NOTES ON COMETS.] 



ASTRONOMY. 



971 



several particulars, was discovered by Flangergues at 

 Vivieres, on the 26th of March, and observed to August 

 17th, 1812. From the laborious investigations of Arge- 

 lander. its orbit was found to be elliptical, the period 

 being 3065 years. This comet, in addition to its magni- 

 tude and the remarkable duration of its visibility, pre- 

 sented, on September 7th, a tail bent off in two branches ; 

 but these branches did not proceed from the comet itself, 

 but were hung together at a slight distance from it, and 

 separated from it by a dark interval, so that they enclosed 

 the comet as a parabola does its focus. At this period its 

 tail was 5 in length. On September 20th, Bode found 

 the length of the tail to be 10. On October llth, the 

 tail was about 13 long ; the diameter of the nebulosity 

 being 1' 20". Its maximum length appears to have oc- 

 curred in the first week of October, when the tail was 

 found to be 25 long, and about 6 broad. Sir W. Her- 

 schel paid considerable attention to the physical ap- 

 pearance of this comet, and the reader is referred to the 

 I'hilosophical Transactions, 1812, for his remarks, which 

 are too extensive to be given here. 



1811. The second comet of this year was discovered by 

 Pons on November 16th, and observed to the end of 

 January, 1812. It had a well-defined nucleus, with a 

 faint surrounding coma. 



HI 2. This comet was discovered by Pons on July 20th, 



and observed to the end of September. At first it was 



isil ile in a telescope; but in September it increased in 



I'M 'tness, and had a tail 2 in length. Professor Encke 



found Its orbit elliptical, the period being 70 '7 years. 



1813. First comet. This comet was discovered on the 

 4th of February, by the preceding observer ; and its ap- 

 pearance was that of a small confused nebula. 



1813. Second comet. This comet, the eighteenth dis- 

 covered by Pous, was first seen on March 28th. It ap- 

 pears to have been visible to the naked eye on April 

 24th and 25th, as a small round nebulosity without tail. 

 1815. This comet wag telescopic, and was discovered 

 by Olbers on March 6th. It is remarkable as being one 

 whose elliptical orbit is decided ; the periods of revolu- 

 tion, by several computers, varying from 72 years to 77 

 years. 



1818. First comet. Discovered by Pons, in Cetns, on 

 the 23rd of February. It was very faint, and has re- 

 cently been supposed to have been an appearance of the 

 comet of Bit-la. 



1818. Second comet. Discovered by Pons, on De- 

 cember 26th, 1817. It was a faint telescopic body. 



1818. Third comet. Discovered by Pons, on No- 

 vember 28th, as a small, round, and well-defined body. 

 Bessel, independently, discovered a comet on December 

 22nd, which proved to be the same body. 



1819. The first comet of this year was remarkable in 

 affording to Encke the discovery of its periodic nature, 

 and the identity of it with the comets of 1786, 1795, and 

 1805. It was discovered by Pons, on November 26th, 

 1818, as a small, ill-defined nebulosity. The history of 

 this body has been given in the preceding part of this 

 chapter. (See p. 962). 



1819. Second comet This was discovered by Pro- 

 fessor Tralles, at Berlin, on July 1st. It appeared with 

 a well-defined planetary nucleus, and a tail from 7 to 

 8 in length. 



1819. Third comet. Discovered by Pons, on July 

 12th. Encke computed its orbit, which he found to be 

 elliptical, with a period of 2052 days. 



1819. Fourth comet. Discovered by Pons, on De- 

 cember 4th ; and previously at Marseilles, by Blanpain, 

 on November 28th. Encke found its orbit elliptical, and 

 its period 4-8 years. Clausen was of opinion that it was 

 identical with the comet of 1743. 



From the year 1821 we can do little more than record 

 the various comets which have appeared in our hemi- 

 fiphuro, with their dates, and names of their discoverers : 

 1821. Discovered by Pons on January 28th. Santini 

 aw it with the naked eye on February 19th, and esti- 

 mated its tail to be 2J long. It was observed to May 

 3rd. 1822 (1). Gambart discovered this comet on May 

 12th. 1822 (2). Encko's comet. Discovered at Para- 



matta by Riimker on June 2nd. 1822 (3). Discovered 

 by Pons on May 3 1st, but not observed much in Europe 

 in consequence of its southerly declination. 1822 (4). 

 Discovered by Pons on July 13th. On August 21st it 

 was visible to the naked eye, and had a tail 1 long. 

 1823. Discovered by Pons on December 29th. Santini 

 found it on January 3rd. De Zach, on January 23rd, 

 noticed that in addition to the usual tail, directed from 

 the sun, it had another in a contrary direction, varying 

 from 4 to 7 in length. 1824 (1). Discovered by Riimker 

 on July 15th. 1824 (2). Discovered by Scheithaner, at 

 Chemitz. on July 23rd. 1825 (1). Discovered by Gam- 

 bart on May 19th, in Cassiopeia. This comet has some re- 

 semblance in its elements with the third comet of 17''0. 

 1825 (2). This small comet was discovered by Pons on 

 the 9th of August. 1825(3). Encke's comet. Discovered 

 by Valz on July 13th. 1825 (4). Discovered by Pons 

 on July 15th. It was visible to the naked eye, and in 

 October presented a remarkable appearance in the 

 heavens. 1826 (1). Gambart's or Biela's comet. Dis- 

 covered by Biela on February 27th. 1826 (2). Dis- 

 covered by Pons on November 6th, 1825. 1826 (3). 

 Discovered by Flangergues on March 29th. 1826 (4). 

 Discovered by Pons on August 7th, and observed to 

 October. 1826 (6). Discovered by Pons on October 

 22nd. It was visible to the naked eye in December, 

 with a beautiful train. 1827 (1). Discovered by Pons 

 on December 26th, 1826. 1827 (2). Discovered by 

 Pons on June 20th. 1827 (3). Discovered by Pons on 

 August 2nd. 1829. Encke s comet. Discovered by 

 Strove in 1828, October 13th. 1830 (1). Discovered 

 by Professor D'Abbadie in the Mauritius on March 

 16th. It was also seen on March 17th, during a voyage 

 from Calcutta to Boston, as a bright object, with a tail 

 8 in extent. 1830 (2). Discovered by Herapath on 

 January 7th, 1831. It exhibited a tail 2J long ; the 

 diameter of the nucleus was 3' or 4'. 



1832 (1). Encke's comet. Discovered by Mossotti, on 

 June 1, at Buenos Ayres, and at the Royal Observatory, 

 Cape of Good Hope, on the next day. It was only seen 

 once in Europe, by Professor Harding, on August 21st. 

 1832 (2). Discovered by Gambart, on July 19th. 1832 

 (3). Gambart's or Biela's comet. Discovered at Rome, 

 on August 25th. 1833. Discovered at Paramatta, by 

 Duulop, in September. 1834. Discovered by Gambart, 

 on March 8th, in Sagittarius. 1835 (1). Discovered by 

 Boguslanski, on April 20th. 1835 (2). Encke's comet. 

 Discovered by Boguslanski, on July 30th. 1835 (3). 

 Halley's comet. Discovered by Dumonchel, at Rome, 

 on August 6th. (See the history of this comet, at the 

 commencement of the chapter. )^1838. Encke's comet. 

 Discovered by Boguslanski, on August 14th. 1840 (1). 

 Discovered by Galle on December 3rd, 1839. 1840 (2). 

 Discovered by Galle on January 25th. It was very faint, 

 without any appearance of tail. 1840 (3). Discovered 

 by Galle, on March 6th. It had a tail several degrees in 

 length. 1840 (4). Discovered by Bremieker, on October 

 26th. 



1842. Encke's comet. Discovered on March 9th, by 

 Valz. 1842 (2). Discovered by Langier on October 

 28th. It was very faint, and without tail. 1843. The 

 great comet of this year is within the recollection of 

 many readers of this work. It was seen in South 

 America, on Febuary 27th, and observed afterwards in 

 Europe to the middle of April. This was the finest body 

 since the great comet of 1811. 1843 (2). Discovered 

 by Mauvais, on May 2nd. 1843 (3). Discovered by 

 Faye, on November 22nd. Its orbit is elliptical, and 

 it was again observed at the Cambridge Observatory 

 in 1850. 1844 (1). Discovered by De Vice, on August 

 22nd. 1844 (2). Discovered by Mauvais, on July 

 7th. It had a small brilliant nucleus of 3' in diameter. 

 1844 (3). Detected by Captain Wilmot, at the Cape 

 of Good Hope, on December 19th. 1845 (1). Dis- 

 covered by D' Arrest, on December 28th, 1844. 1845 

 (2). Discovered by De Vico, on February 25th. 

 1845 (3). Discovered by Coller, on June 2nd. It was 

 a beautiful object, visible to the naked eye, with a tail 

 2J in length. 1845 (4). Encke's comet. Discovered by 



