﻿634 



Dr. G. von Hevesy 



the 



Several of the curves obtained for radium, thorium, and 

 actinium products, typical of a great number (over 100), are 

 shown in figs. 1, 2, and 3. 



Fi>r. 1. 



fid 3+ fid C. 



Z»/Z* £#4 



1 



(I 



GJ/CJSO4 



Ph/Pb(c 2 H 3 z \ 

 Cu/Cu SO4 



/& J5 Z0 25 



Mm 



From the variation of the activities in the series of curves 

 given, it is not difficult to deduce the relative amounts of 

 B and C products which have been deposited. For example, 

 to one who is acquainted with the nature of the decay-curves, 

 it is obvious that the two upper curves of fig. 1 show at 

 once that radium B is in excess of the equilibrium amount, 

 and that the four lower ones indicate that B is present in 

 less than equilibrium amount. 



The curves corresponding to any one potential are capable 

 of being repeated with great exactness, except in the case 

 of magnesium, which gives inconstant results owing to the 

 evolution of hydrogen at its surface. In the figure the 

 steepest rise-curve obtained is given. 



