ON TWO CELESTIAL BODIES. 147 



greater! inducements to believe, it would be a favourable cir- 

 cumftance to lead us to a more perfect knowledge of the na- 

 ture of comets and their orbits ; for inftance, the comet of the 

 year 1770, which Mr. Lexell has fheWn to have moved in ah 

 elliptical orbit> fuch as would make the time of its periodical 

 return only about b\ years: if this fhould ftill remain in our 

 fyftem, which is however doubtful, we ought to look for it 

 under the form of an afteroid. 



If thefe confiderations mould be admitted, it might be obi 

 jedted, that afteroids Were only comets in difguife ; but, if we 

 were to allow that comets, afteroids, and even planets, might 

 poffibly be the fame fort of celeftial bodies under different cir- 

 cumftances, the neceflary diftincVion arifing from fuch diffe- 

 rence, would fully authorife us to call them by different names. 



It is to be hoped that time will foon throw a greater light 

 upon this fubject; for which reafon, it would be premature to 

 add any other remarks, though many extend ve views relating 

 to the folar fyftem might certainly be hinted at. 



Additional Obfervations relating to the Appearances of the Additional ob* 

 Afteroids Ceres and Pallas. fervations. 



May 4, 12 h 40\ 10-feet refleclor; power 51 6f. I com- The comas do 

 pared Ceres with tw6 fixed ftars, which; in the finder, ap- notmuch exceed 



i i r i , r • i • i i o tnofe of the 



peared to be or very nearly the lame magnitude with the afte- fi xe< j ft ars , 



roid, and found that its coma exceeds their aberration but in a 

 very fmall degree. 



12 h 50'. 20- feet reflector ; power 477. I viewed Ceres, 

 in order to compare its appearance with regard to hazinefs, 

 aberration, atmofphere, or coma, whatever we may call it, to 

 the fame phenomena of the fixed ftars ; and found that the 

 coma of the afteroid did not much exceed that of the ftars. 



I alfo found, that even the fixed ftars differ confiderably in 

 this refpeft among themfelves. The fmaller they are, the larger 

 in proportion will the attendant hazinefs fhew itfelf. A ftar 

 that is fcarcely perceptible, becomes a fmall nebulofity. 



1 0-feet reflector. 13 h 10'. I compared the appearance of 

 Pallas with two equal fixed ftars ; and found that the coma of 

 this afteroid but very little exceeds the aberration of the ftars. 



14 h 5', 20-feet reflector. I viewed Pallas; and, with a 

 magnifying power of 477, its difk was viable. The coma of 

 this afteroid is a little ftronger than that which fixed ilafs of 

 the fame fize generally have. 



L2 Qn 



