1912] CLARKE— SOME GEOCHEMICAL STATISTICS. 225 



weight. For the volume of the ocean there are several estimates. 

 In my former calculations it was taken as 302,000,000 of cubic miles, 

 while Murray found a larger figure, 323,722,150 cubic miles. These 

 values, however, are now supplanted by later and more definite 

 estimates, as follows : According to Karstens,'' the volume of the 

 ocean is 1,285,935,211 cubic kilometers, or 308,509,000 cubic miles. 

 KriimmeV still later, estimates the volume as 1,329,945,870 cubic 

 kilometers, or 319,087,500 cubic miles. From these figures, with 

 density 1.026, the mass of the ocean is as follows: 



Karstens, 1,319,369,526,436,000,000 metric tons. 



Kriimmel, 1,364,524,469,802,000^000 metric tons. 

 The saline matter, 3.5 per cent., is therefore : . 



Karstens, 46,178 X 10^- metric tons. 



Kriimmel, 47,758 X 10^- metric tons. 

 Puting the specific gravity of the oceanic salts at 2.25, their volume 

 is easily found by the subjoined equation: 



3.5 FX 1.026 

 100 X 2.25 ' 



in which V represents the volume of the ocean. The value of x 

 then is. 



With Karstens' volume 4,923,800 cubic miles. 



With Kriimmel's volume 5,092,600 cubic miles. 

 The second of these values, derived from Kriimmel's estimate of the 

 volume of the ocean, represents a quantity of saline matter which 

 would cover the entire surface of the earth, 197,000,000 square 

 miles, with a layer 136.5 feet deep, or 468 feet over the land area 

 alone. Figures like these show that the salts enclosed in the rocky 

 crust of the earth are, in amount, relatively insignificant. 



From Dittmar's analyses of sea water, made for the reports of. 

 the Challenger Expedition, the mass of each radicle contained in the 

 oceanic salts can be calculated. In the following table I give Ditt- 

 mar's percentage composition of the salts, and in a second column 

 the weights corresponding to the total mass of 47,758 X 10^^ metric 

 tons as found from Kriimmel's figure the volume of the ocean. 



' Inaugural Dissertation, Kiel, 1894. 

 ^"Encyclopedia Britannica, nth ed., Vol. 19, p. 974. 



