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.
His exploring fingers contacted a fragment of some sort—a pebble or hardened lump of clay. Detaching it from the surface, he fingered it exploringly. When his fingers relaxed, the lump escaped and instantly snapped back to the plate, as if held by a taut rubber band. He recovered the fragment and tried the same thing experimentally, with the same result.
There was no mistake. Objects released below the anti-gravity plates dropped toward them, just as did objects released from above. If anything, the attraction of the underside was stronger. In point of fact, the supposed anti-gravity plates were gravity plates.
Convinced of something he had vaguely suspected, Marlin retired to his usual vantage point—the observation scaffold—to think matters out.
He was vaguely disturbed when Sally clambered up the ladder and joined him.
"You're up to something?" she accused. "Tell Sally what it's all about."
"I'd only bore you."
"What's the difference? I'm bored anyway."