CASSINI DE THURY, César-François (1714-84). La Meridienne de l' Observatoire Royal de Paris, Paris, 1744, 4to, 14 folding engraved plates and maps, contemporary mottled calf gilt (rubbed). FIRST EDITION.

CASSINI DE THURY, César-François (1714-84).  La Meridienne de l' Observatoire Royal de Paris, Vérifiée dans toute l' Etendue du Royaume par de Nouvelles Observations. Pour en Déduire la Vraye Grandeur des Degrés de la Terre, tant en Longitude qu' en Latitude, & pour y Assujettir toutes les Opérations Géométriques faites par ordre du Roi, pour lever une Carte Générale de la France ... Avec des Observations d' Histoire Naturelle, faites dans les Provinces traversées par la Meridienne, par M. Le Monnier ... Suite des Mémoires de l' Académie Royale des Sciences, Année M.DCC.XL. Paris: "Chez Hippolyte-Louis Guerine, & Jacques Guerin," 1744. 4to (254 x 195mm). Half title, text within double-rule border throughout, engraved illustrations, initials and ornaments, 14 folding engraved plates and maps, tables (some light mainly marginal spotting and staining, a few darker spots, very small hole in one plate). Contemporary mottled calf, the spine gilt in compartments with red morocco lettering-piece, red edges, marbled endpapers (head of upper joints split, rubbed and scuffed, stain to head of upper cover). Provenance: Sigurd von Numers (modern signature on the front free endpaper; please see note to lot 304). FIRST EDITION of this work in which the author, having assisted his father Jacques Cassini in measuring the perpendicular to the meridian from Saint-Malo to Strasbourg, supports the view that the earth was flattened rather than elongated at the poles, a conclusion already deduced by Newton from his theory of gravity. Honeyman Collection of Scientific Books and Manuscripts 616; Haskell F. Norman Library of Science and Medicine 413.