_A Model Signal._--First cut two strips of wood, half an inch wide and
as long as you can get them, which will be 8 or 9 in. These will stand
upright on a base board, and form the sides of the standard. Now between
these two you must glue shorter pieces of half-inch strip, so as to make
the standard solid at the top and bottom, and leave a hollow slot, 1 in.
long, in which the signal arm will fit and work up and down (Fig. 60).
[Illustration: 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).
[Illustration: 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).
[Illustration: 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).
[Illustration: 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.
The actual mechanism of the toy consists of a piece of catgut (an old
violin string, or a tennis-racket string). This passes through the
centre of a small flat piece of wood on which the two figures are
balanced. Just in front of the string a piece of wire (a bent hairpin
will do admirably) is fixed, so as to form a loop through which the
catgut can pass (see Fig. 64). The other end of the catgut is fixed to
the peg which fits in the hole in the roof.
[Illustration: FIG. 64.]
For the man and woman you can use two of the grotesque figures cut from
clothes pegs. Screws passed through the revolving base will secure the
figures firmly and at the same time add a little weight, and so improve
the balance.
When there is moisture in the air the catgut will twist. You must fit
together the different parts and then, by turning the peg to right or
left, adjust the position of the figures so that the lady appears in
fine weather and the gentleman in wet.