by an article in the Edinburgh Review of April 1835 (vol. lxvi, p. 91).
The writer, primed with the knowledge that the period of Halley's Comet was then 75 years, and not knowing that it was not always 75 years, looked through a catalogue of previous comets and ticked off the following, separated by intervals of 75 years or multiples thereof, as apparitions of Halley's Comet, namely : 1456, 1380, 1305, 1230, 1005, 930, 550, 399, 323 A.D. and 130 B.C. We now know that every one of these identifications except the first was wrong! The attraction exercised by the planets was ignored by the writer!
The reader will remember that in anticipation of the return of Halley's Comet, both in 1759 and in 1835, great preparations were made by astronomers for the comet with the view of its being discovered at as early a date as possible, and of learning beforehand its probable path through the heavens. I do not think it can be said that anything like such extensive preparations have been made by mathematical astronomers for the return of 1910; even the date of its perihelion passage has not been predicted as confidently as one might have expected, and certainly might have wished. Seemingly, however, this will occur about the middle of April, and on that assumption, if the comet is discovered as early as December 1909, it will be an evening star up to the beginning of March, about which time it will be lost in the Sun's rays. Passing round the Sun it will reappear on the other side and will become a morning star. It will then be approaching the Earth, and will be nearest to us about May 18. As it will then be in the morning twilight it seems hopeless to expect that we shall see it as the magnificent object which it is evident that our forefathers must have seen at many of its previous apparitions, let alone the unsolved problem whether it is a rule that comets deteriorate in brilliancy after every apparition.[1]
- ↑ In Appendix IV. there will be found an Ephemeris of the comet for the months, November 1909 to July 1910, calculated partly by Crommelin and partly by D. Smart: to which I have added a statement of
