The French Bureau des longitudes (1795-1932): Historical project, Work in progress.

International audienceCreated in 1795 to solve the problem of the computation of the difference of longitude on sea and to manage the Parisian astronomical Observatory, the French Bureau des longitudes has evolved and it still exists (23, quai de Conti, Paris). It has played a leading role in the organization and the development of astronomy and celestial mechanics, in the adoption of the metrical decimal system, in the definition and the realization of time scales, in the emission and transmission of time signals, in the development of earth physics, dynamical geodesy, manufacturing of precision instruments…indeed, the Bureau des longitudes has not been studied yet as a whole institution and on a long time. In this talk, I will firstly present a work in progress on the preservation of a patrimonial and historical archival source: the minutes of the Bureau des longitudes actually being digitized. Secondarily, I will speak about an historical work currently in progress focused on the institutional study of the French board in an international context over a long period (1795-1932)