THE TRANSFORMATION OF ELEMENTS 241 



Coming to particular examples, Rayleigh, as has already been 

 stated, detected helium in the gases from the Bath waters, and 

 the amount is such that Dewar was able to employ them as a 

 source of helium. 



Moureu has examined the gases from over forty different hot 

 springs throughout France. In all cases rare gases were present 

 in quantities varying from 0-005 — 6*35 per cent. Of these argon 

 was detected spectroscopically in forty-three cases, helium in 

 thirty-nine. Usually the quantities were of the same order of 

 magnitude. No separation of the two was attempted. Moureu 

 states that his figures agree with the radioactivity of the springs 

 as determined by Curie and Laborde. The larger part of the 

 gases always consisted of nitrogen and carbon dioxide ; oxygen 

 was only present in small amount. The rare gases were pro- 

 portional to the nitrogen, inversely to the carbon dioxide. It is 

 hence at least possible that the argon detected by Moureu had, 

 like the nitrogen, originally an atmospheric origin. 



In later work Moureu has shown that traces of neon are 

 usually found. Since his methods were similar to those used by 

 Strutt, the remarks of the latter must be borne in mind re the 

 possibility of air-leakage accounting for small traces of neon. 

 Incidentally, Moureu and Biquard estimate that a spring at 

 Bourbon-Lancy produces over ten thousand litres of helium 

 annually, although this only amounts to 1*84 per cent, of the 

 total gas evolved. So that there is some ground for believing 

 that at any rate all the helium in the atmosphere is ultimately 

 derived from radioactive changes. 



Cady and McFarland have detected helium in forty samples 

 of natural gas from widely separated parts of America. They 

 observed neon in one instance. 



In view of the experiments of Ramsay and Cameron on the 

 production of lithium and other alkali metals from copper, 

 McCoy and Mile. Gleditsch have determined the amounts of 

 copper and lithium in several radioactive minerals. 



McCoy found that four uranium-radium minerals contained 

 both copper and lithium in easily recognisable amounts, while 

 a fifth, a sample of gummite, contained lithium, but no copper. 

 He considered that these results agreed with the possibility of 

 a transformation from copper to lithium. 



Mile. Gleditsch has examined a number of radioactive 

 minerals from different sources. They all contain lithium, but 



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