propelled by rockets! The terrific acceleration carried it out of their range of vision in an instant, and as Arcot swung the ship to bring him again within sight of the windows, they gasped, for already he was many miles away.
There was a terrific wrench as Arcot threw on all the power he dared, then quickly leveled the machine, following the pirate at lightning speed. He increased the acceleration further as the men grew accustomed to the force that weighted them down. Ahead of them the pirate was racing along, but quickly now they were overhauling him, for his machine had wings of a sort! They produced a tremendous amount of head resistance at their present velocity, for already the needle of the radio speedometer had moved over to one mile a second. They were following the fleet plane ahead at the rate of 3600 miles an hour. The roar of the air outside was a tremendous wave of sound, yet to them, protected by the vacuum of the double walls, it was detectable only by the vibration of the car.
Rapidly the pirate's lead was cut down. It seemed but a moment before he would be within range of their machine gun. Suddenly he nosed down and shot for the ground, ten miles below, in a power dive. Instantly Arcot swung his machine in a loop that held him close to the tail of the pirate. The swift maneuvers at this speed were a terrific strain on both men and machines-the acceleration seemed crushing them with the weight of four men, as Arcot followed the pirate in a wide loop to the right that ended in a straight climb, the rocket ship standing on its tail, the rocket blast roaring out behind a stream of fire a half mile long.
The pirate was climbing at a speed that would have distanced any other machine the world had ever seen, but the tenacious opponent behind him clung ever tighter to the tiny darting thing. He had released great clouds of his animation suspending gas. To his utter surprise, the ship behind him had driven right through it, entirely unaffected! He, who knew most about the gas, had been unable to devise a material to stop it, a mask or a tank to store it, yet in some way these men had succeeded! And that hurtling, bullet-shaped machine behind! Like some miniature airship it was, but with a speed and an acceleration that put even his ship to shame! It could .twist, turn, dive, rise and shoot off on the straight-away with more flashing speed than anything aloft. Time and again he tried complicated maneuvers that strained him to the utmost, yet that machine always followed after him!
There was one more thing to do. In outer space his rockets would support him. In a straight climb he shot up to the blazing sun above, out into space, while the sky around him grew black, and the stars shone in solemn splendor around him. But he had eyes for only one thing, the shining car that was rising with more than equal speed behind him. He knew he must be climbing over two thousand miles an hour, yet the tracker came ever closer. Just out of sighting range for the machine gun now ... in a moment ... but, she was faltering!
The men in the machine behind sat white-lipped, tense, as the whirling shocks of sudden turns at terrific speed twisted the gyroscopic seats around like peas in a rolling ball. Up, down, left, right, the darting machine ahead was twisting with unbelievable speed. Then suddenly the nose was pointed for the zenith again, and with a great column of flame shooting out behind him, he was heading straight toward space!
“If he gets there, I lose him, Morey!” said Arcot. The terrific acceleration of the climb seemed to press them to their seats with a deadly weight. It was labor to talk-but still the car ahead shot on-slowly they seemed to be overhauling him. Now that the velocities were perforce lowered by the effects of gravity, and the air resistance of the atmosphere was well nigh gone, only the acceleration that the human body could stand was considered. The man ahead was pushing his plane ahead with an