Grandfather clocks

An ordinary pendulum swings in the arc of a circle and doesn’t have a constant period (?). But a cycloid trajectory enables a constant period. The clock involved counterweights and a cycloid always pendulum and could tell time far better than its predecessor.
 Christian Huygens Netherlands 1656 Grandfather clocks

An ordinary pendulum swings in the arc of a circle and doesn’t have a constant period (?). But a cycloid trajectory enables a constant period. The clock involved counterweights and a cycloid always pendulum and could tell time far better than its predecessor.