[ 373 J 
within my notice, in one particular branch of elec- 
tricity, that which relates to the Leyden phial. 
All who allow of pofitive and negative electricity, 
know, that the phial, when charged, exhibits elec- 
tricity in thofe two dates, the one within, the other 
on the outfide ; and that when a communication is 
made between the two, by the means of a non-elec- 
tric touching the coating, and at the fame time ap- 
proaching the wire, or vice verfa , the explofion is 
produced, and the phial difcharged. This reduces 
the quedion to a narrow compafs ; for if, upon the 
difcharge of the phial, we meet with proofs not only 
of a power aCting from within to the outfide, but alfo 
of a power aCting at the fame inftant from the out- 
lide to within, then, I think, we may fairly conclude, 
that what is called negative electricity is, in reality, a 
pofitive adlive power; and that eleCtricity, in gene- 
ral, confids not of one alone, but of two diftinCt, 
pofitive powers, aCting in contrary directions, and 
towards each other. 
The proof I fliall offer firft, is founded on the fol- 
lowing experiment. When the phial is electrified but 
a little, if we touch the coating of it with a finger of 
one hand, and at the fame time approach a finger of 
the other hand to the wire, we fhall receive a pretty 
fmart blow upon the tip of each of the fingers, the 
fenfation of which reaches no farther : If the phial 
be electrified a degree higher, we fliall feel a ftronger 
blow, reaching to the wrids, but no farther : When 
again it is electrified to a dill higher degree, a feverer 
blow will be received ; but will not be felt beyond the 
elbows : Ladly, when the phial is drongly charged, 
the ftroke may be perceived in the wrifts and elbows ; 
