The operation of the apparatus, as thus far described, will be more readily apparent from an inspection of Fig. 5. Assuming that the expansion coil there shown has been subject to a normal temperature of say 75 degrees Fahrenheit, and at that temperature the lever L is in the position shown in full lines on a decrease in temperature of say 10 degrees, the contraction of the coil, which will operate upon its entire length, will exert a pressure at the ends thereof in the direction of the arrows, the result of which will be to rotate the shaft J and raise the lever L against the force of the weighted lever K (carrying the latter therewith) to the position shown in dotted lines, thereby actuating the ratchet wheels M^{11}, M^{12}, and winding up the springs M^{9}, M^{10}, of the power-storage device, the force there stored being afterwards taken off, as required, through the medium of the power transmission shaft M¹ and spur wheel M² and any suitable gearing or power transmission means. The function of the flexible coupling indicated at M^{22} will now be quite clear. It will be seen that the coil spring N^{8} will be sufficiently strong not to give under the pull of the lever L except when the springs M^{9}, M^{10} are wound full. When that condition exists, the coil spring N^{8} will give, under the force of the lever L, and [Illustration: _Fig. 3._ BANGERTER’S PERPETUAL TIME CLOCK] no further power will be applied to the springs M^{9}, M^{10}. When, however, those springs have become unwound to a sufficient extent the spring N^{8} of the coupling M^{22} will be stronger than the springs of the power-storage device and will transmit, from the expansion coil, the force necessary to wind said springs as often as they become unwound; in other cases the force will be expended in simply compressing the coil spring N^{8} without effect upon the springs of the power-storage device. Referring now to what I will term the force-increasing devices, which are more clearly shown in Figs. 1, 2, 4, 8 and 9. Near each end of the upper knife-bar E, and contacting therewith at its under surface, is a support O, in the form of a flat-headed bolt (Fig. 8), the shank of said bolt passing through one end of lever O¹, which is fulcrumed at O² upon the upper surface of a cross-bar O³ securely fastened to the rear portion of the uprights C, C¹. To the front of said uprights is rigidly secured a second cross-bar O^{4}, and at the lower portion of said uprights and rigidly secured thereto is a third cross-bar O^{5}, against the under surface of which rests a lever O^{6} (Fig. 9) having its fulcrum point at O^{7}.