400 2 >. Eafon on the AJcent of Vapour. 
From this it follows: If two clouds are elec- 
trifled by the lame power, they will repel each 
other, and the vapour be fufpended in both; 
but, when one is pofltive and the other negative* 
they will attraCl each other, and reftore an equi¬ 
librium. The electric power, by which the 
vapour was fufpended, being now deftroyed 
by the mutual action of the clouds on each other, 
the particles of water will have an opportunity of 
running together into each other, and, as they 
augment in fize, will gain a greater degree of 
gravity, defeending in fmall rain, or a heavy 
Ihower, according to circumftances. 
A cloud, highly eleClrified, pafling over a 
high building or mountain, may be attracted by, 
and be deprived of its electricity, without or 
with a violent exploflon of thunder. If the cloud 
is electrified plus, the fire will defeend from the 
cloud to the mountain ; but, if it be electrified 
minus, the fire will afeend from the mountain to 
the cloud. In both cafes, the effeCt is the fame* 
and generally, heavy rain immediately, or foori 
after, follows: this is v/ell known to the inha¬ 
bitants of, and travellers among, mountains. 
From this, we can eafily account, why thunder-* 
Ihowers are often partial, falling near, or among 
mountains, and the rain in fuch quantities, as 
to occafion rivers to be overflowed; whilft, at 
the diftance of a few miles, the ground continues 
parched 
