190 Mr Almy, On a Diminution of the Potential Difference, etc. 

 Table VII. Potential difference between the electrodes. 





Wire as cathode 



Wire as anode 



"Without magnet 



7400 

 2800 

 3000 



8400 

 <400 

 <400 



Magnet parallel to tube 

 Magnet normal to tube 



that of concentrating the discharge, so that the discharge through 

 the gas takes place by a sort of brush — or arc — discharge, in fact 

 with some similarity to disruptive discharge, instead of as usual 

 in the Crookes' tube discharge. And the effect of this concen- 

 tration is to very greatly increase the conductivity, or diminish 

 the resistance to discharge, of the tube. 



In conclusion, I wish to express my thanks to Professor 

 J. J. Thomson for the many privileges afforded at the Cavendish 

 Laboratory, and for his advice and help given in the course of 

 this work. 



