n the torture chamber Dex wavered slowly back to consciousness to get the growing impression that he was being immersed in a bath of liquid fire. Burning, intolerable pain assailed him with increasing intensity as his senses clarified.

At last he groaned and opened his eyes, for the moment not knowing where he was nor how he had come to be there. He saw strange torture instruments and tall monstrosities with pumpkin-shaped heads surrounding him closely in a semicircle, and staring at him out of great, dull eyes.

Remembrance came back with a rush, and he gathered his muscles to spring at the hateful figures. But he could not move. At waist and throat, at wrists and ankles, were hoops of metal. He closed his eyes again while the burning waves of invisible fire shot through him recurrently from head to foot.

Dully he wondered that he was still alive. His last recollection had been of the Rogan leader pointing his shock-tube full at him, his shapeless countenance working with murderous fury. However, alive he was; and most unenviably so!

His hands, circumscribed to a few inches of movement by the bonds on his wrists, felt the smooth substance at his back. And with a thrill of horror he realized his position: he was crucified against the metal slab on which the slave had writhed in agony a short half hour ago.

Again he strained and tugged, vainly, to get free. Off to one side, pressed back against a huge glass experimental tank, he saw the beautiful Greca, her eyes wide with horror; and caught her frantic pleading message to her "Great White One."

he Rogan leader, squealing and grimacing, advanced toward the victim on the metal plate. One of the long arms went out and a sucker-disk was pressed to Dex's cheek. Dex quivered at the loathsome contact of that soft and slimy substance; then set his jaws to keep from groaning as the disk was jerked away, to carry with it a fragment of skin and flesh.

Gingerly, the tall leader felt the twitching, blackened stump of his blasted arm. Dex grinned mirthlessly at that: he'd struck one or two blows in his own defense, anyhow!

At sight of the Earthman's grin, an expression of defiance and grim joy that needed no interpreting to be understandable, the Rogan leader fairly danced with rage. His long arm went out to the switch beside the plate, and pulled it down another notch—just a little, not nearly to the current that had torn at the slave.

At the increased torment resulting from that slight movement of the regulating lever, Dex yelled aloud in spite of all his will power. It seemed as though his whole body were about to burst into self-generated flame. Every cell and fiber of him seemed on the verge of flying apart. He could feel his eyes start from his head, could feel every hair on his scalp stand up as though discharging electric sparks.

A minute or two of that and he would go mad! He cried out again, and twisted helplessly in his bonds. And then the terrible torture stopped.

The Rogan had not touched the switch—yet whatever sort of current it was that charged the plate was abruptly clicked off, as though someone at a distance had cut a wire or thrown a master-switch.

imultaneously with its ceasing, an invisible, crushing sea seemed to envelope everything. Dex felt his body sag against his metal bonds as if it had been changed to lead.

Before him the Rogans, who had been crowding closer to watch gloatingly each grimace he made, shot doorward as though their pipe-stem legs had been swept from under them. The leader fell on the stump of his seared arm and, a deafening squeal of rage and pain came from his little mouth. His tube fell from his grasp and rolled over the floor half a dozen yards away from him.

Amazed, observing the stricken creatures only dimly through a haze of pain, Dex saw them struggle vainly to get up again, and heard them chattering excitedly to themselves. For the moment, in the face of this queer phenomenon, the prisoner seemed to be forgotten. And Dex was quick to seize the momentary advantage.

"Greca!" he called. "The tube! There—on the floor!"

The girl raised her head quickly, and followed his imploring gaze. Laboriously she started for the tube. At the same instant the Rogan leader began to feel around him for his lost weapon. Not finding it, he raised his head and glanced about for it. He saw the girl making her way toward it and, with a squeak of terror, began to crawl toward it himself.

e was not quick enough. The girl, though not nearly as active under the increased pull of gravity as a person of Earth might be, was yet more agile than the Rogans. And she was the faster mover in this tortuous, snail-like race. While the Rogan leader was still several feet away, she retrieved the shock-tube.

"Kill him!" begged Dex. "And all the rest of the filthy creatures!"

With feminine horror of the thing that faced her, Greca hesitated an instant—a hesitation almost long enough to be fatal. Then, just as the Rogan leader was reaching savagely out for her, she leveled the tube at him and turned it to its full power.

One last thin squeal came from the Rogan's mouth, a squeal that cracked abruptly at its height. What had been its gangling body drifted up in inky smoke.

"The others!" called Dex. "Quick! Before they get their weapons—"

Greca swept the death-tube in a short arc in front of her, over the bodies of the remaining Rogans, as if spraying plants with a hose. One after another, toppling in swift succession like grotesque falling dominoes, the creatures sagged to the floor and melted away. That one small part of Jupiter's red spot, at least, was cleared of Rogan population.

ong shudders racked Greca's body, and her lips were a bloodless line in her pallid face. But she did not go into womanly hysterics or swoon at the slaughter it had been her lot to inflict. Moving as quickly as she could, she went to the metal slab and began, with shaking fingers, to undo the fastenings that held Dex prisoner.

"Good girl," said Dex, patting her satiny bare shoulder as he stood free again. "You're a sport and a gentleman. You don't understand the terms? They're Earth words, Greca, that carry the highest praise a man can give a woman. But let's get out of here before another gang comes and takes us again. Where can we hide?"

"I don't know any hiding places," confessed Greca despairingly. "The Rogans swarm everywhere. We will be seen the moment we try to leave here."

"Well, we'll hunt for a hole, anyway," said Dex. He essayed to walk. What with the tendency of his muscles to jerk and collapse with the aftermath of the torture he had endured, and the sudden and inexplicable increase in gravity that bore him down, he made heavy going of it. "First we'll go up and get Brand."

"Yes, yes," said Greca, a soft glow in her clear blue eyes. "Let us go quickly."

She started toward the door, panting with the effort of moving. But Dex halted an instant, to stoop and pick up another of the tubes.

"We might as well have one of these apiece," he said. "You've proved you have the grit to use one; and maybe the dirty rats will think twice about rushing us if we each have a load of death in our hands."

hey made their way out of the torture laboratory, and up the incline to the street level. And it was just as they reached this that the burden of gravity under which they staggered was lifted from their shoulders as quickly as it had descended on them.

Dex raised his arms just in time to fend his body from a collision with the wall in front of him. "Now what!" he exclaimed.

Greca lifted her hand for silence, inclined her head, and listened intently. As she did so, Dex heard the same noise her quick ears had caught an instant before his: a distant pandemonium of ringing gongs and siren shrieks, and squealing cries of a multitude of agitated Rogans.

"What the devil—" began Dex. But again Greca raised her hand to silence him, and listened once more. As she listened, her sea-blue eyes grew wider and wider with horror. Then, frantically, she began to race down a long corridor away from the street door.

Dex hastened to follow her. "What is it?" he demanded, when he had caught up to her flying little feet. "This is not the way up to the room where Brand—"

"Your friend is not there," she interrupted. She explained swiftly, distractedly: "From the shouts of the Rogans I learn that he got into the great dome building, somehow, and then was driven into the pen of the...."

Dex could not get the next term she used. But her telepathic message of the peril she mentioned formed in his mind clearly enough.

He got a flashing brain picture of a great, high-walled yard with a monster in it of the kind he had caught a close-range glimpse a short while before. Also, he saw a blurred, tiny figure, running from wall to wall, that was Greca's imagining of Brand and his efforts to escape the enormous beast.

"Good heavens!" groaned Dex. "Penned in with one of the things they showed me while I was stretched on the rack! Are you sure, Greca?"

She nodded, and tried to run faster. "This way," she gasped, turning down a passage to the left that ended in a massive metal door. "This leads to the enclosure. Oh, if only we can be in time!"

Her slim fingers tore at a massive bolt that secured the door. "Here," said Dex, wrenching it open for her. And they stepped out into thin sunlight, onto a hard surface of reddish ground that was crisscrossed with innumerable rounded furrows like the tracks old-fashioned, fifty-passenger airplane wheels used to make on soft landing fields.

reca shrieked, and pointed to the far end of the enclosure. Down there, flattened against the wall of the dome building, was Brand. And waddling toward him with a tread that caused the ground to quiver, was a mate to the hideous creature the Rogans had used to terrify Dex in the torture chamber.

Dex leveled the tube he was carrying, swore, hit it frenziedly against his hand. "How do you work this damned thing, Greca—Oh! Like that! There—see if that puts a sting in your hide!"

The distant monster stopped its advance toward Brand. A raw white spot as big as a dinner plate leaped into being on one of its enormous hind legs. It whirled with an ear-splitting hiss, to see what thing was causing such pain in its rear. The frightful head whipped back at the end of the long neck, to nuzzle at the seared spot. Then the giant lizard turned toward Brand again.

A second time Dex pressed the central coil that formed the handle of the tube, as Greca had showed him how to do. A second time the ray shot down the field to flick a chunk of flesh weighing many pounds from the monster's flank. And this time it definitely abandoned the quarry behind it. With a scream like the keening of a dozen steam whistles, it charged back over its tracks toward the distant pigmies that were inflicting such exasperating punishment on it.

Dex swept the tube before him in a short half-circle. A smoking gash appeared suddenly in the vast fore-quarters of the monster. It stopped abruptly, its clawed feet plowing along the ground with the force of its momentum. An instant it stood there. Then, with its head swinging from side to side and lowered so that its looped neck dragged on the reddish, dusty ground, it began to back away from the source of its hurt, bellowing and hissing its rage and bewilderment.

"Brand!" shouted Dex. "This end! Run, while I hold the thing off!"

Brand began to race down the long enclosure, ten feet to a leap. The great lizard darted after him, like a cat after an escaping mouse; but a flick of the tube sent it bellowing and screaming back to its corner.

"Dex!" gasped Brand. "Thank God!"

For a moment he leaned, white and shaken, against the wall. Then Greca caught his hand in both of hers, and Dex put his arm supportingly around his shoulder. They retreated back through the doorway behind them, and slid the bolt across the metal door.