Transformation Products of Radium. 



295 



ft particles expelled from it per second is then a measure of 

 the number of atoms of radium D which break up per second. 



Fia:. 2. 



/CO 











Sn 





















K 





















> 











h 























< 











'/n 





















— time, in Days 



Go 



8o 



Thus the activity of the successive product, when in equili- 

 brium with the parent substance, can be utilized to determine 

 the period of a substance which itself does not emit rays. 



For convenience, the physical and chemical properties of 

 the three radium products are tabulated below. It will be 

 shown in the next section that radium F is half transformed 

 in 1.43 days, It is probable that radium E emits y rays as 

 well as ft rays, but the intensity of the former in the experi- 

 ments has been too small to measure. 



Active deposit < 



of radium of -n -.• ,• 

 , , n ! Kadiations. 

 slow transtor- 



mation. 



Time to be half 

 transformed. 



Some physical and 



chemical properties of 



the product. 



Radium D 



Eadium E 



Radium F 



| 



no rays. 

 3 (and y ?). 



40 years. 



6 days. 



143 days. 



Soluble in strong acids, 

 not deposited on bismuth, 

 volatile below 1000 s C. 



Non-volatile at 1000° C, 

 soluble in acids, not de- 

 posited on bismuth. 



Volatile at 1000° C, 

 deposited on bismuth, 

 soluble in acids. 



