84 On the Comet of October 1st, 1847. 
On the evening of the 2d, its change of place was manifest, 
and at 11h, 46m. 55s., its meridian passage was taken by a transit 
instrument, the right ascension being Oh. 11m. 08-96s., and decli- 
nation +84° 22/, as indicated by the instrument. No appearance 
of condensation of light towards its center, nor any indication of a 
train could be detected. It is evident that its apparition even to 
the telescope was sudden. Its first apparent motion was incon- 
siderable, and the region of its discovery had been see tbe 
swept over by the assistant observer at Cambridge, with his ex- 
cellent comet-seeker, and as late as the previous evening. "This 
idea is also strengthened by the subsequent rapid increase of the 
brilliancy of the comet, and the acceleration of its apparent mo- 
tion. In clearer skies and better instruments an earlier obser- 
vation might have been m 
On the ‘3d, its motion me bsiatindiens, had much increased, and 
at 9h. 27m. its right ascension was found to be 22h. 10m. ‘49s., 
and its declination +84° 52’. A slight increase of light towards 
its centre was noticed by one observer. The observations of this 
evening were much interrupted by passing clouds, and during a 
period of obscurity, the comet must have passed very near the star 
7851 of the Catalogue of the British Association. The obser- 
vations of the evening were very imperfect. On the 4th, all ob- 
servations were forbidden by the weather. On the 5th, the eve- 
ning was delightful. At an early period, it was evident that the 
comet would transit a fixed star of the fifth magnitude, number 
6206 according to the catalogue above named, or 40, according to 
Flamsteed, and this means was relied upon for the determination 
of its position, and it did not disappoint the observer. Prepara- 
tions were made to note the beginning and end of the transit; 
but the border of the comet proved too uncertain to rely upon. 
At 10h. 54m., however, the star appeared to be exactly in the 
centre of the comet ; during several seconds, it was impossib 
to determine, with a power of 100, in which direction, was the 
greatest extent of nebulosity. It appeared in fact like the nu- 
cleus of the comet shining through it with undiminished bril- 
liancy. The position of this star as given in the catalogue for 
the first day of first month, January, 1850, is, R. A. 18. 11m. 
15-40s., and Declination 4792 5 53/ 266, which, being reduced, 
gives for the star and hence for the centre.of the comet at the 
period of observation, R. A. 18h. 11m. 13-40s., and Declination 
WET9° 57’ 576, and this may be deemed the ‘best ene ape ob- 
tained at Nantucket. 
On Hbon on Part the comet was manifest to the naked eye, and con- 
nerease in brightness till the light of the moon obseur- 
‘senciege a Cambridge, it exhibited a: Enis teeky 
ing 7 toward the Equinoctial and slightly. dimin- 
ai ng a pposite to the sun. ‘The fol- 
aw, ihe 
i. 
hd 
44 
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