ÆS, properly signifies copper, or money coined of that metal. See COPPER.
Æs flavum, yellow copper, among the Romans, an appellation given to the coarser kinds of brass. See BRASS.
Æs calcarium, the name of a certain regulus of antimony, employed in preparing the fine blue colour called smalt.
Æs ustum, a preparation of copper, by exposing plates of it in a reverberatory furnace, till they crumble into a powder, which is called æs ustum. It is used for colouring glass, eating off dead flesh, or cleansing foul ulcers.