FUR DYEING AND FUR DRESSING

PRINCIPLES AND PRACTICE

OF

FUR DRESSING AND FUR DYEIM

BY

WILLIAM E. AUSTIN, B.S.

CONSULTING CHEMIST TO THE FUR INDUSTRY

ILLUSTRATED

NEW YORK
D. VAN NOSTRAND COMPANY

EIGHT WARREN STREET
1922

, /?6> '

Copyright, 1922, by
D. VAN NOSTRAND COMPANY

All rights reserved, including that of translation into
foreign languages, including the Scandinavian

PRINTED IN THE UNITED STATES OF AMERICA

PREFACE

THE great increase in the use of furs during the past
few decades has caused the fur dressing and dye-
ing industry to rise from relative insignificance
to considerable importance as a branch of applied chemistry.
The past eight years, moreover, have witnessed the virtual
transference of the leadership in the dressing and dyeing of
furs from Europe to America, and in the quality and variety
of products, the domestic industry is now in every way the
equal of, and in many respects superior to the foreign. The
great bulk of American furs which formerly were sent to
Leipzig, Paris or London to be dressed and dyed, are now
being dressed and dyed in this country.

In spite of these facts, very little is generally known about
the nature and manner of the work constituting the dress-
ing and dyeing of furs. Even among members of other
branches of the fur trade, there is very little accurate in-
formation on the subject. Real knowledge concerning fur
dressing and dyeing is possessed only by those actually en-
gaged in the industry. The interest and efforts of scientists
and technologists have been enlisted to only a small extent
in the technical development of the industry. The reason
for this may be attributed to two related causes: first, the
almost monastic seclusion in which fur dressers and dyers,
particularly the latter, conducted their operations, and even
to-day the heavy cloud of mystery is being dispelled but
very slowly; and second, as a consequence of the first, the
lack of any reliable literature on the subject. Of the few
books which have been written on the industry of fur dress-
ing and fur dyeing (all of them either German or French),
most are hopelessly out of date, or contain no trustworthy
data; or, if they do have real merit, they cannot be obtained.

iii

551264

PREFACE

Numerous articles in the technical journals are of interest,
but they contain very little information of value.

This work is intended for a two-fold purpose: first, that
it may serve as a text-book for those who expect to make
fur dressing and dyeing their vocation. The fundamental
principles upon which the industry is based are discussed in
the light of the most recent chemical and technical develop-
ments, and the most important operations are treated fully
and systematically, and are illustrated with practical
examples.

Secondly, as a practical handbook for the worker in the
fur dressing and dyeing plant. The latest factory processes
and methods are described, and numerous working formulas
given. The formulas are all such as have been successfully
used on a large scale, and give satisfactory results when
applied under the proper conditions.

In addition, it is believed that the book will prove of
interest to chemists and other students of industrial chemis-
try, since it will be an introduction into a field of applied
chemistry, about which very little is known to those out-
side of the industry.

Thanks are due to Dr. L. A. Hausman, of Cornell Univer-
sity, for material used in Chapter II; to Dr. E. Lesser of
the American Dyewood Company, for information and
assistance on the subject of Vegetable Dyes; to the Gaskill
Chemical Corp., American Aniline Products, Inc., the
Cassella Company, and the Franklin Import & Export Co.,
for information about their products in connection with the
chapter on Oxidation Colors ; to F. Blattner, Fletcher Works,
Inc., S. M. Jacoby Co., Proctor & Schwartz, Inc., Reliable
Machine Works, Seneca Machine & Tool Co., Inc., and the
Turner Tanning Machinery Co., for the use of the cuts of
the various machines.

WILLIAM E. AUSTIN.

NEW YORK, May, 1922.

IV

TABLE OF CONTENTS

CHAPTER PAGE

PREFACE

I. FURS AND THEIR CHARACTERISTICS 1

Introductory. Knowledge of furs essential. Definitions.
Differences in furs of various animals. Effect of climate on
furs. Effect of age and season on furs. Durability and rela-
tive weights of furs. Description of important furs.

II. STRUCTURE OF FUR 21

The skin. The hair. Under-hair and top-hair. Chemical
composition of furs. Action of chemicals on the skin. Action
of chemicals on the hair.

III. FUR DRESSING: INTRODUCTORY AND HISTORICAL . 29

Objects of fur dressing. Origin of fur dressing. Use of fats.
Use of salt and alum. Use of the tannins. Early organiza-
tions of the fur workers. Modern organizations of the fur
dressing industry.

IV. FUR DRESSING: PRELIMINARY OPERATIONS 36

Flat skins and cased skins. Herbivorous and carnivorous
fur animals. Beaming or scraping. Softening the skins.
Cleaning; hydro-extracting. Fleshing.

V. FUR DRESSING: TANNING METHODS 45

Nature of the tanning process. Chief tanning methods.
Comparison of the tanning methods. Effect of dyeing opera-
tions on the dressing.

VI. FUR DRESSING: DRYING AND FINISHING 71

Importance of the drying process. Methods of drying. A
modern type of drying device. Oiling. Staking or stretching.
Beating and combing. Drum-cleaning. Unhairing and
shearing.

VII. WATER IN FUR DRESSING AND DYEING 85

Importance of water in dressing and dyeing. Water suitable
for dressing and dyeing. Soft water and hard water. Effects
of hardness in water.

VIII. FUR DYEING: INTRODUCTORY AND HISTORICAL... 90

Purposes of fur dyeing. Improvement of furs faulty in
color. Production of a uniform shade on furs. Dyeing furs
to obtain novel effects. Imitation of valuable furs on cheaper
skins. Difficulties due to the hair. Difficulties due to the
leather.

V

TABLE OF CONTENTS

CHAPTER PAGE

IX. FUR DYEING: GENERAL METHODS 98

Two methods of dyeing furs. Development of the dyeing
methods. The brush process. The dip process. Blending.
Drying and finishing the dyed furs.

X. FUR DYEING: KILLING THE FURS 106

Nature of the killing process. Old killing formulas.
Modern killing agents. Procedure of killing. Killing with
soda. Killing with lime. Killing with caustic soda.

XI. FUR DYEING: MORDANTS 114

Nature of mordanting. Purposes of mordanting. Theory
of mordants. Procedure of mordanting. Aluminum mor-
dants. Iron mordants. Copper mordants. Chromium mor-
dants. Tin mordants. Alkaline mordants.

XII. FUR DYEING: MINERAL COLORS USED ON FURS . 125

Mineral chemicals as fur dyes. Lead dyes. Potassium
permanganate as a dye. Other mineral dyes.

XIII. FUR DYEING: VEGETABLE DYES 128

Wood dyes. Old dye formulas. The vegetable dye mate-
rials. The tannin substances. Logwood. Fustic. Brazil-
wood. Other vegetable dyes. Characteristics of the wood
dyes. Application of the vegetable dyes. Application by the
brush process. Application by the dip process. Production
of shades other than black.

XIV. FUR DYEING: ANILINE BLACK 144

Dyeing of seal. Nature and history of Aniline Black.
Chemistry of the Aniline Black process. Three stages in the
formation of Aniline Black. Methods of applying Aniline
Black. One-bath Aniline Black. Oxidation Aniline Black.
Diphenyl Black. Aniline Black by Green's process. Aniline
Black by the dip method.

XV. FUR DYEING: OXIDATION COLORS 155

The original patents. The first Oxidation fur dyes. Early
difficulties. Solution of the difficulties. Progress with the
Oxidation dyes. Para-phenylene-diamine : a typical Oxida-
tion color. Range of shades obtainable. Mordants. Pro-
cedure in dyeing. Typical formulas. Combination of
Oxidation colors with other dyes.

XVI. FUR DYEING: COAL TAR DYES 171

Use of coal tar dyes. Basic colors. Acid colors; dyeing at
higher temperatures. Chrome colors. Vat dyes.

XVII. BLEACHING OF FURS 179

Purpose of bleaching. Steps in the bleaching process.
Methods of bleaching. Bleaching materials with reducing
action. Bleaching materials with oxidizing action. Blueing.

BIBLIOGRAPHY 185

vi

FUK DKESSING AND
y FUE DYEING

CHAPTER I
FURS AND THEIR CHARACTERISTICS

FURS have in general two uses: as the goods which
constitute the basis of the furrier's art, and as the
source of material for the hat manufacturer. In the
latter case, only the hair part of the fur is utilized in the
hat trade for the production of felt, the skin being either
made into leather, or used as the raw material for making
high-grade glue and gelatine. It is the furrier, therefore,
who uses the great bulk of furs, and requires them to be
dressed and dyed.

In discussing the dressing and the dyeing of furs, there
are, broadly speaking, two fundamental subjects to be con-
sidered: first, the raw materials employed, which are, of
course, the skins or pelts as they come from the trapper.
(Other substances used in fur dressing and dyeing are acces-
sories, and will be studied in connection with the processes.)
Second, all those operations, physical and chemical, manual
and mechanical, to which the raw skins have to be sub-
jected in order to obtain the finished fur, ready for use by
the furrier!}

Next to the inherent qualities of the fur skin, the future
value of a fur in a manufactured garment depends largely
on the dressing and dyeing it receives. It is in these opera-
tions that the beauty of the fur can be brought out to its
fullest degree, and if possible, enhanced, or the attractive
features can be marred or destroyed, and the fur rendered
quite worthless. Therefore, it is quite essential for the fur

FUR DRESSING AND FUR DYEING

dresser and the fur dyer in addition to the technical knowl-
edge and experience which are the fundamental requisites
of the industry, also to have more than a superficial famil-
iarity with the various kinds of furs. In fact, an accurate
knowledge of the nature and chief characteristics of furs in
general, and of the individual classes, in particular, is al-
most indispensable to obtain the best results. The habits
and habitats of the various fur-bearing animals are factors
which largely determine the constitution of the fur, and
the nature of the skin. There are as many different kinds
of fur hair, with as many different kinds of skin bearing the
hair, as there are classes of furs. The methods of dressing,
and often, if the furs are to be dyed, the manner of dyeing,
are determined by the nature of these component parts of
furs. Various chemicals affect furs in widely different ways.
The divergence with regard to the physical and chemical
properties of the classes of furs is such as to make almost
imperative a detailed knowledge of the typical members of
the many groups of commercial furs.

To be sure, there are many engaged in the dressing and
dyeing of furs, who never made a formal study of this phase
of the industry, but acquired their knowledge empirically,
and are apparently quite successful. It must not be denied,
that practise and experience, as in every field of enterprise,
are essential to obtaining the best results. But the time and
cost of acquiring this precious experience can be consider-
ably reduced by systematically studying the important
characteristics and properties of furs. These will be treated
briefly, but in sufficient detail to form a basis for discussing
the operations of dressing and dyeing.

^Fur-bearing animals are mammals whose skins are used

' in the manufacture of fur garments and other fur wearing

^ apparel. The skin, when it is removed from the animal is

4- called a pelt, or sometimes, in the case of large animals, a

hide. The pelt, after having been dressed and dyed, is

called a fury the skin part being referred to as the leather,

FURS AND THEIR CHARACTERISTICS

and the hair as the pelage. However, this terminology is
not strictly adhered to in practise, and the various terms are
often employed interchangeably.

The various fur-bearing animals differ considerably in -the
characteristics of the furs they yield. With few exceptions,
notably beaver and Alaska red fox, the depth of shade in-
creases as the habitat of the animal species is nearer the
equatorial regions. There seems to be a direct relationship'
between the intensity of color of the pelt, and the distance
from, or proximity to the polar, or the torrid regions. Thus,
white mammals, such as polar bear, ermine, white or Si-
berian hare, are found only in the northern lands. An ex-
ception is the sheep, which, due to its domestic nature, can
be found in almost all parts of the- civilized world. Tropical
animals on transportation to colder climates, have been
know T n to become lighter-haired when adapted to their new
environment. . The skins of animals living in dense woods
or forests, are generally of a deeper color than in animals
living in more open territory. As a general rule, fur-bearing ,
animals have darker hair on the back than on the sides and
belly. The badger, hamster, ratel and panda are exceptions
having the darker hair on the belly and sides, and the lighter
hair on the back. With regard to the intensity of color, the
skunk has the blackest fur, although some domestic cats
are also quite black. Other animals whose fur is nearly
black, are the black bear, and the black fox, which is a
variety of the silver fox, but the color is often of a brownish
shade. The colors which predominate among animals
of the fur-bearing variety, are white, black, brown, and
grey. Less common are yellow shades, and those known as
blue.

The quality of the fur on all mammals improves with cold, , /
and animals living at greater altitudes, with correspond-
ingly lower temperatures, have thicker and finer hair than
those living nearer sea-level. A cold winter generally pro-
duces fur of high quality and fine color- a mild winter may \

3

FUR DRESSING AND FUR DYEING

f cause the hair to be inferior. In all climates, animals found
in dense woods, have fur which is deeper, silkier, thicker,
and glossier than that of animals living in the open. Ani-
mals inhabiting inland lakes and rivers, have finer and softer
hair than those living near the coast or land exposed to sea
winds. In general, the hair of animals of the cold regions
is short, fine, soft, and downy, while the hair of animals of
warmer lands, is longer, stiffer, and harder.

Both the quality and color of the fur vary with the age
of the animal. The young usually have a thicker coat of fur
than adults, but the hair is too soft, and the skin generally
tender to be fit for use. In certain cases, particularly
(_ /the baby lambs, very young skins are especially prized, and
J eagerly sought, but extraordinary care has to be exercised in
; working with them. Fur is at its best when the animal is
between one and two years old. After this age, the fur be-
comes coarse and scraggy. The animal attains its fullest
growth of hair usually in the height of winter, and the fur
is best between then and very early spring. Before mid-
winter the hair is short and thin, and in the spring it be-
gins to shed, and will continue to fall out even in the dressed
fur. The color of the hair also becomes lighter with age,
and the new growth which generally comes in the fall is
darker than the old coat.

f Different members of the same species, will, other factors
such as age and season being equal, vary as to color and
quality. There may even be several different color phases
^of the same species of animal, such as the cross fox and the
silver fox, both of which are of the same genus as the red
fox; black muskrats are of the same class as the brown
variety, etc. The individual pelt likewise presents many
variations in color and nature of the hair. In some parts,
the hair is thicker and softer than others, and the color
varies in intensity and shade throughout the different sec-
tions of the skin.

Furs do not have differences confined to the hair part

FURS AND THEIR CHARACTERISTICS

only; the leather also presents considerable variation
among the different fur-bearing animals, especially in re-
gard to the weight and thickness. The durability of furs,
relatively considered under similar conditions of wear, also
t varies widely. In the following table the relative durability
of "dressed furs, and in certain instances also dyed furs, otter
being taken as standard, is given, as well as the weight in
ounces per square foot of skin of these furs.

Name gj 1 Durability Wt. in oz.

Otter = 100 per sq. ft.

Astrachan : 10 3 L-~

Bear, brown or black 94 7

Beaver, natural 90 4

Beaver, plucked 85 3% ^

Chinchilla 15 1% ^ I

Civet cat 40 2% '

Coney 20 3^

Ermine 25 \% *""

Fox, natural 40 3 2

Fox, dyed black 25 3

Genet 35 2%

Goat 15 4%

Hare 05 2%^ '

Krimmer 60 3

Kolinsky 25 3

- Leopard 75 4

Lynx 25 2%

Marten, Baum natural 65 2%

Marten, Baum blended 45 2%

Marten, Stone natural 45 2%

Marten, Stone dyed 35 2%

Mink, natural 70 S 1 ^ *-

Mink, dyed 35 _ 3%

Mink, Jap 20 x 3

Mole 07 \^> -1%

Muskrat 45 S 1 ^ u

Nutria, plucked 25 3%

Opossum, natural 37 3 ^

Opossum, dyed 20 3 ^

Opossum, Australian 40 3%

Otter, land 100 4V 2 *-

Otter, sea 100 4% ^

Persian lamb . 65 ZV

FUR DRESSING AND FUR DYEING

Name of Fur Durability Wt. in oz.

Otter = 100 per sq. ft.

Pony, Russian 35 3Mi

Rabbit 05 2V^

Raccoon, natural 65 2 1 /4 ^

Raccoon, dyed 50 2% r/

Sable 60 2V 2

Sable, blended 45 2V 2

Seal, fur 80 3V 2 -

Seal, fur dyed 70 3V 8

Skunk, tipped 50 2 7 /s

Squirrel, grey 20-25 1%

Wolf, natural 50 6y 2 v

Wolverine 100 7 ^

In estimating the value of a fur, many factors have to
be considered. There is no one standard by which the
skins are judged, each kind of fur having its own criterion.
However, the general points by which raw furs are graded
are, color, size, origin, quality and quantity of hair, con-
( dition of leather, date or season of trapping, methods of
handling, etc. Beaver, for example, is graded as large,
medium, small and cubs. Red foxes, first, into Alaska,
Labrador, and Nova Scotia, and then these divisions are
classed as large, medium and small. Skunks are graded
according to the amount of white on the skin, the less white,
the more valuable the fur.

The qualities which make a fur desired depend first of
all on the nature of the fur itself. Pretty color, luster,
thickness, softness, length, uniformity and regular fall of
the hair are the chief points to be considered. While
the leather part of the fur is of secondary importance
in the evaluation of a fur, it must possess strength, light-
ness of weight, and when properly dressed, should be supple
and have a certain firmness or ' feel.' The abundance or
scarcity of a fur-bearing animal also determines the value
of the fur. Furs which are always comparatively rare,
such as silver fox, Russian sable, chinchilla, etc., are always
highly prized. ' In this connection, circumstances which

FURS AND THEIR CHARACTERISTICS

tend to decrease the number of available pelts of any par-
ticular animal, such as pestilences, gradual extermination
due to excessive trapping, prevention of trapping, by pro-
tective laws, also affect the value of a fur. A third factor\
which has an influence on the value of furs, is the prevailing \
style or fashion. Many kinds of furs which are both beauti-
ful and rare, such as Russian sable or chinchilla, are prac-
tically unaffected by the whims of fashion. But a fur of
ordinary value may at times become so popular, that the
demand for it will cause its price to be greatly increased.
Similarly, a fur which has enjoyed a considerable vogue,
may pass out of demand for a time and consequently depre-
ciate in value.

A detailed description of the various furs used in com-
merce is not within the scope of this work, because such
an account rightly belongs in a book on zoology. However,
it is desirable that the reader who is interested in the dress-
ing and dyeing of furs should have at least a passingjacjA
quaintance with the chief furs used in commerce, together l
with such of their individual characteristics as are of im-
portance. The figures given are for the average dressed
skin. 1

Astrachan, see Lambs.

Badger. 2x1 ft. This is one of the few animals
whose fur is darker on the belly than on the back. The
American sorts have coarse, thick under-hair of a pale fawn
or stone color, with a growth of longer black and white hairs
3-4 inches long. The Japanese varieties are usually dyed for
imitation skunk. The American kind is also dyed occasion-
ally but is mostly used natural. Badger hair is very exten-
sively used for ' pointing/

Bear, Black. 6x3 ft. Has fine, dark brown under-
hair, with bright, flowing black top-hair 4 inches long. The
fur of cubs is nearly as long, although the skins are much

1 Descriptions after W. S. Parker, Deputy Chairman, Fur Section ot
London Chamber of Commerce, in Enclyclopedia Britannica, llth Ed.

FUR DRESSING AND FUR DYEING

smaller, and the hair is finer, softer, and lighter-pelted. The
best skins are from Canada,

Bear, Brown. 6 x 3 ft. Similar to the Black Bear, but
more limited in number. The color ranges from a light yel-
low to a rich dark brown. The best and most valuable sorts
come from the Hudson Bay territory, inferior skins coming
from Europe and Asia,

Bear, White. 10 x 5 ft. This is the largest of the
bears. The hair is short and close except on the flanks,
while the color ranges from white to yellow. The best skins
come from Greenland, the whitest being the most valuable.

Beaver. 3 x 2 f t. This is the largest of the rodents,
and is very widely used; formerly to a great extent in the
hat trade. The under-hair is close and of a bluish-brown
hue, and nearly an inch deep. The over-hair is coarse,
bright black or reddish-brown in color, and is usually
plucked out, as the under-hair is the attractive part of the
fur. The darkest skins are the most valuable. Formerly
beaver was used to dye in imitation of seal, but more suit-
able furs are now used.

Broadtail, see Lambs.

Caracul, see Lambs.

Cat, Civet. 9 x 44 inches, with short, thick and dark
under-hair, and silky, black top-hair with irregular white
markings. It is similar to the skunk, but is lighter, softer,
less full, and has no disagreeable odor.

Cat, House. 18 x 9 inches. Is mostly black and dark
brown, the best skins coming from Holland. The hair is
weak, coming out with the friction of wear. In the trade,
the black variety is known as genet.

Chinchilla. 12 x 7 inches. This is one of the rarest
and most beautiful furs. It comes from Bolivia and Peru,
where, due to the uncontrolled trapping of the animal,
it is becoming scarce, and this compelled the governments
to enact laws prohibiting the taking of chinchilla for a cer-
tain period. The fur is of a delicate blue-grey, with black

8

FURS AND THEIR CHARACTERISTICS

shadings, the fur being 1-1 J inches deep. Unfortunately,
the skin is quite perishable.

Chinchilla, La Plata. 9 -X 4 inches. Incorrectly called
" bastard chinchilla " in the trade. It is a similar species
to the Bolivian chinchilla, but due to the lower altitude and
warmer climate of its habitat, is smaller, with shorter and
less pretty hair, the color of the under-hair being darker,
and of the top-hair less pure. It is quite as undurable as
true chinchilla.

Chinchillone. 13 x 8 inches. Is also from South
America. The fur is longer, weaker, poorer and yellower
than real chinchilla, but the skins are often dyed in shades
closely resembling the natural chinchilla.

Ermine. 12 x 2J inches. The under-hair is short and
even, with the top-hair slightly longer. The leather is light,
close in texture, and quite durable. In mid-winter the color
is pure white, except the tip of the tail, which is usually
quite black. The best skins are from Siberia.

Fisher. 30 x 12 inches, with tail 12-18 inches long. It
is the largest of the marten family. The under-hair is deep,
and of a dark shade, with a fine dark, glossy and strong top-
hair, 2 or more inches long. The best skins are from Canada.
The fur is something like a dark silky raccoon, while the tail,
which is very highly prized, is almost black.

Fitch. 12 x 3 inches. It is of the marten species, and
its common name is polecat. The under-hair is yellow and
J of an inch deep. The top-hair is black, 1-J-l f inches long,
very fine and open in growth, and not so close as the mar-
tens. The largest and best skins are from Denmark, Hol-
land and Germany. The Russian skins are smaller, silkier,
and are usually dyed as a substitute for sable.

Fox, Blue. 24 x 8 inches. The under-hair is thick and
long, while the top-hair is fine and not so plentiful as in
other foxes. It is found in Alaska, Hudson Bay Territory,
Greenland and Archangel. Although called blue, the color
is really of a slaty or drab shade. The skins from Archangel

9

FUR DRESSING AND FUR DYEING

are more silky and of a smoky bluish color, and being scarce
are most valuable. The white faxes which are dyed a smoky
blue are brilliant and quite unlike the browner shades of the
blue-fox.

Fox, Cross. 20 x 7 inches. The skins generally have a
pale yellow or orange tone, with some silver points, and a
darkish cross marking on #ie shoulders, on account of which
the animal got its name. Some are very similar to the pale
red foxes of Northwest America. The darkest and best
skins are from Labrador and Hudson Bay, those from
lower latitudes being inferior.

Fox, Grey. 27 x 10 inches. Has a close dark drab
under-hair, with coarse regular, yellowish, grizzly-grey top-
hair. The majority of the skins come from Virginia and
southwestern U. S. A. Those from the west are larger and
brighter-toned.

Fox, Kit. 20 x 6 inches. The under-hair is short and
soft, as is also the top-Kair, which is a very pale grey mixed
with some yellowish-white hairs. It is the smallest of the
foxes, and is found in Canada and northern United States.

Fox, Red. 24 x 8 inches, although some kinds are
larger. The under-hair is long and sof% and the top-hair
is plentiful and strong. The colors range from pale yellow
to a dark red, some being very brilliant. It is widely found
in northern America, China, Japan, and Australia. The
Kamchatka foxes are exceptionally fine and rich in quality.
Farther north, near the open sea, the fur is coarse. The
skins have an extensive use, both natural and dyed. They
are dyed black in imitation of the black fox, or these when
pointed with badger or other white hair to imitate the silver
fox.

Fox, Silver. 30 x 10 inches. The under-hair is close
and fine, and the top-hair, which is black to silvery, is 3
inches long. The fur on the neck usually runs almost black,
and in some cases the black extends over half the length
of the skin. When all black, it is a natural black fox, and

10

FURS AND THEIR CHARACTERISTICS

is exceedingly rare and high-priced. The silver fox is very
valuable, the finest wild skins coming from Labrador. The
tail is always tipped white. The majority of the silver fox
pelts that reach the market today are bred on ranches in
Canada and the United States.

Fox, White. 20 x 7 inches. It is usually small and in-
habits the extreme northern sections of Hudson Bay, Labra-
dor, Greenland, and Siberia. The Canadian are silky-haired
and inclined to a creamy color, while the Siberian are whiter
and more woolly. The under-hair is generally of a bluish-
grey tone, but the top-hair in winter is usually full enough
to hide such a variation. Those skins which have under-hair
that is quite white are rare and much more expensive than
the others. In summer specimens of these species have
slightly discolored coats, the shades resembling those of the
blue fox. The skins which are not perfectly white are
bleached, or if they cannot be bleached sufficiently white
they are dyed various shades of smoke color, blue-greys and
also imitation blue fox.

Goat. The size varies greatly. The European, Arabian
and East Indian varieties are used mainly for leather and
wool. Many from Russia are dyed black for rugs. The
hair is brittle, with poor under-hair, and is not durable. The
Chinese export many skins in grey, black and white, made
into rugs of two skins each. Frequently the skins are dyed
black or brown in imitation of bear.

Hamster. 8x3^ inches. A destructive rodent found
largely in Russia and Germany. The fur is very flat and
poor, of a yellowish -brown color, with a little marking of
black. On account of its lightness it is used for linings; oc-
casionally it is dyed.

Hare. 24 x 9 inches. The common hare of Europe is
used mostly for the hatters' trade. The white hares of
Russia, Siberia, and other northern regions are the ones
mainly used for furs. It is whitest in mid-winter, and the
fur on the flanks is longer than that on the back. The hair is

11

FUR DRESSING AND FUR DYEING

brittle and not durable, and the leather is quite as bad. Yet
the skins are used to dye imitations of more than a dozen
different furs. The North American hares are also dyed
black and brown.

Kangaroo. -- The sizes vary greatly, the larger kinds be-
ing generally used for making leather. The sorts used for
fur are, blue kangaroo, bush kangaroo, wallaroo, rock
wallaby, swamp wallaby, and short-tailed wallaby. Many
of the swamp wallabies are dyed imitation skunk, and look
quite attractive. The colors are generally yellowish or
brown, some in the swamp variety being dark brown. The
skins are quite strong. The rock wallabies are soft and
woolly, and often have a bluish tone. They are used for
rugs.

Kolinsky. 12x2^ inches. It is of the marten family.
The under-hair is short and rather weak, but regular, as is
also the top-hair. The color is usually a uniform yellow.
They are generally dyed in imitation of other members of
the marten family. It is very light in weight, and the best
skins are obtained from Siberia. The tails are used for
artists' " sable " brushes.

Lambs. Those of commercial interest are from South
Russia, Persia, and Afghanistan, and include Persian Lamb,
Broadtail, Astrachan, Shiraz, Bokhara, Caracul, and
Krimmers.

The Persians are 18 x 9 inches, and are the finest and
best. When properly dressed and dyed they should have
regular, close, bright curls, varying from small to very large
and if of equal size, regularity, tightness and brightness,
their value is inestimable.

All the above lambs, except krimmer, are naturally a
rusty black or brown, and are in most cases dyed a jet black.
Luster cannot be imparted where naturally lacking.

Broadtails, 10 x 5 inches, are the young of the Persians,
killed before the wool has had time to develop beyond the
flat wavy state. They are naturally of exceedingly light

12

FURS AND THEIR CHARACTERISTICS

weight, and when of an even pattern possessing a lustrous
sheen are costly. The pelt, however, is too delicate to resist
hard wear.

Astrachan, Shiraz, and Bokhara lambs, 22 x 9 inches, -
are of a coarser and looser curl. Caracul lambs are the very
young of the astrachan, and the finest skins are almost as
effective as the broadtails, although not so fine in texture.

Krimmers, 24 x 10 inches are grey lambs obtained from
Crimea. They are of a similar nature to the caraculs, but
looser in curl, and ranging in color from a very light to a
dark grey, the best being pale bluish-greys.

Slink lambs come from South America and China. The
South American are very small, and generally those are
still-born. They have a particularly thin pelt, with very
close wool of minute curls. The Chinese sorts are much
larger.

Leopard. 3x6 feet long. There are several kinds, the
chief being the snow leopard or ounce, Chinese, Bengal, Per-
sian, East Indian, and African. The first variety inhabits
the Himalayas, and has a deep, soft fur, quite long as com-
pared with the Bengal sort. The colors are pale orange and
white with dark markings. The Chinese are of a medium
orange-brown color and full in fur. The East Indian are less
full and not so dark; the Bengal are dark and medium in
color with short, hard hair. The African are small, with
pale lemon-colored ground, and very closely marked with
black spots.

Lynx. 45 x 20 inches. The under-hair is thinner than
in the fox, but the top-hair is fine, silky and flowing, 4 inches
long, of a pale grey, slightly mottled with fine streaks and
dark spots. The fur on the flank is longer, and white, with
very pronounced markings of dark spots, and this part of
the skin is generally worked separately. Skins with a bluish
tone are more valuable than those with a sandy or reddish
hue. The lynx inhabits North America as far south as
California. The best skins come from Hudson Bay, and also

13

FUR DRESSING AND FUR DYEING

Sweden. They are generally dyed black or brown, similar
to dyed fox.

Marmot. 18 x 12 inches. A rodent found largely in
the south of Germany. The fur is yellowish -brown, rather
harsh and brittle, and without under-hair. Also found in
North America, China, and the best skins come from Russia.
It is dyed brown in imitation of mink or sable, the stripes
usually being put on in the completed garment.

Marten, Baum. 16 x 5 inches. Also called Pine
Marten, and is found in the woods and mountains of Russia,
Norway, Germany and Switzerland. It has a thick under-
hair with strong top-hair, and ranges from a pale to a dark
bluish-brown. The best are from Norway, are very durable
and of good appearance, and a good substitute for the
American sable.

Marten, Japanese. 16 x 5 inches. It is of a woolly na-
ture with rather coarse top-hair, and quite yellow in color.
It is dyed, but it is not an attractive fur, lacking a silky,
bright and fresh appearance.

Marten, Stone. Size and quality similar to the baum
marten. The color of the under-hair is stony white, and the.
top-hair is a very dark brown, almost black. Skins of a pale
bluish tone are used natural, while less clear colored ones are
dyed, usually in Russian sable shades. They are found in
Russia, Bosnia, Turkey, Greece, Germany, and France,
the best coming from Bosnia and France.

Mink. 16 x 5 inches. Is of the amphibious class, and
is found throughout North America, as well as in Russia,
China and Japan. The under-hair is short, close and even,
as is also the top-hair, which is very strong. The best skins
are very dark,. and come from Nova Scotia. In the central
states the color is a good brown, but in the northwest and
southwest, the fur is coarse and pale. It is very durable and
an economic substitute for sable. The Russian species is
dark, but poor and flat in quality, and the Chinese and Japa-
nese sorts are so pale that they are always dyed.

14

FURS AND THEIR CHARACTERISTICS

Mole. 3 J x 2^ inches. Is plentiful in the British Isles
and Europe, and is much in demand on account of its vel-
vety fur of a pretty bluish shade. Although the skins are
comparatively cheap, the cost of dressing is high on account
of the considerable amount of labor involved. The pelt is
very light in weight, but does not resist well the friction of
wear.

Monkey, Black. 18 x 10 inches. The species usually
found on the west coast of Africa, is the one of interest to
the fur trade. The hair is very long, very black and bright,
with no under-hair, and the white pelt is very noticeable by
contrast.

Muskrat, Brown, Black, Russian. 12 X 8 inches. A
very prolific rodent of the amphibious class, obtained in
Canada and the United States. It has a fairly thick and
even brownish under-hair, and a rather strong, dark top-
hair of medium density. It is a durable and not too heavy
fur. It is used natural, but recently the plucked, sheared
and dyed skins have found a very extensive use as Hudson
seal, an imitation of real seal. The so-called black variety
of muskrat is found in New Jersey and Delaware, but only
in comparatively small numbers. The Russian is also very
small and limited in numbers. It is of a pretty silvery-blue
shade with even tinder-hair, with very little silky top-hair,
and silvery-white sides, presenting altogether a marked
effect.

Nutria. 20 x 12 inches. Is a rodent about half the size
of the beaver, and when plucked, has only about half the
depth of fur, which is not so close. It is often dyed a seal
color, but its woolly nature renders it less effective than the
dyed muskrat. The skins are obtained from northern South
America.

Opossum, American. 18 x 10 inches. Is a marsupial,
the only one of its class found outside of Australia. The
under-hair is of a very close frizzy nature, and nearly white,
with long bluish-grey top-hair mixed with some black. It

15

FUR DRESSING AND FUR DYEING

is found in central sections of the United States, and is fre-
quently dyed imitation skunk.

Opossum, Australian. 16 x 8 inches. Is of a totally
different nature from the American. Although it has fur-
hair and top-hair, the latter is sparse and fine, so that the
fur coat may be considered one of close even under-hair.
The color varies according to the district of origin, from
blue-grey to yellow with reddish tones.

Those from near Sidney are a light clear blue, while those
from Victoria are a dark iron-grey, and stronger in the fur-
hair. The most pleasing shade of grey comes from Adelaide.
The reddest are the cheapest. The ring-tailed opossum,
7X4 inches, has a very short, close and dark grey under-fur,
some almost black, but the skins are not used extensively.
The Tasmanian opossum, grey and black, 20 x 10 inches,
is of a similar description, but larger, darker, and stronger in
the under-hair.

Otter, River. The size varies considerably, as does also
the length of the fur, according to the origin. It is found
in greatest numbers in the coldest northern regions, and with
the best under-hair, the top-hair being unimportant, as it is
plucked out. Most of the best river otters come from
Canada and the United States, and average 36 x 18 inches.
The skins from Germany and China are smaller and shorter
furred. The colors of the under-hair vary from very dark
brown to almost yellow. Both the fur and the leather are
extremely strong, and many skins are dyed imitation seal
after plucking.

Otter, Sea. 50 x 25 inches. Is one of the most beauti-
ful of furs. The under-hair is of a rich, dense, silky nature,
with short and soft top-hair, which is not plucked. The
colors range from a pale grey-brown to a rich black, and
many skins have a sprinkling of white or silver-wiiite hairs.
The blacker the under-hair, and the more regular the silver
points, the more valuable is the skin.

Pony, Russian. --This is a comparatively cheap, but

16

FURS AND THEIR CHARACTERISTICS

very serviceable fur, and possesses some very desirable
qualities. It has a thin leather, -but is also scantily haired.
Young pelts have a design on them somewhat similar to
broadtail lambs, or moire astrachans, but this design is lost
to a considerable degree by dyeing the furs. The hair,
which is very glossy, is generally dyed black, although the
natural pelts are also worn extensively.

Rabbit. 10 x 16 inches. The fur is thick and fine, but
the pelt is very weak. It is a native of central Europe,
Asia, North and South America, New Zealand and Aus-
tralia. The color ranges from white to black. France, Bel-
gium and Australia are the greatest producers of rabbits
suitable for dyeing black, the so-called French seal, for
which they are mostly used. At the present time the dyeing
of rabbits constitutes a considerable percentage of the total
fur-dyeing operations in this country. The most varied
shades are produced on rabbit, and it probably is the basis
of the greatest number of dyed imitations of better furs. In
addition to the French seal, or sealine, rabbit is dyed in
imitation of beaver, mole, etc.

Raccoon. 20 x 12 inches. Varies considerably in size,
quality and color of the fur, according to the part of North
America in which it is found. The under-hair is 1-H inches
deep, pale brown, with long top-hair of a dark and silvery-
grey mixture of a grizzly type, the best having a bluish tone,
and the cheapest a yellowish or reddish-brown. The best
skins come from the northern part of the United States.
The skins have a wide use natural, but are also dyed dark
blue, or imitation skunk, the latter being a very effective and
attractive substitute, and extensively used. Sometimes the
skins are plucked, and if the under-hair is good, the effect
is similar to a beaver.

Sable, American and Canadian. 17 x 5 inches. The
skins are sold in the trade as martens, but since many of the
skins are of a very dark color, and almost as silky as Russian
sable, they have come to be known as sable. The prevailing

17

FUR DRESSING AND FUR DYEING

color is a medium brown, while many are quite yellow.
These pale skins have been dyed so well that they can
cheaply substitute Russian sable. The finest skins are from
the Eskimo Bay and Hudson Bay districts, the poorest from
Alaska.

Sable, Russian. 15 x 5 inches. Belongs to a species of
marten similar to the European and American, but much
more silky in the texture of the fur. The under-hair is
close, fine and very soft, the top-hair is regular, fine and
flowing, and silky, ranging from 1^ to 2^ inches in depth.
In color they vary from a pale stony or yellowish shade to
a rich, almost black, dark brown, with a bluish tone. The
leather is exceedingly close and fine in texture, very light in
weight, and very durable. The Yakutsk;, Okhotsk, and
Kamchatka sorts are good, the last being the largest and
fullest-furred, but of less color density than the others. The
most valuable, are the darkest from Yakutsk in Siberia, par-
ticularly those having silvery hairs evenly distributed over
the skin, but these furs are very rare.

The Amur skins are paler, but often of a pretty, bluish
tone, with many interspersed silvery hairs. The fur is not
so close or deep, but is very effective nevertheless. The
paler skins from all districts are now tipped, the tips of the
hair being stained dark, the fastest dyes being used, and
only an expert can detect them as differing from the natural
shades.

Seal, Fur. The sizes range from 24 x 15 inches to
15 x 25 inches, the width being the widest part of the skin
after dressing. The most useful skins are the pups 42 inches
long, the quality being very good and uniform. The largest
skins, known as wigs, and ranging up to 8 feet in length,
are uneven and weak in the fur. The supply of the best
sort is chiefly from the northern Pacific, Pribilof Islands,
Alaska, northwest coast of America, Aleutian Islands, and
Japan. Other kinds are taken from the south Pacific re-
gions. The dressing and dyeing of seal takes longer than for

18

FURS AND THEIR CHARACTERISTICS

any other fur, but when finished, it has a fine, rich effect,
and is very durable.

Seal, Hair. This is chiefly used for its oil and leather,
and not for its fur. It has coarse, rigid hair, and no under-
hair.

Skunk, or " Black Marten." 15 x 8 inches. The
under-hair is full, and fairly close, with glossy, flowing top-
hair about 2^ inches long. The majority of the skins have
two stripes of white hair extending the whole length of the
skin. These were formerly cut out, but more recently are
dyed the same color as the rest of the skin. They are widely
found in North and South America. The best are from Ohio
and New York. The skunk is naturally the blackest fur,
is silky and very durable.

Squirrel. 10 x 5 inches. This size refers to the Russian
and Siberian types, which are practically the only kind im-
ported for fur, other species having too poor a fur to be of
great commercial interest. The back of the Russian squirrel
has an even, close fur, varying from a clear bluish -grey to
a reddish -brown, the bellies in the former being of a flat
quality and white, in the latter, yellowish. The backs are
worked up separately from the bellies. The pelts, though
light in weight, are tough and durable. The tails are dark
and very small, and considerably used.

Tiger. The size varies, the largest measuring about 10
feet from the nose to the root of the tail. It is found
throughout India, Turkestan, China, Mongolia, and the
East Indies. Coats of the Bengal variety are short and of a
dark orange-brown with black stripes. Those from other
parts of India are similar-colored, but longer in hair, while
those from the north and China are not only large in size,
but have very long soft hair of a delicate orange-brown, with
very white flanks, and marked generally, with the blackest
of stripes.

Wolf. 50 x 25 inches. Is closely allied to the dog
family, and very widely distributed over the world. The

19

FUR DRESSING AND FUR DYEING

best are the full-furred skins of a very pale bluish-grey with
fine, flowing black top-hair, from the Hudson Bay district.
Those from the United States and Asia are harsher and
browner. The Siberian is smaller than the North American,
and the Russian still smaller. A large number of prairie-
dogs, or dog-wolves, is also used for cheaper furs.

Wolverine. 16 x 18 inches. Is a native of America,
Siberia, Russia, and Scandinavia, and is of the general na-
ture of the bear. The under-hair is full and thick, with
strong, bright top-hair about 2-J inches long. The color is of
two or three different shades of brown on one skin, the
center being dark, and presenting the general appearance
of an oval saddle, bordered with a rather pale shade of
brown, and merging to a darker shade towards the flanks.
This peculiar character stamps it as a distinguished fur.
It is expensive, and quite valuable on account of its excellent
qualities.

Wombat, Kaola or Australian Bear. 20 X 12 inches.
It has a light grey or brown, close, thick under-hair -J inch
deep, and no top-hair, with a rather thick, spongy pelt. It
is cheap, and well suited for rough wear.

20

CHAPTER II
STRUCTURE OF FUR

4 'MJR is made up of two main components, the hair
|H and the skin, and each of these has a very complex
-"- ^structure j;

In the living animal the skin serves as a protective cover-
ing, and also constitutes an organ of secretion and of feel-
ing.;, consequently it is of a highly complicated nature. The
skin of all fur-bearing animals is essentially the same in
s strtrcture,- -although varying considerably as to thickness
and texture. It consists of two principal layers^ which are
entirely different in structure and purpose, and correspond-
ingly different in both physical and chemical respects: the
epidermis, epithelium or cuticle, which is the, outer layer,
and the derinis or corium. which is. the true skin. (Fig. 1A ).

The epidermis is very thin as compared with the-fiociuaa.Qjg A
'.ftfl outer layer consists of a tissue of cells, somewhat analo-
gous to the horny matter of nails and hair. The inner sur-
face, called the ' rete malpighi,' -rests on f>>p tmp sVln ar>H
is a soft, mucous layer of cells. These cells are spherical
when first formed, but as they approach the surface become
flattened, and dry up, forming the horny outer layer of the
epidermis, which is constantly throwing off the dead scales,
and which is constantly being renewed from below.^Jt., is ,_
from this inner layer of the epidermis that the hair, the
sweat-glands, and the fat-glands are developed.

The corium, or true skin, consists essentially of white,
interlacing fibres of the kind known as connective tissue.
These fibres are themselves made up of extremely fine
smaller fibres, or fibrils, cemented together by a substance
of-srsonrewhat different nature from the fibres, the coriin.
Towards the center of the skin, the texture of the interweav-

21

FUR DRESSING AND FUR DYEING

ing fibres is looser, becoming much more compact at the sur-
face just beneath the inner layer of the epidermis. This
part of the corium is so exceedingly close that the fibrils are
scarcely recognizable. It is in this part that the fat-glands
are situated, while the hair-roots and sweat-glands pass
through it into the looser texture of the corium. The sur-
face next to the flesh is also closer in structure than the
middle portions of the skin, and has somewhat of a mem-
branous character due to the fibres running almost parallel
to the surface of the skin. The skin is joined to the body
proper by a network of connective tissue, frequently full
of fat-cells. This layer, together with portions of theJlesh
which may adhere to it, is removed by the process called
' fleshing/ and this side of the skin is known as the flesh
side. The corium also contains a small proportion of yellow
fibres, known as ' elastic fibres/ which differ physically and
chemically from the rest of the skin substance.

During the course of the development of the embryo ani-
mal, a small group of cells forms like a bulb on the inner side
of the epidermis, above a knot of very fine blood-vessels in
the corium. This group of cells grows downward into the
true skin, and the hair-root which is formed within it, sur-
rounds the capillary blood-vessels, drawing nourishment
from them, and thus forming the papilla. (Fig. 1A).
Smaller projections also form on the bulb, and the fat- glands
are gradually developed. The sweat-glands are formed in
a manner similar to the development of hair.

The individual hair fibre is quite, as complicated in struc-
ture as the skin, and is made up of four distinct parts.
(Fig. IB). 1

(^ The medulla, or pith, is the innermost portion of the hair,
and is composed of many shrunken cells, often connected
by a network which may fill the medullary column partially
or wholly.

1 Descriptions and figures taken from " Mammal Fur Under the Mi-
croscope," by Dr. L. A. Hausman, in Natural History, Sept.-Oct., 1920.

22

STRUCTURE OF FUR

Surrounding the medulla is the cortex, which is made up
of spindle-shaped cells fused into a horny, almost homo-
geneous, transparent mass, and forming a large proportion
of the hair shaft.

In the majority of the fur-bearing animals, there is dis-
tributed within and among the cells of the cortexji pigment
in the form of granules or minute particles, arranged in
the different hairs in fairly definite and characteristic pat-
terns. It is to these pigment granules that the color of the
hair is due primarily. In some cases the coloring matter
ofThe shaft is uniformly diffused and not granular.

A. STRUCTURE OF SKIX.

Cuticle
Cortex

Medulla

Epidermis (outer layer)
Epidermis (inner layer)

True skin or Dermis
Oil gland

Muscles which move the

hair

Follicle (inner layer)

Follicle (outerlayer)

Papilla inclosed in Bulb
Root sheath (inner Jayer)
Root sheath (outer layer)

. Blood and nerve supply
No the hair

FIG. 1

Cuticle

Cortex

Medulla.

/Cuticular
\sca

B. STRUCTURE OF HAIR.

The outermost coat of the hair, or cuticle, is composed
of thin7 colorless, transparent scales of varying forms and
sizes, and arranged in series like the shingles of a roof. It
is on these scales that the lustre or gloss of the hair depends.^
"SniceTustre is due to the unbroken reflection of light from
the surface of the hair, the smoother the surface, the glossier,
it will appear. When the scales of the cuticle are irregular
and uneven, the surface of the hair will not be uniform and

23

FUR DRESSING AND FUR DYEING

smooth, and the light reflected from it will be broken and
scattered, and consequently the hair will not possess a high
degree of lustre. As a rule, the stiff, straight hairs have the
most regular and uniform arrangement of the scales of the
cuticle, and hence are the smoothest and glossiest.

Fur hairs are in general either circular or elliptical in
cross-section, those which are circular being straight or only
slightly curved, while those which are elliptical in cross-sec-
tion are curly like the hair of the various kinds of lambs.

Most fur-bearing animals have two different kinds of hair
on their bodies. Nearest to the skin is a coat of short, thick,
soft and fine hair, usually of a woolly nature, and called the
under-hair, under-wool, or fur-hair. Overlying the fur-hair
is a protective layer of hair, longer and coarser than the
under-hair, and usually straight, hard, smooth and glossy.
This is called the top-hair, over-hair, guard-hair or protec-
tive hair. In some furs, the top-hair constitutes one of the
chief elements of their beauty, while in others, the top-
hairs are removed, so as better to display the attractive
features of the under-hair. The roots of the top-hair are
generally deeper in the skin than those of the fur-hair, and
in some instances where the top-hair is removed, as in the
seal, the roots are destroyed by the action of chemicals
applied to the skin side, the roots of the fur-hair being
wholly unaffected by this treatment.

The fur-hair and the top-hair in the same animal have
different medullary and cuticular structures, and these
characteristics may be used to distinguish the two kinds of
hair. Figs. 2A and B illustrate these differences. In each
case, the two large hairs on the left of the illustration are
the guard-hairs, showing respectively the cuticular scales
and the medulla. On the right are the two fur-hairs showing
the scales and the medulla.

Although composed of many different kinds of tissues,
anti varying so greatly in physical structure, both the skin
and the hair belong to the same class of chemical com-

24

STRUCTURE OF FUR

pounds, namely the proteins. These are highly complex
substances, forming the basis of all animal and vegetable
tissues. There are many different kinds of proteins, varying
somewhat in their constitutions, but all show, on analysis
the following approximate composition of chemical
elements :

Carbon 50-55%

Hydrogen 6.5-7.3%

Nitrogen 15-17.6%

Oxygen 19-24%

Sulphur 0.3-5%

The principal kinds of proteins found in the various fur
structures are albumins, keratin, collagen, and mucines.
Albumins, of which the white of egg is the most familiar

A. HAIR OF EUROPEAN BEAVER.
a. TOP-HAIR, b. UNDER-HAIR.

FIG. 2 B

B. HAIR OF SKUNK.
a. TOP-HAIR, b. UNDER-HAIR.

variety, occurs to some extent in the corium as serum in the
blood-vessels, and also as the liquid filling the connective
tissues, known as the lymph. They are soluble in cold
water, but when heated to about 70 C., they coagulate and
are then insoluble. Concentrated mineral acids and strong
alcohol will also effect coagulation.

Keratin is the chief substance of which all horny parts of
the animal body are composed, such as the hair, nails or
hoofs. It is the principal constituent of the hair, the epi-
dermis, and the walls of the cells of the inner layer of the

25

FUR DRESSING AND FUR DYEING

epidermis, or the ' rete malpighi.' Keratin is particularly
rich in sulphur, and is quite insoluble in cold water. Caustic
alkalies attack keratin-containing parts.

The collagens are the principal proteins of the skin, form-
ing largely the substance of the connective tissue fibres, and
consequently the framework of the skin. They are insoluble
in cold water, dilute acids and salt solutions, and are only
very slowly attacked by dilute alkalies. Dilute acids and
alkalies cause collagen to swell; concentrated acids, vegeta-
ble tanning materials, basic chrome or iron salts cause it
to shrink. By boiling with water, dilute acids or dilute
alkalies, collagen is split up into gelatin or glutin.

The mucines of the skin, intercellular material or coriin,
are soluble in dilute acids, in dilute solutions of alkalies and
of alkaline earths such as lime, and in 10% salt solution,
but insoluble in water, and in salt solutions of greater or less
concentration than 10%. On drying the skin, the mucines
cement the connective tissue fibres, causing the skin to be-
come stiff, horny and translucent. The mucines are also
constituents of the cells of the ' rete malpighi.' The solu-
bility of the mucines in dilute solutions of alkalies and of
alkaline earths causes the epidermis to be loosened from the
corium, when the skins are treated with such solutions for
some time.

When raw skins are boiled with water, the greater part
goes into solution, the residue consisting chiefly of the kera-
tins of the hair and epidermis cells. On cooling, the solu-
tion solidifies to a jelly of gelatine. It combines with both
acids and alkalies. A property of the skin which is of im-
portance in the tanning operation of fur-dressing, and a
quality which also characterizes gelatine, is the capacity to
absorb liquids and swell up, without changing chemically.
Raw pelts swell up easily in pure cold water, but much more
easily in solutions of dilute acids or dilute alkalies, only a
little of the skin material being dissolved. In stronger solu-
tions, the skins swell up less, while more of the skin sub-

26

STRUCTURE OF FUR

stance dissolves, and by prolonged action of strong acids
or alkalies, an almost complete solution of the skin is ob-
tained, without, however, any of the material decomposing.
With very strong alkalies or acids, the skin substance is
broken up into simpler compounds, such as various amines
and ammonia. The swelling action of acids or of alkalies in-
creases with the increase in concentration of the acid or
alkali, but only up to a certain point, after which further
increase in the strength of the acid or alkaline solution
causes a reduction in the swelling, and even produces
shrinkage. In the presence of neutral salts, like common
table salt, sodium chloride, the swelling action of acids, is
reduced, but the action of alkalies remains practically
unaffected.

When treated with the various chemicals, fur hair acts in
a manner quite similar to wool. If it be remembered that
certain classes of furs are derived from animals of the
sheep family, such furs as Persian lamb, krimmer, etc., it
becomes apparent why chemicals should affect furs in nearly
the same way as wool. The great majority of furs differ
from those of the sheep family., in .possessing much greater
resistance to the action of chemicals. The range is a
wide one however, and no exact criterion can be adopted.
As a general rule, the reactions are most marked with fur-
hair of a woolly nature, so this may be taken as a standard
of reference.

Acids have relatively little action on the hair, when
applied in dilute solutions. The scales of the cuticle or epi-
thelium are somewhat opened, the fibre becoming slightly
roughened thereby. Even at high temperatures, the hair is
quite resistant to the action of dilute acids. Concentrated
acids destroy the hair with the liberation or formation of
ammonia, hydrogen sulphide, and various amino acids.
When treated with dilute acids, the hair, especially if it is
of a very woolly nature, retains considerable quantities of
acid, this phenomenon being probably due to the fixation

27

FUR DRESSING AND FUR DYEING

of the acid by the basic groups in the hair. Nitric acid
produces a yellow coloration when applied in dilute solution
for a short time.- Sulphurous acid, the acid formed by the
burning of sulphur, has a bleaching action on the hair.

Alkalies attack the hair, even in dilute solutions, and by
longer action complete decomposition sets in, with forma-
tion of ammonia and amino-acids. Arrfmonium carbonate,
soap, and borax are practically harmless in their effect on
the hair. Sodium and potassium carbonates roughen the
hair on . prolonged action, even in dilute solutions. Cal-
cium hydroxide on continued action removes sulphur from
the hair, causing it to become brittle.

Salts of alkalies and alkaline earths do not affect the hair
at all. Salts of the heavy metals on the other hand, areTab-
"sorbe'd in appreciable quantities. From a dilute solution of
alum, aluminum hydroxide is absorbed by the hair, the
potassium sulphate remaining in solution. Similarly with
copper, iron, and chromium salts, the metal oxides are fixed
by the fibre.

28

CHAPTER III
FUR DRESSING

INTRODUCTORY AND HISTORICAL

;~"MJR DRESSING has a twofold purpose. First of
|H all, the putrefactive processes must be permanently
*- stopped, so that the skin may be preserved as such,
or worked up as some fur garment, without danger of de-
composition. Having taken measures to assure the en-
durance or relative permanency of the pelt, the prime con-
sideration is, of course, the appearance of the hair. The
hair must be so treated that all its inherent beauty is
brought out to the fullest extent. It must be made clean
and soft, and all the natural gloss must be preserved, and if
possible, enhanced.) The appearance of the leather is rela-
tively unimportant, since it is not seen after the furs are
made into garments. Thpre are, however, certain qualities
which it is essential for (the leather to possess after being
dressed, and these are, softness, lightness of weight, elasticity
or stretch, and a certain firmness or ' feel.' /In other words
the important considerations in fur dressing are the employ-
ment of means, and the exercise of care to preserve or even
improve those characteristics of the pelt which make it
valuable.)

The dressing of furs has many features in common with
the manufacture of leather, which is a kindred art. But
whereas in fur dressing the prime consideration is the ap-
pearance of the hair, and the leather is of secondary im-
portance, in the production of leather, the hair plays no part
at all, since it is entirely removed from the pelt. The fun-
damental points of resemblance between leather manu-

29

FUR DRESSING AND FUR DYEING

facture and fur dressing are in those processes and operations
which are concerned with the preservation of the leather,
and rendering it in the proper condition for use.

Both leather dressing and fur dressing have an origin
which may be regarded as identical, and which dates back to
the haziest periods of antiquity. In the course of satisfying
his needs, primitive man killed the animals about him, and
thus obtained his food. The killed animal also furnished
a skin, which after undergoing certain manipulations and
other treatments, could serve as a protective covering, orna-
ment, or defensive weapon. Since the skin in its natural
state was hardly fit for use because of its easy tendency to
putrefaction, it is evident that man had to find some means
of preventing this decay in a more or less permanent fashion,
and moreover had to treat the skin so that it would be suit-
able for use, by rendering it soft and flexible. The discovery
of means to accomplish these purposes was probably one of
the first great steps forward on the path of progress and
civilization.

There are evidences of the use of animal skins in the
earliest periods of antiquity, in fact it is a usage which may
be literally regarded as " old as the hills." One of the
earliest written records of the employment of the skins of
animals as garments, is in the Old Testament, where it
states, " Unto Adam and to his wife did the Lord God make
coats of skins, and clothed them.' j> Numerous other biblical
references indicate the use of animal skins for various pur-
poses, sometimes prepared as leather, with the hair removed.
Among the Egyptians tanning seems to have been a com-
mon occupation. The particularly attractive skins, like
those of the leopard or panther, were especially prized,
and were made up as furs for ornamental wear, rugs and
decorations. The less valuable skins were unhaired and
made into leather. Although the tanning or leather-pro-
ducing processes of the Egyptians are quite unknown,
numerous figures engraved in stone afford an indication to

30

FUR DRESSING INTRODUCTORY

some of the manipulatory operations, such as soaking the
skins, fleshing, softening with stones, stretching over a
three-legged wooden " horse," etc. Many articles, made of
leather, have been found in the various Egyptian sar-
cophagi, and all are in a splendid state of preservation,
after forty centuries, thereby indicating a very efficient
method of dressing animal skins. Likewise, the presence
in the museums of various articles, leather and fur, of As-
syrian, Phoenician and Persian origin, tends to show that
these peoples also possessed a considerable degree of profi-
ciency in tanning. Frequent references in the Greek litera-
ture show that leopard and lion skins were worn as war
cloaks, and they undoubtedly were properly made. In the
Iliad is described an operation for the preparation of skins
for use as garments, and the method seems to be a sort of
chamois dressing.

The first method of tanning skins was, in all probability,
that of rubbing into the skins various fatty materials found
close at hand, such as parts of the animal, fat, brains, milk,
excrement, etc., such an operation constituting the basis of
what is now known as the chamois dressing. One of the
reasons for believing that it was the first process to be used
by primitive man, is the fact that certain undeveloped tribes
and races of the present day still dress skins by it. The
American Indians, even to this day prepare skins by rubbing
in, on the flesh side, the brains of the animals which furnished
the skins. The Eskimos dress skins by rubbing in animal
fats or fish-oil, and subsequently softening and stretching
the skins with their teeth in place of, or for want of other
implements. Usually, however, variously shaped stones
or bones of animals are used to obtain the proper degree of
softness and flexibility. It is true, too, that some of the
skins dressed in this primitive fashion can scarcely be ex-
celled by any dressed with more modern processes and tan-
ning methods.

The next step forward in the preparation of animal skins

31

FUR DRESSING AND FUR DYEING

for use was undoubtedly the utilization of substances found
in the earth. Common salt, sodium chloride, was the most
universally used substance of mineral origin, just as it is
today. Our prehistoric ancestors eventually discovered the
preservative action of salt, and applied it to skins. While it
was effective, it was not sufficiently permanent, so another
mineral, also of very common and wide occurrence was used
in combination with the salt, and the result proved quite
satisfactory. This second common mineral was alum. The
use of alum, which is the basis of numerous tanning pro-
cesses to this day, seems to have been quite a popular method
of ancient times. Artemidorus, a Greco-Roman writer,
mentions the use of alum by the Greeks, and the Romans
are known to have prepared a soft, flexible leather called
aluta (alum leather), by using it. In view of the fact that
Egypt had extensive deposits of alum, it is believed that the
alum-salt process was employed also by the Egyptians in
the preparation of leather. However, the evidence on this
point is not conclusive.

One of the most important methods of producing leather,
either as such or on furs, was with the aid of certain vegeta-
ble extracts, known as the tannins, from which the process
of tanning gets its name. The discovery of the value of
these materials for converting the decaying raw skin into
a leather which could be preserved for an almost indefinite
length of time, and which was flexible and soft as desired,
was of far-reaching importance. For it is only in very recent
times that these tannins have been superseded in part by
new tanning substances whose use is simpler and more
time-saving. Yet there are unmistakable indications that
the tannins were employed for tanning at a period which
reaches back to the dawn of history. Although it is scarcely
probable that the people who used these materials could
have known of the existence or the nature of the particular
substances in the vegetable extracts which actually effect
the tanning action, experience taught them to employ these

32

FUR DRESSING INTRODUCTORY

plants which possessed the highest content of active ingredi-
ents, and which, consequently, were most effective in use.
Tychios, of Boetius, a Greek supposed to have lived about
900 B.C. and mentioned in the Iliad, is considered the oldest
known tanner, and was regarded by Pliny, a Roman writer,
as the discoverer of tanning, and of the use of the various
vegetable tanning materials. At any rate, the Greeks used
the leaves of a so-called tanning- tree, which was probably
the sumach. The Egyptians worked with the acacia, while
the Romans used as tanning materials the barks of the pine,
alder and pomegranate trees, also nut-galls, sumach and
acorns. The Romans were quick to employ methods used by
the peoples whom they conquered, and it is in this way that
they learned the use of many of the plants mentioned, for
tanning purposes.

Many other ancient peoples had various processes of tan-
ning, the methods probably differing in each country. Thus
the Chinese, Syrians, and much later, the Moors, were each
know r n for proficiency in a certain class of leather tanning.
It has been said that in general, even up to modern times,
tanning with nut-galls was the characteristic method of the
Orient ; with oak- tan, that of the Occident, while the use of
alum is regarded as the method peculiar to the Saracens.

In prehistoric times and the early centuries of civilization,
skins or pelts were prepared for use by the individual, the
work usually being done by the housewife and daughters,
while the masculine members of the family were engaged in
hunting the animals and obtaining the skins. At a later
period, when people had advanced to the point where they
lived in cities, the preparing or dressing of skins became cen-
tered in the hands of a comparatively small number of
people, and thus the work took on the aspects of a trade.
The workers in fur were at first the same people who made
leather out of the skin, for the two kinds of work were very
closely associated. During the period of the Roman su-
premacy, historical records show that the furriers, who did

33

FUR DRESSING AND FUR DYEING

all the work connected with furs, from purchasing the raw
skins, dressing them, making them into garments, to selling
the latter, were organized into associations together with
the leather workers. After the fall of the Roman empire,
and throughout the centuries known as the Dark Ages, all
traces of the furriers seem to have been lost, but in the be-
ginning of the Renaissance period in the fourteenth and
fifteenth centuries, we again find records of the furriers, who
were now all members of the furriers' guilds, also in associa-
tion with the leather workers. As formerly, all the work
connected with the production of fur apparel from the raw
furs, was done by the master furrier and his apprentices.
The methods and the implements used, were essentially the
same as in Roman times, and in fact, up to a very recent
period there was very little change in either.

With the advent of the great industrial era at the begin-
ning of the nineteenth century, the guild system became
ineffective, but the furriers continued their work as here-
tofore. Up to about the middle of the nineteenth century,
the furrier continued to be the only factor of any importance
in the fur trade. There was no need for speed in his work,
for the demands of the trade were not so urgent. The fact
that the dressing of furs often occupied two to four weeks
was no deterring factor in his business. However, with the
great expansion of the fur trade about this time, it became
impossible for the individual furrier to do everything him-
self, and keep up with the requirements of his customers.
Specialization commenced, and establishments were set up
solely for fur dressing. The traditional time- and labor-
consuming processes were still used, but the efficiency of
work on a large scale enabled the fur dressers successfully
to fill their orders. But the fur trade continued to grow
by leaps and bounds, and very soon the fur dressers were no
longer able to meet the demands of the trade. It was then
that the science of chemistry came to the aid of the fur
dresser, and helped him meet the exigency. By devising

34

FUR DRESSING INTRODUCTORY

dressing processes which were cheap and efficient, and which
only required several hours, or at the most one or two days,
as compared with as many weeks, the chemist brought the
fur dresser out of his dilemma. And with the adoption of
mechanical time- and labor-saving devices, the fur dressing
industry has made wonderful progress.

35

CHAPTER IV
FUR DRESSING

PRELIMINARY OPERATIONS

THE fur dresser receives the skins in one of two
shapes, flat or cased, depending on the manner in
which they were removed from the animal. Flat
skins, as for example, beaver, are obtained by cutting- on the
"under side of the animal from the root of the tail to the
chin, and along the inner side of the legs from the foot to
the first cut. The skins are either fastened to boards or at-
tached to wooden hoops slightly larger than the skins, so
as to stretch them, and are then carefully dried, avoiding
direct sunshine or artificial heat, as it is very easy to over-
heat the skins and thereby ruin them. The great majority
of skins, however, are cased. The pelts are cut on the
under side of the tail, and along the hind legs across the
body, the skin being then removed by pulling it over-4he
head off the body like a glove, trimming carefully about4he_
ears and nose. The skin is thus obtained inside out. and
is drawn over a stretching board or wire stretcher of suitable
shape and dimensions, so as to allow the skin to dry with-
out wrinkling. The pelts, after drying in a dry, airy place,
are removed from the stretchers and. are ready for the mar-
ket. With some furs, as foxes, the skins are turned hair-side
out while still somewhat moist, and then put on the stretcher
again till fully dried. In most cases, however, skins are sold
flesh-side out. Throughout the various dressing opera-
tions cased skins are kept intact, being turned flesh-side out
or hair-side out according as the processes are directed to
the respective sides. The pelts are only cut open if they

PRELIMINARY OPERATIONS

have to be dyed, or after the manufacturer receives them,
when they have to be worked into manufactured garments.

A distinction which is made by fur dressers and dyers, and
also by the fur trade in general, divides furs into those de-
rived from domestic animals, particularly the various kinds
of sheep, including also the goat species, and those obtained
from other animals by trapping. In fact, at one time, and
to a certain extent even to-day, dressers were divided into
two groups based on this distinction, one class dealing only
with furs obtained from the sheep family, and the other
working with other kinds of furs. This differentiation is not
a simple arbitrary one, but has a rational justification. As
mentioned before, the manner and habit of living of the ani-
mal are important factors in determining the nature and
constitution of its skin, both leather and hair. The structure
of the body being dependent primarily upon the nature of
the food absorbed by the animal, it is only natural that
herbivorous or vegetable-eating animals such as sheep and
goats, should possess fur of a different sort from that of the
carnivorous or meat-eating animals, such as the majority
of fur-bearers are. It also seems clear that furs differing in
their character and constitution should require somewhat
different treatments, and accordingly the methods are modi-
fied when furs like lambs or goats are dressed. To a great
extent, however, the fundamental operations are similar for
all furs, regardless of nature or origin, and these will be
discussed briefly.

Inasmuch as the first great purpose of fur dressing is to
render the skins more or less permanently immune from the
processes of decay, it is necessary to prepare the pelts so
as to be most fit to receive the preserving treatment. The
skins as they are delivered to the fur dresser have, in the
majority of cases, been stretched and dried to preserve them
temporarily, while in some instances, especially with the
larger furs like bears and seals, they are salted and kept
moist. The flesh-side of the pelt still has considerable fleshy

37

FUR DRESSING AND FUR DYEING

and fatty tissues adhering to it, and the hair is generally
soiled and occasionally blood-stained. In order to get ffieT'
pelts into such a condition that they can be worked and
manipulated, they first have to be made soft and flexible.
Very greasy skins are scraped raw in
order to remove as much as possible
of the attached fat, the operation^ being
known as beaming or scraping./ The
typical beam, shown in Fig. 3, consists
of a sloping table usually made of some
hard wood, and placed at an angle of
about 45. It is generally flat, al-
though in some instances convex beams
are also used, about a yard long, 8 to 10 inches wide, and
firmly supported at the upper end. The skin is placed on
the beam, flesh-side up, and is scraped with a two-handled
knife (Fig. 4), always in a downward direction.

FIG. 3. BEAM,

Shaving Knife.

FIG. 4. KNIVES USED IN FUR DRESSING.

The first step in softening the skins is to get them thor-
oughly moistened, and this is variously done, depending
on the nature of the skin. Lambs, for example, require the
gentlest means of wetting them, while rabbits can stand

38

PRELIMINARY OPERATIONS

soaking in water for several days. The manner and duration
of moistening must be adjusted to the character of the pelt.
For the putrefactive processes which were stopped by
stretching and drying the skins, cqntinue as soon as the
pelt is again moistened. The progress of decay causes the
evolution of certain gases, the simplest of which is am-
monia, and eventually, if permitted to proceed, brings about
the complete disintegration of the skin tissue. It has been
found that a certain amount of gas formation is necessary to
loosen up the fibres in order to get the best quality of leather
after tanning. This process must be interrupted at the
proper time and not allowed to proceed too far.

Skins which have been preserved fresh by salting, require
only a comparatively short time (about 2 hours) to become
softened by soaking in clean, soft water. Most dried skins
need a longer treatment before they are sufficiently flexible.
The addition of certain substances to the water facilitates
and accelerates the softening. In some instances salt water
is used for soaking the pelts, the preservative action of the
salt tending to prevent any loosening of the hair. A solu-
tion of \% borax is very effective in rendering the skins soft,
and clean as well. Borax has an exceedingly mild alkaline
action, and causes a slight swelling of the skin tissue, which
then absorbs the water more readily. Being also preserva-
tive and antiseptic, borax tends to prevent decomposition of
the skin tissue. Another chemical of a different nature,
but equally effective is formic acid, used in the proportion
of 1.5-2.5 parts per 1000 parts of water. Formic acid also
induces a swelling of the skin, the pelts being soaked in a
short time, and the antiseptic action of the acid obviates
the possibility of the hair becoming loose. The water used
should be fresh and clean, and the soaking must be stopped
as soon as the skins have become sou ana dexibl&. SMB6-
times the skins are allowed to soak overnight in water, while
in other cases, the pelts are just moistened by dipping in
water until thoroughly wet, and then laying them in a pile

39

FUR DRESSING AND FUR DYEING

for several hours, or overnight. Another method which is
practised with certain types of skins is the use of wet saw-
dust or of sawdust moistened with salt water. The fur skins,
are either embedded in the sawdust or drummed- witilujt_
for several hours, or until sufficient moisture has .bejerL ab^__
sorted to render them flexible. By this means there is no
danger of the skins being over-soaked, or of the hair being
loosened. WJtanJheLgkins have been properly wetted, they
are drawn with the flesh-side across the edge of a dull
knife-blade, in order to help loosen the texture of the skin.
They are then put into a tramping machine and worked
until completely softened. In the case of large or heavy
skins, the moistened pelts are worked on the beam with a
dull beaming knife to impart thorough softness and
flexibility.

The pelts are then cleaned with particular reference to
the hair. With some furs this is accomplished simply by
drumming for several hours with dry sawdust^ whereby the
oil and dirt' are removed from the hair, and the hair is then
"freed from the sawdust by caging. Otfier skins are washed^)
being passed through a weak soap solution for a short time,
the dirty spots being brushed. Occasionally an extract of
soap-bark is used in place of the soap, being even more effec-
tive. The cleansed skins are then thoroughly rinsed to re-
move any of the cleaning material, which would affect the
gloss of the hair if allowed to remain on the skins. Then in
order to eliminate as much as possible of the water in the
skins, they are hydro-extracted, a centrifugal machine of
the type shown in Fig. 5 being used. The basis of its action
depends on the utilization of the principle of centrifugal
force. The machine consists essentially of a perforated
metal basket generally made of copper, capable of being
rotated at a high speed. Surrounding the basket is an iron
framework, polished or enamelled on the inside. The wet
skins are placed in the rotating basket, fur side toward the
perforations, and the water which is thrown off from the

40

PRELIMINARY OPERATIONS

skins passes through the little holes, and is caught up on the
walls of the outside frame, from where it is led off through
suitable ducts. The centrifugal device is properly equipped
with balancing and regulating attachments, as well as with
a brake. The power may be applied by the over-drive or
the under-drive as is most desirable in the particular case.

FIG. 5. CENTRIFUGAL MACHINE.
(Fletcher Works, Inc., Philadelphia)

The inner surface of the basket can also be enamelled or
otherwise made resistant to the action of acids or other
chemicals.

When the skin is removed from the animal, as much as
possible of the adhering fat and flesh is scraped off, but in
spite of this, and in spite of subsequent beaming by the
fur dresser, there is always a thin layer of flesh and fatty
material remaining and this must be removed so as to ex-
pose the corium, enabling the efficient action of the chemi-
cals used in the tanning processes. The process of removing
this undesirable layer from the flesh-side is known asjflesh-
ingx It is a rather delicate operation, requiring considerable
experience and dexterity on the part of the worker, for it is
exceedingly easy to cut into the skin and damage the fur.

41

FUR DRESSING AND FUR DYEING

A fleshing knife of the type commonly used is shown in
Fig. 6. It consists of a sharp blade fastened at a slight angle
from the vertical, with the cutting edge away from the
workman, who straddles the bench, and by drawing the
skins back and forth across the edge of the blade, removes
all flesh and fat, leaving the corium free and clean. Large
skins cannot conveniently be fleshed in this fashion. They

FIG. 6. FLESHING KNIFE ON BENCH.

are placed on the beam, and fleshed with a fleshing or skiv-
ing knife similar to the beaming knife, but consisting of a
slightly curved, sharp two-edged blade having handles at
both ends. Frequent attempts have been made to use suit-
able machines to do this work. A type of machine which has
met with considerable success is depicted in Fig. 7. It is
fashioned after the models used for the fleshing of hides for
leather manufacture, and has special adjustments and regu-
lating devices which afford protection for the hair part of
the fur. From time to time other fleshing machines are put
on the market, yet none of them seems to enjoy any great
popularity, for fleshing is still largely a manual operation.
With some classes of pelts, fleshing presents some diffi-

42

PRELIMINARY OPERATIONS

culties, and chemical means have to be resorted to in order
to loosen the flesh sufficiently to enable proper fleshing. In
the case of large furs like bears, leopards, and the like, which
while of no great importance in the fur trade, are occasion-
ally met by the fur dresser, the skins after being soaked,

FIG. 7. FLESHING MACHINE.
(Turner Tanning Machinery Co., Peabody, Mass.)

and washed with soap-water, are partially dried; then the
flesh-side is treated with technical butter or oil, which is
tramped in. A mixture of salt water and bran is then ap-
plied to the skins, thereby causing a swelling action to set

43

FUR DRESSING AND FUR DYEING

in, and the flesh becomes loosened, and is easily removed by
fleshing on the beam. Seals receive a special treatment
which makes them soft, and gives them greater stretch
after they are tanned. A paste made by mixing a very dilute
solution of caustic soda with an inert substance like French
chalk, china clay, etc., is applied to the corium after the
skins have been fleshed, then the pelts are folded up, and
allowed to lie for several hours. They are then entered
into a dilute solution of calcium chloride and left overnight.
After being washed in a paddle or drum, first with fresh
water, and then in water containing lactic or formic acid to
remove the lime, the skins are ready for tanning.

44

CHAPTER V
FUR DRESSING

TANNING METHODS

yl FTER the pelts have gone through the preliminary
/-\ operations of softening, washing and fleshing, they
>* -^- are ready to receive the treatment which will con-
vert the easily decomposing skin into leather x>f more or less
permanency, depending on the method used/

During the past century, considerable study has been
made both by scientific and technical people, of the prob-
lem of leather formation. Numerous theories as to the na-
ture of the process have been evolved, but even to this day,
no satisfactory explanation has been given which would
account for all the facts as they are now known, so the
matter is still a subject of considerable controversy. Proc-
ter, who is one of the leading authorities on leather today
discusses the development of the tanning theories as
follows :

" The cause of the horny nature of dried skin is that the
gelatinous and swollen fibres of which it is composed not
merely stiffen on drying but adhere to a homogeneous mass,
as is evidenced by its translucence. If in some way we can
prevent the adhesion of the fibres while drying we shall
have made a step in the desired direction, and this will be
the more effective the more perfectly we have split the fibre-
bundles into their constituent fine fibrils, and removed the
substance which cements them. The separation of the
fibres can be partially attained by purely mechanical means.

45

FUR DRESSING AND FUR DYEING

. . . Knapp, to whom we owe our first intelligible theories
of the tanning process, showed that by physical means the
separation and drying of the fibres could be so far
effected as to produce without any tanning agent a sub-
stance with all the outward characteristics of leather,
although on soaking it returned completely to the raw
hide state. He soaked the prepared pelt in absolute
alcohol, which penetrated between, and separated the
fibres and at the same time dried them by its strong affinity
for water. More recently, Meunier has obtained a similar
result by the use of a concentrated solution of potassium
carbonate which is even more strongly dehydrating.

" Knapp made a further step by adding to his alcohol a
small quantity of stearic acid which, as the alcohol evapo-
rated, left a thin fatty covering on the fibres which com-
pletely prevented their adhesion, and reduced their tendency
to absorb water ; and he so produced a very soft and white
leather. Somewhat similar are the principles of the many
primitive methods which apply fatty and albuminous mat-
ters, grease, butter, milk, or brains to the wet skin, and by
mechanical kneading and stretching, aided by capillarity,
work these matters in between the fibres as the water evapo-
rates. Such methods are still used, and enter into many
processes in which other tanning agents are also employed.

" Building upon these facts, Prof. Knapp advanced the
theory that the effect of all tanning processes was not to
cause a change in the fibres themselves, chemical or other-
wise, but merely to isolate and coat them with water-re-
sisting materials which prevented their subsequent swelling
and adhesion. True as this theory undoubtedly is in many
cases, it can hardly be accepted as the whole truth, and it
seems incontestable that frequently the fibres themselves
undergo actual chemical changes which render them in-
soluble and nonadhesive.

" Before Knapp's work, the prevalent theory, at least as
regards vegetable tannage, had been a chemical one, started

46

TANNING METHODS

by Sir Humphrey Davy. If a solution of gelatine be mixed
in proper proportion with one of tannin, both unite to form
a voluminous curdy precipitate; and, according to Davy's
ideas, this was amorphous leather. Against this, it was
urged that even the supposed ' tannate of gelatine ' itself
could not be a true chemical compound, since the propor-
tions of its constituents were considerably varied by changes
in the strength of the solutions, or by washing the precipi-
tate with hot water; and further, that in chemical com-
pounds, the form was changed, and no trace of the original
constituents appeared in the compound; while in leather
apart from some change of color and properties, the original
fibrous structure remained unaltered.

" This reasoning appears much less conclusive now than
it did in Knapp's day. Against the last objection guncot-
ton may be quoted as an instance of profound chemical
change with no alteration in outside appearance; and it
is recognized that, especially among complex organic sub-
stances, chemical reactions are rarely complete, but that
stable positions are reached, so-called ' equilibria/ in which
the proportion of changed and unchanged substance is de-
pendent on concentration or other conditions; and that
therefore such a precipitate might well be a mixture of gela-
tine with a true gelatine tannate from which further por-
tions of tannin might be dissociated by water.

" With the clearing up of old difficulties, however, the
conflict between chemical and physical theories has, as
is usually the case, merely passed into a new phase. Years
ago, it was shown by Linder and Picton and others, that
liquids could be obtained which were not really solutions of
ions or molecules, but merely suspensions like that of clay
in water, or butter-fat in milk; but so finely divided as to
appear clear and transparent, and pass through filters like
true solutions. Later, by means of the ultra-microscope
their discrete particles have actually been made visible, each
of them consisting of many molecules of the suspended

47

FUR DRESSING AND FUR DYEING

substance. Nevertheless, these particles have many mo-
lecular properties, possessing plus or minus electrical
charges; behaving like large ions under the influence of an
electrical current ; and mutually precipitating and neutraliz-
ing each other when positive and negative are brought to-
gether. Such solutions are called l colloid/ and those of
gelatine and tannin are of the class, so that it is now often
said that the precipitation of gelatine by tannin, and the
fixation of tannin by gelatinous fibre are merely ' colloidal '
and i physical/ and not ' chemical ' phenomena. Admitting
the facts, the question still arises whether the distinction
between chemical and physical is not here one without a
difference; and whether between the purely ionized dilute
solution of a salt and the coarsely granular clay suspension
there is any point where a definite line of demarcation can
be drawn. The writer inclines to the view that there is
not; and that ionic and colloidal combinations are extreme
cases of the same laws, both physical, and both chemical."
There are several methods which are used in tanning
furs, each having its peculiar characteristics and qualities,
and possessing individual advantages and disadvantages.
In order to be able to judge the merits of the various proc-
esses, it is necessary to have a criterion which can serve
as a basis of reference. Fahrion, a recognized authority
and investigator in this field, gives a definition of leather
which is usually accepted as a standard for comparison. He
says: "Leather is animal skin, which on soaking in water
and subsequent drying does not become hard and tinny, but
remains soft and flexible ; which does not decay in the pres-
ence of cold water ; and which does not yield any gelatine on
boiling with water." While the requirements set forth in
this statement are essential for leather, and a compliance
with them would also be desirable for tanned furs, a some-
what less rigorous standard of conditions to fulfil is satis-
factory for the general needs and purposes of furs. The
chief qualities which tanned furs must possess, with par-

48

TANNING METHODS

ticular reference to the leather side of the pelt, are reten-
tion of softness and flexibility after being moistened by the
furrier for manufacturing purposes, and subsequent drying ;
and freedom from a tendency to decay during this opera-
tion and thereafter. If the furs are to be dyed, the effect
of the dyeing must also "Be considered, and the tanning must
be such as to enable the dyed furs to possess the above
qualities.

/The most important tanning processes employed for furs
are the following:

1. Salt-acid tan, or pickle.

2. Mineral tans.

3. Chamois tan.

4. Formaldehyde and similar tans.

5. Combination tans.
6~ Vegetable tan.

1

. SALT-ACID TAN, OR PICKLE

This is one of the most extensively used methods for tan-
ning furs, and is also very cheap and easily applied. A
typical formula for this tan is the following: A solution of
salt is prepared containing about 10% of common salt,
sodium chloride, and to this is added ^-f ounce of
sulphuric acid for each gallon of tanning liquor. The
proportions may be varied within certain limits, but
the figures here given are those which have proven
successful in practise. The solution should be made
in a wooden or earthenware container, free from any
metal, as it would be attacked by the acid. The liquor
is then applied to the flesh-side of the fleshed skins
by means of a brush, making sure to touch all parts
of the pelt. They are then placed in a pile and allowed to
remain thus until tanned, an operation which occupies a
"""time ranging from a few hours to two or three days de-
pending on the thickness of the skins. When the corium

49

FUR DRESSING AND FUR DYEING

has lost its translucence and has become of a milky-white-
color throughout the entire thickness of the skin, as can
be seen by viewing a cross-section, the skinjriay be con-
sidered tanned. In some instances, where the hair of the
fur can stand immersion without injury, the skins are
entered into the pickling solution and allowed to remain
for 12 to 24 hours, which is generally a sufficient time to
tan them in this manner.

The acid of the pickle causes the skin to swell, the salt
then penetrating between the fibres of the corium, and at
the same time reducing the swelling of the skin. The acid
also neutralizes the alkaline products of decomposition
which may form, while the salt acts as a deterrent to the
progress of the putrefactive processes. When the skin is
dried after tanning, and stretched and finished, a soft white
leather is obtained which is permanent as long as it is kept
dry. It is the salt which causes the fibres of the skin to be
completely differentiated and thus prevents their adhesion.

It is interesting to note that other acids besides sulphuric
can be used for the pickle, organic as well as mineral,
formic acid in \% solution being especially effective and
giving excellent results, but is more expensive than the
mineral acid. A method, which in principle is identical
with the pickle, but carried out in an entirely different
manner, is the lactic acid fermentation process, or " Schrot-
beize " as it is called in German. The procedure is in
general as follows: " The fleshed skins are placed on tables,
flesh-side up, and covered with a layer of bruised barley-
grains, or a mixture of 3 parts of wheat bran and 2 parts of
rye flour. Then the head, tail and legs are turned inward,
and the skins rolled up in little cushions, hair-side out, and
placed in a vat. When this is filled with the skins a solu-
tion of common salt is poured over them, and they are
allowed to remain thus in a moderately cool place for 24
hours. After this time, the skins are carefully unrolled, so
as not to remove any of the adhering solid materials, and

50

TANNING METHODS

turning the skins hair-side inward, they are laid flat to-
gether in paies and placed in an empty vat. After another
24 hours they are again unpacked and replaced in another
vat, care being taken each time to keep all the solid par-
ticles adhering to the flesh-side. This operation is con-
tinued and repeated until the skins are properly tanned,
which takes from 10 to 14 days, depending on the weather
and the temperature. The skins are then removed, rinsed
free of the tanning substances, pressed, dried and finished."
A somewhat modified form of this process is the so-called
Russian tan, which is usually done in the following man-
ner: 5 parts of bruised barley grains are mixed with ten
parts of luke-warm water in a vat, which is then covered
up. A small quantity of brewers' yeast is also added to aid
in the fermentation. As soon as the mixture develops a
slight heat, one part of fresh whey is added, and the fleshed
skins entered into the tanning liquor in which they remain
for about 12 hours. They are then tramped in the mixture
so as to effect greater penetration, and left until the tanning
process is complete. Whey is the milk fluid left after the
casein and most of the fat have been removed from the
milk by coagulation, and consists practically of a solution
of all the milk-sugar or lactose, and the lactic acid of the
milk, together with a small percentage of mineral salts,
and a slight amount of fat. By fermentation, the milk-
sugar is converted into lactic acid, which helps to effect
the tan by swelling the skin.

The effectiveness of the fermentation processes depends
to a considerable degree on the action of certain bacteria
and yeasts. Bacteria are one-celled organisms belonging to
the vegetable kingdom, and some are so small as to be
scarcely visible under a microscope, while some indeed can-
not be seen by any means, their existence being inferred
from their effects. As they vary in size, bacteria also vary
in shape, some being spherical, others in the form of long,
thin rods, while still others are of a spiral shape; another

51

FUR DRESSING AND FUR DYEING

common form is the dumb-bell shaped bacterium. Some
types are provided with what are known as flagella, which
resemble fine hairs attached to the body of the organism,
and which enable it to move about actively in liquids. The
food of bacteria is always in liquid form, as only in this
condition can it be absorbed. However, some kinds of bac-
teria attack solid substances from which they obtain their
nourishment, but this is done in an indirect way, by secret-
ing certain fluids known as enzymes, which dissolve or
digest the material and convert it into a form that can
easily be absorbed by the bacteria. The enzymes are non-
living chemical substances, which possess the peculiar prop-
erty of bringing about the chemical change of an almost in-
definite amount of material upon which they act, without
themselves being in any way changed. Yeasts also act in
a manner similar to the bacteria in causing various chemi-
cal changes, particularly inducing fomentations. In the
simple " Schrot-beize," the starch contained in the bran or
barley grains is first converted to a soluble sugar by means
of enzymes secreted by the bacteria which are always
present. This sugar then undergoes an acid fermentation,
with the formation of lactic and acetic acids, due in this
case to organisms known as the bacterium fur juris A and
B. The action of the Russian tan is similar, but quicker.
In this case, the sugar is already present in soluble form,
and the yeast cells cause its fermentation with the produc-
tion of lactic acid. In both cases, the acids as they form
swell and loosen up the skin fibres slowly, the salt penetrat-
ing between them, and keeping them separated on drying.
Both methods give results which are equally good, but by
the Russian tan the skins acquire a disagreeable odor,
which makes this method of dressing objectionable.

The lactic acid fermentation processes have an advan-
tage over the pickle, in that the slow formation of weak
organic acids with their gradual action produce a softer
leather, with a gentler ' feel,' the presence of the flour and

52

TANNING METHODS

the grains of the tan, aside from their tanning action, con-
tributing to the fullness and softness of the leather. There
is also less likelihood of the leather being subsequently af-
fected by the presence of the acid in it, as lactic and acetic
acids are much less injurious than sulphuric acid to leather.
These disadvantages of the pickle can to a large degree,
be overcome without any great difficulty. On the other
hand, the matter of the length of time of the tanning
process, shows the acid pickle at a great advantage, and
so, especially for furs other than those obtained from sheep
and goats, the pickle is in most cases used as the principle
method of tanning. In Austria, Russia, and to a certain
extent in Germany also, the " Schrot-beize " is still con-
siderably employed, chiefly for dressing sheep and lamb
skins. The dressing of the various kinds of Persian lambs,
caraculs, astrachans, etc., in the native center of the in-
dustry in Buchara and surrounding districts, is also a
" Schrot-beize," barley, rice flour or rye flour, and salt water
being used to prepare the skins, the manipulations being
essentially the same as those described above, although
carried out in cruder and more primitive fashion.

2. MINERAL TANS

The basis of the tanning of furs by means of solutions
of mineral compounds is the fact that the basic salts of
certain metals are capable of producing leather. It has
been found that compounds of aluminum such as alum or
aluminum sulphate, or any other soluble neutral salt of
aluminum, possess tanning powers. Other metals which
are capable of forming salts of the same type are also en-
dowed with the quality of converting skin to leather under
suitable conditions, chromium and iron being the most im-
portant metals in this connection. Chemically these
metals all belong to the same group, and have properties
which are very similar in many respects, the characteris-

53

FUR DRESSING AND FUR DYEING

tic of most importance for tanning purposes being the
quality of forming soluble basic salts by the addition of
alkalies or alkaline carbonates to solutions of their neutral
salts, or in certain instances simply by the action of water
upon these neutral salts. By neutral salts are meant those
in which the metallic content is combined with the nor-
mal proportion of acid ; while basic salts are those in which
the acidic portion is present in less than the normal ratio,
being partially replaced by a hydroxide group. When the
acid part of the salt has been entirely replaced in this way.
the compound is called a hydroxide or hydrate of the metal.
Between the neutral salt and the hydroxide several different
basic salts are possible, some being soluble, while others are
insoluble. If into a solution containing a basic salt of either
aluminum, iron or chromium a skin be entered, a part.nl-
the basic salt will be precipitated on it in insoluble form:.
Inasmuch as neutral salts of these metals when dissolved in
water split up to a small degree, into free acid and soluble
basic salt, a skin immersed in such a solution will also ab-
sorb the basic salt in an insoluble form. Upon these facts
in general, depends the action of the mineral tans used in
tanning furs.

A. Alum Tan

The alum tan is one of the oldest methods of producing
leather, being employed by the Romans about two thou-
sand years ago, and it is believed, by the Egyptians at a
much earlier period. Its extensive use in Europe, however,
dates from the time of the conquest of Spain by the Moors,
who introduced the process.

At the present time, rabbits and moles are tanned by this
process, as are also at times other furs such as muskrats,
squirrels, sables, martens, etc., when a better tan is desired
than that produced by the pickle. Ordinary alum, which is
a double sulphate of aluminum and potassium, and alumi-
num sulphate are the chief compounds used for this tan.

54

TANNING METHODS

In recent years, the aluminum sulphate has to a consider-
able degree replaced the alum for tanning, inasmuch as it
can be cheaply obtained in a sufficiently pure form, and
contains about one and one-half times as much active
aluminum compound as does alum.

While the aluminum salt can be used alone for tanning,
it produces a stiff, imperfect leather, so salt is always
added. The ratio of the salt to the aluminum sulphate or
alum can vary within rather wide limits, the mixtures used
in practise ranging from one part of salt to four parts of
the aluminum compound, up to equal parts of both, or even
in some formulas, a greater proportion of salt than of the
other constituent. Ratios which are most common are four
of alum to three of salt, or two of alum to one of salt.

When aluminum sulphate is dissolved in water, a small
part of it splits up into a soluble basic salt and an equiva-
lent amount of free acid. The reaction may be shown as
follows :

A1 2 (S0 4 ) 8 + 2H 2 = A1 2 (SO,) 2 (OH) 2 + H 2 S0 4

aluminum water basic aluminum sulphuric

sulphate sulphate acid

When a skin is entered into such a solution, the free acid
is absorbed, causing a swelling of the pelt. While this is
taking place, a further quantity of the neutral aluminum
salt splits up into more basic salt and free acid. At the
same time the basic aluminum sulphate is also taken up
l>y the skin, probably attaching itself to some of the acidic
groups contained in the skin substance, in a manner analo-
gous to the combination of the acid with the basic groups
of the skin substance. A point is reached, however, when
the skin is no longer able to take up more of the basic salt,
for the presence of the acid undoubtedly acts as a deterrent.
The skin, if dried after such a treatment contains a small
amount of aluminum, which is insufficient to tan the pelt
properly, and as a result this comes out in an undesirable

55

FUR DRESSING AND FUR DYEING

and quite useless condition. If to the solution of the alumi-
num sulphate salt is added, a different result is obtained.
To a certain extent the salt acts here as in the pickle. The
skin on absorbing the free acid of the solution naturally
swells, but the salt reduces this swelling, and at the same
time, by penetrating between the fibres and dehydrating
them, produces a leather as in the pickle. In addition, the
presence of the salt enables a greater amount of basic
aluminum sulphate to be formed, and thus a greater quan-
tity is taken up by the skin. On drying and stretching
after such a treatment, a soft, flexible and stretchable
leather is obtained.

The number of formulas for tanning furs by this process
is legion, the principle being the same in every instance,
and mixtures of salt and alum or aluminum sulphate form
the basis of the various tans. Following are a few
typical formulas, which have been found to be of practical
value :

A solution is prepared by dissolving 7.5 Ibs. of alum and
3 Ibs. of common salt in 20 gallons of water. When cool,
the clean, fleshed skins are entered, being paddled or
drummed for a short time and then allowed to remain
until tanned. By this method the hair also takes up some
of the alum, and if the skins are to be dyed, unevenness
may result. In order to avoid this, the tanning may be
effected by brushing a stronger solution on the pelt. A
mixture of 4 Ibs. of alum and 3 Ibs. of salt, dissolved in 8 gal-
lons of water, and made into a paste by the addition of 4
Ibs. of flour, is applied to the flesh-side of the skins. These
are then placed in pairs, flesh-side together, and allowed
to remain in a pile until tanned. Sometimes a second ap-
plication is given. The flour may be omitted, but it serves
to cause the tanning mixture to adhere better to the skins.

Still another method is the following: Into the flesh of
the moist, fleshed skins is rubbed a mixture of two parts
of dry powdered alum with one part of salt. After allowing

56

TANNING METHODS

time for it to be absorbed, another application is given, rub-
bing in well, and especially treating the thick parts. The
pelts are then folded up, or rolled together, flesh-side in, and
placed in a vat or tub, which is covered up to prevent dry-
ing. They are left so until tanned, as shown by examina-
tion and test. They are then rinsed, hydro-extracted and
dried, and after stretching and finishing, a soft, white, pli-
able leather is obtained.

B. Chrome Tan

By using chrome alum instead of ordinary alum, to-
gether with salt, skins can be tanned, but the leather formed
is not altogether satisfactory. The basic principle here is
the same as in the alum tan, depending on the formation
of soluble basic chrome sulphates in the solution of a neu-
tral sulphate. The method employed at the present time,
the so-called one-bath process as distinct from the two-bath
process, which cannot be applied for tanning furs, involves
the production of the basic chrome sulphate by the addi-
tion of an alkali or an alkaline carbonate to the solution of
the neutral salt. It was Prof. Knapp who first published
this process as early as 1858 ; but it was not until 1893 that
it was shown to be of practical value, and was then patented
in this country by Martin Dennis. Since that time it has
been in general use with but slight modifications, i

The chrome tan is used only to a limited extent in the
tanning of furs, the method requiring very careful treat-
ment and accurate supervision during the various stages of
the process, and the leather coming out colored a pale-blue-
green tint, which for some purposes is objectionable. In
some plants ponies and rabbits are tanned with chrome;
and when the skins are to be dyed by means of certain coal
tar dyes, they have to receive a chrome tannage. The
leather produced by a chrome tan is very durable, and pos-
sesses great resistance to the action of water.

57

FUR DRESSING AND FUR DYEING

Any salt of chromium, with either mineral or organic
acids, can be used, but chrome alum is the one most com-
monly employed. If a skin is entered directly into a solu-
tion of a chrome salt made basic with an alkali, the precipi-
tation of the insoluble basic salt will take place very rapidly,
and the tanning will be only superficial. The procedure
is therefore first to treat the skins with a chrome solu-
tion which forms only small quantities of the basic salt.
After the skins are impregnated with the solution, this is
made basic, so that the real tan will take place within the
skin tissues among the fibres of the corium. A common
formula is the following: 5 Ibs. of chrome alum are dis-
solved in 10 gallons of water. The skins are entered into
the solution at about 70 F. and paddled for about 2 hours,
or drummed for one hour. Then a solution of three pounds
of washing soda is added slowly to the liquor which is then
stirred up well, and the skins drummed or paddled again
for an hour or two, and then left in the liquor for 12 to 24
hours till completely tanned. The skins are rinsed, and
washed in a \% solution containing f % of the weight of
the skins of borax. The pelts are then well washed in clean
water, hydro-extracted and dried.

C. Iron Tan

Tanning by means of iron salts has thus far been merely
a matter of scientific interest and has not found any practi-
cal use. The principle involved is identical with that of
the preceding mineral processes.

3. CHAMOIS TAN

The chamois dressing, as previously noted, is undoubt-
edly the oldest method of preparing leather from skin, the
various fat-containing substances derived from animals,
fish, birds, etc., being used for the purpose. The chief ob-
ject of the fat was to coat the fibres of the skin, thus pre-
58

TANNING METHODS

venting their adhesion, and at the same time rendering
them resistant to water. In the true chamois tan, the
fat seems to have also a chemical function in contradistinc-
tion to the other which is merely physical or mechanical.
For, if skins tanned by the chamois process be treated with
a weak solution of an alkali, all the fatty materials should
be removed thereby, but this happens only to a small ex-
tent, the pelt retaining its softness and pliability, and the
other characteristic qualities of leather, indicating that the
fat is combined intimately with the skin substance in a
permanent fashion.

In tanning furs, various oils and fats are used, but not
all are capable of producing a chamois tan. Among the
fatty materials are mineral oils, and vegetable and animal
oils and fats. Mineral oils are the distillation products
of petroleum, partially liquid, and partially solid. Being
inert substances, they have no tanning effect, but serve
merely as water-proofing or fattening materials. Except
for their oily nature they have nothing in common with
fats, being quite unaffected by solutions of alkalies or of
acids.

Vegetable and animal fats and oils are, when pure,
neutral substances formed by the combination of fatty acids
with glycerine. They possess the property of saponifica-
tion, that is, of forming a soap when treated with an alkali,
the soap being the alkaline salt of the fatty acid. Under
certain conditions, the fat can be split up into free fatty
acid and glycerine by the action of acids, or even water
alone. Some fats on long standing, split up in this way
spontaneously in the presence of moist air. As a general
rule, those fats which exhibit this property to a marked de-
gree are affected by contact with the air, due to the ab-
sorption of oxygen which reacts chemically with the fats,
forming what are known as oxy-fatty acids, usually less
soluble, and having a higher melting point than the original
fats. Vegetable and animal fatty materials are classified

59

FUR DRESSING AND FUR DYEING

on the basis of this phenomenon of absorbing oxygen from
the air, those possessing this quality to a great degree be-
ing called " drying oils/' others being " partially drying,"
or " non-drying." Olive oil, castor oil, cocoanut oil and
cottonseed oil are examples of non-drying or partially-dry--

FIG. 8. TRAMPING MACHINE OR " KICKER/'
(F. Blattner, Brooklyn, New York.)

ing vegetable oils, linseed oil being the most important
drying-oil in this class. Tallow, lard, butter-fat, neats-foot
oil are non-drying animal fats, the drying oils being seal
oil, whale oil, and cod-liver oil.

For tanning purposes, this property of absorbing oxygen
is important, because only with drying oils can a true
chamois tan be obtained, non-drying oils acting like mineral

60

TANNING METHODS

oils only as water-proofing materials. The details of the
chamois process are not quite clear, there being considerable
difference of opinion on the matter. But all the studies on
the subject tend to prove that there are at least two phases
to the process: first, the mechanical covering of the fibres
with the fat, this property being common to all fats or oils
which may be used; and second, the combination of the
fat with the skin in some chemical way, as a result of the
oxidation of the fat, a characteristic found only in the dry-
ing oils. During the oxidation of the fats, the glycerine in
them is converted to acrolein or acryl-aldehyde, which also
aids the tanning. It was at one time supposed that the tan-
ning action was due to this aldehyde alone, but a chamois
tan can be made with fatty substances from which all the
glycerine has been removed. The evidence on this question,
however, is not quite conclusive.

In general, the procedure of the chamois tan is as follows:
The hydro-extracted, fleshed skins are rubbed on the flesh-
side with a good quality of seal-oil. They are then folded
up, and put into a ' kicker,' where they are tramped for
two or three hours to work in the oil. The kicker is a
machine such as shown in Fig. 8 consisting of a receptacle
for the skins, and two wooden hammers which work up
and down mechanically, turning and pounding the skins.
(As many as 1000-1500 skins of the size of musk-rats can
be worked at one time in such a machine.) The pelts are
then taken out and hung up in a warm room for several
hours, considerable oxidation taking place. Another coat
of oil is then applied, which is again tramped in, and the
skins are hung up once more and exposed to the air to
cause the oil to oxidize. After the skins are sufficiently
tanned they are rinsed in a weak soda solution to remove
the excess oil, washed and dried. When skins with fine hair
such as marten, sable, mink, etc., receive a chamois tan,
they are not tramped in kickers as the delicate top-hair
will be broken, and the value of the skin thereby reduced.

61

FUR DRESSING AND FUR DYEING

Instead they are placed in small drums, together with metal
balls of varying sizes and weights depending on the parti-
ular fur treated, and the oil is worked in by rotating the
drum. Such a ball-drum, as it is called, is shown in Fig. 9.

FIG. 9. BALL DRUM.

(F. Blattner, Brooklyn, New York.)

In conjunction with the chamois tan may be discussed
the process of oiling, inasmuch as the method of application
and the effect are both similar to the chamois tan up to a
certain point. It is customary to treat skins tanned by any
other method but the chamois process, with some oil in
order to render them more impervious to water. The great-
est variety of oils and fats can be used, the action in most
cases being simply the mechanical isolation of the skin
fibres by such a substance, thus corresponding to the first

62

TANNING METHODS

or physical phase of the chamois tan. The chemical phase,
if it takes place at all, is usually slight, and is merely in-
cidental. Oiling is generally applied either before drying
after tanning, or after drying, the oiled skins being placed
in a kicker and tramped to cause the oil to penetrate. In
some instances the oiling material is put in the same mix-
ture as the tanning chemicals, and the tanning and oiling
are effected simultaneously.

Among fatty substances used for oiling are mineral oils,
such as paraffine oil, and vaseline; animal fats, like train
oils, butter, egg-yolk, glycerine, neats-foot oil; vegetable
oils, like olive oil, castor oil, cottonseed oil; also sul-
phonated castor oil and sulphonated neats-foot oil. These
may be used singly or in various mixtures, an emulsion of
an oil and a soft soap also being frequently employed.

4. FORMALDEHYDE TANS

Formaldehyde has proven to be of great value in the tan-
ning of furs, usually in conjunction with other processes.
Formaldehyde is a gas with a strong, irritating odor, and its
40% solution, which is the customary commercial form, also
possesses this quality. When skins are treated for several
hours with a very dilute solution of the commercial product,
a leather is obtained which combines the properties of the
alum tan and the chamois tan. Moreover, in the majority
of observed cases, where furs have been tanned with for-
maldehyde, the skins seem to acquire a certain immunity
to the attacks of vermin and moths. Although the skins do
not in any way retain the odor of the formaldehyde, never-
theless these destructive agents seem to be repelled.

Numerous processes have been devised which use for-
maldehyde in connection with other substances for tan-
ning. Thus in a German patent is described a method in-
volving the alternate or simultaneous treatment of pelts
with solutions of formaldehyde and alpha or beta naphthol.

63

FUR DRESSING AND FUR DYEING

Both the formaldehyde and the naphthol exercise tanning
actions, but the process is not used in practise.

In 1911, Stiasny, a well-known leather chemist produced
a synthetic substance by the condensation of formaldehyde
with a sulphonated phenol, forming an artificial tannin.
This chemical, called " Neradol D," exhibits many of the
properties characteristic of true tannins, although in no
way related by structure and composition. By the use of
" Neradol D " a soft, white and flexible leather is obtained,
and it is therefore a suitable tanning material for furs.

5. COMBINATION TANS

In many instances more than one method is employed in
tanning the furs, and in this way what is known as a com-
bination tan is produced. While the various individual
processes described give more or less satisfactory results by
themselves, they generally possess some features, which for
certain purposes may be undesirable, and which can be elim-
inated or considerably reduced by using other processes at
the same time or subsequently. Some of the combination
methods are, pickle with chrome tan, alum tan with chrome
tan, and formaldehyde tan with pickle, mineral tan or
chamois tan. By means of such combinations various
qualities of tanned furs can be obtained, and if it is desired
to produce a pelt having certain special characteristics, this
can be brought about by combining two or more standard
methods.

Some illustrations of combined tannages are the follow-
ing: Alum-chrome tan. The skins are tanned by the regular
alum process, then the constituents of the chrome tan are
dissolved directly in the same bath, and the chrome tan is
effected as usual. Chrome-formaldehyde tan. To the regu-
lar chrome tan solution is added -|lb. of formaldehyde for
every 10 gallons of chrome liquor. The rest of the process
is as ordinarily.

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TANNING METHODS

6. VEGETABLE TANS

In practise, the vegetable tanning matters are not used
for furs, although in some special instances gambier cutch
may be employed occasionally with some other tan. How-
ever, many of these tannins also have dyeing properties,
and are used in dyeing the furs. In this connection it must
be mentioned that furs dyed with these materials also re-
ceive a vegetable tan, which improves the quality of the
leather to a considerable extent.

Comparison of The Various Tanning Methods

fin choosing a method for tanning any particular kind of
fur, several factors must be considered. The nature of the
pelt, insofar as it is weak or strong; the time, labor and
cost of materials required by the tanning process ; the effect
on the leather of the different dyes and chemicals used in
dyeing, if the skin is to be dyed, are a few of the points re-
quiring attention and consideration^)

For furs which are only to be dressed, a simple tan like
the pickle will suffice in most cases) Special instances, such
as the rabbit and mole already mentioned, and a few other
furs are tanned by the alum method. The pickle is un-
doubtedly the cheapest and simplest method of tanning
skins, and yields a soft, white leather which is permanent
as long as it is kept dry. If it is put into water, about 25%
of the salt contained within the pelt dissolves out, and the
acid present swells up the tissues. If the skin is dried in
this condition, it will come out hard and brittle, tending to
crack very easily. By treating the leather before drying with
a strong salt solution, a good deal of the extracted salt will
be replaced, and on drying and stretching, it will work out
soft. Skins tanned by the " Schrot-beize " are affected by
water in quite the same manner as the pickled skins.

The alum tan gives a leather similar to that produced by

65

FUR DRESSING AND FUR DYEING

the pickle, but with the advantage that the skins possess
greater stretch and flexibility. In its resistance to water,
the alum-tanned pelt is quite as susceptible as the other.
As a general rule, the skin absorbs about 6% of its weight
of alum from the tanning solution, but gives up three-
quarters of this when it is soaked in water, produc-
ing on drying, a hard, stiff leather. The chrome tan is
especially impervious to water, easily resisting temperatures
of 80 C, and even boiling water. It is employed to only a
limited extent on account of the special effort and care re-
quired to obtain satisfactory results, also because the pelt
acquires a pale blue-green color which is not desired on
dressed skins. The chamois tan, and some of the combina-
tions of the formaldehyde tan with the other methods, give
very soft, flexible leathers which possess a sufficiently great
resistance to the effects of water and heat.

In tests made to determine the best working tempera-
tures for dyeing skins dressed by the salt-acid tan, and for
skins dressed by the chamois process, some very interesting
facts were brought out. These two tans were chosen be-
cause they represent opposite extremes, the salt-acid tan
usually giving the poorest results/ and the chamois tan
giving the best results in practise in dyeing; Other
methods, except the chrome, range between these two. The
procedure in these experiments was to treat the skins at
ordinary temperatures in water, or dilute solutions of the
various chemicals and dyes usually employed in dyeing,
and then heat these solutions until the leather just began
to shrink and shrivel up. This point, called the shrinking
point (S.P.), gave the temperature to which the skins could
be subjected in the given solution without danger to the
pelt. (The experiments and observations were made by
Erich Schlottauer, while director of a large German fur
dressing and dyeing plant).

The first observation made was that different furs tanned
by the same process were affected differently in the same

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TANNING METHODS

solutions. Thus in plain water, three furs, all tanned by the
acid-salt tan, had shrinking points varying by several de-
grees; similarly with two different furs tanned by the
chamois process, there was a variation in the shrinking
point of two degrees. The explanation of this discrepancy
among the different skins may be that there was a slight
difference in the conditions under which they were tanned,
experiments showing that a maximum difference of 4C,
may exist among skins tanned by the same process, but
not under the same or identical circumstances. Another
reason for the variation may be the fact, that some skins
are more greasy than others, and are thus more resistant
to the effects of water or of some chemicals. The furs with
the higher shrinking points in water were those which
naturally are more greasy than the others.

Weak solutions of acids tend slightly to lower the shrink-
ing point, while weak solutions of alkalies appreciably
raise it, in both chamois-tanned and salt-acid-tanned skins.
Solutions of dyes and mordants as a general rule increase
the resistance of the skin to heat, varying quantities of
these substances having no, or little different effects on the
shrinking points. Previous treatment of the leather with
some oil considerably raises the shrinking point of the
pelt. Formaldehyde effects a great increase of the resist-
ance of the skins to heat, especially with chamois-tanned
furs. The experiments in this case were made by first treat-
ing the skins in the weak formaldehyde solution, and then
determining the shrinking point in plain water.

Two skins, both dressed by the " Schrot-beize," a Persian
lamb and an astrachan, after dyeing had shrinking points
almost 10 degress higher than when undyed. The extra
tannage which the skins received from the tannins used in
the dye mixtures for these furs, accounts for this increased
resistance to heat.

The following tables give the observed figures in the
different experiments:

67

FUR DRESSING AND FUR DYEING

TABLE I

A

S.P.

B

S.P.

C

S