d held together with small rivets.
Holes should be punched or drilled in the side of the firebox to give
the burner a sufficient supply of air. The burner is illustrated
clearly in Fig. 52. The fuel-tank can be made from an ordinary tin can
with the cover soldered on, and a hole made for a cork by means of which
it is filled with denatured alcohol. A little pipe runs from the
fuel-tank to the burner. It is advisable, if possible, to place a small
valve in this pipe to cut off the fuel supply when necessary. The only
other method of putting the burner out would be to stand it on its end.
The burner consists of a rectangular tin box with a top cut out as
illustrated. A piece of brass or copper gauze is placed in the top.
Asbestos wool is used to fill the can, and the alcohol is drawn into the
wool by capillary attraction, where it burns with a steady hot flame at
the surface of the copper gauze. In the corner of the can near the
feed-pipe another small piece of copper gauze is soldered as shown. This
covers up the feed-pipe entrance so that the asbestos will not plug up
the pipe.

[Illustration: FIG. 53]

[Illustration: FIG. 54]

The engine to be used in connection with the boiler just described is
shown in Fig. 53. This is a very simple engine of the oscillation type,
and there should be little trouble in making it. A more mechanical
drawing of the engine is shown in Fig. 54. The details of the engine are
shown in Fig. 55.

[Illustration: FIG. 55]

The cylinder of the engine should be made first. This is made from a
piece of brass tubing with an internal diameter of 3/4 inch. Two end
pieces, or a cylinder-end cover and cylinder head, must be cut to fit
inside the cylinder. These should be cut to shape from 1/16 inch brass,
and a hole drilled in the cylinder head 1/8 inch in diameter to
accommodate the piston-rod. The cylinder head is then soldered in place.
The cylinder-end cover should be left until the piston-rod and piston
are made.

The piston head is cut to shape from a piece of 3/16-inch sheet brass,
or it can be cut from a piece of 3/4-inch round brass with a hacksaw.
The piston-rod is soldered into a hole in the piston-head. A small
square piece of brass is placed on the opposite end of the piston-rod to
act as a bearing. This little piece is cut and drilled as shown in the
drawing. Before it is soldered in place on the piston-rod the
cylinder-end cover should be placed on the rod. Both the piston and the