History of the Pendulum Clock

Just the Highlights

A pendulum clock uses a swinging weight as its timekeeping element. It was invented by Christiaan Huygens in 1656 and used in clocks until the 1930s. They were finicky, though. They had to be level and stationary to work and a lot of things like motion and temperature would affect their accuracy. Antique pendulum clocks are now kept mostly for their decorative and antique value.

The early pendulum clocks had a wide swing and made them inaccurate. By 1670, they invented the anchor escapement which allowed for smaller swings and resulted in better precision. That lead to long narrow clocks later called grandfather clocks.

From there, the deadbeat escapement invented by Richard Towneley in 1679 gradually replaced the anchor escapement and is still used in most modern pendulum clocks. By 1921, they realized temperature affected accuracy so George Graham invented the mercury pendulum. The mercury was placed in vials at the base of the pendulum and would expand or contract to compensate for temperature changes. This technique was mostly used in regulator clocks that were installed in public areas and used to set other clocks.

Pendulum clocks remained the world standard for accurate timekeeping for over 270 years until the invention of the quartz clock in 1927.