179 
But the calculated place for the mean observation differed from the ob- 
servation by 40 minutes of arc. 
I then set to work to represent the observation without any hypo- 
thesis as to the nature of the conic section described. The result is— 
T= 1858, Sept. 29:95894 Greenwich M. T. 
a = 294° 27'40"-1) Mn. Eqx. 
Q=165 20 46 3} 18580 
@ =116 5859 °6 
@= 8445 23 
log. g = 9°7623494 
log. a = 271397158 
Period, 1620 years. 
The corrections of calculated by observed places are— 
In Long. In Lat. 
June8,....—-0"9.. . . +175 
AME 2D) es is, ele ON cd eis! oy 0:3 
Och Gi se we 0) SA Bote O70 
Of course, I cannot answer for the accuracy of the observations; but I 
endeavoured to select those which were best adapted to answer the end 
proposed. 
Leaving room for a wide margin in regard to the major axis of the 
orbit and its dependent period, this much seems now established, —that 
the Comet is travelling in an ellipse. The agreement in the several sets 
of elliptic elements, determined independently from separate data, is 
calculated to inspire confidence in astronomical observations and calcu- 
lations. Take, for instance, the Perihelion passage :— 
Bruhns makes the time September, 294 22h 53m Greenwich M. T. 
Lowy, ” ” 23 2 
Graham, ~- re 21 1 
” 
” 
The perihelion distance, taking the Earth’s mean distance from the 
Sun at 95,000,000 miles, is according to— 
ISTE e 4) Sirs a pasecea! MaMob reyes 54,952,520 miles, 
HG Wwayaenren ial ya cme nertetemre eas 54,957,220 ,, 
Grahams liaise Morera eae ae ee 54,963,330 ,, 
The extreme difference in the results for the time of perihelion passage 
being 9 minutes, in perihelion distance 10,810 miles, about a 5000th 
part of the whole distance—something like an error of 1 foot in mea- 
suring an English mile. 
A few deductions from the elements given above, thrown into a 
popular form, may be interesting. 
The aphelion distance is about 275 times the Earth’s mean distance 
from the Sun, about 9 times the distance of Neptune—26,000,000,000 
miles. 
The light and heat at perihelion are 8 times greater than what we 
receive from the Sun; at aphelion, 76,000 times less. 
The aphelion distance is 476 times the perihelion—so that the light 
and heat at perihelion are 226,000 times greater than at aphelion. 
