Nikola Tesla U.S. Patent 723,188 - Method of Signaling Patent Wrapper Page 10

FLI JUILICIULI same manner and synchronized with the systems at the sending station, so as to respond each exclusively to one of the two vibrations produced by the transmitting apparatus. The same rules of adjustment are observed in the receiving circuits, care being furthermore taken that the synchronizing is effected when all the apparatus is connected to the circuits and placed in position, as any change may more or less modify the vibration. Bach of the receiving coils and s2 is shunted by a local circuit containing, respectively, sensitive devices al a², batteries, adjustable resistances and sensitive relays Rl R², all joined in series, as shown. The précise connections and arrangements of the various instruments are largely irmaterial, and may be varied in many ways. The sensitive devices al and a2 may be any of the well known devices ordinarily used, as for example, two conducting terminals e parated by a minute air-cap or thin film of dielectric, which is strained or weakened by a battery or other means to the point of breaking down, and gives way to the slightest disturbing influence. Its return to the normal sensitive state may be secured by momentarily interrupting the battery circuit after each operation, or otherwise. The relays R¹ R² e armatures 11, which are connected by a wire w, and when attracted, establish electrical contacts at and, thus closire a circuit containing a battery 33, en adjustable resistance and a relay R³. From the above description it will be readily seen that the relay R³ will be operated only when both contacts and ² are closed. The two vibrations at the sending station may be controlled in any suitable manner, as, for instance, by opening -6567