THE END IN VIEW. 423 



stratum of salt-water, and an overlying stratum of 

 fresh- water. 



It is not clearly ascertained what are the 

 precise objects in view in the saline constitution 

 of the ocean. The presence of the salts is use- 

 ful in checking evaporation to too large an 

 extent ; in causing sea-water to freeze at a lower 

 temperature than fresh-water, at 2S Fahr. 

 instead of 32, thus rendering it more difficult 

 to solidify its surface than if it contained less 

 saline matter; and is also useful in communi- 

 cating to sea-water a greater buoyant power than 

 fresh-water. It likewise renders its putrefaction 

 less easy than if it were fresh. As we shall have 

 again to remark, there exists a strict connexion 

 between the functions of the tenants of the deep 

 and this saline matter. If, therefore, we are to 

 regard the presence of certain principles in the 

 air satisfactorily accounted for by the recogni- 

 tion of their usefulness to animals and plants, the 

 same reasoning may be applied to the ocean ; and 

 we may with justice regard its saline contents as 

 specially adapted to the functions and purposes of 

 its varied inhabitants. 



In addition to the saline matter, a trace of 

 organic matter is generally obtained in the 

 analyses of sea-water. This organic matter 

 may be due to minute animalcules, or it may 

 consist simply of some products of animal 



