Dr. Eafon on the Ajcent of Vapour. 399 
Cold northern countries, than in warm fouthern 
places. Mr. Volta, with a very fimple apparatus, 
on the upper gallery of St. Paul’s, produced 
an eledric fpark, which, he told me, in Italy, 
could not be done, but on a very high moun¬ 
tain, or in a fituation greatly elevated. This 
feems a wife provifion in nature, that the eledric 
matter fhould appear near the furface of the 
earth in cold climates, to raife up and fufpend 
the vapour in the air, which otherways, would 
be condenfed by the cold; whereas, in warm 
countries, the heat of the earth will be fufficient 
to raife vapours to a great height, which are 
afterwards carried ftill higher, by the eledric 
matter in the upper regions. This, perhaps, 
is the caufe, why the air is fo clear and tranfpa- 
rent in warm climates. 
By making fome obfervations on the falling 
of rain, we fhall have other proofs, that the 
eledric matter is the great caufe, by which 
vapour is fupported in the atmofphere. Here 
I mull obferve a fad, well known to ail prefent, 
that bodies eledrified, by the fame eledric 
power (no matter whether pofitive or negative) 
repel each other ; and when eledrified by the 
different powers, that is, the one plus and the 
other minus, attrad each other: on coming into 
contad, an equilibrium is reftored, and neither 
of them will fhew any figns of eledricity. 
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