Injurious Influences to which Books are Subjected
Gas Fumes.—The investigation of the Society of Arts Committee shows that—
“Of all the influences to which books are exposed in libraries, gas fumes—no doubt because of the sulphuric and sulphurous acid which they contain—are shown to be the most injurious.”
The injurious effects of gas fumes on leather have been recognised for a long time, and gas is being, very generally, given up in libraries in consequence. If books must be kept where gas is used, they should not be put high up in the room, and great attention should be paid to ventilation. It is far better, where possible, to avoid the use of gas at all in libraries.
Light.—The committee also report that “light, and especially direct sunlight and hot air, are shown to possess deleterious influences which had scarcely been suspected previously, and the importance of moderate temperature and thorough ventilation of libraries cannot be too much insisted on.”
The action of light on leather has a disintegrating effect, very plainly seen when books have stood for long periods on shelves placed at right angles to windows. At Oxford and Cambridge and at the British Museum Library the same thing was noticed. The leather on that side, of the backs of books, next to the light, was absolutely rotten, crumbling to dust at the slightest friction, while at the side away from the light it was comparatively sound. Vellum bindings were even more affected than those of leather.
The committee advise that library windows exposed to the direct sunlight should be glazed with tinted glass.
“Some attempts have been made to determine the effect of light transmitted through glasses of different colours, and they point to the fact that blue and violet glass pass light of nearly as deleterious quality as white glass; while leathers under red, green, and yellow glasses were almost completely protected. There can be no doubt that the use of pale yellow or olive-green glass in library windows exposed to direct sunlight is desirable. A large number of experiments have been made on the tinted ‘cathedral’ glasses of Messrs. Pilkington Bros., Limited, with the result that Nos. 812 and 712 afforded almost complete protection during two months’ exposure to sunlight, while Nos. 704 and 804 may be recommended where only very pale shades are permissible. The glasses employed were subjected to careful spectroscopic examination, and to colour-measurement by the tintometer, but neither were found to give precise indications as to the protective power of the glasses, which is no doubt due to the absorption of the violet, and especially of the invisible ultra-violet rays. An easy method of comparing glasses is to expose under them to sunlight the ordinary sensitised albumenised photographic paper. Those glasses under which this is least darkened are also most protective to leather.”
Tobacco.—Smoking was found to be injurious, and it is certainly a mistake to allow it in libraries.
“The effect of ammonia vapour, and tobacco fumes, of which ammonia is one of the active ingredients, was also examined. The effect of ammonia fumes was very marked, darkening every description of leather, and it is known that in extreme cases it causes a rapid form of decay. Tobacco smoke had a very similar darkening and deleterious effect (least marked in the case of sumach tanned leathers), and there can be no doubt that the deterioration of bindings in a library where smoking was permitted and the rooms much used, must have been partly due to this cause.”