52 Mr. Hind on the expected Reappearance of 



given by M. Pingre in his Cometography. I then reduced the 

 elements to the year 1264, and with the assistance of a passage 

 in Thierri's poem, I fixed the time of perihelion for July 9'9 

 (old style). The passage alluded to is as follows : — 

 " Undecimumque gradum Phcebo superante Leonis, 

 Ter deno Cancri restitit ilia loco." 



With M. Pingre, I have understood by " Ter deno Cancri,'' 

 the 120th degree of longitude; but I am not quite sure that 

 this is the true interpretation. 



With perihelion and node reduced as before stated, and the 

 other elements as for 1556, an ephemeris of the comet's geo- 

 centric path in 1264 was computed. During the month of 

 July, calculation and observation agree pretty well ; but after 

 the beginning of August the theoretical places entirely differ 

 from the positions of the comet, as deduced from the accounts. 

 Instead of traversing Orion towards the end of its appearance, 

 as some historians relate, it would take a higher declination, 

 passing through Auriga and Taurus. 



Since the publication of this paper in the AstronomiscJie 

 Nachrichten, I have made some further investigations on the 

 subject, and with more success than in my first calculations. 

 A closer comparison of data showed pretty clearly that the 

 observation of March 5, on which I had chiefly relied, must 

 be erroneous as it is given by M. Pingre. In tome i. of his 

 Cometography, p. 503, we learn that on March 5 the comet 

 was almost in the right line joining the stars y and fl Virginis, 

 and was equidistant from the stars. A trigonometrical cal- 

 culation from these data gives the place of the comet in lon- 

 gitude 188'^ l', and latitude +2° 19', and this position was 

 employed in my earlier investigations. But I have recently 

 satisfied myseltj that the observation as given above cannot be 

 reconciled with those of March 3 and 4, and on subsequent 

 days, by any set of elements. The cause of this anomaly is, 

 I believe, an error in the name of the star. If instead of y 

 and fl Virginis we read 8 and i9, then the place of the comet 

 would be in longitude 188° 41', and latitude +5° 13', which 

 agrees very well with the track which the comet ought to have 

 followed, according to the other observations. 



A recalculation of the elements from an interpolated posi- 

 tion for March 5, and from those of March 9 and 14, gives 

 the following values: — 



Passage through perihelion, 1556, April 220233, G. M.T. [Old style.] 



o ' 



Longitude of perihelion 274 14"9 1 ,:, . ncK/j 



Ascending node 1^5 ^^.g j Equinox of 1556. 



Inclination 30 12-2 



Log. least distance 970323 



Motion direct. 



