364 



B O U G U E R. 



Bouguer. Upon the death of his father in I "713, young JBou- 

 ' ' "v"' ' guer was appointed Professor of Hydrography, and, 

 at the early age of 15, he is said to have discharged 

 the duties of his office with singular reputation. 

 This situation was by no means given to Bouguer, 

 out of respect to the memory of his father. Pro- 

 fessor Aubert, who was charged by the minister 

 with the examination of the young candidate, almost 

 refused to listen to his pretensions, till Bouguer re- 

 minded him that knowledge was not confined to any 

 particular age, and solicited a rigorous examination, 

 during which he exhibited an extent of capacity and 

 information which astonished his examinator. 



In the small town of Croisic, the talents, of Bou- 

 guer were almost buried in oblivion. He aspired to 

 a seat in the Academy of Sciences, without indul- 

 ging the hope of ever reaching the object of his ambi- 

 tion. A trifling accident, however, contributed to 

 extend his fame, and to introduce him on a theatre 

 more suited to the pre-eminence of his talents. Ha- 

 ving accidentally met with the celebrated Reyneau at 

 Angers, the academician soon perceived the strength 

 as well as the direction of his genius, and he conver- 

 sed with him on the different subjects of his studies, 

 but particularly on the masting of ships, a subject 

 which had occupied much of Bouguer's attention. 

 Reyneau took frequent opportunities of mentioning 

 in Paris the researches of Bouguer on the masting of 

 ships, and obtained a reading of the memoir for M. 

 Mairan, who had taken an interest in the young ma- 

 thematician. Mairan had influence enough to get 

 this made the subject of the Academy's prize for 

 1727, which Bouguer, though only in the 29th year 

 of his age, carried off against every competitor. I 

 1729, he received a similar reward for the best 

 method of determining the height of the stars at 

 sea. In his paper on this subject, which was pub- 

 lished separately at Paris, in 1729, under the title of 

 Dela matdere d' observer exaetem entsur mer la hauteur 

 lies Asires, he claims the merit of having been the 

 iirst who determined the path described by a ray of 

 the sun, in its transmission through the earth's at- 

 mosphere j but the solution of this problem had been 

 given long before by our couitryman Dr Taylor. 

 This work was attacked, in 1732, by Meynier, a na- 

 val engineer, who proposed the use of a semicircle, 

 instead of a quadrant, as employed by our author. * 



In the year 1729, Bouguer published his essay on 

 the gradation of light, entitled, Essai d'optique stir 

 la gradation de la lumiere, which was republished by 

 the Abbe de la Caille in 1760. This work is replete 

 with new views, and ingenious experiments, and has 

 been much esteemed by all experimental philosophers. 

 In the year 1730, Bouguer was removed to Havre, 

 and from his proximity to Pans, he formed an inti- 

 mate friendship with several of the members of the 

 Academy of Sciences, who recognized his distin- 

 guished abilities, and obtained for him the office of 

 Associate Geometer, which was vacant by the pro- 

 motion of Maupertuis, in 1731. In the same year 

 he published his prize essay on the best method 

 of observing the variation of the compass; and in 

 1734 appeared his Enlrcticns sur la cause de inclina- 

 tion da orbites des planetes, which was the subject of 



the prize proposed by the Academy for 1732 and 

 1734. The abilities which were displayed in these 

 different works, procured for their author the office 

 of Pensioner Astronomer in 1735, vacant by the 

 death of M. Lietaud, and pointed him out as one of 

 the most proper persons for carrying into execution, 

 the plan which the Academy had meditated, of mea- 

 suring a degree of the meridian in South America. 

 He accordingly embarked at Rochelle, along with Go- 

 din, Condamine, and Jussieu, on the I6thof May 1735, 

 and returned to his native country in June 174 1, af- 

 ter an absence of nine years, during which he not 

 only performed the part which was assigned him by 

 the Academy, but took advantage of his situation 

 among the lofty mountains of the Andes, to make a 

 number of experiments and observations of a very in- 

 teresting nature. The first account of the operations 

 of the three French mathematicians was published at 

 London in 1739, under the title of A relation of the 

 Observations made at Quito on the Miquity of t/ie 

 Ecliptic, by M. Bouguer. These observations had 

 been transmitted to our countryman Dr Halley, 

 who caused them to be printed. In the Memoirs 

 of the Academy for 1744 and 1745, Bouguer him- 

 self gave an account of his labours in America ; but 

 it was not till 1749 that he published his great work 

 entitled, La Figure de. la Terre detcrminee par les ob- 

 servations de M. M. Bouguer el de la Condamine, par 

 M. Bouguer ; which contains his theoretical investi- 

 gations respecting the earth's figure ; and a full ac- 

 count of all the operations that attended the measure- 

 ment of a degree of the meridian in Peru. Condamine, 

 the associate of his labours, was displeasc-d with the 

 pretensions of Bouguer, who seemed to withhold from 

 his fellow-travellers their just share of reputation, and 

 . he asserted his own claims in his Journal Hislorique 

 du Voyage a la Eqiialeur, &c. Bouguer endeavoured 

 to justify his narrative, in a work published in 1752, 

 entitled, Justification des Memoires de V Academic de 

 1744, ct du livrede la figure de la tcrre, sur plusieiirs 

 fails qui concernent les operation des Academiciens. 

 Condamine replied to this pamphlet, in the same year, 

 in his Supplement au Journal Hislorique du Voyage 

 a I'Equateur, et au livre de la mesure des trois pre- 

 miers degrcs du meridicn, pour servir dc reponse aux 

 objections de M. Bouguer ; and he published the se- 

 cond part of it in 1754, in his Lellre dans laquelle on 

 c/iscniediverspointsd'aslronomiepratiquc, et i cmarqttes 

 stir le supplement au Journal du Voyage de M. de la 

 Condamine ; and he was again answered by Conda- 

 mine in a Reponse a la Lellre de M. Bouguer sur 

 divers point de V Astronomic pratique et sur le supple- 

 ment de M. Condamine. 



In this controversy Condamine' seems to have enjoy- 

 ed the greatest share of public suffrage. Bouguer 

 was well known as having a suspicious and jealous 

 temper, and to be more disposed to envy than to exalt 

 the good name of his contemporaries. The mortifica- 

 tion which he felt at the applause given to Condamine, 

 the natural irritability of his temper, and the death of 

 his only brother, to whom he was ardently attached, 

 seem to have had some share in injuring his bodily 

 health, which an incessant application to study had 

 been gradually undermining. He was seized with 



* See the Rnrue.il des Prix, vol. i. for Bouguer's paper, and vol. ii. for that of Meynier. 



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