'French National Injlitntt. Zgf 



of Mercury is onlv 7, and that of the planet Ceres difco- 

 vered in 1801 bv Piazzi, io° 37'. Thus we (hall be obliged 

 to enlarge confiderably the zodiac, if we continue to denote 

 by that name the zone of the heavens in which the planets 

 perform their revolutions. Another very remarkable pecu- 

 liarity is, that the mean diflance of this planet differs very 

 little from that of Ceres. We are not yet acquainted in the 

 folar fyftem with two planets the orbits of which are fo 

 near. 



" So many Angularities render this new planet highly iu- 

 terefting to aflronomers; for it is befides fo fmall, that it can 

 have no fenfible influence on the neighbouring planets: while, 

 on the other hand, it mufi experience very confklerable pertur- 

 bations from Jupiter. C. Burckhardt has kept an account of 

 the principal of them, in order to determine an elliptical orbit. 

 We have indeed great need of a pretty correct theory, to be able 

 to find this planet when it (hall ifTue from the folar rays, into 

 which it is about to enter; otherwife its fmall fize would render 

 the feareh for it very uncertain. It is even highly probable that 

 it would have remained ftill a longtime unknown, had it not 

 been found exactly in the place winch Ceres had quitted, and 

 quite clofe to ftars which had been much obferved by aflro- 

 nomers for fevcral months. It was a curious union, that of 

 three new planets with which aitronomy has been enriched 

 in our days, they were all three feen to pafs the meridian 

 in a few minutes of time. M. Olbers has given to his planet 

 the name of Pallas." 



The perfection to which inftruments and methods are now 

 carried, has enabled aflronomers to deduce from a fmall num- 

 ber of obfervations, the determination of the elements of the 

 planetary orbits, which they were formerly obliged to leave to 

 future ages. One of thefe ftars is no fooner discovered, than 

 its motions are afligned with remarkable precifion, as is 

 proved by the oppofition of Ceres, or Piazzi's planet, ob- 

 ferved at the military fchool by Lalande junior and Burck- 

 hardt. 



They have determined the moment of the oppofition, on 

 the 26th of Ventofe, year 10 (March 17th 1802), at 3 1 ' 46' 

 8'! mean time of the national obfervatory, Paris. 



The true longitude freed from the efYe&s of aberration, 

 nutation and parallax, 176 2i' 26'"$ 



Northern geocentric latitude 17 7 57-5 



The tables conttrueted by C. Burckhardt, differed from 

 obfervation + ^4 in latitude, and + 2i // '8 longitude. The 

 latter of thefe errors indicates that the radius vector mult 

 be a little increafed; but the author ftill waits for new ob- 



U 3 fervations 



