Open shelves undoubtedly form the ideal resting place for books, since they are not only convenient for access, but also allow a free circulation of air around the volumes. They are, however, often impracticable as affording insufficient protection against dust and dirt, especially in cities, where closed cases are very necessary. No case with movable doors is absolutely dust-proof, but some types very closely approach this desirable state.

Closed cases are, of course, to be preferred with glass doors to reveal a glimpse of the treasures within. They should be set a few inches away from the wall, to permit a free circulation of air around them, and should never be so placed that the books are exposed to direct sunlight or a strong glare, as this will fade or discolor the bindings, particularly green leather, which is very apt to turn brown. The room in which cases are placed should be free from damp, and the windows should be kept closed at night. If the windows admit an excess of sunlight or glare, they are best furnished with yellowish or olive-green glass, which will neutralize any harmful effects of the light on the books. Such colored glass, if "leaded," may be made a very attractive addition to the appearance of the room. Red glass verging toward the orange is equally effective, but less adaptable to the purpose.

A full description of the effects of light on various kinds and colors of leathers will be found in the Report of the Committee on Leather for Bookbindings, London, Bell, 1905. This report also gives the following suggestion for a preservative finish to be used on leather bindings: "Boil eight parts of stearic acid and one part of caustic soda in fifty parts of water, until dissolved. Then add one hundred and fifty parts of cold water and stir until the substance sets into a jelly. Apply this jelly thinly with a sponge or rag and, when it has dried, polish the leather with a soft flannel. If a white film rises to the surface of the leather this can be wiped away with a damp cloth and the leather repolished." A fair supply of this mixture, suitable for small library purposes, can be made by boiling half an ounce (by weight) of the stearic acid, and one sixteenth of an ounce (by weight) of the caustic soda, in three liquid ounces of water and then adding nine liquid ounces of cold water. It is best to stir the mixture gently while cooling; the entire process of preparation will take only a few minutes. If kept for more than a week or two, this mixture may become mouldy. It is better to prepare it only when it can be used on a number of books at once.

Books in closed cases should be removed and thoroughly dusted at least once a year, the tops especially being carefully wiped clean, if gilt, or brushed, if uncut, in either case while holding the book tightly closed. They should be aired at the same time, particularly those not in frequent use. For this airing and cleaning a warm, sunny day should be selected and, whenever possible, on such days the cases should be opened; books, like people, are healthier when well supplied with good, fresh air.

< Book Rebinding Part 4