266 THE PHYSICAL GEOGRAPHY OF THE SEA. 



Cubic miles of sea Originally washed down into it by the rivers and 

 ^^^^- the rains ever take the trouble to compute the quan- 



tity of solid matter that the sea holds in solution as salts ? Tak- 

 ing the average depth of the ocean at three miles, and its average 

 saltness at 8^ per cent., it appears that there is salt enough in the 

 sea to cover to the thickness of one mile an area of ten millions 

 of square miles. These ten millions of cubic miles of crystal 

 salt have not made the sea any fuller. All this solid matter has 

 been received into the interstices of sea water without swelling 

 the mass ; for chemists tell us that water is not increased in vol- 

 ume by the salt it dissolves. Here we have therefore displayed 

 before us an economy of space calculated to surprise even the 

 learned author himself of the "Plurality of Worlds." 



496. There has been another question raised which bears upon 

 The saltness of water ^hat has already been said concerning the ofidces 

 retards evaporation. Tf^iiic]^^ in thc sublimc systcm of tcrrcstrial arrange- 

 ments, have been assigned to the salts of the sea. On the 20th of 

 January, 1855, Professor Chapman, of the University College, To- 

 ronto, communicated to the Canadian Institute a paper on the 

 " Object of the Salt Condition of the Sea," which, he maintains, is 

 ''^mainly intended to regulate evaporation^ To establish this hy- 

 pothesis, he shows by a simple but carefully conducted set of ex- 

 periments that, the Salter the water, the slower the evaporation 

 from it ; and that the evaporation which takes place in 24 hours 

 from water about as salt as the average of sea water is 0.54 per 

 cent, less in quantity than from fresh water. "This suggestion 

 and these experiments give additional interest to our investiga- 

 tions into the manifold and marvelous ofiices which, in the econo- 

 my of our planet, have been assigned by the Creator to the salts 

 of the sea. It is difiicult to say what, in the Divine arrangement, 

 was the main object of making the sea salt and not fresh. Wheth- 

 er it was to assist in the regulation of climates, or in the circula- 

 tion of the ocean, or in re-adapting the earth for new conditions 

 by transferring solid portions of its crust from one part to anoth- 

 er, and giving employment to the corallines and insects of the sea 

 in collecting this solid matter into new forms, and presenting it 

 under different climates and conditions; or whether the main ob- 

 ject was, as the distinguished professor suggests, to regulate evap- 

 oration, it is not necessary now or here to discuss. I think we 



