246 PHYSICAL GEOGRAPHY OF THE SEA, AND ITS METEOEOLOGY. 



tacle for the -waters brought into it by this micler current, which, 

 because it comes from towards the equatorial regions, comes from 

 a milder climate, and is therefore warmer, we can easily imagine 

 why there might be an open sea in the polar regions — why Lieu- 

 tenant De Haven, in his instructions (§ 428), was directed to look 

 for it ; and why both he and Captain Penny, of one of the Enghsh 

 searching vessels, and afterwards Dr. Kane, found it there. And 

 in accounting for this polynia, we see that its existence is not only 

 consistent with the h^^othesis with which we set out, touching a 

 perfect system of oceanic circulation, but that it may be ascribed, 

 in a great degree at least, if not wholly, to the effect produced by 

 the salts of the sea upon the mobihty and circulation of its waters. 

 Here, then, is an office which the sea performs in the economy of 

 the universe by virtue of its saltness, and w^hich it could not per- 

 form were its waters altogether fi'esh. And thus philosophers 

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

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

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



485. Sea Shells. — We find in sea water other matter (§ 48) be- 

 fnflueuce^fT^^^^"^ ^^^^^^ commou Salt. Lime is dissolved by the rains 

 curreiiti. 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 infusorial deposits of enormous magni- 

 tude, 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, w^hich the waters of the sea 

 hold in solution. But this power was given to them that they 

 also might fulfil the part assigned them in the economy of the 

 universe. For to them, probably, has been allotted the important 

 office of assisting to give circulation to the ocean, of helping to 

 regulate the climates of the earth, and of preser^dng the purity of 

 the sea. The better to comprehend how such creatm-es may in- 

 fluence currents and climates, let us again suppose the ocean to be 

 perfectly at rest — that throughout, it is in a state of complete 

 equihbrium — 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 natui'e capable of disturbing that equi- 

 hbrium — and that all these fish, etc., have suspended their secre- 

 tions, in order that tliis 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. 



