﻿872 Dr. E. N. da C. Andrade on the Carriers of 



calculation. Hence the vertical rise in the air will be still 

 smaller.) The rise in the air can be neglected, as being not 

 more than 7 per cent, of the total rise : our other measure- 

 ments do not allow an assumption of greater accuracy. The 

 whole vertical rise may, therefore, for purposes of calcula- 

 tion be assumed to take place in the flame. 



For example, if we take the case for which the distribution 

 curve is a, fig. 2, the whole vertical rise 



= 0-95 cm. = -^ (360 + 26) 



where w = velocity of carrier in unit field in flame, 



F = strength of field in flame =150 



° cm. 



/field in air = 1100 — \ 

 \ cm. / 



and of the term in the bracket the first, 860, is proportional 

 to the vertical rise in the flame, and the second, 26, to that 

 in the hot air, which, as will be seen, is negligible. 



Hence <o = ., r( ,° L u ,, n ~ =2'7— - / - 



150 x 0'9o sec./ cm 



386 nn cm. /volt 



olt 



The other curve in fig. 2 gives for co 2*5 — - / ; while 



° fc sec./ cm. 



two careful experiments without the screen give 2*4 and 



2'6 / . Hence we may take the velocity of migration 



sec./ cm. J " ° 



of the positive carriers of the second kind in the flame to be 



. , _ _ cm. /volt 



approximately 2'D / . 



1 r " sec./ cm. 



§ 4. Calculation of the Velocity without an Air-path. 



An experiment made to see if the metallic current was 

 markedly lessened by making the carriers pass through a 

 greater distance in the flame (i. e. if many carriers were 

 permanently neutralized) enables us to estimate roughly the 

 velocity of the carriers without making any assumptions as 

 to what takes place in the air-gap, The curves in fig. 3 show 

 the resultant deflexions for the two cases : 



(1) in which the carriers pass through about 0*5 cm. 



in the flame ; 



(2) in which the carriers pass through 1*4 cm. in the 



flame. 



