The Europeans initially invented mechanical clocks to meet the needs of pious Christian monks who needed to know when it was time to pray. These early clocks did not show time, but rather they sounded it by striking bells at the appointed hours for prayer. These clocks did not have hours marked on their faces, nor did they have hands to point at the hour.
With regard to the importance of sounding the time, Robert Levine, in his book A Geography of Time, writes:
“The Middle English clok derived from Middle Dutch and German words for bell. The earliest mechanical timepieces were not technically considered clocks unless they sounded bells.”
The earliest mechanical clocks were water clocks (also known as clepsydrae). When these clocks were first invented, or the person(s) who invented them, are not known. Both the Greeks and the Romans used water clocks with complex gearing.
The major breakthrough in the development of telling time came in 1656 when the Dutch mathematician Christiaan Huygens designed the pendulum clock. The horologium, as he called it, was regulated by a pendulum which swings back and forth in a precise time interval which is determined by the length of the pendulum. The pendulum clock became the world’s most precise clock. The pendulum clock increased the accuracy of clocks from being “off” from about 15 minutes per day to about 15 seconds per day.
Huygens patented his new clock in 1657 and then had his clock designs constructed by Salomon Coster.
It should be pointed out that Galileo Galilei, who had started investigating pendulums in 1602, began investigating the use of pendulums in timekeeping devices about 1637. His son partly constructed a pendulum clock in 1649, but neither lived to finish the project.
The early pendulum clocks had fairly wide swings—up to 100”. In 1673, Huygens showed that the wide swings made the clocks less accurate. The use of the anchor escapement, which was invented in 1670, allowed for a narrower clock case. The long, narrow clocks, first made by William Clement about 1680, became known as grandfather clocks. By 1690, the minute hand began to appear on clock faces.
In 1675, Richard Towneley invented the deadbeat escapement which was then popularized about 1715 in his precision “regulator” clocks. As the world moved into the industrial revolution, precise timekeeping became important in regulating the flow of commerce, and the pendulum clock became more important.
One of the problems with pendulum clocks, however, is that they must remain stationary in order to operate. Motion affects the swing of the pendulum, causing inaccuracies. Thus, while the station master in a railroad station relied on a pendulum clock to check on the progress of trains, the engineer on board the train had to use some other form of timekeeping.
Shown above is a large grandfather clock on display in the Polson Museum in Hoquiam, Washington.
Shown above is a pendulum clock on display in the Polson Museum.