On the Great Comet of 1843. 201 
vations by the method of least squares. ‘The elliptic elements 
should of course be used in computing perturbations. 
We have the honor to be your obedient servants, 
Sears C. Waker, 
E. Oris Kenpatu. 
"To Messrs. John K. Kane, Alexander Dallas Bache, LL. D., 
Robley Dunglison, M. D., Joshua Francis Fisher. 
High School Observatory, Philadelphia, June 16th, 1843. 
To THE SECRETARIES OF THE AMERICAN PHILOSOPHICAL SOCIETY. 
Gentlemen—Since writing the letter which was read at the 
centennial meeting of the Society, we have compared our normal 
places of the comet on the 20th and 30th of March with the Euro- 
pean observations. We have not been able to find any later than 
the 31st of March, and must still rely on our own measures for the 
comet’s place on the 9th of April. In order to test the normal 
places for March 20th and 30th, we subjoin the differences there- 
from of the European observations referred to the date of Green- 
wich mean midnight, after rejecting two in all, whose discrepan- 
cies from the mean result exceeded fifty seconds of space. 
Observation compared Correction of | Correction of Date of normal 
i normal place, Ag. | normal place, Ad. place. 
atis, March 19.5 | + ‘7/2 + 2.2 March 20.5 
Geneva, “ 19.5) + 7.0 + 2.1 
Rome, “« 19.5 | +81 .0 + 5.0 
Rome, ee peas eae a3 +35 .1 
Berlin, “« 205) + 5.4 —23 .9 
Munich, “« 20.5 |} + 3.4 —21 .4 
Manheim, “ 21.5 | —13 .9 —26 .1 
Geneva, “« 21.5 | — 2.6 —28 .3 
Bonn, “« 215) +.0.5 —28 .1 
Berlin, CO LO | eum dk —20 .9 
Munich, 621.5 | —23 .5 + 0.5 
Vienna, cio) Ia) +31 .0 
Mean correction, | —00".0 [ees GE 
Manheim, March 29.5 | + 0.9 13/9 March 30.5 
Bonn, $6 29.5) i 3) 8 —16 .1 
Manheim, “ 30.5 | +20 6 +15 .5 
Berlin, “« 630.5) + 2.1 —19 5 
Berlin, “31.5 | +33 3 — 0.8 
Mean correction, +10".7 — 7.0 
If we allow to the High School observations the same weight 
as that of one European observatory, then the normal places of 
Vol. xtv, No. 1.—April—June, 1843. 26 
