  fiber  could  be  suitably  prepared  for  the  American  and  Euro- 
pean market  as  a  fiber  to  compete  with  linen  and  hemp.  Attempts  have 
been  made  to  develop  the  perini  fiber  business  in  the  United  States  with 
the  idea  of  employing  the  entire  stem  of  the  dried  plant  as  a  paper  making 
material.  Some  of  the  fiber  has  been  quite  successfully  grown  in  the 
south,  but  as  yet  sufficient  interest  does  not  seem  to  have  developed  to 


844 


MINOR   VEGETABLE   FIBERS   AND   PAPER   FIBERS 


carry  on  the  cultivation  of  it  on  a  large  scale.  The  present  author  has 
examined  samples  of  this  fiber  and  has  tested  them  out  in  various  ways, 
which  leads  him  to  the  conclusion  that  the  bast  fiber  could  be  employed 
in  the  textile  industries  as  an  excellent  substitute  for  flax.  It  is  said 
that  about  3000  lbs.  of  fiber  can  be  obtained  per  acre  for  each  cutting 
of  the  plant. 

18.  Couratari  Fiber. — This  is  a  bark  fiber  employed  rather  exten- 
sively by  the  natives  in  South  America  to  make  a  crude  cloth  for  their 
rough  clothing.  Orton  states  that  the  natives  make  a  bark  cloth  from  the 
Tururi  or  Couratari  legalis.  The  plant  is  a  small  tree  with  a  white  bark 
from  which  single  pieces  of  fabric  may  be  taken  up  to  4  yds.  in  length. 
The  cloth  resembles  a  coarse  woolen  fabric  composed  of  two  layers  of  wavy 
fiber.     A  similar  fabric  is  made  from  the  Tauary  tree  {Couratari  tauari) 


Fig.  358.— Peat  Fiber.     (Herzog.) 


of  Brazil.  This  is  a  larger  tree  from  the  interior  bark  of  which  thin  lay- 
ers of  fabric  are  extracted,  appearing  like  thin  paper.  It  is  much  used 
for  wrapping  cigarettes  and  cigars  and  as  a  rough  clothing  and  bedding 
for  the  natives.  Blankets  made  from  it  resemble  soft  pliable  leather. 
Some  of  the  Indians  of  Peru  and  Bolivia  make  shirts  of  the  fabric  and  dye 
them  in  various  colors.  The  Couratari  guianensis  of  Guiana  also  pro- 
duces a  similar  textile  fiber  that  is  used  for  many  purposes. 

19.  Peat  Fiber. — The  fiber  obtained  from  certain  varieties  of  peat 
has  been  utilised  for  textile  purposes  in  Europe.  It  is  usually  mixed 
with  wool  shoddy  or  other  low-grade  fibers  to  make  coarse  yarns.  The 
so-called  "  Geige  "  process  for  manufacturing  peat  wool  consists  in  first 
stirring  the  dried  peat  in  a  bath  of  weak  soda  for  several  hours  to  remove 
the  humic  compounds.  It  is  then  dried  and  passed  through  opening 
machines,  and  afterwards  subjected  to  a  process  of  fermentation.     The 


TEXTILE  YARNS   FROM   WOOD-PULP  845 

fiber  is  then  treated  to  a  number  of  processes  of  extraction,  washing 
and  souring,  and  finally  bleached.  The  product,  which  averages  about 
15  cm.  in  length,  is  said  to  be  excellent  for  the  preparation  of  surgical 
bandages  as  it  is  highly  absorbent.  It  may  also  be  spun  with  50  percent 
of  wool  to  give  textile  yarns.^ 

According  to  Linsbauer  the  fiber  of  peat  is  mostly  derived  from  the 
leaf  bast  of  various  kinds  of  Eriophorum.  The  length  of  the  fiber 
elements  varies  between  0.323  and  2.304  mm.,  the  majority,  however, 
being  less  than  1  mm.  The  diameter  varies  between  4.9  and  9.9  microns 
and  the  fiber  has  a  long  spindle-shaped  form.  It  shows  a  broad  and 
distinct  lumen  somewhat  similar  to  jute,  and  the  cell- wall  has  often  a  wavy 
appearance.  When  treated  with  phloroglucinol  and  hydrochloric  acid  the 
fiber  gives  a  red  color  showing  lignification.  When  treated  with  copper- 
ammonium  oxide  solution  the  fiber  turns  green  in  color  and  exhibits  a 
remarkable  sausage-like  swelling  somewhat  similar  to  cotton. 

20.  Textile  Yams  from  Wood-pulp. — There  is  at  present  a  consider- 
able industr}^  in  the  manufacture  of  yarns  for  twine  and  textile  fabrics 
from  wood-pulp.  The  wood-pulp  tissue  is  cut  into  narrow  strips  which 
are  then  twisted  on  special  machines  so  as  to  give  a  coarse  yarn.  These 
yarns  are  made  in  counts  from  5  to  10  (cotton  scale)  and  are  possessed  of 
sufficient  tensile  strength  and  elasticity  to  be  manufactured  into  a  wide 
variety  of  fabrics.  Used  alone,  these  wood-pulp  yarns  are  made  into 
floor  coverings,  bagging,  wall  covering,  and  various  ornamental  uphol- 
stery fabrics.  They  are  especially  adapted  as  a  substitute  for  jute  in 
such  uses,  for  though  they  have  not  the  tensile  strength  of  jute,  yet  they 
exhibit  great  resistance  to  wear  and  rubbing.^  When  woven  in  con- 
junction with  yarns  of  cotton,  linen,  jute,  etc.,  a  wide  variety  of  fabrics 
may  be  cheaply  produced. 

The  manufacture  of  yarns  from  wood-pulp  allows  of  the  utilisation 
in  the  purely  textile  industries  of  fibers  not  having  sufficient  length  to 
be  spun.  The  minimum  limit  of  economic  working  in  spinning  is  obtained 
with  fibers  of  3-5  mm.  length,  and  as  this  is  the  maximum  limit  in  the 
case  of  paper  making,  it  may  be  seen  that  by  converting  paper  into  tex- 
tile yarns  it  becomes  possible  to  utilise  for  the  latter  fibers  of  any  length. 

There  are  several  methods  now  in  use  for  the  manufacture  of  wood- 
pulp  yarns : 

1  There  has  been  considerable  investigation  in  Germany  on  the  subject  of  peat 
fiber.  See  Zeit.  f.  d.  Gesamte  Textilindnstne,  1899,  Nos.  5  and  7;  Kimststoffe,  1918, 
Nos.  9  and  11;  Dingl.  Polyl.  Jour.,  1900,  p.  437;  Haiisding,  Handbuch  der  Torfgemin- 
nung  und  Verarbeitung,  Berlin,  1904;  also  see  Ger.  Pnts.  .50,304,  96,540,  92,265,  102,988, 
150,698,  159,284,  162,108,  161,667,  161,668,  167,831,  168,172,  169,381,  180,397,  258,068, 
301,394,  301,396,  .307,765,  315,755. 

-  Paper  yarn  is  used  ako  as  a  substitute  for  jute  as  a  packing  between  the  armature 
of  lead  and  iron  in  electric  cables. 


846  MINOR   VEGETABLE   FIBERS  AND   PAPER  FIBERS 

(a)  The  Claviez  System  ^  makes  a  yarn  called  xylolin  from  a  finished 
but  unsized  paper.  The  paper  is  cut  into  strips  of  2-3  mm.  width,  which 
are  then  wound  on  separate  bobbins.  A  twisting  and  rolling  is  then 
given  the  paper  strip  ^  so  as  to  consolidate  it  into  a  compact  thread  or 
yarn.  The  yarn  is  then  moistened  and  again  twisted  and  rolled  to  produce 
a  more  solid  thread.     Textilose  is  a  similar  product  used  as  a  jute  substitute. 

(6)  The  Kellner-Tiirk  method  '^  starts  with  the  paper  sheet  in  the 
unfinished  condition  as  it  is  delivered  from  the  press-rolls  of  the  paper 
machine.  The  production  of  the  pulp  ribbons  is  effected  by  a  specially 
constructed  wire  cloth  consisting  of  a  gauze  alternating  with  flat 
strips  of  brass.  The  pulp  ribbons  are  then  rolled  and  twisted  into  a 
yarn.'* 

(c)  The  Kron  system  ^  produces  products  known  as  silvalin  yarns. 
The  pulp  web  is  divided  into  narrow  strips  by  fine  jets  of  water.  The 
entire  web  is  rolled  up  and  the  strips  afterward  separated  as  disks.  The 
pulp  strips  are  then  squeezed  between  press  rolls  for  the  gradual  removal 
of  water,  then  further  dried  on  steam-heated  cylinders.  The  strips  are 
next  wound  on  magazine  rolls  from  which  they  are  twisted  and  rolled 
into  yarns.  Silvalin  yarns  are  now  produced  in  large  quantities  in  Ger- 
many and  Russia  where  they  are  employed  as  substitutes  for  jute.  Licella 
yarn  is  a  similar  product  made  from  narrow  strips  of  wood-pulp  paper  as 
a  substitute  for  jute.*^ 

According  to  Pfuhl  •'  wood-pulp  yarns  have  an  average  breaking  length 
of  5  to  7  km.,  and  an  elasticity  of  6  to  7  percent  of  their  strength  when 
moistened,  but  when  woven,  into  fabrics  they  may  be  waterproofed  satis- 

^  Ger.  Pat.  93,324.     The  Claviez  method  was  worked  at  Jagenberg. 

2  In  order  to  spin  paper  yarns,  regulated  moistening  of  the  paper  is  necessary, 
and  therefore  some  means  of  measuring  the  rate  at  which  the  material  can  be  wetted 
is  desirable  (F.  Herig,  Papier-Fabrikant,  1921,  p.  32).  For  this  purpose,  two  pieces 
of  very  smooth  cardboard  are  stuck  together,  the  top  piece  having  a  hole  cut  in  it  in 
the  form  of  some  regular  figure.  The  cavity  is  filled  with  a  very  finely  powdered  dye, 
and  the  paper  to  be  tested  is  gently  pressed  on  the  surface  so  that  it  takes  up  a  thin 
film  of  the  dye.  Any  excess  of  the  pigment  is  shaken  off  and  the  paper  is  floated  on 
water  with  the  dusted  surface  uppermost.  As  the  paper  wets  through,  the  larger 
granules  of  dye  »how  up  like  pepper  and  then  two  waves  of  color  pass  over  the  dusted 
surface.  The  time  from  the  laying  down  of  the  paper  to  the  appearance  of  the  second 
wave  of  color  is  taken  as  a  measure  of  the  wetting  property  of  the  paper.  Mahogany 
Red  is  the  most  suitable  dye,  as  it  contrasts  well  with  the  color  of  the  wet  paper. 
Methyl  Violet  may  be  used  with  advantage  for  lightly-sized  papers  since  it  takes 
twice  as  long  to  develop  as  Mahogany  Red. 

^Ger.  Pats.  73,601,  and  76,126,  and  79,272.  The  Kellner-Tiirk  process  is  carried 
out  at  Altdamm,  Stettin. 

'Ger.  Pats.  140,011  and  140,012,  and  140,666. 

«  U.  S.  Pats.  762,914  and  794,516;    762,640  and  762,641;   795,776  and  776,474. 

8  Licella  yarn  is  made  by  the  Siiddeutschen  Jutefabrik. 

^  Pfuhl,  Pa  jrier  staff  game,  p,  101. 


TEXTILE   YARNS   FROM   WOOD-PULP 


847 


factorily.^  The  finished  fabric  has  about  one-half  the  strength  of  jute 
fabric  of  the  same  quahty  and  weight. 

The  size  or  count  of  wood-pulp  yarns  is  expressed  by  the  number  of 
meters  to  the  gram.  To  convert  this  into  the  cotton  count  (840  yds. 
per  lb.)  multiply  by  the  factor  0.691;  to  convert  into  the  line  count 
(300  yds.  per  lb.)  multiply  by  the  factor  1.654;  and  to  convert  into  the 
jute  count  (lbs.  per  14,400  yds.)  multiply  by  the  factor  29. 

The  manufacture  of  paper  yarns  and  textile  fabrics  therefrom  under- 
went a  tremendous  development  in  Germany  and  Austria  during  the 
recent  World  War.  The  paper  used  for  spinning  paper  yarns  is  almost 
entirely  made  from  wood-pulp.  The  yarns  are  made  from  long,  narrow 
strips  of  thin  paper,  which  can  be  loosely  or  tightly  twisted  or  "  spun." 
The   yarns    can    be 


made    of     v  a  ri  o  u  s 

thicknesses,  and  have 

now  been  employed 

for  weaving  a  great 

variety    of    fabrics. 

They  can  be  readily 

dyed  to  any  desired 

shade,    and    certain 

kinds  can  be  bleached 

to  a  snowy  whiteness. 

In  manufacturing  the 

yarns,  other  materials 

have  sometimes  been 

combined    with    the 

paper,   but    recently 

the     tendency    has 

been  to  make  them 

of  paper  only.     In  the  production  of  fabrics,  paper  yarns  are  sometimes 

woven  in  conjunction  with   other  yarns,  such   as  those  of  cotton,  flax, 

hemp,  and  jute. 

Among  the  chief  advantages  of  paper  yarns  are  the  low  cost  of  produc- 
tion, which,  at  any  rate  in  normal  times,  is  much  less  than  that  of  yarns 

'  For  the  waterproofing  of  paper  yarn  and  its  fabrics,  a  number  of  materials  have 
been  used,  but  the  best  method  seems  to  be  first  to  pass  the  yarn  through  a  bath  of 
gum,  tannin  and  siHcate  of  soda  at  50°  C,  and  then  through  a  cold  bath  of  basic 
formate  of  aluminium  having  a  density  of  about  6°  Be. 

Other  materials  that  have  been  used  include  a  treatment  with  gelatine,  after  which 
it  is  subjected  to  formaldehyde,  but  this  has  been  found  to  reduce  the  strength  and 
to  cause  the  strands  to  separate.  The  use  of  tannin  alone  produces  hardness,  though 
with  an  increase  in  strength.  Acetate  of  aluminium,  neutrahsed  with  sodium  car- 
bonate, gives  a  wrinkled  product. 


Fig.  359. — Twines  Made  from  Paper  Yarns. 


848  MINOR   VEGETABLE   FIBERS   AND   PAPER  FIBERS 

made  from  other  fibrous  materials,  and  the  cleanhness  of  the  manufacturing 
operations,  which  create  Kttle  or  no  dust. 

The  spinning  of  yarn  from  finished  paper  was  invented  by  Emil  Claviez, 
who  in  1895-97  took  out  patents  for  the  production  of  yarn  from  paper 
strips  and  a  spindle  for  the  purpose.  The  manufacture  of  this  yarn, 
which  is  known  as  ''  Xylolin,"  was  first  carried  on  in  Saxony  and  subse- 
quently in  Austria.  Claviez's  invention  has  formed  the  basis  of  all  the 
later  methods  of  spinning  paper. 

The  paper  used  for  the  manufacture  of  paper  yarns  may  be  made  of  any 
of  the  usual  raw  materials,  such  as  chemical  and  mechanical  wood-pulp, 
cotton  rags,  various  kinds  of  fiber  waste,  and  old  ropes,  etc.  In  most  cases, 
however,  the  paper  is  made  from  chemical  wood-pulp.  Wood-pulp  manu- 
factured by  the  digestion  of  wood  with  caustic  soda  (as  in  the  soda  and 
sulfate  methods)  is  regarded  as  superior  for  this  purpose  to  that  made 
b}^  the  sulfite  process,  and  is  said  to  yield  a  more  supple  and  flexible  paper. 

' '  Kraft  "  paper  is  considered  to  be  the  most  suitable  paper  for  spinning, 
and  has  been  found  to  furnish  yarns  20  to  25  percent  stronger  than  other 
kinds  of  paper.  Kraft  pulps  are  made  either  by  the  sulfate  or  the  soda 
process,  and  the  digestion  is  carried  out  under  such  conditions  that  the 
wood  is  not  completely  resolved  into  its  ultimate  fibers,  but  a  certain 
proportion  of  the  binding  material  remains.  Such  products  are  brown 
pulps,  which  do  not  bleach,  but  produce  remarkable  strong  paper,  which 
is  very  resistant  to  wear.  Pure  sulfite  paper  produces  serviceable  yarns, 
which  for  many  purposes  are  quite  satisfactory,  but  are  not  so  highly  val- 
ued on  account  of  their  being  less  elastic.  For  the  manufacture  of  specially 
fine  yarns,  tissue  paper  gives  the  best  results. 

The  paper  intended  for  spinning  is  packed  in  wide  rolls.  These  rolls 
are  placed  in  the  cutting-machine,  which  at  one  operation  cuts  the  whole 
width  into  strips  of  the  breadth  required,  usually  from  re  to  ^  in.  These 
strips  are  wound  on  to  narrow  disks  or  bol)bins,  and  are  then  twisted  on 
spinning  frames,  similar  to  those  employed  in  the  manufacture  of  jute 
and  cotton  yarns.  Before  being  twisted  the  strips  are  moistened  by 
being  led  over  a  damping  roller  which  dips  into  water  (or  a  solution  of 
some  substance  designed  to  increase  the  strength  of  the  paper).  The 
method  of  damping  the  strips  varies,  however,  in  different  types  of  ma- 
chinery. Jute-spinning  machinery  is  considered  more  adaptable  than 
cotton-spinning  machinery  for  making  paper  yarn,  the  latter  requiring 
greater  modification  to  render  it  suitable  for  the  purpose. 

In  the  process  employed  by  the  Textilite  Engineering  Company  of 
England  the  paper  in  rolls  30  ins.  wide  is  cut  by  machinery  into  strips 
varying  in  width  from  y^g  to  1  in.,  or  even  more.  The  paper  is  conveyed 
by  means  of  two  feed-rollers  to  another  pair  of  rollers,  each  provided  with 
cutting  disks,  which  are  so  arranged  that,  while  cutting,  they  are  auto- 


TEXTILE   YARNS   FROM   WOOD-PULP  849 

matically  sharpened.  The  strips  are  then  led  to  two  winding-on  rollers, 
one  taking  even-numbered  disks  and  the  other  odd-numbered  disks.  The 
disks  are  next  transferred  to  a  spinning  machine,  and  are  mounted  on 
uprights  over  the  middle  of  the  frame,  each  disk  being  provided  with  a 
light  spinning  brake  to  prevent  overrunning.  As  the  disks  contain  a  long 
length  of  strip,  they  provide  practically  a  lasting  feed  to  the  spinning-frame. 
Moisture  is  imparted  to  the  paper  by  passing  the  strips  first  over  a  guide- 
rod,  extending  the  length  of  the  machine,  and  then  over  a  roller  partly 
submerged  in  a  liquid  contained  in  a  trough.  The  strips  next  pass  over 
guide-pulleys,  and  are  then  spun  or  curled  and  wrapped  on  to  bobbins 
by  the  ring  and  traveler  method  on  the  long-lift  principle.  Each  spindle 
is  provided  with  a  hand-stop  motion.  The  machines  employed  in  sub- 
sequent operations  are  ahnost  identical  with  those  used  in  the  jute  and 
flax  trade.  The  yarns,  in  spools  of  weft  and  warp,  are  subsequently  trans- 
ferred to  the  looms,  in  which  they  are  woven  to  any  desired  pattern. 

The  3^arn  can  be  toughened  by  impregnation  with  size,  tannin,  alumin- 
ium formate,  or  sodium  silicate  (water-glass).  It  has  been  stated  that  the 
best  method  of  increasing  the  strength  of  paper  yarns  and  rendering  them 
more  resistant  to  moisture  is  to  pass  the  yarn  first  through  a  glue,  tannin, 
and  silicate  bath  at  120°  F.,  and  then,  without  previously  drying  it,  to  pass 
it  through  a  cold  bath  of  basic  aluminium  formate,  and  afterward  to  dry 
it.  The  yarn  when  thus  treated  is  found  to  have  its  tensile  strength  in- 
creased 10  percent  when  dry  and  30  percent  when  wet. 

The  dyeing  of  paper  textiles  is  effected  on  the  same  lines  as  cotton 
dyeing.  Substantive,  sulfur,  and  vat  dyestuffs  are  employed,  but  greater 
care  is  required  in  turning  and  handling  the  materials.  For  this  reason, 
the  use  of  dyeing  machines  is  preferable  to  dipping  by  hand;  the  baths 
must  not  be  too  strongly  alkaline,  and  the  temperature  should  be  kept 
below  the  boiling-point,  preferably  at  about  120°  to  140°  F.  Either  the 
fabric  or  the  yarn  may  be  dyed ;  but,  in  the  case  of  materials  to  be  used  for 
clothing,  it  is  necessary  to  dye  the  pulp  before  making  the  paper  in  order 
that  the  color  ma}^  completely  penetrate  the  material. 

Bleaching  may  be  effected  by  treating  the  yarn  or  fabric  with  a  dilute 
solution  of  bleaching-powder,  afterward  transferring  it  to  a  weak  acid  bath, 
and  finally  rinsing  well  with  water.  In  order  to  obtain  a  pure-white 
material,  it  is  usually  necessary  to  employ  paper  made  from  bleached  pulp. 

Paper  yarns  are  now  being  used  for  an  extremely  wide  range  of  pur- 
poses. One  of  the  principal  uses  is  for  the  manufacture  of  cordage,  ranging 
from  fine  twine  up  to  coarse  rope.  Paper  string  is  mostly  made  from 
paper  yarn  alone,  but  in  some  cases  the  paper  is  spun  on  a  central  core  of 
fine  hemp  twine,  and  in  other  cases  on  a  fine  metal  wire.  Another  impor- 
tant use  is  for  the  manufacture  of  sacks  and  bags  to  replace  those  made 
from  jute  and  hemp.     The  sacks  are  employed  for  various  kinds  of  produce, 


850  MINOR  VEGETABLE   FIBERS   AND   PAPER   FIBERS 

such  as  grain,  flour,  potatoes,  seeds,  coffee,  salt,  wool,  artificial  manures, 
and  cement,  and  possess  the  advantage  of  being  free  from  odor,  and 
having  no  loose  fibers  on  their  surface  which  could  become  mixed  with  the 
contents.  During  the  war  enormous  quantities  of  paper  yarn  have  been 
used  for  making  sandbags  for  army  purposes.  Experiments  which  have 
been  made  by  British  military  authorities  with  captured  German  sandbags 
have  shown  that  sandbags  made  entirely  of  paper  yarn  are  less  resistant 
than  those  of  jute,  and  are  more  liable  to  break  on  impact,  and  that  snow 
and  frost  have  a  deleterious  effect  on  them.  It  has  been  found,  however, 
that  sandbags  made  with  a  jute  warp  and  a  paper  weft  form  a  satisfactory 
substitute  for  jute  bags,  but  that  the  paper  weft  is  less  resistant  than  the 
jute  warp. 

Paper  yarns  are  also  employed  for  the  manufacture  of  braiding,  web- 
bing, tent  canvas,  waterproof  canvas,  tarpaulins,  mats,  upholstery,  and 
carpeting  materials,  wall  coverings,  as  a  foundation  for  linoleums  and 
oilcloths,  and  for  woven  boards,  which  are  said  to  form  a  suitable  substitute 
for  three-ply  wood.  Another  use  of  the  yarns  is  for  the  manufacture  of  a 
leather  substitute,  especially  for  machine  belting.  For  the  latter  purpose 
the  yarns  are  spun  from  parchment  paper,  and  are  afterward  impregnated, 
wound  on  spools,  and  woven  into  fabrics  which  are  stitched  together  to 
make  belting  of  the  required  thickness. 

Paper  yarns,  which  have  been  specially  impregnated,  are  stated  to  be 
used  in  the  cable  industry,  chiefly  as  a  partial  or  complete  substitute  for 
jute  as  a  packing  between  the  lead  sheath  and  the  iron  armor  of  the  cables. 
In  the  coating  of  lead-sheathed  cables  with  waterproof  composition,  the 
winding  of  paper  yarn  is  as  eflScient  as  the  old  jute  winding,  since  it  adheres 
better  to  the  lead  sheath,  and  blends  with  the  composition  to  form  a 
perfectly  flexible  and  waterproof  covering. 

For  the  purposes  mentioned  above,  the  paper  yarn  is  chiefly  used  in 
place  of  jute;  but  it  is,  of  course,  obvious  that  the  products  of  its  manu- 
facture cannot  possess  properties  equal  to  those  of  materials  made  from 
jute.  Many  references,  however,  have  been  made  in  the  foreign  press  to 
the  utilisation  of  such  yarn  as  a  substitute  for  cotton  yarns,  but  it  seems 
very  doubtful  if  its  use  in  this  direction  can  be  readily  satisfactory  except 
as  a  temporary  makeshift. 

21.  Paper  Fibers  and  their  Examination. — Although  paper  is  related 
to  a  rather  separate  industry  than  that  of  textiles,  nevertheless,  as  shown 
in  the  preceding  section,  the  two  somewhat  closely  approach  each  other 
in  certain  particulars,  so  that  it  becomes  almost  impossible  to  entertain 
a  detailed  discussion  of  textile  fibers  without  at  the  same  time  encroaching 
somewhat  on  the  field  of  paper  fibers.  It  is  therefore  considered  proper 
at  this  point  to  introduce  a  brief  description  of  these  fibers  together  with 
some  discussion  as  to  their  examination  and  determination.     The  fibers 


PAPER   FIBERS   AND  THEIR  EXAMINATION 


851 


which  may  be  used  in  the  manufacture  of  paper  are  very  numerous,  but 
are  almost  entirely  confined  to  the  class  of  vegetable  materials,  as  may  be 
seen  by  reference  to  the  economic  classification  of  fibers  for  paper  given 
on  page  331.  The  make-up  of  paper  varies  with  its  manufacture  in  differ- 
ent countries  and  depends  on  the  cheapness  and  abundance  of  the  fibers 
which  are  most  available  commercially.  In  this  country  the  various  wood- 
pulps  (mechanical,  sulfite,  and  soda  pulps)  are  the  chief  basis  for  paper 
making,  although  many  other  fibers,  such  as  cotton  (from  rags,  cotton 
waste,  and  linters),  linen  (from  rags  and  flax  waste),  hemp  and  jute  (from 
old  fabrics  and  tow  waste),  Manila  hemp  (from  old  cordage  and  tow), 
and  many  other  miscellaneous  vegetable  fibers  are  extensively  used,  some- 
times alone,  but  more 
often  in  admixture  in 
varying  proportions  with 
wood-pulps.  The  fibers 
used  in  other  countries, 
however,  are  much  more 
extensive;  besides  those 
already  enumerated  we 
find  grass  fibers  like  es- 
parto; straw  fibers  such  as 
those  from  corn,  wheat, 
and  rice;  as  well  as  fibers 
from  the  bamboo,  mulberry 
tree,  linden  tree,  and  the 
hop  vine  and  sugar  cane. 

In  the  examination 
of  paper  fibers  it  is  first 
necessary  to  isolate  the 
individual  fibers  from  the 
paper  web  and  the  sizing 

and  loading  materials.  This  may  usually  be  done  by  tearing  up  the 
sample  of  paper  into  small  pieces  and  then  boiling  with  water  and  beating 
up  with  a  vigorous  stirring  (as  with  an  egg  beater)  until  a  fine  pulp  is  pro- 
duced. This  is  washed  and  strained  off  on  a  fine  copper  gauge,  after  which 
the  fibers  may  usually  be  rather  easily  picked  apart  for  examination. 

It  must  be  borne  in  mind  that  the  fibers  in  paper  have  undergone  a 
rather  severe  chemical  and  mechanical  treatment  during  the  processes 
of  manufacture  into  paper,  consequently  they  will  exhibit  characteristics 
rather  different  from  those  of  the  natural  fibers.  These  operations  include, 
as  a  rule,  a  prolonged  boiling  under  high  pressure  with  caustic  alkalies  or 
calcium  bisulfite,  and  also  a  treatment  with  comparatively  strong  solutions 
of  bleaching  powder.     In  paper-making  it  is  also  necessary  to  have  short, 


Fig.  360. — Ground  Wood-pulp  from  Aspen.     (Herzog.) 


852 


MINOR   VEGETABLE   FIBERS   ANE   PAPER  FIBERS 


fine  fibers  rather  than  the  compai-ativcly  long  and  sometimes  much  coarser 
fibers  employed  for  spinning  textiles. 

The  following  is  a  brief  description  of  the  more  important  paper  fibers : 
(1)  Mechanical  Wood  Fiber. — This  is  prepared  by  grinding  up  wood 
so  that  it  becomes  disintegrated  into  the  short  ultimate  fibers.  For  this 
purpose  the  white  soft  woods  (like  poplar)  are  largely  used;  also  many 
coniferffi  woods  (like  pine,  fir  and  spruce)  as  well  as  some  leafed  trees 
(like  the  aspen,  linden  and  willow).  Mechanical  wood  fiber  contains 
practically  all  of  the  natural  elements  present  in  the  wood,  and  conse- 


FiG.  361. — Ground  Wood-pulp  from  Fir.     (Herzog. 


quently  is  very  easy  to  recognise  and  identify  both  by  microscopic  examina- 
tion and  by  microchemical  tests.  According  to  Hohnel,  the  coniferous 
varieties  of  wood  fiber  are  characterised  by  their  tracheides  covered  with 
large  circular  disks.  These  are  mostly  flat,  and  usually  torn  and  fraj'cd 
more  or  less  bj^  the  process  of  grinding,  and  have  blunt  wide  ends,  and 
are  furthermore  relatively  thin  walled. 

The  wood  fiber  from  leaf  trees  lacks  these  characteristic  tracheides, 
but  possesses  instead  numerous  remnants  of  vascular  tissue,  which  are 
short  and  broad.  These  are  covered  quite  thickly  with  small  flattened 
disks  which  mutually  touch  each  other.     There  are  also  present   thin 


PAPER   FIBERS   AND   THEIR  EXAMINATION 


853 


fibers  which  (in  the  so-called  white  woods)  are  generally  only  slightly 
thickened. 

When  it  is  a  question  of  distinguishing  between  the  varieties  of 
coniferae  which  occur  in  a  paper,  then  the  tracheides  no  longer  suffice, 
as  these  are  nearly  the  same 
for  all  such  trees.  On  the 
other  hand,  the  marrow-lined 
cells  which  occur  in  large 
number  in  all  wood-pulps,  in 
the  case  of  the  coniferae  possess 
very  different  characteristics. 
Herewith  is  given  only  the 
most  important  points  which 
may  serve  for  an  examina- 
tion of  the  fibers,  as  well 
as  the  characteristics  shown 
in  Fig.   360.       The 


Fig.  362. — Wood-pulp  from  Fir.     (Herzog.) 
marrow 

cells  appear  in  wood-pulp  usually  as  brick-shaped  cells  connected  in 
a  parallel  manner.  If  all  of  these  cells  are  provided  with  single  round 
pores,  then  it  indicates  pulp  of  spruce  wood.  If  there  occurs  besides 
these  single-pored  marrow  cells  others  which  show  small  breeched  spots, 


tragi  .3^ 


'fej 


Fig.  363. — Wood-pulp  Fibers  from  Willow.     (Herzog.) 

then  we  have  pine  wood-pulp  (Fig.  361).  Finally,  if  a  portion  of  the 
marrow  cells  are  provided  with  large,  and  very  noticeable  teeth  which 
project  far  into  the  lumen  (in  which  occur  small  circular  spots)  while  the 
rest  show  a  series  of  large,  rounded,  quadrangular  perforations  which  take 
up  almost  the  entire  width  of  the  lumen,  then  the  paper  consists  of  fir 
wood  (Fig.  362). 


854 


MINOR  VEGETABLE   FIBERS   AND   PAPER  FIBERS 


With  respect  to  the  examination  of  the  principal  leafed  woods,  only 
the  most  essential  will  be  given.  The  wood-pulp  elements  of  willow 
(Fig.  363),  poplar  (Fig.  364)  and  linden  trees  are  very  thin-walled, 
while  those  of  maple  are  thick-wallcd.  The  woody  material  of  the 
linden  shows  remnants  of  vascular  tissue  and  tracheides,  which  besides 
exhibiting  disks,  also  shows  a  broad  spiral  band.  The  former  are  up 
to  60  microns   wide.     Maple   pulp   also   shows  numerous   remnants   of 


Fig.  364. — Wood-pulp  from  Poplar,     (Herzog.) 


vascular  tissue  which  are  spotted  and  spirally  thickened,  though  gener- 
ally only  one  of  these  marks  is  present.  Willow  and  poplar  have  fibers 
very  much  ahke,  being  associated  with  vascular  tissue  which  is  com- 
pletely covered  with  hexagonal  disk-like  spots. 

Paper  or  paper  pulp  containing  mechanical  wood-pulp  always  shows 
the  woody  fiber  reactions  in  the  most  distinct  manner.  Aniline  sulfate, 
for  example,  gives  an  intense  golden-yellow  color.  Further  it  is  to  be 
remarked  that  only  pasteboard,  but  not  paper,  as  a  rule,  is  made  entirely 
from  mechanical   wood-pulp.      Therefore,   in   the   case   of  papers  which 


PAPER   FIBERS   AND   THEIR  EXAMINATION 


855 


show  the  woody  fiber  reaction,  one  must  also  look  for  other  fibers  after 
the  application  of  the  woody  fiber  reaction. 

(2)  Chemical  Wood  Fiber.— This  includes  three  principal  varieties, 
depending  on  the  method  of  manufacture:  (a)  sulfite  pulp,  made  by 
boiling  chipped  wood  under  high  pressure  (90  to  150  lbs.)  with  calcium 
bisulfite;  (6)  soda  pulp,  made  by  a  similar  boiling  with  caustic  soda 
liquor;  (c)  sulfate  pulp,  made  by  boiling  with  a  mixture  of  caustic  soda 
and  sodium  sulfide.  When  wood  is  decomposed  into  its  elements  by 
chemical  methods  the  product  so  obtained  is  rather  pure  cellulose;    so 


Fig.  365. — Chemical  Wood-pulp  from  Fir.     (Herzog.) 


that  whereas  ground  wood-pulp  shows  the  lignin  reactions  in  a  very 
distinct  manner,  paper  containing  chemical  pulp  does  so  either  not  at 
all  or  only  in  a  slight  degree.  By  the  boiling,  however,  with  chemicals 
not  only  is  the  lignin  destroyed,  but  the  nature  of  the  woody  elements 
is  also  changed,  so  that  chemical  cellulose  cannot  be  recognised  under  the 
microscope  as  easily  as  ground  wood.  Chemical  pulp  is  chiefly  prepared 
from  the  long-fibered  varieties  of  coniferous  trees.  The  fibers  appear 
broad,  ribbon-like,  often  twisted,  and  resemble  cotton  (being  broader), 
however);  thin-walled;  occasionally  there  may  be  seen  large  spots  sur- 
rounded by  a  halo,  although  always  indistinct  (Fig.  365).     The  best  way 


856 


MINOR  VEGETABLE  FIBERS  AND  PAPER  FIBERS 


to  see  them  is  to  treat  the  fiber  with  chlor-iodide  of  zinc,  when  most  of  them 

become  violet,  others  acquire  a  dirty  violet  to  yellow  color,  and  the  marks 

of  the  large  spots  stand  out  distinctly.    The  fibers  are  30  to  60  microns 

wide,  and  show  no 
joints.  They  are  also 
almost  entirely  whole, 
whereas  those  of 
mechanical  pulp  are 
much  broken  and 
torn  apart.  The  ends 
are  generally  broad, 
thin- walled  and  blunt. 
Marrow  elements  are 
only  occasionally  ob- 
served, and  exhibit 
only  indistinct  struc- 
tural proportions. 
From  these  remarks 
it  is  evident  that  me- 
chanical and  chemical 
wood  pulps  may  be  dis- 
tinguished from  each 
other  very  easily. 
(3)  Cotton. — This  fiber  as  found  as  a  constituent  of  paper  exhibits 

about  the  same  characteristic  appearance  as  already  described  under  its 

consideration  as  a  textile  fiber.     The  chief  difference  to  be  noted  is  that 

the  fiber  is  generally 

torn    (Fig.  366)    and 

not    nearly    so    well 

preserved.     It  is  easy 

to    recognise     cotton 

in  paper  by  its  well- 
defined  walls,  its  char- 

acteristic      twist 

(though     care     must 

sometimes     be    exer- 
cised not    to  confuse 

this    with     that     of 

some    wood     fibers) , 

and  its  cuticle.     The 

cell-wall  is  frequently 

broken  down,  but  never  shows  the  knotted  swellings  to  be  noticed  on 

linen  and  hemp. 


Fig.  366. — Cotton  Fibers  from  Paper.     (Litschauer.) 


Fig.  367. — Linen  Fibers  from  Paper.     (Litschauer.) 


PAPER  FIBERS  AND  THEIR  EXAMINATION 


857 


(4)  Linen. — It  would  be  erroneous  to  expect  to  find  linen  fibers  in 
paper  in  the  same  con- 
dition as  that  in  which 
they  occur  in  fabrics.  As 
a  rule  the  linen  fibers 
employed  in  paper  are 
derived  from  flax  tow  and 
rags  almost  without  ex- 
ception. In  old  linen 
rags  the  fibers  are  already 
much  broken  up  and  spilt 
and  more  or  less  de- 
stroyed ;  stiU  more  is  this 
the  case  in  paper,  espe- 
cially in  the  more  deli- 
cate kinds.  The  knotted 
swellings  on  the  linen 
fiber  are  characteristic, 
and  they  occur  around 
the  joints.  Longitudinal 
rents  and  fissures  are  so 
frequent,  that  the  lumen  is  scarcely  recognisable; 


Fig.  368.- 


Hemp  Fiber  from  Paper-pulp,  Much  Decom- 
posed.    (Herzog.) 


Fig.  369. — Paper-pulp;  Mixture  of  Ground  Wood,  Sulfite 
Pulp  and  Cotton.     (Herzog.) 


and  at  the  ends  the 
linen  fibers  in  paper 
are  often  completely 
frayed  out  into  fine 
fibrillffi  (Fig.  367). 

(5)  Hemp  Fiber. — 
These  fibers  occur  in 
most  papers  in  a  well- 
preserved  condition. 
Such  papers  are  made 
from  hemp  tow,  like 
banknote  paper,  etc., 
and  have  great  endur- 
ance and  strength  even 
in  thin  tissues.  Paper 
prepared  from  old 
hemp  rags  show 
broken-up  fibers  in  the 
same  manner  as  linen 
paper.  Since  hemp 
fibers,  however,  are 
more  brittle,  the  torn 


858 


MINOR  VEGETABLE   FIBERS  AND   PAPER   FIBERS 


ends  appear  somewhat  shorter  than  with  Hnen.  There  are  also  always 
a  smaller  number  of  destroyed  fibers,  which  is  of  use  in  determining  hemp 
fibers  in  paper  with  certainty  (Fig.  368). 

(6)  Straw  Fibers. — These  are  obtained  from  wheat,  rye,  oats,  rice,  and 
corn,  and  are  always  easy  to  recognise  in  paper,  since  besides  the  usual 
characteristics  of  fibers  there  occur  in  them  elements  which  are  especially 
easy  to  recognise.  These  are  bundles  of  thin  spiral  and  reticulated  vascular 
tissue  or  fragments  of  such  (portions  of  spiral-shaped  ridges,  single  rings, 
etc.).  Furthermore  there  are  present  large,  loose  parenchymous  cells, 
generally  wide,  thin-walled,  short,  with  blunt  angles,  or  long;  in  the  last 
case  up  to  33  microns  broad  and  often  porous.  Thirdly,  there  are  very 
thick,  silicified  epidermal  cells.  These  possess  highly  characteristic  forms 
and  serve  for  the  recognition  of  straw  in  paper  with  great  certainty.     They 

are  flat,  possess  thick- 
ened outer  walls  and 
thin  inner  walls.  The 
side  walls  exhibit  numer- 
ous regular  curves  or 
undulations,  so  that  the 
long,  narrow  epidermal 
cells  appear  like  double- 
edged  saws  (Figs.  370, 
371).  The  fibers  of  the 
first  four  varieties  of 
straw  named  are  inci- 
dentally as  broad  as 
linen  fibers,  but  also 
shorter.  They  are  not 
lignified  and  are  rela- 
tively thinner-walled  than  linen  fibers.  The  ends  are  almost  always 
pointed  or  forked.  The  numerous  joints  are  also  remarkable;  these, 
however,  were  not  present  originally,  but  are  a  result  of  the  preparation 
of  the  straw.  Furthermore,  straw  fibers  are  very  unequal  in  thickness; 
next  to  very  thin  ones  may  be  found  very  thick  and  short  ones.  An 
important  difference  between  straw  and  linen  fibers  lies  in  their  condition 
of  preservation.  Straw  fibers  in  paper  are  always  well  known  for  having 
all  their  peculiarities — namely,  their  pointed  and  frequently  forked  ends 
which  are  often  to  be  seen,  whereas  linen  fibers  occur  almost  altogether 
in  the  form  of  fragments,  which  even  then  are  usually  more  or  less  decom- 
posed. According  to  Wiesner  the  mean  diameters  of  straw  fibers  are  as 
follows:  barley,  5  to  12  microns;  oats,  10  to  21  microns;  rye,  9  to  17 
microns;  wheat,  10  to  21  microns;  fibers  of  corn  can  be  distinguished  from 
the  usual  straw  fibers  by  their  large  diameters  (10  to  82  microns)  and  by 


Fig.   370. 


-General   Appearance   of    Straw    Fibers   from 
Paper.     (Hohnel.) 


PAPER  FIBERS  AND  THEIR  EXAMINATION 


859 


their  form.  They  usually  have  blunt,  forked,  knotty  ends,  which  often 
appear  almost  like  antlers.  Their  length  amounts  to  0.4  to  5.6  mm.,  and 
is  almost  distinguishing.  The  fibers,  as  a  rule,  are  relatively  thin-walled, 
and  the  lumen  appears  only  very  seldom  as  a  narrow  line.  They  contain, 
according  to  Wiesner,  a  steel-gray  tannin  matter,  and  unlike  fibers  of 
oats,  barley,  rice,  wheat,  and  rye,  are  hgnified.  Corn  paper  (Fig.  371) 
can  consequently  be  distinguished  from  ordinary  straw  paper  and  from 
true  rice  paper  by  the  fibers.  The  various  straw  papers,  however,  can 
only  be  distinguished  from  each  other  with  certainty  by  the  aid  of  the 
epidermal  cells,  and  even  by  the  form  as  well  as  by  the  dimensions  of  these 
cells.  According  to  Wiesner,  these  epidermal  cells  have  the  following 
dimensions : 


Corn  straw .  .  . 
Rye  straw .  .  .  . 
Esparto  straw 
Barley  straw . . 
Wheat  straw . . 
Oat  straw .  .  .  . 


Length  in  Microns. 

Breadth  in  Microns. 

108-252 

36-90 

86-345 

16-10 

28-  88 

7-19 

103-224 

12-14 

152-449 

18-24 

186-448 

12-17 

As  to  differences  in  form,  it  may  be  said  that  oat,  rye,  and  wheat  straw 
have  right-angled  epidermal  cells.  The  side  walls,  in  the  case  of  rye 
straw,  are  very  wavj*,  with  wheat  straw  almost  straight,  and  with  oat 
straw  slightly  wavy.  The  epidermal  cells  of  barley  straw  appear  more 
irregular  and  almost  rhombohedral  in  form.  In  paper  from  corn  straw 
there  occur  epidermal  cells  which  are  very  irregular  and  broad  and  rough- 
walled;  they  often  occur  in  large  groups,  which  are  as  much  as  1  sq.  mm. 
in  size.  Rice  straw  (Fig.  372)  possesses  very  narrow  fibers  (mostly  7 
microns  broad)  and  narrow,  relatively  long  epidermal  cells,  with  remark- 
ably thick  external  walls,  which  exliibit  wart-like  swellings.  The  Chinese 
rice  papers  (mostly  wall-papers)  are  usually  sized  with  a  thick  paste,  and 
also  contain  many  parenchym  cells,  which  give  additional  strength 
(Hohnel). 

(7)  Jute  Fiber. — The  characteristics  of  this  fiber  in  paper  are  prac- 
tically the  same  as  those  already  given  under  its  consideration  as  a  textile 
fiber. 

(8)  Esparto  Fiber. — This  fiber  is  obtained  from  a  grass,  stiya  tenacis- 
sima,  and  is  extensively  used  for  paper-making  in  Europe.  In  its  micro- 
scopic characteristics  it  belongs  to  the  general  category  of  straw  fibers. 
Hohnel  states  that  it  is  distinguished  by  its  peculiar  epidermal  cells 
(Fig.  373). 


860 


MINOR   VEGETABLE   FIBERS  AND   PAPER   FIBERS 


(9)  Bamboo  Fiber. 


Fig.  371. 


-Straw  Paper-pulp  Showing  Siliceous  Cells 
(Herzog.) 


This  is  worked  up  into  paper  in  China,  Japan, 
Jamaica,  England,  and 
other  countries.  The  fine 
paper  known  by  the  name 
of  Chinese  silk  paper  is 
usually  made  from  bam- 
boo, partly  from  old  bam- 
boo cane,  and  partly  from 
the  young  shoots.  Ac- 
cording to  Wiesner,  bam- 
boo paper  exhibits  bast 
fibers  differing  much  in 
form  but  which  can  be 
included  in  the  following 
three  forms:  (1)  Short 
(mean  length,  720  mi- 
crons), narrow  fibers,  hav- 
ing a  line-shaped  lumen. 
(2)  Long,  wide,  somewhat 
thickened  to  17  microns 
in  diameter.  (3)  Long, 
ribbon-shaped  flat  fibers,  of  very  changing  breadth,  which  are  twisted 
somewhat  after  the  man- 
ner of  cotton.  Of  course 
there  will  also  be  found  in 
bamboo  paper  occasional 
masses  of  vascular  tissue 
(mesh,  porous,  as  well  as 
ring  and  spiral  forms). 
Often  single  rings  can  be 
observed  in  the  paper. 

(10)  Paper  Mulberry 
Fiber.— The  soft  bast  filler 
of  the  paper  mulberry  tree 
is  extensively  employed  in 
Japan  and  China  for  the 
making  of  a  quality  of 
paper  especially  charac- 
teristic of  these  countries. 
This  fiber  may  be  distin- 
guished by  the  thin,  curly, 
white  coat  of  cellulose  with  which  it  is  surrounded ;  also  the  short,  bar- 
like or  prismatic  crystals,  which  occasionally  adhere  to  the  fibers  in  the 


Fig.  372. — Chinese  Rice  Straw  Paper. 


PAPER  FIBERS  AND  THEIR   EXAMINATION 


861 


Fibers  of  Esparto 
Grass,  s,  Short  scleren- 
chymous elements;  Z,  cells; 
/,  fibers;  h,  hairs;  e,  epi- 
dermal cells.     (Hohnel.) 


paper  (Fig.  374),  The  fiber  of  the  paper  mulberry  tree  is  the  longest 
employed  in  paper-making.  Hence  the  tenacit}^  of  the  Japanese  and 
Chinese  papers  prepared  from  this  material. 
Hence  also  the  possibility  of  preparing  from  this 
fiber  a  paper  which  is  mesh-like,  transparent  and 
soft  on  the  surface. 

(11)  Hop  Fiber. — This  is  principally  used  in 
fine  papers.  In  such,  however,  the  single  fibers 
are  so  much  decomposed,  that  they  are  deter- 
mined only  with  difficulty. 

(12)  Papers  with  Cellular  Structure.— The 
so-called  Chinese  rice  paper  and  the  papyrus 
of  the  ancients,  are  papers  which  differ  completely 
in  their  microscopical  properties  from  those 
hitherto  considered.  They  consist  principally  Fig.  373. 
of  thin-walled,  free  parenchymous  cells,  and  are 
obtained  by  cutting  out  with  a  knife  the  pith  of 
certain  monocotyledonous  soft  stems. 

(A)    Chinese  paper  (so-called  rice  paper)  is 

prepared  in  a  simple  manner  by  cutting  out  in   a   spiral  form  the  pith  of 

Aralia  papyrifera  (Fig.  375).     The  sheets  so  obtained  are  then  pressed 

and  attain  a  size  of  about 
11  sq.  dcm.  Each  sheet 
consists  only  of  a  single 
piece  of  250  to  300  mi- 
crons in  thickness.  Only 
smaller  and  more  imper- 
fect kinds  appear  in 
joined  strips  1  to  2  cm. 
wide.  These  are  cut  out 
of  the  pith  in  radial  di- 
rections. The  microscope 
shows  polyhedral  paren- 
chymous cells,  which  are 
completely  filled  with  air 
that  can  easily  be  dis- 
placed with  alcohol. 
The  cells  are  striated 
lengthwise,  and  measure 
135  to  180  microns  in 
length    and    54    to    92 

microns  in  breadth.     The  cells  are  provided  with  small  pores,  and  many 

contain  crystal  husks  of  calcium  oxalate. 


Fig.  374. — Fiber  from  Paper  Mulberry.     (Herzog.) 


862 


MINOR   VEGETABLE  FIBERS  AND   PAPER   FIBERS 


Fig.  375. — Cliinesc  Rice  Paper. 


(B)  Papyrus  of  the  ancients  was  cut  from  the  fabric  of  the  stalk  of 

the  Cyperus  papyrus  (Fig. 
376).  This  fabric  con- 
sists of  a  curly,  almost 
snow-white  parenchym 
similar  to  elder  pith,  in 
which  numerous  vascular 
Inmdles  are  imbedded. 
The  papyrus  rolls  are  so 
prepared  that  the  pith 
is  cut  up  in  very  thin 
sheets,  and  these  are 
generally  glued  together 
in  three  layers  not  paral- 
lel, but  crossing  one 
another.  Hence  the  old 
papyrse  show  t,wo  systems 
of  striations  at  right 
angles  to  each  other; 
which  are  caused  by  the 
vascular  bundles  (Hohn- 

el).     The  sheets  of  pith  are  about  80  microns  in  thickness  according  to 

Wiesner.       The     paren- 

chymous   cells   are  large 

and      thin-walled,     and 

nearly    always     contain 

small  crystals  of  calcium 

oxalate.      The    vascular 

l)undles    are    well     pre- 
served even   in   antique 

samples,    and    allow    of 

their    histological   struc- 
ture   to     be    recognised 

very  distinctly  mider  the 

microscope. 

With   regard    to   the 

chemical   reactions   that 

can  be  used  in  the  large- 

scale     examination    of 

paper     for     its     fibers, 

only     those     pertaining 

to  woody  fiber  are  use- 
ful (aniline  sulfate,  phloroglucinol  and  hydrochloric  acid,   or  indol    and 


Fig.  376. — Ancient  Papyrus. 


PAPER  FIBERS  AND  THEIR  EXAMINATION  863 

hydrochloric  acid).  By  these  reactions,  however,  a  definite  fiber  is 
seldom  distinguished;  but  only  the  presence  of  more  or  less  lignified 
matter  is  recognised.  Hence,  by  the  use  of  the  woody  fiber  reactions 
the  presence  of  hgnified  fibers  in  the  mass  of  the  paper  only  is  indicated; 
the  quantity  present  and  the  kind  of  lignified  fiber  is  not  shown.  We 
must  also  bear  in  mind  with  regard  to  the  species  of  fiber,  that  these  may 
often  be  lignified  or  not  according  to  the  method  of  their  preparation, 
as  by  certain  chemical  means  (alkalies,  acids,  bleaching  materials)  the 
woody  fiber  can  be  destroyed.  When  two  or  more  fibers  are  mixed 
together,  the  determination  of  the  relative  amounts  of  each  present  can 
only  be  effected  by  the  use  of  the  microscope,  and  indeed  only  by  an 
accurate  counting  of  the  different  kinds  of  fibers  found. 


CHAPTER  XXV 
GENERAL  ANALYSIS  OF  THE  TEXTILE  FIBERS 

1.  General  Classification. — In  a  commercial  examination  of  most 
manufactured  yarns,  fabrics,  etc.,  it  will  only  be  necessary  to  distinguish 
between  wool,  silk,  cotton,  linen,  jute,  hemp,  and  ramie.  Under  wool 
must  also  be  included  analogous  animal  hairs,  such  as  mohair,  cashmere, 
etc.  Other  animal  fibers,  such  as  cow-hair  and  horse-hair,  may  easily 
be  distinguished  even  by  the  naked  eye.  Of  course  there  are  numerous 
other  fibers  of  vegetable  origin  which  are  employed  more  or  less  for 
textile  materials,  but  either  they  are  not  liable  to  occur  in  conjunction 
with  the  above  fibers,  or  they  may  be  readily  distinguished  from  the  latter 
without  requiring  a  special  examination. 

Dodge  gives  a  list  of  American  commercial  vegetable  fibers,  the  total 
number  of  which  is  about  30,  of  which  the  more  important  are  as  follows: 

Six  bast  fibers: 

Flax,  Linum  usitatissimum. 

China  grass,  Boehmeria  nivea  and  B.  tcnacissima. 

Hemp,  Cannabis  sativa. 

Jute,  Corchorus  capsularis  and  C.  ulitorius. 

Sunn  hemp,  Crotalaria  juncea. 

Cuba  bast.  Hibiscus  tiliaceus. 
The  first  five  of  this  class  are  used  for  spinning  fibers,  while  the  latter  finds  use 
for  milUnery  purposes. 
Two  surface  fibers: 

Cotton,  Gossyjnum.  sp. 

Raphia,  Raphia  ruffia. 
Fifteen  structural  fibers,  representing  agaves,  palms,  and  grasses: 

Sisal  hemp,  Agave  rifjida 


Cordage  fibers. 


Manila  hemp,  Musa  textilis 
Mauritius  hemp,  Fourcroya  giganlea 
New  Zealand  flax,  Phormium  tenax 
Tampico  or  Istle,  Agave  heieracantha 
Bahia  piassave,  Attalea  funifera 
Para  piassave,  Leopoldinia  piassaba 
Mexican  whisk  or  Broom  root,  Epicampes  macroura 
Cabbage  palmetto,  Sabal  palmetto 
Crin  vegetal,  Chamwi'ops  humilis 
Spanish  moss,  Tillandsia  usneoides 
Saw  palmetto,  Serenoa  semdata 
Cocoanut  fiber,  Cocas  nvcifera 
Esparto  grass,  Stipa  tenacissima,  a  paper  fiber. 
Vegetable  sponge,  Luffa  cegyptica,  a  substitute  for  sponge. 

864 


Brush  fibers. 


Upholstery  and  matting  fibers. 


MICROSCOPICAL  INVESTIGATION  865 

The  native  vegetable  fibers  of  the  United  States  that  are  produced 
in  commercial  quantities  are  cotton,  hemp,  flax,  palmetto  fiber,  and  vege- 
table hair  from  Spanish  moss. 

2.  Microscopical  Investigation. — The  best  method  of  distinguishing 
quaUtatively  between  the  various  fibers  above  mentioned  is  by  the  use 
of  the  microscope,  whereby  their  characteristic  physical  appearance  may 
be  readily  observed.  Each  of  the  fibers  in  question  presents  certain 
microscopical  peculiarities,  so  that  no  difficulty  is  encountered  in  dis- 
tinguishing between  them.  The  difference  in  the  microscopical  appear- 
ance of  these  fibers  may  be  comparatively  observed  by  reference  to  the 
figures  given  in  the  preceding  pages. 

In  advising  as  to  the  methodical  examination  of  fibers,  Hohnel  states 
that  a  commercial  fiber  should  first  be  described  as  completely  as  possible 
by  the  field  of  its  use  if  it  is  desired  to  know  all  of  its  distinguishing  marks. 
In  such  a  case  it  is  possible  to  arrive  at  a  position  where  an  analytical 
table  may  be  prepared  capable  of  being  used  for  the  determination  of  the 
fiber  as  well  as  of  the  plant.  Hohnel  deviates  in  this  connection  from  the 
not  unusual  point  of  view  that  to  be  able  to  fix  accurately  the  identity 
of  a  fiber  it  is  only  necessary  to  furnish  a  complete  description  of  its 
physiography.  He  is  opposed  to  the  opinion  that  a  mere  description  is 
all  that  is  necessary,  because  by  this  means  it  is  not  always  possible  to 
differentiate  between  such  a  fiber  and  the  one  immediately  next  to  it  in 
properties.  In  fact,  up  to  now  it  has  been  customary  to  regard  practical 
microscopy  more  as  a  descriptive  science  than  as  a  comparative  one,  and 
thus  to  attribute  to  the  easily  recognisable  characteristics  too  great  an 
analytical  accuracy.  The  recognition  of  fibers  lies  much  deeper,  and  must 
be  established  by  a  labor  implying  deep  insight  and  often  much  toil,  and 
must  often  be  sought  for  in  quite  unessential  peculiarities  of  very  sHght 
anatomical  importance. 

The  principal  characteristics  should  always  be  morphological,  that 
is  to  say,  those  which  define  the  form  of  the  fiber  (base,  lumen,  relative 
thickness  of  cell-walls,  points,  condensed  forms,  etc.).  The  other  char- 
acteristics, namely,  the  comparative  size  and  the  chemical  properties 
of  the  fiber,  should  only  be  considered  of  secondary  importance.  The 
size  of  the  fibers  often  varies  in  an  unexpected  manner,  especially  in 
plant  fibers  where  the  difference  is  a  physiological  one.  The  longer, 
for  instance,  a  sample  of  linen,  jute,  etc.,  may  be  in  consequence  of  favor- 
able external  conditions,  the  longer  wiU  also  be  the  fibers  contained  in 
the  same. 

As  far  as  the  microchemical  relations  are  concerned,  heed  must  be 
taken  of  the  fact  that  in  the  literature  of  the  subject  attention  is  seldom 
paid  to  the  concentration  of  the  reagents  employed,  and  further  it  must 
he  borne  in  mind  that  in  dealing  with  fabrics  containing  artificially  dyed 


866  GENERAL   ANALYSIS   OF   THE   TEXTILE   FIBERS 

fibers,  chemical  color  reactions  in  general  cannot  be  applied.  Iodine  and 
sulfuric  acid,  for  instance,  depending  on  the  concentration,  give  with 
cotton  all  colors  from  a  bii^ht  rose  to  a  dark  blue,  with  hemp  from  yellow 
to  greenish  blue,  etc.  Again,  fibers  may  be  so  changed  by  bleaching 
that  the  microchemical  reactions  as  described  do  not  hold  true.  Woody 
matter  can  be  completely  dissolved  out  by  the  bleaching  process,  and  the 
cuticule  be  destroyed.  The  behavior  of  cotton  towards  copper  ammo- 
nium oxide  solution  will  not  hold  for  well-bleached  cotton  yarn,  because 
in  such  the  cuticule  is  almost  entirely  lacking.  The  statements  con- 
cerning the  chief  chemical  distinctions  between  linen,  hemp,  and  jute 
fibers  are.  useless  when  one  is  dealing  with  well-bleached  or  dyed  materials. 
Consequently,  in  the  testing  and  investigation  of  fibers  the  morpho- 
logical properties  should  be  given  precedence,  as  only  these  exhibit  well- 
defined  characteristics.  In  order  to  be  thoroughly  certain  when  testing 
by  microchemical  properties,  it  is  necessary  always  to  employ  the  same 
reagents.  Every  characteristic  of  a  fiber  has  only  a  relative  value, 
because  it  is  only  serviceable  in  distinguishing  the  fiber  in  question  from 
one  or  more  particular  fibers,  while  with  others  it  would  be  worthless. 
Thus  it  is  easy  to  distinguish  between  jute  and  hemp  by  the  so-called 
*'  knots  "  or  folds  of  flexion,  but  this  characteristic  will  not  enable  one  to 
distinguish  between  hemp  and  flax. 

3.  Qualitative  Chemical  and  Microchemical  Tests. — A  rough  physical 
test  to  distinguish  between  animal  and  vegetable  fibers  is  to  burn  them 
in  a  flame.  Vegetable  fibers  burn  very  readily  and  without  producing 
any  disagreeable  odor;  animal  fibers,  on  the  other  hand,  burn  with  some 
difficulty  and  emit  a  disagreeable  empyreumatic  odor  resembling  that  of 
burning  feathers.  The  burnt  end  of  the  fiber  is  also  characteristic,  vege- 
table fibers  burning  off  sharply  at  the  end,  whereas  animal  fibers  fuse 
to  a  rounded,  bead-like  end. 

Tables  I  and  II  exhibit  the  characteristic  chemical  reactions  of  the 
principal  fibers,  and  by  suitably  employing  these  tests  the  principal  fibers 
may  be  easily  distinguished  from  one  another. 

4.  Reagents  for  Testing  Fibers. — The  reagents  employed  for  the  tests 
in  the  tables  may  be  prepared  as  follows: 

(1)  Madder  Tincture. — Extract  1  gram  of  ground  madder  with  50  cc.  of  alcohol, 
and  filter  from  undissolved  matter.  Used  for  distinguishing  between  cotton  (bright 
yeUow)  and  linen  (orange.) 

(2)  Cochineal  Tincture. — This  is  made  in  the  same  manner  as  the  above,  using 
1  gram  of  ground  cochineal  insects.  Used  for  distinguishing  between  cotton  (red)  and 
linen  (violet). 

(3)  Fuchsine  Solution. — Also  known  as  Liebermann's  test  solution.  Dissolve  1  gram 
of  Fuchsine  (Magenta)  in  100  cc.  of  water,  then  add  caustic  soda  solution,  drop  by 
drop  until  the  fuchsine  solution  is  decolorised;  filter  and  preserve  in  a  well-stoppered 
bottle.     In  applymg  the  test  with  this  reagent,  the  mixed  fibers  are  treated  with  the 


REAGENTS   FOR  TESTING   FIBERS 


867 


hot  solution,  then  well  rinsed,  when  the  animal  fibers  will  be  dyed  red,  the  vegetable 
fibers  remaining  colorless. 

(4)  Zi7ic  Chloride  Solution. — Dissolve  1000  grams  of  zinc  chloride  in  850  cc.  of 
water,  and  add  40  grams  of  zinc  oxide,  heating  untU  complete  solution  is  effected. 

(5)  Stannic  Cfiloride  Solution. — This  may  be  prepared  bj^  dissolving  15  grams  of 
stannous  chloride  (SnCh)  in  15  cc.  of  concentrated  hydrochloric  acid,  and  then 
gradually  adding  3  grams  of  powdered  potassium  chlorate  (KCIO3).  Dilute  to  100  cc. 
with  water. 

(6)  Silver  Nitrate  Solution. — 5  grams  of  silver  nitrate  (AgNOs)  are  dissolved  in 
100  cc.  of  water,  and  preserved  in  an  amber-colored  bottle. 

(7)  Mercury  Nitrate,  Milton's  Reagent. — Dissolve  10  grams  of  mercury  in  25  cc.  of 
nitric  acid  diluted  with  25  cc.  of  water  at  a  lukewarm  temperature.  Mix  this  solution 
with  one  of  10  grams  of  mercury  in  20  cc.  of  fuming  nitric  acid.  Used  for  testing 
presence  of  animal  fibers  (red) ,    Solution  is  not  very  stable. 

TABLE  I 


Test. 

Wool. 

Silk. 

Linen. 

Cotton. 

Dyestuff  Tests 
Madder  tincture 

Nil 

Scarlet 

Red 

Dyed 

NU 

Partly  diss. 

NU 

Violet  to  brown 

Red  to  brown 

Black 

Black  ppt. 

SweUs  only 

LTndissolved 

NU 

Scarlet 

Red 

Dyed 

NU 

Dissolves 

NU 

NU 

NU 

NU 
No.  ppt. 

NU 
Dissolves 

Orange 
Violet 

NU 

NU 
Dyed 

YeUow 

Cochineal  tincture 

Light  red 

NU 

NU 

Dyed 

Fuchsine 

Acid  dyes  in  general 

Mikado  yeUow 

Action  of  Various  Salts 
Zinc  chloride 

Fiber  undiss.,  yeUow  color 

Stamiic  clUoride 

SUver  nitrate 

Black  color 
Nil 

Mercury  nitrate  (MUlon's) . . . 

Cupric  or  ferric  sulfate 

Sodium  plumbite 

Nil 

NU 

NU 

Ammoniacal  copper  oxide. . .  . 
Ammoniacal  nickel  oxide .... 

SweUs  and  partly  dissolves 
Undissolved 

(8)  Copper  Sulfate  or  Ferric  Sulfate. — Dissolve  5  grams  of  these  salts  respectively 
in  100  cc.  of  water. 

(9)  Sodium  Plumbite. — Dissolve  5  grams  of  caustic  soda  in  100  cc.  of  water  and 
add  5  grams  of  litharge  (PbO),  and  boU  untU  dissolved.  Used  to  detect  the  presence 
of  wool  or  hair  fibers. 

(10)  Ammoniacal  Copper  Oxide,  Schweitzer's  Reagent. — Dissolve  5  grams  of  copper 
sulfate  in  100  cc.  of  boihng  water,  add  caustic  soda  solution  tUl  the  copper  compound 
is  completely  precipitated,  wash  the  precipitate  of  copper  hydrate  well,  then  dissolve 
in  the  least  quantity  of  ammonia  water.  This  gives  a  deep  blue  solution.  All 
solutions  of  ammoniacal  copper  oxide  do  not  cause  cotton  to  swell  up  very  much 
and  dissolve.  The  solution  must  be  concentrated  and  be  freshly  prepared.  The 
best  working  reagent  is  prepared  by  washing  freshly  precipitated  copper  hydrate, 
then  pressing  between  filter  paper  to  remove  excess  of  liauid,  and  dissolving  in  the 


868 


GENERAL   ANALYSIS   OF   THE   TEXTILE   FIBERS 


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REAGENTS   FOR   TESTING  FIBERS  869 

least  possible  amount  of  concentrated  ammonia.  This  reagent  should  be  preserved 
in  a  tightly  stoppered  bottle  and  away  from  the  light.  The  bast  fibers  of  flax  and 
hemp  are  not  completely  soluble  in  this  reagent.  They  are  merely  swollen  strongly, 
and  then  often  present  forms  which  closely  resemble  those  assumed  by  cotton.  If 
the  ammoniacal  copper  oxide  solution  is  not  sufficiently  concentrated  the  globular 
swellings  do  not  occur,  and  the  fiber  only  swells  up  uniformly. 

Bottcher  recommends  that  the  solution  be  prepared  as  follows:  A  glass  tube  about 

2  ins.  in  diameter  and  24  ins.  in  length  is  loosely  filled  with  thin  sheet  copper  and 
and  then  filled  up  with  ammonia  water.  After  a  few  minutes,  the  hquid  is  drawn 
off,  and  then  poured  over  the  copper  again.  Tliis  process  is  repeated  during  several 
hours,  when  a  deep  blue  saturated  solution  of  ammoniacal  copper  oxide  is  obtained. 
Neubauer  recommends  to  precipitate  a  solution  of  copper  sulfate  with  caustic  soda 
in  the  presence  of  ammonium  chloride;  the  precipitate  so  obtained  is  washed  several 
times  by  decantation  and  finally  on  a  filter.  It  is  then  dissolved  in  the  least  quantity 
of  ammonia  water.  Wiesner  prepares  the  solution  by  digesting  copper  turnings  with 
ammonia  water  in  an  open  flask. 

(11)  Ammoniacal  Nickel  Oxide. — Dissolve  5  grams  of  nickel  sulfate  in  100  cc.  of 
water  and  add  a  solution  of  caustic  soda  until  the  nickel  hydrate  is  completely  pre- 
cipitated; wash  the  precipitate  well  and  dissolve  in  25  cc.  of  concentrated  ammonia 
and  25  cc.  of  water.  This  solution  dissolves  silk  almost  immediately,  but  reduces 
the  weight  of  vegetable  fibers  only  about  ^  percent,  and  of  wool  only  |  percent. 

(12)  Caustic  Potash  or  Caustic  Soda. — Dissolve  10  grams  of  the  caustic  alkali  in 
100  cc.  of  water. 

(13)  Sodium  Nitroprusside. — Dissolve  2  grams  of  the  salt  in  100  cc.  of  water. 

(14)  Lead  Acetate. — Dissolve  5  grams  of  lead  acetate  crystals  (sugar  of  lead)  in 
100  cc.  of  water. 

(15)  Sidfuric  and  Nitric  Acids. — The  commercial  concentrated  acids  are  em- 
ployed. 

(16)  Chlorine  Water. — Water  is  saturated  with  chlorine  gas  obtained  by  acting  on 
pyrolusite  (MnOo)  with  hydrochloric  acid.  The  solution  should  be  preserved  in 
amber-colored  bottles. 

(17)  Iodine  Solution. — Dissolve  3  grams  of  potassium  iodide  in  60  cc.  of  water,  and 
add  1  gram  of  iodine.  Dilute  this  solution,  before  using,  with  10  parts  of  water. 
When  the  reaction  is  employed  in  connection  with  sulfuric  acid,  the  latter  consists  of 

3  parts  of  concentrated  sulfuric  acid,  1  part  of  water,  and  3  parts  of  glycerol.  The 
glycerol  has  the  effect  of  preventing  injury  to  the  fibers,  and  at  the  same  time  brings 
out  certain  details  of  the  structure  when  the  fibers  have  previously  absorbed  the 
iodine.  The  fibers  are  moistened  first  with  the  iodine  solution  and  then  with  the 
sulfuric  acid  solution.  According  to  Hohnel,  the  iodine  solution  is  prepared  as  follows: 
One  gram  of  potassium  iodide  is  dissolved  in  100  cc.  of  distilled  water,  and  then  iodine 
is  added  until  the  solution  is  saturated.  In  order  to  maintain  this  solution  in  a  con- 
stantly saturated  state,  an  excess  of  iodine  is  added,  which  remains  at  the  bottom 
of  the  bottle.  The  sulfuric  acid  solution  consists  of  2  parts  by  volume  of  pure  glycerol, 
1  part  by  volume  of  distilled  water,  and  3  parts  of  ordinary  concentrated  sulfuric  acid. 
These  must  be  mixed  gradually  and  carefully,  keeping  the  flask  well  cooled.  Both  of 
these  solutions  in  time  change  their  constitution  and  concentration.  The  iodine 
solution  must  be  renewed,  while  the  sulfuric  acid  solution  may  be  made  good  after 
long  standing  by  the  addition  of  some  concentrated  acid.  The  working  qualities  of 
both  these  solutions  may  be  tested  by  allowing  them  to  act  on  some  raw  flax  fibers. 
These  should  not  swell  up  on  treatment  with  the  sulfuric  acid  (hence  exhibit  no  change 
in  form)  and  should  appear  pure  blue.  If  the  fibers  swell  up,  the  sulfuric  acid  is  too 
concentrated;   if  the  blue  color  is  not  immediately  developed  (only  appears  of  a  violet 


870  GENERAL   ANALYSIS   OF   THE   TEXTILE   FIBERS 

or  rose  color),  the  sulfuric  acid  is  too  dilute.     In  the  first  case  more  glycerol  must  be 
added,  and  in  the  latter  more  concentrated  acid  must  be  added. 

The  reliability  of  tliis  latter  test  depends  very  largely  on  the  method  of  manipula- 
tion. The  most  important  detail  is  probably  the  concentration  of  the  acid  used. 
After  the  fibers  have  been  moistened  with  the  iodine  solution  excess  of  the  latter  should 
be  removed  by  pressing  between  blottmg  paper,  so  that  only  that  portion  of  the 
solution  absorbed  by  the  fibers  remains.  This  is  important,  for  if  the  iodine  solution 
remains  between  the  fibers  the  test  will  be  indecisive.  It  is  also  important  that  the 
individual  fibers  be  separated  from  each  other  so  that  the  reagents  may  act  uniformly. 
If  the  acid  is  too  concentrated  most  of  the  fibers  assume  a  blue  color,  swell  up  and 
finally  dissolve;  whereas  if  the  acid  is  too  weak,  all  the  fibers  exhibit  a  reddish  color- 
ation. In  carrying  out  the  test,  the  fibers  should  first  be  boiled  with  potash,  washed, 
spread  out  on  glass  slides,  dried,  then  treated  with  the  ruby  red  solution  of  iodine, 
again  dried,  and  finally  mounted  in  the  sulfuric  acid  solution. 

(18)  Picric  Add  Solution. — Dissolve  0.5  gram  of  picric  acid  in  100  cc.  of  water. 

(19)  Chlor-iodide  of  Zinc. — Dissolve  1  gram  of  iodine  and  5  grams  of  potassium 
iodide  in  14  cc.  of  water,  then  add  30  grams  of  a  concentrated  solution  of  zinc  chloride 
(Hohnel) .  This  reagent  is  important  for  brmging  out  the  structural  parts  of  vegetable 
fibers. 

(20)  Alcohol. — The  usual  95  percent  commercial  quality;  employed  as  a  useful 
reagent  for  removing  fatty  matters  from  the  fibers  and  also  for  preparing  solutions 
of  various  colored  stains. 

(21)  Ammonia. — Strong  water  of  ammonia;  useful  for  removing  coloring  matters 
from  dyed  fibers  previous  to  examination. 

(22)  Aniline  Sidfate. — The  concentrated  aqueous  solution  slightly  acidulated  with 
sulfuric  acid.     A  good  reagent  for  detecting  lignified  tissue  (yellow  color). 

(23)  Benzoazurine. — Used  in  a  hot  solution  made  slightly  alkaline  with  soda  ash: 
gives  a  violet  color  on  hemp  and  flax  and  both  fibers  show  strong  dichroic  colors. 

(24)  Benzopur-purine  lOB  in  combination  with  Malachite  Green.  This  is  Behren's 
reagent  to  distinguish  between  flax  and  hemp. 

(25)  Carbolic-F uchsijie . — This  is  known  as  Muller's  reagent  for  staining  lignified 
cell  tissues.  Dissolve  1  gram  of  Fuchsine  in  10  cc.  of  alcohol  and  then  add  to  100  cc. 
of  water  in  which  5  grams  of  crystalhsed  carbolic  acid  have  been  previously  dissolved. 

(26)  Chloral  Hydrate. — Useful  for  bringing  out  the  structure  of  vegetable  fibers, 
though  seldom  used;  dissolve  5  grams  of  chloral  hydrate  in  2  cc.  of  water. 

(27)  Chromic  Acid. — Used  for  isolating  the  elements  of  vegetable  fibers.  The 
solution  is  prepared  according  to  Wiesner  by  mixmg  potassium  bichromate  with  an 
excess  of  sulfuric  acid.  From  the  resulting  solution  the  chromic  acid  separates  out 
and  is  then  dissolved  in  an  equal  quantity  of  water.  It  may  be  used  in  the  cold  solution 
and  destroys  the  cellulose  less  than  Schulze's  macerating  solution. 

(28)  Chrysophenine  in  Combination  with  Safranine. — Used  by  Behrens  to  distm- 
guish  between  flax  and  cotton. 

(29)  Dimethyl-par aphenylene-diamine. — This  is  employed  by  Wurster  for  the 
detection  of  lignin  (carmine  color).  It  is  conveniently  used  as  the  sulfate,  a  small 
granule  being  dissolved  in  a  few  drops  of  water. 

(30)  Diphenylamine. — Its  solution  in  concentrated  sulfuric  acid  is  employed  as  a 
test  for  collodion  silk  (blue  color).  The  other  cellulose  silks,  gelatine  silk  and  natural 
silks  remain  unchanged. 

(31)  Chim  Solution. — Used  for  imbedding  purposes  in  making  cross-sections  of 
fibers.  According  to  Meyer  it  is  prepared  by  dissolving  16  grams  of  the  best  gum 
Arabic  in  32  cc.  of  water;  filter  through  musUn  into  a  weighed  porcelain  dish,  add 
2  grams  of  glycerol  and  then  evaporate  down  to  24  grams.     In  usmg  this  gum  a  bundle 


REAGENTS  FOR  TESTING  FIBERS  871 

of  fibers  is  arranged  in  as  parallel  a  form  as  possible,  then  saturated  with  the  gum 
solution  and  well  dried.  The  stiff  mass  of  gum-imbedded  fibers  is  then  clamped 
tightly  between  two  pieces  of  cork  and  suitable  cuts  are  made  Avith  the  razor  of  a 
microtome. 

(32)  Congo  Red. — Behrens  uses  a  solution  of  Congo  Red  in  hot  water  made  slightly 
alkaline  with  soda  ash  for  the  staining  of  flax  and  hemp  fibers,  as  these  yield  strongly 
dichroic  colors  for  observation.  By  observation  of  the  stained  fibers  under  the  polaris- 
ing attachment  of  the  microscope  the  structure  of  the  fiber  may  be  seen.  The  colors 
are  weaker  in  the  case  of  straw,  esparto,  wood  and  jute,  while  cotton  shows  hardly  any. 

(33)  Copper-glycerol  Solution. — Used  by  Silbermann  and  Truchot  for  the  dis- 
tinction between  artificial  and  natural  siU-cs.  Dissolve  10  grams  of  copper  sulfate  in 
100  cc.  of  water,  then  add  5  grams  of  glycerol  and  sufficient  caustic  potash  solution  to 
completely  dissolve  the  precipitate  that  is  at  first  formed. 

(34)  Litmus  Paper. — Both  red  and  blue  are  useful.  Employed  to  distinguish 
between  vegetable  and  animal  fiber  in  the  dry  distillation  test;  the  gases  evolved 
from  vegetable  fibers  being  acid  in  character  and  those  from  animal  fibers  alkaline. 

(35)  Malachite  Green. — Used  by  Behrens  in  an  aqueous  solution  slightly  acid- 
ulated with  acetic  acid.  This  solution  colors  silk,  wool,  jute  and  woody  fiber  fast 
to  water;  hemp  and  Manila  fibers  partly  fast;  flax,  cotton,  straw,  esparto  and  pure 
cellulose  give  colors  readily  washed  out.  Klemm  uses  a  saturated  aqueous  solution 
of  Malachite  Green  containing  2  percent  of  acetic  acid  for  the  determination  of  the 
lignifi cation  of  wood  cellulose.  Completely  bleached  cellulose  shows  scarcely  any 
color;  half  bleached  appears  a  sky  blue;  and  the  unbleached  cellulose  is  colored  a 
deep  green. 

(36)  Methylene  Blue. — Also  used  by  Behrens  to  distinguish  between  flax  and 
cotton,  and  is  of  especial  importance  when  combined  with  the  oil  test. 

(37)  Alpha-naphthol. — Dissolve  20  grams  of  the  naphthol  in  100  cc.  of  alcohol. 
Used  to  distinguish  between  vegetable  and  animal  fibers.  About  0.1  gram  of  the  fiber 
sample  is  treated  with  1  cc.  of  water,  2  drops  of  the  naphthol  solution  and  1  cc.  of  con- 
centrated sulfuric  acid.  Vegetable  fiber  quickly  dissolves  and  on  shaking  gives  a 
deep  violet  color.     Animal  fiber  colors  the  liquid  yellow  to  reddish  brown. 

(38)  Naphthol  Yellow  S. — Used  in  combination  with  Croceine  Scarlet  7BN  by 
Behrens  for  the  distinction  between  silk,  wool,  jute  and  Manila  hemp.  The  sample 
of  fiber  is  colored  in  a  hot  solution  of  Naphthol  Yellow  S  containing  a  little  sulfuric 
acid  and  then  washed  with  hot  water.  It  is  then  colored  again  in  a  cold  solution  of 
Croceine  Scarlet  7BN  strongly  acidulated  with  sulfuric  acid.  At  first  the  silk  and 
later  the  jute  and  the  Manila  are  colored  red;  the  wool  remains  for  a  long  time  with 
a  citron  yellow  color.  Dilute  ammonia  will  strip  the  color  from  the  jute  and  the 
Manila. 

(39)  Beta-naphthylamine  Hydrochloride. — Used  for  coloring  lignified  cell  mem- 
branes an  intense  orange  yellow.  Dissolve  a  small  granule  of  the  salt  in  a  few  cc. 
of  warm  water. 

(40)  Phloroglucitwl. — Dissolve  1  gram  of  the  reagent  in  80  cc.  of  alcohol.  Used  in 
combination  with  hydrochloric  for  the  detection  of  lignin  or  to  mark  the  presence  of 
lignified  membranes  in  cells  (reddish  violet  color). 

(41)  Rosaniline  Sulfate. — Used  by  Klemm  to  distinguish  between  sulfite  and  soda 
cellulose.  A  saturated  solution  of  the  salt  in  a  2  percent  solution  of  alcohol  is  used 
and  sulfuric  acid  is  added  gradually  until  a  violet  tone  appears.  With  this  reagent 
unbleached  sulfite  cellulose  gives  a  deep  violet  red  color;  bleached  sulfite  cellulose 
shows  a  less  intensive  red  color;  unbleached  soda  cellulose  shows  about  the  same  but 
weaker;  bleached  soda  cellulose  is  not  colored  at  all  or  only  very  slight  red.  The 
difference  between  bleached  sulfite  and  unbleached  soda  cellulose   is  then  shown   by 


872  GENERAL   ANALYSIS   OF   THE   TEXTILE   FIBERS 

treatment  with  Malachite  Green,  the  sulfite  cellulose  giving  a  weak  blue  or  no  color 
at  all  while  the  unbleached  soda  cellulose  gives  a  very  perceptible  green  color. 

(42)  Safranine. — When  fibers  are  treated  with  a  neutral  warm  Safranine  solution 
and  then  rinsed,  silk,  wool,  woody  tissue,  and  jute  appear  under  the  microscope  a 
dark  rose  color;  cotton  a  dull  violet  red;  flax  and  hemp  yellowish  red. 

(43)  Schulze's  Maceration  Mixture. — This  is  used  for  isolating  fiber  elements.  It 
consists  of  concentrated  nitric  acid  containing  a  small  quantity  of  potassium  chlorate 
dissolved.  The  fiber  mass  is  heated  in  this  liquor  and  then  well  washed.  It  rapidly 
destroys  lignin  and  also  has  a  powerful  action  on  the  cellulose. 

The  color  reactions  of  the  vegetable  fibers  based  on  the  use  of  chemical 
reagents  are  often  not  very  definite  and  lead  to  inconclusive  results. 
There  have  been  many  reagents  suggested,  such  as  ammonia  and  hypo- 
chlorite to  characterise  jute;  nigrosine  and  cyanosine  and  other  stains 
to  distinguish  linen  from  hemp  and  cotton,  but  generally  these  furnish 
only  inconclusive  results.  The  reason  for  this  is  rather  easy  to  under- 
stand since  such  color  reactions  are  generally  due  to  the  presence  of  incrust- 
ing  substances  which  nearly  always  surround  the  raw  fibers,  but  those 
fibers  which  may  have  undergone  some  treatment  such  as  scouring  or 
bleaching  may  be  considerably  modified  in  this  respect,  and,  in  fact,  may 
be  entirely  devoid  of  foreign  incrusting  matter.  Instead  of  characterising 
or  distinguishing  one  vegetable  fiber  from  another  some  of  these  chemical 
reagents  may  be  usefully  employed  to  determine  if  the  fiber  is  raw  or  has 
undergone  a  cleansing  treatment. 

Some  of  the  chemical  reagents  which  furnish  the  more  hopeful  color 
reactions  and  which  are  especially  useful  in  differentiating  one  group 
from  another  are  the  following: 

(1)  Nitric  acid  containing  nitrous  oxide  gas.  This  reagent  colors 
the  so-called  woody  fibers  (lignin)  reddish  brown,  including  straws,  jute, 
marshmallow,  Manila  hemp,  cocoanut,  agave.  New  Zealand  flax.  It 
gives  yellowish  colors  with  fibers  composed  of  woody  cellulose  mixed 
with  others  that  are  not  so  woody,  such  as  esparto,  stipa  and  pineapple. 
It  leaves  almost  colorless  those  fibers  only  slightly  incrusted  and  more 
or  less  devoid  of  woody  substances  or  resinous  gums,  such  as  broom, 
sunn  hemp,  calotropis,  mulberry,  ramie,  hemp,  linen  and  cotton. 

(2)  Aniline  sulfate  dissolved  in  water  gives  an  intense  golden-yellow 
color  to  the  ligneous  fibers  such  as  jute  and  marshmallow,  an  intense 
canary-yellow  color  to  vegetable  silks,  and  a  pale,  yellowish  color  to  New 
Zealand  flax,  papyrifera,  sunn  hemp,  pineapple,  esparto,  and  stipa;  only 
a  very  slight  yellowish  tint  with  Manila  hemp,  cocoanut  and  raphia; 
and  no  reaction  with  cotton,  linen,  ramie,  even  if  in  the  raw 
state. 

Since  the  color  reactions  are  due  to  the  presence  of  ligneous  matter, 
the  color  diminishes  in  intensity  as  this  becomes  less  or  where  the  layers 
are  thin;    and  in  some  cases  the  ligneous  tissue  may  be  covered  with  a 


IIUTHENIUM  RED  AS  A  REAGENT  FOR  TESTING  TEXTILE  FIBERS     873 

siliceous  layer  which  greatly  diminishes  or  entirely  prevents  the  develop- 
ment of  the  color,  as  in  Manila  hemp,  cocoaniit  and  straw. 

(3)  Cochineal  in  alcohol  solution  colors  cotton  a  light  red,  while  linen 
gives  a  violet  color. 

(4)  Phloroglucinol  dissolved  in  water  colors  raw  flax  a  pale  reddish 
or  yellowish  which  turns  to  a  yellow  in  a  few  minutes.  Raw  hemp 
assumes  a  pale,  red  color  and  in  a  few  minutes  turns  to  a  light  wine  red. 

5,  Ruthenium  Red  as  a  Reagent  for  Testing  Textile  Fibers. — 
Ruthenium  is  one  of  the  rare  metals,  and  is  little  known  even  to  the 
majority  of  chemists.  Most  of  its  salts  give  an  intensely  red  colored 
solution  in  water,  and  this  is  especially  true  of  the  ammoniacal  oxychlo- 
ride  of  ruthenium;  hence  the  name  of  Ruthenium  Red  given  to  this  latter 
compound.    Its  chemical  formula  is  Ru2(OH)2  CI4  (NH3)7+3H20. 

It  has  been  found  that  this  salt  is  a  very  convenient  reagent  to  employ 
in  connection  with  the  microscopical  examination  of  textile  fibers.  This 
is  especially  due  to  the  fact  that  Ruthenium  Red  is  soluble  in  water  with 
a  violet  red  color,  but  is  insoluble  in  both  glycerol  and  alcohol.  On  the 
other  hand,  Methylene  Blue  and  most  other  coloring  matters  used  for 
staining  fibers  in  microscopic  work  are  easily  soluble  in  alcohol  or  glycerol, 
and  as  a  consequence  the  fiber  becomes  decolorised  when  treated  with 
these  liquids.  A  fiber  stained  with  Ruthenium  Red,  however,  is  not 
decolorised,  and  hence  may  be  employed  for  staining  in  a  glycerol  medium. 

Ruthenium  Red  is  without  action  on  fresh  lignified  tissue  or  that  pre- 
served in  alcohol,  but  after  the  action  of  alkalies  or  of  hypochlorite  of  soda 
the  tissue  is  colored  a  bright  rose.  Schwalbe,  however,  has  pointed  out 
that  the  variations  in  color  shades  are  very  slight,  and  as  a  test  for 
lignocellulose  staining  with  Ruthenium  Red  is  of  no  value,  as  aU  celluloses 
acquire  a  lilac-red  color  after  fifteen  minutes  action  of  the  reagent. 
Ruthenium  Red  colors  the  gums  and  pectin  matters  so  widely  disseminated 
through  vegetable  fibers,  whereas  pure  cellulose  (such  as  the  normal 
cellulose  of  cotton)  does  not  give  a  color.  Therefore,  if  raw  unbleached 
cotton  is  in  question  the  fiber  will  be  quickly  colored  on  account  of  the 
presence  of  the  pectin  or  cuticle.  In  the  same  manner,  those  textile  fibers 
containing  pectocelluloses,  such  as  linen,  ramie,  hemp  and  jute  are 
strongly  colored.    Raw  kapok  fibers  are  practically  not  stained  at  all. 

For  the  testing  of  textile  fibers  the  solution  of  Ruthenium  Red  may 
be  prepared  as  follows:  One  centigram  of  the  reagent  is  dissolved  in 
10  cc.  of  water.  As  this  solution  is  rather  unstable  in  strong  light,  it  is 
best  to  prepare  it  in  small  quantities  for  immediate  use.  In  the  micro- 
scopic test  a  drop  of  the  Ruthenium  Red  reagents  is  placed  on  the  object 
glass;  the  fibers  to  be  examined  are  then  immersed  in  the  reagent,  aftei- 
which  the  cover  glass  is  placed  in  position.  Since  the  Ruthenium  Red 
coloration  is  insoluble  in  alcohol,  the  colored  specimens  may  be  preserved 


874  GENERAL   ANALYSIS   OF   THE   TEXTILE   FIBERS 

in  alcohol.  By  employing  various  reagents  (acids,  alkalies,  dyestuffs, 
etc.)  simultaneously  with  the  ruthenium  reagent  some  very  interesting 
observations  may  be  made  under  the  microscope. 

The  following  table  exhibits  the  principal  reactions  of  textile  fibers 
with  the  Ruthenium  Red  reagent. 

A.  Fibers  of  Vegetable  Origin 

1.  Raxv  Egyptian  Cotton. — Rose  color  rapidly  developing  and  becoming  accentuated 
in  time.  After  several  hours  the  liquid  is  completely  decolorised  and  the  fiber  is  a 
violet  red. 

2.  Raw  American  Cotton. — Same  results  as  with  Egyptian  cotton,  only  the  colora- 
tion is  not  as  strong. 

3.  Bleached  Egyptian  Cotton. — No  coloration.  After  some  hours  the  liquid  is  still 
colored  and  the  fibers  remain  colored.  This  is  the  characteristic  reaction  for  normal 
cellulose  of  cotton. 

4.  Bleached  Absorbent  Cotton. — No  coloration  at  all.     Same  result  as  above. 

5.  Raw  Mercerised  Egyptian  Cotton. — Rapid  rose  coloration;  after  several  hours 
becoming  violet  red. 

6.  Bleached  Mercerised  Cotton. — The  fiber  remains  colorless,  even  after  several 
hours. 

7.  Bleached  Cotton  Mercerised  Immediatehj  Before  Examination. — The  fiber  is 
immediately  colored  a  pale  rose  red,  becoming  accentuated  to  a  violet  red  after  several 
hours.  As  mineral  acids  decolorise  the  ruthenium  reagent,  it  is  necessary  to  be  careful 
in  these  preparations  to  use  fibers  that  are  completely  neutralised  and  well  washed  in 
alkaline  water,  and  then  mixed  in  fresh  water. 

8.  Filter  Paper  oj  Pure  .Cellulose. — The  fibers  remain  almost  colorless,  even  after 
several  hours. 

9.  Ordinary  White  Filter  Paper. — Most  of  the  fibers  remain  colorless,  though  some 
are  colored  a  bright  rose. 

10.  Bleached  Wood-pulp  Made  icith  Bisulfite. — Coloration  irregular  and  some  fibers 
remain  colorless. 

11.  Raw  Wood-pulp  Made  urith  Bisulfite. — Irregular  coloration;  some  fibers  remain- 
ing colorless,  though  not  to  same  extent  as  with  the  bleached  pulp. 

12.  Raw  Soda  Pidp. —Yery  irregular  coloration.  The  general  tone  of  the  color 
being  darker  than  the  preceding. 

13.  Raiv  Linen. — Fibers  irregularly  colored  from  pale  rose  to  dark  red.  Some 
fibers  remain  colorless  at  first,  then  become  colored. 

14.  Bleached  lAnen. — Fibers  almost  colorless;  a  few  a  pale  rose. 

15.  Raw  Ramie. — Fibers  very  slightly  colored;  after  a  few  hours  a  general  pale  rose 
coloration. 

16.  Bleached  Ramie. — No  inunediate  coloration;  after  twelve  hours  only  a  slight 
rose  color. 

17.  Rav)  Hemp. — Coloration  irregular;  from  pale  rose  to  dark  red,  becoming  accen- 
tuated after  a  time. 

18.  Bleached  Jute. — Coloration  very  clear  red,  becoming  accentuated  after  a  time 
to  a  violet  red. 

B.   Animal  Fibers 

19.  Bleached  Wool. — Is  not  colored  even  after  twelve  hours'  contact  with  the 
reagent. 


GENERAL  TESTS   FOR   VEGETABLE   FIBERS 


875 


20.  Bleached  Silk. 
colored  a  rose  red. 


-Also  colorless  at  first,  but  after  a  time  the  filaments  become 


C.  Artificial  Silk 


While  it  is  possible  to  distinguish  nicely  between  artificial  silk  made  from  nitro- 
cellulose and  those  made  from  viscose  and  cuprammonium  solutions  by  means  of 
Methylene  Blue,  it  is  not  possible  to  differentiate  between  the  last  two  silks  by  this 
reagent.  By  the  use  of  the  ruthenium  red  reagent,  however,  it  is  possible  to  dis- 
tinguish between  viscose  silk  and  cuprammonium  silk.  The  former  fiber  is  colored  a 
bright  rose,  while  the  latter  remains  almost  colorless. 

By  reference  to  the  above  list  of  reactions,  it  will  also  be  noticed  that 
it  is  possible  to  distinguish  between  raw  American  cotton  and  bleached 
Egyptian  cotton. 

The  behavior  of  various  vegetable  fibers  with  Ruthenium  Red  as 
compared  with  several  other  reagents  is  described  by  Haller.^  The  results 
are  given  in  the  following  table: 


Cotton. 

Nettle, 

Flax, 

Broom. 

Hemp, 

Bullrush, 

Lupin . 

Cotton 

Grass 

(Eriophor- 

mium) . 

Khaki 
Cotton. 

Jute. 

Iodine  solution 

Cellulose 
reaction 

Cellulose 
reaction 

Cellulose 
reaction 

Yellow- 
brown 
color 

Yellow- 
brown 
color 

Yellow- 
brown 
color 

Ruthenium  Red 

No  color 

Red  color 

Red  color 

— 

Red  color 

Red  color 

Phlorogucinol+HCl 

No  color 

No  color 

Pale  rose 

— 

Red  color 

Maules  reaction 

— 

— 

— 

— 

— 

+ 

Ferric    chloride    and 
Potassium       Ferri- 
cyanide 

Pale  blue 

+ 

+ 

6.  General  Tests  for  Vegetable  Fibers. — A  large  number  of  the  textile 
vegetable  fibers  (from  either  bast  or  leaf  tissues)  are  more  or  less  lignified — 
that  is  to  say,  a  part  of  the  fiber  is  changed  somewhat  into  woody  tissue. 
This  affords  a  means  of  distinguishing  certain  fibers  from  others,  or  rather 
one  class  of  fibers  from  another.  If  a  lignified  fiber  is  treated  with  a 
solution  of  indol  and  then  with  hydrochloric  acid,  a  red  color  is  produced. 
Aniline  sulfate  or  hydrochloride,  as  well  as  many  other  similar  compounds, 
colors  lignified  tissues  a  golden  yellow,  especially  is  subsequently  treated 

1  Farb.  Zeit.,  1919,  pp.  29  and  43. 


876  GENERAL   ANALYSIS   OF   THE   TEXTILE   FIBERS 

with  dilute  hydrochloric  acid.  Phloroglucinol  and  hydrochloric  acid  give 
a  red  color;  naphthylamine  hydrochloride  an  orange  color,  etc.  It  is  to 
be  remarked,  however,  that  not  infrequently  cross-sections  of  the  fibers 
though  strongly  lignified  give  scarcely  any  color  at  all  with  the  specific 
woody  fiber  reagents.  Jute  is  an  example  of  this;  for  with  phloroglucinol 
or  indol  and  hydrochloric  acid  it  scarcely  gives  any  color,  while  with 
iodine  and  sulfuric  acid  it  gives  a  beautiful  yellow  color;  although  when 
viewed  lengthwise  it  shows  a  strong  lignification. 

If  single  bast  or  sclerenchymous  fibers  (from  leaf  tissue)  are  to  be 
investigated,  the  fiber  bundles  must  be  disintegrated  into  their  constituent 
parts  by  maceration.  This  can  be  accomplished  by  boiling  the  fibers 
with  dilute  nitric  acid,  or  with  Schulze's  mixture  (nitric  acid  mixed  with 
potassium  chlorate),  or  with  caustic  potash.  By  this  treatment,  however, 
the  woody  matter  is  destroyed,  and  the  fibers  are  somewhat  swollen 
(especially  with  caustic  potash),  so  that  their  microchemical  reactions 
are  affected,  as  well  as  their  diameters.  The  separation  of  the  fiber  bundles 
into  their  elements  may  also  be  undertaken  on  the  object  slide  by  treat- 
ment with  cold  chromic  acid  solution.  This  solution  is  allowed  to  act  for 
several  minutes,  then  water  is  added,  and  the  fiber  elements  are  finally 
separated  from  one  another  completely  by  squeezing  down  the  cover  glass. 
By  the  use  of  this  method  there  is  no  swelling  to  distort  the  fiber,  but  the 
woody  matter  is  dissolved  as  when  nitric  acid  is  used.  The  method  of 
Vetillard  appears  to  be  a  very  good  one,  since  by  its  use  the  microchemical 
reactions  are  not  affected.  The  method  consists  in  boiling  the  fibers  to 
be  tested  with  a  10  percent  solution  of  soda  or  potash  for  about  one-half 
hour,  then  washing  well  in  water,  and  rubbing  between  the  fingers,  when 
a  complete  disintegration  is  effected  and  objectionable  attached  matter  is 
also  removed.  The  fibers  so  treated  can  then  be  mounted  in  glycerol  or 
subjected  to  the  iodine  and  sulfuric  acid  reaction. 

The  observation  of  the  cross-section,  which  is  essential  to  the  thorough 
study  of  the  fibers,  requires  the  preparation  of  thin  sections.  In  order 
to  do  this  a  small  bundle  of  fibers  is  arranged  as  parallel  as  possible,  and 
then  impregnated  with  a  thick  solution  of  glycerol  containing  dissolved 
gum,  after  which  it  is  allowed  to  thoroughly  dry.  The  gum  solution 
should  contain  neither  too  much  nor  too  little  glycerol.  If  the  former, 
the  bundle  of  fibers  will  not  harden,  and  if  the  latter,  it  will  crack  on  drying 
and  break  during  treatment  in  cutting  the  cross-section.  The  bundle  of 
fibers  is  laid  between  two  corks,  and  pasted  in  securely  and  tied.  By 
means  of  a  sharp  razor  thin  cross-sections  may  be  cut  at  will,  which  as 
far  as  possible  should  be  cut  perpendicular  to  the  axis  of  the  fibers. 

7.  Distinction  between  Animal  and  Vegetable  Fibers.^ — The  simplest 
and  most  ready  test  for  this  purpose,  when  the  fibers  can  be  separated 
from  each  other,  is  to  burn  a  sample  of  the  material.     The  animal  fibers 


DISTINCTION    BETWEEN   ANIMAL  AND   VEGETABLE    FIBERS      877 

(wool  and  silk)  will  emit  a  strong  empyreumatic  odor  of  burning  feathers, 
whereas  the  vegetable  fibers  (cotton,  linen,  etc.)  will  give  ofT  no  such 
disagreeable  odor,  but  only  pungent  and  somewhat  acrid  fumes  similar  to 
those  from  burning  paper.  In  cases  where  animal  and  vegetable  fibers  are 
mixed  together  and  cannot  readily  be  separated,  the  burning  test,  of 
course,  fails  for  the  detection  of  the  vegetable  fiber,  though  the  presence 
of  the  animal  fiber  will  be  made  evident. 

A  delicate  reaction  ^  for  detecting  the  presence  of  vegetable  fibers  in 
wool  is  the  following:  The  sample  of  material  under  examination  is  well 
boiled  with  water  to  remove  any  finishing  materials  that  might  be  present 
and  interfere  with  the  reaction.  Then  a  small  portion  of  the  sample  is 
put  in  a  test-tube  with  1  cc.  of  water  and  2  drops  of  an  alcoholic  solution 
of  alpha-naphthol  and  about  1  cc.  of  concentrated  sulfuric  acid.  If 
vegetable  fibers  are  present,  they  will  be  dissolved  and  the  liquid  will 
acquire  a  deep  violet  color  when  shaken;  the  animal  fibers  only  give  a 
yellow  to  reddish  brown  coloration  but  no  violet  tint.  If  thymol  is  used 
instead  of  alpha-naphthol,  a  beautiful  red  coloration  will  be  produced  in 
the  presence  of  vegetable  fibers. 

Cross  and  Bevan  have  also  devised  a  delicate  test  which  is  serviceable  for 
detecting  the  presence  of  vegetable  fibers  in  fabrics;  the  sample  of  the 
cloth  is  immersed  in  a  solution  of  ferric  chloride,  squeezed,  and  then 
placed  in  a  solution  of  potassium  ferrocyanide,  when  any  vegetable  fiber 
present  will  be  colored  blue. 

Lieberman  gives  a  test  to  distinguish  between  animal  and  vegetable 
fibers  as  follows:  The  fibers  are  boiled  with  a  solution  of  Magenta  which 
has  previously  been  decolorised  by  the  addition  of  just  sufficient  caustic 
soda;  then  they  are  well  washed  and  placed  in  water  slightly  acidu- 
lated with  acetic  acid.  If  the  fibers  are  of  animal  origin,  they  will 
be  colored  a  deep  pink,  whereas  cotton  and  linen  fibers  will  be  un- 
affected. 

Both  this  reaction  and  the  one  with  picric  acid  (see  Table  II)  are 
convenient  to  use  when  it  is  desirable  to  render  visible  the  animal  fibers 
in  a  mixed  yarn  or  fabric.  In  case  of  a  mixture  of  wool  and  silk  fibers, 
the  wool  may  readily  be  shown  by  placing  the  sample  in  a  very  dilute 
boiling  solution  of  caustic  soda  containing  a  few  drops  of  lead  acetate 
solution.  Any  wool  present  will  be  turned  brown  by  this  treatment,  due 
to  the  formation  of  lead  sulfide  from  the  sulfur  which  forms  a  constituent 
of  this  fiber.  Silk  (and  also  cotton  or  other  vegetable  fiber)  will  not  be 
colored.  In  this  test,  of  course,  it  will  be  necessary  that  the  sample  is 
undyed,  or,  at  least,  that  all  coloring  matters  originally  present  be  com- 
pletely removed. 

J  Molisch,  Dingl.  Pohjl.  Jour.,  1886,  vol.  261,  p.  135. 


878  GENERAL   ANALYSIS   OF   THE   TEXTILE   FIBERS 

In  strong,  cold  sulfuric  acid  silk  quickly  turns  yellow  and  dissolves; 
cotton  disintegrates  slowly  without  color;  flax  and  hemp  make  a  black 
mixture,  and  wool  is  scarcely  affected.  Both  silk  and  wool  turn  yellow 
and  are  soluble  in  nitric  acid,  the  first  more  speedily,  while  vegetable 
fibers  are  slightly  affected.^ 

Behrens  furnishes  the  following  color  test  to  distinguish  the  several 
important  fibers.  It  depends  on  the  relative  reactions  of  these  fibers  with 
solutions  of  Malachite  Green  and  Benzopurpurine,  and  is  carried  out  as 
follows :  The  mixture  of  fibers  is  dyed  for  fifteen  minutes  in  a  warm  solution 
of  Malachite  Green,  then  washed  until  no  more  color  is  extracted.  It  is 
then  steeped  for  twenty  minutes  in  a  cold  solution  of  Benzopurpurine, 
and  thoroughly  washed  again.     The  following  result;:^  will  appear: 

(a)  Silk,  wool,  and  jute  (or  other  strongly  lignified  vegetable  fiber) 
will  be  colored  green.  The  silk  will  be  dyed  a  light  green  and  the  wool  and 
jute  a  dark  green. 

(6)  Hemp  and  Manila  hemp  (or  other  slightly  lignified  vegetable  fiber) 
will  be  colored  dirty  grayish  brown  (mud  color). 

(c)  Cotton  and  linen  will  be  colored  red.  The  cotton  will  show  a 
light  red  color  while  the  linen  will  be  dark  red. 

An  interesting  qualitative  test  to  distinguish  silk  from  wool  and  vegeta- 
ble fibers  is  the  following  given  bj^  Lecomte  •?  A  small  portion  of  the  fabric 
to  be  examined  is  soaked  in  dilute  nitric  acid  (100  grams  per  liter)  and  then 
treated  gradually  with  constant  stirring  during  three  minutes  with  30  cc. 
of  sodium  nitrite  solution  (50  grams  per  liter).  After  ten  minutes  the 
fabric  is  well  washed  and  cut  into  two  equal  portions.  The  first  of  these 
is  treated  for  one  hour  with  40  cc.  of  a  cold  solution  of  sodium  plumbite 
and  sodium  naphtholate.  This  solution  is  pi-epared  by  dissolving  50  grams  ij 
of  sodium  hydrate  in  500  cc.  of  water,  and  graduallj^  adding  25  grams  of 
lead  sub-acetate  dissolved  in  300  cc.  of  water.  When  the  resulting  solution 
is  clear  5  grams  of  beta-naphthol  are  added  and  the  solution  diluted  to 

1  liter.     The  second  portion  of  the  fabric  is  treated  with  40  cc.  of  a  solution 
containing  50  grams  of  sodium  hydrate,  25  grams  of  lead  sub-acetate  and 

2  grams  of  resorcin  per  liter.  After  treatment  for  one  hour  both  portions  ij 
are  washed  for  fifteen  minutes  in  water,  then  soaked  in  dilute  hydrochloric 
acid  (5  grams  per  liter)  again  washed  thoroughly,  then  pressed  between 
filter-paper  and  finally  dried  in  the  dark.  When  examined  under  the 
microscope  the  silk  fibers  will  appear  of  a  reddish  color,  the  wool  fibers 
will  be  black,  and  the  vegetable  fibers  colorless. 

Allen  summarises  in  Table  III  the  reactions  to  distinguish  silk  qualita- 
tively from  other  fibers. 

^  Seaman,  On  the  Identification  of  Fibers. 
^Jour.  Pharm.  Chem.,  1906,  p.  447. 


DISTINCTION   BETWEEN  ANIMAL  AND  VEGETABLE  FIBERS     879 

TABLE  III 

Test. 

Silk,  Wool,  Fur,  or  Hair. 

Cotton  or  Linen. 

Heated  in  a  small  test-tube 

Brittle,  carbonaceous  residue,  and 
odor  of  burnt  feathers.    Gases  and 
condensed    moisture    alkaline    to 
litmus 

Charring  and  smell  of 
burning  wood.  Gases 
and  condensed  mois- 
ture acid  to  litmus 

Boiled  on  a  saturated  aque- 
ous solution  of  picric  acid 
and  rinsed  in  water 

Dyed  yellow 

Unchanged 

Boiled  with   Millon's   rea- 
gent 

Red  coloration 

No  change  of  color 

Treated    with    cold    nitric 
acid  (1.2  sp.  gr.) 

Colored  yellow 

No  change  of  color 

Moistened  with  dilute  hy- 
drochloric acid  and  dried 
at  100°  C. 

Unchanged 

Becomes  rotten 

Heated  to  boiling  with  hy- 
drochloric acid 

Silk. 

Wool,  Fur,  or 
Hair. 

Dissolved 

Swells,  without  at 
once  dissolving 

Mostly  undissolved 

Boiled  with  a  cone,  solution 
of  basic  zinc  chloride 

Dissolved 

Unchanged 

Unchanged 

Treated  with  cold  Schweit- 
zer's reagent 

Dissolved;       not 
precipitated  by 
addition  of  salts 

Undissolved;  dis- 
solves on  heat- 
ing 

Dissolved ;   solution 
precipitated  by  addi- 
tion of  salts 

Treated  in  the  cold  with  10 
percent  caustic  soda 

Undissolved 

Dissolved 

Undissolved 

Boiled  with  a  2  percent  solu- 
tion of  caustic  soda 

Dissolved;    solu- 
tion not  dark- 
ened   by     lead 
acetate;    nega- 
tive      reaction 
with  sodium  ni- 
troprussidc 

Dissolved ;     solu- 
tion gives  black 
or  brown  precip- 
itate with  lead 
acetate  and  vio- 
let   color    with 
sodium      nitro- 
prusside 

Unchanged 

Behavior     with    Molisch's 

test 

Dissolved,     with 
little  coloration 

Undissolved,  with 
yellow  or  brown 
coloration 

Dissolved  with  deep 
violet  color 

880 


GENERAL   ANALYSIS   OF   THE   TEXTILE   FIBERS 


8.  Analjrtical  Reactions  of  Vegetable  Fibers. — The  following  analytical 
table  showing  the  reactions  of  the  more  important  vegetable  fibers  is  given 
by  Dodge: 


TABLE  IV 


Iodine  and 

Iodine  and 

Cupram- 

Aniline 

Phloro- 

Fiber. 

Zinc 
Chloride. 

Sulfuric 
Acid. 

monium. 

Sulfate. 

glucinol. 

Cotton 

Violet 

Blue 

Blue  solu- 
tion 

— 

— 

Flax            

do. 
do. 

do. 
do. 

do. 
do. 

Pale  yellow 



Hemp 

Violet  red 

Jute 

Brown  yel- 
low 

Green  blue 

do. 

Golden 
yellow 

Deep  red 

Ramie 

Dull  violet 
Yellow  to 

Dull  blue 

do. 

Yellow 



Manila  hemp 

Red 

violet 

New  Zealand  flax 

Golden 
yellow 

Green  blue 

Bluish 

Yellowish 

Pale  red 

Aloe 

Yellow  to 
brown 

Yellow 

Swells; 
bluish 

do. 

Pink 

Cocoanut 

do. 

— 

— 

Bright  yellow 

Purplish 

The  solution  of  iodine  and  zinc  chloride  is  prepared  by  taking  100 
parts  of  zinc  chloride  solution  of  1.8  specific  gravity,  adding  12  parts  of 
water  and  6  parts  of  potassium  iodide,  then  add  iodine  until  vapors  of  the 
latter  begin  to  form.  The  brown  liquid  thus  obtained  should  be  preserved 
away  from  light.  The  cuprammonium  solution  is  made  by  adding  sodium 
carbonate  to  a  solution  of  copper  sulfate,  whereby  a  mixed  precipitate  of 
copper  hydrate  and  carbonate  is  obtained.  This  is  well  washed,  and 
treated  with  just  sufficient  ammonia  (of  0.91  specific  gravity)  to  dissolve 
it.  The  solution  should  be  well  shaken  and  filtered  before  using.  The 
aniline  sulfate  is  used  as  a  1  percent  solution;  this  reagent  colors  cells  of 
woody  fiber  pale  to  deep  yellow  in  proportion  to  the  amount  of  woody 
matter  present.  The  phloroglucinol  reagent  is  applied  as  follows:  first 
a  drop  or  two  of  a  5  percent  solution  of  phloroglucinol  in  95  percent  alcohol 
is  applied  to  the  fiber  under  examination,  and  this  is  followed  by  the 
addition  of  a  couple  of  drops  of  strong  hydrochloric  acid.  Lignified  cells 
will  be  stained  red,  while  those  not  lignified  will  remain  colorless.  A 
similar  solution  of  aniline  hydrochloride  may  be  substituted  for  the 
phloroglucinol,  in  which  case  the  lignified  tissue  will  be  stained  yellow 


ANALYTICAL  REACTIONS  OF  VEGETABLE   FIBERS  881 

instead  of  red.  The  iodine  and  sulfuric  acid  is  applied  in  a  manner  similar 
to  that  described  on  a  previous  page. 

In  an  examination  of  a  sample  the  fibers  should  be  separated  into 
their  ultimate  cells  by  soaking  in  caustic  alkali,  then  rubbing  between 
the  fingers,  or  teasing  out  with  needles.  If  the  separation  of  the  cells  is 
difficult  by  this  means  recourse  must  be  had  to  boihng  the  fiber  in  a  10 
percent  solution  of  caustic  soda  or  Labarraque's  solution  (sodium  hypo- 
chlorite), and  then  fraying  the  fiber  apart  by  rubbing  in  a  mortar.  After 
the  fiber  has  been  divided  into  its  ultimate  cells,  they  should  be  spread 
out  on  a  slide  moistened  with  glycerol;  this  will  lessen  the  tendency  of 
the  cells  to  curl  up.  A  cover-glass  is  then  laid  on,  and  the  microscopical 
examination  is  made.  In  order  to  make  an  examination  of  the  section 
of  the  fiber  to  determine  the  diameter  of  the  cells,  the  following  method  is 
recommended:  An  imbedding  mass  is  made  by  dissolving  70  grams  of 
clean  gum  arabic  in  an  equal  weight  of  distilled  water;  then  4  grams 
of  isinglass  (gelatine)  are  digested  in  16  cc.  of  cold  water  till  swollen,  and 
heated  to  complete  solution.  One-haK  of  this  latter  solution  is  strained 
through  a  piece  of  fine  muslin  (the  rest  is  discarded)  and  mixed  with  the 
solution  of  gum  arabic;  10  to  12  cc.  of  glycerol  are  added,  the  whole  is  well 
mixed  and  warmed.  It  is  best  preserved  in  small  bottles  containing  a 
fragment  of  camphor.  On  cooling  the  mixture  solidifies,  but  when  it  is  to 
be  used  the  bottle  is  warmed,  a  small  bundle  of  fibers  for  examination 
are  tied  together  and  saturated  with  the  glue,  drawing  the  fibers  out  care- 
fully till  they  are  straight  and  parallel.  The  bundle  is  then  hung  up  and 
dried  for  twelve  hours,  after  which  it  will  be  firm  enough  to  cut  with  a 
microtome.  The  slices  thus  obtained  are  placed  on  a  sHde,  and  moistened 
with  the  iodine  solution;  this  dissolves  the  glue,  which  is  absorbed  by  strips 
^f  blotting-paper  and  thus  removed.  With  soft  fibers  that  are  easily  cut, 
a  section  may  be  more  simply  obtained  by  soaking  in  melted  paraffin, 
and,  after  cooling,  cutting  on  the  microtome.  The  wax  may  be  removed 
from  the  section  by  dissolving  in  benzene  or  turpentine. 

In  the  cutting  of  the  fiber  cross-sections  with  the  microtome,  care  must 
be  had  not  to  slice  the  cutting  too  thin;  for  in  the  color  reactions  that  are 
to  be  subsequently  obtained  with  the  sections,  satisfactory  color  dis- 
tinctions will  not  be  observed  if  the  section  is  too  thin,  as  there  will  not 
be  sufficient  depth  of  color.  On  the  other  hand,  the  sections  must  not 
be  too  thick  as  they  will  then  be  hard  to  properly  observe  in  the  mount 
and  the  color  will  be  too  dense  and  opaque  for  proper  comparison. 

Table  V  shows  the  reaction  of  the  various  vegetable  fibers  with  the 
iodine-sulfuric  acid  reagent,  together  with  the  length  and  diameter  of  the 
ultimate  fiber-cells  in  millimeters. 


882 


GENERAL   ANALYSIS   OF   THE   TEXTILE   FIBERS 


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MICRO-ANALYTICAL   TABLES   FOR  VEGETABLE  FIBERS 


883 


9.  Micro-analjrtical  Tables  for  Vegetable  Fibers. — The  following  micro- 
analytical  tables  have  been  adapted  from  Hohnel  for  the  qualitative 
determination  of  vegetable  fibers. 


I.    TABLE  FOR  THOSE  VEGETABLE  FIBERS  BOTANICALLY 
DESIGNATED  AS  HAIR  STRUCTURES 

1.  (a)  Each  single  fiber  consists  of  a  single  cell (see  4) 

(b)  Each  fiber  consists  of  two  cells,  namely,  a  short,  thick,  underlying  cell,  and  an 
overlying  pointed,  principal  cell.  The  fibers  are  grayish  brown,  scarcely  0.5  cm.  long; 
hard,  woolly,  lifeless,  thin-walled,  but  round-stapled.  Such  fibers  form  the  thick  upper 
coating  on  the  leaves  of  the 
CycadaxB  macrozamia  of  New 
South  Wales,  and  are  used 
as  vegetable  hair  in  upho- 
lstery. 

(c)  Each  single  fiber  con- 
sists of  a  series  of  cells,  hence 
is  a  cellular  fiber.  The  cells 
are  golden  yellow  to  brown 
in  color,  generally  clinging 
together  and  empty.  The 
fiber  as  a  whole  is  highly 
lustrous,  but  very  harsh  and 
brittle;  very  thin-walled,  flat 
and  ribbon -shaped;  fre- 
quently twisted  on  its  axis; 
broad  and  0.5  to  2  cms. 
long.  Such  fibers  form  the 
thick  coating  on  the  leaves 
of  various  ferns  {Cibotium) 
in  Asia,  Australia,  and  Chili. 
The  material  is  used  for 
upholstery  under  the  name 
oipulu  (Fig.  377). 

(d)  Each  fiber  consists  of  numerous  cells  growing  side  by  side,  or  of  several  series 
of  such;  forms  the  so-called  tuft (see  2) 

2.  (o)  Hairs  straight,  stiff;  white  to  dirty  yellow  in  color (see  3) 

(6)  Hairs  woolly,  tough,  brownish  violet  in  color,  4  to  6  mm.  long;    consisting  of 

long  cotton-like,  flat,  twis  ed,  spiral  cells,  the  walls  of  which  are  frequently  thick  and 
undulating;  the  contents  of  the  cells  moderately  abundant,  yellow  to  violet,  and  in 
part  colored  red  with  hydrochloric  acid.  This  fiber  covers  the  small,  egg-shaped, 
flattened  fruit  of  the  New  Holland  plant  Cryptostcmma  calendidaceum.  It  is  used  in 
Australia  as  a  stuffing  material. 

(c)  Hairs,  woolly  harsh,  reddish  yellow  in  color;  the  cells  are  very  thin-walled, 
colorless,  and  generally  empty;  in  places,  however,  filled  with  a  homogeneous  reddish 
yellow  substance;  where  two  cells  come  together  side  by  side  there  are  to  be  noticed 
round  spots.  The  individual  cells  are  relatively  broad,  extremely  varied  and  irregu- 
larly thick;  irregularly  bent  in  places  and  frequently  knitted  together.  This  fiber 
forms  the  coating  of  a  plant  {Hibiscus  ?)  growing  in  Cuba;  as  employed  for  upholstery 
materials  it  goes  by  the  jiame  of  Majagua. 


Fig.  377. — Vegetable  Silk  from  Cibotium  glaucum. 
(Solaro.) 


884 


GENERAL   ANALYSIS   OF   THE   TEXTILE   FIBERS 


3.  (a)  The  hairs  are  1  to  3  cm.  long,  and  on  the  average  are-  under  50  microns  wide; 
they  consist  of  two  layers  of  cells  which  grow  into  one  another.  The  inner  walls  are 
rough;  the  outer  walls  are  thin  and  indented,  hence  he  close  against  the  inner  portion; 
the  section  walls  are  quite  noticeable  and  thick;  the  tufts  end  in  2  to  6  pointed,  often 
hook-shaped  cells;  the  end  cells  show  numerous  pores;  weakly  lignified.  This  fiber 
consists  of  the  ripe  fruit  spicula  of  cotton  grass,  Eriophorum  angustifolium,  E.  MifoUum, 
etc Cotton  grass  (Figs.  378,  379) 


Fig.    378. — Cotton    Grass     {Eriophorum 
angustifolium).     (Dodge.) 


Fig.  379. — The  Lesser  Cotton  Grass  (Erio- 
phorum latifolium) .     (Dodge.) 


(b)  The  fibers  are  5  mm.  long;  mean  breadth  of  the  tufts  8  to  16  microns,  the 
widest  being  under  30  microns;  the  tufts  do  not  end  with  sharp-pointed  cells;  the 
section-walls  under  low  magnification  appear  as  httle  knots  and  are  us  ally  quite 
noticeable.  This  fiber  is  obtained  from  the  small,  lance-like  fruit  of  the  reed  mace, 
Typha  angustifoUa,  which  grows  on  a  small  shaft,  and  carries  the  hairs  on  the  other 
end.     It  is  used  for  upholstery  and  other  filling  material.  .  .Reed-mace  hair  i  (Fig.  380) 

1  Reed-mace  hair  is  also  known  as  perigon  hair;  it  is  made  into  a  good  quality  of 
felt.  The  fiber  consists  of  a  few  series  of  ce'ls,  elongated  and  thin- walled.  The  cell- 
walls  project  in  a  tooth-Uke  manner,  especially  near  the  point  of  the  fiber.  The  fiber 
is  slightly  hgnified. 


MICRO-ANALYTICAL   TABLES   FOR   VEGETABLE   FIBERS         885 


4.  (a)  The  fibers  are  flat,  woolly,  frequently  twisted  in  a  spiral  manner  on  their  axes; 
not  lignified (see  5) 

(6)  The  fiber  is  generally  cylindrical,  stiff,  not  twisted;    somewhat  lignified,  hence 
colored  red  with  indophenol  or  phloroglucinol (see  6) 

5.  (a)  Fibers  1  to  5  cm.  long;  white  to  yellowish  brown;    12  to  42  microns  thick. 

Cotton  (Fig.  381) 


Fig. 


Fig.  380.  Fig.  382. 

380.— Reed-mace  Hair.     (X340.)     (Hohnel.)     A,  Portion  of  hair;    B,  ripe  fruit 
at  /;  h,  hair  around  fruit;  z,  cells;  k,  kxiotted  structure. 
Fig.    381. — Cotton    Fibers.     (X170.)     Various    cotton    fibers    with    sections    above. 

I,  Lumen;  d,  twists;  s,  granulations  on  cuticle.     (Hohnel.) 

Fig.  382. — Fibers  of  Cotton  Grass  or  Vegetable  Silk.     The  sharp  fractures  show  the 

brittle  nature  of  the  fiber.     (Micrograph  by  author.) 


(b)  Fibers  only  9.5  cm.  long;   very  tliin;   usually  consisting  of  tufts;  violet-brown  in 

color.     See  above,  under  2  (6) Cnjptosfemnm  hairs 

6.  (a)  The  product  consists  of  grassy  spicula  with  a  hairy  covering;  the  hairs  are 
5  to  8  mm.  long  and  about  10  to  15  microns  wide;  the  thickness  of  the  wall  of  the 
thick,  cylindrical-pomted  hairs  remains  rather  uniform  up  to  the  point  itself,  hence 


886 


GENERAL   ANALYSIS   OF   THE   TEXTILE   FIBERS 


the  latter  appears  very  thick;    spots  are  often  observed.     This  fiber  is  upholstery 

material  from  Saccharum  officinale Sugar-cane  hairs 

(b)  The  product  consists  of  short  white  fibers,  about  8  to  24  microns  in  width,  and 
of  oval,  flat  fruit-shells,  4  mm.  wide  and  5  mm.  long;  the  hairs  are  broadened  at  the 
base,  hence  generally  knife-shaped;  thick-walled,  with  transverse,  fissure-like  marks; 
the  upper  portion  of  the  hair  is  very  thin  and  rough-walled;    colorless;    the  ends  are 

usually  blunt  and   contain   a  granular  matter; 
slightly  lignified,  especially  at  the  base. 

Poplar  cotton 
(c)   The  product  consists  entirely  of  hairs  and 
^  ^^^                                         is  almost  entirely  free  from  accidental  impuri- 
ties   Vegetable  down  and  silk 

7.  (a)  The  fibers  have   two    to    five   longitudi- 
nal   ridges    on    the    walls,    which    are    either 
crescent-shaped    or    quite    flat,     running    into 
bf      &  network  at  the  base;    these  ridges  are  broad 

and  difficult    to    discern    in    a   surface  view  of 

Fig.     383. — Fiber    of    Strophanthus.    the   fiber,  yet   sometimes    very  apparent;    the 

(X300.)      a,    Longitudinal     view;    maximum  thickness   about   35   microns;    white 

b,   cross-section.      (Micrograph  by    or   yellowish    in    color.     These    fibers    are    the 

author.)  seed-hairs  of  Apocynum  and  Asclepias. 

Vegetable  silk  (Fig.  382) 
(b)  The  fibers  are  without  ridges;    transverse  ridges  frequently  at  the  base  or    as 
a  network.     Ma.ximum  thickness  generally  under  35  microns;    yellowish  to  brown. 
These  fibers  consist  of  the  hairs  which  cover  the  fruit-pods  of  Bombacea;. 

Vegetable  down  (see  13) 

8.  (a)  The  hairs  are  3.5  to  4.5  cm.  long,  and  the  largest  are  50  to  60  microns  in  diame- 
ter   (see  9) 

(6)   The  fibers  are  1.5  to  4  cm.  long,  and  the  largest  are  35  to  45  microns  in  diameter. 

(see  10) 

9.  (a)  The  fibers  are  narrowed  at  the  base,  and  directly  above  are  strongly  swollen, 
and  up  to  100  microns  in  thickness;  numerous  pores  at  the  base;  the  fibers  grow 
brush-like  on  a  stem,  are  yellowish  and  harsh.     This  is  vegetable  silk  from  Senegal. 

Strophanthus  (Fig.  383) 
(b)  The  fibers  are  white,  firm,  and  tough,  not  harsh;    form  a  hairy  tuft  or  crown. 

This  is  vegetable  silk  from  India Bcaunwntia  grandiflora  (Fig.  384) 

(c)   Yellow  rod  fibers,  weak,  stiff,  straight,  and  harsh. . . .  Calotropis  procera,  Senegal 

10.  (o)  At  base  of  the  hair  there  are  spots  or  pores (see  11) 

{b)  Spots  or  pores  lacking.     Vegetable  silk  from  Asclepias  cornuti,  curassavica,  etc. 

(Fig.  385) 
This  plant  grows  in  tropical  and  sub-tropical  America,  and  is  also  found  in  India. 
Its  seed-hairs  are  said  to  be  stronger  than  those  of  most  other  varieties  of  such  fibers. 

11.  (a)  Spots  large;  roimd  or  oblique;  the  walls  of  the  fiber  are  not  thicker  at  the 
base  than  at  the  upper  portion;  the  ridges  on  the  fiber  are  remarkably  well  developed, 
the  hairs  are  strongly  bent  back  at  the  base.     Vegetable  silk  from  Calotropis  gigantea. 

(b)  Spots  small,  no  longitudinal  markings;   walls  thicker  than  the  foregoing  fiber; 
ridges  less  noticeable  and  often  apparently  lacking (see  12) 

12.  (a)  Hairs  narrowed  at  the  base Hoya  liridijlora 

(b)   Hairs  not  narrowed  at  all,  or  scarcely  so Marsdenia 

13.  (a)  The  hairs  have  mesh-like  ridges  at  the  base  situated  obliquely  or  have  spiral 
ridges (see  14) 

(b)  Without  mesh-like  ridges  at  the  base (see  15) 


MICRO-ANALYTICAL  TABLES   FOR   VEGETABLE   FIBERS         887 


Fig.  384. 


Fig.  385. 


Fig.  384. — Vegetable  Silk  from  Beaumontia  grandiflora.  (X170.)  h,  Base  of  fiber; 
s,  pointed  ends;  q,  cross-section;  m,  middle  portion  of  fiber;  w,  cell-wall;  I,  longi- 
tudinal ridges.     (Hohnel.) 

S'iG.  385. — Vegetable  Silk  from  Asclepias  cornuti.  (X300.)  a,  Longitudinal  view; 
b,  cross-sections;  r,  thickened  ridges;  w,  cell-wall.     (Micrograph  by  author.) 


Fig.  386. — Vegetable  Down  {Bomhnx  ceiba).     (X300.)     (Micrograph  by  author.) 


GENERAL   ANALYSIS   OF   THE   TEXTILE   FIBERS 


14.  (a)  Base  broader,  thin-walled,  with  oblique,  mesh-like  ridges  or  spiral  swellings, 
which  often  extend  to  a  considerable  distance.  Points  very  thin-walled,  gradually 
tapering,  not  ended  sharply;  frequently  containing  a  reddish  brown  homogeneous 
granular  substance;  fiber  not  very  stiff,  usually  notched.  Base  contains  no  marrow. 
Vegetable  down  from  Eriodendron  anfractuosum . 

(b)  Quite  similar,  but  the  ends  are  not  so  tapering;  without  marrow;  whole  fiber 
somewhat  rough-walled.     Vegetable  doivnfrom  Bombax  heptaphyllum. 

(c)  Very  similar  to  (a),  but  walls  of  fiber  are  quite  roughened  and  contain  at 
intervals  throughout  its  length  a  granular  marrow;  base  thick-walled,  mesh-like  fibrous 
ridges,  but  neither  spirally  developed  nor  very  broad — at  most  only  one-sixth  of  the 

width    of   the    fiber;    ends,    as    before,    thick- walled. 
Vegetable  doion,  Ceiba  cotton,  from  Bombax  ceiba. 

(Fig.  386) 
15.  (a)  Raw  fiber,  brown,  rough-walled;  walls,  1  to  7 
microns  thick;  not  indented;  points  without  marrow; 
stiff  and  very  sharp  at  end;  base  not  broadened,  often 
contains  granular  matter.     Vegetable  down  from  Ochro- 

ma  lagopus (Fig.  387) 

(6)  Raw  fiber,  yellowish,  thin-walled,  walls  very 
uneven  in  thickness;  frequently  weakly  developed 
longitudinal  ridges;  just  at  the  base  the  wall  is  very 
thick.     Vegetable  down  from  Cochlospermum  gassy pium. 


II.    GENERAL  TABLE  FOR  THE  DETERMINA- 
TION OF  THE  VEGETABLE  FIBERS 

Including  cotton,  as  well  as  the  more  important 
fibers  derived  from  bast  or  sclerenchymous  tissues. 

A.  Fibers  Colored  Blue,  Violet,  or  Greenish  with 
Iodine  and  Sulfuric  Acid. 

(a)  Bast  fibers  and  cotton.  (Cotton,  flax,  hemp, 
sunn  hemp,  ramie,  Roa  fiber.) 

I.  The  cross-sections  become  blue  or  violet  with 
iodine  and  sulfuric  acid;  show  no  yellowish  median 
layer;  the  lumen  is  often  filled  with  a  yellowish 
marrow. 

Fig.    387. — Ochroma    lagopus.  1.  Cross-sections:     they   occur   either   singly  or   in 

(X340.)  (Hohnel.)  m.  Mid-  small  groups;  the  single  sections  do  not  join  over  one 
die  part  of  fiber;  b,  base;  another;  are  polygonal,  and  have  sharp  edges;  iodine 
s,  pointed  end;  I,  lumen;  q,  and  sulfuric  acid  colors  them  blue  or  violet ;  they  show 
cross-section;  w,  ceU-wall.        closely  packed,  delicate  layers;   the  lumen  appears  as 

a  yellow  point. 
Longitudinal  appearance:  with  iodine  and  sulfuric  acid,  quite  blue;  it  appears 
transparent,  quite  uniformly  thick;  smooth  or  delicately  marked;  joints  frequent; 
indications  of  dark  lines  running  through,  which  are  usually  crossed;  enlargements  on 
the  fiber,  especially  at  the  joints,  frequent;  the  lumen  appears  as  a  narrow  yellow 
line;   the  natural  ends  of  the  fibers  are  sharply  pointed;  length  4  to  66  mm.,  thickness 

15  to  37  microns Ldnen  or  Flax  (Fig.  388) 

2.  Cross-sections  single  or  very  few  in  a  group,  loosely  held  together;   polygonal  or 
irregular,  mostly  flat,  very  large;   colored  blue  or  violet  with  iodine  and  sulfuric  acid; 


MICRO-ANALYTICAL   TABLES   FOR  VEGETABLE   FIBERS         889 


Fig.  388. — Raw  Linen  Treated  with  Iodine  and  Sulfuric 
Acid.     (Solaro.) 


stratification  not  noticeable;  the  lumen  is  large  and  irregular;  frequently  filled  with  a 
dark  yellow  marrow;  radial 
fissures  frequently  apparent. 
Longitudinal  appearance: 
many  of  the  fibers  remark- 
ably broad;  the  width  of  a 
single  fiber  very  uneven; 
smooth  or  striped;  very 
often  ruptures  in  the  wall; 
with  iodine  and  sulfuric  acid, 
blue  or  violet;  the  lumen 
readily  seen;  very  broad, 
often  containing  a  dark  yel- 
low marrow;  joints  notice- 
able; dark,  transverse  lines 
frequent,  often  crossing  each 
other;  the  ends  are  rela- 
tively thick-walled  and  blunt; 
length  60  to  250  mm.,  thick- 
ness up  to  80  microns. 

China  grass,  Ramie 

3.  Cross-section:  not  many 

in    the    groups;    polygonal; 

mostly     with     straight     or 

slightly    curved    sides     and 

blunt  angles;    the  lumen    is   contracted    lengthwise    regularly;    frequently  contains  a 
yellow  marrow,  many  sections  are  surrounded  by  a  thin,  greenish  colored  layer;  not 

closely  joined    to    one    an- 
other.    The    sections    often 
show    very   beautiful  radial 
marks   or  fissures  and  con- 
centric  layers;     the  various 
layers  are  colored  differently. 
Longitudinal  appearance, 
as  with   Chma  grass;    pro- 
portional dimensions  similar. 
Roa  fiber 
4.  Cross-sections     always 
isolated,     rounded,    various 
shapes,    mostly    kidney- 
shaped;     with     iodine     and 
sulfuric  acid,  blue  or  violet; 
lumen     contracted,     line- 
shaped,   often    containing  a 
yellowish  marrow;  no  strati- 
,  fication. 

Longitudinal  appearance: 
fibers  always  separate;  with 
Fig.  389. — Raw  Ramie  Fiber.     (Solaro.)  iodine   and   sulfuric   acid,  a 

fine     l)lue;       streaked     and 
twisted;    lumen    broad,    distinct,  frequently  contains   yellowish    marrow;   ends   blunt; 


890 


GENERAL   ANALYSIS   OF   THE   TEXTILE   FIBEHS 


the  entire  fiber  not  soluble  in  concentrated  sulfuric  acid;   coated  with  a  very  thin  cuti- 
cle;  length   10   to   GO  mm.,   breadth   12   to  42   microps. 

Cotton,  Caravonica  cotton  (Fig.  390) 
II.  Cross-section  blue  or  violet  with  iodine  and  sulfuric  acid;   polyhedral,  rounded 

or  irregular;  always  sur- 
rounded by  a  yellow  median 
layer. 

1 .  Cross-sections  always 
in  groujjs,  with  angles  more 
or  less  rounded  off,  lying 
very  close  to  one  another; 
all  of  them  surrounded  by 
a  thin,  yellowish  median 
layer;  the  lumen  is  line- 
shaped,  single  or  forked, 
often  broad,  with  inturning 
edges,  without  marrow;  good 
concentric  stratification ;  the 
different  strata  being  differ- 
ently colored. 

Longitudinal  appearance: 
with  iodine  and  sulfuric  acid, 
blue,  greenish,  or  dirty 
yellow;  fibers  irregular  in 
thickness,  frequently  with 
appended  portions  of  yel- 
lowish median  layer;    joints 

and  transverse  lines  frecjiient;    stripes  very  distinct;    tlie  lumen  is  not  very  apparent, 

but  broader   than   linen;   ends   are  broad,  thick-walled,   and   blunt,   often    branched; 

length  5  to  55  mm.,  breadth  10  to  50  microns Hemp  (Fig.  391) 

2.  Cross-sections  in  large  groups,  lying  very  close  together  and  touching;    very 

similar  to  those  of  hemp;    often  crescent-shaped.     Polygonal  or  oval,  with  lumen  of 

varying  size,  frequently  containing  yellowish 

marrow;    lumen  usually  not  line-shaped,  but 

irregular;     a     broad    yellow     median     layer 

always   present,  from  which   the   blue   inner 

strata  are  easily  distinguished;   stratification 

very  distinct,  as  with  hemp. 

Longitudinal    appearance,  as    with  hemp, 

except    in    dimensions,    which    are:     length 

4  to  12  mm.,  breadth  25  to  50  microns. 

<Sunn  hemp  (Fig.  392) 
{b)  Leaf  fibers.     (With  vascular  tissue; 

without    jointed    structure.      Esparto    and 

pineapple  fiber.) 

1.  Cross-sections  in  large,  compact,  often 

crescent-shaped    groups;     very   small;     pale 

blue  or  violet  with  iodine  and  sulfuric  acid;   surrounded  by  a  thick,  shell-like  network 

of  median  layer;   rounded  or  polygonal;    lumen  like  a  point  or  streak;    thick  cuttings 

appear  greenish  or  even  yellow;    frequently  bundles  of  vascular  tissue  with  one  or 

two  rows  of  thick,  yellow-colored  fibers. 


Fig.  390. — Caravonica  Cotton;  Wool-like  Type.  (Solaro.) 


Fig.  391.— Hemp.  ( X 170.)  b,  Ends  of 
fibers;  c,  cross-section;  d,  longitudinal 
view.      (Hohnel.) 


MICRO-ANALYTICAL  TABLES  FOR  VEGETABLE  FIBERS 


891 


Fibers    slender,    regular,    very    thick-walled,    smooth; 


Longitudinal  appearance: 
lumen  often  invisible,  gener- 
ally as  a  fine  line;  ends  are 
tapered  with  needle-like 
points;  color  with  iodine  and 
sulfuric  acid,  blue,  but  often 
quite  faint;  frequently  pres- 
ent short,  thick,  stiff,  com- 
pletely lignified  fibers  from 
vascular  tissue;  length  5 
mm.,   breadth  6  microns. 

Pineapple  fiber 
2.  Cross-sectioiis  in  groups; 
with  iodine  and  sulfuric  acid, 
mostly  blue,  though  also 
yellow;  often  with  pro- 
nounced stratification;  the 
outer  strata  frequently  yel- 
low, while  the  inner  are  blue; 
rounded  or  oval,  seldom 
straight-sided;  lumen  like  a 
point. 

Longitudinal  appearance: 
the  fibers  are  short;  blue 
with  iodine  and  sulfuric  acid;  thin,  very  firm,  smooth,  uniform    in  breadth;    lumen 

yellow ,  Ime-shaped;     ends    are    seldon   pointed, 
mostly  blunt   or   chiselled  off,  or   forked;    length 

1.5  mm.,  breadth  12  microns Esparto 

B.  Fibers  Colored  Yellow  with  Iodine  and 
Sulfuric  Acid. 

(a)  Dicotyledonous  fibers.  (Without  vas- 
cular bundles;  lumen  showing  remarkable  con- 
tractions. Including  jute,  Abelmoschus,  Gambo 
hemp,  Urena,  and  Manila  hemp;  the  latter  some- 
times shows  vascular  tissue.) 

I.  Cross-sections  in  groups;  polygonal  and 
straight-lined,  with  sharp  angles;  lumen  round 
or  oval,  smooth,  and  without  marrow,  cross- 
sections  with  narrow  median  layers  showing  the 
same  color  as  the  inner  strata  with  iodine  and 
sulfuric  acid;  lengthwise  appearance  shows  the 
lumen  with  contractions. 

1.  Cross-sections  polygonal,  straight-lined;  lu- 
men, in  general,  large,  round,  or  oval. 

Longitudinal  appearance:   fibers   smooth,  with- 
-Pseudo-jute  (f7re7ia.siH«-   out  joints    or    stripes;    lumen    distinctly    visible; 


Fig.  392.— Sunn  Hemp.     (Solaro.) 


ala).  (X340.)  (Hohnel.)  I, 
Longitudinal  view;  v,  interrup- 
tion of  lumen;  e,  end  with  thick 
wall;  q,  cross-section;  m,  median 
layer;  L,  small  lumen. 


broad;  with  contractions;  the  ends  always  blunt 
and  moderately  thick;  ends  have  wide  lumen; 
length  1.5  to  5  mm.,  breadth  20  to  25  microns. 

Jute 
2.  Cross-sections    in   general  somewhat  smaller 


892 


GENERAL   ANALYSIS   OF   THE   TEXTILE    FIBERS 


than  jute;   sides  straight,  with  sharp  angles;   kimen  frequently  like  a  point  or  line, 
oval,  occasionally  pomted;   not  so  large  as  with  jute. 

Longitudinal  appearance:  fibers  quite  even  in  thickness,  smooth,  with  occasional 
joints  or  stripes;  lumen  narrow,  irregular  in  thickness,  contractions  frequent;  the  ends 
are  broad,  blunt,  frequently  thickened;   length  1  to  1.6  fnm.,  breadth  S  to  20  microns. 

Pseudo-jute  or  Musk  mallow  of  Abclnioschus 

II.  Cross-sections  in  groups,  lying  close  together;    polygonal,  with  sharp  lines  and 

sharp  or  rounded  angles;    lumen  without  marrow;    the  median  layer  is  broad,  and 

with  iodine  and  sulfuric  acid  is  colored  perceptibly  darker  than  the  inner  layer  of 

cell-wall;  the  lumen  in  places  is  completely  lacking. 

L  Cross-sections  more  or  less  polygonal,  with  sharp  or  sHghtly  rounded  angles;  the 
lumen  is  small,  becoming  broader  and  more  oval  as  the  section  is  more  rounded;   the 

median  layer  is  broad,  and  is 
colored  considerably  darker 
than  the  cell-wall  with  iodine 
and  sulfuric  acid;  stratifica- 
tion occasional  and  indis- 
tinct. 

Longitudinal  appearance: 
the  fibers  vary  much  in  thick- 
ness; lumen  generally  nar- 
row, with  decided  contrac- 
tions, and  in  some  parts 
totally  absent;  the  broader 
fibers  often  striped ;  ends  are 
blunt  and  generally  thick- 
ened; length  2  to  6  mm., 
breadth  14  to  33  microns. 

Gamho  hemp 
2.  Cross-sections  always 
in  groups;  small,  polygonal, 
with  sharp  angles;  lumen 
very  small,  appearing  as  a 
point  or  a  short  line. 

Longitudinal   appearance: 
occasionally     jointed     or 
striped;   lumen   with   decided  contractions,  in  some    places  altogether  lacking;    ends 
blunt  and  sometimes  thickened;  length  1.1  to  3.2  mm.,  breadth  9  to  24  microns. 

Pseudo-jute  from  Urerui  sinnata  (Fig.  393) 

(6)  MoNOCOTYLEDONOUs  FIBERS.     (Occurring  as  vascular  bundles  together  with 

bast;    the  lumen  exhibits  no  contractions;    in  Manila  hemp  vascular  bundles  often 

lacking.     Includes  New  Zealand  flax,  Manila  hemp,  Sansevieria  or  bowstring  hemp,  Pita 

hemp,  and  Yucca  fiber.) 

I.  Cross-sections  generally  roimded,  occasionally  polygonal;  the  hunen  is  always 
rounded,  without  contractions  longitudinally;  median  layer  indistinct,  or  only  as  a 
narrow  line;  vascular  tissue  small  in  amount,  or  altogether  lacking. 

1.  Cross-sections  small,  generally  rounded,  lying  loosely  separated;  very  rounded 
angles;  lumen  small,  round,  or  oval,  without  marrow. 

Longitudinal  appearance:  the  fibers  are  stiff  and  thin;  the  lumen  is  small  but  very 
distinct,  and  uniform  in  width;  the  ends  are  pointed;  no  markings  and  no  joints; 
length  5  to  15  mm.,  breadth  10  to  20  microns New  Zealand  flax  (Fig.  394) 


Fig.  394.— Raw  Fibers  of  New  Zealand  Flax.     (Solaro.) 


MICRO-ANALYTICAL  TABLES   FOR   VEGETABLE  FIBERS 


893 


2.  Cross-sectio7is  polygonal,  with  rounded  angles,  in  loosely  adherent  groups; 
lumen  large  and  round,  often  containing  yellow  marrow. 

Longitudinal  appearance:  fibers  uniform  in  diameter;  walls  thinner  than  those  of 
New  Zealand  flax;  lumen  large  and  distinct;  ends  pointed  or  slightly  rounded;  silicious 
stegmata  adhering  to  the  fiber  bundles  and  to  be  found  in  the  ash  as  bead-likg  strings, 
insoluble  in  hydrochloric  acid;  length  3  to  12  mm.,  diameter  16  to  32  microns. 

Manila  hemp  (Fig.  395) 

II.  Cross-sections  polygonal;  lumen  large  and  polygonal,  with  angles  quite  sharp; 
median  layer  lacking  or  only  in  the  form  of  a  thin  line. 

1.  Cross-sections  distinctly  polygonal,  often  with  blunt  angles,  lying  compactly 
together;  lumen  large  and  polygonal,  with  sharp  angles;   no  stratification  in  cell-wall. 

Longitudinal  appearance:   fibers  thin  and  smooth;    lumen  large  and  distinct;    ends 
pointed;  length  1.5  to  6  mm., 
diameter  15  to  26  microns. 

Sansevieria  fiber 

2.  Cross-sections  polygon- 
al, not  many  sections  to  a 
group,  but  lying  compactly 
together ;  angles  slightly 
rounded;  lumen  not  very 
large,  polygonal,  often  hav- 
ing blunt  angles;  besides  the 
bast-fiber  sections  are  to  be 
noticed  some  vascular  bun- 
dles in  the  form  of  large 
spirals. 

Loiigitudinal  appearance: 
fibers  uniform  in  diameter; 
lumen  not  very  large,  but 
uniform;  no  structure;  ends 
pointed  and  sometimes 
blunt;  length  1.3  to  3.7 
mm.,  diameter  15  to  24  mi- 
crons  Aloe  hemp 

3.  Cross-sections  polygon- 
al, with  straight  lines;    angles  sharp,  though  sometimes  blunt;   sections  lie  compactly 
together;   lumen  large  and  polygonal,  though  angles  not  so  sharp. 

Longitudinal  appearance:  fibers  stiff,  and  often  very  wide  toward  the  middle; 
lumen  large;  ends  broad,  thickened,  and  often  forked;  large,  shining  crystals  to  be 
found  in  the  ash,  which  are  derived  from  the  chisel-shaped  crystals  of  calcium  oxalate 
clinging  to  the  outside  of  the  fiber;  these  crystals  are  often  ^  mm.  in  length;  length 
of  fiber  1  to  4  mm.,  diameter  20  to  32  microns Pita  hemp 

III.  Cross-sections  polygonal  and  small,  sides  straight,  with  very  sharp  angles; 
lumen  small,  usually  as  a  point  or  line-shaped;  sections  lie  compactly  together  and 
are  surrounded  by  a  thick,  distinct  median  layer. 

1.  Cross-sections  as  above. 

Longitudinal  appearance:  fibers  very  narrow;  lumen  also  very  narrow;  longi- 
tudinal ridges  frequent;  ends  usually  sharp  pointed;  length  0.5  to  6  mm.,  diameter 
10  to  29  microns Yucca  fiber  ^  (Fig.  396) 

*  This  is  obtained  from  the  Yucca  gloriosa  and  belongs  to  the  finest  kind  of  mono- 
cotyledonous   fibers.     The   fiber   frequently   shows  no   visible   markings;     the   cross- 


Raw  Fibers  of  Manila  Hemp. 


894  GENERAL   ANALYSIS   OF   THE   TEXTILE   FIBERS 


III.   ANALYTICAL  REVIEW   OF   THE   CHIEF   VEGETABLE   FIBERS. 

1.  Those  occurring  as  thick,  fibrous  bundles,  also  with  vascular  tissue  (monocotyle- 
donous  fibers) (see  2) 

Vascular  tissue  absent;  sections  and  fibers  always  single;  round  or  kidney-shaped 
by  being  pressed  together;  fibers  with  a  thin  external  cuticle  insoluble  in  concentrated 
suKuric  acid,  and  not  swelUng  (vegetable  hairs) (see  7) 

Vascular  tissue  absent;  the  fibers  are  bundles  of  bast  filaments;  sections  occur  i  g 
two  or  more  together  (mostly  true  dicotyledonous  fibers) (see  13) 

2.  Lumen  very  narrow,  Hne-shaped,  much  thinner  than  the  wall (see  3) 

Lumen  in  thickest  fibers  almost  as  wide,  or  even  wider,  than  the  wall;   completely 

lignified (see  4) 

3.  Sections  polygonal,  sides  straight,  with  sharp  angles;  completely  lignified; 
diameter  10  to  20  microns Yucca  fiber 


Fig.  396. — Yucca  Fiber.     (X400.)     A,  Longitudinal  view;   B,  cross-section;  m,  median 
layer;  t,  transverse  markings.     (Micrograph  by  author.) 

Sections  rounded  to  polygonal;  often  flattened  or  egg-shaped;  the  inner  strata  at 
least  not  lignified;  diameter  4  to  8  microns Pineapple  fiber 

4.  Thick,  strongly  silicified  stegmata  occurring  at  intervals  on  the  fiber  bundles  in 
short  to  long  rows,  sometimes  but  few;  these  are  four-cornered,  have  serrated  edges, 
and  show  a  round,  bright,  transparent  place  in  the  middle;  they  are  easily  seen  after 
the  fiber  has  been  macerated  with  chromic  acid,  and  are  about  30  microns  in  length; 
in  the  ash  of  fibers  previously  treated  with  nitric  acid,  they  appear  in  the  form  of 
pearly  strings,  often  quite  long,  and  insoluble  in  hydrochloric  acid;  they  are  joined 
together  lengthwise;  the  fibers  are  thick-walled,  with  fissure-like  pores;  3  to  12  mm. 
long;  the  fiber  bundles  are  yellowish  and  lustrous Manila  hemp 

Stegmata  present,  sometimes  in  small,  sometimes  in  large  quantities;  they  are 
lens-shaped,  small  (about  15  microns  wide),  and  are  fastened  to  the  exterior  fibers  of 
the  bundles  by  serrated  edges;  in  the  ash  of  the  fiber  they  melt  together  in  the  form 
of  indistinct  globules;  in  the  ash  of  fibers  previously  boiled  in  nitric  acid  they  appear 
as  yeast-cells,  joined  together  in  round  skeletons  of  silica;  the  fibers  are  often  thin- 
walled,  with  numerous  pores;  1  to  2  mm.  in  length;  the  raw  fibers  generally  brown 
and  rough Coir 

Stegmata  absent,  hence  the  fibers  are  not  accompanied  by  silicified  elements .  (see  5) 

5.  Fiber  bundles  covered  externally  at  intervals  with  crystals  of  calcium  oxalate,  at 

sections  are  small  and  polygonal,  with  straight  sides  and  sharp  points.     The  median 
layer  is  very  noticeable  and  the  whole  fiber  is  strongly  lignified. 


micro-aNalyticaL  tables  for  vegetable  fibers       ^05 

times  up  to  0.5  mm.  in  length;  lustrous,  with  quadrangular  sections,  chisel-shaped  at 
the  ends,  hence  they  appear  as  thick,  needle-shaped  crystals;  when  present  in  large 
numbers  these  crystals  occur  in  long  rows  which  are  frequently  visible  to  the  naked 
eye,  and  always  easily  recognisable  under  the  microscope,  especially  in  the  ash.  The 
fiber-bundles  are  mostly  thick,  and  their  outer  fibers  (as  a  result  of  their  preparation) 
frequently  contain  fissures  or  are  torn;   thickness  of  the  walls  very  uneven;  fibers  often 

much  widened  at  the  middle Pita  hemp 

Without  crystals,  generally  thin;  in  cross-section  usually  less  than  100  fibers  to  a 
bundle;  thickness  of  walls  and  lumen  very  uniform (see  6) 

6.  Sections  mostly  round,  not  very  compact;  lumen  usually  thinner  than  the  wall, 
but  never  a  single  line;   in  section  round  or  oval;  vascular  tissue  in  but  small  amount. 

New  Zealand  flax 

Sections,  on  one  side  at  least,  polygonal;    section  of  lumen  polygonal,  with  angles 

more  or  less  sharp;   generally  as  wide  or  wider  than  the  wall;   vascular  tissue  frequent. 

Aloe  hemp 

7.  Fibers  mostly  rope-shaped,  twisted,  externally  streaked,  generally  possessing  fine 
granules  or  marked  with  little  Imes,  therefore,  rough;  thin  to  thick  walls;  cross-sections 
squeezed  together,  or  round  to  kidney-shaped,  hence  the  fiber  has  more  or  less  the 
shape  of  a  flat  band;  section  of  lumen  more  or  less  arched,  line-shaped,  frequently 
containing  yellow  marrow;  consists  of  pure  cellulose  with  the  exception  of  the  thin 
cuticle Cotton 

Fibers  not  twisted,  smooth  externally,  and  without  longitudinal  markings;  fibers  not 
flat,  sections  round;  walls  generally  very  thin;  sometimes,  however,  they  are  thick; 
lignified,  scarcely  swelling  in  ammoniacal  copper  oxide Vegetable  down 


Vegetable  silks  I 

8.  Fibers  on  the  inside  possess  from  2  to  5  broad  ridges,  which  at  times  are  very 
noticeable,  at  others  scarcely  visible;  they  run  lengthwise  in  the  fiber,  and  in  section 
are  semicircular;  on  this  account  the  walls  appear  unequal  in  thickness  when  viewed 
longitudinally;  the  maximum  thickness  is  about  35  microns Vegetable  silks  (see  9) 

Fibers  without  ridges;  maximum  thickness  mostly  30  to  35  microns. 

Vegetable  doum  (see  12) 

9.  Largest  diameters  50  to  60  microns;  length  3.5  to  4.5  cm (see  10) 

Largest  diameters  35  to  45  microns;  length  1.5  to  4  cm (see  11) 

10.  Fibers  contracted  at  the  lower  end,  and  directly  above  abruptly  swelling, 
becoming  80  microns  thick;  the  under  portion  of  the  swollen  area  contains  numerous 
pore-canals;  fibers  feather-like  or  brush-like  arising  from  a  straight  shaft. 

Vegetable  silk  from  Senegal 
Contrary  to  the  above  the  fibers  originate  from  one  point,  like  a  fan;   remarkably 

strong,  curved  backward;  very  firm Vegetable  silk  from  India 

Like  the  foregoing,  but  the  fiber  is  stiff,  straight,  weak,  and  brittle. 

Calotropis  procera 

11.  Thickened  ridges  very  noticeable;  in  the  cross-sections  often  occurring  in  the 
form  of  a  semicircle;   bound  together  in  a  strictly  reticulated  manner. 

Vegetable  silk  from  Asclepias  cornuti 
Thickened  ridges  indistinct,  projecting  but  slightly  in  the  cross-section. 

Vegetable  silk  from  Asclepias  curassavica 

12.  Raw  fiber,  yeUowish;  broadened  at  the  lower  end  (up  to  50  microns);  also 
recticular  thickening  or  transverse  markings;  wall  1  to  2  microns  thick.  .Bombax  cotton 

Raw  fiber  brown;  the  lower  end  contracted  and  not  showing  reticulated  thickenings; 
fiber  almost  altogether  thin-walled,  though  just  at  the  lower  end  very  thick-walled. 

Cochlospermum  gossypium 


896 


GENERAL   ANALYSIS   OF   THE   TEXTILE   FIBERS 


I 


13.  Thick  fiber  bundles,  whose  outer  surface  contains  at  intervals  series  of  thick 
silicious  plates,  having  sharp  indented  edges  and  a  round  hollow  space. 

Manila  hemp  (see  under  4) 
Silicious   plates   absent;     lengthwise   the    lumen   often    exhibits   remarkable   con- 
tractions, while  the  wall  is  very  uneven  in  thickness;    at  intervals,  indeed  the  lumen 
is  almost  entirely  interrupted;  joints  and  transverse  fissures  along  the  fiber;  transverse 
markings  and  lines,  which  appear    somewhat    like    zones  or  knots,  are  completely 

lacking,  or  are  very  rare  and  indis- 
tinct; completely  lignified,  hence 
colored  yellow  with  iodine  and  sul- 
furic acid (see  14) 

Silicious  plates  absent,  also  re- 
markable contractions  of  the  lumen; 
thickness  of  the  walls  very  uniform; 
joints  and  fissures  along  the  fiber, 
transverse  lines  and  markings  fre- 
quent, hence  the  fiber  often  appears 
as  if  it  contains  swollen  knots;  un- 
lignified,  or  only  lignified  on  the 
external  layer  of  membrane,  hence 
lengthwise  the  fiber  is  colored  blue 
with  iodine  and  sulfuric  acid  or  violet 
or  green,  or  at  the  most  colored  yel- 
low in  places (see  17) 

14.  Exterior  layers  of  membrane 
narrow  and  showing  the  same  colora- 
tion with  iodine  and  sulfuric  acid  as 
the  inner  layers,  hence  the  same  as 
the  entire  cross-section  the  lumen 
hardly  ever  completely  interrupted. 

(see  15) 
Median   layer   in    sections    wide; 
colored     considerably     darker    with 
Fig.  397.— il 6eZmosc/iMS  Jute.     (X325.)     (Hohn-   iodine  and  sulfuric  acid;  lumen  often 

el.)     /,  Longitudinal    view;    q,    cross-section;    completely  interrupted (see  16) 

e,    ends;    L,    small    lumen;    v,    narrowing  of         15.  Lumen      in      general     large, 
lumen;  m,  median  layer.  diameter   as   wide   or   only   a    Httle 

narrower    than    the   wall;  in  section 

round  or  oval,  seldom  as  a  point;  no  crystals  of  calcium  oxalate True  jute 

Lumen  usually  small,   diameter  much  narrower  than  the  thick  wall  in  section 
frequently  as  a  point;   crystals  of  calcium  oxalate  of  frequent  occurrence  (detected  by' 
ignition) Pseudo-jute  (Abelmoschus)  (Fig.  397) 

16.  Lumen  almost  always  considerably  smaller  than  the  wall;  ends  usually  very 
thick-walled  and  narrow;  calcium  oxalate  crystals  of  frequent  occurrence. 

Pseudo-jute  (Urena  sinuata) 

Lumen  frequently  as  wide  as  or  wider  than  the  wall,  mostly  narrower  however; 

ends  broad  and  blunt Gambo  hemp 

17.  The  lumen  in  the  middle  portion  of  the  fiber  generally  line-shaped,  much 
narrower  than  the  wall;  ends  never  blunt,  always  sharply  pointed;  sections  isolated 
or  in  small  groups,  regular  in  diameter,  sharp-angled  and  straight-sided  polygonals; 
without  separate  median    layer;    iodine  and  sulfuric  acid  colors  the  entire   section 


REACTIONS   OF   BAST   FIBERS  897 

blue  or  violet;  the  lumen  in  the  cross-section  is  very  small,  or  as  a  point,  containing  a 

marrow  which  is  colored  yellow  with  iodine  and  sulfuric  acid, Linen  or  Flax 

Lumen,  at  least  in  the  central  portion  of  the  fiber,  always  much  thicker  than  the 
walls;  in  section  generally  more  or  less  flattened,  narrow  to  broad,  egg-shaped  or 
oval.  Fiber  ends  blunt,  never  sharply  pointed;  sections  almost  never  sharp-angled 
polygonals,  but  more  or  less  oval  or  elliptical,  and  with  a  rounded  boundary ....  (see  IS) 

18.  Breadth  of  fiber  up  to  80  microns;  maximum  length  15  to  60  mm.;  sections 
always  in  compact  groups,  which  often  consist  of  many  fibers,  with  thinner  or  thicker 
layers  of  membrane,  which  are  colored  yellow  with  iodine  and  sulfuric  acid,  hence 
the  fiber  is  never  colored  a  pure  blue,  but  dirty  blue  to  greenish,  and  in  places  yellow; 
ends  often  have  side  branches  projecting (see  19) 

19.  Lignified  exterior  membranes  very  thin;  lumen  in  section  narrow,  very  seldom 
broad,  fissure-like  or  line-shaped,  often  branched,  without  marrow Hemp 

Lignified  exterior  layers  often  as  wide  as  the  interior  layers,  or  wider;  the  interior 
layers  are  often  loosened  in  places  from  the  exterior  ones  where  they  are  thin;  lumen 
in  section  scarcely  ever  narrow  or  fissure-shaped,  but  broad,  oval,  or  long;  often  con- 
taining a  yellowish  marrow Sunn  hemp 

10.  Reactions  of  Bast  Fibers. — In  Table  VI,  by  Goodale,  are  presented 
reactions  for  the  principal  bast  fibers. 

11.  Microscopical  Comparison  of  Various  Fibers. — Zetzsche,  in  Table 
VII,  gives  comparisons  between  the  principal  fibers  as  obtained  by  a 
microscopical  examination. 

12.  Systematic  Analysis  of  Mixed  Fibers. — Table  VIII,  by  Pinchon, 
represents  an  attempt  to  give  a  systematic  qualitative  analysis  of  the  most 
important  textile  fibers. 

The  fiber  is  first  treated  with  a  10  percent  solution  of  caustic  potash, 
which  causes  any  animal  fiber  to  dissolve,  the  vegetable  fibers  remaining 
insoluble.  If  lead  acetate  solution  be  added  to  the  fiber  after  treatment 
with  caustic  potash,  and  wool  is  present  it  will  become  dark,  owing  to  the 
formation  of  lead  sulfide  from  the  sulfur  existing  in  the  wool.  If  silk  be 
suspected,  warm  in  concentrated  sulfuric  acid,  which  will  cause  the  silk 
to  darken  rapidly  and  the  wool  more  slowly. 

With  a  due  degree  of  caution,  this  schematic  analysis  may  be  employed 
with  considerable  success,  though  confirmatory  tests  should  be  applied 
to  the  detection  of  each  fiber  indicated.  The  differentiation  between  the 
various  vegetable  fibers  given  is  especially  difficult.  Too  much  reliance, 
therefore,  must  not  be  placed  on  the  accuracy  of  analysis  depending  on 
observations  based  on  the  reactions  and  measurements  of  these  tables, 
unless  backed  up  by  expert  judgment  resulting  from  long  experience  in 
fiber  analysis  and  microscopy.  Particularly  in  the  case  of  the  vegetable 
bast  and  leaf  fibers  the  samples  will  be  found  to  be  quite  heterogeneous 
in  their  reactions,  and  would  often  be  confused  with  mixtures  of  different 
fibers,  when  in  reality  they  may  be  quite  simple  in  their  origin.  The 
microscopist  must  be  sufficiently  experienced  to  give  their  proper  values 
to  the  observations  recorded^  especially  with  regard  to  the  mierochemical 
reactions. 


898 


GENERAL   ANALYSLS   OF   THE   TEXTILE   FIBERS 


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REACTIONS  OF  VEGETABLE  FIBERS  WITH  lODINE-SULFURIC  ACID     903 

13.  Reactions  of  Vegetable  Fibers  with  lodine-Sulfuric  Acid  Reagent. 

— All  fibers  of  vegetable  origin  have  an  internal  canal  or  cavity  (lumen), 
and  when  this  is  observed  under  the  microscope  in  connection  with  the 
color  reactions  obtained  by  treatment  of  the  fiber  with  the  iodine-sulfuric 
acid  reagent  certain  characteristics  may  be  noted  as  summarised  in  the 
following  table: 

(A)  Gives  blue  color: 
(a)  Isolated  fibers: 

(1)  Wide  canal — cotton, 

(2)  Narrow  canal,  often  interrupted  and  discontinuous — mercerised  cotton ; 
(fe)  Filaments  devoid  of  vesicles  or  spiral  tubes,  with  fibers  surrounded  by  incrust- 

ing  strata,  and  attached  in  bundles  if  raw,  and  easily  separated  if 
bleached : 

(1)  Narrow  canal — Linen,  mulberry,  broom, 

(2)  Wide  canal — Hemp,  ramie,  sunn  hemp,  calotropis. 

(B)  Gives  some  blue  and  some  yellow : 

(o)  Filaments  often  having  on  their  surface  vesicles  or  spiral  tubes,  if  raw,  with 
fibers  surrounded  by  incrusting  substances  and  attached  in  bundles: 
(1)  Narrow  canal — Pineapple,  papyrifera,  kazinoki,  stipa,  esparto. 

(C)  Gives  yellow  color: 
(a)  Isolated  fibers: 

(1)  Very  wide  canal — Vegetable  silks; 
(6)  Filaments  often  having  on  the  surface,  if  raw,  vesicles  or  spiral  tubes,  rarely  if 
bleached:  fibers  generally  closely  attached  to  each  other: 

(1)  Narrow  canal  thinner  than  fiber  wall — Yucca,  raphia,  Panama,  palm.  New 

Zealand  flax, 

(2)  Wide  canal  or  wider  than  fiber  wall — Manila  hemp,  cocoanut,  agave,  sisal, 

sansevieria,  aloe; 
(c)   Filaments  devoid  of  vesicles  or  spiral  tubes,  with  fibers  attached  to  or  sur- 
rounded by  incrusting  substances: 

(1)  Wide  canal — Edgeworthia  papyrifera,  broussonetia  (mulberry), 

(2)  Narrow  canal — Jute,  mallow. 

The   fibercross-sections    when  treated  with  the  iodine,  sulfuric  acid 
reagent  give  the  following  reactions* 

(A)  Gives  blue  color: 

(a)  Outline  curvilinear: 

(1)  Section  elongated  and  borders  sinuous: 

(a)  Sections  isolated — Cotton,  mulberry,  bleached  ramie, 

(b)  Sections  attached — Raw  ramie,  linen  waste,  raw  hemp,  simn  hemp, 

calotropis, 

(2)  Section  rounded  or  slightly  oval: 

(a)  Sections  isolated — Mercerised  cotton, 

(b)  Sections  attached — Calotropis; 
(6)  Outline  polygonal : 

(1)  Section  elongated  and  attached: 

(a)  Sides  and  angles  slightly  curved — Linen  waste,  raw  hemp, 

(b)  Sides  straight  and  angles  sharp — Broom, 


904  GENERAL   ANALYSIS   OF   THE   TEXTILE   FIBERS 

(2)  Section  rounded: 

(a)  Sections  isolated — Bleached  linen, 

(6)  Sections  attached — Hemp  waste,  raw  flax. 

(B)  Gives  blue  to  yellow  colors: 
(a)  Outline  curvilinear: 

(1)  Section  elongated  and  isolated — Broussonetia,  kazinoki, 
(6)  Outline  polygonal: 

(1)  Section  rounded  and  attached — Pineapple,  stipa,  esparto 

(C)  Gives  yellow  color: 

(a)  Outline  curvilinear: 

(1)  Section  rounded  or  slightly  oval: 

(a)  Sections  isolated — Vegetable  silks, 

(6)  Sections  close  together  but  not  attached — New  Zealand  flax,  Edge- 
worthia  papyrifera, 

(2)  Section  elongated,  sides  sinuous,  often  isolated,  large  lumen — Broussonetia; 

(b)  Outline  polygonal: 

(1)  Section  rounded: 

(a)  Close  together  but  not  attached,  large  lumen — Manila  hemp, 

(b)  Sections  attached,  small  lumen — Raphia,  palm, 

(2)  Section  quadrangular  and  attached — Agave,  sansevieria,  cocoanut, 

(3)  Section  with  straight  sides  and  acute  angles: 

(a)  Sections  attached,  wide  lumen — Sisal,  aloe, 

(b)  Sections  attached  but  lumen  small — Yucca,  jute,  mallow. 


CHAPTER  XXVI 
ANALYSIS  OF  TEXTILE  FABRICS  AND   YARNS 

1.  Wool  and  Cotton  Fabrics. — In  the  analysis  of  finished  textile  fabrics 

it  must  be  remembered  that  besides  the  fibers  there  is  nearly  always  present 
also  a  certain  amount  of  sizing  and  finishing  materials,  mordants  and 
coloring  matters,  and  these  must  be  taken  account  of  in  the  analysis  of 
the  fabric.  The  finishing  materials  and  coloring  matter  should  be  removed 
as  far  as  possible  by  boiling  a  weighed  sample  of  the  fabric,  first  in  a 
1  percent  solution  of  hydrochloric  acid,  then  in  a  dilute  solution  of  sodium 
carbonate  (about  a  ^  percent  solution),  and  finally  in  water.  It  is  then 
air-dried  and  re  weighed;  the  loss  will  represent  finishing  materials.  A 
portion  of  the  material  is  then  dried  at  100°  C,  for  an  hour  (or  until 
constant  weight  is  obtained)  and  weighed;  this  weight  will  represent  the 
actual  amount  of  true  fiber  present  in  the  sample,  and  the  loss  will  corre- 
spond to  moisture.  Then  steep  for  twelve  hom's  in  a  mixture  of  equal 
parts  of  suKuric  acid  and  water,  and  mix  with  three  volimies  of  alcohol 
and  water;  filter  off  the  dissolved  cotton  and  wash  the  residue  of  wool 
well  with  alcohol.  Dry  at  100°  C,  and  weigh;  this  will  give  approximately 
the  amount  of  wool  present.  By  this  treatment  the  wool  suffers  a  loss  of 
about  2^  percent.     The  following  example  will  illustrate  this  method: 

Grams. 

Sample  weighed 3 .  62 

After  treatment  with  acid  and  alkah 3 .  17 

Finishing  materials,  etc 0 .  45 

After  dr\'ing  at  100°  C 2.77 

Loss  as  water 0 .  40 

Wool  left  after  treating  with  acid 1 .  96 

Cotton,  by  difference 0 .  81 

905 


906  ANALYSIS   OF  TEXTILE   FABRICS   AND   YARNS 

Hence  the  composition  of  this  sample  would  be  as  follows: 

Percent 

Finishing  materials 12 .  43 

Moisture 11.05 

Wool 54 .  14 

Cotton 22.38 


100.00 


Another,  and  perhaps  a  better,  method  for  determining  the  relative 
amounts  of  wool  and  cotton  in  a  mixed  fabric  or  yarn,  especially  when  the 
cotton  is  present  in  rather  large  proportion,  is  to  remove  the  wool  by 
treatment  with  a  dilute  boiling  solution  of  caustic  potash.  The  estimation 
is  carried  out  in  the  following  manner: 

The  sample  to  be  tested  is  treated  with  hydrochloric  acid  and  sodium 
carbonate  solutions  as  before,  in  order  to  remove  finishing  materials,  and 
after  thorough  washing  is  dried  at  100°  C.  and  weighed.  This  gives  the 
weight  of  the  dry  fibers.  The  weighed  sample  is  then  boiled  for  twenty 
minutes  in  a  5  percent  solution  of  caustic  potash.  It  is  not  advisable  to 
use  caustic  soda  instead  of  caustic  potash,  as  the  results  obtained  are  not 
quite  as  satisfactory.  The  residue  is  well  washed  in  fresh  water,  and  redried 
at  100°  C.  and  weighed.  The  residue  consists  of  cotton,  the  wool  having 
been  dissolved  by  the  caustic  potash.  If  the  residue  becomes  disintegrated 
and  cannot  be  washed  and  dried  as  one  piece,  it  should  be  collected  on  a 
tared  filter  (one  which  has  been  dried  at  100°  C.  and  weighed)  and  well  washed 
with  water,  then  dried  at  100°  C,  and  weighed.  The  tared  weight  of  the  filter 
subtracted  from  the  latter  will  give  the  weight  of  the  cotton  particles. 

In  case  yarns  are  to  be  analysed,  the  preliminary  treatment  should 
consist  of  a  thorough  scouring  with  soap.  After  drying  in  the  air,  the  loss 
in  weight  should  be  recorded  as  grease  and  miscellaneous  dirt.  On  then 
drying  at  100°  C.  to  constant  weight,  the  loss  will  represent  moisture,  and  the 
residue  dry  fiber.     This  is  then  analysed  as  in  the  manner  above  described. 

Examples : 

(a)  Analysis  of  a  cloth  sample:  q^.  ^ 

Weight  of  sample 5 .  42 

After  treatment  with  acid  and  alkali 5.10 

Finishing  materials,  etc 0. 32 

After  drying  at  100°  C 4.26 

Loss  as  water 0 .  84 

Cotton  left  after  boiling  with  caustic  alkali 2 .  82 

Wool,  by  difference 1 .  44 


WOOL  AND  COTTON  FABRICS  907 

Hence  the  composition  of  this  sample  would  be: 

Percent. 

Finishing  materials 5 .  98 

Moisture 15 .  50 

Cotton 52.03 

Wool 26.49 


100.00 


Since  the  cotton  itself  suffers  a  slight  loss  on  boiling  with  caustic  potash, 
it  is  customary,  as  a  correction,  to  add  to  the  cotton  found  3  percent  of  its 
weight,^  and  to  subtract  a  corresponding  amount  from  that  of  the  wool. 
On  applying  this  correction  the  result  of  the  above  analysis  would  become : 

Percent. 

Finishing  materials 5 .98 

Moisture 15 .  50 

Cotton 53 .  59 

Wool 24.93 


100.00 


Figured  on  the  weight  of  the  dry  fiber,  the  relative  amounts  of  the  two 
fibers  in  the  above  samples  would  be: 

Percent. 

Cotton 68.2 

Wool 31.8 

100.0 

Since,  however,  in  making  mixes,  the  dry  weights  of  the  fibers  are  not 
taken,  we  may  assume  the  weight  to  include  the  normal  amount  of  moisture 
held  by  each  fiber.  As  the  normal  amount  of  moisture  for  cotton  is 
about  8  percent,  and  for  wool  about  16  percent,  we  may  approximate  very 
closely  to  the  true  composition  of  this  sample  by  adding  to  the  dry  weights 
of  the  fibers  their  respective  amounts  of  moisture,  the  relative  amounts 
of  cotton  and  wool  then  become: 

Grams. 

Weight  of  cotton  found 2.82 

Add  3  percent  correction 0 .  08 

2.90 

^  Some  writers  state  that  5  percent  should  be  added  to  the  cotton  but  the  author 
has  found  that  the  cotton  will  not  lose,  as  a  rule,  more  than  3  percent.  The  Condi- 
tioning House  at  Aachen  has  confirmed  his  results  in  this  matter  and  give  3.5  percent 
as  the  figure  for  the  loss  in  the  weight  of  the  cotton. 


908  ANALYSIS   OF   TEXTILE   FABRICS   AND   YARNS 

This  represents  92  percent  of  air-dry  cotton. 

Grams. 
Hence  air-dry  cotton  would  be 3.15 

Weight  of  wool  found 1 .  44 

Subtract  correction  for  cotton 0 .  08 

1.36 
This  represents  84  percent  of  air-dry  wool. 

Grams. 
Hence  air-dry  wool  would  be 1 .  62 

Therefore  the  relative  amounts  of  cotton  and  wool  on  this  basis  would 
be: 

Percent . 

Cotton 66 . 0 

Wool 34 . 0 

(b)  Analysis  of  a  yarn : 

Grams. 

Weight  of  sample 5 .  65 

Scoured  in  soap,  washed  and  air-dried 4 .  97 

Grease,  etc 0 .  68 

Dried  at  100°  C 4.32 

Loss  as  moisture 0 .  65 

Weight  of  filter-paper  dried  at  100°  C 1 .  16 

Weight  of  filter  and  residue  of  cotton  dried  at  100°  C 3 .66 

Weight  of  dry  cotton 2 .  50 

Add  3  percent  correction 2 .  57 

Correct  for  moisture  at  8  percent 2 .  68 

Weight  of  dry  wool  by  difference  (with  correction) 1 .  75 

Correct  for  moisture  at  16  percent 2 .  08 

Hence  the  composition  of  this  yarn  may  be  expressed  as: 

Percent. 

Grease,  etc 12.00 

Moisture 11.50 

Cotton 45 .  40 

Wool 31.10 

100 . 00 


WOOL  AND  COTTON  FABRICS  909 

And  the  relative  proportion  of  the  two  fibers  would  be  as  follows: 

Dry  at  100°  C.       Air-dry. 

Cotton 59.5  56.3 

Wool 40.5  43.7 


100.0 


The  following  scheme  for  the  analysis  of  a  fabric  containing  wool  and 
cotton  is  given  by  Herzfeld:^ 

(a)  Estimation  of  moisture. — Five  grams  of  the  fabric  are  dried  at 
100°  C.  until  the  weight  is  constant.  The  loss  indicates  the  amount  of 
moisture  present. 

(6)  Estimation  of  cotton. — Five  grams  of  the  fabric  are  boiled  for 
one-quarter  hour  with  100  cc.  of  a  0.1  percent  solution  of  caustic  soda, 
then  washed  with  water  and  treated  with  lukewarm  10  percent  caustic 
potash  solution,  until  the  wool  fibers  are  completely  dissolved,  if  necessary 
the  liquid  being  raised  to  the  boiling-point.  The  residue  is  washed  with 
water,  then  treated  for  one-quarter  hour  with  dilute  hydrochloric  acid, 
then  washed  again  with  water,  boiled  for  one-quarter  hour  with  distilled 
water,  washed  with  alcohol  and  ether,  and  finally  dried  at  100°  C.  until 
constant  weight  is  obtained.  The  residue  is  cotton.  The  object  of  wash- 
ing with  dilute  hydrochloric  acid  is  to  neutralise  the  excess  of  caustic 
alkali  in  the  fiber,  so  that  it  may  be  more  readily  removed,  as  caustic  alkali 
remains  in  the  fiber  very  tenaciously. 

(c)  Estimation  of  wool. — Five  grams  of  the  cloth  are  boiled  with  100  cc. 
of  a  dilute  solution  of  soda-ash  for  one-quarter  hour,  washed  with  water, 
and  steeped  for  two  hours  in  sulfuric  acid  of  58°  Be.^  then  washed  with 
water,  and  boiled  for  one-quarter  hour  with  water,  and  finally  washed 
with  alcohol  and  ether,  and  dried  at  100°  C,  until  constant  weight  is 
obtained.     The  residue  is  wool. 

{d)  Dressing  and  dye  are  found  by  difference. 

The  method  of  analysis  given  by  Kapff  ^  is  as  follows :  Weigh  out 
5  grams  of  the  sample  (air-dry),  scour  with  a  luke-warm  (140°  F.)  ammo- 
niacal  solution  of  soap  to  remove  impurities  and  finishing  materials  (in  the 
case  of  heavily  finished  goods  it  may  be  necessary  to  use  also  a  hot  2  percent 
solution  of  hydrochloric  acid),  then  wash  well  and  air-dry  overnight. 
The  difference  in  weight  (diminished  by  2  percent  if  boiled  with  hydro- 
chloric acid,  as  loss  to  the  fiber)  corresponds  to  impurities  and  finish. 
Tlie  sample  is  now  boiled  for  fifteen  minutes  in  a  solution  of  5  grams 

^  Yarns  and  Textile  Fabrics,  p.  145. 

^  Acid  of  this  strength  is  somewhat  too  strong,  as  it  will  decompose  the  wool  to  a 
considerable  extent.  It  is  not  safe  to  employ  sulfuric  acid  of  greater  strength  than 
1  part  of  acid  to  1  part  of  water  by  volume. 

5  Texiil-Zeil.,  1900,  p.  462. 


910  ANALYSIS  OF  TEXTILE   FABRICS   AND   YARNS 

of  caustic  soda  in  250  cc.  of  water  (3°  to  4°  Be.),  which  will  cause  all  the 
wool  to  be  dissolved.  The  residue  of  cotton  is  thrown  on  a  fine  copper 
gauze  and  washed,  first  with  water,  and  then  with  dilute  hydrochloric 
acid  and  finally  with  water  again,  after  which  it  is  allowed  to  dry  in  the 
air  for  twelve  hours  and  reweighed.  To  this  weight  add  3.5  percent  of  its 
amount  as  a  correction  for  loss  to  the  cotton  on  boiling  with  the  alkali, 
and  this  figure  will  then  represent  the  weight  of  cotton  present. 

When  a  rough,  approximate  analysis  of  a  wool-cotton  fabric  is  desired, 
it  will  be  sufficient  only  to  weigh  the  sample,  boil  for  fifteen  minutes  in  a 
5  percent  solution  of  caustic  potash,  wash  well  in  acidulated  water,  then 
in  fresh  water,  and  dry  in  the  air.  On  reweighing,  the  amount  of  cotton 
will  be  ascertained,  while  the  loss  in  weight  will  represent  the  amount  of 
wool.  Results  attained  by  this  process  are  usually  sufficiently  accurate 
to  give  one  a  practical  idea  of  the  approximate  relative  amounts  of  wool 
and  cotton  present  in  a  sample  of  mixed  goods. 

Another  method  for  the  separation  of  wool  from  cotton  in  their  quantita- 
tive estimation  is  treatment  of  the  mixed  fibers  with  an  ammoniacal 
solution  of  copper  oxide,  whereby  the  cotton  is  dissolved ;  and  after  washing 
and  drying,  the  residue  of  wool  is  weighed.  This  method,  however,  is  not 
very  satisfactory,  as  it  is  difficult,  in  the  first  place,  to  obtain  a  complete 
and  thorough  solution  of  the  cotton;  and  in  the  second  place,  the  wool 
will  be  considerably  affected  by  this  treatment  and  more  or  less  decom- 
posed. Consequently  the  results  obtained  by  this  method  are  not  very 
accurate,  and  it  cannot  be  recommended. 

For  the  analysis  of  wool  and  cotton  fabrics  or  yarns  where  the  amount 
of  wool  is  relatively  quite  small,  Heerman  recommends  the  following 
method  in  which  the  wool  is  separated  and  estimated  by  direct  weighing: 
The  method  is  based  on  the  solubility  of  cotton  and  the  insolubility  of  wool 
in  cold  sulfuric  acid  of  a  certain  concentration.  In  a  series  of  experiments 
it  was  found  that  an  acid  containing  80  percent  of  H2SO4  is  the  most 
suitable  for  the  purpose.  Sulfuric  acid  of  this  strength  dissolves  cotton 
completely  in  from  two  to  three  hours.  Pure  wool  treated  for  six  hours 
with  80  percent  sulfuric  acid  lost  only  1.5  percent  in  weight,  and  was  micro- 
scopically unchanged.  The  estimation  is  carried  out  in  the  following 
way:  5  to  10  grams  of  the  sample  is  thoroughly  extracted,  first  with  ether, 
and  then  with  96  percent  alcohol,  and  then  treated  in  a  stoppered  flask 
with  from  10  to  20  times  the  weight  of  80  percent  sulfuric  acid.  The 
mixture  is  allowed  to  stand  for  six  hours,  and  is  well  shaken  at  intervals. 
By  this  time  the  cotton  is  completely  dissolved.  The  liquid  is  diluted 
with  cold  water,  and  any  wool  which  is  present  is  collected  on  a  fine  copper 
sieve,  washed  well,  finally  with  very  dilute  ammonia,  dried,  and  weighed. 
The  drying  may  be  done  either  at  about  225°  F.,  or  else  at  the  ordinary 
temperature  in  the  air.     In  the  latter  case  the  wool  will  contain  approxi 


ANALYSIS  OF  WOOL  AND  STAPLE  FIBER  MIXTURES  911 

mately  17  percent  of  moisture,  this  being  the  normal  amount  for  the  air- 
dried  fiber. 

It  has  also  been  suggested  to  use  the  percentage  of  nitrogen  as  a  basis 
for  the  analysis  of  wool-cotton  fabrics,  relying  on  the  assumption  that  the 
amount  of  nitrogen  in  wool  is  sufficiently  constant  to  make  this  factor 
an  accurate  measure  of  the  amount  of  wool  present.^  The  analysis  of  a 
large  number  of  samples  of  wool  fabrics  (yarns  and  cloth)  gave  a  nitrogen 
content  by  the  Kjeldahl  method  of  between  13.81  and  14.23  percent, 
or  a  mean  of  14.00  percent.  The  analysis  may  be  conducted,  therefore, 
by  first  removing  finishing  materials,  dirt,  and  grease  by  scouring  with 
soap,  drying  at  room  temperature,  weighing  out  about  5  grams  of  the 
sample  thus  prepared,  determining  the  percentage  of  nitrogen  by  the 
Kjeldahl  method,  and  calculating  the  amount  present  as  follows: 

^                    .        ,     1 00  X  percent  nitrogen  found 
Percentage  of  wool  =  — — rr . 

The  nitrogen  present  in  cotton  is  so  small  (only  0.25  percent  in  raw  cotton) 
that  its  amount  may  be  disregarded.  Even  the  amount  of  nitrogen  present 
in  the  dye  on  colored  samples  is  usually  so  small  as  to  be  negligible. 

2.  Analysis  of  Wool  and  Staple  Fiber  Mixtures. — Staple  fiber  is  a 
rather  recently  introduced  textile  material  and  consists  of  short  lengths 
of  artificial  silk  spun  into  a  yarn.  It  is  largely  used  in  connection  with 
wool  for  the  preparation  of  novelty  yarns  and  fabrics.  The  fiber  consists 
of  cellulose,  but  on  account  of  its  sensitiveness  to  alkalies  mixtures  of 
staple  fiber  with  wool  cannot  be  analysed  in  the  same  general  manner  as 
cotton  and  wool  mixtures.  Krais  and  Biltz  -  give  the  following  method  of 
analj^sis:  Mixtures  of  wool  and  staple  fiber  cannot  be  estimated  in  the 
same  manner  as  mixtures  of  wool  and  cotton  by  boiling  with  caustic  soda 
solution  and  weighing  the  residue  of  vegetable  fiber,  as  staple  fiber  from 
cuprate  silk  loses  6  percent  while  staple  fiber  from  viscose  silk  loses  7 
percent  by  the  alkahne  treatment.  Carbonising  with  acid  also  does  not 
give  good  results.  The  staple  fiber,  on  the  other  hand,  is  rapidly  and 
completely  removed  from  the  mixture  by  treatment  with  an  ammoniacal 
copper  solution.  The  solution  is  prepared  by  half  filling  a  stoppered  flask 
with  copper  turnings  and  adding  ammonia  (specific  gravity  0.905)  until 
nearly  full,  then  air  is  blown  in  with  occasional  shaking  for  several  days. 
The  resultant  deep  blue  solution  contains  1  percent  of  copper  oxide  and 
should  have  a  specific  gravity  of  0.925.  About  0.2  to  0.5  gram  of  the 
sample  is  weighed  into  a  porcelain  dish,  covered  with  10  cc.  of  the  copper 
solution,  and  stirred  from  time  to  time  during  half  an  hour.  The  solution 
is  decanted  and  the  residue   treated  for  a  further  half  hour  with  fresh 

1  Ruszkowky  and  Schmidt,  Chem.  Zeit.,  1909,  p.  949. 

2  Textile  Forschung,  1920,  p.  24. 


912  ANALYSIS   OF   TEXTILE   FABRICS   AND   YARNS 

copper  solution,  filtered,  washed  with  strong  ammonia  water,  followed 
by  10  percent  ammonia  water  and  finally  by  water.  The  residue  is  treated 
for  one  hour  with  10  percent  hydrochloric  acid,  washed  with  cold  and 
warm  water  until  neutral,  pressed  between  filter  paper  and  dried  at  110°  C. 
Wool  treated  in  this  manner  shows  a  loss  in  weight  of  only  0.42  percent. 

3.  Wool  and  Silk. — Silk  is  soluble  in  strong  hydrochloric  acid,  whereas 
wool  is  not  soluble  in  this  reagent  to  any  extent.  Hence  this  method  may 
be  utilised  for  the  quantitative  estimation  of  the  two  fibers  when  occurring 
together.  The  sample  is  first  treated  with  acid  and  alkali  in  the  manner 
already  described  in  order  to  remove  foreign  material  other  than  actual 
fiber.  It  is  then  dried  and  weighed;  then  immersed  in  cold  concentrated 
hydrochloric  acid  (about  40  percent  strength).  The  silk  dissolves  almost 
immediately.  The  residue  is  collected,  washed  thoroughly,  dried  again, 
and  weighed.  The  loss  in  weight  represents  silk,  while  the  weight  of  the 
residue  represents  wool. 

Another  method,  and  one  which  is  very  satisfactorj',  is  to  dissolve  the 
silk  by  treatment  with  an  ammoniacal  solution  of  nickel  oxide,  in  which 
reagent  the  silk  is  very  readily  soluble  even  in  the  cold.  It  only  requires  a 
treatment  of  about  two  minutes  to  completely  dissolve  the  silk  in  most 
silk  fabrics  other  than  plush.  Richardson  ^  found  that  by  this  treatment 
cotton  lost  only  0.45  percent  in  weight  and  wool  only  0.33  percent.  As 
silk  in  plush  goods  and  similar  fabrics  is  much  more  difficult  to  dissolve, 
it  is  recommended  to  boil  such  material  with  the  niekel  solution  for  ten 
minutes  under  a  reflux  condenser.  By  this  treatment  cotton  will  lose 
only  0.8  percent  in  weight.  The  nickel  solution  is  best  prepared  by  dis- 
solving 25  grams  of  crystallised  nickel  sulfate  in  80  cc.  of  water;  add 
36  cc.  of  a  20  percent  solution  of  caustic  soda,  carefully  neutralising  any 
excess  of  alkali  with  dilute  sulfuric  acid.  The  precipitate  of  nickel  hydrox- 
ide is  then  dissolved  in  125  cc.  of  strong  ammonia,  and  the  solution  diluted 
to  250  cc.  with  water. 

Instead  of  the  above  reagent,  a  boiling  solution  of  basic  zinc  chloride 
may  be  employed  for  the  purpose  of  dissolving  the  silk.  This  latter 
solution  is  obtained  by  heating  together  1000  parts  of  zinc  chloride,  850 
parts  of  water,  and  40  parts  of  zinc  oxide  until  complete  solution  is  effected. 
Richardson  recommends  that  the  sample  to  be  examined  should  be  plunged 
two  or  three  times  into  the  boiling  solution  of  zinc  chloride,  care  being 
taken  that  the  total  time  of  immersion  does  not  exceed  one  minute.  The 
zinc  chloride  solution  should  be  sufficiently  basic  and  concentrated  in 
order  to  obtain  good  results.  Under  the  best  conditions,  cotton  loses 
about  0.5  percent  in  weight,  and  wool  from  1.5  to  2.0  percent. 

The  chief  difficulty  attached  to  the  use  of  the  zinc  chloride  solution  is 
that  it  requires  a  long  and  tedious  washing  to  remove  all  of  the  zinc  salt 
"■Jour.  Sec.  Chem.  Ind.,  1893,  p.  430. 


SILK  AND   COTTON  913 

from  the  residual  fibers.  It  is  best  to  wash  with  water  acidulated  with 
hj^drochloric  or  acetic  acid. 

Darling  recommends  the  use  of  ammonio-nickel-oxycarbonate  as  a 
reagent  for  the  determination  of  silk  in  cotton-silk  or  cotton-wool-silk 
mixtures.  The  reagent  is  prepared  by  precipitating  the  nickel  oxycar- 
bonate  from  a  solution  of  nickel  suKate  (5  grams  in  100  cc.  of  water) 
with  a  saturated  solution  of  sodium  carbonate.  This  is  well  shaken,  filtered 
and  washed  with  water  until  free  from  sulfate  (tested  with  a  solution  of 
barium  chloride).  The  salt  is  allowed  to  dry  by  exposure  to  the  air, 
powdered,  and  bottled.  The  reagent  is  prepared  by  dissolving  the  salt 
in  20  percent  ammonium  hydroxide.  The  method  of  determining  the  silk 
in  the  sample  is  as  follows:  The  weighed  sample  (about  1  gram)  is  im- 
mersed in  25  cc.  of  the  reagent  and  well  stirred.  After  allowing  to  stand 
about  ten  minutes  in  a  warm  place  it  is  removed,  rinsed,  dried,  and  weighed. 
The  loss  is  due  to  the  dissolving  of  the  silk  in  the  reagent.  The  best 
method  of  washing  the  sample  is  to  place  it  in  a  Gooch  crucible  with  a 
layer  of  glass  wool  in  the  bottom.  The  glass  wool  is  readily  washed  free 
from  the  reagent  and  does  not  hold  it  as  will  asbestos.  Another  advantage 
of  glass  wool  over  asbestos  is  that  there  are  no  small  particles  to  adhere  to 
the  sample. 

Another  method  recommended  for  the  analysis  of  wool-silk  fabrics  is 
as  follows  •}  The  sample  is  treated  with  dilute  hydrochloric  acid,  then  soda 
ash  to  remove  finish,  dried,  and  weighed.  Concentrated  hydrochloric 
acid  (40  percent)  is  used  at  50°  C.  to  dissolve  out  the  silk.  The  wool  is 
washed,  dried,  and  weighed.  Another  method  is  to  boil  the  sample  for 
five  minutes  in  turbid  ammonia-nickel  hydroxide  solution,  remove  the 
wool,  wash  with  water,  and  with  hydrochloric  acid  to  remove  the  nickel, 
then  dry  and  weigh.  Boihng  basic  zinc  chloride  dissolves  silk  rapidly 
(wool  more  slowly).  The  wool  needs  washing  from  zinc  salts  with  dilute 
(1  percent)  hydrochloric  acid  and  water.  Silk  in  a  fiber  may  be  identified 
under  the  microscope. 

4.  Silk  and  Cotton. — The  methods  given  above  for  separating  silk 
from  wool  may  also  be  used  for  the  separation  and  quantitative  determina- 
tion of  silk  in  fabrics  containing  this  fiber  in  conjunction  with  cotton. 

Another  method  for  separating  silk  from  cotton  is  by  the  use  of  an 
alkaline  solution  of  copper  and  gh'cerol,  which  serves  as  an  excellent  solvent 
for  the  silk.  The  reagent  is  prepared  as  follows:  Dissolve  16  grams  of 
copper  sulfate  in  150  cc.  of  water,  with  the  addition  of  10  grams  of  glycerol; 
then  gradually  add  a  solution  of  caustic  soda  until  the  precipitate  of  copper 
hydrate  which  is  at  first  formed  just  redissolves.  This  solution  readily 
dissolves  silk,  but  is  said  not  to  affect  either  wool  or  the  vegetable  fibers. 
Richardson,  however,  has  found  that  cotton  heated  with  this  solution  for 

1  Posselt's  Textile  Jour. 


914  ANALYSIS   OF  TEXTILE   FABRICS   AND   YARNS 

twenty  minutes  (the  time  necessary  to  dissolve  silk  in  plush)  lost  from 

1  to  1.5  percent  in  weight  and  became  friable  and  dusty  on  drying;   while 

woolen  fabrics  lost  from  9  to  16  percent  in  weight.     Hence  the  reagent 

would  be  useless  in  the  analysis  of  fabrics  containing  wool. 

5.  Wool,  Cotton,  and  Silk. — Samples  of  shoddy  frequently  contain  all 

three  of  these  fibers  present  in  greater  or  lesser  amount,  and  often  it  is 

desirable  to  know  at  least  the  approximate  amounts  of  each  fiber  in  the 

mixture.     A   method   of   procedure   recommended   is   the   following:    A 

weighed  sample  of  the  material  is  boiled  for  thirty  minutes  in  a  1  percent 

solution  of  hydrochloric  acid,  washed,  and  then  boiled  for  thirty  minutes 

in  a  0.05  percent  solution  of  soda-ash.     This  preliminaiy  operation  is 

similar  to  that  above  described  in  the  preceding  analyses,  and  is  for  the 

purpose  of  freeing  the  fibers  as  far  as  possible  from  extraneous  foreign 

matter.     After  thorough  washing  and  air-drj'ing,  the  weight  of  the  sample 

is  again  taken,  and  the  loss  will  represent  miscellaneous  foreign  matter. 

The  sample  is  then  dried  at  105°  C.  to  constant  weight;  the  loss  in  weight 

will  represent  moisture.     The  sample  is  then  divided  into  two  weighed 

portions;    the  first  is  treated  for  five  minutes  with  a  boiling  solution  of 

basic  zinc  chloride  prepared  as  above  described,  washed  thoroughly  with 

acidulated  water,  then  with  fresh  water,  and  dried  at  100°  C.  again. 

The  loss  in  weight  will  represent  the  amount  of  silk  present.     The  second 

portion  of  the  sample  is  boiled  for  ten  minutes  in  a  5  percent  solution  of 

caustic  potash;  washed  thoroughly,  dried  at  100°  C.  and  weighed.     This 

weight,  with  a  correction  of  5  percent  added  to  it,  will  represent  the 

amount  of  cotton  present.     The  amount  of  wool  is  obtained  by  taking  the 

difference  between  the  total  weight  of  the  combined  fibers  and  the  sum 

of  the  weights  of  the  silk  and  cotton. 

Example :  ^ 

^  Grams. 

Sample  of  loose  shoddy  weighed 5 .  06 

Treated  with  acid  and  alkali,  and  air  dried 4.23 

Loss  as  foreign  matter 0 .  83 

Dried  at  100°  C 3.62 

Loss  as  moisture 0.61 

Divided  into  two  portions:  r^ 

^  Grams. 

(a)  weighed 1 .  95 

(6)  weighed 1.67 

(a)  treated  with  zinc  chloride 1 .  73 

Loss  as  silk 0.22 

(b)  treated  with  caustic  potash,  residue  as  cotton 0 .  34 

Loss  as  wool 1 .  33 


WOOL,   COTTON,   AND  SILK  915 

Hence  the  composition  of  this  sample  on  the  basis  of  dry  fiber  would  be: 

Percent. 

Silk 11.3 

Cotton 21.5 

Wool 67.2 


100.0 


Von  Remont  gives  the  following  method  for  anah'sing  fabrics  containing 
a  mixture  of  silk  wool,  and  cotton.  Four  quantities  (.4,  B,  C,  D)  of  2 
grams  each  of  the  air-dried  material  are  weighed  out.  Portion  A  is  kept 
aside,  and  each  of  the  other  three  is  boiled  for  fifteen  minutes  in  200  cc.  of 
water  containing  3  percent  of  hydrochloric  acid.  The  liquid  is  decanted, 
and  the  boiling  repeated  with  more  dilute  acid.  This  treatment  removes 
the  size  and  the  major  portion  of  the  coloring  matter.  Cotton  is  nearly 
always  decolorised  quite  rapidly,  wool  not  so  readily,  and  silk  but  imper- 
fectly, especially  with  black-dyed  fabrics.  The  samples  should  be  well 
washed  and  squeezed  in  order  to  remove  the  acid  liquor.  Portion  B 
is  set  aside.  Portions  C  and  D  are  then  placed  for  two  minutes  in  a  boiling 
solution  of  basic  zinc  chloride  (of  1.72  specific  gravity,  and  prepared  as 
above  described),  which  dissolves  any  silk  present.  They  are  then  washed 
with  water  containing  1  percent  of  hydrochloric  acid,  and  again  with  pure 
water,  until  the  washings  no  longer  show  the  presence  of  zinc.  Portion  C 
is  squeezed  and  set  aside.  Portion  D  is  boiled  gentl}'  for  fifteen  minutes 
with  60  to  80  cc.  of  caustic  soda  solution  (1.02  specific  gravity)  in  order  to 
remove  any  wool.  The  sample  is  then  carefully  washed  with  water.  The 
four  portions  are  next  dried  for  an  hour  at  100°  C,  and  then  left  exposed 
to  the  air  for  ten  hours  in  order  to  allow  them  to  absorb  the  normal  amount 
of  hygroscopic  moisture.  The  four  samples  are  then  weighed,  and  calling 
a,  h,  c,  and  d  their  respective  weights,  we  shall  have : 

a  — 6  =  dye  and  finishing  material; 
h—  c  =  silk; 
c— d  =  wool; 

d  =  cotton  (or  vegetable  fiber). 

This  method  is  open  to  objections,  as  the  plan  of  using  air-dried  matmal 
then  drying  at  100°  C,  and  subsequently  exposing  to  the  air  again  before 
reweighing,  is  liable  to  give  ver}'  erroneous  results.  Richardson  recom- 
mends that  the  samples  should  be  thoroughlj-  dried  at  100°  C.  before  being 
weighed  out,  and  the  treated  portions  should  subsequently  be  dried  at  the 
same  temperature  before  weighing.  In  order  to  prevent  the  sample  from 
absorbing  moisture  during  weighing,  it  is  best  to  use  a  weighing-bottle 
for  holding  the  dried  fiber.     The  sample  before  dn-ing  is  placed  in  a 


916 


ANALYSIS  OF  TEXTILE   FABRICS  AND   YARNS 


weighing-bottle  (the  weight  of  which  has  been  ascertained  previously) 
and  heated  in  an  air-oven  at  100°  C.  for  the  time  specified,  during  which 
the  cover  of  the  weighing-bottle  is  removed.  After  the  drying  process  is 
completed  the  stopper  is  replaced  in  the  weighing-bottle;  the  latter  is 
taken  from  the  oven,  allowed  to  cool,  and  is  then  weighed.  The  difference 
between  this  weight  and  the  weight  of  the  empty  bottle  will  give  the 
amount  of  dry  fiber. 

Treatment  with  a  boiling  solution  of  3  percent  hydrochloric  acid  for 
the  purpose  of  removing  finishing  materials  is  rather  too  severe,  as  the 
acid  will  act  on  the  wool  and  the  cotton,  sometimes  causing  considerable 
error.  Boiling  with  a  1  percent  solution  of  acid  for  ten  minutes  is  to  be 
preferred. 

The  following  is  given  as  a  practical  method  to  determine  if  shoddy 
contains  cotton  and  silk  fibers:  Boil  10  grams  of  the  shoddy  to  be  tested 
for  one  hour  in  400  cc.  of  water  containing  0.8  gram  of  alum,  0.3  gram  of 
tartar,  1  cc.  of  hydrochloric  acid,  0.1  gram  of  chrome,  and  0.05  gram  of 
bluestone.  Rinse  and  dye  with  0.3  gram  of  logwood  extract.  Rinse  and 
dry.  The  undyed  fibers  are  then  picked  out  and  examined;  cotton  will 
remain  white,  while  silk  will  be  colored  a  dingy  red. 

The  analysis  of  heavy  pile  fabrics  containing  a  mixture  of  fibers  is 
especially  difficult  unless  the  fabric  is  disintegrated.  In  the  analysis  of 
plush  for  the  amount  of  silk  present,  Richardson  suggests  treating  the 
sample  with  a  boiling  solution  of  basic  zinc  chloride  in  the  manner  pre- 
viously described;  but  when  silk  is  to  be  determined  in  light  fabrics 
(especially  in  the  presence  of  wool)  it  is  best  to  treat  the  sample  for  one  to 
three  minutes  with  a  cold  solution  of  ammoniacal  nickel  oxide.  He  gives 
the  following  comparison  of  results  in  the  analysis  of  a  sample  of  plush, 
using  the  three  different  methods  for  dissolving  the  silk: 


By  Solution 
of  Ammoniacal 
Nickel  Oxide. 

By  Solution 

of  Basic 

Zinc  Chloride. 

By  Copper- 
glycerol 
Reagent. 

Moisture  and  finish 

11.34 
45 .  60 
43.60 

11.00 
45.00 
44.00 

10.04 

Silk 

47.06 

Cotton 

42.90 

Samples  of  plush  with  hard  cotton  backs  may  best  be  analysed  by 
successive  treatment  with  acid  and  copper-glycerol  reagent.  On  other 
cotton  material,  however,  this  method  is  not  suitable;  nor  is  it  to  be  used 
in  the  presence  of  wool,  as  this  fiber  is  considerably  dissolved  by  the 
copper-glycerol  reagent. 


WOOL,    COTTON,   AND  SILK 


917 


The  following  table  by  Richardson  shows  a  comparison  of  the  three 
methods  employed  for  dissolving  silk : 


Actually 
Present. 

Percentage  Obtained  by 

Fiber. 

Ammoniacal 
Nickel  Oxide. 

Basic  Zinc 
Chloride. 

Copper-glycerol 
Reagent 

Silk 

Wool 

5.84 
76.31 

17.85 

5.92 
76.58 
17.50 

5.52 
80.08 
14.40 

18.80 
64  05 

Cotton 

17.15 

The  ammoniacal  nickel  oxide  solution  appears  to  give  the  best  results; 
hence,  in  analysing  a  sample  containing  silk,  wool,  and  cotton,  it  is  best 
first  to  remove  the  silk  by  means  of  this  reagent.  The  insoluble  residue 
left  after  this  treatment  is  boiled  with  a  1  percent  solution  of  hydrochloric 
acid,  washed  well  in  fresh  water,  and  then  boiled  for  five  to  ten  minutes 
in  a  2  percent  solution  of  caustic  potash,  which  is  sufficient  to  remove 
completely  the  wool  without  materially  affecting  the  cotton. 

From  experiments  conducted  by  the  author's  students  ^  the  following 
comparative  results  have  been  obtained  in  the  analysis  of  textile  materials 
by  the  different  methods  suggested. 

(a)  Analysis  of  wool-cotton  mixture: 


Fiber, 

Dissolving  Wool  by 
Caustic  Potash. 

Dissolving  Cotton  by 
Sulfuric  Acid. 

Theoretical. 

Found 

Theoretical. 

Found. 

Cotton 

Wool 

56.7 
43.3 

55.2 

44.8 

63.7 
36.3 

64.2 
35.8 

(6)  Analysis  of  wool-silk  mixture: 


Fiber. 

With  Hydrochloric 
Acid. 

With  Ammoniacal 
Nickel  Oxide. 

With  Basic  Zinc 
Chloride. 

Theoretical. 

Found. 

Theoretical. 

Found. 

Theoretical. 

Found. 

Wool 

Silk 

76.6 
23.4 

76.24 
23.76 

78.5 
21.5 

77.3 
22.7 

81.7 
18.3 

71.5 

28.5 

Collingwood,  Textile  World  Record,  vol.  29,  pp.  874,  1193. 


918  ANALYSIS  OF   TEXTILE   FABRICS  AND   YANRS 

(c)  Analysis  of  cotton-silk  mixture: 


Fiber. 

With  Hydrochloric 
Acid. 

With  Ammoniacal 
Nickel  Oxide. 

With  Basic  Zinc 
Chloride. 

Theoretical. 

Found. 

Theoretical. 

Found. 

Theoretical. 

Found. 

Cotton 

Silk 

70 
30 

67.5 
32.5 

65.12 

34.88 

64.42 
35.52 

71.11 

28.89 

70.13 

29.87 

(d)  Analysis  of  wool-cotton-silk  mixture; 


Fiber. 

Silk  by  Ammoniacal 
Nickel  Oxide;  Wool 
by  Caustic  Potash. 

Silk  by  Ammoniacal 

Nickel  Oxide;  Cotton 

by  Sulfuric  Acid. 

Theoretical. 

Found. 

Theoretical. 

Found. 

Wool 

41.2 
42.7 
16.1 

42.1 
41.6 
17.3 

41.0 
48.1 
10.9 

39.0 

Cotton 

Silk 

49.2 
11.8 

Fiber. 

Silk  by  Hydrochloric 
Acid;  Wool  by 
Caustic  Potash. 

Silk  by  Hydrochloric 
Acid;  Cotton  by 
Sulfuric  Acid. 

Theoretical. 

Found. 

Theoretical. 

Found. 

Wool 

38.9 
42.2 
18.9 

39.4 
38.0 
22.6 

28.6 
47.7 
23.7 

24.0 

Cotton 

Silk 

48.8 
27.2 

Fiber. 


Wool.. 
Cotton 
Silk... 


Silk  by  Basic  Zinc 

Chloride;  Wool  by 

Caustic  Potash. 


Theoretical. 


59.0 
26.3 
14.7 


Found. 


24.4 
18.1 


Silk  by  Basic  Zinc 
Chloride;  Cotton  by 
Sulfuric  Acid. 


Theoretical. 


63.5 
19.7 
16.8 


Found. 


61.6 
20.0 

18.4 


WOOL,   COTTON,   AND   SILK  919 

From  a  consideration  of  these  results  it  would  appear  that  in  the 
analysis  of  wool-cotton  mixtures  the  rapidity  with  which  the  caustic 
potash  dissolves  the  wool  gives  this  method  a  slight  preference  over  the 
somewhat  slower  one  of  destroying  the  cotton  by  treatment  with  sulfuric 
acid.  In  the  analysis  of  wool-silk  materials  the  treatment  with  hydro- 
chloric acid  is  slightly  better  than  by  the  use  of  ammoniacal  nickel  oxide. 
The  latter  reagent,  however,  is  the  better  to  use  for  dissolving  the  silk 
from  cotton-silk  mixtures,  as  the  cotton  is  too  readily  attacked  by  the 
concentrated  hydrochloric  acid.  In  the  analysis  of  wool-cotton-silk 
mixtures  the  only  proper  reagent  to  employ  for  dissolving  the  silk  is  the 
solution  of  ammoniacal  nickel  oxide.  Though  the  use  of  this  reagent  is 
rather  slow  compared  with  the  acid,  it  is  thorough,  and  its  action  on  the 
other  two  fibers  is  but  slight. 

The  following  table  shows  the  corrections  to  be  applied  in  the  calcula- 
tions of  results,  by  reason  of  the  action  of  the  different  reagents  on  the 
fiber  which  is  not  to  be  dissolved : 

Percent. 

(1)  Wool-cotto7i  mixtures: 

(a)  Wool  dissolved  by  caustic  potash ;  correction  for  loss  of  cotton  3 . 0 
(6)  Cotton  dissolved  bj'  sulfuric  acid ;  correction  for  loss  of  wool .  2.5 

(2)  Wool-silk  mixtures: 

(o)  Silk  dissolved  by  hydrochloric  acid;  correction  for  loss  of  wool  0.5 

(b)  Silk  dissolved  by  ammoniacal  nickel  oxide;  correction  for  loss 

of  wool 1.5 

(c)  Silk  dissolved  by  basic  zinc  chloride;    correction  for  loss  of 

wool 2.0 

(3)  Cotton-silk  mixtures: 

(a)  Silk  dissolved  by  hydrochloric  acid;    correction  for  loss  of 

cotton 4.0 

(b)  Silk  dissolved  by  ammoniacal  nickel  oxide;  correction  for  loss 

of  cotton 1.0 

(c)  Silk  dissolved  by  basic  zinc  chloride;    correction  for  loss  of 

cotton 15 

Allen  ^  also  recommends  the  ammoniacal  nickel  solution  for  use  in 
dissolving  silk  from  a  mixture  of  fibers.  His  method  of  analysing  a  textile 
sample  is  as  follows:  The  yarn  or  fabric  is  cut  up  very  fine  with  a  pair 
of  scissors,  and  thoroughly  dried  at  100°  C.  One  gram  of  the  material 
thus  prepared  is  treated  with  40  cc.  of  the  cold  ammoniacal  nickel  oxide; 
solution  for  two  minutes.  The  liquid  is  then  filtered,  and  the  residue, 
consisting  of  wool  and  cotton,  is  digested  for  two  or  three  minutes  in  a 
boiling  solution  of  1  percent  hydrochloric  acid.  It  is  then  washed  free 
from  acid,  dried  at  100°  C,  and  weighed.  To  separate  the  wool  from  the 
cotton  the  residue  is  boiled  with  about  50  cc.  of  a  1  percent  solution  of 
caustic  potash  for  ten  minutes,  and  the  solution  filtered.  The  residue, 
*  Comnier.  Org.  Anal.,  vol.  4,  p.  523, 


920  ANALYSIS  OF  TEXTILE  FABRICS  AND   YARNS 

consisting  of  cotton,  is  washed  free  from  alkali,  dried  at  100°  C,  and 
weighed. 

To  remove  gum  and  weighting  materials  from  goods  containing  silk, 
Richardson  recommends  treatment  of  the  sample  with  a  cold  2  percent 
solution  of  caustic  potash;  this  not  only  removes  any  gum,  but  also 
decomposes  any  Prussian  Blue  that  may  be  present  (as  a  bottom  under 
the  black  dye),  so  that  the  iron  may  be  more  easily  removed  by  subse- 
quent treatment  with  a  1  percent  solution  of  hydrochloric  acid.  Metalhc 
mordants,  however,  are  difficult  to  remove  in  this  manner,  and  at  best 
they  dissolve  only  imperfectly;  it  is  best  to  calculate  their  amounts  from 
the  quantity  of  ash  left  after  the  ignition  of  the  sample. 

Oily  matter  (and  also  certain  dyes)  may  be  best  removed  by  boiling 
successively  with  methylated  spirits  and  ether.  By  evaporation  of  the 
solution  so  obtained  the  amount  of  oil  and  fat  may  be  directly  determined. 

Hohnel  recommends  the  use  of  a  semi-saturated  solution  of  chromic 
acid  for  the  quantitative  separation  of  mixtures  containing  wool,  cotton, 
flax,  true  silk,  and  tussah  silk.  On  boiling  such  a  mixture  of  fibers  in  this 
solution  for  one  minute,  the  wool  and  true  silk  will  be  completely  dissolved 
leaving  as  a  residue  the  cotton,  flax,  and  tussah  silk. 

Other  methods  given  by  Hohnel  for  the  quantitative  analysis  of  fabrics 
containing  mixtures  of  the  fibers  mentioned  above  are  as  follows: 

(a)  Any  true  silk  is  first  removed  by  boiling  for  half  a  minute  in  concentrated 
hydrochloric  acid;  tussah  silk  is  next  removed  by  a  longer  boiling  in  the  acid  (three 
minutes) ;  the  residue,  consisting  of  wool  and  vegetable  fibers,  is  further  separated  in 
the  usual  manner  by  boiling  in  caustic  potash  solution. 

(6)  The  fabric  is  first  boiled  in  caustic  potash  solution,  which  dissolves  the  wool 
and  the  true  silk,  and  leaves  as  a  residue  (A)  tussah  silk  and  vegetable  fiber.  A 
second  sample  is  boiled  for  three  minutes  with  concentrated  hydrochloric  acid,  which 
dissolves  both  varieties  of  silk  and  leaves  as  a  residue  (B)  wool  and  vegetable  fiber. 
Residue  A  is  then  boiled  three  minutes  with  concentrated  hydrochloric  acid,  which 
dissolves  the  tussah  silk  and  leaves  the  cotton  as  a  final  residue.  By  subtracting 
this  amount  from  residue  B  the  amount  of  wool  is  obtained. 

(c)  A  sample  of  the  fabric  is  boiled  for  one  minute  in  a  semi-saturated  solution  of 
chromic  acid,  which  dissolves  the  true  silk  and  the  wool,  leaving  as  a  residue  the  tussah 
silk  and  vegetable  fiber.  From  this  residue  the  tussah  silk  is  removed  by  boiling  for 
three  minutes  in  concentrated  hydrochloric  acid,  leaving  the  vegetable  fiber  as  a  final 
residue.  A  second  sample  is  boiled  for  three  minutes  in  concentrated  hydrochloric 
acid,  which  dissolves  the  silks  and  leaves  the  wool  and  vegetable  fiber  as  a  residue. 
From  this  the  amount  of  wool  can  be  obtained  either  by  boiling  in  caustic  potash 
solution,  or  by  subtracting  the  cotton  previously  estimated.  Finally,  the  amount  of 
true  silk  may  be  found  by  subtracting  the  sum  of  the  other  constituents  from  the  total 
in  the  original  sample. 

6.  Distinction  between  Cotton  and  Linen. — As  it  is  often  desirable 
to  discriminate  between  these  two  fibers,  the  following  tests,  as  suggested 
by  various  authorities,  are  given.     These  chemical  tests,  however,  are 


DISTINCTION   BETWEEN   COTTON  AND  LINEN  921 

only  satisfactory  when  the  linen  is  in  an  unbleached  condition.  Bleached 
linen  will  show  practically  no  difference  from  cotton  in  the  tests,  as  in 
both  cases  the  cellulose  of  the  two  fibers  is  identical  in  its  chemical 
behavior.  The  most  satisfactory  test  to  distinguish  between  cotton  and 
linen  is  to  submit  the  fibers  to  a  microscopical  examination.  The  chief 
microscopical  distinctions  between  cotton  and  linen  fibers  are  in  the 
twist  and  smoothness  of  the  cotton  fiber,  the  presence  of  the  cuticle, 
the  blunt  point,  the  absence  of  joints,  and  the  irregular  granulations  and 
striations  on  the  fibers, 

(1)  The  fiber  is  burned: 
Cotton — burned  end  tufted. 
Linen — burned  end  rounded. 

(2)  The  fiber  is  immersed  in  concentrated  sulfuric  acid  for  two  minutes,  washea 
well  with  water,  then  with  dilute  ammonia  water,  and  dried  (Kindt  and  Lehnert) : 

Cotton — forms  a  gelatinous  mass  soluble  in  water. 
Linen — the  fiber  is  unaltered. 

(3)  The  fiber  is  treated  with  an  alcoholic  solution  of  madder  for  fifteen  minutes 
and  then  dried  between  two  sheets  of  blotting  paper: 

Cotton — becomes  bright  yellow  in  color. 
Linen — becomes  dull  orange  yellow  in  color. 

(4)  The  fiber  is  treated  with  an  alcoholic  solution  of  cochineal  for  fifteen  minutes  * 
Cotton — becomes  bright  red  in  color. 

Linen — becomes  violet  red  in  color. 

(5)  The  fiber  is  immersed  in  olive  oil  or  glycerol,  after  having  been  boiled  in  water 
and  well  dried. 

Cotton — remains  opaque  and  white. 

Linen — becomes  translucent  by  reason  of  the  oil  rising  by  capillary  action 
between  the  individual  filaments  of  the  fibers. 
In  this  test  the  fibers  after  saturation  with  oil  should  be  well  pressed  between  white 
filter-paper  to  remove  all  excess  of  the  liquid.  This  test  is  of  doubtful  value  and  is  not 
to  be  recommended  as  at  all  decisive.  According  to  Frankenstein  this  test  is  useful 
for  distinguishing  between  cotton  and  linen  cloth;  the  cloth  samples  are  saturated 
with  the  oil  and  placed  between  glass  plates  and  observed  with  a  magnifying  glass; 
the  linen  becomes  translucent  and  appears  fight  in  transmitted  light  and  dark  in 
reflected  light;  the  opposite  being  the  case  with  cotton. 

(6)  The  fiber  is  treated  with  an  alcoholic  solution  of  rosolic  acid,  and  then  with  a 
concentrated  caustic  soda  solution : 

Cotton — remains  colorless. 

Linen — becomes  rose  red  in  color. 

(7)  The  fiber  is  treated  with  iodine  and  sulfuric  acid  solutions: 
Cotton — becomes  pure  blue  in  color. 

Linen — gives  a  dull  blue  color.     This  test  is  satisfactory  only  on  unbleached 
linen. 

(8)  A  small  portion  of  the  sample  is  boiled  in  a  solution  of  equal  parts  of  water 
and  caustic  potash;  at  the  end  of  two  minutes  the  sample  is  raised  with  a  glass  rod, 
and  placed  between  several  thicknesses  of  filter-paper  to  remove  the  excess  of  water: 

Cotton — remains  white  or  is  a  pale,  clear  yellow  in  color. 

Linen — becomes  dark  yellow  in  color.     This  test  is  adapted  only  for  white  goods. 

(9)  Kuhlmann  recommends  the  use  of  a  cold  concentrated  solution  of  caustic 


922 


ANALYSIS  OF  TEXTILE  FABRICS  AND  YARNS 


potash  (specific  gravity  1.6).  This  causes  unbleached  cotton  to  shrink  and  curl  up, 
and  to  become  gray  or  dirty  white  in  color;  whereas  unbleached  linen  shrinks  more 
than  cotton,  and  acquires  a  yellowish  orange  color. 

(10)  The  fibers  are  boiled  in  water,  dried,  immersed  in  a  saturated  solution  of 
sugar  and  common  salt,  and  dried.     The  separate  threads  are  then  ignited: 

Cotton — leaves  a  black-colored  ash. 
Linen — leaves  a  gray-colored  ash. 

(11)  The  fibers  are  treated  with  a  1  percent  alcoholic  solution  of  Magenta  (Fuchsine), 
and  then  washed  with  a  weak  solution  of  ammonia  (see  Fig.  398) : 

Cotton — at  first  stained  a  rose  color  which  is  washed  out  by  the  ammonia. 
Linen — the  rose  color  is  permanent. 

(12)  Herzog  ^  recommends  the  following  test  to  distinguish  between  cotton  and 
linen  in  a  woven  fabric:  A  small  piece  of  the  cloth  is  cut  out  and  the  edges  are  fringed. 
The  sample  is  then  steeped  for  a  few  minutes  in  a  lukewarm  alcoholic  solution  of 

Cyanine;  it  is  then  washed  with 
water  and  treated  with  dilute  sul- 
furic acid.  By  this  treatment  the 
cotton  is  completely  decolorised, 
while  linen  retains  a  distinct  blue 
coloration.  To  make  the  blue  color 
still  more  distinct,  the  material 
should  be  washed  free  from  acid 
and  placed  in  ammonia.  The 
coloration  is  said  to  be  due  to  the 
presence  on  the  linen  fiber  of  frag- 
ments of  epidermis  which  readily 
absorbs  the  dyestuff . 

(13)  In  Behren's  method  of 
distinguishing  cotton  from  linen  in 
fabrics,  the  cloth  is  first  carefully 
boiled  in  water  and  then  in  a  dilute 
solution  of  soda  ash  to  remove 
finishing  compounds.     The  sample 


Fig.  398. — Appearance  of  Cotton-linen  Fabric 
with  Fuchsine  Test;  Linen  =  Red  Vertical 
Threads;  Cotton  =  White  Horizontal  Threads. 


is  then  heated  in  a  dilute  solution 
of  Methylene  Blue  until  a  rather 
dark  shade  of  blue  is  obtained. 
The  samples  are  then  washed  with 

water  until  the  cotton  has  become  almost  colorless  and  has  acquired  a  greenish  tone. 

Under  these  conditions  linen  will  remain  a  dark  blue  color.     Zetzsche  recommends 

this  test  as  quite  satisfactory.     Bismarck  Brown  or  Safranine  may  also  be  used  for  this 

test.     The  method,  however,  is  not  suited  for  bleached  fabrics. 

(14)  Herzog  also  gives  the  following  process:  steep  the  sample  for  ten  minutes  in  a 
10  percent  solution  of  copper  sulfate,  wash  well  and  then  steep  in  a  10  percent  solution 
of  potassium  ferrocyanide;  linen  will  become  colored  red,  while  cotton  not  taking  up 
the  copper  will  remain  white.  The  contrast  is  made  very  plain  after  rinsing  by  immers- 
ing the  sample  in  Canada  balsam. 

(15)  Behrens  also  recommends  the  use  of  Chrysophenine  in  combination  with 
Safranine  as  follows:  The  sample  to  be  tested  is  first  stained  in  a  hot  Safranine  solu- 
tion a  dark  rose  color.  It  is  then  washed  with  cold  water  and  placed  in  a  cold  solution 
of  Chrysophenine  slightly  alkaline  with  soda  ash.     Under  these  conditions,  flax  will 

'  Zeii.f.  Farben  und  Text.  Ind.,  1905,  p.  11. 


DISTINCTION   BETWEEN   COTTON   AND  LINEN 


923 


appear  a  dull  red  and  cotton  yellow.  When  treated  in  like  fashion  wool  and  silk  will 
be  colored  a  carmine  red,  jute  and  Manila  hemp  a  scarlet,  and  hemp  a  dull  red.  The 
solutions  of  the  dyes  are  best  made  up  fresh  for  each  test. 


Fig.  399. — Showing  Torn  Linen  Part  of  Mixed  Fabric. 


To  distinguish  the  nature  of  threads  in  fabrics  of  Hnen  or  mixed  linen 
and  cotton,  R.  Dantzer  recommends  the  following  commercial  tests: 

(1)  Test  by  Tearing. — The  linen  threads  are  much  stronger  than  cotton  and  if  it  is 

as  difficult  to  tear  a  fabric  warp-ways  as  it  is  filling-ways,  it  is  fairly  certain  that  the 

cloth  is  pure  hnen.      After 

a  little  practice    in  tearing 

cloths  one    can  distinguish 

the  difference  between  linen 

and  cotton    by  the    sound 

of  the   tear.     Linen    gives 

a    dull    sound,    while    the 

soimd    caused    by    tearing 

cotton    is    sharper.       The 

difference  in  the  appear- 
ance of  the  torn  projecting 

threads  is  very  perceptible. 

The    broken   ends    of    the 

linen     threads     (Fig.    399) 

have  a  pearly  appearance, 

the  fibers  are  irregular  and 

lustrous,  and   the   ends  of 

the  threads   are  untwisted, 

the  fibers  being  very  rigid. 

The  ends  of  the  cotton  threads  show  a  cleaner  break  (Fig.  400)  and  the  threads  are 

dull  in  appearance,  the  fibers  being  curled  instead  of  straight.  (2)  Test  by  Untwist- 
ing the  Yam. — Many  con- 
tent themselves  with  draw- 
ing out  several  threads  of 
warp  and  filling  and  un- 
twisting and  drawing  the 
thread  apart  so  as  to  expose 
the  fibers  to  view.  The 
cotton  fibers  are  shorter 
and  tangled  together,  while 
the  linen  fibers  are  much 
longer,  fairly  parallel,  and 
more  brilhant  and  less 
flexible.  (3)  Test  by  Ink.— 
This  process  consists  in 
dropping  a  small  quantity 
of  black  ink  on  the  sample. 
Figure  401  shows  the  form 
of  the  ink  spots  on  a  pure 
linen  fabric,  while  Fig.  402 

shows  the  form  of  the  spots  on  a  mixed  fabric  made  of  linen  and  cotton.     Each  spot 

is  approximately  the  same  size  as  the  black  circle  in  the  lower  corner  of  Fig.  401.     On 


Fig.  400.— Showing  Torn  Cotton  Part  of  Mixed  Fabric. 


924 


ANALYSIS   OF   TEXTILE   FABRICS   AND   YARNS 


Fig.  40L — Ink  Spots  on  Pure  Linen  Fal)ric. 


the  pure  linen  cloth  the  ink  spreads  in   all   directions  from   the  original  spot,  like  a 
drop  of  oil  on   a  sheet  of  paper.     On   the   mLxed  goods,  however,  it  spreads  in  the 

direction  of  the  hnen,  which  is 
more  porous  than  the  cotton. 
(4)  Test  by  Burning. — Linen  and 
cotton  have  each  a  cellulose  base, 
but  Stockhardt  has  called  atten- 
tion to  a  difference  between  the 
two  materials  when  they  are 
burned.  lie  claims  that  the  ends 
of  the  linen  threads  after  the 
flame  has  been  extinguished  are 
round  and  smooth,  while  the  ends 
of  the  cotton  threads  separate 
more  or  less  in  the  form  of  pincers. 
This  distinction  is  very  difficult 
to  make,  and  Dantzer  considers 
it  of  little  value,  and  recommends 
the  following:  The  fabric  is 
ravelled  to  form  a  fringe  half  an 
inch  long  of  warp  and  filling. 
The  fringe  is  then  set  on  fire  and 
the  flame  acts  differently  accord- 
ing to  the  nature  of  the  material.  In  an  all  linen  fabric  the  flame  burns  the  cloth 
both  at  the  top  and  side,  while  in  a  fabric  made  of  cotton  warp  and  linen  filling  the 
flame  from  the  linen  frii:£;o  attacks  the  cloth,  while  the  cotton  fringe  burns  doA\Ti  to 
the  filUng  without  attacking  the 
cloth.  (5)  Ted  by  0./.— This 
method  was  discovered  by 
Frankenstein.  The  cloth  is  first 
freed  from  the  finishing  material 
by  boiling  in  a  weak  solution  of 
carbonate  of  soda.  Af  xr  drying 
the  sample  is  satuiated  with  oil 
and  placed  on  a  plate  with  glass. 
When  the  air  bubbles  have  dis- 
appeared the  sample  is  covered 
with  a  smaller  piece  cf  glass,  the 
oil  is  squeezed  out,  and  the  cloth 
is  examined  by  hcldmg  it  be- 
tween the  observer  and  the  light. 
The  linen  fibers  become  trans- 
parent because  cf  the  thickness 
of  the  cell-walls  which  gives  a 
refraction  equal  to  that  of  the 
oil.  By  examining  it  between 
the  light  and    the    observer  it 

appears  clear,  but   when    examined   in    the   ordinary  manner  it  is  opaque.     Owing  to 
the  thickness  of  the  cell  walls  and  to  the  fact  that  the  air  is  imprisoned  in  the  cells,  tl'  ■ 
cotton  fiber  is  opaque  when  held  before  the  light  and  appears  clear  in  other  positicr 
(6)  Linen  and  cotton  cloths  of  the  same  thickness  differ  materially  in  weight,  lini.-. 
being  about  17  percent  heavier. 


Fig.  402. — Ink  Spots  on  Cotton-linen  Fabric. 


DISTINCTION   BET\\^EN   LINEN   AND  HEMP  925 

7.  Distinction  between  New  Zealand  Flax,  Jute,  Hemp,  and  Linen. — 

The  following  series  of  tests  is  recommended  to  distinguish  between  the 
fibers  in  question: 

(1)  The  material  is  immersed  in  chlorine  water  for  one  minute,  then  spread  on  a 
porcelain  dish,  and  several  drops  of  ammonia  water  added.  New  Zealand  flax  and  jute 
become  at  first  bright  red  in  color,  which  afterward  changes  to  dark  brown;  Unen  and 
hemp  acquire  a  much  lighter  shade,  such  as  clear  brown,  orange,  or  fawn.  This  method 
is  very  good  for  yarn  or  unbleached  cloth,  and  is  particularly  well  adapted  for  testing 
sail-cloth.  French  hemp  retted  in  stagnant  water  is  colored  a  much  deeper  shade 
than  the  same  kind  of  hemp  retted  in  running  water;  in  either  case  the  color  is  much 
darker  than  that  acquired  by  Unen.  For  testing  twine  this  method  is  said  to  give 
excellent  results,  but  in  bleached  material  the  difference  in  the  shades  produced  is  not 
very  marked. 

(2)  To  test  bleached  material,  the  sample  is  immersed  for  one  hour,  at  36°  C,  in 
nitric  acid  containing  nitrous  oxide.  New  Zealand  flax  assumes  a  blood  red  color, 
while  linen  or  hemp  is  tinted  pale  yellow  or  rose,  according  to  the  method  bj'  which 
it  was  originally  retted. 

(3)  A  sample  of  the  material  is  heated  in  concentrated  hydrochloric  acid.  Hemp 
and  Hnen  will  not  become  colored,  whereas  New  Zealand  flax  becomes  yellow  at  a  tem- 
perature of  30°  to  40°  C,  then  becomes  red,  brown,  and  finally  black. 

(4)  A  sample  of  the  material  is  treated  with  a  solution  of  iodic  acid.  Hemp  and 
linen  are  not  affected,  but  New  Zealand  flax  acquires  a  rose-red  color. 

(5)  Jute  is  distinguished  from  New  Zealand  flax  by  soaking  the  fibers  for  two  to 
three  minutes  in  a  solution  of  iodine  and  then  rinsing  several  times  in  a  1  percent 
solution  of  sulfuric  acid  to  remove  excess  of  iodine.  Jute  acquires  a  characteristic 
reddish  brown  color;  New  Zealand  flax  becomes  clear  yellow  in  color;  hemp  acquires 
a  fight  yellow  color,  and  linen  a  blue  color.  It  will  be  found  best  to  untwist  the  separate 
threads  previous  to  this  treatment. 

(6)  Jute  may  be  distinguished  from  flax  and  hemp  by  warming  in  a  solution  con- 
taining nitric  acid  and  a  little  potassium  chromate,  then  washing  and  warming  in  a 
dilute  solution  of  soda  ash,  and  washing  again.  The  fibers  are  then  placed  on  a  micro- 
scope shde,  and  when  the  water  has  evaporated  a  drop  of  glycerol  is  added.  In  a  short 
time  the  characteristic  structure  of  jute  will  be  easily  observable,  and  under  the 
polariscope  (with  a  dark  field)  the  jute  fiber  will  show  a  uniform  blue  or  yellow  color, 
whereas  linen  and  hemp  will  show  a  play  of  prismatic  colors.  Also  with  phloroglucinol 
and  hydrochloric  acid,  jute  is  stained  an  intense  red,  while  linen  remains  uncolored 
and  hemp  acquires  only  a  reddish  tint. 

8.  Distinction  between  Linen  and  Hemp. — To  distinguish  accurately 
between  linen  and  hemp  it  is  best  to  have  recourse  to  a  microscopical 
examination.  The  linen  fibers  will  appear  quite  regular  and  with  a 
lumen  which  is  often  reduced  to  a  mere  line,  while  the  hemp  fiber  shows 
a  very  large  lumen,  and  presents  a  rather  irregular  surface.  With  the 
iodine-sulfuric  reagent  hemp  gives  a  green  coloration,  while  linen  gives 
a  blue;  with  nitric  acid  linen  gives  no  color,  while  hemp  shows  a  pale 
yellow  coloration.  The  ends  of  the  linen  fibers  are  pointed,  while  those 
of  hemp  are  enlarged  and  spatula-shaped.  Hohnel  gives  the  following 
distinctions  between  linen  fibers  and  those  of  hemp:    (1)  they  do  not 


926  ANALYSIS   OF  TEXTILE   FABRICS  AND   YARNS 

form  thick  bundles,  but  are  more  separated  from  one  another;  (2)  the 
cross-section  does  not  exhibit  an  external  yellowish  layer  of  rind,  when 
it  is  treated  with  iodine  and  sulfuric  acid;  (3)  it  gives  the  pure  cellulose 
reaction;  (4)  there  is  nearly  always  present  a  plentiful  yellowish  content 
of  protoplasm,  which  the  hemp  fiber  very  seldom  possess;  (5)  the  fibers 
end  in  sharp  points. 

By  a  determination  of  the  methyl  value  it  is  possible  to  distinguish 
chemically  between  unbleached  flax  and  hemp.  The  phloroglucinol  test 
cannot  be  relied  on  to  distinguish  between  these  two  fibers. 

According  to  Hanausek  ^  linen  and  hemp  may  be  best  distinguished 
microscopically  by  the  use  of  a  solution  of  potassium  bichromate.  The 
fibers  of  linen  swell  up  more  rapidly  than  those  of  hemp,  and  the  dark 
patches  formed  on  the  surface  are  more  pronounced. 

The  question  of  the  distinction  between  fibers  of  flax  and  hemp  is 
such  an  important  one  in  practical  microscopy  that  it  might  be  worth 
while  at  this  point  to  introduce  the  remarks  of  C.  Cramer,  who  published 
an  excellent  microscopical  study  of  these  two  fibers  in  the  Zurich  Polytech- 
nical  Journal  for  1881.  The  length  and  thickness  of  the  fibers  under 
examination  cannot  be  considered  as  points  of  much  value,  the  differences 
in  these  measurements  being  so  small  as  to  be  practically  negligible. 
Vetillard  has  already  given  the  thickness  of  hemp  as  50  and  flax  as  37 
microns,  but  the  mean  value  is  about  the  same  for  both  fibers,  which  is  in 
support  of  Cramer's  view ;  the  latter  found  a  mean  thickness  of  46  microns 
for  flax  fibers.  On  the  other  hand,  there  is  a  constant  difference  in  the 
shape  of  the  fiber  ends ;  and  this  difference  is  sufficient  to  provide  a  sharp 
distinction  between  flax  and  hemp.  This  distinction  had  already  been 
pointed  out  by  Schacht,  and  latter  recognised  more  definitely  by  Vetillard. 
Hohnel  claims  that  each  single  fiber  of  hemp  can  readily  be  distinguished 
from  flax  by  an  examination  of  the  ends.  If  the  maceration  of  the  material 
is  carried  to  the  proper  stage,  it  is  easy  to  find  a  large  number  of  ends; 
usually,  however,  the  maceration  is  carried  too  far,  hence  the  fibers  become 
broken  at  their  jointed  points,  and  then  it  becomes  difficult  to  find  the 
natural  ends  of  the  fibers  among  the  broken  pieces.  The  forked  ends  of 
hemp  are  also  not  of  such  frequent  occurrence.  Observations  have  shown 
that  among  3  to  4  ends,  it  is  almost  certain  to  find  a  forked  one,  while 
with  flax  nothing  similar  is  to  be  noticed.  The  reason  why  the  forked 
ends  are  so  frequently  overlooked  is  that  one  of  the  prongs  is  usually  very 
much  smaller  than  the  other,  and  often  hes  above  or  under  the  fiber. 
Consequently  in  making  the  examination  it  is  best  to  twist  the  fiber 
around.  Hence  Hohnel  does  not  agree  with  Cramer  when  he  attributes 
no  importance  to  the  examination  of  the  ends  in  uncertain  cases.  Nor 
does  Hohnel  agree  with  Cramer  in  working  with  a  magnification  of  150 
^Zeil.  Farb.  Ind.,  1908,  p.  105. 


DISTINCTION  BETWEEN  LINEN  AND  HEMP  927 

to  400;  he  finds  the  ends  of  the  fibers  with  a  magnification  of  20  to  30, 
and  then  notes  down  the  appearance  when  viewed  with  a  power  of  300  to 
400.  He  also  dissents  from  Cramer  with  respect  to  the  shape  of  the  cross- 
section,  stating  that  though  variations  in  this  will  occur,  yd  one  can 
readily  be  convinced  by  observation  that  the  two  fibers  may  be  very 
nicely  distinguished  by  means  of  their  cross-sections.  With  flax  the  form 
of  cross-section  which  predominates  by  far  is  the  previously  described 
isodiametric,  sharp-edged,  polygonal  form,  with  the  lumen  appearing  as 
points;  while  hemp,  on  the  other  hand,  has  the  contrary  form;  so  it  is 
Hohnel's  opinion  that  the  shape  of  the  section  is  a  very  useful  observation. 
That  every  individual  fiber  does  not  possess  the  normal  form  is,  as  a  matter 
of  course,  reasonable,  and  is  to  be  expected. 

As  to  the  breadth  of  the  lumen,  Hohnel  agrees  with  Cramer  in  opposi- 
tion to  Wiesner,  that  it  has  no  special  value,  as  might  be  deduced  from 
what  has  already  been  said  in  its  description.  With  respect  to  the  strati- 
fied form  of  the  wall,  which  according  to  most  writers  is  more  distinct  in 
the  case  of  hemp  than  in  flax,  Hohnel  also  agrees  with  Cramer,  in  the 
opinion  that  the  difference  is  too  slight  to  serve  as  a  criterion.  Yet  there 
are  two  conditions  to  be  considered  here  with  which  Cramer  was  not 
familiar.  By  the  action  of  Vctillard's  reagent  on  the  cross-section,  not 
only  in  the  inner  strata  are  there  useful  differences  to  be  observed,  but 
also  the  yellow  outer  layers  are  noticeable  in  the  case  of  hemp,  and  entirely 
lacking  with  flax.  With  regard  to  the  action  of  the  ordinary  reagents  for 
cellulose  or  woody  tissue,  it  must  be  said  that  when  no  attention  is  paid 
to  the  concentration  of  the  reagents,  all  possible  colors  can  be  obtained 
with  iodine  and  sulfuric  acid,  for  instance.  Therefore  the  reagents 
employed  must  be  prepared  as  definitely  stated  in  the  test,  and  then  it  is 
always  possible  to  obtain  definite  reactions  with  hemp  and  flax  which 
will  show  differences,  both  with  respect  to  the  longitudinal  section  and 
the  cross-section.  Consequently  it  is  Hohnel's  opinion  that  it  is  quite 
possible  to  microscopically  distinguish  with  certainty  between  pure  flax 
fibers  and  pure  hemp  fibers. 

The  parenchym  which  surrounds  the  bast  fibers  of  hemp  is  rich  in 
star-shaped  crystal  lumps  of  calcium  oxalate,  which  is  not  the  case  with 
flax.  Furthermore,  there  are  to  be  found  between  the  fibers,  as  well  as 
inside  of  the  bast,  numerous  long-shaped  cells  filled  with  a  remarkable 
reddish-brown  substance,  which  is  insoluble  in  the  usual  solvents  (such 
as  caustic  potash,  alcohol,  ether,  benzine,  sulfuric  acid,  etc.).  These 
cells  of  coloring  matter  (or  tannin)  are  lacking  in  flax.  Finally,  the 
epidermis  of  hemp  is  constituted  quite  differently  from  that  of  flax.  The 
epidermis  of  hemp  consists  of  many  small  cells,  between  which  only  very 
small  openings  occur  (in  1  cm.-  there  are  probably  about  12).  These  are 
bounded  by  only  two  crescent-shaped  end  cells,  and  appear  on  the  epider- 


928  ANALYSIS  OF   TEXTILE   FABRICS   AND   YARNS 

mis  as  semi-globular  warts.  There  are  also  to  be  found  on  the  epidermis 
of  hemp  single-celled,  bent,  and  very  thick  hairs.  In  the  case  of  flax,  the 
epidermis  contains  about  3000  fissure  openings  to  the  sq.  cm.,  which  exhibit 
just  two  pairs  of  crescent-shaped  end  cells.  The  fissure  openings  of  hnen 
do  not  lie  on  a  protuberance,  but  on  the  same  level  with  the  rest  of  the 
epidermal  cells.  Furthermore,  the  epidermis  of  linen  possesses  scarcely 
any  hairs,  and  its  cells  are  larger  than  those  of  hemp.  The  cells  of  the 
former  measure  about  140  microns  in  length  and  30  microns  in  breadth, 
whereas  those  of  the  latter  are  only  70  microns  in  length  and  20  microns  in 
breadth. 

According  to  Behrens,  flax  and  hemp  may  be  distinguished  by  the  use 
of  Benzopurpurine  lOB  in  combination  with  Malachite  Green.  The  sample 
is  placed  on  the  object  glass  with  a  small  granule  of  Malachite  Green  and 
a  drop  of  acetic  acid  and  heated  to  boiling;  after  cooling,  the  excess  of 
dye  is  soaked  up.  The  sample  is  washed  with  hot  water  and  then  with 
cold  water.  Then  the  green-colored  fiber  is  steeped  in  a  solution  of 
Benzopurpurine  lOB  made  slightly  alkaline  with  soda  ash.  Hemp  will 
appear  multicolored  as  an  impure  mixture  of  greenish  blue  and  violet, 
while  flax  will  appear  red,  though  any  protoplasmic  residues  in  the  lumen 
will  appear  green. 

Nodder  ^  has  observed  that  the  striations  noticed  in  the  cell-wall  of 
flax  and  ramie  always  form  left-handed  spirals,  whereas  those  in  the  case 
of  hemp  and  jute  always  form  right-handed  spirals.  Further  it  was 
found  that  if  a  wet  fiber  is  held  with  the  free  end  toward  the  observer, 
flax  and  ramie  are  always  seen  to  twist  in  a  clock-wise  direction  when 
drying,  while  hemp  and  jute  always  twist  in  the  reverse  direction.  This 
distinction  forms  the  basis  of  a  valuable  naked-eye  test  for  distinguishing 
between  flax  and  hemp.  The  present-day  tendency  to  prepare  composite 
yarns  of  hemp  and  linen  in  various  proportions  demands  a  reliable  test 
between  these  two  fibers.  Nodder  believes  that  in  these  twisting  properties 
is  to  be  found  a  ready  means  of  accurately  distinguishing  between  these 
two  fibers  in  any  stage  of  their  manufacture.  To  carry  out  the  test  the 
fibers  are  first  well  teased  out  of  the  material  under  examination  and  then 
soaked  for  some  minutes  in  warm  water.  The  use  of  a  pair  of  fine-tipped 
forceps  and  a  dark  background  is  recommended.  As  far  as  possible 
only  single  fibers  should  be  examined,  and  care  should  be  taken  to  make 
sure  that  the  twisting  is  due  to  drying  and  not  to  wetting.  To  get  the 
best  results  it  is  well  to  hold  the  thoroughly  moistened  fiber  over  a  hot 
plate  and  observe  the  direction  of  the  drying  twist.  The  first  movement 
observed  in  warming  a  wet  fiber  is  a  slight  twist  in  the  wet  direction, 
but  very  soon  the  steady  drying  twist  sets  in.     In  applying  this  test  to 

^Jour.  Text,  hist.,  1922,  p.  161. 


DISTINCTION   BETWEEN   MANILA   HEMP  AND  SISAL  929 

cotton  it  was  found  that  the  twist  may  be  in  either  direction,  and  usually- 
different  parts  of  the  same  fiber  twist  in  different  directions. 

9.  Distinction  between  Manila  Hemp  and  SisaL — In  their  character- 
istics these  two  fibers  are  very  similar  and  it  is  quite  difficult  to  distinguish 
between  them.  This  may  be  done,  however,  with  more  or  less  accuracy 
by  an  observation  of  the  color  of  the  ash,  which  in  the  case  of  Manila 
hemp  is  grayish  black,  while  sisal  leaves  a  white  ash. 

Manila  hemp  is  the  principal  fiber  used  for  the  better  grades  of  cordage 
and  it  is  frequently  adulterated  by  mixture  with  the  lower  grades  of  the 
coarse  vegetable  fibers.  As  a  result  of  a  research  conducted  by  the 
National  Bureau  of  Standards  an  excellent  and  satisfactory  test  has  been 
devised  for  distinguishing  between  Manila  hemp  and  other  fibers  used 
to  adulterate  Manila  rope. 

The  principle  of  the  test  is  that  if  a  bundle  of  fibers  from  a  strand 
of  rope  is  treated  in  the  manner  to  be  described,  the  Manila  fibers  turn 
a  russet-brown,  and  the  other  fibers  turn  a  cherry-red.  There  will  be 
slight  differences  of  manipulation  according  to  whether  the  fiber  has  been 
oiled  or  not;  in  other  words,  whether  one  is  testing  a  sample  of  fiber 
before  it  has  been  made  into  rope,  or  treating  a  strand  of  rope  itself. 

There  is  required  for  this  test,  ether,  a  solution  of  bleaching  powder, 
glacial  acetic  acid  and  strong  ammonia  water,  together  with  a  vessel  of 
clear  water  for  rinsing  purposes.  The  test  is  carried  out  in  the  following 
manner:  A  solution  of  bleaching  powder  acidulated  with  a  few  drops  of 
glacial  acetic  acid  is  first  prepared.  The  different  reagents  should  be 
contained  in  suitable  vessels  standing  in  a  row,  namely,  ether,  bleaching 
powder  solution,  water,  alcohol  and  ammonia.  Immerse  the  fibers 
in  the  acidulated  bleaching  powder  solution  for  twenty  seconds.  The 
fibers  are  then  rapidly  rinsed  in  water,  then  in  alcohol,  and  the  treated 
portion  is  held  an  inch  or  two  above  the  surface  of  the  strong  ammonia. 
The  Manila  fiber  turns  brown,  and  all  other  fibers  turn  cherry-red,  as 
mentioned  before.  In  most  cases  the  colors  remain  for  a  sufficient  length 
of  time  so  that  a  practiced  manipulator  can  separate  them,  pulling  out  the 
brown  fibers  or  the  red  ones,  as  the  case  may  be.  The  cherry-red  color 
however,  is  not  permanent,  but  disappears  on  prolonged  exposure  to  the 
ammonia  fumes.  If  the  fibers  are  removed  as  soon  as  the  full  color 
develops,  it  will  last  for  an  hour  or  so  and  make  quantitative  estimation 
of  adulteration  easy. 

If  a  sample  of  rope  is  being  treated,  it  is  best  to  start  with  one  yarn, 
and,  to  remove  the  oil,  ether  is  poured  down  the  yarn.  After  waving 
through  the  air  for  a  minute  or  two  to  expel  most  of  the  ether,  it  is  then 
ready  for  the  course  described.  There  is  in  some  instances  such  a  rapid 
change  of  color  that  one  full  yarn  is  too  much  to  handle  at  one  time. 
It  is  best,  therefore,  to  start  with  a  few  fibers  from  the  yarn.     This  enables 


930  ANALYSIS  OF  TEXTILE   FABRICS  AND   YARNS 

a  rapid  separation  to  be  made,  and  the  sample  is  then  ready  for  the 
following  procedure:  After  having  separated  the  fibers  as  described,  it 
is  well  to  take  the  other  end  and  go  through  the  same  course  of  procedure, 
except  for  the  following  modification:  Instead  of  holding  the  fibers  over 
the  ammonia,  it  is  well  to  immerse  them  in  the  ammonia.  If  the  selection 
has  been  properly  made,  all  those  fibers  characterised  as  Manila  will  show 
the  brown  color,  and  all  the  fibers  selected  as  non-Manila  will  show  the 
red  color.  The  objection  to  making  just  the  one  test  is  that  the  red  when 
so  formed  tends  to  degrade  too  quickly  to  permit  picking  out  from  a 
bundle  of  fibers.     It  is  well  to  make  this  test  as  a  confirmation. 

The  bleaching  powder  solution  is  made  in  the  following  manner. 
In  a  large,  clean  porcelain  mortar  is  placed  one  part  of  bleaching  powder, 
and  thereto  is  added,  a  little  at  a  time,  with  constant  grinding,  five  parts 
of  water.  After  a  smooth  paste  has  been  made,  it  is  transferred  to  a  tall 
cylinder  and  allowed  to  stand  away  from  the  light  for  a  few  hours  until 
there  is  a  clear  solution.  This  bleaching  powder  solution  should  be  kept 
in  an  amber-colored  bottle  in  the  dark,  and  it  will  last  for  several  months. 
When  the  tests  are  to  be  made,  it  is  well  to  pour  an  ounce  or  two  of  the 
solution  into  a  tumbler  or  beaker,  and  add  about  one  cc.  of  glacial  acetic 
acid.  This  acidulation  should  not  be  attempted  with  any  other  acid 
than  the  one  specified.  Attempts  to  use  hydrochloric  acid  and  the  like 
spoil  the  test.  The  solution  so  made  is  good  for  an  hour  or  two,  but  should 
be  made  up  fresh  each  time  a  series  of  tests  are  to  be  undertaken. 

This  test  has  been  established  on  samples  of  Manila  from  all  provinces, 
and  on  samples  which  have  been  kept  long  periods  of  time,  together  with 
fresh  samples.  Very  little  experience  will  be  required  to  establish  the 
satisfactory  nature  of  the  tests.  There  is  room  for  a  considerable  degree 
of  manipulative  skill  in  the  picking  out  of  the  fibers,  and  one  who  has  had 
practice  in  microscopic  methods  should  possess  the  requisite  degree  of 
dexterity. 

The  question  sometimes  comes  up  whether  a  sample  of  rope  is  all 
Manila  or  not,  and  when  this  is  the  question  it  is  best  to  practice  the 
modification  where  the  fiber  bundle  is  immersed  in  the  ammonia.  This 
enables  one  to  decide  whether  he  is  dealing  with  mixed  fibers  or  not. 
If  they  are  all  red,  then  there  is  no  Manila.  If  they  are  all  brown,  then 
the  sample  is  Manila  with  no  other  fibers.  If  there  is  a  mixture,  the 
course  previously  described  should  be  followed  vigorously.  Each  time 
a  series  of  tests  is  to  be  undertaken,  a  clean  vessel  should  be  used,  and  the 
various  solutions  poured  therein.  Ammonia  exposed  to  the  air  tends 
to  lose  strength,  alcohol  takes  water  from  the  air,  and  the  like.  The  only 
thing  requiring  any  appreciable  length  of  time  is  the  preparation  of  the 
bleaching  powder  solution,  and  as  stated  a  solution  once  made  up  is  good 
for  several  months. 


TESTING  FOR  LIGNIN  931 

When  it  becomes  necessary  to  estimate  the  amount  of  the  different 
fibers  in  a  given  mixture,  the  separations  are  made  as  described,  after 
which  the  Manila  on  the  one  hand  and  the  non-Manila  on  the  other  are 
rinsed  first  with  water,  then  with  alcohol,  then  with  ether,  and  dried  at 
110°  C.  After  being  allowed  to  cool  for  an  hour  or  two,  they  may  be 
weighed  and  the  portion  of  Manila  and  non-Manila  fibers  directly 
estimated  by  weight. 

It  has  been  ascertained  that  all  varieties  of  sisal,  including  true,  false, 
istle,  pita  and  maguey  give  the  red  color,  as  do  New  Zealand  flax,  Mauri- 
tius hemp,  and  Sansevieria  fiber.  Tests  on  mixtures  of  known  compo- 
sition have  resulted  very  satisfactorily. 

10.  Testing  for  Lignin. — Ligneous  matter  (derived  from  woody  tissue) 
may  be  detected  in  admixture  with  other  fibers  in  the  following  manner: 

(1)  On  exposing  the  moistened  sample  to  the  action  of  chlorine  or  bromine,  and 
then  treating  it  with  a  neutral  solution  of  sodium  sulfite,  a  purple  color  will  be  produced. 

(2)  If  the  sample  be  moistened  with  an  aqueous  solution  of  aniline  sulfate,  an 
intense  yellow  color  will  be  produced. 

(3)  If  the  sample  be  moistened  with  a  solution  of  phloroglucinol  of  ^  percent  strength, 
and  then  with  hydrochloric  acid,  an  intense  violet-red  color  will  be  produced.  Solu- 
tions of  resorcinol,  orcinol,  and  pyrocatechol  act  in  a  similar  manner. 

(4)  Woody  fiber  when  boiled  in  a  solution  of  stannic  chloride  containing  a  few 
drops  of  pyrogallol  gives  a  fine  purple  color,  which  is  easily  seen  under  a  magnifying- 
glass. 

(5)  If  the  sample  is  treated  with  a  mixture  of  equal  parts  of  semi-normal  ferric 
chloride  and  semi-normal  ferric  ferricyanide  solutions,  a  blue  color  is  formed  the  inten- 
sity of  which  will  indicate  the  amount  of  lignification.  The  reagents  must  not  be  used 
in  higher  concentrations,  as  then  even  pure  cotton  cellulose  will  be  stained  a  faint  blue. 

In  testing  for  lignin  the  best  results  are  obtained  by  Cross  and  Bevan's 
method.  The  moist  fibers  are  placed  in  a  suction  funnel,  chlorine  is 
passed  over  them  and  then  sulfurous  acid  gas  is  drawn  down  through  the 
tube  by  suction.  The  fibers  are  then  washed  with  water,  and  afterward 
with  a  2  percent  solution  of  sodium  sulfate.  The  yellow  coloration  pro- 
duced by  the  action  of  the  chlorine,  and  also  the  red  which  appears  after 
the  addition  of  sodium  sulfate  are  very  distinct.  Cotton,  oxycellulose,  and 
hydrocellulose  are  not  colored,  but  lignified  fibers  are  all  colored  more  or 
less  according  to  their  content  of  lignin. 

Another  sharply  marked  lignocellulose  reaction  can  be  produced  by 
the  use  of  para-nitrophenyl  sodium  nitrosamine.^  The  2  percent  solution 
of  the  reagent  is  left  in  contact  with  the  fibers  for  fifteen  minutes,  then 
removed  by  suction.  The  fibers  are  washed  and  saturated  with  1  percent 
caustic  soda  solution.  The  reaction  gives  bright  to  dark  lilac  shades 
according  to  the  degree  of  lignification;  the  weaker  the  lilac  color  the 
purer  the  cellulose.  The  colorations  are  still  more  distinct  when,  instead 
'  Schwalbe,  Zeit.f.  ang.  chim.,  1902. 


932  ANALYSIS   OF   TEXTILE   FABRICS   AND   YARNS 

of  the  nitrosamine,  a  diazo  solution  is  used,  which  is  prepared  from  the 
nitrosamine  solution  by  the  action  of  hydrochloric  acid  and  para-nitrodiazo- 
benzene  chloride.  The  fibers  are  soaked  for  fifteen  minutes  with  the  re- 
agent as  a  2  percent  solution;  remove  by  suction  and  wash  with  cold  water. 
According  to  the  degree  of  lignification  the  color  will  be  more  or  less 
brown,  pure  cellulose  being  left  white. 

The  degree  of  lignification  may  also  be  estimated  by  a  solution  of 
primuline;  0.25  gram  of  the  fibers  are  dyed  for  one  hour  with  15  cc.  of 
primuline  solution  (12  grams  per  liter)  to  which  is  added  5  cc.  of  ^  percent 
salt  solution.  Wash  and  place  in  an  acid  solution  of  sodium  nitrite 
(0.04  percent  sodium  nitrite  solution  and  5  cc.  of  ^  percent  sulfuric  acid 
solution).  Treat  cold  for  fifteen  minutes,  then  wash  with  cold  water 
and  stain  with  10  cc.  of  a  dilute  beta-naphthol  solution  (0.014  percent). 
With  cotton  a  red  color  is  developed,  but  with  lignified  fibers  the  red  color 
diminishes  in  proportion  to  their  impurity. 

Klason's  reaction  for  lignin  is  carried  out  as  follows:  22  mgms.  of  fiber 
are  dissolved  in  5  cc.  of  concentrated  sulfuric  acid  in  a  glass-stoppered 
cylinder.  The  intensity  of  the  brown  color  will  indicate  the  degree  of 
lignification. 

The  Maule  reaction  for  lignin  is  also  a  very  good  one;  the  fibers  are 
soaked  in  a  0.1  percent  solution  of  potassium  permanganate  for  fifteen 
minutes,  thoroughly  washed  and  placed  in  hydrochloric  acid  (specific 
gravity  1.06)  until  the  brown  deposit  of  manganese  oxide  is  completely 
dissolved.  After  washing,  ammonia  gas  is  passed  over  the  fibers.  Ligni- 
fied tissue  acquires  a  red  color  by  this  treatment. 

11.  Detection  of  Cotton  in  Kapok. — The  practice  of  some  manufac- 
turers of  mixing  comber  waste  with  kapok  in  order  to  reduce  the  cost  of 
the  material  has  made  it  desirable  that  some  simple  test  should  be  available 
for  determining  whether  such  mixture  has  taken  place.  As  kapok  is  a 
partly  lignified  fiber  it  gives  a  yellow  to  yellowish  brown  coloration  when 
treated  with  iodine  and  sulfuric  acid,  whereas  cotton  gives  a  blue  coloration 
with  this  reagent.  This  same  test  also  serves  to  distinguish  the  general 
class  of  Bombax  cottons  from  ordinary  cotton. 

The  only  direct  test  to  distinguish  cotton  and  kapok  is  by  means  of  the 
microscope.  The  cotton  fiber  is  seen  as  a  somewhat  twisted,  rather  flat 
ribbon.  The  kapok  fiber,  on  the  other  hand,  appears  as  a  round,  smooth 
fiber,  having  in  a  marked  degree  a  very  distinct  luster.  Upon  close  observa- 
tion this  fiber  is  seen  to  have  a  very  thin  cell-wall,  and  to  be  almost  entirely 
free  from  twists.  There  appear,  however,  at  times,  what  seem  to  be 
joints  or  nodules.  As  a  rule  the  contents  of  the  cells  are  very  indistinct, 
differing  greatly  from  cotton  in  this  respect. 

Chemically,  there  is  no  test  that  will  serve  to  distinguish  these  two 
fibers  that  can  be  applied  and  concluded  rapidly,  for  the  reason  that  both 


IDENTIFICATION   OF   ARTIFICIAL  SILKS  933 

are  nearly  pure  cellulose,  and  respond  in  a  very  similar  manner  to  the 
same  reagents.  It  is  quite  possible  to  distinguish  between  cotton  and 
kapok  by  the  use  of  a  1  percent  solution  of  aniline  sulfate  (about  4.5  grains 
of  aniline  sulfate  in  1  oz.  of  water).  If  a  small  quantity  of  kapok  is 
moistened  with  a  few  drops  of  this  solution  it  will  in  a  short  time  assume  a 
distinct  yellow  color,  which  will  not  appear  when  cotton  is  subjected  to  the 
same  reagent.  This  is  due  to  the  fact  that  the  kapok  fiber  contains  a 
trace  of  lignified  tissue,  which  reacts  yellow  with  aniline  sulfate.  This 
test  can  be  conveniently  made  in  a  white  china  dish. 

Kapok  gives  a  reddish  violet  coloration  with  phloroglucinol  and 
hydrochloric  acid,  whereas  cotton  furnishes  only  a  faint  violet  coloration 
with  this  reagent. 

Greshoff,^  gives  the  following  tests  to  distinguish  between  cotton 
and  kapok:  (a)  zinc  chloride  and  iodine  solution  gives  a  violet-blue 
coloration  with  cotton,  but  a  yellow  color  with  kapok;  (6)  by  immersing 
the  fibers  for  one  hour  in  an  alcoholic  solution  of  Magenta  (0.01  gram  of 
Magenta  in  30  cc.  of  alcohol  and  30  cc.  of  water)  cotton  remains  practically 
colorless,  whereas  kapok  is  dyed  a  bright  red.  A  further  test  is  with 
Schweitzer's  reagent;  this  causes  cotton  to  swell  up  and  dissolve,  while 
kapok  is  not  affected.  Greshoff  claims  that  a  quantitative  estimation  of 
cotton  in  kapok  may  be  made  by  distillation  of  the  material  with  hydro- 
chloric acid  and  precipitation  of  the  liberated  furfural  by  phloroglucinol. 
Kapok  contains  23  to  25  percent  of  pentosans  (furfural  yielding  bodies) 
while  cotton  only  has  about  3  percent. 

Another  simple  test  is  to  immerse  the  samples  for  a  few  minutes  in  a 
chlorine  solution  and  then  squeeze  out  the  surplus  liquor.  Place  the 
sample  in  a  saucer  and  pour  on  it  a  small  quantity  of  ammonia.  The 
cotton  remains  white  and  the  kapok  will  become  a  reddish  shade.  In 
place  of  the  chlorine  solution,  hypochlorite  or  chloride  of  lime  can  be 
used.  The  reddish  shade  of  the  kapok  is  characteristic,  but  does  not 
remain  on  the  fiber. 

Still  another  method  is  to  immerse  the  fiber  in  nitric  acid  for  one 
minute,  then  rinse  in  water  and  immerse  in  ammonia.  The  cotton  remains 
white  and  the  kapok  becomes  yellow.  Like  the  reddish  shade  with  the 
last-mentioned  test,  the  yellow  color  does  not  remain  on  the  kapok. 

12.  Identification  of  Artificial  Silks.— In  Table  IX  are  given  Hassac's 
tests  to  identify  the  different  varieties  of  artificial  silks  or  forms  of  lustra- 
cellulose,  and  also  the  distinction  between  these  latter  and  true  silk. 
The  reagents  given  in  this  table  are  prepared  as  follows : 

(a)  Glycerol-sulfuric  acid:   10  cc.  glycerol,  5  cc.  water,  15  cc.  cone,  sulfuric  acid. 

(b)  Potassium-iodo-iodide,  0.3  gram  potassium  iodide,  30  cc.  water,  and  iodine 
in  excess. 

1  Chem.  Central,  1908,  p.  647. 


934 


ANALYSIS  OF  TEXTILE  FABRICS  AND  YARNS 


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936  ANALYSIS   OF  TEXTILE   FABRICS  AND   YARNS 

(c)  Zinc-chloro-iodide:  1.75  grams;  zinc  chloride,  30  cc.  water;  and  iodine  to 
saturation . 

(d)  Concentrated  sulfuric  acid. 

(e)  Chromic  acid  in  half-saturated  solution. 
(/)    Caustic  potash  in  45  percent  solution. 

{g)  Ammoniacal  solution  of  copper  oxide  prepared  by  dissolving  oxide  of  copper 
in  ammonia  water  to  the  point  of  saturation,  and  there  passing  through  it  a  current  of 
air  freed  from  carbonic  acid  by  a  preliminary  passage  through  a  solution  of  caustic 
potash. 

{h)  Amjnoniacal  solution  of  nickel  oxide  prepared  by  dissolving  2  grams  crystallised 
nickel  sulfate  in  30  cc.  water,  precipitating  the  nickel  with  caustic  soda,  filtering  and 
redissolving  the  precipitate  in  ammonia  water. 

(i)  Alkaline-glycerol  solution  of  copper  prepared  by  dissolving  3  grams  copper 
sulfate  in  30  cc.  water  and  1.75  grams  glycerol,  then  adding  sufficient  caustic  potash 
solution  to  just  redissolve  the  copper  hydrate  at  first  precipitated. 

(j)  Acid  solution  of  diphenylamine  containing  1.57  grams  diphenylamine  and 
25  cc.  concentrated  sulfuric  acid. 

The  determinations  should  be  checked  by  comparative  tests  on  known 
types.  If  samples  are  dyed,  the  color  should  first  be  stripped  by  treatment 
with  hydrosulfite,  but  care  must  be  had  in  such  cases  as  this  treatment 
is  likely  to  vitiate  the  reliability  of  certain  of  the  reactions. 

Collodion  silk  may  be  distinguished  from  viscose  and  cuprammonium 
silks  by  the  fact  that  it  will  always  contain  at  least  a  trace  of  nitrogen 
compound  capable  of  giving  the  blue  diphenylamine  test  and  the  red 
brucine  test.  According  to  Schwalbe  collodion  silk  always  contains  a 
small  amount  of  oxycellulose  produced  during  the  nitration  process,  and 
hence  may  be  distinguished  from  other  cellulose  silks  by  the  fact  that  this 
oxycellulose  will  cause  a  reduction  of  Fehling's  solution.  The  test  is 
made  by  heating  0.2  gm.  of  the  artificial  silk  with  2  cc.  of  Fehling's  solu- 
tion, when  a  green  color  is  obtained  with  collodion  silk,  while  with  viscose 
or  cuprammonium  silk  the  liquid  remains  blue.  Schwalbe  also  recom- 
mends the  use  of  a  solution  of  20  grams  of  zinc  chloride,  2  grams  of 
potassium  iodide,  and  0.1  gram  iodine  in  15  cc.  of  water  as  a  reagent  to 
distinguish  viscose  silk  from  cuprammonium  silk.  When  equal  quanti- 
ties of  the  two  silks  are  treated  with  this  reagent  and  then  washed  with 
water,  the  viscose  silk  remains  bluish  green  for  some  time,  whereas  the 
cuprammonium  silk  soon  loses  its  brown  color.  This  test,  however,  is 
not  satisfactory,  as  it  is  difficult  to  obtain  the  proper  color  reactions. 

Maschner  ^  finds  that  even  after  considerable  practice  a  microscopical 
examination  is  not  a  reliable  means  of  distinguishing  between  different 
kinds  of  artificial  silks.  The  most  important  chemical  tests  are  the 
diphenylamine  reaction  recommended  b\  Siivern  for  the  detection  of  col- 
lodion silks,  Schwalbe's  reduction  test  with  Fehling  solution,  for  the  same 
purpose,  and  the  latter's  test  with  a  solution  of  zinc  chlor-iodine  to  distin- 
guish between  cuprate  and  viscose  silks.      Maschner  concluded  that  of 

^  Farber.  Zeit.,  1910,  p.  352. 


DISTINCTION   BETWEEN   TRUE   SILK   AND  WILD  SILK  937 

these  three  reactions  only  the  first  is  at  all  reliable  as  the  other  two  give  dif- 
ferent results  with  even  artificial  silks  of  the  same  class.  For  the  same  rea- 
son the  behavior  of  artificial  silks  toward  dyestuff  solutions  is  not  a  satis- 
factory method  of  distinction.  A  means  to  distinguish  between  the  silks, 
however,  is  afforded  by  the  action  of  concentrated  sulfuric  acid.  The 
test  is  as  follows:  0.2  gram  of  the  silk  to  be  examined  together  with  an 
equal  quantity  of  a  standard  artificial  silk  of  known  make  are  put  in  small 
dry  Erlenmeyer  flasks  which  stand  on  white  paper  and  about  10  cc.  of 
pure  sulfuric  acid  are  poured  over  them.  The  flasks  are  shaken  to 
moisten  thoroughly  the  fibers  and  the  immediate  effect  of  the  acid  is 
observed.  The  flasks  are  then  kept  under  observation  for  about  l| 
hours.  Collodion  silk  remains  at  first  quite  colorless  and  only  after 
40-60  minutes  does  the  liquor  assume  a  weak  yellowish  tone.  Cuprate 
silk  at  once  takes  on  a  yellow  or  yellowish  brown  tone  and  the  liquor 
becomes  yellowish  brown  after  40-60  minutes.  Viscose  silk  is  at  once 
turned  reddish  brown  by  the  acid  and  the  liquor  after  40-60  minutes 
becomes  a  rusty  brown  color. 

Collodion  silk  may  be  distinguished  (though  not  in  a  very  satisfactory 
manner)  from  viscose  and  cuprammonium  silks  by  the  microscopic  appear- 
ance in  polarised  light. 

Herzog,  in  Table  X,  gives  the  microscopical  characteristics  of  arti- 
ficial silks. 

According  to  Beltzer  a  solution  of  Ruthenium  Red  (0.01  gram  in  10  cc. 
of  water)  is  a  useful  microchemical  stain  for  the  identification  of  artificial 
silks.  Collodion  silk  is  stained  a  deep  red  with  this  reagent,  cuprate  silk 
is  scarcely  tinted,  while  viscose  silk  is  colored  a  deep  pink.  Artificial 
silks,  however,  which  have  been  treated  with  formaldehyde  (for  increasing 
their  resistance  to  water)  are  not  stained  by  Ruthenium  Red  solution. 

13.  Distinction  between  True  Silk  and  Different  Varieties  of  Wild 
Silk. — True  silk  (from  Bomhyx  mori)  rapidly  dissolves  (one-half  minute) 
in  boiling  concentrated  hydrochloric  acid;  Senegal  silk  (from  Faidherbia) 
dissolves  in  a  somewhat  longer  time,  while  yama-mai,  tussah,  and  cynthia 
silks  require  a  much  longer  time  for  complete  solution.  True  silk  is  also 
rather  easily  soluble  in  strong  caustic  potash  solution,  whereas  the  other 
varieties  of  silk  are  not.  Silbermann  ^  states  that  true  silk  may  be 
distinguished  from  tussah  silk  by  treatment  with  a  semi-saturated  solu- 
tion of  chromic  acid,  prepared  by  dissolving  chromic  acid  in  cold  water 
to  the  point  of  saturation  and  then  adding  an  equal  volume  of  water. 
True  silk  is  said  to  be  completely  dissolved  on  boiling  in  this  solution 
for  one  minute,  whereas  wild  silk  remains  insoluble.  Chittick,  however, 
on  testing  this  method  out  has  found  that  tussah  silk  will  also  dissolve 
under  these  conditions,  and  that  the  method  cannot  be  employed  to 
distinguish  between  the  two  varieties  of  silk.     This  chromic  acid  method 

^  Die  Seide,\ol.2,i>. 206. 


938 


ANALYSIS   OF  TEXTILE  FABRICS  AND   YARNS 


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DISTINCTION   BETWEEN   TRUE  SILK  AND   WILD  SILK 


939 


of  separation  is  to  be  found  generally  quoted  in  the  literature  of  silk 
technology  and  has  evidently  crept  into  the  authorities  without  being 
properly  tested  out. 

Suvern   gives   the   following   table   showing   the   principal   points   of 
difference  between  ordinary  silk,  tussah  silk,  and  artificial  silk: 


Artificial 

Reagent. 

Chinese  Raw 
Silk. 

Tussah  Silk. 

(Chardonnet) 
Silk. 

Potassium  hydroxide  solu- 

Dissolves on  gently 

Dissolves  on  boil- 

Unaltered 

tion,  concentrated 

warming 

ing 

Potassium     hydroxide,     40 

Acted  on  at  65°  C. 

Swells  up  at  75°. 

Insoluble 

percent  solution 

Dissolved   at   85° 

Dissolves     at 

C. 

120°  C. 

Zinc    chloride,    60   percent 

Completely    dis- 

Completely   dis- 

Dissolves  at   140° 

solution 

solved  at  120°  C. 

dissolved    at 
135°  C. 

to  145°  C. 

Copper    sulfate     ammonia 

Dissolves  in  30  min- 

Scarcely attacked 

Not  attacked  even 

solution       (CUSO4,       10 

utes    at    ordinary 

on  boiling 

grms.;    glycerol,   10  cc; 

temperature 

40  percent  NH3,  10  cc.) 

Cuprammonium  solution 

Dissolves   with   ex- 

Unattacked 

Unattacked     even 

ception    of    slimy 

on  boihng 

residue 

FehUng's  solution 

Dissolves  readily  on 

Dissolves  on  boil- 

Not attacked 

boiling 

ing 

Millon's  reagent 

Violet  coloration  on 

Violet    coloration 

No  change 

boiling 

on  boiMng 

Iodine  solution 

Deep  brown  colora- 

Faint brown  col- 

Brown    coloration 

tion 

oration 

changing  to  blue 

Ash,  percent 

0.95 

1.15 

1.60 

Behavior  at  200°  C,  and 

Becomes  brown  and 

Scarcely    altered; 

Blue-black  colora- 

loss in  weight 

friable;   11.15  per- 

11.21 percent 

tion  then  carbon- 

cent 

ization  .     Friable 
with   difficulty; 
43  to  65  percent 

Percentage  of  nitrogen 

16.60 

16.79 

0.15 

Percentage  of  water 

7.99 

8.26 

10.37 

Water  absorbed  in  48  hours, 

percent 

2.24 

5.00 

5.24 

Under  the  microscope  true  silk  can  readily  be  told  from  wild  silks, 
as  the  latter  fibers  are  broad  and  flat,  and  show  very  distinct  longitudinal 
striations,  which  are  absent  in  true  silk.  Exception  must  perhaps  be 
made  with  the  wild  silk  from  Saturnia  spini,  which  can  scarcely  be  told 
from  true  silk  by  a  microscopical  examination.  With  regard  to  distin- 
guishing between  the  different  varieties  of  wild  silks  themselves,  some 
valuable  information  may  be  gained  by  a  determination  of  their  relative 


940  ANALYSIS   OF   TEXTILE   FABRICS   AND  YANRS 

diameters.     Hohnel  gives  the  following  values  for  the  greatest  thickness 
of  the  different  silks:  ^I,^^^^^^ 

True  silk  {Bombyx  mori) 20  to  25 

Senegal  silk        (Faidherhia  bauhini) 30  to  35 

Ailanthus  silk    (Aitacus  cynthia) 40  to  50 

Yama-mai  silk  {Anlhercea  yama-rnai) 40  to  50 

Tussah  silk        {Bombyx  selene) 50  to  55 

Tussah  silk        {Bombyx  rnyUtla) 60  to  65 

According  to  Wiesner  and  Prasch,  the  breadths  of  the  single  fibers  of 

different  silks  are  as  follows:  ,,■ 

Microns. 

Ailanthus  silk 7  to  27,  mostly  14 

Yama-mai  silk 10  to  45,  mostly  23 

Bombyx  mylitia 14  to  75,  mostly  42 

Bombyx  selene 27  to  41,  mostly  34 

Senegal  silk 12  to  34,  mostly  22 

True  silk 9  to  21,  mostly  13 

True  silk,  ailanthus  silk,  and  Senegal  silk  do  not  show  any  cross- 
marks,  or  only  veiy  faint  indications  of  such;  whereas  with  tussah  silk 
and  yama-mai  silk  the  cross-marks  are  very  distinct  and  characteristic. 

The  microscopical  appearance  of  the  end  of  the  fiber  on  being  torn 
apart  also  serves  at  times  as  a  useful  means  of  distinguishing  the  variety 
of  silk;  true  silk,  tussah  silk,  and  yama-mai  silk  show  scarcely  any  fraying 
at  the  ends;  in  Senegal  silk  the  fraying  is  very  noticeable  in  almost  every 
fiber;  while  in  ailanthus  silk  about  one-half  of  the  number  of  fibers  show  a 
frayed  end. 

14.  Wild  Silks  of  Minor  Importance. — Besides  the  wild  silks  here 
mentioned,  there  are  a  few  others  of  lesser  importance,  which  for  the  sake 
of  completeness  are  herewith  described. 

1.  Salurnia  polyphetmis,  a  North  American  variety,  consists  of  very  flat  fibers,  with 
large  air-canals  and  numerous  structural  filaments  sejiarating  at  the  edge  of  the  fiber; 
coarse  lumps  of  adhering  sericine  are  frequent;  well-defined  cross-marks  are  also  fre- 
quent. The  single  fiber  is  about  33  microns  in  width;  in  its  polariscopic  appearance 
these  fibers  very  much  resemble  ailanthus  silk. 

2.  Arryndia  ricini,  the  fibers  are  even  more  flattened  than  the  preceding  and 
resemble  a  thin  band  or  ribbon;  large  air-canals  are  of  frequent  occurrence;  striations 
very  apparent;  the  sericine  layer  is  in  places  very  thin,  and  sometimes  apparently 
lacking  altogether.  The  double  fiber  is  about  45  to  55  microns  in  width,  and  4  to 
6  microns  thick.  At  the  edge  of  the  fiber  frayed  ends  of  structural  filaments  are  often 
apparent.  Cross-marks  are  rather  ill-defined,  but  of  frequent  occurrence.  The 
sericin  layer,  though  thin,  is  quite  uniformly  developed. 

3.  Anthcrcca  pernyi  has  a  very  fiat  fiber,  resembling  a  ribbon;  it  does  not  fray  out 
at  the  ends,  and  shows  scarcely  any  single  filaments.  The  double  fiber  measures  60 
to  80  microns  in  width  and  8  to  10  microns  in  thickness.  Cross-marks  are  rather  few 
and  indistinct.  The  sericine  layer  is  very  thin,  and  in  general  hardly  noticeable. 
Moderately  sized  air-canals  are  present. 

4.  Satumia  cecrojna  is  to  be  found  in  Texas.  The  fiber  is  also  flat  and  ribbon-like 
in  form;    the  double  fiber  measures  60  to  90  microns  in  width  and  10  to  15  microns 


APPEARANCE  OF  SILKS  UNDER  POLARISCOPE  941 

in  thickness;  air-canals  are  frequent  and  large,  hence  the  fiber  usually  appears  rather 
dark  under  the  microscope.  The  cross-marks  are  very  distinct,  and  at  such  points 
the  fiber  is  much  broader.  The  fiber  is  usually  much  frayed  out  and  individual 
filaments  are  easily- distinguished.  The  sericine  layer  is  quite  thin,  but  very  uniform. 
5.  Altacus  lanula  has  fibers  which  are  not  so  flat  as  the  preceding.  The  double 
fiber  is  25  to  35  microns  in  width  and  12  to  18  microns  in  thickness.  The  air-canals 
are  fine  and  delicate;  and  the  fiber  shows  but  a  slight  degree  of  fraying.  The  sericine 
layer  is  very  thin  and  finely  granulated  on  the  surface;  in  places  it  has  the  form  of 
irregular  shreds.  The  fiber  as  a  whole  has  a  brownish  yellow  appearance,  due  to  the 
ochre-yellow  color  of  the  sericine  layer. 

15.  Appearance  of  Silks  under  Polariscope. — By  the  use  of  the  polaris- 
copic  attachment  to  the  microscope,  considerable  differences  can  be 
observed  in  the  interference  colors  displayed  by  the  different  varieties  of 
silks.  It  is  best  to  conduct  these  observations  under  a  magnification  of 
30  to  50  diameters;  and  as  the  silk  fibers  are  more  or  less  ovoid  in  section, 
it  must  be  borne  in  mind  that  the  same  fiber  will  give  a  different  color 
phenomenon,  depending  on  whether  it  is  viewed  from  the  narrow  side 
or  from  the  broad  side.  Hence,  to  obtain  trustworthy  results,  the  appear- 
ance of  the  same  side  only  of  the  fibers  should  be  compared.  Also,  the 
appearance  of  single  fibers  only,  and  not  of  crossed  fibers,  should  be  taken. 
Hohnel  gives  the  following  description  of  the  appearance  of  the  different 
silk  fibers  viewed  in  polarised  light,  the  observations  being  made  with  a 
dark  field,  and  under  a  magnification  of  30  to  50  diameters: 

1.  True  silk:  (a)  broad  side,  very  lustrous,  of  a  bluish  or  yellowish  opalescent  white; 
the  same  color  is  nearly  always  to  be  found  over  the  entire  breadth;  (6)  narrow  side, 
exactly  similar  to  the  preceding. 

2.  Yama-viai  silk:  (a)  broad  side,  generally  of  a  pure  bluish  opalescent  white;  also 
darker  bluish  to  almost  black  tones;  nearly  all  of  the  colors  are  brilliant;  (6)  narrow 
side,  shows  all  colors,  very  brilliant  and  contrasted;  darker  and  blackish  tones  also  occur. 

3.  Tussah  silk  (from  Bombyx  selene):  (a)  broad  side,  shows  all  colors,  very  brilliant; 
thickness  of  the  fiber  very  uneven,  hence  the  colors  change  through  the  length;  the 
thick  parts  are  dark  blue  and  reddish  violet,  while  the  thinner  parts  are  yellow  or 
orange;  (b)  narrow  side,  shows  bright  red  and  bright  green  colors,  though  often  but 
slightly  visible;   the  colors  form  long  flecks;   often  only  dark  gray  to  black. 

4.  Tussah  silk  (from  Bombyx  mylitta):  (a)  broad  side,  a  bluish  opalescent  white 
prevailing;  also  brown,  gray,  and  black  tones;  the  colors  occur  in  flecks  like  pre- 
ceding, though  scarcely  even  darker  blue,  but  mostly  bright  orange  to  red  or  brown; 
(6)  narrow  side,  color  a  dull  gray  with  bright  red  or  gnien  flecks;  the  general  appear- 
ance is  very  similar  to  the  preceding  silk. 

5.  Ailanthus  silk:  (a)  broad  side,  bright  yellow  or  yellow-brown  to  gray-brown 
colors;  (b)  narrow  side,  nearly  all  colors,  but  rather  soft,  and  not  very  contrasted, 
seldom  very  bright,  but  rather  dull;   short  flecks  of  green,  yellow,  violet,  red,  or  blue. 

6.  Senegal  silk:  (a)  broad  side,  bright  yellowish  white,  gray  to  brown,  seldom  bluish 
white  in  color;  (b)  narrow  side,  faint  and  dull  gray,  brown  to  blackish  colors,  seldom 
bright  colors. 

Table  XI  presents  the  microscopical  characteristics  of  the  most  im- 
portant varieties  of  natural  silk.^ 

1  Herzog,  Die  Unterscheidung  der  natilrlichen  und  kunstlichen  Seiden,  p.  14. 


942 


ANALYSIS   OF   TEXTILE   FABRICS   AND   YARNS 


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\ 

CHAPTER  XXVII 
TESTING  OF  TEXTILE  FABRICS 

1.  Conditioning  of  Textiles. — In  speaking  of  the  hygroscopic  quahty  of 
wool  and  silk,  it  was  mentioned  that  these  fibers  were  capable  of  absorbing 
a  considerable  amount  of  moisture,  and  that  this  amount  varied  within 
rather  large  limits,  depending  upon  the  conditions  of  temperature  and 
humidity  of  the  air  to  which  it  may  be  exposed.  It  may  be  readily  under- 
stood from  these  facts  that  in  the  buying  and  selling  of  wool  and  silk 
goods  upon  a  basis  of  weight,  the  question  as  to  how  much  moisture  is 
present  becomes  of  great  practical  importance  in  determining  the  money 
value  of  the  operation.  In  England  and  on  the  continent  of  Europe,  this 
fact  has  been  recognised  for  some  time,  and  there  have  been  established 
at  the  various  European  textile  centers  official  laboratories  where  the  per- 
centage of  moisture  in  textile  materials  is  carefully  ascertained,  and  the 
sales  are  based  on  the  actual  amount  of  normal  fiber  contained  in  the  lot 
examined.  These  official  laboratories  are  called  "  conditioning  houses," 
and  the  process  of  determining  the  amount  of  moisture  is  termed 
''  conditioning."  The  first  official  conditioning  house  was  established  at 
Lyons  in  1805  for  the  conditioning  of  silk.  There  are  now  conditioning 
houses  in  several  European  cities,  as  also  in  New  York  and  Philadelphia, 
and  lately  there  has  been  one  established  in  Shanghai. 

In  the  conditioning  of  wool  the  operation  is  carried  out  as  follows: 
Representative  samples  are  taken  from  the  lot  under  examination;  these 
are  mixed  together,  and  three  test  samples  of  |  to  1  lb.  each  are  taken. 
The  test  sample,  after  being  carefully  weighed,  is  placed  in  the  conditioning 
apparatus  and  dried  to  constant  weight  at  a  temperature  of  105°  to 
110°  C.  (220°  F.).  This  weight  represents  the  amount  of  dry  wool  fiber 
present  in  the  sample,  the  loss  in  weight  represents  the  amount  of  moisture 
the  wool  contained. 

The  amount  of  normal  wool  is  obtained  by  adding  to  the  dry  weight 
of  the  wool  the  amc;mt  of  moisture  supposed  to  be  present  in  the  air-dried 
material  under  normal  conditions  of  humidity  and  temperature.  The 
added  amount  is  termed  regain,  and  is  officially  fixed  by  the  conditioning 
house.  This  permissible  percentage  of  regain  varies  with  the  form  of  the 
manufactured  wool;  the  conditioning  house  at  Bradford,  England,  for 
instance,  has  established  the  following  figures: 

943 


944 


TESTING   OF   TEXTILE   FABRICS 


Wools 

Tops  combed  with  oil .  .  . 
Tops  combed  without  oil 

Noils 

Worsted  yarns 


Direct  Loss,  Percent. 


13 

79 

15 

97 

15 

43 

12 

28 

15 

43 

In  the  instructions  issued  by  the  Manchester  Testing  House  the 
removal  of  moisture  from  wool  is  considered  complete  when  the  material 
has  been  heated  for  forty  minutes  at  100°  C.  with  proper  ventilation. 
Woodmansey  ^  studied  the  relative  amounts  of  moisture  removed  from 
wool  in  different  times,  as  follows: 

Percent. 

Loss  on  heating  1  hour 13 .  84 

After  a  further  3  hours 0.21 

"       3  hours 0.12 

"  "       5  hours 0.11 

"  "     10  hours 0.08 

In  these  tests,  however,  the  temperature  was  150°  C.  and  it  is  therefore 
probable  that  more  than  mere  hygroscopic  moisture  was  driven  off. 

The  system  of  conditioning  adopted  at  Bradford  is  as  follows:  The 
weights  of  the  packages  and  conditions  are  taken  by  three  persons  inde- 
pendently on  sensitive  scales  which  are  adjusted  weekly.  These  scales 
have  a  weighing  capacity  from  one-half  pound  to  ten  tons.  In  making 
the  tests  for  moisture,  the  samples  are  carefully  selected  from  various 
parts  of  the  packages.  The  amount  of  the  material  taken  for  this 
purpose  is  for  wools,  noils,  and  wastes,  about  2  lbs.  from  each  package; 
for  tops,  three  balls;  for  yarns  in  hank,  about  4  lbs.  in  1200  lbs;  for  yarns 
on  bobbins  or  tubes,  twenty  to  forty  bobbins  or  tubes,  and  for  yarns  on 
cones,  cheeses,  etc.,  5  to  15  lbs. 

The  standard  regains  and  allowances  are  as  follows: 

Wools  and  waste,  for  moisture,  a  regain  cf  16  percent,  ecjual  to  2  ozs.  3j  drs.  per 
pound. 

Tops  combed  with  oil,  for  moisture,  a  regain  of  19  percent,  equal  to  2  ozs.  9  drs. 
per  pound. 

Tops  combed  without  oil,  for  moisture,  a  regain  of  18 J  percent,  equal  to  2  ozs. 
7^  drs.  per  pound. 

Ordinary  noils,  for  moisture,  a  regain  of  14  percent,  equal  to  1  oz.  15^  drs.  per 
pound.     Clean  noils,  a  regain  of  16  percent,  equal  to  2  ozs.  3j  drs.  per  pound. 

Yarns,  worsted,  for  moisture,  a  regain  of  18i  percent,  equal  to  2  ozs.  7^  drs.  per 
pound. 

Yarns,  cotton,  for  moisture,  a  regain  of  8 J  percent,  equal  to  1  oz.  4  drs.  per  pound. 

'  Jour.  Soc.  Dyers  &  Col,  1918,  p.  227. 


CONDITIONING   OF  TEXTILES 


945 


Yarns,  silk,  for  moisture,  a  regain  of  11  percent,  equal  to  1  oz.  9j  drs.  per  pound. 
Cloths,  worsted  and  woolen,  a  regain  of  16  percent,  equal  to  2  ozs.  3j  drs.  per  pound. 

The   conditioning  house  at  Roubaix,   on  the  Continent,   allows  the 
following  percentages  for  regain  on  woolen  materials: 

Percent. 

Wools 14^ 

Tops 18^ 

Woolen  yarns 17 

The  percentage  of  regain  allowed  at  Bradford  is  considerably  higher 
than  that  which  would  be  allowed  at  most  American  textile  centers. 

100 


90 


80 


70 


»  60 


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10  15  20 

Moisture  for  100  parts  of  Dry  Material 


25 


Fig.  403. — Effect  of  Humidity  on  Hygroscopic  Quality  of  Fibers.     (Schloesing.) 

The  author  has  found  from  many  conditioning  tests  at  Philadelphia  that 
woolen  yarns  will  average  about  10  percent  of  moisture,  worsted  tops 
(in  the  oil)  and  loose  wool  about  12  percent,  and  woven  fabrics  of  wool 
about  8  to  9  percent.     This  would  correspond  to  a  regain  on  the  dry 

weight  as  follows: 

Percent. 

Woolen  yarns 11.1 

Worsted  tops  and  loose  wool 13 . 6 

Woolen  cloth 9.9 

In  order  to  give  fair  regains  for  commercial  purposes,  the  author  would 
recommend  for  woolen  yarns  a  regain  of  12  percent;  for  tops  and  roving 
and  loose  wool,  15  percent;  and  for  wool  cloth,  11  percent.  For  silk  the 
regain  allowed  should  be  11  percent,  and  for  cotton  and  vegetable  fibers 
in  general  the  regain  should  be  8  percent. 

In  the  United  States  Government  specifications  for  army  blankets,  etc., 
of  wool,  a  regain  of  11  percent  is  allowed. 


946 


TESTING   OF   TEXTILE   FABRICS 


Hartshorne  gives  the  following  table  showing  the  regains  of  worsted 
yarns  for  various  temperatures  and  percentages  of  humidity: 

TABLE    OF    WORSTED    REGAIN    FOR    VARIOUS    TEMPERATURES    AND 
PERCENTAGES  OF  HUMIDITY 


Percentage 

Degrees  Fahrenheit. 

Humidity. 

50. 

60. 

70. 

80. 

90. 

100. 

40 

12.8 

12.4 

12.0 

11.5 

10.9 

10.4 

50 

14.7 

14.3 

13.8 

13.2 

12.6 

12.1 

60 

16.7 

16.1 

15.6 

14.9 

14.4 

13.8 

70 

18.7 

18.0 

17.4 

16.8 

16.2 

15.6 

80 

20.9 

20.2 

19.4 

18.7 

18.2 

17.7 

90 

23.5 

22.7 

21.8 

21.1 

20.9 

20.8 

100 

27.1 

26.2 

25.4 

24.8 

24.7 

24.6 

100 
90 

80 

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Moisture  for  100  parts  of  Dry  Material 


30 


Fig.  404. 


-Effect  of  Humidity  on  Hygroscopic  QuaHty  of  Different  Varieties  of  Cotton 
and  Silk.     (Schloesing.) 


Schloesing  has  plotted  curves  (Figs.  403  and  404)  showing  the  relation 
between  the  humidity  of  the  air  and  the  moisture  contained  in  air-dry 
textile  materials. 

Scheurer  ^  conducted  experiments  to  ascertain  the  amount  of  water 
fixed  by  various  fibers  at  100°  C.  in  an  atmosphere  saturated  with  steam; 
his  results  were  as  follows: 


^BuU.  Soc.  Ind.  Mulh.,  1900,  February. 


CONDITIONING  OF   TEXTILES 


947 


Fiber,  Water  Fixed, 

Previously  Dried  at  100°  C.  Percent. 

Bleached  white  cotton 23 . 0 

Unbleached  linen 27 . 7 

•  Unbleached  jute 28 . 4 

Bleached  silk 36 . 5 

Bleached  and  mordanted  wool 50 . 0 

According  to  Scheurer,  these  figures  show  that  for  the  textile  fibers 
there  exists  a  fixed  capacity  of  saturation  which  remains  perfectly  constant 
in  the  same  atmosphere  of  steam,  as  soon  as  the  equilibrium  is  once 
established. 

The  International  Congress  at  Turin  (1875)  fixed  the  amount  of 
"  regain  "  for  different  textile  fibers  as  follows: 

Percent . 

Silk 11 

Wool  (tops) 18i 

Wool  (yarn) 17 

Cotton 8^ 

Linen 12 

Hemp 12 

Jute 13f 

New  Zealand  hemp 13f 

The  adoption  of  18.25  percent  regain  as  the  legal  standard  in  France, 
according  to  Persoz  ^  has  led  to  the  practice  of  worsted  tops  being  exces- 
sively moistened  before  sale  to  the  spinner.  He  recommends  a  reversion 
to  the  old  standard,  as  he  considers  that  13  percent  is  the  average  amount 
of  moisture  in  wool,  and  hence  the  weight  for  normal  moisture  should  be 
found  by  adding  15  percent  to  the  dry  weight. 

The  following  table  shows  the  amount  of  moisture  taken  up  by  various 
fibers  under  different  conditions  of  humidity  and  at  a  temperature  of  75°  F. 


Percent, 

Percent  Moisture. 

Percent, 

Percent  Moisture. 

Relative 

Relative 

Humidity. 

Cotton. 

Silk. 

Wool. 

Humidity. 

Cotton . 

Silk. 

Wool. 

5 

1.4 

1.8 

2.2 

55 

6.3 

9.4 

13.4 

10 

2.4 

3.2 

4.0 

60 

6.7 

9.9 

14.2 

15 

3.0 

4.4 

5.7 

65 

7.3 

10.5 

15.0 

20 

3.6 

5.4 

7.1 

70 

7.9 

11.4 

16.0 

25 

3.9 

6.1 

8.3 

75 

8.8 

12.5 

17.1 

30 

4.3 

6.7 

9.4 

80 

9.9 

14.0 

18.6 

35 

4.6 

7.3 

10.4 

85 

11.4 

15.9 

20.5 

40 

5.0 

7.8 

11.0 

90 

13.6 

18.4 

23.2 

45 

5.3 

8.4 

11.8 

95 

17.5 

22.7 

27.0 

50 

5.7 

8.8 

12.6 

• 

» Rev.  Gen.  Mat.  Col.,  1900,  p.  81. 


948 


TESTING  OF  TEXTILE  FABRICS 


Lewis,  of  the  National  Bureau  of  Standards,  has  shown  that  the 
thtual  regain  in  worsted  tops  varies  with  different  relative  humidities  of 
ace  air,  the  average  for  different  grades  of  wool  being  as  follows  (at  70°  F.) : 

Relative  ^^^^^^ 

Humidity,  Percent. 

Percent. 

45 13 .  33 

55''!!" 14.51 

65 15.37 

75 16.38 

85 18.92 

It  will  be  noticed  that  above  75  percent  relative  humidity  the  increase  in 
regain  is  very  marked.  This  Bureau  has  also  made  tests  on  the  influence 
of  varying  humidity  on  the  strength  and  count  of  worsted  yarns.  The 
following  table  shows  the  results  of  a  large  number  of  tests  on  different 
yarns  (single  and  two-ply) : 


Tensile  Strength  at  Different  Humidity 

Rel^ti^e  Tensile 

Humidity  Strength, 

^t  70°  F.,  Grams. 

Percent. 

45 234 

55 231 

65 220 

75 216 

85 191 

It  will  be  noted  that  as  the  relative  humidity  increases  the  tensile  strength 
of  the  worsted  yarn  decreases. 

The  influence  of  variation  in  the  relative  humidity  in  the  yarn  count 
and  yardage  of  worsted  yarns  is  shown  in  the  following  tables  (at  70°  F.) : 


Yarn  Counts  at  Relative 
Humidity  of 

Difference  Between 

Difference  Between 

Difference  Between 

95%  and  65% 

65%  and  85% 

45%  and  85% 

Yarn. 

Relative 

Humidity. 

Relative 

Humidity. 

Relative 

Humidity. 

45%. 

65%. 

85%. 

Count. 

Yardage 
per  Lb. 

Count. 

Yardage 
per  Lb. 

Count. 

Yardage 
per  Lb. 

20,  1 

20.2.5 

19.77 

18.82 

0.48 

269 

0.95 

532 

1.43 

801 

24/1 

24.58 

23.97 

22.79 

0.61 

342 

1.18 

661 

1.79 

1002 

24/1 

25.51 

24.94 

23.80 

0  57 

319 

1.14 

638 

1.71 

958 

3fi/l 

34.49 

33.68 

81.77 

0.81 

4.54 

1.91 

1070 

2.72 

1523 

38/1 

35.47 

34.71 

32 . 8.5 

0.76 

426 

1.86 

1042 

2.62 

1467 

40/1 

39.09 

38.08 

36.03 

1.01 

566 

2.05 

1148 

3.06 

1714 

28/2 

27.74/2 

27.18/2 

25.68/2 

0.56 

314 

1.50 

840 

2.06 

1154 

36/2 

34 . 28/2 

33 . 66/2 

31.80/2 

0.62 

347 

1.86 

1042 

2.48 

1389 

APPARATUS   FOR  CONDITIONING 


949 


The  method  of  calculating  the  amount  of  normal  wool  may  be  illustrated  by  the 
following  example:  A  lot  of  1000  lbs.  of  loose  wool  was  submitted  for  conditioning; 
ten  samples  of  1  lb.  each  were  taken  from  different  parts  of  the  lot;  these  were  mixed 
together  and  three  samples  of  250  grams  each  were  taken  for  testing.  On  drying  to 
constant  weight  the  three  samples  lost,  respectively,  (1)  12.25  percent,  (2)  12.30 
percent,  (3)  12.22  percent,  making  the  loss  12.26  percent.  Hence  in  the  entire  lot 
of  1000  lbs.  of  wool  there  were  122.6  lbs.  of  moisture  or  1000-122.6  =  877.4  lbs.  of 
dry  wool.     The  permissible  amount  of  regain  in  this  case  was  15  percent;    hence  the 

amount  of  normal  wool  would  be  f  877.4  X  ) [-877.4  =  1009  lbs.  instead  of  1000  lbs. 

2.  Apparatus  for  Conditioning. — The  apparatus  employed  for  the 
conditioning  test  is  usually  one  of  such  a  construction  as  to  be  especially 
adapted  for  the  purpose.  The  form 
may  differ  somewhat  in  details  with 
different  makers,  but  a  typical  con- 
ditioning oven  may  be  described 
as  follows : 

The  apparatus  consists  of  an 
upright  oven  heated  by  a  flame 
placed  in  the  lower  chamber.  An 
even  temperature  is  maintained  by 
so  conducting  the  currents  of  heated 
air  that  they  pass  completely  around 
the  inner  chamber  or  oven  contain- 
ing the  sample  to  be  tested  (see  Fig. 
405).  A  thermometer  projecting  into 
the  oven  from  above  is  employed 
for  indicating  the  temperature,  and 
this  may  be  maintained  at  the 
desired  point  by  a  proper  regulation 
of  the  supply  of  heat.  The  material 
to  be  conditioned,  in  whatever  form 
(as  loose  wool,  yarn,  etc.)  is  placed 
in  a  wire  basket  suspended  from  one 
arm  of  a  balance  fixed  outside  and 
above  the  oven;  the  weight  of  the 
basket  and  its  contents  is  counter- 
poised by  placing  definite  weights  on 
a  scale-pan  suspended  from  the  other 
arm  of  the  balance.  As  the  material  diminishes  in  weight  through  the 
volatilisation  of  its  moisture,  the  loss  is  noticed  from  time  to  time  by 
removing  the  necessary  weights  from  the  scale-pan  in  order  to  restore 
the  equilibrium  of  the  balance.  When  the  weight  becomes  constant 
after  heating  at  110°  C,  the  total  loss  is  recorded,  and  this  figure  repre- 


FiG.  405. — Conditioning  Apparatus. 


950 


TESTING  OF  TEXTILE   FABRICS 


sents  the  amount  of  moisture  which  was  originally  present  in  the  material 
tested.  The  balance  is  usually  enclosed  in  a  suitable  case  in  order  to 
protect  it  from  draughts  of  air  whereby  its  sensibility  would  be  impaired. 
Better   control   in   conditioning  may  be  obtained   by   using  electrically 

heated  apparatus  (Fig.  406) 
and  most  modern  condi- 
tioning laboratories  at  the 
present  time  are  equipped 
with  this  form  of  oven. 

The  Wilson  conditioning 
apparatus  (shown  in  Fig. 
407)  is  a  form  used  in  Eng- 
land. It  is  a  gas-heated 
oven  and  is  provided  with 
accessory  apparatus  consist- 
ing of  two  fans,  one  for 
blowing  fresh  air  in,  and 
the  other  for  removing  the 
moist  air.  A  reheater  is 
also  provided  for  using  up 
the  waste  heat  from  the 
oven. 

Another  modern  Ameri- 
can type  is  the  Freas  condi- 
tioning oven  (Fig.  408). 
This  oven  is  electrically 
heated  and  is  provided  with 
a  special  type  of  thermo- 
static control  so  that  the 
temperature  may  be  accu- 
rately maintained  at  any 
desired  degree.  The  oven 
itseK  is  also  provided  with 
ten  baskets  suspended  from 
a  movable  frame  which  may 
be  rotated  as  desired  so 
that  any  of  the  baskets 
may  be  brought  on  to  the  weighing  rod  without  being  removed  from  the 
oven.  This  arrangement  permits  of  making  accurate  tests  at  constant 
temperatures  without  exposure  of  the  samples  to  the  outside  air,  and 
thereby  eliminates  very  materially  the  chances  of  error  due  to  the  sample 
taking  up  moisture  during  the  weighing.  The  oven  is  also  provided  with 
convenient  observation    windows    and    a   low-speed   motor   providing  a 


Fig.  406.— Electrically  Heated  Conditioning 
Apparatus. 


CALCULATIONS  INVOLVED  IN  CONDITIONING 


951 


Fig.  407. — Wilson  Conditioning  Apparatus. 


forced  circulation  of  the  heated  air  which 
rapidly  removes  the  moisture  and  pre- 
vents the  material  from  being  "stewed" 
in  its  own  moisture.  The  chain  move- 
ment permitting  the  baskets  being 
moved,  changed  and  weighed  is  also 
controlled  from  the  outside. 

3.  Calculations  Involved  in  Con- 
ditioning.— In  the  conditioning  of  wool 
(or  of  anj^  other  textile  material),  there 
are  certain  calculations  necessary  which 
it  may  be  advisable  at  this  point  to 
explain.  The  two  principal  calculations 
to  be  made  involve  the  determination 
of  the  percentage  of  moisture  based  on 
the  weight  of  the  material  as  taken 
for  the  test  (that  is,  on  its  moist 
weight),  and  then  the  determination 
of  the  conditioned  weight  of  the  ma- 
terial based  on  a  definite  percentage  ^^ 
allowance  of  "  regain,"  this  percent- 
age being  calculated  on  the  dry  weight 


G.  408. — Freas  Conditioning  Oven 
with  Special  Thermostatic  Regula- 
tion of  Temperature. 


952 


TESTING  OF  TEXTILE  FABRICS 


of  the  material.     The  different  problems  in  conditioning  will  now  be 
considered.^ 

(1)  If  a  weight  (w)  of  material  after  drying  shows  a  weight  (o),  what  percentage  (x) 
of  moisture  does  it  contain? 

10— a  =  loss  in  weight  on  drying  =  moisture. 

w—a 


w 


■XlOO=a;,  percent  of  moisture. 


(2)  If  a  quantity  of  material  of  weight  (w)  contains  x  percent  of  moisture,  what 
is  its  dry  weight  (a)? 


/         X  \ 

a  =  w{  1 I, 

\       100/ 


(3)  If  from  a  weight  (W)  of  material  there  is  taken  a  sample  of  weight  (w)  and 
the  dried  weight  of  this  is  found  to  be  (a),  what  will  be  the  conditioned  weight  (C) 
of  the  material,  allowing  a  regain  of  (R)  per  cent? 

The  dry  weight  (A)  of  the  entire  material  will  be 


A^WX-, 

w 


and  the  conditioned  weight  will  be 

C  =  WX 


w\      100/ 


(4)  A  substance  is  conditioned  with  a  regain  of  (R)  percent,  what  percentage  of 
moisture  (x)  does  it  contain? 


We  have  the  proportion 


therefore 


100+R     100 

y 
X 


R 


x=- 


lOOR 


100+ R 

The  following  table  shows  the  percentage  of  moisture  in  any  material 
corresponding  to  a  definite  percentage  of  regain : 


Percent  Regain. 

Percent  of  Moisture. 

Percent  Regain. 

Percent  of  Moisture. 

5 

4.76 

12 

10.71 

6 

5.66 

12.5 

11.11 

7 

6.54 

13 

11.50 

7.5 

6.98 

14 

12.28 

8 

7.41 

15 

13.04 

8.5 

7.83 

16 

13.79 

9 

8.26 

17 

14.53 

10 

9.09 

18 

15.25 

11 

9.91 

19 

15.97 

20 

16.67 

See  Persoz,  Essai  des  Matibres  Textiles. 


CALCULATIONS  INVOLVED  IN  CONDITIONING 


953 


(5)  If  the  material  contains  (x)  percent  of  moisture,  what  will  be  the  corresponding 
percentage  of  regain  (i^)? 

This  is  the  reverse  of  the  previous  problem.     We  have 


R  = 


lOOx 
100 -x' 


The  following  table  shows  the   percentage   of  regain  of  any  material 
corresponding  to  a  definite  percentage  of  moisture : 


Percent  of  Moisture. 

Percent  Regain. 

Percent  of  Moisture. 

Percent  Regain. 

5 

5.26 

13 

14.94 

6 

6.38 

14 

16.28 

7 

7.53 

15 

17.65 

8 

8.70 

16 

19.05 

9 

9.89 

17 

20.48 

10 

11.11 

18 

21.95 

11 

12 ,  36 

19 

23.46 

12 

13.64 

20 

25.00 

Hartshorne  has  worked  out  some  mathematical  relations  concerning 
the  laws  of  regain  of  moisture  in  cotton  and  worsted.  His  general  con- 
clusions are  as  follows:  (1)  The  general  law  for  cotton  and  worsted  (and 
probably  for  any  other  textile  fiber)  may  be  expressed  by  the  formula, 

HKRT^=  7/(5771.44X108), 

in  which  H  represents  any  given  percent  of  relative  humidity,  R  the 
regain  at  any  absolute  temperature  T,  K  a  variable  coefficient  depending 
upon  both  H,  R,  and  T  in  such  a  way  that  for  H  =  l,  the  product  KRT-^ 
is  a  constant  quantity  represented  by  the  number  5771.44  XlO^.  This 
constant  number,  5771.44,  is  the  weight  in  grains  of  a  cubic  foot  of  water 
vapor  at  any  temperature  multiplied  by  the  corresponding  absolute 
temperature,  expressed  in  degrees  Fahrenheit,  divided  by  the  maximum 
elastic  force  of  water  vapor  at  that  temperature,  expressed  in  inches  of 
mercury.  (2)  For  any  given  temperature  the  relations  of  values  of  R 
to  the  variable  K,  for  both  worsted  and  cotton,  is  expressed  by  a  hyper- 
bolic equation  differing  for  each  substance.  (3)  For  any  other  tempera- 
ture the  law  for  worsted  is:  For  the  same  humidity  the  squares  for  the 
regains  at  different  temperatures  are  to  each  other  inversely  as  the  cubes 
of  the  corresponding  absolute  temperatures.  (4)  The  law  for  cotton  is: 
For  the  same  humidity  the  first  powers  of  the  regains  at  different  tem- 
peratures are  to  each  other  inversely  as  the  first  powers  of  the  corre- 
sponding absolute  temperatures. 

(6)  If  a  material  is  required  to  possess  a  definite  conditioned  weight  (C),  what 
percentage  of  regain  {R)  must  be  applied  to  the  dry  weight  (a)? 


a 

100 

C- 

-a 

'  R  ' 

R  = 

C- 
=  100  — 

-a 

954  TESTING   OF   TEXTILE   FABRICS 

We  have  the  proportion 

therefore 


(7)  If  the  dry  weight  (a)  of  any  material  is  given,  what  quantity  of  water  (q) 
would  it  have  to  absorb  in  order  to  contain  (j)  percent? 
We  have  the  proportion 

100-a-_a 

X  q 

therefore 

ax 
9  = 


100 -X 

The  weight  (IF)  of  the  material  after  absorbing  the  moisture  would  be 

a-\-q, 
or 

100a 


W  = 


100 -z 

(8)  If  the  dry  weight  (a)  of  a  material  is  given,  what  would  be  its  conditioned 
weight  (C),  allowing  (R)  percentage  of  regain? 

We  have  in  this  case 

C  =  a{  IH 

\       100 

(9)  If  the  conditioned  weight  (C)  of  a  material  is  given  with  a  percentage  of  regain 
{R),  what  is  its  dry  weight  (a)? 

From  the  previous  formula  we  have 

lOOC 
a  = 


100 +/2 


(10)  If  the  percentage  of  moisture  (x)  is  known  in  a  material,  what  will  be  t".  e 
conditioned  weight  (C),  allowing  a  regain  of  {R)  percent? 
The  dry  weight  (a)  will  be 


a[  1- 

100 

Therefore  the  conditioned  weight  with  {R)  percent  regain  will  be 

R 


C  =  a\  1 ■       1  + 

\       100/  \       100 

(11)  If  the  original  weight  {W)  of  a  material  is  known  and  also  its  conditioned 
weight  (C),  what  percentage  difference  in  weight  {D)  would  there  be  between  the 
original  weight  and  the  conditioned  weight? 
We  have  the  proportion 

W        100^ 
W-C~~D' 


CALCULATIONS  INVOLVED  IN  CONDITIONING  955 

therefore 

^_ioo(ir-c) 
w 

There  would  be  a  gain  or  loss  by  conditioning  according  to  whether  (W)  is  greater  or 
less  than  (C). 

(12)  If  the  conditioned  weight  (C)  of  a  material  is  given  and  also  its  percentage 
difference  (D)  on  conditioning,  find  the  original  weight  (W)  of  the  substance. 

From  the  previous  formula  we  have 

lOOC 

W  = . 

100 -D 

(13)  If  the  original  weight  (TF)  of  a  material  is  known  and  also  the  percentage 
difference  (D)  on  conditioning,  find  the  conditioned  weight  (C) . 

From  the  previous  formula  we  have 

TF(100-I>) 


C  = 


100 


(14)  If  a  material  contains  (x)  percent  of  moisture,  calculate  the  difference  (d) 
between  its  original  weight  (TF)  and  its  conditioned  weight  (C)  with  a  regain  of  (R) 
percent. 

This  difference  is 

d  =  W-C, 

and  from  the  formula  under  (10)  we  have 

''  =  "'-«'('-is)('+ifo 

hence 

W[{lOO+R)x-100R] 

~  io^oo 

If  (W)  in  this  formula  is  taken  as  equal  to  100,  the  expression  becomes  simplified  to 

d=D=ll-\ ~]x-R. 

\       100/ 

According  to  the  value  of  (x)  this  difference  will  be  positive  or  negative;   that  is  to 
say,  the  material  will  lose  or  gain  by  conditioning. 
If 

lOOR 
X  is  greater  than  ^^^ 

there  will  be  a  loss. 
If 

lOOR 

^~100+R 
the  fiber  will  be  in  its  conditioned  state. 
Finally,  if 

100/e 

X  is  less  than 


100+R 


the  material  will  gain  in  weight  by  conditioning. 

(15)  If  the  difference  (d)  between  the  original  weight  (TF)  of  a  material  and  its 
conditioned  weight  (C)  at  a  regain  of  (R)  percent  is  known,  find  the  percentage  of 
moisture  (x)  in  the  material. 


956  TESTING   OF   TEXTILE   FABRICS 

This  is  the  reverse  of  the  preceding  problem  and  may  be  solved  by  taking  the 
reciprocal  of  the  formula  for  (d),  as  follows: 

100(WR  +  I00d) 
W{100+R) 

If  we  take  the  original  weight  as  equal  to  100  and  call  (D)  the  corresponding  difference, 
the  expression  becomes 

_100iR+D) 
100+R 

It  is  necessary  to  remember  in  these  formulas  that  the  value  of  (d)  or  (D)  is  positive 
only  if  the  original  weight  is  greater  than  the  conditioned  weight;  if  the  contrary  is 
the  case,  the  difference  will  be  of  a  negative  value.  For  example,  a  sample  of  wool 
loses  2  percent  on  conditioning  at  15  percent  regain;    hence  it  contains 

100(15+2) 

=  14.7  percent  moisture, 

100  +  15 

whereas  if  it  gains  2  percent  in  weight  by  conditioning,  we  have 
100(15-2) 


100  +  15 


=  11.3  percent  moisture. 


(16)  A  sample  of  material  shows  a  difference  in  weight  of  (D)  percent  on  con- 
ditioning at  {R)  percent  regain,  what  difference  (D')  would  there  be  if  conditioned  at 
a  regain  of  (R')  percent? 

If  we  call  the  dry  weight  (a),  then 

D  =  100-o    l-\ 

'        100 

R^ 

100 

Hence,  by  eliminating  (a),  we  have 

{100+R')D-100(R'-R) 


7?' 
£>'  =  100-«(  IH 


D'  = 


100+R 


This  problem  will  often  arise  in  practice  where  two  different  sets  of  regains  are  to  be 
allowed.  For  example,  a  sample  of  wool  conditioned  at  a  regain  of  15  percent  loses 
0.4  percent  in  weight,  how  much  would  it  lose  if  the  regain  allowed  was  17  percent? 

^,     (117X0.4) -(100X2) 

D  = =  — 1.3  percent; 

115 

that  is  to  say,  the  fiber  would  gain  1.3  percent  in  weight. 

(17)  A  sample  of  material  on  conditioning  at  a  regain  of  (R)  percent  shows  a  loss 
of  (D)  percent,  what  regain  would  have  to  be  adopted  in  order  that  the  loss  may  be 
(D')  percent? 

From  the  previous  formula  we  have 

100(D+R)-D'{100+R) 
100- D 

(18)  If  the  conditioned  weight  (C)  at  a  regain  of  (R)  percent  is  known,  calculate 
the  conditioned  weight  (C)  at  a  regain  of  (R')  percent. 

From  the  formula  under  (8)  we  have 

C      100+R 
C'~  100+R'' 


CALCULATIONS  INVOLVED  IN  CONDITIONING  957 

hence 

100+R  ' 

(19)  In  a  textile  material  consisting  of  two  kinds  of  fibers,  if  the  percentage  con- 
ditioned amounts  of  the  two  fibers  are  known,  (C)  and  (C),  and  their  respective  regains 
are  (R)  and  {R'),  what  will  be  the  average  regain  (r)  and  the  average  amount  of 
moisture  (x)  in  the  mixture? 

If  (C)  and  (C)  are  the  conditioned  weights  of  the  two  fibers,  their  dry  weights  {A) 

and  {A')  would  be 

lOOC  ^  lOOC 

A= -,     and    A  = 


100+R'  lOO+i^'' 

the  average  moisture  would  be 

/  lOOC         lOOC  \ 

.T  =  100- 1 I; 

\100+/e     100+R'/' 

hence 


I       \100+i2     100+i?7  J 


The  average  regain  would  be 

lOOx 


100 -a: 
For  example,  suppose  we  have  conditioned  a  yarn  composed  of  65  percent  of  wool 
and  35  oercent  of  cotton,  with  respective  regains  of  15  and  7  percent.     Then 


=  100    l-l 


65       35_ 
115     107 


a:  =  9.6  percent  moisture, 
r  — 10.6  percent  average  regain. 
(20)  In  a  textile  of  mixed  fibers  if  the  proportion  (P)  and  (P')  of  the  two  fibers 
is  known  on  the  dry  weight  (A),  together  with  the  moisture  (x)  lost  on  drying,  what 
would  be  the  conditioned  weight  (C)  of  the  material,  allowing  (R)  and  (R')  respectively 
as  the  regains  for  the  two  fibers? 
We  have 

P 

— A  =  amount  of  first  fiber, 
100 


P' 

— -A  =  amount  of  second  fiber, 
100 


and 


/PA     _R^\      PA 

Vioo'^ioo/^ioo' 


=  conditioned  weight  of  first  fiber. 


P'A      R'  \     P'A 

X I  H =  conditioned  weight  of  second  fiber. 

100      100/      100 

Adding  these  two  terms  gives  us 

(PR  -\-P'R\ 
1+- I  =  conditioned  weight  of  entire  material. 
10,000   / 

For  example,  suppose  a  yarn  contains  60  percent  of  wool  and  40  percent  of  cotton 
on  a  dry  weight  of  85  lbs.,  allowing  respective  regains  of  15  and  7  percent,  what  would 
be  the  conditioned  weight  of  the  yarn? 

/       60X15+40X7\  ^  ^^^ 

\  10,000        / 


958 


TESTING  OF  TEXTILE  FABRICS 


TABLE  SHOWING  THE  CONDITIONED  WEIGHT  OF  100  POUNDS  OF  ANY 
MATERIAL  WITH  REGAINS  OF  7,  11  AND  15  PERCENT,  CONTAINING 
DIFFERENT  AMOUNTS  OF  MOISTURE 


Conditioned  Weight,  Regains. 

Percent, 

Conditioned  Weight,  Regains. 

Percent, 

Moisture. 

7 

11 

15 

Moisture. 

7 

11 

15 

Percent. 

Percent. 

Percent. 

Percent. 

Percent. 

Percent. 

5.0 

101.65 

105.45 

109.25 

9.0 

97.37 

101.01 

104.65 

.1 

101.54 

105.34 

109.14 

.1 

97.26 

100.90 

104.53 

.2 

101.44 

105.23 

109.02 

.2 

97.16 

100.79 

104.42 

.3 

101.33 

105.12 

108.91 

.3 

97.05 

100.68 

104.30 

.4 

101.22 

105.01 

108.79 

.4 

96.94 

100.57 

104.19 

.5 

101.12 

104.90 

108.68 

.5 

96.84 

100.46 

104.07 

.6 

101.01 

104.78 

108.56 

.6 

96.73 

100.34 

103.96 

.7 

100.90 

104.67 

108.45 

.7 

96.62 

100.23 

103.84 

.8 

100.80 

104.56 

108.33 

.8 

96.51 

100.12 

103.73 

.9 

100.69 

104.45 

108.22 

.9 

96.41 

100.01 

103.61 

6.0 

100.58 

104.34 

108.10 

10.0 

96.30 

99.90 

103.50 

.1 

100.48 

104.23 

107.99 

.1 

96.19 

99.79 

103.38 

.2 

100.37 

104.12 

107.87 

.2 

96.09 

99.68 

103.27 

.3 

100.26 

104.01 

107.76 

.3 

95.98 

99.57 

103.16 

.4 

100.15 

103.90 

107.64 

.4 

95.87 

99.46 

103.04 

.5 

100.05 

103.79 

107.53 

.5 

95.77 

99.34 

102.93 

.6 

99.94 

103.67 

107.41 

.6 

95.66 

99.23 

102.81 

.7 

99.83 

103.56 

107.30 

.7 

95.55 

99.12 

102.70 

.8 

99.72 

103.45 

107.18 

.8 

95.45 

99.01 

102.58 

.9 

99.62 

103.34 

107.07 

.9 

95.34 

98.90 

102.47 

7.0 

99.51 

103.23 

106.95 

11.0 

95.23 

98.79 

102.35 

.1 

99.40 

103.12 

106.84 

.1 

95.12 

98.68 

102.24 

.2 

99.30 

103.01 

106.72 

.2 

95.02 

98.57 

102.12 

.3 

99.19 

102.90 

106.61 

.3 

94.91 

98.46 

102.01 

.4 

99.08 

102.79 

106.49 

.4 

94.81 

98.35 

101.89 

.5 

98.98 

102.68 

106.38 

.5 

94.70 

98.23 

101.78 

.6 

98.87 

102.56 

106.26 

.6 

94.59 

98.12 

101.66 

.7 

98.76 

102.45 

106.15 

.7 

94.48 

98.01 

101.55 

.8 

98.66 

102 . 34 

106.03 

.8 

94.37 

97.90 

101.43 

.9 

98.55 

102.23 

105.92 

.9 

94.27 

97.79 

101.32 

8.0 

98.44 

102 . 12 

105.80 

12.0 

94.16 

97.68 

101.20 

.1 

98.34 

102.01 

105.69 

.1 

94.05 

97.57 

101.08 

.2 

98.23 

101.90 

105.57 

.2 

93.95 

97.46 

100.97 

.3 

98.12 

101.79 

105.46 

.3 

93.84 

97.35 

100.85 

.4 

98.01 

101.68 

105.34 

.4 

93.73 

97.24 

100.74 

.5 

97.90 

101.57 

105.23 

:5 

93.62 

97.12 

100.62 

.6 

97.80 

101.45 

105.11 

.6 

93.52 

97.01 

100.51 

.7 

97.69 

101.34 

105.00 

.7 

93.41 

96.90 

100.39 

.8 

97.58 

101.23 

104.88 

.8 

93 .  30 

96.79 

100.28 

.9 

97.48 

101.12 

104.77 

.9 

93.19 

96.68 

100.16 

CALCULATIONS  INVOLVED  IN  CONDITIONING  959 

TABLE  SHOWING  THE  CONDITIONED  \YEIGRT— Continued 


Conditioned  Weight, 

Regains. 

Percent, 

Conditioned  Weight,  Regains. 

Percent, 

Moisture. 

7 

11 

15 

Moisture. 

7 

11 

15 

Percent. 

Percent. 

Percent. 

Percent. 

Percent. 

Percent. 

13.0 

93.09 

96.57 

100.05 

17.0 

88.81 

92.13 

95.45 

.1 

92.98 

96.46 

99.94 

.1 

88.71 

92.02 

95.34 

.2 

92.88 

96.35 

99.82 

.2 

88.60 

91.91 

95.22 

.3 

92.77 

96.24 

99.71 

.3 

88.49 

91.80 

95.11 

.4 

92 .  66 

96.13 

99.59 

.4 

88.38 

91.69 

94.99 

.5 

92.55 

96.01 

99.48 

.5 

88.28 

91.57 

94.88 

.6 

92.45 

95.90 

99.36 

.6 

88.17 

91.46 

94.76 

.7 

92.34 

95.79 

99.25 

.7 

88.06 

91.35 

94.65 

.8 

92.23 

95.68 

99.13 

.8 

87.95 

91.24 

94.53 

.9 

92.12 

95.57 

99.02 

.9 

87.85 

91.13 

94.42 

14.0 

92.02 

95.46 

98.90 

18.0 

87.74 

91.02 

94.30 

.1 

91.91 

95.35 

98.78 

.1 

87.63 

90.91 

94.18 

.2 

91.81 

95.24 

98.67 

.2 

87.52 

90.80 

94.07 

.3 

91.70 

95.13 

98.56 

.3 

87.42 

90.69 

93.96 

.4 

91.59 

95.02 

98.44 

.4 

87.31 

90.58 

93.84 

.5 

91.49 

94.90 

98.33 

.5 

87.21 

90.46 

93.73 

.6 

91.38 

,  94.79 

98.21 

.6 

87.10 

90.35 

93.61 

.7 

91.27 

94.68 

98.10 

.7 

86.99 

90.24 

93.50 

.8 

91.16 

94.57 

97.98 

.8 

86.88 

90.13 

93.38 

.9 

91.05 

94.46 

97.87 

.9 

86.78 

90.02 

93.27 

15.0 

90.95 

94.35 

97.75 

19.0 

86.67 

89.91 

93.15 

.1 

90.84 

94.24 

97.64 

.1 

86.56 

89.80 

93.04 

.2 

90.74 

94.13 

97.52 

.2 

86.45 

86.69 

92.92 

.3 

90.63 

94.02 

97.41 

.3 

86.35 

89.58 

92.81 

.4 

90.52 

93.91 

97.29 

.4 

86.24 

89.47 

92.69 

.5 

90.42 

93.79 

97.18 

.5 

86.13 

89.36 

92.58 

.6 

90.31 

93.68 

97.06 

.6 

86.02 

89.24 

92.46 

.7 

90.20 

93.57 

96.95 

.7 

85.92 

89.13 

92.35 

.8 

90.09 

93.46 

96.83 

.8 

85.81 

89.02 

92.23 

.9 

89.98 

93.35 

96.72 

.9 

85.71 

88.91 

92.12 

16.0 

89.88 

93 .  24 

96.60 

20.0 

85.60 

88.80 

92.00 

.1 

89.77 

93.13 

96.48 

.1 

85.49 

88.69 

91,88 

.2 

89.67 

93.02 

96.37 

.2 

85.38 

88.58 

91.77 

.3 

89.56 

92.91 

96.26 

.3 

85.28 

88.47 

91.66 

.4 

89.45 

92.80 

96.14 

.4 

85.17 

88.36 

91.54 

.5 

89.34 

92.68 

96.03 

.5 

85.06 

88.25 

91.43 

.6 

89.24 

92.57 

95.91 

.6 

84.95 

88.13 

91.31 

.7 

89.13 

92.46 

95.80 

.7 

84.85 

88.02 

91.20 

.8 

89.02 

92.35 

95.68 

.8 

84.74' 

87.91 

91.08 

.9 

88.92 

92.24 

95.57 

.9 

84.63 

87.80 

90.97 

21.0 

84.53 

87.69 

90.85 

960  TESTING   OF   TEXTILE   FABRICS 

4.  Analysis  of  Weighting  in  Silk  Fabrics. — The  practice  of  adding  to 
the  weight  of  silk  in  the  dyeing  and  finishing  operations  has  become  so 
common  that  it  is  frequently  desirable  to  ascertain  in  a  sample  of  silk 
goods  the  amount  of  true  fiber  present  and  the  amount  and  character  of 
weighting.  Lewitzki  ^  calls  attention  to  the  fact  that  raw  silk  is  sometimes 
found  to  be  adulterated  with  weighting  materials.  These  consist  chiefly 
of  soap,  fat,  and  glycerol  and  some  silk  is  also  colored  with  Methyl  Orange. 
Such  silk  had  obviously  been  reeled  from  all  sorts  of  old  cocoons  and  then 
tinted  with  Methyl  Orange  to  give  it  the  appearance  of  a  uniform  product. 

Black-dyed  silk  is  especially  liable  to  contain  a  very  large  amount  of 
weighting  materials;  sometimes  the  degree  of  weighting  may  reach  as 
high  as  400  percent  or  even  more.  Colored  silks  are  usually  not  weighted 
to  such  a  great  extent,  but  they  will  frequently  be  found  also  to  contain 
considerable  adulteration.  Black-dyed  silks  are  mostly  loaded  with 
Prussian  blue  and  iron  tannate,  the  latter  being  obtained  by  immersing 
the  silk  in  a  solution  of  pyrolignite  or  nitrate  of  iron,  and  subsequently 
in  a  solution  of  cutch  or  other  tannin.  Colored  silks  are  principally 
weighted  with  tin  phosphate  obtained  by  treating  the  material  with 
solutions  of  tin  perchloride  and  sodium  phosphate.  Sometimes  light- 
colored  silks  are  also  weighted  with  sugar,  magnesium  chloride,  etc.  Such 
materials  are  soluble  in  warm  water,  and  hence  their  use  is  easily  detected. 

A  convenient  test  which  is  frequently  apphcable  to  detect  weighting  is 
to  ignite  the  silk  fiber;  if  it  is  heavily  weighted  it  will  not  inflame,  but 
gradually  smolder  away  and  leave  a  coherent  ash  retaining  the  original 
form  of  the  fiber. 

In  general  the  substances  which  may  be  present  as  weighting  materials 
are  iron,  as  ferrocyanide  or  tannate;  tin,  as  tannate,  tungstate,  phosphate, 
silicate,  or  hydroxide;  chromium  compounds;  the  sulfates  or  chlorides 
of  sodium,  magnesium,  and  barium;  organic  matters,  such  as  sugar,  glu- 
cose, gelatine,  tannins,  etc. 

The  following  method  is  one  which  has  been  recommended  for  the 
qualitative  analysis  of  weighting  materials  on  silk:-  Substances  that  are 
easily  soluble,  such  as  sugar,  glucose,  glycerol,  magnesium  salts,  etc.,  are 
estimated  directly  by  boiling  the  silk  with  water  and  testing  the  extract 
with  Fehling's  solution,  etc.^     From  2  to  3  grams  of  the  silk  are  ignited 

^Fdrber.-Zeit.,  1911,  p.  42. 

2  Silbermann,  Chern.  Zeil.,  vol  18,  p.  744. 

'  Fehling's  reagent  is  an  alkaline  solution  of  copper  sulfate  containing  potassium 
tartrate.  It  is  prepared  in  the  following  manner:  34.639  grams  of  pure  crystallised 
copper  sulfate  are  dissolved  in  about  250  cc.  of  water;  173  grams  of  Rochelle  salt 
(sodium  potassium  tartrate)  are  dissolved  in  the  same  quantity  of  water;  60  grams 
of  caustic  soda  are  similarly  dissolved.  The  three  solutions  are  then  mixed,  and  the 
mixture  diluted  to  1000  cc.  with  water.  The  reagent  is  employed  as  follows:  10  cc, 
of  the  solution  are  diluted  with  40  cc.  of  water  and  brought  to  a  boil;    there  is  the-i 


ANALYSIS  OF   WEIGHTING   IN  SILK  FABRICS  961 

and  the  ash  is  tested  for  tin  (which  may  be  present  in  the  fiber  as  basic 
chloride  and  stannic  acid),  chromium,  iron,  etc. 

These  metals  may  be  tested  for  in  the  ash  in  the  following  manner: 
Moisten  with  a  few  drops  of  nitric  acid  and  re-ignite  in  order  to  be  certain 
that  all  carbon  is  removed.  Treat  the  residue  with  eight  to  ten  drops  of 
strong  sulfuric  acid;  and  gently  heat  until  fumes  are  evolved;  allow  to 
cool  and  boil  with  water,  dilute  to  about  100  cc.  with  water,  and  then  pass 
hydrogen  sulfide  gas  through  the  liquid;  filter,  and  examine  the  solution 
and  precipitate  as  follows :  The  aqueous  solution  may  contain  zinc  or  iron ; 
add  a  few  drops  of  bromine  water  to  remove  excess  of  hydrogen  sulfide  and 
to  oxidise  any  iron  present  to  the  ferric  condition;  boil,  then  add  ammonia 
in  slight  excess;  boil  again,  and  filter;  if  there  is  a  precipitate,  it  may 
contain  iron;  if  so,  it  should  be  brown  in  color;  dissolve  in  a  little  hydro- 
chloric acid  and  add  a  few  drops  of  a  solution  of  potassium  f errocyanide ; 
a  blue  color  will  confirm  the  presence  of  iron.  The  filtrate,  which  may 
contain  zinc,  should  be  heated  to  the  boil,  and  a  few  drops  of  potassium 
ferrocyanide  solution  added;  a  white  precipitate  will  indicate  zinc.  The 
original  precipitate  produced  by  the  treatment  with  hydrogen  sulfide  is 
next  examined.  This  may  contain  lead,  tin,  or  copper;  it  is  fused  for 
ten  minutes  in  a  porcelain  crucible  with  2  grams  of  a  mixture  of  potash 
and  soda  ash  together  with  1  gram  of  sulfur.  On  cooling,  the  mass  is 
boiled  with  water  and  filtered.  The  residue  may  contain  lead  and  copper; 
it  is  boiled  with  strong  hydrochloric  acid  and  a  few  drops  of  bromine 
water  are  added  for  the  purpose  of  completely  oxidising  any  copper  sulfide 
present;  filter  if  necessary,  and  add  to  the  filtrate  an  excess  of  ammonia, 
when  a  blue  color  will  indicate  presence  of  copper.  Acidulate  the  liquid 
with  acetic  acid  and  divide  into  two  portions:  to  the  first  add  a  few  drops 
of  a  solution  of  potassium  bichromate;  a  yellow  precipitate  will  confirm  the 
presence  of  lead;  to  the  other  add  a  few  drops  of  a  solution  of  potassium 
ferrocyanide,  when  a  brown  precipitate  or  coloration  will  indicate  presence 
of  copper.  The  filtrate  from  the  residue  after  the  above  fusion  is  acidulated 
with  acetic  acid,  when  a  yellow  precipitate  of  stannic  sulfide  will  indicate 
the  presence  of  tin.  The  latter  test  may  be  confirmed  by  dissolving  the 
precipitate  of  stannic  sulfide  in  hydrochloric  acid  and  bromine  water.  The 
filtered  solution  is  then  boiled  with  small  pieces  of  metallic  iron  to  reduce  the 

added  a  portion  of  the  solution  to  be  tested  for  sugar  (or  glucose)  which  has  previously 
been  boiled  with  a  small  quantity  of  dilute  hydrochloric  acid.  If  sugar  is  present,  the 
Fehling's  solution  will  be  decolorised  and  a  bright  red  precipitate  of  cuprous  oxide  will 
be  thrown  down.  This  test  may  be  made  quantitative  by  using  a  known  quantity 
of  sugar  solution,  filtering  off  the  cuprous  o.xide,  igniting,  and  finally  weighing  as 
copper  oxide  (CuO).  In  order  to  determine  the  amount  of  sugar  (or  glucose)  corre- 
sponding to  this  latter,  reference  should  be  made  to  tables  constructed  by  Allihn 
showing  the  proper  equivalents  of  sugar  and  glucose  for  the  amounts  of  copper  oxide 
determined. 


962  TESTING  OF  TEXTILE   FABRICS 

tin;  the  liquid  is  diluted  and  filtered  and  a  drop  of  mercuric  chloride  solution 
is  added,  when  a  white  or  gray  turbidity  will  be  produced  if  tin  is  present. 
Fatty  matters,  wax,  and  parafiine  are  detected  by  extraction  with  ether 
or  benzene. 

Japan  tram  silk  is  sometimes  weighted  with  fatty  substances.  The 
normal  amount  of  fat  in  raw  silk  never  exceeds  0.06  percent.  A  direct 
determination  of  the  fatty  matters  may  be  made  by  treating  5  grams  of 
the  silk  sample  in  a  stoppered  flask  with  pure  benzene  three  or  four  times 
successively,  using  about  60  cc.  of  the  solvent  each  time  and  allowing  it  to 
act  from  two  to  four  hours  with  frequent  shaking.  The  several  portions  of 
benzene  are  brought  together  and  evaporated  to  dryness  in  a  tared  dish 
and  the  fatty  residue  is  weighed.  Another  method  is  to  extract  with 
ether  in  a  Soxhlet  apparatus. 

To  detect  mineral  weighting  the  silk  is  soaked  in  warm  dilute  hydro- 
chloric acid  (1:2)  after  complete  removal  of  fatty  matters;  if  the  fiber  is 
almost  decolorised  by  this  treatment,  only  a  slight  yellow  tint  remaining, 
while  the  solution  assumes  a  deep  brownish  color  not  changed  to  violet  by 
addition  of  lime-water,  it  is  safe  to  conclude  that  the  silk  has  been  weighted 
by  alternate  passages  through  baths  of  iron  salts  and  tannin.  The  yellow 
color  of  the  fiber  is  due  to  a  residuum  of  tannin,  and  the  precise  shade 
(from  greenish  to  brownish  yellow)  enables  some  idea  to  be  formed  as  to 
the  nature  of  the  tanning  material  used  (sumac,  divi-divi,  cutch,  etc.). 
Decolorisation  of  the  fiber,  the  acid  extract  being  pink,  and  changing  to 
violet  by  lime-water,  indicates  a  logwood  black.  If  the  fiber  retain  a 
deep  greenish  tint  and  the  solution  be  yellow  and  unaffected  by  lime- 
water,  the  black  is  dyed  on  a  bottom  of  Prussian  blue.  If  the  latter  has 
been  produced  during  the  final  stage  of  dyeing,  this  will  be  shown  by  its 
solubility  in  the  acid.  A  green  fiber  and  pink  solution,  changing  to 
violet  on  addition  of  lime-water,  indicate  a  logwood  black  dyed  on  a 
bottom  of  Berlin  blue.  In  the  hydrochloric  acid  solution,  such  metals  as 
lead,  tin,  iron,  chromium,  and  aluminium  may  be  determined.  Blacks 
produced  by  artificial  dyes  on  a  bottom  of  iron-tannin  or  iron-blue-tannin 
may  be  recognised  by  the  coloration  imparted  to  acid  and  caustic  soda 
solutions.  With  blacks  produced  solely  with  coal-tar  dyes,  treatment  with 
a  hydrochloric  acid  solution  of  stannous  chloride  does  not  affect  aniline 
and  alizarine  blacks;  naphthol  black  is  changed  to  reddish  brown,  and 
wool  black  becomes  yellowish  brown.  Tannin  materials  in  general  may 
be  extracted  by  alkalies,  and  subsequently  precipitated  and  distinguished 
by  ferric  acetate.  To  remove  the  whole  of  the  weighting  material  and  the 
dye,  the  silk  should  be  boiled  with  acid  potassium  oxalate,  washed  with 
dilute  hydi'ochloric  acid,  and  finally  treated  with  soda  solution.  When 
iron  and  tin  are  both  present  in  the  fiber,  it  is  best  to  first  extract  the  tin 
by  treatment  with  a  solution  of  sodium  sulfide. 


ANALYSIS  OF   WEIGHTING   IN   SILK   FABRICS  963 

Persoz  recommends  in  testing  for  tin  weighting  on  dark-colored  and 
black  silks  to  boil  the  sample  for  a  few  minutes  in  concentrated  hydrochloric 
acid.  Then  dilute  and  filter  the  acid,  and  pass  hydrogen  sulfide  into  it, 
when  a  yellow  precipitate  (SnS)  would  indicate  the  presence  of  tin. 

Vignon  has  proposed  using  the  specific  gravity  of  the  silk  sample  as  a 
means  of  determining  the  proportion  of  weighting  materials  present; 
but  this  method  cannot  be  recommended  as  being  at  all  practical,  as  the 
specific  gravity  of  the  weighting  materials  themselves  would  have  to  be 
known.  The  specific  gravity  of  the  silk  may  readily  be  determined  as 
follows:  A  small  sample  is  weighed  as  usual  in  the  air;  it  is  then  suspended 
in  benzene  and  the  weight  again  taken.  The  difference  between  the  two 
weighings  will  give  the  loss  of  weight  in  benzene ;  this  loss  divided  into  the 
original  weight  in  air  and  multiplied  by  the  density  of  the  benzene  will  give 
the  specific  gravity  of  the  silk.  The  specific  gravity  of  silk  and  of  other 
fibers  determined  in  this  way  is  as  follows: 

Silk,  raw 1.30  to  1.37 

Silk,  boiled-off 1 .25 

Wool 1.28  to  1.33 

Cotton 1.50  to  1.55 

Mohair 1.30 

Hemp 1 .48 

Ramie 1.51  to  1.52 

Linen 1 .  50 

Jute 1.48 

For  the  examination  of  white  silk  Allen  recommends  the  following  :i 
(1)  The  total  soluble  weighting  materials  are  determined  by  treating  a 
known  weight  of  the  sample  four  to  five  times  with  hot  water,  redrying,  and 
weighing.  The  Milan  Commission  fixed  a  limit  of  1.5  percent  for  the 
proportion  of  soluble  materials,  and  gave  the  method  for  their  determina- 
tion as  follows:  The  dried  silk  is  heated  for  thirty  minutes  with  ten  times 
its  weight  of  distilled  water  at  50°  to  55°  C.  in  a  closed  metal  tube;  the 
water  being  then  changed  and  the  heating  continued  for  another  thirty 
minutes,  at  the  same  temperature.  As  the  hygroscopic  character  of  silk 
is  very  variable,  it  is  best  to  employ  a  blank  sample  of  a  standard  silk, 
and  after  redrying  until  the  blank  sample  has  regained  its  normal  weight 
the  test  sample  is  weighed,  the  loss  representing  the  matters  soluble  in 
water.  In  the  solution,  after  suitable  evaporation,  glucose  may  be  deter- 
mined directly  by  means  of  Fehling's  solution,  and  cane-su^ar  after  inver- 
sion by  boiling  with  dilute  hydrochloric  acid.  Sulfates  and  chlorides 
and  magnesium  may  be  detected  and  determined  as  usual.  Sulfates  are 
detected  by  a  small  portion  of  the  solution  in  a  test-tube,  adding  a  few 
drops  of  dilute  hydrochloric  acid  and  then  a  few  drops  of  a  solution  of 
'  Commer.  Org.  Anal.,  vol.  4,  p.  527. 


962  TESTING  OF  TEXTILE   FABRICS 

tin;  the  liquid  is  diluted  and  filtered  and  a  drop  of  mercuric  chloride  solution 
is  added,  when  a  white  or  gray  turbidity  will  be  produced  if  tin  is  present. 
Fatty  matters,  wax,  and  paraffine  are  detected  by  extraction  with  ether 
or  benzene. 

Japan  tram  silk  is  sometimes  weighted  with  fatty  substances.  The 
normal  amount  of  fat  in  raw  silk  never  exceeds  0.06  percent.  A  direct 
determination  of  the  fatty  matters  may  be  made  by  treating  5  grams  of 
the  silk  sample  in  a  stoppered  flask  with  pure  benzene  three  or  four  times 
successively,  using  about  60  cc.  of  the  solvent  each  time  and  allowing  it  to 
act  from  two  to  four  hours  with  frequent  shaking.  The  several  portions  of 
benzene  are  brought  together  and  evaporated  to  dryness  in  a  tared  dish 
and  the  fatty  residue  is  weighed.  Another  method  is  to  extract  with 
ether  in  a  Soxhlet  apparatus. 

To  detect  mineral  weighting  the  silk  is  soaked  in  warm  dilute  hydro- 
chloric acid  (1:2)  after  complete  removal  of  fatty  matters;  if  the  fiber  is 
almost  decolorised  by  this  treatment,  only  a  slight  yellow  tint  remaining, 
while  the  solution  assumes  a  deep  brownish  color  not  changed  to  violet  by 
addition  of  lime-water,  it  is  safe  to  conclude  that  the  silk  has  been  weighted 
by  alternate  passages  through  baths  of  iron  salts  and  tannin.  The  yellow 
color  of  the  fiber  is  due  to  a  residuum  of  tannin,  and  the  precise  shade 
(from  greenish  to  brownish  yellow)  enables  some  idea  to  be  formed  as  to 
the  nature  of  the  tanning  material  used  (sumac,  divi-divi,  cutch,  etc.). 
Decolorisation  of  the  fiber,  the  acid  extract  being  pink,  and  changing  to 
violet  by  lime-water,  indicates  a  logwood  black.  If  the  fiber  retain  a 
deep  greenish  tint  and  the  solution  be  yellow  and  unaffected  by  lime- 
water,  the  black  is  dyed  on  a  bottom  of  Prussian  blue.  If  the  latter  has 
been  produced  during  the  final  stage  of  dyeing,  this  will  be  shown  by  its 
solubility  in  the  acid.  A  green  fiber  and  pink  solution,  changing  to 
violet  on  addition  of  lime-water,  indicate  a  logwood  black  dyed  on  a 
bottom  of  Berlin  blue.  In  the  hydrochloric  acid  solution,  such  metals  as 
lead,  tin,  iron,  chromium,  and  aluminium  may  be  determined.  Blacks 
produced  by  artificial  dyes  on  a  bottom  of  iron-tannin  or  iron-blue-tannin 
may  be  recognised  by  the  coloration  imparted  to  acid  and  caustic  soda 
solutions.  With  blacks  produced  solely  with  coal-tar  dyes,  treatment  with 
a  hydrochloric  acid  solution  of  stannous  chloride  does  not  affect  aniline 
and  alizarine  blacks;  naphthol  black  is  changed  to  reddish  brown,  and 
wool  black  becomes  yellowish  brown.  Tannin  materials  in  general  may 
be  extracted  by  alkalies,  and  subsequently  precipitated  and  distinguished 
by  ferric  acetate.  To  remove  the  whole  of  the  weighting  material  and  the 
dye,  the  silk  should  be  boiled  with  acid  potassium  oxalate,  washed  with 
dilute  hydrochloric  acid,  and  finally  treated  with  soda  solution.  When 
iron  and  tin  are  both  present  in  the  fiber,  it  is  best  to  first  extract  the  tin 
by  treatment  with  a  solution  of  sodium  sulfide. 


ANALYSIS   OF   WEIGHTING   IN   SILK   FABRICS  963 

Persoz  recommends  in  testing  for  tin  weighting  on  dark-colored  and 
black  silks  to  boil  the  sample  for  a  few  minutes  in  concentrated  hydrochloric 
acid.  Then  dilute  and  filter  the  acid,  and  pass  hydrogen  sulfide  into  it, 
when  a  yellow  precipitate  (SnS)  would  indicate  the  presence  of  tin. 

Vignon  has  proposed  using  the  specific  gravity  of  the  silk  sample  as  a 
means  of  determining  the  proportion  of  weighting  materials  present; 
but  this  method  cannot  be  recommended  as  being  at  all  practical,  as  the 
specific  gravity  of  the  weighting  materials  themselves  would  have  to  be 
known.  The  specific  gravity  of  the  silk  may  readily  be  determined  as 
follows:  A  small  sample  is  weighed  as  usual  in  the  air;  it  is  then  suspended 
in  benzene  and  the  weight  again  taken.  The  difference  between  the  two 
weighings  will  give  the  loss  of  weight  in  benzene ;  this  loss  divided  into  the 
original  weight  in  air  and  multiplied  by  the  density  of  the  benzene  will  give 
the  specific  gravity  of  the  silk.  The  specific  gravity  of  silk  and  of  other 
fibers  determined  in  this  way  is  as  follows: 

Silk,  raw 1.30  to  1.37 

Silk,  boiled-off 1 .25 

Wool 1 .  28  to  1 .  33 

Cotton 1 .  50  to  1 .  55 

Mohair 1.30 

Hemp 1 .  48 

Ramie 1.51  to  1.52 

Linen 1 .  50 

Jute 1.48 

For  the  examination  of  white  silk  Allen  recommends  the  following:^ 
(1)  The  total  soluble  weighting  materials  are  determined  by  treating  a 
known  weight  of  the  sample  four  to  five  times  with  hot  water,  redrying,  and 
weighing.  The  Milan  Commission  fixed  a  limit  of  1.5  percent  for  the 
proportion  of  soluble  materials,  and  gave  the  method  for  their  determina- 
tion as  follows:  The  dried  silk  is  heated  for  thirty  minutes  with  ten  times 
its  weight  of  distilled  water  at  50°  to  55°  C.  in  a  closed  metal  tube;  the 
water  being  then  changed  and  the  heating  continued  for  another  thirty 
minutes,  at  the  same  temperature.  As  the  hygroscopic  character  of  silk 
is  very  variable,  it  is  best  to  employ  a  blank  sample  of  a  standard  silk, 
and  after  redrying  until  the  blank  sample  has  regained  its  normal  weight 
the  test  sample  is  weighed,  the  loss  representing  the  matters  soluble  in 
water.  In  the  solution,  after  suitable  evaporation,  glucose  may  be  deter- 
mined directly  by  means  of  Fehling's  solution,  and  cane-sugar  after  inver- 
sion by  boiling  with  dilute  hydrochloric  acid.  Sulfates  and  chlorides 
and  magnesium  may  be  detected  and  determined  as  usual.  Sulfates  are 
detected  by  a  small  portion  of  the  solution  in  a  test-tube,  adding  a  few 
drops  of  dilute  hydrochloric  acid  and  then  a  few  drops  of  a  solution  of 
*  Commer.  Org.  Anal.,  vol.  4,  p.  527. 


966  TESTING  OF   TEXTILE   FABRICS 

between  each  bath.  The  silk  must  be  carefully  handled,  as  it  becomes 
quite  brittle;  after  drying  at  110°  C.  it  is  weighed;  the  loss  in  weight 
represents  the  total  weighting  materials.  As  a  certain  loss  of  silk  occurs 
in  this  treatment,  the  amount  of  weighting  material  found  is  generally 
somewhat  in  excess  of  the  truth.  The  chief  source  of  error,  however,  is 
in  the  uncertainty  of  the  allowance  to  be  made  for  loss  in  the  weight  of 
the  silk  by  boiling  off.  For  boiled-off  silk  this  figure  (d)  is  taken  at  25 
percent ;  for  souple  silk  at  8  percent ;  for  ecru  at  0  percent ;  and  for  fancy 
silks  at  10  percent.  Calling  p  the  original  weight  of  the  sample,  and  D 
the  weight  after  treatment,  the  percentage  of  weighting,  W,  may  be 
calculated  from  the  following  formula: 

^^,    (m-d)x{p-D) 

W= D • 

In  cases  where  the  treated  silk  leaves  a  sensible  amount  (A)  of  ash  on 
ignition,  the  following  formula  must  be  used: 

{p-D-\-1.25A)X{l00-d) 
^~  D-1.25A 

as  the  weight  of  the  ash,  if  multiplied  by  the  factor  1.25,  will  give  approx- 
imately the  amount  of  metallic  hydroxides  retained  by  the  treated  silk. 

The  foregoing  method  of  Silbermann,  however,  is  not  sufficiently 
accurate  for  such  a  long  and  tedious  process. 

According  to  Ristenpart  ^  the  weighting  on  silk  may  be  determined 
by  extracting  1-3  grams  of  the  sample  with  25  cc.  of  a  4  percent  solution 
of  caustic  soda.  He  considers  this  more  expeditious  than  the  nitrogen 
method,  while  it  is  sufficiently  accurate  for  all  practical  purposes.  It 
will  not  answer,  however,  for  iron  mordanted  silk,  in  which  case,  it  is 
recommended  to  extract  the  organic  matter,  and  subsequently  estimate 
the  ash. 

The  method  of  analysing  weighted  silk,  recommended  by  Konigs 
of  the  silk-conditioning  establishment  at  Crefeld,  is  as  follows:  (1)  Deter- 
mine moisture  by  drying  at  110°  C;  (2)  Fatty  matters  by  extraction  with 
ether;  (3)  Boil  out  the  silk-glue  with  water;  (4)  Dissolve  out  Prussian 
blue  with  dilute  caustic  soda;  re  precipitate  by  acidifying  and  adding 
ferric  chloride,  ignite  precipitate  with  nitric  acid,  and  weigh  as  ferric 
•oxide;  1  part  of  Fe203  =  1.5  parts  of  Prussian  blue;  (5)  Estimate  stannic 
oxide  in  ash  of  silk  and  calculate  as  catechu  tannate  of  tin;  1  part  of 
Sn02  =  3.33  parts  of  catechu  tannate;  (6)  Estimate  total  ferric  oxide  in 
ash,  subtract  that  existing  as  Prussian  blue,  and  the  amount  naturally 
present  in  dyed  silk  (0.4  to  0.7  percent),  and  calculate  the  remainder  to 
tannate  of  iron;  1  part  of  Fe203  =  7.2  parts  of  ferric  tannate.^ 

^Fdrb.Zeit.,  1909,  p.  126. 

2  Persoz  states  that  in  many  silk  works  in  Lyons  it  is  the  custom  to  resort  to  the 


ANALYSIS  OF  WEIGHTING  IN  SILK  FABRICS  967 

For  the  extraction  of  weighting  materials  from  black-dyed  silk 
Heermann  ^  recommends  the  use  of  a  mixture  of  equal  parts  of  glycerol 
and  normal  potassium  hydroxide  solution.  The  sample  of  silk  is  heated 
with  this  reagent  to  about  80°  C.  on  the  water-bath  for  ten  minutes. 
Black  dyes  and  Prussian  blue  are  rapidly  extracted  by  this  reagent  with- 
out injury  to  the  silk  fiber.  In  case  the  weighting  materials  contain  tin 
compounds  in  addition  to  Prussian  blue,  successive  extractions  should  be 
given  with  the  glycerol-alkali  solution,  with  cold  20  percent  hydrochloric 
acid,  and  again  with  glycerol-alkali. 

Perhaps  the  most  accurate  method  of  analysing  silk  for  total  amount 
of  weighting  is  to  determine  the  amount  of  nitrogen  present  as  silk  by 
Kjeldahl's  process.^  To  do  this  it  is  first  necessary  to  remove  all  gelatine, 
Prussian  blue,  or  other  nitrogenous  matters.^  This  is  effected  by  boiling 
a  weighed  quantity  of  the  silk  (about  2  grams)  with  a  2  percent  solution 
of  sodium  carbonate  for  thirty  minutes.  The  silk  is  then  washed,  and 
heated  to  60°  C.  for  thirty  minutes  in  water  containing  1  percent  of 
hydrochloric  acid,  and  afterward  well  washed  in  hot  water.  This  treat- 
ment with  alkali  and  acid  should  be  repeated  until  the  sample  no  longer 
has  a  blue  color.  With  souple  or  ecru  silks,  ammonia  or  ammonium  car- 
bonate should  be  used  instead  of  sodium  carbonate,  and  the  silk  should  be 
finally  boiled  for  an  hour  and  a  half  in  a  solution  containing  25  grams  of 
soap  per  liter.  After  this  preparation  the  nitrogen  determination  is 
conducted  as  follows:  The  sample  is  placed  in  a  round-bottomed  flask 
of  hard  glass,  and  treated  with  about  20  cc.  of  strong  sulfuric  acid,  with 
the  addition  of  a  single  drop  of  mercury.  The  flask  is  then  heated, 
gently  at  first,  and  then  to  a  vigorous  boil;  then  10  grams  of  potassium 
sulfate  are  added  and  the  boiling  continued  until  the  contents  of  the 
flask  are  clear  and  colorless.  The  contents  are  then  washed  into  a  distilling- 
flask  and  connected  with  a  suitable  condenser.  By  means  of  a  tap- 
funnel,  an  excess  of  caustic  soda  solution  is  gradually  added,  together 
with  a  httle  sodium  sulfide  to  decompose  any  nitrogen  compounds  of 

following  method  of  calculation,  which,  however,  he  considers  as  too  empirical:  The 
proportion  of  ash  of  the  silk  sample  having  been  obtained,  the  weight  is  (1)  multipUed 
by  1.27  and  (2)  the  product  is  subtracted  from  100,  and  (3)  the  difference  is  mul- 
tiplied by  4/3,  and  (4)  the  number  so  obtained  is  divided  into  1000,  and  (5)  from  the 
quotient  100  is  subtracted.  The  figure  that  is  finally  obtained  represents  the  amount 
of  weighting.  This  method,  however,  does  not  seem  to  work  out  sensibly  from  the 
percentage  of  ash,  and  Persoz  must  have  incorrectly  reported  the  mathematical  opera- 
tions involved. 

^  Fdrber.  Zeit.,  1909,  p.  75 

^Gnehm  and  Blenner,  Rev.  Gen.  Mat.  Col,  April,  1898. 

3  According  to  Sisley  (Mev.  Gen.  Mat  Col ,  1907)  the  amount  of  nitrogen  in  dry 
fibroine,  obtained  as  a  mean  of  a  number  of  analyses  of  various  authorities,  is  18.4 
percent.  This  figured  to  air-dried  silk  with  11  percent  of  moisture  would  be  17.4 
percent.     The  proper  factor  would  then  be  5.62  instead  of  5.68. 


968  TESTING  OF  TEXTILE  FABRICS 

mercury  that  may  have  been  formed.  Some  granulated  zinc  is  placed 
in  the  flask  to  prevent  bumping,  and  the  distillate  is  collected  in  a 
measured  quantity  of  standard  acid,  which  takes  up  the  ammonia  that 
distils  over.  Excess  of  acid  is  determined  by  titration  with  standard 
alkali,  using  Methyl  Orange  as  an  indicator  of  neutrality.  The  above 
method  is  based  on  the  fact  that  when  silk  (in  common  with  the  great 
majority  of  other  nitrogenous  organic  substances)  is  heated  with  concen- 
trated sulfuric  acid,  the  whole  of  the  nitrogen  present  is  eventually  con- 
verted into  ammonia.  Air-dried  silk  with  11  percent  of  hygroscopic 
moisture  contains  17.6  percent  of  nitrogen,  consequently  the  amount 
of  true  silk  in  a  sample  may  be  obtained  by  multipljnng  the  percentage 
of  nitrogen  found  by  the  factor  5.68.  This  method  yields  very  accurate 
results  if  the  determination  of  the  nitrogen  is  carefulh'  conducted. 

Sisley  recommends  that  the  Kjeldahl  method  be  carried  out  as  follows: 
About  2  grams  of  the  silk  are  boiled  for  ten  minutes  with  a  25  percent 
acetic  acid  solution,  then  rinsed  in  water,  immersed  for  ten  minutes  in  a 
3  percent  solution  of  trisodium  phosphate  at  50°  C,  rinsed  again,  and  then 
boiled  twice  for  twenty  minutes  in  a  solution  containing  3  percent  of 
soap  and  0.2  percent  of  sodium  carbonate.  The  silk  thus  purified  is 
wrapped  in  a  piece  of  cotton  cloth  and  gently  heated  with  20  cc.  of  strong 
sulfuric  acid,  10  grams  of  potassium  sulfate,  and  0.5  gram  of  copper 
sulfate  until  effervescence  ceases,  after  which  the  liquid  is  boiled  until 
colorless,  and  the  ammonia  distilled  in  the  usual  manner. 

Persoz  ^  recommends  the  following  method  for  the  examination  of 
black  silks:  A  sample  is  taken  weighing  from  4  to  5  grams,  being  allowed 
to  first  acquire  its  normal  amount  of  moisture  before  weighing,  as  dr3ang 
at  high  temperatures  may  remove  moisture  which  should  be  regarded 
as  weighting.  The  sample  is  then  treated  to  the  alternate  action  of  cold 
acid  and  alkaline  solutions,  flasks  of  about  250  cc.  capacity  being  particu- 
larly useful  for  this  purpose  as  with  them  quite  a  number  of  samples 
may  be  treated  simultaneously.  The  acid  solution  is  prepared  with 
3  volumes  of  water  and  1  volume  of  commercial  hj'drochloric  acid, 
while  the  alkaline  solution  consists  of  caustic  soda  lye  of  6°  Tw.  These 
reagents  when  employed  in  the  cold  do  not  attack  the  fibroine  as  would 
be  the  case  if  heat  were  employed.  After  the  first  acid  bath  the  liquor 
becomes  charged  with  logwood  and  iron  salts  and  acquires  a  reddish 
appearance.  At  the  end  of  about  thirty  minutes  the  sample  is  removed, 
rinsed,  pressed  and  then  placed  in  the  alkaline  liquor.  In  this  bath 
the  logwood,  fustic,  cutch  and  other  astringents  pass  into  solution;  also 
Prussian  l)lue  which  is  largely  employed  as  a  base  for  logwood  black, 
is  destroyed  by  the  caustic  soda,  leaving  on  the  fiber  oxide  of  iron,  which 
is  removed  by  the  subsequent  treatment  with  acid.  Some  advantage 
1  Rev.  Gen.  Mat.  Col.,  1906,  p.  322. 


ANALYSIS  OF  WEIGHTING  IN  SILK  FABRICS  969 

is  gained  by  adding  to  the  alkaline  liquor  a  small  quantity  of  sodium 
sulfide,  as  the  sulfides  formed  on  the  fiber  are  more  readily  dissolved  in  the 
succeeding  acid  bath.  After  thirty  minutes'  treatment  in  the  alkaline 
bath  the  sample  is  removed,  washed,  and  submitted  to  the  action  of  a 
fresh  portion  of  the  acid  solution.  This  treatment  is  repeated  alternately 
until  the  silk  has  lost  the  greater  amount  of  its  coloring  matter.  When 
the  reagents  are  seen  to  remove  no  further  matter  from  the  silk  the  sample 
is  then  boiled  for  thirty  minutes  in  a  2  percent  soap  bath,  followed  by  a 
thorough  rinsing  with  hot  distilled  water.  The  silk  will  now  show  the 
appearance  of  a  light  brown  or  maroon  color,  indicating  that  the  fiber 
still  retains  a  considerable  part  of  the  astringent  matters.  The  sample 
is  then  steeped  in  a  bath  containing  1  volume  of  hj^drogen  peroxide  and 
3  volumes  of  water  at  60°  C.  and  a  small  quantity  of  magnesium 
hydrate.  This  treatment  will  remove  most  of  the  cutch,  which  otherwise 
is  difficult  to  eliminate.  The  sample  is  then  thoroughly  rinsed  in  hot 
and  cold  water,  dried  and  conditioned  in  the  air,  and  weighed.  The 
sample  is  then  incinerated  to  a  complete  ash  to  obtain  the  mineral  matter. 

Moyret  recommends  the  following  method  for  the  analysis  of  weighted 
silks : 

(a)  Moisture. — This  is  best  determined  in  a  proper  conditioning  oven,  but  if  this 
is  not  available  it  is  sufficient  to  dry  10  grams  of  the  silk  in  an  oven  at  110°  C.  for 
one  hour,  or  untU  constant  weight  is  obtained.  If  the  loss  exceeds  15  percent  it  may 
be  assumed  that  the  silk  has  been  weighted  with  hygroscopic  substances. 

(6)  Soluble  Matters. — The  dried  sample  is  boiled  in  distilled  water,  mixed,  dried, 
and  weighed.  Such  substances  as  glycerol,  sugar,  magnesium  sulfate,  potassium 
sulfate,  etc.,  will  pass  into  solution,  and  the  loss  in  weight  will  represent  soluble  matters. 

(c)  Extract  xcith  Petroleum  Ether. — The  sample  is  extracted  for  twenty  minutes  with 
petroleum,  dried,  and  weighed.  Loss  in  weight  represents  extractive  matters.  The 
extract  may  be  evaporated  and  examined. 

(d)  Action  of  H ydrochloHc  Acid. — The  sample  is  treated  for  fifteen  minutes  at 
100°  F.,  with  dilute  (1  :  2)  hydrochloric  acid.  If  ferric  tannate  has  been  used  for 
weighting,  the  silk  will  become  decolorised  and  the  acid  liquid  will  have  a  dirty  bro^Ti 
color  which  does  not  turn  violet  on  the  addition  of  lime-water.  Should  the  reddish 
solution  turn  violet  with  this  latter  reagent,  logwood  is  indicated;  while  if  the  fiber 
becomes  dark  green  and  the  Hquid  yellow  and  machanged  by  hme-water,  Berlin  blue 
is  present.  If  the  fiber  is  green  and  the  Uquid  red,  changing  to  violet  with  addition 
of  lime-water,  it  indicates  logwood  black  dyed  on  a  ground  of  Berhn  blue.  Iron, 
chrome,  and  alumina  mordants  must  be  tested  for  in  the  solution. 

(e)  Action  of  Alkalies. — The  silk  is  next  boiled  in  a  dilute  solution  of  soda  ash, 
which  will  dissolve  the  tannin  from  the  fiber.  The  tannin  may  be  detected  by  addition 
of  iron  salts  to  the  alkaline  solution. 

(/)  Estituatioy}  of  Ash.— A  weighed  sample  of  the  silk  is  ignited  in  a  crucible 
(platinum  preferred).  If  the  weight  is  more  than  1  percent  it  indicates  that  the  silk 
has  been  weighted,  and  the  ash  should  be  further  examined. 

A  method  for  the  determination  of  the  weighting  on  silk  which  appears 
to   be   capable   of    yielding    very    good    results    is    that    suggested    by 


970  TESTING  OF  TEXTILE  FABRICS 

Gnehm.^  It  depends  on  the  fact  that  the  silk  fiber  does  not  appear  to  be 
injured  by  treatment  with  either  hydrofliiosihcic  acid  or  hydrofluoric  acid. 
The  method  is  carried  out  as  follows :  About  2  grams  of  the  silk  to  be  tested 
are  immersed,  with  frequent  stirring,  for  one  hour  at  the  ordinary  tempera- 
ture of  100  cc.  of  a  5  percent  solution  of  hydrofluosilicic  acid.  The  treat- 
ment is  then  repeated  with  100  cc.  of  fresh  acid  of  the  same  strength. 
The  silk  is  then  washed  several  times  with  distilled  water  and  dried.  The 
loss  in  weight  corresponds  to  the  amount  of  inorganic  weighting  materials 
present.  This  method  serves  verj^  well  with  silk  weighted  with  stannic 
phosphate  and  silicate,  but  does  not  appear  to  be  suitable  for  the  estimation 
of  weighting  on  black-dyed  silks  containing  iron  salts.  It  is  said  that 
oxalic  acid  may  also  be  used,-  for  the  purpose  of  removing  the  inorganic 
weighting  materials  from  silks,  without  injury  to  the  silk  fiber  itself. 

Zell  describes  a  method  as  follows:  A  sample  of  1  to  2  grams  of  the 
silk  is  immersed  in  water  for  five  minutes  at  80°  to  100°  C,  then  treated 
for  fifteen  to  twenty  minutes  at  50°  to  60°  C.  with  a  1^  percent  solution 
of  hydrofluoric  acid  contained  in  a  copper  vessel.  The  sample  is  then 
pressed  between  filter  papers,  treated  for  fifteen  minutes  at  50°  to  60°  C. 
with  a  5  percent  solution  of  hydrochloric  acid,  washed  in  warm  water, 
boiled  for  fifteen  minutes  in  a  3  percent  soap  bath,  treated  for  fifteen 
minutes  in  a  warm  soda  bath,  and  rinsed  in  boiling  distilled  water. 

Gnehm  and  Diirsteler  ^  give  the  following  rapid  extraction  methods 
for  the  analysis  of  weighted  silks: 

(a)  For  White  or  Colored  Silks. — The  sample  is  twice  extracted  for  fifteen  minutes 
with  hydrofluoric  acid  of  1  to  2  percent  strength  at  50°-60°  C.  In  the  case  of  silk 
weighted  with  tin  silicate  and  phosphate  the  material  may  be  treated  with  dilute 
hydrochloric  acid  and  hydrogen  sulfide  at  70°-80°  C.  for  thirty  minutes,  then  for 
five  minutes  with  a  4  percent  solution  of  sodium  sulfide  at  40°-50°  C,  and  lastly  for 
fifteen  minutes  with  a  2  percent  solution  of  sodium  carbonate  at  60°-70°  C.  The 
residue  after  this  treatment  may  be  weighed  as  pure  silk  fibroine.  If  aluminium  com- 
pounds are  present  in  the  weighting  these  extractions  must  be  repeated. 

(6)  For  Black  Silks. — If  the  weighting  material  is  tin  phosphate  alone,  extract 
with  hydrofluoric  acid  (1-2  percent  solution),  and  follow  by  a  treatment  with  a  2  percent 
solution  of  sodium  carbonate.  In  the  presence  of  iron  compounds  it  is  best  to  extract 
the  silk  with  a  1  percent  solution  of  hydrochloric  acid,  then  with  a  4  percent  solution 
of  sodium  sulfide,  and  finally  with  a  2  percent  solution  of  sodium  carbonate. 

Taking  all  things  into  consideration,  the  author  considers  the  following 
method  to  be  the  one  best  adapted  for  the  commercial  analysis  of  tin- 
weighted  silks:  A  portion  (about  0.5  gram)  of  the  sample  is  placed  in  a 
weighing-bottle  and  dried  in  an  air-bath  at  105°  C.  to  constant  weight. 
It  is  then  boiled  in  a  2  parcent  solution  of  hydrofluoric  acid  for  five  minutes, 

1  Zeits.  Farben-  u.  Text.  Chem.,  1903,  p.  209. 

2  Muller,  Zeits.  Farben-  u.  Text.  Chem.,  1903,  p.  160. 
^  Farber.  Zeit.,  1906,  p.  218. 


CALCULATIONS  IN  SILK  WEIGHTING  971 

rinsed  with  water,  and  boiled  for  five  minutes  in  a  2  percent  solution  of 
soda  ash  and  washed.  This  alternate  treatment  with  the  hydrofluoric  acid 
and  soda  ash  solutions  is  repeated  three  times,  after  which  the  sample  is 
finally  rinsed,  dried  at  105°  C,  and  reweighed.  The  loss  in  weight  will 
represent  weighting  materials.  The  hydrofluoric  acid  may  be  prepared 
by  diluting  11  cc.  of  commercial  hydrofluoric  acid  to  400  cc,  with  water, 
and  the  soda  ash  solution  by  dissolving  2  grams  of  sodium  carbonate  in 
100  cc.  of  water.  Three  alternate  treatments  with  these  reagents  wiU 
generally  suffice  to  remove  all  weighting  materials  without  appreciable 
injury  to  the  silk  fiber,  though  to  be  accurate  the  treatments  should  be 
repeated  until  no  further  loss  in  weight  is  observed.  This  method  gives 
good  results  if  the  weighting  consists  of  tin-phosphate-silicate.  For  black 
silks  heavily  weighted  with  iron  salts,  and  especially  if  Prussian  blue  is 
present  in  any  considerable  amount,  the  results  will  be  low,  and  it  is 
recommended  to  employ  the  Kjeldahl  nitrogen  method  as  described  in  the 
foregoing  pages. 

After  carefully  testing  out  the  hydrofluoric  method  under  varying  con- 
ditions, the  U.  S.  Testing  Co.  adopted  the  following  procedure  for  the 
determination  of  the  weighting  on  tin  weighted  silk: 

A.  1.  Dry  sample  for  two  hours  at  105°  C.  and  weigh.     (Bone-dry  weight  of  sample 

should  be  between  1  and  2  grams.) 

2.  Boil  sample  in  250  cc.  distilled  water  for  at  least  thirty  minutes.     (This  step 

removes  water-soluble  finishing  materials.) 

3.  Dry  sample  at  105°  C.  to  constant  weight.     The  loss  in  weight  represents  the 

amount  of  water-soluble  finishing  materials.  (The  above  preliminary  process 
is  essential  for  practically  all  commercial  samples,  which  usually  contain 
2  percent  to  10  percent  of  finishing  materials.) 

B.  1.  Warm  100  cc.  hydrofluoric  acid  solution  (approximately  2  percent)  to  60°  C. 

Immerse  sample  and  work  it  in  the  bath  for  twenty  minutes,  not  allowing  the 
temperature  to  exceed  75°  C.  at  any  time.  (It  is  safer  to  keep  the  tempera- 
ture between  60°  and  70°  C.  for  the  entire  time  of  stripping.) 

2.  After  rinsing  the  acid-treated  sample  in  water,  immerse  it  in  a  bath  of  soda 

ash  (approximatelj^  2  percent)  held  at  60°-65°  C.  Work  sample  as  before  and 
remove  at  end  of  twenty  minutes. 

3.  Sample  is  thoroughly  rinsed  and  dried  to  constant  weight  at  105°  C.     The  loss 

by  this  operation  represents  the  amount  of  tin  weighting  in  the  sample. 

C.  1.  Determine  the  amount  of  residual  mineral  matter  in  the  silk  after  the  pre- 

ceding treatment,  by  the  usual  ash  method,  i.e.,  burning  ofT  all  organic  matter. 
(This  final  step  should  be  carried  out  in  all  cases  to  check  up  the  completeness 
of  the  stripping  operations.) 

5.  Calculations  in  Silk  Weighting. — The  amount  of  weighting  on  silk 
is  usually  calculated  on  a  basis  of  ounces  per  pound  of  raw  silk,  and  ex- 
pressed between  a  limiting  variation  of  2  ozs.;  and  it  is  further  reckoned 
that  1  lb.  of  raw  silk  is  equivalent  to  12.4  ozs.  of  pure  silk  fiber  (boiled-off"). 
A  sample  of  silk  described  as  22/24,  for  example,  would  mean  that  22  to 
24  ozs.  of  such  silk  would  be  equivalent  to  16  ozs.  of  raw  silk.     The  amount 


972 


TESTING   OF   TEXTILE   FABRICS 


of  weighting  as  determined  by  the  chemist  should  be  calculated  to  percent- 
age on  the  actual  silk  present,  and  then  by  use  of  the  following  table  the 
corresponding  ounces  may  be  found : 


Percent 
Weighting. 

Ounces. 

Percent 
Weighting. 

Ounces. 

0-  13 
13-  29 
29-  45 
45-  61 
61-  77 
77-  93 
93-109 
109-125 
125-142 

12/14 
14/16 
16/18 

18/20 
20/22 
22/24 
24/26 
26/28 
28/30 

142-158 
158-174 
174-190 
190-206 
206-222 
222-238 
238-254 
254-270 
270 

30/32 
32/34 
34/36 

36/38 
38/40 
40/42 
42/44 
44/46 
46/48 

For  example:  A  sample  of  silk  dried  at  105°  C.  to  constant  weight  proved  to  be 
0.45  gram.  After  treatments  with  hydrofluoric  acid  and  soda  ash  solutions  as  above 
described,  dried  again  at  105°  C,  and  reweighed,  gave  0.31  gram  of  silk  as  a  residue. 
Hence, 

0.45  gram  =  weighted  silk; 

0.31     "     =  pure  silk; 


and 


0.14    "     =  weighting, 
0.14X100 


0.31 


=  45  percent  weighting. 


calculated  from  a  basis  of  pure  silk.     By  reference  to  the  foregoing  table,  it  is  seen 
that  45  percent  weighting  corresponds  to  18/20  ozs. 

If  the  percentage  calculation  for  the  weighting  is  made  on  a  basis  of 
the  weighted  silk  instead  of  the  pure  silk,  the  following  table  is  to  be  used : 


Percent 

Percent 

Ounces. 

Ounces 

Weighting. 

Weighting. 

0-11 

12/14 

59-61 

30/32 

11-22 

14/16 

61-64 

32/34 

22-31 

16/18 

64-66 

34/36 

31-38 

18/20 

66-67.5 

36/38 

38-44 

20/22 

67.5-69 

38/40 

44-48 

22/24 

69-70.5 

40/42 

48-52 

24/26 

70.5-72 

42/44 

52-56 

26/28 

72-73 

44/46 

56-59 

28/30 

73-74 

46/48 

CALCULATIONS  IN  SILK  WEIGHTING  973 

In  the  example  given  above,  the  calculation  would  be 

0.14X100 

— Q-jF —  =  31  percent  weighting 

on  the  basis  of  the  weighted  silk.     By  reference  to  the  table  this  is  seen 
to  correspond  to  18/20  ozs. 

As  the  silk  fiber  is  very  uniform  in  its  structure  and  weight  for  any 
given  length,  an  empirical  method  for  determining  the  weighting  on  silk 
is  as  follows:  The  size  of  a  cocoon-thread  (boiled-off)  averages  2j  denier; 
that  is  to  say,  500  meters  of  such  a  filament  will  average  0.125  gram  in 
weight.  Hence,  if  yarn  is  being  tested,  a  sample  is  observed  under  the 
microscope  and  the  number  of  individual  filaments  present  is  counted. 
A  convenient  length  of  the  yarn  is  then  taken  and  weighed,  and  from  this 
the  weight  of  500  meters  is  calculated.  As  there  are  two  single  filaments 
to  a  cocoon  thread,  by  multiplying  the  number  of  filaments  observed  by 
the  factor  0.0625,  we  obtain  the  weight  of  500  meters  of  the  yarn  as  pure 
silk.  The  difference  between  this  weight  and  the  former  represents  weight- 
ing, from  which  the  percentage  and  ounces  of  weighting  may  be  calculated 
as  given  in  the  foregoing  paragraphs. 

For  example:  A  portion  of  a  single  thread  from  a  skein  of  silk  yarn  was  carefully 
teased  out  so  as  to  separate  the  individual  filaments,  and  these  were  counted  under  a 
microscope.  A  series  of  three  observations  gave  19,  17  and  20  filaments,  or  a  mean 
of  18.6.     The  weight  of  50  meters  of  the  silk  was  0.1312  gram.     Hence 

0.1312X10     =1.312  grams  =  weight  of  500  meters  of  weighted  silk; 

0.0625  X 18 .6  =  1 .  162      "     =  weight  of  500  meters  of  pure  silk; 


0.150      "     =  weighting, 

and 

0.150X100 

— -— —  =  12.2  percent  weightmg, 

and  this  is  equivalent  to  14/16  ozs. 

In  case  the  sample  to  be  examined  is  a  woven  fabric,  it  will  be  neces- 
sary to  pick  apart  the  warp-  and  weft-threads,  and  make  separate  counts 
of  the  filaments  in  each;  then  definite  lengths  of  these  threads  may  be 
measured  off  and  weighed,  and  th°  calculation  conducted  as  before.  In 
making  the  count  of  the  filaments  in  each  thread  of  silk,  the  latter  should 
be  teased  out  as  carefully  as  possible,  in  order  to  separate  the  individual 
filaments.  This  may  readily  be  done  by  laying  the  thread  on  a  glass 
microscope  slide  slightly  moistened  with  water  and  separating  the  fila- 
ments with  a  needle.  The  number  of  filaments  may  then  be  counted 
through  the  microscope,  using  a  low  magnification.  The  count  may  also 
be  made  with  the  aid  of  a  good  magnifying-glass,  but  with  more  difficulty 


974  TESTING   OF  TEXTILE   FABRICS 

and  less  accuracy  than  when  a  microscope  is  employed.  At  least  three 
separate  counts  of  different  threads  should  be  made,  and  the  average  of 
these  taken  as  the  true  number. 

In  case  the  length  of  the  silk  threads  is  measured  in  yards  and  not 
meters,  a  convenient  amount  to  take  for  a  test  is  20  yds.,  then  the  following 
formula  will  hold : 

Let 

A  =  weight  of  500  meters  of  the  weighted  silk=weight  of  20  yds.X27.3; 

B  =  weight  of  500  meters  of  pure  silk  =  number  of  filaments  X 0.0625, 
and 

A  —B 

XlOO=percent  of  weighting. 

A 

The  above  formula  is  for  weights  expressed  in  grams;  in  case  the  weights  employed 
are  grains,  we  have 

A  =  weight  of  20  yds.  X 27 .3; 

B  =  number  of  filaments  X 0.956, 
and 

A—B 

X 100  =  percent  of  weighting. 

A 

These  formulas  may  be  simplified  as  follows: 

(a)  In  case  gram  weights  are  used 

u'  =  weight  of  20  yds.  of  the  silk; 

n  =  number  of  filaments; 

436w  — 71  .       .  ,    . 

— —  X 100=  percent  of  weigh tmg. 

w 

(b)  In  case  grain  weights  are  used 

28.4«;-n        ^  ,      .  ,    . 

X 100  =  percent  of  weightmg. 

w 

The  accuracy  of  this  method  for  determining  the  degree  of  weighting 
of  silk  is  based  on  the  theory  that  the  fiber  is  very  uniform  in  size,  and 
hence  the  weight  of  a  given  length  of  fiber  may  be  assumed  as  being 
constant.  This,  however,  is  only  true  within  certain  limits  and  with 
respect  to  certain  grades  of  silk.  By  reference  to  the  table  in  Chapter 
VI,  it  will  be  seen  that  the  variation  in  size  (or  weight  for  a  given  length) 
of  silks  from  different  countries  is  quite  considerable;  hence,  to  apply 
the  foregoing  method  properly,  the  origin  of  the  silk  should  be  known. 
In  the  case  of  tussah  or  other  varieties  of  wild  silk  the  variation  in  size 
is  much  more  considerable;  hence  the  limit  of  error  in  this  method  is 
much  larger  and  the  results  are  not  sufficiently  accurate  to  be  at  all 
reliable. 


OIL  AND  GREASE  IN  YARNS  AND  FABRICS  975 

Interesting  comment  on  the  accuracy  of  analysis  of  weighted  silk  is  to  be 
found  in  a  report  by  a  committee  of  the  Silk  Association  of  America  (1914). 
This  committee  had  an  exhaustive  series  of  tests  made  by  the  U.  S.  Bureau 
of  Standards,  by  a  chemist  of  Yale  University,  the  chemists  of  the  two 
most  prominent  silk  dyeing  firms,  by  a  German  chemist,  and  by  the 
chemist  of  a  leading  silk  manufacturer,  in  order  to  determine  with  what 
degree  of  accuracy  such  tests  could  be  made.  Results  showed  that  in 
the  analyses  of  various  samples  of  silk  goods  where  the  actual  percentage 
of  weighting  was  known,  the  amounts  returned  by  the  various  chemists 
di:Pfered  considerably,  especially  in  the  case  of  black  silks.  The  analyses 
made  on  the  tin-weighted  silks  agreed  much  more  closely,  but  when  the 
weighting  used  was  other  than  metallic  or  was  a  mixture  of  metallic  and 
vegetable  materials,  very  inaccurate  results  were  obtained.  This  was 
especially  true  of  the  class  of  fabrics  commercially  known  as  "  tailoring 
dyes." 

6.  Oil  and  Grease  in  Yams  and  Fabrics. — An  estimination  of  the 
amount  of  oil  and  grease  is  frequently  required  for  woolen  or  worsted 
cloth,  yarn,  tops,  roving,  etc.  A  method  leading  to  approximate  results, 
which  are  generally  sufficiently  accurate  for  commercial  purposes,  is  to 
weigh  ofT  a  sample  of  the  material  to  be  tested  and  scour  it  for  thirty 
minutes  in  a  solution  containing  5  grams  of  good  quality  soap  per  liter 
at  a  temperature  of  140°  F.  It  is  then  rinsed  well  in  warm  water  a  couple 
of  times  to  remove  all  of  the  soapy  liquor,  and  then  dried.  Before 
reweighing  it  should  be  left  in  the  air  for  about  an  hour,  so  as  to  come  to 
the  same  hygroscopic  condition  as  when  first  weighed.  The  loss  in  weight 
will  represent  the  oil,  grease,  and  any  dirt  in  the  fiber,  and  may  be  called 
the  "  scouring  loss." 

A  more  accurate  method  to  determine  the  oi'  and  grease  is  to  weigh 
off  about  5  grams  of  the  material  and  agitate  in  a  flask  with  about  100  cc. 
of  petroleum  ether  for  twenty  minutes.  This  will  dissolve  all  oily  matters 
present,  and  the  liquid  may  be  poured  into  a  weighed  evaporating-dish. 
The  residual  fiber  is  washed  with  about  100  cc.  more  of  petroleum  ether; 
the  latter  is  added  to  the  first  extraction  and  the  whole  evaporated  to 
dryness  on  a  water-bath,  and  the  weight  of  the  residue  of  oil  in  the 
evaporating-dish  is  determined,  or  the  extracted  fiber  may  be  removed 
from  the  flask,  dried,  exposed  to  the  air  for  an  hour  and  reweighed,  and  the 
loss  in  weight  will  represent  grease  and  oil. 

In  the  two  preceding  methods  where  the  air-dry  weights  are  used, 
care  should  be  especially  taken  to  weigh  the  material  before  and  after 
under  the  same  hj-groscopic  conditions,  otherwise  considerable  variations 
in  results  may  be  obtained  by  reason  of  the  fiber  absorbing  a  greater  or 
less  quantity  of  moisture;  where  accurate  results  are  demanded,  it  will 
be  necessary  to  make  three  weighings,  as  follows:    (a)  the  weight  of  the 


976 


TESTING  OF  TEXTILE  FABRICS 


air-dry  material,  (6)  the  weight  of  the  material  after  drying  at  105°  C. 
for  one  hour,  (c)  the  weight  of  the  extracted  material  after  drying  for  one 
hour  at  105°  C.  In  this  manner  the  somewhat  uncertain  factor  of  moisture 
is  eliminated.  The  percentage  of  grease  in  the  matrial,  however,  should 
be  calculated  on  the  weight  of  the  air-dry  fiber. 

For  example:  A  sample  of  woolen  yarn  weighing  5.026  grams  was  dried  at  105°  C. 
for  one  hour  and  when  weighed  again  gave  4.516  grams;  after  extraction  with  petroleimi 
ether  and  drying  again  as  before,  it  weighed  4.271  grams.  The  amount  of  grease  in 
this  case  was  therefore  4.516-4.271  =0.245  gram  or  (0.245X100)  -f- 5.026  =  4.67  percent. 

A  still  better  and  more  accurate  method  for  the  determination  of 
grease  is  to  treat  a  weighed  sample  of  the  material  in  a  Soxhlet  extraction 

apparatus  with  petroleum  ether, 
evaporating  off  the  solvent  and 
weighing  the  residue  of  grease. 
The  analysis  is  determined  as  fol- 
lows: The  small  flask  of  the  ap- 
paratus is  weighed  and  then  about 
half-filled  with  petroleum  ether 
(about  50  to  75  cc);  about  2 
grams  of  the  material  to  be  ex- 
tracted is  accurately  weighed  and 
placed  in  the  extraction  tube  or 
capsule,  after  which  the  several 
parts  of  the  apparatus  are  con- 
nected and  the  flask  is  heated  on 
a  water-bath  until  all  the  oil  or 
grease  has  been  extracted  and 
dissolved  by  the  petroleum  ether. 
According  to  the  form  of  apparatus 
employed,  this  may  require  from 
twenty  minutes  to  one  hour.  The 
flask  is  then  removed  and  the  sol- 
vent is  distilled  off.  The  residual 
grease  in  the  flask  is  then  dried 
for  one-half  hour  on  the  water- 
g  f^  bath   and   after  cooling  weighed. 

Fig.  409.— Apparatus  for  Testing  Amount  of  The    increase    in    the    weight    of 
Oil  in  Tops  or  Other  Textiles.  the   flask   represents    the   amount 

of  grease. 

E.  W.  Tetley  (Textile  Manufacturer)  gives  the  following  method  for 

testing   the   amount   of   oil   contained   in   worsted   tops.     A   recognised 

standard  for  oil-combed  tops  is  3^  percent  by  this  test,  3  percent  being 

added  oil,  h  percent  being  the  natural  fat  contained.     A  flask  of  500  cc. 


OIL  AND  GREASE  IN  YARNS  AND  FABRICS  977 

capacity  is  taken,  and  5  grams  of  top,  carefully  weighed,  placed  therein. 
Three  hundred  cc.  of  petroleum  spirit  is  then  poured  into  the  flask,  this 
quantity  covering  the  material.  It  is  left,  say,  a  day,  being  shaken  at 
intervals,  the  solvent  during  that  time  thoroughly  absorbing  all  the  fatty 
matter.  Then  100  cc.  is  carefully  poured  off  into  an  evaporating  dish 
of  known  weight,  the  dish  being  placed  over  a  water-bath  and  the  spirit 
evaporated.  The  use  of  the  water-bath  is  to  evaporate  the  spirit  at 
steam  heat,  and  a  handy  way  is  to  have  the  water  in  a  beaker,  and  place 
the  dish  on  top  of  it,  the  steam  from  the  boiling  water  heating  the  dish 
sufficiently.  The  sketch  (Fig.  409  A)  shows  the  arrangement.  After 
the  solvent  has  quite  evaporated,  the  dish  is  placed  in  a  drying-oven  at 
100°  F,  for  one  hour,  taken  out,  and  allowed  to  cool.  The  dish  and 
contents  are  then  weighed,  the  increase  in  weight  representing  the  total 
fat  absorbed  by  the  100  cc.  of  solvent,  which,  multiplied  by  3,  gives  total 
fat  in  300  cc. — i.e.,  in  the  5  grams  of  "  top."  The  percentage  may  be 
then  calculated  thus: 

Weight  of  evaporating  dish =  54 .  52  grams 

Weight  of  dish+residue  after  experiment =54.57      " 

.-.  Weight  of  oil  in  100  cc =  0.05      " 

.*.   Weight  of  oil  in  300  cc,  or  in  5  grams  of  top.  =   0. 15      " 

100X0.15 
.*.   Percent  oil  on  top  = =  3        percent 

If  a  very  accurate  result  is  desired,  the  use  of  the  Soxhlet  apparatus 
illustrated  (Fig.  409  B)  is  necessary.  A  flask  (A)  of  known  weight  is 
taken  and  placed  over  a  water-bath,  the  flask  being  about  half-filled  with 
ether.  Through  the  cork  of  the  flask  is  fitted  the  lower  end  of  the  extractor 
{B,  C).  Through  the  cork  at  the  top  of  the  extractor  is  fitted  the  tube  (D) 
leading  to  the  condenser  {E)  as  shown.  By  means  of  retort  stands  the 
whole  apparatus  can  be  made  quite  firm.  The  material  to  be  tested  is 
weighed  carefully  and  placed  in  the  widened  tube  of  the  extractor  (which 
is  quite  separate  from  the  lower  narrow  tube)  to  about  the  height  shown 
by  the  shaded  portion.  By  means  of  a  Bunsen  burner,  the  ether  is  evap- 
orated, the  vapor  passing  up  through  the  lower  tube,  then  to  the  left 
through  side  tube  (Z),  and  thence  into  the  upper  portion  of  the  extractor, 
from  which  it  passes  into  the  Liebig  condenser.  This  condenser,  being 
surrounded  by  a  jacket  of  constantly  changing  cold  water,  condenses  the 
vapor,  which  returns  into  the  extractor  thus,  and  drops  down  on  to  the 
material,  through  which  it  percolates,  when,  having  become  saturated 
with  the  fat,  it  finds  an  outlet  in  the  syphon  tube  (  Y).  When  the  con- 
densed ether  in  the  extractor  reaches  to  the  height  of  the  top  of  the  syphon 
tube,  it  syphons  over,  passes  down  the  tube,  and  returns  into  the  flask 
in  the  manner  shown.     In  this  way  the  ether  returns  to  the  flask,  having 


978 


TESTING   OF   TEXTILE   FABRICS 


on  its  way  absorbed  the  fat  from  the  materiah  The  operation  must  be 
continued  until  the  returning  ether  is  pure,  this  resulting  as  a  rule  after 
it  has  syphoned  over  about  ten  times.  The  flask  is  then  removed,  the 
ether  evaporated  over  a  water-bath,  and  placed  in  the  oven  to  dry  until 
the  weight  becomes  constant.  The  increased  weight  of  the  flask  will  give 
the  amount  of  oil  or  fat  which  was  contained  in  the  sample,  from  which 
the  percentage  can  be  reckoned.  It .  should  be  noted  that  the  corks  should 
not  be  of  rubber,  and  should  be  free  from  grease  and  dirt,  which  may  be 
extracted,  if  necessary,  in  ether. 

7.  Estimation  of  Finishing  Materials  on  Fabrics. — Cotton  fabrics  are 
quite  generally  sized  or  otherwise  finished  for  the  purpose  of  giving  the 
cloth  a  better  handle  or  a  greater  weight.  For  this  purpose  a  wide  variety 
of  substances  may  be  used,  but  starch  is  nearly  always  the  basis  of  the 
sizing.  Soaps,  fats,  gelatine,  vegetable  mucilages,  resin,  and  China  clay 
are  also  of  common  occurrence.  In  some  cases  hygroscopic  salts,  such  as 
calcium  chloride,  magnesium  chloride,  or  zinc  chloride  are  used  to  obtain 
certain  effects  or  to  increase  the  weight  of  the  goods.  Woolen  goods  are 
sometimes  sized  or  weighted  in  a  similar  manner,  both  for  purposes  of 
reducing  certain  finishes  and  of  fraudulently  increasing  the  weight  of  the 
fabric. 

Thompson  ^  gives  the  following  typical  analyses  of  cotton  fabrics: 


I. 

11. 

III. 

IV. 

V. 

VI. 

Percent. 

Percent. 

Percent. 

Percent. 

Percent 

Percent. 

Material: 

Fiber              

47.29 
4.11 

53.02 
4.61 

60.75 

5.28 

70.84 
6.16 

80.51 
7.02 

81.78 

Normal  moisture 

7.11 

Weight  of  cloth 

Dressing : 

Water 

Dressing  and  fat 

51.40 

6.01 
12.77 

29.82 

57.63 

5.02 
13.36 
23.99 

66.03 

4.65 
13.33 
15.99 

77.00 

3.07 

12.43 

7.50 

87.53 

2.01 
8.30 
2.16 

88.89 

2.89 
3.33 

Mineral  matter 

4.89 

Weight  of  dressing 

48.60 

42.37 

33.97 

23.00 

12.47 

11.11 

According  to  Hoyer  cotton  cloth  in  the  gray  or  unbleached  state 
should  consist  approximately  of  83  percent  fiber,  7  percent  moisture, 
8.5  percent  of  starch  and  fatty  matters  (used  for  softening  the  yarn  and 
sizing  the  warp),  and  1.5  percent  of  ash.  After  boiling-out  and  bleaching, 
however,  only  78  percent  of  fiber  is  left,  so  that  by  the  addition  of  dressing 
*  Sizing  of  Cotton  Goods,  p.  150. 


ESTIMATION   OF   FINISHING   MATERIALS   IN   FABRICS  979 

the  finished  cloth  consists  of  78  percent  fiber,  7  percent  moisture,  7  percent 
starch,  and  7.5  percent  mineral  matter.  If  the  amount  of  fiber  falls 
below  78  percent  in  bleached  calico  or  much  below  83  percent  in  gray 
calico,  it  may  be  supposed  that  the  cloth  is  loaded. 

Linen  fabrics  should  contain  but  a  small  amount  of  finishing  or  dressing 
materials.  Usually  a  small  quantity  of  starch  is  required  for  the  purpose 
of  sizing  the  warps,  but  no  mineral  matter  should  be  present  beyond 
that  to  be  found  in  the  natural  fiber  itself.  Linen  cloth  should  not  lose 
more  than  5  percent  when  boiled  in  water. 

Woolen  goods  are  often  finished  with  Irish  moss,  glue,  gelatine,  dextrine, 
starch,  albumen,  sodium  silicate,  etc. 

In  the  finishing  of  silk  fabrics  gelatine,  tragacanth,  gum  arabic,  shellac, 
etc.,  are  used. 

The  following  is  a  brief  and  general  survey  of  the  determination  of 
finishing  materials  on  textile  fabrics: 

(a)  Moisture  is  determined  in  the  usual  manner  as  described  above. 
If  the  amount  of  moisture  is  large  a  high  degree  of  weighting  or  finish 
may  be  suspected,  especially  in  the  case  of  cotton  goods,  since  starch 
absorbs  much  more  water  than  the  pure  cotton  fiber. 

(6)  Benzene  Extract. — The  dried  sample  is  extracted  in  a  Soxhlet  with 
benzene.  This  will  dissolve  out  fats,  rosin,  wax,  paraffin,  etc.  The 
extract  is  distilled  and  the  amount  of  solid  residue  determined. 

(c)  Water  Extract. — The  sample  is  then  boiled  in  water  for  one  hour, 
which  will  remove  dextrine,  starch,  glue,  gum  arabic,  sugar,  Irish  moss, 
tragacanth,  etc.,  as  well  as  various  insoluble  matters  such  as  talc,  China 
clay,  etc.,  which  are  held  on  the  fiber  by  the  various  finishes.  The  water 
extract  is  filtered,  and  the  solution  may  then  be  examined  for  the  various 
ingredients. 

(d)  Mineral  Matters. — These  may  be  determined  by  igniting  a  weighed 
sample  of  the  fabric  to  a  complete  ash.  The  ash  may  further  be  tested  in 
order  to  determine  its  various  ingredients. 

Prior  gives  the  following  method  for  testing  the  ash  of  textile  fabrics: 
A  portion  of  the  ash  is  boiled  with  nitric  acid  and  a  strong  effervescence  will 
indicate  the  presence  of  metallic  carbonates.  The  solution  is  evaporated  to 
dryness  on  a  water-bath,  taken  up  with  nitric  acid  and  water,  any  insoluble 
residue  filtered  off,  and  the  filtrate  treated  with  hydrogen  sulfide.  A 
black  precipitate  will  indicate  the  presence  of  lead.  This  should  be 
filtered  off,  dissolved  in  nitric  acid,  and  tested  with  sulfuric  acid,  potassium 
chromate  or  other  reagents  to  confirm  the  presence  of  lead.  The  filtrate 
is  tested  for  iron  by  neutralising  with  ammonia  and  adding  ammonium 
sulfide.  The  filtrate  from  this  precipitate  is  tested  for  barium,  calcium, 
and  magnesium  by  acidulating  with  hydrochloric  acid,  boiling  to  expel 
the   liberated   hydrogen    sulfide,    then   neutralising   with   ammonia   and 


980  TESTING  OF  TEXTILE   FABRICS 

adding  ammonium  chloride  and  carbonate.  Any  precipitate  is  filtered  off, 
washed,  and  dissolved  in  dilute  hydrochloric  acid  and  this  solution  is 
tested  by  the  addition  of  calcium  sulfate  solutions.  Immediate  precipitate 
indicates  the  presence  of  barium.  Another  portion  of  this  filtrate  is 
tested  with  ammonium  oxalate  solution  when  a  precipitate  will  indicate 
the  presence  of  calcium.  The  ash  which  is  insoluble  in  nitric  acid  may 
contain  silica  resulting  from  the  decomposition  of  magnesium  silicate  or 
sodium  silicate  together  with  barium  sulfate,  tin  oxide,  gypsum,  or  clay. 
This  residue  is  boiled  with  sodium  carbonate  which  will  dissolve  the 
silicate  and  decompose  the  gypsum.  After  filtration,  the  precipitate  is 
washed,  dissolved  in  cold  dilute  hydrochloric  acid  and  tested  for  the 
presence  of  iron  and  calcium  as  above  indicated.  The  filtrate  is  acidulated 
with  hydrochloric  acid,  evaporated  to  dryness,  and  the  residue  is  taken 
up  with  water  and  hydrochloric  acid.  Any  insoluble  residue  of  sihca  is 
separated  and  the  filtrate  is  tested  for  sulfuric  acid  by  the  addition  of 
barium  chloride.  The  residue  which  is  undecomposed  by  sodium  car- 
bonate or  insoluble  in  hydrochloric  acid  may  contain  barium  sulfate,  clay, 
or  tin  oxide.  This  is  fused  with  10  parts  of  sodium  carbonate  in  a  porcelain 
crucible  and  the  melted  mass  is  treated  with  water  and  sodium  bicarbonate 
and  filtered.  The  water  residue  is  next  boiled  with  strong  hydrochloric 
acid  and  the  liquid  treated  with  hydrogen  sulfide.  A  yellow  precipitate 
will  indicate  the  presence  of  tin.  This  is  filtered  off  and  half  the  filtrate 
is  tested  for  aluminium  by  the  addition  of  ammonia,  and  the  other  half 
for  barium  by  the  addition  of  sulfuric  acid.  The  filtrate  from  the  fusion 
is  treated  with  hydrochloric  acid  and  partially  evaporated,  which  will 
throw  out  the  silica.  The  soluble  portion  is  tested  for  the  presence  of 
sulfates  by  the  addition  of  barium  chloride. 

8.  Analysis  of  Bleached  Cotton. — In  the  bleaching  of  cotton  the  main 
object  is  to  remove  all  impurities  from  the  fiber,  leaving  only  the  pure 
cellulose  as  the  resulting  product  without,  however,  disintegrating  and 
weakening  the  structure  of  the  fiber  itseh.  In  the  processes  of  bleaching, 
alkalies,  acids  and  strong  oxidising  agents  are  employed;  hence  there  is 
danger  of  the  formation  of  oxycellulose,  a  condition  which  must  be  avoided 
if  good  bleaching  is  to  be  attained.  The  physical  tests  which  should  be 
applied  to  bleached  cotton  are: 

(1)  Color;  for  which  purpose  a  sample  should  be  examined  in  a  good 
north  light  and  compared  with  a  standard  sample.  There  is  no  absolute 
standard  of  white;    hence  such  a  color  test  must  be  a  comparative  one. 

(2)  Tensile  Strength;  this  should  be  determined  with  reference  to 
both  the  unbleached  and  bleached  samples,  and  any  loss  due  to  the  process 
of  bleaching  is  noted.  This  loss  will  naturally  vary  with  the  nature  of  the 
material  being  bleached.  In  the  case  of  yarns,  the  tensile  strength  is 
generally  somewhat  less  on  bleaching,  but  the  loss  should  not  be  over 


ANALYSIS   OF   BLEACHED   COTTON 


981 


5  percent  when  the  bleaching  is  properly  conducted.  In  the  case  of 
2-ply  yarns  there  is  often  no  appreciable  loss  in  strength  due  to  bleaching. 
In  bleached  cloth  the  loss  in  strength  due  to  bleaching,  if  any,  should 
not  be  over  2  percent.  In  many  cases  there  will  be  a  noticeable  increase 
in  the  strength  of  the  cloth,  due  no  doubt  to  a  shrinking  and  felting 
together  of  the  fibers. 

(3)  Elasticity;  this  factor  is  usually  reduced  to  some  extent  by 
bleaching.  This  is  especially  the  case  where  the  material  is  stretched 
and  pulled  during  the  processes  of  bleaching  and  washing. 

In  this  connection  O'Neill  gives  the  following  interesting  results, 
made  to  determine  the  tensile  strength  of  cotton-threads  before  and  after 
bleaching: 


Average  Weight  Required  to  Break 
a  Single  Thread. 

Before  Bleaching. 

After  Bleaching. 

No   1  cloth,  weft -threads 

1714  grains 
3140      " 
3407      ' ' 
3512      " 

2785  grains 
2020      " 
3708      ' ' 

No.  1     ' '      warp-threads 

No.  2     "                "            

No.  3     "                "            

4025      ' ' 

It  wiU  be  noticed  that  in  two  cases  out  of  three  the  warp-threads  are 
stronger  than  before,  and  it  may  be  safely  concluded  that  the  tensile 
strength  of  cotton  yarn  is  not  injured  by  careful  though  thorough  bleaching, 
and  probably  it  may  be  strengthened  by  the  wetting  and  pressure,  causing 
a  more  complete  and  effective  binding  of  the  separate  cotton  fibers,  the 
twisting  together  of  which  makes  the  yarn  stronger. 

The  chemical  tests  to  be  applied  in  judging  the  quality  of  bleached 
cotton  are  as  foUows: 

(1)  Ash;  this  is  best  determined  by  taking  10  grams  of  the  sample 
clipped  into  small  fragments  and  burning  in  a  porcelain  crucible  until 
a  complete  ash  is  left.  The  weight  of  the  residual  ash  is  calculated  to  a 
percentage  on  the  weight  of  the  sample  taken.  The  ash  of  raw  cotton 
will  average  about  1  percent;  on  boiling  off,  this  amount  will  usually 
be  reduced  to  about  0.25  to  0.35  percent;  and  a  well-bleached  cotton 
should  not  give  more  than  0.10  percent  for  yarns  and  light-weight  fabrics, 
and  0.15  percent  for  heavy-weight  fabrics.  The  manner  and  degree  of 
bleaching,  however,  will  have  much  to  do  with  the  amount  of  ash. 
Cotton  which  has  been  poorly  boiled  out  and  only  partially  bleached 
may  show  a  much  higher  proportion  of  ash;  or  cotton  which  has  been 
thoroughly  bleached  but  not  well  washed,  or  which  has  been  washed  with 


982  TESTING  OF  TEXTILE  FABRICS 

impure  water,  may  also  show  in  ash  as  high  as  0.25  to  0.50  percent.  Cotton 
which  has  been  overbleached  by  the  use  of  too  strong  a  solution  of  bleaching 
powder  will  also  usually  show  a  proportion  of  ash  greater  than  that  which 
is  allowed.  The  determination  of  the  amount  of  ash  is  an  excellent 
control-test  in  ascertaining  the  quality  of  the  bleaching.  A  frequent 
defect  in  the  bleaching  of  cloth  and  knit-fabrics  is  that  caused  by  portions 
of  the  fabric  coming  in  contact  with  strong  solutions  of  the  chemic,  which 
is  subsequently  only  incompletely  removed.  This  results  in  a  discolora- 
tion and  weakening  of  the  goods,  though  the  defect  may  not  become 
apparent  until  after  the  goods  have  been  stored  for  some  months.  In 
all  such  cases  the  amount  of  ash  will  be  abnormally  high  (from  0.25  to 
0.50  percent). 

(2)  Oxycellulose;  when  cotton  is  bleached  with  solutions  of  chloride 
of  lime  there  is  nearly  always  more  or  less  oxycellulose  formed.  This 
is  also  true  when  the  cotton  has  been  improperly  boiled  out  previous 
to  bleaching.  The  presence  of  oxycellulose  to  any  considerable  extent 
in  bleached  cotton  fabrics  leads  to  various  defects,  such  as  tendering 
of  the  fiber,  discoloration  and  improper  and  uneven  absorption  of  dyestuff 
if  the  fabric  is  subsequently  dyed.  There  are  a  number  of  tests  to  show 
the  presence  of  oxycellulose: 

(a)  As  oxycellulose  has  a  greater  attraction  for  certain  basic  dye- 
stuffs  than  ordinary  cotton,  by  staining  the  fabric  with  dilute  solution 
of  Methylene  Blue  the  presence  of  oxycellulose  may  be  detected.  In 
applying  the  test  the  sample  should  be  well  washed,  treated  for  thirty 
minutes  with  cold  dilute  nitric  acid  (2°  Be.),  again  washed,  treated  with 
boiling  sodium  bisulfite  solution  (1°  Be.)  for  fifteen  minutes,  washed, 
treated  with  dilute  hydrochloric  acid  (2°  Be.)  for  thirty  minutes,  and 
finally  washed  with  water.  The  sample  so  prepared  is  then  steeped  for 
twenty  minutes  in  a  xV  percent  solution  of  Methylene  Blue,  rinsed  and 
dried.  Portions  of  the  fabric  which  may  contain  oxycellulose  will  appear 
considerably  darker  in  color. 

(6)  Ordinary  cotton  when  treated  with  an  iodine  solution  gives  a 
yellow  coloration  changed  to  blue  with  sulfuric  acid,  but  oxycellulose 
gives  an  immediate  blue  color  which  is  destroyed  by  sulfuric  acid.^ 

(c)  A  more  satisfactory  test  for  oxycellulose  is  to  heat  the  fabric  for 
fifteen  minutes  with  10  percent  Fehling's  solution  on  the  hot  water-bath. 
After  rinsing  with  water,  red  cuprous  oxide  will  be  found  deposited  wher- 
ever oxycellulose  is  present.  Before  carrying  out  this  test  all  sizing  and 
finishing  compounds  should  be  removed  from  the  sample.  This  test 
may  be  carried  out  in  a  quantitative  manner,  giving  what  is  known  as 
the  "  copper  index."  Proceed  as  follows:  3  grams  of  bleached  cotton 
are  placed  in  a  1|  liter  flask,  and  300  cc.  of  boiling  water  and  50  cc.  of 
1  Vetillart,  Bull.  Soc.  hid.  Rouen,  1883,  p.  233. 


ANALYSIS  OF  BLEACHED  COTTON  983 

Fehling's  solution  added.  The  mixture  is  boiled  for  fifteen  minutes, 
using  a  reflux  condenser  so  as  to  avoid  loss  of  liquid.  Then  filter  and  wash 
until  the  wash-water  is  free  from  copper  salts.  The  cellulose  remains 
on  the  filter  with  the  precipitate  of  cuprous  oxide.  This  is  treated  in  a 
porcelain  dish  with  15  cc.  of  nitric  acid.  The  dissolved  copper  is  filtered 
off,  and  its  amount  may  be  determined  by  electrolysis,  or  quantitatively 
by  the  usual  methods.  This  amount  of  copper  calculated  to  percentage 
on  the  amount  of  cotton  taken  for  analysis  gives  the  copper  index,  and 
measures  the  amount  of  oxycellulose  and  hydrocellulose  present.'  In 
carrying  out  this  test  the  use  of  cork  or  rubber  stoppers  should  be  avoided, 
as  these  will  cause  the  precipitation  of  red  cuprous  oxide.  The  apparatus 
used  should  have  ground  glass  joints. 

(d)  The  sample  is  treated  with  a  dilute  solution  of  Bcnzopurpurine, 
then  rinsed  with  dilute  sulfuric  acid,  and  finally  washed  with  water  until 
the  red  color  of  ordinary  cotton  reappears.  Any  portions  containing 
oxycellulose  will  remain  as  bluish  black  stains. 

(e)  Vieweg  makes  a  determination  of  what  is  termed  the  acid  index,  as 
follows:  3.2  grams  of  the  dried  bleached  cotton  are  boiled  for  fifteen 
minutes  with  50  cc.  of  a  semi-normal  solution  of  caustic  soda.  The  excess 
of  soda  is  then  titrated  with  a  semi-normal  solution  of  sulfuric  acid  using 
phenolphthalein  as  the  indicator.  The  amount  of  caustic  soda  neutralised 
by  the  cotton  calculated  to  a  percentage  basis  gives  the  acid  index,  and 
represents  the  alkali  neutralised  in  decomposing  and  dissolving  the  hydro- 
cellulose  and  oxycellulose  present  in  the  bleached  fiber.  Piest  ^  has 
compared  this  method  with  that  of  the  copper-index  method  of  Schwalbe, 
and  concludes  that  the  latter  factor  is  preferable  as  an  accurate  indication 
of  the  amount  of  oxidised  cellulose  present  in  bleached  fabrics. 

(/)  Another  test  for  oxycellulose  which  is  said  to  be  very  reliable  is  as 
follows:  A  few  drops  of  a  suspension  of  Indanthrene  Yellow  (prepared 
by  dissolving  some  of  the  dried  paste  of  the  dyestuff  in  strong  sulfuric 
acid,  precipitating  by  pouring  into  cold  water,  and  neutralising)  are 
added  to  a  10  percent  solution  of  caustic  soda,  and  the  fabric  to  be  tested 
is  passed  through  the  mixture  and  slightly  squeezed.  The  material  is 
then  held  over  a  beaker  in  which  water  is  vigorously  boiling.  Within  a 
minute  a  deep  blue  stain  appears  wherever  oxycellulose  or  hj^drocellulose 
is  present,  while  the  rest  of  the  fabric,  if  it  has  been  carefully  bleached, 
shows  no  trace  of  blue  for  at  least  five  minutes.  If  the  cotton  is  next 
washed,  soured,  and  scoured  with  soap,  the  unaffected  dye  is  readily 
removed,  but  wherever  oxycellulose  has  formed  the  color  is  firmly  fixed.^ 

According  to  Nanson  the  yellowing  of  bleached  canvas  may  be  due  to 
the  effect  of  heat  or  time  on  (a)  oxycellulose,  (h)  chloramines  formed  by 

1  Schwalbe,  Zeit  angew.  Chem.,  1910,  p.  924.  '  Zcit.  angew.  Chem.,  1910,  p.  1222. 

3  SchoU,  Berichte,  1911,  p.  1312;  and  Ermen. 


984  TESTING  OF  TEXTILE  FABRICS 

the  action  of  chlorine  on  the  albuminoids  of  imperfectly  scoured  cotton, 
or  (c)  the  chloramines  accumulated  in  old  bleaching  liquors. 

The  following  chemical  methods  have  been  proposed  for  the  purpose  of 
estimating  in  a  practical  manner  the  extent  to  which  cotton  has  been 
bleached.  These  analytical  methods  serve  as  a  basis  of  estimating  the 
chemical  condition  of  the  bleached  fiber,  and  many  times  may  form  a 
valuable  means  of  detecting  overbleaching  and  the  presence  of  decomposed 
cellulose. 

(1)  The  so-called  "  wood-gum  value  "  represents  the  substance  soluble 
in  a  5  percent  solution  of  sodium  hydroxide  when  the  cotton  is  left  in 
contact  with  the  solution  for  a  considerable  time  and  without  heating. 
This  "  wood-gum  value  "  is  a  complex  function,  and  includes  small  quan- 
tities of  fats  and  fatty  acids,  gums,  and  a  portion  of  the  products  of  over- 
bleaching.  The  latter  may  be  classified  as  oxycellulose.  The  multiplicity 
of  the  factors  in  this  value  deprives  it  of  the  character  of  an  absolute 
analytical  number,  but  it  serves  as  an  aid  to  determine  the  purity  of  the 
bleached  cellulose.  In  the  case  of  normally  purified  cotton  this  "  wood- 
gum  value  "  lies  between  0.5  and  1.1  percent. 

(2)  The  "  copper  value  "  represents  a  standard  suggested  by  Schwalbe, 
and  is  perhaps  the  most  definite  measure  available  for  the  diagnosis  of  the 
presence  of  any  chemical  modification  in  the  cellulose,  and  particularly 
is  it  indicative  of  over-bleaching.  Normally  purified  cotton  shows  a 
total  "  copper  value  "  considerably  below  2,  and  in  general  it  is  preferable 
that  this  value  should  not  exceed  1;  whereas  the  "copper  value"  of 
strongly  over-bleached  cotton  may  rise  to  as  high  a  figure  as  16.  Hydro- 
cellulose  likewise  shows  an  increased  "  copper  value,"  but  not  nearly  to 
the  same  degree  as  is  the  case  with  oxycellulose. 

(3)  The  "  copper  hydrate  value  "  represents  the  quantity  of  cupric 
hydroxide  absorbed  by  the  bleached  cotton  from  a  cold  Fehling's  solution. 
This  is  regarded  as  indicating  the  state  of  hydration  of  the  cellulose,  and 
consequently  is  especially  pronounced  in  the  case  of  mercerised  cellulose. 
It  is  normal  (that  is  to  say  about  0.5)  in  the  case  of  oxycellulose,  and 
particularly  low  in  the  case  of  hydrocellulose. 

(4)  The  "  acid  value,"  which  has  been  described  by  Vieweg,  represents 
the  amount  of  caustic  soda  which  is  neutralised  by  the  bleached  cellulose 
after  boiling  for  one-half  hour  with  a  1  percent  solution  of  sodium  hydroxide. 
This  is  also  a  complex  function  and  indicates  primarily  the  chemical 
modification  in  the  fiber  due  to  the  formation  of  oxycellulose  and  hydro- 
cellulose  in  approximately  equal  degrees,  and  consequently  it  indicates 
the  specific  susceptibility  of  the  bleached  cellulose  itself  to  the  action 
of  alkaline  hydrolysis.  This  value  is  particularly  low  in  the  case  of 
cellulose  which  has  already  been  treated  with  a  solution  of  strong  caustic 
soda,  such,  for  instance,  as  is  the  case  with  mercerised  cotton,  and  which 
is  not  otherwise  modified  by  any  strong  oxidising  or  acid  treatments  which 


ANALYSIS  OF  BLEACHED  COTTON 


985 


would  increase  the  tendency  of  the  cellulose  in  the  fiber  to  undergo 
hydrolysis. 

(5)  The  "  copper  sulfate  value  "  is  the  quantity  of  cupric  hydroxide 
absorbed  by  the  bleached  fiber  from  a  solution  of  copper  sulfate.  This 
value  has  but  little  diagnostic  importance;,  it  tends  to  be  low  in  the 
case  of  oxidised  cellulose,  but  the  differences  between  this  and  normal 
cellulose  are  really  too  small  for  any  practical  use. 

(6)  The  "  viscosity  test  "  of  Ost  is  a  most  valuable  measure  of  the 
chemical  condition  of  the  bleached  fiber,  but  in  the  case  of  chemically 
modified  cellulose  it  shows  no  distinction  between  the  various  causes  of 
this  modification.  The  test  is  made  by  treating  the  bleached  cotton  in  a 
solution  of  cuprammonium  hydrate  prepared  in  the  manner  described 
by  Ost;  this  cuprammonium  cellulose  solution  is  then  diluted  with  water 
in  a  certain  prescribed  manner  and,  after  standing  for  five  days,  it  should 
show  a  viscosity  of  about  10  in  the  case  of  normally  treated  cotton.  Mer- 
cerised cotton  will  also  show  normal  viscosity,  but  the  prolonged  action  of 
a  mercerised  alkali  solution  will  modify  the  cellulose  as  strongly  as  will 
the  action  of  strong  oxidising  agents  and  acids,  and  this  modification  will 
considerably  affect  the  figure  for  viscosity. 

Amblihl  ^  gives  the  following  method  of  ascertaining  whether  bleaching 
has  been  carried  out  efficiently  and  in  such  a  manner  as  to  preclude  the 
possibihty  of  the  goods  turning  yellow:  (1)  The  free  fat  (ether  extract) 
is  estimated  by  extracting  15  to  18  grams  of  material  with  ether  in  a 
Soxhlet  apparatus,  and  weighing  the  residue;  bleached  fabrics  giving  more 
than  0.4  percent  of  ether  extract  should  be  rejected;  (2)  the  lime  soaps 
(combined  fatty  acids)  are  determined  from  the  sample  just  extracted 
with  ether  by  steeping  for  thirty  minutes  in  a  5  percent  solution  of  hydro- 
chloric acid,  washing,  drying,  and  again  extracting  with  ether  in  a  Soxhlet. 
The  fatty  acids  thus  extracted  are  dried,  dissolved  in  warm  alcohol,  and 
titrated  with  N/20  caustic  soda  solution,  using  phenolphthalein  as  an 
indicator;  well  bleached  cloth  should  not  contain  more  than  0.08  percent 
of  fatty  acids;  (3)  the  ash  is  determined  in  the  usual  manner,  and  well- 
bleached  goods  should  not  contain  more  than  0.05  percent  of  ash.  In 
most  cases  the  amount  of  ash  corresponds  to  the  amount  of  lime  soap 
present.  In  these  tests,  of  course,  it  is  to  be  understood  that  the  sample 
has  not  been  treated  with  any  loading  or  sizing  or  softening  materials. 
The  following  examples  show  the  results  of  such  tests: 


Free  Fat, 
Percent. 


Fatty  Acids, 
Percent. 


Ash, 
Percent. 


Gray  cloth 

After  boiling  with  caustic  soda  and  soda  ash 
Bleached 


1.0448 
0.1761 
0.0210 


0.1359 
0.4923 
0 . 0433 


1.6294 
0,2230 
0  0571 


1  Chetn.  Zeit.,  1902. 


986  TESTING  OF  TEXTILE  FABRICS 

Knecht  ^  has  made  a  study  of  the  action  of  prolonged  heat  on  bleached 
cotton.  The  bleached  cotton  mateiial  was  heated  in  a  water-jacketed  air 
bath  at  80°  to  100°  C.  for  periods  up  to  530  hours.  The  air-dried  material 
was  exposed  in  test-tubes  sealed  with  a  blow-pipe,  or  on  open  watch-glass 
faces.  It  was  found  that  bleached  cotton  yarn  and  cloth  exposed  on 
watch  glasses  remained  unchanged  the  first  few  days,  but  soon  after 
changed  slowly  to  a  grayish-brown  color.  After  336  hours  the  strength 
had  decreased  33  percent,  and  tests  also  showed  the  formation  of  some 
oxycellulose.  Cotton  yarn  exposed  in  tubes  changed  more  rapidly  after 
336  hours.  When  the  tubes  were  broken  under  mercury  they  showed  a 
slight  vacumn  equal  to  about  one-fifth  the  height  of  the  tube,  indicating 
that  oxygen  had  been  absorbed,  and  the  strength  of  the  yarn  had  decreased 
about  50  percent. 

9.  Testing  Waterproof  Fabrics. — In  testing  fabrics  for  waterproof 
qualities  the  common  method  is  to  pour  a  quantity  of  water  on  to  a  pouch 
in  the  cloth.-  The  cloth  should  be  able  to  stand  rubbing  underneath  and 
should  show  no  trace  of  wetness  when  the  water  is  moved  about  over  the 
surface  of  the  cloth.  This  test  is  valueless  when  it  is  desired  to  make  a 
comparison  between  different  processes  or  when  new  processes  are  being 
tried  on  an  experimental  scale,  say,  with  pieces  of  cloth  6  by  6  ins.  A 
common  method  is  to  make  a  pouch  with  a  piece  of  cloth  by  stretching 
it  on  a  suitable  frame. 

The  under  side  of  the  cloth  should  show  no  appearance  of  dampness 
after  two  or  three  days.  Another  good  method  is  to  take  about  6  by  6  ins. 
and  fold  it  twice  like  a  filter  and  place  in  a  suitable  glass  funnel.  A 
definite  volume  of  water  is  measured  into  it,  and  at  the  end  of  twenty -four 
hours  nothing  more  than  a  few  equally  distributed  drops  of  water  should 
be  perceptible  on  the  under  side.  A  good  cloth  will  not  show  any  drops 
on  the  under  side  for  days. 

In  Germany  the  following  test  is  prescribed  for  sail-cloth:  A  sample 
of  the  cloth  10  ins.  square  is  folded  like  a  filter-paper  and  placed  in  a 
suitable  glass  funnel  where  300  cc.  of  water  are  poured  upon  it  and  it  is 

'  Jour.  Roc.  Dyers  &  Col.,  vol.  3G,  p.  195. 

^  Points  to  be  Considered  in  the  Preliminary  Examination  of  the  Material. — One  of 
the  simplest  and  at  the  same  time  most  useful  tests  is  to  hold  a  generous  sample  of 
the  material  between  the  inspector's  eye  and  a  brightly  lighted  window.  A  sur- 
prisingly great  number  of  samples  from  supposedly  high-grade  material  will  show 
numbers  of  pinholes,  uncoated  spots,  reed  marks,  etc.  In  no  case  has  it  been  found 
as  the  result  of  tests  that  material  which  showed  pinholes  resisted  the  passage  of 
water  satisfactorily.  It  has  been  stated  that  the  treatment  would  so  increase  the 
tendency  of  the  cloth  to  resist  wetting  that  water  would  not  go  through  small  holes. 
This  theory  does  not  serve  to  protect  holes  which  may  be  seen  through  in  this  way. 
The  finished  cloth  should  not  have  an  objectionable  odor,  or  be  greasy,  or  very  stiff. 
The  coating  should  not  rub  off  or  dust  off,  nor  crack  on  sharp  creasing,  nor  should 
it  make  the  cloth  tacky.     The  color  should  be  even  and  attractive  for  the  purpose. 


TESTING   WATERPROOF   FABRICS  987 

left  for  twenty-four  hours.  At  the  end  of  this  time  only  a  few  equally 
distributed  drops  of  water  should  be  discovered  on  the  under  surface 
of  the  cloth,  and  the  fabric  should  not  be  wet  through. 

The  U.  S.  War  Department  gives  the  following  specifications  for  the 
quantitative  testing  of  rainproof  and  waterproof  cloth: 

(1)  The  Drop  Test. — This  is  a  test  which  furnishes  a  numerical  value  representing 
degree  of  waterproofing  under  conditions  approximating  more  or  less  to  rain.  The 
sheet  of  cloth  is  laid  upon  blotting  paper  on  a  glass  plate,  supported  at  an  angle  of  45°. 
Beneath  the  plate  is  a  horizontal  mirror.  Water  is  dropped  5  ft.  from  a  burette  on 
to  the  cloth  at  the  rate  of  20  drops  a  minute,  and  this  is  continued  until  the  water 
passes  through  the  cloth  and  stains  the  blotting  paper,  which  can  be  viewed  in  the 
mirror,  and  the  number  of  drops  required  thus  determined.  Considerable  variations 
occur  between  the  minimum  and  maximum  drop  numbers,  but  the  average  of  twenty 
trials  is  regarded  as  characteristic.  An  average  of  6.4  drops  is  obtained  in  a  cloth 
sufficiently  impermeable  for  most  purposes,  while  15  drops  represent  a  very  good 
class  of  cloth.  To  pass  the  War  Office  test,  however,  60  drops  are  required.  The 
cloth  should  be  tested  again  after  rinsing  in  cold  water  and  drying,  or,  for  a  more 
severe  test,  soaking  in  water  twenty-four  hours  and  drying.  The  cloth  should  also 
be  ironed  while  covered  with  a  damp  cloth,  and  again  tested. ^ 

(2)  The  Dash  Test. — Water  is  poured  on  to  the  cloth,  which  is  held  horizontal 
meanwhile.     A  test  of  no  particular  value. 

(3)  The  Trough  Test. — The  cloth  is  suspended  by  its  four  corners  and  500  cc.  of 
water  poured  in.  It  is  of  httle  use,  except  as  a  test  for  holes,  owing  to  the  length  of 
time  required. 

(4)  The  Filter  Test. — Widely  used  in  the  trade,  but  not  nearly  so  good  as  the  drop 
test.  It  is,  however,  useful  for  detecting  pinholes.  A  square  piece  of  cloth  of  10  ins. 
side,  is  folded  like  a  filter  paper,  and  placed  in  a  glass  funnel  of  60°,  with  300  cc.  of 
water  inside.  After  twenty-four  hours  the  stuff  should  not  be  wet  through.  A  good 
modification  is  to  fasten  a  piece  of  cloth  over  a  thistle  funnel,  invert  it,  fill  with  cold 
water,  and  support  for  ten  hours  over  a  graduated  cylinder.  Cloth  which  allows  no 
water  to  pass  in  ten  hours  is  considered  excellent. ^ 

^  Many  firms  make  use  of  the  dropping  tap  for  testing  their  waterproof  goods. 
A  bottle  or  cistern  is  fitted  with  a  dropping  tap  to  allow  drops  of  water  to  fall  at  regular 
intervals.  A  wooden  frame  is  inclined  at  an  angle  of  45°.  One  edge  of  the  cloth  to 
be  tested  is  fastened  to  the  uppermost  edge  of  the  frame,  and  the  cloth  allowed  to  fall 
over,  the  bottom  edge  being  kept  taut  by  means  of  a  bar  to  which  the  bottom  edge 
of  the  cloth  is  fastened.  The  drops  of  water  are  allowed  to  drop  on  the  center  of  the 
cloth.  At  first  they  run  down  the  incHne,  but  after  some  time  elapses,  say  from  one 
to  five  hours,  according  to  the  quality  of  the  waterproof,  the  drops  begin  to  go  through 
the  cloth.  The  time  elapsing  before  this  occurs  is  taken  as  the  value  of  the  proofing. 
According  to  the  height  the  water  has  to  fall,  minute  drops  will  spray  through  the 
interstices,  but  the  water  does  not  collect  to  form  a  drop  for  a  considerable  time. 

The  dropping  test  may  also  be  carried  out  as  follows :  The  cloth  is  extended  beneath 
the  dropping  tap  and  a  piece  of  blotting  paper  placed  underneath  the  portion  of  cloth 
where  the  drops  will  fall.  Sixty  drops  are  allowed  to  descend  from  an  elevation  of 
6  ft.  and  if  the  blotting  paper  shows  no  wetness  after  the  test  the  cloth  is  considered 
satisfactorily  proofed. 

2  The  thistle  funnel  forms  a  convenient  and  excellent  means  for  the  comparative 
testing  of  waterproof  fabrics.     A  portion  of  the  cloth  is  tied  firmly  on  to  the  thistle  end. 


988  TESTING  OF  TEXTILE  FABRICS 

Gawalowski  describes  an  apparatus  for  determining  the  waterproof 
qualities  of  a  fabric  as  follows :  The  sample  of  the  cloth  is  attached  to  the 
open  end  of  a  graduated  tube  (a  burette  will  serve  the  purpose,  using  the 
large  opening  for  the  cloth),  which  is  then  filled  with  a  column  of  water 
12  ins.  in  height.  At  the  end  of  twenty-four  hoiu-s  an  observation  is  made 
as  to  how  much  water  has  passed  through  the  cloth. 

Another  method  of  testing  which  is  of  value  in  differentiating  between 
good  and  useless  waterproof  canvas  is  to  take  a  piece  of  the  fabric  and 
fold  it  into  a  pocket,  placing  a  variety  of  heavy  articles  in  the  pocket, 
and  irmnerse  as  far  as  possible  in  water.  A  good  fabric  should  not  wet 
through  in  twenty-four  hours. 

Tulle  and  similar  fabrics  can  be  so  prepared  that  they  will  not  be  spoiled  by  rain, 
and  can  be  cleaned  with  a  wet  sponge.  This  is  done  by  impregnating  the  material 
with  an  ordinary  solution  of  collodion,  to  which  enough  amyl  acetate  has  been  added 
to  make  the  drying  slow.  The  tulle,  after  treatment,  has  a  soft  handle  and  ample 
luster.  The  coating  does  not  peel  off.  Gum-lac  is  added  with  advantage.  One 
recipe  in  the  specification  ^  is  as  follows:  6  kilos,  of  gum-lac  is  dissolved  in  4  liters 
of  spirit  and  16  liters  of  amyl  acetate.  After  complete  solution  the  liquid  is  mixed 
with  13  liters  of  collodion. 

W.  Borks  ^  uses  a  mixture  of  ceresin,  Venice  turpentine,  paraffin,  and  crude  rubber 
for  waterproofing,  especially  for  coarsely  woven  fabrics  or  nets.  The  recipe  is  as 
follows:  Melt  together  375  lbs.  of  ceresin,  400  lbs.  of  Venice  turpentine,  and  150  lbs. 
of  paraffin  wax,  and  then  stir  in  a  thick  solution  of  3  lbs.  of  unvulcanised  India  rubber. 
The  rubber  does  not  contribute  much  to  the  waterproofing,  its  function  being  rather 
to  bind  the  other  ingredients  on  to  the  fiber.  It  is  claimed  that  this  composition  not 
only  perfectly  waterproofs  the  fabric,  but  improves  its  resistance  to  wear. 

and  the  funnel  fixed  in  an  inverted  position  in  a  clamp.  By  means  of  a  wash  bottle 
the  globe  part  is  filled  with  water.  This  will  represent  about  1  in.  pressure  and  any 
cloth  if  at  all  waterproof  will  stand  this.  With  a  pipette  the  pressure  of  water  is 
gradually  increased,  the  water  level  mounting  up  the  stem  of  the  funnel.  One  should 
be  able  to  increase  the  pressure  until  it  is  sufficient  to  force  drops  between  the  inter- 
stices. The  level  in  the  stem  of  the  funnel  now  falls  some  distance  when  it  remains 
constant  and  will  stay  so  for  days.  The  height  of  the  water  is  measured  and  may 
be  taken  as  indicating  the  degree  of  "proofing."  Anything  above  2  ins.  of  water  is 
quite  good.  The  underside  should  not  become  wet  and  the  water  when  forced  through 
by  the  pressure  should  be  in  evenly  dispersed  drops.  It  is  also  possible  to  get  figures 
by  filling  up  to  a  certain  height  for  each  test,  and  measuring  the  time  elapsing  before 
the  first  diop  appears  on  the  underside  or  the  amount  of  water  passing  through  in  a 
certain  time,  say  ten  hours.  More  elaborate  modern  testing  apparatus  is  very  similar 
to  the  foregoing  in  principle.  A  column  of  water  is  allowed  to  act  on  the  test  sample 
and  the  water  passing  through  in  a  given  time  is  measured.  In  one  such  apparatus 
a  graduated  burette  has  its  lower  extremity  closed  with  an  attachment  resembling  a 
polarising  tube,  but  instead  of  the  glass  disk  found  in  such  tubes  the  sample  of  cloth 
is  cut  to  correct  size  and  fitted  in.  A  slanting  outlet  is  cut  through  the  metal 
attachment  and  a  small  measuring  flask  placed  underneath.  The  burette  is  filled 
up  to  the  zero  mark,  and  the  amount  of  water  falling  through  in  twenty-four  hours 
collected. 

1  Ger.  Pat.  258,471.  2  q^  Pat.  275,659. 


TESTING  WATERPROOF  FABRICS 


989 


Glass  Tube 


Copper  Ring: 


Fig.  410. — Wosnessensky's  Apparatus  for  Testing  Water- 
proof Quality  of  Fabrics. 


Wosnessensky  ^  describes  an  apparatus  recommended  for  the  testing 
of  waterproof  cloth.  It  consists  of  a  cylindrical  copper  box  (see  Fig.  410) 
to  which  are  attached  a  glass  measuring  tube  and  a  rubber  bulb.  On  the 
top  of  the  box  are  fixed,  by  means  of  two  screws,  two  rings,  one  of  copper 
and  the  other  of  rubber.  At  the  beginning  of  the  test  the  box  is  filled 
with  water,  and  on  the 
top  is  fixed  a  piece  of  the 
cloth  to  be  tested.  By 
pressing  the  bulb  the 
height  of  the  water  in  the 
glass  tube  rises  and  meas- 
ures the  pressure  within 
the  box.  When  this  be- 
comes sufficiently  small, 
drops  of  water  will  be- 
observed  on  the  surface 
of  the  cloth.  The  height 
of  the  water  column  meas- 
ures the  degree  of  imper- 
meability of  the  sample. 

Heermann  described  several  methods  of  testing  waterproof  fabrics  as 
follows: 

(1)  Bag  Test. — A  square  of  the  fabric,  50  by  50  cm.  oi  100  by  100  cm.  is  tied  with 
strings  by  the  four  corners  to  a  frame  in  such  a  way  that  a  bag  is  formed.  The  bag 
is  filled  to  a  given  height  with  water  at  the  temperature  of  the  room.  The  height 
of  the  column  of  water  used  varies,  depending  on  the  uses  to  which  the  fabric  is  to 
be  put.  No  dropping  or  trickUng  through  of  water  should  take  place  in  twenty-four 
hours,  but  sweating  through  or  transudation  is  permitted.  Uniform  cloth,  tent  cloth, 
fabric  for  knapsacks  and  bread  bags  were  tested  by  this  method,  using  pieces  50  cm. 
square,  filled  with  water  to  a  depth  of  75  mm.  After  twenty-four  hours  the  water 
may  sweat  through  but  should  not  drip  through.  The  specifications  for  wagon  covers 
for  the  Prussian  State  Railway  prescribed  that  a  piece  100  cm.  square  should  be  used 
and  that  the  depth  of  water  should  be  10  cm.  After  twenty-four  hours  there  should 
be  no  dripping.  Heermann  considers  one  test  as  usually  sufficient,  but  in  certain 
circumstances  the  same  piece  is  dried  and  tested  for  a  second  or  third  time,  in  order 
to  determine  how  the  fabric  stands  wear. 

(2)  Spray  Test. — A  piece  of  cloth  50  by  50  cm.  is  weighed  after  having  been  exposed 
to  65  percent  relative  moisture  for  several  hours.  It  is  then  spread  out  smoothly 
on  a  frame  and  set  up  outdoors  in  a  slanting  position.  A  sprinkling  apparatus  con- 
nected with  the  water  supply  is  set  up  at  a  distance  of  6  to  10  meters  from  the  cloth, 
and  the  nozzle  is  arranged  so  that  a  fine  spray  strikes  equally  all  over  and  falls  from 
a  height  of  2  to  3  meters.  The  under  surface  is  examined  from  time  to  time  for 
penetration  of  water.  If  the  water  has  not  penetrated  the  spraying  is  continued. 
Whether,  and  at  what  time,  water  appears  on  the  under  side  during  the  spraying  is 


1  Jour.  Soc.  Dyers  &  Col,  1915,  p.  50. 


990  TESTING  OF  TEXTILE   FABRICS 

also  observed.  At  the  end  of  an  hour  the  spraying  is  stopped,  the  materials  is  hung 
up  to  dry  for  five  minutes  and  weighed.  It  is  claimed  that  the  smaller  the  amount 
of  water  absorbed  the  more  eflScient  is  the  waterproofing  preparation.  Duplicate  or 
triplicate  tests  are  made. 

Villavecchia  describes  a  spray  test  in  which  the  fabric  is  inclined  at 
an  angle  of  25  degrees  and  water  allowed  to  drip  upon  it  for  three  hours 
from  a  height  of  two  meters  at  a  rate  of  31  per  minute  on  the  central 
part  of  the  fabric  so  as  to  cover  an  area  of  3  cm.  in  circumference.  At 
the  end  of  the  experiment  no  water,  or  at  most  a  minimum  quantity, 
should  have  penetrated  the  fabric. 

Veitch  and  Jarrel  ^  after  an  exhaustive  comparison  of  the  different 
methods  for  testing  waterproofed  fabrics  devised  the  following  methods: 

Modified  Funnel  Test. — Cut  a  piece  of  the  fabric  1  ft.  square,  weigh,  crumple 
thoroughly  in  the  hand  and  place  in  an  800-cc.  beaker  and  soak  in  distilled  water 
at  from  70°  to  80°  F.  for  twenty-four  hours,  removing,  straightening  out  and  recrumpling 
four  or  five  times  during  this  period.  Remove  from  the  water,  straighten  out  and  dry 
in  oven  at  45°  C.  for  twenty-four  hours,  and  hang  in  laboratory  overnight.  Crumple, 
resoak  in  distilled  water,  and  dry  at  45°  C.  for  twenty-four  hours,  and  hang  in  labo- 
ratory overnight  as  before.  Again  crumple,  smooth  out  and  place  on  a  piece  of 
absorbent  paper  (paper  towelling)  of  the  same  size  and  fold  the  two  together  into 
the  form  of  a  filter,  insert  in  a  6-in.  glass  funnel  having  an  angle  of  60°,  and  place  the 
funnel  in  a  support  over  a  500-cc.  graduated  glass  cyUnder  and  fill  the  funnel  to  a 
depth  of  exactly  4  ins.  with  distilled  water  of  70°-80°  F.  This  depth  equals  500  cc. 
of  water.  Maintain  a  constant  water  level  above  the  funnel  by  inverting  an  Erlen- 
meyer  flask  filled  with  water  and  closed  with  a  rubber  stopper  through  which  passes 
a  glass  tube  ground  at  the  end  to  an  angle  of  45°. 

Make  the  following  observations: 

1.  The  time  elapsed  before  the  paper  begins  to  wet. 

2.  The  time  elapsed  until  the  paper  is  entirely  wet. 

3.  The  time  elapsed  before  the  first  drop  passes  into  the  cylinder. 

4.  The  quantity  of  water  in  the  cylinder  in  one,  three,  six  and  twenty-four  hours. 

5.  The  time  and  extent  to  which  the  fabric  becomes  wet  above  the  water  level. 
At  the  expiration  of  twenty-four  hours,  if  there  has  been  no  dripping,  the  funnel 

filled  with  water  is  lifted  2  ins.  and  allowed  to  drop  into  its  support;  this  is  repeated 
four  times  and  the  amount  of  water  that  drips  through  in  three  hours,  if  any,  is 
recorded. 

Remove  the  funnel  from  its  support  and  carefully  pour  and  drain  off  the  water, 
and  then  remove  the  fabric  and  paper  from  the  funnel,  smooth  out  and  observe : 

1.  Whether  the  paper  is  dry,  damp  or  wet. 

2.  Whether  the  fabric  on  the  outside  is  dry,  damp  or  wet,  or  whether  the  water 
has  only  sweated  through. ^ 

^  U.  S.  Bureau  of  Chemistry. 

^  The  water-resistance  of  fabrics  as  determined  by  this  method  is  rated  in  accord- 
ance with  the  following  scale : 

Very  High  10. — The  fabric  does  not  become  wet  above  the  water  level  within 
twenty-four   hours.     No   water   drips   through.     No   sweating   through   is   apparent 


TESTING  WATERPROOF  FABRICS  991 

Modified  Spray  Method. — Dry  the  piece  of  fabric  used  in  conducting  the  funnel 
test  at  45°  C.  for  twenty-four  hours,  hang  in  laboratory  overnight  and  {'lamp  loosely 
in  a  frame.  Set  the  frame  in  a  holder  attached  to  a  trough  at  an  angle  of  45°.  The 
trough  used  held  six  frames.  Allow  clear  tap  water  at  room  temperature  to  fall  from 
a  height  of  6  ft.  upon  the  central  portion  of  the  fabric,  covering  an  area  of  about  8  ins. 
in  circumference,  for  twenty-four  hours,  from  a  2f-in.  brass  spray  nozzle  having  25 
holes,  each  1.9  (0.75  in.)  mm.  in  diameter,  at  a  rate  of  1000  cc.  per  minute. 

Inspect  the  condition  of  the  under-side  of  the  fabric  at  the  end  of  five  minutes, 
one-half  hour,  one  hour,  three  hours,  seven  hours,  and  twenty-four  hours.  Note  at 
each  inspection  whether  the  under  surface  is  dry,  damp  or  wet  with  no  dripping; 
damp  or  wet  with  dripping. i 

except  to  a  very  limited  extent  at  the  folds.  Filter  paper  under  the  fabric  remains 
dry,  except  for  slight  wetting  where  the  fabric  is  folded. 

High  9. — The  fabric  does  not  wet  above  the  water  level  within  twenty-four  hours. 
Sweating  through  is  sufficiently  rapid  to  cover  generally,  and  especially  in  the  fold, 
the  outside  of  the  fabric  with  droplets.     Filter  paper  under  the  fabric  becomes  wet. 

High  Medium  7  and  8. — The  water  dripping  through:  In  six  hours  is  from  1  cc. 
to  5  cc.  In  twenty-four  hours  is  from  1  cc.  to  25  cc.  In  three  hours  after  raising 
and  allowing  the  funnel  to  drop  into  support  five  times. 

Medium  5  and  6. — The  water  dripping  through:  In  six  hours  is  from  5  to  25  cc. 
In  twenty-four  hours  is  from  25  to  50  cc. 

Medium  Loiv  3  and  4- — Tbe  water  dripping  through:  In  six  hours  is  from  25  to  75  cc. 
In  twenty-four  hours  is  from  50  to  150  cc. 

Low  1  and  2. — The  fabric  wets  above  the  water  level  readily.  The  water  dripping 
through:  In  six  hours  is  from  75  to  200  cc.     In  twenty-four  hours  is  from  150  to  300  cc. 

Negligible  0. — The  water  dripping  through  in  twenty-four  hours  exceeds  300  cc. 

^  The  water-resistance  of  fabrics  as  determined  by  the  modified  spray  test  is  rated 
on  a  scale  of  ten  as  follows : 

10.  Under  surface  of  fabric  remains  dry  for  twenty-four  hours. 

9.  Under  surface  remains  dry  for  seven  hours  but  is  damp  or  wet  in  twenty-four 
hours.     No  dripping. 

8.  Under  surface  remains  dry  for  seven  hours  but  is  damp  or  wet  in  twenty-four 
hours.     Dripping. 

Under  surface  remains  dry  for  three  hours  hours  but  is  damp  or  wet  in  seven  hours. 
No  dripping. 

7.  Under  surface  remains  dry  for  three  hours  but  is  damp  or  wet  in  seven  hours. 
Dripping. 

6.  Under  surface  remains  dry  for  one  hour  but  is  damp  or  wet  in  three  hours.  No 
dripping. 

5.  Under  surface  remains  dry  for  one  hour  but  is  damp  or  wet  in  three  hours. 
Dripping. 

4.  Under  surface  remains  drj^  for  one-half  hour  but  is  damp  or  wet  in  one  hour. 
No  dripping. 

3.  Under  surface  remains  dry  for  one-half  hour  but  is  damp  or  wet  in  one  hour. 
Dripping. 

2.  Under  surface  remains  dry  for  five  minutes  but  is  damp  or  wet  in  one-half  hour. 
No  dripping. 

1.  Under  surface  remains  dry  for  five  minutes  but  is  damp  or  wet  in  one-half  hour. 
Dripping. 

0.  Under  surface  damp  to  dripping  in  five  minutes. 


992 


TESTING  OF  TEXTILE   FABRICS 


The  spray  test  appears  to  check  better  with  the  results  obtained  by  exposure  to 
an  actual  rain  than  the  funnel  test. 

The  Macintosh  apparatus  for  testing  the  waterproof  quality  of  fabrics 
is  shown  in  Fig.  411.  The  cloth  to  be  tested  is  cut  in  the  form  of  a  square 
and  inserted  in  the  apparatus  so  that  it  is  pressed  firmly  against  the  open 
under  side  of  the  small  pressure  cylinder.  A  couple  of  inches  of  water 
are  then  allowed  to  flow  into  the  latter  and  then  pressure  is  gradually 

applied,  the  degree  of  which  is  shown  by 
the  reading  on  the  manometer.  A  mirror 
placed  beneath  is  used  to  observe  the 
behavior  of  the  fabric.  The  maximum 
water-resistance  of  the  fabric  is  determined 
by  reading  the  the  pressure  when  the  first 
drop  of  water  has  penetrated  the  cloth. 
For  comparison  it  is  said  that  the  heaviest 
rain  does  not  exert  a  pressure  of  more 
than  12  ins.  of  water.^ 

10.  Testing  the  Liability  of  Waterproofed 
Fabrics  to  Spontaneous  Combustion. — In 
the  waterproofing  of  fabrics  the  materials 
employed  to  render  the  goods  waterproof 
may  often  introduce  the  risk  of  their  be- 
coming spontaneously  inflammable.  Oils 
that  readily  absorb  oxygen  if  used  in  large 
amount  upon  a  fabric  may  readily  cause  the 
development  of  sufficient  heat  to  set  fire 
to  the  goods.  While  mineral  oils  are  free 
from  this  objection,  they  afford  a  ready 
fuel,  and  their  vapors  aid  in  the  actual 
starting  of  the  flame.  In  waterproofing  compositions  the  chief  danger 
arises  from  the  use  of  linseed  oil  which  while  alone  is  readily  sensitive  to 
oxidation  and  consequent  heating,  has  this  liability  increased  by  the 
use  of  materials  on  the  fabric  which  promote  its  absorption  of  oxygen. 
Thus  by  the  presence  of  true  oxidants,  catalytic  agents  of  oxidation  and 
the  porous  character  of  the  oiled  material,  grave  risk  is  at  times  encoun- 
tered of  the  complete  destruction  of  the  goods.  This  is  more  likely  to 
happen  during  the  waterproofing  of  the  material  or  soon  after. 

While  in  the  operations  of  waterproofing  with  oils  known  to  be  of  an 
oxidising  nature,  certain  rough  tests  are  made  from  time  to  time  to  control 
the  product  and  to  guard  against  the  risk  of  inflammability,  there  is 
grave  lack  of  a  standard  method  of  testing  these  fabrics,  or  such  tests 
as  are  employed  fail  to  indicate  with  definiteness  whether  the  fabric  will 
1  Col<»-  Trade  Journal,  1922,  p.  5. 


Fig.   411. — Macintosh   Apparatus 
for  Testing  Waterproof  Fabrics. 


TESTING   WATERPROOFED  FABRICS  993 

be  safe.  For  this  purpose  no  instrument  is  better  than  the  Mackey 
apparatus  for  testing  the  liability  of  oils  to  spontaneous  combustion.^ 
This  has  been  found  by  frequent  tests  superior  to  other  types  of  apparatus 
having  the  same  end  in  view. 

The  apparatus  consists  of  a  cylindrical  water-jacketed  metal  oven  of 
the  following  dimensions:  Outside  8  ins.  high  and  6  ins.  in  diameter; 
inside  7  ins.  high  and  4  ins.  in  diameter.  The  vessel  is  sealed  with  a  lid 
lined  with  non-conducting  material  and  having  three  holes,  one  at  the 
center  for  a  thermometer,  and  two  diametrically  opposite  near  the  rim 
which  receive  copper  tubes  of  |-in.  diameter  so  arranged  that  when  the 
lid  is  in  place,  one  tube  enters  the  oven  to  a  depth  of  6  ins.,  while  the 
other  rises  to  an  equal  height  above  the  lid.  These  tubes  assure  a  constant 
draft  of  air  through  the  instrument.  In  common  vertical  axis  with  the 
central  hole  there  is  supported  within  the  oven  a  cylinder  of  wire  gauze 
6  ins.  long  and  1^  ins.  in  diameter.  The  fabric  which  is  suspected  of 
liability  to  spontaneous  inflammability  is  placed  in  a  finely  chipped  con- 
dition within  the  cylinder  occupying  the  upper  4^  ins.,  and  the  thermometer 
is  so  arranged  that  the  bulb  is  in  the  center  of  this  mass.  The  water  is 
brought  to  the  boiling-point  and  the  cylinder  and  thermometer  are  intro- 
duced, the  latter  protruding  through  a  cork  placed  in  the  central  hole  in 
the  lid.  The  boiling  temperature  is  maintained  and  the  thermometer  is 
read  at  the  end  of  the  hour  and  every  fifteen  minutes  thereafter;  noting, 
however,  if  between  these  times  a  maximum  of  rise  is  reached.  The 
cylinder  may  be  dispensed  with  if  a  piece  of  the  fabric  4|  by  36  ins.  be 
wrapped  directly  about  the  thermometer.  If  the  fabric  tested  attains  a 
temperature  of  100°  C.  within  an  hour,  or  if  it  reaches  a  temperature 
of  120°  C.  within  an  hour  and  a  half,  it  must  be  considered  as  dangerous. 

11.  Testing  Waterproofed  Fabrics  for  the  Effect  of  Extremes  of  Climate. 
— The  testing  for  the  effect  of  extremes  of  climate  is  of  especial  importance. 
It  does  not  seem  unreasonable  to  expect  the  material  to  withstand  tem- 
peratures of  120°  F.  and  0°  F.  as  maximum  and  minimum.  The  effect 
of  heating  can  be  readily  determined  by  the  use  of  an  oven.  The  effect  of 
cold  is  harder  to  obtain.  Clark  makes  a  freezing  mixture  of  salt  and 
shaved  ice,  and  obtains  an  approximation  of  0°  F.  in  this  way.  The 
paraffined  cloths  will  frequently  be  found  to  be  very  brittle  at  the  lower 
temperatures,  while  some  of  the  substances  used  will  be  very  sticky 
and  even  volatile  at  the  higher  temperature.  The  heating  should  be 
continued  for  at  least  eight  hours,  and  test  for  waterproof  value  made  on 
the  sample  after  heating.  The  aging  effect  of  sunlight  must  also  be 
considered,  and  where  practicable  it  is  advisable  to  expose  the  samples 
to  the  light  from  a  dye-fading  mercury  or  arc  lamp  for  forty-eight  to 

1  Jour.  Soc.  Chem.  Ind.,  1896,  p.  90,  aad  1907,  p.  185. 


994  TESTING  OF  TEXTILE  FABRICS 

seventy-two  hours.     Some  fabrics  will  lose  completely  their  waterproof 
value  as  a  result  of  this  exposure. 

12.  Testing  the  Durability  of  Fabrics. — It  has  generally  been  the  prac- 
tice to  test  fabrics  by  obtaining  the  tensile  strength  of  warp  and  filling, 
but  this  method  does  not  accurately  measure  the  actual  durability  or 
wearing  qualities  of  the  cloth.  Kertesz  has  devised  the  following  method : 
Cuttings  of  cloth  23  cm.  long  (warp  direction)  and  32  cm.  broad  (filling 
direction)  are  treated  for  three-quarters  of  an  hour  at  94°  C.  with  10 
percent  of  hydrochloric  in  a  liquor  forty  times  the  weight  of  the  cloth. 
The  cutting  must  not  be  folded  during  the  treatment.  It  is  rinsed  with 
distilled  water  till  almost  neutral,  squeezed  and  extracted  in  a  Soxhlet 
apparatus  with  400  cc.  of  alcohol  for  an  hour  and  a  half.  The  samples 
are  then  squeezed,  rinsed,  and  squeezed  again,  followed  by  drying  for  two 
hours  at  70°  C.  After  drying  they  are  kept  for  at  least  half  an  hour  in  an 
oven  at  25°  C.  before  scraping  tests  are  made.  The  cuttings  are  divided 
into  six  strips,  each  5  cm.  broad,  and  these  strips  are  stretched  singly  in 
the  jaws  of  the  scraping  machine,  three  bemg  scraped  on  the  face  and 
three  on  the  back.  The  testing  is  done  comparatively  with  some  standard 
cloth,  the  relative  figures  being  given  b}'  the  number  of  revolutions  required 
before  the  cloth  tears.  Scraping  rollers  provided  with  engraved  flutes 
proved  best  suited  for  the  pin-pose. 

13.  Testing  Permeability  of  Balloon  Fabrics. — A  method  for  conduct- 
ing this  test  is  given  by  Edwards  and  Pickering^  as  follows:  The  fabric 
which  is  to  be  tested  is  firml}^  held  between  the  two  halves  of  a  circular 
metal  cell,  which  is  divided  thereby  into  two  chambers.  A  current  of 
pure  dry  hydrogen  gas  is  passed  through  one  chamber  so  that  one  surface 
of  the  fabric  is  maintained  in  an  atmosphere  of  hydrogen  under  a  pressure 
of  30  mm.  of  water  above  the  pressure  on  the  opposite  side,  and  a  current 
of  dry  carbon  dioxide  gas  is  passed  through  the  other  chamber.  The 
cell  is  suspended  in  a  constant-temperature  bath  maintained  at  25°  C 
The  hydrogen  which  penetrates  the  fabric  is  swept  by  the  carbon  dioxide 
into  a  bulb  containing  caustic  soda  solution.  The  residual  gas  in  this  bulb 
will  consist  of  hydrogen  together  with  traces  of  air  originally  present  in 
the  carbon  dioxide,  and  is  passed  into  an  explosion  burette,  where  the 
hydrogen  is  determined. 

14.  Testing  the  Heat-retaining  Value  of  Fabrics. — A  number  of 
devices  have  been  suggested  for  testing  the  permeability  of  fabrics  to  heat 
with  the  idea  of  determining  their  heat-retaining  values  for  clothing. 
The  German  Testing  Bureau  recommends  the  following:  A  copper  flask 
having  a  flat  bottom  of  5.5.  cm.  diameter  is  surrounded  by  cotton  and  an 
insulating  casing,  and  rests  on  a  piece  of  felt  on  a  wooden  block;  200  cc. 
of  hot  water  are  placed  in  the  flask  and  heated  by  steam  until  a  temperature 

^Jour.  Ind.  Eng.  Chem.,  1919,  p.  966. 


TESTING   HEAT-RETAINING   VALUE   OF  FABRICS  995 

of  100°  C.  is  reached  when  the  junction  of  a  thermo-electric  couple  is 
placed  between  the  flask  and  the  piece  of  felt  and  the  temperature  noted 
at  two-minute  intervals  for  ninety  minutes.  The  test  is  repeated  with  a 
sample  of  the  material  under  examination  between  the  bottom  of  the  flask 
and  the  felt.  The  tests  did  not  indicate  the  existence  of  any  relation 
between  the  "heat-protection  value"  of  the  fabric  and  its  nature,  thickness, 
density,  and  other  qualities,  and  the  test  is  therefore  only  relative. 


CHAPTER  XXVIII 
ANALYSIS  OF  FIBERS  AND  YARNS  IN  FABRICS 

1.  Microscopic  Analysis  of  Fabrics. — Hohnel  describes  the  following 
method  employed  for  a  microscopic  examination  of  textile  fabrics,  where 
the  object  is  to  determine  not  only  qualitatively  the  character  of  fibers 
composing  them,  but  also  their  quantitative  amounts.  With  regard  to  the 
preliminary  qualitative  examination,  there  are  generally  only  a  few  fibers 
to  be  taken  into  consideration,  as  there  seldom  occur  in  the  same  fabric 
more  than  one  to  four  different  kinds  of  fibers.  As  a  rule,  the  only  fibers 
which  will  be  found  are  cotton,  linen,  hemp,  jute,  ramie,  sheep's  wool, 
goat-hair,  cow-hair,  angora,  alpaca,  cashmere,  llama,  silk,  and  tussah  silk. 
In  woolen  material  there  are  also  cosmos  and  shoddy  to  be  considered. 

To  undertake  the  examination,  cut  off  a  sample  of  the  material  2  to  3 
sq.  cm.  in  size,  and  separate  this  into  its  warp-  and  filling-threads.  The 
sample  must  be  of  sufficient  size  to  include  all  of  the  different  kinds  of 
yarns  employed  in  the  weave.  Consequently,  in  the  case  of  large  patterns, 
it  has  to  be  rather  large.  The  warp-  and  filling-threads  are  laid  next  to 
each  other,  and  one  of  each  kind  is  selected  to  serve  for  further  examination. 
In  the  simplest  case  there  is  only  one  kind  of  warp-thread  and  one  kind  of 
filling  present,  which  necessitates,  therefore,  the  examination  of  only  two 
different  yarns.  In  complicated  cases  there  may  be  as  many  as  ten,  or 
even  more,  different  yarns  to  analyse.  In  woolen  fabrics  there  will  fre- 
quently be  found  yarns  which  are  composed  of  two  or  three  different 
threads  twisted  together;  these  must  be  untwisted  and  each  separate 
yarn  examined  by  itself. 

In  order  to  attain  satisfactory  results,  the  operator  must  be  sufficiently 
skilled  in  the  microscopy  of  the  fibers  to  be  able  to  recognise  with  certainty, 
under  a  low  magnification,  the  different  fibers  liable  to  be  found.  By  a 
low  magnification  is  meant  one  of  fifty  to  sixty  times.  A  much  higher 
power  cannot  be  used  in  the  examination  of  fabrics,  for  hundreds  or  even 
thousands  of  fibers  have  to  be  taken  into  consideration.  From  ten  to 
twenty  fibers,  or  perhaps  more,  should  be  obtained  in  the  field  at  the 
same  time,  and  it  is  necessary  to  be  able  to  promptly  recognise  the  different 
ones.  With  a  higher  magnification,  it  is  true,  the  single  fibers  can  be 
better  recognised,  but  the  general  view  is  then  lost,  and  there  is  danger  in 
overlooking  whole  bundles  of  fibers.     If  the  observer  finds  a  fiber  which 

996 


MICROSCOPIC   ANALYSIS   OF  FABRICS  997 

cannot  be  recognised  with  sufficient  accuracy  by  means  of  the  low  power, 
it  is  a  simple  matter  to  so  change  the  objective  as  to  increase  the  magnifica- 
tion to  allow  of  the  necessary  observations  to  be  made,  and  then  to 
proceed  again  with  the  examination  under  the  lower  power. 

Dark-colored  material  often  consists  for  the  most  part  of  threads 
which,  on  microscopic  examination,  appear  quite  opaque,  hence  dark  and 
structureless.  Therefore  it  will  frequently  be  necessary  to  remove  the 
dyestuff,  at  least  in  part,  which  is  usually  done  by  boiling  in  acetic  acid, 
hydrochloric  acid,  dilute  caustic  alkali,  potassium  carbonate,  etc.,  until 
sufficiently  light  in  appearance. 

In  the  case  of  very  accurate  examinations,  each  different  kind  of  thread 
must  be  examined  separately,  and  the  number  of  fibers  composing  it, 
together  with  their  kind  and  color,  must  be  noted.  In  order  to  show  the 
detail  and  scope  of  such  an  examination,  the  following  example  is  given: 
On  unravelling  a  sample  four  different  warp-threads  and  one  filling-thread 
were  obtained.  One  of  the  warp-threads  was  composed  of  two  yarns 
twisted  together  one  of  which  was  black  (Kio)  and  the  other  white  (Kih). 
Two  warp-threads  were  dark  blue  ( K2  and  K3)  and  the  fourth  was  a  gray 
mix  ( K4) ;  the  filling-thread  (E)  was  blue.  On  examination  the  following 
results  were  obtained: 

Kia  showed  85  shoddy  fibers  (mostly  black,  some  yellow  and  red  and  even  isolated 
green  fibers  of  wool  and  13  cotton  fibers). 

Kib  showed  31  pure  white  wool  fibers. 

K2  and  K',,  respectively,  showed  46  and  53  pure  blue  wool  fibers. 

Ki  showed  60  shoddy  fibers,  of  which  32  were  mostly  gray  or  black  wool  fibers, 
and  28  were  gray  cotton  fibers. 

E  showed  60  blue  wool  fibers. 

Therefore  in  this  sample,  including  4  warp-  and  4  filling-threads,  there  would  be 
85+31+46+53+60  =  275  single-warp  fibers;  and  60X4  =  240  filling  fibers;  or  515 
single  fibers  altogether.  Of  these  31  were  cotton,  which  were  found  in  the  shoddy, 
the  latter  comprising  145  fibers  in  all.  Hence  in  a  sample  of  this  piece  of  goods  con- 
taining equal  lengths  of  warp  and  weft,  there  are  41  cotton  fibers,  104  shoddy  wool 
fibers,  and  370  pure  wool  fibers,  from  which  the  respective  percentages  would  be: 

Percent. 

Cotton 8.0 

Shoddy  wool 20 . 2 

Pure  wool 71.8 


100.0 


This,  of  course,  only  gives  the  relative  percentages  of  the  number  of 
fibers;  if  it  is  desired  to  reach  an  approximate  idea  of  the  proportions 
by  weight,  then  micrometric  measurements  must  be  made  of  the  wool 
and  cotton  fibers  occurring  in  the  sample.  In  consideration  of  the  fact 
that  wool  possesses  about  twice  the  cross-section  of  cotton,  it  becomes  a 


998  ANALYSIS   OF   FIBERS   AND    YARNS    IN   FABRIC 

rather  easy  matter  to  calculate  the  ratio  between  the  two,  by  means  of 
which  the  percentage  by  weight  can  be  readily  obtained,  provided  that  the 
specific  gravity  of  wool  is  taken  to  be  about  the  same  as  that  of  cotton, 
which  is  approximately  true. 

2.  Analysis  of  Yams  in  Cloth. — Dale  ( Textile  World)  gives  the  following 
scheme  for  the  analysis  of  cloth  for  yarn  count:  A  sample  of  the  cloth 
having  an  area  of  3-5-0  sq.  yd.  (4.32  sq.  ins.)  is  weighed  in  grains.  This 
sample  can  be  cut  in  any  shape  desired,  but  a  rectangular  form,  1.8  ins.  by 
2.4  ins.,  is  the  most  convenient.  For  large  patterns  the  weight  of  3^0  sq.  yd. 
is  calculated  from  the  weight  of  a  larger  sample. 

The  grain  weight  of  3-00^  sq.  yd.  and  the  number  of  warp  and  filling 
threads  per  inch  having  been  determined,  the  "  straight  line  "  calculations 
are  made  as  follows: 

1.  Average  cotton  yarn  number  =  threads  per  inch -r- grains  per  3^^  sq.  yd. 

The  cotton  yarn  number  of  any  particular  group  of  threads  can  be  determined  by 
the  same  method  after  counting  and  weighing  separately. 

2.  Average  cotton  yarn  number  =  (threads  per  inch  X square  yards  per  poimd)  -i-23g. 

3.  Average  cotton  yarn  number  =  (threads  per  inch  X 24) -^  (ounces  per  square 
yard  X 35). 

4.  Ounces  per  running  yard  52^  ins.  wide  =  grains  per  3-g-Q  sq.  yd.,  no  calculation 
being  necessary. 

5.  Ounces  per  running  yard  =  (grains  per  -3^  sq.  yd.  Xwidth  in  inches)  -i- 52 1. 

6.  Ounces  per  square  yard  =  (grains  per  -g-g-Q  sq.  yd.  X36)  -j-52|. 

7.  Ounces  per  square  yard  =  (grains  per  -3^  sq.  yd.  X300)  -r-437§. 

8.  Grains  per  square  yard  =  7000 -^ square  yards  per  pound. 

9.  Square  yards  per  pound  =  16 -bounces  per  square  yard. 

10.  Square  yards  per  pound  =  840-^ (36 X grains  per  -g-g-Q  sq.  yd.). 

11.  Square  yards  per  pound  =  7000 -4- (300 X grains  per  -g-g-g-  sq.  yd.). 

12.  Running  yards  per  pound  =  840 -j- (width  in  inchesXgrains  per  -g-g-g-  sq.  yd.). 

13.  Woolen  runs  =  cotton  yarn  number XO. 521. 

14.  Worsted  yarn  number  =  cotton  yam  number X If. 

15.  Linen  lea  or  woolen  cut  =  cotton  yarn  number  X2.8. 

The  spun  yarn  number  is  calculated  for  cotton,  woolen,  worsted  and  linen  from 
the  finished  yarn  number  by  allowing  for  changes  that  may  have  occurred  in  length 
and  weight.  In  the  following  formula;  these  changes  are  expressed  by  the  yield  of 
finished  cloth  in  percentage.  Thus,  if  the  spun  yarn  shrinks  10  percent  in  length  or 
weight  in  weaving  and  finishing,  the  yield  of  finished  cloth  is  90  percent.: 

16.  Spun  yarn  number  =  finished  yarn  number -;- yield  percent  in  length. 

17.  Spun  yarn  number  =  finished  yarn  number  Xyield  percent  in  weight. 

18.  Spun  yarn  number  =  (finished  yarn  number  Xyield  percent  in  weight) -Xyield 
percent  in  length. 

3.  Determination  of  the  Size  of  Yams. — Yarns  are  classified  as  coarse 
or  fine  according  to  their  relative  thickness  or  weight  per  given  length. 
This  is  known  as  the  size  or  count  of  the  yarn.  There  are  a  large  number 
of  different  standards  employed  for  determining  the  numbers  of  yarns 
depending  on  the  character  of  the  fiber  (wool,  silk,  cotton,  linen,  etc.)  and 
on  the  locality  in  which  the  yarns  are  spun.     The  English  system  for 


DETERMINATION   OF   THE  SIZE  OF   YARNS 


999 


numbering  woolen,  worsted,  and  cotton  yarns  is  the  most  extensively 
employed  throughout  the  world,  while  for  the  numbering  of  silk  yarns  the 
French  system  is  used  chiefly  on  the  European  continent. 

The  determination  of  the  count  of  a  yarn  is  based  upon  one  of  two 
methods:  (a)  the  weight  of  a  definite  length  of  the  yarn,  in  which  case 
the  weight  of  the  standard  length  is  designated  as  the  yarn  number; 
this  method  is  principally  employed  in  the  case  of  silk;  (6)  the  length 
of  a  definite  weight  of  the  yarn,  in  which  case  the  numbers  will  depentl 
on  the  system  of  v/eights  adopted;  the  English  system  employing  the 
English  weights,  and  the  metric  system  using  the  metric  weights.  This 
method  is  used  for  yarns  of  wool,  cotton,  spun  silk,  linen,  etc. 

In  the  English  standards  for  various  fibers,  No.  1  yarn  has  the  following 
yards  per  pound: 

Cotton 840  yards 

Linen 300      " 

Woolen 1600      " 

Worsted 560      " 

Spun  silk 840      " 

The  following  table  gives  the  equivalent  counts  of  the  different  yarns 
for  the  same  weight  per  yard : 


Cotton  (Hanks 
of  840  Yards) . 

Linen  (Cuts  of 
300  Yards). 

Woolen  (Runs 
of  1600  Yards). 

Worsted  (Hanks 
of  560  Yards). 

Thrown  SUk 

(Yards  in  One 

Ounce). 

1 

0.357 

1.9 

0.66 

0.019 

2.8 

1 

5.3 

1.85 

0.053 

0.525 

0.187 

1 

0.346 

0.01 

1.5 

0.54 

2.85 

1 

0.029 

52.5 

18.7 

100.0 

34.6 

1 

The  apparatus  employed  for  determining  the  weight  of  the  prescribed 
length  of  yarn  may  be  an  ordinary  balance  or  scales,  though  special  yarn 
balances  are  made  with  arcs  variously  graduated  according  to  the  system 
of  counts  desired,  thus  giving  the  size  of  the  yarn  as  a  direct  reading. 

It  is  to  be  regretted  that  there  is  not  a  uniform  system  for  numbering 
yarns,  for  at  the  present  time  the  matter  is  in  a  rather  chaotic  state, 
each  fiber  having  its  own  special  system,  and  these  systems  also  varying 
widely  in  different  localities.  There  have  been  many  attempts  recently 
made  to  introduce  the  metric  system  of  numbering  as  being  a  convenient 
and  logical  one,  but  without  any  marked  degree  of  success.  It  has  also 
been  proposed  to  adopt  a  simple  English  standard  in  which  the  unit 
of  length  would  bo  1000  yds.  and  the  unit  of  weight  1  lb,  then  the  count 
of  the  yarn  would  indicate  the  number  of  1000-yd.  units  contained  in 


1000  ANALYSIS   OF  FIBERS  AND   YARNS  IN   FABRICS 

1  lb.  by  weight.  Such  a  system  would  greatly  simplify  the  present  com- 
plicated methods  of  yarn  counting.  But  owing  to  the  fact  that  reels  and 
testing  apparatus  have  been  made  in  conformity  with  the  present  standard 
sizes,  and  that  the  prices  paid  for  the  manufacture  of  yarns  are  based  on 
specified  numbers,  any  radical  change  in  the  systems  of  yarn  numbering 
would  entail  a  complete  readjustment  throughout  the  textile  industry; 
consequently  any  attempt  at  sudden  change  of  system  is  doomed  to  failure. 
It  has  been  found  that  tests  on  yarn  for  determining  the  count  in  the 
condition  received  vary  somewhat  according  to  the  moisture  in  the  sample 
and  the  humidity  of  the  atmosphere  at  the  time  of  testing.  Thus  it  was 
found  that  for  a  sample  of  normal  gray  cotton  yarn  tested  throughout  a 
period  of  three  months  the  moisture  varied  from  6  to  10  percent.  Assum- 
ing the  yam  to  have  been  40's,  this  corresponds  to  an  apparent  variation 
between  41 's  and  39's.  With  respect  to  the  influence  of  humidity  on 
strength  tests  on  wool,  cotton,  and  linen  cloths,  it  was  shown  that  the 
strength  depends  to  a  considerable  extent  upon  the  conditions  of  the 
atmosphere  to  which  the  cloth  is  exposed  prior  to  testing.  Pieces  were 
cut  into  six  strips  in  the  direction  of  the  warp  and  tested  for  strength  in 
the  same  direction  under  various  conditions  as  to  variation  in  the  relative 
humidity  of  the  atmosphere  and  the  average  strength  of  the  samples  from 
the  six  strips  was  also  taken.  An  ordinary  gray  cotton  drill  and  a  linen 
canvas  showed  an  increase  or  decrease  in  strength  according  as  there  was  an 
increase  or  a  decrease  in  the  relative  humidity  of  the  atmosphere;  the 
difference  in  strength  varj-ing  as  much  as  12  and  18  percent,  respectively. 
A  wool  cloth  serge  showed  a  decrease  or  increase  in  strength  with  increase 
or  decrease  in  the  relative  humidity  of  the  atmosphere,  the  results  in 
this  case  varying  as  much  as  14  percent.  The  necessity  of  adopting 
some  uniform  conditions  of  humidity  and  probably  also  of  temperature 
under  which  the  test  should  be  carried  out  is  thus  emphasised,  and  materials 
should  not  be  rejected  as  not  being  in  agreement  with  the  specifications 
unless  reliable  tests  have  been  made  under  conditions  of  humidity  and 
temperature  which  are  stated  and  agreed  upon  in  the  specifications  to 
which  the  sample  of  cloth  is  supposed  to  apply. 

The  general  principle  underlying  the  determination  of  the  yarn  number 
is  to  reel  off  the  yarn  in  hanks  of  a  definite  number  of  yards  (English 
system)  or  meters  (Metric  system),  and  then  determine  the  weight  of 
these  hanks;  the  number  of  such  hanks  required  to  give  the  standard 
weight  determines  the  count  of  the  yarn. 

The  number  of  yards  of  the  various  yarns  that  weigh  the  following 
amount  in  grains,  is  the  English  count  of  that  yarn: 

Cotton  yarn 8 .  330  grains 

Woolen  yarn 4 .  375      ' ' 

Worsted  yarn 12 .  500      " 

Linen  yarn 23 .  330      " 


SIZE  OF  COTTON  YARNS 


1001 


4.  Size  of  Cotton  Yams. — The  number  or  count  ^  of  cotton  yarn  is 
determined  by  the  number  of  hanks  of  840  yds.  each  contained  in  1  lb. 
This  is  the  basis  of  the  EngHsh  system  and  is  in  use  throughout  England, 
America,  Germany,  India,  and  Switzerland.  The  French  method  of 
numbering  is  based  on  the  decimal  system,  and  the  count  means  the 
number  of  hanks  each  1000  meters  in  length  required  to  weigh  500  grams. 
To  pass  from  the  French  (metric)  system  into  the  English,  and  conversely, 
use  the  following  factors : 

English  count  =  French  count  XI.  18. 

French  count  =  English  count X 0.847. 

The  Belgian  method  of  counting  is  to  use  the  number  of  840-yd.  hanks 
in  500  grams.  The  Austrian  system  is  the  number  of  hanks  of  950  ells 
each  contained  in  500  grams.  Doubled  or  twisted  yarns  are  designated 
in  the  same  manner  as  single  yarns,  except  that  the  number  of  threads  is 
also  given,  for  instance,  if  two  single  threads  of  count  20  are  twisted 
together,  the  yarn  is  described  as  2-20's  or  ^"o  or  20/2;  a  three-ply  yarn 
would  be  3-20's  or  ^  or  2  30,  etc.  According  to  the  number  of  threads 
twisted  together,  yarns  will  lose  from  2.5  to  6  percent  of  their  length 
in  doubling,  and,  of  course,  become  correspondingly  thicker.  Yarns  con- 
taining more  than  two  single  threads  are  known  as  sewing  twist  or  cord. 

In  order  to  avoid  the  necessity  of  reeling  off  such  a  large  quantity  as 
840  yds.,  the  hank  is  divided  into  7  leas  of  120  yds.  each.  The  standard 
reel  employed  has  a  circumference  of  1^  yds.  (54  ins.),  hence  a  lea  (or  lay) 
is  equivalent  to  80  turns  of  the  reel.    "We  have  the  following  relations: 

1  thread  =  1|  yds. 
80  threads  - 1  lea  =  120  yds. 
7  leas  =  1  hank =840  yds. 


COMPARATIVE 

TABLE  OF  FRENCH  AND  ENGLISH  YARN  NUMBERS 

French. 

English. 

French. 

EngUsh. 

French. 

Enghsh. 

French. 

English. 

1 

1.18 

11 

12.1 

21 

24.8 

32 

37.8 

2 

2.23 

12 

14.2 

22 

26.0 

34 

40.1 

3 

3.54 

13 

15.3 

23 

27.2 

36 

42.5 

4 

4.72 

14 

16.5 

24 

28.3 

38 

44.8 

5 

5.90 

15 

17.7 

25 

29.5 

40 

47.2 

6 

7.80 

16 

18.9 

26 

30.7 

45 

52.1 

7 

8.26 

17 

20.1 

27 

31.8 

50 

59.0 

8 

9.44 

18 

21.2 

28 

33.0 

55 

64.9 

9 

10.62 

19 

22.4 

29 

34.2 

60 

70.8 

10 

11,80 

20 

23.6 

30 

35.4 

In  England  the  count  of  yarn  is  frequently  called  the  "grist." 


1002 


ANALYSIS  OF  FIBERS  AND  YARNS  IN  FABRICS 


The  finest  number  of  cotton  yarn  to  be  met  with  in  commerce  is  240; 
numbers  higher  than  this  have  rarely  been  spun  in  any  amounts.  Up 
to  20's  the  counts  rise  by  single  numbers,  such  as  1,  2,  3,  4,  5,  etc.  Beyond 
20's  it  is  customary  to  make  use  of  only  the  even  numbers,  like  22,  26, 
30,  etc.  Above  60's  the  numbers  rise  by  5,  such  as  65,  70,  75,  etc.,  and 
above  lOO's  they  rise  by  10.  The  coarsest  yarns  used  for  weaving  are 
6's  and  8's;  though  yarns  of  coarser  count  than  these  are  employed  for 
lamp-wicks,  cordage,  etc. 

The  following  variations  above  and  below  the  exact  standard  repre- 
senting the  counts  of  various  yarns  are  allowed: 

Percent. 

1.  Cotton  yarns  Nos.  1  to  10,  EngHsh 2.5 

Waste  yarn,  including  so-called  "imitation"  yarns,  up  to 

No.  6 4.0 

Cotton  yarns  Nos.  11  to  20 2.0 

Nos.  21  to  40 2.5 

"  above  No.  40 3.0 

2.  Worsted  yarn 1.5 

3.  Carded  yarn 2.5 

Shoddy  from  wool 4.0 

4.  Mixed  wool  and  cotton  yarn 2.5 

silk 1.5 

5.  Linen  yarn 2.5 

6.  Jute  yarn 3.0 


The  following  table  shows  the  comparative  length  of  different  counts 
of  cotton  yarn: 


No. 

Yards 

per 
Pound. 

Weight 

per  1000 

Yards, 

Ounces. 

No. 

Yards 

per 
Poimd. 

Weight 

per  1000 

Yards, 

Ounces. 

No. 

Yards 

per 
Pound. 

Weight 

per  1000 

Yards, 

Ounces. 

4 

6 

8 

10 

12 

14 

3,360 
5,040 
6,720 
8,400 
10,080 
11.760 

4.76 
3.18 
2.38 
1.90 
1.59 
1.39 

16 
18 
20 
24 
28 
32 

13,440 
15,120 
16,800 
20,160 
23,520 
26,880 

1.19 

1.065 

0.952 

0.795 

0.695 

0.595 

36 
40 
44 
50 
60 
80 

30,240 
33,600 
36,960 
42,000 
50,440 
67,200 

0,517 
0.476 
0.433 
0.380 
0.317 
0.238 

SIZE  OF   COTTON  YARNS 


1003 


The  following  table  gives  the  counts  of  cotton  yarns  by  the  weight  in 
grains  of  1  skein  of  120  yds. : 


120  Yards 

Count 

120  Yards 

Count 

120  Yards 

Count 

120  Yards 

Count 

Weigh, 

of 

Weigh, 

of 

Weigh, 

of 

Weigh, 

of 

Grains. 

Yarn. 

Grains. 

Yarn. 

Grains. 

Yarn. 

Grains. 

Yarn. 

1 

1000 

15 

67 

27 

37 

50 

20 

2 

500 

15.5 

65 

27.5 

36.5 

52 

19 

3 

333 

16 

63 

28 

36 

54 

18.5 

4 

250 

16.5 

61 

28.5 

35 

56 

18 

5 

200 

17 

59 

29 

34.5 

58 

17 

5.5 

181 

17.5 

57 

29.5 

34 

62 

16 

6 

167 

18 

56 

30 

33.5 

66 

15 

6.5 

154 

18.5 

54 

30.5 

33 

70 

14 

7 

143 

19 

53 

31 

32.5 

74 

13.5 

7.5 

133 

19  5 

51 

31.5 

32 

78 

13 

8 

125 

20 

50 

32 

31 

83 

12 

8.5 

118 

20.5 

49 

33 

30 

91 

11 

9 

111 

21 

48 

34 

29.5 

100 

10 

9.5 

105 

21.5 

47 

35 

29 

111 

9 

10 

100 

22 

45 

36 

28 

125 

8 

10.5 

95 

22.5 

44 

37 

27 

143 

7 

11 

91 

23 

43 

38 

26 

167 

6 

11.5 

87 

23.5 

42 . 5 

39 

25.5 

200 

5 

12 

83 

24 

42 

40 

25 

250 

4 

12.5 

80 

24.5 

41 

41 

24.5 

334 

3 

13 

77 

25 

40 

42 

24 

500 

2 

13.5 

74 

25.5 

39 

44 

23 

1000 

1 

14 

71 

26 

38 

46 

22 

14.5 

69 

26.5 

37.5 

48 

21 

A  short  method  of  determining  the  count  of  cotton  yarn  when  only  a 
short  length  is  available  is  to  weigh  off  in  grains  12  yds.  of  the  yarn,  and 
divide  this  number  into  100.  Thus,  if  12  yds.  weigh  5  grains,  the  count  is 
100  H- 5  =  20. 

To  obtain  the  yards  'per  ounce  of  any  cotton  yarn  multiply  the  yarn 
count  by  the  factor  52|;  for  instance:  30's  cotton  yarn  is  equivalent  to 
30  ^52^  =  1575  yds.  per  ounce.  The  calculation  can  be  shortened  by 
adding  5  percent  more  to  one-half  the  yarn  count  and  multiplying  by  100; 
for  example:  30's  count  equals  15+0.75  =  15.75X100  =  1575  yds.  per 
ounce. 


1004 


ANALYSIS   OF   FIBERS   AND   YARNS   IN   FABRICS 


5.  Woolen  Yams. — The  English  system  numbering  of  woolen  yarns 
is  based  on  the  numl)er  of  "  rmis  "  in  1  lb.;  a  "  run  "  is  1600  yds.  As  this 
h\  equivalent  to  100-yd.  lengths  to  1  oz.,  the  run  system  is  very  convenient 
for  calculating  the  weight  of  yarns  in  ounces;  thus,  Ij  runs  is  equivalent 
to  125  yds.  per  ounce.  The  following  table  gives  the  "  runs  "  or  count 
of  woolen  yarns  by  the  weight  in  grains  of  20  yds.: 


20  Yards 

20  Yards 

20  Yards 

20  Yards 

20  Yards 

Weigli, 

Runs. 

Weigh, 

Runs. 

Weigh, 

Runs. 

Weigh, 

Runs. 

Weigh, 

Runs. 

Grains. 

Grains. 

Grains. 

Grains. 

Grains. 

1 

87.5 

21 

4.2 

41 

2.13 

61 

1.43 

81 

1.08 

2 

43.7 

22 

4.0 

42 

2.08 

62 

41 

82 

1.07 

3 

29  2 

23 

3.8 

43 

2.03 

63 

38 

83 

1.05 

4 

21.9 

24 

3.6 

44 

1.99 

64 

37 

84 

1.04 

5 

17.5 

25 

3.5 

45 

1.94 

65 

35 

85 

1.03 

6 

14.6 

26 

3.4 

46 

1.90 

66 

33 

80 

1.02 

7 

12.5 

27 

3.2 

47 

1.86 

67 

31 

87 

1.01 

8 

10.9 

28 

3.1 

48 

1.82 

68 

29 

88 

0.99 

9 

9.7 

29 

3.0 

49 

1.79 

69 

27 

89 

0.98 

10 

8.7 

30 

2.9 

50 

1.75 

70 

25 

90 

0.97 

11 

7.9 

31 

2.S 

51 

1.72 

71 

23 

91 

0.96 

12 

7.3 

32 

2.7 

52 

1.68 

72 

22 

92 

0.95 

13 

6.7 

33 

2.6 

53 

1.65 

73 

20 

93 

0.94 

14 

6.2 

34 

2.6 

54 

1.62 

74 

18 

94 

0.93 

15 

5.8 

35 

2.5 

55 

1.59 

75 

17 

95 

0.92 

16 

5.5 

36 

2.4 

56 

1.56 

76 

15 

96 

0.91 

17 

5.2 

37 

2.36 

57 

1.54 

77 

14 

97 

0.90 

18 

4.9 

38 

2.30 

58 

1.51 

78 

12 

98 

0.89 

19 

4.6 

39 

2.24 

59 

1.48 

79 

11 

99 

0.88 

20 

4.4 

40 

2.19 

60 

1.46 

80 

09 

100 

0.87 

In  the  metric  or  international  system  the  count  of  woolen  yarn  is  the 
number  of  hanks  of  1000  meters  weighing  1  kilogram. 

In  the  American  system  the  "  cut  "  is  frequently  used  for  the  count 
of  woolen  yarns.  This  is  based  on  the  number  of  cuts  of  300  yds.  in 
1  lb.  In  the  grain  system  the  count  is  designated  by  the  weight  in  grains 
of  20  yds. 


WOOLEN  YARNS 


1005 


6.  Worsted  Yams. — The  numbering  of  worsted  yarns  by  the  English 
system  is  based  on  the  number  of  "  hanks  "  of  560  yds.  in  1  lb.  The 
following  table  gives  the  count  of  worsted  yarns  by  the  weight  in  grains 
of  20  yds. : 


20 
Yards 

No. 

of 

Yarn. 

20 
Yards 

No. 

of 

Yarn. 

20 
Yards 

No. 

of 

Yarn. 

20 
Yards 

No. 

of 

Yarn. 

20 
Yards 

No. 

of 

Yarn. 

Weigh, 
Grains. 

Weigh, 
Grains. 

Weigh, 
Grains. 

Weigh, 
Grains. 

Weigh, 
Grains. 

1 

250 

23 

10.87 

45 

5.56 

67 

3.73 

89 

2.81 

2 

125 

24 

10.42 

46 

5.43 

68 

3.68 

90 

2.78 

3 

83.33 

25 

10 

47 

5.32 

69 

3.62 

91 

2.75 

4 

62.50 

26 

9.62 

48 

5.21 

70 

3.57 

92 

2.72 

5 

50 

27 

9.26 

49 

5.10 

71 

3.52 

93 

2.69 

6 

41.67 

28 

8.93 

50 

5.00 

72 

3.47 

94 

2.66 

7 

35.71 

29 

8.62 

51 

4.90 

73 

3.42 

95 

2.63 

8 

31.25 

30 

8.33 

52 

4.81 

74 

3.38 

96 

2.60 

9 

27.78 

31 

8.06 

53 

4.72 

75 

3.33 

97 

2.58 

10 

25 

32 

7.81 

54 

4.63 

76 

3.29 

98 

2.55 

11 

22 .  73 

33 

7.58 

55 

4.55 

77 

3.25 

99 

2.52 

12 

20.83 

34 

7.35 

56 

4.46 

78 

3.21 

100 

2.50 

13 

19.23 

35 

7.14 

57 

4.39 

79 

3.17 

105 

2.38 

14 

17.86 

36 

6.94 

58 

4.31 

80 

3.12 

110 

2.27 

15 

16.67 

37 

6.76 

59 

4.24 

81 

3.09 

115 

2.17 

16 

15.62 

38 

6.58 

60 

4.17 

82 

3.05 

120 

2.08 

17 

14.71 

39 

6.41 

61 

4.10 

83 

3.01 

125 

2.00 

18 

13.89 

40 

6.25 

62 

4.03 

84 

2.98 

150 

1.67 

19 

13 .  16 

41 

6.10 

63 

3.97 

85 

2.94 

175 

1.43 

20 

12 .  .50 

42 

5.95 

64 

3.91 

86 

2.91 

200 

1.25 

21 

11.90 

43 

5.81 

65 

3.85 

87 

2.87 

22 

11.36 

44 

5.68 

66 

3.79 

88 

2.84 

The  count  of  worsted  yarns,  where  only  short  lengths  are  available, 

may  be  determined  by  dividing  150  by  the  weight  in  grains  of  12  yds.; 

hence  if  12  yds.  weigh  5  grains,  the  count  would  be  150-^5  =  30.     Also  this 

formula  may  be  used: 

yards  weighed 

Count  =  777^5 .  1  ,  • : — . 

0.08  weight  m  grams 

Five  different  systems  are  used  in  France  for  numbering  worsted  yarn : 

Yards  per 
Pound. 

Roubaix,  old 708 

Roubaix,  new 354 

Fourmies 352 

Reims 347 

Metric 496 


1006 


ANALYSIS  OF  FIBERS  AND  YARNS  IN  FABRICS 


The  first  four  of  these  are  used  in  the  mills  of  France,  while  the  fifth 
is  the  metric  system,  by  which  French  yarn  is  usually  numbered  when 
offered  for  sale  to  foreign  buyers.  To  reduce  the  metric  nmnber  to  the 
worsted  count  based  on  560  yds.  per  pound:  Multiply  the  metric  number 
by  0.886.  To  reduce  the  worsted  number  (560  yds.  per  pound)  to  the 
metric  count:  Multiply  the  worsted  number  (560  yds.  per  pound)  by 
1.129. 

7.  Silk  Yams.— The  fineness  or  size  of  raw  silk  thread  is  expressed 
by  a  number  known  as  litre  (in  French)  or  titolo  (in  Italian);  this  gives 
(ho  number  of  units  of  certain  weight  (denier  =  53. 13  mgms.)  a  skein  of 
cM'tain  length  will  weigh.  Several  different  standards  are  in  use  in  Europe 
;  t  the  present  time,  among  which  are  the  following: 


Denier  (Italian,  legal) . 

Denier  {Milan) 

Denier  ( Turin) 

Old  denier  (Lyons) . . . 
New  denier  (Lyons) . . 
Denier  (international) 


Weight  in  Grams. 

Length  in  Meters. 

0.0.5 

450 

0.051 

476 

0.0534 

476 

0.0531 

476 

0.0531 

500 

0.05 

500 

The  titre  is  usually  expressed  in  the  form  of  a  fraction,  representing 
limits  of  variation,  as  all  skeins  are  not  of  absolutely  the  same  size.  A 
silk  marked  if,  for  instance,  would  mean  that  it  varied  from  18  to  20 
deniers. 

The  denier  is  supposed  to  be  derived  from  the  weight  of  a  Roman  coin 
of  small  value  called  denarius.  The  abbreviation  for  pence  (d)  in  the 
English  monetary  system  is  derived  also  from  this  word.  The  origin 
and  history  of  the  denier  are  quite  interesting.  The  denier  was  a  small 
coin,  originally  of  silver,  and  was  introduced  into  Gaul  by  the  Romans, 
probably  about  the  time  of  Caesar's  Gallic  wars.  The  value  of  this  piece 
was  about  16  cents.  Later,  the  name  denier  was  applied  to  both  gold 
and  copper  coins  as  well.  It  is  claimed  that  it  was  the  latter  which  was 
originally  used  as  a  weight,  but  this  is  uncertain.  However,  the  denier, 
whichever  it  was,  weighed  24  grains  Poids  de  Marc.  The  old  method 
of  grading  silk  was  to  take  80  skeins  of  120  aunes  (giving  a  total  length 
of  9600  aunes)  and  find  their  weight  in  deniers.  Toward  the  end  of  the 
eighteenth  century,  one  Matley,  observing  that  the  grain  was  or  of  the 
denier,  conceived  the  idea  of  taking  skeins  of  400  aunes  (or  2t  of  9600) 
and  weighing  these  in  grains,  thus  preserving  the  ratio.  He  made  a 
machine  for  measuring  these  skeins  of  400  aunes.     The  trade  accepted 


SILK  YARNS  1007 

the  change^  but  could  not  get  rid  of  the  old  term  denier,  which  now  became 
fastened  to  the  new  grain  weight,  so  that  the  denier  weight  as  we  know 
it  to-day,  is  really  a  1-grain  Poid  de  Marc,  and  2T  of  its  original  value. 
The  present  denier  has  a  value  of  0.0531  gram  =  0.833  grain,  and  the  400 
aunes  skein  is  equal  to  476  meters  =  520  yds.  and  20  ins. 

The  international  denier  (adopted  by  the  International  Yarn  Number- 
ing Congress,  held  in  Vienna  in  1873)  may,  perhaps,  be  more  conveniently 
defined  as  being  the  weight  (in  grams)  of  10,000  meters.  The  basis  for  the 
sizing  of  thrown  silk  in  England  and  the  United  States  is  the  weight  in 
drams  of  1000  yds.  To  convert  this  weight  into  deniers,  it  is  necessary  to 
multiply  by  the  factor  33.36.  For  example,  if  1000  yds.  of  silk  weigh 
3  drams,  it  would  be  equivalent  to  33.36X3  =  100.08  deniers.  In  France 
the  size  of  the  silk  is  usually  expressed  in  terms  of  the  old  denier,  which 
was  the  weight  in  deniers  of  400  French  ells.  The  latter  length  is  equiva- 
lent to  476  meters,  and  the  denier  is  equal  to  0.05313  gram.  Hence,  to 
obtain  the  size  in  deniers  according  to  this  system,  multiply  the  weight  in 
grams  of  476  meters  by  the  factor  18.82  (  =  1^0.05313).  For  example, 
if  476  meters  of  silk  weigh  5  grams,  this  would  be  equivalent  to  5X18.82  = 
94.1  deniers.  To  obtain  the  deniers  under  the  new  measure,  the  weight 
in  grams  of  500  meters  is  multiplied  by  the  factor  18.82.  The  legal  measure 
in  France  of  the  size  of  silk  is  represented  by  the  weight  in  grams  of  500 
meters,  but  it  is  probably  more  usual  to  express  the  size  in  terms  of  deniers. 
To  convert  the  new  denier  into  the  old  denier,  multiply  by  the  factor 

/     476\ 
0.9521  =F7v7j/-     The  denier  on  the  old  system  may  be  converted  into  the 

international  measure  (based  on  a  weight  of  0.05  gram  for  a  length  of  500 
meters)  by  multiplying  by  the  factor  1.116;  and,  inversely,  the  inter- 
national denier  may  be  converted  into  the  old  system  denier  by  multiply- 
ing by  the  factor  0.896. 

To  determine  the  length  per  pound  of  a  given  size  of  silk  divide 
4,465,000  yds.  by  the  number  of  deniers  and  the  result  will  be  yards  per 
pound. 

In  the  numbering  of  silk  yarns  the  denier  system  is  used  for  raw  silk 
and  the  dram  system  is  used  for  thrown  silk  in  the  United  States.  A 
1-denier  silk  would  measure  4,464,528  yds.  per  pound,  and  a  fl-denier 
(average  15)  would  measure  tV  of  this,  and  so  on.  A  1-dram  silk  measure 
256,000  yds.  per  pound,  and  a  2-dram  silk  would  be  ^  of  this,  and  so  on. 
Consequently  to  reduce  deniers  to  drams  divide  the  deniers  by  the  factor 
17.44. 

The  following  tables  show  the  relations  between  the  different  measures 
of  the  French  scale: 


1008 


ANALYSIS   OF  FIBERS  AND  YARNS  IN   FABRICS 


SILK  YARNS 


1009 


Legal 

New 

Old 

Internat. 

Legal 

New 

Old 

Internat. 

Titer. 

Denier. 

Denier. 

Denier. 

Titer. 

Denier. 

Denier. 

Denier. 

Weight 

Weight 

Weight 

Weight 

Weight 

Weight 

Weight 

Weight 

of  500 

of  500 

of  476 

of  10,000 

of  500 

of  500 

of  476 

of  10,000 

Meters  in 

Meters  in 

Meters  in 

Meters  in 

Meters  in 

Meters  in 

Meters  in 

Meters  in 

Grams. 

Deniers. 

Deniers. 

Grams. 

Grams. 

Deniers. 

Deniers. 

Grams. 

8.1 

152.45 

145.13 

162 

10.1 

190.09 

180.97 

202 

8.2 

154.33 

146.92 

164 

10.2 

191.98 

182.76 

204 

8.3 

156 . 22 

148.71 

166 

10.3 

193.86 

184.55 

206 

8.4 

158.10 

150.50 

168 

10.4 

195.74 

186.35 

208 

8.5 

159.98 

152.30 

170 

10.5 

197.62 

188.14 

210 

8.6 

161.86 

154.08 

172 

10.6 

199.51 

189.93 

212 

8.7 

163.74 

155.88 

174 

10.7 

201.39 

191.72 

214 

8.8 

165.63 

157.67 

176 

10.8 

203.27 

193.51 

216 

8.9 

167.51 

159.46 

178 

10.9 

205.15 

195.30 

218 

9.0 

169.39 

161.25 

180 

11.0 

207.03 

197.10 

220 

9.1 

171.27 

163.04 

182 

11.1 

208.92 

198.09 

222 

9.2 

173.16 

164.84 

184 

11.2 

210.80 

200.68 

224 

9.3 

175.04 

166.63 

186 

11.3 

212.68 

202.47 

226 

9.4 

176.92 

168.42 

188 

11.4 

214.56 

204.26 

228 

9.5 

178.80 

170.21 

190 

11.5 

216.45 

206.06 

230 

9.6 

180 .  68 

172.00 

192 

11.6 

218.33 

207.85 

232 

9.7 

182.57 

173.80 

194 

11.7 

220.21 

209.64 

234 

9.8 

184 . 45 

175.59 

196 

11.8 

222.09 

211.43 

236 

9.9 

186.33 

177.38 

198 

11.9 

223.97 

213.22 

238 

10,0 

188.21 

179.17 

200 

12.0 

225.86 

215.01 

240 

Dorgin  (American  Silk  Journal)  gives  the  following  tables  for  Japan 
silk,  Tsatlee  silk,  and  Tussah  silk  yarns: 


1010 


ANALYSIS  OF  FIBERS  AND  YARNS  IN  FABRICS 


Japan  Silk  Yarn 

This  table  is  based  on  the  customary  13/15  denier  raw  silk,  or  the  15   denier  full 
thrown  silk;  the  allowance  for  loss  in  boil-off  is  25  percent. 


Thread. 

Japan  Tram  in  Gum 

Japan  Tram  in  Boil-off. 

Denier. 

Yards  per  Pound. 

Denier. 

Yards  per  Pound . 

2 

30 

148,818 

22.50 

198,423 

3 

45 

99,212 

33.75 

132,282 

4 

60 

74,409 

45.00 

99,212 

5 

75 

59,527 

56.25 

79,369 

6 

90 

49,606 

67.50 

66,141 

7 

105 

42,512 

78.75 

56,922 

8 

120 

37,204 

90.00 

49,606 

9 

135 

33,071 

101.25 

44,094 

10 

150 

29,764 

112.50 

39,685 

11 

165 

27,058 

123.75 

36,077 

12 

180 

24,803 

135.00 

33,071 

13 

195 

22,895 

146.25 

30,217 

14 

210 

21,260 

157.50 

28,346 

15 

225 

19,842 

168.75 

26,456 

Tsatlee  Silk  Yarn 


This  table  is  based  on  single  25's  denier  full  thrown  silk;   the  allowance  for  boil-off 
is  25  percent. 


Tsatlee  Tram  in  Gum. 

Tsatlee  Tram  in  Boil-off. 

Thread. 

Denier. 

Yards  per  Pound, 

Denier. 

Yards  per  Pound. 

2 

50 

89,291 

37.50 

119,054 

3 

75 

59,527 

56.25 

79,369 

4 

100 

44,645 

75.00 

59,527 

5 

125 

35,716 

93.75 

47,622 

6 

150 

29,764 

112.50 

39,685 

7 

175 

25,512 

131.25 

34,015 

8 

200 

22,323 

150.00 

29,764 

9 

225 

19,842 

168.75 

26,456 

10 

250 

17,858 

187.50 

23,811 

SILK  YARNS 


1011 


TussAH  Silk  Yarn 

This  table  is  based  on  8-cocoon  single  40  denier  full  thrown  silk;    the  allowance 
for  boil-ofif  is  25  percent. 


Tussah  Tram  in  Gum 

Tussah  Tram  in  Boil-off. 

Thread. 

Denier. 

Yards  per  Pound. 

Denier. 

Yards  per  Poimd. 

2 

80 

55,807 

60 

74,409 

3 

120 

37,204 

90 

49,606 

4 

160 

27,903 

120 

37,204 

5 

200 

22,323 

150 

29,764 

6 

240 

18,602 

180 

24,803 

7 

280 

15,045 

210 

21,260 

8 

320 

13,952 

240 

18,602 

9 

360 

12,401 

270 

16,535 

10 

400 

11,161 

300 

14,882 

The  following  table  shows  the  comparison  between  drams,  grams,  and 
deniers : 


Drams. 

Grams. 

Deniers 

Drams. 

Grams. 

Deniers. 

0.0299 

0.05313 

1.0 

2.50 

4.43 

83.4 

0.25 

0.44 

8.3 

2.75 

4.87 

91.6 

0.50 

0.88 

16.5 

3.00 

5.31 

100.0 

0.568 

1.00 

18.82 

4.00 

7.09 

133.0 

0.75 

1.33 

25.0 

5.00 

8.86 

166.0 

1.00 

1 . 771875 

33.36 

6.00 

10.63 

199.0 

1.25 

2.21 

41.6 

7.00 

12.40 

233.0 

1.50 

2.65 

50.0 

8.00 

14.17 

265.0 

1.75 

3.10 

58.3 

9.00 

15.95 

299.0 

2.00 

3.54 

66.6 

10.00 

17-.  72 

333.0 

2.25 

3.98 

75.0 

To  convert  the  new  international  titer  into  any  of  the  older  standards 
multiply  by  the  following  factors: 

To  Turin  titer  X 0.8931 

To  Milan  titer  X 0.9315 

To  French  titer  X 0.8964 

To  Italian  (legal)  and  Swiss  titer X 0.9000 

Conversely,  to  convert  any  of  the  above  old  titers  into  the  new  international 
equivalent,  divide  by  the  above  factors. 
Conversion  factors  in  silk  numbering: 


1012 


ANALYSIS  OF   FIBERS  AND   YARNS  IN   FABRICS 


2776- 

^  deniers 

=  runs 

5289- 

^  deniers 

=  cotton  number 

7932- 

i-  deniers 

=  worsted  number 

160- 

^  drams 

=  runs 

305- 

^  drams 

=  cotton  number 

457- 

^  deniers 

=  worsted  number 

2776- 

^runs 

=  deniers 

5289- 

-^  cotton  number 

=  denier 

7932- 

^  worsted  number 

=  denier 

160- 

^  runs 

=  drams 

305- 

-cotton  number 

=  drams 

457- 

^  worsted  number 

=  drams 

deniers X  0.0576 

=  drams 

drams  XI 7. 352 

=  deniers 

For  the  sizing  of  spun  silk  the  unit  of  the  English  scale  is  a  hank  of 
840  yds.,  and  the  number  of  such  hanks  in  1  lb.  is  the  count  of  the  yarn. 
There  is  a  difference  in  the  counting  of  doubled  spun  silk  from  that  of 
doubled  cotton  yarn,  in  that  with  cotton  "  2-40's  "  means  single  40's 
doubled  to  20's;  whereas,  with  spun  silk  "  2-40's  "  means  single  80's 
doubled  to  40's,  and  "  3-40's  "  would  mean  single  120's  tripled  to  40's,  etc. 

In  France  and  Switzerland  the  number  or  size  of  spun  silk  indicates 
the  number  of  skeins  of  1000  meters  in  1  kilogram.  To  convert  the 
English  number  into  the  French  or  metric  number  multiply  by  the  factor 
1.69;  and  to  convert  the  French  number  into  the  English  number  multiply 
by  the  factor  0.59. 

Dorgin  ^  gives  the  following  table  for  the  sizing  of  spun  silk  yarns : 

SPUN  SILK  YARNS 


Count . 

2-  or  More- Ply, 

Count. 

2-  or  More-Ply, 

Yds.  to  Lb.  in  Gray. 

Yds.  to  Lb.  in  Gray. 

2 

1,680 

24 

20,160 

3 

2,520 

26 

21,840 

4 

3,360 

28 

23,520 

6 

5,040 

30 

25,200 

8 

6,720 

32 

26,880 

9 

7,560 

34 

28,560 

10 

8,400 

36 

30,240 

12 

10,080 

40 

33,600 

14 

11,760 

42 

35,280 

15 

12,600 

48 

40,320 

16 

13,440 

54 

45,360 

18 

15,120 

60 

50,400 

20 

16,800 

72 

60,480 

21 

17,640 

75 

63,000 

22 

18,480 

80 

67,200 

1  American  Silk  Journal. 


SILK  YARNS 


1013 


On  colored  spun  silks  an  allowance  of  about  5  percent  on  the  above 
measurements  should  be  made  for  contraction  in  length  of  the  silk  in  the 
processes  of  dyeing. 

Sewing  silk  is  numbered  irregularly  by  letters,  000,  00,  O,  A,  B,  C, 
D,  E,  EE,  F,  FF,  G.  The  yards  in  one  ounce  for  the  respective  letters 
are  2000,  1600,  1300,  1000,  850,  650,  550,  400,  330,  262,  212,  and  125. 

Thrown  silk  in  Europe  is  graded  in  the  same  manner  as  raw  silk,  but 
with  American  and  English  throwsters  the  adopted  custom  of  specifying 
the  counts  of  raw  silk  yarns  is  to  give  the  weight  of  a  hank  of  1000  yds. 
in  drams  avoirdupois;  thus,  if  such  a  hank  weighs  5  drams,  it  is  technically 
known  as  5-dram  silk.  The  size  of  yarn  is  always  given  for  the  "  gum 
weight  ";  that  is,  its  condition  before  boiling-off.  In  this  latter  process 
yarns  lose  from  15  to  30  percent,  according  to  the  class  of  raw  silk  used, 
Chinese  silks  losing  the  most  and  Japanese  and  European  silks  the  least. 
The  following  table  shows  the  number  of  j^ards  to  the  pound  and  ounce 
of  silk  of  different  dram  sizes.  The  number  of  yards  per  pound  being 
based  on  a  pound  of  gum  silk: 


LENGTH  OF  GUM  SILK  YARN  PER  POUND  AND  PER  OUNCE 


Drams  per 

Yards  per 

Yards  per 

Drams  per 

Yards  per 

Yards  per 

1000  Yards. 

Pound. 

Ounce. 

1000  Yards. 

Pound. 

Ounce. 

1 

256,000 

16,000 

9 

28,444 

1778 

u 

204,800 

12,800 

9* 

26,947 

1684 

U 

170,666 

10,667 

10 

25,600 

1600 

If 

146,286 

9,143 

11 

23,273 

1455 

2 

128,000 

8,000 

12 

21,333 

1333 

2i 

113,777 

7,111 

13 

19,692 

1231 

21 

102,400 

6,400 

14 

18,286 

1143 

2| 

93,091 

5,818 

15 

17,067 

1067 

3 

85,333 

5,333 

16 

16,000 

1000 

3i 

78,769 

4,923 

17 

15,058 

941 

3^ 

73,143 

4,571 

18 

14,222 

889 

31 

68,267 

4,267 

19 

13,474 

842 

4 

64,000 

4,000 

20 

12,800 

800 

4i 

60,235 

3,765 

21 

12,190 

762 

41 

56,889 

3,556 

22 

11,636 

727 

4f 

53,368 

3,368 

23 

11,130 

696 

5 

51,200 

3,200 

24 

10,667 

666 

5^ 

46,545 

2,909 

25 

10,240 

640 

6 

42,667 

2,667 

26 

9,846 

615 

61 

39,385 

2,462 

27 

9,481 

592 

7 

36,571 

2,286 

28 

9,143 

571 

7i 

34,133 

2,133 

29 

8,827 

551 

8 

32,000 

2,000 

30 

8,533 

533 

8^ 

30,118 

1,882 

1014  ANALYSIS  OF   FIBERS   AND   YARNS   IN   FABRICS 

Another  method  of  sizing  silk  yarns  which  is  sometimes  used  is  the 
ounce  system.  This  system  is  mostly  used  in  connection  with  other  trades 
than  weaving  and  knitting,  and  where  thick  counts  of  yarn  are  employed; 
The  system  is  based  on  the  weight  in  ounces  of  a  1000-yd.  hank.  We 
thus  have  three  methods  of  sizing  thrown  silk: 

1.  Denier  system.    2.  Dram  system.    3.  Ounce  system. 

To  ascertain  the  equivalent  count  of  a  given  yarn  in  any  of  these 
systems,  proceed  as  follows : 

(a)  Denier  to  dram  X  0.058. 

(6)  Denier  to  ounce  X  0.0036. 

(c)  Dram  to  denier  X 17^. 

(d)  Dram  to  ounce  X  0.0625. 

(e)  Ounce  to  denier X277|. 
(/)  Ounce  to  dram  X 16. 

To  convert  the  count  of  raw  silk  into  the  equivalent  for  spun  silk: 

(a)  Denier  system  into  spun  silk  count  — 5282 -^deniers  =  spun  silk 
count,  and  5282 -h  spun  silk  count  =  deniers. 

(6)  Dram  system  into  spun  silk  count  —  304.7  -^  drams  =  spun  silk  count, 
and  304.7 -^  spun  silk  count  =  drams. 

(c)  Ounce  system  into  spun  silk  count— 19.4 bounces  =  spun  silk  count, 
and  19.4 -i- spun  silk  count  =  ounces. 

The  average  limits  within  which  the  sizes  of  various  grades  of  silks 
fluctuate  are: 

Raw  silk 9  to    30  deniers 

Organzine 18  to    34  *    " 

Tram 24  to    60 

Wild  silk 100  to  300       " 

During  the  process  of  reeling  the  cocoon  filaments,  the  latter  may,  for 
one  reason  or  another,  run  out  previous  to  starting  another  cocoon;  or  to 
make  up  for  the  cocoons  left  out  during  the  reeling,  the  operator  may  add 
extra  cocoons.  From  such  conditions  it  will  easily  be  understood  that  it  is 
practically  impossible  to  produce  a  thread  of  absolute  uniformity  through- 
out the  entire  skein.  Owing  to  this  variation  in  the  size  of  silk,  in  order 
to  obtain  accurately  the  size  of  any  lot  of  silk  under  consideration,  it  is 
necessary  to  take  the  average  of  several  tests  from  different  parts  of  the 
bale.  These  irregularities  in  silk  make  it  necessary  in  commercial  transac- 
tions to  permit  a  variation  of  two  deniers  in  any  lot  of  silk. 

The  following  table  shows  the  sizes  of  silk  yarns  in  deniers  as  com- 
pared with  the  sizes  of  cotton  yarns  (English  system) : 


SILK  YARNS 


1015 


COMPARATIVE  TABLE  OF  COUNTS  OF  COTTON  AND  SILK  YARNS  OF 

EQUIVALENT  SIZE 


Cotton. 

Silk. 

Single. 

Double. 

Yards 
per  Pound. 

Drams. 

Deniers. 

16-1 

32-2 

13,440 

17.04 

296.83 

18-1 

36-2 

15,120 

16.89 

294.22 

20-1 

40-2 

16,800 

15.24 

265.48 

22-1 

44-2 

18,480 

13  86 

241.44 

24-1 

48-2 

20,160 

12.69 

221.00 

26-1 

52-2 

21,840 

11.72 

204 . 16 

28-1 

56-2 

23,520 

10.88 

189 . 52 

30-1 

60-2 

25,200 

10.20 

177.68 

32-1 

64-2 

26,880 

9.52 

165.83 

34^1 

68-2 

28,560 

8.96 

156.08 

36-1 

72-2 

30,240 

8.46 

147.37 

38-1 

76-2 

31,920 

8.02 

139.70 

40-1 

80-2 

33,600 

7.62 

132.75 

42-1 

84-2 

35,280 

7.26 

126.46 

44-1 

88-2 

36,960 

6.92 

120.54 

46-1 

92-2 

38,640 

6.62 

115.32 

48-1 

96-2 

40,320 

6.34 

110.44 

50-1 

100-2 

42,000 

6.08 

105.91 

52-1 

104-2 

43,680 

5.86 

102.08 

54-1 

108-2 

45,360 

5.64 

98.24 

56-1 

112-2 

47,040 

5.44 

94.76 

58-1 

116-2 

48,720 

5.25 

91.45 

60-1 

120-2 

50,400 

5.08 

88.48 

62-1 

124-2 

52,080 

4.92 

85.90 

64-1 

128-2 

53,760 

4.76 

82.91 

66-1 

132-2 

55,440 

4.62 

80.48 

68-1 

136-2 

57,120 

4.48 

78.04 

70-1 

140-2 

58,800 

4.35 

75.77 

72-1 

144-2 

60,480 

4.23 

73.68 

74-1 

148-2 

62,160 

4.12 

71.77 

76-1 

152-2 

63,840 

4.01 

69.85 

78-1 

156-2 

65,520 

3.91 

68.11 

80-1 

160-2 

67,200 

3.81 

66.37 

82-1 

164-2 

68,880 

3.72 

64.80 

84-1 

168-2 

70,560 

3.63 

63.23 

86-1 

172-2 

72,240 

3.55 

61.84 

88-1 

176-2 

73,920 

3.46 

60.27 

90-1 

180-2 

75,600 

3.39 

58.95 

92-1 

184-2 

77,280 

3.31 

57.65 

94-1 

188-2 

78,960 

3.24 

56.44 

96-1 

192-2 

80,640 

3.18 

55.39 

98-1 

196-2 

82,320 

3.11 

54.17 

100-1 

200-2 

84,000 

3.05 

53.13 

102-1 

204-2 

85,680 

2.90 

52.08 

104-1 

208-2 

87,360 

2.93 

51,04 

106-1 

212-2 

89,040 

2.88 

50.16 

108-1 

216-2 

90,720 

2.82 

49.12 

110-1 

220-2 

92,400 

2.77 

48.25 

112-1 

224-2 

94,080 

2.72 

47.48 

114-1 

228-2 

95,760 

2.67 

46.51 

116-1 

232-2 

97.440 

2.63 

45.81 

118-1 

236-2 

99.120 

2.58 

44.94 

120-1 

240-2 

100,800 

2.54 

44.24 

1016 


ANALYSIS  OF  FIBERS   AND  YARNS   IN   FABRICS 


8.  Artificial  Silk  Yarns. — The  size  or  count  of  artificial  silk  is  expressed 
in  deniers  corresponding  to  the  number  of  grams  in  a  length  of  9000  meters. 
This  is  very  close  to  the  Lyons  denier. 

Dorgin  ^  gives  the  following  table  for  the  counts  of  artificial  silk: 

Artificial  Silk 


Yards 

Yards 

Yards 

Yards 

Denier. 

per  Pound. 

Denier. 

per  Pound. 

Denier. 

per  Pound. 

Denier. 

per  Pound. 

50 

89,201 

150 

29,764 

250 

17,858 

350 

12,756 

60 

74,409 

160 

27,903 

260 

17,171 

360 

12,401 

70 

63,779 

170 

26,262 

270 

16,535 

370 

12,066 

80 

55,807 

180 

24,803 

280 

15,945 

380 

11,749 

90 

49,606 

190 

23,497 

290 

15,395 

390 

11,447 

100 

44,645 

200 

22,323 

300 

14,882 

400 

11,161 

110 

40,587 

210 

21,260 

310 

14,402 

450 

9,921 

120 

37,204 

220 

20,293 

320 

13,952 

500 

8,929 

130 

34,342 

230 

19,411 

330 

13,529 

550 

8,118 

140 

31,889 

240 

18,602 

340 

13,131 

600 

7,441 

Artificial  silk  involves  the  question  of  specific  gravity  which  cannot 
be  compared  with  the  specific  gravity  of  real  silk;  artificial  silk,  as  well 
known,  will  cover  less  for  a  given  unit  than  real  silk,  for  which  reason 
allowance  must  be  made  for  this  property. 

The  following  table  gives  the  corresponding  counts  of  yarns  of  similar 
size  (yards  per  pound)  of  artificial  silk,  thrown  silk,  cotton  and  spun 
silk: 

Cotton  2-ply,  3-ply,  and  4-ply  has  5,  ^,  and  j  the  number  of  hanks  and 
yardage  per  pound  its  counts  and  numbers  indicate.  For  instance, 
1/10  =  4200  yds.  to  the  pound,  3/10  =  2800  yds. 

Spun  silk  in  2-ply,  3-ply,  etc.,  has  the  number  of  hanks  per  pound  and 
yardage  its  count  indicates.  For  instance,  10/1  =  8400  yds.  to  pound, 
10/2  the  same,  etc. 

Thrown  silk  loses  in  dyeing,  in  average  25  percent,  hence  1  lb.  or  16 
ozs.  gray  will  give  12  ozs.  dyed,  pure  dye,  making  it  necessary  to  add  33^ 
percent  to  the  gum  or  gray  yards  per  pound  to  obtain  the  dyed  yardage 
per  pound  of  16  ounces:  thus,  46  drams  5565  yds.  per  gum  pound,  plus 
33|  percent  =  1855  =  7420  yds.  per  dyed  pound. 

^  American  Silk  Journal 


ARTIFICIAL  SILK  YARNS 


1017 


Cotton  and  Spun  Silk 

Artificial  Silk.           | 

Thrown  Silk.                      | 

Singles, 

840  Yards  per  Hank. 

Yards 

Yards 

Yards 

Yards 

Deniers. 

per 

Drams. 

per  Pound 

per  Pound 

No. 

per 

Pound. 

in  Gum. 

in  Boil-off. 

Pound. 

60 

74,409 

4^ 

56,889 

75,852 

90 

75,600 

70 

63,779 

51 

47,628 

63,504 

76 

63,840 

80 

55,806 

6i 

41,796 

55,728 

66 

55,440 

90 

49,606 

61 

37,236 

49,648 

60 

50,400 

100 

44,645 

7f 

33,572 

44,762 

54 

45,360 

110 

40,587 

81 

30,568 

40,757 

48 

40,320 

120 

37,204 

9J- 

28,055 

37,407 

46 

38,640 

130 

34,342 

91 

25,924 

34,565 

41 

34,440 

140 

31,890 

101 

23,814 

31,752 

38 

31,920 

150 

29,764 

m 

22,260 

29,680 

35 

29,400 

160 

27,903 

m 

20,898 

27,864 

33 

27,720 

170 

26,662 

13 

19,692 

26,256 

31 

26,040 

180 

24,803 

13f 

18,618 

24,824 

29 

24,360 

190 

23,497 

14^ 

17,655 

23,540 

28 

23,520 

200 

22,323 

15i 

16,786 

22,381 

27 

22,680 

210 

21,260 

16 

16,000 

21,333 

26 

21,840 

220 

20,293 

16f 

15,284 

20,378 

24 

20,160 

230 

19,411 

17§ 

14,628 

19,504 

23 

19,320 

240 

18,602 

m 

14,028 

18,704 

22 

18,480 

250 

17,858 

19 

13,474 

17,965 

21 

17,640 

260 

17,171 

20 

12,800 

17,067 

20 

16,800 

270 

16,535 

20f 

12,337 

16,449 

280 

15,945 

2U 

11,907 

15,876 

19 

15,960 

290 

15,395 

22 

11,636 

15,515 

18 

15,120 

300 

14,882 

23 

11,130 

14,840 

310 

14,401 

231 

10,894 

14,525 

17 

14,280 

320 

13,951 

241 

10.449 

13,932 

16 

13,440 

330 

13,529 

25 

10,240 

13,653 

340 

13,131 

26 

9,846 

13,128 

350 

12,756 

261 

9,663 

12,883 

15 

12,600 

360 

12,401 

271 

9,309 

12,412 

370 

12,066 

281 

8,983 

11,977 

380 

11,749 

29 

8,827 

11,769 

14 

11,760 

390 

11,447 

30 

8,533 

11,378 

400 

11,161 

301 

8,393 

11,191 

13 

10,920 

450 

9,921 

341 

7,421 

9,894 

12 

10,080 

500 

8,929 

38 

6,737 

8,983 

11 

9,240 

550 

8,117 

42 

6,095 

8,127 

10 

8,400 

600 

7,441 

46 

5,565 

7,420 

9 

7,560 

1018 


ANALYSIS  OF  FIBERS   AND   YARNS  IN   FABRICS 


9.  Linen,  Jute,  etc. — The  count  of  linen  yarn  is  based  on  the  number 
of  "  cuts  "  of  300  yds.  in  1  lb.  The  following  table  gives  the  counts  of 
linen  yarns  by  the  weight  in  grains  of  300  yds.  (or  "  cut  ") : 


300 
Yards 
Weigh, 
Grains. 

Number 

of 

Yarn. 

300 

Yards 
Weigh, 
Grains. 

Number 

of 

Yarn. 

300 
Yards 
Weigh, 
Grains. 

Number 

of 

Yarn. 

300 
Yards 
Weigh, 
Grains. 

Number 

of 

Yarn. 

300 
Yards 
Weigh, 
Grains. 

Number 

of 

Yarn. 

100 

70.00 

300 

23.33 

490 

14.29 

680 

10.29 

1250 

5.60 

110 

63.64 

310 

22.58 

500 

14.00 

690 

10.14 

1300 

5.38 

120 

58.33 

320 

21.87 

510 

13.73 

700 

10.00 

1400 

5.00 

130 

53.85 

330 

21.21 

520 

13.46 

725 

9.66 

1500 

4.67 

140 

50.00 

340 

20.59 

530 

13.21 

750 

9.33 

1600 

4.37 

150 

46.67 

350 

20.00 

540 

12.96 

775 

9.03 

1700 

4.12 

160 

43 .  75 

360 

19.44 

550 

12.73 

800 

8.75 

1800 

3  89 

170 

41.18 

370 

18.92 

560 

12.50 

825 

8.48 

1900 

3.68 

180 

38.89 

380 

18.42 

570 

12.28 

850 

8.24 

2000 

3.50 

190 

36.84 

390 

17.95 

580 

12.07 

875 

8.00 

2250 

3.11 

200 

35.00 

400 

17.50 

590 

11.86 

900 

7.78 

2500 

2.80 

210 

33.33 

410 

17.07 

600 

11.67 

925 

7.57 

2750 

2.55 

220 

31.82 

!     420 

16.67 

610 

11.48 

950 

7.37 

3000 

2.33 

230 

30.43 

430 

16.28 

620 

11.29 

975 

7.18 

3250 

2.15 

240 

29.17 

440 

15.91 

630 

11.11 

1000 

7.00 

3500 

2.00 

250 

28.00 

450 

15.56 

640 

10.94 

1050 

6.67 

4000 

1.75 

260 

26.92 

460 

15.22 

650 

10.77 

1100 

6.36 

5000 

1.40 

270 

25.93 

470 

14.89 

660 

10.61 

1150 

6.09 

6000 

1.17 

280 

25.00 

480 

14.58 

670 

10.45 

1200 

5.83 

7000 

1.00 

290 

24.14 

In  determining  the  count  of  bleached  linen  yarns  a  loss  for  bleaching  is 
allowed,  as  follows:  full  bleach,  20  percent;  three-fourth  bleach,  18  percent; 
half  bleach,  15  percent. 

Linen  yarns  are  classified  into  hand-spun  and  machine-spun,  and  are 
also  characterised  as  dry-  or  wet-spun.  Dry-spun  yarns  are  possessed  of  a 
greater  degree  of  firmness,  though  finer  numbers  can  be  obtained  by  wet- 
spinning.  Tow  yarns  are  made  from  the  waste  of  flax  spinning  and  are  readily 
distinguished  from  linen  yarns  by  the  numerous  knots  and  shives  which  are 
present.  Linen  yarns  are  made  from  hackled  flax  while  tow  yarns  are  spun 
from  carded  flax  waste.  In  Germany  dry-spun  yarns  range  from  10  to  30's, 
and  wet-spun  yarn  up  to  80's.  Yarns  as  fine  as  200  are  spun  in  Belgium  and 
Scotland.     Tow  yarns  are  dry-spun  from  6  to  20,  and  wet-spun  up  to  35. 

The  count  of  linen  yarn  may  also  be  obtained  from  the  formula: 

yards  weighed 
0 .  043  X  weight  in  grains' 

In  England  there  is  a  difference  in  the  method  of  numbering  wet-spun 
and  dry-spun  flax  yarns.     In  the  former  the  bases  is  1  lea  of  300  yds., 


COMPARISON   OF  YARN  SIZES 


1019 


and  the  j^arn  size  is  the  number  of  leas  in  1  lb.  weight,  as  given  above. 
But  in  dry-spun  flax  (also  for  jute)  the  count  is  based  on  the  spyndle  of 
14,400  yds.  (48  cuts  of  300  yds.),  and  the  size  or  "  grist  "  is  the  weight  in 
pounds  of  1  spyndle.  In  other  words,  in  the  case  of  wet-spun  flax,  the 
count  increases  as  the  yarn  gets  finer,  the  weight  of  1  lb.  being  the  fixed 
quantity.  For  dry-spun  flax,  however,  the  count  increases  as  the  yarn 
gets  coarser,  and  the  fixed  quantity  is  the  length  of  14,400  yds.^ 

Jute  yarns  are  numbered  in  the  same  manner  as  linen  yarns,  the  basis 
also  being  the  number  of  cuts  (or  leas)  of  300  yds.  in  1  lb.  In  Holland 
the  count  of  jute  yarns  is  given  bj^  the  number  of  hectograms  (0.22  lb.) 
in  a  length  of  150  meters. 

The  count  of  jute  yarns  is  also  based  on  the  weight  in  pounds  per 
spindle  of  14,400  yds.  That  is  to  say,  if  14,400  yds.  of  the  yarn  weigh 
8  lbs.  the  count  is  8. 

Hemp  is  reckoned  on  the  same  basis  as  jute. 

Ramie  yarns  are  numbered  like  chappe.  silk  in  Europe,  that  is  to  say, 
the  count  denotes  the  number  of  hanks  of  1000  meters  weighing  1  kilogram; 
hence  a  ramie  yarn  of  32  count  would  be  equivalent  to  20's  in  the  cotton 
count.     The  same  method  of  numbering  prevails  in  America. 

10.  Comparison  of  Yam  Sizes. — The  following  table  gives  the  compari- 
son between  the  different  English  systems  of  yarn  counts: 


Name  of  Sj'stem. 

Unit  Length  and 

Name. 

Count  of  Yarn  Determined  by 

Cotton 

840  vds.  =  1  hank 

Number  of  hanks  in  1  lb. 

Silk 

840  vds.  =  1  hank 

Number  of  hanks  in  1  lb. 

Worsted 

560  yds.  =  1  hank 
256  yds.  =  1  skein 

Number  of  hanks  in  1  lb. 

Woolen  (Yorkshire) . 

Number  of  skeins  in  1  lb. 

Linen 

300  yds.  =  1  lea 

Number  of  leas  in  1  lb. 

American  cut 

300  yds.  =  1  cut 

Number  of  cuts  in  1  lb. 

American  run 

100  yds.  per  ounce 

=  1  run 

Number  of  runs  X 10  in.  1  lb. 

American  grain 

20  yds.  per  grain  = 

1  grain 

Weight  in  grains  of  20  yds. 

Jute 

14,400  yds.  =  1  spy 

ndle 

Weight  in  pounds  of  14.400  yds. 

'  The  3'arn  table  for  wet-spun  flax  is: 

90  ins.  (once  around  the  reel)  =  1  thread  =  2i  yds. 
120  threads  =  1  lea  =  300  yds. 
10  leas  (English  reeling)  =  1  hank  =  3000  yds. 
12  leas  (Scotch  or  Irish  reeling)  =  1  hank  =  3600  j'ds. 
20  English  hanks  =  1  bundle  =  60,000  yds. 
I63  Scotch  or  Irish  hanks  =  1  bundle  =  60,000  yds. 
For  dry-spun  flax  (and  jute) : 

90  ins.  (once  around  the  reel)  =1  thread  =  21  j-ds. 
120  threads  =  1  cut  (lea)  =300  yds. 
2  cuts       =  1  heer  =  600  yds. 
12  cuts       1  hank  (hasp)  =3600  yds. 
48  cuts  or  4  hanks  =  1  spyndle  =  14,400  yds. 


1020 


ANALYSIS  OF   FIBERS   AND  YARNS   IN   FABRICS 


Silk 

in  the  Gum, 

1000  Yards 

per  Skein. 

Silk,  Boiled, 
Half  Skeins, 
500  Yards. 

Cotton 

(Singles)  and 

Spun  Silk, 

840  Yards 

per  Hank. 

Yards. 

Worsted 
(Singles), 
560  Yards 
per  Hank. 

Woolen 

(Singles), 

1200  Yards 

per  Run. 

Linen 
(Singles), 
300  Yards 

per  Lea 
(or  Woolen 
by  Cuts). 

Yards 

Yards 

Yards 

Yards 

Yards 

Leas 

Yards 

Drams. 

per 

Drams. 

per 

^o. 

per 

No. 

per 

P.uns. 

per 

or 

per 

Pound. 

Pound. 

Pound. 

Pound. 

Pound. 

Cuts. 
1 

Pound. 

300 

300 

560 

1 

560 

o 

600 

1 

840 

840 
1,000 

2 

1,120 

■    3 

900 

2 

1,680 

1,000 

3 

1.680 

i 

1,000 

5 

1.500 

64 

2,000 

3 

2,520 

2,000 

4 

2,240 

U 

2,000 

7 

2,100 

421 

2,994 

4 

3,360 

3,000 

5 

2,800 

2 

3,200 

10 

3,000 

32 

4,000 

5 

4,200 

4,000 

7 

3,920 

25 

4,000 

13 

3,900 

255 

5,019 

6 

5,040 

5,000 

9 

5,040 

3 

4,800 

17 

5,100 

2U 

0,024 

7 

5,880 

6,000 

11 

0,100 

3i 

6,000 

20 

6,000 

18i 

7,014 

8 

6,720 

7,000 

12 

6,720 

45 

7,200 

23 

6,900 

16 

8,000 

10 

8,400 

8,000 

14 

7,840 

o 

8,000 

27 

8,100 

141 

8,678 

11 

9,240 

9,000 

10 

8,900 

55 

8,800 

30 

9,000 

12f 

10,039 

12 

10,080 

10.000 

18 

10,080 

e>i 

10,000 

33 

9,900 

111 

10,894 

13 

10,920 

11,000 

20 

11,200 

7 

11,200 

37 

11,100 

105 

12,190 

14 

11,700 

12,000 

21 

11,700 

75 

12,000 

40 

12,000 

91 

13,128 

10 

13,140 

13,000 

23 

12,880 

8 

12,800 

43 

12,900 

9i 

13,838 

17 

14,280 

14,000 

25 

14,000 

Si 

14,000 

47 

14,100 

Si 

15,059 

18 

15,120 

15,000 

27 

15,120 

95 

15,200 

50 

15,000 

8 

16,000 

19 

15,900 

16,000 

29 

10,240 

10 

16,000 

53 

15,900 

75 

17,007 

20 

10,800 

17,000 

30 

10,800 

105 

10,800 

57 

17,100 

7 

18,286 

21 

17,040 

18,000 

32 

17,920 

Hi 

18,000 

60 

18,000 

Of 

18,963 

23 

19,320 

19,000 

34 

19,040 

12 

19,200 

63 

18,900 

05 

19,692 

24 

20,160 

20,000 

30 

20,100 

125 

20,000 

67 

20,100 

5f 

22,201 

20 

21,840 

22,000 

40 

22,400 

14 

22,400 

74 

22,200 

105 

24,381 

5i 

24,381 

28 

23,520 

24,000 

42 

23,520 

15 

24,000 

80 

24,000 

9J 

26,25(3 

5 

25,600 

30 

25,200 

20,000 

46 

25,700 

10 

25,600 

80 

25,800 

91 

27,670 

45 

28,444 

34 

28,560 

28,000 

50 

28,000 

18 

28,800 

94 

28,200 

8i 

30,118 

4i 

30,118 

36 

30,240 

30,000 

54 

30,240 

19 

30,400 

100 

30,000 

8 

32,000 

4 

32,000 

38 

31,920 

32,000 

58 

32,480 

20 

32,000 

106 

31,800 

7J 

34,133 

3i 

34,133 

40 

33,600 

34,000 

00 

33,600 

21 

33,000 

114 

34,200 

7 

30,571 

35 

30,571 

42 

35,280 

30,000 

64 

35,840 

22 

35,200 

120 

30,000 

6J 

37,920 

46 

38,640 

38,000 

68 

38,080 

24 

38,400 

120 

37,800 

6i 

39,385 

3i 

39,385 

48 

40,330 

40,000 

72 

40,320 

25 

40,000 

134 

40,200 

6 

42,007 

3 

42,667 

50 

42,000 

42,000 

76 

42,560 

26 

41,600 

140 

42,000 

5J 

44,522 

52 

43,680 

44,000 

78 

43,680 

28 

44,800 

146 

43,800 

oi 

46,545 

2i 

46,545 

54 

45,360 

40,000 

82 

45,920 

29 

40,400 

154 

40,200 

5i 

48,702 

58 

48,720 

48,000 

86 

48,160 

30 

48,000 

160 

48,000 

5 

51,200 

25 

51,200 

60 

50,400 

50,000 

90 

50,400 

31 

49,600 

166 

49,800 

4i 

52,512 

02 

52,080 

52,000 

92 

51,520 

32 

51,200 

174 

52,200 

4i 

53,895 

04 

53,760 

54,000 

96 

53,760 

34 

54,400 

180 

54,000 

4i 

55,351 

2i 

56,889 

00 

55,440 

56,000 

100 

56,000 

35 

5(),000 

186 

.55,800 

41 

58,514 

70 

58,800 

58,000 

104 

58,240 

30 

57,000 

194 

58,200 

4i 

60,235 

72 

60,480 

00,000 

lOS 

60,480 

38 

00,800 

200 

60,000 

4i 

62,000 

74 

02,160 

02,000 

110 

61,600 

39 

62,400 

200 

61,800 

4 

64,000 

2 

64, 000 

76 

03,840 

04,000 

114 

63,840 

40 

04,000 

214 

64,200 

3J 
3i 

66,005 
68,267 

78 

05  520 

00,000 
68,000 

118 

66,080 
68,320 

41 

05  600 

''20 

66  000 

Silk  Fi 

atures. 

SO 

07!200 

122 

42 

07,200 

220 

67,800 

3J 

70,021 

iu  Gur 

1,  1000 

84 

70,560 

70,000 

120 

70,. 560 

44 

70,400 

234 

70,200 

Yards  p 

er  Skein. 

80 

72,240 

72,000 

128 

71,680 

45 

72,000 

240 

72,000 

3i 
3i 

73,142 

75,852 

88 

73,920 
75,600 

74,000 
76,000 

132 

73  O'^O 

40 

73,000 
76,800 

246 

73,800 
76,200 

Deniers. 

Yards 

90 

136 

76,160 

48 

254 

3i 

78,769 

per  Lb 

92 

77,280 

78,000 

140 

78,400 

49 

78,400 

260 

78,000 

54/56 

79,125 

90 

80,640 

80,000 

142 

79,520 

50 

80,000 

266 

79,800 

3i 

81,920 

62/54 

82,125 

98 

82,320 

82,000 

146 

81,760 

51 

81,000 

274 

82,200 

100 

84,000 

84,000 

150 

84,000 

52 

83,200 

280 

84,000 

3 

85,333 

50/52 

85,333 

102 

85,680 

80,000 

154 

80,240 

54 

86,400 

286 

85,800 

48/50 

88,750 

104 

87,360 

88,000 

158 

88,480 

55 

88,000 

294 

88,200 

2i 

89,043 

108 

90,720 

90,000 

160 

89,000 

50 

89,600 

300 

90,000 

2J 

93,091 

46/48 

92,666 

110 

92,400 

92,000 

164 

91,840 

58 

92,800 

306 

91,800 

21 

97,524 

44/46 

96,750 

114 

95,760 

90,000 

172 

90,320 

00 

96,000 

320 

96,000 

2i 

102,400 

42/44 

101,250 

120 

100,800 

100,000 

180 

100,800 

62 

99,200 

330 

99,000 

2i 

107,789 

40/42 

106,125 

130 

109,200 

110,000 

200 

112,000 

69 

110,400 

370 

111,000 

2i 

120,471 

36/38 

117,025 

142 

119,280 

120,000 

210 

117,000 

75 

120,000 

400 

120,000 

2 

128,000 

32/34 

132,000 

154 

129,360 

130,000 

230 

128,800 

80 

128,000 

430 

129,000 

li 

136,533 

30/32 

140,000 

100 

139,440 

140,000 

250 

140,000 

90 

144,000 

470 

141,000 

li 

146,280 
170,007 

28/30 
24/20 

150,000 
174,000 

178 
200 

149,520 
168,000 

1.50,000 
170,000 

U 

11 

180,182 

22/24 

189,250 

230 

193,200 

190,000 

2-ply,    3-ply   and 

i-ply    Co 

tton.    Worsted, 

li 

204,800 

20/22 

207,250 

240 

201,000 

200,000 

Woolen  and  I;inen  '^ 

iTarns,  ha 

ve  respectively 

li 

227,550 

18/20 

229,000 

270 

220,800 

225,000 

i,  i  and  j  the  numbei 

of  hank 

)  per  pound  and 

1 

250,000 

10/18 

250,000 

300 

252,000 

250,000 

yardage  their  counts 

or  numb 

ers  indicate. 

i 
J 

f 

1 

292,571 
341,333 
409,000 
512,000 
082,067 

14/10 

12/14 

10/12 

8/10 

0  8 

290,000 
334,750 
395,666 
483,500 
021,750 

300,000 
350,000 
400,000 
500,000 
600,000 

SrrN  Silk  Yarns, 
etc.,  have  the  numbe 
yardage  their  counts 
20/2,  ,30/2,  20/3,  30 

however 
r  of  hank 
indicate, 
/3,  etc. 

in  2-ply,  .3-ply, 
5  per  pound  and 
and  are  written 

4  0 

870,500 

800,000 

Corresponding  cou 

nts  and 

yardage  are  on 

i 

1.024,000 

1 

1,000,000 

the  same  line  runnin 

g  across 

the  tab 

le. 

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INDEX 


Abaca  fiber,  809 
Abassi  cotton,  390 
Absorbent  cotton,  463 
Absorbent  flax,  758 
Acetate  silk,  705 

dyeing  of,  707 
Acid  cellulose,  502,  534,  543 
Acid  dyes,  action  of  on  wool,  176 
Acid  finish  on  cotton  fabrics,  526 
Acid  in  cotton  fabrics,  testing  for,  521 
Acid    purification    factor    for    vegetable 

fibers,  353 
Acid-proof  cloth,  524 
Acidified  wool,  properties  of,  147 
Adarakiewitz's  test,  298 
Adansonia  fiber,  334 
Adenos  cotton,  393 
Adipo  cellulose,  509 
Adsorption  formula  for  wool,  149 
Adsorption  in  dyeing,  550 
African  cotton,  391 
African  fiber,  842 
Agave  fiber,  816 
Ailanthus  silk,  259 
Akund  floss,  659 
Alfa  fiber,  335 
Algodon  de  seda,  670 
Alkali-cellulose,  505,  581 
Aloe  fiber,  819 
Aloe  hemp,  893 
Aloes  vert,  819 
Alpaca,  78,  209,  220 

grading  of,  226 
Alpaca  fiber,  microscopy  of,  222 

suri  type  of,  223 
Alpaca  noils.  111 
Alpha-oxycellulose,  538 
Alumin,  575 
Ambari  hemp,  802 


American  cotton,  393 
American  mohair,  214 
American  wools,  shrinkage  of,  113 
Amiantho,  26 

Ammonio-copper    oxide,     action    of    on 
cellulose,  491 

preparation  of,  491 
Amphibole  asbestos,  29 
Amyloid,  498 
Anaphe  silk,  259 
Angora  goat,  209 
Animal  and  vegetable  fibers,  distinctions 

between,  9,  876 
Animal  fibers,  8 

colloidal  nature  of,  8 
Animalised  cotton,  730 
Anthrax,  from  handling  wool,  221 
Antiphlogin  for  artificial  silk,  676 
Apparatus  for  testing  elasticity  of  yarns, 

343 
Ardabil  wool,  51 
Arequipa  fleece,  221 
Argali  sheep,  41 
Argentine  wool,  49 
Arghan  fiber,  825 
Arsenic  in  woolen  goods,  125 
Artificial  fibers,  11 

rare  forms  of,  14 
Artificial  horsehair,  515,  724 
Artificial  lace,  726 
Artificial  leather  from  asbestos,  35 
Artificial  maline,  727 
Artificial  silk,  14 

acid  rotting  of,  711 

action  of  formaldehyde  on,  702 

action  of  water  on,  714 

bleaching  of,  712 

classification  of,  672 

comparison  of  various,  714 

comparison  of  with  silk,  674 


1035 


1036 


INDEX 


Artificial   silk,  cost   of   manufacture   of, 
718 

covering  power  of,  710,  713 

drying  of,  712 

dyeing  properties  of,  710 

fineness  of,  710 

identification  of,  933 

luster  of,  713 

microscopy  of,  718 

properties  of,  709,  712 

ribbon  straw  from,  725 

scrooping  of,  712 

statistics  of,  731 

stretch  spinning  of,  695 

ultramicroscopic  studies  of,  720 

uses  for,  674 
Artificial  silk  from  milk,  672 
Artificial  silk  yarn,  count  of,  1016 
Artificial  tulle,  726 
Artificial  wool,  183,  771 
Asbestos,  action  of  chemicals  on,  36 

composition  of,  24 

cross  fiber,  30 

crusher  for,  32 

fiberiser  for,  33 

grading  of,  30 

heat  resisting  power  of,  30 

mass  fiber,  31 

mineralogy  of,  27 

occurrence  of,  24 

shear  fiber,  31 

slip  fiber,  30 

statistics  of,  31 

varieties  of,  25 

water  of  constitution  in,  31 
Asbestos  and  cotton,  separation  of,  36 
Asbestos  cloth,  history  of,  25 
Asbestos  fabrics,  uses  of,  33 
Asbestos  fibers,  dimensions  of,  24 
Asbestos  textiles,  properties  of,  35 
Asbestos  yarn,  dyeing  of,  34 

spinning  of,  34 

numbering  of,  32 
Asclepias  cotton,  666 
Ash,  determination  of  in  vegetable  fibers, 

352 
Ashraouni  cotton,  390 
Assama  silk,  258 
Assili  cotton,  390 
Atlas  silk,  259 
Australian  mohair,  214 
Aztecs,  fibers  known  to,  2 


B 

Babylonians,  use  of  textiles  by,  2 

Baden  hemp,  793 

Badger,  fiber  of,  78 

Badger  fur,  240 

Baer  apparatus  for  cotton  sampling,  420 

Bahmia  Egyptian  cotton,  388 

Bakelite  for  metallising  yarn,  13 

Balso  fiber,  655 

Bamboo  fiber,  860 

Barbadoes  cotton,  376 

Basinetto  silk,  252 

Basketry  fiber,  330 

Bast  fibers,  320,  326,  864 

jointed  structure  of,  321 

microchemical  examination  on,  321 

physical  structure  of,  337 

reactions  of,  897 
Bastard  asbestos,  27 

Bastose,  distinction  of  from  cellulose,  767 
Bat,  fiber  of,  78 
Bauhinia  fiber,  332 
Bave,  249 
B.  A.  wools,  49 
Bayko  metal  yarn,  12 
Bayko  yarn,  708 
Beard-hair,  40 
Beaver,  fiber  of,  78 
Beaver  fur,  238 
Benders  cotton,  394 
Bestorite,  35 
Beta-oxycellulose,  538 
Bibliography  of  textile  fibers,  1021 
Black  bear  fur,  235,  239 
Blarina  fur,  240 
Blarina  tip  fur,  240 
Bleached  cotton,  acid  index  of,  983 

acid  value  of,  984 

analysis  of,  980 

copper  hydrate  value  of,  984 

copper  index  of,  982 

copper  number  of,  540 

copper  sulfate  value  of,  985 

copper  value  of,  984 

viscosity  test  of,  985 

wood-gum  value  of,  984 
Blending  of  wool,  109 
Blue  asbestos,  26 
Blue  bender  cotton,  480 
Blue  flax,  737 
Boar  bristles,  234 


INDEX 


1037 


Boil-ofT  losses  for  raw  silk,  292 

Boiled-off  liquor,  291 

Boiled-off  cotton,  analysis  of,  535 

Bombax  cotton,  655 

Botany  noil,  107 

Boweds  cotton,  377 

Bowstring  hemp,  833 

Brazilian  cotton,  397 

Breaking  length  of  fibers,  446 

Breislakite,  27 

Brightening  silk,  274 

Brilliant  yarns,  12 

Brins,  249 

Bristle-hair,  40 

British  wools,  classification  of  qualities  of, 

59 
Broom-grass  fiber,  330 
Brown  bat  fur,  240 
Brown  Egyptian  cotton,  389 
Brush  fibers,  329,  864 
Brush-hair,  40 
Buenos  Ayres  wool,  49 
Byssus  silk,  316 


Cajun  fibers,  818 

Calcino,  257 

Calcium    oxalate    crystals    in    vegetable 

fibers,  348 
Calf-hair,  231 

Calender  finish  on  cotton,  640 
Calender  finish  on  silk,  276 
Calender  for  Schreiner  finish,  641 
Calotropis  fiber,  662 
Camel,  fiber  of,  78 
Camel-hair,  209 

grading  of,  226 
Camel-hair  fiber,  227 
Camel-hair  noils.  111,  229 
Canada  lynx  fur,  235 
Canadian  asbestos,  24 
Canapa  piccola,  791 
Canebrake  cotton,  394 
Canton  gum  silk,  254 
Cape  mohair,  212 
Cape  noil,  107 
Cape  wool,  50 
Capillarity  of  fibers,  6 
Caraguata  fiber,  839 
Caravonica  cotton,  393,  890 
Carbon  percentage  in  vegetable  fibers,  353 
Carbohydrates,  490 


Carbon  filaments  from  cellulose,  503 
Carbonisation  of  shoddy,  186 
Carbonising,  effect  of  on  woolen  fabrics, 
120 

origin  of,  516 

use  of  aluminium  chloride,  191 

use  of  hydrochloric  acid,  190 

use  of  magnesium  chloride,  194 

use  of  sulfuric  acid,  188 
Carbonising  duster  for  wool  stock,  192 
Carbonising  machine  for  gas  process,  187 
Carbonising  machine  for  wool  stock,  191 
Carbonising  process  in  relation  to  cotton, 

502 
Carbonising  wool,  comparison  of  different 

methods  for,  195 
Carded  cotton  yarn,  444 
Carded  silk,  270 
Carpasian  linen,  26 
Carpet  wool,  65 
Casein  silk,  709 

Caseinate  of  lime  for  waterproofing  fab- 
rics, 562 
Cashmere,  209,  216 
Cat  fur,  235 
Cat-hair,  232 
Catone  di  Vetro,  11 
Caulking  fibers,  331 

Caustic  soda,  plant  for  recovery  of  in  mer- 
cerising, 625 
Cauto  cotton,  656 
Ceara  cotton,  397 
Ceiba  cotton,  656,  888 
Celanese  silk,  705 
Cellestron  silk,  705 
Cellon,  708 
Cellophane,  708 
Cellulo  silk,  691 
Celluloid,  523 
Cellulose,  490 

action  of  alkalis  on,  505 

action  of  metallic  salts  on,  508 

action  of  zinc  chloride  on,  503 

amino  compound  of,  535 

chemical  constitution  of,  493 

chemical  reactions  of,  498 

copper  value  of,  541 

determination  of  in  vegetable  fibers, 
352 

esters  of,  506 

hydration  of,  500 

hydrolysis  of,  500 


1038 


INDEX 


Cellulose,  modification  of,  492 

mucilage  value  of,  541 

oxidation  products  of,  540 

preparation  of  pure,  492 
Cellulose  acetate,  506 

properties  of,  706 
Cellulose  acetate  silk,  705 
Cellulose  aceto-sulfates,  508 
Cellulose  benzoate,  506 
Cellulose  dinitrate,  526 
Cellulose  formate,  508 
Cellulose  from  cotton,  normal,  493 
Cellulose  hexanitrate,  526 
Cellulose  hydrate,  580,  637 
Cellulose  nitrates,  508 
Cellulose  pentanitrate,  526 
Cellulose  peroxide,  542 
Cellulose  solution,  uses  of,  721 
Cellulose  sulfate,  508 
Cellulose  tetracetate,  507 
Cellulose  tetranitrate,  526 
Cellulose  thiocarbonate,  505 
Cellulose  trinitrate,  526 
Cellulose  xanthate,  505 
Champa  silk,  316 
Chapped  silk,  281 
Chardonnet  silk,  675 
Chemical  wood  fiber,  855 
China  curlies  silk,  254 
China  grass,  776,  889 
China  silk,  252 
China  waste,  253 
Chinchilla  fur,  238 
Chinese  camel-hair,  228 
Chinese  cotton,  399 
Chinese  jute,  760 
Chinese  rice  paper,  861 
Chinese  wool,  54 
Chlorinated  wool,  159,  160 
Cholesterol,  122 
Chop  silk  brands,  254 
Chrome,  assistance  for  in  mordanting,  170 

use  of  in  mordanting,  169 
Chrysotile  asbestos,  25,  27 
Climate,  testing  effect  of  on  fabric,  993 
Clipped  wool,  65 
Clothing  wool,  65 
Cocoanut  fiber,  826 
Cocoons,  steaming  of,  260 
Cocuiza  fiber,  798 
Cohesion  test  for  raw  silk,  289 
Coir  fiber,  825,  894 


Collodion,  523 

Collodion,  silk,  675 

Colloidal  character  of  fibers,  6 

Colorado  hemp,  799 

Combed  cotton  yarn,  444 

Commercial  availability  of  fibers,  6 

Commercial  fibers,  864 

Compound  celluloses,  508 

Conditioning,  apparatus  for,  949 
calculations  involved  in,  951 

Conditioning  of  silk,  274 

Conditioning  of  textile  fabrics,  943 

Coney  fur,  238 

Coniferous  wood  fibers,  microscopy  of,  342 

Conversion  factors  in  numbering  yarns, 
1012 

Copper-ammonia  solution,  preparation  of, 
686 

Copper  number  of  cotton,  473 

Copper  values  of  various  fibers,  542 

Cordage,  testing  for  fibers  in,  929 

Cordage  fibers,  328,  864 

Cordage  fibers,  comparison  of  800,  815, 
818,  823,  827 
testing  of,  929 

Cordonnet  silk,  281 

Cordova  wool,  65 

Cork  tissue,  characteristics  of,  347 

Cortical  cells  in  wool  fiber,  93 

Cosmos  fiber,  197 

Cotswold  wool,  microscopy  of,  86 

Cotted  fleeces,  122 

Cotton,  absorption  of  acids  by,  148 
acidity  of,  537 
acetylation  of,  530 
action  of  acetic  acid  on,  527 
action  of  acid  salts  on,  544 
action  of  acids  on,  515 
action  of  alkali  and  air  on,  533 
action  of  alkali  and  heat  on,  534 
action  of  alkali  and  pressure  on,  535 
action  of  alkaline  salts  on,  546 
action  of  alkalies  on,  533 
action  of  ammonia  on,  535 
action  of  ammonium  persulfate  on, 

538 
action  of  barium  chlorate  on,  546 
action  of  basic  salts  on,  545 
action  of  caustic  potash  on,  536 
action  of  citric  acid  on,  528 
action  of  cuprammonium  solution  on, 
514 


INDEX 


1039 


Cotton,  action  of  dilute  acids  on,  520 
action  of  dyestuffs  on,  550 
action  of  Fehling's  solution  on,  541 
action  of  ferments  on,  553 
action  of  frost  on,  513 
action  of  fumaric  acid  on,  529 
action  of  gallic  acid  on,  532 
action  of  heat  on,  510 
action  of  hydrochloric  acid  on,  518 
action  of  hydrofluoric  acid  on,  527 
action  of  iron  mordants  on,  546 
action  of  Ught  on,  511 
action  of  magnesium  chloride  on,  544 
action  of  maleic  acid  on,  529 
action  of  metallic  salts  on,  543 
action  of  micro-organisms  on,  555 
action  of  mildew  on,  554 
action  of  milk  of  lime  on,  536 
action  of  neutral  salts  on,  545 
action  of  nitric  acid  on,  522 
action  of  organic  acids  on,  527 
action  of  oxalic  acid  on,  529 
action  of  oxidising  agents  on,  537 
action  of  phosphoric  acid  on,  516 
action  of  phospho-sulfuric   acid   on, 

516 
action  of  sea  water  on,  546 
action  of  sodium  sulfide  on,  537 
action  of  stannic  salts  on,  544 
action  of  steam  on,  512 
action  of  strong  alkali  on,  536 
action  of  sulfur  on,  537 
action  of  sulfuric  acid  on,  515 
action  of  tannin  on,  531 
action  of  tartaric  acid  on,  528 
action  of  tungstic  acid  on,  531 
action  of  ultra-violet  rays  on,  511 
action  of  water  on,  511 
action  of  zinc  chloride  on,  545 
adsorption  of  mordants  by,  543 
antiquity  of,  2 
ash  of,  483 
basicity  of,  537 

boiling  out  with  sodium  peroxide,  535 
botanical  classification  of,  375 
botany  of,  361 
color  of,  405 
coloring  matter  in,  479 
commercial  varieties  of,  385 
cross  fertilization  of,  385 
cultivation  of,  362 
determining  moisture  in,  464 


Cotton,  dry  distillation  of,  510 

dyed  with  sulfur  colors,  tendering  of, 
517 

extractive  constituents  of,  471 

first  use  of  in  Europe,  3 

giving  wool-like  chai'acter  to,  525 

grading  of,  399 

growth  of,  363 

habitat  of,  362 

history  of,  354 

hydrolysis  of  by  acids,  516 

hygroscopic  quality  of,  460 

impurities  in,  467 

influence  of  moisture  on  strength  of, 
448 

iron  in,  484 

mineral  matter  in,  482 

names  for  in  different  countries,  359 

nitrogen  in,  486 

nitrogenous  matter  in,  486 

official  grades  for,  400 

oil  in,  468 

pectin  compounds  in,  481 

phosphoi'ic  acid  in,  484 

proper  soil  for,  374 

reaction  when  burned,  510 

resist  dyeing  of,  530 

spinning  qualities  of,  443 

staple  of  commercial,  421 

use  of  sodium  perborate  on,  536 
Cotton  and  linen,  distinction  between,  920 
Cotton  as  a  paper  fiber,  856 
Cotton  ash,  analysis  of,  484 
Cotton  boiling,  removal  of  waxes  in,  473 
Cotton  bolls,  364 
Cotton  card,  444 
Cotton  comber,  445 
Cotton  fabrics,  lustering  of,  464 

effect  of  chemical  processes  on,  552 

transparent  finish  on,  605 
Cotton  fiber,  885 

action  of  Schweitzer's  reagent  on,  434 

anatomical  structure  of,  433 

comparison  of  different  varieties  of, 
425 

conditions  affecting  quality  of,  373 

development  of,  372 

dimensions  of,  414 

effect  of  caustic  soda  on,  607 

effect  of  industrial  processes  on,  448 

making  transparent,  525 

microchemical  reactions  of,  443 


1040 


INDEX 


Cotton  fiber,  microscopy  of,  339,  439 

physical  factors  for,  431 

physical  structure  of,  411 

physiology  of,  371 

rigidity  of,  432 

spiral  structure  in,  435 

structural  parts  of,  434 

thickness  of,  428 

twist  in,  439 

tensile  strength  of,  445 
Cotton  fiber  under  polarised  light,  412 
Cotton  gins,  366 

Cotton  grades,  comparative  values  of,  402 
Cotton  grading  in  Europe,  385 
Cotton  grass,  884 
Cotton  industry,  statistics  of,  410 
Cotton  linters,  370 
Cotton  plant,  classification  of,  384 

constituents  of,  368 
Cotton  spindles  of  world,  409 
Cotton  staple,  measurement  of,  416 
Cotton  statistics,  407 
Cotton  tree,  384,  665 
Cotton  yarn,  effect  of  bleacnmg  powder 
on,  540 

effect  of  drying  on,  510 

effect  of  moisture  on,  514 

count  of,  387,  1001 
Cotton  yarn,  nitration  of,  524 
Cotton-gum,  469 
Cotton-stone,  26 
Cotton-tail  rabbit  fur,  241 
Cotton-wax,  468 
Cottonised  flax,  753 
Cottonised  ramie,  779 
Cottonising  process  for  bast  fibers,  754 
Count  of  yarns,  998 
Couratari  fiber,  844 
Courtrai  flax,  737 

preparation  of,  744 
Cow-hair,  78,  230 

distinction  of  from  wool,  231 
Creeks  cotton,  394 
Creole  wool,  65 
Creping  cotton  cloth,  646 
Creping  of  silk,  304 
Creping  woolen  goods  with  thiocyanates, 

174 
Crepon  effects  on  union  goods,  155 
Crepon  effects  on  woolen  cloth,  175 
Crimps  in  wool  fiber,  95 
Crin  vegetal,  327,  842 


Crinol  fiber,  724 

Crocidolite,  26 

Cross-bred  wools,  60 

Cross-sections  in  fiber  microscopy,  20 

Cross-sections  of  fibers,  preparation  of,  84 

Crystal  finish  on  cotton  cloth,  644 

Cuban  hemp,  798 

Cuprammonium  silk,  685 

Cuprate  silk,  685 

manufacture  of,  690 

recovery  of  ammonia  in,  693 

recovery  of  copper  in,  693 
Cut  of  woolen  yarn,  1004 
Cutose,  348 

estimation  of,  769 
Cyprian  gold  thread,  12 
Cyprus  asbestos,  24 


D 


Damask  j^arn  silk,  255 
Date  palm  fiber,  840 
Dead  cotton,  412 
Decorticating  machine,  810,  835 
Deer,  beard  hair  of,  79 

fiber  of,  78 
Deer-hair,  234 
Degumming  raw  silk,  291 
Delaine  wool,  65 
Dellerite,  35 
Delta  cotton,  394 
Demi-luster  wools,  60 
Denier,  derivation  of,  1006 
De-wooling  skins,  lime  method  for,  64 

sulfide  method  for,  64 

sweating  process  for,  64 
Devil's  cotton,  799 
Diazotised  wool,  150 
Dicotyledonous  plants,  320 
Discharging  raw  silk,  291 
Dislocations  in  bast  fibers,  321 
Domestic  cat,  fiber  of,  78 
Duckbill  fur,  239 

Duplex  fabrics,  waterproofing  of,  565 
Durability  of  fabrics,  testing,  994 
Dutch  flax,  737 
Duvetyn  finish,  645 
Dyeing,  effect  of  on  woolen  fabrics,  117. 

178 
Dyeing  theory  for  cotton,  550 
Dyestuffs,  action  of  on  vool,  176 


INDEX 


1041 


E 

Eagle  silk,  695 

East  Indian  goat-hair,  228 

Echappe  silk,  281 

EdrMon  vegetale,  664 

Egyptian  cotton,  389 

Egyptian  flax,  753 

Egyptians,  flax  cultivation  by,  2 

Ejon  fiber,  840 

Elairerin,  123 

Electric  potential  of  textile  fibers,  177 

Electrolytic  waterproofing,  apparatus  for, 

567 
Embroidery  silk,  255,  281 
Emerising  cotton  fabrics,  645 
Endochrome  in  cotton  fiber,  373 
Epidermal  scales,  size  of,  90 
Eria  silk,  259,  316 
Erh-wan-shu  silk  waste,  260 
Ermine  fur,  235 
Esparto,  microscopy  of,  340 
Esparto  fiber,  335,  859,  891 
European  silk,  252 
Extract  wool,  111,  185,  186 


Fabric  fibers,  328 

Fabric-testing  machines,  453 

Fabrics,  microscopic  analysis  of,  996 

Fabrics  of  mixed  fibers,  analysis  of,  914 

Fade  marks  on  woolen  fabrics,  130 

Faded  wool,  130 

Fagara  silk,  259 

False  nettle  fiber,  778 

Fayal  lace,  823 

Fehling's  reagent,  preparation  of,  960 

Felting  action  of  wool,  91 

Fiber  cells,  dimensions  of,  323 

Fiber-testing  machines,  449 

Fibers,  elasticity  of,  5 

classification  of  by  origin,  7 

cohesiveness  of,  4 

number  of  different  kinds  of,  7 

pliability  of,  5 
Fibers  in  antiquity,  1 
Fibers  used  in  textiles,  properties  required 

of,  1 
Fibro  yarns,  724 
Fibroine,  291,  296 

chemical  properties  of,  298 
Fiji  sea-island  cotton,  388 


Fil  de  Florence,  248 
Filoselle  silk,  255 

Finishing    materials    in    fabrics,    estima- 
tion of,  978 
Finishing  operations  on  wool,  effect  of,  116 
Finishing  woolens,  loss  of  weight  during, 

117 
Fique  fiber,  798 

Fire-proofing,  effect  of  various  salts  in,  569 
Fire-proofing  compounds,  effectiveness  of. 
573 

preparation  of,  570 
Fire-proofing  fabrics,  apparatus  for,  576 
Fire-proofing  of  cotton  fabrics,  568 
Fireweed  fiber,  655 
Fish  wool,  317 
Fitch  fur,  235 
Flacherie,  257 

Flame-proofing  of  cotton  fabrics,  568 
Flannelette,  non-inflammable,  569 
Flax,  antiquity  of,  1 

history  of,  736 

impurities  in,  746 

microscopy  of,  339 

retting  of,  741 

waste  from,  747 
Flax  breaker,  742 
Flax  fiber,  action  of  steam  on,  753 
Flax  plant,  736 

analysis  of,  747 

diseases  of,  739 
Flax  trade,  statistics  of,  740 
Flax  wax,  755 
Fleece,  classification  of  fibers  in,  55 

grading  of,  57 
Fleece  wool,  63 
Flemish  flax,  737 
Flocks,  185,  196 
Florette  silk,  281 
Florida  sea-island  cotton,  387 
Floss  asbestos,  25 
Floss  silk,  252,  278 
French  flax,  738 
French  gray  waste,  254 
Frisonnets  silk,  252 
Frisons,  252 
Fruit  fibers,  320 

Fulling,  effect  of  on  woolen  fabrics,  118 
Furs,  alteration  products  of,  236 
Furs,  durability  of,  237 
Fur  fibers,  235 

pigmentation  in,  241 


1042 


INDEX 


G 

Gage  test  for  raw  milk,  285 

Galettame  silk,  252 

Galgal  filler,  665 

Gallini  cotton,  390 

Gambo  hemp,  802,  892 

Gamma-oxycellulose,  538 

Garnetted  waste,  198 

Garnetting,  183 

Gattine,  257 

Gauffer  finish  on  cotton  cloth,  644 

Gelatine  fibers,  15 

Gelatine  silk,  708 

Georgia  uplands  cotton,  377 

Giant  lily  fiber,  818 

Glanzstoff  silk,  686 

Glass  cotton,  11 

Glass  fibers,  11 

Glass  wool,  11, 

Glovers'  wool,  100 

Goat-hair,  217 

comparison  of  with  wool,  219 
Gorilla  yarn,  221 
Gossypium  arboreum,  383 
Gossypium  bardadense,  376 
Gossypium  herbaccum,  378 
Gossypium  hirsutum,  381 
Gossypium  religiosum,  383 
Grading  cotton,  399 

factors  determining,  403 
Grass  cloth,  780 
Grasserie,  257 
Gray  squirrel,  fiber  of,  78 
Grease,  determination  of  in  fabrics,  975 
Greasy  wool,  analysis  of,  122 
Green  cotton,  403 
Green  ramie,  777 
Grege  silk,  278 
Grist  of  yarns,  1001 
Ground  wood-pulp,  852 
Gru  gru  fiber,  838 
Guanaco,  227 

fiber  of,  78 
Guinea  pig  fur,  240 
Gulf  cotton,  393 
Gum  waste,  253 
Guncotton,  526 

H 

Hair  and  wool,  comparison  of,  38 
Hair  fibers,  336 


Hair  fibers,  comparative  strengths  of,  102 

comparison  of,  228 

manner  of  growth,  75 
Hair  follicle,  75 
Hair  seal  fur,  238 
Hairs,  classification  of,  38 
Half-bred  wools,  60 
Hall  finish,  640 
Hard  fibers,  328 

Hard  wood  fibers,  microscopy  of,  342 
Hare,  fiber  of,  78 
Hare  fur,  238 

Heat  conductivity  of  fibers,  9,  14,  35 
Heat-retaining  value  of  fabrics,  10,  994 
Heberlein's  finish  on  cotton,  649 
Hemp,  790,  890 

analysis  of,  797 

as  a  paper  fiber,  857 

common,  791 

distinction  of  from  flax,  796 

fimble,  791 

mercerising  of,  798 

microscopy  of,  339,  794 

preparation  of,  793 

testing  for,  925 

uses  of,  798 

use  of  by  ancients,  2 
Hemp  seed,  794 
Hemp  yarn,  count  of,  1019 
Henequen  fiber,  816 
Hinde  cotton,  390 
Hingunghat  cotton,  392 
History  of  fibers,  1 
Hog  wool,  63 
Hollow  textile  fibers,  673 
Honduras  fiber,  839 
Hop  fiber,  334,  861 
Hornblende  asbestos,  30 
Horse-hair,  78,  231 
Hosiery  yarn  silk,  255 
Huanaco,  227 
Hudson  seal  fur,  236 
Huller  gin,  366 

Humidity,  effect  of  on  fibers,  947 
Hungarian  hemp,  794 
Hydracellulose,  637 
Hydralcellulose,  502,  543 
Hydraulic  Schreiner  calender,  642 
Hydrocellulose,  499 

reactions  of,  501 
Hydrolysed  cotton,  reactions  of,  517 
Hydrolysis  of  vegetable  fibers,  352 


INDEX 


1043 


Iceland  wool,  48 

Ife  hemp,  833 

Imitation  horse-hair,  830 

Incas,  use  of  cotton  by,  2 

India,  fibers  of  ancient,  2 

Indian  cotton,  392 

Indian  gum  waste  silk,  254 

Indian  hemp,  798 

Indicators  for  acidity  in  cotton  cloth,  522 

lodine-sulfuric  acid  reagent,  reactions  of, 

903 
lonamine  dyes  for  acetate  silk,  711 
Irish  flax,  738 
Isocholesterol,  123 
Istle  fiber,  828 
Italian  asbestos,  24 
Italian  hemp,  792 
Iwashiro  noshi  waste  silk,  254 
Ixtle  fiber,  822 


Jager-cloth,  227 
Japanese  hemp,  792 
Japan  silk,  252 
Joanovich  cotton,  390 
Jute,  760,  891 

action  of  steam  on,  768 

analysis  of,  768 

microscopy  of,  339 

retting  of,  762 

statistics  of,  771 

testing  for,  925 

uses  of,  770 

varieties  of,  763 
Jute  as  a  paper  fiber,  859 
Jute  butts,  762,  770 
Jute  fiber,  chemical  properties  of,  766 

microscopy  of,  764 

preparation  of,  762 
Jute  yarn,  count  of,  1019 

K 

Kangaroo  fur,  240 

Kapa  cloth,  778,  842 

Kapok,  657 

buoyancy  of,  657 
detection  of  cotton  in,  932 
uses  for,  659 

Karadagh  wool,  51 

Kashmere  silk,  314 


Kempy  wool,  99 
Keratine,  126 
Khoi  wool,  51 
Kidney  cotton,  395 
Kier-boiling,  effect  of  air  in,  533 

loss  of  weight  in,  533 
Kikai  Kibbizzo  silk  waste,  254 
Kitool  fiber,  329,  840 
Kittul  fiber,  329,  841 
Knub  waste,  253 
Koala  fur,  239 
Kolinsky  fur,  235 
Kosmos  fiber,  771 
Krais  system  for  recovering  caustic  soda, 

629 
Kumbi  fiber,  665 


Lace  bark,  329 

Lace  yarn  silk,  255 

Lamb's  wool,  63,  88 

Lana  del  tambor,  655 

Lana  vegetale,  656 

Lano  di  Vetro,  11 

Lanuginic  acid,  128 

Leaf  fibers,  333 

Leaf-hairs,  320 

Lechuguilla  fiber,  822 

Lehner's  silk,  683 

Length  of  fibers,  economic  limit  of,  4 

Licella  yarn,  846 

Lignification,  chemical  constant  of,  776 

Lignification  of  fibers,  testing  for,  350 

Ligniform  asbestos,  27 

Lignin,  349 

testing  for,  931 
Lignocellulose,  508,  773 
Lignone,  estimation  of,  774 
Lincoln  wool,  microscopy  of,  87 
Linden  bast  fiber,  332 
Linen,  testing  for,  925 
Linen  and  hemp,  distinction  between,  925 
Linen  as  a  paper  fiber,  857 
Linen  fiber,  888 

chemical  composition  of,  755 

chemical  properties  of,  751 

microscopy  of,  748 

physical  properties  of,  751 

preparation  of,  739 

regain  in,  756 
Linen  yarn,  749 

count  of,  757,  1018 


1044 


INDEX 


Linen  yarn,  affect  of  moisture  on,  514 

properties  of,  757 
Lint  fibers,  328 
Linter  gin,  368 
Linters,  358 
Llama,  220,  225 
Llama  fiber,  225 
London  shrunk  fabrics,  143 
Lousiness  in  silk  fiber,  294 
Lowe's  silk,  709 
Lumen  of  cotton  fiber,  413 
Lumen  in  fibers,  321 
Luster  of  fibers,  6 
Luster  wools,  60 
Lustering  cotton  cloth,  640 
Lustra-cellulose,  673 
Lyon's  gold  thread,  12 

M 

Maceo  cotton,  398 

Machines  for  testing  strength  of  fibers, 

449 
Madar  floss,  670 
Maguey  fiber,  819 
Majagua  fiber,  803 
Mahno  fiber,  819 
Malt  extracts,  use  o£,  553 
Man,  hair  of,  78 
Manila  hemp,  809,  893 
analysis  of,  813 
distinction  of  from  sisal,  813 
microscopy  of,  340 
statistics  of,  812 
stegmata  in,  812 

hemp  and  sisal,  distinction  between, 
929 
Marabout  silk,  281 
Maranhams  cotton,  397 
Marine  fiber,  807 
Marmoset  fur,  140,  238 
Marsdenia  fiber,  670 
Marten  fur,  235 
Matamoros  hemp,  822 
Matter  system  for  recovering  caustic  soda, 

626 
Matting  fibers,  330,  864 
Mauritius  hemp,  819 
Mechanical  wood  fiber,  852 
Median  layer  in  vegetable  fibers,  337 
Medium  wool,  65 
Medullary  cells  of  wool,  79,  96 


Mercerisation,     determining    degree    of, 

601,  632 
Mercerised  cotton,  absorption  of  dyes  by, 
600 

absorption  of  metallic  oxides  by,  630 

affinity  of  dyes  for,  630 

cause  of  luster  in,  590 

chemical  activity  of,  630 

copper  number  of,  639 

dyeing  properties  of,  632 

hygroscopic  properties  of,  635 

microscopy  of,  588,  639 

proper  twist  for,  618 

properties  of,  589 

scrooping  of,  613 

structure  of,  589 

tests  for,  633 

ultramicroscopic  appearance  of,  636 
Mercerised  wool,  154 
Mercerised  yarn,   lustering  machine  for, 

604 
Mercerising,  536 

absorption  of  caustic  soda  in,  584 

action  of  sodium  chloride  in,  599 

chemicals  used  in,  597 

conditions  for,  596 

contractive  force  in,  611 

crepe  effects  in,  646 

discussion  of  patents  on,  580 

effect  of  on  yarns,  594 

effect  of  temperature  on,  602 

effect  of  tension  in,  593 

effect  of  time  on,  606 

Mercer's  patent  for,  578 

methods  of,  618 

physical  changes  in,  586 

quality  of  fiber  for,  615 

recovery  of  caustic  soda  in,  625 

stretching  force  in,  608 

theory  of,  595 

use  of  tension  in,  607 

washing  process  in,  611 
Mercerising  cotton  cloth,  623 
Mercerising  cotton  skeins,  618 
Mercerising  cotton  sliver,  619 
Mercerising  factor  for  vegetable  fibers,  353 
Mercerising  in  pattern  effect,  602 
Mercerising  loose  cotton,  619 
Mercerising     machine     for     light-weight 

cloth,  617 
Mercerising  machines,  583 
Mercerising  padder  for  piece  goods,  610 


INDEX 


1045 


Mercerising  range  for  cloth,  620 
Mercerising  with  acid,  647 
Mercerising  with  nitro-sulfuric  acid,  653 
Mercerising  with  sulfuric  acid,  605 
Merino  sheep,  European,  46 

origin  of,  47 
Merino  wool,  microscopy  of,  85 

qualities  of,  60 
Mesopotamian  wool,  51 
Meta-pectic  acid,  482 
Metacellulose,  estimation  of,  769 
Metal  yarns,  12 
Metallising  yarns,  12 
Meteor  fiber,  724 

Methyl  value  of  vegetable  fibers,  351 
Mexican  fiber,  839 
Micrometer  ocular  for  fiber  measurement, 

20 
Micron,  definition  of,  24 
Microphotographs,  preparation  of,  16 
Microscope  for  fiber  work,  16 
Microscopy  of  fibers,  15 
Microtome  for  cutting  fibers,  20 
Mildew  in  wool,  182 

Mildew  resistence,  testing  canvas  for,  557 
Mildew-proofing  of  cotton  goods,  556 
Millon's  reagent,  298 
Milkweed  fiber,  655,  666 
Mineral  fibers,  10 
Mineral  wool,  13 
Mink  fur,  236 
Minor  hair  fibers,  209 
Mitafifi  cotton,  389 
Mixed  fibers,  analysis  of,  897 
Mobile  cotton,  395 
Mohair,  209 

classification  of,  211 

comparison  of  with  wool,  210 

domestic,  210 

grading  of,  226 

microscopy  of,  215 

from  Turkey,  211 

Mohair  noil,  107,  215 
Mohair  tops,  214 
Moire  antique  finish,  275 
Moire  finish  on  silk,  274 
Moire  ronde  finish,  275 
Moisture,   determination  of  in  vegetable 

fibers,  352 
Moisture  in  vegetable  fibers,  344 
Moisture  in  woolen  yarns,  variations  in, 
135 


Mole  fur,  239 

Momme  weight  of  silk,  267 

Monkey  grass,  840 

Monocotyledonous  plants,  320 

Montevidean  wool,  49 

Moonga  silk,  316 

Moorva  hemp,  833 

Mordanting,  effect  of  on  woolen  fabrics, 

178 
Mordants,  168 
Mordants  on  cotton,  544 
Mordants  on  wool,  comparison  of  various, 

171 
Motes  in  cotton,  405 
Mountain  cork,  27 
Mountain  flax,  27 
Mountain  leather,  27 
Mountain  sheep,  41 
Mountain  wools,  60 
Mounting  fibers  for  microscope,  18 
Mu,  a  microscopic  measurement,  24 
Mucuja  fiber,  838 
Mufflon  sheep,  41 
Muga  silk,  316 
Mummy  cloth,  2 
Mungo,  111,  184,  185,  186 
Muscardine,  257 
Muskmallow  fiber,  892 
Muskrat  fur,  239 
M.  V.  wools,  49 
Myhtta  silk,  258 

N 
Nankin  buttons,  253 
Nankin  cotton,  379,  399 
Neps  in  cotton,  405 
Neps  in  cotton  fabrics,  413 
Neri  silk,  252 
Nesselgarn,  831 
Nesseltuch,  831 
Nett  silk,  253 
Netting  fibers,  328 
Nettle  fiber,  830 
New  Zealand  flax,  803,  892 

microscopy  of,  341 

testing  for,  925 
Nitrated  cotton,  524 

Nitration  factor  for  vegetable  fibers,  353 
Nitrogen  in  cotton,  removal  of  by  bleach- 
ing, 488 
Noils,  107,  185,  197 
Non-flam  process  for  fire-proofing,  569 


1046 


INDEX 


Normal  cellulose,  467 
Noshito  Joshim  waste  silk,  254 
Nutria  fur,  238 

O 

Oil,  determination  of  in  fabrics,  975 

Okra  fiber,  803 

Opaline  effects  on  cotton  fabric,  546 

Opossum  fur,  239 

Organzine  silk,  279 

Oriental  rugs,  making  antique,  165 

washing  of,  165 
Orleans  cotton,  393 
Orsey  silk,  280 
Otter  fur,  236 
Ouate  vegetale,  664 
Ovis  ammon,  41 
Ovis  aries,  41 
Ovis  musmon,  41 
Oxy cellulose,  523 
Oxycellulose,  action  of  caustic  soda  on,53S 

formation  of  in  textile  processes,  538 

osazones  of,  540 

preparation  of,  539 

reactions  of,  539 

test  for,  541 
Oxycellulose    and    hydrocellulose,    differ- 
ence between,  542 
Oxycellulose  in  bleached  cotton,  detection 
of,  982 


Packing  fibers,  331 

Paco-vicuna,  224 

Paina  limpa,  656 

Paisley  shawls,  216 

Palmetto  fiber,  840 

Panama  hat  fiber,  330 

Pangane  hemp,  833 

Paper  fibers,  examination  of,  850 

Paper  mulberry  fiber,  842,  860 

Paper  yarn,  845 

dyeing  of,  849 

manufacture  of,  848 

uses  of,  850 

use  of  during  war,  3 
Papyrifera  fiber,  331 
Papyrus,  862 

Paracellulose,  estimation  of,  769 
Paraffin  duck,  564 
Paragrass,  840 
Parchment  finish  on  cotton,  651 


Parenchyma,  9 
Parisian  artificial  silk,  686 
Pat  silk,  316 
Pattes  de  lievre,  664 
Pauly  silk,  686 
Peat  fiber,  197,  844 
Pebrine,  256 
Pectic  acid,  482 

estimation  of,  769 
Pectin  in  cotton,  481 
Pectin  in  flax,  746 
Pectocellulose,  508 
Pectose,  746 
Peeler  cotton,  381,  393 
Perces  silk,  252 
Perigon  hair,  884 
Perini  fiber,  843 

Permanent  finish  on  cotton,  605,  652 
Permeability  of  fabrics,  testing  of,  994 
Pernambuco  cotton,  397 
Pernyi  silk,  258 
Persian  wool,  51 
Peruvian  cotton,  395 
Peruvian  cotton  in  wool  blends,  111 
Peruvian  sea-island  cotton,  388 
Photomicrographic  outfit,  21 
Piassave  fiber,  333,  840 
Picamer,  525 
PicroHte,  27 
Pierre  a  coton,  26 
Pigment  in  cotton  fibers,  481 
Pima  cotton,  377 
Pina  cloth,  824 
Pineapple  fiber,  823,  891 

microscopy  of,  341 
Pinna  silk,  316 
Piques  silk,  252 
Pita  de  corojo,  838 
Pita  fiber,  821 

microscopy  of,  340 
Pita  hemp,  893 
Plaiting  fibers,  330 
Plastic  effects  on  cotton  fabrics,  546 
Platanilo  fiber,  655 
Plumose  fibers,  335 
Plush  silk,  255 
Poll  silk,  281 
Polar  bear  fur,  239 
Polariscope  in  fiber  microscopy,  19 
Polarised  light,  examination  of  vegetable 

fibers  in,  338 
Poplar  cotton,  886 


INDEX 


1047 


Torosity  of  fibers,  6 

Posidonia  fiber,  807 

Potash  salts  in  wool  suint,  124 

Potting,  effect  of  on  woolen  fabrics,  119 

Prairie  dog  fur,  241 

Printing  with  bakelite,  13 

Projection  apparatus  in  fiber  microscopy, 

19 
Protectol,  155 
Protein  matter,  8 
Pseudo-fibers,  326 
Pseudo-jute,  892 
Pulu  fiber,  665 
Pulled  wool,  65,  88,  100 
Pulled  yarn  waste,  198 
Punjum  waste  silk,  254 
Pure  gold  thread,  12 
Pyroxylin,  523 
Pyroxylin  silk,  676 

bleaching  of,  681 

denitration  of,  682 

manufacture  of,  677 

use  of  calcium  chloride  for,  680 


Quill-hair,  40 


Q 


R 


Rabbit  fur,  238 

Rabbit-hair,  232 

Raccoon  fur,  236 

Racini  silk,  258 

Radium  finish,  641 

Radium,  treatment  of  textile  fabrics  with, 

175 
Raffia,  837 
Raffia  straw,  840 
Ramie,  776,  889 

antiquity  of,  3 

commercial  aspects  of,  789 

decortication  of,  782 

preparation  of,  780 

statistics  of,  789 
Ramie  fiber,  microscopy  of,  340,  786 

properties  of,  779 

uses  of,  785 
Ramie  yarn,  count  of,  1019 
Raphia,  837 
Raw  cotton,  benzene  extract  of,  471 

chemical  analysis  of,  475 

constituents  of,  467 


Raw  silk,  classification  of,  252 

production  of,  265 

tests  for  classification  of,  281 
Raw  wool,  composition  of,  121 
Reagents  for  testing  fibers,  866 
Reclaimed  wools,  classes  of,  184 
Recovered  wool,  183 

classification  of,  184 
Red  fox  fur,  235 
Red  Peruvian  cotton,  382 
Red  silk  cotton,  656 
Reed-mace  hair,  884 
Regain  in  conditioning,  943 
Regain  in  cotton,  461 
Regain  in  wool,  133 
Regain  in  silk,  274 
Regenerated  cellulose,  506 
Resist  dyeing  of  cotton,  531,  551 
Resist  process  in  wool  dyeing,  152 
Retting,  chemical  methods  of,  743 
Retting  flax,  741 
Retting  with  ferments,  743 
Rhea  fiber,  776 
Ribbon  bast,  329 
Rice  paper,  861 
Ricotti  silk,  252 
Rigging  the  fleece,  59 
Rinsing   machine   for    carbonised    wool, 

190 
Rippling  flax,  741 
Rivers  cotton,  394 
Roa  fiber,  889 
Roller  gin,  367 

Rope  fibers,  comparative  strength  of,  799 
Ropes,  shortening  of  in  water,  346 
Rosin  in  waterproofing  fabrics,  564 
Rough  Peruvian  cotton,  395 
Rubber  latex  for  waterproofing,  568 
Rugginose  silk,  252 
Run  of  woolen  yarn,  1004 
Russian  camel-hair,  228 
Russian  flax,  737 
Russian  hemp,  794 
Russian  sable  fur,  236 
Ruthenium  red  for  testing  fibers,  873 


S 


Sago  palm  fiber,  841 
Sakellarides  cotton,  390 
Sakiz  wool,  51 
Salamander  wool,  33 


1048 


INDEX 


Salmas  wool,  51 

Sampling  cotton  for  grading,  406 

Sampling  cotton  for  staple,  418 

Sana  fiber  in  Sanskrit,  2 

Sansevieria  fiber,  833,  893 

Schreiner  finish,  640 

Sclerenchymous  fibers,  337 

Scoured  wool,  64 

Scouring  loss  of  fabrics,  975 

Scroop  on  mercerised  cotton,  613 

Scroop  on  silk,  277 

Sea  otter  fur,  236 

Sea-island  cotton,  276,  386 

Sea-silk,  316 

Seaweed  fiber,  837 

Seed  grass,  fiber  from,  836 

Seed-hairs,  320 

Seed-hairs,  physical  structure  of,  335 

Seem  cohesion  machine,  289 

Sericine,  291 

composition  of,  300 
Sericose,  708 

Serigraph  test  for  raw  silk,  288 
Serimeter  test  for  raw  silk,  287 
Serine,  301 
Sewellel  fur,  240 
Sewing  silk,  255,  281 

numbering  of,  1013 
Shanghai  waste,  253 
Sheep,  classification  of,  41 

domestic,  43 

genealogy  of,  44 

geographical  distribution  of,  45 

introduction  of  into  America,  45 

Marco  Polo's,  40 

Spanish  merino,  45 

table  of  varieties  of,  52 

trade  classification  of,  44 
Sheep  dips,  114 
Sheep  of  United  States,  48 
Shoddy,  111,  183,  185 

detection  of,  200 

economic  aspect  of,  198 

examination  of,  199 

factors  in  determining,  200 

from  various  fabrics,  appearance  of, 
204 

microscopic  appearance  of,  199 

microscopy  of,  203 

preparation  of  from  rags,  186 
Siam  fiber,  840 
Silicate  cotton,  13 


Silk,  absorption  of  acids  by,  146 
action  of  acids  on,  303 
action  of  alkalies  on,  305 
action  of  chlorine  on,  308 
action  of  dyestuffs  on,  308 
action  of  formic  acid  on,  305 
action  of  heat  on,  302 
action  of  hydrochloric  acid  on,  147, 

304 
action  of  hydrofluoric  acid  on,  304 
action  of  hydrofluosilicic  acid  on,  304 
action  of  metallic  salts  on,  306 
action  of  nitric  acid  on,  304 
action  of  polarised  light  on,  302 
action   of   Schweitzer's    reagent    on, 

308 
action  of  sodium  chloride  on,  307 
action  of  stannic  chloride  on,  308 
action  of  sugar  on,  308 
action  of  sulfuric  acid  on,  304 
action  of  tannic  acid  on,  303 
action  of  water  on,  302 
action  of  zinc  chloride  on,  307 
analysis  of  weighting  in,  960 
cause  of  tender  spots  on,  306 
introduction  of  into  Europe,  3 
methods  of  weighting,  309 
microscopical  characteristics  of,  942 
polariscopic  examination  of,  941 

Silk  and  cotton  fabrics,  analysis  of,  913 

Silk  and  wild  silks,  distinction  between, 
937 

Silk  chrysalis,  245 

Silk  cocoon,  248 

Silk  culture,  history  of,  242 

Silk  culture  in  America,  243 

Silk  fiber,  chemical  constitution  of,  291 
coloring  matter  in,  302 
density  of,  276 
diazotising  of,  298 
different  varieties  of,  251 
elasticity  of,  276 
electrical  properties  of,  274 
hygroscopic  nature  of,  273 
lustering  of,  274 
microchemical  reactions  of,  270 
microscopy  of,  270 
mineral  matter  in,  295 
origin  of,  242 
physical  properties  of,  273 
size  of  filaments  in,  249 
tensile  strength  of,  276 


INDEX 


1049 


Silk  filament,  size  of,  250 

Silk  glue,  291 

Silk  grass,  823,  839 

Silk  industry,  division  of,  242 

products  of,  264 
Silk  manufacturing  industry,   extent  of, 

263 
Silk  noil,  111,  255 
Silk  reeling,  277 
Silk  shoddy,  255 
Silk  statistics,  263 
Silk  throwing,  280 
Silk  wadding,  281 
Silk  waste,  blending  of,  255 
Silk  weighting,  calculations  in,  971 

prevention  of  deterioration  in,  306 
Silk  yarns,  classification  of,  280 

count  of,  1006 
Silk-cotton  plant,  385 
Silk-moth,  245,  251 
Silk-moth  eggs,  245 
Silvalin  yarn,  846 
Silkweed  fiber,  666 
Silkworm,  244 

cultivation  of,  245 

diseases  of,  256 

life  history  of,  246 

silk-producing  glands  of,  246 

spinneret  of,  247 

gut,  248 
Simal  cotton,  656 
Sinew  fiber,  318 
Sisal  hemp,  816 

microscopy  of,  341 
Size  of  yarns,  determination  of,  998 
Sizing  test  for  raw  silk,  284 
Skein  mercerising,  machine  for,  591 
Skin  wool,  64,  101 
Skunk  fur,  238 
Slag  wool,  13 
Sledge  pattern  sorter,  418 
SHpe  wool,  64,  101 
Smooth  Peruvian  cotton,  397 
Smyrna  cotton,  391 
Soda  pulp,  855 
Soft  fibers,  328 
Sole  de  France,  684 
Sole  ondee,  281 
Solidonia  fiber,  836 
Soujbulak  wool,  51 
Soyan  cloth,  259 
Spanish  moss,  834 


Specific  heat  of  fibers,  9 
Spider  silk,  262 
Spinning  fibers,  328 

Spontaneous  combustion  of  fabrics,  test- 
ing for,  992 
Spun  glass,  11 
Spun  silk,  278 

count  of,  1012 
Squirrel  fur,  238 
Squirrel  monkey  fur,  239 
Staff,  331 

Stain  remover  for  cotton  fabrics,  257 
Staple  fiber,  724 

Staple  fiber  fabrics,  analysis  of,  911 
Staple  of  fiber,  fineness  of,  5 
Statistics  of  fiber  industries,  23 
Steam  shrunk  fabrics,  143 
Steam  waste  silk,  254 
Stearerin,  123 
Stegmata,  348 
Steinflachs,  26 
Stem  fibers,  320 
Sthenosage    process     for    artificial    silk, 

702 
Stinging  nettle,  fiber  of,  830 
Stone-flax,  26 
Straw,  microscopy  of,  340 
Straw  fibers,  858 
Straw  plaits,  330 
Stringy  cotton,  405 
Stripping  raw  silk,  291 
Strophanthus  fiber,  886 
Structural  fibers,  326,  864 
Stuffing  fibers,  331 
Stycos  fiber,  780 
Sugar-cane  hair,  886 
Suint,  123 

analysis  of,  123 

potash  salts  in,  124 
Sulfur  in  wool,  determination  of,  132 

effect  of  in  dyeing,  130 
Sulfur  stains  on  woolen  goods,  130 
Sultain  cotton,  391 
Sunn  hemp,  798,  890 

analysis  of,  801 

distinction  of  from  hemp,  801 
Surat  cotton,  393 
Surface  fibers,  326,  864 
Sulfate  pulp,  855 
Sulfite  pulp,  855 

Swiss  finish  on  cotton  fabrics,  526,  64" 
Swiss  Lake  dwellers,  use  of  flax  by,  1 


1050 


INDEX 


Tables  for  yarn  count,  1015 

Taliiti  cotton,  383 

Tahiti  sea-island  cotton,  388 

Talipot  fiber,  840 

Tampico  hemp,  822 

Tanners'  wool,  100 

Tannic  acid,  action  of  on  cotton,  532 

Tannin,  absorption  of  by  cotton,  531 

Tapa  cloth,  842 

Tarmate  silk,  252 

Tar  on  wool,  121 

Tassel  silk,  255 

Ta-wan-shu  silk  waste,  260 

Tecuma  palm  fiber,  841 

Teg  wool,  63 

Templite  asbestos,  24 

Tendering  of  cotton  with  sulfur  colors,  517 

Tensile  strength  of  fibers,  4 

Territory  wool,  65 

Texas  cotton,  394 

Textile  fabrics,  analysis  of,  905 

Textile  fibers,  action  of  iron  salts  on,  169 
antiquity  of,  3 
chemical  reactions  of,  867 
copper  values  of,  541 
general  analysis  of,  864 
hygroscopic  moisture  in,  138 
microchemical  test  of,  866 
microscopical  investigation  of,  865 
properties  required  in,  3 

Textile  paper  fibers,  331 

Textilose,  846 

Thibet  cashmere,  228 

Thibet  sheep,  54 

Thibet  wool,  197 

Thiele's  silk,  691 

Thrown  silk,  count  of,  1013 

Tillandsia  fiber,  834 

Tin  weighting  of  silk,  312 

Titer  of  sOk  yarns,  1006 

Tops,  107 

range  of  qualities  of,  110 
testing  of,  108 

Tow  yarn,  749 

Tram  silk,  279 

Transparent  finish  on  cotton,  652 

Tree-basts,  329 

Tree  cotton,  381 

Truth-in-fabric  legislation,  63 

Tsatlees,  267 


Tubize  silk,  686 

Tucum  thread,  841 

Tungstic  acid,  action  of  on  wool,  173 

Turkey  mohair,  211 

qualities  of,  212 
Tussah  silk,  259 

classification  of,  261 

properties  of,  313 

uses  for,  262 
Tussah  wast«  silk,  255,  261 
Tussur  silk,  313 

U 

Ultramicroscope,  721 
Unbari  cotton,  390 
Uniformity  of  staple,  5 
Unripe  cotton  fibers,  411 
Unshrinkable  woolen  fabrics,  161 
Upholstery  fibers,  864 
Upland  cotton,  381,  395 
Urena  sinuata,  fiber  of,  833 
Uruguayan  wool,  49 
Urumiah  wool,  51 


Van  mohair,  212 

Vanadium,  action  of  on  cellulose,  508 

Vanduara  silk,  709 

Vascular  fibers,  320 

Vasculose,  estimation  of,  769 

Vegetable  down,  655,  664,  886 

Vegetable  fibers,  action  of  water  on,  346 
albuminous  matter  in,  348 
analytical  reactions  of,  880 
botanical  classification  of,  332 
chemical  investigation  of,  351 
classification  of,  326 
color  of,  343 

development  of  fibers  in,  323 
economic  classification  of,  328 
effect  of  moisture  on,  344 
elasticity  of,  343 
general  structure  of,  8 
general  tests  for,  875 
hygroscopic  properties  of,  344 
luster  of,  343 

micro-analytical  tables  for,  883 
micro-chemical  tests  for,  349 
microscopy  of,  338 
origin  of,  319 
physical  properties  of,  343 
resistance  of  to  moisture,  671 


INDEX 


1051 


Vegetable  fibers,  silicious  matter  in,  348 

tensile  strength  of,  344 
Vegetable  fibers  in  polarised  light,  338 
Vegetable  hairs,  332 
Vegetable  horsehair,  834 
Vegetable  parchment,  515 
Vegetable  sUk,  665,  883 

spinning  of,  668 
Vegetable  wool,  671,  841 
Vicogne  fiber,  221 
Vicogne  yarn,  224 
Vienna,  fiber  of,  78 
Vicuna  goat,  220 
Vicuna  wool,  223 
Vine  cotton,  381 
Virgin  wool  controversy,  196 
Virgin  wool,  meaning  of,  63 
Viscelline  yarn,  703 
Viscolith,  702 
Viscose,  505,  537 

analysis  of,  700 

manufacture  of,  703 
Viscose  silk,  696 

manufacture  of,  697 

du  Vivier's  silk,  684 
Vulcanised  fiber,  503 

W 

Wadding  silk,  252 

Warp  mercerising  machine,  608 

Washed  wool,  64 

Waste  in  cotton  spinning,  407 

Waste  silk,  varieties  of,  252 

Water,  forms  of  combination  of  in  vege- 
table fibers,  352 

Watered  finish  on  silk,  274 

Waterproof  fabrics,  testing  of,  986 

Waterproofing,  use  of  aluminium  acetate 
for,  560 
use  of  casein  for,  561 
use  of  fats  and  waxes  for,  561 
use  of  gelatine  for,  561 
use  of  metallic  soaps  for,  563 
use  of  paraffin  for,  563 

Waterproofing   by  cuprammonium  proc- 
ess, 565 

Waterproofing  canvas,  563 

Waterproofing  fabrics,  559 

electrolytic  method  for,  566 

Waterproofing  fabrics  with  cellulose  ace- 
tate, 566 


Waterproofing   fabrics   with   drying   oils, 

566 
Waterproofing  fabrics  with  pyroxylin,  566 
Waterproofing  with  rubber  latex,  568 
Waterproofing  woolen  cloth,  166 
Watt  silk,  252 

Wearing  qualities  of  fibers,  6 
Weasel  fur,  240 

Weaving,  historical  development  of,  3 
Weft  silk,  280 
Weighted  silk,  analysis  of,  960 

preservation  of,  306 

properties  of,  310 
Weighting  of  cotton  yarns,  548 
Weighting  of  silk,  308 
Weighting   of  silk   and   boil-off,    relation 

between,  294 
Weighting  of  woolen  fabrics,  173 
West  Indian  cotton,  398 
Wether  wool,  63 
Wetting  property  of  cotton,  470 
Wetting-out  of  cotton,  470 
White  ramie,  777 
Wild  kapok,  656 
Wild  pineapple  fiber,  839 
Wild  silk,  257,  940 

comparison  of,  315 

microscopy  of,  272 
Wild  silk  cocoons,  treatment  of,  261 
Willesden  canvas,  514 
Willesden  finish,  565 
Williams  finish,  640 
Winding  test  for  raw  sUk,  282 
Wolverine  fur,  238 
Wood  tissue,  cells  of,  8 
Wood  wool,  187 
Woodchuck  fur,  238 
Wood-pulp  yarns,  845 
Woody  fiber  in  vegetable  fibers,  348 
Woody  fibers,  326 

microchemical  reactions  for,  348 
Woody  tissue,  characteristics  of,  347 
Wool,  action  of  acids  on,  146 

action  of  dry  heat  on,  139 

action  of  heat  on,  139 

action  of  moist  heat  on,  139 

action  of  steam  on,  139 

action  of  water  on,  139 

African  varieties,  50 

arsenic  in,  125 

Asiatic  varieties,  50 

Australian,  46 


1052 


INDEX 


Wool,  browning  of,  129 

character  of  English,  48 

commercial  grades  of,  65 

conditions  affecting  quahty  of,  112 

effect  of  cUmate  on,  43 

effect  of  cultivation  on,  43 

effect  of  heating  under  pressure,  140 

effect  of  pasturage  on,  43 

effect  of  soil  on,  43 

estimating  degree  of  hydrolysis  of,  140 

felting  of,  143 

hydrolysis  of,  140 

lustering  of,  165 

New  Zealand,  46 

Russian  varieties  of,  48 

South  American  varieties,  49 

standards  of  quality  of,  59 

sterilizing  for  anthrax,  221 

world  production  of,  71 
Wool  and  cotton  fabrics,  analysis  of,  905 
Wool  and  silk  fabrics,  analysis  of,  912 
Wool  blending,  methods  for,  111 

use  of  cotton  in,  111 
Wool  blends,  method  of  mixing,  112 
Wool  combing  machine,  106 
Wool  fabrics,  effect  of  overheating,  117 

weathering  of,  159 
Wool  fiber,  abnormal  growth  in,  86,  113 

absorption  of  acid  by,  146 

acid  nature  of,  143 

action  of  acetic  anhydride  on,  177 

action  of  acetyl  chloride  on,  177 

action  of  acid  salts  on,  168 

action  of  alkalies,  145 

action  of  alkalies  on,  153 

action  of  ammonia  on,  157 

action  of  ammonium  carbonate  on, 
157 

action  of  barium  hydroxide  on,  127, 
157 

action  of  borax  on,  157 

action  of  bromine  on,  160 

action  of  caustic  soda  on,  156 

action  of  chlorine  on,  159 

action  of  chromic  acid  on,  148 

action  of  concentrated  mineral  acid 
on,  151 

action  of  dilute  acids  on,  146 

action  of  dilute  sulfuric  acid  on,  146 

action  of  dyestuffs  on,  176 

action  of  formaldehyde  on,  166 

action  of  glaubersalt  on,  168 


Wool  fiber,  action   of   hydrochloric   acid 

on,  147 
action  of  hydrogen  peroxide  on,  158 
action  of  magnesium  chloride  on,  174 
action  of  metallic  salts  on,  168 
action  of  milk  of  lime  on,  157 
action  of  nitric  acid  on,  148 
action  of  nitrous  acid  on,  149 
action  of  organic  acids  on,  151 
action  of  oxidising  agents  on,  158 
action  of  potassium  bichromate  on, 

169 
action  of  potassium  carbonate  on,  158 
action    of    potassium    permanganate 

on,  159 
action  of  reducing  agents  on,  158 
action  of  sodium  bichromate  on,  169 
action  of  sodium  bisulfite  on,  158 
action  of  sodium  peroxide  on,  156,  158 
action  of  sodium  phosphate  on,  158 
action  of  strong  caustic  soda  on,  153 
action  of  sodium  tungstate  on,  173 
action  of  tannic  acid  on,  151 
action  of  thiocyanates  on,  174 
action  of  tungstic  acid  on,  173 
action  of  various  acids  on,  150 
action  of  zinc  sulfate  on,  175 
ash  of,  124 
basic  nature  of,  143 
chemical  constitution  of,  126 
coefficient  of  acidity  of,  144 
coloring  matter  in,  97,  125 
constituent  cells  of,  94 
cortical  layer  in,  81 
cross-section  of,  77 
cuticle  of,  80 
dry  distillation  of,  128 
effect  of  formaldehyde  on,  157 
effect  of  mildew  on,  182 
effect  of  moisture  on  properties  of,  134 
elasticity  of,  102 
epidermal  scales  of,  89 
felting  action  of,  91 
fineness  of  staple  of,  106 
general  properties  of,  39 
hygroscopic  quality  of,  132 
influence  of  manufacture  on,  115 
kemps  in,  100 
length  of,  106 

microchemical  reactions  of,  89 
microscopic  appearance  of,  77 
microscopy  of,  81 


INDEX 


1053 


Wool  fiber,  moduli  of  elasticity  of,  104 

moisture  in,  132 

morphology  of,  76 

nitrogen  in,  128 

number  of  scales  on,  90 

physical  properties  of,  101 

physiology  of,  75 

pigment  canal  in,  99 

protecting  of  from  alkalies,  155 

relation  between  diameter  and  curl, 
94 

strength  of,  102 

structure  of  scales  on,  83 

sulfur  in,  130 

thermo-chemical  reactions  of,  145 

treating  of  with  caustic  alkalies,  157 

unhealthy,  114 

variations  in,  91 

variations  in  diameter  of,  101 

water  of  hydration  in,  133 

waviness  of,  93 

yield  of  from  different  sheep,  122 
Wool  flocks,  196 
Wool  grease,  122 
Wool  gelatine,  140 
Wool  printing,  caustic  soda  treatment  in, 

155 
Wool  production,  statistics  of,  65 
Wool  production  in  United  States,  69 
Wool  shipments,  effect  of  humidity  on,  132 
Wool  structure,  varieties  in,  56 
Wool  substitute,  183,  780 
Wool  terms,  definitions  of,  61 
Wool-bearing  animals,  40 
Wool-fat,  76 

function  of,  76 
Wool-hair,  40 

Wool-like  finish  on  cotton,  653 
Wool-oil,  76 

Wool-sorter's  disease,  221 
Wool-sorting,  56 

Bradford  method  of,  60 


Wool-sorting,  diagram  of,  61 

Scotch  method  of,  61 
Woolen  and  worsted,  distinction  between, 

107 
Woolen  cloth,  effect  of  boiling  water  on, 
142 
effect  of  steaming  on,  141 
Woolen  fabrics,  action  of  atmosphere  on, 
159 
effect  of  mordanting  and  dyeing  on, 

178 
influence  of  weighting  on,  174 
making  unshrinkable,  161 
shrinking  of,  143 
weighting  of,  173 
Woolen  goods,  injury  to  by  alkaline  solu- 
tions, 158 
Woolen  industry,  chief  products  of,  74 
fibers  used  in,  74 

magnitude  of  in  the  United  States,  7? 
Woolen  yarn  manufacture,  processes  in, 

108 
Woolen  yarns,  count  of,  1004 
Woolsack,  origin  of,  3 
Worsted  yarns,  count  of,  1005 


X 


Xylolin,  846 


Yama-mai  silk,  257 

Yannovitz  cotton,  390 

Yarn  and  cloth,  analysis  of,  998 

Yarn  counts,  comparison  of,  1019 

Yarn-testing  machines,  453 

Yellow  waste  silk,  254 

Yucca  fiber,  893 

Z 

Zeolite  water  softening,  303 
Zigarra  wool,  81 


OATE  DUE 


Demco,  Inc  38-293 


t»  1874-1931. 

heir  physicalf 
Lcal  propertiest 

•  • •  4th  ed«  y 

York,  J.  Wiley  S 
.  ]  1924. 
053  p.  incl. 


18548 


TS  1540.M43  1924 


3  9358  00018548  5 


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