However, nothing could be quieter than this journey through the atmosphere, whose currents had grown weaker with the evening. Beyond the rustling of the blades of the screws there was not a sound, except now and then the whistle from some terrestrial locomotive, or the calling of some animal. Strange instinct! These terrestrial beings felt the aeronef glide over them, and uttered cries of terror as it passed. On the morrow, the 14th of June, at five o’clock, Uncle Prudent and Phil Evans were walking on the deck of the “Albatross.” Nothing had changed since the evening; there was a lookout forward, and the helmsman was in his glass cage. Why was there a look-out? Was there any chance of collision with another such machine? Certainly not. Robur had not yet found imitators. The chance of encountering an aerostat gliding through the air was too remote to be regarded. In any case it would be all the worse for the aerostat—the earthen pot and the iron pot. The “Albatross” had nothing to fear from the collision. But what could happen? The aeronef might find herself like a ship on a lee shore if a mountain that could not be outflanked or passed barred the way. These are the reefs of the air, and they have to be avoided as a ship avoids the reefs of the sea. The engineer, it is true, had given the course, and in doing so had taken into account the altitude necessary to clear the summits of the high lands in the district. But as the aeronef was rapidly nearing a mountainous country, it was only prudent to keep a good lookout, in case some slight deviation from the course became necessary. Looking at the country beneath them, Uncle Prudent and Phil Evans noticed a large lake, whose lower southern end the “Albatross” had just reached. They concluded, therefore, that during the night the whole length of Lake Erie had been traversed, and that, as they were going due west, they would soon be over Lake Michigan. “There can be no doubt of it.” said Phil Evans, “and that group of roofs on the horizon is Chicago.” He was right. It was indeed the city from which the seventeen railways diverge, the Queen of the West, the vast reservoir into which flow the products of Indiana, Ohio, Wisconsin, Missouri, and all the States which form the western half of the Union. Uncle Prudent, through an excellent telescope he had found in his cabin, easily recognized the principal buildings. His colleague pointed out to him the churches and public edifices, the numerous “elevators” or mechanical, granaries, and the huge Sherman Hotel, whose windows seemed like a hundred glittering points on each of its faces. “If that is Chicago.” said Uncle Prudent, “it is obvious that we are going farther west than is convenient for us if we are to return to our starting-place.” And, in fact, the “Albatross” was traveling in a straight line from the Pennsylvania capital.