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ANIMAL   AND  VEGETABLE 

FIXED-OILS,  FATS;  BUTTERS, 
-AND  WAXES:- 

THEIR  PREPARATION  AND   PROPERTIES, 


AND   THE 


0f 


BY 

C.    R.    ALDER    BRIGHT, 

D.Sc.  (LOND.),  B.Sc.  (VicT.),  F.R.S., 

LECTURER  ON   CHEMISTRY  IN   ST.  MARY'S  HOSPITAL  MEDICAL  SCHOOL,   LONDON ;     EXAMINER   IN 
"SOAP"   TO  THE  CITY  AND  GUILDS  OF  LONDON  INSTITUTE. 


Witb  144  Illustrations* 


OF  THE 

UNIVERSITY 


LONDON: 

CHARLES   GRIFFIN    &    COMPANY,    LIMITED; 

EXETER^  STREET,    STRAND. 

1894. 

[All  Rights  Reserved.] 


bl 


€         OF  THE  *"        Ny 

CVERSITT) 
OF  J 


PREFACE 


The  complete  discussion  of  the  Sources,  Production,  and 
General  Technology  of  the  numerous  substances  included  in 
the  term  Oils,  and  of  the  intimately  associated  Fats,  Butters, 
and  Waxes  (all  of  which  are  practically  oils  when  melted), 
would  require  far  more  space  than  is  compatible  with  the 
limits  of  the  present  ^or-k';  it  has  accordingly  been  found 
indispensable  to  make  a  selection  from  this  wide  field,  as 
the  result  of  which  the  subjects  now  dealt  with  are 
narrowed  down  to  the  Animal  and  Vegetable  Fixed  Oils 
and  allied  substances  ;  whilst  Mineral  Oils,  Products  of 
Distillation,  Essential  Oils,  and  various  analogous  materials 
are  only  discussed  in  so  far  as  they  are  associated  with  the 
Fixed  Oils  in  their  technological  applications.  For  the 
same  sufficient  reason  minute  details  respecting  the  various 
special  tests  employed  in  the  practical  examination  of  oils, 
&c.,  for  adulterations  have,  as  a  rule,  been  omitted ;  as  also 
have  the  descriptions  of  the  distinctive  properties  and 
qualities  of  the  individual  oils  and  fats,  excepting  in  a 
comparatively  small  number  of  typical  cases.  In  short,  the 
object  aimed  at  has  rather  been  to  give  general  descriptions 
of  the  methods  whereby  Animal  and  Vegetable  Oils  and  Fat 
are  obtained  from  natural  sources,  of  their  leading  practical 
applications  and  uses,  and  of  their  chief  physical  and 
chemical  properties  and  reactions,  than  to  enter  into  special 
details,  and  to  discuss  minutely  the  analytical  tests  and 
processes  applicable  in  each  separate  case  for  the  detection 
of  adulteration. 


VI  PREFACE. 

The  literature  relating  to  the  chemistry  and  technology 
of  fixed  oils  arid  fats  is  already  voluminous,  and  yearly 
increases  considerably  in  magnitude,  being  mostly  dispersed 
throughout  the  pages  of  numerous  scientific  and  technical 
serials.  Amongst  the  periodicals  of  this  description  consulted 
for  the  purpose  of  gathering  together  to  some  extent  these 
scattered  results  and  items  may  be  more  particularly 
mentioned  : — 

The  Journal  of  the  Society  of  Chemical  Industry. 

The  Journal  of  the  Society  of  Arts. 

The  Journal  of  the  Chemical  Society. 

The  Analyst. 

The  Chemical  News. 

Zeitschrift  fur  angewandte  Chemie. 

Berichte  der  Deutschen  Chemischen  Gesellschaft. 

Dingler's  Polytechnisches  Journal. 

Biedermann's  Technisch-Chemisches  Jahrbuch. 

Moniteur  Scientiftque. 

Bulletin  de  la  Societe  Chimique  de  Paris. 

Comptes  rcndus. 

Besides  many  others  in  which  papers  bearing  on  the  matters 
in  hand  appear  from  time  to  time.  Various  text-books  and 
technical  dictionaries  previously  published  in  this  country 
or  abroad  have  also  been  freely  consulted  with  the  object  of 
rendering  the  present  work  as  complete  as  possible,  with 
due  regard  to  the  limits  of  space.  In  particular  the  author 
desires  to  express  his  indebtedness  to  the  following  works: — 

Schadler,  Technologic  der  Fette  und  Oele*    Berlin,  1883. 

Allen,  Commercial  Organic  Analysis,  vol.  ii.,  Second 
edition.  London,  1886. 

Schadler,  Untersuchungen  der  Fette  und  Oele*  Leipzic, 
1889. 

Benedikt,  Analyse  der  Fette  und  Wachsarten,  Second 
edition.  Berlin,  1892. 

*  Whilst  the  present  book  was  in  the  press  the  two  works  by  Schadler 
above  mentioned  have  been  incorporated  into  a  single  volume,  edited  by 
P.  Lohmann  after  the  decease  of  the  original  author. 


PREFACE.  Vll 


To  the  firm  of  Kose,  Downs,  &  Thompson,  of  Hull,  the 
author  is  greatly  indebted  for  numerous  illustrations  of  the 
most  recent  and  effective  forms  of  oil  mill  machinery,  as 
well  as  for  valuable  information  concerning  their  use  in  oil 
extraction  generally.  In  similar  fashion  be  desires  to  thank 
Messrs.  Neill  &  Sons,  of  St.  Helens,  for  a  variety  of  specially 
made  drawings  of  appliances  used  in  soap  manufacture; 
Messrs.  S.  H.  Johnson,  of  Stratford,  for  drawings  of  the 
newest  forms  of  filter  presses ;  and  Messrs.  E.  Cowles  &  Co., 
of  Hounslow,  for  cuts  of  improved  candlemaldng  machines. 

C.  R.  ALDER  WRIGHT. 

LONDON,  October,   1893. 


€^E  LIBR^PT^ 
OF  THE  X 

;VERSITY) 
OF  J 


TABLE    OP    CONTENTS 


1.  General  Composition  and  Nature  of  Oils,  Butters,  Fats, 
Waxes,  and  Allied  Substances. 


CHAPTER  I. 

THE  SOURCES  AND  GENERAL 
NATURE  OF  NATURAL  AND 
ARTIFICIAL  OILS. 

Meaning  of  the  Terms  "Oil," 
"Fat,"  "Butter,"  and  "Wax," 

Sources  and  General  Nature  of 
Oils, 

Nature  of  Sapoiiification  Changes, 

Classification  of  Oils,  Fats, 
Waxes,  &c. ,  according  to  Chem- 
ical Composition, 

CHAPTER  II. 

ALCOHOLIFORM  SAPONIFICATION 
PRODUCTS  OF  OILS,  FATS, 
WAXES,  &c. 


Glycerol,  Glycerides,  Hydrolysis 

of  Glycerides,   ....  7 

Fatty  Alcohols,  Ethylic  Series,  &c.,  13 

Glycols, 18 


CHAPTER  III. 

ACID  SAPONIFICATION  PRODUCTS 
OF  OILS,  FATS,  WAXES,  &c. 

Fatty  A  cids-  Acetic  Family,  .  18 

Oleic  Family,  .  .  .  24 

Linolic  Family,  .  .  30 

Linolenic  Family,  .  .  36 

Glycollic  Family,  .  .  37 

Ricinoleic  Family,  .  .  39 

Oxystearic  Acids,                  .  .  43 


2.  Physical  Properties  of  Oils,  Fats,  Waxes,  &e. 


CHAPTER  IV. 
GENERAL  PHYSICAL  CHARACTERS. 

Phy  sical  Texture  and  Consistency ; 
Cohesion  Figures,  . 

Taste,  Odour,  and  Colour,  . 

Action  of  Polarised  Light;  Re- 
fractive Index, 

Solubility  of  Oils,  Fats,  &c.,  in 
various  Solvents, 

Thermometric  Scales,  . 

Methods  used  in  the  Determina- 
tion of  Fusing  and  Solidifying 
Points,  ..... 

Freezing  and  Melting  Points  of 
Oils,  &c., 

CHAPTER  V. 
SPECIFIC  GRAVITY  AND  VISCOSITY. 


Determination  of  Specific  Gravity,    77 
Construction  of  Tables  of  Errors 
for   Hydrometers   and   Hydro- 
static Balances,         .         .         .     82 
Hydrometer  Scales,      .         .         .84 
Relative  Densities  of  the  Principal 

Oils,  Fats,  &c.,          .  .     86 

Classification  of  Oils,   Fats,  &c., 
according     to     their    Relative 
Densities,          .         .         .         .89 
Variation  of  Density  of  Oils,  &c., 

with  Temperature,   .         .         .92 
Viscosimetry ;  Mechanical  Testing 

Arrangements, .         .         .         .94 
Efflux  Viscosimeters,  .  .95 

Standards  of  Efflux  Viscosity,      .   101 
Relative  Viscosity  of  Oils,  &c.,    .   102 
Determination    of     Viscosity    in 
Absolute  Measure,    .         .         .   107 


CONTENTS. 


§  3.  Chemical  Properties  of  Oils,  Fats,  Butters,  and  Waxes. 


CHAPTER  VI. 

PROXIMATE  CONSTITUENTS  AND 
THE  METHODS  USED  FOR  THEIR 
EXAMINATION  AND  DETERMIN- 
ATION. 

Compound  Nature  of  Oils,  Fats, 
and  Waxes ;  Variations  in  Com- 
position with  Circumstances  of 
Natural  Formation,. 


110 


Methods  Employed  for  Separa- 
ting Constituents,  .  .  .112 

Determination  of  Free  Fatty 
Acids;  Free  Acid  Number,  .  116 

Determination  of  Unsaponifiable 
Constituents,  .  .  .  .119 

Determination  of  Water,      .         .    122 

Adulteration  of  Fats  with  sus- 
pended Matters, 


Sulphurised     and 
Constituents,    . 


Phosphorised 


123 
123 


CHAPTER  VII. 

CHEMICAL  REACTIONS  or  OILS, 
FATS,  £c.,  AND  THEIR,  USES  AS 
TESTS  OF  PURITY,  &c. 

Effect    of    Heat    on    Oils,    &c. ; 

Flashing  Point,         .         .         .125 
Characteristic  Oxidation  Products,  128 
Spontaneous   Oxidation   of    Oils, 
Fats,     &c. ;     E  fleet     of     Light 

thereon, 129 

Spontaneous  Combustion,     .          .132 
Film  Test;  Livache's  Test,  .         .   133 
Chemical  Changes  occurring  dur- 
ing drying  of  Oils,    .         .         .   134 
Elaidin  Reaction ;   Legler's  Con- 
sistency Tester,         .         .         .137 
Nitric  Acid  Test,         ,         .         .139 
Zinc  Chloride  Reaction  and  Colour 
Test;  Action  of  Zinc  Chloride 
on  Oleic  Acid,  .          .         .         .141 


Action  of  Sulphuric  Acid  on  Oils 
and  Fats  ;  Turkey  Red  Oils,  .  143 

Maumene's  Sulphuric  Acid  Ther- 
mal Test,  .  .  .  147 

Various  Colour  Reactions,  .         .    151 

Sulphur  Chloride  Reaction;  Vul- 
canised Oils,  .  .  .  .154 

CHAPTER  VIII. 

QUANTITATIVE  REACTIONS  OF 
OILS. 

Koettstorfer's  Test— Total  Acid 
Number,  .....  157 

Classification  of  Oils,  &c.,  accord- 
ing to  their  Saponification  Equi- 
valents, .....  159 

Practical  Determination  of  Saponi- 
fication Equivalents  of  Glycer- 
ides,  &c.,  .... 


159 
163 


Proportion  of  Fatty  Acids  formed 
by  Saponification,  . 

Hehner's  Test;  Insoluble  Acid 
Number,  .  .  ...  .  166 

Practical  Determination  of  the 
amount  of  Fatty  Acids  formed 
on  Saponification,  .  .  .  167 

Corrections  for  An  hydro  Deriva- 
tives, Free  Acids,  and  Unsa- 
ponifiable Matters, 


170 

172 


Mean  Equivalent  of  Fatty  Acids 

contained  in  Soap,    . 
Reichert's    Test    and    Modifica- 
tions thereof,    .         .         .         .173 
Bromine  and  Iodine  Absorption ; 

Bromine  Process,  .  .  .  176 
Iodine  Process  ;  Hiibl's  Test,  .  179 
Iodine  Numbers  of  Oils,  Fats, 

&c.,  .         .         .         .         .180 

Acetylation  Test ;  Benedikt  and 

Ulzer'sTest,  .  .  .  .186 
Methyl  Iodide  Test;  Zeisel's 

Test, 191 

Tabulated  results  of  the  various 

Quantitative  Tests,  .         .         .  194 


§4.  Processes  Used  for  Extracting,  Rendering,  Refining, 
and  Bleaching  Oils,  Fats,  &e. 


CHAPTER  IX. 

EXTRACTION  OF  OILS  FROM  SEEDS, 
&c.,  BY  PRESSURE  OR  SOLVENTS. 

Earlier  forms  of  Press, 


199 


Elbow,       Wedge,      and      Screw 

Presses, 202 

Hydraulic  Press,  .         .         .  207 

Composition  of  Oilcake,        .         .213 
Oil  Mill  Plant ;  "  Unit  "  Mill,     .  214 


CONTENTS. 


XI 


Crushing  Rolls  and  Edge 
Runners,  .  .  .  .218 

Kettle  ;  Moulding  Machine,         .  221 

Faring  Machine  ;  Supplementary 
Appliances,  ....  223 

Decortication,      ....  224 

Filter  Presses,      .     '   . 


Separation  of  Solid  Stearines  from 


226 
229 


Oils,  &c.,  . 

Manufacture  of  Lard  Oil,  and 
Allied  Products,  .  .  .231 

Extraction  of  Oil  from  Seeds,  Oil- 
cake, &c.,  by  Solvents,  .  .  231 

Extraction  of  Grease  from  Engine 
Waste,  &c.,  .  .  .  .  236 

Determination  of  Fat  in  Seeds, 
&c., 237 

Proportion  of  Fatty  Matter  Con- 
tained in  Seeds,  &c.,  .  .  241 

CHAPTER  X. 

A  NIMAL  FATTY  TISSUES  :  EXTRAC- 
TION or  OILS  AND  FATS 

THEREFROM. 

Rendering  of  Fatty  Tissues  by 
Dry  Fusion,  .  .  .  .246 

Rendering  of  Fatty  Tissues  by 
Heating  with  Water  or  Steam 


under  ordinary  Atmospheric 
Pressure,  ....  247 

Rendering  under  Increased 
Pressure,  .  .  .  .250 

Extraction  of  Fat  from  Bones,     .  251 

CHAPTER  XI. 

REFINING  ANDBLEACHING  ANIMAL 
AND  VEGETABLE  OILS,  FATS, 
WAXES,  &c. 

Suspended  Matters,     . 
Dissolved  Matters, 
Sulphuric      Acid      Process      for 
Refining  Oils,  &c., 


Alkaline  Refining  Processes, 
Utilisation  of  "  Foots," 
Clarification, 
Bleaching  Oils  and  Fats, 
Wax  Bleaching,   . 

CHAPTER  XII. 

RECOVERY  OF  GREASE  FROM 

"SUDS,"  &C. 

Modes  of  Treating  Soap  Suds, 
Analysis  of  Yorkshire  Grease, 
Distilled  Grease, 
Engine  Waste  Grease, 


254 

256 

259 
260 
261 
262 
263 
268 


270 
273 

277 
279 


§  5.   Classification  and  Uses  of  Fixed  Oils,  Fats,  Waxes,  &e. ; 
Adulterations. 


CHAPTER  XIII. 

CLASSIFICATION. 

Classification   according   to   Tex- 
ture,   Sources,    and     Essential 
Chemical  Nature.     .         .         .281 
CLASS    I.  Olive  (Almond)  Class; 
Vegetable  Expression 
Oleines,      .         .         .282 
II.  Rape  (Colza)  Class,      .  284 
„      III.  Castor  Class,         .         .  284 
,,       IV.  Animal       Non-Drjdng 

Oils- Lard  Oil  Class,    285 
,,         V.  Sesame  or  Cotton  Seed 
Class  —  Vegetable 
Semidrying  Oils,         .  286 
Lesser    Known    Vege- 
table Oils,  .         .         .287 
,,       VI.   Drying  Oils  —  Linseed 

O'il  Class,  .         .         .290 
,,     VII.   Train,  Liver,  and  Fish 

Oils,  .         .         .         .292 


,,  VIII.  Vegetable  Butters, 

Fats,  Waxes,  &c.,      .  295 

Lesser  Known  Vege- 
table Butters,  &c.,     .  296 

„       IX.  Animal   Fats— Tallow, 

Lard,  and  Butter  Class,  298 

,.         X.  Animal    Oils  —  Sperm 

Oil  Class,  .         .         .299 

,,       XI.    Vegetable     Nonglyce- 

ridic  Waxes,      .         .   301 

,,     XII.  Beeswax  and  Sperma- 
ceti Class,  .         .   301 

CHAPTER  XIV. 

PRINCIPAL  USES  OF  OILS  AND 
FATS,  &c. 

Classification  according  to  Uses, .  302 
Edible  and  Culinary  Uses  of  Oils, 

Fats,  &c 303 

Cotton  Seed  Stearine  ;  Vegetable 

Lards,       .  .  305 


Xll 


CONTENTS. 


Manufacture  of  Hog's  Lard,         .  306 
Manufacture  of  Artificial    Lard 

and  Batter,       .         .         .         .307 
Utilisation  of  Fatty  Matter  from 

an  Ox, 311 

Lamp  Oils, 312 

Drying  Oils  used  in  making  Paints 

and  Varnishes,          .         .         .  313 
Blown  Oils — Oxygen  Process,       .  319 
Miscellaneous  Uses  of  Oils,  Fats, 
&c. ;     Manufacture    of    Lubri- 
cants,         321 

Analysis  of  Lubricating  Oils  and 

Greases, 328 

Turkey  Red  Oils;  Analysis,         .  330 
Currier's   Grease,   Sod  Oils,    and 

Degras, 336 

Manufacture  of  Lanolin,       .         .  337 


CHAPTER  XV. 
ADULTERATION  OF  OILS  AND  FATS. 

Methods  employed  in   Detecting 

Adulterations,  .         .         .340 

Relative  Values  of  Oils,       .         .  342 
General  Characters  of  Olive  Oil 
andTests  for  Adul- 
terations thereof, .  342 
,,         Rape  Seed  and  Colza 

Oil,  .  .  .348 
Linseed  Oil,  .  .  349 
Sperm  Oil,  .  .  353 
Tallow,  .  .  .  354 
Beeswax,  .  .  357 

Spermaceti,       .         .  359 


6.  The  Candle  Industry. 


CHAPTER  XVI. 

MATERIALS  USED  IN  CANDLE- 
MAKING. 

Origin  of  Candles ;  Combustible 
Materials,  .  • .  .  .  362 

Manufacture  of  ' '  Stearine ;  "  the 
Chevreul-Milly  Process, 


Composition  and  Analysis  of 
"Rock," 

Milly- Autoclave  Process,     . 

Analysis  of  Red  Oils,  Separation 
Cake,  and  Similar  Products,  . 

Sulphuric  Acid  Process, 


364 

371 
373 

378 

380 


Hydrolysis     of     Glycerides     by 

Water  only,      .         .         .         .385 
Utilisation  of  Red  Oils,        .         .  386 

CHAPTER   XVII. 

MANUFACTURE  OF  CANDLES,  TAPERS, 
AND  NIGHT  LIGHTS. 

Basted  and  Drawn  Wax  Candles, 

Tapers,  &c.,  .  .  .  .388 
Dip  Caudles;  Dipping  Machinery,  390 
Wicks ;  Wick  Pickling,  .  .  394 
Moulded  Candles  ;  Handmade,  .  395 
Continuous  Moulding  Machines,  398 
Night  Lights  and  Medicated 
Candles, 406 


§  7.  The  Soap  Industry. 
CHAPTER  XVIII.  CHAPTER  XIX. 


MATERIALS  USED  IN  THE  MANU- 
FACTURE OF  SOAP. 

Fatty  Matters ;  Alkalies,  .  .  408 
Causticising  Process,  .  .  .411 
Valuation  of  Alkalinity  of  Leys,  414 
Corrections  for  Impurities,  .  .419 
English,  French,  and  German 

Decrees, 420 

Calculations,  .  .  .  .421 
Formulae, 425 


SOAPMAKING  PLANT. 

Heating    Appliances ;    Free-fired 

Soap  Coppers,  ...  426 

Morfit's  Steam  Twirl,  .         .  429 

Steam-heated  Soap  Coppers,  432 

Curb  and  Fan,      ...  433 

Soap  Pumps,        .         .         .  434 

Soap  Frames,        .         .         .  434 

Barring  and  Slabbing,          .  437 

Crutching, 438 


CONTENTS. 


Xlll 


Toilet  Soap  Machinery  ;  Remelt- 

ing, 441 

Stamping,    .....  444 

Transparent  Soaps,       .         .         .  445 

Milling, 446 

Plotting, 448 

CHAPTER  XX. 

MANUFACTURE  OF  SOAP. 

Soapmaking     Processes ;     Direct 

Neutralisation,  .  .  .  449 
Calculations,  ....  454 
Processes  in  which  the  Free  Gly- 

cerol  is  retained  ;  Cold  Process 

Soaps,  .....  456 
Soft,  Hydrated,  and  Marine 

Soaps,  .....  459 
Calculations,  ....  464 
Processes  in  which  the  Glycerol 

is  separated  ;  Curd  Soaps,  .  466 
Graining,  .....  469 
Fitted  and  Mottled  Soaps,  .  .  470 
Special  Varieties  of  Soap ;  Rosin 

Soaps,  Silicated  Soaps,  &c.,  .  473 
Toilet  and  Fancy  Soaps;  Milled 

Soaps, 478 

Transparent  Soaps,  &c.,  .  .  481 
Neutralised  Soaps,  .  .  .483 


CHAPTER  XXI. 

GENERAL  CHEMISTRY  OF  SOAP — 
SOAP  ANALYSIS. 

General     Properties     of     Soaps ; 

Hydrolysis  of  Soap  Solutions,  484 
Reaction  of  Soap  Solution  or  of 

Fused  Soap  on   Inorganic  and 

other  Salts,  .  .  .  .488 
Methods  Used  in  the  Analysis  of 

Soap, 492 

General  Scheme  for  Analysis,  .  506 
Composition  of  Manufacturers', 

Laundry,  and  Toilet  Soaps,  &c.,  508 
Classification  of  Toilet  Soaps 

according  to   amount  of   Free 

Alkali  present,          .         .         .512 


CHAPTER  XXII. 

GLYCEROL    EXTRACTION — MANU- 
FACTURE OF  GLYCERINE. 

Sources  of  Glycerol ;  Extraction, .  513 
Valuation  of  Commercial  Glycer- 
ine ;  Estimation  of  Glycerol  in 
Watery  Solution,      .         .         .516 
Glycerol  in  Soap  Leys,         .         .  522 


INDEX, 


525 


LIST  OF  ILLUSTRATIONS. 


FIG.  PAGE 

1.  Cohesion  Figures,    .......         48 

2.  Capillary  Tubes  used  for  determining  Fusing  Points.        .  .         60 

3.  Mode  of  attachment  to  Thermometer,         .  .             .              .61 

4.  Mode  of  heating  the  arrangement  in  Water,  .             .             .61 

5.  Another  Mode,          .......         62 

6.  Olberg's  Water  Bath,  ......         62 

7.  Bensemann's  Tubes,  .             .              .             .             .             .63 

8.  Pohl's  Method,         .......         64 

9.  Cross  and  Bevan's  Method,  .....         63 

10.  Lcewe's  Method,       .  .             .             .             .             .             .65 

11.  Mohr's  Hydrostatic  Balance,  .....         78 

12.  Westphal's  do.,                       .....         79 

13.  Lefebre's  Oleometer,  ......         80 

14.  Hot  Air  Bath  for  use  with  Westphal's  Hydrostatic  Balance,        .          81 

15.  Ambuhl's  Arrangement,       ......         81 

16.  Schiibler's  Viscosimeter  (Efflux  Method),  .          "   .  .95 

17.  Schmid's  do.,                .             .             .             .             .             .96 

18.  Redwood's         do.,  .             .             .             .             .             ,97 

19.  Do.  do.,               ......         98 

20.  Allen's  Modification  of  Viscosimeter,          .  .             .             .98 

"21.  Engler's  Viscosimeter,         ......         99 

22.  Hurst's              do.,                .             .             .             .             .             .100 

•23.  Eedwood's  Chart  of  Viscosity  of  Oils,         .              .              .             .103 

24.  Do.  do.              do.,                      ....       104 

25.  Lepenau's  Leptometer,         ......       107 

26.  Traube's  Apparatus,  .             .             .             .             ,             .109 

27.  Chattaway's  Tubes,  ......        120 

28.  Abel's  Flashing  Point  Apparatus,  .  .             .             .             .126 

29.  Pen  sky's  Modification  of  same,        .....       127 

30.  Legler's  Consistency  Tester,  .             .             .             .             .139 

31.  Apparatus  for  Maumeue's  Test,      .....       147 

32.  Jean's  Thermeleometer,       .  .             .             .             .             .151 

33.  Benedikt  and  Griissner's  Apparatus  for  Zeisel's  Test,        .  .       193 

34.  Elbow  Press,  .......       202 

35.  Wedge  Press,  Front  Elevation,       .  ;             .             .  |        .       203 

36.  Do.          Side         do.,  .            .            .            .        •'" :.       203 

37.  Do.          Longitudinal  Section,  .             .             .             .204 

38.  Screw  Press  (English),         ".  .             .             .             .             .       205 

39.  Do.          (German),         .  ...             .             .206 

40.  Hydraulic  Press  (German,  empty),  .             .                          .       208 

41.  Do.  (after  the  ram  has  risen),              .             .             .       209 

42.  Do.  (English,  Handworked),  ....       210 

43.  Do.  (Anglo-American  System),            .             .             .211 


LIST    OF    ILLUSTRATIONS.  XV 

FKi.  PAGK 

44.  Hydraulic  Press,  Plan  and  Longitudinal  Section  of  Plate,  .       212 

45.  Do.  Cross  Section  of  Plate,      ....       212 

46.  Oil  Mill  Plant;  Ground  Plan  of  16- press  Installation,       .  .       216 

47.  Crushing  Rolls,        .  .  .  .  .  .  .218 

48.  Edge  Runners,          .......       '219 

49.  Kettle,          ........       220 

50.  51.  Envelopes,  .......       221 

52.  Paring  Machine,       .......       222 

53.  Decortication  of  Cotton  Seeds,        .....       224 

54.  ,,  of  Castor  Beans,        .  .  .  .  .224 

55.  Disintegrator  and  Elevator,  .....       225 

56.  Filter  Press,  .......       226 

57.  Do.,  Front  Elevation  of  Plates,       ....  226 

58.  Do.,  Sectional  do.,     .  .  .  .  .  226 

59.  Do.,  with  Pyramid  Drainage  Surfaces,       .  .  .  227 

60.  Do.,  do.  do.,  .  .  .  228 

61.  Do.,  Small  Handworked,    .....  229 

62.  Apparatus  for  Oil  Extraction  by  Solvents,  .  .  .       233 

63.  Heyl's  Distillation  Apparatus,         .....       234 

64.  Deitz's  Extraction  Apparatus,         .....       235 

65.  Plant  for  Cleansing  Engine  Waste,  ....       237 

66.  67.  Soxhlet's  Tube  (two  forms),       .  .  ...  .238 

68.  Allihn's  Reflux  Condenser,  .  .  .  .  .239 

69.  Fruhling's  form  of  Soxhlet  Tube,    .  .  .  .  .239 

70.  Reservoir  for  same,  ......       240 

71.  Laboratory  Extraction  Apparatus,  ....       240 

72.  Honig  and  Spitz's  Apparatus,          .....       240 

73.  Wilson's  Digester,    .......       250 

74.  Barrel  Digester  for  Extracting  Fat  from  Bones,    .  .  .       252 

75.  Leuner's  Apparatus,  ......       253 

76.  Free-fired  Pan  for  Boiling  Oil,         .....       316 

77.  Steam-heated  Oil  Kettles,   .  .  .  .  .317 

78.  Open  Pan  used  in  manufacturing  Stearine,  .  .  .       366 

79.  80.  Crystallising  Pans,         .  .  .  .  .  .367 

81.  Hot  Press,    ........  368 

82.  Plant  for  Saponification  by  Open  Pan  Process,       .             .             .  369 

83.  Plant  for  Hydrolysis  of  Fats  by  means  of  Sulphuric  Acid,            .  381 

84.  Knab's  Apparatus  for  Distillation  by  Superheated  Steam,             .  382 

85.  Plant  for  Hydrolysis  of  Glycerides  by  Superheated  Steam,          .  386 

86.  Basting  Wheel,         .......  388 

87.  Drawing  Tapers,      .......  389 

88.  Knife  for  Cutting  off  Butt  Ends,    .  .  .  .  .390 

89.  Rotating  Candle  Dipper,     ......  390 

90.  Edinburgh  Wheel,  .......  391 

91.  Wick-holder,            .......  392 

92.  93.  Dipper  with  Movable  Cauldron,  393 


XVI  LIST    OF    ILLUSTRATIONS. 


PAGK 


FIG. 

94.  Candle  Mould,        .......  396 

95.  Hand  Moulding  Frame,     ......  396 

96.  Mode  of  fixing  Wick,        ....  396 

97.  98.  Improved  Moulding  Frame,    .....  396 
99.  Royan's  Continuous  Wick  Moulding  Machine,    .             .             .  397 

100.  Camp's  Moulding  Wheel,              .....  398 

101.  Piston  of  Moulding  Machine,        .....  399 

102.  Moulding  Machine  and  Nippers,  .....  400 

103.  Self -fitting  Butt  End,         ......  402 

104.  Machine  for  Moulding  Self-fitting  Butt  End  Candles,     .             .  403 

105.  Turnover  Machine,             ......  404 

106.  Polishing  Machine,            ......  405 

107.  Soap  Tank  for  holding  Ley,  .  .  .  .  .412 

108.  Free-fired  Soap  Pan,          ......  427 

109.  Another  form  of  do.,          ......  427 

110.  Steam-heated  Pan,             ......  428 

111.  Morfit's  Steam  Twirl,        .  .  .  .  .  .429 

112.  Soap  Copper,          .             .             .             .             .             .             .  430 

113.  Morfit's  Steam  Series,        ......  430 

114.  Modern  form  of  Steam-heated  Pan,           ....  431 

115.  Plan  of  same,         .......  432 

116.  Fan,           ........  434 

117.  Rotary  Soap  Pump,           ......  434 

118.  Mode  of  building  up  Wooden  Frames,     ....  435 

119.  Galvanised  Iron  Frames,  ......  435 

120.  Improved  form  of  Steel  Soap  Frame,       ....  436 

121.  Cutting  Soap,         .                          .....  437 

122.  Looped  Wire  used  for  cutting,     .....  437 

123.  Scribe,        ........  438 

124.  Slabbing  and  Barring  Machine,    .....  439 

125.  Padded  Frame,      .......  440 

126.  Hand  Crutch,        .......  440 

127.  Crutching  Machine,           ......  440 

128.  Jacketted  Crutching  Machine,      .....  440 

129.  130.  Series  of  Crutching  Pans,      .             .             .             .             .442 
131,  132.  Neill  and  Son's  Remelter,    .             .             .             .             .  44£ 

133.  Hand  Tablet  Stamping  Machine,              ....  444 

134,  135.  Steam  Stamping  Machine,     .....  445 

136.  Rutschmann's  Stripping  Machine,            ....  446 

137.  Soap  Mill,  ........  447 

138.  Beyer's  Plotting  Machine,  .  .  .  .  .448 

139.  Steam  Jacketted  Pan  and  Agitator,          .  .  .  .452 

140.  141.  Hawes'  Boilers  for  Cold  Process  Soaps,        .  .  .457 

142.  Dunn's  Plant  for  making  Hydrated  Soaps  under  Pressure,         .  463 

143.  Alder  Wright's  Chart  of  Hydrolysis  of  Soap  Solutions,              .  488 

144.  Gerlach's  Vaporimeter,     .             .             .             .             .'  518 


1.  General  Composition  and  Nature  of 
Oils,  Butters,  Fats,  Waxes,  and 
Allied  Substances. 


CHAPTER    I. 

THE   SOURCES  AND  GENERAL  NATURE   OF  NATURAL 
AND  ARTIFICIAL  OILS,   &c. 

AMONGST  the  alchemists  the  term  "  oil "  had  a  somewhat  wider 
range  of  application  than  is  usual  at  the  present  day,  including 
various  inorganic  substances,  such  as  "  oil  of  vitriol."  Similarly 
"  butter  of  antimony  "  and  "  butter  of  tin  "  were  metallic  deri- 
vatives entirely  dissimilar  from  cow's  butter  in  constitution, 
although  resembling  it  in  physical  consistency.  Even  when 
such  wholly  inorganic  compounds  are  excluded,  the  term  "  oil " 
has  still  an  extremely  elastic  meaning,  being  employed  to 
designate  a  very  large  variety  of  liquid  substances,  natural 
and  artificial,  which  have  but  few  features  in  common  beyond 
the  fact  that,  being  all  organic  in  character,  they  are  capable  of 
burning  with  more  or  less  facility  under  suitable  conditions ; 
whilst  with  but  very  few  exceptions  they  are  practically  in- 
soluble in  water,  so  as  to  be  incapable  of  permanent  solution 
therein  ;  being  as  a  rule  lighter  than  water,  when  agitated 
therewith  an  emulsion  forms,  from  which  the  water  and  oil 
gradually  separate  011  standing,  the  latter  usually  floating  as  a 
separate  layer  on  the  former. 

The  term  "fatty  matter,"  or  more  shortly  "fat,"  is  applied  to 
substances  which  are  more  or  less  of  a  soft  solid  character  at 
the  ordinary  temperature,  but  on  gently  heating  pass  to  liquids 
closely  resembling  fluid  oils  in  general  characters ;  "  butters  " 
being  specially  soft  varieties  of  such  fats  possessing  the  peculiar 
physical  texture  of  cow's  butter  at  the  atmospheric  temperature 
of  temperate  climates.  "  Waxes,"  on  the  other  hand,  possess  a 
somewhat  different  and  much  firmer  texture  at  the  ordinary 
temperature,  but  when  heated  melt  to  fluids  which  closely 
resemble  ordinary  liquid  oils  and  melted  fats  in  their  general 
physical  characters. 

1 


;  01 LS,    FATS,    WAXES,    ETC. 


Oils  proper  are  derived  from  animal,  vegetable,  and  mineral 
sources,  being  mostly  precontained  in  the  tissues,  seeds,  or  strata, 
&c.,  from  which  they  are  obtained  by  simple  mechanical  pro- 
cesses, such  as  pressure  or  pumping,  or  by  means  of  solvents, 
or  by  volatilisation  ;  certain  products  of  destructive  distillation, 
however,  are  also  ranked  amongst  oils — e.g.,  the  "light  oils," 
"  creosote  oils,"  &c.,  obtained  during  the  rectification  of  coal  tar; 
and  "shale  oils,"  "  bone  oil  "  (Dippel's  oil,  or  bone  tar),  "paraffin 
oils,"  "  rosin  oils,5'  and  similar  substances  formed  by  the  breaking 
up  of  more  complex  organic  matters  under  the  influence  of  heat. 
Somewhat  -similar  substances  (fusel  oils)  are  produced  by  ana- 
logous decompositions  occurring  during  fermentative  changes. 

Oils  capable  of  being  converted  into  vapour  by  the  application 
of  heat  wdthout  suffering  material  decomposition  (volatile  oils) 
are  for  the  most  part  either  artificial  products  of  destructive 
distillation,  natural  mineral  oils  (petroleum,  very  probably 
formed  underground  by  the  long-continued  action  of  intra- 
terrestrial  heat  on  subterranean  organic  matter),  or  "  essential " 
oils — i.e.,  volatile  odorous  matters  extracted  from  numerous  vege- 
table sources,  usually  by  distillation  along  with  water.  Fixed 
oils,  on  the  other  hand,  are  substances  not  volatile  without 
decomposition,  and  are  essentially  of  animal  and  vegetable 
origin ;  as  also  are  butters,  fats,  and  waxes  (which  practically 
become  fixed  oils  on  slightly  raising  the  temperature),  with 
the  exception  of  the  so-called  waxes  of  mineral  origin,  paraffin 
wax,  ozokerite,  cerasin,  &c.* 

From  the  point  of  view  of  general  chemical  composition,  oils, 
fats,  butters,  and  waxes  may  be  divided  into  two  leading  classes- 
— viz.,  those  consisting  of  carbon  and  hydrogen  only  (Jiydro- 
carbons);  and  those  containing  carbon,  hydrogen,  and  oxygen. 
Oils,  &c.,  of  the  former  class  are  practically  all  volatile  without 
decomposition  ;  those  of  the  second  class  are  in  some  cases 
volatile  without  change  (e.g.,  oxidised  essential  oils),  but,  as  a 
rule,  are  "  fixed,"  undergoing  destructive  distillation  when  heated, 
so  that  the  vapours  emitted  are  produced  in  consequence  of 
decomposition. 

Hydrocarbon  oils  include  a  large  number  of  "  essential  oils  " 
(in  which  oxidised  substances  are  often  present  along  with  hydro- 
carbons) ;  paraffin  and  petroleum  oils,  including  the  lightest  and 
most  volatile  distillates  of  the  "  benzoline  "  class,  "  burning  oils  " 
(kerosenes,  <fec.)  of  medium  volatility,  "lubricating  oils"  of 
higher  boiling  point,  and  paraffin  waxes,  Arc.;  coaltar  oils  of 

*  The  terms  "  fat "  and  "  butter  "  are  not  confined  to  the  fatty  matters 
obtainable  from  the  adipose  tissues  of  animals  and  the  milk  of  mammalia  ; 
thus,  various  vegetable  fats  and  butters  are  known,  e.g.,  Dika  fat,  Palm 
butter,  Shea  butter,  vegetable  tallow,  &c.  Similarly,  whilst  animal  waxes 
are  the  best  known  products  of  the  wax  class,  various  forms  of  vegetable 
wax  occur  in  nature  (e.g.,  Japanese  wax  and  Carnauba  wax). 


THE    SOURCES    AND    GENERAL   NATURE    OF    OILS,    ETC.  3 

various  kinds ;  and  other  analogous  products  of  destructive 
distillation,  from  which  various  "closed  chain"  hydrocarbons, 
(benzene,  naphthalene,  anthracene,  &c.)  are  isolable,  along  with 
many  other  kinds  of  hydrocarbons,  some  of  the  "  saturated " 
class  (paraffins,  indicated  by  the  general  formula  CnHon  +  2),  some; 
of  the  "  unsaturated "  classes  (CmH2n,  where  n  is  not  greater 
than  in}. 

Oxidised  oils  (including  fats,  butters,  and  waxes),  from  the  point 
of  view  of  chemical  constitution,  are  divisible  into  two  classes — 
viz.,  those  that  are,  and  those  that  are  not,  of  the  nature  of 
"  compound  ethers,"  or  substances  capable  of  undergoing  changes, 
of  the  character  of  that  known  as  "  saponification."  Oils  of  the 
first  class  are  again  divisible  into  two  groups — viz.,  Glycerides, 
or  oils,  &c.,  developing  glycerol  by  saponification ;  and  Non- 
glycerides,  or  oils  not  developing  glycerol  by  saponification,  but 
giving  rise  instead  to  some  other  alcoholiform  product.  As 
examples  of  these  two  groups  may  be  mentioned,  olive  oil, 
coker*  butter,  mutton  tallow,  cow's  butter,  Japanese  wax, 
linseed  oil,  colza  oil,  cod  liver  oil,  and  whale  oil,  essentially 
glyceridic  in  character  ;  and  oil  of  wintergreen  (chiefly  methyl 
salicylate),  beeswax  (mainly  myricyl  palmitate),  spermaceti 
(chiefly  cetylic  palmitate),  and  sperm  and  doegling  oils,  essenti- 
ally non-glyceridic  in  character. 

Oils,  &c.,  of  the  second  class  (non-saponifiable)  include  various 
oxidised  essential  oils  belonging  to  different  organic  families — 
e.g.,  aldehydes,  such  as  oil  of  bitter  almonds  (benzoic  aldehyde) ;. 
ketones,  like  oil  of  rue  (methyl  nonyl  ketone)  and  oil  of  tansy 
(methyl  octyl  ketone) ;  alcohols,  such  as  oil  of  geranium 
(geraniol)  ;  camphor  analogues,  such  as  oil  of  wormwood  (absin- 
thol) ;  and  resinoid  constituents.  Various  alcoholiform  sub- 
stances are  also  contained  in  the  free  state  in  natural  oils, 
greases,  &c.  ;  thus  woolgrease  contains  cholesterol,  and  amber- 
gris an  allied  body  ambreol ;  whilst  similar  substances  are  found 
in  small  quantity  in  many  vegetable  oils.  Higher  alcohols  (e.g., 
cetylic  alcohol)  are  often  present  in  the  free  state  in  marine 
cetacean  oils  ;  whilst  phenol  and  its  homologues  are  present  in 
coaltar  oils  and  other  products  of  destructive  distillation. 

SAPONIFICATION . 

Originally  the  term  "  Saponification "  was  used  to  designate 
the  chemical  changes  taking  place  when  soap  is  prepared  by 
the  action  of  alkalies  on  fixed  oils  and  fats  ;  but  subsequently  it 

*  Although  the  spelling  "  coker"  at  first  sight  looks  inelegant,  it  is  con- 
venient to  employ  it  instead  of  "  cocoa,"  in  order  clearly  to  distinguish  the 
product  of  the  cokernut  palm  (Cocos  nucifera)  from  that  of  the  cacao  (choco- 
late plant  yielding  the  beverage  cocoa)  and  the  coca  (yielding  the  alkaloid 
cocaine). 


4  OILS,    FATS,    WAXES,    ETC. 

has  been  extended  to  include  a  large  number  of  parallel  changes 
occurring  where  various  classes  of  "  compound  ethers  "  are  broken 
up  under  the  influence  of  alkalies  or  other  bases,  so  as  to  give 
rise,  on  the  one  hand,  to  the  metallic  salt  of  an  organic  acid,  and, 
on  the  other,  to  an  alcoholiform  complementary  product.  The 
following  equations  represent  typical  reactions  of  saponification, 
according  as'  the  alcoholiform  product  is  an  alcohol  of  the  mono- 
hydric,  dihydric,  trihydric,  or  tetrahydric  class : — 


Ethyl  Acetate. 

C2H5.O.C2H30 


Potassium  Potassium 

Hydroxide.  Acetate. 

K  .  OH    =      K  .  0  .  C2H30 


Ethylic 
Alcohol. 

+      C2H, .  OH 


Ethylene  Diacetate. 


Potassium 
Hydroxide. 


Potassium 
Acetate. 


2K.OH    =    2K.O.C2H,0 


Glycol. 

r      (OH 


Uiyceryl  Tristearate 
(Stearin). 


C3H5 


O.C1SH350 
O.C18H350 
O.C18H350 


Erythrol  Tetrabenzoate. 

O.C7H50 
O.C7H50 
O .  C7H5O 
O.C7H50 


4.  C4H 


Sodium 
Hydroxide. 


Sod'um 
Stearate. 


SNa.OH    =  3Xa.  0.  C18H350 


Sodium 
Hydroxide. 


4Na.OH 


Sodium 
Benzoatc. 


Glycerol. 
(  OH 

(OH 


Erythrol. 

(  OH 

4Na.O.C7H50    +    C4H6  <  ™ 
f  OH 


The  majority  of  saponification  changes  occurring  with  natural 
fixed  oils  and  fats,  £c.,  belong  to  the  third  class  ;  i.e.,  these  sub- 
stances are  chiefly  "  glycerides,"  or  compound  ethers  furnishing 
glycerol  on  saponification  ;  some  liquid  fixed  saponifiable  oils, 
however,  are  of  non-glyceridic  character,  undergoing  saponifica- 
tion changes  of  the  first  kind  ;  thus  sperm  oil  largely  consists  of 
Cetylic  pliysetoleate  and  homologous  substances,  broken  up  by 
saponification,  thus  — 


Cetyl  Physetoleate 

C]6H33.O.CiCH290 


Potassium  Potassium 

Hydroxide.  Physetoleate. 

K.OH  =  K.O.C1GH290 


Cetylic  Alcohol. 

C1CH33.OH 


Most  waxes  possess  an  analogous  constitution;  thus  the  chief 
constituents  of  beeswax  and  spermaceti  are  respectively  myricyl 
palmitate  and  cetyl  palmitate,  decomposable  by  saponification, 
thus — 


Myricyl  Palmitate. 
^3oH(;i  .  0  .  CicH3iO 


Sodium 
Hydroxide. 

Na.OH    =    Na.O.C16H31O 


Sodium 
Palmitate. 


Myricylic 
Alcohol. 

CsoHgi .  OH 


Cetyl  Palmitate. 


Potassium  Potassium 

Hydroxide.  Palmitate. 

K.OH     =     K.O.CJ6H310 


Cetylic 
Alcohol 

C1CH33.OH 


THE    SOURCES    AND    GENERAL    NATURE    OF    OILS,    ETC.  5 

Some  few  vegetable  waxes,  however,  are  of  glyceridic  char- 
acter, e.g.,  Japanese  wax,  chiefly  consisting  of  palmitic  glyceride, 
08H6(O.C16H810)8. 

A  considerable  number  of  oxidised  essential  oils  also  consist 
mainly  of  compound  ethers  of  the  first  class  ;  thus  oil  of  winter- 
green  (Gaultheria  procumbens)  mainly  consists  of  methyl  salicylate, 
and  oil  of  cow  parsnep  (fferacleum  spondylium)  ,of  octyl  acetate  : 
respectively  saponified,  thus — 

Potassium  Potassium  Methylic 

Methyl  Salicylate.  Hydroxide.  Salicylate.  Alcohol. 

CH3.O.C7H502     +     K.OH     =     K.O.CrH502     +     CH3.OH 

Sodium  Sodium  Octylic 

Octyl  Acetite.  Hydroxide.  Acetate.  Alcohol. 

C8HU.O.C2H30     +     Na.OH     =     Na .  0 .  C2H30     +     C8H17.OH 

Compound  ethers  of  Class  II.  (furnishing  dihydric  alcohols  on 
saponification),  although  not  absolutely  unknown  amongst  natural 
products  of  the  oil,  fat,  and  wax  class,  are  very  rare ;  carnauba 

{OTT 
OH 

on  saponification  (p.  18).  Tetrahydric  ethers,  like  those  of 
erythrol,  have  not  as  yet  been  recognised  as  constituents  of  oils 
and  fats,  &c.  ;  and  the  same  remark  applies  to  the  yet  more  com- 
plex pentahydric  and  hexhydric  ethers;  mannitol,  C6H8(OH)6r 
a  hexhydric  alcohol,  has  been  found  as  a  constituent  of  vege- 
table fruits,  &c.,  accompanying  oil — e.g.,  in  unripe  olives ;  but. 
neither  mannitol  nor  any  ethers  thereof  appear  to  be  contained 
in  purified  expressed  olive  oil. 


CLASSIFICATION   OF   OILS,   FATS,   WAXES,   &c., 
ACCORDING   TO   CHEMICAL   COMPOSITION. 

The  following  table  indicates  a  rough  classification  of  the 
principal  varieties  of  oils,  fats,  and  waxes  in  accordance  with 
the  general  chemical  character  of  their  leading  constituents  : — 

DIVISION  I.— HYDROCARBONS. 

1.  Natural  essential  oils,  mostly  of  vegetable  origin. 

2.  Natural  mineral  oils  (petroleum),  including  the  crude  oils,  and  the  pro- 

ducts  thence  obtained  by  distillation,   &c.    (benzoline,  kerosene  oils, 
lubricating  oils,  <fcc.) 

3.  Artificial  products  of  destructive  distillation  (paraffin  oils,   shale  oils, 

bone  oils,  coaltar  oils,  &c.) 

4.  Solid  hydrocarbons  obtainable  from  natural  products  (earthwax,  &c.)  or 

isolated  from  the  two  previous  sources — e.y.,  paraffin  wax  and  allied 
substances  largely  used  in  candle-making. 


6  OILS,    FATS,    WAXES,    ETC. 

DIVISION  II.— CONTAINING  OXYGEN. 

A .  — Saponifiable. 

1.  Essentially  compound  ethers  of  monohydric  alcohols. 

a.  Various  natural  essential  oils  mostly  of  vegetable  origin. 
6.  Certain  animal  fixed  oils,  especially  those  of  cetacean  origin  (some- 
times termed  "  liquid  waxes"). 

c.  Most  animal  and  vegetable  solid  waxes  (waxes  proper). 

d.  Certain  artificial  essential  oils—  t.g.,  various  compound  ethers  used 

for  perfumery  and  flavouring  purposes. 

2.  Essentially  glyceride*,  or  compound  ethers  of  glycerol. 

a.  The  majority  of  animal  and  vegetable  fixed  oils,  fats,  and  butters. 

b.  Some  few  vegetable  waxes. 

JB. — Not  Saponifiable. 

a.  Various  essential  oils,  consisting  of  aldehydes,  ketones,  camphora- 

ceous  bodies,  &c. 
6.  Alcoholiform    constituents   of    natural    animal    and  vegetable  oils 

(cholesterol,  phytosterol,  cetylic  alcohol,  &c.) 

c.  Alcoholiform  bodies  formed  by  fermentation  (fusel  oils). 

d.  Phenoloid  bodies  formed  by  destructive  distillation  and  contained 

in  coaltar,  &c.  (phenol,  cresol,  &c. ) 

e.  Products  formed  by  oxidation  of  hydrocarbons — e.g.,  "  Sanitas  oil'* 

(formed  by  the  atmospheric  oxidation  of  oil  of  turpentine). 

In  the  present  work  a  large  number  of  the  various  substances 
thus  coming  into  the  general  category  of  oils,  fats,  butters,  and 
waxes  are  necessarily  excluded  from  minute  consideration,  fixed 
animal  and  vegetable  oils  and  fats,  &c.,  all  practically  belonging 
to  Division  II.,  Sections  1  and  2.  Certain  hydrocarbons,  how- 
ever, are  intimately  connected  with  the  subjects  dealt  with, 
more  especially  mineral  oils  and  products  of  destructive  distilla- 
tion employed  as  adulterants  of  animal  and  vegetable  fixed  oils, 
-and  as  ingredients  in  lubricating  mixtures,  &c. ;  and  mineral 
waxes  (paraffin  wax,  ozokerite,  and  similar  substances)  employed 
as  candle  materials.  Various  essential  oils,  moreover,  are  in  use 
as  ingredients  in  certain  kinds  of  fancy  (toilet)  soaps  as  perfuming 
agents,  and  in  some  kinds  of  sanitary  soaps  (e.g.,  eucalyptus  oil)  ; 
as  also  are  certain  products  of  destructive  distillation  (e.g.,  car- 
bolic acid  and  its  higher  homologues). 

For  further  classifications  of  fixed  oils,  fats,  waxes,  &c. 
(apart  from  other  kinds  of  oils),  based  either  on  their  physical 
characters  and  the  chemical  nature  of  their  main  ingredients,  or 
on  their  leading  technical  uses,  vide  Chap.  xin. 


SAPONIFICATION    PRODUCTS    OF    OILS,    PATS,    WAXES,    ETC. 


CHAPTER  II. 

SAPONIFICATION  PRODUCTS  OF  OILS,  FATS, 
WAXES,   &c. 

ALCOHOLIFORM  PRODUCTS. 

A  SAPONIFIABLE  oil,  &c.,  as  above  stated,  gives  rise  to  two  pro- 
ducts under  the  influence  of  alkalies  —  viz.,  an  alcoholiform 
organic  substance  (which  in  practice  is  either  glycerol  or  some 
kind  of  monohydric  alcohol),  and  the  alkali  salt  of  an  organic  acid. 
Under  suitable  conditions  (more  especially  heating  under  pres- 
sure in  contact  with  water)  parallel  decompositions  can  be 
brought  about  by  means  of  water,  the  products  of  the  "  hydro- 
lysis "  thus  effected  being  the  alcoholiform  body  and  a  free 
"  fatty  acid."  Thus  in  the  cases  of  the  glyceride  of  oleic  acid  and  of 
cetyl  palmitate  the  hydrolytic  actions  take  place  in  accordance 
with  the  following  equations  : — 

Oleic  Glyceride.  Water.                 Oleic  Acid.                     GHycerol. 

O.C18H330  (OH 

C3H5    O.C18H330  +  3H20  =  3C18H33O.OH  +  C3H5  \  OH 

O.C18H330  (OH 

Cetyl  Palmitate.  Water.  Palmitic  Acid.  Cetylic  Alcohol. 

C1CH33.O.CJ6H310   +  H20  =  CJGH31O.OH     +     C16H33 .  OH 

Similar  reactions  occur  in  many  other  parallel  cases,  the  nature 
of  the  alcoholiform  body  and  of  the  fatty  acid  developed  only 
differing  in  each  instance. 


TRIHYDRIC  ALCOHOLS  FORMED  BY  SAPONI- 
FICATION (GLYCEROL). 

Glycerol,  the  most  frequently  occurring  alcoholiform  saponi- 
fication  product  of  fixed  oils  and  fatty  matters,  solidifies,  when 
pure,  to  a  crystalline  mass  by  long  continued  chilling,*  the  melting 
point  being  about  +  22°  C.;  its  great  hygroscopic  character  renders 
it  extremely  difficult  to  obtain  absolutely  free  from  water,  in 
consequence  of  which  values  varying  from  1*262  to  1*2653  have 

*  Passing  a  few  bubbles  of  chlorine  into  concentrated  glycerol  will  often 
make  it  crystallise  (Werner).  Chilled  glycerol  usually  crystallises  when 
stirred  up  with  a  few  crystals  of  the  previously  solidified  substance,  a 
method  utilised  in  manufacture  (Chap,  xxn.) 


8  OILS,    FATS,    WAXES,    ETC. 

been  stated  as  its  specific  gravity  at  15°.  When  heated  gently 
under  the  ordinary  atmospheric  pressure  it  volatilises  without 
decomposition,  but  at  higher  temperatures  it  splits  up  into  water 
and  acrolein,  thus  — 

Glycerol.  Acrolein. 

C3H803       =       2H20       +       C3H40 

In  vacuo  it  boils  at  about  1  80°  C. 

By  cautious  oxidation  with  alkaline  permanganate  it  yields 
oxalic  acid  in  sufficiently  accurate  proportions  for  quantitative 
estimation.  By  treatment  with  potassium  dichromate  and  sul- 
phuric acid  it  similarly  forms  CO2  and  water;  by  treatment  with 
acetic  anhydride  it  forms  triacetin,  the  saponification  of  which 
furnishes  another  means  of  quantitative  determination  (vide 
Chap,  xxii.)  In  the  absence  of  substances  carbonised  by 
sulphuric  acid,  an  excellent  qualitative  test  is  to  heat  cautiously 
to  120°  or  a  little  higher  a  mixture  of  two  drops  glycerol,  two  of 
fused  phenol,  and  about  as  much  sulphuric  acid  \  a  brown  solid 
mass  forms,  which  after  cooling  dissolves  in  ammonia  with  a 
beautiful  carmine  red  colour  (Reichl)  ;  if  substances  becoming 
carbonised  are  present  they  produce  a  dark  brown  colouring 
matter  which  hides  the  red  tint. 

Polyglycerols.  —  Glycerol  heated  in  contact  with  hydrochloric 
acid  or  certain  other  dehydrating  substances  is  capable  of 
undergoing  reactions  of  dehydration  and  condensation,  expres- 
sible by  the  general  equation  :  — 

nC3H803       =       mH,0       +       C3nH8n_om03u_m. 
Thus  when  n   =    2  and  m    —    1,  diglycerol  results. 


C3H 

2C3H5(OH)3       =       H20       +  10 

C3H5 

l(OH)2 

And  when  n  .=  3  and  m    =    2,  triglycerol  is  produced. 

(OH), 


3C3H6(OH)3       =     2H20       +  C3H5JOH 

r° 

C«H*\(OH)2 

It  has  been  supposed  by  some  chemists  that  bodies  of  this 
class  are  sometimes  contained  in  commercial  "  glycerines,"  more 
especially  those  formed  under  high  pressure  in  autoclaves,  or 
purified  by  distillation;  such  glycerine,  when  slowly  evaporated 
at  a  temperature  of  about  160°  u.,*  leaves  a  non-  volatile  organic 

*  Lewkowitsch,  Year  Boole  of  Pharmacy,  1890,  p.  380. 


ALCOHOLIFORM    PRODUCTS    OF    SAPONIFICATIOX.  9 

residue,  from  the  weight  of  which  (after  deducting  ash)  the 
proportion  of  polyglycerols  present  may  be  deduced.  It  does 
not  appear,  however,  that  the  residue  thus  left  has  been  definitely 
proved  to  have  the  character  and  composition  assigned  to  it, 
although  the  formation  of  polyglycerols  is,  a  priori,  highly  pro- 
bable. 

Natural  Triglycerides. — As  a  very  general,  if  not  abso- 
lutely invariable,  rule,  only  one  acid  radicle  is  contained  in  any 
given  substance — i.e.,  substances  of  the  types 

CH2  .  OR  CH2  .  OR  CH2  .  OR 

CH   .  OR  CH   .OS  CH  .  OS 

CH2  .  OS  CH2  .  OR  CH2  .  OT 

(where  K,  S,  and  T  are  not  the  same)  are  only  extremely  rarely- 
met  with.  Cow's  butter,  however,  not  improbably  contains  a 
mixed  glyceride  of  one  or  other  of  these  classes ;  for  whilst  it 
forms  butyric  acid  on  saponification,  no  butyrin  (tri glyceride  of 
butyric  acid)  can  be  dissolved  out  from  it  by  means  of  alcohol ; 
whereas  mixtures  of  butyrin  and  other  triglycerides  readily 
yield  the  former  to  that  solvent ;  hence  a  mixed  glyceride,, 
oleo  palmito  butyric  glyceride^ 

CH2.O.C]8H330 

CH    .  0  .  C1CH310 
I 
CH2  .  0  .  C4H70 

(or  some  analogous  substance)  has  been  supposed  to  be  present, 
breaking  up  on  saponification  into  glycerol,  with  formation  of 
salts  of  oleic,  palmitic,  and  butyric  acids. 

Some  few  other  fats  have  been  supposed,  on  similar  grounds,  to 
contain  analogous  mixed  glycerides ;  but,  as  a  general  rule,  when- 
ever an  oil  or  fat  yields  on  saponification  the  salts  of  two  or  more 
different  fatty  acids,  it  can  be  shown  that  the  original  substance 
is  a  mixture  of  two  or  more  triglycerides  of  the  ordinary  type- 
(i.e.,  each  containing  only  one  acid  radicle) ;  thus,  by  chilling  an 
oil  yielding  palmitic  and  oleic  acids  on  saponification,  a  solid  fat 
usually  separates,  yielding  only  palmitic  acid  on  saponification  ; 
whilst  the  liquid  portion  is  substantially  olein,  giving  rise  to 
oleic  acid  only  on  similar  treatment,  the  reaction  in  each  case 
being  indicated  by  the  general  equation  : — 

Normal  Caustic  P,,     _  _,  Potassium 

Triglyceride.  Potash.  Salt 

CH2  .  OR  CHo .  OH 

I  I 

CH  .  OR  +  3K .  OH  =  CH  .OH  +  3K .  OR 

CH2  .  OR  CH3  .  OH 


10 


OILS,    FATS,    WAXES,    ETC. 


the  effect  of  the  alkali  being  always  the  same,  the  only  differences 
in  different  cases  being  due  to  the  variation  in  the  nature  of  R. 

Hydrolysis  of  Glycerides. — As  a  general  rule,  pure  triglyce- 
rides  are  acted  upon  by  water  only  at  an  elevated  temperature, 
treatment  with  superheated  steam  blown  through  the  mass,  or 
digestion  with  water  under  considerable  pressure  being  requisite; 
under  such  circumstances,  the  glycerol  set  free  is  often  more  or 
less  decomposed  by  secondary  reactions.  With  crude  unpurified 
oils  continued  standing  at  the  ordinary  temperature  often  suffices, 
the  action  in  such  cases  being  largely  due  to  changes  of  a  fermen- 
tative character  taking  place  in  the  mucilaginous  or  albuminous 
extractive  matters  present  as  impurities ;  in  extreme  cases  the 
action  goes  on  to  such  an  extent  as  to  hydrolyse  the  larger 
portion  of  the  glycerides  present,  so  that  upwards  of  50  per  cent, 
of  the  mass  is  free  fatty  acid.  Changes  of  this  description  are 
almost  invariably  accompanied  by  the  production  of  bye-products 
of  unpleasant  taste  and  smell,  so  that  the  development  of  "  ran- 
cidity "  by  this  action  greatly  deteriorates  the  value  of  the  oil, 
<fec.,  for  many  purposes,  more  especially  culinary  and  edible  ones. 

In  all  probability  the  formation  of  a  free  fatty  acid  and  glycerol 
from  a  glyceride  by  hydrolytic  action  takes  place  in  three  stages, 
giving  rise  to  two  kinds  of  intermediate  products,  diglycerides 
.and  monoglycerides  respectively ;  thus,  it'  R  be  a  fatty  acid 
radicle — 


Normnl 
Triglyceride. 

OH2 .  OR 
CH  .  OR      + 
CH2  .  OR 

Dislyceride. 

CH2 .  OR 

I 
CH  .OR  + 

I 

CH.> .  OH 


Waier. 


HoO      = 


Fatty 
D'uzlyceride. 

CH2.OR 

CH  .OR 

I 

CH2 .  OH 


Fatty  Acid. 

H.OR 


Water.  Monoglyceride.  Fatty  Acid. 

CH2.  OR 

H,,0      =      CH  .OH      +      H .  OR 
CHo.OH 


Monojjlyceride. 

CH3.OR 

CH .OH      + 
I 
CHo.OH 


"Water. 


H20 


Glycerol. 

CHo .  OH 


Fatty  Acid. 


H .  OR 


=      CH  .OH 
CH2 .  OH 
The  final  action  may  consequently  be  expressed  by  the  equation- 


Triglyceride. 
CHo. OR 
CH  .OR 
CHo.  OR 


Water. 
3H20      = 


Glycerol. 
CH2.OH 
CH  .OH 
CHo  .  OH 


Fatty  Acid. 

3  H.OR 


ALCOHOLIFORM    PRODUCTS    OF    SAPONIFICATION.  11 

which  may  be  written  somewhat  more  compactly  — 

+   3H-OR 


The  formation  of  the  intermediate  substances  by  gradual 
hydrolysis  has  not  been  much  studied  as  yet  ;  in  the  case  of 
rape  oil,  however,  it  has  been  shown  that  whilst  fresh  oil  con- 
tains the  triglyceride  erucin, 


(C22H410)3 
the  corresponding  diglyceride  dierucin, 

CTT  \  /~^TT  /^\        r^       TT       /"\ 

3-T15  J  l_y±lo  .   U  .   v^2l>^Ml^' 

(C22H410).,  [  03       =       CH    .  0  .  Co2H410 
"  H  I  CH2  .  0  .  H 

is  sometimes  contained  in  old  oil,*  probably  formed  as  above  by 
partial  hydrolysis.  On  the  other  hand,  the  reverse  reactions 
leading  to  the  successive  building  up  from  glycerol  of  mono- 
glyceride,  diglyceride,  and  triglyceride  are  well  known  laboratory 
operations  :  thus — 

Glycerol.  Fatty  Acid.          Monoglycf-ride. 

(  OH  I  OR 

C3TlJOH     -l-    H.OR    =     CSH5     OH     +     H,O 
(OH  (OH 

Monoglycfride.  Diglyceride. 

( OR  ( OR 

C3H5  \  OH  +    H .  OR    =     C3Hn  {  OR     +     H,0 

(OH  (OH 

Diglycsride.  Triglyceride. 

( OR  ( OR 

CoH5    OR     +    H.OR    =     C3H5    OR     +     H20 
(OH  (OR 

In  many  cases,  when  it  is  desired  to  obtain  triglycerides  in  a 
state  of  purity,  it  is  more  easy  to  saponify  an  oil,  separate  and 
purify  the  resulting  fatty  acids,  and  convert  them  into  glycerides 
in  this  way  than  it  is  to  separate  the  original  glycerides  them- 
selves contained  in  the  oil. 

The  following  boiling  and  melting  points  are  possessed  by 
some  pure  triglycerides  prepared  synthetically  in  this  way  : — 

Melting  Poiut.        Boiling  Point. 
Butyrin,    .         .  C3H5(0 .  C4H70)3  Fluid  285° 


Laurin, 
Myristin,  . 
Palmitiii,  . 
Stearin, 
Olein, 


C3Hs(0 .  Ci2H230)3  45° 


C3H5(O.C14H270)3  55 

C3H5(O.C1CH310)3  62 

C3H5(0  .  C18H350)3  71-5 

C3H5(0  .  C18H330)3  solidifies  at  -  6° 


*Reimerand  Will(Berichte  der Deut.  Chem.  Ges.,  1886,  xix.,  p.  3320)  found, 
that  a  deposit  which  had  slowly  formed  in  a  quantity  of  colza  oil  was  not 
the  triglyceride  usually  obtained  tinder  such  conditions,  but  the  diglyceride 
melting  at  47°. 


12  OILS,    FATS,    WAXES,    ETC. 

When  oils  that  have  become  hydrolysed  through  rancidity  are 
refined  by  treatment  with  alkalies  (Chap.  XL),  the  free  acids  are 
removed  and  neutral  oils  left ;  but  other  kinds  of  refining  pro- 
cesses do  not  affect  the  free  acids,  which  accordingly  are  apt  to 
be  found  in  commercial  oils  to  varying  extents,  sometimes  only 
inconsiderable  amounts,  and  sometimes  very  large  percentages 
being  present.  According  to  Thum  the  free  acids  do  not  consist 
solely  of  oleic  acid,  as  is  often  supposed,  but  of  a  mixture  in 
exactly  the  same  proportions  as  that  in  which  they  exist  in  the 
undecomposed  glycerides.  Thus  palm  oil  and  olive  kernel  oil 
containing  much  free  acid  yield  as  much  solid  free  acids  relatively 
to  oleic  acid  when  the  free  acids  are  removed  by  agitation  with 
a  cold  alkaline  ley,  as  are  yielded  by  the  neutral  unsaponified 
fats  present. 

Just  as  the  glyceridic  compound  ethers  of  fatty  acids  are  apt 
to  be  hydrolysed  under  appropriate  conditions,  so  are  their 
alkaline  salts  (soaps)  split  up  by  water  with  the  formation  of 
basic  substance  (free  alkali)  and  an  acid  salt  (vide  p.  23). 

It  is  a  remarkable  fact  that  although  a  somewhat  considerable 
number  of  monohydric  alcohols  are  known  to  be  formed  by  the 
saponification  of  fixed  oils,  essential  oils,  and  similar  sub- 
stances, only  one  trihydric  alcohol,  viz.,  glycerol,  has  ever  been 
found  to  be  produced  from  such  sources. 

Isoglyceride  Theory. — Theoretically  the  existence  is  possible 
of  various  substances  possessing  the  composition  of  a  trihy- 
droxylated  propane,  C3H5(OH)3,  but  not  identical  with  glycerol  : 
these  substances  would  naturally  form  compound  ethers  isomeric 
with  ordinary  glycerides  containing  the  same  acid  radicles. 
Amongst  such  hypothetical  bodies,  the  compound  ethers  of  ortho- 
propionic  acid,  indicated  by  the  general  formula — 

(  OR 

C  ]  OR  (JH., .  OR 

|  /OR  | 

CH,        isomeric  with  CM   .  OR 

!    '  I 

CH,  CH2.01l 

have  been  supposed  by  some  chemists  to  be  present  in  certain 
fatty  matters,  notably  cow's  butter  ;  but  the  experimental  proofs 
of  this  supposition  are  singularly  wanting  in  clearness  and 
cogency.  Such  compound  ethers  on  saponification  should  neu- 
tralise four  instead  of  three  equivalents  of  alkali,  generating  an 
alkaline  propionate  instead  of  glycerol ;  thus — 

Hypothetical  Sodium 

Isogyceride.  Hydroxide.  Sodium  Propionate.  Sodium  Salt.        Water. 

C2H5.C(OR)3     +    4NaOH    =    C,H3  .  CO  .  ONa    +    3NaOR    +    2H2O 


ALCOHOLIFORM    PRODUCTS    OF    SAPONIFICATION.  13 

MONOHYDRIC  ALCOHOLS  FORMED  BY 
SAPONIFICATION. 

Numerous  families  of  alcohols  (monohydroxylated  hydro- 
carbons) are  known  to  the  chemist,  derived  successively  from 
saturated  hydrocarbons  of  the  series  Cn  H2n + 2,  and  from  the  other 
series  of  hydrocarbons  containing  less  hydrogen,  by  the  replace- 
ment of  hydrogen  by  hydroxyl :  thus  inter  alia  the  following 
families  of  alcohols  are  known  : — 

Ethylic  alcohol  homologues ;  general  formula,  Cu  H-n+i  .  OH 
Allylic       „  ,,  „  „         CaHo^.OH 

Phenol  ,,  ,,  „         CnH»n-7.0H 

Cinnamic  alcohol    .,  „  ,,         CnH2n-9,OH 

Although  representatives  of  several  such  families  of  alcohols 
are  found  amongst  products  of  destructive  distillation  (coaltar 
oils,  £c.),  and  in  essential  oils  and  the  allied  balsams  and  other 
aromatic  bodies,  and  in  small  quantities  as  natural  constituents 
of  fixed  oils  of  various  kinds  (occurring  there  in  the  free  state), 
yet  compound  ethers  derived  from  alcohols  of  the  first  and  second 
of  the  above  families  appear  to  be  the  only  kinds  naturally 
occurring  in  fixed  oils  and  waxes,  etc.  ;  and  of  these  by  far  the 
most  frequently  occurring  substances  belong  to  the  first  class. 

Ethylic  Series  of  Alcohols. — The  table  on  next  page  indicates 
the  leading  alcohols  of  this  family  (general  formula  CnH2n  +  i  .  OH) 
derived  from  fixed  and  essential  oils  and  similar  sources  ;  besides 
those  mentioned  numerous  isomeric  modifications  of  many  of 
them  exist,  obtainable  artificially  by  laboratory  reactions. 

The  higher  alcohols  of  this  series,  when  fused  with  alkalies, 
evolve  hydrogen  with  formation  of  the  alkali  salt  of  the  corre- 
sponding fatty  acid;*  thus — 

CVtylic  Alcohol.  Potassium  Palmitate. 

C15H31.CH2.OH    +    KOH    =    C15H31.CO.OK    +    2H2 

Myricylic  Alcohol.  Potassium  Melissate. 

C29H59.CH2.OH    +    KOH    =    C29H59  .  CO  .  OK    -f    2H2 

They  are  readily  converted  into  compound  ethers  by  treatment 
with  organic  anhydrides  (e.g.,  acetic  anhydride),  and  in  some 
cases  by  heating  with  the  acids  alone,  water  being  evolved. 

*  C.  Hell  (Liebig's  Annalen,  pp.  223,  269)  has  based  a  method  for  the  quan- 
titative determination  of  higher  alcohols  on  this  reaction,  the  substance  to 
be  examined  being  heated  to  300°-310°  in  contact  with  soda  lime,  and  the 
evolved  hydrogen  collected  and  measured.  At  higher  temperatures  there 
is  a  possibility  of  hydrogen  being  also  evolved  by  the  action  of  caustic 
alkalies  on  oleic  acid  (p.  24).  This  method  has  been  found  useful  in  the 
examination  of  beeswax  which,  when  genuine,  furnishes  about  54  per 
cent,  of  myricylic  alcohol. 


14 


OILS,    FATS,    WAXES,    ETC. 


Name. 

Formula. 

Boil  ing  Point. 

Melting 
Point. 

Sources. 

Methylic  alcohol, 

CH3  .  OH 

cc°c. 

... 

Saponification  of  oil  of  winter- 

green  ;     wood    distillation 

products. 

Ethylic  alcohol, 

C2H5  .  OH 

78° 

Fermentation  of  saccharine 

matter. 

Propylic  alcohol,  ) 

97° 

Fermentation  fusel  oils. 

Isopropylic  alco-  ' 
hoi,                        ) 

C3H7  .  OH 

84° 

Isopropylic  iodide  from  gly- 
cerol  and  hydriodic  acid. 

Normal   Butylic   j 

117° 

... 

Heavy  oils  from  brandy. 

alcohol, 

C4H9.  OH 

Isobutylic  alcohol  ) 
Amylic  alcohols 

dHn.OH 

107° 
127°-13S° 

... 

Potato  and  beet  fusel  oils. 
Fusel  oils  from  grain  spirit, 

(several  isomeric  ! 

&c.     Saponification  of   oil 

modifications), 

of  Roman  Chamomile. 

Hexylic  alcohols 

CCH13.OH 

147°-157° 

Sapouification  of  oil  of  cow's 

(several  modi- 

parsley, oil  of  Roman  Cha- 

fications), 

momile,  &c. 

Normal  Primary          C  7  Hj  3  .  OH 

176° 

Brandy   fusel    oils.     Hydro- 

Heptylic alcohol, 

genation  of  ccnaiithol  from 

castor  oil. 

Octylic  alcohols, 

C8H]7.OH 

180°-  192° 

Saponification  of  oil  of  Hera- 

deum  spondylium  and  H. 

giganteum.    Action  of  hot 

alkali  on  castor  oil. 

Nonylic  alcohols, 

C9H19.OH 

... 

. 

Normal  Primary 

C10H21.OH, 

119°  at  15 

7°C. 

Hydrogenation      of      capric 

Decy  lie  alcohol, 

millims. 

aldehyde. 

pressure. 

Secondary  Hen- 

CnH23.OH 

220° 

... 

Hydrogenation  of  oil  of  rue. 

decylic  alcohol, 

Dodecylic  alcohols,   C12H25.OH 

143°  at  15 

24° 

Hydrogenation     of     lauric 

millims. 

aldehyde. 

Tridecylic  alcohols, 

C13H27.OH 

pressure. 

19° 

Saponification  of  sperm  oil. 

Normal  Primary 

CJ4H29.OH 

167°  at  15 

38° 

Hydrogenation    of  myristic 

Tetradecylic 

millims. 

aldehyde. 

alcohol, 

pressure. 

Pentadecylic  alco-     C15HC1.OH 

... 

... 

hols, 

Normal  Primary  \ 

lS9°'5atl5 

49°'5 

Hydrogenation     of    palmitic 

Hexadecylic  al-  ' 

C.^Ho*  OH 

millims. 

aldehyde. 

cohol,                    ( 

^1  6^*33  •  vJi 

pressure. 

Cetylic  alcohol,     ) 

188°-  193° 

49°  '2 

Saponification  of  spermaceti. 

at  15mm. 

... 

pressure. 

Heptadecylic  al- 

c]7HC;.OH 

... 

... 

cohols, 

Normal  Primary 

C18H37.OH 

2  10°  -5  at 

59° 

Hydrogenation     of     stearic 

Octodecylic  al- 

15millims. 

aldehyde.      Saponification 

cohol, 

pressure. 

of    spermaceti    (in    small 

quantity). 

Cerylic  alcohol,     \ 
Isocerylic  alcohol,  J 

C27H55.OH 

...    \ 

79° 
62° 

(  Chinese  wax. 
<  Carnauba  wax. 
(  Wax  of  Fkus  gummiflua. 

Myricylic  alcohol,  ) 

, 

81!0 

-p 

xSeeswax. 

Isomyricylic  alco-  > 
hoi  ?                       \ 

CSOH61.OH 

...    ( 

oO 

72° 

Carnauba  wax. 

ALCOIIOLIFORM    PRODUCTS    OF    SAPONIFICATIOX.  15 

Acetic 
Cetylic  Alcohol.  Anhydride.  Cetyl  Acetate.  Acetic  Acid. 

C]6H33.OH    +    (C2H30)20    =    C]0H33.O.CoH30    +    C2H3O.OH 

Cetylic  Alcohol.  Acetic  Acid.  Cetyl  Acetate.  Water. 

C16H33.OH    +    C2H3O.OH    =    C1GH33.O.C2H30    +    H20 

The  compound  ethers  thus  produced  are,  in  turn,  readily 
saponified  by  alcoholic  potash,  and  from  the  amount  of  potash 
neutralised  during  the  operation  the  molecular  weight  of  the 
alcohol  is  deducible,  due  corrections  being  made  for  unsaponifi- 
able  matters,  &c.,  if  present  (Chap,  viu.) 

Allylic  Series  of  Alcohols. — Alcohols  of  the  series 
CnHgn.j.OH,  derived  from  the  olefine  family  of  hydrocarbons 
of  formula  CnH9n,  are  only  sparsely  represented  amongst  the 
derivatives  from  natural  products.  Acrolein  (acrylic  aldehyde), 
C2H3.  CHO,  by  hydrogenation  yields  allylic  alcohol,  C2H3.CH2.OH 
(also  obtainable  in  various  other  ways),  existing  as  a  thiocyanic 
ether  in  the  oils  of  black  mustard  seed,  horse  radish,  and  garlic  ; 
whilst  higher  homologues  are  probably  contained  amongst  the 
alcohols  of  the  previous  series  obtained  on  saponifying  sperm 
oil,  since  in  certain  cases  a  deficiency  of  hydrogen  is  observed 
on  analysis,  coupled  with  a  strongly  marked  tendency  to  com- 
bine directly  with  iodine,  indicating  the  presence  of  unsaturated 
compounds.  These  higher  alcohols,  however,  have  not  as  yet 
been  isolated  from  the  other  bodies  accompanying  them  in  a 
state  of  sufficient  purity  to  admit  of  their  formulae  being  exactly 
determined.  Borneol,  C10H19 .  OH,  occurs  in  the  camphor  of 
Dryobalanops  camphora,  and  to  a  small  extent  in  oil  of  valerian 
and  oil  of  rosemary. 

Alcohols  of  the  series  CnH2n_3.  OH,  derived  from  the  CnH2n_2. 
(acetylene)  series  of  hydrocarbons,  are  found  to  some  extent  in 
certain  essential  oils — e.g.,  geraniol,  C10Hllr .OH,  in  Indian  gera- 
nium oil.  This  appears  to  be  a  true  analogue  of  ethylic  and 
allylic  alcohols,  being  capable  of  yielding  by  oxidation  an  alde- 
hyde and  a  monobasic  acid  (geranic  acid)  C9H15 .  COH  and 
C9H15 .  CO .  OH  respectively  :  no  substances  of  analogous  char- 
acter have  as  yet  been  isolated  from  fixed  oils  and  fats,  tfcc. 

Phenol  and  its  Homologues. — Alcohols  derived  from  hydro- 
carbons still  poorer  in  hydrogen  are  occasionally  met  with  as 
constituents  of  natural  products  of  the  resinous  class,  or  as  sub- 
stances formed  by  destructive  distillation;  thus  the  hydrocar- 
bons of  the  benzene  family,  CnH2n_6,  give  rise  to  two  such  classes 
of  alcohols,  both  indicated  by  the  general  formula  CuH:n_7.OH 
and  derived  from  the  same  parent  body,  phenol,  CGH5 .  OH.  In 
the  one  class  (phenols  proper)  the  hydroxyl  group  is  situated  in 
connection  with  the  "  benzene  nucleus  "  of  6  carbon  atoms  ;  and 
in  the  other  (benzylic  alcohol  series]  the  hydroxyl  group  is  not 
situated  in  the  benzene  radicle,  but  in  one  of  the  "side  chains  " 


16  OILS,    FATS,    WAXES,    ETC. 

introduced  by  the   methylation   of  benzene   so   as  to   develop 
homologous  hydrocarbons  ;  thus  — 

Phenols. 

Phenol  (carbolic  acid),          .        .         .     C6H5  .  OH 
Cresol  (methyl  phenol),          .         .         .     CCH4/^3 

(  CH3 

Xylenol  (dimethyl  phenol),  .         .     CCH3  {  CH3 


OH 

Phlorol  (ethyl  phenol),  .         .         .     CGH4     £|p 

Benzylic  Alcohol  Series. 

Benzylic  alcohol,  ....  CGH5.CH2.OH 

Xylylic  alcohol,     .....  C«H*{cH2    OH 

Benzyl  carbinol,   .....  C6H5  .  CH22/CH2  .  OH 

Alcohols  of  the  phenol  class  are  mostly  contained  in  the  tars 
derived  from  the  destructive  distillation  of  coal,  wood,  &c.  : 
benzylic  alcohol  is  contained  as  such  in  the  volatile  oil  of  cherry 
laurel,  and  in  the  form  of  a  compound  ether  in  Balsam  of  Peru 
and  Liquid  Storax  ;  a  higher  homologue,  sycocerylic  alcoJwl, 
C18H29  .  OH,  is  similarly  found  as  an  acetic  compound  ether  in 
the  resin  of  Ficus  rubiginosa  :  a-lactucerol  and  (3-lactucerol'  are 
two  isomerides  thereof  contained  as  acetic  ethers  in  lettuce  juice. 
Quebrachol  (from  Quebracho  bark),  and  cupreol  and  cinchol 
(from  Cinchona  barks)  are  analogous  substances  isomeric  with 
one  another  and  indicated  by  the  higher  homologous  formula, 
C20H33  .  OH  ;  whilst  Pliasol  (from  Phaseolus  vulgaris)  is  a  lower 
homologue,  C]5  H23  .  OH.  All  these  substances  are  closely  akin 
to  cholesterol,  isocJiolesterol,  phytosterol  and  paraphytosterol,  alco- 
holiform  substances  belonging  to  the  family  derived  from  the 
hydrocarbons,  CnH2n_8,  and  occurring  in  various  fixed  oils  as 
normal  constituents  dissolved  in  the  glycerides,  <fcc.,  constituting 
the  bulk  of  the  oils.  It  is  extremely  probable  that  other 
.analogous  substances  are  also  similarly  contained  in  oils,  <fec., 
but  as  yet  this  has  not  been  demonstrated  to  be  the  case.  In 
the  husks  of  PJiaseolus  vulgaris  both  paraphytosterol  and  phasol 
are  present  ;  when  such  substances  occur  in  the  vicinity  of  oil- 
containing  tissues,  obviously  any  process  applicable  for  the  ex- 
traction of  the  oil  is  extremely  likely  to  dissolve  out  more  or 
less  of  the  accompanying  alcoholiform  substances,  as  well  as  any 
other  substances  soluble  in  oil  that  may  happen  to  be  contained 
in  the  seeds,  <fcc.,  operated  upon. 

Cholesterol  Series  and  Analogues.  —  Cholesterol  and  its 
isomerides  appear  to  be  homologues  of  cinnamic  alco/iol,  C9H9.OH 
(contained  in  storax  as  cinnamic  ether),  indicated  by  the  formula 
C9(5H43  .  OH  ;  some  (cholesterol  —  long  known  as  a  bile  constituent 


ALCOHOLIFORM   PRODUCTS   OF  SAPONIFICATION.  17 

— and  isocholesterol)  chiefly  occur  in  oils,  &c.,  of  animal  origin, 
such  as  whale  and  fish  oils  and  woolgrease ;  others  (phytosterol 
and  isophytosterol)  are  similarly  found  in  vegetable  oils,  such  as 
olive  oil.  Ambergris  and  castoreum  (from  the  Castor  beaver) 
also  appear  to  contain  related  substances  (ambreol  and  castorol 
respectively).  All  these  bodies,  like  the  sycocerylic  alcohol  and 
its  homologues  above  mentioned,  are  of  alcoholiform  character 
readily  yielding  acetic  and  benzoic  compound  ethers  (often  of 
highly  crystalline  character,  and  readily  purified  in  consequence), 
the  melting  points  of  which  are  characteristic.  Thus,  cholesterol 
heated  with  benzoic  anhydride  (preferably  in  a  sealed  tube  at 
200°)  forms  a  compound  ether  almost  insoluble  in  boiling  alcohol, 
but^  crystallisable  from  ether  in  right-angled  tables,  melting  at 
150°-151  °.  The  following  table  illustrates  some  of  the  differences 
between  cholesterol  and  its  isomerides  : — 


Melting  Point. 

Action  on  Polarised 
Light. 

Melting  Point  of 
Benzoic  Ether. 

Cholesterol,  .  . 
Isocholesterol,  . 
Phytosterol,  . 

147° 
137°-  138° 
132°-  133° 

Lsevogyrate. 
Dextrogyrate. 
Lsevogyrate. 

150°-151° 
190°-191° 

Paraphytosterol, 

149°-  150° 

Dextrogyrate. 



When  dissolved  in  chloroform  and  treated  with  an  equal 
volume  of  sulphuric  acid,  cholesterol  yields  a  blood  red  colora- 
tion, soon  becoming  cherry  red  and  purplish,  permanent  for 
several  days ;  the  acid  underlying  the  chloroform  solution  ex- 
hibits a  strong  green  fluorescence.  Phytosterol  gives  a  similar 
coloration,  becoming  a  bluish  red  on  standing  some  days  ;  whilst 
isocholesterol  gives  no  colour  at  all.  On  treatment  with  acetic 
anhydride,  compound  ethers  are  produced  in  each  case,  the 
"acetyl  number"  of  which  is  135-5  (parts  of  caustic  potash, 
KOH,  neutralised  by  the  acetic  acid  developed  by  the  saponifica- 
tion  of  1,000  parts  of  compound  ether,  Chap,  vin.);  the  corre- 
sponding values  for  the  similar  compound  ethers  obtained 
from  cetylic,  cerylic,  and  myricylic  alcohols  being  respectively 
197-5,  128-1,  and  116-7. 

Another  substance  closely  akin  to  phytosterol  has  been  isolated 
from  the  seeds  of  Lupinus  luteus,  i.e.,  lupeol*  probably  indicated 
by  the  formula  C26H42O,  containing  less  hydrogen  than  phyto- 
sterol ;  this  melts  at  204°,  is  dextrorotatory,  and  forms  benzoic 
and  acetic  ethers  melting  respectively  at  250°  and  230° ;  dissolved 
in  chloroform  and  treated  with  acetic  anhydride  and  sulphuric 
acid,  it  gives  a  reddish  coloration,  becoming  intensely  violet  red 
on  standing.  Several  other  substances  of  analogous  character 
appear  to  be  contained  in  various  vegetable  products — e.g.,  hydro- 

*  Likternik,  Berich'.e  Deut.  Chem.  Ge».t  1891,  xxiv.,  pp.  183  and  187. 

2 


18  OILS,    FATS,    WAXES,    ETC. 

carotin  (carrots),  paracJwlesterol  (E  'thulium  septicum),  &c.,  &c.  ; 
but  their  occurrence  in  oil-bearing  seeds,  and  the  oils  thence 
obtainable,  has  not  yet  been  substantiated. 

GLYCOLS. 

It  has  been  shown  by  Stiirke  *  that  when  carnauba  wax  is 
saponified,  and  the  alcoholiform  constituents  thus  set  free  frac- 
tionated by  means  of  petroleum,  a  glycol  is  obtained  melting  at 
103  '5  to  103-8,  and  giving  numbers  on  analysis  agreeing  with 

(  OI-T      OTT 
the  formula  C25H52O2,  or  C23H46  <  ^-g2  '  Q-^;  this  product  evolves. 


eight  hydrogen  atoms  on  fusion  with  caustic  alkalies,  forming 
an  acid  of  the  oxalic  series,  thus  — 

(CH9.OH         ~  ,TT  TT     fCO.ONa 

H 


2346        CHj.  OH  2  2346       CO  .  ONa 

just  as  cerylic  alcohol  and  similar  bodies  evolve  four  hydrogen 
atoms  (p.  13),  forming  an  acid  of  the  stearic  series,  thus  — 

C26H53  .  CH2  .  OH  +  NaOH  =  2H2  +  C26H53  .  CO  .  ONa. 


CHAPTER  III.1J 

SAPONIFICATION   PRODUCTS   OF   OILS,   FATS, 
WAXES,   &c. 

FATTY  ACIDS. 

IT  is  a  remarkable  fact  that  all  known  compound  ethers  con- 
tained in  natural  fixed  oils  and  fats,  &c.,  invariably  give  rise  on 
saponification  to  monobasic  acids  only,  dibasic  acids  (like  oxalic 
acid),  and  acids  of  still  higher  basicity  being  conspicuous  by  their 
absence  from  the  products  thus  formed,  although  in  many  cases 
readily  obtainable  from  these  products  by  simple  operations  in 
the  laboratory. 

At  least  six  different  families  of  monobasic  acids  are  repre- 
sented amongst  the  saponification  products  of  fixed  oils,  <fcc.,  four 
of  which  are  included  in  the  general  formula,  CmH2n  +1 .  CO  .  OH; 
according  as  in  =  n,  or  =  n  +  1,  n  +  2,  or  11  +  3,  this  general 
formula  represents  the  following  families  : — 


Formula  of  Acid. 

CmH2m  +  1.CO.OH 
CmH2m  -  j  .  CO  .  OH 
CmH2m  _  3  •  CO  .  OH 
CmH2m.5.CO.OH 


Family. 

Acetic  (or  stearic)  series. 
Acrylic  (or  oleic)  series. 
Propiolic  (or  linolic)  series. 
Linolenic  series. 


*  Annalen  der  Chemie,  pp.  223-2S3  ;  also  in  abstract,  Journal  Soc.  Chem. 
Industry,  1884,  p.  448. 


FATTY    ACIDS. 


19 


Two  other  families  are  more  highly  oxidised,  being  included  in 

(  OTT 

the  general  formula  CmII0ll  -j  p..       OH>  accor^ing  as  ni  =  n  or 

—  n  +  1  the  following  two  families  result : — 


CmH 


Formula  of  Acid. 
I  OH. 

CO  .  OH. 


CmH 


2m   -    2 


fOH. 
CO .  OH. 


I  Family. 

Oxyacetic(oxystearic  or  glycollic) 

series. 
Ox3*acrylic  (oxyoleic  or  ricinoleic) 

series. 


In  addition  to  these  six  leading  families  of  monobasic  acids,  re- 
presentatives of  several  others  are  obtainable  by  saponification 
from  various  essential  oils  and  allied  products  ;  whilst  by  gentle 
oxidation  processes  or  other  reactions  several  different  kinds  of 
more  oxidised  monobasic  acids  are  readily  formed  from  the 
normal  "fatty  acids"  derived  from  natural  fixed  oils,  &c.  Thus 
for  example : — 


Formula  of  Acid.                              Family. 

Examples  and  Sonrces. 

(  Benzoic  and  toluic  acids,  &c.  ; 

OmH2m  _  7  .  CO  .  OH 

Benzoic  series 

)    from  gum  benzoin,  balsam  of 
j    Tolu,  dragon's  blood,  storax, 

(    oil  of  bitter  almonds,  &c. 

!  Cinnamic  acid  ;   from   oil  -of 

CmH2m  -  9  •   CO  .  OH     Cinnamic  series 

cinnamon,     cassia,     storax, 

balsam  of  Tolu,  &c. 

r  TT           /OH 
wn2m  -  8  -[cO.OH 

Oxybenzoic  (salicylic) 
series 

f  Salicylic   acid  ;     from    gaul- 
\   theria  oil,  &c. 

(OH 
CmH2m  .  !  \  OH 

Glyceric  (dioxystearic) 

(  Oxidation  of  oleic  acid  and 
<    isomerides  and  homologues 

(CO,  OH 

series 

f    thereof. 

r  H            /(OH)S 

L^ttsm  -  2  |  QQ  <  QH 

Erythroglucic       (tri- 
oxystearic)  series 

i  CigH3(505  ;  from  oxidation  of 
<    ricinoleic  acid  and  its  iso- 
/    merides. 

c  H             f(OH)4 

Tetroxystearic  series 

(  CigHsgOe  (sativic  acid)  ;  from 
\   oxidation  of  liiiolic  acid. 

CmH2m  _  5  |  c^oH     Hexoxystearic  series 

(  CigH3608  (linusic  acid)  ;  from 
(    oxidation  of  linolenic  acid. 

ACETIC  FAMILY  OF  FATTY  ACIDS. 

The  following  table  denotes  the  leading  acids  of  the  acetic 
family  (general  formula  CnH2nO2  -  CmH2m  +1 .  CO .  OH)  derived 
from  fixed  oils,  waxes,  essential  oils,  and  similar  sources  :  in 
addition  numerous  isomeric  modifications  of  many  of  the  acids 
are  known,  obtained  artificially  by  synthetic  and  other  laboratory 
operations  : — 


20 


OILS,    FATS,    WAXES,    ETC. 


Formula. 

Name  of  Acid. 

Boiling 
Point. 

Melting 
Point. 

Source  •». 

CH202 

Formic, 

ioi°c 

8°C 

Ants  ;  nettles. 

C2H402 

Acetic,                       118° 

17° 

Acetous  fermentation  ;  oil 

of    cow  parsnep,    and 

various  other  essential 

oils. 

C3H602 

Propionic     or  ;      140° 

... 

Oxidation     of     propylic 

Tritylic, 

alcohol    from    fermen- 

tated  fusel  oil. 

C4H802         Normal  Butyric, 

162° 

—  3° 

Cow's  butter  ;    perspira- 

Isobutyric, 

153° 

tion  ;  oil  of  cow  parsnep. 
Oxidation    of    isobutylic 

alcohol  from  fusel  oil  ; 

Roman  chamomile  oil. 

CsHioOjj 

Valeric  or  Pen- 

175°-  185° 

... 

Several  isomerides  known. 

toic, 

Valerian  root  ;    Isova- 

leric  acid  from   fat  of 

Delphinum  Phoccena. 

C6H12O2 

Caproic      or        200° 

-  9°        ;  Isohexoic  acid  (isobutyl- 

Hexoic, 

acetic  acid)  from  cow's 

butter     and    cokernut 

oil. 

205° 

-  1°'5 

Normal   hexoic  acid,   as 

octylic  ether  in  oil  of 

Heracleum. 

C7H1402 

(Enanthic     or 

222° 

-10°'o 

Normal  acid  by  oxidation 

Heptoic, 

of  cenanthol  from  castor 

oil  ;   wine  fusel  oil. 

CgHiflOg 

Caprylic    or 

238° 

15° 

Isoprimary     acid     from 

Octoic, 

cokernut  oil  and  butter; 

Limburg  cheese. 

C9HJ802 

Pelargonic       or 

254°                13°         Normal  acid  from  oil  of 

Ennoic, 

Pelargonium    roseum; 

and  oxidation  of  oil  of 

rue  and  beetroot  fusel  oil. 

Ci0Hvo02 

Capric  orDecoic, 

269°                30° 

Butter  ;      cokernut    oil  ; 

grape  fusel  oil. 

CHH2202 

Hendecoic       or 
Undecylic, 

228°  at  1  GO;      28°  "5 
millims.    | 

Hydrogenatiou  of  Hende- 
cenoic  acid  from  distil- 

pressure. 

lation  of  castor  oil. 

... 

35° 

Cocinic  acid  (?)  in  coker- 

nut oil. 

j 

... 

Near  23° 

Umbellulic  acid  (?)  from 

chaulmoogra  oil. 

^12^2402    !  Laurie  or  Dode- 

225°  at  100 

44° 

Laurel     butter    (Laurux 

coic, 

millims. 

nobilis)  ;  Pichurim  bean 

pressure. 

fat  ;       cokernut     oil  ; 

palm  kernel  oil. 

Ci3H26O2 

Tridecoic, 

... 

... 

Supposed  to  be  contained  , 

in  cokernut  oil  ;  doubt- 

ful. 

C14H2802 

Myristic, 

250°  at  100 

54° 

Nutmeg  butter  ;    coker- 

millims. 

nut  oil  ;  dika  fat  ;  cro- 

pressure. 

ton  oil;  spermaceti. 

C15H3002 

Pentadecoic, 

55° 

(?)  Oil  of  Jatropha  curcas. 

FATTY    ACIDS. 


21 


Formula. 

Name  of  Acid. 

Boiling 
Point. 

Melting 
Point. 

Sources. 

C,6H3002 

Pentadecoic, 

53°  -5 

Cetic  acid(?)  from  sper- 

^ 

maceti. 

53° 

Benomargaric      acid    (?) 

from  oil  of  Ben.     Stilli- 

stearic    acid  (?)    from 

|     C16H3202      Palmitic, 

271°'o 

62° 

Stillingia  sebifera. 
Palm    oil.     One    of    the 

at  100 

constituents    of    most 

millims. 

animal  fats.     Sperma- 

pressure. 

ceti  ;  beeswax  ;   Japan 

wax. 

C,7H3402 

Marcraric, 

... 

60° 

From  cetyl  cyanide  ;  for- 

merly supposed  to  be 

contained    in     certain 

fats. 

Daturic, 

... 

55° 

From      oil      of    Datura 

Strammonium. 

C18H36Oo 

Stearic, 

291°  at  100 

69°  "2 

Tallow,   lard,   and  most 

millims. 

animal  solid  fats  ;  Shea 

C,oH3802 

Enneadecoic, 

pressure. 

66° 

butter;  Illipe"  fat. 
From  stearyl  cyanide  (?) 

obtained     along     with 

artificial  margaric  acid. 

C2oH4002 

Arachic  (or  Ara- 

... 

75° 

Earthnut    oil     (Arachis 

chidic);  Butic, 

hypogcea)  ;     butter   (?) 

1 

(Heintz). 

C21H4o02   ! 

72°  -5 

Medullic     acid  (?)    from 

beef  marrow. 

C22H4402 

Benic  or   Beni- 

76° 

Oil  of  Ben  ;  black  mustard 

stearic, 

seed  oil  ;  rape  oil. 

C^H^Og 

Lignoceric, 

8l°" 

Earthnut     oil  ;       beech- 

wood  tar. 

Carnatibic, 

72°  -5 

Carnauba  wax. 

... 

46° 

Paraffinic  acid   (?)   from 

paraffin  wax  and  nitric 

acid. 

C25H5002 

Hyaenic, 

78° 

Hyaena  fat. 

Co6H5202 

Geoceric  acid  (?)  from  dis- 

• 

tillation  of  brown  coal. 

C27H54Oo 

Cerotic, 

78° 

Beeswax;  Carnauba  wax; 

C28B^02 

Chinese  wax. 

cEnEoi 

0 

Melissic, 

... 

88;" 

Oxidation    of    myricylic 

alcohol  from  beeswax. 

«<5, 

Theobromic, 

72"" 

Cacao  butter. 

The  formulae  ascribed  to  several  of  the  acids  named  in  the  pre- 
ceding table  can  hardly  be  regarded  as  established  with  perfect 


22  OILS,    FATS,    WAXES,    ETC. 

certainty  ;  thus  the  cocinic  acid,  CUH22O2,  formerly  supposed  to 
be  contained  in  cokernut  oil,  appears  from  later  researches  to 
be  in  all  probability  only  a  mixture  of  other  acids  of  the  series ; 
and  the  same  remark  applies  to  the  tridecoic  acid,  C13H20O.2, 
from  the  same  source,  which  appears  to  be  simply  a  mixture 
of  lauric  and  myristic  acids.  SimilaYly,  cetic  acid,  C]5H30O2, 
and  the  isomeric  (?)  benomaryaric  and  stillistearic  acids  are  very 
doubtful  bodies ;  the  last  has  been  stated  by  later  observers  to 
be  simply  palmitic  acid,  and  benomargaric  acid  to  be  a  mixture 
of  palmitic  and  myristic  acids.  The  margaric-  acid,  CirH34O2, 
formerly  regarded  as  present  in  animal  fats,  has  been  since 
shown  to  consist  of  a  mixture  of  stearic  and  palmitic  acids 
and  more  or  less  oleic  acid."55"  Again,  the  compositions  ascribed 
to  medullic  acid,  C01H4.7O9 ;  hycenic  acid,  C05H50O0 ;  geoceric 
acid,  C26H52O2;  and  tkeobromic  acid,  C64H128O0,f  require  con- 
firmation as  regards  the  individual  character  and  purity  of 
these  substances.  Of  those  acids  where  the  carbon  present 
lies  between  C1(>  and  C2w,  it  is  noticeable  that  those  of  most 
frequent  and  widely-spread  occurrence,  and  of  which  the  com- 
positions are  ascertained  with  certainty,  always  contain  an 
even  number  of  carbon  atoms;  so  that  it  has  been  supposed 
by  some  chemists  that  acids  containing  an  odd  number  of 
carbon  atoms  do  not  actually  occur  as  glycerides  amongst  the 
natural  oils  and  fats,  and  that  the  bodies  supposed  to  possess 
vsuch  a  composition  are  really  either  mixtures  of  glycerides  with 
even  numbers  of  carbon  atoms,  or  substances  rendered  otherwise 
impure.  A  priori,  however,  there  seems  no  reason  for  doubting 
the  possibility  of  the  existence  in  nature  of  glycerides  of  acids 
containing  an  odd  number  of  carbon  atoms. 

In  the  case  of  butter  fat,  cokernut  oil,  and  some  few  other 
substances,  fatty  acids  of  low  molecular  weight  (i.e.,  where  n  in 
the  general  formula  CnHnnO2  is  of  low  value),  are  present  to 
some  notable  extent ;  but,  as  a  general  rule,  natural  oils  and  fats 
rarely  yield  fatty  acids  of  this  description  where  n  has  a  smaller 
value  than  12.  Inasmuch  as  the  lower  members  of  the  acetic 
acid  family  are  comparatively  easily  volatile  (especially  along 
with  water  vapour),  whilst  the  higher  ones  are  almost  non- 
volatile with  ordinary  steam,  this  practically  means  that  the 
fatty  acids  from  most  fats  and  oils  will  not  readily  distil  by  the 
aid  of  moist  steam,  whilst  a  certain  proportion  of  more  easily 
volatile  acids,  is<  contained  in  the  mixture  of  acids  obtained  from 
butter  fat  and  cokernut  oil,  tfec.  This  distinction  is  utilised  in 
certain  case&  as.  a.  means  of  testing  the  quality  of  such  substances 

*  The  margarine  or  oleomargarine  used  as  a  butter  substitute  is  es- 
ssntially  a  mixture  of  the  glycerides  of  stearic  and  palmitic  acids  with 
sufficient  olein  to  give  it  its  soft  texture. 

t  Graf  was  unable  to  find  any  theobromic  acid  in  Cacao  butter  (Arch. 
Pharm.,  1888,  26,  p.  820). 


FATTY    ACIDS.  23 

as  regards  adulteration  and  admixture  with  cheaper  forms  of 
fatty  matter  (Reichert's  test,  vide  Chap,  vin.) 

The  fatty  acids  of  the  acetic  series  diifer  considerably  in  their 
respective  degrees  of  solubility  in  water ;  the  lowest  members — 
formic,  acetic,  propionic,  and  butyric  acids — are  miscible  with 
water  in  all  proportions^  the  highest  members,  including  myristic 
acid  and  all  above  it,  are  quite  insoluble  in  water ;  the  inter- 
mediate acids  exhibit  a  degree  of  solubility  the  greater  the 
lower  the  molecular  weight ;  thus  caprylic  acid  dissolves  in  400 
parts  of  boiling  water,  and  capric  acid  in  about  1000  parts,  both 
mostly  separating  out  again  on  cooling;  whilst  lauric  acid  is 
almost  insoluble  in  cold  water,  though  sparingly  dissolved  by 
boiling  water. 

Alcohol,  especially  when  warm,  readily  dissolves  even  the 
highest  members  of  the  series ;  inasmuch  as  the  glycerides  of 
these  acids  are,  as  a  rule,  almost  insoluble  in  alcohol,  this  pro- 
perty affords  a  method  of  separating  the  free  fatty  acids  con- 
tained in  natural  oils,  &c.,  from  the  glycerides,  the  oil  being 
simply  agitated  with  alcohol  and  allowed  to  stand  so  as  to 
separate  the  alcoholic  solution  of  fatty  acids  from  the  unaffected 
glycerides.  Alcohol  containing  only  a  minute  quantity  of  a  free 
fatty  acid  exhibits  an  acid  reaction  to  phenolphthalein,  and  can 
accordingly  be  readily  titrated  volumetrically  by  means  of  a 
weak  standard  alkaline  solution  in  presence  of  that  indicator : 
on  this  also  is  based  the  general  method  of  determining  the 
amount  of  fatty  acid  salt  formed  on  saponifying  a  glyceride  or 
other  compound  ether  by  an  alkali  (Chap,  vin.)  The  highest 
acids  of  the  series  are  not  extremely  soluble  in  cold  alcohol,  so 
that  they  are  readily  crystallisable  from  that  menstrum. 

The  normal  salts  of  acids  of  the  acetic  family  are  indicated  by 
the  general  formula  CnH2n+1 .  CO .  OM,  where  M  is  a  monad 
metal :  acids  salts  of  formula  CttHgB.1O2l^  CnH0llO2  can  in  some 
cases  be  produced — e.g.,  sodium  diacetate,  C2H3NaO2,  C2H4O2 ; 
potassium  distearate,  C1SH35K00,  C18H3602.  Salts  of  this  kind 
when  dissolved  in  hot  alcohol  react  acid  with  phenolphthalein, 
and  behave  toward  alkaline  solutions  on  titration  with  that 
indicator  precisely  as  mixtures  of  the  free  acid  and  the  neutral 
salt, 

In  certain  cases  the  neutral  alkali  salts  are  partly  hydrolysed 
by  solution  in  water  with  formation  of  acid  salt  and  caustic 
alkali ;  thus  with  neutral  sodium  stearate. 

Neutral  Sodium  Caustic 

Stearate.  Water.  Soda.  Sodium  Distearate. 

2C18H35Na02    +    H20    =   NaOH    +    C18H35Na02,  Ci8HS602 

By  adding  common  salt  to  the  fluid,  the  latter  compound  and 
the  unaltered  neutral  salt  are  thrown  out  of  solution ;  on  collec- 


24  OILS,    FATS,    WAXES,    ETC. 

tion  by  filtration  and  solution  in  alcohol  and  titration  an  amount 
of  acidity  is  registered  precisely  equivalent  to  the  alkalinity 
of  the  watery  fluid.  On  the  occurrence  of  this  phenomenon 
depends  a  good  deal  of  the  cleansing  properties  of  soaps,  the 
action  being  also  observable  with  the  alkali  salts  of  oleic  and 
ricinoleic  acids  to  approximately  the  same  extent  as  with  those 
of  palmitic  and  stearic  acids  (Chap,  xxn.)" 


ACRYLIC  (OLEIC)  FAMILY  OF  FATTY  ACIDS. 

The  total  number  of  acids  of  general  formula  CnH2n_i.CO  .  OH 
now  known  is  somewhat  considerable ;  as  with  the  acetic 
family,  only  a  comparatively  small  number  of  them  are  con- 
tained in  natural  fats,  &c.,  and  of  these  but  few  are  of  relatively 
low  molecular  weight  so  as  to  be  readily  volatile.  The  table  011 
page  25  exhibits  the  more  important  acids  of  this  class. 

As  in  the  case  of  the  acetic  family  of  acids,  the  existence  of 
certain  members  mentioned  in  the  table  is  not  yet  established 
with  perfect  certainty ;  thus  damaluric  acid  is  a  substance  the 
existence  of  which  requires  confirmation  ;  and  similarly  with 
the  aldepalmitic  acid  recently  stated  by  Wanklyn  to  be  a 
constituent  of  cow's  butter.*  The  existence  of  hypogseic 
acid  has  been  denied  by  Schon,  who  found  the  only  acid  of 
the  acrylic  series  present  in  earthnut  oil  to  be  oleic  acid. 
Similarly,  moringic  acid  has  been  stated  by  more  recent  ex- 
perimenters to  be  simply  impure  oleic  acid;  and  the  same  kind 
of  thing  is  said  by  Schadler  to  apply  to  doeglic  acid  this  being 
regarded  by  him  as  simply  impure  physetoleic  acid. 

The  unsaturated  nature  of  the  hydrocarbons  from  which  this 
group  of  fatty  acids  are  derived  leads  to  their  possession  of  some 
peculiar  features  ;  thus,  when  heated  with  fused  alkali  (caustic 
potash),  there  is  a  tendency  to  undergo  a  change  indicated  by 
the  general  equation  : — 

Cm  +  nH2(m  +  n  _j,02  +  2KOH  =  K.  CmH^-iOg  +  K.CuH2n..102  +  H2 

the  potassium  salts  of  two  acids  of  the  acetic  family  being  formed 
along  with  free  hydrogen.  In  virtue  of  this  tendency,  oleic  acid, 
when  thus  treated,  forms  palmitic  and  acetic  acids,  a  circumstance 
utilised  in  practical  manufacture. 

Oleic  Acid.        Caustic  Potash.      Potassium  Palmitate.        Potassium  Acetate. 

Ci8H3402     +     2KOH     =     K.C,CH3102     +     K.C2H302     +     H2 

Again,  inasmuch  as  the  unsaturated  hydrocarbons  have  a  more 
or  less  marked  tendency  to  combine  directly  with  halogens  (and 

*  Journ.  Soc.  Chem.  Ind.,  Feb.  1891,  p.  89. 


FATTY   ACIDS. 


25 


so  pass  into  the  series  of  substitution  derivatives  of  the  satu- 
rated hydrocarbons),  the  same  tendency  is  shared  by  the  fatty 


Formula. 

Name  of  Acid. 

Boiling  Point 

Melting 
Point. 

Sources. 

C3H402 

Acrylic, 

140°C. 

8°C. 

Oxidation  of  acrole'in  from 

glycerol. 

C4H602 

Crotonic, 

185° 

72° 

From  cyanide  of  allyl  (de- 

rived from  oil  of  mustard). 

C5H802 

Angelic, 

185° 

45° 

Angelica  root.  Sumbul  root 

resin. 

Tiglic, 

196° 

64° 

Oil  of  Chamoinile.     Croton 

oil. 

C6H1002 

Pyroterebic, 

210° 

... 

Action  of  heat  on  terebic  acid 

from  oil  of  turpentine  and 

nitric  acid. 

C7H1202 

... 

... 

53° 

Damaluric  acid?  (from  cow's 

and  horse's  urine). 

CgHi4Oo 

Octenoic, 

... 

... 

... 

c9H16o; 

Ennenoic, 

... 

liquid. 

(Enanthol  (from  castor  oil) 

and  acetic  anhydride. 

Ci0H1802 

Phoronic, 
Decenoic, 

242°-269° 

169° 
10°-86° 

Oxidation  of  sodium  camphor. 
Several  isomeric  modifica- 

tions known  ;  all  of  arti- 

ficial origin. 

CnH2002 

Hendecenoic, 

275° 

24°  -5 

Castor  oil  distilled   under 

diminished  pressure. 

C12H2202 

Petroleumic, 
Dodecenoic, 

250°-  260° 

liquid. 

Contained  in  petroleum. 
Artificial. 

Ci3H2402 

Tridecenoic, 

... 

... 

... 

Ci4H2602 

Tetradecenoic, 

... 

Moringic, 

0° 

Oil  of  Ben. 

Cimicic, 

... 

44° 

Fcetid  oil  from  Raphirjaster 

punctipennis. 

CicH3o02 

Physetoleic, 

30° 

Sperm  oil. 

Hypogaeic, 

... 

34° 

Earthnut  oil(Arachis  Itypo- 

gcea). 

50° 

Aldepalmitic   acid(?)   from 

butter. 

C17H3202 

Heptadecenoic, 

..  . 

... 

Ci8H3402 

Oleic, 

286°  at  100 
millims. 

14° 

Contained  as   glyceride   in 
most     animal    fats     and 

pressure. 

many  vegetable  oils. 

Isoleic, 

44°-45° 

Distillation    of    oxystearic 

acid. 

Stearidic, 

... 

35° 

Action  of  water   on  silver 

bromostearate. 

Cj9H3G02 

Doeglic, 

A  little 

Oil    from   dcegling   (bottle- 

above  0° 

nose  whale). 

C21H4002 

;.'! 

'... 

'.'.'.                 ... 

C22H4202 

Erucic, 

254°  -5  at 

34° 

Colza,     grape    seed,     and 

10  millims. 

mustard  oils. 

pressure. 

26  OILS,    FATS,    WAXES,    ETC. 

acids  derived  from  them ;  thus  the  hydrocarbon  ethylene,  as  has 
long  been  known,  combines  directly  with  chlorine  forming  an 
oily  fluid,*  originally  known  as  "Dutch  liquid,"  the  reaction 
being 

Ethylene.  Chlorine.         Ethylene  Bichloride. 

H2C  =  CH2     +     C12     =     H2C1C  -  CC1H2 

In  the  same  kind  of  way,  oleic  acid  and  its  congeners,  being 
derivatives  of  ethylene  of  general  formula  K .  CH  =  CH .  S, 
will  directly  combine  with  bromine  or  iodine  in  parallel  fashion, 
forming  dibromo-,  or  diiodosubstitution  derivatives  of  acids  of 
the  acetic  family  of  form  R .  CHBr  -  CHBr .  S  ;  thus— 

Oleic  Acid.  Iodine.  Diiodostearic  Acid. 

C18H3402        +        I2        =        CjgHsJjOjj 

This  reaction  is  utilised  as  a  convenient  method  of  dis- 
tinguishing from  one  another  acids  derived  respectively  from 
saturated  hydrocarbons,  and  from  unsaturated  hydrocar- 
bons of  the  olefine  series,  the  former  not  combining  with 
halogens,  and  the  latter  uniting  therewith  in  the  proportion  of 
one  molecule  of  fatty  acid  to  two  atoms  of  halogen.  Accord- 
ingly, the  measurement  of  the  quantity  of  iodine  or  bromine 
thus  fixed  ("iodine  absorption  equivalent,"  or  "bromine  ab- 
sorption equivalent")  often  gives  useful  information  as  to  the 
nature  of  the  fatty  acid  or  acids  present ;  and  the  same  remark 
equally  applies  to  the  glycerides  themselves,  which  also  combine 
with  halogens  in  parallel  fashion,  e.g.  : — 

Olein.  Glyceride  of  Glyceride  of  Diiodo- 

Oleic  Acid.  Iodine.  stearic  Acid. 

CgJU^CisH-ssO^s     +        3I2       =      ^3^-5(^13^53^2^2)3 

In  just  the  same  kind  of  way  certain  acids  of  the  acrylic  family 
can  directly  combine  with  nascent  hydrogen  produced  under 
appropriate  conditions,  becoming  thereby  converted  into  acids  of 
the  acetic  family,  the  general  reaction  expressing  the  change 
being — 

CnH2n.202     +     Ho     =     CnH2n02 

Thus  oleic  acid  forms  stearic  acid,  when  heated  in  a  sealed 
tube  with  fuming  hydriodic  acid  and  phosphorus.  By  reversing 
the  process,  an  acetic  acid  becomes  transformed  into  an  acrylic 
acid.  In  practice  the  direct  removal  of  hydrogen  after  this 
fashion  is  difficult  to  accomplish  ;  but  in  certain  cases  it  may  be 
effected  by  acting  on  the  acid  of  the  acetic  family  with  chlorine 
or  iodine  or  bromine,  so  as  to  produce  a  monochloro-,  iodo-,  or 
bromosubstitution  derivative;  by  treating  this  with  alkalies,  &c., 

*  Whence  the  old  name  olefiant  gas  for  ethylene,  signifying  "  oil  making" 
gaa. 


FATTY.    ACIDS.  27 

the  elements  of  HC1,  HI,  or  HBr  are  eliminated,  leaving  an  acid 
of  the  acrylic  series. 

Thus  acrylic  acid  itself  is  formed  from  iodopropionic  acid  thus, 

lodopropionic  Acid.  Acrylic  Acid. 

C3H5I02     -     HI     =     C3H402 

the  elimination  of  the  elements  of  hydriodic  acid  being  brought 
about  by  treatment  with  sodium  ethylate,  lead  oxide,  or  similar 
basic  substances. 

In  other  cases  a  dibromo-  or  dichlorosubstitution  derivative  of 
an  acid  of  the  acetic  family  is  acted  upon  with  zinc  dust,  or  other 
substance  having  a  strong  tendency  to  combine  with  halogens  ; 
thus  dibromopropionic  acid  and  zinc  dust  form  acrylic  acid. 

Dibromopropionic  Acid.  Acrylic  Acid. 

C-jH^BraOo     —     Br2     =     G'sH^Og 

In  this  way  the  dibrominated  and  diiodised  products  obtained 
by  adding  Br.2  or  I2  to  the  higher  acrylic  acids  can  be  made  to 
reproduce  the  original  acid.  This  reaction  is  utilised  in  the 
examination  of  oils,  &c.,  containing  the  glycerides  of  unsaturated 
acids  ;  bromine  addition  products  are  formed  and  separated  from 
one  another  by  crystallisation,  &c.,  and  then  debrominated  so  as 
to  reproduce  the  original  acids,  which  can  thus  be  indirectly 
separated  from  one  another  in  a  fashion  usually  impracticable 
with  the  actual  acids  themselves. 

Acrylic  acids,  at  any  rate  in  certain  cases,  combine  directly 
with  sulphuric  acid,  forming  saturated  compound  sulphuric  acids 
analogous  to  ethylsulphuric  acid  (sulphovinic  acid)  ;  thus  — 

Oleic  Acid.  Sulphuric  Acid.  Oxystearosulphuric  Acid. 

C17H33.CO.OH     +     S02(OH)2     =     CirH 


By  the  action  of  water,  &c.,  on  the  compounds  thus  formed, 
hydrolysis  is  brought  about,  with  the  formation  of  sulphuric  acid 
and  an  acid  of  the  oxyacetic  (glycollic)  family  ;  thus  — 

Oxystearosulphuric  Acid.  Water.  Sulphuric  Acid.  Oxystearic  Acid. 

Ci;H34-  -f     H20     =     S02(OH)2     +     Ci7H34 


These  reactions,  especially  the  first,  are  utilised  in  the  pro- 
duction of  certain  kinds  of  "Turkey  red  oils;"  obviously  the 
sum  of  the  two  changes  is  equivalent  to  the  addition  to  an 
acrylic  acid  of  the  elements  of  water. 

The  dibromides  of  acids  of  the  oleic  series,  when  treated 
with  silver  hydroxide,  Ac.,  form  silver  bromide  together  with 
glyceric  acids  —  i.e.,  dioxy  acids  of  the  acetic  series  :  — 

+    2AgOH    =   2AgBr    +  CnH.n_ 


28  OILS,    FATS,    WAXES,    ETC. 

By  the  regulated  action  of  caustic  potash,  they  lose  successively 
HBr  and  2HBr,  forming  in  the  one  case  bromoleic  acid  or  a 
homologue  thereof,  and  in  the  other  case  a  propiolic  aqid— 

CO.  OH  HBr    =  C"  Hsn-3 1  CO.  OH 

£j*  QH      -   t>HBr   =  Cn  H,n_., .  CO.  OH 

A  remarkable  property  possessed  by  many  acids  of  the  oleic 
family  is  that  contact  with  certain  reagents,  more  especially 
nitrous  acid,  converts  them  into  isomeric  modifications  of  higher 
fusing  and  boiling  points,  so  that  acids  liquid  at  the  ordinary 
temperature  become  transferred  into  solids.  This  effect  is  also 
produced  with  the  natural  glycerides  of  these  acids,  forming 
a  reaction  largely  utilised  in  testing  the  purity  of  certain  oils 
(Chap.  vii).  Oleic  acid,  liquid  at  ordinary  temperatures,  thus 
becomes  elaidic  acid,  melting  at  45°,  by  contact  with  nitrous 
acid ;  and  its  glyceride,  olein,  fluid  at  0°,  is  similarly  converted 
into  elaidin,  melting  at  32°;  whence  the  term  "Elaidin  reaction" 
applied  to  this  nitrous  acid  test.  In  similar  fashion  erucic 
acid,  melting  at  34°,  is  changed  into  brassaidic  or  brassic*  acid, 
fusing  at  60° ;  whilst  parallel  changes  are  undergone  by  hypo- 
gseic  and  physetoleic  acids. 

Elaidic  acid  and  the  similarly  altered  other  acids  of  this  class 
call  be  distilled  unchanged  under  diminished  pressure,  not  being 
thereby  converted  back  again  into  the  original  acids  ;  for  a  given 
pressure  the  boiling  point  is  always  slightly  higher  than  that  of 
the  original  acid  :  thus  Krafft  and  Noerdlinger  f  obtained  the 
following  numbers.  (See  Table,  p.  29.) 

The  nature  of  the  chemical  change  ensuing  during  the  elaidin 
reaction  is  somewhat  uncertain.  By  fusion  with  caustic  potash 
both  oleic  and  elaidic  acids  yield  acetate  and  palmitate  ;  on  the 
other  hand,  by  oxidation  with  alkaline  permanganate  they  form 
two  different  dioxystearic  acids,  melting  respectively  at  136° '5 
(solidifying  at  119°)  and  99°-100°  (solidifying  at  S5°-86°— Saytzeff). 
Similarly  erucic  and  brassic  (brassaidic)  acids  give  rise  to  two 
different  dioxybenic  acids  on  oxidation,  as  well  as  different 
derivatives  of  other  kinds. 

*  The  term  "  brassic  acid  "  (brasxica  .mure)  was  originally  applied  to  the 
acid,  C22H42O2,  obtained  from  various  species  of  Brassica,  there  being  at 
that  time  some  doubt  whether  "erucic  acid"  obtained  from  other  ana- 
logous sources  was  or  was  not  identical  therewith.  Later  on  the  identity 
was  established,  and  the  term  "  brassaidic  acid  "  (brassidin  siiure)  was 
applied  to  the  product  of  nitrous  acid  on  erucic  acid,  to  indicate  its  analogy 
with  elaidic  acid  (Haussknecht,  Annalen  der  Chem.  and  Pharm.,  1867, 
143,  p.  55).  Of  late  years  the  term  "  brassic  acid  "  has  been  mostly  substi- 
tuted in  English  chemical  literature  for  "brassaidic  acid  (c. .7.,  Morley  and 
Muir's  Dictionary  of  Chemistry,  vol.  i.,  p.  631,  article  Brassic  Acid}. 

t  Berichte  der  Dent.  Chem.  Cn<s.,  1889,  vol.  xxii.,  p.  819. 


FATTY    ACIDS. 


29 


Millimetres  of 
Mercury. 

Oleic  Acid. 

Elaidic  Acid. 

100 
50 
30 
15 
10 

285-5—286 
264 
249-5 
232-5 
223 

287'5—288 
266 
251-5 
234 
225 

Erucic  Acid. 

Brassic  Acid. 

30 
15 
10 

281 
264 
254-5 

282 
265 
256 

From  Erucic  Acid. 

Melts  at 

Dioxybenic  acid,  .  .  132°- 133° 
Dibromide  of  erucic  acid,  42°-43° 
Bichloride,  .  .  .  46° 

Methylester  from  dichloride,   30 '5° 


From  Brassic  Acid. 

Melts  at 

Isodioxybenic  acid,  .     9S°-99° 

Dibromide  of  brassic  acid,  54° 

Dichloride,        .         .         .  65° 

Methylester  from  dichloride,    42° -5 


According  to  recent  researches  *  the  isomerism  of  erucic  and 
brassic  acids  is  of  the  stereochemical  order — i.e.,  the  "structures" 
of  the  two  bodies,  when  expressed  in  space  of  three  dimensions, 
are  not  superposible ;  a  difference  only  imperfectly  expressible 
on  a  flat  surface  by  the  formulae — 

CigHsj)     —     C     —     H  CjgHjjg     —     C     —     H 

II  and  || 

H   -  C   -  C02H  C02H  -  C   -  H 

Isomerides  of  Oleic  Acid. — Besides  elaidic  acid  (formed 
from  oleic  acid  by  contact  with  nitrous  acid),  two  other  acids 
isomeric  with  oleic  acid  are  known,  viz.,  isoleic  and  stearidic 
acids ;  in  addition,  other  isomerides  of  the  anhydride  character 
exist. 

Isoleic  acid  is  obtained  by  acting  on  oleic  acid  with  sulphuric 
acid ;  combination  takes  place  with  the  formation  of  oxystearo- 
sulphuric  acid  (probably  two  different  modifications),  thus — 

C17H33.CO.OH  +  H2S04  =  C17H34 

By  hydrolysis  the  product  forms  oxystearic  acid  (again,  probably 
more  than  one  modification),  which  on  distillation  under  dimin- 
ished pressure  becomes  dehydrated,  furnishing  a  mixture  of  ordi- 
nary oleic  acid  and  a  solid  isomeride,  isoleic  acid. 

f*       TT          JO.     oU3U  .  TT     f\  TT    O/-V  .  /~<        TT  I    OJ~I 


OH 


H20     =     H2S04     +    C,7 
-     H20     +     CI7H33  .  CO  .  OH 


A.  Holt,  Berichte  der  Deutsch.  Chem.  Ges.,  1891,  vol.  xxiv.,  4120. 


30  OILS,    FATS,    WAXES,    ETC. 

By  converting  the  acids  into  zinc  salts  and  heating  with  alcohol 
a  solution  is  obtained  from  which  zinc  isoleate  separates  on  cool- 
ing, the  other  zinc  salt  remaining  in  solution.  The  acid  obtained 
from  the  pure  zinc  salt  by  decomposition  by  a  mineral  acid, 
crystallises  from  ether;  it  melts  at  45°,  but  is  not  identical  with 
elaidic  acid  which  fuses  at  nearly  the  same  temperature  :  like 
oleic  and  elaidic  acids  it  forms  acetate  and  palmitate  on  fusion 
with  caustic  potash ;  but  the  dibromide  formed  by  combination 
with  bromine  when  treated  with  silver  hydroxide  forms  a  dioxy- 
stearicacid  melting  at  77°-78°  and  solidifying  at  65°-66°,  the  same 
substance  being  also  formed  by  oxidising  isoleic  acid  with  alka- 
line permanganate ;  whereas  the  dioxystearic  acids  obtained  by 
oxidising  oleic  and  elaidic  acids  in  the  same  way  melt  at  136° '5 
and  99°-100°,  and  solidify  at  119°  and  85°-86°  respectively.* 

Isoleic  acid  combines  with  hydriodic  acid,  forming  an  iodo- 
stearic  acid  reducible  to  ordinary  stearic  acid  by  means  of  nascent 
hydrogen,  and  reconverted  into  isoleic  acid  by  alcoholic  potash. 
The  dibromide  of  isoleic  acid  similarly  reproduces  isoleic  acid  on 
treatment  with  zinc  and  hydrochloric  acid. 

Stearidic  Acid. — By  the  action  of  water  on  bromostearic  acid 
(from  bromination  of  stearic  acid)  Oudemannsf  obtained  an  acid 
isomeric  with  oleic  acid,  together  with  silver  bromide.  This 
product  distilled  unchanged  :  melting  point  35°. 

Two  anhydrides  of  oxystearic  acids  are  also  known,  isomeric 
with  oleic  acid;  viz.,  stearolactone,  ^-oxystearic  "inner"  anhy- 
dride (p.  39) ;  and  the  body  formed  by  the  action  of  hydrochloric 
acid  on  a-oxystearic  acid,  regarded  as — 

CO. 
O.  C 


PROPIOLTC  (LINOLIC)  FAMILY  OF  FATTY  ACIDS. 

But  few  members  of  the  family  of  acids  of  general  formula 
CUH2I,  _  3 .  CO .  OH  have  been  as  yet  isolated  from  oils  and  fats, 
&c.,  the  best  known  example  being  linolic  acid,  Cl7H3j .  CO .  OH^ 
contained  in  various  drying  oils,  notably  linseed  oil ;  several 
other  members,  however,  have  been  produced  from  acids  of  the 
oleic  series  by  employing  the  method  founded  on  the  same 
principle  as  that  by  means  of  which  oleic  acids  are  obtainable 
from  acids  of  the  acetic  acid  series — viz.,  by  conversion  into  a 
chloro-  or  bromoderivative  of  an  acetic  acid  and  removal  of  the 
elements  of  HC1  or  HBr  by  the  action  of  a  base.  Thus  oleic 
acid  combined  with  Br2  and  the  product  treated  with  alcoholic 
potash  furnishes  stearolic  acid — 

*  M.  C.  and  A.  Saytzeff,  /.  prakt.  Chem.,  1888,   37,  p.  269. 
t«/.  prakt.  Chemie,  89,  p.  193. 


FATTY    ACIDS.  31 

Oleic  Acid.  Dibromostearic  Acid. 

C]8H3402   +  Br2  C18H34Br202 

Dibromostearic  Acid.  Steai-olic  Acid. 

C18H34Br202     —      2HBr     =     C18H3202 

In  similar  fashion  other  homologues  of  stearolic  acid  (e.g.,  Jiende- 
colic,  palmitolic,  and  benolic  acids)  are  obtainable  from  the  corre- 
sponding homologues  of  oleic  acid,  the  general  reaction  being  — 

CnH2ll_2Br202     -     2HBr     =     CuH2n_402 

In  certain  cases  propiolic  acids  may  be  directly  obtained  from 
acids  of  the  acetic  family  by  treatment  with  chlorine  or  bromine, 
so  as  to  produce  dichloro-  or  dibromoderivatives  of  formula 
CnH2,,  _  0Br2O2,  which  are  then  acted  upon  with  alkalies  so  as  to- 
remove  the  elements  of  2HBr,  in  accordance  with  the  above 
equation  ;  the  total  change  produced  being  therefore  equivalent 
to  the  removal  of  H4.  In  this  way,  for  instance,  myristic  acid, 
C14H2SO2,  forms  myristolic  acid,  C14H2402. 

An  analogous  result  is  brought  about  with  rnonochloro-  or 
monobromoderivatives  of  acids  of  the  acrylic  series  by  similar 
treatment,  the  elements  of  HC1  or  HBr  being  removed,  thus  — 


-       HC1       =      CuH2n.402 
CuHon_3Br02       -       HBr       =       CuH2n-4O2 

For  instance,  chlorocrotonic  acid,  C4H5C102,   gives  rise   by  this 
treatment  to  tetrolic  acid,  C4H4O2. 

The  table  on  p.  32  includes  the  chief  acids  of  this  series:  — 
Just  as  one  molecule  of  an  acrylic  acid  will  combine  with  I2  or 
Br0,  so  will  one  of  a  propiolic  acid  unite  with  Br4  or  I4,  this  action 
being  substantially  the  reverse  of  that  above  described,  where  a 
dibromoacetic  acid  loses  2  HBr  and  becomes  a  propiolic  acid;  this; 
reaction  is  utilised  in  the  practical  testing  of  oils  (Chap,  viu.) 
Conversely,  by  the  action  of  nascent  hydrogen,  zinc  dust,  and 
similar  dechlorinising  agents,  the  tetrabrominated  or  tetra- 
iodised  bodies  thus  formed  become  again  reduced  to  the  original 
propiolic  acids  ;  thus  linolic  acid  can  be  separated  from  accompany- 
ing acids  (obtained  by  saponifying  the  mixture  of  glycerides  con- 
tained in  linseed  oil,  <fec.)  by  combining  with  bromine,  separating 
by  crystallisation  the  tetrabrominated  derivative,  C18H32Br4O2 
(melting  at  114°-115°),  and  reproducing  linolic  acid  by  removing 
the  bromine. 

Tetrabromostearic  Acid.  Linolic  Acid. 

C18H32Br402     -     Br4     =     C18H3202 

Those  propiolic  acids  that  are  formed  by  the  bromine  reaction 
above  described  (loss  of  2HBr  from  dibromoderivatives  of  acids 
of  the  acetic  family)  possess  the  power  of  directly  combining 
with  oxygen  (from  suitable  oxidising  agents),  forming  saturated 


32 


OILS,    FATS,    WAXES,    ETC. 


Formula. 

Name  of  Acid. 

Melting 
Point. 

Boilinc 
Point. 

Sources. 

C3H202 

Propiolic, 

Chloropropiolic     acid, 

C3HC102,   is  formed 

. 

by  the  action  of  pot-  ; 

ash  on  dichloracrylic 

acid,  C3H2CL02. 

C4H202 

Tetrolic, 

76-5° 

203° 

Chlorocrotonic  acid  and 

caustic  potash. 

C5H602 

Pentolic, 

... 

... 

... 

C6H802 

Sorbic, 

Liquid 

221°  ) 

at  15° 

Mountain  ash  berries. 

Parasorbic, 

134-5° 

...    ) 

C7H1002 

Benzoleic(Hy- 

Liquid 

Hydrogenation  of  ben- 

drobenzoic), 

zoic  acid. 

C8H1202 

Diallyl  acetic, 

Liquid 

227° 

Artificial. 

cM, 

Camphic, 

... 

... 

Formed  together  with 
borneol    by    heating 

camphor    with   alco- 

holic soda. 

Campholenic, 

... 

Near 

Dibromcamphor     and 

CnHjsO, 

Hendecolic 

59°  -5 

260° 

sodium  amalgam. 
From     undecylenic 

(Undecolic  or 

(hendecenoic)       acid 

Hendecinoic), 

by  bromine  reaction. 

C12H2002 

... 

... 

... 

... 

CnH^Oo 

Myristolic, 

12°" 

... 

From     myristic     acid 

by  chlorination   and 

action    of    alcoholic 

potash. 

C^HssOj 

Palmitolic, 

42°" 

From    hypogeeic    acid 

by  bromine  reaction. 

C17H3002 

Elceomargaric, 

48° 

...    / 

"  Wood      oil  "      from 

Eloeostearic, 

71° 

...    \ 

Elceococca  Vernitia. 

Cj8H3<>02 

Stearolic, 

48° 

... 

From    oleic     acid    by 

bromine  reaction. 

Linolic, 

Fluid 

... 

Linseed  and  other  dry- 

ing oils. 

Ricilinolic, 

Fluid 

... 

Dehydration  of  ricin- 

oleic  acid. 

Tariric, 

50°  -5 

... 

Seeds  of  tariri  (genus 

Picramnia). 

CgoHgeO* 

...             '... 

Fluid 

(?)  Higher    homologue 

of  linolic   acid,   sup- 

posed    to     be     con- 

tained in  some  drying 

oils. 

c!2H4oOa 

Behenolic  (or 

5T-5 

... 

From   erucic  acid,  by 

Benolic), 

bromine  reaction. 

FATTY    ACIDS.  33 

compounds  by  the  addition  of  two  oxygen  atoms  instead  of  four 
bromine  atoms,  thus— 

Propiolic  Acid.  Saturated  Compounds. 

CnH2n-3'  CO  .  OH      +       Br4     =         Cii  H2n  -3 


(  =0 
CnH2u_3.CO.OH     +     0,     =     CuH2a_3      =0 

(  -CO.  OH 

In  this  way  stearolic  acid,  C18H32O2,  forms  stearoxylic  acid, 
C18H32O4  ;  and  similarly  with  palmitolic  and  benolic  acids. 
The  general  character  of  the  action  is  indicated  by  the  equation  : 


R  .  CH-CH  .  S  .  CH=CH  .  T  +  02=R  .  CH-CH  .  S  .  CH-CH  .  T 

Linolic  Acid.  —  The  earlier  researches  on  the  acids  derivable 
from  the  chief  glycerides  contained  in  linseed  and  other  drying 
oils  led  to  the  conclusion  that  they  were  identical,  and  indicated 
by  the  formula  C10H28O2,  and  to  this  body  the  name  linoleic 
acid  was  applied  ;  but  later  experiments  have  shown  conclusively 
that  a  considerably  higher  molecular  weight  is  possessed  by  the 
acid  obtained  from  linseed  oil,  and  have  rendered  it  not  impro- 
bable that  different  homologous  acids  exist  (related  as  myristic, 
palmitic,  and  stearic  acids,  for  example),  and  that  different 
drying  oils  are  not  always  identical  as  regards  the  leading  acid 
of  this  series  present.  Linolic  acid  was  originally  obtained  by 
Schiller  by  saponifying  linseed  oil  with  caustic  soda,  salting  out, 
dissolving  in  water,  and  precipitating  with  calcium  chloride. 
The  precipitate  was  treated  with  ether,  whereby  calcium  lino- 
late  was  dissolved  out,  leaving  other  substances  undissolved  ; 
by  agitating  the  ethereal  solution  with  hydrochloric  acid,  and 
evaporating  at  a  low  temperature  in  an  atmosphere  of  hydrogen, 
crude  linolic  acid  was  obtained.  This  was  purified  by  treat- 
ment with  alcoholic  ammonia,  precipitating  as  barium  salt, 
and  regenerating  the  acid  as  before.  The  analysis  of  the  acid 
and  its  salts  by  Schiller,  and  subsequent  investigators,  led  to 
the  formula  C1(.(H08O2. 

On  the  other  hand,  the  Koettstorfer  values  (Chap,  viu.)  for  lin- 
seed oil  and  other  drying  oils  obtained  by  most  of  the  later  experi- 
menters lead  to  the  conclusion  that  the  mean  molecular  weight  of 
the  fatty  acids  contained  therein,  is  sensibly  higher  than  252, 
the  value  corresponding  with  C16H28O2  ;  the  saponification 
equivalents  for  linseed,  poppy,  and  hemp  oils  thus  deduced 
mostly  lie  between  285  and  300,  giving  an  average  of  293  or 
thereabouts  for  the  glycerides,  and  consequently  of  about  280 
for  the  fatty  acids  thence  derivable  (C1SH32O2  =  280).  Further, 
various  later  analyses  of  linolates  and  other  derivatives  corro- 

3 


34  OILS,    FATS,    WAXES,    ETC. 

borate  this  formula;  whilst  Peters*  obtained  stearic  acid  (of 
melting  point  69°)  by  acting  on  linolic  acid  with  strong  hydriodic 
acid  and  phosphorus,  so  as  to  hydrogenise  it. 

Still  higher  molecular  weights  result  from  the  observations  of 
some  chemists.  Thus  A.  H.  Allen  f  found  that  whilst  the  linolic 
acids  isolated  from  several  different  samples  of  linseed  oil  pos- 
sessed mean  equivalent  weights  varying  between  282  and  295, 
another  specimen,  prepared  with  great  care  in  an  atmosphere  of 
coal-gas,  gave  307 -2  (C2pH3602  =  308).  Norton  and  Eichardson  % 
found  that  linolic  acid  from  linseed  oil,  when  distilled  at 
about  290°  under  a  pressure  of  89  mm.,  gave  a  colourless 
distillate,  constituting  about  three-quarters  of  the  whole  ;  this 
was  capable  of  being  redistilled  unchanged.  It  consisted  of 

15° 
an   acid   of  specific   gravity   -9108    at  -—    giving   numbers    on 

analysis  corresponding  with  the  formula  C20H36O2 ;  the  vapour 
density  was  found  to  be  153,  this  formula  representing  154. 
Moreover,  on  heating  with  hydriodic  acid  it  did  not  form  stearic 
acid,  melting  at  69°,  as  in  the  case  of  Peter's  product,  but  an 
acid  of  considerably  higher  melting  point — 83°  (arachic  acid, 
C20H40O2,  melts  at  75°). 

Reformatsky§  on  repeating  the  experiments  of  Schuler,  obtained 
from  linseed  oil  freshly  expressed  in  the  laboratory  a  crude 
linolic  acid  that  did  not  distil  unchanged  at  292°  under  100  mm. 
pressure.  It  contained  a  considerable  amount  of  oleic  acid, 
yielding  dioxystearic  acid  on  oxidation  with  permanganate ;  by 
heating  with  alcohol  and  gaseous  hydrochloric  acid,  ethyl  linolate 
was  ultimately  obtained,  distilling  at  270-275  under  180  mm. 
pressure ;  from  this  by  saponification  linolic  acid  was  regener- 
ated in  a  state  of  comparative  purity  ;  e.g.,  giving  the  iodine 
number  172-65  to  180-3,  that  calculated  being  181-4.  When 
dissolved  in  glacial  acetic  acid  the  product  thus  prepared  formed 
two  compounds  on  addition  of  bromine — viz.,  a  tetrabromide 
(addition  product),  C18H3200Br4,  as  a  viscid  oil ;  and  a  crystallis- 
able  hexabrominated  substance,  regarded  by  him  as  a  bromosub- 
stitution  derivative  of  the  tetrabromide,  C18H30O2Br6,  melting  at 
177°-178°  and  solidifying  at  175°.  Oxidation  with  alkaline  per- 
manganate yielded  tetroxystearic  (sativic)  acid  and  a  little  azelaic 
acid. 

Whilst  it  appears  exceedingly  probable  from  the  preceding  re- 
sults that  more  than  one  homologous  acid  of  the  series  CnH2n_  4O^ 
exists  in  ordinary  drying  oils,  it  is  more  than  doubtful  whether 
any  single  substance  in  a  state  of  purity  was  examined  by 

*  Monatsh.  f.  Chemie,  1886,  7,  p.  552. 
t  Commercial  Organic  Analysis,  vol.  ii.,  1886,  p.  117. 
J  Berichte  (L  Deut.  Chem.  Ges.,  1887,  xx.,  p.  2735. 

§Journ.  Soc.  Chem.  Industry,  1890,  p.  744  :  from  /.  prakt.  Chem.,  1890, 
41,  p.  529. 


FATTY   ACIDS.  35 

any  of  the  various  observers,  inasmuch  as  purification  by 
recrystallisatioii  of  a  well  marked  crystalline  derivative  was 
not  found  readily  practicable.  On  the  other  hand,  Hazura  and 
Griissner  obtained  from  hemp  seed  oil*  a  mixture  of  fatty 
acids  which  on  solution  in  acetic  acid  and  treatment  with 
bromine  gave  more  than  one  brominated  product  of  crystal- 
lisable  character,  as  well  as  iioncrystalline  ones.  One  of  the 
crystallisable  products  was  found  to  melt  at  177°-178°,  and 
to  have  the  composition  018H30O2Br6 ;  another  melted  at 
114°-115°,  and  had  the  composition  C18H32O2Br4;  from  this  latter 
by  the  action  of  zinc  and  alcoholic  hydrochloric  acid  the  bromine 
was  removed,  producing  linolic  acid,  C18H.>9O.7,  free  from  ad- 
mixture with  other  acids.  It  was  found  impracticable  to  bromi- 
nate  the  bromine  compound,  C18H3.2O2Br4,  so  as  to  obtain  from  it 
any  substitution  derivative,  C3  8H30O2Br(3 ;  whence  it  appears  that 
the  hexabrominated  body,  melting  at  177°-178°,  was  not  formed 
by  the  further  substitutive  action  of  bromine  on  the  tetrabromi- 
nated  addition  product  (as  supposed  by  Reformatsky),  but  must 
have  been  produced  by  the  direct  combination  of  Br6  with  an 
acid,  C18H<]0O0,  contained  along  with  linolic  acid,  &c.,  in  the 
original  mixture  ;  this  acid,  linolenic  acid,  is  in  fact  easily  repro- 
duced from  the  hexabromicle  by  treatment  with  zinc  and  alco- 
holic hydrochloric  acid  so  as  to  remove  the  bromine  (p.  27)  ; 
conversely,  it  is  again  converted  into  the  original  hexabromide 
by  direct  combination  with  Br6. 

The  linolic  acid  thus  obtained  from  the  tetrabromide  of  fusing 
point  114°-115°,  C18H32O2Br4,  reproduced  that  substance  by 
combination  with  bromine ;  and  similarly  combined  with  I4, 
but  did  not  form  a  hexabrominated  derivative ;  on  oxida- 
tion with  alkaline  permanganate  it  formed  a  tetroxystearic 

acid,  sativic  acid,  018H3G0G    ==    CirH'31    I  £,Q   ^jj  ,  together  with 

a  little  azelaic  acid  and  other  secondary  products,  but  no  linusic 
acid  (p.  37).  Sativic  acid  fuses  at  170°  ;f  on  heating  with 
hydriodic  acid  and  phosphorus,  it  forms  an  iodised  acid,  reduced 
to  stearic  acid  by  means  of  zinc  and  hydrochloric  acid ;  it  dis- 
solves in  1000  parts  of  boiling  water,  and  is  readily  soluble  in 
alcohol,  but  is  insoluble  in  cold  water  and  in  ether;  by  acety- 

lation    it    forms    a  tetracetyl    derivative,    C17H31  <  £,Q   j^j|    '4; 

hence  it  obviously  possesses  the  constitution  of  a  quadruply 
hydroxylated  stearic  acid.  On  further  oxidation  it  does  not  form 
linusic  acid,  but  produces  azelaic  acid,  C*-H14(CO .  OH)2. 

Isomerides  of  Linolic  Acid. — Stea/rolic  acid,  obtained  by 
combination  of  oleic  acid  with  Br2,  and  removing  the  elements  of 

*  Journal  Soc.  Clie.m.  Industry,  1888,  p.  506  :  from  MonatsJi.  d.  Chemie> 
ix..p.  180. 

t  According  to  earlier  observations,  at  160°-162°. 


36  OILS,    FATS,    WAXES,    ETC. 

2HBr  from  the  product,  fuses  at  48°.  By  oxidation  with  alka- 
line permanganate,  this  forms  stearoxylic  acid,  C18H82O4>  melting 
at  84°-86°,  together  with  some  suberic  acid,  C6H"12(CO.OH)2, 
produced  by  the  further  oxidation  of  the  stearoxylic  acid  first 
formed  (Hazura).  Nitric  acid  also  directly  oxidises  it  to  stear- 
oxylic acid,  with  formation  also  of  azelaic  acid,  C7H14(CO.OH)2 
(Overbeck),  and  of  pelargonic  (ennoic)  acid  (Limpach). 

Tariric  Acid. — A.  Arnaud  has  recently  described*  an  acid 
isomeric  with  linolic  acid  contained  as  triglyceride  in  the 
seeds  of  "  tariri,"  a  shrub  common  in  Guatemala ;  it  melts  at 
50° '5  C.,  and  unites  with  bromine,  forming  a  tetrabromide, 
C18H32Br4O2,  melting  at  125°. 

Ricilinolic  Acid. — This  name  may  be  conveniently  applied  to 
the  acid  obtained  by  Krafft,f  by  heating  ricinoleic  acid  under 
diminished  pressure  (15  mm.),  when  an  acid  distilled,  liquid  at 
ordinary  temperature,  but  solidifying  on  chilling ;  this  boiled  at 
230°  at  15  mm. ;  and  gave  numbers  indicating  that  it  was  an 
isomeride  of  linolic  acid,!  produced  by  the  dehydration  of 
ricinoleic  acid,  which  might  be  expected  a  priori  to  take 
place,  thus — 

Ricinoleic  Acid.  Dehydrated  Derivative. 

C1'H^  H2°     +     C17HSi.CO.OH 


LINOLENIC  FAMILY  OF  FATTY  ACIDS. 

The  existence  in  drying  oils  of  two  isomeric  acids  of  formula 
CnH.2n_5.CO.OH  (where  n=  17)  in  the  form  of  glycerides  has  been 
rendered  extremely  probable,  if  not  conclusively  substantiated, 
by  Hazura  and  various  collaborateurs.  When  the  fatty  acids 
isolated  from  such  oils — e.g.,  hempseed  or  linseed  oil — are  dis- 
solved in  acetic  acid,  at  least  three  different  brominated 
compounds  are  obtainable  by  the  addition  of  bromine — viz., 
crystallisable  linolic  acid  tetrabromide,  C18H32O2Br4,  melting 
at  114°-115°,  and  the  crystallisable  hexabromide,  C18H30OoBr6, 
melting  at  177°-178°  above  described  (p.  35),  together  with  a  non- 
crystallisable  liquid  bromide,  apparently  containing  an  isomeric 
hexabromide,  018H80O2Br6.  As  already  stated,  the  crystallisable 
hexabromide  loses  Br6  by  the  action  of  zinc  and  alcoholic  hydro- 
chloric acid,  forming  linolenic  acid,  C18H30O9,  from  which  the 
same  hexabromide  can  be  reproduced  by  bromination ;  by 
oxidation  with  alkaline  permanganate  no  sativic  acid  is  pro- 

*  Comptes  rendus,  114,  p.  79. 

t  Eerichte  d.  Deut.  Chcm.  Ges.,  1888,  p.  2730. 

+  By  heating  ricinoleic  acid  in  vacno,  Norton  and  Richardson  obtained  an 
acid  closely  resembling  linolic  acid,  regarded  by  them  as  C2oH3C02  (Bcrichte 
d.  Deut.  Chem.  Ges.,  1887,  xx.  p.  2735). 


FATTY   ACIDS.  37 


duced,     but,     instead,    linusic     acid,     a     hexoxystearic     acid, 
C17H29  |  (^Q1^.     This  last  melts  at  203°-205°,  and  furnishes  a 

hexacetyl  derivative,  C17H29  j  '^Q    ^j|    '6.   Hence  the  pre-  exist- 


ence of  linolenic  acid  in  the  original  mixture  of  acids,  as 
the  source  of  the  crystallisable  hexabromide,  would  seem  to  be 
pretty  clearly  demonstrated. 

The  existence  of  an  isomeric  modification  of  linolenic  acid, 
isolinolenic  acid,  is  inferred  from  the  fact  of  a  noncrystalline  hexa- 
bromide being  apparently  produced  by  the  addition  of  bromine 
to  the  original  mixed  acids,  together  with  the  circumstance 
that  on  oxidising  the  mixture  by  alkaline  permanganate  there 
are  formed  (in  various  relative  proportions,  according  to  the 
kind  of  drying  oil  operated  on)  not  only  dioxystearic  acid  (due 
to  oleic  acid  contained),  sativic  acid  (tetroxystearic  acid,  due 
to  linolic  acid,  C18H32O9),  and  linusic  acid  (due  to  linolenic  acid), 
but  also  another  hexahydroxylated  stearic  acid,  isolinusic  acid, 
isomeric  with  linusic  acid;  this  melts  at  173°-175°,  and  furnishes 

a  hexacetyl  derivative,  C17H.,9  <  ^pA  jL,4  ,  resembling  that 
obtained  from  linusic  acid,  but  less  soluble  in  ether. 


OXYACETIC   (GLYCOLLIC)    FAMILY   OF   FATTY 
ACIDS. 

The  members  of  this  family  (general  formula,  CmH2in  <  QQ  OH/ 

hitherto  recognised  as  normal  constituents  of  fats,  oils,  waxes, 
£c.,  are  but  few  in  number.  Carnauba  wax  has  been  found  by 
Stiircke  *  to  contain  a  small  quantity  of  a  substance  simultane- 
ously possessing  the  properties  of  an  alcohol  and  an  acid,  indi- 

f  OTT      OTT 
cated  by  the  formula  C19H38  ]  QQ  2  j)  JT    ;    when   this   is   heated 

with  soda  lime,  it  forms  an  acid  of  the  oxalic  family  with  evolu- 
tion of  hydrogen. 

CHo.OH     ,     ov    ^TT  n      TT        fCO.ONa       .       OTT  TT   n 

-  ^ 


The  essential  oil  of  Angelica  Arcliangelica  contains  (probably 
as  some  form  of  compound  ether)  an  acid  which  appears  to  be 

(  OTT 

oxymyristic  acid,\  C13H26  \  ^  OH,  fusing  at  51°,  and  yielding 


(  O    f  TT  O 

a   benzoyl  oxymyristic  acid  C13H26  <  ^A    5^j|    ,  fusing    at    near 

*  Annahn  der  Chemie.,  223,  p.  283;  also  Journal  Soc.  Chem.  Industry, 
1884,  p.  448. 
t  R.  Muller,  JBerichte  Deut.  Chem.  Ges.,  1881,  vol.  xiv.,  p.  2476. 


38  OILS,    FATS,    WAXES,    ETC. 

68°.  An  oxymyristic  acid  apparently  identical  with  this  is 
obtainable  from  myristic  acid  by  brominating  and  treating  the 
resulting  monobromomyristic  acid  with  caustic  soda. 

By  similar  processes  palmitic  acid  yields  oxypalmitic  acid  and 
stearic  acid,  oxystearic  acid.  Of  this  latter  body,  moreover,  more 
than  one  isomeric  modification  is  known  ;  thus  M.  C.  &  A.  Say- 
tzeff  found  *  that  a-oxy  stearic  acid  is  obtained  when  isoleic  acid 
(m.p.  45°)  is  combined  with  hydriodic  acid  so  as  to  form  an 
iodostearic  acid,  and  the  product  treated  with  silver  hydroxide  ; 
while  fi-oxystearic  acid  is  similarly  obtained  from  ordinary  oleic 
acid  ;  the  reaction  in  each  case  being  expressed  by  the  equations 

Oleic  Acid.  Iodostearic  Acid. 

Ci8H3402         +         HI  CI8H35IOo 

Iodostearic  Acid.  Oxysteavic  Acid. 

C18H35I02     +     AgOH     =     Agl     +     C18H3a(OH)02 

a-oxystearic  acid  melts  at  80°-82°  and  distils  unchanged  ; 
Avhilst  /3-oxystearic  acid  breaks  up  on  heating  into  water  and 
ordinary  oleic  acid  — 

Oxystearic  Acid.  Oleic  Acid. 

C1SH35(OH)02        =        H2O         +         CJ8H3402 

The  same  two  acids  are  also  obtainable  by  treating  isoleic  acid 
with  sulphuric  acid,  when  combination  takes  place  as  the  forma- 
tion of  two  isomeric  oxystearosulphuric  acids,  which  by  the 
hydrolytic  action  of  water  are  decomposed  into  sulphuric  acid 
and  oxystearic  acids,  thus  — 

Sulphuric  Oxystearo- 

Isoleic  Acid.  Acid.  sulphuric  Acid. 

C17HS3.CO.OH     +     H2S04     =     GirH 

Oxystearo-  Oxystearic  Sulphuric 

sulphuric  Acid.  Water.  Acid.  Acid. 

Ci7H34k    3        +      H20     =     Ci7H34  +     H2S04 


the  two  reactions  jointly  are  consequently  tantamount  to  the 
addition  of  water  611  to  isoleic  acid  — 

Isoleic  Acid.  Oxystearic  Acid. 

r    TI       PIT     PIT    rr»  ryprj-TT  f\\  =  Ci5H31  -CH2~CH.OH  -CO.  OH 
C15M31-CH  lioUj   _Cl5H31-CH.OH-CH2-CO.OH 

The  a  or  the  (3  acid  thus  results  according  as  the  hydroxyl  group 

becomes  added  to  the  penultimate  or  antepenultimate  carbon. 

Geitel  finds  t  that  when  ordinary  oleic  acid  is  thus  treated 

*  Jahresbericht,  1888,  p.  1916  :  from  Journal  pr.  Chemie,  [2]  37,  p.  269. 
t  Journal  Soc.  C/iem.  Industry,   1888,  p.    218  ;  from  Journal  f.  prakt. 
Chemie,  [2]  37,  p.  53. 


FATTY    ACIDS.  39 

with  sulphuric  acid,  besides  the  a-oxystearic  acids  above  described 
a  y-oxystearic  acid,  C14H2g  -  .  CH .  OH  -  CH2  -  CH2  -  CO  .  OH, 
is  produced,  which  readily  forms  an  "  inner "  anhydride,  stearo- 
lactone, CUH29  -  CH  -  CH2  -  CH2  -  CO.  This  anhydride  is 
produced  whenever  a  salt  of  y-oxystearic  acid  is  decomposed  by 
.a  mineral  acid  ;  if  the  acid  solution  be  cautiously  neutralised  in 
the  cold  by  an  alkali,  the  stearolactone  remains  unaltered,  and 
may  be  obtained  by  dissolving  out  with  ether  or  benzoline, 
and  thus  separated  from  any  other  accompanying  fatty  acids 
set  free  by  the  mineral  acid,  but  retained  by  the  subsequent 
addition  of  alkali.  When  boiled  with  alcoholic  potash,  however, 
potassium  /-oxystearate  is  produced. 

Stearolactone.  Potassium  Oxystearate. 

C17H34J~      I  +        HOK         +        C17H34|°** 


Processes  for  detecting  and  estimating  stearolactone  in  mix- 
ture with  free  fatty  acids,  &c.,  are  founded  on  these  reactions. 
Stearolactone  is  readily  soluble  in  alcohol,  ether,  and  light 
petroleum  spirit;  it  crystallises  in  needles  melting  at  51°;  it 
is  formed  in  somewhat  large  quantity  when  oleic  acid  is  heated 
with  zinc  chloride  and  the  product  treated  with  water  (Benedikt), 
probably  by  reactions  analogous  to  those  taking  place  under  the 
influence  of  sulphuric  acid  (vide  Chap,  vn.) 

An  anhydride  isomeric  with  stearolactone  is  derived  from 
a-oxystearic  acid  by  the  action  of  hydrochloric  acid  thereon  (C. 
and  A.  Saytzeff)  in  accordance  with  the  equation — 

OP    TT        f  OH  OTJ  n  r<    TT       f  CO  •  0 1    /-i    TT 

2C17H34   |  CQ    QH  2H20     +     C17H34  |  Q    co  |  C17H34 

This  substance  is  fluid  at  the  ordinary  temperature  and  does  not 
solidify  011  chilling  ;  it  combines  with  neither  bromine  nor  iodine 
(Hiibl's  reagent),  but  on  heating  with  caustic  potash  becomes 
wholly  converted  into  potassium  oxystearate ;  on  acidifying  the 
product  a-oxystearic  acid  is  set  free,  and  not.  an  anhydride,  as 
in  the  case  of  stearolactone. 


OXYACRYLIC  (KICINOLEIC)  FAMILY  OF 
FATTY  ACIDS. 


f 

The  acids  of  general  formula  CmH2m_2-!  QQ   QJJ    obtained  by 

the   sapoiiification   of  fixed   oils,    &c.,   are  not  very  numerous, 

{  OH 

ricinoleic  acid,  CirH32  \  ^Q    OH  ,  being  the  only  one  as  yet  known 


40  OILS,    FATS,    WAXES,  ETC. 

with  certainty  ;  castor  oil,  and  to  a  lesser  extent  some  other  oils, 
contain  ricinolein,  the  glyceride  of  ricinoleic  acid.  To  isolate 
the  acid,  castor  oil  is  saponified  with  concentrated  caustic  potash 
solution,  and  the  resulting  soap  decomposed  by  heating  for  a 
short  time  with  hydrochloric  acid ;  the  separated  acids  are 
washed  with  water  several  times,  and  then  cooled  to  0°,  or  some- 
what lower ;  the  mass  solidifies  and  is  subjected  to  pressure, 
first  gentle  then  stronger,  so  as  to  squeeze  out  liquid  matters, 
the  temperature  being  gradually  raised  to  10°- 12°.  If  any  con- 
siderable quantity  of  unsaponified  oil  is  mixed  with  the  free  fatty 
acids,  their  solidification  by  chilling  is  greatly  hindered,  a  result 
also  brought  about  by  the  presence  of  bye -products  formed  by  the 
action  of  the  air  on  the  free  fatty  acids  ;  wherefore  the  saponify- 
ing and  decomposing  operations,  <kc.,  should  be  conducted  as 
rapidly  as  possible.  Thus  purified  ricinoleic  acid  fuses  at 
16°-17°,  the  phenomenon  of  superfusion  being  strongly  shown 
by  the  liquid  acid,  which  usually  does  not  solidify  again  until 
considerably  chilled. 

When  castor  oil  is  heated,  the  ricinoleic  acid  present  therein 
as  glyceride  breaks  up  into  oenanthol  and  hendecenoic  acid, 
thus — 

iiicinoleic  Acid.  (Enanthol.         Hendecenoic  Acid. 

<-1i8H3403     =     C7H]40     +     CnH2002 

Free  ricinoleic  acid,  however,  when  heated  does  not  split  up  in 
this  way  at  all,  neither  does  it  distil  unchanged  even  under 
greatly  diminished  pressure — below  15°  rnm.  An  acid  distillate 
passes  over  at  about  250°,  which  on  rectification  furnishes  aiiacid 
boiling  at  about  230°  at  15  mm.  ;  and  giving  numbers  correspond- 
ing with  the  formula  C]8H32O2  (p.  36),  whence  it  would  seem  that 
water  is  thus  split  off  from  ricinoleic  acid  yielding  a  linolic  acid 
isomeride.  Hydriodic  acid  and  phosphorus  convert  ricinoleic  acid 
into  stearic  acid ;  heating  with  caustic  potash  forms  a  secondary 
decylic  alcohol,  C10H21  (OH),  and  sebacic  acid,  C8H16  (CO.OH)2, 
from  which  reactions  the  structure  would  seem  probable 
CH3  -  (OH2)5  -  CH .  OH  -  CH  =  OH  -  (CH2)S  -  CO .  OH.  Alka- 
line permanganate  oxidises  ricinoleic  acid  to  trioxystearic  acid 
(Dieff  and  Reformatsky). 

By  the  action  of  nitrous  acid  ricinoleic  acid  is  converted  into 
ricinelaidic  acid  melting  at  52°-53°  ;  on  heating  under  diminished 
pressure,  this  is  decomposed  much  more  slowly  than  ricinoleic 
acid.  Oxidation  by  means  of  nitric  acid  readily  converts  it 
into  normal  heptoic  acid,  whilst  alkaline  permanganate  forms 
trioxystearic  acid.  According  to  Hazura  and  Griissner, 
two  different  trioxystearic  acids  are  formed  when  ricin- 
oleic acid  is  thus  oxidised,  respectively  melting  at  140°-142° 
(trioxystearic  acid),  and  at  110°-111°  (isotrioxy  stearic  acid);  from 
which  they  infer  the  presence  in  castor  oil  of  two  isomeric  acids 


FATTY    ACIDS.  41 

(ricinoleic  and  isorlcinoleic  acids  respectively).  Both  of  these 
trioxy  acids  form  triacetyl  derivatives,  ClTH.j:,  S  QQ  ()H3  > 

and  both  are  reducible  to  ordinary  stearic  acid  by  means  of 
hydriodic  acid  ;  the  latter  is  present  to  the  extent  of  about  twice 
as  much  as  the  former. 

Isomerid.es  of  Ricinoleic  Acid.  —  On  heating  barium  ricin- 
oleate  Krafft  obtained  a  residue  from  which  an  acid  termed  by  him 
ricinic  acid  was  isolated,*  apparently  isomeric  with  ricinoleic 
acid;  this  melted  at  81°,  and  distilled  unchanged  at  250°-252° 
under  15  mm.  pressure  ;  by  oxidation  it  yielded  normal  heptok? 
acid. 

Rapic  Acid.  —  Reimer  and  Will  have  obtained  from  colza  oil  a 
liquid  acid,  C1SH34O3,  differing  considerably  from  ricinoleic  acidr 
especially  in  not  forming  a  solid  elaidic  acid  with  nitrous  acidf 
and  in  not  yielding  sebacic  acid  on  fusion  with  potash.  This  is 
isolated  by  means  of  the  zinc  salt  which  is  soluble  in  ether, 
whereas  zinc  erucate  is  insoluble  therein.  ;  by  decomposing  the 
recrystallised  salt  (melting  at  78°)  by  tartaric  acid,  and  well 
Avashing  with  water,  rapic  acid  is  obtained  as  a  fluid  mass,  not 
solidifying  even  when  considerably  chilled. 

Oxyoleic  Acid.  —  When  the  dibromide  of  oleicacid  (dibromo- 
stearic  acid)  is  treated  with  silver  hydroxide  it  forms  oxyoleie 
acid,  apparently  in  consequence  of  the  removal  of  the  elements  of 
HBr,  forming  bromoleic  acid,  and  the  action  thereon  of  silver 
hydroxide,  thus  — 

Eromoleic  Acid.  Oxyoleic  Acid. 

C17H,2Br.CO.OH     +     AgOH     =     AgBr      +      C17H 


The  same  product  results  by  first  converting  the  dibromide 
into  bromoleic  acid  by  means  of  potash  and  then  acting  upon 
this  with  silver  hydroxide  (Overbeck).  Oxyoleic  acid  is  a  thick 
liquid  at  ordinary  temperatures  but  solidifies  on  chilling  ;  by 
boiling  with  caustic  potash  it  takes  up  water,  forming  a  dioxy- 
stearic  acid,  melting  at  126°.  J 

r    TT     /OH  p    „    /(OH)2 

Li7M32|co    OH  Ll7H33lCO.OH 

{OH 
C1O     OH  '  *S 

formed  when  the  dibromide  of  hypogaeic  acid  is  treated  with 
silver  hydroxide  (Schroder)  ;  as  with  oleic  dibromide,  the  action 
probably  takes  place  in  two  stages,  the  elements  of  HBr  being 

*  Berichte  d.  Deut.  Chem.  Ges.,  1888,  vol.  xxi.,  p.  2730. 

t  Berkhte  d.  Deul.  Chem.  Ges.,  1887,  vol.  xx.,  p.  2385. 

l^  Later  experiments  by  Saytzeff  indicate  that  this  acid  is  identical  with 
the  dioxystearic  acid  melting  at  136'5,  obtained  by  him  by  oxidation  of 
oleic  acid  by  alkaline  permanganate  (p.  30). 


42  OILS,    FATS,    WAXES,    ETC. 

first  removed,  forming  bromohypogseic  acid,  C1GH20Br02,  and  this 
being  then  converted  into  the  oxyacid,  thus  — 

Cl5H28Br  .  CO  .  OH     +     AgOH     =     AgBr     +     ClfiH28{cO.OH 

It   melts   at  34°,    and  by  boiling  with  caustic  potash   solution 
takes  up  the    elements    of  water   forming    dioxypalmitic   acid, 

usin    at  115°' 


When  oleic  acid  is  heated  to  200°  and  a  stream  of  air  blown 
through  (as  in  the  preparation  of  "  blown  oils,"  it  absorbs 
oxygen  and  becomes  largely  converted  into  an  oxyoleic  acid 
(Benedikt  and  Ulzer).  The  relationships  of  the  oxidised  oleins 
and  similar  substances  contained  in  blown  oils  to  ricinoleic 
glyceride  (castor  oil)  have  not  been  fully  studied,  but  appa- 
rently there  is  a  considerable  degree  of  similarity  between 
them.  The  same  remark  applies  to  the  oxidised  acids  formed 
when  oils  and  fats  are  kept  for  long  periods  of  time,  so  as  to 
.absorb  oxygen  largely  from  the  air  spontaneously.  On  the 
other  hand,  when  drying  oils  are  exposed  to  the  air  in  thin 
films,  so  as  to  "  dry  "  up  to  solid  varnishes,  they  absorb  oxygen  ; 
when  the  absorption  attains  its  maximum,  the  increment  in 
weight  is  tolerably  close  to  that  corresponding  with  the  weight 
of  iodine  capable  of  being  taken  up  by  the  original  oil, 
whilst  the  capacity  for  absorbing  iodine  decreases  pari  passu 
with  the  oxidation.  It  would,  therefore,  seem  that  the  tendency 
of  atmospheric  oxidation  of  drying  oils  is  to  produce  less  "  un- 
saturated  "  oxidation  products  than  the  original  substances  ; 
whence  by  analogy  in  the  case  of  oleic  glyceride,  it  would 
seem  probable  that  saturated  acids  are  formed  thus,  rather 
than  uiisaturated  acids  like  oxyoleic  acid.  A  product  has  been 
recently  introduced  into  the  market  under  the  name  of  "  oxy- 
oleate,"  for  use  as  a  "  Turkey  red  oil,"  obtained  by  the  action 
•of  sulphuric  acid  on  certain  oils,  and  decomposition  of  the 
•compound  sulphuric  acid  formed  by  heat  (vide  Chap,  vn.)  The 
precise  chemical  nature  of  this  substance  does  not  seem  to 
have  been  closely  investigated  as  yet;  presumably  it  chiefly 
consists  of  an  oxystearic,  rather  than  an  oxyoleic  acid,  since 
by  hydrolysis  the  former  and  not  the  latter  results  from  the 
sulphuric  acid  compound  of  oleic  acid  (supra,  p.  38). 

AnUydrodioxystearic  Acid.  —  When  dioxystearic  acid  (melting 
point  136°-5)  is  distilled  under  diminished  pressure  (100  to 
180  mm.)  it  breaks  up  into  water,  and  a  monobasic  acid,  isomeric 
with  ricinoleic  acid,  melting  at  77°-79°,  and  solidifying  at 
66°-69°.*  From  its  mode  of  formation  this  product  is  obviously 

f  -=  O 
indicated  by  the  formula,  C^Hgg  •!   _  /-JQ    QJT  >  being  a  saturated 

-compound,  not  containing  alcoholiform  hydroxyl  like  ricinoleic  acid. 
*  A.  Saytzeff,  /.  prakt.  Chem.  [2],  vol.  xxxiii.,  p.  300. 


FATTY    ACIDS. 


43 


It  is  not  improbable  that  the  rapic  acid  above  mentioned 
has  an  analogous  constitution,  since  the  low  acetyl  number  pos- 
sessed by  colza  oil  renders  it  unlikely  that  any  large  quantity 
of  a  glyceride  of  a  hydroxylated  acid  is  present  therein  (Chap,  vin.) 


POLYHYDEOXYLATED  STEAKIO  ACIDS. 

A  number  of  acids  are  known,  related  to  stearic  acid  in  that 
they  are  derived  therefrom  by  the  replacement  of  two  or  more 
hydrogen  atoms  by  hydroxyl  groups — i.e.,  by  a  further  continu- 
ance of  the  action  by  means  of  which  oxystearic  acids  may  be 
regarded  as  derived  from  stearic  acid.  These  polyhydroxylated 
derivatives  are  all  expressed  by  the  general  formula, 

CirE35_n(OH)n.CO.OH 

When  11  =  1,  some  modification  of  oxystearic  acid  results  ;  when 
n  =  2,  a  dioxystearic  acid  (higher  homologue  of  glyceric  acid) ; 
similarly,  when  n  =  3,  4,  or  6,  trioxy-,  tetroxy,  and  hexoxy- 
stearic  acids  respectively  result. 

The  following  table  gives  the  principal  sources  and  melting 
points  of  these  acids,  the  usual  mode  of  production  being  gentle 
oxidation  of  the  acid  serving  as  source  with  alkaline  perman- 
ganate : — * 


Name. 

Formula. 

Source. 

Melting 
Point. 

Solidifying 
Point. 

Dioxystearic  acid, 

Ci7H33(OH)2.CO.OH, 

Oleic  acid, 

136°  -5 

119°-  122° 

Isodioxy  stearic  acid, 

Do., 

Elaidic  acid, 

99°-  100° 

85°-86° 

Do., 

Do., 

Isoleic  acid, 

77°-78° 

64°-66° 

Trioxystearic  acid, 

C17H32(OH)3.CO.OH, 

Castor  oil, 

140°-  142° 

... 

Isotrioxystearic     \ 
acid,                       J 

Do., 

Do., 

110°-1110 

... 

/3-isotrioxysteario  1 
acid,                     J 

Do.,               { 

Eicinelaidic 
acid, 

114°-  115° 

... 

Sativic  acid             ) 

(Tetroxystearic    > 

Cl7H3l(OH)4.CO.OH, 

Linolic  acid, 

173° 

... 

acid),                      ) 

Linusic  acid            j 

(Hexoxystearic    > 

C17H2o(OH)4.CO.OH, 

Linolenic  acid, 

203°-205° 

... 

acid),         .         .  ) 

Hemp     seed  » 

Isolinusic  acid         i 

oil,        &c.,  J 

(Isohexoxy- 
stearic  acid),         ) 

Do., 

(supposed 
isolinolenic  \ 
acid), 

173°-17C° 

... 

i 

*  A  dioxystearic  acid  (melting  point  136°)  is  also  obtainable  in  small 
quantity  by  the  action  of  silver  hydroxide  on  the  dibromide  of  oleic  acid 
(p.  30);  also  by  the  hydration  of  oxyoleic  acid  (p.  41).  Oxyhypog;eic  acid 


44  OILS,    FATS,    WAXES,    ETC. 

A  remarkable  rule  is  uniformly  followed  in  all  cases  where 
unsaturated  fatty  acids  are  thus  oxidised  —  viz.,  that  a  number 
of  hydroxyl  groups  is  always  taken  up  sufficient  to  form  a  satu- 
rated polyoxy  acid.*  Thus  in  the  case  of  the  oxystearic  acids, 
unsaturated  acids  of  form  C17H33.CO:OH  (oleic,  isoleic,  and 
elaidic  acids),  take  up  two  hydroxyl  groups  forming  three  dif- 

ferent dioxystearic  acids,  C17Ho3  <  /s/-^    OTT  '>  similarly  ricinoleic 

(  OTT 

and  riciiielaidic  acids  of  form  C17H.J2  <  ^^    ~TT    take   up   2  hy- 

droxyl groups,  producing  two  trioxystearic  acids,  C17H32  <  LQ  Q\T. 

In  the  same  wray  hendecenoic,  hypogseic,  and  erucic  acids  take  up 
2  hydroxyl  groups  giving  rise  to  dioxyhendecoic,  dioxypalmitic, 
and  dioxybenic  acids  respectively.  On  the  other  hand,  linolic 
acid,  C-l7H31  .  CO  .  OH,  takes  up  4  hydroxyl  groups,  producing 

sativic  (tetroxystearic)  acid,  C17H.U  <  X/-\  ATT  ',  whilst  linolenic 
acid,  Cl7H09  .  CO  .  OH,  takes  up  6  groups,  producing  liimsic 
(hexoxystearic)  acid,  C17IL0  < 


The  above  rule  appears  to  be  only  a  particular  case  of  a  con- 
siderably wider  principle  applying  also  to  hydrocarbons  and 
alcohols,  etc.,  of  unsaturated  character,  which  may  be  put  in  the 
form  of  the  following  theorem  :  —  - 

With  substances  containing  the  group  —  CH  =  CH  —  (or  cer- 
tain groups  thence  derived,  -  OR  =  CH,  -  and  —  CR  =  CS  —  , 
where  R  and  S  are  monad  alkyl  radicles),  the  effect  of  oxidising 
agents  of  not  too  energetic  a  character  is  to  cause  the  addition  of  tico 
hydroxyl  radicles  so  as  to  form  the  group  -  CH.  OH  -  CH.  OH  - 
(or  the  derived  group  -  CR.OH  -  CS.OH  -  ),  this  action 
occurring  twice  over  if  two  groups  —  CH  =  CH  —  are  present, 
thrice  over  if  three  groups  are  present,  and  so  on. 

Thus  Wagner  has  found  *  that  olefmes  are  readily  transformed 
into  glycols  by  means  of  potassium  permanganate  in  virtue  of 
this  reaction;  alcohols  of  unsaturated  character  (allylic  series) 
similarly  become  glycerols  ;  hydrocarbons  containing  the  group 
—  CH  =  CH  -  twice  (e.g.,  diallyl)  become  erythrols,  and  so  on. 
Glycerol  itself  is  thus  obtainable  from  allylic  alcohol. 

(from  dibromide  of  hypogseic  acid)  behaves  similarly,  forming  a  dioxy- 
palmitic acid,  melting  point  115°.  A  dioxypalmitic  acid  was  obtained  by 
Groger  (inter  alia)  by  the  direct  oxidation  of  palmitic  acid  with  alkaline 
permanganate.  Two  dioxybenic  odds  are  known,  respectively  derived 
from  the  dibromides  of  erucic  and  brassic  acids  (p.  29),  and  melting  at 
132°-  133°  and  9S°-99°. 

*  Hazura  &  Griissner,  Journal  Soc.  Chem.  Industry,  1888,  p.  506;  from 
Monatsh.  Chem.,  vol.  ix.,  p.  180. 

t  Berichte.  d.  Dent.  Chem.  Ges.,  1888,  21,  pp.  1230  and  3343. 


FATTY    ACIDS.  45 

111  all  probability  the  first  action  taking  place  is  the  direct  com- 
bination of  oxygen  in  the  same  way  as  the  combination  of  bro- 
mine or  iodine,  thereby  forming  a  substance  containing  the  group 
— CH  —  CE  —  CRX 

O,  or  the  derived  groups         |       j>O      or  I/O; 

— CH  —  CH/  — C8 

this  product  then  assimilating  water  whilst  nascent. 

Tims,  for  example,  oleic  acid,  C17H.,., .  CO  .  OH,  may  be  supposed 

to  combine  with  oxygen,  forming  C17H33  %  ~  ~Q  QTT  ;  by  tak- 
ing up  water  this  immediately  produces  dioxystearic  acid, 

(OH 
CrH33  lOH         ;    whilst    linolic    acid,   C.-H.^  .  CO .  OH,  simi- 

(CO.OH 

i =0 

larly  first  forms  CrH,r    =O  ,  which  by  taking  up  2H0O 

( -CO. OH 

OH 
OH 

forms  tetroxystearic  acid  (sativic  acid),  Cl5.Hgl^  OH 

OH 
^CO.OH 

Tn  the  case  of  the  stearolic  acid  and  its  homologues  obtained 
from  acrylic  acids  by  the  bromine  reaction  (addition  of  Br.7  and 
removal  of  2HBr,  p.  31),  the  effect  of  oxidation  stops  short  at 
the  first  stage,  2  atoms  of  oxygen  being  added  on  forming  a  satu- 
rated compound  which  does  not  take  up  water.  Thus  stearolic 

(  =° 
acid,  CrH.n  .  CO  .  OH,  forms  stearoxylic  acid,  ^-H^  -    =  O 

(  -  CO  .  OH 

melting  at  84°-86°,  by  the  direct  action  of  nitric  acid  (Overbeck),^ 
or  by  means  of  alkaline  permanganate  (Hazura  &  Griissner). 
Similarly  palmitolic  acid  (from  hvpogseic  dibromide),  gives  the 

*    I  =  ° 

analogous  pal mito.icyl ic  acid,  CirH.>-<    =O  ,  melting  at  67° 

"  (  -  CO  .  OH 

(Schroeder) ;  and  benolic  acid  (from  erucic  dibromide)  gives  ben- 

f  =  0 
oxylic  acidj    melting   at    90°-91°,  C91H80^=O  (Hauss- 

(-CO. OH 

knecht). 

•;-  Overbeck  (Annakn.  Chem.  P/iarm.,  1866,  140,  p.39)  found  that  the  stear- 
oxylic acid  thus  prepared  would  not  combine  with  bromine,  and  concluded 
that  the  4  affinity  units  which  in  stearolic  acid  are  capable  of  combining 
with  Br4,  are  saturated  by  oxygen  when  stearolic  acid  is  converted  into 
stearoxylic  acid. 

t  Termed  " dioxybenolic  acid"  by  its  discoverer. 


46  OILS,    FATS,    WAXES,    ETC. 

By  the  action  of  heat  (distillation  in  vacuo)  dioxystearic  acid 
(melting  at  136°),  loses  water  forming  an  anhydro  derivative  still 
possessing  the  characters  of  a  monobasic  acid  (Saytzeff);  obviously 
thus — 

(OH  (  = O 

C17HS8    OH  =     H20      +      C17HoJ 

( CO . OH  (   -  CO . OH 

the   reaction   being   the   converse    of  the  second   stage  in   the 
hydroxylation  of  unsaturated  acids  as  above. 


GENERAL    PHYSICAL    CHARACTERS.  47 


§  2.  Physical  Properties  of  Oils,  Fats, 
Waxes,  &c. 


CHAPTER  IV. 

GENERAL  PHYSICAL  CHARACTERS. 
PHYSICAL  TEXTURE  AND  CONSISTENCY. 

THE  physical  consistency  of  a  fixed  oil — butter,  fat,  or  wax — 
depends  entirely  upon  the  temperature  ;  when  this  is  sufficiently 
raised  all  are  fluid  oils  ;  but  at  lower  temperatures,  according  to- 
the  nature  of  the  substance,  more  or  less  complete  solidification 
is  brought  about.  In  many  cases,  natural  fixed  oils,  &c.,  are 
mixtures  of  different  glycerides,  &c.,  the  melting  points  of  which 
are  different ;  accordingly,  at  temperatures  somewhat  below  the 
melting  point  of  the  least  fusible  constituent,  this  more  or  less 
completely  solidifies,  whilst  the  other  constituents  remain  liquid, 
thus  giving  rise  to  pastiness  or  buttery  texture.  Substances  of 
practically  uniform  composition  (i.e.,  consisting  essentially  of  only 
one  kind  of  compound)  generally  exhibit  a  fairly  sharply  defined 
melting  point  when  the  temperature  is  sufficiently  raised;  but  this 
is  not  the  case  with  mixtures ;  accordingly,  considerably  different 
temperatures  will  be  registered  as  the  fusing  points  of  such  sub- 
stances if  different  methods  be  employed,  depending,  for  instance, 
in  one  case,  upon  the  production  of  a  considerable  degree  of 
softness  only ;  in  another,  upon  the  complete  liquefaction  of  all 
the  constituents  ;  and  so  011  (vide  p.  61,  63). 

Even  the  most  fluid  oils  possess  to  a  greater  or  lesser  extent 
the  property  of  viscosity,  or  resistance  to  flow,  due  to  the  greater 
or  lesser  degree  of  cohesion  between  the  constituent  particles  of 
the  liquid.  When  the  smooth  surfaces  of  two  solids  are  smeared 
or  wetted  with  a  viscous  fluid  and  applied  to  one  another,  a, 
varying  degree  of  force  will  be  requisite,  according  to  circum- 
stances, in  order  to  enable  one  surface  to  glide  over  the  other. 
The  amount  of  force  requisite  in  any  given  case  largely  depends  on 
the  viscosity  of  the  fluid  employed;  to  diminish  this  force  is  the 


4-S  OILS,    FATS,    WAXES,    ETC. 

main  object  of  lubrication  in  the  case  of  machinery,  and  in  conse- 
quence the  determination  of  the  relative  lubricating  powers  of 
different  materials  (lubricating  oils,  &c.)  is  an  important  point  in 
the  valuation  for  such  purposes  of  different  fixed  oils,  mixtures 
of  these  and  mineral  oils,  and  such  like  substances  employed  for 
the  purpose.  It  is  found  that  the  rate  at  which  a  given  fluid 
flows  through  an  orifice  of  standard  dimensions  is  in  many  cases 
&  fair  measure  of  its  lubricative  powers  ;  whence  the  determina- 
tion is  frequently  made  of  the  rate  of  efflux  of  lubricating  oils, 
«foc.,  as  compared  with  that  of  a  standard  fluid  (such  as  rape  oil), 
similarly  examined  in  the  same  apparatus  at  the  same  tempera- 
ture, the  value  deduced  being  generally  (but  by  no  means  cor- 
rectly) spoken  of  as  the  relative  viscosity  of  the  fluid  examined 
(vide  Chap,  v.) 

Cohesion  Figures. — When  a  drop  of  oil   is  allowed  to  fall 
gently  on  the  surface  of  water  in  a  basin  or  large  plate,  it  often 


Fig.  1. 

behaves  in  a  characteristic  way,  usually  first  spreading  out  into 
ii  thin  film  and  then  retracting  again.  It  has  been  suggested 
that  the  particular  forms  assumed  by  films  of  various  kinds 
(cohesion  figures)  are  sufficiently  well  defined  and  characteristic 
to  be  of  service  in  the  examination  of  oils  with  a  view  to 


GENERAL    PHYSICAL    CHARACTERS.  4$ 

detecting  adulteration ;  but  as  yet  little  success  has  attended 
experiments  in  this  direction.  Olive  oil  thus  treated  gives  a  fairly 
characteristic  result,  which  is  more  or  less  modified  by  various 
admixtures,  especially  sesame  oil.  Fig.  1  (Schadler)  represents 
the  different  cohesion  figures  exhibited  by  colza  oil  (A,  Brassica 
rapa ;  B,  Brassica  napus)  ;  poppy  seed  oil  (C  and  D) ;  sesame 
oil  (E) ;  arachis  oil  (F) ;  and  olive  oil  (G-). 

Taste  and  Odour. — When  in  a  state  of  absolute  purity, 
fixed  oils  have  usually  little  or  no  odour  or  taste ;  but  as  met 
with  in  commerce,  in  most  cases  traces  of  sapid  or  odorous 
matters  accompany  the  oil,  so  as  give  a  more  or  less  characteristic 
flavour  or  smell  thereto.  Essential  oils  of  the  oxidised  class,  on 
the  other  hand,  are  frequently  possessed  of  most  powerful  scent, 
although  the  hydrocarbons  therein  contained,  when  completely 
separated  from  all  traces  of  oxidised  matter  (by  heating  with 
sodium  or  other  similar  means),  are  generally  odourless  or  practi- 
cally so.  As  regards  the  edible  oils  and  fats,  a  considerable 
amount  of  their  value  depends  on  the  delicacy  and  purity  of  the 
flavour ;  thus  genuine  olive  oil  is  esteemed  far  more  highly  by 
connoisseurs  than  refined  cotton  seed  oil,  groundnut  oil,  and 
similar  substances  with  which  the  ordinary  commercial  article  is 
often  largely  intermixed,  although,  from  the  nutritive  point  of 
view,  these  latter  are  probably  quite  equal  in  value  to  the  pure 
product  of  the  olive.  Similarly,  the  commercial  value  of  butter 
is  largely  affected  by  its  flavour  and  freedom  from  all  trace  of 
rancidity  or  rankness  ;  and  analogous  remarks  apply  to  lard. 
The  difficulty  of  removing  all  matters  communicating  unpleasant 
odour  or  taste  to  many  varieties  of  fatty  or  oily  matter  often 
prevents  these  being  used  for  dietetic  purposes  to  any  consider- 
able extent,  at  any  rate  by  civilised  nations  ;  in  the  case  of 
some  materials — e.g.,  cod  liver  oil — such  removal  is  practically 
impossible  without  more  or  less  interfering  with  the  special 
characters  and  qualities  of  the  substance.  Palm  oil  has  generally 
a  peculiar  smell,  recalling  that  of  violets,  and  for  certain  purposes 
the  possession  of  this  odour  is  valuable — e.g.,  in  the  prepara- 
tion of  certain  kinds  of  scented  soaps.  The  development  of 
"  rancidity  "  in  fixed  oils  on  keeping  is  in  most  cases  due  to 
the  presence  in  small  quantity  of  mucilaginous  or  albuminous 
matters  which  undergo  chemical  changes  (oxidation,  or  decom- 
position, &c.)  in  the  course  of  time  ;  accordingly,  the  purification 
and  refining  of  crude  oils,  &c.,  for  the  purpose  of  removing  these 
ingredients  is  often  a  highly  important  operation. 

Colour.— Expressed  vegetable  fixed  oils  sometimes  possess  a 
greenish  shade,  due  to  the  presence  of  chlorophyll ;  as  a  general 
rule,  coldpressed  oils  of  all  kinds,  prepared  from  fresh  substances, 
are  almost  white ;  whilst  oils  subsequently  expressed  by  the 
aid  of  heat,  especially  from  materials  that  have  been  stored  some 
time,  are  generally  darker  in  tint,  the  hue  varying  from  a 

4 


50 


OILS,    FATS,    WAXES,    ETC. 


light  straw  yellow  to  a  light  or  even  dark  brown.  Palm  butter 
usually  contains  a  dark  orange  red  colouring  matter,  different 
from  chlorophyll ;  similar  substances  appear  to  be  present  in 
smaller  quantity  in  many  other  oils,  leading  to  the  necessity  for 
bleaching  them  for  certain  purposes.  The  refining  processes, 
whereby  mucilaginous  extractive  matters,  &c.,  are  removed, 
usually  serve  to  lighten  the  colour  also. 

The  addition  of  coloured  vegetable  expressed  oils  (containing 
chlorophyll,  &c.)  to  animal  oils,  such  as  sperm  oil,  may  sometimes 
be  detected  by  means  of  the  absorption  spectroscope  *  when  such 
adulteration  has  been  practised. 

The  phenomenon  of  fluorescence  does  not  appear  to  be.  exhibited 
by  refined  vegetable  or  animal  oils  free  from  substances  possessed 
of  fluorescent  properties  (such  as  aesculin,  occasionally  found  in 
horse-chestnut  oil);  on  the  other  hand,  products  of  destructive 
distillation  (coaltar  and  rosin  oils,  tfec.)  often  exhibit  this  peculi- 
arity, so  that  admixtures  of  such  hydrocarbons  with  more  expen- 
sive vegetable  and  animal  oils  may  sometimes  be  thus  detected. 

Action  of  Polarised  Light. — The  majority  of  the  oils  and 
fats  in  common  use  have  so  little  action  of  a  marked  character 
on  polarised  light  that  little,  if  any,  definite  information  of  prac- 
tical value  is,  as  a  rule,  obtainable  by  means  of  such  light;  on 
the  other  hand,  adulteration  with  strongly  active  hydrocarbons 
(such  as  some  kinds  of  rosin  oils)  may  sometimes  be  detected  by 
means  of  the  polariscope. 

Bishop  has  obtained  the  following  values  for  a  length  of 
200  mm.  of  various  oils  in  a  Laurent  polarimeter;  the  other 
figures  annexed  are  from  Schadler  : — 


Bishop. 

Scbadler. 

Degrees. 

Degrees. 

{Linseed  oil, 

-  0-3 

-  0-2 

Nut  oil,     . 

-  0:3 

La&vogyrate,  • 

Apricot  oil, 
Arachis  oil, 

-  'o-4 

-  0-2 

-o-i 

Sweet  almond  oil, 

-  0-7 

-  0-2 

Colza  oil,  . 

-  1-6  to  -  2-1 

-  0-3 

Neutral,  or 
nearly  so, 

{Cotton  seed  oil, 
Poppy  seed  oil, 
Seal  oil,     . 

0 

0 

+  o-i 

0 

1'  Olive  oil,   . 

+  0-6 

+  0'2 

Cod  liver  oil, 

+  O'o  to  + 

0:7 

Dextrogyrate, 

Cold  pressed  sesame  oil, 

+  '3-1 

I  +  1-0  to  + 

1-1 

Hot 

-r  7  "2 

\ 

Castor  oil, 

+  9-8 

*  A  special  form  of  absorption  spectrum  colorimeter  for  this  sort  of 
examination  has  been  devised  by  T.  L.  Paterson  ;  vide  Journ.  ticc.  Chem. 
Industry,  1890,  p.  36. 


GENERAL    PHYSICAL    CHARACTERS. 


51 


Peter  finds  most  vegetable  oils  to  be  slightly  laevogyrate,  olive 
oil  being  an  exception,  so  that  admixtures  of  other  oils  may  some- 
times be  detected  by  the  rotation  being  left  handed  instead  of 
right  handed.  Croton  oil  and  castor  oil,  however,  are  compara- 
tively powerfully  dextrogyrate,  giving  values  exceeding  +  40°. 

Refractive  Index. — The  differences  in  refractive  power 
exhibited  by  different  oils  are  in  most  cases  hardly  sufficiently 
marked  to  render  this  property  of  much  value  in  discriminating 
one  from  the  other,  or  in  detecting  admixtures,  excepting  in  the 
case  of  a  few  oils  and  fats,  such  as  olive  oil  and  cow's  butter; 
thus  Strohmer  gives  the  following  values  for  the  I)  line  at  15°, 
and  Abbe  the  annexed  values  at  20°,  water  being  taken  as 
1-3330:— 


. 

Strohmer. 

Abbe. 

Olive  oil,     

1-4698  to  1-4703 

1  -4690 

1-4810 

Sesame  oil  (new), 

1  -4748 

,,       nine  years  old, 

1-4762 

Walnut  oil,          .... 

... 

1-491 

Cotton  seed  oil,            ... 

1-4732  to  1-4752 

\Crude,       1-4732 
)  Refined,    1-4748 

Rape  and  colza  oil, 

1-47-20  to  1-4757 

1-472  to  1-475 

Beechnut  oil,       .... 

1  -5000 

Cold  drawn  castor  oil, 

1  -4795 

\     i  -/too 

Hot  pressed           ,,               . 

1-4803 

Cold  drawn  linseed  oil, 

1-4835 

•4780 

Poppy  seed  oil,  .... 
Cod  liver  oil,       .... 

1-4783 
1-4800  to  1-4852 

•4670 
•4800 

Whale  oil  

•483    . 

Sperm  oil,            . 

•470 

From  which  it  appears  that  olive  oil  has  a  sensibly  lower  re- 
fractive index  than  the  others,  whilst  drying  oils  and  castor  oil 
exhibit  the  highest  values.  For  the  direct  determination  of  the 
refractive  index  of  oils  and  other  substances,  Abbe  and  Pulfrich 
have  devised  special  "  reiractometers." 

Amagat  and  Jean  *  have  also  constructed  an  "  oleorefracto- 
meter,"  whereby  the  refractive  power  of  a  given  oil  is  determined 
by  differential  comparison  with  a  sample  of  genuine  oil  taken  as 
standard',  a  positive  reading  denoting  increased  refractive  index 
and  vice  versd  ;  the  following  comparative  differential  values  have 
been  obtained  by  de  Bruijn  and  von  Leent  and  by  Jean  in  this 
way,  from  which  results  they  infer  that  the  refractive  powers  of 


*  Comptex  rendu*,  1889,  109,  p.  616  ;  see  also  Journ.  Soc.  Cliem.  Industry, 
1890,  pp.  113  and  218. 


52 


OILS,    FATS,    WAXES,    ETC. 


oils,  when  thus  tested,  are  capable  of  giving  more  information  as 
to  admixture  than  is  usually  supposed.  The  oil  to  be  examined 
should  be  previously  shaken  with  alcohol  to  dissolve  out  free 
fatty  acids ;  the  standard  of  comparison  was  a  sample  of  the 
purest  olive  oil  obtainable  : — 


de  Bruijn  and  v. 

Leent. 

Degrees. 

Degrees. 

Horse  foot  oil, 

-  12 

Sperm  oil,     . 
Neat's  foot  oil,      .... 

-  12 
3 

Sheep's  trotter  oil, 

0 

Olive  oil,       ..... 

0  to  +  2 

+  1  -5  to  +  2 

Almond  oil,           .... 

+  7 

+  6 

Arachis  oil,            .... 

+     3  to  -«-     4 

+  4  to  -f  5 

Colza  oil,      ..... 

+   15  to  H-  18 

+  16-5  to  +  17'5 

Sesame  oil,   ..... 

+  45 

+  17 

Cotton  seed  oil,    . 

+  20 

Maize  oil,     ..... 

+  27 

Poppy  seed  oil,      .... 
Whale  oil,    

... 

+  30 
+  30-5 

Hemp  seed  oil, 

+  33 

Castor  oil,     ..... 

+  37  to  +  46 

+  40 

Linseed  oil,            .... 

+  49  to  +  54 

+  53 

Cod  liver  oil, 

+  42 

Whale  oil,    

+  30-5 

Holde  has  obtained  the  following  average  results  with  this 
instrument,*  the  temperature  of  the  testing-room  being  close  to 
20°  throughout : — 


Limits  of  Index  of  Refraction. 

Mean  Index. 

Refined  rape  oil, 
Crude  rape  oil, 
Olive  oil,  ..... 

1-4722  to  1-4736 
1-4735  ,,  1-4760 
1-4670  ,.  1-4705 
1-4776  ,,  1-4980 

1-4735 
1  -4744 
1  '4698 
1  -4923- 

Resiu  oil,           .... 

1-5274  „  1-5415 

1  -5344 

The  presence  of  rape  oil  in  olive  oil  can  thus  be  detected  when 
any  considerable  amount  of  adulteration  has  been  made. 

In  the  case  of  butter,  Jean  claims  that  the  oleorefractometer 
is  capable  of  rendering  useful  service  in  the  laboratory.  Even  if 
butter  is  not  sufficiently  constant  in  refractive  power  to  enable  a 
decision  to  be  always  arrived  at  as  to  the  genuineness  or  other- 


Journ.  Soc.  Chem.  Industry,  1891,  p.  166. 


SOLUBILITY    IN    SOLVENTS.  53 

wise  of  a  given  sample  without  further  tests,  still  the  oleo- 
refractometer  indications  at  least  enable  a  rough  classification  of 
a  variety  of  samples  to  be  made,  viz.,  those  undoubtedly  spurious, 
those  doubtful,  and  those  probably  genuine.  The  normal  butter 
deviation  is  regarded  by  him  as  -  29°  to  —  31°,  averaging  —  30° ; 
if  higher  values  (32°— 36°)  are  observed,  admixture  with  palm  or 
cokernut  oil  is  probable;  slightly  lower  ones  (25°-29°)  correspond 
with  doubtful  qualities;  margarine  and  oleomargarine  give  much 
lower  figures,  13°- 17°.*  Genuine  butters  have  been  found  that 
give  values  materially  below  the  normal  deviation,  but  the  cause 
of  this  is  considered  by  Jean  to  be  that  the  cows  have  been  fed 
on  oilcake,  unaltered  oil  from  which  finds  its  way  into  the 
secreted  milk  in  quantity  large  enough  to  affect  the  refraction, 
though  too  small  to  produce  any  marked  effect  either  on  the 
saponification  equivalent,  or  the  Reichert-Meissl-Wollny  figure 
for  volatile  acids  (Chap,  vui.) 

Various  British  analysts  also  regard  the  oleorefractometer  as 
useful  in  preliminary  butter  examination,  but  other  chemists 
consider  its  value  in  this  respect  to  be  overrated ;  thus  de  Bruijn 
and  von  Leent  obtained  very  discordant  results  with  Dutch 
butters,  whilst  H.  O.  G.  Ellinger  found  f  that  genuine  Danish 
butters  gave  deflections  varying  between  23°  and  35°,  according 
to  the  season  of  the  year. 

Electrical  Conductivity. — In  general,  but  little  information 
is  obtainable  by  examining  the  relative  electrical  conductivities  of 
different  oils.  Olive  oil,  however,  has  a  much  lower  conducting 
power  than  most  other  oils  of  ordinary  occurrence,  and  hence, 
attempts  to  utilise  this  property  as  a  means  of  detecting  adultera- 
tion of  olive  oil  have  been  made,  notably  by  Palmieri,  who  has 
constructed  a  special  instrument,  or  diagometer,  for  the  purpose ; 
as  yet,  however,  this  method  does  not  seem  to  have  come  into 
practical  use  to  any  considerable  extent. 


SOLUBILITY  OF  OILS,  FATS,  &c.,  IN  VARIOUS 
SOLVENTS. 

The  immiscibility  of  "  oil  and  water  "  is  proverbial ;  but  some 
few  oils  are  known  where  the  solubility  in  water,  although  far 
from  perfect,  is  not  entirely  inconsiderable ;  thus  the  fusel  oils  of 
fermentation,  and  certain  oxidised  volatile  essential  oils,  and 
products  of  distillation  (e.g.,  phenol),  dissolve  in  water  to  the 

*  Journ.  Soc.  Ghent.  Industry,  1892,  p.  945;  from  Monit.  Sclent.,  1892,  6, 
p.  91. 

•\-The  Analyst,  1891,  p.  197;  from  Journ.   f.  prakt.   Chemie,,[2]  44,  p. 


54  OILS,    FATS,    WAXES,    ETC. 

extent  of  a  few  per  cents,  by  weight  at  ordinary  temperatures. 
As  a  general  rule,  however,  fixed  oils  and  hydrocarbons  are,  for 
practical  purposes,  entirely  insoluble  in  pure  water ;  in  some  few 
cases  dilute  alkaline  solutions  dissolve  them  somewhat  more  freely 
than  pure  water;  in  others  the  presence  of  acids  slightly  promotes 
solubility ;  but,  as  a  rule,  when  neutral  salts  are  present  to  any 
extent,  their  presence  prevents  the  solution  of  the  oil,  &c. ;  so 
that  on  agitating  an  aqueous  solution  with  solid  common  salt  or 
with  sodium  sulphate,  as  the  mineral  matter  goes  into  solution, 
the  dissolved  oil  is  more  or  less  thrown  out  of  solution.  The 
same  phenomenon  is  observed  with  the  potash  and  soda  salts  of 
most  of  the  fatty  acids,  so  that  when  an  aqueous  solution  of  such 
salts  (soaps)  are  treated  with  neutral  saline  matters,  the  organic 
salts  are  thrown  out  of  solution ;  this  property  is  largely  utilised 
in  the  ordinary  process  of  soap  boiling. 

Strong  alcohol  does  not  exert  any  great  degree  of  solvent  action 
in  the  cold  on  most  fixed  oils,  solid  fats,  or  waxes ;  whereas, 
many  essential  oils,  whether  hydrocarbons  or  of  oxidised  nature, 
are  extremely  freely  soluble  therein.  Similarly,  resins  and  free 
fatty  acids  are,  generally  speaking,  moderately  soluble  in  alcohol, 
especially  when  almost  anhydrous  and  warm.  Some  few  fixed 
oils,  too,  are  exceptional  as  regards  solubility  in  alcohol,  more 
especially  castor  oil  and  croton  oil,  and  to  a  lesser  extent  coker- 
nut  oil,  cow's  butter,  and  linseed  oil. 

Girard  finds  that  absolute  alcohol  at  15°  dissolves  the  following 
proportions  of  various  oils  : — 

RaPeoil'|  1-5  to  2-0  per  cent. 

Colza  oil,  J 

Mustard  seed  oil,     ....  2'7  ,, 

Hazelnut  oil,   .         .         .         .         .  3 '3  ,, 

Olive  oil, 3-6 

Almond  oil, 3 '9 

Sesame  oil,       .....  4*1  ,, 

Apricot  kernel  oil,   .         .         .         .  4 '3  ,, 

Nut  oil, 4-4 

Beechnut  oil,   .         .         .         .         .  4*4  ,, 

Poppy  seed  oil,         .         .         .         .  4  '7  ,, 

Hemp  seed  oil 5 '3  „ 

Cotton  seed  oil,  .         .         .  6*4  „ 

Aracliis  oil,      .....  6'6  „ 

Linseed  oil,      .         .         .         .         .  7'0  ,, 

Camelina  oil,   .....  7'H  „ 

Schadler  gives  the  following  Table  representing  the  quantities 
of  alcohol,  of  specific  gravity  '800,  required  to  dissolve  1  part  of 
oil  or  fat : — 


SOLUBILITY    IN    SOLVENTS. 


55 


Cold. 

Boiling. 

Parts. 

Parts. 

Almond  oil,        .        .            . 

60 

15 

Cacao  butter,     . 

4 

Cotton  seed  oil,                   .         . 

75 

... 

Croton  oil, 

36 

... 

Camelina  oil,     . 

68 

t 

Cod  liver  oil,     . 

45 

"G 

Hemp  oil, 

30 

Soluble  in  all  proportions. 

Japan  wax, 

3 

Linseed  oil,                          . 

40 

5 

Lard'  (hog's), 

27 

Madia  oil,          .                   . 

30 

6 

Nut  oil  (walnut), 

100 

60  alcohol  to  100  of  oil. 

Nutzneg  oil,                          . 

4 

Poppy  seed, 

25 

6 

Tallow  (sheep), 

45 

Suet  (ox  tallow), 

40 

Whale  oil  (bottlenose), 

... 

1 

As  a  general  rule,  fixed  oils  are  very  freely  soluble  in  carbon 
disulphide,  chloroform,  carbon  tetrachloride,  ether,  benzene,  light 
petroleum  distillate  (mostly  consisting  of  pentane  and  hexane 
with  their  homologues),  and  oil  of  turpentine;  and  on  this 
property  are  based  various  methods  of  extracting  oleaginous 
matters  from  natural  and  other  sources.  Castor  oil,  however, 
is  almost  insoluble  in  light  petroleum  spirit  •  whilst  drying 
oils,  when  oxidised  to  some  considerable  extent,  generally  be- 
come either  quite  insoluble  in  these  various  solvents,  or  nearly 
so,  the  decrease  in  solubility  usually  being  the  more  marked  the 
greater  the  degree  of  oxidation.  The  action  of  nitrous  acid  on 
an  oil  (conversion  into  elaidin,  Chap,  vn.)  usually  diminishes 
the  solubility  of  the  oil  thus  affected. 

Glacial  acetic  acid  has  been  found  by  Yalenta  to  be  a  con- 
venient solvent  for  certain  oils,  &c.,  as  a  means  of  separation 
from  one  another.  Thus,  when  equal  volumes  of  acid  and  oil  are 
intermixed,  the  oil  being  previously  warmed,  complete  solution, 
even  when  cold,  occurs  with  castor  oil,  rosin  oil,  and  olive  kernel 
oil,  whilst  rape  oil,  mustard  seed  oil,  and  wild  radish  seed  oil  are 
not  completely  dissolved  even  at  the  boiling  point  of  the  mixture. 
Most  other  oils  give  a  clear  fluid  whilst  hot,  which  on  cooling 
becomes  turbid,  owing  to  the  lesser  solubility  of  the  oil  in  the 
acetic  acid  at  lower  temperatures.  It  has  been  proposed  *  to 
make  use  of  the  temperature  at  which  turbidity  is  thus  brought 
about  as  a  distinguishing  test  for  oils  of  various  kinds ;  but  the 
figures  obtained  by  different  authorities  who  have  repeated 

1    *  Valenta,  Dinyler's  Poly  tech.  Journal,  252,  p.  296 ;  also,  Journal  of  the 
Chemical  Society, *W,  p.  1078. 


56. 


OILS,    FATS,    WAXES,    ETC. 


Yalenta's  experiments,  exhibit  so  much  discrepancy  as  to  render 
it  very  doubtful  whether  the  results  can  be  relied  upon  at  all,  as 
affording  indications  of  adulteration  or  otherwise.  Thus,  the 
following  values,  amongst  others,  have  been  obtained  by  A.  H. 
Allen  *  and  G.  H.  Hurst :—  f 


Oil. 

Valenta. 

Allen. 

Hurst. 

Olive  (green), 
„     (yellow),      . 

85 
111 

•c. 

|    28-76 

Almond,        .... 

110 

... 

Arachis,         .... 

112 

87 

72-92 

Apricot  kernel, 

114 

Neat's  foot,  .... 

... 

102 

G5-85 

Sesame,          .... 

107 

87 

... 

Melon  seed, 

108 

... 

... 

Cotton  seed, 

110 

90 

53-63 

Niger  seed,    .... 

49 

Linseed,         .... 

... 

57-74 

36-41 

Cod  liver,      .... 

101 

79 

65 

Menhaden,    .         ... 

... 

64 

Shark  liver, 

105 

95 

Porpoise,       .... 

... 

40 

98 

85 

Bottlenose,    .... 

... 

102 

74-84 

Whale,          .... 

38-86 

48-71 

Palm,    

23 

83 

Not  turbid  at  13 

Laurelberry, 

26-27 

40 

... 

Nutmeg  butter,     . 

27 

39 

Cokernut,      . 

40 

7'5 

M  turbid  at  13 

Palm  kernel, 

48 

32 

Bassia  fat  (Illipe), 

64'5 

... 

Cacao  butter, 

105 

... 

Beef  tallow, 

95 

Pressed  tallow  (M.P.,  55  '8), 

114 

... 

Tallow  oil  (cold  pressed), 

... 

47 

Hog's  lard,    .... 

... 

96-5 

... 

Lard  oil, 

... 

... 

69-76 

Butter  fat,     .... 

61  '5 

Oleomargarine, 

... 

.  96-5 

The  practical  value  of  the  test,  as  shown  by  the  above  numbers, 
is  obviously  not  very  great  ;  it  is  still  further  diminished  by  the 
circumstance  that  comparatively  slight  differences  in  the  strength 
of  the  glacial  acetic  acid  considerably  influence  the  temperature 
of  turbidity,  as  also  does  the  presence  or  otherwise  of  free  fatty 
acids ;  after  an  extended  examination,  Allen  concludes  that  the 
results  are  too  variable  and  indefinite  to  be  of  service  in 


*  Commercial  Organic  A  naly&is,  vol.  ii. ,  p.  2C. 
t  Journ.  Soc.  Ckem.  Industry,  1887,  p.  22. 


FUSING    AND    SOLIDIFYING    POINTS. 


57 


discriminating  the  quality  of  oils  ;  an  opinion  also  arrived  at  by 
G.  H.  Hurst,  by  Ell  wood,*  and  by  Thomson  and  Ballantyne,t 
the  latter  of  whom  obtained  the  following  numbers,  inter  alia, 
with  glacial  acids  of  different  strengths  : — 


1 

Percentage  of 
Free  Acid 

Temperature  of  Turbidity  with  Glacial 
Acetic  Acid  of 

Name  of  Oil. 

present 

(calculated  as 

Oleic  Acid). 

Sp.  gr.  1054-2 

Sp.  gr.  1055-2. 

Sp.gr.  1056-2. 

°C. 

•G. 

°C. 

Olive  (Syrian), 

23-88 

42 

... 

,,     (Gioja), 

9-42 

65 

80 

91 

Same  sample  freed  from  \ 
free  acid,  .         .         .  J 

None. 

87 

... 

... 

Arachis  oil  (commercial), 

6-20 

76 

96 

112 

,,       (French             ) 
refined),        { 

•62 

96 

m    i 

Not  completely 
dissolved. 

Eape  oil, 

4-54 
2-43 

105     \ 
110     / 

Hot  completely 
dissolved. 

,, 

Linseed  oil  (Baltic), 

3-74 

42 

59 

71 

(River  Plate), 

1-21 

56      - 

... 

,,        (East  India), 

•79 

57 

In  some  few  cases,  however,  the  comparatively  solubility  in 
glacial  acetic  acid  may  afford  a  useful  indication — e.g.,  in  de- 
tecting the  presence  of  rape  seed  oil  in  linseed  oil,  and  more 
especially  of  hydrocarbons  in  animal  and  vegetable  saponifiable 
oils  ;  thus,  mineral  oils  are  but  sparingly  soluble  in  glacial  acetic 
acid,  so  that  on  agitating  with  that  solvent  a  mixture  of  mineral 
oil  and  other  substances  freely  soluble  in  acetic  acid,  the  latter 
are  dissolved,  leaving  the  former  undissolved ;  in  this  way  the 
presence  of  rosin  oil  is  easily  detected  in  paraffin  and  petroleum 
distillates. 


FUSING  AND  SOLIDIFYING  POINTS. 

It  most  unfortunately  happens  that  several  different  thermo- 
metric  scales  are  in  use  in  different  countries ;  of  these  the 
Celsius  or  Centigrade  scale  is  by  far  the  most  convenient,  and 
is  accordingly  used  almost  exclusively  for  scientific  purposes. 
In  England,  however,  the  highly  inconvenient  Fahrenheit  scale 
is  still  largely  in  use  for  technical  and  general  purposes ;  whilst 
in  some  parts  of  the  Continent  the  Reaumur  scale  is  similarly 
employed.  The  following  formula  gives  the  means  of  translating 
the  temperature  expressed  on  any  one  of  these  systems  to  the 

*  Pharmaceutical  Journal,  3,  xvii.,  p.  519. 

t  Journ.  Soc.  Chem.  Industry,  1991,  x.,  p.  233. 


58  OILS,    FATS,    WAXES,    ETC. 

corresponding  value  expressed  on  either  of  the  others,  F  being 
the  value  on  the  Fahrenheit  scale,  C  that  on  the  Centigrade  scale, 
and  R  that  on  the  Reaumur  scale  :  — 

F_-_32  _  C  _  R 

9        ~  5  ~  4* 

This  formula  is  based  on  the  system  of  construction  of  the 
three  scales  respectively  ;  the  distance  between  the  "  ice  melting 
point  "  (sometimes  termed  the  "  freezing  point  ")  and  the  "  steam 
point"  (or  "boiling  point"  —  under  normal  atmospheric  pressure) 
being  divided  into  180  degrees  on  the  Fahrenheit  scale,*  100  on 
the  Centigrade,  and  80  on  the  Reaumur  scale  ;  so  that  the  rela- 
tive values  of  the  degree  in  each  scale  respectively  are  —  T-J-F  : 
TUIT  •  8"V  >  or  v  •  i  •  T'  The  Reaumur  and  Centigrade  scales, 
however,  begin  with  the  ice  melting  point  as  0,  so  that  the 
steam  point  is  at  80°  and  100°  on  the  two  scales  respectively  ; 
wrhilst  the  Fahrenheit  zero  is  32°  F.  below  the  ice  melting  point  ;  f 
whence  that  point  is  32°,  and  the  steam  point  32  +  180  =  212°, 
on  the  Fahrenheit  scale. 

From  the  above  formula  are  derived  the  following  equations, 
whereby,  when  requisite,  a  Centigrade  temperature  may  be  trans- 
lated into  the  corresponding  Fahrenheit  value,  and  so  on  :  — 


C  -      (F  -  32). 


F  =      C  +  32. 
o 


=      (F  -  32). 


*  This  particular  number  is  said  to  have  been  selected  on  account  of  some 
hazy  idea  on  the  part  of  the  inventor  that  the  temperature-range  between 
freezing  and  boiling  of  water  had  some  connection  with  the  number  of 
degrees  in  a  semicircle,  or  two  right  angles  ! 

-f  Presumably  because  M.  Fahrenheit  noticed  that  the  temperature  of  a 
mixture  of  snow  and  salt  was  32  of  his  degrees  below  the  freezing  point  of 
water,  and  concluded,  for  some  unknown  reason,  that  this  must  be  the 
initial  temperature,  or  absolute  zero. 


FUSING   AND    SOLIDIFYING    POINTS. 


The  following  table  affords  a  yet  simpler  means  of  effecting 
the  translation : — 


Centigrade. 

i 

Reaumur. 

Fahrenheit, 

• 
Centigrade. 

Rdaumur. 



Fahrenheit. 

| 
i  Centigrade. 

•jiunnrpjj 

j 

Fahrenheit. 

-  40 

-  32 

-  40 

+  7 

+  5-6 

+  44-6 

+  54 

+  43-2 

+  129-2 

-  39 

-  31-2 

-  38-2 

+  8 

+  6-4 

+  46-4 

+  55 

+  44 

+  131 

-  38 

-  30-4 

-  36-4 

+  9 

+  7-2 

+  48-2 

+  56 

+  44-8 

+  132-8 

-  37 

-  29-6 

-  34-6 

+  10 

t  8 

+  50 

+  57 

+  45-6 

+  134-6 

-  36 

-  28-8 

-  32-8 

+  11 

+  8-8 

+  51-8 

+  58 

+  46-4 

+  136-4 

-  35 

-  2S 

-  31 

+  12 

+  9-6 

+  53-6 

+  59 

+  47'2 

+  138-2 

-  34 

-  27-2 

-  29-2 

+  13 

+  10-4 

+  55-4 

+  60 

+  48 

+  140 

-  33 

-  26-4 

-  27-4 

+  14 

+  11-2 

+  57-2 

+  61 

+  48-8 

+  141-8 

-  32 

-  25-6 

-  25-6 

+  15 

i-  12 

+  59 

+  62 

+  49-6 

+  143-6 

-  31 

-  24-8 

-  23-8 

+  16 

+  12:8 

+  60-8 

+  63 

+  50-4 

+  145-4 

-  30 

-  24 

-  22 

+  17 

+  13  6 

+  62-6 

+  64 

+  51-2 

+  147-2 

-  29 

-  23-2 

-  20-2 

4-  18 

+  14-4 

+  64-4   +  65 

+  52 

+  149 

-  28 

-  22-4 

-  18-4 

+  19 

+  15-2 

+  66-2  !  +  66 

+  52-8 

+  150-8 

-  27 

-  21-6 

-  16-6 

+  20 

+  16 

+  68 

+  67 

+  53-6 

+  152-6 

-  26 

-  20-8 

-  14-8 

+  21 

+  16-8 

+  69-8 

+  68 

+  54-4 

+  154-4 

-  25 

-  20 

-  13 

+  22 

+  17-6 

+  71-6 

+  69 

+  55-2 

+  156-2 

-  24 

-  19-2 

-  11-2 

+  23 

+  18-4 

+  73-4 

+  70 

+  56 

+  158 

-  23 

-  18-4 

9-4 

+  24 

+  19-2 

+  75-2 

+  71 

+  56-8 

+  159-8 

-  22 

-  17-6 

-  7-6 

+  25 

+  20 

+  77 

+  72 

+  57-6 

+  161-6 

-  21 

-  16-8 

-  5-8 

+  26 

+  20-8 

+  78-8 

+  73 

+  58-4 

+  163-4 

-  20 

-  16 

4 

+  27 

+  21-6 

+  80-6 

+  74 

+  59-2 

+  165-2 

-  19 

-  15-2 

-  2-2 

+  28 

+  22-4 

+  82-4 

+  75 

+  60 

+  167 

-  18 

-  14-4 

0-4 

+  29 

+  23-2 

+  84-2 

+  76 

+  60-8 

+  168-8 

-  17 

-  13-6 

+  1-4 

-r  30 

+  24 

+  86 

+  77 

+  61-6 

+  170-6 

-  16 

-  12-8 

+  3-2 

+  31 

+  24-8 

+  87-8 

+  78 

+  62-4 

+  172-4 

-  15 

-  12 

+  5 

+  32 

+  25-6 

+  89-6 

+  79 

+  63-2 

+  174-2 

-  14 

-  11-2 

+  6-8 

+  33 

+  26-4 

+  91-4 

+  80 

+  64 

+  176 

-  13 

-  10-4 

+  8-6 

+  34 

+  27-2 

+  93-2 

+  81 

+  64-8 

+  177-8 

-  12 

9-6 

+  10-4 

+  35 

+  28 

+  95 

+  82 

+  65-6 

+  179-6 

-  11 

-  8-8 

+  12-2 

+  36 

+  2S'8 

+  96-8 

+  83 

+  66-4 

+  181-4 

-  10 

—  8 

+  14 

+  37 

+  29-6 

+  98-6 

+  84 

+  67-2 

+  183-2 

-  9 

-  7-2 

+  15-8 

+  38 

+  30-4 

+  100-4 

+  85 

+  68 

+  185 

-  8 

-  6-4 

+  17-6 

+  39 

+  31-2 

+  102-2 

+  86 

+  68-8 

+  186-8 

_   IT 

5-6 

+  19-4 

+  40 

+  32 

+  104 

+  87 

+  69-6 

+  188-6 

6 

-  4-8 

+  21-2 

+  41 

+  32-8 

+  105-8 

+  88 

+  70-4 

+  190-4 

5 

—  4 

+  23 

+  42 

+  33-6  +  107  -G 

+  89 

+  71-2 

+  192-2 

4 

-  3-2 

+  24-8 

+  43 

+  34-4  +  109-4 

+  90 

+  72 

+  194 

3 

-  2-4 

+  26-6 

+  44 

+  35-2  +111-2 

+  91 

+  72-8 

+  195-8 

_  2 

-  1-6 

+  28-4 

+  45 

+36  ;  +  113 

+  92 

+  73-6 

+  197-6 

—  1 

-  0-8 

+  30-2 

+  46 

+  36-8 

+  114-8 

+  93 

+  74-4 

+  199-4 

0 

0 

+  32 

i  +  47 

+  37-6 

+  116-6 

+  94 

+  75-2 

+  201-2 

+  1 

+  0-8 

+  33-8 

+  48 

+  38-4 

+  118-4 

+  95 

+  76 

+  203 

+  2 

+  1-6 

+  35-6 

+  49 

+  39-2 

+  120-2 

+  96 

+  76-8 

+  204-8 

+  3 

+  2-4 

+  37-4 

+  50 

+  40 

+  122 

+  97 

+  77-6 

+  206-6 

+  4 

+  3-2 

+  39-2 

+  51 

+  40-8 

+  123-8 

+  98 

+  78-4 

+  208-4 

+  5 

+  4 

+  41 

+  52 

+  41-6 

+  125-6 

+  99 

+  79-2 

+  210-2 

+  6 

+  4-8 

+  42-8 

+  53 

+  42-4 

+  127-4 

+  100 

+  80 

+  212 

! 

60  OILS,    FATS,    WAXES,    ETC. 

Iii  the  following  pages,  whenever  a  temperature  is  expressed 
as  a  number  without  the  scale  used  being  mentioned,  it  is  always 
to  be  understood  that  the  Centigrade  value  is  intended. 

Determination  of  Fusing  and  Solidifying  Points. — Inas- 
much as  most  natural  oils  and  fats,  itc.,  are  not  chemically  pure 
single  substances,  but  generally  consist  of  one  or  more  main 
ingredients  with  smaller  quantities  of  other  allied  bodies,  as  a 
general  rule  no  sharply  defined  temperature  exists  characteristic 
of  the  fusing  or  solidifying  point  of  any  given  variety,  although 
in  many  cases  pure  unadulterated  specimens,  even  though  of 
widely  various  origin,  do  not  differ  largely  in  these  respects. 
For  the  same  reason,  the  point  at  which  incipient  solidification 
on  chilling  first  becomes  manifest,  often  differs  considerably  from 
the  temperature  at  which  the  mass,  when  once  rendered  solid  by 
cold,  exhibits  incipient  fusion  on  gradual  heating.  Further,  a 
given  substance,  if  heated  considerably  above  its  melting  point 
and  then  cooled  quickly  so  as  to  solidify  it  again,  will  often  melt 
for  the  second  tyne  at  a  temperature  materially  different  from 
that  at  which  it  first  fused,  although  the  normal  melting  point  is 
more  or  less  regained  on  standing  for  some  time  ;  accordingly,  if 
the  fusing  point  of  a  solid  fat  that  has  been  once  melted  is  to  be 
determined,  a  sufficient  time  must  be  allowed  to  elapse  to  enable 
the  normal  physical  structure  to  be  re-assumed.  In  practice,  it 
is  generally  necessary  first  to  melt  the  substance  and  then  clarify 
it  by  subsidence,  or,  better,  by  filtration  through  dry  paper,  in 
order  to  remove  suspended  matters  and,  more  particularly,  water; 
so  that  the  purified  material,  after  cooling  and  solidification,  must 
be  allowed  to  stand  some  time  (at  least  an  hour  or  two,  but 
preferably  a  much  longer  period,  say  till  the  next  day)  before 
further  "examination. 

In  order  to  determine  the  fusing  point  of  a 
solidified  specimen,  several  different  methods  are 
in  use,  the  results  of  which  are  not  always  com- 
parable with  one  another;  so  that,  if  an  accurate 
comparison  of  two  substances  is  requisite,  it  is 
indispensable  that  both  must  be  examined  by  the 
same  process,  side  by  side.  One  of  the  most  fre- 
quently used  methods  consists  in  preparing  a 
capillary  tube  by  drawing  out  in  a  flame  a  short 
piece  of  quill  tubing  (Fig.  2);  the  fine  end  is 
sealed  up,  and  when  cool,  the  solid  to  be  ex- 
amined is  cut  into  very  fine  fragments  or  pul- 
verised, and  a  little  dropped  in  and  shaken  down 
into  the  capillary  tube.  This  is  then  bound  by 
Fig.  2.  wire,  string,  or  an  india-rubber  ring  to  the  stem 

of  a  thermometer  (Fig.  3),  so  that  the  centre  of 
the  bulb  is  about  level  with  the  substance  ;  the  whole  is  then 
placed  in  a  small  vessel  of  water  (or,  for  higher  temperatures, 


FUSING    AND    SOLIDIFYING    POINTS.  01 

melted  paraffin  wax)  which  is  very  slowly  raised  in  temperature, 
either  by  means  of  a  small  flame  underneath  (Fig.  4),  or,  pre- 
ferably, by  placing  it  inside  a  much  larger  similar  vessel ;  a  large 
flask  with  the  neck  cut  off  and  a  small  beaker  answer  well  (-Fig. 
5).  Olberg  employs  for  this  purpose  the  circulatory  arrange- 
ment shown  in  Fig.  6  ;  this  is  filled  with  water  or  oil,  the  heat 
being  applied  at  the  base  of  A. 

If  circumstances  permit,  two  such  capillary  tubes  (or  more) 
should    be   provided,   one   being  used   to  obtain  a   first   rough 


Fig.  3.  Fig.  4. 

approximation  to  the  melting  point,  and  the  others  used  sub- 
sequently to  obtain  a  nearer  result,  the  bath  being  previously 
slightly  cooled  below  the  first  approximate  value,  and  then  very 
slowly  heated  again,  so  that  several  minutes  are  requisite  to 
produce  a  rise  in  temperature  of  2°  or  3°  C.  The  thermometer 
and  attached  tube  are  used  as  a  stirrer  during  this  heating,  and 
the  temperature  noted  when  the  fragments  first  show  signs  of 
melting.  Frequently  this  temperature  (softening  point)  is 
measurably  below  that  requisite  to  cause  the  fragments  to  liquefy 
entirely,  and  run  down  to  the  bottom  of  the  capillary  tube  as  a 
clear  fluid  (temperature  of  complete  fusion). 


G2 


OILS,    FATS,    WAXES,    ETC. 


Instead  of  a  capillary  tube  sealed  up  at  the  end,  one  bent  into 
a  U  or  V  shape  may  be  employed,  the  solid  particles  being 
shaken  down  to  the  bend  or  angle.  Bensemann  *  modifies  the 
tube  by  drawing  it  out  as  represented  in  Fig.  7.  A  drop  or  two 


Fig.  5.  Fig.  0. 

of  melted  substance  is  introduced  into  the  bulbed  portion  of  the 
tube,  A,  and  fused  as  indicated  by  a.  After  standing  for  a 
sufficient  time,  the  tube  is  placed  in  water,  the  temperature  of 
which  is  very  slowly  raised  ;  the  temperature  of  incipient  lique- 
faction is  readily  observed  when  the  material  softens  and  begins 
to  run ;  at  a  little  higher  temperature  it  all  runs  down  as- 
indicated  by  b  ;  when  the  turbid  liquid  becomes  completely  clear, 
the  temperature  of  complete  fusion  is  attained. 

Another  method  of  operating  consists  in  drawing  out  the 
capillary  tube  as  before,  but  without  sealing  up  the  narrow  end  ; 
this  end  is  then  dipped  into  the  molten  substance  to  be 
examined  and  withdrawn,  so  that  half  an  inch  or  so  of  the 
capillary  tube  is  filled  up  with  the  material.  After  standing  at 
least  an  hour,  but  preferably  till  next  day,  the  capillary  tube  is 
attached  to  the  thermometer  and  placed  in  the  bath  as  before ; 
when  the  temperature  rises  to  the  softening  point  so  as  to  produce 
incipient  fusion,  the  plug  of  solid  matter  in  the  capillary  tube 
becomes  softened  where  it  touches  the  glass,  and  is  consequently 

*  Journ.  Soc.  Chem.  Industry,  1885,  iv.,  p.  5.35  ;  from  Rep.  Anal.  Chem., 
11,  p.  165. 


FUSING    AND    SOLIDIFYING    POINTS. 


63 


forced  upwards  by  the  hydrostatic  pressure  of  the  fluid  in  the 
bath  ;  when  this  occurs  the  temperature  is  noted.  The  former 
process,  as  a  rule,  is  to  be  preferred,  not  only  because  it  gives 
both  the  softening  point  and  the  temperature  of  complete  lique- 
faction, but  also,  because  by  withdrawing  the  source  of  heat  and 
allowing  the  completely  fluid  mass  to  cool  slowly,  the  temperature 
at  which  re-solidification  occurs  can  be  more  or  less  accurately 
determined.  With  some  kinds  of  mixed  substances,  the  sealed- 
up  capillary  tube  process  enables  three  different  temperatures  to 
be  ascertained,  viz.  : — First,  the  temperature  of  incipient  fusion 
when  the  most  fusible  constituent  commences  to  melt ;  second,  a 
temperature  when  this  constituent  has  become  so  far  melted  that 


the  solid  fragments  run  down  visibly;  and  third,  a  still  higher 
temperature  when  the  whole  mass  becomes'  clear  and  limpid, 
showing  that  the  whole  of  the  less  fusible  constituents  have  also 
become  completely  melted.  With  certain  mixtures  of  free  fatty 
acids,  &c.,  the  difference  between  the  lowest  and  highest  fusion 
temperatures  thus  determined  may  amount  to  upwards  of  5°  C. 

A  convenient  method  of  determining  the  softening  point  in 
certain  cases  consists  in  dipping  the  bulb  of  the  thermometer  into 
the  melted  material  to  be  examined,  and  causing  a  small  light 


OILS,    FATS,    WAXES,    ETC. 


glass  bulb  or  float  to  adhere  to  the  thermometer,  cemented 
thereto  by  the  substance  as  it  solidifies.  After  waiting  a  sufficient 
time  to  enable  the  mass  to  attain  its  normal  physical  structure, 
the  thermometer  and  bulb  are  placed  in  a  bath,  which  is 
gradually  heated ;  when  the  temperature  attains  the  softening 
point,  the  float  becomes  detached  and  rises  up  in  the  fluid. 
Instead  of  a  float,  a  thick  coating  of  the  substance  itself  may  be 
ap'plied  to  the  thermometer  by  dipping  the  latter  in  the  just- 
melted  substance  for  an  instant,  taking  out  again  until  the 
adherent  film  has  solidified,  and  repeating  the  operation  two  or 
three  times  so  as  finally  to  obtain  a  sufficiently  thick  coating. 
Fig.  8  represents  Pohl's  form  of  bath  for  the  purpose,  consisting 
of  a  wide  test-tube,  C,  through  the  cork  in  the  mouth  of  which 
passes  the  thermometer,  T,  the  heat  being  applied  by  means  of  a 
small  flame  impinging  on  a  flat  metal  disc,  supported  a  little 
distance  below  the  test-tube,  so  as  to  furnish  an  ascending 
current  of  warm  air.  Obviously  a  vessel  of  warm  water  may  be 
substituted  for  the  disc  and  flame.  A  modification  of  this  plan 
has  been  suggested  by  Messrs.  Cross  and  Be  van,*  where  a  thin 

piece  of  sheet  iron  (ferrotype 
plate)  is  cut  into  the  shape 
shown  in  Fig.  9,  about  ;f  inch 
long  and  f  or  J  inch  across ; 
at  A  the  plate  is  hammered  so 
as  to  form  a  minute  saucer  or 
depression,  and  at  B  a  hole  is 
cut  of  such  size  as  to  allow  the 
plate  to  fit  on  to  the  bulb  (coni- 
cal) of  a  thermometer.  The 
float  is  made  by  blowing  a  bulb 
on  the  end  of  a  thin  piece  of 
tubing,  and  fixing  a  bit  of  pla- 
tinum wire  therein,  bent  into 
an  L  shape.  A  drop  of  melted 
substance  is  put  in  the  saucer, 
and  the  end  of  the  wire  dipped 
therein,  the  stem  being  sup- 
ported in  a  vertical  position 
until  the  substance  solidifies, 
and  so  holds  it  firmly.  The 
thermometer  and  float  are 

placed  in  a  bath  of  water,  &c.  (preferably  mercury),  and  when 
the  temperature  rises  to  the  softening  point,  the  float  becomes 
detached  and  rises  to  the  surface. 

In  many   cases    the  temperatures  of  incipient  fusion  and  of 
complete  liquefaction  may  be  easily  determined  by  placing  small 
fragments  or  pinches  of  powder  of  the  substance  examined  on  the 
*  Journal  of  the  Chemical  Society,  vol.  xli.  (1882),  p.  111. 


Fi.  9. 


FUSING    AND    SOLIDIFYING    POINTS. 


65 


surface  of  a  bowl  of  perfectly  clean  mercury,  the  temperature  of 
which  is  gradually  raised,  a  thermometer  being  placed  therein. 
When  complete  fusion  is  effected,  the  substance  becomes  a  minute 
drop  of  clear  fluid,  which  usually  spreads  out  film-wise  over  the 
surface  of  the  mercury.  A  n  ingenious  modification  of  this  method 
has  been  proposed  by  J.  Loewe,*  where  the  substance  is  first  applied 
to  the  end  of  a  platinum  wire  (by  dipping  into  the  just-fused 
substance),  so  as  to  cover  it  completely ;  the  coated  wire  is  then 
supported  by  means  of  an  insulating  holder  of  glass,  just  below 
the  surface  of  the  mercury,  and  connected  with  one  pole  of  a 
small  galvanic  cell,  whilst  the  mercury  is  connected  with  the 
other  pole.  As  long  as  the  substance  is  unmelted  no  contact 
takes  place  between  the  platinum  wire  and  mercury ;  but  as  soon 
as  fusion  takes  place  contact  is  brought  about,  and  an  electric 
bell  included  in  the  circuit  is  made  to  ring.  Fig.  10  represents 


Fig.  10. 

the  general  arrangement  employed,  the  mercury  being  placed  in 
a  capsule  heated  over  a  small  water  bath,  and  the  temperature 
ascertained  by  means  of  a  thermometer  plunged  therein.  Instead 
of  a  platinum  wire  coated  with  the  substance  examined,  Christo- 
manosf  employs  a  drawn-out  capillary  tube  into  which  the  melted 
substance  is  sucked  or  poured,  a  platinum  wire  being  imbedded 
in  the  material.  After  solidifying  and  standing  sufficiently  long 
to  attain  the  normal  texture  of  the  substance  examined,  the 
capillary  tube  is  heated  in  a  mercury  bath,  electrical  connections 
being  applied  to  the  bath  and  platinum  wire,  so  that  when  the 
substance  fuses  contact  is  made  and  a  bell  rung.  A.  similar 
arrangement  is  in.  use  in  the  Paris  Municipal  Laboratory,  the 
substance  tested  being  placed  in  the  bend  of  a  U-shaped  tube 
with  a  platinum  wire  in  each  limb,  together  with  some  mercury, 
which  runs  down  and  makes  contact  when  fusion  occurs. 

*  Dingier 's  Polytechnisches  Journal,  201,  p.  250. 

t  Journal  Soc.  Chem.  Industry,   1890,   p.    894 ;    from  Berichte  d.  Deut. 
Chem.  Gcs.,  1890.  p.  1093. 

5 


66  OILS,    FATS,    WAXES,    ETC. 

If  the  fusing  point  of  a  fluid  oil  that  has  been  solidified  by 
chilling  is  to  be  determined,  the  bath  used  must  be  itself  cooled 
down  below  the  fusing  point,  and  gradually  allowed  to  rise  in 
temperature.  Strong  brine,  giycerol  diluted  Avith  a  little  water, 
or  calcium  chloride  solution  may  be  conveniently  used  for  tem- 
peratures below  0°.  When  the  solidification  point  of  a  fluid  oil 
or  melted  fat  is  to  be  determined,  a  rough  approximation  may 
often  be  obtained  by  placing  some  in  a  small  narrow  test-tube, 
or  dipping  into  the  fluid  a  loop  of  platinum  wire  so  as  to  cause  a 
small  drop  to  adhere,  and  immersing  in  a  bath  of  water,  brine, 
&c.,  which  is  being  cooled  down  by  an  external  application  of 
broken  ice  or  snow  and  salt,  &c.,  noting  the  temperatures  when 
transparency  first  ceases,  and  when  visible  solidification  of  the 
whole  mass  has  ensued.  In  most  cases,  however,  the  temperatures 
thus  ascertained  are  too  low,  because  superfusion  is  extremely 
apt  to  occur  with  oils  and  fats.  If,  however,  a  moderately  large 
quantity  of  substance  be  used  (15  to  20  grammes  at  least), 
it  frequently  occurs  that  as  soon  as  solidification  begins  a  more 
or  less  considerable  rise  in  temperature  of  the  mass  takes  place, 
just  as  when  water  cooled  down  below  0°  in  a  dustless  still 
atmosphere  rises  to  0°  whenever  freezing  actually  commences  ;  or 
just  as  the  temperature  of  a  supersaturated  solution  of  Glauber's 
salt  (sodium  sulphate)  rises  when  the  fluid  sets  to  a  crystalline 
mass.  The  higher  temperature  thus  indicated  is  permanent  for 
a  time  as  solidification  goes  on,  and  is  usually  much  more  nearly 
exact  than  the  lower  one  attained  before  solidification  com- 
menced ;  but  even  this  higher  one  is  often  several  degrees  below 
the  temperature  of  incipient  fusion  (and  a  fortiori  below  that  of 
complete  fusion)  indicated  when  the  mass  has  been  solidified 
completely,  allowed  to  stand  some  time,  and  then  re-melted  in 
a  sealed-up  capillary  tube. 

Differences  of  this  description  are  more  usually  observed  when 
the  substances  in  question  are  mixtures  of  different  constituents 
melting  at  different  temperatures ;  on  the  other  hand,  a  single 
substance  in  a  state  of  moderate  purity  (e.g.,  a  well  purified 
sample  of  a  given  fatty  acid,  such  as  stearic  acid)  usually  shows 
but  little  difference  between  the  temperatures  of  incipient  fusion 
and  of  complete  fusion  in  a  closed  capillary  tube,  and  those 
where  the  limpid  fused  mass  first  shows  signs  of  turbidity,  and 
where  visible  complete  solidification  occurs,  on  slightly  cooling 
the  melted  substance. 

With  some  kinds  of  oils,  time  is  an  important  factor  in  the 
determination  of  the  temperature  at  which  solidification  takes 
place  on  chilling,  inasmuch  as  frequently  no  solidification  at  all 
is  visible  on  cooling  for  a  short  time  to  a  given  temperature 
(e.g.,  —  15°  C.),  whereas  more  or  less  complete  solidification  takes 
place  on  keeping  for  several  hours  at  a  temperature  not  so  low 
by  several  degrees  (e.g.,  —  5°).  In  most  cases,  if  a  fragment  of 


FUSING    AND    SOLIDIFYING    POINTS. 


67 


oil,  previously  solidified  by  chilling,  be  dropped  into  a  specimen 
of  cooled  oil,  solidification  is  brought  about  much  sooner,  the 
particle  introduced  acting  as  a  "nucleus  "  and  facilitating  crystal- 
lisation in  the  well-known  way  observed  with  other  bodies  (e.g., 
supersaturated  solution  of  sodium  sulphate  •  superfused  metals  ; 
glycerol ;  monohydrated  sulphuric  acid ;  water  chilled  down 
whilst  at  rest  below  0°,  &<?.).  For  determinations  of  this  kind, 
baths  of  fairly  constant  low  temperatures,  capable  of  being  main- 
tained for  considerable  periods,  are  requisite ;  Hoffmeister  uses 
for  this  purpose  various  saline  solutions  cooled  externally  by  a 
freezing  mixture ;  by  suitably  choosing  the  saline  substance  and 
the  strength  of  its  solution,  baths  of  constant  temperature  are 
obtainable  so  long  as  any  liquid  remains  unsolidified  or  any  solid 
unmelted.  Thus  the  following  temperatures  correspond  with 
solutions  of  the  respective  strengths  : — 


Temperature. 

Solution. 

Degrees  C. 
0 
-    2-85  to  -    3-0 

-     5-0 

-    8  '7    to  -    <)•() 
-  15-4    to  -  15-0 

Distilled  Water. 
Potassium  nitrate,    . 
\  Potassium  nitrate,    . 
I  Sodium  chloride. 
Barium  chloride, 
Ammonium  chloride, 

13  parts  per 
13 
3-3 
35-8 
25 

100  of  water. 

55 
3  5 

55 

Chilling  baths  of  this  description  are  more  especially  of  use  in 
the  examination  of  lubricating  oils  with  respect  to  their  congeal- 
ing temperatures. 

The  following  table,  mostly  derived  from  Schadler's  Technologic 
der  Fette  und  Oele,  exhibits  the  average  melting  and  solidifying 
points  of  many  of  the  more  commonly  occurring  fats  and  oils  : — 

FREEZING  AND  MELTING  POINTS  OF  OILS,  &c. 


Name. 


Arachis  oil, 

Almond  oil, 

Bassia  fat  (Galam  butter), 

Beechnut  oil, 

Ben  oil, 

Belladonna  seed  oil,     . 

Butter, 

Bone  grease, 

Cacao  butter, 

Castor  oil, 

Cokernut  oil, 

Colza  oil,     . 

Cotton  seed  oil,  . 

Cress  seed  oil, 


Melting  Point 
after 
Solidification. 

Solidifying  Point 
•when  Cooled 
(after  Fusion,  if 
Solid). 

Degrees. 

Degrees. 

, 

-    3  to  -  4 

-  20 

28  to  29 

21  to  22 

... 

-16-5  to  -17-5 

m 

About  0 

... 

-  16 

29  to  35 

20  to  30 

44  to  45 

35 

33  to  34 

20-5 

... 

-  18 

24*5 

20  to  20-5 

-    6 

-    2 

... 

-  15 

68 


OILS,    FATS,    WAXES,    ETC. 


FREEZING  AND  MELTING  POINTS  OF  OILS,  &c.  —  Continued. 


Name. 

Melting  Poiut 
Hfter 
Solidification. 

Solidif 
whe 
(after 
5 

Degrees. 

D( 

Goa  butter  (Brindonia  indica),     . 
Goose  grease,       ..... 

40 
26 

Gourd  seed  oil,    ..... 
Hazelnut  oil, 
Hemp  seed  oil,    ..... 
Japanese  wax,     ..... 
Laurel  berry  fat,          .... 
Linseed  oil,          ..... 
Madia  oil,            ..... 
Nut  oil,       

53  to  54 
38 

43'5  to  44 

-  17 

-  27 
40 

Oleic  acid,  ...... 
Olive  oil                        .... 

2 

-  16 

Palm  oil,     ...... 
Pine  oil,       ...... 
Rape  seed  oil  (Brassica  napus  oleifera), 
Radish  seed  oil,  

30  to  41 

21 

Spindel  oil  (Euonymus  europseus), 
Sunflower  seed  oil,      .... 
Tallow,        
Tobacco  oil, 
Train  oil,     ...... 
Virola  fat  (Virola  sebifera), 
Wax,  
Whale  oil                                ... 

46  to  50 

45 
62  to  64 

36 

01 

Al 

0  t 

Weld  oil. 

• 

Beloi 

Solid). 


Degrees. 

-  16 
32 
18 

-  16 

-  15 

-  18 

27  to  -  28 
40  to  41 
30 

-  19 

-  15 

-  28 
33 

-  6 

2  to  4 
16  to  -  18 
21  to  37 

-  18 

-  3 

-  4 

-  5 

-  10 

-  16 
36  to  40 

-  25 

to  -  2 

40 

About  60 
0  to  -  2 


WlMMEL. 


Melts  at 

Becomes 
Turbid   at 

Temperature 
rises  during 
Solidification  to 

Sheep's  tallow  (fresh),  . 
(old),     .         . 
Ox  tallow  (fresh), 
(old),     . 
Hog's  lard,    .... 
Butter  (fresh), 

Degrees. 

47 
50-5 
43 
42-5 
41  -5  to  42 
31  to  31  -5 

Degrees. 
36 
39-5 
33 
34 
30 
19  to  20 

Degrees. 
40  to  41 
44  to  45 
36  to  37 
38 
32 
19  -5  to  20  -5 

Cacao  butter, 
Coker  butter, 
Palm  butter  (fresh),      . 
(old), 
Nutmeg  butter,     . 

34  to  35-5 
24-5 
30  to  36 
42 
43  -5  to  44 
62  to  62-5 

20-5 
20  to  20-5 
21  to  24 
38 
33 

27  to  29  5 
22  to  23 
21  -5  to  35 
39-5 
41  -5  to  42 

Spermaceti,  .... 

44  to  44  5 

... 

FUSING   AND    SOLIDIFYING    POINTS. 
RiJDORFF. 


Melts  at 

Solidifies  at 

Degress. 

Degrees. 

Yellow  wax, 

63-4 

6  1  -5  to  62  -6 

\Vhite  wax, 

61-8 

61-6 

Spermaceti, 

43  -5  to  44  -3 

43-4  to  44-2 

Japanese  wax, 

50-4  to  51 

... 

Cacao  butter, 

33-5 

... 

Nutmeg  butter, 

70  to  SO 

... 

Sheep's  tallow, 

4G-5  to  47  '4 

32  to  36 

Ox  tallow,    . 

43-5  to  45-0 

27  to  35 

The  foregoing  fusing  and  solidifying  points  of  various  solid 
fats  are  given  by  Wimmel  and  Eiidorff  respectively. 

The  fusion  point  of  a  pure  glyceride,  or  mixture  of  glycerides, 
is  often  materially  altered  if,  as  is  often  the  case,  any  considerable 
amount  of  hydrolysis  has  taken  place,  either  through  develop- 
ment of  "  rancidity"  through  fermentative  changes  taking  place 
on  account  of  the  presence  of  mucilaginous  or  albuminous 
matters,  or  by  the  agency  of  acids  during  refining,  or  otherwise. 
Hence,  the  numbers  obtained  with  various  samples  of  otherwise 
pure  oils  (i.e.,  unadulterated  with  cheaper  ones)  are  apt  to  vary. 
More  nearly  concordant  figures  are  obtained  if  the  whole  of 
the  glyceride  is  saponified  by  means  of  alkalies  (e.g.,  alcoholic 
potash),  and  the  fatty  acids  separated  from  the  resulting  soap 
by  evaporating  off  alcohol,  dissolving  the  residue  in  hot  water, 
acidulating  with  a  mineral  acid  in  excess,  thoroughly  agitating 
till  all  the  soap  is  decomposed,  and  finally  allowing  to  cool,  and 
removing  the  cake  of  solidified  fatty  acids  that  separates  and 
forms  on  standing. 

By  determining  the  fusing  point  of  the  fatty  acid  cake  thus 
produced  side  by  side  with  that  similarly  prepared  from  a  sample 
of  oil  of  known  purity,  or  from  a  mixture  of  known  character, 
useful  indications  as  to  purity  or  otherwise  are  often  attainable  ; 
for  example,  the  fatty  acids  from  genuine  olive  oil  usually  fuse 
at  from  22°  to  26°  C.,  and  those  from  refined  cotton  seed  oil  at 
35°  to  40°,  so  that  any  considerable  admixture  of  cotton  seed  oil 
with  olive  oil  will  usually  result  in  yielding  a  cake  of  notably 
raised  fusing  point.  The  amount  of  rise,  however,  does  not  give 
any  very  clear  indication  of  the  amount  of  admixture,  because,  as 
a  general  rule,  mixtures  of  different  substances  fuse  at  a  tempera- 
ture lower  than  that  calculable  arithmetically  from  the  relative 
amounts  and  fusing  points  of  the  ingredients  (vide  p.  73). 

The  following  table  represents  the  melting  and  solidifying 
points  of  the  mixed  fatty  acids  obtained  from  various  oils  and 
fats,  as  given  by  Schadler  : — • 


70 


OILS,    FATS,    WAXES,    ETC. 


Name  of  Oil.  &c. 

Melting  Point. 

Solidifying  Point. 

Degrees  C. 

Degrees  C. 

Apricot  kernel, 

4-5 

0 

Almond, 

14 

5 

Arachis, 

32  to  33 

29  to  30 

Butter, 

37 

33 

Cacao  butter, 

49-5 

46  '5  to  47 

Castor, 

13 

3 

Charlock,       . 

18  to  19 

13 

Chinese  tallow, 

57 

52 

Cotton  seed, 

37  to  38 

32-5 

Cokernut, 

24  to  25 

20  to  20-5 

Colza,    .... 

20  to  21 

14  to  14-5 

Galam  butter, 

35-5 

30 

Hemp,  .... 

19 

15 

Lard,     .... 

38  to  39 

35 

Linseed, 

17 

13-5 

Lallemantia  (Gundschit), 

11  to  12 

Malabar  tallow, 

56-5 

54-8 

Margarine,     . 

42 

39-4 

Nutmeg, 

42-5 

40 

Nut  (Walnut), 

20 

16 

.    Olive,     .... 

26  "5  to  28 

21  -5  to  22 

Poppy, 

20-5 

16-5 

Palm,     .... 

45  to  46 

42  to  43 

Rape,     .... 

21 

16 

Suet  (Ox),      . 

45-5 

43 

Sesame, 

35  to  36 

31-5  to  32 

Spermaceti,   . 

13-5 

Sunflower, 

23 

17 

Tacamahac,   . 

36-5 

31 

Tallow  (Sheep),      . 

49 

46 

Unguadia, 

19 

10 

Wool  grease, 

41-8 

40 

Slightly  different  values  have  been  given  by  other  observers, 
the  variations  arising  partly  from  differences  between  the  par- 
ticular specimens  examined  and  partly  from  differences  in  the 
mode  of  observation.  Thus  the  figures  below  given  by  Hiibl 
are  respectively  the  temperatures  of  complete  liquefaction  (as 
noticed  by  melting  in  a  narrow  test-tube,  stirring  with  a  ther- 
mometer, and  noting  the  temperature  when  turbidity  disap- 
peared), and  of  incipient  solidification  (as  noticed  by  cooling 
down  after  complete  melting,  and  noticing  when  cloudiness  com- 
menced) ;  whilst  those  of  Beiisemann  are  (A)  the  temperature  of 
complete  liquefaction,  when  all  turbidity  disappears,  as  deter- 
mined in  the  above  described  form  of  capillary  tube,  and  (B) 
the  somewhat  lower  temperature  when  the  substance  was  suffi- 
ciently liquefied  to  run  down  in  the  capillary  tube,  but  was  not 
thoroughly  fused  to  a  limpid  fluid  : — 


FUSING   AND    SOLIDIFYING    POINTS. 


71 


Fusing  Point. 

Solidifying  Point. 

Hiibl. 

Bensemann. 

Allen. 

HUbl. 

Bach. 

Allen. 

A                  B. 

Dees. 

C. 

Degs. 

Degs. 

Degs. 

Degs. 

Degs. 

Degs. 

Olive  oil,  .     .     . 

26-0 

26  to  27 

23  to  24 

26  -Q 

21-2 

22-0 

21-0 

Almond  oil,  .     .   i  14*0* 

... 

... 

5-0 

Arachis  oil,   .     .     27*7 

34  to  35 

31  to  32 

29-5 

23  -8 

31-0 

28-0 

Rape  oil,  .     .     . 

20-1 

21  to  22 

18  to  19 

19-5 

12-2 

15-0 

18-5 

Cotton  seed  oil,. 

377 

42  to  43 

39  to  40 

35-0 

30-5 

35-0 

32-0 

Sesame  oil,    .     .   !  26  '0 

29  to  30 

25  to  26 

23-0 

22-3 

32-5 

18-5 

Linseed  oil,  .     .     17;0 

... 

24-0 

13-3 

... 

17-5 

Poppy  oil,      .     . 

20-5 

..  . 

16-5 

Hemp  seed  oil.  . 

19-0 

... 

15-0 

... 

Walnut  oil,    .  '  . 

20-0 

... 

16-5 

... 

... 

Castor  oil, 

13-0 

3-0 

2-0 

... 

Palm  oil,  ... 

47-8 

50  :0 

42-7 

... 

45-5 

Cokernut  oil, 

24-6 

24-0 

204 

... 

20-5 

Japan  wax,   .     . 

... 

56-0 

... 

53-0 

Myrtle  wax,  .     . 

... 

47-5 

... 

46-0 

Lard,    .... 

... 

... 

44-0 

... 

42 

39-0 

Tallow,     .     .     . 

45-0 

... 

... 

43  to  50 

44  to  49 

... 

Shea  butter,  .     . 

395 

... 

38-0 

... 

... 

The  following  tables  by  Heintz  *  represent  the  melting  points 
of  various  definite  mixtures  of  fatty  acids  : — • 


MIXTURES  OF  MYRISTIC  AND  LAURIC  ACIDS. 


Percentage  of 

Melting  Point. 

Solidification  Point. 

Myristic  Acid. 

Laurie  Acid. 

Degrees  C. 

Degrees  C. 

58-8 

100 

0 

51-8 

47-3 

90 

10 

49-6 

44-5 

80 

20 

46-7 

39-0 

70 

30 

43-0 

39-0 

60 

40 

37-4 

35-7 

50 

50 

36-7 

33-5 

40 

60 

35-1 

32-3 

30 

70 

38-5 

33-0 

20 

80 

41-3 

36-0 

10 

90 

43-6 

... 

0 

100 

*  Poggendorff  Annalen,  92,  p.  588. 


72 


OILS,    FATS,    WAXES,    ETC. 
MIXTURES  OF  PALMITIC  AND  MYRISTIC  ACIDS. 


Melting  Point. 

Solidification  Point. 

Percentage  of 

Palmitic  Acid. 

Myristic  Acid. 

Degrees  C. 

Degrees  C. 

62-0 

... 

100 

0 

61-1 

58-0 

95 

5 

60-1 

55-7 

90 

10 

58-0 

53-5 

80 

20 

54-9 

51-3 

70 

30 

51-5 

49-5 

60 

40 

47-8 

45-3 

50 

50 

47-0 

43-7 

40 

60 

46-5 

43-7 

35 

65 

46-2 

44-0 

32-5 

67-5 

46-2 

43-7 

30 

70 

49-5 

41-3 

20 

SO 

51-8 

45-3 

10 

90 

53'8 

0 

100 

MIXTURES  OF  STEARIC  AND  PALMITIC  ACIDS. 


Percentage  of 

Melting  Point. 

Solidification  Point. 

Stearic  Acid. 

Palmitic  Acid. 

Degrees  C. 

Degrees  C. 

69-2 

100 

0 

67-2 

62-5 

90 

10 

65-3 

60-3 

80 

20 

62-9 

59-3 

70 

30 

60-3 

56-5 

60 

40 

56-6 

55-0 

50 

50 

56-3 

54-5 

40 

60 

55-6 

54-3 

35 

65 

55-2 

54-0 

32-5 

67'5 

55-1 

54-0 

30 

70 

57-5 

53-8 

20 

80 

60-1 

54-5 

10 

90 

62-0 

... 

0 

100 

FUSING  AND  SOLIDIFYING  POINTS. 
MIXTURES  OF  STEARIC  AND  MYRISTIC  ACIDS. 


73 


Percentage  of 

Melting  Point. 

Stearic  Acid. 

Myristic  Acid. 

69-2 

100 

0 

67-1 

90 

10 

65-0 

80 

20 

62\S 

70 

30 

59-8 

60 

40 

54-5 

50 

50 

50-4 

40 

60 

48-2 

30 

70 

47-8 

20 

80 

51-7 

10 

90 

53-8 

0 

100 

1 

MIXTURES  OF  STEARIC  AND  LAURIC  ACIDS. 


Melting  Point 

Perc 

Stearic  Acid. 

69-2 

100 

67-0 

90 

64-7 

80 

62-0 

70 

59-0 

60 

55-8 

50 

50-8 

40 

43-4 

30 

38-5 

20 

41-5 

10 

43-6 

0 

Myristic  Acid. 


0 
10 
20 
30 
40 
50 
60 
70 
SO 
90 
100 


These  tables  amply  illustrate  the  peculiarity  above  referred  to 
in  cases  where  mixtures  are  heated — viz.,  that  the  melting  point 
of  the  mixture  is  almost  invariably  lower  than  that  calculated 
from  the  relative  proportions  and  fusing  points  of  the  ingredients, 
and  in  certain  cases  falls  below  the  melting  point  of  the  most 


OILS,    FATS,    WAXES,    ETC. 

MIXTURES  OF  PALMITIC  AND  LAURIC  ACIDS. 


Percentage  of 

Melting  Point. 

Palmitic  Acid. 

Laurie  Acid. 

| 

62-0 

100 

0 

59  -8 

90 

10 

57-4 

80 

20 

54-5 

70 

30 

51-2 

60 

40 

47-0 

50 

50 

40-1 

40 

60 

38-3 

30 

70 

37-1 

20 

80 

41-5 

10 

90 

"?* 

0 

100 

fusible  of  the  ingredients.  Thus,  in  the  case  of  a  mixture  of 
myristic  and  lauric  acids  containing  equal  quantities  (50  per 
cent.)  of  each,  since  the  ingredients  melt  respectively  at  58°-8 
a-nd  43° -6  C.,  the  melting  point  of  the  mixture  would  a  priori  be 

..       .     58*8  +  43*6        „,„  „        ,  ..  n     •    o»-o  t 

expected  to  be-     — T) —        =  51  •'!;  whereas  it  actually  is  61  *4, 

or  13° -8  lower  than  the  calculated  temperature,  and  6°*2  lower 
than  the  fusing  point  of  the  most  fusible  ingredient. 

Dalican's  Method. — The  following  table  by  Dalican*  repre- 
sents the  solidifying  points  of  various  mixtures  of  pure  free 
stearic  and  oleic  acids,  analogous  to  those  obtained  by  saponify- 
ing tallow  completely  and  separating  the  fatty  acids  from  the 
soaps  formed ;  these  were  deduced  by  determining  the  tempera- 
ture to  which  the  thermometer  rose  when  some  20  grammes  of 
mixed  pure  fatty  acids  were  placed  in  a  test-tube  at  a  tempera- 
ture a  little  above  the  solidifying  point,  and  allowed  to  cool 
slowly  ;  when  incipient  solidification  became  visible  the  contents 
of  the  tube  were  stirred  with  the  thermometer  immersed  therein, 
giving  a  rotary  movement  three  times  from  right  to  left,  and 
three  times  in  the  opposite  direction ;  during  this  stirring  the 
thermometer  usually  slightly  fell  just  at  first,  but  in  every  case 
rose  again  to  a  point  where  the  temperature  remained  stationary 
for  about  two  minutes,  the  disengagement  of  latent  heat  during 
solidification  balancing  the  loss  of  heat  by  radiation  and  convec- 
tion, &c.  The  temperatures  quoted  are  the  stationary  ones  thus 
observed  with  the  various  mixtures  examined.  The  joint  per- 
centages given  in  the  table  only  add  up  to  95,  the  average  yield 
of  total  fatty  acids  from  tallow  being  taken  as  95  per  cent.,  after 

*  Moniteur  Scientifique,  Paris,  1868. 


FUSING    AND    SOLIDIFYING    POINTS. 


allowing  for  small  quantities  of  water  present  and  loss  of  weight 
by  elimination  of  glycerol  (vide  Chap,  vin.)  : — 


Tf-mporature 
Centigrade. 

Stearic  Acid. 

Oleic  Acid. 

Temperature 
Centigrade. 

Stearic  Acid. 

Oleic  Acid. 

40 

35-15 

59-85 

45-5 

52-25 

4275 

40%") 

36-10 

58-90 

46 

53-20 

41-80 

41 

38-00 

57-00 

46-5 

55-10 

39-90 

41-5 

38-95 

56-05 

47 

57-95 

37-05 

42 

40-90 

54-10 

47-5 

58-90 

36-10 

42-5 

4275 

52-25 

48 

61-75 

33-25 

43 

43-70 

51-30 

48-5 

66-50 

28-50 

43-5 

44-65 

50-35 

49 

71-25 

23-75 

44 

47-50 

47-50 

49-5 

72-20 

22-80 

44-5 

49-40 

45-60 

50 

75-05 

19-95 

43 

51-30 

43-70 

The  method  of  manipulation  thus  employed  by  Dalican  is 
applicable  in  the  case  of  most  other  substances  the  solidifying 
point  of  which  is  required ;  but  the  amount  of  rise  indicated  by 
the  thermometer  above  the  temperature  of  incipient  solidification 
varies  considerably  in  different  cases,  a  constant  temperature  for 
two  minutes  or  more  not  being  always  attained.  Finkener*  finds 
that  more  concordant  valuations  are  obtainable  if  the  vessel 
containing  the  fused  fatty  matter  is  enclosed  in  an  envelope  of 
wadding,  or  jacketted  with  a  wooden  envelope,  so  as  to  diminish 
the  rate  of  cooling. 


Solidifying  Point 
of  Tallow  Fatty 

Percentage  of  "  Stearine  "  (Solid  Fatty  Acids)  of  Solidification  Point 

Acids. 

' 

Degrees  C. 

48  Degrees  C. 

50  Degrees  C. 

52  Degrees  C. 

54  S  Degrees  C. 

10 

3-2 

2-7 

2-3 

2-1 

15 

7-5 

6-6 

5-7 

4-8 

20 

13-0 

11-4 

9-7 

8-2 

25 

19-2 

17-0 

148 

12-6 

30 

27-9 

23-2 

21-4 

18-3 

35 

39-5 

34-5 

30-2 

25-8 

40 

57'8 

49-6 

43-5 

37-0 

42                        66-6 

57-6 

50-5 

429 

44                        77-0 

66-2 

58-4 

49-8 

46                        87-5 

75-8 

67-0 

56-8 

48                      100-0 

87-2 

76-6 

65-0 

50 

100-0 

87-0 

74-5 

52 

100-0 

84-8 

54 

... 

95-3 

54-8 

100-0 

*  Journal  Soc.  Chem.  Industry,  18S9,  p.  423,  and  1890,  p.  1071. 


OILS,    FATS,    WAXES,    ETC. 


De  Schepper  and  Geitel  give  the  foregoing  table  representing 
the  amounts  of  mixed  solid  fatty  acids  of  different  solidification 
points  practically  obtainable  from  tallow,  when  these  acids  are 
separated  from  oleic  acid  to  such  an  extent  as  to  possess  the 
solidification  points  named. 

The  same  authors  give  the  following  analogous  table  for  the 
relative  amounts  of  mixed  solid  fatty  acids  practically  obtainable 
from  palm  oil : — 


Solidifying  Point 

of  Palm  Oil  Fatty 

Percentage  of  " 

Stearine  "  (Solid  Fatty  Acid?)  of  Solidification  Point 

Acids. 

Degrees  C. 

48  Degrees  C. 

50  Degrees  C. 

52  Degrees  C. 

55-4  Degrees  C. 

10 

4-2 

3-6 

3-2 

2-6 

15 

10-2 

9-8 

7-8 

6-6 

20 

17-4 

150 

14-4 

11-0 

'25 

26-2 

22-4 

19-3                    16-2 

30 

34-0 

30-5 

26-6                   22-3 

35 

45-6 

40-8                    35-8                    29-8 

40 

63-0 

55-2                    48-6                   40-6 

42                        70-5 

02-2                   552                   45-5 

44                        79-2 

70-2 

62-0                   51-4 

46 

89-4 

78-8 

69-8 

57-8 

48 

100-0 

88-0                   78-6                   65-0 

50 

100-0                    89-6 

73-4 

52 

100-0                    82-8 

54 

... 

92-2 

55-4 

ibo-o 

CHAPTER  V. 


SPECIFIC    GRAVITY    AND    VISCOSITY. 
SPECIFIC  GRAVITY  OF  OILS,  FATS,  &c. 

INASMUCH  as  the  majority  of  natural  oils,  fats,  and  similar  sub- 
stances are  mixtures  of  more  than  one  constituent,  the  relative 
proportions,  and  even  the  nature  of  the  ingredients  being  subject 
to  some  degree  of  variation,  it  results  that  the  general  physical 
characters  of  any  given  oil,  £c.,  are  liable  to  fluctuation  within 
certain  limits.  This  is  particularly  the  case  with  the  specific 
gravity  of  such  materials,  differences  in  the  climate  and  soil 
in  which  seed-bearing  plants  are  grown,  in  the  degree  of  culti- 
vation and  the  maturity  of  the  crop,  and  such  like  causes 


SPECIFIC    GRAVITY.  77 

often  producing  measurable  differences  in  the  relative  density  of 
the  oil  extracted  ;  as  also,  to  some  extent,  does  the  method 
of  extraction  adopted,  the  first  runnings  obtained  by  pres- 
sure in  the  cold  being  often  perceptibly  lighter  bulk  for  bulk 
than  those  obtained  later  by  hot  pressure.  In  similar  fashion, 
variations  in  the  particular  breed  of  animal  (e.g.,  in  the  case  of 
oxen  and  sheep),  the  part  of  the  body  from  which  the  fat  is 
extracted,  the  mode  of  feeding,  &c.,  often  correspond  with  ana- 
logous fluctuations  in  the  case  of  animal  fats ;  added  to  which, 
the  method  of  refinement  adopted  and  the  degree  of  purification 
effected,  cause  variations  in  proportion  to  the  amount  of  residual 
mucilaginous  or  albuminous  matters  left  unremoved  ;  whilst  the 
age  of  the  sample  is  often  a  material  point,  many  kinds  of  oil 
having  a  tendency  to  absorb  oxygen  from  the  air,  thereby 
becoming  more  dense. 

Notwithstanding  these  sources  of  variation,  however,  it  is 
often  possible  to  obtain  useful  information  as  to  the  freedom  or 
otherwise  of  oils,  tfcc.,  from  admixture  with  adulterating  sub- 
stances by  examining  their  specific  gravity  ;  or,  in  many  cases, 
preferably,  the  specific  gravity  of  the  free  fatty  acids  obtainable 
from  them  by  saponification.  This  determination  is  most  accur- 
ately effected  by  means  of  the  pyknometer*  (specific  gravity 
bottle);  but  since,  excepting  in  comparatively  few  special  cases 
(e.g.,  butter  analysis),  a  very  high  degree  of  accuracy  is  unneces- 
sary on  account  of  the  possible  natural  fluctuations  in  density, 
simpler  instruments  are  in  most  cases  sufficient  for  the  purpose 
in  view,  more  especially  when  checked  or  "calibrated,"'  as  de- 
scribed below.  Thus  for  most  fluid  oils  the  indications  of  a 
fairly  well  made  areometer  (hydrometer),  used  at  a  standard 
temperature,  are  sufficiently  accurate  ;  whilst  either  for  ordinary 
temperatures  or  for  more  elevated  ones,  the  hydrostatic  balance 
is  extremely  convenient.  In  using  this  latter  instrument  at 
higher  temperatures  (e.g.,  near  that  of  boiling  water V  it  should 
not  be  forgotten  that  if  the  plummet  immersed  in  the  liquid  to 
be  examined  (as  shown  in  Figs.  11  and  12)  be  made  of  glass,  it 
will  displace  more  than  0'2  per  cent,  (or  upwards  of  2  per  mille) 
more  fluid  at  near  the  boiling  point  of  water  than  at  15°  f  ;  so 
that  if  originally  constructed  to  give  accurate  indications  at  15°, 
the  values  indicated  at  near  100°  will  be  more  than  2  per  mille 
too  high  on  account  of  the  greater  displacement ;  whence,  in  the 

*  For  a  description  of  some  highly  accurate  forms  of  this  instrument  and 
their  moie  of  use,  together  with  a  discussion  of  the  corrections  indispens- 
able when  results  are  required  to  be  accurate  to  a  unit  in  the  fourth 
decimal  place  (±  O'OOOl),  and  a  fortiori  to  one  in  the  fifth  place  (±  O'OOOOl), 
vide  a  paper  by  the  author,  Journ.  Soc.  C/iem.  Industry,  1892,  p.  297. 

t  The  cubical  coefficient  of  expansion  of  glass  is  near  '000025  =  —      -  ; 

'rL/jUiJiJ 

so  that  a  rise  of  temperature  of  85°  represents  an  increment  in  volume  of 

o~ 

=  2-125  per  mille. 


78  OILS,    FATS,    WAXES,    ETC. 

Cease  of  fluid  oils,  the  specific  gravity  of  which  is  usually  from 
•9  to  -95,  the  indications  at  near  100°  will  be  close  to  -002  too 
high.  Analogous  errors  of  excess  apply  to  all  glass  araeometers 
and  pyknometers  when  graduated  at  one  temperature  and  used 
at  a  higher  one. 

Another  matter  to  be  remembered  is  that  the  numerical  value 
arrived  at  expresses  different  things,  according  as  the  water  with 
which  the  instrument  is  graduated  is  at  one  temperature  or 
another ;  this  applies  equally  to  the  indications  of  the  pyk- 


Fig.  11. 

nometer,  the  araeometer,  and  the  hydrostatic  balance.  When 
the  indications  represent  the  ratio  between  the  weight  of  a  given 
volume  of  substance  and  that  of  the  same  weight  of  water,  both 
at  the  same  temperature  t°,  the  value  is  the  specific  gravity  at  t°  ; 
thus  the  specific  gravity  at  100°  of  a  given  oil  or  melted  wax  is 
the  weight  of  a  given  volume  of  substance  compared  with  that  of 
the  same  weight  of  water  also  at  100°.  If,  however,  the  oil  be 
at  t°,  and  the  water  at  a  different  temperature,  T,  the  value  is 
neither  the  specific  gravity  at  t°  nor  that  at  T.  If  T  =  4°  C.,  the 
value  is  the  weight  in  grammes  att°of\  c.c.  of  oil,  since  at  4°  C. 
1  c.c.  of  water  weighs  1  gramme  ;  this  value  is  often  considerably 
different  from  the  specific  gravity  of  the  oil  at  £°,  the  more  so 
the  higher  the  value  of  t ;  thus  if  t  =  100°  0,  since  1  c.c.  of  water 
at  100°  weighs  0-9586  gramme,  the  weight  of  1  c.c.  of  oil  at  100° 
will  be  only  0-9586  times  the  specific  gravity  of  the  oil  at  100°  ; 
i.e.,  the  latter  value  is  more  than  4  per  cent,  in  excess  of  the 


SPECIFIC    GRAVITY.  79 

former  one.  Unfortunately,  most  observers  have  recorded  their 
results  in  neither  of  these  two  forms,  but  have  used  a  mode  of 
expression  where  T  is  not  4°,  and  is  not  =  t.  Tne  result  thus 
expressed  is  the  relative  density  of  water  at  t  referred  to  water 

at  T,  sometimes  expressed  as  the  relative  density  at    -  -  ;  when 

T  =  15° -5  C.,  a  temperature  frequently  chosen,  this  value'  repre- 
sents 1-0009  times  the  weight  of  1  gramme  of  oil  at  ^  since 
1  c.c.  of  water  at  15*5  weighs  '9991  gramme. 


Fig.  12. 

Lefebre's  Oleometer. — Fig.  13  represents  Lefebre's  araeo- 
meter, especially  intended  for  oils  the  specific  gravity  of  which 
at  15° -5  ranges  from  0*9  to  0*95  ;  the  instrument  is  so  graduated 
that  the  specific  gravity  is  directly  read  off  when  immersed  in  a 
fluid  at  the  standard  temperature  of  15° -5  ;  at  various  points  the 
average  specific  gravities  of  normal  oils  of  different  kinds  are 
marked  off  (linseed  oil,  olive  oil,  (fee.);  usually,  to  save  figures, 
only  the  second  and  third  decimal  places  are  given — i.e.,  35 
indicates  '935,  8  represents  -908,  and  so  on.  If  the  tempera- 
ture differ  slightly  from  the  normal  one  of  15° -5,  a  correction  is 

2 
made  by  adding    (or  subtracting)  -     x   -001  for  every  degree  of 

o 

temperature  above  (or  below)  the  standard,  this  correction  being 
based  on  the  fact  that  most  oils  expand  on  heating  to  nearly  the 
same  extent,  so  that  the  specific  gravity  becomes  lowered  by 
about  -00068  per  1°  C.  (vide  p.  93). 


80 


OILS,    FATS,    WAXES,    ETC. 


Fig.  13. 


When  it  is  required  to  deter- 
mine the  specific  gravity  of  an  oil, 
&c.j  at  a  temperature  somewhat 
elevated  (say  at  near  100°),  some 
form  of  heating  arrangement  must 
be  employed,  whereby  the  vessel 
containing  the  oil,  <fcc.,  can  be 
constantly  maintained  at  the  re- 
quired temperature  for  some  time. 
Fig.  12  illustrates  a  form  of  hot 
waterbath  thus  used  for  a  West- 
phal  hydrostatic  balance. 

When  temperatures  other  than 
100°,  but  higher  than  the  ordi- 
nary atmospheric  temperatures 
are  required,  the  hot  air  arrange- 
ment indicated  by  Fig.  1 4  may  be 
employed ;  in  this  case  the  vessel, 
C,  containing  the  oil,  tfec.,  to  be 
examined,  is  heated  by  a  hot  air 
bath,  B,  the  ascending  hot  gases 
from  a  ring  burner  being  made  to 
circulate  as  indicated  by  the 
arrows.  The  temperature  of  the 
inner  hot  air  space  is  shown  by 
the  thermometer,  D,  and  should 
not  differ  much  from  that  of  the 
oil  itself,  as  indicated  by  a  ther- 
mometer immersed  therein  (in 
the  figure,  as  also  in  Fig.  12,  this 
is  enclosed  inside  the  plummet*). 
A  thermostat,  or  heat  regulator 
where  the  gas  supply  is  auto- 
matically regulated,  should  be 
employed  in  addition. 

Fig.  15  represents  Ambuhl's 
arrangement  where  the  vessel 
containing  the  oil  is  heated  in  a 
current  of  vapour  (steam  from 
boiling  water,  or  other  vapour 
emitted  by  a  fluid  of  convenient 
boiling  point). 

*  Fletcher  has  recently  constructed  a 
thermohydrometer,  consisting  of  an  ordi- 
nary arteometer  with  enclosed  thermo- 
meter, so  as  to  read  off  the  temperature 
of  the  fluid  examined  simultaneously 
with  the  indicated  relative  density. 


SPECIFIC   GRAVITY. 


81 


Fig.  14. 


Fig.  15. 


82 


OILS,    FATS,    WAXES,    ETC. 


In  the  Paris  Municipal  Laboratory,  a  peculiar  kind  of 
"  thermal  araeometer,"  constructed  by  Langlet,  is  in  use  for  the 
examination  of  olive  oil.  This  is  an  araeometer  with  an  internal 
thermometer,  so  adjusted  that  when  the  instrument  is  placed  in 
pure  olive  oil,  the  level  of  the  fluid  indicated  on  the  stem  and 
the  thermometer  reading  are  practically  the  same ;  if  the  oil  be 
warmed  so  as  to  become  lighter,  the  hydrometer  sinks  to  an  in- 
creased depth,  and  the  thermometer  column  rises  through  the 
same  length,  so  that  the  two  readings  always  correspond.  If, 
however,  the  oil  be  not  genuine  olive  oil,  but  contain  an  admixture 
of  other  oil  of  different  density,  the  readings  will  not  agree.  Thus, 
the  following  pairs  of  readings  correspond  with  certain  oils  other 
than  olive  oil  and  various  mixtures  (Muntz) : — 


Thermometer 
Reading. 

Reading  on 
Stem. 

Degrees  C. 

Degrees  C. 

18-9 

11-0 

Cotton  seed  oil,  . 

,                 ,                 .                 *                 * 

18-9 

10-5 

3  Parts  olive  oil  to 

1  of  cotton  seed  oil, 

18-1 

16-1 

2 

1 

18-6 

15-8 

3 

1  of  sesame  oil, 

18-3 

16-5 

2 

1 

18-6 

16-1 

3 

1  of  colza  oil, 

18-3 

18-5 

3 

1  of  earthnut  oil, 

18-1 

17-2 

2 

1 

18-7 

17-5 

52                              4 

8              ,, 

187 

17-4 

CONSTRUCTION   OF   TABLES   OF   ERRORS   FOR 

HYDROMETERS  AND  HYDROSTATIC 

BALANCES. 

Hydrometers,  as  usually  sold,  are  not  infrequently  affected  by 
errors  of  construction  and  graduation,  sufficiently  great  to  render 
their  indications  inexact  to  at  least  ±  one  unit  in  the  third 
decimal  place,  and  sometimes  much  more,  quite  apart  from  any 
error  arising  from  the  difficulty  of  reading  off  the  exact  level. 
To  do  this  with  as  little  error  as  possible,  the  hydrometer  should 
be  floated  in  a  jar  with  a  white  strip  of  enamel  at  its  back,  or  a 
strong  light  so  placed  that  the  lowest  point  of  the  meniscus 
formed  by  the  upper  part  of  the  fluid  can  be  read  off  on  the 
hydrometer  scale.  Unless  the  fluid  examined  be  excessively 
dark  coloured,  this  can  generally  be  done  pretty  readily,  the  eye 
being  level  with  the  bottom  of  the  meniscus  (as  in  reading  a, 
burette). 

To  eliminate,  as  far  as  possible,  errors  of  graduation,  it  is 


SPECIFIC    GRAVITY. 


83 


necessary  to  construct  for  each  instrument  a  table  of  errors, 
deduced  by  directly  comparing  at  the  same  temperature  the 
values  obtained  with  different  fluids  simultaneously  examined 
by  means  of  an  accurate  pyknometer,  and  with  the  hydrometer. 
The  following  illustration  will  suffice  to  indicate  the  mode  of 
construction  of  such  a  table  of  errors  for  a  hydrometer  intended 
to  show  at  15° '5  C.  values  ranging  between  '900  and  "950 ;  when 
such  a  table  is  carefully  prepared,  the  corrected  reading  of  a 
tolerably  sensitive  hydrometer  should  be  exact  within  ±  two, 
or  even  ±  one  unit  in  the  fourth  decimal  place.  The  figures  are 
expressed  on  the  thousandfold  scale,*  three  comparisons  being 
made  respectively  near  the  top,  middle,  and  bottom  of  the  hydro- 
meter scale. 


True  Specific  Gravity 
at  15°  -5  by  Pyknometer. 

Hydrometer  Reading 
at  15°  5. 

Difference. 

948-4 
•     924-7 
901-1 

947-5 
925-0 
902-5 

+  0-9 
-  0-3 
-  1-4 

From    these   comparisons   the   following   table   of    errors    is 
deduced  by  interpolation  :  — 


Hydrometer  Reading 
at  ii>0-5. 

Correction  to  be  added 
to  obtain  the  True 
Specific  Gravity. 

Corrected  Specific 
Gravity  at  15°-t;. 

900-0 

-  1-50 

898-5 

905-0 

-  1-25 

903-75 

910-0 

-  TOO 

909-0 

915-0 

-  0-75 

914-25 

920-0 

-  0-50 

919-5 

925-0 

-  0-30 

924-7 

930-0 

-  0-05 

929-95 

935-0 

+  0-20 

935-2 

940-0 

+  0-45 

940-45 

945-0 

+  0-75 

945-75 

950-0 

+  i-oo 

951-0 

In  similar  fashion,  a  table  of  errors  may  be  constructed  for  a 
hydrostatic  balance ;  thus,  the  following  numbers  were  obtained 
with  such  an  instrument  of  fairly  good  construction,  the  values 
being  here  expressed  on  the  ordinary  scale,  and  not  multiplied 
by  1,000,  the  temperature  throughout  being  15°-5: — 

*  To  save  decimals,  specific  gravity  values  are  often  quoted  after  multi- 
plication by  1,000  :  thus,  an  oil  of  specific  gravity  0'967  is  said  "  to  have 
the  gravity  967,"  and  so  on. 


OILS,    FATS,    WAXES,    ETC. 


True  Specific  Gravity 
by  Pyknometer. 

Value  indicated  by 
Hydrostatic  Balance. 

Difference. 

0-9976 
0-9517 
0-9098 
0-8524 

0-9995 
0-9530 
0-9100 
0-8520 

-  0-0019 
-  0-0013 
-  0-0002 
+  0-0004 

From  these  determinations   the  following  table  of  errors  is 
calculated  by  interpolation  : — 


Speciflc  Gravity 
indicated  by 
Hydrostatic  Balance. 

Correction  to  be  added 
to  obtain  the  True 
Speciflc  Gravity. 

Corrected  Speciflc 
Gravity. 

0-85 

+  -0004 

•8504 

0-86 

+  -0003 

•8603 

0'S7 

+  -0002 

•8702 

0-88 

+  -oooi 

•8801 

0-89 

0 

•8900 

0-90 

-  -oooi 

•8999 

0-91 

-   -0002 

•9098 

0-92 

-  -0005 

•9195 

093 

-  -ooos 

•9292 

0-94 

-  -0010 

•9390 

0-95 

-   -0013 

•9487 

0-96 

-   -0014 

•9586 

0-97 

-   -0015 

•9685 

0-98 

-  -0017 

•9783 

0-99 

-   -0018 

•9882 

1-00 

-  -0019 

•9981 

Considerably  larger  corrections  than  most  of  those  indicated  in 
this  table  have  sometimes  to  be  applied  to  instruments  as 
purchased,  in  order  to  deduce  the  true  specific  gravities  from  the 
direct  results  of  observation. 

Hydrometer  Scales. — A  considerable  number  of  more  or 
less  arbitrary  scales  for  araeometers  are  in  use,  a  circumstance 
often  leading  to  much  practical  inconvenience.  The  simplest  or 
"gravity"  scale  is  that  where  the  specific  gravity  of  the  fluid 
is  directly  indicated  by  the  level  to  which  the  instrument  sinks 
in  the  fluid  (at  the  normal  temperature) — e.g.,  in  Lefebre's 
oleometer  (p.  80).  Twaddell's  scale  is  not  much  inferior  in 
simplicity,  each  degree  on  that  scale  representing  an  alteration 
of  5  units  in  gravity  on  the  thousandfold  scale  (p.  83),  and  the 
valuation  being  given  by  the  formula 

S  =  1000  +  5n, 

where  S  is  the  specific  gravity  on  the  thousandfold  scale,  and  n 
the  hydrometer  reading ;  thus  10°  T  represents  specific  gravity 


SPECIFIC   GRAVITY. 


85 


1-050;  100°  T,  specific  gravity  1-500;  150°  T,  specific  gravity 
1*750  ;  and  so  on.  The  same  rule  applies  in  the  case  of  a  fluid 
having  a  density  less  than  that  of  water,  the  value  of  n  being 
then  negative,  so  that  if  n  =  —  10°  T,  the  specific  gravity  would 
be  '950,  and  so  on ;  the  negative-scale  Twaddell  hydrometer, 
however,  is  but  rarely  used.  A  variety  of  other  scales  are  also 
in  use,  more  especially  in  different  parts  of  the  Continent ;  the 
following  table  of  formulae  is  given  by  Benedikt,  expressing  the 
relative  values  of  their  degrees,  S  and  n  having  the  same  mean- 
ings as  above : — 


Araeometer  of 

Temperature. 

Fluids  Heavier  than 
Water. 

Fluids  Lighter  than 
Water. 

Balling,  . 
Beaume, 
Beaume,* 
Beaume,  t 
Beck,       . 
Brix, 
Cartier,  . 
Fischer,  . 
Gay  Lussac,+  . 
E.  G.  Greiner, 
Stoppani,§ 

Degrees. 

17  '5  C. 
12  -5  C. 
15-0  C. 
17  "5  C. 

12  -5  C. 

/12-5R. 
\15-625C. 

12  -5  C. 

/12-5R. 
\15-625C. 

4C. 

/12-5R. 
\15-625C. 

/12-5R. 
\15-625C. 

«           200 

200 

200  -  n 
144 

"  200  +  M 
144 

144  -  n 
144-3 

134  +  n 
144-3 

144-3  -  n 
146-78 

134-3  +  n 
s          146-78 

-  146-78  -  n 

170 
=  l70"^i 

400 

136-78  +  n 

o          170 
170  +  n 

c          400 

~  400  -  n 

400 
400  -  n 

100 

o  =    

n 
400 

400  +  n 
Q          136-8 

126-1  +  n 

400 

400  +  n 

s  =  ioo 

n 
400 

400  -  n 
166 

400  +  n 
166 

166  -  n 

166  +  n 

*S=  -.70  :—    for  lighter  fluids  (Schadler). 

-1  44  «">   T"  ?/• 

f  S  =  ul*7S+  n  for  Hghter  fluids  (SchUdler). 


re  for  heavier  fluids,  and  =  jggqp-  for  lighter  ones  (Schadler) 


S  =  j 
§  S  =  ,-7.7,  --  -  for  heavier  fluids,  and  =  j^-  —  for  lighter  ones  (Schadler). 


160  —  n 


160  +  n 


A) 

o 


and   Hurter  (Alkali  Maker's  Pocket-book)   regard  the 

144-3 


36  OILS,    FATS,    WAXES,    ETC. 

Lunge 

series  of  values  got  by  means  of  the  formula  S  =    . 

144-3  -  n 

as  the  only  "  rational "  one  of  the  various  Beaume  scales  in 
use;  taking  the  formula  at  15°  C.,  the  specific  gravity  of 
water  at  15°  =  0°  B. ;  whilst  66°  B.  represents  specific  gravity 
144-3 


=  1-8426. 


The  following  table  exhibits  the  relation- 


144-3  -  66 

ships  between  the  values  of  "  rational "  Beaume  degrees,  Twaddell 

degrees,  and  true  specific  gravity  : — 


Beaume. 

Twaddell. 

Specific  Gravity. 

Beaumd. 

Twaddell. 

Specific  Gravity. 

0 

0 

1-000 

36  -Q 

66-4 

•332 

0-7 

1-0 

1-005 

38 

71-4 

•357 

1-0 

1-4 

1-007 

40 

76-6 

•383 

1-4 

2-0 

1-010 

42 

82-0 

•410 

2-0 

2-8 

1-014 

44 

87-6 

•438 

2-7 

4-0 

1-020 

46 

936 

•468 

4-0 

5-8 

1-029 

48 

99-6 

•498 

5-0 

7'4 

1-037 

50 

106-0 

•530 

6-7 

10-0 

1-050 

52 

112-6 

•563 

80 

12-0 

1-U60 

54 

119-4 

•597 

10-0 

15-0 

1-075 

56 

127-0 

•635 

14-0 

21-6 

1-108 

58 

134-2 

•671 

16-0 

25-0 

1-125 

60 

142-0 

•710 

18-8 

30-0 

1-150 

61 

146-4 

•732 

20-0 

32-4 

1-362 

62 

150-6 

•753 

23-0 

38-0 

1-190 

63 

155-0 

•775 

25-0 

42-0 

1-210 

64 

159-0 

•795 

27-0 

46-2 

1-231 

65 

164-0 

1-820 

30-0 

52-6 

1-263 

66 

J68-4 

1-842 

33'0 

59-4 

1-297 

67 

173-0 

1-865 

RELATIVE  DENSITIES  OF  THE  PRINCIPAL 
OILS,  FATS,  <fec. 

Many  experimenters  have  published  the  results  of  their  deter- 
minations of  the  specific  gravities  of  genuine  oils,  &c. ;  in  most 
instances  the  observed  limits  of  variation  in  this  respect  are  not 
very  wide,  being  mainly  dependent  on  the  freedom  from  rancidity 
and  free  fatty  acids ;  the  degree  of  refinement  (or  freedom  from 
mucilaginous  matter,  &c.) ;  the  age  of  the  sample  (whether 
oxygen  has  been  absorbed  or  not),  and  so  on.  In  many  cases  a 
measurable  difference  is  observable  between  the  density  of  the 
oil  first  expressed,  especially  when  cold  drawn,  and  that  of  the 
later  portions  obtained  by  the  aid  of  heat,  the  latter  being 
generally  heavier.  The  following  figures  are  given  by  Schadler 


SPECIFIC    GRAVITY. 


87 


as  expressing  the  average  values  of  the  specific  gravities  at  15° 
of  a  large  number  of  the  more  commonly  occurring  vegetable  and 
other  oils  : — 


Name  of  Oil. 

Oil  from  Seed  of 

Specific 
Gravity 
at  15°. 

Almond  oil, 

Amygdalus  communis, 

•9190 

Arachis  oil  (earthnut  oil),    . 

Arachis  hypogsea, 

•9202 

Bassia  fat  (Illipe  butter),    . 

Bassia  longifolia,  Roxb., 

•9580 

Ben  oil,       .... 

Moringa  oleifera, 

•9120 

Belladonna  seed  oil,    . 

Atropa  belladonna, 

•9250 

Beechnut  oil, 

Fagus  sylvatica, 

•9225 

Camelina  oil  (gold  of  pleasure), 

Camelina  sativa, 

•9328 

Cacao  butter, 

Theobroma  cacao, 

•9000 

Castor  oil,  .... 

Ricinus  communis, 

•9667 

Cokernut  oil, 

Cocos  nucifera, 

•9250 

Colza  oil,     . 

Brassica  campestris, 

•9150 

Cotton  seed  oil  (raw), 

Gossypium  herbaceum, 

•9224 

,,            (refined),     . 

»                » 

•9230 

Cro^on  oil, 

Croton  tiglium, 

•9550 

Euonymus  oil  (spindel  oil), 

Euonymus  europseus, 

•9380 

Grape  seed  oil,    . 

Vitis  vinifera, 

•9202 

Hemp  seed  oil,    . 

Cannabis  sativa, 

•9276 

Gourd  seed  oil,    . 

Cucurbita  pepo, 

•9251 

Hazelnut  oil, 

Corylus  avellana, 

•9154 

Linseed  oil  (raw), 

Linum  usitatissimum, 

•9299 

(boiled),     . 

99                               99 

•9411 

Melon  seed  oil,    . 

Cucurbita  pepo, 

•9251 

Madia  oil,   .... 

Madia  sativa, 

•9350 

Mustard  oil, 

Sinapis  nigra, 

•9182 

Maize  oil,    .... 

Zea  mais, 

•9210 

Nut  oil  (walnut  oil),  . 

Juglans  regia, 

•9260 

Nutmeg  oil, 

Myristica  moschata, 

•9480 

Olive  oil  (greenish  yellow), 

Olea  europsea, 

•9144 

„      (best  quality), 
,,      (Galipoli),     . 

>»           »« 
»>           >» 

•9177 
•9196 

Pine  oil  (red  pine  seed  oil  ;  "1 
pinaster  seed  oil),   .        .  / 

Pinus  picea, 

•9285 

Palm  oil,     .... 

Elais  guinensis,  &c., 

•9046 

Poppy  seed  oil,  . 
Yellowhorn  poppy  oil, 

Papaver  somniferum, 
Papaver  glaucium, 

•9245 
•9250 

Plum  kernel  oil,           .         .          Prunus  domestica, 

•9127 

Radish  seed  oil,  .         . 

Raphanus  sativus, 

•9162 

Rape  oil,     .... 
Red  rape  oil, 
Winter  rape  oil, 

Brassica  napus  oleifera, 
Hesperis  matronalis, 
Brassica  rapa  olifera  biennis, 

•9157 
•9282 
•9154 

,,             (refined),     . 

»                                        5  > 

•9177 

Sesame"  oil, 

Sesamum  orient/ale, 

•9235 

Sunflower  seed  oil, 

Helianthus  annuus, 

•9262 

Tobacco  seed  oil, 

Nicotiana  tabacum, 

•9232 

Weld  seed  oil,    . 

Reseda  luteola, 

•9358 

88 


OILS,    FATS,    WAXES,    ETC. 

ANIMAL  OILS,   &c. 


Name  of  Oil. 

Source. 

Specific 
Gravity 
at  15°. 

Bone  fat,     .... 
Cod  liver  oil, 
(purified), 
,,             (Labrador), 
Mutton  tallow,    . 
Seal  oil,      .... 

Bones, 
Gadus  morrhua,  &c., 
»>              >  » 

Sheep, 
Phoca  vitulina,  &c., 

•9185 
•9200 
•9270 
•9237 
•9147 
•9246 

,,     (purified), 
Sperm  oil,  .... 
Whale  oil  (train  oil),  . 
,,       (white), 

Physeter  macrocephalus, 
Balsena  mysticetus, 

•9261 
•9115 
•9250 
•9258 

The  following  determinations  of  the  specific  gravity  at  15°  of 
various  solid  fats,  &c.,  are  given  by  Hager  and  Dieterich  : — 


Hager. 

Dieterich. 

Beef  tallow, 

•925  to  -929 

•952  to  -953 

Sheep's  tallow,     . 

•937  to  -940 

•961 

Hog's  lard,  . 

•931  to  -932 

Stearine, 

... 

•971  to  -972 

Stearic  acid  (fused),      . 

•964 

,,         (crystallised), 

•967  to  -969 

m 

Butter  fat  (clarified),    . 

•938  to  -940 

„       (several  months  old), 

•936  to  -937 

Artificial  butter, 

•924  to  -930 

Cacao  butter  (fresh),     . 

•950  to  -952 

•980  to  -9S1 

,  ,             (very  old), 

•945  to  -946 

Beeswax  (yellow), 

•959  to  -962 

•963  to  -964 

„       (white), 

•919  to  -925 

•973 

Japanese  wax, 

•977  to  -978 

•975 

,,             (very  old), 

•963  to  -964 

... 

Spermaceti, 

... 

•960 

Colophony  (American), 

1-100 

1-108 

,,          (French),     . 

1-104  to  1-105 

Galipot  resin  (purified), 

1-045 

Crude  ozokerite,   . 

•952 

Ceresin  (yellow), 

•925  to  -928 

•922 

„       (half  white),     . 

•923  to  -924 

•920 

,,       (pure  white),    . 

•905  to  -908 

•918 



The  following  valuations  of  specific  gravity  at  37° '8  C.  =  100°  F. 
are  given  by  Muter  *  : — 


*  Spon's  Encyclopaedia  of  Arts  and  Manufactures,   ii.,   p.  1,469.     The 
values  quoted  are  the  numbers  expressing  the  weights  of  given  volumes  of 


SPECIFIC   GRAVITY. 


89 


Oil. 

Limits  of  Specific  Gravity. 

Average. 

•8980  to 
•9073 
•9550 
•9103 
•9170 
•9130 
•9114 
•9173 
•9190 
•9076 
•9232 
•9320 
•9052 
•9080 
•9052 
•9150 
•9060 
•9053 
•9136 
•8672 
•9056 

•9109 
•9020 
•9576 
•9152 
•9197 
•9140 
•9220 
•9180 
•9  i95 
•9082 
•9300 
9440 
•9079 
•9090 
•9079 
•9155 
•9077 
•9065 
9195 
•8963 
•9066 

•9056 
•9085 
•9558 

•9176 
•9136 
•9176 
•9179 
•9193 
•9078 
•9252 
•9380 
•9070 
•9085 
•9070 
•9154 
•9067 
•9067 
•9179 
•8724 
•9060 

Arachis  (groundnut)  oil, 
Castor,  

Cotton  seed  (brown),     . 
,,          (refined  —  salad  oil),  . 
Cod  fish  oil,   

Lard  oil,         ..... 

»       (boiled)  
Neat's  foot,    
Nut,       

Olive,     

Rape,      
,,      refined  (Colza),    . 
Seal,       

Sperm,  
Whale,  

Since  1  c.c.  of  water  weighs  1-0000  grm.  at  4°,  -99908  at 
l5°-5,  and  -9933  at  37°'8,  these  values,  when  reduced  to  the 
standard  of  "specific  gravity  at  37'8  referred  to  water  at  15°'5" 

.     .       .    .,  ..       -9933 

be  ^ess  m  the  proportion  -7^onQ  — 
* 


/        .fl  .37°-8\ 

I  specific  gravity  at  -f  K'^E  )  > 
\  lo  "O/ 


i.e.,  less  by  0'58  per  cent.  ;  that  is,  less  by  from  -0051  to  -0056. 
If  reduced  to  the  standard  of  "  weight  at  37°'S  in  grins. 

*9933 
per  c.c.,"  tney  will  be  less  in  the  proportion  y^/^  —  *'•«•»  by  -67 

per  cent.  ;  that  is,  less  by  from  -0058  to  -0064. 

Classification  of  Oils  and  Fats,  &c.,  according  to  their 
Relative  Densities.—  The  following  tables  are  given  by  A.  H. 
Allen,*  exhibiting  the  general  classification  of  oils  and  fats,  &c., 
according  to  their  respective  densities  ;  the  relative  density  at 

99° 
15°  '5  being  taken  in  the  case  of  liquid  oils  and  that  at  pnr~  in 

the  case  of  fats,  &c.,  solid  or  nearly  so  at  ordinary  tempera- 
tures :  — 

oil  at  37°'8,  referred  to  the  weight  of  the  same  volume  of  water  at  the  same 
temperature  as  unity,  and  consequently  are  the  true  specific  gravities  at 
37  "8  (p.  78).  Muter,  however,  prefers  to  call  them  "  actual  densities  ;"  an 
unfortunate  term,  as  the  figures  are  very  different  from  the  true  densities. 

*  Commercial  Organic  Analysis,  vol.  ii.,  p.  89,  ct  seq. 


90 


OILS,    FATS,    WAXES,    ETC. 


OILS  LIQUID  AT  15°  C. 


Specific  Gravity  at  15°-5  C.  =  G0°  F. 

Class  of  Oil. 

•875  to  -884. 

•884  to  -912. 

•912  to  '920. 

•920  to  -937. 

•937  to  '970. 

Vegetable 
oils. 

None. 

None. 

Olive. 
Almond. 

Cotton 
seed. 

Japanese 
wood. 

Ben. 

Sesame. 

Croton. 

Arachis. 

Sunflower. 

Castor. 

Rape. 

Hazelnut. 

Linseed 

Colza. 
Mustard. 

Poppy  seed. 
Hemp  seed. 

(boiled). 
Blown  oils 

Linseed 

(manufac- 

(raw). 

tured). 

Walnut. 

Cokernut 

oleine 

(manufac- 

tured). 

Essentially 

More  or  less 

non-drying 

drying  oils. 

oils. 

Terrestrial 

None. 

None. 

Neat's  foot. 

None. 

None. 

Animal 

Bone. 

oils. 

Lard  and 

tallow 

oils  (manu- 

factured). 

Marine 

Sperm. 

None. 

Shark 

Whale. 

None. 

Animal 

Bottlenose. 

liver. 

Porpoise. 

oils. 

Seal. 

Menhaden. 

Cod  liver. 

Shark 

liver. 

Free  fatty 

None. 

Oleic  acid. 

Linolic 

Ricinoleic 

acids. 

acid. 

acid. 

Hydro- 
carbon 

Shale  pro- 
ducts. 

Shale  pro- 
ducts. 

Heavy 
Petroleum 

None. 

None. 

oils. 

Petroleum 

Petroleum 

products. 

products. 

products. 

SPECIFIC    GRAVITY. 


91 


OILS,  &c.,  PASTY  OR  SOLID  AT  15°*5C.  =  GOT. 
Arranged  according  to  their  Specific  Gravity  when  Melted. 


Relative  Density  at  ^~d* 

Class  of  Oil,  Ac. 

•750  to  -800. 

•800  to  -855. 

•8-55  to  '863.               •{  G3  to  '867. 

Vegetable 
fats. 

None. 

None. 

Palm  oil. 
Cacao  butter. 

Palmnut  oil. 
Cokernut  oil. 

Japan  wax. 

Myrtle  wax. 

Cokernut  and 

Cotton  seed 

steariiie 

(manufac- 

tured). 

Animal  fats. 

None. 

None. 

Tallow. 

Butter  fat. 

Lard. 

Suet. 

Dripping. 

Bone  fat. 

Oleomar- 

garine 

and  Butterine 

(manufac- 

tured). 

Vegetable 
and  Animal 

None. 

Spermaceti. 
Beeswax. 

None. 

None. 

waxes. 

Chinese  wax. 

Carnauba 

wax. 

Free  fatty 

None. 

Stearic  acid. 

None. 

None. 

acids. 

Palmitic  acid. 

Oleic  acid. 

Hydro- 

Paraffin wax. 

Shale  pro- 

Vaseline. 

None. 

carbons. 

Ozokerite. 

ducts. 

Petroleum 

products. 

*  These  relative  density  values  were  mostly  taken  with  the  plummet 
apparatus  (Westphal's  hydrostatic  balance)  and  not  corrected  for  the 
expansion  of  the  glass  plummet  used ;  many  of  the  values  are,  therefore, 
about  0'2  per  cent,  too  high — ».e.,  too  high  by  nearly  *002  (p.  77). 


92 


OILS,    FATS,    WAXES,    ETC. 


Rosin  oils  and  rosin  are  not  included  in  these  tables,  these 
substances  having  specific  gravities  mostly  higher  than. any 
therein  mentioned — viz.,  from  '97  to  upwards  of  I'O;  similar 
remarks  apply  to  some  of  the  highest-boiling  petroleum  and  shale 
hydrocarbons. 

Variation  of  Density  of  Oils,  &c.,  with  Temperature.— 
Like  most  other  substances,  oils  and  melted  fats,  ttc.,  expand 


i 

Ratio  of  Weight  of  a  given  Volume 

of  Substance  at  t°,  to  that  of  the     i        Mean 

same  Volume  of  Water  at  15°  5 

Variation 

Name  of  Oil  or  Fat,  &c. 

considered  as  1000. 

perl0 
Alteration  in 

Tempera- 

ture. 

J=15-5. 

*  =  40°-80°. 

/=98°-99°. 

Arachis  oil  (groundnut  oil),    . 
Beeswax,        .... 

922 

835-6  at  80° 

867-3 
822-1 

•66 
•75 

Butter  fat,      .... 

904-1  at  40s 

867-7 

•62 

Castor  oil,      .... 

965-5 

... 

909-6 

•65 

Cod  liver  oil,    "... 

927-5 

... 

874-2 

•65 

Cokernut  oleine,     .         .         . 

926-2 

... 

871-0 

•67 

Cokernut  stearine, 

... 

895  -9  at  60° 

869-6 

•67 

Cokernut  butter,    . 

911  '5  at  40° 

873-6 

•64 

Cotton  seed  oil, 

925 

872-5 

•63 

Doegling  oil  (bottlenose  whale), 

880-8 

827-4 

•64 

Japanese  wax, 

901  -8  at  60° 

875-5 

•69 

Lard,      

898-5  at  40° 

8608 

•65 

Linseed  oil,    .... 

935 

880-9 

•65 

Menhaden  oil, 

932 

877-4 

•65 

Neat's  foot  oil, 

914 

861-9 

•63 

Niger  seed  oil, 

927 

... 

873-8 

•64 

Palm  butter,  .... 

893-0  at  50° 

858-6 

•72 

Porpoise  oil,  .... 

926 

... 

871-4 

•65 

915 

863-2 

•62 

Seal  oil,          .... 

924 

873-3 

•62 

Sesame  oil,     .... 

921 

... 

867-9 

•62 

Spermaceti,    .... 

835  -Sat  60° 

808-6 

•72 

Sperm  oil,      .... 

883-7 

830-3 

•65 

Tallow,  

895'0  at  50° 

862-6 

•67 

Whale  oil,      .... 

930-7 

872-5 

•70 

Paraffin  wax, 

780-5  at  60° 

753-0 

•72 

Commercial    "stearine"          \ 
(crude  stearic  acid),  .         .  j 

... 

859-0  at  60° 

8305 

•75 

Commercial    "oleine"     (  im-  \ 
pure  oleic  acid),         .         .  / 

903-2 

848-4 

•66 

on  heating  ;  it  is  somewhat  remarkable  that  nearly  all  bodies  of 
this  description  expand  at  about  the  same  rate  (within  not  very 
wide  limits  of  departure  from  the  average),  so  that  1  c.c.  of 
substance  always  increases  to  about  1*00075  c.c.  by  rise  of  tem- 
perature of  1°  C.  The  effect  of  this  on  the  density  is  to  diminish 
it  in  the  inverse  proportion;  so  that  an  oil,  &c.,  the  specific 


SPECIFIC   GRAVITY.  93 

gravity  of  which  at  15°  is  from  '9  to  '95,  will  become  diminished 

•9  *95 

in  specific  gravity  to  i<0uU75  to  1.QQ()75  by  rise  of  1°  in  tempera- 
ture— i.e.,  the  diminution  in  the  specific  gravity  is  -00067  to 
•00071.  Thus  the  preceding  values  were  obtained  by  A.  H. 
Allen ;  *  for  the  sake  of  convenience,  and  to  avoid  decimals, 
all  the  figures  are  multiplied  by  1,000. 

From  these  values  it  results  that  whilst  glyceridic  oils  fluid 
at  the  ordinary  temperature  diminish  in  specific  gravity  between 
15°  and  98°  C.  at  close  to  the  average  rate  of  -64  per  1°  (uncor- 
rected  for  plummet  expansion  ;  somewhat  more  when  corrected), 
glycerides  of  higher  melting  point  (like  Japanese  wax  and  palm 
butter)  and  waxes  (beeswax,  spermaceti,  paraffin  wax)  diminish 
in  specific  gravity  at  a  slightly  higher  rate,  averaging  about  0*7 

per   1°.     In  all   cases,  however,    the    rate   is   sensibly  near   to 

2 

^   x   -001  per  1°  C.,  reckoned  on  the  usual  specific  gravity  scale 

(water  =1)  and  not  multiplied  by  1,000. 

Figures  closely  concording  with  these  have  been  subsequently 
obtained  by  other  experimenters  ;  thus  0.  A.  Crampton  f  found 
for  various  samples  of  lard,  lard  stearine,  beef  fat,  oleostearine, 
cotton  seed  oil,  and  olive  oil,  coefficients  of  expansion  between 
15°  and  100°  lying  between  -000715  and  '000797,  averaging  close 

15° 
to  -00075.     Since  the  relative  density  at  —  of  these  substances 

was  found  to  lie  between  -9065  and  -9220,  the  average  decrement 
in  density  per  1°  C.  rise  in  temperature  was  close  to  0-69  on  the 
thousandfold  scale.  W.  T.  Wenzell  found  J  that  olive  oil, 
mustard  seed  oil,  castor  oil,  sperm  oil,  and  cod  liver  oil  expanded 
to  almost  exactly  the  same  extent  in  each  case  between  16°*7  and 
44° -4  C.  (62°  and  112°  F.) ;  the  increment  in  bulk  being  2  per 
cent.,  all  the  substances  being  examined  in  the  same  dilatometer. 
This  represents  an  apparent  coefficient  of  expansion  per  1°  C. 
of  -00072,  which,  when  corrected  for  the  expansion  of  the  glass, 
becomes  -00075,  or  practically  the  same  figure  as  that  found  by 
Crampton ;  and  indicating  an  average  decrement  in  density 
per  1°  C.  rise  in  temperature  of  0-68  to  0-69.  On  the  other 
hand,  Lohmann  states  §  that  1,000  volumes  of  olive  oil  increase 

*  Commercial  Organic  Analysis,  vol.  ii.,  p.  17,  et  seq.  The  values  at 
the  higher  temperatures  were  mostly  obtained  by  a  plummet  apparatus 
(Westphal's  hydrostatic  balance),  and  not  corrected  for  the  expansion  of  the 
glass  plummet  used,  the  object  being  simply  to  make  comparative  estima- 
tions ;  hence  many  of  the  figures  in  the  last  column  are  somewhat  too  low 
by  about  -01  to  -02  (vide  p.  77). 

•^Journ.  Soc.  Chem.  Ind.,  1889,  p.  550  ;  from  Amer.  Chem.  J.,  11.,  p.  232. 

J  Analyst,  1890,  p.  14. 

§Schadler's  Technologic  der  Fette  und  Oele,  2nd  edition,  edited  by 
Lohmaun,  p.  91. 


94  OILS,    FATS,    WAXES,    ETC. 

by  0'83  volumes  for  1°  C.  rise  of  temperature ;  whilst  the 
analogous  increment  for  rape  oil  is  0*89,  and  for  train  oil,  I'OO; 
figures  perceptibly  higher  than  those  found  by  the  other  observers 
above  mentioned. 

YISCOSIMETRY. 

In  order  to  obtain  valuations  of  the  so-called  "  viscosity "  of 
oils,  &c.,  as  approximate  measurements  of  their  relative  lubricat- 
ing powers,  two  classes  of  methods  are  in  use — viz.,  those  where 
the  measurements  are  made  by  observing  the  mechanical  effects 
produced  by  applying  the  oil,  &c.,  between  two  conveniently 
arranged  surfaces  in  motion  with  respect  to  one  another;  and 
those  where  the  oil  to  be  examined  is  made  to  pass  through  a 
given  tube  or  orifice,  and  the  time  of  passage  of  a  known  quan- 
tity is  noted.  From  the  practical  point  of  view,  obviously  the 
most  valuable  measurements  of  the  kind  are  those  obtainable  by 
imitating  as  nearly  as  possible  the  conditions  under  which  the 
lubricant  is  to  be  used — i.e.,  the  power  of  overcoming  friction  is 
best  measured  by  a  testing  machine  precisely  similar  to  that  for 
which  the  lubricant  is  required ;  quick  moving  spindles,  rapidly 
revolving  axles  in  journal  boxes,  or  heavy  slow  moving  shaft- 
ing, &c.,  being  employed  as  occasion  requires.  Such  measure- 
ments, however,  can  only  be  properly  carried  out  in  compara- 
tively large  establishments,  and  are  not  at  all  adapted  for  use  in 
laboratories  where  the  chemical  nature  of  the  oils  is  investigated 
and  their  general  characters  tested ;  accordingly,  in  these  cases, 
methods  of  the  second  kind  are  now  usually  employed,  since  ex- 
perience has  shown  that  the  comparatively  small  sized  mechanical 
testing  machines  of  various  kinds  that  have  been  invented  for 
the  purpose  are  apt  to  give  results  more  discordant  amongst 
themselves,  and  less  faithfully  representing  the  actual  lubricating 
values  of  the  substances  examined,  than  those  obtained  by 
apparatus  for  the  determination  of  "  efflux  velocity  "  (incorrectly 
designated  "  viscosity  "). 

Of  the  numerous  simpler  forms  of  mechanical  testing  arrange- 
ments that  have  been  proposed,  one  of  the  earliest  (M 'Naught's 
pendulum  machine)  is  also  one  of  the  least  unsatisfactory ;  this 
consists  of  two  discs,  the  lower  one  provided  with  a  raised  edge 
and  attached  to  a  vertical  spindle  revolving  in  bearings,  the 
upper  one  resting  on  a  pivot.  The  space  between  the  two  discs 
is  filled  with '  the  oil  to  be  tested,  and  the  lower  one  made  to 
revolve  at  a  given  speed.  The  friction  due  to  the  oil  would  in 
time  cause  the  upper  disc  to  revolve  too ;  but  this  motion  is 
prevented  by  means  of  a  projecting  pin  in  contact  with  a 
pendulum.  In  consequence,  more  or  less  pressure  on  the  pen- 
dulum is  produced,  diverting  it  from  a  vertical  position;  the 
degree  of  displacement  affords  a  measure  of  the  resistance  of 
the  oil. 


VISCOSIMETRY. 


95 


Efflux  Method. — The  simplest  arrangement  for  making  com- 
parisons between  different  oils,  &c.,  as  regards  their  efflux 
velocities,  consists  of  an  ordinary  pipette 
filled  up  to  a  given  mark  on  the  stem 
with  the  oil  to  be  tested,  the  time  being 
noted  requisite  for  the  oil  to  run  out 
either  completely,  or  down  to  some 
lower  mark.  Fig.  16  represents  an  in- 
strument on  this  principle  devised  by 
Schiibler,  the  upper  part  of  the  pipette 
being  expanded  into  a  reservoir,  with  a 
scale  attached  indicating  the  level  to 
which  the  fluid  sinks  ;  for  comparative 
observations,  the  reservoir  is  filled  to  a 
given  level,  and  the  time  determined 
during  which  the  level  sinks  to  a  given 
extent,  (a)  in  the  case  of  the  substance 
tested,  (b)  in  the  case  of  some  other 
substance  taken  as  standard. 

The  time  ratio  thus  deduced  does  not 
represent  the  relative  time  for  equal 
weights,  but  that  for  equal  volumes ;  so  that 

ratio    for    equal    weights    the    value 


16. 


to   deduce    the 
must    be    multiplied 


by  -j?,  where  d±  is  the  relative  density  of  the  substance  examined,. 
al 

and  d.j  that  of  the  standard  substance.  Thus  if  the  substances 
contrasted  were  sperm  and  rape  oils,  and  the  respective  time& 
requisite  for  the  same  volume  to  flow  out  were  40  and  120 
seconds,  whilst  the  relative  densities  were  -880  and  -915  re- 
spectively, the  relative  efflux  rate  for.  equal  weights  would 
be 

h      d,_  J0_xj915  _ 

t2      ~dl      120  x  -880 

As  the  time  of  efflux  varies  markedly  with  the  temperature 
(usually  diminishing  as  the  temperature  rises),  such  comparisons. 
must  necessarily  be  made  under  constant  conditions  as  to  tem- 
perature. 

In  order  to  ensure  uniformity  of  temperature  in  different 
experiments  the  results  of  which  are  to  be  compared  together, 
the  vessel  containing  the  oil  may  be  conveniently  surrounded 
with  a  jacket  containing  water  or  melted  paraffin  wax.  Fig.  17 
represents  an  arrangement  of  the  kind  described  by  E.  Schmidr 
also  containing  a  device  for  maintaining  a  constant  pressure 
during  the  outflow,  instead  of  having  a  continually  varying 
"  head,"  as  in  Schiibler's  instrument.  The  vessel  containing  the 
oil,  A,  is  a  sort  of  pipette,  excepting  that  the  upper  end  consists 


96 


OILS,   FATS,    WAXES,    ETC. 


of  a  tube,  B,  passing  down  inwards  to  a  point,  F,  near  the  base 
of  the  expanded  part.    The  upper  end  of  B  is  closed  by  a  stopper, 


R 


Fig.  17. 

D,  so  that  when  the  stopper  is  in,  no  air  can  enter,  and,  con- 
sequently, no  oil  runs  out  at  G ;  but  on  removing  the  stopper  the 


VISCOSIMETRY. 


97 


oil  flows  out.  The  pipette  is  filled  by  removing  the  stopper, 
inverting  it  with  the  end  BD  immersed  in  the  oil,  and  sucking 
up  at  the  other  end,  G,  until  full,  when  it  contains  some  50  c.cs. 
The  stopper  being  replaced,  the  pipette  is  fixed  in  position  inside 
the  water  jacket,  heated  to  the  required  temperature  in  the 
ordinary  way  by  means  of  the  projecting  tube  ;  a  stirrer,  R,  with 
an  annular  plate  at  the  end  is  provided  ;  by  moving  this  up  and 
down  the  temperature  is  equalised.  When  the  required  tem- 
perature is  attained  the  stopper  is  withdrawn  and  the  time 
ascertained  requisite  for  a  given  volume  of  oil  to  run  out;  as 
long  as  the  level  of  the  oil  in  the  pipette  does  not  fall  below  F, 
the  pressure  or  "  head  "  under  which  the  oil  issues  at  G  is  mani- 


festly constant,  being  that  due  to  a  column  of  oil  of  length,  GF. 
By  employing  high-boiling  paraffin  oils,  <fec.,  in  the  water  jacket, 
the  relative  efflux  times  at  high  temperatures  can  thus  be  readily 
determined  for  various  oils. 

7 


98 


OILS,    FATS,    WAXES,    ETC. 


With  all  instruments  of  this  description  a  variable  amount  of 
friction  is  brought  into  play  as  the  oil  passes  through  the  efflux 
pipe,  especially  when  this  is  conical ;  so  that  varying  results  are 
often  obtained  with  different  instruments.  This  source  of  error 
is  best  avoided  by  doing  away  with  the  efflux  tube  altogether,, 
substituting  for  it  a  hole  drilled  in  a  plate  of  glass  or  agate. 

Redwood's  Efflux  Viscosimeter. — Figs.  18  and  19  repre- 
sent Boverton  Redwood's  form  of  viscosimeter,  consisting  of  an 
interior  silvered  copper  cylinder,  about  1^  ins.  diameter  and 
3^  ins.  deep>  containing  the  oil  to  be  examined ;  the  bottom 
of  this  is  furnished  with  an  orifice,  consisting  of  a  hole  bored 
through  an  agate  plate,  the  top  of  which  is  excavated  into  a 
hemispherical  cavity,  so  that  a  small  brass  sphere  attached  to  a 
rod  and  dropped  in  forms  a  sufficiently  tight  valve.  An  outer 


Fig.  19, 


jacket  is  provided  with  a  closed  copper  tube  projecting  therefrom 
downwards  at  an  angle  of  45°,  so  that  by  heating  this  "tail"  in  a 
Bunsen  or  spirit  lamp  flame,  the  temperature  of  the  liquid  (water, 
oil,  melted  paraffin  wax,  &c.)  in  the  jacket  can  be  raised  as 
required.  A  revolving  agitator  to  equalise  temperature  in  the 
jacket  is  provided,  with  a  thermometer  attached,  a  second  ther- 
mometer being  supported  in  the  oil  by  a  clamp  fixed  to  the 
cylinder.  The  whole  rests  on  a  tripod  stand  furnished  with 
levelling  screws.  The  constancy  of  initial  level  of  oil  inside  the 


VISCOSIMETRY. 


99 


cylinder  is  assured  by  means  of  a  gauge  consisting  of  a  small 
internal  bracket  with  upturned  point. 

When  an  observation  is  to  be  made  the  bath  is  filled  with 
water,  or  heavy  mineral  oil,  etc.,  and  heated  to  the  required  tem- 
perature. The  oil  to  be  tested  is  also  heated  to  this  temperature 
and  poured  in  until  the  level  of  the  liquid  just  reaches  the  point 
of  the  gauge.  A  narrow-necked  flask,  holding  50  c.cs.,  is  placed 
beneath  the  jet  immersed  in  a  liquid  at  the  same  temperature 
as  the  oil.  When  all  is  ready  the  ball-valve  is  raised  and  a 
stop-watch  started,  and  the  number  of  seconds  requisite  to  fill 


Fig.  21. 

the  50-c.c.  flask  noted,  care  being  taken  that  the  temperature 
does  not  fluctuate  during  the  time,  and  that  the  oil  is  per- 
fectly free  from  suspended  matter,  such  as  dirt  or  globules  of 
water. 

In  order  to  obviate  the  necessity  of  always  using  the  same 
volume  of  oil  (indispensable  in  order  to  end  with  the  same 
difference  of  level,  and  consequently  maintain  the  same  average 
head  or  pressure  throughout),  A.  H.  Allen  makes  an  addition 


100 


OILS,    FATS,    WAXES,    ETC. 


consisting  of  an  airtight  cover,  Fig.  20,  perforated  by  two  holes, 
one  of  which,  A,  is  furnished  with  a  tap,  B,  while  the  other  has 
another  tube  screwing  airtight  into  it.  This  tube,  C,  is  pro- 
longed on  two  sides  in  contact  with  the  agate  orifice,  whilst  the 
angles  of  the  inverted  V-shaped  slits  cut  on  each  side  terminate 
at  D,  exactly  1}  inches  higher.  The  cylinder  is  completely 
filled  with  oil  before  commencing  an  observation,  the  tap,  B, 
closed,  and  the  orifice  opened  till  the  oil  sinks  to  the  level  of  D 


Fig.  2>2. 

in  the  inner  tube.  Air  then  bubbles  regularly  in  at  D ;  when 
this  happens,  the  temperature  is  noted  and  the  oil  collected  in  a 
graduated  receiver.  Any  volume  from  10  to  50  c.c.  can  thus  be 
run  out,  as  the  oil  falls  in  the  upper  part  of  the  cylinder,  but  is 
maintained  constantly  at  the  level,  D,  in  the  inner  tube.  Five 
consecutive  valuations  of  10  c.c.  each  may  thus  be  made,  whilst 
50  c.c.  run  out. 


VISCOSIMETRY.  101 

Several  other  forms  of  viscosimeter  have  been  constructed  by 
other  experimenters,  based  on  the  efflux  principle.  Fig.  21 
represents  in  section  Engler's  instrument ;  a  slightly  modified 
form  of  this  by  Engler  and  Kiinkler*  is  largely  used  on  the 
continent.!  Fig.  22  represents  a  simple  form  recently  constructed 
by  G.  H.  Hurst.;  The  oil,  &c.,  to  be  examined  is  run  into  the 
innermost  vessel  up  to  a  given  height  determined  by  a  gauge- 
pin,  and  heated  up  to  the  required  extent  by  applying  a  Bunsen 
burner  or  spirit  lamp  to  the  heater  at  the  side,  connected  by  two 
tubes  with  the  water  reservoir  surrounding  the  oil  chamber,  so 
as  to  heat  the  water  by  circulation.  The  temperature  of  the  oil 
is  observed  by  means  of  a  thermometer  placed  therein  (usually 
this  registers  about  6°  F.  below  the  temperature  of  the  water  in 
the  jacket);  when  the  required  temperature  is  reached,  the 
central  valve  is  raised,  and  50  c.c.  of  oil  allowed  to  run  out  into 
a  measuring  flask  underneath,  the  time  of  efflux  being  noted. 
Obviously,  with  this  instrument,  the  head  under  which  the 
liquid  issues  is  continually  diminishing  as  it  flows. 

Standards  of  Efflux  Viscosity. — In  actual  practice,  water  is 
too  fluid  to  be  a  convenient  standard  substance ;.  rape  oil  is 
usually  chosen  in  preference,  because,  notwithstanding  the  un- 
avoidable differences  that  exist  between  samples  from  seeds 
grown  in  different  countries  and  soils,  these  differences  are 
usually  not  extremely  wide.  Definite  mixtures  of  pure  glycerol 
and  water,  however,  can  be  readily  prepared,  possessing  almost 
any  required  higher  degree  of  "  viscosity,"  §  and  capable  of  use 
as  standards  of  comparison  of  considerably  greater  uniformity, 
when  prepared  by  different  operators  at  different  times,  than  is 
possible  with  natural  products  such  as  rape  oil. 

The  following  tables  are  selected  from  the  numerous  results 
published  by  various  authorities,  as  illustrating  the  general 
character  of  the  numbers  obtained  with  "  viscosimeters "  of 
different  kinds  for  determining  the  relative  efflux  rates  of 
different  natural  oils,  &c.,  and  lubricants  made  therefrom,  or 
from  petroleum  and  other  hydrocarbons,  and  the  effect  of  varia- 
tions of  temperature  011  the  values.  The  figures  obtained  by 

*  Journ.  Soc.  Chem.  Industry,  1890,  p.  654;  from  Dinyler's  polyt.  Journ., 
276,  p.  42. 

t  A  still  more  recent  form  is  described  by  Engler,  with  special  in- 
structions for  its  use  (Journ.  Soc.  C/icm.  Ind.,  1893,  p.  291  ;  from  Zeits. 
ang.  Chem.,  1892,  p.  725). 

$  Journ.  Soc.  Chem.  Industry,  1892,  p.  418. 

§  With  the  viscosimeter  above  described,  Boverton  Redwood  finds  that 
the  relative  times  requisite  for  50  c.c.  of  water  and  genuine  rape  oil  to  flow 
out  at  the  temperature  of  150'5  C.  (60°  F.)  are  25'5  and  535  seconds 
respectively,  taking  the  average  of  various  samples  of  pure  oil.  A.  H.  Allen 
rinds  that  glycerol  diluted  with  water  until  the  specific  gravity  at  15 '5  is 
1'226,  possesses  the  same  degree  of  viscosity  as  average  rape  oil  when 
tested  in  the  same  way. 


102 


OILS,    FATS,    WAXES,    ETC. 


Schiibler  represent  the  "  viscosity  degree "  (viscositdtsgrad)  or 
"  relative  viscosity "  of  the  respective  oils — i.e.,  the  relative 
times  requisite  for  equal  volumes  to  pass  (at  70<5  and  15°  C. 
respectively),  the  times  required  by  the  same  volume  of  water- 
being  taken  as  unity  ;  those  quoted  from  the  other  authorities 
are  not  thus  reduced,  but  are  simply  the  actual  times  directly 
observed  with  the  particular  instruments  used  :  — 


^  ;iine  of  Oil. 

Relative  Time  in  Seconds  (Schiibler). 

Plant  from  which  derived. 

At~c'5C. 

At  15°-0  C. 

Castor  oil, 

liicinus  communis, 

377-0 

203-0 

Olive  oil, 

Olea  europaea,                                31  '5 

21-6 

Hazelnut  oil 

Corylus  avellana.                          24*2 

18-4 

Colza  oil, 

Brassica  campestris  oleifera, 

22-4 

18-0 

Rape  oil, 

Brassica  rapa  oleifera  biennis, 

22-0 

17-6 

Beechnut  oil 

Fagus  sylvatica, 

26-3 

17-5 

White  Mustard  oil, 

Sinapis  alba, 

24-0 

17-4 

Almond  oil,  . 

Amydalus  communis, 

23-3 

16-6 

Spindlenut  oil, 

Kuonymus  europaeus,                   23  '3           15  '9 

Black  mustard  seed  oil, 

Sinapis  nigra, 

19-4 

15-6 

Poppy  seed  oil,     .         .       Papaver  somniferum, 

18-3 

13-6 

Camelina  seed  oil, 

Myagrum  sativum, 

17-7 

13-2 

Belladonna  seed  oil, 

Atropa  belladonna, 

17-3 

13  1 

Sunflower  oil, 

Helianthus  annuus,                      16*4 

12-6 

Turpentine  oil, 

Pinus  sylvestris, 

16-7 

11-8 

Cress  oil, 

Lepidimn  sativum, 

14-4 

11-4 

Grape  seed  oil, 

Vitis  vinifera, 

14-2 

11-0 

Plum  kernel  oil,    . 

Primus  domestica, 

14-7 

10-3 

Tobacco  seed  oil, 

Nicotiaua  tabacum, 

13-5 

10-0 

Walnut  oil,  . 

Juglans  regia, 

11-8 

9-7 

Linseed  oil,  . 

Linum  usitatissimum, 

11-5 

9-7 

Hemp  seed  oil, 

Cannabis  sativa, 

11-9 

9-6 

Relative  Time  in  Seconds  (Wilson). 

Oils,  &.C.,  Used. 

At  15«"6  C. 

At  49°  C. 

At  82°  C. 

=  eo°  F. 

=  120C  l'\ 

=  I80°F. 

Sperm  oil,        .... 

47 

30-5 

25-75 

92 

37'75              28-25 

Lard  oil,          ....                9(j 

38 

28-5 

Rape  oil  
Neat's  foot  oil, 

108 
112 

41-25 
40-25 

30 

29-25 

Tallow  oil,       .... 

143 

37 

25 

Engine  tallow, 

Solid. 

41 

26-5 

YISCOSIMETKY. 
VISCOSITY  IN  SECONDS  FOR  50cc. 


10; 


~te 

II 


» 

t  _ 


S  *  I 


104 


OILS,    FATS,    WAXES,    ETC. 


Rifintd  Rape  Oil 

Sperm  Oil 

American  Miueitil  Oil,  sp.  gr.  -885  . 
,.       '913 
•923  . 

Kiuritm ,       -009  . 

.       -915  . 


.IM    no    too    too    goo   aio    zso 


230     290     300      itc 


1  Fig.  24. — Temperature  in  Degrees  Fahrenheit. 


Oils  Employed. 


,  Sperm  oil, 

Seal  oil  (pale), 
,  Northern  whale  oil, 

Menhaden  oil, 

Sesame  oil, 
1  Arachis  oil, 

Cotton  seed  oil  (refined), 

Niger  seed  oil, 

Olive  oil, 

Rape  oil, 

Castor  oil, 


Relative  Time  in  Seconds  (Allen). 

Spec.  Grav. 
at  150>5C. 

•881 

At  ln°T.C. 
=  60°  F. 

At  r>o°  C. 

=  122«  F. 

At  100°  C. 
-  21'-'°  F. 

so 

I 

47 

38 

•924 

131 

56 

43 

•931 

186 

65 

46 

•932 

172 

40 

•921 

168 

65 

50 

•922 

180 

64 

... 

•925 

180 

62 

40 

•927 

176 

59 

43 

•916 

187 

62 

43 

•915 

261 

80 

45 

•965 

2420 

330 

60 

I 

VISCOSIMETRY. 


105 


Relative  Time  in  Seconds  (Redwood). 

50°  F. 

70°  F. 

100°  F. 

140'  F. 

200SF. 

260°  F. 

300°  F. 

Refined  rape  oil,  No.  1, 

712-5 

405 

147 

105-5 

58-5 

4325 

2 

... 

406 

146 

106-5 

57-5 

... 

"       ,"  £ 

... 

405-5 

147 

106-5 

57-5 

... 

»     4, 

... 

407 

147-5 

106 

58-5 

... 

Beef  tallow, 

54-75 

40 

Sperm  oil, 

... 

136-8 

60-5 

50-75 

42 

34-75 

30 

Neat's  foot  oil,   . 

620 

366 

126 

88-4 

50-4 

44 

38 

American  mineral  oil,  | 
specific  gravity,  '885  j 

145 

90 

47 

41 

,,. 

American  mineral  oil,  1 
specific  gravity,  '923  \ 
Russian  mineral  oil,      \ 

1,030 
2,040 

485 
820 

126 
174 

82 
116 

42 

48-5 

... 

specific  gravity,  '909  J 

Russian  mineral  oil,     } 
semisolid,         .         .  J 

... 

...       531 

317-5 

99-25 

5925 

42  -G 

Redwood's    results   are  indicated    graphically  by  the   curves 
indicated  in  Figs.  23  and  24. 


Castor  oil, 
Thickened  rape  oil, 
Sperm  oil, 
Colza  oil, 
Whale  oil,       . 
Tallow  oil,       . 
Cotton  oil, 
American  885  oil,    . 
American  905  oil,    . 
American  915  oil,   . 
Scotch  865  oil, 
Scotch  885  oil, 
Scotch  890  oil, 
Russian  906  oil, 
Russian  911  oil, 
Rosin  oil,  dark, 
Rosin  oil,  pale, 
Cylinder  oil,  medium, 
Cylinder  oil,  pale, 
Cylinder  oil,  dark, 


Relative  Time  in  Seconds  (Hurst). 

70°  F. 

100°  F. 

120°  F. 

150°  F. 

180°  F. 

1,248 

487-5 

201-5 

91 

48 

1,370 

331-5 

279-5 

156 

78-5 

58-5 

36-4 

26 

19-5 

17 

131 

56, 

44 

325 

28 

128-7 

61 

44 

28-5 

28 

105 

63, 

45 

30 

20 

100 

55 

40 

25 

20 

68 

3-> 

23 

15 

14 

113 

44 

32-5 

19-5 

18 

140 

47 

36 

21 

19-5 

325 

22 

18 

15-5 

13 

58-5 

26 

22             18 

15-5 

71-5 

39 

26 

195 

17 

292-5 

97-5 

56 

30 

22 

462 

143 

91 

82-5 

26 

1525 

97-5 

38 

22 

18 

136-5 

49-4 

25 

18 

17 

385 

255 

170 

70 

... 

405 

265 

120 

90 

... 

890 

495 

230 

100 

As  further  illustration  of  the  effect  of  rise  of  temperature  in 
diminishing  the  rate  of  efflux,  the  following  figures  may  also  be 


106 


OILS,    FATS,    WAXES,    ETC. 


quoted,  obtained  by  Villavecchia  and  Fabris,  whilst  investigating 
certain  lubricating  oils*  for  excise  purposes: — 


Lubricating  oil. 

No.  1 

n 

3 

4 

5 

6 

7 

Efflux  Rate  referred  to  Water  at 


At  20°  C. 

At  50°  C. 

44-39 

6-81 

51-07 

5-94 

40-85 

5-50 

38-77 

6-03 

72-09 

8-35 

67-92 

9-6(5 

56-03 

5-71 

Thus,  the  effect  of  a  rise  in  temperature  from  20°  to  50°  is  to 
diminish  the  efflux  rate  to  -J-  -  -^  of  the  original  value,  the  effect 
being  more  marked  with  the  more  viscous  fluids. 

According  to  experiments  by  Bender,  f  when  an  oil  is  chilled 
to  -  20°  for  some  time,  and  then  warmed  up  again,  the  efflux 
viscosity  value  at  the  ordinary  temperature  is  often  considerably 
increased  as  compared  with  what  it  was  previously  at  the  same 
temperature  of  observation,  thick  oils  usually  showing  a  greater 
increment  than  thinner  ones.  On  the  other  hand,  if  oils  are 
heated  up  to  50°  or  100°,  and  then  allowed  to  cool  down  again 
to  the  air  temperature,  the  thicker  oils  become  perceptibly 
thinner,  whilst  the  thinner  oils  are  less  affected. 

Lepenau's  Leptometer. — This  instrument  is  based  on  a 
principle  somewhat  different  from  that  involved  in  the  above 
^described  forms  of  efflux  viscosimeter,  inasmuch  as  it  depends  not 
only  on  the  rate  of  flow  through  a  given  orifice,  but  also  on  the 
.amount  of  surface  tension  called  into  play  when  drops  are  formed 
in  air.  It  consists  essentially  of  a  pair  of  precisely  similar 
•cylinders,  B  B  (Fig.  25),  immersed  in  the  same  bath,  A,  one  of 
which  contains  the  oil  to  be  examined,  and  the  other  another  oil 
used  as  standard  of  comparison ;  the  relative  rates  are  noted  at 
which  drops  form  as  the  oil  passes  through  equal  sized  capillary 
tubes,  r,  r,  the  dimensions  of  which  are  too  small  to  permit  of 
continuous  streams  being  produced,  the  quantities  flowing  out  in 
a  given  time  being  weighed  or  measured. 

All  these  various  forms  of  instrument  are  subject  to  one 
constant  source  of  error — viz.,  that  the  forces  coming  into  play 

*  "  Report  of  the  Central  Laboratory  of  the  Italian  Customs'  Depart- 
ment, 1891 ;  also  Journ  Soc.  Chem.  Industry,  1891,  p.  390. 

t  Journ.  Soc.  Chem.  Industry,  1891,  p.  936;  from  Mitth.  Konig.  techn. 
Versuchs,,  Berlin,  1891,  p.  100.' 


VISCOSIMETRY. 


107 


when  a  viscous  liquid  passes  through  a  tube  or  orifice  under 
given  conditions  of  temperature,  &c.,  are  not  the  same  as  those 
obtaining  when  the  liquid  is  used  as  a  lubricant  for  shafting, 
quickly  rotating  spindles,  axles,  and  the  like ;  and,  consequently, 
that  the  figures  obtained  by  means  of  such  testing  appliances  are 
only  approximations  (and  not  always 
close  ones)  to  the  relative  values 
of  the  substances  examined,  when 
practically  applied  for  lubricating 
purposes. 

Determination  of  Viscosity  in 
Absolute  Measure.-When  liquids 
are  examined  possessing  a  compara- 
tively low  degree  of  viscous  charac- 
ter, the  rate  of  flow  through  a  narrow 
orifice  does  not  represent  the  true 
physical  "viscosity,"  because  a  large 
proportion  of  the  result  is  due  to 
flow  pure  and  simple  without  any 
"  shear  ;  "  accordingly,  when  a  com- 
paratively long  narrow  accurately 
calibrated  tube  is  made  use  of  as 
the  jet,  figures  are  obtained  not 
always  showing  close  agreement 
with  those  yielded  by  the  ordinary 
forms  of  efflux  apparatus.  Accord- 


Fig.  25. 


ing  to  mathematical  investigations  by  Poiseuille  and  others,  the 
coefficient  of  friction  in  narrow  tubes  is  given  by  the  formula 


where  75  is  the  coefficient  of  friction,  t"  the  time  of  efflux,  v  the 
volume  of  fluid  discharged,  p  the  hydraulic  pressure,  I  the  length 
and  r  the  radius  of  the  capillary  tube,  and  s  the  specific  gravity 
of  the  liquid.*  Starting  from  this,  E.  J.  Mills  has  made  some 
measurements  in  absolute  measure  of  the  coefficients  of  friction 
for  various  liquids,  including  water,  and  sperm,  olive,  lard,  and 
-castor  oils.f 

On  the  C.G.S.  system  (centimetre,  gramme,  and  second  as  units 
of  length,  mass,  and  time  respectively)  Poiseuille's  formula  becomes 


*  Hagenbacli  arrives  at  a  formula  involving  a  second  term  in  addition  to 
that  given  by  Poiseuille  — 


t  Joiirn.  Soc.  Chem.  Ind.,  188C,  p.  148;  also,  1887,  p.  414. 


108 


OILS,    FATS,    WAXES,    ETC. 


where  v  is  given  in  cubic  millimetres,  and  r,  I,  and  p  in  milli- 
metres ;  from  this  formula  and  his  experimental  results,  Mills 
deduces  the  following  values  at  12°  0. : — 


Specific  Gravity. 

Value  of  »j. 

Rehitive  Viscosity, 
Water  =1. 

Water, 

1  -000 

•011713 

i-oo 

Sperm  oil,   . 

•88789 

•68828                   5876 

Olive  oil, 

•1)2043                1-1393                     97-27 

Lard  oil, 

•92051                 1-6285                    139  '03 

Castor  oil,    .         .         .               -915541 

21-721 

1854-4 

Obviously  these  relative  viscosity  values  are  very  dissimilar 
from  Schiibler's  numbers  for  castor  and  olive  oils  compared  with 
water,  although  the  ratios  between  the  values  for  the  oils  alone 
do  not  differ  so  widely  in  the  two  cases ;  this  chiefly  arisen 


Fig.  20. 

from  the  error  attaching  to  the  viscosity  determination  in  the 
case  of  water  by  the  efflux  method  through  a  jet,  as  compared 
with  the  true  value  through  a  long  narrow  tube.* 

*  The  determinations  of  absolute  "  viscosity  "  values  of  solutions  of  gum 
relatively  to  water  made  by  noting  the  times  required  for  given  volumes  to 
pass  through  a  known  capillary  tube,  show  similar  differences  when  compared 
with  the  corresponding  values  obtained  with  a  "jet"  apparatus,  such  as  a 
burette  (vide  paper  by  S.  Rideal,  Journ.  Soc.  Chem.  Ltd.,  1891,  p.  610). 


VISCOS1MKTRY. 


109 


Coefficient  of  Friction  in  Capillary  Tubes. — Traube  has 
constructed  an  arrangement  for  determining  with  considerable 
accuracy  and  speed  the  friction  coefficients  for  oils  and  other 
liquids  passing  through  capillary  tubes  under  pressure.  Fig.  26 
represents  this  apparatus.*  A  is  a  Marriotte  bottle  filled  with 
water,  which  serves  to  compress  air  in  the  reservoir  B,  and  to 
keep  the  pressure  constant ;  B  is  connected  by  means  of  a  pipe 
and  cock  to  the  efflux  apparatus  H,  consisting  of  the  bulb  G- 
(provided  with  two  marks  to  permit  the  measurement  of  volume 
of  liquid  to  be  discharged)  and  the  capillary  tube  E.  The 
reservoir  B  is  filled  by  means  of  a  pump  attached  to  branch  and 
stopcock.  When  the  observations  are  to  be  made  at  temperatures 
above  that  of  the  atmosphere  a  suitable  airbath  is  employed. 
When  required  to  be  cleaned,  ether  is  forced  through  the  tube. 
With  tubes  of  different  diameters,  the  relative  times  observed  for 
water  and  oils  of  high  viscosities  are  not  identical ;  but  for  oils 
of  considerable  viscosity  the  differences  are  not  great ;  thus,  the 
following  figures  were  observed  with  a  cylinder  lubricating  oil 
and  with  olive  oil  as  compared  with  rape  seed  oil,  being  the 
respective  times  of  efflux  in  seconds  : — 


Diameter  of  tube  in  milli-  \ 
metres,          .         .         .  J 

1-5 

0-8 

0-5 

Cylinder  oil,     . 

155  -5  -100-0 

472=100-0 

2960=1000 

Rape  seed  oil,  . 

79-0=  50-8 

242-  51-3 

1503=  50-8 

Olive  oil,  .... 

717-  46-1 

222=   47-0 

1364=  46-1 

In  all  probability  the  conditions  existing  when  oil  is  forced 
through  a  capillary  tube  are  more  nearly  akin  to  those  obtaining 
with  a  film  of  oil  lying  between  a  shaft  and  its  journal  box  than 
are  those  subsisting  in  the  ordinary  forms  of  efflux  viscosimeter ; 
and  hence  it  is  probable  that  the  results  of  valuations  on 
Traube's  system  would  be  valuable  as  determinations  more 
closely  approximating  to  the  actual  practical  lubricative  values. 
Traube  s  apparatus,  however,  is  far  less  convenient  for  ordinary 
laboratory  work  than  Redwood's  or  Engler's  viscosimeter. 

*  Journ.  Soc.  Chem.  Ind.,  1887,  p.  414. 


110  OILS,    FATS,    WAXES,    ETC. 


§  3.  Chemical  Properties  of  Oils,  Fats, 
Butters,  and  Waxes. 


CHAPTER  VI. 

PROXIMATE  CONSTITUENTS  AND  THE  METHODS  USED 
FOR  THEIR  EXAMINATION  AND  DETERMINATION. 

VERY  few,  if  any,  natural  oils,  fats,  and  waxes  consist  of  one 
single  chemical  substance ;  almost  invariably  two,  and  often 
many  more  constituents  are  present,  the  most  marked  distinc- 
tion between  which  is  that  some  are  solid  at  the  ordinary  tem- 
perature (when  obtained  separate),  others  liquid;  the  former 
often  deposit  in  the  solid  form  on  chilling,  so  that  a  fluid  oily 
when  chilled  and  pressed,  yields  a  solid  so-called  "  stearine"  and 
a  liquid  so-called  "  oleine  "  *  as  first  proximate  constituents.  In. 
similar  fashion  semisolid  butters  and  hard  fats,  like  tallow,  can 
be  showrn  to  contain  a  solid  and  a  liquid  constituent  in  each  case, 
the  consistency  of  the  material,  roughly  speaking,  depending 
simply  on  the  relative  proportions  of  the  two  substances.  When 
"oleine"  largely  predominates  the  substance  is  an  oil;  when 
'*  stearine,"  a  hard  fat ;  and  when  the  two  are  in  intermediate 

*  The  terms  "stearine"  and  "oleine"  are  practically  employed  in 
several  different  senses,  a  circumstance  apt  to  lead  to  considerable  con- 
fusion. In  the  strict  chemical  sense,  stearine  is  the  glyceride  of  stearic  acid, 
C8Hfi(O.Ci8H35O)8j  and  oleine  the  glyceride  of  oleic  acid,  CaHsCO.CjaHssOJa  , 
but  in  the  oil  trade  generally  the  two  terms  are  applied  to  indicate  respec- 
tively the  solid  and  liquid  constituents  into  which  a  fat  or  chilled  oil  can 
be  mechanically  separated,  irrespective  of  the  actual  chemical  composition 
of  these  constituents  ;  whilst  in  the  candle  manufacture  they  are  used  to 
denote  the  analogous  solid  and  liquid  fatty  acids  obtainable  from  fatty 
matters  by  saponification  and  mechanical  pressure,  &c.  Similar  mixtures  of 
free  fatty  acids  and  other  substances  are  also  obtainable  by  subjecting  to 
distillation  various  kinds  of  grease  (e.g.,  Yorkshire  grease  — Chap,  xn.)  ; 
when  these  are  chilled  aud  pressed  they  are  separable  into  solid  and 
liquid  portions,  generally  designated  as  "distilled"  stearine  and  oleine 
respectively.  In  the  present  work  the  pure  chemical  triglycerides  are  dis- 
tinguished by  the  terminal  "in"  (e.g.,  stearin,  olein,  &c.)  ;  whilst  the 
commercial  articles  are  indicated  by  names  ending  in  "ine"  (e.g.,  "  dis- 
tilled "  oleine,  candlemakers'  stearine,  oleomargarine,  &c. ).  In  similar 
fashion,  the  pure  chemical  compound  C3Hr,(OH)3  is  referred  to  as- 
"  glycerol,"  whilst  the  commercial  products  mainly  consisting  of  this  body, 
but  in  a  varying  state  of  purity,  are  distinguished  as  glycerine  (vide  p.  8). 


PROXIMATE    CONSTITUENTS.  Ill 

proportions,  a  more  or  less  buttery  consistence  is  possessed  at  the 
ordinary  temperature  (near  15°  C.) 

The  further  investigation  of  the  solid  and  liquid  constituents 
thus  obtainable  from  a  given  oil  or  fat ;  of  the  variations  in  their 
relative  proportions  and  natures  according  to  the  soil  and  climate 
and  other  conditions  under  which  the  plant  was  grown  in  the 
case  of  vegetable  oils  or  butter,  or  the  species  and  habitat  of  the 
animal  in  that  of  an  animal  oil  or  fat ;  of  the  eifect  of  cultivation 
and  domestication,  and  various  similar  points,  have  hitherto 
received  but  little  attention.  There  appears,  however,  to  be 
some  reason  for  supposing  that  very  considerable  differences  in 
the  relative  amounts  and  even  in  the  chemical  nature  of  the 
various  constituents  of  a  given  oil,  &c.,  may,  at  any  rate  in  some 
cases,  be  brought  about  by  such  causes ;  thus,  very  different 
results  have  been  found  by  various  experimenters  who  have 
examined  different  samples  of  the  same  kind  of  oil — e.g.,  in 
the  case  of  arachis  oil  (groundnut  oil),  where  several  succes- 
sive chemists  have  succeeded  in  isolating  considerable  amounts 
of  hypogceAc  acid  for  the  purpose  of  studying  that  substance 
and  its  derivatives,  whilst  more  than  one  other  chemist  has 
found  either  none  at  all,  or  practically  none,  in  the  oil  ex- 
amined by  him ;  and  where,  moreover,  some  observers  have 
found  more  or  less  considerable  amounts  of  palmitic  acid,  and 
others  none  at  all.  Similar  discrepancies  in  the  results  obtained 
by  different  investigators  have  been  noticed  in  several  other 
instances,  thus  leading  to  the  conclusion  that  marked  differences, 
are  apt  to  exist  in  the  nature  of  oils  and  fats  prepared  from 
seeds,  &c.,  grown  under  different  conditions,  just  as  is  well 
known  to  be  the  case  with  fruits  and  other  vegetable  produce,  as- 
regards  the  saccharine  matter  and  other  constituents  present 
therein.  Even  without  taking  into  account  these  natural  varia- 
tions, however,  the  knowledge  at  present  extant  of  the  proximate 
constituents  of  many  of  the  more  commonly  occurring  oily  and 
fatty  matters  is  decidedly  scanty ;  whilst  a  very  large  number  of 
similar  substances  exist  (in  many  cases  of  great  local  importance, 
although  not  always  materials  largely  exported  or  imported  or 
otherwise  dealt  with  commercially)  concerning  the  general  com- 
position of  which  accurate  knowledge  is  hitherto  entirely  want- 
ing. Many  such  products  promise  in  the  near  future  to  be 
important  articles  of  trade,  as  soon  as  their  respective  values  for 
particular  purposes  are  better  ascertained,  and  the  best  means, 
to  be  adopted  of  extracting  and  refining  them  so  as  to  render 
them  marketable  ;  in  Central  and  Southern  Africa,  and  in  many 
other  parts  of  the  world,  the  progress  of  civilisation  is  continually 
tending  to  bring  into  notice  new  products  of  this  kind,  many  of 
which  only  require  attention  being  called  to  them  to  demonstrate 
their  commercial  value. 

The  separation  from  one  another  of  the  different  glycerides, 


112  OILS,    FATS,    WAXES,    ETC. 

<fec.,  contained  in  a  given  "  stearine "  or  "  oleine "  is,  in  most 
cases,  a  very  difficult  problem,  more  especially  if  required  to  be 
performed  in  such  a  fashion  as  to  give  an  approximate  idea  of  the 
relative  proportions  in  which  they  are  present.  As  a  rule,  the 
best  results  are  obtained  by  saponifying  the  mixture,  and 
applying  methods  for  the  separation  of  the  resulting  fatty  acids, 
•either  by  mechanical  means  (chilling  and  pressing  out  the 
more  liquid  portions)  or  by  chemical  processes.  For  example, 
the  lead  salt  of  oleic  acid  is  soluble  in  ether,  whilst  lead  stearate, 
palmitate,  &c.,  are  practically  insoluble  in  that  medium  ;  so  that 
l)y  converting  into  lead  salts  the  mixture  of  free  fatty  acids 
obtained  on  saporiification  and  acidulation,  and  treating  the  mix- 
ture with  ether,  a  partial  separation  may  be  effected,  lead  oleate 
with  comparatively  small  quantities  of  stearate,  palmitate,  &c., 
being  dissolved  out,  and  lead  stearate,  palmitate,  etc.,  with  small 
quantities  of  adhering  oleate  being  left.  With  a  mixture  of  solid 
iatty  acids  (palmitic,  stearic,  arachic,  tkc.),  fractional  crystallisa- 
tion from  alcohol  of  the  mixed  free  acids ;  fractional  precipitation 
.as  insoluble  salts  (of  lead,  magnesium,  &c.);  fractional  crystal- 
lisation of  certain  salts  (e.g.,  magnesium  salt)  from  alcohol  or  other 
•appropriate  menstruum ;  and  similar  processes  are  applicable  in 
various  cases  ;  but  the  complete  examination  of  mixtures  of  fatty 
iicids  in  this  way  is  so  laborious,  that  it  has  been  thoroughly 
carried  out  in  but  very  few  instances.  In  the  case  of  fractional 
precipitation,  as  a  general  rule,  the  acid  of  higher  molecular 
weight  precipitates  first;  thus,  with  a  mixture  of  arachic,  stearic, 
und  palmitic  acids  in  approximately  equal  proportions,  precipi- 
tated as  salts  in  several  fractions,  the  first  fraction  will  be 
chiefly  a  salt  of  arachic  acid,  and  the  last  will  contain  little 
besides  palmitate. 

Some  oils  and  fats  contain  appreciable  quantities  of  the 
glycerides  of  acids  of  sufficiently  low  molecular  weight  to  be 
volatile  along  with  the  vapour  of  water  at  the  ordinary  atmo- 
spheric pressure.  In  such  a  case,  after  sapoiiification  and  acidula- 
tion, an  acid  distillate  is  obtainable  by  boiling,  preferably  by 
Mowing  through  the  mass  a  current  of  steam  from  a  suitable 
generator.  The  weakly  acid  aqueous  fluid  may  then  be  neutralised 
with  an  alkali,  evaporated  to  a  small  bulk,  and  decomposed  by  a 
mineral  acid ;  or  converted  into  silver  or  barium  salts,  &c.,  and 
further  examined.  If  more  than  one  volatile  acid  be  present,  a 
separation  may  often  be  effected  by  fractional  precipitation  as 
silver  salt,  &c. ;  or  enough  mineral  acid  may  be  added  to  liberate 
a  fraction  of  the  total  organic  acids  from  the  evaporated  solution 
of  alkaline  salts,  and  the  distillation  repeated  ;  the  acid  of  lowest 
molecular  weight  will  then  pass  over.  By  similarly  liberating 
successive  fractions  and  distilling  alternately,  a  series  of  distillates 
will  be  obtained,  the  acids  of  higher  molecular  weight  being 
•contained  in  the  respective  later  fractions  (Liebig). 


PROXIMATE   CONSTITUENTS.  113 

When  a  mixture  of  acids  volatile  with  steam  and  others  not 
volatile  therewith  is  present,  if,  instead  of  blowing  steam  through 
the  whole  mass,  the  insoluble  fatty  acids  be  allowed  to  float  up 
in  a  fused  condition,  and  are  then  removed  (after  cooling  and 
solidifying),  the  remaining  aqueous  liquor  is  often  found  to 
yield  perceptibly  less  volatile  acid,  a  portion  having  been  dis- 
solved by  the  insoluble  acids,  much  as  ether  dissolves  out  various 
substances  from  aqueous  solution  when  agitated  therewith.  In 
consequence  of  this,  it  is  often  impossible  to  obtain  a  constant 
weight  of  the  insoluble  fatty  acids  thus  obtained  on  drying  at 
100°,  unless  they  have  been  repeatedly  treated  with  boiling  water, 
so  as  to  remove  soluble  constituents  (vide  Chap.  VIIL,  "  Hehner 
Number");  otherwise,  the  small  quantity  of  volatile  acid  present 
slowly  evaporates,  giving  a  continual  small  loss.  In  some  cases, 
this  by  and  by  becomes  balanced  by  gain  in  weight  through 
oxidation  (by  spontaneous  absorption  of  oxygen  from  the  air), 
and  later  011  still  the  gain  from  this  cause  predominates. 

By  means  of  superheated  steam  the  fatty  acids  of  higher 
molecular  weight  may  be  pretty  readily  distilled;  but  any- 
thing like  a  complete  separation  of  closely  related  homologous 
acids  (e.g.,  myristic,  palmitic,  and  stearic  acids)  in  this  way  by 
processes  of  fractional  distillation  is  difficult,  if  not  impossible ; 
and  the  same  remark  applies  to  distillation  under  greatly  dimin- 
ished pressure  (in  a  partial  vacuum).  In  some  cases  fractional 
saturation  with  alkali,  £c.,  of  a  mixture  of  acids  will  cause  a  more 
or  less  complete  separation,  one  combining  with  the  base  to  the 
exclusion  of  the  other:  more  often  the  base  becomes  shared  between 
the  two  in  proportions  depending  on  the  relative  masses  present. 
Thus  Thum  found  *  that  when  a  mixture  of  equal  weights  of 
stearic  and  oleic  acids  is  dissolved  in  hot  alcohol  and  treated 
with  a  quantity  of  alcoholic  potash  sufficient  to  saturate  only 
one  half  of  the  total  acids,  a  mixed  soap  is  obtained,  which  (when 
separated  from  the  uncombined  excess  of  fatty  acids  by  means  of 
petroleum  ether)  consists  substantially  of  equal  quantities  of 
potassium  stearate  and  oleate  ;  the  free  acids  similarly  consisting 
of  stearic  and  oleic  acids  in  sensibly  the  same  proportion.! 

A  good  deal  still  remains  to  be  done  in  the  case  of  a  consid- 
erable number  of  vegetable  oils  in  the  way  of  identifying  and 
quantitatively  estimating  their  various  proximate  constituents; 
and  much  the  same  remarks  apply  to  certain  animal  oils,  more 
especially  "  train  oils  "  from  marine  cetaceans,  as  regards  not 
only  the  acids  present  but  also  the  alcoholiform  constituents  ; 

*Zeit*ch.f.  ancjeic.  Chemie,  1890,  p.  482. 

t  A  similar  state  of  matters  is  observed  when  a  given  fatty  acid  acts  on 
a  mixture  of  caustic  potash  and  caustic  soda  ;  both  potash  and  soda  soaps 
result  in  proportions  sensibly  near  to  those  in  which  the  two  alkalies  are 
present  in  the  mixture  ;  and  not  one  kind  of  soap  to  the  exclusion  of  the 
other  (vide  Chap,  xxi.) 

8 


114  OILS,    FATS,    WAXES,    ETC. 

whilst  it  is  known  that  certain  of  these  oils  are  mainly  composed 
of  compound  ethers  of  non-glyceridic  character,  which  furnish  on 
saponincation  acids  mostly  of  the  oleic  family,  and  as  comple- 
mentary products,  alcohols  of  moderately  high  molecular  weight 
(e.g.,  dodecatylic  alcohol,  C12H26O,  from  Doegling  oil),  the  complete 
investigation  of  the  products  thus  formed  has  been  attempted 
in  very  few  instances  indeed,  and  much  still  remains  to  be  done 
in  this  field  ;  it  appears,  however,  that  besides  alcohols  of  the 
ethylic  series,  others  of  a  non-saturated  character  are  also  present 
in  some  of  these  oils,  as  the  alcoholiform  constituents  extracted 
are  in  many  cases  capable  of  combining  with  iodine,  leading  to 
the  conclusion  that  higher  acrylic  alcohols  are  also  contained  as 
compound  ethers  in  addition  to  cetylic  alcohol  homologues. 

Free  Fatty  Acids  and  Higher  Alcohols  contained  in 
Natural  Oils  and  Fats,  &c. — Owing  to  the  presence  of  mucila- 
ginous, albuminous,  or  gelatinous  matters  in  most  crude  vegetable 
oils  expressed  from  seeds,  or  animal  fats  and  oils  obtained  from 
animal  tissues,  it  generally  happens  that  a  perceptible  amount 
of  hydrolysis  of  glycerides  is  brought  about  in  the  process  of 
extraction,  due  to  the  influence  of  these  substances  and  the 
fermentative  changes  rapidly  undergone  by  them ;  even  when 
solvents  (such  as  light  petroleum  oil,  carbon  disulphide,  or  ether) 
are  used  for  the  isolation  of  the  oil,  &c.,  it  not  unfrequently 
happens  that  measurable  amounts  of  free  fatty  acids  are  con- 
tained in  the  product  obtained  ;  leading  to  the  conclusion  that 
hydrolytic  actions  naturally  take  place  to  a  greater  or  lesser 
extent  in  the  seeds,  tissues,  &c.,  during  crushing  and  analogous 
operations,  or  even  on  simply  keeping,  so  that  small  quantities 
of  free  acids  are  practically  always  present  in  the  natural 
products  as  obtained  on  a  manufacturing  scale  from  the  animal 
after  death,  or  from  the  seed  after  detaching  from  the  plant, 
even  when  not  normally  present  in  the  living  animal  or 
growing  vegetable.  The  extent  to  which  actions  of  this  sort 
take  place  is  extremely  variable ;  in  general  the  "  cold  drawn " 
oils  expressed  from  seeds,  and  the  corresponding  first  runnings, 
from  fresh  fish  livers,  and  the  more  liquid  "oleomargarine," 
obtained  by  the  action  of  gentle  heat  on  animal  fats,  contain 
much  smaller  proportions  of  free  fatty  acids  than  the  later 
fractions  obtained  by  subsequent  hot  pressing  and  analogous 
operations  ;  whilst  in  the  case  of  vegetable  oils  the  maximum 
amounts  of  free  fatty  acids  are  contained  in  the  oils  extracted 
by  solvents  from  oilcakes,  and  in  those  obtained  from  vegetable 
pulps  (pounded  nuts,  crushed  olives,  and  such  like)  by  heating 
with  water  so  that  oily  matter  floats  up,  separated  by  skimming — 
i.e.,  in  those  cases  where  contact  with  fermentible  matters  has 
been  most  intimate  and  prolonged.  Thus,  the  following  figures 
were  obtained  by  Noerdlinger,*  the  total  fatty  matter  being 
*  Journ.  Soc.  Cfiem.  Ind.,  1890,  p.  422,  from  Zeit*.  Anal  Chfm.,  29,  p.  6. 


PROXIMATE    CONSTITUENTS. 


115 


extracted  from  the  seeds  by  means  of  light  petroleum  spirit,  and 
the  free  fatty  acid  (determined  by  titration  with  phenolphthalein. 
as  indicator)  reckoned  as  oleic  acid  (vide  p.  117)  : — 


103  Parts 

contain 

Free  Fatty 

Oils. 

Acids  Reckoned 
per  100  of  Total 

Free  Fatty 
Acids. 

Total  Fat. 

Fat. 

Rape  (jBras.nca  rapct), 

0-42 

37'75 

MO 

Cabbage  (B.  c.ampestris),  . 
Poppy  (Papover  somni/eritm)  ,  . 

0-32 
3-20 

41-22 
46-90 

0-77 
6-66 

Earthnut   (Arachis    hypoy<ea)  \ 

seed,                                           / 

1--91 

40-09 

4-15 

Earthnut   (Arackift    hypogcva)  \ 
outside  pale  husk,          .         J 

1-91 

4-43 

43-10 

Sesame  (Sesamum  orientate),     . 

2-21 

51-59 

4-59 

Castor  (Riclnus  communit"), 

1-21 

46-32 

2-52 

Palmnut       (Elais      guinenxis)  } 
containing  6  per  cent,  husks,  J 

4-19 

49-16 

8-53 

Cokernut  (Cocos  nucifera), 

2-98 

67-40 

4-42 

Oil  Cakes. 

Rape,        .                  ... 

093 

8-81 

10-55 

Poppy,      .                  ... 

5-06 

9-63 

58-89 

Earthnut, 

1-42 

7-65 

18-62 

Sesame,     .                  ... 

6-15 

15-44 

40-29 

Palmnut,  .                   ... 

1-47 

10-39 

14-28 

Cokernut, 

1-31 

13-11 

10-51 

Linseed,    .                  ... 

0-75 

8-81 

9-75 

Castor,      .                   ... 

1-27 

653 

2007 

Obviously,  when  oil  contains  any  considerable  quantity  of  free 
fatty  acids  the  use  of  alkaline  refining  processes  (Chap,  xi.)  is  apt 
to  lead  to  a  considerable  diminution  in  the  quantity  of  refined 
product  obtained,  as  compared  with  the  raw  material  employed, 
because  the  free  fatty  acids  are  removed  in  the  form  of  soaps,  the 
production  of  which,  moreover,  often  leads  to  further  loss  by 
the  mechanical  en  tangling  of  "  neutral "  oil  in  .the  saponaceous 
"  foots." 

The  presence  of  free  fatty  acids  in  any  quantity  in  most 
kinds  of  oils  is  detrimental  to  their  value,  more  especially  in 
reference  to  certain  applications.  Thus,  in  the  case  of  lubricating 
oils,  corrosion  of  bearings,  etc.,  is  more  apt  to  be  brought  about 
when  free  fatty  acids  are  present  than  when  the  oil  is  practically 
free  therefrom  ;  and  hence  in  such  cases  alkaline  refining  pro- 
cesses will  often  give  a  superior  result,  the  more  so  that  acid 
processes  are  apt  to  communicate  to  oil  refined  thereby  traces  of 
mineral  acid,  the  corrosive  action  of  which  is  still  more  marked. 
This  is  notably  the  case  with  oils  intended  for  wool  spinning  and 


116  OILS,    FATS,    WAXES,    ETC. 

analogous  purposes.  Colza  oil  containing  much  free  fatty  acids 
burns  less  freely,  and  is  more  apt  to  char  the  wick  than  com- 
paratively neutral  oil.  On  the  other  hand,  the  taste  of  olive  oil 
is  said  to  be  considerably  improved  by  the  presence  therein  of 
small  quantities  of  free  acids ;  whilst  largely  hydrolysed  oils 
(kuiles  tournantes]  are  intentionally  prepared  for  certain  special 
purposes  in  the  textile  and  dyeing  industries. 

In  the  case  of  blubber  oils  largely  consisting  of  the  compound 
ethers  of  higher  monatomic  alcohols  of  the  ethylic  series,  the 
hydrolytic  actions  taking  place  during  storage  before  and  after 
extraction,  and  whilst  the  "rendering"  is  taking  place,  lead  to 
another  result — viz.,  that  cetylic  alcohol  and  analogous  bodies  are 
largely  contained  in  the  oils  ultimately  obtained ;  thus,  from  30 
to  40  per  cent.,  and  sometimes  more,  of  so-called  " unsaponifiable 
matter "  is  frequently  found  to  be  present  in  sperm  and  other 
blubber  oils,  chiefly  consisting  of  alcoholiform  products  of 
hydrolytic  actions  of  this  description.  Similar  remarks  apply 
to  beeswax,  and  to  the  various  vegetable  waxes  of  analogous 
constitution  ;  figures  are  on  record,  obtained  by  various  analysts, 
indicating  in  extreme  cases  that  from  J  to  §  of  the  original 
compound  ethers  have  been  hydrolysed  by  actions  of  this 
description,  either  occurring  naturally  during  storage,  or  in  con- 
sequence of  the  processes  adopted  in  preparing  the  raw  material. 


DETERMINATION    OF    FREE    FATTY    ACIDS. 
FREE    ACID    NUMBER. 

The  most  accurate  process  for  determining  the  amount  of  free 
acids  contained  in  a  given  sample  of  oil  or  fat,  consists  in  agitating 
it  with  warm  alcohol,  and  dropping  in  a  standard  alkaline  solu- 
tion (preferably  alcoholic)  until  a  persistent  pink  coloration 
appears  after  continued  agitation,  phenolphthalein  being  the 
indicator ;  the  temperature  must  be  high  enough  to  render  the 
fat  perfectly  fluid.  Or  the  oil  may  be  dissolved  in  cold  ether, 
mixed  with  a  little  alcohol,  and  the  solution  titrated  with 
standard  alcoholic  alkali.  If  the  mean  equivalent  weight  of 
the  free  fatty  acids  is  known  (or  assumed)  to  be  E,  the  pro- 
portion of  fatty  acids  in  the  free  state  is  given  by  the  formula, 

x  =  JLX^  x  100, 
w 

where  w  is  the  weight  in  milligrammes  of  material  taken  for 
examination,  n  the  number  of  c.c.  of  normal  alkali  used,*  and 
x  the  weight  of  free  fatty  acids  contained  in  100  parts  of  sub- 
stance (percentage  of  free  fatty  acids)  ;  for  since  1  c.c.  of  normal 

*  If  seminormal  (or  decinormal)  alkali  be  used,  the  value  of  n  will 
obviously  be  *  (or  Y1^)  of  the  number  of  c.c.  used,  and  so  on. 


DETERMINATION    OF    FREE    ACID    NUMBER.  117 

alkali  represents  E  milligrammes  of  fatty  acids,  the^total  weight 
of  acids   contained  in    w  milligrammes  of  substance   is  n  x   E 

milligrammes,  whence  100  parts  of  substance  contain  -     —  x  100 

parts  of  free  fatty  acids. 

In  many  instances  the  value  of  E  is  not  known  accurately, 
and  in  such  cases  it  is  more  convenient  to  express  the  amount 
of  fatty  acids  in  terms  of  the  alkali  neutralised.  This  may  be 
done  with  respect  to  100  parts  of  original  substance,  thus  giving 
the  percentage  of  potash  (or  soda)  neutralised,  according  to  the 
alkali  employed  ;  but  a  more  usual  practice  is  to  express  the 
value  relatively  to  1,000  parts  of  original  substance,  potash 
(caustic  potash,  KOH,  equivalent  56'1),  being  selected  as  the 
alkali,  thus  giving  the  permillage  of  potash  neutralised,  con- 
veniently referred  to  as  the  "free  acidity  potash  permillage,"  or 
"free  acid  neutral' sation  number,"  or,  more  shortly,  as  the  "  free 

acid  number,"  and  expressed  by  the  value     -  x  56,100.* 

Thus,  suppose  that  10  grammes  (10,000  milligrammes)  of  palm 
butter  neutralise  8  c.c.  of  seminormal  alkali,  equivalent  to 
4'0  c.c.  of  normal  alkali ;  since  1  c.c.  of  normal  alkali  corre- 
sponds with  56-1  milligrammes  of  KOH,  and  with  256  milli- 
grammes of  palmitic  acid  (i.e.,  E  =  256  j,  the  result  may  be  stated 
by  saying  that  the  "  free  acidity  potash  permillage  "or  "  free 

acid  number  "  is  JQ-^K  x  56,100  =  22*44;  or  it  may  be  expressed  in 

terms  of  percentage  of  palmitic  acid  by  saying  that  the  substance 

4*0  x  *^J56 
contains  free  acids  jointly  equivalent  to        _  ooo"    x  ^^  =  l^'-M 

per  cent,  of  palmitic  acid. 

When  only  small  quantities  of  free  acid  are  present,  and 
extremely  sharp  valuations  are  desired,  somewhat  large  quantities 
of  material  should  be  taken  for  the  determination ;  20  or  25 
grammes,  or  even  more.  A  less  accurate  method  of  determining 
free  fatty  acids  consists  in  shaking  up  the  oil,  &c.,  with  alcohol, 
allowing  to  stand,  separating  a  known  fraction  of  the  alcoholic 
fluid,  and  titrating  with  standard  alkali  ;  the  result  is  apt  to  be 
somewhat  too  low  on  account  of  incomplete  solution  of  all  free 
acid  by  the  alcohol. 

In  some  natural  oils  (e.g.,  unrefined  cotton  seed  oil)  substances 
are  present  of  an  acid  character,  although  not  belonging  to  the 

*  Since  1  c.c.  of  normal  alkali  represents  56'1  milligrammes  of  KOH,  n  c.c. 
represent  n  x  56 '1  milligrammes:  then  if  A  be  the  free  acid  number  as 
above  defined, 

w  :  n  x  56'1  :  :  1,000  :  A 

whence  A=  — x  56,100. 


118  OILS,    FATS,    WAXES,    ETC. 

ordinary  fatty  acid  series,  but  more  resembling  the  acids  of  pine 
resin ;  these  substances  neutralise  alkali  (phenolphthalein  being 
the  indicator),  and  are  consequently  included  in  the  total  of  "free 
fatty  acids "  determined  by  titration.  Occasionally  ordinary 
rosin  (colophony)  is  intentionally  added  to  oils  or  the  fatty  acids 
thence  derived,  either  as  an  adulterant  or  for  special  reasons — 
e.g.,  in  the  manufacture  of  some  kinds  of  waggon  grease  and 
"yellow  "  soap.  For  the  methods  used  in  determining  the  amount 
of  resin  present  in  such  cases,  vide  Chap.  xxi. 

When  it  is  required  to  separate  the  free  fatty  acids  from  the 
neutral  fat,  this  is  readily  accomplished  by  adding  alcoholic 
alkali  until  just  neutral  to  phenolphthalein,  diluting  with  water, 
and  agitating  with  ether,  or  better,  with  light  petroleum  spirit.* 
The  ethereal  liquid  on  evaporation  leaves  the  neutral  fatty 
matter,  which  can  be  weighed  and  further  examined  as  desired ; 
the  aqueous  fluid  is  acidulated  and  shaken  with  petroleum  spirit, 
&c.,  whereby  the  free  fatty  acids  are  similarly  obtained. 

If  mucilaginous  matter,  &c.,  is  also  present,  the  oil  may  be 
ground  up  in  a  dish  with  half  its  weight  of  solid  sodium  car- 
bonate and  as  much  water,  and  dried  on  the  waterbath ;  the 
residue  is  again  stirred  up  with  coarsely  powdered  pumice- 
stone,  and  exhausted  with  ether  containing  no  alcohol,  whereby 
the  neutral  fat  is  dissolved  out.  The  residue  is  exhausted  with 
hot  alcohol,  and  the  resulting  soap  solution  evaporated  and 
decomposed  by  a  mineral  acid,  so  as  to  obtain  the  free  fatty 
acids,  originally  present  as  such,  free  from  the  other  constituents. 
Or  the  fat,  &c.,  may  be  treated  with  ether,  carbon  disulphide,  or 
other  solvent ;  by  filtering  through  a  weighed  filter  and  washing 
the  insoluble  matter  thoroughly,  the  mucilage,  &c.,  is  obtained, 
whilst  the  filtrate  may  be  evaporated,  and  the  resulting  mixture 
of  neutral  fat  and  free  fatty  acid  further  examined  as  required. 

Burstyn's  Method. — A  physical  method  of  approximately 
determining  the  amount  of  free  acid  contained  in  oil  (more 
especially  olive  oil)  has  been  devised  by  Burstynf  for  use  in 
cases  where  titration  by  chemical  means  is  inconvenient  or 
impracticable.  100  c.c.  of  the  oil  to  be  tested  are  placed  in  a 
stoppered  cylinder  capable  of  holding  200  c.c.;  this  is  then  filled 
up  to  the  mark  with  alcohol  of  88  to  90  per  cent.,  and  the  whole 
well  shaken,  and  allowed  to  stand  two  or  three  hours.  The  alcohol 
floats  up,  having  dissolved  out  most  of  the  fatty  acids  together 
with  a  minute  amount  of  oil ;  the  increase  in  specific  gravity  is 
determined  by  testing  the  upper  layer  with  a  highly  delicate 
araeometer,  a  similar  cylinder  of  the  original  alcohol  used  being 
simultaneously  examined  side  by  side.  By  the  aid  of  a  table 

*  In  presence  of  alcohol  ether  is  apt  to  take  up  into  solution  small 
quantities  of  soap,  as  well  as  neutral  fat. 

t  Dingier 's  Polyt.  Journal,  ccxvii.,  p.  314;  also  Journal  Chem.  Soc., 
vol.  i.  (1876),  p.  769. 


DETERMINATION    OF    UNSAPONIFIABLE    CONSTITUENTS.  11-9 

the  amount  of  free  fatty  acid  is  deduced  from  the  increment  in 
specific  gravity  indicated,  the  table  being  so  constructed  as  to 
allow  for  the  solubility  in  alcohol  of  the  neutral  oil,  etc.  Apart 
from  the  error  introduced  by  the  possible  presence  of  varying 
amounts  of  phytosterol,  or  other  vegetable  substances  more  or 
less  soluble  in  alcohol,  a  very  slight  difference  in  temperature 
between  the  vessels  containing  the  alcoholic  oil  solution  and  the 
pure  alcohol  used  for  comparison  produces  a  great  effect  on  the 
result.  The  table  is  usually  arranged  so  as  to  show  the  number 
of  "  Burstyn  degrees  "  of  free  acid — i.e.,  the  number  of  c.c.  of 
normal  alkali  neutralised  by  the  free  acid  contained  in  100  c.c. 
of  the  oil  examined.  "One  degree"  consequently  represents 
0-282  gramme  of  oleic  acid  per  100  c.c.,  or  close  to  0'3  per  cent, 
by  weight. 


DETERMINATION  OF  UNSAPONIFIABLE 
CONSTITUENTS. 

The  unsaponifiable  matters  contained  in  many  oils  and  fats 
to  the  extent  of  a  few  tenths  per  cent.,  are  most  conveniently  de- 
termined by  saponifying  the  oil  with  alcoholic  alkali,  evaporating 
off  the  spirit,  and  dissolving  out  matters  soluble  in  such  solvents 
as  ether,  chloroform,  carbon  disulphide,  light  petroleum  spirit, 
«fec.,  either  by  means  of  an  extraction  arrangement,  such  as  the 
Soxhlet  apparatus  described  in  Chap,  ix.,  or  by  adding  water  and 
agitating  with  the  solvent.  Ether  frequently  dissolves  a  small 
amount  of  soap ;  on  the  other  hand,  small  quantities  of  oil 
often  escape  saponification,  and  are  thus  extracted ;  so  that  it 
is  always  preferable  to  boil  a  second  time  with  alcoholic  alkali 
the  residue  left  on  evaporating  off  the  solvent,  and  repeat  the 
extraction  process  with  the  product.  The  extraction  by  means 
of  a  Soxhlet  arrangement  is  generally  facilitated  by  placing  some 
sand  or  powdered  pumice-stone  in  the  evaporating  vessel  em- 
ployed, and  rubbing  up  therewith  the  residual  soap  left  after 
evaporating  off  the  alcohol ;  the  solvent  thus  obtains  more  easy 
access  to  the  matters  to  be  dissolved  out,  and  the  operation  is 
effected  more  quickly  and  thoroughly. 

In  the  analysis  of  soaps  similar  methods  are  often  employed ; 
the  soap  to  be  tested  is  reduced  to  thin  shavings  which  are 
then  cautiously  dried,  first  at  a  comparatively  low  temperature 
(50°-60°  C.),  later  on  at  steam  heat  or  a  little  above,  so  as  to 
drive  off  all  moisture  without  fusing  the  mass.  The  dried 
shavings,  coarsely  powdered,  are  packed  in  the  Soxhlet  tube 
and  exhausted  with  solvent,  preferably  light  petroleum  ether; 
in  this  way  unsaponified  fat  contained  in  the  soap,  cholesterol 
and  analogous  substances  derived  from  the  oils  and  fats  em- 
ployed, waxy  matter  or  hydrocarbons  (e.g.,  paraffin  oil)  added  to 


120  OILS,    FATS,    WAXES,    ETC. 

the  soap,  or  contained  in  the  materials  (e.g.,  in  distilled  oleins), 
and  similar  constituents  are  all  dissolved  out,  giving  a  solution, 
the  residue  left  on  evaporation  of  which  is  further  examined  ; 
whilst  the  purified  soap  is  also  subjected  to  analysis. 

The  modification  of  Soxhlet's  extraction  apparatus  described 
by  Honig  and  Spitz  (Chap,  ix.),  is  often  very  convenient  for  dis- 
solving out  the  unsaponifiable  constituents  soluble  in  ether,  light 
petroleum  spirit,  &c.,  after  heating  with  excess  of  alcoholic  alkali, 
evaporating  off  the  spirit,  and  dissolving  in  a  minimum  of  water. 
The  use  of  petroleum  spirit  is  preferable,  as  although  it  often 
dissolves  out  a  little  soap  (though  usually  less  than  ether),  this 
may  be  readily  removed  by  agitating  with  a  mixture  of  equal 
quantities  of  alcohol  and  water  (50  per  cent,  spirit),  when  the 
petroleum  solution  free  from  soap  floats  up.  Moreover,  ethereal 
liquids  often  form  froths  that  remain  permanent 
without  separating  properly  for  many  hours 
or  even  days ;  petroleum  spirit  is  less  liable  to 
this  inconvenience. 

In  cases  where  a  portion  only  of  the  ethereal 
or  other  solution  is  intended  to  be  drawn  off, 
this  is  readily  effected  by  running  the  solution 
and  watery  fluid  into  a  graduated  vessel,  into 
the  mouth  of  which  a  doubly  perforated  cork  is 
fitted,  with  a  washbottle-like  arrangement  of 
tubes  (Fig.  27,  Chattaway).  The  upper  and 
lower  levels  of  the  ethereal  liquid  being  read  off, 
the  cork  and  tubes  are  inserted,  and  air  blown 
in  so  as  to  force  out  some  of  the  ethereal  solu- 
tion into  a  weighed  dish  in  which  it  is  sub- 
sequently evaporated,  the  quantity  thus  drawn 
off  being  known  by  withdrawing  the  tubes  and 
reading  off  the  difference  of  level  of  the  top  of 
Fig  27  the  ether  stratum.  When  sharp  results  are  re- 

quired, about  90  to95per  cent,  of  the  ether  should 
thus  be  withdrawn,  and  the  remainder  diluted,  say  tenfold,  by  add- 
ing more  ether;  the  bulk  of  this  is  similarly  forced  out,  so  that  the 
remaining  ether  only  represents  a  small  percentage  of  the  original 
ethereal  solution.  Thus,  suppose  that  the  original  ethereal  fluid 
measures  58  c.c.,  of  which  52  are  removed  by  the  first  blowing 
out,  leaving  6.  This  is  diluted  to  60,  and  another  50  c.c.  blown 
out,  leaving  10  of  the  more  dilute  liquid,  representing  1  of  the 

original    solution,    or    1   x  — —  =  1'72  per  cent,  thereof.     Then 

Oo 

100  -  1-72  =  98-28  per  cent,  of  the  original  solution  has  been 
blown  off,  so  that  the  weight  of  the  residue  obtained  therefrom 

58        100 
by  evaporation  must  be  increased  in  the  proportion  -^=  =  ^T^TT- 

0  i          i/o  **jO 

Oils,   &c.,    adulterated   with   any   considerable   proportion   of 


DETERMINATION    OF    UNSAPONIFIABLE    CONSTITUENTS.         121 

hydrocarbons  (paraffin,  petroleum,  rosin  oil,  &c.),  or  similar 
mixtures  intentionally  prepared  for  lubricating  purposes,  «fec.,  are 
easily  separated  by  the  above  treatment ;  when  the  fatty  acids 
contained  in  the  saponifiable  constituents  are  required  to  be 
further  examined,  they  are  readily  isolated  by  dissolving  in  hot 
water  the  soap  thus  freed  from  hydrocarbons,  and  acidulating 
with  a  mineral  acid. 

Blubber  oils  containing  the  glycerides  of  higher  ethylic  alcohols 
(cetylic  alcohol,  &c.)  when  thus  treated  yield  to  the  solvent  the 
alcoholiform  constituents  set  free  during  saponification ;  when 
these  are  mixed  with  hydrocarbons  the  proportion  of  alcohol 
present  may  be  arrived  at  by  means  of  the  hydrogen  test  (p.  13), 
or  the  acetylation  test  (Chap,  viu.) 

When  only  minute  quantities  of  unsaponifiable  matters  are 
contained  in  a  given  oil  or  fat,  &c.,  these  are  generally  either 
substances  akin  to  cholesterol  and  phytosterol  dissolved  in  the 
oil,  or  else  matters  of  mucilaginous  or  albuminous  character 
either  dissolved  in  the  oil  or  suspended  in  a  diluted  jelly-like 
form  therein.  The  former,  when  dissolved  out  from  the  soap 
resulting  after  saponification  by  such  solvents  as  ether  or  benzo- 
line,  may  often  be  obtained  in  a  crystallised  condition  by 
dissolving  in  hot  alcohol  and  cooling,  or  may  be  converted 
into  benzoic  or  acetic  ethers,  &c.,  and  identified  either  by  the 
melting  point  or  the  "  acetyl  number."  The  latter  are  left  un- 
dissolved ;  on  decomposing  the  soaps  with  a  mineral  acid  they 
form  flocculent  masses,  from  which  the  pure  molten  fatty  acids 
are  readily  separable  by  filtration  through  a  dry  paper  filter  after 
separation  from  the  aqueous  liquor.  Some  oleaginous  matters,, 
extracted  by  solvents  (such  as  carbon  disulphide)  from  certain 
vegetables,  seeds,  &c.,  or  from  certain  kinds  of  animal  fatty 
matter,  contain  complex  bodies  of  the  nature  of  lecithin,  a  sort 
of  compound  ether  of  choline,  glycerophosphoric  acid,  and  fatty 
acids  (oleic  and  stearic) ;  phosphorised  constituents  of  this  kind 
are  largely  contained  in  the  oily  matter  from  the  yolks  of  hens' 
eggs,  and  to  a  lesser  extent  in  that  from  the  seeds  of  certain 
leguminous  plants,  e.g.,  peas  (vide  p.  123). 

Matters  of  a  saponaceous  character  are  sometimes  contained 
in  commercial  oils,  owing  either  to  the  use  of  basic  sub- 
stances in  refining  (especially  in  boiling  drying  oils),  whereby 
more  or  less  considerable  amounts  of  metallic  soaps  are  formed 
and  partially  dissolved  by  the  oil ;  or  to  other  causes,  such  as  the 
intentional  addition  of  metallic  soaps  (aluminium,  magnesium, 
zinc,  ttc.)  for  the  purpose  of  increasing  the  viscosity  of  lubricating 
oils ;  or  simultaneous  contact  with  air  and  metals,  whereby  a 
metallic  oxide  is  formed,  which  then  is  either  dissolved  as 
metallic  soap,  in  virtue  of  free  fatty  acids  present,  or  reacts  on 
the  glyceride,  forming  metallic  soap  by  saponification.  Oils  that 
have  been  in  contact  with  copper  or  brass  are  often  rendered 


122  OILS,    FATS,    WAXES,    ETC. 

green  by  the  formation  of  copper  soap  in  this  way ;  similarly, 
drying  oils  that  have  been  "  boiled "  with  metallic  oxides  as 
driers  (e.g.,  lead  oxide)  generally  contain  more  or  less  metallic 
soap  in  solution  thence  derived.  Such  admixtures,  whether 
intentional  or  not,  can  generally  be  estimated  by  diluting  the  oil 
with  ether  free  from  alcohol,  and  filtering,  when  the  metallic  soap 
is  left  undissolved  ;  by  decomposing  this  with  dilute  nitric  acid 
the  metallic  constituents  are  obtained  as  nitrates.  In  most 
<jases  prolonged  agitation  of  the  oil  with  highly  dilute  nitric  acid 
suffices  to  dissolve  out  the  metallic  oxides  present  as  soaps,  and 
in  this  way  errors  are  avoided  due  to  solubility  of  metallic  soaps 
in  the  ethereal  solution  of  oil. 

Oils  containing  lead  or  copper  are  more  or  less  blackened  by 
shaking  up  with  a  few  drops  of  sulphuretted  hydrogen  water,  or 
dilute  solution  of  ammonium  sulphide.  Preferably  a  mixture  of 
equal  volumes  of  glycerol  and  water  is  used  to  dissolve  the 
sulphur  compound  employed,  as  this  then  acts  more  readily  on 
the  oil. 

Oils  containing  potash  and  soda  soaps  in  solution  generally 
yield  these  more  or  less  completely  to  water  when  shaken  up 
therewith,  so  that  by  allowing  to  stand  and  separating  the 
aqueous  liquid,  the  soaps  dissolved  therein  can  be  obtained  by 
evaporation  to  dry  ness. 

Water  contained  in  Oils,  &c. — Although  "  oil  and  water  " 
are  conventionally  regarded  as  immiscible  substances,  still  their 
mutual  insolubility  is  in  most  cases  relative  rather  than  absolute. 
Water  in  general  dissolves  extremely  little  oil  or  fat ;  but  the 
converse  does  not  hold  so  closely,  as  a  few  tenths  per  cent,  of 
water  can  generally  be  retained  in  permanent  solution  by  fluid 
oils,  &c.,  without  impairing  their  transparency.  In  the  case  of 
semisolid  substances  (e.g.,  butter  and  lard),  much  larger 
quantities  of  water  can  be  mechanically  intermixed  with  the  fat 
in  the  form  of  minute  globules  interspersed  throughout  the  mass  ; 
but  in  this  case  there  is  no  true  solution,  and  on  gently  warming 
the  mass  so  as  to  melt  the  fatty  matter,  the  water  gradually 
separates  out  to  the  bottom,  so  that  if  the  operation  be  effected 
in  a  graduated  vessel,  the  volume  of  water  thus  separating  may 
be  by  and  by  read  off.  In  some  cases,  the  separation  of  the 
water  in  this  way  is  facilitated  by  adding  to  the  just-fused  mass 
a  sufficient  quantity  of  light  petroleum  spirit  to  prevent  it 
solidifying  on  cooling,  and  setting  by  the  whole  in  a  corked-up 
graduated  tube  for  some  time,  so  as  to  allow  the  water  globules 
to  collect  and  run  together.  The  amount  of  admixed  water  may 
also  be  determined  by  heating  a  known  weight  of  substance  to  a 
temperature  a  little  above  100°  C.  (by  means  of  an  airbath,  &c.), 
and  noting  the  loss  of  weight. 

When  the  actually  dissolved  water  is  to  be  determined,  the 
same  process  may  be  used;  preferably,  however,  the  oil,  <fcc.,  to 


DETERMINATION    OF    UNSAPONIFIABLE    CONSTITUENTS.  123 

be  examined  is  not  heated  in  contact  with  air,  but  is  placed  in  a 
weighed  U  tube,  through  which  a  current  of  dry  carbon  dioxide 
gas  is  passed,  to  prevent  oxidation  by  absorption  of  oxygen  from 
the  atmosphere  during  the  heating. 

Adulteration  of  Fats  with  Suspended  Matters. — Solid  and 
semisolid  fats  (lard,  tallow,  Arc.,)  are  sometimes  intentionally 
adulterated  by  admixture  with  white  weight-giving  substances, 
such  as  china-clay,  starch,  &c.  To  determine  the  quantity  arid 
nature  of  the  adulterants  present  in  such  cases,  the  fat,  £c.,  is 
thinned  with  carbon  disulphide  or  other  volatile  solvent,  and 
filtered  through  a  dry  weighed  filter.  The  filtrate  and  washings 
being  evaporated  to  dry  ness,  and  the  residue  dried  in  a  steam 
bath,  the  proportion  of  actual  fat  present  is  known ;  the  increment 
in  weight  of  the  filter  represents  the  solid  adulterant,  and  the 
deficiency  in  weight  the  water.  The  residue  on  the  filter  turns 
blue  if  starch  is  present  (flour,  meal,  farina,  (fee.);  cold  water 
dissolves  out  common  salt  and  such  like  saline  matters  (e.g.,  in 
salted  butters,  &c.) ;  kaolin  and  sand  are  left  behind  on  incinera- 
tion, whilst  albuminoid  and  caseous  matters,  cellulose,  mucilage, 
and  other  vegetable  non-fatty  extractives  are  burnt  off  during  the 
process.  Oils  that  have  been  refined  by  means  of  sulphuric  acid 
and  retain  minute  quantities  of  free  inorganic  acid,  when  thus 
treated  with  a  solvent  and  filtration,  leave  on  the  filter  paper 
a  minute  amount  of  residue  soluble  in  water  with  acid  reaction  ; 
this  may  be  titrated  with  deciiiormal  alkali  in  the  usual  way. 

Sulphurised  and  Phosphorised  Constituents. — Certain 
oils,  more  especially  those  derived  from  cruciferous  plants  (rape, 
camelina,  mustard,  horseradish,  cress,  &c.),  contain  small  quan- 
tities of  sulphurised  constituents,  such  as  thiocyanic  ethers ;  the 
presence  of  these  may  be  qualitatively  tested  by  heating  the  oil 
with  concentrated  potash  solution,  whereby  potassium  sulphide  is 
formed;  the  mass,  after  dilution  with  water  and  separation  of 
the  aqueous  liquor,  gives  a  brown  or  black  coloration  with 
potassium  plumbate.  In  some  cases,  heating  the  oil  to  "boiling" 
with  a  bright  strip  of  silver  causes  the  latter  to  blacken.  To 
•determine  the  amount  of  sulphur,  the  oil  is  dissolved  in  sulphur- 
free  petroleum  or  alcohol,  and  burnt  in  the  manner  employed  in 
determining  sulphur  in  coal  gas,  the  flame  being  enclosed  in  a 
chimney  connected  with  an  aspirator,  and  absorbing  tubes  filled 
with  moistened  glass  beads  being  interposed,  so  as  to  condense 
sulphur  dioxide  and  trioxide  along  with  the  water  formed  by 
the  combustion;  a  tray  with  fragments  of  solid  ammonium 
carbonate  is  fixed  over  the  flame,  to  furnish  an  ammoniacal 
atmosphere ;  the  condensed  liquid  is  oxidised  with  bromine 
water,  and  precipitated  with  barium  chloride  and  hydrochloric 
acid  (Allen).  Or  the  oil  may  be  cautiously  heated  with  alcoholic 
potash,  evaporated,  and  the  residue  incinerated  with  addition  of 
potassium  nitrate  till  white,  the  sulphate  formed  being  determined 


124  OILS,    FATS,    WAXES,    ETC. 

as  usual.  This  latter  method  is  also  available  for  the  estimation 
of  phosphorus,  present  in  certain  oils  and  fats  as  a  compound  of 
the  nature  of  lecithin,  the  phosphorus  being  ultimately  weighed 
as  magnesium  pyrophosphate  (Benedikt). 

The  following  general  scheme  for  the  examination  of  oils  and 
fats,  &c.,  is  applicable  in  most  cases  so  far  as  the  above  mentioned 
impurities  or  constituents  are  concerned  : — 

Dry  a  convenient  quantity  so  as  to  determine  the  amount  of 
water  present  (p.  122). 

Melt  a  known  weight  of  fat  and  pass  it  through  a  hot  weighed 
filter,  finally  washing  out  the  adherent  fat  with  ether ;  the 
residue  left  on  the  filter  may  contain  saline  matters,  suspended 
organic  impurities,  dust,  tfec.,  &c.,  which  may  be  further  ex- 
amined as  occasion  requires.  On  incinerating  the  filter,  the 
amount  of  inorganic  suspended  matter  is  obtained.  Part  of  the 
filtered  oil,  &c.,  may  be  shaken  successively  with  water  to  dis- 
solve out  alkaline  soapy  matters,  and  with  dilute  nitric  or 
sulphuric  acid  in  case  any  lead,  copper,  or  other  metallic  soaps 
are  present,  the  watery  and  acid  liquors  being  separated  and 
examined.  The  oil  may  advantageously  be  diluted  with  ether 
or  carbon  disulphide,  &c.,  previously  to  agitation  with  water,  <fec. 
Another  part  of  the  filtered  oil  is  diluted  with  warm  alcohol,  and 
the  free  acid  number  determined  (p.  116),  using  phenolphthalein 
as  indicator ;  the  alcohol  is  evaporated  and  the  residue  taken  up 
with  light  petroleum  spirit,  &c.  ;  the  residual  soap  formed  from 
the  free  acid  is  examined  as  required  (Chap,  xxi.)  for  fatty  acids, 
resin  acids,  <fcc.  Aluminium  and  other  metallic  soaps  may  also  be 
here  present,  precontained  in  the  oil. 

The  light  petroleum  spirit  solution  011  evaporation  gives  a 
residue  containing  neutral  oil,  hydrocarbons,  and  unsapoiiifiable 
matters,  £c. ;  this  is  saponified  with  alcoholic  alkali,  and  the  pro- 
duct diluted  with  water  and  shaken  with  ether  or  petroleum 
spirit;  the  ethereal  solution  is  evaporated  and  the  treatment 
with  alcoholic  alkali  repeated  to  ensure  complete  saponification  ; 
finally,  the  hydrocarbons,  &c.,  are  dissolved  out  by  ether  or 
petroleum  spirit,  and  the  watery  solution  of  glycerol  and  fatty 
acid  soaps  further  examined  by  acidifying  and  separating  the 
fatty  acids ;  these  usually  constitute  95  to  96  per  cent,  of  the 
original  glycerides  (Chap,  vin.) 


EFFECT    OF    HEAT    ON    OILS.  125 


CHAPTER  VII. 

CHEMICAL  REACTIONS  OF  OILS,  FATS,  &c.,  AND 
THEIR  USES  AS  TESTS  OF  PURITY,  &c. 

EFFECT  OF  HEAT  ON  OILS,  &c. 

WHEN  fixed  oils,  &c.,  are  subjected  to  heat,  decomposition  is 
sooner  or  later  brought  about ;  if  the  oil  is  a  glyceride,  acroleiri 
(acrylic  aldehyde,  C2~H3.COH)  is  generally  evolved,  so  named  on 
account  of  the  acrid  character  of  its  vapour.  In  some  cases  the 
fatty  acid  originally  present  as  glyceride  is  also  volatilised  un- 
changed in  greater  or  less  quantity  ;  but  in  general,  destructive 
distillation  only  takes  place.  If  the  heating  be  carried  out  in 
presence  of  water  vapour,  as  when  superheated  steam  is  blown 
through  the  mass,  in  many  cases  hydrolysis  takes  place,  fatty 
acids  and  glycerol  being  produced,  which  more  or  less  completely 
pass  off  along  with  the  water  vapour ;  on  this  action  are  based 
certain  processes  for  the  manufacture  of  free  fatty  acids  for  candle 
making,  £c.,  and  for  preparing  pure  glycerol. 

When  drying  oils,  more  especially  linseed,  poppy,  and  walnut 
oils,  are  heated  for  the  purpose  of  preparing  "  boiled  "  oil  for  the 
manufacture  of  paint,  ttc.,  and  particularly  when  the  action  is 
pushed  to  a  great  length,  as  in  the  manufacture  of  printing 
ink,  the  glyceridic  portion  of  the  compounds  appears  to  be 
almost  completely  decomposed,  the  linolic  acid  or  anhydride 
developed  being  more  or  less  dehydrated  (and  probably  poly- 
merised) in  such  fashion  as  to  form  a  highly  viscid  or  rubber-like 
mass.  Oxidation  by  direct  addition  of  oxygen  so  as  to  form 
oxylinolic  acid  and  derivatives  thereof  usually  occurs  simul- 
taneously, more  especially  in  the  "  blowing  "  process  of  preparing 
boiled  oils. 

Flashing  Point. — The  determination  of  the  temperature  at 
which  inflammable  vapours  are  given  oif  (whether  by  simple 
volatilisation,  or  in  consequence  of  decomposition)  in  sufficient 
quantity  to  take  fire  by  the  application  of  a  light  to  the  mixture 
of  air  and  vapour  contained  in  the  upper  part  of  the  heating 
vessel,  is  a  somewhat  important  operation  in  the  case  of  many 
oils  intended  for  lubricating  and  other  purposes,  where  they  are 
liable  to  be  considerably  heated  ;  with  animal  and  vegetable  oils 
the  "  flashing  points  "  are  generally  high,  but  much  lower  num- 
bers are  often  given  by  mixtures  containing  hydrocarbon  oils, 
such  as  paraffin  oil  and  petroleum  distillates,  rosin  oils,  and  such 


126 


OILS,    FATS,    AVAXES,    ETC. 


like  products.  For  the  determination  of  the  flashing  point  of 
petroleum  distillates  and  similar  substances,  several  special  forms 
of  instrument  have  been  devised  by  different  experimenters ;  in 
some  of  the  earlier  forms  the  vapour  emitted  from  the  warmed 
oil  was  allowed  free  access  to  the  air  ;  this  mode  of  operating  was 
known  as  the  "  open  test,"  and  was  subject  to  serious  irregulari- 
ties according  to  the  way  in  which  the  heating  was  conducted, 
and  so  on.  In  the  later  instruments  the  top  of  the  heating  vessel 
is  closed  in  to  prevent  the  escape  of  inflammable  vapours  when 
first  generated  ;  in  consequence  a  considerably  lower  tempera- 
ture is  registered  by  the  application  of  the  "  close  test,"  whilst 
the  sources  of  fluctuation  in  the  results  are  much  lessened. 

Fig.  28  represents  Abel's 
flashing  point  apparatus, 
used  in  Britain  as  the  legal- 
ised appliance  for  testing 
petroleum,  £c.,  under  the 
Petroleum  Act.  Similar  ar- 
rangements are  in  use  in 
other  countries  with  minor 
modifications,  partly  as  to 
the  construction  of  the  in- 
strument itself,  and  partly 
as  to  the  exact  details  of 
manipulation  to  be  observed 
during  use  ;  for  as  the  tem- 
perature values  deduced  are 
liable  to  slight  fluctuation 
with  variations  in  the  mode 
of  heating,  etc.,  a  definite 
prescribed  mode  of  operating 
must  be  strictly  adhered  to. 
Abel's  apparatus  consists  of 
a  cylindrical  metal  cup,  Af 
placed  inside  another  with  an 
Fig.  28.  air-space  between,  the  outer 

one  being  surrounded  by  a 

water  bath,  B,  heated  by  a  lamp,  K,  underneath.  rlhe  oil  to  be 
tested  is  carefully  poured  in  without  splashing  until  just  level  with 
the  top  of  the  gauge,  C,  1 J  inches  from  the  bottom  of  the  cup,  the 
water  in  the  jacket  being  at  the  temperature  130°  F.  =  540<4  C., 
as  shown  by  the  thermometer,  H.  The  lid  of  the  cup,  D,  is  then 
put  on,  the  temperature  of  the  oil  being  known  by  means  of  the 
thermometer,  E.  A  small  lamp,  G,  is  arranged  at  the  top  of  the 
cover,  swinging  on  an  axis,  in  such  a  fashion  that  when  a  slide 
covering  an  aperture  in  the  lid  is  drawn  aside,  the  lamp  flame  is 
made  to  pass  over  the  aperture.  As  the  contents  of  the  cup 
slowly  heat  up,  the  slide  is  withdrawn  at  regular  intervals  of 


EFFECT    OF    HEAT    ON    OILS. 


127 


time,  governed  by  the  swinging  of  a  pendulum ;  by  and  by,  the 
inflammable  vapours  are  given  off  in  sufficient  quantity  to  yield 
a  flash  of  blue  flame  by  their  kindling  when  the  slide  is  with- 
drawn ;  the  temperature  then  indicated  by  the  thermometer,  E, 
is  noted  as  the  flashing  point.  Obviously  this  form  of  apparatus 
is  only  suitable  for  substances  the  flashing  point  of  which  is 
below  the  temperature  of  boiling  water ;  when  less  volatile  sub- 
stances are  to  be  examined,  the  water  jacket  is  replaced  by  a  hot 
bath  of  some  other  fluid  ;  or  a  hot  airbath  is  used  instead. 


Fig.  29. 

Pig.  29  indicates  Pensky's  modification  of  Abel's  instrument  for 
such  purposes,  where  the  source  of  heat  is  the  lamp  flame,  C, 
playing  on  wire  gauze,  D,  and  filling  the  inverted  basin,  A,  with 
hot  air.* 

*  An  improved  form  of  Pensky's  apparatus  has  been  described  by  Holde 
(Journ.  Soc.  Chem.  Ind.,  1889,  p.  734). 


128 


OILS,    FATS,    WAXES,    ETC. 


Lubricating  oils  containing  hydrocarbons  sufficiently  volatile 
to  flash  at  150°  C.  or  below  are  distinctly  unsafe  as  regards  risk 
of  fire.  Animal  and  vegetable  fixed  oils  (unmixed  with  hydro- 
carbons), as  a  rule,  do  not  flash  below  200°  to  250°  C. ;  thus 
A.  Kiinkler  gives  the  following  values  *  as  the  flashing  points 
observed  with  various  lubricating  fluids,  mostly  consisting  of 
petroleum  hydrocarbons,  and  some  natural  oils,  &c.  :• — 


Cylinder  oils  -  Russian, 
,,  American, 

Machine  oils — Russian, 
,,  American, 

Spindle    oils — Russian, 
,,  American, 

Rape  oil — crude, 
,,         refined, 

Olive  oil,  . 

Castor  oil, 

Linseed  oil, 

Tallow,      . 


Sp.  Gr.  at  17°  'o. 

Degrees  C. 

•9  11  --923 

183-238 

•886--S99 

280-283 

•893--920 

138-197 

•884--920 

187-206 

•893  --895 

163-167 

•908  --91  1 

187  200 

•920, 

265 

•911 

305 

•914 

205 

•963 

275 

•930 

285 

•951 

265 

Characteristic  Oxidation  Products. — In  certain  cases  the 
results  furnished  by  cautious  oxidation  afford  useful  indications 
of  the  nature  of  the  fatty  acids  ;  this  is  more  especially  the  case 
when  an  approximate  separation  of  liquid  and  solid  fatty  acids 
has  been  previously  effected  by  conversion  into  lead  salts  and 
treatment  with  ether,  so  as  to  dissolve  out  oleate  and  linolate 
of  lead,  <tc.,  leaving  undissolved  lead  stearate,  palmitate,  &c. 
Hazura  recommends  the  following  method  of  operating  : — The 
fatty  acids  obtained  by  decomposing  the  soluble  lead  salts  are 
neutralised  with  a  slight  excess  of  caustic  potash,  diluted  with 
60-70  parts  of  water,  and  the  liquid  treated  with  about  an 
equal  volume  of  a  solution  of  potassium  permanganate  added 
in  a  thin  stream  with  continuous  agitation.  After  ten  minutes 
sulphurous  acid  solution  is  similarly  added,  sufficient  to  dissolve 
all  precipitated  hydratecl  manganese  dioxide,  and  to  give  an 
acid  reaction.  The  products  of  oxidation  of  oleic  and  linolic 
acids  (dioxystearic  and  sativic  acids)  are  only  difficultly  soluble, 
and  consequently  precipitate ;  whilst  linusic  and  isolinusic 
acids  (the  oxidation  products  respectively  of  linolenic  and 
isolinolenic  acids)  remain  in  solution.  These  latter  acids  are 
extracted  by  neutralising  with  potash,  evaporating  to  a  small 
bulk  (one-twelfth  to  one-fourteenth  of  the  original  volume)  and 
decomposing  with  sulphuric  acid ;  the  precipitate  is  dried  in  the 
air,  treated  with  ether  to  dissolve  out  matters  readily  soluble 

*  Journ.  Hoc.  Chem.  Ind.,  1890,  p.  197;  from  Dinner's  Pol.  Journ.,  274, 
p.  276. 


SPONTANEOUS    OXIDATION    OF    OILS.  129 

therein,  and  the  residue  crystallised  from  alcohol  and  from  water 
so  as  to  separate  the  more  soluble  isolinusic  acid  from  the  less 
soluble  linusic  acid.  Dioxystearic  acid  and  sativic  acid  are 
separated  in  a  similar  way  from  the  precipitate  thrown  down  in 
the  earlier  stage  ;  the  precipitate  is  washed  with  a  little  ether  to 
remove  easily  soluble  fatty  acids  (unoxidised)  and  then  treated 
with  large  bulks  of  ether  (100  parts  ether  to  1  of  substance). 
Dioxystearic  acid  is  chiefly  dissolved  out,  obtainable  by  evapora- 
tion and  recrystallisation  of  the  deposited  crystals  from  alcohol 
twice  in  succession ;  whilst  sativic  acid  is  isolated  from  the 
insoluble  portion  by  boiling  with  water,  filtering  whilst  boiling 
hot,  and  crystallisation  on  cooling.  The  purified  acids  thus 
obtained  are  further  identified  by  means  of  their  melting  points 
(p.  43).  According  to  Benedikt  the  acetylation  test  (Chap,  viu.) 
may  also  be  usefully  employed  for  this  purpose. 

In  somewhat  similar  fashion  trioxystearic  and  isotrioxystearic 
acids  are  obtainable  from  the  fatty  acids  of  castor  oil.  It  is 
noteworthy  in  this  connection  that  the  acids  obtained  by  the 
oxidation  of  isoleic  acid  and  of  elaidic  acid  (the  isomeride  of 
oleic  acid  produced  by  the  action  of  nitrous  acid,  p.  28)  are 
dioxystearic  acids,  isomeric  but  not  identical  with  that  obtained 
from  ordinary  oleic  acid  (Saytzeff,  p.  30).  Similarly,  the  oxida- 
tion products  of  erucic  acid  and  its  elaido  derivative  brassic  acid, 
yield  two  isomeric  dioxybenic  acids  (p.  29). 

Spontaneous  Oxidation  of  Oils,  Fats,  &c. — Oils  of  the 
drying  class,  and  to  a  lesser  extent  many  other  oils  and  fats, 
possess  the  property  of  directly  absorbing  oxygen  from  the  air  at 
the  ordinary  temperature,  the  effect  being  much  more  marked 
when  more  or  less  heated ;  the  drying  and  hardening  of  paint 
prepared  from  linseed  oil  is  an  extreme  case  of  such  an  action, 
whilst  the  thickening  and  "  gumming "  of  various  other  oils  on 
keeping  exhibits  the  same  kind  of  phenomenon  in  a  lesser 
degree.  The  fixation  of  oxygen  during  actions  of  this  kind 
appears  to  be  principally  due  to  a  direct  combination  of  oxygen 
with  acid  radicles  of  "  unsaturated  "  character,  precisely  analogous 
to  the  combination  therewith  of  iodine  or  bromine  (p.  31,  45);  as 
the  oxidation  proceeds,  the  "iodine  absorbing  power"  of  the 
substance  usually  diminishes  pari  passu. 

In  some  cases  the  rapidity  with  which  the  absorption  of  oxygen 
takes  place  is  greatly  enhanced  by  heating  the  oil  to  a  tempera- 
ture insufficient  to  produce  any  great  degree  of  decomposition, 
although  high  enough  to  cause  incipient  breaking-up  with  evolu- 
tion of  vapours ;  this  process  of  "  boiling "  oil,  especially  when 
certain  metallic  compounds  or  "driers"  are  added,  appears  to 
consist  essentially  in  the  formation  of  substances  that  act  as 
"  carriers  "  of  oxygen  ;*  so  that  "  boiled  oils  "  dry  more  rapidly 

*  The  rotting  of  painted  canvas  sometimes  observed  appears  to  be  largely 
due  to  oxidation  of  the  fibres  of  the  fabric  in  consequence  of  this  carrier 

9 


130 


OILS,    FATS,    WAXES,    ETC. 


than  the  same  oils  in  a  raw  or  unboiled  condition,  these  carriers 
absorbing  oxygen  more  rapidly  from  the  air,  and  parting  with  it 
again  to  the  unoxidised  portions  of  the  oil.  Free  exposure  to 
air  whilst  heating,  in  some  cases  accompanied  by  the  injection  of 
a  current  of  air  through  the  heated  mass,  appears  to  be  essential 
to  the  production  of  the  initial  degree  of  oxidation  effected  in 
the  boiling  of  drying  oils ;  the  latter  process  when  applied  to 
various  non-drying  oils  (more  especially  fish  oils),  causes  a  con- 
siderable increase  in  density  and  viscidity,  so  that  "  blown  oils  " 
thus  prepared  are  more  suitable  for  lubricating  and  other 
purposes  than  the  original  untreated  substances. 

Effect  of  Light  on  Oils. — Exposure  to  light  produces  a- 
remarkable  increase  in  the  rate  at  which  spontaneous  oxidation 
of  oils,  &c.,  takes  place  at  the  ordinary  temperature  j  the  result 
of  this  oxidation  is  uniformly  to  cause  an  increment  in  specific 
gravity  and  in  the  amount  of  heat  evolved  on  mixture  with 
sulphuric  acid  (infra),  together  with  a  decrement  in  the  iodine  ab- 
sorption (Chap,  viu.)  Thus,  the  following  figures  were  obtained 
(along  with  many  others)  by  H.  Ballantyne  *  with  olive,  castor,, 
rape,  cotton  seed,  arachis,  and  linseed  oils ;  specimens  kept  in 
the  dark  for  six  months  showed  little  or  no  alteration  whether 
in  tightly  corked  or  open  bottles,  and  whether  undisturbed  or 
agitated  daily  so  as  to  aerate  them  ;  whereas  similar  specimens 
exposed  to  sunlight  during  the  same  period  exhibited  perceptible 
amounts  of  alteration,  even  when  kept  undisturbed  in  corked 
bottles ;  and  much  larger  amounts  when  kept  in  uncorked 
bottles  and  agitated  daily  : — 


VARIATION  IN  SPECIFIC  GRAVITY. 


Value  after  Six  Months'  Exposure 

Original  Value, 

to  Sunlight. 

practically 

Unchanged  in  the 

Dark. 

Undisturbed, 

Agitated  Daily, 

Corked. 

Uncorked. 

Olive  oil,     . 

•9168 

•9185 

•9246 

Castor  oil,  . 

•9679 

•96S3 

Rape  oil, 
Cotton  seed  oil,  . 

•9108 
•9225 

•9171 
•9236 

•9207 
•9320 

Arachis  oil, 

•9209 

•9216 

•9267 

Linseed  oil, 

•9325 

•9327 

•9385 

action.     The  presence  of  certain  kinds  of   resinous  matter  (such  as  are 
employed  in  the  manufacture  of  tarpaulins,   &c.),  seems  to  diminish  the 
tendency  to  this  destructive  action. 
*  Journ.  Soc.  Chem.  Int.,  1891,  p.  29. 


EFFECT    OF    LIGHT    ON    OILS. 

VARIATION  IN  IODINE  ABSORPTION. 


131 


• 

Value  after  Six  Months'  Exposure 

Original  Value, 

to  Sunlight. 

practically 
Unchanged  in  the 

Dark. 

:  Undisturbed, 
'      Corked. 

Agitated  Daily, 
Uncorked. 

Olive  oil, 

83-16 

82-64 

78-24 

Castor  oil,  . 

83-63 

83-27 

Rape  oil, 

105-59 

105-27 

102-12 

Cotton  seed  oil, 

106-84 

106-40 

100-12 

Arachis  oil, 

98-67 

97-60 

93-20 

Linseed  oil, 

173-46 

172-88 

166-17 

VARIATION  IN  HEAT  EVOLUTION  WITH  SULPHURIC  ACID. 


Values  after  Keeping  Six  Months 

In  the  Dark. 

In  Sunlight. 

Undisturbed, 
Corked. 

Agitated 
Daily, 

Uncorked. 

Undisturbed, 
Corked. 

Agitated 
Daily, 
Uncorked. 

Olive  oil, 

44° 

43°  -5 

47° 

67° 

Castor  oil, 

73° 

73° 

74°  -5 

78°-5 

Rape  oil, 

61°-5 

60°  -5 

63° 

72°  -5 

Cotton  seed  oil, 

75°  "5 

76°  -5 

76°  -5 

100° 

Arachis  oil,    . 

73°  -5 

73°  -5 

77° 

90° 

Linseed  oil,    . 

11  3°  -5 

112°  -5 

120° 

131° 

Only  minute  amounts  of  free  acid  were  developed  in  six  months 
during  the  course  of  these  observations,  indicating  but  little 
hydrolysis  of  glycerides  during  the  oxidation  of  the  insolated 
samples ;  the  maximum  amounts  formed  were  in  the  case  of 
linseed  and  cotton  seed  oils,  and  corresponded  with  a  develop- 
ment of  0*3  4  and  0*50  per  cent,  respectively  of  free  acid 
(expressed  as  oleic  acid)  in  sunlight,  none  at  all  being  formed 
in  the  dark.  Olive  oil  kept  six  months  in  the  dark  gave  a  hard 
solid  elaidin ;  that  exposed  to  sunlight  in  corked  bottles  with- 
out agitation  a  somewhat  less  hard  mass ;  but  that  insolated 
and  agitated  daily,  so  as  to  expose  as  thoroughly  as  possible 
to  oxidising  influences,  did  not  even  thicken  when  sub- 
mitted to  the  elaidin  test.  Similarly  Becchi's  silver  test  for 
cotton  seed  oil  gave  only  faint  indications  with  the  insolated 
oxidised  oil,  although  reacting  thoroughly  with  oil  kept  in  the 
dark.  The  viscosity  of  rape  oil,  as  indicated  by  the  efflux 


132  OILS,    FATS,    WAXES,    ETC. 

test  (p.  95),  was  notably  increased  by  nine  months'  exposure 
to  sunlight  (in  corked  bottles  without  agitation) ;  oil  kept 
in  the  dark  giving  times  of  flow  56  at  15° -5  and  25-5  at  50°, 
whilst  insolated  oil  gave  66  at  150<5  and  26-5  at  50°.  Castor  oil, 
mainly  consisting  of  the  glycerides  of  acids  already  oxidised,  as 
might  a  priori  be  expected,  is  less  changed  by  oxidation  than 
any  of  the  others. 

Similar,  but  less  systematic,  observations  have  been  recorded 
by  various  other  experimenters,  the  general  result  of  which  is 
to  show  that  the  changes  brought  about  in  oils  and  fats  by 
keeping  and  atmospheric  oxidation  are  greatly  accelerated  by 
the  influence  of  light.  According  to  E.  Ritsert  rancidity  is  only 
produced  in  oils  in  presence  of  oxygen  (air),  the  action  being 
greatly  accelerated  by  simultaneous  exposure  to  light.  No 
effect,  however,  is  produced  by  the  action  of  light  alone,  when 
access  of  oxygen  is  entirely  excluded. 

Spontaneous  Combustion. — When  a  film  of  readily  oxidisable 
oil  is  spread  over  a  considerable  surface,  so  that  a  large  area  is  pre- 
sented for  atmospheric  oxidation,  if  the  circumstances  are  such 
that  the  heat  generated  by  the  action  is  not  readily  lost,  the  mass 
heats  greatly,  in  some  cases  to  such  an  extent  as  to  bring  about 
spontaneous  inflammation.  Gellatly  has  shown  that  greasy 
cotton  rags  and  similar  materials  kept  in  a  warm  place  are, 
in  consequence,  liable  to  ignite  spontaneously,  and  are  accord- 
ingly a  source  of  danger  as  regards  fire.  Boiled  linseed  oil 
appears  to  be  the  most  energetic  of  oils  in  this  respect ;  a 
handful  of  cotton  waste  soaked  in  this  fluid  and  squeezed  out, 
and  then  kept  in  a  box  at  70°  to  80",  soon  rises  greatly  in 
temperature  to  near  200° ;  in  little  more  than  an  hour  the  mass 
is  so  hot  that  smoke  issues,  and  on  opening  the  box  the  whole 
takes  fire.  Unboiled  linseed  oil  takes  a  much  longer  time  to 
produce  the  same  result  *  (from  four  to  six  hours),  and  rape  oil 
longer  still  (some  ten  hours).  On  the  other  hand,  an  admixture 
of  mineral  oil  greatly  retards  the  action.  In  general,  the  ten- 
dency to  spontaneous  oxidation  is  greater  the  greater  the  iodine 
absorption  of  the  oil. 

A  testing  apparatus  has  been  constructed  by  Allbright  & 
Clark  f  for  determining  the  comparative  liability  of  oils  to 
spontaneous  combustion,  consisting  of  an  outer  shell  formed  by 
a  six  inch  wrought  iron  tube  which  can  be  closed  at  each  end  by 
discs  of  wood.  Inserted  into  this  tube  is  an  inner  four  inch 
sheet  iron  tube  with  overlapping  metal  covers  at  each  end,  so 
that  an  air  space  is  left  of  one  inch  around  the  inner  tube,  and  of 
three  inches  at  each  end  ;  three  thermometers  are  inserted  into 
the  inner  shell  through  the  outer  one.  A  ball  of  say  50  grammes 

*  Renouard,  Journ.  Soc,  Chem.  Ind.,  1882,  p.  184,  has  repeated  and  con- 
firmed this  difference  between  boiled  and  raw  linseed  oil. 
t  Journ.  Soc.  Chem.  Industry,  1892,  p.  547. 


ABSORPTION    OF    OXYGEN    BY    OILS.  133 

of  waste,  over  which  an  equal  weight  of  oil  is  distributed,  is  care- 
fully pushed  to  one  end  of  the  inner  tube,  and  the  corresponding 
thermometer  bulb  inserted  into  the  middle  of  the  ball.  A 
similar  ball  of  unoiled  waste  is  placed  at  the  other  end,  with 
another  thermometer  bulb  inserted  as  before.  The  third  ther- 
mometer is  placed  between  the  two.  On  heating  the  outer  tube 
by  means  of  a  Bunsen  burner,  so  that  the  central  thermometer 
indicates  about  125°,  the  temperature  of  the  unoiled  waste  ball 
will  be  about  100°.  That  of  the  other  rises  in  proportion  as  the 
oil  oxidises  more  rapidly.  E.  H.  Richards  reports  that  this 
arrangement  gives  most  valuable  results  as  regards  gauging  the 
degree  of  safety  of  lubricating  oils,  &c.  ;  for  instance,  the  per- 
centage of  fatty  oil  which  may  be  safely  mixed  with  mineral  oils 
may  be  thus  determined.  Thus  neat's  foot  oil  and  best  lard  oil 
may  be  added  to  the  extent  of  50-60  per  cent.,  whilst  not  more 
than  25  per  cent,  of  cotton  seed  oil  is  permissible. 

Film-test. — If  a  film  of  oil  be  freely  exposed  to  the  air,  so  that 
heating  to  any  considerable  extent  is  impracticable,  the  effect  of 
the  oxidation  is  gradually  to  inspissate  the  oil,  and  finally  to  con- 
vert it  into  a  varnish-like  product;  a  test  of  the  quality  of  a  given 
sample  of  drying  oil  is  based  upon  this,  a  glass  plate  being 
coated  on  one  side  with  a  film  of  oil,  after  the  fashion  of  a  photo- 
grapher's collodion  plate,  and  then  kept  in  a  steam  bath  for 
some  hours,  preferably  side  by  side  with  another  plate  similarly 
coated  with  oil  of  standard  quality ;  the  relative  length  of  time 
requisite  before  the  film  ceases  to  be  "  tacky,"  being  converted 
into  a  dry  varnish,  serves  as  a  measure  of  its  drying  quality. 
Thus,  whilst  a  good  sample  of  linseed  oil  is  completely  solidified 
in  some  twelve  hours,  non-drying  oils  like  arachis  and  olive  oils 
are  scarcely  thickened  at  all ;  whilst  cotton  seed  oil  and  similar 
substances  possessing  only  a  certain  degree  of  drying  power  are 
intermediate.  In  this  respect  the  order  in  which  oils  are 
arranged  by  means  of  this  test  is  sensibly  the  same  as  that  in 
which  they  are  arranged  by  means  of  the  iodine  absorption 
reaction  (Chap,  vm.) 

Livache's  Test. — Livache  finds  that  the  rate  of  absorption  of 
oxygen  is  much  quickened  if  finely  divided  metallic  lead  is 
mixed  with  the  oil  to  be  examined ;  comparative  tests  are  readily 
made  by  placing  on  a  watchglass  about  a  gramme  of  lead  *  in  a 
thin  layer,  and  then  dropping  on  to  it  a  few  decigrammes  (not 
more  than  6  or  7)  of  oil  in  small  drops,  scattered  over  different 
portions  of  the  lead,  so  as  not  to  run  into  one  another.  The 
whole  is  then  weighed  and  allowed  to  stand  at  the  ordinary 
temperature.  Drying  oils  begin  to  increase  measurably  in 
weight  in  less  than  twenty-four  hours,  and  cease  to  gain  weight 

*  Precipitated  from  lead  acetate  solution,  and  rapidly  washed  with  water, 
alcohol,  and  ether  in  succession,  and  finally  dried  in  vacuo.  According  to 
Hiibl,  precipitated  copper  is  preferable  to  lead. 


134 


OILS,    FATS,    WAX  MS,    ETC. 


after  three  to  six  days,  whilst  oils  possessing  little  or  no  drying 
qualities  do  not  increase  at  all  for  several  days.  Similar  remarks 
apply  to  the  fatty  acids  isolated  from  the  oils.  Thus  the  follow- 
ing figures  were  obtained  : — 


Percentage  Increment  in  Weight 

. 

Of  Oil  after 

Of  Fatty  Acids 

2  Days. 

7  Days. 

8  Days, 

Linseed  oil,  . 

14-3 

11-0 

Nut  oil, 

7-9 

.. 

6-0 

Poppy  oil, 

0-8 

.. 

3-7 

Cotton  seed  oil, 

5-9 

0-8 

Beech  mast  oil, 

4-3 

2-6 

Colza  oil, 

Nil. 

2-9 

2-6 

Arachis  oil,   . 

Nil. 

1-8 

1-3 

llape  oil, 

Nil. 

2-9 

0-9 

Olive  oil, 

Nil. 

1-7                   0-7 

Sesame'  oil,    . 

Nil. 

2-4 

2-0 

Bach,*  following  Freseiiius,  tests  the  oxygen- absorbing  power 
of  oils  by  heating  in  a  closed  tube  containing  oxygen,  and  noting 
the  bulk  of  gas  absorbed.  The  presence  of  excess  of  oxygen  after 
the  experiment  must  be  proved  by  means  of  a  glowing  splinter 
of  wood.  This  test  is  more  particularly  useful  in  the  valuation 
of  certain  kinds  of  lubricating  oils. 


CHEMICAL  CHANGES  OCCURRING  DURING 
DRYING  OF  OILS. 

The  nature  of  the  chemical  changes  taking  place  during  the 
complete  atmospheric  oxidation  and  consequent  drying  up  of  a 
drying  oil  has  been  the  subject  of  various  investigations ;  but  it 
can  hardly  be  said  that  the  matter  is  yet  settled  beyond  dispute. 
The  earlier  researches  on  linseed  and  other  drying  oils  by 
Mulder  and  others  led  to  the  conclusion  that  the  chief  consti- 
tuent of  drying  oils,  giving  them  their  peculiar  properties,  was 
linolin,  the  glyceride  of  linolic  acid,  regarded  as  C16H28O9,  and 
then  termed  linoleic  acid.  During  drying  this  glyceride  was 
supposed  to  become  hydrolysed  or  otherwise  broken  up, 
losing  its  glyceridic  character,  and  forming  oxylinoleic  acid, 
C16Ho6O5 .  2H.2O,  by  oxidation ;  a  neutral  polymerised  amorphous 
anhydro  derivative,  linoxyn,  C32HS4On,  being  subsequently 
developed  as  the  leading  ingredient  of  the  "  skin  "  formed  as  the 
oil  dries.  Later  researches  have  indicated  that  what  \vas  formerly 

*  Journ.  Soc.  Chem.  Twd.,-1889,  p.  990 ;  from  Chem.  Zeit.,  13,  p.  905. 


CHEMICAL    CHANGES    OCCURRING    DURING    DRYING    OF    OILS.    135 

termed  "linoleic  acid,"  C16H28O2,  is  really  a  mixture  of  three 
acids  of  notably  higher  molecular  weights — viz.,  true  linolic  acid, 
C18H32O2,  related  to  oleic  acid  as  oleic  acid  is  to  stearic ;  and 
two  isomeric  acids  still  less  saturated,  related  to  linolic  acid  in 
the  same  way,  linolenic  and  isolinolenic  acids,  both  represented 
by  C18H30O2.  These  substances  by  gentle  oxidation  yield 
crystallisable  acid  products,  sativic  acid  (tetroxystearic  acid), 
melting  at  173°,  being  formed  from  linolic  acid,  and  linusic  and 
isolinusic  acids  (hexoxystearic  acids),  melting  at  203°  to  205° 
and  173°  to  175°  respectively  (vide  p.  43),  being  produced  from 
the  other  two  acids ;  but  these  crystallisable  ultimate  oxida- 
tion products  are  apparently  not  formed  in  the  "  boiling" 
process  at  all  \  and  even  if  contained  in  the  dried  skins  are 
certainly  not  the  constituents  giving  the  peculiar  physical 
properties  to  these  substances.  Moreover,  the  proportions  of 
oxygen  and  water  requisite  to  be  taken  up  by  linolic  and 
linolenic  glycerides  in  order  to  convert  them  into  free  oxy- 
stearic  acids,  are  greatly  in  excess  of  the  increment  in  weight 
observed  to  take  place  during  the  drying  of  oils  of  this  class 
(p.  134) ;  whilst  the  skins  are  found  to  be  susceptible  of  some 
degree  of  saponification,  furnishing  glycerol.  Hence  it  would 
seem  probable  that  the  essential  constituents  of  dried  skins  are 
a  mixture  of  polymerised  glycerides  (possibly  more  or  less  hydro- 
lysed)  of  acids  derived  from  linolic,  linolenic,  and  isolinolenic 
acids  by  oxidation  processes  not  carried  so  far  as  to  produce  the 
various  oxystearic  acids  obtainable  by  means  of  alkaline  perman- 
ganate.* That  some  of  these  substances  are  of  a  feebly  acid 
•character,  or  at  any  rate  are  capable  of  forming  salts  by  the  action 
of  metallic  oxides,  is  suggested  by  the  well-known  fact  that  the 
•effect  of  basic  matters  like  white  lead  (basic  lead  carbonate)  and 
zinc  white  (chiefly  zinc  oxide)  on  the  paint  produced  by  their 
admixture  with  drying  oils  is  different  in  many  respects  from 
that  of  neutral  pigments  like  lead  sulphate  and  sulphate  of 
barium ;  in  practice  these  latter  are  found  to  be  far  less  suitable 
for  the  production  of  firm  adherent  coats  that  will  stand  ordinary 
wear  and  tear,  which  is  usually  considered  to  be  due  to  the 
absence  of  the  metallic  salts  contained .  in  white  lead  and  zinc 
white  paints,  formed  by  the  neutralisation  of  acids  developed  by 
oxidation,  or  possibly  by  the  saponification  of  glycerides. 

The  drying  qualities  of  an  oil  appear  to  be  the  more  marked 
the  greater  the  proportion  of  linolenic  and  isolinolenic  acids  is 

*Fahrion  (Zeitsch.  /.  angew.  Ckem.,  1891,  p.  540;  1892,  p.  171)  finds 
that  the  acids  formed  on  saponification  of  boiled  linseed  oil  where  partial 
•oxidation  has  taken  place  are  not  wholly  soluble  in  light  petroleum  spirit, 
whereas  the  fatty  acids  of  unoxidised  oil  are  readily  soluble  therein ;  from 
0'6  to  31 '0  of  such  insoluble  acids  were  found  in  different  samples  of  oil. 
The  proportion  present  appears  to  be  the  greater  the  more  marked  the 
decrement  in  "iodine  absorbing  power"  produced  by  the  oxidation  process. 
These  "  oxyacids  "  readily  dissolve  both  in  alcohol  and  in  ether. 


136 


OILS,    FATS,    WAXES,    ETC. 


present.  Hazura  and  Griissner  deduced  the  following  percentages 
from  the  relative  proportions  in  which  the  oxystearic  acids  were 
produced  on  oxidising  the  liquid  fatty  acids  of  linseed,  hemp  seed, 
nut,  poppy  seed,  and  cotton  seed  oils,  the  solid  acids  being  pre- 
viously separated  by  conversion  into  lead  salts  and  treatment 
with  ether  (p.  112). 


Linolenic 
Acid. 

Isolinolenic 
Acid. 

Linolic 
Acid. 

Oleic  Acid. 

Linseed  oil,    . 

15 

65 

15 

5 

Hemp  seed  oil, 

15 

70 

15 

Nut  oil, 

13 

80 

7 

Poppy  seed  oil, 

5 

65 

30 

Cotton  seed  oil, 

60 

40 

Bauer  and  Hazura  regard  the  drying  of  oils  as  being  mainly 
due  to  the  linolenic  and  isolinolenic  acids,  which,  by  taking  up 
oxygen,  become  converted  into  the  "  oxylinoleic  acid  ''  of  Mulder, 
which  they  regard  as  C18H30O7.  For  the  most  part,  however,  the 
glyceridic  character  of  the  product  is  not  destroyed  during  the 
oxidation,  so  that,  instead  of  free  acid,  a  neutral  body  results, 
substantially  the  "linoxyn"  of  Mulder,  but  termed  by  them 
hydroxylinolein.  Small  quantities  of  free  fatty  acids  are,  however, 
developed  by  the  decomposition  of  .the  glycerides  of  the  solid 
fatty  acids  present  (myricin,  palmitin,  ttc.) ;  the  glycerol  of  these 
glycerides  being  converted  into  carbon  dioxide  and  other  volatile 
products. 

According  to  experiments  by  Cloez,*  the  effect  produced  by 
prolonged  exposure  to  air  of  a  drying  oil  is  not  quite  so  simple 
as  wTould  appear  from  the  above.  The  following  figures  were 
obtained  with  linseed  and  poppy  seed  oils,  the  final  increment  in 
weight  being  a  little  more  than  7  per  cent,  in  each  case  after 
eighteen  months  : — 

LINSEED  OIL. 


Before  Exposure. 

After  Oxidation. 

Percentage 
Composition. 

Calculated  per  100 
Parts  of  Linseed  Oil 
originally  used. 

Carbon, 
Hydrogen,  . 
Oxygen,      . 

77-57 
11-33 
11-10 

67-55 
9-88 
25-57 

72-30 
10-57 
24-16 

100-00 

100-00 

107-03 

Bulletin  Soc.  Chimique  de  Paris,  1865,  hi.,  p.  49. 


POUTET'S  ELAIDIN  REACTION — NITROUS  ACID  TEST. 
POPPY  SEED  OIL. 


137 


Before  Exposure. 

After  Oxidation. 

Percentage 
Composition. 

Calculated  per  100 
Parts  of  Linseed  Oil 
originally  used. 

Carbon,       .         .         . 

77-50 

66-68 

71-38 

Hydrogen,  . 
Oxygen, 

11-40 
11-10 

9-94 
23  -38 

10-64 
25-03 

100-00 

100-00 

107-05 

The  original  oils  thus  had  a  composition  closely  akin  to  that  of  a 
triglyceride  of  an  acid  of  formula  C18H32O2  (p.  33),  requiring 
carbon  77"90,  hydrogen  11  "16,  oxygen  10*94;  during  oxidation, 
from  TV  to  TTT  of  the  carbon  disappeared  and  not  far  from  the 
same  proportion  of  hydrogen.  Even  if  the  whole  of  the  glyceridic 
part  of  the  oil  had  been  oxidised  to  volatile  products,  only  Jg-  of 
the  carbon  would  have  disappeared  ;  so  that,  obviously,  carbon 
dioxide,  or  acetic  acid,  &c.,  must  have  been  formed  at  the 
expense  of  the  fatty  acids  present,  indicating  a  more  deep-seated 
oxidation  change  than  the  simple  absorption  of  oxygen,  con- 
verting the  glycerides  of  linolenic  and  isolinolenic  acids  into 
hydroxylinolein. 

With  castor  oil  Cloez  found  the  gain  in  weight  after  eighteen 
months  was  much  less  marked  (2*68  per  cent.) ;  whilst  only  a, 
practically  inappreciable  amount  (0*4  per  cent.)  of  the  original 
carbon  had  disappeared.  Intermediate  results  were  obtained 
with  a  semi-drying  oil,  sesame  oil,  the  gain  in  weight  in  eighteen 
months  being  4-83  per  cent.,  and  the  loss  of  carbon  about  ^  of 
the  original  amount. 


POUTET'S   ELAIDIN   REACTION— NITROUS 
ACID   TEST. 

Oils  containing  unsaturated  acid  glycerides,  more  especially 
olein  and  its  homologues,  or  ricinolein,  often  undergo  a  marked 
change,  when  treated  with  nitrous  acid,  becoming  more  or 
less  solidified  without  alteration  of  composition.  Gaseous, 
nitrous  anhydride  (fumes  from  nitric  acid  heated  with  starch 
or  arsenious  anhydride)  will  produce  the  reaction,  or  agitation 
with  substance  containing  nitrous  acid  dissolved — e.g.,  red  nitric 
acid,  solution  of  a  nitrite  recently  acidified,  copper  or  mercury 
recently  dissolved  in  nitric  acid,  or  even  nitric  acid  warmed 
until  it  begins  to  act  on  the  oil.  Of  these  the  liquid  originally 


138 


OILS,    FATS,    WAXES,    ETC. 


described  by  Poutet,  obtained  by  dissolving  12  parts  by  weight 
of  mercury  in  15  of  cold  nitric  acid  (sp.  gr.  1'35),  is  the  most 
convenient ;  *  2  c.c.  of  the  fresh  deep  green  liquid,  and  50  of  oil 
are  shaken  together  in  a  bottle  at  intervals  for  about  two  hours, 
at  the  end  of  which  time  the  action  is  nearly  complete,  although 
the  product  usually  becomes  stiffer  or  harder  on  standing  twenty- 
four  hours.  Olive  oil  of  good  quality  thus  treated  gives  a 
bright  yellow  extremely  hard  "elaidin;"  arachis  and  lard  oils 
yield  products  little  inferior  in  stiffness ;  mustard,  rape,  sesame, 
sunflower,  cotton  seed,  and  other  oils  give  softer  products,  vary- 
ing in  consistency  from  a  stiff  buttery  mass  to  a  mixture  of 
pasty  product  with  still  fluid  substance ;  whilst  linseed  and 
other  drying  oils  are  comparatively  little  affected. 

A.  H.  Allen  classifies  the  more  important  fixed  oils  as  follows, 
in  accordance  with  the  physical  character  of  the  product : — 


Solid  Hard  Mass. 

Buttery  Mass. 

Pasty  or  Buttery  Mass 
separating 
from  a  Fluid  'Portion. 

Liquid  Products. 

Olive  oil. 

Bottlenose  oil. 

Rape  oil. 

Linseed  oil. 

Almond  oil. 

Mustard  oil. 

Mustard  oil. 

Hempseed  oil. 

Arachis  oil. 

Neat's  foot  oil  \ 

Sesame  oil. 

Walnut  oil. 

Lard  oil. 

Arachis  oil       [  Some- 

Cotton  seed  oil. 

Sperm  oil. 

Sperm  oil         /  times. 

Sunflower  seed  oil. 

Neat's  foot  oil 
(sometimes). 

Rape  oil           J 

Niger  seed  oil. 
Cod  liver  oil. 

Whale  oil. 

Porpoise  oil. 

In  certain  cases  (more  especially  with  olive  oil)  the  nature 
and  consistency  of  the  elaidin  formed  on  treatment  with  nitrous 
acid  affords  a  useful  means  of  detecting  the  presence  of  adulter- 
ations with  oils  of  different  character.  In  all  such  cases,  the 
most  satisfactory  results  are  obtained  when  the  oil  examined  is 
tested  side  by  side  in  the  same  way  with  samples  of  oil  of 
standard  purity,  and  of  the  same  mixed  with  known  proportions 
of  other  oils.f 

The  free  fatty  acids  obtained  by  saponifying  oils  and  decom- 
posing the  resulting  soaps  with  a  mineral  acid,  are  affected  by 
nitrous  acid  in  similar  fashion.  Attempts  have  been  made  to 

*  Archbutt  (Journ.  Soc.  Chem.  IncL,  1886,  p.  303)  dissolves  18  grammes 
of  mercury  in  15 '6  c.c.  of  nitric  acid,  sp.  gr.  1'42  (22'2  grammes  of  acid), 
and  uses  1  part  of  the  resulting  green  fluid  to  12  of  oil  (by  weight). 

t  There  is  often  great  difficulty  experienced  in  obtaining  absolutely  pure 
samples  of  oil  for  use  as  standards.  In  many  cases  it  is  only  possible  to 
obtain  such  standard  substances  by  actual  expression  of  hand-picked  seeds, 
&c.,  in  the  laboratory,  and  subsequently  refining  the  product;  but  this  is 
not  readily  practicable,  unless  a  plentiful  supply  of  pure  seed  is  to  hand, 
as  well  as  a  good  form  of  small  experimental  or  laboratory  press. 


NITRIC    ACID    TEST. 


139 


utilise  for  candle-making  and  other  purposes  the  polymerised 
solid  acids  of  higher  melting  point  thus  formed ;  but,  hitherto, 
various  practical  difficulties  have  stood  in  the  way  of  utilising 
the  products  effectively. 

Legler's  Consistency  Tester. — Legler  has  constructed  a 
simple  form  of  apparatus  by  means  of  which  comparative  tests 
can  be  made  of  the  degree  of  consistence  of  the 
elaiclin.  mass  produced  when  any  given  oil  sample 
is  treated  with  nitrous  acid.  It  consists  of  piece  of 
glass  tubing  narrowed  at  one  end  (Fig.  30) ;  through 
the  tube  passes  a  glass  rod  supported  by  means  of 
a  spiral  spring,  and  furnished  with  a  horizontal  disc 
on  the  top,  so  that  by  placing  weights  on  the  disc 
the  end  of  the  rod  is  depressed  to  an  extent  pro- 
portionate to  the  weight  added.  The  outer  tube  is 
held  vertically  by  a  suitable  clamp  holder,  so 
adjusted  that  the  bluntly  pointed  end  of  the  rod 
just  rests  on  the  surface  of  the  elaidin  to  be  tested. 
The  measurement  is  made  by  placing  a  given 
weight  on  the  disc  and  noting  how  far  the  rod 
sinks  into  the  elaidin  in  a  given  time  (e.g.,  a 
minute),  by  reading  off  the  level  on  a  scale  the  zero 
point  of  which  is  level  with  the  top  of  the  outer 
tube  when  the  disc  is  unweighted.  The  elaidin 
samples  are  best  prepared  by  mixing  together 
10  c.c.  of  oil,  10  c.c.  of  nitric  acid  of  25  per  cent., 
and  1  grin,  of  copper  wire  or  turnings,  and  allowing 
to  stand  twenty-four  hours;  the  mass  is  fused  by 
dipping  the  containing  vessel  in  warm  water  so  as 
to  bring  about  complete  separation  of  elaidin  and 
watery  fluid,  and  the  former  removed  and  allowed 
to  solidify.  To  obtain  comparable  results,  a  uni- 
form method  of  manipulating  should  be  adopted, 
the  samples  tested  being  examined  side  by  side 
with  others  similarly  prepared  from  genuine  oils  or 
known  mixtures. 

Exposure  of  olive  oil  to  sunlight  greatly  diminishes 
the  solidity  of  the  elaidin  formed  from  it ;  the  nature         j?ig.  30. 
of  the  change  brought  about  is  uncertain  ;  probably 
oxidation  takes  place  with  formation  of  oxyolein  (or  possibly 
linolin),  as  the  insolated  oil  develops  more  heat  by  the  action  of 
sulphuric  acid  than  the  original  oil  kept  in  darkness  (vide  p.  131). 

Nitric  Acid  Test. — When  fixed  oils  are  brought  into  contact 
with  nitric  acid  a  complex  effect  is  often  produced ;  oxidation  of 
a  part  of  the  oil  by  the  acid  is  brought  about  with  the  evolution 
of  lower  oxides  of  nitrogen,  which  convert  the  olein  constituent 
of  the  oil  into  elaidin.  In  some  cases,  characteristic  colours  are 
produced  with  oils  of  pure  nature,  so  that  a  comparison  of  the 


140 


OILS,    FATS,    WAXES,    ETC. 


substance  tested  with  a  pure  standard  substance,  or  with  a  known 
mixture,  enables  deductions  to  be  drawn  as  to  the  nature  of  the 
admixture  or  adulteration  present.  This  kind  of  test  is  more 
especially  useful  in  the  case  of  olive  oil ;  thus,  when  pure 
olive  oil  is  treated  with  one-ninth  its  volume  of  nitric  acid 
of  sp.  gr.  1-42,  the  mixture  being  gently  warmed  in  a  capacious 
dish  until  the  acid  begins  to  act  pretty  vigorously,  and  then 
stirred  briskly  (the  source  of  heat  being  removed)  until  no 
further  action  is  visible,  a  pale  yellow  solid  mass  is  formed 
after  standing  an  hour  or  two ;  whereas,  if  cotton  seed  oil  be 
present,  a  much  darker  tinted  product  is  formed,  which  does 
not  set  so  readily  j  and  similarly  when  various  other  oils  are 
present. 

A.  H.  Allen  gives  the  following  table,*  indicating  the  different 
tests  developed  when  several  of  the  commonest  oils  are  tested  in 
the  following  ways  : — 

a.  Nauchcorne's  Test,  as   extended  by  Stoddart. — Agitate  to- 


Oil. 

a. 

b. 

! 

Olive  oil, 

Colourless  or  tran- 

Colourless, yel- 

Broad bright 

sient  yellow. 

lowish,  or 

bluish  green 

greenish. 

zone. 

Almond  oil,     . 

Nearly  colourless, 

Colourless  or 

Narrow  bright 

changing  to  solid 
white  mass. 

slightly  greenish. 

green  zone  ;  oil  \ 
flocculent  or 

opaque. 

Arachis  oil,     . 

... 

Reddish. 

... 

Peach  kernel  oil, 

... 

Immediate  red 

liniment. 

Rape  oil, 

Red  or  orange. 

Reddish  or  orange. 

Sesame  oil, 

Yellowish  or 

j 

orange. 

Cotton  seed  oil, 

Red  or  orange. 

Reddish  or  orange. 

Brown  red, 

greenish  below. 

Niger  seed  oil, 

Red  or  orange. 

Brown  or 

... 

brownish  red. 

Linseed  oil, 

Red  or  orange. 

Red  or  orange. 

Green  zone,  oil 

red. 

Poppy  seed  oil, 

... 

Reddish. 

Dark  green  zone, 

oil  pink. 

Hemp  seed  oil, 

... 

Brownish  red. 

Castor  oil, 

Transient  yellow. 

Yellowish  or 

... 

orange. 

Lard  oil, 

Colourless  or  tran- 

... 

... 

sient  yellow. 

Whale  oil,       . 

Dark  red. 

... 

Seal  oil,  . 

Dark  red. 

... 

Cod  liver  oil,  . 

... 

. 

Brown  red. 

Rosin  oil, 

Reddish  brown. 

. 

... 

Mineral  oil,     . 

Dark  red. 

• 

... 

Commercial  Organic  Analysis,  vol.  ii.,  p.  61. 


ZINC    CHLORIDE    REACTION    AND    COLOUR    TEST.  141 

gether  from  3  to  5  measures  of  the  oil  with  1  of  nitric  acid  of 
specific  gravity  \'3'2.  Heat  the  tube  for  five  minutes  in  boiling 
water  ;  then  take  it  out  and  allow  it  to  stand.  Observe  the 
colour  of  the  oil  from  time  to  time  for  one  and  a-half  hours. 

b.  Massies    Test. — Agitate    3    measures   of  the   oil   for   two 
minutes   with   1   measure   of  colourless   nitric   acid   of  specific 
gravity  1-40.     Observe  the  colour  of  the  oil  after  separation. 

c.  Glassner's    Test. — Pour   the    oil    cautiously    into   an    equal 
measure  of  red  fuming  nitric  acid,  and  observe  the  colour  of  the 
oil  and  of  the  zone  which  forms  between  the  oil  and  the  acid 
liquid. 


ZINC  CHLORIDE  REACTION  AND  COLOUR  TEST. 

Some  oils,  more  especially  castor  oil,  when  heated  in  contact 
with  a  highly  concentrated  solution  of  zinc  chloride,  become 
converted  into  a  gristly  mass,  which,  on  treatment  with  water 
to  dissolve  out  the  zinc  chloride,  more  or  less  breaks  up  into 
cartilaginous  or  fibrous  portions,  which  swell  up  largely  to  white 
masses  closely  resembling  rasped  cartilage,  the  oil  being  com- 
pletely solidified  by  the  process.  Apparently,  the  chemical  action 
consists  chiefly  of  polymerisation,  somewhat  after  the  fashion  of 
the  elaidin  reaction,  possibly  accompanied  by  dehydration;  by 
long  continued  boiling  of  the  product  with  alkalies,  partial 
saponification  is  effected,  glycerol  being  set  free. 

To  produce  the  most  gristly  product,  the  following  process 
may  be  followed:* — Zinc  chloride  solution  is  boiled  down  until 
the  boiling  temperature  rises  to  about  175°  C.  or  upwards,  the 
composition  of  the  fluid  then  being  close  to  that  indicated  by 
the  formula,  ZnCl2,  H2O,  or  slightly  less  hydrated.  Three  parts 
of  this  fluid  by  weight,  and  one  of  castor  oil  are  then  well 
intermixed  together  at  a  temperature  of  125°  or  thereabouts; 
the  oil  speedily, becomes  more  viscid,  and  then  coagulates  to  a 
leathery  mass  resembling  bullock's  liver,  but  tougher,  mostly 
separating  from  the  zinc  chloride  in  so  doing.  This  mass  is  then 
chopped  up,  soaked  in  water  till  disintegrated  to  a  mass  some- 
what resembling  coarsely  scraped  horseradish,  drained  from  zinc 
chloride  solution  and  washed,  when  it  is  in  suitable  condition  for 
use  in  the  manufacture  of  india-rubber  substitutes,  insulating 
coatings  for  electric  leads,  &c. 

By  using  weaker  zinc  chloride,  or  smaller  proportions,  or 
lower  temperatures,  the  action  can  be  controlled  and  stopped 
before  going  quite  so  far,  so  as  to  produce  substances  of  less 
cartilaginous  and  more  plastic  character ;  or  other  oils,  less 

*  Patent  specification,  C580,  1886,  Hun-head  and  Alder  Wright. 


142 


OILS,    FATS,    WAXES,    ETC. 


readily  acted  upon,  may  be  mixed  with  the  castor  oil ;  or  resin, 
Kauri  gum,  and  similar  substances  may  be  similarly  admixed. 

Colour  Test. — When  zinc  chloride  solution  of  somewhat 
lesser  strength  (of  thick  syrupy  consistence  when  cold)  is  mixed 
with  certain  oils,  colours  are  developed.  Muter  gives  the 
following  table,  founded  on  the  results  of  Chateau  :* — 

To  10  drops  of  the  oil  in  a  porcelain  capsule,  add  5  drops  of 
syrupy  zinc  chloride,  and  stir. 


White  or  scarcely  affected. 

Yellow,  Red,  or  Brown. 

Green  or  Blue  Shades. 

Poppy. 
Nut. 
Almond  (hot  pressed). 
Gingelly. 
Cokernut. 

Linseed  (English),  ) 
Rape,                        '  yellow. 
Groundnut,              } 
Castor,  rose  yellow. 
Beech,  flesh  rose. 

Linseed  (foreign), 
bluish  green. 

S£}«~- 

Gold  of  pleasure 

Neat's  foot. 
Lard. 
Horse  bone. 
Sperm. 
Whale  (sometimes 
pale  violet  tinge). 
Cod  liver  (cold). 

Whale,  yellow  brown. 
Fish,  orange  yellow. 
Seal,  red  brown. 

green. 
Almond,  milky  with 
green  tinge. 

Cod  liver  (hot), 
green. 

Action  of  Zinc  Chloride  on  Oleic  Acid. — Zinc  chloride, 
when  heated  with  oleic  acid,  converts  it  into  a  solid  isomeride 
closely  resembling  elaidic  acid,  but  not  identical  therewith  ;  thus, 
when  oleic  acid,  mixed  with  10  per  cent,  of  its  weight  of  zinc 
chloride,  is  heated  to  180°  to  185°  (but  not  exceeding  195°)  for 
some  time,  the  transformation  is  so  far  complete  that  a  sample 
taken  out  and  treated  with  hot  dilute  hydrochloric  acid  yields  a 
layer  of  fatty  acids,  solidifying  on  cooling.  By  diluting  with 
water  and  subjecting  to  distillation  with  superheated  steam  (or 
under  diminished  pressure),  a  buttery  mass  is  obtained  which, 
on  pressing  (first  cold  and  then  hot),  finally  yields  a  hard 
crystallisable  material  of  melting  point  41°  to  42°,  suitable  for 
making  certain  kinds  of  candles  not  requiring  fatty  matter  of 
high  fusing  point  (Schmidt's  process).  Benedikt  obtained  the 
following  results  on  analysis  of  the  products  thus  formed  :  — f 

A.  Crude  product  obtained  by  boiling  the  heated  mass  with 
diluted  hydrochloric  acid. 

B.  Product  of  distillation  under  diminished  pressure. 

C.  Solid  mass,  after  pressing  until  the  melting  point  rises  to 
41°  to  42°. 


*  Spon's  Encyclopaedia  of  Arts  and  Manufactures,  ii.,  p.  1473. 
•\-Journ.  Soc.  Chem.  2nd.,  1890,  p.  658;  from  Movatsh.,  1890,  ii.,  p.  71. 


ACTION    OF    SULPHURIC   ACID    ON    OILS    AND    FATS. 


143 


A. 

B. 

c. 

Liquid  anhydride, 

8 

Stearolactoiie,   . 

28 

31-0 

75-8 

Oxystearic  acid, 

17 

... 

Oleic  and  isoleic  acids, 

40 

43-3 

15-7* 

Saturated  fatty  acids, 

7 

12-1 

8-5 

Unsaponifiable  matters,     . 

13-6 

... 

100 

100-0 

100-0 

The  " unsaponifiable  matters"  contained  in  B  were  mainly 
liquid  hydrocarbons  of  the  olefine  series  (carbon  =  84*1,  hydro- 
gen =  13-7,  oxygen  =  2-2). 

It  would  appear  that  the  general  character  of  the  main  action 
is  that  zinc  chloride  directly  combines  with  the  oleic  acid,  and 
that  the  resulting  compound  (or,  possibly,  pair  of  isomeric  com- 
pounds) is  partly  decomposed  again  into  oleic  and  isoleic  acids, 
and  partly  hydrolysed  with  formation  of  oxystearic  acids,  more 
especially  the  7  acid,  which  then  loses  the  elements  of  water, 
forming  stearolactone  (vide  p.  39) ;  the  hydrolytic  action  pro- 
bably being  as  follows  : — 


Oleic  Acid. 

Cl8H3402 

Compound. 
Cl8H3402,  ZnCl2 


Zinc  Chloride. 

ZnCl2 


H20 


Compound  of  Zinc  Chloride 
aud  Oleic  Acid. 

Cl8H3402,ZnCl2. 

Oxystearic  Acid. 
ZnCl2         +          C18H3603. 


In  all  probability,  similar  reactions  occur  when  glycerides 
containing  olein  are  saponified  by  means  of  sulphuric  acid,  the 
yield  of  liquid  oleic  acid  in  the  products  finally  obtained  by 
distillation  with  superheated  steam  being  very  small. 


ACTION  OF  SULPHURIC  ACID   ON  OILS  AND  FATS, 
TURKEY  RED  OILS. 

When  sulphuric  acid  is  added  to  a  fixed  oil  or  fat,  various 
kinds  of  effects  are  produced  in  different  cases;  in  many  instances 
distinctive  colours  are  developed,  due  not  so  much  to  the  action 
of  the  acid  on  the  glycerides  themselves  as  to  that  upon  other 
bodies  accompanying  them  in  small  proportion;  this  is  especially 
marked  in  the  case  of  certain  fish  liver  oils  where  biliary  con- 
stituents are  present  (vide  infra).  In  other  cases  action  occurs 
between  the  acid  and  the  glyceride,  producing  more  or  less 

*  Isoleic  acid  only. 


144 


OILS,    FATS,    WAXES,    ETC. 


marked  heat  development,  sometimes  leading  to  charring  and 
destruction,  sometimes  to  less  deep-seated  changes  of  a  definite 
character.  Thus,  when  oils  mainly  consisting  of  olein  are 
cautiously  mixed  with  sulphuric  acid  hydrolysis  ensues,  the 
resulting  glycerol  being  more  or  less  converted  into  glycero- 
sulpkuric  acid,  much  as  ordinary  alcohol  is  into  ethylsulphuric 
acid. 


Sulphuric  Acid. 

on  ,JOH 
S°2\OH 


Ethylsulphuric  Acid. 

=      S02 


Iphuric  Acii 

O .  C2H5 
OH 


Sulphuric  Acid.  Glycerosulphuric  Acid. 

SO,  /RS      =      S02(O.C3Hi(OH)2 


Water. 

H20 

Water. 
H20 


Alcohol. 

C2H5 .  OH 

Glycerol. 

(  OH 

C3H5     OH 
(  OH 

Simultaneously  the  oleic  acid  is  acted  upon,  direct  combination 
taking  place  between  the  two  acids  *  with  the  formation  of 
oxystearosulpliuric  acid. 

*  According  to  M tiller- Jacobs,   the  product   thus   formed   contains  the 
elements  of  a  molecule  of  waterless,  Cl8H3405S  instead  of  C^HaflOfjS  ;  and 

(  SO     OFT 
is  represented  by  him  as  a  sort  of  sulphonic  acid,  Cl7H32  j  nr/'  QTJ»  breaking 

tip  on  hydrolysis  with  the  formation  of  oxystearic  acid,  C^Ks.-!  nn  ntr' 

(  C\~\3  L  ^-'^'•^-'•£1 

oxyoleic  acid,  C^HsoJpQ    QTT  being  also  formed,  probably  by  a  secondary 

action.  Geitel  considers  that  a  mixed  glyceride  is  formed,  part  of  the  three 
oleic  radicles  being  modified  by  direct  addition  of  sulphuric  acid  thereto  so 
as  to  form  a  glyceride  where  the  radicle  of  oxystearosulphuric  acid  partly 
replaces  the  oleic  radicle,  saponification  of  the  glyceride  not  taking  place, 
at  any  rate,  at  first. 

Liechti  and  Suida  also  consider  a  mixed  glyceride  to  be  the  first  product, 


containin 
thus— 


2C3H5 


simultaneously  the  radicles  of  sulphuric  and  oxystearic  acids, 


Triolein. 


O.C18H330 
O.C18H3,0 
O.C8HS30 


Water.          Sulphuric  Acid. 


vy.^H^ 


4H20 


S02(OH)2     = 


Oleic  Acid. 
4C]8H3402 


Oxystearosulphuric 
Diglyceride. 

(  O.C18H3502 
OH 

°}S02 

OH 
O.C18H,,02 


Simultaneously,  they  regard  an  analogous  mixed  diglyceride  as  being 
formed,  containing  the  radicle  of  oxyoleic  acid  (C]8H3302)  instead  of  that 
of  oxystearic  acid  (Cl8H3.502).  this  substance  being  produced  in  virtue  of  an 
oxidising  action  exerted  by  the  sulphuric  acid,  whereby  S02  is  evolved. 

Inasmuch  as  practically  no  glycerol  is  obtainable  from  Turkey  red  oil  by 
saponification  (beyond  what  is  due  to  undecomposed  original  oil  present 
therein),  whilst  free  oleic  acid  gives  products  similar  to  those  prepared  from 
olive  oil  (the  more  free  acid  contained  in  the  oil  the  better  it  is  suited  for 
the  purpose),  it  is  obvious  that  these  mixed  glycerides,  even  if  formed 
under  special  conditions,  are  at  any  rate  not  the  main  constituents  of  the 
commercial  products. 


TURKEY   RED    OILS.  145 

Oleic  Acid.  Sulphuric  Acid.  Oxystearosulphuric  Acid.  Water. 

C17H33.COOH  +  S02°      =  S02°Cl'H34-CO-OH  +  H20 


This  product,  being  a  saturated  compound,  does  not  combine 
with  iodine  like  the  original  oleic  acid  (Benedikt  and  Ulzer)  ; 
under  the  influence  of  hydrolysing  agents  it  breaks  up  into 
oxystearic  and  sulphuric  acids,  thus  *  — 

Oxystearosulphuric  Acid.  Water.        Sulphuric  Acid.  Oxystearic  Acid. 

Qn    f  0  .  C17H34  .  CO  .  OH    ,    w  n         Qn   J  OH    ,    r    „    J  OH 
S°2  +  H20    =  S02  +  C17H34 


10H 

Products  containing  more  or  less  Oxystearosulphuric  acid  and 
the  oxystearic  acid  thence  formed  by  hydrolysis,  together  with 
unchanged  olein,  and  some  free  oleic  acid  (also  whatever  solid 
fatty  glycerides  were  originally  present  in  the  oil  employed  and 
the  products  of  the  action  of  sulphuric  acid  thereon)  are  manu- 
factured from  olive,  cotton  seed,  and  similar  oils  chiefly  consisting 
of  olein,  for  use  in  dyeing  and  calico  printing,  especially  in  the 
production  of  "  Turkey  red,"  whence  the  name  "  Turkey  red 
oils  "  applied  to  these  products  ;  the  free  acidity  is  usually 
partially  or  wholly  neutralised  by  cautious  addition  of  ammonia 
or  other  alkali  to  the  oil  after  washing  with  brine  or  water. 

Another  variety  of  Turkey  red  oil,  considerably  superior  for 
some  special  applications,  is  produced  when  castor  oil  is 
employed  instead  of  olein-containing  oils.  According  to  the 
generally  received  view,  the  chief  action  of  the  sulphuric  acid  is 
precisely  analogous  to  that  on  ordinary  alcohol  ;  the  glyceride  is 
hydrolysed  into  glycerol  and  ricinoleic  acid,  the  former  being 
more  or  less  converted  into  glycerosulphuric  acid,  as  above  ;  the 
ricinoleic  acid  reacts  on  the  sulphuric  acid  in  a  parallel  way, 
forming  ricinoleosulphuric  acid,  thus  — 

Riciuoleic  Acid.  Sulphuric  Acid.       Water.  Ricinoleosulphuric  Acid. 

r    w      f°H  i.   ^n    /OFI        w  n  j.  r    w     /O.S02.OH 

CirH^o  -^  CQ    QH    -      =>U2  j  QR  =  LlrH32  j  C0    OH 

the  resulting  product  differing  from  that  formed  from  oleic  acid  in 
that  it  contains  H9  less,  and  is,  therefore,  an  "unsaturated"  com- 
pound, capable  of  taking  up  iodine  or  bromine  in  the  same  manner 
as  the  original  ricinoleic  acid  itself  (Benedikt  and  Ulzer).  Accord- 
ingly, castor  Turkey  red  oil  is  capable  of  taking  up  oxygen,  and 
generally  of  behaving  in  ways  not  observed  in  the  case  of  olive 
Turkey  red  oil  ;  which  circumstance  renders  it  more  suitable  for 
certain  particular  applications  in  reference  to  dyestuffs,  &c. 

*  The  effect  of  sulphxiric  acid  in  decomposing  fatty  glycerides,  together 
with  the  hydrolysing  action  of  water  on  the  product,  is  utilised  in  the 
preparation  of  caudle  material  ;  a  larger  yield  of  solid  matter  is  thus 
obtained  than  by  the  ordinary  saponification  processes,  on  account  of  the 
conversion  of  liquid  oleic  acid  into  solid  substances.  According  to  Geitel, 
y-oxi/fstearic  acid  (p.  39)  is  usually  produced  (inter  alia)  by  the  hydrolysis 
of  the  compouud  of  oleic  acid  with  sulphuric  acid,  which  immediately  splits 
up  into  water  and  stearolactone. 

10 


14  G  OILS,    FATS,    WAXES,    ETC. 

A  somewhat  different  view  of  the  action  of  sulphuric  acid  on 
castor  oil  has  been  lately  put  forth  by  Scheurer  Kestner"*  as  the 
result  of  his  investigations.  After  the  glyceride  has  been  hydro- 
lysed,  he  finds  that  part  of  the  resulting  ricinoleic  acid  becomes 
"polymerised"  (or  more  accurately,  dehydrated  and  "con- 
densed "),  so  as  to  form  a  more  complex  molecule  of  diricinoleic 
acid,  which  is  then  acted  upon  by  sulphuric  acid  so  as  to  form 
diricinoleosulphuric  acid  ;  the  reactions  may  be  written  thus  — 

Ricinoleic  Acid  (2  molecules).  Diriciuoleic  Acid. 

TT     JOH  „      (OH 


TT 

17H 


o    OH  1732^CO, 

H  0    TT      $°     / 

32     co  .  OH  C"H«*     CO  .OH 


Diricinoleic  Acid.  Sulphuric  Acid.  Diricinoleosulphuric  Acid. 

TT     JOH  r    TT     JO.  SO.,.  OH 

17^32    I  rv\  \  ^irn32  T  Cf)  }     ~ 

=  0 


22  2 

C17H     - 


S02(OH)2   =   H20 
|  co   OH  1732  -|  co  .  oil 

Obviously  the  diricinoleosulphuric  acid  thus  formed  is  "un- 
saturated,"  and  is,  therefore,  capable  of  taking  up  two  halogen 
atoms  for  each  C1S  present.  More  or  less  of  the  diricinoleic  acid 
escapes  conversion  into  diricinoleosulphuric  acid;  so  that  in 
addition  to  unaltered  castor  oil,  &c.,  the  resulting  Turkey  red 
oil  consists  of  a  mixture  of  diricinoleic  acid,  and  diricinoleo- 
sulphuric acid,  together  with  some  amount  of  ricinoleic  acid  that 
has  escaped  condensation  to  diricinoleic  acid,  and  of  ricinoleo- 
sulphuric  acid  formed  by  the  direct  action  of  sulphuric  acid  upon 
it.  The  non-  sulphurised  fatty  acids  tend  to  the  development  of 
blue  shades  with  alizarin,  whilst  the  ricinoleosulphuric  acids  tend 
to  produce  yellow  shades. 

Diricinoleosulphuric  acid  is  hydrolysed  by  caustic  alkali,  the 
soda  or  potash  salts  of  diricinoleic  and  sulphuric  acids  being 
formed  if  the  action  take  place  at  temperatures  below  80°  C.:  but 
by  prolonged  boiling  with  alkali,  or  treatment  therewith  under 
pressure,  water  is  taken  up  and  ordinary  ricinoleic  acid  regenerated 
by  reversal  of  the  two  reactions  above  indicated.  In  just  the 
same  way  ricinoleosulphuric  acid  becomes  hydrolysed  into  sul- 
phuric and  ricinoleic  acids,  the  action  taking  place  extremely 
readily  in  presence  of  hydrochloric  acid.  In  presence  of  sulphuric 
acid,  Turkey  red  oil  is  apt  to  be  yet  further  decomposed  on 
heating,  osnanthic  acid,  inter  alia,  being  formed:  hence,  in  the 
preparation  of  the  oil  care  must  be  taken  that  overheating  does  not 
take  place  }  and  similarly  in  washing  out  the  excess  of  sulphuric 
acid,  (tc.,  with  brine  (to  avoid  solution  of  the  soluble  compound 
sulphuric  acids  formed),  otherwise  hydrochloric  acid  is  apt  to 
be  formed  and  considerable  loss  of  soluble  acids  occasioned  by 

*  Comptes  Rendus,    112,    pp.    153  and   395;    also,    Journ.    Soc.    Chem. 
Ind.,  1891,  p.  471. 


.ACTION    OF    SULPHURIC    ACID    ON    OILS    AND    FATS. 


147 


hydrolysis  ;  sodium  sulphate  is  accordingly  preferable  to  sodium 
chloride  as  diminishing  this  tendency  to  loss. 
According  to  Juillard*  acids  still  more 
highly  "polymerised"  than  diricinoleic  acid 
are  formed  when  sulphuric  acid  acts  on 
castor  oil,  three,  four,  and  five  molecules  of 
riciiioleic  acid  becoming  condensed  and  dehy- 
drated, with  the  formation  of  triricinoleic, 
tetraricinoleic,  and  pentarwinoleic  acids  re- 
spectively. He  regards  the  first  action  as 
giving  rise,  by  partial  hydrolysis  and  etherify- 
ing  action  jointly,  to  the  product, 

0  .  CO  .  C17H,., .  0  .  SO.SH 
OH 
(0.  CO.  C,7H32.  OH 

which  then  loses  a  molecule  of  water  forming 
an  anhydride,  termed  by  him  dicinolein  sul- 
phuric anhydride. 

(0.  CO.  C17H,,.  0.  SO., 
C3HS}0— 

(0.  CO.  C17H32.OH 

This  reacts  slowly  with  riciiioleic  acid  and 
sulphuric  acids  forming  the  various  poly- 
ricinoleic  acids  above  mentioned,  and  the 
polyricinoleo  sulphuric  acids  thence  derived  ; 
so  that  commercial  castor  Turkey  red  oils  are 
highly  complex  mixtures. 

Maumene's  Sulphuric  Acid  Thermal 
Test. — A  considerable  development  of  heat 
usually  attends  the  chemical  action  brought 
about  011  mixing  together  a  fixed  oil  and 
strong  sulphuric  acid ;  by  making  compara- 
tive observations  in  precisely  the  same  way 
with  standard  pure  oils,  or  known  mixtures, 
and  the  substance  to  be  tested,  useful  infor- 
mation can  often  be  obtained  as  to  the 
character,  and  to  some  extent  the  amount, 
of  foreign  admixture  present.  It  is,  how-  pjg  3^ 

ever,  impossible  to  lay  down  any  precise 
figures  universally  applicable  in  such  cases,  because  the  rate  of 
action,  and  consequently  the  rise  in  temperature,  greatly  de- 
pends on  the  way  in  which  the  intermixture  is  effected,  and 
especially  on  the  strength  of  the  acid  used.  Commercial  oil  of 
vitriol  varies  considerably  in  its  strength,  sometimes  containing 

*  Journ.  ,S'oc.  Chem.  Ind.,  1892,  p.  355;  from  Bulletin  Soc.  Chim.,  Paris, 
1891,  6,  p.  6,38. 


148  OILS,    FATS,    WAXES,    ETC. 

96  to  97  per  cent,  of  true  sulphuric  acid,  H0S04,  sometimes  only 
90  to  91  per  cent.,  or  even  less.  If  the  liquid  be  boiled  in  a 
retort  under  ordinary  atmospheric  pressure  until  about  a  quarter 
has  distilled  over,  the  residue  when  cool  enough  may  be  bottled 
and  kept  for  use,  being  acid  of  about  98  per  cent,  strength.* 

Eig  31  represents  a  form  of  apparatus  for  applying  the  test ;  a 
graduated  cylinder,  B,  is  provided  with  an  india-rubber  stopper, 
through  which  passes  the  stem  of  a  thermometer,  A,  so  graduated 
that  the  divisions  are  all  above  the  stopper ;  a  short  piece  of 
quill  tubing,  0,  also  passes  through  the  stopper,  serving  as  a 
vent.  25  c.c.  of  oil  are  run  into  the  cylinder,  and  then  5  c.c.  of 
sulphuric  acid,  the  latter  by  means  of  a  pipette  applied  to  the 
side  of  the  cylinder,  so  that  the  acid  falls  to  the  bottom  without 
mixing  with  the  oil.  The  stopper  and  thermometer  being  in- 
serted and  the  temperature  taken,  the  end  of  C  is  closed  by  the 
finger,  and  the  whole  shaken  up  for  a  few  seconds  ;  C  is  imme- 
diately unclosed,  and  the  thermometer  watched,  so  as  to  note 
the  highest  point  to  which  it  rises,  and  hence  the  range  through 
which  the  chemical  action  has  heated  the  mass. 

In  order  to  diminish  errors  due  to  radiation  and  convection, 
a  small  beaker  may  be  used,  jacketted  outside  with  a  somewhat 
larger  one,  the  interspace  being  filled  with  cotton  wool  or  fibrous 
asbestos.  50  grammes  of  oil  and  10  c.c.  of  sulphuric  acid  are 
convenient  quantities,  the  two  being  at  the  same  temperature  to 
start  with  ;  the  acid  is  run  in  slowly  from  a  pipette,  the  mixture 
being  vigorously  stirred  with  a  thermometer,  and  about  a 
minute  being  allowed  for  the  addition ;  the  temperature  gra- 
dually rises  to  a  maximum  as  the  stirring  is  continued,  remains 
nearly  constant  for  a  short  time,  and  then  falls  again,  the  precise 
amount  of  rise  depending,  to  some  extent,  on  the  way  in  which 
the  admixture  is  made.  When  drying  oils  are  examined, 
Maumene  recommends  dilution  with  olive  oil,  so  that  the 
temperature  should  not  rise  so  high  as  to  char  the  mixture 
(paraffin  hydrocarbons  are  regarded  by  other  experimenters  as 
preferable) ;  further,  he  recommends  that  trials  should  be  made 
with  different  proportions  of  oil  and  acid,  e.r/.,f 

50  grammes  oil  to  18  c.c.  acid. 
50        „  „         36        „ 

100        „  „         18 

*  Pure  "monohydrated"  sulphuric  acid,  H2S04,  cannot  be  obtained  by 
evaporation;  when  a  strength  of  98  to  98 '5  per  cent,  is  attained,  the 
temperature  rises  to  a  point  where  the  substance  dissociates  into  water 
and  sulphur  trioxide,  the  latter  passing  off  at  the  same  rate  as  the  water 
vapour,  so  that  acid  of  that  strength  distils  unchanged.  Pure  H2S04  may 
be  obtained  by  adding  the  calculated  amount  of  SOjj  to  oil  of  vitriol, 
strengthened  by  evaporation  as  far  as  possible  ;  or  by  chilling  the  acid,  and 
draining  off  the  unfrozen  mother  liquor  from  the  crystals  of  H2S04  that 
form.  When  heated,  S03  is  evolved,  and  acid  of  about  98  per  cent,  left, 
which  then  distils  unchanged. 

•\ComptesRendus,  xxxv.,  p.  572;  also/owr/?.  Soc.  Chem.  Ind.,  1SSC,  p.  361. 


ACTION    OF    SULPHURIC    ACID    ON    OILS    AND    FATS. 


149 


The  following  table  exhibits  some  of  Maumene's  results, 
together  with  those  subsequently  obtained  by  others ;  numerous 
other  analogous  values  have  been  recorded,  exhibiting  more  or 
less  marked  differences  according  to  the  particular  mode  of 
manipulation  adopted  : — 


Maumene". 

Allen. 

Baynes. 

Archbutt. 

Degrees. 

Degrees. 

Degrees. 

Degrees. 

Menhaden  oil,  . 

126 

123  to  128 

Cod  liver  oil,    . 

102  to  103 

113 

lie 

Linseed  oil, 

103 

104  to  111 

104  to  124 

Walnut  oil, 

101 

... 

... 

Hemp  seed  oil, 

98 

Seal  oil,    . 

92 

... 

Whale  oil,  northern, 

... 

91 

Whale  oil,  southern, 

... 

92 

Poppy  seed  oil, 

74 

... 

86  to  88 

Cotton  seed  oil,  crude, 

... 

67  to  69 

... 

70 

Cotton  seed  oil,  refined, 

... 

74  to  75 

77 

75  to  76 

Arachis  oil, 

67 

47  to  60 

Beechnut  oil,    . 

65 

... 

Rape  and  colza  oils, 

57  to  58 

51  to  60 

60  to  92 

55  to  64 

Almond  oil, 

52  to  54 

... 

35 

Horse  foot  oil,  . 

51 

... 

... 

Tallow  oil, 

41  to  44 

... 

... 

Lard  oil,  . 

41 

... 

... 

Sperm  oil, 

... 

45  to  47 

... 

51 

Bottlenose  oil,  . 

... 

41  to  47 

42 

Olive  oil,  . 

42 

41  to  43 

40 

4i  to  45 

Castor  oil, 

47 

65 

46 

Neat's  foot  oil, 

... 

... 

... 

43 

Oleic  acid, 

... 

38-5 

37-5 

Obviously,  an  admixture  of  rape  oil  with  linseed  oil,  or  vice 
versa,  may  be  characterised  with  some  degree  of  precision  (the 
former  yielding  a  value  of  little  more  than  half  that  given  by 
the  latter),  when  the  suspected  sample  is  examined  side  by  side 
with  samples  of  known  purity  mixed  in  known  proportions  (e.g., 
2  to  1,  equal  proportions,  or  1  to  2,  and  so  on).  Similarly  with 
olive  oil  admixed  with  arachis  oil,  or  with  cotton  seed  oil ;  or 
sperm  oil  mixed  with  fish  oil.  According  to  Archbutt,  olive  oil 
exposed  to  sunlight  for  some  time  develops  considerably  more 
heat  with  sulphuric  acid  than  the  same  oil  kept  in  the  dark ; 
52°-o  rise  of  temperature  being  noted  by  him  instead  of  41°'5. 

A  yet  greater  difference  was  observed  by  Ballantyne  in  the 
case  of  olive  oil  exposed  to  light  for  six  months,  and  agitated 
daily  so  as  to  promote  aerial  oxidation  (67°  instead  of  44°), 
analogous  differences  being  also  observed  with  several  other 
kinds  of  oils  similarly  treated  (p.  131). 

Specific  Temperature  Reaction. — In  order  to  render  the 
thermal  test  practically  independent  of  variations  in  the  strength 


150 


OILS,    FATS,    WAXES,    ETC. 


of  the  sulphuric  acid  used,  Thomson  and  Ballantyne*  make  simul- 
taneously a  comparative  valuation  with  water,  and  calculate  the 
ratio  between  the  heat  developed  with  the  oil  examined  and 
that  with  the  water ;  the  resulting  ratio  they  term  the  specific, 
temperature  reaction.  Thus  the  following  figures  were  obtained 
with  acid  of  different  strengths,  showing  a  considerably  closer 
concordance  between  the  "  specific  temperature  reactions  "  than 
between  the  uncorrected  values  first  obtained  with  the  different 
strengths  of  acids  ;  of  course,  exact  agreement  is  not  to  be  ex- 
pected, as  the  heat  development  in  the  case  of  an  oil  is  not 
brought  about  solely  by  the  mere  physical  admixture,  but  is  also 
influenced  by  the  chemical  changes  set  up,  which  necessarily  are 
apt  to  vary  with  the  strength  of  the  acid  : — 


Sulphuric  Acid  of  954 

Sulphuric  Acid  of  96  8 

Sulphuric  Acid  of  99 

per  cent.  H2S04. 

per  cent.  H2S04. 

per  cent.  H2S04. 

Substance  Used. 

Rise  in 
Tempera- 
ture. 

Specific 
Tempera- 
ture 
Reaction. 

;     Rise  in 
Tempera- 
ture. 

Specific 
Tempera-, 
tu  re 
Reaction. 

Rise  in 
Tempera- 
ture. 

Specific 
Tempera- 
ture 
Reaction. 

Degrees  C. 

Degrees  C. 

Degrees  C. 

Water, 

38-6 

100 

41-4 

100 

46-5 

100 

( 

36-5 

95 

39-4             95 

44-8            96 

Olive  oil,     < 

34-0 

88 

38-1 

92              44-2            95 

\ 

... 

39-0 

94 

43-8 

94 

Rape  oil,  . 

49-0 

1'27 

... 

58-0 

124 

Castor  oil, 

34-0 

88            37-0 

89 

Linseed  oil, 

104-5 

270 

125-2 

269 

The  following  values  for  the  specific  temperature  reactions  of 
various  kinds  of  oils  were  thus  determined  : — 


Nature  of  Oil. 

Specific  Temperature  Reaction 
Water  =  100. 

Olive  oil  (13  kinds  examined), 
Cotton  seed  oil  (crude),  .... 
,,                (refined  —  2  kinds),  . 
Rape  oil  (5  kinds),  ..... 
Arachis  oil  (commercial), 
(refined),        .... 
Linseed  oil  (4  kinds),       .... 
Castor  oil  (2  kinds),          .... 
Southern  sperm  oil,          .... 
Arctic  sperm  oil  (bottlenose), 
Whale  oil  (pale),      
Seal  oil  (4  kinds),    

89  to  95 
163 
169  to  170 
125  to  144 
137 
105 
270  to  349  ' 
89  to  92 
100 
93 
157 
212  to  225 

Cod  oil  (3  kinds),     
Menhaden  oil,          ..... 

243  to  272 
306 

*  Journ.  Soc.  Chem.  2nd,,  1891,  p.  233. 


ACTION    OF    SULPHURIC   ACID    ON    OILS    AND    FATS. 


151 


F.  Jean  uses  a  special  form  of  apparatus,  termed  by  him  a 
<f  Thermeleometer,"  "*  for  the  determination  of  the  heat  evolved 
in  mixing  sulphuric  acid  and  oils  (Fig.  32).  A  is  a  small  vessel 
40  mm.  diameter  and  60  high,  enclosed  in  a  felt-lined  case,  E  ; 
this  holds  the  oil  (15  c.c.)  B  is  a  U-shaped 
tube,  holding  5  c.c.  of  sulphuric  acid  (at  65° 
B),  furnished  with  a  hollow  glass  stopper,  to 
which  is  attached  a  piece  of  rubber  tubing, 
Jl.V.;  by  blowing  through  the  tubing  the 
acid  is  forced  out  of  the  reservoir,  B,  and 
runs  down  on  to  the  oil  through  the  turned- 
over  narrow  exit  pipe.  T  is  a  thermometer 
clamped  to  B.  To  use  the  instrument  the 
acid  is  introduced  into  B  by  removing  the 
stopper,  and  the  oil  run  into  A  up  to  a 
given  mark  representing  15  c.c.;  the  oil  is 
heated  up  to  40°  to  50°  C.,  the  acid-holder 
placed  in  it,  and  the  whole  allowed  to  cool 
with  occasional  stirring  to  30° ;  A  is  then 
placed  in  the  casing,  E,  and  the  acid  blown 
over  into  the  oil,  B,  the  attached  ther- 
mometer being  used  as  a  stirrer,  and  the 
highest  temperature  attained  read  off. 

Colour  Reactions  produced   by  Sul-  Fig.  32. 

phuric  Acid. — The  table  on  p.  152  is  given 

by  A.  H.  Allen,  exhibiting  the  effect  of  placing  a  drop  or-  two 
of  sulphuric  acid  in  the  centre  of  about  twenty  drops  of  oil, 
observing  the  colour  before  and  after  stirring,  f 

Some  oils  char  more  or  less  with  sulphuric  acid ;  in  such 
cases,  one  drop  of  the  oil  may  be  dissolved  in  twenty  of  carbon 
disulphide,  and  one  drop  of  sulphuric  acid  added.  Whale  oil 
thus  treated  gives  a  fine  violet  coloration,  quickly  changing  to 
brown,  whereas,  with  sulphuric  acid  alone,  a  mere  red  or  reddish 
brown  colour,  changing  to  brown  or  black,  is  obtained. 

Miscellaneous  Colour  Reactions. — Various  other  reagents 
have  been  proposed  as  colour  tests  for  oils — e.g.,  stannic  chloride, 
barium  polysulphide,  phosphoric  acid,  mercuric  nitrate  (alone  or 
with  subsequent  addition  of  sulphuric  acid),  aqua  regia,  caustic 
soda,  &c.  For  the  most  part,  these  give  but  little  more  informa- 
tion than  is  afforded  by  the  colour  tests  above  described,  except 
in  some  few  special  cases ;  thus,  linseed  oil  boiled  with  caustic 
soda  gives  a  yellowish  emulsion,  but  if  fish  oils  are  present,  a 

*Journ.  Soc.  Chem.  Ind.,  1890,  p.  113;  from  Pharm.  Chem.,  1889,  xx., 
p.  337. 

t  Various  modifications  of  the  colour  test  proposed  in  1861  by  Chateau 
(by  mixing  oils  with  sulphuric  acid)  have  been  suggested  by  different 
observers ;  in  some  cases  the  test  produced  is  subject  to  considerable 
variation,  according  to  the  amount  of  acid  used  relatively  to  the  oil,  and 
its  strength. 


152 


OILS,    FATS,    WAXES,    ETC. 


reddish  colour  results.  A  solution  of  silver  nitrate  in  alcohol 
(2  parts  nitrate  to  12  of  water,  88  parts  alcohol  added  to  the 
liquid),  when  heated  with  about  five  times  its  volume  of  oil,  is 


OiL 

Before  Stirring. 

After  Stirring. 

Vegetable  Oils. 
Olive  oil,    . 

Yellow,  green,  or  pale  \ 
brown.                         / 

Light  brown  or  olive 
green. 

Almond  oil, 

Colourless  or  yellow.    - 

Dark  yellow,  olive,  or 
brown. 

Arachis  oil,         .         -| 

Greyish      yellow      to  \ 
orange.                        j 

Greenish    or     reddish 
brown. 

Rape  oil  (crude), 

Green     with      brown  ) 
riiijjs.                             \ 

Bright  green,  turning 
brownish. 

(refined),       | 

Yellow    with    red    or  j 
brown  rings.                \ 

Brown. 

Mustard  oil, 

Bark    yellow    withl 
orange  streaks.           / 

Reddish  brown. 

Cotton  seed  oil  (crude), 
,  ,             (refined), 

Very  bright  red. 
Reddish  brown. 

Dark  red,  nearly  black. 
Dark  reddish  brown. 

Xiger  seed  oil,    .         -I 

Yellow    with     brown  1 
clot.                              J 

Reddish    or     greenish 
brown. 

( 

Yellow    spot     with  ) 

Poppy  seed  oil,  . 

orange     streaks     or  > 

Olive  or  reddish  brown. 

( 

rings.                            ) 

Linseed  oil  (raw), 

Hard  brown  or  green-  1 
ish  brown  clot.             J 

Mottled,  dark  brown. 

(boiled),     . 

Hard  brown  clot. 

Mottled,  dark  brown. 

Castor  oil,  . 

Yellow  to  pale  brown,  j 

Nearly    colourless    or 
pale  brown. 

Animal  Oils. 

I 

Greenish     yellow      or  } 

Lard  oil,     .         .          < 

brownish  with  brown  > 

Mottled  or  dirty  brown. 

( 

streaks.                         \ 

Tallow  oil, 

Yellow  spot  with  pink  \ 
streaks.                        J 

Orange  red. 

Whale  oil,  .         .          j 

Red,  turning  violet. 

Brownish  red,  turning 
brown  or  black. 

Seal  oil,      .         .          j 

Orange  spot  with  pur-  \ 
pie  streaks.                   J 

Bright    red,    changing 
to  mottled  brown. 

Cod  liver  oil,      .          j 

Dark    red    spot    with  \ 
purple  streaks.            / 

Purple,     changing    to 
dark  brown. 

Sperm  oil,  . 

Pure  brown  spot  with  \ 
faint  yellow  ring.        j 

Purple,     changing     to 
reddish       or      dark 
brown. 

Hydrocarbon  Oils. 

Petroleum  lubricating  ~| 
oil,                             J 

Brown. 

Dark  brown  with  blue 
fluorescence. 

Shale  lubricating  oil,  . 

Dark  reddish  brown,     -j 

Reddish    brown    with 
blue  fluorescence. 

Rosin  oil  (brown), 

Bright       mahogany  ) 
brown.                           \ 

Dark  brown  with  pur- 
ple fluorescence. 

(pale),  . 

Mahogany  brown. 

Red-brown  with  purple 
fluorescence. 

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154  OILS,    FATS,    WAXES,    ETC. 

more  or  less  reduced  in  many  cases,  developing  a  brownish  red, 
brown,  or  black  colour ;  *  cotton  seed,  bitter  almond,  hemp, 
linseed,  neat's  foot,  and  colza  oils  show  the  reaction  most 
markedly,  especially  the  first  named. 

The  table  on  p.  153  (by  Schadler)  exhibits  synoptically  the 
results  of  various  reagents  on  several  of  the  more  commonly  oc- 
curring oils,  &c. ;  the  test  with  hydrochloric  acid  and  sugar  is  made 
by  mixing  equal  quantities  of  the  oil  to  be  examined  and  hydro- 
chloric acid  of  specific  gravity  1-125  (about  1  c.c.  of  each),  adding 
a  gramme  of  cane  sugar,  and  shaking  vigorously  for  some  time. 

SULPHUR    CHLORIDE    REACTION. 
VULCANISED   OILS. 

The  use  of  sulphur  chloride  in  "  vulcanising  "  india-rubber  "  is 
well  known ;  a  somewhat  analogous  change  takes  place  wThen 
this  substance  (preferably  diluted  with  light  petroleum  oil, 
carbon  disulphide,  or  other  suitable  solvent)  is  intermixed  with 
certain  oils,  more  especially  linseed  oil ;  solidification  ensues, 
with  the  result  of  forming  a  more  or  less  leathery  mass,  which  is 
employed  to  some  considerable  extent  in  the  manufacture  of 
insulating  coverings  for  electric  mains  and  leads,  and  similar 
purposes.  During  the  action  considerable  quantities  of  hydro- 
chloric acid  are  evolved,  whilst  the  final  product  contains 
sulphur,  some  of  which  is  in  a  condition  insoluble  in  carbon 
disulphide,  apparently  combined  with  the  oil  constituents ;  so 
that  the  chemical  action  of  sulphur  chloride  appears  to  be  of  a 
far  more  deep-seated  nature  than  that  of  nitrous  acid  (elaidin 
reaction),  where  the  solidification  appears  to  be  due  simply  to 
polymerisation  or  isomeric  re-arrangement  of  atoms.  Although 
no  true  oxidation  takes  place  during  the  .treatment,  the  term 
"oxidised  oil"  is  often  applied  to  this  product  in  the  trade, 
probably  because  the  solidification  brought  about  is  some- 
Avhat  akin  in  appearance  to  that  effected  when  drying  oils 
are  oxidised  by  exposure  to  air,  forming  solid  products. 

Another  kind  of  "vulcanised  oil"  is  obtained  by  mixing 
fiowers  of  sulphur  with  the  oil  to  be  treated,  and  then  applying 
heat,  much  as  in  the  process  of  vulcanising  india-rubber.  In 
some  cases  the  oils  are  previously  partly  saponified.  By  heating 
linseed  oil  to  about  230°  C.,  cooling  to  176°  C.  (350°  F.),  and 
then  stirring  in  sulphur,  an  india-rubber  like  mass  is  finally 
obtained,  useful  in  the  preparation  of  rubber  substitutes.  As 
with  sulphur  chloride,  hydrogen  appears  to  be  removed  during 
the  process,  sulphuretted  hydrogen  freely  escaping;  this  renders 
the  manufacture  an  especially  foetid  one  unless  great  care  be 
taken  to  destroy  the  evil-smelling  vapours  evolved,  by  causing 

*  Cruciferous  oils  containing  sulphur  form  black  silver  sulphide  by  this 
treatment. 


SULPHUR    CHLORIDE    REACTION. 


155 


them  to  pass  through  a  furnace  before  escaping  into  the  factory 
chimney,  or  some  analogous  treatment. 

The  effect  of  chloride  of  sulphur  (diluted  with  carbon  disul- 
phide)  upon  oils  of  various  kinds  is  so  far  different  that  in 
certain  cases  it  may  be  employed  to  discriminate  one  from 
another,  or  to  test  for  admixture ;  as  in  all  other  analogous 
cases,  comparison  of  the  sample  tested  with  genuine  oils,  treated 
side  by  side,  is  necessary  in  order  to  obtain  reliable  results. 
Bruce  Warren  finds  *  that  when  5  grammes  of  oil  are  mixed 
with  2  c.c.  of  carbon  disulphide  and  2  of  a  mixture  of  equal 
volumes  of  carbon  disulphide  and  yellow  sulphur  chloride  (free 
from  dissolved  sulphur)  and  the  whole  heated  on  a  waterbath 
till  action  commences,  the  products  formed  (after  evaporating  off 
carbon  disulphide)  differ  in  weight  and  character  according  to  the 
nature  of  the  oil,  being  partly  soluble  in  carbon  disulphide  and 
partly  insoluble  therein.  Thus  poppy  seed  and  linseed  oils  gave 
the  following  figures  (5  grammes  used  in  each  case)  :— 


Poppy  Seed. 

Linseed. 

Mixture  of  .Equal 
Quantities  of  the  Two. 

; 

Soluble,  . 
Insoluble, 

1-96 
4-50 

0-78 
5-58 

MO 

5-37 

Total, 

6-46 

6-36 

6-47 

C.  A.  Fawsitt  f  employs  sulphur  chloride,  S2C10,  purified  by 
distillation,  in  the  proportion  of  2  c.c.  to  30  grammes  of  oil, 
operating  as  in  the  case  of  Maumene's  sulphuric  acid  test ;  very 
considerable  differences  are  observed  with  different  oils  as 
regards  the  amount  of  heat  evolved,  the  rate  of  its  evolution, 
and  the  formation  or  otherwise  of  hydrochloric  acid  gas  ;  thus, 
the  following  figures  were  obtained,  inter  alia. 


4  c.c.  Sulphur  Chloride  to  30  grins.  Oil. 

Name  of  Oil. 

Gas  Evolution. 

Rise  in 
Temperature. 

Time  in  Rising. 

Rise  per  Minute. 

Degrees  C. 

Minutes. 

Sperm, 

Very  small. 

71 

8 

8-8 

Seal,    . 

None. 

112 

5 

224 

Whale, 

Slight. 

91 

3 

30-2 

Neat's  foot, 

j> 

82 

4 

20-5 

Eape, 

None. 

89 

6 

14-8 

Cotton  seed  , 

Slight. 

93 

6 

15-4 

Linseed, 

Considerable. 

97 

2 

48-7 

Olive, 

Slight. 

94 

4 

23-5 

Cod  liver, 

Abundant. 

103 

3 

34-3 

Palmnut, 

Slight. 

9 

7 

1-4 

Oleic  acid, 

Considerable. 

99 

G 

165 

Stearic  acid,     j  None. 

8 

5 

1-6 

Chemical  News,  1888,  57,  p.  113.      t  Jour  a.  Sec.  Chem.  Ind.,  1888,  p.  552. 


156 


OILS,    FATS,    WAXES,    ETC. 


Name  of  Oil. 

2  c.c.  Sulphur  Chloride  to  30  grms.  Oil. 

Gas  Evolution. 

Rise  in 
Temperature. 

Time  in  Rising. 

Rise  per  Minute. 

Degrees  C. 

Minutes. 

Sperm, 

Very  small. 

37 

16 

2-3 

Seal,   . 

None. 

45 

10 

4-4 

Whale, 

Slight. 

57 

6 

9'4 

Neat's  foot, 

» 

51 

7 

7-3 

Lard,  . 

» 

40 

16 

2-4 

Rape, 

None. 

53 

10 

5-3       ' 

Cotton  seed, 

Slight. 

49 

11 

4-4 

Linseed, 

Considerable. 

57 

5 

11-4 

Olive, 

Slight. 

52 

6 

8-7 

Castor, 

Abundant. 

56 

2 

277 

Cod  liver,   . 

)  9 

55 

4 

13-7 

Palm, 

35 

3 

11  6 

Palmnut,     . 

Slight. 

5 

9 

0-5 

Rosin, 

Abundant. 

31 

'    7 

4-4 

Oleic  acid,  . 

Considerable. 

53 

6 

10-6 

Stearic  acid, 

None. 

5 

7 

07 

It  would  hence  seem  that  the  relative  figures  obtained  with 
a  given  pair  of  oils  often  vary  considerably  according  as  2  or  4 
c.c.  of  sulphur  chloride  are  used ;  so  that  the  value  of  the  test  as 
applied  to  mixtures  is  somewhat  doubtful. 


CHAPTER  VIII. 
QUANTITATIVE   REACTIONS  OF   OILS,  &c. 

A  VARIETY  of  quantitative  chemical  tests  are  in  use  with  the 
object  of  obtaining  information  on  various  points  connected  with 
the  general  chemistry  of  fatty  matters,  so  as  to  afford  evidence 
in  cases  of  suspected  adulteration,  <tc.  Some  of  these  depend  on 
the  occurrence  of  saponification  changes;  others  on  different 
principles.  Amongst  them  may  be  reckoned  the  determination  of 
the  amount  of  unsaponifiable  matter  present  effected,  as  described 
on  p.  119,  and  the  valuation  of  the  amount  of  free  fatty  acids 
present,  not  contained  as  glycerides  (vide  p.  116)  ;  in  addition  to 
these,  the  following  tests  are  also  more  or  less  frequently  em- 
ployed, named  after  the  various  chemists  who  have  proposed 
them : — 

1    Kattstorfer' s  Tes\ — Determination  of  the  amount  of  potash 


KCETTSTORFER'S  TEST.  157 

(KOH,  equivalent  56'1)  requisite  to  saponify  1,000  parts  of  sub- 
stance— i.e.,  the  permillage  of  potash  requisite  for  saponification. 

2.  Heliner's  Test. — Determination  of  the  percentage  of  fatty 
acids  formed,  insoluble  in  hot  water. 

3.  JBeichert's  Test. — Determination  of  the  proportion  of  acids 
formed,  volatile  with  the  steam  of  water  when  distilled  under 
certain  arbitrary  conditions. 

4.  llubl's    Test. — Determination    of  the    quantity    of    iodine 
capable  of  direct  combination  with  100  parts  of  substance. 

5.  Benedikt  and   Ulzer's  Test. — Determination  of  amount   of 
acetic  acid  formed  by  acetylating  substances  containing  alcoholi- 
form  hydroxyl,  and  saponifying  the  product ;  expressed  as  per- 
millage of  potash,   equivalent  to  the    acetic   acid  thus    formed, 
reckoned  per  1,000  parts  of  acetylated  product. 

6.  ZeiseUs  Test. — Determination   of  amount    of    silver  iodide 
formed  from  the  alkyl  iodide  (methyl,  ethyl,  &c.,  iodide),  evolved 
on   heating    with   hydriodic   acid ;    expressed  as   the  weight  of 
methyl  (CH3  =  15),  equivalent  to  the  silver  iodide  thus  formed 
from  1,000  parts  of  substance. 


KCETTSTOKFER'S  TEST—  TOTAL  ACID  NUMBER. 

Owing  to  the  different  molecular  weights  of  the  various  fatty 
acids  contained  in  glycerides  and  compound  ethers,  it  necessarily 
results  that  equal  weights  of  different  substances  are  chemically 
equivalent  to  different  amounts  of  alkali  —  i.e.,  that  the  quanti- 
ties of  caustic  potash,  for  example,  requisite  to  bring  about  the 
saponification  reaction 

Glyreride.  Caustic  Potash.         Glycero!.  Potash  Soap. 

+    3KOH   =   C5°3    +   3KOX 


vary  with  the  nature  of  X  when  equal  weights  of  fatty  matter 
are  used  throughout.  The  greater  the  molecular  weight  of  X, 
the  less  potash  will  be  requisite  to  saponify  a  given  weight. 
The  quantitv  of  caustic  potash  requisite  for  saponification,  being 
a  measure  of  the  molecular  weight  of  the  fatty  glycerides,  &c., 
present,  has  been  shown  by  Kcettstorfer  to  afford  in  many 
cases  a  useful  means  of  checking  the  nature  and  purity  of  the 
oil,  &c.,  examined.  The  weight  of  potash  (KOH  —  56'1)  thus 
consumed  by  1,000  parts  of  substance  (milligrammes  of  potash 
per  gramme)  is  accordingly  known  as  the  "  Kcettstorfer  number," 
{  Verseifungszahl)  ;  or  otherwise  as  the  "  total  acid  potash  per- 
millage "  or  "  total  acid  number"  of  the  oil,  &c.,  examined.  The 
determination  of  this  value  is  effected  in  somewhat  the  same 
fashion  as  that  of  the  "free  acid  number"  above  described 


158 


OILS,    FATS,    WAXES,    ETC. 


(p.  116),  by  saponifying  the  oil  with  an  excess*  of  alcoholic  potash, 
and  back-titrating  the  unneutralised  surplus  ;  in  this  way  the 
potash  consumed  represents  not  only  the  free  fatty  acid  present 
but  also  that  liberated  during  saponification  —  i.e.,  the  total  fatty 
acids  present  —  whence  the  name. 

Knowing  the  total  acid  number  (Koettstorfer  number),  K  of 
a  given  substance,  the  mean  equivalent  weight  of  the  substance 
is  readily  calculated  by  the  proportion 


56-1 


1,000 


The  value   of  x  thus  deduced  is   generally  referred    to    as  the- 
"  saponification  equivalent  "  of  the  body  in  question. 


Substance. 

Total  Acid  Number,  or 
Koettstorfer  Number 
Chief  Sources.                 (Permillage    of   Potash 
required  for 
Saponification,    &c.). 

Saponification 
Equivalent. 

Glycerides. 

Tributydn, 

Butter  fat, 

557-3 

100-7 

Trivalerin, 

Porpoise,  dolphin, 

and  whale  oils, 

489-2 

114-7 

Trilaurin,  . 

Cokernut  and 

palmnut  oils, 

263-8 

2127 

Tripalmitin, 

Palm  oil,  lard, 

208-8 

268-7 

Tristearin, 

Tallow,  lard,  cacao 

butter, 

189-1 

296-7 

Triolein,     . 

Olive  and  almond 

oils, 

190-4 

294-7 

Trierucin, 

Colza  and  rape  oils. 

160-0                      350-7 

Trilinolin, 

Linseed,  hemp,  and 

walnut  oils,                           191-7                       2927 

Triricinolein, 

Castor  oil, 

180-6                     310-7 

Compound  Ethers. 

Cetyl  palmitate, 

Spermaceti, 

116-9                     480 

Myricyl  palmitate, 

Beeswax, 

83-0                     676 

Ceryl  cerotate,  . 

Chinese  wax, 

71-2                     788 

Dodecatyl  oleate, 

Sperm  oil, 

1247                      450 

Dodecatyl 

doeglate, 

Bottlenose  oil,                         120-9                     464 

The  foregoing  table  represents  the  total  acid  numbers  and 
saponification  equivalents  of  various  triglycerides  and  compound 
ethers  of  frequent  occurrence ;  in  the  case  of  glycerides  the 
molecular  weight  is  three  times  the  saponification  equivalent, 
whilst  with  compound  ethers  of  monohydric  alcohols  it  is 
identical  therewith. 

Classification  of  Oils,  &c.,  by  Means  of  their  Saponifica- 
tion Equivalents. — The  table  on  p.  159  has  been  arranged  by 

*  Unless  a  more  or  less  considerable  excess  be  used,  it  is  very  difficult  to 
ensure  complete  saponification. 


SAPONIFICATION    EQUIVALENTS. 


159 


Percentage  of  KOH  re-          Saponification 
quired  lor  Saponification.          Equivalent. 

;  A.  OLEINES— 

Lard  oil, 

19-1    to  19  6         |\ 

Olive  oil, 

18-93  to  19  6           I 

Sweet  almond  oil, 

19-47  to  19  61         1 

Arachis  oil, 

19  ^lo^9'66      }  285to29G 

Tea  oil,  .... 

Sesame"  oil, 

19-00  to  19-24         1 

Cotton  seed  oil, 

19-10  to  19-66 

B.  RAPE  OIL  CLASS— 

/ 

Colza  oil, 

17-08  to  17-90 

Rape  oil, 
Mustard  seed  oil, 

17-02  to  17-64 
17-4 

313  to  330 

Cabbage  seed  oil, 

17-52 

C.  VEGETABLE  DRYING  OILS— 

Linseed  oil, 
Poppy  seed  oil,  . 

18-74  to  19-52 
19-28  to  19-46 

\ 

Hemp  seed  oil,  . 

19-31 

>    286  to  300 

Walnut  oil,        . 

19-60 

L 

Niger  seed  oil,  . 

189    to  19-1 

) 

D.  MARINE  OLEINES  — 

Cod  liver  oil,     . 

18-51  to  21-32 

1* 

Menhaden  oil,  . 

19-20 

Pilchard  oil, 

18-6    to  18-75 

Seal  oil,. 

189    to  19-6 

250  to  303 

Southern  whale  oil, 

19-31 

Northern  whale  oil, 

18-85  to  22-44 

Porpoise  oil, 

21-60  to  21-88         J 

E.  BUTTER  CLASS— 

Butter  fat, 

22-15  to  23-24              241  to  253 

Cokernut  oil,     . 
Palmnut  oil, 

24-62  to  26-84 
22-00  to  24-76 

}    209  to  255 

F.  STEARINES,  &c.— 

Lard,     .... 

19-20  to  19-65 

\ 

Tallow,  .... 

19-32  to  19-80 

1 

Dripping, 

19-65  to  19-70 

Butterine, 
Goose  fat, 

19-35  to  19'65 
19-26 

V  277  to  294 

Bone  fat, 

19  '06  to  19  71 

Palm  oil, 

19-C3  to  20-25 

1 

Cacao  butter,    . 

19-98 

/ 

G.  FLUID  WAXES— 

Sperm  oil,          .             .             . 

12  34  to  14  74 

380  to  454 

Bottlenose  oil,  .            .            . 

12-30  to  13-40 

419  to  456 

H.  SOLID  WAXES— 

Spermaceti, 

12-73  to  13-04 

432  to  441 

Beeswax, 

9-2   to   9-7 

... 

Carnauba  wax,  . 

7-9    to    851 

I.  UNCLASSED— 

Shark  liver  oil,  . 

14  00  to  19-76 

284  to  400 

Wool  fat  (suint), 

17-0 

330 

Olive  kernel  oil, 

18-85 

298 

Castor  oil, 

17-6    to  18-15 

309  to  319 

Japanese  wood  oil, 

211 

266 

Japan  wax, 

21-01  to  22-25 

252  to  267 

Myrtle  wax, 

20-57  to  21-17 

265  to  273 

Blown  rape  oil, 

198    to  20  4 

275  to  284 

Colophony, 

170    to  19  3 

290  to  330 

160 


OILS,    FATS,    WAXES,    ETC. 


A.  H.  Allen  *  representing  the  percentages  of  caustic  potash 
required  for  the  saponification  of  most  of  the  usually  occurring 
oils,  &c.,  deduced  by  collecting  together  the  published  results  of 
a  number  of  observers,  some  of  the  values  being  deduced  from 
upwards  of  forty  different  samples. 

Values  but  little  removed  from  these  have  been  subsequently 
collected  and  recorded  by  Benediktf  and  Schadler,|  including 
various  later  valuations  of  the  Koettstofer's  values  of  other  oils 
and  fats  : — 


Name  of  Oil,  &c. 

Schadler. 

Benedikt. 

Apricot  kernel,   .... 

192-193 

192-9 

194-196 

190-1-197 

Almond,  sweet,  .... 

190-192 

187-9-196-1 

Almond,  bitter,  .... 

... 

194-5-196-6 

Butter,         

225-230 

227 

Beeswax  (yellow), 

95-100  > 

97-107 

Bone  oil,      ..... 

190-191 

... 

Cacao  butter,       .... 

198-200 

Cokernut,    ..... 

255-260 

255 

Colza,  

177-178 

175-179 

230-231 

230-5 

Charlock,     

176-177 

Castor,         

201-203 

176-181-5 

Carnauba  wax,    .... 

79 

Cotton  seed,         .... 

194-195 

191-210-5 

Cod  liver,  medicinal,  . 
Cod  liver,  brown, 

175-185 
180-200 

j       171-213-2 

Galam  butter,      .... 

192-193 

... 

Gundschit  (lallemantia), 

184-185 

185-0 

Hemp  seed,          .... 

192-194 

193-1 

Hedge  radish,     .... 

176-177 

174-0 

Japanese  wax,     .... 

222-223 

... 

Linseed  oil,          .... 

190-192 

187  -4-1  95  -2 

Lard,  

195-196 

Malabar  tallow  (piney  tallow),    . 

191-192 

... 

Menhaden,  ..... 

... 

192 

Maize,          ..... 

188-189 

188-1-189-2 

Neat's  foot,          .... 

191-193 

189-191 

189-191 

Nut  (Walnut),    .... 

196-197 

1960 

Olive,  salad,        .... 
Olive,  inferior,    .... 

191-193 

186-188 

|      185-2-196 

Olive  kernel,        .... 

188-189 

188-5 

193-194 

192-8-194-6 

Palm,  

201-202 

Palm  kernel,        .... 

246-248 

257-6 

Pumpkin  seed,     .... 

189-190 

189-5 

*  Commercial  Organic  Analysis,  vol.  ii.,  p.  41,  et  seq.  The  "percentage 
of  caustic  potash  requisite  "  is  obviously  one-tenth  of  the  Kcettstorfer  number, 
or  permillage  of  potash  necessary  for  saponitication. 

t  Analyse  dtr  Fette  und  Wachsarten,  pp.  294  and  317. 

£  Unttrsuchunrjen  der  Fette  Oele  und  Wachsarten,  pp.  134,  135. 


SAPONIPICATION    EQUIVALENTS. 


161 


Name  of  Oil,  &c.                                    Schadler. 

Benedikt. 

143-9 

Pilchard,     
Shark  liver  oil,    .... 
Seal  oil,       .         .         .         .         .              180-195 

Fluid  portion  263'0 
186-187-5 
84-5 
191-196 

Sesame,       192-193 
Sunflower,  193-194 
Spermaceti,          ....                   108 
Sperm  oil,  134 
Suet  (ox  tallow,  beef  tallow),      .               193-195 
Tallow  (sheep),   ....               192-195 
Tacamahac,         ....              199-200 

187-6-192-2 
193 
108-1 
132-2 

Unguadia,  190-192 
Whale,        190-191 

Whale,  bottlenose,      ... 

Woolgrease,         ....              169-170 

1 

190-191 
197-3 
Fluid  portion  290  '0 

Practical  Determination  of  Saponiflcation  Equivalents 
of  Glycerides,  &c.  —  A  known  weight  of  the  substance  to  be 
examined  (conveniently  2  or  3  grammes)  is  accurately  weighed 
up  in  a  flask,  and  25  c.c.  (or  other  suitable  quantity)  of  standard 
alcoholic  potash  added  (approximately  seminormal);  this  should 
be  made  from  alcohol  —  not  methylated  spirit  —  that  has  been  coho- 
bated  with  caustic  potash,  and  distilled  so  as  to  remove  as  far  as 
possible  all  compound  ethers  and  other  impurities  that  might  be 
resinised  by  potash,  or  otherwise  partially  neutralise  alkali  ; 
methylic  alcohol  of  high  purity  may  be  similarly  used,  preferably 
after  the  same  treatment.  The  whole  is  heated  on  a  waterbath 
with  a  reflux  condenser  attached,  and  gently  agitated  at  intervals 
until  complete  solution  has  taken  place  ;  after  a  few  minutes 
more  heating  to  ensure  that  saponification  is  complete,  the  un- 
neutralised  alkali  is  titrated  by  seminormal  standard  acid  (pre- 
ferably hydrochloric),  using  phenolphthalein  as  indicator.  The 
standardising  of  the  alcoholic  potash  in  terms  of  the  acid  is  pre- 
ferably effected  by  heating  25  c.c.  on  the  waterbath,  with  an 
inverted  condenser  attached,  side  by  side  with  the  oil  examined, 
and  subsequently  titrating  ;  the  difference  between  the  acid 
required  in  the  two  cases  thus  directly  represents  the  acid 
equivalent  to  that  formed  by  the  saponification.  If  w  be  the 
weight  in  milligrammes  of  oil  taken,  and  n  the  number  of  c.c.  of 
normal  acid  equivalent  to  the  acid  formed  by  saponification  (i.e.,  if 
2n  c.c.  of  seminormal  acid  be  used,  lOn  of  deciiiormal,  and  so  on), 
then  the  saponification  equivalent  E  is  given  by  the  equation  * 


*1   c.c.  of  "normal"    acid  represents   E  milligrammes  of  fat,  whence 
n  c.c.  of  acid  are  equivalent  to  7iE  milligrammes.     Since  this  quantity  =  w, 


162  OILS,    FATS,    WAXES,    ETC. 

and  the  total  acid  number  (Kcettstorfer  number  =  permillage  of 
potash,  or  tenfold  the  percentage,  requisite  for  saponification)  by 
the  equation 

K  =  —  x  56,100. 

w 

The  determination  of  the  total  acid  number  is  generally  com- 
bined with  that  of  the  free  acid  number  ;  the  weighed  quantity 
of  fat,  <fcc.,  mixed  with  a  little  warm  alcohol,  is  titrated  with 
alcoholic  alkali,  using  phenolphthalein  as  indicator,  so  as  to 
determine  the  free  acid  number  (see  p.  116);  excess  of  alkali  is 
then  added  and  the  determination  of  the  total  acid  number  pro- 
ceeded with.  Thus,  suppose  that  2-501  grammes  (2,501  milli- 
grammes) of  Japanese  wax  contain  sufficient  free  fatty  acid  to 
neutralise  2  '5  c.c.  of  seminormal  alkali  (equal  to  1-25  c.c.  of 
normal  solution)  ;  whilst  after  adding  excess  of  alkali,  saponify- 
ing, and  back-titrating,  19-0  c.c.  of  seminormal  fluid  (equal  to 
9-5  c.c.  normal)  are  neutralised  in  all;  then  the  free  acid  and 

1-25 
total   acid  numbers  are  respectively--—  ,  x  56,100=  2S'04,  and 

9.5 
9          x  56,100  =  213-1  ;  whilst  the  saponification  equivalent  is 

2'SOI  _ 
~W  '3' 

If  A  be  the  free  acid  number,  and  K  the  total  acid  number 
(Koattstorfer  number),  the  quantity  K  -  A  is  a  measure  of  the 
proportion  of  compound  ethers  (esters,  glycerides,  &c.)  present 
in  the  substance  examined,  and  may  be  conveniently  termed  the 
ester  number  (Esterzald*  JEtherzaliT)  }  thus  in  the  above  instance 
the  ester  number  is  263-3  -  28-04  -  235-26.  In  general,  if 
m  c.c.  of  normal  alkali  are  consumed  in  neutralising  the  free 
acid  present  in  iv  milligrammes  of  substance,  and  n  c.c.  in 
neutralising  the  total  acids,  the  value  of  the  ester  number, 
K  -  A,  is  given  by  the  equation 

K  -  A  =  m  x  56,1CO  -  —  x  56,100 
w  w 

=  ^L^X  56,100. 


In  the  case  of  triglycerides,  the  quantity  of  glycerol  theoreti- 
cally obtainable  from  a  given  weight  of  substance   is  readily 

it  results  that  E  =  —  .  On  the  other  hand,  1  c.c.  of  normal  acid  represents 
56*1  milligrammes  of  KOH,  whence  n  c.c.  are  equivalent  to  n  x  56  1  milli- 
grammes. Then  w  :  n  x  56  '1  :  :  1,000  :  K  =  --  x  56,100. 


ESTER    NUMBER.  163 

deduced  from  the  ester  number :  3  x  56*1  parts  of  potash 
neutralised  by  the  acids  liberated  from  the  triglycerides,  represent 
92  parts  of  glycerol  set  free  :  hence,  if  S  is  the  ester  number,  the 

92 

glycerol    produced    is    Y~^Q^J  x  S  =  0-5466  x  S    per    mille,    or 
Ibo'o 

•05466  x  S  per  cent.;  thus,  a  sample  of  groundnut  oil,  yielding 
the  total  acid  number  195-0,  and  the  free  acid  number  5-0,  and 
consequently  the  ester  number  195*0  —  5-0  =  190-0,  would 
theoretically  yield  190-0  x  -05466  *  10-39  per  cent,  of  glycerol. 

Proportion  of  Patty  Acids  formed  by  Saponifieation. — 
Just  as  the  average  molecular  weight  of  a  mixture  of  triglycerides 
or  other  compound  ethers  will  depend  partly  on  the  molecular 
weights  of  the  fatty  acids  formed  by  saponification,  and  partly  on 
those  of  the  alcoholic  or  glyceridic  constituents,  so  will  the 
percentage  of  fatty  acids  obtainable  vary  in  like  manner.  In  the 
case  of  a  mixture  of  glycerides,  where  some  of  the  fatty  acids  are 
of  low  molecular  weight,  obviously  a  smaller  percentage  of  fatty 
acids  will  be  formed  than  would  be  were  all  the  fatty  acids 
of  higher  molecular  weight.  Thus,  100  parts  of  butyrin, 
C3K5(O.C4HrO-)3,  would  theoretically  yield  87 '4  of  butyric  acid; 
whilst  100  parts  of  stearin,  C3H5(O.C18H35O)3,  would  similarly 
furnish  95 "7  parts  of  stearic  acid. 

In  certain  cases,  useful  information  is  obtainable  by  deter- 
mining the  total  percentage  of  fatty  acids  actually  produced, 
more  especially  when,  in  addition  to  the  total  percentage,  the 
amounts  respectively  soluble  and  insoluble  in  water  are  also 
deduced ;  the  information  being  in  some  cases  further  supple- 
mented by  determining  the  amount  and  nature  of  alcoholic  or 
glyceridic  complementary  products. 

The  total  percentage  of  fatty  acids  can  be  reckoned  from  the 
amount  of  alkali  requisite  for  saponification  (the  Kcettstorfer 
number  determined  as  indicated  on  p-.'161)  if  the  mean  equivalent 
of  the  fatty  acids  is  known ;  more  usually,  however,  the  latter  is 
the  principal  point  to  be  examined,  and  the  percentage  of  acids 
requires  to  be  directly  determined ;  from  which  value,  together 
with  the  quantity  of  alkali  used,  the  mean  equivalent  weight  of 
the  fatty  acids  is  deduced.  Thus,  if  100  parts  by  weight  of 
substance  yield  a  weight,  wv  of  fatty  acids  (i.e.,  if  wl  be  the 
percentage  of  fatty  acids  found),  and  w<,  parts  of  potash,  KOH, 
be  required  to  neutralise  these  acids,  the  mean  equivalent  weight 
of  the  acids  is  given  by  the  proportion — 

wa:  56-1  ::wi'.x  =  —  x  56'1. 
wa 

If  K  be  the  total  acid  number  (permillage  of  KOH,  or  ten  times 
the  percentage)  the  mean  equivalent  weight  of  the  fatty  acids 
will  obviously  be — 

56>1  =          x  56L 


164 


OILS,    FATS,    WAXES,    ETC. 


The  term  neutralisation  number  of  the  fatty  acids  (Versei- 
fungszahl  der  Fettsauren)  is  conveniently  employed  to  indicate 
the  quantity  of  potash  (KOH  =  56-1)  neutralised  by  1000  parts 
,of  the  free  acids.  This  value  and  the  mean  equivalent  weight  of 
the  free  acids  are  related  to  one  another  in  a  fashion  similar  to 
that  exhibited  by  the  total  acid  number,  and  the  saponification 
equivalent  of  the  original  fat  or  oil ;  if  N  be  the  neutralisation 
number  of  the  free  acids,  and  F  their  mean  equivalent  weight 
(value  of  x  as  above),  then 


whence 
and 


S"  :  56-1  ::  1000  :  F, 
_  56,100 

F 
^      56,100 

F  =  T- 


The  following  table  represents  the  average  neutralisation 
numbers  of  the  free  fatty  acids  obtained  from  various  kinds  of 
oils,  &c. — i.e.,  the  quantities  of  potash  (KOH  =  56-1)  neutralised 
'by  1,000  parts  of  mixed  free  fatty  acids  (Schadler) : — 


Name  of  Oil,  &c. 

Almond,  . 

Arachis, 

Cotton  seed, 

Castor, 

Cod  liver  (med  cinal), 

Charlock, 

Colza,  . 

Linseed, 

Lard,    . 

Nut  (walnut), 

Olive,  . 

Palm,  . 

Palm  kernel, 

Poppy, 

Suet  (ox),  , 

Sesame", 

Sunflower, 

Tallow  (sheep) 


Neutralisation  Number. 
204-205 
196-197 
204-205 
187-188 
202-204 
180-181 
181-182 
198-199 
215-217 
208-209 
199-200 
206-207 
265-266 
204-205 
205-206 
197-198 
201-202 
206-207 


In  the  case  of  a  triglyceride,  the  calculated  saponification 
equivalent  of  the  glyceride  always  exceeds  the  equivalent  weight 
of  fatty  acids  produced  from  it  by  saponification  by  12-67;  for  the 
general  reaction  of  saponification  being  equivalent  to 

CsH5(OrOs  +  3H20  -  C3H5(OH)3  +  3HOR 

where  R  is  a  fatty  acid  radicle,  it  results  that  the  molecular 
weight  (three  times  the  equivalent)  of  the  glyceride,  G,  plus 
3  x  18  =  54  parts  of  water,  is  identical  with  the  molecular 


NEUTRALISATION    NUMBER    OF    FATTY    ACIDS.  165 

weight  of  glycerol  =  92,  plus  three  times  the  equivalent  weight 
of  the  fatty  acid  formed  by  saponification,  3F ;  whence, 

G  =  3F  +  92  -  54, 

and  ^  -  F  +  12-67. 

o 

In  similar  fashion,  in  the  case  of  a  mixture  of  a  triglyceride  , 
and  the  fatty  acid  contained  therein  (e.g.,  tri stearin  and  stearic 
acid),  the  mean  saponification  equivalent  of  the  mixture  will 
exceed  the  equivalent  of  the  fatty  acid  by  a  fraction  of  the 
number  12 '6 7,  expressing  the  proportion  of  fatty  acid  contained 
as  glyceride  to  the  total  fatty  acid  present.  If  S  be  the  ester 

QJ 

number,  and  K  the  total  acid  number,  this  fraction  is  ^  ]  whence, 

,  -K. 

the  mean  saponification  equivalent  of  the  mixture,  M,  is  given 
by  the  equation 

'M  =  F  +  -  x  12-67. 
Jv 

Thus,  supposing  the  free  acid  number  to  be  5  per  cent.  (^V)  °f '• 
the  total  acid  number,  so  that  the  ester  number  is  95  per  cent. 
(^J)  thereof,  the  relationship  between  M  and  F  will  be 

M  =  F  +  II  x  12-67, 
=  F  +  12-04. , 

Similarly,  if  the  free  acid  number  be  10  per  cent.  (TTff)  of  the 
total  acid  number, 

M  =  F  + 11-40. 

Hence,  as  in  the  case  of  most  oils  and  fats,  the  amount  of  free 
acid  is  only  a  few  per  cents,  of  that  of  the  total  acids,  it  may  be 
taken  as  a  general  rule  that  the  mean  saponification  equivalent  of 
a  natural  oil  or  fat  exceeds  the  mean  equivalent  of  the  fatty  acids 
contained  therein  by  about  12  ;  and  by  a  proportionately  less 
amount  when  the  quantity  of  free  fatty  acid  present  increases 
beyond  a  few  per  cents. 

This  relationship  enables  comparisons  to  be  readily  instituted 
between  the  values  deduced  by  the  saponification  of  a  fat  or  oil, 
and  by  titrating  of  the  fatty  acids  separated  therefrom,  when 
expressed  as  equivalents  ;  whereas,  such  comparisons  are  much 
less  readily  made  by  means  of  the  potash  permillages  directly 
obtained,  viz.,  the  "total  acid  number"  of  the  glyceride,  and 
"  neutralisation  number"  of  the  free  acids  thence  derived  (p.  164). 

Since  the  saponification  equivalent  of  a  triglyceride  exceeds 
the  equivalent  weight  of  the  fatty  acid  contained  therein  by 


166  OILS,    FATS,    WAXES,    ETC. 

12  '6  7,  it  results  that  for  fatty  glycerides,  where  the  equivalent 
weight  of  the  fatty  acid  contained  lies  between  250  and  330,  the 
percentage  of  fatty  acid  yielded  by  the  glyceride  lies  between 
950  33Q 

°°'  between  95'2 


25CTT1W  '  330  +  12-67  ' 

and  96  -3  ;  so  that,  for  the  great  majority  of  natural  oils  and  fats 
containing  only  small  quantities  of  free  fatty  acids,  the  rest  being 
glycerides,  the  yield  of  fatty  acid  per  100  parts  of  fat  is  close  to 
95  -75  parts.  Fats  containing  a  considerable  amount  of  glycerides 
of  relatively  low  molecular  weight,  such  as  butter  fat,  cokernut 
butter,  and  palm  kernel  oil,  <fec.,  yield  proportionately  smaller 
percentages  of  fatty  acids  ;  on  the  other  hand,  if  much  free  fatty 
acid  is  present  in  the  fat  or  oil  examined,  the  percentage  yield  of 
fatty  acids  from  the  mixture  is  proportionately  increased. 


REFINER'S  TEST. 

This  test  consists  in  determining  that  fraction  of  the  fatty 
acids  formed  on  saponification  and  acidulation  which  remains 
undissolved  in  hot  water,  repeatedly  applied  until  no  more  acid 
is  dissolved.  With  most  oils  and  fats  this  quantity  differs  but 
little  from  the  total  percentage  (about  95-5  to  96  per  cent,  as  a 
rule,  supra] — i.e.,  only  minute  quantities  of  soluble  fatty  acids 
are  present ;  but  with  cow's  butter,  cokernut  butter,  and  some 
few  other  substances  the  difference  is  much  greater.  Thus  with 
butter  fat  the  total  percentage  is  usually  from  93  to  94,  whilst 
the  percentage  of  insoluble  acids  (the  Hehner  number)  is  only 
87  to  88.  With  the  fatty  glycerides  employed  in  the  manu- 
facture of  oleomargarine,  the  soluble  acids  are  present  in 
only  very  small  quantity,  so  that  the  insoluble  acids  amount  to 
95-96  per  cent. ;  hence,  any  considerable  admixture  of  oleo- 
margarine with  genuine  butter  is  detected  by  the  increment  in 
percentage  of  insoluble  acids  found. 

The  following  table  represents  the  proportion  of  genuine  butter 
fat  and  foreign  fats  (margarine)  present  in  a  sample  of  mixture 
yielding  a  higher  Hehner  number  than  genuine  butter  fat, 
assuming  this  to  give  the  value  87 '5,  and  margarine  to  give 
95-5. 

The  same  result  is  also  obtainable  by  means  of  the  formula 

x  =  (H  -  87-5)  x  12-5, 

where  H  is  the  observed  Hehner  number,  and  x  the  calculated 
percentage  of  margarine."55" 

*  When  cokernut  butter  (or  the  stearine  thence  isolated  by  chilling  and 
pressing)  is  substituted  for  oleomargarine  from  beef  suet,  &c.,  the  above 
table  does  not  hold  good. 


HEHNER'S  TEST. 


167 


Ilehner  Xumber  Found. 

Percentage  Present  of 

Genuine  Butter  Fat. 

Margarine. 

87  '5 

100 

0 

88 

93-75 

6-25 

88-5 

87'5 

12-5 

89 

81-25 

18-75 

89-5 

75 

25 

90 

68-75 

31-25 

90-5 

62-5 

37-5 

91 

56-25 

43-75 

91-5 

50 

50 

92 

43-75 

56-25 

92-5 

37-5 

62-5 

93 

31-25 

68-75 

93  '5 

25 

75 

94 

18-75 

81-25 

94-5 

12-5 

87-5 

95 

6-25 

93-75 

95-5 

0 

100 

Other  tests  depending  on  principles  somewhat  similar  to  those 
involved  in  Hehner's  test  have  been  proposed  by  other  chemists 
for  use  in  special  cases ;  thus  the  difference  in  solubility  of 
barium  salts  has  been  proposed  as  a  criterion  instead  of  the 
difference  in  solubility  of  free  acids  for  butter  analysis,  &c. 
A  modification  of  this  principle  is  utilised  as  a  means  of  deter- 
mining the  relative  proportions  of  stearic  and  oleic  acids  in 
mixtures  of  the  two  based  on  the  different  solubilities  of  their 
lead  salts  in  ether  (vide  p.  112). 


PRACTICAL  DETERMINATION  OF  THE  AMOUNT  OF 
FATTY  ACIDS  FORMED  ON  SAPONIFICATION 
(SOLUBLE  AND  INSOLUBLE  IN  WATER),  AND 
THEIR  AVERAGE  EQUIVALENT  WEIGHTS. 

The  neutralised  alcoholic  solution  left  after  determining  the 
saponifieation  equivalent  (or  the  product  obtained  by  saponifying 
&  larger  quantity  of  fat,  say  10  grammes,  with  alkali  without 
titratioii)  is  evaporated  to  drive  off  alcohol,  dissolved  in  hot 
water,  and  treated  with  an  excess  of  acid  (standardised  or  other- 
wise, according  to  circumstances — vide  infra) ;  a  few  minutes 
boiling  decomposes  all  soap  present,  so  that  a  clear  layer  of  fused 
fatty  acids  swims  up  to  the  top  on  standing.  A  weighed  filter 
(weighed  in  a  dish  after  drying  in  the  steam  bath)  is  prepared 
and  wetted  with  water  (otherwise  fatty  acids  may  pass  through), 
and  the  acidified  fluid  filtered  through,  the  oily  fatty  acids 


168  OILS,    FATS,    WAXES,    ETC. 

remaining  on  the  filter  being  washed  with  boiling  water  until 
no  more  acidity  is  found  in  the  filtrate.  The  filter  is  then  dried 
inside  the  weighed  dish,  and  thus  the  weight  of  insoluble  acids 
determined.  If  w  grammes  of  oil  give  n  grammes  of  insoluble 
acids,  the  "Hehner  number,"  H,  or  percentage  of  insoluble  acids, 
is  obviously 

H  =  n  -  x  100. 
w 

The  fatty  acids  thus  formed  are  dissolved  in  pure  alcohol  and 
titrated  with  standard  alcoholic  alkali  precisely  as  in  the  deter- 
mination of  the  "free  acid  number"  of  an  oil,  &c.  (p.  116).  The 
quantity  of  potash  (KOH  =  56*1)  neutralised  by  the  insoluble 
fatty  acids  obtained  from  1,000  parts  of  original  substance  is 
conveniently  referred  to  as  the  "  insoluble  acid  potash  per- 
millage,"  or  "insoluble  acid  number"  of  the  oil,  etc.,  examined. 

The  difference  between  the  quantity  of  potash  neutralised  in 
the  determination  of  the  saponification  equivalent  (total  acid 
number)  and  that  thus  found  as  the  insoluble  acid  number,  is 
obviously  the  potash  equivalent  to  the  acids  present  that  are 
soluble  in  water  ;  this  difference  is  conveniently  referred  to  as 
the  "soluble  acid  number"  of  the  oil,  &c.,  tested.  If  the  composi- 
tion of  these  soluble  acids  is  known  or  assumed  (e.g.,  regarding 
them  as  butyric  acid  in  the  case  of  butter  fat),  their  weight  is 
reckoned  from  the  alkali  neutralised  as  percentage  on  the  original 
fat  examined,  and  by  adding  this  value  to  that  deduced  as  above 
for  the  insoluble  acids,  the  percentage  of  total  acids  formed  is 
obtained. 

For  example,  suppose  2,500  grammes  of  butter  fat  to  be 
saponified  with  25  c.c.  of  seminormal  potash,  and  that  on 
titrating  the  excess  of  alkali  4  '9  c.c.  are  found  to  be  unneutralised 
by  the  acids  formed  on  saponification  ;  then  the  total  acids 
formed  are  equivalent  to  25  —  4'9  =  20*1  c.c.  of  serainormal 
alkali,  or  10  '05  c.c.  of  normal  alkali.  Hence  the  total  acid 
number  is 

56,100  =  225-5, 

and  the  saponification  equivalent  is 
2,500 


After  separation  of  the  insoluble  fatty  acids,  these  are  found  to 
weigh  2-187  grms.,  and  to  neutralise  16  '6  c.c.  of  seminormal 
alkali  =  8'3  c.c.  of  normal  alkali  \  hence  the  insoluble  acid 
number  is 

2,500  x5f'10)  =  U6-5; 
the  percentage  of  insoluble  fatty  acids  (Hekner  number)  is 


PRACTICAL    DETERMINATIONS.  169 


=87  '48; 


and  their  average  equivalent  weight  is 


i.e.,  1  c.c.  of  normal  alkali  neutralises  263'5  milligrammes  of  the 
mixed  acids.  Since  the  total  acids  neutralise  lO'Oo  c.c.  of  normal 
alkali,  and  the  insoluble  acids  8-3  c.c.,  the  difference  =  1'75  c.c. 
represents  the  soluble  acids.  This  corresponds  with  the  soluble 
acid  number 


If  it  be  supposed  that  the  soluble  acids  are  essentially  butyric 
acid  (equivalent  =  88),  1  c.c.  of  normal  alkali  will  neutralise 
88  milligrammes,  and  consequently  1'75  c.c.  will  neutralise  154 
milligrammes  =  6*16  per  cent,  of  the  2,500  grms.  of  butter  fat 
employed.  Hence  the  total  percentage  of  fatty  acids  formed  on 
sapomfication  is 

Insoluble  acids  (Hehner  number),        .         .         87  '48 
Soluble  acids  (reckoned  as  butyric  acid),     .  6'1G 

Total,         .         .         .         93-64 
The  mean  equivalent  weight  of  the  total  acids  is  deduced  thus  — 

Weight  of  insoluble  acids,  .         .         2,187  milligrammes. 

,,          soluble         ,,  .  154  ,, 

2,341 

Since  these  neutralise  20*1  c.c.  of  seminormal  alkali,  equivalent 
to  10*05  c.c.  of  normal  alkali,  the  mean  equivalent  weight  is 

O  QJ.1 

w'°*1      _   009-0 

10-05 

The  soluble  acids  may  also  be  directly  estimated  by  employing 
a  known  quantity  of  standard  acid  to  decompose  the  soap  left 
after  determination  of  the  saponifi  cation  equivalent,  and  deter- 
mining the  acidity  of  the  watery  nitrate,  using  phenolphthalein 
as  indicator.  Thus,  in  the  above  case,  suppose  that  25  c.c.  of 
seminormal  acid  were  used  to  decompose  the  soap,  and  that  8  '4 
c.c.  of  seminormal  alkali  were  neutralised  by  the  watery  filtrate  : 
since  the  alkali  present  in  the  neutral  soap  represents  20  -1  c.c., 
25  -  20-1  ==  4'9  c.c.  of  the  acid  used  would  remain  unneutralised 
in  the  filtrate;  whence,  8'4  —  4*9  =  3-5  c.c.  of  seminormal  acid, 
equal  to  1'75  c.c.  normal,  would  represent  the  soluble  acids  as 
before.  In  practice,  this  method  is  less  accurate  than  the  other, 
as  the  dilution  of  the  fluid  and  the  unavoidable  absorption 
of  carbonic  acid  from  the  air  (which  interferes  with  phenol- 


ci  CP    i  mo  /> 


170  OILS,    FATS,    WAXES,    ETC. 

phthalein  as  an  indicator)  generally  prevent  so  sharp  a  valuation 
being  obtained. 

With  the  exception  of  butter  fat  and  allied  animal  fats,  and 
cokernut  and  palmiiut  oils,  the  amount  of  soluble  acids  present 
in  ordinary  oils  and  fatty  matters  is  usually  so  small  as  to  be 
negligible,  so  that  the  total  acid  number  and  the  insoluble  acid 
number  are  sensibly  identical  —  i.e.,  the  amount  of  alkali 
neutralised  during  saponification  is  practically  identical  with 
that  neutralised  subsequently  by  the  liberated  fatty  acids, 
insoluble  in  water. 

Correction  for  Anhydro  derivatives,  e.g.,  Stearolac- 
tone. — Certain  distilled  oleines,  Turkey  red  oils,  &c.,  contain 
stearolactone,  the  "inner"  anhydride  of  7  oxystearic  acid  (p.  39); 
when  this  is  heated  with  alcoholic  potash,  it  forms  potassium 
oxystearate,  which  neutralises  an  equivalent  of  alkali  (C18H36O3 
=  300);  but  when  the  resulting  soap  is  decomposed  by  a  mineral 
acid,  stearolactone  is  reproduced.  If  the  mixed  fatty  acids,  &c., 
thus  formed  be  titrated  without  heating,  an  insoluble  acid 
number,  corresponding  with  only  the  free  fatty  acids,  will  be 
indicated,  the  stearolactone  not  being  converted  into  potassium 
oxystearate  instantaneously  in  the  cold;  so  that  an  apparent 
existence  of  soluble  fatty  acids  is  indicated  by  the  difference 
between  the  total  acid  number  obtained  at  first,  and  the  value 
obtained  during  the  titration  of  the  free  fatty  acids — i.e.,  their 
apparent  neutralisation  number.  The  difficiency,  however,  is 
made  up  if  the  neutralised  fatty  acids,  &c.,  be  heated  with  excess 
of  alcoholic  potash,  and  then  back-titrated,  so  as  to  determine  the 
alkali  neutralised  by  the  formation  of  oxystearate ;  from  the 
.amount  thus  neutralised  the  stearolactone  can  be  calculated, 
1  c.c.  of  normal  acid  representing  282  milligrammes.  Or  the 
stearolactone  may  be  dissolved  out  from  the  neutralised  fatty 
.acids  by  means  of  ether  or  benzoline,  and  directly  weighed  * 
(p.  119). 

Corrections  for  Free  Fatty  Acids  and  for  Unsaponinable 
Matters. — If  the  substance  examined  contain  free  fatty  acids  or 
unsaponifiable  matters  the  above  methods  require  certain 

rtH 

corrections ;   thus,   the  value    E  =  —    found   as   above   for   the 

n 

saponification  equivalent,  does  not  represent  the  true  equivalent 
of  the  glyceride  or  other  compound  ether  present  along  with 
other  matters,  but  only  the  mean  equivalent  of  all  the  substances 
present  (infinity  in  the  case  of  non-saponifiable  substances).  If, 
as  is  usually  the  case,  the  unsaponifiable  matters  present  are 
insoluble  in  water,  the  weight  of  substances  obtained  on  saponi- 
fying and  weighing  the  liberated  fatty  acids,  is  too  great  by  the 
amount  of  unsaponifiable  substances  present ;  and  also  by  the 

*  Benedikt,  Monatshefte fur  Chemie,  11,  p.  71. 


CORRECTIONS.  171 

weight  of  fatty  acids  originally  present  in  the  free  state  :  these 
are  determined  as  described  on  pp.  116,  119. 

Suppose  that  a  weight  of  substance,  W,  when  saponified  with 
alkali,  neutralises  n^  c.c.  of  normal  fluid ;  and,  as  the  result  of  a 
previous  titration  before  saponifying,  suppose  that  n.2  c.c.  represent 
the  normal  alkali  equivalent  to  the  free  fatty  acids  present  in  the 
same  weight,  W,  and  that  w1  milligrammes  is  the  weight  of 
these  fatty  acids.  Further,  let  the  weight  of  unsaponifiable 
matter  contained  in  W  of  substance  be  iv.2  milligrammes.  Then 
the  saponifiable  compound  ethers,  glycerides,  &c.,  present  weigh 
W  —  iv -^  —  w,-)  milligrammes ;  and  the  normal  alkali  neutralised 
by  them  on  saponification  is  n-^  -  n.2 ;  hence  the  corrected 
saponificatioii  equivalent  of  the  saponifiable  matters  free  from 
impurities  is 

w  "  w  ~  w 


and  the  potash  permillage  for  these  saponifiable  matters  free  from 
impurities  is 

K'  =       "i-"2        x  50,100. 


Sometimes  it  happens  that  during  saponification  products  are 
formed  that  are  insoluble  in  water  and  consequently  swim  up  to 
the  top  when  the  resulting  soaps  are  decomposed  by  a  mineral 
acid  so  as  to  separate  the  fatty  acids  formed  by  saponification  ; 
e.g.,  in  the  case  of  cetacean  oils,  waxes,  &c.,  where  alcohols  of 
high  molecular  weight,  and  not  glycerol,  are  set  free;  in  such 
cases,  in  order  to  obtain  a  correct  valuation  of  the  fatty  acids, 
the  quantity  of  such  alcohols,  &c.,  mixed  with  them  must  be 
determined.  *  This  is  usually  conveniently  effected  by  evaporat- 
ing to  dryness  the  alcoholic  solution  obtained  when  the  weighed 
impure  acids  have  been  titrated  (p.  164),  and  dissolving  away  the 
alcohols,  &c.,  with  ether  or  benzoliiie,  so.  as  to  separate  them  from 
the  soap  ;  the  filtered  solution  thus  obtained  is  then  evaporated, 
and  the  residue  weighed  and  subtracted  from  the  weight  of  crude 
fatty  acids. 

The  equivalent  weight  of  the  fatty  acids  then  will  be 


where  iv  is  the  weight  in  milligrammes  of  crude  fatty  acids, 
tv  that  of  alcohols,  etc.,  admixed  therewith,  and  n  the  number  of 
c.c.  of  normal  alkali  neutralised. 

*  Owing  to  saponification  changes  occurring  on  keeping  or  during 
refining,  it  sometimes  happens  that  considerable  quantities  of  ,cet37lic, 
dodecylic,  &c.,  alcohols  are  contained  as  such  in  sperm  oil,  spermaceti, 
beeswax,  and  similar  substances,  in  addition  to  those  existing  as  compound 
ethers  ;  as  much  as  40  to  50  per  cent,  has  been  found  in  extreme  cases 
{Allen  and  Thomson). 


172  OILS,    FATS,    WAXES,;   ETC. 

Mean  Equivalent  of  Fatty  Acids  Contained  in  Soap.— 

In  the  examination  of  soap  it  is  often  required  to  determine  the 
mean  equivalent  of  the  fatty  acids  present  therein  as  potash  or 
soda  soap;  methods  of  calculation  analogous  to  the  above  are 
then  used.  In  such  cases  the  analytical  methods  used  (Chap, 
xxi.)  usually  give  the  following  data  : — 

Percentage  of  total  alkali  present  (reckoned  say  as  Xa20),      =     a 
,,  alkali   not   combined  with  fatty  acids  (so 

called  "free  alkali "),      .         .         .         .      —     b 
,,  free  fatty  acids  formed  on  decomposition  of 

the  soap  by  mineral  acids  (together  with 
unsaponified  fat  and  neutral  bodies,  &c.),      =     c 
,,  unsaponified  fat  and  neutral  bodies,  &c.,       .      =     d 

Then  100  parts  of  material  contain  a  —  b  per  cent,  of  alkali 
(reckoned  as  Na2O)  combined  as  soap  with  fatty  acids,  which 
soap  again  yields,  on  decomposition  by  a  stronger  acid,  c  -  d  per 
cent,  of  fatty  acids  free  from  unsaponified  fat  and  neutral  bodies. 
The  mean  equivalent  E  of  these  fatty  acids  is  then  given  by  the 
proportion  (31  being  the  equivalent  of  sodium  oxide,  Na.,0) 

a  -  6     :     31     :  :     c  -  d     :     E, 

whence  E  =   •  x  31. 

a  -  o 

The  fatty  acids  yielded  by  cokernut  oil  have  an  average  equi- 
valent weight  of  not  far  from  200,  whilst  those  from  tallow, 
palm  oil,  and  olive  oil  have  much  higher  values,  near  275,  still 
higher  equivalent  weights  being  possessed  by  the  mixtures  of 
acids  yielded  by  castor  oil  (near  300)  and  oil  of  ben  and  rape 
oil  (near  330°) ;  cerotic  and  melissic  acids  from  beeswax  have 
equivalent  weights  of  410  and  452  respectively.  Hence  in 
many  cases  the  numerical  value  of  the  equivalent  weight  of  the 
fatty  acids  affords  a  useful  indication  as  to  the  nature  of  the  oils, 
&c.,  used  in  manufacturing  the  soap  examined. 

Calculation  of  Composition  of  a  Mixture  of  Two  Fatty 
Acids  from  their  Mean  Neutralisation  Number. — In  certain 
cases  where  a  substance  is  examined  known  to  be  a  mixture  of 
two  different  fatty  acids,  the  relative  amounts  of  the  two  consti- 
tuents can  be  at  least  approximately  calculated  from  their  mean 
neutralisation  number.  Thus  in  the  case  of  a  mixture  of  palmitic 
acid  (molecular  weight  =  256)  and  stearic  acid  (284),  let  the 
neutralisation  number  of  the  mixture  be  n  ;  the  mean  molecular 

weight  of  the  mixture  will  accordingly  be  —       —  (p.  164).    Hence 

the  following  table  gives  the  relative  proportions  of  the  two 
acids  : — 


REICHERT'S  TEST. 


173 


Percentage  of 

Mean  Molecular  Weight. 

Palmitic  Acid. 

Stearic  Acid. 

256 

100 

0 

258-8 

90 

10 

2S1  -6 

80 

20 

264-4 

70 

30 

267-2 

60 

40 

270-0 

50 

50 

272-8 

40 

60 

275-6 

30 

70 

278-4 

20 

80 

281-2 

10 

90 

284-0                                       0 

100 

The  following  formula  gives  the  same  result :— Let  S  be  per- 
centage of  stearic  acid,  and  M  the  mean  molecular  weight  ;  then 

S  =  (M  -  256)  x  — 

x& 

=  (M  -  256)  x  3-5716. 

In  similar  fashion  the  relative  proportions  of  any  other  two  fatty 
acids  in  a  mixture  thereof  can  be  calculated. 


REICHERT'S   TEST. 

Various  natural  oils  and  fats  yield  on  saponification  the  alkali 
salts  of  mixtures  of  acids,  some  of  which  are  readily  volatile  with 
the  steam  of  water  at  ordinary  pressure,  and  others  practically 
non- volatile.  Reichert  *  has  based  on  this  a  useful  method  for 
the  examination  of  butter  as  regards  adulteration  with  other 
kinds  of  fatty  matter  (oleomargarine,  &c.),  these  adulterants 
furnishing  much  smaller  proportions  of  volatile  acids.  In  prac- 
tice, it  is  not  convenient  to  continue  the  distillation  until  all  the 
volatile  acid  present  has  passed  over,  so  that  a  particular  method 
of  manipulation  is  employed,  in  order  that  an  approximately 
constant  fraction  of  the  volatile  acids  may  be  distilled  off.  For 
this  purpose  2-5  grammes  of  the  fat  to  be  examined  are  heated 
with  25  c.c.  of  approximately  seminormal  alcoholic  potash  in  a 
flask  with  reflux  condenser,  until  saponification  is  complete ;  the 
alcohol  is  evaporated  off  (by  transferring  to  an  evaporating  dish), 
and  the  residue  dissolved  in  water,  slightly  acidulated  with 
dilute  sulphuric  acid,  and  made  up  to  70  c.c.,  of  which  50  are 
distilled  offf  The  distillate  is  filtered  if  solid  acids  insoluble  in 

*  Zeits.  Anal.  Chem.,  18,  p.  68. 

t  To  avoid  bumping,  pumice  stone  with  platinum  wire  coiled  round  should 
be  placed  in  the  distilling  vessel. 


174 


OILS,    FATS,    WAXES,    ETC. 


cold  water  have  passed  over,  and  titrated  with  decinormal  alkali, 
using  phenolphthalein  as  indicator.  Working  in  this  way  about 
-|  of  the  total  volatile  acids,  soluble  in  water,  of  genuine  butter 
are  obtained  in  the  distillate. 

The  following  table  is  given  by  A.  H.  Allen,*  representing 
the  collected  results  obtained  by  himself  and  other  analysts 
employing  this  method  of  manipulating  :— 


C.c.  of  Decinormal 

Substance  of  which  2'5  grammes  are  used. 

Alkali  neutralised  by      Percentage  of  KOII 
Distillate  (filtered                neutralised. 

when  necessary). 

MILK  FATS  — 

Cow's  butter,    .... 

12  -5  to  15  "2            2  -SO  to  3  -41 

Ewe's  butter,    .... 

13-7 

3-07 

Goat's  butter,    .... 

13-G 

3-05 

Porpoise's  butter, 

11-3 

2-51 

ANIMAL  &  VEGETABLE  OILS  &  FATS— 

Cokerimt  oil,t  .... 

3-5  to  37 

078  to  0-83 

Palmnut  oil,      .... 

2-4 

0-54 

Palm  oil,  

0-8 

0-18 

Cacao  butter,    .... 

1-6                           0-36 

Butterine  and  oleomargarine,    . 

0-2  to  1-6 

0-04  to  0-36 

Whale  oil,         .... 

37  to  12-5 

0-83  to  2  -SO 

Porpoise  oil,       .... 

11  to  12 

2-47  to  2-69 

Sperm  oil,          .... 

1-3 

0-29 

Bottlenose  oil,  ....                    1*4 

0'31 

Menhaden  oil,  .... 

1-2                           0-27 

Cod  liver  oil,     .... 

1-1  to  21             0-24  to  0-47 

Sesame  oil,        .... 

2-2 

0-48 

Cotton  seed  oil, 

0-3 

0-07 

Castor  oil,          .... 

1-4 

0-31 

Meissl  i  slightly  modifies  Eeichert's  test  by  using  5  grammes 
of  fat  instead  of  2 -5;  the  evaporated  alcoholic  soap  is  dissolved  in 
100  c.c.  of  water,  and  acidified  with  40  c.c.  of  10  per  cent, 
sulphuric  acid  solution.  110  c.c.  are  distilled  off,  of  which  100  is 
filtered  through  a  dry  filter  and  titrated,  the  decinormal  alkali 
consumed  being  increased  by  one  tenth,  to  allow  for  the  10  c.c. 
not  used.  The  results  are  usually  somewhere  about  double  those 
obtained  by  Reichert's  method  of  manipulation — i.e.,  are  much 
the  same  per  given  weight  of  butter,  taking  into  account  the 
doubled  weight  of  fatty  matter  used. 

The  following  table  is  given  by  Schadler,  representing  the 
number  of  c.c.  of  decinormal  alkali  neutralised  by  the  volatile 

*  Commercial  Organic  Analysis,  vol.  ii.,  p.  46. 

t  By  adding  more  water  and  continuing  the  distillation,  a  large  amount 
of  solid  fatty  acid,  mostly  insoluble  in  water  (chiefly  lauric  acid),  can  be- 
distilled  over  in  the  case  of  cokernut  oil. 

J  Dingier s  Poly.  Journ.,  233,  p.  229. 


REICHERT'S  TEST. 


175 


acids  distilled  off  when  the  Reichert-Meissl  test   is    employed 
(5  grammes  of  material  used)  :  — 

Xame  of  Oil,  &c. 
Arachis,       . 
Almond, 
Cotton  seed, 
Cokernut,    . 
Cod  liver,    . 
Castor, 
Colza,  crude, 

,,       refined, 
Lard, 
Linseed, 
Nut  (walnut), 
Olive, 
Palm, 

.,     kernel, 
Poppy, 
Seal  oil, 
Sesame', 
Sunflower,  . 
Tallow  (ox), 

„       (sheep), 

Several  other  modifications  of  Reichert's  mode  of  manipulating 
have  been  proposed  by  different  chemists  with  the  object  of 
obtaining  greater  accuracy  ;  thus  Wollny  *  employs  special 
precautions  to  avoid  the  presence  of  carbon  dioxide  in  the 
distillate  and  eliminate  its  disturbing  effect,  and  prescribes  that 
the  distillation  (using  5  grammes  of  butter  fat)  should  always 
last  the  same  time,  30  minutes.  Similarly,  Leffmann  and  Beam 
use  a  solution  of  caustic  soda  in  glycerol  instead  of  alcohol,  to 
diminish  possible  formation  of  volatile  acids  by  the  action  of  the 
alkali  on  the  alcohol.  Methylic  alcohol  is  used  by  others  for 
the  same  purpose.  Admitting  that  pure  butter  fat  gives  a 
Reichert-Wollny  number  =  27,  and  that  the  corresponding 
number  for  average  margarine  is  2,  then  a  sample  of  butter  fat 
mixed  with  margarine  and  giving  the  number  R  will  contain 
x  per  cent,  of  margarine,  where 


C.c. 

of  Decinormal  Alkali. 

0-4 

0'55 

0-95 

7-3 

0-4 

4-0 

0-90 

0-58 

MO 

0-95 

0-92 

1-5 

0-5 

3-4 

0-6 

2-6 

1-2 

0-5 

1-0 

1-2 

x  =  100  x 


—  =  4  (27  - 


The  term  "Reich  ert  number"  (Reichert  'sche  ZaJtl)  is  frequently 
given  to  the  figure  expressing  the  number  of  c.c.  of  decinormal 
alkali  neutralised  by  the  distillate  obtained  when  operating  in 
the  way  prescribed  by  Reichert,  using  2*5  grammes  of  substance; 
and  similarly  the  terms  "Reichert-Meissl  number"  and  "Reichert- 
Wollny  number  "(IteicJwrt-MewsrscfoZahl  and  JReichert-  Wollny'  sche 
ZaliT)  to  the  corresponding  figures  obtained  when  Meissl's  or 
"Wollny's  modification  of  Reichert's  process  is  used  (employing 

*  The  Analyst,  1887,  p.  203,  et  sea.;  from  the  Milch  Zeitung,  1887, 
Nos.  32-35. 


176  OIL?,    FATS,    WAXES,    ETC. 

o  grammes  of  substance).  The  two  latter  numbers  are  each 
approximately  double  the  first  on  account  of  the  larger  weight  of 
material.  To  avoid  confusion  between  these  different  values,  it 
is  convenient  to  translate  them  into  terms  of  caustic  potash 
(KOH  =  56-1)  neutralised  by  the  volatile  acid  obtained  from 
1,000  parts  of  substance,  to  which  value  the  term  "volatile  acid 
number"  (or  volatile  acid  potash  permillage)  may  be  conveniently 
applied  ;  this  translation  is  effected  by  means  of  the  formulae — 

Volatile  acid  number  =  Reichert  number    .         .      x  2 '244 
,,  ,,  =  Reichert-Meissl  number       x  1'122 

,,  ,,  =  Reicherb-Wollny  number     x  l'J22 

The  volatile  acids  thus  indicated  are  usually  considerably  below 
the  total  amount  actually  present;  according  to  Allen,  the  defi- 
ciency is  somewhere  about  one-fifth  in  the  case  of  butter  fat,  and 
presumably  in  about  the  same  proportion  in  other  cases.  When 
a  nearer  approximation  is  requisite  to  the  total  volatile  acid 
present,  water  must  be  added  to  the  residue  in  the  retort  and 
distillation  recommenced,  and  so  on  as  long  as  acid  vapours  pass 
over ;  or  more  conveniently,  steam  may  be  blown  through  the 
liquid  from  a  separate  boiling  vessel. 


BROMINE  AND  IODINE  ABSORPTION. 

Organic    compounds    containing   a   group    of    the    character 

—  CR  =  CS  -  tend  to   combine   with   two   atoms    of  a    given 
halogen  such  as  bromine  or  iodine,  forming  a  group  of  formula 

-  CKBr  -  CSBr  -  ,  or  -  CRI  -  CSI  -  .   Accordingly,  organic  acids 
thus  constituted  are  capable  of  uniting  directly  with  halogens  to 
an  extent  dependent  on  the  number  of  times  that  such   "  doubly 
linked "   carbon  groups  occur ;  thus    oleic  and  ricinoleic  acids, 
which    contain  one  such   doubly  linked  pair  of  carbon  atoms, 
unite  with  Br.,. 

Oleic  Acid.  Dibromostearic  Acid. 

C17H33.CO.OH          +        Br2         =         C,7H33Br2 .  CO  .OH 

Ricinoleic  Acid.  Dibromoxystearic  Acid. 

P        TT  fOH  TC  p        TT        -R          /OH 

Ci7H32 1  CQ    OH  C17H32Br2  j  CQ    OH 

Similarly,  linolic  acid  combines  with  Br4,  as  it  contains  two  *  such 
doubly-linked  pairs  of  carbon  atoms. 

Linolic  Acid.  Tetrabromostearic  Acid. 

C]7H31.CO.OH      +      Br4      =      C17H31Br4.  CO.  OH 
Whilst  linolenic  acid,  containing  3  such  pairs,!  unites  with  Br0 — 

Linolenic  Acid.  Hexabromostearic  Acid. 

C17H29.CO.OH      +      Br6      =      C17H29Br6.  CO .  OH 

*  Or  possibly  a  trebly-linked  pair  of  carbon  atoms,  forming  the  group 

—  CJ— C  -,  which,  by  uniting  with  Br4,   produces  a  group  of  formula 

-  CBr^-  CBr,-. 

t  Or  possibly  one  trebly-linked  pair,  and  one  doubly-linked  pair. 


BROMINE    ABSORPTION.  177 

In  certain  cases,  the  bromine  addition  products  thus  formed 
are  crystallisable,  and  thus  afford  the  means  of  separating  organic 
acids  from  one  another  (pp.  27, 35, 36);  in  any  case,  by  determining 
the  quantity  of  halogen  fixed  by  a  given  acid  or  mixture  of  acids, 
useful  information  is  often  obtained  as  to  the  nature  of  the  fatty 
acids  present ;  for  instance,  if  a  mixture  of  stearic  and  oleic  acids 
took  up,  say,  45  per  cent,  of  its  weight  of  iodine,  since  stearic 
acid  takes  up  no  iodine,  and  oleic  acid  90  per  cent,  of  its  weight, 
it  would  result  that  the  mixture  contained  the  two  acids  in 
approximately  equal  quantities.  Methods  for  the  determination 
of  the  amount  of  oleic  acid  in  mixtures  of  this  kind  are  of 
considerable  practical  utility;  in  particular,  the  author  has 
found  the  method  useful  in  determining  the  proportion  of  oleic 
acid  contained  in  the  "  stearine  "  used  for  candle  making. 

Precisely  the  same  remarks  also  apply  to  the  glycerides  of  the 
fatty  acids,  with  the  sole  difference  that  their  combination  with 
halogens  generally  takes  place  more  slowly  than  is  the  case  with 
the  fatty  acids  contained,  or  with  the  parent  hydrocarbons  of 
these  fatty  acids. 

As  far  back  as  1857,  attempts  to  utilise  the  reaction  with 
bromine  for  the  practical  discrimination  of  fats  were  made  by 
Cailletet,  and  subsequently  by  A.  H.  Allen,  Mills,  and  others; 
but  although  in  certain  cases  useful  results  are  thus  obtainable, 
in  practice  it  is  found  that  the  use  of  iodine  is  preferable,  more 
especially  when  applied  in  the  modified  form  proposed  by  Hiibl 
(vide  infra),  where  mercuric  chloride  and  iodine  are  dissolved  in 
alcohol,  and  the  compound  solution  allowed  to  act  on  the  fat. 

in  this  case,  the  product  formed  is  not  simply  an  iodine 
addition  product ;  the  mercuric  chloride  appears  to  be  ntore  or 
less  transformed  into  mercuric  iodide,  with  formation  of  chloride 
of  iodine,  so  that  the  addition  product  contains  both  chlorine  and 
iodine;  thus  oleic  acid,  C18H34O2,  treated  with  this  reagent 
becomes  mostly  converted  into  chloriodostearic  acid,  C18H34C1IO2, 
and  similarly  in  other  cases.  The  chlorine  thus  added  on  is  in 
practice  never  reckoned  as  such,  but  as  its  equivalent  in  iodine  ; 
so  that  282  parts  of  oleic  acid,  when  treated  with  Hiibl' s  reagent, 
are  regarded  as  combining  with  2  x  127  =  256  parts  of  iodine, 
although  usually  the  compound  produced  is  formed  by  taking  up 
127  parts  of  iodine  +  35-5  parts  of  chlorine. 

Bromine  Process. — The  bromine  absorption  process,  as  im- 
proved by  Mills  and  Snodgrass,*  and  Mills  and  Akitt,f  consists 
in  dissolving  bromine  in  carbon  disulphide,  or  preferably  carbon 
tetrachloride,  to  a  solution  containing  0'6  to  O7  per  cent,  of 
bromine,  and  adding  this  to  a  solution  of  a  weighed  quantity 
of  oil  in  the  same  solvent,  until  no  more  combination  takes  place. 
In  the  earlier  experiments  with  carbon  disulphide  a  slight  excess 
of  bromine  was  added,  and  the  colour,  after  standing  15  minutes, 

*  Journ.  Soc.  Chem.  Industry,  1883,  p.  435.          t  Ibid.,  1884,  p.  366. 

12 


178 


OILS,    FATS,    WAXES,    ETC. 


Substance. 

Percentage 
of  Bromine 
absorbed. 

Specific 
Gravity  at 

ll°-12e. 

Melting 
Point. 

Remarks. 

Almond  oil, 

26-27 

•9168 

... 

Expressed  from  bitter 

almonds. 

. 

53-74 

•9154 

... 

Expressed  from   sweet 

almonds  ;  yellower. 

Beeswax, 

0-54 

63-9 

English,  a  few  months 

old  ;  very  yellow. 

>»                • 

0 

632 

Scotch,  8  years  old  ;  pale. 

0 

... 

62-9 

,,      2       ,,       yellow. 

,  ,                                    •                   • 

0 

... 

63-3 

"       *•       '  >           » 

Ben  oil,    . 

52-95 

•9198 

... 

Much  solid  fat. 

. 

50-89 

•9161 

... 

No  solid  fat. 

Camauba  wax, 

33-50 

... 

84-1 

Cod  liver  oil,    . 

83-12 

•9269 

Scotch,  7  years  old  ;  ran- 

cid ;  clear  portion  used; 

1  hour's  absorption. 

»» 

84-03 

•9292 

... 

Norwegian,   refined,  2 

years  old. 

82-94 

•9257 

... 

Japanese,  2  years  old. 

. 

81-61 

•9277 

Scotch,  2  years  old. 

< 

86-69 

•9281 

... 

Crude,  from  liver  refuse  ; 

a  few  months  old. 

. 

83-01 

•9318 

... 

Norwegian,  1  year  old. 

. 

82-07 

•9278 

Scotch                   ,, 

Croton  oil, 

46-66 

•D441 

... 

20  hours'  absorption. 

Eucalyptus  oil, 

94-09 

•8691 

... 

... 

Horse  fat, 

35-67 

... 

... 

Pasty  ;  well  mixed. 

Japan  wax, 

2-33 

... 

50-5 

,,  (another  sample), 

1-53 

... 

50-8 

Java  nut  oil,    . 

30-24 

... 

... 

... 

Ling  liver  oil, 

82-44 

•9295 

... 

2  years  old  ;    1  hour's 

absorption. 

Maize  germ  oil, 

74-42 

•9262 

4  years  old. 

Mustard  seed  oil, 

46-15 

•9152 

East  Indian. 

Myrtle  wax,     . 

6-34 

... 

44-3 

... 

Neat's  foot  oil, 

38-33 

•9147 

... 

Thick. 

Niger  seed  oil, 

35-11 

•9244 

... 

Olive  oil, 

59-34 

•9266 

... 

Thick  brown  ;     '  '  best 

sulphocarbon." 

?9                                 *                 * 

60-61 

•9382 

... 

Thinner  greener  ;  '  '  low 

quality  sulphocarbon." 

Palm  oil, 

35-44 

... 

... 

Crude  old  Calabar. 

5  )                                    •                  * 

34-96 

... 

... 

,,      Lagos. 

Peach  kernel  oil, 

25'40 

•9175 

... 

... 

Poppy  oil, 
Besin.  (common), 
Seal  oil,    . 

56-54 
112-70 
57-34 

•9244 
•9241 

... 

Turbid;  filtered. 
Light  colour. 
Pale;  1  hour's  absorption. 

J  5                   •                 •                 • 

59-92 

•9216 

Dark. 

Sesame  oil, 

47-35 

•9250 

... 

... 

Shark  liver  oil, 

84-36 

•9293 

... 

A   few   months   old  ; 

1  hour's  absorption. 

Sunflower  oil,  . 

54-32 

•9391 

Colourless  ;    about    16 

years  old. 

Whale  oil, 

30-92 

•9199 

... 

Norwegian  white  whale; 

very  thick. 

>» 

48-69 

•8780 

... 

Bottlenose  whale. 

HUBL'S  IODINE  TEST.  179 

compared  with  that  of  a  known  amount  of  bromine  dissolved  in 
carbon  disulphide,  so  as  to  obtain  a  colorimetric  valuation  of  the 
excess ;  or  the  excess  of  bromine  was  estimated  by  adding 
potassium  iodide  and  titrating  with  thiosulphate.  In  the  later 
experiments  with  carbon  tetrachloride,  about  Ol  gramme  of 
oil  was  dissolved  in  50  c.c.  of  tetrachloride,  an  excess  of  bromine 
solution  added,  and  after  15  minutes  the  excess  back-titrated, 
either  by  the  coloration  method,*  by  iodide  and  thiosulphate, 
or  by  a  standard  solution  of  j3  naphthol  in  carbon  tetrachloride. 

The  table  on  p.  178  gives  the  results  of  a  number  of  deter- 
minations thus  made. 

Iodine  Process — Hiibl's  Test. — The  iodine  absorption  pro- 
cess of  Baron  Hubl  is  thus  worked,  f  An  alcoholic  solution  of 
mercuric  chloride  and  iodine  in  pure  95  per  cent,  alcohol  is  pre- 
pared by  dissolving  50  grins,  iodine  in  one  litre  of  spirit,  and 
60  grms.  corrosive  sublimate  in  another  litre,  filtering  the  latter 
if  necessary,  and  mixing  the  two  solutions ;  preferably  they  are 
kept  apart  and  only  mixed  a  day  or  two  before  use ;  J  the  com- 
pound solution  rapidly  loses  strength  (as  regards  free  iodine)  if 
fusel  oils  are  present  in  the  alcohol,  methylated  spirit  being  wholly 
inadmissible;  in  any  case  the  liquid  should  be  allowed  to  stand  at 
least  a  day  before  use,  so  that  any  small  quantity  of  iodine- 
consuming  impurities  may  be  eliminated  as  far  as  possible ;  the 
actual  iodine  strength  must  be  determined  from  time  to  time  to 
allow  for  depreciation.  From  -2  to  *3  grm.  of  drying  oils,  '3  to  '4 
of  non-drying  oils,  or  -8  to  1  -0  grm.  of  solid  fat,  is  dissolved  in 
10  c.c.  of  pure  chloroform  (i.e.,  containing  no  iodine-destroying 
impurity),  and  to  the  solution  30  or  40  c.c.  of  iodine  solution 
added,  more  being  added  if  on  standing  awhile  the  brown  colour 
lightens  materially  ;  enough  solution  must  be  added  in  all  to 
give  a  large  excess  of  free  iodine  when  the  action  is  complete 
after  several  hours  standing.  The  excess  of  iodine  is  titrated  by 
adding  some  aqueous  potassium  iodide  solution  (10-15  c.c.  of 
10  per  cent,  solution,  along  with  150  c.c.  of  water),  and  then 
standard  sodium  thiosulphate  (about  24  grms.  to  litre,  standard- 
ised by  means  of  pure  sublimed  iodine,  or  by  pure  potassium 
dichromate)  until  the  blue  colour  with  starch  paste  is  just 
decolorised,  the  starch  being  only  added  when  nearly  all  the  free 

*  When  the  oil  is  yellow,  as  with  certain  fish  oils,  the  redness  due  to 
excess  of  bromine  is  best  examined  by  viewing  through  a  solution  of 
potassium  chromate. 

t  Dingler's  PolytecJt.  Journal,  1884,  pp.  253,  281  ;  in  abstract,  Journ* 
Soc.  Chem.  Intl.,  1884,  p.  641. 

£  According  to  Say  tzetf,  mercuric  bromide  is  preferable  to  corrosive  sub- 
limate, the  solution  being  more  stable.  Some  chemists  only  mix  the  two 
solutions  at  the  moment  they  are  wanted  ;  but  according  to  the  author's 
experience,  this  considerably  increases  the  chances  of  error.  If  mercuric 
chloride  be  not  added  at  all  (e.g.,  if  a  solution  of  iodine  in  carbon  tetra- 
chloride be  used),  the  quantity  of  iodine  absorbed  is  in  some  cases  largely 
diminished  as  compared  with  that  taken  up  with  Hiibl's  fluid. 


180  OILS,    FATS,    WAXES,    ETC. 

iodine  is  destroyed.  As  the  excess  of  iodine  is  dissolved  partly 
in  the  aqueous  liquor  and  partly  in  the  chloroform,  the  whole 
must  be  well  agitated.  Unless  a  considerable  excess  of  free 
iodine  is  present,  and  the  whole  allowed  to  stand  for  several 
hours,  defective  results  are  apt  to  be  obtained  with  glycerides,  as 
the  assimilation  of  iodine  with  these  bodies  is  not  always  rapid ; 
free  fatty  acids  combine  with  iodine  more  quickly.  A  good  rule 
is  to  use  an  excess  of  iodine  approximately  equal  to  the  amount 
absorbed, *  and  to  allow  the  whole  to  stand  until  the  next  day 
before  titration  of  the  uncombined  iodine  ;  one  or  more  blank 
experiments  being  simultaneously  arranged  to  allow  for  possible 
depreciation  in  strength  of  the  iodine  solution  during  the  period  ; 
this  lengthened  time  is  more  especially  requisite  in  the  case  of 
oils  absorbing  large  amounts  of  iodine.  Thus  the  following 
figures  illustrate  this  point  (Thomson  and  Ballantyne)  : — 


Iodine  Number  found. 

Time  of  Absorption. 

——  -,  

—  . 

Seal  Oil. 

Linseed  Oil. 

2  hours. 

136-6 

175-5 

4      „ 

140-8 

1797 

6      „ 

145-1 

184-1 

8      „                             145-8 

1877 

18      „                             145-8 

187-7 

Similar  figures  have  been  published  by  various  other  observers  in 
the  case  of  glycerides  absorbing  large  proportions  of  iodine,  whereas, 
with  free  fatty  acids  and  glycerides  absorbing  but  little  iodine,  the 
reaction  is  ordinarily-found  to  be  practically  complete  in  2  hours. 

When  the  iodine  absorption  of  free  iatty  acids  is  to  be 
determined,"  it  is  unnecessary  to  dissolve  in  chloroform ;  the 
alcoholic  mercury-iodine  solution  may  be  added  directly  to  the 
weighed  fatty  acids,  previously  thinned  a  little  by  warming 
with  a  small  quantity  of  pure  alcohol.  The  following  table 
represents  the  amounts  of  iodine  theoretically  taken  up  by  100 
parts  of  the  several  acids  and  their  respective  triglycerides  : — 


«     •       •  Iodine  Absorption. 

Acid. 

Giyceride. 

Hypogieid  acid,     '      -    :      . 
Oleic  acid, 

CieH3002        •      100*00 
Ci8H3402               9007 

95-25 

86-20 

Erucic  acid,      .    ;  •      -     .   ,' 

.    C22H4202               75*15 

72-43 

Ricinoleic  acid, 

Cj8H3403               85*24 

81-76 

Linolic  acid,     .            -        -          C]8H3202 

173-57    : 

Linolenic  acid,                              C]gH3002    •  j        274'10 

262-15 

*  In  the  case  of  oils  absorbing  large  quantities  of  iodine,  a  still  greater 
excess  is  preferable,  about  twice  the  quantity  absorbed.  In  all  cases  the 
quantity  of  iodine  used  for  the  blank  experiment  should  be  approximately 
equal  to  the  excess  employed. 


IODINE    TEST. 


181 


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182 


OILS,    FATS,    WAXES,    ETC. 


In  actual  practice,  Hiibl  found  that  pure  oleic  acid  took  up 
8 9 '8-90 '5  per  cent,  of  iodine,  and  obtained  the  values  quoted  011 
p.  181  on  examining  a  variety  of  fats  and  oils  by  different  pro- 
cesses simultaneously,  the  substances  being  divided  into  7  classes, 
according  to  the  magnitude  of  the  iodine  absorption. 

Schadler  gives  the  following  values  as  those  most  generally 
found  pertaining  to  various  oils  and  fats,  &c.  : — 


Name  of  Oil  or  Fat. 

Iodine  Number  of 

Oil,  &c.                            Fatty  Acids. 

82-83 
100-102 
94-96 
28-32 
66  68 
34 
93-94 
98-97 
100-101 
9-9-5 
106-107 
127 
128-130 
135-140 
143-144 
105 
4-2 
177-178 
162 
59-60 
119-5 
142-143 
82-83 
82 
51-5 
13-5-14 
134-135 
121 
98-100 
38-40 
125-130 
103-105 
129 
88 
108 
63 
43-44 
81-5-82 
36 

87-90 
96-97 

56-57 

97-99 
8-5-9-0 
112-115 

122-124 

155 
167 

125 

87-88 

12 

97-99 
26-30 

110-111 
133-134 

86-87 

Apricot  kernel, 
Arachis, 
Butter, 
Bone,     .                            . 
Cacao  butter, 
Castor,  .                            . 
Charlock,       . 
Colza,    .         .                   . 
Cokernut, 
Cotton  seed, 
Curcas, 

c-dlMS±r1>  :    : 

Hedge  radish, 
Japanese  wax, 
Linseed, 

Lallemantia  (Gundschit), 

Nut  (walnut), 
Olive  (salad), 
Olive  kernel, 
Palm,    ....." 

Palm  kernel, 
Poppy,           .... 
Pumpkin  seed, 
Rape  seed,     .... 
Suet  (ox  tallow,  beef  tallow), 
Seal,      . 

Sesam6,          .... 
Sunflower,     .... 
Sperm  oil,      .... 
Spermaceti,  .... 
Tacamahac,  .         .   " 
Tallow  (sheep),      . 
Ungnadia,      .... 
Wool  grease, 

The  following  tables  represent  the  collected  results  published 


IODINE    TEST. 


183 


by  numerous  observers,* '  during  the  last  few  years,  as  the 
amounts  of  iodine  taken  up  by  100  parts  of  different  oils  and 
fats  :  — 

VEGETABLE  OILS. 


Name. 

Minimum. 

Maximum. 

Average. 

Fresh  linseed  oil,  . 

170 

181 

175 

Commercial  oil,     . 

148 

181 

170 

Lallemantia  oil,     .         .         . 

162 

Hemp  seed  oil,      .         . 

142 

158 

150 

Nut  oil,         .... 

143 

152 

146 

Poppy  seed  oil, 

134 

142 

138 

Sunflower  seed  oil, 

122 

133 

128 

Curcas  oil,     .... 

... 

127 

Pumpkin  seed  oil, 

... 

121 

Maize  oil,      .... 

... 

120 

Cotton  seed  oil, 

102 

Ill 

108 

Sesame  oil,    .... 

103 

112 

108 

Hedge  radish  oil,  . 

... 

105 

Rape  seed  oil, 

99 

105 

101 

Apricot  kernel  oil, 

99 

102 

100 

Almond  oil, 

96 

102 

98 

Arachis  oil,  .... 

87-3 

103 

96 

Mustard  oil, 

... 

... 

96 

Castor  oil,     . 

83 

85 

84-5 

Olive  oil,        . 

81 

84-5 

82-8 

Olive  kernel  oil,    . 

... 

... 

81-8 

ANIMAL  OILS. 


Name. 

Minimum. 

Maximum. 

Average. 

Cod  liver  oil, 

126 

153 

140 

Seal  oil,         .... 

127 

128 

127 

Japanese  cod  liver  oil, 

... 

... 

120 

Bottlenose  oil, 

... 

... 

99-5 

Porpoise  oil, 

... 

76'8 

Neat's  foot  oil, 

70-3 

Bone  oil,        .... 

66 

70 

68 

Porpoise  oil  oleine, 

30-9 

49-6 

40-2 

Bottlenose  oleine,  . 

... 

32-8 

*  Hiibl,  Moore,  Dieterich,  Wilson,  Erban,  Herz,  Spiiller,  Horn,  Richter, 
Kremel,  Beringer,  and  Benedikt ;  collated  by  Bsnedikt. — Analyse  der  Fette 
und  Wachsarten,  2nd  edition,  pp.  298  and  317. 


184 


OILS,  FATS,  WAXES,  ETC. 
SOLID  FATS. 


Name. 

Minimum. 

Maximum. 

Average. 

Cotton  seed  stearine, 

89-6 

Goose  grease, 

... 

71-5 

Hog's  lard,    .... 

56 

63 

59 

Macassar  oil, 

... 

53 

Bone  grease, 

46-3                  55-5 

52 

Palm  butter, 

50-3                 53-9 

51 

Oleomargarine.      . 

47'5                 55-3                 50 

Laurel  butter, 

49 

Ox  tallow,     .... 

40 

44                     42 

Sheep's  tallow, 

32-7                  46-2                 42 

Wool  grease, 

36 

Cacao  butter, 

34                  37-7                 36 

Nutmeg  butter,     . 

31 

Butter  fat,    . 

19-5 

38-0 

30 

Palm  kernel  butter, 

10-3 

17-5 

14 

Coker  butter, 

7-9 

9-4 

9 

Japanese  wax, 

... 

4-2 

Slightly  higher  values  still  for  some  of  the  drying  oils  have 
been  recently  deduced  by  Holde  in  the  course  of  an  investigation 
on  the  sources  of  error  in  the  Hiibl  test,*  the  cause  being 
assigned  to  more  complete  saturation  with  iodine  through  use 
of  a  larger  excess  of  solution.  Thus — 

Linseed  oil, 179  to  180 

Hempseed  oil, 175 

Poppy  seed  oil, 139  to  143 

Sesame"  oil, 106  to  109 

Cotton  seed  oil, 110  to  115 

Common  rape  oil, 100  to  108 

Refined  rape  oil, 100  to  107 

The  following  values  have  also  been  recorded  for  the  mixed 
fatty  acids  from  various  commercial  oils  : — 


Morawski  and  Demski. 

Williams. 

Linseed  oil  acids,  .         .                  . 
Hempseed  oil  acids, 
Cotton  seed  oil  acids,     . 
Sesame  oil  acids,   .         .                   . 
Rape  seed  oil  acids, 
Arachis  oil  acids,  .                            .         . 
Castor  oil  acids,     .                            . 
Olive  oil  acids,       ..... 

155  -2  to  155  -9 
122-2  to  125  -2 
110-9  to  111-2 
108-9  to  111-4 
96-3  to    99-02 
95-5  to    96-9 
86  -6  to    88-3 
86-1 

178-5 
115-7 
105*6 

93-9 

90-2 

Owing  to  the  tendency  towards  absorption  of  oxygen  exhibited 
by  drying  oils  and  the  fatty  acids  obtained  from  them,  there  is 

*  Journ.    Soc.   Chem.   Ind.,    1891,   p.    954;    from  Mitth.   Kcnigl.   tech. 
Vcrsuchs,  Berlin,  1891,  9,  p.  81. 


IODINE    TEST.  185 

always  a  liability  to  obtain  somewhat  different  results  with  free 
fatty  acids  as  compared  with  the  original  oils  from  which  they 
were  obtained,  owing  to  partial  oxidation  during  isolation  and 
drying.  As  a  rule,  absorption  of  oxygen  seems  to  diminish  the 
iodine  absorption  as  might,  a  priori,  be  expected. 

Neglecting  this  alteration,  the  amounts  of  iodine  absorbed  by 
an  oil,  &c.,  and  by  the  fatty  acids  thence  obtainable,  necessarily 
stand  to  one  another  in  the  inverse  ratio  of  their  respective 
mean  equivalent  weights  ;  for  if  E  be  the  saponification  equiva- 
lent of  an  oil,  and  F  the  mean  equivalent  weight  of  the  fatty 
acids  thence  obtainable,  quantities  of  oil  and  free  acid  in  the 
respective  proportion  of  E  to  F  will  combine  with  the  same 
quantity  of  iodine ;  so  that  the  iodine  taken  up  by  100  parts  of 

oil  will  be  ^  times  that  taken  up  by  100  parts  of  fatty  acids  ; 
.hi 

i.e.,  if  I  be  the  iodine  number  of  the  oil  and  I'  that  of  the  fatty 
;icids — 


and 


<•=!'• 


If  the  oil,  &c.,  consist  wholly  of  triglycerides,  E  =  F  +  12  -67 
(p.  165);  whence 

F  +  12  67 

~~ 


Hence  for  fatty  acids  of  molecular  weight  between  250  and  330, 
the  iodine  number  of  the  fatty  acids  is  between  5'1  and  3-8  per 
cent,  greater  than  that  of  the  original  oil  ;  so  that  for  the  great 
majority  of  natural  oils  and  fats,  the  iodine  number  of  the  free 
fatty  acids  exceeds  that  of  the  oil  by  an  amount  sensibly  close  to 
4-5  per  cent,  of  the  latter  value. 

Obviously,  in  some  of  the  cases  above  tabulated,  a  notable 
difference  must  have  subsisted  between  the  samples  used  for  the 
determination  of  the  iodine  number  of  a  given  oil,  and  of  that  of 
the  fatty  acids  derived  from  the  same  kind  of  oil,  since  the  latter 
values  are,  in  some  instances,  less  than  the  former  ones  instead 
of  exceeding  them  by  about  4  '5  per  cent,  of  their  value. 

The  theoretical  amount  of  iodine  corresponding  with  100  parts 
of  pure  olein  is  86-2  parts.  From  the  numbers  above  tabulated, 
it  is  obvious  that  many  of  the  fluid  vegetable  oils,  usually 
regarded  as  non-drying  (arachis,  almond,  apricot  kernel,  &c.), 
contain  some  small  amount  of  glycerides  of  the  linolic  or  drying 
class,  since  their  iodine  absorptions  exceed  86  -2  ;  a  fortiori,  with 
oils  of  the  intermediate  class  exhibiting  a  slight  amount  of 


186 


OILS,    FATS,    WAXES,    ETC. 


drying  quality  (cotton  seed,  sesame,  sunflower,  &c),  a  larger 
iodine  absorption  is  observed,  corresponding  with  a  still  more 
marked  proportion  of  drying  oil  constituents. 


ACETYLATION   TEST  —  BENEDIKT   AND 
ULZER'S  TEST. 

When  organic  substances  containing  alcoholiform  hydroxyl  are 
heated  in  contact  with  acetic  anhydride,  an  action  takes  place 
which  may  be  regarded  as  the  converse  of  saponincation  or 
hydrolysis  ;  the  hydroxylated  body,  X  .  OH,  acts  upon  the 
anhydride  in  accordance  with  the  equation  — 

Alcohol.  Acetic  Anhydride.         Compound  Acetic  Ether.  Acetic  Acid. 

X-OH      +       8$$}°      =      X.O.C.H.O      +     C2H3o!0 

giving  rise  to  a  compound  ether.  Polyhydroxylated  bodies 
behave  in  the  same  way,  one  acetyl  group  being  taken  up  for 
each  alcoholiform  hydroxyl  group  present  ;  thus  glycerol  treated 
with  acetic  anhydride  becomes  transformed  into  triacetin  in 
accordance  with  the  equation  — 

Glycerol.  Acetic  Anhydride.  Triacetin.  Acetic  Acid. 

CH2  .  OH  CH,  .  O  .  C,H30 

CH  .  OH        +       3(CoH30)oO      =      CH.  0  .  aH30       +       3C.,H4O, 

CH2  .  OH  CH2  .  0  .  CoH30 

On  this  reaction  is  based  a  method  for  the  analytical  examination 
of  commercial  glycerol  (Chap,  xxn.)  Benedikt  and  Ulzer  have 
also  attempted  to  utilise  this  reaction  to  distinguish  hydroxylated 
organic  acids  (like  oxystearic  and  ricinoleic  acids)  from  non- 
hydroxylated  acids,  such  as  stearic  and  palmitic  acids.  Their 
method  is  based  on  the  assumption  that  acetic  anhydride  exerts 
no  action  on  the  hydroxyl  of  the  CO  .  OH  group  of  an  organic 
acid,  but  does  act,  in  accordance  with  the  above  equation, 
on  any  alcoholiform  hydroxyl  contained  therein  ;  so  that  if,  for 
example,  stearic  acid  be  treated  with  acetic  anhydride,  and  the 
product  heated  wrih  water  so  as  to  decompose  excess  of  acetic 
anhydride,  simply  unchanged  stearic  acid  results;*  whereas,  if 
oxystearic  acid  be  similarly  treated,  acetyl  oxystearic  acid  is 
produced,  thus  — 

Oxystearic  Acid.  Acetic  Anhydride.  Acetyl  Oxystearic  Acid.  Acetic  Acid. 


OH  C,H30  )  n  \0.  CoHsO 

CO  .  OH  C2H30  \  U  ^ITUM  j  co  .  OH 

The  acetylated  acids  thus  formed  are  stated  to  be  moderately 
stable,  not  being  appreciably  hydrolysed  by  the  action  of  the  hot 

*  This  assumption  is  entirely  at  variance  with  the  results  obtained  by 
Lewkowitsch  ;  vide  infra. 


ACETYLATION    TEST  —  BENEDIKT   AND    ULZER's    TEST.  187 

water  requisite  to  decompose  the  excess  of  acetic  anhydride  pre- 
sent. Accordingly,  if  after  thus  removing  excess  of  acetic  anhy- 
dride, the  resulting  acetyl  acid  be  titrated  with  standard  alkali, 
one  equivalent  of  alkali  will  be  directly  neutralised  ;  whilst  if  it 
be  heated  with  excess  of  alcoholic  alkali  so  as  to  saponify  it, 
reproducing  oxystearic  acid  and  acetic  acid,  thus  — 

Acetyl  Oxystearic  Acid.  Water.  Oxystearic  Acid.  Acetic  Acid. 

+     H,0  C17H34  +     CoH40 


two  equivalents  will  be  neutralised  in  all,  the  second  by  the 
acetic  acid  formed.  In  the  case  of  a  mixture  of  acids  containing 
hydroxylated  and  non-hydroxylated  constituents,  the  proportion 
of  the  latter  can  be  estimated  by  determining  the  extra  amount 
of  potash  neutralised  on  saponification,  as  compared  with  that 
neutralised  directly.  The  term  "  acetyl  number  "  (acetylzahl], 
is  used  to  indicate  the  weight  of  potash  (KOH  =  56*1)  neutral- 
ised by  the  acetic  acid  formed  from  1,000  parts  of  mixed 
acetylated  product.* 

The  acetylation  process  is  carried  out  thus  :  —  The  free  fatty 
acids  formed  by  saponifying  a  given  sample  of  oil  and  decom- 
posing the  soap  by  a  mineral  acid,  are  boiled  for  two  hours  with 
an  equal  volume  of  acetic  anhydride  in  a  flask  with  inverted 
condenser  attached  ;  the  mass  is  then  boiled  for  half  an  hour 
with  about  20  parts  of  water  ;  the  acetic  acid  solution  formed  is 
siphoned  off,  and  the  treatment  with  boiling  water  repeated  three 
times,  so  that  finally  the  water  is  free  from  acidity  after  boiling 
for  half  an  hour.  The  acetylated  product  is  then  filtered  through 
a  dry  filter  paper  to  remove  water,  and  a  weighed  quantity 
dissolved  in  pure  alcohol.  Standard  alcoholic  potash  is  added  to 
neutrality,  and  the  amount  neutralised  noted;  more  than  as  much 
again  is  then  added,  and  the  whole  heated  to  boiling,  whereby 
the  acetyl  derivative  is  saponified  ;  the  unneutralised  alkali  is 
then  back-titrated.  Thus  in  the  case  of  the  fatty  acids  from  a 
sample  of  castor  oil  the  following  figures  were  obtained  :f  —  3-379 
grammes  of  acetylated  product  neutralised  17  '2  c.c.  of  seminormal 
potash,  whence  the  "  acetyl  acid  number  "  is  142-8.  After 

*  Benedikt  and  Ulzer  term  the  potash  directly  neutralised  by  1,000  parts 
of  mixed  acetylated  product,  the  "acetyl  acid  number  "  (acetylsaurezahl), 
and  the  total  neutralised  on  saponification  (sum  of  acetylzahl  and  acetyl- 
fiiiurezahl)  "the  acetyl  saponification  number"  (acetylverseifunyszahl). 
Thus  the  theoretical  values  tor  acetyl  oxyoleic  (ricinoleic)  acid  are  — 

Acetyl  number,         .         .  .     165'0 

Acetyl  acid  number,          .         .         .     IGo'O 

Acetyl  saponification  number,   .     330  '0 
t  Benedikt,  Analyse  der  Fette  und  Wacltsarten,  2nd  edition,  1892,  p.  114. 


188 


OILS,    FATS,    WAXES,    ETC. 


addition  of  32 -8  c.c.  more  potash  and  boiling,  14*3  c.c.  were  found 
to  be  unneutralised,  whence  18 '5  c.c.  represent  the  acetic  acid 
formed  on  saponification,  giving  the  "  acetyl  number"  153-6,  and 
the  "acetyl  saponification  number"  142-8  +  153-6  =  269-4. 
Since  the  acetyl  number  exceeded  the  acetyl  acid  number,  it  would 
hence  result  that  some  amount  of  a  dihydroxylated  acid  was  pre- 
sent, especially  as  the  mixed  acids  of  castor  oil  contain  a  small 
quantity  of  stearic  (non-hydroxylated)  acid  to  begin  with  (vide 
infra}. 

Operating  in  this  way,  Benedikt  and  Ulzer  found  the  following 
values  for  various  oils  : —  * 


Oil  Used. 

"Neutralisation 
Number"  of 
Fatty  Acids 
before 
Acetylation. 

Acetyl  Acid 
Number. 

Acetyl 
Number. 

Acetyl 
Saponification 
Number. 

Arachis, 

198-8 

193-3 

3-4 

1967 

Cotton  seed,    . 

199-8 

195-7 

16-6 

212-3 

Croton,  . 

201-0 

1957 

8-5 

204-2 

Hemp  seed,     . 

199-4 

196-8 

7'5 

204-3 

Linseed, 

201-3 

196-6 

8-5 

205-1 

Almond, 

201-6 

196-5 

5-8 

2023 

Poppy  seed,    . 

200-6 

194-1 

13-1 

207-2 

Nut,        . 

204-8 

198-0 

7-6 

205-0 

Olive,      . 

197-1 

197-3 

4-7 

202-0 

Peach  kernel, 

202-5 

196-0 

6-4 

202-4 

Castor,    . 

177-4 

142-8 

153-4 

296-2 

Rape, 

182-5 

178-5 

6-3 

184-8 

Sesame,  . 

200-4 

192-0 

11-5 

203-5 

"Soluble  castor  oil  " 

184-5 

62-2 

246-7 

J.  A.  Wilson  f  found  the  following  average  values  for  castor, 
olive,  and  cotton  seed  oils  : — 


Acetyl  Acid 
Number. 

Acetyl  Number. 

Acetyl  Saponification 
Number. 

Castor  oil, 
Olive  oil,     . 
Cotton  seed  oil, 

136-7 
170-0 
189-5 

155-0 
360 
21-0 

291-7 
2060 
210-5 

Obviously  these  figures  do  not  agree  very  sharply  with  the 
preceding  ones.  If  the  results  of  the  acetyl  test  could  be  re- 
garded as  perfectly  trustworthy,  these  values  would  indicate  the 
existence  of  more  or  less  considerable  amounts  of  hydroxy  acids  in 
all  the  samples  examined,  amounting,  in  the  case  of  the  cotton  seed 
and  sesame  oils  examined  by  Benedikt  and  Ulzer,  to  6-8  per  cent, 
of  the  total  acids  present,  and  to  much  larger  amounts  in  the 

*  Monat'hefte  f.  Chemie,  1S87,  S,  p.  41. 
•\Journ.  Soc.  Chem.  Intl.,  1892,  p.  495.- 


ACETYLATION    TEST.  189 

case  of  the  olive  and  cotton  seed  oils  examined  by  Wilson.  The 
figures,  however,  do  not  exhibit  such  concordance  as  to  be 
unexceptionable ;  the  effect  of  acetylating  the  hydroxylated  con- 
stituents of  a  mixture  of  acids  containing  only  a  small  proportion 
of  hydroxylated  acids  would  be  to  cause  the  neutralisation  number 
of  the  acetylated  fatty  acids  (the  acetyl  acid  number)  to  be  only 
slightly  less  than  their  neutralisation  number  before  acetylation, 
whereas  the  observed  differences  are  materially  larger.  Thus 
the  neutralisation  numbers  of  oleic,  oxyoleic,  and  acetyl  oxyoleic 
acids  are  respectively  198-9,  188-25,  and  165-0;  whence  a 
mixture  of  90  parts  oleic  acid  and  10  parts  oxyoleic  acid  would 
have  the  neutralisation  number  197*9  ;  and  after  acetylation 
would  furnish  a  mixture  of  oleic  and  acetyl  oxyoleic  acids  having 
the  neutralisation  number  (acetyl  acid  number)  195'5,  or  only 
2*4  less  than  the  original  mixture.  Similarly  a  mixture  of 
9o  parts  oleic  acid  and  5  parts  oxyoleic  acid  would  have  the 
neutralisation  number  198-4  before  acetylation,  and  197*2  after, 
giving  the  difference  1-2.  The  actual  differences  deduced  from 
the  above  figures  obtained  by  Benedikt  and  Ulzer  with  oils  other 
than  castor  oil,  vary  between  —  0*2  (olive  oil)  and  +8-4  (sesame 
oil),  but  in  most  cases  amount  to  from  5  to  6;  strongly  suggesting 
that  some  cause  is  at  work  abnormally  diminishing  the  "  acetyl 
acid  number "  by  some  units,  and  in  consequence  giving  an  ap- 
parent "  acetyl  number  "  of  some  units  in  magnitude,  the  result 
of  this  cause,  and  not  of  the  existence  of  hydroxy  acids  in  the  fatty 
asids  examined.  The  same  conclusion  also  results  from  the  figures 
obtained  with  castor  oil  acids,  as  the  supposition  that  a  consider- 
able percentage  of  dihydroxylated  acids  is  present  is  manifestly 
untenable. 

Lewkowitsch  has  made  some  observations  that  throw  light  on 
the  probable  cause  of  these  discrepancies.*  His  results  indicate 
that  by  the  action  of  acetic  anhydride  in  excess  the  higher  acids 
of  the  acetic  family  (such  as  lauric,  palmitic,  and  stearic  acids, 
&c.)  become  more  or  less  completely  converted  into  the  corre- 
sponding anhydrides.f  When  the  products  freed  from  the 
excess  of  acetic  anhydride  by  the  action  of  water  are  neutralised 
by  alkali,  a  diminution  in  the  apparent  amount  of  free  acid  is 
noticed  proportionate  to  the  amount  of  fatty  anhydrides  present 
not  decomposed  by  the  water  treatment ;  and  when  the  neutral- 
ised substance  is  heated  with  excess  of  alcoholic  alkali,  and 
subsequently  back-titrated,  a  quantity  of  alkali  is  neutralised 
proportionate  to  the  fatty  acid  formed  by  the  hydration  of  the 

*  Proceeding*  of  the  Chemical  Society,  1890,  pp.  72  and  91. 

t  Anschiitz  found  [Aimalen  d.  Chem.  Pharm.  (1884)  226,  p.  6]  that  when 
acetic  anhydride  and  benzoic  acid  were  heated  together  in  a  sealed  tube  at 
220°  benzoic  anhydride  was  produced  ;  whilst  the  dibasic  acids,  succinic, 
camphoric,  orthophthalic,  and  diphenic  acids  were  largely  transformed  into 
their  respective  anhydrides  by  heating  with  acetic  anhydride  at  120° 
to  150°. 


190 


OILS,    FATS,    WAXES,    ETC. 


fatty  acid  present;  so  that  an  apparent  "acetyl  number"  is 
obtained  even  when  no  alcoholiforin  hydroxyl  whatever  is  present 
in  the  body  examined.  Thus  he  obtained  the  following  figures 
with  samples  of  capric,  lauric,  palmitic,  oleic,  stearic,  and  cerotic 
acids  in  a  state  of  only  approximate  purity  so  far  as  chemical 
identity  is  concerned,  but  any  rate  free  from  any  notable  amount 
of  hydroxy  acids  :— 


NeutraHsutio 

n  Number. 

Acetyl 

Fatty  Acid  Used. 

Theoretical 

Acetyl  Acid 
Number. 

Acetyl 
Number. 

Saponification 

for  pure 

Found. 

1 

fatty  acid. 

Capric, 

326-2 

318-05 

176-40 

174-00 

350-40 

Lauric, 

280-5 

273-02 

161-50 

132-49 

293-99 

Palmitic, 

219-1 

213-4 

143-53 

82-60 

222-13 

Oleic,  . 

198-0 

183-0 

116-50 

125-55 

242-05 

Stearic, 

197-5 

203-0 

138-89 

82-29 

221-18 

Cerotic, 

13t>-8 

1284 

73-87 

68-23 

142-10 

From  these  figures  it  obviously  results  that  but  little  reliance 
is  to  be  placed  on  the  result  of  the  acetylation  test  for  alcoholi- 
form  hydroxyl  in  fatty  acids  when  based  simply  on  the  titra- 
tioii  process  above  described.  Better  results,  however,  can 
be  obtained  by  modifying  the  test  in  the  way  proposed  by 
Lewkowitsch  •*  the  acetylated  product  is  saponified  with  alcoholic- 
potash,  the  alcohol  boiled  off,  and  the  residue  distilled  with 
dilute  sulphuric  acid,  much  as  in  Reichert's  test  (p.  173).  Any 
acetic  acid  formed  by  hydrolysis  of  acetyl  derivatives  is  thus, 
distilled  over,  and  may  be  titrated  by  means  of  standard  alkali 
and  phenolphthalein.  In  this  way  dioxystearic  acid  (from  oleic 
acid  by  alkaline  permanganate)  was  found  to  form  the  anhydride 

O    TT      /Q    p  TT  r\\      rir\  \ 

of  diacetyloxystearic  acid,  p17TT84  /Q  '  p2TT8O»2  TO  I  ^'  on  ^rea*~ 
ment  with  acetic  anhydride ;  from  this  acetic  acid  was  obtained 
on  saponificatioii  and  distillation  in  quantity  but  little  below 
the  theoretical  amount.  A  revision  of  the  fatty  acids  obtainable 
from  oils  and  fats,  &c.  (as  regards  the  amount  of  hydroxylated 
constituents  present),  based  on  the  acetyl  test  thus  applied 
would  be  desirable,  but  as  yet  does  not  appear  to  have  been 
made. 

On  the  other  hand,  the  acetylation  test  gives  good  results  with 
bodies  not  of  an  acid  character,  containing  alcoholiform  hydroxyl, 
more  especially  in  the  case  of  the  higher  homologues  of  ethylic 
alcohol :  thus  in  the  examination  of  waxes  and  bodies  generally 
that  give  rise  to  higher  alcohols,  the  amount  of  hydroxylated 
substances  present  may  be  measured  by  conversion  into  com- 

*  Journ.  Soc.  Chem.  Ind,  1890,  p.  842. 


METHYL    IODIDE    TEST — ZEISEI/S    TEST.  191 

pound  ethers  by  means  of  acetic  anhydride,  and  determining  the 
permillage  of  potash  neutralised  on  saponifying  the  product. 
Thus  pure  cetylic  alcohol,  C16H33 .  OH,  furnishes  an  acetyl  deri- 
vative, cetyt  acetate,  C16H33 .  O  .  C2H3O,  of  molecular  weight  284— 
i.e.,  284  milligrammes  of  cetyl  acetate  will  furnish  60  milligrammes, 
of  acetic  acid  on  saponification,  neutralising  Ic.c.  of  normal  potash 
solution  containing  56'1  milligrammes  of  potash  (KOH);  whence 

the   "acetyl  number"  of  cetyl  acetate   is  ^    .   x   1000  =  197'5. 

If  a  given  sample  of  cetyl  alcohol  (known  to  be  admixed  with 
foreign  matter  not  capable  of  forming  acetyl  derivatives)  furnish 
an  acetyl  derivative  of  which  the  acetyl  number  is  found  to  be  98, 
obviously  about  one  half  of  the  substance  is  cetylic  alcohol.  A 
more  exact  value  is  obtained  by  determining  the  quantity  of 
foreign  matter  present,  subtracting  that  from  the  weight  of 
acetylated  product,  and  reckoning  the  acetyl  number  on  the 
difference  as  1000,  in  a  way  similar  to  that  adopted  in  the  parallel 
case  of  the  determination  of  the  Koettstorfer  number  of  a  saponi- 
fiable  body  after  correction  for  unsaponifiable  matters  present 
(p.  171). 

In  the  case  of  impure  glycerol  the  acetylation  test  is  employed 
in  a  similar  way  ;  92  parts  of  pure  glycerol  would  furnish  3  x  60 
=  180  parts  of  acetic  acid  on  saponification  of  the  triacetiii 
formed  therefrom,  capable  of  neutralising  3  x  56 '1  =--  168 -3  parts 
of  potash.  If  a  given  sample  of  impure  glycerol  were  found  to 
neutralise  n  parts  of  potash  per  92  of  substance,  the  percentage 

M 

of  glycerol  present  would  be  TgcTTo  x  100.  Or  otherwise,  92  milli- 
grammes of  pure  glycerol  would  furnish  acid  neutralising  3  c.c. 
of  normal  alkali  solution ;  hence  if  a  weight  w  milligrammes  of 
impure  glycerol  furnish  acid  neutralising  x  c.c.  the  percentage 

I  x  92 
of  glycerol  would  be x  100  •»— .  x  3066-7. 

IV  W 

Iii  the  examination  of  the  unsaponifiable  matters  left  011  treat- 
ing oils  and  fats,  &c.,  with  alkalies  (p.  121),  the  substance  may 
conveniently  be  converted  into  acetyl  derivative  by  treatment 
with  acetic  anhydride,  boiled  with  water  to  decompose  excess  of 
anhydride,  crystallised  from  alcohol,  and  examined  as  to  the 
acetyl  number  obtained  on  saponification  of  the  product ;  choles- 
terol acetate  (006H43 .  O  .  C.,H3O)  and  its  isomerides  thus  give  the 
number  135 -5. 


METHYL  IODIDE  TEST— ZEISEL'S  TEST. 

Compound  ethers   of  methylic   alcohol  and   its   next  higher 
homologues  do  not  appear  to  have  been  hitherto  recognised  as 


192  OILS,    FATS,    WAXES,    ETC. 

important  constituents  of  natural  fixed  oils  and  fats,  although 
the  corresponding  compounds  of  the  higher  homologues  of 
methylic  alcohol,  such  as  cetylic  alcohol,  are  well  marked  con- 
stituents of  certain  cetacean  oils,  waxes,  &c.  Many  essential 
oils,  however,  contain  constituents  of  analogous  character — 
e.g.,  oil  of  wintergreen,  largely  consisting  of  metliyl  salicylate, 

(  OTT 
C6H4  -j  £Q    Q    £jT  .     Another  class  of  essential  oils  containing 

the  methoxyl  group  (O  .  OH3)  also  exists,  where  the  hydrogen 
displaced  by  methyl  is  alcoholiform  in  character,  and  not  con- 
tained in  the  organic  acid  group  CO  .  OH  ;  thus,  anetkol  or  anise 
oil  camphor  is  the  methylic  ether  of  a  phenoloid  derived  from 
allyl-benzene,  C3H5.  C(.H4.  0.  CH.,.  When  substances  containing 
a  methoxyl  group  are  heated  in  contact  with  hydriodic  acid,  a 
reaction  is  brought  about  whereby  the  methyl  group  is  elimi- 
nated in  the  form  of  methyl  iodide,  thus — 

Methoxyl  Compound.  Hydriodic  Acid.       Methyl  Iodide.       Hydroxyl  Compound. 

X .  0  .  CH3          +        HI  CH3I        +        X .  OH 

A  test  for  the  presence  of  methoxyl  in  certain  bodies  (e.g., 
codeine)  based  on  this  action  was  employed  by  the  author  as  far 
back  as  1871,*  the  methyl  iodide  vapours  evolved  being  passed 
through  a  red  hot  combustion  tube  containing  lead  chromate, 
so  as  to  burn  the  methyl  iodide,  the  resulting  carbon  dioxide 
being  absorbed  by  potash  bulbs  in  the  usual  way.  Zeisel  t  has 
modified  the  process  by  determining  the  iodine  contained  in  the 
methyl  iodide  produced  instead  of  the  carbon ;  for  this  purpose 
the  vapours  of  methyl  iodide  evolved  are  carried  off  by  a  stream 
of  carbon  dioxide  and  received  in  bulb  tubes  containing  alcoholic 
silver  nitrate,  intercepting  vessels,  &c.,  being  employed  to  pre- 
vent vapours  of  hydriodic  acid  or  iodine  from  passing  over  also. 
On  standing,  diluting  with  water,  and  adding  nitric  acid,  silver 
iodide  is  precipitated,  the  weight  of  which  is  a  measure  of  the 
amount  of  methyl  iodide  formed,  and  consequently  of  the  pro- 
portion of  methoxyl-containing  substances  present. 

Fig.  33  represents  the  arrangement  employed  by  Benedikt 
and  Griissner ;  a  few  decigrammes  of  substance  are  heated  with 
10  c.c.  of  hydriodic  acid  solution  of  sp.  gr.  1'70  in  the  flask  A, 
warmed  by  means  of  a  glycerol  bath  ;  a  current  of  carbon  dioxide 
is  led  through  the  flask,  the  issuing  vapours  passing  through  a 
3-bulb  condenser,  bulb  I.  being  empty  to  condense  steam,  &c. ; 
bulb  II.  contains  water  to  absorb  hydriodic  acid ;  and  III., 
red  phosphorus  and  water  to  retain  any  traces  of  free  iodine 

*  Proceedings  of  the  Royal  Society,  xx.,  p.  8  (1871). 

t  Journ.  Soc.  Chem.  Ind.,  1886,  p.  335;  from  Monatsh.  f.  Chemie,  vi., 
p.  989.  See  also  Journ.  Soc.  Chem.  Jnd.,  1889,  pp.  735  and  923  (Benedikt 
and  Griissner). 


ZEISEL  S    TEST. 


193 


evolved  by  decomposition  of  hydriodic  acid  by  heat.  After 
passing  through  the  bulbs  the  carbon  dioxide,  mixed  with  methyl 
iodide  vapour,  is  led  into  the  flask  B  containing  5  c.c.  of  a  40  per 
cent,  solution  of  silver  nitrate  and  50  c.c.  of  95  per  cent,  alcohol; 
the  safety  flask  D  contains  1  c.c.  of  the  same  silver  solution  with 
10  c.c.  of  alcohol,  but  is  usually  unnecessary,  all  methyl  iodide 
being  retained  in  the  first  flask  B. 

Substances  containing  ethoxyl  (O  .  C2H5)  and  homologues  are 
similarly  affected ;  as  the  molecular  weight  of  the  alkyl  iodide 
formed  increases,  slight  differences  in  manipulation  become 
necessary,  principally  consisting  in  the  employment  of  a  higher 
temperature  to  enable  the  alkyl  iodide  vapours  to  pass  over  \ 
for  which  reason  the  method  is  only  applicable  to  the  lower 
members  of  the  series  and  not  to  compound  ethers  of  the  higher 
alcohols,  such  as  cetylic  alcohol. 


Water 


Water 


Fig.  33. 

The  term  "  methyl  number "  is  conveniently  employed  to 
indicate  the  weight  of  methyl  (OH3  =15)  equivalent  to  the 
silver  iodide  thus  formed  from  1000  parts  by  weight  of  sub- 
stance: if  a  weight  w  milligrammes  of  substance  give  n  milli- 

13 


194  OILS,    FATS,    WAXES,    ETC. 

grammes  of  silver  iodide  (equivalent  to  n  x  -     -    milligrammes 

liOO 

of  CH3)    the    methyl   number,    M,  is    obviously    given   by  the 
equation  — 

AT        n          15,000 
M  •==  -     x       rt-_ 
w  235 

=  -    x    63-83 

M; 

Thus,   296'3    milligrammes    of  oil    of  cloves    gave    373-7    milli- 

*>'""•>    " 

grammes  of  silver  iodide,   whence   M  =  ]r      '•   x  63-83  =  80-5. 

*2i\J\)'d 

The  theoretical  methyl  number  for  pure  eugenof,  C10Hr,O0,  or 
C.jH5  .  C6H3  <^  Q    pjT-   is  91  '5  ;  whence  the  sample  examined  con- 

tained Q  •-     =  87'9  percent,  of  eugenol.     Similarly,  a  sample  of 
y  A  "o 

anise  oil    gave    the    methyl   number  82'8  ;    since   pure   anethol, 
03H5  .  06H4  .  0  .  CH3,  corresponds  with  the  methyl  number  101-4, 

82-8 
the  sample  contained  77-7  =  81*6  per  cent,  of  anethol. 


The  results  of  the  various  quantitative  tests  above  described 
may  be  conveniently  tabulated  as  follows  :  —  • 


L—  VALUES  RECKONED  PER  1,000  PARTS  OF  OIL, 
FAT,  OR  WAX,  &c.,  EXAMINED,  OR  DEDUCED 
FROM  FIGURES  THUS  CALCULATED. 

Total  acid  number  =  Saponification  number  —  Koettstorfer 
number  =  Total  acid  potash  permillage  (  Verseifungszahl). 

The  weight  of  potash  (KOH  =  56-1)  requisite  to  saponify 
completely  1,000  parts  by  weight  of  substance,  including  that 
neutralised  by  any  free  acids  present. 

Saponification  Equivalent.  —  The  number  of  milligrammes  of 
substance  capable  of  furnishing  on  saponificatioii  fatty  acids 
sufficient  to  neutralise  1  c.c.  of  normal  alkaline  solution  (con- 
taining or  equivalent  to  56'1  milligrammes  of  potash,  KOH)  ; 
any  free  fatty  acids  present  being  also  included.  When  the 
total  acid  number  is  K,  the  sponification  equivalent,  E,  is  given 
by  the  equation 

50,100 


Free  acid  number  =  Free  acid  potash  permillage  (Saiirezahl). 
The  weight  of  potash  (KOH  =  56-1)  requisite  to  neutralise  the 


RESULTS    OF    QUANTITATIVE    TESTS.  195 

free  acids  present  in  1,000  parts  by  weight  of  substance.  If  K 
be  the  total  acid  number,  and  A  the  free  acid  number,  then 
j^  • 

-^   x   100  represents  the  proportion  of  free  acids  present  per  100 

of  total  acids,  assuming  the  mean  equivalent  to  be  the  same  in 
each  case. 

Ester  number  =  Compound  ether  potash  permillage  (jEtlierzahl ; 
EsterzaliT).  The  difference  between  the  total  acid  number  and 
the  free  acid  number,  or  value  of  K  -  A ;  expressing  the  weight 
of  potash  (KOH  =  56'1)  requisite  to  neutralise  the  acids  formed 
by  the  saponification  of  the  compound  ethers,  glycerides,  &c., 
present  in  1,000  parts  of  substance. 

The  yield  of  glycerol,  theoretically  obtainable  from  an  oil  or 
fat  consisting  of  triglycerides  (with  more  or  less  free  fatty 
acids),  is  0'05466  x  S  per  cent.,  where  S  is  the  ester  number 
=  K  -  A. 

Insoluble  acid  number  =  insoluble  acid  potash  permillage. 
The  weight  of  potash  (KOH  =  56*1)  required  to  neutralise  the 
fatty  acids,  insoluble  in  boiling  water,  obtained  from  1,000  parts 
of  substance. 

This  figure  must  not  be  confounded  with  the  "  Hehner 
number  "  (Nekner'sche  Zahl)  expressing  the  percentage  (not  per- 
millage) of  insoluble  acids  yielded  by  the  substance. 

Soluble  acid  number  =  soluble  acid  potash  permillage.  The 
weight  of  potash  (KOH  =  56 -1)  required  to  neutralise  the  fatty 
acids,  soluble  in  boiling  water,  obtained  from  1,000  parts  of 
substance. 

Obviously  the  total  acid  number,  K,  =  the  sum  of  the  insoluble 
acid  number  and  the  soluble  acid  number.  In  practice,  the 
soluble  acid  number  is  usually  best  determined  by  subtracting 
the  insoluble  acid  number  from  the  total  acid  number  (p.  168) — 
i.e.,  the  soluble  acid  number  is  K  —  N,  where  N  is  the  insoluble 
acid  number. 

Volatile  acid  number  —  volatile  acid  potash  permillage.  The 
weight  of  potash  (KOH  =  56'1)  requisite  to  neutralise  the  vola- 
tile fatty  acids  obtained  from  1,000  parts  of  substance. 

The  Reichert  number  (Reiclierf sche  Zahl}  being  the  number  of 
c.c.  of  decinormal  alkali  required  to  neutralise  the  volatile  acids 
obtained  from  2*5  grammes  of  substance  by  employing  the 
particular  mode  of  operating  described  by  Reichert  (p.  173),  if  n 
be  the  Reichert  number,  the  corresponding  "  volatile  acid  potash 

permillage"  will  be  n  x  ^— -  =  n  x  2-244.     This  value  is  neces- 

lJ'0 

sarily  somewhat  below  the  true  "  volatile  acid  number"  obtain- 
able by  continuing  the  distillation  until  the  whole  of  the 
volatile  acids  have  passed  over. 

If  Meissl's  modification  .of  the  Reichert  test  be  employed 
(p.  174),  5  grammes  of  substance  being  taken  instead  of  2*5,  if 


196  OILS,    FATS,    WAXES,    ETC. 

m  be  the  Reichert-Meissl  number  (Reichert-MeissVsche  Zahl),  the 
corresponding  volatile  acid  potash  permillage  will  be  m  x  1-122  ; 
as  before  this  value  will  be  below  that  corresponding  with  the 
total  amount  of  volatile  acids  present. 

If  K  be  the  "  total  acid  number,"  and  V  the  "  volatile  acid 

y 
number,"  then  •   -  x   100  represents  the  percentage  of  volatile 

iv 

acids  (expressed  in  terms  of  some  given  acid)  reckoned  per  100 
of  total  acids  present  free  and  combined  as  glycerides,  &c., 
(similarly  expressed) — i.e.,  the  percentage  of  acids  that  are  vola- 
tile, reckoned  on  the  sum  of  the  volatile  and  nonvolatile  acids, 
and  assuming  these  to  have  the  same  equivalent  weight. 

Methyl  N^lmber. — The  weight  of  methyl  (CH3  =15)  equivalent 
to  the  silver  iodide  formed  from  the  alkyl  iodide  vapours  evolved 
on  heating  1,000  parts  by  weight  of  substance  with  hydriodic 
acid. 


II.— VALUES  RECKONED  PER  100  PARTS  OF  OIL, 
FAT,  OR  WAX,  &c.,  EXAMINED. 

Iodine  number  =  iodine  percentage  =  Hiibl  number  (lodzald}. 
The  maximum  weight  of  iodine  capable  of  combining  with  100 
parts  of  substance ;  or  the  weight  of  iodine  equivalent  to  the 
sum  of  the  chlorine  and  iodine  (or  bromine  and  iodine)  requisite 
to  saturate  100  parts  of  substance. 

Hehner  number  =  Ifehner'sche  Zald.  The  weight  of  fatty  acids 
insoluble  in  boiling  water  yielded  by  100  parts  of  substance. 


III.— VALUES  RECKONED  PER  1,000  PARTS  OF  THE 
FREE  FATTY  ACIDS  FORMED  ON  SAPONIFI- 
CATION,  OR  DEDUCED  FROM  FIGURES  THUS 
CALCULATED. 

Fatty  acid  neutralisation  number  =  potash  permillage  requisite 
for  neutralisation  of  mixed  free  fatty  acids,  reckoned  per  1,000 
parts  of  fatty  acids  (  Verseifungszahl  der  Fettsailren).  The  weight 
of  potash  (KOH  =  56'1)  required  to  neutralise  1,000  parts  of 
the  mixed  fatty  acids  obtained  by  saponification  of  a,  fat  or  oil, 
&c.,  and  separation  of  fatty  acids  from  the  resulting  soap. 

Mean  Equivalent  of  the  Fatty  Acids. — The  number  of  milli- 
grammes of  mixed  fatty  acids  requisite  to  neutralise  1  c.c.  of 
normal  alkaline  solution  (containing  or  equivalent  to  56-1  milli- 
grammes of  potash,  KOH).  If  N  be  the  neutralisation  number, 
the  mean  equivalent  F  is  given  by  the  equation 

_  56,100 

N    ' 


RESULTS    OF    QUANTITATIVE    TESTS.  197 

In  the  case  of  an  oil,  &c.,  consisting  wholly  of  triglycerides 
(i.e.,  where  the  free  acid  number  is  so  small  as  to  be  negligible), 
the  saponificatioii  equivalent  of  the  oil,  E,  and  the  mean  equi- 
valent of  the  fatty  acids  obtainable  therefrom,  F,  are  related 
thus — 

E  =  F  +  12-67. 

If,  however,  the  oil  contain  free  acids  in  measurable  quantity  the 
relationship  is 

E  =  F  +  1  x  12'67' 

where  S  is  the  ester  number  and  K  the  total  acid  number  of 
the  oil. 

The  fatty  acid  neutralisation  number,  N,  and  the  total  acid 
number  of  the  original  oil,  K,  are  related  thus — 

»-•* 


IV.    VALUES    RECKONED    PER    100   PARTS  OF  FREE 
FATTY  ACIDS  FORMED  ON  SAPONIFICATION. 

Iodine  Number  of  Free  Fatty  Acids  (lodzahl  der  Fettsaureri). 
—  The  maximum  weight  of  iodine  (or  iodine  equivalent  to  the 
sum  of  chlorine  and  iodine  or  bromine  and  iodine)  capable  of 
combining  with  100  parts  of  free  fatty  acids. 

If  I  be  the  iodine  number  of  the  original  oil,  &c.,  and  I'  that 
of  the  fatty  acids  thence  obtained,  then 


In  the  case  of  an  oil,  &c.,  consisting  substantially  of  tri- 
glycerides, so  that  E  =  F  +  12-67,  and  where  the  mean  equi- 
valent of  the  free  fatty  acids  lies  between  250  and  330,  the 

F 

value  of  „   lies   between    1*0507   and    1-0384  —  i.e..   the    iodine 
.b 

number  of  the  fatty  acids  exceeds  that  of  the  original   oil  by 
close  to  4*5  per  cent,  of  the  latter  value. 


V.  VALUES  RECKONED  PER  1,000  PARTS  OF 
PRODUCT  OF  ACETYLATION  OF  FREE  FATTY  ACIDS. 

Acetyl  Number  =  Acetyl  potash  permillage  (Acetylzahl}. — The 
weight  of  potash  (KOH  =  56 -1)  neutralised  by  the  acetic  acid 
formed  on  saponification  of  1,000  parts  of  the  productof  the 
action  of  acetic  anhydride  on  the 


108  OILS,    FATS,    WAXES,    ETC. 

The  acetyl  number  as  thus  defined  includes  both  the  titratioii 
value  obtained  by  Benedikt  and  Ulzer,  conveniently  referred  to 
as  the  titration  acetyl  number  ;  and  the  result  of  applying  the 
distillation  process  so  as  to  separate  acetic  acid,  as  proposed  by 
Lewkowitsch,  conveniently  distinguished  as  the  distillation  acetyl 
number.  Like  the  volatile  acid  number,  this  latter  value  is 
always  apt  to  be  more  or  less  erroneous  in  defect  on  account  of 
the  difficulty  of  distilling  off  and  titrating  every  trace  of  acetic 
acid. 

On  the  other  hand,  in  the  case  of  free  fatty  acids  very  little 
dependence  can  be  placed  on  the  former  number,  although  for 
alcoholiform  substances  this  objection  does  not  apply. 


EARLIER  FORMS  OF  PRESS.  199 


4.  Processes  Used  for  Extracting,  Rendering, 
Refining,  and  Bleaching  Oils,  Fats,  &c. 


CHAPTER  IX. 

EXTRACTION  OF  OILS  FROM  SEEDS,  &e.,  BY 
PRESSURE  OR  SOLVENTS. 

EARLIER    FORMS    OF    PRESS. 

THE  use  of  olives  and  various  kinds  of  seeds  and  nuts  as  sources 
of  oil  has  been  known  from  at  least  the  commencement  of  the 
historic  period,  the  earliest  appliances  for  the  expression  of  the 
fluid  consisting  of  "  mills  "  somewhat  after  the  fashion  of  the 
primeval  corn  grinding  hand  mills,  where  a  rounded  stone  was 
made  to  revolve  in  a  basin  shaped  stone  vessel  by  means  of 
projecting  handles,  worked  usually  by  two  women  seated  on  the 
ground  on  opposite  sides  of  the  mill ;  *  the  pulp  thus  produced 
was  then  placed  in  sacking  and  pressed  by  means  of  planks 
weighted  with  stones,  very  much  as  grape  juice  was  expressed 
in  the  earliest  forms  of  wine  press  ;  or  a  powerful  lever  was 
applied,  somewhat  after  the  style  of  an  enormous  lemon  squeezer. 
Yarious  forms  of  lever  press  have  been  in  use  at  different  times, 
some  of  more  complex  order  than  the  simple  lemon  squeezer  type 
of  machine,  a  bent  lever  working  a  cam  pressing  upon  the  upper 
board  so  as  to  force  it  downwards  ;  or  the  pressure  board  being 
arranged  vertically,  and  the  sacking  being  compressed  between 
it  and  a  stout  vertical  standard,  such  as  the  stump  of  a  tree. 
Double  action  presses  of  this  kind,  working  alternately,  have  also 
been  constructed.  A  further  improvement  in  oil  pressing  appli- 
ances was  the  introduction  of  wedges  between  the  pressure 
boards,  actuated  by  levers  and  cams  or  by  percussion ;  in  the 
latter  case,  the  press  consisted  of  a  stout  framework  of  beams, 
inside  of  which  the  pressure  boards  and  seed  bags  were  arranged, 
so  that  by  hammering  in  wedges  between  adjacent  pairs  of 
boards,  or  between  the  boards  and  the  framework,  the  seed  bags 
were  gradually  compressed  and  finally  subjected  to  considerable 

*  "  There  shall  be  two  women  grinding  together  ;  the  one  shall  be  taken, 
and  the  other  shall  be  left." — Luke  xvii.  35. 


200  OILS,    FATS,    WAXES,    ETC. 

pressure.  Even  at  the  present  day  lever  presses  and  wedge 
presses  of  a  more  or  less  rude  manufacture,  but  of  considerable 
practical  efficiency,  are  still  in  use  to  a  considerable  extent 
amongst  those  nations  and  in  those  districts  to  which  improved 
machinery  and  engineering  appliances  have  not  yet  penetrated — 
e.g.]  in  China  and  some  parts  of  Japan* — whilst  improved  modifi- 
cations of  the  older  lever  press,  constructed  with  elbow  levers 
actuated  by  steam  or  water  power,  are  employed  with  advantage 
for  various  oil  and  grease  expression  purposes  (p.  202). 

Screw  presses  have  also  been  extensively  used,  and  are  still 
largely  employed  in  the  smaller  factories ;  but  of  late  years 
they  have  been  mostly  superseded  by  hydraulic  presses  in  the 
larger  and  more  modern  seed  oil  mills.  In  similar  fashion 
various  forms  of  appliances  have  been  successively  introduced 
and  used  for  the  crushing  of  oleiferous  material,  and  otherwise 
treating  it  previously  to  expression,  so  as  to  render  the  flow  of 
oil  more  easy  and  complete ;  thus  pairs  of  crushing  rollers 
working  on  parallel  axes  so  as  to  squeeze  the  olives,  seeds,  &c., 
introduced  between  them,  and  "  edge  runners "  (Fig.  48) 
arranged  like  a  mortarmill,  are  more  recent  developments  which 
have,  for  the  most  part,  superseded  the  older  form  of  "  stamps  " 
where  mechanically  worked  pestles  pounded  the  seed,  &c.,  to  be 
crushed  in  large  basins  or  mortars. 

Even  at  the  present .  day  a  considerable  amount  of  oil  of 
various  kinds  is  manufactured  (on  the  small  scale)  by  a  process 
probably  of  greater  antiquity  still  than  any  mechanical  expres- 
sion method.  In  most  tropical  and  subtropical  countries  oleifer- 
ous seeds  and  nuts  of  various  kinds  abound ;  in  order  to  extract 
the  oil  these  are  simply  pounded  or  crushed  and  then  boiled  with 
water,  the  oil  rising  to  the  top  and  being  skimmed  off.  Experi- 
ence has  generally  guided  the  natives  to  the  use  of  a  previous 
roasting  of  the  nuts  or  beans,  the  effect  of  the  heat  being  to 
coagulate  and  solidify  mucilaginous  and  albuminous  matter, 
rendering  the  after  separation  of  the  oil  by  means  of  water 
much  more  easy  and  complete.  Castor  oil,  for  example,  is  thus 
largely  extracted  for  local  use  in  India ;  palm  oil  and  palmnut 
oil,  until  comparatively  recently,  were  almost  wholly  prepared 
by  this  method,  all  the  oil  shipped  from  Africa  having  been 
extracted  by  a  water-boiling  process  applied  to  the  pulp  and 
roasted  kernels ;  of  late  years,  however,  it  has  been  more  usual 
to  separate  the  kernels  from  the  pulp  and  export  them  untreated, 
the  oil  being  subsequently  extracted  by  the  ordinary  expression 
or  solvent  processes. 

In  the  rural  olive  producing  districts  a  considerable  amount 
of  oil  is  prepared  by  a  sort  of  combination  of  the  two  methods, 

*  For  a  description  of  a  peculiar  form  of  wedge  press  used  in  Formosa  for 
the  extraction  of  olive  oil,  see  Report  by  Consul  Warren  on  the  trade  of 
Taiwan,  Journal  Soc.  Chem.  Industry,  1S91,  p.  556. 


HOT   WATER    PROCESSES.  201 

the  appliances  being  somewhat  rude  and  primeval  in  the  smaller 
oil  factories,  but  more  modern  in  the  larger  ones.  The  crushed 
pulp  is  washed  by  agitation  with  water,  the  oil  as  it  separates 
from  the  husks  and  rises  to  the  top  running  off  along  with  water 
to  separation  tanks  ;  the  residual  wet  oil-containing  husks  are 
strained  and  boiled  down  to  a  kind  of  porridge  or  soft  pulpy 
dough,  and  the  oil  mixed  with  water  then  separated  by  pressure 
in  some  sort  of  rough  screwpress.  In  some  cases  the  resulting 
marc  is  ground  up  again  by  heavy  edgerunners  of  granite,  &c. 
(worked  by  water  or  cattle  power),  boiled  up  afresh  with  water, 
and  subjected  to  further  pressing.* 

A  somewhat  analogous  process  is  sometimes  used  in  the 
extraction  of  the  fat  or  "  butter  "  of  the  tallow  tree  (Stillingia, 
sebifera),  and  other  vegetable  semisolid  oils  or  fats  ;  the  crushed 
seeds,  nuts,  etc.,  are  placed  in  wicker  or  bamboo  baskets,  weighted 
with  stones  under  boiling  water,  so  that  the  melted  fat  gradually 
separates  and  rises  to  the  top ;  the  remaining  oil  is  then- 
extracted  by  pressure  applied  to  the  still  hot  material.  This 
method  is  more  particularly  suited  to  those  nuts,  ttc.,  where  the 
kernel  is  surrounded  with  a  highly  oleaginous  pericarp,  which  is. 
thus  melted  away  by  a  process  closely  akin  to  that  whereby 
animal  fats  are  "  rendered  "  by  means  of  steam  or  boiling  water 
(vide  Chap,  x.)  Processes  closely  analogous  in  general  character 
are  in  use  in  various  countries  for  the  extraction  of  oil  from  fish 
of  various  kinds  (e.g.,  sardines),  and  from  fish  and  shark  livers, 
whilst  the  mode  of  preparation  of  most  kinds  of  wax  is  very 
similar ;  thus  in  the  case  of  Chinese  wax  (Peh-Ia),  the  insect 
producing  the  wax  is  a  species  of  coccus  (possibly  several  different 
species),  the  young  brood  of  which  sticks  to,  and  punctures  the 
bark  and  twigs  of  the  trees  (Fraxinus  chinensis,  Liyustrum 
lucidum,  &c.,)  selected  as  domicile.  A  waxy  material  is  secreted  f 
covering  the  bark,  in  which  the  insects  ultimately  imbed  them- 
selves, forming  chrysalides.  To  obtain  the  wax,  the  branches 
are  scraped,  some  of  the  cocoons  being  reserved  for  breeding,  the 
rearing  of  the  insects  being  a  special  industry  like  silk  growing  ; 
the  scrapings  are  heated  with  boiling  water  so  as  to  melt  off  the 
waxy  matter,  which  is  separated  by  skimming  from  the  dirt,  dead 
insects,  &c. 

The  different  kinds  of  vegetable  wax  (myrtle  wax,  Japanese 
wax,  carnauba  wax,  <tc.),  are  mostly  obtained  by  similarly  treat- 
ing with  boiling  water  the  berries,  bark,  £c.,  in  or  on  which 
the  material  is  naturally  secreted  or  deposited,  and  separating 
the  melted  wax  as  it  rises.  Bees'  combs,  &c.,  are  similarly 

*  Descriptions  of  the  appliances  in  use  in  the  Maritime  Alps  and  in 
Southern  Sicily  for  the  preparation  of  olive  oil  are  given  in  the  Journal 
Soc.  Arts.,  Nov.  20,  1891,  and  June  16,  1893. 

t  As  with  beeswax,  opinions  differ  somewhat  as  to  how  far  the  wax  is 
precontained  in  the  sap  of  the  trees  serving  as  food,  and  how  far  it  is  formed 
or  altered  by  animal  life  action. 


202 


OILS,    FATS,    WAXES,    ETC. 


treated    to   obtain    beeswax,    and    separate    it    from    adherent 
honey  and  solid  impurities. 

Elbow  Press. — Although  the  older  rude  forms  of  lever  press 
and  wedge  press  are  rapidly  being  superseded  by  more  modern 
devices,  more  especially  by  hydraulic  pressure,  they  are  still  by 
110  means  extinct  amongst  those  peoples  where  advancing 


Fig.  31.— Elbow  Press. 

civilisation  has  not  yet  entirely  improved  away  the  ancient 
methods  and  customs,  whilst  improved  machines  of  these  classes 
are  still  in  active  use  to  some  extent  even  in  Europe  and 
America.  Fig.  34  represents  a  form  of  "  elbow  press,"  largely 
used  in  the  United  States  for  expressing  hot  melted  tallow,  &c., 
from  animal  adipose  tissue.  As  the  screw  is  worked  (by  hand 


WEDGE    PRESS. 


203 


wheel  or  band  and  pulley)  the  two  powerful  elbows  are 
straightened,  and  the  ram  depressed  ;  owing  to  the  mechanical 
nature  of  the  action,  the  pressure  is  automatically  increased 
towards  the  end  of  the  operation  as  the  elbows  straighten. 

Wedge  Press. — An  improved  form  of  wedge  press  is  repre- 
sented by  Figs.  35  and  36  (from  Schtidler)  in  front  and  side 
elevation,  Fig.  37  indicating  the  longitudinal  section  of  the  lower 
portion.  Inside  each  of  a  pair  of  troughs,  J  J,  is  placed  an 
arranges e:it  of  wooden  wedges  and  planking,  B  L  S  K  B, 


Press — Front  and  Side  Elevation. 


together  with  two  bags  containing  the  crushed  seed,  ttc.,  to  be 
expressed,  O  O,  each  enclosed  between  cast  iron  frames,  T  P.  The 
"  loose -wedges,"  L  L,  are  suspended  by  ropes,  and  serve  to  lock 
the  whole  arrangement  together,  the  loosening  when  the  pressure 
is  completed  being  effected  by  casting  off  the  ropes  and  allowing 
the  suspended  vertical  beams,  C  C,  to  descend,  pile-driver  fashion, 
so  as  to  drive  these  wedges,  L  L,  down ;  A  A,  B  B  represent  a 
stout  timber  frame  supporting  the  driving  beams.  The  pressure 
is  obtained  by  similarly  forcing  downwards  the  "press-wedges," 


204 


OILS,    FATS,    WAXES,    ETC. 


K  K,  by  the  beam  drivers,  D  D.  These  drivers  are  raised  by 
means  of  stout  teeth,  G,  projecting  from  a  horizontal  axle  work- 
ing on  studs,  E  and  F,  attached  to  the  beams  respectively,  a 
system  of  ropes,  b,  c,  bent  lever,  a,  and  studs,  d,  d,  being  attached, 
so  that  when  the  ropes  are  pulled,  either  of  the  drivers  can  at 
will  be  raised  so  as  to  bring  it  out  of  the  reach  of  the  teeth,  and 
keep  it  suspended  out  of  action.  The  oil  bag,  being  placed  in 
position  between  the  plates,  T  P,  of  the  iron  frames,  L,  is  adjusted 
at  a  convenient  height  by  means  of  the  attached  rope.  The 
drivers,  D,  being  then  set  in  action,  the  press  wedge,  K,  is 
forced  down,  and  the  oil  bag  consequently  strongly  compressed. 
When  the  oil  ceases  to  run  and  the  wedge  is  driven  home,  D  is 
thrown  out  of  action  and  C  allowed  to  hammer  on  the  loose 
wedge  (the  rope  attached  being  slackened)  ;  the  loose  wedge,  L, 
soon  falls,  and  the  bags  with  exhausted  oilcake  are  then  removed 
and  fresh  ones  substituted. 


Fig.  37. — Wedge  Press— Longitudinal  Section  of  Lower  Portion. 

In  some  of  the  Marseilles  oil  factories  an  arrangement  is  in 
use  known  as  the  "  Estrayer  Cylinder,"*  the  action  of  which  is 
somewhat  akin  to  that  of  the  wedge  press.  The  apparatus  con- 
sists of  two  cylinders,  one  inside  the  other,  of  which  the  outer 
acts  upon  the  inner  by  means  of  a  series  of  inclined  planes,  the 
inner  cylinder  being  composed  of  eight  segments  which  either 
close  up  tightly  or  separate  slightly  according  as  pressure  is 
exercised  or  removed  by  the  position  of  the  outer  cylinder. 
Screens  made  of  esparto  grass  and  horsehair  are  employed 
instead  of  oilbags  of  the  same  material  ("scourtins  ")  such  as 
are  employed  in  other  forms  of  press  ;  these  are  subject  to  much 
less  wear  and  tear  than  the  scourtins,  whereby  an  economy  of 
80  to  90  per  cent,  in  the  cost  of  the  scourtins  is  effected.  An 

*Jonm.  Soc.  Chcm.  Ind.,  1893,  p.  49. 


SCREW    PRESS. 


205 


interior  movement  allows  of  the  cylinder  being  enlarged  in 
diameter,  so  that  the  cakes  can  be  readily  removed.  The  appa- 
ratus will  withstand  a  pressure  of  500  kilos  per  square  centimetre 
(63^  cwts.  per  square  inch) ;  half  of  this  is  as  much  as  can  be 
safely  applied  to  the  ordinary  bags  without  great  risk  of  bursting 
them.  A  cylinder  holding  80  to  100  kilos  of  seeds  can  be  dis- 
charged and  refilled  in  7  to  8  minutes,  the  pressing  occupying 
30  to  35  minutes. 


Fig.  38. 

Screw  Press. — In  districts  where  more  modern  machinery 
has  not  been  extensively  adopted  (e.g.  many  parts  of  Spain, 
China,  West  Indies,  South  America,  Africa,  &c.),  rude  screw 
presses  are  still  largely  in  use  in  the  comparatively  small  oil 
mills  where  oil  is  expressed  in  much  the  same  fashion  as  has 
been  practised  for  centuries ;  these  mostly  work  on  the  principle 


206 


OILS,    FATS,    WAXES,    ETC. 


of  an  ordinary  copying  press,  the  sacking  (or  wicker  or  straw 
basketing,  &c.)  containing  the  material  to  be  expressed  being 
placed  between  the  two  plates  of  the  press,  and  the  screw  (fre- 
quently of  wood)  turned  by  means  of  a  long  lever  so  as  to  bring 
the  plates  nearer  together  and  express  the  oil,  much  as  a  wet 


sponge  would  be  squeezed  in 
handle. 


copying  press   by  turning  the 


Fig.  39. 

Fig.  38  represents  an  English  improved  form  of  screw  press 
for  expressing  oil,  tfec.,  from  fish  or  similar  materials  where  only 
a  moderate  pressure  is  required.  Motion  is  communicated  by 


HYDRAULIC    PRESS.  207 

belts  from  shafting  to  a  horizontal  axle  carrying  a  worm  which 
gears  into  a  toothed  wheel,  the  revolution  of  which  raises  or 
depresses  the  screw  passing  concentrically  through  the  wheel, 
and  consequently  elevates  or  lowers  the  plunger.  According  as 
a  straight  belt  is  used  connected  with  one  pair  of  fast  and  loose 
pulleys  on  the  axle,  or  a  crossed  belt  connected  with  the  other 
pair,  the  plunger  moves  in  one  direction  or  the  other.  The 
material  to  be  pressed  is  placed  in  bags  between  loose  metal 
plates,  the  press  itself  being  enclosed  in  a  wrought  iron  steam 
casing  (stayed  to  resist  pressure)  provided  with  a  steam-heated 
door  of  similar  construction,  so  that  when  requisite  the  temper- 
ature inside  the  press  can  be  elevated  up  to  that  of  the  steam  or 
nearly  so. 

Fig.  39  represents  a  screw  press  of  German  make.  The  mate- 
rial to  be  expressed  is  placed  inside  the  perforated  cylinder  B, 
Avhich  is  then  placed  inside  the  cylinder,  C,  and  mounted  011  the 
platform,  A  ;  the  ram,  D,  attached  to  the  screw,  F  F,  being  raised 
to  a  convenient  height.  On  turning  the  horizontal  wheel,  G,  the 
screw  and  ram  descend  and  the  material  is  strongly  compressed 
in  the  inner  cylinder.  The  expressed  liquid  passes  through  the 
perforations  in  the  walls  of  B  and  runs  out  through  others  at  the 
base  of  C  into  a  circular  groove  in  the  platform,  A,  and  thence 
by  the  spout  to  a  vessel  placed  to  receive  it.  A  small  hydraulic 
arrangement  is  attached  at  the  base,  such  that  by  turning  the 
handle,  E,  a  piston  is  screwed  slowly  inwards,  thus  raising  a 
hydraulic  ram  on  to  the  top  of  which  the  platform,  A,  is  fixed, 
and  so  obtaining  at  the  end  of  the  operation  a  more  powerful 
pressure  than  would  be  possible  by  means  of  the  screw,  F  F,  alone. 

Hydraulic  Press. — The  ordinary  form  of  hydraulic  press  as- 
adapted  for  oil  expression  consists  of  a  ram  raised  by  admission 
of  water  into  its  cylinder,  either  intermittently  by  pumps  (worked 
by  hand  or  power)  or  continuously  from  an  accumulator.  The 
former  method  is  preferred  for  many  purposes,  since  the  pulsating 
pressure  obtained  by  means  of  a  pump  appears  to  be  better 
adapted  for  the  expression  of  oil  from  most  kinds  of  seeds,  &c., 
than  the  continuous  steady  pressure  of  an  accumulator.  Presses 
in  which  the  ram  works  horizontally  instead  of  vertically  are 
sometimes  preferred.  Fig.  40  represents  a  German  form  of 
hydraulic  press,  empty  before  charging,  and  Fig.  41  the  same 
after  the  ram  has  risen.  The  bags  are  placed  in  the  cavities  of 
the  shelves  or  press  boxes,  E  E  E,  and  the  ram  started  working. 
As  it  rises  each  bag  is  strongly  compressed  between  the  base  of 
the  press  box  containing  it  and  the  projecting  lower  portion  of 
the  box  next  above  it ;  the  oil  runs  out  into  the  circular  grooves, 
F  F,  and  thence  to  delivery  spouts,  J  J,  and  so  through  the  pipes,, 
G  G,  to  the  vertical  oil  shoot,  H,  leading  to  the  oil  well  or  tank^ 
The  headpiece  of  the  press,  C,  is  supported  by  stout  pillars,  D  D,, 
to  resist  the  strain. 


208  OILS,    FATS,    WAXES,    ETC. 


Fig.  40. —Hydraulic  Press  (German  Form). 


HYDRAULIC   PRESS. 


209 


Fig.  41, 


210 


OILS,    FATS,    WAXES,    ETC. 


Fig.  42  represents  an  English  handworked  hydraulic  press, 
specially  suitable  for  light  work  such  as  that  in  a  small  olive  oil 
mill.  The  press  being  filled,  the  larger  of  two  differently  sized 
pumps  attached  to  it  is  worked  by  means  of  the  detachable  lever 
handle,  until  the  bulk  of  the  oil  is  expressed ;  to  obtain  a 
stronger  pressure  for  the  extraction  of  the  remainder,  the  lever 


Fig.  42. 

handle  is  then  applied  to  a  second  smaller  pump  arranged  by 
the  side  of  the  first  one,  whereby  a  considerable  increment  in 
power  is  obtained. 

Fig.  43  represents  a  press  arranged  for  working  on  the  "Anglo- 
American  System  "  (vide  infra).  The  plates  are  corrugated,  and 
arranged  at  such  distances  apart  as  just  to  allow  of  the  moulded 
cakes  of  hot  ground  seed,  &c.,  from  the  kettle  and  moulding 


HYDRAULIC    PRESS. 


211 


machine  (p.  221)  being  introduced,  preferably  from  each  opposite 
side  alternately.  Usually  sixteen  cakes  are  pressed  simultaneously 
in  one  press,  whilst  four  such  presses  are  worked  together  in  one 
block,  all  four  being  erected  inside  the  same  wrought  iron  oil 
tank,  which  serves  as  a  foundation  and  collects  the  expressed 
oil  in  a  most  efficient  man- 
ner. The  pressure  employed 
usually  rises  from  700  or  800 
Ibs.  per  square  inch  at  first 
up  to  2  tons  at  the  end. 
Fig.  44  represents  the  plan 
and  longitudinal  section  of 
one  of  the  press  plates,  Fig. 
45  indicating  the  cross-sec- 
tion. 

The  dimensions  of  the  oil- 
cakes produced  vary  con- 
siderably with  the  size  of 
the  oil  mill,  the  system  of 
working,  and  the  nature  of 
the  seed,  £c.,  used ;  the 
cakes  are  always  made  to 
taper  somewhat  so  as  to 
facilitate  withdrawal  from 
the  cake  boxes.  Thus  with 
the  smallest  mills  the  cakes 
may  weigh  about  3  Ibs.,  and 
the  dimensions  may  be  14 
inches  long,  and  6i-  inches 
wide  at  one  end  and  5|  at 
the  other,  the  press  being 
constructed  to  take  from  4 
to  6  such  cakes  at  a  time ; 
whilst  with  somewhat  larger 
mills  the  cakes  may  weigh 
about  4  Ibs.,  being  20  inches 
long,  and  1\  wide  at  one  end 
by  5J  at  the  other.  Still 
larger  cakes  (up  to  some  30  inches  long,  and  10  or  11  wide  at  one 
end  and  7  or  8  at  the  other)  are  made  in  mills  of  greater  magnitude 
(especially  when  working  linseed),  where  the  scale  of  manufacture 
is  large  enough  to  enable  full-sized  presses,  <fec.,  to  be  employed. 
Such  a  linseed  cake  generally  weighs  from  6  to  13  Ibs.,  averaging 
about  8  or  9  Ibs.,  varying  with  the  source  and  richness  in  oil  of 
the  seed  used ;  the  weight  of  the  pressed  oilcake  obtained  from 
a  given  quantity  of  seed  is  obviously  the  less  the  larger  the  yield 
of  oil.  When  working  on  the  older  system  the  press  usually 
contains  only  four  cake  boxes,  three  such 


j 


UNIVERSITY 


212 


OILS,    FATS,    WAXES,    ETC. 


by  one  man  and  a  boy,  including  paring  and  storing  the  cakes ; 
the  presses  are  charged  from  three  to  six  times  an  hour,  accord- 
ing to  the  seed  used  (cotton  seed  about  four  times,  linseed  five). 
With  some  kinds  of  seed  (e.g.,  rape  and  gingelly)  the  crushed 
seed  is  worked  over  twice,  two  presses  being  employed  for  the 
first^  expression  and  three  for  the  second — the  press  cake  pro- 


n 


Fig.  44. 

duced  by  the  first  treatment  being  reground  before  the  second 
expression,  usually  by  means  of  edge  runners  (p.  219).  Seeds 
less  rich  in  oil  than  linseed  and  cotton  seed  yield  proportionately 
heavier  cakes  for  the  same  weight  of  seed ;  as  a  rule,  with  the 
less  oleaginous  seeds,  &c.,  a  better  yield  is  obtained  by  pressing 
proportionately  smaller  quantities  at  a  time,  so  as  to  form  in  all 
cases  oilcakes  of  about  the  same  thickness. 


Fig.  45. 

With  certain  kinds  of  seeds  furnishing  "  salad  "  oils  of  finest 
character,  the  expression  is  carried  out  in  three  stages  : — First 
of  all  cold  pressure  is  applied  to  a  moderate  extent,  whereby  a 
"  cold-drawn  "  oil  is  obtained  of  the  purest  quality  (after  refining, 
i.e.,  removal  of  mucilage,  &c.).  Then  the  cake  is  again  ground, 
slightly  moistened  with  water,  and  pressed  a  second  time,  using 
somewhat  higher  pressure ;  the  oil  thus  obtained  is  cold-drawn 
oil  of  second  quality.  Finally,  the  cakes  are  again  ground  and 


OILCAKE.  213 

heated  and  pressed  hot ;  the  oil  thus  obtained  is  far  inferior  to 
either  of  the  former  runnings.  The  oilcake  thus  left  often 
retains  a  sufficient  quantity  of  oil  to  render  it  worth  while  to 
treat  by  some  solvent  extraction  process  (p.  231),  whereby  a  still 
lower  grade  of  oil  is  ultimately  obtained.  This  mode  of  treat- 
ment in  several  stages  is  more  especially  adopted  in  the  case  of 
higher  class  edible  oils — such  as  those  from  the  arachis  nut,  and 
from  sunflower  seed ;  or  in  the  production  of  the  more  highly 
priced  oils  used  for  other  purposes— e.g.,  almond  oil.  Coarse  oils, 
such  as  linseed,  are  usually  expressed  but  once,  the  pulp  being 
heated  to  commence  with  as  described  below,  partly  to  render 
the  oil  more  fluid,  and  partly  to  coagulate  albuminous  matter. 
Some  kinds  of  seeds,  however  (e.g.,  sesame  and  rape),  are  gener- 
ally treated  in  two  stages — i.e.,  pressed  twice  successively  so  as  to 
obtain  two  qualities  of  oil.  When  the  cakes  are  removed  from 
the  press,  the  cloths  are  stripped  off  and  the  edges  pared  off; 
the  parings  contain  a  notable  amount  of  oil,  and  are  therefore 
ground  up  and  mixed  with  fresh  crushed  seed  for  another 
batch. 

In  some  cases  mixtures  of  seeds  are  intentionally  prepared  arid 
crushed  and  treated  together ;  in  others  the  seed  as  harvested  is 
a  mixture,  two  or  more  kinds  of  plants  being  grown  together ;  so 
that,  excepting  when  the  seeds  differ  sufficiently  in  size  to  be  capable 
of  separation  by  sifting,  the  oil  ultimately  obtained  is  necessarily 
of  a  mixed  character.  Partly  from  causes  of  this  kind,  and  partly 
on  account  of  subsequent  adulteration,  it  is  difficult,  if  not  impos- 
sible, to  obtain  an  absolutely  pure  oil  of  any  given  kind  in 
commerce,  the  only  practicable  method  of  procuring  a  perfectly 
pure  sample  being  to  hand-pick  the  seeds  and  express  the  oil 
in  a  small  press  kept  for  such  purposes.  Accordingly,  a  small 
press  for  the  purpose  of  preparing  samples  of  genuine  seed  oils 
from  time  to  time  is  an  indispensable  part  of  the  equipment  of 
a  laboratory  where  oil  examinations  are  made  by  comparison  of 
the  substances  tested  with  specimens  of  oils  and  mixtures  of  oils 
known  to  be  themselves  unadulterated. 

Composition  of  Oilcake. — The  analyses  quoted  on  p.  214 
are  given  by  Schadler.as  representing  the  average  composition  of 
oilcakes  of  various  kinds. 

According  to  Yoelcker,  linseed  cake  made  by  the  older  system 
usually  contains  from  below  10  to  about  16  per  cent,  of  oil,  and 
cotton  seed  cake  from  6  per  cent,  (undecorticated)  up  to  16  per 
cent,  (decorticated).  Oilcakes  made  by  the  Anglo-American 
system  of  working  are  usually  more  completely  expressed,  so  as 
to  contain  distinctly  smaller  percentages  of  residual  oily  matter 
than  cakes  prepared  without  the  aid  of  a  moulding  machine.  If, 
however,  the  expression  be  carried  too  far,  the  value  of  the  cake 
as  cattle  fodder  is  greatly  diminished,  so  that  in  extreme  cases  it 
may  be  rendered  unsaleable. 


214 


OILS,    FATS,    WAXES,    ETC. 


Oilcake  from 

Water. 

Cellulose 

Fatfcv         anc*  ^on~ 
ivf  tt  r-       nitrogenous 
Matter.       Vegltable 
!     Matter. 

Ash. 

Proteids. 

Nitrogen. 

Arachis  nuts,    . 

11-50 

8-80    !    31-10 

7-25 

41-35 

6-80 

Cotton  seed, 

13-00 

7'50/    51-00 

8-50 

20-00  * 

2-90 

Rape  seed,   .     . 

10-12 

9-23        41-93 

6-84 

31-88 

5-00 

Colza,      .     .     . 

11-35 

9-00        42-82 

6-28 

30-55 

4-50 

Sesame  seed,     . 

10-35 

10-10 

38-80 

9-80 

31-93 

5-00 

Beechnuts,  .     . 

11-40 

8-50 

49-80 

5-30 

24-00 

3-20 

Linseed,  .     .     . 

10-5(5 

9-83 

44-01 

6-50 

28-50 

4-25 

Cress  seed,  .     . 

12-23 

7-68 

47-00 

12-50 

20-50 

3-00 

Camelina  seed, 

9-60 

9-20 

50-90 

7-00 

23-30 

3-60 

Poppy  seed, 
Sunflower  seed, 

9-50 
10-20 

890 
8-50 

37-67 
48-90 

11-43 
11-40 

32-50          5-00 
21*00          2-40 

Madia,     .     . 

11-86 

7-90 

50-00    I    12-24 

18-00 

2-50 

Hemp  seed, 

10-00 

8-20 

48-00        12-24 

21-50 

3-30 

Palm  kernels,  . 

9-50 

8-43 

40-95 

10-62 

30-40 

4-50 

Cokernuts,  . 

1000 

9-20/ 

40-50  . 

10-50 

30-00  •* 

4-50 

Nordlinger  has  found  (p.  115)  from  6  to  15  per  cent,  of  total 
fatty  matters  contained  in  rape,  poppy,  earthnut,  sesame,  palmnut, 
cokernut,  linseed,  and  castor  bean  cakes ;  of  which  the  free  acids 
constituted  fractions  varying  between  less  than  Ti^  and  above  -£. 

According  to  B.  Dyer,*  linseed  cake,  as  made  at  the  present 
day,  contains,  on  an  average,  about  10  per  cent,  of  oil,  varying 
between  7  and  16  per  cent.;  of  this  a  quantity  varying  between 
one-thirteenth  and  one-fifth,  usually  consists  of  free  fatty  acid, 
the  proportion  being  less  the  purer  the  linseed.  With  some 
freshly  expressed  cakes,  free  acid  is  practically  absent ;  on  the 
other  hand,  with  cakes  that  have  "heated"  on  keeping,  the 
greater  portion  of  the  glycerides  originally  present  is  decom- 
posed, producing  free  fatty  acids.  Obviously,  the  proportion  of 
free  acid  formed  chiefly  depends  on  the  extent  to  which  hydrolytic 
actions  have  taken  place  during  storage. 


OIL  MILL  PLANT. 

The  plant  in  use  in  modern  oil  mills  varies  somewhat  in 
details  according  to  the  nature  of  the  material  to  be  treated,  and 
according  as  the  substance  is  intended  first  to  be  submitted  to  a 
preliminary  cold  pressing  so  as  to  obtain  a  portion  of  the  oil  as  a 
product  of  finer  quality,  and  then  to  hot  pressings  to  obtain  lower 
grades;  or  to  be  treated  hot  at  one  operation  only.  Further, 
the  climate  somewhat  modifies  the  character  of  the  process, 
inasmuch  as  many  substances  can  be  sufficiently  completely 
^expressed  in  a  tropical  climate,  without  any  extraneous  heat 

*  Journ.  Sec.  Ckem.  Ind.,  1893,  p.  8. 


OIL    MILL    PLANT.  215 

being  requisite,  that  would  require  to  be  artificially  warmed  in  a 
colder  climate  to  render  the  oil  sufficiently  fluid  to  exude  properly 
by  pressure.  Again,  the  scale  on  which  the  operations  are  to  be 
conducted,  and  considerations  as  to  relative  cost  of  labour,  fuel, 
animal  power  (horses  or  bullocks,  &c.),  value  of  oilcake  when 
expressed  as  far  as  practicable,  or  only  to  a  lesser  extent,  and 
whether  to  be  subsequently  treated  by  solvent  processes  or  not, 
and  so  forth,  have  also  to  be  taken  into  account.  In  general 
terms,  however,  the  plant  may  be  described  as  essentially  con- 
sisting of  boilers  and  engines  for  steam  raising  for  heating  pur- 
poses and  power ;  crushing  machinery  (rolls,  edge  runners,  &c.) 
for  breaking  up  the  material  so  as  to  rupture  the  walls  of  the 
cellular  tissues  in  which  the  oily  matter  is  contained ;  heating 
appliances  whereby  the  material  (either  as  delivered  from  the 
crushers,  or  after  a  preliminary  cold  pressure,  and  subsequent 
disintegration  of  the  partly  expressed  cake)  is  subjected  to  heat 
for  the  twofold  purpose  of  rendering  the  oil  more  fluid,  so  as  to 
facilitate  expression,  and  of  partially  coagulating  albuminous 
matter  so  as  to  obtain  a  purer  product  ;  hydraulic  presses 
whereby  the  expression  is  effected;  and  finally,  filter  presses, 
refining  tanks,  settlers,  and  analogous  appliances,  whereby  the 
crude  oil  is  refined  and  more  or  less  completely  separated  from 
watery  and  organic  matters  accompanying  it  when  first  ex- 
pressed. What  is  now  generally  known  as  the  "  Anglo-American 
system  '"'  substantially  consists  in  the  use  of  a  selection  of  par- 
ticular appliances  for  the  above  purposes  conjoined  with  a  special 
feature — viz.,  that  the  crushed  material,  after  damping  and 
heating  in  a  suitable  "kettle,"  is  subjected  to  a  preliminary 
moulding  operation  so  as  to  shape  and  compress  it  into  compact 
thin  blocks  or  "  cakes,"  which  are  then  expressed. 

The  chief  advantages  of  this  system,  as  employed  in  the  plant 
constructed  by  Messrs.  Rose,  Downs  &  Thompson,  of  Hull,  are 
claimed  to  be  as  follows,  when  contrasted  with  older  systems  of 
arranging  and  working  oil  mill  plant : — • 

All  the  machinery  is  belt-driven ;  whereby  not  only  is  greater 
economy  secured  in  the  cost  of  gearing  and  greater  facility  in 
erection,  but  also  a  considerable  saving  (about  20  per  cent.)  in 
driving  power. 

The  weight  of  the  machinery  requisite  to  work  a  given 
quantity  of  seed  is  materially  reduced,  whilst  the  process  is 
equally  applicable  to  all  oil  seeds  and  nuts,  slight  variations  in 
the  nature  of  the  rolls,  &c.,  being  made  in  some  cases,  according 
to  the  nature  of  the  seed,  &c.,  treated. 

The  plant  is  less  bulky,  a  great  economy  in  space  being 
effected ;  whilst  a  large  saving  (50  per  cent. )  of  labour  in  the 
press  room  is  also  brought  about. 

The  oil  is  more  perfectly  extracted;  thus  linseed  cakes  made 
on  the  old  system  usually  contain  about  10|-  per  cent,  of  oil,  and 


Fig.  46 


OIL    MILL    PLANT.  217 

those  made  by  the  modern  process  only  about  7  per  cent.,  giving 
an  extra  yield  of  oil  to  the  extent  of  about  3J  per  cent,  of  the 
weight  of  the  cake. 

The  bagging  requisite  for  moulded  cakes  is  subjected  to  less 
severe  wear  and  tear  than  that  used  in  the  ordinary  process  ; 
whilst  the  costly  hair  envelopes  are  altogether  abolished.  More- 
over, the  cakes  produced  have  a  better  surface  and  fracture,  and 
are  better  branded  when  the  crushing  is  effected  by  rollers  than 
when  done  by  means  of  edge  stones  in  the  ordinary  way. 

In  what  is  termed  a  "  unit "  mill  on  this  system,  the  plant  is 
capable  of  crushing  from  160  to  200  cwts.  of  linseed  or  rape 
seed  per  day,  or  155  to  190  cwts.  of  cotton  seed.  The  seed 
passes  down  a  shoot  to  a  series  of  crushing  rolls  (usually  five  in 
number),  thence  by  an  elevator  to  the  kettle,  where  it  is  heated; 
a  moulding  machine  forms  it  into  cakes,  which  are  placed  in 
presses  (four  standing  in  one  oil  tank)  and  expressed.  A  paring 
machine  cuts  off  the  oil-containing  edges  of  the  pressed  oilcakes  ; 
these  are  ground  up  under  small  edgestones  and  returned  to 
the  kettle  to  be  worked  over  again  with  a  fresh  batch  of 
crushed  seed.  One  set  of  four  presses  requires  three  men  in  the 
pressroom  and  about  45  actual  horse  power  to  work  it.  For 
larger  mills,  this  "unit"  set  of  plant  is  simply  doubled,  trebled, 
or  quadrupled,  and  so  on,  each  additional  set  requiring  a  further 
addition  of  about  35  actual  horse  power.  In.  very  large 
installations,  where  more  than  two  sets  (eight  presses)  are  used, 
a  system  of  accumulators  is  preferable  rather  than  separate 
pumps  for  each  set  of  four  presses ;  accumulators  at  a  lower 
pressure  being  also  used  for  the  moulding  machines,  cake  hoists, 
ike.,  whereby  a  considerable  saving  is  effected  in  gearing  and 
space.  Fig.  46  exhibits  the  ground  plan  of  a  16-press  installation 
containing  the  following  plant : — 

1  High  pressure  accumulator. 

2  Low  ,, 

16  Hydraulic  presses,  each  with  a  hydraulic  gauge. 

1  Set  of  hydraulic  pumps. 

4  Sets  of  accumulator  stops. 

4      ,,        seedrolls  (5  rolls  in  each). 

4  Seed  kettles. 

4  Moulding  machines. 

2  Paring  ,, 
4  Sets  of  elevators. 

2  Sets  of  edgestones. 
2  Oil  pumps  and  cisterns. 
4  Seed  screens. 

Oil  cisterns  to  hold  200  tons  of  oil. 
Engine  to  work  up  to  200  actual  horse  power. 
Boilers  ,,  250 

together  with  gearing,  elevators,  sack  lift,  pipirg,  &c. 

Such  an  installation  requires  twelve  men  in  the  press  room, 
which  should  measure  66  ft.  by  44  ft.,  the  whole  building  being 


218 


OILS,    FATS,    WAXES,    ETC. 


275  ft.  by  44  ft.,  four  floors.  From  640  to  800  cwts.  of  linseed  or 
rape  seed,  or  from  620  to  760  cwts.  of  cotton  seed  can  then  be 
treated  per  day  of  1 1  hours. 

Crushing  Rolls  and  Edge  Runners.— Fig.  47  represents  a 
set  of  four  superposed  rolls  used  as  above  described ;  these  are 
42  inches  long  and  16  inches  diameter,  and  are  so  arranged  that 
the  seed  is  delivered  from  the  hopper  above  (by  means  of  a  fluted 
feed  roller  the  same  length  as  the  crushing  rolls,  and  a  slanting 
.shoot),  between  the  two  uppermost  rolls ;  having  passed  between 


Fig.  47. 

these,  another  curved  shoot  or  guide  plate  on  the  other  side 
delivers  it  between  the  second  and  third  rolls,  which  crush  it 
further;  in  similar  fashion  it  passes  by  another  guide  plate 
between  the  third  and  fourth  rolls,  where  it  receives  the  final 
grinding.  The  seed  is  thus  crushed  three  successive  times  in  its 
passage  through  the  rolls,  which  are  brought  into  contact  by  a 
combination  of  a  screw  and  india-rubber  springs,  thus  giving  a 
smooth  and  easily  regulated  pressure;  a  much  more  complete 


EDGE    RUNNERS. 


219 


and  perfect  grinding  is  thus  effected  than  is  possible  with  single 
pairs  of  rolls  and  edgestones  of  the  older  construction.  When 
five  rolls  are  employed  in  the  same  train,  the  arrangement  is 
precisely  similar,  four  successive  crushings  being  effected.  For 
small  installations  the  rolls  used  are  similar  in  character,  but  of 
proportionately  smaller  size  ;  thus  a  set  of  four  rolls  (crushing 
the  seeds  thrice  successively),  each  15  inches  long  and  12  inches 


diameter,  suffices  for  a  steam  driven  mill  of  about  half  the 
capacity  of  a  "  unit ;'  and  one  of  three  rolls  (giving  two  suc- 
cessive crushings),  each  8  inches  long  and  8  inches  diameter, 
for  smaller  sizes  still,  driven  by  bullock  power. 

In  some  oil-crushing  establishments  heavy  edge  runners  are 
preferred  to  rolls  for  certain  kinds  of  material — e.g.,  Egyptian 
cotton  seed  and  coprah.  Fig.  48  indicates  a  belt-driven  pair  of 
stones,  8  feet  diameter  and  20  inches  thick  (the  face  being 


220 


OILS,    FATS,    WAXES,    ETC. 


chamfered  to  16  inches);  with  these,  about  6  tons  of  Egyptian 
cotton  seed  may  be  crushed  in  eleven  hours.  The  best  stones 
are  made  of  well  dressed  Derbyshire  gritstone,  free  from  all 
sandholes,  cracks,  shells,  and  other  imperfections,  the  bedstone 
(6  feet  6  inches  diameter  and  22  inches  thick)  being  of  the 
same  material. 

Smaller  sized  stones  suffice  for  grinding  cake  parings ;  for  the 
4-press  "unit"  installation  above  described  one  set  of  stones 
suffices,  4  feet  diameter  and  12  inches  thick  (face  9  inches).  For 
this  purpose,  two  carfe  plates  are  used  instead  of  one,  as  shown 


Fig.  49. 

in  Pig.  48,  the  upper  one  being  perforated,  so  that  the  material 
that  is  being  ground'  may  pass  through  011  to  the  lower  one  as 
soon  as  it  is  sufficiently  pulverised ;  from  the  lower  plate  it  is 
gathered  together  and  discharged  through  a  shuttle  at  any 
convenient  point.  The  texture  of  the  material  thus  ground  is 
regulated  by  the  fineness  or  coarseness  of  the  perforations.  In 


KETTLE    AND    MOULDING    MACHINE. 


221 


some  mills  working  coprah,  slicing  or  rasping  machines  are  em- 
ployed to  cut  up  the  material  before  grinding ;  but  so  much 
damage  is  done  to  the  knives  by  stones  mixed  with  the  coprah 
that  this  previous  treatment  is  now  but  seldom  employed,  special 
disintegrators  being  used  instead  (p.  225). 

Kettle. — The  "  kettle  "  used  in  the  Anglo-American  system 
•consists  of  a  steam-jacketted  circular  castiron  vessel,  furnished 
with  an  agitator  (Fig.  49)  driven  by  a  belt;  a  steam  damping 
apparatus  with  perforated  boss  is  fixed  inside,  so  that  the  crushed 
seed  delivered  into  the  kettle  by  an  elevator  is  moistened  by  the 
condensation  of  steam  from  the  damping  arrangement,  and 
heated  up  uniformly  as  the  mass  is  stirred  by  the  agitator.  By 
means  of  a  slide  at  the  bottom  the  heated  substance  is  delivered 
into  a  box  supplying  the  moulding  machine.  The  kettle  body  is 
fitted  with  a  wooden  frame,  and  covered  over  with  felt  or  slag 
wool  enclosed  within  iron  sheeting  to  keep  in  the  heat.  In  order 
to  save  space,  the  crushing  rolls  are  sometimes  arranged  vertically 
above  the  kettle  ;  but  in  addition  to  the  inconvenience  caused  by 
this  elevation  as  regards  inspection  and  adjustment,  the  steam 
from  the  kettle  is  apt  to  condense  on  the  rolls  and  clog  them  ;  so 
that  this  disposition  is  generally  abandoned  in  the  newer  mills, 
the  crushed  seed  being  delivered  into  the  kettles  by  means  of 
elevators  (Fig.  55)  or  screws,  and  not  by  gravity. 

In  the  older  system  of  working  where  moulding  machines 
are  not  employed,  the  kettles  used  for  heating  the  crushed  seed, 
<kc.,  are  of  similar  character,  but  are  usually  not  supplied  with  a 
damping  arrangement,  as  the  necessity  for  moistening  the 
material  in  order  to  mould  it  better  does  not  then  arise. 

Moulding  Machine. — The  use  of  this  appliance  is  the  most 
distinctive  feature  of  the  Anglo-American  system  ;  the  differences 
between  this  and  the  older 
method  of  procedure  may  be 
thus  stated.  In  the  old  system 
from  11  to  16  Ibs.  of  seed  are 
placed  by  a  boy  in  a  woollen  bag  ; 
the  press  man  takes  up  the  bag, 
doubles  it  back  so  as  to  close  the 
mouth,  and  then  places  it  on  the 
lower  half  of  a  "  hair  "  or  other 
envelope  (Figs.  50  and  5.1  *) 


Fig.  51. 


Fig.  £0. 


*  Envelopes  of  vulcanised  fibre,  paper,  and  other  materials  are  frequently 
employed  instead  of  the  more  expensive  "hairs." 


999 


OILS,    FATS,    WAXES,    ETC. 


that  he  has  previously  placed  on  a  table  in  front  of  the  press. 
He  then  smooths  the  bag  with  his  hand  until  the  seed  is  distri- 
buted throughout  the  interior  as  equally  as  possible.  The  envelope 
is  then  closed  over  the  bag,  and  the  whole  taken  up  and  placed 
in  the  press.  This  process  is  continued  until  the  press  is  filled, 
each  cake,  together  with  its  box,  occupying  a  vertical  thickness 
of  upwards  of  10  inches.  When  the  moulding  machine  is  used, 


Fig.  52. 

each  cake  with  its  plate  only  occupies  3  inches,  thereby  greatly 
increasing  the  capacity  of  the  press  ;  whilst  the  cost  of  labour  is 
considerably  lessened.  The  moulding  is  thus  effected  ;  the  work- 
man begins  by  raising  a  measuring  frame  and  placing  underneath 
it  a  sliding  frame  holding  a  tray  with  a  piece  of  woollen  cloth 
about  double  the  length  of  the  tray  placed  thereon  centre  to 
centre,  the  ends  of  the  cloth  hanging  down ;  the  measuring  frame 


PARING    MACHINE.  223 

is  now  brought  down  on  the  top  of  the  tray  and  cloth,  and 
crushed  seed  introduced  from  a  box  (fed  automatically  from  the 
kettle  as  required)  until  the  frame  is  full.  The  frame  is  then 
thrown  back,  the  loose  ends  of  the  cloth  folded  over  the  seed, 
and  the  sliding  frame  carrying  the  tray,  seed,  and  cloth  pushed 
forward  over  the  pressing  plate.  This  motion  of  the  frame  sets 
the  machine  at  work,  the  pressing  plate  ascending  and  squeezing 
the  seed  into  a  compact  mass  about  li  inch  thick,  after  remain- 
ing in  contact  with  it  about  a  quarter  of  a  minute.  The  pressing 
plate  then  falls,  and  the  machine  stops,  enabling  the  press  man 
to  remove  the  compressed  cake  to  the  press,  carrying  it  011  the 
tray  which  is  withdrawn  as  soon  as  the  cake  is  in  position. 
During  the  time  that  the  cake  is  being  compressed,  the  moulder 
is  engaged  in  forming  another  one  on  a  tray  in  front  of  the 
machine  as  before ;  so  that  cakes  to  the  number  of  240  may  be 
thus  moulded  in  an  hour. 

Fig.  49  represents  a  moulding  machine  actuated  by  steam  in 
position  with  respect  to  the  kettle  ;  other  forms  are  sometimes 
used  worked  by  hydraulic  power. 

Paring  Machine. — The  cakes  obtained  in  the  hydraulic  press 
are  usually  oily  at  the  edges  where  the  oil  exuded,  so  that  the 
edges  require  to  be  cut  off,  not  only  to  trim  the  cakes,  but  also 
to  save  the  oil  with  which  they  are  impregnated,  the  parings 
being  ground  up  and  returned  to  the  kettle.  In  mills  working 
on  the  older  systems  the  press  cakes  are  generally  trimmed  by 
hand ;  but  the  simple  form  of  machine  indicated  in  Fig.  52  not 
only  enables  the  parers  to  do  much  more  work  in  a  given  time,, 
but  also  to  cut  the  edges  far  more  regularly  and  neatly.  The 
cake  to  be  pared  is  placed  with  one  edge  over  a  central  longi- 
tudinal trough  ;  a  cutter  block  with  attached  knife  passes  along^ 
and  shears  off  the  portion  of  the  cake  projecting  beyond  a  given 
line,  being  driven  by  the  excentric  working  a  bar  jointed  to  the 
upper  part  of  the  frame.  The  other  side  and  ends  of  the  cake 
are  trimmed  in  the  same  way,  two  knives  being  attached  to  the 
cutter  block,  one  cutting  when  the  motion  is  in  one  direction,, 
the  other  when  in  the  opposite  direction.  A  screw  works  in  the 
trough,  so  that  as  the  parings  fall  they  are  carried  onward  by  the- 
screw  and  delivered  on  to  the  upper  carfe  plate  of  a  pair  of  edge- 
stones  (Fig.  48),  whereby  they  are  reduced  to  meal,  which  is  then 
taken  up  and  distributed  to  the  kettles  by  elevators  and  screws. 

Supplementary  Appliances. — In.  addition  to  the  preceding- 
principal  appliances,  various  other  minor  arrangements  are  re- 
quisite in  a  well  appointed  oil  mill.  Thus,  screens  of  various 
sizes  of  mesh  are  necessary  in  order  to  sift  out  stones,  &c.,  and 
to  partially  separate  different  kinds  of  admixed  seeds  when  their 
respective  dimensions  renders  this  practicable.  Machines  for 
decorticating  seeds  are  also  employed.  Fig.  53  represents  cotton 
seed  treated  by  such  a  machine.  A,  ordinary  Egyptian  seed 


224 


OILS,    PATS,    WAXES,    ETC. 


coated  with  "cotton  filaments ;    the  machine   cuts   through  the 
husk  and  kernel,  B ;  a  separator  then  divides  the  husks,  C,  from 


Fig.  53. 

the  oily  kernels,  D,  the  latter  being  crushed  and  expressed,  and 
the  former  used  for  manure,  Arc.  Similarly,  castor  beans  are 
contained  in  an  outer  shell  (Fig.  54,  A) ;  a  special  castor  seed 


decorticating  machine  removes  the  outer  shell,  B,  leaving  the 
white  kernel,  C,  ready  for  the  press.  Analogous  machines  are 
employed  for  decorticating  arachis  nuts  and  for  splitting  coker- 
nuts,  cutting  through  husk,  shell,  and  kernel  at  one  opera- 
tion ;  and  for  grinding  and  disintegrating  coprah.  Pulverising 
machines  for  this  purpose,  where  the  action  is  brought  about  by 
a  series  of  blows  from  rapidly  moving  flat  beaters,  answer  better 
than  those  where  the  grinding  is  effected  between  parallel  iron 


CHEMICAL    DECORTICATION. 


225 


discs  by  friction.  Fig.  55  illustrates  the  arrangement  used  when 
such  a  disintegrator  is  mounted  directly  over  the  kettle,  and  fed 
by  an  elevator. 

Dudley  <fe  Perry  have  patented  a  process*  for  chemically 
decorticating  cotton  seed.  The  seeds,  after  linting,  are  subjected 
to  the  action  of  gases  containing  nitrous  anhydride  and  sulphur 
dioxide,  with  enough  air  to  "  regenerate "  the  higher  oxides  of 
nitrogen  as  fast  as  they  are  reduced.  After  a  few  seconds 


Fig.  55. 

exposure  the  fibre  has  changed  but  little  in  appearance,  but  its 
structure  is  completely  destroyed,  so  that  the  slightest  friction 
causes  it  to  fall  to  an  impalpable  powder,  leaving  the  seeds 
perfectly  smooth,  and  showing  no  signs  of  corrosion.  A  slight 
acid  reaction  is  perceptible  on  the  outside,  easily  removable  by 
washing ;  but  no  acid  penetrates  into  the  interior. 


*U.  S.  Patent  344, 951. 


15 


226 


OILS,    FATS,    WAXES,    ETC. 


The  crude  expressed  oil  carries  with  it  more  or  less  watery 
matter,  together  with  mucilaginous  and  albuminous  organic  sub- 


Fig.  56. 


. 


Fig.  57. 


Fig.  58. 


FILTER    PRESS. 


227 


228  OILS,    FATS,    WAXES,    ETC. 

stances,  requiring  processes  to  be  adopted  for  their  removal. 
Formerly  these  generally  involved  long  continued  standing,  so  as 
to  enable  the  solid  impurities  to  form  and  settle,  the  process  being 
in  some  cases  hastened  by  heating  to  coagulate  albuminous  matter, 
or  by  the  use  of  chemicals  (vide  Chap,  xi.)  In  many  cases,  how- 
ever, it  is  found  that  a  degree  of  clarification  sufficient  to  render 
the  oils  immediately  saleable,  can  be  rapidly  effected  by  simply 
pumping  the  oil  (either  just  as  it  runs  from  the  press  into  the  oil 
well,  or  after  heating  to  a  temperature  somewhat  short  of  100°  C. 
to  coagulate  mucilage,  &c.)  through  a  filter  press  ;  the  matters 
thus  filtered  out  from  the  oil  are  generally  returned  to  the  kettle- 


Fig.  60. 

and  worked  over  again  with  a  fresh  batch  of  crushed  seed,  so 
that  the  only  products  finally  obtained  are  filtered  oil  and 
pressed  cake,  no  "foots"  of  any  kind  being  made.  In  the  case 
of  many  kinds  of  oil  this  simple  treatment  suffices  to  refine  the 
oil  sufficiently  for  most  purposes  ;  in  other  cases,  although  subse- 
quent refining  methods  are  still  requisite,  yet  on  account  of  the 
previous  removal  by  filtration  of  a  large  proportion  of  the 
impurities,  the  rest  of  the  refining  process  is  much  facilitated 
and  shortened.  Accordingly,  in  the  newest  installations  suit- 
able filter  presses  form  an  important  part  of  the  subsidiary 
appliances  employed. 

Fig.  56  represents  a  hydraulic  filter  press  with  self-contained 


SEPARATION    OF    STEARINES.  229 

engine  and  pump,  made  by  Messrs.  S.  IT.  Johnson  £  Co.,  of 
Stratford ;  the  plates  are  "  recessed,"  so  that  the  raised  rims  of 
the  consecutive  plates  enclose  a  space  when  they  come  together, 
which  finally  becomes  filled  with  the  solid  matters  taken  from 
the  material  filtered.  Figs.  57  and  58  represent  the  front  eleva- 
tion and  sectional  elevation  of  the  plates,  which  are  provided 
with  adjustable  tension  hooks  to  carry  the  cloths,  and  stay  boss 
projections  so  as  to  prevent  fracture  of  the  plates  when  work- 
ing under  high  pressure,  each  plate  supporting  the  next  adjoin- 
ing one  from  end  to  end  of  the  machine.  Figs.  59  and  60 


Fig.  61. 

represent  a  different  type  of  plate  surface  ("  Pyramid  drainage  " 
surface),  whereby  washing  of  the  cakes  produced  is  more  readily 
effected,  and  the  efficiency  of  the  press  largely  increased  in  the 
case  of  viscid  liquids.  Fig.  61  represents  a  miniature  pattern 
of  hand-worked  press  for  small  operations  and  experimental 
purposes. 


SEPARATION  OF  SOLID  STEARINES  FROM  OILS,  &c. 

Many  oils  when  allowed  to  stand  for  some  time  at  a  sufficiently 
low  temperature  deposit  more  or  less  copious  amounts  of  solid 
matter,  sometimes  becoming  semisolid  or  buttery  in  so  doing. 
If  the  temperature  be  raised  the  whole  mass  melts  again  to  a 
fluid  oil ;  but  by  "  bagging  "  (or  straining  off  the  liquid  portion 
through  canvas  bags  forming  rough  filter-strainers)  without  apply- 
ing heat,  the  solid  matter  may  be  collected ;  and  by  applying 
pressure  to  the  "  bagged "  mass  the  remaining  liquid  may  be 
squeezed  out.  When  the  solid  matter  thus  collected  is  sufficiently 
granular,  the  ordinary  method  of  cold  pressing  may  be  conve- 
niently applied,  the  process  being  carried  out  in  much  the  same 


230  OILS,    FATS,    WAXES,    ETC. 

way  as  that  above  described  in  the  case  of  crushed  seed  pulp, 
excepting  that  the  pressure  is  applied  more  gradually  and  gently ; 
but  in  many  cases  the  solid  particles  are  so  fine  that  they  are 
largely  forced  through  the  interstices  of  the  press  cloth  (even 
when  specially  made  cloths  are  employed)  and  thus  lost  in  the 
liquid  runnings.  In  cases  where  the  solid  matter  is  present  in 
too  small  quantity  for  ordinary  cold  pressing  filter  presses  may 
often  be  conveniently  employed  to  collect  and  consolidate  the 
solidified  constituents.  Thus  olive  oil  when  cooled  for  some  time 
deposits  a  considerable  fraction  of  the  more  solid  glycerides  con- 
tained (palmitin,  stearin,  arachin) ;  these  when  collected  by  the 
filter  press  furnish  an  "olive  stearine,"  whilst  the  filtered  oil  is 
proportionately  less  liable  to  thicken  and  deposit  in  cold  weather. 
Similarly  cotton  seed  oil  furnishes  a  considerable  amount  of 
"  cotton  stearine  "  and  a  more  fluid  liquid  oil,  known  in  conse- 
quence as  winter  oil.  Animal  oils,  such  as  cod  liver  oil  and  whale 
oil,  furnish  analogous  stearines ;  from  sperm  oil,  spermaceti  is 
similarly  separated. 

In  the  manufacture  of  paraffin  wax  for  candle  making,  &c., 
certain  fractions  of  the  distillates  obtained  consist  of  mixtures  of 
hydrocarbons  of  different  melting  points,  some  fusing  at  con- 
siderably above  the  ordinary  temperature.  On  chilling  such 
"  oils,"  by  means  of  a  suitable  frigorific  machine,  the  hydro- 
carbons of  higher  fusing  point  mostly  separate  in  the  solid 
form ;  so  that  by  straining  the  magma,  or  subjecting  it  to  filter 
pressure,  the  solid  paraffins  are  separated  from  those  yet  liquid. 
The  solid  matters  thus  obtained  (paraffin  scale),  when  refined, 
redistilled,  and  subjected  to  further  pressings  at  regulated  tem- 
peratures, ultimately  furnish  "  paraffin  wax "  of  melting  point 
the  more  elevated  the  higher  the  temperature  at  which  the  last 
warm  pressing  has  been  effected,  this  temperature  being  regu- 
lated by  the  nature  of  the  material  dealt  with,  some  kinds  of 
distillates  furnishing  paraffin  wax  of  higher  melting  point  than 
can  be  isolated  from  others. 

Similar  operations  are  gone  through  in  various  other  manufac- 
tures connected  with  the  coaltar  and  mineral  oil  industry ;  thus 
the  separation  of  carbolic  acid  from  mixtures  of  that  substance 
and  its  homologues  and  other  bodies  accompanying  it,  is  effected 
by  chilling  by  means  of  an  ether  or  ammonia  freezing  machine, 
and  draining  off  the  unfrozen  liquid  from  the  mass  of  crystals 
that  gradually  forms.  Similarly  "  anthracene  oils,"  obtained  at 
a  certain  stage  of  coaltar  distillation,  become  more  or  less  pasty 
and  semisolid  on  cooling  and  standing ;  so  that  by  straining 
off  the  liquid  portions  (by  filter  pressing  or  otherwise)  and  sub- 
sequently expressing  the  remaining  liquid  by  more  powerful 
pressure,  a  solid  residue  is  ultimately  obtained,  consisting  of 
anthracene  intermixed  with  other  solid  hydrocarbons,  &c. 

In    the    manufacture  of   "stearine"    for    candles  (stearic  and 


EXTRACTION    OF   OIL    BY    SOLVENTS.  231 

palmitic  acids,  &c.,  p.  110),  similar  operations  are  gone  through 
for  the  purpose  of  isolating  mechanically  the  solid  fatty  acids 
that  have  crystallised  into  a  honeycombed  mass,  the  interstices 
of  which  are  filled  with  the  liquid  acids  ("  red  oils.").  Hydraulic 
pressure  of  the  spongy  solid  mass  in  sacking  serves  to  effect  a 
first  separation  of  matters  respectively  solid  and  liquid  at  the 
ordinary  temperature.  Further  "  hot  pressing "  at  a  more 
elevated  temperature  brings  about  a  more  complete  elimina- 
tion of  liquid  acids  from  the  crude  once-pressed  stearine ;  whilst 
by  chilling  the  red  oils,  a  separation  of  part  of  the  solid  acids 
dissolved  in  them  takes  place,  so  that  by  filter  pressing  the 
mass  fluid  red  oils  run  through,  whilst  an  additional  quantity  of 
impure  solid  acids  is  retained  on  the  filter  cloths. 

Manufacture  of  Lard  Oil,  and  Allied  Products. — At  the 
ordinary  temperature  of  15°  to  25°  C.,  lard  constitutes  a  soft 
mass  consisting  of  two  kinds  of  matter,  one  solid  and  one  fluid; 
it  is,  in  fact,  an  exaggerated  case  of  the  mechanical  separation 
from  one  another  of  two  constituents  of  a  mixture  possessing 
different  solidifying  points  when  the  temperature  is  maintained 
between  the  two  temperatures  of  fusion,  chiefly  differing  from 
the  partial  solidification  of  fluid  oils  on  cooling  and  standing 
in  that  the  solid  constituent  has  a  higher  melting  point,  and  is 
present  in  larger  quantity.  By  placing  the  lard  in  close  textured 
woollen  bags  supported  by  wickerwork  frames,  and  subjecting 
it  to  long  continued  cold  pressure  (about  10  cwts.  per  square 
inch,  lasting  for  some  18  hours),  the  fluid  constituent  is  grad- 
ually expressed  and  the  solid  retained.  The  former  is  known  as 
"lard  oil,"  and  constitutes  about  three-fifths  of  the  whole;  the 
latter  is  "lard  stearine,"  and  is  a  valuable  material  for  the  pre- 
paration of  the  better  kinds  of  soaps. 

Coker  butter  (cokernut  oil  kept  at  not  too  high  a  temperature) 
and  other  analogous  vegetable  semisplid  oils  or  butters,  can,  in 
like  manner,  be  separated  by  pressure  into  a  fluid  "  coker  oleine," 
and  a  solid  "  coker  stearine ;  "  and  in  similar  fashion,  the  more 
fusible  fats  obtained  in  the  first  process  for  the  manufacture  of 
butterine,  solidify  at  a  suitable  temperature  to  a  semisolid  mass, 
which,  when  carefully  pressed,  yields  a  fluid  portion  becoming 
of  a  buttery  consistence  when  cooled  a  little  further,  and  a  solid 
stearine  suitable  for  candle  and  soap  making.  Fats  of  greater 
.solidity  at  ordinary  temperatures,  such  as  tallow,  when  similarly 
expressed,  also  separate  into  two  portions — e.g.,  liquid  "  tallow 
oil  "  and  solid  "  tallow  stearine." 

EXTRACTION  OF  OIL  FROM  SEEDS,  OIL  CAKE,  &c., 
BY  SOLVENTS. 

Most  oily  matters  are  extremely  freely  soluble  in  benzene, 
light  petroleum  distillate,  ether,  chloroform,  carbon  disulphide, 


232  OILS,    FATS,   WAXES,    ETC. 

and  other  readily  volatile  solvents ;  so  that  by  bringing  such 
fluids  in  contact  with  the  material  to  be  treated,  the  oleaginous 
matter  is  dissolved,  whilst  the  other  constituents  are  mainly 
unaffected.  By  drawing  off  the  solution  and  subjecting  it  to 
distillation  the  solvent  is  volatilised,  and  with  proper  condens- 
ing arrangements  can  be  regained  with  but  little  loss  for  use 
over  again,  whilst  the  oil  remains  in  the  still. 

A  large  number  of  different  arrangements  have  been  proposed, 
and  many  are  in  actual  use  (more  especially  on  the  Continent) 
for  effecting  this  purpose,  differing  in  various  respects  according 
to  the  nature  of  the  material  to  be  treated  and  the  solvent 
employed,  £c.  When  the  material  is  rich  in  oil — e.g.,  when 
palm  kernels  (ground  to  meal)  are  used,  and  similar  substances 
not  already  largely  deprived  of  oil  by  expression,  the  apparatus 
employed  essentially  consists  of  a  cylinder  or  other  closed  tank 
of  boiler  plate,  provided  with  a  manhole  for  charging  and  dis- 
charging the  meal,  which  is  supported  on  a  perforated  false 
bottom.  Into  this  carbon  disulphide  is  run  by  gravitation,  or 
pumped  from  a  well,  entering  at  the  bottom  and  passing  upwards 
through  the  mass  (or  vice  versa  when  light  petroleum  spirit  is 
used)  •  the  fluid  dissolves  out  the  oil,  and  runs  away  at  the  exit 
either  direct  to  the  distilling  apparatus,  or  to  another  similar 
cylinder  where  it  dissolves  out  more  oil,  furnishing  a  stronger 
solution.  With  substances  less  rich  in  oil,  such  as  oilcakes, 
several  cylinders  are  usually  worked  in  succession,  the  fluid 
percolating  through  each,  and  ultimately  yielding  a  largely  con- 
centrated fatty  solution,  much  as  in  the  methodical  lixiviation 
apparatus  employed  in  dissolving  crude  sodium  carbonate  from 
black  ash  in  the  Leblanc  soda  process.  The  supply  of  disulphide 
to  the  first  cylinder  is  kept  up  until  a  sample  of  the  issuing  fluid 
is  found  to  contain  little  or  no  oil  in  solution.  The  connection 
with  the  disulphide  supply  is  cut  off,  and  then  by  means  of  a 
current  of  compressed  air  or  of  steam,  the  fluid  in  the  first 
cylinder  is  forced  onwards  into  the  second,  which  is  then 
coupled  to  the  supply,  becoming  the  first  of  the  series.  The 
disulphide  still  adherent  to  the  exhausted  material  in  the  first 
cylinder  is  volatilised  by  means  of  steam,  let  in  under  the  false 
bottom  (or  at  the  top),  the  vapours  being  carried  to  a  condensing 
worm,  where  a  mixture  of  water  and  disulphide  is  condensed. 
The  exhausted  material  is  then  discharged,  the  cylinder  refilled, 
and  coupled  to  the  series  at  the  far  end,  so  that  the  disulphide 
passing  in  has  already  a  considerable  amount  of  oil  in  solution. 
In  this  way  the  nearly  exhausted  material  is  fed  with  fresh 
disulphide,  whilst  the  newly  refilled  cylinder  is  supplied  with 
comparatively  strong  solution ;  the  liquid  ultimately  passing  out 
is  led  away  to  a  distilling  apparatus,  where  the  volatile  disulphide 
is  steamed  off,  and  the  residual  fat  finally  collected. 

Fig.    62   (Schadler)  illustrates  a  set   of  four  steam-jacketted 


EXTRACTION    OF    OIL    BY    SOLVENTS. 


233 


cylinders  thus  used  in  series.  A1?  A2,  A3,  A4,  are  the  four  vessels 
so  connected  by  pipes  D1?  D2,  D3,  D4,  that  the  liquid  passing  off 
at  the  top  of  each  is  supplied  to  the  bottom  of  the  next,  Al  being 
reckoned  as  next  to  A4.  These  connections  are  opened  and 
closed  as  required  by  means  of  the  cocks  EI}  E0,  E3,  E4 ;  H15  H2, 
H3,  H4  are  pieces  of  glass  tubing  serving  as  gauges.  B  is  the 
carbon  disulphide  supply  pipe  ;  by  means  of  the  two-way  cocks, 
Cj,  C2,  C3,  C4,  fresh  disulphide  can  be  supplied  to  any  one  of  the 
four  vessels  as  required.  N  is  a  steam  pipe  from  which  steam  is 
blown  in  to  any  vessel  by  means  of  the  cocks  O15  O2,  O3,  O4,  or 
into  the  jackets  through  the  cocks  Pj,  P2,  P3,  P4.  F  is  the 
saturated  carbon  disulphide  main,  the  final  solution  flowing  into 
it  through  the  cocks  Q-v  G2,  G3,  G4.  J  is  a  pipe  into  which  the 
liquid  contents  of  the  cylinders  can  be  blown  off  through  the 
cocks  K1?  K2,  K3,  K4.  L  is  a  compressed  air  main  from  which 
air  can  be  supplied  to  each  cylinder  by  the  cocks  J\J  v  M2,  M3,  M4. 


Fig.  02. 

Suppose  all  four  vessels  filled  with  material  to  be  exhausted; 
by  opening  the  cock  C15  connection  is  established  between  the 
disulphide  main,  B,  and  the  cylinder  A2,  through  the  pipe  D,, 
and  cock  E2 ;  disulphide  then  flows  into  A0,  percolating  through 
the  material  until  the  level  of  the  cock  C2  is  reached ;  this  is 
set  so  as  to  shut  off  the  disulphide  main  and  open  the  connection 
with  A3  through  D2  and  E0,  consequently  the  disulphide  passes 
onwards  into  Ar  In  similar  fashion  it  passes  successively  into 
A4  through  C3,  D3,  and  E4,  and  into  Al  through  C4,  D4,  and  Er 
Finally,  it  is  drawn  off  through  Gl  into  the  saturated  solution 
main,  F,  whence  it  flows  to  the  still  (or  an  intermediate  store 
tank).  The  progress  of  the  extraction  is  judged  by  the  colour 
visible  at  the  gauge,  H2 ;  when  the  liquor  is  seen  to  be  devoid  of 
colour,  all  available  oil  has  been  dissolved.  The  cock  Cj  is 
then  closed  so  as  to  shut  off  the  disulphide  supply,  E2  is  closed, 


234 


OILS,    FATS,    WAXES,    ETC. 


and  M2  and  K2  opened,  so  that  compressed  air  enters  A9  and 
forces  the  liquid  contents  out  through  the  discharge  pipe,  j";  the 
steam  cocks  O2,  P2  are  then  opened,  so  that  the  cylinder  and 
contents  are  heated,  the  disulphide  vapour  thus  produced  being 
driven  out  along  with  some  water  vapour  through  J  to  a  con- 
densing apparatus.  To  avoid  loss  of  disulphide  vapours  not 
completely  condensed  but  carried  away  with  the  escaping  air, 
this  is  made  to  pass  through  an  absorbing  vessel  containing  oil 
which  dissolves  out  the  disulphide,  forming  a  liquid  from  which 
the  disulphide  is  recovered  by  distillation  when  strong  enough. 

The  cylinder  A2  being  exhausted  and  all  disulphide  steamed  off, 
the  manhole  is  opened,  the  exhausted  charge  withdrawn,  and 
a  new  one  introduced.  A2  is  then  coupled  on  in  front  of  A1  and 
the  whole  operation  recommenced,  the  order  in  which  the  fresh 
disulphide  passes  through  the  series  being  now  A3,  A4,  A1?  A0, 

J  J 


1C 


Fig.  63. 

instead  of  A9,  A3,  A4,  Ap  as  at  first.     In  similar  fashion,  A3,  A4, 
and  A!  are  in  turn  exhausted  and  recharged. 

Fig.  63  represents  a  Heyl's  distillation  apparatus  for  boiling 
off  the  carbon  disulphide  from  the  fatty  solution  thus  obtained. 
A  is  a  boiler-plate  vessel  furnished  with  a  steam  jacket,  B,  at 
the  base.  Steam  is  let  in  at  C,  and  the  condensed  water  drawn 
off  at  D.  The  disulphide  solution  is  supplied  at  E,  the  gauge  F 
enabling  the  right  level  to  be  attained.  L  is  the  draw-off  pipe 


EXTRACTION    OF   OIL    BY    SOLVENTS. 


235 


for  the  oil  finally  left ;  J  J  exit  leading  to  condenser ;  H  an 
agitator  worked  by  a  handle,  G ;  K,  a  tube  through  which 
steam  can  be  led  in  to  a  circular  pipe  at  the  base  inside,  per- 
forated with  a  number  of  minute  orifices.  The  solution  being 
run  in,  steam  is  turned  on  when  boiling  soon  commences,  the 
disulphide  vapours  being  led  away  through  J  to  the  condenser. 
The  agitator,  H,  facilitates  the  evaporation ;  at  the  end  steam 
is  blown  in  through  K,  so  as  to  pass  through  the  residual'  oil  in 
a  multitude  of  fine  streams,  and  so  drive  off  the  last  traces  of 
disulphide  vapour.  Finally,  the  oil  is  drawn  off  through  L,  and 
a  fresh  charge  introduced. 

Fig.  64  represents  a  simpler  form  of  extraction  apparatus 
(Deitz's),  consisting  of  an  extraction  tank,  B,  into  which  disul- 
phide is  pumped  at  the  bottom  from  the  well,  A,  by  the  pipe,  h, 
the  fatty  solution  passing  off  at  the  top  through  the  pipe,j^  to 
the  still,  D  ;  the  vapours  here  evolved  are  led  away  through 
the  pipe,  ee,  and  condensed  by  the  worm,  C,  the  condensed 
disulphide  returning  to  the  well,  A.  When  the  extraction  is 
complete,  the  disulphide  supply  is  shut  off  and  steam  injected 
into  B  through  a  coil  at  the  base  below  the  false  bottom,  d  d ; 


Fig.  64. 

the  residual  fluid  in  B  is  thus  forced  back  into  A,  and  as  the 
heat  becomes  greater,  the  disulphide  still  remaining  in  the  ex- 
hausted mass  is  volatilised  and  carried  to  the  worm,  C,  through 
the  pipe,  e  e.  The  heat  is  supplied  to  the  still,  D,  by  means  of  a 
steam  coil  inside ;  finally,  steam  is  blown  through  the  residual 
oil  to  remove  the  last  traces  of  disulphide,  and  the  oil  drawn  off 
through  the  discharge  pipe,  i.  A  series  of  these  extractors  is 
generally  employed,  worked  in  couples  alternately. 

Carbon  disulphide  being  heavier  than  water  is  comparatively 
readily  protected  from  evaporation  by  a  layer  of  that  fluid  on 
its  surface ;  on  the  other  hand,  its  vapour  is  very  -  readily 


236  OILS,    FATS,    WAXES,    ETC. 

inflammable,  and  when  breathed  for  long  periods  produces  a 
peculiar  form  of  poisonous  action,  culminating  in  a  species  of 
insanity.  Light  petroleum  spirit  is  cheaper,  but,  owing  to  its 
being  lighter  than  water,  cannot  be  so  well  protected  from 
evaporation  and  consequent  danger  of  fire  and  of  explosion  when 
a  mixture  of  its  vapour  and  air  is  ignited  ;  moreover,  its  solvent 
action  is  less  rapid.  The  former  solvent  is  more  generally  used 
in  Europe,  the  latter  in  America.  Grills  &  Schrceder  have 
patented  the  use  of  liquefied  sulphur  dioxide  at  30°  to  40°  C. 
under  a  pressure  of  some  six  atmospheres  as  a  solvent  for  oils 
for  extraction  purposes  (Patent  No.  19,948,  Dec.  11,  1889) ;  and 
Lever  &  Scott  have  similarly  patented  the  use  of  carbon  tetra- 
chloride,  which  is  said  to  yield  a  purer  product  than  carbon 
disulphide  (Patent  No.  18,988,  Nov.  26,  1889). 

Extraction  of  Grease  from  Engine  Waste,  &c. — The 
greasy  cotton  waste,  rags,  &c.,  that  accumulate  where  machinery 
is  largely  used  from  the  wiping  of  spindles  and  cleansing  of  metal 
work,  &c.,  and  similar  materials  are  sometimes  treated  with 
solvents  for  the  •  purpose  of  recovering  the  oily  matter,  after 
which  the  material  is  more  or  less  cleansed  by  boiling  with 
alkalies,  &c.,  and  washing,  so  as  either  to  be  capable  of  use  over 
again  or  to  be  suitable  for  paper  making.  The  plant  used  for  this 
purpose  differs  little  from  that  above  described.  An  old  boiler 
or  some  similar  vessel  is  erected,  a  false  bottom,  or  grating  sup- 
plied at  the  base,  and  suitable  manholes.  The  solvent  liquid  is 
run  in  (from  the  base,  if  carbon  disulphide,  because  that  liquid 
becomes  lighter  by  dissolving  fatty  matters ;  from  the  top,  if 
light  petroleum  spirit,  for  the  opposite  reason),  so  as  to  percolate 
through  the  greasy  rags,  tfcc.,  the  solution  obtained  being  distilled 
so  as  to  recover  the  solvent  and  separate  the  grease.  Owing  to 
the  prevalent  use  of  hydrocarbons  in  preparing  lubricating  oils, 
the  grease  thus  obtained  is  rarely  available  for  soap  making, 
except  when  largely  admixed  with  other  fatty  materials. 

Fig.  65  represents  an  arrangement  used  in  Lancashire  for  the 
purpose  of  cleansing  engine  waste,  and  recovering  grease  there- 
from. It  consists  of  a  vessel  of  boiler  plate,  about  9  feet  high 
and  6  diameter,  with  a  grating,  F,  forming  a  false  bottom,  and  a 
gooseneck  leading  to  a  worm  condenser,  C ;  G  is  a  pipe  supplying 
steam,  and  E  a  cock  for  withdrawing  grease.  The  grating,  F,  is 
fixed  about  2  feet  above  the  bottom,  and  consists  of  a  disc  of 
i-inch  boiler  plate  pierced  with  numerous  slightly  conical  holes, 
1J  inch  diameter  on  the  upper  side,  1  inch  diameter  on  the 
under  side.  Some  3  tons  of  greasy  waste  are  shovelled  in 
through  the  upper  manhole,  A.  Coaltar  benzene,  boiling  not 
higher  than  100°  C.,  or  benzoline  (light  petroleum  distillate) 
is  then  pumped  in  through  A,  and  percolating  through  the  mass 
dissolves  out  grease,  accumulating  under  the  false  bottom.  A  is 
then  closed  and  made  vapour  tight  with  lime  paste. 


EXTRACTION  OF  GREASE  FROM  ENGINE  WASTE. 


237 


Steam  is  then  blown  in  through  the  pipe,  G ;  the  vapours 
evolved  at  first  become  condensed  in  the  comparatively  cool  mass 
of  waste  above,  and  thus  serve  to  wash  out  the  remaining  greasy 
solution  adhering  thereto ;  by  and  bye  the  vapours  pass  over  into 
the  condensing  worm,  C,  made  of  2  to  3-inch  leaden  or  iron 
piping,  arranged  so  as  to  form  10  to  12  turns  6  feet  in  diameter; 
a  plentiful  supply  of  cold  water  is  admitted  at  the  base  of  the 
cistern  in  which  the  worm  is  set,  passing  off  by  an  overflow  pipe 
at  the  top.  Finally,  when  all  volatile  matters  are  expelled  from 
the  still,  and  nothing  but  water  is  condensed  in  the  worm,  the 
steam  is  shut  off,  and  the  waste  extracted  through  the  lower 
manhole,  B.  To  complete  the  cleansing  it  is  boiled  in  a  kier 
with  soda,  washed  plentifully  with  water  in  a  dash- wheel,  soaked 
in  dilute  hydrochloric  acid  to  dissolve  out  oxide  of  iron,  again 


Fig.  65. 

washed  in  the  dash- wheel,  drained  in  a  centrifugal  machine,  and 
hung  up  to  dry.  From  50  to  60  per  cent,  of  cleansed  waste  is 
usually  thus  obtained  from  the  greasy  raw  material. 

The  recovered  benzene  runs  along  with  the  condensed  water 
through  D  to  a  covered  cistern  (conveniently  an  old  boiler), 
where  the  two  separate  by  gravitation ;  the  lighter  hydrocarbon 
is  pumped  up  again  into  the  extraction  vessel  for  a  new  charge, 
whilst  the  water  is  run  away  from  time  to  time  as  it  accumulates, 
by  means  of  a  cock  at  the  bottom  of  the  cistern.  The  grease  thus 
recovered  is  generally  too  impure  to  be  used  directly  for  anything 
but  cart  grease  or  other  coarse  lubricating  purposes.  By  distil- 
lation with  superheated  steam,  it  may  be  partially  purified 
and  rendered  serviceable  for  various  other  purposes. 

Somewhat  similar  methods  are  in  use  for  the  extraction  of 
"  woolfat "  from  raw  wool  (vide  Chap,  xv.,  lanolin). 

Determination  of  Fat  in  Seeds,  &c. — When  it  is  required 
to  determine  analytically  the  amount  of  oleaginous  matter 


238 


OILS,    FATS,    WAXES,    ETC. 


present  in  a  solid  substance  chiefly  containing  non-fatty  con- 
stituents (e.y.t  crushed  seeds  or  oilcake,  the  residue  left  on 
evaporating  milk  or  cream,  and  such  like  materials),  the  process 
adopted  is  substantially  an  application  on  the  small  scale  of  the 
general  principles  involved  in  the  large-scale  extraction  methods- 
above  described.  When  the  fatty  matter  predominates,  the 
weighed  portion  of  substance  is  stirred  up  with  ether,  chloroform , 
light  petroleum  spirit,  carbon  disulphide,  or  other  convenient 
solvent,  and  the  whole  poured  into  a  weighed  paper  filter,  the 
undissolved  matters  being  thoroughly  washed  out,  and  examined 
as  found  requisite  after  drying  and  weighing  (p.  123).  When, 
however,  the  fatty  constituents  are  in  the  minority,  the  process 
is  slightly  modified :  the  coarsely  powdered  material  is  placed 
inside  a  piece  of  glass  tubing,  the  lower  part  of  which  is 
constricted  and  blocked  with  cotton  wool,  glass  wool,  or  asbestos 
fibres,  &c.,  so  as  to  form  a  strainer;  the  solvent  is  poured  into 
the  tube,  percolates  slowly  through  the  pulverised  material,  and 
passes  out  at  the  lower  end  (filtered  clear. by  the  cotton  WTOO!) 
into  a  vessel  placed  to  receive  it,  the  dissolved  fatty  matters 
being  obtained  in  weighable  form  by  evaporating  off  the  solvent. 
Solution  of  fatty  matter  takes  place  more  rapidly  under  such 
circumstances  if  the  solvent  be  warm;  to  effect  this,  as  well  as 
to  economise  labour  and  solvent,  various  devices  are  in  use, 

essentially  modifications  of  the 
arrangement  described  bySoxhlet, 
and  generally  known  as  "Soxhlet's 
tube."  Fig.  66  represents  one  of 
the  earliest  forms,  and  Fig.  67  an 
improved  form,  less  fragile.  The 
substance  to  be  exhausted  is  placed 
.in  the  wider  tube,  A  (Fig.  66),  the 
lower  part  of  which  is  stopped 
with  a  loose  plug  of  cotton  wool, 
&c.,  or  it  is  wrapped  in  filter  paper 
so  as  to  form  a  cylindrical  package, 
fitting  loosely  into  A.  No  con- 
nection subsists  between  the  inte- 
rior of  B  and  A  except  through 
the  side  pipe,  C.  The  lower  end 
of  B  is  made  to  pass  through  a 
perforated  cork  into  a  weighed 
flask  ;  the  upper  end  of  A  is 
similarly  connected  with  a  reflux 
condenser,  preferably  of  Allihns 
form,  Fig.  68.  A  suitable  quan- 
tity of  solvent  being  placed  in  the  flask,  on  heating  this  (by 
a  waterbath,  <fcc.)  the  liquid  is  vapourised,  and  passes  upwards 
through  B  and  C  to  the  condenser;  the  condensed  fluid  drops 


Fig.  66. 


Fig.  67. 


LABORATORY   FAT    EXTRACTION    PROCESSES. 


239 


down  into  A  on  to  the  substance  to  be  exhausted ;  when  the 
fatty  solution  accumulates  to  the  level,  h,  the  siphon,  D  D  D, 
begins  to  act,  and  draws  off  the  fluid  into  the  flask.  After  some 
20  or  30  siphonings,  all  trace  of  fatty  matter  is  dissolved  out; 
by  disconnecting  the  flask,  and  evaporating  off  the  remaining 


Fig.  68. 

solvent,  the  dissolved  oil  is  obtained.  In  this  way  the  solution 
is  effected  by  means  of  solvent  appreciably  warmed  by  contact 
with  the  hot  vapour  in  the  upper  part  of  A,  whilst  the  operation 
goes  on  automatically.  v 

Figs.  69  and  70  represent  an  improved  form  of 
Soxhlet  tube,  arranged  by  B.  Friihling  •*  the  sub- 
stance to  be  examined  is  placed  in  the  vessel  A, 
Fig.  69,  provided  with  an  internal  siphon ;  this, 
when  weighed,  is'  placed  inside  the  Soxhlet 
reservoir,  Fig.  70,  connected  at  the  top  with  the 
lower  end  of  the  reflex  condenser,  C,  and  at  the 
bottom,  6,  with  the  flask  for  receiving  the  fatty 
solution.  The  weight  of  substance  left  after 
removal  of  oil  can  thus  be  determined  by  simply 
reweighing  A. 

Many  other  forms  of  extraction  apparatus  have 
been  devised  and  recommended  by  various  experi- 
menters for  the  quantitative  determination  of  but- 
ter fat  in  milk  residues,  and  such  like  purposes. 

Fig.  71  represents  a  convenient  arrangement  on  the  principle 
of  Soxhlet's  tube  for  the  laboratory  extraction  of  oleaginous 
matter  from  somewhat  larger  quantities  of  material. 

Fig.  72  represents  a  modification  useful  for  extracting  unsapo- 
nifiable  matters  from  liquids — e.g.,  the  alcoholic  soap  solutions- 
obtained  by  saponifying  oils  with  alcoholic  potash.  The  liquid 
is  placed  in  the  extraction  vessel,  A,  which  contains  a  number  of 
glass  beads ;  the  condensed  solvent  (light  petroleum  spirit)  drops 
into  the  funnel,  B,  rises  up  between  the  beads,  washing  out 
soluble  matters  from  the  liquid,  and  overflows  into  the  distilla- 
tion flask,  E,  down  the  side  tube,  h.j 

*  Zeitsckrift  fur  anyewanflte  Chemie,  1889,  p.  242. 

t  Hcnig  &  Spitz,  Journ.  Soc.  Chem.  Imt.,  1891,  p.  1039  ;  from  Zeitsch.  f, 
angziu.  (Jhertue,  1S91,  19,  p.  £05. 


Fig.  69. 


240 


OILS,    FATS,    WAXES,    ETC. 


Some  kinds  of  seeds  contain  a  notable  proportion  of  substances 
soluble  in  ether,  other  than  fatty  matters  —  e.g.,  phytosterol 
(p.  17)  and  lecithin  (or  a  mixture  of  lecithins) ;  the  latter,  con- 


Fig.  70. 


Fig.  71. 


Fig.  72. 


taining  phosphorus,  may  be  estimated  by  determining  the  quan- 
tity of  that  element  contained  in  the  ether  extract  (p.  124). 

The  following  table  is  abbreviated  from  a  larger  one  given  by 
Schadler,*  representing  the  usual  proportions  of  total  oily  or 
fatty  matter  yielded  by  seeds,  nuts,  etc.,  of  various  kinds  on 
extraction  by  solvents  : — 

*  [7nlerxucJtitngen  der  Fette  Ode  und  Wachsarfen,  1889,  p,  4. 


PROPORTION  OF  FATTY  MATTER  CONTAINED  IN  SEEDS,  ETC.  241 


243 


OILS,    FATS,    WAXES,    ETC. 


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PROPORTION  OP  FATTY  MATTER  CONTAINED  IN  SEEDS,  ETC.  243 


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244 


OILS,    FATS,    WAXES,    ETC. 


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ANIMAL    FATS.  245 


CHAPTER  X. 

ANIMAL  FATTY  TISSUE :  EXTRACTION  OF  OILS  AND 
FATS  THEREFROM. 

THE  "  adipose  tissue  "  (ordinarily  known  as  "  fat ")  of  the  higher 
animals  varies  considerably  in  consistence  in  different  cases,  but 
uniformly  consists  of  a  cellular  or  honeycomb-like  structure  of 
nitrogenous  non-fatty  matter,  the  interstices  of  which  are  more 
or  less  filled  with  the  true  non-nitrogenous  fatty  material ; 
hence  mechanical  or  chemical  processes  are  requisite  to  separate 
the  two,  just  as  in  the  case  of  vegetable  oil-containing  seeds,  &c. 
In  some  cases  the  melting  point  of  the  animal  fat  or  oil  is  so 
low  that  processes  of  expression  are  applicable  at  the  ordinary 
temperature,  as  in  the  case  of  certain  fish  livers  (cod  liver  oil,  &c.) ; 
either  the  fresh  organ  being  used,  or  livers  that  have  been  stored 
until  partial  decomposition  has  set  in,  more  or  less  rupturing  the 
oil  cells.  In  other  cases,  the  temperature  requires  to  be  raised 
in  order  that  the  fatty  matter  may  become  sufficiently  fluid  to 
exude,  as  in  the  "rendering"  of  tallow  and  lard;  for  this 
purpose  the  adipose  tissue  may  either  be  subjected  alone  to 
heat,  or  may  be  steamed  or  boiled  with  water  at  the  ordinary 
pressure  or  in  digesters,  or  may  be  treated  with  hot  or  cold 
solvents  for  the  fat,  or  with  substances  acting  chemically  on  the 
nitrogenous  matter  of  the  cell- walls,  and  thus  tending  to  liberate 
the  fat.  When  the  nitrogenous  matter  is  required  to  be  saved 
in  a  solid  form  for  manure  making,  the  manufacture  of  dog- 
biscuit,  pig  feeding,  or  other  purposes  according  to  its  quality, 
the  first  method  may  be  employed,  care  being  taken  to  prevent 
burning  by  overheating  if  free  fire  is  used ;  or  the  fatty  tissue 
may  be  heated  in  a  closed  vessel  by  means  of  steam  and  a 
minimum  of  water ;  or  it  may  be  minced  fine  and  placed  on 
sloping  trays  in  a  chamber  heated  by  steam,  so  that  the'  fatty 
matter  gradually  runs  away  from  the  solid  nitrogenous  cellular 
tissue.  If,  on  the  other  hand,  the  saving  of  the  nitrogenous 
matter  in  the  solid  form  is  of  no  consequence,  the  comminuted 
fat  may  be  heated  for  some  time  with  water  in  a  digester  under 
4  or  5  atmospheres  pressure ;  by  this  means  a  considerable  pro- 
portion of  the  nitrogenous  tissue  is  gelatinised  and  dissolved  as  a 
sort  of  glue,  utilised  either  as  such  or  for  manure  making.  In 
extracting  fat  from  bones  this  process  is  generally  employed; 
on  the  other  hand,  when  the  carcases  of  slaughtered  horses,  &c., 
are  treated,  long  continued  boiling  in  open  pans  under  ordinary 


246  OILS,    FATS,    WAXES,    ETC. 

pressure  is  more  usually  adopted,  the  fat  being  skimmed  off  from 
time  to  time  as  it  rises.  Sometimes  a  small  quantity  of  soda,  or 
of  sulphuric  acid,  is  added  to  the  water  with  which  rough  fats 
are  boiled,  with  the  object  of  attacking  the  cell  walls,  and 
liberating  the  fatty  matter  more  rapidly.  A  certain  amount  of 
loss  by  saponification  takes  place  when  soda  is  thus  used  (unless 
the  impure  soap  formed  is  collected  and  utilised) ;  whilst  hydro- 
lysis of  glycerides  (p.  7)  is  apt  to  be  brought  about  by  the 
action  of  acid,  so  that  the  resulting  fat  contains  free  fatty 
acids  interfering  with  its  use  for  certain  purposes — e.g.,  the 
manufacture  of  some  kinds  of  lubricants.  In  the  Mege-Mouries 
process  for  preparing  oleomargarine  of  best  quality  (vide  Chap, 
xiv.),  a  sort  of  artificial  digestion  of  the  nitrogenous  matter 
is  brought  about,  chopped  suet  being  warmed  with  minced 
sheep's  stomachs  and  a  little  potassium  carbonate,  so  as  to  pep- 
tonise  the  albuminoids  of  the  tissue  and  liberate  the  fatty 
matter;  a  much  purer  product  is  thus  obtained,  owing  to  the 
comparatively  low  temperature  employed  (about  45°  C.)  than  is 
possible  with  any  boiling  process. 

Rendering  of  Fatty  Tissues  by  Dry  Fusion. — W7hen  rough 
fats  from  the  ox,  sheep,  pig,  &c.,  are  minced  fine  and  gently 
heated,  the  melted  grease  gradually  runs  away  from  the  solid 
cellular  tissue.  In  the  manufacture  of  butter  substitutes  (oleo- 
margarine) finely  chopped  beef  suet  is  sometimes  thus  heated  to 
a  temperature  only  just  sufficient  to  partially  fuse  the  fatty 
matter,  and  the  runnings  subsequently  treated  so  as  to  separate 
the  mass  into  a  solid  stearine,  and  a  buttery  mass  largely  con- 
sisting of  oleine.  Owing  to  the  low  temperature  employed, 
50°  to  55°  C.,  noxious  vapours  are  not  evolved  at  all  during  the 
process,  especially  as  none  but  the  freshest  fatty  matter  is  used, 
any  admixture  of  slightly  tainted  material  greatly  depreciating 
the  value  of  the  product. 

When  higher  temperatures  (above  100°  C.)  are  used,  the  rough 
fats  being  heated  over  a  free  fire  with  continual  stirring,  the 
moisture  present  is  evaporated,  and  the  nitrogenous  tissue 
gradually  dries  up  and  shrivels ;  the  oil  cells  are  thus  ruptured, 
and  the  melted  fat  escapes.  The  heat  usually  causes  a  con- 
siderable amount  of  decomposition  of  the  tissue,  leading  to  the 
evolution  of  most  atrocious  smells,  especially  if  the  fatty  tissue  is 
stale,  tainted,  or  partly  decomposed.  By  straining  off  the  melted 
fat,  and  pressing  the  residual  "  greaves  ';  or  "  cracklings,"  in  such 
a  press  as  is  indicated  by  Figs.  34,  38,  or  39  (pp.  202,  205,  206),  the 
majority  of  the  fat  present  is  extracted ;  if  the  cracklings  are  in- 
tended as  food  (for  dogs  or  pigs)  the  presence  of  a  little  residual 
fat  therein  is  an  improvement  rather  than  otherwise;  if  required, 
a  further  amount  of  grease  can  be  extracted  by  boiling  with  dilute 
sulphuric  acid,  or  heating  in  a  pressure  vessel,  so  as  partly  to 
gelatinise  the  solid  animal  matter  and  liberate  the  remaining  fat. 


RENDERING    BY    DRY   FUSION.  247 

An  improved  dry  heat  rendering  arrangement  has  been 
patented  by  Merryweather  &  Sons,  in  which  the  materials  to 
be  rendered  are  placed  in  a  steam  jacketted  pan  into  the  jacket 
of  which  superheated  steam  is  passed,  so  that  the  danger  of 
"  burning "  the  fat  is  greatly  lessened,  whilst  the  heat  can  be 
much  more  easily  regulated ;  accidents  from  fire  through  the  pan 
contents  suddenly  foaming  over  can  be  minimised,  whilst  fuel  is 
economised,  and  the  wear  and  tear  of  the  pan  lessened. 

The  blubbers  of  the  whale,  seal,  dugong,  porpoise,  and  other 
cetacea,  and  the  livers  of  the  shark,  cod,  dogfish,  kulp,  and  other 
fish,  are  generally  allowed  to  remain  in  baskets  or  other  perfor- 
ated vessels  at  the  ordinary  temperature  for  some  time,  so  that  a 
first  running  of  purer  oil  may  be  obtained  spontaneously ;  later 
on  heat  is  applied  to  facilitate  the  extraction.  Formerly  "  boil- 
ing down "  whale  blubber  for  train  oil  was  an  operation  per- 
formed on  the  whaling  vessel  shortly  after  the  capture  of  the 
animal ;  at  the  present  day  the  blubber  is  more  frequently 
brought  ashore  (either  to  port  or  to  fishing  stations  for  the  pur- 
pose) for  treatment.  A  certain  amount  of  oil  is  generally 
collected  by  the  simple  process  of  placing  the  cut  up  mass  in 
racks,  from  which  the  oil  drips  gradually  into  casks ;  later  on 
decomposition  commences,  and  the  oil  then  exuding  is  inferior  in 
quality.  Finally,  the  remaining  mass  is  "boiled"  —i.e.,  sub- 
jected to  dry  heat  to  extract  the  remaining  oil.  In  some  cases 
wet  steam  heating  (infra)  is  applied  at  first,  whereby  the  process 
is  much  shortened. 

In  order  to  mitigate  the  nuisance  arising  from  the  emanation 
of  foul  smelling  vapours  during  the  dry  process  for  rendering 
fats,  (fee.,  various  contrivances  have  been  tried  from  time  to 
time,  such  as  passing  the  evolved  vapours  through  layers  of 
charcoal  or  through  scrubbers  containing  alkaline  or  acid  solu- 
tions, *&c. ;  the  only  really  effective  method,  however,  depends  on 
the  destruction  by  combustion  of  the  malodorous  emanations, 
the  fumes  and  vapours  evolved  being  collected  by  a  hood  or  pipe 
and  made  to  traverse  the  fireplace  of  one  of  the  works'  boilers ; 
or  otherwise  similarly  consumed.  Preferably  the  vessels  are 
enclosed  in  a  sort  of  casing,  so  that  the  vapours  evolved  are  led 
away  by  means  of  a  pipe  to  the  spot  where  they  are  consumed, 
an  indraught  being  maintained  by  means  of  a  fan  or  steam  jet. 

Rendering  of  Fatty  Tissues  by  Heating  with  Water  or 
Steam  under  ordinary  Atmospheric  Pressure. — The  ex- 
traction of  fatty  matter  from  adipose  tissue  is  often  greatly 
facilitated  by  mincing  the  tissue  fine,  or  crushing  it  between 
rollers,  and  then  placing  it  in  a  pan  with  water,  the  temperature 
of  which  can  be  raised  as  required,  either  by  injecting  wet  steam, 
employing  a  dry  steam  coil  or  steam  jacket,  or  by  means  of  free 
fire,  &c.  For  the  preparation  of  oleomargarine  a  process  of  this 
description  is  often  used  as  the  first  stage,  selected  fresh  fat  of 


248  OILS,    FATS,    WAXES,    ETC. 

highest  quality  being  chosen,  and  the  temperature  being  kept  as 
low  as  possible,  consistent  with  the  melting  out  of  the  more 
fusible  constituents  which  rise  to  the  top  and  are  skimmed  off. 
Latterly,  a  higher  temperature  is  used,  whereby  a  more  solid  fat 
(when  cold)  is  obtained;  and,  finally,  the  heat  is  raised  to  100* 
to  extract  the  last  portions  of  fatty  matter.  This,  however,  is 
rarely  completely  effected  unless  either  a  higher  temperature 
(under  pressure)  is  applied  so  as  largely  to  gelatinise  the  nitro- 
genous tissue,  or  sulphuric  acid  is  added  so  as  to  break  up  the  fat 
cells  by  its  solvent  action  on  the  nitrogenous  matter.  In  the 
extraction  of  fat  from  bones  boiling  in  open  pans  for  some 
twenty-four  hours  with  simple  water  is  often  employed,  the 
bones  being  broken  up  into  lumps  so  as  to  expose  the  fat  cells 
as  much  as  possible;  the  fat  is  skimmed  off  as  it  rises,  and  the 
liquor  utilised  for  the  preparation  of  size ;  a  larger  yield  of  fat, 
however,  is  obtained  when  high  pressure  vessels  are  employed 
(vide  infra,  p.  251). 

Various  fish  oils  are  extracted  by  similar  processes ;  thus,  in 
the  preparation  of  cod  liver  oil,  the  fresh  healthy  livers  are  first 
placed  in  open  barrels,  so  that  a  certain  proportion  of  oil 
spontaneously  exudes ;  after  a  while  they  are  transferred  to 
metal  pans,  heated  gluepot  fashion  in  a  larger  external  hot 
water  vessel,  or  by  a  steam  jacket ;  here  a  further  separation  of 
oil  ensues,  of  second  quality.  Finally,  the  livers  are  boiled  with 
water,  when  a  still  lower  grade  separates.  According  to  the 
temperature  employed  in  the  first  heating,  the  quality  of  the 
second  runnings  varies ;  when  40°  to  50°  C.  is  not  exceeded,  a 
much  finer  oil  is  obtained  than  when  75°  to  80°  is  reached,  more 
nearly  approximating  to  the  first  runnings  ("  cold  drawn"  oil), 
but  possessing  a  more  marked  brownish  yellow  tinge.  Oil 
extracted  by  boiling  with  water  is  usually  of  a  more  or  less  deep 
brown  hue. 

According  to  P.  Moller,  of  Christiania,*  the  fishy  unpleasant 
flavour  of  cod  liver  oil  is  largely  due  to  the  absorption  of  oxygen 
during  its  extraction,  and  may  consequently  be  to  a  considerable 
extent  avoided  by  rendering  the  livers  in  vessels  from  which  all 
atmospheric  air  is  excluded  by  means  of  a  current  of  indifferent 
gas,  such  as  hydrogen  or  carbon  dioxide. 

Several  species  of  fish  of  the  herring  and  sardine  class  are 
employed  in  different  countries  as  sources  of  oil,  the  simplest 
method  of  procedure  adopted  being  to  slice  and  mash  the  fish, 
and  pour  boiling  water  over  the  mass,  which  is  then  stored 
in  barrels,  &c.,  for  some  time ;  decomposition  sets  in,  and  the  fat 
tissues  become  disintegrated,  so  that  the  oil  floats  up  and  is 
skimmed  off  at  intervals,  A  more  systematic  method,  adopted 
in  the  case  of  menhaden  oil  and  other  fish  oils  extracted  by 
means  cf  modernised  appliances,  consists  in  thoroughly  boiling 
*  English  patent,  No.  13,803,  1890. 


BOILING   PROCESSES.  249 

or  steaming  the  fish  (whole  and  unbroken,  or  sliced  and  mashed), 
and  then  subjecting  to  comparatively  gentle  pressure ;  the  first 
runnings  thus  obtained  are  considerably  superior  to  the  second 
grade,  prepared  by  boiling  or  steaming  the  residue  a  second  time, 
and  pressing  again  with  stronger  pressure,  and  at  a  higher 
temperature;  the  screw  press  heated  by  steam,  shown  in  Fig.  38, 
p.  205,  is  well  adapted  for  this  process.  The  ultimate  residue  is 
utilised  for  manure  :  after  being  squeezed  as  dry  as  possible, 
preferably  by  hydraulic  pressure,  the  residual  solid  mass  is 
broken  up  and  allowed  to  ferment,  dried  somewhat,  ground  and 
.sifted,  and  finally  dried  further,  so  as  to  form  a  powder 
convenient  for  transport.  Large  quantities  of  fish  manure  are 
thus  prepared  from  the  residues  of  the  extraction  of  oil  from  the 
"  menhaden  "  or  "  porgie  "  at  numerous  places  along  the  North 
American  Atlantic  coast. 

D'Arcet's  sulphuric  acid  process  for  rendering  tallow  consists  in 
melting  the  adipose  tissue  with  from  one  fifth  to  half  its  weight 
of  water,  and  a  few  per  cents,  of  sulphuric  acid,  keeping  the 
entire  mass  boiling  until  the  separation  of  fat  is  completed,  the 
heat  being  applied  by  means  of  a  free  fire,  by  a  steam  jacket,  or 
by  directly  blowing  in  steam  ;  in  the  latter  case,  somewhat  less 
water  is  originally  added,  with  a  proportionate  increase  in 
sulphuric  acid  strength,  to  compensate  for  dilution  by  condensa- 
tion of  steam.  When  this  method  is  adopted,  the  vessel  may  be 
simply  constructed  by  lining  a  cask  or  tank  with  sheet  lead; 
whereas,  for  boiling  over  free  fire,  a  copper  vessel  must  be 
employed,  iron  being  too  readily  attacked  by  the  acid.  In 
Evrard's  process  the  sulphuric  acid  is  replaced  by  caustic  soda ; 
the  evolution  of  foetid  smells  is  thereby  lessened,  but  loss  is  apt 
to  be  occasioned  through  the  formation  of  soap  by  the  action  of 
the  soda  on  the  fat. 

When  rough  fats  are  rendered  in  a  soapery  for  use  therein,  a 
simple  method  of  procedure  is  to  place  the  tissues  to  be  treated 
in  one  of  the  soap  "kettles"  or  "coppers"  (Chap,  xix.),  and  blow 
wet  steam  through  the  mass ;  a  large  proportion  of  the  fatty 
matter  is  then  melted  down,  and  is  removed  by  skimming.  To 
extract  the  remainder,  weak  alkaline  leys  from  other  operations 
are  run  in,  and  the  whole  boiled  up  with  steam  so  as  to  convert 
the  fat  into  a  kind  of  impure  soap  solution,  which  is  run  off  and 
worked  up  along  with  other  inferior  material  in  the  manufacture 
of  lower  grades  of  scouring  soaps. 

When  partly  decomposed  tissues,  (fee.,  are  boiled  to  extract  fat, 
much  the  same  kinds  of  noxious  smells  are  apt  to  be  evolved  as  in 
the  dry  process  (p.  247);  accordingly,  when  it  is  essential  to  avoid 
nuisance,  it  is  usual  to  box  in  the  pans,  and  lead  the  evolved 
vapours  to  a  condensing  chamber  where  the  steam  is  condensed, 
the  remaining  air,  itc.,  being  drawn  off  to  the  main  chimney 
stalk  of  the  works,  by  which  means  a  continuous  indraught  is 


250 


OILS,    FATS,    WAXES,    ETC. 


set  up,  and  outward  leakage  of  malodorous  vapours  avoided.  In 
the  case  of  putrid  materials,  the  mere  dilution  of  noxious  vapours 
with  the  chimney  gases  thus  brought  about  is  not  always 
sufficient,  and  destruction  of  smell  by  fire  must  be  resorted  to  in 
order  to  avoid  nuisance  in  certain  situations,  such  as  crowded 
towns,  and  the  like. 

Hendering  under  Increased  Pressure.  —  Of  all  processes 


Fig.  73. 

for  obtaining  fats  from  their  natural  animal  sources  this  one  is 
the  most  extensively  used,  as  the  higher  temperature  attained 
leads  to  the  more  complete  gelatinisation  of  nitrogenous  tissue, 
and  consequently  to  the  more  thorough  separation  of  fat.  Fig.  73 
represents  a  digester  employed  in  Wilson's  process  for  rendering 


RENDERING    UNDER    PRESSURE.  251 

tallow  and  lard ;  a  series  of  these  is  generally  worked  together, 
each  of  10,000  or  15,000  gallons  capacity,  or  even  more.  In 
large  American  slaughterhouses  (e.g.,  at  Chicago,  St.  Louis, 
Cincinnati,  <tc.),  each  digester  is  kept  for  the  production  of  one 
kind  of  fatty  matter  only,  the  adipose  tissue  being  usually 
worked  up  therein  within  a  few  minutes  after  slaughtering ; 
hence  injury  through  use  of  stale  or  decomposed  fatty  tissue  is 
avoided,  and  extremely  uniform  grades  of  lard  and  tallow  ob- 
tained, the  various  portions  of  the  carcases  being  separately 
treated  in  different  vessels  according  to  the  part  of  the  body 
employed.  The  boiler  is  provided  with  a  false  bottom  ;  a  dis- 
charging orifice,  E,  covered  when  required  by  a  plate,  F,  raised 
or  lowered  as  required  by  the  rod,  G,  passing  through  a  stuffing 
box  ;  an  internal  steam  coil  at  the  base  fed  with  steam  from  an 
ordinary  boiler  by  the  pipe,  "V,  and  steam  cock,  B  ;  and  a  series 
of  draw-off  cocks  at  the  side,  TJ,  p,  j),  p,  p,  R.  A  safety  valve,  O, 
is  also  provided,  and  a  manhole  at  the  top,  K.  The  discharging 
valve  being  closed  by  lowering  F,  the  fat  to  be  rendered  is 
introduced  through  the  manhole,  K,  until  within  2  to  2^- feet  of 
the  top ;  the  manhole  being  closed  steam  is  admitted  through 
the  cock,  B,  until  the  desired  pressure  is  obtained  (usually  3  to 
4  atmospheres).  Much  water  condenses  during  the  heating  up ; 
if  requisite  this  is  drawn  off  from  time  to  time  by  means  of  the 
lowest  cock,  U,  the  progress  of  the  fusion  being  tested  and 
regulated  by  opening  the  top  cock,  R,  so  as  to  see  whether  steam 
only  escapes,  or  melted  fat.  After  ten  to  fifteen  hours  the  steam 
supply  is  shut  off  and  the  excess  pressure  relieved  by  opening 
the  safety  valve  ;  the  whole  is  then  allowed  to  remain  at  rest 
<i while  so  that  the  fatty  matter  and  water  may  separate,  when 
the  former  is  drawn  off  into  coolers  through  the  side  cocks, 
Pi  Pi  Pi  Pi  and  the  latter  through  the  lowest  cock,  U.  The  aque- 
ous liquor  contains  much  nitrogenous  'matter  in  solution  and  is 
utilised  for  manurial  purposes.  The  boiler  is  finally  discharged 
of  solid  contents  by  raising  the  valve,  F  ;  the  matters  ejected  are 
collected  in  a  tub,  T,  and  if  not  completely  freed  from  fat  are 
returned  to  the  boiler  and  worked  over  again  with  the  next 
charge. 

Extraction  of  Fat  from  Bones. — Before  bones  are  treated 
for  the  preparation  of  manure,  animal  charcoal,  &c.,  the  fatty 
matters  contained  therein  are  usually  more  or  less  completely 
extracted  by  one  or  other  of  a  variety  of  processes  ;  of  these  the 
simplest  consists  in  boiling  the  bones  (preferably  crushed  into 
coarse  fragments)  with  water  heated  by  a  steam  jet  or  otherwise; 
the  fatty  matters  are  thus  melted  out  and  obtained  by  skimming 
off  as  they  rise  to  the  top  of  the  water.  A  large  fraction  of  the 
total  fatty  matter  is  thus  left  behind  in  the  osseous  tissue  through 
incomplete  removal ;  a  better  yield  is  obtained  when  the  heating 
is  effected  under  increased  pressure  in  a  digester,  the  steam  then 


252 


OILS,    FATS,    WAXES,    ETC. 


penetrating  into  the  minute  cavities  and  more  completely  dis- 
placing the  melted  fat ;  moreover,  the  nitrogenous  cell  wall  con- 
stituents are  usually  gelatinised  to  a  greater  extent  than  is 
effected  by  open  pan  boiling,  so  as  to  facilitate  the  escape  of  fat ; 
for  this  same  reason,  however,  the  bones  thus  treated  are  ren- 
dered poorer  in  organic  constituents,  and,  therefore,  less  suitable 
as  manure  or  for  animal  charcoal  making ;  on  the  other  hand, 
more  soluble  organic  matter,  suitable  for  glue  making  or  for 
manure,  tfcc.,  is  obtained  in  the  watery  liquor. 

Various  forms  of  digester  are  in  use  ;  a  useful  variety  consists 
of  a  vertical  wrought  iron  barrel  or  cylinder  some  6  feet  long  and 

3  feet  6  inches  diameter,  slightly 
tapering  at  each  end,  and  fitted  with 
flanges  to  which  iron  discs  can  be 
bolted  (Fig.  74).  The  upper  plate, 
b,  serves  as  lid,  so  that  when  re- 
moved fresh  bones  can  be  introduced ; 
the  lower  one,  .c,  is  slightly  curved ; 
when  removed  the  boiled  bones  are 
discharged.  A  charge  of  2  to  2J  tons 
of  crushed  bones  being  introduced  the 
plates  are  bolted  on  steamtight,  the 
operation  being  facilitated  by  fasten- 
ing the  plates  on  with  hinges  so  that 
they  are  virtually  doors.  Steam  at 
3J  to  4  atmospheres  pressure  (56  to 
65  Ibs.)  is  then  introduced  for  about 
three-quarters  of  an  hour ;  wrhen  shut 
off  the  pressure  is  relieved,  and  the 
whole  allowed  to  stand  for  half  an  hour,  when  the  condensed 
water  and  melted  fat  are  drawn  off  through  a  tap,  /,  in  the 
bottom  plate  or  door.  This  door  is  then  opened  and  the  ex- 
hausted bones  removed,  after  which  a  fresh  charge  is  intro- 
duced and  worked  off  as  before.  Even  when  operating  in  this 
way  a  certain  amount  of  fatty  matter  is  still  left  in  the  bones  ; 
to  avoid  this,  in  some  Continental  factories  solvents  are  used 
(carbon  disulphide,  benzene,  light  petroleum  distillate,  &c.),  the 
mode  of  treatment  being  very  much  the  same  as  that  adopted 
for  the  similar  extraction  of  grease  from  vegetable  marcs,  engine 
waste,  &c.  (vide  p.  236) ;  the  crushed  bones  being  placed  in  suit- 
able vessels  into  which  the  solvent  is  run,  preferably  traversing 
several  in  succession,  and  the  fatty  solution  being  subsequently 
distilled  to  recover  the  solvent  and  obtain  the  grease. 

Owing  to  the  peculiar  texture  of  bone  as  compared  with 
vegetable  seeds,  even  this  mode  of  treatment  does  not  produce 
a  perfect  solution  and  removal  of  all  the  fatty  matters  present ; 
in  order  to  obtain  a  larger  yield,  various  modifications  of  the 
plant  have  been  introduced,  whereby  the  solvents  are  made  to 


Fig.  74. 


EXTRACTION  OF  FAT  FROM  BONES. 


253 


act  on  the  crushed  bones  in  the  form  of  vapour.  In  one  form  of 
apparatus,  this  is  effected  under  increased  pressure  (after  pump- 
ing out  all  atmospheric  air  from  the  vessel  employed),  so  that  the 
solvent  enters  thoroughly  into  the  pores  of  the  bone  fragments, 
and  being  attracted  to  and  condensed  by  the  fatty  matters,  forms 
a  fluid  solution  of  fat  which  exudes  and  runs  down  to  the 
bottom,  and  is  subsequently  distilled  (Seltsam's  process).  In. 


another  form  the  crushed  bones  are  permeated  with  a  mixture 
of  steam  and  vapour  of  solvent,  which  is  condensed  by  a  worm 
so  as  to  drop  down  again  upon  the  bones  and  percolate  through 
them  to  a  false  bottom,  where  the  solvent  is  again  volatilised 
by  a  steam  coil,  the  whole  arrangement  being  not  unlike  that 
used  for  cleansing  engine  waste  (Fig.  65,  p.  237).  Fig.  75  re- 
presents Leuner's  apparatus  arranged  on  this  principle  (Schadler). 


254:  OILS,    FATS,    WAXES,    ETC. 

The  crushed  bones  are  placed  in  A  above  the  perforated  false 
bottom,  B.  C  is  a  steam  pipe,  by  means  of  which  the  bones  are 
steamed  as  a  preliminary,  the  surplus  steam  escaping  through 
the  exit  pipe  D.  After  steaming,  water  and  benzene  are  run  in 
from  the  reservoir,  F,  into  the  space  under  the  false  bottom,  and 
heated  up  by  the  steam  coil,  P.  The  evolved  vapours  are  con- 
densed in  the  worm,  K,  and  at  first  run  back  over  the  bones 
through  the  cock,  L,  the  vapour  passing  upwards  to  the  worm 
through  J,  and  the  condensed  liquid  being  divided  into  separate 
streams  by  the  spreading  plate,  O.  After  some  time  the  cock, 
G,  is  opened,  so  that  the  condensed  liquid  runs  into  the  reser- 
voir, F,  instead  of  flowing  back  into  A.  When  all  the  solvent 
has  been  volatilised,  nothing  but  water  condenses  in  the  worm, 
which  is  known  by  means  of  a  sampling  cock  attached  to  J ;  the 
draw  off  cock,  E,  is  then  opened,  and  the  watery  gelatine  solu- 
tion and  oily  matter  run  off  into  a  suitable  separating  receptacle  ; 
A,  is  then  discharged  through  a  manhole  and  refilled,  and  the 
whole  operation  repeated. 

Another  method  of  operating  is  to  introduce  the  crushed  bones 
into  a  sufficiently  strong  false-bottomed  vessel,  from  which  the 
air  is  then  pumped.  Benzene,  carbon  disulphide,  or  other  con- 
venient volatile  solvent  is  then  run  in  until  the  vessel  is  filled, 
whereby  the  solvent  fluid  is  driven  thoroughly  into  the  pores  of 
the  bone  tissues.  By  drawing  off  most  of  the  fluid  and  then  again 
exhausting,  the  solvent  is  to  a  great  extent  volatilised ;  and  by 
readmitting*  air  the  vapour  is  again  condensed  by  the  increased 
pressure  so  as  to  wash  out  the  fat  solution  from  the  bone  frag- 
ments. This  solution  runs  down  to  the  base  of  the  vessel,  and 
is  ultimately  distilled  by  working  the  air  pump,  leaving  the  fat 
whilst  the  vapour  of  the  solvent  pumped  out  is  condensed  by 
cooling  and  used  over  again.* 


CHAPTER  XI. 

REFINING  AND  BLEACHING  ANIMAL  AND  VEGETABLE 
OILS  AND  FATS,  WAXES,  &c. 

SUSPENDED  MATTERS. 

OILS  and  fats  as  obtained  by  many  of  the  processes  in  ordinary 
use  contain  various  impurities  partly  in  suspension,  partly  in 
solution.  Of  these  the  most  objectionable  are  the  gummy 

*  For  further  details  of  bonefat  extracting  plant  vide  Schadler,  Technologic 
der  Fette  und  Oete,  2nd  Edition,  edited  by  Lohmaun,  p.  9_'8,  et.  seq.  Also 
for  Seltsam's  process,  Journ.  Soc.  Chem.  Ind.,  1882,  p.  112. 


CLARIFICATION.  255 

mucilaginous  or  albuminous  matters  which  generally  accompany 
expressed  oils  and  rendered  fats  to  a  greater  or  lesser  extent, 
because  unless  speedily  removed  they  are  apt  to  undergo 
fermentative  or  putrefactive  changes,  which  not  only  induce 
hydrolysis  of  the  glycerides  (p.  10)  but  also  charge  the  oil  with 
malodorous  bye-products  of  decomposition,  rendering  the  oil 
"rancid."  Substances  of  this  kind  are  usually  chiefly  in  suspen- 
sion in  the  oil ;  so  that  by  passing  the  freshly  expressed  oil 
through  a  filterpress  (p.  228),  a  considerable  proportion  of  the 
suspended  matter  is  removed,  rendering  the  oil  in  many  cases 
sufficiently  clear  and  free  from  visible  impurities  to  be  at  once 
saleable.  Sometimes,  however,  the  suspended  matter  is  present 
in  a  form  where  filtration  alone  produces  only  an  insufficient 
amount  of  purification,  and  where  even  prolonged  standing  does 
not  efficiently  clarify  the  oil  by  subsidence ;  this  happens  more 
especially  when  the  mucilaginous  matter  is  disseminated  through- 
out the  oil  in  a  sort  of  highly  diluted  jelly-like  condition,  some- 
what analogous  to  colloidal  gelatine  or  thin  starch  paste,  where 
the  constituent  particles  are  mostly  too  fine  to  be  stopped  by 
means  of  ordinary  porous  filtering  media,  or  to  gravitate  rapidly. 
In  such  cases  special  mechanical  or  chemical  treatment  must 
be  resorted  to  in  order  to  coagulate  the  mucilaginous  matter : 
sometimes  simply  heating  produces  this  effect,  the  albuminous- 
substances  being  solidified  and  coagulated  somewhat  like  white 
of  egg.  This  is  conveniently  effected  by  blowing  steam  through 
the  oil  by  means  of  a  fine  rose  jet ;  the  condensation  of  water 
facilitates  the  action  as  the  coagulated  albuminous  matter  attracts 
moisture  and  becomes  increased  in  bulk  and  deposits  more  readily 
as  a  flocculent  precipitate  on  standing.  The  addition  of  small 
quantities  of  various  chemicals  often  produces  an  analogous  effect ; 
thus  a  small  percentage  of  sulphuric  acid,  or  of  concentrated  zinc 
chloride  solution  (sp.  gr.  1*65),  well  agitated  with  the  oil  causes 
on  standing  the  gradual  deposition  of  mucilage,  along  with  most 
of  the  acid,  the  rest  being  subsequently  removed  by  agitation 
with  water.  Oils  containing  resinous  matter  (e.g.,  cotton-seed 
oil)  as  well  as  mucilage  are  preferably  refined  by  similar  treat- 
ment with  alkalies,  the  resin  being  thereby  dissolved  out  and 
removed  as  well  as  vegetable  mucus. 

The  purely  physical  action  exerted  by  particles  of  suspended 
matter  as  regards  attracting  the  colloidal  mucilage  often  serves 
to  remove  the  latter ;  thus  clay,  fuller's  earth,  sand,  particles  of 
oilcake,  powdered  charcoal,  and  similar  materials,  when  well 
agitated  with  the  oil  or  melted  fat  to  be  treated,  tend  to  unite 
with  the  mucilage,  in  such  fashion  that  by  allowing  the  whole  to 
subside,  or  by  filtering  it,  the  whole  of  the  suspended  matter  is 
simultaneously  separated.* 

*  In  many  cases  a  very  satisfactory  degree  of  purification  is  readily 
effected  by  b  mply  adding  to  the  mucilaginous  oil,  as  it  runs  from  the  press, 


256  OILS,    FATS,    WAXES,    ETC. 

In  certain  cases  the  addition  of  chemicals  that  combine  with 
the  albuminous  matter  forming  precipitates  answers  the  same 
purpose  ;  thus  oakbark  infusion  and  other  forms  of  tannin  solu- 
tion, when  well  agitated  with  the  oil  to  be  treated,  cause  the 
formation  of  insoluble  tanno-gelatinous  matter  which  precipitates 
on  standing  carrying  down  with  it  most  of  the  colloidal  suspended 
matter.  Various  metallic  salts  (copper  sulphate,  manganese  sul- 
phate, lead  acetate,  <fec.)  are  sometimes  used  with  a  similar  object. 
A  process  of  this  kind  sometimes  used  for  cleansing  rancid  tallow 
is  to  boil  up  with  a  small  quantity  of  soda  ley ;  the  melted 
fat  is  removed  from  the  soap  produced  by  ladling  off,  and  then 
boiled  up  with  a  weak  solution  of  alum ;  after  settling,  the 
purified  tallow  is  again  run  off  and  heated  by  itself  to  150°  C. 
and  upwards,  whereby  it  becomes  greatly  whitened  and  har- 
dened.* 

Dissolved  Matters. — Other  impurities  are  dissolved  in  the 
oil,  and  the  complete  separation  of  these  is  in  many  cases  imprac- 
ticable. Resinous  matters  are  the  commonest  impurities  found 
in  solution ;  these  are  generally  of  a  feebly  acid  character,  so  that 
agitation  with  small  proportions  of  alkaline  solution  removes  the 
larger  part  or  even  the  whole  of  these.  For  this  purpose  soda, 
potash,  milk  of  lime,  and  calcined  magnesia  are  employed  in 
different  instances  ;  carbonated  alkalies  and  alkaline  earths 
(carbonate  of  soda,  lime,  &c.)  usually  act  only  imperfectly. 
When  the  proportion  of  resin  is  at  all  large  the  saponaceous 
compound  formed  sometimes  separates  only  with  difficulty  from 
the  clarified  oil ;  agitation  with  saline  solutions  (sulphate  of  soda, 
or  common  salt,  <kc.)  in  such  cases  generally  causes  the  mass  to 
separate  into  three  layers  on  standing  :  the  lowest  one  a  watery 
fluid  containing  chiefly  inorganic  salts  in  solution  ;  the  upper- 
most, clarified  oil ;  intermediately,  a  more  or  less  frothy  spumous 
mass  of  "  foots."  Frequently  this  contains  so  much  unaltered  oil 
mechanically  entangled  as  to  be  a  highly  valuable  material  for 
soapmaking,  the  resinous  soap  also  present  usually  not  interfering 
with  this  application. 

Bonefat  extracted  by  boiling  processes  generally  retains  in 
solution  phosphate  of  lime  and  other  calcium  salts  to  an  extent 
greatly  interfering  with  the  preparation  of  soap  from  this  mate- 
rial :  boiling  with  dilute  sulphuric  or  hydrochloric  acid  converts 
the  lime  into  calcium  sulphate  or  chloride,  and  completely 
removes  these  inorganic  dissolved  impurities,  the  operation 
being  very  simply  performed  by  placing  the  fat  in  a  tank  lined 

a  small  quantity  of  cake  parings  ground  up  by  edgestones  (p.  219),  and  then 
passing  the  whole  through  a  lilterpress ;  the  residue  left  in  the  filterpress 
is  returned  to  the  kettle  and  worked  up  with  fresh  crushed  seed,  &c. 
Still  better  clarification  may  often  be  effected  by  heating  the  mixture  of 
oil  and  parings,  so  as  to  coagulate  albuminous  matter,  and  then  passing 
through  the  filterpress. 

*0il  Trade  Review,  Oct.  1884. 


DISSOLVED    IMPURITIES. 


257 


with  sheet  lead  along  with  a  sufficient  quantity  of  highly  diluted 
acid,  and  blowing  wet  steam  through  the  mass  so  as  to  agitate  it 
thoroughly.  Sulphuric  acid  has  the  advantage  of  cheapness  and 
of  acting  less  on  the  lead  than  hydrochloric  acid ;  on  the  other 
hand  insoluble  calcium  sulphate  forms  and  is  deposited,  whereas 
calcium  chloride,  being  readily  soluble,  does  not  separate  in  the 
solid  form. 

Certain  oils  when  chilled  deposit  the  less  readily  fusible  con- 
stituents as  "  stearines  "  (p.  110) ;  on  subjecting  these  to  nitration 
and  pressure,  an  oleine  practically  free  from  suspended  albu- 
minous matters  generally  results,  any  such  impurities  being 
mostly  retained  along  with  the  stearine.  A  partial  separation 
of  stearine  by  allowing  to  stand  at  a  relatively  low  temperature, 
is  accordingly  sometimes  resorted  to  as  a  means  of  clarifying  and 
refining  oils,  more  especially  the  more  expensive  edible  oils 
("  salad "  oils)  ;  the  thickened  mass  being  filterpressed  whilst 
chilled,  or  on  the  small  scale  being  strained  through  rough  filters 
of  moss,  cotton  wool,  charcoal,  &c.,  placed  between  the  perforated 
bottoms  of  two  boxes,  one  just  fitting  inside  the  other.  Oils 
that  have  been  thus  treated  are  sometimes  termed  "  winter  oils  " 
— i.e.,  oils  still  remaining  fluid  in  winter ;  whilst  untreated  oils 
that  become  turbid  or  partially  solidify  on  chilling  and  are  only 
clear  in  warm  situations  are  designated  "  summer  oils." 


Oil  or  Fat. 

Percentage  of 
Unsaponiflable  Matter. 

Allen  &  Thomson 

Schiidler. 

Cotton  seed  oil, 

1-64 

1-85 

Coker  butter,    . 

0-80 

Hempseed  oil,  . 

1-00 

Japanese  wax,  . 

1-14 

1-20 

Cod  liver  oil  (brown), 

1-32 

1-45 

„    (light),  . 

0-46 

0-50 

Linseed  oil, 

1-10 

Almond  oil, 

0-45 

Poppyseed  oil,  . 
Olive  oil  (yellow), 

0:75 

1-15 

0-80 

,,      ,,    (green), 

1-50 

Palm  butter,      . 

1-25 

Rapeseed  oil  (crude), 

1-00 

1-30 

,,         ,,   (refined), 

0-15 

Hog's  lard, 
Tallow,      . 

0-23 

0-30 
0'50 

Even  after  as  complete  a  removal  as  possible  of  suspended 
albuminous  and  mucilaginous  matter  and  of  dissolved  resin,  most 
natural  oils  and  fats  contain  in  solution  small  quantities  of  non- 
saponifiable  nonresinous  matters ;  in  some  cases  cholesterol  or 

17 


258 


OILS,    FATS,    WAXES,    ETC. 


isomerides  thereof  (isocholesterol,  phytosterol,  &c.)  have  been 
identified  as  present — e.g.,  in  olive  oil.  The  figures  quoted  on 
p.  257  are  given  by  Allen  and  Thomson  *  and  Schadler  f  as 
representative  ones  in  various  cases. 

The  folio  wing  figures  were  obtained  by  Thomson  and  Ballantine| 
in  the  course  of  an  extended  examination  of  numerous  samples 
of  oils  : — 


Xame  of  Oil. 

Percentage  of 
TJnsaponifiable  Matter. 

Olive  oil  (13  kinds),      . 

1-04  to  1-42 

Cotton  seed  oil  (crude), 

1-12 

,,             ,,   (refined), 

TO? 

Rape  oil  (Colza,  5  kinds), 

•58  to     '70 

Arachis  oil,  . 

•54  to     -94 

Linseed  oil  (4  kinds),   . 

1-06  to  1-28 

Castor  oil,    . 

•30  to     -37 

Southern  sperm  oil, 

37-41 

Arctic  sperm  oil  (bottlenose  , 

36-32 

Whale  oil  (pale),  . 

1-82 

Seal  oil  (4  kinds), 

•42  to     '51 

Cod  oil  (3  kinds), 

•87  to  1-87 

Menhaden,  . 

1-60 

In  the  analysis  of  soap  (Chap,  xxi.),  as  the  unsaponifiable  sub- 
stances originally  contained  in  the  fatty  matters  employed  for 
the  most  part  pass  into  the  soap  during  manufacture,  a  correction 
on  this  score  is  requisite  when  it  is  desired  to  determine  the 
mean  equivalent  of  the  fatty  acids  present  (p.  172).  According  to 
the  author's  experience  the  amount  of  matters  of  unsaponifiable 
nature  thus  contained  in  100  parts  of  fatty  acids,  &c.,  separable 
from  the  soap  by  means  of  a  mineral  acid  generally  lies  between 
•25  and  I'O  part,  averaging  near  to  '5  to  '75 — i.e.,  in  the  case  of 
soaps  made  from  natural  oils  and  fats,  to  which  no  additional 
unsaponifiable  matters  have  been  intentionally  added.  When 
woolgrease  or  Yorkshire  grease  (Chap,  xn.)  has  been  used,  either 
purposely  as  an  ingredient,  or  unwittingly  in  the  form  of  an 
adulteration  of  tallow,  &c.,  the  proportion  becomes  markedly 
increased ;  with  oleine  soaps  made  from  distilled  oleine  a, 
few  per  cents,  of  hydrocarbons  are  often  present,  formed  during 
the  distillation  of  the  fatty  acids,  smaller  quantities  being  often 
found  in  soaps  made  from  oleines  prepared  in  the  autoclave 
without  distillation.  When  paraffin  oils  have  been  intermixed 
with  the  soap,  as  in  the  case  of  certain  kinds  of  laundry  soaps, 
the  percentage  of  unsaponifiable  matters  is  largely  increased. 

*  Chemical  News,  43,  267. 

t  Technologic  der  Fette  und  Ode,  p.  61. 

$Journ.  Soc.  Chem.  Ind.,  1891,  p.  233. 


OIL    REFINING — ACID    PROCESS.  259 

The  fatty  matters  extracted  by  solvents  from  certain  legu- 
minous plant  seeds  (peas,  lupins,  &c.)  contain  relatively  consider- 
able proportions  of  glycerophosphoric  choline  derivatives  of  the 
nature  of  lecithin  (p.  121) :  the  existence  of  small  quantities  of 
substances  of  this  class  in  oils  expressed  for  commercial  purposes 
is  extremely  probable,  but  little  or  no  knowledge  is  extant  as  to 
how  far  this  is  the  case.  The  husk  of  the  seeds  of  Lupinus  luteus 
yields  to  ether  a  crystallisable  substance,  lupeol,  analogous  to 
cholesterol,  but  derived  from  a  hydrocarbon  poorer  in  hydrogen 
(vide  p.  17) ;  whilst  the  seed  husks  of  PJiaseolus  vulgaris  contain 
a  higher  homologue  of  phenol  (viz.  pliasol,  C15H24O)  together 
with  paraphytosterol  (p.  16);  in  all  probability  several  such 
substances  akin  to  cholesterol  and  phytosterol  are  contained  in 
small  quantities  in  seed  oils. 


SULPHURIC  ACID  PROCESS  FOR  REFINING  OILS,  &c.. 
(THENARD  PROCESS). 

In  employing  sulphuric  acid  as  a  clarifying  agent  it  is  requisite 
that  no  large  excess  should  be  used  otherwise  a  charring  action 
is  apt  to  be  set  up  on  the  oil  itself,  darkening  its  colour  and 
depreciating  its  value.  In  refining  linseed  oil  from  one-hundredth 
to  one-fiftieth  part  (1  to  2  per  cent.)  of  acid*  is  thoroughly  inter- 
mixed with  the  oil  in  an  efficient  agitator  at  a  temperature  not 
exceeding  40°  (about  104°  F.),  and  the  whole  allowed  to  rest  for 
24  hours.  60  to  70  per  cent,  of  warm  water  at  about  60°  C. 
(140°  F.)  is  then  well  intermixed  and  the  whole  allowed  to  stand 
some  days ;  a  watery  acid  liquid  separates  at  the  bottom  with  a 
layer  of  flocculent  "  foots,"  above  which  is  the  clarified  oil,  which 
is  drawn  off  and  again  agitated  with  warm  water  as  before  to 
wash  out  any  residual  suspended  acid  vesicles.  Another  method 
of  operating  (Cogaii's  process)  is  to  use  1  per  cent,  of  acid  diluted 
with  as  much  more  of  water ;  this  is  well  intermixed,  and  after 
standing  some  hours  is  heated  up  to  100°  C.  by  blowing  in  steam 
through  a  fine  rose  jet  at  the  bottom  of  a  copper  vessel.  This 
temperature  is  maintained  for  several  hours,  after  which  the 
whole  is  allowed  to  stand  at  rest  so  as  to  separate  the  watery 
acid  and  foots  from  the  clear  oil.  In  order  to  draw  off  the  oil 
without  disturbing  the  water  and  foots,  a  conical  separating 
vessel  is  generally  employed  with  taps  at  various  levels  so  that 
all  clear  oil  above  a  given  level  can  be  drawn  off  without  disturb- 
ing that  below. 

Rape  (colza)  and  linseed  oils  and  certain  fish  oils  are  those  most 
usually  refined  by  the  acid  process.  Oils  intended  for  lubrication 

*  Hartley  recommends  that  the  acid  should  be  diluted  with  water  before 
mixing  with  the  oil,  so  as  not  to  contain  more  than  30  per  cent,  of  actual 


^60  OILS,    FATS,    WAXES,    ETC. 

are  as  a  rule  the  least  suitable  for  such  treatment,  inasmuch  as 
the  presence  of  free  fatty  acids  (and  a  fortiori  of  possible  traces 
of  mineral  acids)  is  a  serious  objection  with  most  such  substances, 
corrosion  of  bearings  and  shafts,  &c.,  being  apt  to  be  thereby 
occasioned.  For  oils  intended  for  burning  in  lamps  the  presence 
of  any  considerable  amount  of  free  fatty  acids  is  also  objectionable 
as  tending  to  cause  charring  of  the  wick. 

R.  v.  Wagner  recommends  the  use  of  zinc  chloride  solution  of 
sp.  gr.  1-85  instead  of  sulphuric  acid,  using  about  1^  parts  per 
100  of  oil.  Albuminous  impurities  are  equally  destroyed  or 
coagulated,  whilst  there  is  less  danger  of  injurious  action  on  the 
oil  itself.  Hartley  finds  that  a  strong  solution  of  manganese 
sulphate  answers  well. 

ALKALINE  REFINING  PROCESSES. 

As  already  stated,  processes  where  alkalies  are  used  as  agents 
for  coagulating  and  removing  mucus,  albuminoids,  &c.,  have 
several  advantages  over  the  acid  methods,  notably  that  free  fatty 
acids  and  resins  are  also  removed.  The  quantity  and  strength 
of  the  alkaline  ley  employed  varies  with  the  nature  of  the  oil  to 
be  treated ;  any  undue  excess  is  apt  to  lead  to  more  or  less 
considerable  loss,  not  only  by  producing  more  saponification  but 
also  because  the  extra  amount  of  saponaceous  products  gives  rise 
to  the  formation  of  more  foots  containing  clarified  oil  entangled 
therein.  The  requisite  quantity  of  ley  and  the  oil  are  well 
agitated  together  by  any  suitable  mechanical  mixer  (either  in 
the  cold  or  heated  to  the  requisite  temperature,  as  the  case  may 
require),  and  the  whole  then  allowed  to  settle ;  a  heavier  watery 
fluid  with  soapy  foots  separates ;  this  is  drawn  off  and  the  process 
repeated  with  a  much  weaker  alkaline  solution,  and  subsequently 
with  plain  water.  When  considerable  quantities  of  resin  are 
present,  as  in  the  case  of  cotton  seed  oil,  the  ley  may  conveniently 
be  of  sp.  gr.  1-06  up  to  1*10 ;  in  such  cases  it  frequently  happens 
that  the  watery  layer  and  foots  will  not  separate  thoroughly 
from  the  oil  without  the  subsequent  addition  of  a  little  salt 
or  brine.  To  avoid  the  formation  of  emulsions  Hageman 
employs  as  purifying  agent  soda  crystals  heated  to  about 
80°  so  as  to  fuse  in  their  water  of  crystallisation ;  after  inter- 
mixture by  agitation  the  mass  separates  on  standing  into  three 
sharply  defined  layers  of  purified  oil,  soapy  matters,  and  watery 
fluid  respectively,  but  without  any  notable  production  of  emul- 
sion. 

Sometimes  oils  are  required  to  be  treated  that  have  become 
more  or  less  rancid  by  keeping,  owing  to  fermentative  changes, 
atmospheric  oxidation,  or  other  causes,  but  where  most  of  the 
mucilage,  &c.,  originally  present  has  been  already  removed.  In 
such  cases  thorough  agitation  with  a  weak  solution  of  caustic 


ALKALINE   PROCESSES — FOOTS.  261 

soda,  or  a  somewhat  stronger  one  of  sodium  carbonate,  suffices 
to  remove  the  free  fatty  acids  of  low  molecular  weight  (butyric, 
caproic  acids,  &c.)  that  are  present,  as  well  as  others,  if  already 
formed  by  hydrolysis ;  and  to  dissolve  out  most,  if  not  all  of  the 
malodorous  non-acid  products  of  decomposition,  so  as  to  sweeten 
the  oil.  Diluted  milk  of  lime  and  calcined  magnesia  are  some- 
times used  in  a  similar  fashion.  As  a  rule  oils  that  have  once 
become  rancid,  even  if  pretty  thoroughly  'sweetened  by  such 
refining,  are  more  apt  to  turn  rancid  again  on  keeping  than 
fresh  ones.  In  some  cases  agitation  with  water  alone  without 
alkalies  suffices  to  wash  out  the  objectionable  decomposition 
products  to  a  considerable  extent ;  thus  rank  butter  is  greatly 
sweetened  by  simply  being  thoroughly  worked  about  and  washed 
in  water. 

Cokemut  oil  of  inferior  quality  may  be  greatly  improved  by 
boiling  up  with  about  ^  of  its  weight  of  soda  lye,  specific 
gravity  1  -03,  for  half  an  hour,  skimming  frequently.  Some  4  or 
5  Ibs.  of  salt  per  ton  of  oil  are  then  added,  and  the  boiling  con- 
tinued for  another  half  hour.  Another  equal  quantity  of  salt  is 
then  added,  and  the  whole  boiled  up  :  after  standing  till  next 
day  the  cleansed  oil  is  run  off  from  the  brine  and  foots  that  have 
subsided. 

Crude  spermaceti  is  generally  refined  by  processes  partly 
involving  the  mechanical  expression  of  fluid  oil,  somewhat 
after  the  fashion  of  stearine  pressing  (p.  229),  and  partly 
of  a  chemical  nature,  more  especially  boiling  up  with  a  small 
quantity  of  potash  ley ;  this  dissolves  out  free  fatty  acid  formed 
by  the  hydrolysis  of  the  cetin  or  otherwise,  and  saponifies  most 
of  the  residual  fluid  oil,  this  being  more  readily  acted  upon  by 
alkalies  than  cetyl  palmitate  itself.  Simultaneously,  however, 
some  of  the  latter  becomes  saponified,  and  in  consequence  the 
foots  contain  more  or  less  considerable  amounts  of  potassium 
palmitate,  etc.,  whilst  the  purified  spermaceti  contains  an  ad- 
mixture of  cetylic  alcohol  (p.  171). 

Utilisation  of  "  Foots." — The  foots  obtained  from  oils  con- 
taining considerable  quantities  of  resinous  matter  (e.g.,  cotton 
seed  oil  foots)  are  sometimes  directly  worked  up  into  soap  by 
admixture  with  other  materials  in  the  soap  boiling  process. 
When  their  colour  or  nature  prevents  this  being  done,  they  are 
generally  acidified  so  as  to  decompose  the  soaps  present;  the 
mixture  of  fatty  and  resinous  acids  and  more  or  less  unde- 
composed  glycerides  thus  obtained  is  usually  distilled  by  means 
of  superheated  steam,  whereby  the  glycerides  present  are  hydro- 
lysed;  the  fatty  acids  distil  over,  whilst  the  resinous  matters 
mostly  remain  behind  as  a  pitchy  mass.  To  some  extent,  how- 
ever, the  materials  are  generally  broken  up  by  the  heat  with  the 
formation  of  high-boiling  hydrocarbons  and  water,  the  former  of 
which  partly  distil  with  the  fatty  acids ;  the  result  of  which  is 


262  OILS,    FATS,    WAXES,    ETC. 

that  "distilled  oleines"  obtained  from  products  of  this  kind 
(p.  110)  will  not  wholly  dissolve  in  alkaline  solutions  to  soaps, 
the  hydrocarbons  remaining  undissolved.  On  agitating  the 
liquid  with  an  appropriate  volatile  solvent  (ether,  benzoline,  <fec.) 
a  quantity  of  unsaponifiable  matter  can  usually  be  dissolved  out 
from  the  soap  solution  to  the  amount  of  several  per  cents,  of  the 
distilled  oleine  employed.  The  same  remarks  apply  a  fortiori 
to  the  analogous  products  obtained  when  "Yorkshire  grease" 
(Chap,  xii.),  woolgrease,  and  similar  materials  are  distilled  by 
means  of  superheated  steam. 

The  appliances  used  for  such  distillation  with  superheated 
steam  essentially  consist  of  a  boiler  for  steam  raising ;  a  super- 
heater whereby  the  steam  is  heated  considerably  above  the 
temperature  of  the  boiler,  generally  consisting  of  a  coil  of  iron 
tubing  heated  in  a  flue  or  some  analogous  arrangement;  a 
distilling  vessel  into  which  the  material  to  be  distilled  is  run,  the 
steam  being  then  blown  through  it  in  numerous  fine  streams  by 
means  of  a  rose  jet  at  the  bottom,  or  a  coil  perforated  with  small 
holes  ;  and  a  condensing  apparatus  in  which  the  evolved  vapours 
and  the  steam  are  condensed.  In  Chap.  xvi.  are  described  the 
arrangements  employed  in  the  candle  material  manufacture  for 
the  distillation  of  fatty  acids  and  glycerol  by  means  of  super- 
heated steam  ;  those  used  for  the  distillation  of  foots,  recovered 
greases,  &c.,  do  not  greatly  differ  therefrom. 

It  often  happens  that  the  solidity  of  a  grease,  ifec.,  is  greatly 
increased  by  the  process  of  distillation  with  superheated  steam, 
so  that  a  comparatively  soft  grease  after  distillation  gives  a 
product  of  much  stiffer  consistence,  and  capable  of  yielding 
a  considerable  amount  of  solid  "stearine"  by  pressure.  The 
cause  of  this  is  not  absolutely  certain  ;  but  it  is  extremelv 
probable  that  it  is  due  to  the  conversion  of  oleic  acid  into 
isomerides  of  higher  melting  point,  isoleic  acid,  or  stearolactone, 
or  both  (p.  30) ;  just  as  these  products  are  formed  by  the  action 
of  zinc  chloride  on  oleic  acid  (p.  142),  or  during  the  decomposition 
of  glycerides  by  sulphuric  acid  and  their  subsequent  distillation 
with  superheated  steam  in  the  "Wilson"  process  for  obtaining 
candle  material  (Chap,  xvi.) 

Precipitation  Processes. — In  some  few  cases  mucilaginous 
or  albuminous  matters  are  contained  in  oils  and  fats  not  readily 
removable  by  mechanical  means  alone,  such  as  subsidence  or 
filtration,  but  readily  coagulable  by  means  of  certain  metallic 
compounds  or  substances  containing  tannin.  Thus  in  "  boiling  " 
linseed  oil  to  improve  its  drying  qualities  (Chap,  xiv.)  sulphate  of 
zinc,  acetate  of  lead,  sulphate  of  manganese,  and  other  metallic 
salts  are  sometimes  used  not  only  for  the  purpose  of  facilitating 
the  incipient  oxidation  and  physical  alteration  required  to 
make  the  oil  dry  to  a  varnish  more  rapidly,  but  also  in  order 
to  combine  with,  and  remove  by  subsidence,  the  last  portions  of 


BLEACHING    OILS    AND    FATS.  263 

vegetable  mucilage,  &c.,  not  entirely  removed  by  previous  refining 
operations.  Some  kinds  of  fish  oils  are  similarly  improved  by 
vigorous  agitation  with  oakbark  infusion  or  other  liquors  con- 
taining tannin,  conveniently  effected  by  blowing  a  rapid  current 
of  steam  through  the  whole  :  gelatin  is  thus  precipitated  and 
removed  by  deposition  on  standing,  any  excess  of  tannin  taken 
up  by  the  oil  being  subsequently  removed  by  agitation  with  lead 
solution  or  other  appropriate  metallic  salt.  Copper  sulphate 
solution,  alone  or  mixed  with  brine,  when  thoroughly  inter- 
mixed with  fish  oils,  may  often  be  used  effectively  for  removing 
gelatin,  etc.,  therefrom  by  precipitating  it  as  an  insoluble  com- 
pound. 

H.  Nordlinger  has  recently  patented  *  a  process  for  refining 
vegetable  oils  and  precipitating  mucilaginous  matter  consisting 
of  the  preparation  of  "purification-oils"  by  dissolving  in  from 

10  to  20  parts  of  oil  the  zinc,  cadmium,  iron,  manganese,  lead  or 
copper   salts  of  the   higher   fatty  aciols  (metallic   soaps),   at   a 
temperature  of  about  150°  C.,   and  allowing  to   clarify  by  sub- 
sidence.    From  5  to  10  per  cent,  of  the  metallic  soap  solution 
thus  prepared  is  then  added  to  the  oil  to  be  treated  and  the 
whole  allowed  to  stand  some  time,  when  precipitates  are  formed 
by  the  interaction  on  one  another  of  the  mucilaginous  matter 
and  the  metallic  compounds ;  the  clear  supernatant  purified  oil 
is  drawn  off  when  the  action  is  complete. 

Hartley  and  Blenkinsop  have  patented  (No.  11629,  1890)  the 
use  for  refining  linseed  oil  of  a  solution  of  manganese  linoleate  in 

011  of  turpentine  or  other  suitable  solvent :   1  part  of  manganese 
salt  to  800  of  oil  suffices.     If  much  mucilage  is  present  the  oil 
is  previously  treated  with  sulphuric  acid  of  30  per  cent.     By 
blowing  a  current  of  air  or  oxygen  through  the  mass  at  a  tem- 
perature of  about  190°  F.  (88°  C.),  bleaching  is  readily  effected, 
the  manganese  salt  acting  as  a  carrier  of  oxygen. 

BLEACHING  OILS  AND  FATS. 

The  colours  exhibited  by  certain  oils  and  fats,  as  obtained  from 
their  respective  sources,  are  in  general  due  to  the  presence  of 
natural  organic  colouring  matters  (xanthophyll,  erythrophyll, 
chlorophyll,  &c.)  in  solution  in  the  oil ;  in  some  cases  these  are 
mostly  mechanically  carried  down  by  the  mucilaginous  matter 
present  during  clarification  by  subsidence,  &c.,  more  especially 
when  heat  is  also  applied  to  promote  the  coagulation  of  albu- 
minous impurities,  and  particularly  when  oakbark  or  other 
sources  of  tannin  are  employed  as  precipitants  of  these  bodies ; 
in  some  instances  albumin  or  gelatin  is  purposely  added  along 
with  tannin,  to  precipitate  the  colour.  Some  colouring  matters 
are  removable  by  treatment  with  animal  charcoal  and  filtration 

*  German  Patent,  No.  58959. 


264  OILS,    FATS,    WAXES,    ETC. 

somewhat  after  the  fashion  of  sugar  refining  ;  exposure  to  a 
moderately  high  temperature  destroys  others ;  whilst  in  yet 
other  cases  chemical  bleaching  agents  are  requisite,  such  as 
oxidation  by  the  action  of  air  blown  through  the  heated  oil, 
either  alone  or  in  presence  of  oxygen  carriers  ;  or  chlorination 
by  means  of  small  quantities  of  bleaching  powder  or  chlorate 
along  with  hydrochloric  acid ;  or  both  together  by  means  of 
potassium  dichromate  and  dilute  hydrochloric  acid.  With  high 
priced  substances  such  as  beeswax,  bleaching  by  exposure  to  air 
and  light  in  thin  cakes  or  ribbons,  and  in  some  cases  treatment 
with  nitric  acid  or  peroxide  of  hydrogen,  is  applicable,  although 
the  cost  of  labour  and  chemicals  is  prohibitive  of  such  methods 
in  the  case  of  the  cheaper  oils,  £c.  On  the  other  hand,  reducing 
agents,  such  as  ferrous  sulphate  or  sulphurous  acid,  answer  better 
than  oxidising  ones  with  some  kinds  of  oils — e.g.,  linseed  oil. 

Hot  Air  Process. — Certain  fats,  especially  tallow  and  palm 
butter,  can  be  pretty  thoroughly  decolorised  by  heating  them 
and  passing  a  current  of  air  through  the  dry  mass  (containing  no 
interspersed  water)  by  means  of  a  large  rose  with  fine  orifices,  so 
that  many  fine  streams  of  air  bubbles  rise  through  the  hot  fat. 
A  temperature  somewhat  short  of  that  of  boiling  wrater  generally 
suffices  (80°  to  90°  C.)  In  the  case  of  palm  oil  a  somewhat 
higher  temperature,  125°  to  130°  C.,*  also  effects  the  destruction 
of  the  colouring  matter  in  the  absence  of  air ;  a  considerable 
amount  of  the  glyceride  is  thereby  decomposed  with  evolution  of 
acrolein,  and  formation  of  free  palmitic  acid.  Many  fish  oils  are 
greatly  lightened  in  colour  by  blowing  air  through  the  mass, 
heated  to  near  100°  in  a  steam  jacketted  vessel ;  in  these  cases 
the  oil  itself  generally  becomes  more  or  less  oxidised,  increasing 
in  density  and  viscidity,  especially  if  the  air-treatment  be 
carried  too  far  (vide  "blown  oils,"  Chap,  xiv.)  In.  Hartley  and 
Blinkinsop's  process  for  refining  linseed  oil  (supra),  the  oxidising 
action  of  the  air  is  intensified  by  adding  a  manganese  soap 
which  acts  as  a  carrier  of  oxygen. 

Instead  of  blowing  a  stream  of  air  through  the  oil  to  be  treated, 
Teal  f  exposes  rapeseed  or  linseed  oil,  &c.,  in  a  finely  divided 
stream  to  air  at  a  temperature  of  about  170°  F.  (71°  C.),  in  order 
to  "  brighten  "  the  oil. 

W.  Mills  I  bleaches  and  purifies  nondrying  oils  and  fats  by 
means  of  a  mixture  of  hot  air  and  volatilised  sulphur  trioxide, 
S03,  passed  into  a  "  mixer  "  capable  of  withstanding  a  pressure 
of  2  atmospheres.  The  sulphur  trioxide  acts  as  an  oxidising 
agent,  becoming  reduced  to  sulphur  dioxide,  which  also  is 
effective,  especially  whilst  nascent. 

*  240°  C. ,  according  to  Pohl,  who  first  introduced  the  process.  Dingier 
Polyt.  Journ.,  cxxxv.,  140. 

+  Eng.  Patent  Spec.,  18,744,  1892. 
I  Eng.  Patent  Spec.,  18,224,  181)1. 


BICHROMATE    PROCESS.  265 

Bichromate  Processes. — Tn  the  bleaching  of  raw  palm  oil 
by  Watts'  bichromate  process,  the  oil  is  rendered  quite  fluid  by 
heating  it  to  40°  to  50°  C.,  and  is  intermixed  with  1  to  1-25  per 
cent,  of  its  weight  of  potassium  dichromate  dissolved  in  hot 
water  (22  to  28  Ibs.  per  ton).  Strong  hydrochloric  acid  solution 
to  the  extent  of  2  to  2 -5  per  cent,  of  the  oil  is  then  run  in  with 
vigorous  agitation,  enough  being  used  to  ensure  that  a  slight 
excess  of  free  acid  shall  finally  be  present  in  addition  to  that 
neutralised  by  the  chromium  and  potassium.  The  reddish  orange 
hue  changes  rapidly,  first  to  a  dark  brown,  then  to  a  brownish 
green,  and  finally  to  a  light  green,  the  operation  taking  only  a 
few  minutes.  The  whole  is  then  heated  up  by  blowing  wet 
steam  through,  and  allowed  to  stand  at  rest  for  some  hours ;  the 
supernatant  bleached  oil  is  drawn  off  and  used  directly  for 
soapmaking,  &c.,  or  is  washed  by  agitation  with  hot  water,  and 
standing  to  remove  traces  of  chrome  liquor.  The  "  green  liquor  " 
resulting  from  the  operation  is  sometimes  worked  up  to  recover 
the  chrome  by  adding  milk  of  lime  so  as  to  form  a  precipitate  of 
chromium  hydrate  mixed  with  lime ;  this  is  washed  and  drained, 
and  then  roasted,  whereby  oxygen  is  taken  up  and  calcium 
chromate  formed,  used  for  a  fresh  batch  instead  of  potassium 
dichromate.  When  there  are  difficulties  as  to  running  waste 
chrome  liquors  away  into  water  courses,  £c.,  this  method  of 
regeneration  is  practically  imperative ;  but  unless  a  proper 
amount  of  scientific  skill  and  supervision  is  exercised  (not  always 
available  in  a  soapery),  the  cost  of  labour  and  fuel,  ttc.,  is  apt  to 
materially  outweigh  the  value  of  the  potassium  dichromate  saved, 
except  when  the  price  of  this  salt  is  unusually  high. 

Instead  of  hydrochloric  acid,  a  mixture  of  two  parts  sulphuric 
acid  and  three  common  salt  may  be  employed,  the  latter  being 
dissolved  along  with  the  dichromate,  and  the  former  gradually 
run  in  to  the  mass  after  having  been  diluted  with  about  twice 
its  bulk  of  water.  If  the  temperature  be  too  high,  the  bleach- 
ing is  not  always  successful,  a  brownish  "  foxy "  shade  being 
developed ;  about  45°  to  50°  C.  may  be  taken  as  a  working 
maximum  ;  the  proportion  of  dichromate  used  need  not  exceed 
28  Ib.  to  the  ton  (J^  part  =  1'25  per  cent.)  in  skilled  hands. 

A  similar  mode  of  treatment  is  available  with  many  other  oils, 
the  use  of  hydrochloric  acid  to  generate  nascent  chlorine  not 
being  necessary  in  all  cases  ;  thus  with  various  fish  oils  a  few 
pounds  of  dichromate  to  the  ton,  with  about  half  as  much 
sulphuric  acid,  answer  best,  the  oxidation  being  completed  by 
adding  a  small  proportion  of  nitric  acid  largely  diluted,  and 
boiling  up  with  steam.  In  other  instances,  treatment  with 
dichromate  improves  the  product,  not  so  much  by  simply  bleach- 
ing as  by  oxidising  and  removing  the  small  quantities  of  malo- 
dorous substances  present  that  communicate  a  foetid  or  rancid 
odour — e.g.,  kitchen  grease,  horse  grease,  &c. 


266  OILS,    FATS,    WAXES,  ETC. 

Beeswax  is  frequently  bleached  by  boiling  with  a  weak  solu- 
tion of  potassium  dichromate,  acidulated  with  sulphuric  acid. 
The  product  is  apt  to  retain  chromium  compounds,  giving  it  a 
greenish  hue  ;  boiling  up  with  oxalic  acid  solution  appears  to  be 
the  best  mode  of  dissolving  out  the  chrome  and  furnishing  a 
white  product.  Instead  of  "  chromic  liquor,"  dilute  nitric  acid 
is  sometimes  employed,  taking  care  not  to  use  too  much  or  of 
too  great  strength,  otherwise  more  or  less  considerable  loss  is 
apt  to  occur  through  oxidation  of  the  wax  itself. 

Wax  thus  bleached  by  oxidising  chemicals  is  generally  more 
•crystalline  than  air  bleached  wax,  and  consequently  not  so 
well  suited  for  the  manufacture  of  wax  candles.  According  to 
Leopold  Field, *  whilst  the  solubility  in  alcohol  of  air  bleached 
\vax  differs  but  little  from  that  of  the  raw  wax,  that  of 
-chemically  bleached  wax  is  much  greater,  leading  to  the  idea 
that  free  fatty  acids  are  largely  formed  during  the  bleaching 
process,  giving  greater  crystallimty. 

Instead  of  potassium  dichromate,  manganese  dioxide  has  been 
employed  for  bleaching  oils,  especially  palm  oil ;  the  powdered 
substance  suspended  in  water  is  intermixed  with  the  oil  by 
vigorous  agitation,  and  hydrochloric  acid  added  so  as  to  generate 
chlorine,  whilst  the  whole  is  heated  by  blowing  in  steam.  The 
only  advantage  of  the  process  seems  to  be  the  lessened  cost, 
against  which  several  other  inconveniences  must  be  set  off,  the 
action  being  far  less  regular.  The  same  remark  applies  to  the 
process  formerly  used  to  some  extent  where  manganese  dioxide 
and  sulphuric  acid  were  employed. 

Chlorine  Processes. — Chlorine  evolved  from  substances  other 
than  potassium  dichromate  and  hydrochloric  acid  is  sometimes 
-employed  as  a  bleaching  agent ;  thus  tallow  may  be  bleached  by 
boiling  it  on  a  solution  of  bleaching  powder  or  potassium  chlorate 
to  which  hydrochloric  or  sulphuric  acid  is  added;  about  2  to  2 '5 
Ibs.  of  chlorate  per  ton  usually  suffices.  In  all  such  processes, 
when  the  fat  is  intended  for  soapmaking,  excess  of  chlorine  is 
apt  to  produce  a  worse  result  than  none  at  all  so  far  as  colour 
is  concerned  (leaving  deodorising  out  of  the  question)  ;  for  if  the 
fatty  glycerides  themselves  are  sensibly  attacked  by  the  chlorine 
after  the  colouring  matters  have  been  destroyed,  the  resulting 
soap  is  apt  to  "  work  foxy  "• — i.e.,  either  to  become  brown  in  the 
pan  during  boiling,  or  to  darken  in  colour  subsequently  when 
cut  up  into  bars.  On  the  other  hand,  the  unpleasant  odour  of 
rancid  tallow  and  grease  from  tainted  or  putrid  carcases,  tannery 
refuse,  and  suchlike  materials  is  apt  to  be  communicated  in  some 
degree  to  the  resulting  soap  unless  the  grease  is  previously 
deodorised  by  chlorine,  etc.  In  many  cases  a  great  improvement 
in  odour  may  be  brought  about  by  simply  blowing  steam  through 

*  Journ.  Soc.  Arts,  xxxi.,  p.  836. 


CHLORINE    PROCESSES.  267 

the  melted  grease  for  some  time,  the  volatile  evil-scented  matters 
present  being  thus  largely  expelled. 

With  rank  fish  oils  larger  proportions  of  bleaching  powder  are 
requisite  up  to  1  per  cent,  and  upwards,  with  an  equivalent 
quantity  of  sulphuric  acid ;  the  bleaching  powder  is  made  into 
a  milk  with  water  and  well  intermixed  with  the  oil,  which  is 
slightly  heated  by  blowing  in  a  little  steam  ;  the  acid  diluted 
w^ith  several  times  its  volume  of  water  is  then  run  in  with 
vigorous  agitation.  Finally,  steam  is  blown  through  and  the 
whole  allowed  to  rest  and  subside. 

Chlorine  bleaches  wax  readily,  but  chlorosubstitution  products 
are  apt  to  be  formed,  so  that  if  the  bleached  wax  is  used  for 
making  tapers  or  candles,  hydrochloric  acid  vapours  are  evolved 
when  these  are  burnt,  causing  considerable  annoyance.* 

Cotton  seed  oil  in  the  raw  state  contains  a  peculiar  colouring 
matter  capable  of  being  dissolved  out  along  with  resinous  matters 
by  agitation  with  aqueous  solutions  of  caustic  alkalies  (p.  260). 
Sometimes  this  purification  is  only  partly  carried  out,  the 
residual  colouring  matter  being  destroyed  by  boiling  with  a  dilute 
solution  of  bleaching  powder  and  treatment  with  dilute  sul- 
phuric acid.  The  oils  thus  more  or  less  completely  refined  and 
decolorised  by  chemicals  are,  as  a  rule,  only  used  for  soapmaking 
and  similar  technical  purposes ;  whereas  those  completely  refined 
by  soda  alone  are  used  as  edible  oils,  being  largely  used  for 
cooking  purposes,  and  to  a  great  extent  intermixed  with  olive 
and  other  high-priced  "salad"  oils.  As  a  rule  each  oil  refiner- 
has  his  own  particular  special  methods  of  effecting  the  final 
clarification  and  finish  of  such  superior  products,  which  are  looked 
upon  as  valuable  trade  secrets. 

Dark  coloured  soaps  are  sometimes  bleached  more  or  less  com- 
pletely by  intermixing  with  the  hot  curd  freed  from  ley,  a  solution 
of  "  chloride  of  soda  "  (bleaching  powder  made  into  a  cream  and 
treated  with  enough  carbonate  or  silicate  of  soda  to  remove  all 
lime  from  solution).  This  may  be  effected  in  the  pan  itself,  but 
is  best  done  by  crutching  the  liquid  into  the  soap  in  the  frame 
(A.  Watt):  the  precipitated  carbonate  or  silicate  of  lime  need 
not  be  previously  removed.  If  made  from  coarse  rank  "  goods," 
the  soap  will  be  largely  deodorised  by  the  process. 

Peroxide  of  Hydrogen  Process. — The  bleaching  action  of 
peroxide  of  hydrogen  on  certain  forms  of  organic  colouring 
matters  has  long  been  known  and  utilised  in  certain  cases  where 
the  cost  was  not  prohibitive — e.g.,  in  the  manufacture  of  various 

*The  important  chemical  discovery  that  "electropositive"  hydrogen 
could  be  replaced  in  organic  compounds  by  highly  "electronegative"  chlorine 
without  materially  altering  the  character  of  the  substance  affected  was  first 
made  in  consequence  of  investigations  carried  out  by  Gay  Lussac  in  order 
to  elucidate  the  cause  of  this  occurrence  in  the  reception  rooms  of  the 
Emperor  Napoleon  I.,  where  wax  candles  were  largely  burnt. 


268  OILS,    FATS,    WAXES,    ETC. 

high-priced  toilet  fluids  for  converting  dark  hair  into  substances 
of  golden  hue,  or  even  bleaching  completely  white.  Notwith- 
standing improvements  whereby  the  cost  of  manufacture  of  per- 
oxide of  hydrogen  is  greatly  reduced,  this  substance  is  still  too 
expensive  for  use  on  the  large  scale  for  low-priced  oils,  &c., 
although  in  many  cases  it  is  well  fitted  for  the  purpose.  Drying 
oils  required  for  artists'  varnishes  are  sometimes  bleached  by 
floating  them  in  a  thin  layer  on  the  surface  of  hydrogen  peroxide 
dissolved  in  water,  the  whole  being  warmed  and  if  possible 
exposed  to  sunlight  to  facilitate  the  operation.  By  shaking  up 
repeatedly  in  a  closed  vessel  Avith  about  ^  part  of  a  10  per  cent, 
solution  of  peroxide  of  hydrogen  most  oils  can  be  rapidly 
bleached,  or  at  least  greatly  lightened  in  colour. 

Wax  Bleaching  by  Exposure  to  Air.— The  effect  of  light 
and  air  011  beeswax  in  removing  the  natural  yellowish  tinge  is 
utilised  thus  :  The  wax  is  first  melted  and  boiled  up  with  water 
acidulated  with  a  small  quantity  of  sulphuric  acid  (about  1  part 
by  weight  of  oil  of  vitriol  per  1000  of  wax);  impurities  are  thus 
washed  out,  and  a  clear  bright  melted  wax  obtained.  This  is 
then  run  from  a  sort  of  cullender  pierced  with  holes  on  to  a 
drum  half  immersed  in  a  tank  of  cold  water ;  as  the  streams  of 
fluid  wax  come  in  contact  with  the  cool  wet  surface  they  solidify 
into  thin  ribbons  which  are  scraped  off  the  drum  after  they  have 
passed  down  under  the  water  so  as  to  complete  their  solidification. 
.Filially,  the  ribbons  are  spread  out  in  thin  layers  on  canvas 
sheeting,  and  placed  in  the  open  air  so  as  to  be  exposed  to  the 
sun  and  air.  After  a  time,  the  partially  bleached  ribbons  are 
remelted  and  again  cast  into  ribbons,  and  exposed  for  a  further 
period,  the  whole  operation  lasting  several  weeks  according  to  the 
weather  and  the  nature  of  the  wax,  some  kinds  yielding  much 
more  rapidly  to  atmospheric  oxidation  than  others.  Usually 
only  the  outer  portions  of  the  ribbons  become  bleached,  the  action 
not  penetrating  far  into  the  interior  ;  so  that  to  expose  the  whole 
equally  to  light  and  moisture,  the  mass  requires  to  be  turned 
over  from  time  to  time  and  sprinkled  with  water ;  obviously  the 
thinner  the  ribbons  are,  the  better. 

In  the  purification  of  Japanese  wax  a  very  similar  process 
is  adopted  ;  the  crude  wax  as  obtained  from  the  dried  berries 
of  the  Rhus  succedanea,  is  melted  and  strained,  dripping  into 
water  kept  agitated  so  that  it  solidifies  in  thin  flakes  ;  these 
are  then  exposed  to  sun  and  air  in  trays,  being  now  and  then 
sprinkled  with  water  and  turned  over ;  the  vegetable  colouring 
matter  present  in  the  crude  wax  is  thus  readily  blanched,  an 
almost  white  product  being  obtained.  In  the  case  of  some 
varieties  of  beeswax  this  result  cannot  be  so  readily  secured,  the 
colour  sometimes  not  yielding  at  all  readily  to  atmospheric 
influences.  Addition  of  a  small  quantity  of  fatty  matter  to 
beeswax  often  facilitates  the  bleaching  action  of  the  atmosphere 


WAX    BLEACHING. 


269 


under  the  influence  of  sunlight ;  according  to  some  authorities 
the  quality  of  the  wax  is  not  improved  thereby,  whilst  the 
presence  of  glycerides  is  usually  regarded  as  proof  of  adulter- 
ation ;  on  the  other  hand,  A.  &  P.  Buisine  (infra]  state  that 
the  addition  of  3  to  5  per  cent,  of  tallow  is  universal  amongst 
French  airbleachers  in  order  to  prevent  the  product  becoming 
brittle,  and  is  not  regarded  at  all  as  an  adulteration.  A  small 
percentage  of  oil  of  turpentine  is  sometimes  used  instead  of  fatty 
matter ;  the  volatile  hydrocarbon  mostly  escapes  during  the 
process  by  exposure  to  air ;  but  a  small  quantity  becomes 
resinised  by  oxidation  and  retained  by  the  wax ;  probably  this 
oxidation  gives  rise  to  peroxide  of  hydrogen  in  minute  quantity 
which  assists  the  bleaching  action. 

According  to  A.  &  P.  Buisine  *  the  chemical  bleaching  of 
beeswax  is  always  accompanied  by  an  increase  in  the  total 
acid  number,  and  a  diminution  in  the  iodine  number,  indicating 
the  direct  addition  of  oxygen  to  the  uiisaturated  acids  present; 
thus  the  following  figures  wrere  obtained  in  a  long  series  of 
experiments  : — 


Iodine  absorbed 
by  100  parts  of  wax. 

Total  acid 
number. 

Pure  yellow  waxes,          .... 
Pure  airbleached  waxes, 

10  -87  to  11-23 
6  to  7 

91  to  95 
93  to  100 

Airbleached,  with  addition  of  3  to  5  per 
cent,  of  tallow,    ..... 

6  to  7 

105  to  115 

Airbleached  with  addition  of  5  per  cent, 
spirit  of  turpentine,     .... 
Bleached  by  hydrogen  dioxide, 
Decolorised  by  permanganate, 
Decolorised  by  bichromate,     . 

6-78 
6'26 
2-64  to  5-80 
1-08  to  7-94 

100-4 
98-4 
92-2  to  103-3 
98  -9  to  107  '7 

On  the  other  hand,  decolorisation  "by  means  of  animal  char- 
coal caused  no  marked  alteration  in  either  the  total  acid  number 
or  the  iodine  absorption. 

An  indirect  method  of  bleaching  by  means  of  air  is  sometimes 
practised,  especially  with  linseed  oil;  the  oil  to  be  treated  is 
agitated  at  intervals  with  ferrous  sulphate  solution  ;  this  has  a 
tendency  to  peroxidise  by  absorption  of  oxygen  from  the  air, 
whilst  the  resulting  ferric  compound  parts  with  oxygen  to  the 
colouring  matter,  oxidising  the  latter  and  blanching  it,  whilst 
becoming  itself  again  reduced  to  the  ferrous  state ;  and  so  on 
continuously. 

*  Bulletin  Soc.  Chim.,  Paris,  1890,  iv.,  p.  465. 


270  OILS,    FATS,    WAXES,    ETC. 


CHAPTER    XII. 
RECOVERY  OF  GREASE  FROM  "SUDS,"  &c. 

IN  certain  textile  industries,  more  especially  the  woollen  manufac- 
ture, and  to  a  somewhat  lesser  extent  the  silk  and  cotton 
industries,  the  materials  are  treated  at  particular  stages  of  the 
process  with  soap  liquors  for  the  purpose  of  washing  out  impuri- 
ties of  various  kinds  ;  whilst  in  various  dyeing  operations  soaping 
is  also  resorted  to  for  the  purpose  of  clearing  off  superfluous 
dyestuff,  cleansing  the  undyed  portions,  and  so  on.  Formerly, 
the  "  soap  suds  "  thus  produced  were  thrown  away  by  running 
into  the  nearest  available  stream,  &c.;  but  the  great  amount  of 
river  pollution  thus  brought  about  has  in  many  cases  rendered 
it  imperative  that  at  least  some  amount  of  purification  of  such 
liquors  should  be  effected  before  they  are  thus  run  away ; 
whilst  the  value  of  the  fatty  matters  saved  by  adopting  proper 
processes  for  such  purification,  often  renders  it  profitable  to 
employ  such  methods,  even  when  so  doing  is  not  otherwise 
compulsory. 

The  methods  adopted  necessarily  vary  to  some  extent  with  the 
nature  of  the  materials  to  be  dealt  with  ;  in  cases  where  coloured 
waste  liquors  from  dyeworks,  (fee.,  constitute  the  great  bulk  of 
the  substance  to  be  treated,  the  cheapest  and  most  satisfactory 
methods  appear  to  be  modifications  of  the  precipitation  processes 
employed  in  similarly  dealing  with  sewage ;  thus  by  adding  a 
small  proportion  of  milk  of  lime  to  the  liquors,  and  simultane- 
ously running  in  a  solution  of  crude  aluminium  sulphate,*  the 
alumina  and  ferric  oxide  precipitated  by  the  lime  unite  with  the 
colouring  matters  forming  "  lakes,"  which  ultimately  subside  by 
gravitation  in  suitable  settling  tanks,  carrying  down  mechanically 
with  them  various  other  impurities  (albuminoid  matters,  fatty 
acids,  &c.),  so  as  finally  to  yield  a  clear  almost  colourless  effluent 
containing  in  solution  only  non-precipitable  matters  such  as 
alkaline  salts,  (fee.  The  "  sludge  "  thus  resulting  is  usually  of  but 
little  value,  even  for  manure.  When,  however,  soap  suds  con- 
stitute a  sufficiently  large  proportion  of  the  waste  liquors,  it  is 
preferable  to  collect  and  treat  these  separately  so  as  to  recover 

*  Aluminoferric  cake  containing  somewhat  large  amounts  of  iron,, 
chiefly  obtained  from  the  mother  liquors  of  purer  aluminium  sulphate  made 
by  treating  bauxite,  clay,  &c. ,  with  sulphuric  acid. 


YORKSHIRE    GREASE.  271 

the  grease,  the  slightly  acid  watery  liquors  left  after  this  opera- 
tion being  either  run  away  directly,  or,  preferably,  admixed 
with  the  coloured  waste  liquors,  and  the  whole  treated  together 
as  above  described ;  a  little  more  lime  is  requisite  in  this  case 
to  neutralise  the  free  acid  contained  in  the  grease  recovery 
liquors,  which  must  be  done  before  the  alumina  can  be  effectively 
precipitated  from  the  sulphate.  The  precise  details  of  the 
method  of  working  necessarily  vary  in  each  instance ;  but  it  is 
within  the  author's  knowledge  that  processes  substantially  of  the 
character  described  can  be  so  worked  as  to  answer  the  purpose  in 
most  satisfactory  fashion,  especially  when  carefully  carried  out 
under  pressure  of  an  impending  injunction. 

Two  methods  of  treating  soap  suds  are  thus  applicable ;  in  one 
the  soap  is  made  to  react  upon  a  lime  compound  such  as  thin  milk 
of  lime  or  solution  of  calcium  chloride  so  as  to  form  insoluble  lime 
soaps  by  double  decomposition;  these  are  collected  by  subsidence 
and  nitration  (the  more  or  less  purified  liquor  being  run  away), 
and  subsequently  decomposed  by  sulphuric  or  hydrochloric  acid 
so  as  to  liberate  the  fatty  acids,  thus  obtaining  a  more  or  less, 
impure  grease ;  after  hot  pressing  or  filtration  the  fatty  acids 
are  obtained  separate  from  the  solid  matters  admixed  with 
them,  and  may  be  utilised  in  the  production  of  rough  soap,  cart 
grease,  &c.,  or  submitted  to  distillation  with  superheated  steam, 
according  to  their  nature  and  degree  of  impurity.  This  lime 
process  is  more  especially  applicable  to  comparatively  dilute 
suds,  &c.,  where  the  object  is  rather  to  get  rid  in  some  way  or 
other  of  a  dirty  waste  liquor  which,  from  the  circumstances  of  the 
case,  must  be  somewhat  purified  before  discharging,  than  to  work 
a  recovery  process  profitable  in  itself.  When,  however,  the  soap 
liquors  are  more  concentrated,  the  other  method  is  preferable, 
consisting  of  simple  acidulation  of  the  suds  with  sulphuric  *  or 
hydrochloric  acid  ;  the  fatty  acids  thus  liberated  would  naturally 
float  up  as  a  sort  of  greasy  scum,  were  it  not  for  the  presence  of 
other  heavier  suspended  matters  which,  in  most  cases,  and  more 
especially  with  wool  scouring  soap  suds,  render  the  total  preci- 
pitate ("magma"  or  "coagulate")  somewhat  heavier  than  the 
watery  fluid,  causing  it  to  sink.  This  process  is  more  especially 
employed  in  the  recovery  of  "  Wakefield  fat"  or  "Yorkshire 
grease,"  which  essentially  consists  not  only  of  free  fatty  acids 
derived  from  soap,  but  also  of  wool  grease  contained  in  the  raw 
wool,  and  other  oleaginous  matters  «used  in  the  spinning  and 
weaving  processes. 

In  the  English  woollen  industry,  the  method  of  cleansing  wool 
usually  adopted  essentially  consists  in  scouring  with  soft  soap,  or 

*  Chamber  acid  suffices,  or  acid  from  the  Glover  tower,  rectified  oil  of 
vitriol  being  too  costly,  except  in  cases  where  the  less  cost  of  carriage  of  the 
smaller  bulk  outweighs  the  increased  price  through  cost  of  further  concen- 
tration. 


272  OILS,    FATS,    WAXES,    ETC. 

other  soaps  of  special  character ;  during  the  further  processes 
through  which  the  wool  is  put  before  it  is  finally  converted 
into  woven  cloth,  soap  and  oil  are  tolerably  freely  used  in  the 
spinning,  fulling,  and  milling  of  the  fibre,  yarn,  and  cloth. 
The  soap  suds  and  similar  waste  liquors  produced  in  these 
various  operations  are  collected  in  large  tanks  or  reservoirs, 
holding  several  thousand  gallons,  and  acidulated  with  a  mineral 
acid — e.g.,  B.O.  V.  (brown  oil  of  vitriol) ;  after  agitation  and 
subsequent  standing  for  some  hours,  a  fatty  "  magma "  or 
coagulate  deposits  at  the  bottom  of  the  tank  ;  the  supernatant 
watery  fluid  (which  should  be  slightly  acid,  otherwise  the  whole 
of  the  soap  has  not  been  decomposed)  is  then  run  off,  and  the 
tank  filled  up  with  fresh  suds  and  acidulated  as  before,  excepting 
that  somewhat  less  acid  is  now  requisite,  owing  to  the  smaller 
quantity  of  suds  treated,  the  tank  having  been  partly  filled  with 
magma  and  watery  fluid  (with  a  tank  6  feet  deep,  the  magma, 
etc.,  usually  fills  up  15  or  18  inches).  The  process  is  again 
repeated,  the  magma  (known  locally  in  Yorkshire  as  "  sake ") 
being  ultimately  thrown  on  filter  beds,  where  most  of  the 
remaining  watery  liquor  separates,  and  then  subjected  to 
pressure  in  bagging ;  at  first  the  pressure  is  very  gently  applied, 
so  as  to  squeeze  out  water  only,  but  subsequently  it  is  increased 
and  heat  applied  (hot  press),  so  as  to  filter  the  fused  mass 
through  the  bagging,  furnishing  a  dark  sticky  grease,  and  a 
residual  "  sudcake  "  available  as  manure.  This  grease  is  what 
is  properly  called  "  Yorkshire  grease  ;"  but  similar  recovered 
products  ("Fuller's  grease")  obtained  by  treating  the  soap  suds 
produced  in  other  industries  where  scouring  with  soap  is  largely 
employed,  are  sometimes  included  in  the  term  (cotton  industry, 
silk  manufacture,  dyeing,  &c.)  Genuine  Yorkshire  grease  from 
wool  scouring  essentially  consists  of  the  free  fatty  acids  derived 
from  the  soap  used,  the  wool  grease  contained  in  the  wool, 
and  such  unsaponified  oil  and  mineral  hydrocarbons,  &c.,  as 
may  have  been  used  in  the  spinning  and  weaving  operations 
for  the  purpose  of  oiling  or  sizing  the  yarn,  &c. ;  whilst 
analogous  greases  from  other  sources  are  more  or  less  different 
as  regards  the  nature  of  the  substances  present  other  than  free 
fatty  acids. 

According  to  Lewkowitsch,*  Yorkshire  grease  rarely,  if  ever, 
contains  unsaponified  glycerides,  any  glyceridic  oils  used  in  the 
spinning  process  becoming  saponified  during  the  after  processes 
of  washing,  tfcc. ;  so  that  the  essential  organic  constituents  are — 
(1)  free  fatty  acids,  partly  derived  from  the  wool  grease,  but 
chiefly  from  the  soaps  used  in  washing ;  (2)  cholesterol  and 
isocholesterol  ethers,  and  similar  derivatives  of  other  high 
alcohols — e.g.,  cetylic  and  cerylic  alcohols ;  (3)  free  alcohols 
(cholesterol,  &c.),  either  naturally  contained  in  wool  grease,  or 
*  Journ.  Soc.  Chem.  Ind.,  1892,  p.  134. 


ANALYSIS    OF    YORKSHIRE    GREASE.  273 

produced  during  scouring  by  the  partial  saponification  of  their 
compound  ethers ;  together  with  hydrocarbons  contained  in  the 
oils  used  for  greasing  during  spinning,  &c. 

Analysis  of  Yorkshire  Grease. — The  free  acids  are  usually 
determined  by  titration  in  the  usual  way  (p.  116),  their  average 
molecular  weight  being  assumed  to  be  some  constant  value — e.g., 
282  =  oleic  acid ;  inasmuch,  however,  as  they  usually  contain  a 
notable  amount  of  acids  of  much  higher  molecular  weight,  derived 
from  the  wool  grease,  this  mode  of  calculation  is  apt  to  give  too 
low  a  result.  In  order  to  obtain  a  more  exact  valuation,  the 
alcoholic  soap  solution  thus  formed  may  be  diluted  with  water, 
and  shaken  with  ether  or  light  petroleum  spirit,  so  as  to  dissolve 
out  all  other  constituents  (or  better,  evaporated  to  dryness  and 
exhausted  with  ether  or,  preferably,  light  petroleum  spirit, 
p.  119,  as  the  ethereal  and  watery  fluids  are  apt  to  form  frothy 
emulsions,  not  readily  separating  into  two  liquids) ;  the  weight  of 
the  free  fatty  acids  insoluble  in  water  is  then  determined  by 
acidulation,  etc.,  as  in  Hehner's  process  (p.  166  );  by  titrating 
these  with  alkali,  and  subtracting  the  amount  neutralised  from 
that  neutralised  during  the  first  titration,  the  alkali  equivalent 
to  the  soluble  acids  may  be  deduced  (p.  168);  so  that  these  latter 
may  be  calculated,  assuming  an  average  molecular  weight — e.g., 
102  =  valeric  acid,  C5H10O2. 

The  sum  of  the  cholesterol  ethers,  &c.,  and  unsaponifiable 
matters  is  obtained  by  weighing  the  ether  or  petroleum  spirit 
extract ;  \vhen  only  an  approximately  exact  result  is  required, 
this  may  be  got  by  difference,  subtracting  the  fatty  acids  found 
by  titration  (together  with  water,  mineral  matters,  &c.)  from  100 
(vide  infra}.  The  cholesterol  ethers  saponify  only  with  great 
difficulty  ;  the  best  mode  of  procedure  is  to  heat  under  pressure 
with  excess  of  double-normal  alcoholic  potash  (in  a  tightly 
closed  vessel  heated  to  100°) :  in  this  way  a  measure  of  the 
amount  of  compound  ethers  present  is  obtained,*  so  that  by 
again  assuming  a  mean  molecular  weight  (e.g.,  that  of  cholesterol 
stearate,  C.>6H43 .  O  .  C18H35O  =  638),  their  amount  may  be  calcu- 
lated. A  preferable  method,  however,  is  to  separate  the  soaps 
thus  formed  as  before  by  means  of  ether,  &c.,  dissolving  out  the 
alcohols  formed  by  saponification  (or  pre-existing  in  the  grease) 
and  hydrocarbons,  <fcc.  ;  the  fatty  acids  contained  in  the  soaps 
are  separated  and  weighed,  and  the  alcohols,  &c.,  obtained  by 
evaporating  off  the  solvent.  The  acetyl  test  (p.  186)  applied  to 
this  residue  allows  an  estimation  to  be  made  of  the  alcoholiform 
constituents,  again  assuming  a  mean  molecular  weight — e.g.,  that 
of  cholesterol,  C.,6H44O  =  372,  whence  the  amount  of  hydrocarbons 
present  is  known  by  difference. 

*If  substances  analogous  to  stearolactone  (p.  170)  are  present,  or  organic 
anhydrides  (possibly  present  in  distilled  grease),  alkali  is  also  neutralised  by 
them  during;  this  operation. 

18 


274  OILS,    FATS,    WAXES,    ETC. 

The  figures  thus  obtained  will  then  come  out  as  follows :  — 
FIRST  TREATMENT. 


A  B 


Free  fatty  acids  insoluble  in  water  (weighed). 
,,       ,,        ,,      soluble  in  water  (calculated 
from  difference  of  titration). 


SECOND  TREATMENT  OF  B. 


Compound  ethers,  alcohols, 
and  hydrocarbons 

(weighed). 


Fatty  acids    contained    in 
compound  ethers 
(weighed). 


D 

Alcohols  (pre-existing  and  formed  by  saponi- 
fication)    and    hydrocarbons    (weighed). 


The  former  calculated  as  CgeH^O  from 
the  acetyl  test  ;  the  latter  by  subtracting 
the  quantity  thus  found  from  D. 


Since  water  is  taken  up  during  the  saponification  of  the  com- 
pound ethers,  the  sum  of  the  organic  constituents  thus  reckoned 
should  exceed  100,  as  in  the  parallel  case  of  soap  when  the  total 
alkali  and  fatty  acids  present  are  determined  (Chap,  xxi.) 

For  certain  purposes,  more  especially  the  preparation  of 
"lanolin"  or  similar  cholesterol  products  of  more  or  less 
purity,  the  proportion  of  alcohols  present  regulates  the  value 
of  the  material  more  than  does  the  amount  of  fatty  acids. 
The  presence  of  hydrocarbons  (whether  intentionally  added  as 
ingredients  in  the  oiling  process  during  spinning,  <fcc.,  or  due  to 
adulteration  of  the  oils  thus  used  with  petroleum  products  or 
rosin  oils,  or  formed  during  distillation  of  grease,  the  "oleine" 
thereby  obtained,  p.  279,  being  used  for  wool-oiling)  considerably 
depreciates  the  value  of  the  material  for  these  purposes:  in 
many  cases  the  presence  of  such  substances  in  the  extract  D 
obtained  as  above  can  be  indicated,  and  the  amounts  roughly 
judged,  by  treating  this  residue  with  alcohol  or  glacial  acetic 
acid,  in  which  solvents  the  hydrocarbons  are  only  sparingly 
soluble. 

For  many  purposes  a  less  troublesome  method  of  analysis 
suffices ;  thus  Lewkowitsch  (loc.  cit.  supra)  recommends  the 
following  process  for  the  examination  of  Yorkshire  grease  : — 
About  5  grammes  are  titrated  with  alcohol  and  seminormal 
alkali  ;  another  portion  is  similarly  titrated  by  boiling  with 
excess  of  alkali  (i.e.,  the  "free  acid  number"  and  the  "total 
acid  numbers"  are  determined);  the  difference  between  these 
titrations  gives  a  measure  of  the  compound  ethers,  glycerides, 
and  other  saponifiable  matters  present.  By  means  of  ether 
(preferably,  light  petroleum  spirit,  p.  119)  the  "  unsaponifiable 


ANALYSIS  OF  YORKSHIRE  GREASE.  £75 

matters"  (alcohols,  hydrocarbons,  £c.)  are  dissolved  out  and 
weighed,  whilst  the  "  insoluble  fatty  acids  "  and  "  volatile  "  acids 
are  determined  by  the  Hehner  and  lleichert-Meissl  processes 
(pp.  166,  174).  Thus  a  sample  of  Yorkshire  grease  yielded  the 
following  results  : — 

Unsapotritiable  matters  (weighed),  .         .         .         .     36*47  per  cent. 

Free  fatty  acids  ;  insoluble  (weighed — Hehner 

number), 20 '22  ,, 

Free  volatile  acids  (calculated  as  CSH10O2),    .         .       1'2S         „ 

Combined  fatty  acids  (calculated  from  difference  of 
titrations,  assuming  the  mean  molecular  weight 
=  327-5), 48-47 


106-44 


The  excess  of  6 '44  per  cent,  thus  found  is  partly  due  to  the 
water  taken  up  during  hydrolysis  of  the  compound  ethers  ;  pro- 
bably also  the  assumed  mean  molecular  weight  of  the  combined 
fatty  acids  (327 '5)  is  somewhat  too  high.  On  the  other  hand  the 
value  282  (oleic  acid)  would  be  too  low. 

In  the  determination  of  the  unsaponifiable  matters  present 
"W.  Mansbridge  *  recommends  in  place  of  ether  the  use  of  light 
petroleum  spirit  (commercial  benzoline  redistilled,  collecting  the 
part  distilling  at  about  110°  F.  =  43°  C.);  the  grease  is  saponified 
with  excess  of  alcoholic  potash  (under  pressure  if  requisite),  and 
the  product  decomposed  with  mineral  acid,  whereby  a  mixture  of 
free  fatty  acids  and  unsaponifiable  matters  is  obtained.  Of  this 
a  portion  sufficient  to  yield  about  O5  gramme  of  unsaponifiable 
matter  is  dissolved  in  50  c.c.  of  methylated  spirit  saturated 
with  benzoline  distillate,  and  50  c.c.  of  that  distillate  added;  the 
whole  is  heated  just  to  boiling,  directly  neutralised  with  semi- 
normal  potash,  and  then  transferred  to  a  separating  funnel, 
where  the  hot  benzoline  solution  of  unsaponifiable  matter,  and 
the  alcoholic  soap  solution,  separate  from  one  another  rapidly. 
The  alcoholic  soap  solution  is  run  off,  and  50  c.c.  of  water  at 
100°  F.  (37°'8C.)  added,  and  the  whole  agitated  to  wash  out  any 
soap  dissolved  by  the  benzoline.  After  separating  by  standing, 
the  watery  fluid  is  run  off,  and  replaced  by  40  c.c.  of  warm  70 
per  cent,  alcohol  :  this  when  agitated  with  the  benzoline  removes 
the  last  traces  of  dissolved  soap.  The  alcoholic  soap  solution 
first  run  off  is  agitated  a  second  time  with  benzoline,  and  the 
benzoline  solution  purified  as  before  :  for  some  kinds  of  grease 
more  than  two  such  extractions  are  requisite,  but  in  general  two 
suffice. 

The  percentage  of  unsaponifiable  matters  (including  choles- 
terol, &c.,  produced  by  decomposition  of  cholesterol  ethers)  thus 
deduced  is  not  far  removed  from,  but  is  usually  somewhat  less 

*  C.'um'x.tl  News,  27th  May,  1892. 


276 


OILS,    FATS,    WAXES,    ETC. 


than,  that  calculated  by  assuming  that  the  fatty  acids  present  (free 
and  combined  as  cholesterol  ethers,  *fcc.)  have  the  mean  molecular 
weight  282  (oleic  acid),  and  subtracting  their  weight  (together 
with  water,  suspended  matters,  &c.)  from  100.  Thus  Mansbridge 


gives  the  following  comparisons  : — 


Pure  woolfat,  .... 

,,  ,,        another  sample, 

West  of  England  recovered  grease, 

West  of  England  recovered  grease, 
another  sample,    .... 

Distilled  woolfat,    .... 

Oleine  from  distilled  woolfat, . 

Oleine  from  distilled  \voolfat, 

another  sample,  .... 

Black  srease  recovered  from  shoddy 
scourings,     ..... 


Unsaponifiable  Matters. 

By  extraction 
as  above. 

By  titration, 

&c. 

{ 

29-05 
29-25 

39-36 

41-70 
41  70 

46-79 

( 

21  -55 

(   23-16 

i 

21-05 

j   23-16 

| 

22-81 

23-63 

1 

52-25 

I   48-64 

1 

51-90 

I   48-64 

r 

44-35 
44-25 

44-31 

{ 

50-25 
50-35 

47-13 

( 

22-61 

°5"55 

1 

22*72 

According  to  A.  Hess  *  the  difference  between  the  amounts  of 
unsaponifiable  matters  deduced  in  these  two  ways  gives  a  rough 
valuation  of  the  cholesteroid  bodies  present,  the  proportion  of 
these  latter  being  approximately  deducible  by  multiplying  the 
difference  by  10. 

The  following  analyses  of  Yorkshire  grease  (method  of  analysis 
not  stated)  are  given  by  G.  H.  Hurst  f  as  fairly  typical : — 


Sp.  gr.  at  15°-5C.,   . 

J»  55      98  ,, 

Water,    . 
Fatty  acid, 
Neutral  oil,      . 
Unsaponifiable  oil,  . 
Ash, 


1 

2 

3 

4 

: 

0-9391 
0-8900 

0-9417 
0-8952 

... 

0-9570 
0-8720 

. 

0-98 
18-61 
68-62 
11-68 
O'll 

1-53 
24-25 
58-25 
15-83 
0  14 

1-21 
24-15 
30-02 
44-44 
0-18 

0-94 
26-43 
16-86 

55-77 
trace 

100-00 

100-00 

100-00 

100-00 

*  Jaurn.  Soc.  Chnn.  Iml.,  1892,  p.  144. 
t  Journ.  Soc.  Chem.  2nd.,  1889,  p.  90. 


DISTILLED    GREASE.  277 

Thus,  the  higher  the  density,  the  greater  the  percentage  of 
imsaponifiable  oil.  Such  greases  generally  melt  at  near  44°  C. ; 
they  can  be  saponified  with  alkalies,  but  only  imperfectly  ;  the 
flashing  point  is  usually  near  220°  C.  (p.  128). 

Distilled  Grease.  —  Yorkshire  grease  from  wool,  and  analo- 
gous recovered  greases  from  other  sources,  are  rarely  sufficiently 
free  from  odour  and  otherwise  of  general  good  character,  to 
enable  them  to  ba  directly  used  for  anything  but  the  coarsest 
purposes  —  e.g.,  cart  grease,  and  similar  rough  lubricating 
materials,  such  as  that  required  for  the  hot  axles  of  tin  plate 
rolling  machines.  When  subjected  to  distillation  in  cast  iron* 
stills  of  about  1,000  gallons  capacity,  holding  about  4  tons  of 
grease,  a  variety  of  products  are  obtained,  to  some  extent  varying 
with  the  quality  and  nature  of  the  grease.  The  stills  are  first 
heated  for  10  to  16  hours  with  free  fire  to  drive  off  water,  and 
then  for  20  to  24  hours  more  with  superheated  steam,  during 
which  time  a  pale  yellow  product  comes  over,  known  as  "  first 
distilled  grease,"  sometimes  preceded  by  a  lighter  "  spirit  oil/' 
sometimes  not.  After  the  "first  distilled  grease,"  "green  oil" 
comes  over,  sometimes  used  for  coarse  lubricating  greases,  but 
more  often  put  back  into  the  still  and  worked  over  along  with 
the  next  batch.  Finally,  the  distillate  comes  over  as  a  thick  oil, 
when  the  operation  is  regarded  as  finished  ;  the  fires  are  drawn, 
the  superheated  steam  turned  off,  and  the  pitch  run  out  of  the 
still :  100  parts  of  Yorkshire  grease  thus  treated  gave — 


Pitch,    .  .  14-1  parts. 

Green  oil,          .  .  .  .  15  "5     ,, 

First  distilled  grease,   .  .  .  45*5     ,, 

Spirit  oil,  ....  4'1     ,, 

Water  and  loss,  .  .  .  20'S     ,, 

100-0 


The  pitch  thus  obtained  forms  a  useful  lubricant  for  the  necks  of 
hot  rollers. 

The  "  first  distilled  grease  "  is  sometimes  allowed  to  "  seed  "  or 
crystallise  in  the  usual  way  (Chap,  xvi.),  and  then  pressed  in  a 
hydraulic  press,  so  as  to  obtain  a  liquid  "  oleine "  and  a  solid 
"  stearine  ';  in.  about  the  relative  proportions,  2  to  1  ;  the  oleine 
that  exudes  spontaneously  from  the  crystallised  cake  before 
pressing,  is  sometimes  collected  apart  and  designated  "No.  1  oil." 
Or  the  grease  is  distilled  a  second  time,  so  as  to  obtain  about 

*  Cast  iron  is  much  less  rapidly  corroded  by  the  fatty  acids  than  wrought 
iron— ride  G.  H.  Hurst,  loc.  cit.  sttpra. 


278  OILS,    FATS,    WAXES,    ETC. 

96  per  cent,  of  "  second  distilled  grease,"  and  4  per  cent,  of 
"  soft  pitch." 

The  "  spirit  oil,"  as  it  first  runs  from  the  stills,  is  pale  yellow 
in  colour,  but  darkens  on  keeping,  probably  by  oxidation,  like  the 
somewhat  analogous  oils  obtained  on  the  redistillation  of  bone 
tar  and  other  products  of  destructive  distillation  ;  it  contains  a 
small  quantity  of  free  fatty  acids,  equivalent  to  4  or  5  per  cent, 
of  oleic  acid;  on  redistillation,  it  begins  to  boil  at  near  150°  C., 
about  two-thirds  distilling  below  240°,  and  seven-eighths  below 
320°.  It  finds  a  limited  use  in  making  black  varnish.  Of  what 
constituent  of  the  original  grease  it  is  a  product  of  decomposition 
by  heat,  is  not  known  certainly ;  possibly  it  is  derived  from 
cholesterol,  ttc.,  but  as  hydrocarbons  are  always  formed  in  small 
quantity  in  the  redistillation  of  "  red  oils  "  (crude  oleic  acid)  and 
similar  substances  containing  little  or  no  constituents  analogous 
to  cholesterol,  it  is  more  probable  that  it  comes  from  the  decom- 
position of  the  oleic  acid  present. 

"  Distilled  grease  "  is  of  pale  yellow  colour,  and  of  granular 
texture  ;  two  samples  gave  the  following  numbers  (Hurst) : — 


First  Distilled  Grease. 

Second  Distilled  Grease. 

Water,     
Free  acid,         .... 
Uusapornfiable  matter,    . 
Neutral  oil,      .... 

0-98 
63-12 
12-88 
23-02 

1-04 
66-f>6 
1324 
19-16 

10000 

100-00 

Lewkowitsch  found  a  considerably  larger  percentage  of  hydro- 
carbons in  a  sample  of  distilled  grease  examined  by  him,  viz.  : — 

Free  fatty  acids  (molecular  weight  =  286),    .         .     54-91  per  cent. 
Combined  fatty  acids  (molecular  weight  =  327'5),.       7  "02        ,, 
,Unsaponifiable  matters,          .         .         .         .         .38*80        ,, 


100-73 


The  combined  fatty  acids  would  represent  about  11-28  per  cent, 
of  compound  ethers  ("neutral  fat"),  leaving  34-54  per  cent,  of 
hydrocarbons. 

The  "  stearine  "  obtained  from  distilled  grease  by  pressure  is 

a  hard  pale  yellow  greasy  solid ;  that  from  the  "  first  distilled 

grease"  is  darker  than  that  from  "  second  distilled  grease,"  but 

vhas  usually  a  slightly  higher  melting  point.      Apparently  the 

fatty  acids  present  have  a  higher  molecular  weight  than  stearic 


ENGINE    WASTE    GREASE,    FULLERS    GREASE. 


279 


acid,  inasmuch  as  the  free  acid  found  on  analysis,  when  cal- 
culated as  stearic  acid  and  added  to  the  other  constituents,  gives 
a  total  considerably  under  100  ( Hurst).  *  Thus — 


Stearin  e. 

From  First  Distilled 
Grease. 

From  Second  Distilled 
Grease. 

Sp.  Gr.  at  15°  -5,  .... 

98,        .... 

0-9044 

0-9193 
0-836 

Water,           

Free  acid  calculated  as  stearic  acid, 
Unsaponifiable  oil, 
Neutral  oil,  

1-48 
76-3 
0-4 

7-7 

0-6 
88-6 
0-49 
2-11 

85-88 

91-80 

Melting  point,       .... 
Solidifying  point, 

57°  (134°F.) 
53-5  (128°F.) 

48°  (118°  P.) 
45°(113°F.) 

The  oleine  simultaneously  obtained  is  pale  when  fresh,  but 
gradually  darkens,  probably  owing  to  the  presence  of  iron 
derived  from  the  press  or  the  tanks, in  which  it  is  stored.  It  is 
generally  known  in  the  district  of  production  as  "  wool  oil," 
because  it  is  chiefly  used  for  oiling  woollen  yarns,  £c.;  lubricating 
greases  and  soap  are  sometimes  prepared  from  it ;  but  for  the 
latter  purpose  it  is  not  at  all  well  suited  on  account  of  the  large 
proportion  of  unsaponifiable  matters.  It  varies  much  in  com- 
position, even  when  from  the  same  maker,  on  account  of  the 
varying  composition  of  the  Yorkshire  grease  originally  employed, 
the  neutral  oil  amounting  to  between  0  and  28  per  cent.,  and  the 
unsaponifiable  oil  to  between  10  and  38,  whilst  the  free  acid 
(calculated  as  oleic  acid)  constitutes  53  to  65  per  cent.  The 
Hashing  point  usually  lies  between  322°  F.  and  342°  F.  (Hurst). 

Engine  Waste  Grease  and  Fuller's  Grease. — The  grease 
recovered  from  greasy  engine  waste  (p.  236)  is  closely  akin  to 
that  obtained  from  soap  suds ;  but  owing  to  the  large  use  of 
hydrocarbons  as  ingredients  in  lubricating  oils  at  the  present 
day,  it  is  usually  much  less  valuable,  the  yield  of  solid  "stearine" 
being  but  small,  and  the  "oleine"  containing  large  quantities 
of  unsaponifiable  hydrocarbons.  When  the  spindles,  &c.,  are 
lubricated  with  tolerably  pure  vegetable  oils  or  with  sperm 
oil,  &c.,  a  much  better  form  of  grease  results ;  but  this  is 
comparatively  rare. 

Grease  recovered  from  silk  soap  suds  and  soap  baths  from 
cotton  dyeing  works,  &c.,  mostly  consists  of  free  fatty  acids  with 

""  The  presence  of  stearolactone  (p.  170)  might  possibly  explain  thfe 
apparent  deficiency  in  free  acids. 


280  OILS,    FATS,    WAXES,    ETC. 

but  little  unsaponifiable  matter,  and  is  often  clean  enough  to  be 
used  directly  for  soapmaking.  Its  commercial  valuation  for  such 
purposes  is  generally  effected  by  determining  the  percentage  of 
water  present  (p.  122),  and  of  matters  insoluble  in  alcohol  (un- 
saponifiable matters),  subtracting  the  sum  from  100,  and  reckoning 
the  difference  as  available  fatty  acids.  When  too  dirty  for  use 
in  even  the  coarsest  soap,  such  grease  is  either  directly  utilised 
for  lubricating  materials  of  the  roughest  kind,  or  is  distilled 
by  means  of  superheated  steam,  and  the  distillate  pressed  for 
stearine  and  oleine. 


CLASSIFICATION    OF   OILS,    ETC.  281 


5.  Classification  and  Uses  of  Fixed  Oils,  Fats, 
Waxes,  &c.;  Adulterations. 


CHAPTER  XIII. 
CLASSIFICATION. 

In  accordance  with  their  ordinary  physical  texture,  sources 
(whether  animal  or  vegetable),  and  essential  chemical  nature, 
the  fixed  oils,  fats,  butters,  and  waxes,  <fcc.,  may  be  conveniently 
divided  into  twelve  classes,  falling  into  two  principal  divisions, 
according  as  the  main  components  are  of  glyceridic  or  non- 
glyceridic  nature. 

DIVISION  I. — ESSENTIALLY  GLYCERIDIC. 
A .  Fluid  at  Ordinary  Temperatures  : — 

1.  Non-drying  Oils — 

Vegetable — 

(1)  Olive  (almond)  class. 

(2)  Rape  (colza)  class. 

(3)  Ricinoleic  (castor)  class. 

Animal — 

(4)  Lard  oil  class. 

2.  Intermediate :  Drying  Qualities  possessed  to  a  limited 

extent : — 
Vegetable — 

(5)  Cotton  (sesame)  class. 

Animal — 

(6)  Train,  fish,  and  liver  class. 

3.  Drying  Oils  :  well  marked  Drying  Qualities  : — 

Vegetable — 

(7)  Linseed  class. 


382  OILS,    FATS,    WAXES,    ETC. 

B.  Solid  or  Semisolid  at  Ordinary  Temperatures  : — 

Vegetable — 

(8)  Palm  butter,  and  Japanese  wax  class. 

Animal — 

(9)  Tallow,  lard,  and  cow's  butter  class. 

DIVISION  II. — ESSENTIALLY  NON-GLYCERIDIC. 

A.  Fluid  at  Ordinary  Temperatures  : — 

Animal — 

(10)  Sperm  oil  class. 

B.  Solid  or  Semisolid  at  Ordinary  Temperatures  : — 

Vegetable — 

(11)  Carnauba  wax  class. 

Animal — 

(12)  Beeswax  and  spermaceti  class. 

CLASS  I.— OLIVE  (ALMOND)  CLASS. 

A  large  number  of  oils  are  known  completely  fluid  at  ordinary 
temperatures  and  not  congealing  until  greatly  chilled,  consisting 
chiefly  of  olein  with  smaller  quantities  of  more  solid  glycerides 
(myricin,  palmitin,  stearin,  arachin,  &c. ),  and  in  some  cases  small 
admixtures  of  glycerides  of  other  kinds  ;  as  a  rule,  however, 
glycerides  of  the  "drying  oil"  division  are  either  absent 
altogether,  or  only  present  in  very  small  quantities,  so  that  oils 
of  this  class  are  practically  non-drying.  The  presence  of  the 
other  constituents  raises  the  relative  density  somewhat  above 
that  of  pure  olein  (near  0-905  at  15°),  usually  to  between  -913 
and  '92-1  •  and  at  the  same  time  tends  to  dimmish  the  iodine 
number  below  86 -2  per  cent.,  the  calculated  value  for  pure  olein 
(p.  180),  excepting  in  those  cases  where  a  notable  admixture 
•of  less  saturated  glycerides  is  present,  when  the  superior  iodine 
absorbing  power  of  these  ingredients  slightly  raises  the  value 
instead  of  lowering  it.  The  calculated  saponification  equivalent 
of  pure  olein  is  294'7  (p.  158) ;  that  of  an  oil  of  this  kind 
generally  differs  but  little  therefrom,  being  a  little  higher  or  a 
little  lower,  according  as  the  other  constituents  have  mean 
equivalent  weights  above  or  below  this  value.  The  proportion 
of  glycerides  other  than  those  of  oleic  and  the  solid  fatty  acids 
is  not  large  enough  to  interfere  with  the  production  of  a  tolerably 
hard  solid  elaidin  with  nitrous  acid  (p.  137),  nor  to  cause  that 
heat  evolution  on  mixture  with  sulphuric  acid  to  be  large 
(p.  147). 

The  chief  oils  of  commercial  or  local  importance  belonging  to 


VEGETABLE    OLEINES.  283 

this   class   that  have   been   investigated  to  any  extent  are  as 
follows  : —  . 


Name  of  Oil.  Source. 


Almond  oil  (sweet),  .         .        Amyydalus  communis  (Prunus  amyg- 

dalux),  var.  dulcis. 
,,  var.  amara. 


(bitter), 
Arachis  oil  (grouudimt  oil), 
Beechmast  oil, 
Ben  oil,    .         .         . 

Hazelnut  oil,    . 
Olive  oil, 


Araclii*  hypogcea. 

Fagus  sylvatica. 

Morinrja  pterygosperma ;    M.    apt  era 

(Guilandia  moringa). 
Corylus  arellana. 
Olea  Europcea  sylvestris  :  0.  E.  satira. 


Plum,    peach,   cherry,   and         )     P™nu*     domestica  ;      P.    persica 

apricot  kernel  oils,     .         .  £  ,  arme^aca  *  „  P'      «™ 

P.  ongandaca ;   P.  serotina. 


Tea  seed  oil, 


Camellia    theifera  •     C.    oleifera  : 
C.  drupifera. 


Besides  these,  however,  a  large  number  of  oils  are  in  use  to 
varying  extents  in  different  countries  for  edible  purposes,  burning, 
.anointing,  <fcc.,  many  of  which  agree  in  their  general  physical 
characters  with  the  above,  more  especially  in  being  practically 
non-drying  in  character  and  only  solidifying  at  low  temperatures, 
And  hence  presumably  consisting  essentially  of  olein ;  the 
chemical  examination  of  most  of  these,  however,  has  not  yet 
been  undertaken ;  and  as  yet  they  are  but  little  exported,  and 
consequently  have  not  found  their  way  into  general  trade  in  any 
large  quantities  (vide  pp.  287,  296). 

Vegetable  Expression  Oleines.  — Semisolid  vegetable  tal- 
lows and  butters,  when  subjected  to  cold  pressure,  yield  a  solid 
mass  of  higher  fusing  point  together  with  a  comparatively  fluid 
oil  or  oleine  ;  in  certain  cases,  more- especially  for  the  production 
of  the  higher  fatty  acids  for  candle  making,  this  treatment  is 
resorted  to  in  order  to  partially  separate  the  more  fluid  glycerides 
from  the  others.  Cokernut  and  palm  kernel  butters  when  thus 
treated  yield  fluid  oleines,  solidifying  a  few  degrees  above  0° ; 
these  consist  partly  of  oleic  glyceride,  partly  of  the  glycerides  of 
the  acetic  series  of  lower  molecular  weight  contained  in  the 
original  butters  ;  and,  in  consequence  of  the  presence  of  these 
latter  in  considerable  quantity,  possess  a  somewhat  different 
composition  from  ordinary  oils  of  the  olive  class — e.g.,  the  iodine 
.absorption  is  much  lower  (often  below  30  to  40)  owing  to  the 
relatively  small  amount  of  oleic  glyceride  present ;  and  similarly, 
the  heat  development  on  mixture  with  sulphuric  acid  is  below 
that  observed  with  olive  oil  (cokernut  oleine  =  26°  to  27° ;  olive 
oil  =  41°  to  43° — A.  H.  Allen).  On  account  of  the  absence  of 
linolic  and  similar  glycerides,  these  products  are  almost  com- 
pletely non-drying. 


284 


OILS,    FATS,    WAXES,    ETC. 


CLASS  II.— RAPE  (COLZA)  CLASS. 

The  characteristic  property  of  this  class  of  oils  is  that  of 
possessing  a  much  higher  saponification  equivalent  than  the  oils 
of  Classes  I.  and  III.  in  virtue  of  the  presence  of  considerable 
quantities  of  a  higher  homologue  of  oleic  acid — viz.,  erucic  acid, 
(X2H4.2O0,  crystallisable  and  melting  at  34°.  In  the  case  of 
colza  oil  another  acid,  rapic  acid,  C1SH0)4O.},  isomeric  with  ricin- 
oleic  acid,  has  been  stated  to  be  also  present  in  considerable 
quantity  (p.  41).  More  precise  information,  however,  is  decidedly 
wanted  as  regards  the  constituents  not  only  of  the  lesser  known 
members  of  the  group,  but  also  of  those  most  commonly 
occurring. 

The  specific  gravity  is  relatively  low,  mostly  below  -918  ;  the 
.saponification  equivalent  usually  lies  between  315  and  325, 
whilst  the  iodine  number  is  between  95  and  105,  indicating  the 
presence  of  a  certain  amount  of  glycerides  of  linolic  character,* 
a  result  also  borne  out  by  the  possession  of  some  degree  of  drying 
character  by  the  oils  themselves,  not,  however,  of  a  strongly 
marked  kind. 

Oils  of  this  class  do  not  give  a  particularly  solid  elaidin  re- 
action with  nitrous  acid,  buttery  masses  being  usually  formed 
which  often  separate  on  standing  into  two  portions,  one  solid  and 
the  other  liquid. 

The  principal  oils  of  this  class  are  those  undermentioned,  but 
in  all  probability  many  of  the  lesser  known  oils  are  of  similar  com- 
position, judging  from  their  general  physical  characteristics  :  — 


Name  of  Oil. 

Source 

Colza  (rape)  oil, 

Hedge  mustard  oil  (hedge           \ 
radish  oil),    .         .         .         .  J 
Mustard  oils  (black  and  white  ;  } 
Chinese  cabbage  oil),    .         .  1 

Different  cultivated  varieties  of 
Brasxica  campestris. 
Raphanus  raphaniMrum   (Raphanis- 
trum  arrense). 
Sinapis  nirjra  :  S.  alba  ;  and  other 
species  of  Sinapis. 
Uaphanns  Kotivus. 

CLASS  III.— CASTOR  OIL  CLASS. 

In  this  class  of  oils  the  prevailing  glyceride  is  that  of  an  oxy- 
acid,  such  as  ricinoleic  acid,  which  gives  to  oils  of  this  description 
peculiar  chemical  characteristics.  Comparatively  few  oils  besides 
castor  oil  have  been  sufficiently  closely  examined  to  render  it 
certain  that  they  belong  to  this  class  ;  but  it  is  highly  probable 
that  several  of  the  lesser  known  oils  used  locally  for  edible 

*  The  calculated  value  for  erucin  is  72 '4,  that  for  olein,  86 "2. 


ANIMAL    NON-DRYING    OILS.  285 

purposes,  or  as  lamp  oils,  in  different  parts  of  the  world,  really 
consist  to  a  greater  or  lesser  extent  of  oxy-acid  glycerides. 

A  tolerably  high  specific  gravity,  from  -950  to  -970,  is  possessed 
by  oils  of  this  class,  and  a  saponification  equivalent  of  305  to  315 
(calculated  value  for  ricinoleiii  =  310-67).  The  elaidins  are  soft 
and  buttery.  The  following  oils  appear  to  contain  more  or  less 
considerable  proportions  of  oxy-acid  glycerides  : — 


Name  of  Oil.  Source. 


Castor  oil,          .         .         .        Ricihux  communi*  (var.  minor  and  major). 
C ureas  oil  (purqueiraoil),.        Jatropha  curcaa  (Curcas  purgans). 
Grape  seed  oil,  .         .         .         Vitls  vinifera. 


CLASS    IV.— ANIMAL   NON-DRYING    OILS- 
LARD   OIL   CLASS. 

When  comparatively  solid  animal  fats  are  subjected  to  a 
regulated  pressure  (p.  231),  a  mechanical  separation  of  the  solid 
and  liquid  constituents  is  effected  if  the  temperature  be  suitably 
adjusted ;  the  fluid  substances  thus  expressed  are,  strictly 
speaking,  the  only  products  to  which  the  term  "  oleine "  is 
applicable  (besides  the  analogous  fluid  constituents  of  vegetable 
oils);  but  in  commercial  practice  the  fluid  free  fatty  acids 
separated  by  similar  means  from  the  products  of  saponification 
of  such  fats,  are  also  designated  "  oleines,"  as  also  are  the 
analogous  fluid  acids  obtained  from  steam-distilled  fatty  acids 
from  greases  of  various  kinds  (p.  110);  further,  oils  treated  with 
sulphuric  acid  (Turkey  red  ohs)  are  often  termed  "oleine"  in 
the  cotton  dyeing  industry.  Accordingly,  the  glyceridic  ex- 
pression products  are  more  usually  spoken  of  as  "  oils  "  (e.g., 
tallow  oil)  than  as  oleines  ;  although,  even  then,  confusion  is 
not  always  avoided,  since  the  terms  "  tallow  oil  "  and  "  red  oil  " 
are  sometimes  also  applied  to  the  expressed  crude  oleic  acid  of 
the  candle  maker. 

Products  of  this  class  closely  resemble  vegetable  oils  of  Class  I., 
especially  when  free  from  any  animal  or  rancid  odour  betraying 
their  origin.  According  to  the  way  in  which  the  expression  is 
effected  (more  especially  as  regards  temperature),  they  contain 
varying  quantities  of  the  solid  constituents  ("  stearines,"  chiefly 
palmitin  and  actual  stearin — i.e.,  stearic  glyceride)  in  solution, 
but  otherwise  consist  essentially  of  olein  (oleic  glyceride).  They 
usually  have  a  specific  gravity  of  about  -915  or  -916  at  15°,  and 
solidify  within  a  few  degrees  of  0°  C.  (above  or  below).  With 
nitrous  acid  they  form  firm  solid  elaidins ;  with  sulphuric  acid 
(Maumene's  test)  the  heat  evolution  is  small,  as  compared  with 
most  other  oils.  The  chief  oils  of  the  class  are  : — 


286 


OILS,    FATS,    WAXES,    ETC. 


Name  of  Oil. 


Source. 


Lard  oil,          .... 
Neat's  foot  oil,  horse  foot  oil,  \ 
sheep's  trotter  oil,      .         .  / 
Tallow  oil,      . 


Hogs'  lard  subjected  to  expression. 
The  "  feet"  (hoofs  and  hocks)  of  oxen, 

horses,  and  sheep. 
Ox   and   mutton   tallow   subjected    to 

expression. 


CLASS    V.—  SESAME   OR   COTTON    SEED    CLASS- 
VEGETABLE  SEMI-DRYING  OILS. 

The  distinctions  between  this  class  of  oils  and  those  of  Classes 
I.  and  VI.  are  not  always  very  clearly  marked,  the  differences 
being  rather  of  degree  than  of  kind,  chiefly  consisting  in  the 
presence  of  distinctly  larger  proportions  of  glycerides  of  the 
drying  class  than  are  present  in  non-drying  oils  of  Class  I., 
although  these  ingredients  are  not  contained  in  sufficient 
quantity  to  give  true  drying  qualities,  such  as  are  possessed  by 
oils  of  Class  VI. — i.e.,  the  power  of  absorbing  oxygen  from  the 
air,  and  becoming  a  solid  varnish-like  mass.  Accordingly,  the 
effect  of  the  elaidin  test  (p.  137)  is  to  form  a  soft  solid  mass,  far 
inferior  in  hardness  and  consistency  to  that  furnished  by  typical 
non-drying  oils,  such  as  olive  or  arachis  oil,  but  considerably 
more  solid  in  character  than  the  soft  nearly  fluid  products  formed 
by  the  true  drying  oils,  such  as  linseed  oil. 

In  general,  the  specific  gravity  at  15°  is  a  little  higher  than 
that  of  oils  of  Class  I.,  mostly  lying  between  -923  and  -'J35  :  and 
the  iodine  absorption  is  similarly  raised  considerably  above  86*2, 
the  theoretical  value  for  pure  olein.  In  most  cases,  solid 
glycerides  (palmitin,  stearin,  <tc.)  are  present  to  a  greater  or 
lesser  extent,  together  with  small  quantities  of  glycerides  of  oxy- 
acids.  The  following  are  the  best  known  oils  of  the  class  : — 


Name  of  Oil. 


Camelina  oil  (German  oil  of 
sesame  or  gold  of  pleasure 
oil) 

Cotton  seed  oil, 


Cress  oil,          .... 
Madia  oil,        .... 
Maize  oil,         .... 
Niger  oil  (ramtil  oil), 
Sesame  oil  (gingelly  oil,  til  oil, 

benne  oil),    . 
Sunflower  oil, .... 


Source. 


Camelina  saliva. 

Gow/pium    herbaccum  ;     G.    hirautum  ; 

G.    barbadense ;     G.    arboreum ;     G. 

relirjiosum. 
Lepidium  sativum. 
Madia  sativa. 
Zea  mnis. 
Guizotia  oltifera. 

Sesamum  orientale. 

Helianthufi  annuus  ;  H.  pereniri*. 


LESSER    KNOWN    VEGETABLE    OILS.  287 

Lesser  Known  Vegetable  Oils. — In  addition  to  the  leading 
vegetable  oils  above  mentioned  belonging  to  Classes  I.,  II.,  III., 
and  V.,  a  large  number  of  other  oils  are  locally  known  and  used  to 
a  considerable  extent  in  various  parts  of  the  world.  In  most 
instances  nothing  whatever  is  known  as  to  the  chemical  constitu- 
tion of  these  substances;  judging  from  their  general  physical  char- 
acters they  are,  as  a  rule,  either  nondrying  oils  of  the  olive  class, 
or  semidrying  oils  of  the  cotton  seed  type;  some,  however,  in  all 
probability  are  more  or  less  akin  to  rape  or  to  castor  oil.  Amongst 
these  lesser  known  imperfectly  drying  oils  may  be  mentioned 
that  derived  from  the  soja  bean  (Soja  hispida  or  Glycine  soja)  of 
China  and  Japan,  where  both  the  beans  themselves  and  the  oil 
thence  expressed  are  important  articles  of  food.  Recently  the 
plant  has  been  introduced  into  Europe ;  the  seeds  yield  about  a 
sixth  of  their  weight  of  oil  by  pressure,  furnishing  an  excellent 
oilcake  for  cattle  feeding.  The  oil  itself  thickens  on  chilling,  and 
when  exposed  to  air  oxidises  somewhat  rapidly. 

The  nuts  of  the  candlenut  trees  (Aleurites  moluccana,A.  triloba; 
Jatropha  moluccanum,  Croton  moluccanum\  found  in  the  Eastern 
Archipelago,  Malay,  Cochin  China  and  Southern  China ;  Cali- 
fornia, Chili  and  Venezuela  ;  Bourbon,  Mauritius,  Jamaica,. 
Polynesia  and  North  Australia)  furnish  similar  oils,  chiefly  used 
for  cooking  and  burning,  but  sometimes  possessing  sufficient 
drying  power  to  be  capable  of  use  for  painting  purposes  in  hot 
climates.  In  different  countries  the  oil  is  known  by  different 
names — e.g.,  Bankulnut  oil,  Kekune  oil,  &c.  According  to  Lach 
a  sample  of  candlenut  fat  fusing  at  24°  and  solidifying  at  21° 
yielded  fatty  acids  melting  at  65° -5  and  solidifying  at  56°  :  the 
iodine  number  was  118,  indicating  the  presence  of  a  considerable 
proportion  of  drying  oils. 

L.  Field  describes  candlenut  oil  as  limpid  and  sweet,  not  soli- 
difying at  0°,  and  capable  of  forming  a  fine  waxy  looking  soap 
by  the  cold  process.  It  is  stated  to  be  well  adapted  for  cloth 
dressing  and  to  be  largely  exported  to  Europe  for  soapmakingr 
but  does  not  appear  to  be  much  used  in  England  for  those 
purposes.  The  nuts  are  extremely  hard,  so  as  to  be  cracked 
by  ordinary  machinery  only  with  difficulty  ;  when  strung  on  a 
twig  they  can  be  burnt  like  a  tallow  candle,  whence  the  ordinary 
name. 

The  seeds  of  various  species  of  pine  (Pinus  sylvestris,  P.  cibiesy 
P.  picea  furnish  by  expression  or  solvents  imperfectly  drying  oils 
used  to  some  extent  for  burning  and  other  purposes  ;  these  vary 
in  specific  gravity  from  '925  to  '931  at  15°,  and  mostly  thicken  at 
about  —  15,  solidifying  at  about  —  '27°. 

Croton  oil,  from  Croton  tiglium,  is  possessed  of  weak  drying 
characters,  but  has  a  composition  differing  in  many  respects  from 
most  of  the  oils  of  the  nondrying  and  semidrying  classes.  The 
specific  gravity  of  the  fresh  oil  is  '942  at  15°,  older  oil  that  has 


288  OILS,    FATS,    WAXES,    ETC. 

absorbed  oxygen  from  the  air  being  more  dense,  about  .'955  ; 
solidification  occurs  at  about  -  16°.  The  oil  is  strongly  purgative 
when  taken  in  small  doses  internally,  and  vesicatory  when  applied 
to  the  skin ;  it  does  not  form  any  solid  elaidin  with  nitrous  acid. 
It  mainly  consists  of  glycerides,  and  on  saponification  furnishes 
stearic,  palmitic,  myristic,  lauric,  caproic,  valeric,  butyric,  .acetic, 
and  formic  acids  of  the  acetic  family,  together  with  tiglic  (methyl 
•cro  tonic),  and  crotonic  acids  of  the  oleic  series.  Oleic  acid  has 
been  stated  to  be  present  by  some  investigators,  and  to  be  absent 
by  others,  a  nonvolatile  "  crotonoleic  acid "  yielding  a  barium 
salt  soluble  in  alcohol  having  also  been  found.  The  vesicatory 
agent  is  believed  to  be  "  crotonol,"  a  semisolid  body  indicated  by 
the  formula  C9HUO2 ;  this  is  not  identical  with  the  purgative 
principle,  the  nature  of  which  is  uncertain. 

An  excellent  fatty  oil  is  largely  used  in  Morocco,  derived  from 
the  Argan  tree  (Argania  sideroxylon,  Elwodendron  argan,  or 
Sideroxylon  spinosum)  :  the  fruit  is  fleshy  and  is  eaten  greedily 
by  sheep  and  goats,  cows  and  camels,  but  the  kernels  or  stones 
are  hard  and  bony,  and  are  consequently  rejected  by  the  animals. 
These  stones  are  collected  and  cracked,  and  the  inner  white 
kernels  carefully  roasted,  ground,  and  kneaded  with  a  little 
warm  water,  whereby  the  oil  is  gradually  expelled,  more  water 
being  added  from  time  to  time,  and  the  mass  kneaded  until  no 
more  oil  exudes.  After  settling  the  oil  is  a  clear  light  brown 
iluid,  often  of  somewhat  rancid  flavour  and  odour;  it  is  largely 
used  by  the  Moors  as  an  edible  oil,  somewhat  cheaper  than  olive 
oil.  Somewhat  similar  oils  are  obtained  from  the  kernels  of  the 
fruit  of  titapliylea  pinnata  (bladdernuts)  in  Eastern  Europe  ;  the 
berries  of  the  dogwood  (Cornus  sanguined)  in  Italy,  Cashmere, 
and  Siberia ;  the  seeds  of  the  spindel  tree  (Euonymus  europoeus) 
of  Central  Europe ;  horsechestnuts  (^Esculus  liippocastanum)  ; 
and  the  seeds  of  Sarcostigma  Kleinii  (known  as  Adul  or  Odal  oil 
in  Southern  India),  of  several  Hibiscus  species,  and  of  Penta- 
clethra  macrophylla  (Owala  oil  of  the  Gaboon,  Opochala  oil  of 
Fernando  Po). 

The  Brazil  nut  or  Castanha  (BertJiolletia  excelsa)  of  South 
America  yields  a  clear  yellow  bland  oil  closely  resembling  that 
of  almonds,  soon  becoming  rancid  ;  the  edible  seeds  of  the 
Telfairia  pedata  of  South-east  Africa  furnish  a  similar  oil,  said 
to  be  equal  to  the  finest  olive  oil.  Pumpkin  seed  oil  (Curcurbita 
pepo)  is  a  clear  sweet-tasting  oil,  yellowish  or  nearly  colourless 
when  obtained  by  cold  pressure,  possessed  of  only  faintly  marked 
drying  qualities  ;  its  relative  density  is  '923  at  15° ;  at  -  15° 
it  solidifies  to  a  greyish-yellow  mass.  Similar  oils  are  obtain- 
able from  the  seeds  of  other  curcurbitaceous  plants— e.g.,  the 
watermelon  (Cucumis  citrullus),  sweet  melon  (C.  melo),  gherkin 
(C.  sativus),  colocynth  (C.  colocynthis},  Arc.  The  oil  of  the 
Boma  nut  (Pycnocoma  macrophylla)  is  sweet  and  bland,  and  is 


LESSER    KNOWN    VEGETABLE    OILS.  289 

much  used  for  cooking  by  the  natives  of  Central  Africa ;  that  of 
the  Cashew  or  Acajou  nut  (Anacardium  occidentals)  is  similarly 
employed  in  the  East  and  West  Indies  and  the  West  Coast  of 
Africa;  in  the  Brazils  it  has  been  in  use  for  centuries  as  an 
edible  oil ;  it  is  a  light  yellow  sweet-tasting  oil  much  like  that  of 
almonds,  of  relative  density  -916.  Mango  seeds  (Mangifera 
indica)  and  pistachio  nuts  (Pistachio,  vera)  yield  similar  oils,  as 
also  do  the  fruit  kernels  of  BucJianania  latifolia,  a  forest  tree 
common  in  Coromandel,  Malabar,  and  Mysore ;  the  oil  from  the 
last  is  limpid  and  of  a  pale  straw  colour  and  is  sometimes  known 
as  Chironji  oil.  Various  species  of  (Enocarpus  bear  oleaginous 
nuts  furnishing  sweet  cooking  and  eating  oils,  known  in  Para  as 
"coumu  oil,"  resembling  olive  oil  but  becoming  solid  much  more 
readily  011  chilling  ;  hickory  nuts  (Gary a  olivceformis),  M'poga 
nuts  (common  in  the  Gaboon),  breadnuts  (OmpJialea  diandra 
and  0.  triandra — St.  Domingo  and  Jamaica),  and  many  other 
lesser  known  nuts  and  seeds  are  also  sources  of  similar  pro- 
ducts. 

According  to  J.  R.  Jackson,*  a  large  number  of  new  oil  seeds 
have  come  into  the  English  market  of  late  years  from  the 
West  Coast  of  Africa,  but  the  supplies  have  mostly  been  inter- 
mittent ;  some  few  are  particularly  well  adapted  for  use  were  a 
constant  supply  forthcoming,  more  especially  the  seeds  of  the 
Telfairia  occidentalis  (a  cucurbitaceous  plant) ;  the  Myristica 
angolensis  (a  scentless  nutmeg) ;  the  Hyptis  spicigera  (a  herbaceous 
labiate  plant);  the  Poly  gala  rarifolia  ("Maluku"  seeds);  the 
Lophira  alata  ("  Meni "  or  "  Laintlaintain "  seeds,  from  one  of 
the  Dipterocarpece ;  Senegambia  and  Sierra  Leone) ;  and  the 
Penteclethra  macropJiylla  (a  leguminous  tree,  the  "  Owala  "  of  the 
Gaboon,  and  the  "  Opachala  "  of  the  Eboe  country.  "  M'poga," 
"  Mabo,"  and  "  Niko  "  nuts  also  furnish  oils  of  a  character  that 
might  render  them  very  useful. 

Similar  remarks  apply  to  the  oil  bearing  produce  of  many 
other  countries  ;  in  many  instances  the  oils  thence  obtainable  are 
of  characters  so  good  for  a  variety  of  purposes  as  to  leave  little 
doubt  that  a  considerable  amount  of  trade  in  such  materials  will 
hereafter  become  developed  whenever  the  conditions  are  realised 
necessary  for  the  economical  growth  of  the  trees  and  plants,  and 
the  harvesting  of  their  seeds,  nuts,  or  other  fruits,  &c.,  or  for  their 
treatment  on  the  spot  for  the  extraction  of  oil ;  together  with  the 
necessary  opening  up  of  the  districts  for  transport  purposes,  so 
as  to  enable  regular  supplies  to  be  obtained.  In  all  probability 
the  uncertainty  as  to  what  quantity  of  material  could  be  obtained, 
and  its  price,  has  largely  militated  against  the  importation  into 
Europe  of  numerous  raw  materials  of  the  kind,  manufacturers 
not  caring  to  expend  time,  skill,  and  capital  in  working  up  sale- 
able products  until  assured  on  these  points. 

*  Journal  Society  of  Arts,  1891,  40,  p.  122. 

19 


290  OILS,    FATS,    WAXES,    ETC. 


€LASS  VI.— DRYING  OILS— LINSEED  OIL  CLASS. 

The  drying  oils  proper  principally  differ  from  the  semi-drying 
oils  in  containing  much  larger  proportions  of  the  glycerides  of 
the  more  "  unsaturated  "  acids  (linolic,  linolenic,  and  isolinolenic 
acids),  these  substances  greatly  predominating,  and  only  compara- 
tively small  amounts  of  olein  and  of  the  glycerides  of  the  solid 
fatty  acids  being  present,  so  that  these  latter  rarely  separate  in 
any  quantity  as  solid  "  stearines"  on  chilling  and  standing. 

Owing  to  the  more  or  less  considerable  amount  present  of 
these  unsaturated  constituents,  both  drying  and  semi-drying  oils 
possess  higher  iodine  absorbing  powers  than  the  oils  of  the  first 
four  classes,  and  develop  more  heat  on  mixture  with  sulphuric 
acid  (Maumene^s  test,  p.  147).  When  drying  oils  are  spread 
out  in  a  thin  layer  they  rapidly  absorb  oxygen  from  the  air, 
increasing  in  weight  and  "  drying  up  "  to  a  solid  varnish,  which 
in  time  becomes  perfectly  hard  and  not  in  the  least  sticky  or 
"tacky;"  semi-drying  oils,  similarly  treated,  increase  in  weight 
to  a  much  less  extent,  and  more  slowly,  and  never  dry  up 
thoroughly  to  a  hard  varnish  free  from  stickiness.  With  nitrous 
acid,  drying  oils  give  no  solid  elaidins ;  semi-drying  oils  usually 
give  buttery  masses  from  which  fluid  matter  separates. 

The  specific  gravity  of  drying  oils  is  usually  distinctly  higher 
than  that  of  oils  of  Class  I.,  generally  lying  between  '923  and 
•935,  and  increasing  as  oxidation  goes  011  until  finally  the  dried 
films  or  "  skins  "  are  heavier  than  water.  According  to  Bauer 
and  Hazura,  the  drying  qualities  are  the  more  pronounced  the 
larger  the  proportion  of  linolenic  and  isolinolenic  acids  present, 
linolic  acid  contributing  less  markedly  to  the  drying  properties  ; 
so  that  an  oil  consisting  mainly  of  the  glycerides  of  oleic  and 
linolic  acids,  even  when  the  latter  predominates,  does  not 
exhibit  drying  powers  equal  to  that  of  another  containing  a 
considerable  proportion  of  linolenic  and  isolinolenic  glycerides. 
They  regard  non-drying,  semi-drying,  and  drying  vegetable  oils 
as  distinguishable  by  the  following  characters  so  far  as  liquid 
constituents  are  concerned  : — 

Non-Drying  Oils  contain  none,  or  at  most  only  small  per- 
centages, of  the  glycerides  of  either  linolic,  linolenic,  or  isolin- 
olenic acids. 

Semi-Drying  Oils  contain  more  or  less  considerable  amounts 
of  linolic  glyceride,  but  little  or  no  glycerides  of  linolenic  or  iso- 
linolenic acid;  the  drying  action  being  also  retarded  by  the 
presence  of  more  or  less  olein  and  other  non-drying  glycerides. 

True  Drying  Oils  contain  considerable  amounts  of  linolenic 
and  isolinolenic  glycerides,  together  with  linolin,  and  but  small 
amounts  of  olein  and  non-drying  glycerides. 

Obviously  the  exact  lines  of  demarcation  between  non-drying 


DRYING   OILS.  291 

and  semi-drying  oils,  on  the  one  hand,  and  between  semi-drying 
and  truly  drying  oils,  on  the  other,  are  but  faintly  traced  j  so 
that  it  often  happens  that  a  given  oil  is  classed  by  one  writer 
amongst  the  oils  of  one  class,  and  by  another  amongst  those  of 
the  adjacent  class. 

As  regards  non-drying  and  semi-drying  animal  oils,  it  is 
noticeable  that  the  fatty  acids  thence  obtainable  yield  no  sativic 
acid  on  oxidation  by  alkaline  permanganate  (Benedikt  and 
Hazura) ;  from  which  it  results  that  linolic  acid  is  not  a  consti- 
tuent of  oils  of  this  class ;  whereas  larger  or  smaller  quantities 
of  sativic  acid  appear  to  be  obtainable  from  many,  if  not  all, 
vegetable  oils  by  this  treatment. 

The  best  known  drying  oils  are  the  following  : — 


Name  of  Oil. 

Source. 

Hemp  seed  oil, 
Lallemaiitia  oil, 
Linseed  oil, 
Poppy  seed  oil, 

Tobacco  seed  oil, 
Walnut  oil  (nut  oil), 
Weldseed  oil,  . 

Cannabis  saliva. 
Lallemantia  iberica. 
Linum  usitatissimum  (L.  perenne). 
Papaver  somniferum  ;  P.  rheas  ;  Glau- 
cium  luteum;  Argemone  mexicana. 
Nicotiana  tabacum. 
Juylans  regia. 
Reseda  luteola. 

Many  other  oils  of  pretty  strongly  marked  drying  qualities  are 
known  and  employed  locally,  without  being  articles  in  which  any 
considerable  amount  of  export  trade  is  done ;  few  of  these  have 
been  submitted  to  any  detailed  examination.  Hickory  nut  oil 
(Gary a  olivcrformis)  is  sometimes  sold  under  the  name  of 
"American  walnut  oil,"  but  appears  to  be  very  inferior  in  drying 
qualities.  The  seeds  of  Calopliyllum  inophyllum,  a  forest  tree 
widely  distributed  in  the  eastern  tropics,  furnish  an  oil  known 
by  various  names  (dilo,  domba,  pinnay,  poon  seed,  or  tamanu 
oil) ;  when  mixed  with  pigments,  this  forms  a  paint  that  dries  in 
1 2  hours,  without  any  previous  boiling ;  owing  to  the  large  yield 
of  oil,  and  the  plentifulness  of  the  tree  in  India,  Ceylon,  the 
Malay  Archipelago  and  Java,  and  the  South  Pacific  Islands,  &c., 
this  oil  appears  likely  to  be  an  important  article  in  future.  The 
kernels  of  the  Aleurites  cordata  (Elceococca  vernicia)  furnish  an  oil 
("Japanese  wood  oil,"  "  tung  oil")  largely  used  as  a  varnish  in 
China  and  Japan  on  account  of  its  extremely  rapid  drying 
qualities.  According  to  Cloez,  this  oil  contains  about  25  per 
cent,  of  olein,  and  75  of  a  homologue  of  linolin,  furnishing  on 
saponificatioii  elceomargaric  acid,  CirH30Oo//r  Further  investiga- 
tion is  desirable,  as  the  qualities  of  the  oil  are  such  as  to  render 
it  valuable. 

*  Ccmptes  rmdw,  83,  p.  943. 


292  OILS,    FATS,    WAXES,    ETC. 


CLASS  vii.— TRAIN,  LIVER,  AND  FISH  OILS. 

The  term  "  train  oil,"  strictly  speaking,  applies  to  any  oil 
extracted  from  the  blubber  of  cetaceans  and  allied  marine 
mammalia  (such  as  the  seal,  porpoise,  dolphin,  walrus,  &c.),  and, 
therefore,  in  the  widest  sense  includes  the  sperm  oil  class,  No.  X. ; 
but  in  the  present  connection  it  is  intended  to  apply  only  to 
those  blubber  oils  that  are  essentially  of  glyceridic  character,  and 
not  to  those  that  mainly  consist  of  compound  ethers  of  mono- 
hydric  alcohols.  It  is  not  quite  the  equivalent  of  the  German 
term  "thran,"  which  also  includes  fish  oils  (sardine  oil,  menhaden 
oil,  &c.)  as  well  as  liver  oils  (cod  liver  oil,  sunfish  liver  oil,  &c.) 

Oils  of  this  class  have  been  much  less  thoroughly  examined  as 
to  their  chemical  constitution  than  their  importance  as  trade 
products  warrants.     In  some  cases  they  consist  mainly  of  the 
glyceride  of  physetoleic  acid,  a  lower  homologue  of  oleic  acid  ;  but 
other  glycerides  are  generally  present  as  well,  preventing  the 
formation   of  solid  elaidins ;   soft  products   from    which   liquid 
matter  separates  on  standing  are  generally  formed,  much  as  with 
the  oils  of  Classes  II.  and  VI. ;  from  which  circumstance,  toge- 
ther with  the  high  iodine  number  generally  indicated,  and  the 
possession  of  some  degree  of  drying  qualities,  it  appears  probable 
that  drying  oil  glycerides  are  also  present.     Liver  oils  (cod  and 
shark's   livers,    &c.)   generally   contain  perceptible   amounts    of 
cholesterol  and  allied  biliary  products  ;  like  fish  oils  proper  (e.g., 
menhaden  oil),  they  evolve  large  amounts  of  heat  on  admixture 
with  sulphuric  acid,  resembling  the  vegetable  drying  oils  in  this 
respect;  whilst  train  oils  (whale  oil,  seal  oil,  &c.)  give  a  somewhat 
lower  degree  of  heat  evolution,  probably  on  account  of  the  presence 
of  notable  amounts  of  the  glycerides  of  solid  fatty  acids  (stearin, 
&c.)     When  oils  of  this  class  are  separated  from  the  nitrogenous 
tissues  immediately,  so  that  no  decomposition  takes  place,  they 
are    comparatively   inodorous    and    tasteless,    and    contain    no 
appreciable  quantity  of  free  fatty  acids  ;  but  if  the  livers,  blubber, 
fish,    &c.,    are   kept  for   any  length   of  time  before   the   oil  is 
extracted,  a  more  or  less  strongly  marked  animal  fishy  smell  is 
developed,  becoming  excessively  rank  in  extreme  cases  ;  as  in  the 
case  of  rancid  vegetable  oils,  more  or  less  hydrolysis  of  glycerides 
with  production  of  free  fatty  acids,  appears  to  accompany  the 
development  of  the  strong-smelling  bye  products  thus  formed. 

The  distinction  between  oils  of  this  class  (mainly  glyceridic  in 
character)  and  those  of  Class  X.  (mainly  non-glyceridic)  is  in 
actual  practice  not  extremely  sharply  marked  ;  for  sperm  oils 
usually  contain  small  quantities  of  glycerides,  although  the  chief 
constituents  are  non-glyceridic  compound  ethers ;  whilst  on  the 
other  hand,  some  of  the  blubber  oils  contain  notable  amounts  of 
solid  non-glyceridic  compound  ethers  (spermaceti),  deposited  on 


TRAIN    OILS. 


293 


cooling  and  standing.  In  fact,  it  is  as  difficult  or  impossible  to 
draw  a  hard  and  fast  line  of  demarcation  between  the  glyceridic 
and  non-glyceridic  animal  oils,  as  it  is  between  the  drying  and 
non-drying  vegetable  oils ;  and  for  the  same  reason,  viz.,  that 
whilst  the  two  extremes  are  tolerably  sharply  contrasted  in 
general  composition,  yet  various  intermediates  exist,  partaking 
of  the  character  of  both  classes.  To  some  extent,  this  may 
possibly  arise  from  the  circumstance,  that  when  a  ship  is  engaged 
in  oil-fishery,  it  is  not  always  practicable  to  keep  apart  the 
blubbers  obtained  from  different  species,  so  that  the  oil  ultimately 
extracted  is  often  a  mixture  of  the  products  obtained  from 
different  kinds  of  animal,  each  of  which,  if  examined  separately, 
would  exhibit  special  characteristics  analogous  to  those  dis- 
tinguishing different  seed  oils.  In  general,  it  appears  that 
whalebone-yielding  whales  *  (Balcenoidea]  furnish  oils  containing 
little  or  no  monohydric  compound  ethers  like  spermaceti ;  whilst 
toothed  whales  (Delphinoidea)  yield  oil  where  these  substances 
are  usually  present,  in  some  cases  as  chief  constituents ;  these 
latter  form  the  oils  of  Class  X. 

The  chief  oils  of  this  class  ate  the  following  : —    '        A 


Name  of  Oil. 


Sources. 


Train  Oils- 
Dolphin  and  Porpoise  oils, 


Seal  oils, 


Walrus  oil, 

(morse  oil,  dugong  oil, 
manatee  oil). 

Whale  oils  and  Blackfish 
oils. 


Delphinus  phoccena  (Phoccena  communis), 
or  common  porpoise.  P.  orca,  or  grampus. 
Delphinus  ddphis,  or  common  dolphin. 
Delphinus  globiceps.  D.tursio.  Monodon 
monoce.ros,  or  narwhal. 

Phoca  vttulina;  P.  groznlandica;  P.  barbata; 
P.annelata;  P.  lagura;  P.foetida;  P.  cas- 
pica ;  P.  proboscidea.  Otaria  jubata.  0. 
australis. 

Trichechus  rosmarus,  morse  or  walrus. 
lialicore  australis  and  //.  indicus,  or 
dugong.  Manatus  australis  and  M. 
>tmt.ricanus,  or  manatee. 

Baloznus  mysticetus  or  B.  grcenlandicus, 
the  "right  whale."  B.  glacialis,  or  polar 
whale.  B.  bb'ops,  or  humpbacked  whale. 
B.  antarctica,  or  cape  whale.  B.  australis, 
or  southern  black  whale.  Balcenoptera 
gibbar,  or  finner  whale.  Globiocephalus 
intermedias,  or  pilot  whale.  G.  macro- 
rhyncus,  or  killer.  Beluga  catodon,  or 
white  whale. 


*  Huxley  classes  the  existing  cetacea  (exclusive  of  extinct  genera)  as 
Balcenoidea  and  Delphinoidea,  the  latter  group  including  Platinistidce, 
Delphinidce  (dolphins,  porpoises,  grampus,  and  narwhal)  and  P/t.yseteridce  ; 
these  last  being  further  subdivided  into  Physeterina>  (cachelots  or  sperm 
whales)  and  Ilhyncoceti  (bottlenose  whales). 


294 


OILS,    FATS,    WAXES,    ETC. 


Name  of  Oil. 


Sources. 


Liver  Oils- 
Cod  oils, . 


Malabar  oils,  . 
Ray  and  Shark  oils, 


Fish  Oils- 
Herring  oils,    . 
(sardine,  sprat,  pilchard, 
anchovy,  louar,  &c. ) 


Menhaden  oil, 
Oolachan  oil,  . 
Tunny  oil, 


Gadus  morrhua(Asellus  major).  G.  cellarius. 

O.  molva  (Molva  vulgaris).    G.  (Kglefinus. 

G.  carbonarius  (Meriangus  carbonarius). 

G.  merlangus  (Merlangus  vulgaris). 

G.  pollachius  (Merlangus  pollachius). 

Merluccius  communis. 
Rhyncobatus  pectinata.      R.  Icevis.     Galio- 

cerda  tigrina.      Carcharias  melanopterus. 
Raja  clavata.    R.  batis.     Trigon  pastinaca. 

Squalus   carckarias,    or    common   shark. 

S.  maxima,  or  basking  shark.    S.  glacialis, 

or  Greenland  shark.    S.  zygcena  (Zygcena 

malleus),  or  hammerfish.    S.  acanthius,  or 

picked  dogfish.    S.  spinax  niger,  or  kulp. 

Clupcea  pontica  (Astrakan  herring). 

O.  sardinus,  or  sardine  ;    C.  neohouri,  C. 

lemuru,  and    C.  palasah,   or  Indian  and 

Malayan   louar.      C.    sprattus,    or   sprat. 

C.   pilchardus,   or    pilchard.       Engraulis 

encrasicholus,  or  anchovy. 
Alosa  menhaden  (Brevoordia  menhaden). 
Thaleichthys  paciferus  osmerus. 
Thynnus  vulgaris. 


Schadler  gives  the  following  table  of  colour  reactions  of  seal, 
whale,  liver,  and  fish  oils  with  strong  nitric  acid  (sp.  gr.  1*45); 
sulphuric  acid  (sp.  gr.  1/6— 1 '7) ;  and  the  two  mixed  in  equal  pro- 
portions (compare  p.  153). 


Nitric  Acid. 


Sulphuric  Acid. 


Mixed  Acids. 


SEAL  OIL— 
Red  brown, 


WHALE  OIL— 
Brownish,  becoming 
full     brown,     and 
finally  black  brown. 

LIVER  OILS — 
Blood  red,  becoming 
brownish    red    to 
brown. 

FISH  OILS— 
Brown,   . 


Reddish  yellow,  becoming 
reddish  brown,  and  ul- 
timately brownish  red, 
somewhat  like  blood. 

Brown,  becoming  black 
brown. 


Violet  to  black  violet. 


At  first  greenish,  then 
brown,  and  finally  quite 
black. 


Reddish,   becoming 
brown. 


Yellow,  becoming 
reddish,  and  finally 
dirty  brown. 


Yellow  red, becoming 
bright  red,  finally 
reddish  brown  with 
violet  streak. 

Yellow,  then  greenish, 
afterwards  brown. 


VEGETABLE  BUTTERS,  ETC. 


295 


CLASS  VIII.— VEGETABLE  BUTTERS,  FATS  AND 
WAXES,  &c. 

When  the  proportion  of  glycerides  of  relatively  high  melting 
point  to  olein  is  large,  the  physical  texture  of  a  substance  that 
would  be  an  oil  in  the  tropics  becomes  more  like  that  of  butter 
at  15°-20°;  concurrently  with  the  change  in  comparative  fluidity 
the  iodine  absorption  is  largely  reduced  as  compared  with  oils 
of  Classes  I.  and  VI.,  on  account  of  the  diminished  proportion 
of  olein  present.  In  the  case  of  certain  vegetable  glyceridic 
waxes  (e.g.,  Japanese  wax),  the  olein  is  reduced  to  insignificant 
proportions  or  to  nil,  with  the  result  of  increasing  the  relative 
solidity  and  considerably  raising  the  melting  point.  Some  of  the 
substances  of  this  class  contain  a  notable  proportion  of  glycerides 
of  acids  of  the  acetic  family  of  sufficiently  low  molecular  weight 
to  be  readily  volatile  with  steam  at  ordinary  pressure  (e.g.,  coker- 
nut  and  laurel  butters  and  palm  kernel  fat) ;  others  are  practically 
destitute  of  such  ingredients.  When  subjected  to  regulated 
pressure  (p.  283)  liquid  oleines  are  squeezed  out,  and  solid 
stearines  left,  the  former  closely  resembling  oils  of  Classes  I. 
and  VI.  when  sufficiently  freed  from  the  latter. 

The  best  known  substances  of  this  class  are  the  following : — 


Name  of  Butter,  &c. 


Bassia  fat;  HUpe*  butter, 
Mahwa  butter,  Phulwara 
fat  (Fulwa  fat),  Shea  but- 
ter (Galam  butter),  &c. 

Cacao  butter,    . 


Chinese  tallow, 
Cokernut     butter     (copra 
butter  or  copra  fat). 
Cotton  seed  stearine, 
Dika  fat,  .... 

Japanese  wax,  . 


Malabar    tallow    (Piney- 

tallow). 
Myrtle  wax, 

Myristica  butters  ( Xutrneg 
butter,  Virola  tallow, 
Otaba  wax,  Deuba  or 
ocuba  wax,  &c. ) 

Palm  butter  (palm  oil). 

Palmmit     butter    (palm 
kernel  oil). 


Sources. 


Bassia  lalifolia  (Roxb. )  B.  longifolia(L\aja.. ) 
B.  butyracea.  B.  Parkii  (Butyrosperma 
Parkii — Kotschy). 

Theobroma  cacao  (Linn. )  T.  bicolor  (Humb. ) 
T.  aufjustifolium  (Sesse).  T.  leiocarpium 
and  T.  pentagonum  (Bern. )  T.  microcar- 
pium  (Mart.) 

Stillingia  sebifera  (Croton  sebiferum,Lmn.) 

Cocos  nucifera;  C.  butyracea, 

Cotton  seed  oil  by  chilling  and  pressing. 
Irvingia  barteri  (Hock.)    Mangifera  gabo- 

nensis  (Aubry  Le  Comte). 
Rhus   succedanea    (Linn.);    E.    acuminata 

(De  C.);  2t.  vernidfera  (De  C.);  R.juglan- 

difolia  (Don).     It.  sylvestris  (Siebold). 
Vateria    indica    (Linn.)  ;     V-    malabarica 

(Blum.);  JSlaeocarpus  copaliferus  (Retz.) 
Myrica  cerifera,  and  several  other  species 

of  myrtle. 
Myristica  officinalis  (Linn.);  M.  moscliata 

(Thumb.);    M.  sebifera  (Virola  sebifera)', 

M.  otoba  (Humb.  and  B.);   M.  ocuba  (M. 

ucuba,  M.  bicuhyba);  M.  malabarica. 

Elais  fjuineensis  (Jacq.)  ;  E.  melanococca 
(Gaert.);  Alfonsia  oleifera  (Humb.) 


296  OILS,    FATS,    WAXES,    ETC. 

Similar  solid  or  semisolid  vegetable  fats  are  also  furnished  by  the 
following  trees  and  plants  : — 

Nephelium  lappaceum  (Linn.) ;  indigenous  to  Sunda  Island, 
Malacca,  and  some  parts  of  China.  The  seeds  furnish  "  Ram- 
butan  tallow,"  melting  at  about  65°,  the  solid  stearine  of  which 
is  chiefly  the  glyceride  of  arachic  acid;  a  little  olein  is  also 
present  (Oudemanns). 

Carapa  guyanensis  (C.  guineensis)  and  C.  indica  (or  C.  moluc- 
censis) ;  found  in  Brazil,  Guiana,  Cruinea,  Sierra  Leone,  India, 
Ceylon,  &c.  The  seeds  of  these  two  species  furnish  "  Carapa  fat  " 
(otherwise  designated  "  Andiroba  fat,"  "Coundi  oil,"  "  Crabwood 
oil,"  "  Touloucoona  oil,"  &c.),  possessing  a  composition  akin  to 
that  of  palm  oil — i.e.,  consisting  chiefly  of  the  glycerides  of 
palmitic  and  oleic  acid.  It  usually  possesses  a  sickly  persistent 
odour  almost  impossible  to  get  rid  of.  The  coloured  natives  use 
it  largely  as  an  unguent  and  insectifuge  for  the  head,  its  pro- 
perties  in  this  respect  being  apparently  due  to  an  admixed  bitter 
principle  termed  carapin. 

Mafureira  oleifera  (Bert.)  or  Trichelia  emetica  (Vahl.)  This 
tree  grows  in  Mozambique,  and  about  Zambesi  and  the  White 
Nile  ;  by  crushing  the  seeds  and  boiling  with  water  a  fat  known 
as  "  Mafura  tallow  "  is  obtained,  much  resembling  cacao  butter, 
melting  at  42°,  and  chiefly  consisting  of  palmitin  and  olein. 

Calophyllum  inophyllum  (Linn.),  indigenous  to  India  and  the 
Malay  Archipelago,  and  C.  calaba,  found  in  the  Antilles,  yield 
respectively  "Poona  fat"  ("  poon  seed  oil  ")  or  "Tacamahac  fat") 
and  "  Calabar  oil."  The  former  is  also  known  by  various  other 
names  (vide  p.  291). 

Laurus  nobilis,  found  largely  in  Southern  Europe  and  Asia, 
yields  "laurel  butter"  ("bayberry  fat"),  largely  consisting  of 
the  glyceride  of  lauric  acid,  along  with  a  little  myristin  and 
other  homologues,  and  some  olein.  A  similar  product  is  obtained 
from  L.  persea  (Linn.)  or  Persea  gratissima  (Gaert.),  the  Alligator 
pear  tree  of  Brazil  and  the  West  Indies  ;  known  as  "  Alligator 
pear  oil,"  " Persea  fat,"  and  "Avocado  oil." 

In  addition  to  these,  a  large  number  of  more  or  less  hard 
vegetable  fats  and  tallows  are  obtainable  from  other  sources, 
concerning  the  chemical  constitution  of  which  little  or  nothing 
is  known  •  thus  "  Malayan  tallow  "  and  "  Borneo  tallow "  are 
solid  fats  obtained  from  the  nuts  of  various  species  of  Hopea  in 
Java,  Sumatra,  and  Borneo.  An  analogous  product,  "Sierra 
Leone  butter,"  is  obtained  in  Sierra  Leone  from  Pentadesma 
butyracea.  "  Goa  butter"  ("Kokum  butter"  or  "  Mangosteen 
oil ")  is  a  similar  fat  obtained  in  the  East  Indies  from  the  seeds 
of  Garcinia  indica  (Mangosteena  indica).  The  allied  species 
G.  pictoria  or  gamboge  tree  furnishes  "gamboge  butter."  The 
seeds  of  Pongamia  glabra,  another  East  Indian  shrub,  furnish 
"  Korinje  (Karanja)  butter,"  "  Poondi  oil "  or  "  Ponga  oil,"  some- 


LESSER    KNOWN    VEGETABLE    FATS.  297 

what  more  readily  fusible  than  most  of  the  vegetable  fats  and 
tallows.  "  Macaja  butter  "  is  derived  from  the  edible  fruit  of 
Cocos  aculeata  (Acromia  sclerocarpa,  Mart.;  Bactris  minor,  Gaert.), 
indigenous  to  Brazil,  Guiana,  and  the  WTest  Indies.  In  Java  a 
fat  much  resembling  coker  butter,  "  tangkallak  fat,"  is  derived 
from  the  Cylicodaphne  sebifera.  Semisolid  fats  are  obtained 
from  the  Canarium  commune  of  the  Moluccas  and  Malabar 
("  Canary  oil,"  "Java  almond  oil  ")  and  the  butternut  tree  of  the 
Brazils  (Rhizobolus  butyrosa;  the  allied  species,  R.  amygdalifera 
(Caryocar  brasiliensis)  and  Caryocar  tomentosum,  respectively 
furnish  "  Caryocar  oil "  and  "  Sawarri  (or  Souari)  nut  butter." 
The  soap  tree  of  Bengal,  Southern  India,  and  the  West  Indies 
(Sapindus  emarginatus,  Roxb.;  S.  trifoliatus,  Linn.;  S.laurifolia, 
Vahl.),  furnishes  a  fruit  rich  in  saponin,  and  also  yielding  a  semi- 
solid  fat.  "  Maccassar  oil "  is  a  semisolid  fat  obtained  from  the 
seeds  of  Sckleicliera  trijuga ;*  and  "Piquia  oil"  ("Pekea  fat") 
is  a  similar  product  from  Pekea  butyrosa  and  P.  ternatea,  found 
in  Guiana  and  the  Antilles.  Melia  azedarach  (Linn.),  the  "pater- 
noster tree  "  of  Syria,  Northern  India,  and  the  Deccan,  <kc.  (so- 
called  from  the  employment  of  its  stones  in  Italy  and  elsewhere 
for  making  rosaries),  also  known  as  Melia  indica  (Brand.)  and 
Azadirachta  indica  (Juss.),  furnishes  a  very  similar  semisolid  fat, 
known  as  "  Zedrach  oil,"  "  Margosa  oil,"  "  Veppam  fat,"  or 
"  Nimb  (or  Neem)  oil."  "  Niam  fat "  is  derived  from  the 
Lophira  alata,  found  in  Eastern  and  Western  Africa.  "  Chaul- 
moogra  oil"  is  a  soft  fat  fusing  at  about  17°C.,  obtained  from 
the  seeds  of  Gynocardia  odorata  (Cliaulmoogra  odorata),  much 
used  in  India,  China,  and  elsewhere  for  medicinal  application  to 
the  skin.  "Soudan  butter"  is  a  soft  fat  obtained  by  boiling 
with  water  the  seeds  of  Vitellaria  paradoxa,  or  Soudanese  butter 
plant ;  a  similar  product  is  obtained  in  Cochin  China  and  Japan 
from  the  seeds  of  Sebifera  glutinosa  (Tetrantliera  laurifolia,  Jacq.) 
The  seeds  of  (Enocarpus  bacaba  and  CE.  patawa,  of  Central 
America,  yield  by  similar  treatment  a  soft  fat  known  locally  as 
"Comou  butter."  "Para  butter"  or  "Assai  oil"  is  similarly 
obtained  from  the  Assai  palm  (Euterpe  oleracea],  common  in 
Brazil  and  the  neighbourhood  of  Para.  "Chequito"  is  a  fatty 
substance  obtained  by  the  Kaffirs  of  Southeast  Africa  from  the 
"butter  tree,"  Combretum  butyraceum.  The  seeds  of  Cocculus 
indicus  contain  a  solid  fat,  extracted  and  used  by  the  natives  in 
India,  but  apparently  not  yet  known  commercially  ;  similar  pro- 
ducts are  obtained  from  the  fruit  kernels  of  Lucuma  bonj)landi 
in  Mexico,  and  the  Ochoco  (Dryobalanops)  of  Guinea. 

*  Also  from  the  oleaginous  fruit  of  Stadmannia  (Cupania)  Sideroxylon, 
growing  in  Sunda  and  Timor  Islands,  and  from  the  seeds  of  the  safflower 
(Oarthamus  tinctorins) ;  other  varieties  of  socalled  "Macassor"  oil  are 
simply  more  or  less  fluid  oils  in  which  odorous  flowers,  &c.,  have  been 
digested  so  as  to  scent  them. 


CFTHE 


298  OILS,    FATS,    WAXES,    ETC. 

In  addition  to  the  above,  a  large  number  of  other  sources  of 
vegetable  fats  exist  in  different  parts  of  the  world,  the  knowledge 
of  which  is  as  yet  chiefly  confined  to  the  natives ;  there  can, 
however,  be  little  doubt  that  in  due  time,  as  civilisation  advances 
and  opportunities  for  export  and  manufacture  become  more 
frequent,  many  of  these  little-known  products  will  be  found  to 
be  of  considerable  value  as  sources  of  oleaginous  material. 


CLASS  IX.— ANIMAL  FATS— TALLOW,  LAUD,  AND 
BUTTER   CLASS. 

Almost  every  known  animal  is  capable  of  yielding  more  or  less 
considerable  amounts  of  fatty  matter  by  appropriate  treatment ; 
but  in  practice,  comparatively  few  are  actually  employed  as 
sources  of  fat,  apart  from  their  consumption  as  food.  The  solid 
fat  of  oxen  and  sheep  (known  as  tallow  or  suet  when  derived  from 
the  adipose  tissues  of  the  body),  the  grease  extracted  from  their 
hoofs  (neat's  foot  oil,  sheep's  trotter  oil),  and  that  obtained  by 
boiling  the  bones  (bone  grease)  are  closely  akin  in  general 
composition,  except  that  the  latter  are  softer  in  character,  chiefly 
because  containing  a  larger  proportion  of  olein,  and  a  smaller 
amount  of  solid  glycerides.  The  fatty  matters  (butters)  contained 
in  the  milk  of  cows  and  ewes,  on  the  other  hand,  have  a  composi- 
tion materially  different  from  that  of  the  fats  present  in  the 
adipose  tissues  of  the  body ;  and  the  same  remark  applies  to  the 
milk  fats  of  all  other  mammalia,  so  far  as  they  have  been 
examined.  In  general,  the  milk  fats  of  various  animals  do  not 
differ  very  greatly  in  character ;  thus,  the  butters  derived  from 
the  cow,  ass,  ewe,  goat,  elephant,  hippopotamus,  sow,  mare,  and 
woman,  appear  to  be  as  closely  akin  as  are  the  more  or  less  solid 
tallows,  greases,  and  suets  obtainable  from  the  body  tissues  of 
these  various  animals ;  but  whilst  the  latter  fats  are  all  essentially 
mixtures  of  the  liquid  glyceride  of  oleic  acid,  and  the  solid 
glycerides  of  stearic  and  palmitic  acids  (the  liquid  constituents 
being  present  in  larger  quantity  in  the  softer  fats,  like  lard),  the 
former  fats  contain  a  considerable  amount  of  the  glycerides  of 
acids,  also  of  the  stearic  series,  but  of  much  lower  molecular 
weight  than  palmitic  acid.  Similarly,  the  milk  fat  of  the  whale 
is  not  widely  different  from  that  of  the  cow,  although  the  oil  of 
whales'  blubber  differs  much  from  suet  in  composition. 

The  fats  obtained  from  the  carcases  of  birds  (goose  grease, 
turkey  fat,  pheasant  grease,  &c.)  appear  to  be  substantially 
similar  to  the  softer  body  fats  of  mammalia  in  general  composi- 
tion, essentially  consisting  of  olein,  with  enough  stearin  and 
palmitin  to  render  them  semisolid  at  the  ordinary  temperature ; 
the  oleaginous  matter  contained  in  eggs  (e.g.,  hen's  eggs)  is  softer 


ANIMAL   FATS    AND    OILS. 


299 


still,  and  consists  of  olein  and  palmitin,  together  with  other 
substances  foreign  to  the  oil  proper  (vide  p.  121). 

Various  reptiles  (turtles,  crocodiles,  &c.)  are  utilised  in  different 
parts  of  the  world  as  sources  of  oleaginous  matters,  apparently, 
for  the  most  part,  closely  akin  to  the  fats  of  the  mammalian 
vertebrates ;  on  the  other  hand,  the  oily  matters  derived  from 
fish  are  differently  constituted  (supra,  p.  292). 

The  following  list  includes  the  more  important  solid  or  semi- 
solid  animal  fats,  apart  from  those  derived  from  fishes  and 
cetacea : — 


Name  of  Fat. 


Sources. 


Bone  fat,       .... 

Butter  (cow's  milk  fat), 
Butter  substitutes  (butterine, 
margarine,  oleomargarine), 

Crocodile  fat  (alligator  fat), . 

Egg  oil, 
Goose  grease, 
Horse  grease  (mare's  grease) 
Lard,    .... 
Tallow, 

Tannery  grease,  kitchen  grease, 
wool  grease, 


Bones  of  oxen  and  horses,  &c.,  extracted 

by  boiling  or  by  solvents. 
Domestic  cow. 
The  softer  portions  of  the  fat  of  oxen 

and  sheep,  &c.,  separated  by  special 

processes. 
Indian  crocodile  and  common  alligator 

(Alligator  Iticius). 

Yolks  of  hen's  eggs  (Gallus  domesticus). 
Common  goose. 

Horse  carcases  (Equus  caballus}. 
Common  hog. 
Ox,  sheep,  goat,  &c. 
Animal  greases  from  various  kinds  of 

trade  refuse. 


In  addition  to  these,  the  fat  of  the  alpaca  is  used  to  a  con- 
siderable extent  in  some  parts  of  South  America;  that  of  the 
dog  in  continental  Europe,  that  of  the  hippopotamus  in  Africa,  and 
that  of  the  turtle  in  the  islands  "of  the  South  Pacific,  Brazil,  and 
along  the  South  American  coast.  The  last  is  sufficiently  fluid  in 
a  tropical  or  subtropical  climate  to  be  used  as  a  burning  oil. 
Bear's  grease  was  at  one  time  highly  esteemed  as  a  pomade,  but 
is  now  mostly  superseded  by  other  forms  of  clarified  fat.  Many 
other  animal  fats  are  also  used  locally  in  different  countries  to  a 
greater  or  lesser  extent,  but  as  yet  are  not  articles  of  regular 
trade.  When  the  solid  or  semisolid  fats  of  this  class  are 
subjected  to  expression,  the  liquid  animal  oleines  of  Class  IV. 
result — e.g.,  lard  oil,  tallow  oil,  &c. 


CLASS  X.— ANIMAL  OILS— SPERM  OIL  CLASS. 

The  blubber  oils  included  in  Class  VII.  (whale,  seal,  porpoise, 
<fec.)  differ  from  those  belonging  to  this  class  essentially  in  that  they 
consist  chiefly  of  fatty  glycerides ;  whereas  the  oils  now  under 
consideration,  whilst  not  invariably  free  from  glyceridic  con- 


300  OILS,    FATS,    WAXES,    ETC. 

stituents,  have,  as  regards  their  leading  constituents,  an  entirely 
different  composition,  these  substances  being  compound  ethers 
formed  from  monohydric  alcohols  and  fatty  acids,  analogous  to 
ethyl  acetate  and  similar  substances.  In  general,  two  kinds  of 
such  compound  ethers  appear  to  be  present  simultaneously — one 
liquid  at  ordinary  temperatures,  corresponding  with  the  olein  of 
ordinary  vegetable  oils,  and  consisting  of  ethers  of  acids  of  the 
oleic  family ;  the  other  solid,  corresponding  with  stearin  or 
palmitin.  and  consisting  of  ethers  of  acids  of  the  acetic  family. 
Just  as  a  vegetable  oil  on  chilling  deposits  solid  matter  of  the 
stearin  character,  readily  separable  by  filtration  or  straining,  so 
does  a  blubber  oil  of  the  sperm  class  similarly  deposit  solid 
crystallisable  matter,  generally  the  substance  known  as  spermaceti 
(mainly  consisting  of  cetyl  palmitate);  the  liquid  portions 
separated  from  this  deposit  appear  to  be  mixtures  not  only  of 
compound  ethers  of  different  homologous  acids,  but  also  of 
different  homologous  alcohols,  some  of  which  belong  to  the  ethylic 
series,  whilst  others  are  apparently  homologues  of  acrylic  alcohol, 
capable  of  combining  with  iodine,  like  the  unsaturated  acids.  In 
consequence,  when  saponified,  these  liquid  oils  yield  large 
percentages  of  products  insoluble  in  water,  but  soluble  in  ether, 
«fec.,  consisting  of  mixtures  of  the  alcohols  formed  during  saponi- 
fication  ;  a  circumstance  sharply  distinguishing  them  from  the 
glyceridic  oils  of  Class  VII.,  which  yield  only  comparatively 
small  quantities  of  unsaponifiable  matters  insoluble  in  water, 
chiefly  consisting  of  cholesterol  and  similar  substances. 

On  account  of  the  presence  of  compound  ethers  of  the  oleic 
family,  oils  of  the  sperm  class  become  more  or  less  solidified  by 
nitrous  acid  in  virtue  of  the  elaidin  reaction ;  with  Maumene's 
test  (p.  147)  they  develop  but  little  more  heat  than  olive  oil, 
being  thus  sharply  distinguished  from  most  fish  oils  of  Class  VII., 
which  give  a  much  greater  heat  evolution  (pp.  149,  150).  Their 
peculiar  compound  ether  composition  largely  raises  the  saponifi- 
cation  equivalent. 

The  physical  characters  of  this  class  of  oils  also  are  peculiar  in 
virtue  of  their  unusual  constitution  ;  thus  their  efflux  viscosity 
(p.  101)  is  much  less  influenced  by  variation  of  temperature  than 
is  the  case  with  most  other  oils,  whence  their  value  as  lubricants 
for  special  purposes.  Their  specific  gravity  is  low,  usually  con- 
siderably below  -900,  near  -880. 

The  principal  oils  of  this  class  are  as  follows  : — 


Name  of  Oil. 


Sources. 


Sperm  oil,     . 

Doegling  oil   (Arctic   sperm 
oil  or  true  bottlenose  oil), 


Physeter    macrocephalus,    L.    (Cachelot 

whale). 
Hypeioodon  rostratus  (Balcena  rostrata), 

or  true  bottlenose  whale,  H.  Bid  ens. 


WAXES.  301 

Various  other  toothed  cetaceans  also  furnish  oils  containing 
spermaceti  in  sufficient  quantity  to  separate  out  in  the  solid 
state  on  chilling  and  standing,  more  especially  the  oil  from  the 
bottlenose  dolphin,  Delphinus  globiceps,  which  appears  to  be 
essentially  intermediate  in  character  between  the  almost  wholly 
glyceridic  and  largely  valerin-containing  oil  from  the  common 
porpoise,  and  the  mainly  compound  ethereal  sperm  oil  of  the 
cachelot  in  which  only  small  amounts  of  valerin  are  present. 


CLASS  XI.— VEGETABLE  NONGLYCERIDIC  WAXES. 

Several  species  of  plants  are  known,  the  berries,  leaves,  stalks, 
<fec.,  of  which  are  naturally  covered  with  a  waxy  exudation  closely 
akin  in  its  origin  to  certain  of  the  more  solid  vegetable  fats,  but 
differing  therefrom  in  being  essentially  nonglyceridic  in  character. 
Of  these  substances  the  principal  are  as  follows  : — 


Name  of  Wax. 

Source. 

Carnauba  wax, 
Cowtree  wax, 

Corypha    cerifera    (Linn.);    Copernicia 
cerifera  (Mart.) 
Galactodendron      americaum      (Linn.); 
(G.  utile,  Kunth  ;    Brosimum  galacto- 
dendron,  Don.) 

In  addition  very  similar  products  are  obtained  from  several 
other  sources — e.g.,  Petha  wax,  from  the  bloom  on  the  Indian 
white  gourd  (Benincasa  cerifera) ;  Fig  wax  (Getah  wax),  pre- 
pared in  Java  and  Sumatra  from  Ficus  umbellata  and  F.  cerifera 
(Blume) ;  Palm  ivax  (Ceroxylin),  largely  used  in  Brazil,  from  the 
common  wax  palm,  Ceroxylon  andicola  (Humb.),  and  the  Klop- 
stock  palm,  Klopstockia  cerifera  (Karsten) ;  and  Cordillera  wax 
from  the  Cordillera  waxtree  (Elceagia  utilis. 

These  products,  however,  do  not  seem  to  have  been  submitted 
as  yet  to  full  chemical  investigation,  so  that  it  is  not  certain 
whether  they  are  true  vegetable  waxes  of  nonglyceridic  character, 
or  simply  vegetable  fats  of  waxy  texture  analogous  to  socalled 
Japanese  wax.  Comparatively  little  of  these  various  kinds 
of  vegetable  waxes  is  as  yet  exported  to  Europe,  most  being 
used  for  candlemaking,  &c.,  in  the  countries  where  they  are 
indigenous. 


CLASS  XII.— BEESWAX  AND  SPERMACETI  CLASS. 

The  nonglyceridic  waxlike  compound  ethers  of  animal  origin 
used  to  any  extent  industrially  are  but  few  in  number,  the  prin- 
cipal being  as  follows  : — 


302 


OILS,    FATS,    WAXES,    ETC. 


Name  of  Wax. 


Beeswax  (ordinary  beeswax. 
Andaquia  wax,  Antilles  wax, 
African  beeswax,  Abyssinian 
beeswax,  &c.), 


Chinese  wax  (Peh-la  or  Pela), 
Indian  wax  (Arjun  wax), 
Niin  fat,       .... 
Spermaceti,  .... 
Woolgrease, 


Source. 


Apis  meUifera,  or  common  bee.  Numer- 
ous allied  species  exist,  many  of  which 
are  also  wax  producers — e.g.,  Apis 
fasciata  (Melipona  fasciata),  or  South 
American  bee  ;  Apis  unicolor,  or  Mada- 
gascan  bee ;  Apis  dorsata,  of  the  Eastern 
Archipelago.  The  common  wasp  and 
other  allied  genera  are  also  wax  pro- 
ducers to  a  limited  extent. 
j  Coccus  sinensis  (Coccus pe-la,  C.chinensis} 

Ceroplastes  ceriferus. 

Coccus  adipofera. 

Physeter  macrocephalus. 

Natural  grease  (inspissated  perspiration) 
of  the  common  sheep. 


CHAPTER  XIY. 
PRINCIPAL  USES  OF  OILS  AND  FATS,  &c. 

THE  classification  described  in  the  previous  chapter  is  mainly 
based  on  the  physical  and  chemical  characters  of  the  natural  fixed 
oils  and  allied  substances  ;  from  the  point  of  view  of  their  leadiDg 
practical  uses  they  may  be  conveniently  considered  under  one  or 
other  of  the  following  six  heads  : — 

1.  Substances  used  for  edible  purposes,  including  cooking  and 
preservation  of  food  (e.g.,  sardines). 

2.  Fluid  oils  employed  for  burning  in  lamps  or  otherwise. 

3.  Substances  furnishing  solid  materials  for  candlernaking. 

4.  Substances  used  in  the  manufacture  of  soap. 

5.  Drying  oils  employed  for  paint  manufacture  and  in  the  pre-. 
paration  of  varnishes,  linoleum,  and  such  like  products. 

6.  Substances  used  for  miscellaneous  purposes ;  more  especially 
as  lubricants  or  ingredients  in  lubricating  mixtures ;  for  currying 
leather,  dressing  cloth  and  textile  fabrics,  and  similar  purposes ; 
as  oil  baths  for  tempering  metals  ;  as  solvents  for  odorous  matters 
in  the  process  of  enfleurage  in  perfumery  manufacture ;  for  the 
preparation  of  unguents,  pomades,  cosmetics,  &c. ;  in  the  manu- 
facture   of  sealing  wax   and   analogous   compositions ;    and  for, 
numerous  minor  uses  in  the  arts  generally. 

Of  these  six  groups,  Nos.  3  and  4  are  separately  considered  in 
§  6  and  §  7  (candle  and  soapmaking,  including  glycerol  extrac- 
tion) ;  with  respect  to  the  other  uses,  some  few  points  are  of 
special  interest  from  the  technological  point  of  view,  in  connection 
with  which  the  question  of  purity  and  freedom  from  adulteration 
with  inferior  materials  is  frequently  of  prime  importance. 


EDIBLE    OILS    AND    FATS.  303 

EDIBLE  AND  CULINARY  USES  OF  OILS, 
FATS,  «fec. 

Fatty  matters  of  various  kinds  are  ingredients  in  most  kinds 
of  food  stuffs  in  common  use  to  a  greater  or  lesser  extent ;  thus 
apart  from  suet  and  the  adipose  tissues  interleaved  with  the 
"  lean  "  of  most  kinds  of  animal  meat,  most  vegetable  seeds,  nuts, 
and  other  edible  produce  contain  more  or  less  considerable 
quantities  of  oleaginous  matter ;  sometimes  to  an  extent  suffi- 
ciently large  to  admit  of  oil  being  extracted  by  pressure  fy.g.t 
olives,  walnuts,  hazelnuts,  &c.),  sometimes  only  in  smaller  quan- 
tity, so  that  a  solvent  (ether,  Ac.)  is  requisite  before  the  presence 
of  oil  can  be  demonstrated.  When  thus  treated,  however,  even 
such  substances  as  wheaten  flour  and  cereal  produce  generally, 
rice,  and  dried  vegetables  can  be  shown  to  contain  small  quan- 
tities of  oleaginous  ingredients. 

Apart  from  the  consumption  of  oily  matter  for  food  in  forms 
such  as  these,  large  quantities  of  separately  extracted  fatty  sub- 
stances are  habitually  used  as  edibles  by  both  civilised  and 
uncivilised  races — e.g.,  "  salad  "  oils  employed  for  "  dressing  "  raw 
vegetables  and  otherwise  as  food  materials ;  more  or  less  purified 
and  rendered  animal  fats,  especially  dripping  and  lard ;  and  the 
fatty  matter  of  cow's  milk  (butter).  In  cold  climates  seal  and 
whale  oil  are  eagerly  partaken  of  by  the  natives  as  heat-generating 
foods,  whilst  a  lump  of  tallow  is  a  delicacy ;  elsewhere  fish  pre- 
served in  oil  (e.g.,  sardines),  or  cooked  in  hot  oil,  pastry  containing 
butter,  suet  puddings,  and  numberless  other  viands  into  the  com- 
position of  which  more  or  less  oleaginous  matter  enters,  are- 
everyday  articles  of  diet. 

With  the  exception  of  actively  medicinal  oils  (such  as  croton  and 
castor  oils),  the  great  bulk  of  natural  glycerides  are  suitable  as 
food  material  for  cattle,  especially  when  used  without  separation 
from  the  other  vegetable  matters  naturally  accompanying  them. 
Linseed  cake  (crushed  linseed  subjected  to  pressure  so  as  to 
express  most  of  the  oil),  and  similar  substances  from  other  kinds  of 
seeds,  &c.,  are  well  known  cattle  foods,  the  value  of  which  largely 
depends  on  the  amount  of  residual  oily  matter  left  in  the  mass. 

Waxes,  on  the  other  hand,  are  but  little  adapted  for  nutritive 
purposes ;  thus  beeswax  (even  when  eaten  along  with  honey) 
mostly  passes  unchanged  through  the  alimentary  canal,  and  is  not 
assimilated  at  all,  either  by  human  beings  or  other  mammalia. 

In  the  preparation  for  table  and  culinary  use  of  oils  and  fatsr 
&c.,  but  little  treatment  of  a  technical  nature  is  usually  requisite, 
the  chief  points  requiring  attention  being  good  quality  of  the 
raw  material,  and  cleanliness  in  the  treatment  to  which  it  is 
subjected  ;  thus  the  excellence  of  the  butter  prepared  in  a  given 
dairy  chiefly  depends  on  the  quality  of  the  milk  from  which  it  is. 
separated,  and  the  care  and  cleanliness  employed  throughout  the 


304  OILS,    FATS,    WAXES,    ETC. 

process.  Very  similar  remarks  apply  to  the  preparation  of  the 
finer  qualities  of  refined  lard  intended  for  food,  and  the  ordin- 
ary kitchen  operations  of  clarifying  dripping,  &c.,  and  to  the 
extraction  of  vegetable  oils  generally.  As  already  described, 
"virgin"  oils,  and  "first  runnings"  are  generally  prepared  from 
choice  oil  sources  (olives,  arachis  nuts,  &c.)  by  gentle  pressure 
without  heat,  somewhat  coarser  grades  being  subsequently  ex- 
pressed by  stronger  pressure  and  heat  combined;  refining  by 
agitation  with  water,  subsidence,  and  straining,  being  usually 
preferred  to  processes  involving  chemical  treatment.  In  some 
parts  of  Russia  and  Eastern  Europe  much  coarser  oils  are  con- 
sumed by  the  peasantry  than  are  usually  similarly  employed 
amongst  either  Western  Nations  or  Asiatics ;  hempseed,  poppy 
seed,  and  linseed  oils,  often  somewhat  crudely  extracted,  being 
largely  used  as  cooking  oils.  |  Of  late  years,  however,  sunflower 
seed  oil  has  to  a  great  extent  superseded  these  coarser  oils  ;  whilst 
in  Western  Europe,  America,  and  many  other  parts  of  the  world, 
cotton  seed  oil,  expressed  by  the  hydraulic  process  described 
in  Chap,  ix.,  and  subsequently  refined  by  boiling  with  alkalies, 
ifec.,  is  now  very  largely  employed  for  many  purposes  for  which 
formerly  only  olive  oil  was  used,  or  the  better  grades  of  arachis 
oil,  sesame  oil,  and  similar  high-class  substances ;  the  result  of 
properly  refining  a  fair  quality  of  raw  cotton  seed  oil  being  to 
produce  a  light  coloured  pleasantly  tasting  wholesome  product 
eminently  well  adapted  for  frying  fish  and  such  like  cooking 
operations.  In  connection  with  this  the  following  table  by 
Grimshaw  is  of  interest,  showing  the  way  in  which  a  ton  of  seeds 
is  practically  utilised  : — 

Cotton  seeds   =   2000  pounds. 

i 

About  1089  Ibs.  of  "  Meats  "       About  20  Ibs.        About  891  Ibs.  of  "Hulls" 
or  decorticated  seeds  ready  of  Lint.  ultimately  separated  into 

for  crushing 


Fibre  used  for  high  class 

papermaking. 
About  800  Ibs.  About  289  Ibs.  of  „    ,    .,         ,          ,     ,.  , 

Oilcake  used  Crude  oil.  Fu^  the  ashes  °f  ^ 

for  cattle  feeding.  After  refining  this  J™  an  excellent  fer' 

yields  tlllser' 


I 

Summer  yellow  (refined).  Foots, 

After  chilling  and  filterpressing,  &c.,       used  for  soapmaking,  &c. 
this  yields 


Winter  yellow.  Cotton  seed  stearine. 


VEGETABLE    LARD.  305 

Cotton  Seed  Stearine  (Vegetable  Margarine). — When 
cotton  seed  oil  is  chilled,  a  portion  solidifies  as  solid  glycerides ; 
when  these  are  separated  by  "  bagging  "  or  the  use  of  a  filterpress 
(p.  229),  and  subsequently  subjected  to  hydraulic  pressure,  a  com- 
pletely solid  fat  results.  The  more  solid  substances  thus  obtained 
are  largely  used  as  ingredients  in  artificial  butter ;  the  physical 
characters,  and  especially  the  melting  point,  vary  somewhat  with 
the  extent  to  which  the  expression  has  been  carried  ;  usually 
cotton  seed  stearine  is  pressed  so  as  to  melt  at  a  little  above  30°. 

Amongst  the  Hindoos  and  others  whose  religious  beliefs 
preclude  the  use  of  animal  fats  for  edible  and  cooking  purposes, 
a  large  sale  now  exists  for  purely  vegetable  fats  of  buttery  con- 
sistence (vegetable  lard) ;  the  process  of  semisolid  stearine 
extraction  from  vegetable  oils  (such  as  cotton  seed,  cokernut, 
and  many  other  native  oils)  is  consequently  somewhat  largely 
adopted  for  the  purpose  of  meeting  this  demand ;  quite 
irrespective  of  the  illegitimate  use  of  these  products  for  purely 
adulterative  purposes  in  reference  to  more  highly  priced  animal 
fats,  especially  butter  and  lard. 

Another  substance,  improperly  called  cotton  seed  stearine,  is 
obtained  by  distilling  with  superheated  steam  the  mixture  of 
organic  acids  formed  when  a  mineral  acid  is  made  to  decompose 
the  "  foots  "  obtained  during  the  process  of  refining  cotton  seed 
oil  by  alkalies  (p.  261),  and  pressing  out  the  "oleine"  from  the 
distillate  after  cooling  and  solidification.  Products  of  this  kind 
appear  to  contain  a  large  amount  of  un  saturated  solid  fatty 
acids,  possibly  isoleic  acid  (p.  29).  A.  H.  Allen  found  that  a 
"  stearine  "  of  this  kind  had  the  specific  gravity  0-868  at  99°, 
and  melted  at  40°,  whilst  the  iodine  number  was  89 '9  ;  the  theo- 
retical value  for  pure  isoleic  (oleic)  acid  being  90'1. 

Recent  Cultivation  of  Sunflower  Seeds  in  Russia. — Of 
late  years  the  oil  obtained  in  Russia  from  sunflower  seeds  has 
very  largely  displaced  the  other  cooking  and  table  oils  (chiefly 
poppy  and  hemp)  in  popular  estimation,  and  the  cultivation  of 
the  plant  has  increased  enormously;  with  due  care  in  the  drying 
and  cleaning  of  the  seeds,  the  oil  first  expressed  is  equal  to  the 
best  French  table  oils  in  colour,  flavour,  and  taste.  The  shells 
form  a  considerable  article  of  trade  for  heating  purposes,  whilst 
the  stalks,  dried  in  piles,  are  preferred  even  to  pine  wood  for 
producing  a  quick  and  hot- flame  fire ;  each  acre  yields  about 
2,000  Ibs.  of  such  firewood  and  some  1,350  Ibs.  of  oil.  The  ashes 
contain  much  potash ;  1,000  Ibs.  of  dried  stalks  yield  5  7 '2  of 
ash,  from  which  about  35  per  cent,  of  the  best  potashes  are 
obtainable.  The  oilcakes  are  looked  upon  as  the  best  in  Russia ; 
superior  to  either  hemp  or  rape  seed  cake ;  upwards  of  2,000,000 
Ibs.  are  exported  by  the  Government  of  Saratov  alone.  The 
seed  cups  are  used  as  food  for  sheep.  In  the  larger  mills  the 
process  of  extraction  is  much  the  same  as  that  used  in  England 

20 


306  OILS,    FATS,    WAXES,    ETC. 

for  linseed  and  rape  seed  (Chap.  XL),  the  shelled  seeds  being 
dusted  and  crushed  to  a  paste  in  a  steam  heated  vessel ;  the 
warm  paste  is  wrapped  in  camel's  hair  webbing,  and  pressed. 
•Out  of  104  oil  mills  in  Russia,  85  are  employed  solely  in 
obtaining  sunflower  oil,  steam  being  used  in  24,  and  manual 
labour  only  in  the  others  (Journ.  Soc.  of  Arts,  March  18,  1892). 

Manufacture  of  Lard. — The  fatty  tissues  of  the  hog  when 
properly  rendered  furnish  a  white  semisolid  grease  considerably 
softer  than  the  corresponding  fat  (tallow)  from  oxen  and  sheep, 
chiefly  differing  therefrom  in  containing  more  olein  and  less 
solid  glycerides.  In  most  of  the  larger  American  hog  slaughter- 
ing factories  the  fats  from  different  parts  of  the  body  are  kept 
separate  from  one  another,  each  being  treated  in  a  steam  render- 
ing pan  reserved  for  that  kind  only  ;  s@  that  different  grades  are 
obtained  of  considerable  constancy  of  character.  The  fat  from 
the  vicinity  of  the  kidneys,  and  the  "leaf"  fat  from  underneath 
the  skin  furnish  a  superior  and  harder  lard;  whilst  the  fats  from 
tainted  carcases  and  diseased  hogs,  being  generally  melted  down 
all  together,  produce  the  lowest  grade.  The  finest  qualities  are 
usually  put  up  in  bladders,  and  the  other  sorts  in  kegs,  whence 
the  terms  "bladder  lard"  and  "keg  lard"  are  respectively  applied. 
Bladder  lard,  when  pure,  fuses  at  42°  to  45° ;  keg  lard  at  28°  to 
38°,  according  to  its  quality  (Allen).  The  particular  texture 
exhibited  by  any  given  example  depends  largely  on  the  way  in 
which  the  cooling  and  solidification  of  the  fused  fat  was  effected, 
the  texture  being  rendered  firmer  "by  stirring  during  solidifica- 
tion, or  subsequent  chilling  in  a  refrigerating  chamber.  Some- 
times water,  salt,  and  a  variety  of  other  weigh tgiviDg  adul- 
terants (such  as  Iceland  moss  and  starch)  are  stirred  in  for  the 
purpose  of  increasing  the  solidity  of  the  mass.  Sodium  carbonate 
solution  thus  admixed  whitens  the  fat,  and  enables  it  to  hold  a 
larger  proportion  of  water.  The  chief  sophistication  of  American 
lard  consists  in  subjecting  the  pure  lard  to  pressure  so  as  to 
express  "lard  oil"  (p.  231),  and  then  working  up  the  residue 
with  cotton  seed  or  other  cheap  oil  so  as  ultimately  to  obtain  a 
mass  of  the  proper  consistency  and  texture ;  beef  suet,  mutton 
tallow,  and  other  fatty  matters  being  often  also  introduced. 
A  test  at  one  time  much  relied  on  for  the  detection  of  cotton 
seed  oil  in  such  mixtures  was  Becchi's  silver  nitrate  test 
(variously  modified  by  different  chemists*),  depending  on  the 
reduction  by  some  constituent  of  cotton  seed  oil  of  silver  from 
silver  nitrate,  with  the  formation  of  a  brown  mass  in  a  way 
not  observed  with  other  fats,  &c. ;  but  latterly  it  has  been 
found  that  by  thoroughly  refining  or  otherwise  treating  the 
cotton  seed  oil  this  constituent  is  mostly  either  removed  or 
altered,  so  that  the  presence  of  that  oil  is  no  longer  indicated 
.  with  certainty  by  silver  nitrate.  Sesame  oil,  cokernut  butter, 

*Vide  Analyst,  1887,  170 ;  1SSS,  95,  161,  et  seq. 
ti 


LARD. 


307 


and  similar  materials  are  also  used  as  admixtures,   generally 
along  with  more  or  less  harder  fat,  especially  "  beef  stearine." 

According  to  A.  H.  Allen  the  presence  of  any  considerable 
quantity  of  cotton  seed  stearine  or  coker  butter  may  be  detected 
by  the  effect  produced  on  the  relative  density,  melting  point, 
saponification  equivalent,  and  iodine  number,  as  indicated  by  the 
following  table  :— 


Lard. 

Cokernut  Butter. 

Cotton  Seed 
Stearine. 

Specific  gravity  at   '  ~»  * 
lo  *o 

•860--861 

•SG8--874 

... 

Specific  gravity  at  37°  '8    \ 
(=100°F.),t        .         .  J 

•903--907 

•910-  -916 

•911-  -912 

Melting  point, 
Saponification  equivalent, 

33°-45° 
286°-292° 

20°-28° 

209°-228° 

32° 

285°-  294° 

Iodine  number, 

59-62 

9 

The  percentage  of  water  present  is  determined  as  described  on 
p.  122;  substances  insoluble  in  ether  (starch,  limesoap,  <fec.)  as 
indicated  on  p.  123.  Mineral  nonvolatile  matters  (lime,  salt, 
alum,  <kc.)  may  be  found  by  incineration:  soluble  substances 
(salt,  alum,  &c.)  by  agitating  thoroughly  with  hot  water  and 
separating  the  aqueous  solution  for  further  examination. 

Pure  unadulterated  lard  has,  according  to  various  authorities, 
the  total  acid  number  192-197,  corresponding  with  the  saponi- 
fication equivalent  285-292,  averaging  about  289,  whence  the 
mean  equivalent  of  the  fatty  acids  is  about  277  (p.  1G5);  the 
average  value  directly  found  is  near  278.  The  iodine  number 
has  been  found  to  lie  between  50  and  64,  indicating  about  two- 
thirds  olein  and  one-third  palmitin  and  stearin  as  the  essential 
composition.  Traces  of  unsaponifiable  matters  (0*2— 0'3  percent.) 
are  also  generally  present.  When  perfectly  fresh,  lard  contains 
only  minute  quantities  of  free  fatty  acids,  less  than  1  per  cent,  j 
larger  amounts  are  usually  found  in  stale  or  partly  rancid  lard. 

When  chilled  to  0  and  pressed,  lard  furnished  a  solid  stearine 
(sometimes  known  as  solar  stearine)  and  lard  oil  (p.  231) :  the 
examination  of  the  fluid  oil  thus  obtained  is  often  better  adapted 
than  that  of  the  original  lard  for  the  purpose  of  detecting  adul- 
teration ;  thus  admixture  of  cotton  seed  oil  largely  increases  its 
iodine  number,  and  interferes  with  the  formation  of  a  solid  elaidin 
(p.  137),  and  similarly  in  other  cases.  Still  better  results  are  ob- 
tained on  separating  the  solid  and  liquid  fatty  acids  by  Muter 
and  Koningh's  process  and  examining  the  latter  apart  (Chap,  xv.) 

Artificial  Lard. — This  name  is  sometimes  applied  to  various 
mixtures  of  "  beef  stearine  "  (vide  infra)  and  cotton  seed  oil,  or 
similar  hard  fats  and  vegetable  oils,  in  such  proportions  as  to 


Water  at  15° '5  =  1. 


t  Water  also  at  37°' 8  =  1. 


308  OILS,    FATS,    WAXES,    ETC. 

give  a  product  possessing  the  consistency  of  genuine  lard. 
These  substances  are  less  frequently  sold  under  names  clearly 
indicating  their  nature  than  used  for  admixture  in  larger  or 
smaller  proportions  with  genuine  lard  for  purposes  of  sophisti- 
cation. According  to  some  writers  adulterations  of  this  kind 
are  becoming  much  less  common  than  they  were  a  few  years 
ago ;  but  it  is  doubtful  if  any  great  improvement  has  really 
taken  place  in  the  trade,  as  a  whole. 

Manufacture  of  Artificial  Butter. — Several  processes  are 
in  use  whereby  the  more  fusible  portions  of  fresh  animal  fatty 
matters  are  separated  from  the  more  solid  constituents,  so  as  to 
yield  a  mass  of  buttery  consistence  which,  when  treated  with 
annatto  or  other  harmless  vegetable  colouring  matter,  and 
churned  up  with  milk  or  otherwise  treated  so  as  to  acquire  a 
weak  buttery  flavour,  furnishes  a  cheap  palatable  foodstuff.  The 
better  kinds  of  product  thus  obtained  are  undeniably  valuable 
additions  to  the  general  food  supply ;  but  the  practice  of  mixing 
them  with  genuine  cow's  butter  and  selling  the  mixture  (or  the 
substitute  alone)  at  considerably  above  its  proper  value  under 
the  name  of  "butter,"  is  obviously  not  a  desirable  one.*  More- 
over, the  inferior  kinds  of  oleomargarine  are  not  invariably  of 
harmless  character,  as  the  earlier  forms  of  tapeworm  (cysticerci) 
and  other  entozoa  are  sometimes  present. 

The  earliest  processes  are  said  to  date  commercially  from  the 
Franco-German  war,  when  the  scarcity  of  butter  in  Paris  during 
the  siege  led  to  the  utilisation  of  various  other  forms  of  fat  (more 
especially  that  of  horses)  and  their  treatment  so  as  to  obtain  a 
softer  and  more  palatable  substance.  The  original  Mege  Mouries 
process  consists  in  treating  chopped-up  adipose  tissue  with  a 
weak  alkaline  solution  (potassium  carbonate)  and  minced  sheep's 
or  hog's  stomach  at  about  45°  C.,  when  partial  digestion  of  the 
albuminous  fatty  envelopes  and  cellular  tissue  is  brought  about 
so  that  the  fat  separates,  being  "rendered"  completely  at  the 
comparatively  low  temperature  used.  On  cooling  and  standing 
the  solid  glycerides  more  or  less  completely  separate  in  a  crystalline 
form,  so  that  by  applying  pressure  in  cloths  in  an  ordinary 
hydraulic  press  (p.  231)  the  still  liquid  portion  is  squeezed  out, 
whilst  a  tolerably  hard  mixture  of  glycerides  is  left,  valuable  for 
candlemaking.  Instead  of  alkaline  potash  solution  dilute  hydro- 
chloric acid  is  preferred  by  some,  more  especially  with  an  addition 
of  calcium  phosphate,  so  as  to  form  phosphoric  acid  or  an  acid 
phosphate  of  calcium  :  the  digestive  action  is  thus  promoted  and 
hastened. 

Much  of  the   "bosch,"  "Dutch    butter,"  "butterine,"  "mar- 
garine,"! and  "oleomargarine"  of  the  present  day  is  prepared 

*  In  certain  of  the  United  States  the  Legislature  requires  that  oleomar- 
garine must  be  coloured  pink  in  order  to  prevent  its  being  sold  as  butter, 
f  The    term  "margarine"  is  an  unfortunate  survival  of  a  misnomer 


ARTIFICIAL    BUTTER.  309 

by  processes  analogous  to  that  of  Mege  Mouries,  excepting  that 
the  digestive  operation  is  omitted.  The  sorted  adipose  tissue 
(carefully  handpicked,  and  sometimes  washed  to  separate  traces 
of  blood  and  suchlike  animal  matters,  and  then  finely  minced)  is 
subjected  to  gentle  heat ;  in  some  cases  alone,  so  that  the  more 
fusible  constituents  liquate  away  from  the  rest,  the  mass  being 
supported  in  trays  on  sloping  racks  in  a  room  kept  at  a  temper- 
ature not  much  exceeding  50°  C. ;  in  other  cases  in  tubs  in  contact 
with  water  at  about  45°— 48°,  when  the  more  fluid  matters  gradu- 
ally float  up  and  are  withdrawn  from  time  to  time.  Beef  suet 
is  the  preferable  material,  but  sheep's  fat  is  also  employed ;  much 
of  the  margarine  made  in  America  is  derived  from  hog's  fat, 
being  in  fact  a  variety  of  lard  from  which  much  of  the  solid 
matter  has  been  removed.  The  partially  exhausted  tissues  left 
are  rendered  in  the  usual  way  (p.  245),  either  alone  or  mixed 
with  other  fatty  matters,  so  as  to  produce  a  superior  quality  of 
tallow  :  the  oleaginous  fluid  matters  that  result  from  the  first 
processes  are  cooled  and  kept  at  about  25°  for  some  time  to  allow 
the  solid  glycerides  to  crystallise,  and  the  mass  is  then  pressed. 
The  solid  pressed  residue  is  generally  known  as  "  beef  stearine," 
and  is  largely  used  in  the  manufacture  of  factitious  lard  by 
incorporation  with  cotton  seed  or  other  fluid  vegetable  oil  so 
as  to  form  a  mass  of  the  required  physical  consistency. 

The  resulting  expressed  oil  acquires  a  buttery  consistence  at 
the  ordinary  temperature,  but  is  usually  somewhat  softer  than 
cow's  butter ;  by  thoroughly  churning  it  up  with  fresh  (or,  as 
preferred  by  some,  sour)  milk,  and  a  little  minced  cow's  udder, 
it  acquires  a  slightly  firmer  consistence  and  a  buttery  flavour. 
If  the  temperature  during  pressing  has  been  too  high,  or  if  the 
solid  glycerides  have  not  sufficiently  thoroughly  separated  whilst 
standing,  the  expressed  substance  may  be  too  solid,  in  which 
case  it  is  admixed  with  fluid  vegetable  oil  (cotton  seed,  arachis, 
sesame,  tire.)  The  temperature  at  which  the  churning  is  effected 

applied  to  certain  fat  constituents  in  earlier  days  before  the  chemistry  of 
these  substances  was  well  elucidated.  By  saponifying  tallow,  lard,  and 
other  animal  fats,  and  separating  the  fatty  acids  thence  ultimately  obtained 
as  far  as  practicable,  various  substances"  were  got  of  somewhat  different 
characters  in  different  cases,  but  mostly  consisting  of  a  liquid  fatty  acid 
(oleic  acid) ;  a  solid  constituent  melting  at  about  75°,  known  originally  as 
maryarous  acid  (Chevreul),  subsequently  as  stearic  acid;  and  another  solid 
product  termed  maryaric  acid,  crystallising  in  pearly  scales  (whence  the 
name,  from  /mupyapov,  or  ^npyupiT^  —  pearl),  and  melting  at  a  lower 
temperature,  near  60°.  This  last  was  long  regarded  as  a  single  substance 
indicated  by  the  formula  C^H^C^;  the  glyceride  containing  it  in  the 
original  fat  was  accordingly  known  as  margarine.  Subsequently,  how- 
ever, it  was  shown  by  Heintz  that  this  pearly-scale  crystalline  substance 
was  a  mixture  of  homologous  substances,  consisting  chiefly  of  stearic  and 
palmitic  acids;  and  that  whilst  true  margaric  acid,  C]7Hg402,  could  be 
produced  artificially  (p.  21),  it  was  not  a  product  of  the  saponification  of 
natural  fats,  and  its  supposed  glyceride,  margarine,  was  not  contained 
therein. 


310  OILS,    FATS,    WAXES,    ETC. 

has  a  good  deal  of  influence  on  the  physical  character  of  the 
product;  preferably  the  factitious  "butter"  is  withdrawn  and 
quickly  chilled,  either  by  running  into  ice  cold  water  or  on  to 
slabs  of  solid  ice,  and  then  made  up  into  "  pats  "  for  the  market. 
Annatto,  turmeric,  saffron,  and  various  other  colouring  matters 
(preferably  vegetable,  but  sometimes  of  coaltar  origin)  are  used 
to  communicate  a  yellow  tint ;  sometimes  a  minute  quantity  of 
butyric  ether  or  other  special  flavouring  and  odour-giving  sub- 
stance is  added.  Inferior  kinds  of  socalled  margarine  are  some- 
times made  by  the  simple  process  of  working  up  comparatively 
hard  fats  (such  as  moderately  scentless  tallow)  with  fluid  vegetable 
oils,  coker  butter,  lard  oil,  and  similar  softer  materials ;  when  such 
mixtures  are  further  incorporated  with  more  or  less  stale  genuine 
butter  and  churned  up  with  milk,  &c.,  products  are  obtained  very 
closely  simulating  genuine  butter  of  second  or  third  rate  quality  ; 
they  may  be  made  to  correspond  with  actual  butter  so  closely  as 
to  pass  most  of  the  tests  applicable  thereto,  excepting  that  a  more 
or  less  marked  increment  is  observable  in  the  "  Hehner  number ;5 
(p.  166),  and  a  decrement  in  the  Reichert  number  (p.  173) ;  with 
in  many  cases  a  slight  depreciation  of  the  specific  gravity. 

Margarine  and  oleomargarine  prepared  from  solid  animal  fats, 
without  admixture  with  cokernut  oil,  possess  a  higher  total  acid 
number  than  genuine  butter — viz.,  192  to  199 — corresponding 
with  the  saporiification  equivalent  282  to  293  (tripalmitin 
=  268-7,  trioleine  =  294-7,  tristearin  -  296-7) ;  the  iodine 
number  is  also  higher,  being  usually  between  45  and  55;  but  since 
methods  have  been  discovered  *  for  removing  the  characteristic 
odour  of  cokernut  oil,  the  deodorised  substance  can  be  admixed 
with  animal  margarine  in  such  fashion  as  to  bring  down  both  the 
saponification  equivalent  and  iodine  number  to  close  to  the 
figures  observed  with  genuine  butter.  Moreover,  since  cokernut 
and  palmnut  oils  furnish  much  smaller  percentages  of  insoluble 
fatty  acids,  and  larger  ones  of  volatile  acids  than  ordinary  soft 
animal  fats,  their  admixture  in  the  mass  tends  to  lower  the 
Hehner  number,  and  raise  the  Eeichert  number,  thus  rendering 
detection  by  these  tests  more  difficult. 

The  following  table,  based  on  one  given  by  Schadler,f  repre- 
sents the  wray  in  which  the  fatty  matter  from  an  ox  is  utilised : — 

*  Schlink's  method  for  removing  the  volatile  and  odorous  fatty  acids,  &c. , 
from  cokernut  oil,  consists  in  treatment  with  alcohol  and  animal  charcoal, 
whereby  a  perfectly  white  mass  is  obtained,  of  the  consistency  of  butter, 
and  of  sweet  neutral  agreeable  flavour.  A  very  considerable  sale  for  the 
product  exists,  nominally  as  a  "  vegetable  lard "  for  cooking  purposes 
(supra)  ;  practically,  however,  the  material  is  largely  if  not  mainly  em- 
ployed in  sophisticating  cow's  butter.  For  a  description  of  tests  emploj^ed 
in  the  examination  of  butter  supposed  to  be  thus  adulterated,  vide  F.  Jean, 
Moniteur  Stientifique,  1890,  36,  p.  1116;  in  abstract,  Journ.  Soc.  Chem.  Ind., 
1891,  p.  275. 

t  From  results  obtained  in  Sarg's  factory,  Vienna. 


UTILISATION   OF    OX   FAT. 


311 


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312  OILS,    FATS,    WAXES,    ETC. 

FINAL  PRODUCTS. 

"  Artificial  butter,"  about  18  kilos,  representing  of 

oleomargarine,     ....  about  16'5  kilos. 


Pure  commercial  "  glycerine," 

"  Stearine  "  (stearic  and  palmitic  acids), 

"  Oleine  "  (impure  oleic  acid), 

"  Scraps  "  used  for  manure, 


2-5 
24-0 
23-5 
16-5 


83-0 


It  would  hence  seem  that  a  very  considerable  loss  of  glycerol 
accompanies  the  various  processes  gone  through  in  the  course  of 
the  isolation  of  the  pure  redistilled  commercial  article;  for 
24  kilos,  of  stearic  acid,  together  with  23-5  of  oleic  acid,  theo- 
retically correspond  with  about  5 -3  kilos,  of  glycerol  instead  of 
2-5,  indicating  a  total  loss  of  more  than  50  per  cent,  of  the 
glycerol  formed  during  saponification. 


LAMP  OILS. 

From  the  earliest  ages  the  use  of  lamps  has  been  general, 
essentially  consisting  of  a  vessel  for  holding  the  oily  matter, 
provided  with  some  kind  of  porous  wick  up  which  the  oil  rises, 
by  capillary  action,  to  supply  the  place  of  that  burnt  in  the 
flame.  Probably  this  arrangement  was  actually  a  development 
of  the  still  earlier  torch  or  flambeau,  consisting  in  its  simplest 
form  of  a  splinter  of  pine  containing  natural  resin,  and  in  a  more 
elaborate  shape  of  strands  of  vegetable  fibre  dipped  in  resin, 
asphalt,  and  similar  materials  (obviously  the  prototype  of  the 
more  modern  wicked  candle).  The  wicks  used  in  some  of  the 
early  forms  of  lamp  appear  to  have  been  of  rush-pith,  apparently 
closely  akin  to  the  rush-candle  or  rush-light ;  saving  that  in  the 
latter  the  vegetable  wick  was  dipped  in  a  comparatively  solid 
fat  melted  by  heat,  and  then  taken  out  and  allowed  to 
harden,  whilst  in  the  former  the  wick  was  held  in  position  by 
some  simple  device,  and  a  thinner  fat  or  oil  used,  fluid  enough 
to  moisten  the  wick  without  extraneous  heat.  In  the  modern 
"  nightlight  "  both  forms  are  substantially  combined,  the  arrange- 
ment being  virtually  a  candle  on  first  lighting,  and  practically  an 
oil  lamp  after  burning  sufficiently  long  to  melt  the  remainder  of 
the  fatty  matter  by  the  heat  developed. 

Amongst  the  Eastern  nations,  crude  natural  naphtha  or 
petroleum  has  been  largely  used  as  a  burning  oil  from  time 
immemorial ;  but  the  methods  now  in  use  for  purifying  it  and 
separating  it  into  different  fractions  (some  of  which  are  far  better 
adapted  for  burning  in  lamps  than  the  raw  material,  whilst  others 
are  quite  unfit  for  that  purpose)  are  of  quite  modern  origin. 
Amongst  the  Greeks  and  Romans,  olive  oil  appears  to  have  been 


LAMP    OILS.  313 

largely  used  for  the  purpose  ;  whilst  rough  candles  of  tallow, 
and  superior  ones  of  wax,  were  also  in  use.  In  all  the  early 
forms  of  household  lamp  no  chimney  was  employed,  so  that  the 
flame  was  invariably  more  or  less  smoky,  a  circumstance  which 
considerably  limited  the  number  of  vegetable  oils  available ;  in 
1784,  Argand  introduced  the  form  of  lamp  still  bearing  his  name 
(although  greatly  altered  and  improved  by  subsequent  inventors), 
essentially  consisting  of  a  circular  wick  with  an  air  supply  in  the 
centre,  a  chimney  of  iron  (later  of  glass)  being  also  applied,  so  as  to 
increase  the  draught  and  so  facilitate  combustion,  thus  diminish- 
ing smoke  and  increasing  the  light  emitted.*  This  invention 
greatly  stimulated  the  use  of  oil  lamps,  and  colza  oil  and  sperm 
oil  soon  became  extensively  used  for  consumption  therein,  together 
with  many  other  varieties,  notably  the  oils  from  rape  seed,  ground 
nuts,  and  cotton  seed.  At  the  present  day,  however,  the  use  of 
these  oils  in  this  way,  though  by  no  means  inconsiderable,  is 
small  as  compared  with  that  of  the  hydrocarbon  oils  from 
petroleum  and  paraffin  shale,  &c.  (at  any  rate  in  those  countries 
where  the  latter  are  readily  obtainable),  on  account  of  the  greater 
cost ;  but  in  many  semicivilised  lands  the  cost  of  vegetable  oils 
indigenous  to  the  district  is  often  below  that  of  imported 
petroleum  burning  oils,  so  that  the  mineral  oils  have  in  such 
cases  not  yet  largely  supplanted  the  vegetable  ones. 

When  rape  (colza)  oil  is  burnt,  a  tendency  to  charring  of  the 
wick  appears  to  exist  if  the  oil  contain  much  free  fatty  acids 
(formed  by  decomposition  of  the  original  glycerides  during  ex- 
traction and  refining,  <fcc.)  ;  this  is  also  marked  in  the  case  of 
olive  oil.  According  to  Arch  butt,  5  per  cent,  of  free  fatty  acids 
is  the  maximum  permissible,  otherwise  a  defective  light  results, 
arid  the  wick  soon  chars. 


DRYING    OILS    USED   FOR    PAINT   MANUFACTURE 

AND   IN   THE  PREPARATION   OF  VARNISHES, 

LINOLEUM,  AND  SUCH  LIKE  PRODUCTS. 

Drying  oils,  such  as  linseed  oil,  in  their  natural  state  as 
obtained  by  expression  and  refining  (raw  oils),  absorb  oxygen 
from  the  air  and  inspissate  at  much  lower  rates  than  are  observed 
after  subjecting  them  to  a  form  of  treatment  usually  spoken  of  as 
"  boiling/'  although  the  term  is  not  strictly  correct,  inasmuch  as 
the  oils  do  not  become  converted  into  vapour  capable  of  recon- 

*  Flues  or  chimneys  applied  to  lamps  were  not  wholly  unknown  to  the 
ancients  ;  thus  the  lamp  (of  pure  gold),  designed  by  Callimachus  about 
400  B.C.  for  the  Erechtheum  of  the  Athens  Acropolis,  was  provided  with  a 
chimney  in  the  form  of  an  inverted  palm  tree  of  bronze.  Argand's  use  of  a 
chimney  was  also  previously  suggested  by  Quinquet  (Leopold  Field,  Cantor 
Lectures,  Soc.  of  Arts  Journ.,  1883,  pp.  826  and  848). 


314  OILS,    FATS,    WAXES,    ETC. 

densation  to  the  original  substance  as  water  or  alcohol  does  when 
boiled,  but  only  become  partially  decomposed  so  as  to  evolve 
vapours  in  consequence  of  incipient  destructive  distillation 
(p.  125)  or  other  decomposition,  more  especially  of  the  glyceridic 
portion  of  the  molecule,  whereby  acrolein  is  formed. 

In  the  older  processes  for  preparing  "boiled"  oils,  this  effect 
was  brought  about  by  heat  alone ;  subsequently  various  sub- 
stances known  as  "driers"  were  added  to  the  oil  in  small 
quantity  for  the  purpose  of  promoting  the  particular  changes  in 
view.  In  the  more  modern  methods  somewhat  lower  tempera- 
tures are  mostly  employed,  whilst  the  action  is  accelerated  by 
injecting  air  into  the  hot  mass,  whereby  a  greater  degree  of 
incipient  oxidation  is  effected,  the  result  of  which  is  to  render 
the  oil  much  more  prone  to  oxidise  spontaneously  by  subsequent 
exposure  to  air,  and  hence  to  "  dry  "  more  rapidly. 

The  nature  of  the  driers  used,  and  the  exact  methods  of  mani- 
pulation are  often  supposed  to  be  valuable  trade  secrets ;  but  the 
practical  result  of  working  secret  "  rule  of  thumb  "  methods  of 
the  kind  has  not  always  proved  commercially  successful.  Some 
of  the  substances  used  under  the  name  of  "  driers  "  (e.g.,  dried 
alum,  and  zinc  sulphate)  contribute  but  little,  if  anything  at  all, 
to  the  drying  effect,  their  action  being  simply  to  coagulate  re- 
maining mucilage,  and  aid  its  subsequent  removal  by  subsidence. 
Numerous  metallic  salts  and  oxides,  <kc.,  are,  or  have  been, 
employed  for  the  purpose ;  according  to  the  experiments  of 
Livache,  the  most  marked  effect  in  the  way  of  increasing  the 
rate  of  drying  is  produced  by  manganese  and  lead  salts,  copper, 
cobalt,  and  zinc  compounds  being  much  less  active,  and  salts  of 
iron,  chromium,  and  nickel  still  less  so.  In  actual  practice,  com- 
pounds of  lead  are  those  most  frequently  used,  especially  litharge, 
red  lead,  and  lead  acetate ;  the  result  of  which  is  that  the  boiled 
oil  finally  obtained  contains  lead  in  solution  as  some  kind  of  lead 
soap  (to  the  formation  of  which,  in  the  first  instance,  the  action 
of  improving  drying  qualities  is  probably  due,  the  lead  soap  acting 
as  carrier  of  oxygen) ;  hence,  more  or  less  discoloration  of  paint 
made  with  such  oil  is  apt  to  occur,  especially  in  towns,  inde- 
pendently of  that  brought  about  by  the  white  lead  added  to  most 
kinds  of  paint.  This  result  is  avoided  by  substituting  manganese 
salts,  &c.,  for  lead  compounds  ;  accordingly,  manganese  hydroxide, 
dioxide,  borate,  oleate,  oxalate,  and  other  organic  salts  are  now 
.somewhat  largely  employed.* 

When  the  drier  is  added  in  fine  powder,  a  considerable  fraction 
of  it  can  be  recovered,  as  it  settles  to  the  bottom  when  the  oil  is 
allowed  to  cool  and  stand ;  but  a  portion  is  taken  into  solution 
as  metallic  soap  and  permanently  retained  in  the  oil.  Apparently 

*  According  to  K  Clarke  (Journ.  Soc.  Art*,  Feb.  10,  1893,  p.  289),  boiled 
oil  prepared  with  manganese  is  unsuitable  for  varnish  making,  as  it  produces 
a  bloom  on  any  varnish  made  with  it. 


DRYING    OILS.  315 

this  soap  absorbs  oxygen  from  the  air,  and  then  in  some  way 
parts  with  it  again  to  the  glycerides  present ;  but  the  precise  way 
in  which  the  carrying  action  is  effected  is  not  thoroughly  under- 
stood. In  some  cases,  if  too  large  a  proportion  of  metallic  soap 
is  formed,  the  boiled  oil  produced  is  deteriorated,  probably  because 
the  oxidising  action  then  gets  carried  too  far.  By  the  use  of  the 
drier  in  the  form  of  a  solution  of  known  strength,  any  required 
proportion  can  be  readily  introduced;  manganese  oleate  or 
linolate,  or  other  fatty  acid  manganese  soap,  dissolved  in  oil  of 
turpentine  or  similar  solvent,  is  accordingly  coming  into  use  for 
the  purpose,*  more  especially  for  oils  intended  to  mix  with  zinc 
white  or  other  pigments  of  light  tint  where  darkening  is  desired 
to  be  avoided,  such  as  is  liable  to  be  produced  in  lead-containing 
oil  by  the  action  of  sulphur  compounds  in  the  air.  Moreover, 
oils  "  boiled "  with  manganese  driers  are  generally  of  a  lighter 
colour  than  when  lead  is  used.  Occasionally,  to  meet  trade  pre- 
judices as  regards  colour,  a  mixture  of  lead  and  manganese  com- 
pounds is  used,  so  that  the  darker  red  tint  produced  by  the  lead 
may  be  developed  to  an  extent  proportionate  to  the  quantity  of 
lead  employed. 

The  proportion  of  driers  employed  is  usually  but  small,  not 
exceeding  0-25  to  O75  per  cent,  of  the  weight  of  the  oil  (a  few 
Ibs.  per  ton) ;  when  used  in  the  solid  form  it  is  important  that 
they  should  be  in  the  finest  possible  state  of  division,  for  which 
purpose  they  are  usually  subjected  to  a  process  of  levigation  after 
continued  grinding ;  finally,  they  are  ground  with  oil,  much 
as  paint  is  ground,  so  as  to  form  a  mixture  that  can  be  readily 
disseminated  through  the  mass  of  oil  treated  by  means  of 
agitators. 

In  the  older  method  of  "  boiling,"  the  oil  is  simply  heated 
along  with  the  driers  for  some  hours  to  a  temperature  varying 
from  200°  to  250°  C.,  free  fire  being,  used  as  the  heating  agent. 
Fig.  76  represents  the  kind  of  arrangement  employed ;  a  lid,  e, 
is  arranged,  capable  of  being  lowered  on  to  the  pan,  a,  and 
closing  it  up  airtight  by  means  of  the  flanged  rim,  b  b,  so  that  in 
the  event  of  the  evolved  vapours  taking  fire  they  can  be  almost 
instantaneously  extinguished.  To  avoid  frothing  over,  the  part 
is  originally  filled  not  more  than  half  full  with  oil. 

Fig.  77  represents  a  pair  of  steam  heated  kettles,  the  jackets 
being  strong  enough  to  resist  several  atmospheres  pressure  : 
usually  4  to  5  atmospheres  are  employed,  the  oil  being  heated  to 
1 30°  0.  or  a  little  upwards.  When  air  is  blown  through  the  hot 

*  Hartley  &  Blenkinsop's  process  (Patent  No.  11,629,  1890)  combines  the 
drying  action  of  manganese  soap  added  in  this  form  with  the  bleaching 
action  produced  by  blowing  a  current  of  air  through  the  mass  at  a  tempera- 
ture a  little  short  of  100°  C. ;  by  using  only  a  small  proportion  of  manganese 
linolate  solution,  the  oxidising  action  can  be  almost  wholly  confined  to  the 
colouring  matter,  so  as  to  bleach  the  oil  without  producing  any  notable 
degree  of  other  oxidation  (Journ.  Soc.  Arts,  loc.  ctt.  supra). 


316 


OILS,    FATS,    WAXES,    ETC. 


oil  a  dome-shaped  cover  is  fitted  on  to  keep  in  splashes,  provided 
with  an  exit  pipe  for  the  vapours  evolved. 

An  improved  vessel  for  boiling  oil  and  suitable  for  many  other 
kindred  purposes  has  been  recently  described  by  T.  Frederking.* 


Fig.  76. 

A  coil  of  stout  piping  is  arranged  in  a  casting  mould  so  that  the 
molten  metal  forming  the  pan  is  cast  round  the  coil ;  much  as  is 
done  in  the  case  of  the  water-tuyeres  of  a  blast  furnace.  Steam 
at  any  required  pressure  being  passed  through  the  coil,  the  pan 

*  Chemical  News,  Jan.  27,  1893  :  German  Patent  No.  63,315. 


BOILED    OILS.  317 

is  heated  up  proportionately  without  any  danger,  the  pressure 
bearing  solely  on  the  piping  and  not  on  the  metal  pan  itself, 
whilst  the  well-conducting  metal  walls  allow  the  heat  to  pass 
readily.  Temperatures  up  to  350°  and  400°  C.  can  be  thus 
obtained. 

According  to  C.  W.  Vincent  *  the  use  of  air  alone  without 
driers  does  nothing  towards  making  oil  "  drying."  Linseed  oil 
heated  for  three  days  consecutively  at  a  high  temperature  in 
presence  of  the  air  but  without  driers  required  the  same  time  to 
dry  as  the  raw  oil  from  which  it  was  prepared,  but  the  "  body  " 
was  much  increased.  Heating  alone  for  the  same  time  with  only 
surface  exposure  to  air  produced  no  such  increase  of  body ;  the  oil 
became  more  greasy,  less  penetrative,  and  less  drying. 

The  exact  nature  of  the  changes  taking  place  during  the  boiling 
of  drying  oils  is  not  clearly  understood  ;  beyond  the  fact  than  an 
incipient  alteration  is  produced  (either  by  decomposition  by 


Fig.  77. 

heat,  or  by  oxidation,  or  both  together,  largely  assisted  by  the 
carrier  action  of  the  driers),  which  tends  in  the  direction  of  the 
further  changes  effected  by  the  absorption  of  oxygen  whilst 
drying,  little  is  known  with  certainty.  No  considerable  destruc- 
tion of  glycerides  appears  to  occur  until  the  action  is  pushed 
very  far,  ordinary  "boiled"  linseed  oil  furnishing  nearly  the 
same  amount  of  glycerol  on  saponification  as  raw  unboiled  oil ;  on 
the  other  hand,  a  more  or  less  distinguishable  small  diminution 
in  iodine  absorbing  power  is  generally  brought  about  indicating 
oxidation.  For  the  further  changes  effected  during  actual 
"drying,"  see  pp.  129,  134. 

In  the  manufacture  of  printing  ink,  the  action  is  pushed 
considerably  further.  In  the  older  direct-firing  process  (still 
preferred  by  many)  the  oil  is  heated  until  the  escaping  vapours 

*  Muspratt's  Dictionary  of  Chemistry,  edited  by  C.  W.  Vincent,  p.  475, 
vol.  ii. 


318  OILS,    FATS,    WAXES,    ETC. 

will  fire  freely;  the  mass  thickens  considerably  as  the  action 
progresses ;  when  a  sample  taken  out  and  dropped  on  a  cold 
porcelain  surface  can  be  drawn  into  strings  half  an  inch  long, 
a  cover  is  put  on  to  extinguish  the  flame ;  amber  or  rosin  is 
then  dissolved  in  the  hot  oil,  and  slices  of  soap  (essential  in 
order  to  enable  the  ink  to  adhere  to  damp  paper) ;  and  finally 
the  pigment  (lamp  black,  ivory  black,  <fcc.,  mixed  with  prussian 
blue  or  other  coloured  pigments  to  tone  the  black  as  required). 
Obviously  in  this  case  the  heat  causes  a  partial  decomposition  of 
the  oil,  and  the  thickening  is  probably  due  largely  to  an  action 
of  polymerisation  taking  place  in  the  nascent  acids  or  anhydrides, 
thus  formed,  somewhat  analogous  to  that  which  occurs  during 
the  "vulcanising"  of  oils  by  the  action  of  sulphur  chloride,  &c. 
(p.  154). 

The  varnishlike  film  of  oxidised  oil  produced  when  boiled 
linseed  oil  is  made  to  form  a  thin  coating  on  a  suitable  large 
surface  'freely  exposed  to  the  air  can  be  increased  to  an  almost 
indefinite  extent  by  painting  a  second  film  over  the  first  when 
approaching  dryness,  and  so  on  in  succession.  The  product  thus 
formed  is  largely  employed  in  the  manufacture  of  linoleum  and 
floorcloth,  thin  sheets  of  canvas  or  cotton  scrim  being  suspended 
vertically  in  a  room  freely  supplied  with  air,  and  "  flooded  "  with 
oil  from  an  overhead  reservoir  or  tank  running  on  wheels  like  a 
travelling  crane ;  the  sheets  thus  moistened  with  a  film  of  oil 
are  kept  suspended  with  free  access  of  air,  and  when  the  coating 
is  nearly  dry,  alternate  floodings  and  exposure  to  air  are 
repeated  for  some  weeks  until  the  "skin"  formed  is  sufficiently 
thick,  the  chamber  being  supplied  with  warmed  air  if  necessary, 
so  as  to  keep  its  temperature  up  to  at  least  70°  F.  =  21°  C.,  and 
freely  ventilated,  much  acrid  vapour  (acrolein,  £c.)  being  evolved 
during  the  oxidation  by  the  destruction  of  the  glyceridic  portion 
of  the  oil.  The  oxidised  oil  thus  formed  is  heavier  than  water 
(raw  linseed  oil  has  the  specific  gravity  -935  or  thereabouts),  and 
forms  a  yellow  translucent  mass,  insoluble  in  alcohol,  ether, 
chloroform,  and  carbon  disulphide  ;  boiling  naphtha  (under 
pressure)  softens  it  so  that  it  can  be  worked  into  a  paste.  For 
the  manufacture  of  linoleum  the  skins  are  ground  between  rollers, 
and  heated  with  rosin  and  kaurie  gum  in  a  mixing  pan,  and  the 
resulting  paste  or  "cement"  then  intermixed  with  rasped  cork 
and  ultimately  spread  upon  a  canvas  backing. 

Notwithstanding  the  loss  of  weight  due  to  the  evolution  of 
acrolein  and  other  volatile  products  during  this  process,  a  gain 
in  weight  averaging  about  11  per  cent,  is  experienced,  so  that 
the  fixation  of  oxygen  is  considerable.  In  order  to  shorten 
the  time  requisite  for  the  oxidation  of  drying  oils  for  linoleum 
manufacture,  F.  Walton*  forces  air  at  a  pressure  of  5  to  10 
atmospheres  through  the  oil  warmed  to  about  100°  F.  =  37°  C., 
*  Patent  Specification  No.  12,000,  July  31,  1890. 


BLOWN    OILS.  319 

the  air  current  being  divided  by  means  of  perforated  plates ; 
an  agitator  is  provided,  by  means  of  which  the  product  when 
approaching  solidification  is  more  or  less  granulated,  whilst  fused 
gums,  &c.,  can  be  incorporated. 

Blown  Oils. — Of  late  years  the  manufacture  of  oils  oxidised 
by  the  direct  action  of  air  upon  them,  has  acquired  a  considerable 
magnitude,  the  effect  produced  usually  being  a  considerable 
increment  in  density  and  viscosity,  rendering  nondrying  or 
semidrying  oils  (rape,  cotton  seed,  fish  oils,  &c.)  more  suitable 
for  use  as  lubricants,  either  directly  or  as  ingredients  in  lubri- 
cating mixtures  :  and  in  the  case  of  drying  oils  (more  especially 
linseed  oil),  bringing  about  more  rapidly  and  certainly  those 
incipient  oxidation  changes  requisite  to  produce  more  rapid 
spontaneous  absorption  of  oxygen  from  the  air  by  the  oil,  when 
spread  out  in  thin  layers — i.e.,  the  changes  effected  in  socalled 
"  boiled  "  oil,  rendering  it  better  applicable  for  the  production  of 
paint  and  varnish,  <fcc.,  owing  to  its  more  rapidly  "drying"  up 
to  a  comparatively  hard  varnish-like  coating  when  thus  applied. 

The  plant  employed  for  the  process  is  of  simple  construction, 
consisting  of  a  pan  or  tank  fitted  with  a  steam  jacket  (or  an 
internal  dry  steam  coil)  for  heating  up  the  oil,  and  with  a  false 
bottom  perforated  with  numerous  small  holes,  cullender-fashion ; 
air  being  pumped  in  under  the  false  bottom  rises  up  through  the 
hot  oil  in  numerous  minute  streams  of  bubbles.  Instead  of  a 
false  bottom,  a  horizontal  serpentine  with  numerous  pin  holes  is 
sometimes  employed.  When  the  action  is  intended  to  be  carried 
to  the  limit,  as  in  oxidising  drying  oils  for  linoleum  making,  an 
agitating  arrangement  is  also  added  for  the  purpose  of  breaking 
up  clots,  and  keeping  the  mass  well  stirred  up  (supra). 

The  nature  of  the  chemical  changes  taking  place  during  the 
action  of  air  on  hot  lard  oil,  cotton  seed  oil,  rape  oil,  &c.,  has 
not  been  thoroughly  elucidated  ;  a  considerable  amount  of  heat 
is  developed  during  the  process,  so  that,  when  once  started,  no 
further  extraneous  heating  is  requisite,  but  in  some  cases  rather 
the  converse,  otherwise  the  temperature  may  rise  so  high  as  to- 
injure  the  product  by  incipient  decomposition.  In  all  probability 
the  olein  present  (or  other  homologous  glyceride)  becomes  largely 
converted  into  the  glyceride  of  an  oxyoleic  or  oxystearic  acid, 
either  analogous  to  the  ricinoleic  acid  of  castor  oil  (i.e.,  an 
unsaturated  hydroxylated  acid),  or  more*  probably  constituted 
like  anhydrodioxystearic  acid  (pp.  42,  46),  where  the  oxygen  is 
directly  added  on  in  the  same  way  that  iodine  or  bromine  is 
added,  so  as  to  convert  an  unsaturated  acid  into  a  saturated 
derivative ;  for  in  proportion  as  the  oxidation  proceeds,  the 
iodine  absorption  lessens.  Other  subsidiary  actions,  however, 
also  take  place ;  thus,  the  proportion  of  insoluble  acids  (Hehner 
number)  lessens  as  the  oxidation  goes  on,  whilst  increasing 
amounts  of  soluble  acids  are  formed;  the  mean  saponification 


320 


OILS,    FATS,    WAXES,    ETC. 


equivalent  of  the  blown  oil  is  usually  less  than  that  of  the 
original  oil  (i.e.,  the  "total  acid  number"  increases),  although 
but  little  increment  is  brought  about  in  the  "free  acid  number." 
Blown  oils  develop  much  more  heat  on  mixing  with  sulphuric 
acid  than  the  original  untreated  oils. 

The  following  figures  were  obtained  by  Thomson  and  Bal- 
lantyne*  in  the  course  of  a  series  of  experiments  on  the  oxidation 
of  rape  and  sperm  oils  by  blowing  hot  air  through  them  : — 

RAPE  OIL. 


Original 

Partly 
blown  after 
5  hours. 

More  fully 
blown  after 
20  hours. 

Commercial 
Blown  Rape 
Oil. 

Specific  gravity  at  15°  "5, 

0-9141 

0-9275 

0-9615 

0-9672 

Percentage  of  free  acid  (calcu-  | 
lated  as  oleic  acid),    .         .  \ 

5-10 

5-01 

7-09 

4-93 

Percentage  of  unsaponifiable  ^        rt.Rri 

0'76 

2-80 

matter,       .         .         .         .  / 

Total  acid  number, 

173-9 

183-0 

194-9 

197-7 

Iodine  number, 

100-5 

88-4 

63-2 

63-6 

Specific  temperature  reaction  ) 

135° 

253° 

(p.  149),     .         .         •     .   •  ! 

Percentage  of  insoluble  acids  )      04.  "(j 
(Hehner  number),       .         .  ^ 

... 

85-94 

82-40 

Molecular  weight  of  insoluble  ) 
acids,          .         .         .         .  (  j 

... 

327 

317 

Percentage    of    soluble   non-  \                  , 
volatile  acids,     .         .         .  f        Q'r2   < 

... 

9-20 

11-16 

Percentage  of  soluble  volatile  (                 ) 
acids,          .         .         .         .  ) 

0-82 

1-90 

Iodine    number    of    soluble  \ 

66-5             70-2 

acids,          .         .         .         .  \  ; 

I 

1 

SPERM  OIL. 


Before  blowing. 

After  blowing  for 
25  hours. 

Specific  gravity  at  15°  '5, 
Free  acid  (calculated  as  oleic) 

0-8799 
1-97 

0-8989 
3-27 

Unsaponifiable  matter,    . 
Total  acid  number, 

36-32 
130-4 

34-65 
142-3 

Iodine  number, 

82-1 

67-1 

Commercial  blown  oils  usually  present  nearly  the  same  density 
and  viscosity  as  castor  oil,  but  differ  therefrom  in  not  dissolving 
freely  in  alcohol,  whilst  they  are  readily  soluble  in  petroleum 
spirit,  and  mix  readily  with  the  heavier  petroleum  hydrocarbons, 
thus  enabling  homogeneous  .lubricating  mixtures  to  be  produced. 

*  Journ.  Soc.  Chem.  Ind.t  1892,  p.  500. 


LUBRICANTS.  321 

Castor  oil  itself  when  similarly  blown,  undergoes  analogous 
changes,  becoming  still  more  viscid,  and  acquiring  the  property 
of  being  miscible  with  hydrocarbons  (ordinary  castor  oil  is 
almost  insoluble  in  petroleum  hydrocarbons,  &c.) ;  accordingly, 
blown  castor  oil  is  often  spoken  of  as  "  soluble  castor  oil."  The 
same  term,  however,  is  sometimes  applied  to  the  oil  treated  with 
sulphuric  acid  (Turkey  red  oil). 

Oxygen  Process. — A  process  has  been  brought  out  under 
the  auspices  of  "Brin's  Oxygen  Co."  whereby  commercially 
pure  oxygen  (containing  90-93  per  cent,  of  actual  oxygen)  is 
used  instead  of  air  for  the  purpose  of  "boiling"  linseed  oil  for 
varnish  oil  and  linoleum,  and  similarly  blowing  other  oxidisable 
oils,  either  in  presence  of  a  small  quantity  of  driers,  or  without 
them.*  In  carrying  out  this  process  it  is  found  unnecessary  to 
blow  the  gas  through  the  oil ;  a  steam  jacketted  pan  is  provided 
capable  of  being  closed  by  a  cover,  and  containing  an  agitator 
consisting  of  vertical  rods  or  vanes  moving  round  horizontally. 
When  the  oil  to  be  treated  has  become  heated  nearly  to  100°  C., 
the  agitator  is  set  in  motion,  and  oxygen  led  in  to  the  space 
above  the  oil ;  the  splashing  oil  drops  present  a  large  absorbent 
surface,  so  that  the  oxygen  is  absorbed,  at  first  comparatively 
slowly  but  later  on  with  great  vigour,  so  that  although  a  rapid 
stream  of  gas  is  delivered  into  the  pan  it  is  absorbed  more 
rapidly  than  it  is  supplied,  producing  a  partial  vacuum.  As  the 
action  goes  on  the  oil  heats  greatly,  so  that  ultimately  it  becomes 
necessary  to  cool  the  jacket  by  admitting  water  into  it.  It  is 
claimed  that  the  oxidising  action  is  under  better  control  by  this 
treatment,  and  that  a  superior  result  can  be  effected  in  a  much 
shorter  time,  so  that  the  extra  cost  of  the  oxygen  gas  is  amply 
recouped. 

A  somewhat  similar  process  has  been  subsequently  patented 
by  E.  Opderbeck  f  for  making  ';  consistent  fish  fat,  train,  and 
other  oils,"  by  heating  them  to  90°-100°  C.,  and  then  intimately 
commingling  them  with  compressed  oxygen. 


MISCELLANEOUS   USES   OF   OILS,   FATS,  &c. 
MANUFACTURE  OF  LUBRICANTS. 

The  substances  employed  to  diminish  the  friction  between  sur- 
faces in  motion  relatively  to  one  another  are  of  very  various  kinds 
according  to  the  nature  of  the  mechanism,  £c.,  to  be  lubricated ; 
thus  for  watches  and  chronometers  on  the  one  hand,  and  railway 
axles  on  the  other,  widely  different  substances  are  respectively 

*  English  Patent  Specs.,  12,652,  1886;  18,628,  1889. 
t  English  Patent  Spec.,  24,153,  1892. 

_  21 


322  OILS,    FATS,    WAXES,    ETC. 

best  suitable ;    whilst  the  spindles  of  cotton  spinning  jennies, 
the  piston  boxes  of  steam  engines,  and  the  bearings  of  shafting 
generally,  represent  other  different  classes  of  moving  objects  for 
each  of  which  special  kinds  of  lubricants  are  requisite.    Formerly 
animal  and  vegetable  oils  and  fats  were  almost  exclusively  used 
for  lubricating  purposes,  the  finer  qualities  being  employed  for 
the  more  delicate  machinery  and  the  coarser  varieties  and  dirtier 
greases  for  the  greasing  of  cartwheels  and  similar  rough  purposes ; 
the  introduction  of  railway  travelling  and  the  extended  use  of 
machinery  of  all  kinds  led  to  the  modification  of  some  of  these 
materials  by  partial  saponification  with  lime  or  alkalies  so  as  to 
produce  an  imperfect  soap  containing  much  unsaponified  fat,  and 
to   the   admixture  with   them   of  more  or  less   viscous  hydro- 
carbons,   more     especially   the    "rosin   oils"    prepared    by   the 
distillation  of  rosin,  and  certain  higher  boiling  fractions  obtained 
in  the  treatment  of  petroleum  shale  oils,  coal  and  other  tars, 
and  similar  substances.     At  the  present  day  "  mineral  oils  JJ  of 
this  latter  kind  are  most  extensively  used,  either  alone  or  in 
combination  with  saponifiable  oils,  although  for  certain  special 
purposes  the  latter  are  still  preferable.     Obviously  only  those 
kinds  of  mineral  oil  are  available  that  do  not  readily  give  off 
inflammable  vapours  on  account  of  risk  of  fire,  and  the  drying 
up  of  the  lubricant  by  evaporation ;  moreover,  lighter  oils  of  this 
kind  have  not  sufficient  "  body,"  especially  for  heavy  machinery. 
Of  the  animal  oils,  sperm  oil  stands  pre-eminent,  neat's  foot  oil, 
tallow,  and  lard  oil  being  also  valuable  ingredients  largely  used, 
and  to  a  lesser  extent  whale  oil  and  various  fish  oils ;  whilst  olive 
oil,  palm  oil,  and  rape  oil,  and  to  a  lesser  extent  cotton  seed, 
sesame,  and  groundnut  oils,  &c.,  are  also  extensively  employed. 
In  all  such  cases  it  is  imperative  that  no  free  mineral  acid  should 
be  present,  as  otherwise  bearings,   (fee.,   are  apt  to  be  rapidly 
corroded  :  hence  oils  refined  by  acid  processes  (p.  259)  are  usually 
regarded  as  inadmissible  as  ingredients  in  first-class  lubricating 
oils,  unless  the  small  quantities  of  admixed  mineral  acid  have 
been   thoroughly  removed   by  a   subsequent  washing  with   an 
alkaline  fluid.    There  appears  also  to  be  good  reason  for  regarding 
the  presence  of  any  considerable  percentage  of  free  organic  acids 
as  objectionable  for  similar  reasons,  more  especially  in  the  case 
of  bearings  made  of  gun  metal  and  other  copper  alloys,  inasmuch 
as  in  presence  of  such  acids  the  copper  is  apt  to  become  oxidised, 
producing  corrosion  and  pitting  •  hence  oils  refined  by  alkaline 
treatment   are   preferable.      Cotton   seed   oil   thus    refined  (for 
the  purpose  of  removing  resin,  p.  260)  owes  much  of  its  value 
to  the  circumstance  that  it  is  practically  destitute  of  free  acids, 
which  to  a  great  extent  counterbalances  the  objection  to  its  use 
that,  as  a  considerable  proportion  of  drying  glycerides  is  present, 
it  possesses  a  rather  marked  tendency  to  absorb  oxygen  and 
thicken  or  "  gum  "  in  use. 


LUBRICANTS. 


323 


Animal  and  vegetable  oils  liable  to  contain  free  mineral  acids, 
may  be  conveniently  examined  as  to  the  presence  of  such 
constituents  by  the  process  described  on  p.  123;  or  the  oil 
may  be  well  shaken  up  with  distilled  water,  and  the  aqueous 
liquor  separated  and  examined,  whilst  the  amount  of  free  organic 
acids  may  be  determined  by  the  titration  method  described  on 
p.  116.  A  practical  test  as  to  the  relative  tendency  to  gumming 
is  to  place  equal  quantities  (drops)  of  the  oils  to  be  examined  on 
an  inclined  plane,  noting  the  distance  run  down  by  each  sample 
in  a  given  time,  and  the  time  required  before  the  oil  ceases  to 
run,  owing  to  the  increased  viscidity  through  oxidation ;  thus, 
the  following  figures  are  quoted  from  Appleton's  Dictionary  of 
Mechanics,  representing  the  run  of  each  oil  in  inches  : — 


Sperm  Oil. 

i 

Gallipoli 
(OJive)  Oil. 

Lard  Oil. 

Rape  Oil. 

Linseed 
Oil. 

Best. 

Common. 

1st  clay, 

32 

19 

10 

10-25 

14 

17-5 

2nd 

50 

45 

14 

10-5 

18 

18 

3rd 

53-5 

55 

18 

10-75 

19 

18 

4th 

54 

59 

18-5 

10-75 

19 

18-25 

5th 

54 

62 

19-5 

11-75 

19-25 

18-5 

6th 

54 

64 

20-5 

Still 

19-25 

Still. 

7th 

54 

67 

21 

... 

19-75 

... 

8th 

54 

67-5 

21-25 

Still. 

... 

9th 

68 

21-5 

... 

.... 

... 

Only  comparatively  small  amounts  of  unmixed  animal  and 
vegetable  fats  and  oils  are  used  alone  at  the  present  day  as 
lubricants ;  a  large  proportion  of  the  lubricating  agents  employed 
consist  of  hydrocarbons  only,  and  the  remainder  are  much  more 
frequently  mixtures  of  hydrocarbons  with  saponifiable  oils,  than 
substances  free  from  petroleum  and  rosin  oils,  and  such  like 
hydrocarbons. 

One  advantage  gained  in  the  case  of  such  mixtures  (apart  from 
cheapness)  is,  that  greasy  rags,  engine  waste,  &c.,  impregnated 
with  oil,  are  much  less  likely  to  heat  spontaneously  through 
oxidation  on  storage  (p.  132),  when  a  large  fraction  of  the  oil  is 
nonspontaneously  oxidisable  hydrocarbon,  than  would  be  the 
case  were  the  oil  wholly  composed  of  glycerides  and  such  like 
saponifiable  bodies. 

W.  Brink  finds  *  that  the  solution  of  a  small  quantity  of 
caoutchouc  in  a  lubricating  oil  consisting  of  mineral  hydrocarbons 
increases  its  viscosity  and  tends  to  prevent  gumming,  without 
introducing  any  corresponding  disadvantages.  Yarious  metallic 


*  English  Patent  Spec.,  17,163,  1889. 


324  OILS,    FATS,    WAXES,    ETC. 

soaps,  more  especially  aluminium  oleate,  are  often  added  to 
lubricating  oils  for  the  purpose  of  increasing  their  "  viscosity  ;" 
it  is  open  to  much  question,  however,  whether  such  an  addition 
really  adds  to  the  true  lubricating  power  of  the  composition,  and 
whether  it  should  not  be  looked  upon  simply  as  an  adulteration 
or  falsification  giving  a  fictitious  appearance  of  consistency  to 
the  oil. 

Lubricating  materials  other  than  pure  fats  and  oils,  may  be 
conveniently  classified  in  the  following  divisions  : — 

1.  Solid,  semisolid,  or  more  or  less  viscid  liquid  compositions 
of  animal  and  vegetable  oils  and  fats,  with  hydrocarbons  from 
petroleum  or  destructive  distillation  (shale  and  paraffin  oils),  or 
resin  oils  containing  little  or  no  inorganic  matters  intermixed. 

2.  Solid  or  semisolid  greases  containing  a  considerable  propor- 
tion of  saponaceous  matters   (alkali  or  lime  soaps  of  fatty  or 
resinous  acids),  together  with  more  or  less  additional  mineral  or 
organic  "  antifriction "  substances  (ground  mica,  steatite,  plum- 
bago, seaweed  jelly,  &c.) 

3.  Excessively  coarse   and   generally  dark    coloured   greases, 
consisting  of  byeproducts  of  various  industries,  the  refining  of 
which  is  too  costly  to  permit  of  the  materials  being  purified 
sufficiently  to  enable  them  to  be  utilised  in  other  ways — e.g., 
"  Yorkshire   grease,"   and   grease  from  engine  waste  (p.   236), 
containing  too  much  hydrocarbons,  &c.,  to  be  worth  distilling  for 
socalled  'k  stearine"  and  "oleine  "  (p.  277) ;  "dead  oils"  obtained 
in  coaltar  distillation ;  certain   kinds  of    "  foots "  obtained    in 
refining ;  pitchy  and  tarry  matters  of  various  kinds  not  available 
for  other  purposes,  and  so  on. 

Lubricants  of  the  first  class  include  "  engine  oils,"  "  engine 
tallow,"  and  similar  compositions  ;  "cylinder  oils"  for  lubricating 
the  piston  rods,  &c.,  of  steam  engines ;  "  machinery  oils "  for 
shafting,  bearings,  crank  axles,  and  the  like ;  "  spindle  oils  "  for 
quick  moving  light  machinery,  like  the  spindles  of  cotton 
spinning  jennies ;  watchmakers',  clock,  and  "  turret "  oils, 
specially  adapted  for  delicate  machinery  like  chronometers,  and 
not  liable  to  thicken  by  cold — and  a  large  variety  of  subordinate 
kinds.  Those  of  the  second  class  are  chiefly  compositions  used 
for  the  axle  boxes  of  locomotive  stock  (railway  trucks  and 
carriages,  &c.)  Coarse  greases  of  the  third  class  are  used  for 
cartwheels  and  rough  machinery,  such  as  the  pumping  engines 
employed  in  mining,  where,  through  the  circumstances  of  the 
case,  high  class  lubricants  are  unnecessary. 

Lubricants  of  the  First  Class — Lubricating  Oils. — The 
examination  as  to  the  practical  lubricating  value  of  materials 
and  compositions  of  this  class  is  rather  a  mechanical  than  a 
chemical  problem.  A  laboratory  test  greatly  relied  on  as  an 
indication  of  their  suitability  for  the  particular  purposes  in  view, 
is  the  determination  of  their  relative  efflux  rates  at  given  tern- 


LUBRICATING   OILS.  325 

peratures.  The  socalled  "viscosity"  values  thus  obtained  by 
means  of  one  or  other  of  the  various  forms  of  efflux  viscosimeter 
described  in  Chapter  v.  (or  better  still,  the  figures  obtained  by 
means  of  appropriate  large  scale  testing  machines,  &c.,  whereby 
the  conditions  obtaining  during  actual  use  can  be  nearly  imitated) 
are  generally  of  more  practical  value  to  the  consumer  than 
chemical  analyses  of  the  substances;  especially  when  coupled 
with  valuations  of  the  flashing  point  (p.  125)  and  the  degree  of 
volatility — i.e.,  the  rate  of  loss  by  volatilisation  on  heating  to 
known  temperatures.  On  the  Continent  considerable  stress  is 
often  laid  on  the  determination  of  the  "  congealing  point "  (vide 
p.  67).  For  an  outline  of  the  standard  methods  and  appliances 
in  use  for  the  purpose,  vide  Journ.  Soc.  CJiem.  Ind.,  1890,  p.  772. 
Lant  Carpenter  summarises  the  general  experience  gained  as 
to  the  character  and  behaviour  of  the  various  oils  used  for 
lubricating  as  follows  : — 

1.  A  mineral  oil  flashing  below  300°  F.  (149°  C.)  is  unsafe  on 
account  of  causing  fire. 

2.  A  mineral  oil  evaporating  more  than  5  per  cent,  in  ten 
hours    at    140°  F.  (60°  C.)    is    inadmissible,    as    the   evaporation 
creates  a  viscous  residue,  or  leaves  the  bearing  dry. 

3.  The  most  fluid  oil  that  will  remain  in  its  plabe,  fulfilling 
all  other  conditions,  is  the  best  for  all  light  bearings  at  high 
speeds. 

4.  The  best  oil  is  that  which  has  the  greatest  adhesion   to 
metallic  surfaces,  and  the  least  cohesion  in  its  own  particles  ;  in 
this  respect  fine  mineral  oils  are  1st,  sperm  oil  2nd,  neat's  foot 
oil  3rd,  and  lard  oil  4th. 

5.  Consequently,  the  finest  mineral  oils   are   best   for   light 
bearings  and  high  velocities. 

6.  The  best  animal  oil  to  give  "  body  "  to  fine  mineral  oils  is 
sperm  oil. 

7.  Lard  and  neat's  foot  oil  may  replace  sperm  oil  when  greater 
tenacity  is  required. 

8.  The  best  mineral  oil  for  cylinders  is  one  having  specific 
gravity   0-893    at   60°  F.    (15° -5  C.),    evaporating   point    550°  F. 
(288°  C.),  and  flashing  point  680°  F.  (360°  C.) 

9.  The   best   mineral   oil   for   heavy   machinery   has    specific 
gravity    0-880    at   60°  F.    (15° -5  C.),   evaporating  point   443°  F. 
(229°  C.),  and  flashing  point  518°  F.  (269°  C.) 

10.  The  best  mineral  oil  for  light  bearings  and  high  velocities 
has  specific  gravity  0-871  at  60°  F.  (15° -50.),  evaporating  point 
424°  F.  (218°  C.),  and  flashing  point  505°  F.  (262°  C.) 

11.  Mineral    oils    alone    are    not    suited    for    the    heaviest 
machinery  on  account  of  want  of  "body"   and   higher   degree 
of  inflammability. 

12.  Well  purified  animal  oils  are  applicable  to  very  heavy 
machinery. 


326  OILS,    FATS,    WAXES,    ETC. 

13.  Olive  oil  is  foremost  amongst  vegetable  oils,  as  it  can  be 
purified  without  the  aid  of  mineral  acids. 

14.  The  other  vegetable  oils  admissible,  but  far  inferior,  stated 
in    their    order    of   merit,  are    gingelly,  groundnut,  colza,   and 
cotton  seed  oils. 

15.  No  oil  is  admissible  which  has  been  purified  by  means  of 
mineral  acids. 

A.  H.  Allen  regards  the  following  characters  as  those  which 
should  be  taken  into  consideration  in  forming  an  opinion  as  to 
the  suitability  of  a  lubricating  oil  for  a  given  class  of  work  : — 

1.  The  viscosity  or  "body"  of  the  oil  at  the  temperature  at 
which  it  is  to  be  used. 

2.  The   temperature  at   which   the   oil   thickens   or  actually 
•solidifies. 

3.  The  flashing  point  or  temperature  at  which  the  oil  gives 
off  inflammable  vapours  in  notable  quantity. 

4.  The  volatility  or  loss  in  weight  which  the  oil  suffers  on 
exposure  in  a  thin  film  to  an  elevated  temperature. 

5.  The  "  gumming  "  character  or  tendency  of  the  oil  to  become 
oxidised. 

6.  The  relative  proportions  in  which  the  fatty  and  hydrocarbon 
oils  of  a  mixture  are  present. 

7.  The  proportion  and  nature  of  the  free  acid,  if  any,  in  the 
oil. 

8.  The  tendency  of  the  oil  to  act  on  metals. 

9.  The  presence  of  mineral  matters,  such  as  the  metallic  bases 
of  soaps,  &c. 

As  regards  the  degree  of  volatility  of  a  lubricating  oil,  J.  Carter 
Bell  considers  that  it  would  be  well  for  insurance  companies  to 
lay  down  a  hard  and  fast  rule  that  no  lubricating  oil  should  be 
used  in  any  mill  that  has  a  flashing  point  lower  than  350°  F. 
(177°  C.),  and  that  loses  more  than  5  per  cent,  in  twelve  hours  at 
140°  F.  (60°  C.) 

Lubricants  of  the  Second  Class — Carriage  and  Waggon 
Greases. — For  the  axle  boxes  of  railway  rolling  stock  a  peculiar 
kind  of  imperfect  soap  is  found  to  answer  well,  usually  made  by 
melting  tallow  and  palm  oil  together,  and  then  thoroughly  inter- 
mixing a  solution  of  sodium  carbonate  in  water,  for  which  purpose 
Morfit's  steam  twirl  (Chap,  xix.)  answers  well ;  or  a  boiled  palm 
oil  soap  is  dissolved  in  hot  water  and  thoroughly  intermixed  with 
melted  tallow,  the  emulsified  mass  being  then  cooled  so  as  to 
solidify. 

Richardson  <fe  Watts  *  give  the  following  receipts  as  furnishing 
compositions  of  this  kind  that  have  been  used  with  excellent 
results,  that  marked  "summer"  running  for  1,200  miles  : — 

*  Chemistry  applied  to   the  Arts  and   Manufactures,  vol.  i.,  part  iii. 
p.  744. 


LUBRICATING    GREASES. 


327 


w 

nter. 

Summer. 

Cwts. 

qrs. 

Ibs. 

Lbs. 

Cwts. 

qrs. 

Ibs. 

Lbs. 

Tallow,  . 

3 

3 

0 

=       420           4 

2 

0 

=        504 

Palm  oil, 

o 

2 

0 

=       280     i       2 

2 

0 

=         280 

Sperm  oil, 

0 

1 

7 

35           0 

0 

27 

=           27 

Soda  crystals, 
Water,  . 

1 
12 

0 
3 

14 

12 

=       126 
=    1,440 

1 

12 

0 
0 

8 

2G 

120 
=     1,370 

20 

2 

5 

2,301 

20 

2 

5 

2,301 

These  quantities  are  reckoned   to   give    1   ton  =  2,240  Ibs.    of 
grease,  allowing  about  2J-  per  cent,  for  loss. 

A.   H.   Allen   gives   the  following   composition   of  a   similar 
German  waggon  grease  : — 


Tallow,     . 
Palm  oil, 
Rape  oil, 
Caustic  soda, 
Water,      . 


24-6 
9-8 
1-1 
5-2 

59-3 

100-0 


The  following  composition,  containing  a  smaller  proportion  of 
saponaceous  matter,  has  been  patented  by  Hervieux  and  Bedard  * 
as  a  superior  form  of  axle  grease  : — 


Codfish  oil, 
Beef  tallow, 
Rosin, 
Soft  soap,  . 


24  parts. 
16     „ 

1  „ 

2  , 


A  somewhat  analogous  imperfect  lime  resin  soap  is  used  for 
railway  trucks  unprovided  with  axle  boxes,  carts,  and  waggons, 
and  similar  vehicles  ;  this  is  made  .by  elutriating  slaked  lime 
(by  stirring  up  with  water  and  running  the  "  milk  of  lime " 
through  a  succession  of  settling  tanks),  and  thoroughly  inter- 
mixing the  limemud  with  rosin  oil  in  the  cold  ;  the  resulting 
mass  is  often  intermixed  with  coarse  greases  and  other  sub- 
stances of  the  third  class,  and  sometimes  with  mineral  substances 
possessed  of  antifrictional  qualities  j  thus  the  following  com- 
position has  been  patented  by  A.  Purvis  f  as  an  improved 
lubricant  capable  of  resisting  unusually  high  temperatures  : — 


Japanese  tallow, 
Russian  tallow, 
Olive  soft  soap, 
Lard  oil, 
Castor  oil, 
Carbonate  of  lime, 
Carbonate  of  soda, 

*  English  Patent  Spec.,  4190,  1889. 
t  English  Patent  Spec.,  13,936,  I860 


2  cwt. 

3 

2 

108  Ibs. 
108 

10 

10 


328  OILS,    FATS,    WAXES,    ETC. 

The  mass  is  heated  and  well  intermixed,  with  the  addition  of 
J  cwt.  of  finely  pulverised  mica,  or  of  china  clay,  or  of  the  two 
together.  After  standing  twenty-four  hours  it  is  again  heated, 
and  20  Ibs.  of  zinc  oxide  added  ;  after  thoroughly  commingling 
the  mass  is  then  subjected  to  hydraulic  pressure  so  as  to  squeeze 
out  any  water  present. 

Numerous  analogous  mixtures,  consisting  essentially  of  tallow 
or  oil,  soap  of  some  kind,  and  solid  powdery  matter  (such  as 
graphite,  steatite,  or  sulphur)  are  in  use  as  antifriction  com- 
positions. 

Greases  of  the  Third  Class. — These  are  the  most  dangerous 
lubricating  materials  in  use  from  the  point  of  view  of  liability 
to  inflammation ;  refuse  coaltar  dead  oils,  anthracene  oils,  creosote 
oils,  &c.,  have  frequently  a  relatively  very  low  flashing  point,  and 
when  once  set  on  fire  are  not  easily  extinguished.  Such  com- 
pounds should  not  be  used  at  all  in  a  mill  or  similar  building 
where  great  damage  by  fire  might  be  occasioned. 

Analysis  of  Lubricating  Oils  and  .Greases. — Oils,  &c., 
consisting  wholly  of  organic  matters  will  obviously  leave  no 
ash  on  careful  incineration,  whereas  if  any  soapy  material  or 
other  inorganic  "  antifriction "  constituent  be  present,  more  or 
less  residue  will  be  left  when  a  known  weight  of  substance  is 
cautiously  heated  (e.g.,  in  a  platinum  dish)  and  the  residual 
carbon  burnt  off.  An  examination  of  this  residue  may  be  made 
as  regards  the  quantity  of  alkali  contained,  the  amount  of  lime, 
alumina,  steatite,  &c.,  present,  and  so  on. 

Organic  suspended  matters,  such  as  Irish  moss  or  seaweed 
jelly,  lime  or  other  soaps  insoluble  in  ether  or  petroleum  spirit, 
<fec.,  may  be  conveniently  sought  for  by  thinning  the  material 
with  the  solvent,  and  passing  through  a  weighed  filter,  finally 
washing  out  all  soluble  matters ;  the  residue  may  be  weighed,  a 
portion  incinerated  to  obtain  the  proportion  of  inorganic  matters 
present,  and  the  remainder  further  examined  as  may  seem 
requisite.  When  metallic  soaps  (alumina,  iron,  &c.)  are  present, 
the  metallic  basis  can  be  conveniently  removed  by  thining  the 
grease  with  ether,  &c.,  and  agitating  with  water  strongly  acidu- 
lated with  hydrochloric  acid. 

When  saponaceous  matters  are  present  (e.g.,  when  the  "foots" 
from  oil  refining  by  alkaline  processes  (p.  260)  are  used  as  in- 
gredients, or  when  lime  and  rosin  spirit,  or  soda  and  palm  oil, 
<fec.,  are  used,  as  with  certain  kinds  of  waggon  grease),  the 
methods  employed  in  soap  analysis  are  available  with  suitable 
modifications  ;  thus  the  total  alkali  present  may  be  conveniently 
found  by  shaking  with  ether  and  a  slight  excess  of  standard 
acid  (hydrochloric  or  nitric),  separating  the  watery  part  and 
back-titrating  the  excess  of  acid  not  neutralised.  By  adding 
phenolphthalein  to  an  alcoholic  solution  of  the  oil  or  grease, 
and  cautiously  dropping  in  standard  acid,  and  shaking  after  each 


LUBRICATING    OILS   AND    GREASES.  329 

addition,  the  amount  of  alkali  or  alkaline  earth  present  other- 
wise than  as  soap  may  be  at  least  approximately  determined  ; 
and  by  further  diluting  with  water,  adding  ether,  petroleum 
spirit,  carbon  disulphide,  or  other  convenient  solvent,  and  excess 
of  standard  acid,  the  total  alkali,  tfcc.,  may  be  determined  as 
above ;  whilst  after  separating  the  solution  of  oil  in  ether,  &c., 
the  fatty  and  resinous  acids  set  free  may  be  titrated  therein  in 
the  usual  way  (p.  116). 

Glycerides  (animal  and  vegetable  oils  and  fats)  and  liquid 
waxes  (sperm  oil,  &c.)  are  determined  as  with  ordinary  oils 
(p.  162) ;  after  neutralisation  of  free  fatty  acids  (or  alkalies) 
excess  of  standard  alkali  is  added  with  alcohol,  and  the  whole 
boiled  some  time  with  an  inverted  condenser  and  the  alkali  not 
neutralised  determined ;  the  product  diluted  with  water  and 
shaken  with  petroleum  spirit  gives  a  watery  solution  of  the  soap 
formed  by  saponification  of  the  glyceride,  from  which  the  con- 
tained fatty  acid  may  be  separated  and  subjected  to  examination; 
whilst  the  petroleum  spirit  contains  in  solution  the  hydrocarbons 
present  in  the  original  grease,  together  with  non-fatty  acid  oxi- 
dised matters,  such  as  cholesterol  from  woolgrease,  <fcc.,  the 
higher  alcohols  formed  by  saponification  of  sperm  oil,  and  the  like. 
When  requisite  these  may  be  further  examined  by  the  acetyla- 
tion  process  (p.  186). 

As  a  general  rule,  the  chemical  analysis  of  a  given  lubricant 
affords  very  little  information  as  to  its  suitability  for  any  parti- 
cular purpose  ;  but  certain  laboratory  determinations  are  often  of 
considerable  value,  more  especially  the  determinations  of  rate  of 
loss  of  weight  on  heating  to  given  temperatures  for  specified  times  ; 
of  the  efflux  "  viscosity  "  at  specified  temperatures  ;  and  to  a  lesser 
extent  of  the  specific  gravity.  The  "flashing  point"  and  the 
somwhat  higher  temperature  of  firing  ("ignition  point")  are  also 
important,  especially  with  mineral  oiis.  The  principal  chemical 
tests  of  practical  value  are  those  for  free  mineral  and  organic 
acids,  more  especially  the  former.  The  chief  utility  of  analysis 
in  the  case  of  lubricating  oils  is  to  decide  whether  they  are  of 
the  composition  stipulated  for  in  a  contract — e.g.,  as  to  containing 
a  given  percentage  of  sperm  oil  intermixed  with  hydrocarbons, 
and  so  on  ;  or  to  see  whether  otherwise  genuine — e.g.,  in  the  case 
of  rape  or  castor  oil,  as  to  whether  adulterated  with  other  sub- 
stances, such  as  cheaper  oils  or  hydrocarbons  ;  or  in  the  case  of 
blown  oils  whether  artificially  thickened  by  addition  of  soft 
soap,  aluminium  oleate,  rosin,  and  so  on. 

Occasionally  it  is  required  to  find  out  whether  rosin  oils  have 
been  admixed  with  mineral  oil  lubricants  ;  for  this  purpose  the 
glacial  acetic  test  described  on  p.  57  may  be  conveniently  used, 
rosin  oils  being  readily  soluble  in  that  solvent  whilst  mineral 
oils  are  practically  insoluble  therein. 

Rate    of  Absorption   of  Oxygen. —  According  to  O.   Bach 


330 


OILS,    FATS,    WAXES,    KTC. 


the  facility  with  which  a  lubricating  oil  absorbs  free  oxygen  is 
a  useful  measure  of  its  "gumming"  tendency.  By  sealing  up  in 
a  glass  tube  containing  100-125  c.c.  quantities  of  oil  of  from  3  to 
5  c.c.,  after  displacing  all  air  by  oxygen,  and  heating  for  ten 
hours  to  110°C.,  a  more  or  less  considerable  absorption  of  gas 
takes  place,  readily  determined  by  opening  the  sealed-up  end  of 
the  tube  under  water,  and  noting  the  amount  of  inrush.  Thus 
various  kinds  of  oils  gave  the  following  numbers  : — 


1  gramme  of  Valve  oil  (mineral) 
Valveoline 
Lubricating  oil 
Oleonaphtha 

socalled  "Cod  oil:"  sp.  gr.  0  963 
Olive  oil 
Rape  seed  oil 
Cotton  seed  oil 
Rosin  oil 


absorbed  O'l  c.c.  of  oxygen. 
0-45 
07 
8-6 
76-3 
144-0 
166-0 
111-0 
181-0 


Little  or  no  acidity  is  shown  by  the  water  sucked  in  with 
mineral  oils,  but  with  others  with  which  the  absorption  of 
oxygen  is  large,  a  strong  acid  reaction  is  manifest,  especially 
in  the  case  of  rosin  oil. 


TURKEY  RED  OILS. 

The  chemical  differences  between  the  two  kinds  of  oils  treated 
with  sulphuric  acid  known  under  the  name  of  "  Turkey  red  oils  " 
have  been  already  described  (p.  143,  et  seq.)*  In  the  practical 

*  Since  that  description  was  written  a  paper  by  P.  Juillard  has  appeared 
on  the  action  of  sulphuric  acid  on  olive  oil,  and  the  nature  of  olive  Turkey 
red  oil  (Journ.  Soc.  Chem.  Ind.,  1893,  p.  528,  from  Bulletin  Soc.  Ind., 
Mulhouse,  1892,  p.  413).  The  first  action  at  0°  to  5°  is  described  as  the 
direct  combination  of  one  and  of  two  molecules  of  sulphuric  acid  with  olein 
forming  mixed  glycerides,  containing  simultaneously  the  radicals  of  oleic 
and  oxystearosulphuric  acids,  and  respectively  indicated  by  the  formulae — 


O.CO.C17H34.0.  S03H 
C3H5<|O.CO.C17H33 
O.CO.C17H33 


and  C«H, 


O.CO.C17H34.  O.S03H 
O.CO.C17H34.O.S03H 
O.CO.C17H33 


By  the  further  action  of  sulphuric  acid,  these  give  rise  to  other  more 
complex  mixed  glycerides  containing  simultaneously  the  radicals  of  sul- 
phuric and  oleic  or  oxystearosulphuric  acids,  and  also  that  of  a  "  poly- 
merised "  oleo-oxystearic  acid,  viz. : — 

(O.CO.C17H34.O.CO.C17H33 
C3HJO.CO.C17H33 
(  0 .  S03H 

(  0  .  CO  .  C17H34  .  0  .  CO  .  C17H33 
and  C3H5  \  0  .  CO  .  C17H34  .  0  .  S03H 
(  0 . S03H 

Commercial  olive  Turkey  red  oil  chiefly  consists  of  the  sodium  salts  of  these 
acids  and  of  their  derivatives  and  products  of  decomposition  (oleic,  oxy- 


TURKEY    RED    OILS.  331 

manufacture  of  the  castor  oil  products  it  is  generally  considered 
indispensable  to  prevent  the  temperature  from  rising  materially 
above  35°  or  at  most  40°  C.,  otherwise  secondary  reactions  take 
place,  leading  to  evolution  of  sulphurous  acid,  and  production  of 
inferior  products.  The  oil  is  run  into  a  wooden  tank,  preferably 
lined  with  sheet  lead,  and  provided  with  cocks  at  different 
heights  to  facilitate  the  running  off  of  wash  liquors,  &c.  ;  the 
sulphuric  acid  is  then  gradually  run  in  with  continual  agitation, 
either  by  hand- worked  paddles  or  by  a  mechanical  agitator. 
Considerable  differences  in  the  practice  of  various  makers  occur 
in  this  stage  of  the  process,  the  precise  details  of  working  being 
usually  regarded  as  trade  secrets  ;  in  some  cases  the  acid  is  run  in 
at  one  operation,  more  especially  when  the  proportion  employed 
is  smaller;  in  others  part  added  at  one  time,  and  the  rest  at 
intervals ;  sometimes  half  being  added  one  dav,  and  the  other 
half  the  next  day.  The  proportion  of  acid  used  also  varies 
considerably/'5"  from  15  to  40  per  cent,  of  the  weight  of  oil  used. 
After  standing  14—24  hours,  a  solution  of  common  salt  is  run  in 
and  the  whole  well  agitated  with  the  object  of  removing  excess 
of  free  sulphuric  acid  not  converted  into  compound  acids,  glycerol, 
glycerosulphuric  acid,  and  such  like  substances  soluble  in  water, 
without  removing  the  soluble  compound  sulphuric  acids  formed, 
these  being  much  less  soluble  in  brine  than  in  plain  water.  If 
during  this  washing  the  liquor  become  much  heated,  considerable 
loss  is  brought  about  because  dilute  hydrochloric  acid  is  formed 
which  rapidly  hydrolyses  the  compound  acids  present ;  plain 
water  is,  therefore,  sometimes  used  for  a  first  washing,  and  brine 
or,  better  still,  sulphate  of  soda  solution  for  subsequent  ones.  A 
certain  amount  of  soda  or  ammonia  is  then  run  in  to  the  washed 
oil  and  well  admixed,  so  as  to  neutralise  part  (but  usually  not  all) 
of  the  free  acidity  ;  finally  enough  water  is  added  to  bring  down 
the  percentage  of  oleaginous  matter -present  to  the  requisite 
extent,  50  or  even  less  in  some  cases.  The  ultimate  product  is 
consequently  a  sort  of  emulsion  of  undecomposed  fatty  matter 
and  free  acids  disseminated  through  a  watery  solution  of  the 
soaps  formed  by  the  action  of  the  alkali  added  on  the  free  fatty 
acids  and  compound  sulphuric  acids  formed ;  if  properly  prepared 
so  as  to  contain  the  latter  in  sufficient  quantity,  castor  Turkey 
red  oil  can  be  diluted  with  water  without  allowing  oily  drops  to 
separate  until  after  standing  some  considerable  time ;  and  may 
be  dissolved  in  ammonia  and  diluted  with  water  without  becoming 
seriously  turbid  through  separation  of  oil,  &c.  If  much  precipi- 
tation is  visible  solid  fatty  glycerides  are  present,  due  to  adulter- 

stearic,  oleostearic,  oleo-oxystearic  acids,  &c. )  formed  during  the  process 
of  washing  out  the  uncombined  sulphuric  acid. 

For  a  summary  of  the  bibliography  of  the  chemistry  of  Turkey  red  oils 
vide  Journ.  Soc.  Chem.  Ind.,  loc.  cit. 

*  J.  A.  Wilson,  Journ.  Soc.  Chem.  Ind.,  1891,  p.  26;  1892,  p.  495. 


332  OILS,    FATS,    WAXES,    ETC. 

ation  of  the  original  castor  oil  with  rape  or  cotton  seed  oil, 
&c. 

According  to  P.  Loch  tin  *  the  risk  of  spoiling  the  product 
prepared  from  castor  oil  and  sulphuric  acid  by  overheating  is 
much  less  than  is  commonly  supposed,  firstly  because  no  decom- 
position involving  the  formation  of  sulphuric  acid  is  produced  at 
temperatures  not  exceeding  70°,  excepting  that  due  to  albuminoid 
impurities ;  and  secondly,  because  in  his  view  only  the  free  fatty 
acid  is  of  use  in  the  dyeing  process,  some  of  the  best  preparations 
only  containing  2  to  5  per  cent,  of  sulphuric  anhydride  (SO3)  per 
100  of  fatty  acids  (ricinoleosulphuric  acid  theoretically  corre- 
sponds with  a  ratio  of  80  parts  S03  to  298  of  ricinoleic  acid,  or 
27  per  100).  Moreover,  the  product  of  saponification  by  alkali 
(necessarily  containing  no  compound  sulphuric  acid)  gives  very 
fine  shades  in  practical  dyeing,  although  the  tendency  to  frothing 
causes  the  colour  to  be  a  little  uneven.  The  alkali  added,  he 
considers,  should  be  ammonia  and  not  soda  or  potash,  because  in 
printing  steam  colours  the  alkali  is  volatilised  and  the  free  fatty 
acid  left  on  the  cloth.  In  winter  20  to  30  parts,  and  in  summer 
15  to  20,  of  concentrated  sulphuric  acid  are  used  (in  Russia)  per 
100  of  castor  oil ;  about  one  half  of  the  acid  is  stirred  gradually 
into  the  oil  during  nine  hours  of  a  working  day  \  the  mixture  is 
allowed  to  stand  all  night,  and  the  next  day  the  rest  of  the  acid 
is  stirred  in  and  the  mixture  allowed  to  stand  until  a  sample 
taken  out  exhibits  a  clear  solution,  when  a  few  drops  are  shaken 
with  distilled  water  in  a  test  tube :  if  allowed  to  stand  too  long 
a  cloudy  fluid  is  obtained,  just  as  when  the  action  has  not  been 
sufficiently  prolonged.  At  the  proper  time,  an  equal  bulk  of 
cold  water  is  added  to  the  fluid,  when  the  oil  separates  and  floats 
on  the  diluted  acid  solution ;  if  a  larger  proportion  of  free  fatty 
acid  (hydrolysed  sulphuric  compounds)  is  desired,  hot  water  is 
used  instead  of  cold. 

Formerly  this  hydrolytic  decomposition  was  usually  regarded 
as  the  chief  thing  to  be  feared  and  avoided  in  manufacturing 
Turkey  red  oils  ;  but  recently  such  oils  have  been  placed  on  the 
market  under  the  name  of  "oxyoleates"  by  Messrs.  Schmitz  <fc 
Tcenges,  of  Heerdt  (Dlisseldorf),  in  the  preparation  of  which  the 
salted  out  fatty  acid  is  purposely  heated  to  105°  to  120°  C., 
whereby  practically  all  sulphur  is  eliminated  in  the  form  of 
sulphurous  and  sulphuric  acids. f  According  to  P.  Werner,! 
these  products  are,  for  certain  applications,  superior  to  the  usual 
Turkey  red  oils  containing  sulphurised  acids. 

Analysis  of  Turkey  Red  Oils. — In  order  to  hydrolyse  the 
compound  sulphuric  acids  present,  a  weighed  quantity  is  agitated 
with  about  twice  its  volume  of  saturated  brine,  and  about  one- 

*  Journ.  Soc.  Chem.  Ind.,  1890,  p.  498. 

t  English  Patent,  14,430,  1891. 

I  Journ.  Soc.  Chem.  Ind.,  1893,  p.  40. 


ANALYSIS    OF    TURKEY    RED    OILS.  333 

tenth  its  volume  of  strong  hydrochloric  acid,  whereby  hydrolysis 
is  speedily  brought  about ;  the  product  is  then  shaken  up  with 
ether,  the  ethereal  solution  evaporated  to  dryness,  and  the  residue 
purified  by  solution  in  alcohol  and  nitration  to  remove  saline 
matters,  and  evaporation  till  all  alcohol  is  driven  off  (J.  A. 
Wilson).  The  residue  is  examined  so  as  to  determine  the 
amount  of  unaltered  glycerides  present  along  with  the  free  acid 
by  the  ordinary  methods  described  on  pp.  116,  157.  The  pro- 
portion of  ricinoleosulphuric  acid  originally  present  is  ascer- 
tained by  determining  the  total  amount  of  barium  sulphate 
obtained  from  the  acid  brine,  and  subtracting  therefrom  the 
amount  present  as  ordinary  sulphate  obtained  by  agitating 
the  oil  with  brine  and  ether  in  the  same  way,  but  without  the 
addition  of  hydrochloric  acid.  Obviously  the  weight  of  com- 
pound sulphuric  acid  deduced  from  the  corrected  weight  of 
barium  sulphate  thus  obtained  will  be  very  different  according 
as  it  is  reckoned  as  ricinoleosulphuric  acid  or  diricinoleosulphuric 
acid  (p.  146),  233  parts  of  barium  sulphate  corresponding  with 
378  parts  of  the  first  and  with  658  of  the  second,  and  con- 
sequently with  518  parts  of  a  mixture  of  the  two  in  equivalent 
proportions.* 

Another  mode  of  determining  the  relative  proportions  of 
sulphurised  and  non-sulphurised  acids  present  is  to  titrate  with 
standard  alkali  twice,  using  litmus  as  indicator  in  one  case,  and 
phenolphthalein  in  the  other ;  the  sulphurised  acids  are  given 
by  the  first  titration,  and  the  others  by  the  difference  between 
the  two.  Scheurer  Kestner  recommends  ammonia  as  the  alkali, 
notwithstanding  the  uncertainty  of  the  indications  of  phenol- 
phthalein therewith. 

Juillard  f  condemns  this  method  of  examination  as  giving 
inaccurate  results,  in  the  light  of  his  own  more  recent  re- 
searches (supra;  vide  also  p.  147),  more  especially  when 
diricinolein  sulphuric  anhydride  is  present,  as  is  usually  the 
case.  He  considers  that  the  essential  determinations  are  those 
of  the  fatty  acids  in  the  usual  way,  and  of  sulphuric  acid  and 
glycerol  after  hydrolysis  of  the  oil  by  boiling  with  dilute 
hydrochloric  acid.  In  view  of  the  different  shades  yielded  in 
dyeing  and  printing  by  the  various  components  of  the  oil,  a 
determination  is  desirable  of  the  molecular  weights  of  the 
fatty  acids  present  in  the  soluble  and  insoluble  states.  This 
may  be  accomplished  by  Raoult's  method,  care  being  taken  to 
use  enough  water  to  bring  into  solution  the  whole  of  the 

*  402  was  found  by  Scheurer  Kestner  as  the  equivalent  weight  of  mixed 
compound  sulphuric  acids  formed  in  one  case,  480  being  the  corresponding 
value  of  the  non-sulphurised  acids  simultaneously  produced  (riciuoleic 
acid  =  298  ;  diricinoleic  acid  =  578). 

-\Journ.  Soc.  Chem.  hid.,  1892,  p.  357;  from  Bulletin  Soc.  Chim.,  Paris, 
1891,  6,  p.  638. 


334  OILS,    FATS,    WAXES,    ETC. 

soluble  acids.  As  usually  prepared,  Turkey  red  oils  contain 
some  45  or  50  per  cent,  of  oil  capable  of  being  separated 
by  means  of  hydrochloric  acid  and  brine,  the  balance  being 
water  and  small  quantities  of  saline  matter,  &c.  Of  the 
separated  oil  generally  about  one-fourth  consists  of  unaltered 
glycerides.  The  alkali  added  is  usually  insufficient  to  neutralise 
all  the  free  acid,  as  a  rule  only  about  one-third  being  neutralised. 
On  addition  of  water  and  ammonia  to  the  product  a  clear 
emulsion  or  solution  is  formed  if  solid  glycerides  are  absent ; 
but  a  more  or  less  turbid  fluid  on  account  of  precipitation  if 
these  are  present  through  use  of  adulterated  oil,  ttc. 

In  order  to  examine  Turkey  red  oil  (from  castor  oil)  for 
adulteration  with  cotton  seed  oil  and  other  glycerides,  J.  A. 
Wilson  recommends  (loc.  cit.  supra)  that  a  weighed  quantity  of 
oil  (100  grammes)  should  be  saponified  by  boiling  with  methy- 
lated spirit  (250  c.c.)  and  pure  caustic  potash  (20  grammes)  for 
an  hour,  with  inverted  condenser  attached ;  after  evaporating  off 
the  alcohol,  the  residue  is  dissolved  in  half  a  litre  of  water,  and 
the  soap  decomposed  with  a  slight  excess  of  sulphuric  acid,  boil- 
ing the  whole  for  an  hour.  To  avoid  bumping,  a  piece  of  pumice 
stone  coiled  round  with  platinum  wire  should  be  placed  in  the 
flask.  After  standing,  the  fatty  acids  are  collected  by  siphoning 
off  the  acid  liquid  through  a  filter,  and  washed  several  times  with 
hot  water,  and  then  dried  at  100°,  and  examined  further.  The 
specific  gravity  at  98°,  as  taken  with  a  Westphal  balance,  varies 
considerably  according  as  the  fatty  acids  are  derived  from  castor, 
olive,  or  cotton  seed  oil ;  thus — 

Castor  oil  acids,  .  .  .         0 "892  at  98°  C. 

Olive  oil  acids,  .  .  .         0'851  ,, 

Cotton  seed  oil  acids,    .  .  .         0'872  ,, 

The  fatty  acids  derived  from  pure  castor  Turkey  red  oil,  not 
sophisticated  with  any  other  oil,  do  not  deposit  more  than  traces 
of  solid  matter  at  15° -5,  whilst  much  more  is  obtained  with  olive 
oil,  and  still  larger  amounts  with  cotton  seed  oil.  The  melting 
points  of  the  latter  two  acids,  when  tested  by  the  capillary  tube 
pressure  method  after  solidification,  are — 

Cotton  seed  oil  acids,    .  .  .  44°  C. 

Olive  oil  acids,  ....         40°  C. 

The  neutralisation  numbers  of  the  fatty  acids  do  not  differ 
much — 

Castor  oil  acids,  .  .  .  180  to  184 

Olive  oil  acids,  ...  173  to  170 

Cotton  seed  oil  acids,    .  .  .  171  to  175 

The  iodine  number  of  the  castor  oil  acids  is  very  variable,  being 
dependent  on  the  age  of  the  castor  oil,  and  the  method  of  pre- 
paring the  Turkey  red  oil,  especially  the  amount  of  sulphuric 


ANALYSIS    OF    TURKEY    RED    OILS. 


335 


acid  used ;  so  that  no  indications  of  any  value  as  regards  adul- 
teration can  be  derived  by  its  means. 

The  acetyl  test,  on  the  other  hand,  gives  indications  that  are 
of  service  in  this  direction  :  the  fatty  acids  are  boiled  for  an  hour 
and  a  half  with  four-fifths  their  weight  of  acetic  anhydride  with  a 
reflux  condenser,  and  the  acetylised  product  washed  with  hot 
water  till  the  washings  are  neutral  to  delicate  litmus  paper.  A 
weighed  quantity  of  the  acetyl  product  is  then  exactly  neutralised 
with  alcoholic  potash  in  the  cold  (whereby  the  "  acetyl  acid 
number"  is  obtained,  p.  187);  excess  of  potash  is  then  added 
(about  1|  times  the  first  amount),  and  the  whole  boiled  half  an 
hour  to  saponify  acetyl  derivatives,  the  unneutralised  potash 
being  finally  titrated.  The  amount  of  potash  neutralised  during 
this  second  part  of  the  titration  (acetyl  number)  varies  consider- 
ably, according  as  pure  castor  oil  has  been  employed,  or  castor 
oil  admixed  with  olive  or  cotton  seed  oils ;  so  that  whether  the 
observed  "  acetyl  number  "  is  wholly  due  to  the  saponification  of 
acetyl  derivatives,  or  (as  seems  more  probable,  p.  189)  is  partly 
due  to  the  hydration  of  anhydrides  formed  by  the  action  of  acetic 
anhydride  on  fatty  acids,  in  any  case  it  affords  a  means  of 
detecting  adulterations ;  thus  Wilson  gives  the  following  aver- 
ages:— 


1 

1 

Acetyl  Acid 
Number. 

Acetyl  Number. 

Sum  (socalled 
"Acetyl  Saponifi- 
cation Number"). 

Castor  oil  maximum,    . 
,,          minimum,     . 
I  Olive  oil,       . 
|  Cotton  seed  oil,     . 

144-0 
149-2 
1587 
179-0 

143-4 
138-7 
106-3 
53-0 

287  '4 
287-9 
265-0 
232-0 

These  acetyl  numbers  are  considerably  higher  than  those  yielded 
by  the  fatty  acids  obtained  on  saponifying  olive  and  cotton  seed 
oils  not  treated  with  sulphuric  acid,  quoted  on  p.  188,  suggesting 
that  either  a  considerable  amount  of  oxystearic  acid,  or  some 
analogous  substance,  is  formed  by  the  action  of  sulphuric  acid  on 
olein  and  saponification  of  the  product ;  or  else  that  the  forma- 
tion of  anhydrides  under  the  influence  of  acetic  anhydride  takes 
place  more  readily  with  the  fatty  acids  obtained  after  treatment 
with  sulphuric  acid,  than  with  those  formed  by  the  saponification 
of  the  original  oils.* 

Hydrocarbons  (petroleum,  rosin  oils,  Arc.)  are  easily  detected 

*  In  all  probability,  the  modification  of  the  acetyl  test  proposed  by 
Lewkowitsch  (determination  of  "distillation  acetyl  number"  instead  of 
"titration  acid  number,"  pp.  190,  198)  would  give  better  results  than 
those  obtained  by  Benedikt  and  TJlzer's  method,  errors  due  to  formation, 
of  anhydrides  being  thus  eliminated. 


336  OILS,    FATS,    WAXES,    ETC. 

in  Turkey  red  oil  by  the  process  ordinarily  used  for  the  purpose 
described  on  pp.  119,  124. 


CURRIERS'  GREASE,   SOD   OILS,  AND   DEGRAS. 

During  certain  operations  for  tanning  and  currying  skins, 
various  forms  of  oil  and  grease  are  worked  into  the  skin 
mechanically,  and  the  excess  subsequently  removed,  partly  by 
pressure,  partly  by  the  emulsifying  and  saponifying  action  of 
alkaline  solutions.  When  these  fluids  are  decomposed  by  an 
inorganic  acid  an  oily  mass  results,  partly  consisting  of  free  fatty 
acids  and  partly  of  undecomposed  glycerides.  When  tallow  has 
formed  part  of  the  original  grease  or  "dubbin"  employed,  the 
resulting  recovered  grease  is  of  thicker  consistency  than  that 
obtained  when  only  liquid  oils  have  been  employed,  such  as  olive 
oil,  whale  or  cod  oil,  or  menhaden  oil.  The  greases  thus  obtained, 
or  regained  by  pressure  only,  are  sometimes  known  as  "  sod  oils  " 
or  "degras";  when  cod  oil  and  similar  substances  are  absorbed 
in  skins  and  exposed  to  the  air,  a  certain  amount  of  oxidation  is 
brought  about  rendering  the  regained  oil  even  better  for  use  than 
the  original  unoxidised  material ;  accordingly  it  is  sometimes  the 
practice  (more  especially  in  France)  to  prepare  sod  oil  (Moellon) 
for  currying  by  absorption  in  skins  used  solely  for  the  purpose, 
and  subsequently  wrung  out  again  after  sufficient  exposure  to 
air.  Part  of  the  good  effect  produced  by  sod  oil  and  grease  that 
has  been  already  used  previously  is  supposed  by  some  to  be  due 
to  the  presence  of  tanning  matters  therein  dissolved  out  from  the 
leather  and  contained  in  a  condition  peculiarly  adapted  to  the 
finishing  of  the  tanning  process  in  another  skin ;  others  believe 
that  the  beneficial  effect  is  at  least  partly  due  to  the  solution  in 
the  grease  of  nitrogenous  matters  not  affected  by  tanning  and 
their  subsequent  removal  by  squeezing  out  the  greasy  solution, 
especially  if  the  operation  is  done  hot.  The  recovered  degras  at 
any  rate  contains  more  or  less  nitrogenous  matter,  which  is  left 
undissolved  as  a  resinoid  mass  when  the  material  is  treated  with 
light  petroleum  spirit ;  further,  a  considerable  amount  of  oxyoleic 
acid  (or  some  similar  oxy  acid,  such  as  dioxypalmitic  acid)  is 
usually  present,  and  in  the  case  of  degras  made  from  train  oils, 
more  or  less  cetylic  alcohol  and  similar  bodies  produced  by  the 
hydrolysis  or  saponification  of  their  compound  ethers,  together 
with  cholesterol ;  the  presence  of  these  substances  enables  fatty 
matters  to  become  emulsified  with  water  and  thus  to  penetrate 
the  tissues  more  readily,  just  as  in  the  case  of  lanolin  applied  to 
a  living  skin  (infra).  * 

Artificial  degras  and  curriers'  greases  and  dubbin  are  prepared 

*  For  analyses  of  various  kinds  of  de"gras,  and  a  discussion  of  their  general 
nature,  vide  Journ.  Soc,  Chem.  Ind.,  1891,  p.  557 ;  1892,  p.  639. 


LANOLIN.  337 

by  intermixing  tallow  and  cod  oil  or  similar  materials,  red  oil 
(crude  oleic  acid  from  the  candle  factory,  Chap,  xvi.)  and  wool- 
grease  sometimes  entering  into  the  composition,  together  with 
neutral  soap,  or  imperfectly  made  soap  prepared  by  heating 
together  oil  with  an  amount  of  alkali  insufficient  to  saponify  it 
completely.  These  products,  however,  are  generally  regarded 
as  greatly  inferior  to  that  prepared  by  the  oxidation  of  cod  or 
other  fish  oils  in  contact  with  skins,  so  that  for  the  finer  kinds 
of  French  leather  only  the  latter  are  employed. 

Sod  oils  obtained  by  simple  pressure  from  skins  treated  with 
olive,  cod,  or  menhaden  oil  are  valuable  when  properly  refined 
for  the  lubrication  of  delicate  machinery  (clocks  and  watches,  &c.), 
not  being  liable  to  clog  and  thicken. 


MANUFACTURE   OF   LANOLIN. 

Wool,  as  cut  from  the  sheep's  back,  is  largely  impregnated 
with  a  greasy  material,  suint,  the  inspissated  perspiration  of  the 
animal  •  this  partly  consists  of  various  natural  potash  salts  and 
soaps  soluble  in  water,  partly  of  cholesterol  and  isocholesterol 
and  their  stearic  and  other  compound  ethers,  and  to  a  small 
extent  of  cerylic  cerotate,  and  other  waxy  organic  matters. 
When  solvent  processes  are  employed  for  dissolving  out  the 
grease  (e.g.,  by  means  of  ether  or  carbon  disulphide)  the  sub- 
stance obtained  by  distilling  off  the  solvent  is  a  tarry  brown 
mass  of  unpleasant  odour,  of  specific  gravity  at  15°  about  0-973, 
melting  at  near  40°,  sparingly  soluble  in  alcohol,  and  only  very 
difficultly  saponifiable,  as  the  cholesterol  ethers  are  compara- 
tively very  stable  ;  the  "  woolgrease "  thus  obtained  is  usually 
distilled  by  means  of  superheated  steam,  whereby  a  mixture  is 
produced  mainly  consisting  of  free  fatty  acids  and  cholesterol, 
from  which  "  wool  stearine  "  is  obtained  by  expression.  Methods 
for  cleansing  wool  by  means  of  grease  solvents  have  not  come 
largely  into  use  in  Britain,  it  being  usually  considered  that  the 
heating  requisite  to  remove  the  residual  solvent  from  the  wool 
does  more  injury  than  the  action  of  soap  in  the  ordinary  wet 
process  of  wool  scouring.  Opinions  on  this  point,  however,  are 
by  no  means  unanimous. 

On  the  Continent  wool  cleansing  by  means  of  solvents  has 
made  much  more  progress,  and  a  variety  of  different  forms  of 
apparatus  have  been  patented  in  which  the  use  of  ether,  fusel  oil, 
carbon  disulphide,  light  petroleum  spirit,  benzene,  &c.,  has  been 
claimed.* 

By  treatment  with  water,  fleeces  yield  a  solution  of  potash 

*  For  a  description  of  Singer  &  Judell's  arrangements  in  which  carbon 
disulphide  is  the  solvent,  ride  a  paper  by  Watson  Smith,  Journ.  Soc.  Chem. 
Ind.,  1889,  p.  24. 

22 


338  OILS,    FATS,    WAXES,    ETC. 

soaps  in  which  the  cholesterol  and  other  compound  ethers,  <tc., 
are  emulsified;  the  extraction  from  the  watery  product  thus 
formed  of  a  purified  emulsion  for  medicinal  purposes  was  de- 
scribed by  Dioscorides  in  the  first  century  A. P.,  under  the  name 
of  'OIOVKOS;  a  more  refined  preparation  of  the  kind  has  of  late 
years  been  somewhat  largely  employed  under  the  name  of 
lanolin.  To  prepare  this  material,  Braun  &  Liebreich  *  subject 
the  suds  in  which  fleeces  have  been  washed  (or  a  mixture  of 
woolfat  and  soap  water  forming  an  analogous  emulsion)  to  centri- 
fugal action,  whereby  a  separation  is  effected  somewhat  analogous 
to  that  produced  in  a  cream  separator  ;  watery  soap  solution 
flows  away,  whilst  a  soft  grease  along  with  solid  dirty  particles  is 
retained.  The  former  is  subjected  to  treatment  with  acids,  etc., 
for  the  recovery  of  the  fatty  acids  contained  in  the  soap 
(Chap,  xii.)  ;  the  latter  is  purified  by  kneading  with  water, 
melting,  and  filtration,  or  solution  in  appropriate  solvents, 
followed  by  further  kneading  with  water  until  all  soluble  im- 
purities are  washed  away.  The  purified  greasy  matter  thus 
obtained  possesses  a  remarkable  power  of  forming  a  soft  lard-like 
mass  by  the  intimate  commingling  of  water  and  grease  so  as  to 
form  a  stiff  semisolid  emulsion.  On  account  of  the  peculiar 
utility  of  this  product  as  a  vehicle  for  enabling  drugs,  etc.,  to  be 
passed  into  the  body  by  rubbing  on  the  skin  lanolin  impreg- 
nated with  the  desired  active  material,  and  its  use  as  an 
emollient  unguent,  either  alone  or  in  combination  with  other 
materials,  it  has  of  late  years  come  somewhat  prominently  before 
the  public ;  as  also  have  various  other  substances  differing  there- 
from in  110  essential  particulars  except  the  trade  name,  and  in 
possessing  varying  degrees  of  purity. 

Several  modifications  of  Braun  &  Liebreich's  centrifugal 
separation  process  have  been  subsequently  introduced.  In  one 
of  these,  calcium  chloride,  or  other  similar  salt,  is  added  to  the 
water  so  as  to  form  insoluble  lime  salts  or  other  metallic  soaps ; 
the  separation  of  the  grease  is  thus  facilitated,  whilst  by  means 
of  hot  acetone  the  cholesterol  ethers,  waxes,  etc.,  present  are 
subsequently  dissolved  out  from  the  soaps  ;  after  distillation 
of  the  solvent  the  residual  purified  woolgrease  is  treated  with 
oxidising  agents  to  remove  animal  odour  and  lighten  the  colour, 
and  is  then  kneaded  with  water  till  the  requisite  consistency 
is  attained.  Other  •  processes  of  a  fractional  solvent  character 
are  also  employed  to  separate  from  the  crude  "  anhydrous 
lanolin "  i*  some  of  the  waxy  ingredients,  and  thus  obtain  a 
product  consisting  principally  of  cholesterol,  isocholesterol,  and 
their  ethers,  and  in  consequence  better  adapted  to  form  a  semi- 
solid  emulsion  with  water,  suitable  as  an  unguent,  &c. 

Some    of   the   products    sent   into   the   market   and    sold   as 

*  English  Patent  Spec.,  4,992,  1882. 

t  Vide  Levinstein,  Journ.  Soc.  Chem.  Ind.,  18S6,  p.  579. 


LANOLIN.  339 

"purified  woolgrease,"  or  under  various  fancy  names,  are  of 
much  less  desirable  character  than  others.  Levinstein  gives  the 
following  tests  as  those  by  which  the  purity  of  commercial  lanolin 
may  be  ascertained  : — 

1.  If  2  to  3  grammes  of  lanolin  be  heated  with   10  c.c.  of  a 
30  per  cent,   caustic   soda   solution,  no  ammonia  must  be  dis- 
engaged. 

2.  10   parts   lanolin  heated  with    50   of  distilled  water  must 
yield  a  clear  oil.     Impure  lanolin  becomes  frothy  and  turbid. 

3.  If  oily,    the    lanolin    thus    separated   must   be    free    from 
glycerol. 

4.  If  rubbed  with  water  with  an  iron  spatula  on  a  ground 
glass  plate,  the  oil  must  be  capable  of  taking  up  at  least  its  own 
weight  of  water,  forming  a  sticky  and  paste-like  mass  ;  if  impure, 
the  mass  will  have  a  soap-like  smoothness,  and  will  not  adhere 
to  the  spatula. 

Langbeck  *  describes  the  following  process  for  preparing  a 
purified  lanolin  : — The  wool  is  washed  twice  in  water  at  a 
temperature  not  exceeding  110°  F.,  and  dried  by  pressure 
or  centrifugal  action,  whereby  soluble  potash  salts  are  mostly 
removed ;  the  residual  wool  is  then  scoured  with  a  mix- 
ture of  potash  ley  and  olive  oil,  whereby  all  the  "woolfat'' 
is  removed  and  the  wool  thoroughly  cleansed.  The  watery 
emulsion  is  evaporated  and  treated  with  alcohol  of  40  to  60  per 
cent.,  which  dissolves  out  potash  soaps,  .leaving  behind  crude 
"woolfat,"  purified  by  solution  in  benzene  or  carbon  disulphide, 
filtration,  and  distillation  of  the  solvent.  The  product,  after 
further  purification  and  decolorisation  with  animal  charcoal 
(preferably  "  prussiate  waste  "),  and  subsequently  with  peroxide 
of  hydrogen,  produces  an  excellent  white  basis  for  pomades, 
ointments,  &c.,  containing  20  to  30  per  cent,  of  mechanically 
intermixed  water.  The  unpurified.  woolfat  forms  a  valuable- 
lubricant  and  leather  grease. 

A.  Seibel  has  recently  introduced  a  sulphurised  lanolin  f  for 
medicinal  and  other  purposes  prepared  by  heating  lanolin  to 
120°  C.,  with  about  20  per  cent,  of  flowers  of  sulphur,  whereby 
most  of  the  sulphur  is  dissolved ;  after  allowing  to  subside,  the 
supernatant  sulphur-containing  liquid  is  poured  off  and  heated 
to  230°,  whereby  much  sulphuretted  hydrogen  is  formed,  together 
with  the  sulphurised  lanolin  ;  like  ordinary  lanolin,  this  mixes 
freely  with  water  without  separation,  forming  a  soft  semisolid 
emulsion. 

*  Journ.  Soc.  Chem.  Intl.,  1S90,  p.  356. 
t  German  Patent,  No.  56,49]. 


340  OILS,    FATS,    WAXES,    ETC. 

CHAPTER    XV. 
ADULTERATION  OF  OILS  AND  FATS,   &c. 

THE  adulterations  mostly  practised  in  the  case  of  oils  and  fats, 
&c.,  may  be  broadly  divided  into  two  classes — viz.,  (1)  those 
where  some  weight-giving  ingredient  is  added  of  wholly  foreign 
nature,  as  where  an  undue  proportion  of  water  is  mechanically 
admixed  with  soft  fats,  such  as  butter  and  lard,  or  where  starchy 
matters  are  added  to  the  latter  substance  ;  and  (2)  those  where 
the  adulterant  is  a  lower  priced  substance  of  tolerably  similar 
nature,  as  where  cotton  seed  oil  is  admixed  with  olive  oil,  hemp 
seed  oil  with  linseed  oil,  or  oleomargarine  with  cow's  butter.  In 
some  cases  mineral  hydrocarbons  (petroleum  distillates)  or 
destructive  distillation  oils  (paraffin  oils,  rosin  oil,  &c.)  are 
admixed  with  animal  and  vegetable  oils;  or  substances  largely 
consisting  of  unsaponifiable  matters  derived  from  woolgrease, 
&c.,  with  tallow  and  similar  saponifiable  solid  fats  ;  here  the 
nature  of  the  adulteration  is  rather  of  the  first  class  than  of  the 
second,  inasmuch  as  by  appropriate  processes  the  adulterating 
impurity  may  (to  a  greater  or  lesser  extent)  be  analytically 
separated  from  the  material  examined,  and  directly  determined 
quantitatively ;  whereas  when  two  closely  similar  natural  oils, 
<fec.,  are  admixed,  in  most  cases  it  is  difficult,  if  not  impossible,  to 
effect  any  quantitative  separation  of  constituents  whereby  the 
-extent  of  the  admixture  can  be  directly  determined,  although  in 
many  cases  the  fact  of  the  admixture,  and  some  rough  idea  of 
its  extent,  can  be  arrived  at  by  indirect  means — e.g.,  by  the 
alteration  in  the  melting  point  of  the  mixed  fatty  acids  obtain- 
able on  saponification,  or  the  increase  (or  decrease)  in  the  iodine 
number  or  the  saponification  equivalent ;  or  by  the  production 
•  of  some  particular  colour  change  with  a  given  chemical  reagent, 
not  shown  by  the  natural  unadulterated  oil,  &c. 

In  most  cases  of  the  kind,  moderate  certainty  can  only  be 
ensured  by  making  comparison  tests  side  by  side  with  the 
substances  examined,  and  with  known  mixtures  of  pure  oils,  &c. ; 
and  here  a  great  difficulty  is  at  once  encountered  in  obtaining 
•standard  samples  of  pure  materials.  In  many  instances  this  can 
only  be  done  satisfactorily  by  preparation  of  the  standards  in  the 
laboratory  itself — e.g.,  by  expressing  hand-picked  samples  of 
seeds,  &c.,  so  as  to  ensure  that  the  seeds  themselves  shall  not  be 
mixtures  of  various  kinds,  and  the  oils  extracted  shall  be  free 
from  all  other  sophistications.  Even  with  all  possible  care  in 
preparing  pure  substances  for  comparison,  there  still  remains  a 
certain  amount  of  possibility  of  error,  owing  to  the  natural 


ADULTERATION    OF    OILS,    FATS,    ETC.  341 

fluctuations  brought  about  by  differences  in  the  soil  and  climate, 
the  degree  of  cultivation,  and  similar  causes.  Accordingly,  the 
analytical  detection  of  adulteration  in  oils  and  fats,  <fec.,  not  only 
depends  for  the  most  part  on  very  different  principles  from  those 
involved  in  mineral  analysis,  e.g.,  for  metals,  but  also  is  a  matter 
permitting  of  much  less  quantitative  certainty. 

The  methods  adopted  in  testing  commercial  samples  of  oils, 
fats,  &c.,  necessarily  vary  with  each  substance  examined,  but  in 
general  consist  of  a  suitable  selection  from  the  various  methods 
above  described,  based  on  the  physical  and  chemical  properties 
of  the  oils,  £c.  ($§  2  and  3) ;  more  especially — 

The  physical  texture,  colour,  taste,  and  odour  of  the  sub- 
stance examined. 

The  effect  on  polarised  light,  and  the  refractive  index. 
The  specific  gravity  of  the  substance,  or  of  the  fatty  acids 

thence  obtainable. 

The  fusing  and  solidifying  points  of  these  fatty  acids. 
The  solubility  in  various  solvents. 
The  efflux  velocity  at  various  temperatures. 
The  value  of  the  "  free  acid  number." 
The  percentage  of  unsaponifiable  matters  present  (including 

water,  suspended  substances,  and  inorganic  matters). 
The  nature  of  the  elaidin  formed,  and  its  degree  of  con- 
sistency. 
In  the  case  of  drying  oils,  the  result  of  tests  of  rate  of 

inspissation  through  oxygen  absorption. 

The   effect   of    qualitative    reagents    in    producing    colour 

reactions  (nitric  acid,  sulphuric  acid,  zinc  chloride,  &c.) 

The  degree  of  heat  evolution  on   mixture  with  sulphuric 

acid. 
The  nature  and  consistency  of  the  product   formed  with 

sulphur  chloride. 
The  quantitative  result  of  Kcettstorfer's  test  (sapoiiification 

equivalent). 
„  „  Hehner's     test     (insoluble     acid 

number). 
„  „  Reichert's     test     ( volatile     acid 

number). 

„  „  Hiibl's  test  (iodine  number). 

„  „  Benedikt  and  Ulzer's  test  (acetyl 

number). 

The  results  of  various  special  tests  applicable  in  certain 
particular  cases. 

The  following  particulars  respecting  the  normal  properties  of  a 
few  typical  oils  and  fats,  &c.,  and  the  effect  thereon  of  various 
adulterations,  will  serve  as  illustrations  of  the  methods  usually 


342  OILS,    FATS,    WAXES,    ETC. 

adopted  in  practice ;  for  more  full  details,  and  for  particulars 
respecting  other  substances,  analytical  treatises  specially  dealing 
with  the  subject  must  be  consulted.*  The  methods  of  analysis 
applicable  in  the  case  of  grease  recovered  from  suds  have  been 
already  discussed  in  Chap,  xn.,  and  those  employed  in  the  case 
of  certain  manufactured  oils,  &c.  (Turkey  red  oils,  butter  sub- 
stitutes, lubricants,  &c.),  in  Chap.  xiv.  ;  soap  analysis  generally 
is  dealt  with  in  Chap.  xxi. 

As  regards  the  general  principles  of  detection  of  adulteration, 
it 'is  to  be  borne  in  mind  that  the  object  of  sophistication  is 
essentially  to  sell  a  cheaper  article  at  the  price  of  a  more  costly 
one,  by  admixing  the  former  with  the  latter ;  hence  the  relative 
price  of  different  kinds  of  oils  and  fats,  &c.,  at  any  given  time, 
largely  affects  the  question  as  to  whether  certain  kinds  of 
adulteration  are  likely  to  be  practised  or  not.  Although  con- 
siderable variations  in  prices  necessarily  occur  in  the  market 
from  time  to  time,  still  it  is  possible  to  draw  up  a  rough 
classification  of  oils,  tfec.,  according  to  their  relative  values  when 
genuine.  The  following  list  is  given  by  A.  H.  Allen  (on  the 
authority  of  Mr.  T.  Duggan),  indicating  the  usual  order  of  price, 
subject  to  market  fluctuations  : — 

1.  Olive  oil.  t/11.  Colza  and  rape  oil. 

2.  Sperm  oil.  12.  Seal  oil. 

3.  Neat's  foot  oil  (genuine).  13.  Niger  seed  oil 
(  Bottlenose  oil.  14.  Linseed  oil. 

4  to  6.  j  Lard  oil.  15.  Whale  oil. 

(  Castor  oil.  16.  Cotton  seed  oil. 

7.     Cod  oil.  17.  Menhaden  oil. 

>-   (  Arachis  oil.  18.  Japan  fish  oil. 

•  8  to  10.  j  Sesam«5  oil.  ^    ]  9.  Mineral  oils. 

.(  Poppy  seed  oil.  20.  Rosin  oil. 

Olive  Oil. — The  natural  variations  in  the  quality  of  genuine 
oil  of  olives  are  much  less  marked  than  might  a  priori  be 
expected,  considering  the  wide  range  of  country  over  which  the 
olive  is  grown  for  the  purpose  of  oil  production,  and  the  number 
of  varieties  that  have  been  induced  by  centuries  of  cultivation 
in  different  climates  and  on  different  soils  of  the  different  species 
of  Olea.  Thus  0.  europcea  (var.  sylvestris)  was  alluded  to  by 
Dioscorides  as  a  thorny  tree  growing  wild  ('EXa/a  aypta] ;  but 
losing  its  thorns  by  cultivation  (like  the  sloe  bush,  the  parent  of 
the  garden  plums),  giving  the  variety  0.  europoea  (var.  sativa) 
or 'EA«/a  r^Mtpa;  which  again  has  been  the  parent  of  numerous 
distinct  kinds  of  olive  trees  producing  fruit  of  very  different 
sizes;  thus  the  socalled  "French"  olive  of  the  present  day  is 
much  smaller  than  the  "Spanish"  olive.  Apart,  however,  from 
these  subspecies  of  0.  europcea  grown  in  Greece,  Phoenicia, 

*  E.g.,  Allen's  Commercial  Organic  Analysis;  Benedikt's  Analyse  der 
Fette  und  Wachsarten ;  the  Analyst,  passim,  &c. 


OLIVE    OIL.  343 

Palestine,  and  the  south  of  Europe  since  the  commencement  of 
the  historic  period,  and  thence  introduced  and  acclimatised  into 
such  parts  of  America,  Australia,  and  elsewhere  as  possess  suit- 
able soils  and  climates,  other  oil-bearing  species  are  utilised  in 
other  countries — e.g.,  0.  ferruginea  (0.  cuspidata)  in  Afghanistan 
and  other  Himalaya  regions,  and  0.  capensis  at  the  Cape  of  Good 
Hope. 

Even  with  the  best  known  southern  European  varieties,  notable 
differences  in  the  quality  of  the  oil  extracted  are  found  to  exist 
according  to  circumstances,  more  especially  according  as  the  fruit 
has  thoroughly  ripened  on  the  trees,  or  has  been  plucked  before 
quite  ripe  and  stored;  and  according  as  the  oil  has  been  extracted 
by  gentle  pressure  in  the  cold,  or  by  hot  pressure,  especially  when 
accompanied  by  grinding  processes  whereby  the  stones  are  also 
broken  up  and  expressed :  indeed  the  differences  in  quality  due 
to  these  causes  appear  to  be  quite  as  strongly  marked  as  those 
due  to  soil,  climate,  and  degree  of  cultivation.  The  finest 
qualities  of  all  are  obtained  by  handpicking  olives  from  the  trees, 
selecting  those  not  over  ripe,  but  ripe  enough  to  allow  oil  to 
exude  slightly  on  gentle  pressure  between  the  finger  and  thumb, 
and  pressing  very  gently  by  hand  in  cloths :  the  "  virgin  oil " 
thus  produced  is  subsequently  agitated  with  water,  and  allowed 
to  stand  so  as  to  remove  mucilaginous  matter,  the  purified  oil 
being  skimmed  off.  A  slightly  inferior,  but  still  fine,  grade  of 
oil  is  obtained  by  crushing  ripe  olives  (preferably  with  edge- 
stones,  but  without  breaking  up  the  olive  kernels),  and  then 
pressing  cold  with  comparatively  little  pressure.  The  residual 
marc  (known  in  Italy  as  Sanza  or  Nocciulo)  is  broken  up,  stirred 
with  boiling  water,  and  then  pressed  again  with  somewhat 
stronger  pressure ;  the  second  marc  (Buccia)  is  then  ground 
again  with  heavier  millstones  so  as  to  crush  the  olive  stones 
(if  this  were  not  done  at  the  first. crushing),  and  is  then  again 
stirred  up  with  boiling  water  and  subjected  to  the  heaviest 
pressure  attainable  with  the  appliances  used  :  in  small  mills 
these  are  usually  rough  screw  presses  (p.  200,  et  seq.),  but  in  larger 
ones  hydraulic  presses  are  employed  (p.  207,  et  seq.)  Finally, 
the  residual  oil  (several  per  cents.)  is  extracted  from  the  marc 
by  means  of  carbon  disulphide  or  other  solvents  (p.  231).  The 
details  of  the  processes  used  for  extracting  olive  oil  vary  widely 
in  different  districts  and  countries ;  thus  in  some  establish- 
ments the  stones  are  separated  from  the  pericarp  and  the  two 
treated  separately ;  a  superior  oil  is  thus  obtained  from  the 
pulp,  whilst  "  olive  kernel  oil "  is  extracted  from  the  stones  by 
grinding  them  to  a  coarse  meal  and  then  pressing  or  treating 
with  carbon  disulphide,  tfec.  Excepting  in  being  darker  coloured 
and  more  unpleasantly  smelling,  the  oil  thus  obtained  is  said  not 
to  differ  materially  from  the  lower  grade  oils  obtained  from  the 
fruit  pulp  ;  it  often  contains  a  large  percentage  of  free  fatty  acids 


344  OILS,    FATS,    WAXES,    ETC. 

rendering  it  more  readily  soluble  in  alcohol  than  ordinary  olive 
oil,  thus  resembling  the  "  huiles  tournantes  "  derived  from  the 
pulp  (infra). 

In  this  kind  of  fashion  several  qualities  of  olive  oil  are  ulti- 
mately obtained,  more  especially  "virgin"  and  "salad"  oils  of 
finest  flavour,  generally  greenish  through  presence  of  chlorophyll, 
and  of  specific  gravity  near  to  '916  at  15° ;  "huiles  d'enfer,"  *  or 
somewhat  lower  grades  of  inferior  flavour  (sometimes  with  more 
or  less  marked  acrid  aftertaste  and  disagreeable  odour) ;  "pyrene" 
and  "  sulphocarbon "  oils  (the  former  obtained  by  hot  pressing 
and  the  latter  extracted  by  carbon  disulphide  or  other  solvent) 
generally  unfit  for  edible  purposes,  brownish  yellow,  and  of  specific 
gravity  -920  to  -925  at  15°;  and  "huiles  tournantes"  obtained 
from  more  or  less  fermented  stored  fruit,  and  in  consequence 
considerably  rancid,  and  containing  large  amounts  (25  to  30  per 
cent.)  of  free  fatty  acids.  The  denser  varieties  deposit  solid 
matters  (mostly  palmitin)  on  chilling  somewhat  sooner  than  the 
lighter  ones. 

The  total  acid  number  of  various  grades  of  olive  oil  has  been 
found  by  different  authorities  to  lie  between  185  and  206, 
corresponding  with  the  saponification  equivalent  272  to  303  ;  the 
better  grades,  however,  generally  furnish  a  total  acid  number 
near  to  191  (saponification  equivalent  294),  and  an  iodine  number 
near  to  83.  f  Any  considerable  addition  of  rape  oil  would  raise 
the  saponification  equivalent  materially,  whilst  admixture  with 
poppy  seed  oil,  and  to  a  lesser  extent  with  sesame,  cotton  seed, 
and  rape  oils,  distinctly  increases  the  iodine  number.  Maumene's 
test  (p.  147)  indicates  a  smaller  degree  of  heat  evolution  on 
mixing  with  sulphuric  acid  in  the  case  of  olive  oil  than  with 
most  other  oils  ;  so  that  by  making  comparative  experiments 
with  pure  olive  oil  and  the  substance  examined  side  by  side, 
indications  of  want  of  purity  are  obtainable ;  lard  oil,  however, 
gives  about  the  same  heat  evolution  as  olive  oil.  Sophistication 
with  arachis  oil  is  moderately  easily  detected  thus,]:  although 
many  other  tests  fail  to  show  its  presence. 

*  Socalled  because  the  oil  (mixed  with  water  to  separate  mucilage  by 
standing)  is  stored  in  large  underground  tanks  or  reservoirs  so  as  to  avoid 
exposure  to  air  as  much  as  possible. 

t  Olive  oil  usually  consists  of  one-fourth  glycerides  of  solid  saturated 
acids  (palmitic,  &c. ),  and  three-fourths  liquid  glycerides,  mostly  oleiii. 
This  composition  would  correspond  with  an  iodine  absorption  of  about  67  ; 
the  somewhat  higher  values  usually  found  consequently  suggest  the  presence 
of  a  small  quantity  of  linolic  acid.  In  confirmation  of  this,  Hazura  and 
\GriIssner  have  obtained  small  quantities  of  sativic  acid  (p.  128)  from  the 
products  of  oxidation  of  the  fatty  acids  of  olive  oil. 

+  Renard's  test  for  groundnut  oil  is  said  by  A.  H.  Allen  to  be  sufficiently 
delicate  to  indicate  clearly  an  admixture  of  10  per  cent,  of  that  substance 
with  olive  oil,  although  failing  with  only  4  per  cent.  The  small  quantity 
of  arachin  naturally  contained  in  olive  oil  does  not  materially  interfere. 
The  oil  to  be  examined  is  saponified  and  the  fatty  acids  separated  and 


ADULTERATION    OF    OLIVE    OIL. 


345 


Admixture  with  heavier  oils,  such  as  cotton  seed  oil,  tends  to 
raise  the  specific  gravity;  whilst,  conversely,  addition  of  rape  oil 
tends  to  lower  it ;  thus  Souchere  gives  the  following  table  in- 
dicating the  effect  of  such  admixtures  on  the  relative  density  at 
15°  of  pure  olive  oil : — 


Specific  Gravity 

Percentage  Added. 

Oil. 

at  15s  of  Pure 
Oil. 

10 

20 

so 

40 

50 

Olive,    .     . 

•9153 

Colza,   .     . 

•9142 

•91519 

•91508 

•91497 

•91486 

•91475 

Sesame, 

•9225 

•91602 

•91674 

•91741 

•91818 

•91890 

Cotton  seed, 

•923 

•91607 

•91684 

•'J1761 

•91838 

•91915 

Arachis,    . 

•917 

•91547 

•91564 

•91581 

•91598 

•91615 

The  elaidin  test  (p.  137)  serves  to  distinguish  adulteration 
with  many  oils  giving  soft  elaidins  ;  a  distinct  softening  of  the 
product  as  compared  with  that  obtained  with  pure  oil  treated 
side  by  side  is  noticeable  when  only  a  few  per  cents,  of  poppy 
seed  or  linseed  oil  are  present,  and  with  somewhat  larger 
proportions  of  cotton  seed,  rape  seed,  or  sesame  oils  ;  moreover, 
the  elaidin  formed  with  pure  olive  oil  is  nearly  colourless  or  pale 
yellow,  whereas  much  darker  tints  are  generally  produced  with 
adulterated  oils  ;  based  on  which  property  are  numerous  modifi- 
cations of  the  nitric  acid  test  proposed  by  various  observers  for 
the  purpose  of  examining  olive  oil. 

Examination  of  the  cohesion  figure  (p.  48),  formed  when  oil 
is  placed  on  water,  has  been  recommended  by  Tomlinson  as  a- 
useful  test  of  the  purity  of  olive  oil.  A  drop  of  oil  is  allowed  to 
fall  gently  on  the  surface  of  pure  water  contained  in  a  chemically 
clean  basin  of  sufficiently  large  size,  at  a  temperature  not  below 
15°C.;  with  pure  olive  oil  the  drop  slowly  spreads  out  into  the- 
shape  of  a  large  disc  with  slightly  recurved  edges  ;  little  spaces 
shortly  appear  round  the  edge,  the  film  commencing  to  retract 
again,  so  that  the  edge  resembles  a  string  of  beads.  The  spaces 
between  the  beads  soon  open  out  more,  and  the  edge  becomes 
toothed  ;  portions  become  detached,  reuniting  themselves  in  some 

dissolved  in  five  parts  of  rectified  spirit,  and  precipitated  with  alcoholic 
lead  acetate  ;  or  the  oil  is  directly  saponified  with  litharge  by  boiling  with 
that  substance  and  water.  The  resulting  lead  soaps  are  agitated  several 
times  with  ether  to  dissolve  out  lead  oleate  (hypogaeate,  &c. ).;  the  residual 
lead  stearate,  palmitate,  and  arachate  are  decomposed  by  hot  dilute  hydro- 
chloric acid,  and  the  fatty  acid  cake  formed  on  cooling  and  standing,  dis- 
solved in  five  parts  of  hot  rectified  spirit  per  one  of  original  oil.  On  cooling, 
crystals  of  arachic  acid  arc  deposited  if  earthnut  oil  were  originally  pre- 
sent ;  from  the  weight  of  these,  corrected  for  solubility  in  the  mother 
liquors,  an  approximate  notion  of  the  proportion  of  earthnut  oil  present  can 
be  deduced,  on  the  assumption  that  100  parts  of  this  oil  correspond  with 
five  of  arachic  acid. 


346  OILS,    FATS,    WAXES,    ETC. 

places  to  the  main  oil  film  enclosing  polygonal  spaces  bounded 
by  fine  beads,  and  covered  by  a  dew  of  oil  so  fine  as  to  be  visible 
only  with  difficulty.  About  35  seconds  are  requisite  for  the 
entire  succession  of  changes.  With  sesame  oil  the  film  first 
formed  soon  begins  to  contract  again,  ultimately  forming  a  figure 
consisting  of  a  central  spot  with  distinctly  marked  rays,  between 
which  other  smaller  rayed  spots  appear,  the  whole  resembling  a 
spider's  web  loaded  with  dew ;  about  60  seconds  are  required  to 
complete  these  changes.  Mixtures  of  olive  and  sesame  oils  give 
figures  of  intermediate  character,  the  features  of  the  one  or  the 
other  figure  predominating  according  as  the  first  or  the  second 
oil  forms  the  majority  of  the  mixture ;  and  analogous  differences 
in  the  olive  oil  figure  are  produced  by  admixture  with  other 
oils. 

Baudouin's  test  for  the  presence  of  sesame  oil  is  to  shake  up 

10  c.c.   of  the   sample  for  some  minutes  with  5  c.c.  of  hydro- 
chloric acid,  specific  gravity  1'17,  in  which  0*1  gramme  of  sugar 
has  been  dissolved.      On  separation  of  the  oil  from  the  watery 
liquid,  the  latter  is  found  to  be  tinted  rose  colour,  more  or  less 
marked  according  to  the  proportion  of  sesame  oil  present.     As 
little  as   1   per  cent,  may  be  thus  detected  if  the  agitation  be 
prolonged  for  at  least  ten  minutes  (A.  H.  .Allen).     Or  a  lump  of 
sugar  on  which  fuming  hydrochloric  acid  has  been  dropped  may 
be  shaken  up  with  the  oil.      On  the  other  hand,  according  to 
Villavecchia  and  Fabris,*   olive   oil  of  undoubted  purity  from 
various  localities  in  Italy  gives  the  same  red  coloration  to  the 
aqueous  layer  as  other  oil  to  which  some  5  per  cent,  of  sesame 

011  has  been  added ;  but  if  the  agitation  be  only  kept  up  for  one 
minute,  in  the  case  of  such   pure  olive  oils,  the  watery  layer 
immediately  separates  and  remains   colourless  for  at  least  two 
minutes  ;    whilst    the    milky    oily    layer    remains    greenish    or 
yellowish.     If  only  a  minute  quantity  of  sesame  oil  be  present, 
however,  this  oily  layer  turns  red;    the  coloration  of  the  oil, 
rather  than  of  the  watery  fluid,  is  the  distinctive  part  of  the 
test  (vide  also  p.  153). 

Becchi's  test  (p.  306)  for  cotton  seed  oil  gives  useful  indica- 
tions of  the  presence  of  that  adulterant,  provided  that  the 
refining  of  the  cotton  seed  oil  has  not  been  carried  so  far  as  to 
bring  about  the  entire  withdrawal  of  the  constituent  that  acts 
on  the  silver  nitrate. 

In  many  cases  evidence  of  adulteration  is  obtainable  by  saponi- 
fying the  oil,  separating  the  fatty  acids,  and  determining  their 
fusing  and  solidifying  points  (p.  69)  side  by  side  with  the  corre- 
sponding acids  obtained  from  genuine  oil,  or  mixtures  of  knoivn 
composition,  as  the  precise  numbers  obtained  vary  according  to 
the  particular  mode  of  manipulation  adopted.  Values  varying 
from  22°  to  29°  C.  for  the  fusing  point,  and  from  21°  to  25°  as 
*  Journ.  Soc.  Chem.  Ind.t  1893,  p.  67. 


ADULTERATION    OF    OLIVE    OIL. 


347 


the  solidifying  point,  have  been  recorded  by  different  observers. 
Dieterich  gives  the  following  comparative  values  in  different 
cases,  using  the  same  process  throughout : — 


Melting  Point.      Solidification  Point. 

Olive  oil  (average  of 

19  samples),  . 

26°  to  28°  -5       23°  -5  to  24°  -6 

3 

parts  olive  oil  to  1 

of  arachis  oil, 
cotton  seed  oil, 

29 

30 

26 
27'3 

sunflower  seed  oil, 

25 

20-5 

sesame"  oil, 

28 

25 

linseed  oil,         .                  24  '5 

19-5 

' 

colza  oil,   .                          23  0 

19 

The  figures  thus  deduced,  however,  are  rarely  sufficiently  deci- 
sive of  themselves  to  warrant  any  accurate  deduction  being 
drawn  as  to  the  nature  and  extent  of  the  adulteration. 

Much  the  same  remark  applies  to  tests'  based  on  the  amount 
of  solubility  in  various  menstrua — e.g.,  mixtures  of  alcohol,  water, 
and  glacial  acetic  acid  (Valenta's  test,  p.  55),  although  in  certain 
cases  this  method  gives  useful  corroborative  indications,  especially 
when  carried  out  side  by  side  with  genuine  oil  and  mixtures  of 
known  characters. 

Admixtures  of  hydrocarbons  may  be  detected  by  completely 
saponifying  the  oil  with  alcoholic  soda  or  potash,  evaporating  off 
most  of  the  spirit  and  adding  water,  shaking  up  with  ether, 
separating  the  ethereal  liquid  and  evaporating  off'  the  solvent ; 
with  pure  oil  only  infinitesimal  amounts  of  unsaponified  matter 
(phytosterol,  &c.)  will  be  left,  whereas  hydrocarbon  oils,  if 
present,  will  be  obtained  in  much  larger  quantity  after  evapora- 
tion of  the  ether.  This  test  may  be  made  a  quantitative  one  by 
using  a  weighed  amount  of  oil  and  evaporating  a  known  fraction 
of  the  ethereal  solution  in  a  weighed  vessel  (vide  p.  119). 

Occasionally  metallic  compounds  are  found  in  solution  in  olive 
oil  or  substances  purporting  to  be  such ;  thus  copper  (added  to 
communicate  a  chlorophyll-like  green  shade)  is  occasionally 
present.  Lead  compounds  are  said  to  be  occasionally  added  for 
the  purpose  of  communicating  a  sweeter  taste  to  the  oil.  Metallic 
impurities  of  this  kind  may  be  detected  as  described  on  p.  122. 

Several  special  instruments  have  been  invented  for  the  purpose 
of  examining  olive  oil,  in  order  to  detect  adulterations,  based  on 
different  physical  properties — e.g.,  the  thermal  araeometer  (p.  82); 
the  oleorefractometer  (p.  51);  and  the  diagometer  (p.  53).  The 
polariscope  may  also  be  utilised,  olive  oil  being  slightly  dextro- 
gyrate, and  most  other  oils  Isevogyrate. 

Very  similar  processes  suffice  (mutatis  mutandis)  for  the 
examination  of  other  oils  of  the  olive  class — e.g.,  almond  oil,  oil. 
of  ben  (or  behen),  and  groundnut  (arachis)  oil — and  to  some 
extent  of  oils  of  the  semidrying  class,  such  as  cotton  seed  oil  and 


348  OILS,    FATS,    WAXES,    ETC. 

sesame  oil.  With  the  cheaper  oils  of  this  kind,  hydrocarbons  and 
deodorised  fish  oils  are  the  most  likely  kinds  of  adulterants ; 
the  former  are  detected  and  determined  as  described  on  p.  119; 
the  latter  largely  increase  the  heat  evolution  with  sulphuric  acid, 
and  in  some  instances  give  special  colour  reactions  with  that  acid 
and  other  reagents. 

Rape  Seed,  and  Colza  Oils. — Several  species  of  Brassica 
exist,  and  several  varieties  of  the  rape  plant  have  been  developed 
by  successive  cultivations ;  the  oils  from  these  are  generally 
termed  indiscriminately  "rape"  or  "colza"  oils  in  Britain.  On 
the  Continent,  however,  the  different  kinds  are  still  frequently 
distinguished  by  separate  names.  Thus  Schadler  divides  these 
oils  into  three  classes,  viz.  : — 

Colza  oil  (Colzaol  or  Kohlsaatol)  from  the  original  plaiih,  "  kohlsaat " 

(Brassica  campesfris). 
L'ape    seed   oil   (Rapsol    or    Rapsamenol)   from   a   developed   variety, 

"raps"    (Brassica    campevtris  var.    nap  us,    or    Brassica    no  pus 

oleifera. 
Riibsen  oil  (Rubol  or  Riibsenol)  from  a  different  variety,  "  rubsen  " 

(Brassica  campestris  var.  rapa,  or  Brassica  rapa  oleifera. 

Each  class  is  further  subdivided  according  as  the  plant  is  an 
annual  or  a  biennial,  the  former  yielding  "  summer  oils,"  and  the 
latter  "  winter  oils."  Thus— 

Winter  rape  seed  oil  from  winter  raps  (Brassica  napus  oleifera  biennis). 
Summer         ,,          ,,          summer  raps  ,,  ,,  annua). 

Winter  rubsen  oil  from  winter  riibsen  (B.  rapa  oleijera  biennis}. 
Summer       ,,         ,,        summer  riibsen         ,,          ,,         annua). 

Brassica  nigra  and  Brassica  alba  are  now  more  usually  desig- 
nated Sinapis  nigra  and  Sinapis  alba  respectively  (black  and 
white  mustard),  being  plants  different  in  many  respects  from  the 
cole  or  kohl,  the  seeds  of  which  (kohlsaat)  furnish  the  term 
"  colza  "  by  corruption.  Similarly,  the  allied  Brassica  juncea  is 
now  generally  known  as  Sinapis  juncea,  and  Brassica  cJiinensis 
(Chinese  cabbage)  as  Sinapis  chinensis. 

Cole  or  rape  seed  is  largely  cultivated  in  various  parts  of 
Europe,  especially  France,  Belgium,  Germany,  and  Hungary ; 
also  in  Roumania,  Russia,  India,  and  China.  Much  is  shipped 
from  the  Black  Sea  and  Baltic  ports,  the  expression  being  usually 
carried  out  in  large  mills  after  the  fashion  described  in  Chap,  ix., 
the  seeds  being  crushed  between  rollers,  steamed  to  coagulate 
mucilage  and  increase  fluidity,  and  subjected  by  hydraulic 
pressure  before  cooling. 

The  yield  is  usually  from  30  to  45  per  cent,  according  to  the 
variety  employed.  Schadler  gives  the  following  averages  : — 

Summer  rubsen  and  summer  raps,    .         .         .30  to  35  per  cent. 
Winter  ,,  winter       ,,        .         .         .     35  to  40          ,, 

Winter  colza,    .         .         .         .         .         .         .     35  to  45          ,, 


LINSEED    OIL.  349 

Much  mucilage  accompanies  the  crude  oil ;  this  is  generally 
eliminated  by  the  sulphuric  acid  refining  process  (p.  259),  in 
some  cases  supplemented  by  an  alkaline  treatment  to  get  rid  of 
free  acid,  injurious  for  lubricant  purposes. 

Rape  seed  oil  usually  exhibits  a  total  acid  number  of  175  to 
179,  corresponding  with  the  saponification  equivalent,  320  to  325, 
the  iodine  number  being  98  -5  to  105.*  The  fatty  acids  isolated 
on  saponification  melt  at  18°  to  22°,  whilst  the  specific  gravity  of 
the  oil  at  15°  ordinarily  lies  between  -911  and  -9175.  Accord- 
ingly, the  usual  result  of  adulteration  with  other  fixed  oils  is  a 
rise  in  specific  gravity,  and  a  fall  in  saponification  equivalent. 
Linseed  and  other  drying  oils  raise  the  iodine  number ;  fish  and 
drying  oils  increase  the  heat  evolution  on  mixture  with  sulphuric 
acid.  Thus  Thomson  and  Ballantyne  found  the  "specific  tempera- 
ture reaction"  (water  =  100)  for  rape  oil  to  be  between  125  and 
144,  whereas  that  for  linseed  oil  was  270  to  349,  cod  liver  oil 
giving  243  to  273,  and  menhaden  oil  306  (p.  149).  Pure  rape 
seed  oil  is  practically  immiscible  with  glacial  acetic  acid  at  the 
ordinary  temperature,  and  has  a  lower  efflux  velocity  (higher 
viscosity),  than  most  oils  likely  to  be  used  as  adulterants. 

Hydrocarbon  oils  are  detected  in  the  usual  way  (p.  119). 

Linseed  Oil. — The  oil  expressed  from  the  seeds  of  the  flax 
plant  (Linum  usitatissimum)  is  generally  known  as  linseed  oil ; 
usually  it  is  extracted  on  the  large  scale  in  crushing  mills  by  the 
process  described  in  Chap.  ix.  ;  but  small  quantities  are  prepared 
for  home  consumption  in  different  parts  of  the  world,  more 
especially  Russia,  on  a  much  smaller  scale.  The  seeds  as  found 
in  commerce  are  rarely  all  of  one  kind,  more  or  less  considerable 
admixtures  of  the  seeds  of  other  plants  being  often  present,  the 
result  of  which  occasionally  is  to  seriously  impair  the  quality  of 
the  oil ;  this  sometimes  arises  from  intentional  admixture,  more 
especially  in  the  case  of  hemp  seed,  which  is  stated  to  be  inva- 
riably added  to  the  extent  of  5  per  cent,  and  upwards  to  all 
linseed  shipped  from  the  Black  Sea  ports  ;  but  quite  as  frequently 
it  is  accidental,  on  account  of  other  plants  being  grown  along 
with  flax — e.g.,  mustard  and  rape  ;  this  is  more  especially  the 
case  with  the  red  variety  of  Indian  seed.  The  presence  of 
mustard  seed  in  any  considerable  quantity  is  liable  to  render 
the  oilcake  acrid  and  unsuitable  as  a  cattle  food. 

Linseed  is  chiefly  imported  from  the  Baltic  ports,  Russia 
(Black  Sea),  and  India ;  but  it  is  also  grown  in  considerable 
quantity  in  various  parts  of  Europe,  especially  Poland,  in  Egypt, 
and  the  Brazils.  Seed  grown  in  hotter  climates  is  reputed  to 
yield  oil  comparatively  defective  in  drying  power  and  of  lighter 
colour  than  that  produced  in  colder  regions ;  possibly,  however, 

*  Hence,  some  considerable  amount  of  linolin  or  other  drying  glyceride 
must  be  present,  since  the  iodine  number  of  erucin  is  72 "4,  and  that  of 
rapin  (isomeride  of  ricinolein)  81  •?• 


350  OILS,    FATS,    WAXKS,    ETC. 

this  is  chiefly  due  to«  admixture  of  other  seed  oils  and  not  to 
actual  differences  in  the  oil  contained  in  the  flax  seed.  When 
subjected  to  pressure,  some  20  to  22  per  cent,  of  superior  "  cold 
drawn "  oil  can  be  extracted ;  in  Poland,  Russia,  and  other 
countries  this  is  used  as  an  article  of  food,  being  not  unpleasantly 
tasting.  Later  runnings  prepared  by  hot  pressure  are  darker  in 
colour  and  have  a  disagreeable  acrid  flavour,  rendering  them  only 
suitable  for  technical  purposes.  If  the  seeds  are  expressed  com- 
paratively "green,"  much  more  watery  mucilage  accompanies  the 
oil ;  after  keeping  some  months  they  dry  somewhat  and  a  better 
yield  of  oil  with  a  lessened  admixture  of  vegetable  extractive 
matter  results.  Schadler  describes  the  average  yield  as  being — 

Cold  pressed  oil,     .         .         .         .       20  to  21  per  cent. 
Hot  pressed  oil,      .         .         .  27  to  28         ,, 

Obtained  by  solvents,     .         .         ,       32  to  33        ,, 

The  proportion  of  oil  obtained,  however,  varies  somewhat  wdth 
the  source  of  the  seed  ;  thus  Italian  linseed  yields  somewhat 
more  than  Russian,  and  white  Indian  some  2  per  cent,  more 
than  red  Indian.  Again,  the  yield  varies  according  as  the  seed 
has  been  allowed  to  ripen  fully,  or  as  the  plant  has  been  harvested 
earlier  for  the  flax  crop,  in  which  case  a  smaller  yield  of  oil  is 
usually  obtained. 

In  practice,  pure  linseed  oil  is  never  met  with  commercially, 
and  can  only  be  obtained  by  carefully  handpicking  the  seed 
before  expression.  When  freshly  expressed,  after  refining  by 
sulphuric  acid  (p.  259),  it  has  a  specific  gravity  at  15°  of 
•932  to  '937,  averaging  close  to  '935  (Allen) :  if  any  considerable 
admixture  of  rape  or  other  lighter  oil  is  present,  the  specific 
gravity  falls  to  -930  and  lower.  If,  on  the  other  hand,  the  oil  is 
old  and  has  absorbed  oxygen,  the  specific  gravity  is  more  or  less 
considerably  raised. 

Linseed  oil  contains  some  10  or  15  per  cent,  of  glycerides  of 
solid  fatty  acids  (palmitin,  myristin,  &c.)  The  remaining  liquid 
glycerides  consist  of  those  of  oleic,  linolic,  linolenic,  and  isolino- 
lenic  acids,  in  the  relative  proportions  5,  15,  15,  and  65  per  cent, 
of  the  sum  of  the  four  (Hazura  and  Griissner).  The  total  acid 
number  is  variously  stated  by  different  observers  at  189  to  195-2, 
corresponding  with  a  saponification  equivalent  of  287  to  297, 
representing  a  mean  molecular  weight  of  fatty  acids  of  274  to  285. 
By  directly  titrating  the  acids  prepared  as  carefully  as  possible 
to  avoid  oxidation,  molecular  weights  varying  between  282  and 
295  have  been  observed  in  many  cases ;  but  perceptibly  higher 
values  up  to  307  have  been  noticed  in  some  instances,  leading  to 
the  belief  that  a  higher  homologue  of  linolic  acid,  C00H.1(3O0,  was 
present  (p.  34). 

The  iodine  number  of  linseed  oil  has  been  very  variously  stated 
by  different  observers.  Dieterich  found  different  samples  to  give 


ADULTERATION    OF    LINSEED    OIL.  351 

values  between  161 '9  and  180-9  ;  Benedikt  found  170  to  181  ; 
Holde  179  to  180 ;  Thomson  and  Ballantyne  175-5  to  187*7  accord- 
ing to  the  time  allowed  (vide  p.  180).  Lower  values  down  to  149 
have  been  recorded  by  other  observers  ;  but  in  view  of  the  results 
of  later  researches  on  the  difficulty  of  completely  saturating 
glycerides  with  iodine  unless  a  considerable  time  is  allowed  and 
a  large  excess  of  iodine  employed,  it  would  seem  very  doubtful 
whether  these  lower  values  are  correct  :  probably  180  to  185  is 
nearer  the  true  ultimate  value  for  pure  linseed  oil.* 

The  fatty  acids  separable  from  linseed  oil  have  been  found  by 
various  observers  to  melt  at  temperatures  lying  between  17°  and 
24°,  solidifying  at  13°  to  17°-5  ;  as  linseed  oil  occurs  in  commerce, 
a  small  proportion  of  these  acids  is  usually  present  in  the  free 
state,  free  acid  numbers  being  obtained  varying  from  0*7  to  8-0, 
corresponding  with  amounts  of  free  acid  from  0-4  to  upwards  of 
4  per  cent,  of  the  total  acids  present. 

Linseed  oil  is  especially  characterised  by  the  high  heat  evolu- 
tion brought  about  by  admixture  with  sulphuric  acid  (Maumene's. 
test,  p.  147) ;  in  the  absence  of  fish  oils,  any  considerable  admix- 
ture of  rape  or  other  oil  giving  less  heat  evolution  can  be  readily 
detected  in  this  way.  Livache's  test  (p.  133)  also  affords  an 
indication  as  to  whether  semidrying  oils  or  drying  oils  of  inferior 
quality  have  been  admixed,  inasmuch  as  the  increment  of  weight 
after  a  few  days,  when  no  further  increase  is  noticeable,  is  from 
14  to  15  per  cent,  in  the  case  of  fresh  genuine  linseed  oil,  but 
considerably  less  if  any  large  admixture  of  other  oils  be  present. 
A  simpler  test  based  on  the  shorter  time  required  by  genuine  lin- 
seed oil  to  dry  thoroughly,  as  compared  with  adulterated  samples 
and  other  drying  oils,  is  the  "film  test"  described  on  p.  133 ;  the 
character  of  the  dried  film  formed  is  also  taken  into  account, 
whether  resinoid  and  brittle  when  cold,  or  hard  and  varnish-like 
but  tough,  or  inclined  to  be  readily  broken  up  and  crumbly; 
such  a  practical  test,  although  not  quantitative  in  character,  is 

*  Assuming  linseed  oil  to  contain  only  SO  per  cent,  of  unsaturated 
glycerides  in  the  relative  proportions  given  by  Ha/ura  and  Griissner 
(siipra),  the  calculated  iodine  number  would  be  1S2  05. 

Proportional  Amount  Iodine  Number  of 

Present.  Glyceride. 

Olein,  0-8  x  -05  x  86 -20  =  3  "45 

Linolin,  0'8  x  -15  x  173'57  20'S3 

Linolenin,  O'S  x  -15  x  262*15  -  31  "46 

Isolinolenin,  0'8  x  "63  x  262*15  =  136  "31 


192-05 


whence  it  would  seem  probable  that  the  proportions  of  linolenin  and  iso- 
linolenin  deduced  by  Hazura  and  Griissner  are  a  little  overstated,  at  least 
so  far  as  these  values  are  applicable  to  average  qualities  of  oil. 


352  OILS,    FATS,    WAXES,    ETC. 

often  of  great  value.*  Moreover,  an  old  sample  of  oil  that  has 
already  taken  up  some  amount  of  oxygen,  although  by  no  means 
deteriorated  for  many  ordinary  applications  thereby,  would  be 
indicated  as  of  inferior  quality  by  Livache's  test  if  alone  relied 
on  ;  but  would  not  be  shown  to  be  deficient  in  drying  power  by 
the  "  film  test."  Such  an  oil,  however,  would  possess  a  lower 
iodine  number  than  fresh  oil,  even  if  otherwise  genuine,  inasmuch 
as  the  oxygen  taken  up  appears  to  be  largely  added  on  to  the 
unsaturated  carbon  groups  just  as  iodine  is. 

Fish  oils  (cod,  menhaden,  &c.)  possess  high  thermal  values  by 
Maumene's  test,  and  high  iodine  numbers,  so  that  adulteration 
therewith  is  not  indicated  by  either  reaction.  Boiling  with 
caustic  soda  develops  a  peculiar  reddish  colour  when  these  oils 
are  present ;  chlorine  gas  blown  through  the  oil  causes  a  great 
darkening  in  tint  not  observed  with  pure  linseed  oil.  The 
sulphuric  acid  test  (p.  151)  gives  simply  a  dark  brown  clot  with 
genuine  linseed  oil,  but  a  reddish  brown  spot  if  fish  oils  are 
present. 

Hydrocarbons  are  not  unfrequently  added  as  adulterants  ;  of 
these,  mineral  oils  lower  the  specific  gravity,  and  rosin  oils  raise 
it,  so  that  a  suitable  mixture  of  the  two  has  little  or  no  effect. 
The  test  described  on  p.  119  enables  this  admixture  to  be  readily 
detected  and  the  quantity  determined ;  if  any  considerable 
amount  is  present  the  film  test  indicates  the  fact,  as  the  film 
remains  a  long  time  sticky  with  only  small  quantities,  and  never 
properly  hardens  and  dries  wTith  larger  proportions.! 

Rosin  (colophony)  is  another  adulterant  often  added  along 
with  other  substances  ;  to  detect  and  determine  this  admixture 
the  oil  is  dissolved  in  a  little  pure  alcohol,  and  the  free  fatty 
acids  and  resin  acids  titrated  by  standard  alkali;  water  is  added 
to  the  neutral  mass,  and  the  glyceridic  oils  separated  by  gravi- 
tation or  petroleum  spirit  (p.  118)  ;  the  aqueous  fluid  is  acidu- 
lated, the  mixed  fatty  and  resinous  acids  separated  and  weighed, 
and  the  resin  determined  therein,  as  in  the  case  of  rosin  soaps 
(yellow  soaps,  Chap,  xxi.) 

Hemp  seed  oil  is  a  frequent  constituent  of  linseed  oil,  owing 
to  the  admixture  of  hemp  seed  with  linseed  before  reaching  the 
crushing  mills  ;  to  detect  such  an  admixture  the  oil  is  stirred 
with  concentrated  hydrochloric  acid,  when  a  more  or  less  marked 

*  The  h'lm  test  is  often  modified  by  mixing  the  oil  to  be  tested  with  three 
times  its  weight  of  white  lead,  so  as  to  form  a  paint  which  is  then  applied 
by  a  brush  to  a  clean  surface  ;  a  precisely  similar  trial  is  made  side  by  side 
with  a  standard  sample  of  oil,  and  the  rates  of  drying  compared.  If 
nondrying  oils  be  present,  even  in  only  small  quantity,  the  rate  of  drying 
is  markedly  slackened. 

t  Eosin  oils,  being  strongly  dextrogyrate,  can  be  detected  by  the  polari- 
scope  (p.  50),  pure  linseed  oil  being  faintly  laevorotatory.  Sesame  oil  is 
also  dextrorotatory;  the  sugar  test  (p.  346)  serves  to  detect  it  if  present. 


SPERM    OIL.  353 

green  coloration  is  developed  if  hemp  seed  oil  be  present,  pure 
linseed  oil  giving  a  yellow  colour. 

Sperm  Oil. — Two  varieties  of  sperm  oil  proper  are  obtained 
from  the  Cachelot  whale  (Pliyseter  macroceplialus) ;  one  from  the 
blubber  by  the  ordinary  processes  of  rendering,  the  other  from 
the  "head  matter"  or  contents  of  the  cranial  cavities.  This 
latter  usually  contains  a  larger*  proportion  of  solid  constituents, 
so  that  on  standing  it  soon  becomes  more  or  less  pasty  or  semi- 
solid  from  the  separation  of  spermaceti.  This  solid  constituent 
also  deposits  from  the  blubber  oil  on  standing  and  chilling,  but 
to  a  somewhat  lesser  extent. 

Sperm  oil  thus  freed  from  spermaceti  is  pale  yellow  and  nearly 
odourless  when  prepared  at  comparatively  low  temperatures  from 
fresh  blubber,  £c. ;  although,  like  all  other  fish  and  blubber  oils, 
possessed  of  a  marked  unpleasant  smell  and  darker  colour  when 
extracted  by  greater  heat  from  partly  decomposed  blubber.  Its 
specific  gravity  at  15°  usually  lies  between  -875  and  -884  :  it  has 
but  little  tendency  to  become  rancid,  or  to  "  gum  "  and  thicken 
by  exposure  to  air,  whilst  its  viscosity  is  but  little  affected  by 
change  of  temperature,  so  that  it  forms  a  valuable  lubricating  oil. 
Its  total  acid  number  lies  between  123  and  147,  averaging  near 
132,  corresponding  with  the  saponification  equivalent  426  ;*  its 
iodine  number  is  near  84.  The  fatty  acids  obtained  on  saponi- 
fication melt  at  near  13°,  and  possess  an  iodine  number  near  88, 
and  the  average  molecular  weight  281-294  (Allen — oleic  acid  = 
282,  physetoleic  acid  =  254).  Their  specific  gravity  at  15°  is 
near  -899 ;  nitrous  acid  solidifies  them  readily. 

On  saponification  sperm  oil  yields  60-63  per  cent,  of  insoluble 
fatty  acids,  separated  from  the  monohydric  alcohol  simultaneously 
formed  which  constitutes  39-41-5  per  cent,  (theoretical  values  for 
cetyl  physetoleate,  cetylic  alcohol  =  50-6  per  cent.,  physetoleic 
acid  53-1  per  cent.  ;  for  dodecatyl  physetoleate,  dodecatylic 
alcohol,  44-1  per  cent.,  physetoleic  acid,  60'2  per  cent.) 

Sperm  oil  is  often  adulterated  with  cheaper  vegetable  and 
animal  oils,  the  presence  of  which  is  usually  detected  by  the 
lowering  of  the  percentage  of  alcoholiform  constituents  produced 
on  saponification,  and  by  the  circumstance  that  the  viscosity  of 
genuine  sperm  oil  is  affected  less  by  temperature  variations  than 
that  of  most  other  oils,  so  that  if  other  oils  be  present  the  differ- 
ences between  the  efflux  viscosity  rates  (p.  94)  at  different 
temperatures  (e.g.,  15°C.,  50°C.,  and  100°C.)  will  be  considerably 
increased.  Further,  such  admixture  tends  to  lower  the  saponi- 
fication equivalent.  Hydrocarbon  oils  increase  the  saponification 
equivalent  and  the  amount  of  ether  residue  obtained  by  the  process 
described  on  p.  119  ;  but  this  residue,  consisting  largely  of  fluid 
hydrocarbons,  is  readily  distinguishable  from  the  alcoholiform 
residue  obtained  with  pure  sperm  oil,  more  particularly  by  the 
*  Cetyl  physetoleate  =  478.  Dodecatyl  physetoleate  =  422. 

23 


354  OILS,    FATS,    WAXES,    ETC. 

acetyl  test  (p.  186).  Vegetable  and  animal  glyceridic  oils  lead 
to  the  presence  of  more  or  less  considerable  amounts  of  glycerol 
in  the  products  of  saponification ;  genuine  sperm  oil  gives  but 
little.  Fish  and  sharkliver  oils  give  special  colorations  with 
sulphuric  acid  on  account  of  the  biliary  constituents  present. 

Tallow. — The  terms  "  tallow "  and  "  suet,"  especially  the 
former,  are  often  used  indiscriminately  to  denote  both  the  solid 
adipose  tissues  of  various  quadrupeds  (more  particularly  the  ox 
and  sheep),  and  the  fatty  matters  thence  rendered  by  suitable 
treatment  so  as  to  separate  them  from  the  nitrogenous  cellular 
tissue ;  preferably,  however,  the  term  "  suet "  should  only  be  ap- 
plied to  the  untreated  animal  fatty  tissues,  whilst  the  word  "tallow" 
should  only  imply  the  fatty  matters  thence  extracted  and  freed 
from  cell  walls,  &c.  In  this  sense  "  tallow  "  includes  the  rendered 
fats  obtained  from  the  ox,  sheep,  goat,  stag,  and  other  quadrupeds, 
excluding  the  horse  and  hog,  the  fats  from  which  are  generally 
known  as  " horsegrease "  (maresgrease)  and  "lard"  respectively. 
According  to  the  breed,  age,  and  sex  of  the  cattle  or  sheep 
from  which  the  tallow  is  obtained,  the  hardness  of  the  substance 
varies  ;  the  mode  of  feeding  and  climate  also  produce  variations  ; 
whilst,  as  in  the  case  of  hog's  lard,  the  consistency  of  the  product 
differs  considerably  with  the  part  of  the  carcase  furnishing  the 
fatty  tissue.  These  variations,  however,  so  far  as  is  known,  do 
not  affect  the  general  character  of  the  fat  as  regards  its  consti- 
tution; whether  harder  or  softer  it  essentially  consists  of  the 
glycerides  of  oleic,  stearic,  and  palmitic  acids,  the  former  being 
present  in  the  larger  proportion  the  softer  the  fat.  In  general, 
veal  tallow  (from  calves)  is  softer  than  that  similarly  obtained 
from  oxen ;  whilst  cow  tallow  and  bull  tallow  are  harder  still : 
these  are  all  generally  included  in  the  term  "  beef  tallow." 
"  Mutton  tallow  "  from  sheep  (ewes  and  rams)  is  usually  harder 
than  beef  tallow,  but  not  invariably :  "  goat's  tallow "  (often 
included  in  mutton  tallow)  much  resembles  that  substance.  In 
the  trade  a  variety  of  grades  exist,  in  many  cases  known  by 
special  names  either  denoting  the  country  from  which  the 
material  is  shipped  ("River  Plate  tallow,"  "  Australian  tallow," 
"  Eussian  tallow,"  &c.)  or  given  for  some  other  reason — e.g., 
P.  Y.  C.  tallow  =  Petersburg  yellow  candle  (or  prime  yellow 
candle),  a  particular  quality  irrespective  of  source ;  "  Prime 
Butchers'  Association  tallow,"  or  "  North  American,"  mostly 
shipped  from  New  York  ;  "  Western,"  imported  from  New 
Orleans:  "tripe  tallow"  and  "town  tallow,"  grades  usually 
softer  and  somewhat  inferior  because  of  admixture  with  waste 
dripping,  kitchen  grease,  and  other  similar  materials.  In  many 
cases  large  admixtures  of  other  foreign  substances  are  added — 
e.g.,  cotton  seed  stearine  ;*  woolgrease  and  Yorkshire  grease,  and 

*  According  to  R.  Williams  cotton  seed  oil  is  often  used  as  an  adulterant 
in  the  case  of  softer  tallows  (vide  Journ.  Soc.  Chem.  Ind.,  1888,  p.  186). 


TALLOW.  355 

the  stearines  thence  obtained  by  distillation  and  pressure ;  bone 
grease  ;  together  with  solid  non-fatty  matters  such  as  China  clay, 
whiting,  starch,  &c.,  the  presence  of  which  is  easily  recognised 
by  applying  a  solvent  and  filtering  (p.  123). 

The  specific  gravity  at  15°  of  tallow  lies  between  0-925  and 
0-940,  values  between  0-925  and  0-929  being  obtained  with  beef 
tallow,  and  somewhat  higher  ones,  between  0-937  and  0-940,  with 
mutton  tallow  (Hager).  Dieterich  found  slightly  higher  values 
up  to  0-952.  The  melting  point  and  solidifying  point  vary 
considerably,  41°  to  51°  being  recorded  by  different  observers  for 
the  former,  and  a  few  degrees  lower  for  the  latter.  The  fatty 
acids  obtained  on  saponification  also  vary  similarly  with  the 
hardness — i.e.,  the  proportion  of  olein,  the  melting  point  being 
usually  near  47°  with  tallow  of  good  quality.  The  solidifying 
point  as  determined  by  Dalican's  process  (p.  74),  sometimes 
termed  the  "  titre  "  of  the  tallow,  affords  the  best  criterion  of 
quality,  so  far  as  such  physical  tests  go:  44°  represents  a  mixture 
of  equal  quantities  of  stearic  and  oleic  acids,  lower  values  being- 
obtained  when  oleic  acid  preponderates,  and  higher  ones  when 
stearic  acid  is  in  excess.  On  the  Continent,  it  is  often  stipulated 
that  the  solidification  point  shall  not  fall  below  44°  when  the 
tallow  is  intended  for  candlemaking ;  whereby  not  only  are  the 
softer  genuine  (or  comparatively  so)  tallows  excluded,  but  also 
those  largely  adulterated  with  such  substances  as  cotton  seed 
oil,  cotton  seed  stearine,  Yorkshire  grease,  stearine  from  dis- 
tilled grease,  £c.,  as  the  presence  of  these  materials  tends  to 
lower  the  melting  point  of  the  mixed  fatty  acids  obtained. 
Woolgrease  and  Yorkshire  grease  products  are  especially  ob- 
jectionable in  this  connection,  because  they  contain  more  or  less 
considerable  quantities  of  cholesterol  hydrocarbons  and  other 
unsaponifiable  substances,  which  not  only  directly  diminish  the 
amount  of  stearic  acid  present,  but  also  further  diminish  the 
quantity  of  solid  fatty  acids  obtainable  by  pressing,  as  they 
interfere  with  the  proper  "seeding"  or  crystallisation  of  the 
press  cake  (vide  p.  367).  The  determination  of  these  unsaponi- 
fiable matters  in  tallow  adulterated  therewith,  is  carried  out  as 
described  on  p.  119. 

Fresh  tallow  contains  very  little  free  fatty  acid ;  but  tallow 
that  has  become  more  or  less  rancid  often  contains  considerable 
amounts,  up  to  12  per  cent,  (calculated  as  oleic  acid);  25  per 
cent,  was  found  by  Deering  in  a  sample  six  years  old.  When 
tallow  is  not  particularly  rancid,  and  yet  contains  a  considerable 
amount  of  free  acid,  it  is  very  probable  that  it  has  been 
adulterated  with  distilled  "  stearine  "  (largely  consisting  of  free 
fatty  acids).  The  total  acid  number  usually  lies  between  193 
and  198,  representing  the  saponification  equivalent  283  to  293, 
averaging  near  288,  and  corresponding  with  a  mean  molecular 
weight  of  fatty  acids  of  near  276  (palmitic  acid  =  256,  oleic 


356  OILS,    FATS,    WAXES,    ETC. 

acid  =  282,  stearic  acid  —  284).  The  iodine  number  has  been 
found  by  different  observers  to  lie  between  35  and  45,  with  an 
average  of  about  40 ;  since  pure  olein  has  the  iodine  number 
86 "2,  this  indicates  an  average  amount  of  olein.  of  somewhat  less 
than  50  per  cent,  (about  46),  and  a  proportion  of  solid  glycerides 
of  somewhat  above  50  per  cent,  (about  54).  According  to  the 
author's  experience,  in  the  absence  of  adulterations  the  deter- 
mination of  the  iodine  value  can  be  made  into  a  useful  test  of 
quality  for  candlemaking  purposes,  the  proportion  of  solid  fatty 
acids  obtainable  being  greater  the  less  the  iodine  absorption ; 
but  when  pressed  coker  butter  or  palm  kernel  oil  has  been 
added,  the  iodine  number  is  reduced  without  a  corresponding 
increase  in  amount  of  solid  fatty  acids  of  high  melting  point 
obtainable ;  and  the  same  remark  applies  to  wToolgrease,  wool 
stearine,  and  similar  substances.  When  circumstances  permit,  the 
best  indications  as  to  adulterations  of  this  kind  are  obtained  by 
saponifying,  separating  the  fatty  acids,  allowing  them  to  crystal- 
lise, and  expressing  them  in  a  small  experimental  laboratory 
press,  determining  the  quantity  and  melting  point  of  the  press 
cake,  and  subjecting  the  expressed  oleic  acid  to  examination  as 
regards  its  iodine  absorption,  elaidin  reaction,  colour  reactions 
with  sulphuric  and  nitric  acids,  tfec.,  heat  evolution  with  sulphuric 
acid  (Maumene's  test.  p.  147),  amount  of  unsaponifiable  matters 
present,  and  so  on ;  samples  of  genuine  tallow  of  different 
qualities  being  examined  side  by  side  in  the  same  way. 

Muter  and  Koningh*  recommend  a  process  based  on  somewhat 
similar  principles,  where  the  solid  and  liquid  fatty  acids  are 
separated  by  conversion  into  lead  salts  and  solution  of  lead  oleate, 
&c.,  by  ether,  wherein  lead  stearate  and  palmitate  are  but 
sparingly  soluble.  By  carrying  out  the  saponification  and  subse- 
quent processes  in  a  uniform  prescribed  way,  the  quantity  and 
characters  of  the  liquid  fatty  acids  ultimately  separated  from  the 
soluble  lead  salt,  afford  useful  indications  respecting  adultera- 
tion. Thus,  they  found  that  the  iodine  number  of  the  liquid 
acid  obtainable  from  pure  tallow,  is  uniformly  close  to  90, 
substantially  identical  with  that  theoretically  requisite  for  pure 
oleic  acid.  Lard,  on  the  other  hand,  gives  a  liquid  acid  possessing 
a  distinctly  higher  iodine  number,  close  to  93;  whilst  the  liquid 
acids  from  cotton  seed  oil  give  a  considerably  higher  iodine 
value,  near  to  135. 

Tallow  that  has  become  rancid  by  keeping  generally  whitens 
during  the  process  ;  owing  to  the  large  amount  of  decomposition 
with  formation  of  free  fatty  acids  that  occurs  (supra),  such  tallow 
is  unsuitable  for  lubricating  purposes ;  the  byeproducts  of  the 
decomposition,  moreover,  cause  soap  made  from  such  tallow  to 
"  work  foxy,"  or  become  discoloured  of  a  brownish  red,  so  that 
for  milled  or  other  toilet  soaps  intended  to  be  white  or  tinted 
*  Analyst,  1889,  p.  61 ;  1890. 


BEESWAX.  357 

delicate  shades,  such  tallow  should  be  avoided  in  the  manufacture 
of  the  "  stock  soap  "  used. 

Beeswax. — A  good  deal  of  dispute  has  taken  place  at  various 
times  as  to  whether  the  wax  of  the  bee,  wasp,  and  similar  insects 
is  a  distinct  product  of  secretion  due  to  their  own  special  life 
action,  or  is  simply  precontained  in  the  pollen  and  nectar  of 
flowers,  &c.,  serving  as  their  food,  and  isolated  therefrom  by 
digesting  away  or  otherwise  removing  the  other  constituents. 
This  latter  view  appears  probable,  inasmuch  as  when  bees  are 
fed  upon  sugar  only,  they  appear  to  be  incapable  of  developing 
wax  to  any  notable  extent.  On  the  other  hand,  although  the 
character  of  bee  food  necessarily  varies  much  in  different  parts 
of  the  world,  yet  the  chemical  constitution  of  beeswax  does  not 
differ  anything  like  so  widely.  Samples  of  beeswax  from  numerous 
localities  in  Europe,  Asia,  South  America,  and  Australia,  all  pos- 
sessed very  similar  compositions  (Hehner*) — viz.,  they  essentially 
consisted  of  a  mixture  of  about  1  part  of  free  cerotic  acid  to  6  of 
myricin  (vide  infra) ;  a  result  hardly  compatible  with  the  notion 
that  the  wax  pre-existed  as  such  in  the  pollen  and  nectar  of  the 
very  wide  variety  of  flowers,  &c.,  furnishing  food  to  the  bees 
in  these  different  quarters  of  the  globe.  Andaquia  wax  (wax 
of  Apis  fasciata,  largely  used  for  candlemaking  in  South 
America)  appears  to  be  substantially  identical  with  the  ordinary 
beeswax  of  Apis  mellifera ;  and  the  same  remark  applies  to 
Antilles  wax  (Apis  fasciata  ?),  and  to  Madagascar  wax  (Apis  uni- 
color),  although  frequently  beeswax  of  tropical  and  subtropical 
origin  is  darker  coloured  and  less  readily  bleached  than  that 
produced  in  more  temperate  climates. f  The  wax  of  the  Eastern 
Archipelago,  again,  differs  but  little  from  that  obtained  from 
other  sources,  although  mainly  produced  by  a  different  species 
(Apis  dorsata). 

In  order  to  obtain  beeswax  the  ^ombs  are  simply  drained  of 
honey  and  then  melted  in  hot  water  and  stirred  about ;  the  wax 
collects  on  the  top  as  an  oily  layer,  which  is  removed  after  cooling 
and  hardening ;  after  remelting  by  heat  alone  (without  water) 
and  casting  into  blocks,  the  "virgin"  wax  is  ready  for  the 
market.  A  large  proportion  is  used  for  numerous  purposes 
without  further  preparation ;  for  certain  purposes  bleaching  is 
requisite,  effected  either  by  means  of  exposure  to  air  and  sunlight 
in  thin  shavings  (p.  268),  or  by  means  of  chemicals,  preferably 
dilute  sulphuric  acid  and  potassium  dichromate  (p.  266). 

Beeswax  is  readily  soluble  in  carbon  disulphide  and  fusel  oil ; 
it  dissolves  in  about  10  parts  of  boiling  ether,  less  completely  in 
cold  ether,  benzene,  or  petroleum ;  in  cold  alcohol  it  is  nearly 

*  Vide  Analyst,  1883,  vol.  viii.,  p.  16. 

t  Wax  from  the  vicinity  of  Bordeaux  appears  to  be  the  variety  most 
difficult  to  bleach;  whether  from  some  local  peculiarity  in 'the  flowers 
frequented  by  the  bees;  or  for  some  other  reason,  is  unknown. 


358  OILS,    FATS,    WAXES,    ETC. 

insoluble,  but  dissolves  in  about  300  parts  of  boiling  spirit.  In 
the  case  of  most  solvents,  some  parts  of  the  wax  dissolve  much 
more  freely  than  other  portions ;  thus  in  the  case  of  hot  alcohol 
a  small  quantity  of  "  cerolein  "  is  left  undissolved,  consisting  of 
fatty  matter,  principally  palmitin  and  olein ;  the  proportion  of 
this  constituent  varies  in  waxes  of  different  origin,  but  is  never 
large,  so  that  the  presence  of  fatty  glycerides  in  any  quantity  is 
only  due  to  adulteration.  Natural  wax  contains  a  considerable 
amount  of  free  acid  (from  12  to  16  per  cent.,  calculated  as  cerotic 
acid — Hehner) ;  that  bleached  by  means  of  dichromate  usually 
contains  somewhat  more  (17  to  18  per  cent.)  ;  but  airbleaching 
appears  to  produce  no  measurable  increase  in  the  free  acidity. 
The  free  acid  in  raw  wax  appears  to  be  chiefly  cerotic  acid, 
C2-H54O2,  together  with  a  little  melissic  acid,  C30H"6002,  ;  by 
treating  the  wax  with  limited  quantities  of  hot  alcohol  these  are 
dissolved  out,  myricin  (the  palmitic  ether  of  myricylic  alcohol, 
iC30H61 .  O .  C16H0jlO)  constituting  the  great  majority  of  the  un- 
dissolved part. 

Beeswax  has  at  15°  C.  the  specific  gravity  nearly  -96  (numbers 
varying  between  '956  and  '975  being  recorded  by  different 
observers).  At  98°  to  99°  the  specific  gravity  is  '818  to  '827 
(Allen).  Airbleaching  seems  to  produce  little  or  no  alteration 
in  the  density,  but  chemically  bleached  wax  is  usually  rendered 
a  little  more  dense  by  the  process.  The  melting  point  is  always 
close  to  63°,  values  varying  between  61°  and  65°  being  recorded 
by  numerous  observers  ;  the  melted  substance  re-solidifies  at  one 
or  two  degrees  lower  than  the  temperature  of  complete  fusion. 
The  free  acid  number  has  been  found  by  Hehner,  Hiibl,  Buisine, 
and  other  observers  to  be  subject  to  comparatively  little  varia- 
tion, almost  invariably  lying  between  17  and  21  in  the  case  of 
unbleached  wax,  corresponding  with  12*5  to  15*5  per  cent,  of 
cerotic  acid) ;  whilst  the  ester  number  (p.  162)  lies  between  72 
and  76  (corresponding  with  87  to  92  per  cent,  of  myricin) ;  the 
sum  of  the  cerotic  acid  arid  myricin  thus  calculated  is  generally 
a  little  above  100,  showing  that  some  amount  of  other  consti- 
tuents of  lower  molecular  weight  is  also  present.  In  confirma- 
tion of  this  the  iodine  number  has  been  found  to  be  appreciable, 
though  low,  averaging  about  10  (8*3  to  ll'O,  Buisine),  indicating 
the  presence  of  a  perceptible  amount  of  unsaturated  compounds 
(possibly  hydrocarbons).  On  saponification  with  continued  boil- 
ing (for  at  least  an  hour)  with  excess  of  alcoholic  potash,  genuine 
beeswax  furnishes  53  to  54  per  cent,  of  crude  myricylic  alcohol 
(Benedikt),  corresponding  with  81 '8  to  83'4  of  myricin  (myricylic 
palmitate).* 

*  Wax  bleached  by  the  air  process  is  often  admixed  with  a  few  per  cents, 
of  fatty  matter  which  seems  to  facilitate  the  bleaching  action  in  some  way 
not  thoroughly  understood.  A  small  quantity  of  oil  of  turpentine  is  some- 
times added  for  the  same  reason  ;  in  this  case  the  bleaching  is  probably 


SPERMACETI.  359 

Beeswax  is  often  largely  adulterated,  more  especially  with 
paraffin  wax  and  allied  hydrocarbons  (cerasin  and  similar  high- 
melting  mineral  waxes) ;  stearic  acid ;  colophony,  burgundy 
pitch,  and  other  similar  resinous  matters  ;  and  solid  weighting 
materials,  such  as  china  clay,  barium  sulphate,  yellow  ochre, 
starch,  and  sulphur.  Vegetable  waxes  (carnauba  wax,  &c.)  are 
often  added ;  and  in  some  cases  several  per  cents,  of  water  are 
artfully  worked  into  the  mass.  This  last  admixture  is  readily 
detected  by  the  methods  described  in  Chap,  vi.,  p.  122.  Mineral 
adulterations  are  readily  detected  by  incinerating  the  wax  and 
burning  off  carbonaceous  matters  so  as  to  obtain  the  clay,  &c.,  as 
residue.  By  dissolving  in  ether,  warm  oil  of  turpentine,  chloro- 
form, benzene,  or  other  suitable  solvent,  these  substances,  as 
well  as  starchy  matters,  and  other  analogous  adulterants,  are  left 
undissolved,  and  may  be  obtained  by  filtration  and  washing.* 
Stearic  acid,  if  added  in  any  quantity,  is  detected  by  the  increased 
free  acid  number,  and  by  the  melting  point  and  general  characters 
of  the  acids  ultimately  obtained  from  the  soap  formed  on  shaking 
the  wax  with  hot  alcohol,  and  titrating  with  standard  alkali  and 
phenolphthalein  (p.  118).  Glycerides,  similarly,  may  be  detected 
and,  to  some  extent,  estimated  by  the  formation  of  glycerol  on 
saponification ;  whilst  adulteration  with  carnauba  wax  may  be 
detected  by  the  examination  of  the  fatty  acids  formed  by  saponi- 
fying the  impure  myricin  left  insoluble  on  agitation  with  alcohol 
and  alkali,  palmitic  acid  (m.p.  62°,  and  equivalent  256)  being 
the  chief  constituent  formed  from  genuine  wax,  whilst  carnauba 
wax  mostly  produces  cerotic  acid  (m.p.  79°,  and  equivalent  410). 
The  presence  of  hydrocarbons  is  indicated  by  the  decreased  ester 
number  ;  or  the  wax  may  be  carbonised  by  heating  5  grammes 
with  50  c.c.  of  concentrated  sulphuric  acid  to  130°  0.  in  a 
capacious  flask  for  ten  minutes ;  much  sulphurous  acid,  &c.,  is 
evolved,  and  the  mass  chars,  finally  becoming  nearly  solid ;  the 
acid  is  washed  out  with  water,  adherent  water  removed  by 
alcohol,  and  the  residue  treated  with  ether,  preferably  in  a  Soxhlet 
tube  (p.  238),  whereby  the  hydrocarbon  is  dissolved  out,  along 
with  a  little  wax  that  has  escaped  the  action  of  the  acid.  By 
repeating  the  acid  treatment  this  is  removed,  and  the  cerasin,  &c., 
finally  obtained  in  a  weighable  fcjrm.f 

Spermaceti. — The  true  origin  of  spermaceti  (formerly  regarded 
as  whale-spawn,  Sperma  ceti)  appears  to  have  been  unknown, 

quickened  by  the  formation  of  peroxide  of  hydrogen  during  the  oxidation 
of  the  turpentine  by  the  oxygen  of  the  air  in  contact  with  water  (ride  p.  269). 

*  Traces  of  flour  are  often  normally  present  in  pressed  or  rolled  wax 
owing  to  the  use  of  flour  for  dusting  over  the  rollers  or  press  to  prevent  the 
wax  from  sticking  (Allen). 

t  Respecting  the  detection  of  adulterations  of  beeswax,  vide  Journ.  Soc. 
Ohem.  Ind.,  1890,  p.  771  ;  1891,  pp.  728,  729,  860,  1014.  For  the 
bibliography  of  beeswax  and  the  waxes  used  for  its  adulteration,  vide  ibid., 
1892,  pp.  756,  757. 


360  OILS,    FATS,    WAXES,    ETC. 

long  after  it  had  come  into  some  amount  of  use  for  the  prepara- 
tion of  unguents  ;  its  employment  for  candlemaking,  like  that  of 
whale  oils  for  burning  in  lamps,  seems  practically  to  date  from 
somewhat  upwards  of  a  century  ago  when  the  whale  fishery 
began  to  be  extensively  pursued  for  commercial  purposes.  Even 
at  the  present  day,  however,  considerable  misapprehension 
appears  to  exist  both  as  to  the  species  of  cetacea  yielding  it 
and  the  part  of  the  body  from  which  it  is  derived.  Whilst  the 
best  known  source  is  the  "head  matter"  of  the  Pltyseter  macro- 
cephalus  (p.  300),  which  largely  consists  of  solid  crystallised 
spermaceti  when  taken  from  the  dead  carcase,  it  is  also  the  fact 
that  considerable  quantities  are  obtainable  from  the  blubber  oil 
of  the  same  cetacean ;  during  winter  this  oil  sets  so  far  solid  by 
deposition  of  spermaceti  that  it  requires  to  be  steamed  to  enable 
it  to  be  removed  from  the  casks.  Moreover,  analogous  if  not 
identical  solid  deposits  form  on  similarly  chilling  for  lengthened 
periods  the  blubber  oils  of  various  other  species  (vide  p.  301). 

The  semisolid  oils  containing  scales  of  spermaceti  will  not  bear 
any  great  degree  of  pressure  during  filtration  to  separate  the 
solid  matter,  as  this  very  readily  passes  through  even  the  most 
impervious  filter  cloths  :  accordingly  the  first  operation  consists 
of  "  bagging  " — i.e.,  the  material  is  placed  inside  long  bags  of  hair 
or  canvas  where  gravitation  only  effects  a  separation  between 
the  solid  and  liquid  constituents.  The  "bagged  sperm"  is  then 
transferred  to  square  bags,  forming  a  soft  flaky  mass  :  a  pile  of 
bags  and  boards  is  formed  in  successive  alternate  layers,  and  by 
placing  weights  on  the  top  of  the  pile,  at  first  small  but  subse- 
quently greater,  most  of  the  remaining  fluid  oil  is  gradually 
squeezed  out  until  the  mass  is  sufficiently  firm  to  bear  hydraulic 
cold  pressure  carried  out  in  presses  closely  akin  to  those  used 
for  stearine  After  cold  pressing,  the  sperm  cake  is  remelted, 
granulated,  and  pressed  several  times  over  at  gradually  increasing 
pressures  and  temperatures  so  as  to  remove  the  last  portions  of 
fluid  oil,  a  refining  treatment  with  potash  (p.  261)  being  inter- 
polated between  the  last  pressings  so  as  to  remove  not  only  the 
last  traces  of  colouring  matter,  but  also  free  fatty  acids  formed 
by  hydrolysis.  Finally,  a  glistening  white  mass  is  obtained, 
mainly  consisting  of  cetylic  palmitate  (016H31  .  O  .  C16H33O), 
melting  at  near  45°  C.,*  and  of  specific  gravity  near  '810  at  99°. 

The  pressings  from  these  various  operations  are  methodically 
worked  up,  in  such  fashion  as  ultimately  to  obtain  a  second 
quality  of  spermaceti  of  somewhat  lower  melting  point :  the 
potash  foots  obtained  during  refining  yield  on  acidulation  with  a 
mineral  acid  a  mixture  of  impure  spermaceti  and  palmitic  acid  ; 

*  According  to  L.  Field  (Journ.  Soc.  Arts,  vol.  xxxi.,  p.  840),  the 
spermaceti  extracted  from  the  blubber  oils  of  the  true  bottlenose  whale 
(Balcena  rosirata)  has  a  slightly  higher  melting  point  than  that  from  the 
sperm  whale  or  cachelot  (Physeter  macrocephalus). 


SPERMACETI.  3G1 

when  this  is  worked  up  with  the  other  runnings  a  considerable 
amount  of  free  fatty  acids  is  contained  in  the  ultimate  product. 
30  per  cent,  and  upwards  of  such  free  acids  (essentially  palmitic 
acid)  are  sometimes  present  in  spermaceti  of  this  lower  grade. 

Spermaceti  is  sometimes  adulterated  with  free  stearic  and 
palmitic  acids  (not  derived  from  the  foots,  as  above  described), 
hard  pressed  glycerides  (pressed  tallow),  and  animal  waxes  and 
paraffin  wax.  These  latter  additions  raise  the  saponification 
equivalent,  whilst  free  fatty  acids  and  glycerides  lower  it.  The 
detection  of  these  adulterants  is  effected  in  ways  substantially 
the  same  as  those  above  mentioned  with  respect  to  beeswax. 


362  OILS,   FATS,    WAXES,    ETC. 


§  6.  The  Candle  Industry. 


CHAPTER  XVI. 
MATERIALS    USED    IN    CANDLEMAKING. 

ORIGIN  OF  CANDLES. 

IN  all  probability  the  earliest  forms  of  illuminating  agents  of  the 
nature  of  candles  (i.e.,  containing  something  serving  the  purpose 
of  wick  surrounded  by  more  or  less  solid  combustible  matter 
adherent  thereto)  were  simple  links  or  flambeaux  consisting  of 
fibrous  vegetable  stalks,  &c.,  soaked  in  natural  bitumen  or 
asphalt,  vegetable  resin,  or  animal  fatty  matter ;  these  being- 
obvious  developments  of  the  yet  simpler  primeval  torches  con- 
sisting of  splinters  of  pine  and  similar  woods,  either  naturally 
full  of  resinous  matter,  or  externally  smeared  therewith. 

Lamps,  or  reservoirs  of  fluid  oil  furnished  writh  a  wick  for 
burning,  seem  to  have  been  invented  at  a  very  early  period  of 
the  world's  history,  and  to  have  speedily  superseded  the  primeval 
resinous  wooden  torch  for  general  household  purposes  amongst 
the  earlier  civilised  nations,  although  for  outdoor  illuminations, 
and  especially  amongst  the  Scandinavians  and  other  northern 
tribes,  pine  splinter  torches  and  similar  rude  contrivances  of  the 
flambeau  character  were  still  chiefly  used. 

Rushlights,  where  the  pith  of  rushes  served  as  wick  and  where 
the  combustible  matter  was  tallow  or  other  animal  fat  applied 
by  dipping  the  pith  in  melted  grease,  and  superior  forms  where 
wax  was  used  instead  of  tallow,  moulded  by  hand  round  the  rush 
whilst  rendered  plastic  by  means  of  warmth, *  appear  to  have 
been  in  considerable  use  amongst  the  Romans,  hempen  or  flaxen 
unspun  wicks  taking  the  place  of  rush  pith  in  the  better  kinds  of 
wax  lights ;  thus  in  Herculaneum  the  remains  of  a  chandler's 
•establishment  have  been  unearthed,  whilst  numerous  passages  in 
various  Latin  authors  indicate  that  the  torch  (tceda),  the  lamp 
{lucerna),  the  tallow  candle  or  rushlight  (sebaceus),  and  the  wax 

*  Such  a  candle,  believed  to  date  from  the  1st  century,  is  in  the  British 
Museum. 


CANDLE    MATERIALS.  363 

light  (cereus)  were  all  in  use  in  the  early  centuries  of  the  Christian 
era;*  the  oil  lamp  being  still  the  most  extensively  used  illuminant 
amongst  the  well  to  do  classes,  wax  lights  ranking  next. 

With  the  exception  that  wax  tapers  were  largely  used  for 
ecclesiastical  purposes,  as  well  as  private  illumination,  during 
the  middle  ages,  and  that  some  improvements  were  consequently 
introduced  as  regards  their  general  size  and  finish,  little  advance 
in  the  art  of  candlemaking  seems  to  have  been  brought  about 
until  the  fifteenth  century,  when  the  process  of  "moulding"  was 
introduced  by  the  Sieur  de  Brez  ;  but  the  manufacture  of  rush- 
lights and  of  "  dip  "  tallow  candles,  as  well  as  of  waxen  tapers, 
had  by  that  time  become  a  trade  of  itself,  having  to  a  consider- 
able extent  passed  out  of  the  region  of  ordinary  household 
operations  carried  on  by  each  family  for  the  supply  of  its  own 
wants,  and  into  the  hands  of  special  candlemakers  (candelarii,  or 
chandlers),  who  made  tallow  and  other  candles  for  sale  to  the 
general  public,  at  any  rate  in  the  larger  towns.  In  country 
districts,  however,  rushlights  and  tallow  candles,  of  more  or  less 
rough  home-made  manufacture,  still  continued  to  be  the  only 
available  means  of  artificial  illumination  other  than  oil  lamps, 
for  the  great  majority  of  the  population;  a  state  of  matters, 
indeed,  not  entirely  obsolete  even  at  the  present  day  in  some 
highly  rural  localities.  In  some  savage  countries  highly  olei- 
ferous  nuts,  strung  together  on  a  fibrous  twig,  are  burnt  like 
candles  ;  as  one  is  consumed  the  next  one  becomes  lighted  and 
burns  till  exhausted. 

Combustible  Materials. — At  the  present  time  the  com- 
bustible matters  (in  addition  to  the  wicks)  used  for  candle- 
making  may  be  divided  into  four  classes — viz.,  (1)  those  natural 
glycerides  which  are  sufficiently  solid  at  ordinary  temperatures 
to  admit  of  being  used  for  the  purpose,  or  which  yield  sufficiently 
solid  glycerides  by  pressure;  more  especially  tallow  and  similar 
animal  fats,  together  with  vegetable  products  of  corresponding 
consistency,  such  as  coker  stearine,  piney  tallow,  and  the  solid 
fats  of  the  Stillingia,  Bassia,  and  other  genera.  (2)  Substances  of 
waxy  character,  such  as  beeswax  and  the  vegetable  waxes,  essen- 
tially consisting  of  nonglyceridic  compound  ethers  ;  also  including 
spermaceti.  (3)  Free  fatty  acids  of  sufficiently  high  melting  point, 
obtained  from  natural  oils  and  fats  by  saponification  processes, 
and  mechanical  separation  of  more  fluid  ingredients.  (4)  Paraffin 
wax  and  analogous  hydrocarbons  of  mineral  origin,  or  formed  by 
destructive  distillation.  Of  these  the  substances  of  the  latter 
two  classes  are  those  most  largely  used,  more  especially  the  last, 
in  this  country,  although  "stearine"  candles  are  somewhat  pre- 
ferred on  the  Continent.  The  trade  in  wax  and  spermaceti 
candles  is  comparatively  small,  although  by  no  means  insigni- 

*  Vide  Leopold  Field,  "Cantor  Lectures, "  Journ.  Soc.  Arts,  vol.  xxxii., 
p.  821,  et  seq. 


364:  OILS,    FATS,    WAXES,    ETC. 

ficant  in  actual  amount ;  whilst  the  use  of  unsaponified  glycerides, 
whether  as  tallow  "  dip "  candles,  consisting  of  such  glycerides 
only,  or  as  "  composite ''  mixtures  of  glycerides  and  free  fatty 
acids,  is  steadily  diminishing  in  favour  of  the  other  kinds  of 
illuminants,  although  far  from  being  extinct,  especially  in  the 
case  of  iiightlights,  which  are  largely  made  of  coker  stearine. 

In  the  manufacture  of  tallow  dip  candles  no  special  preparation 
of  the  tallow  for  use  is  requisite  further  than  the  rendering  and 
purifying  processes  already  described  (Chaps,  x.  and  xi.)  ;  the 
harder  varieties  are  usually  preferred,  although  if  too  hard  there 
is  more  risk  of  cracking.  In  the  case  of  beeswax,  air  and  light- 
bleached  wax  (p.  268)  is  employed  in  preference  to  that  bleached 
by  chemical  processes,  especially  such  as  involve  the  use  of  chlor- 
ine ;  for,  irrespective  of  a  greater  tendency  to  become  yellowish 
on  keeping,  such  chemically  bleached  waxes  are  apt  to  possess  a 
crystalline  grain  which  spoils  the  appearance  of  the  candle,  and 
when  bleached  by  chlorine,  to  give  off  fumes  of  hydrochloric  acid 
when  burnt,  owing  to  the  formation  of  chloro-substitutioii  com- 
pounds during  the  bleaching  process.  Paraffin  wax  and  the 
analogous  waxy  hydrocarbons  obtained  from  ozokerite,  &c., 
require  no  further  treatment  for  caiidlemaking  other  than  the 
pressing  and  purifying  processes  gone  through  during  their 
manufacture  for  the  purpose  of  raising  the  melting  point  to  the 
requisite  extent  (compare  p.  230).  The  isolation  of  solid  free 
fatty  acids  from  natural  glycerides,  however,  is  a  somewhat 
complex  operation  capable  of  being  carried  out  in  several  ways. 


MANUFACTURE   OF    "STEARINE." 

The  numerous  processes  proposed,  and  more  or  less  actually 
used  on  a  manufacturing  scale  for  the  isolation  of  solid  fatty 
acids  from  appropriate  glycerides,  may  be  classified  under  the 
following  heads  :  — 

1.  Processes  where  the  glycerides  are  saponified  by  alkalies, 
alkaline  earths  (such  as  lime),  or  other  suitable  basic  materials, 
by  boiling  under  ordinary  pressure ;  to  effect  which  operation  a 
more  or  less  considerable  excess  of  base  is  usually  found  necessary 
in  order  to  complete  the  saponification. 

2.  Processes  analogous  to  the  preceding,  except  that  the  opera- 
tion is  carried  out  at  a  somewhat  higher  temperature  obtained 
under  increased  pressure  ;  excess  of  base  is  in  this  case  unneces- 
sary,   for,    in    general,    practically    complete    saponification   and 
hydrolysis  can  be  thus  easily  brought  about  even  when  consider- 
ably less  base  is  present  than  is  chemically  equivalent  to  the 
fatty  acids  formed,  and  although  the  temperature  does  not  rise 
sufficiently  high  to  decompose  any  considerable  fraction  of  the 
glycerol  set  free. 


MANUFACTURE    OF    STEARINE.  365 

3.  Processes  where  hydrolysis  is  effected  under  the  influence 
of  acids,    especially   sulphuric  acid ;    in  this  case  the  liberated 
acids  are  usually  distilled  over  by  the  aid  of  superheated  steam, 
so  as  to  separate  them  from  nonvolatile  pitchy  matters  formed 
as  bye  products  ;    in   Bock's  process   (infra}   this  distillation  is 
unnecessary.     More  or  less  glycerol  is  usually  destroyed  by  the 
action  of  the  acid. 

4.  Processes   where    hydrolysis   is   brought  about  under  the 
influence  of  water  alone   (under   great  pressure,    or    as    highly 
superheated   steam).       In  these  processes  the  glycerol  is  often 
largely  destroyed  by  the  heat  (sometimes  completely  so),  a  much 
higher  temperature  being  requisite  than  in  the  case  of  methods 
of  the  second  class. 

The  Chevreul-Milly  Process  —  Alkaline  Saponiflcation 
Process  in  Open  Pans  under  Ordinary  Pressure. — The  first 
attempts  to  utilise  solid  free  fatty  acids  for  candle  material,  were 
made  about  1825  by  Chevreul  and  Gay  Lussac,  employing 
alkalies  (potash  and  soda)  to  effect  the  saponification  of  tallow ; 
for  a  variety  of  reasons,  this  process  proved  to  be  commercially  a 
failure  ;  but  a  few  years  later,  by  substituting  lime  for  alkalies 
and  otherwise  employing  more  suitable  arrangements,  M.  de 
Milly  succeeded  in  making  the  manufacture  of  "  stearine " 
candles  from  tallow  a  sufficiently  remunerative  undertaking  to 
render  it  a  practical  industry.  As  carried  out  at  the  present 
day,  the  process  differs  little  in  essential  points  from  what  it  was 
more  than  half  a  century  ago,  the  chief  differences  lying  in  the 
scale  on  which  the  operations  are  effected,  and  the  frequent  use 
of  mixtures  of  vegetable  and  other  substances  with  tallow  (e.g.,  a 
mixture  of  palm  oil  and  tallow  or  other  suitable  fatty  matters) 
instead  of  tallow  only,*  a  better  quality  of  mixed  fatty  acids 
being  thereby  usually  obtained — i.e.,  a  mixture  which  allows  the 
solid  acids  to  crystallise  and  "granulate"  more  readily,  so  as  to 
be  more  easily  pressed  for  the  separation  of  liquid  acids. 

The  fatty  matters  being  generally  purchased  in  casks,  by  means 
of  a  steam  jet  applied  at  the  bunghole,  the  fats  are  melted  out 
into  a  tank,  whence  they  are  pumped  or  run  by  gravitation  into 
the  decomposing  pan,  usually  constructed  of  wooden  staves 
(preferably  of  oak)  strongly  bound  together,  and  forming  a  large 
tub  or  tun,  sometimes  lined  with  sheet  lead.  This  is  provided 
with  a  stirring  arrangement,  consisting  of  a  central  vertical  shaft 
with  arms  carrying  paddles  and  rakes,  so  as  to  intermix  the 
contents  thoroughly  (Fig.  78).  Quicklime,  in  the  proportion  of 
12  to  15  pounds  per  100  of  fat,  is  mixed  with  water  to  a  cream 
and  run  into  the  tun,f  and  the  whole  heated  up  by  steam  blown 

*  In  France  the  use  of  palm  oil  is  much  less  frequent  than  in  Britain,  thus 
leading  to  some  slight  differences  between  many  kinds  of  French  "stearine," 
as  compared  with  British. 

t  Assuming  the  mixture  of  fatty  matters  to  have  a  mean  saponification 


3G6 


OILS,    FATS,    WAXES,    ETC. 


in  through  a  perforated  horizontal  coil  at  the  bottom  of  the  tub, 
or  a  series  of  jets  distributed  over  the  bottom,  and  the  whole 
kept  agitated  for  some  hours,  [a  cover  being  placed  over  the 

tub  to  keep  in  splashes, 
and  steam  being  blown 
through  gently  so  as  to 
keep  the  whole  boiling. 
Glycerol  is  thus  set  free, 
and  a  mixture  of  lime- 
salts  formed  (mostly 
stearate,  palmitate,  and 
oleate),  practically  in- 
soluble in  water,  and 
solidifying  on  cooling  to 
a  hard  mass  known  as 
"rock;"  the  aqueous 
glycerol  solution  or 
"sweet  water"  is  run 
off  and  utilised  for 
glycerol  extraction. 

To   isolate    the   fatty 
acids,  the  rock  is  boiled 


Fig.  78. 


up  in  a  lead-lined  vat  with  steam,  diluted  sulphuric  acid  bein^ 
added  in  slight  excess  of  the  quantity  requisite  to  saturate 
all  the  lime  present.*  Sulphate  of  calcium  separates  out, 
whilst  the  free  fatty  acids  swim  up  to  the  top  ;  after  standing 
and  cooling  somewhat,  these  are  skimmed  off  and  boiled  up, 
firstly  with  highly  dilute  sulphuric  acid  to  decompose  the 
last  traces  of  lime  soap,  and  then  with  water,  using  wet  steam, 
so  as  thoroughly  to  wash  out  all  sulphuric  acid  and  admixed 
mineral  matters.  Finally,  the  fluid  fatty  acids  are  transferred 
to  shallow  cooling  pans,  such  as  the  series  indicated  in  Figs. 
79  and  80.  Here  the  melted  fatty  acids  are  run  from  a 
trough,  F,  through  nozzles,  D  D  D,  into  the  uppermost  of  the 
pans,  C  C  C,  supported  by  a  wooden  framework,  A  A,  and  iron 
crossbars,  B  B  B.  When  the  pans  are  filled,  the  stream  of  melted 

equivalent  of  280,  the  quantity  of  liine  (CaO)  theoretically  equivalent  to  the 
fatty  acids  formed  would  be  28  parts  per  280,  or  10  per  cent.  ;  with  fatty 
matters  of  higher  saponification  equivalent,  proportionately  less  lime  would 
be  required,  and  vice  versa.  Some  excess  of  lime,  however,  is  requisite  in 
order  to  ensure  tolerably  complete  action  ;  moreover,  in  practice,  quicklime 
is  not  pure  CaO,  a  little  moisture,  calcium  carbonate,  and  more  or  less 
siliceous  and  clayey  matter  being  present,  all  of  which  are  inert  so  far  as 
effecting  saponification  is  concerned.  A  first  class  quicklime,  made  from  a 
pure  limestone,  may  contain  (when  freshly  burnt)  some  95  per  cent,  of  CaO 
(exclusive  of  calcium  carbonate) ;  but  85  to  90  per  cent,  is  more  nearly  the 
usual  average,  and  less  with  very  poor  limes. 

*  For  every  56  parts  of  actual  lime,  CaO,  used,  98  parts  of  actual 
sulphuric  acid,  HJ304,  are  required  ;  roughly,  2  parts  of  B.O.  V.  (brown  oil 
of  vitriol)  to  1  of  quicklime. 


STEARINE  ;    CRYSTALLISATION. 


367 


matter  is  shut  off  by  means  of  the  spigot,  E.  In  these  cooling 
pans  they  solidify  to  a  semicrystalline  mass  on  cooling  and  stand- 
ing ;  for  the  purpose  of  pressing  out  the  fluid  acids,  this  solidifi- 
cation is  best  allowed  to  take  place  in  metal  dishes,  so  that  the 
solid  cakes  formed  are  obtained  in  the  form  of  slabs  about  an 
inch  or  three-fourths  inch  thick,  and  of  such  size  as  to  fit  into  the 
cake  boxes  of  the  hydraulic  press  used ;  the  temperature  during 


«•  M    U   4! 


Fig.  79. 


Fig.  80. 


this  period  should  lie  between  21°  and  32°  C.  (70°  to  90°  R),  so 
that  whilst  the  "seeding"  or  crystallisation  of  the  solid  acids 
(mostly  stearic  and  palmitic)  may  take  place  completely,  as  little 
oleic  acid  as  possible  may  be  retained  in  the  body  of  the  crystals 
formed.  The  slabs  of  "  separation  cake "  finally  consist  of  a 
spongy  mass  of  granular  or  crystallised  solid  acids,  with  liquid 
oleic  acid  (containing  solid  acids  and  colouring  matters  in  solu- 
tion) disseminated  through  the  interstices.  By  enveloping  them 
in  press  cloths,  and  placing  them  in  the  cake  boxes  of  a  hydraulic 
press,  the  brownish  liquid  acids  are  gradually  squeezed  out,  and 
the  comparatively  colourless  solid  crystals  retained.  Instead  of 
directly  pressing  the  granulated  cakes,  it  is  often  preferable  to 
rasp  them  into  shreds  by  a  machine,  and  to  press  the  raspings ; 
a  more  complete  expression  of  liquid  acids  is  thus  brought  about. 
The  press  cake  left,  however,  still  retains  a  certain  amount  of 


368 


OILS,    FATS.    WAXES,    ETC. 


liquid  acids,  rendering  its  fusing  point  too  low ;  to  remove  these 
the  press  cakes  are  melted  by  steam,  cast  afresh  into  slabs  in 
shallow  trays,  allowed  to  stand  to  granulate  at  a  temperature  of 
about  30°  C.,  rasped  to  coarse  powder,  and  again  pressed  in  a 
different  machine  where  the  cake  boxes  are  heated  by  the  regu- 
lated admission  of  steam  into  the  plates,  in  the  body  of  which 
channels  are  hollowed  out  for  the  purpose.  Fig.  81  represents 
n  form  of  horizontal  hot  press  thus  arranged,  steam  being  ad- 
mitted to  the  plates  by  the  pipes,  E  E.  A  A  A  represent  the 
packets  of  raspings  undergoing  pressure  ;  B  the  piston  of  the 
hydraulic  ram  working  in  the  cylinder,  C  ;  D  the  framework  ; 
P  a  chain  whereby  the  plates  are  drawn  asunder  for  the  removal 
of  the  cakes  when  the  operation  is  finished  ;  G  water  supply 
pipe  to  ram  cylinder  from  accumulator.  The  temperature  of  the 
hot  press  varies  somewhat  with  the  kind  of  material  employed, 
but  is  generally  not  far  from  50°  (122°  F.)  for  stearine  of  high 


JIM. 


Fig.  81. 

melting  point ;  for  inferior  stearine  melting  more  easily,  the 
temperature  is  proportionately  lower. 

The  hot  press  cake  finally  obtained  is  melted  by  means  of  steam 
along  with  a  little  water  acidulated  with  sulphuric  acid,  and  then 
vigorously  agitated  with  the  acid  fluid  for  some  time  for  the 
purpose  of  removing  traces  of  lime  salts  still  retained ;  finally 
the  acid  liquor  is  run  off,  and  several  successive  boilings-up 
•carried  out  with  plain  water.  The  purified  mixture  of  stearic 
and  palmitic  acids  is  then  cast  into  blocks  for  use  in  the  candle 
factory ;  small  quantities  of  vegetable  wax,  beeswax,  £c.,  are 
sometimes  added  to  "break  the  grain" — i.e.,  to  prevent  the 
formation  of  visibly  large  crystals  during  solidification. 

Even  when  the  fatty  matters  employed  are  highly  rancid  and 
impure,  an  almost  perfectly  white  "  stearine  "  can  be  thus  manu- 
factured by  the  lime  process.  The  yield  of  pure  solid  hot  pressed 
acids,  however,  is  materially  influenced  by  the  presence  and 


OPEN    PAN    PROCESS. 


369 


nature  of  abnormally  large  proportions  of  oleine  (existing  in 
softer  fats,  &c.)  or  other  substances  (e.g.,  woolgrease),  not  only 
on  account  of  the  diminution  in  amount  of  solid  fat  acids  present, 
but  also  because  of  the  increased  amount  of  these  acids  removed 
in  the  "red  oils"  (vide  infra). 

Fig.  82  represents  a  general  view  of  the  disposition  of  the 
apparatus  used  in  the 
saponification  of  fatty 
matters  by  the  open  pan 
process.*  A,  tub  from 
which  lime  is  emitted. 
B,  leadlined  vats  with 
steam  pipes  for  boiling 
lime  and  fats.  C,  similar 
decomposing  vats  where 
the  rock  is  boiled  with 
sulphuric  acid.  D  D,  rack 
holding  pans  for  caking 
mixed  acids.  E,  cold 
press.  F,  hydraulic 
pumps.  G,  pan  for  re- 
melting  press  cake.  H, 
hot  press.  I,  vat  for 
melting  hot  pressed 
stearine  for  final  wash- 
ing with  water  and  cast- 
ing into  blocks. 

Moinier  and  Boutigny 
modify  the  Chevreul- 
Milly  process  by  sub- 
mitting the  melted  tal- 
low, &c.,  to  a  preliminary 
treatment  with  hot  water 
and  a  current  of  impure 
sulphur  dioxide  (pro- 
duced by  the  action  of 
hot  sulphuric  acid  on 
sawdust,  charcoal,  &c.) ; 
after  an  hour  the  lime- 
cream  is  added  and  the 
whole  well  agitated, 
whereby  the  mass  in- 
creases in  consistence 
with  considerable  froth- 
ing, by  and  bye  becoming  pasty.  The  sulphur  dioxide  is  then 
shut  off  and  the  rock  finished  by  boiling  up  with  steam,  ifcc.,  as 
usual.  The  yield  of  fatty  acids  is  stated  to  be  thus  increased 
*  L.  Field,  Journ.  Soc.  Arts,  vol.  xxxi.,  p.  859. 

24 


370  OILS,    FATS,    WAXES,    ETC. 

by  some  4  per  cent.  The  hot  press  cake  is  finally  refined  by 
boiling  up  first  with  water  acidulated  with  sulphuric  acid,  then 
with  water  alone,  white  of  egg  (1  egg  per  100  Ibs.)  being  intro- 
duced whilst  boiling  so  as  to  coagulate  and  remove  impurities 
as  in  clarifying  coffee,  &c. 

On  p.  375  are  given  some  analyses  of  original  fatty  acid  mixture, 
cold  press  cake,  and  hot  press  cake,  £c.,  illustrating  the  eifect  of 
the  process  in  separating  oleic  acid  from  the  solid  fatty  acids, 
and  the  increment  inf melting  point  thus  effected.  The  hot  press 
grease  usually  contains  enough  solid  fatty  acids  to  raise  its  fusing 
point  to  at  least  that  of  the  original  mixture  of  fatty  acids  before 
cold  pressing ;  it  is  generally  worked  up  along  with  fresh  fatty 
acids  by  fusing  therewith  and  granulating  the  mixture  in  trays  for 
the  cold  press.  The  outer  edges  of  the  hot  press  cake  retain  some 
amount  of  more  fusible  grease,  and  are  therefore  usually  pared 
off  and  worked  up  along  with  the  rest  of  the  hot  press  grease. 

The  "red  oil"  or  "oleine"  running  from  the  cold  press  contains 
a  considerable  quantity  of  palmitic  and  stearic  acids  in  solution, 
the  precise  amount  depending  on  the  temperature  at  which  the 
pressing  is  conducted ;  on  chilling  somewhat,  more  or  less  solid 
fatty  acids  separate,  usually  in  a  finely  divided  form.  When  it 
is  desired  to  obtain  red  oils  containing  as  large  a  proportion  of 
oleic  acid  and  as  little  solid  acids  as  possible,  the  oil  is  chilled 
and  the  resulting  somewhat  pasty  mass  passed  through  a  filter 
press,  such  as  shown  in  Figs.  56,  59,  the  greasy  solid  fatty 
acids  thus  obtained  being  worked  up  with  fresh  batches  of  the 
original  mixture  of  acids ;  for  the  manufacture  of  oleine  soap 
this  treatment  is  not  indispensable,  but  inasmuch  as  the  solid 
fatty  acids  are  considerably  more  valuable  than  the  fluid  ones, 
it  is  obviously  desirable  to  obtain  as  large  a  proportion  of  the 
former  as  possible.  For  the  same  reason  it  is  essential  that  the 
saponification  of  the  fats  used  should  be  as  nearly  complete  as 
possible,  not  only  because  all  the  stearic  and  palmitic  glycerides 
that  escape  saponification  are  lost  so  far  as  solid  fatty  acids  are 
concerned  (being  expressed  fluid  during  the  pressing  operations), 
but  also  because  their  presence  tends  to  prevent  the  proper 
crystallisation  of  the  solid  acids,  and  thus  to  increase  the  pro- 
portion of  these  contained  in  the  red  oils.  In  actual  practice,  it 
is  impossible  to  carry  the  decomposition  in  open  pans  to  absolute 
completeness  without  seriously  prolonging  the  operation,  which 
entails  extra  cost ;  so  that  a  few  per  cents,  (and  sometimes  much 
more,  up  to  10  or  12  per  cent.)  of  the  glycerides  used  are  gener- 
ally left  undecomposed  in  the  rock,  ultimately  finding  their  way 
into  the  red  oils. 

When  the  tallow  used  has  been  adulterated  by  mixing  in 
woolgrease  or  similar  material  containing  unsaponifiable  matters, 
these  substances  are  generally  also  ultimately  contained  in  the 
red  oils,  thereby  diminishing  the  proportion  of  "  stearine '* 


COMPOSITION    OF    "ROCK."  371 

obtainable,  partly  because  of  the  smaller  proportion  of  solid 
glycerides  present  in  the  adulterated  tallow,  and  partly  because 
the  presence  of  woolgrease,  like  that  of  unsaponified  fat,  tends  to 
interfere  with  the  crystallisation  of  the  acids,  and  hence  causes 
the  red  oils  to  retain  more  solid  acids.  Moreover,  when  the  red 
oils  are  made  into  soap,  a  deteriorating  effect  (for  certain  pur- 
poses) is  brought  about  in  the  resulting  soap  j  on  solution  in 
water  and  standing,  soap  containing  such  unsaponifiable  matter 
is  apt  to  throw  up  an  oily  film,  rendering  the  solution  liable  to  spot 
and  grease  goods  rinsed  through  the  soap  solution.  Accordingly, 
it  is  preferable  to  buy  tallow  by  analysis,  the  price  varying  accord- 
ing to  the  proportion  of  solid  fatty  acids  present  (estimated  by 
Dalican's  process,  p.  74,  or  otherwise)  and  deductions  being 
made  for  unsaponifiable  constituents.  As  yet,  however,  this  sys- 
tem does  not  seem  to  have  been  widely  adopted  in  this  country. 
Composition  of  "Rock." — The  following  analyses  represent 
the  general  composition  of  open  pan  "rock"  as  obtained  on  the 
manufacturing  scale ;  A  being  normal  rock  made  from  genuine 
tallow  mixed  with  about  one-fourth  its  weight  of  palm  oil ;  and 
B  rock  from  tallow  adulterated  with  woolgrease  containing  a 
considerable  amount  of  cholesterol  and  other  unsaponifiable 

matters  : — 

A  B 


Lime  present  as  lime  soap  (CaO), 

Lime  used  in  excess  (CaO), 

Fatty  anhydrides*  present  as  lime  soap, 

Unsapoiiined  glycerides,    . 

Unsaponifiable  organic  matter, 

Water  and  carbonic  acid  (C02),  combined  with 

the   excess   of    lime;  sand    and    grit,    &e 

uncombined  water  (moisture), 


7-50  6-27 

1-95  241 

73-30  61-20 

5-55  8-40 

2-75  12-00 


8-95  9-72 


100-00     100-00 

Since  100  parts  of  triglycerides  of  mean  molecular  weight  near 
285,  represent  about  92  parts  fatty  anhydrides,  the  fatty  anhy- 
drides present  in  these  two  samples  represent  respectively  about 
80  and  66  parts  of  original  glycerides  per  100  of  rock  j  hence 
the  proportion  of  glycerides  originally  used  which  remain 

5*55 

unsaponified  are  (A)   -7-  -  x    100   =   G'5   per   cent,    and 

v    '    80  +  5-55 


(B)— —  -  x   100  =    11 '3  per  cent. —  i.e.,    in   the   first  case 

6t>      +      O"4:0 

about  Jg-,  and  in  the  second  about  l,  of  the  original  glycerides 
escaped  sapoiiification. 

*  "Fatty   anhydrides "=  fatty   acids,    less    an   equivalent   of   water — 
p.g.,  in  the  case  of  stearic  anhydride  ^      j85Q  J-  0  ;  so  that  the  sum  of  the 

fatty  anhydrides  and  the  lime  combined  with  them  as  lime  soap,  represents 
the  actual  amount  of  lime  soap  present.  In  the  above  two  instances  the 
amounts  of  lime  soap  are  (A)  73'30  +  7'50  =  80  35 ;  (B)  61'20  +  6'27  =  67 '47. 


372  OILS,    FATS,    WAXES,    ETC. 

Analysis  of  Hock. — This  is  conveniently  effected  by  taking 
a  known  weight  of  an  average  sample  and  boiling  it  with  water 
to  which  an  excess  of  standard  acid  (preferably  hydrochloric)  has 
been  added,  until  completely  decomposed ;  on  standing,  the 
liberated  fatty  acids,  £c.,  form  a  cake  on  the  top,  which  is  care- 
fully removed,  dried,  and  weighed  ;*  the  free  fatty  acids  therein 
are  then  titrated  in  alcoholic  solution  with  standard  alkali,  and 
the  examination  for  admixed  glycerides  and  unsaponifiable 
matters  proceeded  with,  as  in  the  case  of  separation  cake  (vide 
infra,  p.  378).  The  excess  of  acid  in  the  watery  fluid  is  back 
titrated,  so  as  to  obtain  the  acid  neutralised  by  the  total  lime 
present,  which  is  thence  calculable ;  whilst  the  lime  present 
as  lime  soap  (combined  with  fatty  acids)  is  similarly  calculated 
from  the  amount  of  alkali  neutralised  by  the  fatty  acids.  For 
example,  10  grammes  of  a  given  sample  of  rock  were  boiled  with 
water  and  50  c.c.  of  normal  acid  ;  on  back  titration  16 '7  c.c.  were 
found  to  be  unneutralised ;  hence  33*3  c.c.  were  neutralised, 
equivalent  to  0-932  CaO  =  9*32  per  cent,  of  total  lime.  The 
separated  fatty  acids,  &c.,  weighed  8-215  grammes,  and  neutralised 
25'9  c.c.  of  normal  alkali,  equivalent  to  0*725  gramme,  or  7 "25 
per  cent,  of  CaO  ;  whence  0-932  -  0-725  =  0*207  gramme  of 
excess  of  lime  was  present,  or  2*07  per  cent.  On  further  ex- 
amination (p.  378)  the  separated  fatty  acids  were  found  to  con- 
tain 0*535  gramme  of  unsaponified  glycerides  and  0*235  grammes 
of  unsaponifiable  matters.  Hence  the  actual  fatty  acids  pre- 
sent in  the  8*215  grammes  of  cake  obtained  amount  to 
8*215  -  (0*535  +  0*235)  =  7-445  grammes.  In  order  to  reckon 
the  fatty  anhydrides  equivalent  to  this  amount  of  fatty  acids, 
18  parts  of  water  must  be  subtracted  for  56  of  CaO  combined 

1  R 
with  them    as    lime    soap — i.e.,  ^  x  0-725  =  0-233  gramme  of 

water  must  be  subtracted,  leaving  7-445  -  0-233  =  7'212  grammes 
of  fatty  anhydrides  present  as  lime  soap. 
Hence  the  whole  analysis  is — 

Lime  present  as  lime  soap  (CaO),    .  0'725  grammes  =  7'25  per  cent. 

,,     in  excess,        ....  0'207  ,,  =  2D7        „ 

Fatty  anhydrides   present  as   lime 

soap 7-212  ,,  =  72-12        ,, 

Unsaponitied  glycerides,           .         .  0'535  ,,  =  5*35        ,, 

Unsaponifiable  matter,    .         .         .0  235  ,,  =  2 '35        ,, 

Combined  water,  CC>2,  sand,  mois- 
ture, &c.  (by  diflerence),       .         .  1'086  „  =  10'SG 

10-000  100-00 

Total  lime  soap  present,     7 "25  +  72*12  =   79*37  per  cent. 

Total  lime  present,        .     7 '25  +    2  "07  =     9  -32       „ 

*  If  the  quantity  is  too  small  for  accurate  determination  in  this  way  the 
liberated  fatty  acids,  &c. ,  may  be  dissolved  by  ether,  and  the  ethereal 
solution  separated  and  evaporated,  &c.,  as  in  the  parallel  case  of  soap 
analysis  (Chap,  xxi.) 


AUTOCLAVE    PROCESS.  373 

Milly  Autoclave  Process — Saponiflcation  with  Alkalies 
(Lime)  under  Increased  Pressure. — As  practically  carried 
out,  this  process  is  virtually  a  combination  of  the  previous 
process,  and  that  subsequently  described  due  to  Tilghmanns, 
where  fats  are  hydrolysed  by  the  action  of  water  under  high 
pressure.  The  tallow  and  palm  oil  or  other  fatty  mixture  is 
pumped  into  a  stout  copper  pressure  vessel  or  autoclave,  and  lime 
made  into  a  thin  cream  with  water  added  in  much  smaller  pro- 
portion than  in  the  open  pan  process,  usually  2  to  3  parts  of 
lime  per  100  of  fat,  or  somewhere  about  one-quarter  of  the 
theoretical  amount  instead  of  an  excess.  High  pressure  steam  is 
then  gradually  blown  in  from  a  boiler  until  the  pressure  amounts 
to  at  least  7  or  8  atmospheres,  and  preferably  12  to  15,  especially 
when  tallow  only  is  used,  as  in  many  Continental  factories. 
After  some  hours  continuance  of  digestion  under  pressure  the 
fat  is  practically  completely  saponified  and  hydrolysed,  partly  by 
the  lime,  partly  by  the  action  of  water  only,  the  presence  of  the 
lime  soap  formed  by  the  saponification  greatly  facilitating  the 
hydrolysis  ;  the  mixed  "  sweet  water,"  fatty  acids,  and  lime  soap 
are  blown  off  into  a  tank,  where  the  latter  separate  from  the 
watery  glycerol  solution,  and  are  then  treated  with  sulphuric 
acid  precisely  as  in  the  open  pan  process,  saving  that  as  much 
less  lime  is  used,  a  proportionately  smaller  quantity  of  acid  is 
requisite.  The  further  operations  of  separating  solid  fatty  acids 
by  pressure,  etc.,  are  identical  in  the  two  processes. 

The  remarks  above  made  respecting  the  objectionable  results 
brought  about  when  any  considerable  amount  of  glycerides  escapes 
saponification,  and  when  the  tallow  is  adulterated  with  wool- 
grease  or  other  unsaponifiable  matters,  obviously  apply  equally 
in  the  present  case.  As  regards  the  former  point,  the  following 
figures  were  obtained  by  the  author  in  a  set  of  experiments  on  a 
manufacturing  scale  made  with  the.  object  of  tracing  out  the 
effect  of  increased  time  in  diminishing  the  amount  of  unsaponified 
grease.  A  series  of  charges  was  worked  off  in  the  same  auto- 
clave, the  mixture  of  fats  (tallow  and  palm  oil),  and  the  proportion 
of  lime  used,  and  the  pressure  being  as  nearly  as  possible  the 
same  throughout,  but  the  times  being  different.  The  fatty  acids 
obtained  (after  separation  from  lime  by  sulphuric  acid)  were 
analysed  so  as  to  obtain  the  data  for  determining  the  proportion 
of  grease  unsaponified  during  the  digestion.  The  figures  ulti- 
mately obtained  on  averaging  a  number  of  trials  were — 


Time  in  Hours. 

Unsaponified  Grease  Reckoned  per  100 
parts  Originally  Employed. 

4* 
5| 

74 

9-4 
5-8 
3-1 

374 


OILS,    FATS,    WAXES,    ETC. 


During  the  first  hour  or  two  the  rate  of  decomposition  of  the 
fats  employed  was  rapid,  from  f  to  ^  being  converted  at  the  end 
of  2  hours  ;  subsequently  the  action  was  much  slower,  becoming 
practically  complete  at  the  end  of  6  to  6J  hours,  not  more  than 
about  -Jg-  then  remaining  unconverted. 

The  following  analyses  indicate  the  composition  of  the  "  rock  " 
obtained  by  the  autoclave  process ;  they  principally  differ  from 
those  above  cited  for  open  pan  rock,  in  that  whereas  in  the  open 
pan  process  excess  of  lime  is  used,  so  that  the  rock  contains  all 
the  fatty  acids  as  lime  soap  ;  in  the  autoclave  lime  process  a 
deficiency  of  lime  is  employed,  so  that  the  fatty  acids  are  obtained 
partly  as  lime  soap  and  partly  as  free  acids  : — 


1      L 

II. 

in. 

Lime  present  as  lime  soap  (CaO), 

3-20 

2-38 

2-52 

Fatty  anhydrides  combined  therewith, 
Free  fatty  acids,        .... 

31-90 
57*75 

22-62 
58-50 

23-94 
66-30 

Unsaponified  glycerides,  . 

5-90 

G-60 

3-20 

Unsaponifiable  organic  matter, 

0-70 

1-33 

1-85 

Grit  and  mineral  matters  ;  water,     . 

0-55 

8-57 

2-19 

100-00 

100-00 

100-00 

100  parts  of  the  fatty  glycerides  used  originally  represent 
about  95  of  free  fatty  acids  and  92  of  fatty  anhydrides,  whence 
100  parts  of  rock  represent  in  these  three  cases  respectively  about 
95,  86,  and  96  parts  of  fatty  glycerides  that  have  been  saponified 
and  hydrolysed ;  whence  the  proportions  of  glycerides  not  acted 
upon  are — 


I. 


II. 


III. 


5-90 

95  +  5-90 

6-60 
86  +  C'60 

3-20 

96  +  32 


100  =  5-8  per  cent. 


x  100  =  7-1 


x  100  =  3-2 


In   general,   with  unadulterated  tallow,  the  autoclave  process, 
properly  worked,  saponifies  and  hydrolyses  about  95   per  cent. 


of  the  glycerides  used,  leaving  some  5  per  cent 


unacted 


on ;  if,  however,  too  low  a  pressure  be  applied,  the  proportion  of 
undecomposed  glycerides  may  amount  to  considerably  more  than 
this  unless  a  proportionately  longer  time  be  allowed,  involving 
greater  cost  for  fuel,  labour,  &c. 

The  "  separation  cake  "  or  mixture  of  fatty  acids  obtained  by 
decomposing   with   sulphuric    acid  the   "rock"   formed   in  the 


IODINE   TEST   APPLIED   TO    SEPARATION    CAKE,    ETC. 


375 


autoclave  or  open  pan  process  consists  of  the  solid  fatty  acids 
produced  (chiefly  stearic  and  palmitic) ;  the  liquid  acids  (mainly 
oleic) ;  and  whatever  undecomposed  glycerides  and  unsaponifiable 
organic  matters  may  be  present ;  the  latter  two  ingredients 
obviously  vary  with  the  degree  of  perfection  or  imperfection 
attained  in  saponification,  and  with  the  purity  of  the  materials. 
The  ratio  between  solid  and  liquid  fatty  acids  also  varies  some- 
what with  the  character  of  the  tallow  and  other  fatty  matters 
used;  in  general,  it  is  not  far  from  2  to  1.  In  examining  such 
materials,  the  author  has  found  the  '"'iodine  test"  (pp.  177,  179, 
et  seq.)  particularly  useful,  especially  in  the  case  of  press  cake  in 
different  stages  of  pressing.  The  further  the  pressing  (hot  after 
cold)  is  carried,  the  smaller  the  quantity  of  oleic  acid  left  in  the 
"stearine;"  but  no  amount  of  hot  pressing  will  completely 
eliminate  "  unsaturated "  acids,*  from  1  to  2  per  cent,  being 
retained  even  when  the  pressing  has  been  carried  to  the  utmost 
possible  extent  permissible  for  commercial  purposes  in  the  pre- 
paration of  articles  of  exceptionally  high  melting  points,  and 
larger  proportions  up  to  4  or  even  5  per  cent,  in  products  less 
thoroughly  hot  pressed.  Even  crystallisation  several  times  from 
alcohol  of  a  mixture  of  palmitic  and  stearic  acid  does  not  succeed 
in  removing  all  the  oleic  or  other  iodine-absorbing  acid  present. 
Thus  the  following  typical  figures  may  be  cited,  obtained  by  the 
author  with  the  fatty  acids  manufactured  from  a  mixture  of 
tallow  and  palm  oil : — f 


Percentage  of  Oleic 
Acid  by  Iodine  Test. 

Melting  Point  in 
Capillary  Tube. 

Separation  cake  (mixture  of  fatty  acids 
before  pressing),         .... 

32-0 

Cold-pressed  cake,          .... 

11  -5 

52°  -8  C. 

Once  hot  pressed,           .         .         .         .    . 

5-6 

54°  -2 

Twice         ,,                      . 

2-5 

56°  -1 

Three  times  hot  pressed, 

1-3 

56°  '2 

,,           twice    recrystallised    from 

alcohol,  .... 

0-8 

56°  -25 

Red  oils  (oleine)  from  cold  pressing, 

71-5 

Grease  from  hot  pressing, 

14-9 

51°  -6 

The  percentage  of  solid  fatty  acids  contained  in  red  oils  can  be 
deduced  approximately  from  the  determination  of  the  oleic  acid, 
reckoning  111 -02  parts  of  acid  per  100  of  iodine  consumed,  as 
indicated  by  the  equation — 

*  Possibly  isoleic  acid  (m.p.  45°),  and  not  oleic  acid,  remains. 

t  When  a  pressed  stearine  is  examined,  presumably  only  containing  a 
small  percentage  of  oleic  acid,  5  grammes  may  be  conveniently  taken  for 
analysis  ;  on  the  other  hand,  with  a  substance  containing  a  high  percentage 
of  oleic  acid,  proportionally  less  should  be  weighed  up,  usually  from  0'2 
to  O4  gramme. 


376  OILS,    FATS,    WAXES,    ETC. 

Oleic  Acid.  Saturated  Iodine  Addition 

Product. 

Ci8H3402  +  I2  C]8H34T202. 

If  the  percentage  of  unsaponified  grease  and  unsaponifiable 
organic  matters  present  be  known  =  a,  and  that  of  oleic  acid 
thus  determined  =  6,  the  percentage  of  solid  fatty  acids  is 
approximately  100  -  (a  +  b). 

Muter' s  process  for  the  determination  of  the  proportion  of 
oleic  acid  present  in  a  mixture  of  that  substance  with  solid  fatty 
acids  (stearic  and  palmitic)  is  based  on  the  solubility  of  lead 
oleate  in  ether.  In  the  case  of  a  glyceride,  a  quantity  of  sub- 
stance not  exceeding  1*5  grammes  is  saponified  with  excess  of 
alcoholic  potash  ;  with  free  fatty  acids  it  is  dissolved  in  the  same 
solvent  ;  water  is  added  and  the  alcohol  boiled  off;  dilute  acetic- 
acid  is  then  added  to  neutralise  excess  of  alkali,  until  a  decided 
permanent  turbidity  is  produced,  and  then  dilute  caustic  potash 
with  continuous  agitation  until  the  liquid  just  clears  again.  The 
clear  solution  is  then  precipitated  by  lead  acetate  in  slight 
excess,  and  stirred  until  the  lead  soap  settles  thoroughly ;  the 
supernatant  liquor  is  poured  off,  and  the  precipitate  washed  by 
boiling  with  a  large  bulk  of  distilled  water  and  decanting. 
Perfectly  neutral  lead  stearate  +  palmitate  +  oleate  is  thus 
obtained;  the  precipitate  is  transferred  to  a  flask  of  about  100  c.c. 
capacity  and  digested  for  some  hours  (with  frequent  agitation) 
with  absolute  ether ;  the  ethereal  solution  of  lead  oleate  is 
filtered  into  a  stoppered  graduated  tube  holding  250  c.c.,  and  the 
filtrate  and  washings  decomposed  by  agitation  with  about  20  c.c.  of 
a  mixture  of  1  volume  strong  hydrochloric  acid  and  2  volumes 
water.  Finally,  a  known  fraction  of  the  ethereal  fluid  is  drawn 
off  and  evaporated  to  dryness ;  whence  the  weight  of  oleic  acid 
is  deduced.  The  ethereal  solution  is  conveniently  drawn  off  by 
means  of  a  side  tap  fixed  to  the  graduated  tube  about  one-fifth  of 
the  way  up  from  the  bottom,  so  as  to  be  above  the  level  of  the 
acid  watery  fluid  ("Muter's  oleine  tube");  or  it  may  be  blown 
off  by  the  washbottle  device  (p.  120). 

De  Schepper  and  Geitel  have  constructed  the  table  quoted  on 
p.  377,  exhibiting  the  relative  proportions  of  commercial  "oleine" 
(impure  oleic  acid)  of  solidifying  point  5° -4,  and  commercial 
"  stearine "  (stearic  and  palmitic  acids)  of  solidifying  point  48° 
present  in  a  sample  of  separation  cake  of  given  solidifying  point 
(compare  pp.  75,  76). 

The  "  filter  cake  "  obtained  from  the  red  oils  when  these  are 
chilled  and  passed  through  a  filter  press  varies  considerably  in 
composition ;  besides  particles  of  fibre  (derived  from  filter  press 
coverings,  &c.)  and  dust,  &c.,  filtered  out,  portions  of  unsaponified 
grease  separate  in  the  solid  state  from  the  cooled  red  oils,  and 
smaller  quantities  of  unsaponifiable  matters  (cholesterol,  &c.)  con- 
tained in  the  grease  originally  used. 


RED    OIL    FILTER    PRESS    CAKE. 


377 


Solidifying  Point  of 
Separation  Cake. 

Percentage  of  Commercial 

Stearic  Acid. 

Oleic  Acid. 

Degrees  C. 

5-4 

0 

100 

10 

2-5 

97-5 

15 

6-6 

93-4 

20 

12-1 

87-9 

25 

18-5 

81-5 

30 

27-2 

72-8 

32 

31-5                     68-5 

34 

36-6                     63-4 

36 

43-0                    57-0 

37 

46-9                     53-1 

38 

50-5                     49-5 

39 

54-5                     45-5 

40 

589                     41-1 

41 

63-3 

367 

42 

68-5 

31-5 

43 

73-5 

26-5 

44 

78-9 

21-1 

45 

83-5                     16-5 

46 

89-0                     ll'O 

47 

94-1 

5-9 

48 

100-0 

0 

The  following  analyses  represent  its  usual  composition  : — 


Free  fatty  acids,  solid,    . 

,,  ,,         liquid  (oleic  acid), 

Unsaponified  glycerides, 
Unsaponifiable  organic  matters, 
Fibres,  dust,  &c.,    .... 


54-2 

25-0 

11-2 

4-3 

5-3 

100-0 


51-4 

21-5 

12-3 

4-9 

9'3 

100-0 


Since  the  great  majority  of  the  unsaponified  glycerides  con- 
tained in  the  rock  find  their  way  into  the  red  oils,  whilst  these 
latter  constitute  the  smaller  half  of  the  fatty  acids  obtained  (the 
"  stearine "  amounting  to  upwards  of  50  per  cent,  of  the  total 
acids)  it  results  that  the  percentage  of  unsaponified  glycerides 
present  in  the  red  oils  is  usually  more  than  double  that  in  the 
separation  cake.  The  same  remark  applies  to  the  unsaponifiable 
organic  matters.  If  the  red  oils  be  distilled  by  means  of  super- 
heated steam  the  unsaponified  glycerides  present  mostly  become 
hydrolysed  during  the  operation,  so  that  "distilled  oleine"  is 
practically  free  from  glycerides.  On  the  other  hand,  a  small 
proportion  of  the  oleic  acid  becomes  decomposed  during  the 
process,  forming  hydrocarbons  (compare  p.  278),  so  that  the 
unsaponifiable  organic  matters  usually  become  notably  increased 
in  amount.  The  following  analyses  indicate  the  composition  of 


378 


OILS,    FATS,    WAXES,    ETC. 


different  samples  of  red  oils  and  "distilled  oleines,"  and  illustrate 
these  points  : — 


Red  Oils. 

Distilled  Oleines 

Tallow  and 

Tallow- 

Palm  Oil. 

only. 

Free  fatty  acids, 

86-5 

87-85 

90-0 

89-65 

Unsaponified  glycerides,    . 
Unsaponifiable  organic  matters,  \ 
hydrocarbons,  &c.,          .         .  / 

11-7 

1-8 

11-30 
0-85 

1-6 

8-4 

2-95 
7-40 

100-0 

100-00 

100-0     100-00 

Analysis  of  Red  Oils,  Separation  Cake,  and  Similar 
Products.  —  This  is  carried  out  substantially  in  the  way  indi- 
cated on  p.  162.  The  "free  acid  number,"  A,  being  determined, 
and  also  the  "  total  acid  number,"  K,  the  data  are  obtained  for 
calculating  the  percentage  of  free  fatty  acids  and  unsaponified 
glycerides  present  if  the  mean  molecular  weight  of  the  fatty  acids 
is  known  or  assumed.  The  unsaponifiable  organic  matters  being 
determined  (by  the  methods  described  on  p.  119)  and  the  per- 
centage of  these  constituents  subtracted  from  100  (as  also  that 
•of  any  water  or  other  foreign  substance  accidentally  present),  a 
sufficiently  close  approximation  to  the  truth  is  obtained  by 

multiplying  the  difference,  D,  by 


A.  -r  \&-  ~~  A  j  X 
/  TZ"         A  \ 

centage  of  free  fatty  acids,  and  by  -.— 


-  for  the  per- 
l-Oo 

x  1-05 

-7T-  for  that 


(K-A)x  1-05 

of  the  undecomposed  glycerides ;  for  if  E  be  the  mean  equivalent 
of  the  fatty  acids,  E  +  12-67  is  that  of  the  glycerides  (p.  165); 
and  as  E  usually  lies  between  255  and  285,  the  ratio  of  E  to 
E  +  12-67  will  lie  between  1  to  1-050  and  1  to  1-045,  and  may 
safely  be  taken  as  1  to  1  -05 ;  so  that  the  weights  of  free  fatty 
acids  and  glycerides  will  be  substantially  in  the  ratio  of  A  to 
(K-A)  x  1-05,  whence  the  percentages  will  be — 


Free  fatty  acids 
Glycerides 


A  +  (K  -  A)  x  1-05 ' 

(K  -  A)  x  1-05 
A  +  (K  -  A)  x  1^05  ' 


Thus  supposing  that  a  given  substance  contains  5  per  cent,  of 
unsaponifiable  matter,  &c.,  and  consequently  that  D  =  95  ;  if 
the  free  acid  number,  A,  be  found  =  175-0  and  the  total  acid 
number,  K,  =  195-0,  so  that  K  -  A  =  20,  the  composition  will 
be — 


ANALYSIS    OF    RED    OILS,    ETC.  379 

Free  fatty  acids     1?5  +  20°x  =  =      89*28 


20  x  1-05  21 


175  +  20  x      05  196 

Unsaponifiable  matters,  &c.,   .         .         .         .         =        5  '00 

100-00 


From  these  figures  it  results  that  the  value  of  E  is  close  to 
286;  for  1,000  parts  of  substance  contain  892 '8  of  free  fatty  acids 
neutralising  175-0  of  KOH  ;  whence 

175-0     :     56-1       :  :       892'8     :     x     =     2S6'2 

Similarly  the  mean  equivalent  of  the  glycerides  is  close  to 
286-2  +  12-67,  or  nearly  299. 

Several  attempts  have  been  made  to  substitute  metallic  oxides 
for  lime  in  the  autoclave  lime  process,  more  especially  magnesia 
and  zinc  oxide.  At  ordinary  pressure  these  bodies  usually  act 
upon  fatty  glycerides  (such  as  tallow)  appreciably  more  slowly 
than  lime,  probably  on  account  of  their  greater  insolubility  in 
water;  but  it  is  claimed  that  under  pressure  this  difference  is 
not  observed,  but  rather  the  contrary,  so  that  a  much  smaller 
proportion  of  zinc  oxide,  will  effect  the  saponification  and  hydro- 
lysis of  fatty  matter  than  is  necessary  in  the  case  of  lime  :  thus 
in  the  British  patent  specification  of  Poullain,  E.  F.  Michaud, 
and  E.  K  Michaud  (No.  5,112,  1882)  from  2  to  5  parts  of  zinc 
oxide  are  directed  to  be  used  per  1,000  of  fatty  matter  (0'2  to  0'5 
per  cent.),  heat  being  continued  for  3  to  4  hours  under  a  pressure 
of  100  to  130  Ibs.  (7  to  9  atmospheres).  It  is  claimed  that  the 
smaller  proportion  of  base  employed  renders  it  necessary  to  use 
much  less  acid  to  obtain  pure  free  fatty  acids  than  would  other- 
wise be  required  ;  whilst  for  certain  purposes — e.g.,  manufacture 
of  scouring  soaps — it  is  not  necessary  to  dissolve  out  the  zinc 
at  all.  As  regards  magnesia,  comparative  experiments  with 
lime  and  magnesia  show  that  the  action  of  the  latter  is  always 
inferior  to  that  of  the  former  (vide  Journ.  Soc.  Chem.  Industry, 
1893,  p.  163). 

A  somewhat  analogous  process  has  been  proposed,  where 
ammonia  is  used  as  saponifying  agent,  fatty  matters  and  aqueous 
ammonia  being  heated  together  under  pressure.  Ammonia  soaps, 
if  formed,  are  so  far  wanting  in  permanency  that  by  blowing 
steam  through  them  they  are  decomposed,  ammonia  passing  off 
(collected  for  use  over  again),  whilst  free  fatty  acids  and  glycerol 
solution  remain.  It  does  not  appear  that  this  system  has  as  yet 
been  adopted  so  largely  as  to  rank  as  an  established  practical 
manufacture;  but  if  sufficiently  complete  decomposition  is  obtain- 
able in  a  moderate  time,  a  priori  the  method  would  seem  to  be 
of  a  workable  character. 


380  OILS,    FATS,    WAXES,    ETC. 

Stein,  Berge,  and  de  Roubaix  have  patented  *  the  use  of 
solution  of  sulphurous  acid  or  alkaline  bisulphite  as  hydrolytic 
agent ;  from  2  J  to  3  per  cent,  of  solution  is  added  to  the  fat  in  a 
pressure  vessel,  and  the  temperature  raised  to  170°  to  180°, 
whereby  a  pressure  of  some  18  atmospheres  is  attained ;  the 
reaction  is  said  to  be  complete  in  about  9  hours.  The  tempera- 
ture should  not  exceed  200°  C. 

Hydrolysis  of  Fats  by  means  of  Sulphuric  Acid.— It  has 
long  been  known  that  free  fatty  acids  are  obtainable  from 
glycerides  by  acting  upon  them  with  sulphuric  acid,  the  glycerol 
being  largely  converted  into  glycerosulphuric  acid  (p.  144), 
subsequently  more  or  less  decomposed  by  the  heat,  and  the  fatty 
acids  being  to  some  extent  similarly  acted  upon,  especially  in  the 
case  of  oleic  acid.  The  "  Wilson  "  process  (sometimes  called  the 
"Dubrunfaut"  process),  the  outcome  of  various  methods  originally 
patented  in  England  by  Gwynne,  Jones,  and  Wilson  (Price  &  Co.) 
in  1840  to  1843,  substantially  depends  on  these  reactions,  with 
the  further  addition  of  purification  of  the  fatty  acids  by  distilla- 
tion with  superheated  steam ;  the  melted  fats  (more  especially 
palm  oil)  are  heated  in  a  stout  copper  vessel  (the  "  acidifier  ")  to 
about  300°  to  350°  F  =  149°  to  177°  C.,  by  means  of  superheated 
steam  ;  sulphuric  acid  is  then  run  in  to  the  extent  of  3  to  5  per 
cent.,  the  whole  intermixed,  and  allowed  to  stand  some  hours ; 
during  this  period  the  glycerides  are  broken  up,  and  foreign 
organic  matters  present  mostly  carbonised.  In  general,  the  less 
the  quantity  of  sulphuric  acid  used,  the  higher  is  the  temperature 
employed.  The  acid  mixture  is  then  run  off  and  boiled  up  with 
water  by  means  of  wet  steam,  so  as  to  wash  out  sulphuric  acid 
and  other  products  soluble  in  water;  after  standing  for  some 
hours  to  settle,  the  crude  fatty  acids  are  separated  and  heated  to 
about  240°  F.  (116°  0.)  to  complete  the  removal  of  water;  finally 
superheated  steam  at  a  higher  temperature  is  passed  through, 
the  precise  temperature  varying  with  the  nature  of  the  fatty 
matter  used,  but  being  usually  near  560°  F.  (294°  C.) 

Under  these  conditions  the  fatty  acids  are  volatilised,  and  are 
condensed  along  with  most  of  the  steam  in  a  series  of  copper 
serpentine  refrigerating  pipes  exposed  to  the  air,  the  escaping 
vapours  being  deodorised  as  far  as  possible  by  a  water  shower 
to  absorb  acrolein,  &c.,  and  subsequently  burned,  much  as  in  the 
somewhat  analogous  case  of  rendering  animal  fats  (p.  247).  The 
fatty  acids  thus  obtained  contain  a  much  larger  proportion  of 
solid  acids,  and  less  fluid  oleic  acid  than  those  obtained  by  the 
lime  saponification  process  from  the  same  material,  whether  by 
the  open  pan  or  autoclave  method ;  it  would  seem  very  probable 
that  this  is  due  to  the  transformation  by  the  action  of  sulphuric 
acid  of  oleic  acid  into  isoleic  acid  (melting  at  near  45°  C.),  as  in 
the  case  of  the  action  of  zinc  chloride  on  oleic  acid  (p.  142) ;  or, 
*  German  patent,  No.  61,329. 


SULPHURIC    ACID    PROCESSES. 


381 


possibly,  stearolactone  or  oxystearic  acid  is  formed.  According* 
to  Lant  Carpenter,*  tallow  which  will  only  yield  about  50  per 
cent,  of  its  weight  of 
candle  material  when 
treated  by  the  lime 
process,  gives  by  the 
sulphuric  acid  process 
at  least  75  per  cent,  of 
such  material  of  but 
slightly  inferior  quality. 
Of  this,  about  three- 
fourths  is  ready  for 
candlemaking  without 
further  treatment ;  the 
other  fourth,  when 
pressed  and  redistilled, 
yields  some  75  per 
cent,  of  its  weight  of 
stearic  acid,  and  25 
of  oleic  acid ;  ulti- 
mately, only  about  5 
parts  of  oleic  acid  per 
100  of  fat  are  obtained. 
A  considerable  pro- 
portion of  black  pitch 
(often  amounting  to 
15  per  cent,  and  up- 
wards) is  obtained  as 
bye  product,  whilst  the 
glycerol  obtainable 
from  the  acid  liquors, 
&c.,  is  much  less  in 
quantity  and  more 
costly  to  isolate  than 
that  from  the  lime 
process  ;  accordingly, 
whilst  the  larger  yield 
of  solid  fatty  acids 
renders  the  acid  method 
more  economical  from 
one  point  of  view,  it 
must  be  taken  into 
consideration,  per  con- 
tra, that  pitch  instead 
of  oleine  is  obtained  as  part  of  the  product,!  and  that  glycerol 

*  Spon's  Encyclopaedia,  p.  581,  et  seq. 

t  By  distillation  at  a  higher  temperature  the  pitch  left  on   the   first 
distillation  affords  a  certain  proportion  of  fatty  acids  of  inferior  quality. 


382 


OILS,    FATS,   WAXES,    ETC. 


is  lost,  thus  materially  diminishing  the  apparent  advant- 
ages. 

Fig.  83  illustrates  the  general  character  of  the  plant  'used  in 
the  process.*  A  is  the  tank  into  which  the  tallow,  &c.,  is  melted 
by  means  of  a  steam  jet  directed  upwards  into  the  bunghole  of 
the  cask.  B,  one  of  a  series  of  leadlined  tanks,  in  which  the  grease 
is  heated  before  treatment  with  sulphuric  acid,  so  as  to  boil  off 
water.  C,  pump  with  suitable  taps  and  connections  enabling  it  to 
pump  up  the  hot  grease  into  the  "  acidifier,"  D;  or  into  the  tank, 
H,  supplying  the  still,  I,  after  the  sulphuric  acid  has  been  washed 
out  with  water.  E,  acid  tank  supplying  acidifier.  F  F,  super- 
heaters. G  G  G  G,  washing  vats,  where  the  acidified  grease  is 
boiled  up  with  water  and  steam  to  wash  out  sulphuric  acid,  &c. 
H,  grease  tank  supplying  still,  I,  through  which  superheated 
steam  is  blown,  the  vapours  being  condensed  by  the  refrigerator, 
K,  and  copper  cooling  coils  contained  in  the  tanks,  k.  L,  scrubber 
to  condense  acrolein,  &c.  M,  pipe  leading  uncondensed  vapours, 
«fec.,  away  to  combustion  flue  for  destruction. 

Fig.  84  represents  Knab's  apparatus  for  continuous  distillation 


Fig.  84. 

by  superheated  steam.  A  is  the  distillation  vessel,  into  which 
the  fatty  acids  to  be  distilled  are  run  through  the  supply  funnel, 
C,  at  intervals  regulated  by  the  rising  and  falling  of  the  float 
valve,  D.  Superheated  steam  enters  by  the  pipe,  F  (furnished 
with  regulating  valve  and  safety  valve,  E),  and  passes  in  small 
streams  through  the  molten  fatty  acids  from  the  horizontal  coil 

*  L.  Field,  "Cantor  Lectures,1'  18S3  (Journ.  Soc.  Arts,  vol.  xxxi.,  p.  861), 


DISTILLATION    OF   FATTY   ACIDS.  383 

at  the  base.  The  vapours  pass  off  through  the  neck,  G,  to  the 
condenser ;  the  most  easily  condensed  fatty  acids  are  collected  in 
H,  and  drawn  off  from  time  to  time  through  the  cocks,  J  J, 
whilst  the  other  vapours  pass  on.  K  K  is  a  blow  off  pipe  for 
removing  residual  pitch  at  intervals,  the  supply  of  fatty  acids 
through  C  being  temporarily  shut  off.  Heat  is  applied  by  means 
of  a  bath  of  molten  lead  or  other  suitable  metal  contained  in  the 
outer  pan,  B. 

According  to  Schadler,  the  quantities  of  steam  requisite  for 
distillation  of  a  given  quantity  of  fatty  acids  at  different  tem- 
peratures are  as  follows  : — 


Temperature.  Weight  of  Steam  for  1  part  of  Fatty  Acids. 


200°  to  230C 
230°  to  260C 

290° 
325°  to  356C 


7  parts. 

3  to  4  parts. 

2  parts. 

1  part. 


When  the  distillation  temperature  does  not  exceed  240°,  the 
distilled  fatty  acids  are  almost  white  ;  at  260°  a  little  coloration 
is  manifest ;  at  290°  this  is  more  marked,  whilst  at  temperatures 
above  300°  the  distillate  is  yellow  or  brown. 

Numerous  other  forms  of  apparatus  for  effecting  distillation  by 
means  of  superheated  steam  have  been  constructed  for  particular 
purposes — e.g.,  the  purification  of  grease  from  cotton  seed  foots 
(p.  261),  of  Yorkshire  grease  (p.  277),  and  similar  substances  ; 
for  the  most  part  these  differ  from  the  above  arrangements  more  in 
details  of  construction  than  in  general  principles. 

In  Marix'  arrangement  for  the  distillation  of  free  fatty  acids 
produced  by  hydrolysis  or  otherwise  an  air  pump  is  applied,  so 
that  a  temperature  of  250°-255°  suffices  for  the  distillation  under 
diminished  pressure.  A  similar  process  has  been  patented  by  • 
Lewkowitsch  (English  patent,  5,985,  1888),  the  pressure  being 
reduced  by  10  to  13  Ibs.,  so  that  a  temperature  of  about  460°  F. 
(238°  C.)  suffices,  instead  of  about  600°  F.  (316°  C.) 

It  is  noticeable  that  when  the  products  of  distillation  of  a 
charge  of  given  material  are  collected  in  separate  fractions,  it  is 
found  that  in  some  cases  the  portions  first  passing  over  are  the 
most  fusible,  those  coming  over  later  possessing  successively 
higher  and  higher  melting  points ;  whilst  with  other  fatty  matters 
the  reverse  is  the  case.  Thus,  with  palm  oil  the  first  distillate  is 
sufficiently  solid  to  be  used  for  candlemaking  without  any  further 
treatment,  whilst  the  later  portions  are  softer,  and  must  be 
pressed  before  they  can  be  thus  employed.  With  bone  fat,  on 
the  other  hand,  the  successive  fractions  show  a  regular  increment 
in  consistency.  The  following  illustrative  figures  are  given  by 


384 


OILS,    FATS,    WAXES,    ETC. 


Payne  as  the  melting  points  of  the  fatty  acids  collected  in  seven 
different  fractions  : — 


Fraction. 

Bone  Fat. 

Palm  Oil. 

Degrees  C. 

Degrees  C. 

1 

40 

54-5 

2 

41 

52 

3 

41 

48 

4 

42 

46 

5 

45 

44 

6 

45 

41 

7 

47 

39-5 

In  almost  all  cases,  however,  the  average  melting  point  of  the 
distilled  fatty  acids  exceeds  that  of  the  crude  acids  before 
distillation. 

Bock's  Process. — In  Wilson's  process  the  hydrolysis  of  the 
glycerides  is  mainly  effected  under  the  influence  of  comparatively 
concentrated  sulphuric  acid  at  a  tolerably  high  temperature  (150° 
to  180°  C.),  and  subsequently  completed  partly  by  adding  water 
and  boiling  up  with  wet  steam,  and  partly  by  distillation  with 
superheated  steam  ;  Bock's  process  differs  therefrom  in  that  the 
hydrolysis  is  mainly  effected  by  comparatively  dilute  sulphuric 
acid,  the  action  of  which  is  facilitated  by  the  removal  of  the 
nitrogeneous  films  or  envelopes  coating  the  fatty  globules  by 
means  of  concentrated  sulphuric  acid  acting  at  a  much  lower 
temperature  than  in  Wilson's  process.  Tallow,  &c.,  is  heated  to 
115°  in  an  open  vat  *  and  well  agitated  with  from  4  to  6  per  cent, 
of  sulphuric  acid,  whereby  the  albuminous  envelopes  are  charred 
and  broken  up,  but  little  or  no  hydrolysis  effected.  Water  is 
then  added,  and  the  blackened  but  still  neutral  fat  boiled  up 
with  the  resulting  dilute  sulphuric  acid  for  some  hours  until  the 
decomposition  of  the  glycerides  is  complete,  the  degree  being 
judged  by  the  mode  of  crystallisation  of  the  fatty  acids  on  cooling 
a  sample.  When  complete,  the  acid  fluid  is  run  off  and  neutral- 
ised with  lime,  and  the  resulting  aqueous  crude  glycerine  solution 
concentrated  for  sale.  The  blackened  fatty  acids  are  then  sub- 
jected to  oxidation  by  means  of  bichromate  or  permanganate  of 
potash  and  sulphuric  or  hydrochloric  acid,  or  of  nitric  acid,  bleach- 
ing powder,  ifec.,  whereby  the  albuminous  charred  matters  are 
largely  increased  in  density  so  that  they  subside,  leaving  the 
fatty  acids  of  a  pale  brown  tint ;  these  are  then  washed  and 
crystallised,  and  subjected  to  cold  and  hot  pressure  in  the  usual 
way,  whereby  a  brown  oil  and  a  white  stearirie  are  obtained. 
The  solid  acids  obtained  are  said  to  be  whiter,  of  higher  melting 
point,  and  larger  in  quantity  than  those  obtained  from  the  same 

*  Lant  Carpenter,  British  Association  Reports,  1872,  p.  72;  vide  also 
Dinyler's  Po'ylech.  Jovrn.,  May,  1873. 


HYDROLYSIS    OF    GLYCERIDES.  385 

material  by  lime  sapoiiification,  probably  through  formation  of 
isoleic  acid,  stearolactone,  or  oxystearic  acid,  &c.  (pp.  29,  39) ; 
whilst  6  to  7  per  cent,  of  glycerine  solution  at  38°  T.  (specific 
gravity  1*19,  containing  about  70  per  cent,  of  actual  glycerol)  is 
obtainable.  The  plant  is  simple,  all  the  operations  being  carried 
out  in  one  vessel ;  and  as  only  open  steam  is  used  there  is  no 
danger  of  explosion  as  with  autoclave  processes.  If  desired,  the 
brown  oleic  acid  can  be  distilled  by  means  of  superheated  steam ; 
or  it  can  ba  converted  into  palmitic  acid  by  Radisson's  process 
(infra),  for  which  purpose  it  is  well  fitted.  100  parts  tallow 
yield  95  of  crude  fatty  acids,  reduced  to  93  by  oxidation  and 
washing,  of  which  55  to  60  parts  are  obtainable  as  candle  stearine, 
melting  at  58°  to  60°  C.  (136°  to  140°  F.) 

Hydrolysis  of  Glycerides  by  Water  Only. — In  1854  a 
patent  was  taken  out  by  Tilghmann  for  the  decomposition  of 
glycerides  by  means  of  water  under  great  pressure,  and  corre- 
spondingly high  temperature  ;  in  one  form  of  apparatus  a  mixture 
of  fat  and  water  was  forced  through  a  coil  heated  to  about 
420°  C.  (upwards  of  800°  F. ),  the  pressure  approximating  to  a  ton 
per  square  inch  (some  140  atmospheres).  Various  improvements 
were  subsequently  made  ;  but  the  practical  difficulties  attending 
the  working  of  manufacturing  operations  of  the  kind  prevented 
the  method  being  largely  adopted.  A  modification  of  the  process, 
patented  shortly  after  wards  by  Wilson  &  Payne  (No.  1,624,  1854), 
effects  the  same  result  in  a  much  simpler  way.  The  fatty 
matter  being  heated  in  a  still  to  about  300°  C.,  steam  from  a 
superheater  is  blown  through  it  by  means  of  a  rose  jet  or  false 
bottom  perforated  with  a  large  number  of  small  holes,  so  that 
numerous  jets  of  steam  rise  through  the  mass.  Hydrolysis  takes 
place,  and  the  fatty  acids  and  glycerol  formed  are  volatilised  and 
carried  over  with  the  excess  of  steam  to  the  condensers,  where 
the  free  fatty  acids  and  glycerol  in  aqueous  solution  are  obtained  ; 
the  former  condense  first,  so  that  by  using  a  series  of  condensing 
chambers,  little  but  fatty  acids  are  obtained  in  the  earlier  ones, 
whilst  chiefly  watery  glycerol  condenses  in  the  later  ones,  yielding 
a  very  pure  commercial  glycerine  by  simple  concentration  after 
separating  the  small  quantity  of  accompanying  fatty  acids. 
Fig.  85  represents  the  general  character  of  this  plant.  Steam  is 
superheated  in  the  superheater  A,  and  passes  into  the  retort,  C, 
covered  in  with  a  lid,  E  ;  the  vapours  pass  off  to  the  condensers, 
G,  for  fatty  acids,  and  F  for  glycerol  water.  If  the  temperature 
is  too  high  (above  315°),  much  loss  of  glycerol  occurs  through  the 
formation  of  acrolein. 

In  France,  the  saponification  of  fatty  matters  by  means  of 
water  alone  (without  lime,  <fcc.)  is  much  more  largely  carried 
out  than  in  Britain,  on  account  of  the  more  frequent  use  of  pure 
"  stearine "  candles,  instead  of  those  made  largely  or  wholly  of 
paraffin  wax.  Several  different  forms  of  apparatus  are  in  use  :  for 

25 


386 


OILS,    FATS,    WAXES,    ETC. 


a  description  of  some  of  these  exhibited  at  the  Paris  Exhibition, 
vide  B.  Lach,  Chem.  Zeit.,  13,  pp.  1157,  1218,  1335,  1374;  in 
abstract  Journal  tioc.  Ckem.  Ind.,  1890,  p.  82. 

Utilisation  of  Red  Oils. — In  the  manufacture  of  candle 
material  from  glycerides  a  more  or  less  considerable  propor- 
tion of  "red  oils'"  is  obtained,  the  amount  varying  with  the 


Fig.  85. 


method  of  saponificatioii  or  hydrolysis  adopted,  the  nature  of 
the  fatty  matters  used,  and  the  temperature  at  which  the  cold 
pressing  is  effected.  Commercially,  the  "  oleine  "  thus  produced 
is  considerably  less  valuable  than  the  solid  "stearine;"  whence, 
cceteris  paribus,  it  is  desirable  so  to  conduct  the  operations  as  to 
obtain  the  maximum  yield  of  solid  products  and  the  minimum  of 
liquid  ones.  In  general:  the  red  oils  thus  produced  are  utilised 
by  conversion  into  socalled  "  oil  soap/'?  by  direct  saturation  with 
soda  ley  of  appropriate  strength  (vide  Chap,  xx.)  ;  but  various 
attempts  to  employ  them  as  a  source  of  other  more  valuable 
products  have  been  made.  One  such  process,  due  to  v.  Schmidt, 
consists  in  heating  the  red  oils  with  about  10  per  cent,  of  zinc- 
chloride  to  a  temperature  of  about  185°,  whereby  conversion  into 
more  solid  substances  is  brought  about,  chiefly  by  formation  of 
isoleic  acid  and  stearolactone  (vide  p.  142).  Another  process 
(Radisson's,  vide  infra)  depends  on  the  conversion  of  oleic  into 
palmitic  acid  by  fusion  with  alkalies;  whilst  Ziirer  has  attempted* 
to  convert  oleic  into  stearic  acid  by  first  subjecting  to  the  action 
of  chlorine,  and  then  treating  the  dichloride  of  oleic  acid  formed 

*  German  Patent,  No.  62,407. 


KADISSON'S  ARTIFICIAL  PALMITIC  ACID.  387 

with  nascent  hydrogen  evolved  from  zinc  dust  (or  finely  divided 
iron  or  magnesium)  and  water  heated  under  pressure.* 

Radisson's  Artificial  Palmitic  Acid.  —  It  has  long  been 
known  that  acids  of  the  oleic  family  when  fused  with  caustic 
potash  undergo  a  peculiar  decomposition  evolving  hydrogen,  and 
breaking  up  so  as  to  form  two  acids  of  the  stearic  family,  of 
which  acetic  acid  is  generally,  if  not  invariably,  one  (p.  24)  ; 
e.g.,  oleic  acid  when  thus  treated  breaks  up,  forming  palmitic 
acid  in  accordance  with  the  equation  — 


Oleic  Acid.  Caustic  Potash. 

C18H3402     +     2KOH     -     C]6H31K02     +     C2H3K02     +     H2. 

M.  St.  Cyr  Radisson.  has  succeeded  in  carrying  out  this  reaction 
on  a  manufacturing  scale,  converting  some  3  tons  oleic  acid 
into  palmitic  acid  per  diem.  The  fusion  is  effected  in  a  covered 
iron  cylindrical  pan  or  "  cartouche  "  with  dished  base,  provided 
with  a  mechanical  agitator,  and  set  in  brickwork  some  distance 
(nearly  6  feet)  above  the  firebars  of  a  grate,  so  that  a  large 
hot  air  chamber  is  formed  underneath,  enabling  the  tempera- 
ture to  be  more  easily  regulated.  1,650  Ibs.  of  oleic  acid 
and  2,750  of  caustic  potash  ley,  specific  gravity  1-4,  are  run  in; 
when  steam  ceases  to  be  evolved,  a  manhole  in  the  cover  is 
closed,  and  the  evolved  hydrogen  passes  off  by  a  pipe  to  a  purifier 
and  gasholder  for  other  use.  The  temperature  requires  to  be 
very  nicely  adjusted,  300°  to  310°  being  the  proper  value,  whilst 
at  320°  destructive  distillation  commences  ;  to  avoid  overheating 
a  Gifford  steam  injector  is  provided  whereby  the  temperature  of 
the  interior  can  be  reduced  when  requisite.  Some  36  to  40  hours 
are  required  for  completely  working  off  a  charge,  including  filling 
the  pan  and  emptying;  the  progress  of  the  operation  is  judged 
by  sampling  and  testing  the  solidifying  point  of  the  acids 
liberated  from  the  mass  by  a  mineral  acid,  preferably  by 
Dalican's  method  (p.  74).  When  complete,  the  contents  of  the 
pan  are  run  off  through  an  outlet  pipe  into  a  tank  containing  a 
small  quantity  of  water,  and  the  whole  heated  up  by  a  steam  jet. 
The  excess  of  potash  present  then  dissolves,  forming  a  strong  ley 
(specific  gravity  about  1'14)  in  which  the  potassium  palmitate 
is  insoluble,  floating  up  as  a  soap  ;  this  is  transferred  to  a  decom- 
posing vessel  where  the  palmitic  acid  is  set  free  by  means  of 
sulphuric  acid  ;  the  acid  is  then  distilled  in  the  usual  apparatus, 
leaving  some  3  per  cent,  of  pitch,  and  furnishing  a  perfectly  white 
acid,  melting  at  50°  to  53°  C.,  burning  with  a  clear  smokeless 
flame.  About  87  per  cent,  of  white  palmitic  acid  is  obtainable 

*  De  Wilde  and  Eeychler  had  previously  shown  that  by  heating  oleic 
acid  with  a  small  quantity  of  iodine  or  bromine  under  pressure,  some  70 
per  cent,  becomes  converted  into  stearic  acid  (Bulletin  &oc.  Chem.,  Paris, 
1889,  1,  p.  295). 


388 


OILS,    FATS,    WAXES,    ETC. 


in  practice,  the  theoretical  yield  being  91  per  cent,  of  the  oleic 
acid  used.  According  to  Lant  Carpenter,  the  oleic  acid  produced 
by  Bock's  process  (supra)  is  better  adapted  to  the  purpose  than 
ordinary  red  oils  prepared  by  alkaline  saponification,  a  higher 
yield  of  palmitic  acid  being  thereby  obtained.  For  further 
details,  vide  Spon's  Encyclopaedia  of  Arts  and  Manufactures, 
p.  584. 


CHAPTER  XVII. 

MANUFACTURE   OF  CANDLES,   TAPERS,  AND 
NIGHTLIGHTS. 

SEVERAL  different  kinds  of  process  are  or  have  been  employed  in 
the  manufacture  of  candles  for  the  purpose  of  surrounding  the 
wick  with  a  more  or  less  uniform  coating  of  solid  combustible 
matter.  In  the  early  and  middle  ages,  when  wax  was  the 
material  used  by  the  more  wealthy  classes  as  illuminant,  a 
simple  mechanical  process  of  hand  manufacture  was  usually 

adopted,  a  lump  of 
wax  being  softened 
by  heat  and  kneaded 
until  sufficiently  plas- 
tic, then  applied 
round  the  wick,  and 
rolled  into  shape.  A 
similar  process  is  still 
employed,  with  the 
difference  that  the 
wax  is  applied  by 
"  pouring  "  the  just 
melted  material  over 
the  wick  so  as  to  iii- 
crust  it  with  a  layer 
of  wax ;  after  cooling, 
another  layer  is  simi- 
larly poured  over,  and 
so  on,  the  candle 

Fig>  8C  being      reversed     in 

position  from  time  to 

iime  until  the  requisite  thickness  is  attained;  the  still  somewhat 
plastic  wax  candles  are  then  rolled  into  shape,  some  half  dozen 
at  a  time,  on  a  smooth  marble  table  with  a  board  on  which  the 
workman  presses  heavily;  the  finished  candle  consequently 
exhibits  concentric  layers  of  wax,  something  like  the  rings  of  a 


DRAWING    WAX    TAPERS. 


389 


tree.  The  process  requires  considerable  skill  to  produce  a  per- 
fectly even  surface  with  truly  central  wick,  especially  in  the  case 
of  large  sized  candles  ;  to  facilitate  the  "  pouring"  or  "  basting" 
operation,  the  wicks  are  usually  hung  on  a  horizontal  wheel 
(Fig.  86)  fixed  over  the  projecting  lip  of  a  large  basin  holding 
the  melted  wax,  so  that  each  is  "basted"  in  turn.  Large  conical 
altar  candles  (cierges)  are  still  generally  made  substantially  by 
the  older  process,  the  plastic  wax  being  rolled  into  a  long  thin 
strip  or  ribbon,  which  is  then  coiled  round  the  wick  (previously 
soaked  in  melted  wax)  and  rolled  into  shape  on  the  marble  slab, 
instead  of  being  basted  on. 

In  practice  it  is  difficult  to  "mould"  wax  candles  satisfactorily 
oil  account  of  sticking  to  the  mould  and  shrinkage  during  solidi- 
fication, and  consequent  tendency  to  crack  ;  but  thin  candles  can 


Fig.  87. 

be  "drawn"  somewhat  after  the  fashion  of  wire  by  running  the 
wick  through  a  pan  of  melted  wax,  and  subsequently  making  it 
pass  through  a  drawplate  so  as  to  reduce  the  layer  of  wax  to 
uniform  thickness  (Fig.  87).  The  wick  is  usually  wound  from 
one  drum  on  to  another  ;  after  one  coating  is  applied  it  is  wound 
back  again,  this  time  passing  through  a  somewhat  wider  draw- 
hole,  so  as  to  give  an  increased  thickness  of  wax ;  as  a  rule, 
however,  neat  tapers  of  more  than  about  half  an  inch  diameter 
cannot  be  conveniently  made  thus,  as  the  tendency  to  crack 
becomes  too  great  when  the  diameter  increases  beyond  this 
point.  In  whatever  way  the  wick  is  coated,  whether  by  "  rolling," 
"  pouring,"  or  "  drawing,"  the  candles  are  ultimately  finished  by 
cutting  off  the  butt  ends  clean  with  a  sharp  knife  (Fig.  88),  and 
trimming  the  other  ends  to  conical  tips.  When  tinted  wax 
candles  are  requisite  usually  only  the  last  batches  basted  on  are 


390 


OILS,    FATS,    WAXES,    ETC. 


coloured,  as  the  tinting-  materials  are  generally  apt  to  clog  the 
wick,  especially  if  solid ;  for  white  candles  airbleached  wax 
(p.  268)  is  employed,  wTax  blanched  by  chemicals  (especially 
chlorine)  being-  unsuitable  (p.  267). 


Fig.  88. 

Dip  Candles. — In  the  preparation  of  rough  candles  for  house- 
hold use  in  mediaeval  times  and  even  still  more  recently,*  the 
wicks  used  were  generally  rushes  (Juncus  conglomeratus)  skilfully 


Fig.  89. 

peeled  so  as  to  leave  the  pith  supported  by  one  thin  rib  of  green 
rind,  whence  the  familiar  term  "rushlight."  These  were  soaked 
(after  drying)  in  melted  tallow  or  kitchen  grease,  held  up  to 

*  Gilbert  White,  "Natural  History  of  Selborne"  1789. 


EDINBURGH    WHEEL. 


391 


cool,  and  then  dipped  again  carefully  into  the  just  melted  grease 
and  quickly  withdrawn,  so  that  the  film  of  adherent  tallow 
solidified  before  it  had  time  to  run  down  ;  for  which  purpose 
it  was  imperative  that  the  grease  should  not  be  overheated. 
The  dipping  was  then  repeated  at  intervals  until  the  coating  of 
tallow  was  sufficiently  thick.  By  and  bye  when  tallow  candle- 
making  became  a  trade  of  itself  this  method  of  manipulation  was. 
adopted  on  a  larger  scale  with  appropriate  modifications ;  linen 
or  cotton  wicks  supplanted  rush  pith,  whilst  the  dipping  was 
effected  by  fixing  a  number  of  wicks  (previously  soaked  in  tallow) 
on  hooks  driven  side  by  side  a  little  way  apart  into  the  bottom 
of  a  piece  of  board  or  wooden  lattice  frame,  so  that  by  lifting  the 
board  by  means  of  a  knob  or  handle  on  the  upper  side,  all  the 
wicks  attached  could  be  simultaneously  dipped  and  withdrawn. 
To  facilitate  the  dipping,  the  board  with  dependent  candles  was 
attached  to  a  rope  passing  over  a  pulley  (Fig.  89) ;  each  frame  of 
candles  when  dipped  being  unhooked  from  the  rope  and  suspended 
from  the  periphery  of  a  horizontal  wheel  so  as  to  hang  up  and 
harden  ;  by  dipping  in  regular  succession  each  one  of  a  number 
of  frames  thus  suspended,  each  batch  of  candles  became  suffi- 
ciently cooled  and  "  set "  to  be  ready  for  another  dip  by  the  time 
its  turn  came ;  the  wheel  thus  slowly  revolved,  making  one 
revolution  for  each  dipping  of  the  whole  series  of  frames  suspended 
therefrom.  By  attaching  suitable  weights  to  the  end  of  the  cord 
as  counterpoise  the  time  is  easily  ascertained  when  the  candles 
have  been  dipped  sufficiently  often  to  be  of  the  right  weight. 

To  avoid  the  trouble  of  unhooking  each  frame  and  hanging  it 
up  from  the  wheel  a  series 
of  separate  radiating  bars 
have  been  substituted  for 
the  complete  wheel,  each 
bar  being  capable  of  oscil- 
lating in  a  vertical  plane 
working  011  a  pin  in  a 
slot  in  the  vertical  axis. 
Fig.  90  represents  a  form 
of  "Edinburgh  wheel" 
of  this  description  ;  each 
bar,  B  B,  carries  two 
dipping  frames,  one  at 
each  end,  the  second 
serving  as  counterpoise 
to  the  first ;  each  frame 
is  successively  pulled 
down  and  dipped  in  the 
tallow  cauldron  and  then 


Fig.  90. 


raised  again,  the  wheel  being  made  to  revolve  partially  so  as  to 
bring  the  next  succeeding  frame  over  the  cauldron.     Various 


392 


OILS,    FATS,    WAXES,    ETC. 


subsidiary  arrangements  are  sometimes  applied  for  the  purpose 
of  ensuring  horizontality  of  the  radiating  bars  when  raised  after 
dipping  even  though  the  newly  dipped  end  may  be  a  little 
heavier  than  its  counterpoise. 

The  wicks  may  be  suspended  from  the  hooks  by  means  of  a 
loop  of  cotton  thread  tied  to  them ;  but  a  more  convenient  plan 
is  to  double  the  wick,  stringing  the  series  over  a  rod  as  indicated 
in  Fig.  91.  The  rod  with  the  dependent  wicks  is  then  dipped 
by  hand  into  a  trough  of  melted  tallow  and  hung  up  on  a  rack 
or  otherwise  supported  until  the  tallow  is  sufficiently  set  to 
permit  of  another  dipping  ;  or  a  series  of  rods  are  attached  side  by 
side  to  a  frame  supported  by  cords  and  attached  to  an  hdinburgh 
wheel,  ifcc.  In  order  to  impregnate  the  wicks  with  tallow  in  the 
first  instance  and  to  get  them  all  of  the  right  length,  the  wick  is 


=$F$F$=^^ 


Fig.  91. 

unwound  from  a  bobbin,  and  wound  round  a  square  frame  of 
suitable  size  so  as  to  form  a  sort  of  loose  covering ;  this  is  then 
dipped  bodily  in  hot  tallow  to  within  an  inch  or  so  of  the  top 
of  the  frame,  so  as  to  fill  up  all  the  pores  in  the  immersed 
portion  of  the  wicking :  the  entire  row  of  strands  at  the  bottom 
of  the  frame  is  then  cut  through  wyith  a  knife,  and  the  different 
doubled  wicks  separated,  and  strung  on  the  rods  as  indicated. 

Another  mode  of  proceeding,  formerly  much  used  in  the  larger 
dipping  establishments,  is  to  have  the  cauldron  of  melted  tallow 
movable,  so  as  to  pass  in  succession  beneath  each  one  of  a  series 
of  frames.  Fig.  92  represents  the  section  of  an  arrangement  of 
the  kind  :  the  two  frames,  D  D,  are  connected  by  a  cord  passing 
over  pulleys  supported  by  a  beam  arid  posts,  so  that  one  counter- 
poises the  other ;  by  pulling  the  cords,  E  E,  the  one  or  the  other 
can  be  made  to  descend.  A  number  of  these  pairs  of  frames  are 
arranged  side  by  side  (Fig.  93)  the  cauldron  of  tallow  (kept  fluid 
by  means  of  a  brazier)  running  on  a  railway  down  one  side  of  the 
row  and  up  the  other,  so  that  each  one  of  the  frames  is  dipped  in 
regular  rotation.  A  sort  of  mechanical  wiper  is  conveniently 
connected  with  the  cauldron,  so  that  by  moving  a  lever  after  the 
candles  have  emerged  from  the  molten  tallow  the  drops  of  melted 
grease  that  run  down  to  the  bottoms  are  removed.  When  well- 
shaped  candles  are  required,  the  irregularities  may  be  smoothed 
down  by  pulling  each  candle  in  succession  by  hand  through  a 
series  of  holes  in  a  drawplate  (graded  in  diameter,  the  smallest 


DIP    CANDLES. 


393 


being  the  size  ultimately  required)  so  as  to  strip  off  a  portion  of 
the  outer  coating,  leaving  the  remainder  fairly  cylindrical. 

A  peculiar  modification  of  the  dipping  process  is  sometimes 
practised  :  the  wicks  are  dipped  in  hot  melted  tallow  as  usual  to 
fill  up  pores;  instead  of  applying  the  outer  coatings  by  successive 
dippings  of  the  treated  wicks,  thin  steel  rods  are  dipped  in  the 
tallow ;  when  the  candles  are  of  the  requisite  thickness  they  are 
cooled  completely,  and  the  steel  cores  extracted ;  the  wicks  are 
then  passed  through  instead,  and  fastened  in  position  by  a  few 


L_J 


Fig.  92. 


Fig.  93. 


drops  of  melted  tallow.  A  similar  device  is  also  employed  in  the 
manufacture  of  certain  kinds  of  night  lights  (infra),  except  that 
the  wickless  hollow  candles  are  made  by  casting  instead  of 
dipping. 

At  the  present  day,  although  the  manufacture  of  dip  candles 
made  of  unsaponified  tallow  is  by  no  means  extinct  (there  being 
still  some  considerable  demand,  especially  in  country  districts), 
the  quantity  manufactured  is  much  less  than  that  of  "  moulded" 
candles,  mostly  prepared  from  solid  fatty  acids  ( socalled 
"stearine")  and  paraffin  wax,  but  sometimes  from  unsaponified 


394  OILS,    FATS,    WAXES,    ETC. 

tallow  or  mixtures  containing  both  free  fatty  acids  and  solid 
unsaponified  glycerides  (composites).  Tallow  candles,  when 
blown  out,  generally  emit  an  acrid  vapour,  due  to  the  decomposi- 
tion of  the  glyceride  by  the  heat  of  the  smouldering  wick,  with 
formation  of  acroleiii ;  this  circumstance,  together  with  their 
comparative  softness  inducing  "guttering,"  the  necessity  for 
"  snuffing,"  and  the  tendency  to  emit  smoke  and  give  a  less 
clear  brilliant  light  than  stearine  and  paraffin  candles,  has  caused 
them  gradually  to  fall  comparatively  into  disuse,  especially 
amongst  dwellers  in  towns. 

Wicks. — The  nature  of  the  wick  employed  in  a  candle  very 
greatly  affects  the  way  in  which  it  burns,  and  consequently  the 
light  emitted.  In  the  old  fashioned  tallow  dip  candle,  thick 
twisted  cotton  wicks  are  still  used ;  these  do  not  thoroughly 
consume  away,  and  consequently  "  snuffers "  are  requisite  in 
order  to  remove  the  charred  smouldering  cotton,  otherwise  much 
less  light  is  given  out,  and  a  smoky  flame  produced.  By  various 
mechanical  devices,  attempts  have  been  made  to  give  to  such 
twisted  wicks  a  tendency  to  bend  outwards  in  the  flame,  so  as  to 
come  in  contact  with  the  air  and  consume  spontaneously  ;  others 
have  sought  to  attain  the  same  end  by  incorporating  a  thin  wire 
with  the  cotton  strands.  Palmer's  "  metallic  wick "  was  an 
analogous  device,  where  a  thread  impregnated  with  powdered 
bismuth  was  bound  up  with  a  number  of  others  of  ordinary 
fibres  by  winding  one  round  the  bunch  ;  when  burnt,  the 
bismuth  formed  a  minute  globule  at  the  end  of  the  wick,  the 
weight  of  which  tended  to  draw  the  wick  outwards  ;  so  that  the 
carbonised  cotton  was  burnt  away,  and  the  bismuth  volatilised, 
or  was  otherwise  dissipated  by  combustion.  De  Milly  attempted 
to  gain  the  same  result  by  impregnating  the  wicks  with  boracic 
and  phosphoric  acids,  &c.,  so  as  to  form  a  globule  of  fused 
mineral  matter.  All  such  devices,  however,  have  been  super- 
seded for  the  better  classes  of  candle  by  the  use  of  flat  plaited  or 
"  braided "  wicks  (first  introduced  by  Cambaceres),  where  the 
mode  of  construction  imparts  a  natural  tendency  to  bend 
outwards.  The  precise  mode  of  plaiting  adopted  considerably 
modifies  the  way  in  which  the  wick  burns,  one  kind  of  braiding 
being  better  suited  than  another  for  certain  kinds  of  combustible 
matter ;  thus,  paraffin  candles  require  a  wick  more  tightly 
braided  than  is  requisite  for  stearine  candles,  whilst  looser 
wicks  are  used  for  wax  and  sperm  candles.  As  a  rule,  the 
plaiting  of  the  wicks  is  not  carried  out  in  the  candle  factory,  but 
by  spinners  making  a  speciality  of  this  particular  line,  and 
delivering  the  braids  in  hanks  of  convenient  size  ;  the  machines 
used  much  resemble  those  employed  in  the  manufacture  of 
ordinary  braids. 

Wick  Pickling. — Before  conversion  into  candles,  the  wicks 
are  soaked  or  "pickled"  in  a  suitable  saline  solution  for  some 


MOULDED    CANDLES.  395 

hours ;  they  are  then  drained  and  finally  wrung  out  by  means  of  a 
rapidly  rotating  centrifugal  machine  so  as  expel  almost  the  whole 
of  the  fluid  without  twisting  the  threads  in  any  way,  and  finally 
hung  up  to  dry  in  a  room  heated  by  steam  pipes.  The  object  of 
the  pickling  is,  on  the  one  hand,  to  counteract  the  accumulation 
of  mineral  matter  or  "ash"  in  the  wick  as  it  burns,  and  on  the 
other,  to  prevent  the  too  rapid  burning  away  of  the  wick  fibres 
before  the  due  quantity  of  melted  fatty  matter  has  passed  along 
them  and  been  consumed  in  the  flame.  The  choice  of  the  parti- 
cular solutions  employed  and  their  strengths  is  usually  regarded 
as  a  trade  secret,  each  manufacturer  having  his  own  views  on  the 
subject  to  which  experience  has  guided  him  ;  solutions  varying 
from  1  to  5  per  cent,  of  saline  matter  in  strength  have  been 
recommended,  such  as  borax  (alone,  or  acidulated 'with  a  minute 
quantity  of  sulphuric  acid),  salammoniac,  saltpetre,  phosphate  of 
ammonium,  or  mixtures  of  such  salts  ;  although  only  very  minute 
quantities  of  saline  matters  ultimately  remain  in  the  dried  wicks, 
yet  the  effect  thereby  produced  on  the  way  in  which  the  candle 
burns  is  often  very  marked. 

MOULDED  CANDLES. 

The  art  of  moulding  candles,  instead  of  dipping  them,  is  due 
to  the  Sieur  de  Brez  in  the  fifteenth  century;  but  excepting  for 
the  employment  of  this  method  in  the  manufacture  of  spermaceti 
candles  in  the  latter  part  of  the  last  century,  but  little  advance 
was  made  in  this  direction  until  the  introduction  of  "  stearine  " 
(solid  free  fatty  acids)  as  candle  material  instead  of  tallow,  and 
the  subsequent  employment  of  paraffin  wax  for  the  same  purposes 
a  little  after  the  middle  of  the  present  century.  The  earlier 
moulding  machines  were  socalled  "  hand  frames  "  (still  in  use  for 
small  operations  and  special  sizes  for  which  only  a  small  demand 
exists)  containing  a  series  of  pewter  moulds  with  removable- 
mouthpieces,  Fig.  94,  depending  downwards  from  a  shallow 
trough,  Fig.  95,  the  top  end  being  lowest  and  the  butt  end 
uppermost.  By  means  of  a  wire  with  a  hook  at  the  end  the 
wick  was  hooked  through  a  narrow  orifice  at  the  conical  lowest 
end  of  the  mould  and  brought  upwards,  and  finally  fixed  to  a 
wire  hook,  n,  by  means  of  a  knot  on  the  wick,  or  preferably  a 
little  loop  of  cotton  thread  tied  to  the  wick ;  so  that  by  gently 
pulling  the  wick  downwards  at  the  bottom  and  fixing  it  with 
a  peg,  it  was  stretched  in  the  axis  of  the  cylindrical  mould 
(Fig.  96) ;  or  instead  of  a  removable  mouthpiece  carrying  a  hook 
like  n,  a  short  piece  of  wire  was  passed  through  the  loop  and 
allowed  to  rest  in  a  couple  of  shallow  notches  opposite  to  one 
another  in  the  upper  rim  of  the  mould,  so  that  the  wick  depended 
axial ly  therefrom.  Figs.  97  arid  98  represent  an  improved 
modification  of  this  arrangement,  where,  instead  of  having  a 


,396 


OILS,    FATS,    WAXES,    ETC. 


VJ 
Fig.  94. 


Y 

Fig.  96. 


Fig.  93. 


Fig.  97. 


Fig.  98. 


HAND    MOULDING    FRAMES. 


397 


separate  wire  for  each  candle,  a  whole  row  of  wicks  is  simul- 
taneously supported  by  a  single  rod,  D  D,  which  is  with- 
drawn when  the  candles  are  extricated  from  the  moulds  after 
cooling.  The  use  of  this  rod  generally  leaves  a  corresponding 
mark  or  groove  at  the  base  of  the  finished  candle,  whereby  a 
hand  made  article  can  be 
readily  recognised.  The 
moulds  being  somewhat 
warmed  so  as  not  to  chill 
the  candle  material  too 
quickly,  the  molten  sub- 
stance is  poured  into  the 
trough  so  as  to  fill  all  the 
moulds,  and  also  part  of 
the  trough  to  allow  for 
shrinkage ;  the  whole  is 
then  set  by  to  cool,  and 
when  the  candles  are  suf- 
ficiently set,  the  contents 
of  the  trough  are  scooped 
out  with  a  trowel.  Pre- 
ferably, the  frame  carry- 
ing the  series  of  moulds  is 
immersed  in  a  water  tank 
so  as  to  facilitate  the  chill- 
ing, the  temperature  of  the 
water  varying  with  the 
nature  of  the  material 
used  and  the  dimensions 
of  the  candles  moulded ;  it 
being  usually  necessary 
that  the  solidification 
should  go  on  at  a  par- 
ticular rate,  otherwise  a 
crystalline  structure  may 
be  developed  by  too  slow 
cooling,  injuring  the  ap- 
pearance of  the  candle,  or 
cracking  may  occur  with 
too  rapid  chilling.  When 
the  candles  are  completely 
set,  the  frame  is  removed 
from  the  water,  and  the  Fig.  99. 

candles  extricated  by  re- 
moving the  pegs  and  inverting  the  frame,  when  they  mostly 
fall  out  of  themselves  owing  to  the  moulds  being  slightly  conical; 
if  sticking  occur,  gently  tapping  the  mould  generally  suffices  to 
dislodge  the  candle.   Including  "threading" — i.e., setting  the  wicks 


.398 


OILS,    FATS,    WAXES,    ETC. 


in  position  by  hand  (by  passing  it  through  the  lower  orifice  and 
pulling  it  upwards  by  means  of  a  wire) — filling,  and  emptying, 
hand  frames  can  only  be  worked  off  about  once  in  an  hour,  or 
somewhat  less  frequently.  In  the  later  "  continuous "  candle 
moulding  machines,  three  times  this  speed  is  attained,  much  time 
being  saved  by  a  device  whereby  the  wick  is  passed  continuously 
at  stated  intervals  through  the  mould,  a  candle  being  cast  at  each 
period,  and  when  set,  lifted  upwards  so  as  to  draw  the  wick  into 
position  for  the  next  moulding,  so  that  a  string  of  candles,  one 
after  the  other,  is  cast  around  each  wick. 

Fig.  99  represents  Royan's  form  of  continuous  wick  moulding 
machine  as  used  in  Germany  (Schadler) ;  as  each  batch  of  candles 
is  cast  and  becomes  sufficiently  hard,  they  are  lifted  upwards  out 


Fig.  100. 

of  the  moulds  by  means  of  a  rack  and  pinion  which  elevates  a 
platform  to  the  under  side  of  which  the  wicks  are  fastened  by  a 
series  of  clips  ;  in  this  way  the  wicks  are  always  kept  gently 
stretched  along  the  axes  of  the  moulds  ;  several  successive  tiers 
of  candles  are  thus  moulded  without  altering  the  attachments. 
When  the  platform  reaches  its  highest  elevation  the  wicks  are 
severed  below  the  lowest  tier,  and  the  strings  of  candles  removed 
from  the  clips  that  support  them ;  the  platform  is  then  lowered 
and  the  wick  ends  affixed  to  the  clips,  and  the  operations  com- 
menced afresh. 

Fig.  100  represents  "  Camp's  moulding  wheel,"  a  combination  of 
the  principle  of  the  "  Edinburgh  wheel ''  used  for  dipping  candles 
with  this  "continuous"  moulding  action;  this  arrangement  has  been 
.somewhat  extensively  used  in  America  (Christian!).  A  revolving 


CONTINUOUS    MOULDING    MACHINES. 


399 


horizontal  wheel,  B,  is  supported  by  iron  rods,  O  O  O,  and  turns 
on  a  pivot,  C,  attached  to  the  roof.  A  series  of  moulding  frames, 
A  A  A,  are  supported  by  the  wheel,  regularly  arranged  radiating 
from  the  centre;  the  troughs,  b  b,  b  b,  surrounding  these  can  be 
filled  with  water  heated  to  any  required  temperature  by  means 
of  steam  pipes,  or  if  need  be  cooled  with  ice.  Just  below  the 
tips  of  the  moulds  are  the  rows  of  bobbins  of  wick,  the  ends  of 
which,  to  begin  with,  are  drawn  upwards  by  hand  and  adjusted 
in  the  axes  of  the  moulds.  When  all  the  moulds  are  ready  the 
discharge  valve,  P,  of  a  tank  of  melted  candle  material,  M,  is 
opened  so  as  to  fill  one  of  the  mould  frames  in  position  under- 
neath ;  the  wheel  is  then  pushed  round  until  the  next  mould 
frame  is  in  position  under  the  spout,  when  this  is  similarly  filled  ; 
and  so  on  with  all  in  turn.  By  the  time  the  last  frame  is  filled 
the  first  will  have  cooled  sufficiently  to  enable  the  candles  to  be 
cautiously  withdrawn  and  laid  over  in  grooves  cut  for  their 
support  in  the  ledges  of  the  frame ;  as  this  is  done  the  wricks 
are  drawn  upwards,  so  that  the  moulds  are  threaded  ready  for 
the  next  filling.  The  mould  frame  thus  emptied  is  refilled  with 
melted  candle  material ;  and  similarly  with  the  next,  so  that  the 
wheel  is  revolved  a  second  time,  each  mould  frame  being  filled 
in  succession  as  before  ;  when  all  the  frames  are  filled  the  candles- 
lying  over  in  the  grooves  (by  this  time  perfectly 
hard  and  solid)  are  cut  off  and  removed,  and  these 
now  filling  the  moulds  are  pulled  upwards  and 
made  to  take  their  place. 

The  moulding  machines  in  use  at  the  present 
day  in  the  larger  factories  are  mostly  constructed 
on  the  "piston"  principle,  whereby  the  candles 
when  sufficiently  set  are  mechanically  expelled 
from  the  moulds  by  means  of  a  series  of  pistons 
rising  up  therein  and  lifting  the  candles  out.  Fig. 
101  represents  the  general  mode  of  action,  identical 
in  principle  with  that  of  an  ordinary  "  lifting 
pump "  without  the  valve,  excepting  that  the 
piston-rod  is  below  instead  of  above ;  the  piston  is 
hollowed  conically  so  as  to  form  the  mould  of  the 
candle  tip  ;  the  wick  passes  upwards  through  the 
tubular  piston-rod.  A  series  of  moulds  is  arranged 
in  a  convenient  frame  or  trough  into  which  water 
can  be  run  heated  by  means  of  steam,  or  artificially 
cooled  as  may  be  requisite  according  to  the  tem- 
perature at  which  the  moulds  are  to  be  kept,  which  Fig.  101. 
varies  with  the  nature  of  the  candle  material. 

Fig.  102  represents  a  moulding  machine  containing  two  such 
troughs  arranged  parallel,  each  containing  a  double  row  of 
moulds  set  in  a  suitable  frame  with  the  piston-rods  all  depressed; 
this  is  effected  by  connecting  them  all  to  a  horizontal  shelf 


400 


OILS,    FATS,    WAXES,    ETC. 


(driving  plate)  capable  of  being  raised  or  lowered  at  will  by 
means  of  a  handle  working  a  pinion  gearing  into  a  rack  ;  as  the 
shelf  is  raised  the  four  rows  of  candles  are  simultaneously  lifted 
upward  by  the  ascent  of  the  pistons.  As  they  rise  they  pass 
through  four  series  of  grooved  jaws  or  ':  nippers"  slightly  open  ; 
at  the  summit  of  the  elevation  these  jaws  close,  gently  grasping 
iind  supporting  the  candles,  the  grooves  being  lined  with  felt  or 
preferably  india  rubber.  The  handle  is  then  turned  the  reverse 
way  so  as  to  depress  the  pistons  to  the  lower  ends  of  the  moulds  ; 
the  wicks  attached  at  the  upper  ends  to  the  rows  of  candles 
supported  by  the  nippers  are  consequently  stretched  in  the  axes 
of  the  moulds,  having  been  unwound  from  the  bobbins  beneath 
during  the  ascent  of  the  candles. 


Fig.  102. 

To  commence  operations,  each  wick  is  hooked  up  by  means  of 
a  wire  through  the  hollow  piston-rod  and  fixed  in  the  axis  of  the 
mould,  as  in  the  hand  frame  ;  melted  candle  material  is  then 
poured  into  the  moulds,  and  when  set  the  candles  are  lifted  out 
(by  raising  the  pistons)  and  held  by  the  nippers,  the  wicks  being 
thus  pulled  upwards  into  position  for  the  next  casting  ;  the 


MOULDED    CANDLES.  401 

pistons  are  then  depressed,  sliding  over  the  wicks  as  they 
descend ;  the  temperature  of  the  water  trough  is  adjusted  if 
requisite,  and  a  new  batch  of  candles  cast  by  pouring  in  more 
melted  candle  material.  When  this  has  set  sufficiently  to  keep 
the  wick  in  its  central  position  without  extraneous  aid,  the  upper 
rows  of  candles  held  by  the  nippers  are  detached  by  cutting 
through  the  wicks ;  the  nippers  holding  the  candles  are  then 
opened  and  the  candles  extracted,  or,  preferably,  are  lifted  off 
(being  detachable)  and  emptied  on  to  a  table,  &c.  The  nippers 
are  then  replaced  and  the  process  repeated  until  the  wick  bobbins 
are  exhausted. 

The  lengths  of  the  candles  thus  moulded  in  a  given  set  of 
cylinders  can  be  regulated  at  will  by  simply  raising  the  driving 
plate  by  means  of  set  screws,  so  as  to  shorten  the  distance 
between  each  piston  and  the  top  of  the  corresponding  mould,  and 
thus  form  a  shorter  candle  ;  or  vice  versd.  When  the  butt  ends 
of  the  candles  are  required  to  be  conical  (so  as  to  fit  into  any 
sized  stick),  a  special  kind  of  cutting  machine  is  employed  to 
shave  down  the  ends.  If  the  cone  is  to  be  of  greater  diameter  at 
its  base  than  the  rest  of  the  candle,  a  special  modification  of  the 
mould  is  employed  (infra}. 

The  chief  skill  required  in  working  the  candle  moulding 
machine  lies  in  properly  regulating  the  temperature,  the  modus 
operandi  varying  in  this  respect  with  the  material.  With  pure 
stearine  (i.e.,  solid  fatty  acids  with  just  enough  paraffin  wax, 
beeswax,  or  vegetable  wax,  or  other  similar  material  to  u  break 
the  grain,"  and  prevent  or  diminish  crystallinity),  the  moulds 
are  kept  at  a  temperature  slightly  below  the  setting  point  of  the 
candle  material,  which  is  poured  in  on  the  point  of  congealing, 
well  stirred  so  as  to  form  a  gruel-like  mass.  The  workman 
generally  judges  the  temperature  by  simply  putting  his  hand  into 
the  water  trough  surrounding  the  moulds,  cooling  it  by  running 
in  a  little  cold  water  if  requisite,  or  vice  versd.  With  paraffin 
wax,  on  the  other  hand,  the  moulds  must  be  heated  by  hot  water 
or  steam  well  above  the  melting  point  of  the  wax  (usually  up  to 
80°  to  85°,  or  about  170°  F.),  whilst  the  wax  also  should  be  hotter 
than  its  fusing  point;  when  the  moulds  are  filled,  the  surrounding 
hot  water  is  run  off  and  cold  water  run  in  instead,  whereby  the 
material  is  quickly  chilled,  and  the  peculiar  translucency  and 
lustre  desired  is  attained.  In  certain  cases  this  effect  is 
heightened  by  alternately  admitting  hot  and  cold  water  into 
the  water  box,  the  precise  mode  of  operating  varying  somewhat 
according  as  paraffin  scale  of  relatively  low  melting  point  is  used, 
or  harder  paraffin  (cerasin,  ozokerite,  &c.)  of  higher  melting  point, 
witli  or  without  the  addition  of  a  few  per  cents,  of  stearic  acid, 
either  for  the  purpose  of  serving  as  vehicle  for  colour  (p.  405),  or 
to  prevent  the  tendency  to  soften  and  bend  often  shown  by  pure 
paraffin  candles,  even  at  temperatures  considerably  below  the 

26 


402 


OILS,    FATS,    WAXES,    ETC. 


fusing  point.  In  some  cases,  where  mixed  materials  are  used 
with  stearine  in  larger  quantity,  intermediate  temperatures  are 
employed  for  the  water  box.  In  Britain,  paraffin  candles  have 
largely  driven  fatty  acid  candles  out  of  the  market  on  account  of 
their  greater  cheapness,  but  this  is  not  so  much  the  case  on  the 
Continent. 

Moulded  tallow  candles  were  formerly  somewhat  largely 
employed,  but  latterly  have  mostly  gone  out  of  use  along  with 
dips  on  account  of  the  objections  to  glycerides  as  combustible 
matter  (p.  394).  The  same  remark  also  largely  applies  to 
"  composites,"  or  mixtures  of  free  fatty  acids  and  glycerides, 
except  for  night  lights  (p.  406). 

Spermaceti  candles  are  usually  moulded  in  much  the  same 
way  as  paraffin  wax  candles,  the  material  being  heated  above  its 
melting  point  and  run  into  hot  moulds,  which  are  then  rapidly 
chilled  by  means  of  cold  water.  During  the  latter  part  of  the 
last  century  and  the  earlier  portion  of  the  present  one  they  were 
in  some  considerable  amount  of  use  by  the  wealthier  classes  ; 
but  like  wax  candles,  their  use  is  but  small  nowadays  as  com- 
pared with  candles  of  "stearine"  and  paraffin  wax.  With 
properly  adjusted  wicks  they  burn  with  considerable  regularity 
and  brightness,  and  are  accordingly  selected  as  the  practical 
standard  for  photometric  observations  ;  a  "  standard  candle ;' 
being  one  burning  120  grains  of  spermaceti  per  hour. 

For  certain  special  forms  of  candle  particular  modifications  of 
the  moulding  machine  are  requisite  ;  thus  stearine 
candles,  especially  on  the  Continent,  are  often  cast 
with  longitudinal  internal  spaces  or  tubes,  which 
tend  to  prevent  "  guttering "  whilst  burning. 
Spiral  exteriors  are  also  much  in  favour;  formerly 
these  were  made  by  lathing  cylindrical  candles 
cast  in  the  ordinary  moulds  ;  but  in  the  more 
recent  machines  the  pistons  are  made  to  ascend 
by  a  screw  motion,  the  moulds  themselves  being 
correspondingly  grooved,  so  that  the  candles  are 
screwed  out  of  the  moulds.  For  "  self-fitting " 
butt  ends  (Fig.  103),  where  the  thickest  portion 
of  the  conical  part  is  of  greater  diameter  than  the 
rest  of  the  candle,  the  frame  above  described 
requires  modification.  Fig.  104  represents  a 
machine  for  moulding  self-fitting  butt  end  candles, 
constructed  by  E.  Cowles,  of  Hounslow,  where  the 
butts  are  shaped  by  a  separate  series  of  moulds 
fitting  on  the  top  of  the  cylindrical  moulds,  and  ultimately  lifted 
off  from  the  conical  candle  ends  by  means  of  the  chain,  the  candles 
being  then  raised  by  the  piston  and  held  in  removable  nipping 
frames  in  the  usual  way.  This  arrangement  does  not  permit  of  the 
wick  being  run  continuously ;  after  each  batch  of  candles  is  cast 


Fi<r.  103. 


SELF-PITTING    BUTT   ENDS. 


403 


404 


OILS,    FATS,    WAXES,    ETC. 


the  wicks  must  bo  severed,  and  after  removal  of  the  nipping 
frames  and  candles  the  butt  mould  lowered  into  position  ;  each 
wick  is  then  hooked  up  through  its  appropriate  butt  mould  and 
clamped  centrally  in  the  axis  of  the  mould  so  as  to  be  ready  for 
the  next  casting.  This  involves  much  trouble  and  delay,  besides 
causing  the  waste  of  a  short  length  of  wick  at  each  candle  end. 


These  objections  are  obviated  by  making  the  butt  end  moulds 
in  two  halves,  separable  from  one  another  at  will,  so  as  to  permit 
of  the  candles  rising  upwards  when  the  half-moulds  are  apart,  but 
tightly  closing  together  and  fitting  accurately  on  the  tops  of  the 
piston  moulds  when  required  ;  the  opening  and  shutting  is  simply 
effected  by  the  motion  to  or  fro  of  a  separate  handle.  When  the 
moulds  are  closed,  the  melted  candle  material  is  poured  in ;  after 


TINTED    CANDLES. 


405 


setting,  this  handle  is  moved  back  so  as  to  open  the  butt  moulds  ; 
the  main  handle  actuating  the  pistons  is  then  moved  so  as  to 
raise  the  candles  into  the  nipping  frame ;  the  pistons  are  then 
lowered,  the  butt  moulds  closed,  and  a  new  casting  proceeded 
with. 

Fig.  105  represents  a  "turnover"  machine,  swinging  on  trun- 
nions, so  that  when  a  hard  candle  material  has  been  run  into 
the  moulds  and  has  partly  solidified  round  the  sides,  the  machine 
can  be  tipped  over  so  as  to  allow  the  still  liquid  portion  of  the 
material  in  the  centre  of  the  moulds  to  run  out,  thus  leaving 
hollow  candles  which  are  then  filled  in  with  softer  material; 
candles  of  comparatively  easily  fusible  substance  can  thus  be 
prepared  with  an  outer  casing  of  less  fusible  material  which  pre- 
vents the  guttering  that  would  otherwise  occur. 

Stearine  candles  are  comparatively  seldom  tinted,  being  gener- 


Fig.  106.' 

ally  burnt  uncoloured  ;  sometimes,  however,  they  are  tinted 
yellowish  with  gamboge,  &c.  For  tinted  paraffin  candles,  how- 
ever, a  considerable  demand  exists.  Formerly  the  candle 
material  was  coloured  by  incorporating  a  small  quantity  of  very 
finely  ground  pigment ;  but  this  is  now  never  done  if  it  can  be 
avoided,  as  the  wick  almost  invariably  becomes  clogged  after 
burning  a  short  time,  so  that  a  smoky  less  luminous  flame 
results.  Coaltar  dyestutf's  are  generally  preferred,  as  far  as  pos- 
sible free  from  fixed  mineral  constituents ;  in  many  cases  these 
will  not  dissolve  in  pure  paraffin  wax;  but  by  dissolving  them 
in  fused  stearic  acid,  and  incorporating  a  little  of  the  solution 
with  the  melted  paraffin,  the  latter  can  usually  be  readily  tinted 
any  required  depth  of  shade. 

In  the  case  of  stearine  and  wax  candles,  and  sometimes  with 
other  varieties  also,  an  extra  degree  of  gloss  and  polish  is  some- 


406  OILS,    FATS,    WAXES,    ETC. 

times  given  to  the  surface  by  rubbing  and  rolling  them  by  hand 
or  between  cloth-covered  rollers,  &c.  ;  several  machines  have 
been  constructed  for  this  purpose.  Fig.  106  indicates  a  simple 
arrangement  where  the  candles  are  gradually  passed  out  of  the 
tray,  A  (by  means  of  the  grooved  roller,  B)  on  to  the  endless 
cloth,  E  D  E  D,  and  rolled  between  the  cloth-covered  rollers, 
G  G  G,  and  the  cloth  ;  the  latter  moves  in  such  a  direction  as  to 
carry  the  candles  forward  towards  the  tray,  H,  whilst  the  rollers, 
G  G  G,  revolve  in  a  contrary  direction  so  as  to  rub  and  polish 
the  surfaces  of  the  candles.  A  small  circular  saw,  G,  trims  the 
bases  of  the  candles  as  they  emerge  from  the  tray,  A.  Paraffin 
candles  as  a  rule  are  sufficiently  smooth  and  glossy  when  properly 
moulded  without  any  additional  polishing. 

Nigh.tligh.ts. — The  use  of  "  mortars,"  or  mortuary  candles,  for 
burning  in  death  chambers,  etc.,  is  very  ancient,  wTax  tapers  being 
the  form  usually  employed  until  comparatively  recently,  when 
the  use  of  short  stumpy  candles  of  peculiar  composition  and 
construction  became  general  for  burning  at  night  under  such 
circumstances  that  whilst  only  a  feeble  illumination  is  requisite, 
the  flame  is  required  to  burn  steadily  and  constantly  for  a  number 
<  >f  hours  together. 

Two  different  forms  of  "  iiightlights  "  are  now  chiefly  employed, 
one  set  in  a  case  of  paper,  wood-shaving,  or  similar  material, 
sufficiently  fluid-tight  to  prevent  the  melted  combustible  material 
from  running  out ;  the  other  cast  into  shape  without  any  such 
covering.  The  wick  in  each  case  is  generally  supported  at  the 
base  by  a  "  sustainer,"  consisting  either  of  a  little  metal  disc  with 
;i  small  central  perforation  through  which  the  wick  passes,  or  a 
similar  small  plaster  of  Paris  plate,  &c.,  the  object  being  to 
prevent  the  wick  from  falling  over  when  the  light  has  nearly 
burnt  out  so  that  little  or  no  solid  grease  is  left  to  support  the 
wick.  The  nature  of  the  materials  burnt  varies  considerably ; 
for  encased  nightlights  substances  are  generally  chosen  the  fusing 
points  of  which  are  not  extremely  high,  so  that  the  cost  is  less ; 
while  for  nightlights  of  the  "pyramid"  kind  without  cases, 
substances  of  comparatively  high  melting  points  are  preferable. 

Different  manufacturers  vary  considerably  in  the  way  in  which 
their  nightlights  are  prepared.  Tn  some  instances  the  pasteboard 
or  wooden  case  is  simply  filled  up  with  melted  candle  material 
from  a  can  after  the  bit  of  wick  and  "sustainer"  are  fixed  in 
position  by  means  of  a  drop  of  melted  grease  applied  after  the 
wick  has  been  passed  upwards  through  a  minute  hole  in  the 
bottom  of  the  box  :  such  nightlights  are  generally  placed  in  a 
saucer  of  water  when  burnt.  Others  are  moulded  round  the 
wicks  in  much  the  same  fashion  as  ordinary  longer  candles ;  whilst 
others  are  cast  as  solid  cylinders  of  fatty  matter,  through  the 
centre  of  which  a  hole  is  perforated;  the  wick  previously  threaded 
on  a  little  bit  of  tinfoil,  is  passed  upwards  through  the  perforation, 


N1GHTLIGHTS.  407 

and  fixed  in  position  sufficiently  securely  by  a  blow  carefully  given 
with  a  peculiar  kind  of  hammer  :  these  are  generally  burnt  in 
glass  dishes  without  water.  Palmitic  acid  from  palm  oil,  highly 
pressed  coker  stearine,  and  pressed  tallow  are  the  materials  most 
frequently  employed  as  combustible  matter ;  wicks  of  rush  pith 
peeled  so  that  two  small  strips  of  peel  are  left  adherent  on  oppo- 
site sides  are  used  for  some,  the  effect  of  the  strips  being  to  turn 
outwards  in  burning,  giving  a  well-shaped  flame. 

Spills  for  lighting  candles,  &c.,  are  generally  drawn  by  much 
the  same  process  as  that  above  described  for  thin  wax  tapers 
(p.  389),  the  wicks  being  wound  on  a  drum  after  passing  through 
the  melted  composition  and  a  suitable  sized  drawplate.  After 
cutting  to  length  the  ends  are  "feathered'"'  by  dipping  into  hot 
water  so  as  to  melt  half  an  inch  or  so  of  composition  and  giving 
n  vigorous  shake  or  jerk  which  dislodges  most  of  the  melted 
materials,  slightly  separating  the  strands  in  so  doing. 

Medicated  Candles. — For  the  purpose  of  impregnating  the 
air  of  sickrooms,  &c.,  with  disinfecting  vapours,  certain  substances 
are  sometimes  intermixed  with  the  candle  material — e.g.,  iodine 
and  eucalyptus  oil.  In  the  latter  case  the  effect  is  produced  by 
the  volatilisation  of  eucalyptol  from  the  hot  cup  of  melted  grease 
at  the  base  of  the  wick,  that  portion  which  is  burnt  in  the  flame 
being  ineffective ;  with  iodine,  the  free  element  is  evolved  from 
the  flame  itself,  hydriodic  acid,  if  formed,  being  largely  decom- 
posed again  by  the  heat.  Sulphur  *  has  been  used  in  similar 
fashion,  sulphur  dioxide  being  formed  on  combustion. 

"::  A  spirit  lamp  charged  with  a  mixture  of  alcohol  and  carbon  disulphide 
affords  a  convenient  means  of  producing  sulphur  dioxide  for  disinfecting 
chambers,  &c. 


408  OILS,    FATS,    WAXES,    ETC. 


§  7.  The  Soap  Industry. 


CHAPTER    XVIII. 
MATERIALS  USED  IN  THE  MANUFACTURE  OF  SOAP. 

FATTY  MATTERS  AND  ALKALIES. 

THE  raw  fatty  materials  employed  in  any  large  quantities  for 
the  manufacture  of  ordinary  household  soaps  and  those  used  for 
technical  purposes,  such  as  wool  -  scouring,  &c.,  are  far  less 
numerous  than  the  different  varieties  of  oleaginous  matters 
used  for  culinary,  edible,  and  miscellaneous  purposes  through- 
out the  world  in  different  countries ;  but  almost  every  day 
new  sources  of  oily  and  fatty  matters  from  abroad  are  brought 
to  light,  many  of  which  only  require  suitable  development  to 
furnish  excellent  material  for  soapmaking  as  well  as  for  more 
superfine  uses. 

The  leading  substances  of  animal  origin  in  largest  use  for  soap- 
making  are  the  fats  of  the  sheep  and  ox  (tallow),  horse  grease, 
damaged  hog's  lard,  kitchen  grease,  and  similar  materials  derived 
from  trade  refuse  of  different  kinds  (such  as  tannery,  bone- 
boiling  and  gluemaking  greases),  together  with  seal  and  whale 
oils,  cod  and  shark  liver  oils,  fish  oils  of  various  kinds,  and 
such  like  materials,  including  sewage  grease,  egg  yolks,  and 
greases  recovered  from  soapsuds,  wool  washing,  engine  waste 
cleansing,  &c.  Amongst  the  more  prominent  materials  of  vege- 
table origin  may  be  mentioned  the  oils  and  butters  derived  from 
olives ;  cotton,  sesame,  sunflower,  rape,  and  linseeds ;  arachis 
and  cokernuts  ;  palm  fruits  and  kernels  ;  niger  and  poppy  seeds  ; 
castor  beans  and  almonds ;  and  in  lesser  degree  a  large  variety  of 
analogous  substances,  mostly  either  the  "  foots  ;'  formed  during 
refining  (p.  261),  or  the  interior  qualities  obtained  as  the  last 
hot  pressings,  or  by  treatment  with  carbon  di sulphide  and  similar 
solvents,  of  the  partially  exhausted  mass  from  which  oils  of  finer 
quality,  suitable  for  superior  applications,  have  been  previously 
expressed  or  otherwise  obtained ;  it  being  a  sort  of  general 


ALKALIES.  409 

axiom  that  any  kind  of  greasy  or  oleaginous  matter  can  be  made 
into  soap  of  a  more  or  less  useful  and  valuable  character,  even 
when  fit  for  no  other  applications,  the  coarsest  kind  of  cart  grease 
and  such  like  rough  lubricants  alone  excepted. 

A  certain  amount  of  higher  priced  soaps  (toilet  and  special 
varieties)  is  also  prepared  from  less  coarse  fatty  matters,  in  some 
instances  from  materials  of  the  finest  qualities  ;  but  the  quantity 
of  these  superior  grades  made  bears  only  a  small  proportion  to 
the  total  amount  of  ordinary  coarser  soaps  manufactured  for 
scouring  and  laundry  purposes  (vide  Chap,  xx.) 

Alkalies. — The  term  alkali  is  usually  traced  to  the  Arabic 
Al  kali,  a  name  applied  to  a  particular  plant  (a  kind  of  "  glass- 
wort  "),  the  ashes  of  which  abound  in  potash,  and  have  conse- 
quently been  used  from  the  earliest  ages,  not  only  for  the  manu- 
facture of  glass  (whence  the  English  trivial  name),  but  also  for 
laundry  and  detergent  purposes  generally.  The  term  "  potash," 
indeed,  connotes  much  the  same  idea,  being  originally  applied  to 
the  soluble  part  of  woodashes  dissolved  out  by  water  and  re- 
covered by  boiling  down  the  solution  in  a  pot ;  pearlash  being 
the  same  material  subjected  to  further  purification  so  as  to 
whiten  it.  Even  at  the  present  d^y  crude  ashes  from  vegetable 
combustibles  are  often  used  as  a  detergent  without  purification, 
the  earthy  and  calcareous  insoluble  matters  present  serving 
rather  to  aid  scouring  purposes  ]  thus,  cigar  ash  furnishes  a 
very  effective  dentifrice.* 

The  difference  in  character  (from  the  soap  boiler's  point  of 
view)  between  the  alkali  contained  in  the  ashes  of  inland  vege- 
tation (potash)  and  that  present  in  marine  plant  ash  (soda), 
appears  to  have  been  known  to  a  considerable  extent  to  the 
alchemists  of  the  earlier  and  middle  ages  of  the  Christian  era  ; 
although  the  essential  chemical  differences  between  the  two,  and 
the  practical  identity  of  the  latter  with  the  mineral  product 
natron,  were  probably  not  so  clearly  understood.  The  effect  of 
treatment  with  quicklime  so  as  to  render  "  mild  alkali "  (car- 
bonate) "quick"  or  "caustic,"  and  the  superior  action  of  the 
quickened  product  on  oleaginous  matters,  so  as  to  form  soap, 
were  also  more  or  less  imperfectly  known  to  them.  At  the  pre- 
sent day  the  alkalies  used  in  soapmaking  are  generally  (though 
not  invariably)  used  in  the  caustic  condition  because  of  this  more 
rapid  action ;  but  saponification  can  be  effected  by  carbonated 
alkalies  if  sufficient  time  be  allowed,  or  if  the  action  be  acceler- 
ated by  increased  heat  and  pressure.  In  all  probability  the 
action  of  an  alkaline  carbonate  essentially  consists  in  the  forma- 

*  A  few  years  ago  an  ancient  tomb  was  duo;  up  in  Rome  ;  a  quantity  of 
what  appeared  to  be  ashes  were  found  therein,  which  were  appropriated 
by  one  of  the  workmen  for  his  wife  to  use  in  washing.  It  subsequently 
transpired  that  the  ashes  were  the  remains  of  the  Emperor  Galba,  who  was 
cremated  some  eighteen  centuries  ago  (Time*). 


410  OILS,    FATS,    WAXES,    ETC. 

tion  of  soap  and  bicarbonate ;  thus  with  stearin  and  sodium 
carbonate — 

Stearin.  Sodium  Carbonate.  Water.  Glycerol. 

C3H5(C18H3502)3      +      3NaaC03      +      3H,0  C3H5(OH)3 

Sodium  Stearate.         Sodium  Bicarbonate. 

+      3Na(C]8H35O2)     +     3NaHCO3. 

Under  the  influence  of  heat  the  bicarbonate  breaks  up  into 
carbon  dioxide,  water,  and  neutral  carbonate,  which  last  then 
reacts  as  before — 

Sodium  Bicarbonate.  Sodium  Carbonate.         Carbon  Dioxide.  Water. 

2NaHC03  Na2C03         +         C02         +         H20. 

Ammonia  usually  exerts  a  considerably  less;  energetic  saponi- 
fying action  on  most  kinds  of  fatty  matters  than  the  fixed 
.alkalies ;  whilst  lime,  magnesia,  zinc  oxide,  lead  oxide,  and 
.similar  materials,  although  useful  in  the  preparation  of  earth}' 
and  metallic  soaps  for  other  purposes  (candlemaking,  preparation 
of  lead  plasters,  tfec.),  are  not  used  in  the  direct  manufacture 
of  ordinary  soaps  ;  excepting  in  so  far  as  small  quantities  of  lime, 
iron,  and  other  metallic  soaps  are  often  present  therein  as  im- 
purities derived  from  the  water  or  the  materials  and  utensils 
used,  &c. 

Formerly  the  manufacture  of  alkali,  especially  soda,  was  very 
frequently  conjoined  with  that  of  soap  ;  but  of  late  years  it  has 
become  more  usual  to  dissever  the  two  trades,  the  soapboiler 
purchasing  either  caustic  or  carbonated  alkali  from  the  alkali 
manufacturer  instead  of  preparing  it  himself.  At  one  time  the 
chief  source  of  potash  was  the  ashes  of  terrestrial  vegetation 
/whence  the  term  "  vegetable  alkali ") ;  but  mineral  potassium 
chloride  (chiefly  from  the  Stassfurth  deposits)  is  now  largely 
employed  as  raw  material,  being  converted  into  potassium 
carbonate  by  the  Leblanc  process.*  Similarly,  in  the  earliest 
ages,  soda  (natron)  was  derived  from  saline  efflorescences  on  the 
soil,  whence  the  term  "  mineral  alkali ;"  subsequently,  the  ashes 
of  seaweeds  and  marine  plants  furnished  a  cheaper  source  known 
as  "barilla;"  whilst  latterly,  soda  produced  by  the  method  of 
Leblanc,  or  by  the  more  recent  "ammonia  process"  for  converting 
rocksalt  into  sodium  carbonate,  has  mostly  superseded  all  other 
kinds.  By  either  of  these  processes,  "soda  ash"  (more  or  less 
impure  anhydrous  sodium  carbonate)  and  "caustic  soda"  (sodium 
hydroxide)  are  prepared  in  the  solid  state,  the  latter  being 
usually  put  up  in  airtight  iron  drums  for  transport  and  preserva- 
tion ;  when  caustic  liquors  of  a  given  strength  are  requisite,  they 

*  Conversion  into  sulphate  by  treatment  with  sulphuric  acid,  and  subse- 
quent heating  of  the  sulphate  with  small  coal  and  calcium  carbonate,  so  as 
to  form  alkaline  carbonate  and  calcium  sulphide  (as  "black  ash"),  separated 
by  dissolving  out  the  former  by  means  of  water. 


CAUSTICI8IN6    PROCESS.  411 

are  readily  prepared  by  simply  dissolving  a  known  weight  of  the 
solid  caustic  soda  in  a  given  volume  of  water,  and  are  then  ready 
for  use.  When,  however,  sodium  carbonate  or  potassium 
carbonate  is  bought,  before  caustic  leys  suitable  for  soap  boiling 
can  be  obtained,  the  operation  of  "  causticising  "  must  be  gone 
through,  consisting  in  dissolving  the  carbonated  alkali  in  water, 
adding  lime,  and  boiling  up  with  agitation  so  that  the  calcium 
hydroxide  and  alkaline  carbonate  may  react  on  one  another  in 
accordance  with  the  equations  — 

Sodium  Carbonate.  Slaked  Lime.  Caustic  Soda.  Calcium  Carbonate. 

+          CaHA          =   .       2NaOH          +          CaC0 


Potassium  Carbonate.         Calcium  Hydroxide.        Potassium  Hydroxide.        Calcium  Carbonate. 

K._,CO,          +          CaFLO,  2KOH          +          CaC03 

Causticising  Process.  —  Tii  the  earlier  days  of  soapmaking 
the  causticising  of  the  alkalies  employed  was  generally  effected 
in  the  cold  ;  a  purer  ley  being  thus  obtained  from  crude  "  ashes  " 
(rough  potashes  and  "black  ash")  than  when  the  whole  was 
boiled  up  together,  and  then  allowed  to  settle.  At  the  present 
<lay  this  method  of  treatment  is  but  seldom  employed  in  this 
country,  although  still  in  use  on  the  Continent.  In  order  to 
carry  it  out  to  the  best  advantage  the  bottom  of  the  vat  is 
covered  with  lumps  of  quicklime,  over  which  water  is  thrown  to 
slake  it  ;  5  parts  of  soda  ash  *  for  every  6  of  quicklime  originally 
used  are  then  shovelled  in  on  the  top  as  uniformly  as  possible. 
Another  layer  of  lime  is  then  added,  and  a  second  of  soda  ash, 
equal  in  weight  to  the  lime  ;  then  a  third  layer  of  lime,  and  a 
third  of  soda  ash,  equal  to  the  second  layers.  Water,  or  weak 
runnings  from  a  previous  batch,  is  then  gradually  run  on,  and 
the  whole  allowed  to  stand  till  next  day,  when  the  caustic  soda 
ley  formed  is  run  off  through  a  cock  at  the  base  of  the  vat  into 
<i  settling  tank.  More  water  is  then  added  and  allowed  to  stand 
as  before,  and  finally  run  off,  giving  a  much  weaker  liquor  either 
mixed  with  the  first,  or  used  for  lixiviating  another  batch.  The 
lime  mud  is  then  stirred  up  with  more  water,  and  the  final  weak 
liquor  thus  obtained  used  to  work  a  new  batch.  Conveniently 
three  (or  even  four)  vats  are  worked  in  series,  exactly  like  black 
ash  lixiviating  tanks;  the  second  liquor  from  No.  2  is  passed 
through  No.  1,  coming  out  of  full  strength,  being  itself  obtained 
as  the  third  liquor  from  No.  3,  which  is  then  exhausted.  No.  3, 
being  refilled,  then  becomes  No.  1  of  a  new  series  ;  the  former 
No.  1  becomes  the  second;  and  so  on,  methodically.  Crude 
Leblanc  soda  liquors  are  much  less  frequently  used  now  than 

*  Theoretically,  106  parts  of  Na2C03  are  equivalent  to  56  parts  of  CaO  ; 
a  considerable  excess  of  lime,  however,  is  requisite  to  ensure  causticising 
in  the  cold.  For  steam  boiling  in  practice  200  parts  of  soda  ash  are  used 
per  100  of  quicklime. 


412 


OILS,    FATS,    WAXES,  ETC. 


was  the  case  before  the  ammonia  soda  process  had  made  much 
headway ;  when  carbonated  alkali,  free  from  sulphide,  is  treated 
(as  when  ammonia  soda  ash  is  employed,  or  Leblanc  soda  ash 
prepared  from  the  "  salts  "  that  separate  on  evaporating  the  crude 
liquors  obtained  on  lixiviating  black  ash),  the  plant  used  consists 
simply  of  some  form  of  steam  vessel,  such  as  an  old  boiler,  pro- 
vided with  an  efficient  agitator ;  lumps  of  quicklime  are  added 
(preferably  placed  on  a  grating  or  enclosed  in  a  sort  of  cage  to 
keep  back  hard  lumps  and  stones  when  the  lime  disintegrates  by 
slaking),  and  the  whole  boiled  up  for  one  or  more  hours  until 
the  operation  is  complete,  either  under  pressure  in  a  closed  vessel 
(whereby  a  considerable  saving  of  fuel  and  labour  is  effected), 
or  by  means  of  wet  steam  in  an  open  pan.  If,  on  the  other 
hand,  crude  black  ash  liquors  be  used  (impure  sodium  carbonate, 
tfec.,  dissolved  out  from  black  ash  by  water,  containing  sulphide 
owing  to  the  reaction  of  sodium  carbonate"  solution  on  calcium 
sulphide),  or  the  "  red  liquors  "  obtained  as  mother  liquors  when 
the  crude  black  ash  liquor  is  evaporated  until  "  salts  "  (mostly 
sodium  carbonate)  crystallise  out  during  evaporation,  the  causti- 
cising  action  of  lime  is  conveniently  conjoined  with  the  oxidising 
action  of  a  current  of  air  blown  into  the  fluid  for  the  purpose  of 
destroying  sulphide  by  conversion  into  thiosulphate,  sulphite, 
and  sulphate  ;  for  which  purpose  a  vessel  is  employed  provided 
at  the  base  with  a  large  rose  jet  or  spiral  tube  pierced  with 
holes,  or  a  perforated  false  bottom,  through  which  the  air  and 
steam  are  blown  in  together  so  as  to  keep  the  whole  in  agita- 
tion and  effect  the  causticising  and  oxidation  simultaneously. 
Finally,  the  whole  is  allowed  to  stand  at  rest  awhile,  so  that 
the  "  lime  mud  "  (calcium  carbonate,  £c.)  may  settle,  and  the 
clear  caustic  alkali  solution  run  off  or  pumped  into  tanks  for 
storage.  These  are  generally  made  of  boiler  plate  rivetted 
together  (Fig.  107).  When  intended  to  hold  ley  for  toilet  soap, 

Dussauce  recommends  that  they 
should  be  lined  with  sheet  lead  to 
prevent  possible  discoloration  of 
soap  through  contact  of  the  ley 
with  iron. 

In  order  to  causticise  the  car- 
bonate thoroughly  an  excess  of 
lime  is  desirable  ;  the  remaining 
caustic  lime  in  the  lime  mud,  if 
of  sufficient  quantity  to  be  worth 
saving,  may  be  utilised  by  boiling 
up  again  with  a  fresh  batch  of 
carbonated  liquors  ;  after  allowing 


Fig.  107. 


to  settle,  the  clear  liquor  is  pumped  off  to  another  pan, 
where  the  causticising  is  finished  with  another  batch  of  fresh 
lime,  the  mud  from  which  operation  is  again  boiled  up  with 


CAUSTICISING    PROCESS.  413 

fresh  carbonated  liquor,  and  so  on  continuously  alternately.  The 
lime  mud  resulting  from  the  second  treatment  with  carbonated 
liquors  usually  contains  too  little  caustic  lime  to  be  worth  using 
a  third  time ;  but  by  boiling  up  with  water  the  adhering  soda 
solution  is  mostly  washed  out,  and  a  weak  ley  obtained,  utilised 
either  to  dissolve  more  carbonated  alkali,  or  for  other  purposes 
in  the  factory.* 

To  ciusticise  sodium  carbonate  solution  thoroughly,  the  liquor 
must  not  be  too  strong,  otherwise  a  considerable  portion  of  the 
alkaline  carbonate  escapes  the  causticising  action  of  the  lime ;  on 
the  other  hand,  when  the  leys  are  made  too  weak,  the  quantity  of 
salt  subsequently  requisite  for  "  salting  out "  the  soap  (Chap,  xx.) 
is  increased.    When  the  open  pan  system  is  adopted,  a  sufficiently 
complete  degree  of  causticising  is  generally  effected  by  using 
liquors   of  such   strengths   that  the  ley  finally  obtained  has  a 
specific  gravity  not  exceeding  about  1-075  to  I'lO  (15°  to  20°  Tw.), 
although  slightly  higher  strengths,  up  to  specific  gravity  I'll  or 
1'125   (22°  to   25°   Tw.),  are  sometimes  made;  by  causticising 
under  pressure,  considerably  stronger  leys  may  be    effectively 
prepared,  provided  that  the  subsidence  of  the  lime  mud  and  the 
running  off  of  the  clear  ley  is  still  effected   under   the   same 
pressure ;  thus,  with  a  pressure  of  50  Ibs.  per  square  inch,  caustic 
leys  up  to  specific  gravity  1-16  to  1'20  (32°  to  40°  Tw.)  may  be 
readily  prepared,  provided  this  precaution  is  adopted  ;  otherwise 
the   reverse  action  goes   on,   caustic   soda  reacting  on    calcium 
carbonate  so  as  to  reproduce  sodium  carbonate  (Parnell).     When 
more   concentrated   leys    are   required,    they  are    obtained    by 
quickly  boiling  down  with  as  little   access  of  air  as  possible ; 
weaker  leys  are  got  by  diluting  stronger  ones  with  water,  or 
with   the   very  weak  liquors  obtained  by  "  washing "  the  lime 
mud  left  after  running  off  the  caustic  liquor — i.e.,  by  adding 
water  to  the  mud,  boiling  up,  allowing   to  settle,  running  off 
the  weak  ley  thus  obtained,  and  repeating  the  operation  so  as  to 
obtain   another    batch   of  still   weaker  washings.     The    storage 
tanks  in  which  the  caustic  leys  are  kept  should  be  well  closed  to 
prevent  absorption  of  carbonic  acid  from  the  air ;  this  is  some- 
times done  by  pouring  a  layer  of  paraffin  oil  or  melted  paraffin 
wax  on  the  ley,  of  course  taking  the  requisite    precautions   to 
avoid  any  hydrocarbon  being  drawn  off  with  the  ley  used  for 
making  soap  ;  when  properly  prepared,  no  visible  disengagement 
of  bubbles  of  gas  should  be  noticeable  on  adding  sufficient  hydro- 

*  The  lime  mud  finally  obtained  from  soda  leys  usually  retains  a  notable 
proportion  of  sodiiim  carbonate  in  a  form  insoluble  in  water,  chiefly  as  a 
double  carbonate  of  calcium  and  sodium.  This  may  be  regained  in  Leblanc 
alkali  works  by  drying  and  using  the  impure  calcium  carbonate  obtained 
over  again  in  the  black  ash  operation  ;  but  in  an  ordinary  soap  work, 
where  the  residual  lime  mud  is  little  better  than  a  waste  product,  the  soda 
thus  retained  in  the  lime  mud  is  usually  lost. 


414  OILS,    FATS,    WAXES,    ETC. 

chloric  or  other  mineral  acid  to  supersaturate  the  alkali ;  this 
serves  as  a  test  of  completion  during  the  causticising  process. 
In  order  to  know  what  quantity  of  alkali  is  used  for  a  given 
operation,  the  tanks  are  fitted  with  gauges ;  so  that  if  the  level 
is  reduced  by  a  given  number  of  inches,  for  instance,  it  is  known 
that  so  many  gallons  of  fluid  have  been  run  off ;  the  alkaline 
strength  of  the  fluid  being  known,  the  total  weight  of  alkali 
present  in  the  fluid  run  off  is  then  known.  In  general  it  is 
more  convenient  to  arrange  the  ley  tanks  at  an  elevation  (in 
the  upper  part  of  the  factory)  so  as  to  run  off  the  leys  by 
gravitation,  than  to  have  them  in  the  basenient  and  pump 
up  the  leys  to  the  coppers,  although  this  latter  arrangement 
economises  space. 

Valuation  of  Alkalinity  of  Leys. — In  order  to  determine 
the  alkaline  strength  of  soap  leys  with  absolute  accuracy,  a 
volumetric  assay  with  a  standard  acid  solution  must  be  employed  ; 
but  for  general  soapmaking  purposes,  the  specific  gravity  of  the 
solution  is  a  sufficiently  near  indication.  It  should  be  borne  in 
mind,  however,  that  the  specific  gravity  is  only  to  be  trusted  as 
an  indication  of  alkalinity  in  cases  where  the  character  of  the 
liquor  is  always  sensibly  the  same — i.e.,  where  the  proportion  of 
saline  matters  other  than  caustic  alkali  (sodium  or  potassium 
chloride,  sulphate,  &c.)  does  not  vary  much.  This  is  usually  the 
case  when  soda  ash,  <fec.,  of  a  tolerably  uniform  quality  is  always 
employed ;  but  when  different  grades  are  used  at  different  times, 
leys  may  easily  be  obtained  of  considerably  different  alkaline 
strengths  although  of  the  same  specific  gravity.  Thus,  if  soda 
ash  be  used,  made  by  the  ammonia  process  and  containing  say 
56  per  cent,  of  "  anhydrous  soda "  (Na0O  =  62),  equivalent  to- 
about  96  per  cent,  of  anhydrous  sodium  carbonate,  Na2CO3,  a  ley 
having  a  given  specific  gravity  (say  1-075)  at  the  ordinary 
temperature  will  be  notably  stronger  in  alkali,  bulk  for  bulk, 
than  a  similar  ley  prepared  from  Leblanc  soda  of  say  52  per  cent., 
equivalent  to  about  89  per  cent,  of  anhydrous  carbonate,  because 
the  latter  contains  a  larger  proportion  of  sodium  salts  (chloride, 
sulphate,  &c.),  which  increase  the  relative  density  of  the  liquor 
without  adding  to  its  alkaline  strength.  A  fortiori,  if  a  "48  per 
cent,  soda  ash "  (i.e.,  an  ash  containing  alkali  equivalent  to 
only  48  per  cent,  of  Na.,O,  equivalent  to  about  82  per  cent,  of 
Na2CO3)  be  used,  the  alkaline  strength  of  the  ley  will  be  lower 
still  for  the  same  specific  gravity,  since,  in  order  to  reduce  the 
alkalinity  of  the  ash  to  "48  degrees"  (48  per  cent.  Ka2O),  an 
extra  amount  of  some  diluting  agent  (usually  salt)  must  be 
added.  Similar  remarks  obviously  apply  to  potash  leys  made 
from  potash  of  different  grades,  and  to  caustic  soda  leys  made 
by  directly  dissolving  solid  caustic  soda  in  water;  the  ley 
from  a  "  70  per  cent,  caustic "  (containing  70  per  cent. 
=  about  90  per  cent.  NaOH)  will  usually  be  stronger, 


ALKALINITY    OP    LEYS. 


415 


bulk  for  bulk,  at  a  given  specific  gravity  than  that  from  a 
"  60  per  cent,  caustic "  (containing  60  per  cent.  Na2O  =  about 
77  per  cent.  NaOH),  except  in  so  far  as  the  difference  in 
strength  between  the  two  kinds  of  caustic  is  due  simply  to  water, 
and  not  to  saline  matters,  such  as  sulphate  and  chloride. 

The  following  tables  exhibit  the  relationships  between  the 
alkaline  strengths  of  pure  solutions  of  sodium  and  potassium 
hydroxides  and  carbonates,  and  their  respective  specific  gravities, 
at  the  ordinary  temperature  (15°  C.),  or  at  more  elevated  tem- 
peratures : — 

* 
SPECIFIC  GRAVITV  OF  CAUSTIC  SODA  SOLUTION  AT  15°  (Tunnermanri). 


Specific  Gravity. 

Per  Cent,  of  Na2O 

Specific  Gravity. 

Per  Cent,  of  Na20. 

1-42S5 

30-22 

1  -2392 

15-11 

1-4193 

29-62 

•2280 

14-50 

1-4101 

29-01 

•2178 

13-90 

1-4011 

28-41 

•2058 

13-30 

1-3923 

27-80 

•1948 

12-69 

1-383G 

27-20 

•1841 

12-09 

1-3751 

26-59 

•1734 

11-48 

1-3668 

25-99 

1-1630 

10-88 

1  -3580 

25-39 

1-1528 

10-28    - 

1  -3505 

24-78 

1-1428 

9-67 

1-3426 

24-18 

1-1330 

9-07 

1-3349 

23-57 

1-1233 

8-46 

1-3273 

22-97 

1-1137 

7-86 

1-3198 

22-36 

-1-1042 

7-25 

1  -3143 

21-89 

1-0948 

6-65 

1-3125 

21-76 

1-0855 

6-04 

1-3053 

21-15 

10764 

5-44 

1  -2982 

20-55 

1-0675 

4-84 

1  -2912 

19-95 

1-0587 

4-23 

1  -2843 

19-34 

1-0500 

3-63 

1  -2775 

18-73 

1-0414 

3-02 

1-2708 

18-13 

1  -0330 

2-42 

1-2642 

17-53 

1-0246 

1-81 

1-2578 

16-92 

1-0163 

1-21 

1-2515 

16-38 

1  -0081 

1-60 

1-2453 

15-71 

1  -0040 

1  30 

416 


OILS,    FATS,    WAXES,    ETC. 


SPECIFIC  GRAVITY  OF  CAUSTIC  SODA  SOLUTION  AT  15° 
(Lunge  and  Hurter). 


Specific  Gravity. 

Grammes  of  Na20 
per  Litre. 

Specific  Gravity. 

Grammes  of  Na20 
per  Litre. 

1-005 

3-7 

1-260 

228-9 

1-010 

7'5 

1  270 

240-0 

1-020 

15  1 

1-280 

251-0 

1  -030 

22-6 

1  -290 

252-1 

1-040 

30-2 

•300 

273-2 

1  -050 

377 

•310 

285-4 

1-060 

45-5 

•320 

297-7 

1-070 

53-2 

•330 

309-9 

1-080 

61-0 

•340 

322-2 

1-090 

68-8 

•350 

334-4 

1-100 

76-5 

•360 

347-2 

1-110 

84-3 

•370 

360-1 

1-120 

92  -1 

•380   . 

372-9 

1-130 

100-5 

•390 

385-7 

1-140 

109-6 

•400 

398-5 

1-150 

118-6 

•410 

411-8 

1-1(50 

1277 

•420 

4250 

1-170 

136-8 

•430 

438-2 

1-180 

145-8 

•440 

451-4 

1-190 

154-9 

•450 

464-6 

1-200 

l'J4-0 

•460 

479-9 

1-210 

174-7 

•470 

495-3 

1-220 

185-5 

•480 

510-6 

1  -230 

196-3 

•490 

525-9 

1-240 

207-0 

•500 

541-2 

1-250 

217-8 

INFLUENCE  OF  TEMPERATURE  ox  THE   SPECIFIC  GRAVITY  OF 
CAUSTIC  SODA  SOLUTION. 


Temperature. 

Specific  Gravity. 

Degrees  C. 

0          1-015 

1-030 

1-060!  1-100 

•150 

1-200 

1-250 

1  -320 

•370 

10 

1-012 

1-027 

1-057  1  1-097 

•146 

1-195 

1-245 

1315 

•365 

20 

1-009 

1-024 

1  054'  1-093 

•142 

1-190 

1-240 

1  -310 

•360 

30 

1  -007 

1-022 

1-052    1-091       -138 

1-186 

1-235 

1  -305 

•355 

40 

1  003 

1-018 

1-048    1-087       -136 

1-181 

1  -231 

1-299 

•350 

50 

0-999 

1-014 

1-044    1-082      -129 

1-177 

1-226 

1-294 

•345 

60 

•994 

1-009 

1-039    1-077      '124 

1-173 

1-221 

1-288 

•339 

70 

•988  !  1  -003 

1-033    1-071 

•118 

1-168 

1-216 

1  '283  1  1  -334 

80 

•982 

•997 

1-027    1-065 

1-112 

1-162 

1-211 

1-277 

1-329 

90 

•977 

•992 

1-022  [  1-059 

1-107 

1-156 

1-206 

1-271 

1-324 

100 

•971 

•986 

1-016    1-053 

1  101 

1-151 

1-200 

1-265 

1-319 

ALKALINITY    OF    LEYS. 


417 


SPECIFIC  GRAVITY  OF  CAUSTIC  POTASH  SOLUTION  AT  15°  (Tunnermann). 


Percentage  of 

Percentage  of 

Specific 

SpeciSc 

Gravity. 

KHO. 

K30. 

Gravity. 

KHO. 

K20. 

1-3300 

33-69 

28-29 

1-1437 

16-85 

14-15 

1  -3131 

32-35 

27-16 

1-1308 

15-50 

13-01 

1-2966 

31-00 

26-03 

1-1182 

14-15 

11-88 

T2805 

29-65 

2490 

1-1059 

12-80 

10-75 

1-2648 

28-30 

2376 

1-0938 

11-46 

9-62 

1-2493 

26-95 

22-63 

1-0819 

10-11 

8-49 

1-2342 

25-61 

21-50 

1-0703 

8-76 

7-36 

1-2268 

24-93 

20-94 

1-0589 

7-41 

6-22 

1-2122 

23-59 

19-80 

1  -0478 

5-96 

5-00 

1-1979 

22-24 

18-67 

1  -0369 

4-72 

3-96 

1-1839 

20-89 

17-54 

1  -0260 

3-67 

2-83 

1-1702 

19-54 

16-41 

1-0153 

2-02 

1-70 

1-1568 

18-20 

15-28 

1  -0050 

0-674 

0-566 

SPECIFIC  GRAVITY  OF  CAUSTIC  POTASH  SOLUTION  AT  15°. 
(Lunge  and  Hurter). 


Grammes  per  Litre. 

Grammes  per  Litre. 

Specific 
Gravity. 

Specific 
Gravity. 

K20. 

KOH. 

K20. 

KOH. 

1-007 

7 

9 

1-252 

284 

338 

1-014 

14 

17 

1  263 

297 

353 

1-022 

22 

26 

1-274 

308 

368 

1-029 

30 

36 

1-285 

321 

385 

1-037 

39 

46 

1-297 

335 

398 

1-045 

49 

58 

1-308 

349 

416 

1-052 

57 

67 

1-320 

363 

432 

1-060 

66 

78 

1-332 

377 

449 

1-067 

74 

88 

•345 

394 

469 

1-075 

83 

99 

•357 

410 

487 

1-083 

92 

109 

•370 

425 

506 

•091 

100 

119 

•383 

440 

522 

•100 

111 

132 

•397 

457 

543 

•108 

119 

143 

•410 

472 

563 

•116 

129 

153 

•424 

490 

582 

•125 

140 

167 

•438 

509 

605 

•134 

150 

178 

•453 

530 

631 

•142 

159 

188 

•468 

549 

655 

•152 

170 

203 

•483 

571 

679 

1-162 

181 

216 

•498 

593 

706 

1-171 

192 

228 

•514 

615 

731 

1-180 

203 

242 

•530 

635 

756 

1-190 

214 

255 

•546 

655 

779 

1-200 

226 

269 

•563 

681 

811 

1-210 

237 

282 

•580 

706 

840 

1-220 

248 

295 

1-597 

731 

870 

1-231 

260 

309 

1-615 

759 

902 

1-241 

272 

324 

1-634 

789 

940 

418 


OILS,    FATS,    WAXES,    ETC. 


SPECIFIC  GRAVITY  AT  15°  C.   or  SODIUM  CARBONATE  SOLUTION 
(Lunge  and  Hurter). 


Specific 
Gravity. 

Percentage  of 

Specific 
Gravity. 

Percentage  of 

NacO. 

Na2C03. 

Na20. 

Na2C03. 

1-005 

0-28 

0-47 

1-080 

4-42 

7-57 

1-010 

0-56 

0-95 

T085 

4-70 

8-04 

1-015 

0-84 

1-42 

1-090 

4-97 

8-51 

1-020 

1-11 

1-90 

1-095 

5'24 

8-97 

1-025 

1-39 

2-38 

1-100 

5-52 

9-43 

i 

1-030              1-67 

2-85 

1-105 

5-79 

9-90 

1-035 

1-95 

3-33 

1-110 

6-06 

10-37 

1-040 

2'22 

3-80 

1-115 

6-33 

10-83 

1-045 

2-50 

4-28 

1-120 

6-61 

11-30 

1-050 

2-78 

4-76 

1-125 

6-88 

11-76 

1  -055 

3-06 

5-23 

1-130 

7-15 

12-23 

1-060 

3-34 

5-71 

1-135 

7-42 

12-70 

1-065 

3-61 

6-17 

1-140 

770 

13-16 

1-070 

3-88 

6-64 

1-145 

7-97 

13-63 

1-075 

4-16 

7-10 

1-150 

8-24 

14-09 

SPECIFIC  GRAVITY  AT  30°  C.   OF  CONCENTRATED  SODIUM  CARBONATE 
SOLUTION  (Lunge  and  Hurter). 


Specific 
Gravity. 

Percentage  of 

'Specific 
Gravity. 

Percentage  of 

Na20. 

Na2C03. 

Na20. 

Na2C03. 

1-140 

7-97 

13-62 

1-230               12-48 

21-33 

1-150 

8-46 

14-47 

1-240 

12-98 

22-20 

1-160 

8-96 

15-32 

1-250 

13-49 

23-07 

1-170 

9-46 

16-18 

1-260 

14-00 

23-93 

1-180 

9-96 

17-04 

1-270 

14'49 

24-77 

1-190 

10-46 

17-89 

1-280 

14-98 

25-61 

1-200 

10-97 

18-75 

1-290 

15-47 

26-45 

1-210 

11-47 

19-61 

1-300 

15-96 

27-29 

1-220 

11-97 

20-47 

1-310 

16-45 

28-13 

CORRECTION    FOR    IMPURITIES. 


419 


POTASSIUM  CARBONATE  (Gerlach). 


Percentage 
of  K2C03. 

Specific 
Gravity  at  15°. 

Percentage 
of  K2C03. 

Specific 
Gravity  at  15°. 

Percentage 
of  K2C03. 

Specific 
Gravity  at  15°. 

1 

1-0091 

19 

1-1827 

37 

1-3828 

2 

1-0183 

20 

1-1929 

38 

1-3948 

I 

1-0274 

21 

1-2034 

39 

1-4067 

4 

1-0366 

22 

1-2140 

40 

1-4187 

5 

1-0457 

23 

1-2246 

41 

1-4310 

6 

1-0551 

24 

1-2352 

42 

1-4434 

7 

1-0645 

25 

1-2458 

43 

1-4557 

8 

1  -0740 

26 

1-2568 

44 

1-4681 

9 

1  -0834 

27 

1-2679 

45 

1  -4804 

10 

1-0928 

28 

1-2789 

46 

1-4931 

11 

1-1026 

29 

1-2900 

47 

1-5059 

12 

1-1124 

30 

•3011 

48 

1-5186 

13 

1-1222 

31 

•3126 

49 

1-5314 

14 

1-1320 

32 

•3242 

50 

1-5441 

15 

1-1418 

33 

•3357 

51 

1-5573 

16 

1-1520 

34 

•3473 

52 

1-5705 

17 

1-1622 

35 

•3589 

52-024 

1-57079 

18 

1-1724 

36 

1-3708 

The  above  tables  only  apply  to  pure  solutions  of  alkaline  car- 
bonates and  hydroxides  ;  with  commercial  substances  containing 
other  neutral  saline  matters  (chloride,  sulphate,  &c.)  a  correction 
is  necessary  to  allow  for  the  increment  in  specific  gravity  brought 
about  by  the  presence  of  these  impurities  without  any  corre- 
sponding increase  in  alkaline  strength  :  the  amount  of  this  cor- 
rection necessarily  varies  with  the  proportion  and  nature  of  the 
saline  matter  present,  and  consequently  no  very  accurate  allow- 
ance on  this  score  is  practicable  in  most  cases  ;  but  an  approxi- 
mation sufficiently  near  for  most  practical  purposes  is  obtained 
by  assuming  that  the  effect  of  a  given  quantity  of  neutral  saline 
matter  in  increasing  the  specific  gravity  is  the  same  as  that  of 
the  same  quantity  of  actual  alkali ;  so  that  if  it  is  known  that  a 
given  sample  contains  n  per  cent,  of  neutral  saline  matters, 
together  with  100  -  n  per  cent,  of  actual  alkali  (reckoned  on  the 
sum  of  alkali  and  salts  as  100),  the  correction  is  obtained  by 
subtracting  from  the  tabular  number  corresponding  with  the 
particular  specific  gravity  n  per  cent,  of  its  value.  Thus,  for 
example,  if  a  solution  of  sodium  carbonate  be  made  from  a  soda 
ash,  &c.,  where  the  saline  impurities  (sulphate,  chloride,  &c.) 
jointly  represent  5  per  cent,  of  the  total  solids  dissolved  (the 
sodium  carbonate  consequently  representing  95  per  cent.),  the 
amount  of  sodium  carbonate  given  in  the  table  for  a  given 
specific  gravity  is  to  be  reduced  by  5  per  cent,  of  its  value. 
Similarly  if  the  actual  caustic  soda,  NaOH,  in  a  sample  of 
commercial  caustic  be  90  per  cent.,  and  the  saline  impurities 


420  OILS,    FATS,    WAXES,    ETC. 

10  per  cent.,  of  the  total  soluble  solid  matters  present  (exclusive 
of  moisture),  the  tabular  number  must  be  decreased  by  10  per 
cent,  of  its  value.  Where  more  exact  valuations  are  requisite, 
as  is  sometimes  necessary  in  order  to  avoid  using  excess  or 
deficiency  of  alkali,  specific  gravity  indications  must  be  dis- 
carded, and  the  results  of  alkalimetrical  assays  substituted 
for  them  ;  for  this  purpose  a  normal  or  seminormal  solution  of 
hydrochloric  or  sulphuric  acid  is  convenient,  using  an  indicator 
not  affected  by  carbon  dioxide  (litmus  employed  in  hot  solution, 
cochineal,  methyl  orange,  &c.)  * 

English,  French,  and  German  Degrees. — A  peculiar  trade 
custom  obtains  in  Britain  whereby  the  alkaline  strength  of 
soda  ash  and  caustic  soda  is  represented  as  higher  than  the 
truth  to  the  extent  of  about  1'32  per  cent,  or  1  part  in  76. 
This  is  brought  about  by  the  incorrect  assumption  that  the  atomic 
weight  of  sodium  is  24  instead  of  23  ;  whence  the  percentage 
of  Na2O  in  pure  sodium  carbonate,  Na2CO;],  is  reckoned  as 

^4  x  100  =  59-26,  instead  of  ^  x  100  -  58:49.  Hence  58-49 
108  lOb 

parts  of  soda  are  reckoned  as  5 9 -2 6,  thus  giving  an  error  in 
excess  of  0'77  in  58-49  =  1-32  in  100.  A  still  more  erroneous 
mode  of  calculation  was  recently  current  in  some  districts,  based 
on  the  same  assumption  that  Na  =  24  ;  only  in  this  case  the 
molecular  weight  of  Na2O  was  reckoned  as  64  instead  of  62, 
thus  giving  an  error  in  excess  of  2  parts  in  64  --=  3-23  parts  in 
100,  more  than  twice  the  former  error. 

In  Germany  the  alkaline  strength  is  usually  expressed  in 
"degrees"  representing  the  percentage  of  pure  Na2CO3  equi- 
valent to  the  alkali  present — i.e.,  pure  sodium  carbonate  would 
be  a  soda  ash  of  100°.  In  France  "  Descroizilles  degrees  "  are  in 
use,  representing  the  quantity  of  pure  sulphuric  acid,  H2SO4, 
neutralised  by  100  parts  of  soda  ash — i.e.,  pure  sodium  car- 
bonate, Na.,CO.?,  would  represent  a  product  of  strength  equal  to 

98 

_ —  x   100  =  92° -45   Descroizilles.      The.  relationships   between 

Descroizilles  and  German  degrees  and  the  true  percentage  of 
anhydrous  soda  (Na9O  =  31,  not  affected  by  the  above  named 
errors  in  excess  due  to  English  trade  customs)  are  consequently 
given  by  the  formula — 

*  When  it  is  required  to  determine  the  amount  of  alkali  present  in  the 
caustic  and  in  the  carbonated  state,  two  assays  are  requisite  ;  in  one  case 
the  total  alkali  is  determined  contained  in  a  given  volume  of  fluid  ;  in  the 
other  the  same  volume  of  solution  is  boiled  with  barium  chloride  or  nitrate, 
and  after  cooling,  made  up  to  double  the  original  bulk  with  water  ;  after 
subsidence  or  filtration  the  caustic  alkali  in  half  the  total  fluid  is  determined, 
and  the  amount  found  doubled  and  subtracted  from  that  found  in  the  first 
assay.  The  difference  represents  the  carbonated  alkali  present  with  more 
or  less  accuracy  according  as  access  of  carbonic  acid  from  the  air  has  been 
avoided  during  the  operations. 


ENGLISH,  FRENCH,  AND  GERMAN  DEGREES. 


421 


I) 

40 


G 
53 


where  S  is  the  alkaline  strength  expressed  as  percentage  of  Na2O 
(equivalent  31  —  sometimes  spoken  of  as  the  strength  in  "Gay 
Lussac  degrees  ")  ;  D  the  same  in  Descroizilles  degrees  (equivalent 
of  H.2SO4  =  49)  ;  and  G  the  same  expressed  in  German  degrees 
(equivalent  of  Na,CO3  =  53). 

From  this  formula  result  the  equations  — 


S 


D    - 


49  " 

31 
53  ° 

49 
31S 


G 


G     =      .— 


=  0-6327  D 

=  0-5849  G 

=  1-5806S 

=  0-3245  G 

-  1-7097  S 


=      £D     =     1-0316D 


The  following  table  represents  the  same  relationships — 


S. 

D. 

G. 

S. 

D. 

G. 

2 

3-16 

342 

42 

66-39 

71-81 

4 

6-32 

9-84 

44 

69-55 

75-23 

6 

9-48 

10-26 

46 

72-71 

78-66 

8      12-64 

13-68 

48 

76-87 

82-07 

10      15-81 

17-10 

50 

79-03 

85-48 

12      18-97 

20-52 

>52 

82-19 

88-90 

14      22-13 

23-94 

54 

85-35 

92-32 

16      25-29 

27-36 

56 

88-52 

95-74 

18      28-45 

30-78 

58 

91-68 

99-16 

20 

31-61 

34-20 

60 

94-84 

102-58 

22 

34-77 

37-62 

62 

98-00 

106-01 

24      37-93      41-04 

64 

101-16 

109-43 

2<i 

41-09      44-46 

66 

104-32 

112-85 

28      44-25      47-88 

68 

107-48 

116-27 

30 

47-42 

51-29 

70 

110-64 

119-69 

32 

50-88 

54-71 

72 

113-81 

123-10 

34 

53-74      58-13 

74 

116-97 

126-52 

36 

56-90      61-55 

76 

120-13 

129-94 

38 

60-06      64-97 

77  '5 

122-50 

132-50 

40 

63-22 

68-39 

Calculation  of  Quantity  of  Alkaline  Ley  requisite  for 
Saponiflcation. — When  an  alkaline  solution  of  known  strength 
(either  determined  by  titration,  or  inferred  from  the  specific 


422  OILS,    FATS,    WAXES,    ETC. 

gravity  after  correction  of  the  tabular  value  for  saline  impurities) 
is  to  be  used  for  converting  into  soap  a  given  kind  of  fatty  matter 
or  mixture  of  fats,  &c.,  the  quantity  requisite  for  exactly  saponi- 
fying a  given  weight  of  fat  depends  not  only  on  the  alkalinity 
of  the  ley  but  also  on  the  mean  saponification  equivalent  of 
the  fatty  matters  (p.  158) ;  the  lower  the  value  of  this  latter 
quantity  the  more  alkali  will  be  required,  the  relationship  being 
indicated  thus — Let  E  be  the  mean  saponification  equivalent  of 
the  fats,  etc.,  used  ;  then  E  units  of  weight  of  fat  will  be  equivalent 
to  31  units  of  Na2O  (or  to  40  of  NaOH,  47-1  of  K,O,  or  56-1 
of  KOH).  Let  1~000  parts  by  weight  of  alkaline  ley  be  equi- 
valent to  0J  parts  of  Na2O  (or  to  a.2  of  NaOH,  a3  of  K20,  or  «4  of 
KOH) — i.e.,  let  a1  («„,  as,  or  a4)  be  the  permillage  of  alkali  in 
the  ley.  Then  E  units  of  weight  of  fat  will  obviously  be  equi- 
valent to  31  x  — units  of  weight  of  ley  (or  to  40  x  — , 

al  \  #2 

1  000  1  000\ 

47-1  x  -' ,  or  56 -1  x          -  )  ;  whence  one  part  of  fat  is  equi- 

1,000        I4    31,000  /  40,000 

valent  to  31  x  -       -  x  =  =  -    — ^  parts  of  ley    or  to  -    — ^, 

a1  E       «1  x  L  A  \  a.2  x  Jjj 

— ,  or  — - — .,  parts).     Thus  one  part  by  weight  of  cokernut 

«3  x  E         «4  x  E  r        / 

oil  of  mean  saponification  equivalent  215  wrill  be  exactly  saponified 

by —  ,    r  =  0'846  parts  of  caustic  soda  ley  containing  220  per 

mille  of  NaOH  ;  whilst  one  part  of  linseed  oil  of  mean  saponifi- 
cation equivalent  291 '5  will  correspond  with  •=-  ?-=  =  1*077 

150  x  291-5 

parts  of  a  potash  ley  containing  total  active  alkali  (caustic  + 
carbonated)  equivalent  to  150  per  mille  of  K2O ;  and  so 
on. 

When  the  alkalinity  of  the  leys  is  expressed  as  parts  ~by  weight 
per  unit  of  volume  (grammes  per  litre,  pounds  per  gallon,*  &c.) 
the  above  calculation  still  applies  in  slightly  modified  form. 
Let  the  alkaline  ley  contain  bl  grammes  of  Na^O  per  litre  (b>2 
grammes  of  NaOH,  b3  of  K0O,  b±  of  KOH),  then  E  grammes  of 

.     .  31   ...  .  ,       /  40    47-1          56-1 

fat  are  equivalent  to  -  -   litres  of  ley  f  or  to  — -,  -y— ,   or  —=-• 

litres J  ;  whence  1  gramme  of  fat  represents    -.— ^  -^  for  7-^-^5 

*  A  solution  of  anything  containing  n  grammes  per  litre  (n  milligrammes 
per  c.c.  or  n  kilogrammes  per  cubic  metre),  contains  n  pounds  per  hecto- 
gallon  (100  gallons),  since  1  gallon  of  water  weighs  10  Ibs.  Hence  when 
laboratory  estimations  are  made,  as  usual,  on  the  metrical  system,  the 
results  can,  if  required,  be  referred  to  pounds  and  gallons  for  practical 
British  works'  use  in  a  "Very  simple  way. 


QUANTITY    OF    LEY    REQUISITE   FOR    SAPONIFICATION. 

,  or  T  --  ™         res  o 

56,100\ 


423 


y =,  v/x   ,     — ™ )  litres  of  ley ;    or  1    kilogramme  represents 

31,000    /40,000     47,100  56,100\ 

or    j-l—   )    litres.     Thus,    one   kilo. 


bt  x  E    \b2  x  E'    bs  x  E' 

of    cokernut    oil    (E  =  215)   would    be    exactly   saponified    by 

r.TTTT^ — JTT^-  =  0-930  litres  of  caustic  soda  solution  of  such 
200  x  21o 

strength  that  1  litre  =  200  grammes  NaOH;  or  1  kilo,  of  lin- 
seed oil  (E  =  291-5)  would  correspond  with  -^---7^-  OQ,  =  1'029 

10/  "U  X  ZiV I'D 

litres  of  potash  ley  of  which  1  litre  =  157'0  grammes  K2O. 

™     f  n       '        *  w        '  f  40'000        l   56'100  f 

Ihe  following  table  gives  the  values  of  — ^ —  and  — ^ —  for 

Talues  of  E  between  190  and  400 ;  by  its  means  the  number  of 
litres,  x,  of  caustic  soda  (or  potash)  solution  can  be  readily 
calculated,  requisite  for  the  saponification  of  a  kilogramme  of  any 
fatty  mixture  the  mean  saponification  equivalent  of  which  is  E, 
by  the  simple  formula — 

n 

X  =  TVf' 

where  n  is  the  tabular  number  corresponding  with  E,  and  N  the 
number  of  grammes  of  NaOH  (or  of  KOH)  contained  in  a  litre  of 
the  ley  used  : — 


E. 

40,000. 

Difference. 

56,100. 
E 

Difference. 

E 

190 

210-5 

295-2 

200 

200-0 

10  -5 

280-5 

14  7 

210 

190-5 

9-5  - 

267-2 

13-3 

220 

181-8 

8-7 

255-0 

12-2 

230 

173-9 

7-9 

243-9 

11-1 

240 

166-7 

7-2 

233-7 

10-2 

250 

160-0 

6-7 

224-4 

9-3 

260 

153-8 

6-2 

215-8 

8-6 

270 

148-1 

5-7 

207-8 

8-0 

280 

142-8 

5-3 

200-4 

7-4 

290 

137-9 

4-9 

193-5 

6-9 

300 

133-3 

4'6 

187-0 

6-5 

310 

129-0 

4-3 

181-0 

6-0 

320 

125-0 

4-0 

175-3 

5-7 

330 

121-2 

3-8 

170-0 

5'3 

340 

117-6 

3-6 

165-0 

5-0 

350 

114-3 

3-3 

160-3 

4-7 

360 

111-1 

3-2 

155-8 

4-5 

370 

108-1 

3-0 

151-6 

4-2 

380 

105-3 

2-8 

147-6 

4-0 

390 

102-6 

2-7 

143-8 

3-8 

400 

100-0 

2-6 

140-25 

3-55 

424  OILS,    FATS,    WAXES,    ETC. 

Thus,  suppose  a  mixture  of  tallow,  palm  oil,  and  cokernut  oil  to 
have  the  mean  saponification  equivalent  250  ;  then  n  =  160r 
and  the  number  of  litres  of  caustic  soda  solution  requisite  to 

saponify  a  kilogramme   is  — -^-->    where     N    is    the    number   of 

grammes  of  NaOH  contained  in  a  litre  of  the  ley;  if  N  =  1GO 
the  quotient  is,  obviously,  1,000 — i.e.,  1  litre  exactly  is  re- 
quired ;  whilst  for  stronger  and  weaker  solutions,  where  N  is 
respectively  320  and  80,  the  corresponding  quotient  values  are 
0-500  and  2 '000 — i.e.,  exactly  0*5  litre  of  the  stronger  fluid  is 
required,  and  2*0  litres  of  the  weaker  one. 

If  the  saponification  equivalent  is  not  exactly  indicated  by 
the  table,  the  value  is  readily  obtained  by  interpolation  by 
means  of  the  difference  columns  without  introducing  any  material 
error;  thus  a  commercial  "oleine"  (impure  oleic  acid)  of  which 
the  saponification  equivalent  is  282*5  corresponds  with  a  value 

A-0  000 
for  ^—  of  142-8  -  0-25  x  4'9  =  141-6;  hence,  if  a  soda  ley 

containing  293-6  grammes  of  NaOH  per  litre  be  used  (N  =  293*6), 

-1    A~\  ./?  .  -'. 

=  0-482    litre    of    ley    will    contain    alkali    exactly    corre- 

—  • ' '  *  *O 

spending  with  1  kilo,  of  fatty  matter. 

Obviously,    the    above    formula   x=  --7    will    also    enable    the 

number  of  parts  by  weight  of  ley  to  be  calculated,  requisite  to 
saponify  one  part  by  weight  of  fatty  matter  of  mean  equivalent 
E,  if  N  denote  the  permillage  of  NaOH  (or  of  KOH)  in  the 
ley.  Thus  in  one  of  the  examples  above  quoted,  one  part  of 

cokernut  oil  of  equivalent  215  represents  a  value  for  '  ,  -  of 
190'5  -  0-5  x  8-7=  186-1  ;  whence  the  quantity  of  soda  ley  at 
220  per  mille  of  NaOH,  equivalent  thereto  is  — —  =  0-846  part, 

as  before. 

When  it  is  required  to  use  fatty  matters  and  alkaline  leys  in 
as  nearly  as  possible  equivalent  quantities  so  as  to  avoid  excess 
of  either  constituent,  calculations  such  as  the  foregoing  afford 
the  simplest  method  of  arriving  at  the  relative  quantities 
requisite.  In  practice,  when  the  same  kind  of  operation  is 
to  be  repeated  over  and  over  again  as  a  matter  of  routine, 
the  fatty  matter  employed  being  sensibly  of  the  same  quality 
throughout,  it  usually  suffices  to  gauge  the  tanks  and  vessels 
employed  once  for  all  by  means  of  calculations  founded  on 
these  principles,  and  preferably  checked  by  careful  analyses 
of  the  resulting  products  ;  the  weight  of  fatty  matters  taken  and 
their  mean  saponification  equivalent  being  practically  constant 
for  each  operation,  the  volume  of  alkaline  ley  used  is  slightly 


QUANTITY    OF    LEY    REQUISITE    FOR    SAPONIFICATIOX.         425 

increased  or  diminished  below  that  corresponding  with  the 
original  gaugings  according  as  the  alkalimetrical  test  of  the 
liquor  (or  the  value  deduced  from  its  specific  gravity)  shows 
that  it  is  a  little  below  or  above  its  normal  strength — i.e.,  that 
pertaining  to  the  original  gaugings. 

When  it  is  required  to  calculate  the  amount  of  sodium  or 
potassium  hydroxide  or  carbonate  equivalent  to  a  given  amount 
of  anhydrous  oxide,  or  vice  versd,  the  following  formulae  may  be 
employed,  based  on  the  molecular  weights — 


Na  =  23 

Na20  =  6'2 

NaOH  =  40 

Na2C03  =  106 


K  39-1 

KoO  =  94  -2 

KOH  =  56'  I 

K2C03  =  138'2 


Let  a  given  weight  A  of  .Na.,O  be  equivalent  to  B  of 
and  C  of  Na.,CO3 ;  and  let  a  given  weight  D  of  K2O  be  equivalent 
to  E  of  KOH:  and  F  of  K2CO3  :  then— 

To  reduce  Formula. 

NaOH     to  Na20  A  ^^^    T>     =     °'""50  B 

Na2C03  to  Na20  A     =          ^       C     =     0-5849  C 

9    v    10 

Na20       to  NaOH  B      =       ^—     A     =     1-2903  A 

Na2C03  to  NaOH  B      =       '^T    C      =     0'7547  C 

Na20       to  Na2C03         C  ^       A  T7097  A 

106 
NaOH     to  Na2C03         C      =       ^   ™^     B     =     1-3250  B 

04-9 
KOH      to  K20  D     =     g^P^l  E     =     °'8396  E 

94 '2 
K2C03    to  KaO  D     =       -j^     F     =     0-6816  F 

K20        to  KOH  E      -     2-^4^  D     =     1  1911  D 

9    v    ^fi-1 

K2C03    to  KOH  E      -      -Tooo      F     =       '8119  F 

lOo    —t 

1  ^8  *2 

K20        to  K2C03          F      =         j~     D     =     1-4671  D 

1  qq  .o 

KOH      to  K2C03  F      -     o-^^Y  E     =     1-2317  E 

Thus  a  solution  of  sodium  hydroxide  of  specific  gravity  1-206 
containing  13-3  per  cent,  of  NaOH  will  contain  13-3  x  0-775  = 
10-3  per  cent,  of  Na2O  ;  one  containing  21'5  per  cent,  of  K2CO3 
is  equivalent  to  another  containing  21*5  x  0*8119  —  17*46  per 
cent,  of  KOH  *  and  so  on. 


426  OILS,    FATS,    WAXES,    ETC. 

The  following  analogous  formulae  may  be  used  to  calculate  the 
quantity  of  soda  equivalent  to  a  given  weight  of  potash  or  vice 
versd.  Let  H  be  a  given  quantity  of  sodium  carbonate  and  I 
the  potassium  carbonate  equivalent  thereto  ;  similarly  let  J  be 
a  given  amount  of  sodium  hydroxide  and  K  the  potassium 
hydroxide  corresponding  therewith ;  and  let  L  be  a  given  quantity 
of  Na^O,  and  M  the  K2O  equivalent  thereto.  Then — 

1^   l     =     °'767°  I 
Carbonates,         .     . 

H     -     1-3038  H 


J      =        -Jf.-     K    =     0-7130  J 

GO  1 

Hydroxides,  .     .     . 

'      K  ^     J  1-4025  K 

L  -^r    M  0-6582  L 

Anhydrous  oxides, 

M  *^i    L     =     1-5194  M 

Thus  10  per  cent,  of  K2O  in  a  given  soap  is  equivalent  to 
10  x  0-6582  =  6-582  per  cent,  of  Na2O.  A  liquor  containing 
8  per  cent,  of  NaOH  is  of  the  same  alkaline  strength  as  one 
containing  8  x  1-4025  =  11-22  per  cent,  of  KOH  ;  and  so  on. 


CHAPTER  XIX. 
SOAPMAKING    PLANT. 

HEATING   APPLIANCES. 

THE  plant  and  appliances  requisite  for  the  manufacture  of  soap 
vary  somewhat  according  to  the  nature  of  the  process  used  and 
the  scale  on  which  it  is  conducted.  Formerly  the  vessels  (usually 
known  as  "  pans,"  "  coppers,"  or  "  kettles  ")  in  which  the  boiling 
operations  were  conducted  were  uniformly  mounted  over  free 
fires,  so  that  the  flame  produced  by  the  combustion  of  fuel  in  a 
fireplace  placed  beneath  the  pan  was  made  to  play  over  the  rest 
of  the  bottom  and  part  of  the  sides  of  the  pan  by  means  of  a 
suitably  arranged  circular  flue  provided  with  a  damper  for  the 
purpose  of  regulating  the  draught.  Several  coppers  were  usually 
mounted  side  by  side,  so  that  the  products  of  combustion  of  their 
respective  fires  passed  into  the  same  common  tunnel  or  flue  lead- 


FREE-FIRED    SOAP    PANS. 


427 


ing  to  the  main  chimney  of  the  works.  At  the  present  day  this 
system  of  free  firing  is  comparatively  seldom  applied  in  the 
larger  soap  factories,  the  coppers  being  more  frequently  heated 
by  steam  supplied  from  a  special  boiler,  and  in  some  cases  super- 
heated before  use.  Fig.  108  gives  a  general  idea  of  the  disposi- 


Fig.  108. 

tion    of  the    arrangements    adopted   for   a  free-fired  pan.     The 
pan,   J,   is   mounted    in  masonry  over  the    fireplace,  B,  placed 
centrally  beneath  it,  a  nearly  circular  flue,  E,  carrying  the  flame 
round  the  lower  part  of  the  pan  to  the  chimney,  F ;  C  is  the 
grate  or  range  of  firebars  supporting  the  fuel,  and  D  the  ashpit. 
The  leys,  &c.,  are  drawn  off 
as  required  by  the  tube  and 
draw-off  cock,   K  ;    the  level 
of    the    flooring    or     staging 
round  the  pan,  A,  A,  is  raised 
so  that  the    top  of  the    pan 
projects  upwards  some  3  feet. 
Fig.  109   represents  a  cast 
iron  pan  of  slightly  different 
type,  A,  also  mounted  so  as 
to  be  heated   by  free  firing  ; 
in  this  case  the  fireplace,  B, 
is    not    placed    centrally    be- 
neath the  pan,  but  somewhat  Fig.  109. 
in    front   of    it,    the    heating 

being    chiefly    effected    by   the    hot    air   chamber,    E,   in  which 
the   products   of    combustion    circulate    round   and    under   the 


428 


OILS,    FATS,    WAXES,    ETC. 


base  of  the  pan  before  passing  away  to  the  flue.     C,  firebars  ; 
D,  ashpit. 

In  the  case  of  modern  steam  heated  pans,  the  steam  is  applied 
in  various  ways.  Heating  by  "  wet "  steam  consists  in  blowing 
steam  at  a  sufficient  pressure  direct  into  the  mass  to  be  heated, 
so  that  the  water  produced  by  the  condensation  of  the  steam 
dilutes  the  whole  until  the  temperature  rises  so  high  that  the 
steam  simply  blows  through  without  becoming  materially  con- 
densed ;  for  most  general  boiling  purposes  a  wet  steam  coil  is 
thus  used,  consisting  of  an  iron  pipe  descending  to  near  the 
bottom  of  the  copper  arid  terminating  in  a  ring  perforated  with 
holes  through  which  the  steam  issues,  bubbling  up  through  the 
mass  and  producing  a  very  effective  agitation  and  intermixture 
of  the  contents  when  the  heat  is  sufficient  to  cause  the  steam  to 
blow  through.  In  some  districts  this  wet  steam  coil  is  accord- 
ingly spoken  of  as  the  "blowpipe;"  superheated  steam  is  some- 


Fig.  11U. 

times  employed  instead  of  steam  supplied  direct  from  the  boiler, 
so  as  to  diminish  the  amount  of  water  condensation. 

Heating  by  "  dry "  steam  consists  in  causing  steam  (either 
direct  from  a  high  pressure  boiler,  or  preferably  for  many  pur- 
poses, superheated)  to  circulate  through  a  sort  of  spiral  tube  or 
coil  arranged  in  the  lower  part  of  the  copper ;  the  water  con- 
densed in  the  coil  accordingly  does  not  pass  into  the  heated 
mass,  thereby  diluting  the  leys,  &c.,  but  is  blown  off  along  with 
the  exit  steam.  Dry  steam  is  also  sometimes  employed  to  heat 
an  external  jacket  usually  only  surrounding  the  lower  part  of 
the  pan;  Fig.  110  indicates  the  kind  of  arrangement — C,  steam 
supply  pipe  ;  D,  pipe  and  cock  for  drawing  off  condensed  water ; 
A,  copper;  B,  steam  jacket  at  base  of  copper  ;  E,  draw  off  pipe 
from  copper.  A  mechanical  stirring  arrangement  to  keep  the 
mass  agitated  is  conveniently  added. 

In  order  to  facilitate  intermixture  of  materials  in  the  pan 
whilst  heating  up  by  dry  steam  an  appliance  known  as  "  Morfit's 
steam  twirl "  is  much  used.  Fig.  Ill  represents  one  form  of 
arrangement  applied  to  a  comparatively  shallow  copper  sup- 


MORFIT'S  STEAM  TWIRL. 


429 


ported  by  a  wooden  frame  work,  A  A,  B  B.  The  steam  from  the 
steam  pipe,  G,  passes  into  a  hollow  spindle,  D  D  E,  the  central 
part  of  which  is 
blocked,  so  that  the 
steam  is  obliged  to 
pass  through  the  con- 
voluted tubes,  K  K, 
KK,  braced  together 
by  cross  pieces, 
HHH,  which  also 
serve  as  stirring 
vanes.  By  means 
of  the  bevel  wheels, 
L  L,  worked  from 
the  shaft  and  pulley, 
M  N,  the  twirl  is  set 
in  motion,  so  that 
the  contents  of  the 
pan  are  thoroughly 
agitated  whilst  being 
heated  up.  The  con- 
densed water  blows 
off  at  E  with  the 
surplus  steam,  whilst 
C  is  the  discharge 
cock  of  the  pan. 
The  same  appliance 
can  also  be  used  with 
wet  steam,  the  con- 
voluted tubes  being 
pierced  with  holes 
so  as  to  allow  part  of  the  steam  to  escape  directly  into  the  mass 
of  material. 

Soap  Coppers. — Formerly  the  vessels  in  which  soap  and  leys 
were  boiled  together  were  made  of  various  kinds  of  materials ; 
sometimes  of  masonry,  iron  bottoms  being  provided  for  heating 
by  free  fire  ;  sometimes  of  cast  iron,  like  the  pan  represented  in 
Fig.  109,  or  of  wrought  iron  plates  ri vetted  together  subse- 
quently, or  of  wooden  staves  strongly  bound  together  like 
enormous  tubs,  wet  steam  being  the  source  of  heat. 

These  forms,  however,  were  mostly  adapted  only  for  use  with 
quantities  of  material  small  in  comparison  with  those  in  use  at 
the  present  day,  when  charges  of  30  to  40  tons  and  upwards  of 
fatty  matters  are  not  uncommon ;  a  more  recent  form  of  soap 
kettle  is  a  cylindrical  or  conical  cauldron  with  somewhat  rounded 
apex,  placed  base  upwards,  constructed  of  boiler  plates  well 
rivetted  together,  as  indicated  in  Fig.  112;  the  degree  of  slope 
of  the  sides  (regulating  the  ratio  between  the  top  and  bottom 


430 


OILS,    FATS,    WAXES,    ETC. 


diameters)  and  the  relation  between  the  depth  and  maximum 
diameters  vary  somewhat  in  different  countries — e.g.,  soap  kettles 


Fist.  113. 


SOAP    COPPERS. 


431 


of  this  pattern  in  America  are  generally  from  two  to  three  times 
as  deep  as  they  are  wide,  sometimes  filling  a  building  of  two  or 
three  stories;  whilst  in  Britain  the  depth  rarely  exceeds  once 
and  half  times  the  diameter,  still  shallower  pans  being  often  used. 
A  copper  15  feet  diameter  and  15  feet  deep  will  turn  out  20  to 


Fig.  114. 

30  tons  of  soap,  a  usual  rule  being  to  allow  6  cubic  feet  capacity 
(about  37-5  gallons)  for  each  100  Ibs.  weight  of  fatty  matters 
treated,  or  about  135  cubic  feet  (nearly  850  gallons) per  ton;  so  that 
a  copper  holding  some  2,500  cubic  feet  (upwards  of  15,000  gallons) 
will  suffice  for  about  18  tons  of  fatty  matters  yielding  25  to  30 


432 


OILS,    PATS,    WAXES,    ETC. 


tons  of  soap  according  to  the  amount  of  water  contained  therein. 
Fig.  113  represents  "  Morfit's  Steam  Series,"  a  set  of  three  coppers 
supplied  with  both  sets  of  steam  coils  (wet  and  dry).  B  B  is  the 
steam  main  supplied  from  the  boiler,  A ;  K  is  the  wet  steam 
pipe ;  and  D  F  G  the  dry  steam  coil.  The  lowest  part  of  the 


Fig.  115. 

copper  is  usually  provided  with  a  narrower  basin  or  hat-shaped 
downward  prolongation  for  the  more  easy  collection  and  separa- 
tion of  watery  leys,  &c. ;  in  the  figure  it  is  represented  as  con- 
nected with  a  draw  off  tube,  H,  provided  with  a  cock,  J.  F  F  F 
represent  "  Curbs  "  (infra)  of  different  shapes  to  prevent  boiling 
over. 


CURB    AND    FAN.  433 

Figs.  114  and  115  represent  a  modern  form  of  pan  for  heat- 
ing with  either  dry  or  wet  steam  as  required,  constructed  by 
Messrs.  W.  Neill  &  Son,  of  St.  Helens,  Lancashire.  This  is  a 
square  tank  made  of  steel  plates  rivetted  together,  with  rounded 
corners  and  dished  bottom,  the  square  form  being  preferably 
employed  as  taking  up  less  room  than  the  circular  shape  requisite 
in  the  case  of  free-fired  coppers  provided  with  flues  running 
round  the  lower  part  of  the  pan  (Fig.  108).  The  pan  is  fitted 
with  wet  and  dry  steam  coils,  and  a  cock  at  the  bottom  for  run- 
ning off  spent  leys.  A  "skimmer  pipe"  is  provided,  working 
on  a  swivel  joint,  and  capable  of  being  adjusted  at  any  required 
height  by  a  supporting  chain ;  as  represented  in  the  figure,  the 
fluid  soap  is  run  off  by  gravity  through  a  down  pipe;  but  if 
required  a  pump  can  be  connected  at  the  elbow  instead,  a  cock 
being  affixed  to  shut  off  connection  when  the  pump  is  not  at 
work. 

An  airblast  has  been  employed  by  Dunn  for  the  purpose  of 
intermixing  the  ley  and  fatty  matters  during  the  preliminary 
stage  of  "  killing  the  goods,"  and  the  subsequent  operations  when 
free-fired  pans  are  employed,  whereby  tumultuous  boiling  is 
largely  avoided ;  the  air  was  introduced  by  a  "  blowpipe " 
arranged  in  much  the  same  way  as  the  more  modern  wet 
t  steam  coil.  The  process  was  said  to  answer  well ;  but  has 
nowadays  fallen  into  disuse  through  the  substitution  of  steam- 
heate'oHpans  for  free-fired  kettles. 

Cui*9  and  Fan. — With  certain  kinds  of  materials,  and  parti- 
1/cularly  at  certain  stages  of  the  operation,  tumultuous  boiling  up 
or  "bumping,"  and  vigorous  frothing  are  apt  to  occur,  more 
especially  when  oleine  soap  is  made  by  the  direct  addition  of  hot 
carbonated  leys  to  free  oleic  acid  (red  oils,  vide  Chap,  xx.),  and 
during  the  -"'graining "  or  "cutting"  of  boiled  soaps — i.e.,  the 
throwing  them  out  of  watery  solutions  by  addition  of  salt  (vide 
Chap,  xx.)  Two  appliances  are  of  considerable  utility  in  diminish- 
ing the  chance  of  loss  by  boiling  over  under  such  conditions.  One, 
known  as  the  "  curb,"  is  simply  a  temporary  expansion  of  the 
upper  part  of  the  pan,  consisting  of  a  conical,  circular,  or  barrel- 
shaped  addition  bolted  on  so  as  virtually  to  amplify  considerably 
the  dimensions  of  the  copper  at  the  top.  Fig.  113  represents 
a  cone,  F,  of  wooden  staves,  hooped  together  with  iron,  applied 
to  one  kettle,  and  a  barrel -shaped  analogous  curb  applied  to 
another. 

The  other  arrangement  is  termed  a  "fan,"  Fig.  116,  and 
consists  of  a  sort  of  pair  of  paddle-wheels  suspended  in  the  pan 
at  such  a  depth  below  the  surface  as  may  be  requisite,  so  that  as 
the  paddles  revolve  the  froth  is  broken  by  them  and  prevented 
from  rising  up  and  boiling  over.  Motion  is  communicated  to  the 
paddles  by  means  of  a  vertical  shaft  with  bevel  wheels  at  top 
and  bottom,  the  shaft  being  telescopic  so  as  to  admit  of  being 

28 


434 


OILS,    FATS,    WAXES,    ETC. 


drawn  up  and  down  to  adjust  the  level  of  the  paddles  as  re- 
quired j  it  rotates  within  a  tube  carrying  a  Y-shaped  frame  at 

each  end,  the  whole 
being  suspended  from 
the  upper  horizontal 
shaft,  by  means  of 
wrhich  motion  is  com- 
municated to  the  ver- 
tical shaft  through  the 
bevel  wheels,  whilst 
the  lower  Y  serves  as 
bearings  for  the  axle  of 
the  paddles. 

Soap  Fra-mes. — 
When  the  operation  of 
soapmaking  is  finished, 
and  the  spent  leys 
(when  such  are  present) 
removed  by  subsidence, 
etc.,  the  resulting  soap 
usually  forms  a  hot 
semifluid  or  pasty  mass 
which,  on  cooling,  more 
or  less  thoroughly 
solidifies  to  a  soft  solid 
substance.  In  order 
to  facilitate  the  opera- 
tion of  cutting  up  the 
mass  into  bars  and 
tablets  for  sale  without 
waste,  the  hot  soap  is 
run  by  gravitation,  or 
ladled,  or  pumped  out 
of  the  copper  in  which 
it  is  made  into  "frames,"  in  which  it  is  allowed  to  solidify.  The 
pumps  used  for  this  purpose  are  generally  of  somewhat  different 
construction  from  the  ordinary  suction  pump  used  for  wells,  &c. 
Fig.  117  represents  a  rotary  soap  pump  as  constructed  by  Hersee 
Brothers  of  Boston.  Instead  of  pumping  out  the  soap,  it  may 
more  conveniently  be  run  off  by  gravity  by  means  of  the  adjust- 
able "skimmer  pipe"  shown  in  Fig.  114,  the  frames  being 
arranged  so  that  their  tops  are  at  a  level  below  the  elbow  joint 
of  the  pipe. 

A  method  sometimes  used  for  emptying  kettles  and  raising 
their  contents  to  a  higher  elevation  was  introduced  by  Gossage, 
consisting  of  the  application  of  a  cover  fitting  airtight,  and  then 
forcing  in  compressed  air,  so  as  to  press  the  semifluid  soap  up  a 
pipe  the  lower  end  of  which  dips  into  the  kettle  to  the  required 


Fig.  116. 


SOAP    FRAMES. 


435 


depth;  the  whole  arrangement  working  on  the  principle  of  the 
"  acid  egg  "  used  in  vitriol  factories  for  elevating  the  acid  without 
employing  ordinary  pumps. 


Fig.  119. 

The  size  of  the  frames  employed  and  the  material  of  which 
they  are  composed  vary,  wood  being  preferable  when  slow  cooling 


436 


OILS,    FAT?,    WAXES,    ETC. 


I 


Fig.  120. 


SLABBING    AND    BARBING. 


437 


is  essential,  but  iron  being  considerably  more  convenient  in  other 
cases.     For  toilet  soaps,  frames  holding  1  cwt.  or  less  are  often 


Fig.  121. 

employed ;  for  scouring  soaps  much  larger  ones,  furnishing  ulti- 
mately a  block  of  cooled  soap  weighing  8,  10,  15,  or  more  cwts.* 
Fig.  118  indicates  the  way  in  which  a  wooden  frame  may  be 
built  up  of  a  set  of  squares  pegged  together 
and  superposed  on  a  bottom  board.  Fig.  119 
represents  a  frame  constructed  of  galvanised 
iron  plates  where  the  ends  fit  into  grooves 
formed  by  turning  round  the  corners  of  the 
side  plates,  or  fitting  pieces  of  angle  iron 
thereto;  the  side  and  end  plates  are  similarly 
fitted  to  the  iron  bottom,  and  the  whole  kept 
together  by  two  transverse  rods  at  the  top 
fitted  with  screws  and  nuts.  Fig.  120  repre- 
sents an  improved  form  of  steel  soap  frame, 
mounted  on  four  wheels,  and  held  together 
by  cap  fastenings. 

When  the  block  of  soap  has  .completely 
cooled  down  and  set  solid,  the  frame  is  taken 
to  pieces  and  the  block  cut  into  slabs,  which 
are  then  transversely  cut  up  into  bars. 
When  this  is  done  by  hand  the  block  is  cut 
in  a  very  simple  fashion  by  simply  pulling  a 
looped  wire  (Figs.  121  and  122)  through  it 
horizontally  so  as  to  cut  through  the  mass 
along  a  series  of  parallel  lines  previously 


Fig.  122. 


marked  011  the  outside  by  means  of  a  scribe  (Fig.  123).  Slabbing 
and  barring  machines  of  various  patterns  are  frequently  employed 
for  this  purpose  (Fig.  124).  When  it  is  requisite  that  the  soap 

*  Formerly,  the  size  of  the  soap  frames  was  fixed  by  excise  laws  and  regula 
tions,  and  required  to  be  45  inches  long  by  15  wide,  inside  measurement, 
and  not  less  than  45  inches  deep  (usually  made  50  to  60  inches  deep) ;  so  as  to 
hold  some  15  to  20  cubic  feet,  or  about  9  to  11  cwts.  of  soap,  Although  no 
longer  compulsory,  this  size  is  still  largely  employed. 


438  OILS,    FATS,    WAXES,    ETC. 

should  cool  very  slowly  in  the  frame  (e.g.,  in.  order  to  promote 
saponification  in  making  cold  process  soap  —  p.  457 ;  or  to 
facilitate  mottling — Chap,  xx.)  the  sides  of  the  frame 
are  sometimes  padded  to  keep  in  the  heat  (Fig.  125). 
The  bars  of  soap  into  which  a  block  is  cut  gener- 
ally weigh  about  3  Ibs.  ;  they  are  usually  stacked  in 
a  hollow  pile  to  dry  the  outside  slightly  so  as  to  case- 
harden  them,  as  it  were,  or  else  are  stored  on  lattice 
work  shelves  in  an  open  rack  allowing  free  access  of 
Fig  ^123.  a^r-  With  very  moist  soaps,  this  drying  action  is  apt 
to  go  too  far,  warping  the  bar  out  of  shape,  besides 
causing  it  to  lose  weight  largely  ;  accordingly  such  bars  are 
often  "pickled"  by  immersion  in  brine,  which  slightly  indurates 
the  outside.  Of  late  years  a  considerable  demand  has  sprung 
up  for  1  Ib.  blocks  instead  of  3  Ib.  bars  ;  such  blocks  are  gener- 
ally cut  to  size  and  shape  and  then  stamped  like  toilet  cakes  in 
similar  machines  but  of  larger  size  (p.  444).  Often  the  block  is 
grooved  in  the  centre,  so  that  it  can  be  readily  broken  into  two ; 
or  three  grooves  are  stamped  at  equidistant  intervals  enabling 
four  4  oz.  blocks  to  be  obtained. 

Crutching  Machines. — Formerly,  when  it  was  requisite  to 
stir  up  soap  containing  excess  of  wrater  in  the  cooling  frames  to 
prevent  its  separating  into  two  liquids,  a  peculiar  hand  worked 
agitator  termed  a  "  crutch  "  was  largely  used,  consisting  of  a 
square  piece  of  board  with  a  handle  attached  to  the  centre  of 
the  square  perpendicular  to  its  plane  (Fig.  126) ;  by  plunging  this 
into  the  pasty  mass,  and  working  it  up  and  down,  a  sufficiently 
efficient  mixing  was  brought  about.  Such  implements  are  still 
in  use,  especially  for  small-scale  operations,  but  have  been  largely 
superseded  by  mixing  machines,  the  operation  of  agitation  by 
their  means  being  still  spoken  of  as  "  crutching."  For  inter- 
mixing silicate  or  resinate  of  soda  solution  with  boiled  soaps  in 
large  quantities  at  a  time,  or  for  otherwise  working  in  saline 
solutions  to  dilute  and  harden  the  soap  or  improve  its  detergent 
qualities,  or  "  filling  "  of  various  kinds,  as  well  as  for  preventing 
separation  of  watery  fluid  from  the  mass,  such  machines  are 
largely  employed.  Various  forms  are  employed — Fig  127  repre- 
sents a  horizontal  cylindrical  form,  with  a  rotating  internal  axle 
provided  with  projecting  vanes  for  stirring  up  the  contents  ;  when 
required  for  rapid  cooling  or  heating  an  outer  jacket  is  applied 
into  which  water  or  steam  can  be  admitted  as  required 
(Fig.  128). 

Figs.  129  and  130  represent  a  series  of  three  crutching  pans 
arranged  so  as  to  be  worked  from  the  same  shaft.  By  means 
of  the  clutches  indicated,  any  one  of  the  three  can  be  set  in 
motion  or  stopped  as  required :  the  stirring  vanes  are  here 
horizontal,  projecting  from  a  vertical  axle,  similar  fixed  vanes 
being  arranged  internally  so  as  to  prevent  the  liquid  mass  from 


CRUTCHING    MACHINES. 


439 


simply  swinging  round  and  round  without  being  broken  up  and 
intermixed. 

In  another  form  of  mixing   machine  two  sets  of  vanes  are 


provided,  moved  in  opposite  directions  by  means  of  bevel 
wheels,  one  axle  being  hollow  and  the  other  working  inside  it 
like  the  axles  carrying  the  two  hands  of  a  watch.  The  vanes 
slope  at  an  angle  of  45°,  so  that  the  material  is  continually 


440 


OILS,    FATS,    WAXES,    ETC. 


lifted  and  the  different  layers  intermixed,   the  general   action 
resembling  that  of  an  ordinary  eggwhisk.     Large  steam  driven 


Fig.  127. 

sizes  are  very  effective ;  but  if  worked  too  rapidly  the  mass  is 
apt  to  become  frothy.  For  very  stiff  soap,  an  archimedean 
screw,  working  inside  a  wider  cylinder,  answers  very  well. 


TOILET    SOAP    MACHINERY. 


441 


Toilet  Soap  Machinery.  —  In  the  manufacture  of  various 
kinds  of  toilet  soaps,  several  special  kinds  of  appliances  are  used 
varying  in  their  nature  with  the  process  adopted.  When 
"  stock "  soaps  prepared  on  the  large  scale  are  "  remelted," 
for  the  purpose  of  blending  together  different  kinds,  with  the 
addition  of  colouring  or  scenting  materials,  «fcc.,  a  steam  jacketted 
pan  is  generally  preferred,  somewhat  after  the  fashion  of  Fig.  110 ; 
as  the  soap  (previously  cut  up  into  small  lumps)  melts,  it  is 
mixed  together  either  by  hand  crutching  (supra)  or  by  means 


Fig.  128. 

of  some  form  of  agitator;  too  rapid  a  movement  must  not 
be  communicated  to  this,  otherwise  air  bubbles  are  stirred 
in  and  the  soap  becomes  more  or  less  frothy,  forming  a  spongy 
mass  when  solid.*  Figs.  131  and  132  represent  a  very  effec- 
tive form  of  remelter  constructed  by  W.  Neill  &  Son,  where 
the  heating  action  of  the  outer  steam  jacket  is  greatly  amplified 
by  means  of  the  internal  cross  steam  pipes ;  the  pieces  of 
soap  are  continually  brought  in  contact  with  these  by  the 
motion  of  the  agitating  arms,  and  as  a  large  heating  surface 
is  thus  brought  into  play  the  remelting  proceeds  rapidly. 
When  finished,  after  intermixture  of  the  various  ingredients 

"Floating"  soaps  are  purposely  prepared  in  this  way,  enough  air 
bubbles  bein^  worked  in  to  enable  the  tablet  to  float  in  water,  even  after 
compression  in  the  stamping  press. 


442 


OILS,    FATS,    WAXES,    ETC. 


REMELTINC    PANS. 


443 


Fig.  132. 


444 


OILS,    FATS,    WAXES,    ETC. 


intended  to  render  the  soap  emollient,  to  scent  it,  or  otherwise 
to  improve  its  qualities,  the  fluid  mass  is  cast  in  small  frames  so 
as  to  form  blocks  of  J  cwt.  or  upwards,  according  to  circum- 
stances ;  usually  these  are  made  of  iron  plates  bolted  together,  as 
indicated  in  Fig.  119,  so  as  to  cool  quickly  and  avoid  as  far  as 
possible  loss  of  volatile  scenting  materials,  and  the  injurious 
effect  of  heat  thereon.  The  blocks  when  cold  are  then  slabbed 
and  barred  by  hand  or  machine,  and  the  bars  cut  into  short 
lengths,  each  of  which  is  then  stamped  into  tablet  form  by  some 
form  of  press  acting  on  the  principle  of  a  coining  press,  where 


Fig.  133. 

both  sides  of  the  coin  or  medal  are  embossed  at  once,  a  ring  or 
collar  being  adjusted  round  the  medal  so  as  to  prevent  its  swell- 
ing out  sideways  under  the  pressure.  A  large  variety  of  tablet 
stamping  machines  are  in  use ;  some  are  worked  by  hand,  the 
upper  die  and  collar  being  attached  to  a  rod  or  plunger  worked 
by  a  lever  provided  with  a  balance  weight,  so  that  by  forcibly 
pulling  down  the  lever  the  die  descends  and  stamps  the  tablet. 
Fig.  133  represents  a  machine  of  this  description,  and  Figs.  134 
and  135  a  steam  stamping  machine,  where  the  impact  of  the  die 
is  given  by  letting  steam  into  the  cylinder  by  means  of  the  valve 


STAMPING    MACHINES. 


445 


handle,  so  that  the  piston  suddenly  rises,  and  consequently 
depresses  the  plunger  to  which  the  die  is  attached  on  the 
opposite  side  of  the  axis  of  motion.  In  another  form  of  machine 


Fig.  134. 


Fig.  135. 

the  requisite  impact  is  given  by  raising  the  upper  die  to  which 
a  considerable  weight  is  attached,  and  then  letting  it  fall,  pile- 
driver  fashion. 

In  the  case  of  transparent  toilet  soaps  made  by  the  spirit 
process  (Chap.  xx.\  the  pan  in  which  the  solution  of  the  soap  in 


446  OILS,    FATS,    WAXES,    ETC. 

spirit  is  effected  is  connected  with  a  still  head  and  worm,  so  that 
the  alcoholic  vapours  evolved  are  condensed  and  regained.  With 
soaps  of  this  class,  the  liquid  soap  left  when  most  of  the  spirit  is 
distilled  off  is  run  into  frames,  so  as  to  gelatinise  and  solidify, 
and  is  then  cut  up  into  tablet  blanks,  which  are  exposed  to  the 
air  for  a  considerable  length  of  time  (several  weeks  or  even 
months)  in  a  warm  room,  so  as  to  consolidate  them  by  gradual 
evaporation  of  remaining  alcohol,  etc.,  otherwise  they  would  be 
too  soft  to  keep  their  shape  properly.  Moreover,  when  freshly 


Fig.  136. 

•prepared  the  mass  is  often  "muddy;"  but  on  keeping,  it  gradually 
becomes  transparent  and  clear. 

Milled  Soaps. — Much  more  elaborate  machinery  is  requisite 
for  the  manufacture  of  "  milled  "  soaps.  The  bars  of  stock  soap 
are  first  "  stripped  " — i.e.,  cut  into  slices  or  chips  by  a  slicing 
machine,  actuated  like  a  rotary  plane  or  vegetable  cutter. 
Fig.  136  represents  Rutschmann's  stripping  machine.  The  chips 
are  dried  in  a  warm  air  chamber  until  only  a  few  per  cents, 
of  moisture  are  retained,  and  are  then  ground  between  successive 


MILLED    SOAPS. 


447 


pairs  of  heavy  horizontal  rollers,  so  arranged  that  the  soap  first 
passes  between  No.  1  and  No.  2  rollers,  then  between  No.  2  and 
No.  3,  and  so  on,  somewhat  as  in  the  case  of  seed  crushing  for 
oil  extraction  (p.  218).  Each  roller  is  made  to  revolve  somewhat 
faster  than  the  previous  one,  so  that  the  soap  slices  are  not 
merely  crushed  in  passing  through,  but  are  also  rubbed ;  the 
soap  always  adheres  to  the  more  quickly  moving  roller,  so  that  it 
passes  onwards  automatically.  By  means  of  "  doctors "  or 
scrapers,  it  is  detached  from  the  last  roller  in  strips  or  ribbons, 
which  are  returned  to  the  front  of  the  machine  and  passed 


Fig.  137. 

through  again  and  again.     Fig.  137  represents  a  form  of  mill  for 
the  purpose. 

In  order  to  facilitate  the  preliminary  drying  of  the  stock  soapr 
A.  &  E.  des  Cressonnieres*  use  a  series  of  rollers  arranged 
vertically  one  above  another  in  an  enclosed  space  heated  by 
steam  or  hot  air,  &c.  Soap  in  a  just  fluid  state  from  the  remelter, 
&c.,  passes  in  a  flat  stream  from  a  hopper  on  to  the  top  roller,  the 
contact  with  which  partly  solidifies  it;  the  resulting  semisolid 
sheet  passes  alternately  from  right  to  left,  and  vice  versd,  between 
each  successive  pair  of  rollers,  as  in  the  mill  itself,  finally 
emerging  at  the  bottom  in  the  form  of  a  solid  sheet,  which  is 
separated  by  an  automatic  cutter  into  strips.  The  temperature 

*  English  patent,  No.  2,446,  1890. 


448 


OILS,    FATS,    WAXES,    ETC. 


of  the  chamber  and  the  rate  of  soap  supply  are  so  adjusted  that 
the  strips  are  sufficiently  dried  by  the  time  they  emerge. 

When  the  various  stock  soaps  used,  colouring  matters, 
perfumes,  unguents  (lanolin,  vaseline,  spermaceti,  tfec.,  as  re- 
quired in  special  cases),  or  medicinal  agents,  are  thoroughly 
incorporated  together  in  the  mill,  the  whole  mass  (if  not  over- 
dried)  becomes  compara- 
tively soft  and  plastic, 
much  as  partially  dried 
putty  is  softened  by  roll- 
ing and  working  it  in  the 
hand.  When  thoroughly 
intermixed,  the  ribbons 
stripped  off  the  last  roller 
are  strongly  compressed 
together ;  in  one  class  of 
machine  by  filling  them 
into  a  barrel  or  cylinder 
provided  with  a  conical 
end  terminating  in  a 
nozzle,  and  forcing  the 
mass  outwards  by  means 
of  a  piston  worked  by  a 
screw  or  by  hydraulic 
power :  the  plastic  rib- 
bons are  thus  "  squirted  " 
outwards  through  the 
nozzle  as  a  continuous  bar,  which  is  then  cut  into  short  lengths  and 
stamped  into  tablets.  In  another  class  of  "plotting  machine,"* 
the  ribbons  are  made  to  fall  from  a  hopper  into  the  grooves  of  a 
large  conical  archimedean  screw  working  in  a  funnel  shaped 
barrel,  terminating  in  a  nozzle  of  appropriate  size  ;  as  the  screw 
revolves  the  soap  is  gradually  propelled  onwards  towards  the 
nozzle,  and  on  account  of  the  diminishing  diameter  of  the  worm, 
becomes  strongly  compressed  together,  so  as  finally  to  issue  from 
the  nozzle  as  a  firm  solid  bar,  which  is  then  cut  up  and 
stamped  as  before.  Fig.  138  represents  Beyer's  plotting  machine 
working  on  this  principle. 

Cylindrical  and  spherical  soap  tablets  and  wash  balls  are  some- 
times prepared;  these  are  usually  stamped  into  approximately  the 
required  shape  by  means  of  suitable  presses,  or  by  hand,  and  when 
sufficiently  dry,  finished  by  turning  and  polishing  in  a  kind  of  lathe. 
In  order  to  give  a  polished  surface  to  soap  tablets,  a  method 
frequently  employed  is  to  expose  them  to  wet  steam  for  a  few 
seconds,  which  glazes  the  exterior.  More  expensive  varieties 
are  sometimes  polished  by  hand,  using  a  cloth  dipped  in 
alcohol,  &c. 

*  From  the  French  term,  " pelotage,"  applied  to  this  squirting  process. 


SOAPMAKING    PROCESSES.  449 


CHAPTER    XX. 
MANUFACTURE    OF    SOAP. 

As  compared  with  metallurgical  and  textile  industries  the  art  of 
soapmaking  is  not  possessed  of  any  claims  to  great  antiquity  ; 
the  ancients  were  acquainted  with  the  detergent  power  of  wood 
ashes  (vegetable  alkali)  and  probably  also  with  that  of  mineral 
soda  or  natron*  but  do  not  appear  to  have  known  anything  of 
the  products  of  the  action  of  these  substances  on  oleaginous 
materials,  no  mention  of  any  such  compounds  being  to  be  found 
in  Homer  or  other  early  Grecian  authors ;  whilst  the  Hebrew 
term  borith  f  used  by  the  prophets  Jeremiah  and  Malachi, 
although  translated  "  soap,"  appears  to  have  simply  meant  ivood- 
ash  alkali. 

Pliny  the  elder,  however,  in  the  first  century  A.D.  described 
a  sort  of  imperfect  soft  soap  made  from  goat's  tallow  and  the 
alkali  from  beech  wood  ash ;  and  also  a  harder  variety  (possibly 
got  by  the  action  of  salt  on  the  former,  producing  soda  soap) ; 
and  another  writer  in  the  second  century  in  a  work  entitled 
De  Simplicitus  Medicaminibus  refers  to  a  softer  "  German " 
variety  of  soap  (probably  chiefly  made  from  the  ashes  of  land 
plants)  and  a  harder  "  Gallic  "  form  (probably  derived  from  sea- 
weed ash).  Later  still,  soapmaking  appears  to  have  been  some- 
what more  extensively  practised,  as  the  remains  of  a  soap  factory 
have  been  found  at  Pompeii. 

Soapmaking  Processes. — The  variations  in  the  different 
methods  by  which  soaps  are  prepared  on  the  manufacturing 
scale  are  somewhat  numerous,  but  all  may  be  conveniently 
classified  under  one  or  other  of  the  three  following  heads,  so  far 
as  the  essential  parts  of  the  soap  producing  processes  are  concerned. 
In  many  cases,  however,  various  subsequent  operations  are  gone 
through  before  the  goods  are  finally  ready  for  the  market,  con- 
sisting either  of  mechanical  cutting  and  shaping  operations,  such 
as  casting  into  blocks,  cutting  these  up  into  slabs,  bars,  and 
tablets,  and  stamping  the  latter  into  shape  in  appropriate  presses ; 
or  of  the  addition  of  other  substances  to  the  soap  before  cooling 

*  Proverbs  xxv.  20.— "As  vinegar  upon  nitre  [or  soda,  marginal  note, 
Revised  Version],  so  is  he  that  singeth  songs  to  an  heavy  heart."  The 
frothy  uon-perinanent  effervescence  due  to  the  action  of  the  acid  on  natron 
is  doubtless  what  is  here  alluded  to  ;  acetic  acid  and  nitre  (potassium 
nitrate)  having  no  mutual  action  whatever. 

t  Jeremiah  ii.  22. — "Wash  thee  with  lye,  and  take  thee  much  soap." 
Malachi  iii.  2.  — "Like  a  refiner's  fire  and  like  fuller's  soap." 

29 


450  OILS,    FATS,    WAXES,    ETC. 

or  solidifying,  so  as  to  increase  its  detergent  properties ;  or  to 
give  it  special  qualities  (e.g.,  disinfecting  action);  or  to  harden  it, 
so  as  to  enable  more  water  or  other  weight-giving  "filling"  to 
be  added  without  rendering  it  too  soft  for  ordinary  scouring 
purposes,  £c. 

I.  Direct    Neutralisation    Processes. — Where    free   fatty 
acids  and  alkalies  are  brought  together  and  converted  into  soaps 
by  directly  neutralising  one  another,  with  or  without  evolution 
of  carbonic  acid  gas  according  as  carbonated  or  caustic  alkalies 
are  employed.     Obviously  no  glycerol  is  produced  in  the  formation 
of  soaps  of  this  kind. 

The  free  fatty  acids  thus  employed  are  practically  almost  con- 
fined to  the  "red  oils'"  of  the  candlemaker  (p.  386)— i.e.,  the 
liquid  fatty  acids  expressed  from  the  mixed  products  of  saponi- 
fication  leaving  behind  the  solid  acids  (commercial  "  stearine  "). 
Certain  distilled  and  recovered  greases  (such  as  Yorkshire  grease 
from  the  suds  of  wool  scouring,  &c.,  Chap.  XH.)  are  of  similar 
character,  and  are  sometimes  intermixed  with  red  oils  for  the 
purpose  of  soapmaking  in  this  way ;  but,  as  a  rule,  they  are  not 
suitable  alone  for  the  preparation  of  soap  of  good  quality. 
Resinate  of  soda  (rosin  dissolved  in  soda  ley)  used  in  the  manu- 
facture of  rosin  soaps  (infra)  is  a  product  of  precisely  similar 
nature,  excepting  that  the  rosin  acids  do  not  belong  to  the 
ordinary  fatty  acid  families  described  in  Chap.  in. 

II.  Soapmaking  Processes  where   Glycerol  is   set  free 
taut  not  separated  from  the  resulting  Soap. — In  these  pro- 
cesses  natural  glycerides  are   employed,   being  acted  upon  by 
alkalies  (usually  caustic)  used  in  regulated  quantity   so  as  to 
suffice  to  saponify  the  total  fatty  matters  without  introducing 
any  large  excess  of  alkali ;  the  strength  of  the  ley  being  made 
such  that  the  product  becomes  more  or  less  solid  after  cooling 
and  standing,  the  glycerol  consequently  being  contained  in  the 
product. 

To  this  class  belong  more  particularly  soft  soaps  made  by 
boiling  together  appropriate  oils,  &c.,  and  potash ;  marine  soaps 
and  hydrated  soaps  prepared  in  similar  fashion,  mostly  with 
soda  and  largely  from  cokernut  or  palmnut  oil ;  socalled  cold 
process  soaps  of  various  kinds,  more  especially  certain  forms  of 
transparent  soaps,  perfumer's  soaps,  and  analogous  products ;  and 
certain  kinds  of  soap  prepared  under  pressure. 

III.  Soapmaking  Processes  where  the  Glycerol  set  free 
and  the  resulting  Soap  are  separated  from  one  another. 
— In  these  processes  the  essential  feature  is  that  glycerides  are 
more  or  less  completely  saponified  by  boiling  up  with  compara- 
tively weak  alkaline  leys,  and  the  soap  formed  "  salted  out ;'  by 
addition  of  brine  or  solid  salt  so  as  to  separate  it  as  a  pasty  mass 
from  the  watery  fluid  in  which  the  glycerol  remains  dissolved. 
The  half  made  soap  thus  obtained  is  then  finished  by  one  or 


DIRECT   NEUTRALISATION    PROCESSES.  451 

other  of  various  processes,  leading  to  the  production  of  some 
variety  of  "curd,"  "mottled,"  or  "fitted  soap;"  whilst  the 
watery  liquors  are  either  thrown  away  or  utilised  by  boiling 
down  so  as  to  recover  more  or  less  of  the  dissolved  salt  for  use 
over  again,  and  ultimately  obtain  the  glycerol  in  an  impure  form 
(vide  Chap,  xxn.)  As  regards  the  magnitude  of  the  scale  on  which 
they  are  made,  and  the  total  quantity  manufactured,  boiled  soaps 
of  this  class  are  the  most  important  of  all.  Additional  materials 
are  frequently  added  to  the  soap  thus  prepared  for  special  pur- 
poses —  e.g.,  silicate  of  soda,  borax,  and  aluminate  of  soda,  to 
increase  the  detergent  action  of  household  and  laundry  scouring 
soaps  ;  sulphate  and  carbonate  of  soda,  to  stiffen  and  harden  the 
soap,  and  prevent  it  from  wasting  too  rapidly  in  use  ;  resinate  of 
soda,  in  the  manufacture  of  yellow  soaps  ;  carbolic  acid,  creosote 
oils,  and  similar  substances,  in  the  manufacture  of  disinfecting 
soaps  ;  and  so  on.  When  potassium  carbonate  is  thus  added  to 
molten  soda  soap  in  not  too  large  a  quantity  double  decomposi- 
tion takes  place  between  the  sodium  salts  of  the  fatty  acids  and 
the  potassium  carbonate  ;  thus  in  the  case  of  stearate  — 

Sodium  Potassium  Potassium  Sodium 

Stearate.  Carbonate.  Stearate.  Carbonate. 


2Na.C18H3502      +      K2C03      -      2K.C18H3502     +     Na2CO3 

The  result  of  this  is  accordingly  the  formation  of  a  certain  pro- 
portion of  comparatively  soft  potash  soap  instead  of  the  harder 
soda  soap,  which  alters  the  texture  of  the  mass  ;  this  operation 
of  "  pearlashing  "  is  consequently  employed  in  the  preparation  of 
certain  kinds  of  toilet  soaps  (infra).  On  the  other  hand,  if  fatty 
matters  be  saponified  with  boiling  potash  ley,  and  the  resulting 
soap  salted  out  with  ordinary  salt,  the  opposite  kind  of  change 
takes  place,  soda  soap  and  potassium  chloride  being  formed  — 
e.g.,  in  the  case  of  palmitate  — 

Potassium  Sodium  Potassium  Sodium 

Pulmitate.  Chloride.  Chloride.  Palinitate. 

K.C16H3102       +       NaCl       -       KC1       +       Na.C16H3l02 

In  the  earlier  days  of  soapmaokingfwhen  woodash  was  the  most 
available  form  of  alkali,  this  reaction  was  of  some  technical 
importance  as  enabling  a  hard  soda  soap  to  be  obtained  in  lieu  of 
a  soft  greasy  product  ;  but  although  the  effect  appears  to  have 
been  known  and  the  operation  practised  to  some  considerable 
extent,  it  is  doubtful  if  the  chemical  nature  of  the  change  was 
understood  until  recently  (vide  Chap,  xxi.) 

DIRECT  NEUTRALISATION  PROCESSES. 

The  preparation  of  soap  by  the  direct  combination  of  free  fatty 
acids  and  alkalies  is  an  extremely  simple  operation,  more  especi- 
ally when  the  alkali  is  caustic  ;  all  that  is  required  is  a  suitable 
mixing  pan  provided  with  an  agitator  so  that  the  fluid  ingredients 


452 


OILS,    FATS,    WAXES,    ETC. 


can  be  intimately  intermixed.  Fig.  139  represents  a  steam 
jacketted  pan  with  steam  pipes,  ppp,  projecting  upwards  into 
the  pan,  whilst  an  agitator,  <?,  worked  by  bevel  wheels,  carries 
a  series  of  vertical  vanes  projecting  downwards,  so  that  clots  are 
broken  up  by  the  interlacing  of  the  pipes  and  vanes.  Another 
form  of  agitator  consists  of  two  sets  of  rods  or  vanes  made  to 
revolve  in  opposite  directions  by  means  of  bevel  wheels.  The 
red  oils,  &c.,  are  run  into  the  pan  (steam  jacketted  for  large 
operations)  and  heated  up  ;  the  alkaline  ley  is  gradually  run  in 


Fig.  139. 

with  agitation,  and  finally  the  hot  pasty  mass  transferred  to  a 
"frame"  in  which  it  solidifies  to  a  block  of  soap. 

A  slight  surplus  of  alkali  is  practically  imperative  in  order  to 
ensure  complete  conversion  of  the  fatty  acid  into  soap ;  this 
surplus  mostly  remains  disseminated  through  the  mass  as  it 
solidifies,  although  a  small  quantity  generally  exudes  as  a  watery 
fluid  ;  by  carefully  regulating  the  quantities  used  the  excess 
may  when  requisite  be  diminished  considerably  below  that  indi- 
cated in  the  example  given  below,  where  5  parts  of  free  alkali 
are  reckoned  for  40  combined,  representing  a  ratio  of  1  to  8 


RESINATE   OF    SODA.  453 

or  12-5  to  100.  On  the  other  hand,  for  soaps  intended  to  be 
highly  detergent  a  larger  excess  of  alkali  is  intentionally  used. 

Carbonated  alkali  is  sometimes  used,  instead  of  caustic,  in  the 
preparation  of  "  oleine  soap "  (Morfit's  process) ;  of  late  years, 
however,  the  facilities  for  obtaining  solid  caustic  soda  as  a  com- 
mercial product  have  increased  so  largely  that  the  slight  saving 
in  cost  effected  by  the  use  of  the  former  is  generally  considered 
to  be  more  than  outweighed  by  the  increased  amount  of  trouble 
involved  in  the  process.  When  employed,  the  mixing  pan  is 
fitted  with  a  large  movable  "  curb  "  (a  funnel  or  barrel  shaped 
top — Fig.  113)  in  which  the  froth  rises,  due  to  the  liberation  of 
carbonic  acid,  and  the  operation  is  carried  out  somewhat  more 
slowly  to  avoid  frothing  over. 

With  inferior  soaps,  largely  made  from  recovered  greases  and 
such  like  materials,  silicate  of  soda  is  sometimes  mixed  or 
"  crutched  "  into  the  mass  when  the  combination  is  complete, 
just  before  running  into  the  frames.  For  this  purpose  crutching 
machines,  such  as  those  represented  by  Figs.  127  to  130,  are  con- 
veniently used.  Resinate  of  soda  is  also  employed  as  an  ingredient 
to  increase  the  detergent  action.  On  the  other  hand,  with  soaps 
required  to  contain  as  little  free  alkali  as  possible,  not  only  is 
great  care  taken  to  reduce  the  proportion  of  free  alkali  present 
to  the  minimum  consistent  with  proper  combination  of  the  fatty 
acids,  but  in  special  cases — e.g.,  for  wool-scouring  soaps  and 
soaps  used  in  the  silk  industries,  further  means  are  adopted  to 
render  the  small  excess  innocuous.  One  method,  found  in 
practice  to  be  very  effective  (patented  by  the  author),  consists 
of  the  addition  of  a  regulated  quantity  of  an  ammoniacal  salt 
(usually  dissolved  in  a  minimum  of  water)  to  the  pasty  mass, 
and  well  incorporating  by  a  crutching  machine  or  otherwise 
before  running  into  the  frame.  Any  free  alkali  is  thus  neutralised 
by  the  acid  contained  in  the  ammoniacal  salt,  with  the  formation 
of  an  equivalent  amount  of  free  ammonia.  This  latter  mostly 
escapes  when  the  soap  is  cut  into  bars  and  stored,  but  the  little 
that  remains  is  beneficial  rather  than  injurious  to  wool  and  silk, 
unlike  the  original  free  fixed  alkali. 

Resinate  of  soda  is  often  prepared  for  intermixture  with  soaps 
of  various  kinds  by  boiling  up  rosin  with  rather  less  than  twice 
its  weight  of  soda  ley  of  about  16°  T.  (specific  gravity  1'08),  con- 
taining about  7  per  cent,  of  NaOH  *  until  completely  dissolved. 
The  liquid  sets  to  a  sort  of  thin  jelly  when  cold,  containing  the 
soda  salts  of  the  rosin  acids  and  more  or  less  excess  of  alkali, 
according  to  the  quantity  used.  Any  kind  of  pan  will  answer  if 
furnished  with  a  wet  steam  coil,  or  with  an  agitator  and  some 
other  suitable  means  of  heating.  Morfit's  steam  twirl  (Fig.  Ill, 
p.  429)  answers  well. 

*  The  saponiti cation  equivalent  of  rosin  usually  lies  between  330  and  370, 
so  that  10U  parts  of  rosin  correspond  with  between  10'8  and  12*1  parts  of 
NaOH. 


454  OILS,    FATS,    WAXES,    ETC. 

Calculation  of  Quantity  and  Strength  of  Ley  required, 
and  of  Composition  of  resulting  Soap. — The  quantity  of  ley 
of  a  given  strength  employed  depends  partly  on  the  mean  equi- 
valent of  the  oleine,  £c.,  used,  and  partly  on  the  amount  of  excess 
of  alkali  intended  to  be  added  to  ensure  complete  neutralisation 
and  communicate  extra  detergent  properties  to  the  soap  ;  whilst 
the  exact  strength  employed  depends  on  the  proportion  of  water 
the  finished  soap  is  intended  to  contain.  Assuming  the  oleine 
to  be  pure  oleic  acid,  its  saponificatioii  equivalent  would  be 
282 — i.e.,  282  parts  of  oleine  would  neutralise  40  of  NaOH  in 
accordance  with  the  reaction. 

Gleic  Acid.          Caustic  Soda.          Sodium  Oleite.  Water. 

C]SH34Oo     +     NaOH  NaC18H33O2     +     H20 

Supposing  the  ley  to  be  a  pure  solution  of  sodium  hydroxide,  if 
such  a  quantity  were  used  as  would  contain  45  parts  of  NaOH, 
5  would  consequently  remain  unneutralised,  or  the  "  free  alkali '' 
would  bear  to  the  "  combined  alkali "  the  ratio  5  to  40  =  1  to  8 
=  12*5  per  cent.;  if,  then,  140  parts  of  ley  were  used,  containing 
45  of  NaOH  (32-1  per  cent),  neglecting  mechanical  losses  and 
evaporation,  the  resulting  mass  would  consist  of  282  +  140  =  422 
parts,  made  up  thus — 

Sodium  oleate,  .         .     304  parts  72 '04  per  cent. 

Excess  of  caustic  soda,      .         5     ,,          =        1'18       ,, 
Water,     .         .         .         .     113    ,,         =     26'78      „ 


422  100-00 

The  113  parts  of  water  are  made  up  of  140  —  45  =  95  parts  con- 
tained in  the  ley  used,  arid  18  parts  formed  by  the  above 
reaction. 

If  a  proportionately  larger  amount  of  weaker  ley  were  used 
containing  45  parts  of  NaOH  in  160  (28-1  per  cent,  of  NaOH) 
the  resulting  mass  would  consist  of  282  +  160  =  442  parts, 
made  up  thus — 

Sodium  oleate,          .         .         .       304  parts  =  68 '78  per  cent. 
Excess  of  caustic  soda,     .         .  5      ,,  1'13         ,, 

Water, 133     „       =   30'09 

442  100-00 

On  the  other  hand,  if  a  proportionately  less  amount  of  stronger 
ley  were  used  containing  45  parts  of  NaOH  in  120  (37 '5  per 
cent,  of  NaOH)  the  composition  of  the  resulting  282  +  120 
=  402  parts  would  be — 

Sodium  oleate,         .         .         .       304  parts  =   75  "62  per  cent. 
Excess  of  alkali,       .         .         .  5      „      =      1'24 

Water, 93     „=  23'14        „ 

402  100-00 


CALCULATIONS.  455 

In  similar  fashion  the  strength  and  quantity  of  ley  requisite  for 
any  other  given  mixtures  of  free  fatty  acids  can  be  calculated  ; 
thus  suppose  the  mean  equivalent  of  the  fatty  acids  to  be  E,  and 
that  the  surplus  free  alkali  is  to  be  n  per  cent,  of  that  combined 
as  soap ;  then  for  E  parts  of  fatty  acid  a  quantity  of  ley  must  be 

used  containing  40  x  — ^—    =  CH  x  (100  +  n)  parts  of  NaOH 

altogether.      With  a   ley   containing   saline   matters    (chloride, 
sulphate,  &c.)    representing    m  parts    per    100    of   NaOH,    the 

quantity    of   saline    matter    will    be      -^-=    x  0*4   x  (100  +  n)  = 
0-004  x  m  x  (100  +  n);  so  that  a  weight,  W,  of  ley  will  contain — 

NaOH, 0'4      x  (100  +  n) 

Saline  matters,          ....       m  x  0'004  x  (100  +  n) 
Water,      .         .         .         .     W  -  O'OOl  x  (100  +  m)  (100  +  n) 

Hence  the  total  water  present  will  be — 

18  +  W  -  0-004  x  (100  +  m)  (100  +  »), 
and  the  resulting  soap  will  consist  of — 

Sodium  oleate,          E  +  40  -  18      .         .         .         .         * ;  ;     =  E  +  22 
Excess  of  NaOH,  — -  x  40 =0'4xn. 

Saline  matters,      -™_   x  0'4  x  (100  +  n) .         =  0'004  x  m  x  (100  +  n) 
LOO 

Water, W  +  18  -  0-004  (100  +  m)  (100  +  n) 


Total, E   +  W. 

Suppose  that  w  parts  of  resinate  of  soda  solution  be  added  to 
the  soap,  consisting  of — 

Resinate  of  soda,  .         .         ..-  .         .         a  parts. 

Excess  of  NaOH, b      ,, 

Water, w  -  (a  +  b)      „ 

then  the  total  mass,  neglecting  mechanical  loss  and  evaporation, 
will  consist  of — 

Soap  (sodium  oleate  +  resinate),    .         .         .  E  +  a  +  22 

Excess  of  NaOH, 0'4  x  n  +  b 

Saline  matters,       ....         0'004  x  m  x  (100  +  ») 
Water,     W  +  w  +  18  -  {0'004  (100  +  m)  (100  +  n)  +  a  +  b} 

Total, E   +  W  +  w. 

If,  on  the  other  hand,  w   parts  of  silicate  of  soda  be  added, 
containing — 

Silicate  of  soda  and  other  saline  matters,       .         .         c  parts. 

Excess  of  NaOH, d      ,, 

Water, w'  -  (c  +  d)    ,, 


456  OILS,    FATS,    WAXES,    ETC. 

then  the  total  mass  will  contain — 

Sodium  oleate,     .         .         .         .         .         .         .         .         .          E  +  22 

Excess  of  NaOH, 0'4  x  n  -f  d 

Sodium  silicate  and  other  saline  matters,    .     0'004  x  m  (100  +  n)  +  c 
Water,         .          W  +  w'  +  18  -  {0'OP4  (100  -  m)  (100  -  n)  +  c  +  d] 

Total,     . E  +   W  +  «;'. 

These  various  quantities  are  readily  calculated  into  per- 
centages when  the  values  of  E,  m,  n,  a,  b,  c,  c/,  W,  w,  w'  are 
given  for  any  particular  case — e.g.,  suppose  E  =  280,  n  =  10, 
m  =  12,  and  W  =  150  in  the  case  of  a  soap  not  treated  with 
resinate  or  silicate,  &c.,  then  the  composition  is — 

Sodium  oleate,       .         .  .         2SO  +    22  =  302  "0  =  70 '23  per  cent. 

Excess  of  NaUH,  .         .  .          0'4  x     10  =  4/0  =  0'93 

Saline  matters,      .         ,  0'004  x  12  x  110  =  5'2S  =       1-23        ,, 

Water,       .     150+  18  -  0'004  x  112  x  110  =  11872  =  27  61 


Total, 280  +  150  =  430  00  =   100 '00 

and  similarly  in  other  cases. 

SOAPMAKING  PROCESSES  WHERE  THE  GLYCEROL 
IS  SET  FREE  BUT  NOT  SEPARATED. 

The  methods  of  this  character  may  be  divided  into  three 
classes  according  to  the  temperature  and  pressure  employed.  In 
socalled  "cold  process"  soaps  the  materials  to  be  saponified  and 
the  alkaline  ley  are  intimately  intermixed  in  open  vessels  at 
temperatures  usually  considerably  below  the  boiling  point,  and 
allowed  to  stand  until  the  action  is  complete,  the  leys  used 
being  of  sufficient  strength  to  yield  a  product  not  too  moist. 
"  Hydrated  "  soaps  (including  "  marine  "  soap)  and  "  soft  "  soaps 
are  prepared  by  boiling  together  the  materials  under  the  ordinary 
pressure ;  whilst  soaps  prepared  under  increased  pressure  are 
treated  in  closed  vessels  so  as  to  obtain  a  still  higher  temperature 
for  the  purpose  of  shortening  the  operations  and  rendering  them 
more  complete.  In  all  cases  the  amount  of  alkali  employed  must 
be  carefully  proportioned  to  the  quantity  of  fatty  matters  used 
and  their  mean  saponification  equivalent,  otherwise  either  an 
imperfect  soap  will  result  containing  more  or  less  unaltered 
grease  owing  to  the  use  of  a  deficiency  of  alkali,  or  a  strongly 
alkaline  one  through  the  use  of  too  great  an  excess.  Sometimes 
these  two  faults  occur  simultaneously  through  the  action  not 
having  been  completely  carried  through  ;  this  is  not  unfrequently 
the  case  with  soaps  made  on  the  small  scale  with  highly  scented 
materials  (perfumer's  soap),  where  avoidance  of  much  rise  of 
temperature  is  indispensable,  since  otherwise  the  delicacy  of  the 
odour  would  be  deteriorated,  so  that  the  product  is  apt  to  contain 


COLD    PROCESS    SOAPS. 


457 


simultaneously  unaltered  fatty  glycerides  and  uncombined  caustic 
alkali.  Soaps  of  this  kind,  however,  have  now  been  largely  driven 
out  of  the  market  by  "  milled  "  toilet  soaps  where  the  evil  effect 
of  heat  on  delicate  perfumes  is  avoided,  and  at  the  same  time  a 
perfectly  made  soap  ensured,  by  mixing  a  good  kind  of  stock 
soap  with  the  scenting  materials,  &c.,  by  machinery,  grinding 
them  together  in  the  cold  (vide  infra,  also  p.  446). 

Cold  Process  Soaps. — For  the  preparation  of  cold  process 
soaps  on  the  large  scale  a  "  Hawes'  boiler  "  is  convenient.  The 
fatty  matters  (tallow,  either  alone  or  mixed  with  palm  oil  or 
lard,  and  preferably  a  small  quantity  of  cokernut  oil,  the  presence 
of  which  facilitates  the  saponification;  or  other  similar  mixtures) 
are  introduced  into  a  pan  such  as  that  indicated  in  Fig.  140,  or  into 
a  horizontal  cylinder,  Fig.  141  (5  to  6  feet  diameter),  provided 


D 


Fig.  140. 


Fig.  141. 


with  a  mechanical  agitator  and  heated  till  sufficiently  fluid,  usually 
to  about  45°  C.  (about  113°  F.)  Strong  soda  ley  of  about  specific 
gravity  1-33  (66°  Twaddell,  containing  about  24  per  cent,  of 
NaOH)  is  then  run  in  in  sufficient  quantity  (approximately  two 
parts  of  fat  to  one  of  ley,  the  exact-  proportion  varying  with  the 
mean  saponification  equivalent  of  the  fatty  matters),  with  con- 
tinuous agitation  until  the  whole  becomes  pasty  and  thoroughly 
intermixed ;  the  paste  is  then  run  out  into  a  wooden  frame  and 
well  covered  up  to  keep  in  the  heat ;  as  warmth  is  produced  by 
the  saponification  change,  the  mass  doe^sjjiofr  cool  until  the  action 
is  completed ;  at  first  the  change  takes  place  only  languidly,  but 
after  a  while  it  becomes  more  rapid  and  the  mass  sensibly  heats ; 
by  and  bye  as  the  action  approaches  completion  the  temperature 
begins  to  fall  again.  If  the  materials  are  too  highly  heated  at 
first  the  paste  is  apt  to  be  too  fluid,  so  that  unsaponified  grease 
and  watery  ley  tend  to  separate  partially  during  the  period  of 
standing,  thus  yielding  an  imperfect  product.  Instead  of  soda 
alone  a  mixture  of  soda  and  potash  (the  former  largely  predomi- 
nating) is  often  employed  with  the  object  of  obtaining  a  product 
of  superior  texture. 


458  OILS,    FATS,    WAXES,    ETC. 

Certain  kinds  of  transparent  soaps  (often  termed  "glycerine 
soaps")  are  frequently  prepared  by  means  of  a  modification  of 
the  cold  process ;  the  warm  fatty  materials  employed  (of  which 
castor  oil  is  generally  a  considerable  ingredient  on  account  of 
its  ready  saponifiability  and  its  tendency  to  form  translucent 
soaps)  are  intimately  intermixed  with  soda  ley  (and  in  certain 
cases  a  small  proportion  of  alcohol)  ;  soluble  colouring  matters 
<and  essential  oils  and  other  scents  are  then  stirred  in  and 
the  whole  allowed  to  stand  until  saponification  is  complete  : 
with  suitably  chosen  ingredients  and  proportions  the  resulting 
block  of  soap  is  more  or  less  transparent,  the  presence  of 
the  glycerol  formed  on  saponification  tending  to  cause  the 
soap  to  assume  a  "colloid"  or  gum-like  structure  instead  of 
the  semicrystalliiie  opaque  condition  usually  developed  in 
ordinary  hard  soaps.  When  alcohol  is  not  used  as  an  ingre- 
dient in  the  mass,  the  transparency  is  usually  only  imperfect, 
but  by  incorporating  extra  glycerol  instead  a  highly  transparent 
mass  can  be  readily  obtained.  Cane  sugar  effects  the  same  result, 
and  is  generally  employed  instead  of  either  alcohol  or  glycerol 
on  account  of  its  cheapness ;  but  the  effect  on  the  nature  of  the 
resulting  product  is  by  no  means  the  same,  inasmuch  as  saccharine 
substances  are  apt  to  produce  a  very  unpleasant  irritating  effect 
when  applied  to  highly  sensitive  skins  (ladies',  babies',  invalids', 
and  so  forth).  This,  moreover,  is  apt  to  be  greatly  aggravated 
by  the  presence  of  a  more  or  less  considerable  excess  of  alkali  in 
the  soap  mass,  necessarily  added  to  effect  complete  saponification,* 
inasmuch  as  muddiness  is  apt  to  be  produced  if  any  of  the  fatty 
glycerides  remain  unchanged,  which  is  likely  to  be  the  case, 
unless  some  excess  of  caustic  alkali  is  present.  It  accordingly 
results  that  many  kinds  of  transparent  socalled  "  glycerine  soaps  " 
are  of  the  worst  possible  quality  from  the  point  of  view  of  liability 
to  excoriate  and  irritate  extremely  tender  skins ;  although  their 
appearance,  when  attractively  tinted  and  agreeably  scented,  render 
them  apparently  very  elegant  articles. 

The  cheaper  kinds  of  transparent  soap  of  this  description  are 
often  extensively  "  filled  in  "  with  liquid  paraffin  and  petroleum 
hydrocarbons  which  possess  the  property  of  blending  with  the 
sugary  soap  mass  without  seriously  interfering  with  either  its 
consistency  or  transparency  ;  taking  into  account  some  20  to 
25  per  cent,  of  "loading"  thus  introduced,  together  with  some 
12  to  18  per  cent,  of  sugar,  and  20  to  25  per  cent,  at  least  of 
water,  it  often  results  that  the  actual  soap  present  does  not 
exceed  33  to  40  per  cent,  of  the  mass.  On  the  other  hand,  a 
well  made  soap  where  the  minimum  possible  excess  of  alkali 
only  has  been  used,  where  the  rate  of  saponification  and  ten- 
transparent  soaps  made  by  the  "spirit  process"  (infra)  are  generally 
free  f roui  this  defect,  although  as  usually  sent  into  the  market  they  contain 
considerable  amounts  of  cane  sugar.  . 


SOFT    SOAPS.  459 

dency  to  colloidal  structure  of  the  product  have  been  intensified 
by  the  use  of  an  admixture  of  spirit  in  the  original  materials, 
together  with  a  little  glycerol  instead  of  sugar,  and  where  no 
loading  has  been  added,  not  only  contains  a  far  larger  proportion 
of  useful  ingredients  of  much  better  quality,  but  also  for  that  very 
reason  resists  the  wasting  and  solvent  action  of  water  (especially 
when  hot)  much  more  completely,  and  is  consequently  much  more 
economical  in  use,  as  well  as  comparatively  free  from  corrosive* 
action,  on  delicate  skins. 

Soft  Soaps. — Potash  soaps  appear  to  possess,  on  the  whole,  a 
greater  tendency  to  assume  the  colloid  form  than  soda  soaps,  in 
consequence  of  which,  when  prepared  from  suitable  fatty  matters, 
they  are  more  inclined  to  be  jelly-like  and  transparent  or  trans- 
lucent, than  to  form  comparatively  hard  opaque  semicrystalline 
masses  like  ordinary  soda  soaps;  moreover,   they  are  generally 
deliquescent,   so  that  they  do  not  readily  dry  up.     The  precise 
texture  of  a  given  mass,  however,  largely  depends  on  the  tempera- 
ture, as  in  cold  weather  crystalline  grains  often  form,  more  especi- 
ally when  the  fatty  matters  used  contain  palmitic  or  stearic  acid : 
soap  exhibiting  this  peculiarity  (known  as  "  figging  ")  is  gener- 
ally supposed  to  be  of  superior  quality  for  that  reason,  although 
on  what  grounds  it  is  difficult  to  say  ;  the  granular  appearance 
is   sometimes  imitated  by  mixing  in  starch,  clay,  steatite,  &c. 
Linseed  and  other  drying  oils  (poppy  seed,  hempseed,  &c.)  ;  non- 
drying  and   semidrying  vegetable  oils   (such  as  rape,   camelina, 
and  cotton  seed)  and  similar  animal  oils  (train,  liver,  arid  fish 
oils);  together  with  the  "red  oils"  of  the  candlemaker  (crude 
oleic  acid),  are  those  most  largely  employed  in  the  manufacture 
of  soft  soaps,  a  little  tallow  being  added  to  furnish  stearate  for 
"figging,"  and  in  many  cases  indigo  in  small  quantity  so  as  to 
give  a  greenish  shade  (by  conjunction  with  the  yellow  tinge  of 
the  untinted  soap) ;  this  tint  being  natural  to  hemp  seed  oil,  and, 
therefore,  artificially  imitated  in  other  cases.    When  whale  and  fish 
oils  are  employed  an  unpleasant  smell  is  apt  to  be  communicated 
to  linen,  &c.,  washed  with  such  soap.     Considerable  practice  and 
skill  is  requisite  in  boiling  soft  soap,  although  the  actual  opera- 
tions are  of  the  simplest  character  ;  the  "  copper  "  or  pan  (usually 
made  of  iron  plates  rivetted  together  boiler- fashion — Fig.  112) 
in  which  the  boiling  takes  place  was  formerly  mounted  over  a 
free  fire,  but  is  now  generally  heated  by  means  of  two  steam 
coils,   one  for  "  dry  steam  "   (i.e.,  simply  a  coil  through   which 
superheated  steam  circulates  so  as  to  heat  up  the  contents  of 
the  pan),  the  other  for   "  wet  steam  "  (i.e.,  a  coil  perforated  with 
holes,  so  that  when  steam  is  let  in  from  the  boiler  it  escapes  into 
the  mass  through  the  holes,  heating  it  up  and  becoming  itself 
condensed,  until  the  temperature  is  so  high  that  the  steam  simply 
blows  through).     Figs.  1 14,  1  ]  5  illustrate  a  pan  fitted  with  the  two 
kinds  of  steam  coils.     The  mixed  fatty  matters  are  run  into  the 


460  OILS,    FATS,    WAXES,    ETC. 

copper  so  as  to  fill  it  to  about  one-fifth  or  one-fourth  of  its  capacity ; 
the  whole  is  then  heated  up  (by  free  fire  when  that  is  used,  by 
means  of  the  dry  steam  coil  if  no  free  fire  is  employed),  and  whilst 
heating  potash  ley  (usually  of  specific  gravity  1  -07  to  1  -08)  is 
slowly  run  in.  This  ley  is  found  by  experience  to  act  better  if 
not  completely  causticised,  a  portion  (some  15  to  25  per  cent.)  of 
the  alkali  being  still  carbonated  ;*  the  heat  should  be  so  applied, 
and  the  rate  of  supply  oc  ley  so  adjusted,  that  by  the  time  that  a 
volumn  of  liquor  about  equal  to  that  of  the  oil  has  been  run  in, 
the  whole  mass  is  beginning  to  boil  ;  to  prevent  frothing  over  a 
"fan"  (Fig.  116)  is  conveniently  arranged  over  the  pan.  The 
boiling  is  continued  with  wet  or  dry  steam,  usually  the  former, 
with  further  additions  of  ley  from  time  to  time,  until  the  proper 
consistency  and  appearance  are  arrived  at  as  judged  by  taking 
out  samples  and  quickly  chilling  them  ;  as  long  as  an  insufficient 
quantity  of  ley  has  been  used  a  visible  appearance  of  unsaponified 
fat  is  manifest,  giving  a  peculiar  border  to  the  sample  ;  whilst  if 
excess  has  been  added  the  sample  more  or  less  tends  to  separate 
into  two  different  portions,  one  of  soap,  the  other  of  watery  liquor; 
in  this  case  more  oil  (agitated  and  emulsified  with  a  little  weak 
liquor  to  enable  it  to  mix  better  with  the  boiling  mass)  is  added, 
and  so  on  until  the  sample  sets  to  a  clear  translucent  mass. 
Finally  the  wet  steam  is  shut  off  and  the  mass  boiled  either  by 
dry  steam  or  free  fire  until  sufficiently  concentrated  by  evapora- 
tion, when  the  finished  soap  is  barrelled  or  put  up  in  canisters 
or  drums  for  sale. 

Some  makers  prefer  to  use  stronger  leys  in  the  first  instance 
(specific  gravity  1-120  to  1-150  =  24°  to  30°  Tw.),  whereby  less 
boiling  down  is  requisite  in  the  final  stage.  In  some  cases  a 
mixture  of  potash  and  soda  leys  is  employed,  the  former,  how- 
ever, always  constituting  more  than  half  of  the  total  alkali  (60  to 
75  per  cent.)  Soft  soap  containing  soda  is  apt  to  become  muddy 
in  cold  weather,  and  hence  is  preferably  made  only  in  summer. 

The  exact  nature  of  the  mixture  of  fatty  matters  employed  is 
generally  regarded  as  a  valuable  trade  secret ;  the  relative 
proportions  of  the  constituents  are  often  varied  somewhat 
according  to  the  season  ;  in  winter  the  consistency  of  the  product 
is  usually  much  greater  than  in  summer,  so  that  in  the  former 
case,  such  a  mixture  is  employed  as  would  (for  the  same  atmo- 
spheric temperature)  give  a  softer  jelly,  and  vice  versa.  For 
household  soft  soaps,  silicate  of  soda  (or  potash)  is  sometimes 
mixed  in  with  the  finished  soap,  whilst  rosin  is  often  added  to 
the  fatty  mixture  employed  as  basis ;  when  the  soap  is  intended 
for  silk  and  wool  scouring,  however,  such  admixtures  are  highly 

*  When  the  soft  soap  is  required  to  be  as  nearly  neutral  as  possible,  car- 
bonated alkali  is  undesirable  as  tending  to  give  a  product  containing  a 
larger  amount  of  "free  alkali"  than  that  obtainable  by  the  judicious  use 
of  caustic  alkali  free  from  carbonate. 


MARINE    SOAP.  401 

injurious,  partly  because  of  the  presence  of  silicated  alkali  in  the 
soap,  which  has  a  very  bad  effect  on  the  fibre  ;  partly  because 
soaps  thus  treated  usually  contain  a  larger  proportion  of 
uncornbined  potash  or  soda,  or  both,  than  genuine  well  made  soft 
soap.  It  is  generally  supposed  that  because  ordinary  woolgrease 
(suint)  naturally  contains  much  potash  and  but  little  soda,  there- 
fore soda  has  a  more  injurious  action  on  wool  fibre  than  potash. 
Apart  from  the  somewhat  illogical  character  of  this  reasoning, 
however,  there  does  not  seem  to  be  any  experimental  evidence 
extant  to  show  that  this  is  really  the  case ;  on  the  contrary, 
experience  seems  rather  to  indicate  that,  provided  a  soap  is 
sensibly  neutral  (i.e.,  devoid  of  alkali  uncombined  with  fatty 
acids),  it  is  but  of  little  consequence  whether  it  be  a  potash  soap 
or  a  soda  soap  as  regards  injury  to  the  fibre  of  wool  during  use 
in  scouring ;  on  the  other  hand,  a  highly  alkaline  potash  soap, 
otherwise  pure,  exerts  more  deleterious  action  than  a  compara- 
tively neutral  soda  soap ;  although,  without  doubt  an  alkaline 
soda  soap,  especially  if  silicated,  is  extremely  objectionable. 
Probably  the  prejudice  respecting  the  superiority  of  potash  over 
soda  soaps  for  wool  scouring  is  largely  due  to  the  inferiority  of 
the  soda  (silicated)  soaps  now  manufactured  in  great  quantity  for 
household  scouring  purposes,  when  compared  with  potash  soft 
soaps  of  good  quality  as  regards  the  amount  and  nature  of  the 
alkaline  constituents  present  other  than  true  soaps — i.e.,  com- 
pounds with  fatty  acids  ;  for  a  well  made  soda  (oleine)  soap  devoid 
of  silicate  or  other  forms  of  "  free  alkali,"  such  as  the  dealkalised 
soap  described  on  p.  453,  appears  to  be  in  practice  quite  as  well 
suited  for  wool  scouring  purposes  as  the  best  potash  soft  soap 
obtainable. 

Hydrated  Soaps.  —  The  term  "  hydrated  soap  "  is  often 
applied  to  soap  manufactured  in  much  the  same  way  as  soft  soap, 
but  made  with  soda  as  alkali,  and  with  fatty  matters  of  such 
nature  as  to  furnish  a  comparatively  hard  opaque  product  rather 
than  a  soft  jellylike  mass.*  Cokernut  or  palm  kernel  oil  is 
generally  an  ingredient  in  the  mixture  of  fatty  matters  used,  its 
presence  facilitating  the  saponification  of  other  fats  less  readily 
attacked  by  alkalies ;  when  this  substance  constitutes  the  great 
majority  or  the  whole  of  the  mass,  the  product  is  known  as 
marine  soap,  as  the  solubility  in  brine  of  the  soda  salts  formed 
from  cokernut  oil  is  sufficient  to  enable  it  to  form  a  lather  with 
seawater. 

Marine  Soap. — This  is  readily  prepared  by  boiling  up  together 
with  wet  steam  cokernut  or  palm  kernel  oil,  and  strong  soda  ley 
of  specific  gravity  about  1-15  to  M75  (30°  to  50°  Tw.),  the  latter 

*  In  Germany,  soap  of  similar  character  is  often  designated  eschweyer 
seife;  in  America,  the  term  "Swiss  soap"  is  similarly  applied.  Soaps  of 
this  kind  are  often  intermixed  with  boiled  soaps  containing  no  glycerol,  so 
as  to  form  products  of  mixed  character. 


4G2  OILS,    FATS,    WAXES,     ETC. 

being  run  in  slowly.  Saponification  proceeds  very  rapidly  when 
once  commenced,  the  mass  frothing  up  largely,  and  requiring  a 
largo  pan  and  curb  to  avoid  loss  by  boiling  over.  A  boiling 
temperature,  in  fact,  is  not  absolutely  necessary,  nor  even 
desirable  to  begin  with,  as  the  heat  liberated  by  the  action  rapidly 
raises  the  temperature,  whence  the  copious  frothing.  Owing  to 
the  low  saponification  equivalent  of  cokernut  oil  (about  210  to 
215),  a  much  larger  quantity  of  alkali  is  requisite  to  bring  about 
complete  saponification  than  is  the  case  with  most  other  kinds  of 
fatty  matter ;  100  parts  of  cokernut  oil  correspond  with  about 
19  of  NaOH,  whereas  100  parts  of  tallow  represent  only  about 
14  parts  of  NaOH  (vide  infra).  A  considerable  quantity  of 
silicate  of  soda  is  generally  run  into  the  finished  mass  and  well 
"  crutched  in"  (i.e.,  intermixed  by  agitation);  the  effect  of  this  is 
greatly  to  intensify  the  natural  tendency  of  cokernut  oil  soap  to 
form  a  tolerably  solid  mass,  even  when  incorporated  with  a  con- 
siderable amount  of  water ;  so  that  silicated  marine  soap  often 
contains  less  than  20  per  cent,  of  actual  soap  (sodium  salts  of 
fatty  acids),  and  upwards  of  70  per  cent,  of  water.  Such  a  soap, 
when  heated  alone,  generally  separates  into  two  distinct  sub- 
stances, viz.,  a  watery  solution  of  silicate,  etc.,  and  a  pasty  mass 
of  actual  soap.  On  account  of  this  tendency  to  separation,  the 
crutching  of  the  original  mass  must  be  prolonged  until  solidifica- 
tion is  tolerably  far  advanced,  in  order  to  ensure  a  uniform  pro- 
duct. Asa  general  rule,  the  price  at  which  such  highly  watered 
soap  is  sold  is  not  reduced  to  anything  like  the  extent  that  would 
correspond  with  the  amount  of  water  added. 

Hydrated  soaps  made  from  mixtures  containing  palm  oil, 
tallow,  bone  fat,  horse  grease,  &c.,  are  sometimes  silicated,  but 
are  more  frequently  hardened  by  crutching  in  a  strong  solution 
of  sodium  carbonate  (sometimes  together  with  sodium  sulphate), 
whereby  not  only  extra  detergent  quality  is  communicated,  but 
also  a  greater  degree  of  firmness,  enabling  a  larger  proportion  of 
water  to  be  present  without  rendering  the  soap  too  soft  for 
sale;  the  term  "hydrated"  (or  "watered"),  indeed,  is  originally 
derived  from  the  circumstance  that  the  method  of  manufacture 
enables  a  product  to  be  obtained  containing  a  much  larger  pro- 
portion of  water,  and  a  correspondingly  less  quantity  of  actual 
soap,  than  was  formerly  practicable  with  "  boiled  soaps  "  of  the 
third  class.  Even  with  these,  however,  it  has  been  found 
possible  to  produce  an  analogous  result  by  somewhat  similar 
devices,  more  especially  by  cautiously  crutching  in  saline  solutions 
(sodium  silicate,  carbonate,  &c.)  whilst  cooling  and  solidifying 
(vide  infra}. 

Hydrated  Soaps  prepared  under  Pressure.  —  A  large 
number  of  patents  have  been  taken  out  from  time  to  time  for 
various  processes  and  modifications  of  plant,  intended  to  shorten 
and  simplify  the  manufacture  of  hydrated  soaps  by  causing  the 


HYDRATED    SOAPS    PREPARED    UNDER    PRESSURE. 


463 


reaction  to  occur  at  a  more  elevated  temperature  under  increased 
pressure.  Thus  Tilghmann  proposed  the  use  for  soapmaking  of 
the  same  plant  as  used  by  him  for  hydrolysing  glycerides  by 
water  alone  (p.  385).  The  apparatus  that  has  been  generally 
found  to  answer  best  is  some  kind  of  autoclave  where  the 
mutually  adjusted  quantities  of  fatty  matter  and  lye  are  either 
run  in  through  a  manhole  or  pumped  in  through  a  pipe,  and 
then  heated  up  either  by  means  of  a  free  fire  or  by  blowing  in 
high-pressure  steam,  much  as  in  the  manufacture  of  "  steariiie }> 
for  candlemaking  (p. 
373).  Fig.  142  illus- 
trates Dunn's  plant, 
consisting  of  a  ver- 
tical boiler,  B,  with 
manhole  and  safety 
valve ;  the  fat  and 
ley  are  pumped  in 
through  the  safety 
pipe,  A,  and  the 
finished  mass  ejected 
through  the  empty- 
ing tube  and  cock,  C. 
Heat  is  communi- 
cated by  means  of 
free  firing,  the  tem- 
perature attained  be- 
ing determined  by 
means  of  a  long- 
stemmed  thermo- 


Fig.  142. 


meter,  inserted  in  a  tube  filled  with  mercury  or  paraffin  wax,. 
projecting  inwards  into  the  boiler.* 

In  Bennett  and  Gibb's  process  a.  horizontal  boiler  furnished 
with  an  agitator  is  employed,  somewhat  similar  to  that  used  by 
Hawe's  (p.  457) ;  into  this  are  continuously  pumped  at  one  end 
the  fatty  matters  to  be  saponified  and  soda  leys  not  causticised 
(sodium  carbonate  solution),  containing  the  appropriate  quantity 
of  alkali  (30  to  33  parts  of  soda  ash  at  48  per  cent.  Na2O 
dissolved  in  100  of  water  to  100  of  fatty  matter).  At  the  other 
end  the  finished  soap  mass  emerges  through  a  weighted  exit 
valve,  the  pressure  'being  maintained  at  220  to  280  Ibs.  per 
square  inch  (about  15  to  20  atmospheres,  corresponding  with  a 

*  This  boiler  also  serves  for  the  preparation  of  silicate  of  soda  (or  potash) 
solution.  The  boiler  is  charged  with  broken  up  flints  or  quartz  pebbles  and 
soda  ley  of  specific  gravity  1*15  to  1*175  (30°  to  35°  Tw.),  and  is  gradually 
heated  up  until  a  pressure  of  4  to  5  atmospheres  is  attained  (corresponding- 
with  a  temperature  of  about  150°  C.),  which  is  maintained  for  some  hours. 
At  the  end  of  this  time  the  soda  has  dissolved  silica  to  approximate  satura- 
tion ;  the  liquor  is  then  blown  off  into  a  settling  tank,  and  the  clear  portion 
used  for  intermixture  with  soap. 


464  OILS,    FATS,    WAXES,    ETC. 

temperature  of  190°  to  215°  C.)  At  this  higher  temperature  the 
carbonated  alkali  is  stated  by  the  inventor  to  act  as  efficiently  as 
caustic  alkali  at  lower  pressures. 

Calculation  of  Quantity  and  Strength  of  Ley  required 
and  of  Composition  of  resulting  Soap. — Much  the  same 
general  principles  apply  in  the  case  of  the  soaps  at  present 
under  discussion  as  in  the  case  of  those  prepared  by  direct 
neutralisation  of  fatty  acids  (p.  454),  the  chief  difference  being 
that  in  the  present  instance  no  water  is  formed,  whilst  the 
glycerol  produced  instead  must  be  taken  into  account.  If  E 
be  the  sapoiiification  equivalent  of  a  mixture  of  triglycerides, 
E  parts  by  weight  of  the  mixture  will  require  40  parts  of  NaOH, 
or  57 '1  parts  of  KOII,  for  sapoiiification,  and  will  produce  by 

92 

acting    thereon    '  '    parts    of  glycerol,   in    accordance   with    the 
o 

equation. 

Trk'lyceride.  Caustic  Soda.  G'ycerol.  Soda  Soup. 

CH2  .  OX  CH2  .  OH 

i  I 

CH    .OX     +    SNa.OH    =       CH    .  OH     +     3Na  .  OX 

CH2  .  OX  CH2  .  OH 

Suppose  that  a  soda  ley  is  used,  containing  m  parts  of  neutral 
saline  matters  (chloride,  sulphate,  £c.)  per  100  of  NaOH  ; 
and  that  the  proportion  of  ley  employed  is  such  that  for  100 
parts  of  NaOH  converted  into  soap  n  parts  are  employed  in 
excess.  The  total  NaOH  employed  will,  consequently,  be 

40  x  1"  n  =  0-4  (100  +  n)  parts  for  E  parts  of  fatty  matter 

as  before;  whilst  a  given  weight  of  ley,  W,  will  contain,  as 
before — 

NaOH, 0-4  x  (100 +  »») 

Saline  matters,        .         .         .     -™^  x  0'4  x  (100  +  n)  =  m  x  0'004  x  (100  +  w) 

Water,    W  -  0'4  (100  +  n)  -  0'004  x  m  (100  +  n)  =  W  -  0'004  (100  -H  m)  (100  +  n) 

Total, W 

Hence  the  resulting  soap  mass  (neglecting  mechanical  losses 
and|evaporation)  will  contain — 

Soda  soap,  E  +  40  -  -* -       .         .         .         .  E  +  9'33 

Glycerol,  ~  .....  -  30'67 

o 

Excess  of  NaOH,   T"7r  x  40          .         .         .         .  =  0'4  x  n 

100 

Saline  matters, 0'004  x  m  (100  +  n) 

Water, W  -  0'004  (100  +  m)  (100  +  n) 

Total,  E  +  W 


CALCULATIONS.  465 

In  the  case  of  a  potash  soap,  if  m  parts  of  neutral  saline 
matters  be  present  per  100  of  KOH,  and  if  n  parts  of  KOH  in 
excess  be  used  per  100  converted  into  soap,  the  total  KOH  used 

will  be  57-1  x  —  1Q*  n  =  0-571  x  (100  +  n)  per  E  parts  of  tri- 
glyceride  mixture;  whilst  a  given  weight  of  ley,  W,  will  contain — 

KOH, 0-571     x  (100  +  n) 

Saline  matters,  -^  x  0'571  x  (100  +  n)   =          0'0057l     x  m  x  (ICO  +  n) 
Water,     j  ^  '  0-57,1(100^)  -  0«B71 1  =  w  _  ^  (10D  +  m)  (100  +  n) 

Total, W 

Whence  the  entire  soap  mass  produced  will  consist  of — 

no 

Potash  soap,      E  +  57'1  -  ....  E  x  26'43 

o 

99 
Glycerol,  -^- =  30  "67 

Excess  of  KOH,   ^    x  57 '1  ....  =       000571  x  n 

Saline  matters, 0 '00571  x  m  x  (100  +  n) 

Water, W-0'00571  (100  +  m)  (100  +  n) 

Total, E   +  W 

Suppose  that  an  admixture  of  silicate  of  soda,  resinate  of  soda, 
syrup,  or  loading  of  any  kind  be  made  to  the  extent  of  w  parts 
by  weight,  the  composition  of  the  total  mass  will  be  similarly 
arrived  at ;  thus  suppose  a  mixture  of  fatty  matters  of  mean 
saponification  equivalent  290  (E  =  290)  be  saponified  with  excess 
of  soda  ley  such  that  W  =  160,  n  =  15,  and  m  =  10,  and  that  150 
parts  of  syrup  be  added  per  290  of  fatty  matters,  consisting  of — 

Sugar,        .         .       50  parts. 
Water,       .         .100       ,, 

150 

i.e.,  let  w  =  150  ;  then  the  composition  of  the  resulting  mass  will 
be — 

Soap,       .         .         .         .290  +  9-33  =  299 '33  =     49 -89  percent. 

Glycerol,          ...  -     30'67  -       5'11        „ 

Excess  of  NaOH,   .                0'4  x     15              =  6'00  =  I'OO       „ 

Saline  matters,        .           0'004  x     10  x  115  =  4'60  =  0'77 

Sugar, 50-00  =  8 '33 

Water,     .       160  +  100  -  0'004  x  110  x  115  =  209'40  =  34-90       „ 

Total,  290  +  160  +  150  =  (300 '00  =   100 '00 

30 


466  OILS,    FATS,    WAXES,    ETC. 

In  the  preparation  of  soft  soap,  the  quantity  of  ley  and  fatty 
matter  used  are  usually  not  adjusted  to  one  another  beforehand 
in  the  way  requisite  for  cold  process  soaps  \  the  ley  is  run  in 
gradually  during  the  operation  until  the  requisite  consistency  is 
attained,  more  fatty  matter  being  added  in  case  of  an  excess  of 
alkali  having  been  used,  practical  experience  in  carrying  out  the 
manipulations  being  the  guide  to  the  quantities  employed  rather 
than  accurate  weighing  or  measuring.  Similar  remarks  apply  to 
most  hydrated  soaps  prepared  by  boiling  in  open  pans ;  on  the 
other  hand,  for  soaps  made  under  pressure  in  autoclaves,  tfec., 
the  relative  quantities  of  materials  must  be  carefully  adjusted  at 
the  commencement  of  the  operation,  as  the  nature  of  the  process 
does  not  conveniently  admit  of  more  material  being  added  after 
the  operation  has  been  once  commenced  and  the  increased  pressure 
attained. 


SOAPMAKING  PROCESSES  WHERE  THE  GLYCEROL 

AND  SOAP  FORMED  ARE  SEPARATED 

FROM  ONE  ANOTHER. 

Methods  of  this  class  substantially  depend  upon  the  general 
principle  that  whereas  most  alkali  soaps  are  pretty  freely  soluble 
in  pure  water,  especially  when  hot,  the  presence  of  various  kinds 
of  neutral  saline  matter — e.y.,  common  salt — and  even  of  a  large 
excess  of  caustic  or  carbonated  alkali,  renders  them  insoluble ; 
so  that  the  addition  of  salt  or  strong  ley  to  an  aqueous  soap 
solution  causes  the  soap  to  separate  or  precipitate  in  more  or  less 
solid  flakes,  the  physical  structure  of  which  is  more  akin  to  that 
of  crystalloid  substances  than  to  the  colloid  gum-like  form  in 
which  transparent  soap  is  obtained.  The  process  of  manufacture 
may  accordingly  be  broadly  described  as  consisting  o^f  boiling  up 
the  fatty  matter  to  be  saponified  with  comparatively  weak  alkaline 
fluids  not  used  in  excess,  but  employed  in  such  quantity  that 
when  the  alkali  has  been  practically  all  neutralised  by  combina- 
tion with  the  fatty  acids  the  great  majority  of  the  fatty  matter 
is  decomposed,  the  remaining  portion  being  distributed  through 
the  soap  solution  formed  as  a  sort  of  emulsion.  At  this  stage, 
on  adding  solid  salt  or  strong  brine,  the  dissolved  soap  is  thrown 
out  of  solution  and  separates  as  a  more  or  less  granular  curd, 
carrying  with  it  the  unaltered  fat ;  the  watery  fluid  containing 
the  liberated  glycerol  being  run  off,  the  pasty  imperfect  soap  is 
further  treated  with  successive  small  quantities  of  stronger  ley, 
being  boiled  up  therewith  until  the  saponification  is  complete. 
Finally,  the  soap  is  "finished"  by  one  or  other  of  various  kinds  of 
operation,  according  to  the  nature  of  the  intended  product.  For 
"mottled"  soaps,  the  curd  resulting  after  complete  saponification 
is  boiled  down  (by  dry  steam,  or  in  the  older  w^ay  of  working,  by 


CURD    SOAP.  467 

free  fire),  together  with  excess  of  strong  ley,  until  it  acquires  a 
sufficient  consistency — i.e.,  until  it  is  so  thick  that  on  running 
into  the  frames  the  coloured  impurities  present  (iron  soap,  &c., 
formed  during  the  process,  or  produced  by  adding  green  vitriol, 
&c.,  to  the  curd)  are  unable  to  sink  to  the  bottom  by  gravitation; 
in  which  case,  as  the  mass  cools  and  solidifies,  these  coloured 
matters  segregate  into  veins  producing  "  mottling "  of  the  old 
fashioned  type.* 

For  "fitted"  soaps,  the  curd  produced  after  complete  saponifi- 
cation  is  effected  is  allowed  to  stand  awhile  so  as  to  separate 
from  the  leys ;  these  are  run  off,  and  the  curd  boiled  up  with 
wet  steam  and  weak  leys  or  water  until  it  is  sufficiently  thinned 
in  texture  to  permit  of  the  coloured  heavier  metallic  soaps  falling 
to  the  bottom  by  gravitation  on  standing  ;  with  rosin  soaps  more 
particularly,  peculiar  textures  ("coarse  fit,"  "fine  fit")  are  thus 
arrived  at,  respectively  suitable  for  different  purposes. 

Curd  Soap. — For  "cleansed"  curd  soaps,  the  diluted  curd 
thus  freed  from  coloured  impurities  is  pumped  off  into  another 
copper,  and  theie  boiled  up  with  dry  steam  and  a  small  quantity 
of  strong  ley  until  again  concentrated  to  the  required  extent 
(i.e.,  until  the  curd,  freed  from  ley  by  subsidence,  has  the  desired 
proportion  of  water  associated  with  it)  ;  the  water  retained  by 
the  curd  being  less  the  longer  the  boiling  is  continued,  and  the 
stronger  the  ley  (pp.  470,  4b6). 

In  boiling  for  curd  soap,f  the  first  saponification  operation  is 
usually  carried  out  by  running  into  the  copper  caustic  leys  of 
strength  not  exceeding  specific  gravity  1'05  to  1'075  (10°  to 
15°T.),J  together  with'  the  melted  fatty  matters,  and  boiling 
them  up  together.  The  way  in  which  this  is  done  varies  much 
in  different  cases  and  in  different  districts  ;  sometimes  *tKe  wfrole 
batch  of  "  goods  "  (fatty  matters)  is.  run  in,  and  then,  a  fraction 
of  the  ley,  and  the  whole  boiled  up^more  ley  bfeing  added  from 

*  Totally  distinct  from  the  modern"  mottled  soaps  of  highly  watered  and 
silicated  character — vide  p.  472. 

t  British  curd  soaps  are  almost  invariably  made  from  tallow  as  chief 
basis,  the  hard  difficultly  lathering  character  of  pure  tallow  soap  being 
modified  by  the  addition  of  other  oils  and  fats  (small  quantities  of  cokernut 
oil,  more  or  less  cotton  seed  or  groundnut  oil,  lard,  and  so  on),  according 
to  the  object  in  view.  On  the  Continent,  and  especially  in  France,  vegeta- 
ble oils  are  used  in  much  larger  proportion ;  thus  Marseilles  (Castile)  soap 
is  supposed  to  be  made  almost  wholly  from  olive  oil,  and,  in  point  of  fact, 
is  chiefly  prepared  from  the  highly  sophisticated  mixtures  sold  under  that 
name  ;  and  even  in  those  cases  where  tallow  is  used,  a  pretty  large  propor- 
tion of  mixed  vegetable  oil  is  generally  also  added,  rape  oil  being  generally 
one  of  the  constituents  added  to  give  lathering  qualities. 

%  Leys  containing  more  than  some  5  per  cent,  of  JSa20  act  much  less 
slowly  on  tallow  and  most  other  oils  and  fats  than  weaker  solutions,  at 
any  rate  in  the  first  instance.  When,  however,  the  action  is  once  fairly 
started,  somewhat  stronger  leys  may  be  run  in  (in  small  quantities  at  a 
time). 


468  OILS,    FATS,    WAXES,    ETC. 

time  to  time.  Sometimes  the  majority  of  the  ley  is  run  in  first, 
and  the  goods  added  in  successive  portions,  with  continuous 
boiling.  More  frequently  the  ley  and  goods  are  run  in  alter- 
nately until  the  full  complement  of  the  latter  is  in  the  kettle, 
with  somewhat  less  than  the  corresponding  quantity  of  ley,  the 
rest  of  which  is  subsequently  added.  When  wet  steam  is  used 
to  heat  up  the  copper  the  leys  initially  employed  may  be  a  little 
stronger  than  if  dry  steam  be  used  on  account  of  the  dilution 
with  condensed  water ;  the  later  leys  may  also  be  stronger  than 
the  first  ones,  as  they  become  greatly  diluted  with  the  water 
already  present  from  the  former  leys.  The  effect  of  the  action  of 
the  hot  ley  on  the  melted  fatty  matter  is  to  "kill  the  goods  " — 
i.e.,  to  emulsify  the  whole,  so  that  no  distinct  layer  of  melted  fat 
swims  up  on  taking  a  sample. 

When  the  saponification  has  gone  on  to  such  an  extent  that  a 
large  fraction  of  the  glycerides  is  acted  upon  and  but  little  alkali 
remains  dissolved  in  the  ley,  the  whole  mass  forms  a  homo- 
geneous pasty  mass,  consisting  of  the  half  made  soap  with 
portions  of  emulsified  fatty  matter  not  yet  saponified  distributed 
throughout  it.*  In  this  state  it  is  known  as  "close"  soap  (in 
some  districts,  as  being  in  a  "hitch"  or  "glue").  If  too  much 
ley  has  been  added  this  peculiar  texture  is  not  attained,  a  sample 
taken  out  on  a  trowel  exhibiting  more  or  less  marked  tendency 
to  separate  into  two  fluids,  one  more  watery  than  the  other  ; 
whilst,  if  the  boiling  has  not  been  continued  long  enough,  or  if 
the  ley  be  too  concentrated,  a  large  surplus  of  undecomposed  fat 
is  visible,  giving  a  greasy  texture  to  the  imperfectly  made  soap 
that  thus  separates  from  the  watery  ley.  With  proper  care, 

*  It  is  extremely  probable  that  the  saponifying  action  of  the  alkali  is 
exerted  in  three  stages,  forming  successively  one,  two,  and  three  molecules 
of  soda  soap  ;  thus  (in  the  case  of  stearin) — • 

Tristearin.  Caustic  Soda.  Distearin.  Sodium  Stearate. 

(O.C18H3;0  (O.C18H8fiO 

C3H5     O.C18H350  +  NaOH   =  C3H5  \  0.  C18H330  +   Na.  0.  C18H350. 
(O.C13H350  (OH 

Distearin.  Monostearin. 

I  O.C18H350  <O.CJ8H350 

C8H5{O.C18H350  +  NaOH   -  C3H5  \  OR  +  Na.  0.  C18H350. 

/OH  (OH 

Monostearin.  Glycerol. 

(O.C18H350  (OH 

C3H5  I  OH  +  NaOH   -  C3H5  \  OH  +  Na.  0.  C18H,50. 

(OH  (OH 

On  this  view  "half  made  soap;'  consists  of  a  mixture  of  sodium  stearate 
with  emulsified  tristearin,  distearin,  and  monostearin,  uniformly  dissemi- 
nated through  the  water  as  a  sort  of  jelly.  A  circumstance  favouring 
this  view  is  that  the  quantity  of  glycerol  obtainable  from  the  first  spent  leys 
is  considerably  less  than  the  amount  corresponding  with  the  goods  killed, 
not  much  above  one  half  as  a  rule. 


GRAINING.  469 

guided  by  indications  only  obtainable  by  practical  experience, 
the  requisite  physical  condition  is  attained,  representing  a  state 
of  matters  where  most  but  not  quite  all  of  the  fatty  matter  is 
saponified,  whilst  practically  all  the  caustic  soda  in  the  leys  has 
been  used  up,  furnishing  an  aqueous  soap  solution,  or  thin  jelly, 
with  a  little  emulsified  fat  disseminated  throughout. 

Graining. — The  next  stage  consists  in  "graining"  or  "cutting" 
the  soap  by  the  addition  of  sufficient  saline  matter  to  render  the 
dissolved  soap  insoluble  in  the  resulting  weak  brine.  For  this 
purpose  common  salt  is  used,  either  solid  fresh  salt  or  that 
regained  from  previous  batches  of  liquor  during  boiling  down  to 
recover  glycerol  (p.  514);  or  a  strong  brine  is  run  in.  The 
quantity  added  depends  on  the  proportion  of  water  already 
present  in  the  copper  relatively  to  the  soap,  which  in  turn 
depends  on  the  strength  of  the  leys  used  and  the  quantity  of 
water  condensed  from  "  wet "  steam  ;  moreover,  soaps  containing 
much  coker  or  palmnut  oil  require  more  salt  than  others,  cceteris 
paribus.  When  sufficient  salt  is  present  in  the  watery  liquor, 
a  sample  of  the  contents  of  the  copper  taken  out  on  a  trowel 
shows  a  mass  of  grains  of  semisolid  soap,  whilst  a  clear  watery 
fluid  runs  away,  which  should  not  be  markedly  alkaline  to  the 
taste,  and  should  throw  up  no  scum  of  fatty  acids  on  acidulation ; 
showing  that  practically  all  the  soda  used  has  been  converted 
into  soap,  and  all  the  soap  formed  thrown  out  of  solution  by  the 
addition  of  sufficient  salt.  Explosive  evolution  of  steam  (violent 
"  bumping ;;)  is  very  apt  to  occur  during  the  graining  process, 
whence  the  use  of  a  fan  and  curb  (p.  433)  in  moderating  the 
frothing,  whilst  the  kettle  or  copper  used  is  only  partly  filled 
with  materials. 

After  standing  for  a  few  hours  (steam  being  shut  off)  the 
contents  of  the  copper  separate  into  watery  "  spent  ley  "  which 
is  run  off  and  utilised  (for  glycerol  extraction,  &c.),  and  pasty 
"  grain  soap "  consisting  of  about  3  parts  actual  soap  to  2  of 
adherent  water  :  this  is  either  finished  at  once  (usually 
pumped  off  into  a  smaller  copper,  or  mixed  with  another  batch 
from  another  copper,  there  being  less  liability  of  violent  frothing 
over  during  the  subsequent  stages) ;  or  else  more  goods  are 
added  with  weak  ley  and  the  boiling  recommenced  as  before 
until  the  new  batch  of  fatty  matters  is  properly  "  killed,"  when 
the  whole  mass  is  again  salted  out. 

The  grained  soap,  freed  from  spent  ley,  is  then  boiled  up  with 
wet  steam  and  an  additional  quantity  of  somewhat  stronger  ley 
containing  some  9  per  cent,  of  NaOH  (specific  gravity  about 
1*09  to  I'll)  gradually  run  in  so  as  to  complete  the  saponification ; 
the  quantity  finally  added  being  sufficient  to  cause  the  mass  to 
separate  into  two  (aqueous  ley,  and  soap  paste),  the  excess  of 
caustic  soda  throwing  the  soap  out  of  solution  just  as  salt  does. 
In  some  cases  this  operation  is  carried  out  in  two  stages,  the 


470  OILS,    FATS,    WAXES,    ETC. 

alkaline  "  half  spent  "  ley  run  off  in  the  first  stage  being  utilised 
for  killing  fresh  goods  ;  this  ley  washes  out  entangled  brine  and 
contains  most  of  the  remaining  glycerol  developed  by  the  com- 
pletion of  the  saponification.  ]  11  the  second  stage  sufficient  water 
is  added  (including  that  condensed  from  wet  steam)  to  cause 
the  paste  to  again  assume  the  "  close  "  state  by  dilution  of  the 
leys  admixed  with  it,  and  the  boiling  continued  long  enough  to 
ensure  the  saponification  of  the  last  portions  of  glycerides,  when 
the  soap  is  again  grained  or  "made"  by  running  in  sufficient 
stronger  ley  to  throw  it  out  of  solution  in  grains.  Finally  the 
half  spent  leys  are  partly,  but  not  wholly,  run  off,  and  the  soap 
paste  and  remaining  ley  boiled  up  by  means  of  the  dry  steam 
coils,  so  that  water  is  evaporated,  whereby  the  residual  ley 
becomes  more  concentrated,  and  the  soap  paste  less  watery 
(p.  467)  :  when  the  paste  sets  on  cooling  to  the  required  con- 
sistency and  degree  of  hardness,  the  boiling  is  stopped  and  the 
mass  allowed  to  stand  some  hours  so  that  the  leys  and  curd  may 
thoroughly  separate  from  one  another  :  the. curd  is  then  trans- 
ferred to  the  cooling  frames.  Unless  purposely  watered  or 
boiled  down  to  a  less  extent,  curd  soaps  generally  contain  only 
20  to  25  per  cent,  of  water.  When  required  to  be  as  white  as 
possible,  the  curd  is  allowed  to  stand  for  some  time  before  the 
final  boiling  operation,  so  that  coloured  impurities  may  subside  ; 
the  "  cleansed  ;'  curd  is  then  ladled  or  pumped  off  into  another 
copper  in  which  the  boiling  down  with  close  steam  is  effected. 

The  time  occupied  during  these  various  operations  varies  with 
the  scale  of  operations  and  the  skill  of  the  workman  :  with  batches 
of  40  to  50  tons  of  goods  (tallow  and  rosin  for  yellow  soap)  the 
"  killing  "  may  be  effected  by  an  experienced  hand  in  one  day, 
and  the  further  process  up  to  "  making  "  the  soap  carried  out  on 
the  next  day,  the  whole  being  furnished  on  the  third  day  (Lant 
Carpenter). 

British  curd  soaps  are  usually  made  with  tallow  as  chief  in- 
gredient with  comparatively  small  admixtures  of  other  oils  and 
fats  ;  they  do  not  lather  very  freely,  and  "  waste  "  in  hot  water 
less  rapidly  than  many  other  kinds  of  soap.  The  term  "  curd  " 
soap,  however,  does  not  necessarily  denote  a  tallow  soap,  but 
rather  a  soap  boiled  in  a  particular  way. 

Fitted  Soaps. — In  the  manufacture  of  curd  soaps  more  or  less 
of  the  alkaline  ley  on  which  the  soap  is  finally  boiled,  is  neces- 
sarily left  entangled  in  the  interstices  of  the  soap,  incompletely 
removed  by  gravitation  whilst  standing ;  so  that  on  analysis  a 
curd  soap  thus  prepared  always  shows  a  considerable  proportion 
of  "  free  alkali."  In  order  to  eliminate  this  an  operation  termed 
"  fitting "  is  carried  out,  more  especially  in  the  case  of  rosin 
(yellow)  soaps,  whereby  a  peculiar  texture  is  attained  as  the 
result.  The  "  made  ""  soap  is  allowed  to  stand  some  twelve 
hours  or  more  so  as  to  bring  about  as  complete  separation  of 


FITTED    AND    MOTTLED    SOAPS.  471 

ley  and  curd  as  possible,  and  the  half  spent  ley  completely 
pumped  away.  Wet  steam  is  then  turned  on,  the  -condensation 
of  which  dilutes  the  ley  still  entangled  in  the  interstices  of  the 
soap  grains.  With  a  particular  stage  of  dilution  (attained  if 
need  be  by  adding  water  to  dilute  further,  or  a  little  stronger 
ley  if  the  dilution  have  gone  too  far)  the  mass  of  soap  acquires 
the  property  of  allowing  a  watery  soap  solution  to  separate  at 
the  bottom  of  the  mass  on  standing  (for  some  days  with  large 
batches,  for  twenty-four  hours  with  smaller  ones),  whilst  the 
rest  of  the  soap  forms  a  mass  of  jelly-like  flakes,  which  solidify 
on  cooling  to  a  yellow  somewhat  waxy  and  translucent  solid, 
usually  containing  a  little  under  30  per  cent,  of  water.  Before 
this  cools,  it  remains  sufficiently  soft  to  allow  all  dirt  and  solid 
impurities,  such  as  coloured  metallic  soaps  (containing  iron,  &c.), 
to  subside  by  gravity,  so  that  the  lowest  watery  stratum  is  very 
dirty  and  much  discoloured,  and  in  consequence  is  known  as  the 
"  negur  "  (sometimes  spelt  negre,  nigre,  nigger,  &c.)  The  upper- 
most layer  of  the  "  neat  soap  "  resting  on  the  negur  generally 
solidifies  whilst  standing  to  a  solid  frothy  crust  known  as  the 
"  fob."  * 

The  character  of  the  "fit"  attained,  whether  "fine"  or 
"coarse,"  is  judged  by  the  indications  observed  on  sampling 
the  mass  from  time  to  time  with  a  trowel  •  when  the  physical 
indications  known  by  experience  to  denote  the  desired  constitu- 
tion of  the  mass  are  observed,  the  boiling  is  stopped,  and  the 
copper  covered  over  to  keep  in  the  heat,  the  whole  being  allowed 
to  stand  at  rest  for  from  two  to  six  days  according  to  the  size  of 
the  batch.  Finally  the  cover  is  removed,  the  fob  carefully  cut 
away,  and  the  still  soft  and  semifluid  neat  soap  pumped  into  the 
frames.  After  cooling,  fitted  soaps  generally  contain  notably 
more  water  than  curd  soaps  :  from  28  to  33  per  cent,  is  usually 
present  in  nonsilicated  genuine  fitted  soaps.  The  fob  is  gener- 
ally worked  up  with  the  next  batch";  the  negur  is  either  worked 
up  with  coarse  fats  and  darker  rosin  and  made  into  a  brown 
rosin  soap,  or  is  utilised  for  making  mottled  soap. 

Mottled  Soaps. — In  the  earlier  half  and  middle  of  the  pre- 
sent century  the  majority  of  soap  manufactured  was  of  the 
curd  class,  and  being  made  from  leys  directly  prepared  from 
black  ash  without  purification,  generally  contained  more  or  less 
sulphide  of  iron,  or  metallic  soaps  disseminated  through  it, 
derived  from  the  impure  liquors,  or  in  some  cases  purposely 
added  (in  the  form  of  raw  or  calcined  green  vitriol  =  ferrous 
sulphate,  &c.)  The  curd  was  boiled  down  until  the  proportion 
of  water  therein  was  reduced  to  a  quantity  not  exceeding  about 

*  Society  has  been  compared  with  a  pot  of  porter,  "dregs  at  foot,  scum  at 
top,  and  good  liquor  in  the  middle  ;"  a  copper  of  fitted  soap  with  "negur  " 
and  "  fob  "  as  the  extremes  and  clean  "  neat  soap  "  in  the  midst,  would  be 
quite  as  apt  a  comparison. 


472  OILS,    FATS,    WAXES,    ETC. 

20  to  23  per  cent.,  and  more  frequently  lying  between  17  and  20 
per  cent. ;  after  standing  and  running  off  the  leys,  the  whole  was 
well  intermixed,  and  the  greyish  or  otherwise  coloured  mass 
run  into  the  frames.  During  cooling  and  solidification  the 
colouring  matters  (chiefly  iron  soap)  segregated  from  the  rest  of 
the  mass  into  veins  ;  so  that  when  the  solid  soap  was  cut  across  a 
peculiar  characteristic  marbling  or  mottling  was  evident.  By 
exposure  to  air  the  iron  soap  changed  its  colour  from  bluish  grey 
to  red  in  consequence  of  oxidation,  forming  what  was  known  in 
the  Marseilles  district  as  the  Manteau  Isabelle.  As  this  effect 
could  not  be  produced  in  the  case  of  a  curd  soap  insufficiently 
boiled  down  (on  account  of  the  thinner  texture  permitting  the 
heavier  metallic  soaps,  &c.,  to  sink  completely  to  the  bottom, 
like  the  negur  of  a  fitted  soap),  the  existence  of  a  mottled  appear- 
ance came  to  be  regarded  as  a  criterion  of  good  quality  so  far  as 
absence  of  an  undue  excess  of  water  (say  not  above  20  per  cent.) 
was  concerned.  "Castile,"  "Marseilles,"  "Olive"  and  other 
mottled  soaps  of  this  class,  although  still  manufactured  to  some 
considerable  extent,  are,  however,  but  little  made  at  the  present 
day  for  household  use  as  compared  with  other  varieties  of 
mottled  soaps  in  which  the  one  especial  good  point  characterising 
the  old  mottled  soaps  is  wholly  absent — viz.,  that  only  a  limited 
amount  of  water  is  present.  A  considerable  degree  of  skill  is 
requisite  in  adjusting  the  proportions  of  materials  used  so  that  a 
maximum  of  water  can  be  incorporated  without  unduly  inter- 
fering with  the  veining  of  the  mass.  Usually  silicate  of  soda 
solution  is  used  as  stiffening  agent,  the  fatty  matters  being 
selected  according  to  the  judgment  of  the  maker,  and  generally 
containing  a  considerable  proportion  of  palm  kernel  oil  or  coker- 
nut  oil,  on  account  of  the  property  of  these  oils  to  form  soda 
soaps  possessing  considerable  stiffness  even  when  largely  watered 
(p.  462).  After  admixture  of  the  silicate  the  pigments  intended 
to  give  the  mottle  are  added,  and  the  mass  thoroughly  crutched 
until  sufficiently  stiffened  to  run  into  the  frames ;  these  are  usually 
made  of  wood  so  as  to  allow  the  mass  to  cool  as  slowly  as  possible 
and  cause  the  mottle  to  "  strike  "  properly  into  veins.  Soaps  thus 
made  and  "  filled  "  with  water  and  silicate  often  contain  50  per 
cent,  and  upwards  of  water  and  not  more  than  40  to  45  per  cent, 
of  actual  soap. 

Absolutely  no  good  purpose  whatever  is  fulfilled  in  com- 
municating a  mottle  of  this  kind  to  household  scouring  soaps  : 
the  only  effect  is  that  the  public  is  induced  to  buy  a  greatly 
inferior  article  on  the  strength  of  the  reputation  for  quality 
gained  years  ago  by  mottled  soaps  of  the  old  style.  Whatever 
advantages  may  be  gained  by  the  addition  of  silicate  as  a  cheap 
detergent,  these  are  wholly  independent  of  the  mottling. 

A  method  of  preparing  hard  soda  soaps  without  employing 
caustic  soda  (sometimes  referred  to  as  the  "old  German  process'') 


ROSIN    SOAPS.  473 

was  formerly  of  considerable  importance,  although  at  the  present 
day  the  relative  prices  of  potash  and  soda  are  such  as  to  render 
the  process  inapplicable,  except  in  backwoods  districts  where 
potashes  are  more  readily  obtainable  than  soda  ash  or  caustic 
soda.  The  tallow,  or  other  mixture  of  fats  and  oils  to  be 
saponified,  is  boiled  up  with  potash  ley  (made  by  causticising 
potashes  with  lime)  much  as  in  the  process  of  soft  soap  making, 
until  a  syrupy  "  close  "  soap  is  obtained  ;  this  is  then  salted  out 
by  the  addition  of  common  salt  or  brine,  whereby  a  curd  is 
obtained  mainly  consisting  of  soda  soap,  the  potash  soap  and 
sodium  chloride  reacting  on  one  another  by  double  decomposition 
(pp.  451,  489).  The  curd  thus  obtained  is  finished  by  repeating 
the  operations  of  boiling  up  with  potash  ley  to  complete  saponifi- 
cation,  and  salting  out  so  as  to  transform  the  majority  of  the 
potash  soap  still  present  into  soda  soap ;  the  curd  ultimately 
obtained  after  a  sufficient  number  of  such  treatments  being 
finally  boiled  up  with  ley  until  any  entangled  salt  is  washed  out, 
whilst  the  ley  becomes  sufficiently  concentrated  for  the  curd  to 
separate  properly. 

In  all  probability,  hard  soda  soaps  were  first  prepared  on  a 
comparatively  large  scale  by  this  kind  of  process,  rather  than  by 
saponitication  with  caustic  soda  direct ;  although  the  use  of 
"  maritime  alkali  "  (barilla)  appears  to  have  been  practised  in  the 
Marseilles  district  as  long  as  the  soap  manufacture  has  existed 
there.  In  inland  districts,  however,  where  seaweed  ash  was 
practically  unattainable,  or  at  any  rate  costly  as  compared  with 
vegetable  potashes,  this  "old  German"  process  was  the  one 
chiefly  employed  for  making  hard  soaps  until  the  discovery  by 
Leblanc  of  the  method  of  preparing  soda  from  common  salt  that 
bears  his  name. 


SPECIAL  VARIETIES  OF  SOAP. 

Rosin  Soaps  (Yellow  Soaps). — In  the  manufacture  of  soaps 
of  this  description  ordinary  rosin  (colophony)  is  used  as  an 
ingredient,  the  mixture  of  alkaline  salts  of  rosin  acids  and  of 
fatty  acids  being  peculiarly  well  adapted  for  certain  purposes. 
In  one  method  of  procedure  (Meinecke's)  crude  turpentine  is 
added  to  the  soap  pan,  which  is  fitted  with  a  still-head,  so  that 
the  spirit  of  turpentine  volatilised  along  with  the  steam  is  con- 
densed and  utilised.  A  much  more  frequently  used  process, 
however,  is  to  separate  the  spirit  and  rosin  by  the  ordinary  dis- 
tillation process,  and  to  mix  the  latter  with  the  fats,  &c.,  to  be 
saponified,  so  that  a  mixture  of  the  alkali  salts  of  fatty  and  resinous 
acids  results  ;  whilst  a  further  improvement  (sometimes  termed 
the  "  French  process  "  for  rosin  soap)  consists  in  dissolving  the 
rosin  in  hot  alkaline  ley  separately  (p.  453),  adding  the  resulting 


474  OILS,    FATS,    WAXES,    ETC. 

resinate  of  soda  solution  to  the  finished  soap,  well  crutching  the 
two  together ;  or  adding  it  to  the  soap  in  the  pan  and  inter- 
mixing by  boiling  up  for  a  few  minutes. 

Rosin  soaps  of  the  better  quality  are  generally  "  fitted " 
(p.  470).  When  made  from  sound  fatty  matters  and  light 
coloured  rosin  ("  windowglass  rosin")  they  possess  a  peculiar 
odour  not  disagreeable,  and  are  known  in  the  south  of  England 
as  "  Primrose "  soap  ;*  such  soaps  usually  contain  about  30  to 
33  per  cent,  of  water  and  66  to  69  per  cent,  of  actual  soap 
(including  resinate  of  soda).  Coarser  rosin  soaps  made  from 
dark  brown  rosin,  damaged  fats,  horsegrease,  and  the  like,  have 
generally  a  more  or  less  marked  unpleasant  animal  odour,  partly 
disguised  by  the  rosin,  or  by  the  addition  of  nitrobenzene  (arti- 
ficial oil  of  almonds,  or  essence  de  mirbane)  or  other  cheap  scents. 
Rosin  soaps  are  generally  preferred  as  stock  soaps  for  trans- 
parent soapmaking  by  the  spirit  process,  as  the  presence  of 
alkaline  resiiiates  facilitates  the  acquisition  and  retention  of  the 
colloid  structure  requisite  for  transparency ;  moreover,  a  well 
fitted  rosin  soap  will  dissolve  practically  completely  in  spirit, 
not  leaving  behind  any  sodium  carbonate  or  other  insoluble 
matters  requiring  separation  by  subsidence  or  filtration.  A 
similar  product  is  also  obtainable  by  dissolving  in  spirit  an 
ordinary  curd  soap  (cut  into  shavings  and  dried)  simultaneously 
with  rosin,  whereby  the  free  alkali  contained  in  the  stock  soap 
is  neutralised,  and  an  alcoholic  solution  of  mixed  fatty  and 
resinous  soaps  directly  obtained. 

The  determination  of  the  relative  amount  of  resinous  acids  and 
fatty  acids  present  in  a  given  sample  of  soap  is  in  many  such 
cases  a  somewhat  important  matter ;  this  may  be  effected  by  the 
methods  described  on  p.  501,  et  seq. 

Silicated  Soaps. — Household  soaps,  properly  socallecl,  consist 
of  the  alkaline  (potash  or  soda)  salts  of  certain  organic  acids, 
either  belonging  to  the  various  fatty  acid  series,  being  derived 
from  natural  oils  and  fats,  or  to  other  series  of  more  feebly, 
marked  acids  derived  from  resins,  more  especially  colophony. 
The  older  soaps  (of  the  first  half  of  the  present  century)  were 
essentially  of  this  character ;  but  a  considerable  proportion  of 
those  now  manufactured  are  cheapened  by  the  admixture  of 
various  ingredients  possessing  more  or  less  marked  detergent 
power,  the  addition  of  which  enables  a  given  weight  of  socallecl 
soap  to  be  manufactured  from  a  greatly  decreased  quantity  of 
fatty  matters.  Of  these  detergent  substances,  obviously  the 
most  natural  constituents  are  the  alkalies  themselves,  either  in 
the  form  of  hydroxides  (caustic  alkalies)  or  as  carbonates  ;  in  the 

*  In  some  districts  in  the  north  of  England  the  term  "primrose''  is 
applied  to  greatly  inferior  articles,  usually  largely  watered  and  treated 
with  silicate  of  soda  to  stiffen  them,  so  that  the  actual  soap  present  consti- 
tutes notably  less  than  one  half  the  mass,  like  the  inferior  mottled  soaps 
described  on  p.  472. 


SILICATED    AND    SULPHATED    SOAPS.  475 

manufacture  of  "oil"  soaps  (oleic  acid  soaps,  p.  452)  these  con- 
stituents are  introduced  by  the  simple  process  of  using  a  larger 
quantity  of  alkaline  ley  than  is  equivalent  to  the  fatty  acids  ;  in 
other  cases,  the  alkalies  are  dissolved  in  water  and  crutched  into 
the  soap  before  framing.  The  introduction  of  silicate  of  soda 
solution  has  various  advantages  as  compared  with  that  of  caustic 
alkalies,  proper  incorporation  being  more  easy ;  whilst  for  such 
purposes  as  scouring  floors,  &c.,  the  increased  detergence  thereby 
gained  is  distinctly  advantageous.  For  laundry  soaps,  on  the 
other  hand,  the  utility  of  silicates  is  far  less  manifest ;  so  much 
so,  that  various  much  advertised  laundry  soaps  of  the  present  day 
are  purposely  prepared  without  that  ingredient  (sodium  carbonate 
being  in  some  cases  used  instead) ;  to  which  circumstances  they 
largely  owe  what  superiority  they  may  possess  over  other  silicated 
soaps. 

One  notable  advantage  gained  by  the  admixture  of  silicate  of 
soda  with  soaps  made  from  cheap  soft  fats,  &c.,  is  that  the  texture 
of  the  bar  of  soap  is  considerably  stiffened  and  hardened,  so  that 
the  soap  does  not  waste  so  rapidly  in  hot  water  or  when  rubbed 
against  the  clothing,  tfec.,  to  be  washed,  as  it  otherwise  would 
necessarily  do. 

Normandy  Soaps  (Sulphated  Soaps). — In  order  to  harden 
and  stiffen  a  comparatively  soft  soap  mass  various  neutral  salts 
may  also  be  employed,  more  especially  sodium  sulphate  or  thio- 
sulphate.  The  use  of  these  stiffening  agents  was  originally 
introduced  by  Dr.  Normandy,  not  for  purposes  of  adulteration 
or  "filling,"  but  in  order  to  enable  useful  household  scouring 
soaps  to  be  made  from  materials  that  otherwise  would  give  a 
product  too  soft  for  economical  use  in  scrubbing,  especially  with 
hot  water.  When  sodium  sulphate  (Glauber's  salt)  was  used, 
the  crystallised  salt  (not  salt  cake)  was  heated  so  as  to  fuse  in 
its  own  water  of  crystallisation,*  the  liquid  being  immediately 
crutched  into  the  hot  soap  ;  from  one-fifth  to  one-third  of  the 
weight  of  the  soap  being  thus  added.  The  soaps  thus  made 
rapidly  become  unsightly  through  efflorescence ;  so  that  their 
use  at  the  present  day  is  not  large,  other  stiffening  agents  (more 
especially  alkaline  carbonates  and  sodium  silicate)  being  pre- 
ferred. 

Aluminated  Soaps. — Aluminate  of  soda  has  been  proposed, 
and  to  some  extent  used,  as  a  substitute  for  silicate  of  soda  in 
the  preparation  of  scouring  soaps,  for  which  purpose  it  does  not 
seem  to  have  any  special  advantages  or  marked  disadvantages. 

Borax  Soaps. — The  addition  of  borax  to  laundry  soaps  is 
sometimes  made,  that  salt  possessing  considerable  detergent 
power  without  injurious  action  on  textile  fibres  j  it  is  usually 

*  If  salt  cake  is  used,  it  must  be  dissolved  in  the  right  quantity  of  water 
and  treated  with  a  little  soda  ash,  so  as  to  neutralise  the  free  acid  present 
and  precipitate  the  ferric  oxide  contained  as  sulphate. 


476  OILS,    FATS,    WAXES,    ETC. 

supposed,  moreover,  to  have  a  special  blanching  action  on  linen. 
Some  socalled  "  borax  soaps,"  however,  are  in  the  market  that 
contain  only  extremely  minute  amounts  of  borax,  or  none  at  all. 

Phosphated  Soaps. — In  order  to  diminish  the  waste  of  soap 
with  hard  water  through  double  decomposition  by  the  lime  and 
magnesia  salts  present,  H.  Grimshaw*  adds  an  alkaline  phosphate 
to  the  soap,  with  the  object  of  forming  calcium  and  magnesium 
phosphates  instead  of  lime  and  magnesia  soaps  insoluble  in  water. 

Paraffin  Oil  and  Petroleum  Soaps. — Hydrocarbons  of  the 
paraffin  series  possess  the  physical  property  of  forming  jellies 
when  admixed  with  soap  solutions  under  suitable  circum- 
stances ;  a  small  quantity  of  soap  will  thus  solidify  a  large 
quantity  of  hydrocarbon,  a  circumstance  taken  advantage  of  in 
manufacturing  "  solidified  petroleum "  for  fuel.  On  the  other 
hand,  10  or  20  per  cent,  of  such  oil  can  be  crutched  into  a  hot 
soap  paste  without  materially  interfering  with  its  setting  on 
cooling,  so  that  a  large  amount  of  "loading"  may  be  thus  effected. 
With  certain  kinds  of  transparent  soap  (made  by  the  cold  process, 
pp.  458,  482)  this  addition  is  frequently  made. 

For  laundry  purposes  the  diluting  effect  of  the  hydrocarbon 
oils  is  more  or  less  compensated  by  an  increased  detergent  action : 
greasy  linen,  &c.,  soaped  with  "paraffin  soap"  can  often  be  cleansed 
with  less  rubbing  and  friction  than  would  otherwise  be  necessary 
because  the  hydrocarbon  tends  to  dissolve  the  grease  and  so  to 
facilitate  the  detergent  action  of  the  soap  so  far  as  other  dirt  is 
concerned. 

Sand,  Puller's  Earth,  Pipeclay,  Kaolin,  and  Brickdust 
Soaps. — When  soap  is  required  for  household  or  other  cleansing 
purposes  to  be  used  in  conjunction  with  fuller's  earth,  powdered 
brickdust  or  pumicestone,  sand,  emery,  or  such  like  materials  so 
as  to  brighten  metallic  surfaces,  cleanse  greasy  paint  (insides  of 
baths,  &c.),  and  so  on,  it  is  often  found  convenient  to  prepare 
blocks  of  mixed  mineral  powder  and  soap  for  sale ;  these  are 
made  by  crutching  the  pulverised  pumicestone,  &c.,  into  the 
hot  melted  soap  in  as  large  a  proportion  as  is  consistent  with  its 
sticking  together  in  blocks  when  cold,  and  are  then  sold  under 
various  proprietary  names,  chosen  according  to  the  fancy  of  the 
maker.  For  general  cleansing  purposes  such  mixtures  are  often 
very  handy;  but  the  price  charged,  although  moderate  enough  as 
regards  the  weight  of  the  block  as  a  whole,  is  generally  high 
with  respect  to  the  quantity  of  soap  actually  present  therein. 
Superior  kinds  of  such  soaps  are  sometimes  sold  as  "tooth  soaps," 
prepared  by  incorporating  with  a  good  kind  of  remelted  toilet  soap 
some  10  to  20  per  cent,  of  finely  powdered  marble  or  pumice- 
stone, cuttlefish  bone,  prepared  chalk,  &c.,  &c. 

Disinfectant   Soaps. —A  large  variety  of  soaps  are  in  the 
market  consisting  of  ordinary  soaps  of  more  or  less  good  quality 
*  English  Patent,  No.  983,  1890. 


COLDWATKR    SOAPS.  477 

into  which  have  been  crutched,  before  finally  cooling  and 
solidifying,  fluid  or  other  disinfecting  materials,  more  espe- 
cially those  derived  from  coaltar  products — e.g.,  carbolic  and 
cresylic  acids,  naphthol,  naphthalene  and  creosote  oils,  &c.  ;  or 
the  artificial  camphoraceous  products  got  by  the  oxidation  of  oil 
of  turpentine  (Sanitas  oil)  ;  or  hydrocarbons,  such  as  terebene ; 
or  various  inorganic  germicide  materials.  Of  these  different 
products,  a  considerable  number  are  highly  valuable  for  the 
particular  purposes  for  which  they  are  intended  ;  but  the  value 
of  others  is,  at  the  best,  only  small  as  antiseptic  and  disinfectant 
agents. 

To  this  category  also  belong  a  variety  of  "  medicinal "  soaps, 
usually  put  up  in  tablet  form  like  "toilet"  soaps  (p.  478);  in 
these  a  stock  soap  of  more  or  less  good  quality  forms  the  basis, 
sulphur,  iodine,  ichthyol,  mercurial  preparations,  or  other  medi- 
caments, supposed  to  exert  beneficial  action  in  certain  cases  when 
thus  applied  to  the  skin,  being  mixed  in  either  by  remelting  or 
milling,  or  in  some  cases  being  added  to  the  mass  formed  by  the 
cold  process  before  it  finally  solidities. 

Coldwater  Soaps. — Various  soaps  are  sold  under  this  name, 
the  alleged  advantage  of  which  is  usually  stated  to  be  that  they 
will  lather  freely  with  cold  water  and  therefore  do  not  require 
clothes,  etc.,  to  be  boiled.  In  many  cases  a  more  accurate 
description  wrould  be  that  they  dissolve  so  freely  in  hot  water  as 
to  be  highly  wasteful  when  used  therewith.  They  generally 
consist  of  more  or  less  watered  soaps  *  containing  cokernut  or 
palm  kernel  oil  to  give  consistency,  with  a  liberal  intermixture  of 
potassium  or  sodium  carbonate  (less  frequently  of  silicate)  to 
harden  and  give  increased  detergent  action  ;  in  practice  they  are 
equivalent  to  a  mixture  of  'true  soap  and  soda  crystals,  and  like 
sand  and  brickdust  soaps  they  are  accordingly  very  handy  in 
use  ;  but  in  general  the  price  is  high  .as  compared  with  the  actual 
amount  of  soap  present. 

Soap  Powders. — The  above  remark  applies  a  fortiori  to  these 
substances  which  in  general  consist  of  ground-up  soda  crystals 
(sometimes  of  ordinary  soda  ash)  with  more  or  less  pulverised 
dry  soap  intermixed ;  they  are  usually  highly  efficacious  as  deter- 
gents, but  somewhat  dear  as  compared  with  the  value  of  the 
alkali  present  and  the  soap,  taken  separately  from  the  water  of 
crystallisation  and  other  inert  constituents. 

Starch  Soaps,  Oatmeal  Soap,  &c. — More  than  one  patent 
has  been  taken  out  for  the  preparation  of  products  where  potato 
jiour,  starch,  and  similar  materials  are  intermixed  with  ordinary 

*  Some  few  "cold  water1'  soaps  do  not  contain  more  than  20  to  25  per 
cent,  of  water,  and  are  made  with  only  comparatively  small  additions  of 
potassium  or  sodium  carbonate,  the  former  being  preferably  used  to  soften 
the  texture,  a  result  also  partly  brought  about  by  the  use  of  semidrying  oils 
as  ingredients — e.g.,  cotton  seed  oil. 


478  OILS,    FATS,    WAXES,    ETC. 

soaps.  The  advantages  of  such  mixtures  are  difficult  to  under- 
stand. Oatmeal,  however,  well  intermixed  with  some  reasonably 
good  quality  of  stock  soap,  enjoys  some  degree  of  popularity  as  a 
"skinsoap."  Bran  and  gluten  have  been  used  for  the  same 
purpose  ;  as  also  dextrine,  Iceland  moss  and  other  lichen  jellies, 
sawdust,  cornflour,  and  various  analogous  substances. 


TOILET  AND  FANCY  SOAPS. 

The  term  "  toilet  soap "  is  generally  supposed  to  denote  a 
superfine  variety  of  soap  specially  prepared  with  the  object  not 
only  of  effecting  cleansing  during  ablution,  but  of  doing  this 
in  the  most  delicate  way  with  regard  to  injurious  action  on  the 
skin,  thus  serving  as  a  sort  of  cosmetic.  Some  of  the  socalled 
toilet  soaps  in  the  market  well  fulfil  this  description  ;  but, 
unfortunately,  many  others  are  largely  advertised  and  sold  which 
are  of  a  far  less  satisfactory  character,  either  through  imperfections 
of  manufacture  (more  especially  presence  of  excess  of  alkali),  or 
because  of  their  having  an  objectionable  action  on  tender  skins, 
through  admixture  of  other  ingredients  (particularly  cane  sugar). 

Some  varieties  of  socalled  toilet  soaps  are  simply  household 
soaps  of  the  finer  class,  more  especially  curd  and  yellow  soaps 
made  from  first  class  materials,  cut  up  into  tablets,  and  stamped 
into  shape  by  one  or  other  of  the  various  kinds  of  stamping 
press  referred  to  on  p.  444.  As  a  rule  these  are  scentless,  but 
sometimes  a  small  proportion  of  cheap  essential  oil  or  other 
perfume  (such  as  citronella,  mirbane,  &c.)  is  crutched  in  before 
framing. 

More  frequently  stock  soaps  of  good  quality  are  prepared  on 
the  large  scale  from  choice,  or  at  least  sound,  materials,  and 
are  then  cut  up,  intermixed  or  blended,  remelted,  and  again 
framed,  working  on  a  smaller  scale  :  usually  scenting  materials 
are  introduced  just  before  transferring  to  the  frames,  and  in 
some  cases  emollient  ingredients  or  unguents — e.g.,  lanolin,  vase- 
line, beeswax,  spermaceti,  or  various  undecomposed  glycerides, 
such  as  the  finest  beef  marrow,  lard,  the  socalled  "  beef  stearine  " 
separated  from  the  more  fusible  fats  in  the  manufacture  of  mar- 
garine (p.  309),  «kc.  Of  late  years  "superfatted"  soaps  of  this 
description  (in  some  cases  made  by  remelting,  in  others  by 
milling  —  vide  infra)  have  been  somewhat  largely  "boomed," 
the  special  advantage  derived  from  their  use  being  supposed  to 
be  that  an  extremely  thin  greasy  film  adheres  to  the  skin  after 
use,  which  more  or  less  prevents  the  drying  and  chapping 
action  otherwise  produced  by  ordinary  soaps  on  tender  skins. 
Opinions  differ  widely  as  to  how  far  this  alleged  advantage  is 
really  gained  or  not,  some  regarding  the  presence  of  a  few 
per  cents,  of  glycerides  in  the  soap  as  actually  furnishing  a 


TOILET    AND    FANCY    SOAPS.  479 

protective  film  of  the  kind,  rendering  the  outer  layer  of  the 
skin  soft  and  supple  ;  whilst  others  consider  that  inasmuch  as 
the  action  of  water  on  perfectly  neutral  soap  always  liberates 
more  or  less  free  alkali,  which  emulsifies  grease  and  enables  it 
to  be  washed  off,  whilst  any  excess  of  alkali  naturally  contained 
in  the  soap  accelerates  the  action,  the  notion  .of  an  adherent 
protective  grease  film  is  a  priori  improbable  ;  the  advantage  of 
such  soaps  lying  rather  in  their  freedom  from  excess  of  alkali 
arid  other  objectionable  skin  roughening  substances  such  as. 
sugar.  On  the  whole,  the  preponderance  of  opinion  rather 
seems  to  be  in  the  direction  of  regarding  nonglyceridic  un- 
guents (lanolin,  spermaceti,  etc.)  as  being  more  "  emollient ;> 
when  thus  admixed  with  soap  than  glyceridic  materials  such 
as  usually  found  in  "superfatted"  soaps — i.e.,  when  all  other 
things  are  equal,  especially  absence  of  free  alkali  ;  moreover, 
the  presence  of  unsaponified  fatty  matters  seems  sometimes  to- 
facilitate  discoloration  on  keeping  through  the  development  of  a, 
kind  of  rancidity. 

In  some  cases  "pearlashing"  (pp.  451,  489)  is  adopted  to  improve 
the  texture  and  lathering  power ;  when  this  is  done  the  pearlash 
liquor  (solution  of  potassium  carbonate)  is  simply  crutched  in 
with  the  other  ingredients  before  framing.  Since  an  equivalent 
of  sodium  carbonate  is  formed  for  one  of  potassium  carbonate 
introduced,  obviously,  a  pearlashed  soap  is  apt  to  be  strongly 
alkaline  and  objectionable  for  persons  suffering  from  tender 
skins,  or  a  tendency  to  acne  or  eczema. 

Milled  Soaps. — "Perfumers'  soaps,"  sometimes  known  as. 
"  little-pan  soaps,"  were  formerly  largely  made  by  perfumers  by 
means  of  the  cold  process.  The  fatty  matters  thus  employed 
were  generally  of  excellent  quality,  being  mainly  the  oils  and 
fatty  cakes  used  to  absorb  flower  perfume  (odorous  essential 
oils)  by  packing  the  fat  cakes  and  flower  petals  together,  or  by 
passing  air  over  the  flowers  and  bringing  it  in  contact  with  oil, 
etc.,  to  absorb  the  volatile  odorous  matter;  after  the  oil  or  fat 
was  fully  charged  by  numerous  repetitions  of  the  process  it  was 
treated  with  alcohol,  whereby  a  flower  essence  was  obtained  by 
dissolving  out  the  essential  oils,  leaving  behind  a  delicately 
scented  fat,  capable  of  furnishing  a  deliciously  perfumed  soap. 
Owing,  however,  to  the  necessity  for  avoiding  heat  as  much 
as  possible  in  the  preparation  of  the  soap,  it  often  happened 
that  these  soaps  contained  simultaneously  much  undecomposed 
fat  and  a  large  amount  of  free  alkali.  Accordingly,  of  late  years 
they  have  been  largely  supplanted  by  "milled"  soaps,  where 
stock  soaps  of  good  quality  are  "  stripped  "  or  reduced  to  chips 
and  dried  until  only  a  few  per  cents,  of  moisture  are  retained, 
and  then  ground  (together  ^  with  perfumes,  colouring  matters, 
glycerine,  or  other  emollient  ingredients,  etc.,  as  required)  be- 
tween rollers  until  reduced  to  a  stiff  putty-like  mass,  which  is 


480  OILS,    FATS,    WAXES,    ETC. 

then  squirted  or  screwed  into  bars  and  so  formed  into  tablets 
(p.  448).  The  advantages  of  this  method  are,  firstly,  that  inas- 
much as  no  artificial  heat  is  applied,  delicate  flower  perfumes,  &c., 
can  be  readily  incorporated  with  the  soap  mass,  which  it  would 
be  impossible  to  use  with  a  remelted  soap  because  the  heat 
would  dissipate  or  destroy  the  odorous  matter;  and  secondly, 
that  as  the  resulting  tablets  usually  contain  only  a  small  quantity 
of  water,  a  given  weight  of  soap  tablet  generally  contains  a  much 
larger  quantity  of  actual  soap  than  another  tablet  of  the  same 
weight  prepared  by  remelting  or  by  the  cold  process,  whilst, 
being  harder  and  stiffer,  it  lasts  longer,  wasting  less  rapidly 
during  use.  By  suitably  choosing  the  stock  soaps  used,  em- 
ploying only  such  as  have  been  prepared  from  first  class  oils  and 
fats,  etc.,  and  refined  or  otherwise  treated  to  remove  "  free " 
alkaline  matters,  "fancy"  and  "toilet"  soaps  of  the  finest  possible 
qualities  are  thus  readily  obtainable.  Frequently  the  stock  soaps 
are  partly  made  with  potash  and  partly  with  soda,  so  as  to  arrive 
at  a  suitable  texture  through  the  softer  nature  of  the  potash  soap, 
as  well  as  to  produce  a  better  lather. 

In  this  connection  it  is  worth  noticing  that  there  is  some 
reason  for  supposing  that  soap  with  which  an  extremely  large 
proportion  of  flower  essences  and  essential  oils  is  incorporated, 
may  thereby  become  less  suitable  for  use  by  persons  suffering 
from  tender  skins  than  would  be  the  case  with  a  lessened  amount 
of  odorous  matter,  inasmuch  as  many  essential  oils  of  the  kind 
possess  more  or  less  marked  rubefacient  (skin-reddening)  action, 
analogous  in  character  to  the  stimulating  and  blistering  action  of 
mustard,  oil  of  turpentine,  and  similar  substances.  It  is  within 
the  author's  own  personal  observation  that  when  the  same  high- 
class  soap  mass  is  used  for  preparing  two  differently  priced  fancy 
soaps,  only  differing  in  that  the  more  expensive  one  is  impregnated 
with  a  much  larger  proportion  of  scent  than  the  other,  persons 
possessing  exceptionally  sensitive  skins  can  sometimes  use  tablets 
made  from  the  less  highly  scented  portion  with  impunity,  whilst 
the  employment  of  tablets  made  from  the  more  strongly  per- 
fumed portion  speedily  sets  up  a  disagreeable  amount  of  skin 
irritation. 

From  the  point  of  view  of  irritating  skin  action,  however,  the 
presence  of  sugar  appears  to  be  much  more  objectionable  than 
that  of  most  scenting  materials,  even  in  large  quantity.  Opaque 
fancy  soaps  are  rarely,  if  ever,  admixed  with  this  adulterant ; 
but  very  little  transparent  soap  is  in  the  market  that  does  not 
contain  more  or  less. 

Brown  Windsor  Soap. — The  term  "  Brown  Windsor "  has 
long  been  applied  to  a  peculiar  brown  soap  highly  esteemed  for 
toilet  purposes.  Originally  this  substance  deserved  its  reputation ; 
but  as  in  the  case  of  "mottled"  soap,  the  perverted  ingenuity  of  the 
modern  adulterator  has  completely  altered  the  character  of  the 


TRANSPARENT    SOAPS.  481 

great  majority  of  toilet  tablets  sold  under  that  name.  The  "  Old 
Brown.  Windsor  "  of  a  generation  or  two  back  was  simply  a  form 
of  soap  (usually  mostly  curd)  that  had  been  kept  in  stock  for  a 
great  length  of  time,  and  occasionally  remelted ;  with  the 
result  of  acquiring  a  pretty  deep  brown  tint  through  oxidation 
of  fatty  acids,  &c.,  and  of  becoming  practically  wholly  devoid 
of  free  alkali,  any  excess  of  alkali  originally  present  being 
neutralised  by  the  weakly  acid  oxidation  products  formed 
during  keeping  or  "  ageing,"  or  whilst  being  remelted.  Such  a 
soap,  pleasantly  scented  at  the  last  remelting  before  making  into 
tablets,  and  originally  made  from  suitable  materials,  lathered 
sufficiently  freely  to  be  conveniently  used,  and  had  as  little 
deleterious  action  on  sensitive  skins  as  is  compatible  with  the 
hydrolytic  properties  of  soaps  generally.  The  modern  substitutes, 
however,  are  frequently  nothing  but  coarse  soaps  made  from  dis- 
coloured fats,  and  further  browned  by  coaltar  dyes  or  admixture 
of  brown  ochre  :  all  sorts  of  scraps  (including  floor  scrapings) 
incapable  of  utilisation  in  any  other  way  are  worked  into  the 
mass,  which  frequently  is  alkaline  to  a  highly  objectionable 
extent.  In  short,  advantage  is  taken  of  the  reputation  deservedly 
gained  in  former  years  by  an  excellent  article  to  sell  under  the 
same  name  an  eminently  inferior  product.  Similarly,  socalled 
"  White  Windsor "  soaps  are  sometimes  to  be  met  with,  largely 
made  from  cokernut  oil,  highly  alkaline,  and  wholly  different  in 
character  from  the  genuine  old  fashioned  brown  article. 

Transparent  Soaps. — As  already  stated,  soap  can  in  many 
cases  assume  two  distinct  physical  conditions,  one  a  more  or  less 
distinctly  crystalline  form  in  which  the  "grains"  retain  associated 
by  a  sort  of  physical  attraction  a  considerable  quantity  of  water, 
the  amount  of  which  varies  with  circumstances — e.g.,  a  curd  soap, 
when  granulated  from  a  dilute  liquor  with  a  minimum  of  salt  or 
alkali,  will  contain  as  much  as  35  to  40  per  cent,  of  such  associated 
water,  which  becomes  gradually  lessened  down  to  20  to  25  per 
cent,  or  less  by  boiling  down  with  dry  steam  or  free  fire  so  as  to 
concentrate  the  leys.  The  other  is  a  structureless  colloidal  state, 
constituting  a  mass  which  under  suitable  conditions  is  clear  and 
transparent  like  a  strong  jelly.  Soft  soaps  (potash  soaps)  appear 
to  have  a  stronger  tendency  to  retain  this  colloidal  state  than 
hard  (soda)  soaps,  so  that  it  is  only  with  comparative  difficulty 
that  they  become  granular ;  soda  soaps,  on  the  other  hand, 
although  granular  when  separated  from  watery  solutions  by 
means  of  salt,  readily  become  colloidal  when  dissolved  in  alcohol, 
so  as  to  form  transparent  masses  when  the  solvent  evaporates. 
This  physical  condition  is  facilitated  in  many  cases  by  the  presence 
of  various  other  substances,  of  which  glycerol  is  one  of  the  best 
known ;  so  that  fats  saponified  by  the  cold  process,  even  in  the 
absence  of  alcohol,  often  yield  transparent  products  owing  to 
the  production  of  glycerol  during  the  process.  Castor  oil,  in 

31 


482  OILS,    FATS,    WAXES,    ETC. 

particular,  readily  yields  a  transparent  product  in  this  way. 
Cane  sugar  possesses  the  same  property ;  and  being  cheaper  and 
easier  to  work  with  in  some  respects,  is  largely  substituted  for 
glycerol,  to  the  great  disadvantage  of  the  consumer,  excepting  in 
one  respect,  viz.,  that  whilst  transparent  soaps  containing  large 
percentages  of  glycerol  are  apt  to  "  sweat,"  by  attracting  moisture 
from  the  air,  sugared  soaps  do  not  deliquesce  so  markedly. 
Resinates  mixed  with  ordinary  fatty  acid  soaps  generally  form 
colloidal  masses  more  readily  than  the  latter  alone  ;  accordingly, 
rosin  soaps  are  preferred  as  "  stock  "  when  granular  soaps  are  to 
be  rendered  transparent.  This  tendency  to  transparency  is  often 
strongly  marked  even  with  water-made  rosin  soaps  of  good  quality 
("fitted"  soaps),  which  generally  become  translucent  and  some- 
times tolerably  clear  when  spontaneously  dried  in  not  too  thick 
masses. 

Accordingly,  two  principal  methods  are  in  use  for  the  prepar- 
ation of  transparent  soaps.  In  the  "spirit"  process  the  stock 
soap  is  dissolved  in  spirit  and  treated  as  described  (p.  445),  rosin 
being  sometimes  added  to  the  mass  for  the  double  purpose  of 
aiding  transparency  and  combining  with  free  alkali  so  as  to 
neutralise  it.*  The  mass  left  when  the  bulk  of  the  spirit  is 
distilled  off  is  usually  turbid ;  but  on  slow  drying  in  a  warm 
storage  room  (temperature  near  35°  C.  =  95°  F.)  it  becomes  clear, 
especially  when  a  liberal  addition  of  sugar  has  been  made  to  the 
mass  before  finally  casting  in  the  frames.  Usually  the  blocks 
are  cut  up  into  tablets  which  are  shaped  by  stamping  in  blank 
dies,  and  then  slowly  dried,  the  final  impression  being  given  by 
a  later  stamping.  When  glycerol  is  added  instead  of  sugar,  the 
resulting  transparent  soap  is  as  innocuous,  even  to  the  most 
sensitive  skin,  as  any  kind  of  soap  can  possibly  be  ;  but  the  same 
can  by  no  means  be  said  of  sugared  soaps  (which  constitute  the 
large  majority  of  those  in  the  market),  persons  of  unusually 
tender  skins  being  generally  unable  to  use  such  compositions 
long  without  suffering  more  or  less  severely  in  consequence. 

Similar  remarks  apply  to  the  transparent  soaps  made  by  the 
other  process  (cold  process,  p.  458) ;  when  sound  fatty  and  oily 
matters  are  used,  together  with  alkali  not  in  excess,  no  sugar 
being  employed,  an  article  results  of  superior  kind ;  but  the 
great  bulk  of  socalled  "  glycerine  "  soap  made  in  this  way  is 
alkaline  to  an  extent  highly  prejudicial  to  tender  skins,  besides 
being  largely  admixed  with  sugar,  f  whilst  in  many  cases  the  oils 
used  (chiefly  castor  oil,  together  with  cokernut  oil,  &c.)  are  of 
such  quality  as  to  leave  an  unpleasant  odour  on  the  skin,  easily 

*  Some  transparent  soaps  thus  prepared  when  dissolved  in  water  and 
agitated  with  petroleum  spirit,  or  when  dried  and  percolated  therewith  in 
a  Soxhlet  tube,  will  yield  several  per  cents,  of  uncombined  colophony  to  the 
solvent. 

t  For  a  typical  analysis  of  a  soap  of  this  kind  (not  loaded  with  hydro- 
carbons) vide  p.  511. 


NEUTRALISED    SOAPS.  483 

perceptible  when  the  scenting  material  has  evaporated  •  and  in 
addition,  large  percentages  of  valueless  "  loading "  (petroleum 
hydrocarbons,  £c.)  are  added  to  increase  the  weight.  In  short, 
transparent  toilet  soaps,  like  artificially  mottled  scouring  soaps, 
are  articles  in  the  purchase  of  which  caution  is  pre-eminently 
desirable.  For  further  details  concerning  transparent  and  other 
toilet  soaps  and  their  manufacture,  vide  the  author's  "  Cantor 
Lectures  on  the  Manufacture  of  Toilet  Soaps  "  (Journal  Society  of 
Arts,  1885). 

Soap  Leaves. — A  very  convenient  form  of  soap  for  travellers 
is  obtained  by  melting  a  good  quality  of  stock  soap  with  a  little 
water,  perfuming  to  taste,  and  passing  sheets  of  tissue  paper 
through  the  fluid;  the  paper  thus  filmed  with  soap  is  dried  and 
cut  up  into  leaves,  one  of  which  generally  suffices  for  ordinary 
washing  of  the  hands,  &c.,  thus  avoiding  the  necessity  of  having 
to  carry  about  a  wet  cake  of  soap. 

Marbled  Soaps  and  Harlequin  Soaps. — A  peculiar  marbled 
appearance  is  sometimes  given  to  soap  balls,  tablets,  &c.,  by 
remelting  a  more  or  less  white  stock  soap,  and  running 'it  into  a 
small  frame ;  a  comb  with  wide  teeth  is  then  dipped  into  a 
colouring  composition  (melted  soap  with  pigments  or  dissolved 
colouring  matters),  withdrawn,  and  passed  through  the  semifluid 
soap  in  the  frame,  so  as  to  streak  it  according  to  fancy.  The 
same  method  is  applicable  to  cold  process  compositions,  before 
they  have  completely  solidified.  By  cutting  up  pieces  of  variously 
tinted  soaps  into  fragments,  and  scattering  them  through  a  cold 
process  transparent  soap  mass  on  the  point  of  solidifying,  a 
mixture  of  transparent  soap  with  variously  tinted  lumps  inter- 
spersed is  ultimately  obtained  ;  when  cut  up  and  stamped  into 
tablets,  these  are  sometimes  sold  as  "  harlequin  soaps."  Tablets 
are  sometimes  ornamented  by  stamping  a  device  somewhat 
deeply,  and  then  filling  the  grooves  with  melted  coloured  trans- 
parent soap,  &c. 

Shaving  Creams. — Cold  process  soaps  made  from  refined  lard 
or  other  superfine  fatty  matters  and  caustic  potash,  not  used  in 
excess,  are  usually  the  basis  of  these  preparations ;  to  facilitate 
lathering,  a  small  quantity  of  the  finest  cokernut  oil  is  often 
added.  The  resulting  mass  is  ultimately  ground  in  a  marble 
mortar,  <fcc.,  with  scenting  materials  (oil  of  bitter  almonds  for 
almond  cream,  and  so  on),  glycerol  or  other  emollient  ingredients 
being  added  to  taste,  and  sometimes  tinting  materials — e.g.,  a  few 
grains  of  vermilion  per  Ib. — to  give  a  faint  flesh  colour,  &c.  A 
perfumed  concentrated  alcoholic  solution  of  soap  forms  a  variety 
sometimes  known  as  "  liquid  soap." 

Neutralised  Soaps. — For  certain  special  purposes  it  is  highly 
important  that  the  soapr  employed  should  be  as  devoid  of  free 
alkali  as  possible.  In  order  to  effect  this  object  a  variety  of 
methods  have  been  proposed  and  more  or  less  largely  employed, 


484  OILS,    FATS,    WAXES,    ETC. 

according  to  circumstances.  In  the  generality  of  cases  soaps 
that  have  been  put  through  the  operation  of  "fitting"  (p.  470) 
are  almost  absolutely  neutral,  any  entangled  alkaline  ley  present 
in  the  curd  before  fitting  having  been  washed  out  during  the 
process  ;  if,  however,  after  "  cleansing "  in  this  way  so  as  to 
separate  coloured  impurities,  the  soap  be  again  boiled  down  on  a 
fresh  portion  of  ley,  the  resulting  curd  soap  is  always  consider- 
ably alkaline  through  entangled  ley.  A  method  used  with  some 
degree  of  success  consists  in  remelting  (p.  441)  the  soap  to  be 
treated  with  a  small  proportion  of  fatty  matter  which  becomes 
more  or  less  saponified  by  the  treatment ;  inasmuch,  however,  as 
the  alkali  present  is  generally  carbonated,  this  method  rarely 
gets  rid  of  all  the  free  alkali,  excepting  in  cases  where  the  addi- 
tional fatty  matters  used  consist  largely  of  free  fatty  acids  like 
some  kinds  of  largely  hydrolysed  palm  oil.*  In  the  manufacture  of 
transparent  toilet  soaps  by  the  spirit  process,  any  carbonated 
alkali  present  is  left  undissolved  and  is,  consequently,  separated 
by  subsidence  or  straining ;  whilst  if  rosin  be  directly  added,  the 
free  alkali  present  is  more  or  less  converted  into  resinate  and  so 
eliminated.  When,  however,  resinous  or  fatty  materials  are 
added  to  a  soap  mass  in  the  milling  process,  no  action  ensues 
between  them  and  the  free  alkali ;  so  that  "  superfatted  "  soaps 
thus  prepared  (without  long  continued  fusion  of  the  glycerides 
with  the  soap  by  remelting)  often  contain  simultaneously  excess  of 
alkali  and  unsaponified  glycerides,  like  imperfectly  made  cold  pro- 
cess soap  (p.  457).  The  author's  ammonium  salt  process,  referred 
to  on  p.  453,  on  the  other  hand,  acts  equally  well  in  the  way  of 
removing  "free  "  alkali,  whether  applied  to  soap  shavings  during 
the  milling  process,  or  to  fused  soap  during  remelting,  or  to  soap 
curd,  &c.,  in  the  crutching  pan;  any  alkaline  carbonate  or 
hydroxide  being  converted  into  a  neutral  salt  with  simultaneous 
evolution  of  ammonia  which  mostly  escapes. 


CHAPTER   XXL 
GENERAL  CHEMISTRY  OF  SOAP— SOAP  ANALYSIS. 

IN  addition  to  various  points  previously  discussed  in  connection 
with  the  general  chemical  and  physical  properties  of  oils,  &c.,  a 
variety  of  other  matters  are  of  some  interest  relating  to  the 
properties  of  soaps  of  various  kinds. 

*  According  to  A.  Watts,  the  superiority  of  the  madder  purples  for  which 
the  firm  of  lloyle  &  Sons  were  long  famous,  was  due  to  their  practice  of 
remelting  the  best  soaps  procurable  with  an  additional  quantity  of  palm 
oil. 


CHEMISTRY    OP    SOAPS.  485 

As  already  explained,  what  is  ordinarily  meant  by  the  term 
"soap"  is  simply  the  various  substances  obtainable  consisting 
of  the  alkaline  (potash  and  soda)  salts  of  the  various  fatty  acids 
contained  as  glycerides  in  oils  and  fats,  and  of  the  rosin  acids 
contained  in  colophony  and  allied  resinous  matters.  Numerous 
corresponding  salts  of  the  alkaline  earths  and  heavy  metals, 
however,  exist,  all  of  which,  strictly  speaking,  are  also  soaps  — 
e.g.,  the  lime  "rock"  obtained  in  the  manufacture  of  candle 
stearine  (pp.  365,  373),  and  the  "lead  plaster"  obtained  by  mixing 
together  olive  oil  (or  other  analogous  oil)  and  litharge.  As  a 
general  rule  these  earthy  and  metallic  soaps  are  insoluble  in 
water,  at  any  rate  as  compared  with  alkali  soaps  ;  so  that  on 
adding  a  metallic  salt  solution  to  an  aqueous  solution  of  alkali 
soap,  double  decomposition  occurs,  and  a  precipitate  is  formed  of 
the  metallic  soap.  Thus,  for  example,  the  applicability  of  Clark's 
soap  test  for  lime  and  magnesia  in  water  depends  on  such 
actions  —  e.g.,  in  the  case  of  stearates  — 

Sodium  Stearate.  Calcium  Sulphate.          Calcium  Stearate.  Sodium  Sulphate. 

2Na  .  0  .  C18H850     +       CaS04     = 


Similarly  Gladding's  test  (p.  501)  for  rosin  acids  in  soap  depends 
on  the  precipitation  of  silver  stearate,  oleate,  &c.,  insoluble  in 
ether  containing  a  little  alcohol  when  silver  nitrate  acts  on  an 
alcoholic  solution  of  mixed  alkali  salts  ;  whereas  silver  resinate 
is  soluble  in  that  medium. 

Alkali  soaps  often  possess  in  a  high  degree  the  peculiar 
property  of  gelatin  and  other  colloid  bodies  —  viz.,  that  whilst  on 
heating  with  hot  water  they  apparently  dissolve  to  an  ordinary 
solution,  on  cooling  this  does  not  allow  crystals  of  material  to 
form  through  diminished  solubility  on  account  of  lowered  tem- 
perature, but  instead  sets  to  a  more  or  less  firm  jelly.  This 
property  of  "jellifying"  is  often  used  as  a  practical  test  of  the 
value  of  soap  for  certain  purposes  ;  a  known  weight  of  soap  is 
dissolved  in  water  (conveniently  1J  ounce  to  a  pint  =  20  fluid 
ounces,  or  62  -5  grammes  per  litre)  and  the  solution  allowed  to 
cool  ;  the  rate  at  which  the  fluid  gelatinises,  and  the  texture  of 
the  resulting  jelly  are  noted.  Preferably  the  soap  is  dissolved 
in  about  half  the  total  quantity  of  water,  boiling,  and  when  all 
is  in  solution  the  rest  of  the  water  is  added  cold. 

Although  alkali  soaps  are  usually  freely  soluble  in  water, 
especially  when  hot,  yet  the  presence  of  certain  other  substances 
in  solution  prevents  their  dissolving,  whilst  the  addition  of  these 
substances  to  aqueous  soap  solution  causes  the  precipitation  of 
more  or  less  of  the  dissolved  soap  ;  thus  the  process  of  "  salting 
out"  half  made  soap  in  the  open  pan  boiling  process  (p.  469) 
depends  on  the  less  degree  of  solubility  of  soap  in  brine  than 
in  pure  water.  Similarly,  when  curd  soap  is  boiled  down  on 


486  OILS,    FATS,    WAXES,    ETC. 

an  alkaline  ley,  the  soap  is  rendered  less  and  less  soluble  in 
the  watery  liquor  as  the  concentration  proceeds,  and  at  the  end 
of  the  operation  is  wholly  insoluble  therein,  even  if  partially 
soluble  at  first  when  the  ley  was  weaker. 

The  proportion  of  salt  relatively  to  water  required  to  render 
a  given  soap  insoluble,  obviously  varies  with  the  nature  of  the 
fatty  acids  present ;  thus  whilst  sodium  stearate  and  palmitate 
are  precipitated  from  solution  by  comparatively  small  amounts 
of  salt,  cokernut  and  palmnut  oil  soaps  are  sufficiently  soluble 
to  remain  dissolved  in  seawater,  which  usually  contains  3  to 
4  per  cent,  of  dissolved  solid  matters,  mostly  sodium  chloride. 
In  hot  brine  the  solubility  of  soap  is  usually  greater  than  in 
cold  :  thus  in  the  course  of  a  variety  of  experiments  on  the 
solubility  of  soaps  in  saline  solutions  Whitelaw  found  *  that 
tallow  soap  was  completely  soluble  to  a  clear  fluid  in  a  boiling 
solution  containing  not  more  than  3'0  per  cent,  of  NaCl,  the 
whole  setting  to  a  firm  jelly  on  cooling  ;  whilst  palmnut  oil 
soap  dissolved  clear  in  a  boiling  solution  containing  not  more 
than  13*0  of  NaCl,  a  large  portion  of  the  soap  being  thrown  out 
of  solution  on  cooling. 

The  curd  thrown  out  of  solution  by  salting  retains  an  amount  of 
associated  water  incapable  of  expression  mechanically  by  moderate 
pressure  in  a  dry  cloth,  and  hence  not  in  quite  the  same  condition 
as  ordinary  mechanically  entangled  fluid  ;  the  amount  of  this 
water  varies  inversely  with  the  concentration  of  the  saline  solu- 
tion ;  thus  the  longer  a  curd  soap  is  boiled  down  on  the  ley  so 
as  to  concentrate  this,  the  less  is  the  proportion  of  moisture 
retained  by  the  soap  after  separation  from  the  ley  and  framing 
so  as  to  solidify.  In  similar  fashion,  Whitelaw  found  that  an 
olive  oil  soap  retained  the  following  amounts  of  water  after  half 
an  hour's  boiling  with  different  brine  solutions  : — 

Salt  in  Brine.  Water  in  Curd. 

8  per  cent.  31  '6  per  cent. 

17         „  25-7 

27  (saturated).  |  19'1         „ 

Hydrolysis  of  Soap  Solutions. — When  soaps  are  dissolved 
in  absolute  alcohol,  or  in  spirit  containing  but  little  admixture 
of  water,  no  visible  decomposition  ensues ;  a  neutral  soap 
gives  a  solution  which  has  no  action  on  suitable  indicators 
— e.g.,  phenolphthalein.  If,  however,  water  be  substituted  for 
spirit,  the  soap  is  more  or  less  broken  up  into  caustic  soda  and 
an  acid  soap — e.g.,  in  the  case  of  stearate — 

Sodium  Stearate.  Water.  Caustic  Soda,  Sodium  Acid  Stearate. 

2Na  .  0  .  C18H350     +     H20  NaOH     +      {  H*  !  O  !  C^O 

A  pretty  way  of  illustrating  this  action  is  to  boil  a  piece  of  dried 
*  Journ.  Soc.  Chem.  Ind.,  1886,  p.  GO. 


HYDROLYSIS    OF    SOAP   SOLUTIONS. 


487 


soap  with  alcohol  to  which  a  little  phenolphthalein  has  been 
added,  and  filter  the  solution  into  a  tall  jar  or  large  test  tube ; 
the  solution  should  be  strong  enough  to  set  to  a  firm  jelly  on 
standing.  When  set,  a  little  distilled  water  is  poured  on  the 
top  of  the  jelly ;  this  hydrolyses  the  soap  in  the  top  layer  so  as 
to  turn  it  pink  by  the  reaction  on  the  phenolphthalein  of  the 
liberated  alkali.  On  standing,  the  water  gradually  dialyses 
downward  through  the  colloid  soap  mass,  and  the  pink  colour 
descends  with  it. 

By  adding  salt  to  an  aqueous  solution  of  soap  so  as  to  salt  out 
the  curd  completely,  filtering  off,  and  examining  the  filtrate 
alkalimetrically,  the  amount  of  alkali  set  free  under  given  condi- 
tions can  be  determined  ;  or  the  same  result  can  be  got  at  (with 
more  trouble)  by  collecting  the  salted  out  curd,  washing  with 
brine  over  the  vacuum  filter,  dissolving  the  curd  in  absolute 
alcohol,  and  titrating  the  acidity  with  phenolphthalein  as  indi- 
cator. A  long  series  of  observations  thus  made  led  to  the 
following  results  : — * 


Hydrolysis  brought  about  by  x  Molecules 

Mean 

of  Water. 

Fatty  Acids. 

Molecular 

Weight. 

a;  =150 

33  =  250 

x  =  500 

03  =  1000 

x  =  2000 

Pure  stearic  acid, 

284 

07 

i-o 

1-7 

2-6 

3-55 

Nearly  pure  palmitic  acid, 

250 

1-45 

1-9 

2-6 

3-15 

3-75 

Crude  lauric  acid  (cokernut 

oil),        .... 

195 

3-75 

4-5 

5-4 

6-45 

7-1 

Pure  oleic  acid, 

2S2 

1-85 

2-6 

3-8 

5-2 

6-65 

Crude  ricinoleic  acid, 

294 

1-55 

2-2 

3-0 

3-8 

4-5 

Chiefly    stearic,    palmitic, 

and  oleic  acids  (palm  oil 

tallow  soap), 

271 

1-1 

1-55 

2-6 

4-1 

5-3 

Chiefly   tallow    and    rosin 

* 

(primrose), 

280 

1-5 

2-2 

3-1 

4-2 

5-3 

Cotton  seed, 

250 

2-25 

3-0 

5-0 

7-5 

9-5 

Fig.  143  represents  these  results  in  the  form  of  curves,  from 
which  it  would  seem  to  result  inter  alia  that  amongst  homologous 
soaps  (stearic  acid,  palmitic  acid,  cokernut  oil  acids)  the  higher 
the  molecular  weight  the  less  rapid  the  hydrolysis. 

If  extra  alkali  be  added  to  the  soap  solution,  the  hydrolytic 
effect  is  proportionately  weakened,  as  suggested  by  the  character 
of  these  curves,  concave  downwards ;  thus  the  following  figures 
were  obtained  with  some  of  these  same  soaps  : — 

*  Alder  Wright  and  Thompson,  Journ.  Soc.  Chem.  Ind.,  1885,  p.  625; 
Alder  Wright,  "Cantor  Lectures,"  Society  of  Arts  (Journal  Soc.  Arts, 
xxxiii.,  1885,  p.  1124). 


488 


OILS,    FATS,    WAXKS,    ETC. 


Nature  of  Fatty  Acids  Used. 

Extra  Na2O 
added  to 
Solution,  per  100 

Soap. 

Hydrolysis  brought  about  by 
x  Molecules  of  Water. 

x=   50 

a=  250 

x  =  2000 

Crude  lauric  acid  (cokernut), 
Cotton  seed  oil  soap, 
Stearic  and  oleic  (tallow), 
Tallow  rosin  (primrose),    . 

11-0 
15-0 
20-0 
150 

1-1 

nil. 
nil. 

nil. 

1-6 
nil. 
nil. 

o-i 

2-0 
6-5 
nil. 
1-3 

The  property  of  becoming  hydrolysed  by  water  has  a  great 
deal  to  do  with  the  cleansing  and  detergent  action  of  soap  ;  the 


Values  of  X. 
Fig.  143. 

minute  amount  of  alkali  set  free  helps  to  emulsify  greasy  matters, 
and  thus  greatly  facilitates  their  removal  by  washing  out  under 
friction. 

Heaction  of  Soap  Solution  or  of  Fused  Soap  on  In- 
organic and  other  Salts. — When  a  solution  of  sodium  chloride 
is  added  to  one  of  a  soda  soap,  or  one  of  potassium  carbonate  to 
a  potash  soap,  there  being  but  one  base  present,  obviously,  no 
tendency  can  exist  towards  double  decomposition  and  exchange 
of  bases ;  but  it  is  otherwise  if  sodium  chloride  be  added  to  a 
potash  soap,  or  potassium  chloride  to  a  soda  soap ;  or  if  potassium 
carbonate  be  added  to  a  soda  soap  or  sodium  carbonate  to  a 
potash  soap.  In  certain  of  these  cases  it  is  well  known  that 
double  decomposition  ensues ;  thus,  if  a  potash  soap  be  made  by 


PEARLASHING.  489 

boiling  fatty  matter  and  wood  ash  ley  together,  and  sodium 
chloride  be  then  used  to  salt  it  out  of  solution,  the  resulting  curd 
is  largely  composed  of  soda  soap  formed  by  the  reaction  (in  the 
case  of  stearate). 

Sodium  Chloride.     Potassium  Stearate.  Sodium  Stearate.      Potassium  .Chloride. 

NaCl     +     K.O.C18H350     =     Na .  0  .  Ci8H350     +     KC1 

In  former  days  this  reaction  was  utilised  to  prepare  hard  soaps  in 
places  where  wood  ashes  only  were  obtainable  as  alkali  (p.  473). 
Similarly,  it  has  long  been  a  practice  to  improve  the  softness 
and  texture  of  soda  soaps  intended  for  toilet  soapmaking  by 
remelting  and  "  pearlashing " — i.e.,  adding  to  the  melted  soap 
potassium  carbonate  dissolved  in  a  little  water ;  the  rationale  of 
which  has  been  shown  to  be  *  that  double  decomposition  takes 
place  with  formation  •  of  potash  soap  and  sodium  carbonate, 
thus — 

Sodium  Stearate.       Potassium  Carbonate.     Potassium  Stearate.      Sodium  Carbonate. 
2Na.O.C18H350     +     K2C03  2K.O.C18H35O     +     Na2C03 

The  presence  of  the  potash  soap  makes  the  resulting  mass  less 
liable  to  crack  during  stamping,  and  also  gives  it  better  lathering 
qualities. 

In  these  and  all  similar  cases  the  general  principle  involved 
seems  to  be  this.  Potassium  and  sodium  are  so  related  that  when 
both  alkalies  are  simultaneously  in  presence  of  two  acids,  one 
weaker  than  the  other,  the  potash  tends  to  unite  with  the 
stronger  acid  and  the  soda  with  the  other.  Thus  when  stearic 
and  hydrochloric  acids  are  in  question,  the  prevailing  tendency  is 
to  form  potassium  chloride  and  sodium  stearate,  because  hydro- 
chloric acid  is  the  stronger  acid  of  the  two;  whilst  when  stearic 
and  carbonic  acids  are  the  two  acids,  the  chief  tendency  is  to 
form  potassium  stearate  and  sodium  carbonate,  because  stearic 
acid  is  a  stronger  acid  than  carbonic  acid.  As  in  most  analogous 
cases,  however,  the  question  of  relative  masses  is  also  concerned 
in  the  result ;  if  these  be  suitably  chosen  the  actions  may  to 
some  extent  be  reversed — e.g.,  if  a  large  mass  of  potassium 
chloride  act  on  a  relatively  small  quantity  of  sodium  stearate,  a. 
notable  amount  of  soft  potassium  stearate  is  formed  with  a 
corresponding  quantity  of  sodium  chloride,  in  opposition  to  the 
above  described  actions  occurring  when  the  masses  of  potassium 
and  sodium  salts  are  not  widely  different.  Similarly,  if  a 
relatively  large  amount  of  sodium  carbonate  acts  on  a  small 
quantity  of  fused  potash  soap,  a  measurable  amount  of  soda 
soap  and  a  corresponding  quantity  of  potassium  carbonate  are 
produced,  notwithstanding  the  usual  tendency  to  the  opposite 

*  Alder  Wright  and  Thompson,  Journ.  Soc.  Chem.  Ind.,  1885,  p.  625. 


490 


OILS,    FATS,    WAXES,    ETC. 


change.      Thus    the  following  figures  were  obtained  by  Alder 
Wright  and  Thompson  (loc.  cit.  supra) : — 


(<j)  Soda  Soaps  fused  with 
KoCO3.    Percentage  of  total 
Fatty  Acids  present 

(b)  Potash  Soaps  fused  with 
Na2CO3.    Percentage  of 
totat  Fatty  Acids  present 

Fatty  Acids  Employed. 

Equivalent  to 
the  K2C03 

Actually  con- 
verted into 

Equivalent  to 
the  Na2(J03 

Actually  con- 
verted into 

added. 

Potash  Soup. 

added. 

Soda  Soap. 

Stearic  and  oleic  (tallow), 

10-4 

8-0 

53 

45-7 

34-4        ! 

... 

33                                              55 

100-0 

97-95 

100-0 

4-3 

104-2 

99-0 

1000-0 

15-0 

Stearic,     palmitic,      and 

oleic  (palm  oil  and  tal- 

57-2 

52-1 

low),    .... 

5  5                                               3» 

108-0 

90-8 

177-0 

9-5 

Crude  Jauric  acid  (coker-  \ 
nut  oil),        .         .         .  J 

52-8 

464 

55                                              55 

114-8 

87-9 

197-0 

6-2 

Crude  ricinoleic  acid  (cas- 

50-0 

48-4 

tor  oil), 

53                                              33 

100-0 

93-8 

2050 

8-2 

Obviously  the  proportion  of  potassium  carbonate  converted 
into  potash  soap  in  the  series  (a)  is  uniformly  much  larger  than 
the  fraction  of  sodium  carbonate  converted  into  sodium  soap  in 
series  (b) — i.e.,  not  far  from  the  maximum  possible  in  the  first  case, 
and  only  a  few  per  cents,  in  the  second ;  showing  the  much 
stronger  tendency  towards  the  first  change  than  towards  its 
converse. 

In  similar  fashion  the  following  figures  were  obtained  on 
salting  out  potash  soaps  with  sodium  chloride,  and  soda  soaps 
with  potassium  chloride ;  in  series  (a)  m  molecules  of  water  were 
used  to  dissolve  1  of  potash  soap,  and  n  molecules  of  sodium 
chloride  added ;  in  series  (b)  m  molecules  of  water  were  added  for 
1  of  soda  soap,  and  n  molecules  of  potassium  chloride  added  : — 


Fatty  Acid  Used. 

m. 

n. 

(a)  Potash  Soaps  salted 
out  with  NaCl.    Per- 
centage of  Fatty  Acid 
in  Curd. 

(b)  Soda  Soaps  salted 
out  with  KC1.    Per- 
centage of  Fatty  Acid 
in  Curd. 

As  Potash 
Soap. 

As  Soda 
Soap. 

As  Potash 
Soap. 

As  Soda 
Soap. 

Stearic    and    oleic    acids 
(tallow), 
Stearic    and    oleic    acids 
(tallow), 
Stearic,  palmitic,  and  oleic 
acids  (palm  oil  &  tallow)  , 
Crude  lauric  acid  (coker- 
nut  oil), 

100 
200 
200 
200 

5 
20 
20 
20 

10-5 
5-1 

3-8 
5-4 

89-5 
94-9 
96-2 
94-6 

79-1 

82-1 
95-8 
74-8 

20-9 
17-9 
4-2 
25-2 

SALTING    OUT. 


491 


Here  the  disproportion  between  the  results  in  the  (a]  series  and 
those  in  the  (b)  series  is  much  less  than  in  the  case  of  carbonates, 
although  it  is  still  obvious  that  on  the  whole  there  is  a  greater 
tendency  for  sodium  chloride  to  form  a  soda  soap  by  acting  on  a 
potash  soap,  than  for  the  converse  reaction  to  occur. 

The  same  result  follows  if  a  mixture  of  equivalent  quantities 
of  potash  and  soda  soaps  (obtained  by  halving  the  fatty  acid,  and 
neutralising  one  half  with  one  alkali,  and  the  other  with  the 
other)  be  dissolved  in  water  and  salted  out  with  a  mixture  of 
equivalent  quantities  of  potassium  and  sodium  chlorides ;  a  much 
larger  proportion  of  soda  soap  is  thus  separated  than  is  equiva- 
lent to  the  potash  soap  simultaneously  thrown  out  of  solution, 
the  precise  proportion  varying  with  the  nature  of  the  fatty  acids. 
Thus  the  following  figures  were  obtained,  indicating  from  1'6  to 
5  '7  molecules  of  soda  soap  to  1  of  potash  soap:  — 


- 

Percentage  of  Fatty  Acid  contained. 

Molecular  Ratio  of 

Soda  Soap  to 

As  Potash  Soap. 

As  Soda  Soap. 

Potash  soap. 

Pure  oleic  acid,  . 

38-0 

62-0 

1-63  to  1 

Crude  ricinoleic  acid  (from 

castor  oil), 

17-8 

82-2 

4-6    to  1 

Stearic,  oleic,  and  rosin  acids 

mixed  (primrose  soap),    . 

17-2 

82-8 

4-8    to  1 

Crude    lauric    acid    (  from 

cokernut  oil  soap),  . 

15-1 

85-9 

5-7    to  1 

It  is  remarkable  that  when  only  one  acid  is  present,  or  a 
mixture  of  organic  acids  not  greatly  differing  in  strength,  the 
proportion  of  soda  and  potash  soaps  formed  by  acting  on  a  mixture 
of  the  two  bases  is  sensibly  the  same  as  the  proportion  of  the 
bases ;  thus  with  equal  molecular  quantities  of  potash  and  soda, 
and  amounts  of  acid  exactly  equivalent  to  either  of  the  alkalies 
separately,  or  to  one-half  of  the  two  jointly,  the  following  figures 
were  obtained : — 


Fatty  Acids  Employed. 

Percentage  of  Total  Fatty  Acid 
converted  into 

Soda  Soap. 

Potash  Soap. 

51-2 
50-8 
51-5 

48-2 
49-7 

48-8 
49-2 
48-5 

51-8 
50-3 

,,     oleic  acid,      ..... 
Crude  stearic  and  oleic  acids  (tallow),    . 
,,       stearic,  palmitic,  and  oleic  acids  ) 
(palm  oil  and  tallow),        .         .  f 
,,       lauric  acid  (cokernut  oil),    . 

Mean, 

50-3 

49-7 

492  OILS,    FATS,    WAXES,    ETC. 

In  similar  fashion,  if  a  soda  soap  be  melted  and  well  inter- 
mixed with  just  as  much  caustic  potash  as  is  chemically 
equivalent  to  the  soda  present,  or  if  a  potash  soap  be  similarly 
treated  with  the  equivalent  amount  of  caustic  soda,  the  result  in 
either  case  is  the  formation  of  a  mixture  of  potash  and  soda  soaps 
in  practically  equivalent  quantities. 


ANALYSIS  OF  SOAPS. 

The  general  composition  and  character  of  soaps  of  different 
kinds  being  subject  to  considerable  variation,  the  analytical 
determinations  most  useful  in  certain  cases  are  not  always  those 
most  valuable  in  other  instances.  Thus  in  the  case  of  a  fulling  or 
woolscouring  soap,  freedom  from  excess  of  alkali  or  from  alkaline 
salts  (silicate,  £c.)  that  might  act  injuriously  on  the  wool  fibre  is 
the  most  important  point,  together  with  the  proper  nature  of  the 
fatty  matters  employed  ;  whilst  in  the  case  of  a  laundry  soap, 
freedom  from  excess  of  alkali  is  not  at  all  an  important  condition, 
the  presence  of  certain  kinds  of  alkaline  material  (more  especially 
alkaline  carbonates)  being  generally  beneficial  rather  than  other- 
wise, cceteris  paribus.  In  all  cases,  however,  a  highly  important 
consideration  is  the  proportion  of  actual  soap  present— i.e.,  the 
proportion  of  the  alkaline  salts  of  fatty  and  resinous  acids,  apart 
from  other  saline  matters,  uncombined  alkalies,  unsaponified 
glycerides,  water,  glycerol,  and  substances  added  to  give  weight, 
or  to  increase  the  stiffness,  or  the  detergent  action,  or  for  other 
reasons.  An  examination  of  the  fatty  acids  set  free  on  decom- 
position with  a  mineral  acid  is  often  useful,  as  giving  information 
as  to  the  nature  and  quality  of  the  fatty  matters  originally 
employed ;  the  first  results  being  corrected,  when  necessary,  by 
determining  the  amount  of  unsaponified  fat  present,  and  also  the 
amount  and  general  nature  of  unsaponifiable  constituents,  such 
as  cholesterol,  hydrocarbons,  &c.  Moreover,  with  certain  kinds 
of  medicated  and  disinfectant  soaps  the  amount  of  active 
ingredient  incorporated  therein  requires  determination. 

When  the  amount  of  total  alkaline  matter  present  (soda, 
or  potash,  or  both)  is  known,  expressed  as  anhydrous  oxide 
(Na.,O,  or  K2O)  and  also  that  portion  which  is  "  free  " — i.e.,  not 
combined  with  fatty  and  resinous  acids,  the  difference  obviously 
represents  the  combined  alkali  contained  as  actual  soap  :  i.e.,  if 
the  percentage  of  "total  alkali"  (expressed  as  Na20)  be  a,  and 
that  of  "free  alkali  =  b,  a  -  b  is  the  percentage  of  "combined 
alkali."  Similarly  if  c  be  the  percentage  of  crude  fatty  acids,  &c., 
obtained  on  decomposition  with  a  mineral  acid,  whilst  d  is  the 
percentage  of  unsaponified  grease  and  unsaponifiable  matters 
present  therein  admixed  with  the  pure  fatty  acids,  c  -  d  is  the 
percentage  of  fatty  acids  contained  combined  as  soap.  The 


ANALYSIS    OF    SOAPS.  493 

weight  of  actual  soap  present  then  is  a  -  b  +  (c  -  d)  -  n  per  cent., 
where  n  is  the  amount  to  be  subtracted  in  order  to  calculate 
fatty  acids  into  fatty  anhydrides  (the  soap  being  viewed  for 
present  purposes  as  made  up  of  compounds  of  metallic  oxides 
and  the  anhydrides  of  acids,  such  as  Na20,  (C]8H35O).2O  for 
sodium  stearate,  and  so  on).  Obviously,  if  the  alkali  be  expressed 

9 

as  Na.,O,    n  =  ^  (a  -  b) ;    whilst  if  it  be  expressed    as   K0O, 
ol 

Q 

n  =          (a-b);  so  that  in  the  first  case  the  percentage  of  actual 

soap  is — 

•  -»  +  (c-d)-  -Ji(a-b)  =  ~(o-6)  +  (c-d) 

and  in  the  second  case — 

Q  38  •! 

a-b  +  (c-d)-~(a-b)  =  ^-(a-b)  +  (c-d) 

For  instance,  suppose  that   a   soda  soap  gave  the  following 
results  on  analysis  — 

Crude  mixture  of  fatty  acids,  &c.,       =       c        =       67 '05  per  cent. 
Unsaponifiable  matters,  &c.,         .       =      rf       -        1*80        „ 

Fatty  acids  present  in  soap,    .       =    c-d    —      65 '24        „ 

Total  alkali  (expressed  as  Na20),        =       a       =        8' 55 
Free  alkali  ,,  =       b        =        0'85        ,, 

Combined  alkali  present  in  soap,  =    a-b    =        7 '70        ,, 

Hence—  n  =  ~ -  x  7  "70  =  2  -23 

ol 

Whence  the  fatty  anhydrides  are     65'25       -       2'23      =      03 -02 
And  the  actual  soap  present      =       63 '02       +       7 '70       =       70 '72 

The  analysis  would  then  be  stated  thus — 

Fatty  anhydrides,       .         .     63  '02  per  cent.  "I  Jointly  =  7072  per  cent,  of 

Combined  alkali  (Na20),     .       7'70        ,,          J      actual  soap. 

Unsaponifiable  matters,  &c.,     1*80        ,, 

Water,  free  alkali,  saline  )  /Containing  free  alkali  equi- 

matters,  &c.  (by  differ-  >  27  '48  ,,  I  valent  to  °'85  Per  cent- 
ence)'  •  •  •  )  )  Na20,  or  ~|  =  about  ?  of 


\ 


100-00  V     the  combined  alkali. 


In  order,  therefore,  to  determine  the  percentage  of  actual  soap 
present,  the  four  quantities  a,  b,  c,  and  d  must  be  determined  ; 
during  the  course  of  which  analysis,  the  separate  percentages  of 
potash  and  soda  may  conveniently  be  also  determined  (when  the 
two  alkalies  are  simultaneously  present) ;  moreover,  whilst  c  and  d 


494  OILS,    FATS,    WAXES,    ETC. 

are  being  separated  from  one  another,  the  respective  amounts  of 
unsaponified  glycerides  and  of  unsaponifiable  matters  present  in  d 
may  be  conveniently  determined,  and  further  examinations  made 
as  to  the  characters  of  the  separated  and  purified  fatty  acids,  c  —  d, 
and  of  the  unsaponifiable  matters ;  in  particular  the  proportion  of 
rosin  acids  in  the  former  may  be  determined,  as  also  the  melting 
point,  &c.,  so  as  to  obtain  information  as  to  the  probable  nature  of 
the  fatty  matters  used.  This  last  point,  however,  is  one  where 
analytical  data,  as  such,  often  fail  to  give  satisfactory  results — i.e., 
the  inspection  of  the  mixed  fatty  acids  and  the  valuation  of  their 
fusing  points,  &c.,  often  leads  to  nothing  definite ;  in  some  cases, 
however,  the  application  of  other  tests  (qualitative  or  quantita- 
tive) leads  to  useful  results — e.g.,  the  elaidin  test,  &c. 

The  average  molecular  weight,  E,  of  the  fatty  acids  contained 
in  the  soap  is  frequently  a  datum  of  considerable  value  ;  this  is 
readily  deduced  when  a,  b,  c,  and  d  are  known,  as  shown  on 
p.  172,  being  given  by  the  equation — 

E  = x  31,  when  the  alkali  is  expressed  as  Na<>0 

a-  6 

B=~-|-x47'l  „  „  „  K20 

Thus,  in  the  above  example,  the  value  of  E  is — 

^^>  x  31  =263. 

7'7u 

"When  required,  the  proportion  of  water  present  in  the  soap  may 
be  directly  determined,  as  also  any  other  constituents  present, 
such,  for  example,  as  admixed  weighting  substances  of  mineral 
or  organic  nature  (china  clay,  steatite,  starch,  sand,  bran,  <fec.); 
saline  matters  (sodium  chloride,  sulphate,  <fec.) ;  silica  (from 
sodium  silicate) ;  glycerol  •  sugar  ;  and  so  on. 

In  order  to  carry  out  a  complete  detailed  analysis  the  follow- 
ing methods  of  procedure  have  been  found  convenient  by  the 
author,*  the  exact  selection  to  be  made  varying  with  circum- 
stances. 

Water. — A  convenient  weight  of  an  average  sample  of  the 
soap  cut  up  into  thin  shavings  is  dried,  first  at  a  temperature 
somewhat  below  100°  so  as  to  avoid  fusion,  finally  at  110°-120°. 
The  loss  of  weight  may  be  taken  as  water,  especially  when  other 
volatile  substances  (carbolic  acid,  essential  oils,  <kc.)  are  absent 

*  Various  more  or  less  similar  methods  and  processes  have  been  pre- 
viously put  forward  by  other  chemists — e.g.,  C.  Hope,  Chemical  News, 
xliii.  (1881),  p.  219;  Filsinger,  Chemiker  Zeituny,  April,  1884;  Allen,  Com- 
mercial Organic  Analysis,  Second  Edition,  vol.  ii.,  p.  251;  Leeds,  Chemical 
News,  xlviii.  (1885),  p.  166;  Alder  Wright  &  Thompson,  Analyst  (1886), 
p.  44 ;  &c. 


WATER,    UNSAPONIFIED    FAT,    ETC.  495 

or  only  present  in  small  quantities.  For  many  purposes  this 
direct  determination  is  one  of  the  most  important  valuations, 
especially  in  conjunction  with  an  estimation  of  free  alkali  (e.g., 
in  the  case  of  soft  soap).  In  other  cases  the  direct  determination 
is  quite  unnecessary,  more  particularly  when  the  amount  of 
actual  soap  present  is  determined,  wTater  and  saline  matters  being 
conveniently  taken  by  difference.  Instead  of  reducing  the  soap 
to  thin  slices  and  drying  without  fusion,  the  amount  of  water  may 
be  arrived  at  by  heating  5  or  10  grammes  in  a  large  porcelain 
crucible  set  in  a  sand  bath,  and  stirring  with  a  bit  of  glass  rod 
(weighed  with  the  crucible)  until  no  more  dew  is  deposited  on 
a  piece  of  glass  placed  over  the  crucible  (the  lamp  being  removed). 
"When  this  stage  is  reached  the  water  is  practically  all  expelled, 
and  a  nearly  constant  weight  attained.  Care  must  be  taken  not 
to  overheat  and  burn  the  soap ;  the  glass  rod  should  have  a 
rough  jagged  end  to  facilitate  the  breaking  up  of  clots.* 

J.  A.  Wilson  recommends  t  weighing  out  about  2 -5  grammes 
of  soap  in  a  dish  and  dissolving  in  about  5  c.c.  of  absolute  alcohol 
by  means  of  heat ;  about  10  grammes  of  ignited  sand  are  then 
added  and  the  whole  evaporated  to  dryness ;  the  residue  is  again 
treated  with  5  c.c.  of  absolute  alcohol  and  evaporated  and  finally 
dried  at  100°  to  105°  in  an  airbath.  The  addition  of  the  sand 
facilitates  the  expulsion  of  water  along  with  the  alcohol,  and 
renders  it  more  easy  to  treat  the  dried  soap  in  a  Soxhlet 
apparatus  for  dissolving  out  unsaponified  fat,  &c. 

Un  saponified.  Fat,  Hydrocarbons,  Spermaceti,  Wax,  &c.— 
5  (or  preferably  10)  grammes  of  soap  are  dried,  first  at  100°  or 
belowr,  and  finally  at  120° ;  or  in  a  crucible,  or  with  alcohol  and 
sand  as  above :  the  residue  is  exhausted  in  a  Soxhlet  tube  (p.  238) 
with  light  petroleum  spirit ;  or  a  little  spirit  is  poured  on,  allowed 
to  digest,  poured  off  (if  necessary  through  a  filter),  and  so  on  until 
all  fat,  &c.,  is  dissolved  out.  Ether  may  also  be  used,  but  is  more 
apt  to  dissolve  out  soap.  The  residue  left  on  evaporation  of  the 
solvent  may  be  examined  as  to  its  physical  properties,  and  the 
saponifiable  portion  thereof  determined  by  heating  with  excess, 
of  standard  alcoholic  potash,  precisely  as  in  determining  the  "total 
acid  number"  of  an  oil  or  fat  (p.  157,  et  seq.)  When  saponifica- 
tion  is  complete  (which  may  in  some  cases  require  an  hour's 
boiling  with  a  reflex  condenser,  or  more)  the  unneutralised 
alkali  is  back-titrated  :  the  exactly  neutral  fluid  is  then  evapor- 
ated and  the  residue  again  treated  with  light  petroleum  spirit 
so  as  to  dissolve  out  hydrocarbons,  cholesterol  or  other  alco- 
holiform  saponification  products,  &c.,  obtained  by  evaporating 
the  extract  ;  whilst  the  undissolved  portion  on  acidulation  and 
shaking  with  ether  enables  the  fatty  acids,  &c.,  produced  by  the 
saponification  to  be  isolated  for  examination.  In  cases  where 

*  Watson  Smith,  Journ.  Soc.  Dyers  and  Colour  ist*,  vol.  i.,  p.  31. 
t  Chemical  News,  October  21,  1892,  p.  200. 


496  OILS,    FATS,    WAXES,    ETC. 

a  full  examination  of  the  unsaponified  fat,  &c.,  is  requisite  it  is 
preferable  to  employ  a  larger  quantity  (50  grammes  or  even 
100)  of  soap,  and  not  to  combine  this  determination  with  that  of 
water,  &c.,  lost  by  drying.  As  a  rule  little  but  unsaponified 
glycerides  are  thus  extracted;  but  "  oleine  "  soaps  often  contain 
a  small  percentage  of  hydrocarbons  contained  in  the  oleine 
(distilled,  p.  278),  whilst  if  woolgrease  have  been  used  to  adul- 
terate tallow,  notable  amounts  of  cholesterol,  ttc.,  may  be  present. 
Spermaceti,  vaseline,  &c.,*  may  be  present  in  special  kinds  of 
toilet  soap ;  whilst  certain  laundry  soaps  are  purposely  inter- 
mixed with  paraffin  oil  and  similar  hydrocarbons. 

The  unsaponified  fat,  ttc.,  may  also  be  isolated  by  dissolving 
the  soap  (which  need  not  be  dried)  in  hot  alcohol  and  somewhat 
diluting  with  water  ;  before  complete  cooling  a  little  ether  is 
dropped  in  (care  being  taken  that  no  light  is  near  to  inflame 
ether  vapour),  which  will  generally  prevent  the  mass  gelatin- 
ising. More  ether  is  added  and  the  whole  well  agitated,  and 
if  separation  does  not  occur,  more  water  is  added,  the  ethereal 
solution  being  finally  drawn  off  by  means  of  a  separating  funnel 
or  Chatta way's  tube  (p.  120).  The  ethereal  extract  thus  obtained 
usually  contains  soap,  so  that  it  should  be  evaporated  and  the 
residue  dissolved  in  petroleum  spirit  and  filtered.  Some  little 
.amount  of  "dodging"  is  sometimes  requisite  to  get  the  alcohol, 
•ether,  and  water  in  the  right  proportions  to  bring  about  a  proper 
separation  into  two  fluids,  one  a  watery  alcoholic  soap  solution, 
the  other  an  ethereal  solution  of  fat,  &c. 

Fatty  Anhydrides  and  Total  Alkali. — The  residue  de- 
prived of  fat,  &c.,  by  petroleum  spirit  left  in  the  Soxhlet  tube 
as  above,  is  dissolved  in  water  f  and  decomposed  by  boiling  with  a 
slight  excess  of  standard  acid.  On  standing  and  cooling  the  fatty 
acids  separate  as  a  cake,  which  is  washed,  dried,  and  weighed,  J 

*  When  wax  is  present,  toluene  dissolves  it  out  in  the  Soxhlet  tube 
better  than  petroleum  spirit  (Schuaible). 

tlf  mineral  matters,  &c.,  insoluble  in  alcohol  are  present,  the  soap 
may  be  treated  (conveniently  still  in  the  Soxhlet  tube)  with  alcohol,  so  as 
to  dissolve  out  the  soap,  and  leave  the  insoluble  substances.  In  this  case 
drying  without  addition  of  sand,  &c. ,  is  preferable.  The  alcoholic  extract 
may  be  evaporated  to  dryness  and  the  residue  weighed,  so  as  directly  to 
determine  the  "actual  soap  "  present ;  or  it  may  be  diluted  with  hot  water 
and  treated  with  excess  of  standard  acid,  &c. 

£0r  the  hot  fluids  may  be  washed  into  a  separating  funnel,  the  watery 
part  run  off,  and  the  fluid  fatty  acids  washed  out  on  to  a  wet  filter  as  in 
determining  the  Hehner  number  of  an  oil,  &c.  (p.  166).  If  particles  of 
fatty  acid  adhere  to  the  vessels  either  in  this  mode  of  operating  or  with 
the  solid  cake,  they  should  be  washed  off  with  a  little  ether,  &c.,  into  a 
small  beaker  or  basin,  and  the  solvent  evaporated,  the  rest  of  the  fatty 
acids  being  subsequently  added,  and  the  whole  weighed  together  after 
drying.  When  the  soap  contains  any  considerable  amount  of  soluble  fatty 
acids  (e.g.,  when  made  from  mixtures  containing  cokernut  or  palm  kernel 
oil)  these  partly  remain  in  the  aqueous  liquor  from  which  they  may  be 
mostly  extracted  by  shaking  with  ether. 


FATTY    ANHYDRIDES   AND    TOTAL    ALKALI.  497 

and  then  subjected  to  such  further  tests  as  may  be  deemed 
necessary  (melting  point,  elaidin  test,  &c.),  more  especially  rosin 
acid  determination  (infra).  If  the  fatty  acids  are  very  soft,  or 
are  derived  from  coker  or  palm  kernel  oil,  a  known  weight  (5  or 
10  grammes)  of  beeswax  or  paraffin  wax  may  be  advantageously 
added  before  cooling  so  as  to  form  a  more  solid  cake,  and  to 
assist  in  dissolving  out  from  the  water  the  more  soluble  acids, 
due  correction  being  made  for  the  weight  of  added  substance  : 
this,  however,  obviously  prevents  any  physical  or  other  examina- 
tion of  the  fatty  acids  after  their  being  separated  from  the  soap. 
If  such  an  examination  is  not  requisite  it  often  saves  time  to 
weigh  up  a  separate  amount  of  average  soap  (10  grammes*)  and 
without  drying  or  treating  with  petroleum  spirit  to  dissolve  this 
in  water,  decompose  with  acid,  and  weigh  the  resulting  mixture 
of  fatty  acids,  unsaponified  fat,  &c.,  correcting  the  result  by 
means  of  a  separate  determination  of  the  latter  quantity.  The 
corrected  percentage  of  fatty  acids  is  calculated  to  fatty  anhy- 
drides as  above  described  (p.  493). 

"When  nitric  acid  is  used  as  the  standard  acid,  and  the  alkali 
employed  for  back-titration  f  is  free  from  chloride  and  sulphate, 
the  neutralised  fluid  may  be  divided  into  two  halves  for  the 
determination  of  sulphate  and  chloride  respectively ;  or,  if 
requisite,  a  portion  may  be  reserved  for  glycerol  determination 
(infra). 

From  the  amount  of  standard  acid  used,  less  that  titrated  in 
the  liquid  after  removal  of  fatty  acids,  the  total  quantity  of 
alkali  present  is  known,  including  that  present  as  soap,  that 
contained  as  hydroxide  or  carbonate,  and  that  present  as  other 
inorganic  salts  of  alkaline  reaction — e.g.,  silicate. 

*  Instead  of  using  10  grammes  of  soap,  a  smaller  quantity,  say  2  grammes, 
may  be  dissolved  in  water,  acidulated,  shaken  with  ether  in  a  well  closed 
vessel,  and  the  ethereal  solution  separated  and  evaporated  ;  this  method  is 
preferable  with  soaps  made  from  cokeriiut  and  palm  kernel  oils  on  account 
of  the  partial  solubility  of  the  fatty  acids  thence  derived  in  water.  In 
order  to  avoid  loss  of  volatile  acids  during  drying,  the  ethereal  solution 
may  be  exactly  neutralised  with  alcoholic  solution  of  pure  soda,  evaporated 
to  complete  dryness,  and  weighed.  By  subtracting  the  Na20  contained 
in  the  alcoholic  soda  from  the  weight  of  the  pure  soap  (together  with 
unsaponified  grease  and  unsaponinable  matters)  thus  obtained,  the  weight 
of  fatty  anhydrides  +  unsaponified  grease  and  imsaponifiable  matters  is 
known.  The  soda  thus  neutralised  is  the  "combined  alkali"  (vide  infra, 
"  fatty  acid  titration  test "  for  free  alkali). 

t  Cochineal  is  a  convenient  indicator  for  the  purpose.  If  any  soluble 
organic  acids  are  present  in  the  watery  fluid,  they  may  be  approximately 
estimated  by  first  titrating  with  methyl  orange  as  indicator,  the  colour 
change  occurring  when  all  the  mineral  acid  present  is  neutralised  ;  and 
then  g"ing  on  with  addition  of  phenolphthalein,  which  is  not  reddened  till 
the  organic  acids  are  neutralised.  The  additional  alkali  thus  consumed 
may  be  calculated  as  valeric  acid,  C5H1002,  in  the  case  of  soaps  containing 
whale  oils  ;  or  as  heptoic  acid,  C7H1402,  or  octoic  acid,  CsHje^^,  in  the  case 
of  cokernut  oil  soaps. 

32 


498  OILS,    FATS,    WAXES,    ETC. 

Free  Alkali. — The  term  "free  alkali"  is  generally  understood 
as  including  the  alkalinity  of  all  substances  present  in  soap  pos- 
sessing an  alkaline  reaction— i.e.,  the  sum  of  the  alkalinity  due 
to  hydroxide  (caustic  alkali),  carbonate,  and  other  salts  such  as 
silicate ;  so  that  the  difference  between  the  "  total  alkali "  and 
the  "free  alkali "  exactly  represents  the  alkali  combined  with 
fatty  and  resinous  acids  as  actual  soap. 

Excepting  with  freshly  made  soap,  especially  when  preserved 
in  large  sized  blocks,  but  little  caustic  alkali  is  ever  found  in 
commercial  soap,  because  the  absorption  of  carbon  dioxide  from 
the  air  is  tolerably  rapid ;  but  the  passage  of  that  gas  into  the 
interior  of  a  large  mass,  and  to  a  lesser  extent  into  the  centre  of 
an  ordinary  bar,  is  by  no  means  instantaneous,  so  that  the 
interior  portion  of  a  comparatively  freshly  made  curd  or  hydrated 
soap  (pp.  461,  470)  often  contains  a  notable  amount  of  hydroxide. 
In  order  to  distinguish  the  free  alkali  present  as  hydroxide  from 
that  contained  in  other  forms,  C.  PI  ope  *  dissolves  a  known 
weight  of  an  average  sample  in  strong  alcohol  and  filters ;  car- 
bonate, silicate,  &c.,  are  left  on  the  filter ;  'whilst  caustic  alkali 
(whether  potash  or  soda)  passes  through,  dissolved  in  the  alcohol 
along  with  the  neutral  soap.  The  operation  may  be  conveniently 
carried  out  thus,  constituting  the  "alcohol  test"  for  free  alkali. 
5  grammes  of  undried  average  sample  of  soap  are  dissolved  in 
hot  alcohol  (free  from  all  acidity  or  alkalinity,  and  as  strong  as 
possible)  and  the  solution  filtered  through  a  hot  water  funnel  : 
after  completely  washing  out  with  alcohol,  the  undissolved 
residue  is  treated  with  water  and  the  alkalinity  determined. 
As  a  general  rule,  the  alcoholic  filtrate  is  neutral,  but  sometimes 
it  is  faintly  acid  to  phenolphthalein ;  apparently  with  a  slightly 
moist  soap  mass,  absorption  of  carbonic  acid  from  the  air  tends 
to  develop  a  trace  of  "acid  soap"  (pp.  23,  486)  with  a  correspond- 
ing quantity  of  alkaline  carbonate;  as  this  latter  is  undissolved 
by  the  alcohol  it  does  not  react  on  the  acid  soap  during  solu- 
tion so  as  to  neutralise  it  again,  f  In  such  a  case  the  acidity 
("  negative  alkalinity  ")  of  the  alcoholic  solution  is  determined, 
and  the  amount  subtracted  from  the  positive  alkalinity  of  the 
residue.  Thus  5  grammes  of  soap  gave  an  alcoholic  solution 
where  the  acidity  represented  0'25  c.c.  of  seminormal  alkali; 
whilst  the  residue  neutralised  0'6  c.c.  of  seminormal  acid  :  hence 
the  "free  alkali"  is  reckoned  as  O6  -  O25  =  0-35  c.c.  of  semi- 
normal  acid  corresponding  with  0-0054  gramme  of  soda  (Na2O) 
or  0-108  per  cent. 

Sometimes,  on  the  other  hand,  the  alcoholic  filtrate  is  more  or 

*  Chemical  News,  xliii.  (1881),  p.  219. 

t  With  some  kinds  of  soap,  if  a  stream  of  pure  carbon  dioxide  be  passed 
through  a  hot  clear  filtered  alcoholic  solution  of  the  soap,  a  slight  visible 
precipitation  of  alkaline  carbonate  results,  together  with  the  formation  of  an 
equivalent  amount  of  "acid  soap." 


FREE    ALKALI.  ,499 

less  alkaline  (through  the  presence  of  hydroxide  in  the  soap) ; 
in  which  case  the  amount  of  alkali  present  in  the  nitrate  is 
determined  (using  phenolphthalein  as  indicator)  and  added  to 
that  found  in  the  residue,  this  method  of  operating  being 
"  Hope's  test "  in  its  original  form.  It  has  been  pointed  out  by 
J.  A.  Wilson  *  that  when  caustic  alkali  is  present  in  a  soap 
which  also  contains  unsaponified  glycerides,  the  alcoholic  alkaline 
solution  is  apt  to  act  on  these  glycerides,  diminishing  the  alka- 
linity by  saponifying  them,  and  so  causing  the  amount  of  free 
alkali  to  be  understated.  The  author  has  found  that  this 
source  of  error  is  readily  avoided  by  cutting  the  soap  to  be 
examined  into  very  thin  slices  or  shavings,  and  exposing  these 
loosely  piled  together  in  a  small  dish  or  beaker  to  the  action  of 
carbon  dioxide,  conveniently  by  placing  the  dish  in  a  wide 
mouthed  bottle  filled  with  the  gas,  loosely  corking  it,  and  leaving 
the  whole  till  next  day.  By  that  time  all  caustic  alkali  is  car- 
bonated, so  that  the  alcohol  test  can  be  applied  without  any 
error  due  to  saponification  of  glycerides,  due  correction  being 
made,  if  requisite,  for  the  "  negative  alkalinity  "  of  the  alcoholic 
nitrate  caused  by  the  action  of  the  carbon  dioxide  forming  small 
quantities  of  acid  soap  and  alkaline  carbonate.  This  mode  of 
operating,  however,  obviously  does  not  enable  the  relative  amount 
of  alkali  to  be  distinguished  present  as  hydroxide  and  carbonate, 
&c.,  respectively. 

In  the  case  of  strongly  alkaline  soaps  where  a  slight 
amount  of  error  in  determining  the  total  amount  of  free  alkali 
is  not  material,  two  other  tests  are  applicable,  respectively  desig- 
nated the  "  fatty  acid  titration  test "  and  the  "  salting  out  test/'f 
The  first  of  these  consists  in  determining  the  total  alkali  as 
above,  separating  the  fatty  acids,  and  titrating  them,  reckoning 
the  difference  as  free  alkali.  In  practice  the  unavoidable  experi- 
mental error  of  this  differential  method  is  sometimes  found  to  be 
sufficiently  great  to  render  the  determination  of  minute  quantities 
of  free  alkali  decidedly  uncertain,  so  that  for  nearly  neutral  soaps 
the  method  is  useless.  Moreover,  the  fatty  acids  separated  by 
the  action  of  dilute  aqueous  acid  on  soap  are  sometimes  partly 
soluble  in  water,  so  that  although  the  insoluble  acids  largely 
dissolve  the  soluble  ones  and  bring  them  out  of  solution  in  water 
into  the  supernatant  layer  of  fused  fatty  acids  (as  ether  would 
dissolve  out  similar  matters  from  watery  solution),  still  a  small 
proportion  of  the  soluble  acids  are  apt  to  be  retained  by  the 
water  and  lost,  thus  tending  to  increase  unduly  the  value  of  the 
free  alkali  determination  ;  this  is  especially  noticeable  when 
cokernut  or  palm  kernel  oil  has  been  employed  in  making  the 
soap.  When,  however,  the  free  alkali  is  large,  so  that  a  small 

*  Chemical  News,  lix.  (1889),  p.  280. 

t  Alder  Wright  and  Thompson,  Journ.  Soc.  Chem.  Ind.,  1885,  p.  625. 


500 


OILS,    FATS,    WAXES,    ETC. 


degree  of  possible  error  in   its  determination  is  not  of  great 
importance,  this  method  is  very  convenient. 

The   "  salting  out  test "  is  worked  by  dissolving  a  weighed 
quantity  of  soap  in  hot  water,  adding  salt  so  as  to  throw  the  curd 
out  of  solution,  filtering  off,  and  titrating  the  alkali  in  the  filtrate. 
This  may  be  conveniently  done  in  two  fractions,  one  titrated 
directly  so  as  to  obtain  the  total  alkali  present  (caustic  -f-  car- 
bonated) ;  the  other  treated  with  barium  chloride  in  excess,  and 
the  caustic  alkali  determined  present  in  the  filtrate  from  the 
barium  carbonate,  &c.,  thus  precipitated  (vide  p.  420,  footnote). 
Apart    from    error    in    deficiency    of    the    caustic    alkali    value 
thus  deduced  due  to  unavoidable  absorption  of  carbon  dioxide 
from  the  air  during  the  operations,  a  source  of  error  in  excess  is 
that  hydrolysis  of  the  soap  examined  necessarily  takes  place  to 
an  extent  variable  with  the  temperature,  the  quantity  of  water 
present  relatively   to   the   soap,   the    nature  of  the    fatty  acids 
present,   and    the    amount    of  free    alkali.      When,   however,   a 
uniform   mode  of  manipulating  is   adhered   to,  the   results  got 
with  a  given  kind  of  soap  are  comparable  .amongst  themselves, 
so  that  the  figures  obtained  are  often  of  considerable  practical 
use,  especially  when  corrected  (by  means  of  carefully  made  tests 
using  the  alcohol  process)  so  as  to  get  an  approximate  valuation 
of  the  excess  of  alkali  due  to  the  hydrolytic  action.    For  instance, 
the  following  figures  represent  the  difference  in  amount  of  free 
alkali  found  with  a  variety  of  soaps  according  as  the   alcohol 
test  (A.T.)  or  salting  out  test  (S.O.T.)  was  used  :  the  numbers 
are  reckoned  per  100  parts  of  alkali  combined  with  fatty  acids  as 
soap — i.e.,  if  the  combined  alkali  =  lO'O  and  the  free  alkali  = 
0-52  per  100  of  soap,  this  would  correspond  with  5-2  parts  of 
free  alkali  per  100  of  combined  alkali : — 


Nature  of  Soap  Used. 

A.T. 

S.O.T. 

Excess  of  S.O.T. 
over  A.T. 

Pure  cokernut  oil  soap,  not  strongly  \ 
alkaline,           .          .         .         .         .  / 

5-0 

9-1 

4-1 

Another  sample  of  ditto,     . 

2-8 

58 

3-0 

A  British  toilet  soap,   largely  made  1 
from  cokernut  oil,  .         .         .          .  / 

1-3 

5-8 

4-5 

A  foreign  toilet  soap,   largely  madel 
from  cokernut  oil  (neutral),     .          .  / 

0 

3-5 

3  '5 

A  high-class  American  toilet  soap, 

1-8 

54 

3-6 

A  toilet  soap  largely  made  from  lard  \ 
(neutral),         .         .         .         .         .  / 

0 

3-2 

3-2 

A  second-class  ditto,  chiefly  made  from  ) 

i  -q 

4*8 

0-0 

tallow,     i 

J.     *J 

Tt    O 

—    *7 

A  cotton  seed  oil  soap, 

7'2 

9-8 

2-6 

A  tallow  rosin  (primrose),  . 

1-1 

3-0 

19 

A  neutral  castor  oil  soap,  . 

0 

1-7 

1-7 

A  bleached  palm  oil  soap,  . 

50 

6-4 

1-4 

A  tolerably  alkaline  curd  soap,           .     j 
Pure  stearic  acid  soda  soap  (neutral), 

18-3 
0 

18-3 
07 

0 
0-7 

ROSIN   ACIDS.  501 

When  the  watery  soap  solution  is  tolerably  concentrated  (about 
1  part  by  weight  of  actual  anhydrous  soap  to  10  of  water),  and 
the  soap  itself  contains  a  good  deal  of  free  alkali,  the  error  due 
to  hydrolysis  becomes  small  enough  to  be  quite  negligible  ;  but 
with  a  nearly  neutral  soap  the  hydrolytic  error  becomes  several 
times  as  large  as  the  free  alkali  actually  present. 

Potash  and  Soda. — When  both  alkalies  are  present,  and  it 
is  required  to  determine  their  relative  amount,  several  methods 
of  operating  are  available.  One  of  the  simplest  is  to  decompose 
a  known  quantity  of  soap  with  dilute  hydrochloric  acid,  evaporate 
down  the  watery  nitrate,  convert  potassium  chloride  into  platino- 
ehloride,  and  weigh  this.  In  the  absence  of  more  than  minute 
quantities  of  sulphate,  silicate,  &c.,  the  mixed  alkaline  chloride 
solution  may  be  evaporated  down  and  weighed,  the  chlorine 
contained  determined  (volumetrically  or  otherwise),  and  the  ratio 
of  potassium  to  sodium  calculated  from  the  indirect  results. 
The  soap  may  also  conveniently  be  charred  and  the  alkalies 
dissolved  out  from  the  ash  for  treatment.  When  much  sulphate 
is  present  the  alkalies  should  be  weighed  as  sulphates  and  the 
indirect  determination  made  by  determining  the  barium  sulphate 
yielded  by  the  mixture. 

Rosin  Acids. — It  is  often  of  considerable  importance  to  deter- 
mine with  some  degree  of  approximate  accuracy  the  proportion 
between  the  rosin  acids  and  the  ordinary  fatty  acids  present  in  a 
given  sample  of  soap.  Several  older  methods  have  been  pro- 
posed, none  of  which  yield  very  accurate  results  j  but  more 
recently  two  processes  have  been  introduced  of  a  somewhat  more 
satisfactory  nature,  although  still  leaving  a  good  deal  to  be 
desired.  The  earlier  of  these  is  that  of  Gladding  *  based  upon 
much  the  same  principle  as  the  ordinary  separation  of  oleic  and 
stearic  acids,  viz.,  conversion  into  metallic  salts,  one  soluble  in 
ether,  the  other  insoluble.  The  soap- to  be  tested  is  freed  from 
unsaponified  fat,  &c.,  by  treatment  with  petroleum  spirit ;  or  if 
glycerides  only  are  present  by  heating  with  strong  alcohol  and  a 
few  drops  of  alcoholic  potash  in  excess  of  the  neutralising  amount 
to  effect  complete  saponification.  The  alcoholic  soap  solution  is 
then  agitated  with  powdered  neutral  silver  nitrate  and  ether  in 
a  closed  vessel  for  some  time  (0'5  grm.  fatty  acid,  1  grm.  silver 
nitrate,  and  100  c.c.  of  ethereal  fluid  altogether,  answer  well) : 
after  some  minutes  shaking  flocculent  silver  stearate,  &c.,  sub- 
sides, whilst  silver  resinate  remains  dissolved.  A  known  fraction 
of  the  ether  is  siphoned  off  or  removed  by  a  "  Chattaway  tube  " 
(p.  120)  and  agitated  with  dilute  hydrochloric  acid,  whereby  the 
silver  is  removed  and  an  ethereal  solution  of  rosin  acids  produced, 
by  evaporating  which  the  rosin  acids  are  obtained  in  weighable 
form.  Finally,  a  correction  is  made  for  the  solubility  of  silver 

*  Chemical  Fews,  xlv.  (1882),  p.  159. 


502 


OILS,    FATS,    WAXES,    ETC. 


oleate,  &c.,  amounting  to  a  subtraction  from  the  weight  of  rosin 
acids  obtained  of  23'5  milligrammes  per  100  c.c.  of  ether. 

A  notable  source  of  error  in  this  method  lies  in  the  uncertainty 
of  this  correction,  inasmuch  as  somewhat  widely  different  values 
are  found  with  different  acids — e.g.* 


Nature  of  Fatty  Matters  in  Soap 
Examined. 

Fatty  Matters  Dissolved  (as  Silver  Salt)  in 
100  c.c.  of  Alcoholic  Ether. 

Maximum. 

Minimum. 

General  Average. 

Milligrammes. 

Milligrammes. 

Milligrammes. 

Pure  stearic  acid, 

16-0 

8-0 

11-6 

,,     oleic         ,,              .                        15'0 

9-0 

12-0 

Nearly  pure  palmitic  acid,                  30  '0 

2SO 

29-1 

Cotton  seed  oil,     .         .                        34'0 

20-0 

26-9 

Castor  oil,     ...                       62  "0 

49-0 

53-9 

Cokernut  oil  (fatty  acids  dried 

on  water  bath),          .         .              17*5 

12-0 

14-8 

Cokernut  oil  (fatty  acids  dried    ' 

over  H2S04),     ...             23  '0 

19-0 

21-1 

Stearic   and   oleic    acids,     in 

nearly  equal  proportions,               22  '0 
Stearic  acid  and  cotton  seed  oil, 

IS'O                  J9-1 

in  nearly  equal  proportions, 

... 

... 

25-5 

Oleic  acid  and  cottonseed  oil, 

in  nearly  equal  proportions, 

... 

24-5 

Stearic  acid  and  cokernut  oil 

(water  bath),  in  nearly  equal 

proportions, 

... 

23-4 

Oleic  acid   aud  cokernut   oil 

(water    bath),     in     nearly 

equal  proportions,     . 

... 

... 

25-6 

According  to  the  nature  of  the  fatty  acids,  the  correction  may 
thus  vary  between  8  and  62  milligrammes  in  the  most  extreme 
cases,  and  between  11 '6  and  53*9  for  average  values,  these 
quantities  representing  on  500  milligrammes  of  fatty  acids 
respectively  2-3  and  10 -8  per  cent.  ;  so  that  whilst  2 3 -5  milli- 
grammes (  -  4*7  per  cent.)  is  not  far  from  a  mean  value,  it  is  by 
no  means  equally  applicable  in  all  cases,  f 

*  Alder  Wright  and  Thompson,  Proceedings  of  the  Chemical  Society,  1886, 
p.  175  ;  also  Chemical  News,  vol.  liii.  (1886),  p.  165. 

t  Lewkowitsch  has  subsequently  found  still  wider  discrepancies  between 
the  corrections  necessary  in  the  case  of  stearic  and  oleic  acids — e.g., 

Correction  per  TOO  c.c.  of  Alcoholic  Ether. 

Oleic  acid,          .         .         .      109*0  to  109 '4  milligrammes. 
Stearic  acid,      .         .         .         5  "4  to      5 '8  ,, 

(Journ.  Soc.  Chem.  Ind.,  1893,  p.  503.) 

Hubl  and  Stadler  modify  Gladding's  process  by  precipitating  the  mixed 
silver  salts  from  the  largely  diluted  soap  solution  by  means  of  aqueous 
silver  nitrate,  drying,  and  dissolving  out  silver  resinate  with  ether  in  a 
Soxhlet  tube  (p.  238).  Grittner  and  Szilazi  add  alcoholic  calcium  nitrate 
solution  to  the  alcoholic  soap  solution  to  be  tested,  so  as  to  remove  most  of 


TWITCHELL'S  METHOD.  503 

E.  Twitchell's  method  *  depends  on  the  property  of  ordinary 
fatty  acids  to  form  compound  ethers  when  dissolved  in  alcohol 
and  treated  with  hydrochloric  acid  gas ;  if  the  alcohol  be  absolute 
and  the  solution  saturated  with  the  gas,  the  conversion  is  stated 
to  be  complete  with  fatty  acids,  whereas  rosin  acids  are  not  acted 
upon  at  all ;  with  alcohol  of  only  90  per  cent.,  however,  the 
action  is  not  complete,  several  per  cents,  of  the  fatty  acids 
escaping  conversion.  2  or  3  grammes  of  mixed  acids  are  dissolved 
in  10  volumes  of  absolute  alcohol,  and  dry  hydrochloric  acid 
gas  passed  through  for  45  minutes,  the  vessel  being  cooled 
by  immersion  in  water ;  by  and  bye  the  fatty  ethers  separate, 
floating  on  the  surface.  After  standing  half  an  hour  the  mixture 
is  diluted  with  five  times  its  volume  of  water  and  boiled  till  clear, 
the  ethers  and  rosin  acids  floating  on  the  top;  the  whole  is  shaken 
with  about  50  c.c.  of  light  petroleum  spirit;  after  separation,  the 
hydrocarbon  solution  is  washed  by  shaking  with  water,  and 
finally  shaken  with  5  c.c.  alcohol  and  50  of  water  containing  0-5 
gramme  of  caustic  potash.  The  alkali  dissolves  out  the  rosin 
acids  from  the  hydrocarbon,  leaving  the  fatty  ether  still  dissolved 
therein ;  on  separation  of  the  aqueous  solution  of  resinate,  and 
agitation  with  ether  or  petroleum  spirit  after  acidulation,  the 
rosin  acids  are  obtained  in  solution,  and  may  either  be  weighed 
(after  evaporation  to  dryness)  or  titrated,  assuming  some  par- 
ticular value  for  their  mean  equivalent.!  If  glycerides  are 

the  stearate,  palmitate,  and  oleate  present  by  precipitation ;  the  filtrate  is 
then  treated  with  silver  nitrate  and  ether  as  in  Cladding's  process. 
According  to  Lewkowitsch  (loc,  cit.  supra]  neither  modification  gives  satis- 
factory results,  the  quantity  of  rosin  found  being  generally  below  that 
actually  present  when  soap  made  from  known  mixtures  of  fatty  matters 
and  rosin  are  examined  as  test  samples.  On  the  other  hand,  the  figures 
obtained  by  means  of  Gladding's  original  process  are  generally  several  per 
cents,  too  high,  even  when  the  correction  to  be  used  has  been  separately 
determined  for  the  particular  fatty  acids,  &c.,  used  for  the  test  samples 
employed. 

*  Analyst,  1891,  p.  169;  also  Journ.  Soc.  Chem.  Industry,  1891,  p.  804, 
from  Journ.  Anal,  and  Applied  CTiem.,  vol.  v.,  p.  379. 

t  Test  experiments  made  by  E.  Twitchell  showed  that  when  the  value 
346,  found  as  the  mean  equivalent  weight  of  a  sample  of  colophony,  was 
used  to  calculate  the  result  of  titration  of  the  rosin  acids  isolated  from 
known  mixtures  of  that  colophony  and  fatty  acids,  the  titration  values 
always  came  out  higher  than  those  got  by  weighing  ;  thus — 

Volumetric.  Gravimetric. 

21-40 
20-36 
19-91 


Average  20  "56  18 '93 

Hence  apparently  one  or  two  per  cents,  of  constituents  were  present, 
not  of  acid  nature,  and,  consequently,  not  dissolved  by  the  caustic  potash 
and,  therefore,  not  ultimately  weighed  along  with  the  true  rosin  acids. 
Such  constituents  would  be  weighed  along  with  the  rosin  acids  isolated 


504  OILS,    FATS,    WAXES,    ETC. 

present  in  the  fatty  acid  mixture,  this  does  not  in  any  way 
invalidate  the  rosin  determination,  as  the  glycerides  are  not 
dissolved  out  by  the  alkaline  liquor  along  with  the  rosin  acids. 

Silicate  of  Soda. — The  substance  left  undissolved  by  alcohol  in 
the  determination  of  free  alkali  by  the  "alcohol  test"  (supra),  after 
treatment  of  water  and  nitration,  may  be  titrated  for  alkalinity 
and  then  evaporated  to  dryness  with  a  slight  excess  of  hydro- 
chloric acid ;  the  silicon  dioxide  formed  in  the  event  of  silicate 
being  present  in  the  soap,  is  then  left  undissolved  on  treatment 
of  the  residue  with  water.  Or  a  known  weight  of  soap  may  be 
charred,  and  the  ashes  supersaturated  with  hydrochloric  acid  and 
thoroughly  dried,  so  that  silica  and  carbon  are  left  undissolved 
by  water,  the  latter  being  ultimately  burnt  off. 

Starch,  China  Clay,  Steatite,  Pigments,  &c.— Substances 
of  this  description  other  than  colouring  matters  are  not  often 
found  in  soaps,  but  are  occasionally  added,  especially  to  certain 
varieties  of  fancy  soap — e.g.,  "oatmeal"  soap,  certain  socalled 
"milk"  soaps,  and  the  like.  The  residue  from  the  previous 
examination  for  silicate  and  carbonate,  &c.,  left  undissolved  by 
water  on  treating  the  matters  insoluble  in  alcohol  therewith 
consists  of  these  substances.  Ultramarine,  chrome  green,  ver- 
milion and  similar  pigments  are  sought  after  by  the  appropriate 
tests  suggested  by  the  colour;  starchy  matters  by  means  of 
iodine ;  mineral  constituents  generally  by  incineration ;  and  so  on. 
The  presence  of  such  substances  as  oatmeal,  farina,  &c.,  sometimes 
renders  it  necessary  to  modify  slightly  the  method  for  deter- 
mining fatty  acids  above  described,  where  the  cake  of  fatty  acids 
obtained  is  weighed,  as  it  may  contain  some  of  these  matters 
mechanically  intermixed  ;  to  separate  them  the  cake  is  dissolved 
in  ether,  benzene,  &c.,  and  filtered;  the  residue  is  well  washed 
and  the  nitrate  evaporated  to  dryness. 

Glycerol  and  Sugar.— When  glycerol  is  contained  (as  in 
the  case  of  soft  soaps,  cold  process  soaps,  hydrated  soaps,  &c.)  it 
may  be  determined,  with  a  fair  degree  of  accuracy,  in  a  variety 

by  Gladding's  process.  Lewkowitsch  finds  (Journ.  Soc.  Chem.  Ind.,  1893, 
p.  505)  that  the  mean  equivalent* of  different  samples  of  commercial  rosin 
varies  within  somewhat  wide  limits ;  thus,  with  six  samples  of  American 
rosin  values  were  found  varying  between  340 '8  and  364,  with  an  average  of 
348 "3.  Hence,  the  percentage  of  rosin  found  by  titration  can  only  be 
regarded  as  a  somewhat  rough  approximation.  On  the  other  hand, 
Twitchell's  process,  applied  to  pure  stearic  acid  and  other  fatty  acids  and 
mixtures  free  from  rosin,  indicated  from  1'07  to  3'67  per  cent,  of  that 
substance,  the  products  obtained  being  weighed ;  whence  it  would  seem  that 
the  quantity  of  rosin  apparently  found  in  a  given  sample  of  soap  by  Twitchell's 
process  would  be  too  high,  and  that  a  correction  should  be  made  to  allow 
for  this  source  of  error  (probably  incomplete  conversion  of  fatty  acids- 
into  compound  ethers,  or  subsequent  decomposition  of  compound  ethers) 
In  practice,  however,  the  quantity  of  rosin  actually  found  is  generally 
somewhat  beloiv  that  known  to  be  present  when  test  samples  of  known 
composition  are  examined. 


GLYCEROL    AND    SUGAR.  505 

of  ways  in  the  absence  of  sugar ;  but  in  presence  of  sugar  its 
accurate  determination  is  not  easy.  If  sugar  be  not  present,  one 
of  the  simplest  methods  of  procedure  is  to  decompose  the  soap 
with  a  slight  excess  of  sulphuric  acid,  and  after  separating  the 
fatty  acids  to  render  neutral  or  slightly  alkaline  with  sodium 
carbonate,  evaporate  to  dryness,  and  dissolve  out  the  glycerol 
from  the  sodium  sulphate,  &c.,  by  absolute  alcohol :  the  residue 
left  on  evaporating  off  the  alcohol  may  be  weighed,  and  any 
inorganic  matters  present  determined  by  incineration  and  sub- 
tracted. The  crude  glycerol  may,  preferably,  be  purified  as 
described  on  p.  523;  or  it  may  be  converted  into  acetin  by 
acetic  anhydride  (pp.  186,  516);  or  if  sufficiently  free  from  other 
organic  substances  it  may  be  determined  by  the  dichromate 
process  (p.  522),  or  oxidised  to  oxalate  (p.  519).  A  little  gly- 
cerol is  volatilised  during  the  latter  part  of  the  evaporation  ; 
hence  when  either  of  these  two  latter  methods  is  employed, 
instead  of  evaporating  the  aqueous  solution  to  complete  dryness, 
it  may  preferably  be  only  partially  concentrated.  Muter's  method 
consists  in  treating  with  copper  sulphate  and  caustic  soda,  the 
copper  kept  in  solution  being  determined  colorimetrically  or  by 
potassium  cyanide  (p.  523),  parallel  observations  being  made 
with  liquids  treated  in  just  the  same  way  after  addition  of  known 
quantities  of  glycerol  solution  from  a  burette,  so  as  to  afford  the 
means  of  calculating  the  glycerol  present  from  the  amount  of 
copper  kept  in  solution.  In  general  the  glycerol  may  be  thus 
estimated  conveniently  in  the  watery  fluid  left  after  determining 
total  alkali  and  fatty  acids  (supra).  When  sugar  is  present  this 
is  inverted  by  heating  with  dilute  hydrochloric  or  sulphuric 
acid ;  the  liquid  is  then  rendered  alkaline  and  copper  sulphate 
added  in  excess,  and  the  sugar  deduced  from  the  amount  of  pre- 
cipitated cuprous  oxide ;  the  alkaline  liquid  containing  glycerol 
and  the  products  of  the  oxidation  of  the  sugar  may  be  tested  for 
glycerol  by  determining  the  amount  of  dissolved  copper  as  before, 
checking  the  results  by  means  of  similar  tests  with  liquids  con- 
taining known  quantities  of  sugar  +  glycerol;  the  results, 
however,  are  apt  to  be  only  approximate  even  with  the  greatest 
care.  Instead  of  determining  sugar  by  the  copper  reduction  pro- 
cess the  polariscope  may  be  employed.  Knowing  the  amount  of 
sugar  present  and  the  specific  gravity,  the  proportion  of  glycerol 
present  may  be  approximately  calculated  in  the  case  of  a  liquid 
containing  no  other  substances  in  solution. 

Volatile  Substances  other  than  Water. — Sometimes  a 
transparent  soap  contains  alcohol,  the  proportion  of  which  is 
desired  to  be  known ;  other  volatile  constituents  are  sometimes 
present  in  other  kinds  of  soap  —  e.g.,  carbolic  acid,  thymol, 
camphor,  &c.  In  such  cases  special  methods  must  usually  be 
resorted  to  to  determine  the  volatile  substance,  dependent  on  its 
nature.  Alcohol,  if  in  quantities  above  inconsiderable  traces,  may 


506  OILS,    FATS,    WAXES,    ETC. 

be  determined  by  dissolving  in  water  a  sufficient  quantity  of 
soap,  adding  salt,  filtering  off  say  one  half  of  the  total  fluid,  and 
distilling  until  about  half  has  passed  over;  this  distillate  is  simi- 
larly redistilled,  and  ultimately  the  quantity  of  alcohol  inferred 
either  from  the  specific  gravity  of  the  final  distillate,  or  by 
oxidising  with  chromic  acid,  ifec.  The  following  method  of 
determining  phenoloids  is  recommended  by  A.  H.  Allen  * : — 
5  grammes  of  soap  are  dissolved  in  hot  water,  20  to  30  c.c.  of  a 
10  per  cent,  solution  of  caustic  soda  added,  and  the  whole  cooled 
and  agitated  with  ether  to  dissolve  hydrocarbons.  The  alkaline 
liquor  is  separated  and  treated  with  excess  of  strong  brine ; 
fatty  acid  soaps  are  precipitated,  but  sodium  phenolate  and 
cresylate,  etc.,  remain  in  solution ;  the  liquid  is  filtered  and 
the  precipitate  washed  with  brine,  and  the  nitrate  and  washings 
diluted  to  a  litre.  100  c.c.  of  the  solution  (representing  0'5 
gramme  of  soap)  are  acidulated  with  sulphuric  acid,  and  the 
solution  (clear  if  fatty  acids  have  been  thoroughly  removed) 
titrated  with  bromine  water  standardised  by  means  of  carbolic 
iicid  (or  cresylic,  &c. ),  operating  in  the  same  way ;  when  enough 
bromine  has  been  added  to  cause  all  the  phenoloids  to  become 
converted  into  tribromo  derivatives,  the  yellow  tint  due  to  excess 
of  bromine  becomes  visible.  By  treating  the  other  900  c.c.  of 
solution  with  sulphuric  acid  and  excess  of  bromine,  and  agitating 
with  successive  small  quantities  of  carbon  disulphide,  the  tri- 
bromo derivatives  may  be  dissolved  out  and  examined  after 
evaporation  of  the  solvent.  Pure  phenol  (crystallised  "  carbolic 
acid")  gives  nearly  colourless  long  needles  of  tribromophenol, 
whereas  cresylic  acids  give  deep  yellow,  orange,  or  red  difficultly 
crystallisable  or  non-crystalline  products  ;  so  that  the  character  of 
the  phenoloids  present  may  be  ascertained,  as  well  as  the  amount. 

The  following  general  scheme  represents  a  selection  from  the 
-above  processes  applicable  in  most  cases  : — 

Dry  10  grammes  of  average  sample,  finally  at  120°,  and  reckon 
the  loss  of  weight  as  water. 

Exhaust  the  residue  with  light  petroleum  spirit,  and  examine 
the  extract  for  unsaponified  glycerides,  hydrocarbons,  spermaceti, 
wax,  cholesterol,  &c. 

Treat  the  exhausted  residue  with  water  and  excess  of  standard 
^nitric)  acid  ;  separate  and  weigh  the  fatty  acids,  and  subject 
them  to  such  further  examination  as  may  be  required,  more 
especially  as  regards  the  presence  of  rosin  acids.  Back-titrate 
the  aqueous  liquor  so  as  to  determine  the  total  alkali,  using 
alkaline  solution  free  from  sulphate  and  chloride.  Determine 
sulphate  and  chloride  in  the  neutralised  liquid ;  also  glycerol  and 
sugar  if  present ;  and  potassium  if  required. 

Treat  5  grammes  of  average  sample  with  hot  strong  alcohol,  and 
titrate  acidity  or  alkalinity  of  filtered  solution  :  dissolve  the 
*  Commercial  Organic  Analysis,  2nd  edition,  vol.  ii.,  p.  255. 


CAILLETET'S  METHOD.  507 

undissolved  part  in  water  and  titrate  for  carbonated  alkali,  &c., 
so  as  ultimately  to  deduce  the  free  alkali.  Examine  the  sub- 
stances not  dissolved  by  alcohol  for  silica,  clay,  starch,  pigments, 
and  similar  substances.*  If  unsaponified  glycerides  and  caustic 
alkali  be  simultaneously  present,  the  latter  should  be  carbonated 
before  dissolving  the  soap  in  alcohol,  otherwise  a  deficiency  in 
the  total  "  free  alkali  "  will  result  (supra,  p.  499). 

An  objection  to  this  mode  of  operation  is  that  if  any  caustic 
alkali  be  contained  in  the  soap,  it  becomes  more  or  less  carbonated 
during  the  drying,  so  that  an  incorrect  valuation  of  caustic  alkali 
results.  When  much  caustic  alkali  is  present,  it  may  be  deter- 
mined by  the  salting  out  test  (supra),  adding  barium  chloride 
to  convert  alkaline  carbonate  into  chloride,  and  filtering  before 
titrating  (compare  p.  500). 

Instead  of  decomposing  the  soap  dissolved  with  alcohol  with 
excess  of  standard  acid,  and  back-titrating  after  separation  of 
fatty  acids,  the  alcoholic  solution  may  be  rendered  neutral  to 
phenolphthalein,  and  then  directly  titrated  with  a  standard 
mineral  acid  solution,  using  methyl  orange  as  an  indicator, 
organic  fatty  acids  having  no  reaction  on  this  substance:  per- 
fectly sharp  results  are  thus  obtainable  (Allen). 

Cailletet's  method  of  Analysis. t — For  determinations  where 
speed  is  indispensable  but  minute  accuracy  unnecessary,  a  con- 
venient process  has  been  proposed  by  Cailletet  for  the  determin- 
ation of  fatty  acids  and  alkali.  A  tube  holding  50  c.c.  and 
divided  into  100  parts  is  provided,  into  which  are  introduced  10  c.c. 
of  diluted  sulphuric  acid  of  known  strength  (about  four  times 
normal),  20  c.c.  of  oil  of  turpentine,  and  10  grammes  of  the  soap 
in  shavings.  The  tube  is  closed  with  a  stopper  or  cork  and  well 
shaken  up  ;  when  all  the  soap  is  decomposed  it  is  allowed  to 
stand,  and  the  volume  of  the  turpentine  solution  of  fatty  acids 
read  off.  Subtracting  the  20  c.c.  of  turpentine  used,  the  differ- 
ence gives  the  volume  of  the  fatty  acids  :  thus,  if  the  turpentine 
solution  occupied  50  divisions  =  25  c.c.,  the  fatty  acids  would 
represent  25  —  20  =  5  c.c.  per  10  grammes  of  soap.  Assuming 
the  specific  gravity  of  the  fatty  acids  to  be  n,  their  weight  would 
be  5  x  n  grammes  =  50  x  n  per  cent,  by  weight.  The  alkali 
is  obtainable  by  back-titrating  the  excess  of  acid. 

Cailletet  gives  the  following  values  for  n  in  the  case  of  soaps 
of  different  kinds,  experimentally  determined  by  noting  the 

*  Instead  of  weighing  up  two  portions  of  soap,  one  portion  (preferably  of 
10  grammes)  may  be  employed  for  all  the  determinations,  being  first  dried, 
then  exhausted  with  petroleum  ether  to  extract  fat,  and  then  treated 
(still  in  the  Soxhlet  tube)  with  alcohol  to  dissolve  out  soap,  glycerol,  &c. 
The  alcoholic  extract  thus  obtained  is  titrated  for  acidity  or  alkalinity, 
then  largely  diluted  with  hot  water  and  decomposed  with  standard  acid  so 
as  to  obtain  fatty  acids  and  total  alkali ;  whilst  the  residue  undissolved  by 
alcohol  is  tested  for  alkali,  silicate,  sulphate,  chloride,  starch,  pigments,  &c. 

f  Bulletin  Soc.  Ind.,  Mulhouse,  xxix.,  p.  8. 


508 


OILS,    FATS,    WAXES,    ETC. 


increment  in  volume  of  turpentine  oil  as  above  indicated,  and 
directly  determining  the  percentage  by  weight  of  fatty  acids  in 
another  portion  of  the  same  soap  : — 

Specific  Gravity  of  Fatty  Acids. 

Olive  oil  (Marseilles)  soap 0'9188 

Cokernut  oil  soap,    .......         0'9400 

Palm  oil  soap, 0'9220 

Tallow  soap 0'9714 

Oleic  acid  soap, 0'9003 

In  the  case  of  rosin  soaps,  the  rosin  acids  do  not  readily  dis- 
solve in  the  turpentine,  20  c.c.  only  increasing  0-15  c.c.  in  volume 
by  virtue  of  the  rosin  acids  dissolved,  whilst  a  bulky  layer  of 
undissolved  rosin  collects  below  the  turpentine. 

Calcium  Salt  Test. — A  rough  method  of  arriving  at  the  value 
of  a  given  soap  is  to  dissolve  in  dilute  alcohol  and  determine  the 
quantity  of  the  solution  requisite  to  be  added  to  a  known  volume 
of  a  solution  of  calcium  chloride,  sulphate,  &c.,  so  as  to  produce 
a  permanent  lather,  as  in  Clark's  test  for  the  hardness  of  water  ; 
a  parallel  determination  being  made  with  a  standard  sample  of 
similar  soap  of  known  composition,  the  ratio  between  the  volumes 
of  the  two  soap  solutions  used  gives  approximately  their  relative 
detergent  value.  The  soap  solutions  may  be  conveniently  made 
of  the  strength  of  10  grammes  per  litre  ;  the  lime  salt  solution 
maybe  made  by  dissolving  0'2  gramme  of  pure  calcium  carbonate 
in  dilute  hydrochloric  acid,  evaporating  to  dry  ness  on  the  water 
bath  to  expel  excess  of  acid,  dissolving  the  residue  in  distilled 
water  and  diluting  to  a  litre ;  the  solution  consequently  repre- 
sents 20  milligrammes  of  CaCO3  per  100  c.c.  or  14  grains  per 
gallon  (14°  of  hardness  on  Clark's  scale). 

The  folio  wing  analyses  represent  the  composition  of  a  consider- 


Best  Tal- 
low Curd, 
London 
make. 

Bleached 
Palm  Oil, 
London 
make. 

Marine 
Soap,  non- 
siiicated. 

Marine 
Soap, 
silicated. 

Imitation 
Castile 
Soap, 
English. 

Fatty  anhydrides,  . 
Combined  alkali  (Na20), 

66-60 
7-51 

66-20 
7-83 

32-00 
5-20 

13-50 
2-27 

61-45 
8-46 

Freealkali(includingthat  } 
present  as  silicate),      .  J 

•50 

•40 

2-25 

8'36 

1-16 

Silica  (Si02),  . 

... 

10-50 

Sodium  chloride,     . 

1-35 

2-05 

765 

5-05 

1-17 

Sodium  sulphate,    . 

•20 

traces 

1-45 

•35 

1-23 

Water,  carbonic  acid,  and  j 

insoluble  matters,  pig-  > 

23-84 

23-52 

51-45 

59-97 

26-53* 

ments,  &c.,  .         .         .  ) 

100-00 

100-00 

100-00 

100-00 

100-00 

Percentage  of  true  soap, 

74-11 

74-03 

37-20 

15-77 

69-91 

Mean   molecular   weight! 
of  fatty  acids,       .         .  / 

284 

271 

200 

197 

234 

Including  '74  per  cent,  of  insoluble  pigments. 


MANUFACTURERS',  HOUSEHOLD,  AND  LAUNDRY  SOAPS.       509 

able  variety  of  British  and  colonial  manufacturers'  and  other 
scouring  and  laundry  soaps.  Where  no  analyst's  name  is  men- 
tioned, the  analyses  were  made  by  the  author. 


"Prim- 

"Cold 

"Cold 

Oleic  Acid 

London 
make. 

"Ivory," 
Canadian.* 

Water," 
English. 

Water," 
Canadian.* 

Soap, 
London 
make. 

Fatty  anhydrides,  . 
Resinous  anhydrides, 

|     46-88 
\     15  -40 

43-33 
25-00 

43-70 
22-00 

45-85 
24-00 

62-71 

Combined  alkali  (Na20), 

7-12 

7-72 

9-28 

8-00 

7-36 

Sodium  carbonate,  . 

•14 

2-64 

•58 

2-22 

•68 

,,       chloride.     . 

•14 

,,       sulphate,    . 
Water  with  minute  quan- 

•07 

21-31 

24-44 

1993 

29-25 

tities  of  insoluble  mat- 

on n- 

ters,  lime,  ferric  oxide, 

&r> 

100-00 

100-00 

100-00 

100-00 

100-00 

Percentage  of  true  soap, 

69-40 

76-05 

7498 

72-07 

70-07 

Free  alkali  (NTa20), 

•08 

1-54 

•34 

1-30 

•40 

Mean   molecular  weight  \ 
of  fatty  acids,  &c.  ,        .  / 

280 

283 

230 

280 

273 

MANUFACTURERS'  SOAPS  (C.  Hope). 


§ 

;_r~ 

;_. 

| 

*..s 

,  i 

ti  &Tii 

c'O 

o" 

d    -to 

^3^'-->  0! 

so 

•jjsjOd 

fr 

^o  « 

•2  §  S  « 

§S 

^^"c° 

^0 

O 

•e—  2 

s    ^ofe  £ 

f^  2 

•e    -ei'S 

*s  s*» 

-^  Cl^* 

2^  fifc^^ 

3  . 

3  C?  fl  02 

£^d 

Q 

•—  pq      ^ 

?"3 

g 

? 

S«i5 

^ld 

?! 

Fatty  anhydrides  and  rosin, 

71-30 

62-66 

59-28 

38-89 

19-42 

60-90 

Soda  (Na20),  combined  as  soap, 
Free  alkali  (Na2O),  including 

7-98 

7-27 

6-65 

5-76 

3-11 

7-22  i 

carbonate  and  silicate, 

1-23 

•80 

•40 

2-91 

698 

•10 

Sodium  chloride,  . 

•36 

•76 

•47 

1-78 

513 

•46 

Sodium  sulphate, 

•30 

•30 

•13 

•72 

•35 

•12 

Silica,   ..... 

1-07 

•06 

•42 

640 

900 

•04 

Lime,  oxide  of  iron,  &c.  , 

•16 

•16 

•16 

03 

•16 

•02 

Water,           .... 

17-44 

28-20 

32-35 

38-70 

5332 

3122 

Total, 

99-84 

100-21 

99-86 

95-1  9t 

97-47t 

100  08 

Actual  soap  present, 

79-28 

69-93 

65-93 

4465 

22-53 

68-12 

*  Exhibited  in  the  "Colonial  and  Indian  Exhibition,"  London,  1886. 
For  analyses  of  various  of  the  Colonial  soaps,  made  by  the  author,  vide 
"Colonial  and  Indian  Exhibition  Reports — Oils  and  Fats"  (Leopold  Field). 

fOlycerol  present,  but  not  determined. 


510 


OILS,    FATS,    WAXES,    ETC. 


MANUFACTURERS'  SOAPS  (Lant  Carpenter}. 


"Primrose"  Soap. 

"Cold 
Water" 
Soap. 

"  Neutral 
Curd." 

"Oil" 
Soap, 
"Oleic 
Acid." 

Genuine 
Rosin  Soap 
(South  of 

Watered 
&  Silicated 
(North  of 

England). 

England). 

Fatty  acids,*  .         .         .          62  -3 

42-66 

70-2 

67-9 

68-6 

Combined  soda  (Na,0),              6  '7 

5-4] 

7-3 

7-0 

7-88 

"  Free  alkali  "  (Na20), 

1-21 

1-8 

nil. 

1-0 

Silica,      .... 

•94 

1-6 

... 

... 

Neutral  salts,          .         .              '2 

•55 

•4 

•2 

i-o 

Water,   .         .         .         .          32  '8 

50-40 

22-0 

28-0 

21-0 

Total,     .         .         .        102-0 

101-17 

103-3 

103-1 

99-48 

PHARMACEUTICAL  SOAPS  (M.  Dechan). 


Sapo 

S.  Castil. 

8.  Ani- 

durus, 

albus, 

Mottled 

malis, 

S.  Mollis, 

Hard 

White 

Castile. 

Tallow 

Soft  Soap. 

Soap. 

Castile. 

Soap. 

Fatty  acids,*. 

81-50 

76-70 

68-10 

78-30 

48-50 

Combined  alkali,     . 

9-92 

9  14 

8-90 

9-57 

12-60 

Free  alkali, 

•08 

•09 

•19 

•28 

•30 

Silica,     .... 

•15 

•17 

Sulphates  and  chlorides, 
Matters  insoluble  in  alcohol, 

•28 
•50 

•36 
•60 

•63 
1-30 

•47 
1-10 

•93 
1-60 

Other  insoluble  matter,  . 

•20 

•90 

•80 

•40 

1-00 

Water,    .... 

10-65 

13-25 

21-70 

12-50 

39-50 

103-13 

101-04 

101-77 

102-62 

104-68 

SOFT  SOAPS  (Ure). 


London 
Soft 
Soap. 

Belgian 
Green 
Soap. 

Scotch. 

Rape  Oil 

Soft 
Soap. 

Olive  Oil 
Soft 
Soap. 

Fatty  acids,    . 
Dry  potash  (K20), 
Water,  salts,  glycerol,  &c., 

45-0 
8-5 
46-5 

36-0 

7-0 
57  0 

47-0 
8-0 
450 

51-7 

10-0 

38-3 

480 

10-0 

42-0 

100-0 

100-0 

100-0 

100-0 

100-0 

In  general,  similar  partial  analyses  of  soft  soaps  meet  the 
objects  in  view,  inasmuch  as  such  soaps  are  generally  purchased 
in  quantity  under  contract  either  to  contain  a  given  percentage 
(40,  50,  &c.)  of  fatty  acids  producible  on  decomposition  by  a 
mineral  acid,  or  to  lose  not  more  than  a  given  percentage  in 
weight  (water)  on  drying  completely ;  the  degree  of  alkalinity  is 
usually  judged  by  the  u  touch  "  or  taste  of  the  sample,  the  tongue 
being  regarded  as  a  sufficiently  delicate  indicator  for  such  pur- 
poses. When  more  definite  information  is  required  the  methods 
*  Not  calculated  to  fatty  anhydrides. 


ANALYSES    OF    TOILET    SOAPS. 


511 


above  described  are  applicable ;  thus  the  water  is  directly  deter- 
mined by  drying  in  a  sand  bath  (p.  494) ;  the  total  fatty  acids, 
free  alkali,  combined  alkali,  unsaponitied  oil,  and  matters  insol- 
uble in  water  (such  as  starch  added  to  simulate  "figging,"  &c.) 
by  the  respective  processes  above  detailed ;  the  rosin  acids  by 
Gladding's  process  (p.  501)  or  Twitchell's  method  (p.  503);  silicate 
by  incineration  and  analysis  of  the  mineral  constituents  of  the 
ash  ;  and  so  on. 

In  the  case  of  household  and  laundry  soaps  it  is  to  be  noticed 
that  the  physical  consistence  of  the  substance  is  in  many  cases 
of  as  much  importance  as  its  chemical  constitution.  From  the 
consumer's  point  of  view  what  is  required  in  the  case  of  a  hard 
soda  soap  is  an  article  from  which,  during  use,  no  more  is  dis- 
solved or  abraded  than  is  just  requisite  for  the  object  in  view. 
If  the  soap  be  of  too  soft  a  consistency  (either  through  over 
watering,  or  bad  selection  of  materials),  a  much  larger  amount 
is  rubbed  on  the  clothes,  <fcc.,  to  be  washed  or  scoured  than  is 
absolutely  necessary,  leading  to  much  waste.  On  the  other 
hand,  pure  tallow  curd  soaps  largely  boiled  down  are  so  hard  as 
only  to  rub  off  and  lather  with  difficulty.  With  manufacturers' 
soaps  intended  to  be  dissolved  in  water  before  use  (e.g.,  soft  soap 
for  wool  scouring,  &c.),  the  rate  of  solution  must  be  sufficient 
for  the  purpose ;  whilst  hydrocarbons  and  other  insoluble 
impurities  which  might  spot  and  stain  goods  must  be  absent 
from  soaps  intended  for  treatment  during  dyeing  and  subsequent 
operations. 

TOILET  SOAPS. 


High-class 
Milled 
Soap  of 
Conti- 
nental 
make. 

High-class 
Opaque 
Soap, 
English. 

Inferior 
Ouaque 
Soap, 
English. 

Transparent  Soaps. 

Made  by 
Cold 
Process. 

Made  hy  Spirit 
Process. 

Sugared. 

Genuine, 
not 
Sugared. 

Fatty  anhydrides,  . 
Uncombined  rosin  and 
unsaponified  fats, 
Combined  alkali,    . 
Sodium  carbonate, 
Sugar,    . 
Glycerol, 
Water  and  minute 
quantities  of  salts, 

Percentage   of  true 
soap,    . 
Free  alkali  (Na20), 
Mean  molecular 
•\veight  of  fatty  acids, 

83-60 

1-00 
9-80 
•24 

5-36 

GO  -20 

G-9S 
•17 

3-00 
29-65 

6500 

8-91 
1-73 

6-00 
18-36 

38-90 

•40 
5-57 
3-80 
28-00 
3-00 

20-33 

65-60 

3'00 
7-73 

nil. 
14-00 

9-67 

68-10 

3-20 

7-62 
•20 
nil. 
7-00 

13-88 

100-00 

100-00 

100-00 

100-00 

100-00  100-00 

93-40 
•14 

274 

67'18 
•10 

276 

73-91 
1-01 

228 

44-47 
2-22 

225 

73-33 

nil. 

272 

75-72 
nil. 

286 

512  OILS,    FATS,    WAXES,    ETC. 

In  the  case  of  "  toilet "  soaps,  the  most  important  quality  is 
that  of  furnishing  a  sufficient  lather  without  at  the  same  time 
causing  the  application  of  too  alkaline  a  substance  to  the  skin ; 
the  small  amount  of  free  alkali  developed  by  hydrolysis  when  a 
tablet  of  soap  is  rubbed  on  the  skin  or  between  the  hands  is 
practically  insensible,  excepting  to  extremely  sensitively  skinned 
persons  who,  in  consequence,  are  rarely  able  to  use  soap  in  any 
form  without  suffering  more  or  less  irritating  effects.  Such 
individuals  are  comparatively  rare;  but  a  much  larger  portion 
of  the  population,  especially  ladies  and  young  children,  are  prone 
to  suffer  inconvenience  (particularly  in  windy  and  wintry  weather) 
through  the  use  of  soap  containing  more  than  traces  of  free 
alkali ;  to  some  extent  this  inconvenience  may  be  mitigated  by 
introducing  into  the  soap  such  substances  as  vaseline,  spermaceti, 
or  even  purified  lard,  &c.,  whereby  a  film  of  greasy  or  unguent- 
like  substance  is  left  adherent  to  the  skin,  or  at  least  pressed 
into  its  pores  (vide  p.  478) ;  but  a  far  safer  plan  is  so  to  prepare 
or  refine  the  soap  as  to  ensure  that  it  shall  not  contain  any 
material  amount  of  free  alkali.  The  author  has  proposed*  to 
classify  toilet  soaps  into  three  grades  from  this  point  of  view, 
viz.  : — 

First  grade. — Soaps  containing  a  total  amount  of  "  free  alkali  " 
not  exceeding  JQ-  (2*5  per  100)  of  the  alkali  present  combined  with 
fatty  anhydrides  as  soap  ;  so  that  if  the  soap  contained  8*0  per 
cent,  of  combined  alkali,  the  free  alkali  would  not  exceed  0*2  per 
cent. 

Second  grade. — Soaps  where  the  "free  alkali"  ranges  between 
•Jg-  and  -£Q  (2-5  to  7 '5  per  100)  of  that  present  as  actual  soap — 
i.e.,  for  a  soap  containing  S'O  per  cent,  of  combined  alkali  the 
free  alkali  would  be  between  0'2  and  0*6  per  cent. 

Third  grade. — Soaps  where  the  "free  alkali"  exceeds  -£§  (7*5 
per  100)  of  that  present  as  actual  soap. 

It  is  to  be  borne  in  mind,  however,  that  other  possible  ingre- 
dients besides  alkali  are  apt  to  be  detrimental  to  sensitive  skins: 
of  these  sugar  (almost  invariably  present  in  transparent  soaps)  is 
the  one  most  certainly  known  to  be  noxious  (pp.  478,  480,  482); 
but  there  is  also  reason  for  supposing  that  some  extremely 
highly  perfumed  soaps  may  exert  a  more  or  less  marked  irri- 
tating action  of  the  same  kind  in  virtue  of  the  comparatively  high 
proportion  of  essential  oils,  etc.,  present  (p.  480),  even  though 
entirely  destitute  of  free  alkali,  and  containing  no  sugar. 

When  a  soap  (toilet,  household,  or  manufacturer's)  contains 
an  amount  of  glycerol  approximately  corresponding  with  that 
equivalent  to  the  fatty  acids  found  (92  parts  glycerol  for  3  x  n 
parts  of  fatty  acids  of  mean  molecular  weight  n),  the  probability 

*" Cantor  Lectures,"  Society  of  Arts,  Jo-urn.  Sor.  Arts,  vol.  xxxiii., 
p.  112i  (18S5),  where  also  various  other  analyses  of  toilet  soaps  are  given. 


MANUFACTURE    OF   GLYCERINE.  513 

is  that  the  soap  has  been  prepared  by  a  cold  process  :  such  a  soap, 
for  instance,  might  yield  fatty  acids  of  mean  molecular  weight 
270,  in  which  case  100  parts  of  fatty  acids  would  correspond  with 

~Q — o7n    =  11*3  parts  of  glycerol,  if  triglycerides  were  employed, 
o  x  2i  i  U 

Larger  proportions  of  glycerol  can  only  be  contained  in  cases 
where  extra  glycerol  has  been  added.  On  the  other  hand,  as 
soaps  prepared  by  boiling  and  salting  out  contain  no  glycerol  at 
all,  the  presence  of  smaller  proportions  of  glycerol  suggests 
either  that  the  soap  mass  is  a  mixture  of  hydrated  soaps  or  cold 
process  soaps  (Chap,  xx.)  and  boiled  soaps,  or  that  free  oleic  acid, 
&c.,  has  been  employed  along  with  glycerides  in  its  manufacture. 


CHAPTER    XXII. 

GLYCEROL  EXTRACTION— MANUFACTURE  OF 
GLYCERINE. 

IN  the  manufacture  of  soaps  and  "  stearine"  for  candlemaking, 
large  quantities  of  glycerol  *  are  produced  as  product  comple- 
mentary to  the  fatty  acids  formed  by  saponification  of  the  oils 
and  fats  employed.  Until  comparatively  recently,  much  of  the 
glycerol  thus  formed  was  wasted,  being  run  away  along  with 
other  watery  fluids  into  the  drains,  <fcc. ;  but  since  the  introduc- 
tion of  various  applications  for  which  glycerol  is  suited,  more 
especially  the  manufacture  of  dynamite  and  other  explosives, 
much  of  the  substance  formerly  thrown  away  as  worthless,  is 
now  extracted  and  utilised  by  processes  which  substantially 
consist  of  evaporation  so  as  to  remove  saline  matters  by 
crystallisation,  and  distillation  with  superheated  steam  of  the 
final  mother  liquors. 

The  "  sweet  water  "  obtained  in  the  saponification  of  glycerides 
by  lime  in  the  autoclave  or  open  pan  processes  (pp.  365,  373),  is 
one  of  the  most  eligible  sources  of  commercial  glycerine  when  re- 
quired of  high  purity ;  the  distillation  of  fatty  matters  by  means  of 
superheated  steam,  so  as  to  hydrolyse  them  and  form  fatty  acids 
and  glycerol  (p.  385),  furnishes  a  still  purer  raw  product ;  if  the 
temperature  of  distillation  be  too  high  (above  310°  to  320°  C.), 
more  or  less  decomposition  of  glycerol  into  water  and  acrolein 
(acrylic  aldehyde)  results. 

The  watery  glycerol  solutions  thus  obtained  are  concentrated 

*  As  already  stated  (p.  110)  the  word  "glycerol"  is  employed  in  the 
present  work  to  denote  the  chemical  substance  C3H5(OH)3,  and  the  term 
"  glycerine  "  to  indicate  commercial  products  more  or  less  largely  consisting 
of  glycerol  in  varying  states  of  purity. 

33 


514  OILS,    FATS,    WAXES,    ETC. 

by  evaporation,  preferably  not  in  ordinary  pans,  but  by  special 
devices  analogous  to  those  used  in  the  sugar  industry,  where  a 
series  of  convoluted  tubes  or  hollow  plates  heated  by  the 
internal  admission  of  steam,  are  made  to  revolve,  so  that  the 
tubes  or  plates  partly  dip  into  the  fluid  to  be  evaporated  and 
carry  upwards  an  adherent  film  thereof  as  they  revolve,  which 
film  rapidly  loses  water  by  evaporation  whilst  the  part  of  the 
tube  or  plate  to  which  it  adheres  is  exposed  to  the  air  after 
emerging  from  the  liquid,  especially  if  the  whole  arrangement  is 
placed  inside  an  exhausted  vessel  or  "  vacuum  pan." 

When  the  glycerol  solution  is  sufficiently  concentrated,  it 
is  decolorised  by  treatment  with  animal  charcoal,  and  again 
distilled  by  means  of  superheated  steam,*  the  processes  being 
repeated  several  times  for  products  of  high  purity,  such  as  the 
glycerine  required  for  the  manufacture  of  nitroglycerine  for 
dynamite  arid  similar  explosives.  Glycerines  of  the  highest 
degree  of  purity  are  best  obtained  by  crystallising,  draining 
off  the  unsolidified  portion  by  a  centrifugal  machine,  and  melt- 
ing the  residual  crystals. 

The  extraction  and  purification  of  glycerol  from  soap  leys  is  a 
much  more  troublesome  matter,  not  so  much  because  of  the  dis- 
solved salt,  &c.,  which  requires  to  be  fished  out  as  the  evapora- 
tion proceeds,  as  because  various  organic  impurities  derived 
from  the  fats,  &c.,  are  also  present.  C.  T.  Kingzett  f  found  the 
following  compositions  in  the  case  of  the  salts  deposited  on 
evaporation,  and  of  the  evaporated  mother  liquor  of  specific 
gravity  1-236:— 

SALTS. 

Sodium  chloride,          .             .             .             .  78 '12 

Sodium  sulphate,          .             .             .             .  8 '61 

Sodium  carbonate,        .             .             .             .  .           2-61 

Insoluble  organic  matter,         .             .             .  .           0'22 

Glycerol  and  other  organic  soluble  matters,  .           3 '55 

Water,              ......  7'50 

100-61 
CRUDE  GLYCERINE. 

Water,  .  .  .         7  '53  pounds  per  gallon. 

Glycerol,     .  .  .2-04  „ 

Salts,          .  .2-78 

12-35 

The  removal  of  the  inorganic  salts  and  the  saponaceous, 
resinous,  and  albuminous  organic  matters  contained  in  the  crude 
leys  may  be  more  or  less  completely  effected  in  a  variety  of 
ways  the  subject  of  a  number  of  patents.  Thus,  by  acidulating 
the  liquor  any  soap  is  decomposed,  and  fatty  and  resinous  acids 

*  An  improved  form  of  glycerine  rectifying  apparatus  has  been  patented 
by  R.  O.  Unglaub  (Eng.  Pat.,  8,196,  1889). 
t  Journ.  Soc.  Chem.  Ind.,  1882,  p.  77. 


COMMERCIAL    GLYCERINES.  515 

set  Jfree,  separable  by  filtration.  By  treating  with  carbon  dioxide 
any  caustic  alkali  is  carbonated,  and  its  removal  by  salting  out 
on  evaporation  rendered  more  easy  (Versmann).  By  adding 
tannin  in  some  form  or  other,  albuminous  matters  may  be 
coagulated  and  precipitated  (Payne).  The  substitution  of 
sodium  sulphate  for  common  salt  in  the  salting  out  process  is 
said  to  facilitate  the  separation  of  saline  matters  on  evaporation, 
and  the  remaining  sodium  sulphate  finally  remaining  to  interfere 
less  with  the  purification  by  distillation,  ultimately  necessary  to 
render  the  glycerol  suitable  for  most  of  the  purposes  for  which  it 
is  employed  (Benno,  Jappe,  &  Co.)  Spent  leys  produced  when 
black  ash  liquors  are  directly  used  for  soapmaking,  contain  a 
variety  of  impurities  not  present  when  purer  caustic  soda  is  used, 
especially  that  made  by  the  ammonia  process ;  such  liquors  may 
be  considerably  purified  by  the  addition  of  soluble  copper  salts, 
whereby  sulphocyanides  and  organic  matters,  <fec.,  are  precipi- 
tated (Allen,  and  Nickels). 

A  few  years  ago  the  Michaud-Freres  process  for  saponifying 
glycerides  with  zinc  oxide  (p.  379)  instead  of  lime,  attracted 
considerable  attention,  it  being  expected  that  fatty  acids  and 
glycerol  would  be  so  readily  obtained  that  the  older  soap  boiling 
processes  would  be  superseded,  and  direct  neutralisation  processes 
(p.  451)  substituted  for  them,  whilst  almost  pure  glycerol  would 
result,  as  in  the  candlemaking  lime  autoclave  process.  As  yet, 
however,  this  result  has  not  been  brought  about  to  such  an 
extent  as  seriously  to  interfere  with  the  older  soapmaking 
processes.  A  similar  remark  applies  to  methods  based  on 
sapouification  with  ammonia  solution  under  pressure  (p.  379). 

Commercial  glycerines  often  contain  impurities  of  various 
descriptions  best  estimated  by  direct  determination.  Lime,  lead, 
magnesia,  saline  matters,  and  similar  nonvolatile  substances  are 
left  behind  on  evaporation  and  incineration,  and  may  be  examined 
in  the  ordinary  ways ;  distilled  glycerines  only  contain  minute 
amounts  of  inorganic  matter,  rarely  exceeding  0*1  to  0'2  per  cent. 
Silver  nitrate  forms  no  precipitate  or  darkening  in  colour  after 
standing  24  hours  when  added  to  glycerines  free  from  acrolein, 
formic  acid,  or  other  substances  capable  of  reducing  silver  salts, 
but  blackens  considerably  in  their  presence.*  Traces  of  chlorides 
will  not  precipitate  silver  nitrate,  silver  chloride  being  slightly 
soluble  in  glycerol ;  glycerines  from  soap  leys,  however,  give 
copious  precipitates,  as  they  usually  contain  several  per  cents,  of 
sodium  chloride.  Such  leys  often  contain  resinous  matters,  albu- 
minoids, fatty  acids,  and  other  substances  precipitable  by  basic 
lead  acetate.  Cane  sugar  and  glucose  are  sometimes  added  as 
adulterations,  easily  detected  by  the  cuprous  oxide  (Fehling's) 

*  According  to  Ritsert,  pure  glycerol  gives  neither  deposit  of  metallic 
silver,  nor  formation  of  yellow  colour,  when  mixed  with  its  own  volume  of 
ammonia  solution,  heated  to  boiling,  and  treated  with  silver  nitrate. 


516  OILS,    FATS,    WAXES,    ETC. 

test.  Glycerol  intended  for  dynamite  manufacture  should  be 
wholly  free  from  organic  impurities,  because  the  action  of  nitric 
acid  thereon  during  nitration  might  seriously  endanger  the  suc- 
cess of  the  process  and  the  stability  of  the  product.  Chlorides, 
except  in  the  merest  traces,  should  similarly  be  absent ;  whilst 
other  inorganic  matters  (lime,  &c.)  should  only  be  present  in  traces. 

Estimation  of  Glycerol  in  Watery  Solutions. — For  the 
qualitative  detection  of  glycerol  in  aqueous  solution  a  variety  of 
tests  have  been  proposed,  one  of  which  (Reichl's)  is  described  011 
p.  8.  Kohn  *  recommends  the  following  method  : — The  liquid 
to  be  examined  is  evaporated  with  acid  potassium  sulphate  and 
the  residue  heated  in  a  retort ;  if  glycerol  is  present,  acrolein  is 
formed,  so  that  the  distillate  gives  a  red  coloration  on  treatment 
with  a  solution  of  rosaniline  that  has  been  just  decolorised  by 
sulphurous  acid. 

Several  processes  have  also  been  proposed  for  the  quantitative 
determination  of  glycerol,  some  of  which  are  only  suitable  under 
particular  conditions:  thus  in  the  case  of  distilled  glycerines  of 
considerable  or  tolerable  purity  where  organic  matters  are  absent 
and  inorganic  constituents  and  water  are  the  only  impurities  (no 
adulteration  with  glucose  or  other  sugar,  &c.,  being  present),  the 
amount  of  glycerol  may  be  conveniently  ascertained  by  oxidation 
with  potassium  dichromate  and  sulphuric  acid,  either  collecting 
the  carbon  dioxide  formed,  or  determining  the  dichromate  reduced 
by  using  a  known  quantity  and  back-titrating  with  a  standard 
iron  solution.!  Another  method  applicable  under  such  condi- 
tions is  the  "acetin  process"  of  Benedikt  (p.  186),  where  the 
substance  is  heated  with  excess  of  acetic  anhydride  and  anhy- 
drous sodium  acetate,  and  the  weight  of  potash  (KOH  =  56'1) 
determined,  neutralised  by  the  acetic  acid  formed  on  saponiti- 
cation  of  the  triacetin  produced  (after  destroying  the  excess 
of  acetic  anhydride  by  boiling  with  water).  J  92  parts  of  glycerol 
correspond  with  3  x  56*1  =  168'3  parts  of  KOH  thus  neutralised. 
Weak  glycerol  solutions  must  be  evaporated  down  until  at  least 
50  per  cent,  of  glycerol  is  present  in  the  fluid. 

Two  physical  methods  are  applicable  in  the  case  of  glycerol 
solutions  where  no  appreciable  amount  of  interfering  impurity 
is  present,  so  that  practically  only  glycerol  and  water  are  con- 
tained ;  these  are  based  respectively  on  the  determination  of 
the  specific  gravity  at  15°,  and  of  the  refractive  index  at  the 
same  temperature. 

Skalweit  gives  the  following  table  §  for  the  purpose  of  exam- 
ining glycerol  solutions  in  these  ways :  older  tables  have  also 

*  Journ.  Soc.  Chem.  Ind.,  1890,  p.  148. 

tFor  comparative  results  of  various  modes  of  testing  commercial  gly- 
cerines, vide  0.  Hehner,  Journ.  Soc.  Clvm.  Ind.,  1889,  p.  4. 

J  According  to  Hehner  (loc.  cit. )  the  liquid  must  vot  be  boiled,  as  the  tri- 
acetin rapidly  hydrolyses.  §  Repert.  Analyt.  Chemie,  v.,  18. 


SPECIFIC   GRAVITY   OF   GLYCEROL   SOLUTIONS. 


517 


been  given  by  Strohmer*  and  Lenz,  f  reproduced  by  Benedikt.  J 
Hehner  (loc.  cit.  supra}  considers  Lsnz's  table  accurate,  and 
Richmond  has  recalculated  it  to  15°-50. 

SPECIFIC  GRAVITY  AT  15°"5  (Lenz,  recalculated  by  Richmond'). 


Percentage  of 
Glycerul. 

Specific  Gravity  at 
15°  -5.      ' 

Percentage  of 
Glycerol. 

Specific  Gravity  at 
15°-5. 

100 

1-2674 

87 

1-2327 

99 

1-2647 

86 

1  -2301 

98 

1-2620 

85 

1-2274 

97 

1-2594 

84 

1-2248 

98 

1-2567 

83 

1-2222 

95 

1-2540] 

82 

1-2196 

94 

1-2513 

81 

1-2169 

93 

1-2486 

80 

1-2143 

92 

1  -2460 

79 

1-2117 

91 

1  -2433  ] 

78 

1-2090 

90 

1-2406 

77 

1-2064 

89 

1-2380 

76 

1-2037 

88 

1-2353 

75 

1-2011 

SPECIFIC  GRAVITY  AND  REFRACTIVE  INDEX  OF  GLYCEROL 
SOLUTIONS  (Skalweit). 


Percentage 
of 
Glycerol. 

Specific 
Gravity  at 
15°  0. 

Refractive 
Index  for  D  at 
16°  0. 

Percentage 
of 
Glycerol 

Specific 
Gravity  at 
15°  0. 

Refractive 
Index  for  D  at 
15°  0. 

100 

1  -2650 

1-4742 

50 

•1290 

•3996 

98 

1  -2600 

1-4712 

48 

•1236 

•3966 

96 

1  -2550 

1-4684 

46 

•1182 

•3938 

94 

1  -2499 

1  -4655 

44 

•1128 

•3910 

92 

•2447 

1  -4625 

42 

•1074 

•3882 

90 

•2395 

1  -4595 

40 

•1020 

•3854 

88 

-2341 

1-4565 

38 

•0966 

•3827 

86 

•2287 

1  -4535 

36 

1-0912 

•3799 

84 

•2233 

1  -4505 

34 

1-0858 

•3771 

82 

•2179 

1-4475 

32 

1-0804 

•3743 

80 

•2125 

1-4444 

30 

1-0750 

•3715 

78 

•2071 

1-4414 

28 

1-0698 

•3687 

76 

•2017 

1-4384 

26 

1-0646 

•3660 

74 

•1963 

1-4354 

24 

1-0594 

•3633 

72 

•1909 

1-4324 

22 

1-0542 

•3607 

70 

•1855 

1  -4295 

20 

1  -0490 

•3581 

68 

1-1799 

1-4265 

18 

1  -0440 

•3555 

66 

1-1743 

1-4235 

16 

1-0390 

•3529 

64 

M686 

1-4205 

14 

1  -0340 

•3503 

62 

1-1628 

1-4175 

12 

1-0290 

•3477 

60 

1-1570 

1-4144 

10 

1-0240 

•3452 

58 

1-1514 

1-4104 

8 

1-0192 

•3426 

56 

1-1458 

1-4084 

6 

1-0144 

•3402 

54 

1-1402 

1  -4054 

4 

1-0096 

•3378 

52 

1-1346 

1-4024 

2 

1-0048 

•3354 

*  Monatsh.  ,/iir  Chemie,  v.,  61.         t  Zeitsch.  f.  Analyt.  Chemie,  xix.,  302 
J  Analyse  der  Fette,  2nd  edition,  p.  256,  et  seq. 


518 


OILS,    FATS,    WAXES,    ETC. 


Another  physical  process  is  also  available  for  such  fluids  as 
the  comparatively  pure  solutions  of  glycerol  obtained  kin  the 


Fig.  144. 


course  of  preparing  candle  materials  (autoclave  "  sweet  waters  "), 
or   for  distilled   glycerines   retaining   only   small    quantities  of 


519 

impurities  ;  this  is  based  on  the  differences  in  the  tension  of 
the  vapour  emitted  by  glycerol  solutions  of  various  degrees  of 
concentration.  Gerlach's  vaporimeter  for  this  purpose  is  repre- 
sented by  Fig.  144.  A  B  is  a  hollow  metal  cylinder  with  dished 
bottom  for  heating  ;  G  a  glass  cylinder  fitting  therein  and  made 
watertight  by  the  indiarubber  ring,  H.  To  use  the  instrument, 
G  is  disconnected  and  the  whole  turned  upside-down  ;  the  reser- 
voir, F,  filled  with  mercury  and  a  little  of  the  fluid  to  be  examined, 
is  then  connected  by  a  bit  of  rubber  tubing  to  the  end  of  the 
pressure  tube,  D  D,  passing  inwards  through  the  tubulus,  C.  The 
instrument  is  then  erected,  and  filled  with  hot  water  after  fixing 
G  in  position,  the  temperature  being  then  raised  to  boiling  by 
heating  B.  The  expansion  of  the  mercury  on  heating  and  the 
further  expulsion  thereof  by  the  vapour  emitted  from  the  glycerol 
solution  fill  the  pressure  tube,  D  D,  with  mercury  up  to  a  given 
level  :  the  length  in  millimetres  of  the  level-difference  between 
the  mercury  in  the  reservoir  and  that  in  the  open  limb  of  the 
pressure  tube  (known  by  means  of  the  attached  scales)  repre- 
sents the  difference  between  the  tension  of  aqueous  vapour 
emitted  from  pure  water  (equal  to  the  existing  barometric 
pressure)  and  that  of  the  vapour  emitted  by  the  glycerol  solution: 
from  this  the  percentage  of  glycerol  is  reckoned  by  means  of  the 
table  on  next  page. 

When  organic  substances  are  absent  capable  of  forming  oxalic 
acid  under  the  influence  of  alkaline  permanganate,  moderately 
sharp  valuations  may  be  obtained  by  converting  the  glycerol 
into  oxalate  (Wanklyn  and  Fox  ;  Benedikt  and  Zsigmondy  ; 
A.  H.  Allen).  The  liquid  is  rendered  strongly  alkaline  and 
boiled  with  excess  of  permanganate ;  this  is  destroyed  by  sodium 
sulphite  or  sulphur  dioxide  and  the  liquid  filtered  and  precipi- 
tated as  calcium  oxalate. 

When  this  process  is  applied  to  the  determination  of  the 
amount  of  glycerol  furnished  on  saponification  by  a  given  oil  or 
fat,  the  preliminary  saponification  should  be  effected  by  means 
of  caustic  potash  and  pure  methylic  alcohol ;  the  solution 
obtained  by  treating  2  to  3  grammes  of  oil  is  evaporated  and 
the  residue  treated  with  hot  water  and  dilute  hydrochloric  acid  : 
a  little  solid  paraffin  wax  may  conveniently  be  added  to  help  the 
solidification  of  liquid  fatty  acids  on  cooling.  The  whole  is 
filtered  and  washed,  neutralised  with  potash  and  about  10 
grammes  more  potash  added ;  enough  5  per  cent,  potassium 
permanganate  solution  (or  the  powdered  salt)  is  then  added  to 
render  the  fluid  no  longer  green,  but  blue  or  blackish  :  the  whole 
is  then  heated  to  boiling  whereby  hydrated  manganese  dioxide 
separates,  the  liquid  becoming  red ;  aqueous  sulphurous  acid  is 
then  added  till  decolorisation  is  produced,  and  the  whole  filtered : 
the  filtrate  is  acidulated  with  acetic  acid  (whereby  any  turbidity 
due  to  passage  of  manganese  dioxide  through  the  filter  is  removed 


520 


OILS,    FATS,    WAXES,    ETC. 


by  the  action  of  the  sulphurous  acid  set  free)  and  the  oxalic  acid 
present  precipitated  by  calcium  chloride  or  acetate ;  the  calcium 
oxalate  is  ignited,  dissolved  in  excess  of  seminormal  acid  and 
back-titrated  with  seminormal  alkali,  using  methyl  orange  as 
indicator.  1  c.c.  of  normal  acid  (2  c.c.  of  seminormal)  corresponds 
with  46  milligrammes  of  glycerine. 


Percentage  o 
Glycerol. 

Specific  Gravity  of  Solution. 

Boiling  Poin 
of  Solution. 

Tension  of 
Vapour 
emitted 
at  100°. 

Diminution  in 
Tensiou 
Compared  wit 
Water  giving 
760  Millimetres. 

At  15°. 
Water  at 
15°  =  1. 

At  20°. 
Water  at 
20°  =  1. 

Degrees  C. 

100 

1-2653 

1-2620 

290 

64 

696 

99 

1  -2628 

1-2594 

239 

87 

673 

98 

1  -2602 

1  -2568 

208 

107 

653 

97 

1-2577 

1  -2542 

188 

126 

634 

96 

1  -2552 

1  -2516 

175 

144 

616 

95 

1  -2526 

1-2490 

164 

162 

698 

94 

1-2501 

1-2464 

156 

180 

580 

93 

1  -2476 

1-2438 

150 

198 

562 

92 

1  -2451 

1-2412 

145 

215 

545 

91 

1  -2425 

1-2386 

141 

231 

529 

90 

1  -2400 

1  -2360 

138 

247 

513 

89 

1  -2373 

1  -2333 

135 

263 

497 

88 

1  -2346 

1-2306 

132-5 

279 

481 

87 

1-2319 

1-2279 

130-5 

295 

465 

86 

1-2292 

1  2252 

129 

311 

449 

85 

1-2265 

1-2225 

127-5 

326 

434 

84 

1-2238 

1-2198 

126 

340 

420 

83 

1-2211 

1-2171 

124-5 

355 

405 

82 

1-2184 

1-2144 

123 

370 

390 

81 

1-2157 

1-2117 

122 

384 

376 

80 

1  2130 

1-2090 

121 

396 

364 

79 

1-2102 

1  -2063 

120 

408 

352 

78 

1  -2074 

1-2036 

119-0 

419 

341 

77 

1  -2046 

1-2009 

118-2 

430 

330 

76 

1-2018 

1-1982 

117-4 

440 

320 

75 

1-1990 

1-1955 

116-7 

450 

310 

74 

1-1962 

1-1928 

116 

460 

300 

73 

1-1934 

1-1901 

1154 

470 

290 

72 

M906 

T1874 

114-8 

480 

280 

71 

1-1878 

1-1847 

114-2 

489 

271 

70 

1-1850 

1-1820 

113-6 

496 

264 

65 

1-1710 

1-1685 

111-3 

533 

227 

60 

1-1570 

1-1550 

109 

565 

195 

55 

1-1430 

1-1415 

107-5 

593 

167 

50 

1-1290 

1-1280 

106 

618 

142 

45 

1-1155 

1-1145 

105 

639 

121 

40 

1-1020 

1-1010 

104 

657 

103 

35 

1  -0885 

1  -0875 

103-4 

675 

85 

30 

1  -0750 

1-0740 

102-8 

690 

70 

25 

1-0620 

1-0610 

1023 

704 

56 

20 

1  -0490 

1-0480 

101-8 

717 

43 

10 

1  -0245 

1-0235 

100-9 

740 

20 

0 

1-0000 

1-0000 

100-0 

760 

0 

OXALATE    PROCESS   FOR   VALUATION   OF    GLYCERINES. 


521 


The  quantity  of  glycerol  thus  found  is  close  to,  but  generally 
a  little  below,  that  deduced  from  the  saponification  equivalent 
of  the  substance  on  the  assumption  that  only  triglycerides  are 
present.*  In  the  case  of  oxidised  drying  oils,  however,  a  notable 
excess  is  observed,  doubtless  on  account  of  the  formation  of  other 
products  yielding  oxalic  acid  by  oxidation.  Thus  Benedikt  and 
Zsigmondy  obtained  the  following  values  : — 


Name  of  Oil,  &c. 

Glycerol  ca^ulated  from 
the  Saponification 
Equivalent. 

Glycerol  found  by  Oxalic 
Acid  Process. 

Olive  oil,             .... 

10-49  to  11-10 

10-15  to  10-38 

Coker  butter,  . 
Tallow  
Cows'  butter  fat, 
Linseed  oil, 
Skins  from  boiled  linseed  oil, 

14-76  to  14-83 
10-72 
12-51 
10-24  to  10-66 

13-3    to  14-5 
9-94  to  10  21 
11-59 
9-45  to    9-97 
15-5  (Allen) 

The  following  table  exhibits  the  amounts  of  glycerol  theo- 
retically obtainable  from  100  parts  of  the  triglycerides  of  the 
respective  acids  named ;  the  last  column  indicates  the  amount 
of  fatty  acid  simultaneously  produced  : — 


Glyceride  of 

Formula  of  Acid. 

Percentage  of 
Glycerol. 

Percentage  of 
Fatty  Acid. 

Butyric  acid, 

^14^8^2 

30-5 

87-41 

Laurie 

CifHgjOa 

14-4 

94-04 

Myristic 

Ci4H28O2 

127 

94-47 

Palmitic 

Ci6H3202 

11-42 

95-28 

Steario 

Ci8H3602 

10-34 

95-73 

Oleic 

V\$HS402 

10-41 

95-70 

Ricinoleic 

CisHsjOs 

9-98 

95-92 

Lmolic 

Ci8H32O2 

10-48 

95-67 

In  the  case  of  the  higher  acids  the  sum  of  the  glycerol  and 
fatty  acids  is  approximately  constant  —  viz.,  106  to  107  per  100  of 
glyceride  used. 

C.  Mangold  f  modifies  the  oxalic  acid  process  by  dissolving 
0'4  gramme  of  the  glycerine  to  be  tested  in  300  c.c.  of  water 
containing  10  grammes  caustic  potash,  and  adding  55  c.c.  of  a 
5  per  cent,  solution  of  potassium  permanganate.  After  standing 
half  an  hour  hydrogen  peroxide  solution  is  added  until  all 
manganese  is  precipitated.  A  known  fraction  of  the  total  fluid 

*  If  E  is  the  mean  saponification  equivalent  of  a  mixture  of  triglycerides, 
3E  milligrammes  of  the  mixture  theoretically  yield  92  of  glycerol  = 


x  100,  or 


per  cent. 


t  Zeits.  angew.  Chem.,  1891,  p.  400. 


522  OILS,    FATS,    WAXES,    ETC. 

is  filtered  off,  boiled  for  half  an  hour  to  destroy  excess  of 
hydrogen  peroxide,  acidulated  with  sulphuric  acid  after  cooling, 
and  titrated  with  permanganate  so  as  to  determine  the  oxalic 
.acid  produced. 

David  recommends  the  following  process  for  determining  the 
amount  of  glycerol  formed  on  saponifi cation.  100  grammes  of 
fat  are  heated  with  65  of  crystallised  barium  hydrate,  and  80  c.c. 
of  95  per  cent,  alcohol  added  with  agitation.  The  nearly  solid 
mass  is  boiled  with  500  c.c.  of  water  and  allowed  to  settle  ;  the 
residue  left  on  pouring  off  the  supernatant  fluid  is  washed  twice 
by  decantatioii,  and  the  total  fluid  evaporated  to  half  its  bulk 
with  sulphuric  acid,  the  surplus  being  removed  by  barium  car- 
bonate. Finally  the  filtered  fluid  is  evaporated  to  50  c.c.  and 
examined  either  as  to  its  refractive  power  or  as  to  its  specific 
gravity,  the  amount  of  glycerol  being  deducible  by  means  of  the 
table  given  on  p.  517. 

According  to  Hehner  (loc.  cit.  supra)  the  bichromate  process 
(p.  516)  gives  sufficiently  accurate  results  for  practical  purposes 
with  fats  and  soaps  when  thus  carried  out ;  the  fat  is  saponified 
with  alcoholic  potash  (about  3  grammes  being  used)  and  diluted 
to  about  200  c.c.  ;  the  fatty  acids  are  separated  by  means  of 
dilute  sulphuric  acid  and  filtered  oft';  the  filtrate  is  boiled  down 
to  half  its  bulk  and  treated  with  sulphuric  acid  and  dichromate; 
Obviously  if  any  traces  of  alcohol  are  left  in  the  fluid,  or  if 
soluble  acids  or  other  organic  matters  capable  of  reducing  di- 
chromate are  present,  the  results  will  come  out  too  high.  Oper- 
ating in  this  way  Hehner  obtained  the  following  percentages  of 
glycerol  : — 

Olive  oil,    ....         10-20  per  cent. 
Cod  liver  oil,          .  .  .  9'87         ,, 

Linseed  oil,  .  .  .          10 '24         ,, 

Margarine,  .  .  .         10 '01         ,, 

Butter  fat,  .  .       11 -96  to  12 -4 

When  chlorides  or  aldehydic  matters  are  present  (e.g.,  acrolein 
in  distilled  glycerines)  the  glycerol  solution  is  first  treated  with 
silver  oxide,  being  slightly  diluted  and  warmed  therewith  in  a 
flask  ;  basic  lead  acetate  is  then  added  in  slight  excess,  the  fluid 
made  up  to  a  known  bulk,  and  an  aliquot  part  filtered  off  through 
a  dry  filter  and  treated  with  dichromate. 

Glycerol  in  Soap  Leys.  —  On  account  of  the  organic  im- 
purities present  in  soap  leys  along  with  large  amounts  of  in- 
organic salts,  the  above  methods,  as  a  rule,  are  not  directly 
available  for  the  estimation  of  glycerol  in  such  liquors.  By 
evaporation  these  may  be  concentrated  without  material  loss 
of  glycerol  at  first,  although  subsequently  a  perceptible  amount 
is  carried  away  with  the  escaping  water  vapour  as  the  liquors 
become  highly  concentrated.  When  the  evaporation  is  carried 


GLYCEROL  IN  SOAP  LEYS.  523 

nearly  to  dryness  a  residue  is  obtained  from  which  nearly 
absolute  alcohol  dissolves  out  glycerol  along  with  more  or  less 
inorganic  matter  ;  a  rough  estimate  of  the  glycerol  present  is 
obtainable  by  evaporating  the  alcoholic  solution  to  dryness 
and  weighing,  and  then  gently  incinerating  so  as  to  burn  off 
organic  matter,  the  weight  of  ash  left  being  deducted  from  that 
of  the  total  residue.  If,  however,  other  organic  matters  soluble 
in  alcohol  be  present,  obviously  they  would  thus  be  reckoned 
as  glycerol  ;  in  some  cases  a  partial  purification  of  the  glycerol 
may  be  brought  about  by  again  evaporating  the  alcoholic  extract, 
treating  the  residue  with  a  small  quantity  of  absolute  alcohol, 
and  then  adding  one  and  a-half  times  the  volume  of  ether ; 
glycerol  is  kept  in  solution,  but  some  of  the  other  organic  matters 
are  usually  precipitated,  so  that  a  partial  purification  is  brought 
about.  In  other  cases  the  crude  glycerol  may  be  purified  by 
treatment  with  neutral  or  basic  lead  acetate  to  precipitate 
colouring  matters,  &c.  When  rosin  is  present  in  the  liquors 
they  may  be  conveniently  purified  by  evaporating  down  after 
neutralising  with  dilute  sulphuric  and  adding  a  little  milk  of 
lime  (whereby  most  of  the  rosin  is  converted  into  insoluble 
lime  salt)  and  filtering  ;  the  residue  is  treated  with  a  mixture  of 
three  volumes  absolute  alcohol  and  one  of  pure  ether,  the  dis- 
solved matter  weighed  (after  expulsion  of  the  solvent)  and 
corrected  for  ash  left  on  incineration  (Fleming"). 

Another  process  (Muter's)*  consists  in  heating  the  crude 
glycerol  liquors  with  basic  lead  acetate  to  remove  certain  kinds 
of  organic  matters  that  would  interfere  with  the  subsequent 
part  of  the  test,  filtering  and  removing  the  lead  by  sulphuretted 
hydrogen,  and  then  treating  with  caustic  soda  or  potash,  and 
dropping  in  copper  sulphate  solution  with  continuous  agitation 
until  copper  hydroxide  remains  permanently  undissolved  ;  the 
quantity  of  copper  contained  in  the  blue  solution  is  about  pro- 
portionate to  the  amount  of  glycerol  present  (under  certain  con- 
ditions— vide  infra),  so  that  by  determining  the  dissolved  copper 
the  glycerol  is  known.  For  this  purpose  Muter  employs  a 
standard  solution  of  potassium  cyanide,  for  which  the  author 
has  substituted  a  colorimetric  process  based  011  comparison  of 
the  hue  of  the  tinted  fluid  (filtered)  with  that  of  a  known  relative 
thickness  of  copper  solution  containing  a  known  amount  of 
copper  also  dissolved  in  glycerol  solution  under  the  same  con- 
ditions.! 

Unless  the  proportion  of  caustic  alkali  present  is  uniform,  a 
measurable  difference  in  the  solvent  power  of  glycerol  for  copper 
hydroxide  is  noticeable,  as  the  amount  of  alkali  varies  (Puls) ; 
so  that  when  a  cyanide  solution  is  used  it  should  be  standardised 

*  Analyst,  1881,  p.  41. 

t  Alder  Wright,  "Cantor  Lectures,"  Society  of  Arts  Journal,  1885, 
xxxiii.,  p.  1123. 


524  OILS,    FATS,    WAXES,    ETC. 

by  means  of  a  known  glycerol  copper  solution  prepared  side  by 
side  with  the  substance  examined  in  exactly  the  same  way. 

Crude  glycerol  solution,  purified  by  basic  lead  acetate,  usually 
retains  but  little  of  any  organic  matters  of  an  alcoholiform  or 
liydroxylated  character,  so  that  the  acetin  method  (supra]  can 
generally  be  applied  without  serious  error  to  the  residue  left  on 
evaporation  and  extraction  with  alcohol.  This,  however,  is  not 
so  certainly  the  case  as  regards  the  oxalate  method,  there  being 
a  possibility  of  obtaining  oxalate  by  the  oxidation  of  organic 
matters  other  than  glycerol ;  whilst  the  dichromate  process  is 
usually  inapplicable,  organic  impurities  being  generally  still  left 
which  readily  reduce  dichromate. 

A  method  sometimes  employed  is  to  heat  a  quantity  of  crude 
glycerine,  representing  about  2  grammes  of  glycerol,  with  40 
grammes  of  litharge  to  about  130°,  taking  care  that  no  carbonic 
acid  gets  access  to  the  mass  ;  when  the  weight  becomes  constant 
the  whole  is  similarly  heated  to  160°,  at  which  temperature  the 
glycerol  is  volatilised  excepting  that  a  molecule  of  water  remains 
behind  combined  with  the  lead  oxide,  so  that  the  loss  of  weight 

74 
is  —  times  the  glycerol  present;   hence  the  loss  of  weight  at 

92 
160°  multiplied  by  —  =  1*243  represents  the  glycerol  present. 

"With  glycerol  containing  resinous  matter  it  is  impracticable  to 
expel  all  the  glycerol  at  160°;  whilst  if  chlorides  or  sulphates  of 
alkali  metals  are  present  these  react  on  the  lead  oxide  forming 
hydroxides  which  readily  absorb  carbonic  acid  (Hehner). 


525 


INDEX. 


ABB£,  refractive  index,  51. 

Abel,      flashing     point      apparatus, 

126. 
Absolute  measure,  determination  of 

viscosity  in,  107. 
Absorption  of  oxygen  by  fatty  acids, 

by  oils,  42,  125,  129- 

137,  318,  341. 

,,  ,,     during  cod  liver  oil 

extraction,  preven- 
tion of,  248. 

,,      quickened    by   boil- 
ing, 129,  313. 

,,  ,,      test   for   lubricating 

oils,  134,  330. 
See      also      Oils 
(blown),  Oils  (dry- 
ing), Gumming. 
,,  spectrum,  50. 

Acajou — see  Oil  (cashewnut). 
Accumulators — see  Hydraulic  presses. 
Acetic   anhydride,    action    on   acids 
from     Turkey     red    oils, 
335. 
,,  action  on  alcohols,  glycerol, 

&c.,  8,  13,  186,  191. 
,,  action   on    cholesterol    and 

allied  bodies,  17,  191. 
,,  action      on      hydroxylated 
acids,  35,  37,  41,  186-191. 
„  action     on      non- hydroxy- 
lated acids,  189-191. 
,,  action  on  cenanthol,  25. 
Acetyl  acid  number  (acetyl  saponiti- 

cation  number),  187. 
Acetyl    number,    titration  ;     acetyl 

number,  distillation,  198. 
Acetylation  test  (acetyl  test,  acetyl 
number),     17,     43, 
121,  129,  157,  341. 
,,  ,,    process   of   working, 

186-191. 

,,  ,,    process  of   working, 

Lewkowitsch's  dis- 
tillation modifica- 
tion, 190,  198. 


Acetylation  test,  use  of,  in  analysis  of 
glycerine,  8, 186, 
516. 

,,         „  ,,  in      analysis     of 

lubricants,  329. 

„         ,,  „  in     analysis     of 

Turkey  red  oils, 
335. 

„         „  ,,  in     analysis     of 

Yor  ks  hire 
grease,  273. 
Acid,  acetic,  20,  288. 

,,      as     solvent     (Valenta's 

test),  55-57,  347,  349. 
„      formed  from  oleic  acid 

24,  28,  30,  387. 
acetyl  oxyoleic,  189. 

,,      oxystearic,  186. 
acrylic,  25,  27. 
aldepalmitic,  24,  25. 
angelic,  25. 
anhydrodioxystearic,  42,  46. 

,,     possibly  formed  in 
blown  oils,  319. 
,,      arachic  (arachidic,  butic),  21. 
,,  ,,       separation  from   other 

fatty  acids,  112. 
,,      azelaic,  34,  35,  36. 
,,      benic  (behenic,  benistearic),21. 
,,      benolic  (behenolic),  31,  32,  45. 
,,      benomargaric,  21,  22. 
,,      benoxylic,  45. 
,,      benzole,  19,  32. 
,,      bcnzoleic,  32. 
,,      benzoyl  oxymyristic,  37. 
„      brassic  (brassaidic),  28,  29,  44, 

129. 

,,      bromohypogseic,  42. 
,,      bromoleic,  28,  41. 
,,      bromomyristic,  38. 
,,      bromostearic,  30. 
,,      butic — see  Acid  (arachic). 
,,      butyric,  20,  288. 
,,      camphic,  32. 
,,      campholenic,  32. 
,,      caproic—  see  Acid  (hexoic). 
„      capric— see  Acid  (decoic). 
,,      caprylic — see  Acid  (octoic). 
carbolic — see  Phenol. 


526 


INDEX. 


Acid,  carnaubic,  21. 

,,  cerotic,  21,  190,  358. 
„  ,,    formation,  test  of  adulter- 

ation of  beeswax,  359. 

,,  cetic,  21,  22. 

,,  chloriodostearic,  177. 

,,  chlorocrotonic,  31,  32. 

,,  chloropropiolic,  32. 

,,  cimioic,  25. 

,,  cimiamic,  19. 

„  cocinic,  20,  22. 

,,  crotonic,  25,  288. 

,,  crotonoleic,  288. 

,,  damaluric,  24,  25. 

,,  daturic,  21. 

,,  decenoic,  25. 

,,  decoic  (capric),  20,  190. 

,,  diacetyloxysteario,  190. 

,,  diallyl  acetic,  32. 

,,  dibromopropionic,  27. 

,,  dibromostearic,  31,  41,  176. 

,,  dibromoxystearic,  176. 

,,  dichloracylic,  32. 

,,  diiodostearic,  26. 

,,  dioxybenic,  28,  29,  44,  129. 

,,  dioxybenolic,  45. 

,,  dioxyheiidecoic,  44. 

,,  dioxypalmitic,  42,  44,  336. 

„  dioxystearic,    28,    30,    41-45, 

128,  190. 

,,  diricinoleic,  146. 

,,  diricinoleosulphuric,  146,  333. 

,,  dodecenoic,  25. 

,,  dodecoic — see  Acid  (lauric). 

,,  doeglic,  25. 

,,  ,,       existence  doubted.  24. 

,,  elceomargaric,  32. 

,,  eloeostearic,  32. 

„  elaidic,  28,  29,  43,  44. 

,,  enneadecoic,  21. 

,,  ennenoic,  25. 

,,  eiinoic,  20,  36. 

„  erucic,  25,  28,  29,  32,  44,  129, 

180. 
,,  ,,       characteristic  of    rape 

class,  284. 
,,  ,,       oxidation  products  of, 

28,  29,  44,  129. 

,,  formic,  20,  288. 

,,  geoceric,  21,  22. 

,,  geranic,  15. 

,,  glycerosulphuric,  144. 

, ,  hendecenoic,  20,  25,  32,  40,  44. 

,,  hendecinoic  (hendecolic,  unde- 

colic),  31,  32. 

,,  hen  decoic,  20. 

,,  hendecolic,  31,  32. 

,,  heptadecenoic,  25. 

,,  heptoic  (cenanthic),20,40,41,146 


Acid,  hexabromostearic,  176. 
,,      hexacetyllinusic,  37. 
, ,      hexoic  (caproic),  20,  288. 
,,      hexoxacetylstearic,  37. 
,,      hexoxystearic,    19,  37,  43,  44, 

128,  135. 

,,      hyaenic,  21,  22. 
,,      hydrobeiizoic,  32. 
,,      hydrochloric-see  Hydrochloric 

acid. 

„      hypogseic,  25,  44,  180. 
,,  ,,  doubt  as  to  existence 

of,  24,  111. 

,,      iodopropionic,  27. 
,,      iodostearic,  30,  38. 
,,      isobutyric,  20. 
,,      isodioxybenic,  29. 
, ,      isodioxy  stearic — .see  Isomerides 

(dioxystearic  acid). 
,,      isohexoic,  20. 
,,      isohexoxystearic  —  see    Acid 

(isolinusic). 

, ,      isoleic,  25,  29,  38,  43,  44. 
,,  ,,  contained  in  distilled  cot- 

ton seed  stearine,  305. 
,,  ,,  in  candle   stearine,    262, 

375,  380. 

,,  ,,  formed   from   zinc    chlo- 

ride   and    oleic    acid, 
143,  262,  380. 

,,  ,,  formed    during    distilla- 

tion, 262,  380. 

„      isolinolenic.  37,  43,  128,  135. 
,,      isolinusic,  37,  43,  128,  135. 
,,      isoricinoleic,  41. 
,,      isotrioxystearic,  40,  43,  44. 
,,      isovaleric,  20. 
,,      isoxy stearic — see  Isomerides 

(oxystearic  acid). 
,,      lauric,  20,  71-74,  190,  288. 
,,      lignoceric,  21. 
,,      linoleic,  33,  134. 
,,      linolenic,  35,  36,  43,  44,  128, 

135,  176,  180. 

,,      linolic,  30-33,  90,  176,  180. 
,,  ,,     not  contained  in  animal 

oils,  291. 

,,  ,,     oxidationproductsof,19, 

34,  35,  43-45,  128-137. 
„      linusic,  19,  37,  43,  44,  128,  135. 
„      margaric,  21,  22,  309. 
„  „          artificial,  21,  309. 

„      medullic,  21,  22. 
„      melissic,  13,  21,  358. 
,,      methyl     crotonic  —  see    Acid 

(tiglic). 

,,      moringic,  24,  25. 
,,      myristic,  20,  31,32,  71-73,  113, 

288. 


INDEX. 


527 


Acid,  myristolic,  31,  32. 
,,      nitrous,  test  with — see  Elaidin 

reaction. 

, ,      nitric,  test  with — -sec  Nitric  acid 
,,      octenoic,  25. 
,,      octoic,  20. 

,,      oenanthic — see  Acid  (heptoic). 
„      oleic,  25,  38,  68,  75,  90-92,  113. 
,,         ,,     action    of     acetic    anhy- 
dride on,  190. 
,,         ,,        ,,  of  bromine  and  iodine 

on,  27,  176,  180. 
,,          ,,        ,,  of   fused   potash  on, 

24,  28,  30,  387. 

,,         ,,        „  of    nitrous    acid    on 

(elaidin  reaction),  28. 

,,         ,,        ,,  of  sulphuric  acid  on, 

27,  145,  149. 
,,         ,,        ,,  of    sulphur   chloride 

on,  155,  156. 
,,         ,,        ,,  of   zinc   chloride  on, 

39,  142. 
,,         ,,      amount  in  candle  stear- 

ine,  375-377. 
,,         ,,      conversion   into    stearic 

acid,  26,  386,  387. 
,,         ,,      determination  of  ( Muter 's 

process),  376. 
,,         ,,      oxidation    products    of, 

10,  28,  43-45,  128. 
,,         ,,      separation    from     other 

acids,  112,  376. 

„         ,,      soap — see,  Soapmaking. 
,,         ,,      yield  from  ox  fat,  311. 

See  also  Red  oils. 
,,      oleo-oxystearic,  330,  331. 
oleo-stearic,  331. 
orthopropionic,  12. 
,,      oxybenzoic— see  Acid  (sali- 
cylic). 

,,      oxyhypogaeic,  41,  43. 
„      oxylinoleic,  125,  134. 
,,      oxymyristic,  37,  38. 
,,      oxy oleic,  41,  42,  43,  332. 
, ,  , ,  contained  in  de"gras,  336. 

,,  formed  in  blowing  oils, 

319. 

,,      oxypalmitic,  38. 
„      oxystearic,  25,  27,  38,  39,  43, 

143-145,  330,  384. 
„      oxystearosulphuric,  27,  29,  38, 

144,  330. 

,,      palmitic,  21,  44,  72,  74,  91. 
., ,  , ,         action  of  acetic  anhy- 

dride on,  190. 
.,,  ,,         artificial,     manufac- 

ture of,  387. 
.,,  ,,         formation  from  cety- 

lic  alcohol,  13. 


Acid,  palmitic,  formation  from  oleic, 
isoleic,  and  elaidic 
acids,  30  —  see  also 
Acid,  oleic,  action  of 
potash  on. 
,,  ,,  mixed  with  stearic — see 

Candle  stearine. 
, ,  , ,    occurrence  in  arachis  oil 

denied,  111. 
,,  ,,    present  in  spermaceti  of 

low  grade,  361. 
,,  ,,    separation     from    other 

acids,  112,  113,376. 
,,    used  for  night  lights,  407. 
palmitolic,  31,  32,  45. 
palmitoxylic,  45. 
paraffmic,  21. 
parasorbic,  32. 

pelargonic— see  Acid  (ennoic). 
pentadecoic,  20,  21. 
pentaricinoleic,  147. 
pentoic,  20. 
pentolic,  32. 
petroleumic,  25. 
phoronic,  25. 

phosphoric,  colour  test,  151. 
physetoleic,  4,  25. 

,,       characteristic  of  train 

oils,  292. 
propiolic,  32. 
propionic.  20. 
pyroterebic,  25. 
rapic,  41,  43,  284. 
ricilinolic,  32,  36. 
ricinelaidic,  40,  43,  44. 
ricinic,  41. 

ricinoleic,  39,  40,  90,  176,  180. 
, ,  action  of  fused  potash  on, 

40. 
,,  oxidation  products  of,  19, 

40,  43,  44,  129. 
, ,  polymerised,  1 46, 1 47, 333. 
ricinoleos  ul  ph  uric,  1 45 , 332, 333. 
salicylic,  5,  19. 
sativic,  19,  34,  35,  43-45,  135. 
,,    as  characteristic  oxidation 

product,  128,  344. 
,,    formed  from  olive  oil,  344. 
,,    not  formed   from   animal 

oils,  291. 
sebacic,  40. 
sorbic,  32. 
stearic,  21,  72,  73,  88-92,  155, 

156,  190,  309. 
,,    adulterant  of  beeswax  and 

spermaceti,  359,  361. 
,,   formed  fromlinolic  acid,  34. 
,,         ,,     from  oleic  acid,  26, 
386,  387. 


528 


INDEX. 


Acid,  stearic,  formed  from  ricinoleic 

acid,  40. 

,,       ,,    formed  from  sativic  acid,  35. 
,,       ,,    separation       from       other 

acids,  112,  113,376. 
,,       ,,    yield  from  ox  fat,  311. 

See  also  Candle  stearine. 
,,      stearidic,  25,  30. 
„      stearolic,  31-33,  35,  45. 
,,      stearoxylic,  33,  36,  45. 
,,      stillistearic,  21,  22. 
,,      suberic,  36. 

,,      sulphuric— see  Sulphuric  acid. 
,,      sulphurous — see     Sulphurous 

acid. 

,,      tariric,  32,  36. 
,,      terebic,  25. 

,,      tetrabromostearic,  31,  176. 
,,      tetracetyl  sativic,  35. 
,,      tetradecenoic,  25. 
,,      tetraricinoleic,  147. 
,,      tetrolic,  31,  32. 
,,      tetroxy stearic — see  Acid  (sati- 
vic). 

,,      tetroxacetyl  stearic,  35. 
„      theobromic,  21,  22. 
„      tiglic  (methylcrotonic),  25,  288. 
,,      toluic,  19. 
„      tridecenoic,  25. 
,,      tridecoic,  20,  22. 
„      trioxy  stearic,  19,40,43,44,129. 
,,      trioxacetyl  stearic,  41. 
,,      triricinoleic,  147. 
,,      tritylic,  20. 
„      umbellulic,  20. 
,,      undecolic — see   Acid    (hende- 

colic). 
„      undecylic  —  see   Acid    (hende- 

coic). 
,,     undecylenic — see  Acid  (hende- 

cenoic). 

„      valeric,  20,  275,  288. 
Acid    number,  free — see  Acids  (free 

fatty). 
,,  ,,        total — see  Total  acid 

number. 

,,     process  (oil  refining),  259. 
,,      salts,  23. 
Acidity  of  soaps,  24,  498. 
Acids,  dibasic,  18. 

, ,     distilled  (manuf  acturingplant), 

382-384. 

,,  ,,     melting  points,  384. 

,,  fatty;  formed  by  hydrolysis  and 
saponitication,  7, 10, 
12,  114. 

„  „  „  during  systematic 
examination  of  oils, 
&c.,  124. 


Acids,  fatty;  formed  from  alcohols  by 

action  of  fused  potash,  13. 

„         ,,  from  glycerides,  yield  of, 

163. 

,,         ,,  from  soap,  172. 
,,         ,,  from  tallow,  palm  oil,  &c. ; 
valuation      by     melting 
point,  75,  76. 
,,         ,,  from    various    oils,    &c.  ; 

melting  points,  69-76. 
,,         ,,  insoluble    in    water  —  see 
Hehner  number;    Insol- 
uble acid  number. 
,,         ,,  insoluble     in     petroleum 
ether,   from  boiled   oils, 
135. 
,,         ,,  iodine     number    of  —  see 

Iodine  number. 
,,         ,,  mean  equivalent,  116, 164- 

173,  196. 

,,         ,,  mean   equivalent    is    less 
than  saponitication  equi- 
valent of   glycerides   by 
12-67,  165,  197. 
,,         ,,  melting    points     of — see 

Melting  points. 
,,         ,,  mixtures   of;    calculation 

of  composition,  172. 
,,         ,,  neutralisation       numbers 
of  —  see  Neutralisation 
number. 
,,         ,,  oxidation  during  drying, 

113. 
,,         ,,  oxidation  of,  from  drying 

oils,  136. 
,,          ,,  polymerised,  from  castor 

oil,  146. 

,,  ,,  separation  of,  as  lead 
salts,  &c.,  112,  128,  136, 
356,  376. 

,,          ,,  solid     from    tallow    and 
palm    oil,    74-76  —  see 
Candle  stearine. 
,,          ,,  soluble  in  alcohol,  23. 
,,          ,,  soluble  in  water,  23,  163, 

167-170,  195. 
,,          ,,  soluble  in  soap  analysis, 

497. 
,,          ,,  soluble  acid  number — see 

Soluble  acid  number. 
„         „  volatile,  22,  113—  see  also 

Boiling  points. 

,,         „      ,,    acid    number —  see 
Volatile  acid  number. 
,,          ,,      ,,    contained   in  York- 
shire grease,  275. 

,,  ,,  ,,  with  superheated 
steam — see  Distil- 
lation. 


INDEX. 


529 


Acids,  fatty,  volatile,  with  wet  steam, 
22, 112 — see  also  Reich  ert 
number ;  Volatile  acid 
number. 

,,  ,,  unsaturated,  in  pressed 
candle  stearine,  375. 

,,  free  fatty,  amount  present  in 
oilcakes,  115,214. 

,,  ,,  as  candle  material 

—  see  Candles, 
stearine. 

,,  ,,  determination  of 

free  acid  number, 
24,  115-119,  194, 
341. 

,,  ,,  determination  of, 

by  Burstyn's 
method,  118. 

,,  ,,  detrimental  effects 

of,  115,260,313, 
322,  356. 

,,  ,,  examination  of,  for 

detecting  adul- 
teration, 356. 

,,  ,,  formed  by  hydro- 

lysis— see  Hydro- 
lysis. 

,,  ,,  from  Turkey  red 

oils,  334,  335. 

,,  ,,          iodine  number,  180, 

184,  197,  356. 

,,  ,,          iodine  number  ex- 

ceeds that  of  gly- 
cerides  by  about 
4'5  per  cent., 

185,  197. 

,,  ,,          occurrence  in  natu- 

ral oils,  &c.,  114- 
119,  292,  355. 

,,  ,.          production    of,    in 

orease  recovery, 
271,  272. 
,,  ,,          proportion  usually 

present,  115. 

,,      mineral,  detection  of,  123,  323. 
,,  ,,    inadmissible     in    puri- 

fying lubricants,  325. 
,,  ,,    injurious      eti'ects      of, 

115,  260,  322,  325. 
,,      monobasic,  18. 
,,      polyhydroxylated  stearic,  43- 

46,  128-137. 
,,      series  of,  acetic  (stearic),  18, 

19. 

acrylic  (oleic),  18,  24. 
benzoic,  19. 
bromoleic,  28. 
cinnamic,  19. 
dichloroacetic,  31. 


Acids,  series  of,  dibromoacetic,  26,31. 
,,  ,,      diiodoacetic,  26. 

,,  ,,      dioxystearic    —    see 

Glyceric  series. 
,,  ,,      erythroglucic  (trioxy- 

stearic),  19,  43. 

,,  „      glyceric        (dioxy- 

stearic), 19,  27,43. 
,,  ,,      gly  collie  —  see     Oxy- 

acetic  series. 

,,  ,,      hexoxystearic,  19,  43. 

„  „      linolenic,  18,  36. 

,,  ,,      linolic—  see    Propiolic 

series. 
,,  ,,      oleic  —  see     Acrylic 

series. 

,,  ,,      oxyacetic        (oxy- 

stearic,      glycollic), 
19,  27,  37. 
,,  „      oxyacrylic(ricinoleic). 

19,  39. 

,,  ,,      oxy  benzoic,  19. 

,,  ,,      oxy  oleic  —  see     Oxy- 

acrylic  series. 

,,  ,,      oxystearic  —  see  Oxy- 

acetic series. 
,,  ,,      propiolic  ( linolic),  18, 

28,  30. 
,,  ,,      ricinoleic  —  see  Oxy- 

acrylic  series. 
,,  ,,      salicylic,  19. 

,,  ,,      stearic  —  see     Acetic 

series. 

,,  „      stearolic,  30,  31,  45. 

,,  ,,      stearoxylic,  33,  45. 

„  „      tetroxystearic,  19,  43. 

,,  ,,      trioxystearic  —  see 

Erythroglucic  series. 
Acrojein  (acrylic  aldehyde),  15,  25. 
,,         in  glycerine,  515. 
,,         produced  by  action  of  heat 

on  oils,  125. 

,,  ,,         dehydration     of 

glycerol,8,513. 

,,  ,,         oxidation  of  lin- 

seed oil  (lino- 
leum), 318. 
Actual  density,  incorrect  use  of  term, 

89. 

Adipose  tissues,  Mege  Mouries  pro- 
cess, 308. 

,,  rendering  of,  245-251. 

,,  use  of,  as  food,  303. 

Adulteration,  general  methods  of  de- 
tecting, 340-342— see  also 
each  oil,  &c.,  separately. 
,,       with  solid   suspended  mat- 
ters, determination,  123. 
JSsculin,  50. 

34 


530 


INDEX. 


^Etherzahl — see  Ester  number. 

Air,  bleaching  oils  by  means  of  hot, 

264. 
,,     used  in  preparing  blown  oils — 

see  Oils,  blown. 

,,  ,,         ,,  boiled  oils — see  Oils, 

drying,  boiling  of. 

,,     wax  bleaching  by  exposure  to, 

and  light, -268. 

Air  bath,  Pensky's,flashingpoint,  1 27. 
,,          Pohl's,  melting  point,  63. 
,,          specific  gravity,  80. 
Air  blast,  Dunn's  (soapboiling),-  433. 
Albuminous  matters,  determination, 

119-123. 

, ,  , ,     removal  from  crude 

glycerine,  5 14,515. 
,,  ,,     removal  from  oils, 

&c.  —  see     Oils 
(clarification). 
Alcohol,  allylic,  15,  44. 
,,        amylic,  14. 
,,        benzylic,  16. 
,,        butylic,  14. 
,,        cerylic,  14. 
,,  ,,       present  in  Yorkshire 

grease,  272. 

,,        cetylic,  4,  6,  7,  14. 
,,  ,,    action   of    acetic    anhy- 

dride on,  15,  191. 
,,  ,,    action  of  fused   potash 

on,  13. 
,,  ,,    contained    in    cetacean 

oils,  114,  116, 121. 
,,  ,,    contained  in  degras,  336. 

,,  ,,    contained  in  spermaceti 

— see  Spermaceti. 
,,  ,,    contained  in  Yorkshire 

grease,  272. 

,,    palmitic  acid  from,  13. 
cinnamic,  16. 
decylic  (decatylic),  14,  40. 
dodecylic   (dodecatylic),    14, 

114. 

ethylic,  4,  14. 
hendecylic,  14. 
heptadecylic,  14. 
heptylic,  14. 
hexadecylic,  14. 
hexylic,  14. 
isobutylic,  14,  20. 
isocerylic,  14. 
isomyricylic,  14. 
isopropylic,  14. 
methylic,  5,  14. 
myricylic,  4,  14,  21,  358. 
,,  action    of    fused 

potash  on,  13. 
nonylic,  14. 


Alcohol,  octodecylic,  14. 
,,        octylic,  5,  14. 
,,       pentadecylic,  14. 
,,        propylic,  14,  20. 
,,        sycocerylic,  16. 
,,        tetradecylic,  14. 
,,        tridecylic,  14. 

xylylic,  16. 

Alcohol,  solubility  in — see  Solubilitjr. 
Alcoholiform  products  of  saponifica- 

tion,  4-18,  121. 

Alcohols,  acetyl  numbers  of,  17. 
,,  dihydric — see  Glycols. 
,,  fermentation  —  see  Oils 

(fusel). 

,,         free  in  oils,  due  to  hydro- 
lysis, 7,  114,  116,  171. 
,,         hexhydric,  5. 
,,         higher,  contained  in  York- 
shire grease,  272. 
,,         monohydric,  4,  13. 
,,          pentahydric,  5. 
„         series  of,  acrylic  (allylic), 

13,  15,  44,  114. 
benzylic,  15,  16. 
cholesteric,  16. 
cinnamic,  13,  16. 
ethylic,     13,     14, 

114,  116. 
geranic,  15. 
phenolic,  13,  15. 
,,         tetrahydric — see  Erythrol. 
,,         trihydric — see  Glycerols. 
Aldehydes,  3,  6,  15. 

,,  hydrogenation  of,  14. 

,,  oxidation  of,  20,  25. 

Alkali,  calculated  quantity  requisite 
for  saponification — see   Cal- 
culations. 
,,      free,  in  soaps,  injurious  effects 

of — see  Soaps,  alkaline. 
Alkalies,  action  on  brominated  and 
chlorinated  acids,  28-32,  38. 
,,    effect  of  fusion  with — see  Hy- 
drogen. 

,,  effect  of  fusion  with,  on  oleic 
acid  and  isomerides 
see  —  Acid  (oleic, 
palmitic). 

,,  ,,       on  ricinoleic  acid,  40. 

,,    manufacture  of,  410. 
,,    mild  and  caustic,  409— see  Po- 
tash (caustic),  Soda  (caustic). 
,,    quantities  mutually  equivalent 

to  one  another,  425. 
, ,    use  of,  in  refining  oils,  &c. ,  260. 
,,    use  of,  in  soapmaking,  409. 
,,    vegetableand  mineral, 410 — see 
Potash,  Soda. 


INDEX. 


531 


Alkalimetrical  assay,  420. 

Alkaline  carbonates   as   saponifying 

agents,  409,  410. 
,,  ,,     causticising    of — see 

Causticising. 

,,  ,,     direct    use    in   soap- 

making,    409,    433, 
453,  460,  463. 

,,  earths,  use  in  refining,  256. 
,,  refining  processes-see  Refining. 
,,  soap,    injurious    effects  —  see 

Soap,  alkaline. 

,,  solutions,  strength  of,  418,  419. 
Alkalinity,  degrees  of— see  Degrees, 
negative,  498,  499. 
of  leys,  414-419. 

,,  ,,    corrections  for  impur- 

ities, 419. 
,,  ,,    effect  of  temperature 

on  density,  416. 

,,         of  soda,  British  trade  cus- 
tom, 420. 

Allbright  &  Clark,  spontaneous  in- 
""flammation,  132. 
Allen,  A.  H.,  beeswax,  358,  359. 
,,  bromine  reaction,  177. 

,,  distilled    cotton    seed 

stearine,  305. 

,,  glycerine  valuation,  519. 

,,  linolic  acid,  34. 

,,  Maumene's  test,  149. 

,,  melting  points,  71. 

,,  nitric  acid  test,  140. 

„  Reichert's  test,  174. 

relative  density,  89,  93. 
, ,  saponification       equiva- 

lents, 160. 

,,  soap  analysis,  494,  507. 

, ,  sugar  test  for  sesame",  346. 

,,  sulphur  in  oils,  123. 

,,  sulphuric  acid  colour  re- 

actions, 151. 

,,  test  for  arachis  oil,  344. 

,,  Valenta's  test,  56. 

„  viscosimetry,  99, 101, 104. 

,,  waggon  grease,  327. 

Allen  and  Nickels,  glycerine  extrac- 
tion, 515 
Allen  and  Thomson,  free  alcohols  in 

sperm  oil,  &c.,  171. 
,,        unsaponifiable  matters  in 
various  oils,  &c.,  257. 
Alligator  fat,  299. 
Allihn's  condenser,  239. 
Allyl  cyanide,  25. 

,,     ethers,  15,  25. 
Almonds,  sweet  and  bitter — see  Oil 

(almonds). 
Alpaca  fat,  299. 


Alum  in  lard,  307. 

,,      use  in  cleansing  rancid  tallow, 

256. 

Aluminium  oleate  used  in  thickening 
oils,  121-124,  324,  329. 
,,      soaps,  121-124,  324, 328, 329. 
Aluminoferric  cake,  aluminium  sul- 
phate,   use   in   recovering    grease, 
270. 
Amagat  and  Jean,  oleorefractometer, 

51. 

Ambreol  (ambergris),  3,  17. 
Ambiihl,  specific  gravity  vapour  bath, 

80. 

American  mineral  oils,  viscosity,  105. 
Ammonia  process  for  alkali  manufac- 
ture, 410. 
,,         saponification  process,  379, 

410,  515. 

,,         salt,    dealkalising    process 
( Alder   Wright's  )  —  see 
Wright,  Alder. 
Angelica,  25. 

Anglo-American  system  of  oil  pres- 
sing, 210,  215-218. 
Anhydrides,  fatty,  in  analysis,  371. 
,,    of  dioxystearic  acids,  42,  46. 
, ,    of  nonhy  droxy  lated  acids,  189. 
,,    of  oxystearic  acids,  30,  39. 
Animal  charcoal,  use  of,  in  decoloris- 
ing oils,  &c. ,  263,  269. 
,,         ,,    use    of,    in  deodorising 
cokernut  oil,  310. 
,,         ,,        ,,  in     purifying   gly- 
cerine, 514. 

,,         ,,        ,,  in     purifying  lan- 
olin,  339. 

,,     fats,  acids  from,  21,  25. 
,,       ,,     rendering  of,  245-251. 
Anise  camphor  (anethol),  192,  194. 
Anschtitz,  action  of  acetic  anhydride 

on  benzoic  acid,  &c.,  189. 
Anthracene,  extraction  from  anthra- 
cene oils,  230. 

,,      oils  (coarse  lubricants),  328. 
Antifriction  ingredients,  324-328. 
Aqua  regia,  colour  test,  151. 
Arachin  (arachicglyceride),  chief  con- 
stituent of  Rambutan  tallow,  296. 
Arachis  nuts,  decortication  of,  224. 
Araeometer,  77. 

,,  (Burstyn's  method),  118. 

,,  Lefebre's,  79. 

„  thermal,  82,  347. 

Archimedean    screw   (mixing    soap), 

440. 
Archbutt,  elaidin  test,  138. 

,,         free  fatty  acids  in  burning 
oils,  313. 


532 


INDEX. 


Archbutt,  Maumene's  test,  149. 
Argand  lamp,  313. 
Arnaud,  tariric  acid,  36. 
Ashes  as  detergents,  409. 
Artificial  butter — see  Margarine. 

,,         lard — see  Lard. 
Autoclave  for  soapmaking — see  Soap- 
making  (hydrated  soaps). 
,,          rock,  374. 
,,          stearine  process,  373— see 

Candle  stearine. 
Axle  grease  — see  Lubricants. 


B 


BACH,  absorption  of  oxygen,  134, 329. 

,,      melting  points,  71. 
Bagging  for  presscakes,  217. 

,,  of  semisolid  oils  to  separate 
"  stearines,"  spermaceti, 
&c.,  229,  305,  360. 

Ballantyne,    effect   of   light   on  oils, 
130-132,  149— see  also  Thomson  and 
Ballantyne. 
Balsam  of  Peru,  16. 
Tolu,  19. 
Barilla,  410,  473. 

Barium  polysulphide  (colour  test),  151. 
,,  sulphate,  adulterant  of  wax,  359. 
Barring  (soap),  437,  438,  444. 
Baths — see    Air    bath,     Hot    baths, 
Chilling     baths,     Vapour     baths, 
Water  baths,  &c. 

Bauerand  Hazura,  dry  ing  oils  136,290. 
Baynes,  Maumene's  test,  149. 
Beans,    fatty    matter   contained     in 

various  kinds  of,  241-244. 
Bears'  grease,  299. 
Beaume,  rational  scale,  86. 
Becchi's  test  for  cotton  seed  oil,  131, 

306,  346. 

Beech  wood  tar,  21. 
Beef  fat,  beef  tallow — see  Tallow. 
Beef  stearine — see  Stearine  (beef). 
Beeswax — see,  Wax  (bees). 
Beet  fusel  oils,  14. 

Bell,  J.  Carter,  lubricating  oils,  325. 
Bender,  viscosity,  106. 
Benedikt,  beeswax,  358. 

,,         density   of   glycerol    solu- 
tion, 517. 

hydrometer  scales,  85. 
iodine  numbers,  183. 
iodine   number   of   linseed 

oil,  351. 

phosphorus  in  oils,  124. 
total  acid  numbers,  160. 
use  of  acetylation  test,  129, 
516. 


Benedikt,  zinc  chloride  and  oleic  acid 

39,  142. 

Benedikt  and  Griissner,  methyl  num- 
ber, 192. 

Benedikt  and  Hazura,  nonformation 

of  sativic  acid  from  animal  oils,  291. 

Benedikt  and  Ulzer,  acetylation  test — 

see  Acetylation  test. 

,,  ,,        oxy oleic  acid,  42. 

,,  ,,       oxystearosulphuric 

acid,  145. 
Benedikt  and    Zsigmondy,  glycerine 

valuation,  519,  521. 
Bennett  and  Oibbs  (soapmaking  under 

pressure),  463. 

Benno  Jappe  &  Co.,  glycerine  extrac- 
tion, 515. 
Bensemann,  melting  points,  71- 

tubes,  62. 
Benzene,  3. 

as  solvent,  55,  23 1 ,  236,  252, 

254,  337,  339,  359. 
Benzoic  aldehyde,  3. 

„       ethers,  17. 

Benzoline — see  Petroleum  ether. 
Beyer,  plotting  machine,  448. 
Bicarbonate  formed  during  saponifi- 

cation,  410. 

Bichromate  process,  glycerol  estima- 
tion— see  Glycerine, 
manufacture  of 
(valuation). 

,,  (oil  bleaching), 264-266. 
,,  ,,  (wax   bleaching),   266, 

269. 
Biliary   constitu tents    in    liver   oils, 

292,  354. 

Bishop,  polarised  light,  50. 
Bladder  lard,  306. 
Bleaching  oils,  &c.,  50,  263-269,  358, 

364 

, ,          powder,  use  of  in  decoloris- 
ing oils,  264,  266,  267. 
Blown  oils — see  Oils  (blown). 
Blowpipe,  428,  433. 
Blubber,  extraction  of  oil  from,  247. 
Bock's  process,  384. 
Boiling  down  blubber,  &c.,  247. 

, ,      oils,  changes  occur  ring  during, 

125,  129. 

points,  acetic  acid  series,  20. 
,,       acrylic,  25,  28,  29. 
,,       alcohols,  14. 
,,       pure  triglycerides,  11. 
processes,  313-318. 
Bone  fat  (bone  grease,  bone  oil),  67, 
88-91,160,181-184,298,299. 
,,     adulteration     of  tallow    fat 
with,  355. 


INDEX. 


533 


Bone  fat,  extraction  of,  from  bones, 

251-254. 
,,     removal  of  calcium  phosphate, 

&c.,  contained  in,  256. 
Bone  tar  (bone  oil,  Dippel's  oil),  2,  5. 
Borneol,  15. 
Borith,  449. 
Bosch— see  Margarine. 
Bottlenose  whale— see  Oil  (Doegling). 
Bran  from  cotton  seeds,  304. 
Brandy  fusel  oils,  14. 
Brassica  (rape,  colza),  various  species 

of,  348. 

Braun  and  Liebreich,  lanolin,  338. 
Brez,  de,  moulded  caudles  invented 

by,  363,  395. 
Brine— see  Salting  out. 
Brink,  caoutchouc  in  lubricating  oils, 

323. 
Brin's  Oxygen  Co. ,  oil  boiling  process, 

321. 

Bromine  absorption,  26,  176-179. 
,,         reaction,    forming   propiolic 

acids,  31,  32,  45. 
Bromo  substitution   derivatives — see 

Substitution. 
Bruijn,    de,   and  von  Leent,   oleore- 

fractometer,  51-53. 
Buccia  (olive  marc),  343. 
Buisine,  beeswax,  269,  358. 
Bursty n's  method,  118. 
Butter,  animal,  174,  298. 

„  ,,          (ewes',    goats',   por- 

poises'),  Reichert 
number  of,  174. 
,,        cow's,  adulteration  of,  310. 

„       fat  of,  3,  9,  299. 
,,  ,,  ,,   acids     obtainable 

from,  20,  25,  70. 
,,  ,,  ,,  Hehner    number, 

166,  310. 
,,  ,,  ,,  iodine      number, 

181-134,  310. 
,,  ,,  ,,  melting  point,  67- 

70. 
,,  ,,  ,,  refractive  power, 

51-53. 
,,  ,,  ,,  Reichert  number, 

174,  310. 

„  ,,  ,,  saponification 

equivalent,  160, 
310. 

,,  ,,  ,,  solubility,   54-56. 

,,  ,,  ,,  specific     gravity, 

88-92. 

,,  ,,  quality  of,  303. 

,,  ,,   salt  contained  in,  123. 

,,  ,,  sweetening     rancid,    by 

washing  with  water,  261. 


Butter,  cow's,  water  contained  in,  122. 
,,      general  nature  of,  1. 
,,      mineral  (antimony,  tin),  1. 
, ,      vegetable  (vegetable  fat,  veget- 
able tallow),  2,  6,  47. 
„  ,,     class,  282,  295. 

Butters,  vegetable,  expression  oleines 

from — see  Oleines. 
?„  ,,     lesser  known,  295-298. 

Butters,  vegetable — 

Andiroba  fat — see  Oil  (carapa). 
Bassia    fat  (Illipe  butter,  Mahwa 
butter),  21,  56,  67,  87,  241,  243, 
295,  363. 
Bay  berry    fat — see  infra  Laurel 

butter. 
Borneo    tallow    (Malayan    tallow, 

Fever  nut  butter),  242,  296. 
Butter  nut  fat,  297. 
Cacao  butter,  21,  241,  295. 

,,  chemical  properties, 

160,  174,  181-184. 

,,  physical  properties, 

55,  56,  67-70,  87, 

88,  91. 

,,  theobromic   acid  in, 

21,  22. 

Carapa  fat — see  Oil  (carapa). 
Chinese  (Stillingia)  tallow,  21,  70, 

295,  363. 

,,  ,,     extraction  by  hot 

water     process, 
201. 

,,     yield  of,  242. 
Chequito  butter,  297. 
Cocculus  indicus  fat,  297. 
Coker  butter — see  Oil  (cokernut). 
Copra  butter —     ,,  ,, 

Caumou  butter — xee  Oil  (comnu). 
Dika  fat,  2,  20,  242,  295. 
Fever  nut  butter — see  supra  Borneo 

tallow. 
Fulwah  butter  (Indian  butter),  242, 

295. 
Gal  am   butter — see   infra   (Shea 

butter). 
Goa  butter  (Kokum  fat,  Mangosteen 

oil),  68,  242,  296. 

Illipe  butter — see  supra  Bassia  fat. 
Indian  (Fulwa)  butter— see   supra 

Fulwah  butter. 

Karanja  butter,  Korinje  butter 
(Ponga  butter,  Ponga  oil,  Poondi 
oil),  242,  296. 

Kokum  fat — see  supra  Goa  butter. 
Laurel  butter  (Laurel  oil,  Bayberry 
fat),  20,  56,  68,  181-184,  243,  296. 
Macaja  butter,  243,  297. 
Mafura  tallow,  243,  296. 


534: 


INDEX. 


Butters,  vegetable — 

Mahwa  butter  —  see  supra  Bassia 

fat. 
Malayan  tallow — see  supra  Borneo 

tallow. 
Malabar  (Piney)   tallow,   70,   160, 

244,  295,  363. 
Myristica  butters,  295. 
Nutmeg  butter — see  Oil  (nutmeg). 
Ochoco  fat,  297. 
Ocuba  fat,  295. 

Otoba  fat  (Otoba  wax),  243,  295. 
Palm  butter — see  Oil  (palm). 
Palm  kernel  (Palm  nut)  butter — see 

Oil  (palm  kernel). 
Para  butter  (Assai  oil),  297. 
Pekea  butter  (Piquia  fat) — see  Oil 

(piquia). 

Persea  fat— see  Oil  (alligator  pear). 
Phulwara  fat — see  Fulwah  butter. 
Pichurim  bean  fat,  20. 
Piney  tallow — see   supra  Malabar 

tallow. 
Ponga  butter— see  supra  Karanja 

butter. 

Poona  fat — see  Oil  (calabar  bean). 
Rambutan  tallow,  296. 
Sawarri  (Souari)  nut  butter,  297. 
Shea  (Galam)  butter,  2,  21,  70,  71, 

160,  242,  295. 

Sierra  Leone  butter,  244,  296. 
Soapberry  butter  (Soap  tree  fat), 

244,  297. 

Soudan  butter,  297. 
Stillingia  tallow — see  supra  Chinese 

tallow. 
Tacamahac    fat— see   Oil   (calabar 

bean). 

Tangkallak  fat,  244,  297. 
Ucubafat  (Ucuba  wax,  295. 
Virola  fat,  68,  295. 
Veppam  fat— see  Oil  (zedrach). 
Butterine  (butter  substitutes ;   arti- 
ficial butter) — see  Margarine. 
Butyrin    (butyric     triglyceride),    9, 

,,        not  contained  in  butter,  9. 


CABBAGE  palm  oil— see  Oil(arecanut). 
Cacao  butter— see  Butters,  vegetable 

(Cacao  butter). 

Cadmium  salts,  use  in  refining  oils,  263. 
Cailletet,  bromine  reaction,  177. 
,,        soap  analysis,  507,  508. 
Cake,  cold  press— see  Cold  press  cake. 

,,     filter— see  Filter  cake. 

,,     hot  press — see  Hot  press  cake. 


Cake,  separation-see  Separation  cake. 
Cakes,  linseed,  &c.—  see  Oilcakes. 

,,      moulded,  221-223. 
Calcium   chloride,  use  of,  in  grease 

recovery,  271. 

,,         sulphate,  formed  in  decom- 
position of  rock,  366. 
Calculations,  composition  of  mixtures.. 

172. 

,,  of  rock,  372. 

,,  ,,       of    separation 

cake,  &c.,  378. 

,,  respecting  alkaline  leys 

and  composition  of 
soaps,  421-426,  454- 
456,  464-466. 

Cambaceres,  bi-aided  wicks,  394. 
Camphor,  acids  from,  25,  32. 
,,        analogues,  3,  6. 
,,        Borneo,  15. 
,,        sodium,  oxidation  of,  25. 
Camp,  moulding  wheel,  398. 
Candle  polishing,  405. 
Candle  stearine,  110,  230,  393. 

,,  ,,       breaking  grain  of,  368r 

397,401. 
,,  ,,       crystallising — see 

Separation  cake. 

,,  „        manufacture,  364-388. 

,,  ,,  ,,  autoclave     lime 

process,  364, 
373-376. 

,,  ,,  ,,  conversion  of  red 

oils  into  stear- 
ine, 142,386-388. 
,,  ,,  ,,  cold    pressing  — 

see  Cold  press. 
,,  ,,  „  hot     pressing  — 

see  Hot  press. 

,,  ,,  „  hydrolysis   by 

water  under  in- 
creased pres- 
sure, 365,  385, 
386. 

,,  ,,  ,,  open    pan    lime 

process,  364-370. 

,,  ,,  ,,  rock  (lime  soaps) 

366,  371-374. 

,,  ,,  ,,  sulphuric      acid 

processes,  365, 
380-385. 

,,  ,,  ,,  unsaponified  fat, 

&c.  —  see     Un- 
saponified. 
„  „  »  yield,  368,  370- 

374. 

,,  ,,  mixed  fatty  acids  —  see 

Acids,  fatty,  mixtures 
of;  Melting  points. 


INDEX. 


535 


Candle  wicks— see  Wicks. 
Candlemaking  materials,  302,  363. 

,,  processes,  basting  wax 

tapers,  &c.,389. 
,,  „  dipping  by  hand, 

:i90,  391. 
,,  ,,  dipping  by  machine, 

391-394. 

,,  ,,  drawing  wax  tapers, 

spills,&c.,  389,407. 
,,  ,,  manipulation     re- 

quired in  moulding 
with  various   ma- 
terials, 401. 
,,  ,,  moulding  by  hand, 

395-398. 

,,  ,,  moulding  by  ma- 

chine, 398-406. 
,,  „  pouring,  388,  389. 

,,  ,,  threading       wicks, 

397,  399,  400,  406. 
,,  ,,  trimming,  389. 

,,  ,,  turnover  machine, 

405. 

Candles,  ceresin,  ozokerite,  and  par- 
affin, 363,  364,  401,  402. 
,,       composite,  364,  402. 
, ,        early  forms  of,  312,  313, 362, 

390,  391. 

,,       hollow,  402,  405. 
,,       medicated,  407. 
,,       self-fitting  butt  end,  402. 
,,        spermaceti     (sperm),     360, 

363,  402. 
,,  spiral,  402. 
,,  standard  (photometric), 

402. 

,,        stearine,  395,  401. 
„       tallow,  363,  402. 
„        tinted,  390,  401,  405. 

wax,  301,  362-364,  389. 
Caoutchouc,  use  in  lubricating  oils, 

323. 

Capillary  tubes  (m  elting  points)  ,60-63. 
,,  (friction  coefficient), 

107,  109. 

Capric  aldehyde,  14. 
Carapin,  296. 
Carbolic  acid— see  Phenol. 

„  soaps,  6,  477,  505,  506. 

,,  soaps,       valuation       of 

phenoloids  in,  506. 
Carbon  dioxide,   atmosphere  of,   for 

cod  liver  oil  extraction,  248. 
Carbon  disulphide  as  solvent,  55,  123, 
124,231-236,252, 
254,  337,  339,  343. 
,,         diluent  for  sulphur 
chloride,  155. 


Carbon  disulphide  lamp  for  disinfect- 
ing, 407. 

,,  ,,         "  sulphocarbon 

oils  "     extracted 
by,  344,  408. 

Carbon  tetrachloride  as  solvent,  55, 236 
Carbonates,  alkaline,  direct  saponifi- 
cation  by—  see  Alkaline  carbonates, 
Sodium  carbonate. 
Carnauba  wax — see  Wax  (Carnauba). 
Carriage  grease— see  Lubricants. 
Carriers  of  oxygen  (driers),  129,  264. 
Cart  grease — see  Lubricants. 
Casein  in  butter,  123. 
Cast  iron  less  corroded  than  wrought 

by  fatty  acids,  277. 
Castor  beans,  decortication  of,  224. 
Castorol  (castoreum),  17. 
Cattle  food,  303 — see  also  Oilcake. 
Caustic  soda — see  Soda,  caustic. 
Causticising  alkaline  leys,  409-414. 
,,  boiling  process,  412. 

,,  cold  process,  411. 

,,  under  pressure,  413, 

Centigrade  scale,  57-60. 
Ceresin  (cerasin),  2,  88. 

,,          ,,          detection     of,     in 

beeswax,  359. 
Cerolein,  358. 
Ceroxylin,  301. 
Cetaceans,  oil  from  blubber  of— see 

Oils  (cetacean). 

Cetyl  cyanide,  margaric  acid  from,  21. 
Cetylic  ethers,  4,  7. 
Chandlery  (candlemaking  trade),  363. 
Charcoal,   use  of,  in  clarifying   and 
decolorising    oils,    &c.,    255,    263, 
269 — see  also  Animal  charcoal. 
Charring  of  wicks — see  Wicks. 
Chateau,  colour  reactions,  142,  151. 
Chattaway's  tube,  120. 
Chemical  changes  during  boiling,  317. 
,,  ,,     during  drying  of  oils 

— see  Oils  (drying  of). 
Chevreul,  researches  on  fats,  309. 
Chevreul    and   Gay  Lussac,   candle 

material,  365. 

Chevreul-Milly  process,  365. 
Chequito,  297. 
Chilling  baths,  66,  67. 

,,  effect  on  viscosity,  106. 

Chimneys  (lamp),  313. 
China  clay  as  adulterant,  123, 355, 359. 

,,  (antifriction),  328. 

Chinese  wax— see  Wax  (Chinese). 
Chlorate,  potassium,  use  of,  in  bleach- 
ing oils,  &c.,  264,  266. 
Chloride  of  soda  for  soap  bleaching, 
267. 


536 


INDEX. 


Chlorine,  action  011  ethylene,  26. 

,,         bleaching  by  means  of,  264- 

267,  364. 
,,         gas,   test    for    fish   oils   in 

linseed  oil,  352. 

Chloroform  as  solvent,  17, 55, 231, 359. 
Chlorophyll,  49,  50. 
Chloro  substitution   derivatives — see 

Substitution. 

Cholesterol,  allied  bodies,  and  their 
ethers,  3,  6,  16,  17,259. 
,,  and  its  ethers  in  York- 

shire grease,  272-276. 
,,  determination      of,      in 

lubricants,  329. 
,,  ethers,  17. 

,,  extraction     from     oils, 

119-121. 

lanolin,  337-339. 
,,  occurs  in  de"gras,  336. 

,,  .,    liver  and  cetacean 

oils,  17,  292. 

,,  ,,     suint,  337. 

Choline  derivatives— -see  Lecithin. 
Chromate,    processes    for    bleaching 
oils,  wax,  &c. — -see   Bi- 
chromate. 

,,  reaction  with  glycerol — 

ste  Glycerol  extraction 
(valuation    by    bichro- 
mate process). 
Chrome  recovery,  265. 
Chromium  compounds  as  driers,  314. 
Cierges  (altar  candles),  389. 
Cinchol,  22. 

Claritication — nee  Oils  (clarification). 
Clarke,   oils  boiled  with  manganese 

driers,  314. 
Clark's  soap  test  for  hard  water,  485, 

508. 

Classification  of  oils,  &c.,  according 
to  chemical  com- 
position, 5. 

,,  ,,  according  to  com- 

position, sources, 
and  texture,  281 
302. 

,,  ,,  according  to  rela 

tive  density,  89 
92. 

,,  ,,   according  to  sapo 

nification  equiva 
lents,  158. 
,,  ,,  according  to  uses 

302-339. 
,,  of    soaps   according   t< 

alkalinity,  512. 
"Clay,  China— see  China  clay. 

, ,     use  of,  in  refining  oils,  &c. ,  255 


Cleansing  engine  waste,  237. 
>loez,  elseococca  oil,  291. 
)lose  soap,  468,  473. 

,,     test  (flashing  point),  126. 
)loth  dressing,  use  of  oils  for,  302 
Coagulate  (grease  recovery),  271,  272. 
Coagulation  of   mucilage   and   albu- 
minous matters — see  Oils,  clarifica- 
tion of. 

Joaltar  oils — Sfc  Oils  (coaltar). 
)obalt  compounds  as  driers,  314. 
Cochineal  as  indicator,  420,  497. 
Jod  livers,  extraction  of  oil  from,  247. 
Joefficient  of  expansion  of  glass,  77. 
oils,  79,  92-94. 

,,  friction  in  capillary  tubes,  107. 
,,         ,,    Traube's  apparatus,  109. 
ogan's  process  (oil  refining),  259. 
ohesion  figures,  48,  345. 
Coils,  steam  -  see  Steam (wetand  dry). 
?'0kernut,  machine  for  splitting,  224. 
,,  oleine — see  Oleine  (cokernut). 
,,  spelling  .of  word,  3. 
,,   stearine— see    Stearine    (coker- 
nut). 
^old    drawn    oils  —  see    Oils     (cold 

drawn). 

,,      press  cake,  375. 
,,          ,,     (candle     stearine),     231, 

355,  368. 

, ,      process      soaps  —  see      Soap- 
making. 
Colloidal  mucilage,  255. 

, ,     state  of  soap,  458, 466, 481, 485. 

,,  ,,     facilitated  by  presence 

of    alcohol, 

sugar,  glycerol, 

458,  481. 

,,  ,,  ,,  by  use  of  castor 

oil,  481. 

,,  ,,  ,,  by  use  of  potash 

instead  of  soda, 

459,  481. 
Colorimeter,  50. 

Colour  of  boiled  oils,  315. 

oils,  49,  263,  341. 
Colour  reactions  with  nitric  acid,  139. 

153. 
,,  ,,     sulphuric       acid, 

151-153. 
,,  ,,    zinc,  chloride,  &c., 

141,  151-154. 

, ,  of  seal,  whale,  liver, 

arid  fish  oils,  294. 

Colouring  matters  contained  in  oils, 

49,  263. 

,,  ,,          for  candles,  405. 

Colza  (rape,  coleseed),  various  species 
of,  348. 


INDEX. 


537 


Combustion,   destruction  of  noxious 

smells  by,  247,  250. 
Composite  candles — see  Candles. 
Composition  of  mixtures,  calculation 

of,  172. 

,,  soaps  by  analysis — see 

Soaps,  commercial. 
,,  soaps,  calculated — see 

Calculations. 
Compound  ethers,  3,  4,  15. 

,,  ,,       saponification  equi- 

valent of,  158. 

,,  ,,       synthesis  of,  13,  17- 

Condensed  ricinoleic  acids — see  Poly- 
merised. 

Congealing   temperatures — see  Melt- 
ing points. 

Consistency  of  elaidin   formed — see 
Elaidin ;    also  Classification 
according    to    chemical   na- 
ture, &c.,  pp.  281-300. 
,,      of  oils,  &c.,  47. 
,,      tester,  Legler's,  139. 
Cooling  pans  (candle  stearine),  366. 
Copper  and  nitric  acid  test,  137,  139. 
,,     compounds  as  driers,  314. 
,,     contained  in  glycerine,  515. 

,,         in  oils,  121-124. 
, ,     soaps,  use  of,  in  refining,  263. 
,,     sulphate,  use  of,   in  refining, 

256,  263. 

, ,    test  for  drying  oils  (Hiibl),  133. 
,,    test  for  sugar  in  soaps,  505. 
Coppers  for  soap  boiling — see  Kettles. 
Coprah  (copra),  crushing  and  grind- 
ing appliances,  219-221,  224. 
Correction  for  anhydro  derivatives, 

170. 

,,  ,,  errors  of   hydrostatic 

balance  and   hydro- 
meter, 82-84. 
,,  ,,  free  fatty  acids,  &c., 

170. 

,,  ,,  impurities       (alkalin- 

ity), 419. 
,,  ,,  temperature    (specific 

gravity),  79. 

Corrosion  of  bearings,  &c. — see  Acids, 
free  fatty  (detrimental 
effects  of),  and  Acids 
(mineral). 

,,        ,,  iron  by  fatty  acids,  277. 
Cosmetics,   oils  used  in  preparation 

of,  302. 

Cottonseed,  decortication  of,  224. 
, ,      stearine — see  Stearine  (cotton- 


,,      utilisation  of  a  ton  of,  304. 
Cowles,  candle  moulding  machines,  1 04 


Cracklings,  246. 

Crampton,  expansion  of  oils,  93. 
Creosote  oils,  2,  451. 
Jresol,  6,  16. 
"ressonnieres',  A.  and  E.  des,  drying 

soap,  447. 
Crocodile  fat,  299. 

Cross  and  Bevan,  melting  point  de- 
termination, 64. 
ZJrotonol,  288. 
Cruciferous   plants,   sulphurised  oils 

from,  123,  154. 
Crushing  rolls,  215,  218-220. 
Crutching  (soap),  438-440 
rystallisation,  fractional,  separation 

by,  112. 

,,          from  solvents,  23. 
,,          of   separation   cake  —  see 

Separation  cake, 
rystallising  pans  (stearine),  367. 
Culinary  uses  of  oils  and   fats — see 

Oils  (cooking). 
Cupreol,  16. 

Curbs,  432,  433,  453,  469. 
Curd  soap — see  Soapmaking. 
Curriers'  grease,  326. 


DALICAX'S  process  (tallow,  &c.),  74. 
D'Arcet's  sulphuric  acid  process,  249. 
Dechan,  pharmaceutical  soaps,  510. 
Decolorising  of  oils — see  Oils,  bleach- 
ing of. 

Decomposing  pan,  stearine,  365. 
Decortication  of  seeds,  &c.,  223-225. 
,,  ,,  Dudley  and  Perry's 

chemical  process, 
225. 
Deering,  free  acids  in  rancid  tallow, 

355. 

Degras,  336. 
Degrees  (alkalies),   English,  French, 

and  German,  420,  421. 
,,         Burstyn's,  119. 
,,         Centigrade,  Reaumur,  Fah- 
renheit, 58. 
Dehydration,  formation  of  isoleic  acid 

by,  29. 
,,  of  oxystearic  acids,  29, 

39,  42,  46. 

,,  of  ricinoleic  acid,  36. 

Deitz,  extraction  apparatus,  235. 
Delphinum  phocasna,  20. 
Density — see  Specific  gravity. 
Deodorising  cokernut  oil,  261,  310. 
,,         soaps,  &c.,  267 — see  Ran- 
cid ;  Noxious  vapours. 
Descroizilles,  degrees  (alkali),  420. 


538 


INDEX. 


Destruction   of   noxious  vapours   by 

combustion,  247,  250. 
Destructive  distillation — see  Distilla- 
tion. 
Determination  of  fat  in  seeds,  &c. — 

see  Yield. 
Detrimental  effects  of  free  fatty  acids 

— see  Acids  (free  fatty). 
Detrimental  effects   of   free   mineral 

acids — see  Acids  (mineral). 
Diagometer,  53,  347. 
Diallyl,  oxidised  to  an  erythrol,  44. 
Dibromcamphor,  32. 
Dibromides  of  acids,  &c.,  27,  29-31, 

41,  43,  44,  176. 

Dibromo    substitution   derivatives- 
see  Substitution. 

Dichlorides  of  acids,  &c.,  26,  29,  31. 
Dichloro    substitution   derivatives — 

see  Substitution. 
Dichromate,     bleaching     with  —  see 

Bichromate. 
Dieff   and    Reformatsky,    ricinoleic 

acid,  40. 
Dierucin,  11. 
Dieterich,  iodine  number  of  linseed 

oil,  350. 

, ,     specific  gravity  of  fats,  88,  355. 
Digester,  for  extracting  bone  fat,  252. 
,,         Wilson's,  for  rendering  tal- 
low, &c.,  250. 
Diglycerides,  10,  468. 

,,         formed    by  action   of   sul- 
phuric acid,  144-147. 
,,         synthesis  of,  11. 
Diglycerol,  8. 

Diiodides  of  acids,  &c.,  26,  179-186. 
Diiodo   substitution  derivatives — see 

Substitution. 

Dikafat— see  Butters  (vegetable). 
Diminution   in    density   with   rising 

temperature,  92-94. 
Dippel's  oil,  2. 
Diricinolein     sulphuric     anhydride, 

147. 

Disintegrating  machines,  224. 
Dissolved  impurities,  256. 
Distearates,  23. 
Distearin,  468. 

Distillation  acetyl  number,  198. 
destructive,  2,  3,  5. 
Heyl's  apparatus,  234. 
of  carbon  disulphide  solutions, 

234-239,  254,  339. 
of  castor  oil,  20,  25,  40. 
of  dioxystearic  acid,  42,  46. 
of  glycerine,  513-516. 
of  oxystearic  acid,  25. 
of  ricinoleic  acid,  36,  40. 


Distillation    of     spirit     (transparent 

soap),  446. 
,,     of    turpentine    spirit    (Mein- 

ecke's  rosin  soap),  473. 
,,     under     diminished    pressure, 
14,    20,   21,  25,   28,  29,  34, 
36,  40,  41,  113. 
,,     under     diminished    pressure; 

technical  processes,  383. 
,,     with  superheated  steam,  110, 
113,  262,  271,  277,  278,  337, 
513,  514. 
,,     with  superheated  steam,  plant 

used  for,  382-386. 
,,     with  wetsteam,  22, 112,173-176 

— see  also  Reichert's  test. 
Distilled  grease  (Yorkshire),  277. 

,,    oleines — see  Oleines  (distilled). 
Dog  fat,  299. 

DogH  sh  liver,  extraction  of  oil  f  rom,247. 
Dragon's  blood,  19. 
Driers,  129,  262,  314-317. 
Dripping,  91,  303. 

, ,       tallow  adulterated  with,  354. 
Dry  fusion,  rendering  animal  fats  by, 

246. 

,,    steam — see  Steam. 
Drying  soap,  438,  447. 
Dubbin,  326. 
Dubrunfaut,  sulphuric  acid  process, 

380. 
Dudley  and  Perry,  chemical  decorti- 

cation,  225. 
Dugong    blubber,   extraction   of    oil 

from,  247. 

Dunn,  air  blast  in  soap  boiling,  433. 

, ,    boiler  (hydrated  soaps,  &c. ),  463. 

Dussauce,  ley  tanks  lined  with  lead, 

412. 

Dutch  liquid,  26. 
Dyer,  linseed  cake,  214. 
Dyestuffs  for  candles,  405. 


EARTHNUT — see  Oil  (arachis). 
Earthwax — see  Wax  (mineral). 
Edgerunners,  215,  218-221. 
Edible  uses  of  oils  and  fats,  302-312. 
Edinburgh  wheel,  391. 
Effect,     detrimental,    of    free    fatty 
acids— see  Acids  (free  fatty). 

,,     of  light  on  physical  properties 

of  oils  — see  Light  (effect  of). 
Efflux  viscosity — see  Viscosity. 
Egg,    white   of,   used    in    clarifying 

candle  stearine,  370. 
Elseococca  vernicia — see   Oil  (Elseo- 


INDEX. 


539 


Elaidin  reaction,  28,  40,  341. 

,,  ,,      methods  of  working, 

137-139. 
,,  ,,      solubility  diminished 

by,  55. 

Elbow  press,  202. 
Electrical  conductivity,  53. 

,,       method  (melting  points),  65. 
Elevators,  221-225. 
Ellinger,  Danish  butter,  53. 
Ellwood,  Valenta's  test,  57. 
Enfleurage,  302. 
Engine    waste,    grease    from  —  see 

Grease. 

Engler,  viscosimeter,  101. 
EnglerandKunkler,  viscosimeter,101. 
English  degrees  (alkali),  420. 
Entozoa  present  in  inferior  margarine, 

308. 

Envelopes  (oil  pressing),  217,  221. 
Equivalent   quantities   of    soda   and 

potash,  425,  426. 
Error  due  to  neglect  of  expansion,  77, 

78. 

Errors,  tables  of,  construction,  82-84. 
Equivalent,  mean,  of  fatty  acids— see 

Acids  (fatty). 

, ,  saponification  —  see    Sa- 

ponification  equivalent. 
Erucin  (erucic  triglyceride),  11. 
Erythrol,  4. 
Erythrols  from  diallyl  hydrocarbons 

by  oxidation,  44. 
Eschwege  seife,  461. 
Essential  oils— -see  Oils  (essential). 
Ester  number  (Esterzahl),  162,  195. 
Estrayer  cylinder  (oil  press),  204. 
Ether  as  solvent  for  lead  salts,  112, 
128,     136,     356, 
376,  501. 

,,     oils,  &c.,  55,   119- 

124,     231,     262, 

273,     328,     359, 

495-497,  501-503. 

Ether,    petroleum  —  see    Petroleum 

ether. 
Ethers,    compound— see    Compound 

ethers. 
Ethyl  acetate,  4. 

,,      linolate,  34. 
Ethylene,  action  of  chlorine  on,  26. 

,,         diacetate,  4. 
Eugenol,  194. 
Evaporating  point  (lubricating  oils), 

325. 
Evrard,   alkaline    tallow    rendering 

process,  249. 

Examination   of    oils,    &c.,    general 
scheme  for,  124. 


Expansion  of  glass,  77. 

,,  ,,    correction  for,  77,  78. 

,,  oils,  &c.,  Allen's  results, 

92. 

,,  ,,          Crampton's  re- 

sults, 93. 

,,  ,,          Lohmann's    re- 

sults, 94. 

,,  ,,          Wenzell's  re- 

sults, 93. 

Experimental  laboratory  press,  213. 
Expression  in  stages,  212. 
Extraction   of   oils  by  solvents,   ap- 
pliances for,  232-240. 
Extractive     matters,     fermentation, 
causes  hydrolysis,  10. 


FAHRENHEIT  scale,  57-59. 
Fahrion,  boiled  oil,  135. 
Fan  (soapboiliug),  433,  434,  460,  469. 
Farina  as  adulterant  of  fats,  123 — see 

Starch. 

Fat,  animal,  class,  282,  298. 
,,    nature  of,  1. 
,,     uiisaponilied,  determination   of, 

119. 
Fats,  animal,    expression   of   oleines 

from,  299. 

,,  ,,          from  birds,  298. 

,,  ,,          from  milk  (animal  but- 

ters), 174,  298-see 
also  Butter  (cow's). 
,,  ,,          from  reptiles,  299. 

,,  ,,         refining  and  bleaching, 

254-268. 

,,  ,,         rendering  of,  245-251. 

,,  ,,         tallow,    lard,    butter 

class,  282,  298. 

,,       vegetable — see  Butters,    vege- 
table. 
Fatty  acids — see  Acids,  fatty. 

,,       matters   in  seeds,   nuts,   &c., 

115,  237-244. 
Fawsitt,  sulphur  chloride  and   oils, 

155. 

Ferrous     sulphate     as     decolorising 
agent,  264,  269. 

,,  ,,  used  in  soap  mot- 

tling, 471. 

Fibre  from  cotton  seeds,  304. 
Ficus  gummiflua,  14. 
,,     rubiginosa,  16. 
Field,  Leopold,  candle  nut  oil,  287. 
,,         candles,  £c.,  in  the  Ro- 
man period,  363. 
,,         lamp  chimneys,  31 3. 
,,         soaps,  509. 


540 


INDEX. 


Field,  Leopold,  spermaceti,  360. 

,,         steariiie  plant,  369,  382. 
,,         wax  bleaching,  266. 
Figging  of  soft  soap,  459. 
Filling  (soap)— see  Soapmaking. 
Film  test,  133,  351,  352. 
Filsinger,  soap  analysis,  494. 
Filter  cake  (red  oils),  376,  377. 
Filtration  of  oils  without  extra  pres- 
sure, 257,  264. 
Filter  presses,  226-229. 

,,  use   in   clarifying  ex- 

pressed oils,  228, 

254-257. 
,,  ,,     in  purifying  red 

oils,  231,  376. 

Fiukener  on  Dalican's  method,  75. 
Firing  point  (ignition  point),  329. 
First  runnings,  304. 
Fish  livers,  extraction  of  oil  from,  247. 
,,     manure  from  residues  of  fish  oil 

extraction,  249. 

Fit  (coarse  or  fine)  of  soap,  471. 
Fitted  soap — see  Soapmaking. 
Fixed  oils — see  Oils  (fixed). 
Flambeau,  312,  362. 
Flashing  point,  125-128. 

,,       of  coaltar  oils,  &c.,  328. 
,,       of  lubricating  oils,  325- 

qoq 

o^y. 

,,  ,,     insurance,  325. 

,,       of  oleine  from  Yorkshire 

grease,  279. 

Flavour  of  oils,  &c. ,  49. 
Flax  plant,  349. 
Flaxen  wicks,  362. 
Fleeces — see  Wool. 
Fletcher,  thermhydrometer,  80. 
Floating  soaps,  441. 
Flour  as  adulterant  of  fats,  123 — see 

Starch. 

,,      in  beeswax,  359. 
Fluorescence,  50. 
Fob  (fitted  soap),  471. 
Foots,  115,  256,  259,  324. 

,,       avoidance  of  formation  of,  228. 
distillation  of,  261,  383. 
spermaceti,  261,  360. 
utilisation  of,  261,  324,  408. 
Formula,  alkaline  degrees,  421. 

,,          equivalent     quantities     of 

soda  and  potash,  426. 
,,          thermometer  degrees,  58. 
Foxy  colour  developed,  265,  266,  356. 
Fractional  crystallisation,  112. 
„          distillation,  113. 
,,          precipitation,  112. 

saturation,  112,  113. 
Frames  (soapmaking),  434-437,  444. 


Frederking,  oil  boiling  pan,  316. 
Free  fatty  acids— see  Acids,  free  fatty. 
Free  fire  process  of  boiling  oils,  315. 

,,        soap  pans,  427. 
Freezing  points — see  Melting  points. 
French  degrees  (alkali),  420. 
Fresenius,  absorption  of  oxygen,  134. 
Friction  coefficient,  Mills,  107. 

,,  Poiseuille,  107. 

Traube,  109. 
Fuel    from    cotton     and     sunflower 

seeds,  304,  305. 

Fullers'  earth,  use  in   refining  oils, 
&c.,  255. 

,,        grease,  272,  279. 

,,  ,,       valuation  of,  280. 

Fusel  oil,  use  in  woolscouring,  337. 
Fusel    oils    (fermentation    oils) — see 

Oils  (fusel). 

Fusing  points— see  Melting  points. 
Fusion  with  alkalies — see  Hydrogen. 


GALIPOT  resin,  88. 
Gay  Lussac,  candle  material,  365. 
degrees  (alkali),  421. 
Geitel,  stearolactone,  38,  145. 

,,      sulphuric  acid  and  oils,  144. 

,,      — see  Schepper  and  Geitel. 

Gelatin,  removal  of,  from  fish  oils,  &c., 

256,  263. 
,,        use  of,  to  remove  colouring 

matters,  &c.,  263. 
Gellatley,    spontaneous    combustion, 

132. 

Geraiiic  aldehyde,  15. 
Geraniol,  15. 
Gerlach,  specific  gravity  of  potassium 

carbonate  solutions,  419. 
,,       vaporimeter       (glycerine 

valuation,  519. 
German  degrees  (alkali),  420. 

,,        sesame  —see  Oil,  Camelina. 
,,        soap  process,  449,  472. 
Girard,  solubility  in  alcohol,  54. 
Glacial    acetic    acid  test — see    Acid 

(acetic). 
Gladding's    process,    rosin    in   soap, 

485,  501,  502. 

Glass,  expansion  of— see  Expansion. 
Glassner,  nitric  acid  test,  141. 
Glycerides,  3,  9. 

,,          determination  of,  in  lub- 
ricants, 329. 
,,          hydrolysis    of,    in    three 

stages,   10. 

,,          iodine  absorbed  by  pure, 
180. 


INDEX. 


541 


Glycerides,    mixed— see    Mixed   gly- 

cerides. 
,,  saponification  equivalents 

of  pure,  158. 
„  ,,    of,  in  three  stages, 

468. 

.,  synthesis  of,  11. 

Glycerine,  manufacture   of  (glycerol 

extraction),  513-516. 
,,          analysis  and  detection  of 

impurities,  515. 

,,  extraction  from  soap  leys, 
451,  468,  469, 
541. 

,,  ,,  from  soap  leys,  com- 

position, 514. 
,,  ,,  from  sweet  waters, 

513,  514. 

,,          loss  in  sulphuric  acid  hy- 
drolysis processes,  381. 
,,          production  in  candlemak- 
ing  processes,  311,  366, 
373,  385,  513. 

, ,          production  in  soapmaking 
processes,     450,      45 1 , 
466-470. 
,,          valuation,  acetyl  process, 

8,  191,  516. 
,,  ,,     bichromate   process, 

8,  516. 

,,  ,,     David's  process,  522. 

,,     litharge       „        524. 

,,     Muter's       ,,       523. 

,,  .,     oxalic  acid  process, 

8,  519. 
,,  ,,     by  specific  gravity, 

516,  517. 

„  ,,     by   tension    of  vap- 

our, 518,  519. 

, ,  yield  from  ox  fat,  311,312. 
,,  ,,  practical,  from 

various  glycerides, 
521. 

„  ,,     theoretical,  162, 195. 

Glycerine   soaps — see   Soaps  (special 

kinds). 
Glycerines  (commercial  products),  8, 

110,  513. 

Glycerol,  4,  7,  110,  513.  [144. 

,,  action  of  sulphuric  acid  on, 
,,  ,,  heaton— see  Acrolein. 
,,  as  standard  in  viscosi- 

metry,  101. 
,,        calculated   yield   from    tri- 

glycerides,  521. 
,,        crystallised,  7.  514. 
,,        formation  during  examina- 
tion of  oils,  124. 
,,          ,,  from  allylic  alcohol,  44. 


Glycerol,  formation  on  saponifying 
adulterated  beeswax, 
359. 

,,  ,,011  saponifying  adulter- 

ated sperm  oil,  354. 
,,  ,,  on    saponifying    Tur- 

key red  oils,  as  a  test 
33-1 

,,          physical  properties  of,  7. 
,,          qualitative  tests  for,  8,  516. 
,,          quantitative— .see  Glycerine, 
manufacture    of    (valua- 
tion). 

,,  retained  in  cold  process 
soaps,  &c. ,  450, 
456-466. 

,,  ,,     calculations  respect- 

ing, 464-466. 
Glycol,  4. 

,,       from  Carnauba  wax,  5,  18. 
,,         ,,      defines  by  oxidation,  44. 
Goat's  tallow— see  Tallow. 
Goods,  "killing"  of,  in  soapmaking, 

433,  468. 
,,      rancid,  deodorising  soap  made 

from,  267. 

Goose  grease,  68,  184,  298,  299. 
Gossage,  method   of    emptying  soap 

pans,  434. 

Graf,  theobromic  acid,  22. 
Grain  spirit  fusel  oils,  14. 
Graining  soap — see  Soapmaking. 
Granulating   presscake — see   Separa- 
tion cake. 

Grape  fusel  oils,  20. 
Grease,  birds,  298. 

,,       bone— see  Bone  grease. 

,,       curriers',  336. 

,,       distilled,  111 -see  Distillation. 

„       engine  waste,  236,  279,  324. 

,,       from   hot  pressing  — see  Hot 

press. 

,,       from  silk  soap  suds,  279. 
,,       fullers',  279,  2hO. 
,,       horse,rnare's — .see  Oils  (horse). 
,,       lubricating — see  Lubricants. 
,,       recovered,  262,  270-280. 

, ,       used  in  soapmaking, 

450,  453. 

,,       recovery  by  Yorkshire  pro- 
cess, 272 — see 
Yorkshire  grease. 
,,  ,,         by  lime  process,  271. 

,,       trade  refuse  (tannery  grease. 

&c.),  299. 

,,  ,,  used     in     soap- 

making,  409. 

,,       Yorkshire  —  see     Yorkshire 
grease. 


542 


INDEX. 


Greasy  rags,  spontaneous  combustion 
of,  132,  133. 

Greaves,  246. 

Green  liquor — see  Chrome  liquor  re- 
covery. 

Green  oil  (Yorkshire  grease  distilla- 
tion), 277. 

Grills  and  Schroeder,  liquid  sulphur 
dioxide  as  solvent,  236. 

Grimshaw,  phosphated  soaps,  476. 
, ,    utilisation  of  cotton  seeds,  304. 

Grittner  and  Szilazi,  rosin  in  soap,  502. 

Grb'ger,  dioxy palmitic  acid,  44. 

Ground  mica  (antifriction),  324. 

Groundnut  —  see   Arachis   nuts   and 
Oil  (arachis). 

Ground  plan  of  16-press  installation, 
216. 

Gum  arabic,  Eideal,  108. 
,,    benzoin,  19. 

Gumming  of  oils,  129,  322,  325. 

,,  ,,      practical  test  of,  323. 

Gwynne,  Jones,  andWilson,  sulphuric 
acid  process,  380. 

H 

HAUEMAN,  soda  crystals  in  oil  refin- 
ing, 2GO. 

Hagenbach,  viscosity,  107. 
Hager,  specific  gravity  of  fats,  88,  355. 
Hairs,  hair  envelopes,  217,  221. 
Handpicking  seeds,  necessary  to  ob- 
tain standards,  213,  340,  350. 
Hartley,  acid  refining  process,  259. 
,,        manganese   sulphate   in  re- 
fining, 260. 

Hartley  and  Blenkinsop,  patent  re- 
fining process,  263,  264,  315. 
Hauchcorne,  nitric  acid  test,  140. 
Haussknecht,  benoxylic  acid,  45. 
,,  brassa'idic  acid,  28. 

Hawes'   boiler   (cold   process   soap), 

457,  463. 

Hazura,  characteristic  oxidation  pro- 
ducts, 128. 

,,        oxidation  of   stearolic  acid, 

36  —  see     "Benedikt     and 

Hazura ;  Bauer  and  Hazura. 

Hazura  and  Grlissner,  glycerides  in 

linseed     oil,    350, 

351. 

,,  ,,    liuolic  acid,  35. 

,,  ,,    linolic  acid  in  olive 

oil,  344. 

,,  ,,    oxidation  of   drying 

oil  acids,  136. 

,,  ,,      ,,      of    ricinoleic 

acid,  40. 


Hazura  and  Griissner,  oxidation    of 
stearolic  acid,  45. 
,,  ,,    rule  concerning  oxi- 

dation, 44. 

Head  matter  (whales),  360. 
Heat,     coagulation     of     albuminous 

matter  by,  255,  263. 
,,        effect   of,    on    oils — see    Oils 

(effect  of  heat  on). 
,,        evolution  with  sulphuric  acid 

— see  Oils  (heat  evolution). 
Hehner,  beeswax,  357,  358. 

, ,         glycerine  valuation,  516, 522. 
number,   113,  157,  166-170, 

195,  196,  341. 
Heintz,  melting  point  tables,  71-74. 
Hell,  hydrogen  method,  13,  121. 
Hempen  wicks,  362. 
Hersee,  soap  pump,  434. 
Hervieux  and  Bedard,  waggon  grease, 

327. 

Hess,  Yorkshire  grease  analysis,  276. 
Hexacetyl  derivatives,  37. 
Hexbromides   of  fatty  acids,   34-37, 

176. 

Heyl,  distillation  apparatus,  234. 
Hippopotamus  grease,  299. 

milk,  298. 

Hoffmeister,  chilling  baths,  67. 
Holde,  improved  flashing  point  ap- 
paratus, 127. 
,,     iodine    absorption    of    drying 

oils,  184,  351. 
,,     oleorefractometer,  52. 
Holt,  brassic  acid,  29. 
Homologous  acids,  separation  of,  112, 

113. 
Homologues  of  linolic  acid  (supposed), 

32,  34. 

Honig  and  Spitz,  extraction  appara- 
tus, 120,  239. 

Hope,  soap  analysis,  494, 498, 499, 509. 
Horse    grease,    horse    fat  —  see    Oil 

(horse). 
,,     power  requisite  in  oil  mill,  215- 

217. 

Hot  baths,  61-65,  80,  95-101. 
Hot  air  bleaching  processes — see  Air. 
Hot  press,  231,  368. 

cake,  368,  370,  375. 
Hubl,  beeswax,  358. 

,,      iodine  test— see  Iodine  number. 

,,      melting  points,  71. 

,,      modification  of  Livache's  test, 

133. 

Hubl  and  Stadler,  rosin  in  soap,  502. 
Huiles  d'enfer,  344. 

tournantes,  116,  344. 
Hulls  from  cotton  seed,  304. 


INDEX. 


543 


Hurst,  efflux  viscosity  values,  105. 
,,       \ralenta's  test,  56,  57. 
,,      viscosimeter,  101. 
,,      Yorkshire  grease,  276-279. 
Hyaena  fat,  21. 

Hydrated  soaps — see  Soapmaking. 
Hydration  of  anhydrides,  &c.,  41-43, 

45. 

,,          of  isoleic  acid,  38. 
Hydraulic  filter   press  —  see   Filter 

press. 

presses,  207-212,  215-218. 
Hydriodic    acid,    action    on    isoleic 

acid,  30. 
,,  ,,     action  on  linolic  acid, 

34. 
Hydrocarbons,  2,  3,  5,  54,  90. 

, ,         detection  in  linseed  oil,  352. 
,,  ,,     in  olive  oil,  347. 

„  5,     in  rape  oil,  349. 

,,  ,,     in  Turkey  red  oils, 

335. 

,,  ,,     in    wax    and  sper- 

maceti, 359,  361. 
,,         determination     in     lubri- 
cants, 329. 
,,         insoluble  in  glacial  acetic 

acid,  57. 
, ,         mineral,  solid — see  Cerasin, 

Ozokerite. 
,,         miscible  with  blown  oils, 

320,  321. 

,,         presence    of,    in    distilled 

oleines,  &c.,  120,  258, 

261,274-278,377,378. 

,,  ,,      in    engine     waste 

grease,  279. 
,,         saturated  and  unsaturated, 

3,  26. 
,,         separation    of,    from    oils, 

119-124. 
,,         use  of,  in  manufacture  of 

lubricants,  322-329. 
,,         used  as  adulterants,    120, 

121,  335,  347-349,  352. 
Hydrocarotin,  18. 

Hydrochloric    acid,     evolved     from 
burning  wax  tap- 
ers, 267,  365. 
,,  ,,     formed  in  Turkey  red 

oil  making.  331. 
,,  ,,     removal  of  lime  salts 

from  bone  fat  by,  256. 
,,  ,,     used    in    grease    re- 

covery, 271. 
,,  ,,         ,,    in  Mege  Mouries 

process,  308. 

,,  ,,         ,,    in      oleic     acid 

valuation,  376. 


Hy  drochloricacid  used  with  bleaching 
powder,   &c.,  in  decolorising  oils, 
&c.,  264-266. 
Hydrogen,  atmosphere  of,  in  cod  liver 

oil  extraction,  248. 
,,          evolved    by    fusion    with 
alkalies,       from 
acrylic  acids,  24. 
,,  ,,  from  alcohols,  13,  121. 

,,  ,,  from  glycols,  18. 

,,  ,,  from    gly collie    acids, 

37. 
,,          nascent,  as  dechlorinising 

agent,  31,  35. 
,,          peroxide      as      bleaching 

agent,  264,  339,  359. 
Hydrogenation  of  acids,  20,  26,  32, 

34,  40. 

aldehydes,  14,  15. 
Hydrolysis    accompanies    rancidity, 

10,  12,  114,  292. 
,,       but  little  effected  by  light, 

131. 
,,       by  superheated  steam,    10, 

110,  125,  261. 

,,       in    autoclaves,      &c.,      373 

— see     also    Distillation. 

,,       of      condensed      ricinoleic 

acids,  146,  333. 

„       ofoils,&c.,7, 10, 12, 114, 116. 
,,       of   soap   solutions,    12,   23, 

486-488. 

,,  of  soap  solutions,  rate 
diminished  by  presence 
of  alkali,  487. 

,,       of     sulphuric     acid      com- 
pounds, 27,  29,  331,  333. 
„        of  Turkey  red  oils,  331-333. 
,,        water  taken  up  during,  10, 

275. 
Hydrometer,  77. 

,,  scales,  84-86. 

,,  table    of     errors,    con- 

struction of,  83. 
Hydrostatic  balance,  77-79,  81. 

,,  table  of  errors,  construc- 

tion of,  83. 
Hydroxylinolein,  136,  137. 


ICELAND  moss  in  lard,  306. 
Ignition  point,  329. 
Illipti  fat — see  Butters,  vegetable. 
Impurities,    systematic   examination 

for,  124. 
Incipient    melting     and    solidifying 

points — see  Melting  point. 


544 


INDEX. 


Increment  in  weight  during  drying  of 

fatty  acids,  113. 
Increment  in  weight  during  drying  of 

oils,  133. 

Indicators     in     titration,    420  —  see 
Phenolphthalein,  Titration,  Cochi- 
neal, Litmus,  Methyl  orange. 
Indigo,  used  to  tint  soft  soap,  459. 
Inner  anhydrides,  30,  39. 
Insolation,  effect  of — see  Light,  effect 

of. 

Insoluble  acid  number,  168,  195,  341. 
,,         f  atty  acids— >ee  Acids,  fatty, 

insoluble. 

Installation  (16-press),  plan  of,  217. 
Insurance  companies  and  lubricating 

oils,  325. 
Iodine  candles,  407- 

,,      number    (iodine    absorption),. 

26,34,157,176-186,341. 

,,          ,,      as      test      of      drying 

power,  133. 

,,  ,,      effect  of  light  on,  131. 

,,  ,,      lessens  as  oxysen  taken 

up,  42,  129,^135,  185. 
,,  ,,      of  free  acids,  180,  184, 

197,  356. 

,,  ,,      of  glyceride  falls  short 

of  that  of  free  fatty 

acid  by  about  4-5  per 

cent.,  185,  197. 

,,          ,,      of  oils,  determinations 

of,  181-184,  196. 
lodo     substitution     derivatives — see 

Substitution. 

Irish  moss  (antifriction),  328. 
Iron,    cast,    less    corroded   by  fatty 
acids  than  wrought  iron,  277. 
,,      salts,  use  in  refining,  263. 
,,      soaps — see  Metallic  soaps. 
Isocholesterol,  16,  17. 

, ,  and  ether s  in  Yorkshire 

grease,  272-276. 
Isoglyceride  theory,  12. 
Isomerides  of  dioxybenic  acid,  28,  29, 

44,  129. 
,,  dioxystearic  acid,  28,  30, 

41,  43,  129. 
linolic  acid,  32,  35. 
ofoleicacid,  28,  29,  129. 
oxystearic  acid,  29,38,39. 
oxystearosulphuric  acid, 

27,  30,  38. 

ricinoleic  acid,  40,  41. 
trioxystearic    acid,     40, 

43,  44,  129. 
Isomerism  of  brassic  and  erucic  acids, 

28,  29. 
,,          stereochemical,  29. 


JACKSON,  African  oils,  289. 
Japanese  wax — see  Wax  (Japanese). 
Jean,  adulteration  of  butter,  310. 

,,   oleorefractometerreadings,  51-53. 

,,   thermeleometer,  151. 
Jellifying  of  soap  solutions,  485. 
Johnson  &  Co.,  filter  presses,  229. 
Juillard,  Turkey  red  oils,   147,  330, 
333. 


KAOLIN  as  adulterant,  123. 

Kauri  gum  admixed  with  thickened 

oils,  &c.,  142,  318. 
Keg  lard,  306. 
Kerosene,  2,  5. 
Ketones,  3,  6. 
Kettles  for  boiling  drying  oil,  315, 316. 

,,    for  boiling  soap,  free  fired,  426- 
428. 

,,    for  heating  crushed  seed,  &c., 
215,  221. 

,,    heated  by  dry  steam,  247,  428. 

,,         ,,      by  wet  steam,  428. 

,,    skimmer  pipe  for,  433. 

,,    square,  433. 

,,    various  older  forms  of,  429-432. 
Kitchen  grease,  299,  408. 

,,  ,,       deodorising,  265. 

,,       tallow      adulterated 

with,  354. 

Kcettstorfer's  test  (Kcettstorfer  num- 
ber)— see  Total  acid  number. 
Kidney  fat  (ox),  311. 
"  Killing  the  goods,"  433,  468. 
Knab's   superheated    steam   distilla- 
tion plant,  382. 
Kohn,   qualitative  test  for  glycerol, 

516. 
Krafft,  ricilinolic  acid,  36. 

,,       ricinic  acid,  41. 
Krafft  and  Noerdlinger,  brassic  and 

elaidic  acids,  28. 

Kingzett,  glycerine  extraction,  514. 
Kulp  livers,  extraction  of  oil  from, 

247. 


LABOUR  requisite  in  oil  mill,  215-218. 

Lach,  candlenut  oil,  287. 

,,  French  candle  stearine  plant,  386. 

Lactucerol,  16. 

Lamp  for  carbon  disulphide  (disin- 
fecting), 407. 


INDEX. 


545 


Lamps,  312,  313,  362. 
Langbeck,  lanolin  339. 
Langlet,  thermal  areometer,  82. 
Lanolin,  274,  336,  337-339. 
,,       in  soaps,  448. 
,,       manufacture  of,  337. 
,,       sulphurised,  339. 

tests  of  quality  of,  339. 
Lant  Carpenter,  lubricating  oils,  325. 
,,  soap  analysis,  510. 

,,  soap  boiling,  470. 

,,  sulphuric   acid   pro- 

cess, 381 ,  388. 
Lard,  21,  164,  299,  303-308. 
,,      adulteration  of,  306,  307. 
„      artificial,  307. 
,,      damaged,  used  for  soapmaking, 

408. 
„      free  fatty  acids  in,  small  when 

fresh,  307. 
, ,      iodine  number  of,  181-184,  307, 

356. 

,,      manufacture  of,  306. 
,,      melting  point  of.  68,  306,  307. 
,,      oil — see  Oil  (lard). 
,,      Reichert  number  of,  175. 
,,      saponification     equivalent    of, 

160,  307. 

,,      solid  suspended  matters  in,  123. 
,,      solubility  of,  56. 
„      specific  gravity  of,  88-93,  307. 
,,      stearine    (solar   stearine)  —  see 

Stearine  (lard). 
,,      unsaponifiable  constituents  in, 

&c.,  257,  307. 
,,      vegetable,  305,  310. 
,,      water  contained  in,  122,  307. 
Laurent,  polarimeter,  50. 
Laurie  aldehyde,  14. 
Laurin,  lauric  triglyceride,  11. 
Lead  acetate,  use  in  boiling  oils,  262, 

314. 

„     contained  in  oils,  121-124,  314. 
, ,     oxide  as  saponifying  agent,  410. 
,,     oxides  as  driers,  314. 
,,     plasters,  410,  485. 
, ,     salts  soluble  in  ether — see  Ether 

as  solvent. 

, ,     salts,  use  of,  in  refining,  256, 263. 
,,     test  (Livache's),  133. 
Leather  currying,  leather  grease,  302, 

336,  339. 

Leblanc  process  of  alkali  manufac- 
ture, 410. 
Lecithin,  121,  240,  259. 

,,        determination  of  phospho- 
rus in,  124,  240. 
Leeds,  soap  analysis,  494. 
Lefebre,  oleometer,  79. 


Leffmann  and  Beam,  Reichert  number, 

175. 

Legler,  consistency  tester,  139. 
Lenz,  density  of  glycerol  solution,  517. 
Lepenau,  leptometer,  106. 
Leuner,  bonefat  extraction  apparatus, 

253. 

Lever  presses,  199. 
Lever  and  Scott,  carbon  tetrachloride 

as  solvent,  236. 
Levinstein,  lanolin,  339. 
Lewkowitsch,   acetylation    test  and 
modification  thereof, 
189-191,  198. 

, ,  distillation  under  dim- 

inished pressure,  383. 
,,  rosin  in  soap,  502-504. 

, ,  Yorkshire  grease,  272. 

„  analysis 
of,  274. 

Leys,  alkalinity  of — see  Alkalinity. 
, ,     calculations  respectingquantity 
and  strength  of — see  Calcula- 
tions. 

, ,     causticising — see  Causticising. 
,,     spent— see  Soapmaking, Glycer- 
ine manufacture. 
,,     use    of,    in    soapmaking  —  see 

Soapmaking. 
Liechti  and  Suida,  sulphuric  acid  and 

oils,  144. 
Liebig,  distillation  of  acids,  fractional 

saturation,  112. 
Light  coaltar  oils,  2. 

, ,      petroleum  distillate — see  Petro- 
leum ether. 
Light,  effect  of,  on  oils — see  Oils,  effect 

of  light  on. 
, ,      facilitates  air  bleaching  of  wax, 

268,  269. 
,,      polarised  (polariscope),  17,  50, 

347,  352. 
,,  ,,          sugar    valuation   in 

soap,  505. 

Limburg  cheese,  20. 
Lime,  use  of,  in  causticising  alkalies 
— see  Causticising. 
,,          ,,        making      railway 

grease,  327. 

,,          ,,         recovering  grease,  270. 

,,          ,,         refining  oils,  256,  261. 

,,         steariue  manufacture, 

365,  369. 

Lime  rosin  soap  (railway  grease),  327. 
Lime  soap  (grease  recovery),  271. 
,,         in      candlemaking  —  see 

Candle  stearine. 
,,          in  lard,  307. 

in  lubricants,  324,327,328. 
35 


546 


INDEX. 


Limpach,  stearolic  acid,  36. 

Linoleum,  302,  318,  319. 

Linolic  anhydride,  125. 

Linolin  (linolic  triglyceride),  134, 139. 

Linoxyn,  134,  136. 

Linseed  cake — see  Oilcake 

Linseed,  sources  of,  349. 

,,        usually   mixed   with    hemp- 
seed,  349. 
Lint,  304. 

Litmus  as  indicator,  420. 
Liquid  waxes— see  Waxes. 
Litharge  as  drier — see  Driers. 
Livache,    comparative   action   of 

driers,  314. 

Livache's  test,  133,  351,  352. 
Livers,  fish  and  shark,  &c.,  extrac- 
tion of  oil  from,  247. 
Loading  (soap) — see  Soapmaking. 
Lcewe,  melting  points,  65. 
Lohmann,  expansion,  93. 
Lubricants,  analysis  of,  328-330. 

, ,      coarse,  27 1 , 280, 324, 326-328. 
,,      corrosion    by  free  acids  in, 

115,  260,  322. 
,,      for  hot  rollers    (pitch  from 

Yorkshire  grease),  277. 
,,      greases  (cart,  carriage,  wag- 
gon, railway  grease,  anti- 
friction grease,  &c.),  325- 
329,  409. 
.,      materials  used  for,  302,  321- 

328,  339. 

,,      use  of  blown  oils  for,  320. 
„      viscosity  of — see  Viscosity. 
Lubrication,  5,  48. 
Lunge  and  Hurter,  Beaume"  scale,  86. 
,,  ,,    specific  gravity  of  al- 

kalineleys,  416-418. 
Lupeol,  17,  259. 


M 


M 'NAUGHT,  pendulum  machine,  94. 
Magma  (grease  recovery),  271,  272. 
Magnesia  as  saponifying  agent,  379, 

410. 
,,         calcined,  use  of,  in  refining, 

256,  261. 

Magnesium  soaps,  121. 
Manganese    compounds,   use    of,   as 

driers,  314,  315. 

, ,  dioxide,  use  of,  in  bleach- 

ing, 268. 
,,  salts,  use  of,  in  refining, 

256,  260-264. 

Mangold,  glycerine  valuation,  521. 
Mannitol,  5. 


Mansbridge,    analysis    of    Yorkshire 

grease,  275,  276. 

Manteau  Isabelle  (mottled  soap),  472. 
Manure  from  fish  oil  extraction  resi- 
dues, 249. 

,,       scraps  from  ox  fat,  311,  312. 
,,       sludge  from   suds    and  sud- 

cake,  271,  2/2. 

Mare's  grease— -see  Oil  (horse). 
Margarin,  glyceride  of  artificial  mar- 

garic  acid,  21,  22,  110,  309. 
Margarine  (Oleomargarine,  Butterine, 
Artificial    butter,    Dutch 
butter,  Bosch,  Butter  sub- 
stitutes), 22,  114,  299,  305, 
308-312. 
,,     cokernut  and   palmnut   oils 

in,  310. 

,,     Hehner  number,  166,  310. 
,,     iodine  number,  181,  184,  310. 
,,     manufacture,  246,  247,  308- 

312. 
,,     manufacture  byMegeMouries 

process,  ;,08. 
,,     origin  of  name,  308. 
,,     Reichertnumber,173,174,310. 
,,     specific  gravity,  88,  91. 
, ,     total  acid  number  and  saponi- 

fication  equivalent,  159. 
,,     use  of  oleorefractometer    in 

detecting,  53. 
,,     vegetable,  305. 
Marine  soap  -  see  Soapmaking. 
Maritime  alkali — see  Barilla. 
Marix,  distillation  under  diminished 

pressure,  383. 
Marrow,  21. 

Massie,  nitric  acid  test,  141. 
Maumene's  test— see  Oils  (heat  evolu- 
tion). 

Meal  as  adulterant,  123. 
Mean   equivalent — see   Acids,   fatty, 

(mean  equivalent). 
Meats  from  cotton  seed,  304. 
Mechanical  viscosity  testers,  94. 
Mege  M  curies  process,  308. 
Meinecke's  process  (rosin  soap),  473. 
Meissl,  Beichert  number,  53,  174. 
Melting  points  (Congealing,  Solidifica- 
tion, Fusing,  Freezing 
points),    acetic     acid 
series,  20. 

,,       acrylic  acid  series,  25. 
,,       alcohols,  14. 
,,       candle  stearine,  370,375. 377. 
,,       cholesterol      and       allied 

bodies,  17. 

,,       congealing    of    lubricants, 
67,  325. 


INDEX. 


547 


Melting    points,     determination    of, 

60-67. 

„       distilled  fatty  acids,  384. 
,,       erucic    and    brassic     acid 

derivatives,  29. 

,,       mixed  fatty  acids,69-76,341. 
,,       oils  and  fats,  &c.,  67-69. 
,,       polyhydroxylated     stearic 

acids,  43. 

,,       propiolic  acids,  32. 
,,       synthetic  triglycerides,  11. 
Mercuric  bromide,  use  of,  in  Hiibl's 

test,  179. 

,,         nitrate,  colour  test,  151. 
Mercury  and  nitric  acid  test,  138. 
Merryweather  &  Sons,  improved  dry 

heat  rendering  arrangement,  247. 
Metallic  salts,  used  in  refining  oils, 

262,  263. 

soaps,  detection  in  olive  oil,  347. 
formed  in  paint,  135. 
in  lubricants,  324,  328. 
in  oils,  &c.,  121-124,  315, 

324,  485. 

in  ordinary  soaps,  410. 
iron  soap  in  mottling, 472. 
isolation  of  metallic  con- 
stituent (analysis),  328. 
Methyl  esters  (brassic  and  erucic),  29. 
,,       number  (methyl  iodide  test), 

157,  191-194,  196. 
,,       orange  as  indicator,  420,  497, 

507. 

Methylic  ethers,  5. 
Mica  (antifriction),  324,  328. 
Michaud  Freres,  glycerine  manufac- 
ture, 515. 
Milk  fats,  composition  unlike  that  of 

body  fats,  298. 
,,          Reichert  number,  174. 
Milling  machinery  (toilet  soaps),  446- 

448. 
Mills,  viscosity,  107,  108. 

,,      W.,  oil  bleaching,  264. 
Mills  and  Akett,  Mills  and  Snodgrass, 

bromine  absorption,  177. 
Milly,  de,  candle  material,  365. 

,,          wicks,  394. 
Mineral  acids,  injurious  effect  of — see 

Acids,  mineral. 
Moellon,  336. 

M oiler,  improved  cod  liver  oil  extrac- 
tion process,  248. 
Moinier  and  Bontigny,  candle  stear- 

ine,  369. 
Monoglycerides,  10. 

,,  synthesis  of,  11. 

Morawski  and  Demski,  iodine  absorp- 
tion, 184. 


Morfit,  oleine  soap  process,  453. 
,,       steam  series  of  soap  pans,  432. 
,,       steam  twirl,  428,  429. 
,,  ,,    use  in  making  lub- 

ricating grease,  325. 
,,  ,,    use  in  making  resin- 

ate  of  soda,  453. 

Mortars  (mortuary  candles),  406. 
Mottled  soaps — see  Soapmaking. 
Moulding,  Moulding  machine  (oil 

pressing),  215,  221-223. 
Mountain  ash  berries,  32. 
Mucilage   (vegetable   mucus),   deter- 
mination of, 
118-123. 

,,  ,,       removal    from 

oils— see  Oils 

(clarification). 

Miiller- Jacobs,    sulphuric    acid   and 

oils,  144. 

Muirhead   and  Alder   Wright,   zinc 
i    chloride  and  oils,  141. 
Mulder,  drying  oils,  134,  136. 
Muntz,  thermal  arceometer,  82. 
Muter,  colour  reactions,  142. 

,,       determination  of   oleic   acid, 

376. 

,,       olein  tube,  376. 
,,       specific  gravities,  88. 
Muter  and   Koningh,    separation   of 

fatty  acids,  307,  356. 
Mutton  tallow — see  Tallow. 
Myricin  (myricylicpalnritate),  4,  358, 

359. 

Myristic  aldehyde,  14. 
Myristin  (myristic  triglyceride),  11. 


N 


NATRON,  409,  449. 

Natural  naphtha— .see  Oils  (mineral). 
Negative  alkalinity,  498,  499. 
Negur  (negre,  nigre,  nigger)  of  fitted 

soaps,  471. 
Neill  &  Sons,  modern  soap  coppers, 

433. 

,,  rem citing  pans,  441. 

Neutral  oil  (Yorkshire  grease),  276- 

279. 
Neutralisation  number  of  fatty  acids, 

164, 169. 

,,  ,,    mixed  acids,  calcu- 

lation of  composi- 
tion from,  172. 
Nightlights,  312,  402. 

,,  manufacture  of,  406. 

Niin  fat,  Niin  wax,  302. 
Nitric  acid  test,  139,  153,  294,  341. 


548 


INDEX. 


Nitric  acid  as  standard  acid  in  soap 

analysis,  497. 
,,         use  of  in  wax  bleaching 

264,  265. 

Nitrous  acid  test — see  Elaidin  reac- 
tion. 

Nocciulo  (olive  marc),  343. 
Noerdlinger,  oilcakes,  114,  214. 
„  refining  oil,  263. 

,,  see   Krafft    and  Noerd- 

linger. 
Norton  and  Richardson,  linolic  acid, 

34. 
Noxious  smells  evolved  in  rendering 

animal  fats,  247,  249. 
Number,  acetyl — see  Acetylation  test. 
, ,       ester — see  Ester  number. 
, ,       free  acid — see  Acids,  free  fatty. 
,,       Hehner— see  Hehiier  number. 
,,       Hiibl— see  Iodine  number. 
,,       iodine  — see  Iodine  number. 
,,       insoluble  acid — see  Insoluble 

acid  number. 
,,       Koettstorfer — see  Total  acid 

number. 

, ,      methyl — see  Methyl  number. 
,,      neutralisation — see    Neutrali- 
sation number. 

,,      Reichert — see  Reichert  num- 
ber. 
,,      saponificatioii — see  Total  acid 

number. 
,,      soluble  acid — see  Soluble  acid 

number. 

, ,      total  acid — see  Total  acid  num- 
ber. 
, ,      volatile  acid — see  Volatile  acid 

number. 
Nuisance      in      rendering    fats — see 

Noxious  smells. 

Nutmeg  butter— see  Oil  (nutmeg). 
Nuts  strung  together  used  as  candles, 

363. 

,,     yield  of  fat  from  various  kinds 
of,  241-244. 


OAKBARK  infusion,  use  of,  in  refining, 

256,  263. 

Octylic  ethers,  5,  20. 
Odour  of  oils,  &c.,  49,  341. 

,,     rancid,  removal  of — see  Ran- 
cid, R,ancidity. 

CEnanthol    (oenanthic   aldehyde),  ac- 
tion of  acetic  anhydride  on,  25. 
, ,     formed  by  heating  castor  oil,  40. 
,,     hydrogenised  to  heptylic  alco- 
hol, 14. 


CEnanthol,  oxidised  to  heptoic  acid,  20. 

Oil.   For  the  specific  gravity  and  other 

physical  properties  of  each  oil 

severally,   vide  Chaps,   iv.,  v. 

(pp.  47-109). 

,,    For  the  chemical  properties  and 
reactions,  vide  Chaps,  vi.,  vii., 
viii.  (pp.  110-198). 
,,   acajou — see  Oil  (cashew). 
,,   adul,  288. 
,,    alligator     pear     (avocado     oil, 

persea  fat),  296. 
,,    almond,  3,  19,  241,  257,  283. 

class,  281,  282. 

,,         ,,         detection    of    adultera- 
tions, 347t 
,,    anchovy,  294. 
,,    angelica,  37. 
,,    anise,  192,  194. 
,,   apricot  kernel,  283. 
,,    American  walnut — see  Oil  (hic- 
kory nut). 

,,  arachis  (earthnut,  groundnut, 
peanut),  21,  25,  241, 
258,  283. 

,,         ,,   adulteration  of,  347. 
,,         ,,    detection  of,  in  olive   oil, 

344. 

,,         ,,    doubt  as  to  existence  of 
hypogseic  acid  in,  24,  111. 
,,         ,,    natural  variations  in  com- 
position of,  111. 
,,         ,,    relative  price  of,  342. 
,,         ,,    tests  for,  in  olive  oil,  344. 
,,         ,,    use    of,   in    soapmaking — 

see  Soapmaking. 
,,         ,,    used  as  lubricant,  322. 
,,    arctic  sperm — see  Oil  (doegling). 
,,    areca  nut,  241. 
,,    argan,  288. 
,,   assai  —  see    Butters,    vegetable 

(Para  butter). 
,,   avocado,  296. 

,,   bankulnut— see  Oil  (candle  nut). 
,,   beechnut  (beechmast)   241,  283. 
,,    belladonna  seeds,  241. 
,,   ben  (behen),  21,  25,  241,  283. 
„  detection  of  adulterations,  347. 
benne — see  Oil  (sesame^, 
bitter  apple — see  Oil  (colocynth). 
blackfish,  293. 
bladdernut,  288. 
boma  nut,  288. 
bone — see  Bone  fat. 
bottlenose  whale — see  Oil  (doeg- 
ling). 
brazil  nut  (castanha  nut),  241, 

242,  288. 
breadnut,  289. 


INDEX. 


549 


Oil,  cabbage,  115. 
,,    calabar   bean    (poon  seed,   dilo, 
domba,    pinnay,    tamanu   oil ; 
poona  fat,  tacamahac  fat),  241, 
291,  296. 

,,    camelina  (German  sesame",  gold 
of  pleasure),  241, 
286. 
,,          ,,          ,,  tests  for  sulphur  in, 

123. 

,,          ,,          ,,  use  in  soapmaking 
— see  Soapmaking. 
,,    canary— see  Oil  (Java  nut). 
,,    candle  nut  (bankulnut,  kekune), 

241,  287. 

,,    carapa   nut  (crab wood   nut   oil, 
touloucoona    oil,    coundi    oil, 
andiroba  fat),  242,  296. 
caryocar,  297. 
cashe\v  (acajou),  241,  289. 
cassia,  19. 

castanha — see  Oil  (brazil  nut), 
castor,  14,  20,  25,  43,  241,  285. 
,,   action  of   sulphuric  acid — 
see  Oils  (Turkey  red). 
,,    zinc  chloride  on,  141. 
blown,  321. 
class,  281,  284. 
effect  of  exposure  to  air,  136. 

,,         heat  on,  40. 
extraction    by    hot    water 

process,  200. 
relative  price  of,  342. 
soap — see  Soapmaking. 
soluble,  188,  321  —  see  Oils 

(Turkey  red). 
,,    use  in  soapmaking,  408. 
centaury,  242. 
chamomile,  14,  25. 
charlock,  241. 
chaulmoogra,  20,  242,  297. 
cherry  kernel,  283. 
Chinese  cabbage,  284,  348. 
chironji,  242,  289. 
cinnamon,  19. 
cloves,  194. 
cod  (lubricating),  330. 
cod  fish  and  cod  liver,  257, 258, 294. 
, ,  , ,    extraction  of,  247, 

248. 

,,  ,,    extraction  of,  ex- 

clusion of  air  dur- 
ing, 248. 

,,  ,,    relative  price   of, 

342  —  see    Oils 
(liver,  fish  liver). 
,,  ,,    used  for  soapmak- 

ing— see  Soapmaking. 
cokenmt,  20,  241,  257,  258,  295. 


Oil,  cokernut,  deodorisingrancid,261, 

310. 

,,  ,,         separation     of     coker 

stearine  from,  231, 
305  — see  Stearine 
(cokernut). 

,,  „         spelling  of,  3. 

,,  ,,         use  in  soapmaking — see 

Soapmaking. 

,,   colocynth  (bitter  apple,  241,  288. 
,,    colza  (cole,  cole  seed,  kohlsaat), 

348— see  Oil  (rape). 
,,    combo  nut,  242. 
,,    copra  (coprah)-see  Oil  (cokernut). 
,,    corn  poppy,  242. 
,,    cotton  seed,  241,  257,  258,  286. 
,,  ,,          absorption  of  oxygen 

by,  330. 

,,  ,,          action  of   sulphuric 

acid  on — see  Oils 
(Turkey  red). 

,,  ,,          adulteration  of,  347. 

,,  ,,          adulteration  of  lard 

with,  306-308. 

,,  ,,          as  lubricant,  322,325. 

,,  ,,          Becchi's   test    for — 

see  Becchi's  test. 
,,  ,,          blown,  319. 

,,  ,,          clarifying  and  refin- 

ing, 255-263. 
class,  281,  286. 

,,  ,,          refined,  use  as  edible 

and  cooking  oil,  and 
as  adulterant  of  sa- 
lad oils,  267,  304. 

,,  ,,         relative  price  of,  342. 

,,  ,,         use  in  soapmaking — 

s<>e  Soapmaking. 
,,  ,,         utilisation  of  a  ton  of 

cotton  seeds,  304. 
,,    coumu  nut  (coumu  butter),  289, 

297. 

„    cow  parsnep  (heracleum),  5, 14, 20. 
, ,    crab  wood  nut-see  Oil  (carapa  nut). 
,,    cress  seed,  241,  286. 
,,    croton,  20,  25,  287. 
,,    curcas  (purqueira,  purgir,  jatro- 

pha),  20,  285. 
,,   datura  (strammonium  seed),  21, 

244. 

,,    dilo,  291 — see  Oil  (calabar  bean). 

,,    doegling  (bottlenose  whale,  arctic 

sperm),  3,  25,258,300,360. 

,,        ,,    doubt    as    to   existence   of 

doeglic  acid  in,  24. 
,,       ,,    relative  price  of,  342. 
,,        ,,    yields  spermaceti  of  higher 
melting  point  thancachelot 
spermaceti,  360. 


550 


INDEX. 


Oil,  dogfish  liver,  247,  294. 

,,    dogwood  berry,  288. 

,,    dolphin,  293,  301. 

,,  ,,  bottlenose,  yields  sper- 
maceti, 301. 

,,  domba,  291 — see  Oil  (calabar 
bean). 

,,   dugoiig,  247,  293. 

,,    earth  nut — see  Oil  (arachis). 

,,   egg — see  Oil  (lien's  egg). 

,,  eleeococca  (Japanese  wood,  tung, 
wood  oil),  32,  291. 

,,  ,,  extremely  rapid  dry  ing 

qualities,  291. 

,,    eucalyptus,  6,  178. 

,,  ,,       medicated  candles,  407. 

,,    euonymus — see  Oil  (spindlenut). 

, ,  fever  nut — see  Butters,  vegetable 
(Borneo  tallow). 

,,    fish,  class,  281,  292. 

.,,  gamboge  (gamboge  butter),  242, 
296. 

,,    garlic,  15. 

,,    gaultheria-see  Oil  (winter-green). 

,,    geranium,  3,  15. 

,,  German  sesame" — see  Oil  (came- 
lina). 

.,,    gherkin  seed,  288. 

3,    gingelly — see  Oil  (sesame"). 

,,  gold  of  pleasure — see  Oil  (came- 
lina). 

,,  gourd  seed— see  Oil  (pumpkin 
seed). 

,,    grape  seed,  25,  242,  285. 

,,  green  (Yorkshire  grease  distilla- 
tion), 277. 

,,    groundnut— -see  Oil  (arachis). 

,,    gundschit — see  Oil  (lallemeiitia). 

,,    hammerfish,  294. 

,,    hazelnut,  242,  283. 

,,  hedge  radish  (hedge  mustard), 
284. 

,,   hempseed,  33,  35,  242,  257,  291. 

,,  ,,  detection  of ,  in  linseed 

oil,  352,  353. 

,,  ,,          use  as  cooking  oil, 304. 

,,  ,,  ,,  in  soft  soapmaking 

—see  Soapmaking. 

,,  ,,  usually  mixed  with  lin- 

seed oil,  349,  352. 

,,    henbane  seed,  242. 

,,   hen's  egg,  121,  298,  299,  408. 

,,    heracleum— see  Oil(cowparsnep). 

,,    herring,  294. 

,,  hickory  nut  (American  walnut 
oil),  242,  289,  291. 

,,    holly  seed,  242. 

,,  horned  poppy — see  Oil  (yellow- 
horn  poppy). 


Oil,  horse  (horse   grease,    horse    fat, 

mare's  grease),  286,  299. 
,,       ,,     deodorising,465-  see  Rancid. 
,,       ,,     use  in  soapmaking,  408. 
,,    horsefoot,  286. 
,,    horsechestnut,  242,  288. 
,,    Indian  cress,  242. 
,,   Japanese  wood— see   Oil   (elseo- 

cocca). 

,,    Japan  fish,  342. 
,,   jatropha — see  Oil  (curcas). 
,,   Java  nut,  Java  almond  (canary 

oil),  242,  296. 

,,    kekune— see  Oil  (candle  nut). 
,,    kulp  liver,  247,  294. 
,,    laintlaintain  seed,  289. 
,,    lallemantia  (gundschit),  242,  291. 
,,    lard,  231,  286,  307. 
,,      ,,      class,  2S1,  285. 
,,      ,,      relative  tendency  to  gum- 
ming, 323. 

,,      ,,      used  as  lubricant,  322,  325. 
,,    laurel  berry— see  Butters,  veget- 
able (laurel). 
,,   lettuce  seed,  243. 
,,    linden  seed,  243. 
,,    ling  liver,  178. 

„  linseed,  32-34,  243,  257,  258,  291. 
,,         ,,        acid  process  for  refining, 

259. 

,,        adulterations  of,  351, 352. 
,,        boiled,  262,  313-318. 

class,  281,  290. 
,,         ,,        film  test,  Livache's  test, 

133,  351. 
,,         ,,        iodine  number,  351  (see 

Iodine  number). 
, ,         ,,        pure,  only  obtainable  by 

handpickiiig,  350. 
,,         ,,        relative  price  of,  342. 
„         ,,  ,,      tendency  to  gum- 

ming, 323. 

,,         ,,        use  as  cooking  oil,  304. 
,,         ,,          ,,   in   soft   soapmaking 
— see  Soapmaking. 
,,         ,,        various    glycerides   con- 
tained in,  350,  351. 
,,    liver  class,  281,  292,  294. 
,,    louar,  294. 
,,    mabo  nuts,  289. 
,,    maccassar,  184,  297. 
„    madia,  243,  286. 
,,    maize,  243,  286. 
,,    malabar,  294. 
,,    malaka,  289. 
,,    manatee,  293. 
,,    mango  seeds,  289. 
,,    mang;osteen — see  Butters,  veget- 
able (goa  butter). 


INDEX. 


551 


Oil,  margosa— see  Oil  (zedrach). 
,,    menhaden  (porgie),  249,  258,  294. 
,,  ,,         relative  price  of,  342. 

,,    meni  seed,  289. 
,,    morse,  293. 
,,    m'poga  nut,  289. 
„   mustard,  15,  21,  25, 243, 234,  348. 
,,         ,,          tests  for  sulphur  in,  123. 
„   neat's  foot,  286,  298. 
,,  ,,  as  lubricant,  322, 325. 

,,  ,,          relative  price  of,  342. 

, ,    nettle  seed,  243. 
,,    neutral  (Yorkshire  grease),  276- 

279. 

,,    niger  seed  (ramtil),  243,  286,408. 
, ,  , ,         relative  price  of,  342. 

night  shade  seed,  243. 
niko  nut,  289. 

nimb  (neem)—  tee  Oil  (zedrach). 
nut  (walnut),  243,  291. 
nutmeg,  20,  243,  295. 
odal,  288. 

olive,  243,  257,  258,  283,  322. 
,,    absorption  of  oxygen  by,  330. 
,,    action  of  sulphuric  acid  on 

— see  Oils  (Turkey  red). 
, ,    adulterations  of,  344-347. 
,,    as  lubricant,  326. 
,,    class,  281,  282. 
,,    extraction    by    hot    water 

process,  200. 
,,   relative  price  of,  342. 
,,    relative   tendency  to  gum- 
ming, 323. 
,,    sources  and  production  of, 

342-344. 
,,    taste  improved  by  presence 

of  free  acids,  116. 
,,    used    for    soapmaking — see 

Soapmaking. 
olive  kernel,  243,  343. 

,,          ,,        extraction  of,  343. 
oolachan,  294. 
opochala,  288,  289. 
owala,  288,  289. 
palm  (palm  butter),  21,  243,  257, 

295,  322. 

,,    bleaching  processes,  264, 265. 
,,     as    candle    material  —  see 

Candle  stearine. 
,,     extraction  of,  by  hot  water 

process,  200. 
, ,     use    in    soapmakiug  —  see 

Soapmaking. 

palmkernel(palmnut),20,243,295. 
,,  extraction    by    sol- 

vents, 200. 

, ,  use  in  soapmaking — 

see  Soapmaking. 


Oil,  pea,  121,  259. 

peach  kernel,  243,  283. 
peanut — see  Oil  (arachis). 
pelargonium,  20. 
pilchard,  161,  294. 
pine — see  Oil  (red  pine), 
pinnay,    291 — see    Oil    (calabar 

bean). 

piquia  (pekea),  297. 
pistachio  nut,  244,  289. 
plum  kernel,  283. 
poppy  seed,  33,  243,  257,  291. 
, ,       relative  price  of,  342. 
, ,       use  as  cooking  oil,  304. 
,,        ,,    in  soft  soapmaking 
— see  Soapmaking. 
porpoise  (Delphinus  phocsenaoil), 

247,  293. 

,,         contains  valerin,  301. 
ponga  —  see   Butters,    vegetable 

(karanja  butter), 
poon  seed — see  Oil  (calabar  bean), 
poondi  —  see   Butters,   vegetable 

(karanja  butter), 
porgie — see  Oil  (menhaden), 
pumpkin  seed  (gourd  seed),  243, 

288. 
purgir  nut  (purqueira,  jatropha, 

curcas) — see  Oil  (curcas). 
radish  seed,  244. 
ramtil  — .see  Oil  (niger  seed), 
ray  liver,  294. 
rape  (colza),  21,  25,  49,  257-259, 

284,  313,  322. 

,,     absorptionof  oxygen  by,  330. 
,,     adulteration  of,  349. 
,,     as    standard    of   viscosity, 

101,  349. 

,,     blown,  319,  320. 
,,     class,  281,  284. 
,,     fatty  acids   and  glycerides 

contained  in,  11,  41. 
,,     injurious     effects    of    free 

acids  on,  115,  313. 
,,     insoluble  in  acetic  acid,  55, 

349. 

,,     refining  of —see  Oils,  refining. 
,,     relative  price  of,  342. 
,,         ,,    tendency  to  gumming, 

323. 

,,     tests  for  sulphur  in,  123. 
,,     used  for  soapmaking,  408. 
,,     yield  of,  241,  348. 
raps  (rapsamen),  348. 
red  pine  seed  (pine  oil,  pinaster 

oil),  244,  287. 
rosemary,  15. 
rosin — see  Rosin  oils, 
riibsen,  348. 


552 


INDEX. 


Oil,  rue,  3,  14,  20. 
„    safflower  seed,  244. 
„   sanitas,  6,  477. 
„    sapucaja  nuts,  244. 
,,    sardine,  294. 
,,   Scotch  fir  seeds,  244. 
„   seal,  247,  258,  293,  303. 
,,      ,,     relative  price  of,  342. 
,,      ,,     used  for  soapmaking  —  see 

Soapmaking. 
,,   sesame*  (gingelly,  benne",  til  oil), 

244,  286. 
,,         ,,        Baudoin's  sugar  test  for 

— see  Sugar  test. 
„         „        class,  281,  286. 
,,         ,,        detection    of    adultera- 
tions in,  347. 

,,         ,,       relative  price  of,  342. 
„         „        used  for  soapmaking,408. 
„   shark,  shark's  liver,  247, 294, 408. 
„   sheep's  trotter,  52,  286,  298. 
,,    soap  berry — see   Butters,   vege- 
table (soap  berry). 
„    soja  bean,  287. 
,,   sperm,  3,  14,  258,  313. 

adulteration  of,  353. 

as  lubricant,  322-325. 

blown,  320. 

class,  282,  299. 

deposits  spermaceti,  300, 353. 

relative   tendency  to    gum- 
ming, 323. 
,,      ,,  sources,  300,  353. 
,,   spindlenut  (euonymus),  244,  288. 
,,    spirit  (Yorkshire  grease  distilla- 
tion), 277,  278. 
„    sprat,  294. 
„    spring  poppy  seed,  244. 
,,   spruce  fir  seed,  244. 
„    spurge,  244. 
,,   strammonium     seeds  —  see    Oil 

(datura). 

,,   sunflower,  244,  286,  304,  408. 
, ,         , ,       production  in  Russia,  305. 
,,    tacamahac  (tacamahac  fat) — see 

Oil  (calabar  bean). 
„   tallow,  231,  285,  286. 
,,   tamanu,   291  —  see   Oil    (calabar 

bean). 
,,   tansy,  3. 
„   tea  seed,  244,  283. 
,,   thistle  seed,  244. 
„    til — see  Oil  (sesam§). 
„    tobacco  seed,  244,  291. 
,,   touloucoona—  see  Oil(carapanut). 
„   train— see  Oil  (whale). 
,,   tung,  291— see  Oil  (elaeococca). 
„    tunny,  294. 
,,   turpentine,  6,  25. 


Oil,  turpentine,  distilled  off  in  Mei- 

necke's  process,  473. 
,,  ,,     facilitates   air    bleaching 

of  wax,  269,  359. 
,,  ,,     oxidation  of,  477. 

,,          ,,     solvent    for    manganese 

salts  as  driers,  315. 
,,    ungnadia,  244. 
,,    valerian,  15. 
„    valve  (valveoline),  330. 
,,    walnut — see  Oil  (nut). 
„    walrus,  293. 
„   watermelon  seed,  244,  288. 
,,   weld  seed,  244,  291. 
„    whale  (train),  247,  258,  293,  303, 

322. 

„       class,  281,  292,  293. 
,,        ,,       communicates  unpleasant 
smell  to  soft  soap,  459. 
,,         ,,       relative  price  of,  342. 
,,        ,,       used  for  soapmaking — see 

Soapmaking. 
,,  wild  radish  seed,  244. 
,,  wintergreen  (gaultheria),  3,  5, 

14,  19,  192. 
,,   wood  (elaeococca,  Japanese  wood), 

— see  Oil  (elaeococca). 
,,    wool  (from  Yorkshire  grease  dis- 
tillation), 279. 
,,    yellow  horn  poppy,  242. 
,,   zedrach    (margosa,    nimb,    neem 

oil,  veppam  fat),  297. 
Oil  baths  for  tempering  metals,  302, 
Oilcake    parings,    use    in    clarifying 

oils,  255,  256. 
Oilcakes,  114,  211-214,  303-305. 

acrid,  from  mustard  seed,  349. 
composition  of,  213-214. 
cotton  seed,  212,  214,  304. 
dimensions  and  weight  of,  21 1. 
fatty  matters    contained   in, 

115,  213-217. 
free  fatty  acids  contained  in, 

115,  214. 
sunflower,    superior  to  hemp 

and  rape,  305. 
Oil  lamps — see  Lamps. 
Oil  mill  plant,  214-229. 

,,  used  in  olive  oil  pro- 

duction, 200,  343. 
Dils,   absorption  of  oxygen  by — see 

Absorption. 
, ,      acety lation  test  for— see  Acety- 

lation  test. 

„      adulteration  of,  340-361. 
„      animal,  281,  282,  285,  292,  298, 

299,  325. 

,,          ,,       do    not    yield    sativic 
acid,  291. 


INDEX. 


Oils,  anthracene— sec  Anthracene. 
,,      Benedikt  and  Ulzer's  test — see 

Acetylation  test. 
,,      blacktish,  293. 
,,      bleaching  of,  263-268. 
„  ,,  partly   effected    by  pre- 

cipitation of  mucilage, 
&c.,  263 

,,      blown,  4-2,  90,  125,  130. 
,,          ,,    chemical   changes  during 
manufacture  of,  319-321. 
,,          ,,    manufacture  of,  264,  319. 
,,      blubber — see  Oils  (cetacean). 
,,      body  of — see  Viscosity. 
, ,      boiled — see  Oils,  drying  (boiling 

of). 

,,      bone — see  Bone  fat, 
,,      bromine  absorption  of,  176-179. 
,,      burning  (lamp  oils),  2,  5,  302, 

312. 

,,    injurious   effect   of   free 

acid  on,  116,260,313. 

,,      cetacean    (blubber    oils,    train 

oils),  6,   113,  116, 

292,  293,  299,  360. 
,,            ,,           extraction  of,  247. 

,,  from  toothed  whales 

yield     spermaceti, 

293,  300,  301. 

,,  ,,  separation    of    alco- 

holiform  constitu- 
ents from,  121. 

,,  ,,  separation    of    sper- 

maceti from,   300, 
301,  360. 

„      characteristic    oxidation    pro- 
ducts of,  123. 
,,      chemical  changes  during  drying 

of,  134-137. 

,,      clarification    of,    by    chemica] 

processes,  254-263,  349. 

„  ,,    by  filter  presses  and  ordin 

ary  filters,  228, 255, 257 

,,  ,,    by   standing    in   contact 

with  water,  344. 
,,      classification  of — see  Classifica 

tion. 

,,      cleansing  of— see  Oils  (refining) 
,,      coaltar,  2,  5,  50,  328. 
,,      cod,  294— see  Oil  (codfish,  cod 

liver). 
,,      cohesion  figures  of — see  Cohe 

sion  figures. 

„  cold  drawn,  114,  212. 
,,  colour  of— see  Colour. 
}}  ,,  reactions  of — see  Coloui 

reactions. 
,,      congealing  point  of—  see  Melt 
ing  points. 


Oils, 


553 

cooking,  302-304. 
creosote,  2,  328. 
cylinder,  105,  128,  324. 
dead,  324,  328. 
decolorising   of  —  see  Oils, 

bleaching  of. 

dissolved  impurities,  256. 
dolphin,  293. 
drying,  32,  33,  55. 
„  boiling  of,  by  air  blowing 

process,  314-316. 
,,      ,,   by  free   fire  process, 

314,  315. 

,,    by  oxygen  process,321. 
class,  281,  290. 
decolorising  high  class,  268. 
film  test,  Livache'stest,  133. 
present  in  nonxlrying   oils 
in  small   quantity,    185, 
282,  344. 

,,  relative  proportions  of  dif- 
ferent glycerides  in,  136, 
290. 
,,  used  in  paint  manufacture, 

&c.,  313. 
,,         ,,      soft  soapmaking — 

see  Soapmaking. 
drying  of,  chemical  changes  dur- 
ing, 129,  134-137. 
edible,  302-312. 
elaidin  test— see  Elaidin  test, 
effect  of  heat  on,  125-128,  314. 
„       light  on,  130-132,  139, 

149. 
,,       polarised    light  —  see 

Light  (polarised), 
electrical  conductivity  of,  53. 
engine,  324. 
essential,  artificial,  6. 

,,         natural,  2,  5,  20,  53. 
ester  numbers   of — see   Ester 

number, 
examination  of,  general  scheme 

for,  124. 

expression  of,  303— see  Presses, 
extraction  of,  by  solvents,  231- 

244,  303. 
,,         fish  and  liver,  by 

hot  water,  248. 
, ,         vegetable,  fats,  &c. , 
by  hot  water,  200. 
fish,  248,  259,  263,  294,  299. 
,,    bleached  by  hot  air,  264. 
J}  ,,          bichromate,  265. 

, ,     colour  reactions  of,  294. 
,,     detection   in   linseed   oil, 

352. 

,,    give   unpleasant  smell  to 
soft  soap,  459. 


554 


INDEX. 


Oils,  fish,  used  as  adulterants,  348. 
,,       ,,     used  for    soapmaking,  408 

— see  Soapmaking. 
,,      fish  liver,    247,   294,   408— see 

also  Oil  (cod  liver). 
,,      fixed,  2. 
,,      flashing  points  of— see  Flashing 

point. 
,,      free  acid,  number  of — see  Acids 

(free  fatty). 

„      fusel,  C,  14,  20,  53. 
,,      fusing  points  of — see  Melting 

points. 

,,      general  nature  of,  1. 
,,      glyceridic,  3,  93,  281. 
,,  ,,     detected  in  sperm  oil  by 

saponificatiou,  354. 
,,      gumming  of — see  Gumming. 
,,      heat  evolution  with  sulphuric 
acid,  147-151,  341. 
,,  ,,         with  sulphuric  acid, 

effect  of   light  on, 
131,  139. 
,,      Hehner's  test  for — see  Hehner 

number. 

,,      herring,  294. 

, ,      Hiibl's  test — see  Iodine  number, 
,,      hydrocarbon,  2,  5,  54,  90 — see 
also  Oils  (mineral,  paraffin, 
coaltar). 

,,      hydrolysis  of — see  Hydrolysis. 
,,      insoluble  acid,  number  of — see 

Insoluble  acid  number. 
,,      iodine  number  of  (iodine absorp- 
tion of)  —  see  Iodine  number. 
,,      kerosene,  2,  5. 
,,      Koettstorfer's    test — see   Total 

acid  number. 

,,      lamp — see  Oils  (burning). 
,',      lesser  known,  287-289. 
,,  ,,  some      probably 

valuable,  289. 
,,      liver,  294—see;  Oils  (fish  liver, 

shark  liver). 

,,  ,,     colour  reactions  of,  294. 

,,  ,,     contain    cholesterol  and 

biliary  constituents, 292. 
„      lubricating,  2,  5,  67,  321-330. 
,,  ,,         absorption  of  oxygen 

by,  134,  329,  330. 
,,  ,,         analysis  of,  328. 

,,  ,,         characters    and     be- 

haviour of,  325, 326. 
,,  ,,         congelation  of,  67,325. 

„  ,,         flashing    points   of — 

see  Flashing  point. 
,,  ,,         free  mineral  acids  in, 

260,  322  — see  also 
Lubricants. 


Oils,  lubricating,  manufacture  of,  321- 

328. 

,,  ,,         metallic    soaps    con- 

tained in,  121,  324, 
,,  ,,         of   fine  quality  from 

degras,  337. 

,,  ,,         specific  gravity  of, 325. 

,,  ,,         spontaneous   combus- 

tion of,  133. 

,,  ,,         viscosity  of — see  Vis- 

cosity. 

,,  ,,         volatility  of,  325. 

,,      machinery,  128,  324. 
,,      medicinal,  303. 
,,      malabar,  294. 
,,      melting  points  of — see  Melting 

points. 
,,      methyl   iodide,    test  for  —  see 

Methyl  number. 
,,      mineral     (petroleum,     natural 

naphtha),  2,  5,  25. 
,,  ,,      absorption    of     oxygen 

by,  330. 

flashingpointof,126-128. 
lubricants     containing, 

322-330. 

refraction  of,  52. 
relative  price  of,  342. 
specific  gravity  of,  90,91. 
use  of,  in  early  ages  for 

burning,  312. 
,,      viscosity  of,  105. 
nitric  acid   on,   action  of — see 

Nitric  acid  test. 
nitrous  acid  on,  action  of —see 

Elaidin  reaction, 
nondrying,  281. 

,,        usually  contain  small 
quantities  of  drying  oils,  185, 
282,  284,  344. 
nonglyceridic,  3,  93,  282. 
odour  of — see  Odour, 
order  of  price  of,  342. 
oxidation  of — sf  e  Absorption  of 
oxygen,    Oils    (blown),    Oils 
(drying),  Gumming, 
oxidised— see  Oxidised  oils, 
paraffin,  2,  5,  91,  313. 

,,         in  soap,  258 — see  Soap, 

special  kinds  of. 
petroleum — see  Oils  (mineral), 
phosphorised,  from  leguminous 

plants,  123,  259. 
polarised  light,  action  of,  50. 
porpoise,  293. 
proximate  constituents  of,  110- 

124. 

purification   (Noerdlinger's), 
263. 


INDEX. 


555 


Oils,  pyrene,  344. 

,,      rancidity  in— see  Rancid,  Ran- 
cidity. 

,,      ray,  294. 

,,      red — see  Red  oils. 

,,      refining  of,  254-263. 

, ,      refractive  index  of — see  Refrac- 
tive index. 

, ,      Reichert's  test  for— seeReichert 
number. 

, ,       rosin  —  see  Rosin  oils. 

„      salad,  212,  257,  303,  344. 

,,          ,,      refined   cotton    seed   oil 
intermixed  with,  267. 

,,      saponaceous  matters  contained 
in,  121. 

.,      saponifiable,  3,  6,  323. 

,,      saponification   number  of — see 
Total  acid  number. 

,,      saponitication  equivalents  of — 
see  Saponitication  equivalents. 

„      seal,  293. 

,,         ,,     colour  reactions  of,  294. 

„      semidrying,  286,  290. 

.,  ,,         proportions    between 

different  glycerides 
in,  290,  291. 

,,      separation  of  stearines  from — 
see  Stearines. 

„      shale,  2,  5,  90,  91,  313,  322. 

,,      shark  liver,  247,  294,  403. 

„      sod,  336. 

,,      solidifying  points  of — see  Melt- 
ing points. 

, ,      soluble    acid    numbers   of — see 
Soluble  acid  number. 

,,      solubility  in  solvents  of  —  see 
Solubility. 

,,      specific  gravity  of,  76-94,  341. 
,,'     e  fleet  of  light  on,  130. 

,,      spindle,  128,  324. 

, ,      spontaneous  combustion  of,  132. 

,,  ,,  oxidation  of  —  see 

Spontaneous  oxidation. 

,,      standard,    preparation   of — see 
Standard. 

,,      sulphur  chloride  on,  action  of 
— see  Sulphur  chloride. 

,,      sulphocarbon,  344,  408. 

,,      sulphuric  acid  on,  action  of — 
see  Sulphuric  acid. 

,,      sulphurised,  tests  for,  123, 154. 

,,      summer,  257,  304,  348. 

,,      table — see   Oils   (edible,  salad, 
virgin). 

,,      taste  of — see  Taste. 

,,      tournantes — see  Huiles. 

,,      total    acid    numbers    of — see 
Total  acid  number, 


Oils,  train — see  Oils  (cetacean). 
„    class,  281,  292,  293. 
„      Turkey  red,  27,  42. 
,,  ,,     adulterations  of,  334- 

336. 

,,  ,,     analysis  of,  332-336. 

,,  ,,     bibliography  of,  331. 

,,  ,,     constitution   of,    143- 

147,  330,  331. 
,,  ,,     manufacture   of,  330- 

332. 

,,      turret,  324. 
,,      uses  of,  302. 

,,      unsaponifiable      matters     con- 
tained in  —  see    Unsaponifi- 
able matters. 
„      vegetable,     281-285,     286-291, 

295-298. 

,,  ,,  lesser  known,  287. 

,,      virgin,    304,344 — see  also   Oils 

(salad). 

,,      viscosity  of— see  Viscosity. 
„      volatile,  2. 

,,  ,,        acids  from — see  Vola- 

tile acids. 

,,  ,,        number  of — see  Vola- 

tile acid  number. 
,,      vulcanised,  154. 
,,      water  contained  in — see  Water. 
,,      whale,  293 — see  Oils  (cetacean). 
,,          ,,       colour  reactions  of,  294. 
„      winter,  230,  257,  348. 
,,      yield  of,  from  seeds,  &c. — see 

Yield. 

, ,  , ,      fatty  acids  from,  76, 1 63. 

,,      Zeisel's    test    for— see   Methyl 

number. 
,  ,<-     zinc  chloride  on,  action  of — see 

Zinc  chloride. 
Olberg,  water  bath,  61. 
Olefjant  gas,  26. 

Olefines  form  glycols  by  oxidation,  44. 
Olein  (oleic  triglyceride),  7,   11,  28, 

110,  285. 
,,      action  of  nitrous  acid  on — see 

Elaidin  reaction. 
,,  ,,        sulphuric  acid  on — see 

Oils  (Turkey  red). 
Oleine,  candle — see  Red  oils. 

„       cokermit,  90,  92,  231,  283. 
,,       palm  kernel,  283. 
Oleines    (commercial    products),   90, 

92,  110,  285. 
animal,  285,  299. 
distilled,  110,  262,  277,  285, 

324,  377. 

,,  ,,         hydrocarbons    pre- 

sent in — see  Hy- 
drocarbons. 


556 


INDEX. 


Oleines,  from  wool  grease,  276-279. 
,,        Turkey  red  oils,  285. 
,,        vegetable     expressed,     110, 

229,  257,  283. 

Oleine  soaps — see  Soapmaking. 
Oleomargarine — see  Margarine. 
Oleometer,  Lefebre's,  79. 
Oleonaphtha,  330. 
Oleorefractorneter,  51-53,  347. 
Oleostearine,  93. 
Olive  stearine,  230. 
Olive    trees,    different    species    and 

varieties  of,  342. 
Opderbeck,  oxygen  process,  321. 
Open  test  (flashing  point),  126. 
Oudemauns,  Kambutan  tallow,  296. 

,,  stearidic  acid,  30. 

Overbeck,  oxidation  of  stearolic  acid, 

36,  45. 

,,          oxyoleic  acid,  41. 
Ox  tallow — -see  Tallow. 
Ox,  utilisation  of  fat  of  an,  311. 
Oxalic  acid  from  glycerol,  8,  519-522. 
,,      acids  from  glycols   by  fusion 

with  potash,  18. 
Oxidation  during  boiling,  125. 
of  aldehydes,  20,  25. 
,,         of  fatty  acids  during  dry- 
ing, 113. 
of  oils  by  light,   130-132, 

139,  149. 

,,         of  oils  during  drying,  42, 
129-137 — see  Absorption 
of  oxygen,  Gumming. 
,,         products  of  fatty  acids,  19, 
33/36,  40,  43. 
,,  ,,  characteristic, 

128,  129. 

,,         spontaneous  —  see     Spon- 
taneous oxidation. 

Oxidised  oils  (oils  naturally  contain- 
ing oxygen),  3. 
,,  (commercial;  really  are 

sulphurised),  154. 
,,  (linseed     "skins"     for 

linoleum),  318. 

, ,  (oils  treated  with  oxidis- 

ing materials),  42 — 
see  al*o  Oils  (blown, 
and  refining  of). 

Oxy acids  formed  during  drying,  135. 
Oxygen,   absorption  of — see  Absorp- 
tion. 
,,         addition  to  "  unsaturated  " 

acids,  33,  36,  45. 
Oxyoleates,  42,  332. 
Oxyoleic  acid,  41. 

,,        mixed  glyceride,  144. 
Oxyolein,  139. 


Oxystearic  mixed  glyceride,  144. 

Ozokerite    (solid   mineral   hydrocar- 
bons, earthwax),  2,  5,  6,  88, 
91,  364 — see  also  Cerasin. 
,,     used  as  beeswax  adulterant, 
359. 


Paint,  135,  302. 
Palmer,  metallic  wick,  394. 
Palmieri,  electrical  conductivity,  53. 
Palmitin  (palmitic  triglyceride),  11, 

285. 
,,         chief   solid   constituent  of 

olive  oil,  344. 
Palmitine  (commercial  product),  387, 

407 — see  also  Candle  stearine. 
Pans  for  boiling  oil,   soap,   &c. — see 
Kettles,    Decomposing    pan, 
Cooling  pan,  lie-melting  pan, 
Crystallising  pan,  &c. 
,,     crutching  soap,  438-442. 
Paracholesterol,  18. 
Paraffin  wax — see  Wax  (paraffin). 
Paraphytosterol,  16,  17. 
Paring  machine  (oilcake),  223. 
Parings,   edge  runners  for  grinding, 

220,  223. 

Paris  Municipal  Laboratory,  65,  82. 
Parnell,  causticising  under  pressure, 

413. 

Paterson,  spectrum  colorimeter,  50. 
Payne,  glycerine  manufacture,  515. 
,,       melting    points    of    distilled 

fatty  acids,  384. 
Pea  nut — see  Oil,  arachis. 
Pearlash,  409. 
Pearlashing,  451,  479,  489. 
Peh-la— see  Wax,  Chinese. 
Pelargonium,  20. 

Pendulum  machine,  M'Xaught's,  94. 
Pensky,  flashing  point  apparatus,  127. 
Perfumes,  injurious  effects  of  excess 

of,  in  toilet  soap,  480. 
,,          oils  used  in  extraction  of, 

302,  479. 

,,          used   for  soap— see   Soap- 
making  (perfuming). 
Permanganate,  oxidation  by,  charac- 
teristic   pro- 
ducts  of,    128, 
129. 
,,  ,,  of  acrylic  acids, 

28,  30,  41-44. 

,,  ,,  of  animal  oils  does 

notformsativic 
acid,  291. 

,,  of  linolenic  acid, 
37,  43,  128. 


INDEX. 


557 


Permanganate,  oxidation  of  linolic  acid 

34,  35,  43,  128. 

,,  ,,  of  ricinoleic  acid, 

40,  43,  129. 
,,  ,,  of  stearolic  acids, 

33,  36,  45. 
,,  ,,  rule    respecting, 

44. 
,,  wax      bleached      by 

means  of,  269. 
Peroxide    of  hydrogen  as  bleaching 

agent — see  Hydrogen  peroxide. 
Peters,  linolic  acid,  34. 

,,      polarised  light,  51. 
Petroleum — see  Oil  (mineral). 

,,       ether  (light  petroleum  spirit, 

benzoline),  2,  5. 

,,  ,,  as  solvent,  55,  115,  118- 
124,  231,  236,  252, 
262,  273,  275,  328, 
329,  336, 337— see  also 
Soap  analysis. 
,,  ,,  fatty  acids  insoluble  in, 

from  boiled  oil,  135. 
,,  ,,     preferable  to  ordinary 

ether  as  solvent,  118, 
120,  273,  275. 
Phasol,  16,  259. 
Pheasant  grease,  298. 
Phenol  (carbolic  acid)  and  homologues, 

3,  6,  15,  16,  53. 

,,      determination  of,  in  soap,  506. 
,,      extraction  from  coaltar,  230. 
,,      use  of,   in  disinfectant  soaps 
— see  Soaps,  special  kinds  of 
(carbolic,  disinfectant). 
Phenolphthalein  as  indicator,  23, 115- 

117,  124,  328,  333,  359,  497. 
Phlorol,  16. 

Phosphorised  constituents,  121. 
Phosphorus,  determination  of,  124. 
Physical  properties  of  glycerol,  7. 

„  ,,  oils,  &c.,  47-109. 

Phytosterol,  6,  16,  17,  240,  259. 

, ,  determination  of  inoils,  &c.,121. 
Pichurim  bean  fat,  20. 
Pickling  soap  bars,  438. 

,,        wicks,  394,  395. 
Pigments  (mottled  soap),  472. 
Piston  candlemoulding  machines,  399, 
Pitch,  Burgundy,  adulterant  of  bees- 
wax, 359. 

Pitch  formed  in  Wilson's  process,  381, 
,,     from    distillation   of    foots   by 
superheated  steam 
261. 

,,  ,,     of  Yorkshire  grease 

by        superheated 
•  steam,  277. 


'itchused  as  coarse lubricant,277,324. 
:*liny,    early  soapmaking  processes, 

449. 

'lotting  (milled  soap),  448. 
^lumbago  (antifriction),  324. 
3ohl,  melting  points,  64. 
oiseuille,  viscosity,  107. 
5olariscope,     polarised     light  —  see 

Light,  polarised. 
Dolishing  candles,  406. 

,.         soap  tablets,  448. 
^olyglycerols,  8. 
Polymerised  fatty   acids  formed  by 

elaidin  reaction,  139. 
, ,  glycerides  formed  during 

boiling    and    drying, 
135,  318. 

,,  oleo-oxystearic  acid,  330. 

,,  ricinoleic  acids  —  see 

Acid,  ricinoleic. 
Pomades,  lanolin  used  in  making,  339. 

,,         oils  used  in  making,  302. 
Porpoise  blubber,   extraction  of  oil 

from,  247. 
Potassium  carbonate,  causticising— see 

Causticising. 
,,  ,,         leys,    alkalinity 

of,  419. 

,,  ,,         used     in    Mege 

Mouries      pro- 
cess, 308. 

,,  .,         used    in    pearl- 

ashing  —  see 
Pear-lashing. 

,,  ,,         used     in     soap- 

making —  see 
Soapmaking. 

,,         chloride,   action    on    soda 

soaps,  490,  491. 

,,  ,,         source  of  potash, 

410. 
Potash,  action  on  brominated  acids, 

28. 

,,  caustic  (potassium  hydroxide), 
effect  of  fusion  with — see 
Hydrogen. 

,,      from  sunflower  seeds,  305. 
„      leys,  alkalinity  of,  417,  419, 

420. 

,,      leys,  preparation  of,  411-414. 

,,      neutralised  —  see    Free    acid 

number,  Total  acid  number, 

&c. 

,,      quantity  equivalent  to  soda, 

425. 

„    to  fats  — see 
Calculations. 

,,  soaps,  action  of  soda  salts  on, 
451,  472,  473. 


558 


INDEX. 


Potash,  use  of,  in  refining  oils,256,261. 

,,      vegetable  alkali,  409. 
Potato  fusel  oils,  14. 
Poullain  and    Michaud,   zinc    oxide 

process,  379,  515. 

Poutet,  elaidin  reaction — seeElaidin. 
Power  requisite  in  oil  mill,  215-217. 
Precipitation     processes      (removing 

mucilage,  &c.),  255,  262,  263. 
Press  cake — see  Cold  press  cake,  Hot 

press  cake,  Separation  cake. 
Presses,  cold — see  Cold  press, 
earlier  forms  of,  199. 
elbow,  2U2. 
hot — see  Hot  press, 
hydraulic,  207,  343. 
pressure  requisite  in,  211. 
screw,  205,  343. 
wedge,  203. 
Pressure,    distillation    under   dimin- 
ished— see  Distillation. 
„         in  autoclaves,  373. 
,,         in  oil  presses,  211. 
,,         rendering  tallow  under  in- 
creased, 250. 

,,         soapmaking      under       in- 
creased, 462-464. 
Prices  of  oils,  &c.,  342. 
Primrose  soaps,  474,  509,  510. 
Printing  ink,  125,  317,  318. 
Proximate  constituents,  110-124. 

,,  ,,    information  wanted 

concerning,  113. 
,,  ,,    separation  of,    111- 

113. 

,,  ,,    variation  with  soil, 

climate,  &c.,  111. 
Pumps,  soap,  434. 
Pulfrich,  refractometer,  51. 
Purvis,  waggon  grease,  327. 
Pyknometer,  77. 

Pyramid    drainage    surface    (filter- 
press),  229. 
„         night  lights,  406. 

Q 

QUANTITATIVE  reactions  of  oils,  &c., 

156-198. 
„  tests  for  oils,  tabulated, 

194-198. 
Quantity    of     alkali     requisite     for 

saponification — see  Calculations. 
Quebrachol,  16. 
Quicklime— -see  Lime. 
Quinquet,  use  of  lamp  chimneys,  313. 


EADISSON,  palmitic  acid  process,  387. 


Railway  grease— see  Lubricants. 
Rancid    tallow,    &c.,    cleansing    of, 

256,  260,  261,  265,  310. 
Rancidity,  10,  49,  69,  255. 

,,          due  to  oxidation,  132. 
,,          light  promotes,  132. 
,,          produces  much  free  fatty 
acid,  10,  114,  255,  355. 
Rape  seed  (colza,  cole  seed),  various 

species  of,  348. 
Raphigaster,  25. 
Rational  Beaume  scale,  86. 
Raw  oils,  313— see  Oils  (drying). 
Reaction,  specific  temperature,  149. 
Reactions  of  oils,  &c.,  quantitative, 

156-198. 

Reaumur  scale,  57,  58. 
Recovered  greases— .see  Grease. 
Red   oils    (crude   oleic    acid,    candle 

oleine),  110,  231,  285. 
analysis  of,  375,  378. 
expression  of,  231,  370. 
filter  cake— see  Filter  cake, 
palmitic  acid  from,  387. 
soap  from — see  Soapmaking 
unsaponified  grease  in — see 

Unsaponified  fat. 
,,         utilisation  of,  386-388. 
,,         yield  from  ox  fat,  311,  312. 
Redwood,  viscosimeter,  98. 

,,  ,,      results  obtained 

by,  101-105. 
Refining  oils,  &c.,  254-263. 

,,  acid  processes,  259,  349. 

„  alkaline     „      260,  349. 

,,  ,,    process  removes  free 

acids,  12,  115,  260,  322. 
, ,  by  treatment  with  water,  344 
,,  Hartley    and    Blenkinsop's- 

process,  263. 

,,  Noerdlinger's  process,  263» 
, ,  precipitation  processes,  262. 
,,       virgin  oils,  304. 
Reformatsky,  linolic  acid,  34,  35. 
Refractive   index,  refractometer,  51 ,. 

341. 
Reichert's  test  (Reichert  number),  23, 

53,  157,  195,  341. 
,,          mode  of  working,  173-176. 
Reichert-Meissl  test,  174,  195. 
Reichert- Wollny    „    175. 
Reichl,  test  for  glycerol,  8,  516. 
Reimer  and  Will,  dierucin,  11. 

,,  rapic  acid,  41. 

Relative  density — see  Specific  gravity. 

,,        viscosity — see  Viscosity. 
Remelting  pans,  441-443. 
Renard,  test  for  arachis  oil,  344. 
Rendering  animal  fats,  245.-251. 


INDEX. 


559 


4tf    S 


Resin  (pine)— see  Rosin. 

,,      used  for  early  torches,  312. 
Resinate  of  soda,  450,  453. 

, ,  calculations  respect- 

ing, 455,  465. 

,,  useofjinsoapmaking 

— see  Soapmaking ; 
Soap,  special  kinds 
(yellow  soap). 
Resinous  constituents  of  oils,  118. 

,,  ,,        removal  of,  from 

oils,    255,    256, 
260,  262,  322. 
Resins  and  resinoid  bodies,  3,  25. 

,,  ,,      used  as  beeswax 

adulterants,  359. 

Richards,   testing  liability   to   spon- 
taneous inflammability,  133. 
Richardson   and    Watts,    railway 

grease,  327. 

Richmond,  density  of  glycerol  solu- 
tion, 517. 

Ricinelaidin,  40,  137. 
Ricinolein  (ricinoleic  triglyceride), 
,,    action  of  nitrous  acid  on,  137. 
,,    distillation  of,  40. 
Rideal,   viscosity  of  gum   solutions, 

108. 
Ritsert,  causes  of  rancidity,  132. 

,,        glycerine  testing,  515. 
Rock— see  Candle  stearine. 
Rolls — see  Crushing  rolls. 
Rose,  Down  and  Thompson,  oil  press 

machinery,  215. 

Rosin,  (colophony),  88,  92,  118,  178. 
,,      action  of  sulphur  chloride  on, 

156. 
.,      admixed  with  thickened  oils, 

&c.,  142. 
,,      adulteration    of    linseed     oil 

with,  352. 

,,          ,,     of  beeswax  with,  359. 
,,      manufacture    of    resinate    of 

soda,  453. 
,,      use    in     making    lubricating 

greases,  327-329. 

„          ,,       soapmaking — see  Soap- 
making. 

,,      window  glass,  474. 
Rosin  oils,  2,  92. 

,,        ,,     absorption  of  oxygen  by, 

330. 
,,        ,,     action    of,    on    polarised 

light,  50. 
,,        ,,     adulteration    of    linseed 

oil  with,  352. 
,,        ,,     detection  of,  in   Turkey 

red  oils,  335. 
,,        „     fluorescence  of,  50. 


Rosin  oils,  refractive  index  of,  52. 

,,        ,,     relative  price  of,  342. 

,,         ,,     solubility  in  glacial  acetic 
acid,  55,  57,  329. 

, ,        , ,     use  of,  in  preparing  lubri- 
cants, 322-324,  327-329. 

,,        ,,     viscosity  of,  105. 
Rotation  of  polarised  light — see  Light 

(polarised). 
Roy  an,    candle    moulding   machine, 

398. 

Riidorff,  melting  points,  69. 
Rule  followed  in  oxidation,  44. 
Rush  lights,  rush  pith  wicks,  312, 362r 

390. 

Russian  mineral  oils  (viscosity),  105. 
Rutschmann,  stripping  machine,  446. 


SAKE,  grease  recovery,  272. 
Salad  oils— see  Oils  (salad), 
alt  as  source  of  alkali  (soda),  410. 
,,    in  butter,  &c.,  123,  307. 
Salting  out,  23,  33,  54. 

,,  in  refining  oils,  &c.,  256. 

,,  in  soapboiling — see  Soap- 

making. 

,,  in  Turkey  red  oil  mak- 

ing, 331. 

Sand,  use  of,  in  clarifying  oils,  255. 
Sanza  (olive  marc),  343. 
Saponaceous  matters  in  oils,  &c.,  121- 

124,  135,  315,  324,  328,  347. 
Saponitication  by  alkaline  carbonates,. 

409,  410. 
Saponification  equivalents,    33,   158, 

194,  341. 
,,  ,,     determination  of  r 

161-170. 

,,  ,,     of  glycerides  ex- 

ceed mean  equi- 
valents of  acids 
by  12-67,  165. 

,,  in  three  stages,  468. 

, ,  number— see  Total  acid: 

number. 

,,  quantity  of  ley  requisite- 

for — see  Calculations. 

Saponification,   typical  reactions  of,. 

3-5. 

Saponin,  297. 

Sarg,  utilisation  of  fat  of  an  ox,  311. 
Saturated  hydrocarbons — see  Hydro- 
carbons. 

Saturation,  fractional,  112,  113. 
Saytzeff,  dioxystearic  acids,  28,  30, 
41,  42,  46,  129. 


560 


INDEX. 


Saytzeff,  oxystearic  acids,  38,  39. 
, ,          use  of  mercuric  bromide  in 

Hiibl's  test,  179. 
Scales,  hydrometer,  84-86. 
,,       thermometer,  57-60. 
Schadler,  amounts  of  fatty  matter  in 

seeds,  &c,  241-244. 
,,     cohesion  figures,  49. 
,,     colour  reactions,  154,  294. 
,,     distillation  with  superheated 

steam,  383. 

,,     hydrometer  scales,  85. 
,,     iodine  numbers,  182. 
,,     melting  points,  67-70. 
,,     nonexistence  of  doeglic  acid, 

24. 

,,     polarised  light,  50. 
, ,     Reichert-Meissl  numbers,  1 74 
,,     Roy  an's     candle     moulding 

machine,  398. 
,,     solubilities,  54,  55. 
,,     specific  gravities,  87. 
,,     total  acid  numbers,  160. 
,,     unsaponifiable  matters,  257. 
,,     yield  of  linseed  oil,  351. 
,,  ,,     rape  seed  oils,  348. 

Schepperand  Geitel,  melting  points.  76 
,,          separation  cake,  376. 
Scheme  for  examination  of  oils,  124. 

, ,  , ,  soaps,  506. 

Scheurer  Kestner,  Turkey   red  oils, 

146,  333. 

Schlink,  deodorising  cokernut  oil,310. 
Schmid,  viscosimeter,  95. 
Schmidt's  process  (zinc  chloride  and 

oleic  acid),  142,  386. 
Schmitz  and  Toenges,  oxyoleates,  332, 
Schnaible,  toluene  as  solvent  for  wax 

in  soap,  496. 

Schfin,  hypogseic  acid,  24. 
Schroder,  oxyhypogseic  acid,  41. 
,,         palmitoxylic  acid,  45. 
,,         — see  Grills  and  Schroder. 
Schiibler,  viscosimeter,  95. 

„      results  with,  102. 
Schuler,  linoleic  acid,  33. 
Scotch  mineral  oils,  viscosity  of,  105. 
Scourtins  (oil  extraction),  204. 
Scraps  from  ox  fat,  311. 
Screens  for  sifting  seeds,  &c.,  223. 
Screw  presses,  205-207. 
Scribe  for  marking  soap  blocks,  437. 
Seal  blubber,  extraction  of  oil  f  rom,247 
Sealing  wax,  302. 

Sea  weed  jelly  (antifriction),  324,  328. 
Seed  crushing — see  Oil  mill  plant,  anc 

Crushing  rolls. 

Seeding  (of  press  cake) — see  Separa 
tion  cake. 


seeds,  determination  of  fat  in,  237. 
, ,      yield  of  fatty  matter  from,  241- 

244. 

eibel,  sulphurised  lanolin,  339. 
teltsam,  bone  fat  extraction  process, 

253,  254. 

Separation  of  fatty  acids,  112,  113. 
,,  proximate  constituents, 

111. 

Separation   cake,   (press  cake),  311. 
,,  analysis  of ,  375, 378. 

,,  seeding       (granula- 

tion,   crystallisa- 
tion) of,  355,  367- 
'Shale  oils — see  Oils  (shale). 
Shark  livers,  extraction  of  oils  from, 

247. 

Shaving  cream.  483. 
Shea  butter — see  Butters,  vegetable 

(Shea). 
Qheep's  tallow— see  Tallow. 

hoddy  scourings,  grease  from,  276. 
Silver,  bromostearate,  action  of  water 

on,  25,  30. 
,,  hydroxide,    action    on  bromin- 

ated  acids,  &c.,  27, 30, 41,  43. 
,,  nitrate  test,  152-154. 
,,  test(Becchi's) — seeBecchi's  test. 
Skalweit,  density  of  glycerine  solu- 
tion, 516,  517. 

Singer  and  Judell,  wool  scouring,  337. 
Skimmer  pipe  (soap  kettle),  433,  434. 
Skins  from  drying  oils,  135,  381. 
, ,      tanning  and  currying,  302,  336. 
,      tender,    injurious     effects     of 
alkaline,    highly    perfumed, 
and   sugared  soaps    on — see 
Soap,  alkaline  ;  Soap,  special 
kinds  of  (transparent;  highly 
scented). 
Slabbing  soap,  437,  438,  444. 
Smith,  Watson,  wool  scouring,  337. 
Soap,  alkaline,  calculations  respecting 
excess  of  alkali  in,  454,  464. 
,,       ,,     degree  of  alkalinity  judged 

by  tongue,  510. 

,,       ,,     injurious  effects  of,  on  ten- 
der skins,  458,  479. 
,,       ,,          ,,     on  wool,    silk,  &c.,. 

453,  461. 
Soap  analysis — 

Cailletet's  method,  507,  508. 
Calcium  salt  test,  508. 
Classification  of  toilet  soaps,  512. 
Determination  of  actual  soap,  492, 

493. 

,,  ,,      calcula- 

tion respecting,  493. 
„        of  alcohol,  505,  506. 


INDEX. 


561 


Soap  analysis — 

Determination  of  average  molecular 
weight  of  fatty  acids, 
172,  494. 
,,     crude   fatty   acids,  492, 

493,  496,  506. 
„     fatty  anhydrides,  493,496, 

497,  50(5. 
,,     free  alkali,  492,  497-501, 

507,  512. 
,,         ,,  as  caustic,  498-500, 

507. 

,,  ,,  ascarbonate,500,507. 
,,  ,,  by  alcohol  test,  498. 
,,  ,,  by  fatty  acid  titra- 

tion  test,  499. 
.,,         ,,  by  salting  out  test, 

500. 

,,  »,  by  salting  out  test, 
excess  found  by, 
500. 

,,     glycerol  494, 504-506, 512. 
,,     hydrocarbons     (paraffin, 
&c.),  258,  495,  496,506. 
,,     mineral    weighting    ad- 
mixtures  (China   clay, 
steatite,  &c.),  494,  504, 
507. 

.,,     organic  weigh  ting  admix- 
tures (starch,  oatmeal, 
sawdust,      &c.),      494, 
504,  507. 
,,     phenol    and    phenoloids, 

506. 

,,     pigments,  504. 
„     potash,  501,  506. 
, ,     rosin  acids,  474,  497, 506, 

508. 

.,,  ,,  by  Gladding's  pro- 

cess, 485, 501, 
502,  511. 

,,          ,,        ,,  sources  of  er- 
ror in,  502. 

,,          ,,  by  modified  Glad- 
ding's  process,  502. 
.,,          ,,  bv  Twitchell's  pro- 
cess, 503,  504,  511. 
.,,     salts  (sulphates,chlorides, 
&c.),  494, 497,  499,  506, 
507. 

, ,  silicate,  494, 497,  504, 507- 
„  soluble  acids,  496,  497, 

499 

„     sugar,  494,  504-506. 
, ,     total  alkali,  492, 493, 496, 

497,  506. 

,,  unsaponifiable  matters 
119,  258,  492-495,  497, 
506. 


Soap  analysis — 
Determination  of  unsaponified  fat, 

492,  495-497,  506. 
,,     volatile  matters,  505. 
„     water,  494,  495,  506. 
,,     waxy  matters  (beeswax, 
spermaceti,  cholesterol, 
&c.),  495,  496,506. 
General  schemes,  494,  506,  507. 
Typical    results    (  manufacturers', 
pharmaceutical,  toilet,  soft  soaps, 
&c.),  508,511. 
Soap,  bleaching  dark  coloured,  267. 

chemistry  of,  484-492. 
Soap  factory  plant,  426-448. 
Crutchincr  pans,  438-441. 
Curbs,  432,  433. 
Cutting  appliances,  437,  438. 
Fan,  433,  434,  460. 
Frames,  434-437,  444. 
Kettles  (coppers,   pans) — see  Ket- 
tles. 

Milling  machinery,  446. 
Plotting  machinery,  448. 
Pumps,  434. 

Remelting  pans,  441-443. 
Slabbing    and    barring    machines, 

437,  438. 

Stamping  machines,  444,  445. 
Steam  twirl,  428 — see  also  Morfit. 
Stripping  machine,  446. 
Soap,  fused,  reaction  of  salts,  &c. ,  on, 

451,  473,  488-492. 
,,  ,,     alkaline     carbonates 

on,  451,  489,  490— 
see  also  Pearlashing. 
historical  references  to,  449. 
hydrolysis  of,  486-488. 

,,    Wright  and  Thompson's 

experiments,  487. 
leaves,  483. 
powders,  477. 
saline  matters   in,    calculations 

respecting,  455,  465. 
Soap,  special  kinds  of — 
Aluminated,  451,  475. 
Bleached  palm  oil,  508. 
Borax,  451,  475. 
Castile,  467,  472,  508. 
Carbolic,  451,  477. 
Carbonated,  451,  462,  475,  477— 

see  also  Pearlashing. 
Cold  water,  477,  509,  510. 
Curd — see  Soapmaking. 
,,  amount   of   water  present  in, 

470. 

,,  analysis  of,  508,  510. 
Dealkalised  (neutralised),  453,  461, 
480,  481,  483,  484. 

36 


562 


INDEX. 


Soap,  special  kinds  of— 

Disinfectant  (  carbolic,  cresylic, 
naphthol,  sanitas,  terebene,  &c.), 
451,  476,  477. 

Emollient  (containing  lanolin,  sper- 
maceti, vaseline,  wax,  &c. ),  448, 
478,  479. 

Fancy — see  infra  (Toilet). 

Filled— see  Soapmaking  (tilling). 

Fitted — see  Soapmaking  (fitting). 
,,  amount  of  waterpresentin,  470. 

Floating,  441. 

Glycerine,  458. 

,,          containing      additional 
glycerol,  458,  479,  482,  512,  513. 

Harlequin,  483. 

Highly  scented,  injurious  action  of, 
480,  512. 

Ivory,  509. 

Little  pan,  479. 

Marbled,  483. 

Marine — see  Soapmaking. 
,,       analysis  of,  508,  509. 

Marseilles,  407,  472,  508,  509. 

Medicinal  (creosote,  cresylic,  ich- 
thyol,  iodine,  mercurial,  naph- 
thol, sanitas,  sulphur,  terebene, 
&c.),  477. 

Metallic—  see  Metallic  soaps. 

Milled,  446-448,  457,  479,  480,  511. 

Mottled — see  Soapmaking. 

,,         amount  of  water  present 
in,  472. 

Neutralised  —  see  supra  (Dealka- 
lised). 

Normandy,  475. 

Oil  (red  oil,  oleine) — see  Soap- 
making. 

Old  brown  Windsor,  480. 

,,  ,,         modern  inferior 

kinds  of,  481. 

Oleine — see  Soapmaking. 
,,       analysis  of,  509,  510. 
,,       contains  hydrocarbons,  258, 
279,  496. 

Olive,  467,  472,  508. 

Paraffin  and  petroleum,  458,  476. 

Perfumers',  450,  456,  479. 

Pharmaceutical,  510. 

Phpsphated,  476. 

Primrose — see  infra  Rosin  soap. 

Remelted  and  blended  toilet,  441, 
478. 

Rosin  (yellow),  450,  451,  453,  473, 

474,  509. 
,,       calculations  respecting,  455, 

465. 

„       French  process,  473. 
„       primrose,  474,  509,  510. 


Soap,  special  kinds  of — 

Rosin,  primrose,  analyses  of,  509, 

510. 

Sand    (brickdust,    emery,    fullers' 
earth,  kaolin,  pipeclay,  pumice- 
stone,  &c.),  476. 
Shaving  cream,  483. 
Silicated,  451,  453,  462,  472,  474, 

475. 
,,         calculations    respecting, 

455,  4(55. 

,,         objectionable    for    wool 
scouring   and   laundry 
purposes,  461,  475. 
,,         wastes  less  rapidly,  475. 
Soft— see  Soapmaking. 
Starch    (oatmeal,    bran,  cornflour, 
dextrine,  gluten,  Iceland   moss, 
sawdust,  &c. ),  477. 
Sugared— see  infra  Transparent. 
Sulphated,  451,  475. 
Superfatted,  478,  479. 
Toilet  (fancy),  409,  441,  478-480. 
,,  analyses  of,  511. 

,,  classification  of,  512. 

Tooth,  476. 
Transparent,  cold  process,  450, 458, 

476,  482. 

,,  -  ,,     analysis  of,  511. 

,,  ,,     calculations      re- 

specting,   465. 

,,  ,,     injurious     effects 

on  tender  skins, 

458,    459,     480, 

482,  512. 

,,  ,,     sugared,  458,  480, 

482,  511,  512. 

,,  ,,     transparency    in- 

creased by  alco- 
hol,   glycerol, 
sugar,  458,  481. 
,,         spirit  process,  445,  446, 

458,  474,  482. 

,,  ,,     analyses  of,  511. 

,,  ,,     distillation       of 

spirit,  446,  482. 
White  Windsor,  481. 
Wool  scouring,  458. 
Soap,  water  in,  calculations,  respect- 
ing, 454,  464. 

,,  „     determination     of  —  see 

Soap  analysis  (water). 
Soapmaking,    classification    of    pro- 
cesses —  direct     neutralisa- 
tion, 450-456. 
,,       glycerides  used  and   glycerol 

retained,  450,  456-466. 
,,       glycerides  used  and   glycerol 
eliminated,  451,  466-473. 


INDEX. 


563 


Soapmaking,  factory  operations — 
Cleansing  curd,  467. 
Crutching,  438-440,  441. 
Cutting,  slabbing,  and  barring,  437, 

438,  444,  449. 
Dealkalising  —  see     Soap,     special 

kinds  of  (dealkalised). 
Drying,  438,  447. 
Filling  (loading),  438,450,  458,  462, 

465,  472,  476,  483,  511. 
Fitting,  451,  467,  470,  471. 
Framing,  434-437,  444,  449. 
Graining  (cutting  the  soap  ;  salting 
out),   54,   413,    433,    450,    469, 
485. 
Killing — see  infra  Manufacture  of 

curd. 

Loading — see  supra  Filling. 
Manufacture  by  cold  process,  450, 
457,  513 

,,  ,,    calculations 

respecting,  464-466. 

,,     by  old    German   process, 

449,  451,  472,  473. 
,,     of  curd  soap,  boiling  for 
curd,  451,  467-470. 
,,  ,,      analysis    of    curd 

soap,  508,  510. 
,,     of  fitted  soaps — see  supra 

Fitting. 
,,     of    hydrated    soap,    450, 

456,  461. 
,,         ,,     (Swiss    soap,  Esch- 

wegeSeife),461. 
,,         ,,     under  pressure,  450, 

456,  461. 
,,     of  marine  soap,  450,  456, 

461,  508,  509. 
,,     of  milled  soap — see  infra 

Milling. 
,,     of  mottled  soap,  451,  466, 

471,  472,  509. 

,,  ,,       modern      inferior 

kinds,  467,  472. 

,,     of  oleine  soap  (oil  soap), 

258,451-453. 

,,         „    analyses  of,  509,  510. 
,,         ,,    calculations  respect- 
ing, 454-456. 

,,     of  resinate  of  soda,  453. 
,,     of    soft    soap,    450,    456, 

459,  466. 

,,  ,,       analyses  of,  510. 

,,  of  transparent  soap — see 
Soap,  special  kinds  of 
(transparent). 

,,  of  yellow  soap  (rosin  soap) 
— see  Soap,  special 
kinds  of  (rosin). 


Soapmaking,  factory  operations — 
Milling,  446,  457,  479,  480. 
Pearlashing,  451,  479,  489. 
Perfuming  (scenting),  441,444,448, 

457,  478-480,  483,  512. 
Pickling  bars,  438. 
Plotting,  448. 

Preparation  of  leys,  411-426 — see 
also  Alkali,  Alkalinity,  Caus- 

ticising,  Potash,  Soda. 
,,      calculation  of   quantity  re- 
quisite for  saponification, 
421-426. 

Kernel  ting,  441-443,  478. 
Running  off  spent  leys,  428,   432, 

433,  469. 

Salting  out — see  supra  Graining. 
Slabbing  and  barring,  437,  444,  449. 
Stamping  tablets,  444,  445,  449. 
Stripping,  446. 
Tinting,  441,  479. 
Soapmaking,  raw  materials  for,  302, 

408-411. 
Soaps,  colonial,  509. 

,,       commercial     (manufacturer's, 

laundry,  &c.),  composition 

of,  by  analysis,  508-510. 

, ,       discoloration  of,  266,  356,  479. 

,,       discoloured,  bleaching  of,  267. 

,,       ingredients    in    lubricating 

'  mixtures,  324-329. 
,,       jellifying  of,  485. 
,,       manufacturers  —  see     Soaps, 

commercial. 

,,       metallic— see  Metallic  soaps. 
, ,       mixed,  formed  from  mixture  of 
acids  and  excess  of  alkali,  491. 
,,       salting     out     from     solution 
(Whitelaw) — see  Soapmak- 
ing (graining),  486. 
,,       solubility  in  water,  &c.,  485. 
,,       toilet,  classification  of,  accord- 
ing to  free  alkali,  512. 
,,          ,,       composition    of,    by 

analysis,  511. 
Soapsuds,  recovery  of  grease  from — 

see  Grease. 
Soap  test,  Clark's  (water  hardness), 

485,  508. 
Soda  ash,  410. 
„      ,,     causticising  —  see    Causti- 

cising. 

,,     caustic  (sodium  hydroxide),410. 

„  „     colour  test,  151,  153,352. 

,,  ,,     effect    of    fusion    with 

(soda   lime)  —  see 

Hydrogen. 

,,  ,,     leys,  alkalinity  of,  414- 

416,  419,  420. 


564 


INDEX. 


Soda,   caustic  leys,  employment  in 
soap  boiling — see 
Soapmaking. 
,,  ,,       ,,     preparation  of,  411- 

414. 

,,  ,,       ,,     quantity      equiva- 

lent to  fats — see 
Calculations. 

,,  ,,       ,,     storage  of,  412. 

,,  ,,       ,,     variation  of  density 

of,  with  tempera- 
ture, 416. 

,,  ,,     manufacture  of,  410. 

,,  ,,     use  in  making  waggon 

grease,  327. 

,,  ,,      „  refining  oils,  260, 261. 

,,      crystals,  fused,  use  in  oil  re- 
fining, 260. 

,,      degrees — see  Degrees. 
,,      quantity  equivalent  to  potash, 

425. 
,,       trade,   British    custom    as  to 

alkalinity,  420. 
Sodium  carbonate,  action  on  potash 

soaps,  488-490. 
,,       as  lard  adulterant,  306. 
, ,       direct  use  in  soapmaking, 

409,  433,  453,  463. 
„       leys,    alkalinity  of,   418 
— see  also  Caustic  soda. 
,,       use   in  making  waggon 

grease,  327. 
,,       use  in  refining  oils,  256, 

261. 
Sodium  chloride,    action    on    potash 

soaps,  451,  473,  490. 
,,     silicate,  manufacture  of,  463. 
,,     sulphate,  Leblanc  process,  410. 
,,         ,,     used  in  refining  oils,  256. 
Soft  soap — see  Soapmaking. 
Softening  point,  61. 
Solar  stearine — see  Stearine  (lard). 
Solutions  for  chilling  baths,  67. 
Solid  adulterants  of  fats,  &c.,  123. 
Solidification    points  —  see    Melting 

points. 

Soluble  acid  number,  168,  195. 
Solubility  of  blown  oils,  320. 

of  fatty  acids  in  alcohol,  '23. 
, ,         in  water,  23. 
of  lead  salts  in  ether — see 

Ether. 

of  oils,  &c.,  in  alcohol,  54. 
,,     in  glacial  acetic  acid, 
55-57,  329,  347,  349. 
„          , ,     in  water,  53,  54. 
Solubility  of  oils  in  various  solvents, 

55,  341. 
,,     of  wax  in  various  sol  vents,  359. 


Solvents,  extraction  of  oils  by  means 

of,  114,  231-244,  303. 
, ,         for  oils,  &c.  — see  Solubility. 
,,         oils   used  as,  for  odorous 

matters,  302. 

,,  treatment  of  wool  with,  337. 
Souche're,  adulteration  of  olive  oil,  345. 
Soxhlet's  tube,  119,  238. 

,,  modifications  of,  239. 

Specific  gravity  of  alkaline  leys,  415- 

419. 

,,         caustic  soda,  effect  of 
temperature  on,  416. 
,,         lubricating  oils,  325. 
,,         oils,  &c.,  76-94,  341. 
,,         ,,  effect  of  light  on,  130. 
,,         ,,         ,,      temperature 
on,  79,  92-94. 

Specific  temperature  reaction,  149. 
Spectroscope,  absorption,  50. 
Spermaceti,  4,  14,  21,  292,  302,  353, 

359-361. 

,,  added  to  soaps,  448. 

,,  adulterations  of,  360. 

,,  candles  —  see  Candles 

(sperm). 

,,  chiefly  obtained  from  oils 

of  toothed  whales,  293, 
300,  301. 
class,  282,  301. 
,,  foots,  261,  360. 

,,  free   cetylic   alcohol    in, 

116,  171,  361. 

,,  iodine  absorption  of,  182. 

„  refining,  261,  360. 

,,  saponification  equivalent 

of,  161. 

,,  various  physical  proper- 

ties of,  68-70,  88,  91-93,  360. 
Spills,  manufacture  of,  407. 
Spirit    oil    (Yorkshire    grease    dis- 
tillation), 277,  278. 
Spirit  soap  (transparent) — see  Soap- 
making  ;  Soap  (special  kinds). 
Spontaneous  combustion,  132. 

, ,     oxidation,  42,  1 1 3,  1 29  1 37,  323. 
,,        ,,  more  rapid  under  influence 

of  light,  130-132. 
Square  soap  kettles,  433. 
Squirting  soap,  448. 
Stamping  machines,  444,  445. 
Standard  candles  (sperm),  402. 

,,     oils,  preparation  of ,  213,  340. 
,,     water  as,  specific  temperature 

reaction,  149. 

Standards   of   comparison,    oils  and 
mixtures,  &c. ,  340,  346. 
,,        efflux  viscosity,  101. 
„       specific  gravity,  78,  89. 


INDEX. 


565 


Stannic  chloride,  colour  test,  151. 
Starch  as  adulterant  of  beeswax,  359. 
,,  „    fats,  123,  307,  355. 

Starch  in  soft  soap,  459. 
Steam,  distillation  with — see  Distilla- 
tion. 

,,      dry,  428-433,  459. 
,,      kettles  heated   by,  428,  432, 

433,  441,  452,  459. 
,,      twirl  (Morfit's) — see  Morfit. 
,,      wet,  428-433,  459. 
Stearic  aldehyde,  1 4. 
Stearin  (stearic  triglyceride),  4,  11, 

110,  285. 
Stearine,  beef,  307,  309. 

. ,         candle — ste  Candle  stearine. 

,,         candles — see  Candles. 

,,         cokernut,  91,  92,  231,  283, 

305,  3G3. 

,,  ,,         use  for  nigh tlights, 

candles,  &c.,~363, 
364,  407. 

cotton  seed,  91,  184,  230, 
295,  304,  305, 
307,  354. 

,,  ,,    socalled,  from  distilla- 

tion of  foots,  262,  305. 
,,         French,  365. 
,,         lard    (solar    stearine),    93, 

231,  307. 
olive,  230. 
,,         tallow  (pressed  tallow),  231, 

361,  407. 

,,         yield  from  ox  fat.  311,  312. 
Stearines  (commercial  products),  88, 

91-93,  230,  285. 
distilled,  110,  262,  277,  305, 

324. 

,,  ,,         adulteration  of 

tallow  with,  355. 

,,  ,,         from   cotton   seed 

foots,  262,  305. 

,,  ,,         from       Yorkshire 

grease,  277,  355. 

,,  ,,         useinsoapmaking, 

450. 

, ,  expressed  from  natural  oils, 
&c.,  11 0,229, 257, 
305,  309,  407. 

,,  ,,         used  as  lard  adul- 

terants, 307. 

,,  ,,    .        ,,        as     tallow 

adulterants,  354. 

,,         from  animal  oils  and  fats, 

230,231,  307,  311. 

Stearolactone,  30, 39, 143,262,273,384. 
, ,  correction  for  presence 

of,  170,  273. 
Stearyl  cyanide,  21. 


Steatite  added  to  soft  soap,  459. 

,,       (antifriction),  324. 
Stein,  Berge",  and  de  lloubaix,  sul- 
phurous acid  process,  380. 
Stereochemical  isomerism,  29. 
Stills  —  see  Distillation. 
Stoddart,  nitric  acid  test,  140. 
Storax,  16,  19. 
Stripping  (soap),  446. 
Strohmer,   density  of  glycerol  solu- 
tion, 517. 

,,          refractive  index,  51. 
Stiircke,  Carnauba  wax  derivatives, 

18,  37. 

Substitution  derivatives,  bromo,  26- 
28,  30,  31,  34,  38, 
41,  42,  45,  176. 
,,  ,,  chloriodo,  177. 

,,  chloro,  30-32,267,364 
„  ,,  iodo,  26,  27,  30,  31, 

38,    177  —  see  also 
Iodine  number. 
Sudcake,  272. 
Suds,    grease    recovered   from  —  see 

Grease. 

Sugar    in    toilet    soaps  —  see    Soap, 

special  kinds  (transparent). 

,,       test  for  sesame  oil,  &c.,  153, 

346   352. 

Suet,  55,  70,' 91/161,  164,  181,  298. 
Suint,  337. 

Sulphur,  adulterant  of  beeswax,  359. 
,,    candles,  407. 

, ,    chloride  reaction,  154-156,341 . 
„    dioxide  (liquefied)  as  solvent, 

236. 
,,         ,,          use  in  candle  stearine 

making,  369,  370. 
,,    trioxide,  use  of,  in  bleaching 

oils,  264. 

Sulphuric  acid,  action  on  glycerol,  144. 
,,  ,,    isoleic  acid,  38. 

,,  ,,    oleic  acid,  27,  29. 

,,  ,,    olein  and   ricin- 

olein — see  Oils 
(Turkey  red). 

,,     colour  reactions  with  oils, 

151-153,  294,  341,352,354. 

,,     decomposing  rock  by,  366. 

,,     heat  evolved  by — see  Oils 

(heat  evolution). 
,,     preparation  of,  of  constant 

strength,  148. 

,,     presence  of,  in  oils, &c.,  123. 
,,     reaction   with    cholesterol 

and  allied  bodies,  17. 
,,     refining  with,  123, 255,  259. 
,,     removal  of  lime  salts  from 
bone  fat  by,  256. 


566 


INDEX. 


Sulphuric  acid,  saponificatioii  by,  143, 

145,  380-382. 
,,     test  for    hydrocarbons  in 

beeswax,  359. 
,,     use    of,    in    finishing   hot 

press  cake,  368. 
,,       ,,  in  rendering  tallow,  249. 
,,       ,,  in     Yorkshire     grease 

process,  271. 
Sulphurised  constituents  of  oils,  123, 

154. 
Sulphurous  acid  as  bleaching  agent, 

264. 

,,  ,,  saponifying  agent,3SO. 

Sumbul  root,  25. 
Summer  oils — see  Oils,  summer. 

„        railway  grease,  327. 
Superheated  steam — see  Distillation 

(with  superheated  steam). 
Suspended  matters,  action  of.  in  re- 
moving mucilage,  255. 
,,      in  solid  fats,  &c.,  123,  341. 
,,      removal  of,  from  oils,   &c., 

228,  254-256. 

Sustainer  for  night  lights,  406. 
Sweet  water  (crude  glycerol  solution) 

— see  Glycerine  manufacture. 
Sycocerylic  alcohol,  16. 
.Synthesis  of  glycerides,  11. 


TABLES  of  errors,  hydrometer,  82,  83. 

,,       hydrostatic  balance,  83,  84. 

Tablets  (soap),  cutting  and  stamping, 

444. 

Tallow  (ox   tallow,   mutton   tallow ; 

ox,   sheep,    &c. ,   fat ;    beef 

fat),  3,  21,  55,  56,  29 3,  299, 

303,  311,  322,  354. 

, ,       adulteration  of,  1 23,  258,  354- 

356,  370. 

bleaching  of,  264-266. 
candles— see  Candles  (tallow), 
different  varieties  of,  354. 
engine,  324. 
flashing  point,  128. 
free  fatty  acids  present  in, 

355,  356. 

iodine  number,  181-184,  356. 
,,  useful  as  test  of 

quality,  356. 
melting  point,  68,  69,  355. 

,,  of    fatty   acids 

from,    69-71, 
74-76. 

neutralisation      number      of 
fatty  acids  from,  164. 


Tallow  oil — see  Oil  (tallow). 

,,       rancid,     cleansing    of  —  see 

Rancid. 

,,       Reichert  number,  175. 
,,       relative  viscosity,  102-105. 
,,       rendering,  246-251. 
,,       saponification  equivalent  and 
total    acid    number,    159, 
161,  355. 

,,       specific  gravity,  88-93,  355. 
,,       stearine  —  see    Stearine 

(tallow). 
,,       unsaponifiable     matters 

present  in,  257. 

,,       use   of,    in  lubricating  mix- 
tures, &c. ,  322-328,  356. 
,,         ,,     in  soapmaking,  356,  408 

— see  Soapmaking. 
,,       valuation    of,    by    Dalican's 

method,  74,  355. 

,,  „         de    Schepper    and 

Geitel's  tables,  76. 

Tallows,  vegetable — see  Butters,  vege- 
table. 

Tannery  grease,  299. 
Tannin,  use  of,  in  refining,  256,  263. 
Tapers,  389. 

Tar  as  lubricant — see  Lubricants. 
Tariri,  36. 
Taste  of  oils,  &c.,  49,  341. 

,,  improved  by  presence  of 

free  acid,  116. 
Teal,  oil  bleaching,  264. 
Temperature  of  complete  fusion,  61. 
,,       of  incipient  fusion,  62. 
,,       of  turbidity  (Valenta's  test), 

55-57. 

,,       reaction,  specific,  149. 
,,       variation  of  specific  gravity 

with,  92-94,  416. 
,,         ,,     viscosity  with,  102-106. 
Tempering  metals  in  oil  baths,  302. 
Testing  machines,  viscosity,  94. 
Tetrabromides,  31,  34,  36,  176. 
Tetracetyl  derivative,  35. 
Tetrachloride  of  carbon — see  Carbon. 
Tetraiodides,  31. 

Textile  fabrics,  oil  used  in  prepara- 
tion of,  270,  272,  279,  302. 
Texture,  physical,  of  oils,  &c.,  47,  341. 
Thenard  process  (oil  refining),  259. 
Thermal  araeometer,  Langlet's,82,347. 
Thermeleometer,  Jean's,  151. 
Thermohydrometer,  Fletcher's,  80. 
Thermometric  scales,  57. 
Thiocyanic  ethers,  15,  123. 
Thomson  and  Ballantyne,  blown  oils, 

320. 
,,  ,,     iodine  numbers,  180. 


INDEX. 


567 


Thomson  and  Ballantyne,  iodine  num- 
bers of  linseed  oil, 
180,  351. 

,,  ,,     specific  temperature 

reaction,  149,349. 
,,  ,,     unsaponifiable  mat- 

ters, 259. 

,,  .,     Valenta's  test,  57. 

Thousandfold  scale  of  specific  gravity, 

83,  84. 

Thum,  fractional  saturation,  13. 
,,      free  acids  formed  by  hydro- 
lysis, 12. 
Thymol, 

Tilghmann,    hydrolysis   under   pres- 
sure, 385. 

,,  soapmaking  under  pres- 

sure, 463. 

Time  of  efflux — see  Viscosity. 
Titration,  23,  116,  161,  168,  173,  323, 
328,  352,  359,  420— see 
also  Soap  analysis. 
,,         acetyl  number,  198. 
,,         of  alkaline  leys  preferable 
to  density  valuation,  420. 
,,         test,  fatty  acid — see  Soap 
analysis  (determination 
of  free  alkali). 

Toluene  (solvent  for  wax  in  soap),  496. 
Tomlinson,  cohesion  figures,  345. 
Torches,  312,  362. 

Total  acid  number  (saponification 
number,  Kcettstorfer  number),  33, 
157,  168,  194,  341. 

Transparent  soap — see  Soapmaking, 
Soap  (special  kinds),  Colloidal 
state  of  soap. 

Traube,  friction  in  tubes,  109. 
Triacetin,  8,  186. 
Triglycerides,  9. 

,,  synthesis  of,  11. 

Triglycerol,  8. 

Tiinnermann,  specific  gravity  of  alka- 
line leys,  415,  417. 
Turkey  fat,  298. 

,,     red  oils — see  Oils  (Turkey  red). 
Turpentine — see  Oil  (turpentine). 
Turpentine,  crude  (Meinecke's  rosin 

soap),  473. 
Turtle  fat,  299. 

Twaddell,  hydrometer  scale,  84,  86. 
Twitchell,  rosin  in  soap,  503,  504. 

u 

UNIT  mill  (Anglo-American  system), 

217. 

Unsaponifiable  matters  contained  in 
oils,  &c.,  116,257,258,341,355. 


Unsaponifiable    matters    in    candle 

stearine  products,  371-374. 
,,     in  Yorkshire  grease,  273-279. 
,,     determination  of ,  119-124. 
,,     proportions  usually  present  in 
oils,  257,  258. 

,,  ,,         in  soaps,  258. 

Unsapoiiified  fat,   amount  less  with 
longer  time,  373. 
,,  in   red  oils,  370, 

377-379. 

in  rock,  371-374. 
,,  in  separation 

cakes  and  press 
cakes,  376-379. 
,,  in  soap,  119,  371. 

, ,  interferes       with 

crystallisation,370. 
Unsaturated  compounds,  acids,  24. 
,,  alcohols,  15. 

,,  hvdrocarbons,  3, 

"24,  26. 

, ,  oxidation  of,  44. 

Unguents  in  toilet  soaps,  448. 

, ,       lanolin  preparations  as,  338. 
,,       oils  used  for,  302. 
Ure,  soft  soap  analyses,  510. 
Urine,  damaluric  acid  from,  25. 
Utilisation  of  fat  of  an  ox,  311. 

red  oils— see  Red  oils. 


VALENTA'S  test— see  Acid  (acetic). 
Valerin  (valeric  triglyceride),  20,  301. 
Vapour  bath,  AmbuhFs,  80. 
Varnish  making,  302. 
Variation  of  constituents  of  oils  with 
soil,  climate,  &c.,  111. 
,,  density    with    tempera- 

ture— see  Expansion. 
Vaseline,  91. 

,,         in  soaps,  448. 
Vegetable  alkali,  410. 

,,          fats,  butters,  and  tallows 
— see  Butters  (vegetable). 
,,         lard— see  Lard. 
Versmann,    glycerine    manufacture, 

515. 

Villavecchia    and    Fabris,    test    for 
sesame  oil,  346. 
,,  ,,     viscosity,  106. 

Vincent,  boiling  oils,  317. 
Viscidity  of  oils  increased  by  blowing, 

164— see  Oils  (blown). 
Viscosimetry,  94-109. 
Viscosity  (body),  47,  94,  101. 
,,     degree,  102. 


568 


INDEX. 


Viscosity,  determination  in  absolute 

measure,  107. 
„     effect  of  lighten,  131. 
„     efflux,  48,94-106,  324-326,341. 
,,     of  oils  increased  by  addition 
of  caoutchouc,  323. 
„  „      by  blowing,  320. 

,,  ,,      by     metallic     soaps, 

121,  324. 

,,         standards  of,  101. 
Voelcker,   amount  of  oil  in  linseed 

cake,  213. 

Volatile  acid  number,  176,  195,  341. 
„       acids,  22,  113. 
,,  ,,      determination    of — see 

Reichert  test. 

Volatility  of  lubricating  oils,  325. 
Vulcanising,  154,  318. 


W 

WAGGON  grease — see  Lubricants. 
Wagner,  refining  with,  zinc  chloride, 

260. 

,,      rule  concerning  oxidation,  44. 
Wakefield  fat — see  Yorkshire  grease. 
Walton,  linoleum  manufacture,  318. 
Wanklyn,  aldepalmitic  acid,  24. 

,,          and  Fox,  glycerine  valua- 
tion, 519. 

Warren,  sulphur  chloride  and  oils,  155. 
Washballs  (soap),  448. 
Waste  cleansing — see  Engine  waste. 
Water,   action  of,  on  silver  bromo- 

stearate,  25,  30. 
,,        agitation  with,  as  purifying 

agent,  261. 

,,        as  standard  for  efflux  velo- 
city, 101. 

,,  ,,  for  specific  tem- 

perature reaction,  149,  150. 
,,        contained  in  beeswax,  359. 

oils,  122-124,341. 

,,        hot,  extraction  of  vegetable 

oils,  &c. ,  by  means  of, 

200-202. 

,,  ,,     rendering  animal  fats, 

&c.,  with,  247. 

,,        solubility  in — see  Solubility, 

Water  bath  for  melting  points,  60-64. 

,,         ,,         specific  gravity,  80. 

,,         ,,         viscosimetry,  95-101. 

Watt,  bichromate  bleaching  process, 

265. 

,,     chloride  of  soda  bleaching  pro- 
cess for  soaps,  267. 
Watts— see  Richardson  and  Watts. 
Wax  candles — see  Candles. 


Waxes,  animal  and  vegetable — 
Abyssinian,     African,    Andaquia, 

Antilles,  302. 
Beeswax,  4,  14,  21,  357-359. 

,,     addition  of  fatty  matter  or 

oil  of  turpentine  facilitates 

air  bleaching,  268, 269, 358. 

,,     adulterations  of,  359. 

„     air  bleaching,  264,  268,  357, 

358. 
,,  ,,  produces  little  change 

in  density,  358. 
,,     bibliography  of,  359. 
,,     bleached  by  chlorine  apt  to 
contain  chloro  substitution 
products,  267,  364,  390. 
,,     bleaching  by  chemical  pro- 
cesses, 264-267,  357. 
,,         ,,     increases     total     acid 
number,  and  renders 
more    crystalline, 
266,  269,  364 

,,     bromine  absorption,  178. 
,,     class,  282,  301,  302.. 
,,     ester  number,  358. 
,,     free  acid  number,  358. 
,,     fusing  point,  68,  69,  358. 
,,     iodine  number,  269,  358. 
,,     iodine    number    diminished 
by  chemical  bleaching,  269. 
,,     preparation  of  201,  357. 
,,     saponification        equivalent 
and    total    acid    number, 
160,  269. 

,,     solubility  in  solvents,  357. 
,,     specific  gravity,  88,  91-93, 

358. 

,,     virgin,  357. 
Carnauba  wax,  14,  21,  301. 

,,        an  oxyacetic  acid  from, 

37. 

bromine  absorption,  178. 
class,  282,  301. 
glycol  from,  5,  18. 
saponification     equiva- 
lent, 160. 

specific  gravity,  91. 
used  as  beeswax  adul- 
terant, 359. 

Chinese  wax  (Peh-la),  14, 21,91, 302. 
,,  extraction     by     hot 

water  process,  201. 
Cordillera  wax,  301. 
Cowtree  wax,  301.. 
Ficus  wax,  (fig  wax,  Getah  wax), 

14,  301. 

Indian  wax  (Arjun  wax),  302. 
Japanese  wax,  5,  21,  295. 

,,        bromine  absorption,  178. 


INDEX. 


569 


Waxes,  animal  and  vegetable — 
Japanese  wax  contains  practically 

no  olein,  295. 
,,        fusing  point,  68-71. 
,,        iodine  number,  181-184. 
, ,        purification  and  bleach- 
ing, 268. 

,,  saponiti  cation  equiva- 
lent and  total  acid 
number,  160. 

,,        solubility  in  alcohol, 55. 
,,        specific  gravity,  88,  91- 

93. 
,,        unsaponifiable     matter 

contained  in,  257. 
„        yield  of,  242. 
Myrtle  wax,  71,  91,  178,  295. 
Niin  wax  (niin  fat),  302. 
Ocuba  wax,  243,  295. 
Otaba  wax,  295. 
Palm  wax,  301. 
Paraffin  wax,  2,  5,  21,  91-93. 

,,      adulterant  of  bees  wax  and 

spermaceti,  359, 361. 
,,      as    candle    material — see 

Candles. 

„      manufacture  of,  230,  364. 
Pe-la    (Peh-la,    Pe-lah)   wax  —  see 

supra,  Chinese  wax. 
Petha  wax,  301. 

Spermaceti  wax— see  Spermaceti. 
Ucuba  wax,  295. 

Waxes,  free  alcohols  in,  114,  116. 
,,       general  nature  of,  1. 
, ,       glyceridic  and  non-glyceridic, 

3-5,  282,  301,  302. 
,,       liquid,  6. 

,,       mineral  (earthwax) — see  Ozo- 
kerite. 

,,       mostly  indigestible,  303. 
,,       used  as  spermaceti  adulter- 
ants, 361. 
,,       vegetable,  hot  water  process 

of  preparation,  201. 
Waxy  matters,  separation  from  oils, 

119. 
Wedge  presses,  1 99,  203. 

Chinese,  200. 
Wenzell,  expansion,  93. 
Werner,  oxyoleates,  332. 
Westphal,  hydrostatic  balance,  79, 80. 
Wet  steam — see  Steam. 
Whale    blubber,    extraction    of    oil 

from,  247. 

Whales,    toothed,   yield   most   sper- 
maceti, 293,  300,  301. 
Whitelaw,  salting  out  soap,  486. 
Whitelead  in  paint,  135. 
Whiting,  adulterant  of  tallow,  355. 


Wicks,  312,  362,  363,  394. 

,,       charring  of,  116,  260,  313. 
,,       Palmer's  metallic,  394. 
,,       pickling,  394. 
Wilde,  de,  and  Eeichler,  conversion 

of  oleic  into  stearic  acid,  387. 
Wilson,  acetyl  number,  188,  335. 
,,        analysis  of  Turkey  red  oils, 

333-335. 

,,        soap  analysis,  495,  499. 
,,        viscosity,  102. 
,,        water  in  soap,  495. 
Wilson    and    Payne,    hydrolysis   by 

superheated  water,  385. 
Wilson's   process    (preparing   candle 
material),  262, 380, 334. 
„  ,,    (tallow  rendering),  250. 

Wimmell,  melting  points,  68. 
Winter  oils — see  Oils  (winter). 

,,       railway  grease,  327. 
Wire  (soap  cutting),  437. 
Wollny,  Keichert  number,  53,  175. 
Wool  cleansing,  wool  scouring,    271, 

337,  338. 

,,  ,,  injurious  effect  of 

alkaline  and 
silicated  soaps 
—  see  Soap, 
alkaline  ;  Soap 
(special  kinds), 
silicated. 

Wool  fat,  analysis  of,  276. 
Woolgrease,  3,  70,  161,  182,  184,  299, 
302,  337,  461 -.see  York- 
shire grease;  Lanolin. 
,,         effect  on  soap,  258. 
,,         tallow    adulterated    with, 

258,  354,  369. 

Wool  oil  (from  Yorkshire  grease  dis- 
tillation), 279. 

Wright,  Alder  (author),  analyses  of 
manufacturers'  and  toilet 
soaps,  508-512. 

,,         analysis   of  rock,  steariiie 
cakes,      red     oils,      &c., 
371-375. 
, ,         analysis  of  soap  (free  alkali). 

500. 

,,         autoclave  experiments,  373. 
,,         Cantor  lectures,  487,  512, 

523. 

,,         classification   of  soaps  ac- 
cording to  alkalinity,  512. 
,,         dealkalising   process,   453, 

461,  484. 

,,         glycerine  valuation,  523. 
, ,         hydrolysis  of  soap  solutions, 

487. 
,,         methoxyl  test,  192. 


570 


INDEX. 


Wright,  Alder,  use  of  iodine  number 

in  tallow  valuation,  356,  375. 
Wright  (Alder)  and  Muirhead,  zinc 

chloride  and  oils,  141. 
Wright  (Alder)  and  Thompson,  chem- 
istry of  soap, 
490-492. 

,,  ,,       Cladding's  pro- 

cess, 502. 
,,  ,,       hydrolysis      of 

soap,  487. 

,,  ,,       systematic  soap 

analysis,  494. 


XYLENOL,  16. 


YELLOW  ochre,  beeswax  adulterant, 

359. 
Yield  of  fatty  acids  from  oils,  &c., 

74,  163. 

,,      fatty  matter  from  seeds,  nuts, 
beans,  &c., 241-244, 348, 351. 
,,      glycerol  from  oils,  &c. ,  75, 162. 
,,      solid  stearine,  368. 
Yorkshire  grease,  110,  271-279,  324. 
,,   adulteration  of  tallow  with, 

258,  354. 

,,  amount  of  unsaponifiable 
matters  increases  with 
the  density,  277. 


Yorkshire  grease,  analysis  of,  273. 
,,   distillation  of,  277,  383. 
,,    hydrocarbons    in    distilled, 

262. 
,,   injurious  effect  on  soap,  258. 


ZEISEL'S  test — see  Methyl  number. 
Zinc   and   hydrochloric   acid,  as  de- 

chlorinising  agents,  35.  36. 
,,    chloride,  action  on  oils,  141,  142, 

153. 
,,        ,,          action  on  oleic  acid,  39, 

142,  262,  386. 

,,        ,,         colour  test,  153.  341. 
,,        ,,          refining   by   means   of, 

255,  260. 
,,    dust,    as  dechlorinising   agent, 

27,  31. 

,,    isoleate,  30. 
,,    oxide  (antifriction) ,  328. 
,,        ,,     as  saponifying  agent,  379, 

410,  515. 
,,     salts,  separation   of   rapic   and 

erucic  acids  by,  41. 
,,      used  in  refining,  262,  263. 
,,    sulphate  (boiled  oils),  262. 
,,    soap,  added  to  oils,  &c.,  121. 
,,    white,  in  paint,  135. 
Ziirer,  conversion  of  oleic  into  stearic 
acid,  386. 


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