Essential Information

Royal Observatory

16 Nov 2013

A few days ago, Simon, Becky and were guests of the Université de Lorraine for a conference organized by Martina Schiavon and Laurent Rollet on 'Le Bureau des longitudes (1795-1930): contexte national et international'. The meeting was inspired by a project that is going to digitize the minutes of the Bureau des Longitudes and current plans for a larger research project on the history of the Bureau - more news if that gets the go-ahead. Focusing (largely) on the French organization that was set up at the end of the 18th century and which is still going today, the conference gave us a great chance to think about some of our project's work in an international context and about comparisons and contrasts between the English and French bodies. As several speakers mentioned, the motion put forward by Abbé Grégoire in 1795 to create the Bureau des Longitudes made the rather florid claim that Britain's naval power stemmed from its support of astronomy, the Longitude Act of 1714 and the developments that followed under the guidance of the Board of Longitude. Grégoire's rhetoric was overblown, to be sure, but the idea went through the national assembly without any difficulty. While having many similar functions to the Board of Longitude, such as taking responsibility for the production of astronomical tables (specifically the Connaissance des Temps, which in fact predated the Nautical Almanac), there were many ways in which the new Bureau was quite different. For a start, it was put in charge of the Observatoire de Paris and then of the Observatoire de Marseille. Another very different function was the popularisation of astronomy, of which Francois Arago would become the great exponent in the nineteenth century, later being rather wonderfully described, Colette Le Lay informed us, as 'la personification de la science attirante et expansive'. Among other things, Arago's efforts influenced the writings of Jules Verne. We also heard about work in Portugal and the Netherlands in the same period, where astronomical tables for navigators took their data from the British Nautical Almanac and reworked them for a different meridian (Lisbon and Tenerife respectively). In Coimbra, however, a new set of ephemerides, based solely on observations made at the new observatory there, was produced from 1803. This initiative was under the guidance of José Monteiro da Rocha, a Jesuit who had previously written a substantial manuscript on finding longitude at sea in the 1760s, while he was in Brazil, yet clearly aware of the latest news and texts on the subject, including the most recent trials of John Harrison's sea-watch. One of the issues we have been discussing for some time now is the extent to which lunar distances were used by seamen in the late-18th century. In France, Guy Boistel assured us, it was very little, and not at all on merchant ships. Karel Davids, on the other hand, produced some data from the examination of mates on Dutch naval vessels in 1808, which showed that over half of those who claimed to have some knowledge of the technique were able to demonstrate that they were skilled in it. In the same period, he added, chronometers were very rare on Dutch vessels. The papers and conversations ranged over far more than this, as a planned publication will reveal. For those interested, these were the talks: Guy Boistel (Centre François Viète), 'Exploration des archives du Bureau des longitudes - Du (presque) bénévolat à la professionnalisation : l'évolution du statut des calculateurs de la Connaissance des Temps, 1795-1914' Jean-Marie Feurtet (Montpellier), 'L'observatoire de Marseille, succursale du Bureau des longitudes (1790-1850)' Colette Le Lay (Centre François Viète), 'Le Bureau des longitudes et la diffusion de l'astronomie (1795-1880)' Fernando B. Figueiredo (University of Coimbra), 'Les longitudes et les Éphémérides Astronomiques de l'Observatoire Astronomique Royale de l'Université de Coimbra (pendant la période de 1803 et 1845)' Karel Davids (Vrije Universiteit Amsterdam), 'Jacob Florijn and the Longitude Committee (1787-1818)' Suzanne Débarbat (Observatoire de Paris - Bureau des longitudes), 'Le Bureau des longitudes, institution pérenne depuis 1795' Nicole Capitaine (Laboratoire Syrte - Observatoire de Paris – Bureau des longitudes), 'Le Bureau des longitudes en 2013: activités, missions et projets' Simon Schaffer, 'Newton and the Longitude' Rebekah Higgitt, 'French influence: the Board, the Bureau and the 1818 Longitude Act' and me with an overview of the digitization project we launched in July and some thoughts about how one could use it to make links with the Bureau des Longitudes and its work.