Galileo was probably the first person to notice the peculiar consistency of pendulums. While sitting in the Cathedral of Pisa, he supposedly took time to study the swinging chandeliers overhead. Timing the motion with his pulse, he discovered a regularity that, to him, seemed almost divine. Clockmakers, always a practical sort, were all too happy to take advantage of this principle and have been using it for centuries to regulate their timepieces.
Modern quartz movements like the one used in our clock no longer require pendulums to remain accurate. To many people, however, a clock without a pendulum just isn't a real clock. The spare open design of our pendulum clock uses the motion of the pendulum as its only adornment. The pendulum may not help the clock keep time, "and yet it moves."*