XV.
Cometary Statistics.
227
It not unfrequently happens that a comet is only discovered after its perihelion passage, when it will be receding from the the Sun, and perhaps also from the Earth. As under such circumstances its brightness will be day by day diminishing, its visibility may only extend to a few days, or a few weeks.
From an examination of a complete catalogue of calculated
Fig. 106.
ECLIPSE OF THE SUN OF MAY 17, 1882, SHOWING AN UNKNOWN COMET. (Ranyard.)
comets[1] we may obtain certain results which will here be analysed.
It appears that 492 comet apparitions have been subjected to mathematical investigation, viz.:—
| Known periodical comets | 30 |
| Subsequent returns | 108 |
| Elliptic comets not yet verified, and parabolic comets | 341 |
| Hyberbolic comets | 13 |
| 492 |
- ↑ See the Catalogue in the Appendix (post), read as a continuation of Catalogue I. in my Handbook of Astronomy, 4th ed., vol. i, p. 511.
