48 



movement of light, considered in its utmost generality. Unfortu- 

 nately, this haste in production did not leave him patience to bring 

 his works to maturity. Each new way that presented itself to his 

 mind occupied him exclusively ; and in order to follow it he quitted 

 that which he had begun to explore, even without taking time to see 

 to what it would lead. For the sake of proceeding more rapidly, 

 he almost always condensed his new researches in an unusual nota- 

 tion, which rendered them unintelligible to everybody but himself; 

 and often he did not discover that these innovations only disguised 

 under some strange form results already known. 



In 1840 a place in the Bureau des Longitudes became vacant by 

 the death of Poisson. The members of this body are renewed by 

 election, subject to the approbation of the Chief of the State. 

 Cauchy was unanimously elected, but declined to take the oath of 

 allegiance to the government of Louis Philippe, consequently his 

 election was not ratified. In 1843 Cauchy was commissioned 

 by the Academy to verify the determination of an inequality of 

 long period in the planetary motions. M. Leverrier announced 

 the discovery, in the motion of the planet Pallas having a period 

 of 795 years. Its maximum effect upon the longitude of Pallas 

 exceeds 15', according to the calculations of M. Leverrier. For 

 want of a direct analytical method, he had determined its amount 

 by an extremely bold numerical interpolation which required an 

 immense amount of calculation. In order to avoid the trouble 

 of verifying it, Cauchy invented a direct analytical method, by which 

 all inequalities of this kind can be determined in every case. He 

 obtained the same coefficient as that found by M. Leverrier, and 

 from that time, in problems of this kind, the power of abstract 

 science replaced individual exertion. In 1848 Cauchy resumed the 

 Mathematical Professorship in the Faculte des Sciences de Paris, 

 the only one of his former posts which remained unoccupied. In 

 1851 Cauchy resigned this Professorship for the second time, but 

 soon afterwards, the Minister of Public Instruction, M, Fortoul, easily 

 obtained permission from the Emperor for Cauchy to resume his 

 Chair unfettered by any condition or political test. He expressed 

 his gratitude for this indulgence by devoting the whole of the income 

 he received from the Faculte des Sciences to charitable purposes in 

 the little Commune of Sceaux, where he resided. Once, when the 



