Agricola, Georgius (1494-1555)

German physician and geologist

Georgius Agricola was born Georg Bauer, but later Latinized his name to Georgius Agricola, as was the custom of the time. (The German word bauer and the Latin word agricola both mean farmer.) His research and publications on a wide range of geologic topics, including mineralogy , paleontology, stratigraphy , mountains, earthquakes, volcanoes, and fossils have led some biographers to describe him as the forefather of geology or one or more of its many branches.

After earning a medical degree in Italy, Agricola was appointed physician in the town of Joachimstahl in Bohemia (now Jachymov, Czechoslovakia). It was in this important mining center that he began some of his earliest research into mining and a lifelong love of geologic studies. When he later relocated to the mining center of Chemnitz (now in modern day Germany) he continued a remarkably systematic and meticulous research into the many facets of mining.

One of his earliest works, published in 1546, was De Natura Fossileum (On the nature of fossils). In this book, he summarized much of what was known by the ancient Greeks and Romans about fossils, minerals , and gemstones . In Agricola's time the meaning of the word fossil encompassed all three of these terms. It wasn't until early in the nineteenth century that the word was given its modern meaning. However, unlike other sixteenth century researchers, he did not accept ancient wisdom as fact. He ridiculed the mystical properties that many ancient scientists, physicians, and philosophers had assigned to fossils, minerals, and gemstones and derided Greek and Roman methods of classification. Instead of using alphabetical listings or groupings by supposed magical traits, Agricola developed a system that that relied on such properties as odor, taste, color, combustibility, shape, origin, brittleness, and cleavage. This classification system has endured for more than 450 years.

In another book, De Ortu et Causis Subterraneum (Of subterranean origins and sources), published the same year as De Naturea Fossileum, Agricola attempted to explain the existence of mountains, volcanoes, and earthquakes. Although the scientific equipment and knowledge of his time made some explanations impossible, Agricola recognized the power of wind and water as an erosive force, and associated the hot interior of Earth with volcanoes and earthquakes.

Despite the remarkable observations made by Agricola in De Natura Fossileum, De Ortu et Causis Subteraneum, and at least four other books, it is his seventh and final book, De Re Metallica (On the subject of metals ), published in 1556 (one year after his death) that many geologists consider to be his finest work.

De Re Metallica was the culmination of years of careful and patient research in the two mining towns where Agricola served as a physician. Unlike many scientists before and during his time, he did not rely on hearsay or the work of others. According to Agricola, everything he wrote about he observed first hand or learned from reliable sources.

De Re Metallica was handsomely printed and illustrated with over 250 woodcuts on assaying (analyzing ores for their metallic content), pumps for removing water from mines, machinery for digging, and processes for smelting. The text included such topics as stratigraphy, minerals, finding and identifying ores, administrating mining operations, surveying, and even diseases related to mining.

Given the remarkable depth and scope of Georgius Agricola's research and publications it is not surprising that many modern geologists and historians consider his contributions essential to the early development of the science of geology.