154 HISTORY OF ASTRONOMY. 



pearance. It was seen in some places near the end of 

 February, and was equal in size to half the moon. Its 

 beard was short, and was unsteady. It exhibited a move- 

 ment like that of a flame, or a torch disturbed by the 

 wind. The length- of its tail was about four degrees ; its 

 color resembled that of Mars, but somewhat paler. On 

 the 12th of March it had reached a north declination of 

 42, and it moved over 15 of a great circle in a day. It 

 was then distant from the earth only about seven millions 

 of miles, and showed considerable train. It continued 

 visible until the 23d of April, when it disappeared in 

 consequence of its proximity to the sun. Dr. Halley, 

 the second astronomer royal of England, computed the 

 elements of this comet; but owing to the imperfect nature 

 of the observations, his elements were not considered 

 very exact. Mr. Dunthorne's results for the comet of 

 1264 were so similar to those which Halley had given 

 for the comet of 1556, that he was immediately led to 

 conclude these two bodies to be identical, and the period 

 being probably about 292 years, he surmised that a re- 

 appearance might be expected about 1848. 



About twenty years later, M, Pingre collected together 

 all the accounts he could find relative to the comet of 

 1264, and the result of an elaborate investigation was 

 that the paths of the comets of 1264 and 1556 might be 

 represented with tolerable accuracy by elements very 

 closely similar; and hence he regarded those bodies as 

 identical, and coincided with Mr. Dunthorne in anticipa- 

 ting its re-appearance about the year 1848. 



