It consisted of a basin or hearth, b, in which a fire of charcoal or coke was built, the fuel being carried above the level of the water-cooled tuyères, g g. On this mass of ignited fuel a charge of a ton or a ton and a half of pig iron was thrown, over which fuel was heaped, and the blast (which was regulated by the valves, k k) was then turned on. In about one hour and a half Fig. 21.—Cross-section of a Refinery. the pig iron was melted, and its upper surface as it lay in the hearth was exposed to the action of the blast (oftentimes in the larger refineries there were six tuyères, three on a side, but in some of the oldest refineries there was but one tuyère); this effected the oxidation and removal of considerable of the carbon, most of the silicon, and a portion of the sulphur, a large amount of "slag" being formed. About two hours after the commencement of the operation the metal was "tapped out" on to the "running-out bed," which was a shallow trough made of very thick castings; a section of which is shown at n. These castings were provided with flanges, which rested upon the sides, o o, of a box or channel, p, filled with water to cool the running-out bed, and promote the rapid solidification of the liquid refined iron; and as soon as this was accomplished the final cooling was hastened by a jet of water forcibly thrown upon the upper surface of the metal from a hose. This caused the "cinder" on this surface to separate in a great degree from the refined metal, which, when perfectly cool, was broken up into pieces of manageable size. The fracture of "refined metal" was white, inclined to