Lehmann, Johann Gottlob
Lehmann, Johann Gottlob
(b. Langenhennersdorf, near Pirna, Germany, 4 August 1719d. St. Petersburg, Russia [now Leningrad, U.S.S.R.], 22 January 1767)
medicine, chemistry, metallurgy, mineralogy, geology.
Lehmann was the son of Martin Gottlob Lehmann, a prosperous gentleman farmer, and Johanna Theodora Schneider. His early education was largely at the hands of private tutors, although he did attend the Fürstenchule, in Schulpforta, for one semester in 1735 before ill health forced him to withdraw. In 1738 he matriculated as a medical student at the University of Leipzig; the following year he transferred to the University of Wittenberg, where he studied with the anatomist Abraham Vater. He received the M.D. in 1741, with a dissertation on the nervous papillae.
Lehmann then went to Dresden to practice medicine, but soon, having become acquainted with the natural scientists resident there, discovered his real field of interest to be mining and metallurgy. Saxony, a mining center, was an ideal place to take up that subject, and Lehmann became encouraged in all aspects of it. He was particularly concerned with the origins and distribution of ore deposits and with the chemical composition of various ores. He made field trips, among them one to Bohemia, to further his Knowledge, and by 1750, the year in which he left Dresden for Berlin, he had become known for his writings on mines and mining.
Christlob Mylius, a scientist and a friend of Lehmann’s, wrote that Lehmann initially came to Berlin in connection with the establishment of the state porcelain factory there. If such were the case, he did not participate in this enterprise for long, since shortly after his arrival he received an official commission to study mining procedures in the Prussian provinces and to make recommendations for their improvement. He spent several years on this project, mostly in the Harz. In August 1754 Lehmann was appointed Bergrat; he served as director of copper mining and of the Bureau of Mines in Hasserode, where he also established a smelter and factory for manufacturing blue pigment from cobalt from a neighboring mine. In 1755 and 1756 Lehmann traveled in Silesia in his official capacity.
In 1756, too, Lehmann settled in Berlin, having married Maria Rosina von Grünroth. He had been a member of the Royal Prussian Academy of Sciences since 1754, and his work in the capital was done largely under the auspices of that body. Lehmann thus entered into a period of extraordinary scientific activity, publishing his researches in chemistry, geology, and mineralogy. Of these, the most important and lasting were his geological studies. In geology Lehmann emphasized the importance of geological strata in determining the history of the earth; he was also one of the first to seek physico-chemical explanations for the origin of mineral deposits within the context of that history. (His new notion of the composition of the earth further enabled him to reach a theory of the propagation of earthquakes as being dependent on the “inner structure of the surface of the earth.” )
In his Versuch einer Geschichte von Flötz-Gebürgen of 1756, Lehmann, in discussing sedimentary rocks, described and compared sequences of strata on the basis of his own novel observations. Recognizing that the older strata were formed by the action of water, he developed the laws governing the formation of mountains, making a distinction between what he called “Ganggebürge”—a mountain formed of veined rock—and “Flötzgebürgen,” mountains formed of stratified rock. These are now called Unterbau and Oberbau (substructure and superstructure), respectively. Drawing upon his observations, Lehmann was to draw up the first geological profile. In it he demonstrated that rocks do not lie next to each other in a haphazard way, but rather are formed in historical sequence. He thus may be considered the founder of stratigraphy; his attempt to establish the laws underlying the formation of the earth provided the basis for modern geology.
Lehmann’s work in chemistry-which, indeed, constituted the greatest part of his researches-is today primarily of historical value. In his studies of rocks and ores he sought to determine their composition and metallurgical properties, and he suggested a system of classification based upon chemical composition (in contrast to Agricola’s classification by external characteristics and Linnaeus’ classification by crystal form). He analyzed many minerals for the first time; these analyses led to the discovery of new metals, including cobalt and tungsten. Lehmann’s Cadmiologia of 1760 dealt specifically with cobalt ores, treating their occurrence, mineralogy, and chemistry, and the technology necessary to their mining and Commercial. But because he was mining and commercial use limited to the techniques of quantitative analysis, Lehmann was able to make no fundamental and lasting contribution to the development of chemistry.
Mining technology was the framework into which Lehmann fitted all his research. He consciously sought to introduce into mining new scientific findings from all the natural sciences to enrich the technology that had evolved over the centuries. An uncompromising empiricist, Lehmann brought this point of view to his work in the field, in the mine, and in the laboratory. Following in the steps of Karl Friedrich Zimmermann, Lehmann advocated the establishment of specialized research institutions; he envisioned a technical teaching and research institute that would be the equal in prestige of the established universities. He was rewarded in his efforts by the founding of the Freiberg Bergakademie in 1765.
In 1760 Lehmann was invited to St. Petersburg by the Imperial Academy of Sciences. He accepted the following year, and in July 1761 left Berlin for Russia, where he took up a post as professor of chemistry at the University of St. Petersburg and director of the Academy’s natural history collection. He also continued his researches and, in the five and one-half years that remained to him, made thirty-seven reports to the Academy on the composition of minerals, the smelting of ores, the composition of soils and peats, the commercial manufacture of alum, fossil remains, and the geological structure of both specific regions and of the whole earth. He proposed the establishment of a governmental department to supervise the exploration of Russia’s mineral resources through a cartographical survey of geological relationships. (In this Lehmann was ahead of his time; two years after his death Catherine the Great commissioned the first of several Siberian explorations, giving Pallas the particular charge of conducting geological and orographic observations.) Lehmann’s death, at fortyseven, was caused by a bilious fever, and not by arsenic poisoning, as rumored.
I. Original Works. Bruno von Freyberg gives a list of 112 titles in Johann Gottlob Lehmann, ein Arzt, Chemiker, Metallurg, Bergmann, Mineraloge und grundlegender Geologe, cited below. In particular, see Dissertatio de consensu partium corporis humani occasione spasmi singularis in manu eiusque digitis ex hernia observati (Wittenberg, 1741); “Sammlung einiger mineralischer Merkwürdigkeiten des Plauischen Grundes bey Dressden,” in Neue Versuche nützlicher Sammlungen (1749, 580-597); Abhandlung von Phosphoris (Dresden-Leipzig, 1750); Kurtze Nachricht vom Erbbereiten (Dresden-Leipzig, 1750); Kurtze Einleitung in einige Theile der Bergwerks-Wissenschaft (Berlin, 1751); “Ohnmassgeblicher Vorschlag, auf was Art und Weise man zu einer genaueren Entdeckung der unter der Erde verborgenen Dinge, oder kurz zu sagen, zu einer unterirdischen Erdbeschreibung gelangen könne,” in PhysikalischeBelustigungen,, 2 (1752), 27-42; Abhandlung von den Metallmüttern (Berlin, 1753); Versuch einer Geschichte von Flötz-Gebürgen (Berlin, 1756); Physicalische Gedanken von denen Ursachen derer Erdbeben (Berlin, 1757); “Histoire du Chrysoprase de Kosemitz,” in Histoire de l’Académie de Berlin, 11 (1757), 202-214; Kurzer Entwurf einer Mineralogie (Berlin, 1758); Cadmiologia, pt. 1 (Berlin, 1760); Probierkunst (Berlin, 1761); Physikalisch-chymische Schriften (Berlin, 1761); Specimen orographiae generalis tractus montium primarios globum nostrum terraqueum pervagantes (St. Petersburg, 1762); Cadmiologia, pt. 2 (Königsberg-Leipzig, 1766); De nova minerae plumbi specie crystallina rubra (St. Petersburg, 1766); “Historia et examen chymicum lapidis nephritici,” in Novi commentarii Academiae [of St. Petersburg], 10 (1766), 381-412; “De vitro fossili naturali sive de Achate Islandico,” ibid., 12 (1768), 356-367; “De Cupro et Orichalco magnetico,” ibid., 368-390; and “Specimen Oryctographiae Stara–Russiensis et lacus Ilmen,” ibid., 391-402.
II. Secondary Literature. Works about Lehmann include Bruno von Freyberg, Die geologische Erforschung Thüringens in älterer Zeit (Berlin, 1932); Neues über Johann Gottlob Lehmann (Erlangen, 1948); and Johann Gottlob Lehmann, ein Arzt, Chemiker, Metallurg, Bergmann, Mineraloge und grundlegender Geologe, vol. I of Erlanger Forschungen B, (Erlanger, 1955); W. von Gümbel, “Johann Gottlob Lehmann,” in Allgemeine deutsche Biographie,, XVIII (Leipzig, 1883), 140-141; and Hans Prescher, “Johann Gottlob Lehmann (1719-1767). Zum 200. Todestage des bedeutenden Bergmanns, Metallurgen und Begründers der modernen Erdgeschichtsforschung,” in Der Anschnitt, 19 (1967), 9-18, See also Poggendorff, I, 1409-1416.
Bruno von Freyberg