Cruciate

( Bot.) Cro -shaped; cruciform. Crucible, n. [L. Lat. crucibulum; It. crogiuolo, and crocciulo, an earthen ve el for melting metals; Fr. creu set. See CROCK.] ( Chem.) A ve el made of some material capable of resisting a high temperature, used by chemists and metallurgists for fusing metals or chemical compounds. According to the material to be melted. and the heat required for fusion, they are made of platinum, iron, plumbago, porcelain, clay, or lime. Those made of hard refractory clay, such as the Cornish or He ian C., are most usually employed. They will stand a very high heat without melting Plumbago C. serve a double purpose, acting not only as ve els, but as reducing agents. Platinum C. are used in operations where a clay C. would be acted on by the fluxes employed. Where a very high temperature is required, as, for instance, in melting platinum, a lime C. is used. (Smelting.) A repository at the vent of a furnace for the fused metal.