A method of working telegraph lines. When a signal is sent the line is charged. This has to be got rid of, and is an element of retardation. In double curb working it is disposed of by sending a momentary current first in the reverse, and then in the same, and finally in the reverse [...]

In duplex telegraphy the sending of two independent messages from the same end of the line in the same direction.

A variety of duplex telegraphy in which the messages are sent from opposite ends of the line, simultaneously, so as to be transmitted in opposite directions. (See Working, Diplex.)

In multiplex telegraphy the transmission of two messages, simultaneously, over one wire. (See Telegraphy, Multiple.)

The volt-coulomb, q. v., or watt-second, as it is often termed.

When a force acts upon a body and the body moves in the direction of the force, the force does work. Hence, work is the action of a force through space against resistance. It is generally expressed in compound units of length and weight, as foot-pounds, meaning a pound raised one foot.

A galvanometer or other instrument used for identifying the ends of a given wire in a cable containing several.

A method of winding disc and drum armatures. It consists in advancing the commutator ends of the U shaped turns progressively, so that as many commutator bars intervene between any two consecutive commutator connections of the wire as there are leads of wire on the drum between consecutive leads of the wire. This is carried [...]

A method of dynamo or motor-armature winding. A single groove passes longitudinally around the core and in this the wire is continuously wound. The system is not now used. The old Siemens’ H armature illustrates the principle.

A method of winding a generator or motor. Each commutator-brush has two connections. One set are the terminals of the outer circuit, the other set are the terminals of the field-magnet windings. In other words, the field-magnet windings are in shunt or in parallel with the outer circuit.