This ensures the pendulum doesn’t change length with temperature, but it still only brings the clock into the 0.1 second/day range.

Upgrade your home or office décor with the Le’raze Grandfather Wall Clock, a retro-looking polyresin wall clock in antique brown and bronze colors that comes with a swinging pendulum. We ...

The upper part, or hood, contained the clock itself; the middle, or waist, held the pendulum; the base provided support as well as a place for the clock's weights.

Huygens contracted his clock design (see image at right) to Dutch clockmaker Salomon Coster, who in 1657 actually built the clock. It is on display at the Boerhaave Museum in Leiden, the Netherlands.

When a pendulum clock is running properly, you should hear a rhythmic and even "TICK-TOCK." If you're hearing "tick-TOCK, tick-TOCK," your clock is not going to be running for long.

The front view (L) and side/schematic view (R) of the first pendulum clock ever built, in 1656/7, which was designed by Christiaan Huygens and built by Saloman Coster.