Huygens pendulum clock, 1673.
© Science Museum / Science & Society Picture Library
Reconstruction of a clock movement described in 'Horologium Oscillatorium' (1673) by Christiaan Huygens (1629-1695), with bras seconds dial and additional minutes dial. Although Galileo (1564-1642) had experimented with pendulums, the Dutch scientist Huygens was the first to master and profit from them. He attached a pendulum to the gears of a mechanical clock. The regular swing of the pendulum allowed the clock to achieve greater accuracy, as the hands are turned by the falling weight, which releases the same amount of energy with each tick.