that is to say, on January 29, 1835--Faraday read before the Royal
Society a paper 'On the influence by induction of an electric
current upon itself.' A shock and spark of a peculiar character had
been observed by a young man named William Jenkin, who must have
been a youth of some scientific promise, but who, as Faraday once
informed me, was dissuaded by his own father from having anything to
do with science. The investigation of the fact noticed by Mr. Jenkin
led Faraday to the discovery of the extra current, or the current
induced in the primary wire itself at the moments of making and
breaking contact, the phenomena of which he described and
illustrated in the beautiful and exhaustive paper referred to.

Seven-and-thirty years have passed since the discovery of
magneto-electricity; but, if we except the extra current, until
quite recently nothing of moment was added to the subject. Faraday
entertained the opinion that the discoverer of a great law or
principle had a right to the 'spoils'--this was his term--arising
from its illustration; and guided by the principle he had discovered,
his wonderful mind, aided by his wonderful ten fingers, overran in a
single autumn this vast domain, and hardly left behind him the shred
of a fact to be gathered by his successors.

And here the question may arise in some minds, What is the use of it
all? The answer is, that if man's intellectual nature thirsts for
knowledge, then knowledge is useful because it satisfies this
thirst. If you demand practical ends, you must, I think, expand your
definition of the term practical, and make it include all that
elevates and enlightens the intellect, as well as all that ministers
to the bodily health and comfort of men. Still, if needed, an answer
of another kind might be given to the question 'What is its use?'