It is probable that during the next three nights some light may be thrown on one of the most perplexing yet most interesting of all the problems recently suggested to the study of astronomers. It is confidently expected that many of those November meteors called Andromeds will be seen on one or other of those nights, if not on all three. No meteor systems, not even the famous systems of August and November, are more remarkable than this singular family. To explain why astronomers regard the Andromeds with so much interest, it will be necessary to speak of an object which at first sight seems in no way connected with them--an object, in fact, which, so long as it was actually known to astronomers, was never supposed to be connected with any family of meteors--the celebrated lost comet called Biela's (or, by Frenchmen, Gambart's comet). In February, 1826, Biela discovered in the constellation Aries a comet which was found to be travelling in an oval path round the sun, in a period of about six years seven and a half months. Tracing its course backwards, astronomers found that it had been seen in 1772 by Montaigne, and observed for two or three weeks in that year by Messier, the great comet hunter. Nothing very remarkable was recognised regarding this comet in 1826, except the fact that its path nearly intersects that of our own earth; so that if ever the earth is to encounter a comet, here seemed to be the comet she had to fear. Great terror was, indeed, excited by the announcement that in 1832 the comet would cross the earth's track only four or five weeks before the earth came to the place of danger. But no harm happened. In that year, and again in 1839, the comet returned quietly enough, though in 1839 it was not observed, being so placed that it was lost in the splendour of the solar rays. In February, 1846, the comet was again seen, this being the third return since its discovery in 1826, or rather, since its recognition as a member of the solar system, the eleventh since it was first seen by Montaigne. At this time everything seemed to suggest that this comet, unless our earth at some future time should absorb it, would remain for a long time a steady member of the sun's comet family. But only a few days after its detection in February, 1846, the comet was found to have divided into two, which travelled side by side until both vanished from view with increasing distance. In 1852 the companion comets reappeared, and again both continued in view till their motion carried them beyond telescopic range. As the distance between the coupled comets had increased from about 160,000 miles in 1846 to about 1,250,000 miles in 1852, astronomers anticipated a most interesting series of observations at the successive returns of the double comet to the earth's neighbourhood. Unfortunately, in 1859 the comet's course carried it athwart a part of the sky illuminated by the sun's rays, so that astronomers could not then expect to see it. But in 1866 it was