Fig. 60.
Now cut out and paint a signal arm, about 2-1/2 in. long. Fix this by means of a pin passing through the two sides of the standard, and through the arm about 3/4 in. from the square end. If it does not move easily in the slot, take off the top surface with glass-paper. Before fixing the signal arm in position, bore a small hole 1/4 in. from the square end, and knot in a piece of twine or thin wire to act as a connection between the movable arm and the controlling lever (Fig. 61).
Fig. 61.
At the base of the standard fix the controlling lever. This consists of a small strip, with a pin passing through one end into the standard. Adjust the length of the twine or wire, so that when the signal arm is down, the lever is horizontal; and when the lever is pressed down, the arm rises. You can make a little contrivance for fixing the lever by erecting a small post close to the standard, and gluing on two stops, under which to rest the free end of the lever in its two positions (Fig. 62).
Fig. 62.
If you prefer it, you can have the controlling lever at a distance from the signal post. You will then need a longer wire, and a little pulley wheel at the base of the standard. You must exercise your own ingenuity for this.
Another interesting little scientific toy, which has the additional advantage of being useful, is the Weather House, or the Man and Woman Barometer. This consists of a little house with two doorways, at which appear two figures, one in fine weather, and the other in dull (Fig. 63).