144 



Mr. M. Ishino on the Scattering and 



all directions. If absorption were negligible in comparison 

 with scattering, the effect in an external electroscope should 

 not be sensibly reduced by the interposition of an additional 

 thickness of meroury ; for it is obvious that 



scattering 



Fig, 5, 



without absorption should not lead to any diminution of 

 intensity of the rays. The electroscope was the same as 

 that used in the main experiments. The measurements 

 were carried out with and without mercury between A 

 and B. The ionization currents were as follows : — 



With mercury : 

 Without mercury 



12-97 div./min. 

 48-25 



The great decrease of the ionization current should be 

 mainly due to the absorption in the mercury. From the 

 observed values, the absorption coefficient was found to 

 be yLt = *64 cm. -1 . The value should be a little greater than 

 the true value, since the total amounts of the scattered rays 

 are themselves reduced by absorption. 



