The archives are an important part of the collections with invaluable documents on the history of science in France and throughout the world.
For instance, they include the astronomical archives, from all over Europe, that were once assembled by Joseph-Nicolas Delisle, an astronomer during the 18th century. In the archives, it can be found notably, the correspondence of the Polish astronomer Hevelius (1611-1687), the observation notes taken by Cassini, starting with the very first observations by Jean-Dominique Cassini in 1669, that consisted of drawings of the lunar spots based on observations, and were made by the great draughtsmen Sébastien Leclerc and Jean Patigny. The archival collections also holds the manuscripts relating to the metric system, as well earlier documents that uncovers the first European astrometric satellite, Hipparcos.
Sketch by Japet, the first satellite of Saturn discovered by Cassini on November 6th 1671
In the early days of its foundation, the astronomers of the Observatoire realized the importance of keeping archives, and preserving them carefully. They were entrusted to the Library, which was created in 1785.
A
review established in 1791 lists essentially the original records of observations made at the Observatoire royal de Paris from 1671 until 1791. The documents are key materials for astronomers, historians and even meteorologists. Some of the archives consist of records’ copies from the second half of the 18th century. In 1795, the Observatoire acquired an exceptional collection of scientific manuscripts, collected by the astronomer Joseph-Nicolas Delisle.
Joseph-Nicolas Delisle’s Collections (1688-1768)
Joseph-Nicolas Delisle’s collections (1688-1768) represent a spectacular expansion of the archives : the astronomer acquired many scientific papers during his travels in Germany and Russia, and had also copies made from manuscripts which he was unable to purchase. His correspondence is an integral part of his collection : from 1709 to 1767. Delisle maintained written contact with major astronomers of his time, and his correspondences became an excellent reference on astronomical observations made around Europe. When he returned to France in 1747, Delisle exchanged his collections in return for a lifelong pension and the title of Marine Astronomer. His books and manuscripts were thus acquired by the Dépôt de la Marine in 1750.
In 1795, the Comité de Salut public declared that Delisle’s collection, which had an astronomical interest (books and manuscripts) should be handed over to the Bureau des Longitudes, an institution created the same year to govern the Observatoire.
Le Bureau des longitudes : The Beginnings
The collection isn’t limited to Delisle’s manuscripts, but other items were added as gifts from the members of the Bureau des Longitudes. Additionally, the items that were given by Cassini IV are particularly important. On the 26th of March 1822, he handed over to Delambre fifteen volumes of calculations and works relating to the "Histoire céleste", i.e. the catalogue of the 48 000 stars made by Lalande nephew. On the 8th of January 1823, he wrote to the « Messieurs les membres du Bureau des longitudes » (the "honorable members of the Bueau des longitudes") to present them with a set of manuscripts which he considered to be even more valuable, those collected by his family. There are some remarkable items, such as the "Atlas des taches de la Lune" (Atlas of lunar spots" which contains 57 pencil and red chalk drawings made by Jean Patigny (av. 1632-1679) followed by Sébastien Le Clerc (1637-1714) « sous les yeux et d’après les observations » (in front of and based on the observations) of Cassini I, drawings which were subsequently used to create the famous Carte de la Lune (Map of the Moon). There is also an outstanding set of manuscripts concerning astronomical observations made all over the world, Chinese astronomical tables, original letters, various notes and writings by Cassini I ; there are also documents about the recent history of the Observatoire, as for example those concerning the 1785 reform. Lalande’s « nephew » (in fact his first cousin) contributed to the Bibliothèque royale’s 14 registers of astronomical observations, which were given to the Observatoire in 1840.
The Bureau des longitudes understood the importance of scientific and institutional archives. In the month of February 1823, the Bureau decided to preserve the minutes of all letters sent to the authorities, and two years later, the old lodgings which were on the East side of the meridian, were transformed into an archive, located above a meeting room.
Increasingly Rich and Well Organized Archives
During the 1840s, the archives fell victim to Guglielmo Libri’s theft (1803 ?-1869). As he was appointed Inspector of Libraries in France, during his inspection missions, he began steeling many manuscripts and books from public libraries. At the Observatoire, over 570 items were stolen from the Hevelius correspondence, which had about 2700 items in total. Following this event, Ludovic Lalanne did a first inventory of the archives in 1851, which however was only handed over to the Observatoire in 1879. The only collections’ description was a summary and incomplete catalogue dating back from 1854. Nevertheless, a certain number of stolen items were returned during the 19th century, notably with the help of the Bibliothèque nationale.
From the beginning of his mandate in 1878, Admiral Mouchez promoted a policy for the enrichment of the heritage ; the archives as well as the Museum, were the beneficiaries of this policy. The Observatoire obtained the manuscript of the 3rd edition of Laplace’s Système du monde de Laplace, Lalande’s manuscripts relating to the 1769 solar transit of Venus , as well as Arago’s and Le Verrier’s manuscripts, which were given by their families. Other gifts included, in 1883, the manuscripted observations of the astronomer Honoré Flaugergues (1755-1835), spanning the period 1782 to 1830, the manuscripts of the astronomer Yvon-Villarceau (1813-1883), as well as the correspondence between the Baron de Zach and J.J. Lalande (1792-1804). This new influx was the occasion for the preparation of a new catalogue, the Inventaire général et sommaire des manuscrits de la Bibliothèque de l’Observatoire de Paris, published by Guillaume Bigourdan in 1895.
The Inventaire général et sommaire was continued in 1921 with the creation of a new numerical sequence, starting at 1001 ; between 1922 and 1925, a review of the
Delisle collection of archives led to the creation of an alphabetic index.
During the 20th century, the most important additions came from the archive records of the directors and presidents of the Observatoire, or scientists’ documents (the Bernard Lyot collection, the Evry Schatzmann collection). An important transfer, the archives of the Bureau des longitudes, was made in the opening years of the 1980s. The tradition of gifts has not entirely disappeared. For example, in 2008, the European Space Agency offered to the Observatoire, the archives relating to the astrometric satellite HIPPARCOS, launched in 1989.
Over 50% of the archive material is now inventoried and is accessible via the Alidade tool. Moreover, the Library has now joined the Calames network implemented by l’ABES , and the archive collections will soon be listed there.