Nikola Tesla U.S. Patent 723,188 - Method of Signaling Patent Wrapper Page 24

al or relay R3, which in tum establishes a contact and brings into action a device a3 by means of a battery d included in a local circuit, as shown. But evidently, if through any extraneous disturbance only one of the circuits at the receiving station is affected, the relay R3³ will fail to respond. In this way a communication may be carried on with greatly increased safety against interference, and privacy of the messages may be secured. The receiving station shown in Fig. 2 is supposed to be one requiring no return message, but if the use of the system is such that this is necessary, then the two stations will be similarly equipped, and any well known reans, which it is not thought necessary to illustrate here, may be resorted to for enabling the apparatus at each station to be used in tum mitter and receiver. In like mammer the operation of a receiver, as R³, may be made dependent instead of upon two, upon more than two such transmitting systems or circuits, and thus any desired degree of exclusiveness or privacy and safety against extraneous disturbances may be attained. The apparatus as illustrated in Figs. 1 and 2 perrits, however, special results to be secured by the adjustment of the order of succession of the discharges of the primary circuits Pl and of p2, or the time interval between such discharges. To illust rate, the action of the relays R¹ R2 may be regulated either by adjusting the weights of the levers 1 12, or the strength of the batteries , or the resistances , or in other well known ways, so that, when a certain order between the discharges of the primary circuits Pl and P2 exists at the sending station, of succession or time interval as trans581