He started down, then hesitated. The tangly stuff was still clinging to him. He automatically started to brush it off, and noted that it consisted of thin, springy spirals of plastic and metal--identical with the shavings from an old-style, presubtronic hyperlathe. Presumably a huge heap of the stuff had been vented from the funnel-mouths he had passed in his fall. Though it bewildered him to think how many hyperlathes must be in the dark building he was skirting, to produce so much scrap. Hyperlathes were obsolete, almost a curiosity. And to gather so many engines of any sort into one building was unthought of. * * * * * His mind was jarred off this problem by sight of his hands and clothing. They seemed strange--the former pallid, thin, heavy-jointed, almost clawlike. Sharp but far away, as if viewed through a reducing glass, came memories of the evening's events. Clawly, the symchromy, the old man in black, the conference in the Sky Room, his plunge through the forest. There was something clenched in his left hand--so tightly that the fingers opened with difficulty. It was the small gray sphere he had stolen at the Yggdrasil. He looked at it disturbedly. Surely, if he still had that thing with him, it meant that he couldn't have changed. And yet-- His mind filled with a formless but mounting foreboding. Under the compulsion of that foreboding, he thrust the sphere into his pocket--a pocket that wasn't quite where it should be and that contained a metallic cylinder of unfamiliar feel. Then he ran down the terrace, pushed through the straggly hedge, and joined the crowd surging along the blue-litten avenue. The foreboding became a tightening ball of fear, exploded into realization. That other Thorn had changed places with him. He was wearing that other Thorn's clothing--drab, servile, workaday. He was inhabiting that other Thorn's body--his own but strangely altered and ill-cared-for, aquiver with unfamiliar tensions and emotions. He was in the world of his nightmares. He stood stock-still, staring, the crowd flowing around him, jostling him wearily. His first reaction, after a giant buffet of amazement and awe that left him intoxicatedly weak, was one of deep-seated moral satisfaction. The balance had at last been righted. Now that other Thorn could enjoy the good fortunes of utopia, while he endured that other Thorn's lot. There was no longer the stifling sense of being dominated by another personality, to whom misfortune and suffering had given the whiphand. He was filled with an almost demoniac exhilaration--a desire to explore and familiarize himself with this world which he had long studied through the slits of nightmare, to drag from the drifting crowd around him an explanation as to its whys and wherefores. But that would not be so easy.