XCUPEL, n. A small cup or vessel used in refining metals. It retains them while in a metallic state, but when changed by fire into a fluid scoria, it absorbs them. Thus when a mixture of lead with gold or silver is heated in a strong fire, the lead is oxydated and vitrified, and sinks into the substance of the cupel, while the gold or silver remains pure. This kind of vessel is made usually of phosphate of lim, or the residue of burnt bones, rammed into a mold, which gives it its figure.