He stopped, that goading doubt torturing his mind, that chilling, unvoiced fear that Blaine's mysterious invention might prove a failure.
The huge black top of the domed meteorite-mountain loomed slowly out of the shimmering blue mists, bulking darkly against the starry sky. They pressed toward its base, and were starting to climb up its rough asterium side, when a sound reached their ears. The roar of a ship's rockets tubes!
"Look!” Sual Av yelled frantically, pointing upward. ‘The Gargol."
The Saturnian cruiser was blasting off, rising from where it had been parked beside the Venture, with a reverberating roar of tubes. It shot up at dizzying speed, and disappeared in the dark
"God, Cheerly has got away in it, somehow,” Gunner cried hoarsely.
They scrambled frantically on up the mountain, driven by overmastering fear. When they came to where the Venture lay, they stopped, aghast.
A fight had taken place here. A half-dozen space-suited pirates lay in a scorched, dead heap. Other men in suits were running out from the Venture.
Out of that little crowd sprang a gray beast with blazing green eyes, that limped on a scorched leg as it bounded frantically toward Lana and nuzzled against her. After the space dog came Stilicho Keene, his wrinkled face recognizable through his glassite helmet.
"You brought the lass back!” he cried, joy lighting his faded eyes. Then as his face fell on the glowing forms of Clymer Nison and Chan Ora he gasped, “But who—"
"What happened here? Who was in the Gargol when it took off?” Thorn cried fiercely.
"Cheerly — and that there radite!” groaned the old pirate. “He fooled us, neat. He and his man came up here a half-hour ago, dragging the radite on their sledge. They were wearing suits like yours, ray-proofed and with even the helmets coated, so we couldn't see their faces plain enough. And Cheerly imitated your voice so that I thought he was you, John Thorn!
"He said that he and Sual Av had brought the radite back, and that Gunner was following with Lana. We never suspected him, he imitated your voice so well, and we couldn't even recognize his fat figure in that shapeless suit. He took the radite into the Gargol, saying we'd use the Saturnian ship to return to Earth in. He even went into the Venture for a few minutes, I suppose to see if you'd any papers or secrets worth stealing."
He fell silent.
"Go on, man!” Thorn cried. “How did he get away with the Gargol, when you had its crew under guard?"
"He did it easy,” groaned the old man. “He and his man, posing as you and Sual Av, went into the Gargol. We didn't follow, never suspecting. And Cheerly and his man blasted down our guards in there, set free his Saturnian crew, and took off, with a blast of their guns that killed six of our men!"
"And now he's on his way back to Saturn with the radite!” Gunner cried. “We've got to catch him!"
"We'll catch him. The Venture can overhaul him!” Thorn cried. “Into the ship, all of you! We're blasting off!"
They tumbled into the Venture, leaving the two radioactive men standing staring. Inside the craft, its doors closed, the Planeteers and Lana and Stilicho climbed to the control-room. The old pirate yelled urgently into the interphone.
"Power chambers on!” he ordered.
They heard the clash of the injectors below, and then the rising roar of the power chambers.
A terrific explosion shook the ship next moment. They were all thrown from their feet, and heard cries of pain and terror from below.
"Good God, something's let go!” Gunner yelled,
Thorn led as they hastily climbed down to the stern compartment that housed the four big power-chambers.
The compartment was a wreck. The power-chambers had exploded with frightful force, killing three pirate engineers.
"That damned Cheerly must have done this when he came into the Venture!" a wounded, staggering engineer gasped. “The power-chamber safety was jammed—deliberately jammed!"
"Cheerly's won again, curse him!” Gunner yelled wildly. “It'll take us days to rebuild these power-chambers, if we can do it at all. And by that time he'll be half-way back to Saturn!"
CHAPTER XX
At Uranus’ Orbit
The cruel stars above Erebus looked down upon a scene of strange activity. Out of the dimly shining deserts of that terrible world, out of the shimmering blue hazes that perpetually wrapped its surface, rose the huge black bulk of a rounded metal mountain. And on the top of that mountain, space-suited men who staggered from days of frantic labor were now nearing the end of their toil,
The Venture was being made ready for blast-off. New power-chambers had been built into the ship in the days that had passed. Lacking in inertrum with which to build the new chambers, John Thorn had used the metal of the mountain, the black asterium which was fully as strong as inertrum itself. With atomic furnaces and atomic welding-torches, the Planeteers and Stilicho's pirates had labored almost unceasingly to construct the new chambers. Lana Cain's order had been enough to make the pirates obey Thorn utterly.
Thorn had been torn with almost unbearable apprehension in these days of terrible toil. Each day, each hour, meant that Jenk Cheerly was millions of miles farther toward Saturn with the radite. No one of them all, except Thorn himself, believed there was the slightest chance to overtake the spymaster now,
Gunner Welk and Sual Av, reeling with fatigue, stumbled up to where Thorn was superintending the last preparations.
"All ready, as far as I can see,” Gunner said hoarsely.
Stilicho Keene and Lana came up anxiously as he spoke.
"Boy, are ye crazy to think that you can overtake the Gargol when it's got days’ start of us?” averred Stilicho.
"We'll overtake them,” Thorn said fiercely. “We've got to!"
"But to do it, we'd have to travel three times as fast as any spaceship ever traveled before!” Stilicho exclaimed.
"That's what we're going to do!” Thorn clipped.
They stared at him, as though they believed his mind had been strained by the days of superhuman toil and anxiety.
"We're going to use radioactive matter for fuel in our power-chambers!” Thorn explained. “It will yield several times as much power as ordinary metallic fuel. We can get up to a speed no ship has ever attained before!"
"But no one's ever dared use radioactive fuel before,” Lana whispered, stunned. “It would crumble any power-chamber it was used in."
"You forget we've got asterium power-chambers in the Venture now!"
Thorn cried. “And asterium is proof against radioactivity. The daring originality of Thorn's plan burst upon the others, taking their breath away.
"By heaven, it may work!” Gunner exclaimed excitedly. “If the power doesn't make our rocket-tubes back-blast."
"We'll have to take that chance;” John Thorn said harshly. He turned. “Here come Clymer Nison and Chan Gray now. They volunteered to bring the radioactive fuel we'll need."
The two glowing figures of the radioactive men were coming up onto the top of the metal mountain, dragging after them the asterium sledge. Upon the sledge, in a rudely forged asterium box, was a great mass of shining mineral.
Thorn's quick orders superintended the pirate engineers as they carried the asterium box of minerals into the Venture, and prepared it for use, then Thorn turned to the two radiant radioactive men.
"We're ready to start,” he told Clymer Nison haggardly. “We want you to come back with us, to Earth,"