THE SALTS OF THE SEA. 259 



from it a portion of these salts for tlieir own purposes, and so 

 make it light enough to flow off on the surface instead of the 

 bottom — it then goes polar- ward, dispensing warmth and moisture 

 as it goes; and so climate ma}'. be influenced. Moreover, if the 

 sea were not salt, there would be no coral islands to beautify its 

 landscapes and give variety to its features ; sea-shells and marine 

 insects could not operate upon the specific gravity of its waters, 

 nor assist in giviug diversity to its climates ; neither could 

 evaporation give dynamical force to its circulation; its waters, 

 ceasing to contract as their temperature falls below 39"^, would 

 give but little impulse to its currents, and impart no motion 

 (§ 404) to its waters in the depths below : thus its circulation 

 would be torpid, and its bosom lack animation. In some other 

 parts of the ocean, instead of there being organic life capable of 

 changing, by animal or vegetable secretions, the specific gravity 

 of the supposed salt and heavy and hot water at 90^, there may 

 be none such, as in a *' Desolate Eegion." This water then may 

 go off as an under-current freighted with heat to temper some 

 hyperborean region or to soften some extra-tropical climate, for 

 we know that such is among the effects of marine currents. At 

 starting, it might have been, if you please, so loaded with solid 

 matter that, though its temperature were 90°, yet, by reason of 

 the quantity of such matter held in solution, its specific gi-avity 

 might have been greater even than that of extra-tropical sea 

 water generally at 28°. Notwithstanding this, after travelling 

 below to certain latitudes, it may be brought into contact by the 

 way, with those kinds and quantities of marine organisms that 

 shall abstract solid matter enough to reduce its specific gravity, 

 and, instead of leaving it greater than common sea water at 

 28°, make it less than common sea water at 40° ; consequently, in 

 such a case, this warm sea water, when it comes to the cold lati- 

 tudes, would be brought to the surface through the instrumentality 

 of shell-fish, and various other tribes that dwell far down in the 

 depths of the ocean. Thus we perceive that these creatures, 

 though they are regarded as beings so low in the scale of creation, 

 may nevertheless be regarded as agents of much importance in 

 the terrestrial economy ; for we now comprehend how they are 

 capable of spreading over certain parts of the ocean those benign 

 mantles of %varmth Avhich temper the winds, and modify, more or 

 less, all the marine climates of the earth. 



489. The regulators of the sea. — The makers of nice astronomical 



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