Beschreibung:

MÉCHAIN, Pierre François André (1744-1804) and Jean Baptiste Joseph DELAMBRE (1749-1822). Base du Système Mètrique Décimal, ou Mesure de l'Arc du Méridien compris entre les Parallèles de Dunkerque et Barcelone . Paris: Baudouin, 1806, 1807, and 1810. [ In uniform binding with :] BIOT, Jean-Baptiste (1774-1862) and François ARAGO (1786-1853). Recueil d'Observations Géodésiques . Paris: Courcier, 1821. First edition of the foundation work of the metric system, a rare set in uniform contemporary bindings, and complete with the fourth volume published more than a decade after the first three. In 1790, at the request of Talleyrand, the Académie des Sciences set up a commission to consider the problem of finding a fundamental unit of measurement to replace the various diverse regional systems that had been in use throughout Europe for centuries. The members of the commission included J.C. Borda, Lagrange, Laplace, G. Monge and Condorcet. 'In 1791 they reported that the fundamental unit of length should be derived from a dimension of the earth: it should be the ten-millionth part of a quadrant of the earth's meridian extending between Dunkirk and Barcelona... The Constituent Assembly set up a general commission of weights and measures to carry these proposals into effect and in 1795 a law was passed introducing the metric system into France with provisional standards' (PMM). The astronomers Delambre and Méchain were appointed to make accurate measurements of the meridian passing through Dunkirk and Barcelona, and their measurements were completed in 1799. The project had numerous delays, including France's political revolution, the tedious calculations in converting one system to another, and the death of Méchain in 1804. Delambre completed the final volume of their report in 1810. The rarely found supplementary volume records the results of Biot and Arago’s measurements of the arc of the meridian south to the Balearic Islands of Mallorca, Menorca and Ibiza, which the Bureau des Longitudes had commissioned in order to determine the metre’s length more accurately. Alder, The Measure of All Things , 2002; Norman 1481 (lacking half-titles); PMM 260 (3 vols). Together 4 volumes, quarto (242 x 196mm). Half-titles. 30 engraved folding plates and numerous tables in the text (occasional light spotting, one plate trimmed close just into plate mark). Uniform contemporary half tree calf over marbled-paper covered boards, red and green morocco gilt spine labels (extremities lightly rubbed, head- and tailcaps sometime expertly repaired). Provenance : I.R. Istituto Geografico Militaire (stamps on titles).