"In simple words, the rock is drawn into the bottom something like air into a jet engine," said Chandler. "The rock is vaporized and expelled out the top where the vapor together with the device itself presses the molten material into the walls of the shaft. Because the rock has had its heat conductivity removed, it hardens and remains permanently solid. A tubular force field keeps the shaft from collapsing." "I understand that much." The reporter took out a folded square of paper and a pencil. "But what makes the thing go?" "It has a gravity drive, giving it many times its normal weight." Marta Neilson had moved up to Chandler's elbow. "It simply sinks toward the center of the Earth like a pebble sinking in a pond of water." "What is your reaction to Senator Caldwell's remark that the administration is at last returning all of the nation's gold into a hole in the ground?" Chandler laughed. "Don't get me mixed up in politics." "Are you disturbed by the Interplanetary Council of Churches' charge that any attempt to stop the glacier is defying the will of God?" "Nor religion, either, please." "Then maybe you'll discuss your own field," the reporter said. "Are you aware of the petition signed by thousands of African and Middle Eastern scientists?" "I've read about it," Chandler admitted. "Do you feel that taking an X-bomb into the center of the Earth is completely safe?" "Nothing is completely safe." Chandler pointed to the reporter's feet. "The ground may give way under your feet right now, but I'd bet my life that it won't." The reporter studied the ground under his feet, then scribbled a few words on his paper. A moment later, he spotted Kotenko and excused himself. Marta gave Paul's hand a firm squeeze and he squeezed back. Dr. White stepped up and offered his congratulations, adding the suggestion that perhaps now they should turn their attention to destroying the Bering Strait Dam. Chandler parried the question and the Englishman left to exchange pleasantries with the Indian delegate, who was engaged in an animated conversation with several committee members. "Well," said Marta, smiling up at Chandler, "tomorrow's the big day." "Worries me," Chandler said. "You mean the composition of the core?" Chandler nodded at the drill. "Basically, that thing is an X-bomb. If fusion were to occur in the core and that core _were_ made up of compacted hydrogen atoms, I think the Earth might crack apart along the fault lines surrounding the Pacific Ocean basin." "What could cause fusion?" Marta asked. "Losing control from the surface." "How do you mean?" "Well, it'll tax the abilities of the controllers every minute," Chandler explained, "to compensate for variations in density and gravity. If that thing got away from them, even for a few moments, its velocity could build to a point where it would hit the center of the Earth's gravity at the speed of a meteor."