_Nomenclature of Comets._—It must be confessed that no perfectly satisfactory method has yet been devised as regards the naming of comets. The plan of affixing Roman numbers progressively for each year, according to date of perihelion passage, answers pretty well, though a little confusion is sometimes caused by prematurely affixing the number, especially when two comets are discovered successively, the first of which is a long time before perihelion, and the second considerably after it. Until a comet can be safely assigned its catalogue place, it is preferable to refer to it by the name of the discoverer and date of discovery. This is more distinctive than the common method of lettering comets according to the epochs of their detection. As to periodical comets, it is not difficult to find some inconsistencies in their names. In the case of Halley’s Comet (1682, discovered by Flamsteed) and Encke’s Comet (1819 I., discovered by Pons), it was most fitting that they should be known to posterity by the names of the two able computers whose investigations first revealed to us comets of long and short period respectively. Under ordinary circumstances the name of the discoverer is applied to a comet as a means of convenient reference, and perhaps as a suitable recognition of the patient labours of the man who first announced it to the world. The plan seems to have been to name comets after those fortunate persons who sighted them at the particular apparition during which periodicity was determined. Thus Tuttle’s Comet (1858 I.) had been seen as long before as 1790 by Mechain, and Biela’s (1826 I.) was previously observed in 1772 by Montaigne, and in 1805 by Pons. It is, however, strange that a comet found by Pons in 1819 (III. of that year), and which Encke showed to be revolving in an ellipse with a periodic time of 5½ years, should be called after Winnecke, who rediscovered it in 1858. To Pons the real priority belongs, though Winnecke deserves much praise for redetecting and identifying this body after it had effected six unobserved returns to perihelion. It is also curious to find that the comet of short period discovered by Swift in 1880 is called “Tempel’s 3rd Comet” in Galle’s catalogue (1885), from the fact that Tempel found it at a previous return (1869), when, however, its period was not ascertained. There is little doubt that the title justly belongs to Swift. Tempel himself called it “Swift’s Comet.” One plan should in fairness to observers be consistently adhered to. If comets are to be called after their original discoverers, then Biela’s Comet should be known as “Montaigne’s,” Tuttle’s as “Mechain’s,” &c. _Curiosities of Comets._—The comet of 1729, which was hardly visible to the naked eye, has far the greatest perihelion distance (4·0435) of any comet known. Barnard’s Comet (1885 II.) comes next with a perihelion distance of 2·5068.