1456 was identical with the one observed by him in 1682, and Pingré converted Halley's suspicion into a certainty. The preceding return took place, as Laugier has shown, in 1378, when the comet was observed both in Europe and China; but it does not appear to have been so bright in that year as in 1456. In Sept. 1301 a great comet is mentioned by nearly all the historians of the period. It was seen as far North as Iceland. It exhibited a bright and extensive tail, which stretched across a considerable Fig. 193. HALLEY'S COMET, 684. (From the Nuremberg Chronicle.) part of the heavens. This was most likely Halley's comet. The previous apparition is not so well ascertained, but it most likely occurred in July 1223, when it is recorded in an ancient chronicle that a wonderful sign appeared in the heavens shortly before the death of Philip Augustus of France, of which event it was generally considered to be the precursor. It was only seen for 8 days. Although but little information is possessed about it, and that of a very vague character, yet it seems probable that this was Halley's comet. In April 1145 a great comet is mentioned by European historians, which is one of the most certain of our series of returns. In April 1066 an important comet became visible which astonished Europe. It is minutely, though not very clearly, described in the Chinese annals; and the path there assigned to it is found to agree with elements which bear a great resemblance to those of Halley's comet. In England it was considered the forerunner of the victory of William of Normandy, and was looked upon with universal dread. It was equal to the Full Moon in size, and its train, at first small, increased to a wonderful length. Almost every historian and writer of the 11th century bears witness to the splendour of the comet of 1066, and there can be but little doubt that it was Halley's. Previous to this year the comet appeared in 989, 912, 837, 760, 684, 608, 530, 451, 373, 295, 218, 141, 66 A.D., and 11 B.C., all of which apparitions have been identified by Hind". Concerning the comets belonging to Class III. (comets of long period), it is not necessary to notice them further here; they will be found in the Catalogue, passim. Flammarion, making use of some previous labours in this field by Kirkwood and others, has worked out the idea of particular comets being associated with particular planets in a way which has yielded some results too curious and interesting to be passed over. In addition to the 1st or Jupiter group to which reference has already been made, he finds that every major planet beyond Jupiter seems to have a group of comets attached to it; and moreover, as there is a group of comets without a known planetary leader, he makes bold to speculate that this fact is a proof that a Trans-Neptunian planet exists and will one day be found. The following are Flammarion's groups, the figures appended representing in Radii of the Earth's orbit the mean distances of the respective planets and the aphelion distances of the respective comets : Flammarion finally hints at the speculation that the undiscovered planet must, if it be related to the comets of the 5th group, revolve at somewhere about twice the distance of Neptune, say, in a period of 300 years. Y L'Astronomie, vol. iii. p. 89, March 1884. I have corrected several im portant mistakes or misprints in the French original. CHAPTER III. REMARKABLE COMETS. The Great Comet of 1811.-The Great Comet of 1843.-The Great Comet of 1858. -The Comet of 1860 (iii.).—The Great Comet of 1861.-The Comet of 1862 (iii.).—The Comet of 1864 (ii.).—The Comet of 1874 (iii.).—The Comet of 1882 (iii.). THE HE comets which might be included under the above head are so numerous as to make it impossible that all should receive full attention. I must therefore limit myself to some few of the most interesting, premising that Grant includes the following comets under the designation "remarkable" : : The Comet of 1811 (i.) is one of the most celebrated of modern times. It was discovered by Flaugergues, at Viviers, on March 26, 1811, and was last seen by Wisniewski at Neu-Tscherkask, on Aug. 17, 1812. In the autumnal months of 1811 it shone very conspicuously, and its considerable Northern declination caused it to remain visible throughout the night for many weeks. The extreme length of the tail at the beginning of October was about 25°, and its breadth about 6°. Sir W. Herschel paid particular attention to this comet, and the observations which he made are |