D'ALEMBEKT. 449 



view of which, we have been occupied, his merits as a 

 man of science and a man of letters. And certainly 

 the difference is very wide between his position in 

 these two different classes ; nor can I avoid marvelling, 

 with Sir J. Mackintosh, at the partiality which so far 

 blinded Mr. Stewart, as to make him consider him very 

 eminent in both. 



Among mathematicians he holds a high place indeed, 

 ranking on the very first line. Euler was perhaps a 

 more fertile analyst ; and he gave incomparably greater 

 contributions to the science, than either D'Alembert or 

 indeed any other man. Clairaut was excelled by none 

 in the profoundness of his researches, and the origi- 

 nality of his methods, and he passed all others in the 

 marvellous precocity of his genius as a geometrician. 

 At the same time, we can never forget that D'Alem- 

 bert's discovery of the dynamical theorem, and his 

 most felicitous employment of it to arrange the whole 

 of mechanical science, exceeds anything accomplished 

 by either of his illustrious contemporaries in usefulness, 

 indeed in originality ; while of a most important cal- 

 culus he was, if not the father, certainly the person 

 who by applying it and teaching its uses, effected a 

 great change in the face of geometrical and physical 

 science. His investigation of the lunar orbit ; of the 

 earth's figure, of the precession and the nutation, would 

 have entitled him to rank with Euler and with Clairaut, 

 and before Fontaine, had his * Dynamique ' and his 

 ' Partial Differences'* never been given to the world. 

 On the latter subject, Euler and Fontaine in some sort 

 anticipated him ; but taking the former discovery into 

 our account, and his application of the calculus, we 

 shall probably be justified in placing him the first 

 among the philosophers and geometricians who suc- 

 ceeded Sir Isaac Newton. 



* It is in his two works on Fluids, and in his Memoirs on the Winds 

 and Vibrating Chords, that we find this method, and rather used or applied 

 than explained. 



2 G 



