[6i] 
communicated to the thin fubftances, and to the air> 
and the light bodies placed beyond them. 
The only objedion to this hypothefis is, that this 
lateral force is not fo much lefs in vacuo as might be 
expeded, when the air is fuppofed to receive the 
concuflion firft, and to communicate it to other bo- 
dies j but it mull be confidered, that the mofl: perfed 
vacuum we can make with a pump is not free from 
air. I have tried to make this experiment in a Tor- 
ricellian vacuum^ but could not fucceed at that time. 
Betides, as the eledric matter, of which an explofion 
conlifts, muft take a wider path in vacuOy if not 
equally fill the whole fpace, it may affed a body in 
its paffage, v/ithout the intervention of any air. In 
condenfed air, this lateral force was not, as far as I 
could perceive, much increafed. 
Willing to feel what kind of an impulfe it was 
that aded upon bodies, when they were driven away 
by this lateral force of eledricity ; I held my finger 
near the path of an explofion of the battery, palling 
over the furface of a green leaf, when 1 felt a flroke, 
as of fomething pufliing againft my linger. Several 
corks, placed in the ftme lituation, were driven to a 
conliderable diflance by the fame explofion. 
Recolleding that this power, which .1 now call the 
lateral force of eledrical explofions, muft be the fame 
with that which gives the conculTion to water, men- 
tioned in my experiments to imitate an earthquake, 
and to vegetable and animal fubfiances, over the fur- 
face of which it pafles j and being determined to make- 
a more fatisfadory trial of it than I had ventured to 
do before, I laid a green leaf upon the palm of my 
hand, intending to make the explofion pals over the 
leaf ; 
