landing stage to the rocks below. The guards from the ethership, he saw, remained behind on the platform and there were new guards awaiting him below. Husky fellows, these were, in strange bulky clothing and armed with the highest powered dart guns. The other prisoners from the vessel were already down there, a huddled and frightened mass—a squashed pile, almost—silent now and watchful of their jailers.

"

Come on, show some speed, tough guy!" a guard yelled from the foot of the runway. "Think this is a reception?"

Another of the guards guffawed hoarsely, and Luke choked back the blasting retort that rose in his throat. Plenty of time yet before he'd be ready to make things hot for those birds.

The runway, he observed, was a strip of yielding metal that glowed faintly with an unnatural greenish light. He was nearing its lower end when the siren of the ethership shrieked and he heard the clang of the outer door of its air-lock as it swung to its seat.

Then he stepped out to the smooth stone slab on which the nearest of the guards was standing. Immediately it was as if a tremendous weight was flung upon him, bearing him down until his knees buckled beneath him. He was rooted to the spot by an enormous force which dragged at his vitals and weighted his limbs to leaden uselessness. With a mighty effort he raised his head to look up into the grinning yellow face of the guard, and his thick neck muscles were taut gnarled ridges under the strain.

"Damn your hide!" he howled. "It's a trick. I'll break you in two for this, you slob!"

His huge biceps tensed and his fists came up. But they came up slowly and ineffectually, ponderous things he could scarcely lift. A great roaring of rocket tubes was in his ears then, and the ethership screamed off through the red mists while he dabbed futilely at the leering yellow face. And vile curses rasped from between his set teeth at the laughter of the guards.

Luke Fenton never had taken the trouble to learn or he would have known something about this planet Vulcan on which he was a prisoner. As far back as 1859, by Earth chronology, its existence within the orbit of Mercury had been reported by one Lescarbault, a French physician. But other astronomers had failed to confirm, in fact had ridiculed his discovery, and it was not until some years after the establishing of interplanetary travel in the first decade of the twenty-first century that the body was definitely located.

Vulcan, the smallest and innermost of the planets, circles the sun with great rapidity at a mean distance of twenty million miles. Its periods of rotation and revolution are equal, so that it always presents the same face toward the solar system's great center of heat and light—for which reason one side is terrifically hot and the other, that facing into outer space, unbearably cold.

There is no life native to the body, and mankind has found it possible to exist only in the narrow belt immediately on the dark side of the terminator, the line of demarcation between night and day. Here there are the dense vapors, illuminated perpetually by refracted light from the daylight side and by the internal fires of the planet itself, fires which erupt at regular intervals through many fissures and craters. And it is only under greatest hardship that man can exist even here, what with the noxious gases and the extremes of heat and cold to which his body it subjected. There is no natural source of water or of food, so these essentials must of necessity be conveyed from Mars or Earth by ethership.

In spite of all this, man has persisted in establishing himself in the vapor belt of Vulcan for the sake of wresting from the rocky soil its vast deposits of rare ores, and a great number of mining operations are continually in progress. All of these are commercial projects and are worked by adventurous seekers of fortune, save only the penal colony known as Vulcan's Workshop: But no Terrestrial or Martian, however greedy for riches, would dare to remain longer than two lunar months, which is the average time limit of human endurance. Only the condemned remain, and these remain to die.

Though hardly more than two hundred miles in diameter, Vulcan is possessed of a surface gravity almost six times greater than that on Earth. This is due to the planet's core of neutronium, the densest known substance of the universe, a little understood concentration of matter whose atoms comprise only nuclei from which all negative electrons have been stripped by some stupendous cataclysm of nature.

And so it was that Luke Fenton, uninsulated from the tremendous gravity pull when he stepped from the charged metal of the runway, was struggling against his own bodily weight, suddenly increased to more than twelve hundred pounds.

Doggedly, the Earthman pitted his mighty sinews against the force he could not understand. Here was an intangible thing, yet it was a power that challenged his own brute strength, and he exerted himself to the limit in accepting the challenge. With legs spread wide and with sweat oozing from every pore, he heaved himself erect, straightening knees and spine and standing there firmly on his two feet.

"He's carrying it!" came the husky whisper of a guard. "This bird is tough."

Craftily, Luke bared his white, even teeth in a good-humored grin. He had seen what they were doing with the other prisoners, fitting them one by one with the strange bulky breeches—garments that gave forth a faint greenish glow like that of the runway. And each of the men, so attired, was enabled somehow to get to his feet easily and walk about as if unhampered by the force which had flattened him to the rocks and which still held Luke's straining body in its grip.

The yellow-skinned guard, a Terrestrial of Asiatic origin, was solemnly engaged now in lacing the slitted legs of a similar garment to Luke's rigid nether limbs. Yet there was no cessation of that awful weight when the thing was done. The guard stepped back and leered wickedly. He had slung his dart gun over his shoulder and now produced a slender black tube which he leveled at Luke's midsection.

"You walk now, Fenton," he snarled.

The Earthman rose upward as if he would leave the ground. Two or three inches seemed added to his stature, and his muscles trembled from the sudden release. He stepped a pace forward.

Then a light beam flashed forth from the black tube and Luke sagged down with an astonished oath squeezed grunting from his throat. The swift renewal of the inexplicable force had caught him off balance and he dropped ignominiously to his knees.

"Ha!" gloated the Oriental. "It is thus we control the tough ones, Fenton. I've given you a warning; now get up—and march!"

On the last word came blessed release and the return of Luke's strength. He marched, meekly falling in with the file of new prisoners. He even smiled through the red stubble of his beard. But black hatred was in his heart, and renewed determination that he'd get away from this place somehow—alive.

Time would show him the way.

Fenton's slow but retentive mind absorbed many things during the succeeding few days. There was neither day nor night in this hellish place—only the flame-lit mists; but they had clocks like those of Earth, and you worked fourteen hours on the slope or in the smelter and had the rest of each so-called day of twenty-four hours in which to eat and sleep.

The food was coarse, but there was plenty of it. There was only water to drink, lukewarm stinking stuff, doled out sparingly in rusty tin cups. And, during the sleeping periods, you were required to take off the gravity-insulated garments and sleep in huts with insulated