by the Elecivic Discharge, Sc. 4A7 
portional to its natural capacity, and to the quantity employed. 
at any one point in the circuit. For a discharge that will de- 
stroy a thin wire, would be conducted with safety by a wire of 
the same kind of metal, of greater dimensions. It now oc- 
curred, that those persons who had ignited gunpowder by the 
electric fluid, perhaps succeeded by using very narrow tubes 
filled with water. (For I had frequently transmitted a dis- 
charge through a wide tube without success; and as no author 
gives any dimensions of the water employed, it did not till 
now occur, that the time of transmission would vary with the 
calibre of the tube.) I had not at this time any narrow tubes 
in my possession. Considering, however, that if any non- 
conducting substance—such as silk, or paper,—were moistened 
with water, that those substances could have no more con- 
ducting power than what was imparted to them by the mois- 
ture; my first experiment was with a single thread of sewing- 
silk about four inches long, well moistened by drawing it 
between my lips. ‘This thread was made a part of the circuit 
between the inside and outside of a charged jar, At another. 
part of the circuit an interruption was made between the ex- 
tremities of two wires; and at this interruption was placed 
some gunpowder. On discharging the jar the gunpowder ig- 
nited. I repeated the experiment several times with the same 
success. I afterwards varied the experiment, by using the 
same thread and a smaller jar, and succeeded in igniting gun- 
powder with about thirty inches of charged surface. I must 
here observe, that when the thread was very wet, I never suc- 
ceeded with this small jar, owing, as I suppose, to the quan- 
tity of water contained in the thread being too great to retard 
the small quantity of electric fluid contained in the jar. For 
by squeezing out some of the moisture, the thread became a 
worse conductor, and then I always succeeded. 
I next tried how far it was possible to succeed with the first 
jar, and augmenting the quantity of water. For this purpose 
a piece of twine was used, well soaked in water. ‘This twine, 
however, conducted the electric fluid with too much facility 
to ignite the gunpowder; but when some of the moisture was 
squeezed out, it answered very well. ‘Thus, by proportioning 
the one with the other, I always succeeded. ‘The same re- 
sults were obtained by using moistened paper. 
Having satisfied myself ou this point, I next endeavoured 
to ascertain if the electric fluid undergoes any change in its 
physical character by passing through water; or if the ignition 
of gunpowder depends entirely on the time occupied by the 
fluid to pass through it. For this purpose I employed two 
jars, 
