292 



Mr. E. H. Nichols on the Diurnal 



eclipse day variation is, however, unsmoothed. There is a 

 considerable decrease in conductivity and electric charges 

 from 10 a.m. to 5 p.m., commencing- soon after the primary 

 phase of the eclipse. The maximum for the day, instead of 

 appearing in the early afternoon, is retarded till about 5 p.m. 

 There is a decrease in the mobility which might be explained 

 by the fact that increased relative humidity due to the fall 

 in temperature during the eclipse causes condensation of 



Fig. 3. — Eshdalemuir , 1914 (continued). 



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August mean diurnal variation (smoothed) - 

 Eclipse day variation (unsmoothed). _ 



water molecules on the ions. There is but little indication 

 of an increase in the ratio of the electric charges, which has 

 been found by some observers, during or near the totality 

 stnge, and ascribed to the reduction in the number of the 

 negative ions *. 



Superficial observation might connect the depression in 

 the electrical quantities from 10 a.m. to 1 P.M. with the 

 eclipse, but a similar depression is obtained in the August 

 * Leyst, Luftelektrischen Beohachtungen, 1907. 



