attraction includes no maxima. There is then a _repulsion due to the
summative effects of strong opposite currents_ for a _lengthened
period_, against an _attraction_ due to the summative effects of _weak
currents_ of the _same direction_ during a _shortened period_, the
resultant effect being a greatly _preponderating_ repulsion.

It is now not difficult to understand all the actions before described
as obtained with the varied relations of coils, magnetic fields, and
closed circuits. It will be easily understood, also, that an alternating
magnetic field is in all respects the same as an alternating current
coil in producing repulsion on the closed conductor, because the
repulsions between the two conductors are the result of magnetic
repulsions arising from opposing fields produced by the coils when the
currents are of opposite directions in them.

Thus far I have applied the repulsive action described in the
construction of alternating current indicators, alternating current arc
lamps, regulating devices for alternating currents, and to rotary motors
for such currents. For current indicators, a pivoted or suspended copper
band or ring composed of thin washers piled together and insulated from
one another, and made to carry a pointer or index has been placed in the
axis of a coil conveying alternating currents whose amount or potential
is to be indicated. Gravity or a spring is used to bring the index to
the zero of a divided scale, at which time the plane of the copper ring
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.