3.

Two supports, each 1/2 in. thick and 3 in. high, are fastened with
screws about half way between the end of the base and the upright
B, Fig. 1. The end view of these supports is shown in Fig. 2, at
GG. A 1/8-in. hole is bored through the top part of each support
so they will be in a line for the axle. The axle is made of a
piece of steel 1/8 in. in diameter and about 4 in. long. An offset
is bent in the center, as shown, for the crank. A small flywheel
is attached to one end of the shaft. The connecting rod E, Fig. 1,
is made of wood and fastened to the upper end of the driving arm D
with a small screw or nail. The contact F is made of a strip of
copper, 14 in. wide. This is to open and close the circuit when
the engine is running. The connections are made as shown in Fig.
1.

Connect two dry cells to the binding-posts and turn the flywheel.
The current passing through the magnet pulls the driving arm
toward the bolt head, which gives the shaft a half turn. The
turning of the shaft pulls the arm away from the copper piece F,
causing a break in the current. As the shaft revolves, the arm is
again brought back against the copper strip F, thus the current is
broken and applied at each revolution of the shaft. --Contributed
by S. W. Herron, Le Mars, Iowa.

** Child's Home-Made Swing Seat [276]

A very useful swing or seat for children can be made from a box or
packing case. Procure a box of the right size and saw it out in
the shape shown in the illustration. The apron or board in front
slides on the two front ropes. The board can be raised to place
the

[Illustration: Made of a Box]

child in the box and to remove him. The ropes are fastened to the
box by tying knots in their ends and driving staples over them.

** Clay Flower Pots Used for Bird Houses [277]

A novel use of the common garden flower pot may be made by
enlarging the small opening at the bottom with a pair of pliers,
and carefully breaking the clay away until the opening is large
enough to admit a small bird.

Place the pot, bottom side up, on a board, 3 in. wider than the
diameter of the largest pot used, and fasten it to the board with
wood cleats and brass screws. Fit the cleats as close as possible
to the sides of the pot. One or more pots may be used, as shown in
the sketch.

The board on which the pots are fastened is nailed or screwed to a
post or pole 10 or 12 ft. in height. The board is braced with lath
or similar strips