THE SALTS OF THK SEA. 257 



attains the exact degree of specific gravity due to sea water 

 generally. 



48 G. Solid matter secreted hij them. — How much solid matter 

 does the whole host of marine plants and animals abstract from 

 sea water daily? Is it a thousand pounds, or a thousand millions 

 of tons ? No one can say. But, whatever be its weight, it is so 

 much of the power of gravity applied to the dynamical forces of 

 the ocean. And this power is derived from the salts of the sea, 

 through the agency of sea-shells and other marine animals, that of 

 themselves scarcely possess the power of locomotion. Yet they 

 have power to put the whole sea in motion, from the equator to 

 the poles, and from top to bottom. But we have yet to inquire 

 how far may currents be due to the derangement of equilibrium 

 arising from the change of specific gravity caused by the secretions 

 of the myriads of marine animals that are continually at work in 

 various parts of the ocean. These little creatures abstract from 

 sea water solid matter enough to build continents of. And, also, 

 we have to remember as to the extent to v/hich equilibrium in the- 

 sea is disturbed by the salts which evaporation leaves behind. 

 Thus, when we consider the salts of Ihe sea in one point of view, 

 we see the winds and the marine animals operating upon the 

 waters, and, in certain parts of the ocean, developing by their 

 action upon the solid contents of the same those very principles 

 of antagonistic forces which hold the earth in its orbit, and pre- 

 serve the harmonies of the imiverse. 



487. Dynamical force derived from. — ^From another point of 

 view, we see the sea-breeze and the sea-shell, in performing 

 their appointed offices, so acting as to give rise to a reciprocating 

 motion in the waters; and thus they impart to the ocean dy- 

 namical forces also for its circulation. The sea-breeze plays 

 upon the surface ; it converts only fresh water into vapour, and 

 leaves the solid matter behind. The surface water thus becomes 

 specifically heavier, and sinks. On the other hand, the little 

 marine architect below, as he works upon his coral edifice at the 

 bottom, abstracts from the water there a portion of its solid con- 

 tents ; it therefore becomes specifically lighter, and up it goes, 

 ascending to the top with increased velocity, to take the place of 

 the descending column, which, by the action of the winds, has 

 been sent down loaded with fresh food and materials for the busy 

 little mason in the depths below. Seeing, then, that the inhabit- 

 ants of the sea, with their powers of secretion, are comiietent to 



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