Instantly Tom broke free and landed a hard blow on his assailant's jaw. The man collided with the base of the oscilloscope, and slid down into a sitting position on the floor.
       "Captain Svornin!" Tom exclaimed. "What are you doing in my observatory?"
       The Brungarian slowly stood up. "I came here to look for you," he mumbled. "When I heard running footsteps along the corridor, I thought it was someone about to attack me. I am sorry that I made a mistake."
       As Tom started to say the story sounded fishy, Bud entered the room. "The fire's out in the spaceship. Very little damage," he reported. Seeing Svornin, he added, "Everything's ready for lift-off, Captain."
       "I am very happy to hear it," said the Brungarian, heading for the door.
       "Wait a moment!" Tom commanded. "My ghost log is missing! So are the meteor fragments! You must have taken them! Hand them over!"


       "I do not know what you are talking about!" Svornin growled.
       "Oh no?" Bud countered, moving toward him.
       Quick as a wink, Svornin plunged forward. Seizing Bud's wrist, he gave a judo twist that slammed Bud into Tom, knocking the boys to the floor. Svornin dashed out of the observatory and pulled the door shut behind him.
       Bud jumped nimbly to the door and wrenched at the knob. "Locked!" he fumed.
       Tom ran over to the intercom to sound the alarm. After jiggling the hook a few times and getting no reply, he gave up.
       "It's out of commission, Bud. Svornin must have sabotaged the mechanism. We'll have to break the door down before the Brungarians get away!"
       Both tom and Bud threw their weight against the metal barrier until it came loose from the hinges. The boys ran to the hangar. The brungarian rocket ship was just leaving, its silvery nose pointing toward outer space.
       "Too late!" Tom groaned.
       "It's my fault, Tom! If I had been alert that guy wouldn't have got a judo grip on me! Maybe the Brungarians won't be able to decipher the ghost log or analyze the rocks."
       "Anyway," said Tom, "we know they're interested in the P-E. Probably they spotted the ghosts through a high-powered telescope or picked up their radio emissions. Svornin and his gang were sent here to find out what we know about the ghosts."
       "And to steal anything they could," Bud added.
       He and the Swifts returned to earth the next day. After landing at Fearing Island, they flew to Enterprises and drove to the Swift home to dinner.
       They were greeted at the door by Tom's mother, an attractive, dainty woman who took a deep interest in the inventions dreamed up by the men of the family. She confessed, however, that she did not understand much of the scientific principles involved.
       Two attractive girls came out of the living room and into the hall.
       "Hi, Sandy!" Bud called to Tom's seventeen-year-old sister, Sandra, who was his usual date. Blond, blue-eyed Sandy was the outdoor type. Her father and brother had taught her to fly jets like a veteran.
       "Hi, Phyl!" Tom called to Phyllis Newton, the daughter of Ned Newton, financial manager of the Swift Construction Company. Dark-haired Phyl accompanied Tom whenever the couples went out as a foursome. She and Sandy were close friends.
       A surprise guest came forward to shake hands. He was James Wooster, an official from Washington and an old friend of Mr. Swift.
       "I phoned this morning," he explained. "Mrs. Swift said you'd be returning from the space station in time for dinner and invited me to join you. I'm here on business as well as pleasure," he added.
       After a delicious meal the men went into the living room for a conference.
       "This is a top-secret mission," Wooster announced. "We want you Swifts and Bud to take a special assignment in Chile, one involving danger as well as diplomacy."
       "I'm not sure I can go," Mr. Swift sad. "But I think you've told us enough to interest Tom and Bud."
       "What kind of assignment is it, Mr. Wooster?" Tom asked.
       "Well, this concerns a mastodon."
       Bud grinned. "You mean one of those outsize elephants that lived in prehistoric times?"
       "That's right," the Washington official said. "It so happens that in the Americas the mastodons survived until the arrival of the Indians, who became great mastodon hunters.
       "Not long ago a perfectly preserved mastodon was discovered in Chile. I don't have to tell you this is a unique specimen and nearly priceless as a relic of the Ice Age. We want it in the United States so scientists can study it for clues to ancient times. The Chilean government has agreed to sell it."
       "We must have offered a fortune," Mr. Swift mused.
       "Yes, indeed," Wooster replied. "And the money is earmarked to raise the standard of living of poor people in Chile. Both nations will gain from this particular transaction."
       Tom was becoming more and more excited. "What do you want us to do, Mr. Wooster?"
       "Your job will be to find the mastodon and transport it to a university on the West Coast, where it will be placed in a museum."
       "That seems reasonably easy," Bud remarked.
       "It would be," said Mr. Wooster, "except for two complications. First, the mastodon is frozen into a pit of ice inside a cave, high in the snow-covered andes. Breaking or melting the ice with vibrating machinery might start an avalanche hurtling down on a village at the foot of the mountain. We hope you can come up with a plan to prevent such a tragedy."
       "That is a problem," tom admitted. "It sounds tough enough by itself. But what's the second complication?"
       Wooster frowned. "An Indian who lives in the village discovered the relic. His neighbors are hostile to the whole idea of removing the mastodon. They don't want anyone else to know where the cave is. They've even refused to guide Chilean engineers to the site for an inspection. Quite an ugly situation has developed."
       Wooster went on to say that the Indians had seen eerie blue flames playing around the high peak. They interpreted this weird phenomenon as a warning from the mountain spirits to leave the frozen relic of the Ice Age where it is.
       "Besides, some Indians claim to have seen a fearsome white giant roaming near the cave."
       "Another Abominable Snowman!" Tom exclaimed with mounting excitement. "Like the reputed Himalayan yeti in Tibet."
       "If you can solve that mystery, Tom, you may find you've unearthed a lead to the location of the mastodon," Wooster said.
       "You mean," Tom replied, "that if I can convince the Indians there are no angry mountain spirits guarding the cave, they'll show us where the mastodon is, and let us remove it?"
       "Precisely."
       "What do you think, Tom?" Mr. Swift queried. "I'd like to take this job, Dad, but my work on the Transmittaton won't wait."
       His father offered to carry on the Transmittaton experiments, and Tom agreed to try to remove the mastodon.
       Tom remarked, "Carting a mastodon from Chile won't be easy. But suppose we can atomize the beast and let it ride an electronic beam to the university for reassembly!"
       "That calls for a king-size receiving tank," Mr. Swift commented. "I'd better solve that problem before you two fellows produce a mastodon with no place to go!"
       Bud chuckled. "It might be interesting if Tom reassembled the beast from the Ice Age in the university dean's office. How about it?"
       "The dean can rest easy." Tom laughed. "Even the animal's two fourteen-foot tusks wouldn't get in that room, to say nothing of its big body."
       Mr. Swift smiled, then became serious. I'll make arrangements with the university tomorrow. A team of Swift scientists will start for the West Coast to begin work setting up the project."
       "Suppose the Transmittaton doesn't work," Wooster asked.
       Tom grinned broadly and replied. "With Dad on the experiments, it's bound to. Besides, we have some earlier inventions to fall back on. If it's a question of cutting an ice block with the mastodon inside, the X-raser will do the trick. As for transportation, I'll order the Sky Queen to stand by."
       This huge craft was the remarkable Flying Lab Tom had devised to carry out experiments in the ionosphere. A triple-decker plane powered by atomic nuclear reactor engines, it was equipped with radar, power units, experimental labs, and large storage holds.
       "That sounds fine to me," Wooster said. "Good luck!" He obviously felt encouraged about the success of the project. He put on his coat and left the Swift home.
       "How about it, Bud?" Tom joked. "Ready for a trip back to the Ice Age?"
       "Wouldn't miss it for all the mastodons in Chile!" his friend retorted.
       The telephone rang in the hall. "For you, Tom," Sandy called. "Harlan Ames says it's important."
       Harlan Ames was the head of the Security Department at Swift Enterprises.
       "What's up, Harlan?" Tom asked.
       Ames's voice sounded as if he were under a strain. "We've just received another report from the space station."
       "What is it?"
       "Ghosts now on Jupiter!"