9. Perhaps these revolving specks of nebulæ are the outriders of the zodiacal light; portions of it, which, being external to the permanently nebulous central mass, have broken into patches, and are seen as stars for the moment that we are near to them. And if this be true, we have to correct, in a certain way, what we have previously said of the zodiacal light;--that no one had thought of resolving it into stars: for it would thus appear, that in its outer region, it resolves itself into stars, visible, though but for a moment, to the naked eye. 10. And thus, all these phenomena concur in making it appear probable, that the Earth is placed in that region of the solar system in which the planet-forming powers are most vigorous and potent;--between the region of permanent nebulous vapor, and the region of mere shreds and specks of planetary matter, such as are the satellites and the planetoidal group. And from these views, finally it follows, that the Earth is really the largest planetary body in the Solar System. The vast globes of Jupiter and Saturn, Uranus and Neptune, which roll far above her, are still only huge masses of cloud and vapor, water and air; which, from their enormous size, are ponderous enough to retain round them a body of small satellites, perhaps, in some degree at least, solid; and which have perhaps a small lump, or a few similar lumps, of planetary matter at the centre of their watery globe. The Earth is really the domestic hearth of this Solar System; adjusted between the hot and fiery haze on one side, the cold and watery vapor on the other. This region only is fit to be a domestic hearth, a seat of habitation; and in this region is placed the largest solid globe of our system; and on this globe, by a series of creative operations, entirely different from any of those which separated the solid from the vaporous, the cold from the hot, the moist from the dry, have been established, in succession, plants, and animals, and man. So that the habitation has been occupied; the domestic hearth has been surrounded by its family; the fitnesses so wonderfully combined have been employed; and the Earth alone, of all the parts of the frame which revolves round the Sun, has become a World.