Some pleasant dreams of past decades have vanished in the light of recent knowledge. The nebular hypothesis, that wondrous conception of Swedenborg, elaborated by La Place and espoused by William Herschel and so many others, as affording a full explanation of the method by which our worlds were shaped into their present forms, has ceased to have general acceptance. M. Maedler, director of the Dorpat Observatory in 1846, had a firm persuasion that the collective body of stars visible to us has a movement of revolution about a centre situated in the group of the Pleiades, and corresponding to the star Alcyone. But this notion of a central sun around which all the solar system is circling has lost ground. The distortion in the orbit of the planet Mercury has been accounted for by the urgent suggestion that there must be some planet, as yet undiscovered, that disturbs the regularity of Mercury’s movements, but whose orbit is so near to the sun as to baffle all ordinary efforts to see it. It has received, by anticipation, the prenatal name of Vulcan. Many eyes have peered most intently into the region indicated, and some few have imagined they had found what they sought. A physician of the village of Orgeres, France, M. Lescarbault by name, on March 20, 1859, saw such an object pass over the sun’s disk. The skillful Le Verrier was much impressed by this physician’s minute account of the occurrence. But there was no confirmation of the alleged discovery. At the time of subsequent eclipses that part of the heavens has been repeatedly examined closely, but in vain. So we must wait longer before believing that Vulcan does exist. When, in 1877, Professor Hall, through the powerful telescope at Washington, saw that Mars was attended by two tiny satellites, he put a permanent injunction on the further use of the once favorite phrase, “The snowy poles of moonless Mars.” And so of the question oft discussed in the old-time debating societies, “Are the planets inhabited?” It may still be left in the hands of young collegians, notwithstanding the fact that our largest telescopes give only negative testimony. In a solar eclipse in February, 1736, that was annular in shape, just before the sun was completely hidden, the narrow horn of light seemed to break into a series of dots, or luminous points, which, when noted again a century later and described by Francis Baily, received the name of “Baily Beads.” It was attempted to explain this as caused by the moon’s mountains cutting off the last rays of sunlight, or else as produced by irradiation. But with the advent of stronger telescopic power the phenomenon has come to an end.