Pendulum Clock

A pendulum clock is a clock that uses a swinging weighted pendulum as its timekeeping element. The Dutch scientist Christiaan Huygens invented it on December 25, 1656, and patented the design the following year, having it built by the clockmaker Salomon Coster. Clocks before the pendulum were accurate to about fifteen minutes a day; Huygens' invention improved this roughly sixtyfold, to about fifteen seconds a day, and the pendulum clock remained the world's most precise type of timekeeper from 1656 until quartz clocks were developed in the 1930s, serving through the Industrial Revolution as the primary time standard for scheduling work, transportation and daily life before cheaper electric clocks began replacing it in homes from the 1930s and 1940s onward.