ck, impelled backward through the latter an electric wave, which
subsided as soon as the primary current was fully established.

Faraday, for a time, believed that the secondary wire, though quiescent
when the primary current had been once established, was not in its
natural condition, its return to that condition being declared by the
current observed at breaking the circuit. He called this hypothetical
state of the wire the _electro-tonic state_: he afterwards abandoned
this hypothesis, but seemed to return to it in after life. The term
electro-tonic is also preserved by Professor Du Bois Reymond to express
a certain electric condition of the nerves, and Professor Clerk Maxwell
has ably defined and illustrated the hypothesis in the Tenth Volume of
the "Transactions of the Cambridge Philosophical Society."

The mere approach of a wire forming a closed curve to a second wire
through which a voltaic current flowed was then shown by Faraday to be
sufficient to arouse in the neutral wire an induced current, opposed in
direction to the inducing current; the withdrawal of the wire also
generated a current having the same direction as the inducing current;
those currents existed only during the time of approach or withdrawal,
and when neither the primary nor the secondary wire was in motion, no
matter how close their proximity might be, no induced current was
generated.

Faraday has been called a purely inductive philosopher. A great deal of
nonsense is, I fear, uttered in this land of England about induction and
deduction. Some profess to befriend the one, some the other, while the
real vocation of an investigator, like Faraday, consists in the
incessant marriage of both. He was at this time full of the theory of
Ampere, and it cannot be doubted that numbers of his experiments were
executed merely to test his deductions from that theory. Starting from
the discovery of Oersted, the celebrated French philosopher had shown
that all the phenomena of magnetism then known might be reduced to the
mutual attractions and repulsions of electric currents. Magnetism had
been produced from electricity, and Faraday, who all his life long
entertained a strong belief in such reciprocal actions, now attempted to
effect the evolution of electricity from magnetism. Round a welded iron
ring he placed two distinct coils of covered wire, causing the coils to
occupy opposite halves of the ring. Connecting the ends of one of the
coils with a galv