B A I L L Y. 



205 



Baiily. whole aperture of the telescope, and from the interval 

 of time which elapsed, he obtained the values of the 

 diameters of the satellites, which we have given in 

 Astronomy, liable LX. p. 813. 



Baiily had long meditated an extensive work on 

 the history of astronomy, and in the year 1775, he 

 completed the first volume of that profound work, 

 entitled, Histoire de V Astronomie Ancienne. The 

 second and third volumes, entitled, Histoire de V As- 

 tronomie Moderne, appeared in 1779, and the fourth 

 in 1782, which completed the history of ancient and 

 modern astronomy. The return of M. Gentil from 

 India, with a new set of astronomical tables, the 

 epochs of which extend to such a remote period as 

 the year 3102 before Christ, attracted the attention 

 of philosophers to this curious branch of the history 

 of astronomy. These tables were put into the hands 

 of Baiily, who diligently compared them with mo- 

 dern observations, and who found that they must 

 either have been constructed from actual observa- 

 tion, or that the Indians must have been acquainted 

 with the most refined and intricate theories of physi- 

 cal astronomy. The profound researches, the nice 

 calculations, and the ingenious and acute reasonings 

 by which he has supported the antiquity of the In- 

 dian astronomy, were published in 1787, in his Traite 

 de I' Astronomic Indienne ct Orientate, which com- 

 pleted the great work to which his life had been de- 

 voted. * 



The Histoire de V Aslronomieby Baiily, is perhaps 

 one of the most interesting books that has ever been 

 written upon a scientific subject. His ingenious 

 speculations respecting the early history of astrono- 

 my ; the copious brilliancy of his descriptions ; 

 the eloquence with which he pleads the cause, and 

 paints the sufferings of neglected genius ; and 

 the glowing imagery with which his lively fancy 

 every where embellishes the general narrative, throw 

 an air of enchantment round the most common de- 

 tails. Even amid the driest enumeration of facts, the 

 attention is perpetually arrested and kept alive by the 

 nir t delicate touches of nature, and by the nicest 

 discrimination of character. The loose and scatter- 

 ed materials which the history of astronomy often 

 presents, are chained together in one connected 

 narrative, and one astronomer follows another, and 

 new discoveries spring from those which precede 

 them, as if the progress of discovery had been under 

 the controul of causes less accidental than those which 

 nature has prescribed. But it is in those great and 

 general views which constitute the peculiar province 

 of philosophy, that Baiily shines above all praise. In 

 tracing the effects of moral causes and political insti- 

 tutions on the advancement of astronomy, and on the 

 general progress of our species ; in painting the 

 baneful effects of an unholy superstition upon the 

 happiness and improvement of mankind; in describ- 

 ing those alternate periods of languor and renovation, 

 which accompany the mighty convulsions of nations, 

 which follow the tyranny or munificence of princes, 

 or in which the human mind, without any apparent 

 cause, sinks into torpid inactivity, or soars beyond 



its wonted flight ; in marking the connection be- 

 tween the various sciences, and estimating the mutual 

 aid which each imparts to the advancement of the 

 rest ; and in anticipating the conquests which hu- 

 man genius has yet to atchieve over vice and error, 

 throughout every region of Nature Baiily rises to 

 a sublimity of eloquence, which could be inspired 

 only by the powerful interest which he felt for the 

 progress of science, and for the happiness of his fel- 

 low creatures. 



Besides this extensive work, Baiily published the 

 following papers in the Memoirs of the French Aca- 

 demy. " Memoir on the Epochs of the Moon's 

 Motions at the end of the last Century." " On the 

 Comet of 1762." " Astronomical Observations 

 made at Noslon 1764." " On the Eclipse of the 

 Sun of the 1st April 1764." " Observations made 

 at the Louvre, from 1760 to 1764." " On the 

 Cause of the Variation of the Inclination of the Se- 

 cond Satellite of Jupiter." " On the Motion of the 

 Nodes, and on the Variation of the Inclination of Ju- 

 piter's Satellites." " Essay on the Theory of the 

 Satellites of Jupiter." " Observations on the Op- 

 position of the Sun and Jupiter." " On the Equa- 

 tion of Jupiter's Centre," &c. " On the Transit of 

 Venus in 1769, and on the Eclipse of the Sun on the 

 4th June of the same year." 



Like D'Alembert, his illustrious contemporary, 

 Baiily was highly distinguished by his literary at- 

 tainments. His Eloge upon Leibnitz, published in 

 1768, carried off the prize of the Academy of Ber- 

 lin, and the eloges which he composed upon Charles 

 V., Corneille, La Caille, Cook, Moliere, and Gres- 

 set, extended his reputation as an elegant writer. 

 The speculations contained in the first volume of his 

 History of Astronomy, respecting the early state of 

 Upper Asia, led to a correspondence with Voltaire ; 

 the substance of which he afterwards published in 

 two volumes, the first of which was entitled, Lettrcx 

 sur I'Origine des Sciences, ct sur celle des Peuples 

 de I'Asie, Paris, 1777 ; and the second, Lettres sur 

 l' Atlantide de Platon,. et sur V Ancienne Histoire 

 de I'Asie, Paris, 1779. These two works, and the 

 Eloges already mentioned, were published in two vo- 

 lumes in 1770, under the title of " Discourses and 

 Memoirs;" and were reprinted in 1790, along with 

 other discourses of Baiily, that had been pronounced 

 when he was President of the National Assembly, 

 and Mayor of Paris. 



A similarity of opinion with the celebrated Buffon, 

 occasioned such an intimacy between Baiily and 

 that able naturalist, that when the office of secre- 

 tary to the Academy of Sciences became vacant in 

 1771, Baiily offered himself as a candidate, and was 

 supported by all the influence of Buffon. The inte- 

 rest of D'Alembert, however, was powerfully exert- 

 ed in favour of Condorcet, and- Baiily lost his elec- 

 tion. He did not, however, long enjoy the friendship 

 of Buffon. The opposition which he made to the 

 admission of the Abbe Maury into the French Aca- 

 demy, irritated Buffon, and dissolved the friendship 

 which they had mutually cherished. Besides those 



Baiily. 



A general view of the arguments employed by Baiily and ITofcssor Playfair, in defence of the authenticity of the Indian 

 tables, will be found in the history of Asi komomv, p. 58& 



