360 Mr Noda, Ionization of gases exposed simidtaneously to 



Experiment 5. 



Time in sec. 

 required by 



radium -rays 



Time in sec. 

 required by 



X-rays 



Time in sec. 

 required by 

 radium-rays 

 and X-rays 



Leakage due 

 to radium -rays 



Leakage due 

 to X-rays 





Leakage due 



to radium-rays 



and X-rays 



Eatio 



133-0 



107-9 



60-2 



0-00752 



000927 



0-0168 



0-0166 



0-99 



135-0 



117-3 



60-4 



741 



853 



159 



166 



1-05 



129-0 



119-9 



62-6 



775 



834 



161 



160 



0-99 



133-3 



107-9 



59-7 



752 



927 



168 



168 



1-00 



127-4 



94-3 



54-4 



785 



1065 



185 



184 



0-99 



127-7 



130-4 



65-0 



783 



767 



155 



154 



0-99 



126-5 



143-8 



66-7 



791 



695 



149 



150 



101 



130-4 



127-2 



66-4 



767 



787 



155 



151 



0-98 



131-5 



122-8 



66-2 



760 



815 



157 



151 



0-96 



134-4 



121-1 



63-7 



744 



827 



157 



157 



Meanl 

 valuej 



1-00 



1-00 



From this table we see that the ionization due to radium -ra} 7 s 

 and X-rays acting simultaneously is equal to the sum of the 

 ionizations due to their acting separately. 



§ 4. Secondly, I tried the combination of radium-rays and 

 uranium-rays. As the source of the latter I made use of uranium 

 oxide. The aluminium leaf at the bottom of the ionization vessel 

 was taken off and the hole was covered with a shallow circular 

 brass dish 7*5 cm. in diameter and 5 mm. in depth containing 

 uranium oxide, which was pressed against the bottom of the 

 cylinder by a strong spring. When only the radium was acting, 

 I put instead of this uranium dish another dish of exactly the 

 same form and size, but without uranium oxide, so that the 

 leakage by the radium took place in exactly the same conditions 

 whether it acted singly or conjointly with the uranium oxide. 



Since the radiations from the radium and uranium oxide can 

 be considered as constant during the experiment, I adopted in this 

 case a simpler procedure than in the previous one. The radium 

 specimen was put in the lead tube R and the leakage measured. 



Next, the uranium oxide dish was substituted for the empty 

 one and the leakage measured. Then the radium was taken off 

 and the leakage due to the uranium oxide only measured. 



The results are as follows. 



