by the Electric Discharge, c. 449 
to be useful; for it may be administered to any particular part 
of the body without affecting any other part. It may be ap- 
plied to the skin of the most delicate patient; and without the 
least danger of giving a shock, a most powerful stream of 
electricity may be poured on the part affected. 
It has been also ascertained, that the force of an electric dis- 
charge through metal, is always proportioned to the thickness 
of the wire through which it is transmitted; or, that the same 
quantity and intensity of electric fluid acts with a greater force 
when transmitted through a thick, than through a thin wire. 
This law of course has a limit; for if the conducting wire 
be sufficiently stout or capacious to transmit the fluid without 
interruption, a wire of larger dimensions can give no more 
facility to the transmission. I am of opinion, however, that 
thick wire facilitates the transmission of the electric fluid to a 
greater degree than is generally suspected. 
Now it is evident, that as thin wire has the property of di- 
minishing the intensity of an electrical discharge, the fluid 
during its transmission through such a wire must necessarily 
be drawn out (as it were) into a longer stream, than if it were 
transmitted through a thick one. In the same manner that a 
certain quantity of water would be drawn out into a longer 
stream, by passing through a narrow than through a wide 
tube; or as a piece of metal would be drawn into a longer 
wire by passing through a small than through a large hole 
in the plate. 
Hence it became a curious question, What length of wire 
of a given dimension, does a certain quantity of the electric 
fluid (say a jar charged to a certain intensity) occupy, at any 
moment during its transmission? I supposed that this might 
probably be ascertained by placing some gunpowder at an in- 
terruption near to the positive side of the jar, and the mois- 
tened thread near to the negative side, having a long copper 
wire between them. For if the wire was of sufficient dimen- 
sions to contain all the fluid at once, the latter would not meet 
with any resistance till it arrived at the moistened thread ; and 
the time of its transmission through that part of the circuit 
where the gunpowder was placed, would not be lengthened ; 
upon which supposition, the gunpowder ought not to be ig- 
nited. 
With such arrangements, I have separated the gunpowder 
and moistened thread by a copper wire, No. 16, of different 
lengths, from one to twenty yards; yet with all this length of 
good conducting substance beyond the gunpowder, the latter 
never failed to be ignited. 
I consider this a very curious circumstance, and the inquiry 
Vol. 67. No. 338. June 1826. $L important. 
