Editing Georgius Agricola (section)

== ''De re metallica'' ==
{{Main|De re metallica}}
[[Image:Georg Agricola-Titelblatt.jpg|thumb|left|''De re metallica'']]

Agricola's most famous work, the ''De re metallica libri xii'' was published the year after his death, in 1556; it was perhaps finished in 1550, since the dedication to the elector and his brother is dated to that year. The delay is thought to be due to the book's many woodcuts. The work is a systematic, illustrated treatise on [[mining]] and [[metallurgy#Extractive metallurgy|extractive metallurgy]]. It shows processes to extract [[ore]]s from the ground, and metals from ore.

Until that time, [[Pliny the Elder]]'s work ''[[Natural History (Pliny)|Historia Naturalis]]'' was the main source of information on metals and mining techniques. Agricola acknowledged his debt to ancient authors, such as Pliny and [[Theophrastus]], and made numerous references to Roman works. In [[geology]], Agricola described and illustrated how [[ore vein]]s occur in and on the ground. He described [[prospecting]] for ore veins and [[surveying]] in detail, as well as washing the ores to collect the heavier valuable minerals, such as [[gold]] and [[tin]]. The work shows [[water mill]]s used in [[mining]], such as the machine for lifting men and material into and out of a [[mine shaft]]. Water mills found application especially in crushing ores to release the fine particles of gold and other heavy minerals, as well as working giant [[bellows]] to force air into the confined spaces of underground workings.

Agricola described mining methods which are now obsolete, such as [[fire-setting]], which involved building fires against hard rock faces. The hot rock was quenched with water, and the [[thermal shock]] weakened it enough for easy removal. It was a dangerous method when used underground, and was made redundant by [[explosives]].

The work contains, in an appendix, the German equivalents for the technical terms used in the Latin text. Modern words that derive from the work include [[fluorspar]] (from which was later named [[fluorine]]) and [[bismuth]]. In another example, believing the black rock of the [[Schloßberg (Stolpen)|Schloßberg]] at [[Stolpen]] to be the same as Pliny the Elder's [[basalt]], Agricola applied this name to it, and thus originated a petrological term.

In 1912, the ''Mining Magazine'' (London) published an English translation of ''De re metallica''. The translation was made by [[Herbert Hoover]], the American mining engineer and his wife [[Lou Henry Hoover]]. Hoover was later [[President of the United States]].