Reverberatory Furnace: the Air Furnace for Melting Cast Iron (Bolland, 1893)

An air furnace melts iron apart from the fuel: coal burns on a grate at one end, and the flame is thrown down from a low arched roof onto the iron on the bed, then leaves by a tall chimney. The iron stays cleaner than in a cupola, so founders used it for guns, rolls, heavy scrap and lumps too big for the cupola. This furnace is 30 ft 6 in long and 7 ft wide outside, 5 ft wide inside, cased in bolted wrought-iron plates. Source: S. Bolland, The Iron Founder Supplement (1893), pp. 55-67. Unknown: brick sizes, plate thickness. Picture: Fig. 14 of the book.