“I mentioned it only as a possibility,” replied the professor. “The probability is, that if you did learn anything, it would be of no material value, even if you were to be so extremely fortunate as to get back alive with it.” “Nevertheless,” replied Roger, “I’m going up, just on the strength of that possibility.” “Don’t be an utter fool,” warned the professor, but Roger was already calling Bevans. “Have the Blettendorf 800 ready in five minutes,” he said. “I’ll be up in a jiffy.” He dressed rapidly while the professor remonstrated with him. “No use,” said Roger, “I’m going.” “Very well,” replied the professor. “If you must go I’ll go with you. Perhaps the two of us can bring back some information of value—if we get back.” They took the elevator to the top, stepped out on the roof, and battled their way through the driving rain, in which there was beginning to be a hint of sleet, to the electroplane. Eight men held it, just outside the hangar, while Bevans, in the pilot’s seat, tested the motor. The two men entered and took their seats. Then Roger gave the order to ascend. Came a roar from the helicopter blades, and they were off. As they rose above the skyscrapers of Chicago, their craft tossing and careening like a leaf in a gale, Roger took two parcels from beneath the seat, one of which he handed to the professor. “Folding parachutes,” he said. “Bevans is wearing one. Watch how I strap mine on, and do likewise. We may need them.” The wind swept them out over Lake Michigan—then they plunged into a swirling, blinding snowstorm, and everything below, even the powerful guide-lights of Chicago’s great landing fields, vanished. With propeller and helicopter blades roaring, Bevans drove the plane higher and higher, until they at length emerged above the seething, moon-silvered clouds. “No green moonlight here,” said the professor. “But look—look to the southeast!” exclaimed Roger. The professor looked, and saw a green band of light, wide at the bottom, but narrowing as it extended upward straight toward the gibbous moon. “The moon looks green from Washington,” said the professor, “because the inhabitants had to look through the green lights to see it.” Roger shouted an order through the speaking tube. “Hover.” As the big plane, now riding in comparatively calm air, hung smoothly suspended by its helicopter blades, he turned a pair of powerful binoculars on the moon. He focused them, looked for a moment longer, then handed them to the professor. “It’s coming from the ring-mountain, Copernicus,” he said. “Looks as if a beam from an enormous green searchlight were coming directly from the center of the crater.” “So it is,” said the professor, after a careful scrutiny. “From the very center of the crater.”