1865,] 



Atmospheric Electricity. 



15 



and where more than one observation was entered between these hours, that 

 which was nearest to 2 P.M. was alone reckoned. 



From these data, the monthly means of strength and variableness were 

 computed; but in neither case was any regularity exhibited. The only 

 results of this comparison which seem worthy of record are the annual 

 fine-weather means (derived from the monthly) for the prevailing directions 

 of wind. These are- 

 Calm. S.W. N. N.W. W. 



Strength 4'29 3'63 4'03 4'48 4*05 



Variableness.. 1-19 '88 1'22 171 '79 



I append, by way of specimen, the observations taken on June 29, July 1, 

 18, and 19. The first two days contain instances of some of the weakest 

 electricity that I have ever found in clear weather (I allude particularly to 

 the observations at 2 h 10 m June 29th, and at 3 h 47 m July 1st). The other 

 two days afford fair instances of observations during thunder and lightning*. 



. Aurora. 



b. Continuous rumbling of distant thunder in N.W., lasting till 5 P.M. 



* The details of daily observations from April 1, 1863, to February 28, 18G4, inclusive, 

 are given in a series of Tables which are preserved for reference in the Archives. 



