is a sectional view of the chamber in which the gas and air are mixed,
with the valves appertaining thereto; Fig. 5 is a detail view of the
ratchet plate, with pawl and levers and valve gear shaft; Fig. 6 is
a sectional view of a pump employed in some cases to circulate water
through the jacket; Fig. 7 is a sectional view of arrangement for
lighting, and ratchet plate, j, with central spindle and igniting
apertures, and the spiral spring, k, and fly nut, showing the attachment
to the end of the working cylinder, f1; b5, b5, bevel wheels driving
the valve gear shaft; e, the valve gear driving shaft; e2, eccentric to
drive pump; e cubed, eccentric or cam to drive exhaust valve; e4, crank to
drive ratchet plate; e5, connecting rod to ratchet pawl; f, cylinder
jacket; f1, internal or working cylinder; f2, back cylinder cover; g,
igniting chamber; h, mixing chamber; h1, flap valve; h2, gas inlet
valve, the motion of which is regulated by a governor; h3, gas inlet
valve seat; h4, cover, also forming stop for gas inlet valve; h5, gas
inlet pipe; h6, an inlet valve; h8, cover, also forming stop for air
inlet valve; h9, inlet pipe for air with grating; i, exhaust chamber;
i2, exhaust valve spindle; i7, exhaust pipe; j6, lighting aperture
through cylinder end; l, igniting gas jet; m, regulating and stop valve
for gas.

[Illustration: IMPROVED GAS ENGINE]

The engine, it will be seen, is single-acting, and no compression of the
explosive charge is employed. An explosive mixture of combustible gas
and air is drawn through the valves, h2 and h6, and exploded behind
the piston once in a revolution; but by a duplication of the valve and
igniting apparatus, placed also at the front end of the cylinder, the
engine may be constructed double-acting. At the proper time, when the
piston has proceeded far enough to draw in through the mixing chamber,