1861.] 
The great Comet of 1861. 
289 
8. To find D — perihelion distance. 
6 
D = cos 2 — xr = cos 2 
2 
6 " 
X r> 
cos 1 0 = 9.9733386 
2 
C03 £ I 
0 
COS 2 — = 9.9166772 
2 
r = 9.9699588 
' = 9.9518601 
2 
9.9037208 
r" = 0.0129150 
D = 9.9166360 
.-. D = 
D = 9.9166358 
9. 
.825346 
Lastly to find the time of passing the perihelion. 
P = D| 6 (Tab. III. Bowditch). P" = Df x 6" (Tab. III. B.) 
D = 9.916636 
3 
2) 9.749908 
D# = 9.874954 
0 Tab. III. 1.491470 
D4 = 9.874954 
1.646842 
1.366424 
23 d. 250 
J uly 5 d. 133 
1.521796 
33d. 250 
July 15 d. 133 
June lid. 883 
June lid. 883 
Greenwich Mn. tune of perihelion passage, June 11 A. 217*. 11ot. 31s. 
The elements of the comet by this set of observations are 
Prom other sets. 
Asc. Node 279° V 4" 278° 59' 32" 
Inclination, 85° 31' 3" 
Perihel. Long., 249° 40' 9" 
Dist 825346. 
Passage, June lid. 217*. 2. June lid. 237*. — Juno 12d. 37*. 
Motion, Direct. 
The celebrated astronomer, Monsr. Plantamour of Geneva, gives 
the following elements, which I found in the London Review of July 
27th. 
Asc. Node, 278° 59' 
Inclination, Omitted. Hind and Pape giveJ85° 37' 
P. Long., 249° 41' and 85° 38'. 
— Dist., 82424. 
— Pass., June lid, 217*. 36)». Hind gives June, 12d. 47*. 
Motion, Direct. 
