In his Recherches sur differents points importants du systeme du monde (1754-1756) he perfected the solution of the problem of the perturbations of the planets, which he had presented to the academy some years before.
One of them, Potier, bishop of Beauvais, already gave himself airs as prime minister, but Mazarin had had the address to touch both the queen's heart by his Spanish gallantry and her desire for her son's glory by his skilful policy abroad, and he found himself able easily to overthrow the clique of Importants, as they were called.
Barral, in 17 vols., 8vo, 1854-1862; also separately his Astronomie populaire, in 4 vols.; Notices biographiques, in 3 vols.; Notices scientifiques, in 5 vols.; Voyages scientifiques, in 1 vol.; M*moires scientifiques, in 2 vols.; Melanges, in 1 vol.; and Tables analytiques et documents importants (with portrait), in 1 vol.