604 HISTORY OF GEOLOGY. 



phenomena was apprehended. The person who first 

 looked at such operations with that commanding 

 general view which showed their extensive con- 

 nexion with physical geology, was Alexander von 

 Humboldt, who explored the volcanic phenomena of 

 the New World, from 1799 to 1804. He remarked ' 

 the linear distribution of volcanic domes, consider- 

 ing them as vents placed along the edge of vast 

 fissures communicating with reservoirs of igneous 

 matter, and extending across whole continents. He 

 observed, also, the frequent sympathy of volcanic 

 and terremotive action in remote districts of the 

 earth's surface, thus showing how deeply seated 

 must be the cause of these convulsions. These 

 views strongly excited and influenced the specula- 

 tions of geologists ; and since then, phenomena of 

 this kind have been collected into a general view as 

 parts of a natural historical science. Von Hoff, in 

 the second volume of the work already mentioned, 

 was one of the first who did this ; " At least," he 

 himself says% (1824,) "it was not known to him 

 that any one before him had endeavoured to com- 

 bine so large a mass of facts with the general ideas 

 of the natural philosopher, so as to form a whole." 

 Other attempts were, however, soon made. In 

 1825, M. von Ungern-Sternberg published his book 

 On the Nature and Origin of Volcanoes*, in which, 



' Humboklt, Rdation H istor ique ; and his other works. 



2 Vol. ii. Prop. 5. 



3 Werden und Seyn des Vrdkanischen Gebirges, Carlsruhc, 1825. 





