|28 ATMOSPHERIC ELECTRICITY. 



It is alway* 7* The electricity that takes place when the werrtlW 



positive at the d enrs up j s a i ways positive. When the air takes up moisture 



clearing up of , , 



the weather, very rapidly the intensity of the electric state of the wire, as 



and more well as its quickness in becoming again sensible when destroyed 



rapidly pro- . , , , 



•luced as the are great j but the latter diminishes as the weather becomes dryer. 



evap U more It sometimes happens that the electricity thus caused continues 

 a long time in its state of intensity, and begins afresh after 

 being interrupted. Beccaria thinks these effects are owing to 

 electricity being brought from great distances by the wind. 

 Particular 8. If the sky becomes clouded over the place of observa*- 



observations of tion> and only an high cloud is formed without any secondary 

 figures' and clouds under it, and the cloud itself be not part of a cloud that 

 changes, and drops rain elsewhere, then the electricity of the wire is either 

 taut electricity. P os ^ ve or nu ll. But if the clouds resemble locks of wool 

 moving to and from each other j or if the general eloud is 

 forming very high and is stretched downwards like descending 

 smoke, then a frequent positive electricity commonly takes 

 place, which is more or less strong in proportion to the quickness 

 wilh which the cloud is forming, and foretels the quantity and 

 suddenness of the rain or snow which follows. 2. When a 

 rare, even, and extensive cloud is forming, which darkens the 

 colour of the sky, and renders it grey, positive electricity, very 

 intense and speedily recovering its intensity when taken off, is 

 produced j which state diminishes and even fails as the gathering 

 of the cloud slackens j but on the contrary, if the cloud con- 

 tiuues to increase gradually by the accession of smaller clouds, 

 resembling locks of wool which are continually joining and 

 Fogs give separating, the positive electricity usually continues. 3. Low 



" and thick fogs (especially when they rise into a superior air con- 

 siderably free from moisture) carry up to the wire electricity 

 which gives frequent small sparks, and the balls diverge between 

 20' aud 30°. If the fog seems stationary and continues to 

 environ the wire, the electric signs soon disappear j if it con- 

 tinues to rise and another cloud of fog succeeds, the wire is again 

 Rockets made electrified, though less than before. Sky rockets sent through 

 Ma otf suc h thick low and continued fogs have often afforded our 



celebrated observer signs of electricity by means of a string, 

 affixed to them. He never* however, observed in any of the 

 above circumstances, any signs of negative electricity except 

 once by a sky rocket sent through a fog, in which he saw the 



star 



