ying power of a wire or circuit, without
heating. When heated there is an overload, or the
_capacity_ of the wire is overtaxed.

Capacity, Storage. The quantity of electricity in a secondary battery
when fully charged, usually reckoned in ampere hours.

Carbon. A material, like coke, ground or crushed, and formed
into sticks or plates by molding or compression. It
requires a high heat to melt or burn, and is used as
electrodes for arc lamps and for battery elements. It
has poor conductivity, and for arc lamps is coated
with copper to increase its conductivity.

Cell, Electrolytic. A vessel containing an electrolyte for
electroplating purposes.

Charge. The quantity of electricity on the surface of a body
or conductor.

Chemical Change. When a current passes through electrodes in a
solution, a change takes place which is chemical
in its character. Adding sulphuric acid to water
produces heat. If electrodes of opposite polarity are
placed in such an acid solution, a chemical change is
produced, which is transformed into electricity.

Choking Coil. An instrument in a circuit which by a form of
resistance regulates the flow of the current, or
returns part of it to the source of its generation.

Counter-electromotive Force. Cells which are inserted in opposition to
a battery to reduce high voltage.

Circuit, Astatic. A circuit in an instrument so wound that the earth's
magnetism will not affect it.

Circuit Breaker. Any instrument in a circuit which cuts out or
interrupts the flow of a current.

Circuit, External. A current flows through a wire or conductor,
and also along the air outside of the conductor,
the latter being the _external circuit._

Circuit Indicator. An instrument, like a galvanometer, that shows
the direction in which a current is flowing through
a conductor.

Circuit, Return. Usually the ground return, or the negative wire from
a battery.

Circuit, Short. Any connection between