178 Things not generally Known. 



organic impurities in a vast body of moving water, whether 

 fresh or salt, become rapidly lost, so as apparently to have 

 called forth a special agency to arrest the total organised matter 

 in its final oscillation between the organic and inorganic worlds. 

 Thus countless hosts of microscopic creatures swarm in most 

 waters, their principal function being, as Professor Owen sur- 

 mises, to feed upon and thus restore to the living chain the 

 almost unorganised matter of various zones. These creatures 

 preying upon one another, and being preyed upon by others in 

 their turn, the circulation of organic matter is kept up. If we 

 do not adopt this view, we must at least look upon the Infuso- 

 ria and Foramiuifera as scavenger agents to prevent an undue 

 accumulation of decaying matter ; and thus the salt condition 

 of the sea is not a necessity. 



Nor is the amount of saline matter in the sea sufficient to 

 arrest decomposition. That the sea is salt to render it of 

 greater density, and by lowering its freezing point to preserve 

 it from congelation to within a shorter distance of the poles, 

 though admissible, scarcely meets the entire solution of the 

 question. The freezing point of sea-water, for instance, is only 

 877 F. lower than that of fresh water ; hence, with the present 

 distribution of land and sea and still less, probably, with that 

 which obtained in former geological epochs no very important 

 effects would have resulted had the ocean been fresh instead of 

 salt. 



Now Professor Chapman, of Toronto, suggests that the salt 

 condition of the sea is mainly intended to regulate evaporation, 

 and to prevent an undue excess of that phenomenon ; saturated 

 solutions evaporating more slowly than weak ones, and these 

 latter more slowly again than pure water. 



Here, then, we have a self-adjusting phenomenon and admir- 

 able contrivance in the balance of forces. If from any tempo- 

 rary cause there be an unusual amount of saline matter in the 

 sea, evaporation goes on the more and more slowly ; and, on 

 the other hand, if this proportion be reduced by the addition of 

 fresh water in undue excess, the evaporating power is the more 

 and more increased thus aiding time, in either instance, to 

 restore the balance. The perfect system of oceanic circulation 

 may be ascribed, in a great degree at least, if not wholly, to 

 the effect produced by the salts of the sea upon the mobility and 

 circulation of its waters. 



Now this is an office which the sea performs in the eco- 

 nomy of the universe by virtue of its saltness, and which it 

 could not perform were its waters altogether fresh. And thus 

 philosophers have a clue placed in their hands which will pro- 

 bably guide to one of the many hidden reasons that are em- 

 braced in the true answer to the question, " Why is the sea salt , ? " 



