Relay, Repeating. In telegraphy, a relay for repeating the signals through a second line.
Reluctance. Magnetic resistance.
Repeater. In telegraphy, an instrument for repeating the signals through a second line. It is virtually a relay which is controlled by the sender, and which, in turn, operates the rest of the main line. It is usually located at about the middle of the total distance covered.
Repeating-station. A telegraph station located on a long line, and occupying a position at the juncture of the sections into which the line is divided. The currents received through one section are repeated into the other sections by means of a repeater.
Repulsion, Electric. The tendency which exists between two bodies charged alike to mutually repel each other.
Residual Charge. (See [Charge, Residual].)
Resilience. The power to spring back to a former position. Electricity is resilient, although its elasticity cannot be measured accurately.
Resin. A solid inflammable substance or gum, and a good non-conductor in electrical work. It is the product obtained by distilling the sap of the pitch-pine. The name is also applied to the product of distilling the sap of other trees. Common resin, shellac, lac, Dragon’s-blood, and other substances of a similar nature are resins. They are all dielectrics, and the source of negative frictional electricity when rubbed with cotton, wool, flannel, silk, or fur.
Resistance. That quality of an electric conductor in virtue of which it opposes the passage of an electric current, causing the disappearance or modification of electro-motive force, and converting electric energy into heat energy.
Resistance-box. A box filled with resistance-coils connected in series and provided with a switch, so that any number of the coils may be cut out.