24 THE ROYAL SOCIETY OF CANADA 



V— Applied Field in volts. '^^^^^ ^ 



i — Current in e.s.u. per sq. cm. 

 k — Mobility = 3-35 x 10^ x i/V^ cm/sec. per volt/cm. 



If the linear portions of the curves be extended backwards, it 

 will be seen that they meet on the abscissae line at a current value, 

 io, of 1-98 X 10"^ e.s.u. If we assume that the mobilities are best 

 given by using the slope of the linear portions of the two curves, it 

 follows that the mobility formula should be modified to read 

 3271 d» (i-io) 



(2) K: 



9 V2 



cm/sec. per 300 volts/cm. 



In practical electromagnetic units, the mobility is therefore 

 givan by 



3200;: d^ (i-io) 



(3) K 



3 V^ 



cm. /sec. per volt/cm. 



where i and io are in e.s.u. and V in volts. 



