Furnace
2 of the 7 encyclopedias on this shelf carry an entry for Furnace. Both are reproduced below, so you can see where they agree and where they differ.
Collier's New Encyclopedia (1921)
a place where a vehement fire and heat may be made and maintained, as for melting ores or metals, heating the boiler of a steam engine, of warming a house, baking pottery or bread, and other purposes. Furnaces are constructed in a great variety of ways, according to the different purposes to which they are applied. In constructing furnaces the following objects are kept in view: (1) To obtain the greatest quantity of heat from a given quantity of fuel. (2) To prevent the dissipation of the heat after it is produced. (3) To concentrate the heat and direct it as much as possible to the substances to be acted on. (4) To be able to regulate at pleasure the necessary degree of heat 's and have it wholly under the operator's management. An air furnace is one in which the flames are urged only by the natural draught; a blast furnace, one in which the heat is intensified by the injection of a strong current of air by artificial means; a reverberatory furnace, 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.
The Encyclopedia of Founding (1892)
A suitably provided chamber where fire is produced by the use of fuel, as for melting metals, smelting ores, etc., the former being a cupola, the latter a smelting furnace. When the fire receives no other support than a natural draught, it is termed a wind or air furnace; when a forcible current of air is injected by means of a fan, blower, or engine, it is a blast-furnace; and a reverberatory furnace when the flame in passing through towards the chimney is thrown down by a low arched roof upon the materials to be operated upon. See CUPOLA; REVERBERATORY FURNACE; BLAST-FURNACE; BRASS-FURNACE; also many other furnaces, in their respective order.