Nikola Tesla Patents
468 5 fore referred to which performs this function will be stronger than normally, that is, when the sensitive device is not acted upon by the disturbances. Evidently then, if the receiver be so adjusted that it does not respond to the comparatively feeble normal discharges of the condenser, if they should occur, but only to those stronger ones which take place upon the diminution of the resistance of the sensitive device, it will be operated only when this device is acted upon by the disturbances, thus making it possible to investigate and to utilize the latter for any desired purpose. P The general principle underlying my invention, and the operation of the various devices used, will be clearly understood by reference to the accompanying drawing, 40 in which (Fig. is a diagram illustrating a typical arrangement of apparatus which may be used in carrying my method into practice, and Figs. 2, 3, 4, and 5, similar diagrams of modified arrangements of apparatus for the same purpose. In Fig. 1, C is a condenser to the terminals T and T' of which connected a charging circuit including a battery B, a sensitive device a and a resistance I, all connected in series as illustrated. The battery should be preferably of very constant electromotive force and of an intensity carefully determined to secure the best results. The resistance r, which may be a frictional or an inductive one, is not absolutely necessary, but it is of advantage to use it in order to facilitate adjustment, and for this purpose it may be made variable in any convenient and preferably continuous manner. Assuming that the disturbances which are to be in-8This page retyped from microfilm for better readability - Ed.]
