“On my return five hundred years later to the same place I found it occupied by the sea; on the shore stood a group of fishermen, of whom I asked at what period the land had been covered by the ocean. ‘Is that question worthy of a man like you?’ they replied; ‘this spot has always been such as you see it today.’ “At the end of five hundred years I returned again, and the sea had disappeared. I inquired of a solitary man whom I encountered, when this change had taken place; and he gave me the same reply. “Finally, after an equal lapse of time, I returned once more, to find a flourishing city, more populous and richer in monuments than that which I had at first visited; and when I sought information as to its origin, its inhabitants replied: ‘The date of its foundation is lost in antiquity. We do not know how long it has existed, and our fathers knew no more of this than we do.’” How this fable illustrates the brevity of human memory and the narrowness of our horizons in time as well as in space! We think that the earth has always been what it now is; we conceive with difficulty of the secular changes through which it has passed; the vastness of these periods overwhelms us, as in astronomy we are overwhelmed by the vast distances of space. The time had come when Paris had ceased to be the capital of the world. After the fusion of the United States of Europe into a single confederation, the Russian republic from St. Petersburg to Constantinople had formed a sort of barrier against the invasion of the Chinese, who had already established populous cities on the shores of the Caspian sea. The nations of the past having disappeared before the march of progress, and the nationalities of France, England, Germany, Italy and Spain having for the same reason passed away, communication between the east and west, between Europe and America, had become more and more easy; and the sea being no longer an obstacle to the march of humanity, free now as the sun, the new territory of the vast continent of America had been preferred by industrial enterprise to the exhausted lands of western Europe, and already in the twenty-fifth century the center of civilization was located on the shores of Lake Michigan in a new Athens of nine million inhabitants, rivalling Paris. Thereafter the elegant French capital had followed the example of its predecessors, Rome, Athens, Memphis, Thebes, Nineveh and Babylon. The wealth, the resources of every kind, the great attractions, were elsewhere. In Spain, Italy and France, gradually abandoned by their inhabitants, solitude spread slowly over the ruins of former cities. Lisbon had disappeared, destroyed by the sea; Madrid, Rome, Naples and Florence were in ruins. A little later, Paris, Lyons and Marseilles were overtaken by the same fate.