ON THE NEW PLANETS CERES AND PALLAS. 213 



XVI. 



Duplicate Copy of a Letter from Baron de Zach <o the Right 

 Honourable Sir Joseph Banks, Bart. P. R. S. $c. tranf- 

 mitted to Mr. Edward Troughton, and communicated, 

 by the Rev. J. Pearson; on the new Planets Ceres and Pallas, 

 with the Elements of the Orbit of tlte former. 



Seeberg Obfervatory, near Gotha, May SI, 1802. 

 most honoured sir, 



H.AVING profecuted Dr. Olber's Pallas from April 4 till 

 May 11, in the meridian, Dr. Gauls, upon this let of my ob- 

 fervations, calculated the elements of an eliptical orbit of this 

 very remarkable heavenly body, which reprefent, with great 

 accuracy, all the Seeberg obfervations. 



It appears, in general, by thefe calculations, that Pallas is a Orbit of Pallas 

 planetary heavenly body, that moves between the orbits of Mars and ™g "2" c * 

 Jupiter, with a very great eccentricity and inclination, and zvhofe Hiked in that of 

 orbit comes very near to the orbit of the planet Ceres, perhaps Ceres. 

 touches it, perhaps even cuts it, like two links of a chain, this 

 way 00, which cannot yet be alferted with certainty, the ob- 

 ferved arc run over by this planet being too fmall. Notwith- 

 ilanding, it appears already that the diftances of Pallas and 

 Ceres, in the line of nodes of their orbits, is very nearly equal. 

 In the defcending node, the diftanceof Pallas from the Sun is 

 = 2,86, and the fame diftance of Ceres =2,93. In the 

 afcending node, thefe diitances are of greater inequality. An- Intereftlng re- 

 other very remarkable circumftance is, that the mean motions ""yj^^f t h e 

 of Pallas and Ceres are very nearly, perhaps abfolutely the orbit of Pallas. 

 fame ; though this cannot yet be aflerted, becaufe the error of 

 the obfervations of both planets is (till too great. But as far as 

 yet appears, thefe mean motions will not differ very much ; 

 and in this cafe, fmall as the malfes of Ceres and Pallas may be, 

 they will neverthelefs exert a very fenfible action one upon 

 the other, and therefore give occanon to very curious and in- 

 terefting inveftigations in the mechanics of the heavens. The 

 new planet Pallas will alfo call forth the utmofl exertion of our 

 analytical powers. Hitherto the two elements of a planetary 

 orbit, viz. the eccentricity and the inclination, had been consi- 

 dered as an infinite little quantity, and fo it might be, as thefe 

 4 two 



