On the Great Comet of 1843. 197 
an increasing perihelion distance till this point is again brought 
within the nucleus in the depths of space. Very truly yours, 
Wo. H. C. Bartverr. 
A. D. Bacue, LL. D., Philad. 
We subjoin Encke’s hyperbolic elements, and also our own. 
The latter have been recomputed, after correcting a slight over- 
sight in our calculations, kindly pointed out by Prof. Anderson. 
Encke’s ephemeris agrees beautifully with his observations. Our 
hyperbolic elements give an ephemeris corresponding with our 
normal places within one second of space : 
Encke. W., K. and D. 
Perihelion passage, § —- Feb. 274.49778 27458939 
m. t. Berlin. i m. t. Green 
Longitude of perihelion, 2ZT9° 2! 29.9 Fe 280° 44 3.7 
’ m. “ March 0 m. eq. March 30 
Long. asc. node, ; : 15 24.9 15 57 3.2 
Inclination, . . 2 = 12 38.2 34 19 52.0 
Eccentricity, . «=~. ~—Ss«:1.00021825 1.00090495 
Gaussian angle,*¥ . . +©19 11’ 49”.0 2° 26’ 12”.1 
Perihelion distance, . .  0.00521966 0.00410367 
Daily motion retrograde, 13/.175559 159’.58936 
It will appear on comparing these Sete, that they agree 
very well, éxcepting the eccentricity and its secant, the Gaussian 
angle. This i is always the most uncertain element in such inves- 
tigations. We might a priori believe that our result has more 
weight, from being derived from twenty two days’ motion of the 
comet, whereas Encke’s was derived from only eight days’ mo- 
tion. Moreover, our places were normal, or average places, and 
his derived from observations of a single night. A third argu- 
ment in favor of our elements is, that they were derived directly 
from the normal places, without any hypothesis respecting the 
conic section. Whereas Encke’s were obtained by variations 
from a parabolic curve acknowledged to be erroneous. ‘That 
there can be no error in the process of computation by Mr. Downes 
and ourselves, is shown by the fact that the elements reproduce 
by computation our normal places, after applying the following 
small corrections, viz. 
* This angle is the arc whose secant is the same as the eccentricity. 
