author of the first comprehensive book on mining and metallurgy

Georg Bauer was born in Glauchau, in the province of Saxony, in what is now Germany, in 1494; it is not known when he took the latinized form of his name (agricola is the Latin and bauer the German for farmer). He studied the classics at Leipzig University, taught Latin and Greek for a few years, and then, in 1522, began to study medicine, first at Leipzig and then at Bologna and Padua in Italy. He took his medical degree in 1526, and began practicing medicine at Joachimsthal in 1527.

Joachimsthal was an important mining center of the time, especially for silver mining. Agricola spent a lot of time in the mines, hoping to find minerals that might be useful to medicine. In the process he became increasingly interested in the processes of mining and metallurgy, and the classification of rocks and ores. He may have also acquired a financial interest in some of the more profitable mines. Agricola must have also made a point of talking to the miners, because he became increasingly indignant on their behalf over the accidents they suffered because of the low standards of safety, and the illnesses and premature senility caused by their work. Like his contemporary, Paracelsus, Agricola knew that these were "industrial diseases," even though that term had not yet been coined. He wrote a detailed description of the skin lesions with which salt miners were often inflicted.

Agricola rejected magical and philosophical links to science, basing his work on direct observation and field study instead. With the encouragement of another contemporary, Erasmus, he wrote a series of books and treatises on several aspects of mining and mineral ores. The first of these, De Orta et Causis Subterraneorum, was published in 1546. Considered the first book on physical geology, it is notable for its descriptions of wind and water as powerful geological forces, and for its explanation of earthquakes and volcanic eruptions as produced by subterranean vapors and gases heated by the Earth's internal heat. De Natura Fossilium (On the Nature of Fossils), also published in 1546, has been described as the first textbook on mineralogy (at that time the word fossil applied to any object dug up from the ground). In this book Agricola described the role of erosion in forming the shapes of mountains and correctly theorized that veins of mineral ore in rocks had an origin in silt deposits. He also worked out a classification of crystals based on their geometric shapes and advocated the use of magnetic needles in surveying for metal ores. Although De Natura Fossilium contained no illustrations of any kind, most of his description of fossils are instantly recognizable. And, while Agricola rejected some of the popular superstitions of his time, he listed the medicinal and even magical uses to which rocks, minerals and fossils were put: powdered lapis judaicus was prescribed for kidney stones, while ostreites (fossil oyster shell), moistened with water, was used to reduce inflammation of the breasts, heal ulcers, and kill crawling insects.

Even though Agricola was a Catholic, the Protestant Duke of Saxony appointed him to be Burgomaster (mayor) of Chemnitz, another major center of the mining industry, in 1546. Agricola continued both his medical practice and his geological studies there.

All of Agricola's lifelong scholarship culminated in the production of what would become his greatest (and last) work, De Re Metallica (On Metals), even though the book would not be published until a year after his death. Richly illustrated with superb woodcuts by Hans Manuel, the book was quickly recognized as a text of high scientific stature. It went through many editions, and remained the standard text for 200 years. De Re Metallica is a comprehensive treatise on every aspect of metallurgy and mining. It summarizes all that was known on the subject from classical times onward and describs the techniques of mine engineering and surveying as well as of ore processing. It even covers the law of land ownership insofar as this bears on mining, the patterns of employment and labor management, and the economics involved. In writing the book, Agricola established mineralogy as a scientific discipline.

Georgius Agricola died on November 21, 1555.

An illustration of the smelting of ores. (A) and (B) are furnaces into which the ores are fed and in which they are smelted. The molten metal runs out of the tapholes (C) into the forehearths (D) and is extracted at the forehearths' tapholes (E). (F) is the dipping pot. A smelter (G) is carrying a wicker basket of charcoal to the furnace. The other smelter is breaking up the slag which has solidified at the taphole of the furnace with a hooked bar (H). The molten metal is then poured into molds. (I) is a heap of charcoal, quantities of which are measured up in a wicker box on the barrow (K). This type of furnace system was very efficient in that it could smelt large quantities of metal for continuous periods of up to three days. Copper, lead, silver, and gold could be extracted from very poor ores without the use of expensive fluxes, and the extraction rate was very high.

Composite picture of three types of bellows used to ventilate mine shafts. A-F: bellows operated by workman. G-M: a horse trod on the steps covering a wooden wheel; cams attached to the axle compressed the bellows. N-R: two-wheeled system with a horse driving an upright wheel which in turn drove a horizontal one attached to the bellows.

[both illustrations are from De Re Metallica]

SOURCE
Anthony Feldman and Peter Ford Scientists and Inventors, The People Who Made Technology from Earliest Times to Present Day New York: Facts on File, 1979

SEE ALSO
Paracelsus

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This page was last updated on November 21, 2017.