EECEEATIYE SCIENCE. 



139 



THE EXPECTED GREAT COMET. 



Of tlio many grand comets tliat have been 

 seen, and of which, any account has been 

 handed down to us, few or none have sur- 

 passed in interest the great comet of 1264, 

 the one which astronomers (and not them 

 only) are now so eagerly expecting. AU the 

 writers of the time alluded to it as the most 

 magnificent that had ever been seen by any 

 person then living ; and we are informed 

 that on the day on which it was discovered 

 Pope Urban IV. fell sick, and that he died on 

 the night on which it was last seen, October 2, 

 his illness and subsequent death being almost 

 universally ascribed to the comet's pernicious 

 influence. It seems to have been first noticed 

 about the middle of July, although it did not 

 attain its greatest brilliancy until the follow- 

 ing month, when it was seen also early in the 

 morning before sunrise. We are told that 

 from the head, which presented a very nebu- 

 lous appearance, an immense tail issued, which 

 was not less than 100° in length. , • - 



Early in March, 1556, a comet became 

 visible, which, although not so large or im- 

 posing as the one just mentioned, is stiU 

 described as " a great and brUliant star." It 

 remained visible for about one month, and 

 then disappeared. The Chinese annals, how- 

 ever, make the duration of its visibility to 

 extend to nearly two months. The comet was 

 carefully observed at Vienna by Paul Fabri- 

 cius, and a rude map of its apparent course 

 amongst the stars drawn by him has materially 

 assisted in determining its approximate ele- 

 ments. The first set were calculated by Hall ey. 

 Some fifty years afterwards, Mr. Dunthorne 

 was induced to try and determine, if possible, 

 the elements of the comet of 1264 from two 

 observations said to have been made at Cam- 

 bridge by Friar Giles, together with such in- 

 formation as was to be found in the'writings 

 of old chroniclers. His results proved so 



similar to those obtained by HaUey for the 

 comet of 1556, that he was immediately led 

 to suspect the identity of the two bodies ; 

 and as the period seemed to be about 292 

 years, he concluded that the comet would 

 again return about the year 1848. About 

 twenty years after Dunthorne had published 

 his memoir on the subject, that is to say, 

 about the year 1760, the well-known French 

 cometographer, Pingre, turned his attention 

 to the question, and after examining a large 

 number of observations and statements not 

 made use of by Dunthorne, he came to the 

 same conclusion, namely, that the comet 

 might be expected again about the year 1848. 

 The subject then remained in statu quo until 

 about twelve years ago, when Mr. J. R. Hind 

 investigated again the question of identity, 

 by collecting all the most trustworthy records 

 of the comet of 1556, and deducing an orbit 

 therefrom. The result was, that the orbit 

 obtained by him agreed so nearly with that 

 given by Fabricius in his chart, as to leave 

 no doubt that it was a very close approxima- 

 tion to the truth. 



The identity of the two bodies having 

 been satisfactorily proved, M. Bomme, of 

 Middleburg, Holland, at a vast expense of 

 time and labour, calculated the effect that 

 might be produced on the comet's period by 

 the combined attraction of the planets. 

 Taking Hind's elements as his basis, Bomme 

 found that the comet's period in 1264 was 

 302*922 years, and that planetary attraction 

 would hasten its return by 4077 days. In 

 1556 the mean period was 308*169 years, and 

 planetary attraction would accelerate its next 

 return by 3828 days ; so that the comet might 

 be again in perihelion on August 2, 1858. 

 With Halley's elements Bomme found that 

 the comet's perihelion passage would take 

 place on August 22, 1860. There is there- 



