R
Radiant Energy. Energy existing in the luminiferous ether and exercised in wave transmission, creating light or sound. Radium possesses the highest form of radiant energy.
Radiate. To emit or send out in direct lines from a point or points, as radiating heat, light, or sound. The radiations are sent out in all directions from a central point, just as a stone thrown in a pond of still water will radiate waves or ripples from the central point.
Radiation. The travelling or motion of ether waves through space.
Radiator, Electric. A series of plates or wire-coils heated by current. They radiate heat and so warm the surrounding air.
Radiograph. A photographic picture taken by the X-ray process.
Receiver. In telephony or telegraphy, an instrument for receiving the message as distinguished from the instrument sending or transmitting the message.
The telephone piece held to the ear is the receiver.
Receiving End. The end of a line where the operative currents are received, as opposed to the end at which they are transmitted.
Receptacle. A device for the installation of an attachment or extension plug. Used in connection with electric-lighting circuits.