Henckel, Johann Friedrich

(b. Merseburg, Germany, 1 August 1678; d. Freiberg, Saxony, Germany, 26 January 1744)

chemistry, mineralogy.

The second son of Merseburg’s town physician, Henckel was apparently intended for the clergy, having enrolled at the University of Jena to study theology in 1698. But he soon switched to medicine, probably to pursue his childhood interest in “the book of nature.” During his medical studies he most likely attended chemistry lectures by G. W. Wedel. After a few years at Jena, Henckel proceeded to Dresden, where he first worked under the supervision of a physician engaged in chemical research and then opened his own practice. In 1711 he resumed his medical studies at the University of Halle, taking an M.D. that year under the chemist G. E. Stahl Henckel subsequently settled in the important Saxon mining town of Freiberg, where he practiced medicine for the next eighteen years, becoming district physician in 1718 and town physician and mine physician in 1721.

In Freiberg Henckel his leisure time to give private courses to “lovers of chemistry” and to carry out experiments. He soon became quite proficient in using heat and fire for the chemical analysis of mineral substances. In the 1720’s he quickly attracted the acclaim of the German scientific world with the publication of his first major works: Flora saturnizans (Leipzig, 1722), an inquiry into the relations and similarities between plants and minerals; Pyritologia (Leipzig, 1725). an encyclopedic study of the pyrites; and De mediorum chymicorum (Dresden-Leipzig, 1727) an investigation of mediated reactions. Besides regaling his readers with a host of novel experiments and observations, Henckel championed limited empirical research, Stahlian chemistry, and natural religion.

Patronized by an influential noble, Henckel resigned his posts in Freiberg and went to Dresden in 1730. Two years later he used the leverage of a foreign call (possibly from the St. Petersburg Academy) to have himself appointed councilor of mines with a handsome salary and a substantial budget for investigating Saxony’s mineral resources. He soon returned to Freiberg and, with state help, established a large laboratory in which he not only discharged his official duties but also carried out his published research and resumed his annual course in metallurgical chemistry. This course, which was only open to six students at a time, soon achieved renown throughout Germany and Eastern Europe for its profundity and utility. Consequently, when Henckel died in 1744, some of his disciples hoped that the course would be continued under a new teacher or, better yet, that a mining academy would be founded. Although nothing was done at the time, these hopes were eventually realized: in 1753 the Saxon government charged C. E. Gellert with teaching chemistry in Freiberg, and in 1765 it created the famous Bergakademie there.

Henckel’s influence also extended to the rapidly developing science of chemistry. His exacting course did much to shape the perceptions and techniques of two significant pupils, A. S. Marggraf and M. Lomonosov. His work on pyrites and other minerals exerted a strong influence on J. H. Pott, J. G. Lehmann, and others engaged in mineral analysis. Finally, his publications, which appeared in new German editions and in English and, especially, French translations in the two decades following his death, played an important role in the spread of the Stahlian approach to chemical phenomena.

BIBLIOGRAPHY

A fairly complete bibliography of Henckel’s works appears in J. R. Partington, A History of Chemistry, II (London. 1961). 706–707. In addition to Partington, who incorrectly gives Henckel’s date of birth as 11 Aug. 1679. see Walther Herrmann, “Bergrat Henckel. Ein Wegbereiter der Bergakademie,” in Freiberger Forschungshefte: Kultur und Technik, 37D (1962); and Neue deutsche Biographie, VIII (Berlin, 1969), 515–516.

Karl Hufbauer