At the age of sixteen, in the year 1790, Leopold von Buch was placed under Werner's care at the mining school of Freiberg. Werner found him a pupil after his own heart. Warmly adopting his teacher's theory, he pursued his geological studies with the greatest ardor, and continued for some time under the immediate influence and guidance of the Freiberg professor. His university-studies over, however, he began to pursue his investigations independently, and his geological excursions led him into Italy, where his confidence in the truth of Werner's theory began to be shaken. A subsequent visit to the region of extinct volcanoes in Auvergne, in the South of France, convinced him that the aqueous theory was at least partially wrong, and that fire had been an active agent in the rock-formations of past times. This result did not change the convictions of his master, Werner, who was too old or too prejudiced to accept the later views, which were nevertheless the result of the stimulus he himself had given to geological investigations.
But Von Buch was indefatigable. For years he lived the life of an itinerant geologist. With a shirt and a pair of stockings in his pocket and a geological hammer in his hand he travelled all over Europe on foot. The results of his foot-journey to Scandinavia were among his most important contributions to geology. He went also to the Canary Islands; and it is in his extensive work on the geological formations of these islands that he showed conclusively not only the Plutonic character of all unstratified rocks, but also that to their action upon the stratified deposits the inequalities of the earth's surface are chiefly due. He first demonstrated that the melted masses within the earth had upheaved the materials deposited in layers upon its surface, and had thus formed the mountains.
No geologist has ever collected a larger amount of facts than Von Buch, and to him we owe a great reform not only in geological principles, but in methods of study also. An amusing anecdote is told of him, as illustrating his untiring devotion to his scientific pursuits. In studying the rocks, he had become engaged also in the investigation of the fossils contained in them. He was at one time especially interested in the _Terebratulæ_ (fossil shells), and one evening in Berlin, where he was engaged in the study of these remains, he came across a notice in a Swedish work of a particular species of that family which he could not readily identify without seeing the original specimens. The next morning Von Buch was missing, and as he had invited guests to dine with him, some anxiety was felt on account of his non-appearance. On inquiry, it was found that he was already far on his way to Sweden: he had started by daylight on a pilgrimage after the new, or rather the old, _Terebratula_. I tell the story as I heard it from one of the disappointed guests.