[ ]' 
a cloud is filled with lightning, which is the fame as^ 
the eledric matter, the watery particles, like other 
eledrified bodies, will repel each other, but being 
fuddenly deprived of this repelling matter, will by 
their mutual attradion come together again with 
fome velocity, and, therefore, will run into drops 
larger than ufual. 
When the wind blows from the fouth, it isgene= 
rally warm, and comes replete with aqueous va- 
pours, which it has dilToived j but coming into a colder 
climate, it cannot there keep the fame quantity of> 
vapours diflblved that it did before, and confequently 
niufi: part with fome of them, and let them preci- 
pitate j and, therefore, loutherly winds generally 
bring us rain. On the other hand, when the wind 
blows from^ the north, or any point near it, as it is 
very cold, it cannot have difiblved a great deal of 
aqueous vapours where it came from 5 and, therefore, 
coming into a warmer climate, it is ready to dilTolve 
more j and, on this account, thefe winds, if they, 
continue long, are founu to be very dry and parch- 
ing, and are generally attended with fair weather. 
Thefe feem to be the principal effeds of heat and 
cold in caufing the air to dilTolve, aud take up, or 
let go, and precipitate the aqueous vapours, and . 
in conlequence of which we lometimes perceive 
changes of the weather, even when there is no • 
change in the height of the barometer. 
But condenfation and rarefaction will alfo have the;, 
like.efieds in promoting the folution of water in air, 
or in caufing fome part of what has been diffolved. 
to return again into water. and precipitate. It leems 
reafonable to fuppofe, that .denfe air, , in which the 
particles 
