That of Ceres 

 proves to be 

 i6i,6 miles : 



12£ ON TWO CELESTIAL 'BODIES. 



of obfervation, were, for Ceres, about trtj 20° 4', 15° 20'; 

 and for Pallas, T)£ 23° 40', 17° 30', With thefedata, I have 

 calculated the diftances of the ftars from the earth at the time 

 of obfervation, partly by the ufual method, and, where the ele- 

 ments were wanting, by a graphical procefs, which is fuffi- 

 ciently accurate for our purpofe. My computed diftances were 

 1,634 for Ceres, and 1,8333 for Pallas ; and, by them we find, 

 that the diameter of Coxes, at the mean diftance of the earth 

 from the fun, would fubtend an angle of 0",35 1 27 ; and that, 

 confequently, its real diameter is 161,6 miles. 



It alfo follows, that Pallas would be feen, at the fame dif- 

 tance from the fun, under an angle of 0^,3 199 ; and that its 



aivi that of Pallas ^ ea ^ diameter, if the largeft meafure be taken, is 147 miles; 



147 or no| but, if we take the mod diftinct obfervation, which gives the 

 fmalleft meafure, the angle under which it would be feen from 

 the fun, will be only 0",2399 ; and its diameter, no more than 

 llOj miles. 



Of Satellites. 

 Examination for After what has juft now been (hewn, with regard to the 

 fize of thefe new ftars, there can be no great reafon to ex- 

 pect that they fliould have any fatellites. The little quantity 

 of matter they contain, would hardly be adequate to the re- 

 tention of a fecondary body ; but, as I have made many ob- 

 fervations with a view to afcertain this point, it will not be 

 amifs to relate them. 



Feb. 25. 20-feet reflector. There is no fmall ftar near 

 Ceres, that could be fuppofed to be a fatellite. 



Feb. 28. There is no fmall ftar within 3 or 4 minutes of 

 Ceres, that might be taken for a fatellite. 



March 4. 9 h . 45'. ficlereal time. A very fmall ftar, fouth- 

 preceding Ceres, may be a fatellite. See Plate V. Fig. I. 

 where C is Ceres, S the fuppofed fatellite, abcdef, are de- 

 lineation ftars, c and d are very fmall. S makes nearly a 

 right angle with them ; e is larger than either c or d» There 

 is an extremely faint ftar/, between e and d. 



14 h . 16'. Ceres has left the fuppofed fatellite behind. 



March 5. There are two very fmall ftars, which maybe 

 fatellites; fee Fig. 2. where they are marked, lft S, 2d S. 

 The reft, as before, are delineation ftars. 



March 6. The two fuppofed fatellites of laft night remain 

 in their fituation, Ceres having left them far behind. 



lO 



discovering 

 Satellites. 



None were 

 afcertained. 



