The Meteors of Biela's Comet

Abstract

MR. WILLIS'S inference that some Bielan meteors may be visible this year seems quite in accordance with the historical facts of the stream. The parent comet was observed between 1772 and 1852, and its mean period from twelve revolutions was 6.71 years. If this also represents its mean orbital time since 1852, perihelion would occur in September 1899. But the last four observed returns from 1826 to 1852 averaged 6.62 years, which would indicate perihelion at the end of January 1899. On the whole it seems highly probable that when the earth crossed the comet's orbit in November 1898 it was too far in advance of the cometary nucleus for any meteoric shower to result. It also appears likely that at the meeting, now imminent, of the earth and cometary orbit, the former will encounter a section of the stream too far in the wake of the comet for it to be very thickly strewn with its material. However, this remains to be seen. The apparition of a fine shower of these meteors on November 23, 1892, sufficiently proves that the period of thirteen years intervening between the rich displays of 1872 and 1885 did not exactly represent two returns of the same part of the meteoric group. In 1872 the earth passed through a section of the stream following the comet, while in 1885 it encountered a part preceding the comet. Intervals of twenty years (equivalent to about three periodical revolutions of the comet) seem favourable to recurrences of the meteoric shower as it was observed in 1798 and 1838 (including two periods of twenty years) and in 1872 and 1892. I think the next brilliant return of the meteors will certainly occur in 1905, and that a minor display is very likely to be visible in 1899. If so, the meteors will appear in the early evening of November 24 next, the longitude of the node being 242°.2.