ON VOLCANOES AND EARTHQUAKES. 371 



the lowest knowledge of chemistry, deserve none. 

 These theories have been contrived because it was 

 supposed that certain fusible minerals contained in 

 Volcanic products, were crystals that had been ejected 

 in that state; whereas they are the produce of igneous 

 fusion and slow cooling, of affinities exerted in a com- 

 pound fluid mass of earths. Thus does ignorance 

 generate folly. That the phenomena of Volcanoes 

 all indicate an intense heat, would be as superfluous 

 to prove, as it would be to show that those lavas 

 which once formed uniform fluids resembling glass, 

 are now crystallized rocks of an infinite diversity of 

 character. Of the theories of Thomson and Patrin, 

 one of them is impossible and the other unintelligible; 

 but there are two other hypotheses which demand 

 more notice, as the last also is probably the true one. 

 Since it has been known that the earths and al- 

 kalies were the oxydes of metallic substances, it has 

 been supposed that the admission of water to repo- 

 sitories containing their metallic bases, was adequate 

 to the solution of volcanic phenomena. This hypo- 

 thesis has a merit which must be refused to all the 

 others, because its chemistry is true. But it does not 

 provide for the perpetual heat maintained in volcanic 

 regions, nor for the long intervals of repose, nor for 

 the production of new volcanoes. Water must be 

 admitted in stated modes to produce these effects; 

 and there is no agent to provide for its admission, or 

 to open the fissures through which it must flow upon 

 these inflammable substances. But a more serious 

 objection arises from considering the nature and abun- 

 dance of the unstratified rocks, of which the origin is 

 similar to that of volcanic substances. It is plain, 

 that to form all the granite and trap of the earth, an 

 enormous quantity of water must have been con- 



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