atid of the Phenomena of Volcanoes. 345 



views with the relation given of the creation in the Book of Ge- 

 nesis, and particularly with the order in which the several 

 classes of beings are there represented to have been successively 

 formed. 



Since the creation of man, he observes, the only catastrophe 

 which the globe has undergone is that which corresponds with 

 the Mosaic Deluge, to which perhaps may have been owing the 

 elevation of Himalaya and the Andes. At present the crust of 

 oxide which separates us from the non-oxidized nucleus is so 

 thick, that convulsions ai-e become very rare, and the resistance 

 opposed by it is so great, that when a fissure does take place, by 

 which a communication with the interior is brought about, the 

 explosion is only local, and its effects are not extended, as here- 

 tofore, over the entire globe ; so that, although the shock may 

 at times be propagated over a great extent, yet no actual frac- 

 ture of the solid covering, or ejection of melted matters over its 

 surface, will take place, except over a comparatively limited area. 



This hypothesis of an unoxidized nucleus, concludes our au- 

 thor, an idea at one time pronounced by Davy to be the only 

 admissible one, affords a ready explanation of the phenomena of 

 volcanoes, without rendering it necessary for us to suppose the 

 earth to possess an enormous heat derived from the state of fu- 

 sion in which its internal nucleus is by some imagined to be re- 

 tained. This very unoxidized mass, indeed, is in itself an inex- 

 haustible chemical source of heat, which will be developed each 

 time that another body enters into union with it with sufficient 

 energy ; so that an active volcano may be regarded as nothing 

 more than a permanent fissure in the globe, a constant channel 

 of communication between its unoxidized nucleus and the liquids 

 which lie above its oxidized crust. 



Every time these liquids penetrate to the unoxidized nucleus, 

 an elevation of the crust must take place from the mere increase 

 of volume, which a metallic substance experiences upon uniting 

 with oxygen. 



The heat resulting from the chemical action would have its 

 maximum of intensity at the point at which the union takes 

 place, i. e. along the line of contact between the oxidized portion 

 and the metallic nucleus, and must be propagated from thence, 



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