[ 6y6 ] 
water can be brought about, but by fuppofing its 
elafticity to be increafed, by the motion of the elec- 
tric fluid through it, unlefs you fuppofe it to be ac- 
tually pufhed afide, by the force with which the 
cleftric fluid endeavours to iffue from the over- 
charged body : but I can by no means think, that 
the force with which the fluid endeavours to ilTue, 
in the ordinary cafes in which eledlric fparks are pro- 
duced, is fufficient to overcome the prefTure of the 
atmofphere, much lefs that it is fufficient to burft 
the glafs vefTels in Beccaria’s and Lane’s experi- 
ments. 
The truth of this is confirmed by Prop. XVI. 
For, let an undercharged body be brought near to, 
and oppofite to the end of a long cylindrical body 
communicating with the ground, by that propofition 
the preflure of the electric fluid againfl: the bafe of 
the cylinder is fcarcely greater than the force with 
which the two bodies attradl each other, provided 
that no part of the cylinder is undercharged ; which is 
very unlikely to be the cafe, if theeledric repulfion is 
invcrfely as the fquare of the diilance, as I have great 
reafon to believe it is; and, confequently, if the 
fpark was produced, by the air being puflied afide by 
the force with which the fluid endeavours to iffue 
from the cylinder, no fparks fhould be produced, un- 
lefs the eleftricity was fo ftrong, that the force with 
wffiich'the bodies attradled each other was as great as 
the prefTure of the atmofphere againfl the bafe of the 
cylinder : whereas it is well known, that a fpark 
may be produced, when the force, with which the 
bodies attraft, is very trifling in refpedl of that. 
