ADAMS. — TRANSMISSION OF RUNTGEN RAYS. 



689 



0.0012 cm. When the first screen was of silver, however, and the 

 screen for which the penetrating power was being investigated was 

 of aluminium, the data in Table VlII were obtained. According to 



TABLE IX. 



Effect of Transmission tiirocgii Aluminium on Penetrating 



Power for Silver. 



these measurements, the effect of transmission through silver on ab- 

 sorption by aluminium is very small. A slight modification of this 

 experiment, performed some days later, gave a more striking result, 

 as shown in Table IX. " Ag.-Al. Screen " indicates that the rays trav- 



VOL. XLII. 44 



