282 
[No. 3, 
The great Comet of 1861. 
6, 6'' — true anomalies. 
= inclination. 
Q = ascending node (longitude of). 
7r = long, of perihelion. 
D = perihelion distance. 
P == time of perihelion passage. 
The method 1 have followed is that of Olbers with slight varia- 
tions from Delambre and Bowditch. The correction, in finding the 
time of perihelion passage, depending on the true anomalies, is taken 
from Table III. of Bowditch’s appendix to the 3rd volume of La- 
place. 
I proceed to tabulate the results in a form adapted for the com- 
putation. The comet’s path is supposed to be parabolic, partly for 
facility of computation, and partly, because computations for an un- 
known elliptic orbit give varying and altogether unsatisfactory results 
even in the most skilful hands. I believe that I have determined 
the ellipse in this case : but I shrink from the labour of computing it. 
Gh.Mn 
time. 
X 
k' 
x" 
P 
P' 
P" 
L 
L' 
L" 
R R' R" 
o 
/ 
n 
• 
/ 
n 
0 
/ 
/' 
July 5 
3 
12 
133 
34 
0 
55 
16 
15 
283 
29 
15 
0.0072256 
10 
3 
12 
162 
50 
25 
61 
43 
55 
288 
16 
11 
0.0071663 
15 
3 
12 
177 
52 
42 
62 
5 
32 
293 
1 
45 
0.0070449 
5 
5 
= 10 days. 
8 ' 
tang /3' 
Let — = M : then, if we make 
8 sin (L' — A ) 
= m, 
M may be found by the formula, M = 
tang /3 — m sin (L 1 2 — A) ^ 
= - — 1 x t 
m sin (L' — A 1 ') — tang/3" 
1. To find m 
tang p' ~ 0.269166 = ( 6P 43' 55' ) 
sin!/ — A. = 9.911067= (125 25 46) 
.*. in ” 0.358099 
2. To find M 
tang P = 0.159149 Nat No. = 1.442614 
in = 0.358099 
Sin (L' — X) = 9.6307427 
9.9888417 Nat No. = .974634 
Log of N umr. = 9.6702273 
.467980 
