wiftly Dex was carried down the long ramp to the ground floor, the arms of his captors gripping him with painful tightness. Heading the procession was the immensely tall, gangling Rogan leader, clutching Greca by the wrist and dragging her indifferently along to be his mouthpiece.

They did not stop at the street level; they continued on down another ramp, around a bend, descending an even steeper incline toward the bowels of Jupiter. Their descent ended at last before a huge metal barrier which, at a signal from the leader, drew smoothly up into the ceiling to disclose a gigantic, red-lit chamber underlying the foundations of the building.

In fear and awe, Dex gazed around that huge room.

It resembled in part a nightmare rearrangement of such a laboratory as might be found on Earth; and in part a torture chamber such as the most ferocious of savages might have devised had they been scientifically equipped to add contrivances of supercivilization to the furthering of their primitive lust for cruelty.

There were great benches—head-high to the Earthman—to accommodate the height of the Rogan workmen. There were numberless metal instruments, and glass coils, and enormous retorts; and in one corner an orange colored flame burnt steadily on a naked metal plate, seeming to have no fuel or other source of being.

There was a long rack of cruelly pointed and twisted instruments. Under this was a row of long, delicate pincers, with coils on the handles to indicate that they might be heated to fiendish precision of temperatures. There were gleaming metal racks with calibrated slide-rods and spring dials to denote just what pull was being exerted on whatever unhappy creature might be stretched taut on them. There were tiny cones of metal whose warped, baked appearance testified that they were little portable furnaces that could be placed on any desired portion of the anatomy, to slowly bake the selected disk of flesh beneath them.

ex shuddered; and a low moan came from Greca, whose clear blue eyes had rested on the contents of this vast room before in her capacity as hostage and interpreter for the inhuman Rogans.

And now another sense of Dex's began to register perception on his brain.

A peculiar odor came to his nostrils. It was a musky, fetid odor, like that to be smelled in an animal cage; but it was sharper, more acrid than anything he had ever smelled on Earth. It smelled—ah, he had it!—reptilian. As though somewhere nearby a dozen titanic serpents were coiled ready to spring!

Looking about, Dex saw a six-foot square door of bars in one wall of the laboratory—like the barred entrance to a prison cell. It was from the interstices of this door that the odor seemed to emanate; but he had no chance to make sure, for now the Rogan leader approached him.

"I will first show you," he said, through his mouthpiece, Greca, "what happens to those who oppose our orders. We have a slave who tried to run away into the surrounding jungles three suns ago...."

A man was dragged into the chamber. He was slightly taller and more stockily muscled than an Earthman might be; but otherwise, in facial conformation and general appearance, he might have come here straight from New York City. Dex felt a great pang of sympathy for him. He was so plainly one of humankind, despite the fact that he had been born on a sphere four hundred million miles from Dex's.

The fellow was paralyzed with horror. His eyes, wide and glazed, darted about the torture room like those of a trapped animal. And yet he made no move to break away from the clutch of the two Rogans who held him. He knew he was helpless, that wild-eyed glance told Dex. Knew it so thoroughly that not even his wildest terror could inspire him to try to make a break for freedom, or strike back at the implacable Rogan will.

t a nod from the leader, the man was stripped to the waist. Here Dex started in amazement. The man's broad chest was seamed and crisscrossed by literally hundreds of tiny lateral scars, some long healed, and some fresh incisions.

He was dragged to a metal plate set upright in the wall, and secured to it by straps of metal. Evidently the miserable being knew what this portended, for he began to scream—a monotonous, high-pitched shriek that didn't stop till he was out of breath.

The Rogan leader stared at him icily, then depressed a small lever set in the wall beside him. The plate against which the captive was bound began to shine softly with a blue light. The slave twisted in his bonds, screaming again. Rhythmic shudders jerked at his limbs. His lips turned greenish white. The shudders grew more pronounced till it seemed as though he were afflicted with a sort of horrible St. Vitus dance. Then the tall Rogan pulled back the lever. The slave hung away from his supporting shackles, limp and unconscious.

Dex moistened his lips. An electric shock? No, it was something more terrible than that. Some other manifestation of the magnetic power the Rogans had harnessed—a current, perhaps, that depolarized partly the atoms of the body structure? He could only guess. But the convulsed face of the unfortunate victim showed that the torment, whatever it was, was devilish to the last degree!

"That will be the next to the last fate reserved for you," the Rogan informed Dex, through Greca. "Death follows soon after that—but not too soon for you to see and feel what waits for you behind the barred door!" And he nodded toward the cage-entrance affair, from which came the musky, reptilian stench.

"Now that you have seen something of what will happen to you if you refuse to tell us what we want to know, we shall proceed," said the leader.

e pointed toward one of the gargantuan work benches, and two of the Rogans slid down from it a contrivance that looked familiar to Dex. An instant's scrutiny showed him why it was familiar: it was a partly dismantled atomic motor.

In spite of the ordeal that faced him, Dex felt a thrill of elation as he looked at the motor. In its scattered state, it told a mute story: a story of long and intensive study by the Rogans, which had yielded them no results! Only too obviously, the intricate secret of atomic power had not let itself be solved.

On the heels of the elation that filled his heart, came a sickening realization of his dilemma. He could not have told the Rogans what they wanted to know even if he had wished to! He himself didn't know the principles of the atomic engine. As Brand had remarked, he was no space navigator; he was simply a prosaic lieutenant, competent only at fighting, not at all versed in science.

He knew, though, that it would do no good to assert his ignorance to the Rogans. They simply wouldn't believe him.

"You will rebuild this engine for us," ordered the tall leader, "showing us the purpose of each part, and how the power is extracted from the fuel. After that you will set it running for us, and instruct us in its control."

Dex braced himself. His final moment had come.

By way of indicating his refusal he looked away from the dismantled motor and said nothing. The Rogan repeated his command. Dex made no move. Then the leader acted.

He said something to the Rogan guards who had been standing by all this while, alert against an outbreak from their prisoner. Dex was caught up, carried to one of the metal racks, and thrown down on its calibrated bed. Loops of metal, like handcuffs, were snapped around his wrists and ankles; and a metal hoop was clamped over his throat, pinning him to the torture rack. Resistance would have been useless, and Dex submitted quietly.

he contrivance, with him on it, was wheeled toward the barred door. It was halted at a spot marked on the floor, about thirty feet from the bars. The Rogan leader stepped alongside the rack, with Greca trembling beside him.

Dex closed his eyes for a moment, grimly marshaling strength of will to go through the trial that was just beginning.

The Rogan leader depressed another lever in the rock wall. The barred door slid slowly up, to reveal the receding darknesses of some great cave, or room, that adjoined the laboratory. Dex rolled his eyes so that he could watch the doorway; and, in a cold perspiration, waited for whatever might appear.

It was not long in coming!

The reptilian smell suddenly grew stronger. There was a booming hiss, a savage bellowing. A clattering of vast scales rattled out as some body weighing many tons was dragged over rock flooring. Then, before Dex's staring eyes appeared a huge, wedge-shaped head, at sight of which he bit his lips to keep from crying aloud.

Often enough he had seen one of those terrific heads looming in the fog of the northern hemisphere of Jupiter. He did not know the genus of the vast monster that bore it, but he did know it for the fiercest of the lizard giants that roamed the Jovian jungles. A creature larger than a terrestrial whale, with great long neck and heavy long tail dragging yards behind it, it would find the puny bulk of a man nothing but a morsel in its jaws!

Again the gigantic thing hissed and bellowed. And then its huge head came through the six-foot door and its neck uncoiled to send the gaping jaws within a foot of Dex. There it struggled to reach him, prevented by the small doorway that restrained the bulk of its enormous body, its head only inches away from the cleverly measured spot to which the metal rack had been wheeled.

ex stared, hypnotized, into the dull, stony eyes of the beast, gasping for breath in the stench of its exhalations. The jaws snapped shut, fanning his cheek. He fought for self-control. Steady! Steady! The slimy Rogans had no intention of feeding him to the thing yet. Not till they had made more determined efforts to wring from him the secret of the motor. They were just prefacing actual physical torture with hellish mental torture, that was all.

That he was right in his guess was proved in a few moments. He heard a louder hiss from the great lizard so near him. Opening his eyes, he saw the Rogan leader in the process of forcing the serpentine neck to withdraw foot by foot back into the doorway, using his shock-tube as a sort of distant prod.

The monster swayed its ugly flat head back and forth, hissing deafeningly at the sting of the tube, now and again lunging with its vast unseen body at the too narrow entrance that kept it from entering the laboratory. Dex could hear the foundation walls of the building creak at the onslaught of that tremendous weight.

If it would only break through! he thought savagely. But it wasn't going to. In a short while it was cowed by the deadly tube, and withdrew its head awkwardly from the chamber. The barred door slid down into place: and the Rogan leader once more turned his attention to his prisoner.

"You will be wheeled within reach of the creature as the last step of your fate," Dex was informed. "Meanwhile, we shall start with something less deadly...."

A cogged wheel beside him was turning a notch. Dex felt the sliding bed of the rack crawl slightly under him. Intolerable tension was suddenly placed on his arms and legs. The leader stared at a spring dial; and moved the wheel another notch. The rack expanded again, stretching Dex's body till his joints cracked.

"You will tell us what we want to know," said the Rogan, glaring coldly down at him.

Dex compressed his lips stubbornly. He couldn't tell them if he wanted to, and, by God, he wouldn't if he could.

Another notch, the wheel was turned; and in spite of himself a groan escaped Dex's lips. One more notch, while the metal slide-rods beneath him lengthened a fraction of an inch....