FOR MERCHANTS AND MANUFACTURERS OF LEATHER AND LEATHER GOODS
The purpose of the department of the Guide in which this chapter
appears, addressed to persons engaged in certain important occupations,
is not only to show them how Britannica-reading will enlarge their
knowledge of some aspects and relations of their business, but also to
show how Britannica-reading will help them to realize the importance of
_educating the general public_ in regard to that business. This
education of the public is not necessarily confined to advertising,
although the best form of advertising that can be used by anyone who
sells a good article, or an article that is good at its price, is
probably to tell the public what it really is and how it is really made.
In the direct personal intercourse between salesman and purchaser there
is opportunity for the imparting of information which, if it possesses
genuine interest, will be gladly received and will stimulate trade. Mere
praise of an article is uninteresting and unconvincing; while facts that
explain _why_ that article is adapted to a particular use, and _why_ it
is better than another article sold at a lower price will always receive
attention.
[Sidenote: About Selling Leather Goods]
All this is especially true of leather goods, for the public ignorance
on the subject of leather is abysmal. Nothing is more universally used,
yet ninety-nine out of a hundred who use it not only do not know what
lies beneath the surface of it, but do not know that there is any
difference in value between a natural grain surface and a mechanically
grained false surface, and it is quite certain that nearly all the men
and women who walk out of a store after buying skiver would be
nonplussed if they were asked whether the upper or lower part of a split
skin was the best.
Both the leather merchant and the public would be delighted to hear some
of the curious things that the Britannica tells about leather, which is,
from any point of view, one of the most interesting of all commodities;
although few of those who use it, and perhaps as few of those who deal
in it, ever stop to think how curious a relation there is between the
original nature of the material and the qualities of the finished
product. In cattle and sheep, the hide is a garment that covers every
part of the body but the feet. Adapted to our own use, its most
important service as a garment is to cover our feet. It is so far a
natural product that no imitation of it possesses any of its chief
merits, and yet so far an artificial product that when the hide has been
removed from an animal, it requires treatment in order that it may not
lose the flexibility which makes it, for a thousand purposes, more
valuable than wood or metal, and in order that it may not decay.
[Sidenote: What Skin Is]
Skin is waterproof because its surface consists of scales, and although
in most quadrupeds, as in man, these scales are so small as to be
invisible, they will so resist the entrance of any tan liquor or other
preservative fluid that they must be scraped away before the skin can be
treated. Under these horny scales there is a layer of soft cells, and
under this a membrane which makes the natural grain surface of leather.
Under this, again, lies the “true” skin, in In the upper of these two,
the white fibres lie parallel with the grain. In the lower, the white
fibres, which are here coarser, lie in bundles, bound together by yellow
fibres, so that this layer is really a woven fabric. The spaces in the
weave are filled with a soft jelly, and the fibres do not multiply among
themselves, as cells do, but are developed, as they are needed, from
this jelly. Tan liquor has the peculiar property of converting this
jelly into a “leathery” substance, which although it does not then
assume the shape of fibres, becomes nearly as tough as the fibres
themselves, and thus makes leather more solid and stronger than the
original skin; and the virtue of leather depends largely on the presence
of this jelly. [Sidenote: Naturally Woven Fibres] two layers. The body
of an old bull will have absorbed it, just as fat is absorbed in old
age, so that the spaces in the weave of the fibre are left vacant, and
(as the scaly outer surface of the skin has been scraped away to admit
the tan liquor) any water with which the hide comes into contact will be
soaked up. That is why old bull leather is not waterproof and is lacking
in substance. Again, the weave of this innermost layer of skin, lying
next to the flesh, varies in different animals. In sheepskin the fibres
are very loosely woven, and for this reason great care is needed in
preparing the leather, and when the skin is split, the under half is
only fit for the light usage to which “chamois” leather is restricted.
But however the quality, surface or thickness of the skin may differ,
its true structure is the same in all animals used for leather, save the
horse, which is exceptional in possessing, over the loins, a third skin,
very closely woven and very greasy, which makes horsehide taken from
this part of the body peculiarly waterproof, pliable and durable.
As you are in the leather business, you probably knew all these facts
already, but perhaps they were not arranged in your mind in a form in
which you could explain them to others as clearly as you will be able to
do after reading the articles in the Britannica from which this general
statement is summarized. And when you are reading about any other
business, or about any other subject of any kind, you will find that the
Britannica _goes to the root of the subject_ in the same thorough way in
which it deals with the fibres and the jelly that make up the substance
of leather. Now for the articles in detail—or the principal ones; the
others are sufficiently indicated by the list at the end of this
chapter.
SKIN (Vol. 25, p. 188), by Dr. F. G. Parsons, vice-president of the
Anatomical Society of Great Britain and Ireland, with illustrations from
microscopic enlargements, covers the comparative anatomy of the skin in
all groups of animals, and the process of skin development in the
embryo. The articles mentioned in the chapter _For Stock-Raisers_ tell
you about the domestic animals whose hides are chiefly used for leather.
The chapter on _Zoology_ in this Guide gives a list of the articles on
the other animals whose skins are tanned for fancy leathers. The main
article LEATHER (Vol. 16, p. 330), equivalent to 50 pages of this Guide,
is by Dr. James G. Parker, principal of the Leathersellers’ Technical
College, London, and author of _Principles of Tanning_ and other
standard trade text-books. After explaining the distinctions between
tanned, tawed, and chamoised leathers, it takes up the subject of
sources and qualities of hides and skins, and describes the structure of
skin in relation to the finished product. The characteristics and
peculiarities of hides and skins from different parts of the world are
thoroughly explained. We learn why hides from animals bred in
mountainous districts are the best, and where the finest sheep- and
goat-skins come from.
[Sidenote: Processes of Tanning]
_Tanning Materials_ is the subject of the next section. These are
classified into pyrogallols, catechols, and subsidiary materials; and
the article describes their composition and preparation by grinding,
with explicit directions for their testing, including the latest
official method of the International Association of Leather Trades
Chemists. The processes of making heavy leathers are next discussed. We
learn the many ways of cleaning, softening, depilating, and
fellmongering (or dewooling) by liming, rounding and scudding, and
finally the process of actual tanning in its three steps of colouring,
handling, and laying away. In connection with depilation, it is
interesting to note that it has been discovered that it is not the lime
but the action of bacteria in the lime which causes the hair to fall
out. The finishing of sole leather, harness leather and other grades is
explained, also the theory of the formation of the “bloom” and its
removal, as well as the process of “scouring.” The art of _Currying_ has
a section to itself, and the preparations for tanning or dressing hides
for trunks and suit cases by bating, puering, scudding, plumping,
drenching and splitting, receive detailed attention. The tanning of
light leathers, and all the varieties of basils, skivers, Russia
leather, seal, alligator, snake, frog and kangaroo leathers, Japan and
enamel leathers are fully treated. _Tawing_, _Wooling_, _Dressing_,
_Chrome Tanning_, _Combination Tannages_, _Oil Tanning_ (Chamoising),
_Preller’s Helvetia_ or _Crown Leather_, _Transparent Leather_,
_Parchment_, _Tar and Peat Tanning_, _Dyeing_, _Staining_ and
_Finishing_, _Glove Leathers_, and _Bookbinding Leathers_ are some of
the other sections of this excellent treatise. LEATHER, ARTIFICIAL (Vol.
16, p. 345) is a separate article.
[Sidenote: Chemistry of Leather Manufacture]
TANNIN, or TANNIC ACID (Vol. 26, p. 399) is a general account of the
vegetable products which have the property of converting raw hide into
leather. Specific information about the materials from which the
pyrogallol tannins are obtained will be found under MYROBALANS (Vol. 19,
p. 114), CHESTNUT (Vol. 6, p. 112), DIVIDIVI (Vol. 8, p. 332), SUMACH
(Vol. 26, p. 70), OAK (Vol. 19, p. 931), GALLS (Vol. 11, p. 422) a full
and interesting account of the insect produced vegetable excrescence
which yields a high percentage of tannin, by Francis H. Butler, of the
Royal School of Mines; and WILLOW (Vol. 28, p. 688). For the catechol
tannins see HEMLOCK (Vol. 13, p. 262), CATECHU (Vol. 5, p. 507),
MANGROVE (Vol. 17, p. 572), MIMOSA (Vol. 18, p. 500), LARCH (Vol. 16, p.
211), BIRCH (Vol. 3, p. 958), which yields the empyreumatic oil used in
the preparation of Russia leather, to which the pleasant odor is due.
There are numerous articles in the Britannica on the chemicals used in
the process of tawing, chrome tanning, etc., such as ALUM (Vol. 1, p.
766), ACETIC ACID (Vol. 1, p. 135), GLAUBER’S SALT (Vol. 12, p. 114),
BICHROMATES AND CHROMATES (Vol. 3, p. 912).
[Sidenote: Dyeing]
The chief classes of dyes used for leather are the acid; basic, or
tannic; direct, or cotton; and mordant dyes, and these are described at
great length in a valuable article DYEING (Vol. 8, p. 744), equivalent
to 20 pages of this Guide, by the late J. J. Hummel, professor of
Dyeing, University of Leeds, and Dr. Edmund Knecht, professor of
Technological Chemistry, University of Manchester. The section on the
_Theory of Dyeing_ shows how the dyeing property of a substance depends
upon its chemical composition. Separate articles go more deeply into the
chemistry of dyeing materials used with leather, and some of the more
important of these are SULPHONIC ACIDS (Vol. 26, p. 60), SULPHURIC ACID
(Vol. 26, p. 65), FORMIC ACID (Vol. 10, p. 668), ANTIMONY (Vol. 2, p.
127), TITANIUM (Vol. 26, p. 1017), IRON (Vol. 14, p. 796), LOGWOOD (Vol.
16, p. 922), FUSTIC (Vol. 11, p. 375), BRAZIL WOOD (Vol. 4, p. 463), and
TUMERIC (Vol. 27, p. 474). Comparatively few of the coal-tar colours
have as yet been adapted to leather manufacture, but their
characteristics are discussed in such articles as AZO-COMPOUNDS (Vol. 3,
p. 81), ANILINE (Vol. 2, p. 47), INDULINES (Vol. 14, p. 507), FUCHSINE
(Vol. 11, p. 273), and SAFRANINE (Vol. 23, p. 1000).
[Sidenote: Special Leathers]
PARCHMENT (Vol. 20, p. 798), by Sir E. Maunde Thompson, Principal
Librarian, British Museum, is an interesting historical account of the
skins and their preparation. Their use as writing material was
widespread at a very early period. “The Jews made use of them,” says the
article “for their sacred books, and it may be presumed for other
literature also; and the old tradition has been maintained down to our
own day, requiring the Synagogue rolls to be inscribed on this
time-honoured material.” The difference between parchment and vellum is
explained. SHAGREEN (Vol. 24, p. 769) tells about a species of untanned
leather used for ornamental purposes. It is a curious fact that the
addition of the word “chagrin,” for anxiety or annoyance, to the English
language was due to the unpleasant sensation that came from touching the
rasping surface of this leather. Stamped leather for wall hangings is
described in the section _Stamped Leather_ of the article MURAL
DECORATION (Vol. 19, p. 19), by William Morris and Walter Crane. SHOE
(Vol. 24, p. 992) contains an illustrated section on the _Manufacture of
Leather Shoes_. SADDLERY AND HARNESS (Vol. 23, p. 988), by Cecil
Weatherly, and GLOVE (Vol. 12, p. 135) are treated both from an
historical and a practical point of view. BOOKBINDING (Vol. 4, p. 216),
illustrated, by C. J. H. Davenport, of the British Museum, has a great
deal of interesting information about the leathers used in this art. The
flexible binding, which has been applied for the first time on a large
scale in the new Britannica, originated when vellum instead of paper was
used for books, and it possesses the great advantage that a volume sewed
in this way can be opened flat, and lies flat without being held.
ALPHABETICAL LIST OF ARTICLES AND OF SUBJECTS IN THE ENCYCLOPAEDIA
BRITANNICA OF SPECIAL INTEREST TO THOSE IN THE MANUFACTURE AND SALE OF
LEATHER AND LEATHER GOODS
Acetic Acid
Acid dyes
Aldehyde tanning
Algarobilla
Alligator Leather
Alum
Angols
Aniline
Antimony
Azo Compounds
Barkometer
Basic, or Tannin dyes
Basils
Bates
Bating
Bichromates and Chromates
Birch
Bleaching
Bloom
Bookbinding
Bookbinding Leathers
Bottle-tanning
Brazil Wood
Canaigre
Catechols
Catechu
Chamoising
Chestnut
Chestnut Oak
Chrome Box
Chrome Tanning
Colouring Pits, or Suspenders
Combination Tannages
Crust Stock
Currying Apparatus
Currying Processes
Dash-wheel
Depilation
Direct, or Cotton, Dyes
Dividivi
Dongola Leather
Drenching
Dressing
Drum Dyeing
Dusting Material
Dyeing
Enamel Leather
Erodin
Fatliquoring
Fellmongering, or Dewooling
Finishing
Formic Acid
Frog Skin
Fuchsine
Fustic
Galls
Gambier
Glauber’s Salt
Glazing (Glacé leather)
Glove
Glove Leathers
Grinding Machinery and Leaching
Handlers, or Floaters
Heavy Leathers
Hemlock
Hide Mill, or Double-Acting Stocks
Hide-powders
Hides and Skins
Indulines
Iron
Iron Tannage
Janus Colours
Japan Leather
Kangaroo Leather
Kaspine Leather
Kips
Larch
Leather
Leather, Artificial
Levant Morocco
Liming
Logwood
Mangrove
Mimosa, or Golden Wattle
Mordant dyes
Morocco Leather
Myrobalans
Oak bark
Oak wood
Oil Tanning
Parchment
Payne and Pullman Process
Peat Tanning
Pigskin
Portmanteau
Power Transmission, _Belts_
Preller’s Helvetia or Crown Leather
Puering
Pyrogallols
Quebracho
Roans
Russia Leather
Saddlery and Harness
Safranine
Sammying
Scudding
Seal Leathers
Setting
Shagreen
Shoe
Skin
Skivers
Snakeskin
Splitting Machines
Staining
Sulphonic Acids
Sulphuric Acid
Sumach
Sweating
Tan Liquors
Tanner’s Beam
Tanner’s Hook
Tanner’s Knives
Tannin, or Tannic Acid
Tawing
Tiffany Bate
Titanium
Transparent Leather
Tray Dyeing
Turmeric
Upper Leather
Valonia
Vellum
Vidal Colours
Waxing
Willow
Willow Calf
Tannin Precipitation
Tanning Materials
Tar Tanning
Wilson Scouring Machine
Wool-rug Dressing