276 Professor de la Rive o?t Electridty. 



nations, disruptions, the increase of temperature, elevation of 

 the surface by a kind of ebullition, and finally the formation of 

 solid matter, whensoever one of the compound products required 

 a very elevated temperature that it might remain in a liquid 

 state. It would only be after a great number of convulsions, 

 and in virtue of a subsequent refrigeration, that a crust could 

 be formed sufficiently solid to present an obstacle to new che- 

 mical combinations. But when the temperature should have 

 been so far depressed as to allow a new substance to come and 

 rest in a liquid state upon this solid bed, phenomena analogous 

 to those we have been alluding to would occur, either on this 

 bed, if it were of a suitable character, or on some inferior one, 

 which the liquid substance might reach through some fissures 

 in the first. New disruptions and explosions must have resulted 

 from this, which would, more or less, break the exterior solid 

 crust. 



Thus may we assign a reason for the successive revolutions 

 which the earth has experienced, and for the breaking up, and 

 the disposition in all sorts of inclination, of beds at first formed 

 in lines parallel to each other. 



We shall not follow the author in the details he supplies in 

 explaining the different catastrophes or cataclysms which the 

 surface of the earth must have undergone, and of the order in 

 which the different products of nature, whether vegetable or 

 animal, may have succeeded each other. We have already said 

 enough to show, which was the object we had in view, that the 

 existence of a solid nucleus is in no respect incompatible with the 

 manner in which we may suppose that the globe has been 

 formed, and may very well be reconciled with its being flattened 

 at the two poles. 



We shall only further add, that at a certain epoch of the re- 

 frigeration, water must necessarily have deposited itself upon 

 the whole of the solid crust of the globe, though, at the termina- 

 tion of the catastrophes and elevations which have resulted 

 from it, this water now covers only a portion of the surface of 

 the earth. It is this water which, now penetrating to the metaU 

 lie nucleus, and exerting a most active chemical agency on its 

 surface, produces the heat, the electrical currents and volcanoes. 

 Davy has already shewn that the phenomena which accompany 

 volcanic eruptions, as well as the properties of gases which 



