of the subject has, after many years of patient perseverance, over come
many of the mechanical difficulties, and designed the engine of which
the above is an illustration.

The sectional elevation, shown in Fig. 1, is an expanded view of the
machine, shown thus to enable the action of the machine to be more
clearly understood; the relative position of the different parts, as
actually made, is shown in the side elevation (Fig. 4). The principal
working parts of the machine are the combustion chamber, D, which is of
the form shown, lined with fire brick, and having an entrance, with the
door screwed down like a manhole lid; the working cylinder, A,
surrounded by the water casing, K; the piston, B, with a water lining,
and coupled to the end of the working beam by a parallel motion, the
beam being supported by two rocking columns, Z, as in engines of the
"grasshopper" type; the air compressor, C, coupled directly to the
piston of the working cylinder; the injection pump, F, for supplying the
fuel--creosote or coal tar--to the combustion chamber; the regenerator
E; the receiver and separator, V Y; the feed and exhaust valves, M.

[Illustration: Fig. 1--SECTIONAL ELEVATION--HARGREAVES' THERMO-MOTOR.]

[Illustration: Fig. 2.]

The action of the machine is as follows: Assuming the engine to be in
condition for starting, the sides of the combustion chamber, D, are red
hot, the chamber charged with air, and the spray of creosote, injected
by the pump, F, is ignited; the expansion of the gases produced by the
combustion acts upon the bottom of the piston, B, forcing it to the top
of the cylinder, and thus, by intermediate mechanism, causing the crank
shaft to revolve. By the same stroke a charge of air is forced by the