THE SALTS OF TPIE SEA. 165 



oi the universe by virtue of its saltness, and wiiich it could not 

 perform were its waters altogether fresh. And thus philosophers 

 have a clew placed in their hands which will probably guide them 

 to one of the many hidden reasons that are embraced in the true 

 answer to the question, " Why is the sea salt ?" 



329. Sea Shells. — We find in sea water other matter besides 

 common salt. Lime is dissolved by the rains and the rivers, and 

 emptied in vast quantities into the ocean. Out of it, coral islands 

 and coral reefs of great extent — marl-beds, shell-banks, and in- 

 fusorial deposits of enormous magnitude have been constructed by 

 the inhabitants of the deep. These creatures are endowed with 

 the power of secreting, apparently for their own purposes only, 

 solid matter, which the waters of the sea hold in solution. But 

 this power was given to them that they also might fulfill the part 

 assigned them in the economy of the universe. For to them., 

 probably, has been allotted the important office of assisting in 

 giving circulation to the ocean, of helping to regulate the cli- 

 mates of the earth, and of preserving the purity of the sea. 



330. The better to comprehend how such creatures m^ay influ- 

 ence currents and climates, let us suppose the ocean to be per- 

 fectly at rest — that throughout, it is in a state of complete equi- 

 librium — that, with the exception of those tenants of the deep 

 which have the power of extracting from it the solid matter held 

 in solution, there is no agent in nature capable of disturbing that 

 equilibrium — and that all these fish, &c., have suspended their se- 

 cretions, in order that this state of a perfect aqueous equilibrium 

 and repose throughout the sea might be attained. 



In this state of things — the waters of the sea being in perfect 

 equilibrium — a single mollusk or coralline, we will suppose, com- 

 mences his secretions, and abstracts from the sea water (§ 293) 

 solid matter for his cell. In that act, this animal has destroyed 

 the equilibrium of the whole ocean, for the specific gravity of 

 that portion of water from which this solid matter has been ab- 

 stracted is altered. Having lost a portion of its solid contents, it 

 has become specifically lighter than it was before ; it must, there- 

 fore, give place to the pressure which the heavier water exerts to 

 push it aside and to occupy its place, and it must consequently 

 travel about and mingle with the waters of the other parts of the 

 ocean until its proportion of solid matter is returned to it, and 



