SKETCH OF HUYGENS. 835 



SKETCH OF HUYGENS. 



"VTO name in the history of science is associated with more material 

 -L^ advance, or with advances in more various directions, than that 

 of Huygens. To him we owe important improvements in the tele- 

 scope, 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 ac- 

 cepted theory of the character of the surface of the moon ; the undu- 

 latory 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 deter- 

 mination of the shape of the earth ; the knowledge of the properties 

 of double refraction and polarization ; many other discoveries of prac- 

 tical use or theoretical value ; and a few ingenious speculations which 

 have been used to lend attraction to some works of popular science. 



Christiai^ Huygens van Zuyliciiem was born at the Hague, 

 April 14, 1629, and died June 8, 1695. He was the second son of 

 Constantino 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 IH. 



His earlier instruction was attended to by his father, who, remark- 

 ing 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, Franpois Schooten and Jean Pell, and his 

 first essays in that branch of mathematics were so fortunate as to at- 

 tract 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 any- 

 thing." Huygens also had imbounded admiration for the great phi- 

 losopher, 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 pub- 

 lications that have made his name immortal, with his theorems, in 



