[132] “C’est que je viens d’un pays où, quand on parle, on est pendu.”
[133] Longevity has been a remarkable characteristic of the great mathematical astronomers: Newton died in his 85th year; Euler, Lagrange, and Laplace lived to be more than 75, and D’Alembert was almost 66 at his death.
[134] This body, which is primarily literary, has to be distinguished from the much less famous Paris Academy of Sciences, constantly referred to (often simply as the Academy) in this chapter and the preceding.
[135] E.g. Mélanges de Philosophie, de l’Histoire, et de Littérature; Éléments de Philosophie; Sur la Destruction des Jésuites.
[136] I.e. he assumed a law of attraction represented by μ∕r2 + ν∕r3.
[137] This appendix is memorable as giving for the first time the method of variation of parameters which Lagrange afterwards developed and used with such success.
[138] That of the distinguished American astronomer Dr. G. W. Hill (chapter XIII., [§ 286]).
[139] They give about ·78 for the mass of Venus compared to that of the earth.
[140] The orbit might be a parabola or hyperbola, though this does not occur in the case of any known planet.
[141] On the Calculus of Variations.