Preservation of Leather. Various attempts have been made both by librarians and others to discover some substance which would preserve leather effectually after the book is bound. Some of these attempts have been temporarily successful, but time alone will tell whether leathers are permanently preserved by the treatments used, or whether applications of the preservative must be frequently made. Owing to the fact that in law libraries practically all the books published previous to 1900 were bound in sheepskin, the lasting qualities of leathers is a question that affects law libraries more than any other. Dr. Wire, of the Worcester (Mass.) County Law Library, who has made a careful study of the problem, advises the use of vaseline or some other similar by-product of petroleum well rubbed into the leather with the bare hand and allowed to dry in the air until the leather has absorbed it. Better results were obtained by allowing the volumes to dry in the summer by natural heat instead of artificial heat in the winter. For some books Dr. Wire makes use of a bookbinder's varnish after the softening product has thoroughly penetrated the leather. A full description of the processes may be obtained from Dr. Wire's pamphlet, "Leather preservation," published in 1911.
Some of the disadvantages of Dr. Wire's method are:
1. The necessity of rubbing in the preservative from three to five times, according to the condition of the leather at the time of first treatment.
2. The care necessary to prevent the material used from smearing tables, trucks, floor, shelves and clothing at time of application; also when books are back on the shelves the care required to keep from rubbing against them and the necessity of wiping them off when they are handed to readers.
3. The tendency of books to swell at the back when first treated in this way, demanding extra care lest, in an effort to pull out one book, a whole shelf-full fall to the floor.
4. The repetition of the process after ten years.
It is possible that these drawbacks will be sufficient to dissuade all except the most stout-hearted from using this method of preserving leather. Rebinding in cloth seems to be much more simple and, on the whole, not much more expensive.
The question of a preservative is discussed in the Report of the Society of Arts, from which the following quotation is taken:
Enquiries have frequently been made as to the use of preservative pastes upon old bindings. It has been mentioned that the seasonings of white of egg or blood albumen usually employed in finishing leather have some preservative effect, and no harm can arise from the application of very thin coatings of white of egg. The use of ammonia to thin or preserve the solution must be avoided, but the whites, after thorough beating, may be rendered antiseptic by the addition of a small quantity of camphor, thymol, or some essential oil. Vaseline has been employed as a dressing, and, if otherwise suitable, will no doubt have a preservative effect upon the leather. A very moderate use of the wax, soap, and turpentine preparations made as shoe pastes, is also likely to be beneficial, and no doubt a special preparation might be made on these lines which would be still more suitable. Paraffin wax dissolved in benzine is also harmless, and the surface to which it has been applied takes a good polish with a flannel after drying. Professor Proctor has experimented with a finish introduced by the Berlin Aniline Company some years ago for coloured leathers, with apparently satisfactory results. The preparation is practically a very hard stearine soap with excess of stearic acid, and is made by boiling 8 parts of stearic acid with 1 part of caustic soda and 50 parts of water until thoroughly dissolved, and then adding 150 parts of cold water and stirring till the material sets to a jelly. It is applied very thinly with a sponge or rag, and after thorough drying is polished with a soft brush or flannel. The alkali present in the soap is useful in neutralising any mineral acids contained in the leather. In very acid leathers it has been noticed that the sodium sulphate so formed will sometimes appear upon the surface as a white film, but this is easily removed with a damp cloth, and the surface, after drying, repolished with flannel.
Old books which it is desirable to preserve as long as possible in their original bindings and books which will be used very little may be treated with some form of preservative. If the book is to be much used, it would better be rebound. Dr. Wire's experiments have been carried on exclusively with law books. Whether the same processes could be used on books bound in morocco or pigskin is something that has not yet been determined. Most leather-bound books break first at the joint. The sheep bindings in a law library would show signs of disintegration long before the leather reached the breaking point, whereas the librarian would first notice that morocco was decaying when the leather actually cracked. Once cracked, no amount of preservative would do any good.