i lb DISSERTATION SECOND. [part h. 



ward from the facts to the general principle, and again down 

 from that principle to its effects, both required the applica- 

 tion of a mathematical analysis which was but newly invent- 

 ed ; and Newton had not only the difficulties of the investi- 

 gation to encounter, but the instrument to invent, without 

 which the investigation could not have been conducted. 

 Every one who considers all this, will readily join in the senti- 

 ment with which Bailly closes a eulogy as just as it is elo- 

 quent. Si, comme Platon a pense, il existoit dans la na- 

 ture une. cchelle Metres et de substances intelligentes jus- 

 qiOa PElre Supreme, Pespece humaine, defendant ses droits, 

 auroit unc fmde de grands hommes a presenter , mais New- 

 ton, suivi de ses verites pures, montreroit le plus haut de- 

 gre de force de Pesprit humain, et suffiroit seul pour lui 

 assigner sa vrai place. 1 



Though the creative power of genius was never more 

 clearly evinced than in the discoveries of this great philoso- 

 pher, yet the influence of circumstances, always extensive 

 and irresistible in human affairs, can readily be traced. The 

 condition of knowledge at the time when Newton appeared, 

 was favourable to great exertions ; it was a moment when 

 things might be said to be prepared for a revolution in the ma- 

 thematical and physical sciences. The genius of Copernicus 

 had unfolded the true system of the world ; and Galileo had 

 shown its excellence, and established it by arguments, the 

 force of which were generally acknowledged. Kepler had 

 done still more, having, by an admirable effort of generali- 

 sation, reduced the facts concerning the planetary motions 

 to three general laws. Cassini's observations had also ex- 

 tended the third of these laws to the satellites of Jupiter, 

 showing that the squares of their periodic times were as the 

 cubes of their distances from the centre of the body round 



1 Hist, de VAstron. Mod. Tom. II. 



