798 



Mr. J. Crosby Chapman on some 

 Table Y. 



Condition of experiment. 



Intensity of 



tertiary radiation 



reaching horizontal 



electroscope. 



Intensity of 

 tertiary radiation 

 reaching vertical 



electroscope. 



Direct secondary beam 



Secondary beam transmitted 

 through q uartz 



5-3 

 34 



1-3 



0-8 





Whence : — 



Polarization of direct secondary beam 



5 4 = 41. 

 1-3 



Polarization of secondary beam after 1 3*4 

 transmission through quartz J = : (j^g ~ 



4-2. 



Combining this with other results deduced in the same 

 way : — 



Table VI. 



Polarization of direct 

 secondary beam. 



Polarization of secondary 



beam after transmission 



through quartz. 



41 

 39 

 34 

 3-4 



4-2 



42 

 3-8 

 3-2 

 3-2 



3-8 



Mean value . 3*6 



3£ 



Again it will be seen that the polarization present in the 

 secondary beam is the same before and after transmission 

 through the quartz. That is, quartz which is active for 

 ordinary light has no power of rotating the plane of polariza- 

 tion of X-rays. 



Experiments on Sugar Solution. 



A solution of active sugar exerts a powerful rotation on the 

 plane of polarization of light. A similar experiment has 

 been made, using a beam of plane-polarized X-rays in the 

 place of the beam of ordinary light. 



