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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 . 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 . 157 

Straw 0.325 

Soda wood pulp . 323 

Sulfite wood pulp . 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 



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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 . 

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 



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 



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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 '^^ 

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 
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^aJl l ^^' M w^p al w j ^8 )! li^! (gi^w y^- l w 



nJitu i i mi mm 



^-, 



■ fa»- k.^.-.n.^,. ||, ||-' ii - g iyn n --'Tf ia| 



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 


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 . 

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



STRENGTH AND ELASTICITY 



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) 10 15 20 25 30 35 

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 



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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 










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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 . 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) . 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 . 
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 




-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 . 

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 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 . 

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 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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1 



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 





45 




30 





30 




10 





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 



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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.) 







f Bj i ji i L jji ^ i ^^ P ^ 1 ii - ^ii uj i Ji m iJii 



'< r3 f jf . n iMm^. t . m jj r*' ^f m 






r ^V - ^vji « ^nj> m ..^m '! .i0 ii .^-mm ' .m r >»-'.Mm f m^^ 




•-'•'^-■••,-i-;tn , „-i- i,^ , ,, -i-,iii,'^,^-fi k uik i 'r A?u t-Mi!-m i ^ {i i fh-'-ff — -tn r-ii i H ii 'm inrtr- i '^'S "■•-'"•"■••'- ■''-''■•-'^'^■'•^■i '^i i'*"'-^'^"'-^-'-*-'"- --—^ 



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 . 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 . 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 
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 
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 
275 


Ash 


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 + = 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 . 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 


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 


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 





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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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 . 

Raw linen 27 . 7 

Raw jute 28.4 

Bleached silk 36 . 5 

Bleached and mordanted wool 50. 

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 


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 


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 




w ww fe g g ^ **' '- ^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 . 50 

Flying on card . 22 

Toppings on card 2 . 00 

Total on card 5 . 32 

Drawing (3 processes) . 33 

Slubber frame 0.08 

Intermediate frame . 06 

Roving frame . 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: 



L I 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 


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 


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 


000640 


New Orleans 


000775 


Texas 


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 


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 thi