saw him and came running to let them in.
A dozen of the transports had already taken off half-loaded. One of them had come crashing back with a shot through it. Unarmed, the convoys were helpless against the attackers.
The Valiant carried only a handful of men. Dane prayed that Margo had left the ship, but as the take-off gravity riveted them to the floor, he saw her in the doorway of the bridge.
From the first, the men in the warship knew there was something amiss. Instead of a fleet, they discovered only one Earth-craft in the sky, and it was in full retreat. Thankful that the bombing was at least temporarily over, Dane was yet mystified by the lay of things.
The attacking ship was small. It dodged, spiralled, sprinted, to keep out of the path of the Valiant's guns. And every minute the two ships were drawing closer to Jupiter. The sky-giant's gravity seized them like the tentacles of an octopus. They were hurtling into the Red Spot, and still the Earth-ship fled on.
"There are gold uniforms in the quartermaster's room," Vanz shouted. "Everyone who isn't wearing one, get into a suit right now. "We're coming into the danger zone."
Margo left to find a uniform, so that only Dane, Kris, and the Warlord were on the bridge. Vanz motioned Dane to the Chief Gunner's post.
"We're closing the gap," he told him. "Be ready with that bow cannon."
Like a huge, red Grand Canyon, a thousand miles long and hundreds wide, the Red Spot shot its ragged walls up around them. It was like diving headfirst into hell. What looked like flames, but was actually some form of radiation, shimmered on the pitted surface of the walls. The Earth-ship was roaring along one wall, dodging in and out of escarpments and massive outcroppings. Kris whistled.
"Look at those madmen!" he jerked. "If they brush one of the rocks, they'll have such an explosion as we've never seen. That's nothing but pure concentrate!"
Now the ship was pulling out into the void, sinking deeper into the bottomless hole. Vanz grunted: "Line her and give her all you've got!"
Dane saw the stern of the ship weave into the middle of his sights. He pressed the firing button. Nothing happened, except that their quarry pivoted and started back at them.
"Fire that gun!" Nile Vanz shouted. "Didn't you hear me,"
Dane's reply was a rough whisper.
"I heard you. But—the guns are dead!"
IT CAME to Kris first, the thing that had happened.
"The concentrate, Vanz!" he jerked, "It—it won't work in the presence of all the concentrate around us. You drop an iron bolt in between two powerful magnets, and it will hang there. That's what's happening here. The very air is charged with resistance."
"That can't be," Dane objected. "Why would the ship's motive power continue if the guns are dead? Aren't they practically the same thing?"
"No. The ship uses the concentrate more as a catalyst. The other elements in the mixture keep us going."
The discussion ended abruptly, as a shell exploded within feet of them and sent them wallowing toward the wall. Kris sent the ship straight up in a climb that would take them put of range of the attackers.
But the little pursuit was faster. It was curving around ahead of them in a matter of seconds. Kris was forced to dodge and weave to keep out of the
