05 .] 
able to difcover it : the twilight, which was confider- 
able at the time of the comet’s riling, might hinder my 
feeing it, and I have not yet learned that it was feen 
any wereelfe. 
Mr. Pingres remarks on the two comets of this year. 
The elements of the firft comet I give as abfolutely 
certain, thofe of the fecond I cannot be fo fure of. 
The interval was only four days between the firft and 
the laft obfervation. The two laft days, and efpecially 
the laft, the twilight and the moon light rnuft have 
produced fome uncertainty in the obfervation. The 
ephemeris is founded upon the certainty of the 
elements. Suppofing there were no more than three 
or four minutes error in the two laft obfervations, this 
would not much alter the theory from what I have 
given; but an alteration in the elements would pro- 
duce two or three degrees difference in the place of 
the perihelion, which might be fufficient to render 
the reapparition of the comet uncertain in thefe high 
latitudes. Seme German obfervations fent to Mr. 
Mefiier, made in the beginning of April, induce me 
to conclude, that the place of the perihelion ought 
really to be placed a little more eaftward; but thefe 
obfervations were fent in fo confufed a manner, that 
it feems impoffible to obtain the leaft light from them. 
Perhaps we may hereafter receive from fome fouthern 
parts, obfervations fufficient to make out the true 
orbit of this comet. 
* 
Iv 
Yol. LVI. 
X. A 
