A third enemy of the book is heat. Most libraries are unfortunately over-heated,-sometimes from defective means of controlling the temperature, and sometimes from carelessness or want of thought in the attendant. A high temperature is very destructive to books. It warps their covers, so that volumes unprotected by their fellows, or by a book support, tend to curl up, and stay warped until they become a nuisance. It also injures the paper of the volumes by over-heating, and weakening the tenacity of the leaves held together by the glue on the back, besides drying to an extreme the leather, till it cracks or crumbles under the heat. The upper shelves or galleries of any library are most seriously affected by over-heating, because the natural law causes the heat to rise toward the ceiling. If you put your hand on some books occupying the highest places in some library rooms, in mid-winter, when the fires are kept at their maximum, the heat of the volume will almost burn your fingers. If these books were sentient beings, and could speak, would they not say-"our sufferings are intolerable?"
The remedy is of course a preventive one; never to suffer the library to become over-heated, and to have proper ventilation on every floor, communicating with the air outside. Seventy degrees Fahrenheit is a safe and proper maximum temperature for books and librarian.
The mischief arising from gas exhalations is another serious source of danger to books. In many well-lighted libraries, the heat itself from the numerous gas-burners is sufficient to injure them, and there is besides a sulphuric acid escaping from the coal-gas fluid, in combustion, which is most deleterious to bindings. The only remedy appears to be, where libraries are open evenings, to furnish them with electric lights. This improved mode of illumination is now so perfected, and so widely diffused, that it may be reckoned a positive boon to public libraries, in saving their books from one of their worst and most destructive enemies.
Another of the potent enemies of books is fire. I refer, not to over-heating the rooms they occupy, but to the risk they continually run, in most libraries, of total destruction. The chronicle of burned libraries would make a long and melancholy record, on which there is no space here to enter. Irreparable losses of manuscripts and early printed books, and precious volumes printed in small editions, have arisen from men's neglect of building our book-repositories fire-proof. In all libraries not provided with iron or steel shelves, there is perpetual danger. Books do not burn easily, unless surrounded with combustibles, but these are furnished in nearly all libraries, by surrounding the books on three sides with wooden shelves, which need only to be ignited at any point to put the whole collection in a blaze. Then follows the usual abortive endeavor to save the library by the aid of fire engines, which flood the building, until the water spoils nearly all which the fire does not consume. The incalculable losses which the cause of learning has sustained from the burning of public, university and ecclesiastical libraries are far greater than the cost which the provision of fire-proof repositories would have entailed.
Of late years, there has been a partial reform in library construction. Some have been built fire-proof throughout, with only stone, brick, concrete and iron material, even to the floors and window casings. Many more have had iron shelves and iron stacks to hold the shelves constructed, and there are now several competing manufacturers of these invaluable safeguards to books. The first library interior constructed wholly of iron was that of the Library of Congress at Washington, which had been twice consumed, first when the Capitol was burned by the British army in 1814, and again in 1851, through a defective flue, when only 20,000 volumes were saved from the flames, out of a total of 55,000. The example of iron construction has been slowly followed, until now the large cities have most of their newly-constructed libraries approximately fire-proof, although many are exposed to fire in parts, owing to a niggardly and false economy. The lesson that what is worth doing at all is worth doing well, and that every neglect of security brings sooner or later irreparable loss, is very slowly learned. Whole hecatombs of books have been sacrificed to the spirit of commercial greed, blind or short-sighted enough not to see that secure protection to public property, though costlier at first, is far cheaper in the end. You may speak of insurance against library losses by fire, but what insurance could restore the rare and costly Shakespearean treasures of the Birmingham Free Library, or the unique and priceless manuscripts that went up in flames in the city library of Strasburg, in 1870, or the many precious and irreplaceable manuscript archives of so many of our States, burned in the conflagration of their capitols?
One would think that the civilized world had had lessons enough, ever since that seventh century burning of the Alexandrian library by the Caliph Omar, with that famous but apocryphal rhetorical dilemma, put in his mouth perhaps by some nimble-witted reporter:-"If these books agree with the Koran, they are useless, and should be burned: if not, they are pernicious, and must not be spared." But the heedless world goes carelessly on, deaf to the voice of reason, and the lessons of history, amid the holocausts of literature and the wreck of blazing libraries, uttering loud newspaper wails at each new instance of destruction, forgotten in a week, then cheerfully renewing the business of building libraries that invite the flames.