A HISTORY OF SCIENCE 



From 1665 to 1681, accepting the tempting offer 

 made him through Colbert, by Louis XIV., Huygens 

 pursued his studies at the Bibliotheque du Roi as a 

 resident of France. Here he published his Horolo- 

 gium Os dilator ium, dedicated to the king, containing, 

 among other things, his solution of the problem of the 

 "centre of oscillation." This in itself was an impor- 

 tant step in the history of mechanics. Assuming as 

 true that the centre of gravity of any number of inter- 

 dependent bodies cannot rise higher than the point 

 from which it falls, he reached correct conclusions as 

 to the general principle of the conservation of vis viva, 

 although he did not actually prove his conclusions. 

 This was the first attempt to deal with the dynamics 

 of a system. In this work, also, was the true deter- 

 mination of the relation between the length of a pen- 

 dulum and the time of its oscillation. 



In 1 68 1 he returned to Holland, influenced, it is be- 

 lieved, by the attitude that was being taken in France 

 against his religion. Here he continued his investiga- 

 tions, built his immense telescopes, and, among other 

 things, discovered " polarization," which is recorded in 

 Traite de la Lumiere, published at Leyden in 1690. 

 Five years later he died, bequeathing his manuscripts 

 to the University of Leyden. It is interesting to note 

 that he never accepted Newton's theory of gravitation 

 as a universal property of matter. 



