Sealskin
Although experiments have been made with it in some English libraries sealskin has never been much used in the United States for library binding. It is made from the skins of the hair seal, the supply coming from all parts of the North Atlantic Ocean. According to Mr. Douglas Cockerell and other binding experts in England, the skin is peculiarly suited for library use. It is reported to be a hard-wearing leather, tough and pliable, even in quality so that no part of the skin must be discarded because too thin or too weak, and possessing a beautiful grain. The price ranges from a point somewhat higher than that of the poorer moroccos to one somewhat lower than the higher prices. Unfortunately it can be easily imitated.
Vellum
Probably no discussion of leather is complete without mentioning vellum, a binding material which does not resemble leather, but which nevertheless is made from calfskin or sometimes from goat skin. It is prepared by the use of lime, and as far as the actual wear on flat surface is concerned, is perhaps better than any leather. It is, however, very susceptible to moisture, which makes it warp; and to light, which makes it hard and brittle. Since it is very hard, does not bend easily and is hard to work, its chief use is on the corners of books to protect them and make them less likely to break or rub. Large libraries have used it somewhat for this purpose, but the use is dying out.
In making a study of leathers it is well to obtain samples of all kinds, including those which are unsuitable for library use, and to examine them carefully, noting the appearance of the grain, thickness of skin, flexibility, and softness of surface. Perhaps more money can be wasted through ignorance of the comparative values of different kinds of leather which it is permissible to use in library binding, than in mismanagement of any other part of binding.
CLOTH
Cloth is fully as important as leather in the economy of binding. Several years ago it was the custom to bind periodicals and other books which were used comparatively seldom in leather, while fiction, juvenile and other books which wore out quickly were bound in cloth. Recently the opposite course has been more favored. Books which receive unusually hard usage and are in the hands of readers constantly are bound in leather; while those which are used seldom, including periodicals, are bound in some kind of cloth. Without doubt the change is a wise one. Even the best of leather disintegrates in time under the action of heat, gas, light, etc., and to-day many a volume bound in leather ten or fifteen years ago has parted from its sides, necessitating rebinding or recovering. Had it been bound in a good quality of cloth it would to-day be in good condition, and probably would remain in good condition for a hundred years. It requires considerable courage to change the binding of a good set of a standard periodical, such as the Atlantic or Harper's, from an attractive half morocco binding to an unattractive buckram. Unquestionably, if economy is an object, the change should be made, except possibly in the case of a library which uses these periodicals daily. Every librarian must decide each case for himself strictly according to the use the set is to receive, always bearing in mind the fact that leather disintegrates with time, whereas cloth does not unless exposed to excessive moisture.
No cloth which is suitable for library use is perfectly satisfactory because it has not the strength of good leather, cannot be used advantageously on very heavy books, soils easily and with use grows soft and flabby, especially along the joints. But on the other hand even those not suitable for libraries which are used by the publisher on cheap books are much better than poor grades of leathers, such as skiver, bock, buffing, etc.
The requisite qualities of a good cloth are:
(a) Endurance when folded back and forth in the same place, so that it may withstand the wear at the joint caused by opening the book.