Prof. Owens on Thorium Radiation. 

 Table X a. 



Uranium Oxide. Thick layer. 

 Conduction -current with Pressure. 

 Plates 2 mm. apart. Lower plate 95 volts -f 



383 



Pressure. 



Time of 1 00 div. in sec. 



Current. 





15 



910 



1000 





20 



73-4 



1220 





25 



66-4 



135 





30 



61-0 



1480 





35 



57 



159-0 





45 



53-4 



168-0 





55 



51-4 



175-0 



Table X b. 



Uranium Oxide. Thick layer. 

 Conduction-current with Pressure. 

 Plates 6 mm. apart. Lower plate 95 volts + 



Pressure. 



Time of 100 div. in sec. 



Current. 



15 



600 



100-0 



20 



51-4 



1160 



25 



48-2 



1240 



30 



476 



126-0 



35 



48-8 



1230 



45 



53-4 



1120 



55 



60-4 



99-3 



8. Absorption of Radiations in Air. — The absorption of 

 uranium radiation in different gases under various conditions 

 has been studied by Rutherford *. Using thin layers of 

 the active material, so that the radiation was approximately 

 homogeneous, he found that for different gases at a given 

 pressure the absorption followed the order of the gas densities, 

 and for a particular gas the absorption was proportional to 

 the pressure. 



* Phil. Mag. Jan. 1899. 



