Page:The fairy tales of science.djvu/46

 formed of a hollow brass reel on which a long copper wire covered with silk is coiled. In the clock-case, on either side are magnets, fixed so that their opposite poles enter the reel.

Our readers have already been informed that a magnet freely supported, as in the mariner's compass, will move when the Amber Spirit passes over it. We will now confide to them another secret, namely, that a fixed magnet will give motion to a moveable wire along which the Spirit is passing. We shall now be able to explain the motion of our magic pendulum.

As soon as the Spirit is sent along the coil of wire, the pendulum moves towards one side, being attracted by the one magnet and repelled by the other; but by an ingenious contrivance the connexion between the coil and the battery is now broken, and the pendulum falls back by its own weight, again to be pulled aside by the magnets. The pendulum is thus made to oscillate; and so long as there is power enough in the battery to force the Spirit through the coil, it will keep swinging, and give motion to a series of wheels acting upon each other which carry round the hands of the clock.

Other methods have been devised to render the Spirit an effective time-keeper, but the simple arrangement we have described may be taken as the type of them all.