106 BOOK OF NATURE LAID OPEN. 



heat, it would be in clanger of putrefaction ; as we 

 advance northward, this quantity diminishes, till, at 

 the Pole, it nearly vanishes altogether. 



It may also be remarked, that the Caspian and 

 other inland seas, that have no effluent rivers to put 

 them in motion, and circulate their contents, are salt; 

 while the lakes of Ontario and Erie, through which 

 the river St. Lawrence passes, in North America, 

 are fresh-water lakes. 



We have already Had occasion to remark the bad 

 effects that must have inevitably ensued, had the 

 putrid carcases of land-animals been left to rot in 

 the air unburied; but what must this mighty recep- 

 tacle of carrion and putrefaction have long ere now 

 become, but for the correcting and renovating power 

 imparted to it by its saltness and motion. 



And it ought here to be remarked, that, from what- 

 ever cause the saline nature of the ocean may pro- 

 ceed, its saltness is as inherent in its composition as 

 the heat is in the sun; while, to preserve and keep 

 up the perpetual agitation of its fluid particles, its 

 motion is not dependant on any one single cause. 



The most perceptible agitation in this world of 

 water that strikes our senses, is that occasioned by 

 tl e influence of the wind, when the raging billows 

 heave their tumultuous throes, and threaten destruc- 

 tion to the affrighted mariner; yet this motion, even 

 in the most violent storms, is said to be confined 

 only to its surface That occasioned by the cur- 

 rents, however must descend to the bottom, and be 

 particularly strong among those narrow and deep 



