Page:The story of the comets.djvu/109

VI. northern declination. Another point which has been noted is that several weeks after perihelion the comet rapidly diminishes in brightness whilst its diameter increases considerably, even to 8' or 10' of arc.

According to D'Arrest the present orbit was due to the action of Jupiter in 1842, and according to W. E. Plummer serious disturbances from the same cause will happen in 1937, if the comet should last as long.

On April 3, 1867, Tempel at Milan discovered a small comet. It had a nucleus eccentrically placed in an oval coma, and Talmage, on May 3, thought that the nucleus appeared to have a division across its centre. The comet remained visible for about 4 months, which enabled its orbit to be ascertained to be without doubt an ellipse of short period, which Searle fixed at 2064 days and Bruhns at 2074 days. It returned to perihelion in 1873 and was found by Stephan at Marseilles on April 3. It was due to return to perihelion in May 1879, in Sept. 1885, in March 1892, in Oct. 1898, and in April 1905, and not having been seen in any of those years, perhaps it ought to be regarded as lost. Gautier found that the period of the comet, which was at first supposed to be about 6 years, had by 1885 been increased by no less than 5 months owing to the influence of Jupiter on its orbit.

On Sept. 26, 1886, Finlay, at the Royal Observatory, Cape of Good Hope, discovered a small tailless comet, 1' in diameter. It was at first thought that it might possibly be identical with the lost Comet of Di Vico, but subsequent investigation disproved this idea; this comet is, however, now to be regarded as a recognised member of our system. It was re-discovered on May 17, 1893, shining like a star of the 11th mag. and still without a tail. It was missed in the winter of 1899-1900