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returned anew, whenever in South America, or 

 in Mexico, I had occasion to examine volcanic 

 mountains. If we reflect on the little progress, 

 which the labours of mineralogists, and the dis- 

 coveries in chemistry, have made toward the 

 knowledge of the physical geology of mountains, 

 we cannot help being affected with a painful 

 sentiment ; and this is felt still more strongly by 

 those, who, questioning nature under different 

 climates, are more occupied by the problems 

 they have not been able to solve, than with the 

 small number of results they have obtained. 



The Peak of Ayadyrma, or of Echeyde*, is a 

 conic and isolated mountain, placed in an islet 

 of very small circumference. The learned, who 

 do not take into consideration the whole surface 

 of the Globe, believe, that these three circum- 

 stances are common to the greater part of vol- 

 canoes. They cite, in support of their opinion, 

 Etna, the Peak of the Azores, the Solfatara of 

 Guadaloupe, the Trois-Salazes of the Isle of 

 Bourbon, and that archipelago of volcanoes con- 

 tained in the Indian Sea and the Great Ocean. 

 In Europe and in Asia, as far as the interior of 

 the latter continent is known, no burning vol- 

 cano is situate in a chain of mountains ; all being 

 at a greater or less distance from these chains. 



* The word Echeyde, which signifies Hell in the language 

 of the Guanches, has been corrupted by the Europeans into 

 Teyde. 



