FURNACE

(Lat. fornax.) An apparatus wherein is placed a cavity to contain combustible matter, which in various ways is supplied with air to facilitate its combustion. The two cla es into which furnaces are divided are air or wind furnaces, and blast furnaces. In the former the air is conducted through the fire by the draught of a funnel or chimney which communicates with it; in the latter, the action of bellows or some other pneumatic apparatus supplies the air. The word furnace has generally, however, a more circumscribed application; being applied usually to an apparatus for the fusion of metals, or to that used in a chemical laboratory. [s. 494]