experiment, is found to be inappreciably small. The action will seem still
more instantaneous, because, as there is an accumulation of power in the
poles of the battery before contact, the first rush of electricity in the
wire of communication is greater than that sustained after the contact is
completed; the wire of induction becomes at the moment electro-tonic to an
equivalent degree, which the moment after sinks to the state in which the
continuous current can sustain it, but in sinking, causes an opposite
induced current to that at first produced. The consequence is, that the
first induced wave of electricity more resembles that from the discharge of
an electric jar, than it otherwise would do.

69. But when the iron cylinder is put into the same helix (31.), previous
to the connexion being made with the battery, then the current from the
latter may be considered as active in inducing innumerable currents of a
similar kind to itself in the iron, rendering it a magnet. This is known by
experiment to occupy time; for a magnet so formed, even of soft iron, does
not rise to its fullest intensity in an instant, and it may be because the
currents within the iron are successive in their formation or arrangement.
But as the magnet can induce, as well as the battery current, the combined
action of the two continues to evolve induced electricity, until their
joint effect is at a maximum, and thus the existence of the deflecting
force is prolonged sufficiently to overcome the inertia of the galvanometer
needle.

70. In all those cases where the helices or wires are advanced towards or
taken from the magnet (50. 55.), the direct or inverted current of induced
electricity continues for the time occupied in the advance or recession;
for the electro-tonic state is rising to a higher or falling to a lower
degree during that time, and the change is accompanied by its corresponding
evolution of electricity; but these form no objections to the opinion that