ANNIVERSARY ADDRESS. 15 



demanding extraordinary genius, and beside which his astronomical 

 discoveries, for which he is more popularly celebrated, fade into 

 insignificance. 



Rene Descartes 1 [1596 -1650] distinguished alike as a meta- 

 physician and mathematician, published in 1637 his new geometry; 

 in which the application of algebra to geometry, though not novel, 

 became a fruitful conception. As illustrating the power of the 

 new method it may be said that the whole theory of the conic 

 sections of Apollonius is implicitly contained in a single equation 

 of the second degree ! 



To Holland belongs the credit of producing the first formal 

 treatise on probability, with Christiaan Huygens [1629 - 1695] for 

 author. In his 'Traite de la Lumiere' written in 1678, he developed 

 with great skill Robert Hooke's wave theory of light, establishing 

 it upon a sure foundation. His great work ' De horologio oscilla- 

 torio ' ranks second only to Newton's ' Principia.' 



Passing Huygen's and Wallis' 2 quadratures of the circle, Lord 

 Brouncker's 3 investigation of Wallis' expressions, leading him to 

 the theory of continuous fractions, and Isaac Barrow, 4 whose 

 method of tangents differs only from the differential calculus in 

 notation, we come to Newton [1642 - 1727], the Archimedes of 

 the modern world. Newton's great work, the 'Principia,' has 

 been called by Brewster " the brightest page in the records of 

 human reason." Laplace's testimony is scarcely less enthusiastic, 

 when he says that the merits of the Principia will insure to it " a 

 lasting preeminence over all other productions of the human 

 mind." 



Newton's development of the infinitesimal calculus, his concep- 

 tion and exposition of universal gravitation, and the genius with 

 which he illumined natural philosophy, not only constitute his 

 appearance a new era in that domain, but also mark him out as a 

 unique figure in the intellectual history of mankind. 



1 Essais Philosophiques. Leyden. 



2 [1616 - 1703]. 3 [1620 - 1684]. * 1630 - 1677]. 



