There, on the third level, he entered a Mecho restaurant, sat down at a table and ordered from the robot waiter, pushing ivory-tipped buttons on the menu before him. He ate leisurely, smoked ferociously, thinking. Looking at his watch, he saw that it was nearly two o'clock. He walked to the cashier machine, inserted the metallic check with the correct change and received from the clicking, chuckling register the disk that would let him out the door. "Thank you, come again," the cashier-robot fluted. "Don't mention it," growled Wilson. Outside the restaurant he walked briskly. Ten blocks away he came to a building roofing four square blocks. Over the massive doorway, set into the beryllium steel, was a map of the Solar System, a map that served as a cosmic clock, tracing the movement of the planets as they swung in their long arcs around the Sun. The Solar System was straddled by glowing, golden letters. They read: INTERPLANETARY BUILDING. It was from here that Spencer Chambers ruled his empire built on power. Wilson went inside. _CHAPTER FOUR_ The new apparatus was set up, a machine that almost filled the laboratory ... a giant, compact mass of heavy, solidly built metal work, tied together by beams of girderlike construction. It was meant to stand up under the hammering of unimaginable power, the stress of unknown spatial factors. Slowly, carefully, Russell Page tapped keys on the control board, setting up an equation. Sucking thoughtfully at his pipe, he checked and rechecked them. Harry Wilson regarded him through squinted eyes. "What the hell is going to happen now?" he asked. "We'll have to wait and see," Russ answered. "We know what we want to happen, what we hope will happen, but we never can be sure. We are working with conditions that are entirely new." Sitting beside a table littered with papers, staring at the gigantic machine before him, Gregory Manning said slowly: "That thing simply has to adapt itself to spaceship drive. There's everything there that's needed for space propulsion. Unlimited power from a minimum of fuel. Split-second efficiency. Entire independence of any set condition, because the stuff creates its own conditions." He slowly wagged his head. "The secret is some place along the line," he declared. "I feel that we must be getting close to it." Russ walked from the control board to the table, picked up a sheaf of papers and leafed through them. He selected a handful and shook them in his fist. "I thought I had it here," he said. "My math must have been wrong, some factor that I didn't include in the equation." "You'll keep finding factors for some time yet," Greg prophesied. "Repulsion would have been the answer," said Russ bitterly. "And the Lord knows we have it. Plenty of it." "Too much," observed Wilson, smoke drooling from his nostrils. "Not too much," corrected Greg. "Inefficient control. You jump at conclusions, Wilson."