506 Mr Owen, On the Magnetic Deflexion of the Negative 



percentage of the discharge not stopped is nearly independent of 

 the magnitude of the discharge. This point will be discussed 

 later. 



Experiments were now made on a wire which had not been 

 previously heated. When a platinum wire is first heated there is, 

 as is well known, a very large initial leak which rapidly dies 

 away with the time. The mechanism of this initial leak was 

 investigated for this wire (Wire II.) and the results are given in 

 Table VI. As the wire was only heated for short intervals (only 

 a few seconds) the temperatures given are approximations only. 

 As will be seen the discharge diminishes so rapidly with the time 

 that in one case it appears to diminish as the temperature is 

 increased. The results are given in the order in which they were 

 taken. 



Table VI. (Wire II.). 



It will be seen from the above table that even for a wire 

 heated for the first time by far the greater proportion of the dis- 

 charge consists of corpuscles. There is, however, in the discharge 

 a good percentage (about 15 °/ ) of heavy particles which were 

 not deflected by the magnetic fields put on. 



It may be urged that this is due to there being dirt on the 

 wire which, when driven off by the heat, assists in carrying the 

 current. The following experiment, however, proves conclusively 



