BUCH, boon, Leopold von, German geol ogist: b. Stolpe, Prussia, 26 April 1774; d. Berlin, 4 March 1853. He studied under the celebrated Werner in the mining school of Freiberg in Saxony, where Alexander von Hum boldt was his fellow-student, and early began to distinguish himself by his geological writ ings. His first works were 'Descriptions of the Mineralogy of Landeck) and 'The Geognosy of Silesia.' Up to 1798 he had adopted the Nep tunian theory of Werner, with some modifica tions; but now saw cause to abandon it, and to recognize the volcanic origin of the basalts. He saw Vesuvius for the first time in 1799; but afterward, in 1805, had an opportunity, along with Humboldt and Gay Lussac, of witnessing its actual eruption. In 1802 he examined the extinct volcanoes of Auvergne in the south of France. The results of all these geological travels were given to the world in a work en titled 'Observations. During Travels in Ger many and Italy' (1802-09). Indefatigable as an observer, Von Buch turned his steps from the south of France in 1806, and proceeding to Scandinavia spent two years in examining its physical constitution. This furnished the ma terials for his well-known work entitled 'Travels in Norway and Lapland) In 1815 he visited the Canary Islands. These volcanic
isles furnished the starting point from which Von Buch commenced a regular course of study on the production and activity of vol canoes. This is attested by his standard work on the subject entitled 'Physical Description of the Canary Isles' (1825). On his return from the Canaries he visited the basaltic group of the Hebrides and the coasts of Scotland and Ire land. His geological excursions, even in coun tries which he had repeatedly visited before, continued without interruption at a very ad vanced age, till within a few months of his death. Alexander von Humboldt, who had known him intimately for a period of more than 60 years, called him the greatest geologist of our period. He was unmarried and lived aloof from the world, entirely devoted to scientific pursuits. Besides the works already mentioned he was the author of many important tracts on paleontology, as, 'On the Ammonites' (1832) ; 'On the Terebratulx) (1834) ; 'On the Ceratites' (1841) ; and 'On the Cystidm) (1845). Another of his works not to be omit ter is his 'Geological Map of Germany.'