A term generally applied to the residue of combustion; generally limited to vegetable ashes, though sometimes applied to mineral calces. Vegetable ashes differ according to the degree of heat to which they have been exposed. With a moderate heat they contain much charcoal; but with a stronger, a white light earth, with some alkaline salts,"and perhaps a little oil, only remain. In this state we find them in commerce, under the name of potashes, pearlashes, etc.
In these ashes the minuter modern chemistry will discover a small portion of magnesia, a little iron, and perhaps some phosphoric salts, with a small quantity of lime; but these have little reference to medicine. They must all be separated before the ashes can be employed as a remedy.
Ashes, animal. These are more refractory than the vegetable ashes,, as containing a larger portion of phosphoric salts, but the only substance of this kind used in medicine is the cornu cervi calcinatum, which owes all its virtue to a little remaining mucilage. The lixiviated salts of bones are used in chemistry to form cupels for assaying metals, as they resist vitrification from the calces of lead.