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).
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).
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).
With patience and care this is not very difficult to make. For the house itself you can use an old cigar box, or, if you prefer it, you can make the entire house in cardboard. This is, of course, easier, but not very durable. If you are going to use the cigar box, you will need first to cut the lid and bottom into something like the shape of a house end. You will then have to nail the lid down, and add two slanting pieces for the sides of the roof: and that will complete the house.
However, before you nail down the lid and put on the roof, you will need to understand the mechanism. First you will bore a round hole in the top of the roof, just behind the front gable. This hole is for a round peg to which the revolving base is attached.