-[ 662 ] 
C<jivc electricity from the air, it negatively electrified, 
and part with fome to jt if pofitively eieClrified: and 
a body not eleCtrified and not infulated receives 
electricity from the air if brought near an overcharged 
body, and loles fome when brought near an under- 
charged body : and a body infulated and containing 
its natural quantity of fluid, in fome cafes, receives, 
and in others lofes eleCtricity, when brought near an 
over or undercharged body, 
§ 4. The weli-known efteCls of points in caufing 
a quick dilcharge of deClricity teem to agree very 
well with this theory. 
It appears from the 20‘h propofidon, that if two 
fimilar bodies of different fizes are placed at a very 
great diftance from each other, and conncCled by a 
flendcr canal, and overcharged, the force witn which 
a particle^ of fluid placed clofe to correfponding parts 
nf their lurface is repelled from them, is inveiiely as 
the correfponding diameters of the bodies. If the 
diflance of the two bodies is fmall, there is not fp 
much difference in tne force with which tlie particle 
is repelled by the two bodies ; but flill, if the diarne- 
lefs of the two bodies are very different, the particle 
wmII 1^ repelled wnth much more force from th*e 
finaller body than from the larger. It is true indeed 
tnat a particle placed at a certain diflance from the 
[mailer body, will be repelled with lefs. force than if 
It bi- placed at the fime diflance from the greater 
body but this d.fl.ince is, I believe, in mofl cafes 
pretty confidgrahle ; if the bodies are fpherical, and 
th$ tepulfion inveifdly as the fquare of the oiflancc, u 
jitticle plav^cd at any diflance Irom the furfaccof the 
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