﻿The Growth of Radium C jrom Radium B. 293 



Curve B relates to the case in which RaC 2 alone emits 

 /3 rays and is calculated from the formula 



C 2 = XB^dB J : 



\„t 



■\,t 



+ 



L(Ac! — A, B ) (A.c_> — \b) (Vb _ ^Ci)(^c 2 "" ^cj 



+ 7 



(X B — Xc 2 )(Xc 



-Xo 2 )J- 













Fig. 



1. 











100 

 80 



60 



'in 















































O/? 





































20 





// 







































/Pf/A/UT£S-. 



The values taken in these equations are the foil 

 \ B =4-33xlO- 4 sec." 1 



owing 



\ Ci = 5-93xlO- 4 „ 

 Xc 2 =8-3 xlO- 3 „ 



corresponding to the half-value periods of 26*7 and 19*5 and 

 1*4 mins. respectively. 



It will be seen that the two curves obtained from (1) and 

 (2) respectively differ appreciably from each other, and it is 

 clear that if both RaC^ and RaC 2 contribute to the radiation, 

 a curve will be obtained lying between the curves A and B. 

 It was therefore hoped by this method to find out whether 

 RaC 2 contributes an appreciable share of the j3 radiation 

 from RaO. The curves are so drawn that the maximum 

 which occurs after 32*8 minutes is 100. 



To carry out an experiment a plate was exposed in the 

 usual manner in an electric field to radium emanation for a 

 few minutes so as to collect on its surface a deposit of RaA, 

 After removing the plate from the emanation, a second 



