Simultaneously with man the planet also had been transformed. Industry had produced mighty but ephemeral results. In the twenty-fifth century, whose events we have just described, Paris had been for a long time a seaport, and electric ships from the Atlantic, and from the Pacific by the Isthmus of Panama, arrived at the quays of the abbey of Saint Denis, beyond which the great capital extended far to the north. The passage from the abbey of Saint Denis to the port of London was made in a few hours, and many travellers availed themselves of this route, in preference to the regular air route, the tunnel, and the viaduct over the channel. Outside of Paris the same activity reigned; for, in the twenty-fifth century also, the canal uniting the Mediterranean with the Atlantic had been completed, and the long detour by way of the Straits of Gibraltar had been abandoned; and on the other hand a metallic tube, for carriages driven by compressed air, united the Iberian republic, formerly Spain and Portugal, with western Algeria, formerly Morocco. Paris and Chicago then had nine million inhabitants, London, ten; New York, twelve. Paris, continuing its growth toward the west from century to century, now extended from the confluence of the Marne beyond St. Germain. All great cities had grown at the expense of the country. Agricultural products were manufactured by electricity; hydrogen was extracted from sea-water; the energy of waterfalls and tides were utilized for lighting purposes at a distance; the solar rays, stored in summer, were distributed in winter, and the seasons had almost disappeared, especially since the introduction of heat wells, which brought to the surface of the soil the seemingly inexhaustible heat of the earth’s interior. But what is the twenty-fifth century in comparison with the thirtieth, the fortieth, the hundredth! Everyone knows the legend of the Arab of Kazwani, as related by a traveller of the thirteenth century, who at that time, moreover, had no idea of the duration of the epochs of nature. “Passing one day,” he said, “by a very ancient and very populous city, I asked one of its inhabitants how long a time it had been founded. ‘Truly,’ he replied, ‘it is a powerful city, but we do not know how long it has existed, and our ancestors are as ignorant upon this subject as we.’ [Illustration: THE CHINESE CAPITOL. ] “Five centuries later I passed by the same spot, and could perceive no trace of the city. I asked a peasant who was gathering herbs on its former site, how long it had been destroyed. ‘Of a truth,’ he replied, ‘that is a strange question. This field has always been what it now is.’ ‘But was there not formerly a splendid city here?’ I asked. ‘Never,’ he answered, ‘at least so far as we can judge from what we have seen, and our fathers have never told us of any such thing.’