bar; (2) the shifting sleeve. The _rocking bar_ device is shown in Figs.
209, 210. The milled head M turns a cog, G, which is always in gear with
a cog, F. This cog gears with two others, A and B, mounted at each end
of the rocker R, which moves on pivot S. A spring, S P, attached to the
watch plate presses against a small stud on the rocking bar, and keeps A
normally in gear with C, mounted on the arbor of the mainspring.

[Illustration: FIG. 209.--The winding mechanism of a keyless watch.]

To wind the watch, M is turned so as to give F an anti-clockwise motion.
The teeth of F now press A downwards and keep it in gear with C while
the winding is done. A spring click (marked solid black) prevents the
spring uncoiling (Fig. 209). If F is turned in a clockwise direction it
lifts A and prevents it biting the teeth of C, and no strain is thrown
on C.

To set the hands, the little push-piece P is pressed inwards by the
thumb (Fig. 210) so as to depress the right-hand end of R and bring B
into gear with D, which in turn moves E, mounted on the end of the
minute-hand shaft. The hands can now be moved in either direction by
turning M. On releasing the push-piece the winding-wheels engage again.

The _shifting sleeve_ mechanism has a bevel pinion in the place of G
(Fig. 209) gearing with the mainspring cog. The shaft of the knob M is
round where it passes through the bevel and can turn freely inside it,
but is square below. On the square part is mounted a little sliding
clutch with teeth on the top corresponding with the other teeth on the
under side of the bevel-wheel, and teeth similar to those of G (Fig.
209) at the end. The clutch has a groove cut in the circumference, and
in this lies the end of a spring lever which can be depressed by the
push-piece. The mechanism much resembles on a small scale the motor car
changing gear (Fig. 49). Normally, the clutch is pushed up the square
part of the knob shaft by the spring so as to engage with the bevel and
the winding-wheels. On depressing the clutch by means of the push-piece
it gears with the minute-hand pinion, and lets go of the bevel.

[Illustration: FIG. 210.--The hand-setting mechanism in action.]

In one form of this mechanism the push-piece is dispensed with, and the
minute-wheel pinion is engaged by pulling the knob upwards.

THE HOUR-HAND TRAIN.

[Illustration: FIG. 211.--The hour-hand train of a clock.]

The teeth of the mainspring drum gear with a cog on