18 History of Astronomy for the Year 1803. 



October near Apt, in Provence, under similar circumstance?, 

 and which resembles all the others of the same kind *. 



I shall terminate my history by an account of some losses 

 •which astronomy this year has sustained. 



M. Prosperin, one of the ablest astronomers of Sweden,. 

 died on the 28th of March, at the age of sixty-four. He 

 gave a great many calculations of comets and of longitude? 

 deduced from eclipses, which may be seen in the Transac- 

 tions of the Academies of Stockholm and of Upsal. He 

 never published any separate work, but he rendered great 

 service to astronomy by his memoirs. He calculated the 

 comet of 1795f. 



We lost in France, on the 7th of March, the oldest of 

 the astronomers in Europe, esteemed for his long labours, 

 Edme-Sebastian Jeaurat. He was born Sept. 24, 1724; he 

 was the son of an ingenious artist, engraver to the king, 

 and grandson of the celebrated Sebastian Leclerc, of whom 

 we have more than 4000 engravings. 



His uncle Etiennc Jeaurat, who was afterwards painter to 

 the king, taught him early to draw ; and an intimate friend 

 of the family, Lieutaut, astronomer of the academy, in- 

 structed him in the mathematics. He improved under these 

 two masters ; for at the age of twenty-two he obtained a 

 medal for drawing from the Academy of Painting, and in 

 1749 he was employed as a geographical engineer in con- 

 structing the large map of France, 600 square leagues of 

 which he surveyed. In 1750 he published a treatise of per- 

 spective, which has always been of great use to painters in 

 consequence of the clearness of the operations and demon- 

 strations. In 1753 he was professor of mathematics in the 

 military school, the first established provisionally at Vin- 

 cenne, where I had an opportunity of knowing him. 



I engaged him to cooperate in our astronomical labours, 

 for which we were then in want of assistants. Jeaurat ex- 

 erted himself with zeal : he calculated the oppositions of 

 1755 and following years; he observed the comet of 1 7 5 1> 

 and that of 1760; and he gave analytical formulae for cal- 

 culating the motions of the planets. His formulae contain 

 the sixth power of eccentricity, and prove that he possessed 

 great readiness in analysis, which at the time was rarely em- 

 ployed by astronomers. 



The academy published several of his memoirs in the 

 collection Des Savans Etr angers in 1763; and the same 

 year he participated with Bailly in the suffrages of the aca- 



* Sec Moniteur, November 24. 



f Connoissanoe des Temps, an 6, 1798, p. 16. 



demy 



