of Runt gen Rays in Transmission through Matter.. GG3 



Similar results were found when the beam was cut down by 

 nickel and copper, aluminium still being used as test-substance. 



When the beam was cut down by aluminium and tested 

 by aluminium, the absorption decreased slightly at first, but 

 more rapidly as successive sheets were placed in the primary 

 beam. 



Table IV. 



■ 

 ! Per cent, previously absorbed 

 by Al sheets. 



Per cent, subsequently absorbed 

 by Al (-00305). 







272 



30 7 



268 



07-5 



201 



88-0 



128 



If the beam was cut down by aluminium and tested by 

 nickel, the same apparent softening occurred. 



Table V. 



Per cent, previously absorbed 

 by Al sheets. 



Absorption by a Nickel sheet 

 (•00095 cm.). 



35 

 



457 

 55-4 

 47-0 



As this softening had not been observed when the charcoal 

 tube cooled by liquid air was used, it was again resorted to in 

 order to bring the bulb to the same stage of hardness. The 

 observations showed that the phenomena were similar but 

 not so pronounced. 



Discussion of Results. 



"When a primary beam passes through a thin sheet of an 

 element, there is a loss of energy (measured by the decrease 

 in the ionization it is able to produce in a given volume of 

 air) which may be due to : — 



1. A scattering of a portion of the incident energy : 



2. A transformation of energy into the production of. a 



homogeneous radiation characteristic of the element : 



3. A production of a corpuscular radiation accompanying 



both the scattered and the homogeneous radiation. 



