"According to the atlas, the island is barren and deserted," Tom said, "so no friendly power will object if we land there. If it's being used as an enemy base for quake attacks against our country, we have every right to investigate. I might be able to learn the secret of the setup--perhaps even put the equipment out of commission." "Nevertheless, a raid by a United States force could lead to trouble if the base there puts up any resistance," Mr. Swift said gravely. "That's why I intend to handle it myself," Tom declared. "I'll take all responsibility." Tom Sr.'s eyes flashed as he recalled some of his own hair-raising exploits in younger days. "All right, son," he said, putting a hand on Tom's shoulder. "I know I can trust your judgment. Good luck!" Again Tom issued a call for volunteers. Bud, Hank Sterling, Arv Hanson, and Chow were all eager to take part. Within an hour they were taking off for Fearing. At the rocket base, they embarked in the _Sea Hound_, Tom's favorite model of his diving seacopter. A powerful central rotor with reversible-pitch blades, spun by atomic turbines, enabled the craft to rise through the air or descend into the deepest abysses of the ocean. Propulsion jets gave it high speed in either medium. Loaded with equipment, the _Sea Hound_ streaked southward through the skies--first to Florida, then across the Gulf and Central America into the Pacific. Here Tom eased down to the surface of the water and submerged. It was near midnight when the _Sea Hound_ rose from the depths just off Balala. The lonely rocky island lay outlined like a huddled black mass against the star-flecked southern sky. No glimmer of light showed anywhere ashore. "Maybe no one's here," Bud murmured. "Don't bank on that," Tom said. "They wouldn't be apt to advertise their presence to passing ships or planes." Tom nosed inshore as closely as he dared from sonar soundings, finally easing the _Sea Hound_ up to a rocky reef that fingered out from the beach. Then he, Bud, Hank, and Arv clambered out, armed with wrecking tools and powerful flashlights. Chow, in spite of his muttered grumblings, was ordered to stay aboard and guard the ship with the other two crewmen who had come along. Tom led his party cautiously ashore from the reef. They probed the darkness of the beach. Their footfalls sounded eerily in the night silence, broken only by the soughing of the sea wind and splash of breakers. "Good place for spooks!" Bud whispered jokingly. A steep draw led upward among the rocky slopes. A hundred feet on, Tom's group found the black yawning mouth of a cave. The yellow beams of their flashlights revealed a tunnel leading downward inside. Tom checked with a pocket detector. Its gauge needle showed no field force caused by electrical equipment in operation. "Okay, let's go in!" Tom murmured. Cautiously they moved into the tunnel. Then suddenly ahead of them a powerful dazzling light burst on, nearly blinding the searchers! CHAPTER XIX