ded 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?' As far as electricity has been
applied for medical purposes, it has been almost exclusively Faraday's
electricity. You have noticed those lines of wire which cross the
streets of London. It is Faraday's currents that speed from place to
place through these wires. Approaching the point of Dungeness, the
mariner sees an unusually brilliant light, and from the noble phares
of La Heve the same light flashes across the sea. These are Faraday's
sparks exalted by suitable machinery to sunlike splendour. At the
present moment the Board of Trade and the Brethren of the Trinity House,
as well as the Commissioners of Northern Lights, are contemplating the
introduction of the Magneto-electric Light at numerous points upon our
coasts; and future generations will be able to refer to those guiding
stars in answer to the question. What has been the practical use of the
labours of Faraday? But I would again emphatically say, that his work
needs no such justification, and that if he had allowed his vision to
be disturbed by considerations regarding the practical use of his
discoveries, those discoveries would never have been made by him. 'I
have rather,' he writes in 1831, 'been desirous of discovering new
facts and new relations dependent on magneto-electric induction, than
of exalting the force of those already obtained; being assured that the
latter would find their full development hereafter.'

In 1817, when lecturing before a private society in London on the
element chlorine, Faraday thus expressed himself with reference to this
question of utility. 'Before leaving this subject, I will point out the
history of this substance, as an answer to those who are in the habit of
saying to every new