arrival of this grand comet at the time originally fixed upon by Dunthorne, Pingré, and others. It is an important circumstance, as bearing on the question of identity of the comets of 1264 and 1556, that about 289 years anterior to the former epoch, or A.D. 975, a comet of great apparent magnitude was visible, which may very possibly have been the same. It was observed in Europe from August to October, during the reign of John Zimisces. The Chinese saw it about the middle of July, and traced its course through Hydra, Leo, Cancer, Gemini, and Taurus, into Aries, where it was lost after a visibility of three days. It exhibited a tail 40° in length, and was evidently a comet of unusual brilliancy. Supposing the elements fixed by the author for 1556, it is found that the observed track may be very closely represented, the perihelion passage being assumed to take place early in August, 975. A comet observed in China in the summer of 683, and one seen in the circumpolar heavens, A.D. 104, present some indications of identity with the grand comet of 1264 and 1556, but the accounts we possess are too vague to admit of anything more than conjecture. |