The Pendulum Clock

The first accurate, modern clock was the pendulum clock. It was invented in 1656 by a Dutch scientist, Christian Huygens. When he first built the pendulum, it had an error of 1 minute per day. A lot of tweaking later, he had reduced it to only 10 seconds a day. The famous astronomer, Galileo Galilei, also dreamed up a pendulum design- but he never got to build it during his lifetime.
Different inventors later made improvements on Huygens’ invention. George Graham reduced the error margin to 1 second. John Harrison won an award for inventing a chronometer for use at sea. It was accurate to within 1/5 of a second. In 1889, Siegmund Riefier narrowed down the clock’s inaccuracy further to just 1/100 of a second. But his invention was overshadowed by the W.H. Shortt clock in 1921. The Shortt clock had two pendulums, with the “slave” pendulum pushing the “master” to move and also keeping the hands going.