a volatile matter arising from wood and other fuel along with the smoke; or rather, it is the smoke itself condensed and gathered to the fides of the chim- ney. Though once volatile, however, foot cannot be again resolved into vapour; but, if distilled by a strong fire, yields a volatile alkali and empyreumatic oil, a considerable quantity of fixed matter remaining at the bot- tom of the distilling vessel. If burnt in an open fire, it flames with a thick smoke, whence other foot is pro- duced. It is used as a material for making sal ammoniac, and as a manure. See AMMONIA, muriate of; CHE- MISTRY Index.

SOOT Black. See COLOUR-Making.