3^0 French National LiJJltute. 



to a flar of (he fcventh or eighth magnitude, it exhibited 

 none of thole appearances that ierve to diliinguifh comets. 

 In colour it relemblcd Jupiter; and, from obfervations made 

 in the meridian by M. Piazzi and his affiitant M. Caccia- 

 tore, it would feem that this ftar is a planet, the orbit of 

 which gives rcafon to fuppofe that its revolution is performed 

 in four years and a half, or five years. Towards the end of 

 riuv'tofe, as this ftar paffed the meridian too earlv, it cealed to 

 be viiiblc ; andlSI. Piazzi, aflifted by Cacciatore and Cariotti, 

 both endowed witli excellent light, and well acquainted with 

 the heavens, endeavoured to find it, but in vain, both with 

 a night-glafs and an achromatic telefcope of a large aper- 

 ture. It needs therefore excite no furprilc that, nine months 

 after, all the aftronomers of Europe (liould have failed in their 

 refearches, fince to the difficulty of the thing itfelf there was 

 added an uncertaintvoffome degrees rei"pec:ling the exa6l place 

 where it was necelfary to fearch for this Itar, as the ele- 

 ments of its orbit, calculated on too' fmall an arc, cannot, 

 after fo long an interval, give, in a fufficiently correft man- 

 ner, the geocentric places. Befides, the heavens have been 

 almoft always cloudy ; and to be able to hope for fuccefs, it 

 would be necelVaryj conlidering the fmall fize of this ftar, to 

 make a correal enumeration of all the ftars from the feventh 

 to the ninth masnitude in the neighbourhood of which it 

 mav appear, and to repeat the examination of them every day 

 until the fmall planet fliould dilcover itfelf by its motion. It 

 will foon be under the fame circumftances in wliich it was at 

 the time of its difeovcrv ; and if the heavens Ihould become 

 more ferene, we may ftill retain feme hope. 



IVwter Soljlice of the year jo. (Dec. 180T.) — The wea- 

 ther, fo unfavourable to the refearches made to obferve Pi- 

 szzi's planet, was no lefs fo to the determination of the fol- 

 Ititial altitude of the fun, which was conttantly concealed 

 from the 19th to the 26th of December; that is to fay, dur- 

 incf thofe davs on which the moft conclufive obfervations 

 eould have been made. However, by collefting thofe made 

 on the precciling and following days, C. Delambre was able 

 to form nine fcries of zenith diftances, obferved by Rorda's 

 circle, which gave him for mean refult an apparent obliquity 

 of 2^^ 28' 3". This quantity holds nearly a mean place be- 

 tween thole found feveral years ago by the winter foHtices on 

 the one hand, and the fummer foUtices on the other. On this 

 occafion the obiervation made at the winter folftice ap- 

 proached very near that made at the fummer foKtice. It is 

 well known, that for a long time paft all aftronomers who 

 have employed themlelves in determining the obliquity of the 

 ecli^nic have always found feveral fegonds lefa in winter 



than 



