Safe, a strong box or closet for the preservation of money, valuable papers, etc., usually made of iron, and as nearly proof against fire and burglars as possible. Until the present century the most usual safes were boxes of oak or other hard wood, strengthened by iron bands and provided with several locks. The first English patent for a fire-resisting safe was to Richard Scott in 1801. It consisted of an inner and an outer casing of metal, the space between being filled with charcoal or wood treated with an alkaline salt. The first American safes that attained any celebrity were those constructed under the patent of C. J. Gayler, issued in 1833. They were double chests with spaces between them for air, or other good non-conductors of heat. The great fire in New York of 1835 gave rise to several new inventions for increasing the fire-proof quality of safes. That patented by Mr. B. G. Wilder of New York obtained the precedence, and the safes made on this plan are still in extensive use in this country and in Europe. They consist of a double box of wrought-iron plates strengthened at the edges with bar iron, and in the larger sizes with a bar across the middle. The space between the outer and inner plates is filled with the patented composition of plaster of Paris and mica.

The use of asbestus with plaster of Paris has also been patented. The latter answers a very good purpose used alone, and other good incombustible non-conductors also employed for filling are clay, hydraulic cement, and a mixture of alum, fire clay, and carbonate of lime or chalk. An excellent filling is a mixture of alum and plaster of Paris. Within a few years great ingenuity has been employed in the construction of safes and locks, and it has become an important industry in the United States. Safes are now made to defy opening by any manipulation (see Lock), and there are devices which make it difficult or impossible for a burglar to introduce gunpowder without consuming a long time in boring. A contrivance to prevent boring has been patented by Mr. Henry Geering of Birmingham, England, which consists in placing in front and on each side of the lock a set of movable cylindrical steel bars, so that when the burglar's drill has penetrated through the outer plate it cannot get a bearing upon the rotating bars.