After the researches which I have endeavoured to place before you,
it was impossible for Faraday to avoid taking a side in this
controversy. He did so in a paper 'On the Electricity of the
Voltaic Pile,' received by the Royal Society on the 7th of April,
1834. His position in the controversy might have been predicted.
He saw chemical effects going hand in hand with electrical effects,
the one being proportional to the other; and, in the paper now
before us, he proved that when the former was excluded, the latter
were sought for in vain. He produced a current without metallic
contact; he discovered liquids which, though competent to transmit
the feeblest currents--competent therefore to allow the electricity
of contact to flow through them if it were able to form a
current--were absolutely powerless when chemically inactive.

One of the very few experimental mistakes of Faraday occurred in
this investigation. He thought that with a single voltaic cell he
had obtained the spark before the metals touched, but he
subsequently discovered his error. To enable the voltaic spark to
pass through air before the terminals of the battery were united, it
was necessary to exalt the electro-motive force of the battery by
multiplying its elements; but all the elements Faraday possessed
were unequal to the task of urging the spark across the shortest
measurable space of air. Nor, indeed, could the action of the
battery, the different metals of which were in contact with each
other, decide the point in question. Still, as regards the identity
of electricities from various sources, it was at that day of great
importance to determine whether or not the voltaic current could
jump, as a spark, across an interval before contact. Faraday's
friend, Mr. Gassiot, solved this problem. He erected a battery of
4000 cells, and with it urged a stream of sparks from terminal to