﻿Electricity in Flames containing Metallic Vapours. 



873 



The bead was moved horizontally from one position to the 

 other without altering the relative positions of the flame and 

 the electrode. It will be observed that the metallic currents 

 are very much less for all positions of the strip in the case when 



Fiff. 3. 



Current *— >■ 



the carriers pass through the extra centimetre in the flame, 

 but further, that the maximum is reached at a lower position 

 in the case where the path in the flame is short. If we 

 assume that the vertical distance between the points at 

 which the maxima begin in the two cases (065 em.) is the 

 vertical rise taking place in the 0*9 cm. of flame between 

 the two positions, we can calculate the mobility. The 



potential gradient in the flame being 220 



cm. 



0-9 x 300 



1-8 



cm 



sec 



. /volt 

 ./cm. * 



230x065 



This is in as good agreement as we can expect with our 

 previous values. 



§ 5. Action of Glowing Platinum on Metallic Vapours. 



It was also attempted to measure the velocity of the 

 carriers without making them pass through air by bringing 

 the earthed electrode into the flame itself. For this purpose 

 the brass plate electrode was replaced by a very fine platinum 

 net, fixed in the flame : an insulated platinum strip was so 

 arranged that it could be moved in the flame vertically and 

 close to the net. When, however, the net was earthed, and 

 the strip connected to earth through a galvanometer, a 



galvanometer. 



