238 rnvsrcAL GEociiArnY of the sea, and its meteorology. 



464. Hypotheses. — In order to investigate the effect of the salts 

 of the sea upon its currents, and to catch a glimpse of the laws 

 b}" which the circulation of its waters is governed, hypothesis, in 

 the present meagre state of absolute knowledge with regard to 

 the subject, seems to be as necessary to progress as is a coi-ner- 

 stone to a building. To make progress with such investigations 

 we want something to build upon. In the absence of facts, we 

 are sometimes permitted to suppose them ; only, in supposing 

 them, we should take not only the possible, but the probable ; 

 and in making the selection of the various hypotheses which are 

 suggested, we are bound to prefer that one by which the greatest 

 number of phenomena can be reconciled. When we have found, 

 tried, and offered such a one, we are entitled to claim for it a 

 respectful consideration at least, until we discover it leading us 

 into some palpable absurdity, or until some other hypothesis be 

 suggested which will account equally as well, but for a greater 

 number of phenomena. Then, as honest searchers after truth, 

 we should be ready to give up the former, adopt the latter, and 

 hold it until some other better than either of the two be offered. 

 AMth this understanding, I venture to offer an hypothesis with 

 regard to the agency of the salts or solid matter of the sea in 

 imparting d^Tiamical force to the waters of the ocean, and to 

 suggest that one of the purposes which, in the grand design, it 

 was probably intended to accomplish by having the sea salt, and 

 not fresh, was to impart to its waters the forces and powers 

 necessary to make their circulation complete. In the first place, 

 we rely mainly upon hypothesis or conjecture for the assertion 

 that there is a set of currents in the sea by which its waters are 

 conveyed from place to place with regularity, certainty, and 

 order. But this conjecture appears to be founded on reason, and 

 we believe it to be true ; for if we take a sample of water which 

 shall fairly represent, in the proportion of its constituents, the 

 average water of the Pacific Ocean, and analyze it, and if we do 

 the same by a similar sample from the Atlantic, we shall find the 

 analysis of the one to resemble that of the other as closely as 

 though the two samples had been taken from the same bottle 

 after having been well shaken. How, then, shall we account for 

 this, unless upon the supposition that sea water from one part of 

 the world is, in the process of time, brought in contact and mixed 

 up with sea water from all other parts of the world ? Agents, 

 therefore, it would seem, are at work, which shake up the waters 



