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XX
LIGHT AND ELECTRICITY
·
example. Whatever we may think of its correctness, it is an
attempt which altogether formed a comprehensive system full
of scientific charm; those who were once attracted into its
magic circle remained prisoners there. And if the path indi-
cated was a false one, warning could only come from an intellect
of great freshness from a man who looked at phenomena
with an open mind and without preconceived opinions, who
started from what he saw, not from what he had heard, learned,
or read. Such a man was Faraday. Faraday, doubtless,
heard it said that when a body was electrified something
was introduced into it; but he saw that the changes which
took place only made themselves felt outside and not inside.
Faraday was taught that forces simply acted across space;
but he saw that an important part was played by the par-
ticular kind of matter filling the space across which the
forces were supposed to act. Faraday read that electricities
certainly existed, whereas there was much contention as to
the forces exercised by them; but he saw that the effects
of these forces were clearly displayed, whereas he could per-
ceive nothing of the electricities themselves. And so he
formed a quite different, an opposite conception of the matter.
To him the electric and magnetic forces became the actually
present, tangible realities; to him electricity and magnetism
were the things whose existence might be disputable. The
lines of force, as he called the forces independently considered,
stood before his intellectual eye in space as conditions of
space, as tensions, whirls, currents, whatever they might be
that he was himself unable to state-but there they were,
acting upon each other, pushing and pulling bodies about,
spreading themselves about and carrying the action from
point to point. To the objection that complete rest is the
only condition possible in empty space he could answer-Is
space really empty? Do not the phenomena of light compel
us to regard it as being filled with something? Might not
the ether which transmits the waves of light also be capable
of transmitting the changes which we call electric and
magnetic force? Might there not conceivably be some con-
nection between these changes and the light-waves. Might
not the latter be due to something like a quivering of the
lines of force ?