A colossal city, speeding through earth's atmosphere! Awed, despite ourselves, Hilliard and I clung at our window there as with all else in the city we sped on. A colossal city five full miles in its diameter, with all its works and streets and giant batteries of heat-guns, and rushing above earth at a velocity seeming almost unattainable! And even as we watched, we felt the great city slanting upward with the same terrific speed, climbing swiftly upward until the air about us was all but freezing and then diving down toward earth once more on a long, gliding swoop! Then it had turned in mid-air, was flashing back over its course, was going through maneuver after maneuver until at last the great hissing from its base ceased, and it hung at its former height above the earth once more, the crowds in its towers surging forth now to renew their excited shouts. Last Preparations Hilliard and I gazed for a long moment at each other. "The tube-propellers they were putting in--finished--," he said slowly, "And Berlin ready now for the great attack--" "And all the other European Federation cities," I said, "and all those of the Asiatic Federation--all must be nearly completed now, their new tube-propellers installed also. And in two more days----" In two more days! It was the thought that beat hammer-like in my brain and in Hilliard's in those hours that followed, those hours that were now closing down, one by one, upon the doom of ourselves and of all our nation. Two more days! Two more days at the end of which would have ended the fortnight of our imprisonment, when would come for us the death that had loomed larger and larger during each of those passing days. Two more days at the end of which the great air-cities of the European and Asiatic Federations would rush like whirlwinds over the oceans toward our own slow-moving and helpless cities, to beat them down with all the thunder of their giant batteries. Two more days!--and at the end of them for us and for all the great air-cities and all the millions of the American Federation, doom! It is not to be wondered at, therefore, that in the following hours, Hilliard and I felt close about us the intense despair that ever since the ill-fated attempt of Connell and Macklin had surrounded us. Through all that night following the first demonstration of the immense speed of the air-city, we sat awake, listening to the great shouts of triumph and exultation that came dimly up to us from the crowds that remained in the streets far beneath. The European Federation, we knew, already felt the glow of imminent victory that this new speed of their great air-cities would give them, and were exultant at the chance to annihilate completely the hated American Federation. And, to accomplish that, the very last great preparations were going on now in every part of the air-city.