A common clock is merely a pendulum, with wheel-work
attached to it, to record the number of the vibrations; and with a weight
or spring, having force enough to counteract the retarding effects of
friction and the resistance of the air. The wheels show how many swings or
beats of the pendulum have taken place, because at every beat, a tooth of
the last wheel is allowed to pass. Now, if this wheel has sixty teeth, as
is common, it will just turn round once for sixty beats of the pendulum, or
seconds; and a hand fixed on its axis, projecting through the dial-plate,
will be the second hand of the clock. The other wheels are so connected
with this first, and the numbers of the teeth on them so proportioned, that
one turns sixty times slower than the first, to fit its axis to carry a
minute hand; and another, by moving twelve times slower still, is fitted to
carry an hour-hand.--_Arnott._
Why do clocks denote the progress of time?
Because they count the oscillations of a pendulum; and by that peculiar
property of the pendulum, that one vibration commences exactly where the
last terminates, no part of time is lost or gained in the juxtaposition (or
putting together) of the units so counted, so that the precise fractional
part of a day can be ascertained, which each such unit measures.
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