LALANDE, Joseph Jerome Lefrançais de, a most zealous and accomplished astronomer, born at Bourg en Bresse, on the 11th of July 1732, was the son of Peter Lefrançais, and Marianne Mouchinet, his wife.

His parents were in easy circumstances, and his education being somewhat too indulgent, the natural quickness and impetuosity of his temper was too little restrained. His earliest taste, like that of most other children, seems to have been for romantic tales; and he was fond of making little stories with such materials as he possessed, but their subject was chiefly religious. He was in the habit of living much with the Jesuits, and he imbibed from them a predilection for the pulpit. At the age of ten he used to amuse himself with making sermons, and preaching them to a select congregation. The comet of 1744, however, with its long tail, took more forcible possession of his imagination, and he watched it with the most unremitting attention. Having been sent to Lyons to continue his studies under the Jesuits there, he acquired a taste for poetry and eloquence, and was then inclined to devote himself to literature and to the bar; but an eclipse of the sun recalled his attention to astronomy. His parents wished him to follow the profession of magistrate, and with that view sent him to Paris; but he accidentally lodged in a hotel where Delislc had established an observatory, and this circumstance led him to become acquainted with that professor, and to attend his lectures. These lectures were by no means popular; and the want of a more numerous audience made it easy for the professor to accommodate his instructions to the fixed attention and rapid progress of his new pupil, who became singularly attached to his master, and to all the methods which he employed. Lalande attended, however, at the same time, the physicomathematical lectures of Lemonnier, who was more in credit as a teacher, and who also took great pains for his improvement.

In the mean time he had completed his legal studies, and at the age of eighteen he was called to the bar as an advocate. His family was anxious for his return to Bourg; but just at that time Lemonnier obtained leave to nominate him as a substitute for himself on an astronomical mission to Berlin, where he was to make observations on the lunar parallax, corresponding with those which Lacaille was sent to the Cape to obtain. He was favourably received by Maupertuis, who introduced him to Frederic and his court; and was made a member of the Academy of Sciences at Berlin, when he was about nineteen.

He remained a year in that city, observing at night, and passing his mornings in the study of the integral calculus, under Euler’s directions; and his evenings in the society of Voltaire, Maupertuis, D’Argens, and other men of talents. It was not likely that his intercourse with such persons would confirm the principles which he had imbibed from the Jesuits; his moral conduct, however, does not appear to have been influenced by his change of sentiments. After his return to Bourg, he pleaded a few causes to oblige his friends; but the success of his operations at Berlin obtained him speedily a place in the Academy of Sciences at Paris; for, in 1753, before he was twenty-one, he was chosen to fill up a vacancy in the department of astronomy, which had been open for some years. He soon afterwards offended his friend Lemonnier, by rejecting too harshly an unfounded objection of that astronomer to his method of computing the effect of the earth’s ellipticity on the lunar parallax, which differed from Euler’s formula. Lacaille, wĥo drew up the report of a committee appointed on the occasion, decided in Lalande’s favour; but Lemon,nier remained dissatisfied, and would not see him for twenty years. He had some similar discussions, at a later period, with Duséjour, who was a little too severe in criticizing some of his approximations, as if they had been intended to be rigidly accurate; but their personal friendship remained unaltered.

For more than fifty years he continued to be a constant and voluminous contributor to the Memoirs of the Parisian Academy, as well as to other scientific collections. His investigations were always judiciously directed to the advancement of astronomy; but they can scarcely ever be said to have exhibited any marked features of talent, or of address, beyond what might be expected from the industry of a man of good ordinary abilities, confining himself almost entirely to one subject. He was always anxious to call the public attention to astronomy as a science, and to himself as an individual. Thus, on occasion of the [7:13:28]transits of Venus in 1761 and 1769, he addressed a circular letter to most of the governments of Europe, on the importance of obtaining a multiplicity of collateral observations; and he received in reply several invitations from sovereigns whose countries were more favourably situated for the purpose than France, to come and make the observations in person. He thought it unnecessary, however, to leave Paris on the occasion. He contented himself with being the first to announce to the public the result of the most satisfactory comparisons; and his countrymen seemed to give him almost the whole credit of every thing that had been done by others in conformity with his suggestions. He was much mortified, however, in not receiving from Father Hell an account of the observations made at Wardhus; and he was afterwards greatly inclined to dispute their accuracy, because Hell made the parallax smaller than he did by ⅜th of a second; whilst the mean of both results, which is 8, 6", agrees extremely well with the most modern computations; but, in the end, he did justice to the importance of Hell’s observations.

He was constantly in the habit of passing a few months every year with his family in the country, and he occasionally amused himself, in the course of these visits, with mineralogical excursions, and with chemical studies. He delivered, about the year 1758, an oration before a public assembly at Lyons, on the advantage of monarchy above every other form of government; he even adhered to a similar opinion, and expressed it openly, in times when nothing but his celebrity, as a man devoted exclusively to science, could have made it safe for him to declare it.

After having published the astronomical tables of Halley, he felt the necessity of a new collection, and determined to begin with those of Mercury, which he found the most imperfect. He pursued, for this purpose, a regular course of observations at the Palais Royal, where he used to go before sunrise, in the winter mornings, to see the planet in the twilight. Having occasion to refer to the observations recorded by Ptolemy, he found it 'necessary to refresh his acquaintance with the Greek language, which he had in some measure neglected. But, with all his labour and diligence, his tables of Mercury exhibited, in 1786, an error of forty minutes in the time of a transit. The circumstance mortified him extremely; but it led to a revision of the tables, and he afterwards succeeded in making them much more perfect. It must be recollected, that, in the time of Hevelius, a transit was anxiously expected for four whole days before it occurred.

He next undertook to improve the tables of Mars and Venus. His tables of these planets were, on the whole, less accurate than those of Mercury, though more exempt from great occasional errors. He had computed their perturbations in the Memoirs of the Academy, but he never thought it worth while to compare his formulas with observation. The irregularities of Jupiter and Saturn were much more discouraging; he was obliged to confine himself, in discussing them, to the most modern observations; and he did not appear sufficiently to appreciate the empirical equations of Lambert, though they greatly diminished the errors of Halley’s tables.

When Maraldi had given up the management of the Connaissance des Tems, Lalande and Pingré were candidates for the appointment. Lalande succeeded in obtaining it; but he had the modesty to confess that the work would have been more accurately performed by Pingré, if his connection with the church had not, according to the rules of the academy, incapacitated him for the situation. He made the work, however, much more popular, as a miscellaneous publication, than Pingre was likely to have done; and he was less prejudiced than Pingré in the choice of his tables. He remained editor of the work from 1760 to 1775; it was conducted by Jeaurat from 1776 to 1787, and from 1788 to 1793 by Méchain. Lalande then undertook it once more, Méchain being engaged in some measurements with Delambre, and the academy having been abolished, and its members dispersed.

Lalande had been disposed to call in question the assertion of Newton and of Voltaire, that no cometcould possibly come into contact with the earth; and he had proved that the effect of perturbations at least rendered their reasonings somewhat inconclusive. A short memoir on the subject, which was to have been read at a public sitting of the academy, was accidentally omitted, as not very important, from the pressure of other business. This circumstance alarmed the sensibility of the public of Paris, who fancied that Lalande had foretold some dreadful catastrophe, which the government was afraid to announce; and when the memoir was published, they insisted that its contents had been modified, to lessen the alarm. Duséjour made some objections to the author’s reasoning; but the whole affair was soon forgotten.

A memoir on the length of the year was honoured with a prize by the academy at Copenhagen. Delambre, however, thinks the determination not so good as the earlier one of Lacaille, though much better than Mayer’s, which was more commonly adopted. Lalande took great pains also with the subject of the sun’s rotation, employing in his computations of the places of the spots an easy approximation, instead of Duséjour’s more laborious methods; but being careful to compare with each other the most distant observations of the same spot. From the existence of this rotation he thought it reasonable to infer that the sun had also most probably a progressive motion, which would naturally be produced by any single impulse capable of occasioning a rotation. He had some discussions with Dr Maskelyne respecting the mode of computing the equation of time, in which Maskelyne appears to have had the advantage.

In the year 1762, Delisle resigned in his favour the professorship of astronomy in the College de France, which he kept for nearly forty-six years. He allowed the most attentive of his pupils to board with him at a cheap rate, doing his utmost on all occasions to promote their success in their studies and in life. Thus he brought forward Méchain and Dagelet, and afterwards his own nephew, who completed, with so much diligence and accuracy, the Description of the Heavens, which he had himself projected, and which had been begun by Dagelet before his unfortunate expedition. He was made a fellow of the Royal Society of London in 1763.

His health was generally good, though his constitution was delicate. He had an attack of jaundice in 1767, which was attributed to intense application; but he completely recovered from its effects by an attention to diet, and by the use of horse exercise. He then intended to leave all his property to the academy; but he afterwards gave up his family estates to his relations, and lived on his appointments only, refraining from all kinds of luxuries, in order to be the more able to do acts of liberality to his friends, whom he always sought to oblige in the most delicate manner, and often without making his services known. He had a pension from Russia in the time of the Empress Catherine; it was suspended by Paul, but restored in 1805 by Alexander.

He was not particularly successful as an observer, but used to refer to the works of his contemporaries, Bradley and Lacaille, though not exactly, according to the expression of one of bis biographers, “as Ptolemy had done to those of Hipparchus ;” for Hipparchus must have been dead two centuries before Ptolemy was born. On the occasion of the disappearance of the ring of Saturn in 1774, he went to Béziers, in order to profit by the superior serenity of the air there, the climate of that country [7:13:29]being supposed to be the best in France; but his observations were less valuable than others made at Paris and in London.

In the year 1798, he undertook an astronomical expedition to Gotha. He had once meditated an aerostatical voyage there; but his companion took care that their dangers should terminate in the Bois de Boulogne. He was received with much interest at Gotha by an assembly of astronomers that was collected from different parts of Germany. The object of the congress was perhaps not unmixed with personal vanity; but it had no political design to promote, unless the general adoption of the new French measures could be considered as a political object. Lalande was by no means a revolutionist; he was sufficiently free from any prejudices of education; but he openly condemned the political opinions of the day; and, in 1792, he even exposed himself to great personal danger in order to save the life of Dupont de Nemours, after the 10th of August; and he was equally useful to some of the clergy, whom he concealed in the buildings of the Observatory at Mazarin College, making them pass for astronomers. He had also the courage to publish accounts of Lavoisier and Bailly, a short time after their deaths.

The attentions of the German astronomers gave him sincere pleasure. He was at all times extremely sensible to compliments, and even to flattery, though very regardless of satire. He used to call himself a sponge for praise, and an oil-cloth for censure. He professedly believed himself endowed with all the virtues, modesty not excepted. He was so fond of notoriety that he once undertook to exhibit the variations of the light of Algol to the public of Paris on the Pont Neuf; but the police interfered, thinking it right to prevent a disorderly assemblage.

Though Lalande can only be classed in the second rank as an inventive astronomer, or a mathematician, he certainly stands in the first as a professor and a popular writer. His methods of calculation have in most instances been already superseded by others more convenient or more exact; those which related to particular phenomena for want of sufficient precision, and those which were more general for want of being readily applicable, without continual repetition, to a sufficient number of concurring observations. It has been observed, that he may perhaps have been often too zealous in the pursuit of his favourite objects; but that, if he had possessed more circumspection, and less vivacity of character, he would have been more exempt from criticism, yet would have rendered less important services to science and to mankind.

His last illness was of a consumptive nature, and he seems to have accelerated its termination by attempting too much to harden himself. He died on the 4th of April 1807, nearly seventy-five years old, and in the perfect possession of his faculties. His last words, when he dismissed his attendants to rest, were, “I have need of nothing more,” and in a few minutes he was dead. Had he survived a few hours, he would have received a letter from Dr Others, announcing the discovery of a new planet, for which that distinguished astronomer afterwards received the fourth prize medal upon the institution founded by Lalande in 1802, for the most important astronomical discovery made in the course of the year.

Of his voluminous and diversified publications a simple enumeration of the subjects will perhaps be thought too long for perusal, though not improper for insertion in a work which ought to comprehend a complete literary history or bibliography of the sciences.

1. We find, in the Memoirs of the Parisian Academy of Sciences for 1751, an account of his Observations at Berlin, which also appears in the Memoirs of Berlin for 1749, and a Latin translation in the Acta Eruditorum for August 1752. 2, 3. 1752-53, An Essay on the Lunar Parallax. 4. 1754,' A Transit of Mercury. 5. Elements of Mars. 6. 1755, Longitude of Berlin. 7. Lunar Eclipse. 8. 1756, Transit of Mercury. 9. Lunar Parallax continued. 10. 1757, Observations at the Luxembourg. 11. Transit of Venus. 12. Secular Equations and Mean Motions. 13. A Gnomonical Problem. 14. Meridian Altitudes. 15. 1758, Perturbations of Mars by Jupiter. 16. Motions of the Planetary Nodes. 17. Change of Latitudes of the Stars. 18. 1759, Comet of 1682 and 1759. 19. 1760, Sun’s Diameter. 20. Perturbation of Venus by the Earth. 21. Eclipse of 1760. 22. 1761, Solar Parallax. 23. Interpolation. 24. Transit of Venus Observed. 25. Solar Parallax. 26. Transit Computed. 27. Observed at Tobolsk. 28. In Denmark. 29. Compasses, and the Variation. 30. Perturbation of Mars by the Earth. 31. Planetary Nodes. 32. 1762, Equation of Time. 33. Obliquity of the Ecliptic. 34. Horary Motion in Transits. 35. Nodes of Jupiter’s Satellites. 36. Diameter of Venus. 37. Comet of 1762. 38. 1763, Eclipses of Jupiter’s Satellites. 39. Solar Eclipses for a Spheroid. 40. Triangles, Rectilinear and Spherical. 4L 1764, Transit of 1769. 42. Lunar Libration. 43. 1765, Motion of Saturn. 44. Eclipses of Jupiter’s Satellites. 45. The Third Satellite. 46, 47. 1766, Theory of Mercury. 50. 1768, Opposition of Jupiter. 51. Transit of 1769. 52. Orbit of Saturn. 53. 1769, Lunar Observations. 54. Comet of 1769. 55. Transit of Venus. 56. A Solar Eclipse. 57. Transit of Venus. 58, 59, 60. Comparisons of Observations. 61. 1770, Solar Parallax. 62. Sun’s Diameter. 63. Appearances in the Transit. 64. Chappe’s Observation. 65. 1771, Theory of Mercury. 66. Astronomical Observations. 67. Solar Parallax. 68. 1772, Transit of Venus. 69. Tides. 70. 1773, Comets. 71. Saturn’s Ring. 72. 1774, An Opposition of Saturn. 73. Saturn’s Ring. 74. Disappearance of the Ring, at Beziers. 75. 1775, Opposition of Mars. 76. Elements of Mars. 77. Same Latitudes and Longitudes. 78. Opposition of Jupiter and Saturn. 79. An Eclipse of Saturn. 80. 1776, Spots and Rotation of the Sun. 81. 1777, Observations at Paris and Madrid. 82. An Observation of Mercury. 83. Longitude of Padua. 84. The Solar Spots, continued. 85. 1779, Third Satellite of Jupiter. 86. Theory of Venus. 87. Herschel. 88. 1780, Obliquity of the Ecliptic. 89. Precession of the Equinoxes. 90. Fourth Satellite of Jupiter. 91. 1782, Duration of the Year. 92. A Transit of Mercury. 93. 1783, An Eclipse of the Sun. 94. Inclination of the Orbits. 95. 1784, Elements of Jupiter. 96. Ellipticity of the Earth. 97. 1785, Motion of Venus. 98. 1786, Secular Equations of the Sun and Moon. 99. Mass of Venus. 100. Equation of Mars. 101. Mars in Quadrature. 102. Orbit of Saturn. 103. Theory of Mercury, fifth Memoir. 104. Satellites of Jupiter. 105. Fifth of Saturn. 106. 1787, Fernel’s Measurement. 107. Herschel’s. 108. Jupiter’s Third Satellite. 109. Conjunction of Venus. 110. Motion of Saturn. 111. Inclination of Saturn. 112. Answer to Lemonnier, on Lunar Observations. 113. Solar Eclipses of 1787. 114. Eclipse of 1666. 115. Caspian Sea. 116. 1787, Eclipse of 1765. 117. 1788, Eclipses applied to Longitudes. 118. Conjunction of Venus. 119. Lunar Parallax, fourth Memoir. 120. Moon’s Diameter. 121. Jupiter’s Fourth Satellite. 122. Satellites of Saturn. 123. Light of Algol. 124. Height of the Seine. 125. 1789, Epacts. 126. Observations of 8000 Stars, first Part. 127. Motion of Venus. 128. Astronomical Observations. 129. Observation of Mercury. 130. Tides. 131. Catalogue of Stars, second Part. 132. 1790, Disappearance of Saturn’s Ring. 133. Interior of Africa. 134. Mém. Inst. i. 1798, Orbit of Mercury. 135. ii. 1797, Occultations of Aldebaran. 136. Solar Eclipse of 1706. 137. Solar Eclipse of 1748. 138.
[7:13:30]

V. 1803, Zodiac at Strasburg. 139. Eclipses calculated. 140. Opposition of Mars. 141, 142. Motion of Venus. 143. Motion of Mercury. 144. vi. 1806, A Transit of Mercury.

145. The earliest of his separate publications appear to have been two little volumes, intended for provincial circulation only, entitled Etrennes Historiques, 24. ∙ Par. 1755-56. 146. Another little article of his miscellaneous works was a Discours qui a remporté le Prix de l’Academie de Marseille en 1757, Mars. 1757. The subject was the spirit of justice, as tending to the glory and the stability of a government. 147. We have then Three Letters on Platina, Jour, des Sav. 1758, Jan. Jun. 1760, Feb. 148. Letter on a new Sun Dial, Jour. Sax. Jun. 1758, ii. 439; the lines being invisible when the sun does not shine.

149. Tables Astronomiques de Halley, 2 vols. 8. Paris, 1759. Containing several new tables, and an elaborate history of the comet of 1759, of which the author had computed the perturbations, according to the theory of Clairaut. 150. Connaissance des Terns, 16 vols. 8vo, Par. 1760-1775; 14 vols. 1794-1807. This work contains, besides, the Ephemeris, an important selection of the most useful astronomical papers. On one occasion, for temporary reasons, these papers were published in a separate volume. 151. Exposition du Calcul Astronomique, 8. Paris, 1762; a companion to the almanac.

152. Oraison funèbre de Maurice Comte de Saxe, 8. Par. 1760. 153. Art du Papetier, f. Par. 1761. 154. Parcheminier, 1762. 155. Cartonnier, 1764. 156. Cha-moiseur, 1764. 157. Tanneur, 1764. 158. Mégissier,

1765. 159. Maroquinier, 1766. 160. Hengroyeur, 1766. 161. Corroyeur, 1767.

163. Letter on Delisle’s Calculations, Jowm. Sav. Apr. 1761. 164-5. In the 52d volume of the Philosophical Transactions for 1761 and 1762, we find several papers of Lalande; two on the transit of Venus; 166. one on Norwood’s Measurement of the Earth; 167. An Account of a Comet; and, 168. An Account of Occultations of the Fixed Stars by the Moon. 169. In the Transactions for 1769, another paper on the Transit of Venus.

170. Discours sur la Douceur, 1763. This essay was intended as a sort of exercise for the author’s own moral improvement; and he made it a rule to read it over every year, in order to assist him in commanding his temper. He may possibly have derived some little advantage from the practice, but he never acquired enough of self-command to refrain from wounding the feelings of another, by any pointed remark that might suddenly occur to him.

171. Astronomie, 2 v. 4. Paris, 1764; 3 v. 1771, 1792; vol. iv. 1780, not reprinted. This compilation far excelled in utility all former works of the kind, and will always be considered as exhibiting the most perfect picture of the science, such as it existed from 1760 to 1790, with all the details of practice and computation. Lemonnier called it, with some truth, the great newspaper of astronomy. The Treatise on the Tides, which constitutes the fourth volume, is chiefly a collection of observations, not sufficient even for the basis of a complete theory: an abstract of it may be found in the Mém. Acad. Dijon, ii. 1774. 172. Figure du Passage de Venus de 1769, Paris, 1764; together with an explanatory memoir. 173. On the Equation of Time, Recueil pour les Astronomes, 1765.

174. He undertook the mathematical department of the Journal des Savans, from 1766. 175. On the Coins of Piedmont, Jowm. Sav. Dec. 1767. 176. Voyage d’un François en Italie, 8 vols. 12mo: a correct guide and faithful repertory for travellers, containing some scientific information, besides maps of the principal cities. 177. Dissertation sur la Cause de l’Elévation des Liqueurs dans les

Tubes capillaires, 8. Par. 1770. 178. A Dictionary of Astronomy, in the Encyclopedic d’Yverdun, 56 v. 4. 1770-6. 179. Abrégé d’Astronomie, 8. Par. 1773, 1795; translated into various languages. 180. Notes on the Mondes Primitifs of Fontenelle, 24. Paris; often reprinted. 181. Notes on Bouguer’s Traité de Navigation. 182. Mémoire sur le Passage de Venus, 4. Par. 1773; with a life of Dr Bevis. 183. Reflexions sur les Comètes qui peuvent approcher de la terre, 8. Par. 1773. 184. Lettre à Cassini sur l’Anneau de Saturne, 8. Toulouse, 1773; a violent attack, which was speedily suppressed by the author. 185. Ephemerides, 3 vols. vii. viii. ix. Paris, 1774, 1792. This was a continuation of Lacaille’s computations, containing also some detached articles of importance; for instance, Hampstead’s Catalogue, in the eighth volume. 186. A Celestial twelve-inch Globe, Paris, 1775.

187. The astronomical articles in the Supplement of the Old Encyclopédie, about 1776; those of D’Alembert, in the body of the work, having been little more than extracts from Lemonnier. 188. To the Encyclopédie Méthodique Lalande contributed a Dictionary of Astronomy, making about one third of the Mathématiques, 3 vols. 4to. They were principally extracted from his own astronomy; and the article Cadran, which is very elaborate, was originally intended for a fifth volume of that work.

189. Traité des Cannaux de Navigation, f. Paris, 1778. This volume is principally descriptive, especially of the Canal of Languedoc. 190. Letter on the Variation of the Compass, as connected with the Temperature of the Earth, Journ. Sav. 1780. Sept. 191. Leçons d’Astronomie de Lacaille, 8. Par. 1780; with some Notes. 192. Astronomie, in Dibliotldque des Dames, 12. Par. 1786, 1795.

193. Letter on the name of the planet Herschel, Journ. Sav. 1789; objecting to “Uranus.” 194. Description d’une Machine de Μ. Ramsden, 4. Paris, 1790; the dividing engine, translated. 195. Account of nine Lalandes, Journ. Sαv. Nov. 1791. 196. Journey to Manheim in 1791, Journ. Sav. 1791. 197. On the Zodiac at Strasburg, Journ. Sav. 1791.

198. Abrégé de Navigation, 4. Paris, 1793; with a full catalogue of works relating to the subject, and many useful tables. 199. A Journey to Mont Blanc, performed in 1796, Mag. Encycl. ii. iv. 433. 200. Histoire Celeste Française, i. 4. Par. 1801; containing the catalogue of stars begun by Dagelet, and continued by Michel Lefrançais Lalande, the nephew of the editor. 201. Continuation of Montucla’s Histoire des Mathématiques, 2. v. 4. Par. 1802; making the third and fourth of that elaborate work, but not equally well digested and discussed with the original part. 202. Tables de Logarithmes, 18. Par. 1802. 203. Four Memoirs on Ceres, Journ. Phys. 1802. 204. Some articles in the Nécrologie des Hommes Célèbres. He wrote, at different times, Accounts of the Lives of Vicq d’Azyr, Delisle, Commerson, Verron, Me. Lepaute, and Dubocage; and he had undertaken a life of Bucholz, a short time before he died. Commerson had complimented him by making a genus Lalandia, transgressing in his favour the classical canon of the botanists, to reserve such honours for the reward of merit in their own department.

205. Bibliographie Astronomique, 4. Paris, 1803; with a history of the Progress of Astronomy from 1781 to 1802. This useful volume was printed at the public expense, under the auspices of François de Neufchateau. The author possessed a very extensive collection of astronomical books, and it has been regretted that he did not insert a more complete account of some of the most rare; but the work is already sufficiently voluminous. Some other productions are attributed to him in the Dictionnaire des Anonymes; but they would probably have added little to his fame had they been acknowledged.

(Delambre, Mém. Inst, viii. 1807. H. P. 30; and Biographie[7:13:31] Universelle, xxiii. 8vo, Paris, 1819. Ma. C. de Salm, Magas. Encycl. 1810, ii. p. 288; including a sketch by himself, written in 1804.) (l. l.)