La Condamine embarked for Peru in 1735 with the purpose of measuring several degrees of meridian at the equator to settle the controversy between the Newtonians and the Cartesians over whether the earth was flattened or elongated at the poles. The geodetic measurements proved the validity of Newton's hypothesis, completely debunking the opposing theory by Cassini and Picard. La Condamine's notable zenith sector is illustrated on one of the plates and is described in the text. There is also an account his important research on the pendulum. The complete work is composed of three parts – this being he Premier Part (or first part of 3), first edition. 4to VIII, 266pp, index. Engraved vignette on title and three engraved plates at rear, folding.

References: Sabin 38479 & 38483.

Condition: B

Full leather binding, chipped and worn. Gold embossed spine with raised bands. Front joint split. Bookplate of Harvard Library stamp on title verso. Lightly toned.