It was a cozy affair, indeed, that Cobb was ushered into--a little, but handsomely furnished room, containing all that one could desire in a thoroughly well-appointed apartment. Electric lamps threw a charming, subdued light over everything in the room, while an electric heater diffused a gentle warmth which was most agreeable this September morning. Retiring to rest, Cobb dreamed of nothing but pneumatic railways, submarine boats, and gigantic convulsions of nature. It was about 7 dial when both Rawolle and Lyman came and awoke their guest, who, after a refreshing bath and a delicious breakfast, ascended to the upper deck of the Tracer. The main deck of the vessel was of very small area amidship, some two feet above the water-line, and inclosed by an iron railing. A beautiful scene presented itself to his view. The Tracer lay about half a mile from the docks of Cairo, and that city was just awakening to its daily round of bustle and activity. The stream was covered with shipping, some at anchor, while others were plying between the city and the opposite shore, a mile and a half away. Sailing craft there were a plenty, but no steamers, though there were many vessels moving swiftly through the water, yet showing no smoke or funnels. This fact was immediately noted by Cobb, and inquiry made of Lyman, who stood near him, as to why there was no smoke visible. "Neither coal nor wood is now used for marine propulsion," replied Lyman. "Lipthalite vapor, or lipthalene, is now the motive power of vessels without sails. I will show you some of this lipthalite, later on, in this vessel." Turning his eyes from the busy and charming scene about him, Cobb's thoughts came back to his immediate surroundings. What was he standing upon? The small, water-flush deck of a metal submarine vessel, the total area of which could not exceed a thousand square feet. A number of peculiar openings, valves, and pipes abutted on the deck, and a single metal mast stood at the bows; but no smoke-stack or other accessories to propulsion were visible. Surveying all these things, he was about to ask information concerning their use, when Lieutenant Sibley, the officer in command, made his appearance, and was introduced to him. "I am sorry I was not aboard to welcome your arrival, last evening, Mr. Cobb," he began, in a courteous and pleasing tone of voice, "but I was detained in Central City, across the river, until early this morning. I hope you slept well, and are ready for the trip to Pittsburgh?" "Not only ready, but anxious for it," was the reply. In a few moments more, by order of the Lieutenant, the anchor was raised, and the Tracer moved up the stream, headed E. ¼ N. As the vessel moved through the shipping, the national colors, which were displayed from its mast, were saluted by the dipping of flags and sounding of whistles.