57. Spirals in other Departments of Nature: 367 Foraminifer 58. Ditto ditto Nautilus 367 59. To illustrate a Theorem in the 369 Attraction of Gravitation 60. First Law of Motion exemplifies Constant 375 Moment of Momentum 61. A useful Geometrical Proposition 376 62. Acceleration of Moment of Momentum 376 equals Moment of Force 63. Moment of Momentum unaltered by 380 Collision ------------------------------------------------------------------------ THE EARTH’S BEGINNING. CHAPTER I. INTRODUCTION. The Earth’s Beginning—The Nebular Theory—Many Applications of the Theory—The Founders of the Doctrine—Kant, Laplace, William Herschel: Their Different Methods of Work—The Vastness of the Problem—Voltaire’s Fable—The Oak-Tree—The Method of Studying the Subject—Inadequacy of our Time Conceptions. I TRY in these lectures to give some account of an exceptionally great subject—a subject, I ought rather to say, of sublime magnificence. It may, I believe, be affirmed without exaggeration that the theme which is to occupy our attention represents the most daring height to which the human intellect has ever ventured to soar in its efforts to understand the great operations of Nature. The earth’s beginning relates to phenomena of such magnitude and importance that the temporary concerns which usually engage our thoughts must be forgotten in its presence. Our personal affairs, the affairs of the nation, and of the empire—indeed, of all nations and of all empires—nay, even all human affairs, past, present, and to come, shrink into utter insignificance when we are to consider the majestic subject of the evolution of that solar system of which our earth forms a part. We shall obtain a glimpse of what that evolution has been in the mighty chapter of the book of Nature on which we are now to enter.