n he found
that the instrument occupied by the 'solid dielectric' takes more than
half the original charge. A portion of the charge was absorbed by
the dielectric itself. The electricity took time to penetrate the
dielectric. Immediately after the discharge of the apparatus, no trace
of electricity was found upon its knob. But after a time electricity was
found there, the charge having gradually returned from the dielectric
in which it had been lodged. Different insulators possess this power
of permitting the charge to enter them in different degrees. Faraday
figured their particles as polarized, and he concluded that the force of
induction is propagated from particle to particle of the dielectric from
the inner sphere to the outer one. This power of propagation possessed
by insulators he called their 'Specific Inductive Capacity.'

Faraday visualizes with the utmost clearness the state of his contiguous
particles; one after another they become charged, each succeeding
particle depending for its charge upon its predecessor. And now he seeks
to break down the wall of partition between conductors and insulators.
'Can we not,' he says, 'by a gradual chain of association carry up
discharge from its occurrence in air through spermaceti and water, to
solutions, and then on to chlorides, oxides, and metals, without any
essential change in its character?' Even copper, he urges, offers
a resistance to the transmission of electricity. The action of its
particles differs from those of an insulator only in degree. They are
charged like the particles of the insulator, but they discharge with
greater ease and rapidity; and this rapidity of molecular discharge is
what we call conduction. Conduction then is always preceded by atomic
induction; and when, through some quality of the body which Faraday
does not define, the atomic discharge is rendered slow and difficult,
conduction passes into insulation.

Though they are often obscure, a fine vein of philosophic thought runs
through those investigations. The mind of the philosopher dwells amid
those agencies which underlie the visible phenomena of Induction and
Conduction; and he tries by the strong light of his imagination to see
the very molecules of his dielectrics. It would, however, be easy to
criticise these researches, easy to show the looseness, and sometimes
the inaccuracy, of the phraseology employed; but this critical spirit
will get little good out of Faraday. Rather let tho