582 S. J. Lloyd — Radium Content of Sea Water. 



and from the equatorial region of the Atlantic (38* X 10" 1 *) 

 would be of great interest. 



If we exclude Joly's results and the earlier one obtained by 

 Eve, we obtain as an average value for the radium content of 

 a liter of sea water, 1*2 X 10~ 12 grams. This would corre- 

 spond to a total amount of radium in the sea slightly exceeding 

 1400 tons.* As the amounts of radium found in river waters 

 are by no means sufficient to maintain this quantity of radium 

 in the ocean, we must postulate the presence in the latter of an 

 amount of uranium approximately sufficient to maintain the 

 radium at its present value. To do this, since one gram of 

 uranium is in equilibrium with 3*4 X 10" 7 grams of radium, 

 will require almost 4,200,000,000 tons of uranium, which may, 

 therefore, be taken as the amount of uranium contained in the 

 ocean. No attempt has so far been made to determine directly 

 the uranium content of sea water, though the result would be 

 of considerable interest. One hundred liters should contain, 

 if the above figures are correct, from three to five tenths of a 

 milligram of uranium, an amount of the same order of magni- 

 tude as that of gold in sea water, f 



Department of Chemistry, 

 University of Alabama. 



* Joly, Radioactivity and Geology, p. 48. 

 f Clarke, Data of Geochemistry, p. Ill, 1911. 



