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 weighed 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 t