Nikola Tesla U.S. Patent 723,188 - Method of Signaling Patent Wrapper Page 28

forth. 4. The method of signalling which consists in producing a plurality of series of electrical impulses of differcnt character, varying the time intervals between the emission of such impulses, exciting by the impulses of each series one of a plural ity of receiving circuits tuned to respond exclusively thereto and controlling by, such circuits a local circuit, as set forth." In submitting the application as thus anended for reconsideration, we desire to state that it is not our purpose in the amendment to limit the claims to a narrower scone than was contemplated originally, but merely to define with greater accuracy the distinctively novel feature of applicant's invention. The fundamental. idea of Mr. Tesla's inprovement is the use of a receiver comprising two or more circuits which are tuned to respond to impulses of differcnt character, and to the conjoint action of which the operation of the receiver is due. The pricr art, fairly though not fully illustrated by the patents cited by the Examiner, contains no instance of this principle of which we are aware. In systems of telegraphy currents, impulses or oscillations of different kinds have been transmitted to a receiver and by their conjoint effect an operation of the receiver produced, but in every instance where the receiver had more than one circuit, each circuit was either capable of responding to all of the currents or impulses or some rechanical device was employed for confining the action of one current or set of impulses to one circuit. The patent is representative of this latter class. The British patent to Wilson is believed to be for a purely theoretical and in-12Margin notes not legible - Ed.] Cardrell 585