"But he's impractical." Marta sat back in her chair. "You were the first to point out the weaknesses of his greenhouse plan. In fact, you were rather vehement about it before the conference. What happened to change your mind?" Chandler didn't answer. Instead, he stared disinterestedly at the snowy moonlit peaks distorted by the curvature of the transparent tubeway walls. Marta touched his arm. "I don't mean to get personal," she said. "But you seem to have changed a great deal quite suddenly. You're colder, as if you had lost your sense of humor somehow." Chandler met Marta's gaze. "In a way, I suppose I did." "Paul," she started to say, but Professor Kotenko strode down the aisle and plopped into the seat on the other side of Chandler. "I'm afraid these were the best cigars they had in the lounge," he said, holding one out for Chandler. "They'll do," Chandler said. The two men lit up. Kotenko, through a haze of blue smoke, started picking at Chandler's brain like a surgeon undertaking an exploratory operation. "Now then, my dear Dr. Chandler, what will this magic drill be?" "I was thinking of super-dense metals from Pluto and, maybe later, from the depths of the Earth itself." "You are thinking in terms of conventional drilling?" "I have been, yes." Kotenko settled back in his chair, his bull neck against the padded head rest. "I don't wish to insult your intelligence by asking if you have any idea of the pressures at those depths." Chandler rolled his cigar in his fingers but said nothing. "The drill cores we've removed from the crust under the Pacific bear out our mathematics on pressures," Kotenko continued. "But heat is something else again. There will be hot pockets, semi-molten strata, finally molten material of great density. We can only guess at the temperatures. Your drill casing must not only stand up against fantastic pressures but also temperatures that will make the toughest alloys run like quicksilver." "There have been lab experiments removing heat-conductivity entirely from metals," Marta offered. "What is to keep the pressure from blowing the casing right out of the molten rock?" Kotenko asked. "Pressure traps built into the solid strata wherever we find it," Chandler said. Kotenko digested this thought for a moment. "Then your drilling must be fully automated and not physically directed from the surface." "It can be done," countered Chandler. "And I suppose you will use some sort of thermocouple or heat transfer pump to direct the heat against the ice." * * * * * Chandler nodded. "And pump it into the air to raise the mean temperature in the glacial areas." "That will cause some unusual weather aberrations," mused Kotenko. "Nothing that the weather control boys can't handle." "Are you sure," said Kotenko, drawing on his cigar, "that the core of the Earth is made of molten metal?" "I've been working on that assumption."