538 THE UNIVERSE. 



The globe on fire, and launched into space, necessarily 

 obeyed the laws of the radiation of heat, and when, after a 

 long succession of ages, it had sufficiently cooled down, its 

 surface became solidified, and constituted the primitive crust. 



When this cooling down had made sufficient progress, the 

 vapors from the earth, an immense atmosphere of which 

 enveloped the globe, became condensed, and poured over 

 the surface in torrents of rain. Gleams of lightning and in- 

 cessant peals of thunder accompanied these imposing scenes 

 of the birth of our globe, of which our imagination will 

 never yield us more than an imperfect image. Such was 

 the origin of the first seas. 



At the same time that, in the course of ages, the crust of 

 the earth augmented in thickness, the cooling down, by 

 contracting the globe, forced its envelope to yield and 

 break. These efforts produced the mountains which now 

 roughen its surface. 



Whilst the crust of the earth was yet thin, a slight effort 

 of the central heat sufficed to rupture it, but this only pro- 

 duced insignificant elevations. When this crust had ac- 

 quired sufficient firmness and thickness, its rupture, inas- 

 much as it demanded much greater force, was only effected 

 by means of the most violent plutonic movements ; it was 

 then that the Cordilleras rose into the clouds. 



The upheaval of each mountain chain was necessarily ac- 

 companied by enormous perturbations in the level of the 

 sea ; from thence came these grand scenes of deluges men- 

 tioned in the cosmogonies of all nations. These upheavals, 

 of which at least fifteen or sixteen have been made out, ter- 

 minated by the rising of the chain of the Andes, the result 



