12 Prof. Everett Observations of [Jan. 12, 



ning, during which frequent observations were taken, showing very strong 

 electricity, generally negative. 



No more instances occurred till the evening of February 26th, when hail 

 fell, with short intermissions, from a little before 9 h 30 m P.M. till after mid- 

 night, accompanied by much lightning and some thunder. The only obser- 

 vation of the electrometer was at 9' 1 30 m , when strong positive sparks were 

 obtained. 



It appears from these instances, that thunder-storms in the neighbour- 

 hood of the place of observation are accompanied by extremely strong 

 indications of atmospheric electricity, but that neither silent lightning nor 

 the distant rumbling of thunder is accompanied by any marked effect on 

 the electrometer. 



For the sake of comparison with numerical data given in the former 

 paper, applying to the six months October 1862 to March 1863, I subjoin 

 the corresponding data for April to September 1863, thus completing a 

 year from the commencement of observations. 



Positive only. Negative only. Both kinds. 



Days. Days. Days. 



Rain .................. 17 7 12 



Snow .................. 1 2 



Hail .................. 1 1 



Fog .................. 3 



Thunder or lightning ---- 2 2 3 



There were 34 days on which both positive and negative electricity were 

 observed ; and on 29 of these, rain or other downfall occurred. The 

 remaining 5 days, with the strongest negative observed, and the state of 

 cloud and wind at the time, were as under (the scale for cloud being 0-10, 

 and for wind 0-6). 



It will be observed that in all these instances the weather was cloudy 

 and the negative electricity weak, characteristics which also belong to the 

 corresponding instances* in the former paper. The remark there made, 

 that on every day on which negative electricity had been observed, positive 

 had also been observed, holds good down to the present date (March 1864). 



The monthly means of the results of fine- weather observations, for dif- 

 ferent hours of the day, from April to September 1863, are shown in the 

 following Table. They have been computed in the same manner as the 

 corresponding numbers in the former paper. 



