226 OF ELECTRICITY. CHAP. 7- 6. 



During very clear weather, the air has 

 generally been found to have a positive 

 Electricity, and the exceptions to this rule 

 have generally happened when either a strong 

 Wind has blown, or when there have been 

 clouds in the vicinity of the electrometer. That 

 large electrified clouds throw the surrounding 

 air into an opposite state, has already been 

 stated ; and some circumstances have induced an 

 opinion, that there are alternate portions of air 

 with different Electricities round the electrified 

 clouds. And it becomes a question for future 

 solution, whether, when air is found electrified 

 positively, there be not a counter charge some- 

 where else ? Possibly the whole Atmosphere, 

 and the Earth too, may have electric polarity. 

 That the electric state of the atmosphere varies 

 much at different times, is beyond a question, 

 from the facts above stated ; but the causes of 

 its irregularities, which, in fact, involves the 

 causes of clouds, &c. is as yet a mystery. There 

 have been found alternations in the electric state 

 of the atmosphere, that is, rapid changes from 

 a positive to a negative state, and vice versa. 

 These circumstances were observed near the 

 Appennines, when a strong Wind blew, and 

 when clouds . hung about the tops of those 



