All of that day the fleet raced on, while, in the time-car, Lantin slowed our pace to keep beside them. Sunset came, an arctic sunset, with a crimson globe of fire falling down behind the boundless steppes of ice, suffusing the sky with a glare like blood. Abruptly Lantin uttered a low exclamation, seized binoculars and gazed north through the window beside him.
I sprang to his side, and when he handed me the glasses I saw, far ahead, a little cluster of black dots that stood out jet-black against the crimson sunset. But already Kethra too had seen them, and a score of cars leaped forward from the main body of the fleet, in pursuit, our own time-car among them.
We flashed up toward them, and they grew in size, resolved themselves into air-boats much like those around us. As we neared them, they turned and fled north. Two of them, much swifter than the others, were out of sight almost in a second, safely beyond our pursuit, but the others, seven in number, saw that escape was impossible, so they turned to fight.
For a moment, the fight was on their side, for they turned quite unexpectedly and raced straight toward us, in a solid mass. Lantin's hands flashed over the controls and our car slanted up above the onrushing seven with the speed of lightning, but as it did so a blue flash leapt from the foremost of them and barely missed us.
The air-boats behind us were not so fortunate, for as the streaks of blue light from the enemy touched them, four plunged down to the ice, in flames. The seven attackers, unscathed thus far, passed under them in a swooping dip, turned, and came racing back for another blow.
But now the surprize of our forces was gone, and they struck back. A sudden sound smote our ears, even in the time-car, a low thrumming sound that rose in pitch higher and higher. I could see the men on our air-boats pointing blunt-nosed metal objects toward the oncoming cars of the enemy, and abruptly the significance of it struck me, and I understood that they were using the sound-ray Kethra had mentioned.
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."