1 y8 Ivory oil a new Method of deducing 
Having completed the rest of the calculations in No. lo, the 
elements of this comet will be found as follows : viz. 
Log. of perih. dist. - 9'57^5^S5 
Time of passage, Nov. - 18-1087 
Inclination - - 15^40' 17" 
Place of ascend, node - 345 7 39 
Place of peri. - 148 11 7 
Motion direct. 
These elements Vvill not represent the two extreme observa- 
tions with perfect accuracy as in the other examples, on account 
of the correction which it was necessary to introduce, in order 
to annihilate the difference between the time in the orbit and 
the actual interval betw^een the observations : but the errors 
proceeding from this cause will be inconsiderable, and can 
hardly amount to 20.'' If we employ the same elements to 
calculate the place of the comet, Oct. 30 6867, we shall find 
these results, viz. Geo. Long. Geo. Lat. 
Calculated 183° 51' 20 
Observed 183 48 32 
error + 2 48 
15° 36' 37 
15 37 21 
error — 44 
// 
These errors are in reality less than might be expected, 
considering the disadvantages under which the computation of 
this orbit is made. Legendre has given a system of elements 
which represents the observations of the comet very exactly, 
the greatest error not exceeding 1': and, for the sake of com- 
parison, I likewise subjoin these elements, viz. 
Log. of peri. dist. - 9'574^79^ 
Time of passage, Nov. - 18*01736 
Inclination - - J 5° 58' 12'' 
