Georgius Agricola, Latin name of George Bauer (1494-1555), German mineralogist and metallurgist. His De Re Metallica (on the Nature of Metals) is a detailed record of 16th century mining procedures and the related sciences. The art of surveying is dealt with at length in Book V. Production of working plans for the owners, for estimating costs and ensuring there was no encroachment on other people's territory, depended on accurate measurement and calculations by the miners. Each method of surveying depended on the measurement of triangles. He describes the use of levelling instruments, plumetts and other instruments