120 



ROYAL SOCIETY OF CANADA 



It was also noted in these experiments that the conductivity of 

 the air in the cyHnder was less for corresponding barometric pressures 

 when the ground was frozen and covered with snow than when the 

 temperature was above freezing point and the ground bare. This is 

 shewn in Table IX which contains the mean readings for observations 

 taken under similar barometric conditions both with and without 

 snow on the ground. 



TABLE III 



Time 

 Nov. 25th, 1908 



Temp. 



No. of ions per c.c. per 

 sef. 



20 °C 



20. 5X 



20.2°C 



16.4 

 15.9 

 15.7 

 15.4 

 15.9 

 16.2 

 15.6 

 15.9 

 15.9 

 16.0 

 15.7 

 16.3 

 15.7 

 16.4 

 16.2 

 16.2 

 15.9 

 15.9 



Extreme Deviation 3%. 



