1. The power which electricity of tension possesses of causing an opposite
electrical state in its vicinity has been expressed by the general term
Induction; which, as it has been received into scientific language, may
also, with propriety, be used in the same general sense to express the
power which electrical currents may possess of inducing any particular
state upon matter in their immediate neighbourhood, otherwise indifferent.
It is with this meaning that I purpose using it in the present paper.

2. Certain effects of the induction of electrical currents have already
been recognised and described: as those of magnetization; Ampère's
experiments of bringing a copper disc near to a flat spiral; his repetition
with electro-magnets of Arago's extraordinary experiments, and perhaps a
few others. Still it appeared unlikely that these could be all the effects
which induction by currents could produce; especially as, upon dispensing
with iron, almost the whole of them disappear, whilst yet an infinity of
bodies, exhibiting definite phenomena of induction with electricity of
tension, still remain to be acted upon by the induction of electricity in
motion.

3. Further: Whether Ampère's beautiful theory were adopted, or any other,
or whatever reservation were mentally made, still it appeared very
extraordinary, that as every electric current was accompanied by a
corresponding intensity of magnetic action at right angles to the current,
good conductors of electricity, when placed within the sphere of this
action, should not have any current induced through them, or some sensible
effect produced equivalent in force to such a current.

4. These considerations, with their consequence, the hope of obtaining
electricity from ordinary magnetism, have stimulated me at various times to
investigate experimentally the inductive effect of electric currents. I