| SKETCH OF HUYGENS. |
NO name in the history of science is associated with more material advance, or with advances in more various directions, than that of Huygens. To him we owe important improvements in the telescope, which in his time was a very crude instrument; the discovery of the first satellite of Saturn and of the nature of his ring; the accepted theory of the character of the surface of the moon; the undulatory theory of light, which had to wait till our day to be verified or even accepted; the theory of the pendulum and of the properties of the cycloidal curve; continuous fractions; with Newton, the determination of the shape of the earth; the knowledge of the properties of double refraction and polarization; many other discoveries of practical use or theoretical value; and a few ingenious speculations which have been used to lend attraction to some works of popular science.
Christian Huygens van Zuylichem was born at the Hague, April 14, 1629, and died June 8, 1695. He was the second son of Constantine Huygens, secretary and counselor of three successive Princes of Orange, who was also a distinguished Dutch poet and writer of Latin verses. His grandfather, too, was a secretary to the great William the Silent; and his elder brother Constantine, serving in the corresponding capacity, accompanied Prince William Henry to England, where he went, in 1688, to become King William III.
His earlier instruction was attended to by his father, who, remarking, the signs of promise in him, taught him music, arithmetic, and geometry, and, when thirteen years old, mechanics. At fifteen, he was given an instructor in mathematics; at sixteen, he was sent to Leyden to study law under Vinnius; and he attended the University at Breda from 1646 to 1648. In these cities he enjoyed the instructions of the skilled geometricians, François Schooten and Jean Pell, and his first essays in that branch of mathematics were so fortunate as to attract the attention of Descartes, who wrote concerning it: "A little while ago Professor Schooten sent me a tract by the second son of M. de Zuylichem, touching a mathematical invention which he had sought out; yet he did not find in it what he was looking for (and this was not strange, for he was seeking what no one has ever yet found); but he went at it so straightway that I am sure he will become excellent in that science, in which I hardly ever see any one who knows anything." Huygens also had unbounded admiration for the great philosopher, but never enjoyed the privilege of meeting him.
The prediction of Descartes was very speedily fulfilled, for, within a few years after his graduation, having taken a short journey with Henry, Count of Nassau, Huygens began the series of labors and publications that have made his name immortal, with his theorems, in
