HOW IT WORKS.

HOUR-HAND TRAIN.

Fig. 211. —The hour-hand train of a clock.

The teeth of the mainspring drum gear with a cog on the minute-hand shaft, which also carries one of the cogs of the escapement train. The shaft is permitted by the escapement to revolve once an hour. Fig. 211 shows diagrammatically how this is managed. The hour-hand

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