Radio-telegraphy

—An approved term for wirele telegraphy. The term is usually applied to long distance transmi ion of signals by means of electromagnetic waves projected through space without the intervention of insulated conductors þetween sending and receiving stations. Electric oscillations are generated at the sending station by means of an oscillator consisting e entially of a grounded spark gap terminating above in a vertical antenna carried upon a mast. These oscillations are projected by the antenna as electromagnetic waves which are caught at a receiving station by an aerial wire, transformed again into oscillations and detected by a sensitive device.