On October 22, 1659, German chemist, physician and philosopher Georg Ernst Stahl was born. Stahl developed the phlogiston theory of combustion and of such related biological processes as respiration, fermentation, and decay. Combustible objects, he said, were rich in phlogiston, and during combustion is lost. The remaining ash, now having no phlogiston, could no longer burn. Until the late 18th century his works on phlogiston were accepted as an explanation for chemical processes.
Georg Ernst Stahl was born in St. John’s Parish in Ansbach, Brandenburg in 1659 and was raised in Pietism. His interests in chemistry were due to the influence a professor of medicine, Jacob Barner, and a chemist, Johann Kunckel von Löwenstjern. In the late 1670s, Stahl began to study medicine at the University of Jena. Stahl’s success at Jena earned him a M.D. around 1683 and then he went on to teach at the same university. Through teaching at the university, Stahl gained a good reputation and was hired as the personal physician to Duke Johann Ernst of Sachsen-Weimar. He joined the faculty of the University of Halle in 1694 and became the physician and counselor to King Friedrich Wilhelm I of Prussia and in charge of Berlin’s Medical Board.
The probably best known works by Georg Stahl were accomplished during the time he worked at Halle University. He believed that chemistry could not be reduced to mechanistic views entirely. Stahl did probably not believe that atomic theories were enough to describe the chemical processes that go on. He believed that atoms could not be isolated individually and that they join together to form elements. He took an empirical approach when establishing his descriptions of chemistry. Stahl used the works of Johann Joachim Becher to help him come up with explanations of chemical phenomena. The main theory that Stahl got from J. J. Becher was the theory of phlogiston. This theory did not have any experimental basis before Stahl. He was able to make the theory applicable to chemistry. This theory was later replaced by Antoine-Laurent Lavoisier’s theory of oxidation. He also propounded a view of fermentation which in some respects resembles that supported by Justus von Liebig a century and half later. Although his theory was replaced, Stahl’s theory of phlogiston is seen to be the transition between alchemy and chemistry.
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