The thought which must strike us most in our retrospective contemplation is that at that time the _Earth did not exist_. Not one of those human beings who live now, who will live in the future, or who have lived in the past, were then thought of. Nothing of all that now exists around us existed then. Yet in those ancient worlds which have disappeared long ago, the humanities which animated them had their vivid history, with flourishing cities, fights and struggles, laws and law-courts, judges of spiritual things, historians, economists, politicians, theologians, literary men, who took pains to tell the true from the false and to write down conscientiously what they, too, called “universal history.” For them, all creation stopped in their era and in their place; for all of them, creation was finished; the rest of the universe and of limitless eternity was lost in insignificance in comparison with what they called the “Present.” They never thought of the eternity which had already passed before them, nor of the eternity which would come after them. They lived, learned or ignorant, famous or obscure, rich or poor, opulent or miserable, religious or sceptical, they all lived as if their era would never come to an end. Some of them, without losing a minute, amassed a fortune which their heirs hastened to dissipate; some spent their time in dreams and contemplations without thinking of the morrow. In one place there would be battalions inflaming the populace with their patriotic shouts; in another loving couples united their souls in mystery. Under the pressure of what they believed to be affairs of imperative importance, driven by the attractions of pleasure or borne on the wings of ambition, the inhabitants of that ancient world, like those of ours, flung themselves into the whirlpool of life. They, like ourselves, had days of glory and of sorrow; they had their ’89 and ’93, their Austerlitz and Waterloo, and political drama had its 18th Brumaire and its 2nd of December. Thus recently on our own Earth shone the life of Babylon, of Thebes, of Memphis, of Nineveh, of Carthage, the glory of Semiramis, Sesostris, Solomon, Alexander, Cambyses, and Cæsar; and to-day the silence of funeral solitude reigns supreme over the ruins of the palaces and temples, in the slumber of the invading night. In the history of the universe it is not only peoples, kingdoms, and empires which have disappeared, but it is whole worlds, groups of worlds, archipelagoes of planets, visible universes! For eternity did not _begin_, it was never begun. The forces of Nature have never been inactive. For Nature itself, our measures of time, our conceptions of duration, do not exist. She has no past and no future, but a perpetual present. She remains immutable throughout her incessant manifestations and transformations. We pass away; She remains.