404 VOLTAIC ACTION, AND 



two or three thousand feet of rocks or lava, 

 earthquakes would follow. 



It was before stated, that the rapidity with 

 which acid, alkaline, and other solutions are 

 decomposed by the plates of the battery, is aug- 

 mented by increasing their temperature, that 

 the amount of chemical action, like that of 

 evaporation and rain, is greatest on the surface 

 of the earth within the tropics, cceteris paribus; 

 and diminishes as we approach the regions of 

 perpetual frost. 



The same thing would seem to be true of 

 subterranean chemical action : which points out 

 the agency of solar heat in the production of 

 volcanos, and connects the whole theory of geo- 

 logical dynamics with that of solution, combus- 

 tion, and of universal chemistry. It is a re- 

 markable fact, which has never been explained 

 by geologists, that the highest mountains of the 

 earth are within the torrid zone, where they rise 

 to an elevation of from four to five miles above 

 the ocean level ; while in the middle latitudes 

 they do not exceed the height of fifteen or six- 

 teen thousand feet ; and not more than five or 

 six thousand feet beyond the polar circles, al- 

 though they are nearer to the centre of the globe 

 than any other part of its surface. The islands 

 of the Pacific and Atlantic oceans are also far 

 more numerous within the tropical than the 

 higher latitudes ; while it is certain that nearly 



