Earth.—A term for the return circuit, which for economy is formed through the earth in telegraph work. A return conductor common to many circuits is sometimes called “earth.”
Electrodes.—A term for the poles or plates leading the current into and out of a cell.
Electrolysis.—The act of decomposition by the electric current.
Electrolyte.—The liquid in a cell.
Electrometer.—An instrument for measuring electric potential.
Electro-motive Force (E. M. F.) (E).—The electric force tending to produce electric current. The Unit is the volt.
Erg.—The C. G. S. Unit of energy. The work of moving a body through 1 centimetre against the force of a dyne.
Extra Current.—The induced current of higher E. M. F., which appears in a wire wound in a helix when the current is broken.
Farad.—The Unit of capacity: a coulomb divided by a volt.
Field of Force.—The space between or around the poles of a magnet.