Furnace
a place where a vehement fire and heat may be made and maintained, as for melting ores or metals, of a steam engine, heating the boiler of a steam engine, bread, and other purposes. Furnaces are constructed in a great variety of ways, according to the different purposes to furnaces the following objects are kept in view: (1) To obtain the greatest 's quantity of heat from a given quantity of fuel. (2) To prevent the dissipation of the heat after it is produced. (3) quantity of heat from a given quantity much as possible to the substances to be of fuel. (2) To prevent the dissipation pleasure the necessary degree of heat and have it wholly under the operator's management. An air furnace is one in which the flames are urged only by the acted on. (4) To be able to regulate at pleasure the necessary degree of heat and have it wholly under the operator's which the heat is intensified by the inmanagement. An air furnace is one in which the flames are urged only by the natural draught; a blast furnace, one in nace, one in which the flames in passing to the chimney are thrown down by a low-arched roof on the objects which it is intended to expose to their action. See BLAST FURNACE.