Leopold Von Bith, a German geologist, born at Stolpe, April 25, 1774, died in Berlin, March 4, 1853. At the age of 16 he was placed at the mining academy of Freiberg, where Alexander von Humboldt was among his fellow students. Von Buch made rapid progress, and manifested a peculiar aptitude for geological studies, as well as mineralogy. In 1797 he published Ver-such einer mineralogischen Beschreibung von Landeck, in which he gave the results of his mineralogical and geological investigations of the mountains of Silesia, which had never previously been systematically explored. Werner, the director of the academy, had propounded the Neptunian theory of geological formation, and Von Buch warmly espoused it. In his first investigations he classed basalt, gneiss, and mica schist among the aqueous formations. In 1797 Von Buch explored the Styrian Alps, while Humboldt was engaged in meteorological and eudiometrical researches in the same regions. In the spring of 1798 Von Buch pursued his geological excursions into Italy, and his investigations there unsettled his convictions of the truth of Werner's Neptunian theory; he inclined to the belief that the leucitic and pyrox-enic varieties of basaltic rocks' must be of igneous formation.

In 1799 he went to Naples, and saw Mount Vesuvius, which he revisited on Aug. 12, 1805, in company with Humboldt and Gay-Lussac, at the time of an eruption. In 1802 he visited the south of France and explored the regions of extinct volcanoes in Au-vergne. The general aspect of the Puy-de-Dome, with its cone of trachyte rock and its beds of basaltic lava, convinced him of the natural facts of igneous formations, and induced him to abandon Werner's exclusive doctrines of aqueous formation. ' The results of these geological researches were published in his Geognostische Beobachtungen auf Reisen (lurch Deutschland und Italien (2 vols. 8vo, Berlin, 1802-'9). From the south of Europe Von Buch turned to the north, and from July, 1806, to October, 1808, he explored the Scandinavian regions, carrying his investigations as far as the North cape. The results of these researches were some very important discoveries with regard to the geological formation of the crust of the earth, the climatology of different regions, and the geographical distribution of plants. Von Buch was the first to suggest the idea of the slow and gradual elevation of the land of Sweden above the level of the sea.

The results of these explorations were published in his Reise durch Norwegen und Lapp-land (2 vols. 8vo, 1810). His explorations of the Alps in Switzerland, and of the mountains of Germany, induced Von Buch to put forth the opinion that the highest chains of mountains have never been covered by the sea, but are the result of successive upheavings through fissures of the earth's crust, the parallel direction of which is indicated by the principal chains of mountains in the Alps. This suggestion had already been made by Avicen-na, and it has since been developed into a general theory by Elie de Beaumont. About this time, also, Von Buch published his views, which have since been confirmed by the labors of Noggerath, with regard to the formation of amygdaloid agates, or almond stones, in the porosities of melaphyre. In 1815 Von Buch went to the Canary islands, accompanied by Christian Smith, the Norwegian botanist. The volcanic islands, with the gigantic peak of Teneriffe, became the basis of an elaborate series of investigations on the nature of volcanic activity, and the results produced by fire, which he published in his Physikalische Be-schreibung der Canarischen Inseln (1825). He next visited the basaltic group of the Hebrides and the coasts of Ireland and Scotland. He continued his geological excursions and investigations until almost the last day of his life.

Eight months before he died he made another visit to the extinct volcanic region of Auvergne. His life was one continued round of observation, travel, and investigation. His journeys and explorations were made mostly on foot; with a change of linen and a geological hammer, he was equipped for any journey. Alexander von Humboldt styled him " the greatest geologist of the age." A catalogue of his numerous writings is given by Bone in the almanac of the Vienna academy of sciences for 1853.