There was something very distinctive about the way the two eyed each other. No one could have said just when it started, but by the time they were facing each other across the control table, it was very plain; the look of two men come to fight a duel. Clawly's face hardened. His gaze seemed to concentrate. His duplicate started, as if at a slight unexpected blow. For an instant he grinned unpleasantly, then his face grew likewise grim. Neither moved. There was only that intense staring, accompanied by a silent straining of muscles and a breathing that grew heavy. But none of those who watched doubted but that an intangible duel was being fought. Conjerly, frowning, stepped forward. But just then there grew a look of sudden desperate terror in the contorted face of Clawly's black-clad duplicate. He staggered back a step, as if to avoid falling into a pit. An unintelligible cry was wrenched out of him, and he snatched at his holster. But even as he raised the weapon, there flashed across the first Clawly's features a triumphant, oddly _departing_ smile. XIII. Yggdrasil shakes, and shiver on high The ancient limbs, and the giant is loose; Elder Edda In the black, cramping tunnel Thorn could only swing his knife in a narrow arc, and the snarl of the attacking dog was concentrated into a grating roar that hurt his eardrums. Nevertheless, knife took effect before fangs, and with an angry whimper the dog backed away--there was no room to turn. From the receding scuffle of its claws Thorn could tell that it had retreated almost to the beginning of the tunnel. He relaxed from the crouch that had put his back against the rocky roof, sprawled in a position calculated to rest elbows and knees, and considered his situation. Of course, as he could see now, it had been an inexcusable blunder to enter the tunnel without first building a fire to insure his being able to get back to a place from which he could use his slingshot. But coming down the ravine he hadn't seen a sign of the devils, and there was no denying it had been necessary to revisit the cave to see if Thorn III had any extra food, weapons, or clothing stored there. The need for food was imperative, and yesterday he and Darkington had completely failed in their hunting. He wondered if Darkington would attempt a rescue. Hardly, since it would be late afternoon before the gnarled little man returned from his own hunting circuit. With night coming on, it was unlikely that he would risk his life venturing down into the ravine for the sake of a man whom he believed to be half-crazy. For Thorn had tried to tell him altogether too much about alternate worlds in which Civilization had not perished. Darkington had dismissed all this as "the dreams," and Thorn had shut up, but not until he realized he was forfeiting all Darkington's confidence in him as a hard-bitten and realistic neo-savage.