Nikola Tesla Patents
266 and a current traverses the relay magnet a. The particular sensitive device employed is shown in general views and in detail in Figs. 4, 6, 7 and 8. It consists of a metal cylinder c with insulating heads c', through which passes a central metallic rod c". A small quantity of grains d of conducting material, such as an oxidized metal is placed in the cylinder. A metallic strip d', secured to an insulated post d", bears against the side of the cylinder c, connecting it with the conductor C forming one part of the circuit. The central rod c" is connected to the frame of the instrument and so to the other part of the circuit through the forked metal arm e, the ends of which are fastened with two nuts to the projecting ends of the rod, by which means the cylinder c is supported. 90 In order to interrupt the flow of battery current which is started through the action of the sensitive device A special are provided, which are as follows: The armature e of the magnet a, when attracted by the latter, closes a circuit containing a battery b' and magnet f. The armature lever f' of this magnet is fixed to a rock shaft I", to which is secured an anchor escapement which controls the movements of a spindle g' driven by a clock train K. The spindle g' has fixed to it a disk " with four pins b", so that for each oscillation of the escapement g the spindle is turned through one quarter of a revolution. One of the spindles in the clock train, as h, is geared so as to make one half of a revolution for each -13
