210 Observations on the Comet of Halley. 



in Russia, by Prof. Struve, on the 20th of August. It was seen by 

 M. Boguslawski, at Breslau, on the 21st; by M. Kunowski, at 

 Berlin, on the 22d ; by Sir James South, in England, and by M. 

 Arago, at Paris, on the 23d ; by M. Valz, at Nisraes, on the 24th ; 

 and by Prof, Schumacher, at Altona, on the 25th. The comet was 

 first seen at Yale College, on the morning of August 31st. A fruit- 

 less search had been made for it, on the preceding Monday morning, 

 (Aug. 24,) and each succeeding morning was cloudy, until the 31st. 



When the comet was first discovered, it appeared to be merely a 

 faint nebulous mass. M. Dumouchel describes it as very faint, 

 much resembling Biela's comet. Sir James South describes it, on 

 the 23d of August, as a round, well-defined nebulous body, ex- 

 tremely faint and perhaps about two minutes of space in diameter. 

 M. Arago describes it, on the 31st, as having a sensible nucleus, and 

 a nebulosity of two or three minutes in diameter, but he could dis- 

 tinguish no appearance of a train. Mr. E. J. Cooper of the county 

 of Sligo, Ireland, first saw the comet, on the 26th of August, in the 

 finder of his great telescope. His telescope is 25^ feet focal length, 

 13.3 inches aperture ; the finder is 6J feet focal length, with an ob- 

 ject glass of 4.9 inches aperture. He describes it as appearing faint 

 in the finder, but by no means so much so as other objects he had 

 seen through it. In the great telescope, it was beautifully shewn, 

 and its nucleus perfectly distinguishable. 



When first seen at this place, the comet was nearly circular, about 

 two minutes in diameter, brightest in the middle, fading away upon 

 the borders. No distinct nucleus was observed. As the large tele- 

 scope, with which the comet was discovered, has no micrometer, nor 

 an equatorial movement, no measurements could be taken, until the 

 comet became visible in smaller instruments. On the 21st of Sep- 

 tember, I noted in my journal, — the nucleus is as bright as a star of 

 the sixth magnitude — coma about six minutes in diameter, although 

 its outline is quite uncertain — think there is more coma on the lower 

 (through an astronomical eye-glass) than the upper side of the nu- 

 cleus — comet quite conspicuous in the finder. Sept. 22d, sure there 

 is more coma on the side next the sun. Sept. 25th, comet distinct- 

 ly visible to the naked eye. Oct. 3d, comet as bright to the naked 

 eye as a star of the fourth magnitude. Oct. 10th, comet quite as 

 conspicuous in the light of the moon as a Ursae Majoris. Oct. 11th, 

 train nine degrees in length, extending to 4 Draconis of Flamsteed. 



