92 



ROYAL SOCIETY OF CANADA 



meter needle commenced to move away from the stationary position as- 

 sumed under the influence of the volta effect, when a pressure of ap- 

 proximately 8 cms. of mercury was reached, and the direction of dis- 

 placement was such as to correspond to the acquisition of a positive 

 charge. The sign of the charge acquired, it will be seen, fitted in then 

 with what was to be expected from the absorption of the rays. For the 

 higher pressures the rate of motion of the needle as it moved to take up 



i. ■.' 



mm^mmfm^TT'Tm 



'f^T3WW^ 



■:i Atii^='j;;^^fm 



A 





K>n4;:.:|:x:l:;::lns|::i|:: .l; -|:;-:t:--H^:nr!:;|rin;"!|-::;i;~i:i..r--Tl:iH-! 



Fig. v." 



_Jia 



TABLE III. 



the deflection corresponding to a selected pressure was slow, and on this 

 account the second line of procedure mentioned above was followed. In 

 taking the observations the pressure was reduced as low as possible and 

 then the rate of motion of the needle noted as it moved out to take up 

 the equilibrium position. 



Examples of these movements of the needle are given in the num- 

 bers recorded in T/bles III and IV, and in the curves drawn from them 

 and shown in îigs. V and VI. In the one case the movement corre- 



