Possibility of sepai ating Isotope*. 53 1 



at height h , then their relative density at height /i + A/i is 

 given by J to ° 



Putting T = 220 as is approximately true in England, 



_ — p -5-38xlO- 3 Afc(M x -M«) 



Ah being measured in kilometres. If Mx — M 2 =2, therefore 



K _ -l-075xlO~ 2 AA 

 — 6 







It might be possible to design a balloon which would rise to 

 100,000 feet and there fill itself with air. In this case the 

 relative quantiiy of hypothetical metaneon would be reduced 

 from 10 per cent, to about 8'15, so that the atomic weight of 

 neon from this height should be 20'163 instead of 20*2. If 

 one could get air from 200,000 feet, e.g. by means of a long- 

 range gun firing vertically upwards, the atomic weight of the 

 neon should be 2012. Though the quantifies are measur- 

 able they do not appear sufficiently striking to warrant the 

 outlay and labour such experiments would entail. 



The second method which suggests itself for separating 

 isotopes by means of their different masses is to centrifuge 

 them. In this case the same equation holds as above except 

 that g varies from the centre to the edge. In a gas there- 

 fore 



dp_ Mr 2 dr_ _Mw 2 

 P ~ RT " 7 ~ RT ' 



whence P~Po e 2R1 \ 



v being the peripheral velocity. Here again, if K is the 

 ratio of the quantities present at the centre, the ratio at the 

 edge will be 



■&' 



K , 



-ST <*-**>, 



A peripheral velocity of 10 5 cm./s. or perhaps even 

 1*3 X 10 5 cm./s. might probably be attained in a specially 



