Separating silver from gold, 1580.
GERMANY - JUNE 10: Woodcut illustration from 'Beschreibung aller furnemisten mineralischen Ertzt vnnd Bergtwercks arten' ('Description of the Principle Mineral Ores and Methods of Mining') by Lazarus Ercker (d 1594) published in Frankfurt-am-Main in 1580. In 1554 Ercker was appointed assayer at Dresden and later became a control tester of coins. This book is a mine of information concerning sixteenth century metallurgy and assaying. It can be regarded as the first manual of analytical and metallurgical chemistry. (Photo by SSPL/Getty Images)