Nikola Tesla U.S. Patent 725,605 - System of Signaling Patent Wrapper Page 60

674 Referring to figure 1, suppose the circuit of the source S he kept closed and both transmitter circuits normally excited; then the receiving circuit will be continuously energized. If now, however, the period of one of the transmitter circuits be varied the corresponding circuit at the receiving station will cease to be energized and the receiver will be affected thereby. Thus the arbitrary variation of the period of one of the transmitting circuits. produces the same effect upon the receiver as opening or closing the circuit S. Even now, a receiver tuned to the ordinary rate of the varying transmitter circuit would by its failure to operate, as the period of the transmitter rose or fell from its normal rate, render the impulses intelligible, but if the operater change at will the period of either circuit alternately, as the statement above quoted implies, the actuation, or failure of actuation, of an intercepting receiver tuned to a normal rate, will convey no intelligence whatever. For its operation or control is not in any way dependent upon the signal, but upon the mere caprice of the sender. To illustrate another way, perhaps more convenient, for attaining the sara result with the apparatus shown in figure 1, the operator need only keep one of the transmitting circuits energized during an arbitrary time interval while he uses the other in the ordinary way for conveying a signal. If he changes. during the sending of his message from one to the other circuit, the intercepting receiver, no matter to which of the two transmitting circuits it may be tuned, will be incapable of recording more than meaningless dashes. There are, however, other ways shown or suggested in the specification which would enable the expert to secure what may -4