Crucible Furnace: the Brass Founder's Sunk Coke Air Furnace (Larkin, 1907)

The brass founder's crucible furnace: a firebrick-lined pit sunk below the floor, fired with hard coke on an iron grating over the ash-pit, closed by a dome-shaped iron cover and drawn by a flue with a damper. The crucible sits on a firebrick in the middle of the fire, lidded, with coke banked round it, until the metal is melted. Result: a coke-fired crucible furnace for melting brass and bronze. Source: J. Larkin, The Practical Brass and Iron Founder's Guide (1907), pp. 96-99. Unknown: all sizes. Picture drawn by Youblob.