160 



ATMOSPHERIC ELECTRICITY. 



the stratum in which the electrometer is placed, and E that of the stratum in 

 which the remote end of the conductor is placed, then, when the instrument 

 diverges with positive electricity, E — E', will be positive, and when it diverges 

 with negative electricity. E — E', will be negative. If the species of electricity 

 of either stratum be otherwise known, such an observation will indicate the 

 species of the other stratum ; but if not, it will only give a different result. 



ELECTRICITY OF THE AIR IN CLOUDED WEATHER. 



The electric state of the atmosphere in clear and unclouded weather only 

 has been hitherto explained. We shall now proceed to state the observations 

 which have been made when the heavens are more or less charged with clouds, 

 whether attended or not with rain, snow, hail, or other phenomena of storms. 



From the month of June, 1811, to May, 1812, both inclusive, M. Schubler 

 observed the electricity of the atmosphere in clouded weather and in times of 

 rain, hail, and snow. In the table on pp. 158, 159, a synopsis is given of the 

 results of his observations. An examination of the results registered in this 

 table will establish the following conclusions : — 



1. That in stormy weather, in rain, hail, or snow, the electricity of the^ air 

 is much more intense than at other times. 



2. That in such weather the electricity is sometimes positive and sometimes 

 negative, and nearly as often the one as the other. 



3. That in such weather the electricity often undergoes sudden changes 

 frorrr positive to negative, and vice versa. 



4. That in clouded weather, unattended by storms, rain, hail, or snow, the 

 free electricity of the air is positive. 



5. That the intensity of this electricity is greater in winter than in summer. 



