CASSINI, Jacques (1677-1756). "De la grandeur et de la figure de la terre." In: Suite des memoires de l'Academie Royal des Sciences. Anne MDCCXVIII. Paris: Imprimerie Royale, 1720 [i.e. 1722]. 4o (242 x 182 mm). 15 folding engraved plates. (Lacking frontispiece and 5 maps, some minor browning and spotting.) Modern calf antique; cloth folding case. FIRST EDITION of the official account of his geodetic survey in which "he confirmeed his support for the hypothesis of the elongation of the terrestrial ellipsoid and oppposed that of its flattening, which was defended by the supporters of Newton and Huygens" (DSB). Norman 412. -- Csar Franois CASSINI DE THURY (1714-1784). La meridienne de l'Observatoire Royal de Paris. Paris: Hippolyte-Louis Guerin and Jacques Guerin, 1744. 4/so (253 x 194 mm). 14 folding engraved plates, including 5 maps. Contemporary mottled calf, spine gilt (joints starting); cloth folding case. Provenance: Joseph Marie Lemoine D'Essoies (1751-1816), mathematician and geographer (large engraved bookplate); Charles Fournerat (inscription on above bookplate: "Ex libris Caroli Fournerat," and his extensive notations on front flyleaf). FIRST EDITION. In this treatise, Cassini de Thury "corrected his father's work to conform to the Newtonian view, using new measurements of the Paris meridan undertaken in 1739-1740" (Norman 413). -- Csar Franois CASSINI DE THURY. Description gomtrique de la France. Paris: J. Ch. Desaint, 1783. Large folding engraved map after Maraldi and Cassini, by d'Heulland (dated 1744). (Some minor browning.) Contemporary mottled calf gilt; cloth folding case. Provenance: "Dhombres" (ink stamp on title). FIRST EDITION of Cassini de Thury's final work, a geometric description of France. The map shows the meridian of the Royal Observatory, its perpendicular, and the principal triangles, constructed on 17 bases. See Tooley, pp. 107 and 418; Norman 414. (3)