From this time on, the girders became his abode. His weasel face, nearly hidden by the long growth of hair, peered down at them from odd angles with alert suspicion. He resembled an unkempt monkey clad in tattered shirt and trousers. If they attempted to approach or tried to lure him down, he shrieked and chattered at them, and retreated to more precarious heights, until they desisted, fearful of making him fall. "Hunger'll bring him down," DuChane said. And it did. During one of the sleep periods, he raided the store room and created such havoc that Maw Barstow formed a habit of leaving his ration of food and water on a box in plain sight. When all were apparently asleep, he would stealthily slip down and snatch the food, wolfing it like a wild creature, ready to scamper for safety at the slightest noise. Watching from concealment, Marlin saw him do this a couple of times, but made no effort to trap him. And for Marlin, there were more important concerns. Isolated from the rest, he sat for hours at a time before the periscope, trying to arrive at some theory regarding their position in space. One thing was established by now. The sphere had developed a lazy rotation of its own, presenting its two hemispheres alternately to the sun and giving the surface on which the periscope projected a "day" of about five hours. Even without visual observation, the shifting heat areas within the globe would have led to the same conclusion. The clay-like coating seemed to have the property of diffusing the sun's rays throughout its mass. Possibly it would have been burned to a crisp on one side without such rotation. The side which was receiving the direct rays radiated a gentle heat through the walls, and this area of radiation traveled slowly around the circumference. To Marlin, this rotation seemed to deny the activity of the anti-gravity plates, yet the maintenance of gravity indicated that at least they retained some of their function. To account for this seeming paradox and others, he evolved a set of theories. Some he was able to verify. From the first, he had found it difficult to swallow DuChane's surmise that gravity was maintained within the sphere through some mysterious reaction from the obverse surfaces of the repulsion plates. To satisfy his doubts, he wormed his way through a narrow opening between the hull and girders supporting the superstructure, until he reached the edge of a segmented bank of repulsion plates. He found them heavily insulated on the upper side, as if to prevent the force from exerting its full strength in that direction. By lying in a cramped position, he was able to extend an arm through a narrow crevice and to touch the under side of the plates. * * * * *