Contact with many "sorts and conditions of men" brings home the need of ceaselessly dinning into their ears the fact that _Darwin's theory deals only with the evolution of plants and animals from a common ancestry. It is not concerned with the origin of life itself, nor with those conditions preceding life which are covered by the general term_, Inorganic Evolution. Therefore, it forms but a very small part of the general theory of the origin of the earth and other bodies, "as the sand by the seashore innumerable," that fill the infinite spaces. We have seen that speculation about the universe had its rise in Ionia. After centuries of discouragement, prohibition, and, sometimes, actual persecution, it was revived, to advance, without further serious arrest, some three hundred years ago. A survey of the history of philosophies of the origin of the cosmos from the time of the renascence of inquiry, shows that the great Immanuel Kant has not had his due. As remarked already, he appears to have been the first to put into shape what is known as the nebular theory. In his General Natural History and Theory of the Celestial Bodies; or an Attempt to Account for the Constitution and the Mechanical Origin of the Universe upon Newtonian Principles, published in 1775, he "pictures to himself the universe as once an infinite expansion of formless and diffused matter. At one point of this he supposes a single centre of attraction set up, and shows how this must result in the development of a prodigious central body, surrounded by systems of solar and planetary worlds in all stages of development. In vivid language he depicts the great world-maelstrom, widening the margins of its prodigious eddy in the slow progress of millions of ages, gradually reclaiming more and more of the molecular waste, and converting chaos into cosmos. But what is gained at the margin is lost in the centre; the attractions of the central systems bring their constituents together, which then, by the heat evolved, are converted once more into molecular chaos. Thus the worlds that are lie between the ruins of the worlds that have been and the chaotic materials of the worlds that shall be; and in spite of all waste and destruction, Cosmos is extending his borders at the expense of Chaos." Kant's speculations were confirmed by the celebrated mathematician, Laplace. He showed that the "rings" rotate in the same direction as the central body from which they were cast off; sun, planets, and moons (those of Uranus excepted) moving in a common direction, and almost in the same plane. The probability that these harmonious movements are the effects of like causes he calculated as 200,000 billions to one.