Volcanoes. 165 



those investigations which are directed to other branches of 

 natural science. This is a mistake into which nearly all 

 early scientific travellers fell. When they visited a foreign 

 country, they found themselves surrounded, both in the vege- 

 table and animal creation, with so many novel objects, that 

 they paid little or no regard to the physical and geological 

 characters of the district, but satisfied themselves and their 

 readers with a vague remark that it was more mountainous or 

 level than this or that portion of their native country ; and 

 was formed of granite or sandstone, resembling that which 

 occurred at some other specified place. But as soon as the 

 science of geology attracted the attention of naturalists, the 

 importance of an extensive observation of inanimate nature 

 was generally admitted; for it required little experience to 

 discover that by this means alone any knowledge could be 

 obtained of the superposition of rocks and their probable 

 formation. But in spite of the extended observations which 

 have been recorded, these problems are still hypothetical 

 points in geology, which cannot be satisfactorily determined 

 from the data we possess. Geology must be brought to the 

 simple but noble condition of a practical science; and, like 

 chemistry, watch over its accumulating facts, jealous of hypo- 

 thesis. So long as Stahl and Beccher haunted chemistry 

 with their phlogistic phantom, every phenomenon was wrapt 

 in the mist which it generated. But, in speaking of geology, 

 almost every author has found a world which can only exist 

 so long as it preserves the character which his imagination 

 has given it; and could not have existed at all, had it not been 

 formed according to his opinions. When geologists are cured 

 of the mania which has seized them, and turn their powerful 

 energies to the discovery of facts, our knowledge of volcanic 

 districts, and the phenomena which attend volcanic activity, 

 will proportionally increase ; for the geologist alone is capable 

 of making those observations upon which rational opinions can 

 be formed. There was a time, and it is almost within the 

 memory of some of our readers, when the mounts Etna and 

 Vesuvius were made the types of universal volcanic action ; 

 but the more extended observation of modern science has 

 already given us a juster conception of this subject, has 

 exposed many facts presumed to be connected with their 

 causes, and made us tolerably acquainted with their geological 

 position and periods of activity. 



There is no term more vaguely applied than the word vol- 

 cano. Sometimes it is used to signify hot springs ; at other 

 times, cones which eject mud, as at Turbaco in South Ame- 



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