8vo. Engraved title vignette, woodcut diagrams in text. (Light spotting to preliminaries.) Contemporary vellum, smooth spine gilt in 5 compartments, gilt-lettering in 2. Provenance: Nicolay Mari (ownership signature in an early hand on title-page).

FIRST EDITION. Clairaut was a member of the French expedition to Lapland (led by P.-L.Moreau de Maupertius) to measure the length of a degree of latitude near the North Pole. His most famous work, Theorie de la figure de la terre, is "to some degree the theoretical epilogue to the Lapland expedition and to the series of polemics on the earth's shape -- an oblate ellipsoid, according to Newton and Huygens, and a prolate ellipsoid, according to Cassini" (DSB). Bibliotheca Mechanica p.72; Graesse II:190; Poggendorff I:447.