﻿636 



Dr. G. von Hevesv on the 



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£ 66 



£3 



■JQO 



In this vv'ork the period of thorium C has been taken, not 

 as 55 minutes, as is usually done, but in accordance with 

 v. Lerch's measurements (Joe. cit.) as 60'5 minutes. 



The curves obtained, and the results deduced from them, 

 show that the three B products appear to be identical in their 

 electrochemical behaviour, and the three C products also. 



Figs. 4 and 5 show the relationship between the per- 

 centage of C and B respectively of the total amount deposited 

 on the electrode, and the potential required to bring about 

 deposition. 



Fig. 4. 



+4$ +0-3 +0-J ~M -J-3 



■0S -0-7 -0-9 -/•/ 



Volts. (e Hg ). 



■/■S -/-S -J-7 -J9 



" Percentage " means the percentage of the equilibrium 

 amounts, 50 per cent, representing a deposit of B and C in 

 amount corresponding to radioactive equilibrium. 



The potentials, of course, are measured against the calomel 

 electrode. It is seen that the curves in all three cases 

 are remarkably analogous. It would be natural to expect 

 that very pure C could be obtained with the potentials 

 Au/ILAuC 1 l 6 or Pt/H 2 PtCl 6 . This is, however, not so, for in 

 these cases sold acts like a metal lying between silver and 



JSQ 



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.66 



.40 



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