CHAPTER THIRTEEN "It fell," Rogers murmured. "Was that Toroh's plane, or George's?" Loto did not answer; he stared with set face at the crystal mirror, which was turning purple with the deepening shadows of nightfall. The mountains into which the plane had fallen were a vague silhouette against a sky of stars. "If we could only see over there," Rogers added wistfully. "Is this tower we're looking from now the nearest to the mountains, Loto?" It was the nearest. But Fahn was talking swiftly into a small mouthpiece beside him. "We may be able to see into the mountains," he said in a moment. "We must find out which plane it was. Perhaps Toroh fell and was killed." The anxiety on his face belied the calmness of his tone. His two daughters were out there; possibly one or both had met death in that falling plane. A man entered the cave-room hurriedly, a solitary worker whom Fahn had summoned from another part of the cavern. A youngish man, he wore dark glasses, a black robe and gloves. Fahn questioned him briefly; he brightened, nodded, and hastened away again. Loto explained: "He's been working on a new invention, Father. We hoped to use it in the war, but now we fear the attack may come before it's ready. There is only one small model constructed--finished today." The man returned with a small mechanism--a black circular disk, an inch thick and two feet in diameter. On it was mounted a cone-shaped lens a foot high. It looked something like a tiny model of the lighthouse lens. An operating mechanism was fastened behind the lens; it was an open box with tiny coils of wire inside. And near this was what looked like a miniature searchlight. Fahn inspected the apparatus. His assistant made some connections, adjusting another mechanism on the table. Then, turning the disk over and holding it in the air above his head, he released it. The thing floated, motionless, its lens-tower hanging downward. The small searchlight also pointed downward and from it a beam of blue-white light struck the cave-floor with a circle of brilliant illumination. Fahn smiled his approval; the young assistant seemed gratified. "It's a development of the communication towers, combined with the levitation dais you saw at the Festival--the apparatus Toroh's brothers tried to steal," Loto said to his father. A moment later the young scientist had disappeared with his flying lens, taking it outside the cavern to release it into the air. Fahn sat at the table with the newly installed mechanism under his fingers. In a few moments the assistant was back, empty-handed; he stood before the now blank crystal mirror with the other men, anxiously watching for the success of his work. "This was greatly used a few centuries ago," Fahn said. He sighed. "Our ancestors knew so much; it is so hard to keep up with them."