D'ALEMBEKT. 427 



with that illustrious colleague, whom he showed an un- 

 worthy disposition to differ with. A controversy of 

 some length arose between them, when the principles 

 of the solution respecting the lunar orbit were applied 

 to the construction of lunar tables. D'Alembert' s were 

 published in his ' Eecherches' in 1754, and he soon 

 found their inaccuracy to be considerable ; the results 

 of his calculations sometimes differing seven or eight 

 minutes from the observations. He was obliged in 

 1756 to give a corrected set after further investigation. 

 Clairaut was writing at the same time on this subject, 

 and he had received a prize from the Academy of 

 Petersburgh for his work. D'Alembert, who had been 

 a candidate too, attacked his methods in his ' Recher- 

 ches,' 1756, Clairaut gave a criticism of this book 

 and of the author's method in the ' Journal de S9avans;' 

 D'Alembert replied in the * Mercure ;' and Clairaut re- 

 joined in 1758. The same unworthy spirit broke out 

 on Clairaut having applied his investigation of the dis- 

 turbing forces to the comet of 1682, (Halley's comet,) 

 expected in 1759, but appearing a month earlier than 

 Clairaut foretold, owing to an error of nineteen days 

 in the computation. Anonymous attacks upon him he 

 ascribed to D'Alembert, and a long series of controver- 

 sial papers in different journals ensued ; until Clairaut 

 appeared to silence his adversary by an elaborate sum- 

 mary of the dispute, in 1762.* Again, when Clairaut 



* I observe that Montucla (vol. iv. p. 72) considers D'Alembert as the 

 author of the anonymous attacks, but he is evidently prejudiced against 

 him. Indeed it is not clear that the editor, Lalande, may not have modi- 

 fied some passages. A person who could write the note about Clairaut 

 might, indeed, be rather suspected of leaning against him. But there is 

 no being certain respecting one who is so weak as Lalande ; one who, not 

 content with constantly recording his own small exploits in science, prints 

 a motto under his portrait in the edition of Montucla, purporting that 

 though the heavens were under his empire, and his genius penetrated 

 through space, he yet reigned still more in the hearts of men. His flippant 

 note (vol. iv. p. 188), on Boscovich shows his dislike of D'Alembert. "Le 

 Pere Boscovich ne fesait pas autant de calcul integral que D'Alembert, 

 mais il avoit bien autant d'esprit." He charges D'Alembert with perse- 



