{| align="center" cellpadding="5" cellspacing="0"
|- | | Comet's Date. | | Period in Years. |- | |
The Comet of 1864 (ii.) |
| | 2,800,000 |- | |
The Comet of 1863 (i.) |
| | 1,840,000 |- | |
The Comet of 1882 (i.) |
| | 400,000 |- | |
The Comet of 1845 (ii.) |
| | 115,000 |- | |
The Comet of 1844 (ii.) |
| | 102,050 |- | |
The Comet of 1898 (x.) |
| | 87,000 |- | |
The Comet of 1780 (i.) |
| | 75,314 |- | |
The Comet of 1847 (iv.) |
| | 43,954 |- | |
The Comet of 1877 (iii.) |
| | 28,000 |- | |
The Comet of 1680 |
| | 15,864 |- | |
The Comet of 1874 (iii.) |
| | 13,918 |- | |
The Comet of 1840 (ii.) |
| | 13,864 |- |}
It would be a waste of space to extend this Table, but of course there are many comets on record with periods less than 10,000 years and more than 80 years.
Amongst the long-period comets enrolled as such by astronomers the Comet of 1264 seems to deserve some special mention, and for a threefold reason: its magnificent brilliancy; the great amount of time which has been dedicated to the study of its orbit during a century and a half, beginning with Halley and ending with Hind; and the extreme disappointment experienced both by astronomers and the public at its non-appearance in 1858 or in the years immediately following, for it was assumed that another very grand comet which appeared in 3556 was identical with it.
Making every allowance for the extravagance of the language often employed in bygone centuries to describe comets, it seems extremely probable that both these comets must have been comets of remarkable brilliancy. The observations of both have been handed down with unusual perspicuity both by Chinese and European writers; and the numerous and experienced computers who have worked at their orbits had no difficulty in arriving at the conclusion that the comets were identical, and that the period was something between 302 and 308 years. Reckoning backwards, Hind also found