"You mean that you've learned how to fly, you black imp of Satan?" shouted Jim. And Cain, as if understanding, nodded and beamed all over his black face. With that Jim's idea was born. If the Drilgoes would follow him, he would lead them against Atlantis. And, before the assault began, he would fly to the great Eye that guarded it, and blind it. * * * * * He thought afterward that it was like a supernatural revelation, this scheme, that leaped full-fledged into his brain. And Cain had developed extraordinary executive ability. Outside the cave, through rifts in the swirls of fog, Jim could see innumerable Drilgoes massing in the valley, as if they understood Jim's purpose. From Cain's gesticulations, and the number of times he rubbed his stomach, it was evident that he counted upon sacking Atlantis and was imagining innumerable meals of fat captives. Each flash of lurid light from the volcano disclosed further masses of Drilgoes, armed with their stone spears, apparently assembling for the attack. Whether Tode had summoned them before the Atlanteans offered him the rulership of the city, or whether Jim's own plan had been communicated to them by some telepathic process, it was impossible to guess, but there was not the least doubt but that they were prepared to follow him. Cain nudged Jim and began strapping the other pair of wings about his body. Jim saw that the energy was supplied by two tiny, lights burning in the base, cold fire, stored energy whose strength he did not guess. For, when Cain took him by the hand, and motioned to him to slide the knob in the groove, he was hurled skyward like a rocket. There followed a delirious hour. Tossing and tumbling like a pigeon in a gale, Jim by degrees acquired mastery over the apparatus. At the end of the hour he could fly almost as well as Cain, who, like a black guardian angel kept beside him, reaching out a hand when he overbalanced, and pulling him out of aerial side-slips. * * * * * Suddenly Cain motioned toward the volcano, and started toward it in a rocketlike swoop. Jim understood. The Drilgoes were ready for the attack upon Atlantis. Jim dropped to earth, ran back into the cave, and picked up the rifle and the carton of ammunition. He filled the magazine, and, with the rifle on his arm, rose into the air again. Cain was circling back, uttering weird cries of distress at finding his master absent. "It's all right, Cain," said Jim. "I'm here." Side by side they flew steadily toward the base of the great cone, which was pouring out a fan-shaped stream of fire. Rumblings shook the earth; it was evident that another upheaval was in course of preparation. The long column of the Drilgoes could be seen, extending around the flank of the mountain. Then of a sudden the Eye opened. And across the causeway came the blue-white Ray, carrying death and destruction.