prisoners made sleepy sounds. A relief guard took station, and the ship became silent, so that one could hear the rumbling of the propelling rockets. As there were no ports in this hold, there was no light whatever except the faint glow that came from the central passage above the platform. Against this the pirate was outlined as he sat on his stool. As Quirl's eyes became accustomed to the darkness he could see the play of faint highlights on his muscular torso, and so he waited.

He thought over the situation. The safest and easiest course would be to create such a disturbance that Captain Strom would be attracted to the scene. This would probably not involve anything more than a severe beating for himself, and he would then find opportunity to acquaint Strom with the projected mutiny somehow. That Strom would know how to deal with it he never doubted. Lenore might then still be forcibly impressed as a citizen of Strom's new planet, but at least she would not be exposed to the infinitely worse fate of becoming the plaything of Gore and his villainous crew.

The flaw of this plan was that Quirl himself would still be under practical sentence of death. Strom would not let his gratitude carry him so far as to release a man who knew as much as Quirl did, and who would not promise to keep his secrets.

The preferable, though far more dangerous course was to strike before the mutineers could. Quirl knew something about the structure of the ship. It was built around the tubular passage, and every hold or group of rooms opened on this well, from the bow where the navigators were to the stern where the rockets were located. Somewhere there would be a generating room where the invisibility field was being produced. If he could find this and wreck the generators one of the I.F.P. ships with which this part of space doubtless swarmed, would sight them, and after that everything was in the hands of fate.

Quirl nervously waited for the guard to nod. At any moment he expected to hear a hellish bedlam break loose—the beginning of the mutiny. And the guard seemed alert. There was nothing to do but take a chance.

Quirl sighed as if he were turning in his sleep, so that the clink of the released chain would not seem out of place. The guard did not stir. Slowly, very slowly, Quirl crept across the floor. He had been robbed of all his clothing except his torn silk trousers; and his boots were gone, so he was able to move as quietly as a cat.

With tense silence he ascended the ladder, praying that his weight would not send up a warning vibration. But his luck held. He was nearly at the top before it broke.

"Take him off! Take him off!" It was an eery, strangled shriek from one of the male prisoners in the throes of a nightmare. With a startled curse the guard thudded to his feet, peered tensely into the darkness, his weapon sending twin milky beams of the powerful ionizing ray toward the source of the sound.

The dreamer had awakened, still gasping in the grip of fear, and other disturbed sleepers were grumbling.

"Better go easy, you fools," the pirate warned them. "Yer just in luck that I didn't let loose a couple bolts on ye. Got a good notion to do it, anyway." He played the dangerous little spots of light around, amused as the prisoners scrambled for safety, but with no real intention of releasing the deadly electric charge along the paths provided for it. This cruel pleasure cost him his life. As he turned his back Quirl leaped. His iron-hard forearm rose and fell, and the edge of his hand came down on the back of the pirate's thick neck. There was a muffled crack and he slumped to the platform grating.

Quickly the officer stripped off the man's harness and buckled it around his own naked chest. The electrogun had been uninjured, and hooked to the belt was also the riot club, a truly appalling thing at close quarters. Quirl carried the body down, laid it prone in the corner he had occupied, snapped on the waistlock, and threw a ragged old blanket over the hairy legs. In the forthcoming disturbance, if anyone looked in, he would think the inert form a sleeping prisoner, and that the guard had deserted post.

Quirl had feared an outbreak among the prisoners, but they were so apathetic that they paid little attention. Perhaps they thought it was Quirl who had been killed, and he did not dare even a whispered farewell to the girl he knew was watching somewhere in the darkness.

Much to Quirl's delight, the long, tubular passage was deserted. Here the centrifugal gravity was less than it had been in the hold. A weird place, this central tube, where every direction was down, and a man could walk on his ceiling, his floor, his walls with equal facility. No top nor bottom—just a long, smooth tube with numerous enigmatic doors leading to—where?

At least it was easy to tell where the bow of the ship was. A light shone through a transom over the door to the navigating room. Should he try to hold up the navigating officer? He decided against that. There would be at least three men in there, and it was the custom to keep those quarters locked.

"If only I knew where they generate the invisibility field!" he muttered, as he stood irresolute.

Opportunity came at that moment. A crack of light appeared along the passage. A door was opening there. A moment later a head and shoulders showed. Someone was climbing up. Swiftly the officer ran to the place. The pirate did not even suspect anything wrong until he felt the spots of milky light on his face. He showed his terror plainly.

"Get up!" Quirl hissed. The man obeyed with alacrity. Quirl glanced down. He saw tiers of bunks, evidently one of the crew's dormitories.

He now turned to the cowering pirate.

"I'd as soon kill you as not!" Quirl snarled.

"You got me wrong, brother!" the pirate whined. "I'm with Gore in this deal. Lay off!"

"Where you bound for?"

"I have to relieve Burke at the ventilating turbines."

"Let Burke wait. Lead on to the invisibility generators."

"Oh, I can't do that, mister! I got to have a pass. Say, mister, I was just kidding about being one of Gore's men. I'm for the cap'n, yes, sir!"

"You lying scum!" Quirl barked impatiently. "Get going!"

The white-faced and bewildered pirate led the way down the tube to the after end. He unlatched a door and tried to enter, but as soon as he had dropped through to the platform he was met by a guard with leveled ionizer.

"This gem'man," he started to explain. But Quirl dropped after him and gave him a powerful shove, so that he crashed into the guard. The latter pulled the trigger, and the unfortunate pirate crashed over the platform's edge to the floor. Quirl had out his own electrogun and dispatched the guard. At the same time he felt a stunning shock. His senses reeled, but the grating had taken part of the discharge loosed by a pirate electrician at the foot of the ladder. Quirl threw his riot club and followed that up with another lightning bolt.

He was then the only living person in the room, in which two generators hummed softly. Connected to them was a bank of U-shaped tubes, each as tall as a man, which were filled with silent livid fire. Quirl picked up a wrench and started hammering at the thick tubes until the glass cracked. Each time he was engulfed by a wave of heat, and the tube became black. The great generators idled and automatically came to a stop. Quirl was certain now that the pirate ship would be visible, but the position of the captives was still desperate. He hoped that none of the surviving pirates would think of calling at the generator room, or find out in some other way that they were now visible in the eternal day of space.

Quietly he climbed back to the passage and closed the hatch. He cast about for his next move. He was looking toward the bow, but on hearing the subdued clink