[ 5^5 ] 
grounded, and far from being fatisfadtory. In order 
to which I fhali only object to the lateft, (to avoid 
prolixity) which now has the general confent. 
I think the bafis, that this hypothecs hands on, is 
the authors affirming an analogy between thunder 
and fired gunpowder ; and then proving, that there 
are fulphureous and nitrous particles in the air, they 
leave them to take fire by fermentation, or fome 
other accident, and from thence to form thunder. 
Firft, the analogy is not juft ; for there is not any 
thing ftmilar to thunder in fired gunpowder, except 
the noife ; which may be lhewn from the different 
direction of their fire, and their very different effects. 
Fired gunpowder adts from a centre to a circumfe- 
rence, with equal force at equal diftances every wav, 
by propelling the circumambient air by the explofion 
it makes. The fire of thunder adts in rectilinear 
angles, (as I have often feen, and as any body may, 
who will obferve it) with fuch fubtil and diftindt 
effedts, as cannot be explain’d or imitated by the fire 
of gunpowder ; the hiftory of which effedts is too 
well known to need a repetition here 
I fhali go on to fhew fome infuperable difficulties 
in the formation and firing of this fuppofed aerial gun- 
powder. And firft, I think it inconceivable, that the 
fulphureous and nitrous particles fhould coalefce with 
fome other unknown third body, in the place of char- 
coal, in fuch exadt proportion, as is neceffary to make 
gunpowder of any perfedtion, and to form a body 
compadt enough to equal the noife of thunder, when 
fired in the open air. For fuch a body muft neceffa- 
rily defcend by its own gravity, long before it arrives 
to a bulk fufficient for the purpofe. And, fecondly, 
I think it contradictory to all experience, that fuch a 
collifion 
