Mr. Ivory on a new Method of deducing 
I have likewise computed the remaining elements of this 
orbit by the rules laid down in No. lo, and I have found them 
to be as follows, viz. 
Inclination - - 27® i' 00" 
Place of the ascending node 77 56 32 
Place of the perihelion - 15 59 18 
The method here proposed will represent the two extreme 
observations exactly ; so that all the error of the solution will 
fall upon the middle observation. I have therefore employed 
the elements found above, to compute the geocentric place of 
the comet, Nov. 19, 8*^ 29' 44", in order to compare it with 
observation. The result of this calculation is as follows, viz. 
Calculated 
Longitude. 
Observed 
Longitude. 
Error. 
Calculated 
Latitude. 
Observed 
Latitude. 
Error. 
306 51 s'o 
0 / ii 
306 51 26 
+ 4 
39 14. 3*4 
3°9 14 48 
H 
— 14 
In Legendre's memoir I find a like comparison of the cor- 
rected elements with observation; the error in longitude being 
-J- 100"; and the error in latitude, — 55^'. It appears then 
that the errors of the elements found here are almost nothing, 
and even much less than those of the corrected elements. 
Application to the Comet of 1769. 
The places of this comet set down below are not derived 
from actual observation; they are calculated by Legendre 
from the known elements of the orbit.* In this instance there- 
fore, the inaccuracy of the results is to be attributed, not to 
* Nouvelles Methodes, p. 43, § XL. 
