Christian Huygens Biography
HUYGENS, CHRISTIAN (1629-95). A Dutch mathematician, physicist, and astronomer. He was born at The Hague, a sop of Constantijn Huygens. He studied at Leyden and Breda, devoting himself at first to law and then pursuing the study of mathematics. At the invitation of Minister Solbert of France, he settled in Paris, being given rooms in the Royal Library and made a member of the Academy. After the revocation of the Edict of Nantes he returned to Holland, where he lived the rest of his life. His early work, Theoremata de Quadratura Hyperbolis, Ellipsis, et Circuli, ex Dato Portionum Gravitatis Centro (1651), is an example of the talent which lay at the foundation of all his scientific achievements. This was followed by his De Circuli Magnitudine Inventa (Leyden, 1654), reprinted in Rudio, Archimedes, Huygens, Lambert, Legendre (Leipzig, 1892), the object of each work being to expose the fallacies of Gregoire de Saint-Vincent. He also worked on the doctrine of probabilities already founded by Pascal and Fermat and published De Ratiocinatione in Ludo Aleae; (1656). Huygens was the first to apply the pendulum to clocks and to use the device to determine the acceleration of gravity. A complete description of Huygens's apparatus is contained in his great work, Horologium 0scillatorium, sive de Motu Pendulorum (1673) . He also developed and gave precision to the investigations of Galileo upon accelerated motion under the action of gravity; and there is no doubt that to his studies and discoveries his great successor, Newton, in preparing his magnificent development of the principle of accelerating force, was largely indebted. Newton was a student and admirer of his works and assigns to him, along with Sir Christopher Wren and Wallis, the distinguished epithet of hujus aetatis geometrarum facile principes.
Huygens was the first to construct powerful telescopes and in 1655 discovered the ring of Saturn and the fourth satellite of that planet. In 1659 he published an account of these discoveries in a work entitled Systema Saturnium. In the end of this work is described an invention of great importance in astronomy, viz., the micrometer (q.v.), by which small angles between objects viewed by a telescope are accurately measured.
In 1660 Huygens visited England, where he was admitted a member of the Royal Society. Huygens was the originator of the wave theory of light; and his theory, now accepted, was first stated by him in 1678, in his Traité de la lumière (first printed in 1690; modern German translation in Ostwald's Klassiker No. 20, Leipzig). In this theory light is conceived to be a form of motion in the medium through which it passes. (See LIGHT.) Later (1690) he was able to explain both reflection and refraction by wave motion in the ether and was also able to account for double refraction. To Huygens is due the discovery of polarization-a phenomenon which could not then be explained by the undulatory theory and led Newton to adopt the emission theory. Huygens was in error, however, in believing that the vibrations were longitudinal rather than transverse. The undulatory theory, however, did not gain general acceptance until the nineteenth century, when the experiments of Young and Fresnel placed it on a firm basis.
A new edition of Huygens's collected works has been published by the Holland Academy of Sciences in 10 volumes (The Hague, 1888-1905) . For his biography, consult P. Harting, Christian Huygens in zijn Leven en Werken geschetzt (Groningen, 1868) , and Bosscha, Christian Huygens, German translation by Engelmann (Leipzig, 1895).
The New International Encyclopaedia, Vol. XI (New York: Dodd, Mead & Co., 1920) 640.