Laboratory for refining gold and silver, showing typical laboratory equipment. 1, Athanor or 'Slow Harry', a self-feeding furnace maintaining a constant temperature. 2,2. Side furnaces with receivers on stools, 4,4. On right of top shelf is a glass vessel shaped like an Hermetic vase. From 1683 English edition of Beschreibung allerfurnemisten mineralischen Ertzt, Lazarus Ercker, (Prague, 1574). Copperplate engraving.