182 Mr Wilson, On the Magnetic Deflection of Cathode Rays. 



Metal forming 

 Cathode 



Atomic 

 weight 



Deflection 

 (d) 



Spark 

 length 



Potential 



Difference 



(V) 



djV 



Aluminium 



27 



mms. 

 23 



mms. 

 2-0 



28-0 



122 



Iron 



56 



20 



2-5 



33-4 



116 



Copper 



63-6 



18 



3-0 



39-0 



113 



Zinc 



65 



16-6 



4-5 



54-2 



122 





108 



10 

 18 



11-0 



3-0 



110 

 39-0 



105 

 113 



Silver 



Tin 



118 



17 



3-6 



45-3 



114 



Platinum 



195 



16 



4-0 



49-3 



112 





207 



16 

 11 

 18 



4-0 



10-0 



3-0 



49-3 



1050 



39-0 



112 

 113 

 113 





Lead 







15 



5-0 



59-0 

 Mear 



115 





...114-2 





The P. D.'s corresponding to the spark lengths are taken from 

 Paschen's tables ( Wied. Ann. 37, p. 79, J 889) for sparks between 

 spheres of 1 cm. radius. 



These results show clearly that d V V is nearly a constant 

 quantity whatever the metal of which the cathode is composed 

 and potential difference used to produce the discharge. The 

 variations from the mean value are not greater than can be readily 



accounted for by experimental errors. It thus appears that — is 



the same for the cathode rays proceeding from each of the eight 

 metals tried. 



These experiments were carried out at the Cavendish Labora- 

 tory and my best thanks are due to Prof. Thomson for advice 

 during the course of the work. 



