472 ROLLIN D. SALISBURY 



bonate is about 20 times as abundant as sodium chloride in river 

 water, but only -^-5 a s abundant in sea water. If the calcium car- 

 bonate which has been taken to the sea in solution by rivers had 

 remained in solution as calcium carbonate in the same proportion 

 that the sodium chloride has remained in the sea water, the figures 

 representing the amount of common salt which the sea contains would 

 seem almost insignificant in comparison. Even if calcium carbonate 

 is changed to calcium sulphate in the sea, as is sometimes thought, 

 the case is not seriously altered, for the amount of calcium sulphate 

 in the sea is but a small fraction of the amount of sodium chloride. 

 In order that the sodium chloride should have attained such pre- 

 dominance, it is necessary to suppose that enormous quantities of 

 the compounds of calcium have been extracted, if the salt of the 

 sea has been derived from the land. 



The average river water contains about seven times as much 

 magnesium carbonate as sodium chloride, four and a half times as 

 much silica, twice as much calcium sulphate, twice as much sodium 

 sulphate, more potassium sulphate, and more sodium nitrate; yet 

 the combined volume of all these substances in the sea water is but a 

 small fraction of the amount of sodium chloride. 



By either of these lines [(1) and (2)] of approach, we reach the 

 conclusion that the amount of mineral matter which the sea has lost 

 from solution far exceeds that which it has held until the present 

 time. 



TABLE I 



Amount of Mineral Matter in Solution in One Cubic Mile of Sea Water 1 



Constituents Tons 



Chloride of sodium (NaCl) ----- 117,434,000 



Chloride of magnesium (MgCL) - - - 16,428,000 



Sulphate of magnesium (MgS0 4 ) - 7,154,000 



Sulphate of calcium (CaS0 4 ) - 5,437,000 



Sulphate of potassium (K 2 S0 4 ) - • '-■ ■ - 3,723,000 



Bromide of magnesium (MgBr 2 ) - - - 328,000 



Carbonate of calcium (CaC0 3 ) ... - 521,000 



For sea water, total dissolved matter - - 151,025,000 



1 Dittmar, Challenger Reports, Physics and Chemistry, Vol. I, p. 204. 



