ON THE NEW PLANET CERES. 51 



Again, fuppofing the point of mean diftance to be at 96°, 

 wc have in that cafe, 



As the aphelion diftance, 28498 4,45481 



Is to the perihelion dift. 26848 4,42891 



So is the tangent of 48° 10,0 1556 



MMaMMafert 



14,47447 

 4,45481 



To the tangent of 46° 17' nearly 10,01966 



Then 96°— 82° 34'=3 G 26' is the greateft equation, as be- 

 fore. 



Hence it is indubitably proved, that the equation, as given The equation 

 by Gaufs, is much too great for the eccentricity ; and it ap- f^" * t ^ 

 pears alfo, according to what has been already afierted, that ihe eccentricity j 

 the equation at 92° and 96° of mean anomaly is nearly the 

 fame ; that is to fay, the difference will only be in the fecund?. 

 But the greateft equation of a planet is ufually determined °f th . e eccentri- 

 from a feries of obfervations antecedently to the calculation of 

 the eccentricity : therefore the error which has been detected 

 may be in the eccentricity, and not in the equation ; in which 

 cafe, by reverting the analogy already ufed, we (hall have 

 this calculation, viz. As unity : mean diftance 27673 :: natu- 

 ral line of 4° 43' 50^" or 08247,4 : 2282,2 for the requifite 

 eccentricity. But it will be moft eafy to determine in which J" 1 * tn '« W 'U be 

 of the two elements the error has been committed, when the the per^^when 

 whole period has been accurately afcertained. determined. 



When it was mentioned in the former paper on this fubject, Ofervations of 

 that oppofitions and conjunctions were of importance to be op^firions^a d 

 obferved, the reafon was omitted to be explained ; which is, their ufe. 

 that when a fuperior planet is in oppofition, or an inferior one 

 in conjunction, the obferved geocentric longitudes are alfo 

 heliocentric longitudes, without calculation or reference to 

 diftance and eccentricity ; becaufe in fuch relative filiations 

 there is no parallax of the orb : and it is well known to aftro- 

 nomers, that when an oppofition happens at the place of mean 

 diftance of a fuperior planet, half the difference between the 

 heliocentric place, by calculation of mean motion, and of the 

 place as obferved at that time, is equal to the greateft equation. 

 The 1 3th of March ult. was the day on which the aftronomers 

 on the continent predicted that an oppofition of Ceres would 



E 2 occur j 



