FIRE-PROOF SAFES AND REPOSITORIES are used as receptacles for deeds, paper money, account books, and other valuables. They are now regular articles of com merce, and are to be found in almost every counting-house, lawyer's office, jeweler's or watchmaker's shop or warehouse, and are indispensable to banking and such-like establishments. Our forefathers used oaken chests secured with iron straps and studs for similar purposes. That which formerly contained the crown jewels of Scotland, and is still exhibited in Edinburgh castle, is a good example. Subsequently, iron chests made simply of stout cast or wrought iron were used. The modern safe has double walls and doors of stout iron plates, and the space between the plates is filled with some substance that shall resist the transmission of the heat, which would be readily conducted through solid iron. The materials used for these linings are very various—sand, dried clay, charcoal, ashes, bone-dust, alum, gypsum, etc. The safes of Messrs. S. Mordan & Co., which are largely used by bankers, are lined with a mix ture of equal parts of sawdust and alum. Some makers include small vessels con taining liquids; the vessels burst when heated, and the liquids exert some cooling effect. Alum acts in nearly the same manner. It contains 24 equivalents of water, or nearly half its weight. At 212°, ten equivalents are driven off in vapor; at 248°, ten more; and at 392°, the four remaining equivalents are volatilized. It is a mis
take, however, to suppose that any of these linings can render such a safe really fireproof; and this is admitted by the more scrupulous manufacturers, who carefully abstain from using the designation of "fire-proof," but apply that of "fire-resisting," which honestly describes all that they are capable of doing, as they may resist the action of fire for a considerable time; but whether or not their contents may be ulti mately preserved from a fire, is simply a question of the duration and intensity of the heat to which they are exposed. Their great weight in some cases assists in preserving them, especially when on an upper floor, as such a safe would be the first thing to break through the burning joists and descend to the lower part of the build ing, where the fire is usually the most smothered. These safes are sometimes let into recesses of stout masonry, built on purpose, and protected by an additional double iron door. This, of course, adds greatly to their security. All such safes should of course be secured by the best locks that can be made, protected by every possible precaution against picking, blowing up by gunpowder, or other violence. See Locx, and SAFES, FIRE-PROOF.