the celebrated Comet of 19,6^ and 1556. 



S3 



The following ephemeris of the comet for the appearance 

 in 1556, Greenwich mean midnight, old style, is deduced from 

 these elements: — 



If this ephemeris be compared with the descriptions of the 

 comet's apparent path in the heavens, we shall find the agree- 

 ment as close as could be expectetl, considering the uncer- 

 tainty and irregularity of the data. 



With the above elements reduced to 1264, the time of pe- 

 rihelion was found to be July 13*42, /. e. assuming with Pingre, 

 that the comet was in longitude 120° when the sun had reached 

 the 11th degree of Leo, according to the narration ofThierri 

 de Vaucouleurs. The geocentric places of the comet, Green- 

 wich mean midnight, old style, would then be as follows : — 



If we are to depend solely on the European accounts of 

 this comet's path, the above is liable to two objections : first, 

 too high a declination in August; and secondly, that the posi- 



