580 jS. J. Lloyd — Radium Content of Sea Water. 



Art. XL1. — The Radium Content of Water from the Gulf 

 of Mexico ; by Stewart J. Lloyd. 



The growing recognition of radium as an important factor 

 in geological processes* has led to a multiplication of analyses 

 of rocks and soils, of springs and of river waters for that ele- 

 ment. Our greatest reservoir of radium, the ocean, containing 

 at a minimum estimate one thousand tons of the metal, has 

 however received but little attention from investigators. It is 

 much to be desired that determinations of the radium content 

 of sea water from many different localities should be made, in 

 order that some definite knowledge may be acquired as to the 

 actual quantity contained in a unit volume, or if the content 

 varies from place to place or from time to time, that we may 

 learn definitely the extent of this variation and upon what it 

 depends. The present paper contains, in addition to a brief 

 statement of what has already been done in this field, the result 

 of an examination of the water of the Gulf of Mexico, an area 

 not hitherto covered. 



The radium content of sea water has so far been measured 

 by three scientists, Joly, Eve, and Satterly. The firstf made 

 determinations on waters from the Irish coast, from the North 

 and South Atlantic, the Mediterranean, the Black Sea, the Ara- 

 bian Sea, and the Indian Ocean, twenty-four in all. His 

 results varied from 38'0 X 10~ 12 grams radium per liter of 

 water to 4*0 X 10" 12 grams, with a mean of 17*0. Quantities 

 of water not exceeding 3,000 cc were taken, evaporated to half 

 the original bulk, acidified with hydrochloric acid and boiled 

 to drive off the emanation. Save that the quantity of material 

 used was rather small, and the percentage error correspond- 

 ingly large, no particular fault can be found with his method. 



Eve;): has measured on two separate occasions the amount of 

 radium in water from the North Atlantic. His first result 

 (1907) gave 0*3 X 10~ 12 grams radium per liter; the second 

 (1909), to which he attaches much more weight, gave 0*9 X 

 10~ 12 grams. 



Satterly§ examined in 1911 three waters from the coast of 

 England, obtaining an average value of 1*0 X 10" 12 . 



Through the kindness of Mr. Truman Smith of Mobile, Ala., 

 a sample of water from a point in the Gulf of Mexico about 

 two hundred miles due south of Mobile was obtained. Seven 



*T. C. Chamberlain, Jour. Geol., xix, 673. 



fPhil. Mag. 1908, xv, 385, 1908 ; ibid., xvi, 190, 1909 ; ibid., xviii, 396, 

 1909. Kadioactivity and Geology, page 46. 

 {Phil. Mag. xiii, 248, 1907 ; ibid., xviii, 102, 1909. 

 §Proc. Camb. Phil. Soc. xvi, 360, 1911. 



