CHAPTER VI.[1]
PERIODIC COMETS OF SHORT PERIODS.
Periodic Comets conveniently divided into 3 classes.—Short-period Comets in two groups.—Comets in Group I.—Encke's Comet.—The supposed Resisting Medium in space.—Its supposed effect on Encke's Comet.—Brief summary of its History.—The Resisting Medium theory not generally accepted.—Remarkable Observations in 1871.—Tempel's Second Periodical Comet (1873, ii.).—Winnecke's Comet.—Brorsen's Comet.—Tempel's First Periodical Comet (1867, ii.).—Tempel(3)-Swift's Comet.—Finlay's Comet.—D'Arrest's Comet.—Wolf's Comet.—Holmes's Comet.—Brooks's Second Periodical Comet (1889, v.).—Faye's Comet. Tuttle's Comet.—Short-period Comets in Group II.—Barnard's First Periodical Comet (1884, ii.).—Brooks's First Periodical Comet (1886, iv.).—Barnard's Second Periodical Comet (1891, iv.).—Spitaler's Comet (1890, vii.).—Perrine's Comet (1896, vii.).—Kopffs Comet.—Giacobini's Second Periodical Comet (1900, iii.).—Swift's Second Periodical Comet (1889, vi.).—Borelly's Comet (1905, ii.).—Swift's First Periodical Comet (1885, ii.).—Denning's Second Periodical Comet (1894, i.).—Metcalfs Comet (1906, vi.).—Denning's First Periodical Comet (1881, v.).—Giacobini's First Periodical Comet (1896, v.).
The comets which will be dealt with in this volume under the general designation "Periodic" may be conveniently divided into 3 main classes:—
| (I.) | Comets of Short Periods. |
| (II.) | Comets revolving in about 75 years, more or less. |
| (III.) | Comets of Long Periods. |
The comets belonging, or supposed to belong, to Class I must be put into 3 groups:—
| (i.) | Recognised members of the Solar System returning regularly at stated intervals. |
- ↑ If it should be suggested that an undue amount of space has been allotted in this work to the Short-period Comets I would answer that scarcely a year ever passes that some of them do not return to the Sun and therefore to visibility to us on the Earth: and that consequently they are available for furnishing many chances of study to the readers for whom this work is mainly intended, namely, amateurs.
