Pendulum clocks were the most common wall clocks for centuries, from its invention in 1656 by Christiaan Huygens well into the 20th century. This type of clock relies on a pendulum mechanism, by which the swinging motion of the pendulum (with its long maintained momentum) drives a set of gears that move the hands on the face of the clock.

Until the advance of the Quartz crystal clock in 1927, the pendulum clock maintained its popularity for almost three centuries thanks to its relative accuracy in measuring time. What was considered accurate in those days isn’t quit the same interpretation we have of this concept nowadays, which comes forward by the 15 seconds a day by which pendulum clocks would usually run late.

The first pendulum clocks only had a hand to indicate hours and had a long and relatively heavy pendulum arm. With shorter swings and the introduction of an anchor escapement mechanism (which helps the pendulum by providing precisely timed impulses to keep it swinging), accuracy was improved to such an extent that a minute hand could now be added to display time in more detail. This development accommodated the use of longer, slower pendulums which paved the way for grandfather clocks, with a pendulum that is encased within the extended frame of the clock.

The mechanism of a pendulum clock is built up of five parts:

• A power source, which is often a weight on a cord that turns a pulley through the force of gravity
• A gear train that increases the speed of the force applied by the weight, so it can be used by the pendulum
• An escapement that allows the pendulum to keep swinging through precisely timed impulses, and which also controls the gear train by allowing it to move forward a fixed amount at each swing of the pendulum
• The pendulum, which is usually a weight affixed to a rod and suspended from the clock’s internal mechanism
• An indicator that displays the amount of time the escapement has rotated, and in doing so shows how much time has passed (the face of the clock).

Pendulum clocks were very expensive up until the 19th century, since they were handmade by craftsman and were available mostly to the higher classes. The wealthy would often enrich the visual appeal of their clocks with rich ornamentation, which made the clock a showpiece of capital. The industrial evolution of the 1800s meant that factory production of clock parts was introduced, which made pendulum clocks much more affordable and thus available to middle class families.

Wall clocks with a similar style and appearance are mass produced at present day, with a fake pendulum and a simple battery-driven mechanism. Pendulum clocks are once again made by hand by specialists now. Although you pay more, the quality and craftsmanship are well worth the extra expense, which is affordable nevertheless.