CHAPTER XV.

PAGE 261 Construction of the solar system. Matter out of which it was formed. 262 Domains of the sun out of which the matter was collected. 263 Stars nearest to the sun. Table VII. showing distances. 265 Remarks on Binary Stars. Table VIII. showing spheres of attraction between the sun and a very few. 266 Sirius actually our nearest neighbour. Form of the sun's domains of a very jagged nature. 267 Creation of matter for the nebulæ, out of which the whole universe was elaborated. Beginning of construction. 267 The law of attraction begins to operate through the agency of evolution. 268 Form of the primitive solar nebula. The jagged peaks probably soon left behind in contraction. 269 How the nebula contracted. Two views of the form it might take. Comparison of the two forms, solid or hollow. 272 The hollow centre form adopted. The jagged peaks left behind. 273 The nebula assuming a spherical form. Shreds, masses, crescents separated from one side. 274 Probable form of interior of nebula. Compared with envelopes in heads of some comets. 275 Reflections on the nebula being hollow. Opinions of others quoted. 276 The matter of a sphere solid to the centre must be inert there. 277 Further proofs of the nebula being hollow. 278 How rotary motion was instituted. 279 Such a nebula might take one of two forms. 280 The form depending on the class of nebula. Planetary in the case of the solar system. A similar conception of how rotary motion could be instituted.

In this chapter we proceed to consider how the original nebula was formed, and whether the solar system could be evolved therefrom in the manner shown in the analysis of Chapter V.

The usual way of treating the solar system has been to suppose it to have been formed out of a nebula extending far beyond the planet Neptune, generally in a vague way; although some writers have specified a limit to the distance, in order to give some definite idea of what must have been the density of the nebula at some particular period of its existence. In the first part of our work we have adopted the same plan and we mean to follow it out, because it gives us a greater degree of facility for expressing our ideas, and making them more intelligible, than by adopting a new method. But we shall previously endeavour to show where the nebula itself came from and how it was formed, which seems to us to be as necessary as to show how it was transformed into the solar system.

We understand Laplace to have supposed the nebula to have been formed out of cosmic matter in its simplest condition, and in its most primitive atomic state, collected from enormously distant regions of space by the power or law of attraction. In this we shall follow him, because we do not see the necessity for matter having to be created in the form of meteorites or meteors, or any other form, to be afterwards dissociated and reduced to the atomic state, by heat produced by collisions amongst the dissociated atoms. Surely it would show more prescience, more simplicity of work, and economy of labour, to create matter in this primitive state, than in one which required it to be passed through a mill of some kind, as it were, before it was manufactured into nebulous matter; in fact, to make brickbats in order that they should be afterwards ground down--dissociated--into impalpable powder, to render them fit to be worked up into bricks. But our first effort will be to attempt to define the collecting grounds of this cosmic matter, somewhat more particularly than has been done hitherto, as we believe that even a superficial study of them will assist us greatly in forming a more comprehensive idea of the whole solar system than anything we have met with in any of the books which we have had the opportunity of applying to for information.

The collecting grounds, then, are clearly the whole region of space to which the attractive power of the sun extends, or what astronomers would call within the sphere of his attraction. These domains, like those of any other proprietor, are limited by the domains of his neighbours. At first sight, it would seem that his neighbours are infinite in number, but a little thought will show that the number may be very limited indeed. On this small earth of ours, it is a very common thing for a landed proprietor to be able to look over the domains of his neighbours, and see those of proprietors more remote; even to look over the domains of his neighbours' neighbours, and see properties so remote that he does not even know to whom they belong nor how they are named. With much more reason, the same must be the case with the sun, more especially as he, from his own mansion-house, sees nothing of the domains, but only the mansion-houses of others, there being no landmarks, hills, fences or woods to cut off his view, as there are upon the earth; the only interruption possible to his view being that another mansion-house should come to be exactly between his and that of a farther-off neighbour. For our purposes, we will assume that his nearest neighbours are those the distances of whose mansion-houses have been measured, and will adopt the following list of them, taken from Mr. George Chambers's "Hand-Book of Astronomy,"