g
or band makes an angle of, say, 15 degrees to 20 degrees with the plane
of the coil. This angle is increased by deflection more or less great,
according to the current traversing the coil. The instrument can be
calibrated for set conditions of use. Time would not permit of a full
description of these arrangements as made up to the present.

In arc lamps the magnet for forming the arc can be composed of a closed
conductor, a coil for the passage of current, and an iron wire core. The
repulsive action upon the closed conductor lifts and regulates the
carbons in much the same manner that electro magnets do when continuous
currents are used. The electro-inductive repulsive action has also been
applied to regulating devices for alternating currents, with the details
of which I cannot now deal.

For the construction of an alternating current motor which can be
started from a state of rest the principle has also been applied, and it
may here be remarked that a number of designs of such motors is
practicable.

One of the simplest is as follows: The coils, C, Fig. 14, are traversed
by an alternating current and are placed over a coil, B, mounted upon a
horizontal axis, transverse to the axis of the coil, C. The terminals of
the coil, B, which is wound with insulated wire, are carried to a
commutator, the brushes being connected by a wire, as indicated. The
commutator is so constructed as to keep the coil, B, on short circuit
from the position of coincidence with the plane of C to the position
where the plane of B is at right angles to that of C; and to keep the
coil, B, open-circuited from the right-angled position, or thereabouts,
to the position of parallel or coincident planes. The deflective
repulsion exhibited by B will, when its circuit is completed by the
commutator and brushes, as described, act to place its plane at right
angles to that of C; but being then open-circuited, its momentum carries
it to the position just past parallelism, at which moment it is again
short-circuited, and so on. It is capable of very rapid rotation, but
its energy is small. I have, however, extended the principle to the
construction of more complete apparatus. One form has its revolving
portion or armature composed of a number of sheet iron disks wound as
usual with three coils crossing near the shaft. The commutator is
arranged to short-circuit each of these coils in succession, and twice
in a revolution, and for a period of 90-degrees