Haidinger, Wilhelm Karl

(b. Vienna, Austria, 5 February 1795; d. Dornbach, near Vienna, 19 March 1871)

mineralogy geology.

After a basic education in Vienna, Haidinger in 1812 went to Graz, where he worked as an assistant, lodging in the home of Friedrich Mohs, professor of mineralogy at the recently established Landesmuseum Joanneum. They made frequent excursions in the adjacent mining regions, meeting A. G. Werner at Freiberg in 1816. In the company of Count Breunner (after whom he named the mineral breunnerite), Haidinger visited Georges Cuvier and J.-B. Biot at Paris and George Greenough, David Brewster, and Thomas Allan (a banker interested in mineralogy) at Edinburgh. In 1823 Haidinger moved to Edinburgh in order to arrange Allan’s mineral collection. There he began publishing on the determination of mineral species, his first work being a translation, with many additions, of Mohs’s famous textbook (1825), expounding for English readers what could be achieved in natural history through mineral determination and classification. The complications arising from isomorphism and polymorphism, then being clarified by Eilhard Mitscherlich and J. J. Berzelius, were still a stumbling block for Haidinger. Between 1827 and 1840 he worked in a china factory that had been founded by his two brothers in Elbogen. In 1840 he was appointed an inspector of mines (Bergrath) in Vienna.

Around 1827 Haidinger’s chief interest turned to pseudomorphs, since they are one of the few unambiguous indicators of a mineral change that must have taken place in the past. Following Humphry Davy, he attributed the motion and replacement of particles to electrochemical forces, drawing a parallel between this interchange of constituents and the behavior of a solution in electrolytic dissociation. The calcite-dolomite transformation led Haidinger (1848) to the hypothesis that percolating saline solutions (Gebirgsfeuchtigkeit) containing MgSO₄ replace 2CaCO₃ by CaCO₃+MgCO₃ molecules. This process was thought to proceed at elevated pressure and temperature, with precipitation of gypsum. Most of the gypsum would be taken into solution and redeposited at greater depths. Under surface conditions the reverse reaction occurs, that is, dedolomitization, with lime replacing magnesium. This hypothesis was verified experimentally by the more geology-minded Charles von Morlet, who used a gun barrel equipped with inlet and outlet valves.

Haidinger also studied the absorption of light in crystals, most likely an interest acquired from Brewster during his Edinburgh period. He designed a charmingly simple and effective instrument (1848) that was later named Haidinger’s dichroscope. With its aid Haidinger made many delicate observations of pleochroic minerals, first only with transmitted light, then also with reflected light. Observations on the connection between absorption and the direction of polarization of transmitted and reflected light led in 1848 to a well-founded theory bearing on Babinet’s rule that a greater absorption (of the whole spectrum of visible light) corresponds to a higher index of refraction. Babinet’s rule also tempted Haidinger to suggest a possible arrangement and “bonding” of iron particles in a crystal structure that was based on peculiar absorption phenomena (1855). Clearly aware that only the direction of vibration, and not the direction of propagation of the light, decides the degree to which light is absorbed by the crystal, Haidinger reached the fundamental conclusion (1852) that for linearly polarized light, the direction of vibration in the ether must be perpendicular to the direction of propagation—a conclusion leading to a coherent picture of the optical behavior of transparent crystals which is still followed in all treatises on this subject that are not sophisticated enough to identify this direction with the electric vector E.

At the Hof Mineralien Cabinet in Vienna, where Moritz Hoernes often received meteorites and information about them, Haidinger began to publish on these acquisitions in 1847. At first limited to mineralogical composition, this work later also considered the phenomena of light and sound emitted by meteorites when traversing the atmosphere and hitting the ground. His results, together with observations of the angles of incidence and depths of penetration, led to a summary and noteworthy explanation of these phenomena (1861). In the same publication, probably loath to lag behind his contemporaries, Haidinger ventured a theory on the origin of meteorites. He postulated an original Weltkörper made up of collected cold cosmic dust, which had been created out of nothing, and was subsequently heated through pressure and friction of the component particles. Differential internal tension caused an explosion of the body, flinging the resulting fragments apart.

Although not originally a geologist, Haidinger obstinately urged the need to create a geological survey, which in 1849 was established under the patronage of the royal and imperial Vienna Academy of Sciences. Haidinger, a member of the Academy since its founding, was appointed the first director of the geological Reichsanstalt. He was always respectful toward the authorities and grateful when he or his Anstalt was honored or praised, a situation that occurred frequently in later years. After a long illness Haidinger was granted a pension in 1866, upon which he moved to Dornbach, where he spent the last five years of his life.

BIBLIOGRAPHY

I. Original Works. Haidinger’s writings include Treatise on Mineralogy, 3 vols. (Edinburgh, 1825), his trans. of Mohs’s textbook; “On the Determination of the Species in Mineralogy,” in Transactions of the Royal Society of Edinburgh, 10 (1826), 298–313; “On the Parasitic Formation of Mineral Species,” ibid.,11 (1831), 73–114; “Ueber die dichroskopische Loupe,” in Sitzungsberichte der k. Akademie der Wissenschaften in Wien, Nat-math. Kl., 1 (1848), 131–137; “Ueber den Zusammenhang des orientirten Flächenschillers mit der Lichtabsorption farbirger Krystalle,” ibid., 146–152; “Ueber Herrn von Morlot’s Sendschreiben an Herrn Élie de Beaumont die Bildung des Dolomits betreffend,” ibid., 171–173; “Ueber die Richtung der Schwingungen des Lichtaethers im geradlinig polarisierten Lichte,” in Poggendorffs Annalen der Physik, 86 (1852), 131–144; “Die grüne Farbe der oxalsauren Eisenoxyd-Alkalien und die weisse der Eisenoxyd-Alaune,” ibid., 94 (1855), 246–255; and “Ueber die Natur der Meteoriten in ihrer Zusammensetzung und Erscheinung,” in Stizungsberichte der k. Akademie der Wissenschaften in Wien, Nat-math Kl., 2nd ser. 43 (1861), 389–426.

II. Secondary Literature. On Haidinger or his work, see “Die Haidinger Medaille,” in Jahrbuch der k. k. Geologischen Reichsanstalt, 6 (1856), v-xix; F. von Hauer, “Zur Erinnerung an Wilhelm Haidinger,” ibid., 21 (1871), 31–41; and A. Johannsen, A Descriptive Petrology of Igne, ous Rocks (Chicago, 1938), 11, 72, with portrait.

Joyce Wevers