>raS: NAttTRAl ttlStORT 0t CLOtJDS. ^1 



(wheFe, it appears, the rapid union of the |?articles into 

 drops is accomplished,) to a vast height and extent in the 

 superior atmosphere. The conducting line, therefore, may 

 be considered as prolonged from the top of the column to 

 the very extremity of each of these fine fibres of cloud, 

 which are often extended, in all directions, as correctly as 

 those of a lock of hair insulated on a charged conductor. 

 The intention in this case seems to be not so much the pre- 

 cipitation <if water, as that of the electric fluid which keeps 

 it |n suspension. This purpose accomplished, (and the 

 reader may conceive how great a discharge must be effected 

 by a number of such machines acting at once on a small 

 tract of country,) the water unites into larger drops through 

 the whole extent of the atmosphere; it subsides in a con- 

 tinuous sheet, under which the condensed product of the 

 superficial evaporation moves along, in the form denomi- 

 nated scud; and the rain comes down freely and generally. Seal. 

 until the atmosphere is disburdened, or until the partial 

 vacuum which is formed brings in a drier air from the north- 

 ward. 



Negative, as well as nonelectric rain (which sometimes Negatite xn 

 falls, though strong positive and negative signs precede or ^^ 

 follow it in the clear air) must necessarily result from the / 

 action of a central mass of cloud, in which a strong positive 

 charge exists, on the clouds of less extent which fall in its 

 way ; and it is to be considered also, that rain, at the eleva- 

 tion in which it is formed, may be perfectly nonelectric, 

 (i. e, it may result from the union of clouds differing in 

 electricity, and hence uniting in rain,) yet at the moment 6f 

 arriving at the Earth it may differ so much in its charge 

 from the atmosphere below, the only standard of comparison, 

 •^8 to be strongly negative or positive with respect to the 

 latter. But these considerations belong mOre properly to 

 the subject of atmospheric electricity. 



We shall conclude with a brief review of the modifications. Review of th\t 

 ascending from the stratus, formed by the condensation ©f '^^^'^"^^'^^ 

 vapour, on its escape from the surface, to the cumulus, col- 

 lecting the water arrested in the second stage of the ascent; 

 both probably subsisting by virtue of a positive electricity. 

 From these proceeding, through the partially conducting 



cumr.lo- 



