EECREATIVE SCIENCE. 



247 



A CATALOGUE OF ALL THE COMETS WHOSE ORBITS HAVE HITHEETO 



BEEN COMPUTED. 



(^Continued from page 196.) 



* According to Olbers, both these orbits will satisfy the 

 observations, and it is as yet impossible to decide between 

 them. It had a tail 15'^ long. 



* Avery fine comet, expected to return in 1860. 



* It htid a tail 22^ long. This comet formed the subject 

 of the observations of Tycho Brahe for the detection of 

 parallax. 



* Elements approximate. Observed also by Tycho Brahe. 

 s Very uncertain. It had a faint tail 3" long. 



* This orbit was computed about 15 years ago, to 

 Bee whether the comet of 1344 (ii) was identical with this 

 one. 



1 It had a tall T long. 



8 It had a tail 44^^ long. 



9 Discovered also by Tycho Brahe. 



'" An apparition of Halley' s comet. It had a tail 7^ 

 long. 



'• Somewhat uncertain. Seen at Lintz, August 27, and 

 by Kepler, September 1. 



1* A splendid comet ; it had a tail, according to Lon- 

 comontanus, 104^ long, and of a reddish hue. Said to have 

 been visible in the daytime. 



•3 Elements only approximate. 



'* By some supposed to be identical with the comet of 

 1532 ; it was not reobserved, however, as was anticipated, 

 about 1791. 



«5 It had a tail from 6^ to lO' long. 



i« It had a tail 25° long. 



1' Seen chiefly in the southern hemisphere ; both orbiti 

 satisfy the observation, and it is impossible to say which ;3 

 the correct one. 



•8 It had a tail about 1° long. 



'" It had a tail about 6*^ long. 



*" Elements only approximate. 



*i A splendid comet, whose tail nltimately reached a 

 length of trom 70° to 90°. Halley conjectured that this was 

 a return of the comet of 1106, 531—42 B.C., but this has 

 since been shown to be unlikely. The orbit here given 

 supposes a period of 8814 years ; this, however, is subject 

 to much uncertainty, inasmuch as the observation might 

 possibly be satisfied by an 805 years' ellipse, or even by an 

 hyi)erboIic orbit. 



22 An apparition of Halley' s comet. It had a tail from 

 12^ to 16= long. 



23 It had a tail varying from 2° to 4''. An elliptic orbit ; 

 period assigned, 190 years. 



^^ Its nucleus was as bright as a first magnitude star, 

 and had a tail 18^ long. 



25 Observed very roughly in the East Indies. It had a 

 tail 60° long. Pingre makes the ft = 323° 45'. 



28 Observed still more imperfectly than the last in the 

 southern hemisphere. It had a tail 18° long. 



2' Uncertain. 



2* Observed also by Thomas at Pekin. 



29 Very roughly observed ; visible to the naked eye. 



30 Discovered by Cassini, November 29, 



