And westward, upon our western screen, loomed equally gigantic the similar circle of air-cities of the Asiatic Federation. Peking, the third in size of the world's air-capitals, at the center of its cluster of cities rushed at the same smooth speed toward us, with Shanghai and Tokio and Bombay and Rangoon foremost in its circle. From east and west thus the two stupendous circles of cities rushed toward our own, grimly waiting; and, as we watched them, there flashed over me in that tense moment a strange wonder as to the feelings with which one of a hundred years before would have watched this battle. Then I laid aside that passing wonder as the two great circles drew nearer to the range of our great heat-gun batteries. And this, surely, was a spectacle that none had ever seen or dreamed before--this spectacle of the world's mighty cities converging swiftly upon each other in battle to the death! And as strange, too, must have been the sight of us three, sitting there amid our box-like periscopic screens, the heart of the mighty tower's base; yet seeing and directing from there all the great mass of the hundred mighty cities around us. "They're not going to join forces!" I exclaimed: "They're going to strike us at the same moment from east and west!" Yarnall nodded, his eyes intent upon the screens: "Either that," he said, "or--" Armageddon! He broke off suddenly; for at that moment there came to us a giant salvo of thunder from both east and west, a terrific shock of sound that rolled deeply through the air toward us from the two distant armadas advancing! An instant later there was a whistling sound over our own cities, and we knew that a great storm of heat-shells was plunging toward them. A few struck with wild bursting flares across our massed cities, and with their suddenly-released gigantic heat there appeared great craters of fusing, melting metal. The greater part of the shells, though, fell short, whirled down to earth to flash on the ground far below. The range was not yet closed, I knew; and so far our own great cities remained silent as death. Yarnall was watching now with hands clenched tightly, as the two circles from east and west came on. A moment later there rolled from them another great salvo, and another mass of shells rushed toward us; but, though most of these also fell short, a greater number than before flared and fused in melting, searing death upon our own massed cities!