s) of a car, from which the body has been
removed. Starting at the left, we have the handle for setting the
engine in motion; the engine (a two-cylinder in this case); the
fly-wheel, inside which is the clutch; the gear-box, containing the cogs
for altering the speed of revolution of the driving-wheels relatively to
that of the engine; the propeller shaft; the silencer, for deadening the
noise of the exhaust; and the bevel-gear, for turning the
driving-wheels. In the particular type of car here considered you will
notice that a "direct," or shaft, drive is used. The shaft has at each
end a flexible, or "universal," joint, which allows the shaft to turn
freely, even though it may not be in a line with the shaft projecting
from the gear-box. It must be remembered that the engine and gear-box
are mounted on the frame, between which and the axles are springs, so
that when the car bumps up and down, the shaft describes part of a
circle, of which the gear-box end is the centre.

An alternative method of driving is by means of chains, which run round
sprocket (cog) wheels on the ends of a shaft crossing the frame just
behind the gear-box, and round larger sprockets attached to the hubs of
the driving-wheels. In such a case the axles of the driving-wheel are
fixed to the springs, and the wheels revolve round them. Where a Cardan
(shaft) drive is used the axles are attached rigidly to the wheels at
one end, and extend, through tubes fixed to the springs, to bevel-wheels
in a central compensating-gear box (of which more presently).

Several parts--the carburetter, tanks, governor, and pump--are not shown
in the general plan. These will be referred to in the more detailed
account that follows.

THE STARTING-HANDLE.

[Illustration: FIG. 41.--The starting-handle.]

Fig. 41 gives the starting-handle in part section. The handle H is
attached to a tube which terminates in a clutch, C. A powerful spring
keeps C normally apart from a second clutch, C^1, keyed to the engine
shaft. When the driver wishes to start the engine he presses the handle
towards the right, brings the clutches together, and turns the handle in
a clockwise direction. As soon as the engine begins to fire, the faces
of the clutches slip over one another.

THE ENGINE.

[Illustration: FIG. 42.--End and cross sections of a two-cylinder
motor.]

We next examine the two-cylinder engine (Fig. 42). Each cylinder is
surrounded by a water-jacket, through which wat