I could glimpse Marnick standing there erect, arms folded, peering haughtily down at us. Naturally a tall man, he always seemed taller and more forbidding in that posture. His hair was gray, but no grayer than his face; and against that grayness his eyes were dull black and quite expressionless, as if at one time he had seen some sight that had burned them out. But now his arms unfolded and he leaned tensely forward. His thin colorless lips twitched as if in disbelief. A second later his rasping voice went bounding about the walls: "You! Earthman, over there! Get back to your work!" He was speaking to McGowan and we all knew it. McGowan stood only a few feet from me, but I dared not even glance up at him now. I glimpsed him, however, bending down slowly, deliberately, and I saw his right hand seize a good-sized lump of radite ore from my pile. He straightened just as deliberately, turned to face Marnick and then said: "Go to hell!" With those words, McGowan drew back his hand and hurled the radite lump at Marnick's cage. * * * * * All of us in that moment paused to watch, and all of us were aghast at McGowan's futile bravado. We knew that not even an atom-blast, much less a lump of rock, could penetrate that mysterious force-barrier Marnick had erected around himself. That's what made the act so terrible, for McGowan knew it, too. And he wore a satisfied little smile as he did it. [Illustration: _Straight at the glittering machine McGowan hurled the heavy boulder._] The rock didn't come within a yard of Marnick's cage. It struck against the violet force-halo, bounded back and clattered to the floor. Marnick's lips split into what might have been a grin; he touched a button beside him and the cage dropped the rest of the way to the cave floor. Its door opened and the two Jovian brutes stepped quickly out. Grinning through thick, blubbery lips, with huge powerful hands reaching out, they strode purposefully toward McGowan. McGowan made no defensive gesture. He stood there still smiling a little, as though hugely satisfied with what he had done. The Jovians seized him ungently, hurried him back to the cage and into it. The door closed and the cage slowly began to rise. The Jovians released his arms then, and McGowan acted with customary deliberateness as his right fist lashed up and crashed into Marnick's mouth. Marnick staggered back, his face a gushing well of red; but with a seeming flick of the wrist his paralyzer tube was in his hand, its pale beam spurting out. McGowan sank down in a huddled little heap, but even so, his very attitude as he lay there unconscious seemed one of satisfaction. The cage rose swiftly up and out of sight.