1-152-542 - Ann Ronan Picture Library/Heritage-Images

Crushing gold bearing ores in mills similar in principle to flour mills, 1556. At bottom left goats in a treadmill produce horizontal power which is transferred to a mill (A) through a crown-and-pinion. At bottom right men turn a capstan and power is transferred through a tooth-and-pinion. From De re metallica by Georgius Agricola. (Basel, 1556).