Astronomy. 177 



perfectly round and slightly luminous ; and he supposed that it was the 

 comet, which, according to the calculations of Dr Olbers, ought to pass over 

 the sun's disk on the 26th June 1819, at 5 U 47' A. M. The roundness, 

 the nebulosity, and the luminous point in its centre, appeared to M. Pas- 

 torff so remarkable, that he made an accurate drawing of it. At 8 h 26' 

 A. M., its diameter was 84".5, and its distance from the S. E. margin 6' 

 10". On the 27th June at 9 h A. M. the round spot and one of the black 

 spots had disappeared. — See Zach's Corr. Astron. vol. xi. p. 550. 



3. Singular Appearances in the Comet of 1824. — In this Journal, Vol. 

 II. p. 172, we have already noticed the curious fact observed by M. Car- 

 lini, that the light of the comet increased while its distance was increasing. 

 This remarkable fact has acquired more importance from the analogous 

 observation of M. Pons. On the 18th December 1829, M. Pons observed 

 the comet distinctly. On the 19th, he could not discover a trace of it ; 

 but on the 25th he again saw it. M. Carlini considers, that the photometri- 

 cal phenomena of that comet are explicable, by supposing that its light 

 varies inversely as the cube of its distances from the sun and the earth* 



4. Encke's Hyperbolical Elements of the Comet of 1824. — We have al- 

 ready given (Vol. II. p. 172.) Encke's first elements of the comet, but he 

 has since obtained more accurate ones from the combination of ten mean 

 places, from 27th July to 26th October 1824. These are as follows: 



Passage of Perihelion, 1824, Sept. 29th . .08813 

 Mean Time at Seeberg, 



Long, of Perihelion, Equin. Sept 29th . 4* 31' 7".3 



Long, of Ascending Node, ditto . 279* 15' 39" 



Inclination of Orbit - - 54° 36' 5S".6 



Log. of Perihelion Distance - 0.0212469 



Excentricity - . - 1.0017346 



This hyperbola, M. Encke remarks, represents the observations much 

 better than any parabola or ellipsis. 



5. Comet of 1824 discovered at Paramatta. — This comet, which has ex- 

 cited much interest in Europe, was discovered at Paramatta by Mr Rumker. 

 The observations of this able astronomer will appear in the Edinburgh 

 Transactions, vol. x. part ii. The following are the elements, com- 

 puted from these observations by a Correspondent. 



Time of Perihelion Passage ) 



Mean Time at Paramatta [ S ^ tember 29th * 25 10 " 



Long, of Perihelion . - 4* 22' 21 



Perihelion Distance - - - 1.048739 



Long, of Ascending Node - . 279" 19' 13" 



Inclination of Orbit - 54 22 22 



6. Sir Thomas Brisbane's Catalogue of the Stars in the Southern HemU 



vol. in. no. i. July 1825. at 



