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"The section and ground plan of one of the older forms of open-mouthed furnaces used at Dowlais (Truran), consisting of a heavy mass of mascury, square at base, strongly braced together with iron tie-rods, rising in the shape of a truncated pyramid to the height of the boshes, and then surmounted with a conical top surrounded at the throat by a gallery for the introduction of the enarging materials. In the square base were four arched recesses or tuyere houses, one on each side, F, F, for the introduction of G also serving for the removal of cinder and the tapping of the furnace for the running of the pig. The lowest portion of the hearth or crucible, A, was constructed of refractory sandstone, grit, or conglomerate, or of difficulty fusible firebrick, the inner portion of the upper part of the furnace being also built of firebrick set in fireclay with an air course between the double lining thus constructed; exteriorly the furnace was built of less expensive and refractory materials, usually of stone, strongly bound round with iron hoops." — The Encyclopedia Britannica, 1893

Furnace

"The section and ground plan of one of the older forms of open-mouthed furnaces used at Dowlais (Truran),…

"The more modern furnaces are constructed like this, but the masonry at the base is still less massive, so that, instead of there being four distinct tuyere houses, the separating walls of the houses are wholly cut away and replaced by a number of stout iron pillars on which rests the greater portion of the weight of the superstructure; through the walls of the hearth are pierced conical arched openings for the tuyeres; the throat is fitted with a valve for introducing materials from time to time, such as the cup and cone arrangement." — The Encyclopedia Britannica, 1893

Furnace

"The more modern furnaces are constructed like this, but the masonry at the base is still less massive,…