Dictionary.net

The act or process of refining gold or silver, etc., in a cupel.

The process of separating the silver or gold in alloys of lead and silver or of lead and gold.

The assaying of silver, etc., by melting it with lead in a cupel exposed to the air. The lead, being oxidized, dissolves the impurities, and all but the pure metal is absorbed by the cupel (q.v.).

n. The refining of gold, silver, and other metals, in a cupel.