Let us note the exact amount of evidence constituted by the speculations of the foregoing letter, on behalf of the Hypothesis that all existing stellar bodies sprung by virtue of the law of attraction, from the bosom of a chaos similar to the vague masses I have described. In so far as this Hypothesis undertakes to explain the nebulæ, I do not conceive that much of accessible knowledge is now wanting to confirm it; for, the agreement of the forms of the nebular substance with the natural results of the persevering action of gravity, seems almost demonstrated. But it must not be forgotten that there is another correlative and very extensive inquiry which this truth has not touched; The Hypothesis must alsoexplain the stars. If it is the true Cosmogony, and we have at length approached a right theory of the Formation of Things, we should indeed obtain from it a satisfactory idea of the meaning of that curious progression of structure, which so strikingly characterises the Nebulous masses; but it is no less imperative that it exhibit with proper distinctness, how the mass of stars around us, along with their peculiar features and arrangements, might have been evolved, in obedience to known mechanical laws, by the condensation of Nebulæ.