Nikola Tesla U.S. Patent 723,188 - Method of Signaling Patent Wrapper Page 13

570 system e s³ at suitable intervals and causing two dis-, tinct vibrations to be emitted in rapid succession by the sender. In Fig. 4 a similar result is produced in the system e sí iª by periodically short circuiting the primary 24, by a rotating disk with insulating and conducting segments, or otherwise. Again, in Fig. 5 three distinct vibrations are caused to be emitted by a system e s5 d5, the result being produced by inserting periodically a suitable number of turns of an induction coil L in series with the oscillating sy stem by means of a rotating disk D5 with two projections 5 p5, and three rods or brushes 5, placed at an angle of one hundred and twenty degrees relative to each other. Corresponding to each of these cases, the receiving station may be provided with two or three circuits, in an analogous mammer to that illustrated in Fig. 2, it being understood, of course, that the different vibrations or disturbances emitted by the sender follow in such rapid suecession upon each other that they are practically simultaneous, as far as the operation of the relays, such as R1 and R2 is concerned. Evidently, however, it is not necessary to employ two or more receiving circuits, but single circuits may be used at the receiving stations arranged exactly as the transmitting circuits illustrated in Figs. 3, 4 and 5, in which case the corresponding disks, as D³, D², D5 at the sending station, will be driven in synchronism with those at the receiving end. But no matter what specific plan may be followed, it will be seen that the fundarental idea in my invention will always be carried out so as the operation of the receiver is made dependent on the -31