A classification of safes embraces, _Fire-proof_, _Burglar-proof_, _Safe Bolt Works_, _Express and Deposit Safes and Boxes_, _Circular Doors_, _Pressure Mechanism_, and _Water and Air Protective Devices_. The attention of the earliest inventors of the century were directed toward making safes fire-proof. In England the first patent granted for a fire-proof safe was to Richard Scott in 1801. It had two casings, an inner and outer one, including the door, and the interspace was filled in with charcoal, or wood, and treated with a solution of alkaline salt. This idea of interspacing filled in with non-combustible material has been generally followed ever since. The particular inventions in that line consist in the discovery and appliance of new lining materials, variations in the form of the interspacing, and new methods in the construction of the casings, and the selection of the best metals for such construction. In 1834 William Marr of England patented a lining for a double metallic chest, filled with non-combustible materials such as mica, or talc clay, lime, and graphite. Asbestos commenced to be used about the same time. The great fire in New York City in 1835, destroying hundreds of millions of dollars’ worth of property of every description, gave a great impetus to the invention of fire-proof safes in America. B. G. Wilder there patented in 1843 his celebrated safe, now extensively used throughout the world. It consisted of a double box of wrought-iron plates strengthened at the edges with bar iron, with a bar across the middle; and as a filling for the interspaces he used hydrated gypsum, hydraulic cement, plaster of paris, steatite, alum, and the dried residuum of soda water. Herring was another American who invented celebrated safes, made with a boiler-iron exterior, a hardened steel inner safe, with the interior filled with a casting of franklinite around rods of soft steel. Thus the earth, air and water were ransacked for lining materials, in some cases more for the purpose of obtaining a patent than to accomplish any real advance in the art. Water itself was introduced as a lining, made to flow through the safes, sometimes from the city mains, and so retained that when the temperature in case of fire reached 212° F. it became steam; and an arrangement for introducing steam in place of water was contrived. Among other lining materials found suitable were soapstone, alumina, ammonia, copperas, starch, Epsom salts, and gypsum, paper, pulp, and alum, and a mixture of various other materials. After safes were produced that would come out of fiery furnaces where they had been buried for days without even the smell of fire or smoke upon their contents, inventors commenced to direct their attention to burglar-proof safes.