As to Clustered and Double stars, they appear to give us, he says, but little promise of inhabitants. In what degree of condensation the matter of these binary systems is, compared with that of our solar system, we have no means whatever of knowing: but even granting that each individual of the pair were a sun like ours, in the nature of its material, and its state of condensation, is it probable that it resembles our Sun also in having planets revolving about it? A system of planets revolving about, or among, a pair of Suns, which are at the same time revolving about one another, is so complex a scheme [apparently], so impossible to arrange in a stable manner, that the assumption of the existence of such schemes, without a vestige of evidence, can hardly require refutation. No doubt, if we were really required to provide such a binary system of Suns with attendant planets, this would be best done by putting the planets so near to one Sun that they should not be sensibly affected by the other; and this is accordingly what has been proposed. For, as has been well said by Sir John Herschell, of the supposed planets in making this proposal, “unless closely nestled under the protecting wing of their immediate superior, the sweep of the other Sun in his perihelion passage round their own, might carry them off, or whirl them into orbits utterly inconsistent with the existence of their inhabitants.” “To assume the existence of the inhabitants, in spite of such dangers, and to provide against the dangers by placing them so close to one Sun as to be out of the reach of the other, though the whole distance of the two may not, and as we know in some cases does not, exceed the dimensions of our solar system, is showing them all the favour which is possible. But in making this provision, it is overlooked that it may not be possible to keep them in permanent orbits so near to the selected centre. Their Sun may be a vast sphere of luminous vapour, and the planets plunged into this atmosphere may, instead of describing regular orbits, plough their way in spiral paths through the nebulous abyss of its central nucleus.”[102]