er of a permanent magnet of the horse-shoe type, and connects the
ends of this coil to a galvanometer. He discovers that whenever the
armature is placed against the magnet poles, and is therefore being
rendered magnetic by contact therewith, the deflection of the needle of
the galvanometer shows that the coiled wire on the armature is traversed
by a current of electricity; that whenever the armature is removed from
the magnet poles, and is therefore losing its magnetism, the needle of
the galvanometer is again deflected, but now in the opposite direction,
showing that an electric current is again flowing through the coiled
wire on the armature, but reversed in direction. He notices, too, that
these effects take place only while changes are going on in the strength
of the magnetism in the armature, or when magnetic flux is passing
through the coils; for, the galvanometer needle comes to rest, and
remains at rest as long as the contact between the armature and the
poles remains unbroken.

In another experiment he employs a simple hollow coil, or helix, of
insulated wire whose ends are connected with a galvanometer. On suddenly
thrusting one end of a straight cylindrical magnet into the axis of the
helix, the deflection of the galvanometer needle showed the presence of
an electric current in the helix. The magnet being left in the helix,
the galvanometer needle came to rest, thus showing the absence of
current. When the bar magnet was suddenly withdrawn from the helix, the
galvanometer needle was again deflected, but now in the opposite
direction, showing that the direction of the current in the helix had
been reversed.

The preceding are but some of the results that Faraday obtained by
means of his experimental researches in the direct production of
electricity from magnetism. Let us now briefly examine just what he was
doing, and the means whereby he obtained electric currents from
magnetism. We will consider this question from the views of the present
time, rather than from those of Faraday, although the difference between
the two are in most respects immaterial.

Faraday knew that the space or region around a magnet is permeated or
traversed by what he called magnetic curves, or lines of magnetic force.
These lines are still called "lines of magnetic force," or by some
"magnetic streamings" "magnetic flux," or simply "magnetism." They are
invisible, though their presence is readily manifested by means of iron
filing