The names given to different kinds of leather come sometimes from the character of its surface, that is, from the “grain,” or roughness or corrugation it has; sometimes from the animal it once covered; sometimes from the method of tanning; sometimes from the fact that it is part of a skin which has been split; sometimes from the place or country where it is made or where the animal it once covered lived, and sometimes from a combination of two or more of these.

The subject of the leathers used in bookbinding is a very difficult one. Tanners, dealers and binders, dictionaries, encyclopÆdias and books on tanning disagree with one another as to the proper terms to use in speaking of different kinds of leather. Imitations are many, and very successful. In the list below I have tried to follow the usage of binders; but I am sure no expert would accept it throughout as correct.

With this variety in definition goes a corresponding variety in character in leather of the same name. Different skins tanned in the same way, apparently, and called by the same name by dealers and binders, will wear, some well, some not so well. The only quite definite assertion which can be made is, that of modern leathers, few save the best morocco and pigskin will keep their strength for any length of time in an American library, and morocco and pigskin usually for not much over 20 years.

As the remarks which follow indicate, English leather makers have recently procured leathers guaranteed to be dressed on the lines recommended by the Society of Arts Report. See also the revised report, and the little volume, with samples, called Leather for Libraries by Hulme, Parker and others.

Leathers made from the skins of animals of the same kind, the goat for example, though made by the same process, vary somewhat with the animals’ sex, age when killed, the food on which they lived, the climate in which they matured, and their manner of life, and, if females, with the fact that they have or have not had young. Also, the leather made from the skin of one part of the body differs materially from that made from the skin of another part.

Moreover, some dyes seem to hasten decay, some to retard it. Red seems least hurtful, black the most so; though this difference is probably due more to chemicals used in the preparation of the skin for the dye than to the dye itself. Brown generally stands well; most other colors, except red as stated, do not.

With all these, and other, factors to be taken into consideration it is evident that full knowledge of leather is not given to anyone. In a general way it may be said that good leather cannot be told by name, or looks, or feel; but only by trial. Dealers, even, cannot tell the good from the best.

The sum of all advice is, having found, by your own or others’ tests, that a certain leather is good, use it as long as you can get it. The British museum sets a good example in this. It has in recent years bound many thousands of volumes in morocco made by Meredith-Jones & Sons, Wrexham, Wales, which experience thus far shows to be very good. We have tried it and in the brief trial we have given it, found it excellent.

Dr. J. Gordon Parker, Herold’s Institute, Drummond Road, Bermondsey, England, has made an arrangement with the council of the Library Association of England by which he has become their official examiner of leather and he will test samples for acids, nature of tannage, etc., at reasonable rates.

John Muir & Son, tanners and curriers, Beith, Scotland, offices: 3 Arundel St., Strand, London, W. C., England, prepare pigskin for bookbinding; so do Edw. & Jas. Richardson, Elswick Leather Works, Newcastle-on-Tyne, England.

J. Meredith-Jones & Sons, Ltd., Cambrian Leather Works, Wrexham, Wales, make bookbinders’ leathers guaranteed to be dressed on the lines recommended by the Society of Arts Report, and free from mineral acids. Specialty: Welsh sheep.

Much has been written on the wearing and lasting qualities of leather. The best discussion of the subject is the Report of the committee on leather for bookbinding, made to the Society of Arts, England, and published in its Journal, July 5, 1901. I allude to this report frequently, and for convenience speak of it as “Report ’01.” The committee who made this report found that the leather made today does not last as long as that made 75 years ago. They found that the heat and fumes of gas help to hasten the decay of the leather on books. These factors are more effective in American superheated libraries than in English ones. If books bound in leather are much handled they last longer than if they stand undisturbed on the shelves, because the oil from the hand helps to keep leather soft, pliable, and alive. The committee concluded that no leather, with the sole exception of Niger goat, made by the natives on the river Niger in Africa, and imported just as it leaves their hands, can be fully recommended as free from elements which lead to its early decay. Since this report was published imitations of this leather have been put on the market, and it can no longer be relied upon. We have found it beautiful in color and texture, easy to work and wearing admirably on large and much-used books. But it does not keep clean as well as a good morocco of coarse grain. It is very expensive, and first-class morocco is probably better where strong, enduring leather is advisable which is only on books which are to be much used.

The most important points made in the report of the Society of Arts committee on leather for bookbinding, referred to above, are the following:

Books bound during the last 80 or 100 years show far greater evidence of deterioration than those of an earlier date. Many recent bindings show evidence of decay after so short a period as ten or even five, years. Modern leather is certainly far less durable than old leather.

The most prevalent decay is a red decay, and this may be differentiated into old and new, the old red decay being noticeable up to about 1830, and the new decay since that date.

Another form of deterioration, more noticeable in the newer books, renders the grain of the leather liable to peel off when exposed to the slightest friction. This is the most common form of decay noted in the most recent leathers.

Decay is caused by both mechanical and chemical influences. Of the latter some are due to mistakes of the leather manufacturer and the bookbinder, others to the want of ventilation, and improper heating and lighting of libraries. In some cases inferior leathers are finished (by methods in themselves injurious) to imitate a better class of leathers, and of course where these are used durability cannot be expected. But in the main the injury for which the manufacturer and bookbinder are responsible must be attributed rather to ignorance of the effect of the means employed to give the leather the outward qualities required for binding, than to the intentional production of an inferior article.

Embossing leather under heavy pressure to imitate a grain has a very injurious effect.

The shaving of thick skins greatly reduces the strength of the leather by cutting away the tough fibers of the inner part of the skin.

The use of mineral acids in brightening the color of leather, and in the process of dyeing, has a serious effect in lessening its resistance to decay.

Quite modern leather dyed black seems, in nearly all cases, to have perished, although old black morocco (sixteenth, seventeenth and eighteenth centuries) in good condition is not uncommon.

In a very large proportion of cases the decay of modern sumac-tanned leather has been due to the sulphuric acid used in the dye bath, and retained in the skin.

Tobacco smoke has a darkening and deleterious effect on leather bindings.

Light, and especially direct sunlight and hot air, possess deleterious influences which had scarcely been suspected.

Gas fumes are the most injurious of all the influences to which books are subjected, no doubt because of sulphuric and sulphurous acid they contain. They are especially injurious to books on the upper shelves of a high room.

The importance of moderate temperature and thorough ventilation of libraries cannot be too much insisted on. With proper conditions of ventilation, temperature, and dryness, books may be preserved without deterioration, for very long periods, on open shelves.

On the other hand, as a general rule, tightly fitting glass cases conduce to their preservation.

Leather bindings that have been coated with glair or varnish seem to keep better than those without.

The bookbinder shares, in no small measure, with the leather manufacturer and librarian, the blame for the premature decay of leather bindings.

Books are sewn on too few and too thin cords, and are not firmly laced into the boards. This renders the attachment of the boards to the book almost entirely dependent on the strength of the leather.

The use of hollow backs usually throws too much strain on the joints in opening and shutting the book.

If the headbands are not strong the leather of the back is apt to become torn.

The leather is often made very wet and stretched a great deal in covering, with the result that, on drying, it is further strained, almost to breaking point, by contraction, leaving a very small margin of strength to meet the accidents of use.

The use of oxalic acid for washing backs of books, or of leather for bookbinding, is fatal to durability. Vinegar, even in its pure state, is injurious.

Paste should be used in a fresh condition, otherwise it is liable to undergo an acid fermentation, and to favor the growth of injurious moulds and bacteria.

In all contracts and specifications for bookbinding, the use of East India-tanned goat and sheep, whether retanned or not, should be absolutely forbidden.

It appears to be the general opinion that leather, and especially Russia leather, lasts better on books that are in constant use. This is attributed to the slight amount of grease absorbed by the leather from the hand, and it is suggested that possibly a suitable dressing may be discovered which would have a similar effect to that produced by this grease.

While the leather now used for binding books is less durable than that employed 50 years and more ago, there ought to be no difficulty in providing leather at the present time as good as any previously made.

It is possible to test any leather in such a way as to guarantee its suitability for bookbinding.

A reissue of the report summarized above was published, in cloth, in 1905. It is entered in the list of books at the end of this volume. In this reissue the arrangement of the original report is somewhat modified; a paper on leather dyes and dyeing has been added; the report of the scientific sub-committee has been practically rewritten; many illustrations have been added, some of them colored; 12 samples of leather prepared in accordance with the committee’s conclusions are inserted; and the volume is handsomely printed, and bound in cloth. The reissue, however, does not make necessary any change in the above summary.