271 Fre;/ch Xaiional Instiiufe. 



ot the nieiiibcrs oF the class, we arc indebted for the only 

 observation which succeeded. The cluiuis opened an instant 

 for iiim onlv, and permitted him to see the beginning, which 

 he observed at 4'' 52' 43". He was also able to measure 

 three phaiej, the accuracv of which, however, he does not 

 warrant. 



Tlie atmospheric variations which hindered us from seeing- 

 tht eclipse, were also unfavourable for the observation of the 

 solstice; but as the latter may be supplied by observations 

 made on the davs which precede and follow, we have col- 

 lected a sufticiently great number of thcin together, in order 

 to find a coniirmation of what we have observed for these 

 ten years past. 



M. Bouvard, a pui/d worthy of such masters as Messier 

 and Mcchain, has discovered two comets, and calculated 

 their orbits.. Messrs. liiot and Arrago have made these 

 same calculations by the method of M. Laplace. M. Le- 

 gendrc has not omitted this opportunity of submitting to 

 new trials the formula he published last year. We may 

 justly remark, that there is scarcely any method which does 

 not become inconvenient, or even uncertain, under parti- 

 cular circumstances. This is precisely what h.nppencd thi;? 

 time to M. Lcgendre ; but he immediately found in his ana- 

 lysis resources to obviate the difficulty, which had not been 

 foreseen in his first memoir, and to simplify considerably 

 the general solution which he had given of the problem. 



M. Lcgcndrc is now occupied on a more important ques- 

 tion, alihough the applications of it are more rare: his 

 nieuioir is ( nlitled " Analijsh of Triangles described on the 

 S[)fitrcj/d." 



The first astronomers who measured the earth with any 

 accuracv considered it as a sphere, the radius of which is 

 innnense in comparison of the small intervals which they 

 proposed to ascertain. The largest side of the triangle which 

 enters into these operations is never 60,000 metres, aijd the 

 diH'erenoe between such an arc and the right line, which joins 

 the extremities, is scarcely two decimetres, or a three-hun- 

 dred- millionth part. We mav therefore consider, with great 

 reason, triangles whose curvature is so little, as rectilineal. 



In 



