The seven air-boats rushed on toward our own, and I had a flashing glimpse of their decks, crowded with armored guards and with a few of the brilliant-robed Kanlars directing them. Blue flashes leapt again from the seven, and two more of the air-boats of Kom cometed down in bursts of fire, but now, as the seven dipped again under the air-boats of the Khluns, the thrumming, high-pitched sound increased sharply in intensity, and I saw five of the seven Kanlar cars literally break up into small pieces and fall, tumbling down toward the ice-fields below them in a shower of men and small pieces of metal. It was the power of sound, which causes a steam-whistle to shake a house to its foundations, a thousand times amplified by the apparatus devised by the men of Kom. The remaining two air-boats of the Kanlars attempted to flee, but in a moment they too broke up and fell, as the men of Kom altered the vibration-frequency of their apparatus to affect the two remaining cars. Behind us, now, the great main fleet of our air-boats was coming up, and there was a short halt in midair. Kethra's air-boat swept up beside us, and I opened the door in the top of our time-car, and stood up to hear him. "Those were scouts," he cried to us, "a patrol of the Kanlars' air-boats. And two got away! They'll warn the Kanlars of our coming." "But what do you intend to do?" I asked. "You'll not give up the attack?" "No!" he shouted. "We'll go on, and meet them if they come out. But there will be no surprize now." "But what of our friends?" I asked. "We were to rescue them from the pit." "We'll send an air-boat for them," he said. "It can speed up to the city of cylinders, and since the Kanlars will come down to meet us now, it can sink down into the shaft you spoke of without interference, and get your friends. I will need you with me, to guide us to the city of Kanlars, in case their fleet doesn't come out to meet us." And so we swiftly decided. At an order from Kethra, an air-boat slanted up toward us and hung beside us. We gave the pilot of it, and his two assistants, precise information that would enable them to reach the temple and get down to the pit, where they could rescue our comrades from the roof-top where they would be awaiting us. The pilot was instructed to race up toward the city of cylinders in a wide circle, to avoid meeting any of the Kanlars' air-boats, and when the city was deserted by guards and Kanlars, as we were confident it would be, he could easily penetrate to the temple and the pit. He promised to carry out our instructions faithfully, and sped away into the gathering dusk toward the northwest. * * * * * Night was falling now, and with an order from Kethra, the fleet again began to move, speeding toward the north, but going warily now, with a fringe of swift scouts flying above and far ahead, and with Kethra's car and our own soaring at the point of the fleet's triangular formation.