from an Arc and from Incandescent Metals. 257 



As in air, the gas from the hot wire can discharge negative 

 electricity before it can discharge positive, while at very high 

 temperatures the rate of discharge is the same approximately for 

 positive and negative. With C0 2 again it is always observed that 

 the discharge of negative electricity begins just as soon as the 

 wire becomes luminous. 



(28) The velocity of the carriers was measured for various 

 temperatures of the wire as in the previous cases, and the same 

 results obtained, the velocity diminishing as the temperature of 

 the wire w T as raised. In one series of experiments numbers ranging 

 from '03 cms. per second to "006 cms. per second, for a force of one 

 volt per cm., were found. 



The velocity of the negative carrier is again greater than that 

 of the positive ; one experiment gave a difference of 25 °/ . 



Further experiments, both with the arc and with the incan- 

 descent wire, are being carried on, and it is hoped to publish 

 further results soon. In the meantime it is better to postpone any 

 further discussion of the results in this paper. 



I wish in conclusion to thank Prof. Thomson for many valuable 

 suggestions. 



