given against their opinion, among others the variations in rate of rotation we so frequently see used in favour of other notions; but we shall content ourselves with the best one of all, which is this: The pressures in the interior of the earth must be so enormous that they are quite sufficient to compress steel, or adamant if that is supposed to be more resistant, into any shape whatever, almost as if it were dough, and there can be no doubt--mathematics notwithstanding--that the earth has the form, to-day, due to its present rate of rotation. We shall have to return to this subject some time hence, if we live to complete what we have taken in hand. How many things there are, in what is considered to be astronomical science, that have not been properly thought out to the end, and to what strange notions they have given rise! This one of the rotation of the moon which we have been discussing, has evidently given occasion for the conception of the theory that the absence of atmosphere and seas from the moon is the natural consequence of the kinetic theory of gases; and the author of the theory, and its supporters, have never, apparently, taken the trouble to think whether their absence from the near hemisphere is a satisfactory and convincing proof of there not being any air or water on the far-off one. In what we have proposed to write many similar examples of want of study will be met with, but we do not intend to call special attention to them, unless it be in cases where we consider it to be of some importance to do so. In fact we have already been working on that plan. CHAPTER III. PAGE 49 Remarks on some of the principal cosmogonies. Ancient notions. 50 The Nebular hypothesis of Laplace. Early opinions on it. Received into favour. Again condemned as erroneous. 51 Defects attributed to it as fatal. New cosmogonies advanced. 53 Dr. Croll's collision, or impact, theory discussed. 59 Dr. Braun's cosmogony examined. 61 M. Faye's "Origine du Monde" defined. 65 Shown to be without proper foundation, confused, and in some parts contradictory. 70 Reference to other hypotheses not noticed. All more or less only variations on the nebular hypothesis. 71 Necessity for more particular examination into it.