THE SALTS OF THE SEA. ' 249 



stance, let us suppose the waters in a certain part of the torrid 

 zone to be 90"", but, by reason of the fresh water which has been 

 taken from them in a state of vapoui*, and consequently by reason 

 of the proportionate increase of salts, these waters are heavier than 

 waters that may be cooler, but not so salt (§ 105). This being the 

 case, the tendency would be for this warm, but salt and heayy 

 water, to flow off as an under current towards the polar or some 

 other regions of lighter water ; but these creatm'es take from it 

 a portion of these salts for their 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 may 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 giving 

 diversity to its chmates ; neither could evaporation give dynamical 

 force to its circulation; its waters, ceasing to contract as their 

 temperature falls below SO"", would give but little impulse to its 

 currents, and impart no motion (§ 404) to its waters in the depths 

 below : thus its circidation 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 gravity might have been greater even than that of extra- 

 tropical sea water generally at 28°. Notwithstanding this, after 

 traveUing 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 sm-face through the instrumentahty 

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

 depths of the ocean. Thus we perceive that these creatiu-es, 



