Delisle, Joseph-Nicolas

(b. Paris, France, 4 April 1688; d. Paris, 11 September 1768)

astronomy, geography.

The ninth child of the historian-geographer Claude Delisle and Nicole-Charlotte Millet de la Croyère, he became known to his contemporaries as Delisle le cadet or le jeune to distinguish him from his two older brothers. After receiving his early education from his father, he began to develop a taste for mathematics near the end of his formal education in rhetoric at the Collège Mazarin. A solar eclipse in 1706 stimulated this new study and led to instruction in the elements of astronomical calculation under Jacques Lieutaud. He was soon frequenting the Royal Observatory, where he was permitted to copy Jacques Cassini’s unfinished lunar and solar tables. When his first attempt to launch his own observational career in the cupola of the Luxembourg Palace was hampered by a lack of instruments, he turned temporarily to the production of various astronomical tables desired by Cassini.

Having equipped his observatory, Delisle began a regular observational program with the lunar eclipse of 23 January 1712. Forced to abandon his observatory in September 1715—when the Due d’Orleans became regent and installed his eldest daughter, the Duchesse de Berry, in the Luxembourg Palace—he resumed his observations at the end of 1716 in Liouville’s former apartment at the Hôtel de Taranne. After almost four years there he moved his instruments to the Royal Observatory and also had some work done in the Luxembourg Palace dome, which he regained in 1722, after the duchess’ death in 1719.

This early fulfillment of promise carried Delisle into the Academy of Sciences as a student astronomer attached to Maraldi in 1714, and he quickly began what was to be a long series of contributions—primarily reports of observations of eclipses and occultations—to its Mémoires. Since it was also necessary for him to earn a livelihood, he gave mathematics lessons and won a small pension under the regency by drawing up astrological forecasts. An appointment to the chair of mathematics at the Collège Royal in 1718 freed him from such endeavors and also brought him students who aided him in the making and reduction of observations. His best-known students during this period were Godin, Grandjean de Fouchy, and his younger brother, Delisle de la Croyère.

Delisle’s growing reputation brought him, in 1721, an offer from Peter the Great to found an observatory and an associated school of astronomy in Russia, an invitation which was transformed into mutually acceptable contractual arrangements in 1725. Planned for four years, Delisle’s stay in Russia lasted twenty-two years. There he created an observatory which came to enjoy a good reputation while training many astronomers—with elementary treatises in the preparation of which Delisle participated. Some of these students, as well as his younger brother and the instrument maker who had accompanied him, subsequently engaged in geodetic and cartographic ventures throughout the country, the results of which they communicated to him for a projected, but unrealized, large-scale and accurate map of Russia. To provide corresponding observations for longitude determinations, Delisle published his St. Petersburg observations of eclipses of Jupiter’s satellites in each of the first six volumes of the Commentarii of Russia’s Imperial Academy of Sciences.

Various physical and meteorological data came to him as well, some of the latter inspired by a “universal thermometer” invented and widely distributed by Delisle. He described this device in a work published in 1738, which also contained his and his brother’s numerous observations of aurora borealis in Russia and a record of his own early Paris observations and experiments on light. Furthermore, Delisle returned to an interest in transits of Mercury first manifested in 1723, when he had considered, but failed to demonstrate, that the technique suggested in Halley’s famous 1716 paper on the use of transits of Venus to determine the parallax of the sun could be equally utilized in the more frequent transits of Mercury. He now treated this possibility for the 1743 transit of Mercury in a letter to Cassini, which the latter placed in the Mémoires of the Paris Academy of Sciences.

That institution took cognizance of the length of Delisle’s absence by naming him to veteran status in 1741. This did not change with his return to Paris in 1747, although he resumed attendance at the Academy’s meetings. He also returned to his Luxembourg Palace observatory to witness a solar eclipse of July 1748, about which he had prepared an avertissement to alert astronomers. In addition he regained his chair at the Collège Royal; most notable among his students in this latter period was Lalande.

One of Delisle’s long-standing activities had been the amassing of vast amounts of geographical and astronomical material through an extraordinarily extensive correspondence, through inheritance, and through laborious copying. Because of its great value the French government purchased this collection by giving Delisle the title of astronome de la marine and a life annuity of 3,000 livres. Moreover, he obtained a new observatory at the Hôtel de Cluny. It was there, in 1759, that his pupil and assistant, Charles Messier, observed the return of Halley’s comet. The place of its reappearance had been the subject of a paper by Delisle in 1757.

In other late works Delisle made some use of his meteorological and cartographic materials from Russia and devoted some attention to longitude determinations. The latter had a significance for transit studies because his perfection of Halley’s technique by a simplification of the necessary observations demanded precise longitude information. Having also corrected Halley’s planetary tables, Delisle produced an avertissement on how to observe the 1753 transit of Mercury and a mappemonde showing the favorable stations. He then determined that the Mercury phenomena were inadequate for parallax determination and concentrated his efforts on the forthcoming transit of Venus in 1761, serving as stimulator and coordinator of its worldwide observation by virtue of an other mappemonde and an accompanying memoir distributed through correspondence.

Delisle retired increasingly after this activity. Lalande began to teach in his stead at the Collège Royal in 1761. In 1763 he withdrew to the abbey of ste.-Geneviève to devote himself to charitable and religious works, although he did publish several maps by his eldest brother, Guillaume. Both the Academy of Sciences and the Collège Royal conferred honors upon him prior to his death from an attack of apoplexy in 1768. His wife, whom he had married before his trip to Russia, died shortly after their return; they had no children.

BIBLIOGRAPHY

1. Original Works. Delisle’s immense collection of observations, maps, and correspondence is scattered among several Paris repositories. He provided a partial description of the collection and some autobiographical materials in a MS preserved in the Bibliothèque Nationale: “Histoire abrègèe de ma vie et des mes occupations dans l’ astronomie, la gèographie et la physique, pour servir d’introduction au catalogue de mes manuscrits et mémoires d’ astronomie et de géographie conservés au Dépōt des plans et cartes de la Marine...” MS fr. 9678, fols. 24–31. In 1795 the purely astronomical part of the collection was given to the Bureau des Longitudes and became the basis of the archives of the Paris Observatory. That part includes an abrégé of his unfinished Traité complet d’ astronomie exposée historiquement et demontrée par les observations, Archives de l’Observatoire de Paris, A 7 10, and, besides the materials providing the basis for that work, his own early observational journals, which contain a brief autobiographical note on his astronomical beginnings, C 2 14. Only a small part of his correspondence has been printed: E. Doublet, ed., Correspondence échangée de 1720 à 1739, entre l’astronome J.-N. Delisle et M. de Navarre (Bordeaux, 1910); and H. Omont, ed., Lettres de J.-N. Delisle au comte de Maurepas et à I’abbé Bignon sur ses travaux géographiques en Russie (1726–1730) (Paris, 1919). His contributions to the Mémoires of the Paris Academy of Sciences prior to his departure for Russia were as follows: “Sur l’observation des solstices” (1714), pp. 239–246; “Résultat de l’observation de l’éclipse du soleil du 3 mai 1715 au matin, faite au Luxembourg en présence de Madame la Princesse, de M. le Conite de Clermont et de plusieurs autres seigneurs” (1715), pp. 85–86; “Observation de l’éclipse de Vénus par la lune, faite en plein jour au Luxembourg le 28 juin 1715” (1715), pp. 135–137; “Sur l’atmosphère de la lune” (1715), pp. 147–148; “Observation de l’éclipse de Jupiter et de ses satellites par la lune, faite au Luxembourg le 25 juillet 1715 au matin”(1715), pp. 159–160; “Reflexions sur l’expérience que j’ai rapportée à Académie d’un anneau lumineux sembable àcelui que l’on aper¸oit autour de la lune dans les éclipses totales du soleil” (1715), pp. 166–169; “Observation de l’eclipse de lune du 20 septembre 1717 au soir, faite à Montmartre” (1717), pp. 299–301; “Occultaion d’Aldebaran par la lune, observée le 9 février 1718 au soir, à l’Hōtel de Taranne” (1718), p. 17; “Sur les projections des éclipses sujettes aux parallaxes; où l’on explique la manière dont les astronomer les considèrent, l’usage qu’ils en font, et où l’on donne l’idée d’une nouvelle projection, qui réduit la détermination géométriques de ces éclipses à une expression plus simple que celle qui se tire des projections ordinaires” (1718), pp. 56–67; “Construction facile et exacte du gnomon pour règler une pendule au soleil par le moyen de son passage au méridien” (1719), pp. 54–58; “Observation de l’éclipse d’Aldebaran par la lune, faite à l’Hōtelde Taranne à Paris le 22 avril 1719, au soir” (1719), p. 318; “Observation de l’ećclipse d’Aldebaran par la lune, faite àl’Hōtel de Taranne à Paris, le 30 octobre 1719 au soir” (1719), p. 319; “Détail de l’expérience de la réfraction de l’air dans le vuide” (1719), pp. 330–335; “Sur le dernier passage attendu de Mercure dans le soleil et sur celui de mois de novembre de la présente année 1723” (1723), pp. 105–110; “Observation du passage de Mercure sur le soleil, faite à Paris dans l’Observatoire Royal, le 9 novembre 1723, au soir” (1723), pp. 306–343; “Observations de l’éclipse totale du soleil du 22 mai 1724 au soir, faites à Paris, dans l’Observatoire Royal et au Luxembourg, par MM. Delisle le Cadet et Delisle de la Croyère” (1724), pp. 316–319.

Although some of his observations were reported by himself and others, his only significant contribution to the Mémoires during his absence from Paris was the “Extrait d’une lettre de M. Delisle, écrite de Petersbourg le 24 août 1743, et adressée à M. Cassini, servant de supplément au Mémoire de M. Delisle, inséré dans le volume de 1723, p. 105, pour trouver la parallaxe du soleil par le passage de Mercure dans le disque de cet astre” (1743), pp. 419–428.

His contributions to the Commentarii Academiae imperialis scientiarum petropolitanae were as follows: “Eclipses satellitum Jovis observatae Petropoli,” 1 , 467–474, in collaboration with his brother; “Continuata relatio eclipsium satellitum Jovialium Petropoli,” 2 ,491–494; “Observationes altitudinis poli in Observatorio imperiali, quod Petropoli est, habitae,” 2 , 495–516; “Tertia series observationum satellitum Jovis in Observatorio imperiali Petropoli factarum,” 3 , 425–462; “Continuata relatio eclipsium satellitum Jovis observatarum,” 4 , 317–321; “Eclipsium Jovis satellitum in Observatorio petropolitano observatarum continuatio,”, 5 , 451–457; “Eclipses satellitum Jovis observatae in Imperiali specula astronomica, quae Petropoli est, per integrum annum 1738,” 6 , 395–400; “Observationes astronomicae in specula Academiae imperialis scientiarum ab anno 1739–1745, a Josepho Nicolao Delilio cum sociis institutae,” 6 , 349–362.

Other publications from this period were a three-part Abrégé des mathématiques pour l’usage de Sa Majesté im peńorale de routes les Russies(St. Petersburg, 1728), written in collaboration with Jacques Hermann, to which he contributed the second part dealing with astronomy and geography, a Discours sur cette question: Si l’on peut démontre, par les seuls faits astronomiques, quel est le vrai systeme du monde? et si la terre tourne ou non (St. Petersburg, 1728) which he had read to the Academy, a Projet de la mesurede la terren en Russie (St Petersburg, 1737), and his Mémoires pour servir à l’histoire et au progrè de l’astronomie, de la géographie et de la physique, recueillis de plusieurs dissertations lues dans les assemblées de l’Académie royale des sciences de Paris et de celle de Saint-Petersbourg, qui n’ont point encore éte imprimeés, comme aussi de plusieurs pièces nouvelles, observations et réflexions rassemblées pendant plus de 25 années (St. Petersburg, 1738).

After his return from Russia he placed the following items in the Paris Academy’s Mémoires;” Observation de l’éclipse du soleil du 25 juillet 1748, faite à Paris au Palais du Luxembourg” (1748), pp. 249–254; “Observations du thermomètre, faites pendant les plus grands froids de la Sibérie” (1749), pp. 1–14; “Observation de l’clipse de lune du 23 décembre 1749, faite à Paris dans l’Hōtel de Cluny” (1749), pp. 320–321; “Observation de l’éclipse totale de lune du 13 décembre 1750, au matin, faite à Paris dans l’Hōtel de Cluny” (1750), pp. 343–344; “Mémoire sur la longitude de Louisbourg, dans l’Isle Royale” (1751), pp. 36–39; “Observation pour la conjonction de Jupiter avec la lune, du 29 décembre 1751 au soir, faite à Paris dans l’Hôtel de Cluny” (1751), pp. 90–92; “Observation de l’éclipse de lune du 2 décembre 1751 au soir, faite à Paris dans l’Hōtel de Cluny” (1751), pp. 273–274; “Réponse de M. Delisle [à une lettre de M. Bradley]” (1752), pp. 434–439; “Mémoire sur le diamètre apparent de Mercure, et sur le temps qu’il emploie à cntrer et à sortir du disque du soleil dans les conjonctions inférieures écliptiques” (1753), pp. 243–249; “Observation de l’occulation de l’étoile p du Verseau par la Tune, et de la conjonction de l’étoile, θ avec la mèmeplanète, le 21 novembre 1754 au soir, faites à Paris à l’Hōtel de Cluny” (1754), pp. 382–383; “Détermination de la longitude de l’Isle de Madère, par les éclipses des satellites de Jupiter observées par M. Bory, Lieutenant des Vaisseaux du Roi, comparées avec celles de M. l’abbé de la Caille à l’Isle de France” (1754), pp. 565–571; “Observations des diamètres apparens du soleil, faites à Paris les années 1718 et 1719, avec des lunettes de différentes longueurs; et réflexions sur l’effet de ces lunettes” (1755), pp. 145–171; “Nouvelle théorie des éclipses sujettes aux parallaxes, appliquée à la grande éclipse du soleil qu’on observa le 25 juillet 1748” (1757), pp. 490–515; “Observations du passage de Mercure sur le disque du soleil, le 6 novembre 1756; avec des réflexions qui peuvent servir à perfectionner les calculs de ces passages et les élémens de la théorie de Mercure déduits des observations” (1758), pp. 134–154;“Mémoire sur la comète de 1758” (1759), pp. 154–188; “Mémoire sur la comète de 1759...” (1760), pp. 380–465.

Separately published items of astronomical significance during this later period were his Avertissement aux astronomes sur l’éclipse de soleil du 25 juillet 1748 (Paris, 1748), the Lettre de M. Delisle sur les tables astronomiques de M. Halley (Paris, 1749), the Avertissement aux astronomes sur le passage de Mercure au devant du soleil, qui doit arriver le 6 mai 1753, avec une mappemonde, où l’on voit les nouvelles découvertes faites au nord de la mer du Sud(Paris,1753), and a Recherche du lieu du ciel où la comète, préditepar M. Halley, doit commencer à paraōtre (Paris, 1757).

In the purely geographical realm, he published separately a memoir read to a public assembly of the Academy in 1750 and reported in the Histoire de l’Académie...of that year (1750), pp. 142–152: Explication de la carte des nouvelles découvertes au nord de la mer du Sud (Paris. 1752). His later map publications were noted in Histoire: (1763), pp. 112–117; (1764), pp. 158–160; (1766), pp. 114–122.

II. Secondary Literature. The laudatory “official” éloge for the Academy of Sciences was written by Delisle’s student Grandjean de Fouchy and appeared in Histoire de l’Académie... (1768), 167–183. Equally generous in its praise and somewhat more detailed was Lalande’s “Élog de M. de l’Isle.” in Le nécrologe des hommes célèbres de France, par une société de gens de lettres, V (Paris, 1770), 1–86. The next treatment of him was quite critical: J. B. J. Delambre, Histoire de l’astronomie au dix-huitième siècle (Paris, 1826), pp. 318–327. The rather brief account in J. F. Michaud, ed., Biographie universelle, X, 334–335, is inadequate, as is the more recent treatment in Niels Nielsen, Géomètres franfais du dix-huitième siècle (Paris. 1935), pp. 163–166. The first significant attention to his work in Russia was that paid in Petr Pekarski’s Histoire de l’Académieimpériale des sciences de Petersbourg (Paris, 1870), pp. 124–155. The negotiations preceding that trip were treated by J. Marchand in “Le départ en mission de l’astronome J.-N. Delisle pour la Russie (1721–1726),” in Revue d’histoire diplomatique, 43 (1929), 1–26; his work there and the maps that he brought back are dealt with in detail in Albert Isnard’s “Joseph-Nicolas Delisle, sa biographic et sa collection de cartes géographiques à la Bibliothèque nationale,” in Bulletin de la Section de géographie du Comité des travaux historiques et scientifiques, 30 (1915), 34–164. On the Delisle materials that went to the Paris observatory, see Guillaume Bigourdan, Inventaire général et sommaire des manuscrits de la bibliothèque de l’Observatoire de Paris(Paris, n.d). taken from Annales de l’Observatoire de Paris. Mémoires, 21 (1897), F 1-F60. On his Paris observations and observatories, see Bigourdan’s Histoire de l’astronomie d’observation et des observatorres en France, pt. 2 (Paris, 1930), 20–33, 74–92. On the reputation of the observatory of St. Petersburg under his direction, see Bigourdan’s “Lettres de Léonard Euler, en partie inébites,” in Bulletin astronomique, 34 (1917), 258–319, 35 (1918), 65–96. For brief indications on his teaching at the Collège Royal, see Louis-Amélie Sédillot, Les professeurs de mathématiques et de physique ginérale au Collège de Frame (Rome, 186),^pp. 128–130. Finally, for an excellent analysis of his contribution to the study of transits and the parallax question, see Harry Woolf, The Transits of Venus; A Study of Eighteenth-Century Science (Princeton, 1959), e sp. ch. 2.

Seymour L. Chapin