€ Remarks on M. Delamlre's [July, 



would have entirely approved of the expression of the author of his 

 life, who describes Euler as holding the sceptre of geometry at the 

 time when Lagrange began his mathematical career. I shall quote 

 likewise some paragraphs from Euler's letters, to show that he was 

 not disposed to arrogate to himself so much superiority over his 

 rival. They were written from Berlin to a French philosopher, in 

 1752, and the succeeding years. 



" M. d'Alembert has a wonderful fertility of invention, as is 

 obvious from every thing that he does. His most important work 

 is his essay on the precession and the nutation ; and that question 

 is one of the most difficult that can be discussed." 



" I feel disgusted with labouring at the theory of the moon, 

 especially since M. d'Alembert has said that he has a particular way 

 of treating the approximations, and of neglecting very little. I 

 wish 1 knew the smallest portion of his method. I would undertake 

 the labour of discovering the whole." 



" I am much obliged to you for the information you have given 

 me respecting the work of d'Alembert on the moon, for the publi- 

 cation of which I wait with the greatest impatience. The more I 

 have examined the difficulties of this subject, the more I am con- 

 vinced that nobody is able to overcome them but M. d'Alembert, 

 whose penetration tills me with as much admiration as esteem."* 



Let us remember that these opinions were given, by so great a 

 man, of him who first gave a general method of reducing all ques- 

 tions about motion to questions about equilibiium ; who discovered 

 the principles of the motion of rotation of solid bodies, and 

 Tigorous equations respecting the motion of fluids ; introduced into 

 mechanical philosophy the calculus of partial diflerencas ; resolved 

 with the necessary rigour the problems of vibrating cords, of the 

 precession of the equinoxes and the nutation; and treated generally 

 the figure of the planets — of him who invented the method of 

 integrating simultaneous equations, and various other contrivances 

 in the integral calculus no less useful than ingenious — of him whose 

 solution of the problem of three bodies is preferred by the illus- 

 trious author of the Mecanique Celeste, and who threw a philoso- 

 phical eye on all the bases of pure and mixed mathematics. If we 

 recall all these true titles of glory, we may satisfy ourselves with 

 laughing at the English journalistf who speaks of d'Alembert as a 

 plagiary ; but for the honour of the nation, we must regret that 

 Frenchmen, speaking of his famous principle of dynamics, have 



* These fragments make us acquainted with the opinion which Elder entertained 

 of d'Alembert as a mathematician. The following shows us what he thought «f 

 him as a maji s— M 1 had the honour of seeing here M. d'Alembert, who showed ine 

 so much friendship that I am filled with gratitude, and should be highly delighted 

 were he lo accept the place of President of our Academy. It would be the only 

 method of doing us honour hero. I (Utter mysrlf that he will be at last induced 

 to yield to our solicitations. At present my eldest son is very well established | 

 h\ the recommendation of M. d'Alembert, the King has given him a pension of 

 ■iz hundred crown.-," &c. Written ill 1163. — .\ott by the Editor of the Mvniteur. 



+ The Quarterly Review. 



