And as though the monster heard and understood, it rushed again with all its vast weight and force against the wall in a mad effort to escape the things that were blasting the living flesh from its colossal framework.

This charge was the last. With a roaring crash a section of the building thirty yards across went back and down, leaving the ma.s.sive roof to sag threateningly on its battered truss-work.

It was as though the side of an ant-heap had been ripped away. Inside the domed building hundreds of Rogans ran this way and that on their elongated legs, squealing in their staccato, high-pitched tongue.

With blind fury the mad monster charged in through the gaping hole it had battered for itself. In all directions the Rogans scattered. Then an authoritative tall figure with a tube in each of its four sucker-disks, whipped out a command and pointed to the great coils which lay immediately in the berserk monster's path.

The command restored some sort of order. Losing their fear of the beast in their greater fear of the damage it might do, the Rogans ma.s.sed to stop it before it could demolish the Rogan heart of power.

At this point Brand saw an opening of the kind he had been praying for. The Rogans had retreated before the terrific charge of the monster in such a way that the s.p.a.ce between its vast bulk and the control board was clear.

"After me!" he shouted to Dex. "One of us has got to reach that lever while the creature's still there to shield us!"

The two Earthmen dashed through the jagged hole in the wall and raced to the control board just as the huge lizard, a smoking ma.s.s, sank to the floor. Brand gazed almost fearfully at the lever-slot.

Was there a reverse to the gravity-control action? There was room in the slot for the lever to be pulled down below the neutral point, if that meant anything....

Behind them the great bulk of the dead lizard was disappearing with incredible quickness under the rays of the tubes directed on it. Now the pumpkin-shaped heads on the opposite side were visible through a fleeting glimpse of a skeleton that was like the framework of a skysc.r.a.per. And now the colossal bones themselves were melting, while over everything hung a pall of greasy black smoke.

"Hurry, for G.o.d's sake!" gasped Dex.

Brand threw down the lever till it stuck. At once that invisible ocean poured crushingly over them, throwing them to their knees and sweeping the Rogans flat on their hideous faces just as half a hundred tubes were flashing down to point at the Earthmen.

"More--if you can!" grated Dex, whirling this way and that and spraying the ma.s.sed Rogans with his death-dealing tube. Dozens went up in smoke under that discharge; but other dozens remained to raise themselves laboriously and slowly level their suddenly ponderous weapons at the Earthmen.

Brand set his jaw and threw all his weight on the lever. It bent a little, caught at the neutral point--and then jammed down an appreciable distance beyond it.

Instantly the blue streamers, that had stopped their humming progress from coil to coil with the movement of the switch to neutral, started again in reversed direction. And instantly the invisible ocean pressed down with appalling, devastating force.

Greca and Brand and Dex were flattened to the floor as if by blankets of lead. And the scattered Rogans about them ceased all movement whatever.

"Oh," sobbed Greca, fighting for breath. "Oh!"

"We can't stand this," panted Dex. "We've fixed the Rogans, all right.

But we've fixed ourselves, too! That lever has to go up a bit."

Brand nodded, finding his head almost too heavy for his neck to move.

Sweat beaded his forehead--sweat that trickled heavily off his face like drops of liquid metal.

With a tremendous struggle he got to his knees beneath the master-switch. There he found it impossible to raise his arms; but, leaning back against the control board and so getting a little support, he contrived to lift his body up enough to touch the down-slanting lever with his head and move it back along its slot a fraction of an inch. The giant coils hummed a note lower; and some of the smashing weight was relieved.

"That does it, I think," Brand panted, his voice husky with exhaustion and triumph.

He began to crawl laboriously toward the nearest street exit. "On our way!" he said vibrantly. "To the s.p.a.ce ship! We leave for Earth at once!"

Slowly, fighting the sagging weight of their bodies, the two Earthmen inched their way to the street, helping Greca as they went. Among the sprawled forms of the Rogans they crept, with great dull eyes rolling helplessly to observe their progress, and with feeble squeals of rage and fear and malediction following their slow path.

On the street a strange and terrible sight met their eyes.

Strewn over the metal paving like wheat stalks crushed flat by a hurricane, were thousands of Rogans. Not a muscle of their pipe-like arms or legs could they move. But the gravity that crushed them rigidly to the ground did not quite hold motionless the shorter and more st.u.r.dily built slaves.

Among the thousands of squealing, panting Rogans that lay as though paralyzed on the metal paving, crawled equal thousands of Greca's enslaved people. Their eyes flamed with fanatic hate. And methodically--not knowing what had caused their loathed masters to be stricken helpless, and not caring as long as they _were_ helpless--the slaves were seeking out the shock-tubes that here and there had fallen from the clutch of Rogan guards. Already many had found them; and everywhere gangling, slimy bodies were melting in oily black smoke that almost instantly vanished in thin air.

As it was in these streets and in the great square in the center of which rested the Earthmen's ship, just so, they knew, was it being repeated all over the red empire. Slowly crawling, fiercely exulting slaves were exterminating the tyrannous things that had held them so long in dreadful bondage! Before the sun should set on another flashing Jovian day there would be no Rogan left in the red spot.

"And so it ends," said Brand with a great sigh. He moved over beside Greca, and touched her lovely bare shoulders. They were shaking convulsively, those shoulders; and she had buried her face in her hands to keep from gazing at the ghastly carnage.

Brand pressed her to him. "It's terrible--yes. But think what it means! The knell of all the Rogans been sounded to-day. As soon as the secret of these death-tubes has been a.n.a.lyzed by our science and provided against, my friend and I will return from Earth with a force that shall clear the universe of the slimy devils. Meanwhile, your people are safe here; with the gravity what it is, no Rogan attacking hordes can land."

They crawled tortuously over the square to the s.p.a.ce ship. Brand turned again to Greca; and now in his eyes was a look that needed no language of mind or tongue for its complete expression.

"Will you come to Earth with me, Greca, and stay by my side till we return to set your people in power again?"

Greca shook her head, slowly, reluctantly. "My people need leaders now. I must stay and help direct them in their new freedom. But you--you'll come back with the others from Earth?"

"Try and stop him!" grinned Dex. "And try and stop me, too! From what I know now of the way they grow 'em on your satellite"--his eyes rested on Greca's beauty with an admiration that turned her to rosy confusion--"I'd say I'd found the ideal spot to settle down in!"

Brand laughed. "He's answered for me too. And now, a salute that is used on Earth to express a promise...." He kissed her--to her utter astonishment and perplexity, but to her dawning pleasure. "Good-by for a little while."

The two Earthmen hoisted themselves heavily over the sill of the control room of their ship, and crawled inside.

They secured the trap-door, and turned on the air-rectifiers. Brand moved to the controls, waved to Greca, who was smiling at him through the gla.s.s panel, and pointed the ship on its triumphant, four hundred million mile journey home.