Soap-kettle
Some of the kettles for this purpose are covered in and provided with a large bend-pipe to receive the vapors. The watery matter is condensed, and drawn off at the bottom; the inflammable vapors are drawn under the fire. See PANS.
Soapstone is steatite, and termed soapstone because of the smooth, greasy feel it has between the fingers. It is a hydrated silicate of magnesia--a massive variety of talc, which when pure and compact is highly refractory, and suitable for furnace-linings and for the manufacture of fire-brick. Soapstone, ground very fine and mixed with carbon facings, makes an excellent material for coating the moulds of hollow ware and stove-plate castings, being especially useful as a return-facing for printing with. See RETURN-FACING; PRINTING.