"I did no more than the others," I told him: "But you know of the enemy's coming then? You know that already the European Federation cities are on their way?" He nodded. "They and the Asiatic Federation's cities from the westward, Brant," he said: "And we are awaiting them here--awaiting them with a chance at least, thanks to you four--to strike back at them when they come. And already they are near--by the map here you can see--" And he turned toward the great table-map upon which was depicted the whole of the earth's surface, the red circles upon it denoting as before the position of the air-cities that hung above it. Now, however, all the circles of the American Federation cities were massed together south of the white outline of the Great Lakes, hanging motionless as the cities around us were hanging motionless. Away to the east on the map, though, just moving in from the Atlantic over the eastern coast, there was creeping across the map another mass of red circles, moving slowly toward our own, that represented the great gathered cities of the European Federation that were rushing westward toward us. And in from the Pacific was creeping a similar mass of a hundred little red circles that were, I knew, the Asiatic Federation's cities. From east and west they were moving, there on the map, moving even as the cities they represented moved through the air, automatically showing their positions and progress. This was accomplished, I knew, by means of special batteries of cruiser-finders, tuned and trained to detect the great electrostatic-motors of air-cities, and recording instantly thus whenever those cities moved with their great electric fields. Their records were carried through complicated mechanical calculators which plotted the exact positions and movements of the cities; and these calculators, in turn, were connected to small special projectors set beneath the great ground-glass table-map, casting upward upon it the red circles of the air-cities. Thus those red circles moved upon the map, even as the great air-cities moved across the world.