In a moment the seething radioactive mass would envelop the tiny spacecraft and its two occupants! Desperately Bud jerked at the controls. Tom beamed another message at the oncoming horde!
       "Stop! Stop!" he warned through the Racodio.
       Then, as if some sort of switch had been flipped, the cloud of pulsating globules vanished.
       "They're gone!" Tom shouted.
       "and the repelatron power is back in the life cap!" Bud exclaimed. "Boy, that was weird!"
       There was no time to speculate over the phenomenon. The boys zoomed over to the Cosmotron Express, entered, and stripped off their damaged suits. The inner lining was still intact.
       "Lucky for us the rays didn't get all the way through," Tom said grimly. He ordered the two suits and the life cap sealed in a radiation-proof locker.
       The boys went to the pilot's cabin from which Chow had been watching the encounter. His teeth chattering, he remarked, "Them's a lot o' ornery critters you fellers jest chased off our range!"
       Tom frowned. "We don't know where they've gone, or how long they'll stay away, Chow."
       Bud was hopeful. "The Racodio must have got through to them finally."
       Tom agreed. "But they didn't answer. I want to go out there again and try for another contact."
       Later the boys climbed aboard another life cap for a reconnoitering expedition through the solar system as far as Saturn. But the galaxy ghosts remained out of sight and silent.
       "This is the most puzzling mystery we've ever had," Bud grumbled when they were back in the Cosmotron Express. "I wish that cloud or mist or radiation belt––or whatever it is––had tried to thumb a ride with us! Then we could have found out more about the ghosts."
       "You jest watch," Chow predicted as they prepared for the flight home. "We'll no sooner land an' them mean little critters'll be ridin' the space range again, lookin' for trouble."
       "Chow, you might try to lasso one," Tom said, smiling. "If you can't, I'll give it a try."
       "With what?" Bud asked as he set the control system for Fearing Island.
       "The Transmittaton. Maybe I can trap one of those ghosts in the receiving tank. We'll double the thickness of the Tomasite wall as an extra precaution against that intense radiation."
       "You mean the critter won't be able to get at us?" Chow asked. He looked relieved.
       "Or get away either," Bud remarked.
       "I hope not," said Tom. "but we can't be certain. It'll be risky." For a moment he stared off into space. "Perhaps we can get the ghost to communicate after giving it a taste of captivity."
       The return flight on the Cosmotron Express was uneventful. The three boarded a jet for another flight to Chile, where they landed that afternoon in the valley.
       "Tom, do you know what day this is?" Bud inquired as they clambered from the plane.
       "Yes," the young inventor replied. "This is the fifth day since the Brungarian conversation we heard in the mountains. They may be preparing to make their move!"
       Mr. Swift was waiting in one of Señor Castilla's jeeps. When the boys told him of their amazing encounter with the galaxy ghosts, he commented:
       "You're right, Tom. The Transmittaton is our best bet in dealing with them. Fortunately, I corrected the faulty gadget. You two can go ahead searching for the mastodon cave."
       At the Castilla hacienda Tom and Bud put on their mountaineering clothes, and set out on horseback to explore the area of the blue fire that had nearly engulfed them. When they reached the foot of the mountain, they tethered the animals and began to climb.
       "If we can find the Brungarians' hideout, we'll add an ingredient of our own to their plans!" Tom said. "I hope their machine hasn't arrived yet."
       "It may not be operational," Bud commented. "We might fix their wagon before it starts rolling."
       The boys followed the same path they had taken previously, and continued hunting for clues. They pushed through deep snowdrifts, edged along steep cliffs, and clambered over high peaks.
       Sunset produced a fantastic display of light and shadow on the snow. The icy expanse seemed to be thronged with menacing figures.
       "This is not my choice of a place to get lost in," Bud remarked. "We'd never be found even if the searchers came after us with bloodhounds!"
       At that moment a sound broke the silence. It drew nearer.
       "That's a helicopter," Tom said. "Where is it, Bud?"
       "Coming over that peak."
       The copter hovered, its rotors churning furiously. A door opened and a couple of men lowered a cable with a large oblong box dangling at the end of it.
       "Tom, that must be the Brungarian machine!" Bud whispered. "Why are they dropping it here?"
       Tom pointed. "There's your answer."
       A huge furry white figure was silhouetted against the sky. The creature trampled across the snow with long clumping strides, making for the point where the men in the helicopter were paying out their cable.
       As the descending crate came within reach, the snowman grabbed it and swung the box onto a patch of open ground. After freeing it, he gave a signal.
       The cable was quickly whipped up through the air into the copter. The craft started to move, circled around as if to make sure that everything on the ground was going according to plan, and whirred away among the peaks.
       The hairy figure seized a couple of leather thongs and began to drag the box through the snow. tom and Bud waited to be sure he would not see them, then followed his huge tracks.
       "The same prints we found at the home of Juan Alvarez," Tom muttered.
       "That means he'll take us where we want to go," Bud said. "Let's not lose him."
       Stealthily the boys tailed their quarry around the peak to a wide crack in the icy wall of the mountain. The crevice was hidden by a snow-covered spur of rock. The giant footprints stopped.
       "A natural hideout," Tom observed. "We could have looked for this entrance a hundred years without finding it."
       "Shall we go in?" Bud asked.
       "No use waiting for an invitation, Bud! I want a look at that Brungarian machine. But caution does it. These guys won't be very hospitable if they corner us in there!"
       Tom and Bud scrambled through the crevice into a passage cut in the solid rock by some geological convulsion eons ago.
       "There's a flickering glow at the other end of this passage," Bud whispered.
       Silently the boys stole along the rocky floor. At the opposite end they craned their necks and peered through the opening.
       They saw a large hollow chamber with a fire burning in the center of the floor. A small, thin, sallow man was seated beside it, bound hand and foot. His face was haggard. Brilliant dark eyes reflected his state of terror. The man started with alarm as Tom and Bud emerged from the darkness of the passage.
       "Who are you?" he asked fearfully in Spanish.
       "We are friends," Bud replied. "You are Juan Alvarez, the kidnapped villager?"
       "Sí, señor," the captive replied. "I hope you will help me escape."
       As the boys untied Alvarez they assured him of their aid. He stood up, rubbing his wrists where the rope had bitten into them. Alvarez recounted the story of his capture.
       "It was night, señors. I heard a knock on my door. A very tall man came in. He pointed a revolver and forced me to tell him the location of the cave where the mastodon is. After that, he waved the gun and ordered me to leave my house."
       "The Tall One," Tom murmured. "The guy on Santa Lucia Hill who asked me for a match. But go on, Señor Alvarez. What happened next?"
       The man's eyes widened in a spasm of fear. "A giant appeared! The Snowman of the andes! He seized me! I fainted. when I regained consciousness I was here."
       "Are you hungry?" Tom asked.
       When Alvarez nodded weakly, bud brought out some crackers and a Thermos of hot chocolate he had in his rucksack. Alvarez speedily consumed both, but declined any of Tom's food when it was offered.
       "One thing I've noticed in here," Bud remarked. "When we talk in normal tones, we sound as if we're whispering. Why is that, Tom?"
       "Acoustics. We're dealing with a whispering-gallery effect. Sounds become diminished in this cave, but they carry a long way outside."
       "You are correct, señor," Alvarez put in. "That rock chimney in the corner leads the sounds into the open air. The men from Brungaria have used that means of communication many times since I have been here."
       "What about the snowman?" Tom asked him.
       "I do not know where he is," Alvarez confessed. "I believe he too is a prisoner of the Brungarians. But come with me. There is no time to lose."
       The Chilean led Tom and Bud through a very narrow tunnel that wound and twisted in a direction slanting upward.
       "Seems as if we're climbing toward the top of the mountain," Tom said.
       "Indeed we are, señor, as you will find out when we reach the end of the tunnel."
       Alvarez took them into a large, stony, snowy chamber with a smaller open roof. Looking up, they could see stars in the night sky.
       "That opening is well hidden by encircling boulders," the Indian remarked. "The huge rocks keep this place from being seen by anybody roaming around the mountain.
       "And now for the surprise. I could tell this floor was only a natural bridge," Alvarez went on, "so I took away some of the stones to find out what was underneath." He pointed to the small open section to one side.
       First Tom, then Bud beamed their flashlights into it. Each drew in his breath sharply. Before them lay a deep pit filled with ice. In it was the immense frozen body of a mastodon!
       "What a sight!" Tom said in awe.
       "The way it's lying there, I'd say it's been asleep a lot longer than Rip Van Winkle!" Bud said jokingly. "It's going to be a real job hauling this jumbo out. How did the creature get in here, anyway?"
       "I'm sure it wasn't trapped in a bog and froze into the subsoil, as often happened to prehistoric animals," Tom observed. "This beast must have been chased up here. It fell in, and couldn't get out. Then it froze to death and became embedded in solid ice."
       "Where did the ice come from?"
       "Seepage from an underground spring is my guess. The water rose and covered the animal, froze around it, and here it's been, perfectly preserved, ever since."
       Tom bent down to examine the natural bridge. "A rockfall could have caused this to form," he added.
       "I think you're right, señor," the Indian said.
       Tom, his eyes now adjusted to the darkness, noticed a large object standing in one corner of the cave under a protective canvas.
       "Shine your light over here, Bud," he said, pulling off the canvas. "This is a type of generator. And there are some Brungarian words on it. Translated, they mean Melt Master."
       "Tom, you don't have to tell me what the Brungarians are going to do with it," Bud declared. "They're going to melt the ice around the mastodon!"
       Alvarez shuddered. "That would melt the snow up above and start an avalanche rolling down on my village!"
       "Bud asked, "But how can they remove this bridge?"
       Tom shrugged. "Who knows? It'll be tricky to do that and not ruin the mastodon!"
       He went on grimly, "Bud, you and Señor Alvarez pick up the horses and make tracks for the hacienda as quickly as you can. Alert our crew to prepare to move the mastodon. I'll come along later."
       "What do you intend to do here, Tom?"
       "Put the Melt Master out of commission as much as I can."
       The other two hurried along the tunnel to the big cave. Tom, meanwhile, surveyed the Brungarian machine with a critical eye. "This appears to be a vital connection," he judged, looking at a coil of wires joined to an instrument pane. "I'll wreck that first."
       Grasping the coil firmly in one hand, he gave a hard yank that tore the mechanism loose. It fell to the floor of the cave.
       A terrific jolt knocked Tom off his feet. Everything went black!