64 HISTORY OF GEOLOGY AND PALEONTOLOGY. 



the other he moved in the first social circle in Berlin. Men 

 still live who can bear enthusiastic personal testimony to the 

 noble way in which Von Buch exerted this influence for the 

 benefit of science. After a short illness, he died in Berlin on 

 the 4th March, 1852. 



Leopold von Buch was rightly regarded as the greatest 

 geologist of his time. He had studied in every domain of 

 geology; he was familiar with a large part of Europe. Wher- 

 ever he went, he willingly and freely communicated his own 

 knowledge to others, and ever rejoiced to be able to assist by 

 his money or his influence any one in whom he detected a 

 true devotion to science. At the same time he had little 

 patience with men of mediocre ability, and was very severe 

 towards importunity of any kind. His ridicule was feared as 

 much as his praise was valued. He was an acute thinker and 

 wonderful observer, and possessed in a high degree the rare 

 gift of clear and elegant exposition. 



A complete edition of his works was published after his 

 death at Berlin (1867-77). 



Alexander von Humboldt, the friend and fellow-student of 

 Von Buch, although less illustrious as a geologist, had a more 

 versatile and philosophical turn of mind. Like Von Buch, 

 Humboldt belonged to an old aristocratic family. He was 

 born in Berlin in 1769, studied at first in Gottingen, afterwards 

 in 1791-92 with Werner at Freiberg. On the completion of 

 his studies he was made Director of Mines, and moved from 

 Bayreuth and Ansbach to Steben in the Fichtel mountains. 

 Several papers written by him during this period on " The 

 Magnetic Properties of Serpentine and other Rocks," attracted 

 the attention of mineralogists. In 1793 he visited the salt 

 mines in the Salzkammergut and Galicia, but in 1796 he 

 resigned his Government appointment, to follow out inde- 

 pendent lines of research. During the winter of 1797-98, when 

 he and Von Buch lived together in Salzburg, he made a series 

 of observations on meteorology and earth- magnetism, and 

 took barometric and trigonometric measurements of height. 



In a treatise published in 1799, Von Humboldt endeavoured 

 to explain the tropical climate of earlier geological periods by 

 a combination of the Laplace theory of heat with Werner's 

 views regarding the precipitation of the primitive rock 

 materials from aqueous solutions. And although his treatise 

 is almost forgotten in science, it contains a number of sug- 



