MÉCHAIN (Pierre) and Jean-Baptiste DELAMBRE. Base du système - Lot 40

MÉCHAIN (Pierre) and Jean-Baptiste DELAMBRE. Base du système métrique décimal, ou Mesure de l'arc du méridien compris entre les parallèles de Dunkerque et Barcelone, exécutée en 1792 et années suivantes. Paris, Baudouin, Garnery, January 1806; July 1807; November 1810. 3 volumes in-4, blond half-calf, ornate spine, eggplant title and appendix, marbled edges (period binding). Very rare first edition of this important work in the history of the metric system (PMM, no. 260). Decorated with 28 plates, most of them folding. In 1790, Talleyrand called for the unification of weights and measures. After adopting the decimal system, the Academy of Sciences appointed a commission [...] to determine the basis of units of measurement. [...] the commission adopted the quarter of the terrestrial meridian, of which the ten millionth part would be the unit of length. Borda called this unit the meter. Astronomers Delambre and Méchain were commissioned to take precise measurements of the meridian arc between Dunkirk and Barcelona. Their work lasted almost ten years, as they had to overcome enormous difficulties due mainly to the French Revolution (Philippe Zoummeroff in En français dans le texte, n°212). Méchain died in 1804, and it fell to Delambre to complete the calculations and write the book, the first two volumes of which appeared in 1806-1807, and the third a few years later in 1810. A well-bound copy. Some foxing. Joints split across two boxes in volume III, hinges rubbed.