Voyages along meridian lines in Europe

• Autores: Suzanne Débarbat
• Localización: The Circulation of Science and Technology: Proceedings of the 4th International Conference of the European Society for the History of Science. Barcelona, 18-20 November 2010 / coord. por Antoni M. Roca Rosell, 2012, ISBN 978-84-9965-108-8, págs. 302-307
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • After the creation of the Paris Observatory meridian line, in 1667, Picard made measurements along it from Amiens to La Ferté-Alais. After his death (1682), Cassini enlarged it in 1683 up to Bourges, later (1700-01), with Cassini II, up to the Pyrenees. The end came only in 1718 from the northern to the southern borders. After measurements in Lapland (1736-37), a new campaign is performed in France by Lacaille around 1740. This may explain why this peculiar meridian was chosen in 1791 to give birth to “une mesure révolutionnaire: le metre”, whose definitive length was fixed, after new measurements (1792-98), in 1799. Other voyages along a meridian line occurred in Europe (1800-20) in Lapland, Spain, Great Britain and in Central Europe (1816-55) with the longest meridian arc ever measured. Despite these new measurements, the length of the “metre” has never been changed, leading 50 years ago to adopt its modern realization for the “Système international d'unités”, the SI, in 1960.