2«0 Memoifi on Dr. Qlhrs' Flantt. 



ing with his telefcope all the fmall liars in the Virgin's- wing* 

 tAVerta'm their portions, that he might he better able To 

 ertablifh the place of the planet, and bad come to the 20th 

 ll<af of the Virgin, near which he had obierved the planet 

 iff the month of .January. 1 le was furprifed to fee near this 

 ftafc, which is of the cth magnitude, another fmaller of the 

 7th magnitude. He was very certain that it had not been 

 tlY^re at the time of his firft obfervations : he therefore haf- 

 tefied to determine its pofition ; and, having continued to 

 view it for two hours, he perceived that it had changed its 

 pirtee in the courfe of that interval. The two following 

 n%h>ts afforded him the means of being certain of its mo- 

 tion, Which was 10 minutes per day. On the a&th of 

 March, at 9 11 25' mean time, at Bremen, it had jSto?Jjf)X 

 right afceniion, and 11* -33/ north declination. 



Aftronomers have been accuftomed to confidcr as comets, 

 all liars that have motion. This was the cafe with the pla- 

 nets of Herfchel and Piazzi at the time when they were iiif- 

 covered. That of Dr. Gibers had no more refemblance to 

 a comet than the reft. With an achromatic telefcope, the 

 magnifying power-of which was j8o, it could not be diftin- 

 gunhed from ftars of the 7th magnitude. It was better de- 

 lined than the planet of Piazzi ; and, with a telefcope of 13 

 feet, whjch magnified 2-8-8 times, it feemed to have a diameter 

 of 4 feconds : but this was an effeci of irradiation, or of the 

 difperfion of the rays of light, which always makes the dia- 

 irteteYs appear too large; for the fatellites of Jupiter appear 

 mud* larger than the new planets, and yet we know that 

 their apparent diameter is not a fecond. 



Dr. Mafkelyne, by means of diaphragms placed before 

 the objecli-glafs of his telefcope, afcertaih'cd that the light of 

 Piazzi's planet is ftronger by one half than that of the new 

 planet. 



Dr. Olbers having obferved the new (lar for four days, he 

 fent notice to different aftronomers ; and on the icth of 

 April, C. Burckhardt, when he received his letter, went im- 

 mediately to the military fchool .to fearch for it, and next day 

 fent his obfervation to the Inftitute. 



He began to calculate its orbit, trying fir ft -a circle, and 

 then the parabola known to 'be that of comets; but, at the 

 end of three-days, his elements were found to err 30 feconds. 

 He tried alfo ellipfes of different dimenfions. 



On tlie 15th of May we were informed, by a letter from 



baron von Zach, the celebrated aftronomer of Gotha, that 



Dr. Gaufs, an ailronomer of Brunfwick, had found an el- 



lipfis which co'rrefp6nded to the firft obfervations, .On the 



3 22d 



