S44 Obfervations on 



ceffary to take fuch, as had a greater interval of time 

 between them. The obfervations, of the 17th of Sep- 

 tember, the 1 7th of October, and the 1 4th of Decem- 

 ber were accordingly feleded : and the elements were 

 correded by the method of La Place, as given, in Sir 

 Henry Englefield*s treatife on the " Determination of 

 the orbits of Comets/ To fucceed with this method, 

 it was necelTary that the elements fhould be very care- 

 fully prepared. For the convenience of calculation, 

 the three obfervations were reduced to 8 o'clock, mean 

 time at Yale College, by applying to the obferved dif- 

 tances, a proportional part of the diurnal variation. 

 The right afcenfion and declination of the ftars, from 

 which the diftances of the comet had been taken, were 

 found, by comparing the catalogues of Dr. Bradley, 

 De La Caille, Piazzi, Zach, Wollafton and Pond, in 

 Vince's Aftronomy, Hutton's Dictionary, Rees* Cy- 

 clopedia, and Mendoza's Tables. Thefe generally a- 

 greed, within a very few feconds, with refpect to the 

 liars in queftion. The corrections, for precifion, aber- 

 ration, and nutation were applied ; and from the right 

 afcenfions and declinations, the latitude and longitude 

 of the liars, were calculated to feconds ; as were alfo 

 the geocentric latitudes and longitudes of the comet. 

 The latter were farther corrected, by applying the 

 equations, for the aberrations of light. The three la- 

 titudes and longitudes thus obtained, were, 



G octn. Lon. Latitude. 



September 17, 153° 64' 36" 38° 39' 56" 



October 17, 221 54 28 62 27 43 



November 14, 286 9 15 41 50 53 



Taking thefe, and the approximate perihelion dif 

 tance and time, as the balls of the fucceeding calculation; 

 I proceeded to derive from the comet's obferved longi- 

 tudes and latitudes, the arc which it defcribed, between 

 the firft and fecond obfervation j and alfo between the 

 fecond and third ; for the purpofe of comparing them, 

 with the correfponding arcs, obtained by taking the 

 difference of the three anomalies. If thefe had been 



