92 - THEORY or 
tinually afcend till they arrive at it, leaving the denfer air, 
with which they were firft connected, behind. As thefe 
vapors move freely through and mix with air, they eafily 
infinuate themfelves between the particles of that fluid, 
and unite with it, whereby every particle of air whichy. 
from the caufes aforefaid, is become in any degree defti- 
tute of the quantity of eletric matter which is natural to 
it in its prefent ftate, may and will attraét and attach to 
itfelf one or more particles of this vapor, and thereby fur- 
nifh itfelf with a non-electric coating, and thus become 
qualified to receive from any neighbouring obje& fuch a 
{upply of the eledtric fluid as its ftate may demand. 
Thus provided, this body of air, together with the va- 
pors which are more or lefs attached to every particle of 
it, will conftitute a denfe cloud; and as the air itfelf was 
before (by fuppofition) in a craving or negative ftate of 
eleCtricity ; and as the vapors are prefumed to have arifen 
from the ocean in their natural or neutral ftate, the whole 
body of a cloud formed by them will ftill be ina negative 
ftate, and thereby conftitute a complete thunder cloud; 
which when formed, if uniform in denfity and contexture,. 
fhould it be attracted within the frzking diftance from any 
obje& ftanding upon the earth, would have its electric 
equilibrium reftored at once by a flafh of lightening dart- 
ing from the earth: Or fhould it pafs near another cloud 
in a different ftate, the flafh would reftore an equilibrium 
between. the two clouds. 
That a body of air, either in-a pofitive or negative ftate 
of electricity, while pure, fhould be incapable of commu- 
nicating its furplufage of the eleGtric element to, or re- 
ceiving fupplies from the neighbouring regions, though 
in a contrary ftate; and that the fame air, when replete 
with watery vapors, may be reftored to an equilibrium 
throughout its whole extent by an inftantaneous difcharge, 
may yet require fome further evidence before it be admitted. 
But, 
