With a period of 27 years, the perihelion being interior to the earth's orbit, the aphelion distance of the meteors would be very nearly equal to the distance of Uranus. The next shower, if the assumed period be correct, ought to occur about 1884. It is worthy of remark that near the time of the last (hypothetical) return Mr. Du Chaillu witnessed the meteors of this epoch, in considerable numbers, in the interior of Africa.
The Meteors of December 12.
Meteoric showers have occurred about the 12th of December in the following years:
1. A.D. 901. "The whole hemisphere was filled with those meteors called falling-stars from midnight till morning, to the great surprise of the beholders in Egypt."
2. In 930 a remarkable shower of falling stars was observed in China.
3. Extraordinary meteoric phenomena were observed at Zurich at the same epoch in 1571.
4. On the night of the 11th and 12th of December, 1833, a great number of shooting-stars were seen at Parma. At the maximum as many as ten were visible at the same time.
5. (Doubtful.) 1861, 1862, and 1863. Maximum probably in 1862. The meteors at this return were far from being comparable in numbers with the ancient displays. The shower, however, was distinctly observed. R. P. Greg, Esq., of Manchester, England, says the period of December 12, 1862, was "exceedingly well defined."
These dates indicate a period of about 291⁄8 years. Thus:
| 901 to 930 | 1 period of 29.000 years. |
| 930 to 1571 | 22 periods of 29.136 " |
| 1571 to 1833 | 9 periods of 29.111 " |
| 1833 to 1862 | 1 period of 29.000 " |