﻿Disintegration of Elements by « Particles. 



425 



experiments. The ordinates represent the number o£ scintil- 

 lations observed per minute per milligram of activity of radium 

 C, measured by 7 rays ; the abscissae, the stopping power 

 for a. rays of the absorbing screens, expressed in terms of 

 centimetres of air. The dotted curve A gives the natural 

 effect observed when the screen of paracyanogen was absent 

 or replaced by a film of paraffin wax ; the full curve B the 

 effect when present. The difference of these curves there- 

 fore represents the effect due to the nitrogen in the para- 

 cyanogen. It will be seen that the maximum range of the 



Fig-. 3. 



20 



1-5 



0-5 



\ 





Forward and Ba 

 from Afitt 



cAward Particles 

 ■oyen. 









\ 















~-JV 



\B 









\cC 









■ -»» 



% 









:0 25 30 



A bsorption m cms of sir 



40 



backward particles from nitrogen is about 18 cm. Curve C 

 is the absorption curve for the particles emitted by nitrogen 

 in the forward direction. 



In the following table are given the maximum ranges of 

 the particles liberated from the elements which show the 

 disintegration effect, for both forward and backward 

 directions. 



Element. 



Forward rang* 



Boron 58 



Nitrogen 40 



Fluorine 65 



Sodium 58 



Aluminium 90 



Phosphorus ••• 65 



Backward range. 

 cm. 



38 

 18 

 48 

 36 

 67 

 49 



