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Christiaan Huygens

Christiaan HuygensChristiaan Huygens Christiaan Huygens (1629–95) was a Dutch mathematician and scientist. One of his greatest contributions to science was his proof that light travelled in the form of waves. He is also known for drawing the first map of the surface of Mars, and for his studies of the rings of Saturn and the discovery of its moon, Titan. His astronomical discoveries were made possible by the techniques Huygens and his brother Constantijn invented for making telescope lenses. His greatest invention, however, was made in 1656: the pendulum clock. This greatly increased the accuracy of clocks, from minutes to seconds per day.


Verge escapement and foliotVerge escapement and foliot

From foliot to pendulum

Before Huygens' time, all mechanical clocks were driven by some kind of "oscillator", a device that repeated the same motion with a constant time interval between repetitions. Until Huygens' invention of the pendulum clock, these oscillations were provided by a foliot balance controlled by a verge escapement.


How a verge escapement worksHow a verge escapement works

An escapement is the mechanism that controls the movement of a clock by allowing the cogs to advance at regular intervals or "ticks". The movement of the clock was controlled by flat plates, called pallets, attached to the vertical shaft, the verge, on top of which was a bar, called the foliot, which had weights hanging from either end.

This animation shows how the pallets control the turning movement of the cog, which is connected to the clock hand.

Before the invention of the pendulum, very few clocks had minute hands because the time which they showed might have been wrong by several minutes. Huygens' new clock was reliable enough for him to fit it with a minute hand and a second hand.

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