MR. GEORGE C. SIMPSON ON THE 



TABLE V. Dissipation. 



During the winter and spring the morning observations show a slightly higher 

 dissipation than the midday, while, on the contrary, during the summer and autumn 

 the midday values are the higher. For the whole year the dissipation is slightly 

 higher at midday than earlier in the morning, while the evening observations show 

 the lowest dissipation of the three. The value of the ratio q for nine months shows 

 a daily period, being lower at midday than at either the morning or evening 

 observations. The difficulties of observing during the winter three months make the 

 value of the ratio found then very doubtful. 



The evening fall in the dissipation no doubt stands in some relation to the evening 

 maximum of the potential gradient, while it is almost certain that the high evening 

 value of q is directly caused by the high value of the potential gradient at that 

 time. 



lonization. The results of the ionization observations are shown in Table VI. in 

 the same way as those of the dissipation were in Table V. 



