Huygens, Christiaan 1629-93
Dutch physicist

He was born in The Hague, the second son of the poet Constantyn Huygens (1596-1687). He studied at the universities of Leyden and Breda, and his mathematical Theoremata was published in 1651. In 1655 he discovered the rings and fourth satellite of Saturn, using a refracting telescope he constructed with his brother. He later constructed the pendulum clock, based on the suggestion of Galileo (1657), and developed the latter's doctrine of accelerated motion under gravity. In 1663 he visited England, where he was elected FRS. He discovered the laws of collision of elastic bodies at the same time as John Wallis and Sir Christopher Wren, and improved the air-pump. In optics he first propounded the undulatory theory of light, and discovered polarization. The 'principle of Huygens' is a part of the wave theory. He lived for some years in Paris, a member of the Royal Academy of Sciences (1666-81), but later returned to The Hague. He was, after Isaac Newton, the greatest scientist of the second half of the 17th century.

Bibliography: Arthur E Bell, Christiaan Huygens and the Development of Science in the Seventeenth Century (1947)