ABSTRACT
The hypothesis of evolution would be the only probable one, even in the absence of any clue to the particular mode of evolution. If anything is to be inferred, either from the Nebular Hypothesis, or from the analogies supplied by the planets, it must be concluded that the outermost part of the solar atmosphere consists of what are called permanent gases—gases that are not condensible into fluid even at low temperatures. The Nebular Hypothesis throws no light on the origin of diffused matter; and diffused matter as much needs accounting for as concrete matter. Thus, even were there but little direct evidence assignable for the Nebular Hypothesis, the probability of its truth would be strong. The fact that, speaking generally, the denser planets arc the nearer to the Sun, has been by some considered as adding another to the many indications of nebular origin.
