The huge, windowless buildings that housed the massive uranium piles were a mile beyond. But no one went near those tremendous atomic piles. Everything in them had to be handled by remote control by the few technicians in Headquarters Building who kept them operating. "Mart, isn't it queer nobody ever thought of usin' bismuth instead of uranium, before now?" Norris asked, out of his roseate glow. "Scientists too c'nservative, that's the trouble," Kincaid answered wisely. His voice soared. "We're about to launch a new epoch! No more uranium shortage to worry 'bout! No more politicians botherin' the Project!" "And I'll be able to fix up old M-Fifty and run him myself again," added Doug Norris. He choked up once more. "When I think of that Proxy that was like a brother to me, lyin' down in that lonely fissure with the Raddies gloatin' over him--" "Don't think about it, Doug," begged Kincaid, with tender sympathy. "Soon's we get these atomic piles changed around, we'll go back and get good old M-Fifty up again and fix him good as new." * * * * * That promise cheered Norris' grieving mind. He got out and helped Kincaid carry the heavy lead cylinder into Headquarters Building. The technicians they passed in the lower rooms saw nothing surprising in the two Project men staggering along under the weight of the cylinder. Nor did Petersen and Thorpe, at first. Petersen and Thorpe were the two technicians on duty in the big, sacred inmost chamber of controls. Visors here gave view of every part of the distant, mighty atomic piles--the massive lead towers that enclosed the graphite and uranium lattices, the gas penstocks that led to giant heat turbines, the gauges and meters. And the banks of heavy levers here could switch those lattices, make any desired change in the piles, without the necessity of a man entering the zone of dangerous radiation. Petersen had surprise on his spectacled, scholarly face as he greeted the two scientists. "I didn't know you had another uranium consignment for us," he said. Kincaid helped Norris place the lead cylinder in the breech of the tube that would carry it mechanically to the distant pile. "This isn't uranium--it's better than uranium," Kincaid announced impressively. "What do you mean, better than uranium?" Petersen asked in a puzzled tone. He opened the end of the lead cylinder. "Why, this stuff is bismuth! What is this, a crazy joke?" Young Thorpe had been staring closely at Kincaid and Norris. "They're both plastered!" he burst out. Kincaid drew himself up in an unsteady attitude of outraged dignity. "Tha's what thanks we get," he accused thickly. "We come here to make a won'erful improvement in your blasted old atomic piles, and we get insulted." "Thorpe," Petersen said disgustedly, "get them out of here, and ... _Look out!_"