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 sides of the chimney. Though once volatile, however, soot 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 bottom of the distilling vessel. If burnt in an open fire, it flames with a thick smoke, whence other soot is produced. It is used as a material for making sal ammoniac, and as a manure.