74 



MR. GEORGE C. SIMPSON ON THE 



results of my observations of the dissipation tabulated according to the potential 



gradient. 



TABLE VII Potential Gradient and Dissipation. 





It will be seen that here also there is the same marked relation between the 

 potential gradient and the dissipation; but the relation between the potential 

 gradient and the value of the ratio q does not appear so clearly. Nevertheless, the 

 table does not disprove that the ratio rises with the potential gradient, there is 

 rather some support given. In the first place there is a distinct rise in the ratio 

 over the range from 50 to 200 volts/metre, and the highest value found falls between 

 300 and 400 volts/metre. When the whole year is taken into account there are only 

 two out of the six divisions which do not conform to the rule. 



Potential Gradient and lonization. So far no results have been published 

 showing the relation between potential gradient and ionization, so that the results 

 given in the following table cannot be compared with previous work. 



TABLE VIII. Potential Gradient and lonization. 



The first striking fact which this table shows is the great dependence of the 

 potential gradient on the ionization ; this we might have expected from the 

 dissipation results already considered. 



* These small numbers in brackets give the number of observations from which the mean is drawn. 



