450 D'ALEMBERT. 



It is equally clear that no comparison can be insti- 

 tuted between him and that most illustrious of the 

 human race. The ' Principia ' stands at an immeasur- 

 able distance before the * Dynamique ;' and the Calcu- 

 lus of Partial Differences is but an improvement, 

 though a very great one, of the Method of Fluxions ; 

 while the optical discoveries of Newton have so little 

 that can be compared with them in the history we are 

 contemplating, that D'Alembert never could bring him- 

 self to take an interest at all in experimental philoso- 

 phy, much less to make any discoveries for extending 

 its bounds. Not only was he without any pretension 

 of this kind, but he was incapacitated from such pur- 

 suits by his entire ignorance of many branches of phy- 



1 1 1 1 1 



sical science, an ignorance almost general with mm on 

 everything which did not lend itself to geometry or 

 rather analysis, an ignorance, be it further observed, 

 extremely discreditable to his understanding as a philo- 

 sopher. Who can read without astonishment his 

 avowal that he knows nothing of chemistry; an avowal 

 borne out by some of his writings, and by the Dis- 

 course to the l Encyclopedic ; ' when we reflect at the 

 same time that the greatest of geometricians and analysts 

 did not disdain to be as thoroughly acquainted with 

 the chemistry of his age, as any one who knew nothing 

 else? Indeed some of his most wonderful conjectures 

 respecting the constituent parts of bodies, may be re- 

 ferred as much to chemical as to optical science.* 



D'Alembert's reason for undervaluing the truths of 

 inductive philosophy, must be allowed to have been 

 wholly unworthy of his genius for general speculation. 

 He thought .meanly of the evidence on which it rests, 

 and could take no interest in any investigations other 

 than analytical. Can any one doubt that the evidence 

 of experiments is in the highest degree deserving of 

 our respectful attention, without refusing also his ap- 



^ * See especially the Queries to the ' Optics.' I remember Dr. Bhek 

 citing these wonderful productions with unbounded admiration. 



