filings in motion while signals are being received. Fig. 7 shows the arrangement of the receiving apparatus. [Illustration: FIG. 3.--Photograph of the electric lines which emanate from the end of the wire at the sending station, and which are probably reproduced among the metallic filings of the coherer at the receiving station.] The coherer and the motor are shown between two batteries, one of which drives the motor while the other serves to work the bell or sounder when the electric wire excites the iron filings. In Fig. 2 this receiving apparatus is shown diagrammatically. B is the battery which sends a current through the sounder M and the coherer N when the magnetic whirls coming from the sending wire W embrace the receiving wire W'. [Illustration: FIG. 4.--Magnetic whirls about the sending wire.] The term wireless telegraphy is a misnomer, for without wires the method would not be possible. The phenomenon is merely an enlargement of one that we are fully conscious of in the case of telegraph and telephone circuits, which is termed electro-magnetic induction. Whenever an electric current suddenly flows or suddenly ceases to flow along a wire, electrical currents are caused by induction in neighboring wires. The receiver employed by Marconi is a delicate spark caused by this induction, which forms a bridge so that an electric current from the relay battery can pass and influence magnetic instruments. Many investigators had succeeded before Marconi in sending telegraphic messages several miles through the air or ether between two points not directly connected by wires. Marconi has extended the distance by employing a much higher electro-motive force at the sending station and using the feeble inductive effect at a distance to set in action a local battery. It is evident that wires are needed at the sending station from every point of which magnetic and electric waves are sent out, and wires at the receiving station which embrace, so to speak, these waves in the manner shown by our photographs. These waves produce minute sparks in the receiving instrument, which act like a suddenly drawn flood gate in allowing the current from a local battery to flow through the circuit in which the spark occurs, and thus produce a click on a telegraphic instrument. [Illustration: FIG. 5.--Magnetic whirls about the receiving wire.]