406 THE CHEMISTRY OF CREATION. 



feeble, and roll down the shores of countries 

 lying in latitudes far remote. There can be 

 little question that, were the present relation 

 altered, that alteration would speedily be at- 

 tended with a modification of climate, and, 

 as a result, with important alterations in the 

 number and varieties of the animals and plants 

 occupying the surface of the present earth. 



The ocean is the great reservoir from whence, 

 raised by the process of evaporation, the earth 

 derives its supply of water, and to which all 

 springs and rivers carry back their contents. 

 A system of circulation is thus established on 

 the grandest scale. Water rises as vapour from 

 the ocean, assumes the form of clouds, descends 

 on land in the various conditions of rain, hail, 

 snow, and dew ; and becoming then collected 

 in larger currents, seeks the ocean again, to 

 undergo again the same series of changes. A 

 small portion of the saline contents of the sea 

 are thus made available to the necessities of 

 plants on land, by uniting with the ascending 

 vapour, and being precipitated in the descend- 

 ing shower. 



