[cline] 



RADIATION AT THE SURFACE OF THE EARTH 



115 



In the course of his experiments at Toronto, C. S. Wright on 

 several occasions made observations on the conductivity of air en- 

 closed in metallic receivers over periods of time extending in some 

 cases up to six or seven hours. Two typical sets of such observations 

 are given in the following table : — 



TABLE II 



Time 



Qq — number of ions per c.c. per sec 

 reduced to 0°C. 



and from the readings recorded in this table it will be seen that there 

 is no evidence of any appreciable regular variation in conductivity, 

 and it is to be noted also that the extreme values obtained for the 

 conductivity did not differ from the mean by more than 3% of the 

 latter. 



