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-The Project Gutenberg EBook of Principles and Practice of Fur Dressing and
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-Title: Principles and Practice of Fur Dressing and Fur Dyeing
-
-Author: William E. Austin
-
-Release Date: January 28, 2013 [EBook #41938]
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+*** END OF THE PROJECT GUTENBERG EBOOK 41938 ***
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-The Project Gutenberg EBook of Principles and Practice of Fur Dressing and
-Fur Dyeing, by William E. Austin
-
-This eBook is for the use of anyone anywhere at no cost and with
-almost no restrictions whatsoever.  You may copy it, give it away or
-re-use it under the terms of the Project Gutenberg License included
-with this eBook or online at www.gutenberg.org
-
-
-Title: Principles and Practice of Fur Dressing and Fur Dyeing
-
-Author: William E. Austin
-
-Release Date: January 28, 2013 [EBook #41938]
-
-Language: English
-
-Character set encoding: ISO-8859-1
-
-*** START OF THIS PROJECT GUTENBERG EBOOK FUR DRESSING, FUR DYEING ***
-
-
-
-
-Produced by Chris Curnow, Rosanna Murphy and the Online
-Distributed Proofreading Team at http://www.pgdp.net (This
-file was produced from images generously made available
-by The Internet Archive)
-
-
-
-
-
-Transcriber's Note: Italic text is denoted by _underscores_ and
-bold text by ~tildes~. Subscripted text is enclosed in {braces}.
-
-
-
-
-FUR DYEING AND FUR DRESSING
-
-
-
-
-                  PRINCIPLES AND PRACTICE
-                            OF
-                FUR DRESSING AND FUR DYEING
-
-
-                            BY
-                  WILLIAM E. AUSTIN, B.S.
-          CONSULTING CHEMIST TO THE FUR INDUSTRY
-
-
-                       _ILLUSTRATED_
-
-
-                      [Illustration]
-
-
-                         NEW YORK
-                  D. VAN NOSTRAND COMPANY
-                    EIGHT WARREN STREET
-                           1922
-
-
-                    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 dyeing 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 dressing and dyeing of furs.
-Even among members of other branches of the fur trade, there is very
-little accurate information on the subject. Real knowledge concerning fur
-dressing and dyeing is possessed only by those actually engaged 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 dressing 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. 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
-developments, 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 chemistry, since it will be an
-introduction into a field of applied chemistry, about which very little
-is known to those outside of the industry.
-
-Thanks are due to Dr. L. A. Hausman, of Cornell University, 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.
-
-
-
-
-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
-        relative 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
-        organizations 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
-        operations 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.
-
-
-    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 mordants.
-        Iron mordants. Copper mordants. Chromium mordants. 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
-        materials. The tannin substances. Logwood. Fustic.
-        Brazilwood. 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 Oxidation color. Range of shades obtainable.
-        Mordants. Procedure 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
-
-
-
-
-FUR DRESSING AND FUR 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 considered: 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 accessories, 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 subjected 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 operations 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 dresser
-and the fur dyer in addition to the technical knowledge and experience
-which are the fundamental requisites of the industry, also to have more
-than a superficial familiarity 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 almost
-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 considerably 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 called a pelt, or sometimes, in the case of large
-animals, a hide. The pelt, after having been dressed and dyed, is called
-a fur, the skin part being referred to as the leather, 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 increases 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 Siberian hare, are found only in the
-northern lands. An exception 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 known 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 correspondingly lower temperatures,
-have thicker and finer hair than those living nearer sea-level. A cold
-winter generally produces fur of high quality and fine color, a mild
-winter may 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. Animals 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 too tender to be fit for use. In certain
-cases, particularly the baby lambs, very young skins are especially
-prized, and 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 becomes 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 begins 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.
-
-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
-sections of the skin.
-
-Furs do not have differences confined to the hair part only; the leather
-also presents considerable variation among the different fur-bearing
-animals, especially in regard to the weight and thickness. The durability
-of furs, relatively considered under similar conditions of wear, also
-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 of Fur_             _Durability_    _Wt. in oz.
-                                     _Otter = 100_   per sq. ft._
-  Astrachan                                10           3
-  Bear, brown or black                     94           7
-  Beaver, natural                          90           4
-  Beaver, plucked                          85           3-7/8
-  Chinchilla                               15           1-1/2
-  Civet cat                                40           2-3/4
-  Coney                                    20           3
-  Ermine                                   25           1-1/4
-  Fox, natural                             40           3
-  Fox, dyed black                          25           3
-  Genet                                    35           2-3/4
-  Goat                                     15           4-1/8
-  Hare                                     05           2-1/4
-  Krimmer                                  60           3
-  Kolinsky                                 25           3
-  Leopard                                  75           4
-  Lynx                                     25           2-3/4
-  Marten, Baum natural                     65           2-3/4
-  Marten, Baum blended                     45           2-3/4
-  Marten, Stone natural                    45           2-7/8
-  Marten, Stone dyed                       35           2-7/8
-  Mink, natural                            70           3-1/4
-  Mink, dyed                               35           3-1/4
-  Mink, Jap                                20           3
-  Mole                                     07           1-3/4
-  Muskrat                                  45           3-1/4
-  Nutria, plucked                          25           3-1/4
-  Opossum, natural                         37           3
-  Opossum, dyed                            20           3
-  Opossum, Australian                      40           3-1/2
-  Otter, land                             100           4-1/2
-  Otter, sea                              100           4-1/2
-  Persian lamb                             65           3-1/4
-  Pony, Russian                            35           3-1/2
-  Rabbit                                   05           2-1/4
-  Raccoon, natural                         65           2-1/4
-  Raccoon, dyed                            50           2-1/2
-  Sable                                    60           2-1/2
-  Sable, blended                           45           2-1/2
-  Seal, fur                                80           3-1/2
-  Seal, fur dyed                           70           3-1/8
-  Skunk, tipped                            50           2-7/8
-  Squirrel, grey                           20-25        1-3/4
-  Wolf, natural                            50           6-1/2
-  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,
-condition 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, lightness 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 tend to decrease the number of
-available pelts of any particular animal, such as pestilences, gradual
-extermination due to excessive trapping, prevention of trapping, by
-protective 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 beautiful and rare, such as Russian
-sable or chinchilla, are practically 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 depreciate in value.
-
-A detailed description of the various furs used in commerce is not within
-the scope of this work, because such an account rightly belongs in a book
-on zoölogy. However, it is desirable that the reader who is interested
-in the dressing and dyeing of furs should have at least a passing
-acquaintance with the chief furs used in commerce, together with such of
-their individual characteristics as are of importance. The figures given
-are for the average dressed skin.[1]
-
-  [1] Descriptions after W. S. Parker, Deputy Chairman, Fur Section of
-      London Chamber of Commerce, in Encyclopedia Britannica, 11th Ed.
-
-~Astrachan~, see Lambs.
-
-~Badger.~--2 × 1 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 occasionally but is
-mostly used natural. Badger hair is very extensively used for 'pointing.'
-
-~Bear, Black.~--6 × 3 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 smaller, and the hair is finer, softer, and
-lighter-pelted. The best skins are from Canada.
-
-~Bear, Brown.~--6 × 3 ft. Similar to the Black Bear, but more limited in
-number. The color ranges from a light yellow 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 × 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 × 2 ft. 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 suitable furs are now used.
-
-~Broadtail~, see Lambs.
-
-~Caracul~, see Lambs.
-
-~Cat, Civet.~--9 × 4-1/2 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 × 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 × 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
-certain period. The fur is of a delicate blue-grey, with black shadings,
-the fur being 1 - 1-1/4 inches deep. Unfortunately, the skin is quite
-perishable.
-
-~Chinchilla, La Plata.~--9 × 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 × 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 × 2-1/2 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 × 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 × 3 inches. It is of the marten species, and its common name
-is polecat. The under-hair is yellow and 1/3 of an inch deep. The top-hair
-is black, 1-1/2 - 1-3/4 inches long, very fine and open in growth, and not
-so close as the martens. The largest and best skins are from Denmark,
-Holland and Germany. The Russian skins are smaller, silkier, and are
-usually dyed as a substitute for sable.
-
-~Fox, Blue.~--24 × 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 are more silky and of a smoky bluish color, and being scarce are
-most valuable. The white foxes which are dyed a smoky blue are brilliant
-and quite unlike the browner shades of the blue-fox.
-
-~Fox, Cross.~--20 × 7 inches. The skins generally have a pale yellow or
-orange tone, with some silver points, and a darkish cross marking on the
-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 × 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 × 6 inches. The under-hair is short and soft, as is also
-the top-hair, 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 × 8 inches, although some kinds are larger. The under-hair
-is long and soft, 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 × 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
-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 × 7 inches. It is usually small and inhabits the extreme
-northern sections of Hudson Bay, Labrador, 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.~--8 × 3-1/2 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; occasionally it is dyed.
-
-~Hare.~--24 × 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
-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 being 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.~--12 × 2-1/2 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 × 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 × 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 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 × 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 × 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.~--3 × 6 feet long. There are several kinds, the chief being the
-snow leopard or ounce, Chinese, Bengal, Persian, East Indian, and African.
-The first variety inhabits the Himalayas, and has a deep, soft fur, quite
-long as compared 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 × 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 Sweden. They are generally dyed black or brown,
-similar to dyed fox.
-
-~Marmot.~--18 × 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 × 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 × 5 inches. It is of a woolly nature 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 × 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 Japanese sorts are so pale that they are
-always dyed.
-
-~Mole.~--3-1/2 × 2-1/2 inches. Is plentiful in the British Isles and
-Europe, and is much in demand on account of its velvety 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 × 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 × 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
-under-hair, with very little silky top-hair, and silvery-white sides,
-presenting altogether a marked effect.
-
-~Nutria.~--20 × 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 × 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 is found in central sections of the United States, and is
-frequently dyed imitation skunk.
-
-~Opossum, Australian.~--16 × 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, 7 × 4 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 × 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 × 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 × 25 inches. Is one of the most beautiful 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-white
-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 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 × 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 Australia. The color ranges from white to black. France,
-Belgium 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 × 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 - 1-1/2 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 × 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 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 × 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 1-1/2 to 2-1/2 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, particularly 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 × 15 inches to 15 × 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 regions. The dressing and dyeing of seal takes longer
-than for 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 × 8 inches. The under-hair is full, and
-fairly close, with glossy, flowing top-hair about 2-1/2 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 × 5 inches. This size refers to the Russian and Siberian
-types, which are practically the only kind imported 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 × 25 inches. Is closely allied to the dog family, and very
-widely distributed over the world. The 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 × 18 inches. Is a native of America, Siberia, Russia, and
-Scandinavia, and is of the general nature of the bear. The under-hair is
-full and thick, with strong, bright top-hair about 2-1/2 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, Koala or Australian Bear.~--20 × 12 inches. It has a light grey
-or brown, close, thick under-hair 1/2 inch deep, and no top-hair, with a
-rather thick, spongy pelt. It is cheap, and well suited for rough wear.
-
-
-
-
-CHAPTER II
-
-STRUCTURE OF FUR
-
-
-Fur is made up of two main components, the hair and the skin, and each of
-these has a very complex structure.
-
-In the living animal the skin serves as a protective covering, and also
-constitutes an organ of secretion and of feeling; consequently it is
-of a highly complicated nature. The skin of all fur-bearing animals is
-essentially the same in structure, although varying considerably as to
-thickness and texture. It consists of two principal layers, which are
-entirely different in structure and purpose, and correspondingly different
-in both physical and chemical respects: the epidermis, epithelium or
-cuticle, which is the outer layer, and the dermis or corium, which is the
-true skin. (Fig. 1A).
-
-The epidermis is very thin as compared with the corium. Its outer layer
-consists of a tissue of cells, somewhat analogous to the horny matter
-of nails and hair. The inner surface, called the 'rete malpighi,' rests
-on the true skin, and 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. It 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 a somewhat different nature from the fibres, the coriin.
-Towards the center of the skin, the texture of the interweaving fibres
-is looser, becoming much more compact at the surface 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 surface next to the
-flesh is also closer in structure than the middle portions of the skin,
-and has somewhat of a membranous 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 the flesh 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 animal, 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,
-surrounds 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 structure as the
-skin, and is made up of four distinct parts. (Fig. 1B).[2]
-
-  [2] Descriptions and figures taken from "Mammal Fur Under the
-      Microscope," by Dr. L. A. Hausman, in _Natural History_,
-      Sept.-Oct., 1920.
-
-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.
-
-Surrounding the medulla is the cortex, which is made up of spindle-shaped
-cells fused into a horny, almost homogeneous, transparent mass, and
-forming a large proportion of the hair shaft.
-
-In the majority of the fur-bearing animals, there is distributed within
-and among the cells of the cortex a pigment in the form of granules or
-minute particles, arranged in the different hairs in fairly definite and
-characteristic patterns. It is to these pigment granules that the color
-of the hair is due primarily. In some cases the coloring matter of the
-shaft is uniformly diffused and not granular.
-
-[Illustration: FIG. 1
-
-_A._ STRUCTURE OF SKIN.
-
-_B._ STRUCTURE OF HAIR.]
-
-The outermost coat of the hair, or cuticle, is composed of thin,
-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. Since lustre 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
-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-section 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 protective 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, and varying so
-greatly in physical structure, both the skin and the hair belong to
-the same class of chemical compounds, 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 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.
-
-[Illustration: FIG. 2
-
-_A._ HAIR OF EUROPEAN BEAVER.
-
-_a._ TOP-HAIR. _b._ UNDER-HAIR.
-
-_B._ HAIR OF SKUNK.
-
-_a._ TOP-HAIR. _b._ UNDER-HAIR.]
-
-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 epidermis, and the walls of the cells of
-the inner layer of the 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, forming 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, vegetable
-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
-become stiff, horny and translucent. The mucines are also constituents of
-the cells of the 'rete malpighi.' The solubility 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 keratins of the hair and epidermis
-cells. On cooling, the solution solidifies to a jelly of gelatine. It
-combines with both acids and alkalies. A property of the skin which is
-of importance 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 solutions, the skins swell up less, while more of the skin
-substance dissolves, and by prolonged action of strong acids or alkalies,
-an almost complete solution of the skin is obtained, 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 increases
-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 epithelium 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 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 formation of ammonia and amino-acids.
-Ammonium 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. Calcium 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, are absorbed 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.
-
-
-
-
-CHAPTER III
-
-FUR DRESSING
-
-INTRODUCTORY AND HISTORICAL
-
-
-Fur dressing has a twofold purpose. First of 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
-decomposition. Having taken measures to assure the endurance or relative
-permanency of the pelt, the prime consideration 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 relatively unimportant, since
-it is not seen after the furs are made into garments. There 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 employment 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 appearance of the hair, and the leather is of
-secondary importance, in the production of leather, the hair plays no part
-at all, since it is entirely removed from the pelt. The fundamental points
-of resemblance between leather manufacture 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, ornament, 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 suitable 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." Numerous other biblical references indicate the use
-of animal skins for various purposes, sometimes prepared as leather,
-with the hair removed. Among the Egyptians tanning seems to have been
-a common 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-producing
-processes of the Egyptians are quite unknown, numerous figures engraved in
-stone afford an indication to 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 sarcophagi, 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 Assyrian, Phoenician
-and Persian origin, tends to show that these peoples also possessed a
-considerable degree of proficiency in tanning. Frequent references in the
-Greek literature 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
-excelled by any dressed with more modern processes and tanning methods.
-
-The next step forward in the preparation of animal skins 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 processes 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 vegetable 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 plants
-which possessed the highest content of active ingredients, 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 tanning, the methods
-probably differing in each country. Thus the Chinese, Syrians, and much
-later, the Moors, were each known 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 centered 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 supremacy, historical records
-show that the furriers, who did 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 beginning 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 association
-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 beginning of the
-nineteenth century, the guild system became ineffective, but the
-furriers continued their work as heretofore. 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 himself, 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 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.
-
-
-
-
-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 attached 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 overheat 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 the head off the body like a glove, trimming carefully about the
-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 without wrinkling. The pelts, after drying
-in a dry, airy place, are removed from the stretchers and are ready for
-the market. 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 operations 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 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 derived 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
-animal 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
-modified 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 and fatty tissues adhering to
-it, and the hair is generally soiled and occasionally blood-stained. In
-order to get the 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, although 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.
-
-[Illustration: FIG. 3. BEAM.]
-
-[Illustration: FIG. 4. KNIVES USED IN FUR DRESSING.]
-
-The first step in softening the skins is to get them thoroughly 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 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, continue as soon as the pelt is again moistened. The progress
-of decay causes the evolution of certain gases, the simplest of which
-is ammonia, 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 solution of 1/4% 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
-preservative 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
-soft and flexible. Sometimes 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 for several
-hours, or overnight. Another method which is practised with certain types
-of skins is the use of wet sawdust or of sawdust moistened with salt
-water. The fur skins are either embedded in the sawdust or drummed with
-it for several hours, or until sufficient moisture has been absorbed
-to render them flexible. By this means there is no danger of the skins
-being over-soaked, or of the hair being loosened. When the skins 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. Other 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 effective. The cleansed skins are then
-thoroughly rinsed to remove 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 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.
-The inner surface of the basket can also be enamelled or otherwise made
-resistant to the action of acids or other chemicals.
-
-[Illustration: FIG. 5. CENTRIFUGAL MACHINE.
-
-(_Fletcher Works, Inc., Philadelphia_)]
-
-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 expose the corium, enabling the efficient action of the chemicals
-used in the tanning processes. The process of removing this undesirable
-layer from the flesh-side is known as fleshing. 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. 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 are placed on the beam, and
-fleshed with a fleshing or skiving 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 suitable 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 regulating 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 difficulties, 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 occasionally met by the fur dresser,
-the skins after being soaked, 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 applied to the
-skins, thereby causing a swelling action to set 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.
-
-[Illustration: FIG. 6. FLESHING KNIFE ON BENCH.]
-
-[Illustration: FIG. 7. FLESHING MACHINE.
-
-(_Turner Tanning Machinery Co., Peabody, Mass._)]
-
-
-
-
-CHAPTER V
-
-FUR DRESSING
-
-TANNING METHODS
-
-
-After the pelts have gone through the preliminary operations of softening,
-washing and fleshing, they are ready to receive the treatment which
-will convert the easily decomposing skin into leather of 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 problem of leather formation.
-Numerous theories as to the nature 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. Procter, 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.... 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 substance 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 evaporated, left a thin fatty
-covering on the fibres which completely 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 matters, 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
-evaporates. 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 otherwise, but merely to isolate and coat them
-with water-resisting 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 insoluble and nonadhesive.
-
-"Before Knapp's work, the prevalent theory, at least as regards vegetable
-tannage, had been a chemical one, started 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 proportions of its constituents were
-considerably varied by changes in the strength of the solutions, or by
-washing the precipitate with hot water; and further, that in chemical
-compounds, 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 guncotton 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 substances,
-chemical reactions are rarely complete, but that stable positions are
-reached, so-called 'equilibria,' in which the proportion of changed and
-unchanged substance is dependent on concentration or other conditions;
-and that therefore such a precipitate might well be a mixture of gelatine
-with a true gelatine tannate from which further portions 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 substance. Nevertheless, these particles have many molecular
-properties, possessing plus or minus electrical charges; behaving like
-large ions under the influence of an electrical current; and mutually
-precipitating and neutralizing each other when positive and negative
-are brought together. Such solutions are called '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 '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 processes, 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 presence 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
-somewhat less rigorous standard of conditions to fulfil is satisfactory
-for the general needs and purposes of furs. The chief qualities which
-tanned furs must possess, with particular reference to the leather side of
-the pelt, are retention 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 operation 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 tanning 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 1/2 - 3/4 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 depending on the thickness of the skins. When the corium 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 skin
-may be considered 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 1/4%
-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 solution 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 turning the skins
-hair-side inward, they are laid flat together in pairs 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 particles
-adhering to the flesh-side. This operation is continued 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 manner: 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
-cannot 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 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
-bacteria attack solid substances from which they obtain their nourishment,
-but this is done in an indirect way, by secreting 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 property of bringing
-about the chemical change of an almost indefinite 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 chemical
-changes, particularly inducing fementations. 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 furfuris 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
-production of lactic acid. In both cases, the acids as they form swell
-and loosen up the skin fibres slowly, the salt penetrating 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 advantage 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 the grains of the tan, aside from their tanning action, contributing
-to the fullness and softness of the leather. There is also less likelihood
-of the leather being subsequently affected 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 considerably 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
-industry 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 endowed with the quality of converting skin
-to leather under suitable conditions, chromium and iron being the most
-important metals in this connection. Chemically these metals all belong
-to the same group, and have properties which are very similar in many
-respects, the characteristic 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 normal 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 of 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 absorb 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 thousand 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
-aluminum sulphate are the chief compounds used for this tan. In recent
-years, the aluminum sulphate has to a considerable 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 equivalent amount of free acid. The
-reaction may be shown as follows:
-
-  Al{2}(SO{4}){3} + 2H{2}O = Al{2}(SO{4}){2}(OH){2} + H{2}SO{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 by the skin, probably attaching itself to some of the acidic groups
-contained in the skin substance, in a manner analogous 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 and quite useless condition. If to the
-solution of the aluminum 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 quantity 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 lbs. of alum and 3 lbs. 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 lbs. of alum and 3 lbs. of salt, dissolved
-in 8 gallons of water, and made into a paste by the addition of 4 lbs. 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 application 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 time for it to be absorbed, another
-application is given, rubbing 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 drying. They
-are left so until tanned, as shown by examination and test. They are then
-rinsed, hydro-extracted and dried, and after stretching and finishing, a
-soft, white, pliable leather is obtained.
-
-
-B. _Chrome Tan_
-
-By using chrome alum instead of ordinary alum, together 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 neutral
-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 addition 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.
-
-The chrome tan is used only to a limited extent in the tanning of furs,
-the method requiring very careful treatment 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 possesses great resistance to the action of water.
-
-Any salt of chromium, with either mineral or organic acids, can be used,
-but chrome alum is the one most commonly employed. If a skin is entered
-directly into a solution of a chrome salt made basic with an alkali, the
-precipitation 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 solution 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 lbs. of chrome alum are dissolved 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 1/2% solution containing 2/3% 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 practical use. The principle
-involved is identical with that of the preceding mineral processes.
-
-
-3. CHAMOIS TAN
-
-The chamois dressing, as previously noted, is undoubtedly 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 object of the fat was to coat the fibres of the skin,
-thus preventing 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 contradistinction 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 extent, 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 saponification, 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 degree are affected by contact with the air, due to the absorption
-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 on the basis of this phenomenon of absorbing oxygen from the
-air, those possessing this quality to a great degree being 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-drying 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.
-
-[Illustration: FIG. 8. TRAMPING MACHINE OR "KICKER."
-
-(_F. Blattner, Brooklyn, New York._)]
-
-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 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 drying
-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 tanning 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.
-Instead they are placed in small drums, together with metal balls of
-varying sizes and weights depending on the particular 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.
-
-[Illustration: 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 greatest
-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 or physical phase of the chamois tan.
-The chemical phase, if it takes place at all, is usually slight, and
-is merely incidental. 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 mixture 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 sulphonated 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 tanning 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 formaldehyde, 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, nevertheless these
-destructive agents seem to be repelled.
-
-Numerous processes have been devised which use formaldehyde in connection
-with other substances for tanning. Thus in a German patent is described
-a method involving the alternate or simultaneous treatment of pelts
-with solutions of formaldehyde and alpha or beta naphthol. 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 combination 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 eliminated
-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 following: 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
-regular chrome tan solution is added 1/2 lb. of formaldehyde for every 10
-gallons of chrome liquor. The rest of the process is as ordinarily.
-
-
-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. However, 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 receive a vegetable
-tan, which improves the quality of the leather to a considerable extent.
-
-
-Comparison of The Various Tanning Methods
-
-In 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
-requiring 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 undoubtedly 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 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, producing 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 required
-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 combinations 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 temperatures 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 because 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 solutions. Thus in plain
-water, three furs, all tanned by the acid-salt tan, had shrinking points
-varying by several degrees; 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 4° C. 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 shrinking 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 resistance of the skins to heat, especially with
-chamois-tanned furs. The experiments in this case were made by first
-treating 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 degrees 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:
-
-                  TABLE I
-  +-------------------+------+------+------+
-  |                   |  A   |  B   |  C   |
-  |                   | S.P. | S.P. | S.P. |
-  +-------------------+------+------+------+
-  |_Salt-acid Tan_    |  C.  |  C.  |  C.  |
-  |Australian Opossum |  46° |  58° |  45° |
-  |Marmot             |  45° |  50° |  42° |
-  |Skunk              |  47° |  56° |  43° |
-  |                   |      |      |      |
-  |_Chamois Tan_      |      |      |      |
-  |Mink               |  52° |  61° |  45° |
-  |Muskrat            |  50° |  58° |  42° |
-  +-------------------+------+------+------+
-    A--Water
-    B--Water plus 1% Ammonia (s.g. 0.910)
-    C--Water plus 1% Sulphuric acid (66°
-        Beaumé)
-
-                  TABLE II
-  +-------------------+------+------+------+
-  |                   |  A   |  B   |  C   |
-  |                   | S.P. | S.P. | S.P. |
-  +-------------------+------+------+------+
-  |_Salt-acid Tan_    |  C.  |  C.  |  C.  |
-  |Australian Opossum |  53° |  52° | 54°  |
-  |                   |      |      |      |
-  |_Chamois Tan_      |      |      |      |
-  |Mink               |  59° |  59° |  59° |
-  +-------------------+------+------+------+
-    A--1000 c.c. water plus 40 c.c.
-        Peroxide plus 5 c.c. ammonia
-    B--500 c.c. water plus 2 grams Ursol D
-        (Para-phenylene-diamine)
-    C--500 c.c. water plus 5 grams Ursol D
-
-                      TABLE III
-  +-------------------+------+------+------+------+
-  |                   |  A   |  B   |  C   |  D   |
-  |                   | S.P. | S.P. | S.P. | S.P. |
-  +-------------------+------+------+------+------+
-  |_Salt-acid Tan_    |  C.  |  C.  |  C.  |  C.  |
-  |Australian Opossum |  51° |  51° |  53° |  56° |
-  |                   |      |      |      |      |
-  |_Chamois_          |      |      |      |      |
-  |Mink               |  59° |  59° |  61° |  62° |
-  +-------------------+------+------+------+------+
-    A--500 c.c. water plus 5 grams ground
-        nut-galls
-    B--300 c.c. water plus 2 grams pyrogallic
-        acid
-    C--500 c.c. water plus 2 grams potassium
-        bichromate
-    D--Water, after treating leather with
-        rapeseed oil
-
-                      TABLE IV
-  +-------------------+------+------+------+------+
-  |                   |  A   |  B   |  C   |  D   |
-  |                   | S.P. | S.P. | S.P. | S.P. |
-  +-------------------+------+------+------+------+
-  |_Salt-acid Tan_    |  C.  |  C.  |  C.  |  C.  |
-  |Australian Opossum |  49° |  49° |  55° |  50° |
-  |                   |      |      |      |      |
-  |_Chamois Tan_      |      |      |      |      |
-  |Mink               |  59° |  67° |  69° |  70° |
-  +-------------------+------+------+------+------+
-    A--500 c.c. water plus 5 c.c. formaldehyde
-        for 1 hour
-    B--500 c.c. water plus 5 c.c. formaldehyde
-        for 12 hours
-    C--500 c.c. water plus 10 c.c. formaldehyde
-        for 3 hours
-    D--As in C, but treated with 500 c.c. water
-        plus 5 c.c. ammonia, instead of water
-        alone.
-
-            TABLE V
-  +-------------+------+------+
-  |             |  A   |  B   |
-  |             | S.P. | S.P. |
-  +-------------+------+------+
-  |             |  C.  |  C.  |
-  |Persian Lamb |  44° |  54° |
-  |Astrachan    |  47° |  55° |
-  +-------------+------+------+
-    A--Before dyeing
-    B--After dyeing
-
-As a result of these experiments it may be concluded that the maximum
-temperature for drying salt-acid tanned skins should be 40° C., while
-for chamois tanned skins the temperature may be permitted to reach 45° C.
-without any danger of the leather being affected. Moreover, in the case
-of pickled skins, the matter of extraction of the tanning agent, as well
-as that of the leather becoming "burned" may be effectively counteracted
-by brushing some oil or fat on to the leather side before dyeing the pelt.
-
-The shrinking points of skins dressed by the various tanning methods are
-constant within certain limits, depending on the nature of the skin and on
-the conditions of tanning, and it is possible by observing the shrinking
-point, in conjunction with other characteristics of a given pelt, to
-determine what method of tanning was used.
-
-
-
-
-CHAPTER VI
-
-FUR DRESSING
-
-DRYING AND FINISHING
-
-
-One of the most important operations of all the fur dressing processes is
-the drying of the skins. For even when all the previous steps have been
-successfully completed, there is still a great possibility of the skin
-being injured if the drying is not properly and carefully carried out.
-
-The essential requirements for good drying are proper temperature,
-uniformity and rapidity. The leather part of the fur cannot, in the
-moist state, resist temperatures exceeding about 45° centigrade, for when
-dried, the skin turns out hard and stiff, and cracks easily. The furs must
-therefore be dried at an initial temperature of 25° to 30° centigrade, and
-as the moisture is gradually removed, the temperature may be raised, for
-the less water that remains in the pelt, the less is the leather affected
-by the heat, and the more difficult is the removal of its aqueous content.
-
-If the drying process is not a uniform one, that is, if all the skins
-in a lot are not subjected to the same drying conditions, then after the
-drying has proceeded for a certain time, some skins may be quite dry while
-others are not, or there may be as many different degrees of dryness as
-there are skins drying. There is also the possibility of great variation
-in the amount of moisture removed from different parts of the same skin.
-Such a state of affairs requires an extra expenditure of time, labor
-and heat power in order to get the whole lot of furs into a more or less
-uniform condition. Moreover in some kinds of furs, especially those with
-thick skins, when the drying is not even, there is danger of the epidermal
-layer drying away from the corium, and subsequently peeling and cracking.
-Uniformity of drying requires the maintenance of a reasonably constant
-temperature equally distributed throughout all parts of the space where
-the drying is done, so that all the furs may be dried under the same
-conditions.
-
-Rapidity of drying is desirable not only because it is beneficial to
-the condition of the pelt, but also from the point of view of practical
-business economy. The space occupied by the drying should be as small
-as possible compatible with the volume of work, and with the efficiency
-of operation. Slow drying involves the use of much space to take care of
-all the skins to be dried, or an accumulation of pelts ready to be dried,
-neither of which conditions is efficient or desirable.
-
-It was formerly the general custom, still practised in some
-establishments, to dry the skins by hanging them up, leather-side out on
-lines in a large room or loft, the heat being usually supplied by steam
-pipes. Such a procedure occupied often as long as two or three days to
-get complete drying, involved a great deal of labor, and the results were
-far from uniform. In fact, in order to get the skins more nearly equable,
-it was necessary to subject them to an additional operation. This usually
-consisted of rotating the skins in a closed drum for several hours, the
-constant intermingling of the pelts in contact with each other causing
-any moisture left in them to be evenly distributed throughout the whole
-lot. The skins, by this process also are rendered somewhat softer and more
-flexible, but by drying under proper conditions the entire extra operation
-can be dispensed with, the furs coming out quite as soft and flexible
-without the drumming.
-
-A great improvement was the adoption of large fans to circulate the heated
-air in the loft, thereby approaching more nearly an even temperature.
-More modern devices have, however, been developed, whereby drying can be
-effected in the most uniform manner, with perfect control of temperature,
-and requiring the least possible consumption of space, time, labor and
-power. A typical arrangement consists of a large closed chamber, generally
-constructed of steel, and divided into several compartments each of which
-may be operated independently of the others. Air, heated over suitably
-located steam pipes to the required temperature, is forced through the
-various compartments by means of fans operated by power. The conditions
-may be varied in each compartment, as to temperature or humidity, both
-of which can easily be regulated, or all the compartments may be used
-together as one unit. The skins are hung up on rods or lines in the
-compartments, or on special frames for the purpose, which are then entered
-into the compartments and the doors shut. The dry, heated air is forced
-to pass over the skins, and takes up their moisture. At the further end
-of the drying chamber is another fan which removes the moisture-laden air
-after it has done its work. The drying is effected in from 6 to 24 hours,
-and all skins are obtained in the same condition, for the process is quite
-uniform and regular.
-
-Within recent years there has been evolved a highly efficient and
-economical drying equipment, based on a somewhat different principle
-than underlies any of the foregoing methods. The conveyor type of dryer,
-as it is called, is admirably suited to the needs of the fur dressing
-and dyeing industry, and is undoubtedly superior to any of the previous
-systems of drying furs, in that it affords an enormous saving of space,
-time, labor and power, and gives greater uniformity and presents better
-working conditions.
-
-[Illustration: FIG. 10. DIAGRAMMATIC VIEWS OF CONVEYOR DRYER. _a._ SIDE
-VIEW; _b._ END VIEW.
-
-(_Proctor & Schwartz, Inc., Philadelphia._)]
-
-The conveyor dryer consists essentially of a steel enclosure, through
-which the skins pass on horizontal conveyors. Where special insulation
-is necessary, asbestos panels are used to line the enclosure, making the
-dryer absolutely fireproof, and enabling the maximum utilization of heat.
-In the middle of the dryer are located the steam coils which furnish
-the heat, and in many instances exhaust steam can be used as the source
-of heat. Figure 10 shows diagrammatically the arrangement and operation
-of the conveyor type of dryer. The enclosure is divided into several
-compartments, in each of which a different condition of temperature and
-humidity is maintained, the temperature being closely and accurately
-regulated by an automatic control, and once the dryer has been set for
-any condition, all skins will be dried exactly the same, regardless of
-weather or season.
-
-[Illustration: FIG. 11. CONVEYOR DRYER.
-
-(_Proctor & Schwartz, Inc., Philadelphia._)]
-
-The skins to be dried are placed on poles which in turn are set on
-the horizontal conveyors as in Fig. 11. As the skins pass through the
-compartments, large volumes of air, heated to the required temperature
-over the steam coils, are circulated among the skins by means of the fans.
-Exhaust fans, properly placed, remove a certain quantity of moisture-laden
-air when it has accomplished its full measure of work. When the skins on
-the conveyors have passed the full length of the dryer, they are entirely
-dry, and are then removed from the poles. (Fig. 12). The time required
-for drying varies according to the nature of the fur from 1-2 hours to 6-8
-hours. In tests made to determine the relative efficiency of the conveyor
-type of dryer as against the old "loft" method, it was found that there
-was a saving of over 50% in power, and of 85% in floor space, as well as
-a great saving of labor, when the conveyor system was used, the number
-of skins dried in a given period of time being the same in both cases.
-The advantages of the new method are easily apparent, and the saving
-is sufficiently great with large lots of furs, to make an appreciable
-difference in the final cost of dressing.
-
-If the skins have been dried by a modern drying system they all come out
-in a uniform condition, and are ready to go on immediately to the next
-operation. If, however, a form of the "loft" method of drying has been
-used, it is customary to subject the skins to an additional process. The
-dried pelts are put in drums with damp sawdust, and drummed for a short
-time in order to get them into the proper condition. The drumming is
-essential for the purpose of equalizing the condition of the pelts, some
-being drier than others, and as a consequence of the contact with the
-moist sawdust, they are all brought to the same degree of dryness. As a
-result of this operation also, the skins become considerably softened.
-
-[Illustration: FIG. 12. DELIVERY END OF CONVEYOR DRYER.
-
-(_Proctor & Schwartz, Inc., Philadelphia._)]
-
-Then if the pelts have not been previously oiled during the tanning
-process, or prior to the drying, they receive this treatment now. The oil
-or fat is applied to the leather side of the furs, which are then placed
-in the tramping machine for a short time in order to cause the oil to be
-forced into the skin. The fibres of the corium thus become coated with a
-thin layer of fatty material, which contributes greatly to the softness
-and flexibility of the pelt, and increases its resistance to the action of
-water, and also, in certain instances a partial chamois tan is produced,
-thereby improving the quality of the leather.
-
-[Illustration: FIG. 13. STRETCHING MACHINE FOR CASED SKINS.
-
-(_Reliable Machine Works, Evergreen, L. I._)]
-
-The skins are now returned to the work bench, and subjected to the
-stretching or "staking" process. This consists in drawing the skin in all
-directions over the edge of a dull blade, which is usually fixed upright
-in a post with the edge up. Or, the stretching may be done on the fleshing
-bench, substituting a dull blade for the fleshing knife. Recently staking
-machines are being used in the larger establishments, the work being
-done much more quickly and efficiently. As a result of this operation,
-the leather becomes very soft and flexible, every bit of hardness and
-stiffness being eliminated, and the skins receive their maximum stretch,
-thereby giving the greatest possible surface to the pelage. This not only
-helps to bring out the beauty of the hair, but is also a decided advantage
-from the economic point of view, as a considerable saving of material
-is effected in this way, sometimes even to the extent of twenty-five per
-cent. Cased skins are stretched in a somewhat different manner, by means
-of stretching irons. These consist of two long iron rods joined by a pivot
-at one end. The skins are slipped on to the irons, which are then spread
-apart, and in this way the skins are stretched and softened. A machine
-which does this work very efficiently is shown in Fig. 13. The skin is
-drawn onto the stretching arms, in this case made of bronze, which are
-then forced apart by pressing on a pedal. When properly stretched to the
-maximum width in all directions possible, and thus thoroughly softened,
-the skin can easily be reversed, that is, turned hair-side out. As many as
-6000 skins can be stretched, or 4000 to 5000 skins stretched and reversed
-by one man in one day on such a machine.
-
-[Illustration: FIG. 14. FUR BEATING MACHINE.
-
-(_S. M. Jacoby Co., New York._)]
-
-The pelts are then combed and beaten. In smaller plants these operations
-are done by hand, but suitable machines are being employed. In order to
-straighten out the hair, it is combed or brushed. Then in order to loosen
-up the hair, and to cause it to display its fullness, the furs are beaten.
-This process is also done by hand in some establishments, but up-to-date
-places use mechanical devices for this purpose. A type of machine which
-has proven very successful, and is enjoying considerable popularity
-is shown in Fig. 14. These machines are also made with special suction
-attachments which remove all dust as it comes out of the beaten skin,
-thereby making this formerly unhealthful operation thoroughly sanitary
-and hygienic.
-
-The final process is drum-cleaning. This operation is intended
-specifically for the benefit of the hair part of the fur, and is very
-important inasmuch as the attractive appearance of the fur depends largely
-upon it. The drum, such as is shown in Fig. 15 is generally made of wood,
-or sometimes of wood covered with galvanized iron. The skins together with
-fine hardwood sawdust are tumbled for 2 to 4 hours, or sometimes longer.
-Occasionally a little asbestos or soapstone is added to the sawdust; for
-white, or very light-colored skins, gypsum or white sand is used, either
-alone, or in admixture with the sawdust; and for darker skins, graphite or
-fine charcoal is sometimes added in small quantities. The drum-cleaning
-process polishes the hair, giving it its full gloss and lustre, and at
-the same time absorbing any oil or other undesirable matter which may be
-adhering to the hair as a result of the washing and tanning processes.
-Any soap, or traces of mordant are wiped off and so removed, and by using
-heated sawdust, or heating the drum while rotating, the fur acquires a
-fullness and play of the hair which are great desiderata in furs. The
-sawdust must then be shaken out of the furs. This is done by cageing. In
-some instances, the drum itself can be converted into a cage, by replacing
-the solid door with one made of a wire screen. (Fig. 16.) Usually,
-however, the skins are removed from the drum and put in a separate cage,
-which is built like the drum, but has a wire net all around it, through
-which the sawdust falls, while the skins are held back. The cages are
-generally enclosed in compartments in order to prevent the sawdust from
-flying about and forming a dust which would be injurious to the health of
-the workers. In large establishments, the drum-cleaning machinery occupies
-a large section of the plant, many drums and cages being used, and special
-arrangements being made to take care of the sawdust which can be used over
-again several times, until it becomes quite dirty.
-
-[Illustration: FIG. 15. DRUM. (COMBINATION DRUM AND CAGE AS A DRUM.)
-
-(_F. Blattner, Brooklyn, New York._)]
-
-[Illustration: FIG. 16. CAGE. (COMBINATION DRUM AND CAGE AS A CAGE.)
-
-(_F. Blattner, Brooklyn, New York._)]
-
-With this operation ends the ordinary procedure of fur dressing. But
-there are several additional processes required in the treatment of
-certain furs, which are generally undertaken by the dresser, and chief
-among these are shearing and unhairing. Sometimes this work is done in
-separate establishments organized solely for this business. Certain kinds
-of furs, among them being seal, beaver and nutria, possess top-hair which
-may detract from the beauty of the fur, the true attractiveness being in
-the fur-hair. The top-hairs are therefore removed, and for this purpose
-machines are now being used. Formerly this work was all done by hand, and
-on the more expensive furs like seal and beaver, unhairing is now done on
-a machine operated by hand. The principle of the process is as follows:
-The skins are placed on a platform and the hair blown apart by means of
-a bellows. The stiff top-hairs remain standing up, and sharp knives are
-brought down mechanically to the desired depth, and the hair is cut off
-at that point. The skin is then moved forward a short distance, and the
-process repeated until all the top-hairs have thus been cut out. With
-muskrats, or other pelts which do not require such very careful attention,
-the whole process is done automatically on a machine. The fur-hair is
-brushed apart by means of brushes and a comb, and at regular intervals,
-sharp knives cut off the top-hairs. Several hundred skins can be unhaired
-in a day on such a machine requiring the attention of only one man. A
-machine for unhairing skins is shown in Fig. 17.
-
-[Illustration: FIG. 17. UNHAIRING MACHINE.
-
-(_Seneca Machine & Tool Co., Inc., Brooklyn, N. Y._)]
-
-With other furs, such as rabbits, hares, etc., where the trouble of
-unhairing would be too great commensurate with its advantages, the hair
-is sheared instead. The top hair is cut down to the same length as the
-under-hair by means of shearing machines which can be regulated to cut to
-any desired length of hair. A typical device for shearing furs is shown
-in Fig. 18.
-
-[Illustration: FIG. 18. FUR-SHEARING MACHINE.
-
-(_Seneca Machine & Tool Co., Inc., Brooklyn, N. Y._)]
-
-
-
-
-CHAPTER VII
-
-WATER IN FUR DRESSING AND DYEING
-
-
-The assertion has often been made, although its absurdity is now quite
-generally realized, that the success of the European fur dressers and
-dyers, particularly in Leipzig, is due to the peculiar nature of the
-water used, which is supposed to be especially suited for their needs.
-The achievements in this country in the fur dressing and dyeing industry
-during the past few years are ample and sufficient answers to the claim of
-foreign superiority in this field no matter what reason may be given, and
-particularly when the quality of the water used is advanced as a leading
-argument. For the water employed by the establishments in and about New
-York, as well as in other sections of the country is surely not the same
-as the water of Leipzig, yet the work done here is in every respect the
-equal of, if not better than the foreign products.
-
-It is interesting to note that similar rumors were current here in the
-early period of the development of the American coal-tar industry since
-1914. Our efforts to establish an independent dyestuff industry were
-doomed to failure, according to those who circulated the stories, because
-we did not have the water, which they claimed was responsible for the
-German success. The present status of the American dye business, in its
-capacity satisfactorily to supply most of the needs of this country and
-of others as well, speaks for itself.
-
-However, as is often the case with such erroneous assertions, there
-is just enough of an element of truth in the statement regarding the
-peculiar qualities of certain kinds of water, to make the matter worthy
-of consideration. Water is certainly a factor of great importance in fur
-dressing and dyeing, and it is not every sort of water that is suitable
-for use. This fact was recognized by the early masters of the art, for
-they invariably used rain-water as the medium for their tanning and dyeing
-materials, and their choice must be regarded as an exceedingly wise one.
-While the necessity for giving consideration to the quality of the water
-for fur dressing purposes is great, it is in fur dyeing that the effects
-of using the wrong water are largely evident, and so extra care must be
-exercised in the selection of water for this purpose.
-
-The essential requirements for a water suitable for the needs of the
-fur dressing and dyeing industry, are: first, a sufficient, constant
-and uniform supply; and second, the absence of certain deleterious
-ingredients. Chemically pure water is simply the product of the
-combination of two parts by volume of hydrogen with one part by volume
-of oxygen. Such water can only be made in the laboratory, and is of no
-importance in industry. For practical purposes, distilled water may be
-regarded as the standard of pure water. Here, too, the cost and trouble
-involved in the production of distilled water on a large scale is
-warranted only in a certain few industrial operations. A natural source
-of water which in its character most nearly approaches distilled water
-is rain. In fact, rain-water is a distilled water, for the sun's heat
-vaporizes the water from the surface of the earth forming clouds, which
-on cooling, are condensed and come down as rain. Rain-water is usually
-regarded as the purest form of natural water. Exclusive of the first
-rain after a dry period, rain-water is quite free of impurities, except
-possibly for a small percentage of dissolved atmospheric gases, which
-are practically harmless, and which can usually be readily eliminated
-by heating the water. Moreover, rain-water is quite uniform in its
-composition throughout the year in the same locality, and it possesses
-all the desirable qualities of a water suited for fur dressing and dyeing
-purposes. Formerly when the quantity of water used in the industry
-was comparatively small, the supply from rain was sufficient to meet
-all the requirements. But now, when tremendous quantities of water are
-used constantly, rain-water is no longer a feasible source, and other
-supplies must be utilized, although in a sense, all water may be traced
-to rain-water as its origin.
-
-When rain-water falls on the earth it either sinks into the ground until
-it reaches an impervious layer, where it collects as a subterranean
-pool, forming a well, or continues to flow underground until it finally
-emerges at the surface as a spring; or on the other hand the rain-water
-may sink but a short distance below the surface, draining off as ponds,
-lakes or rivers. In the first case the water is called ground water, in
-the latter it is known as surface water. Ground water usually contains
-metallic salts in solution, and relatively little suspended matter. If
-the water has percolated through igneous rocks, like granite, it may be
-quite free even of dissolved salts, and such water is considered "soft."
-If, however, the rocky formations over which, or through which, the water
-has passed contain limestone or sandstone, or the like, salts of calcium
-and magnesium will be dissolved by the water. The presence of the lime
-and magnesia salts, as well as salts of aluminum and iron, in the water,
-causes it to be what is termed "hard." Surface water is more likely to
-contain suspended matter, with very little of dissolved substances.
-Suspended matter, like mud, contains much objectionable matter such
-as putrefactive organisms and iron, but most of these materials can be
-removed by filtration or sedimentation, and seldom cause any difficulties.
-
-Hardness in water is generally the chief source of trouble when the water
-is at fault. Hardness may be of two kinds, either permanent, or temporary,
-or sometimes both are found together. Water which is permanently hard
-usually contains the lime and magnesia combined as sulphates. Temporary
-hardness, on the other hand, is due to the presence of lime and magnesia
-in the form of bicarbonates, the carbon dioxide contained in the water
-having dissolved the practically insoluble carbonates:
-
-   CaCO{3} + CO{2} + H{2}O = Ca(HCO{3}){2}
-   calcium   carbon  water      calcium
-  carbonate  dioxide          bicarbonate
-
-Temporary hardness can be eliminated by heating the water, the carbon
-dioxide being expelled and the carbonates of lime and magnesia being
-precipitated and then filtered off. Both permanently and temporarily hard
-waters can be softened by the addition of the proper chemical, such as
-an alkaline carbonate like sodium carbonate. This precipitates insoluble
-carbonates of the lime, magnesia, iron and aluminum, leaving a harmless
-salt of sodium in solution in the water. The sludge is allowed to settle
-in tanks before the water is used.
-
-In fur dressing and dyeing, water is employed for soaking and washing the
-skins, dissolving chemicals, extracts and dye materials, and also for
-steam boilers. A small amount of hardness in the water is not harmful,
-and up to 10 parts of solid matter per 100,000, may be disregarded.
-Permanent hardness is particularly objectionable in water for boiler
-purposes, as it forms scale. The effect of the impurities of the water
-depends on the nature of the chemicals and dyes used. Where acids are
-used in solution compounds of magnesium, lime and aluminum will generally
-not interfere. Hard water must not be used for soap solutions, as sticky
-insoluble precipitates are formed with the soap by the metals, this
-compound adhering to the hair, and being difficult to remove, will cause
-considerable trouble in subsequent dyeing. An appreciable loss of soap
-also results, as one part of lime, calculated as carbonate will render
-useless twelve parts of soap. In tanning or mordanting, where salts of
-tin, aluminum or iron are employed, hard water should not be used, as lime
-and magnesia will form precipitates with them. Bichromates will be reduced
-to neutral salts, and cream of tartar will also be neutralized. With dyes
-also, hard water has a deleterious effect. Basic dyes are precipitated by
-this kind of water, rendering part of the dye useless, and also causing
-uneven and streaky dyeings. Sometimes the shades of the dyeings are
-modified or unfavorably affected. Considerable quantities of lime and
-magnesia in the water will cause duller shades with logwood and fustic
-dyeings. The presence of iron, even in very slight quantities generally
-alters the shade, darkening and dulling the color.
-
-These facts were apparently all recognized and understood by the fur
-dressers and dyers of an earlier period, for instead of utilizing the
-water of lakes and streams near at hand, which afforded a more constant
-supply, but which contained harmful impurities, they collected the
-rain-water, which was always soft. Whether they realized the nature
-and character of the substances that make water hard is uncertain,
-but they were always careful to avoid such water. At the present time
-establishments located in and about large cities like New York, where
-the majority of American fur dressing and dyeing plants are situated,
-have no trouble about the water. The cities supply water which is soft,
-suitable alike for drinking and industrial purposes. Other plants, not
-so fortunately situated, often have to employ chemical means to treat the
-water so as to make it suitable for use.
-
-
-
-
-CHAPTER VIII
-
-FUR DYEING
-
-INTRODUCTORY AND HISTORICAL
-
-
-In discussing fur dyeing, the question naturally arises, "Why dye furs at
-all? Are not furs most attractive in their natural colors, and therefore
-more desirable than those which acquire their color through the artifices
-of man?" The answer cannot be given simply. Natural furs of the more
-valuable kinds are indeed above comparison with the majority of dyed furs.
-Yet there are several reasons which fully justify and explain the need
-for fur dyeing, for at the present time, this branch of the fur industry
-is almost as important and indispensable as the dressing of furs.
-
-The first application of dyeing to furs, had for its purpose the
-improvement of skins which were poor or faulty in color; or rather, the
-object was to hide such defects. As nearly as can be ascertained, this
-practise was instituted at some time during or before the fourteenth
-century, for fur dyeing seems to have been common during that period, as
-is apparent from the verses of a well-known German satirist, Sebastian
-Brant, who lived in the latter part of the fourteenth century:
-
-    "Man kann jetzt alles Pelzwerk färben,
-    Und tut es auf das schlechste gerben."
-
-However, at a later period, there was a general condemnation of the dyeing
-of furs, and among the list of members of the furrier's guilds, none can
-be found who are described as dyers. There is a record of a decree issued
-by a prince in a German city in the sixteenth century, prohibiting the
-practise of fur dyeing. Inasmuch as furs were worn only by the nobility
-and certain other privileged classes, and also were very costly, there
-was great profit to be had by dyeing inferior skins so as to disguise the
-poor color, and then selling such furs at the price of superior quality
-skins. This was undoubtedly the reason for the prohibitory decree, but
-there were some who continued to practise the forbidden art in secret,
-using secluded and out-of-the-way places for their workshops, and mixing
-their carefully-guarded recipes with as much mystery as the witches did
-their magic potions. These circumstances probably account for the great
-amount of mystery which has been, and still is to a considerable degree,
-attached to fur dyeing, and also explains the opprobrium and distrust with
-which fur dyers were formerly regarded.
-
-Even at the present time, dyeing is often employed to improve furs which
-are faulty in color. It frequently happens, that in a lot of skins there
-are some which are considerably off shade, or in which the color is such
-as to appreciably reduce their value below the average, the hair being
-usually too light a shade, or of uneven coloring. By carefully dyeing
-these skins of inferior color, they can be made to match very closely
-the best colored skins of the particular lot of furs, and consequently
-increase their value. With most of the cheaper kinds of furs, the trouble
-and cost of improvement by dyeing would not be worth while today; but with
-some of the more valuable furs, and especially such as are very highly
-prized, like the Russian sable, or marten, or chinchilla, the darkening
-of light skins by the skillful application of fast dyes to the extreme
-tips of the hair, will increase their value sufficiently to warrant the
-expense. This dyeing or "blending" as it is called in such cases, is done
-in such a clever and artistic manner that only experts can distinguish
-them from the natural. Dyeing used for such purposes is not objectionable,
-provided the skins are sold as dyed or "blended."
-
-There are certain kinds of furs, such as the various lambs, Persian,
-Astrachan, Caracul, etc., which are never used in their natural color,
-because it is usually of a rusty brownish-black. These are furs possessing
-valuable qualities otherwise, so they are dyed a pretty shade of black,
-which brings out the beauty of the fur to the fullest extent. Sealskins
-are also dyed always. Formerly they were dyed a deep, rich dark brown,
-resembling the finest shades of the natural color, but now the seals are
-dyed black with a brownish undertone, a color quite different from the
-natural. While these two instances cannot be said to be cases of dyeing
-to disguise faulty color, they are examples of improvement of color by
-dyeing.
-
-Closely associated with the use of dyes to increase the value of a fur
-by improving its color, is the dyeing of skins of a certain lot of furs
-to produce a uniform shade, thereby facilitating or to a considerable
-degree eliminating the task of matching the skins by the furrier. This is
-usually done only on skins which are quite small, of which a great many
-are needed in the manufacture of fur garments, because the matching of
-several hundred skins would entail too much time and labor commensurate
-with the value of the fur. The most notable instance of the use of dyes to
-produce a uniform shade on furs is the case of the moleskin. Occasionally,
-furs are dyed after being made into garments, by careful application of
-dyes, in order to obtain certain harmonious effects, such as uniformity
-of stripe, or to produce a desired gradation of shade among the different
-skins comprising the garment.
-
-Not infrequently, the great variety of shades and color schemes which
-Nature provides in the different furs, becomes insufficient to satisfy the
-desire of the fur-wearing public for something new. The whims of fashion
-always require some novel effect, even though it be for only one season.
-To meet this demand for novelty, fantasy or mode shades are produced on
-suitable furs,--colors which do not imitate those of any animal at all,
-but which, nevertheless, strike the popular fancy. It often happens that
-such a color becomes quite popular, and enjoys a considerable vogue, to
-the great profit of those who introduced the particular color effect. The
-best ones, however, meet with only a comparatively short-lived demand,
-being soon superseded by different color novelties.
-
-The basis, though, of the greatest proportion of fur dyeing at the present
-time, is the imitation of the more valuable furs on cheaper or inferior
-skins. With the gradual popularization of furs as wearing apparel since
-the beginning of the last century, the demand for furs of all kinds
-has increased enormously. The supply of furs, on the other hand, and
-especially of the rarer kinds, has had difficulty in keeping pace with
-the requirements, and as a result there is a shortage. A very effective
-means of relieving this shortage, to a great degree, at any rate, is
-the dyeing of imitations of the scarcer furs on cheaper skins. There
-are many animals among the more common, and more easily obtainable ones,
-whose skins are admirably suited as the basis of imitations of the more
-costly furs. Some of the furs which are adapted for purposes of dyeing
-imitations are marmot, red fox, rabbit, hare, muskrat, squirrel, opossum,
-raccoon, and many others, and the imitations made are those of mink,
-sable, marten, skunk, seal, chinchilla, etc., and indeed, there are very
-few valuable furs, which have not been dyed in imitation on cheaper pelts.
-On account of the general mystery which formerly surrounded fur dyeing
-establishments, and which has persisted to this day, although to a lesser
-degree, many peculiar notions were held, even by those in the fur trade,
-concerning the production of imitations. The idea that in order to "make"
-a certain fur out of a cheaper skin, it was necessary to use the blood
-of the animal imitated, is typical of the conceptions of fur dyeing held
-not so long ago. To-day, while the knowledge generally possessed about
-this branch of the fur industry is meagre and vague, the air of mystery
-and secrecy has become somewhat clarified, and such ideas as are current
-about fur dyeing are more rational than formerly.
-
-The dyeing of imitations is quite an artistic kind of work, and indeed
-fur dyeing ought to be classed among the finest of industrial arts. Some
-of the reproductions achieved by dyers on a commercial scale are truly
-admirable. The possibility of imitating the finer furs on cheaper skins
-naturally led to abuse, the dyed furs being passed off frequently on the
-unsuspecting and uninformed buyer as the genuine original. In fact, this
-practise became so flagrant that in England laws were enacted to remedy
-the evil. At the present time, dyed furs are all sold as such, although
-there always may be some unscrupulous merchants who seek to profit by
-deception. Some of the imitations and the names of the furs for which they
-were sold, are as follows:
-
-  Muskrat, dyed and plucked        sold as seal
-  Nutria, plucked and dyed         sold as seal
-  Nutria, plucked and natural      sold as beaver
-  Rabbit, sheared and dyed         sold as seal or electric seal
-  Otter, plucked and dyed          sold as seal
-  Marmot, dyed                     sold as mink or sable
-  Fitch, dyed                      sold as sable
-  Rabbit, dyed                     sold as sable
-  Rabbit, dyed and sheared         sold as beaver
-  Muskrat, dyed                    sold as mink or sable
-  Hare, dyed                       sold as sable, fox, or lynx
-  Wallaby, dyed                    sold as skunk
-  White rabbit, natural            sold as ermine
-  White rabbit, dyed               sold as chinchilla
-  White hare, dyed or natural      sold as foxes, etc.
-  Goat, dyed                       sold as bear, leopard, etc.
-
-This list serves to indicate but a few of the great number of
-possibilities which are available for the fur dyer to produce imitations
-of the better classes of furs. Needless to say, these imitations cannot,
-as a general rule, equal the originals, because while the color is one
-of the most important features in judging the fur, the nature of the
-hair, gloss, waviness, thickness, and also the durability are essential
-considerations, and it is only in certain instances that skins used
-for imitations approach the originals in these respects. However, for
-the purposes and desires of the majority of people who wear furs, the
-imitations are deemed quite satisfactory, and they also have the advantage
-of being cheaper than the natural originals.
-
-For whichever reason furs are dyed, there is no doubt that the art of fur
-dyeing is one of the most difficult kinds of application of dye materials.
-In the dyeing of the various textiles, either as skein or woven fabric,
-the material is of a uniform nature, and therefore the dye is absorbed
-evenly by the fibres. Moreover, textiles are dyed at, or near the boil,
-the dyestuff being more uniformly and permanently taken up from solution
-by the fibre at elevated temperatures.
-
-How different is the case with furs! Far from being homogeneous, furs
-present the greatest possible diversity of fibres to be dyed. As already
-noted elsewhere, fur consists of two principal parts, the hair and the
-leather, differing widely in their actions toward dyes. As a general
-rule, the leather absorbs dyestuffs much more readily than the pelage,
-and inasmuch as fur dyeing is intended mainly and primarily to apply to
-the hair, there is usually an appreciable loss of dye material due to its
-being absorbed by the leather, and thereby rendered unavailable for dyeing
-the hair. This fact must be taken into account in the dyeing of furs, and
-the methods must be adapted accordingly.
-
-With reference to the hair itself, not only has each class of furs
-hair of a different kind, but even in the same group there is always a
-considerable divergence in the properties of the hair. The fur-hair, being
-more or less of a woolly nature, takes up the dye with comparative ease,
-while the top-hair is quite resistant to the action of all dye materials.
-As pointed out in the discussion of the nature of fur, on different parts
-of the same pelt the hair varies in its capacity for absorbing coloring
-matters. The color of the hair, also frequently presents a great variety
-throughout the skin, both in fur-hair and top-hair. Yet with all this lack
-of uniformity and homogeneity, the dyed fur must be of an even color,
-closely approaching the natural, gently graded and without any harsh or
-unduly contrasted effects. The natural gloss of the hair, one of the most
-valuable qualities of the fur, must be preserved. This is by no means
-a simple matter, for the luster is affected by dyes and chemicals with
-comparative ease, and especially careful treatment is necessary to prevent
-any diminution of the gloss.
-
-When the leather part of the fur is exposed to solutions of a temperature
-exceeding 40°-50° centigrade, it soon shrivels up or shrinks, and on
-drying the pelt, becomes hard and brittle, and therefore quite useless.
-Methods of fur dyeing have to take into consideration this fact, and the
-temperature of the dyebath must not be greater than 35°-40° centigrade. To
-be sure, certain dressings make furs capable of withstanding much higher
-temperatures, but their applicability is not universal, being suited only
-for a very limited special class of dyestuffs. (V. Fur Dressing). The
-necessity for employing comparatively low temperatures, coupled with the
-great resistance of the hair to the absorption of dye, even at much higher
-temperatures, makes fur-dyeing a very difficult operation indeed. Another
-obstacle which must be surmounted, is the possibility of extraction by
-the dye solution, of those materials, chemical or otherwise, which are
-contained in the leather, and which are the basis of its permanence,
-softness and flexibility. For in the majority of dressing processes, the
-action of the ingredients is a preservative one, and when these are wholly
-or partially removed from the leather during the dyeing, it becomes, on
-drying, hard and horny, like the original undressed pelt. In cases where
-furs are to be dyed, special dye-resisting dressings must be used, or the
-dyed skins must receive an additional dressing before drying.
-
-Dyeings on furs, to have any value, must possess great fastness to light,
-rubbing and wear, and must not change color in time, either when the furs
-are stored, or when made up into garments. The necessity for fur dyeings
-to have these properties, together with the difficulties outlined above,
-has greatly limited the field of available dyeing materials, as well as
-the methods of application. These will now be taken up in detail.
-
-
-
-
-CHAPTER IX
-
-FUR DYEING
-
-GENERAL METHODS
-
-
-Before the furs can be dyed, they have to undergo certain preparatory
-processes: first, killing, which renders the hair more susceptible to the
-absorption of the dye; and second, mordanting, which consists in treating
-the killed fur with chemicals which help the dye to be fixed on the hair.
-Then the skins are ready to be dyed.
-
-There are two principal methods by which dyes are applied to furs in
-practise: the brush process, whereby only the tips or the upper part
-of the hair are colored; and the dip process, whereby the entire fur,
-including the leather is dyed. All other procedures in fur dyeing
-are modifications or combinations of these two. Killing solutions and
-mordanting solutions are also applied by one of these methods, usually
-the dip process, although very frequently combinations of the brush and
-dip methods are used.
-
-Chronologically the brush method of dyeing came first. The early masters
-of the art were extremely fearful about employing any means by which
-there was a possibility of the leather being in any way affected. They
-naturally had to devise such methods as would give the desired effect
-in a satisfactory manner, and as would be confined solely to the hair
-part of the fur, leaving the leather untouched. By applying the dye
-or other material to be used, in the form of a paste with a brush, the
-upper portion of the hair only was treated. For different kinds of furs
-different sorts of brushes were used, and the depth to which the hair was
-colored could be controlled by skillful manipulation of the brushes. It
-was frequently necessary to give a ground color to the hair, the lower
-part being dyed a different shade from the tips. This was accomplished
-by spreading the dye paste over the hair with a broad brush, and then
-beating the color in with a specially adapted beating brush. With larger
-furs, two skins were placed hair to hair after the dye had been brushed
-on, and the color forced to the bottom of the hair by a workman tramping
-on the skins. The dyeing of seal was a typical illustration of these
-procedures. First the tips of the hair were dyed. The color was brushed
-on, allowed to dry, then the excess beaten out with rods. These operations
-were repeated until the proper depth of shade was obtained, often as many
-as a dozen or more applications of the dye being necessary. Then the base
-color was spread over the hair, and beaten or tramped in until the lower
-parts of the hair were penetrated. This process also required drying and
-beating out of the excess dye, as well as numerous applications of the
-dye to impart the desired color to the hair. Prior to the dyeing, the furs
-were killed, by brushing on a paste containing the essential ingredients,
-drying and beating and brushing the fur, just the same as in dyeing. It
-will be readily seen that such methods were exceedingly laborious, and in
-some cases the dyeing took many weeks, and even months.
-
-It was quite a step forward when a certain fur dyer, possessing a little
-more courage, or perhaps, experimenting spirit than the others, attempted
-to dye furs by dipping them entirely into a bath containing a solution
-of the dye instead of applying a paste as formerly. The advantages to be
-gained by such a method of dyeing were many. A large number of skins could
-be treated thus at one time, and this was a very important consideration
-in view of the great increase in the demand for dyed furs. By allowing the
-furs to remain in the dye solution until the proper shade was obtained,
-the time and labor of applying many coats of dye by brush was considerably
-reduced, and in addition, there was a greater probability of the products
-coming out all alike, uniformly dyed. The results as far as the hair
-was concerned, were indeed highly gratifying, but the condition of the
-leather after dyeing was not so encouraging. This difficulty has to a
-considerable degree been overcome, although there are frequent instances
-of the leather being affected by the dyeing process even with modern
-methods. However, the remedy in such cases, or rather the preventative
-is the proper dressing of the skins prior to the dyeing. The dip method
-of dyeing has acquired great importance, and is being employed in dyeing
-operations involving the handling of millions of skins annually. In
-certain instances, nevertheless, the brush method is of prime significance
-as in the dyeing of seal, and seal imitations on muskrat and coney,
-enormous quantities of furs being dyed in this fashion. In the majority
-of imitations dyed, both the brush and the dip methods must be used.
-
-Figure 19 illustrates the various types of brushes which are used at the
-present time for the application of the dye by the brush method. Each
-brush has a specific purpose and use. The procedure in brush dyeing is
-somewhat as follows. The skins, after being properly treated, that is,
-killed, and mordanted, are placed on a table, or work-bench, hair-side up.
-Then by means of a brush which is adapted to the nature and requirements
-of the particular fur, the solution is brushed on in the direction of
-the fall of the hair, occasionally beating gently with the brush so as to
-cause the dye to penetrate to the desired depth. Considerable skill and
-care must be exercised in this operation as it is rather easy to force
-the dye down further than is wanted, and in some cases the leather or the
-roots of the hair may be affected. The skin having received its coat of
-dye, is then dried and finished, if no other dyeing processes are to be
-applied. Frequently, with certain types of dyes, several applications of
-color are necessary, and these are brushed on as the first one, drying
-each time. Then, on the other hand, the skin may receive a dyeing in the
-bath by dipping, and for this also, the fur is first dried after the brush
-dyeing.
-
-[Illustration: FIG. 19. BRUSHES USED IN FUR DYEING BY THE BRUSH METHOD.]
-
-Quite recently, owing to the great quantities of furs which are being
-dyed as seal imitations, chiefly by the brush method, although the dip
-method is used in conjunction with it, machines have been invented to
-replace the hand brush, and the dye is now applied mechanically. Machines
-for this purpose are by no means new, there being records of inventions
-almost a score of years past, but they did not achieve much success.
-Brush-dyeing machines, to be efficient, must be designed to suit the
-needs of the particular type of fur to be dyed, otherwise there will be
-a great lack of uniformity in the dyed skins, a condition which cannot
-occur when the dye is brushed on by hand brushes. Figure 20A and B shows
-diagrammatically, machines invented within the past few years, which are
-used to dye mechanically furs by the brush process.
-
-[Illustration: FIG. 20. TYPES OF MACHINES FOR DYEING FURS BY THE BRUSH
-METHOD.
-
-_A._ (U. S. Patent 1,225,447.) _B._ (U. S. Patent 1,343,355.)]
-
-[Illustration: FIG. 21. DRUM FOR WORKING WITH LIQUIDS.
-
-(_Turner Tanning Machinery Co., Peabody, Mass._)]
-
-For the dipping process, the dye solution is prepared in vats, or
-liquid-tight drums, or in some instances in paddle arrangements. The
-skins are placed in the dye-bath, and the dyeing operation proceeds
-without any difficulty. After the proper shade is obtained, the furs
-are removed, washed free of excess dye, dried and finished. The dipping
-method is employed where a single shade is to be dyed on the fur, as the
-production of blacks on lambs. But in most cases, the dyeing in the bath
-is supplemented by the application of a coat of dye by the brush to the
-upper part of the hair, the color being usually a darker shade than the
-ground dyeing. Thus, for example, in the dyeing of imitation sable on
-kolinsky or a similar fur, the skins are first dyed the relatively light
-color of the under-hair by the dip process, then the dark stripe effect
-is brushed on.
-
-The blending of sables, martens, chinchillas or other rare furs, is not
-done in the same manner as with other furs, because each skin requires
-individual attention and a long and careful treatment. The dye solution
-is applied by means of very fine brushes or sometimes feathers, to the
-extreme tips of the hair, until the proper degree of color intensity is
-obtained. The time, labor, and skill necessary for this sort of work are
-warranted only in the case of the highest-priced furs, and the blendings
-are so excellent as to defy detection, except by experts.
-
-[Illustration: FIG. 22. DEVICE FOR CONVEYING SKINS.
-
-(_Turner Tanning Machinery Co., Peabody, Mass._)]
-
-After the furs have gone through all the operations required by the
-processes of killing, mordanting, dyeing and washing, they are ready to
-be dried and finished. The procedure is quite similar to that employed in
-fur dressing. Sometimes the leather side of the skins is brushed with a
-strong salt solution before drying, in order to replace some of the salt
-which was extracted during the dyeing processes. In other instances, a
-light coat of some oily substance is brushed on, to render the leather
-soft and flexible after drying, where there is a possibility of the skins
-turning out otherwise. Great care must be exercised in the handling of
-the dyed skins to avoid the formation of stains or spots on the hair,
-which might ruin the dyeing. As little handling of the furs as is feasible
-will reduce any trouble from this source. In conveying the wet skins
-from one part of the plant to another it is desirable to use a device
-such as is shown in Fig. 22. For drying, the same machines as described
-under Fur Dressing can be used, and similar care must be taken to avoid
-overheating or irregularity of drying. Drum-cleaning constitutes a very
-important operation in the finishing of the skins, the hair receiving
-a polish, and the full lustre and brilliancy of the dye being thereby
-brought out. Then after caging to remove the sawdust or sand, the skins
-are passed over the staking knife, or are treated in a machine suited
-for the purpose, to stretch them and to render them thoroughly soft and
-flexible. And therewith is concluded the work of the fur dyer proper, and
-the skins are ready to return to the furrier, in whose hands they undergo
-the metamorphosis into the fur garments to be worn chiefly by the feminine
-portion of humanity.
-
-
-
-
-CHAPTER X
-
-FUR DYEING
-
-"KILLING" THE FURS
-
-
-If dressed furs are treated with a paste or solution of a dye properly
-prepared, and at the right temperature, the hair will show very little
-tendency to absorb the coloring matter. Even after prolonged treatment
-with the dye, only a small amount will be taken up by the hair, and in a
-very irregular fashion. Soft, woolly hair, like that of lambs and goats
-will be colored more easily than that of furs with harder hair, and the
-under-hair of a fur will generally have a greater affinity for the dye
-than the harder and stiffer top-hair. Moreover, in some parts of the same
-fur, the hair will absorb more color than in other parts. In other words,
-the hair of furs resists the action of dye materials to a greater or less
-degree, depending upon the character of the fur, and also upon the part
-of the pelt. In order to overcome this resistance of the hair, and to
-render it uniformly receptive to the coloring substances, the furs are
-treated with certain chemical agents, the process being known technically
-as "killing."
-
-The origin of the term is obscure, but it is interesting to note that
-in the fur dyeing countries other than the United States and England,
-the corresponding expression is used: in Germany, "töten," and in France
-"tuer." The explanation of the process is as follows: The surface of the
-hair is covered with a fine coat of fatty material which renders the hair
-more or less impervious to dye solutions and solutions of other substances
-which may be used for dyeing purposes. This fatty coating of the hair
-cannot be removed by mechanical means, otherwise the hair would have
-been freed of it during the dressing operations. Chemical solvents must
-therefore be resorted to, and naturally alkaline materials are used, these
-being usually cheapest and also most effective in their dissolving action
-on fatty substances. Alcohol, ether, benzine, and other similar liquids
-also serve as killing agents on furs, since they too, are fat solvents.
-In all these cases, the fatty substance on the hair is dissolved away,
-and the protective coat which previously rendered the hair impervious
-to the dye, is now removed. There are certain chemicals however, which
-normally do not dissolve substances of a fatty nature, but are strongly
-oxidizing, such as peroxide of hydrogen, hypochlorites, permanganates,
-perborates, nitric acid, etc., and exert a killing action when they are
-applied to the hair, in that the hair is made capable of taking up the
-dye from its solutions. In this case the killing can hardly be said to
-be due to a degreasing process. The fact that killing can be brought
-about with other substances than alkalies or fat solvents, has led to
-the belief on the part of some investigators in this field that killing
-is more than a degreasing operation, although the removal of the fatty
-material of the hair undoubtedly takes place. Some authorities consider
-that the killing process changes the pigment of the hair, which thereby
-becomes more receptive to the dye. It is quite possible that some such
-change in the structure of the hair fibre does take place, the surface
-of the hair becoming slightly roughened, and therefore more capable of
-fixing the coloring matter. The question is still an open one, and since
-no conclusive researches have been made as yet, it will be assumed that
-killing is simply a degreasing process, inasmuch as the modern practise
-is based on this supposition, and very satisfactory results are obtained.
-
-An account of the historical development of the killing process brings
-out many interesting and enlightening facts, so it will be given here
-briefly. One of the first substances used for killing, or degreasing the
-hair of furs, was decomposing urine. Urine contains about 2% of urea which
-gradually changes to salts of ammonia, and in the presence of the air,
-largely to ammonium carbonate. This substance has a weak alkaline action,
-but sufficiently effective to be used for killing the hair of certain
-types of furs. Woolly furs, such as those derived from the various kinds
-of sheep and goats, were degreased with stale urine, the skins being
-washed in this, and then rinsed in water. The fat was emulsified by the
-ammonium carbonate present, and could thus be easily removed. For other
-furs, a stronger mixture was necessary. An example of a killing formula
-used on wolf, skunk and raccoon, which were to be dyed black, is the
-following:
-
-  350 grams beechwood ashes
-  200 grams unslaked lime
-  150 grams copper vitriol
-  100 grams litharge
-   60 grams salammoniac
-   40 grams crystallized verdigris
-  3.5 liters rain water
-
-Beechwood ashes were a very important constituent of the old killing
-formulas. The reason for that lies in the fact that beechwood contains
-a comparatively high percentage of potassium, which occurs in the ashes
-of the burned wood as potassium carbonate, or potash. The ashes alone
-were frequently used, being applied in the form of a paste, which in
-some instances had an advantage over a solution, in that the killing
-could be limited to certain parts of the skin where it was more desired
-than in other parts. By extracting the wood ashes with hot water, and
-evaporating the clear solution to dryness, potash could be obtained, which
-was considerably stronger than the original ashes. Next in importance
-for the killing was unslaked lime. This substance was also often used by
-itself, being first slaked with water, and using the milk of lime thus
-formed, after cooling. Salammoniac, although a salt, and consequently
-without any killing action, in contact with the beechwood ashes or the
-lime in solution or paste, liberated ammonia slowly, and so also acted
-as a degreasing agent. The other chemicals in the formula took no part
-in the actual killing of the hair, but acted either as mordant materials
-or as mineral dyes. The copper salts, in this mixture present in two
-forms, as sulphate in copper vitriol, and as acetate in the verdigris,
-were important constituents of the dye formula, being essential to the
-production of the proper shade. These substances properly had no place
-in the killing formula. The litharge, also was not a killing agent, but
-in the presence of the alkaline materials of the killing mixture, it
-gradually combined with the sulphur contained in the hair, forming lead
-sulphide, and thereby darkening the color of the hair. In this case,
-the metallic compound acted, not as a mordant, but as a mineral dye. The
-mixture was applied to the hair by means of a brush, the skins let lie for
-some time, then dried, brushed and beaten. Many applications were usually
-necessary to sufficiently degrease the hair. Inasmuch as the killing paste
-was prepared by mixing the constituents together, and then was brushed
-on at the comparatively low temperatures which the proper protection of
-the hair required, it is questionable whether some of the metal compounds
-were even enabled to act as described above as mordant or dye. In spite of
-the trouble and considerable time required in working with such a killing
-formula to obtain the hair in the desired condition for dyeing, the use
-of such a mixture nevertheless possessed the advantage that the hair was
-only very slowly and gradually acted upon, and so the gloss was preserved.
-The action of strong alkaline substances acting quickly is more or less
-detrimental to keeping the gloss of the hair, while the slow action of
-the weak alkaline paste of the old formulas, and the gradual formation
-of a protective metal film on the surface of the hair, rendered the hair
-suitably receptive to the dye which was subsequently applied, without in
-any measure affecting the lustre of the hair.
-
-It would be needless to describe or discuss any more of the old killing
-formulas, for the principle involved was the same in all cases, there
-being usually a slight variation in the content of metallic salts,
-beechwood ashes and unslaked lime being constituents of the great majority
-of the mixtures used. Modern killing processes employ substances quite
-similar to those of the old formulas, the operations, however, being much
-less laborious and less time-consuming, and the cheap, pure products
-which chemical science has been able to develop being used in place of
-the crude products crudely obtained from natural sources. The chemicals
-used at the present time for killing furs, are chiefly ammonia, soda ash,
-caustic soda, and caustic lime. The choice of the killing agent depends
-upon the nature of the fur, the hair of some furs being sufficiently
-killed by treatment with weak alkalies, while in other furs the hair may
-require stronger treatment. The ability of the hair of a particular fur to
-withstand the action of the different alkaline substances must be taken
-into consideration, there being a great divergence in this regard among
-the different classes of furs. Raccoon, for example, is not appreciably
-affected by a solution of caustic soda of 5 degrees Beaumé, while some
-wolf hair cannot withstand the action of a solution of soda ash of less
-than 1 degree Beaumé. Frequently much stronger alkalies are necessary to
-kill the top-hair than the under-hair, so this accomplished by treating
-the skins in a solution which is suited to kill the under-hair, and
-subsequently the top-hair is treated with a stronger solution, this being
-applied by the brush method.
-
-Uniformity of action of the killing material on all parts of the skin,
-and on all the skins of a given lot, is absolutely essential to obtaining
-satisfactory results in dyeing. And it is by no means a simple matter
-to get such uniformity, considering the numerous factors that must be
-taken into account. Any operation involving the immersion of the skins
-in solutions or even in water alone, has an effect on the leather side of
-the skin, inasmuch as some of the tanning materials may be extracted. The
-application of some substance of a fatty nature to a great degree prevents
-this, and the skin can be killed, mordanted and dyed, and then come out
-soft and flexible. But the great majority of substances of a fatty nature
-are affected by alkalies, and so when the skins are being killed, the
-action of the alkaline materials would be upon the fat contained in the
-leather as well as that upon the hair. As a result the hair may not be
-sufficiently killed, and so give uneven dyeings subsequently. Either a
-certain excess of the killing chemical must be used, and it would be very
-difficult to ascertain what quantity would suffice, or the killing action
-must be prolonged; but best of all, in oiling the skins, an inert mineral
-oil should be used, since it is wholly unaffected by alkalies.
-
-Skins may be killed by the brush process or the dip process, or by both.
-For brush killing, the stronger alkalies like lime and caustic soda are
-used, the solution being applied to the top-hair with a suitable brush,
-and the skins allowed to remain hair to hair for the necessary length
-of time, after which they are treated further as skins killed by the dip
-process. By this latter process, the furs are immersed in a solution of
-the desired killing agent in a vat, or drum, or other appropriate device
-which will permit of uniform action of the alkali on the hair of all the
-skins. After remaining in the solution the required length of time, the
-skins are drained, and rinsed in fresh water, and then entered into a weak
-solution of an acid in order to neutralize any remaining alkali, it being
-easier to wash out acid than alkali. The furs are then washed thoroughly
-in clear water, preferably running water, to remove the last traces of
-acid. The skins are then drained and hydro-extracted, or pressed, and are
-then ready for the subsequent operations of mordanting and dyeing.
-
-
-KILLING WITH SODA
-
-Soda is sodium carbonate, which is produced commercially in a very pure
-state in several different forms, the chief being sal soda, which is
-crystallized sodium carbonate, containing about 37% of actual soda; and
-soda ash, or calcined soda, which is anhydrous sodium carbonate. The
-latter is the variety most commonly used.
-
-  10 grams soda ash are dissolved in
-   1 liter of water at 25°-30° C.
-
-The skins are immersed for 2-3 hours, after which they are rinsed and
-treated with
-
-  10 grams acetic acid dissolved in
-   1 liter of water.
-
-The skins are again thoroughly washed, and then hydro-extracted.
-
-
-KILLING WITH LIME
-
-Lime, calcium oxide, forms a white, amorphous, porous substance, which
-readily takes up water, giving calcium hydroxide, or slaked lime. Only the
-best grades of lime should be used, as it is very frequently contaminated
-with calcium carbonate and other inert materials.
-
-  10 grams of lime are dissolved in
-   1 liter of water.
-
-The skins are entered, and allowed to remain for a period of time which
-varies according to the nature of the fur. During the killing, the
-solution must be agitated, in order to evenly distribute the milk of lime,
-which has a tendency to settle out. After rinsing, the skins are "soured,"
-by treating with weak acetic acid solution, then thoroughly washed, and
-drained.
-
-
-KILLING WITH CAUSTIC SODA
-
-Caustic soda is used only on furs the hair of which is very hard and
-resistant to killing. Usually it is applied by the brush process, but in
-some instances, the dip method must be used. In order to reduce as far
-as possible, the action of the caustic soda on the leather, the weakest
-permissible solutions are used, increasing the time of treatment, if
-necessary. Caustic soda is a white, crystalline substance, occurring
-in commerce in lumps, but more conveniently in a solution of 40 degrees
-Beaumé, containing 35% of caustic soda. Various quantities, ranging from
-4 to 25 grams of this solution per liter of water are taken, according to
-the character of the fur, and the skins treated for 2-3 hours, although
-weaker solutions may be used, and increasing the duration of the killing.
-By keeping the solution in motion, by means of a stirrer or any other
-method of agitation, the best results are obtained. After the skins are
-sufficiently killed, they are soured, and washed as by the other killing
-methods.
-
-Where the nature of the hair of the fur is such that the top-hair and
-the under-hair require different killing treatments, the skins are first
-killed by the dip process, with an alkali suited to kill the under-hair,
-then a brush killing with a stronger alkali is applied to the top-hair.
-The subsequent treatments are the same as for usual dip-killing methods.
-
-
-
-
-CHAPTER XI
-
-FUR DYEING
-
-MORDANTS
-
-
-The hair of furs has the peculiar quality of fixing the oxides or
-hydroxides of certain metals from dilute solutions of their salts.
-Advantage is taken of this property to mordant the furs, that is, to cause
-a certain amount of the metallic oxide or hydroxide to be permanently
-absorbed by the fibres. The term mordant comes from the French word
-"mordre," meaning to bite, it being formerly considered that the purpose
-of a mordant was to attack the surface of the hair in such a way as to
-permit the dye to be more easily absorbed. In fact, killing mixtures,
-which were intended for this same object, used to contain the various
-chemicals which have a mordanting action, in addition to the alkaline
-constituents. The mordants were not applied as such, but always as
-killing materials. It was later realized, however, that the mordant was
-instrumental in the production of the color itself.
-
-Mordanting may be considered as having a two-fold object: first, to help
-fix the dye on the fibre in a more permanent fashion, thus rendering the
-dyeings faster; and secondly, to help obtain certain shades of color, as
-the various mordants produce different shades with any given dye. Some
-classes of dyes can be applied to furs without the use of mordants, but
-other types are taken up only in a very loose manner, being easily washed
-out from the hair with water, and it is only when such dyes are brought on
-to the hair in the form of a metallic compound, producing what is known as
-a "lake," that really fast dyeings are obtained with them. The substances
-which are used for mordanting the hair are certain metallic compounds,
-but not all metallic salts which are used in dyeing are mordants.
-Sometimes such a compound is employed to develop the color of the dyeing
-by after-treatment, as in the case of after-chroming, the action of the
-metallic salt being directed only to the dye, and is not fixed by the
-fibre as a mordant must be. In order for a metallic compound to act as a
-true mordant, it must be fixed by the hair, and it must combine with the
-dye, thus forming a sort of connecting link between the dye and the hair.
-It is not absolutely essential that the mordant be applied first, although
-this is the customary and commonest practise. There are three ways by
-which the mordants can be fixed on the fur hair: First, by the absorption
-of the metallic oxide or hydroxide from a solution of the mordant prior to
-the dyeing; second, the mordant may be fixed on the fibre at the same time
-as the dye; and third, the mordant may be applied after the fur has been
-treated with the dye. The last two methods will be discussed in connection
-with the dyes, as they are special cases.
-
-The salts of metals which are comparatively easily dissociated in water,
-with the formation of insoluble oxides or hydroxides, are most applicable
-as mordants for furs, and among them are compounds of aluminum, iron,
-chromium, copper and tin. The constituents of the hair seem to bring
-about the dissociation of the metallic salt, and the oxide or hydroxide
-as the case may be, is absorbed and firmly fixed by the hair. Just what
-the manner and nature of this fixation are, is still uncertain. It is
-supposed that chemical combination takes place between the hair and the
-metal. The course of this process may, as far as is known, be described
-as follows, taking, for example, the case of chromium sulphate: In dilute
-solution, this compound gradually dissociates first into its basic salts,
-and finally into the hydroxide, the breaking up of the neutral salt being
-induced by the presence of the fur-hair.
-
-  Cr{2}(SO{4}){3} + 2H{2}O = Cr{2}(SO{4}){2}(OH){2} + H{2}SO{4}
-     chromium        water         first basic        sulphuric
-     sulphate                      chrome salt          acid
-
-  Cr{2}(SO{4}){2}(OH){2} + 2H{2}O = Cr{2}(SO{4})(OH){4} + H{2}SO{4}
-                                       second basic
-                                        chrome salt
-
-  Cr{2}(SO{4})(OH){4} + 2H{2}O = Cr{2}(OH){6} + H{2}SO{4}
-                                   chromium
-                                   hydroxide
-
-These reactions take place within the fibre, after the hair has been
-impregnated with the solution of the neutral salt, and when the compound
-has been rendered completely basic, in other words has reached the form of
-the hydroxide, it is supposed to combine with the acid groups contained
-in the hair substance, forming thus some complex, insoluble organic
-compound of the metal within the hair. According to some authorities the
-mordant is supposed to be present in the hair simply as the hydroxide,
-being tenaciously held by some physical means. The facts seem to indicate,
-however, that the metal is actually combined in some chemical way with the
-hair. For, if the mordant were present as hydroxide, then on white hair it
-would show the color of the hydroxide, which it does not. The same facts
-obtain with regard to other metals.
-
-In order for the hair to be properly mordanted, it is necessary that
-the metallic compound which is taken up by the hair be held in such a
-manner that the mordant cannot be removed by water or even dilute acids
-or alkalies. Salts which dissociate too readily produce mordants which
-are only superficially precipitated on the hair and subsequently come
-off. Usually some substance is added to the solution of the salt to
-cause slower and more even dissociation of the salt, so that the hair
-substance can be quite saturated with the metallic compound before any
-insoluble precipitate is formed. Dilute sulphuric acid, organic acids like
-acetic and lactic, and cream of tartar are used to facilitate the uniform
-absorption of the mordant salt by the hair.
-
-When the skins are mordanted before dyeing, they are immersed for 6 to
-24 hours in a solution containing 1 to 20 grams of the metallic salts per
-liter of water, together with the corresponding quantity of the assistant
-chemical. The skins should be so entered into the mordant solution that
-the hair is uniformly in contact with the solution, and all the skins
-so that they are acted upon alike. Machinery such as is used for killing
-is suitable for mordanting also. The duration of the mordanting, and the
-concentration of the solutions are varied according to the depth of shade
-required, and also according to the nature of the dye to be employed. By
-suitably combining several mordants a considerable range of colors can be
-obtained with a single dye.
-
-The various chemicals used as mordants are essentially the same no matter
-for which class of dyes they are used, there being only slight differences
-in the concentrations of the solutions, the manner of application of
-the mordants being practically the same. It is interesting to note that
-with the exception of chromium compounds, which are of comparatively
-recent adoption as mordants, all the chemicals now used for mordants
-were employed by the earliest masters of the art of fur dyeing. While
-some of the formulas used by those dyers display a lack of appreciation
-of the true action and function of the mordanting chemicals, yet it is
-quite remarkable that they chose, in spite of their limited knowledge of
-chemical processes and phenomena, just those materials which do act as
-mordants if properly applied. The most important metallic compounds for
-mordanting furs at the present time are salts of aluminum, iron (ferrous),
-copper, tin and chromium (as well as chromates and bichromates). The
-compounds of the metals with organic acids such as acetic acid are
-preferable, being more easily dissociated, and also leaving in solution
-an acid which is less injurious to the fur than a mineral acid. However,
-sulphates and other salts of the metals are also used extensively,
-inasmuch as they are cheaper than the organic salts.
-
-
-ALUMINUM MORDANTS
-
-Chief among the aluminum mordants are the various kinds of alum, which is
-a double sulphate of aluminum and an alkali such as sodium, potassium or
-ammonium. All these salts except that of sodium, form large, colorless,
-octahedral crystals, and are soluble in about 10 parts of cold water,
-and 1/4 part of hot water. Sodium alum is even more easily soluble, but
-on account of the difficulty of obtaining it in crystalline form, it
-is little used. The common commercial alum is the potassium aluminum
-sulphate.
-
-Recently, aluminum sulphate has to a large extent replaced alum for
-mordanting purposes, because it can be obtained very cheaply in pure form,
-and it contains a greater amount of active aluminum compound than does
-alum. Only the iron-free salt, however, may be used for the needs of fur
-dyeing.
-
-Aluminum acetate also finds extensive application as a mordant in fur
-dyeing, and while somewhat more expensive than the alum or aluminum
-sulphate, it has the advantage over these compounds of being combined
-with an organic acid, which is preferable when the action on the hair and
-leather is considered. Aluminum acetate can be obtained in the market in
-the form of a solution of 10 degrees Beaumé, but can also be prepared very
-easily as follows:
-
-   665 grams pure aluminum sulphate, or
-   948 grams potassium alum, are dissolved in
-     1 liter of hot water.
-  1137 grams of lead acetate (sugar of lead) are also dissolved in
-     1 liter of hot water.
-
-The two solutions are mixed, and thoroughly stirred. A heavy white
-precipitate forms, which is filtered off, and discarded after the solution
-has cooled. The aluminum acetate is contained in the filtrate, and the
-solution is brought to a density of 10 degrees Beaumé by the addition of
-water, if necessary, and is preserved for use in this form.
-
-
-IRON MORDANTS
-
-Ferrous sulphate, iron vitriol, or copperas, as it is commonly known,
-forms pale green crystals, which on exposure to air lose water, and
-crumble down to a white powder. It is very soluble in both cold and
-hot water, but the solutions oxidize very rapidly, turning yellowish,
-and should therefore be used immediately. Care must be taken that a
-good quality of iron vitriol be used for the mordant, otherwise very
-unsatisfactory results will be obtained.
-
-Ferrous acetate is prepared in a manner similar to the aluminum acetate,
-and is occasionally employed instead of the ferrous sulphate. Inasmuch,
-however, as the solution of ferrous acetate is very easily oxidizable
-when exposed to the air, a more stable form is used, and this comes on
-the market as iron pyrolignite or iron liquor. This can be prepared by
-dissolving iron in crude acetic or pyroligneous acid, or by treating a
-solution of iron sulphate with calcium pyrolignite. Iron liquor is really
-a solution of ferrous acetate that contains certain organic impurities
-which prevent, or rather, considerably retard the oxidation of the iron
-salt, but which in no way interfere with its mordanting properties. The
-commercial product can be had in various concentrations, but 10 degrees
-Beaumé is the most usual and most convenient.
-
-
-COPPER MORDANTS
-
-The most important copper salts used in fur dyeing processes are copper
-sulphate, or blue vitriol, occurring in large blue crystals, very soluble
-in cold and in hot water; and copper acetate, which is formed by treating
-a solution of copper sulphate with a solution of the requisite quantity
-of lead acetate. Copper acetate can also be obtained in the form of
-blue-green crystals, very soluble in water, the solution becoming turbid
-on prolonged heating, due to the formation of a greenish basic copper
-acetate. This insoluble compound is known commonly as verdigris, although
-it is not usually produced in the manner mentioned. Numerous fur dyeing
-formulas contain verdigris, but inasmuch as the basic copper acetate is
-insoluble and thus incapable of reacting with any of the substances used
-in dyeing, it is assumed that the soluble normal copper acetate was meant,
-for this compound is also sometimes called verdigris.
-
-In addition, there must be mentioned here a compound which formerly found
-extensive use in fur dyeing. This is a double salt of copper and iron,
-analogous to alum, ferrous copper sulphate, known as blue salt. It is very
-seldom used at the present time, being more effectively replaced by other
-substances.
-
-
-CHROMIUM MORDANTS
-
-The typical chromium mordant is chrome alum, which is a potassium or
-ammonium chromium sulphate, constituted just like the aluminum alums, and
-forming crystals like these. More frequently used, nevertheless, than the
-chrome alum, is chromium acetate, which is prepared from it, either by
-treating a solution of the chrome alum with a solution of lead acetate,
-or in the following manner:
-
-   50 grams of chrome alum are dissolved in
-  500 cubic centimeters of boiling water. To this is added
-   15 grams of 20% ammonia, diluted with 15 grams of water.
-
-The precipitate which forms is filtered off, and preserved, the filtrate
-being discarded. After thoroughly washing the residue on the filter it is
-dissolved in dilute acetic acid, heating if necessary, to effect solution.
-
-Other chromium compounds of an entirely different type are also used in
-fur dyeing, these being chromates and bichromates, the latter finding
-greater application than the former. Sodium bichromate is the salt most
-usually employed. This forms orange-red crystals which are very soluble
-in water, and in addition to its use as a mordant it also serves as an
-oxidizing agent for developing or fixing certain dyes on furs.
-
-
-TIN MORDANTS
-
-Compounds of tin find only limited application in fur-dyeing, the only one
-of importance being tin salts, stannous chloride, which occurs in the form
-of white, hygroscopic crystals, which must be preserved in closed vessels.
-It is very soluble, but in dilute solutions it readily forms a basic salt,
-so stannous chloride is usually used in very concentrated solutions.
-
-
-ALKALINE MORDANTS
-
-After the furs have been treated with the solution of some alkali for the
-purpose of killing the hair, they are always passed through a slightly
-acidulated bath to remove any alkali which may still be adhering. This
-operation must always be gone through before the skins can be mordanted
-or dyed, for if it were neglected, very uneven and uncertain results
-would be obtained. This process, however, entails the expenditure of
-no small amount of time, labor and chemicals when large lots of skins
-are being handled. In order to eliminate this extra step of "souring"
-between killing and mordanting or dyeing, it has been proposed to use
-alkaline mordants which combine the killing and mordanting functions,
-and accomplish these two processes at the same time. The advantages of
-employing such mordants are easily apparent. Cumbersome manipulation and
-handling of the skins, with the attendant consumption of much time and
-labor are reduced to a minimum, and besides there is no needless waste of
-chemicals as is the case in the ordinary methods of killing the furs.
-
-The principle of alkaline mordants is not a strictly new one. If it
-be remembered that the old killing formulas used by the fur dyers of
-an earlier age, contained metallic salts with mordanting properties in
-addition to the alkaline substances, which alone were effective as killing
-agents, it would seem that the suggested alkaline mordants were merely a
-revival in modified form of the old processes. This is undoubtedly true
-in a large measure, for the killing mixtures which the old masters used
-certainly embodied the fundamental principle of simultaneous killing and
-mordanting, although it was not recognized at that time.
-
-Modern alkaline mordants have therefore been devised which can be employed
-for killing and mordanting furs at the same time. They are prepared as
-follows:
-
-
-ALKALINE ALUMINUM MORDANT
-
-  250 grams of potassium alum are dissolved in
-    1 liter of boiling water. To this solution is added
-  300 grams of soda ash, previously dissolved in
-  750 c.c. of water, and the resulting precipitate is filtered off,
-      washed and pressed, and then dissolved in a solution of 65 grams
-      of caustic soda in 1 liter of water.
-
-
-ALKALINE CHROMIUM MORDANT
-
-  250 c.c. of chrome acetate mordant of 20 degrees Beaumé
-  320 c.c. of caustic soda solution of 38 degrees Beaumé (32.5%)
-   10 c.c. of glycerine 30 degrees Beaumé (95%)
-
-The solution of these substances is brought up to a volume of 1 liter by
-the addition of 420 c.c. of water.
-
-
-ALKALINE IRON MORDANT
-
-   138 grams ferrous sulphate are dissolved in
-   362 c.c. of warm water. Cool and add
-    25 c.c. of glycerine. Then slowly and carefully add
-  25.5 c.c. of concentrated ammonia, taking care that no precipitate
-       forms.
-
-While these alkaline mordants seem to have much in their favor, there
-are certain possible objectionable features which must be considered.
-The solutions of the mordants are generally very alkaline, and not every
-fur can withstand more than a limited quantity of alkaline substance
-for longer than a comparatively short time. Suitable mordanting usually
-requires a longer time than killing does, so with the use of the alkaline
-mordant, if the skins remain in the solution until sufficiently killed,
-they may be insufficiently mordanted, while if the furs are treated long
-enough to be properly mordanted, the hair may have been over-killed.
-However, the idea of the alkaline mordant is a good one, and it is
-only a matter of time and patient, scientific experimentation when the
-difficulties of the method will be eliminated, and a much-desired process
-will become a practical realization.
-
-The general methods for applying the various mordants of all sorts follow
-closely the procedure adopted for the killing formulas, and similar
-precautions must be observed, in order to obtain consistently uniform
-results. With the exercise of care, there is little reason for the
-mordanting operations to go wrong.
-
-After proper treatment of the skins in the mordants, they are removed and
-drained off, then rinsed lightly in running water to remove the excess
-of mordant liquor, after which they can be directly entered into the
-dye bath. If it is not feasible to dye the mordanted skins at once, as
-is often the case, the skins are kept moist, and under no circumstances
-allowed to dry.
-
-
-
-
-CHAPTER XII
-
-FUR DYEING
-
-MINERAL COLORS USED ON FURS
-
-
-Before the introduction of the fur dyes now used, certain inorganic
-chemical substances were employed in addition to the vegetable dyes,
-for the production of colors on furs. Even to this day such materials
-are used to obtain certain effects in special instances. The idea of
-employing mineral chemicals undoubtedly originated in the textile-dyeing
-industry, which at one time was dependent to an appreciable extent on
-mineral substances for the production of certain fast shades. Compounds
-of iron, lead, manganese, also of copper, cobalt and nickel were all used
-for dyeing, either singly or in various combinations. In the application
-on furs, the brush method was the only one practicable, as the skins would
-have been ruined by dipping them into solutions of these chemicals in the
-concentrations necessary for dyeing.
-
-The dyeing of furs with mineral colors involves the precipitation on
-the fibre in a more or less permanent form of the sulphide, oxide or
-other insoluble compound of a metal, and can be brought about in several
-ways. By what is known as double decomposition, that is, by the use
-of two solutions successively applied, the ingredient of one causing a
-precipitate to form when in contact with the constituent of the second,
-the color is produced on the hair. Another method is to use solutions of
-chemicals which decompose on contact with the hair, forming an insoluble
-compound. In the first method the hair is alternately treated with the
-two solutions of the requisite chemicals, drying between each brushing,
-the process being repeated until the desired shade is obtained. The second
-method merely requires the solution of the chemical to be applied to the
-hair, which is then dried, the color forming by itself.
-
-One of the most important of the mineral dyes, and which is occasionally
-used to this day, is lead sulphide, formed by the double decomposition
-method by precipitating a soluble lead salt with ammonium sulphide, or any
-other alkaline sulphide. By simply brushing an aqueous solution of lead
-acetate, also known as sugar of lead, on a white fur such as white hare or
-rabbit, a light, brownish coloration is obtained due to the combination of
-the lead with the sulphur of the hair. If the lead solution is carefully
-applied several times on this type of fur, until a sufficiently dark
-color is produced, it is possible to get a fairly good imitation of the
-stone marten. The brown color is very fast, being actually formed within
-the hair. In most cases, however, for dyeing lead sulphide shades it is
-necessary to use the two solutions. Thus the pale greyish or slightly
-brownish-grey shades of the lynx can be reproduced on white rabbit or
-hare by this process. A solution containing 60 grams of lead acetate per
-liter of water is brushed on to the hair of the fur which has previously
-been killed in the usual manner, and the hair is then dried. A solution
-of 50 grams of ammonium sulphide per liter of water is next brushed on,
-and the fur again dried. Care must be exercised in handling the ammonium
-sulphide as it is a very malodorous liquid, the fumes of which are
-poisonous when inhaled. The alternate brushings are repeated until the
-desired depth of shade is obtained. A very dark brown, approaching a black
-can be obtained in this way. This color can be used for the production of
-certain attractive effects. By brushing over the tips of the hair, which
-has previously been dyed a dark brown by means of the lead sulphide color,
-with a dilute solution of hydrochloric acid, or with peroxide of hydrogen,
-the hair will become white in the parts so treated, due to the formation
-of lead chloride or lead sulphate, respectively. Thus white tipped furs
-can be obtained, but the process is applicable only when the furs have
-been dyed by the lead sulphide method.
-
-Potassium permanganate is occasionally used to produce dyeings of a
-brown shade on furs. Considerable care has to be taken in applying this
-substance, as it is possible to affect the hair. The strength of the
-solution must be varied according as the hair to be dyed is weak or
-strong. A cold solution of 10 to 20 grams of potassium permanganate per
-liter of water is brushed on to the hair, which is then dried. A brown
-precipitate of manganese is formed on the hair after a short time, and
-the process is repeated until the required shade is obtained. For furs
-with harder hair, stronger solutions can be used. The dyeing is very
-fast, but it is seldom used, cheaper and better shades being obtained in
-other ways. Spotted white effects can be produced on the brown dyeing with
-permanganate of potash by applying a solution of sodium bisulphite, the
-brown color being dissolved by this chemical.
-
-The compounds of other metals, such as iron, copper, cobalt and nickel
-are not used in practise as the dyeings are not fast, and can be better
-produced in other ways.
-
-
-
-
-CHAPTER XIII
-
-FUR DYEING
-
-VEGETABLE DYES
-
-
-With the exception of the few shades which could be produced solely by
-means of coloring matters of a chemical character, all dyeings on furs up
-to about thirty years ago were made with dye substances obtained from the
-vegetable kingdom, either alone, or in conjunction with the aforementioned
-mineral colors. The colors of vegetable origin used in comparatively
-recent times were mainly extracts of the wood of certain trees; so the
-name "wood dyes" has come to be applied generally to the dyes of this
-class. The use of the vegetable or natural dyes on furs dates back to
-quite ancient times, as frequent allusions and descriptions in Biblical
-and other contemporaneous literature testify. There are numerous pictures
-on monuments and tablets illustrating the dyeing of furs among the ancient
-Egyptians, the evidence indicating that the juice of certain berries, and
-extracts of certain leaves were used for the purpose. At a later period,
-in the Roman era, henna, which was used over two thousand years ago as
-to-day for the beautification of the hair of women, was also used to
-color fur skins. The instances cited here are merely of scientific and
-historical interest, and are not of practical importance as far as fur
-dyeing methods are concerned.
-
-It was not until many centuries later that the dyeing of furs took on
-the aspects of a commercial art, and the substances then employed were
-chiefly tannin-containing materials such as gall-nuts and sumach, which
-in conjunction with certain metallic salts, particularly those of iron,
-were capable of producing dark shades. The use of iron compounds to form
-dark grey or black colors on leather tanned by means of the tannins, had
-been common for a long time, and it was natural that fur dyers should
-try to produce such shades on furs in a similar fashion. The use of the
-iron-tannin compound as a dye proved to be very effective, and to this day
-the production of blacks by means of the vegetable coloring matters has as
-a basis an iron-tannate. A formula in common use in the latter seventeenth
-and the eighteenth centuries for producing black shades on furs, is the
-following:
-
-  Lime water                1117 parts
-  Gall-nuts                 1500   "
-  Litharge                   500   "
-  Salammoniac                 65   "
-  Alum                       128   "
-  Verdigris                   64   "
-  Antimony                    64   "
-  Minium                      32   "
-  Iron filings               128   "
-  Green copperas             384   "
-
-All these substances except the gall-nuts, the copperas and half the lime
-water were boiled up in a cauldron; then the gall-nuts and the copperas
-were placed in a bucket and the contents of the cauldron poured in, and
-the rest of the lime water added. The mixture was stirred up, allowed to
-settle for an hour, and when cool, was ready to be applied by the brush
-method. For dyeing by the dip process, a similar mixture was used, only
-considerably diluted with water. A study of the formula discloses the
-fact that in it are combined killing and mordanting substances as well
-as dyeing materials. The lime water, in conjunction with the salammoniac
-serves as a killing agent, the verdigris, copperas and alum are mordants,
-while the litharge and the minium, both compounds of lead, could possibly
-act as mineral dyes, and the iron filings and the antimony took virtually
-no part at all in the dyeing, except, perhaps to act in a mechanical way.
-
-The formulas for other shades were made up along similar lines, the chief
-constituent of vegetable nature being either gall-nuts, sumach, or both.
-A mixture for a chestnut brown, for example, contained gall-nuts, sumach,
-and the various other mineral constituents as in the black dye, litharge,
-alum, copperas, verdigris, salammoniac, antimony, and in addition, red
-lead and white lead. It is evident in both these instances that the shade
-obtained was as much the result of mineral dyeing as of vegetable dyeing.
-
-The discovery of America introduced into Europe many new dye substances,
-chiefly wood extracts such as logwood and Brazilwood, but it was not until
-the nineteenth century that these materials found their way into the
-dye formulas of the fur dyer. Most of the processes used in the dyeing
-of furs were adaptations of methods employed in silk dyeing, the silk
-fibre being considered as most nearly approaching fur-hair in nature and
-characteristics. By devious and circuitous paths the formulas of the silk
-dyers reached the fur people, and so, in the middle of the nineteenth
-century, dye mixtures containing the various dyewoods as well as the
-tannin-containing substances were in general use for the dyeing of furs.
-The following is a typical recipe of that time for the production of black
-on furs like wolf, skunk, raccoon, etc.:
-
-  Roasted gall-nuts         1000 parts
-  Sumach                     200   "
-  Iron mordant               200   "
-  Copper vitriol             100   "
-  Litharge                    80   "
-  Alum                        60   "
-  Salammoniac                 50   "
-  Crystallized verdigris      40   "
-  French logwood extract      30   "
-  Rain water                7000   "
-
-The mixture was boiled up, and after cooling was ready for application by
-the brush method, the skins being first killed by a killing mixture also
-applied by the brush. The dye substances in this case are the gall-nuts,
-sumach and the logwood extract, with the iron mordant, copper vitriol, and
-alum as mordants. For brown shades a similar formula was used containing
-Pernambuco wood extract, logwood extract, quercitron bark, gall-nuts and
-dragonblood, together with iron, copper and alum mordants.
-
-Formulas such as the above were mainly empirical, that is, they
-were compounded as a result of trial of various combinations of the
-constituents, without considering the nature and quantitative character
-of the reactions, as long as the desired shades could be obtained. Such
-dye mixtures were frequently found to yield results varying from those
-expected or originally obtained, because the effectiveness of the formulas
-depended upon the exact duplication in every detail, of conditions which
-had given satisfactory results previously, and it was not always possible
-to attain such an accurate reproduction of circumstances, especially
-when the fur dyers were quite ignorant of the scientific relationships
-of the materials used. So when more light had been shed on the nature
-and chemical characteristics of the vegetable dye substances, formulas
-like those described were no longer employed, although the essential
-ingredients were the same in the new processes. Unnecessary constituents
-were eliminated, and proper ones substituted where it was required, and
-the quantities of the materials used were made to conform to the chemical
-laws governing the reactions. Since these new formulas were based on a
-rational understanding of the constituents and their reactions, it is
-desirable to study the latter briefly, before further discussing the
-formulas themselves.
-
-The substances of vegetable origin used in modern fur dyeing may be
-grouped into two classes, one, the tannin-containing materials, and
-the other, the dyewoods proper. The most important of the tannins are
-gall-nuts, sumach and chestnut extract. Cutch, which also comes under
-this class, is more frequently used for the production of brown shades,
-so it is grouped with the dyewoods. Among the latter are logwood, fustic,
-Brazilwood, quercitron, turmeric, and several others of less significance.
-
-
-1. _Tannin Materials_
-
-First and foremost under this heading are the nutgalls. These are
-ball-shaped excrescences produced on certain plants by the punctures
-of insects in depositing their eggs. There are two chief varieties, the
-European, and the Chinese. The European galls are formed by the female
-gall-wasp which drops an egg in the rind of young branches of certain
-oaks. A swelling (the nutgall) is produced, in which the young insect
-develops, and from which it finally escapes by piercing a hole through
-the shell. Those galls which are not pierced have a fresh bluish or green
-color, are heavy and contain most tannic acid. After the insect has gone
-out, the galls are of a lighter, yellowish color, and also of inferior
-quality. The best oak-galls are the Aleppo, and the Turkish or Levant
-galls, containing 55-60% of tannic acid, and about 4% of gallic acid. The
-Chinese galls are produced by the puncture of a plant-louse on the leaves
-and leaf-stalks of a species of sumach, and not on oaks. The galls are
-very light, and very rich in tannic acid, containing often as much as 80%.
-For dyeing purposes, nutgalls are usually ground to a powder, and in some
-instances they are even roasted first and then ground.
-
-Sumach consists of the leaves and sometimes of the small twigs and stems
-of a species of sumach plant known as the Rhus coriaria. The Sicilian
-variety is the finest commercial quality, with the Virginian ranking next.
-It is sold as a powder, but also in the form of the whole or crushed
-leaves. The best sumach contains 15-25% of tannin. Extracts are also
-manufactured, a liquid extract of 52 degrees Twaddell, which forms a dark
-brown, thick paste; and a solid extract, formed by evaporating the liquid
-extract to dryness.
-
-Chestnut extract is prepared from the wood of the chestnut oak, which
-contains 8-10% of tannin. The solid extract has a bright, black color,
-while the liquid extract is a dark brown paste with a smell like that of
-burnt sugar.
-
-The tannins all give greyish to black shades with iron salts, and it is
-this fact which renders them important for fur dyeing.
-
-
-2. _Wood dyes_
-
-One of the most important of all the natural dye substances, especially
-for the production of blacks, is logwood. The color is really a red, but
-with the common mordants it forms blue, violet or black shades. Logwood,
-or campeachy wood, as it is sometimes called, is the product of a large
-tree growing in the West Indies, and Central and South America. When
-freshly cut, the wood is practically without color, but when exposed to
-the air it soon becomes a dark reddish-brown on the surface. The coloring
-principle of logwood is called hematoxylin, which is a colorless substance
-when pure, and is of itself incapable of dyeing; but when it is exposed
-to the air, especially when moist and in the presence of some alkaline
-substance, it is converted into hematein, which is the real coloring
-matter of logwood. To prepare the wood for use, the logs are chipped or
-rasped, the chips being heaped up and moistened with water. Fermentation
-occurs, and the heaps are frequently turned to allow free access of air to
-the wood, and to prevent overheating. As a result of this process, a great
-part of the hematoxylin is converted to the hematein. The logwood may
-be used for dyeing in this state as chips, but logwood extracts can now
-be obtained of a high degree of purity and are easier to work with. The
-commercial forms of the extract, are the liquid of 51 degrees Twaddell,
-and the solid extract. Hematein crystals can also be obtained. All these
-extracts contain mainly hematein, together with a small percentage of
-hematoxylin which is converted to the former during the dyeing process.
-Logwood is never used as a direct dye, but is used to form color lakes
-with the various mordants, the following colors being produced:
-
-  Iron mordants give grey to black shades
-  Copper mordants give green-blue to black shades
-  Chrome mordants give blue to black shades
-  Aluminum mordants give violet shades
-  Tin mordants give purple shades
-
-By combining several of the mordants, any desired shade of black can be
-obtained, and if other dyewoods are used in conjunction with the logwood,
-the range can be further increased.
-
-Fustic, yellow-wood, or Cuba wood, as it is variously called, is obtained
-from a tree also growing in the West Indies, Central and South America.
-It is used either as wood chips, or as a paste extract of 51 degrees
-Twaddell, and occasionally as solid extract. Fustic contains two coloring
-matters, morintannic acid, possessing the characteristics of a tannin, and
-which is quite soluble in water, and morin, which is rather insoluble, and
-which settles out from the liquid extract. Fustic is the most important of
-the yellow dyes of natural origin, and is used considerably in fur dyeing
-with logwood for shading the blacks, or for producing compound shades.
-With the usual mordants fustic gives the following colors:
-
-  With iron salts           dark olive
-  With copper salts         olive
-  With chrome salts         olive-yellow to brownish-yellow
-  With aluminum salts       yellow
-  With tin salts            bright yellow to orange-yellow
-
-Brazilwood, or redwood, is the product of a tree found in Brazil, and
-exists in several varieties, such as peach wood, Sapan wood, Lima wood,
-and Pernambuco wood. They all yield similar shades with the various
-mordants, and all seem to contain the same coloring principle, brasilin,
-which, like the hematoxylin, has no dyeing power, but by fermentation and
-oxidation it is converted to brasilein, corresponding to the formation
-of hematein. Brazilwood and the related woods are used either as chips or
-extract, but seldom alone, usually in conjunction with other dyewoods. By
-combining logwood, fustic and Brazilwood in various proportions, and by
-employing suitable mordants, all the shades required by the fur dyer can
-easily be produced.
-
-Quercitron is the inner bark of a species of oak (Quercus tinctoria) found
-in the United States. It contains two coloring principles, quercetrin and
-quercetin. The fresh decoction of quercitron bark is a transparent dull
-orange-red which soon becomes turbid and deposits a yellow crystalline
-mass. It is generally used in conjunction with other dyes.
-
-Cutch is the dried extract obtained from a species of acacia, the
-principal varieties being Bombay, Bengal, and Gambier cutch. It contains
-two coloring principles, catechin and catechu-tannic acid. Cutch acts as
-a tannin, and like other tannins discussed above, can be used for the
-production of grey or black shades with iron mordants. It is employed
-chiefly, however, for dyeing browns. Aluminum salts give with cutch
-a yellowish-brown, tin salts give a lighter yellow, copperas gives a
-brownish-grey, and chrome and copper salts give brown shades.
-
-Turmeric is the underground stem of the Curcuma tinctoria, the coloring
-principle being called curcumin. It may be used as a direct dye, but
-usually a mordant is used. Turmeric is sometimes used in place of fustic.
-
-While the tannins can be used alone with an iron mordant for producing
-greyish to black shades, the dyewoods alone yield colors which would be
-too bright to be suitable for dyeing furs. In order to tone down this
-brightness, and to give to the dyeings that greyish undertone which is
-characteristic of the natural furs, and which can only be imitated by
-means of the iron-tannin compound, it is customary to combine the tannins
-with the wood dyes. The iron-tannate constitutes the foundation of the
-color which gets its intensity, and necessary brilliancy and bloom from
-the wood dyes. Moreover, the presence of the iron-tannin compound helps
-considerably to increase the fastness of the dyeing. Furs dyed with the
-combination of the tannins and the wood dyes obtain an additional tanning
-treatment which materially improves the quality of the leather, for not
-only do the tannin substances exert this tanning action, but the dyewoods
-as well, for they are themselves either of the nature of tannins, or
-contain a coloring principle which is a tannin. It is to the combined
-effects of the tannin substances and the dyewoods that furs dyed with
-vegetable dyes owe their beauty of color, lustre, naturalness of shade,
-permanence of the dyeing, and durability of the leather. Wood dyeings
-on furs have for this reason acquired a just renown, but owing to the
-introduction of the new kinds of fur dyes, the use of the vegetable dye
-substances has been greatly reduced.
-
-The dyes of vegetable origin can be applied to furs by either the brush
-method or the dip method, or both, and since mordants are required
-with the dyes of this class, they are applied in one of the three ways
-mentioned in a previous chapter: first, by mordanting before dyeing;
-second, by applying mordant and dye simultaneously; and third, by
-mordanting after the skins have been treated with the dye.
-
-
-I. DYEING WITH VEGETABLE DYES BY THE BRUSH METHOD
-
-The use of the brush method in applying the natural dyes to furs is
-limited to a comparatively few kinds of dyeing, namely to produce
-special effects on furs, or to give to the upper-hair of furs a coat
-of dye different from the base color. In a quite recent German patent
-is described a process for blending a red fox as a silver fox and
-the procedure affords a good example of brush dyeing with preliminary
-mordanting. The specification is as follows: "D. R. P. 310, 425 (1918).
-A process for dyeing red fox as silver fox. The tanned and dressed skin
-is first superficially decolorized by applying a dilute mixture of milk
-of lime, iron vitriol and alum, with a soft brush so as only to penetrate
-the top-hair. Allow to remain for 4-6 hours, dry, and beat out the dust.
-A dilute solution of iron vitriol is brushed on so as only to wet the
-top-hair, and the skin is thus allowed to remain moist for 12-24 hours.
-Then without drying, a solution of iron vitriol, salammoniac, litharge,
-red argol and wood ashes is brushed on cold with a hard brush so as
-to penetrate all the hair down to very near the skin. The skin has now
-completely lost its red color, and has become a pale yellow. It is now
-ready to be dyed. An infusion of roasted nutgalls, which have been boiled
-for 3-4 hours with water, is applied cold with a soft brush to the upper
-hair. Allow to remain so for 2-3 hours, and without drying, apply a weaker
-solution of the roasted nutgalls with a hard brush so as to saturate the
-hair thoroughly. Dry and beat out. According to the concentration of the
-solution applied, the hair will be colored blue-grey to black, and the
-shade can be varied by varying the strength of the solutions used. The
-different parts of the skin, or those parts of different shades can be
-dyed accordingly."
-
-In this patent all the operations, including killing, mordanting and
-dyeing are done by the brush method, and the process, from this point
-of view is quite similar to one which might have been employed a century
-previous. It is evident that the time and effort required to carry out the
-details as described in the patent would only be warranted in exceptional
-cases, where the value of the dyed fur would be considerably greater than
-that of the natural skin.
-
-An example of the application at the same time of dye and mordant by the
-brush method is the original French Seal dye, which is still employed to
-a limited extent to produce a brilliant, deep, lustrous black topping on
-furs which have already been dyed by the dip process. A typical formula
-for the old French Seal dye is the following:
-
-  Green copperas             10 parts
-  Alum                       10   "
-  Verdigris                  10   "
-  Gall-nuts                  80   "
-  Logwood extract
-    (15 degrees Twaddell)   150   "
-  Water                    1000   "
-
-This mixture is applied to the top of the hair of the furs, after previous
-killing, and the skins allowed to remain moist for several hours, and
-also exposed to the air. The skins are then dried, and beaten out, and if
-necessary a second coat of dye is brushed on. In dyeing seal-imitation
-on muskrat, or skunk-imitation on opossum, for example, the black color
-required on the top-hair, or the upper part of the hair when the furs are
-sheared, can be produced by applying a mixture similar to the above, to
-the furs after they have received their base color by the dip process with
-natural dyes or with the Oxidation Colors. Occasionally, the dyeing is
-given an after-treatment with a dilute solution of sodium bichromate to
-help develop the color, the action in this case being that of an oxidizing
-agent, and not of a mordant.
-
-As far as the third method of mordanting is concerned, that of first
-applying the dye, and then the mordant, it is rarely practised with
-the brush method. The procedure, however, consists in first brushing
-on a solution of the desired dye, then drying and brushing on a mordant
-solution. These operations are repeated perhaps two or three times until
-the proper shade is obtained, exposing the furs to the air for the color
-to be developed.
-
-
-II. DYEING WITH VEGETABLE DYES BY THE DIP METHOD
-
-It was in the application to furs by the dip process that the use of the
-vegetable dyes attained great importance, and although at the present
-time, natural organic dyes have largely been superseded by the Oxidation
-Colors and Aniline Black dyes, yet for certain purposes, and especially
-for the production of blacks, the wood dyes still are able to hold their
-own.
-
-The dyeing of black formerly constituted probably the most important
-branch of the fur dyeing industry, and was undoubtedly the most difficult
-one. For it is possible to obtain as many different kinds of black
-as there are dyers of this color, but only a few certain shades are
-desirable. The division of the classes of furs into those derived from
-the various kinds of sheep, and those obtained from other animals is
-particularly marked in the dyeing of black, and both the composition of
-the dye formulas and the methods of dyeing are somewhat different for
-the two groups. For the dyeing of black on Persian lambs, broadtails,
-caraculs, etc., a combination of logwood and nutgalls with the requisite
-mordants is used, while on hares, Chinese sheep, foxes, raccoons, opossum,
-etc., a mixture of logwood and turmeric or fustic, with the proper
-mordants is used.
-
-The general procedure is as follows: The dye substances to be used are
-ground up to a powder in a mill constructed for the purpose, after which
-they are boiled with water in a copper-lined kettle or cauldron, heated
-from the outside by steam. The customary arrangement is to have a jacketed
-kettle, supported on a stand, and having taps and valves to enable the
-liquor to be drawn off, or pivoted, so that the kettle can be tilted,
-and the contents poured out. The use of the copper-lined vessel is to be
-preferred, as it is unaffected by any of the dye substances, and so cannot
-cause any rust stains. After the dyes have gone into solution and have
-cooled, the mordant chemicals, previously dissolved in water, are added,
-and the mixture stirred up. The dyeing in this instance is effected by the
-simultaneous application of dye and mordant. The dye mixture is now run
-off, or poured out in the proper quantity into a number of small vats of
-25-30 gallon capacity, or into a paddle vat, which can be closed, while
-the paddle is rotating. The latter device is to be preferred because it
-permits the dye to retain its temperature better and for a longer period
-of time, but when lambs are being dyed only the open vats are used. The
-temperature of the dye mixture is between 40° and 45° C., for only at
-this temperature can the hair absorb the dye properly without injuring the
-leather. The killed skins are immersed in the dyebath for a time, usually
-overnight, after which they are removed, drained and hung up, with the
-hair-side exposed to the air, so as to permit the dye to develop, which
-takes place with the aid of the atmospheric oxygen. The dyebath is again
-brought to the proper temperature, and the skins are again entered, to go
-through the same process as often as is necessary to obtain the desired
-depth of shade. The dyed skins are thoroughly washed to remove excess dye,
-then dried and finished. The following are a few dye formulas used in the
-production of blacks:
-
-  Logwood extract       100 grams
-  Chestnut extract       14 c.c.
-  Turmeric               38 grams
-  Iron acetate 6° Bé.    50 c.c.
-  Water                1200 c.c.
-
-or,
-
-  Cutch                  15 grams
-  Soda                   14 grams
-  Logwood extract       120 grams
-  Verdigris              19 grams
-  Iron acetate 5° Bé.    16 c.c.
-  Water                1200 c.c.
-
-A recently published formula for dyeing China goat skins black, is the
-following:
-
-Dissolve 50 lbs. of dark turmeric and 45 lbs. of logwood extract and
-make up to 300 gallons of solution, at 95° F. Enter the killed skins and
-leave them in the liquor until they rise to the surface. Then take them
-out and add 25 lbs. of logwood extract, 10 lbs. of sumach, 10 lbs. of
-blue vitriol, 5 lbs. of fustic extract, and about 60 lbs. of iron acetate
-liquor. Stir up well, and immerse the skins for 18 hours. Draw them up,
-and expose to the air for 12 hours. Heat the liquor again to 95° F. and
-put the skins back for 12 hours. Draw out, hang up in the air for a time,
-then wash thoroughly, hydro-extract, dry and finish.
-
-In a German patent, D. R. P. 107,717 (1898), is described a method for
-dyeing lambs black, consisting in treating the skins for 24 hours in a
-logwood bath, then rinsing in cold water, and mordanting for 15 hours in
-a solution of bichromate of potash. The skins are then washed and treated
-with a solution of iron salt, then dried. This process, while of not much
-practical importance, is an illustration of mordanting subsequent to the
-dyeing treatment.
-
-As far as the production of other shades is concerned, the procedure is
-quite similar to the regular black method. For a dark brown, for example,
-the skins are dyed in a mixture containing
-
-  Gall-nuts                  40 parts
-  Verdigris                  10   "
-  Alum                       10   "
-  Copperas                    5   "
-  Brazilwood extract
-    (15° Twaddell)          150   "
-  Water                    1000   "
-
-employing operations just as in the case of the black.
-
-Greyish-blue shades on white hares, lambs, kids, etc., can be obtained by
-treating the skins successively in the following baths:
-
-  1. Logwood extract  100 grams
-     Water              1 liter
-  2. Indigotine        10 grams
-     Alum              10 grams
-     Water              1 liter
-
-Bluish-grey tones on the same furs can be produced by treating with
-
-  1. Logwood extract  200 grams
-     Indigotine        15 grams
-     Water              1 liter
-  2. Alum             150 grams
-     Salammoniac       12 grams
-     Water              1 liter
-
-Similar grey shades can be produced by mordanting the skins with an iron
-salt, and then dyeing in a weak bath containing gall-nuts, sumach and iron
-vitriol. This method is very effective for making Alaska or silver fox
-imitations.
-
-
-
-
-CHAPTER XIV
-
-FUR DYEING
-
-ANILINE BLACK
-
-
-Fur seal for a long time has been a fur of distinction and importance in
-the fur industry, and consequently the dyeing of seal has constituted an
-important, though not very extensive branch of the art of fur dyeing.
-In quite recent times the popularity of seal has become so great that
-imitations have had to be produced to help supply the demand, and as a
-result, French seal, or seal-dyed rabbit, and the so-called Hudson seal,
-which is seal-dyed muskrat, have acquired a great vogue. Occasionally
-opossum, nutria and other furs are also used for the purpose of producing
-seal imitations. While the supply of real seals is relatively small, and
-the demand large, the production of seal imitations has assumed large
-proportions, and as a result, the dyeing of seal and its imitations or
-substitutes has come to be a great branch of the fur dyeing industry.
-
-During the past thirty years, the long and tedious processes of dyeing
-seal and seal imitations, involving the use of dyes of vegetable origin,
-have largely been superseded by what is known as the Aniline Black dye.
-It was the French who first worked out successfully the application of
-Aniline Black to furs, and the method has attained much importance and
-extensive use in the fur dyeing industry.
-
-Aniline Black is the name given to an insoluble black dyestuff produced
-by the oxidation of aniline in an acid medium. As a finished product it
-cannot be used in fur dyeing, but if the hair of the furs be impregnated
-with a suitable preparation of aniline and then treated with certain
-oxidizing agents, the color will be formed on the hair, being firmly
-fixed and giving a fast black, resistant to light, washing and rubbing.
-The basis of the dye, aniline, is an oily liquid, possessing a peculiar
-fishy odor, colorless when pure, but rapidly turning brown when exposed to
-the air. It is obtained from benzol, which is distilled from coal-tar, by
-treating with nitric acid, forming nitrobenzol, which when subjected to
-the action of reducing chemicals is converted into aniline. The process
-may be shown schematically as follows:
-
-Coal--coal-tar--benzol--nitrobenzol--aniline oil--Aniline Black. Aniline
-Black was by no means a new dye when the French succeeded in producing it
-on furs. It had been used for a long time previous on textiles, chiefly
-cotton. The history of the development of the Aniline Black process
-throws considerable light on its nature and constitution, and so presents
-many features of interest. As early as 1834, the chemist Runge observed
-the formation of a dark green color when heated aniline nitrate in the
-presence of cupric chloride. Fritsche, in 1840, noticed that when chromic
-acid was added to solutions of aniline salt, a dark green, and sometimes a
-blue-black precipitate was produced, and later the same chemist obtained
-a deep blue by the action of potassium chlorate on aniline salt. It is
-interesting to note that Perkin, in 1856, conducting similar experiments
-on the oxidation of aniline with chromic acid, obtained a blue-black
-product from which he extracted the first synthetic coal-tar dye, mauve.
-Thus far, all the experiments on the oxidation of aniline proved to be
-merely of scientific interest, but in 1862, Lightfoot patented a process
-for the practical application of colors formed by the oxidation of aniline
-on the fibre, a greenish shade being obtained by that method, to which the
-name emeraldine was given, and by subsequent treatment with bichromate
-of potash, the green was changed to a deep blue color. Since that time,
-the methods for producing and applying Aniline Black have been developed
-and improved, although all the processes were based on the principles
-incorporated in Lightfoot's original patent. However, it was not until the
-last decade of the nineteenth century that the dyeing of furs by means of
-the Aniline Black method was successfully attempted.
-
-A knowledge of the nature and the manner of the chemical changes which
-take place in the production of Aniline Black is a valuable aid in
-obtaining satisfactory results in practise; and although Aniline Black
-was extensively used before the true character of the reaction was
-understood, since the successful determination of the constitution of
-Aniline Black and the discovery of the real nature of the process by
-Green and his collaborators in 1913, the methods have been considerably
-improved and simplified, with correspondingly better results in dyeing.
-As a consequence, the methods of dyeing furs with Aniline Black have also
-become simpler and more efficient.
-
-A discussion of the chemical changes which occur in the Aniline Black
-process, is out of place here on account of the highly involved and
-complicated character of the reactions, to understand which requires a
-considerable knowledge of specialized organic chemistry. But the essential
-features of practical importance in the production of Aniline Black are
-the following: As already noted, one of the characteristic properties of
-aniline is its tendency to turn from a colorless to a dark-brown liquid in
-the presence of the air. This change is due, together with certain other
-causes, to an oxidation brought about by atmospheric oxygen. By employing
-oxidizing agents, this oxidation can be accelerated and carried further,
-and eventually the Aniline Black is obtained. Among the substances which
-may be used to bring about the conversion of aniline to the insoluble
-black dye are manganese dioxide, lead peroxide, hydrogen peroxide, chromic
-acid, ferric salts, potassium permanganate, chloric acid and chlorates
-in the presence of certain metallic salts, particularly those of vanadium
-and copper. Chlorates, especially sodium chlorate and potassium chlorate,
-are the most commonly employed oxidizing agents, bichromate of soda or
-of potash being used, in addition, to complete the oxidation. When using
-chlorates it is necessary to have present in the dye mixture a small
-quantity of a metallic salt, which, while not entering into the reaction
-itself, is nevertheless indispensable as an oxygen carrier. Vanadium
-compounds have proved to be the most effective for this purpose, and
-according to an authority, one part of vanadium salt is sufficient to
-cause the conversion of 270,000 parts of aniline to Aniline Black, the
-necessary amount of a chlorate being present of course. Salts of copper,
-cerium, and iron are also extensively used, but they are not quite so
-efficient as vanadium.
-
-The formation of the Aniline Black in practise takes place in three
-well-defined steps, which it is important to be able to recognize and
-distinguish in order to obtain the best results. The first stage of the
-oxidizing process produces what is called emeraldine, which in the acid
-medium of the aniline bath is of a dark green, while in the free state it
-is of a blue color. As the oxidation proceeds, the second stage develops,
-the emeraldine being converted to a compound called nigraniline. This in
-acid solution is blue, and the free base is a dark-blue, almost black.
-It was formerly considered that the nigraniline was the Aniline Black
-proper, and so when this stage of the oxidation was reached, the process
-was often interrupted and not carried to the limit. This can account for
-the fact that Aniline Black dyeings usually turned green after a short
-time. The reason for this is that nigraniline, when treated with weak
-reducing agents, as, for example, sulphurous acid, is at once changed
-to emeraldine, with its dark green color. Since there is usually a small
-amount of sulphurous acid in the air, especially in places where coal or
-gas is burned, an Aniline Black dyeing which has not been carried beyond
-the nigraniline stage will be reduced in time to the emeraldine, and cause
-the dyeing to become green. The last step in the oxidation changes the
-nigraniline into what is properly called the ungreenable Aniline Black.
-Weak reducing substances like sulphurous acid do not change this compound
-to emeraldine, and stronger reducing agents only convert it to a brownish
-compound, which changes back to the black when exposed to the air. It is
-quite evident that in order to obtain a black which will not change to
-green in time, the oxidation of the aniline must be carried to the last
-stage. By making tests during the dyeing of the furs, it can easily be
-determined whether the oxidation has proceeded far enough.
-
-In the dyeing of textiles with Aniline Black, it is customary to carry
-out the operation at comparatively high temperatures, approaching 100°
-centigrade. With furs such temperatures are out of the question, so it is
-necessary to repeat the dyeing several times in order to obtain the proper
-depth of shade working in the cold. Only the brush method can be used in
-applying the Aniline Black dye to furs, on account of the strong acidity
-of the dye mixture, which would ruin the leather, if the dyeing were done
-in a bath. Indeed, great care must be exercised even by the brush method
-to avoid too great penetration of the dye liquid, otherwise the roots
-of the hair will be attacked, and the leather may be "burned" from the
-hair side. Furs dyed with Aniline Black are frequently after-dyed by the
-dip-process with logwood or some other similar dye, in order to add to
-the brilliancy of the dyeing. Combined with intensity of color, Aniline
-Black on furs is the only dye which will also give fast, lustrous shades,
-and leave the hair soft and smooth.
-
-There are several methods of applying Aniline Black on furs, the most
-important being
-
-  1. One-bath Aniline Black
-  2. Oxidation Aniline Black
-  3. Diphenyl Black
-  4. Aniline Black by Green's Process
-
-
-1. _One-bath Aniline Black_
-
-A typical formula for this method is the following given by Beltzer:
-
-  Aniline salt            10 kg.
-  Sodium chlorate        1.5 kg.
-  Copper sulphate        0.7 kg.
-  Vanadate of ammonia     10 gr.
-
-All these substances are dissolved hot in 50 liters of water, and allowed
-to cool, forming solution A. Aniline salt is aniline oil which has been
-neutralized with the exact quantity of hydrochloric acid to form the
-hydrochloride. It forms white or greyish crystalline lumps very easily
-soluble in water. The sodium chlorate is the oxidizing agent, and the
-copper sulphate and the vanadate of ammonia are the oxygen carriers.
-
-15 kg. of sodium bichromate are also dissolved in 50 liters of water,
-forming solution B. The bichromate is also an oxidizing agent and serves
-to complete the oxidation of the aniline to the black.
-
-Immediately before using, solutions A and B are mixed together, both being
-cool. In general practise it is customary to mix only small quantities
-at a time, as a considerable precipitate forms when the whole batch
-is mixed at once, the precipitate being so much waste dye substance.
-Usually a liter of A and a liter of B are mixed at a time, and the furs
-brushed with the mixture. The brushing must be varied according as the
-hair is hard and stiff, or soft and tender. The hair must be thoroughly
-impregnated in all directions, and the penetration must not be too deep
-to affect the leather. With experience and dexterity satisfactory results
-can easily be achieved. After the skins have been properly treated, they
-are dried at a temperature of about 35 degrees centigrade. When dry, they
-are returned to the dye bench, where they receive another application
-of the dye mixture, and are again dried. This operation may be repeated
-as often as six or seven times before a sufficiently intense black is
-obtained. Another way of producing the desired depth of shade with fewer
-applications is by using more concentrated dye mixtures. Each method
-has its disadvantages, the greater number of brushings requiring the
-expenditure of more time and labor, and the greater concentration of
-the bath resulting in a considerable loss of dye substance due to the
-formation of a large precipitate when the two solutions are mixed, and
-moreover, not all furs can be treated with concentrated mixtures. The best
-results with this method usually require the application of six coats of
-a mixture of moderate concentration.
-
-
-2. _Oxidation Aniline Black_
-
-In order to overcome the difficulty of employing very concentrated dye
-mixtures, or of making many applications of the dye, a method was devised
-whereby the two solutions of the previous process, instead of being mixed
-together, are applied successively to the hair of the furs, the following
-formula, also by Beltzer, being an example:
-
-  Aniline oil                     10 liters
-  Nitric acid 36° Beaumé, or
-  Hydrochloric acid 22° Beaumé    20 liters
-  Cold water                      20 liters
-
-This is solution A, and is merely a solution of aniline hydrochloride,
-or nitrate, depending on which acid has been used. Nitric acid, although
-more costly than the hydrochloric acid, is to be preferred, because it
-is an oxidizing acid, and so assists in the oxidation of the aniline, and
-besides, has a more beneficial effect on the hair than the hydrochloric,
-in the matter of softness and luster.
-
-  Sodium chlorate          4 kg.
-  Copper sulphate          1 kg.
-  Vanadate of ammonia     10 gr.
-  Water                   50 liters
-
-This is solution B, containing the oxidizing agent, and the oxygen
-carriers. Just before using, equal quantities of A and B are mixed, and
-the skins brushed with the mixture. The skins are then dried at 35-45°
-centigrade, at which temperature the color begins to develop. When almost,
-but not entirely dried, the skins are subjected to the action of warm
-vapor, which is allowed to enter the drying chamber, so as to keep the
-temperature about 40° centigrade, the color developing better in this
-way. This operation may be repeated, or the skins are directly treated
-with a solution of 25 kg. of sodium bichromate in 100 liters of water,
-to complete the oxidation. The moist skins are exposed to the air for a
-time, and then dried at 35° C.
-
-This method of dyeing has several advantages over the One-bath Aniline
-Black. It requires fewer brushings, and enables the complete utilization
-of the dye solutions without loss. With three applications of the dye
-mixture by the Oxidation process, as deep and intense a black can be
-obtained as with six brushings by the One-bath method. The dyeings, too,
-are nearly, but not fully as brilliant and even as in the latter case.
-The greater the number of coats of dye that are applied the more regular
-will the dyeing be.
-
-
-3. _Diphenyl Black_
-
-In 1902, the Farbwerke Hoechst, a large German producer of coal tar
-intermediates and dyes, invented an Aniline Black process to which they
-gave the name Diphenyl Black. The chief departure from the previous
-Aniline Black methods was the replacing of part of the aniline oil of the
-dye mixture by Diphenyl Black Base I, which is para-aminodiphenylamine.
-This base has the property of being oxidized to Aniline Black, just like
-aniline oil, and the advantage claimed for the Diphenyl Black is that it
-produces an absolutely ungreenable black. The method of application is
-practically the same as for the other Aniline Black processes, chlorates
-being used as the oxidizing agents, in the presence of oxygen carriers
-such as salts of copper and vanadium. The use of bichromates is dispensed
-with. On account of the comparatively high cost of the Diphenyl Black
-Base I, this method has not found very extensive application, especially
-as highly satisfactory ungreenable blacks can now be produced by other
-methods.
-
-
-4. _Aniline Black by Green's Process_
-
-In 1907, Green, who has done much work in the direction of elucidating the
-character of the Aniline Black process, obtained a patent for a method
-of applying Aniline Black in a manner which was different from all the
-previously known formulas. The invention created great interest, and
-although in its original form it did not find a wide application, many of
-the methods used at the present time are in one way or another derived
-from the idea of Green. A resumé of the patent will therefore be given
-here: "The invention relates to the production of an Aniline Black, the
-new process differing from all other known processes by the fact that
-the oxidation of aniline is effected solely or mainly by the oxygen of
-air. The possibility of dispensing with an oxidizing agent depends on the
-discovery that the addition of a small quantity of a para-diamine, or of
-a para-amido-phenol to a mixture containing aniline and a suitable oxygen
-carrier, such as a salt of copper, greatly accelerates the oxidation of
-the aniline by the atmospheric oxygen. Further, whereas in the ordinary
-processes of Aniline Black, the quantity of mineral acid employed cannot
-be materially reduced below the proportion of one equivalent to one
-equivalent of the base, under the new conditions the mineral acid may
-be wholly or partially replaced by an organic acid such as formic acid,
-without the quality of the black being materially affected. As suitable
-oxygen carriers the chlorides of copper have been found to give the best
-results, it being preferrable to use the copper in the form of a cuprous
-salt. This is effected by adding to the dye mixture cupric chloride,
-together with a sulphite or bisulphite in sufficient quantity to reduce
-the cupric salt to the cuprous state, and a sufficient quantity of a
-soluble chloride to keep the cuprous chloride in solution. Among the
-compounds suitable for the production of this black in conjunction with
-aniline are, para-phenylene-diamine, dimethyl-para-phenylene-diamine,
-para-amido-diphenylamine, para-amido-phenol, etc."
-
-This method may be used alone as the other Aniline Blacks, or the dyed
-skins may be after-dyed in a bath containing a logwood dye, or it may be
-used in conjunction with mineral dyes, or with the Oxidation Colors (see
-next chapter). A typical formula for the black by Green's process is the
-following:
-
-  Para-amido-phenol            0.5 kg.
-  Aniline oil                   10 liters
-  Hydrochloric acid 22° Bé.     10 liters
-  Acetic acid 40%                5 liters
-  Cold water                    25 liters
-
-This is solution A. Solution B is prepared by dissolving
-
-  Copper sulphate       2 kg.
-  Salammoniac          10 kg.
-  Cold water           50 liters
-
-A and B are mixed, and the mixture applied to the hair of the furs several
-times, drying each time at 35°-40° C. After three coats of dye have
-been applied, a pretty and fairly intense black shade is obtained, which
-is developed further by treating with a solution of 25 grams of sodium
-bichromate per liter of water. The skins are then allowed to dry in air,
-and then if desired, an after-dyeing is made with some other dye.
-
-On account of its extreme fastness, Aniline Black, produced by any of
-the methods outlined above, has attained a justifiable popularity for
-the dyeing of furs, in spite of the necessity of using the more or less
-cumbersome brush method of applying the dye. Very recently there was
-issued to a German company a patent in which is described a method whereby
-furs can be dyed with Aniline Black by the dip process. An abstract of
-the patent (D. R. P. 33402) is as follows: "As is known, aniline salt,
-and similar salts, together with oxidizing agents like bichromates,
-chlorates, etc., cannot be used for dyeing furs by the dip process,
-because the strongly dissociated mineral acid is injurious to the leather.
-The dissociation of the acid can be reduced by adding neutral salts, like
-common salt, or Glauber's salt, so that good results can be obtained by
-dyeing in a bath of the dye mixture, the leather retaining its softness."
-
-Thus far there have been no reports of the successful practical
-application of this patent, so its value cannot be discussed. It is
-extremely doubtful, however, that furs will ever be dyed in the dyebath
-with the present type of Aniline Black formulas, no matter what substances
-are added to prevent the leather from being affected.
-
-
-
-
-CHAPTER XV
-
-FUR DYEING
-
-OXIDATION COLORS
-
-
-The year 1888 may be considered the beginning of a new era in the
-history of fur dyeing; the commencement of a period which was to see
-the time-honored, traditional methods of the masters of the art give way
-to newer methods of an entirely different character; and moreover, the
-initiation of an age when science with its basis of fact and logic, was
-to undertake the rationalization of an industry which had hitherto worked
-upon a more or less irrational, empirical and uncertain comprehension
-of the fundamental principles involved. It was not the work of a single
-day, or even of a year which brought about the virtual revolution in the
-dyeing of furs, but the result of long, patient, systematic effort. About
-this time, the German coal tar industry was attaining its real stride
-along the path of progress and achievement, and had already succeeded in
-reaching, to an appreciable degree at any rate, most users of coloring
-matters, with the consequence that the natural dyes, with their time and
-labor-consuming processes of application were gradually being superseded
-by the new synthetic dyestuffs which could be simply and quickly applied.
-It was now the turn of the fur dyeing industry to receive the attention of
-the scientists and technologists responsible for the growth of the coal
-tar dye industry, and so there appeared in the above-mentioned year, the
-following patents, taken out by a German chemist named Erdmann:
-
-
-D. R. P. 47349
-
-A Process for Dyeing Hair and Feathers
-
-If white hair or feathers are soaked in an aqueous or alcoholic solution
-of para-phenylene-diamine, and then exposed to the slow oxidation of
-the air, or are treated in a second solution with some oxidizing agent,
-then the hair or feathers will be dyed. According to the oxidizing agent
-chosen, and the concentration of the solution used, the color obtained
-will be light or dark, varying from the palest blond to the deepest
-blue-black. Particularly suitable as oxidizing substances are ferric
-chloride, permanganates, chlorates, hypochlorites, bichromates, and
-hydrogen peroxide. The dyeings are fast, that is, they do not come off,
-and the color cannot be removed by washing. Following examples may serve
-to make the process clear:
-
-20 grams pure para-phenylene-diamine and 14 grams caustic soda are
-dissolved in a liter of water. The hair, previously degreased, is soaked
-thoroughly in this solution, and while moist is entered into a three per
-cent solution of peroxide of hydrogen. The action is not instantaneous,
-but after a day, the hair is dyed a dark shade; by repetition of these
-operations a blue-black is obtained.
-
-The para-phenylene-diamine can be replaced in this process by other
-similar bases, such as dimethyl-para-phenylene-diamine, as well as the
-naphthylene-diamines. Since the substances which can be applied by this
-process are uninjurious, the method described can be used to dye human
-hair on the head or beard, and so seems suited to replace for the dyeing
-of hair, the metallic salts and various pyrogallic solutions which are on
-the market, and which are harmful to the health.
-
-
-D. R. P. 51073 Supplement to 47349; Process for Dyeing Hair
-
-This patent was an extension of the original patent to include certain oxy
-and amido-oxy compounds, the method being essentially the same otherwise
-as in the original patent. An illustration of the process is as follows:
-
-73 grams para-amido phenol hydrochloride are dissolved with 40 grams
-caustic soda in a liter of water. The solution dyes hair a golden-yellow,
-which on subsequent treatment with a solution of ferric chloride turns to
-a red-brown.
-
-In these two patents is to be found the basis of the modern fur dyes
-and fur dyeing methods. It is interesting to note that furs were not
-mentioned at all in connection with the process, which was intended
-mainly for dyeing hair, especially on the human head. It was only several
-years later that the value of the method for dyeing furs was realized.
-So about 1894, the Aktien Gesellschaft für Anilinfabrikation put upon
-the market three fur dyes under the trade name Ursol, Ursol D, giving
-dark-brown to black shades; Ursol P, giving red-brown colors; and Ursol
-C, giving a yellowish-brown shade. Pyrogallic acid had been previously
-used as a hair dye, and also to a slight extent as a fur dye, so it was
-used in conjunction with the Ursol dyes for shading purposes. The new fur
-dyes were not dyes in the ordinarily accepted sense of the term. They
-were really coal-tar intermediates, substances similar in character to
-aniline, and their dyeing property depended on the fact that they could
-be oxidized either by atmospheric oxygen, or by means of oxidizing agents,
-forming colored insoluble products. When the oxidation of the intermediate
-was caused to take place on the hair the colored product formed on and
-in the hair fibre, and remained fast. The reactions bringing about the
-conversion of the intermediate to the colored insoluble compound are quite
-analogous to those of the Aniline Black process, though possibly not so
-complicated, with the important difference, however, that, while in the
-production of Aniline Black acid is essential, in the present instance the
-oxidation can be carried on in neutral or even alkaline medium. On account
-of the character of the method used in applying the new fur dyes, the
-name Oxidation Colors has been given to them. Strictly speaking, Aniline
-Black is also an Oxidation dye, but it is usually considered in a class
-by itself. The methods used at first in the application of the Ursol dyes
-to furs followed closely the process as described in the patents. The furs
-were first killed, usually by brushing on a lime mixture, drying, and then
-beating out the dust. This operation was repeated, if necessary. Then a
-solution of the desired dye, mixed with an equal volume of 3% peroxide of
-hydrogen was brushed on and the fur allowed to lie exposed to the air. The
-dyeing could also be done by the dip process, less concentrated solutions
-being used. By varying the concentration of the solution, and prolonging
-or shortening the time of action, the shades could be varied from very
-light to very dark, and by combining two or more of the Oxidation Colors,
-many different color effects could be produced. Soon other fur dyes were
-developed and put on the market; for example, Ursol DB, giving blue to
-blue-black shades, and Ursol 2G, yielding yellowish tones suitable for
-mixing with the other colors. Ursol C was discarded shortly after its
-introduction. The dyeings obtained with the Oxidation Colors seemed to be
-very fast, resisting successfully the action of cold or hot water, or even
-hot soap solution. Moreover, a dyed hair examined under the microscope
-appeared to be colored through the epidermis to the medulla, and no
-individual particles of dye could be discerned.
-
-The new fur dyes had many evident advantages over the coloring matters
-in general use at the time. The simplicity of the dyeing operations,
-the short duration of the process, the great tinctorial power of the
-new products, were facts which strongly recommended themselves to the
-progressive fur dyer. The cost of the dyes was higher than that of the
-vegetable dyes, but this consideration was largely overbalanced by the
-saving in time and labor in using them. And yet, the Ursol dyes found
-only a comparatively small market. The majority of fur dyers, always
-conservative and reluctant to turn from the traditional ways of the
-industry were skeptical of, and even hostile towards the new dyes and
-the new methods of dyeing. In a sense, this opposition was justifiable.
-It was not an easy task to relinquish all at once methods which had
-been successfully applied for generations back, and with which they
-were thoroughly experienced, in favor of processes which were radically
-different, and with which they had no experience at all. But some
-enterprising spirits among the fur dyers undertook to try out the new
-products and it was not long before the skeptics had good cause for
-condemning the work and achievements of the chemists as far as fur dyeing
-was concerned. The new type of dyes did possess some of the advantages
-claimed for them, but they also possessed many highly objectionable
-features, which had never been manifest with the vegetable dyes. First
-of all, the dyeings were not so fast as had at first appeared, for the
-color came off the hair when the furs were rubbed, brushed or beaten.
-Then it was observed that after a short time some of the dyeings changed
-color, and at the same time the hair lost its gloss and became brittle.
-The condition of the leather after dyeing was anything but satisfactory.
-Most serious of all, however, was the appearance among the workers in
-the dyeing establishments, and also among the furriers who worked with
-the dyed skins, of certain pathological conditions which had hitherto
-been unknown. Various skin diseases, eczemas, inflammation of the
-eyes, asthmatic affections and intestinal irritations were some of the
-afflictions which were directly attributable to the use of fur dyes of
-the Ursol type. Medical science was at a loss to know how to treat these
-ailments, because their nature was not understood.
-
-Here indeed, were obstacles threatening to destroy all the hopes which
-the discovery of the new class of dyes had aroused, and to check at the
-outset the possibility of rational progress in the fur dyeing industry.
-But the men of science were not content to let the matter drop thus.
-Difficult problems had been solved before, and surely there must be
-some way of overcoming the objections and deleterious features of a
-system of fur dyeing which had so much potential merit. Where hindrances
-sprang up in the path of progress, it was the duty of the chemist to
-remove them, and when difficulties arose, it was up to him to resolve
-them, as far as was humanly possible. So the chemists who had been
-responsible for the introduction of the Oxidation Colors set themselves
-to the task of eliminating the undesirable or injurious qualities. It
-was many years before the results of painstaking effort and persistent
-study cleared up the causes of all the objectionable aspects of the fur
-dyes, and suggested means of overcoming them satisfactorily. The work
-had been directed to the improvement of the dyes and of the methods of
-dyeing with them. Purer intermediates were produced, and more easily
-soluble ones, so that there would be no possibility of ultra-microscopic
-particles of the dye being deposited on the surface of the hair from the
-dye solution, instead of being taken up within the hair fibre. It was
-this superficial deposition of minute crystals of the dye or of the only
-partially oxidized intermediate, on the hair, crystals so fine as to be
-invisible in the ordinary high-power microscope, which caused the color
-to come off when the furs were brushed or beaten, giving rise to a dust
-which was frequently very injurious to the health. Then, mordants were
-adopted to help fix the dyes, compounds of copper, iron, and chromium
-being used as formerly with the vegetable dyes, and the range of shades
-was also increased thereby. Certain of the Oxidation Colors had a tendency
-to sublime off the hair, so the dyed hair was chemically after-treated
-in such cases to prevent this. The causes of the pathological aspects of
-dyeing with the Oxidation fur dyes were not so readily disposed of. But
-the adoption of devices to prevent the formation and circulation of dust
-during the handling of the dye, the employment of adequate protection
-against contact with the dye or its solutions, the use of the most dilute
-solutions possible in dyeing, the thorough washing of the dyed skins to
-remove any excess of the coloring matter, the prevention of dust formation
-in the drying of the skins, and the rigid observance of, and adherence to
-hygienic laws, were all factors in the elimination of the health-impairing
-phases of dyeing with the Oxidation Colors.
-
-It was only after all these improvements had been accomplished that the
-fur dye intermediates began to acquire a degree of popularity among fur
-dyers, and strange as it may seem, there was a more ready market for
-these dyes in America, than in Germany where they were manufactured. Other
-manufacturers of coal-tar intermediates also began to produce fur dyes,
-and so, in addition to the Ursols, there were the Nako brand, the Furrol
-brand, the Furrein brand, and one or two others. New dyes were invented,
-until the whole range of colors suitable for fur dyeing had been produced.
-The black dye, however, presented some difficulty. A black dye which would
-rival logwood blacks could not be attained. Ursol DB in conjunction with
-Ursol D was being used to produce bluish-blacks, but the dyeings were not
-fast, turning reddish after a time. In 1909, a patent was taken out for
-a dye mixture, which was made up like the DB brand, but instead of using
-toluylene diamine with para-phenylene-diamine, the new dye was made up of
-a methoxy, or ethoxy-diamine with para-phenylene-diamine, and it yielded
-brilliant bluish-blacks, which were fast, and which very nearly approached
-the logwood black in luster, intensity, and bloom. For some purposes,
-however, the production of a black color is still dependent on the use of
-the logwood dye.
-
-When the Great War cut off to a large degree the importation of skins
-dyed in Europe, the American fur dyeing industry developed tremendously,
-and in a comparatively short time was able satisfactorily to accomplish
-in the way of dyeing furs, what had taken foreign dyers a much longer
-period to attain. It had been previously considered that furs could be
-dyed properly only by European fur dyers, but the achievements in this
-direction by Americans fully dispelled this belief. But the success of
-the fur dyers in America might not have been so marked or rapid, had it
-not been for the work of the American chemists. The war had also shut off
-the supply of German dyes, upon which the dyeing industries of America
-had formerly been dependent, so enterprising chemists in this country
-undertook to fill the need, and in a surprisingly short time, American fur
-dyes, in every respect the equal of the foreign product were offered to
-the American fur dyers, and at the present time, the requirements of the
-fur dyeing industry in this country are being adequately met by domestic
-producers. Among the brands on the market are the Rodol, Furamine,
-Furol, and several others. The Oxidation Colors are now being offered
-in a high state of purity, and easily soluble, free from any poisonous
-constituents, and there is absolutely no reason for the appearance of
-any pathological conditions among workers on dyed furs, or users of such
-furs, provided the necessary precautions have been taken in the dyeing
-process. The occurrence of any affection which can be traced to dyed fur,
-cannot possibly be due to the dye itself, but to gross carelessness and
-negligence in dyeing, and in any such event, the dyer responsible should
-be brought to account.
-
-In order to get a better understanding of the nature and action of the
-Oxidation Colors, a typical one will be studied in some detail. The most
-important one in this class is para-phenylene-diamine, usually designated
-by the letter D in all commercial brands of this fur dye, while its
-chemical formula is represented as C{6}H{4}(NH{2}){2}. When pure it occurs
-in colorless, crystalline lumps, which rapidly turn brown when exposed
-to the air; the technical product of commerce is of a dark-brown color.
-It dissolves readily in hot water when pure, and also in acids. At one
-time the hydrochloride was used instead of the free base, on account
-of its greater solubility, but now a base is made which is sufficiently
-pure to be very soluble in water. There are several methods of preparing
-para-phenylene-diamine: first, by the reduction of amido-azobenzol,
-the product obtained in this way always containing a slight amount of
-aniline, which reduces the solubility, and also gives rise to poisonous
-oxidation products during the dyeing process; second, by the reduction
-of paranitraniline, the quality and solubility of the product in this
-case depending on the purity of the starting material; and third, by the
-treatment of para-dichloro-benzol with ammonia under pressure, the best
-product being obtained by this method. The crude para-phenylene-diamine,
-made by any of the above processes, is generally distilled in vacuo, the
-refined base being obtained as lumps with a crystalline fracture.
-
-The first step in the oxidation of the para-phenylene-diamine is the
-formation of quinone di-imine, NH:C{6}H{4}:NH. This is a very unstable
-compound in the free state, and even in aqueous solution it decomposes
-within a comparatively short time, or combines with itself to form a more
-stable substance. Quinone di-imine has a very sharp, penetrating odor, and
-produces violent local irritations wherever it comes in contact with the
-mucous membrane. If a small quantity of para-phenylene-diamine is absorbed
-into the human body, by breathing the dust, or otherwise, the formation
-of quinone di-imine takes place internally with consequent irritation of
-the mucous lining throughout the body. The various pathological conditions
-mentioned before may be ascribed to irritation caused by quinone
-di-imine. In any dyeing process where there is a possibility of the
-formation of quinone di-imine, as is the case with most dyes containing
-para-phenylene-diamine, special precautions must be taken by the workers
-in handling the dye or coming in contact with its solutions, and no one
-who is particularly sensitive to irritation should be permitted to work
-in a place where such dyes are used.
-
-The next step in the oxidation of the para-phenylene-diamine is the
-formation of what is called Bandrowski's base. Three parts of the quinone
-di-imine combine with themselves, forming a substance of a brown-black
-color, which was formerly regarded as the final oxidation product. The
-formula of Bandrowski's base is represented by the following chemical
-hieroglyphics:
-
-  (NH{2}){2}.C{6}H{3}.N:C{6}H{4}:N.C{6}H{3}(NH{2}){2}.
-
-Further investigation has shown that the oxidation proceeds beyond this
-stage with the formation of a compound of what is known as the azine type,
-which is depicted by the chemist as
-
-                   NH          NH
-  (NH{2}).C{6}H{3}<  >C{6}H{2}<  >C{6}H{3}.NH{2}.
-                   NH          NH
-
-It is by no means certain that this substance is the true coloring matter
-obtained by the oxidation of para-phenylene-diamine, for the reactions
-may continue still farther, producing even more complicated oxidation
-products. Scientific research and study has not as yet gone beyond this
-stage.
-
-The reactions of the other dyes of the Oxidation type are quite similar to
-those of para-phenylene-diamine, some being simpler, and others being even
-more complex. The presence of certain chemical groups in the intermediate,
-or the relative position of such groups are factors responsible for the
-variations in shade.
-
-With the various mordants, the Oxidation Colors give different shades, and
-a great range of colors can be produced either by combining mordants, or
-combining dyes, or both. The following tables illustrate the shades formed
-with the customary mordants.
-
-  =========================================================================
-           |    CHROME     |     COPPER     |     IRON     |    DIRECT
-  ---------+---------------+----------------+--------------+---------------
-  Ursol D  | brown black   | coal black     | coal black   | dark brown to
-           |               |                |              |   brown black
-  Ursol P  | dull red brown| dull dark brown| grey brown   | light brown
-  Ursol 2G | yellow brown  | dull yellow    | yellow brown | dull yellow
-           |               |   brown        |              |
-  Ursol A  |    ...        |     ...        | blue black   | blue to blue-
-           |               |                |              |   black
-  Ursol 4G | light brown   | medium brown   | yellow       | pure yellow
-  Ursol 4R | orange brown  | light yellow   | red brown    | orange red
-           |               |   brown        |              |
-  Ursol    |               |                |              |
-    Grey B | greenish grey | greenish grey  | mouse grey   |     ...
-  Ursol    |               |                |              |
-    Grey R | brownish grey | brownish grey  | reddish grey |     ...
-  ---------+---------------+----------------+--------------+---------------
-
-Fur dyes of American make being equal in every way to the German product,
-show the same color reactions with the various mordants. The following
-table shows the shades produced with the same mordants as above:
-
-  =========================================================================
-           |    CHROME     |    COPPER     |     IRON      |     DIRECT
-  ---------+---------------+---------------+---------------+---------------
-  Rodol D  | brown black   | coal black    | coal black    | brownish black
-  Rodol P  | red brown     | dark brown    | grey brown    | light brown
-  Rodol 2G | yellow brown  | yellow brown  | yellow brown  | dull yellow
-  Rodol 4G | light brown   | light brown   | reddish brown | pure yellow
-  Rodol A  |     ...       | blue black    |     ...       | blue black
-  Rodol    |               |               |               |
-    Grey B | greenish grey | greenish grey | mouse grey    |     ...
-  Rodol    |               |               |               |
-    Grey R | greenish grey | brownish grey | mouse grey    |     ...
-  ---------+---------------+---------------+---------------+---------------
-
-All these shades are produced by dyeing in a bath containing a _neutral_
-solution of the dye. Sometimes the dye comes in the form of a salt of
-a mineral acid, like hydrochloric or sulphuric acid, in which case a
-sufficient amount of an alkali, usually ammonia, is added to liberate
-the free base. According to the Cassella Co., German manufacturers of the
-Furrol brand of fur dyes, the dyeing can also be carried on in slightly
-alkaline or in slightly acid solution, a different series of shades being
-obtained in each instance. Ammonia is used to render the bath alkaline,
-and formic acid to make it acid. The most customary practise, however, is
-to use neutral solutions of the dyes.
-
-For preparing the mordant solutions much smaller quantities of the
-metallic compounds are used than in the case of the vegetable dyes. With
-chrome mordants cream of tartar is always employed as an assistant, and
-occasionally also with copper and with iron mordants. With copper, and
-also with iron mordants no addition is made at all, or sometimes a small
-quantity of acetic acid is added. The temperature of the mordant solution
-is kept about 30° C., and the duration of the mordanting varies from 2-24
-hours according to the depth of shade desired. The concentration of the
-solution may also be varied, it sometimes being just as well to use a
-strong mordant solution and less duration of mordanting. Chrome may be
-combined with copper, and iron may be combined with copper, but chrome
-and iron do not go together as mordants. Some typical average mordanting
-formulas are as follows:
-
-         Chrome mordant.
-  Bichromate of soda    2.5 gms.
-  Cream of tartar       1.5 gms.
-  Water                   1 liter
-
-         Copper mordant.
-  Copper sulphate         2 gms.
-  (Acetic acid 50%        2 gms.)
-  Water                   1 liter
-
-          Iron mordant.
-  Ferrous sulphate        2 gms.
-  (Acetic acid 50%        2 gms.)
-  Water                   1 liter
-
-or,
-
-  Iron pyrolignite 30%   10 gms.
-  Water                   1 liter
-
-      Chrome-copper mordant.
-  Bichromate of soda      2 gms.
-  Copper sulphate      0.25 gms.
-  Cream of tartar       1.0 gms.
-  Water                   1 liter
-
-       Copper-iron mordant.
-  Copper sulphate         2 gms.
-  Ferrous sulphate        2 gms.
-  (Acetic acid 50%        2 gms.)
-  Water                   1 liter
-
-The killed skins are immersed in the mordanting solution, and allowed
-to remain the required length of time. They are then thoroughly rinsed
-to remove any excess of the mordant, and are hydro-extracted. Under no
-circumstances should mordanted skins be permitted to dry, for they would
-be unfit for use again.
-
-The dyebath is next prepared by dissolving the necessary quantity of the
-dye, varying from 0.1 gm. to 10 gms. per liter. Then if the solution must
-be neutralized, the ammonia is added and the temperature of the bath is
-brought to 30-35° C. by the addition of cold water. This temperature is
-maintained throughout the dyeing operation. To the solution is added the
-oxidizing agent. Ordinary commercial peroxide of hydrogen containing 3%
-by weight is the usual oxidizer, although perborates have been suggested.
-15-20 parts of peroxide of hydrogen for every part of dye are added, and
-the dye solution brought to the proper dilution. As soon as the dyebath is
-ready, the skins are entered, and worked for a short time to effect even
-penetration. They are then left in the dyebath for 2-12 hours or longer
-according to the depth of shade. After being satisfactorily dyed, the furs
-are rinsed thoroughly, hydro-extracted and dried and finished. Where the
-dye is to be applied by the brush to the tips of the hair, stronger dye
-solutions are used, the brushed skins being placed hair together and let
-lie for about 6 hours in order to permit the color to develop, after which
-the furs are dried and drum-cleaned.
-
-Some shades, particularly black, have a tendency to rub off slightly. In
-order to overcome this, the dyed furs, after rinsing, are treated with a
-cold solution of 1/2 part of copper sulphate per 1000 parts of water, for
-3-4 hours, then without rinsing, hydro-extracted and dried. Furs which
-have been tipped are brushed with a 1-2% solution of copper sulphate and
-dried. Care must be taken in this after-treatment, for the use of too
-strong a solution of copper sulphate, or too prolonged action of such a
-solution will materially alter the shade of the dyed fur.
-
-A few typical formulas will serve to illustrate the general methods of
-employing the Oxidation Colors:
-
-
-_Brown Sable Imitation on Unsheared Rabbit_
-
-The skins are killed with soda, soured, and washed, then mordanted with
-
-  Bichromate of soda      2 grams
-  Copper sulphate       .25 grams
-  Cream of tartar         1 gram
-  Water                   1 liter
-
-for 24 hours. Then washed, and dyed for 24 hours with
-
-  Fur Brown 2G[3]         3 grams
-  Hydrogen peroxide      45 grams
-  Water                   1 liter
-
-Wash and dry the skins, then brush the tips with
-
-  Fur Brown D[3]         20 grams
-  Hydrogen peroxide     400 grams
-  Water                   1 liter
-
-  [3] Inasmuch as most manufacturers use the same letters to designate
-      the various dyes, any equivalent brand of fur dye may be used in
-      place of those here mentioned.
-
-
-_Black on Sheared Muskrat_
-
-The skins are killed with soda, soured, and washed, then chrome mordanted
-for 6 hours. Then they are dyed for 6 hours with
-
-  Rodol P               1.5 grams
-  Pyrogallic acid        .7 grams
-  Ammonia               2.0 grams
-  Hydrogen peroxide      45 grams
-  Water                   1 liter
-
-The dyed skins are washed and dried, then tipped with
-
-  Rodol D                20 grams
-  Rodol DB                2 grams
-  Hydrogen peroxide     450 grams
-  Water                   1 liter
-
-
-_Brown on Thibet Sheep Skin_
-
-The killed skins are mordanted for 6 hours with a chrome mordant, then
-dyed for 6 hours with
-
-  Ursol P                 1 gram
-  Pyrogallic acid         1 gram
-  Ammonia                 2 grams
-  Hydrogen peroxide      40 grams
-  Water                   1 liter
-
-It is also possible to combine dyeings with the Oxidation Colors with
-Vegetable dyeings, or with Aniline Black. For example, if it be desired
-to produce an imitation skunk on a raccoon, and an exceptionally fast and
-intense and lustrous black on the tips of the hair, the skins are dyed
-in the bath with the Oxidation dyes, and the tips of the hair are brushed
-with a mixture such as described under Vegetable Colors for the production
-of French seal, as follows:
-
-
-_Imitation Skunk on Raccoon_
-
-The skins are killed with caustic soda, soured and washed, then mordanted
-with an iron-copper mordant as described, and then dyed with
-
-  Fur Grey R              3 grams
-  Ammonia                 2 grams
-  Peroxide of hydrogen   45 grams
-  Water                   1 liter
-
-After washing and drying, the dyed skins are brushed over with a mixture
-such as used for dyeing French seal with Vegetable Colors.
-
-In a similar manner, the Oxidation Colors may be used to give a base color
-to furs dyed by the Aniline Black process.
-
-It is apparent from these few illustrations that a great variety of shades
-can be produced, and the dyeing of imitations of the better class of furs
-on cheaper skins is a comparatively simple matter, after an understanding
-of the nature of the dyes has been obtained, and a certain amount of skill
-acquired in working with these dyes.
-
-
-
-
-CHAPTER XVI
-
-FUR DYEING
-
-COAL TAR DYES
-
-
-In addition to the Aniline Blacks and the Oxidation Colors already
-discussed there are certain of the synthetic coal tar dyes such as are
-generally used in the dyeing of textiles, which can also be applied on
-furs. There are several classes of these dyes, varying somewhat in their
-nature, and consequently in their manner of application; in the main they
-produce bright shades, such as are but seldom used on furs, yet which may
-occasionally serve for the production of novel effects. Basic, acid and
-chrome colors are the types which can be employed.
-
-Basic colors possess great fullness and tinctorial strength, but have a
-tendency to rub off, and the tips of the hair take a darker shade with
-these dyes than the rest of the hair. The addition of acetic acid and
-Glauber's salt to the dyebath will result in a more uniform dyeing. On
-account of the comparatively poor fastness to rubbing and washing, basic
-dyes are used only for dyeing furs which are intended for cheap carpet
-rugs, such as sheep and goat. They may also find use in the production
-of light fancy shades on other white furs. The procedure is usually as
-follows: The furs are killed in the customary manner with soap and soda
-or ammonia, or if this is insufficient, with milk of lime. A soap-bath is
-then prepared containing 2.5-6 grams of olive-oil soap per liter of water.
-The temperature of the bath is brought to 40° C. To this is added the
-solution of the dyestuffs, prepared by mixing the required color or colors
-with a little acetic acid to a paste, and then pouring boiling water on
-the mixture until dissolved. Undissolved particles or foreign matter are
-removed by passing this solution through a cotton cloth or sieve, and
-the clear solution then mixed with the soap-bath. The well-washed skins
-are then entered into the dyebath and immersed for about half an hour,
-or until the desired depth of shade is obtained. They are then removed,
-pressed or hydro-extracted and dried. For the production of light shades,
-the following dyes may be used:
-
-For cream, light sulphur-yellow, maize, salmon, etc.
-  Combinations of
-  Thioflavine
-  Rhodamine B
-  Irisamine G
-
-For greenish-yellows
-  Combinations of
-  Thioflavine
-  Victoria Blue B
-
-For light pink
-  Rhodamine B
-  Irisamine
-  Rose Bengal Extra N
-
-For purple
-  Methyl Violet 3B-6B
-  Crystal Violet
-
-For sky-blue
-  Victoria Blue B
-
-For white
-  Victoria Blue B (Milk-white)
-  Methyl Violet 3B-6B
-  Crystal Violet (Ivory-white)
-
-To produce very delicate shades, the moist dyed skins are subjected to a
-sulphur bleach overnight, to lighten the color, then rinsed, and dried.
-Full, brilliant shades may be obtained by dyeing in a bath of 40° C.,
-acidulated with 2-3 grams of acetic acid per liter of solution, the
-following dyestuffs being suitable:
-
-For yellow to orange
-  Thioflavine
-  Paraphosphine
-  Rhodamine
-  Safranine
-  New Magenta O
-
-For pink
-  Rhodamine B
-  Rose Bengal Extra N
-
-For light red
-  Safranines
-
-For bordeaux and red
-  Magenta
-  New Magenta
-  Russian Red
-  Cerise
-
-For violet
-  Methyl Violet 6B-4R
-  Crystal Violet 5B
-
-For blue
-  Victoria Blue B
-  Methylene Blue BB
-  New Methylene Blue N
-
-For green
-  Malachite Green Crystals
-  Brilliant Green Crystals, or combinations of
-  Thioflavine
-  Diamond Phosphine
-  Victoria Blue B
-
-For brown
-  Chrysoidines
-  Bismarck Browns
-
-In dyeing skins with harder hair than that of sheep or goat, mere killing
-is insufficient to render the hair capable of taking up the dye. The
-skins are therefore immersed before dyeing, in a cold, weak solution
-of chloride of lime, the affinity of the hair for the dye being thereby
-greatly increased.
-
-Acid dyes are employed when a greater fastness is required than can be
-obtained with the basic colors. Sulphuric acid in a quantity equal to
-half the weight of the dyestuffs used, together with four times that
-quantity of Glauber's salt is added to the dyebath. Formic acid may be
-used in place of the sulphuric acid, very good results being obtained.
-The skins are immersed in the dyebath, and worked until thoroughly soaked
-with the dye liquor, and then allowed to remain until the proper depth
-of shade is attained, or overnight. The temperature of the solution is
-about 40° C., and only very light shades can be produced in this manner.
-In 1900 and again in 1914, the Cassella Co., a large German manufacturer
-of dyestuffs, obtained patents for processes enabling the dyeing of
-furs in hot solution with the acid dyes. The method required that the
-skins be chrome-tanned in order to render them resistant to the action
-of hot solutions, the addition of a small amount of formaldehyde to the
-chrome solution increasing this effect. The skins are then treated with a
-solution of chloride of lime in order to increase the affinity of the hair
-for the dyestuffs. The method as it is now practised is as follows: The
-skins which have been cleaned and washed are chrome tanned by the method
-as described in the chapter on Tanning Methods, 60 grams of formaldehyde
-being added to every 10 liters of the chrome solution. After proper
-tanning the skins are rinsed, and while still moist they are subjected to
-a treatment with chloride of lime. They are first immersed for 15 minutes
-in a cold bath containing 120 grams of hydrochloric acid 32-36° Twaddell
-per 10 liters of water, then without rinsing, they are entered into a bath
-made up by adding gradually in four portions the clear solution of 2-4
-grams of the chloride of lime per 10 liters of water. After working for
-an hour, the skins are removed and entered again into the acid solution,
-in which they are worked for another 15 minutes. In order to neutralize
-and remove the last traces of the chloride of lime from the furs, they are
-rinsed in a luke-warm bath containing 1-2 grams of sodium thiosulphate,
-or hyposulphite of soda, in 10 liters of water. The skins are then rinsed
-again, and hydro-extracted, or pressed, and are ready for dyeing. The
-dyebath is prepared with the required quantity of dye, to which is added
-10-20% Glauber's salt and 2-5% acetic acid (both calculated on the weight
-of the skins). The skins are entered at 20° C., then after three-quarters
-of an hour to 40° C., and then after another hour slowly to 50-55° C. For
-blacks, the temperature is raised as high as 65° C. After dyeing the skins
-are treated with a solution containing per 10 liters
-
-  90-120 grams of olive-oil soap
-   12-25 grams olive oil
-      12 grams ammonia
-
-for 15 minutes, then hydro-extracted and dried, without further rinsing.
-
-For this method of dyeing, the following dyes may be used:
-
-For yellow and orange
-  Fast Yellow S
-  Acid Yellows
-  Naphthol Yellow S
-  Tropaeoline
-  Orange GG, R, II, IV
-
-For reds
-  Acid Reds
-  Lanafuchsine
-  Azo Orseille
-
-For violet
-  Azo Wool Violet
-  Acid Violets
-
-For blue
-  Cyanole FF
-  Azo Wool Blue
-  Naphthol Blue R
-  Formyl Blue B
-
-For green
-  Naphthol Green B
-  Fast Acid Green
-  Cyanole Green
-
-For brown, combinations of
-  Fast Yellow S
-  Acid Yellows
-  Tropaeoline DD
-  Orange GG
-  Lanafuchsine
-  Indigo Blue N
-  Cyanole B
-  Fast Acid Green BN
-
-For black
-  Naphthylamine Blacks
-  Naphthol Blacks
-  Naphthol Blue-black
-
-For grey
-  Silver Grey N
-  Dyed with the addition of 1/2-1% of alum
-
-The chrome colors are dyed on furs when very fast shades are desired, all
-the fancy colors being produced in this manner, but for black, only the
-acid dyes are suitable. The preparation of the skin is exactly the same as
-for the acid colors, except that the treatment with chloride of lime may
-be omitted, although for very full shades it is desirable. The dyeing is
-carried out as follows: The dyebath is prepared with the requisite amount
-of the desired dyestuff, which is previously dissolved, and to this is
-added a solution of sodium bichromate, the amount of this substance being
-half the weight of the dye. The solution is heated and the skins entered
-and dyed for 1-2 hours at 70-80° C. Then the dyebath is exhausted by the
-addition of 1/3% acetic acid, the skins being worked for another half
-hour, then rinsed, hydro-extracted and dried. Any of the one-bath chrome,
-or after-chrome colors may be used for this method.
-
-Recently methods have been patented for the dyeing of furs by means of
-the vat colors. Vat dyes are among the fastest coloring matters ever
-produced, and their application on furs would be a great advantage, if
-suitable shades could be obtained. The general process for dyeing with vat
-colors, consists in reducing the dye, which is usually very insoluble,
-into a soluble "leuco" compound, by means of hydrosulphites in the
-presence of alkalies. The leuco compound is not a dye itself, but when
-the fibre absorbs it, and is then exposed to the air, the leuco compound
-is reoxidized to its original insoluble form, which remains fast and
-permanent. The use of strong alkalies in vat dyeing has hitherto been a
-great obstacle in the use of these dyestuffs, but in 1917, the Farbwerke
-Hoechst, a large German dye works, patented a process as follows: "A
-process for dyeing furs with vat colors. The dyeing is done in solutions
-of the vat dyes (after the addition of gelatine or some other protective
-colloid), which are rendered neutral or only slightly alkaline with
-ammonia, by neutralizing the caustic soda of the solution of the leuco
-compound of the vat dyes by the addition of ammonium salts, or suitable
-acids. The dyeings thus obtained are uniform and fast, the leather is dyed
-to only a slight degree, and shows no deleterious effects of the dyebath
-on the tannage." As a practical application of this process, another
-patent was taken out by the same company, also in 1917, as follows:
-"A process for producing fast blacks on furs, consisting of dyeing a
-ground color with appropriate vat dyes in a hydrosulphite vat, and after
-oxidation in air, topping with an Aniline or Diphenyl black. The dyeings
-obtained by the combination of vat dyes which are fast to oxidizing
-agents, with an oxidation black, have an appearance matching that of
-logwood black in beauty; and with a dark-blue to blue-black under-color,
-and a full, deep black top color, cannot be distinguished from logwood.
-These dyeings also have the advantage of being faster to light than
-logwood or other blacks."
-
-While these processes undoubtedly have many meritorious qualities which
-make them interesting, they do not seem as yet, to have attained any
-great practical application. However, it is a field of fur dyeing which is
-worth while developing, and with certain necessary improvements in these
-processes, the vat dyes may yet supersede partially some of the other
-methods of dyeing furs.
-
-
-
-
-CHAPTER XVII
-
-BLEACHING OF FURS
-
-
-Bleaching is for the purpose of lightening the color of furs, and is
-most generally applied to white-haired skins such as white fox, ermine,
-and occasionally white lambs of all kinds, and white bears. Among such
-furs, pelts of a naturally pure white tone are relatively scarce, while
-in the majority of cases the color ranges from a pale creamy white to a
-decidedly yellowish shade. Colors which vary from the pure white detract
-considerably from the attractiveness and consequent value of the fur, and
-indeed, some pelts are so far off shade that they can only be used when
-dyed a darker color. Most white skins which are but slightly inferior in
-color can be brought to a pure white by bleaching, and they can then be
-used natural. Some pelts, on the other hand, are particularly resistant
-to the action of bleaching agents and cannot be sufficiently decolorized
-to render them suitable for use natural, so these are also dyed. For the
-production of certain delicate or fancy dyed shades on white furs, it is
-often necessary to bleach the skins in order to be able to obtain pure
-tones. Such instances are not very common, however. Occasionally dark
-furs, such as beaver, are bleached on the tips of the hair, a golden shade
-being obtained thereby, which at one time was quite popular, but recently
-such effects have not been in vogue.
-
-In the bleaching of furs, two steps may be distinguished, first
-degreasing, and second, bleaching proper. In the preliminary operations
-of fur dressing, the furs are treated with soap or weak alkalies to
-cleanse them and to remove excess oil from the hair. During the various
-processes and manipulations, the hair, especially on white skins, may
-become soiled or somewhat greasy again, so it is advisable to repeat
-the cleaning process. This should in every case be as light as possible,
-using a weak solution of soap for the softer and cleaner pelts, or dilute
-solutions of ammonium carbonate or soda ash for the more greasy-haired
-skins. The skins are then thoroughly rinsed to remove all traces of
-the degreasing material. This step is very essential in order to obtain
-uniform bleaching.
-
-Broadly speaking, there are two general methods which can be used in
-bleaching furs, one involving the use of what are known as reducing
-agents, and the other employing oxidizing substances.
-
-Among reducing agents which can be used for bleaching furs are sulphurous
-acid, and its salts such as sodium bisulphite and sodium sulphite;
-hydrosulphites, and derivatives.
-
-1. ~Sulphurous acid.~--When sulphur is burned, sulphur dioxide gas
-is formed. In the presence of moisture, or when dissolved in water,
-this gas forms sulphurous acid, which is one of the most commonly used
-bleaching chemicals for all sorts of materials, and is very effective
-for decolorizing furs. The procedure usually followed is to hang up the
-moistened skins on wooden rods in a more or less cubical chamber made of
-stone or brick, and lined with wood or lead. No other metals may be used,
-because they are quickly corroded by the sulphurous acid. The requisite
-quantity of sulphur is placed in a pot in the bleaching chamber, and then
-ignited, after which the doors are shut tight. The fumes of the burning
-sulphur in contact with the moist hair readily exert their bleaching
-action on the furs, and the operation is allowed to proceed for six or
-eight hours, or overnight. Then by means of fans or other devices, the
-air filled with sulphur dioxide gas is withdrawn from the chamber, and
-replaced by fresh air. The door is opened, the skins removed, exposed to
-the air for a time, then rinsed, and finally dried and finished. Sometimes
-one operation is not enough to sufficiently bleach the hair, so the
-process is repeated. Sulphur dioxide gas can now be obtained compressed
-in cylinders, which are more convenient to handle than burning sulphur.
-The flow of gas which is introduced into the bleaching chamber by means
-of a nozzle attached to the cylinder, can be regulated, and the bleaching
-thus retarded or accelerated.
-
-2. ~Sodium bisulphite and sodium sulphite.~--These salts of sulphurous
-acid are effective in their bleaching action only when in solution in the
-presence of acids. The acids liberate sulphurous acid from the salts,
-so this method is virtually the same as 1. Instead of using the salts
-of sulphurous acid, sulphur dioxide may be dissolved in water, and the
-solution used for bleaching by immersing the furs in it. This procedure,
-while consuming somewhat less time than the chamber process, is more
-likely to affect the leather, which would have to be retanned. The
-principle is the same as that involved in method 1.
-
-3. ~Hydrosulphites and derivatives.~--The bleaching agent can be prepared
-by adding zinc dust to commercial bisulphite of soda dissolved in about
-four times its weight of water until no more reaction is evident. Milk
-of lime is then added to precipitate the zinc, and the clear supernatant
-liquid of 1.5°-5° Tw. is used for bleaching. The skins are immersed
-for 12-24 hours, taken out, washed and finished. Instead of preparing
-the hydrosulphite, the commercial products may be used with greater
-convenience, a solution containing 1-4% of the hydrosulphite powder being
-used, and the skins treated in this until satisfactorily bleached.
-
-The bleaching action of sulphurous acid and hydrosulphite is supposed to
-be due to the reduction of the coloring matter of the hair to a colorless
-compound; or possibly to the formation of a colorless compound of the
-bleaching material with the pigment. The former seems the more probable
-explanation, because the change is not a permanent one, the original
-natural color returning after a long exposure of the bleached fur to air
-and light. However, the results are sufficiently enduring to satisfy the
-requirements of the trade in the class of furs on which these methods of
-bleaching are used.
-
-Bleaching chemicals with an oxidizing action generally used for
-decolorizing furs are hydrogen peroxide and peroxides; occasionally
-hypochlorites and permanganates are also used.
-
-1. ~Hydrogen peroxide.~--Hydrogen peroxide is usually employed for
-bleaching in the form of its 3% solution, to which is added about 20
-cubic centimeters of ammonia per liter. The ammonia serves partially to
-neutralize the acid which commercial peroxide generally contains, and
-also to facilitate the bleaching action. The thoroughly degreased skins
-are immersed in the solution until the hair is completely wetted by it,
-are then removed, and evenly pressed or hydro-extracted, after which
-the pelts are hung up to dry in the air. As the hair becomes drier,
-the concentration of the peroxide becomes greater, and consequently the
-bleaching action is stronger. Where there is a likelihood of the leather
-being affected by the bleaching solution, the ammoniacal peroxide may
-be applied to the hair with a fine sponge or brush until sufficiently
-wetted, and then hanging the skins up to dry. Repetition of the process
-is sometimes necessary to obtain pure white, but the results are always
-excellent.
-
-2. ~Peroxides.~--The most important of these is sodium peroxide, which
-comes on the market as a yellowish-white powder, which must be kept dry,
-and away from any inflammable material, as fires have been caused by the
-contact of the peroxide with such substances. When dissolved in water, it
-is equivalent to a strongly alkaline solution of peroxide of hydrogen.
-
-  Na{2}O{2} + 2H{2}O = H{2}O{2} + 2NaOH
-   sodium      water   peroxide   caustic
-  peroxide                of       soda
-                       hydrogen
-
-When dissolved in acid, the alkali is neutralized, and a neutral solution
-of peroxide of hydrogen and a salt is obtained, and this method is used
-to obtain peroxide of hydrogen cheaply.
-
-  Na{2}O{2} + H{2}SO{4} = H{2}O{2} + Na{2}SO{4}
-              sulfuric                 sodium
-                acid                  sulphate
-
-3 parts of sodium peroxide are slowly dissolved in a cold 1% solution of
-4 parts of sulphuric acid, stirring during the addition, and making the
-resulting solution neutral to litmus paper, acid or more sodium peroxide
-being added as needed. There is then added 3-6 parts of a solution
-of silicate of soda of 90° Tw. The skins are immersed until properly
-bleached, taken out, passed through a weak acid solution, then washed
-and finished. This method generally requires the leather to be retanned
-after bleaching. Another process, which involves the use of peroxides,
-but which is not commonly practised, consists in rubbing the hair with
-a pasty mixture of equal parts of water, barium dioxide, and silicate of
-soda, hanging up the skins to dry, and then beating and brushing the hair.
-
-3. ~Permanganates.~--The only member of this group that finds practical
-application for bleaching purposes is potassium permanganate. The skins
-are immersed in a 0.1% solution of the crystals of potassium permanganate,
-until the hair acquires a deep brown color. They are then removed, rinsed,
-and entered into a second bath containing sulphurous acid in solution,
-prepared by acidifying a solution of sodium bisulphite. The skins are then
-worked in this until fully bleached. It is the permanganate which does
-the bleaching, the sulphurous acid being for the purpose of dissolving
-the brown compound of manganese formed on the hair.
-
-4. ~Hypochlorites.~--Chloride of lime and sodium hypochlorite, which is
-prepared from the former, are the chief chemicals of this type used for
-bleaching. The skins are entered into a weak solution of the hypochlorite,
-and left until the hair is decolorized; then after removing, they are
-passed through a dilute acid, and subsequently through a weak solution of
-sodium thiosulphate in order to remove all traces of the hypochlorite.
-This method causes the hair to acquire a harsh feel, and the yellow
-color is never entirely eliminated. The hair, however, possesses a
-great affinity for certain types of dyestuffs, and it is only when
-these particular classes of dyes are to be applied to the furs, that the
-hypochlorite bleach is used. (See dyeing with Acid colors).
-
-The various oxidation methods of bleaching are supposed to change the
-coloring matter of the hair into an entirely different and colorless
-compound which cannot return to its original form. The bleach is therefore
-permanent.
-
-In common practise, the sulphurous acid, and the peroxide of hydrogen
-methods are the two chiefly employed in bleaching processes. Sulphurous
-acid is used to bleach the cheaper kinds of furs, while peroxide of
-hydrogen is applied to the finer furs.
-
-Whichever process is used, it is customary to give the bleached skins a
-subsequent "blueing," by passing them through a very weak solution of a
-blue or violet dye, such as indigo-carmine, crystal violet, alkali blue
-or ultramarine. The furs are then dried and finished off as usual. In drum
-cleaning white furs, gypsum or white sand, or sometimes even talc are used
-with the sawdust, or occasionally alone without the sawdust.
-
-
-
-
-BIBLIOGRAPHY
-
-
-  Allen "Commercial Organic Analysis"
-
-  Armour, B. R. "Fur Dressing and Dyeing" 1919
-
-  ---- Color Trade Journal, Vol. 1, p. 51-53
-
-  ---- Jour. Amer. Leather Chemists' Assn., Vol. 13, p. 63-69.
-
-  Belden, A. L. "Fur Trade in America" 1917
-
-  Beltzer, F. J. G. "Industrie des Poils et Fourrures, etc." 1912
-
-  ---- Revue Generale des Matieres Colorantes, Vol. 12, 1908
-
-  Bennett, H. G. "Manufacture of Leather" 1910
-
-  Bertram, P. Deutsche Färber-Zeitung 1895-96 Heft 17, p. 266
-
-  Bird, F. J. "American Practical Dyers' Companion" p. 241-245
-
-  Boerner, H. Kunststoffe, 1912 p. 223
-
-  Brevoort, H. L. "Fur Fibres as shown in the Microscope" 1886
-
-  Bucher, B. "Geschichte der technischen Künste" 1875-1893
-
-  Cubaeus, P. "Das Ganze der Kürschnerei" 1912
-
-  Davis, C. T. "Manufacture of Leather"
-
-  Erdmann, E. Deutsche Färber-Zeitung 1894-95 Heft 21, p. 337
-
-  ---- Zeitschrift für angewandte Chemie, 1895, Heft 14
-
-  ---- Zeitschrift für angewandte Chemie, Heft 35, 1905
-
-  ---- Berichte, 1904, 37, p. 2776, 2906
-
-  Farrell, F. J. "Dyeing and Cleaning" 1912
-
-  Fleming, L. "Practical Tanning" 1916
-
-  Fougerat, L. "La Pelleterie dans l'antiquité, la préhistoire, etc."
-
-  Gardner, W. M. "Wool Dyeing" 1896
-
-  Grandmougin, E. Zeitschrift für Farben-Industrie, 1906, 5, p. 141
-
-  Gruene, E. Deutsche Färber-Zeitung, 1895-96 Heft 13, p. 197
-
-  Halle "Werkstätte der heutigen Künste," 1762, Vol. 2, p. 317
-
-  Hartwig, O. L. "Sprengler's Künste und Handwerke," 1782
-
-  Hausman, L. A. Scientific Monthly, Jan. 1920; March, 1921
-
-  ---- Natural History, Vol. 20, 4, 1920
-
-  ---- American Journal of Anatomy, Sept. 1920
-
-  ---- American Naturalist, Nov.-Dec. 1920
-
-  Hayes, A. H. National Cleaner and Dyer, Nov. 1920, p. 55-57
-
-  Jacobson, "Schauplatz der Zeugmanufacturen" p. 493
-
-  Jones, J. W. "Fur Farming in Canada" 1913
-
-  Knecht, Rawson & Loewenthal "Manual of Dyeing" 1916
-
-  Kobert, R. "Beitrage zur Geschichte des Gerbens und der
-      Adstringentien" 1917
-
-  Koenig, F. Zeitschrift für angewandte Chemie, 1914, Vol. 1, p. 529
-
-  Lamb, J. W. Jour. Soc. Dyers & Colourists Dec. 1905, p. 323
-
-  Lamb, M. C. "Dressing of Leather" 1908
-
-  ---- Jour. Soc. Dyers & Colourists 1913, 29, p. 160-165
-
-  Larish & Schmid "Das Kuerschner Handwerk" 1-3
-
-  Laut, A. C. "The Fur Trade of America" 1921
-
-  Lightfoot, J. "The Chemical History & Progress of Aniline Black"
-      1871
-
-  Mairet, E. M. "A Book on Vegetable Dyes" 1916
-
-  Martin, G. "Industrial Organic Chemistry"
-
-  Matthews, J. M. "Application of Dyestuffs" 1920
-
-  Mayer, A. "Die Färberei in der Werkstätte des Kürschners"
-
-  Mierzinski, S. "Die Gerb und Farbstoffextrakte"
-
-  Noelting & Lehne "Anilin-Schwarz" 1904
-
-  Perkins & Everest "Natural Organic Coloring Matters" 1918
-
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-
-  Poland, H. "Fur-Bearing Animals in Nature and Commerce"
-
-  Proctor, H. "Leather Industries Laboratory Book"
-
-  ---- "Tanning"
-
-  ---- "Making of Leather"
-
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-
-  ---- Deutscher Färber-Kalender 1911, p. 65
-
-  ---- Leipziger Färber-Zeitung 1909, p. 441
-
-  Schmidt, C. H. "Handbuch der Weissgerberei"
-
-  Setlik, B. Deutsche Färber-Zeitung 1901, p. 213
-
-  Smith, R. W. Color Trade Journal Vol. 3, Sept. 1918, p. 304-310
-
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-
-  ---- Revue Generale des Matieres Colorantes, Vol. 23, p. 32-36
-
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-      No. 537
-
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-
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-
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-
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-      1900
-
-  Werner, H. "Die Kürschnerkunst" 1914
-
-  ---- "Das Färben der Rauchwaren" 1914
-
-  Whittaker, C. M. "Dyeing with Coal Tar Dyes" 1919
-
-  Wiener, F. "Weissgerberei" 1877
-
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-
-
-
-
-INDEX
-
-
-  Acetate, aluminum, 118
-
-  ---- chromium, 120
-
-  ---- copper, 120
-
-  ---- ferrous, 119
-
-  ---- lead, 126
-
-  Acetic acid, 112
-
-  Acid dyes, 174
-
-  Acids, action of, on hair, 29
-
-  ---- ---- on skin, 26
-
-  After-treatment with copper, 168
-
-  Alaska fox imitations, 143
-
-  Alkaline aluminum mordants, 122
-
-  ---- chromium mordants, 123
-
-  ---- iron mordants, 123
-
-  Alum, 32, 53, 118
-
-  ---- chrome, 57
-
-  ---- -chrome tans, 64
-
-  ---- tans, 54, 56
-
-  Aluminum acetate, 118
-
-  ---- mordants, 118
-
-  ---- sulphate, 53, 118
-
-  Ammonia, 110
-
-  Ammonium sulphide, 126
-
-  Aniline black, 144
-
-  ---- ---- by dip process, 154
-
-  ---- ---- chemistry, 145
-
-  ---- ---- Green's process for, 152
-
-  ---- ---- nature of, 144
-
-  ---- ---- One-bath, 149
-
-  ---- ---- Oxidation, 150
-
-  ---- ---- processes, 149
-
-  ---- ---- ungreenable, 148
-
-  Aniline oil, 145
-
-  Astrachan 5, 7, 12
-
-
-  Bacteria, 51
-
-  Badger, 7
-
-  Ball-drum, 62
-
-  Bandrowski's base, 164
-
-  Basic dyes, 171
-
-  Beam, 38
-
-  Beaming, 38
-
-  Bear, black, 5, 7
-
-  ---- brown, 5, 8
-
-  ---- white, 8
-
-  ---- ---- bleaching of, 179
-
-  Beating furs, 79
-
-  Beaver, 5, 8, 25, 83, 94
-
-  Beechwood ashes, 108
-
-  Bichromate of soda, 121, 147
-
-  Black, aniline, 144
-
-  ---- ---- by Green's process, 152
-
-  ---- ---- chemistry of, 145
-
-  ---- ---- nature of, 144
-
-  ---- ---- One-bath, 149
-
-  ---- ---- Oxidation, 150
-
-  ---- ---- ungreenable, 148
-
-  Black, diphenyl, 152
-
-  ---- logwood, 139
-
-  ---- on Chinese goats, 141
-
-  ---- on lambs, 141
-
-  ---- on raccoon, 130
-
-  ---- on skunk, 130
-
-  ---- on wolf, 130
-
-  Bleaching of furs, 179
-
-  Blending, 91, 104
-
-  Blue-grey on white furs, 142
-
-  Blueing, 184
-
-  Blue salt, 120
-
-  ---- vitriol, 119
-
-  Borax, 39, 58
-
-  Brasilein, 135
-
-  Brasilin, 135
-
-  Brazilwood, 135
-
-  Bright shades on furs, 171
-
-  Broadtail, 8, 12
-
-  ---- dyeing of, 139
-
-  Brown on Thibet sheep, 169
-
-  ---- with natural dyes, 142
-
-  Brush process, 98
-
-  Brushes used in dyeing, 100
-
-  Butter, 60, 63
-
-
-  Cage, 80
-
-  Cageing, 80
-
-  Campeachy wood, 133
-
-  Caracul, 8, 12
-
-  ---- dressing of, 53
-
-  Caracul, dyeing of, 140
-
-  Carnivorous animals, furs of, 37
-
-  Cased skins, 36
-
-  Castor oil, 60, 63
-
-  Cat, civet, 5, 8
-
-  ---- house, 8
-
-  Caustic soda, 44, 110, 113
-
-  Centrifugal machine, 40
-
-  Chamber drying, 73
-
-  Chamois dressing, 31
-
-  ---- tan, 49, 58, 61
-
-  Characteristics of tans, 65
-
-  Chestnut extract, 133
-
-  Chinchilla, 5, 6, 8, 94
-
-  ---- blending of, 91, 104
-
-  Chinchillone, 9
-
-  China goat, black on, 141
-
-  Chlorates, 147
-
-  Chloride of lime, 174
-
-  ---- ---- bleach, 184
-
-  Chrome acetate, 120
-
-  ---- alum, 57, 120
-
-  ---- colors, 176
-
-  ---- -copper mordant, 167
-
-  ---- -formaldehyde tan, 64
-
-  ---- tans, 57, 174
-
-  Chromium mordants, 120, 166
-
-  ---- ---- alkaline, 123
-
-  ---- salts in tanning, 53
-
-  Cleaning pelts, 40
-
-  Coal tar colors, 171
-
-  Cocoanut oil, 60
-
-  Cod-liver oil, 60
-
-  Collagen, 25
-
-  Colloidal solutions, 48
-
-  Combination tans, 49, 64
-
-  Conveying dyed skins, 104
-
-  Conveyor drying, 73
-
-  Copper acetate, 119
-
-  ---- mordants, 119, 166
-
-  ---- salts, 109
-
-  ---- ---- after-treatment with, 168
-
-  ---- sulphate, 119
-
-  Copperas, 119
-
-  Copper-iron mordant, 167
-
-  Coriin, 21
-
-  Corium, 21
-
-  Cortex, 23
-
-  Cottonseed oil, 60, 63
-
-  Cuba wood, 134
-
-  Cutch, gambier, 65, 135
-
-  Cuticle, 23
-
-
-  Davy, Sir Humphrey, 47
-
-  Degreasing furs, 179
-
-  Diphenyl black, 152
-
-  Dip process, 98
-
-  Dressing of lambs, 52
-
-  ---- ---- rabbits, 54
-
-  ---- ---- moles, 54
-
-  Drum, 80
-
-  Drum-cleaning, 105
-
-  Drumming, 76
-
-  Drying-oils, 60
-
-  Drying skins, 71
-
-  Durability of furs, 5
-
-  Dyeing furs at higher temperatures, 174
-
-  Dyeing of imitations, 93
-
-  ---- ---- novelty shades, 92
-
-  ---- with aniline black, 144
-
-  ---- ---- coal tar colors, 171
-
-  ---- ---- mineral colors, 125
-
-  ---- ---- oxidation colors, 155
-
-  ---- ---- vegetable colors, 128
-
-
-  Egg-yolk, 63
-
-  Emeraldine, 145
-
-  Enzymes, 51
-
-  Epidermis, 21
-
-  Erdmann, 155
-
-  Ermine, 5, 9
-
-  ---- bleaching of, 179
-
-
-  Fahrion, 48
-
-  Fat-glands, 21
-
-  Fats, animal, 59
-
-  Fermentation, 51
-
-  Ferrous acetate, 119
-
-  Ferrous sulphate, 119
-
-  Finishing dyed furs, 104
-
-  Fisher, 9
-
-  Fitch, 9, 94
-
-  Flat skins, 36
-
-  Fleshing, 41
-
-  ---- knife, 38, 42
-
-  ---- machines, 42
-
-  Flesh side, 22, 37
-
-  Formaldehyde, 63
-
-  ---- -chrome tan, 64
-
-  ---- tans, 49, 63
-
-  Formic acid, 44, 50
-
-  ---- ---- as soaking agent, 39
-
-  Fox, black on, 140
-
-  ---- blue, 9
-
-  ---- cross, 4, 10
-
-  ---- grey, 10
-
-  ---- kit, 10
-
-  ---- red, 4, 5, 10
-
-  ---- ---- dyed imitation silver fox, 137
-
-  ---- silver, 4, 10
-
-  ---- ---- imitations, 137, 143
-
-  ---- white, 11, 94
-
-  ---- ---- bleaching of, 179
-
-  French seal dye, 138, 144
-
-  Furamine dyes, 162
-
-  Fur beating machine, 80
-
-  Fur dressing, 30
-
-  Fur dyeing, 91
-
-  ---- ---- difficulties of, 95
-
-  ---- ---- with aniline black, 144
-
-  ---- ---- with coal tar colors, 171
-
-  ---- ---- with mineral colors, 125
-
-  ---- ---- with oxidation colors, 155
-
-  ---- ---- with vegetable colors, 128
-
-  Fur-hair, 24
-
-  Furriers' guilds, 34, 90
-
-  Furrol dyes, 166
-
-  Furs, colors of, 3
-
-  ---- description of, 7
-
-  ---- durability of, 5
-
-  ---- of carnivorous animals, 37
-
-  ---- of herbivorous animals, 37
-
-  ---- quality of, 3, 4
-
-  ---- uses of, 1
-
-  ---- valuation of, 6
-
-  ---- weight of, 5
-
-  Fustic, 134
-
-  ---- shades with, 135
-
-
-  Gall-nuts, 128, 132
-
-  Gambier cutch, 65, 135
-
-  Gelatine, 1, 25, 47, 48
-
-  Genet, 5
-
-  Glycerine, 63
-
-  Goat, 5, 11
-
-  ---- logwood black on, 141
-
-  Green's process for aniline black, 152
-
-  Grey-blue on white furs, 142
-
-  Ground water, 87
-
-  Guard-hair, 24
-
-  Guilds, furriers', 34, 90
-
-
-  Hair, 22
-
-  ---- action of acids on, 27
-
-  ---- action of alkalies on, 28
-
-  ---- action of salts on, 28
-
-  Hamster, 3, 11
-
-  Hardness of water, 87
-
-  Hare, 5, 11, 94
-
-  ---- black on, 140
-
-  ---- blue-grey on, 142
-
-  ---- lynx dye on, 126
-
-  ---- stone marten imitation on, 126
-
-  Hematein, 133
-
-  Hematoxylin, 133
-
-  Herbivorous animals, furs of, 37
-
-  Hudson seal, 144
-
-  Hydro-extraction, 40
-
-  Hydrogen peroxide, 168
-
-  ---- ---- bleaching with, 182
-
-  Hydrosulphite bleach, 181
-
-  Hypochlorites, 184
-
-
-  Imitations, dyeing of, 93
-
-  Iron mordants, 119, 167
-
-  Iron pyrolignite, 119
-
-  Iron salts in tanning, 53
-
-  Iron tan, 58
-
-  Iron vitriol, 119
-
-
-  Kangaroo, 12
-
-  Keratin, 25
-
-  Kicker, 61
-
-  Killing, 98, 106
-
-  ---- formulas, 108
-
-  ---- nature of, 107
-
-  ---- purpose of, 106
-
-  ---- by brush process, 111
-
-  ---- by dip process, 111
-
-  ---- with caustic soda, 113
-
-  ---- with lime, 112
-
-  ---- with soda, 112
-
-  Knapp, 46, 57
-
-  Knife, beaming, 38
-
-  ---- shaving, 38
-
-  ---- fleshing, 38
-
-  Kolinsky, 5, 12
-
-  Krimmer, 5, 12, 13
-
-
-  Lactic acid, 44, 51
-
-  Lactic acid fermentation, 50
-
-  Lambs, 12
-
-  ---- dressing of, 50, 53
-
-  ---- dyeing of, 92, 140, 141, 142
-
-  Lard, 60
-
-  Lead, acetate, 126
-
-  Lead sulphide dye, 126
-
-  Leather, definition of, 48
-
-  ---- dressing of, 30
-
-  Leopard, 5, 13, 94
-
-  ---- tanning of, 43
-
-  Lima wood, 135
-
-  Lime, 108, 110, 112
-
-  Linseed oil, 60
-
-  Litharge, 109
-
-  Loft drying, 72
-
-  Logwood, 133
-
-  ---- blacks, 139
-
-  ---- shades with, 134
-
-  Lynx, 5, 13
-
-  ---- imitation on rabbit and hare, 126
-
-  Luster of hair, 23
-
-
-  Machines used in brush dyeing, 102
-
-  ---- ---- dip dyeing, 103
-
-  Marmot, 14, 68, 94
-
-  Marten, blending of, 91, 104
-
-  Marten, baum, 5, 14
-
-  ---- stone, 5, 14
-
-  ---- ---- imitation, 126
-
-  Medulla, 22
-
-  Meunier, 46
-
-  Mineral colors, 125
-
-  ---- oils, 59, 63
-
-  ---- tans, 49, 53
-
-  Mink, 5, 14, 68, 94
-
-  Mole, 5, 15
-
-  ---- tanning of, 54
-
-  Monkey, 15
-
-  Mordanting, 98, 114
-
-  Mordants, alkaline, 121
-
-  ---- aluminum, 118
-
-  ---- chrome-copper, 167
-
-  ---- chromium, 120, 166
-
-  ---- copper, 119, 166
-
-  ---- copper-iron, 167
-
-  ---- iron, 119, 167
-
-  ---- tin, 121
-
-  Mucines, 25
-
-  Muskrat, 5, 15, 68, 94
-
-  ---- imitation seal on, 144, 169
-
-
-  Neats-foot oil, 60, 63
-
-  Neradol D., 64
-
-  Nigraniline, 147
-
-  Non-drying oils, 60, 63
-
-  Novelty shades, dyeing of, 92
-
-  Nutgalls, 33, 132
-
-  Nutria, 5, 15, 94
-
-
-  Oiling, 62, 77
-
-  Oils, drying, 60
-
-  ---- non-drying, 50
-
-  ---- partially-drying, 60, 63
-
-  Olive oil, 60
-
-  One-bath aniline black, 149
-
-  Opossum, 5, 15, 68
-
-  ---- black on, 140
-
-  ---- skunk imitation on, 138
-
-  ---- seal imitation on, 144
-
-  Otter, River, 5, 16, 94
-
-  ---- Sea, 5, 16
-
-  Over-hair, 24
-
-  Oxidation aniline black, 150
-
-  ---- colors, 155
-
-  ---- ---- shades with, 165
-
-
-  Para-amido phenol, 153, 157
-
-  Para-phenylene diamine, 153, 157, 162
-
-  Partially-drying oils, 60, 63
-
-  Pelage, 2
-
-  Pelt, 2
-
-  Pernambuco wood, 135
-
-  Peroxide of hydrogen, 168, 182
-
-  Peroxides, 182
-
-  Persian lamb, 5, 12
-
-  ---- ---- dressing of, 50, 53
-
-  ---- ---- dyeing of, 139
-
-  Physical theories of tanning, 47
-
-  Pickle, 49
-
-  Pigment granules, 23
-
-  Pony, Russian, 5, 16
-
-  Potassium permanganate as a dye, 127
-
-  ---- ---- as a bleach, 183
-
-  Protective-hair, 24
-
-  Pyrolignite of iron, 119
-
-
-  Quercitron, 135
-
-  Quinone di-imine, 163
-
-
-  Rabbit, 6, 17, 94
-
-  ---- imitation seal on, 144
-
-  ---- lynx imitation on, 126
-
-  ---- sable imitation on, 168
-
-  ---- stone marten imitation on, 126
-
-  ---- tanning of, 54, 65
-
-  Raccoon, 6, 17
-
-  ---- black on, 140
-
-  ---- skunk imitation on, 170
-
-  Rain water, 86
-
-  Red fox, dyed as silver fox, 137
-
-  Redwood, 135
-
-  Rodol colors, 165
-
-  Russian tan, 51
-
-
-  Sable, 6, 94
-
-  ---- American, 17
-
-  ---- blending of, 91, 104
-
-  ---- imitation on rabbit, 168
-
-  ---- Russian, 18
-
-  Salammoniac, 109
-
-  Salt, 32, 49
-
-  ---- -acid tan, 49
-
-  ---- -water soak, 39
-
-  Salts, neutral, 54
-
-  ---- basic, 54, 115
-
-  Sawdust in drum-cleaning, 80
-
-  "Schrot-beize," 50
-
-  Seal, 6, 18, 94
-
-  ---- fur, 18
-
-  ---- dyeing of, 92, 144
-
-  ---- hair, 19
-
-  ---- imitation on muskrat, 138, 169
-
-  ---- -oil, 60
-
-  Shearing, 82
-
-  ---- machine, 84
-
-  Shrinking-point of skins, 66
-
-  ---- effect of chemicals on, 67
-
-  Silver fox imitations, 137, 143
-
-  Skin, 21
-
-  ---- action of acids on, 26
-
-  ---- action of alkalies on, 27
-
-  Skunk, 6, 19, 94
-
-  ---- imitation on opossum, 138
-
-  ---- ---- on raccoon, 170
-
-  Soaking skins, 39
-
-  Soda ash, 110, 112
-
-  Sodium bichromate, 121, 166
-
-  ---- bisulphite, 127, 181
-
-  ---- chloride, 49
-
-  ---- peroxide, 182
-
-  ---- sulphite, 181
-
-  Soft water, 87
-
-  Softening skins, 38
-
-  Souring, 113
-
-  Squirrel, 6, 19
-
-  Staking, 78
-
-  Stannous chloride, 121
-
-  Stiasny, 64
-
-  Stone marten imitation, 126
-
-  Stretching, 78
-
-  ---- machines, 78
-
-  Sugar of lead, 126
-
-  Sulphonated oils, 63
-
-  Sulphuric acid, 49
-
-  Sulphurous acid bleach, 180
-
-  Sumach, 128, 133
-
-  ---- tanning with, 33
-
-  Surface water, 87
-
-  Sweat-glands, 22
-
-
-  Tallow, 60
-
-  Tanned furs, qualities of, 48
-
-  Tanning methods, comparison of, 65
-
-  Tannins, 32, 132
-
-  Tiger, 19
-
-  Top-hair, 24
-
-  Train oils, 63
-
-  Tramping machine, 61
-
-  Turmeric, 136
-
-
-  Under-hair, 24
-
-  Under-wool, 24
-
-  Ungreenable aniline black, 148
-
-  Unhairing, 82
-
-  ---- machine, 83
-
-  Ursol dyes, 157, 165
-
-
-  Vanadium compounds, 147
-
-  Vat dyes, 177
-
-  Vegetable dyes, 128, 136
-
-  ---- oils, 59
-
-  ---- tans, 49, 65
-
-  Verdigris, 120
-
-
-  Water, hard, 87
-
-  ---- soft, 87
-
-  Whale oil, 60
-
-  White fox, bleaching of, 179
-
-  Wolf, 6, 19
-
-  Wolverine, 6, 20
-
-  Wombat, 20
-
-  Wood dyes, 128
-
-
-  Yellow wood, 134
-
-
-
-
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-Transcriber's Notes:
-
-Punctuation has been standardised--in particular, missing periods
-and quotation marks have been supplied where obviously required.
-Three entries in the bibliography were located out of alphabetical
-order, and have been moved accordingly (Fougerat, Lamb, Martin).
-All other original errors and inconsistencies have been retained,
-except as follows:
-
-  Page 7:   changed Enclyclopedia to Encyclopedia
-            (in Encyclopedia Britannica, 11th Ed.)
-  Page 20:  changed Kaola to Koala
-            (Koala or Australian Bear.)
-  Page 62:  changed partiular to particular
-            (on the particular fur treatment)
-  Page 67:  changed degress to degrees
-            (almost 10 degrees higher than)
-  Page 73:  changed samewhat to somewhat
-            (based on a somewhat different)
-  Page 93:  changed imitatations to imitations
-            (dyeing of imitations to a great)
-  Page 101: changed diagramatically to diagrammatically
-            (and B shows diagrammatically, machines)
-  Page 128: changed conjuction to conjunction
-            (which in conjunction with certain)
-  Page 136: changed curcuma to Curcuma
-            (stem of the Curcuma tinctoria,)
-  Page 137: changed simutaneously to simultaneously
-            (and dye simultaneously; and third)
-  Page 140: changed atmopheric to atmospheric
-            (aid of the atmospheric oxygen.)
-  Page 142: changed followlowing to following
-            (successively in the following baths:)
-  Page 149: changed ozidizing to oxidizing
-            (is also an oxidizing agent and)
-  Page 154: changed dryig to drying
-            (several times, drying each time at)
-  Page 161: changed manufacurers to manufacturers
-            (Other manufacturers of coal-tar)
-  Page 170: changed Racoon to Raccoon
-            (_Imitation Skunk on Raccoon_)
-  Page 185: changed Werkstatte to Werkstätte
-            (Halle "Werkstätte der heutigen)
-  Page 185: changed Gerben to Gerbens
-            (Geschichte des Gerbens und der)
-  Page 185: changed Astringentien to Adstringentien
-            (und der Adstringentien" 1917)
-
-
-
-
-
-End of the Project Gutenberg EBook of Principles and Practice of Fur
-Dressing and Fur Dyeing, by William E. Austin
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-The Project Gutenberg EBook of Principles and Practice of Fur Dressing and
-Fur Dyeing, by William E. Austin
-
-This eBook is for the use of anyone anywhere at no cost and with
-almost no restrictions whatsoever.  You may copy it, give it away or
-re-use it under the terms of the Project Gutenberg License included
-with this eBook or online at www.gutenberg.org
-
-
-Title: Principles and Practice of Fur Dressing and Fur Dyeing
-
-Author: William E. Austin
-
-Release Date: January 28, 2013 [EBook #41938]
-
-Language: English
-
-Character set encoding: ASCII
-
-*** START OF THIS PROJECT GUTENBERG EBOOK FUR DRESSING, FUR DYEING ***
-
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-Produced by Chris Curnow, Rosanna Murphy and the Online
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-file was produced from images generously made available
-by The Internet Archive)
-
-
-
-
-
-Transcriber's Note: Italic text is denoted by _underscores_ and
-bold text by ~tildes~. Subscripted text is enclosed in {braces}.
-
-
-
-
-FUR DYEING AND FUR DRESSING
-
-
-
-
-                  PRINCIPLES AND PRACTICE
-                            OF
-                FUR DRESSING AND FUR DYEING
-
-
-                            BY
-                  WILLIAM E. AUSTIN, B.S.
-          CONSULTING CHEMIST TO THE FUR INDUSTRY
-
-
-                       _ILLUSTRATED_
-
-
-                      [Illustration]
-
-
-                         NEW YORK
-                  D. VAN NOSTRAND COMPANY
-                    EIGHT WARREN STREET
-                           1922
-
-
-                    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 dyeing 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 dressing and dyeing of furs.
-Even among members of other branches of the fur trade, there is very
-little accurate information on the subject. Real knowledge concerning fur
-dressing and dyeing is possessed only by those actually engaged 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 dressing 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. 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
-developments, 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 chemistry, since it will be an
-introduction into a field of applied chemistry, about which very little
-is known to those outside of the industry.
-
-Thanks are due to Dr. L. A. Hausman, of Cornell University, 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.
-
-
-
-
-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
-        relative 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
-        organizations 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
-        operations 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.
-
-
-    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 mordants.
-        Iron mordants. Copper mordants. Chromium mordants. 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
-        materials. The tannin substances. Logwood. Fustic.
-        Brazilwood. 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 Oxidation color. Range of shades obtainable.
-        Mordants. Procedure 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
-
-
-
-
-FUR DRESSING AND FUR 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 considered: 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 accessories, 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 subjected 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 operations 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 dresser
-and the fur dyer in addition to the technical knowledge and experience
-which are the fundamental requisites of the industry, also to have more
-than a superficial familiarity 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 almost
-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 considerably 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 called a pelt, or sometimes, in the case of large
-animals, a hide. The pelt, after having been dressed and dyed, is called
-a fur, the skin part being referred to as the leather, 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 increases 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 Siberian hare, are found only in the
-northern lands. An exception 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 known 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 correspondingly lower temperatures,
-have thicker and finer hair than those living nearer sea-level. A cold
-winter generally produces fur of high quality and fine color, a mild
-winter may 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. Animals 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 too tender to be fit for use. In certain
-cases, particularly the baby lambs, very young skins are especially
-prized, and 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 becomes 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 begins 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.
-
-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
-sections of the skin.
-
-Furs do not have differences confined to the hair part only; the leather
-also presents considerable variation among the different fur-bearing
-animals, especially in regard to the weight and thickness. The durability
-of furs, relatively considered under similar conditions of wear, also
-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 of Fur_             _Durability_    _Wt. in oz.
-                                     _Otter = 100_   per sq. ft._
-  Astrachan                                10           3
-  Bear, brown or black                     94           7
-  Beaver, natural                          90           4
-  Beaver, plucked                          85           3-7/8
-  Chinchilla                               15           1-1/2
-  Civet cat                                40           2-3/4
-  Coney                                    20           3
-  Ermine                                   25           1-1/4
-  Fox, natural                             40           3
-  Fox, dyed black                          25           3
-  Genet                                    35           2-3/4
-  Goat                                     15           4-1/8
-  Hare                                     05           2-1/4
-  Krimmer                                  60           3
-  Kolinsky                                 25           3
-  Leopard                                  75           4
-  Lynx                                     25           2-3/4
-  Marten, Baum natural                     65           2-3/4
-  Marten, Baum blended                     45           2-3/4
-  Marten, Stone natural                    45           2-7/8
-  Marten, Stone dyed                       35           2-7/8
-  Mink, natural                            70           3-1/4
-  Mink, dyed                               35           3-1/4
-  Mink, Jap                                20           3
-  Mole                                     07           1-3/4
-  Muskrat                                  45           3-1/4
-  Nutria, plucked                          25           3-1/4
-  Opossum, natural                         37           3
-  Opossum, dyed                            20           3
-  Opossum, Australian                      40           3-1/2
-  Otter, land                             100           4-1/2
-  Otter, sea                              100           4-1/2
-  Persian lamb                             65           3-1/4
-  Pony, Russian                            35           3-1/2
-  Rabbit                                   05           2-1/4
-  Raccoon, natural                         65           2-1/4
-  Raccoon, dyed                            50           2-1/2
-  Sable                                    60           2-1/2
-  Sable, blended                           45           2-1/2
-  Seal, fur                                80           3-1/2
-  Seal, fur dyed                           70           3-1/8
-  Skunk, tipped                            50           2-7/8
-  Squirrel, grey                           20-25        1-3/4
-  Wolf, natural                            50           6-1/2
-  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,
-condition 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, lightness 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 tend to decrease the number of
-available pelts of any particular animal, such as pestilences, gradual
-extermination due to excessive trapping, prevention of trapping, by
-protective 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 beautiful and rare, such as Russian
-sable or chinchilla, are practically 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 depreciate in value.
-
-A detailed description of the various furs used in commerce 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 dressing and dyeing of furs should have at least a passing
-acquaintance with the chief furs used in commerce, together with such of
-their individual characteristics as are of importance. The figures given
-are for the average dressed skin.[1]
-
-  [1] Descriptions after W. S. Parker, Deputy Chairman, Fur Section of
-      London Chamber of Commerce, in Encyclopedia Britannica, 11th Ed.
-
-~Astrachan~, see Lambs.
-
-~Badger.~--2 x 1 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 occasionally but is
-mostly used natural. Badger hair is very extensively used for 'pointing.'
-
-~Bear, Black.~--6 x 3 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 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 yellow 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 ft. 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 suitable furs are now used.
-
-~Broadtail~, see Lambs.
-
-~Caracul~, see Lambs.
-
-~Cat, Civet.~--9 x 4-1/2 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
-certain period. The fur is of a delicate blue-grey, with black shadings,
-the fur being 1 - 1-1/4 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 2-1/2 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 1/3 of an inch deep. The top-hair
-is black, 1-1/2 - 1-3/4 inches long, very fine and open in growth, and not
-so close as the martens. The largest and best skins are from Denmark,
-Holland 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 are more silky and of a smoky bluish color, and being scarce are
-most valuable. The white foxes 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 the
-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-hair, 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 soft, 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
-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 inhabits the extreme
-northern sections of Hudson Bay, Labrador, 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.~--8 x 3-1/2 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; occasionally 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
-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 being 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.~--12 x 2-1/2 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 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.~--3 x 6 feet long. There are several kinds, the chief being the
-snow leopard or ounce, Chinese, Bengal, Persian, East Indian, and African.
-The first variety inhabits the Himalayas, and has a deep, soft fur, quite
-long as compared 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 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 nature 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 Japanese sorts are so pale that they are
-always dyed.
-
-~Mole.~--3-1/2 x 2-1/2 inches. Is plentiful in the British Isles and
-Europe, and is much in demand on account of its velvety 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
-under-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 is found in central sections of the United States, and is
-frequently 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, 7 x 4 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 beautiful 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-white
-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 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 Australia. The color ranges from white to black. France,
-Belgium 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 - 1-1/2 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 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 1-1/2 to 2-1/2 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, particularly 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 regions. The dressing and dyeing of seal takes longer
-than for 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 2-1/2 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 imported 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 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 nature of the bear. The under-hair is
-full and thick, with strong, bright top-hair about 2-1/2 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, Koala or Australian Bear.~--20 x 12 inches. It has a light grey
-or brown, close, thick under-hair 1/2 inch deep, and no top-hair, with a
-rather thick, spongy pelt. It is cheap, and well suited for rough wear.
-
-
-
-
-CHAPTER II
-
-STRUCTURE OF FUR
-
-
-Fur is made up of two main components, the hair and the skin, and each of
-these has a very complex structure.
-
-In the living animal the skin serves as a protective covering, and also
-constitutes an organ of secretion and of feeling; consequently it is
-of a highly complicated nature. The skin of all fur-bearing animals is
-essentially the same in structure, although varying considerably as to
-thickness and texture. It consists of two principal layers, which are
-entirely different in structure and purpose, and correspondingly different
-in both physical and chemical respects: the epidermis, epithelium or
-cuticle, which is the outer layer, and the dermis or corium, which is the
-true skin. (Fig. 1A).
-
-The epidermis is very thin as compared with the corium. Its outer layer
-consists of a tissue of cells, somewhat analogous to the horny matter
-of nails and hair. The inner surface, called the 'rete malpighi,' rests
-on the true skin, and 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. It 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 a somewhat different nature from the fibres, the coriin.
-Towards the center of the skin, the texture of the interweaving fibres
-is looser, becoming much more compact at the surface 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 surface next to the
-flesh is also closer in structure than the middle portions of the skin,
-and has somewhat of a membranous 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 the flesh 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 animal, 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,
-surrounds 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 structure as the
-skin, and is made up of four distinct parts. (Fig. 1B).[2]
-
-  [2] Descriptions and figures taken from "Mammal Fur Under the
-      Microscope," by Dr. L. A. Hausman, in _Natural History_,
-      Sept.-Oct., 1920.
-
-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.
-
-Surrounding the medulla is the cortex, which is made up of spindle-shaped
-cells fused into a horny, almost homogeneous, transparent mass, and
-forming a large proportion of the hair shaft.
-
-In the majority of the fur-bearing animals, there is distributed within
-and among the cells of the cortex a pigment in the form of granules or
-minute particles, arranged in the different hairs in fairly definite and
-characteristic patterns. It is to these pigment granules that the color
-of the hair is due primarily. In some cases the coloring matter of the
-shaft is uniformly diffused and not granular.
-
-[Illustration: FIG. 1
-
-_A._ STRUCTURE OF SKIN.
-
-_B._ STRUCTURE OF HAIR.]
-
-The outermost coat of the hair, or cuticle, is composed of thin,
-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. Since lustre 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
-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-section 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 protective 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, and varying so
-greatly in physical structure, both the skin and the hair belong to
-the same class of chemical compounds, 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 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 deg. C., they coagulate and are then
-insoluble. Concentrated mineral acids and strong alcohol will also effect
-coagulation.
-
-[Illustration: FIG. 2
-
-_A._ HAIR OF EUROPEAN BEAVER.
-
-_a._ TOP-HAIR. _b._ UNDER-HAIR.
-
-_B._ HAIR OF SKUNK.
-
-_a._ TOP-HAIR. _b._ UNDER-HAIR.]
-
-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 epidermis, and the walls of the cells of
-the inner layer of the 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, forming 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, vegetable
-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
-become stiff, horny and translucent. The mucines are also constituents of
-the cells of the 'rete malpighi.' The solubility 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 keratins of the hair and epidermis
-cells. On cooling, the solution solidifies to a jelly of gelatine. It
-combines with both acids and alkalies. A property of the skin which is
-of importance 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 solutions, the skins swell up less, while more of the skin
-substance dissolves, and by prolonged action of strong acids or alkalies,
-an almost complete solution of the skin is obtained, 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 increases
-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 epithelium 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 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 formation of ammonia and amino-acids.
-Ammonium 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. Calcium 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, are absorbed 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.
-
-
-
-
-CHAPTER III
-
-FUR DRESSING
-
-INTRODUCTORY AND HISTORICAL
-
-
-Fur dressing has a twofold purpose. First of 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
-decomposition. Having taken measures to assure the endurance or relative
-permanency of the pelt, the prime consideration 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 relatively unimportant, since
-it is not seen after the furs are made into garments. There 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 employment 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 appearance of the hair, and the leather is of
-secondary importance, in the production of leather, the hair plays no part
-at all, since it is entirely removed from the pelt. The fundamental points
-of resemblance between leather manufacture 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, ornament, 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 suitable 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." Numerous other biblical references indicate the use
-of animal skins for various purposes, sometimes prepared as leather,
-with the hair removed. Among the Egyptians tanning seems to have been
-a common 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-producing
-processes of the Egyptians are quite unknown, numerous figures engraved in
-stone afford an indication to 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 sarcophagi, 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 Assyrian, Phoenician
-and Persian origin, tends to show that these peoples also possessed a
-considerable degree of proficiency in tanning. Frequent references in the
-Greek literature 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
-excelled by any dressed with more modern processes and tanning methods.
-
-The next step forward in the preparation of animal skins 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 processes 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 vegetable 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 plants
-which possessed the highest content of active ingredients, 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 tanning, the methods
-probably differing in each country. Thus the Chinese, Syrians, and much
-later, the Moors, were each known 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 centered 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 supremacy, historical records
-show that the furriers, who did 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 beginning 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 association
-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 beginning of the
-nineteenth century, the guild system became ineffective, but the
-furriers continued their work as heretofore. 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 himself, 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 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.
-
-
-
-
-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 attached 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 overheat 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 the head off the body like a glove, trimming carefully about the
-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 without wrinkling. The pelts, after drying
-in a dry, airy place, are removed from the stretchers and are ready for
-the market. 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 operations 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 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 derived 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
-animal 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
-modified 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 and fatty tissues adhering to
-it, and the hair is generally soiled and occasionally blood-stained. In
-order to get the 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 deg. It is generally
-flat, although 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.
-
-[Illustration: FIG. 3. BEAM.]
-
-[Illustration: FIG. 4. KNIVES USED IN FUR DRESSING.]
-
-The first step in softening the skins is to get them thoroughly 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 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, continue as soon as the pelt is again moistened. The progress
-of decay causes the evolution of certain gases, the simplest of which
-is ammonia, 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 solution of 1/4% 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
-preservative 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
-soft and flexible. Sometimes 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 for several
-hours, or overnight. Another method which is practised with certain types
-of skins is the use of wet sawdust or of sawdust moistened with salt
-water. The fur skins are either embedded in the sawdust or drummed with
-it for several hours, or until sufficient moisture has been absorbed
-to render them flexible. By this means there is no danger of the skins
-being over-soaked, or of the hair being loosened. When the skins 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. Other 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 effective. The cleansed skins are then
-thoroughly rinsed to remove 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 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.
-The inner surface of the basket can also be enamelled or otherwise made
-resistant to the action of acids or other chemicals.
-
-[Illustration: FIG. 5. CENTRIFUGAL MACHINE.
-
-(_Fletcher Works, Inc., Philadelphia_)]
-
-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 expose the corium, enabling the efficient action of the chemicals
-used in the tanning processes. The process of removing this undesirable
-layer from the flesh-side is known as fleshing. 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. 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 are placed on the beam, and
-fleshed with a fleshing or skiving 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 suitable 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 regulating 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 difficulties, 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 occasionally met by the fur dresser,
-the skins after being soaked, 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 applied to the
-skins, thereby causing a swelling action to set 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.
-
-[Illustration: FIG. 6. FLESHING KNIFE ON BENCH.]
-
-[Illustration: FIG. 7. FLESHING MACHINE.
-
-(_Turner Tanning Machinery Co., Peabody, Mass._)]
-
-
-
-
-CHAPTER V
-
-FUR DRESSING
-
-TANNING METHODS
-
-
-After the pelts have gone through the preliminary operations of softening,
-washing and fleshing, they are ready to receive the treatment which
-will convert the easily decomposing skin into leather of 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 problem of leather formation.
-Numerous theories as to the nature 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. Procter, 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.... 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 substance 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 evaporated, left a thin fatty
-covering on the fibres which completely 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 matters, 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
-evaporates. 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 otherwise, but merely to isolate and coat them
-with water-resisting 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 insoluble and nonadhesive.
-
-"Before Knapp's work, the prevalent theory, at least as regards vegetable
-tannage, had been a chemical one, started 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 proportions of its constituents were
-considerably varied by changes in the strength of the solutions, or by
-washing the precipitate with hot water; and further, that in chemical
-compounds, 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 guncotton 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 substances,
-chemical reactions are rarely complete, but that stable positions are
-reached, so-called 'equilibria,' in which the proportion of changed and
-unchanged substance is dependent on concentration or other conditions;
-and that therefore such a precipitate might well be a mixture of gelatine
-with a true gelatine tannate from which further portions 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 substance. Nevertheless, these particles have many molecular
-properties, possessing plus or minus electrical charges; behaving like
-large ions under the influence of an electrical current; and mutually
-precipitating and neutralizing each other when positive and negative
-are brought together. Such solutions are called '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 '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 processes, 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 presence 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
-somewhat less rigorous standard of conditions to fulfil is satisfactory
-for the general needs and purposes of furs. The chief qualities which
-tanned furs must possess, with particular reference to the leather side of
-the pelt, are retention 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 operation 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 tanning 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 1/2 - 3/4 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 depending on the thickness of the skins. When the corium 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 skin
-may be considered 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 1/4%
-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 solution 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 turning the skins
-hair-side inward, they are laid flat together in pairs 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 particles
-adhering to the flesh-side. This operation is continued 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 manner: 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
-cannot 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 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
-bacteria attack solid substances from which they obtain their nourishment,
-but this is done in an indirect way, by secreting 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 property of bringing
-about the chemical change of an almost indefinite 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 chemical
-changes, particularly inducing fementations. 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 furfuris 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
-production of lactic acid. In both cases, the acids as they form swell
-and loosen up the skin fibres slowly, the salt penetrating 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 advantage 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 the grains of the tan, aside from their tanning action, contributing
-to the fullness and softness of the leather. There is also less likelihood
-of the leather being subsequently affected 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 considerably 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
-industry 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 endowed with the quality of converting skin
-to leather under suitable conditions, chromium and iron being the most
-important metals in this connection. Chemically these metals all belong
-to the same group, and have properties which are very similar in many
-respects, the characteristic 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 normal 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 of 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 absorb 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 thousand 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
-aluminum sulphate are the chief compounds used for this tan. In recent
-years, the aluminum sulphate has to a considerable 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 equivalent amount of free acid. The
-reaction may be shown as follows:
-
-  Al{2}(SO{4}){3} + 2H{2}O = Al{2}(SO{4}){2}(OH){2} + H{2}SO{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 by the skin, probably attaching itself to some of the acidic groups
-contained in the skin substance, in a manner analogous 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 and quite useless condition. If to the
-solution of the aluminum 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 quantity 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 lbs. of alum and 3 lbs. 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 lbs. of alum and 3 lbs. of salt, dissolved
-in 8 gallons of water, and made into a paste by the addition of 4 lbs. 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 application 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 time for it to be absorbed, another
-application is given, rubbing 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 drying. They
-are left so until tanned, as shown by examination and test. They are then
-rinsed, hydro-extracted and dried, and after stretching and finishing, a
-soft, white, pliable leather is obtained.
-
-
-B. _Chrome Tan_
-
-By using chrome alum instead of ordinary alum, together 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 neutral
-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 addition 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.
-
-The chrome tan is used only to a limited extent in the tanning of furs,
-the method requiring very careful treatment 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 possesses great resistance to the action of water.
-
-Any salt of chromium, with either mineral or organic acids, can be used,
-but chrome alum is the one most commonly employed. If a skin is entered
-directly into a solution of a chrome salt made basic with an alkali, the
-precipitation 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 solution 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 lbs. of chrome alum are dissolved in 10 gallons of water.
-The skins are entered into the solution at about 70 deg. 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 1/2% solution containing 2/3% 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 practical use. The principle
-involved is identical with that of the preceding mineral processes.
-
-
-3. CHAMOIS TAN
-
-The chamois dressing, as previously noted, is undoubtedly 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 object of the fat was to coat the fibres of the skin,
-thus preventing 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 contradistinction 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 extent, 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 saponification, 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 degree are affected by contact with the air, due to the absorption
-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 on the basis of this phenomenon of absorbing oxygen from the
-air, those possessing this quality to a great degree being 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-drying 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.
-
-[Illustration: FIG. 8. TRAMPING MACHINE OR "KICKER."
-
-(_F. Blattner, Brooklyn, New York._)]
-
-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 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 drying
-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 tanning 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.
-Instead they are placed in small drums, together with metal balls of
-varying sizes and weights depending on the particular 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.
-
-[Illustration: 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 greatest
-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 or physical phase of the chamois tan.
-The chemical phase, if it takes place at all, is usually slight, and
-is merely incidental. 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 mixture 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 sulphonated 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 tanning 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 formaldehyde, 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, nevertheless these
-destructive agents seem to be repelled.
-
-Numerous processes have been devised which use formaldehyde in connection
-with other substances for tanning. Thus in a German patent is described
-a method involving the alternate or simultaneous treatment of pelts
-with solutions of formaldehyde and alpha or beta naphthol. 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 combination 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 eliminated
-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 following: 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
-regular chrome tan solution is added 1/2 lb. of formaldehyde for every 10
-gallons of chrome liquor. The rest of the process is as ordinarily.
-
-
-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. However, 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 receive a vegetable
-tan, which improves the quality of the leather to a considerable extent.
-
-
-Comparison of The Various Tanning Methods
-
-In 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
-requiring 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 undoubtedly 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 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, producing on drying, a hard, stiff leather.
-The chrome tan is especially impervious to water, easily resisting
-temperatures of 80 deg. C., and even boiling water. It is employed to only
-a limited extent on account of the special effort and care required
-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 combinations 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 temperatures 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 because 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 solutions. Thus in plain
-water, three furs, all tanned by the acid-salt tan, had shrinking points
-varying by several degrees; 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 4 deg. C. 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 shrinking 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 resistance of the skins to heat, especially with
-chamois-tanned furs. The experiments in this case were made by first
-treating 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 degrees 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:
-
-                  TABLE I
-  +-------------------+------+------+------+
-  |                   |  A   |  B   |  C   |
-  |                   | S.P. | S.P. | S.P. |
-  +-------------------+------+------+------+
-  |_Salt-acid Tan_    |  C.  |  C.  |  C.  |
-  |Australian Opossum |  46 deg. |  58 deg. |  45 deg. |
-  |Marmot             |  45 deg. |  50 deg. |  42 deg. |
-  |Skunk              |  47 deg. |  56 deg. |  43 deg. |
-  |                   |      |      |      |
-  |_Chamois Tan_      |      |      |      |
-  |Mink               |  52 deg. |  61 deg. |  45 deg. |
-  |Muskrat            |  50 deg. |  58 deg. |  42 deg. |
-  +-------------------+------+------+------+
-    A--Water
-    B--Water plus 1% Ammonia (s.g. 0.910)
-    C--Water plus 1% Sulphuric acid (66 deg.
-        Beaume)
-
-                  TABLE II
-  +-------------------+------+------+------+
-  |                   |  A   |  B   |  C   |
-  |                   | S.P. | S.P. | S.P. |
-  +-------------------+------+------+------+
-  |_Salt-acid Tan_    |  C.  |  C.  |  C.  |
-  |Australian Opossum |  53 deg. |  52 deg. | 54 deg.  |
-  |                   |      |      |      |
-  |_Chamois Tan_      |      |      |      |
-  |Mink               |  59 deg. |  59 deg. |  59 deg. |
-  +-------------------+------+------+------+
-    A--1000 c.c. water plus 40 c.c.
-        Peroxide plus 5 c.c. ammonia
-    B--500 c.c. water plus 2 grams Ursol D
-        (Para-phenylene-diamine)
-    C--500 c.c. water plus 5 grams Ursol D
-
-                      TABLE III
-  +-------------------+------+------+------+------+
-  |                   |  A   |  B   |  C   |  D   |
-  |                   | S.P. | S.P. | S.P. | S.P. |
-  +-------------------+------+------+------+------+
-  |_Salt-acid Tan_    |  C.  |  C.  |  C.  |  C.  |
-  |Australian Opossum |  51 deg. |  51 deg. |  53 deg. |  56 deg. |
-  |                   |      |      |      |      |
-  |_Chamois_          |      |      |      |      |
-  |Mink               |  59 deg. |  59 deg. |  61 deg. |  62 deg. |
-  +-------------------+------+------+------+------+
-    A--500 c.c. water plus 5 grams ground
-        nut-galls
-    B--300 c.c. water plus 2 grams pyrogallic
-        acid
-    C--500 c.c. water plus 2 grams potassium
-        bichromate
-    D--Water, after treating leather with
-        rapeseed oil
-
-                      TABLE IV
-  +-------------------+------+------+------+------+
-  |                   |  A   |  B   |  C   |  D   |
-  |                   | S.P. | S.P. | S.P. | S.P. |
-  +-------------------+------+------+------+------+
-  |_Salt-acid Tan_    |  C.  |  C.  |  C.  |  C.  |
-  |Australian Opossum |  49 deg. |  49 deg. |  55 deg. |  50 deg. |
-  |                   |      |      |      |      |
-  |_Chamois Tan_      |      |      |      |      |
-  |Mink               |  59 deg. |  67 deg. |  69 deg. |  70 deg. |
-  +-------------------+------+------+------+------+
-    A--500 c.c. water plus 5 c.c. formaldehyde
-        for 1 hour
-    B--500 c.c. water plus 5 c.c. formaldehyde
-        for 12 hours
-    C--500 c.c. water plus 10 c.c. formaldehyde
-        for 3 hours
-    D--As in C, but treated with 500 c.c. water
-        plus 5 c.c. ammonia, instead of water
-        alone.
-
-            TABLE V
-  +-------------+------+------+
-  |             |  A   |  B   |
-  |             | S.P. | S.P. |
-  +-------------+------+------+
-  |             |  C.  |  C.  |
-  |Persian Lamb |  44 deg. |  54 deg. |
-  |Astrachan    |  47 deg. |  55 deg. |
-  +-------------+------+------+
-    A--Before dyeing
-    B--After dyeing
-
-As a result of these experiments it may be concluded that the maximum
-temperature for drying salt-acid tanned skins should be 40 deg. C., while
-for chamois tanned skins the temperature may be permitted to reach 45 deg. C.
-without any danger of the leather being affected. Moreover, in the case
-of pickled skins, the matter of extraction of the tanning agent, as well
-as that of the leather becoming "burned" may be effectively counteracted
-by brushing some oil or fat on to the leather side before dyeing the pelt.
-
-The shrinking points of skins dressed by the various tanning methods are
-constant within certain limits, depending on the nature of the skin and on
-the conditions of tanning, and it is possible by observing the shrinking
-point, in conjunction with other characteristics of a given pelt, to
-determine what method of tanning was used.
-
-
-
-
-CHAPTER VI
-
-FUR DRESSING
-
-DRYING AND FINISHING
-
-
-One of the most important operations of all the fur dressing processes is
-the drying of the skins. For even when all the previous steps have been
-successfully completed, there is still a great possibility of the skin
-being injured if the drying is not properly and carefully carried out.
-
-The essential requirements for good drying are proper temperature,
-uniformity and rapidity. The leather part of the fur cannot, in the
-moist state, resist temperatures exceeding about 45 deg. centigrade, for when
-dried, the skin turns out hard and stiff, and cracks easily. The furs must
-therefore be dried at an initial temperature of 25 deg. to 30 deg. centigrade, and
-as the moisture is gradually removed, the temperature may be raised, for
-the less water that remains in the pelt, the less is the leather affected
-by the heat, and the more difficult is the removal of its aqueous content.
-
-If the drying process is not a uniform one, that is, if all the skins
-in a lot are not subjected to the same drying conditions, then after the
-drying has proceeded for a certain time, some skins may be quite dry while
-others are not, or there may be as many different degrees of dryness as
-there are skins drying. There is also the possibility of great variation
-in the amount of moisture removed from different parts of the same skin.
-Such a state of affairs requires an extra expenditure of time, labor
-and heat power in order to get the whole lot of furs into a more or less
-uniform condition. Moreover in some kinds of furs, especially those with
-thick skins, when the drying is not even, there is danger of the epidermal
-layer drying away from the corium, and subsequently peeling and cracking.
-Uniformity of drying requires the maintenance of a reasonably constant
-temperature equally distributed throughout all parts of the space where
-the drying is done, so that all the furs may be dried under the same
-conditions.
-
-Rapidity of drying is desirable not only because it is beneficial to
-the condition of the pelt, but also from the point of view of practical
-business economy. The space occupied by the drying should be as small
-as possible compatible with the volume of work, and with the efficiency
-of operation. Slow drying involves the use of much space to take care of
-all the skins to be dried, or an accumulation of pelts ready to be dried,
-neither of which conditions is efficient or desirable.
-
-It was formerly the general custom, still practised in some
-establishments, to dry the skins by hanging them up, leather-side out on
-lines in a large room or loft, the heat being usually supplied by steam
-pipes. Such a procedure occupied often as long as two or three days to
-get complete drying, involved a great deal of labor, and the results were
-far from uniform. In fact, in order to get the skins more nearly equable,
-it was necessary to subject them to an additional operation. This usually
-consisted of rotating the skins in a closed drum for several hours, the
-constant intermingling of the pelts in contact with each other causing
-any moisture left in them to be evenly distributed throughout the whole
-lot. The skins, by this process also are rendered somewhat softer and more
-flexible, but by drying under proper conditions the entire extra operation
-can be dispensed with, the furs coming out quite as soft and flexible
-without the drumming.
-
-A great improvement was the adoption of large fans to circulate the heated
-air in the loft, thereby approaching more nearly an even temperature.
-More modern devices have, however, been developed, whereby drying can be
-effected in the most uniform manner, with perfect control of temperature,
-and requiring the least possible consumption of space, time, labor and
-power. A typical arrangement consists of a large closed chamber, generally
-constructed of steel, and divided into several compartments each of which
-may be operated independently of the others. Air, heated over suitably
-located steam pipes to the required temperature, is forced through the
-various compartments by means of fans operated by power. The conditions
-may be varied in each compartment, as to temperature or humidity, both
-of which can easily be regulated, or all the compartments may be used
-together as one unit. The skins are hung up on rods or lines in the
-compartments, or on special frames for the purpose, which are then entered
-into the compartments and the doors shut. The dry, heated air is forced
-to pass over the skins, and takes up their moisture. At the further end
-of the drying chamber is another fan which removes the moisture-laden air
-after it has done its work. The drying is effected in from 6 to 24 hours,
-and all skins are obtained in the same condition, for the process is quite
-uniform and regular.
-
-Within recent years there has been evolved a highly efficient and
-economical drying equipment, based on a somewhat different principle
-than underlies any of the foregoing methods. The conveyor type of dryer,
-as it is called, is admirably suited to the needs of the fur dressing
-and dyeing industry, and is undoubtedly superior to any of the previous
-systems of drying furs, in that it affords an enormous saving of space,
-time, labor and power, and gives greater uniformity and presents better
-working conditions.
-
-[Illustration: FIG. 10. DIAGRAMMATIC VIEWS OF CONVEYOR DRYER. _a._ SIDE
-VIEW; _b._ END VIEW.
-
-(_Proctor & Schwartz, Inc., Philadelphia._)]
-
-The conveyor dryer consists essentially of a steel enclosure, through
-which the skins pass on horizontal conveyors. Where special insulation
-is necessary, asbestos panels are used to line the enclosure, making the
-dryer absolutely fireproof, and enabling the maximum utilization of heat.
-In the middle of the dryer are located the steam coils which furnish
-the heat, and in many instances exhaust steam can be used as the source
-of heat. Figure 10 shows diagrammatically the arrangement and operation
-of the conveyor type of dryer. The enclosure is divided into several
-compartments, in each of which a different condition of temperature and
-humidity is maintained, the temperature being closely and accurately
-regulated by an automatic control, and once the dryer has been set for
-any condition, all skins will be dried exactly the same, regardless of
-weather or season.
-
-[Illustration: FIG. 11. CONVEYOR DRYER.
-
-(_Proctor & Schwartz, Inc., Philadelphia._)]
-
-The skins to be dried are placed on poles which in turn are set on
-the horizontal conveyors as in Fig. 11. As the skins pass through the
-compartments, large volumes of air, heated to the required temperature
-over the steam coils, are circulated among the skins by means of the fans.
-Exhaust fans, properly placed, remove a certain quantity of moisture-laden
-air when it has accomplished its full measure of work. When the skins on
-the conveyors have passed the full length of the dryer, they are entirely
-dry, and are then removed from the poles. (Fig. 12). The time required
-for drying varies according to the nature of the fur from 1-2 hours to 6-8
-hours. In tests made to determine the relative efficiency of the conveyor
-type of dryer as against the old "loft" method, it was found that there
-was a saving of over 50% in power, and of 85% in floor space, as well as
-a great saving of labor, when the conveyor system was used, the number
-of skins dried in a given period of time being the same in both cases.
-The advantages of the new method are easily apparent, and the saving
-is sufficiently great with large lots of furs, to make an appreciable
-difference in the final cost of dressing.
-
-If the skins have been dried by a modern drying system they all come out
-in a uniform condition, and are ready to go on immediately to the next
-operation. If, however, a form of the "loft" method of drying has been
-used, it is customary to subject the skins to an additional process. The
-dried pelts are put in drums with damp sawdust, and drummed for a short
-time in order to get them into the proper condition. The drumming is
-essential for the purpose of equalizing the condition of the pelts, some
-being drier than others, and as a consequence of the contact with the
-moist sawdust, they are all brought to the same degree of dryness. As a
-result of this operation also, the skins become considerably softened.
-
-[Illustration: FIG. 12. DELIVERY END OF CONVEYOR DRYER.
-
-(_Proctor & Schwartz, Inc., Philadelphia._)]
-
-Then if the pelts have not been previously oiled during the tanning
-process, or prior to the drying, they receive this treatment now. The oil
-or fat is applied to the leather side of the furs, which are then placed
-in the tramping machine for a short time in order to cause the oil to be
-forced into the skin. The fibres of the corium thus become coated with a
-thin layer of fatty material, which contributes greatly to the softness
-and flexibility of the pelt, and increases its resistance to the action of
-water, and also, in certain instances a partial chamois tan is produced,
-thereby improving the quality of the leather.
-
-[Illustration: FIG. 13. STRETCHING MACHINE FOR CASED SKINS.
-
-(_Reliable Machine Works, Evergreen, L. I._)]
-
-The skins are now returned to the work bench, and subjected to the
-stretching or "staking" process. This consists in drawing the skin in all
-directions over the edge of a dull blade, which is usually fixed upright
-in a post with the edge up. Or, the stretching may be done on the fleshing
-bench, substituting a dull blade for the fleshing knife. Recently staking
-machines are being used in the larger establishments, the work being
-done much more quickly and efficiently. As a result of this operation,
-the leather becomes very soft and flexible, every bit of hardness and
-stiffness being eliminated, and the skins receive their maximum stretch,
-thereby giving the greatest possible surface to the pelage. This not only
-helps to bring out the beauty of the hair, but is also a decided advantage
-from the economic point of view, as a considerable saving of material
-is effected in this way, sometimes even to the extent of twenty-five per
-cent. Cased skins are stretched in a somewhat different manner, by means
-of stretching irons. These consist of two long iron rods joined by a pivot
-at one end. The skins are slipped on to the irons, which are then spread
-apart, and in this way the skins are stretched and softened. A machine
-which does this work very efficiently is shown in Fig. 13. The skin is
-drawn onto the stretching arms, in this case made of bronze, which are
-then forced apart by pressing on a pedal. When properly stretched to the
-maximum width in all directions possible, and thus thoroughly softened,
-the skin can easily be reversed, that is, turned hair-side out. As many as
-6000 skins can be stretched, or 4000 to 5000 skins stretched and reversed
-by one man in one day on such a machine.
-
-[Illustration: FIG. 14. FUR BEATING MACHINE.
-
-(_S. M. Jacoby Co., New York._)]
-
-The pelts are then combed and beaten. In smaller plants these operations
-are done by hand, but suitable machines are being employed. In order to
-straighten out the hair, it is combed or brushed. Then in order to loosen
-up the hair, and to cause it to display its fullness, the furs are beaten.
-This process is also done by hand in some establishments, but up-to-date
-places use mechanical devices for this purpose. A type of machine which
-has proven very successful, and is enjoying considerable popularity
-is shown in Fig. 14. These machines are also made with special suction
-attachments which remove all dust as it comes out of the beaten skin,
-thereby making this formerly unhealthful operation thoroughly sanitary
-and hygienic.
-
-The final process is drum-cleaning. This operation is intended
-specifically for the benefit of the hair part of the fur, and is very
-important inasmuch as the attractive appearance of the fur depends largely
-upon it. The drum, such as is shown in Fig. 15 is generally made of wood,
-or sometimes of wood covered with galvanized iron. The skins together with
-fine hardwood sawdust are tumbled for 2 to 4 hours, or sometimes longer.
-Occasionally a little asbestos or soapstone is added to the sawdust; for
-white, or very light-colored skins, gypsum or white sand is used, either
-alone, or in admixture with the sawdust; and for darker skins, graphite or
-fine charcoal is sometimes added in small quantities. The drum-cleaning
-process polishes the hair, giving it its full gloss and lustre, and at
-the same time absorbing any oil or other undesirable matter which may be
-adhering to the hair as a result of the washing and tanning processes.
-Any soap, or traces of mordant are wiped off and so removed, and by using
-heated sawdust, or heating the drum while rotating, the fur acquires a
-fullness and play of the hair which are great desiderata in furs. The
-sawdust must then be shaken out of the furs. This is done by cageing. In
-some instances, the drum itself can be converted into a cage, by replacing
-the solid door with one made of a wire screen. (Fig. 16.) Usually,
-however, the skins are removed from the drum and put in a separate cage,
-which is built like the drum, but has a wire net all around it, through
-which the sawdust falls, while the skins are held back. The cages are
-generally enclosed in compartments in order to prevent the sawdust from
-flying about and forming a dust which would be injurious to the health of
-the workers. In large establishments, the drum-cleaning machinery occupies
-a large section of the plant, many drums and cages being used, and special
-arrangements being made to take care of the sawdust which can be used over
-again several times, until it becomes quite dirty.
-
-[Illustration: FIG. 15. DRUM. (COMBINATION DRUM AND CAGE AS A DRUM.)
-
-(_F. Blattner, Brooklyn, New York._)]
-
-[Illustration: FIG. 16. CAGE. (COMBINATION DRUM AND CAGE AS A CAGE.)
-
-(_F. Blattner, Brooklyn, New York._)]
-
-With this operation ends the ordinary procedure of fur dressing. But
-there are several additional processes required in the treatment of
-certain furs, which are generally undertaken by the dresser, and chief
-among these are shearing and unhairing. Sometimes this work is done in
-separate establishments organized solely for this business. Certain kinds
-of furs, among them being seal, beaver and nutria, possess top-hair which
-may detract from the beauty of the fur, the true attractiveness being in
-the fur-hair. The top-hairs are therefore removed, and for this purpose
-machines are now being used. Formerly this work was all done by hand, and
-on the more expensive furs like seal and beaver, unhairing is now done on
-a machine operated by hand. The principle of the process is as follows:
-The skins are placed on a platform and the hair blown apart by means of
-a bellows. The stiff top-hairs remain standing up, and sharp knives are
-brought down mechanically to the desired depth, and the hair is cut off
-at that point. The skin is then moved forward a short distance, and the
-process repeated until all the top-hairs have thus been cut out. With
-muskrats, or other pelts which do not require such very careful attention,
-the whole process is done automatically on a machine. The fur-hair is
-brushed apart by means of brushes and a comb, and at regular intervals,
-sharp knives cut off the top-hairs. Several hundred skins can be unhaired
-in a day on such a machine requiring the attention of only one man. A
-machine for unhairing skins is shown in Fig. 17.
-
-[Illustration: FIG. 17. UNHAIRING MACHINE.
-
-(_Seneca Machine & Tool Co., Inc., Brooklyn, N. Y._)]
-
-With other furs, such as rabbits, hares, etc., where the trouble of
-unhairing would be too great commensurate with its advantages, the hair
-is sheared instead. The top hair is cut down to the same length as the
-under-hair by means of shearing machines which can be regulated to cut to
-any desired length of hair. A typical device for shearing furs is shown
-in Fig. 18.
-
-[Illustration: FIG. 18. FUR-SHEARING MACHINE.
-
-(_Seneca Machine & Tool Co., Inc., Brooklyn, N. Y._)]
-
-
-
-
-CHAPTER VII
-
-WATER IN FUR DRESSING AND DYEING
-
-
-The assertion has often been made, although its absurdity is now quite
-generally realized, that the success of the European fur dressers and
-dyers, particularly in Leipzig, is due to the peculiar nature of the
-water used, which is supposed to be especially suited for their needs.
-The achievements in this country in the fur dressing and dyeing industry
-during the past few years are ample and sufficient answers to the claim of
-foreign superiority in this field no matter what reason may be given, and
-particularly when the quality of the water used is advanced as a leading
-argument. For the water employed by the establishments in and about New
-York, as well as in other sections of the country is surely not the same
-as the water of Leipzig, yet the work done here is in every respect the
-equal of, if not better than the foreign products.
-
-It is interesting to note that similar rumors were current here in the
-early period of the development of the American coal-tar industry since
-1914. Our efforts to establish an independent dyestuff industry were
-doomed to failure, according to those who circulated the stories, because
-we did not have the water, which they claimed was responsible for the
-German success. The present status of the American dye business, in its
-capacity satisfactorily to supply most of the needs of this country and
-of others as well, speaks for itself.
-
-However, as is often the case with such erroneous assertions, there
-is just enough of an element of truth in the statement regarding the
-peculiar qualities of certain kinds of water, to make the matter worthy
-of consideration. Water is certainly a factor of great importance in fur
-dressing and dyeing, and it is not every sort of water that is suitable
-for use. This fact was recognized by the early masters of the art, for
-they invariably used rain-water as the medium for their tanning and dyeing
-materials, and their choice must be regarded as an exceedingly wise one.
-While the necessity for giving consideration to the quality of the water
-for fur dressing purposes is great, it is in fur dyeing that the effects
-of using the wrong water are largely evident, and so extra care must be
-exercised in the selection of water for this purpose.
-
-The essential requirements for a water suitable for the needs of the
-fur dressing and dyeing industry, are: first, a sufficient, constant
-and uniform supply; and second, the absence of certain deleterious
-ingredients. Chemically pure water is simply the product of the
-combination of two parts by volume of hydrogen with one part by volume
-of oxygen. Such water can only be made in the laboratory, and is of no
-importance in industry. For practical purposes, distilled water may be
-regarded as the standard of pure water. Here, too, the cost and trouble
-involved in the production of distilled water on a large scale is
-warranted only in a certain few industrial operations. A natural source
-of water which in its character most nearly approaches distilled water
-is rain. In fact, rain-water is a distilled water, for the sun's heat
-vaporizes the water from the surface of the earth forming clouds, which
-on cooling, are condensed and come down as rain. Rain-water is usually
-regarded as the purest form of natural water. Exclusive of the first
-rain after a dry period, rain-water is quite free of impurities, except
-possibly for a small percentage of dissolved atmospheric gases, which
-are practically harmless, and which can usually be readily eliminated
-by heating the water. Moreover, rain-water is quite uniform in its
-composition throughout the year in the same locality, and it possesses
-all the desirable qualities of a water suited for fur dressing and dyeing
-purposes. Formerly when the quantity of water used in the industry
-was comparatively small, the supply from rain was sufficient to meet
-all the requirements. But now, when tremendous quantities of water are
-used constantly, rain-water is no longer a feasible source, and other
-supplies must be utilized, although in a sense, all water may be traced
-to rain-water as its origin.
-
-When rain-water falls on the earth it either sinks into the ground until
-it reaches an impervious layer, where it collects as a subterranean
-pool, forming a well, or continues to flow underground until it finally
-emerges at the surface as a spring; or on the other hand the rain-water
-may sink but a short distance below the surface, draining off as ponds,
-lakes or rivers. In the first case the water is called ground water, in
-the latter it is known as surface water. Ground water usually contains
-metallic salts in solution, and relatively little suspended matter. If
-the water has percolated through igneous rocks, like granite, it may be
-quite free even of dissolved salts, and such water is considered "soft."
-If, however, the rocky formations over which, or through which, the water
-has passed contain limestone or sandstone, or the like, salts of calcium
-and magnesium will be dissolved by the water. The presence of the lime
-and magnesia salts, as well as salts of aluminum and iron, in the water,
-causes it to be what is termed "hard." Surface water is more likely to
-contain suspended matter, with very little of dissolved substances.
-Suspended matter, like mud, contains much objectionable matter such
-as putrefactive organisms and iron, but most of these materials can be
-removed by filtration or sedimentation, and seldom cause any difficulties.
-
-Hardness in water is generally the chief source of trouble when the water
-is at fault. Hardness may be of two kinds, either permanent, or temporary,
-or sometimes both are found together. Water which is permanently hard
-usually contains the lime and magnesia combined as sulphates. Temporary
-hardness, on the other hand, is due to the presence of lime and magnesia
-in the form of bicarbonates, the carbon dioxide contained in the water
-having dissolved the practically insoluble carbonates:
-
-   CaCO{3} + CO{2} + H{2}O = Ca(HCO{3}){2}
-   calcium   carbon  water      calcium
-  carbonate  dioxide          bicarbonate
-
-Temporary hardness can be eliminated by heating the water, the carbon
-dioxide being expelled and the carbonates of lime and magnesia being
-precipitated and then filtered off. Both permanently and temporarily hard
-waters can be softened by the addition of the proper chemical, such as
-an alkaline carbonate like sodium carbonate. This precipitates insoluble
-carbonates of the lime, magnesia, iron and aluminum, leaving a harmless
-salt of sodium in solution in the water. The sludge is allowed to settle
-in tanks before the water is used.
-
-In fur dressing and dyeing, water is employed for soaking and washing the
-skins, dissolving chemicals, extracts and dye materials, and also for
-steam boilers. A small amount of hardness in the water is not harmful,
-and up to 10 parts of solid matter per 100,000, may be disregarded.
-Permanent hardness is particularly objectionable in water for boiler
-purposes, as it forms scale. The effect of the impurities of the water
-depends on the nature of the chemicals and dyes used. Where acids are
-used in solution compounds of magnesium, lime and aluminum will generally
-not interfere. Hard water must not be used for soap solutions, as sticky
-insoluble precipitates are formed with the soap by the metals, this
-compound adhering to the hair, and being difficult to remove, will cause
-considerable trouble in subsequent dyeing. An appreciable loss of soap
-also results, as one part of lime, calculated as carbonate will render
-useless twelve parts of soap. In tanning or mordanting, where salts of
-tin, aluminum or iron are employed, hard water should not be used, as lime
-and magnesia will form precipitates with them. Bichromates will be reduced
-to neutral salts, and cream of tartar will also be neutralized. With dyes
-also, hard water has a deleterious effect. Basic dyes are precipitated by
-this kind of water, rendering part of the dye useless, and also causing
-uneven and streaky dyeings. Sometimes the shades of the dyeings are
-modified or unfavorably affected. Considerable quantities of lime and
-magnesia in the water will cause duller shades with logwood and fustic
-dyeings. The presence of iron, even in very slight quantities generally
-alters the shade, darkening and dulling the color.
-
-These facts were apparently all recognized and understood by the fur
-dressers and dyers of an earlier period, for instead of utilizing the
-water of lakes and streams near at hand, which afforded a more constant
-supply, but which contained harmful impurities, they collected the
-rain-water, which was always soft. Whether they realized the nature
-and character of the substances that make water hard is uncertain,
-but they were always careful to avoid such water. At the present time
-establishments located in and about large cities like New York, where
-the majority of American fur dressing and dyeing plants are situated,
-have no trouble about the water. The cities supply water which is soft,
-suitable alike for drinking and industrial purposes. Other plants, not
-so fortunately situated, often have to employ chemical means to treat the
-water so as to make it suitable for use.
-
-
-
-
-CHAPTER VIII
-
-FUR DYEING
-
-INTRODUCTORY AND HISTORICAL
-
-
-In discussing fur dyeing, the question naturally arises, "Why dye furs at
-all? Are not furs most attractive in their natural colors, and therefore
-more desirable than those which acquire their color through the artifices
-of man?" The answer cannot be given simply. Natural furs of the more
-valuable kinds are indeed above comparison with the majority of dyed furs.
-Yet there are several reasons which fully justify and explain the need
-for fur dyeing, for at the present time, this branch of the fur industry
-is almost as important and indispensable as the dressing of furs.
-
-The first application of dyeing to furs, had for its purpose the
-improvement of skins which were poor or faulty in color; or rather, the
-object was to hide such defects. As nearly as can be ascertained, this
-practise was instituted at some time during or before the fourteenth
-century, for fur dyeing seems to have been common during that period, as
-is apparent from the verses of a well-known German satirist, Sebastian
-Brant, who lived in the latter part of the fourteenth century:
-
-    "Man kann jetzt alles Pelzwerk faerben,
-    Und tut es auf das schlechste gerben."
-
-However, at a later period, there was a general condemnation of the dyeing
-of furs, and among the list of members of the furrier's guilds, none can
-be found who are described as dyers. There is a record of a decree issued
-by a prince in a German city in the sixteenth century, prohibiting the
-practise of fur dyeing. Inasmuch as furs were worn only by the nobility
-and certain other privileged classes, and also were very costly, there
-was great profit to be had by dyeing inferior skins so as to disguise the
-poor color, and then selling such furs at the price of superior quality
-skins. This was undoubtedly the reason for the prohibitory decree, but
-there were some who continued to practise the forbidden art in secret,
-using secluded and out-of-the-way places for their workshops, and mixing
-their carefully-guarded recipes with as much mystery as the witches did
-their magic potions. These circumstances probably account for the great
-amount of mystery which has been, and still is to a considerable degree,
-attached to fur dyeing, and also explains the opprobrium and distrust with
-which fur dyers were formerly regarded.
-
-Even at the present time, dyeing is often employed to improve furs which
-are faulty in color. It frequently happens, that in a lot of skins there
-are some which are considerably off shade, or in which the color is such
-as to appreciably reduce their value below the average, the hair being
-usually too light a shade, or of uneven coloring. By carefully dyeing
-these skins of inferior color, they can be made to match very closely
-the best colored skins of the particular lot of furs, and consequently
-increase their value. With most of the cheaper kinds of furs, the trouble
-and cost of improvement by dyeing would not be worth while today; but with
-some of the more valuable furs, and especially such as are very highly
-prized, like the Russian sable, or marten, or chinchilla, the darkening
-of light skins by the skillful application of fast dyes to the extreme
-tips of the hair, will increase their value sufficiently to warrant the
-expense. This dyeing or "blending" as it is called in such cases, is done
-in such a clever and artistic manner that only experts can distinguish
-them from the natural. Dyeing used for such purposes is not objectionable,
-provided the skins are sold as dyed or "blended."
-
-There are certain kinds of furs, such as the various lambs, Persian,
-Astrachan, Caracul, etc., which are never used in their natural color,
-because it is usually of a rusty brownish-black. These are furs possessing
-valuable qualities otherwise, so they are dyed a pretty shade of black,
-which brings out the beauty of the fur to the fullest extent. Sealskins
-are also dyed always. Formerly they were dyed a deep, rich dark brown,
-resembling the finest shades of the natural color, but now the seals are
-dyed black with a brownish undertone, a color quite different from the
-natural. While these two instances cannot be said to be cases of dyeing
-to disguise faulty color, they are examples of improvement of color by
-dyeing.
-
-Closely associated with the use of dyes to increase the value of a fur
-by improving its color, is the dyeing of skins of a certain lot of furs
-to produce a uniform shade, thereby facilitating or to a considerable
-degree eliminating the task of matching the skins by the furrier. This is
-usually done only on skins which are quite small, of which a great many
-are needed in the manufacture of fur garments, because the matching of
-several hundred skins would entail too much time and labor commensurate
-with the value of the fur. The most notable instance of the use of dyes to
-produce a uniform shade on furs is the case of the moleskin. Occasionally,
-furs are dyed after being made into garments, by careful application of
-dyes, in order to obtain certain harmonious effects, such as uniformity
-of stripe, or to produce a desired gradation of shade among the different
-skins comprising the garment.
-
-Not infrequently, the great variety of shades and color schemes which
-Nature provides in the different furs, becomes insufficient to satisfy the
-desire of the fur-wearing public for something new. The whims of fashion
-always require some novel effect, even though it be for only one season.
-To meet this demand for novelty, fantasy or mode shades are produced on
-suitable furs,--colors which do not imitate those of any animal at all,
-but which, nevertheless, strike the popular fancy. It often happens that
-such a color becomes quite popular, and enjoys a considerable vogue, to
-the great profit of those who introduced the particular color effect. The
-best ones, however, meet with only a comparatively short-lived demand,
-being soon superseded by different color novelties.
-
-The basis, though, of the greatest proportion of fur dyeing at the present
-time, is the imitation of the more valuable furs on cheaper or inferior
-skins. With the gradual popularization of furs as wearing apparel since
-the beginning of the last century, the demand for furs of all kinds
-has increased enormously. The supply of furs, on the other hand, and
-especially of the rarer kinds, has had difficulty in keeping pace with
-the requirements, and as a result there is a shortage. A very effective
-means of relieving this shortage, to a great degree, at any rate, is
-the dyeing of imitations of the scarcer furs on cheaper skins. There
-are many animals among the more common, and more easily obtainable ones,
-whose skins are admirably suited as the basis of imitations of the more
-costly furs. Some of the furs which are adapted for purposes of dyeing
-imitations are marmot, red fox, rabbit, hare, muskrat, squirrel, opossum,
-raccoon, and many others, and the imitations made are those of mink,
-sable, marten, skunk, seal, chinchilla, etc., and indeed, there are very
-few valuable furs, which have not been dyed in imitation on cheaper pelts.
-On account of the general mystery which formerly surrounded fur dyeing
-establishments, and which has persisted to this day, although to a lesser
-degree, many peculiar notions were held, even by those in the fur trade,
-concerning the production of imitations. The idea that in order to "make"
-a certain fur out of a cheaper skin, it was necessary to use the blood
-of the animal imitated, is typical of the conceptions of fur dyeing held
-not so long ago. To-day, while the knowledge generally possessed about
-this branch of the fur industry is meagre and vague, the air of mystery
-and secrecy has become somewhat clarified, and such ideas as are current
-about fur dyeing are more rational than formerly.
-
-The dyeing of imitations is quite an artistic kind of work, and indeed
-fur dyeing ought to be classed among the finest of industrial arts. Some
-of the reproductions achieved by dyers on a commercial scale are truly
-admirable. The possibility of imitating the finer furs on cheaper skins
-naturally led to abuse, the dyed furs being passed off frequently on the
-unsuspecting and uninformed buyer as the genuine original. In fact, this
-practise became so flagrant that in England laws were enacted to remedy
-the evil. At the present time, dyed furs are all sold as such, although
-there always may be some unscrupulous merchants who seek to profit by
-deception. Some of the imitations and the names of the furs for which they
-were sold, are as follows:
-
-  Muskrat, dyed and plucked        sold as seal
-  Nutria, plucked and dyed         sold as seal
-  Nutria, plucked and natural      sold as beaver
-  Rabbit, sheared and dyed         sold as seal or electric seal
-  Otter, plucked and dyed          sold as seal
-  Marmot, dyed                     sold as mink or sable
-  Fitch, dyed                      sold as sable
-  Rabbit, dyed                     sold as sable
-  Rabbit, dyed and sheared         sold as beaver
-  Muskrat, dyed                    sold as mink or sable
-  Hare, dyed                       sold as sable, fox, or lynx
-  Wallaby, dyed                    sold as skunk
-  White rabbit, natural            sold as ermine
-  White rabbit, dyed               sold as chinchilla
-  White hare, dyed or natural      sold as foxes, etc.
-  Goat, dyed                       sold as bear, leopard, etc.
-
-This list serves to indicate but a few of the great number of
-possibilities which are available for the fur dyer to produce imitations
-of the better classes of furs. Needless to say, these imitations cannot,
-as a general rule, equal the originals, because while the color is one
-of the most important features in judging the fur, the nature of the
-hair, gloss, waviness, thickness, and also the durability are essential
-considerations, and it is only in certain instances that skins used
-for imitations approach the originals in these respects. However, for
-the purposes and desires of the majority of people who wear furs, the
-imitations are deemed quite satisfactory, and they also have the advantage
-of being cheaper than the natural originals.
-
-For whichever reason furs are dyed, there is no doubt that the art of fur
-dyeing is one of the most difficult kinds of application of dye materials.
-In the dyeing of the various textiles, either as skein or woven fabric,
-the material is of a uniform nature, and therefore the dye is absorbed
-evenly by the fibres. Moreover, textiles are dyed at, or near the boil,
-the dyestuff being more uniformly and permanently taken up from solution
-by the fibre at elevated temperatures.
-
-How different is the case with furs! Far from being homogeneous, furs
-present the greatest possible diversity of fibres to be dyed. As already
-noted elsewhere, fur consists of two principal parts, the hair and the
-leather, differing widely in their actions toward dyes. As a general
-rule, the leather absorbs dyestuffs much more readily than the pelage,
-and inasmuch as fur dyeing is intended mainly and primarily to apply to
-the hair, there is usually an appreciable loss of dye material due to its
-being absorbed by the leather, and thereby rendered unavailable for dyeing
-the hair. This fact must be taken into account in the dyeing of furs, and
-the methods must be adapted accordingly.
-
-With reference to the hair itself, not only has each class of furs
-hair of a different kind, but even in the same group there is always a
-considerable divergence in the properties of the hair. The fur-hair, being
-more or less of a woolly nature, takes up the dye with comparative ease,
-while the top-hair is quite resistant to the action of all dye materials.
-As pointed out in the discussion of the nature of fur, on different parts
-of the same pelt the hair varies in its capacity for absorbing coloring
-matters. The color of the hair, also frequently presents a great variety
-throughout the skin, both in fur-hair and top-hair. Yet with all this lack
-of uniformity and homogeneity, the dyed fur must be of an even color,
-closely approaching the natural, gently graded and without any harsh or
-unduly contrasted effects. The natural gloss of the hair, one of the most
-valuable qualities of the fur, must be preserved. This is by no means
-a simple matter, for the luster is affected by dyes and chemicals with
-comparative ease, and especially careful treatment is necessary to prevent
-any diminution of the gloss.
-
-When the leather part of the fur is exposed to solutions of a temperature
-exceeding 40 deg.-50 deg. centigrade, it soon shrivels up or shrinks, and on
-drying the pelt, becomes hard and brittle, and therefore quite useless.
-Methods of fur dyeing have to take into consideration this fact, and the
-temperature of the dyebath must not be greater than 35 deg.-40 deg. centigrade. To
-be sure, certain dressings make furs capable of withstanding much higher
-temperatures, but their applicability is not universal, being suited only
-for a very limited special class of dyestuffs. (V. Fur Dressing). The
-necessity for employing comparatively low temperatures, coupled with the
-great resistance of the hair to the absorption of dye, even at much higher
-temperatures, makes fur-dyeing a very difficult operation indeed. Another
-obstacle which must be surmounted, is the possibility of extraction by
-the dye solution, of those materials, chemical or otherwise, which are
-contained in the leather, and which are the basis of its permanence,
-softness and flexibility. For in the majority of dressing processes, the
-action of the ingredients is a preservative one, and when these are wholly
-or partially removed from the leather during the dyeing, it becomes, on
-drying, hard and horny, like the original undressed pelt. In cases where
-furs are to be dyed, special dye-resisting dressings must be used, or the
-dyed skins must receive an additional dressing before drying.
-
-Dyeings on furs, to have any value, must possess great fastness to light,
-rubbing and wear, and must not change color in time, either when the furs
-are stored, or when made up into garments. The necessity for fur dyeings
-to have these properties, together with the difficulties outlined above,
-has greatly limited the field of available dyeing materials, as well as
-the methods of application. These will now be taken up in detail.
-
-
-
-
-CHAPTER IX
-
-FUR DYEING
-
-GENERAL METHODS
-
-
-Before the furs can be dyed, they have to undergo certain preparatory
-processes: first, killing, which renders the hair more susceptible to the
-absorption of the dye; and second, mordanting, which consists in treating
-the killed fur with chemicals which help the dye to be fixed on the hair.
-Then the skins are ready to be dyed.
-
-There are two principal methods by which dyes are applied to furs in
-practise: the brush process, whereby only the tips or the upper part
-of the hair are colored; and the dip process, whereby the entire fur,
-including the leather is dyed. All other procedures in fur dyeing
-are modifications or combinations of these two. Killing solutions and
-mordanting solutions are also applied by one of these methods, usually
-the dip process, although very frequently combinations of the brush and
-dip methods are used.
-
-Chronologically the brush method of dyeing came first. The early masters
-of the art were extremely fearful about employing any means by which
-there was a possibility of the leather being in any way affected. They
-naturally had to devise such methods as would give the desired effect
-in a satisfactory manner, and as would be confined solely to the hair
-part of the fur, leaving the leather untouched. By applying the dye
-or other material to be used, in the form of a paste with a brush, the
-upper portion of the hair only was treated. For different kinds of furs
-different sorts of brushes were used, and the depth to which the hair was
-colored could be controlled by skillful manipulation of the brushes. It
-was frequently necessary to give a ground color to the hair, the lower
-part being dyed a different shade from the tips. This was accomplished
-by spreading the dye paste over the hair with a broad brush, and then
-beating the color in with a specially adapted beating brush. With larger
-furs, two skins were placed hair to hair after the dye had been brushed
-on, and the color forced to the bottom of the hair by a workman tramping
-on the skins. The dyeing of seal was a typical illustration of these
-procedures. First the tips of the hair were dyed. The color was brushed
-on, allowed to dry, then the excess beaten out with rods. These operations
-were repeated until the proper depth of shade was obtained, often as many
-as a dozen or more applications of the dye being necessary. Then the base
-color was spread over the hair, and beaten or tramped in until the lower
-parts of the hair were penetrated. This process also required drying and
-beating out of the excess dye, as well as numerous applications of the
-dye to impart the desired color to the hair. Prior to the dyeing, the furs
-were killed, by brushing on a paste containing the essential ingredients,
-drying and beating and brushing the fur, just the same as in dyeing. It
-will be readily seen that such methods were exceedingly laborious, and in
-some cases the dyeing took many weeks, and even months.
-
-It was quite a step forward when a certain fur dyer, possessing a little
-more courage, or perhaps, experimenting spirit than the others, attempted
-to dye furs by dipping them entirely into a bath containing a solution
-of the dye instead of applying a paste as formerly. The advantages to be
-gained by such a method of dyeing were many. A large number of skins could
-be treated thus at one time, and this was a very important consideration
-in view of the great increase in the demand for dyed furs. By allowing the
-furs to remain in the dye solution until the proper shade was obtained,
-the time and labor of applying many coats of dye by brush was considerably
-reduced, and in addition, there was a greater probability of the products
-coming out all alike, uniformly dyed. The results as far as the hair
-was concerned, were indeed highly gratifying, but the condition of the
-leather after dyeing was not so encouraging. This difficulty has to a
-considerable degree been overcome, although there are frequent instances
-of the leather being affected by the dyeing process even with modern
-methods. However, the remedy in such cases, or rather the preventative
-is the proper dressing of the skins prior to the dyeing. The dip method
-of dyeing has acquired great importance, and is being employed in dyeing
-operations involving the handling of millions of skins annually. In
-certain instances, nevertheless, the brush method is of prime significance
-as in the dyeing of seal, and seal imitations on muskrat and coney,
-enormous quantities of furs being dyed in this fashion. In the majority
-of imitations dyed, both the brush and the dip methods must be used.
-
-Figure 19 illustrates the various types of brushes which are used at the
-present time for the application of the dye by the brush method. Each
-brush has a specific purpose and use. The procedure in brush dyeing is
-somewhat as follows. The skins, after being properly treated, that is,
-killed, and mordanted, are placed on a table, or work-bench, hair-side up.
-Then by means of a brush which is adapted to the nature and requirements
-of the particular fur, the solution is brushed on in the direction of
-the fall of the hair, occasionally beating gently with the brush so as to
-cause the dye to penetrate to the desired depth. Considerable skill and
-care must be exercised in this operation as it is rather easy to force
-the dye down further than is wanted, and in some cases the leather or the
-roots of the hair may be affected. The skin having received its coat of
-dye, is then dried and finished, if no other dyeing processes are to be
-applied. Frequently, with certain types of dyes, several applications of
-color are necessary, and these are brushed on as the first one, drying
-each time. Then, on the other hand, the skin may receive a dyeing in the
-bath by dipping, and for this also, the fur is first dried after the brush
-dyeing.
-
-[Illustration: FIG. 19. BRUSHES USED IN FUR DYEING BY THE BRUSH METHOD.]
-
-Quite recently, owing to the great quantities of furs which are being
-dyed as seal imitations, chiefly by the brush method, although the dip
-method is used in conjunction with it, machines have been invented to
-replace the hand brush, and the dye is now applied mechanically. Machines
-for this purpose are by no means new, there being records of inventions
-almost a score of years past, but they did not achieve much success.
-Brush-dyeing machines, to be efficient, must be designed to suit the
-needs of the particular type of fur to be dyed, otherwise there will be
-a great lack of uniformity in the dyed skins, a condition which cannot
-occur when the dye is brushed on by hand brushes. Figure 20A and B shows
-diagrammatically, machines invented within the past few years, which are
-used to dye mechanically furs by the brush process.
-
-[Illustration: FIG. 20. TYPES OF MACHINES FOR DYEING FURS BY THE BRUSH
-METHOD.
-
-_A._ (U. S. Patent 1,225,447.) _B._ (U. S. Patent 1,343,355.)]
-
-[Illustration: FIG. 21. DRUM FOR WORKING WITH LIQUIDS.
-
-(_Turner Tanning Machinery Co., Peabody, Mass._)]
-
-For the dipping process, the dye solution is prepared in vats, or
-liquid-tight drums, or in some instances in paddle arrangements. The
-skins are placed in the dye-bath, and the dyeing operation proceeds
-without any difficulty. After the proper shade is obtained, the furs
-are removed, washed free of excess dye, dried and finished. The dipping
-method is employed where a single shade is to be dyed on the fur, as the
-production of blacks on lambs. But in most cases, the dyeing in the bath
-is supplemented by the application of a coat of dye by the brush to the
-upper part of the hair, the color being usually a darker shade than the
-ground dyeing. Thus, for example, in the dyeing of imitation sable on
-kolinsky or a similar fur, the skins are first dyed the relatively light
-color of the under-hair by the dip process, then the dark stripe effect
-is brushed on.
-
-The blending of sables, martens, chinchillas or other rare furs, is not
-done in the same manner as with other furs, because each skin requires
-individual attention and a long and careful treatment. The dye solution
-is applied by means of very fine brushes or sometimes feathers, to the
-extreme tips of the hair, until the proper degree of color intensity is
-obtained. The time, labor, and skill necessary for this sort of work are
-warranted only in the case of the highest-priced furs, and the blendings
-are so excellent as to defy detection, except by experts.
-
-[Illustration: FIG. 22. DEVICE FOR CONVEYING SKINS.
-
-(_Turner Tanning Machinery Co., Peabody, Mass._)]
-
-After the furs have gone through all the operations required by the
-processes of killing, mordanting, dyeing and washing, they are ready to
-be dried and finished. The procedure is quite similar to that employed in
-fur dressing. Sometimes the leather side of the skins is brushed with a
-strong salt solution before drying, in order to replace some of the salt
-which was extracted during the dyeing processes. In other instances, a
-light coat of some oily substance is brushed on, to render the leather
-soft and flexible after drying, where there is a possibility of the skins
-turning out otherwise. Great care must be exercised in the handling of
-the dyed skins to avoid the formation of stains or spots on the hair,
-which might ruin the dyeing. As little handling of the furs as is feasible
-will reduce any trouble from this source. In conveying the wet skins
-from one part of the plant to another it is desirable to use a device
-such as is shown in Fig. 22. For drying, the same machines as described
-under Fur Dressing can be used, and similar care must be taken to avoid
-overheating or irregularity of drying. Drum-cleaning constitutes a very
-important operation in the finishing of the skins, the hair receiving
-a polish, and the full lustre and brilliancy of the dye being thereby
-brought out. Then after caging to remove the sawdust or sand, the skins
-are passed over the staking knife, or are treated in a machine suited
-for the purpose, to stretch them and to render them thoroughly soft and
-flexible. And therewith is concluded the work of the fur dyer proper, and
-the skins are ready to return to the furrier, in whose hands they undergo
-the metamorphosis into the fur garments to be worn chiefly by the feminine
-portion of humanity.
-
-
-
-
-CHAPTER X
-
-FUR DYEING
-
-"KILLING" THE FURS
-
-
-If dressed furs are treated with a paste or solution of a dye properly
-prepared, and at the right temperature, the hair will show very little
-tendency to absorb the coloring matter. Even after prolonged treatment
-with the dye, only a small amount will be taken up by the hair, and in a
-very irregular fashion. Soft, woolly hair, like that of lambs and goats
-will be colored more easily than that of furs with harder hair, and the
-under-hair of a fur will generally have a greater affinity for the dye
-than the harder and stiffer top-hair. Moreover, in some parts of the same
-fur, the hair will absorb more color than in other parts. In other words,
-the hair of furs resists the action of dye materials to a greater or less
-degree, depending upon the character of the fur, and also upon the part
-of the pelt. In order to overcome this resistance of the hair, and to
-render it uniformly receptive to the coloring substances, the furs are
-treated with certain chemical agents, the process being known technically
-as "killing."
-
-The origin of the term is obscure, but it is interesting to note that
-in the fur dyeing countries other than the United States and England,
-the corresponding expression is used: in Germany, "toeten," and in France
-"tuer." The explanation of the process is as follows: The surface of the
-hair is covered with a fine coat of fatty material which renders the hair
-more or less impervious to dye solutions and solutions of other substances
-which may be used for dyeing purposes. This fatty coating of the hair
-cannot be removed by mechanical means, otherwise the hair would have
-been freed of it during the dressing operations. Chemical solvents must
-therefore be resorted to, and naturally alkaline materials are used, these
-being usually cheapest and also most effective in their dissolving action
-on fatty substances. Alcohol, ether, benzine, and other similar liquids
-also serve as killing agents on furs, since they too, are fat solvents.
-In all these cases, the fatty substance on the hair is dissolved away,
-and the protective coat which previously rendered the hair impervious
-to the dye, is now removed. There are certain chemicals however, which
-normally do not dissolve substances of a fatty nature, but are strongly
-oxidizing, such as peroxide of hydrogen, hypochlorites, permanganates,
-perborates, nitric acid, etc., and exert a killing action when they are
-applied to the hair, in that the hair is made capable of taking up the
-dye from its solutions. In this case the killing can hardly be said to
-be due to a degreasing process. The fact that killing can be brought
-about with other substances than alkalies or fat solvents, has led to
-the belief on the part of some investigators in this field that killing
-is more than a degreasing operation, although the removal of the fatty
-material of the hair undoubtedly takes place. Some authorities consider
-that the killing process changes the pigment of the hair, which thereby
-becomes more receptive to the dye. It is quite possible that some such
-change in the structure of the hair fibre does take place, the surface
-of the hair becoming slightly roughened, and therefore more capable of
-fixing the coloring matter. The question is still an open one, and since
-no conclusive researches have been made as yet, it will be assumed that
-killing is simply a degreasing process, inasmuch as the modern practise
-is based on this supposition, and very satisfactory results are obtained.
-
-An account of the historical development of the killing process brings
-out many interesting and enlightening facts, so it will be given here
-briefly. One of the first substances used for killing, or degreasing the
-hair of furs, was decomposing urine. Urine contains about 2% of urea which
-gradually changes to salts of ammonia, and in the presence of the air,
-largely to ammonium carbonate. This substance has a weak alkaline action,
-but sufficiently effective to be used for killing the hair of certain
-types of furs. Woolly furs, such as those derived from the various kinds
-of sheep and goats, were degreased with stale urine, the skins being
-washed in this, and then rinsed in water. The fat was emulsified by the
-ammonium carbonate present, and could thus be easily removed. For other
-furs, a stronger mixture was necessary. An example of a killing formula
-used on wolf, skunk and raccoon, which were to be dyed black, is the
-following:
-
-  350 grams beechwood ashes
-  200 grams unslaked lime
-  150 grams copper vitriol
-  100 grams litharge
-   60 grams salammoniac
-   40 grams crystallized verdigris
-  3.5 liters rain water
-
-Beechwood ashes were a very important constituent of the old killing
-formulas. The reason for that lies in the fact that beechwood contains
-a comparatively high percentage of potassium, which occurs in the ashes
-of the burned wood as potassium carbonate, or potash. The ashes alone
-were frequently used, being applied in the form of a paste, which in
-some instances had an advantage over a solution, in that the killing
-could be limited to certain parts of the skin where it was more desired
-than in other parts. By extracting the wood ashes with hot water, and
-evaporating the clear solution to dryness, potash could be obtained, which
-was considerably stronger than the original ashes. Next in importance
-for the killing was unslaked lime. This substance was also often used by
-itself, being first slaked with water, and using the milk of lime thus
-formed, after cooling. Salammoniac, although a salt, and consequently
-without any killing action, in contact with the beechwood ashes or the
-lime in solution or paste, liberated ammonia slowly, and so also acted
-as a degreasing agent. The other chemicals in the formula took no part
-in the actual killing of the hair, but acted either as mordant materials
-or as mineral dyes. The copper salts, in this mixture present in two
-forms, as sulphate in copper vitriol, and as acetate in the verdigris,
-were important constituents of the dye formula, being essential to the
-production of the proper shade. These substances properly had no place
-in the killing formula. The litharge, also was not a killing agent, but
-in the presence of the alkaline materials of the killing mixture, it
-gradually combined with the sulphur contained in the hair, forming lead
-sulphide, and thereby darkening the color of the hair. In this case,
-the metallic compound acted, not as a mordant, but as a mineral dye. The
-mixture was applied to the hair by means of a brush, the skins let lie for
-some time, then dried, brushed and beaten. Many applications were usually
-necessary to sufficiently degrease the hair. Inasmuch as the killing paste
-was prepared by mixing the constituents together, and then was brushed
-on at the comparatively low temperatures which the proper protection of
-the hair required, it is questionable whether some of the metal compounds
-were even enabled to act as described above as mordant or dye. In spite of
-the trouble and considerable time required in working with such a killing
-formula to obtain the hair in the desired condition for dyeing, the use
-of such a mixture nevertheless possessed the advantage that the hair was
-only very slowly and gradually acted upon, and so the gloss was preserved.
-The action of strong alkaline substances acting quickly is more or less
-detrimental to keeping the gloss of the hair, while the slow action of
-the weak alkaline paste of the old formulas, and the gradual formation
-of a protective metal film on the surface of the hair, rendered the hair
-suitably receptive to the dye which was subsequently applied, without in
-any measure affecting the lustre of the hair.
-
-It would be needless to describe or discuss any more of the old killing
-formulas, for the principle involved was the same in all cases, there
-being usually a slight variation in the content of metallic salts,
-beechwood ashes and unslaked lime being constituents of the great majority
-of the mixtures used. Modern killing processes employ substances quite
-similar to those of the old formulas, the operations, however, being much
-less laborious and less time-consuming, and the cheap, pure products
-which chemical science has been able to develop being used in place of
-the crude products crudely obtained from natural sources. The chemicals
-used at the present time for killing furs, are chiefly ammonia, soda ash,
-caustic soda, and caustic lime. The choice of the killing agent depends
-upon the nature of the fur, the hair of some furs being sufficiently
-killed by treatment with weak alkalies, while in other furs the hair may
-require stronger treatment. The ability of the hair of a particular fur to
-withstand the action of the different alkaline substances must be taken
-into consideration, there being a great divergence in this regard among
-the different classes of furs. Raccoon, for example, is not appreciably
-affected by a solution of caustic soda of 5 degrees Beaume, while some
-wolf hair cannot withstand the action of a solution of soda ash of less
-than 1 degree Beaume. Frequently much stronger alkalies are necessary to
-kill the top-hair than the under-hair, so this accomplished by treating
-the skins in a solution which is suited to kill the under-hair, and
-subsequently the top-hair is treated with a stronger solution, this being
-applied by the brush method.
-
-Uniformity of action of the killing material on all parts of the skin,
-and on all the skins of a given lot, is absolutely essential to obtaining
-satisfactory results in dyeing. And it is by no means a simple matter
-to get such uniformity, considering the numerous factors that must be
-taken into account. Any operation involving the immersion of the skins
-in solutions or even in water alone, has an effect on the leather side of
-the skin, inasmuch as some of the tanning materials may be extracted. The
-application of some substance of a fatty nature to a great degree prevents
-this, and the skin can be killed, mordanted and dyed, and then come out
-soft and flexible. But the great majority of substances of a fatty nature
-are affected by alkalies, and so when the skins are being killed, the
-action of the alkaline materials would be upon the fat contained in the
-leather as well as that upon the hair. As a result the hair may not be
-sufficiently killed, and so give uneven dyeings subsequently. Either a
-certain excess of the killing chemical must be used, and it would be very
-difficult to ascertain what quantity would suffice, or the killing action
-must be prolonged; but best of all, in oiling the skins, an inert mineral
-oil should be used, since it is wholly unaffected by alkalies.
-
-Skins may be killed by the brush process or the dip process, or by both.
-For brush killing, the stronger alkalies like lime and caustic soda are
-used, the solution being applied to the top-hair with a suitable brush,
-and the skins allowed to remain hair to hair for the necessary length
-of time, after which they are treated further as skins killed by the dip
-process. By this latter process, the furs are immersed in a solution of
-the desired killing agent in a vat, or drum, or other appropriate device
-which will permit of uniform action of the alkali on the hair of all the
-skins. After remaining in the solution the required length of time, the
-skins are drained, and rinsed in fresh water, and then entered into a weak
-solution of an acid in order to neutralize any remaining alkali, it being
-easier to wash out acid than alkali. The furs are then washed thoroughly
-in clear water, preferably running water, to remove the last traces of
-acid. The skins are then drained and hydro-extracted, or pressed, and are
-then ready for the subsequent operations of mordanting and dyeing.
-
-
-KILLING WITH SODA
-
-Soda is sodium carbonate, which is produced commercially in a very pure
-state in several different forms, the chief being sal soda, which is
-crystallized sodium carbonate, containing about 37% of actual soda; and
-soda ash, or calcined soda, which is anhydrous sodium carbonate. The
-latter is the variety most commonly used.
-
-  10 grams soda ash are dissolved in
-   1 liter of water at 25 deg.-30 deg. C.
-
-The skins are immersed for 2-3 hours, after which they are rinsed and
-treated with
-
-  10 grams acetic acid dissolved in
-   1 liter of water.
-
-The skins are again thoroughly washed, and then hydro-extracted.
-
-
-KILLING WITH LIME
-
-Lime, calcium oxide, forms a white, amorphous, porous substance, which
-readily takes up water, giving calcium hydroxide, or slaked lime. Only the
-best grades of lime should be used, as it is very frequently contaminated
-with calcium carbonate and other inert materials.
-
-  10 grams of lime are dissolved in
-   1 liter of water.
-
-The skins are entered, and allowed to remain for a period of time which
-varies according to the nature of the fur. During the killing, the
-solution must be agitated, in order to evenly distribute the milk of lime,
-which has a tendency to settle out. After rinsing, the skins are "soured,"
-by treating with weak acetic acid solution, then thoroughly washed, and
-drained.
-
-
-KILLING WITH CAUSTIC SODA
-
-Caustic soda is used only on furs the hair of which is very hard and
-resistant to killing. Usually it is applied by the brush process, but in
-some instances, the dip method must be used. In order to reduce as far
-as possible, the action of the caustic soda on the leather, the weakest
-permissible solutions are used, increasing the time of treatment, if
-necessary. Caustic soda is a white, crystalline substance, occurring
-in commerce in lumps, but more conveniently in a solution of 40 degrees
-Beaume, containing 35% of caustic soda. Various quantities, ranging from
-4 to 25 grams of this solution per liter of water are taken, according to
-the character of the fur, and the skins treated for 2-3 hours, although
-weaker solutions may be used, and increasing the duration of the killing.
-By keeping the solution in motion, by means of a stirrer or any other
-method of agitation, the best results are obtained. After the skins are
-sufficiently killed, they are soured, and washed as by the other killing
-methods.
-
-Where the nature of the hair of the fur is such that the top-hair and
-the under-hair require different killing treatments, the skins are first
-killed by the dip process, with an alkali suited to kill the under-hair,
-then a brush killing with a stronger alkali is applied to the top-hair.
-The subsequent treatments are the same as for usual dip-killing methods.
-
-
-
-
-CHAPTER XI
-
-FUR DYEING
-
-MORDANTS
-
-
-The hair of furs has the peculiar quality of fixing the oxides or
-hydroxides of certain metals from dilute solutions of their salts.
-Advantage is taken of this property to mordant the furs, that is, to cause
-a certain amount of the metallic oxide or hydroxide to be permanently
-absorbed by the fibres. The term mordant comes from the French word
-"mordre," meaning to bite, it being formerly considered that the purpose
-of a mordant was to attack the surface of the hair in such a way as to
-permit the dye to be more easily absorbed. In fact, killing mixtures,
-which were intended for this same object, used to contain the various
-chemicals which have a mordanting action, in addition to the alkaline
-constituents. The mordants were not applied as such, but always as
-killing materials. It was later realized, however, that the mordant was
-instrumental in the production of the color itself.
-
-Mordanting may be considered as having a two-fold object: first, to help
-fix the dye on the fibre in a more permanent fashion, thus rendering the
-dyeings faster; and secondly, to help obtain certain shades of color, as
-the various mordants produce different shades with any given dye. Some
-classes of dyes can be applied to furs without the use of mordants, but
-other types are taken up only in a very loose manner, being easily washed
-out from the hair with water, and it is only when such dyes are brought on
-to the hair in the form of a metallic compound, producing what is known as
-a "lake," that really fast dyeings are obtained with them. The substances
-which are used for mordanting the hair are certain metallic compounds,
-but not all metallic salts which are used in dyeing are mordants.
-Sometimes such a compound is employed to develop the color of the dyeing
-by after-treatment, as in the case of after-chroming, the action of the
-metallic salt being directed only to the dye, and is not fixed by the
-fibre as a mordant must be. In order for a metallic compound to act as a
-true mordant, it must be fixed by the hair, and it must combine with the
-dye, thus forming a sort of connecting link between the dye and the hair.
-It is not absolutely essential that the mordant be applied first, although
-this is the customary and commonest practise. There are three ways by
-which the mordants can be fixed on the fur hair: First, by the absorption
-of the metallic oxide or hydroxide from a solution of the mordant prior to
-the dyeing; second, the mordant may be fixed on the fibre at the same time
-as the dye; and third, the mordant may be applied after the fur has been
-treated with the dye. The last two methods will be discussed in connection
-with the dyes, as they are special cases.
-
-The salts of metals which are comparatively easily dissociated in water,
-with the formation of insoluble oxides or hydroxides, are most applicable
-as mordants for furs, and among them are compounds of aluminum, iron,
-chromium, copper and tin. The constituents of the hair seem to bring
-about the dissociation of the metallic salt, and the oxide or hydroxide
-as the case may be, is absorbed and firmly fixed by the hair. Just what
-the manner and nature of this fixation are, is still uncertain. It is
-supposed that chemical combination takes place between the hair and the
-metal. The course of this process may, as far as is known, be described
-as follows, taking, for example, the case of chromium sulphate: In dilute
-solution, this compound gradually dissociates first into its basic salts,
-and finally into the hydroxide, the breaking up of the neutral salt being
-induced by the presence of the fur-hair.
-
-  Cr{2}(SO{4}){3} + 2H{2}O = Cr{2}(SO{4}){2}(OH){2} + H{2}SO{4}
-     chromium        water         first basic        sulphuric
-     sulphate                      chrome salt          acid
-
-  Cr{2}(SO{4}){2}(OH){2} + 2H{2}O = Cr{2}(SO{4})(OH){4} + H{2}SO{4}
-                                       second basic
-                                        chrome salt
-
-  Cr{2}(SO{4})(OH){4} + 2H{2}O = Cr{2}(OH){6} + H{2}SO{4}
-                                   chromium
-                                   hydroxide
-
-These reactions take place within the fibre, after the hair has been
-impregnated with the solution of the neutral salt, and when the compound
-has been rendered completely basic, in other words has reached the form of
-the hydroxide, it is supposed to combine with the acid groups contained
-in the hair substance, forming thus some complex, insoluble organic
-compound of the metal within the hair. According to some authorities the
-mordant is supposed to be present in the hair simply as the hydroxide,
-being tenaciously held by some physical means. The facts seem to indicate,
-however, that the metal is actually combined in some chemical way with the
-hair. For, if the mordant were present as hydroxide, then on white hair it
-would show the color of the hydroxide, which it does not. The same facts
-obtain with regard to other metals.
-
-In order for the hair to be properly mordanted, it is necessary that
-the metallic compound which is taken up by the hair be held in such a
-manner that the mordant cannot be removed by water or even dilute acids
-or alkalies. Salts which dissociate too readily produce mordants which
-are only superficially precipitated on the hair and subsequently come
-off. Usually some substance is added to the solution of the salt to
-cause slower and more even dissociation of the salt, so that the hair
-substance can be quite saturated with the metallic compound before any
-insoluble precipitate is formed. Dilute sulphuric acid, organic acids like
-acetic and lactic, and cream of tartar are used to facilitate the uniform
-absorption of the mordant salt by the hair.
-
-When the skins are mordanted before dyeing, they are immersed for 6 to
-24 hours in a solution containing 1 to 20 grams of the metallic salts per
-liter of water, together with the corresponding quantity of the assistant
-chemical. The skins should be so entered into the mordant solution that
-the hair is uniformly in contact with the solution, and all the skins
-so that they are acted upon alike. Machinery such as is used for killing
-is suitable for mordanting also. The duration of the mordanting, and the
-concentration of the solutions are varied according to the depth of shade
-required, and also according to the nature of the dye to be employed. By
-suitably combining several mordants a considerable range of colors can be
-obtained with a single dye.
-
-The various chemicals used as mordants are essentially the same no matter
-for which class of dyes they are used, there being only slight differences
-in the concentrations of the solutions, the manner of application of
-the mordants being practically the same. It is interesting to note that
-with the exception of chromium compounds, which are of comparatively
-recent adoption as mordants, all the chemicals now used for mordants
-were employed by the earliest masters of the art of fur dyeing. While
-some of the formulas used by those dyers display a lack of appreciation
-of the true action and function of the mordanting chemicals, yet it is
-quite remarkable that they chose, in spite of their limited knowledge of
-chemical processes and phenomena, just those materials which do act as
-mordants if properly applied. The most important metallic compounds for
-mordanting furs at the present time are salts of aluminum, iron (ferrous),
-copper, tin and chromium (as well as chromates and bichromates). The
-compounds of the metals with organic acids such as acetic acid are
-preferable, being more easily dissociated, and also leaving in solution
-an acid which is less injurious to the fur than a mineral acid. However,
-sulphates and other salts of the metals are also used extensively,
-inasmuch as they are cheaper than the organic salts.
-
-
-ALUMINUM MORDANTS
-
-Chief among the aluminum mordants are the various kinds of alum, which is
-a double sulphate of aluminum and an alkali such as sodium, potassium or
-ammonium. All these salts except that of sodium, form large, colorless,
-octahedral crystals, and are soluble in about 10 parts of cold water,
-and 1/4 part of hot water. Sodium alum is even more easily soluble, but
-on account of the difficulty of obtaining it in crystalline form, it
-is little used. The common commercial alum is the potassium aluminum
-sulphate.
-
-Recently, aluminum sulphate has to a large extent replaced alum for
-mordanting purposes, because it can be obtained very cheaply in pure form,
-and it contains a greater amount of active aluminum compound than does
-alum. Only the iron-free salt, however, may be used for the needs of fur
-dyeing.
-
-Aluminum acetate also finds extensive application as a mordant in fur
-dyeing, and while somewhat more expensive than the alum or aluminum
-sulphate, it has the advantage over these compounds of being combined
-with an organic acid, which is preferable when the action on the hair and
-leather is considered. Aluminum acetate can be obtained in the market in
-the form of a solution of 10 degrees Beaume, but can also be prepared very
-easily as follows:
-
-   665 grams pure aluminum sulphate, or
-   948 grams potassium alum, are dissolved in
-     1 liter of hot water.
-  1137 grams of lead acetate (sugar of lead) are also dissolved in
-     1 liter of hot water.
-
-The two solutions are mixed, and thoroughly stirred. A heavy white
-precipitate forms, which is filtered off, and discarded after the solution
-has cooled. The aluminum acetate is contained in the filtrate, and the
-solution is brought to a density of 10 degrees Beaume by the addition of
-water, if necessary, and is preserved for use in this form.
-
-
-IRON MORDANTS
-
-Ferrous sulphate, iron vitriol, or copperas, as it is commonly known,
-forms pale green crystals, which on exposure to air lose water, and
-crumble down to a white powder. It is very soluble in both cold and
-hot water, but the solutions oxidize very rapidly, turning yellowish,
-and should therefore be used immediately. Care must be taken that a
-good quality of iron vitriol be used for the mordant, otherwise very
-unsatisfactory results will be obtained.
-
-Ferrous acetate is prepared in a manner similar to the aluminum acetate,
-and is occasionally employed instead of the ferrous sulphate. Inasmuch,
-however, as the solution of ferrous acetate is very easily oxidizable
-when exposed to the air, a more stable form is used, and this comes on
-the market as iron pyrolignite or iron liquor. This can be prepared by
-dissolving iron in crude acetic or pyroligneous acid, or by treating a
-solution of iron sulphate with calcium pyrolignite. Iron liquor is really
-a solution of ferrous acetate that contains certain organic impurities
-which prevent, or rather, considerably retard the oxidation of the iron
-salt, but which in no way interfere with its mordanting properties. The
-commercial product can be had in various concentrations, but 10 degrees
-Beaume is the most usual and most convenient.
-
-
-COPPER MORDANTS
-
-The most important copper salts used in fur dyeing processes are copper
-sulphate, or blue vitriol, occurring in large blue crystals, very soluble
-in cold and in hot water; and copper acetate, which is formed by treating
-a solution of copper sulphate with a solution of the requisite quantity
-of lead acetate. Copper acetate can also be obtained in the form of
-blue-green crystals, very soluble in water, the solution becoming turbid
-on prolonged heating, due to the formation of a greenish basic copper
-acetate. This insoluble compound is known commonly as verdigris, although
-it is not usually produced in the manner mentioned. Numerous fur dyeing
-formulas contain verdigris, but inasmuch as the basic copper acetate is
-insoluble and thus incapable of reacting with any of the substances used
-in dyeing, it is assumed that the soluble normal copper acetate was meant,
-for this compound is also sometimes called verdigris.
-
-In addition, there must be mentioned here a compound which formerly found
-extensive use in fur dyeing. This is a double salt of copper and iron,
-analogous to alum, ferrous copper sulphate, known as blue salt. It is very
-seldom used at the present time, being more effectively replaced by other
-substances.
-
-
-CHROMIUM MORDANTS
-
-The typical chromium mordant is chrome alum, which is a potassium or
-ammonium chromium sulphate, constituted just like the aluminum alums, and
-forming crystals like these. More frequently used, nevertheless, than the
-chrome alum, is chromium acetate, which is prepared from it, either by
-treating a solution of the chrome alum with a solution of lead acetate,
-or in the following manner:
-
-   50 grams of chrome alum are dissolved in
-  500 cubic centimeters of boiling water. To this is added
-   15 grams of 20% ammonia, diluted with 15 grams of water.
-
-The precipitate which forms is filtered off, and preserved, the filtrate
-being discarded. After thoroughly washing the residue on the filter it is
-dissolved in dilute acetic acid, heating if necessary, to effect solution.
-
-Other chromium compounds of an entirely different type are also used in
-fur dyeing, these being chromates and bichromates, the latter finding
-greater application than the former. Sodium bichromate is the salt most
-usually employed. This forms orange-red crystals which are very soluble
-in water, and in addition to its use as a mordant it also serves as an
-oxidizing agent for developing or fixing certain dyes on furs.
-
-
-TIN MORDANTS
-
-Compounds of tin find only limited application in fur-dyeing, the only one
-of importance being tin salts, stannous chloride, which occurs in the form
-of white, hygroscopic crystals, which must be preserved in closed vessels.
-It is very soluble, but in dilute solutions it readily forms a basic salt,
-so stannous chloride is usually used in very concentrated solutions.
-
-
-ALKALINE MORDANTS
-
-After the furs have been treated with the solution of some alkali for the
-purpose of killing the hair, they are always passed through a slightly
-acidulated bath to remove any alkali which may still be adhering. This
-operation must always be gone through before the skins can be mordanted
-or dyed, for if it were neglected, very uneven and uncertain results
-would be obtained. This process, however, entails the expenditure of
-no small amount of time, labor and chemicals when large lots of skins
-are being handled. In order to eliminate this extra step of "souring"
-between killing and mordanting or dyeing, it has been proposed to use
-alkaline mordants which combine the killing and mordanting functions,
-and accomplish these two processes at the same time. The advantages of
-employing such mordants are easily apparent. Cumbersome manipulation and
-handling of the skins, with the attendant consumption of much time and
-labor are reduced to a minimum, and besides there is no needless waste of
-chemicals as is the case in the ordinary methods of killing the furs.
-
-The principle of alkaline mordants is not a strictly new one. If it
-be remembered that the old killing formulas used by the fur dyers of
-an earlier age, contained metallic salts with mordanting properties in
-addition to the alkaline substances, which alone were effective as killing
-agents, it would seem that the suggested alkaline mordants were merely a
-revival in modified form of the old processes. This is undoubtedly true
-in a large measure, for the killing mixtures which the old masters used
-certainly embodied the fundamental principle of simultaneous killing and
-mordanting, although it was not recognized at that time.
-
-Modern alkaline mordants have therefore been devised which can be employed
-for killing and mordanting furs at the same time. They are prepared as
-follows:
-
-
-ALKALINE ALUMINUM MORDANT
-
-  250 grams of potassium alum are dissolved in
-    1 liter of boiling water. To this solution is added
-  300 grams of soda ash, previously dissolved in
-  750 c.c. of water, and the resulting precipitate is filtered off,
-      washed and pressed, and then dissolved in a solution of 65 grams
-      of caustic soda in 1 liter of water.
-
-
-ALKALINE CHROMIUM MORDANT
-
-  250 c.c. of chrome acetate mordant of 20 degrees Beaume
-  320 c.c. of caustic soda solution of 38 degrees Beaume (32.5%)
-   10 c.c. of glycerine 30 degrees Beaume (95%)
-
-The solution of these substances is brought up to a volume of 1 liter by
-the addition of 420 c.c. of water.
-
-
-ALKALINE IRON MORDANT
-
-   138 grams ferrous sulphate are dissolved in
-   362 c.c. of warm water. Cool and add
-    25 c.c. of glycerine. Then slowly and carefully add
-  25.5 c.c. of concentrated ammonia, taking care that no precipitate
-       forms.
-
-While these alkaline mordants seem to have much in their favor, there
-are certain possible objectionable features which must be considered.
-The solutions of the mordants are generally very alkaline, and not every
-fur can withstand more than a limited quantity of alkaline substance
-for longer than a comparatively short time. Suitable mordanting usually
-requires a longer time than killing does, so with the use of the alkaline
-mordant, if the skins remain in the solution until sufficiently killed,
-they may be insufficiently mordanted, while if the furs are treated long
-enough to be properly mordanted, the hair may have been over-killed.
-However, the idea of the alkaline mordant is a good one, and it is
-only a matter of time and patient, scientific experimentation when the
-difficulties of the method will be eliminated, and a much-desired process
-will become a practical realization.
-
-The general methods for applying the various mordants of all sorts follow
-closely the procedure adopted for the killing formulas, and similar
-precautions must be observed, in order to obtain consistently uniform
-results. With the exercise of care, there is little reason for the
-mordanting operations to go wrong.
-
-After proper treatment of the skins in the mordants, they are removed and
-drained off, then rinsed lightly in running water to remove the excess
-of mordant liquor, after which they can be directly entered into the
-dye bath. If it is not feasible to dye the mordanted skins at once, as
-is often the case, the skins are kept moist, and under no circumstances
-allowed to dry.
-
-
-
-
-CHAPTER XII
-
-FUR DYEING
-
-MINERAL COLORS USED ON FURS
-
-
-Before the introduction of the fur dyes now used, certain inorganic
-chemical substances were employed in addition to the vegetable dyes,
-for the production of colors on furs. Even to this day such materials
-are used to obtain certain effects in special instances. The idea of
-employing mineral chemicals undoubtedly originated in the textile-dyeing
-industry, which at one time was dependent to an appreciable extent on
-mineral substances for the production of certain fast shades. Compounds
-of iron, lead, manganese, also of copper, cobalt and nickel were all used
-for dyeing, either singly or in various combinations. In the application
-on furs, the brush method was the only one practicable, as the skins would
-have been ruined by dipping them into solutions of these chemicals in the
-concentrations necessary for dyeing.
-
-The dyeing of furs with mineral colors involves the precipitation on
-the fibre in a more or less permanent form of the sulphide, oxide or
-other insoluble compound of a metal, and can be brought about in several
-ways. By what is known as double decomposition, that is, by the use
-of two solutions successively applied, the ingredient of one causing a
-precipitate to form when in contact with the constituent of the second,
-the color is produced on the hair. Another method is to use solutions of
-chemicals which decompose on contact with the hair, forming an insoluble
-compound. In the first method the hair is alternately treated with the
-two solutions of the requisite chemicals, drying between each brushing,
-the process being repeated until the desired shade is obtained. The second
-method merely requires the solution of the chemical to be applied to the
-hair, which is then dried, the color forming by itself.
-
-One of the most important of the mineral dyes, and which is occasionally
-used to this day, is lead sulphide, formed by the double decomposition
-method by precipitating a soluble lead salt with ammonium sulphide, or any
-other alkaline sulphide. By simply brushing an aqueous solution of lead
-acetate, also known as sugar of lead, on a white fur such as white hare or
-rabbit, a light, brownish coloration is obtained due to the combination of
-the lead with the sulphur of the hair. If the lead solution is carefully
-applied several times on this type of fur, until a sufficiently dark
-color is produced, it is possible to get a fairly good imitation of the
-stone marten. The brown color is very fast, being actually formed within
-the hair. In most cases, however, for dyeing lead sulphide shades it is
-necessary to use the two solutions. Thus the pale greyish or slightly
-brownish-grey shades of the lynx can be reproduced on white rabbit or
-hare by this process. A solution containing 60 grams of lead acetate per
-liter of water is brushed on to the hair of the fur which has previously
-been killed in the usual manner, and the hair is then dried. A solution
-of 50 grams of ammonium sulphide per liter of water is next brushed on,
-and the fur again dried. Care must be exercised in handling the ammonium
-sulphide as it is a very malodorous liquid, the fumes of which are
-poisonous when inhaled. The alternate brushings are repeated until the
-desired depth of shade is obtained. A very dark brown, approaching a black
-can be obtained in this way. This color can be used for the production of
-certain attractive effects. By brushing over the tips of the hair, which
-has previously been dyed a dark brown by means of the lead sulphide color,
-with a dilute solution of hydrochloric acid, or with peroxide of hydrogen,
-the hair will become white in the parts so treated, due to the formation
-of lead chloride or lead sulphate, respectively. Thus white tipped furs
-can be obtained, but the process is applicable only when the furs have
-been dyed by the lead sulphide method.
-
-Potassium permanganate is occasionally used to produce dyeings of a
-brown shade on furs. Considerable care has to be taken in applying this
-substance, as it is possible to affect the hair. The strength of the
-solution must be varied according as the hair to be dyed is weak or
-strong. A cold solution of 10 to 20 grams of potassium permanganate per
-liter of water is brushed on to the hair, which is then dried. A brown
-precipitate of manganese is formed on the hair after a short time, and
-the process is repeated until the required shade is obtained. For furs
-with harder hair, stronger solutions can be used. The dyeing is very
-fast, but it is seldom used, cheaper and better shades being obtained in
-other ways. Spotted white effects can be produced on the brown dyeing with
-permanganate of potash by applying a solution of sodium bisulphite, the
-brown color being dissolved by this chemical.
-
-The compounds of other metals, such as iron, copper, cobalt and nickel
-are not used in practise as the dyeings are not fast, and can be better
-produced in other ways.
-
-
-
-
-CHAPTER XIII
-
-FUR DYEING
-
-VEGETABLE DYES
-
-
-With the exception of the few shades which could be produced solely by
-means of coloring matters of a chemical character, all dyeings on furs up
-to about thirty years ago were made with dye substances obtained from the
-vegetable kingdom, either alone, or in conjunction with the aforementioned
-mineral colors. The colors of vegetable origin used in comparatively
-recent times were mainly extracts of the wood of certain trees; so the
-name "wood dyes" has come to be applied generally to the dyes of this
-class. The use of the vegetable or natural dyes on furs dates back to
-quite ancient times, as frequent allusions and descriptions in Biblical
-and other contemporaneous literature testify. There are numerous pictures
-on monuments and tablets illustrating the dyeing of furs among the ancient
-Egyptians, the evidence indicating that the juice of certain berries, and
-extracts of certain leaves were used for the purpose. At a later period,
-in the Roman era, henna, which was used over two thousand years ago as
-to-day for the beautification of the hair of women, was also used to
-color fur skins. The instances cited here are merely of scientific and
-historical interest, and are not of practical importance as far as fur
-dyeing methods are concerned.
-
-It was not until many centuries later that the dyeing of furs took on
-the aspects of a commercial art, and the substances then employed were
-chiefly tannin-containing materials such as gall-nuts and sumach, which
-in conjunction with certain metallic salts, particularly those of iron,
-were capable of producing dark shades. The use of iron compounds to form
-dark grey or black colors on leather tanned by means of the tannins, had
-been common for a long time, and it was natural that fur dyers should
-try to produce such shades on furs in a similar fashion. The use of the
-iron-tannin compound as a dye proved to be very effective, and to this day
-the production of blacks by means of the vegetable coloring matters has as
-a basis an iron-tannate. A formula in common use in the latter seventeenth
-and the eighteenth centuries for producing black shades on furs, is the
-following:
-
-  Lime water                1117 parts
-  Gall-nuts                 1500   "
-  Litharge                   500   "
-  Salammoniac                 65   "
-  Alum                       128   "
-  Verdigris                   64   "
-  Antimony                    64   "
-  Minium                      32   "
-  Iron filings               128   "
-  Green copperas             384   "
-
-All these substances except the gall-nuts, the copperas and half the lime
-water were boiled up in a cauldron; then the gall-nuts and the copperas
-were placed in a bucket and the contents of the cauldron poured in, and
-the rest of the lime water added. The mixture was stirred up, allowed to
-settle for an hour, and when cool, was ready to be applied by the brush
-method. For dyeing by the dip process, a similar mixture was used, only
-considerably diluted with water. A study of the formula discloses the
-fact that in it are combined killing and mordanting substances as well
-as dyeing materials. The lime water, in conjunction with the salammoniac
-serves as a killing agent, the verdigris, copperas and alum are mordants,
-while the litharge and the minium, both compounds of lead, could possibly
-act as mineral dyes, and the iron filings and the antimony took virtually
-no part at all in the dyeing, except, perhaps to act in a mechanical way.
-
-The formulas for other shades were made up along similar lines, the chief
-constituent of vegetable nature being either gall-nuts, sumach, or both.
-A mixture for a chestnut brown, for example, contained gall-nuts, sumach,
-and the various other mineral constituents as in the black dye, litharge,
-alum, copperas, verdigris, salammoniac, antimony, and in addition, red
-lead and white lead. It is evident in both these instances that the shade
-obtained was as much the result of mineral dyeing as of vegetable dyeing.
-
-The discovery of America introduced into Europe many new dye substances,
-chiefly wood extracts such as logwood and Brazilwood, but it was not until
-the nineteenth century that these materials found their way into the
-dye formulas of the fur dyer. Most of the processes used in the dyeing
-of furs were adaptations of methods employed in silk dyeing, the silk
-fibre being considered as most nearly approaching fur-hair in nature and
-characteristics. By devious and circuitous paths the formulas of the silk
-dyers reached the fur people, and so, in the middle of the nineteenth
-century, dye mixtures containing the various dyewoods as well as the
-tannin-containing substances were in general use for the dyeing of furs.
-The following is a typical recipe of that time for the production of black
-on furs like wolf, skunk, raccoon, etc.:
-
-  Roasted gall-nuts         1000 parts
-  Sumach                     200   "
-  Iron mordant               200   "
-  Copper vitriol             100   "
-  Litharge                    80   "
-  Alum                        60   "
-  Salammoniac                 50   "
-  Crystallized verdigris      40   "
-  French logwood extract      30   "
-  Rain water                7000   "
-
-The mixture was boiled up, and after cooling was ready for application by
-the brush method, the skins being first killed by a killing mixture also
-applied by the brush. The dye substances in this case are the gall-nuts,
-sumach and the logwood extract, with the iron mordant, copper vitriol, and
-alum as mordants. For brown shades a similar formula was used containing
-Pernambuco wood extract, logwood extract, quercitron bark, gall-nuts and
-dragonblood, together with iron, copper and alum mordants.
-
-Formulas such as the above were mainly empirical, that is, they
-were compounded as a result of trial of various combinations of the
-constituents, without considering the nature and quantitative character
-of the reactions, as long as the desired shades could be obtained. Such
-dye mixtures were frequently found to yield results varying from those
-expected or originally obtained, because the effectiveness of the formulas
-depended upon the exact duplication in every detail, of conditions which
-had given satisfactory results previously, and it was not always possible
-to attain such an accurate reproduction of circumstances, especially
-when the fur dyers were quite ignorant of the scientific relationships
-of the materials used. So when more light had been shed on the nature
-and chemical characteristics of the vegetable dye substances, formulas
-like those described were no longer employed, although the essential
-ingredients were the same in the new processes. Unnecessary constituents
-were eliminated, and proper ones substituted where it was required, and
-the quantities of the materials used were made to conform to the chemical
-laws governing the reactions. Since these new formulas were based on a
-rational understanding of the constituents and their reactions, it is
-desirable to study the latter briefly, before further discussing the
-formulas themselves.
-
-The substances of vegetable origin used in modern fur dyeing may be
-grouped into two classes, one, the tannin-containing materials, and
-the other, the dyewoods proper. The most important of the tannins are
-gall-nuts, sumach and chestnut extract. Cutch, which also comes under
-this class, is more frequently used for the production of brown shades,
-so it is grouped with the dyewoods. Among the latter are logwood, fustic,
-Brazilwood, quercitron, turmeric, and several others of less significance.
-
-
-1. _Tannin Materials_
-
-First and foremost under this heading are the nutgalls. These are
-ball-shaped excrescences produced on certain plants by the punctures
-of insects in depositing their eggs. There are two chief varieties, the
-European, and the Chinese. The European galls are formed by the female
-gall-wasp which drops an egg in the rind of young branches of certain
-oaks. A swelling (the nutgall) is produced, in which the young insect
-develops, and from which it finally escapes by piercing a hole through
-the shell. Those galls which are not pierced have a fresh bluish or green
-color, are heavy and contain most tannic acid. After the insect has gone
-out, the galls are of a lighter, yellowish color, and also of inferior
-quality. The best oak-galls are the Aleppo, and the Turkish or Levant
-galls, containing 55-60% of tannic acid, and about 4% of gallic acid. The
-Chinese galls are produced by the puncture of a plant-louse on the leaves
-and leaf-stalks of a species of sumach, and not on oaks. The galls are
-very light, and very rich in tannic acid, containing often as much as 80%.
-For dyeing purposes, nutgalls are usually ground to a powder, and in some
-instances they are even roasted first and then ground.
-
-Sumach consists of the leaves and sometimes of the small twigs and stems
-of a species of sumach plant known as the Rhus coriaria. The Sicilian
-variety is the finest commercial quality, with the Virginian ranking next.
-It is sold as a powder, but also in the form of the whole or crushed
-leaves. The best sumach contains 15-25% of tannin. Extracts are also
-manufactured, a liquid extract of 52 degrees Twaddell, which forms a dark
-brown, thick paste; and a solid extract, formed by evaporating the liquid
-extract to dryness.
-
-Chestnut extract is prepared from the wood of the chestnut oak, which
-contains 8-10% of tannin. The solid extract has a bright, black color,
-while the liquid extract is a dark brown paste with a smell like that of
-burnt sugar.
-
-The tannins all give greyish to black shades with iron salts, and it is
-this fact which renders them important for fur dyeing.
-
-
-2. _Wood dyes_
-
-One of the most important of all the natural dye substances, especially
-for the production of blacks, is logwood. The color is really a red, but
-with the common mordants it forms blue, violet or black shades. Logwood,
-or campeachy wood, as it is sometimes called, is the product of a large
-tree growing in the West Indies, and Central and South America. When
-freshly cut, the wood is practically without color, but when exposed to
-the air it soon becomes a dark reddish-brown on the surface. The coloring
-principle of logwood is called hematoxylin, which is a colorless substance
-when pure, and is of itself incapable of dyeing; but when it is exposed
-to the air, especially when moist and in the presence of some alkaline
-substance, it is converted into hematein, which is the real coloring
-matter of logwood. To prepare the wood for use, the logs are chipped or
-rasped, the chips being heaped up and moistened with water. Fermentation
-occurs, and the heaps are frequently turned to allow free access of air to
-the wood, and to prevent overheating. As a result of this process, a great
-part of the hematoxylin is converted to the hematein. The logwood may
-be used for dyeing in this state as chips, but logwood extracts can now
-be obtained of a high degree of purity and are easier to work with. The
-commercial forms of the extract, are the liquid of 51 degrees Twaddell,
-and the solid extract. Hematein crystals can also be obtained. All these
-extracts contain mainly hematein, together with a small percentage of
-hematoxylin which is converted to the former during the dyeing process.
-Logwood is never used as a direct dye, but is used to form color lakes
-with the various mordants, the following colors being produced:
-
-  Iron mordants give grey to black shades
-  Copper mordants give green-blue to black shades
-  Chrome mordants give blue to black shades
-  Aluminum mordants give violet shades
-  Tin mordants give purple shades
-
-By combining several of the mordants, any desired shade of black can be
-obtained, and if other dyewoods are used in conjunction with the logwood,
-the range can be further increased.
-
-Fustic, yellow-wood, or Cuba wood, as it is variously called, is obtained
-from a tree also growing in the West Indies, Central and South America.
-It is used either as wood chips, or as a paste extract of 51 degrees
-Twaddell, and occasionally as solid extract. Fustic contains two coloring
-matters, morintannic acid, possessing the characteristics of a tannin, and
-which is quite soluble in water, and morin, which is rather insoluble, and
-which settles out from the liquid extract. Fustic is the most important of
-the yellow dyes of natural origin, and is used considerably in fur dyeing
-with logwood for shading the blacks, or for producing compound shades.
-With the usual mordants fustic gives the following colors:
-
-  With iron salts           dark olive
-  With copper salts         olive
-  With chrome salts         olive-yellow to brownish-yellow
-  With aluminum salts       yellow
-  With tin salts            bright yellow to orange-yellow
-
-Brazilwood, or redwood, is the product of a tree found in Brazil, and
-exists in several varieties, such as peach wood, Sapan wood, Lima wood,
-and Pernambuco wood. They all yield similar shades with the various
-mordants, and all seem to contain the same coloring principle, brasilin,
-which, like the hematoxylin, has no dyeing power, but by fermentation and
-oxidation it is converted to brasilein, corresponding to the formation
-of hematein. Brazilwood and the related woods are used either as chips or
-extract, but seldom alone, usually in conjunction with other dyewoods. By
-combining logwood, fustic and Brazilwood in various proportions, and by
-employing suitable mordants, all the shades required by the fur dyer can
-easily be produced.
-
-Quercitron is the inner bark of a species of oak (Quercus tinctoria) found
-in the United States. It contains two coloring principles, quercetrin and
-quercetin. The fresh decoction of quercitron bark is a transparent dull
-orange-red which soon becomes turbid and deposits a yellow crystalline
-mass. It is generally used in conjunction with other dyes.
-
-Cutch is the dried extract obtained from a species of acacia, the
-principal varieties being Bombay, Bengal, and Gambier cutch. It contains
-two coloring principles, catechin and catechu-tannic acid. Cutch acts as
-a tannin, and like other tannins discussed above, can be used for the
-production of grey or black shades with iron mordants. It is employed
-chiefly, however, for dyeing browns. Aluminum salts give with cutch
-a yellowish-brown, tin salts give a lighter yellow, copperas gives a
-brownish-grey, and chrome and copper salts give brown shades.
-
-Turmeric is the underground stem of the Curcuma tinctoria, the coloring
-principle being called curcumin. It may be used as a direct dye, but
-usually a mordant is used. Turmeric is sometimes used in place of fustic.
-
-While the tannins can be used alone with an iron mordant for producing
-greyish to black shades, the dyewoods alone yield colors which would be
-too bright to be suitable for dyeing furs. In order to tone down this
-brightness, and to give to the dyeings that greyish undertone which is
-characteristic of the natural furs, and which can only be imitated by
-means of the iron-tannin compound, it is customary to combine the tannins
-with the wood dyes. The iron-tannate constitutes the foundation of the
-color which gets its intensity, and necessary brilliancy and bloom from
-the wood dyes. Moreover, the presence of the iron-tannin compound helps
-considerably to increase the fastness of the dyeing. Furs dyed with the
-combination of the tannins and the wood dyes obtain an additional tanning
-treatment which materially improves the quality of the leather, for not
-only do the tannin substances exert this tanning action, but the dyewoods
-as well, for they are themselves either of the nature of tannins, or
-contain a coloring principle which is a tannin. It is to the combined
-effects of the tannin substances and the dyewoods that furs dyed with
-vegetable dyes owe their beauty of color, lustre, naturalness of shade,
-permanence of the dyeing, and durability of the leather. Wood dyeings
-on furs have for this reason acquired a just renown, but owing to the
-introduction of the new kinds of fur dyes, the use of the vegetable dye
-substances has been greatly reduced.
-
-The dyes of vegetable origin can be applied to furs by either the brush
-method or the dip method, or both, and since mordants are required
-with the dyes of this class, they are applied in one of the three ways
-mentioned in a previous chapter: first, by mordanting before dyeing;
-second, by applying mordant and dye simultaneously; and third, by
-mordanting after the skins have been treated with the dye.
-
-
-I. DYEING WITH VEGETABLE DYES BY THE BRUSH METHOD
-
-The use of the brush method in applying the natural dyes to furs is
-limited to a comparatively few kinds of dyeing, namely to produce
-special effects on furs, or to give to the upper-hair of furs a coat
-of dye different from the base color. In a quite recent German patent
-is described a process for blending a red fox as a silver fox and
-the procedure affords a good example of brush dyeing with preliminary
-mordanting. The specification is as follows: "D. R. P. 310, 425 (1918).
-A process for dyeing red fox as silver fox. The tanned and dressed skin
-is first superficially decolorized by applying a dilute mixture of milk
-of lime, iron vitriol and alum, with a soft brush so as only to penetrate
-the top-hair. Allow to remain for 4-6 hours, dry, and beat out the dust.
-A dilute solution of iron vitriol is brushed on so as only to wet the
-top-hair, and the skin is thus allowed to remain moist for 12-24 hours.
-Then without drying, a solution of iron vitriol, salammoniac, litharge,
-red argol and wood ashes is brushed on cold with a hard brush so as
-to penetrate all the hair down to very near the skin. The skin has now
-completely lost its red color, and has become a pale yellow. It is now
-ready to be dyed. An infusion of roasted nutgalls, which have been boiled
-for 3-4 hours with water, is applied cold with a soft brush to the upper
-hair. Allow to remain so for 2-3 hours, and without drying, apply a weaker
-solution of the roasted nutgalls with a hard brush so as to saturate the
-hair thoroughly. Dry and beat out. According to the concentration of the
-solution applied, the hair will be colored blue-grey to black, and the
-shade can be varied by varying the strength of the solutions used. The
-different parts of the skin, or those parts of different shades can be
-dyed accordingly."
-
-In this patent all the operations, including killing, mordanting and
-dyeing are done by the brush method, and the process, from this point
-of view is quite similar to one which might have been employed a century
-previous. It is evident that the time and effort required to carry out the
-details as described in the patent would only be warranted in exceptional
-cases, where the value of the dyed fur would be considerably greater than
-that of the natural skin.
-
-An example of the application at the same time of dye and mordant by the
-brush method is the original French Seal dye, which is still employed to
-a limited extent to produce a brilliant, deep, lustrous black topping on
-furs which have already been dyed by the dip process. A typical formula
-for the old French Seal dye is the following:
-
-  Green copperas             10 parts
-  Alum                       10   "
-  Verdigris                  10   "
-  Gall-nuts                  80   "
-  Logwood extract
-    (15 degrees Twaddell)   150   "
-  Water                    1000   "
-
-This mixture is applied to the top of the hair of the furs, after previous
-killing, and the skins allowed to remain moist for several hours, and
-also exposed to the air. The skins are then dried, and beaten out, and if
-necessary a second coat of dye is brushed on. In dyeing seal-imitation
-on muskrat, or skunk-imitation on opossum, for example, the black color
-required on the top-hair, or the upper part of the hair when the furs are
-sheared, can be produced by applying a mixture similar to the above, to
-the furs after they have received their base color by the dip process with
-natural dyes or with the Oxidation Colors. Occasionally, the dyeing is
-given an after-treatment with a dilute solution of sodium bichromate to
-help develop the color, the action in this case being that of an oxidizing
-agent, and not of a mordant.
-
-As far as the third method of mordanting is concerned, that of first
-applying the dye, and then the mordant, it is rarely practised with
-the brush method. The procedure, however, consists in first brushing
-on a solution of the desired dye, then drying and brushing on a mordant
-solution. These operations are repeated perhaps two or three times until
-the proper shade is obtained, exposing the furs to the air for the color
-to be developed.
-
-
-II. DYEING WITH VEGETABLE DYES BY THE DIP METHOD
-
-It was in the application to furs by the dip process that the use of the
-vegetable dyes attained great importance, and although at the present
-time, natural organic dyes have largely been superseded by the Oxidation
-Colors and Aniline Black dyes, yet for certain purposes, and especially
-for the production of blacks, the wood dyes still are able to hold their
-own.
-
-The dyeing of black formerly constituted probably the most important
-branch of the fur dyeing industry, and was undoubtedly the most difficult
-one. For it is possible to obtain as many different kinds of black
-as there are dyers of this color, but only a few certain shades are
-desirable. The division of the classes of furs into those derived from
-the various kinds of sheep, and those obtained from other animals is
-particularly marked in the dyeing of black, and both the composition of
-the dye formulas and the methods of dyeing are somewhat different for
-the two groups. For the dyeing of black on Persian lambs, broadtails,
-caraculs, etc., a combination of logwood and nutgalls with the requisite
-mordants is used, while on hares, Chinese sheep, foxes, raccoons, opossum,
-etc., a mixture of logwood and turmeric or fustic, with the proper
-mordants is used.
-
-The general procedure is as follows: The dye substances to be used are
-ground up to a powder in a mill constructed for the purpose, after which
-they are boiled with water in a copper-lined kettle or cauldron, heated
-from the outside by steam. The customary arrangement is to have a jacketed
-kettle, supported on a stand, and having taps and valves to enable the
-liquor to be drawn off, or pivoted, so that the kettle can be tilted,
-and the contents poured out. The use of the copper-lined vessel is to be
-preferred, as it is unaffected by any of the dye substances, and so cannot
-cause any rust stains. After the dyes have gone into solution and have
-cooled, the mordant chemicals, previously dissolved in water, are added,
-and the mixture stirred up. The dyeing in this instance is effected by the
-simultaneous application of dye and mordant. The dye mixture is now run
-off, or poured out in the proper quantity into a number of small vats of
-25-30 gallon capacity, or into a paddle vat, which can be closed, while
-the paddle is rotating. The latter device is to be preferred because it
-permits the dye to retain its temperature better and for a longer period
-of time, but when lambs are being dyed only the open vats are used. The
-temperature of the dye mixture is between 40 deg. and 45 deg. C., for only at
-this temperature can the hair absorb the dye properly without injuring the
-leather. The killed skins are immersed in the dyebath for a time, usually
-overnight, after which they are removed, drained and hung up, with the
-hair-side exposed to the air, so as to permit the dye to develop, which
-takes place with the aid of the atmospheric oxygen. The dyebath is again
-brought to the proper temperature, and the skins are again entered, to go
-through the same process as often as is necessary to obtain the desired
-depth of shade. The dyed skins are thoroughly washed to remove excess dye,
-then dried and finished. The following are a few dye formulas used in the
-production of blacks:
-
-  Logwood extract       100 grams
-  Chestnut extract       14 c.c.
-  Turmeric               38 grams
-  Iron acetate 6 deg. Be.    50 c.c.
-  Water                1200 c.c.
-
-or,
-
-  Cutch                  15 grams
-  Soda                   14 grams
-  Logwood extract       120 grams
-  Verdigris              19 grams
-  Iron acetate 5 deg. Be.    16 c.c.
-  Water                1200 c.c.
-
-A recently published formula for dyeing China goat skins black, is the
-following:
-
-Dissolve 50 lbs. of dark turmeric and 45 lbs. of logwood extract and
-make up to 300 gallons of solution, at 95 deg. F. Enter the killed skins and
-leave them in the liquor until they rise to the surface. Then take them
-out and add 25 lbs. of logwood extract, 10 lbs. of sumach, 10 lbs. of
-blue vitriol, 5 lbs. of fustic extract, and about 60 lbs. of iron acetate
-liquor. Stir up well, and immerse the skins for 18 hours. Draw them up,
-and expose to the air for 12 hours. Heat the liquor again to 95 deg. F. and
-put the skins back for 12 hours. Draw out, hang up in the air for a time,
-then wash thoroughly, hydro-extract, dry and finish.
-
-In a German patent, D. R. P. 107,717 (1898), is described a method for
-dyeing lambs black, consisting in treating the skins for 24 hours in a
-logwood bath, then rinsing in cold water, and mordanting for 15 hours in
-a solution of bichromate of potash. The skins are then washed and treated
-with a solution of iron salt, then dried. This process, while of not much
-practical importance, is an illustration of mordanting subsequent to the
-dyeing treatment.
-
-As far as the production of other shades is concerned, the procedure is
-quite similar to the regular black method. For a dark brown, for example,
-the skins are dyed in a mixture containing
-
-  Gall-nuts                  40 parts
-  Verdigris                  10   "
-  Alum                       10   "
-  Copperas                    5   "
-  Brazilwood extract
-    (15 deg. Twaddell)          150   "
-  Water                    1000   "
-
-employing operations just as in the case of the black.
-
-Greyish-blue shades on white hares, lambs, kids, etc., can be obtained by
-treating the skins successively in the following baths:
-
-  1. Logwood extract  100 grams
-     Water              1 liter
-  2. Indigotine        10 grams
-     Alum              10 grams
-     Water              1 liter
-
-Bluish-grey tones on the same furs can be produced by treating with
-
-  1. Logwood extract  200 grams
-     Indigotine        15 grams
-     Water              1 liter
-  2. Alum             150 grams
-     Salammoniac       12 grams
-     Water              1 liter
-
-Similar grey shades can be produced by mordanting the skins with an iron
-salt, and then dyeing in a weak bath containing gall-nuts, sumach and iron
-vitriol. This method is very effective for making Alaska or silver fox
-imitations.
-
-
-
-
-CHAPTER XIV
-
-FUR DYEING
-
-ANILINE BLACK
-
-
-Fur seal for a long time has been a fur of distinction and importance in
-the fur industry, and consequently the dyeing of seal has constituted an
-important, though not very extensive branch of the art of fur dyeing.
-In quite recent times the popularity of seal has become so great that
-imitations have had to be produced to help supply the demand, and as a
-result, French seal, or seal-dyed rabbit, and the so-called Hudson seal,
-which is seal-dyed muskrat, have acquired a great vogue. Occasionally
-opossum, nutria and other furs are also used for the purpose of producing
-seal imitations. While the supply of real seals is relatively small, and
-the demand large, the production of seal imitations has assumed large
-proportions, and as a result, the dyeing of seal and its imitations or
-substitutes has come to be a great branch of the fur dyeing industry.
-
-During the past thirty years, the long and tedious processes of dyeing
-seal and seal imitations, involving the use of dyes of vegetable origin,
-have largely been superseded by what is known as the Aniline Black dye.
-It was the French who first worked out successfully the application of
-Aniline Black to furs, and the method has attained much importance and
-extensive use in the fur dyeing industry.
-
-Aniline Black is the name given to an insoluble black dyestuff produced
-by the oxidation of aniline in an acid medium. As a finished product it
-cannot be used in fur dyeing, but if the hair of the furs be impregnated
-with a suitable preparation of aniline and then treated with certain
-oxidizing agents, the color will be formed on the hair, being firmly
-fixed and giving a fast black, resistant to light, washing and rubbing.
-The basis of the dye, aniline, is an oily liquid, possessing a peculiar
-fishy odor, colorless when pure, but rapidly turning brown when exposed to
-the air. It is obtained from benzol, which is distilled from coal-tar, by
-treating with nitric acid, forming nitrobenzol, which when subjected to
-the action of reducing chemicals is converted into aniline. The process
-may be shown schematically as follows:
-
-Coal--coal-tar--benzol--nitrobenzol--aniline oil--Aniline Black. Aniline
-Black was by no means a new dye when the French succeeded in producing it
-on furs. It had been used for a long time previous on textiles, chiefly
-cotton. The history of the development of the Aniline Black process
-throws considerable light on its nature and constitution, and so presents
-many features of interest. As early as 1834, the chemist Runge observed
-the formation of a dark green color when heated aniline nitrate in the
-presence of cupric chloride. Fritsche, in 1840, noticed that when chromic
-acid was added to solutions of aniline salt, a dark green, and sometimes a
-blue-black precipitate was produced, and later the same chemist obtained
-a deep blue by the action of potassium chlorate on aniline salt. It is
-interesting to note that Perkin, in 1856, conducting similar experiments
-on the oxidation of aniline with chromic acid, obtained a blue-black
-product from which he extracted the first synthetic coal-tar dye, mauve.
-Thus far, all the experiments on the oxidation of aniline proved to be
-merely of scientific interest, but in 1862, Lightfoot patented a process
-for the practical application of colors formed by the oxidation of aniline
-on the fibre, a greenish shade being obtained by that method, to which the
-name emeraldine was given, and by subsequent treatment with bichromate
-of potash, the green was changed to a deep blue color. Since that time,
-the methods for producing and applying Aniline Black have been developed
-and improved, although all the processes were based on the principles
-incorporated in Lightfoot's original patent. However, it was not until the
-last decade of the nineteenth century that the dyeing of furs by means of
-the Aniline Black method was successfully attempted.
-
-A knowledge of the nature and the manner of the chemical changes which
-take place in the production of Aniline Black is a valuable aid in
-obtaining satisfactory results in practise; and although Aniline Black
-was extensively used before the true character of the reaction was
-understood, since the successful determination of the constitution of
-Aniline Black and the discovery of the real nature of the process by
-Green and his collaborators in 1913, the methods have been considerably
-improved and simplified, with correspondingly better results in dyeing.
-As a consequence, the methods of dyeing furs with Aniline Black have also
-become simpler and more efficient.
-
-A discussion of the chemical changes which occur in the Aniline Black
-process, is out of place here on account of the highly involved and
-complicated character of the reactions, to understand which requires a
-considerable knowledge of specialized organic chemistry. But the essential
-features of practical importance in the production of Aniline Black are
-the following: As already noted, one of the characteristic properties of
-aniline is its tendency to turn from a colorless to a dark-brown liquid in
-the presence of the air. This change is due, together with certain other
-causes, to an oxidation brought about by atmospheric oxygen. By employing
-oxidizing agents, this oxidation can be accelerated and carried further,
-and eventually the Aniline Black is obtained. Among the substances which
-may be used to bring about the conversion of aniline to the insoluble
-black dye are manganese dioxide, lead peroxide, hydrogen peroxide, chromic
-acid, ferric salts, potassium permanganate, chloric acid and chlorates
-in the presence of certain metallic salts, particularly those of vanadium
-and copper. Chlorates, especially sodium chlorate and potassium chlorate,
-are the most commonly employed oxidizing agents, bichromate of soda or
-of potash being used, in addition, to complete the oxidation. When using
-chlorates it is necessary to have present in the dye mixture a small
-quantity of a metallic salt, which, while not entering into the reaction
-itself, is nevertheless indispensable as an oxygen carrier. Vanadium
-compounds have proved to be the most effective for this purpose, and
-according to an authority, one part of vanadium salt is sufficient to
-cause the conversion of 270,000 parts of aniline to Aniline Black, the
-necessary amount of a chlorate being present of course. Salts of copper,
-cerium, and iron are also extensively used, but they are not quite so
-efficient as vanadium.
-
-The formation of the Aniline Black in practise takes place in three
-well-defined steps, which it is important to be able to recognize and
-distinguish in order to obtain the best results. The first stage of the
-oxidizing process produces what is called emeraldine, which in the acid
-medium of the aniline bath is of a dark green, while in the free state it
-is of a blue color. As the oxidation proceeds, the second stage develops,
-the emeraldine being converted to a compound called nigraniline. This in
-acid solution is blue, and the free base is a dark-blue, almost black.
-It was formerly considered that the nigraniline was the Aniline Black
-proper, and so when this stage of the oxidation was reached, the process
-was often interrupted and not carried to the limit. This can account for
-the fact that Aniline Black dyeings usually turned green after a short
-time. The reason for this is that nigraniline, when treated with weak
-reducing agents, as, for example, sulphurous acid, is at once changed
-to emeraldine, with its dark green color. Since there is usually a small
-amount of sulphurous acid in the air, especially in places where coal or
-gas is burned, an Aniline Black dyeing which has not been carried beyond
-the nigraniline stage will be reduced in time to the emeraldine, and cause
-the dyeing to become green. The last step in the oxidation changes the
-nigraniline into what is properly called the ungreenable Aniline Black.
-Weak reducing substances like sulphurous acid do not change this compound
-to emeraldine, and stronger reducing agents only convert it to a brownish
-compound, which changes back to the black when exposed to the air. It is
-quite evident that in order to obtain a black which will not change to
-green in time, the oxidation of the aniline must be carried to the last
-stage. By making tests during the dyeing of the furs, it can easily be
-determined whether the oxidation has proceeded far enough.
-
-In the dyeing of textiles with Aniline Black, it is customary to carry
-out the operation at comparatively high temperatures, approaching 100 deg.
-centigrade. With furs such temperatures are out of the question, so it is
-necessary to repeat the dyeing several times in order to obtain the proper
-depth of shade working in the cold. Only the brush method can be used in
-applying the Aniline Black dye to furs, on account of the strong acidity
-of the dye mixture, which would ruin the leather, if the dyeing were done
-in a bath. Indeed, great care must be exercised even by the brush method
-to avoid too great penetration of the dye liquid, otherwise the roots
-of the hair will be attacked, and the leather may be "burned" from the
-hair side. Furs dyed with Aniline Black are frequently after-dyed by the
-dip-process with logwood or some other similar dye, in order to add to
-the brilliancy of the dyeing. Combined with intensity of color, Aniline
-Black on furs is the only dye which will also give fast, lustrous shades,
-and leave the hair soft and smooth.
-
-There are several methods of applying Aniline Black on furs, the most
-important being
-
-  1. One-bath Aniline Black
-  2. Oxidation Aniline Black
-  3. Diphenyl Black
-  4. Aniline Black by Green's Process
-
-
-1. _One-bath Aniline Black_
-
-A typical formula for this method is the following given by Beltzer:
-
-  Aniline salt            10 kg.
-  Sodium chlorate        1.5 kg.
-  Copper sulphate        0.7 kg.
-  Vanadate of ammonia     10 gr.
-
-All these substances are dissolved hot in 50 liters of water, and allowed
-to cool, forming solution A. Aniline salt is aniline oil which has been
-neutralized with the exact quantity of hydrochloric acid to form the
-hydrochloride. It forms white or greyish crystalline lumps very easily
-soluble in water. The sodium chlorate is the oxidizing agent, and the
-copper sulphate and the vanadate of ammonia are the oxygen carriers.
-
-15 kg. of sodium bichromate are also dissolved in 50 liters of water,
-forming solution B. The bichromate is also an oxidizing agent and serves
-to complete the oxidation of the aniline to the black.
-
-Immediately before using, solutions A and B are mixed together, both being
-cool. In general practise it is customary to mix only small quantities
-at a time, as a considerable precipitate forms when the whole batch
-is mixed at once, the precipitate being so much waste dye substance.
-Usually a liter of A and a liter of B are mixed at a time, and the furs
-brushed with the mixture. The brushing must be varied according as the
-hair is hard and stiff, or soft and tender. The hair must be thoroughly
-impregnated in all directions, and the penetration must not be too deep
-to affect the leather. With experience and dexterity satisfactory results
-can easily be achieved. After the skins have been properly treated, they
-are dried at a temperature of about 35 degrees centigrade. When dry, they
-are returned to the dye bench, where they receive another application
-of the dye mixture, and are again dried. This operation may be repeated
-as often as six or seven times before a sufficiently intense black is
-obtained. Another way of producing the desired depth of shade with fewer
-applications is by using more concentrated dye mixtures. Each method
-has its disadvantages, the greater number of brushings requiring the
-expenditure of more time and labor, and the greater concentration of
-the bath resulting in a considerable loss of dye substance due to the
-formation of a large precipitate when the two solutions are mixed, and
-moreover, not all furs can be treated with concentrated mixtures. The best
-results with this method usually require the application of six coats of
-a mixture of moderate concentration.
-
-
-2. _Oxidation Aniline Black_
-
-In order to overcome the difficulty of employing very concentrated dye
-mixtures, or of making many applications of the dye, a method was devised
-whereby the two solutions of the previous process, instead of being mixed
-together, are applied successively to the hair of the furs, the following
-formula, also by Beltzer, being an example:
-
-  Aniline oil                     10 liters
-  Nitric acid 36 deg. Beaume, or
-  Hydrochloric acid 22 deg. Beaume    20 liters
-  Cold water                      20 liters
-
-This is solution A, and is merely a solution of aniline hydrochloride,
-or nitrate, depending on which acid has been used. Nitric acid, although
-more costly than the hydrochloric acid, is to be preferred, because it
-is an oxidizing acid, and so assists in the oxidation of the aniline, and
-besides, has a more beneficial effect on the hair than the hydrochloric,
-in the matter of softness and luster.
-
-  Sodium chlorate          4 kg.
-  Copper sulphate          1 kg.
-  Vanadate of ammonia     10 gr.
-  Water                   50 liters
-
-This is solution B, containing the oxidizing agent, and the oxygen
-carriers. Just before using, equal quantities of A and B are mixed, and
-the skins brushed with the mixture. The skins are then dried at 35-45 deg.
-centigrade, at which temperature the color begins to develop. When almost,
-but not entirely dried, the skins are subjected to the action of warm
-vapor, which is allowed to enter the drying chamber, so as to keep the
-temperature about 40 deg. centigrade, the color developing better in this
-way. This operation may be repeated, or the skins are directly treated
-with a solution of 25 kg. of sodium bichromate in 100 liters of water,
-to complete the oxidation. The moist skins are exposed to the air for a
-time, and then dried at 35 deg. C.
-
-This method of dyeing has several advantages over the One-bath Aniline
-Black. It requires fewer brushings, and enables the complete utilization
-of the dye solutions without loss. With three applications of the dye
-mixture by the Oxidation process, as deep and intense a black can be
-obtained as with six brushings by the One-bath method. The dyeings, too,
-are nearly, but not fully as brilliant and even as in the latter case.
-The greater the number of coats of dye that are applied the more regular
-will the dyeing be.
-
-
-3. _Diphenyl Black_
-
-In 1902, the Farbwerke Hoechst, a large German producer of coal tar
-intermediates and dyes, invented an Aniline Black process to which they
-gave the name Diphenyl Black. The chief departure from the previous
-Aniline Black methods was the replacing of part of the aniline oil of the
-dye mixture by Diphenyl Black Base I, which is para-aminodiphenylamine.
-This base has the property of being oxidized to Aniline Black, just like
-aniline oil, and the advantage claimed for the Diphenyl Black is that it
-produces an absolutely ungreenable black. The method of application is
-practically the same as for the other Aniline Black processes, chlorates
-being used as the oxidizing agents, in the presence of oxygen carriers
-such as salts of copper and vanadium. The use of bichromates is dispensed
-with. On account of the comparatively high cost of the Diphenyl Black
-Base I, this method has not found very extensive application, especially
-as highly satisfactory ungreenable blacks can now be produced by other
-methods.
-
-
-4. _Aniline Black by Green's Process_
-
-In 1907, Green, who has done much work in the direction of elucidating the
-character of the Aniline Black process, obtained a patent for a method
-of applying Aniline Black in a manner which was different from all the
-previously known formulas. The invention created great interest, and
-although in its original form it did not find a wide application, many of
-the methods used at the present time are in one way or another derived
-from the idea of Green. A resume of the patent will therefore be given
-here: "The invention relates to the production of an Aniline Black, the
-new process differing from all other known processes by the fact that
-the oxidation of aniline is effected solely or mainly by the oxygen of
-air. The possibility of dispensing with an oxidizing agent depends on the
-discovery that the addition of a small quantity of a para-diamine, or of
-a para-amido-phenol to a mixture containing aniline and a suitable oxygen
-carrier, such as a salt of copper, greatly accelerates the oxidation of
-the aniline by the atmospheric oxygen. Further, whereas in the ordinary
-processes of Aniline Black, the quantity of mineral acid employed cannot
-be materially reduced below the proportion of one equivalent to one
-equivalent of the base, under the new conditions the mineral acid may
-be wholly or partially replaced by an organic acid such as formic acid,
-without the quality of the black being materially affected. As suitable
-oxygen carriers the chlorides of copper have been found to give the best
-results, it being preferrable to use the copper in the form of a cuprous
-salt. This is effected by adding to the dye mixture cupric chloride,
-together with a sulphite or bisulphite in sufficient quantity to reduce
-the cupric salt to the cuprous state, and a sufficient quantity of a
-soluble chloride to keep the cuprous chloride in solution. Among the
-compounds suitable for the production of this black in conjunction with
-aniline are, para-phenylene-diamine, dimethyl-para-phenylene-diamine,
-para-amido-diphenylamine, para-amido-phenol, etc."
-
-This method may be used alone as the other Aniline Blacks, or the dyed
-skins may be after-dyed in a bath containing a logwood dye, or it may be
-used in conjunction with mineral dyes, or with the Oxidation Colors (see
-next chapter). A typical formula for the black by Green's process is the
-following:
-
-  Para-amido-phenol            0.5 kg.
-  Aniline oil                   10 liters
-  Hydrochloric acid 22 deg. Be.     10 liters
-  Acetic acid 40%                5 liters
-  Cold water                    25 liters
-
-This is solution A. Solution B is prepared by dissolving
-
-  Copper sulphate       2 kg.
-  Salammoniac          10 kg.
-  Cold water           50 liters
-
-A and B are mixed, and the mixture applied to the hair of the furs several
-times, drying each time at 35 deg.-40 deg. C. After three coats of dye have
-been applied, a pretty and fairly intense black shade is obtained, which
-is developed further by treating with a solution of 25 grams of sodium
-bichromate per liter of water. The skins are then allowed to dry in air,
-and then if desired, an after-dyeing is made with some other dye.
-
-On account of its extreme fastness, Aniline Black, produced by any of
-the methods outlined above, has attained a justifiable popularity for
-the dyeing of furs, in spite of the necessity of using the more or less
-cumbersome brush method of applying the dye. Very recently there was
-issued to a German company a patent in which is described a method whereby
-furs can be dyed with Aniline Black by the dip process. An abstract of
-the patent (D. R. P. 33402) is as follows: "As is known, aniline salt,
-and similar salts, together with oxidizing agents like bichromates,
-chlorates, etc., cannot be used for dyeing furs by the dip process,
-because the strongly dissociated mineral acid is injurious to the leather.
-The dissociation of the acid can be reduced by adding neutral salts, like
-common salt, or Glauber's salt, so that good results can be obtained by
-dyeing in a bath of the dye mixture, the leather retaining its softness."
-
-Thus far there have been no reports of the successful practical
-application of this patent, so its value cannot be discussed. It is
-extremely doubtful, however, that furs will ever be dyed in the dyebath
-with the present type of Aniline Black formulas, no matter what substances
-are added to prevent the leather from being affected.
-
-
-
-
-CHAPTER XV
-
-FUR DYEING
-
-OXIDATION COLORS
-
-
-The year 1888 may be considered the beginning of a new era in the
-history of fur dyeing; the commencement of a period which was to see
-the time-honored, traditional methods of the masters of the art give way
-to newer methods of an entirely different character; and moreover, the
-initiation of an age when science with its basis of fact and logic, was
-to undertake the rationalization of an industry which had hitherto worked
-upon a more or less irrational, empirical and uncertain comprehension
-of the fundamental principles involved. It was not the work of a single
-day, or even of a year which brought about the virtual revolution in the
-dyeing of furs, but the result of long, patient, systematic effort. About
-this time, the German coal tar industry was attaining its real stride
-along the path of progress and achievement, and had already succeeded in
-reaching, to an appreciable degree at any rate, most users of coloring
-matters, with the consequence that the natural dyes, with their time and
-labor-consuming processes of application were gradually being superseded
-by the new synthetic dyestuffs which could be simply and quickly applied.
-It was now the turn of the fur dyeing industry to receive the attention of
-the scientists and technologists responsible for the growth of the coal
-tar dye industry, and so there appeared in the above-mentioned year, the
-following patents, taken out by a German chemist named Erdmann:
-
-
-D. R. P. 47349
-
-A Process for Dyeing Hair and Feathers
-
-If white hair or feathers are soaked in an aqueous or alcoholic solution
-of para-phenylene-diamine, and then exposed to the slow oxidation of
-the air, or are treated in a second solution with some oxidizing agent,
-then the hair or feathers will be dyed. According to the oxidizing agent
-chosen, and the concentration of the solution used, the color obtained
-will be light or dark, varying from the palest blond to the deepest
-blue-black. Particularly suitable as oxidizing substances are ferric
-chloride, permanganates, chlorates, hypochlorites, bichromates, and
-hydrogen peroxide. The dyeings are fast, that is, they do not come off,
-and the color cannot be removed by washing. Following examples may serve
-to make the process clear:
-
-20 grams pure para-phenylene-diamine and 14 grams caustic soda are
-dissolved in a liter of water. The hair, previously degreased, is soaked
-thoroughly in this solution, and while moist is entered into a three per
-cent solution of peroxide of hydrogen. The action is not instantaneous,
-but after a day, the hair is dyed a dark shade; by repetition of these
-operations a blue-black is obtained.
-
-The para-phenylene-diamine can be replaced in this process by other
-similar bases, such as dimethyl-para-phenylene-diamine, as well as the
-naphthylene-diamines. Since the substances which can be applied by this
-process are uninjurious, the method described can be used to dye human
-hair on the head or beard, and so seems suited to replace for the dyeing
-of hair, the metallic salts and various pyrogallic solutions which are on
-the market, and which are harmful to the health.
-
-
-D. R. P. 51073 Supplement to 47349; Process for Dyeing Hair
-
-This patent was an extension of the original patent to include certain oxy
-and amido-oxy compounds, the method being essentially the same otherwise
-as in the original patent. An illustration of the process is as follows:
-
-73 grams para-amido phenol hydrochloride are dissolved with 40 grams
-caustic soda in a liter of water. The solution dyes hair a golden-yellow,
-which on subsequent treatment with a solution of ferric chloride turns to
-a red-brown.
-
-In these two patents is to be found the basis of the modern fur dyes
-and fur dyeing methods. It is interesting to note that furs were not
-mentioned at all in connection with the process, which was intended
-mainly for dyeing hair, especially on the human head. It was only several
-years later that the value of the method for dyeing furs was realized.
-So about 1894, the Aktien Gesellschaft fuer Anilinfabrikation put upon
-the market three fur dyes under the trade name Ursol, Ursol D, giving
-dark-brown to black shades; Ursol P, giving red-brown colors; and Ursol
-C, giving a yellowish-brown shade. Pyrogallic acid had been previously
-used as a hair dye, and also to a slight extent as a fur dye, so it was
-used in conjunction with the Ursol dyes for shading purposes. The new fur
-dyes were not dyes in the ordinarily accepted sense of the term. They
-were really coal-tar intermediates, substances similar in character to
-aniline, and their dyeing property depended on the fact that they could
-be oxidized either by atmospheric oxygen, or by means of oxidizing agents,
-forming colored insoluble products. When the oxidation of the intermediate
-was caused to take place on the hair the colored product formed on and
-in the hair fibre, and remained fast. The reactions bringing about the
-conversion of the intermediate to the colored insoluble compound are quite
-analogous to those of the Aniline Black process, though possibly not so
-complicated, with the important difference, however, that, while in the
-production of Aniline Black acid is essential, in the present instance the
-oxidation can be carried on in neutral or even alkaline medium. On account
-of the character of the method used in applying the new fur dyes, the
-name Oxidation Colors has been given to them. Strictly speaking, Aniline
-Black is also an Oxidation dye, but it is usually considered in a class
-by itself. The methods used at first in the application of the Ursol dyes
-to furs followed closely the process as described in the patents. The furs
-were first killed, usually by brushing on a lime mixture, drying, and then
-beating out the dust. This operation was repeated, if necessary. Then a
-solution of the desired dye, mixed with an equal volume of 3% peroxide of
-hydrogen was brushed on and the fur allowed to lie exposed to the air. The
-dyeing could also be done by the dip process, less concentrated solutions
-being used. By varying the concentration of the solution, and prolonging
-or shortening the time of action, the shades could be varied from very
-light to very dark, and by combining two or more of the Oxidation Colors,
-many different color effects could be produced. Soon other fur dyes were
-developed and put on the market; for example, Ursol DB, giving blue to
-blue-black shades, and Ursol 2G, yielding yellowish tones suitable for
-mixing with the other colors. Ursol C was discarded shortly after its
-introduction. The dyeings obtained with the Oxidation Colors seemed to be
-very fast, resisting successfully the action of cold or hot water, or even
-hot soap solution. Moreover, a dyed hair examined under the microscope
-appeared to be colored through the epidermis to the medulla, and no
-individual particles of dye could be discerned.
-
-The new fur dyes had many evident advantages over the coloring matters
-in general use at the time. The simplicity of the dyeing operations,
-the short duration of the process, the great tinctorial power of the
-new products, were facts which strongly recommended themselves to the
-progressive fur dyer. The cost of the dyes was higher than that of the
-vegetable dyes, but this consideration was largely overbalanced by the
-saving in time and labor in using them. And yet, the Ursol dyes found
-only a comparatively small market. The majority of fur dyers, always
-conservative and reluctant to turn from the traditional ways of the
-industry were skeptical of, and even hostile towards the new dyes and
-the new methods of dyeing. In a sense, this opposition was justifiable.
-It was not an easy task to relinquish all at once methods which had
-been successfully applied for generations back, and with which they
-were thoroughly experienced, in favor of processes which were radically
-different, and with which they had no experience at all. But some
-enterprising spirits among the fur dyers undertook to try out the new
-products and it was not long before the skeptics had good cause for
-condemning the work and achievements of the chemists as far as fur dyeing
-was concerned. The new type of dyes did possess some of the advantages
-claimed for them, but they also possessed many highly objectionable
-features, which had never been manifest with the vegetable dyes. First
-of all, the dyeings were not so fast as had at first appeared, for the
-color came off the hair when the furs were rubbed, brushed or beaten.
-Then it was observed that after a short time some of the dyeings changed
-color, and at the same time the hair lost its gloss and became brittle.
-The condition of the leather after dyeing was anything but satisfactory.
-Most serious of all, however, was the appearance among the workers in
-the dyeing establishments, and also among the furriers who worked with
-the dyed skins, of certain pathological conditions which had hitherto
-been unknown. Various skin diseases, eczemas, inflammation of the
-eyes, asthmatic affections and intestinal irritations were some of the
-afflictions which were directly attributable to the use of fur dyes of
-the Ursol type. Medical science was at a loss to know how to treat these
-ailments, because their nature was not understood.
-
-Here indeed, were obstacles threatening to destroy all the hopes which
-the discovery of the new class of dyes had aroused, and to check at the
-outset the possibility of rational progress in the fur dyeing industry.
-But the men of science were not content to let the matter drop thus.
-Difficult problems had been solved before, and surely there must be
-some way of overcoming the objections and deleterious features of a
-system of fur dyeing which had so much potential merit. Where hindrances
-sprang up in the path of progress, it was the duty of the chemist to
-remove them, and when difficulties arose, it was up to him to resolve
-them, as far as was humanly possible. So the chemists who had been
-responsible for the introduction of the Oxidation Colors set themselves
-to the task of eliminating the undesirable or injurious qualities. It
-was many years before the results of painstaking effort and persistent
-study cleared up the causes of all the objectionable aspects of the fur
-dyes, and suggested means of overcoming them satisfactorily. The work
-had been directed to the improvement of the dyes and of the methods of
-dyeing with them. Purer intermediates were produced, and more easily
-soluble ones, so that there would be no possibility of ultra-microscopic
-particles of the dye being deposited on the surface of the hair from the
-dye solution, instead of being taken up within the hair fibre. It was
-this superficial deposition of minute crystals of the dye or of the only
-partially oxidized intermediate, on the hair, crystals so fine as to be
-invisible in the ordinary high-power microscope, which caused the color
-to come off when the furs were brushed or beaten, giving rise to a dust
-which was frequently very injurious to the health. Then, mordants were
-adopted to help fix the dyes, compounds of copper, iron, and chromium
-being used as formerly with the vegetable dyes, and the range of shades
-was also increased thereby. Certain of the Oxidation Colors had a tendency
-to sublime off the hair, so the dyed hair was chemically after-treated
-in such cases to prevent this. The causes of the pathological aspects of
-dyeing with the Oxidation fur dyes were not so readily disposed of. But
-the adoption of devices to prevent the formation and circulation of dust
-during the handling of the dye, the employment of adequate protection
-against contact with the dye or its solutions, the use of the most dilute
-solutions possible in dyeing, the thorough washing of the dyed skins to
-remove any excess of the coloring matter, the prevention of dust formation
-in the drying of the skins, and the rigid observance of, and adherence to
-hygienic laws, were all factors in the elimination of the health-impairing
-phases of dyeing with the Oxidation Colors.
-
-It was only after all these improvements had been accomplished that the
-fur dye intermediates began to acquire a degree of popularity among fur
-dyers, and strange as it may seem, there was a more ready market for
-these dyes in America, than in Germany where they were manufactured. Other
-manufacturers of coal-tar intermediates also began to produce fur dyes,
-and so, in addition to the Ursols, there were the Nako brand, the Furrol
-brand, the Furrein brand, and one or two others. New dyes were invented,
-until the whole range of colors suitable for fur dyeing had been produced.
-The black dye, however, presented some difficulty. A black dye which would
-rival logwood blacks could not be attained. Ursol DB in conjunction with
-Ursol D was being used to produce bluish-blacks, but the dyeings were not
-fast, turning reddish after a time. In 1909, a patent was taken out for
-a dye mixture, which was made up like the DB brand, but instead of using
-toluylene diamine with para-phenylene-diamine, the new dye was made up of
-a methoxy, or ethoxy-diamine with para-phenylene-diamine, and it yielded
-brilliant bluish-blacks, which were fast, and which very nearly approached
-the logwood black in luster, intensity, and bloom. For some purposes,
-however, the production of a black color is still dependent on the use of
-the logwood dye.
-
-When the Great War cut off to a large degree the importation of skins
-dyed in Europe, the American fur dyeing industry developed tremendously,
-and in a comparatively short time was able satisfactorily to accomplish
-in the way of dyeing furs, what had taken foreign dyers a much longer
-period to attain. It had been previously considered that furs could be
-dyed properly only by European fur dyers, but the achievements in this
-direction by Americans fully dispelled this belief. But the success of
-the fur dyers in America might not have been so marked or rapid, had it
-not been for the work of the American chemists. The war had also shut off
-the supply of German dyes, upon which the dyeing industries of America
-had formerly been dependent, so enterprising chemists in this country
-undertook to fill the need, and in a surprisingly short time, American fur
-dyes, in every respect the equal of the foreign product were offered to
-the American fur dyers, and at the present time, the requirements of the
-fur dyeing industry in this country are being adequately met by domestic
-producers. Among the brands on the market are the Rodol, Furamine,
-Furol, and several others. The Oxidation Colors are now being offered
-in a high state of purity, and easily soluble, free from any poisonous
-constituents, and there is absolutely no reason for the appearance of
-any pathological conditions among workers on dyed furs, or users of such
-furs, provided the necessary precautions have been taken in the dyeing
-process. The occurrence of any affection which can be traced to dyed fur,
-cannot possibly be due to the dye itself, but to gross carelessness and
-negligence in dyeing, and in any such event, the dyer responsible should
-be brought to account.
-
-In order to get a better understanding of the nature and action of the
-Oxidation Colors, a typical one will be studied in some detail. The most
-important one in this class is para-phenylene-diamine, usually designated
-by the letter D in all commercial brands of this fur dye, while its
-chemical formula is represented as C{6}H{4}(NH{2}){2}. When pure it occurs
-in colorless, crystalline lumps, which rapidly turn brown when exposed
-to the air; the technical product of commerce is of a dark-brown color.
-It dissolves readily in hot water when pure, and also in acids. At one
-time the hydrochloride was used instead of the free base, on account
-of its greater solubility, but now a base is made which is sufficiently
-pure to be very soluble in water. There are several methods of preparing
-para-phenylene-diamine: first, by the reduction of amido-azobenzol,
-the product obtained in this way always containing a slight amount of
-aniline, which reduces the solubility, and also gives rise to poisonous
-oxidation products during the dyeing process; second, by the reduction
-of paranitraniline, the quality and solubility of the product in this
-case depending on the purity of the starting material; and third, by the
-treatment of para-dichloro-benzol with ammonia under pressure, the best
-product being obtained by this method. The crude para-phenylene-diamine,
-made by any of the above processes, is generally distilled in vacuo, the
-refined base being obtained as lumps with a crystalline fracture.
-
-The first step in the oxidation of the para-phenylene-diamine is the
-formation of quinone di-imine, NH:C{6}H{4}:NH. This is a very unstable
-compound in the free state, and even in aqueous solution it decomposes
-within a comparatively short time, or combines with itself to form a more
-stable substance. Quinone di-imine has a very sharp, penetrating odor, and
-produces violent local irritations wherever it comes in contact with the
-mucous membrane. If a small quantity of para-phenylene-diamine is absorbed
-into the human body, by breathing the dust, or otherwise, the formation
-of quinone di-imine takes place internally with consequent irritation of
-the mucous lining throughout the body. The various pathological conditions
-mentioned before may be ascribed to irritation caused by quinone
-di-imine. In any dyeing process where there is a possibility of the
-formation of quinone di-imine, as is the case with most dyes containing
-para-phenylene-diamine, special precautions must be taken by the workers
-in handling the dye or coming in contact with its solutions, and no one
-who is particularly sensitive to irritation should be permitted to work
-in a place where such dyes are used.
-
-The next step in the oxidation of the para-phenylene-diamine is the
-formation of what is called Bandrowski's base. Three parts of the quinone
-di-imine combine with themselves, forming a substance of a brown-black
-color, which was formerly regarded as the final oxidation product. The
-formula of Bandrowski's base is represented by the following chemical
-hieroglyphics:
-
-  (NH{2}){2}.C{6}H{3}.N:C{6}H{4}:N.C{6}H{3}(NH{2}){2}.
-
-Further investigation has shown that the oxidation proceeds beyond this
-stage with the formation of a compound of what is known as the azine type,
-which is depicted by the chemist as
-
-                   NH          NH
-  (NH{2}).C{6}H{3}<  >C{6}H{2}<  >C{6}H{3}.NH{2}.
-                   NH          NH
-
-It is by no means certain that this substance is the true coloring matter
-obtained by the oxidation of para-phenylene-diamine, for the reactions
-may continue still farther, producing even more complicated oxidation
-products. Scientific research and study has not as yet gone beyond this
-stage.
-
-The reactions of the other dyes of the Oxidation type are quite similar to
-those of para-phenylene-diamine, some being simpler, and others being even
-more complex. The presence of certain chemical groups in the intermediate,
-or the relative position of such groups are factors responsible for the
-variations in shade.
-
-With the various mordants, the Oxidation Colors give different shades, and
-a great range of colors can be produced either by combining mordants, or
-combining dyes, or both. The following tables illustrate the shades formed
-with the customary mordants.
-
-  =========================================================================
-           |    CHROME     |     COPPER     |     IRON     |    DIRECT
-  ---------+---------------+----------------+--------------+---------------
-  Ursol D  | brown black   | coal black     | coal black   | dark brown to
-           |               |                |              |   brown black
-  Ursol P  | dull red brown| dull dark brown| grey brown   | light brown
-  Ursol 2G | yellow brown  | dull yellow    | yellow brown | dull yellow
-           |               |   brown        |              |
-  Ursol A  |    ...        |     ...        | blue black   | blue to blue-
-           |               |                |              |   black
-  Ursol 4G | light brown   | medium brown   | yellow       | pure yellow
-  Ursol 4R | orange brown  | light yellow   | red brown    | orange red
-           |               |   brown        |              |
-  Ursol    |               |                |              |
-    Grey B | greenish grey | greenish grey  | mouse grey   |     ...
-  Ursol    |               |                |              |
-    Grey R | brownish grey | brownish grey  | reddish grey |     ...
-  ---------+---------------+----------------+--------------+---------------
-
-Fur dyes of American make being equal in every way to the German product,
-show the same color reactions with the various mordants. The following
-table shows the shades produced with the same mordants as above:
-
-  =========================================================================
-           |    CHROME     |    COPPER     |     IRON      |     DIRECT
-  ---------+---------------+---------------+---------------+---------------
-  Rodol D  | brown black   | coal black    | coal black    | brownish black
-  Rodol P  | red brown     | dark brown    | grey brown    | light brown
-  Rodol 2G | yellow brown  | yellow brown  | yellow brown  | dull yellow
-  Rodol 4G | light brown   | light brown   | reddish brown | pure yellow
-  Rodol A  |     ...       | blue black    |     ...       | blue black
-  Rodol    |               |               |               |
-    Grey B | greenish grey | greenish grey | mouse grey    |     ...
-  Rodol    |               |               |               |
-    Grey R | greenish grey | brownish grey | mouse grey    |     ...
-  ---------+---------------+---------------+---------------+---------------
-
-All these shades are produced by dyeing in a bath containing a _neutral_
-solution of the dye. Sometimes the dye comes in the form of a salt of
-a mineral acid, like hydrochloric or sulphuric acid, in which case a
-sufficient amount of an alkali, usually ammonia, is added to liberate
-the free base. According to the Cassella Co., German manufacturers of the
-Furrol brand of fur dyes, the dyeing can also be carried on in slightly
-alkaline or in slightly acid solution, a different series of shades being
-obtained in each instance. Ammonia is used to render the bath alkaline,
-and formic acid to make it acid. The most customary practise, however, is
-to use neutral solutions of the dyes.
-
-For preparing the mordant solutions much smaller quantities of the
-metallic compounds are used than in the case of the vegetable dyes. With
-chrome mordants cream of tartar is always employed as an assistant, and
-occasionally also with copper and with iron mordants. With copper, and
-also with iron mordants no addition is made at all, or sometimes a small
-quantity of acetic acid is added. The temperature of the mordant solution
-is kept about 30 deg. C., and the duration of the mordanting varies from 2-24
-hours according to the depth of shade desired. The concentration of the
-solution may also be varied, it sometimes being just as well to use a
-strong mordant solution and less duration of mordanting. Chrome may be
-combined with copper, and iron may be combined with copper, but chrome
-and iron do not go together as mordants. Some typical average mordanting
-formulas are as follows:
-
-         Chrome mordant.
-  Bichromate of soda    2.5 gms.
-  Cream of tartar       1.5 gms.
-  Water                   1 liter
-
-         Copper mordant.
-  Copper sulphate         2 gms.
-  (Acetic acid 50%        2 gms.)
-  Water                   1 liter
-
-          Iron mordant.
-  Ferrous sulphate        2 gms.
-  (Acetic acid 50%        2 gms.)
-  Water                   1 liter
-
-or,
-
-  Iron pyrolignite 30%   10 gms.
-  Water                   1 liter
-
-      Chrome-copper mordant.
-  Bichromate of soda      2 gms.
-  Copper sulphate      0.25 gms.
-  Cream of tartar       1.0 gms.
-  Water                   1 liter
-
-       Copper-iron mordant.
-  Copper sulphate         2 gms.
-  Ferrous sulphate        2 gms.
-  (Acetic acid 50%        2 gms.)
-  Water                   1 liter
-
-The killed skins are immersed in the mordanting solution, and allowed
-to remain the required length of time. They are then thoroughly rinsed
-to remove any excess of the mordant, and are hydro-extracted. Under no
-circumstances should mordanted skins be permitted to dry, for they would
-be unfit for use again.
-
-The dyebath is next prepared by dissolving the necessary quantity of the
-dye, varying from 0.1 gm. to 10 gms. per liter. Then if the solution must
-be neutralized, the ammonia is added and the temperature of the bath is
-brought to 30-35 deg. C. by the addition of cold water. This temperature is
-maintained throughout the dyeing operation. To the solution is added the
-oxidizing agent. Ordinary commercial peroxide of hydrogen containing 3%
-by weight is the usual oxidizer, although perborates have been suggested.
-15-20 parts of peroxide of hydrogen for every part of dye are added, and
-the dye solution brought to the proper dilution. As soon as the dyebath is
-ready, the skins are entered, and worked for a short time to effect even
-penetration. They are then left in the dyebath for 2-12 hours or longer
-according to the depth of shade. After being satisfactorily dyed, the furs
-are rinsed thoroughly, hydro-extracted and dried and finished. Where the
-dye is to be applied by the brush to the tips of the hair, stronger dye
-solutions are used, the brushed skins being placed hair together and let
-lie for about 6 hours in order to permit the color to develop, after which
-the furs are dried and drum-cleaned.
-
-Some shades, particularly black, have a tendency to rub off slightly. In
-order to overcome this, the dyed furs, after rinsing, are treated with a
-cold solution of 1/2 part of copper sulphate per 1000 parts of water, for
-3-4 hours, then without rinsing, hydro-extracted and dried. Furs which
-have been tipped are brushed with a 1-2% solution of copper sulphate and
-dried. Care must be taken in this after-treatment, for the use of too
-strong a solution of copper sulphate, or too prolonged action of such a
-solution will materially alter the shade of the dyed fur.
-
-A few typical formulas will serve to illustrate the general methods of
-employing the Oxidation Colors:
-
-
-_Brown Sable Imitation on Unsheared Rabbit_
-
-The skins are killed with soda, soured, and washed, then mordanted with
-
-  Bichromate of soda      2 grams
-  Copper sulphate       .25 grams
-  Cream of tartar         1 gram
-  Water                   1 liter
-
-for 24 hours. Then washed, and dyed for 24 hours with
-
-  Fur Brown 2G[3]         3 grams
-  Hydrogen peroxide      45 grams
-  Water                   1 liter
-
-Wash and dry the skins, then brush the tips with
-
-  Fur Brown D[3]         20 grams
-  Hydrogen peroxide     400 grams
-  Water                   1 liter
-
-  [3] Inasmuch as most manufacturers use the same letters to designate
-      the various dyes, any equivalent brand of fur dye may be used in
-      place of those here mentioned.
-
-
-_Black on Sheared Muskrat_
-
-The skins are killed with soda, soured, and washed, then chrome mordanted
-for 6 hours. Then they are dyed for 6 hours with
-
-  Rodol P               1.5 grams
-  Pyrogallic acid        .7 grams
-  Ammonia               2.0 grams
-  Hydrogen peroxide      45 grams
-  Water                   1 liter
-
-The dyed skins are washed and dried, then tipped with
-
-  Rodol D                20 grams
-  Rodol DB                2 grams
-  Hydrogen peroxide     450 grams
-  Water                   1 liter
-
-
-_Brown on Thibet Sheep Skin_
-
-The killed skins are mordanted for 6 hours with a chrome mordant, then
-dyed for 6 hours with
-
-  Ursol P                 1 gram
-  Pyrogallic acid         1 gram
-  Ammonia                 2 grams
-  Hydrogen peroxide      40 grams
-  Water                   1 liter
-
-It is also possible to combine dyeings with the Oxidation Colors with
-Vegetable dyeings, or with Aniline Black. For example, if it be desired
-to produce an imitation skunk on a raccoon, and an exceptionally fast and
-intense and lustrous black on the tips of the hair, the skins are dyed
-in the bath with the Oxidation dyes, and the tips of the hair are brushed
-with a mixture such as described under Vegetable Colors for the production
-of French seal, as follows:
-
-
-_Imitation Skunk on Raccoon_
-
-The skins are killed with caustic soda, soured and washed, then mordanted
-with an iron-copper mordant as described, and then dyed with
-
-  Fur Grey R              3 grams
-  Ammonia                 2 grams
-  Peroxide of hydrogen   45 grams
-  Water                   1 liter
-
-After washing and drying, the dyed skins are brushed over with a mixture
-such as used for dyeing French seal with Vegetable Colors.
-
-In a similar manner, the Oxidation Colors may be used to give a base color
-to furs dyed by the Aniline Black process.
-
-It is apparent from these few illustrations that a great variety of shades
-can be produced, and the dyeing of imitations of the better class of furs
-on cheaper skins is a comparatively simple matter, after an understanding
-of the nature of the dyes has been obtained, and a certain amount of skill
-acquired in working with these dyes.
-
-
-
-
-CHAPTER XVI
-
-FUR DYEING
-
-COAL TAR DYES
-
-
-In addition to the Aniline Blacks and the Oxidation Colors already
-discussed there are certain of the synthetic coal tar dyes such as are
-generally used in the dyeing of textiles, which can also be applied on
-furs. There are several classes of these dyes, varying somewhat in their
-nature, and consequently in their manner of application; in the main they
-produce bright shades, such as are but seldom used on furs, yet which may
-occasionally serve for the production of novel effects. Basic, acid and
-chrome colors are the types which can be employed.
-
-Basic colors possess great fullness and tinctorial strength, but have a
-tendency to rub off, and the tips of the hair take a darker shade with
-these dyes than the rest of the hair. The addition of acetic acid and
-Glauber's salt to the dyebath will result in a more uniform dyeing. On
-account of the comparatively poor fastness to rubbing and washing, basic
-dyes are used only for dyeing furs which are intended for cheap carpet
-rugs, such as sheep and goat. They may also find use in the production
-of light fancy shades on other white furs. The procedure is usually as
-follows: The furs are killed in the customary manner with soap and soda
-or ammonia, or if this is insufficient, with milk of lime. A soap-bath is
-then prepared containing 2.5-6 grams of olive-oil soap per liter of water.
-The temperature of the bath is brought to 40 deg. C. To this is added the
-solution of the dyestuffs, prepared by mixing the required color or colors
-with a little acetic acid to a paste, and then pouring boiling water on
-the mixture until dissolved. Undissolved particles or foreign matter are
-removed by passing this solution through a cotton cloth or sieve, and
-the clear solution then mixed with the soap-bath. The well-washed skins
-are then entered into the dyebath and immersed for about half an hour,
-or until the desired depth of shade is obtained. They are then removed,
-pressed or hydro-extracted and dried. For the production of light shades,
-the following dyes may be used:
-
-For cream, light sulphur-yellow, maize, salmon, etc.
-  Combinations of
-  Thioflavine
-  Rhodamine B
-  Irisamine G
-
-For greenish-yellows
-  Combinations of
-  Thioflavine
-  Victoria Blue B
-
-For light pink
-  Rhodamine B
-  Irisamine
-  Rose Bengal Extra N
-
-For purple
-  Methyl Violet 3B-6B
-  Crystal Violet
-
-For sky-blue
-  Victoria Blue B
-
-For white
-  Victoria Blue B (Milk-white)
-  Methyl Violet 3B-6B
-  Crystal Violet (Ivory-white)
-
-To produce very delicate shades, the moist dyed skins are subjected to a
-sulphur bleach overnight, to lighten the color, then rinsed, and dried.
-Full, brilliant shades may be obtained by dyeing in a bath of 40 deg. C.,
-acidulated with 2-3 grams of acetic acid per liter of solution, the
-following dyestuffs being suitable:
-
-For yellow to orange
-  Thioflavine
-  Paraphosphine
-  Rhodamine
-  Safranine
-  New Magenta O
-
-For pink
-  Rhodamine B
-  Rose Bengal Extra N
-
-For light red
-  Safranines
-
-For bordeaux and red
-  Magenta
-  New Magenta
-  Russian Red
-  Cerise
-
-For violet
-  Methyl Violet 6B-4R
-  Crystal Violet 5B
-
-For blue
-  Victoria Blue B
-  Methylene Blue BB
-  New Methylene Blue N
-
-For green
-  Malachite Green Crystals
-  Brilliant Green Crystals, or combinations of
-  Thioflavine
-  Diamond Phosphine
-  Victoria Blue B
-
-For brown
-  Chrysoidines
-  Bismarck Browns
-
-In dyeing skins with harder hair than that of sheep or goat, mere killing
-is insufficient to render the hair capable of taking up the dye. The
-skins are therefore immersed before dyeing, in a cold, weak solution
-of chloride of lime, the affinity of the hair for the dye being thereby
-greatly increased.
-
-Acid dyes are employed when a greater fastness is required than can be
-obtained with the basic colors. Sulphuric acid in a quantity equal to
-half the weight of the dyestuffs used, together with four times that
-quantity of Glauber's salt is added to the dyebath. Formic acid may be
-used in place of the sulphuric acid, very good results being obtained.
-The skins are immersed in the dyebath, and worked until thoroughly soaked
-with the dye liquor, and then allowed to remain until the proper depth
-of shade is attained, or overnight. The temperature of the solution is
-about 40 deg. C., and only very light shades can be produced in this manner.
-In 1900 and again in 1914, the Cassella Co., a large German manufacturer
-of dyestuffs, obtained patents for processes enabling the dyeing of
-furs in hot solution with the acid dyes. The method required that the
-skins be chrome-tanned in order to render them resistant to the action
-of hot solutions, the addition of a small amount of formaldehyde to the
-chrome solution increasing this effect. The skins are then treated with a
-solution of chloride of lime in order to increase the affinity of the hair
-for the dyestuffs. The method as it is now practised is as follows: The
-skins which have been cleaned and washed are chrome tanned by the method
-as described in the chapter on Tanning Methods, 60 grams of formaldehyde
-being added to every 10 liters of the chrome solution. After proper
-tanning the skins are rinsed, and while still moist they are subjected to
-a treatment with chloride of lime. They are first immersed for 15 minutes
-in a cold bath containing 120 grams of hydrochloric acid 32-36 deg. Twaddell
-per 10 liters of water, then without rinsing, they are entered into a bath
-made up by adding gradually in four portions the clear solution of 2-4
-grams of the chloride of lime per 10 liters of water. After working for
-an hour, the skins are removed and entered again into the acid solution,
-in which they are worked for another 15 minutes. In order to neutralize
-and remove the last traces of the chloride of lime from the furs, they are
-rinsed in a luke-warm bath containing 1-2 grams of sodium thiosulphate,
-or hyposulphite of soda, in 10 liters of water. The skins are then rinsed
-again, and hydro-extracted, or pressed, and are ready for dyeing. The
-dyebath is prepared with the required quantity of dye, to which is added
-10-20% Glauber's salt and 2-5% acetic acid (both calculated on the weight
-of the skins). The skins are entered at 20 deg. C., then after three-quarters
-of an hour to 40 deg. C., and then after another hour slowly to 50-55 deg. C. For
-blacks, the temperature is raised as high as 65 deg. C. After dyeing the skins
-are treated with a solution containing per 10 liters
-
-  90-120 grams of olive-oil soap
-   12-25 grams olive oil
-      12 grams ammonia
-
-for 15 minutes, then hydro-extracted and dried, without further rinsing.
-
-For this method of dyeing, the following dyes may be used:
-
-For yellow and orange
-  Fast Yellow S
-  Acid Yellows
-  Naphthol Yellow S
-  Tropaeoline
-  Orange GG, R, II, IV
-
-For reds
-  Acid Reds
-  Lanafuchsine
-  Azo Orseille
-
-For violet
-  Azo Wool Violet
-  Acid Violets
-
-For blue
-  Cyanole FF
-  Azo Wool Blue
-  Naphthol Blue R
-  Formyl Blue B
-
-For green
-  Naphthol Green B
-  Fast Acid Green
-  Cyanole Green
-
-For brown, combinations of
-  Fast Yellow S
-  Acid Yellows
-  Tropaeoline DD
-  Orange GG
-  Lanafuchsine
-  Indigo Blue N
-  Cyanole B
-  Fast Acid Green BN
-
-For black
-  Naphthylamine Blacks
-  Naphthol Blacks
-  Naphthol Blue-black
-
-For grey
-  Silver Grey N
-  Dyed with the addition of 1/2-1% of alum
-
-The chrome colors are dyed on furs when very fast shades are desired, all
-the fancy colors being produced in this manner, but for black, only the
-acid dyes are suitable. The preparation of the skin is exactly the same as
-for the acid colors, except that the treatment with chloride of lime may
-be omitted, although for very full shades it is desirable. The dyeing is
-carried out as follows: The dyebath is prepared with the requisite amount
-of the desired dyestuff, which is previously dissolved, and to this is
-added a solution of sodium bichromate, the amount of this substance being
-half the weight of the dye. The solution is heated and the skins entered
-and dyed for 1-2 hours at 70-80 deg. C. Then the dyebath is exhausted by the
-addition of 1/3% acetic acid, the skins being worked for another half
-hour, then rinsed, hydro-extracted and dried. Any of the one-bath chrome,
-or after-chrome colors may be used for this method.
-
-Recently methods have been patented for the dyeing of furs by means of
-the vat colors. Vat dyes are among the fastest coloring matters ever
-produced, and their application on furs would be a great advantage, if
-suitable shades could be obtained. The general process for dyeing with vat
-colors, consists in reducing the dye, which is usually very insoluble,
-into a soluble "leuco" compound, by means of hydrosulphites in the
-presence of alkalies. The leuco compound is not a dye itself, but when
-the fibre absorbs it, and is then exposed to the air, the leuco compound
-is reoxidized to its original insoluble form, which remains fast and
-permanent. The use of strong alkalies in vat dyeing has hitherto been a
-great obstacle in the use of these dyestuffs, but in 1917, the Farbwerke
-Hoechst, a large German dye works, patented a process as follows: "A
-process for dyeing furs with vat colors. The dyeing is done in solutions
-of the vat dyes (after the addition of gelatine or some other protective
-colloid), which are rendered neutral or only slightly alkaline with
-ammonia, by neutralizing the caustic soda of the solution of the leuco
-compound of the vat dyes by the addition of ammonium salts, or suitable
-acids. The dyeings thus obtained are uniform and fast, the leather is dyed
-to only a slight degree, and shows no deleterious effects of the dyebath
-on the tannage." As a practical application of this process, another
-patent was taken out by the same company, also in 1917, as follows:
-"A process for producing fast blacks on furs, consisting of dyeing a
-ground color with appropriate vat dyes in a hydrosulphite vat, and after
-oxidation in air, topping with an Aniline or Diphenyl black. The dyeings
-obtained by the combination of vat dyes which are fast to oxidizing
-agents, with an oxidation black, have an appearance matching that of
-logwood black in beauty; and with a dark-blue to blue-black under-color,
-and a full, deep black top color, cannot be distinguished from logwood.
-These dyeings also have the advantage of being faster to light than
-logwood or other blacks."
-
-While these processes undoubtedly have many meritorious qualities which
-make them interesting, they do not seem as yet, to have attained any
-great practical application. However, it is a field of fur dyeing which is
-worth while developing, and with certain necessary improvements in these
-processes, the vat dyes may yet supersede partially some of the other
-methods of dyeing furs.
-
-
-
-
-CHAPTER XVII
-
-BLEACHING OF FURS
-
-
-Bleaching is for the purpose of lightening the color of furs, and is
-most generally applied to white-haired skins such as white fox, ermine,
-and occasionally white lambs of all kinds, and white bears. Among such
-furs, pelts of a naturally pure white tone are relatively scarce, while
-in the majority of cases the color ranges from a pale creamy white to a
-decidedly yellowish shade. Colors which vary from the pure white detract
-considerably from the attractiveness and consequent value of the fur, and
-indeed, some pelts are so far off shade that they can only be used when
-dyed a darker color. Most white skins which are but slightly inferior in
-color can be brought to a pure white by bleaching, and they can then be
-used natural. Some pelts, on the other hand, are particularly resistant
-to the action of bleaching agents and cannot be sufficiently decolorized
-to render them suitable for use natural, so these are also dyed. For the
-production of certain delicate or fancy dyed shades on white furs, it is
-often necessary to bleach the skins in order to be able to obtain pure
-tones. Such instances are not very common, however. Occasionally dark
-furs, such as beaver, are bleached on the tips of the hair, a golden shade
-being obtained thereby, which at one time was quite popular, but recently
-such effects have not been in vogue.
-
-In the bleaching of furs, two steps may be distinguished, first
-degreasing, and second, bleaching proper. In the preliminary operations
-of fur dressing, the furs are treated with soap or weak alkalies to
-cleanse them and to remove excess oil from the hair. During the various
-processes and manipulations, the hair, especially on white skins, may
-become soiled or somewhat greasy again, so it is advisable to repeat
-the cleaning process. This should in every case be as light as possible,
-using a weak solution of soap for the softer and cleaner pelts, or dilute
-solutions of ammonium carbonate or soda ash for the more greasy-haired
-skins. The skins are then thoroughly rinsed to remove all traces of
-the degreasing material. This step is very essential in order to obtain
-uniform bleaching.
-
-Broadly speaking, there are two general methods which can be used in
-bleaching furs, one involving the use of what are known as reducing
-agents, and the other employing oxidizing substances.
-
-Among reducing agents which can be used for bleaching furs are sulphurous
-acid, and its salts such as sodium bisulphite and sodium sulphite;
-hydrosulphites, and derivatives.
-
-1. ~Sulphurous acid.~--When sulphur is burned, sulphur dioxide gas
-is formed. In the presence of moisture, or when dissolved in water,
-this gas forms sulphurous acid, which is one of the most commonly used
-bleaching chemicals for all sorts of materials, and is very effective
-for decolorizing furs. The procedure usually followed is to hang up the
-moistened skins on wooden rods in a more or less cubical chamber made of
-stone or brick, and lined with wood or lead. No other metals may be used,
-because they are quickly corroded by the sulphurous acid. The requisite
-quantity of sulphur is placed in a pot in the bleaching chamber, and then
-ignited, after which the doors are shut tight. The fumes of the burning
-sulphur in contact with the moist hair readily exert their bleaching
-action on the furs, and the operation is allowed to proceed for six or
-eight hours, or overnight. Then by means of fans or other devices, the
-air filled with sulphur dioxide gas is withdrawn from the chamber, and
-replaced by fresh air. The door is opened, the skins removed, exposed to
-the air for a time, then rinsed, and finally dried and finished. Sometimes
-one operation is not enough to sufficiently bleach the hair, so the
-process is repeated. Sulphur dioxide gas can now be obtained compressed
-in cylinders, which are more convenient to handle than burning sulphur.
-The flow of gas which is introduced into the bleaching chamber by means
-of a nozzle attached to the cylinder, can be regulated, and the bleaching
-thus retarded or accelerated.
-
-2. ~Sodium bisulphite and sodium sulphite.~--These salts of sulphurous
-acid are effective in their bleaching action only when in solution in the
-presence of acids. The acids liberate sulphurous acid from the salts,
-so this method is virtually the same as 1. Instead of using the salts
-of sulphurous acid, sulphur dioxide may be dissolved in water, and the
-solution used for bleaching by immersing the furs in it. This procedure,
-while consuming somewhat less time than the chamber process, is more
-likely to affect the leather, which would have to be retanned. The
-principle is the same as that involved in method 1.
-
-3. ~Hydrosulphites and derivatives.~--The bleaching agent can be prepared
-by adding zinc dust to commercial bisulphite of soda dissolved in about
-four times its weight of water until no more reaction is evident. Milk
-of lime is then added to precipitate the zinc, and the clear supernatant
-liquid of 1.5 deg.-5 deg. Tw. is used for bleaching. The skins are immersed
-for 12-24 hours, taken out, washed and finished. Instead of preparing
-the hydrosulphite, the commercial products may be used with greater
-convenience, a solution containing 1-4% of the hydrosulphite powder being
-used, and the skins treated in this until satisfactorily bleached.
-
-The bleaching action of sulphurous acid and hydrosulphite is supposed to
-be due to the reduction of the coloring matter of the hair to a colorless
-compound; or possibly to the formation of a colorless compound of the
-bleaching material with the pigment. The former seems the more probable
-explanation, because the change is not a permanent one, the original
-natural color returning after a long exposure of the bleached fur to air
-and light. However, the results are sufficiently enduring to satisfy the
-requirements of the trade in the class of furs on which these methods of
-bleaching are used.
-
-Bleaching chemicals with an oxidizing action generally used for
-decolorizing furs are hydrogen peroxide and peroxides; occasionally
-hypochlorites and permanganates are also used.
-
-1. ~Hydrogen peroxide.~--Hydrogen peroxide is usually employed for
-bleaching in the form of its 3% solution, to which is added about 20
-cubic centimeters of ammonia per liter. The ammonia serves partially to
-neutralize the acid which commercial peroxide generally contains, and
-also to facilitate the bleaching action. The thoroughly degreased skins
-are immersed in the solution until the hair is completely wetted by it,
-are then removed, and evenly pressed or hydro-extracted, after which
-the pelts are hung up to dry in the air. As the hair becomes drier,
-the concentration of the peroxide becomes greater, and consequently the
-bleaching action is stronger. Where there is a likelihood of the leather
-being affected by the bleaching solution, the ammoniacal peroxide may
-be applied to the hair with a fine sponge or brush until sufficiently
-wetted, and then hanging the skins up to dry. Repetition of the process
-is sometimes necessary to obtain pure white, but the results are always
-excellent.
-
-2. ~Peroxides.~--The most important of these is sodium peroxide, which
-comes on the market as a yellowish-white powder, which must be kept dry,
-and away from any inflammable material, as fires have been caused by the
-contact of the peroxide with such substances. When dissolved in water, it
-is equivalent to a strongly alkaline solution of peroxide of hydrogen.
-
-  Na{2}O{2} + 2H{2}O = H{2}O{2} + 2NaOH
-   sodium      water   peroxide   caustic
-  peroxide                of       soda
-                       hydrogen
-
-When dissolved in acid, the alkali is neutralized, and a neutral solution
-of peroxide of hydrogen and a salt is obtained, and this method is used
-to obtain peroxide of hydrogen cheaply.
-
-  Na{2}O{2} + H{2}SO{4} = H{2}O{2} + Na{2}SO{4}
-              sulfuric                 sodium
-                acid                  sulphate
-
-3 parts of sodium peroxide are slowly dissolved in a cold 1% solution of
-4 parts of sulphuric acid, stirring during the addition, and making the
-resulting solution neutral to litmus paper, acid or more sodium peroxide
-being added as needed. There is then added 3-6 parts of a solution
-of silicate of soda of 90 deg. Tw. The skins are immersed until properly
-bleached, taken out, passed through a weak acid solution, then washed
-and finished. This method generally requires the leather to be retanned
-after bleaching. Another process, which involves the use of peroxides,
-but which is not commonly practised, consists in rubbing the hair with
-a pasty mixture of equal parts of water, barium dioxide, and silicate of
-soda, hanging up the skins to dry, and then beating and brushing the hair.
-
-3. ~Permanganates.~--The only member of this group that finds practical
-application for bleaching purposes is potassium permanganate. The skins
-are immersed in a 0.1% solution of the crystals of potassium permanganate,
-until the hair acquires a deep brown color. They are then removed, rinsed,
-and entered into a second bath containing sulphurous acid in solution,
-prepared by acidifying a solution of sodium bisulphite. The skins are then
-worked in this until fully bleached. It is the permanganate which does
-the bleaching, the sulphurous acid being for the purpose of dissolving
-the brown compound of manganese formed on the hair.
-
-4. ~Hypochlorites.~--Chloride of lime and sodium hypochlorite, which is
-prepared from the former, are the chief chemicals of this type used for
-bleaching. The skins are entered into a weak solution of the hypochlorite,
-and left until the hair is decolorized; then after removing, they are
-passed through a dilute acid, and subsequently through a weak solution of
-sodium thiosulphate in order to remove all traces of the hypochlorite.
-This method causes the hair to acquire a harsh feel, and the yellow
-color is never entirely eliminated. The hair, however, possesses a
-great affinity for certain types of dyestuffs, and it is only when
-these particular classes of dyes are to be applied to the furs, that the
-hypochlorite bleach is used. (See dyeing with Acid colors).
-
-The various oxidation methods of bleaching are supposed to change the
-coloring matter of the hair into an entirely different and colorless
-compound which cannot return to its original form. The bleach is therefore
-permanent.
-
-In common practise, the sulphurous acid, and the peroxide of hydrogen
-methods are the two chiefly employed in bleaching processes. Sulphurous
-acid is used to bleach the cheaper kinds of furs, while peroxide of
-hydrogen is applied to the finer furs.
-
-Whichever process is used, it is customary to give the bleached skins a
-subsequent "blueing," by passing them through a very weak solution of a
-blue or violet dye, such as indigo-carmine, crystal violet, alkali blue
-or ultramarine. The furs are then dried and finished off as usual. In drum
-cleaning white furs, gypsum or white sand, or sometimes even talc are used
-with the sawdust, or occasionally alone without the sawdust.
-
-
-
-
-BIBLIOGRAPHY
-
-
-  Allen "Commercial Organic Analysis"
-
-  Armour, B. R. "Fur Dressing and Dyeing" 1919
-
-  ---- Color Trade Journal, Vol. 1, p. 51-53
-
-  ---- Jour. Amer. Leather Chemists' Assn., Vol. 13, p. 63-69.
-
-  Belden, A. L. "Fur Trade in America" 1917
-
-  Beltzer, F. J. G. "Industrie des Poils et Fourrures, etc." 1912
-
-  ---- Revue Generale des Matieres Colorantes, Vol. 12, 1908
-
-  Bennett, H. G. "Manufacture of Leather" 1910
-
-  Bertram, P. Deutsche Faerber-Zeitung 1895-96 Heft 17, p. 266
-
-  Bird, F. J. "American Practical Dyers' Companion" p. 241-245
-
-  Boerner, H. Kunststoffe, 1912 p. 223
-
-  Brevoort, H. L. "Fur Fibres as shown in the Microscope" 1886
-
-  Bucher, B. "Geschichte der technischen Kuenste" 1875-1893
-
-  Cubaeus, P. "Das Ganze der Kuerschnerei" 1912
-
-  Davis, C. T. "Manufacture of Leather"
-
-  Erdmann, E. Deutsche Faerber-Zeitung 1894-95 Heft 21, p. 337
-
-  ---- Zeitschrift fuer angewandte Chemie, 1895, Heft 14
-
-  ---- Zeitschrift fuer angewandte Chemie, Heft 35, 1905
-
-  ---- Berichte, 1904, 37, p. 2776, 2906
-
-  Farrell, F. J. "Dyeing and Cleaning" 1912
-
-  Fleming, L. "Practical Tanning" 1916
-
-  Fougerat, L. "La Pelleterie dans l'antiquite, la prehistoire, etc."
-
-  Gardner, W. M. "Wool Dyeing" 1896
-
-  Grandmougin, E. Zeitschrift fuer Farben-Industrie, 1906, 5, p. 141
-
-  Gruene, E. Deutsche Faerber-Zeitung, 1895-96 Heft 13, p. 197
-
-  Halle "Werkstaette der heutigen Kuenste," 1762, Vol. 2, p. 317
-
-  Hartwig, O. L. "Sprengler's Kuenste und Handwerke," 1782
-
-  Hausman, L. A. Scientific Monthly, Jan. 1920; March, 1921
-
-  ---- Natural History, Vol. 20, 4, 1920
-
-  ---- American Journal of Anatomy, Sept. 1920
-
-  ---- American Naturalist, Nov.-Dec. 1920
-
-  Hayes, A. H. National Cleaner and Dyer, Nov. 1920, p. 55-57
-
-  Jacobson, "Schauplatz der Zeugmanufacturen" p. 493
-
-  Jones, J. W. "Fur Farming in Canada" 1913
-
-  Knecht, Rawson & Loewenthal "Manual of Dyeing" 1916
-
-  Kobert, R. "Beitrage zur Geschichte des Gerbens und der
-      Adstringentien" 1917
-
-  Koenig, F. Zeitschrift fuer angewandte Chemie, 1914, Vol. 1, p. 529
-
-  Lamb, J. W. Jour. Soc. Dyers & Colourists Dec. 1905, p. 323
-
-  Lamb, M. C. "Dressing of Leather" 1908
-
-  ---- Jour. Soc. Dyers & Colourists 1913, 29, p. 160-165
-
-  Larish & Schmid "Das Kuerschner Handwerk" 1-3
-
-  Laut, A. C. "The Fur Trade of America" 1921
-
-  Lightfoot, J. "The Chemical History & Progress of Aniline Black"
-      1871
-
-  Mairet, E. M. "A Book on Vegetable Dyes" 1916
-
-  Martin, G. "Industrial Organic Chemistry"
-
-  Matthews, J. M. "Application of Dyestuffs" 1920
-
-  Mayer, A. "Die Faerberei in der Werkstaette des Kuerschners"
-
-  Mierzinski, S. "Die Gerb und Farbstoffextrakte"
-
-  Noelting & Lehne "Anilin-Schwarz" 1904
-
-  Perkins & Everest "Natural Organic Coloring Matters" 1918
-
-  Petersen, M. "The Fur Traders & Fur-Bearing Animals" 1920
-
-  Poland, H. "Fur-Bearing Animals in Nature and Commerce"
-
-  Proctor, H. "Leather Industries Laboratory Book"
-
-  ---- "Tanning"
-
-  ---- "Making of Leather"
-
-  Schlottauer, E. Deutsche Farber-Zeitung 1911, Heft 20, p. 397
-
-  ---- Deutscher Faerber-Kalender 1911, p. 65
-
-  ---- Leipziger Faerber-Zeitung 1909, p. 441
-
-  Schmidt, C. H. "Handbuch der Weissgerberei"
-
-  Setlik, B. Deutsche Faerber-Zeitung 1901, p. 213
-
-  Smith, R. W. Color Trade Journal Vol. 3, Sept. 1918, p. 304-310
-
-  ---- Textile Recorder, Vol. 36, p. 292-293, Dec. 1918
-
-  ---- Revue Generale des Matieres Colorantes, Vol. 23, p. 32-36
-
-  Stevenson, C. H. "U. S. Fish Commission Report 1902-1903", Bulletin
-      No. 537
-
-  Stickelberger, E. "Geschichte der Gerberei" 1915
-
-  Strasser "Chemische Faerberei der Rauchwaren" 1879
-
-  Ullmann "Enzyklopedie der technischen Chemie"
-
-  Villon, A. M. "Traite pratique de la fabrication des cuirs, etc."
-      1900
-
-  Werner, H. "Die Kuerschnerkunst" 1914
-
-  ---- "Das Faerben der Rauchwaren" 1914
-
-  Whittaker, C. M. "Dyeing with Coal Tar Dyes" 1919
-
-  Wiener, F. "Weissgerberei" 1877
-
-  Witt-Lehman "Chemische Technologie der Gespinst-Fasern" 1910
-
-  Zeidler, H. "Die moderne Lederfabrikation" 1914
-
-
-
-
-INDEX
-
-
-  Acetate, aluminum, 118
-
-  ---- chromium, 120
-
-  ---- copper, 120
-
-  ---- ferrous, 119
-
-  ---- lead, 126
-
-  Acetic acid, 112
-
-  Acid dyes, 174
-
-  Acids, action of, on hair, 29
-
-  ---- ---- on skin, 26
-
-  After-treatment with copper, 168
-
-  Alaska fox imitations, 143
-
-  Alkaline aluminum mordants, 122
-
-  ---- chromium mordants, 123
-
-  ---- iron mordants, 123
-
-  Alum, 32, 53, 118
-
-  ---- chrome, 57
-
-  ---- -chrome tans, 64
-
-  ---- tans, 54, 56
-
-  Aluminum acetate, 118
-
-  ---- mordants, 118
-
-  ---- sulphate, 53, 118
-
-  Ammonia, 110
-
-  Ammonium sulphide, 126
-
-  Aniline black, 144
-
-  ---- ---- by dip process, 154
-
-  ---- ---- chemistry, 145
-
-  ---- ---- Green's process for, 152
-
-  ---- ---- nature of, 144
-
-  ---- ---- One-bath, 149
-
-  ---- ---- Oxidation, 150
-
-  ---- ---- processes, 149
-
-  ---- ---- ungreenable, 148
-
-  Aniline oil, 145
-
-  Astrachan 5, 7, 12
-
-
-  Bacteria, 51
-
-  Badger, 7
-
-  Ball-drum, 62
-
-  Bandrowski's base, 164
-
-  Basic dyes, 171
-
-  Beam, 38
-
-  Beaming, 38
-
-  Bear, black, 5, 7
-
-  ---- brown, 5, 8
-
-  ---- white, 8
-
-  ---- ---- bleaching of, 179
-
-  Beating furs, 79
-
-  Beaver, 5, 8, 25, 83, 94
-
-  Beechwood ashes, 108
-
-  Bichromate of soda, 121, 147
-
-  Black, aniline, 144
-
-  ---- ---- by Green's process, 152
-
-  ---- ---- chemistry of, 145
-
-  ---- ---- nature of, 144
-
-  ---- ---- One-bath, 149
-
-  ---- ---- Oxidation, 150
-
-  ---- ---- ungreenable, 148
-
-  Black, diphenyl, 152
-
-  ---- logwood, 139
-
-  ---- on Chinese goats, 141
-
-  ---- on lambs, 141
-
-  ---- on raccoon, 130
-
-  ---- on skunk, 130
-
-  ---- on wolf, 130
-
-  Bleaching of furs, 179
-
-  Blending, 91, 104
-
-  Blue-grey on white furs, 142
-
-  Blueing, 184
-
-  Blue salt, 120
-
-  ---- vitriol, 119
-
-  Borax, 39, 58
-
-  Brasilein, 135
-
-  Brasilin, 135
-
-  Brazilwood, 135
-
-  Bright shades on furs, 171
-
-  Broadtail, 8, 12
-
-  ---- dyeing of, 139
-
-  Brown on Thibet sheep, 169
-
-  ---- with natural dyes, 142
-
-  Brush process, 98
-
-  Brushes used in dyeing, 100
-
-  Butter, 60, 63
-
-
-  Cage, 80
-
-  Cageing, 80
-
-  Campeachy wood, 133
-
-  Caracul, 8, 12
-
-  ---- dressing of, 53
-
-  Caracul, dyeing of, 140
-
-  Carnivorous animals, furs of, 37
-
-  Cased skins, 36
-
-  Castor oil, 60, 63
-
-  Cat, civet, 5, 8
-
-  ---- house, 8
-
-  Caustic soda, 44, 110, 113
-
-  Centrifugal machine, 40
-
-  Chamber drying, 73
-
-  Chamois dressing, 31
-
-  ---- tan, 49, 58, 61
-
-  Characteristics of tans, 65
-
-  Chestnut extract, 133
-
-  Chinchilla, 5, 6, 8, 94
-
-  ---- blending of, 91, 104
-
-  Chinchillone, 9
-
-  China goat, black on, 141
-
-  Chlorates, 147
-
-  Chloride of lime, 174
-
-  ---- ---- bleach, 184
-
-  Chrome acetate, 120
-
-  ---- alum, 57, 120
-
-  ---- colors, 176
-
-  ---- -copper mordant, 167
-
-  ---- -formaldehyde tan, 64
-
-  ---- tans, 57, 174
-
-  Chromium mordants, 120, 166
-
-  ---- ---- alkaline, 123
-
-  ---- salts in tanning, 53
-
-  Cleaning pelts, 40
-
-  Coal tar colors, 171
-
-  Cocoanut oil, 60
-
-  Cod-liver oil, 60
-
-  Collagen, 25
-
-  Colloidal solutions, 48
-
-  Combination tans, 49, 64
-
-  Conveying dyed skins, 104
-
-  Conveyor drying, 73
-
-  Copper acetate, 119
-
-  ---- mordants, 119, 166
-
-  ---- salts, 109
-
-  ---- ---- after-treatment with, 168
-
-  ---- sulphate, 119
-
-  Copperas, 119
-
-  Copper-iron mordant, 167
-
-  Coriin, 21
-
-  Corium, 21
-
-  Cortex, 23
-
-  Cottonseed oil, 60, 63
-
-  Cuba wood, 134
-
-  Cutch, gambier, 65, 135
-
-  Cuticle, 23
-
-
-  Davy, Sir Humphrey, 47
-
-  Degreasing furs, 179
-
-  Diphenyl black, 152
-
-  Dip process, 98
-
-  Dressing of lambs, 52
-
-  ---- ---- rabbits, 54
-
-  ---- ---- moles, 54
-
-  Drum, 80
-
-  Drum-cleaning, 105
-
-  Drumming, 76
-
-  Drying-oils, 60
-
-  Drying skins, 71
-
-  Durability of furs, 5
-
-  Dyeing furs at higher temperatures, 174
-
-  Dyeing of imitations, 93
-
-  ---- ---- novelty shades, 92
-
-  ---- with aniline black, 144
-
-  ---- ---- coal tar colors, 171
-
-  ---- ---- mineral colors, 125
-
-  ---- ---- oxidation colors, 155
-
-  ---- ---- vegetable colors, 128
-
-
-  Egg-yolk, 63
-
-  Emeraldine, 145
-
-  Enzymes, 51
-
-  Epidermis, 21
-
-  Erdmann, 155
-
-  Ermine, 5, 9
-
-  ---- bleaching of, 179
-
-
-  Fahrion, 48
-
-  Fat-glands, 21
-
-  Fats, animal, 59
-
-  Fermentation, 51
-
-  Ferrous acetate, 119
-
-  Ferrous sulphate, 119
-
-  Finishing dyed furs, 104
-
-  Fisher, 9
-
-  Fitch, 9, 94
-
-  Flat skins, 36
-
-  Fleshing, 41
-
-  ---- knife, 38, 42
-
-  ---- machines, 42
-
-  Flesh side, 22, 37
-
-  Formaldehyde, 63
-
-  ---- -chrome tan, 64
-
-  ---- tans, 49, 63
-
-  Formic acid, 44, 50
-
-  ---- ---- as soaking agent, 39
-
-  Fox, black on, 140
-
-  ---- blue, 9
-
-  ---- cross, 4, 10
-
-  ---- grey, 10
-
-  ---- kit, 10
-
-  ---- red, 4, 5, 10
-
-  ---- ---- dyed imitation silver fox, 137
-
-  ---- silver, 4, 10
-
-  ---- ---- imitations, 137, 143
-
-  ---- white, 11, 94
-
-  ---- ---- bleaching of, 179
-
-  French seal dye, 138, 144
-
-  Furamine dyes, 162
-
-  Fur beating machine, 80
-
-  Fur dressing, 30
-
-  Fur dyeing, 91
-
-  ---- ---- difficulties of, 95
-
-  ---- ---- with aniline black, 144
-
-  ---- ---- with coal tar colors, 171
-
-  ---- ---- with mineral colors, 125
-
-  ---- ---- with oxidation colors, 155
-
-  ---- ---- with vegetable colors, 128
-
-  Fur-hair, 24
-
-  Furriers' guilds, 34, 90
-
-  Furrol dyes, 166
-
-  Furs, colors of, 3
-
-  ---- description of, 7
-
-  ---- durability of, 5
-
-  ---- of carnivorous animals, 37
-
-  ---- of herbivorous animals, 37
-
-  ---- quality of, 3, 4
-
-  ---- uses of, 1
-
-  ---- valuation of, 6
-
-  ---- weight of, 5
-
-  Fustic, 134
-
-  ---- shades with, 135
-
-
-  Gall-nuts, 128, 132
-
-  Gambier cutch, 65, 135
-
-  Gelatine, 1, 25, 47, 48
-
-  Genet, 5
-
-  Glycerine, 63
-
-  Goat, 5, 11
-
-  ---- logwood black on, 141
-
-  Green's process for aniline black, 152
-
-  Grey-blue on white furs, 142
-
-  Ground water, 87
-
-  Guard-hair, 24
-
-  Guilds, furriers', 34, 90
-
-
-  Hair, 22
-
-  ---- action of acids on, 27
-
-  ---- action of alkalies on, 28
-
-  ---- action of salts on, 28
-
-  Hamster, 3, 11
-
-  Hardness of water, 87
-
-  Hare, 5, 11, 94
-
-  ---- black on, 140
-
-  ---- blue-grey on, 142
-
-  ---- lynx dye on, 126
-
-  ---- stone marten imitation on, 126
-
-  Hematein, 133
-
-  Hematoxylin, 133
-
-  Herbivorous animals, furs of, 37
-
-  Hudson seal, 144
-
-  Hydro-extraction, 40
-
-  Hydrogen peroxide, 168
-
-  ---- ---- bleaching with, 182
-
-  Hydrosulphite bleach, 181
-
-  Hypochlorites, 184
-
-
-  Imitations, dyeing of, 93
-
-  Iron mordants, 119, 167
-
-  Iron pyrolignite, 119
-
-  Iron salts in tanning, 53
-
-  Iron tan, 58
-
-  Iron vitriol, 119
-
-
-  Kangaroo, 12
-
-  Keratin, 25
-
-  Kicker, 61
-
-  Killing, 98, 106
-
-  ---- formulas, 108
-
-  ---- nature of, 107
-
-  ---- purpose of, 106
-
-  ---- by brush process, 111
-
-  ---- by dip process, 111
-
-  ---- with caustic soda, 113
-
-  ---- with lime, 112
-
-  ---- with soda, 112
-
-  Knapp, 46, 57
-
-  Knife, beaming, 38
-
-  ---- shaving, 38
-
-  ---- fleshing, 38
-
-  Kolinsky, 5, 12
-
-  Krimmer, 5, 12, 13
-
-
-  Lactic acid, 44, 51
-
-  Lactic acid fermentation, 50
-
-  Lambs, 12
-
-  ---- dressing of, 50, 53
-
-  ---- dyeing of, 92, 140, 141, 142
-
-  Lard, 60
-
-  Lead, acetate, 126
-
-  Lead sulphide dye, 126
-
-  Leather, definition of, 48
-
-  ---- dressing of, 30
-
-  Leopard, 5, 13, 94
-
-  ---- tanning of, 43
-
-  Lima wood, 135
-
-  Lime, 108, 110, 112
-
-  Linseed oil, 60
-
-  Litharge, 109
-
-  Loft drying, 72
-
-  Logwood, 133
-
-  ---- blacks, 139
-
-  ---- shades with, 134
-
-  Lynx, 5, 13
-
-  ---- imitation on rabbit and hare, 126
-
-  Luster of hair, 23
-
-
-  Machines used in brush dyeing, 102
-
-  ---- ---- dip dyeing, 103
-
-  Marmot, 14, 68, 94
-
-  Marten, blending of, 91, 104
-
-  Marten, baum, 5, 14
-
-  ---- stone, 5, 14
-
-  ---- ---- imitation, 126
-
-  Medulla, 22
-
-  Meunier, 46
-
-  Mineral colors, 125
-
-  ---- oils, 59, 63
-
-  ---- tans, 49, 53
-
-  Mink, 5, 14, 68, 94
-
-  Mole, 5, 15
-
-  ---- tanning of, 54
-
-  Monkey, 15
-
-  Mordanting, 98, 114
-
-  Mordants, alkaline, 121
-
-  ---- aluminum, 118
-
-  ---- chrome-copper, 167
-
-  ---- chromium, 120, 166
-
-  ---- copper, 119, 166
-
-  ---- copper-iron, 167
-
-  ---- iron, 119, 167
-
-  ---- tin, 121
-
-  Mucines, 25
-
-  Muskrat, 5, 15, 68, 94
-
-  ---- imitation seal on, 144, 169
-
-
-  Neats-foot oil, 60, 63
-
-  Neradol D., 64
-
-  Nigraniline, 147
-
-  Non-drying oils, 60, 63
-
-  Novelty shades, dyeing of, 92
-
-  Nutgalls, 33, 132
-
-  Nutria, 5, 15, 94
-
-
-  Oiling, 62, 77
-
-  Oils, drying, 60
-
-  ---- non-drying, 50
-
-  ---- partially-drying, 60, 63
-
-  Olive oil, 60
-
-  One-bath aniline black, 149
-
-  Opossum, 5, 15, 68
-
-  ---- black on, 140
-
-  ---- skunk imitation on, 138
-
-  ---- seal imitation on, 144
-
-  Otter, River, 5, 16, 94
-
-  ---- Sea, 5, 16
-
-  Over-hair, 24
-
-  Oxidation aniline black, 150
-
-  ---- colors, 155
-
-  ---- ---- shades with, 165
-
-
-  Para-amido phenol, 153, 157
-
-  Para-phenylene diamine, 153, 157, 162
-
-  Partially-drying oils, 60, 63
-
-  Pelage, 2
-
-  Pelt, 2
-
-  Pernambuco wood, 135
-
-  Peroxide of hydrogen, 168, 182
-
-  Peroxides, 182
-
-  Persian lamb, 5, 12
-
-  ---- ---- dressing of, 50, 53
-
-  ---- ---- dyeing of, 139
-
-  Physical theories of tanning, 47
-
-  Pickle, 49
-
-  Pigment granules, 23
-
-  Pony, Russian, 5, 16
-
-  Potassium permanganate as a dye, 127
-
-  ---- ---- as a bleach, 183
-
-  Protective-hair, 24
-
-  Pyrolignite of iron, 119
-
-
-  Quercitron, 135
-
-  Quinone di-imine, 163
-
-
-  Rabbit, 6, 17, 94
-
-  ---- imitation seal on, 144
-
-  ---- lynx imitation on, 126
-
-  ---- sable imitation on, 168
-
-  ---- stone marten imitation on, 126
-
-  ---- tanning of, 54, 65
-
-  Raccoon, 6, 17
-
-  ---- black on, 140
-
-  ---- skunk imitation on, 170
-
-  Rain water, 86
-
-  Red fox, dyed as silver fox, 137
-
-  Redwood, 135
-
-  Rodol colors, 165
-
-  Russian tan, 51
-
-
-  Sable, 6, 94
-
-  ---- American, 17
-
-  ---- blending of, 91, 104
-
-  ---- imitation on rabbit, 168
-
-  ---- Russian, 18
-
-  Salammoniac, 109
-
-  Salt, 32, 49
-
-  ---- -acid tan, 49
-
-  ---- -water soak, 39
-
-  Salts, neutral, 54
-
-  ---- basic, 54, 115
-
-  Sawdust in drum-cleaning, 80
-
-  "Schrot-beize," 50
-
-  Seal, 6, 18, 94
-
-  ---- fur, 18
-
-  ---- dyeing of, 92, 144
-
-  ---- hair, 19
-
-  ---- imitation on muskrat, 138, 169
-
-  ---- -oil, 60
-
-  Shearing, 82
-
-  ---- machine, 84
-
-  Shrinking-point of skins, 66
-
-  ---- effect of chemicals on, 67
-
-  Silver fox imitations, 137, 143
-
-  Skin, 21
-
-  ---- action of acids on, 26
-
-  ---- action of alkalies on, 27
-
-  Skunk, 6, 19, 94
-
-  ---- imitation on opossum, 138
-
-  ---- ---- on raccoon, 170
-
-  Soaking skins, 39
-
-  Soda ash, 110, 112
-
-  Sodium bichromate, 121, 166
-
-  ---- bisulphite, 127, 181
-
-  ---- chloride, 49
-
-  ---- peroxide, 182
-
-  ---- sulphite, 181
-
-  Soft water, 87
-
-  Softening skins, 38
-
-  Souring, 113
-
-  Squirrel, 6, 19
-
-  Staking, 78
-
-  Stannous chloride, 121
-
-  Stiasny, 64
-
-  Stone marten imitation, 126
-
-  Stretching, 78
-
-  ---- machines, 78
-
-  Sugar of lead, 126
-
-  Sulphonated oils, 63
-
-  Sulphuric acid, 49
-
-  Sulphurous acid bleach, 180
-
-  Sumach, 128, 133
-
-  ---- tanning with, 33
-
-  Surface water, 87
-
-  Sweat-glands, 22
-
-
-  Tallow, 60
-
-  Tanned furs, qualities of, 48
-
-  Tanning methods, comparison of, 65
-
-  Tannins, 32, 132
-
-  Tiger, 19
-
-  Top-hair, 24
-
-  Train oils, 63
-
-  Tramping machine, 61
-
-  Turmeric, 136
-
-
-  Under-hair, 24
-
-  Under-wool, 24
-
-  Ungreenable aniline black, 148
-
-  Unhairing, 82
-
-  ---- machine, 83
-
-  Ursol dyes, 157, 165
-
-
-  Vanadium compounds, 147
-
-  Vat dyes, 177
-
-  Vegetable dyes, 128, 136
-
-  ---- oils, 59
-
-  ---- tans, 49, 65
-
-  Verdigris, 120
-
-
-  Water, hard, 87
-
-  ---- soft, 87
-
-  Whale oil, 60
-
-  White fox, bleaching of, 179
-
-  Wolf, 6, 19
-
-  Wolverine, 6, 20
-
-  Wombat, 20
-
-  Wood dyes, 128
-
-
-  Yellow wood, 134
-
-
-
-
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-
-
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-engineering and scientific books in the United States. The technical
-literature of every trade is well represented, as is also the literature
-relating to the various sciences, both the books useful for reference as
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-
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-
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-       *       *       *       *       *
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-
-Transcriber's Notes:
-
-Punctuation has been standardised--in particular, missing periods
-and quotation marks have been supplied where obviously required.
-Three entries in the bibliography were located out of alphabetical
-order, and have been moved accordingly (Fougerat, Lamb, Martin).
-All other original errors and inconsistencies have been retained,
-except as follows:
-
-  Page 7:   changed Enclyclopedia to Encyclopedia
-            (in Encyclopedia Britannica, 11th Ed.)
-  Page 20:  changed Kaola to Koala
-            (Koala or Australian Bear.)
-  Page 62:  changed partiular to particular
-            (on the particular fur treatment)
-  Page 67:  changed degress to degrees
-            (almost 10 degrees higher than)
-  Page 73:  changed samewhat to somewhat
-            (based on a somewhat different)
-  Page 93:  changed imitatations to imitations
-            (dyeing of imitations to a great)
-  Page 101: changed diagramatically to diagrammatically
-            (and B shows diagrammatically, machines)
-  Page 128: changed conjuction to conjunction
-            (which in conjunction with certain)
-  Page 136: changed curcuma to Curcuma
-            (stem of the Curcuma tinctoria,)
-  Page 137: changed simutaneously to simultaneously
-            (and dye simultaneously; and third)
-  Page 140: changed atmopheric to atmospheric
-            (aid of the atmospheric oxygen.)
-  Page 142: changed followlowing to following
-            (successively in the following baths:)
-  Page 149: changed ozidizing to oxidizing
-            (is also an oxidizing agent and)
-  Page 154: changed dryig to drying
-            (several times, drying each time at)
-  Page 161: changed manufacurers to manufacturers
-            (Other manufacturers of coal-tar)
-  Page 170: changed Racoon to Raccoon
-            (_Imitation Skunk on Raccoon_)
-  Page 185: changed Werkstatte to Werkstaette
-            (Halle "Werkstaette der heutigen)
-  Page 185: changed Gerben to Gerbens
-            (Geschichte des Gerbens und der)
-  Page 185: changed Astringentien to Adstringentien
-            (und der Adstringentien" 1917)
-
-
-
-
-
-End of the Project Gutenberg EBook of Principles and Practice of Fur
-Dressing and Fur Dyeing, by William E. Austin
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