78 M. Damoiseau 07i the remarkable Cornet 



round nebulosity, whose position he fixed by estimation. On 

 the day following he was convinced that he had discovered a 

 comet whose nucleus had advanced since the night before a 

 degree to the east, and appeared to have increased in lustre and 

 magnitude. He compared the comet with the star, No. 28 of 

 Bode's Catalogue, to determine its position. He observed it 

 also on the 3d and the 1 2th March. 



M. Gambard discovered this comet at Marseilles on the 9th 

 March, and continued to observe it on the following days. 

 The news of this discovery having spread, the comet was ob- 

 served on the 10th March at Gottingen by M. Harding, at 

 Altona by M. Clausen, and successively in all the observa- 

 tories of Europe, and in the beginning of May it disappeared. 

 By calculating the first observations on the hypothesis of a 

 parabolic orbit, it was evident that the elements of the new 

 comet had a great resemblance to those of 1772 and 1806. 

 The hypothesis, however, of this being the same comet, de- 

 viated greatly from observation, as it might have been expect- 

 ed to do ; but MM. Clausen and Gambard, after some trials, 

 have found, without any communication, an ellipse which re- 

 presents the observation with such accuracy as to leave no 

 doubt of the perfect identity of the three comets. 



M. Damoiseau first gives the ellipse of M. Clausen com- 

 puted from M. Biela's observations of the 28th February, M. 

 Harding's observations of the 14th March, and M. Clausen's 

 of the 28th March. He next gives two ellipses calculated by 

 M. Gambard, the one for 1826, and the other for 1806. 



He then shows that the difference of some days which ex- 

 ists between the observations and the calculations is explained 

 by the changes upon the motion of the comet by the action of 

 Jupiter, who passed very near it in 1782 and 1799. 



This identity being admitted, it is necessary, previous to 

 announcing the next return of the comet, to take into account 

 the perturbations due to the action of the planet in the inter- 

 val between its passage of the perihelion from 1806 to 1826, 

 and in the interval between its last passage and that of 1832, 

 a year which will be remarkable by the reappearance of two 

 comets with elliptical orbits and short periods, viz. that of 

 Encke and that of Biela. 



