[eve] on the amount OF RADIUM PRESENT IN SEA-WATER 33 



The high reading for number 3 may perhaps be due to the fact that 

 the HCl and distilled water were left for 6 days in the collecting 

 bottle. Number 6 was collected but a few miles from land. It 

 will be seen that my result agrees well with my previous value 0.6, 

 but it does not agree with the value 16 found by Professor Joly. I 

 publish this result, therefore, with some diffidence, but after taldng 

 every precaution in my power to eliminate error. At first sight it 

 may seem a matter of small importance whether there is 9 x 10~^^ 

 or 1.6 X 10^^^ gram of radium per gram of sea-water. That is not 

 the case. The amount of radium in the ocean affects the question 

 of the ionization of the atmosphere over the ocean with all the con- 

 sequent problems of cloud formation, atmospheric electricity and 

 propagation of electric waves by wireless telegraphy. It also enters 

 into the problem of penetrating radiation. Moreover, it has a direct 

 connection with the interesting results of Joly as to the amount of 

 radium present in deep sea deposits, and possibly with the amount 

 determined by Strutt in sedimentary rocks such as chalk or lime- 

 atone. 



A measurement was also made of the radium present in the 

 water of the River St. Lawrence. This water is supplied to the 

 City of Montreal without any filtration or treatment, and my sample 

 was taken from a tap in the Chemistr3/ Building. No great reliance 

 can, therefore, be placed in the result, 0.25. Joly found 4.2 for the 

 water of the River Nile. Thus we both found only four times as 

 much radium in the ocean as in the rivers named, although our rela- 

 tive values are as 17 to 1. This seems to show that the radium, 

 and presumably the accompanying uranium, find their way some- 

 what rapidly to the deposit on the bed of the ocean, for the ratio 

 of other salts in sea- and river-waters respectively show a vastly 

 greater ratio. Further measurements of the amount of radium in 

 river-water are needed, but the quantity is small and difficult to 

 measure. 



If we take the amount of radium in sea-water as 10~^^ gram 

 per gram of water, and in the soil as 4 x 10~^- a simple calculation 

 shows that the penetrating radiation from the soil should be about 

 1600 times as great as from the ocean, so far as the penetrating radia- 

 tion may be attributed to the presence of radium. 



If we follow a calculation of Becker^ we find the radium contents 

 of the ocean to be equivalent to the radium found in a very small 

 thickness of the deposits at the bottom of the ocean. 



* Terrestrial Magnetism, March, 1909. 



^ Bull. Geo!. Soc. of America 19, 113 (1908). 



Sec. III., 1!09. -.). 



