"This setup will detect any incoming enemy shock waves," Tom said. "We'll need fifty of 'em, so turn the job over to Swift Construction. And have Uncle Ned put on extra shifts."

The Swift Construction Company, managed by Ned Newton, was the commercial division which mass-produced Tom Jr.'s and Tom Sr.'s inventions.

Information from the detector-transmitters, Tom went on, would be fed into an electronic computer at the Bureau of Mines in Washington.

The Quakelizor itself was housed in a massive cube-shaped casting with two large spheres mounted on top. From each of its four sides jutted a hydraulic piston.

"How does it work, Tom?" Hank asked.

"Dual-control spheres on top," Tom explained, "will receive by radio signal the pulse frequency computed in Washington."

He added that inside each sphere was a "pulsemaker." This would produce changes in the pressure of the hydraulic fluid by affecting the kinetic energy of the fluid's atoms.

The pressure changes would then be enormously magnified in the four hydraulic output drivers. When the unit was embedded in rock, underground, the huge pistons would send out counter shock waves through the earth's crust to neutralize the enemy waves.

"Wow!" Hank Sterling was breathless at the sheer scope of the young scientist's newest invention. "I'll get hot on the job right away."

After forty-eight hours of round-the-clock work, the equipment was ready. Tom conferred by telephone with both Dr. Miles in the Bureau of Mines and Bernt Ahlgren in the Pentagon. He had already chosen the spots for the detector-transmitter check points.

Tom told the men that he believed the best spot for the Quakelizor itself was on a certain government reservation in Colorado. A deep underground cave there would provide a perfect site.

"We'll be close enough to the San Andreas fault to prevent a really huge-scale disaster," Tom explained. "And the Rocky Mountain structure will give us a good bedrock medium for shooting out waves anywhere across the continent."

Dr. Miles and Ahlgren agreed enthusiastically. Tom and the two scientists spoke over a three-way telephone hookup—with automatic scramblers to counter the danger of enemy monitors—laying plans to install the equipment. Ahlgren agreed to fly a technical crew out to the spot in Colorado which Tom had named.

The next day, Tom, Hank, and several top Enterprises' engineers, including Art Wiltessa, took off in the Sky Queen. This was Tom's huge atomic-powered Flying Lab. The massive plane flew at supersonic speeds and was equipped with jet lifters for vertical take-off or hovering.

A Whirling Duck heliplane, loaded with communications equipment, accompanied the Sky Queen. In little more than an hour, the two craft touched down in a rugged Colorado canyon. The government technical crew was already on hand.

"Glad to know you," Tom said, shaking hands with the engineer in charge. He introduced his own men and added, "Better roll up your sleeves. This job is going to take plenty of oomph!"

The parts of the Quakelizor were unloaded from the Sky Queen onto dollies. Then the group, armed with bull's-eye lanterns, flashlights, and walkie-talkies, hauled the parts by tractor into the cave.

"Okay. Now let's pick out the spot for embedding the unit," Tom said.

The men had no sooner begun to look around the huge underground chamber when a fearsome growl rumbled through the cave. Everyone whirled about and the next instant froze in horror.

A huge bear reared up in the mouth of the cave! The monster snarled and blinked its yellow eyes in the glare of lights.

"We're trapped!" Hank cried out.

The enormous bruin was now waving his huge head from side to side, as if daring the intruders to step up and fight.

Several of the government men had brought rifles and shotguns. But in spite of their peril, no one wanted to shoot the handsome old fellow.

"I'll send out an SOS," Tom said. "If help arrives before the bear attacks, we won't use guns."

He radioed the local Forest Ranger post. After a nerve-racking wait, with the group expecting a charge from the beast at any minute, two rangers appeared and captured the bear with a net. One man of the government work crew knocked together a stout wooden cage. The beast, outraged, was loaded aboard the heliplane to be released in an area remote from the cave.



Now the grueling job of installing the Quakelizor began. First the cave was cleared of debris, bats, and other small living creatures. Then a site was marked out on the cave floor. Tom had brought along a midget model of his great atomic earth blaster, which he had invented to drill for iron at the South Pole.

With the blaster, Tom quickly drilled a pit of exact size into the bedrock. Then the Quakelizor was assembled and lowered into place by a portable crane. A power plant and radio antenna were set up and the installation was finally completed.

"I must return to Shopton now," Tom said. "Art here will stick around and help you operate the setup," he told the government engineers after radio contact had been made with Washington. "If anything goes wrong, just flash word to Enterprises."

The Sky Queen and the heliplane sped back across the continent. As Tom landed at Enterprises he was greeted by Bud, who came speeding out on the airfield by jeep.

"Just got back from the space wheel about an hour ago," Bud said. "Your dad's really worried about those exploding radio sets, Tom. He has no clues, but he's sure the scientists working for the Brungarian rebel setup are responsible. He thinks they may try to ruin all of Enterprises' communications system by remote control."

Tom's face was grave as he listened. The two boys discussed the problem as they drove to the Swifts' office in the main building.

"Boy, I sure wish I could think of some way to cope with it," Tom said wearily, flopping down in his desk chair.

"Your dad said to give it the old college try," Bud reported. "And he also said he'd be back in two days to help you on the problem."

Tom glanced at the calendar. "Which reminds me," he said, "on Monday the brain energy will be due from space!"

The thought sent a thrill of excitement tinged with worry through the young inventor's mind. Would the container he had devised prove suitable?

"Hey! A call on the videophone!" Bud pointed to the red light flashing on the control board. He jumped up and switched on the set.

Blake, the Washington announcer, appeared on the screen.

"Bad news, skipper," he said ominously. "An earthquake tremor was just felt here in Washington. It centered in a shipyard on the Potomac and caused great damage!"



CHAPTER X

ENERGY FROM PLANET X

Tom and Bud listened in dismay as Blake reported all the details he had been able to gather.

"Was my Quakelizor a flop, Bud?" Tom muttered, his shoulders drooping as the announcer signed off. "It must have been!"

"Don't be silly! Snap out of it!" Bud gave his pal a cheerful poke in the ribs, hoping to buck him up. "You heard what Blake said—Washington itself was hardly touched. Without your setup, think of all the people that might have been killed or injured! And all the government buildings that might have been wrecked, maybe even the White House. I'd say your shock-wave deflector must have been at least ninety per cent effective!"

Tom brightened somewhat on hearing Bud's words. He picked up the phone, and placed a call to Dr. Miles at the Bureau of Mines. It was almost half an hour before the operator was able to get a line through. But Tom felt the suspense had been worth while when Dr. Miles exclaimed:

"Tom, it was a miracle you completed the Quakelizor installation in time! In all probability it saved us from a major national disaster, perhaps worse than Pearl Harbor!"

Tom felt a glow of pride and relief. "Thanks, sir. But what about the shipyard destruction?" he added, still not entirely convinced.

"That was a bad break, Tom," Dr. Miles admitted. "Our detectors showed that the shock waves had been almost damped out when a sudden power failure occurred. It turned out that an overload had shorted the Quakelizor's power plant. The crew had it fixed within moments, but by that time the damage was done."

Tom winced as he heard of the unfortunate accident, but was thankful the results had been no worse.

Miles went on to say that he had just been conferring with Ahlgren at the Pentagon. The Defense Department now feared that attempts might be made against other large cities and was therefore eager to have Tom deliver several quake deflectors as soon as possible. These would be installed at strategic points around the country.

"The government heads were so impressed with your invention, Tom," Dr. Miles added, "that they'll probably be walking the floor anxiously until the others arrive."

Tom chuckled, then became serious. "Tell them we'll go to work right away," he informed the seismologist. "I'll have the new Quakelizors ready as soon as possible, but you'd better warn your associates it's bound to take a few days."

As soon as the conversation was completed, Tom dialed Ned Newton at the Swift Construction Company. Although he was actually not a relative of the Swifts, both Tom and Sandy had from childhood called him "Uncle Ned."

"What's up, Tom?" he asked.

Tom told him of the latest request from Washington and asked that another three-shift work schedule be set up to turn out the additional Quakelizors.

"Hank and I will bring the blueprints over right away, if you don't mind being late to dinner," Tom said.

Ned Newton agreed willingly, only too happy to help cope with the quake menace. By eight o'clock that evening, work on the project was proceeding at great speed. The Swift Construction Company continued humming with activity around the clock.

The week end was almost over by the time Mr. Swift arrived back from the space station. Tom flew to Fearing Island to meet him. On the short hop back to Enterprises, they discussed the radio problem.

"I think the solution's been staring us in the face, Dad, but we've been too worried to think of it," Tom said. "Remember Li Ching's jamming-wave generator?"

He was referring to a device used recently by an Oriental foe of Tom and his father. Mr. Swift's eyes lighted up with a quick flash of understanding.

"Dad, you wrote a report on the generator for the government with a memo on possible ways to combat it," Tom went on. "Maybe the same measures would work in this case."

The Swifts had discovered that their enemy had been intercepting Tom's messages, thereby learning the frequency to which the Swifts' receiver was tuned. They then radiated a signal at this frequency, modulated at the frequency to which the local oscillator was set. This had caused a buildup of energy in the I.F. transformers, resulting in their explosion.

Now Mr. Swift said, "You're right, son. We'll insert a blocking filter in the R.F. stage that should do the trick."

Their minds relieved of this problem, the Swifts were eagerly looking forward to the arrival of the brain energy from space the next day. The scheduled time, if pinpointed at exactly two weeks from the moment when the first message was received, would be half an hour past noon.

The spot, two miles from Enterprises, was on a lonely hillside. It was shaded by trees, higher up the slope, with bushes and other wild-growing greenery softening its contours. Over the week end, Tom had had carpenters from Enterprises put up a small cabin at the foot.

As twelve-thirty approached, Tom, Bud, Mr. Swift, Hank Sterling, Arv Hanson, and several other Swift technicians stood by at the scene with the star-headed container. Chow had also begged to be on hand.

"I jest got to see Ole Think Box come to life!" he said.

Eyes darted back and forth from wrist watches to sky as the zero moment ticked closer. Bud even began muttering a countdown.

"X minus three... X minus two... X minus one... This is it!"

All eyes flashed skyward. But nothing happened! Not a speck showed in the blue, cloudless sky.

The watchers glanced at one another uncertainly. More minutes went by. Soon it was quarter to one... then one o'clock.

"No mistake about the time, was there?" Arv asked.

Mr. Swift shook his head. "Not if the code was translated correctly." He frowned. "It's true they spoke merely in terms of days. But their time references are usually very precise."

The waiting group fidgeted and prowled back and forth to ease their tension. Feelings of suspense began changing into gloom after two more hours had passed with no sign from the sky.

Disappointed but unable to wait any longer, the technical men went back to the plant, one by one. Hank Sterling, too, and Arv Hanson finally had to leave.

"Sorry, skipper," Hank muttered. "Ring us right away if it shows up."

"Sure, Hank."

As six o'clock went by, Chow tried to pep up his companions' drooping spirits with a simple but tasty supper, warmed up on an electric hot plate in the cabin.

"What do you think, skipper? Are we out of luck?" Bud asked as they ate.

"Our space friends haven't let us down yet," Tom replied. "I'm sure they won't this time." Though he didn't say so aloud, Tom was worried that their Brungarian enemies might have managed to divert and capture the energy.

Mr. Swift seemed to read Tom's thoughts. "Let's hope no hitch has occurred," he said quietly.

The sun went down. Twilight slowly deepened. The trees on the hillside faded from view in the gathering darkness.

"There it is!" Bud yelled suddenly.

Electrified, the four sprang up in an instant. A speck of light was sailing across the sky! But their faces fell as it drew closer.

"Only an airplane," Bud grumbled.

At ten o'clock Mr. Swift gave a weary yawn. "The spirit is willing but the flesh is weak," he confessed. "I got only two hours of sleep on the space wheel, and apparently last night wasn't enough to catch up. Sorry, fellows."

"Why don't you go home, Dad? Hit the hay," Tom said sympathetically.

Promising to take a turn on watch if the vigil continued through the next day, Mr. Swift drove off in his car.

Time dragged by slowly as the three remaining watchers chatted and looked hopefully at the stars. Eventually Chow propped himself against a tree and dropped off to sleep to the accompaniment of low-droning snores. Bud too began to drowse.

It was long past midnight when Tom suddenly caught sight of a moving light in the sky. He stiffened and held his breath. Another false alarm?

But no! A glowing, faintly bluish mass with a comet tail of luminous orange red was slowly proceeding through the pattern of stars!

"Hey, fellows! Wake up!" Tom shouted. He sprang to his feet and unlatched a single point of the star head. Within seconds, Bud and Chow were both wide awake, as excited as Tom. The blue nebulous mass moved closer and closer. The three watchers were speechless with awe.

As the ball of energy descended toward them, it lit up the whole scene. The hillside looked almost as if it were on fire. The earth vibrated, and the air had the sharp smell of ozone. This was followed by a frightening clatter and rumble. The force of the energy was sweeping down rocks, gravel, and shrubbery in a hillside avalanche!

"Look out!" Chow shrieked. "We'll be pulverized in this rock stampede!" He streaked for cover as a huge boulder came plunging straight toward him.

"Hold fast, Bud!" Tom cried. "Nothing's headed our way!"

Steeling his nerves, he grabbed the waiting container and held on grimly. An instant later the glowing mass sharpened and narrowed itself into a snakelike bolt of fire that arced straight into the head of Tom's invention.

Tom gave a yell of triumph and clamped the star point shut, then pushed a button to activate the self-sealing process.

Chow peered out cautiously from behind a clump of rock. The next second, he let out a Texas whoop, bounded from cover like an over-sized gnome, and sent his ten-gallon hat sailing high into the air.

"Yippee!"

Bud cheered too. "The visitor from Planet X has arrived!"

In their excitement and relief, the three hugged one another and jumped for joy.

"Should we wake up your dad and tell him the good news—or keep it a surprise till morning?" Bud asked Tom.

"I guess we'd better—"

Tom broke off in a gasp as the robotlike container suddenly began to whirl—slowly at first, then faster and faster. Spinning crazily like a huge runaway top, it darted up, down, and about the hillside.

Tom and his two companions stared in helpless amazement.

"Great horned toads! What's it up to?" Chow exclaimed.

"Seems like the energy's trying to get out!" Bud guessed. "Something must be bothering it."

Tom shook his head incredulously. "No reason for that. The container was absolutely empty."

Chow suddenly gave a groan and slapped his forehead in dismay. "Brand my Big Dipper!" the cook said. "Mebbe Ole Think Box has gone loco! An' it could be my fault!"



CHAPTER XI

AN ELECTRICAL CHRISTENING

"What are you talking about, Chow?" Tom asked, turning to the old Westerner in amazement.

Chow related how he had dropped the bubble gum inside the robot's head. "Did I ruin the critter?" he asked fearfully.

Tom was thoughtful for a moment, frowning as they watched Ole Think Box continue its gyrations. The figure seemed to be calming down somewhat, although Tom could not be sure of this.

Suddenly his face brightened. A new thought had just struck the young inventor! To Chow's amazement, Tom slapped the cook happily on the back.

"I think you've done me a favor, Chow!" he exclaimed.

"I have?" The old Texan stared at his young boss, as if not sure whether or not to believe him. "How come?"

"You saw how Ole Think Box reacted to the gum," Tom explained. "That shows the energy really is like a brain! It's responsive and sensitive to conditions of its environment, especially when coming up against something new and unexpected."

"You mean they don't have bubble gum on Planet X?" Chow asked with a grin.

Tom smiled as Bud said, "This means we should be able to communicate with it."

"And the brain will probably be able to communicate back to us!" Tom went on excitedly. "We may even be able to learn about Planet X!"

As he spoke, Ole Think Box's whirling became slower and slower. Finally it came to rest close to the three humans.

"What do you suppose happened to the gum?" Bud asked. "Did he chew it all up?"

"It's probably unchanged," Tom replied. "Our visitor is used to it now."

Chow was still wide-eyed with awe. He stared at the strange creature as if expecting it to snap at him in revenge for the gum.

"Don't worry, old-timer. Think Box won't bite," Bud teased. "With that gum spree, he's just been initiated into our American tribal customs!" The pilot grinned. "Hey! We haven't given him a proper name."

"You're right." Tom looked at his pal and chuckled. "Got any ideas?"

"Hmm. Let me see." Bud scowled and paced about with his hands clasped behind his back. "Firetop—John Q. Pyro—"

"But it ain't on fire now," Chow pointed out.

"Maybe not, but he sure blazed a trail getting here," Bud argued.

Tom and Chow countered with several ideas of their own, but nothing seemed suitable until Bud suddenly stopped short and snapped his fingers.

"I have it! He's a visitor from Planet X, so let's call him Exman!" Bud spelled it out.

"Perfect!" Tom was delighted and Chow agreed that it seemed "a right good monicker." The Texan insisted seriously that if the creature were going to be named, he should also have a proper christening.

"Why not?" Tom agreed, as both boys broke into laughter. Bud also liked the idea.

Chow had a troublesome afterthought. He shoved back his sombrero, squinted frowningly at the brain container, and scratched his bald head. "For boat christenings and statues and what not, you break bottles on 'em or cut ribbons or pull a sheet off 'em," the cook said. "But how in tarnation do you christen a buckaroo from space?"

"Nothing to it, Chow," Tom assured him. "We'll do the job up nice and fancy with a display of electricity. But first let's get Exman over to the lab."

The three loaded the energy container into the pickup truck which had brought it to the hillside spot. Then Tom drove back to Enterprises and they took Exman into his private laboratory.

Here Tom attached an electrode to each side of the star head. One electrode was safely grounded, the other connected to a Tesla coil. Then, with all lights turned off in the laboratory, Tom threw a switch.

Instantly a dazzling arc of electricity sputtered through the darkness across the creature's head! The eerie display lit up the room with such impressive effect that both Bud and Chow felt their spines tingle.

"I christen you Exman!" Tom intoned.

For several moments he allowed the fiery arc to continue playing about the star head. Then he opened the power switch and turned the room lights back on.

"Wow! Quite a ceremony!" Bud murmured.

"After a send-off like that, I'll be expectin' the critter to do great things here on this lil ole planet Earth!" Chow declared fervently.

"You could be right," Tom said.

Worn out by the long wait for their visitor from Planet X and the excitement following his arrival, Chow finally went off to his own quarters at Enterprises for a well-earned sleep.

"Guess you and I had better get some shut-eye too, pal," Tom told Bud. "And I think I won't tell Dad until morning."



The two boys decided to bunk on cots in the small apartment adjoining Tom's laboratory. Exman, meanwhile, was left locked in the laboratory with a tiny "night light" showing on him.

"Just a little ray of energy to keep him company," Tom explained with a chuckle.

Minutes later, the two boys were sound asleep. For a while, all was silent. Then the apartment's telephone rang, shattering the stillness. Tom struggled out of the depths of sleep, got up, and groped his way over to the wall phone.

"Tom Swift Jr. speaking."

A familiar voice asked, "Did it come?"

"Oh, hi, Dad!" Tom replied, yawning. "Yes, Exman arrived in fine shape. We've put him to bed. Tell you all about it tomorrow morning."

"Okay, Tom."

As Tom hung up, Bud roused and switched on a lamp. He had awakened in time to catch only part of Tom's words. "Your father?" he inquired.

Tom nodded sleepily and was about to go back to bed. But Bud, still fascinated by the space visitor, decided to have a peek at Exman. He got up and opened the door to the laboratory. A yell from him brought Tom rushing to his side.

"Hey! It's gone!"

The spot by the night light where they had left Exman was now deserted! Tom found a wall switch and pressed it. As light from the overhead fluorescent tubes flooded the room, the boys gave laughing cries of relief.

Ole Think Box had merely moved himself to another corner of the room!

"Guess he didn't like that little chum we left on for him," Bud said with a chuckle.

"Let's leave him where he is," Tom agreed.

The two boys went back to the adjoining apartment and were soon asleep again. Several hours later they were rudely awakened by a loud crash of glass and a heavy thud.

"Something's happening to Exman!" Tom cried.

With Bud at his heels, the young inventor dashed into the laboratory.



CHAPTER XII

EXMAN TAKES ORDERS

A strange sight greeted Tom's and Bud's eyes. In the first rays of sunlight, the space robot was moving back and forth about the laboratory in wild zigzag darts and lunges.

As he rolled toward a bench or other object, the brain energy seemed to send out invisible waves that knocked things over! Already the floor was strewn with toppled lab stools, books, and broken test tubes. The heavy thud had apparently been caused by a falling file cabinet.

"Stop him!" Bud yelped.

Exman was heading straight for a plate-glass window! Reaching from floor to ceiling, the glass formed one entire wall of the laboratory.

"Oh, no!" Tom tensed, realizing that it was hopeless to try to stop Exman in time.

But an instant later, the rolling robot stopped of its own accord, as if registering the fact that its energy waves were now striking a fragile surface. The thick pane of glass vibrated in its frame.

"Good grief!" Tom wiped his brow. "Let's corral that thing before he wrecks the whole lab!"

Exman was already rolling off on a new tack. The two boys managed to grab him before more harm was done. The brain energy in its container seemed to calm under their touch.

"What in the name of space science triggered it off?" Bud wondered out loud.

"Time. It must have reacted to the passage of time," Tom conjectured. "I suppose it just decided to explore this place." He added a bit nervously, "The sooner we can communicate with this energy, the better!"

"But how?" Bud asked.

Tom's brow furrowed. "Say, I wonder if Exman might understand a direct order?"

Tom backed a few paces away from the space robot, then said in a loud, clear voice, "Come here!"

Exman remained fixed to its spot.

"Move right!" No response. "Move left!" Still no response.

"Guess you're not getting through, skipper," Bud commented with a grin.

"No," Tom agreed. "I can't predict what kind of energy this brain will respond to. Being only energy, it must respond to other energy and sound is our form of energy. The problem is the same as with radio waves, which are also energy. We must figure out how we can vary the energy, so it can transmit information to Exman."

"What do we try?" Bud asked. "Or is it hopeless?"

"I'll try communicating with it via the electronic brain, which I have adapted to fit this problem."

The boys cleaned up the wreckage caused by Exman in his dawn venturings. Then Tom went by jeep to the computer laboratory, made connections to his electronic brain, and wired it for remote control. Then he returned to the private laboratory. There Bud watched as he hooked up the leads from the computer to a transmitting-receiving decoder with a short-range antenna.

"Speak, O Master!" Bud said, imitating a squeaky robot voice. "Sound off loud and clear!"

Tom grinned and tapped out a command on the keyboard: Move backward.

Exman rolled backward! Bud gave a whoop of delight.

Tom signaled: Move forward. Obediently Exman rolled toward him.

Stop. Exman stopped.

"Hey, how about that?" Bud exclaimed happily. "It really savvies those electronic brain impulses!"

"And minds them—which is equally important," Tom added.

A moment later the brain energy seemed to become impatient. It spurted off in its wheeled container toward a laboratory workbench.

Crash! A rack of test tubes went sailing to the floor with an explosion of tinkling glass.

Stop! Tom signaled frantically. Again Exman obeyed the order.

"It's like a mischievous kid," Bud said.

Almost as if in defiance, Exman scooted off in another direction. Then it stopped abruptly and swiveled around, one of its antenna arms knocking a Bunsen burner to the floor as it did so.

Come here! Tom signaled. As the culprit approached, he added sternly, Stop where you are. And stay there until you receive further orders.

This time Exman stood patiently, awaiting the next signal. Bud got a brush and dustpan, and the boys cleaned up the broken test tubes and replaced the burner on its shelf.

Then Tom began feeding more complicated instructions to Exman through the electronic brain. He guided him through a number of dancelike movements and other drills, and got him to send out a wave of heat which the boys could instantly feel. Tom was even able to make the robot aim its wave energy so as to short-circuit a switch on an electrical control panel.

Tom was both pleased and excited. "Bud," he exclaimed, "the brain reacts as quickly as that of a highly intelligent being! Just imagine—without any sort of decoding equipment, it can pick up and understand the radio signals I beam out to it!"

"What we need now," Tom went on, "is a simple language to get our ideas across to Exman without having to use the electronic brain all the time. That means I must find a way to give Exman senses as we humans have—smell, touch, sight, hearing, taste. Then it could receive the same reactions we do and talk directly to us!"

"Sounds like quite an order," Bud said wryly. "Speaking of which, how about us phoning Chow an order for breakfast?"

He did so, and a short time later Chow wheeled a food cart into the laboratory. As he dished out man-sized helpings of ham and eggs, the cook kept a wary eye on Exman. Tom was putting the robot through a few more lively maneuvers.

"A good meal'd calm down Ole Think Box," Chow observed grumpily. "But what do you feed that there kind o' contraption?"

"Well, not gum, that's for sure!" Bud teased. After tasting his first forkful of food, he gasped, "And none of this ham!"

Jumping up from his lab stool, Bud began whirling, dancing around, and flapping his arms as if he were burning up.

"Help! Help!" he yelled. "Chow's poisoned me—just like he did Exman!"

Chow's leathery old face paled under its desert tan. "Great snakes, Tom!" the Texan gulped. "Have I really pizened him? Maybe we should call Doc Simpson!"

Doc was the medic in charge of the Enterprises infirmary.

Tom was unable to keep a straight face. "Better call someone with a strait jacket—or a butterfly net!" he said, quaking with laughter. "I'm afraid he's just pulling your leg, Chow!"

Chow's jaw clamped shut like a bear trap and he glared at the pirouetting young flier. Bud collapsed on his stool, doubled over with mirth.

"Sorry, old-timer," he gasped. "I just couldn't resist!"

"Okay, Buddy boy," Chow said darkly. "And mebbe I won't be able to resist gettin' even one o' these days!" The cook stumped out of the laboratory in his high-heeled cowboy boots, a picture of outraged dignity.

"Better watch out, pal!" Tom warned with a grin. "Just remember: it's never smart to bite the hand that feeds you!"

"I guess you're right," Bud agreed, wiping away the tears of laughter. "I'll remember, just as long as Chow promises not to serve us any more armadillo soup or rattlesnake salad!"

Chow's fondness for experimenting with weird dishes was a standing joke around Enterprises.

The boys ate their meal hungrily. As they were finishing, Tom glanced at the big clock on the wall. It was now well past eight o'clock.

"Wonder why Dad hasn't come to the lab," he remarked. "I'd better call and find out if he's all right."

Tom picked up the telephone and asked the operator for the direct line to the Swifts' home. His father answered.

"'Morning, Dad!" Tom greeted him. "I thought after your call last night, you'd be over bright and early to see our visitor. He's already—"

"What are you talking about, son?" Mr. Swift broke in. "I didn't phone you last night!"



CHAPTER XIII

DISASTER STRIKES

Tom was thunderstruck. "You didn't phone me? But, Dad, I got the call—I definitely heard your voice!"

"That's impossible," Mr. Swift insisted. "Believe me, son, I slept soundly from the time I turned in until a little while ago."

There was a moment of stunned silence as both Swifts realized that the telephone call had been faked! Then Tom exclaimed:

"Dad, this is serious!"

"Deadly serious, I agree," his father replied. "Are you calling from your lab?"

"Yes!"

"Stay there. I'll be right over," the elder scientist said.

When Mr. Swift arrived, Tom related his conversation with the mysterious caller. His father listened with worried eyes and a puzzled frown.

"It's bad enough that an enemy was able to get the information," Mr. Swift remarked. "But, potentially at least, it's even more dangerous that he was able to imitate my voice so well. If he could fool you, Tom, he could fool anyone!"

"Are you thinking the same thing I am, Dad?"

"That it may have been some insider here at Enterprises?" When Tom nodded, his father gravely agreed. "Yes, son, it does look that way. To imitate my voice convincingly, it would almost certainly have to be someone who's had close contact with us—either at the plant or here in Shopton."

The thought of a traitor at the experimental station was repugnant to the Swifts and to Bud as well. Not only were all employees carefully screened, but there was a close, almost family relationship among those who took part in the exciting scientific ventures at Swift Enterprises.

Tom called Security and asked Harlan Ames to come over to the laboratory at once. The security chief arrived within moments. Quickly Tom filled him in on the details of the puzzling telephone call.

"Think back, skipper," Ames urged. "Was there anything at all you can remember about the voice that might give us a tip-off? I mean, was it deep, or maybe a bit higher-pitched than you expected? Or anything about the way the caller pronounced his words?"

Tom shook his head. "Nothing. That's the trouble. He spoke only a couple of sentences, but so far as I knew, it was my father calling!"

"Hmmm." Ames frowned. "What about background noises?"

Tom thought hard. "None. If I had detected any special sounds during the call, I'm sure they would have stuck in my mind."

Ames tried another tack. He asked how many people had known about the expected arrival of the brain energy from space. This was harder to answer, but as Tom and his father enumerated the persons, it did help to narrow the circle of suspects.

Besides the Swifts, Chow, Phyl, Ames, and George Dilling, there were three groups who had had access to the information. One was the radio operators at the space-communications laboratory. Another consisted of Arv Hanson and Hank Sterling and the workmen who had taken part in building the energy container. The last group, which also included Hank and Arv, were the technicians who had actually gone to the hillside to await the visitor from Planet X.

Tom scowled. "None of those people would pull such a trick, Harlan—any more than the ones like you and Arv and Hank who are above suspicion. Most of them could have easily obtained the news without going through such a rigmarole."

Mr. Swift nodded. "Tom's right. Unless, of course, they had some urgent reason for wanting to find out as soon as possible."

"Which makes me think it may have been an outsider after all," Tom argued. "Remember, the Brungarians may have intercepted the code messages to or from our space friends." After a moment's silence, he added gloomily, "Whoever the caller was, he knew the energy was arriving. And now he knows it's here!"

Bud interjected, "Well, if he was a Brungarian agent and he's hoping to steal the brain energy, one thing's sure. No earthquake will demolish this place as long as the energy is here at Enterprises."

"A comforting thought, Bud," Mr. Swift commented with a wry smile.

Again Tom frowned. "At any rate, Harlan, see if you can get a line on that impostor."

Ames departed to begin a thorough check of all personnel at the plant who might have been implicated. Bud went on an errand, as Tom began showing his father the accomplishments of the space robot.

"We've christened him Exman," Tom said.

By means of the electronic brain, he made the visitor do a number of maneuvers in response to orders.

"Wonderful!" Mr. Swift exclaimed, greatly impressed. "Let's see if he can use his caterpillar treads as well as he does the wheels."

Tom brought a small flight of portable aluminum stairs which he used for reaching up on high shelves or tinkering with outsized machines. Tom was uncertain at first how to code the command, having no symbol for steps or stairs. Finally he moved Exman to the bottom of the steps and signaled simply: Go up!

Exman paused for a moment, then attempted the ascent. His caterpillar tracks clawed their way up the first step. Then, gingerly, he essayed the next. The robot body tilted, but its gyro kept it from toppling over.

"Bravo!" Mr. Swift applauded encouragingly. But the next instant Exman gave up! He slid back to the floor again with a heavy bump. Then he began whirling and darting about madly.

"Good night! Exman's gone berserk!" Tom cried.

Now wafts of smoke could be seen issuing from the robot's wheels. He was banging wildly about the laboratory, leaving a trail of havoc.

Bud, who had returned, opened the door to come in. Instantly Exman lunged toward him, antennas sparking fiercely and wheels smoking. Bud slammed the door hastily.

The Swifts, too, found it wiser to take cover. They crouched behind a lab workbench until the frenzy was over. Presently Exman subsided and rolled to a complete standstill.

"Good grief!" Tom stood up cautiously and eyed the creature. It made no further move. Bud poked his head through the doorway for a wary look, then re-entered the laboratory.

"What made him blow his top?" Bud asked.

Then Tom heard a quiet chuckle from his father. "Actually, boys," the elder scientist said, "I think we should be encouraged."

"Encouraged?" Tom stared at his father.



Mr. Swift nodded. "Yes, the whole thing was rather a noteworthy reaction. I believe Exman was displaying a fear complex about navigating up those stairs."

Tom gasped, then broke out laughing. "Dad, you're right! I'll bet when its body tilted over, the brain wasn't sure whether the gyro would keep it from being wrecked. It just shows Ole Think Box is getting more human all the time!"

Bud ventured to pat Exman on its "back." "Relax, kid," he said with a chuckle. "You're among friends and we wouldn't dream of letting you get hurt. You're too valuable!"

Mr. Swift stroked his jaw thoughtfully. "Valuable, yes, if we can only get it to communicate. Tom, I believe the first project we should work on is a way to make Exman talk."

After the debris had been cleaned up, the two scientists pulled up stools to the workbench and began to discuss the problem. Bud, seeing them absorbed, and realizing the discussion would soon be far beyond his depth, snapped a grinning salute at Exman and quietly left the laboratory.

"Dad, the toughest part won't be the speech mechanism itself," Tom pointed out. "There are several ways we could handle that—by modulating a column of air, for instance, or by some sort of speaker diaphragm. The real stumper will be how to teach him our spoken language."

Mr. Swift nodded. "I'm afraid you're right. If the inhabitants of Planet X communicate telepathically, or by some sort of wave transfer, they may have long since forgotten any concept of a spoken language."

The Swifts batted several ideas back and forth. Then Tom snapped his fingers.

"Wait, Dad! We have the answer! The electronic brain!"

Mr. Swift's eyes lighted up. "Of course! The machine already translates the space code into written English. All we need do is add a device to convert the machine's impulses into sound!"

In two hours the Swifts had put together a mechanism designed to work through a tape recorder. This was hooked up to the electronic brain.

After recording for several moments, Tom reversed the tape and switched on the playback. A squeaky jumble of noises could be heard. But one word seemed to come through fairly distinctly. "Universe!"

"It's talking!" Tom cried out.

"Trying to, but not succeeding very well," Mr. Swift said.

Nevertheless, the two scientists were jubilant at this first breakthrough. Eagerly they began making adjustments—both on the electronic-brain hookup and the converter mechanism. Tom was just about to switch on the tape recorder again when the telephone rang.

The young inventor was annoyed at being interrupted at such a crucial moment, but picked up the phone. "Tom Swift Jr. speaking."

"You have an urgent call from Washington," the operator informed him. "Just a moment, please."

Bernt Ahlgren was calling from the Pentagon. The defense expert's voice was strained.

"Tom, there's just been another attempt to cause an earthquake here in Washington!"

Tom gasped. "What happened?"

"It failed, thanks to you. But Intelligence believes an attempt will be made on New York City very soon. We need your help to stop it. How near completion are the other shock deflectors?"

Before Tom could answer, he heard excited voices at the other end of the line. Then Ahlgren broke in again abruptly.

"A news flash, Tom! The Walling range-finder plant has been demolished by an earthquake!"



CHAPTER XIV

AIR-BORNE HIJACKERS

Mr. Swift, hearing Tom's dismayed reaction, rushed to the telephone.

"What's wrong, son?"

Tom clamped his hand over the mouthpiece and quickly gave his father the news of the destroyed range-finder plant. Then he spoke into the telephone.

"Bernt, we must prevent another disaster! Let me check with our construction company on the Quakelizors and I'll call you right back!"

"Right, Tom," Ahlgren agreed.

Both Tom and Mr. Swift were shocked by this latest blow of their enemies. Tom called Ned Newton at the Swift Construction Company at once and told him the news.

"How soon will the Quakelizors be ready, Uncle Ned?"

"They're finished, Tom. We're running a final inspection on them right now. We can have them ready to ship out by one o'clock."

Tom relayed word to the Pentagon. Bernt Ahlgren was greatly relieved. "By the way," Tom went on, "what about the sites? Have they been chosen yet?"

"Only tentatively," Ahlgren replied. "We wanted to get your opinion first."

One of the deflectors, Ahlgren felt, should be based in position to guard the New York and New England area, in view of Intelligence warnings about a probable attack on New York City. Another, in the Cumberland plateau region of Kentucky, could damp out shock waves threatening either the heavily industrialized Great Lakes area or any southern city.

As to the other three Quakelizors, Ahlgren suggested that one be installed on the West Coast, one in the Black Hills of South Dakota, and the third on the Atlantic island of San Rosario. This would protect both Latin-American allies and Caribbean defense bases of the United States.

Before deciding, Tom asked that Dr. Miles at the Bureau of Mines be circuited into the telephone conversation. Mr. Swift, too, joined in on another line. The four scientists discussed the problem and referred to geologic maps. Finally the exact sites were agreed upon.

"Dad, I'm going to deliver and install one of those Quakelizors myself," Tom declared, after the telephone conference ended. "Judging from that phone impostor last night, there's no telling what sort of trick our enemies may try next!"

Mr. Swift approved heartily. "Good idea, son. In the meantime, I'll see what I can accomplish with Ole Think Box here."

Tom notified Uncle Ned of the delivery sites. He requested that because of the urgency of the situation, Swift planes transport the Quakelizors. Mr. Newton promised to have five cargo jets loaded and prepared for take-off from the construction company airfield.

Next, Tom turned to the job of rounding up flight crews. He decided that Hank Sterling, Arv Hanson, Art Wiltessa, and a crack Swift test pilot, Slim Davis, would each captain a plane.

Tom was just hanging up the telephone when Chow wheeled in a lunch cart, bearing sizzling servings of steak for the two Swifts.

"How's Ole Think Box comin' along?" Chow inquired.

"All right now, but he went berserk a while back," Tom replied with a chuckle.

Chow eyed the robot apprehensively and made a hasty exit. Both Tom Jr. and Tom Sr. were amused.

As they ate, the two scientists continued their discussion on how to equip Exman with senses and the power of speech. Several minutes later, when they were finishing dessert, Bud came into the laboratory.

"Tom, what's this about you hopping off somewhere to install a Quakelizor?" he asked anxiously.

"Don't worry, pal. I'll need my usual copilot," Tom said with a grin. "Just didn't have time to call you before lunch. We'll be flying down to a place called San Rosario in the Caribbean."

At one o'clock Tom briefed the flight crews and technicians. Slim was provided with three men who had worked on the original model of the quake deflector. After making sure that every man knew his job, Tom had the groups flown by helicopter over to the Swift Construction Company airfield.

Tom and Bud's cargo jet was the second to take off. On signal from the tower, the big workhorse thundered down the runway and soared off into the blue. Soon it was spearing southward above the waters of the Atlantic.

Presently Bud drew Tom's attention to some blurry specks of light on the radarscope. "Looks like a formation of planes, skipper."

Tom studied the blips for a while. "Guess you're right. It's sure not a flock of sea gulls!" The young inventor frowned.

"Worried, Tom?" Bud asked quietly.

Tom shrugged. "It could be a routine military flight."

He increased speed and climbed for altitude. But the blips on the radarscope showed that the planes were coming steadily closer. It was clear that they were targeting on the Swift cargo jet.

Tom switched on the radio. Presently a voice crackled over their headphones:

"Calling Swift jet!" The voice was heavily accented.

"Brungarians!" Bud muttered.

Tom made no reply to the radio challenge. Again came the voice:

"Calling Swift jet! Make emergency landing on the water!"

Tom's only response was a fresh burst of speed. Gunning the jet motors, he sent the big cargo ship arrowing forward at supersonic velocity.

"There they are!" Bud cried suddenly. He pointed to a cluster of silvery glints in the sky at seven o'clock.

Tom zoomed downward into a billowing cloud bank. It was a feeble hope and Tom knew it. His only real chance now was to outrun or outmaneuver the marauders.

The slim hope faded as they emerged from the cloud cover moments later. The enemy planes were not only still dogging them, but closing in rapidly. Sleek, needle-nosed attack ships, they appeared to have seaplane hulls.

"Wow! Those are new ones!" Bud gasped.

"Our last warning to Swift jet! Hit the water or be shot down!" came the enemy voice.

Tom raced along, his mind searching frantically for a method of escape.

Bud switched off radio power momentarily. "If we're going to be hijacked, skipper, let's ditch your invention before it's too late!"

Tom shook his head stubbornly. "Why should I let those pirates bulldoze us? Actually, I think they're after Exman!"

This last thought was a hunch that had just occurred to Tom. It was clear that their foe had learned about the arrival of the energy from space. "But so far," Tom reasoned, "there's no cause to suppose they know anything about the quake deflectors."

Stalling for time, Tom switched on the radio again and spoke into the mike. "Swift jet to attack planes. Our home base is picking up every word of your threats. Shoot us down and America will consider it an act of war!... Care to risk it?"

There was a moment's silence, then a reply. "War, you say? How can there be a question of war? War against whom? You do not even know our national identity!"

"Don't kid yourselves, mister!" Bud put in with a snarl. "We know, all right, and so does United States Intelligence!"

Tom decided to risk a blunt query, without actually giving away any facts, in case his hunch about the Brungarian's knowledge was wrong.

"There was a phone call to Swift Enterprises last night," he radioed. "We know it was a fake. We also know your agents are aware of our visitor.... Right?"

After a pause, the enemy spokesman replied, "Perhaps. If so, what then?"

"Just this," Tom radioed back. "If you're hoping to meet our visitor, you're out of luck. I'll give you my word for it. Do you think we'd risk such a valuable character in an unguarded crate like this?"

Tom and Bud looked at each other. Somehow, both boys felt instinctively that Tom's words had struck home. The enemy had certainly risen to the bait.

Finally came the reply. "You Swifts have a reputation for scrupulous honesty." There was a slight sneer in the speaker's voice as if he considered this a foolish weakness. "You give me your word of honor that this—er—character is not aboard?"

"I do!" Tom snapped. "And if you don't trust me, go ahead and risk a war!"

The boys waited breathlessly for the outcome of Tom's bold gamble. Soon they saw the result. The pursuing planes suddenly peeled off and sped away in the direction from which they had first appeared.

"Whew!" Bud wiped his hand across his face and drew it away moist with perspiration. "How do you like that?"

Tom chuckled with relief. "I like it fine, fly boy. But I was sure worried there for a while!"

Less than an hour later, the big cargo jet touched down at the San Rosario airport. An armed guard was on hand to greet the boys, under command of an officer named Captain Sanchez. He had brought along a work crew of soldiers and also a geology expert, Professor Leone, from the island's small technical school.

"I have selected a spot on the eastern shore of the island," the professor told Tom. He unrolled a map and explained the site.

"Excellent," Tom agreed.

The Quakelizor parts, communications equipment, and small atomic earth blaster were quickly unloaded and transported to the site by trucks. In three hours the installation was finished.

Tom, who spoke Spanish fairly well, explained to a small group of San Rosario military technicians how the quake deflector worked. He also detailed one of his own men to stay on as trouble shooter for the setup.

"And now," said Captain Sanchez, beaming, "we must relax and celebrate the friendship of our two countries."

Tom and Bud, though eager to get home, hesitated to hurt the friendly officer's feelings. They sat through a delicious meal, followed by numerous speeches. When his own turn to speak came, Tom used it to warn against possible sabotage attempts by the Brungarians. At last the boys were allowed to take off with their crew.

"Swell guys," Bud said, when the boys were airborne, "but a bit hard to break away from!"

Tom grinned, then became serious. "You know, Bud," he said thoughtfully, "those aerial hijackers gave me an idea."

"Let's have it, skipper."

"If only I could get Exman perfected so he would report back to me," Tom explained, "I could let him be kidnaped. Think what a wonderful 'inside man' he'd make in the enemy setup! He could tip us off to everything the Brungarians were doing!"

"Hey, that's neat!" Bud exclaimed, wide-eyed. "But how could you be sure those Brungarian rebel scientists wouldn't change him somehow? I mean they might brainwash him or something."

"It's a risk," Tom agreed. "But that's my problem—how to make a perfect spy out of him."

It was midnight when the cargo jet touched down on the Enterprises airfield. The boys slept soundly.

The next morning Tom reported to Mr. Swift and Harlan Ames the outcome of his trip to San Rosario, including the attack en route by unmarked sky raiders. He also privately told his father about his plan to use Exman as an electronic spy. Mr. Swift was enthusiastic.

The two scientists promptly set to work. Mr. Swift built two powerful but miniature radio sets; one for receiving, one for transmitting. Tom, meanwhile, was busy on another device, also highly miniaturized, combining features of both the electronic decoder and Tom's famous midget computers, known as Little Idiots.

With this equipment, Tom hoped, Exman would be able to monitor all communications at Brungarian rebel headquarters, then radio the information to Enterprises.

Chow brought lunch to the laboratory at noon, and Bud came in later. Both stayed to watch the outcome of the experiment. Hank Sterling and Arv Hanson joined the group.

By midafternoon the equipment was ready for a tryout. Tom opened Exman's star head, inserted the gear, and made the delicate wiring connections.

"So far, so good," the young inventor murmured, stepping back. "Now for the real test! Will Exman answer our questions?"

Tom walked over to the electronic decoder brain and began to tap out a message on the keyboard. The others waited in breathless suspense.



CHAPTER XV

KIDNAPED!

The message which Tom signaled in code over the electronic brain said:

WE HAVE A DANGEROUS PLAN. IF PLAN WORKS, YOU MAY BE EXPOSED TO ENEMY TAMPERING. WILL THIS BE SAFE? CAN YOU STAND THIS?

There was a tense pause. Then the signal bell rang on the machine and the keys began to punch out a reply on tape:

NO ONE CAN ALTER THIS BRAIN NOR CAN THEY CHANGE ITS PURPOSE. THEY CAN ONLY DESTROY THE ENERGY HOLDER.

As Tom finished reading the message aloud, Chow gave a whoop of delight and the whole group burst into spontaneous cheers.

"Terrific, skipper!" Bud exclaimed, clapping his pal on the back. The others gathered around to add their congratulations.

Mr. Swift, beaming with pride, gave Tom a quick hand-squeeze. "It's an amazing achievement, son. And it may prove to be the key for unlocking the secrets of space, if and when we have time for some research after this crisis is over."

"I sure hope so, Dad," Tom murmured. Though jubilant, the young inventor realized that this was only the first step in his plan to checkmate the Brungarian rebels.

The real perils still lay ahead!

Tom called Harlan Ames and asked him to come to the laboratory for a conference. When the security chief arrived, he was as impressed as the others with the way Tom was able to communicate with Exman.

"The problem now," Tom said, "is how do we have him kidnaped?"

Chow, wary as a coyote, offered his opinion that the safest way would be merely to leave the space robot unguarded somewhere about the grounds of Enterprises.

Ames shook his head. "Too obvious. They'd suspect a trap." Tom agreed.

"Wal, then, how about truckin' him along the highway hereabouts, as if you all were sendin' him down to Washington?"

This, too, was vetoed on the grounds that a shrewd espionage agent would guess that such a valuable prize would never be entrusted to a slow and vulnerable method of transport.

"Then what about an air flight?" Hank Sterling suggested.

"Brand my six-guns, that'd be jest beggin' to git yourself shot down!" Chow fumed.

"Not if we used a plane like the Sky Queen, equipped with jet lifters," Hank argued. "If any hijack planes jumped us, they'd have to let us come down safely in order to get their hands on Exman. We could land on the water or just hover while they made the transfer."

"And after they had it safe aboard their own plane, they'd blast yours to smithereens!" Chow retorted.

Tom, too, thought a plane flight unwise, but for different reasons. It might look suspicious to the Brungarians after the Swifts had been warned by one aerial hijack attempt. Also, they might be deterred by fear of war, thinking that the United States Air Force would doubtless be alerted to the possibility of attack.

"So right," Ames agreed. After a thoughtful pause, he added, "Tom, what about transporting Exman by submarine? We know that every spy apparatus in this hemisphere is constantly trying to probe what goes on at Fearing Island, where our subs are based."

"No doubt about that," Tom conceded.

"So," Ames continued, "any move to Fearing would certainly make the Brungarian agents prick up their ears. Their own spy subs probably would come prowling around the island and detect the departure of a Swift sub. And they might feel that an undersea hijack attempt would be a fairly safe gamble."

The others looked thoughtful, then slowly nodded in agreement. Ames's reasoning sounded highly logical.

"Tom, you'll insist on going, I suppose," Mr. Swift said somberly.

"Of course, Dad. After all, the kidnap plan was my own idea," Tom replied. "Another thing I'll insist on is that you don't go. We have Mother and Sandy to think of, and it's not right that both of us risk our necks."

Realizing that it was hopeless to dissuade his son, and realizing the basic fairness of Tom's position, Mr. Swift did not argue. Bud, Hank, Chow, and Arv immediately volunteered to accompany the young inventor on his dangerous mission.

Tom gratefully accepted their help. He asked all hands to assemble on the Enterprises airfield at six the next morning for the flight to Fearing.

After the others had left, Tom and his father resumed their experiments with Exman. Mr. Swift suggested adding a device to the radio equipment to make it disintegrate if tampered with. "Before those rebel Brungarians can learn the secret of your electronic spy."

"Good idea, Dad. And how about our doing the job with Swiftonium?" This was an unusual radioactive ore which Tom had discovered in South America.

Mr. Swift nodded as he began work.

Tom watched admiringly as his father reconstructed the radio, coating the entire thing with a Swiftonium compound. He at once placed the set in a small oven which he raised to 50 degrees centigrade.

"When this cools, the set will be stable," Mr. Swift said. "But if you should move any part of it after it cools, all of the organic parts, like the circuit boards, the insulation, the carbon resistors, etc., will oxidize and disappear as gas. You will not even be able to tamper with a single unit."

"Wonderful, Dad," Tom murmured when the device was finished. "I wish I had your know-how in microchemistry."

"And I wish I had yours in electronics!" the elder scientist declared with a chuckle.

After Mr. Swift had installed the device in Exman's star head, Tom used the electronic brain to inform the robot about the whole scheme.

Both Tom Jr. and Tom Sr. were delighted when Exman showed real enthusiasm. It replied via the printed tape on the decoder:

DO NOT WORRY, MY FRIENDS. I WILL NOT RESPOND TO ANY ATTEMPTS BY BRUNGARIAN SCIENTISTS TO COMMUNICATE WITH ME. MY PLANET IS WELL AWARE OF THEIR DANGEROUS AIMS. HAVING CONQUERED YOUR WORLD, THEY WOULD NEXT INVADE SPACE.

"Looks as though Exman's got their number, all right!" Tom said with satisfaction.

Early the next morning Mr. Swift drove Tom to the Enterprises airfield to meet his friends. Hank Sterling, Bud, and Chow were already on hand, and Arv Hanson arrived a few moments later. Tom and Bud left the others to bring Exman in a small panel truck.

Soon the space robot was safely loaded aboard a transport helicopter. The others took their places inside the cabin.

"Good luck, son!" Mr. Swift forced a smile as he gave Tom a parting handshake.

"Don't worry, Dad. I'll be back soon!" Tom assured him. The nature of the trip had been described only vaguely to Mrs. Swift and Sandy in order to keep them from worrying.

The short hop overwater to Fearing Island was soon completed. Lying just off the Atlantic coast, Fearing had once been a barren, thumb-shaped expanse of scrubgrass and sand dunes. Now it was the Swifts' top-secret rocket base, tightly guarded by drone planes and radar.

As the helicopter approached its destination, Tom radioed for clearance, then whirred down toward the landing field. The barracks, workshops, and launching area of the base lay spread out in full view. Cargo rockets bristled on their launching pads, along with Tom's spaceships, including the mighty Titan, and the oddly shaped Challenger and Cosmic Sailer.

North and south, the island was fringed with docks. Here the recovery tugs and fuel tankers were moored, as well as the Swifts' fleet of undersea craft.

Tom had chosen a cargo-hauling jetmarine, named the Swiftsure. It was a larger version of his original two-man jet sub, the Ocean Dart. He had given orders the night before to have it ready for sea by morning.

By jeep and truck, Tom's group sped across the island to the dock. Exman was quickly lowered aboard through the sub's hatch. The others followed, the conning-tower hatch was dogged shut, and soon the Swiftsure was gliding off into the shadowy blue-green depths.

"What's your sailing plan, skipper?" Hank Sterling inquired. The quiet-spoken, square-jawed engineer stood beside Tom at the atomic turbine controls and looked out through the transparent nose of the jetmarine.

"Go slow. Give 'em plenty of chance to pick up our trail," Tom replied.

For two hours they cruised at moderate speed. Nothing happened. Disappointed, Tom surfaced and radioed his father for news, after cutting in the automatic scrambling device.

"You're in time for an exciting flash," Mr. Swift reported jubilantly.

"What is it, Dad?"

"An attempt to earthquake New York has just failed!"

Grins broke out on the faces of the crew as they heard Mr. Swift's words come over the loud-speaker. Bud let out a happy whoop.

"That's great, Dad!" Tom said. "Maybe we've got 'em licked on the quake front. No luck so far, though, on our new project."

"Well, keep in touch and let me know at once if anything happens," Mr. Swift urged.

"Right, Dad!" Tom promised.

Again the Swiftsure submerged. This time it was only a few minutes before Arv Hanson gave a cry of warning.

"Something on the sonarscope, skipper!"

Bud, Hank, and Chow hastily gathered around the scope to watch. The blip grew larger rapidly. It was clearly another submarine, closing in on a collision course.

Tom put on a burst of speed, as if attempting to outrace their pursuer. But he was careful to gauge his knots by reports from the sonarscope, in order not to widen the gap between the two craft. There seemed no danger that this would happen, although the Swiftsure raced ahead faster and faster. Still the enemy sub continued to close in like a marauding shark, finally passing Tom's craft.

"Some baby!" Bud muttered respectfully.

The words were hardly out of his mouth when a missile streaked across their bow, in plain view through the Swiftsure's transparent nose. Its foaming wake rocked the jetmarine.

"They're attacking us!" Bud cried out.

Tom slammed shut the turbine throttle, bringing his craft to a gliding halt in the water. At the same time, he switched on the sonarphone.

"Orders to Swift sub!" a voice barked over the set. "Surface and heave to! No tricks, or the next missile will not be across your bow!"

Tom blew his tanks and sent the Swiftsure spearing upward. As the conning tower broke water, Tom and his men swarmed up on deck. Seconds later, a sleek gray enemy submarine knifed into view. Its hatch opened and several men climbed out.

To Tom's amazement, their leader was Samson Narko!

Chow let out a yelp of rage. "Why, you sneakin', double-dyed, bushwhackin' polecat!" the old Westerner bellowed. "We shoulda kept you hawg-tied, 'stead o' lettin' you go free!"

Narko ignored the outburst and raised a megaphone to his lips. "Hand over your cargo and do it quickly!"

"What cargo?" Tom snapped back. "And what's the meaning of this outrage? You realize this is piracy?"

"I realize you will wind up on the bottom at the slightest show of resistance!" Narko warned menacingly. "You know very well what cargo I refer to! Now do not try our patience!"



Tom and his crew pretended to put up a blustering, indignant front. Chow was especially convincing, with a blistering torrent of salty Texas invectives.

Narko's only response was a barked-out order to his men in Brungarian. Quickly the enemy submarine maneuvered closer until the two craft were almost chockablock. Narko and his men then leaped aboard the Swiftsure, armed with sub-machine guns and automatics.

"I'm warning you, Narko—" Tom began angrily. But Narko cut the young inventor short by a poke in his ribs with the gun muzzle, then issued orders to two of his men to go below.

Moments later, Exman was being hauled up through the hatch and transferred aboard the raider. The Americans glared in angry silence.

"Thanks so much, my stupid friends!" Narko taunted them with a jeering laugh. Then he followed his crewmen as the last one scrambled back to the enemy submarine.

With laughs and waves, they disappeared into its conning tower. The hatch was clamped shut and the raider promptly submerged.

Tom and his men were amazed, but delighted at not having been taken prisoner along with Exman. All of them broke into happy chuckles of relief.

"Wow! That's what I call fast service!" Bud exclaimed.

"It was sure a blamed sight easier'n I expected," Chow said. "Thought fer a while we might end up feedin' the fishes!"

"You put on a real act, Chow!" Tom said, clapping the stout old cook on the back. "Well, they've taken the bait. Now let's hope it pays off—for us!"

The Americans swarmed below again, closed the hatch, and submerged. Tom took his time in bringing the jet pumps up to speed. "Wonder if we should pretend to proceed on course, or turn around and head for home?" he murmured to Hank.

Hank's reply was cut short by a yell from Hanson at the sonarphone.

"Missile coming, skipper! Straight at us!"



CHAPTER XVI

A UNIQUE EXPERIMENT

"Bearing?" Tom cried.

"One-seven-five!" Arv Hanson sang out.

Tom gunned his port jet turbine and swung the Swiftsure hard right. The abrupt turn at high speed sent the craft sideslipping crazily like a skidding race boat.

"Here she comes, skipper!" Bud yelled. He had rushed to the sonarscope with the other members of the crew.

Tom's maneuver had carried them a good hundred yards off the missile's course. Now he yanked a lever, pulling the cadmium rods still farther from the atomic pile, in order to increase power and jet-blast their sub still farther out of range.

But suddenly the men at the scope blanched. "The missile's turning too!" Hank cried. "It's homing in on us!"

Unlike most Swift craft used on scientific expeditions, the cargo sub's hull had not been coated with Tomasite. This would have insulated it from all magnetic effects or any form of pulse detection. Tom had chosen the Swiftsure partly for this very reason, so that the Brungarian rebels could easily pick up its trail after leaving Fearing.

How ironic if his choice should prove fatal! As the thought flashed through Tom's brain, the missile came streaking into view through the sub's transparent nose.

By this time, Tom had flipped up the Swiftsure's diving planes. The craft plummeted deeper into the ocean depths.

"Brand my whale blubber, she's turnin' again!" Chow gulped. The missile's arc, as it veered around to follow, painted a streak of light on the sonarscope.

Anxious moments raced by while Tom steered their craft in a deadly game of tag with the sub-killer. Gradually the missile appeared to be losing momentum.

"It's slowing down, all right!" Arv called out.

In a few minutes the missile had lost so much way that Tom was easily able to outdistance it. The crew crowded to the scope, heaving sighs of relief. The missile, its velocity spent, sank harmlessly toward the bottom.

"Boy, what a close call!" Bud gasped weakly. "You played that thing like a toreador sidestepping a bull, Tom! Nice going!"

The others echoed Bud's sentiments, with fervent handshakes and backslaps for Tom's skillful evasive action.

"Jest the same," said Chow, "I'd sure like to make Narko an' them Brungarian hoss thieves dance a Texas jig with a little hot lead sprayed around their boot heels! Sneakin' bushwhackers! It's jest like I told Hank about his airplane scheme—they'd try to gun us down, like as not, soon as they got their hands on Exman!"

"I guess you had them figured right, Chow," Tom agreed wryly. "Well, at least we've lost their sub!"

The Brungarian raider was no longer visible even as a faint blip on their radarscope. Evidently Narko had thought the jetmarine a sure victim and headed back to his own base.

Nevertheless, Tom steered a wary zigzag course back to Fearing. When they arrived at the island, he immediately telephoned Bernt Ahlgren and Wes Norris in Washington to report the hijacking of the space brain. Both men praised the young inventor for his daring scheme to outwit the ruthless Brungarian rebel clique.

"If your idea pays off, Tom, we should be able to checkmate every move those phonies and their allies make!" Norris declared.

"I'm hoping we can do even better than that," Tom replied. "Part of my plan is to help the Brungarian loyalists through Exman's tip-offs. With some smart quarterbacking, we might be able to rally the rightful government before all resistance is crushed out."

"Terrific!" Norris exclaimed. "Let's hope your scheme works!"

Tom had ordered the space oscilloscopes to be manned constantly, both at Fearing and at Enterprises, in case of a flash from Exman. But no word had yet been received when Tom and his companions arrived at the mainland late that afternoon.

Mr. Swift greeted his son warmly at the airfield. Tom had refrained from radioing the news to Enterprises after the hijacking and the missile attempt. Any such message, Tom feared, might be picked up by the enemy and bring on another attack. But the young inventor had telephoned his father immediately after calling Washington.

Now Mr. Swift threw his arm affectionately around the lanky youth. "You look pretty well bushed, son. Why not hustle home and call it a day? That goes for the rest of you, too," he added to Bud, Chow, and the others. "You've just risked your lives and the strain is bound to tell."

Tom urged his companions to comply. "But I'm sticking right here," the young inventor told his father. "I want to be on hand the minute Exman contacts us."

Bud insisted upon staying with his pal. The two boys ate a quiet supper in Tom's private laboratory and finally lay down on cots in the adjoining apartment. But first Tom posted a night operator to watch the electronic brain.

"Wake me up the second that alarm bell goes off," he ordered.

"Okay, skipper," the radioman promised.

No message arrived to disturb the boys' rest. Tom felt a pang of worry as he dressed the next morning, and then relieved the man on duty at the decoder. Had the Brungarians somehow outwitted him? Surely Exman should have reported by this time!

"Relax, pal," Bud urged. "Our space chum's hardly had time to learn any secrets yet. Besides, those Brungarian scientists are probably giving him the once-over with all sorts of electronic doodads. Why risk sending a message till he has something important to tell us?"

"That's true," Tom admitted.

Chow brought in breakfast. "You jest tie into these vittles, boss, an' stop frettin'," the cook said soothingly. "I reckon Ole Think Box won't let us down."

Tom sniffed the appetizing aroma of flapjacks and sausages. "Guess you're right, Chow," he said with a chuckle.

As the boys ate hungrily, Tom's thoughts turned back to the problem of how to equip Exman with senses. He talked the project over with Bud. Most of his ideas were too technical for Bud to follow, but he listened attentively. He knew the young inventor found it helpful to have a "sounding board" for his ideas.

"Too bad I didn't have time to tackle the job before Exman was kidnaped," Tom mused. "Think how much more he could learn with 'eyes' and 'ears'!"

"Stop crabbing," Bud joked. "Isn't an electronic spy with a brain like Einstein's good enough?"

Mr. Swift arrived at the laboratory an hour or so later. He found Tom setting up an experiment with a glass sphere to which were affixed six powerful electromagnets. Two shiny electrodes, with cables attached to their outer ends, had also been molded into the glass. Bud was looking on, wide-eyed.

Tom explained to his father that he had blown the sphere himself, following a formula adapted from the quartz glass used for view panels in his space and undersea craft.

"What's it for, son?" Mr. Swift asked, after studying the setup curiously.

"Don't laugh, Dad, but I'm trying to produce a brain of pure energy. A substitute for Exman, so we can go ahead with our sensing experiments."

Mr. Swift reacted with keen interest and offered to help. "But remember, son," he cautioned, "at best you can only hope to produce an ersatz brain energy—which will be vastly different from the real thing. Don't forget, Tom, the mind of a human being or any thinking inhabitant of our universe is based on a divine soul. No scientist must ever delude himself into thinking he can copy the work of our Creator."

"I know that, Dad," Tom said soberly. "Man's work will always be a crude groping, compared to the miracles of Nature. All I'm hoping to come up with here is a sort of stimulus-response unit that we can use for testing any sensing apparatus we devise."

The two scientists plunged into work. First, a bank of delicate gauges was assembled to record precisely every electrical reaction that took place inside the sphere. Then Tom threw a switch, shooting a powerful bolt of current across the electrodes. The field strength of the electromagnets, controlled by rheostats, instantly shaped the charge into a glowing ball of fire!

"Wow! A real hothead!" Bud wisecracked, trying to hide his excitement.

Tom grinned as he twirled several knobs and checked the gauges. The slightest variation in field strength triggered an instant response from the ball of energy. Mr. Swift tried exposing it to radio and repelatron waves. Each time the gauges showed a sensitive reaction.

"Looks as if we're in business, Dad!" Tom said jubilantly.

Bud left soon afterward as the two Swifts buckled down to work on the problem of perfecting an apparatus to simulate the human senses. Each concentrated on a different line of approach.

At noon they broke off briefly for a lunch wheeled in by Chow. Then silence settled again over the laboratory.

Tom had rigged up a jointed, clawlike mechanical arrangement with sensitive diaphragms in its "finger tips." The diaphragms were connected to a transistorized circuit designed to modulate the field current to the electromagnets.

Suddenly the young inventor looked up at his father with a glow of triumph.

"Dad, I just got a reaction to my sense-of-touch experiment!"



CHAPTER XVII

AN URGENT WARNING

Mr. Swift looked on eagerly as Tom explained and demonstrated his touch apparatus. By moving a pantograph control, Tom was able to manipulate the claws like a hand with fingers. Whenever they touched any material, the brain gauges instantly registered an electrical reaction inside the sphere.

The swing of a voltmeter needle showed how firmly the substance resisted the claw's touch, thus indicating its hardness or softness.

"With a computer device, such as we planted in Exman," Tom went on, "the brain would also be able to assimilate the textural pattern of any substance."

"Wonderful, son!" Mr. Swift exclaimed. "I hope I can do as well with this artificial sense of sight I'm working on."

Another hour went by before Mr. Swift was ready to test his own arrangement.

"You've probably heard of the experiments conducted with blind persons," he told Tom. "By stimulating the right part of their brain with a lead from a cathode-ray-tube device, an awareness of light and dark can be restored."

Tom nodded.

"Well, I'm using the same principle," Mr. Swift went on, "but with a sort of television camera scanning setup."

He asked Tom to draw the drapes and shut off the room lights, throwing the laboratory into complete darkness, except for the weirdly glowing "brain" in the glass sphere. Then Mr. Swift shone a flashlight at the scanner. The brain responded by glowing more brightly itself!

Next, after the drapes were opened again and the overhead fluorescent lights switched on, Mr. Swift painted a pattern of black-and-white stripes on a large piece of cardboard. He held this up to the scanner.

Visible ripples of brightness and less-brightness passed through the glowing ball of energy inside the sphere. It was reproducing the striped pattern!

"Dad, that's amazing!" Tom said with real admiration.

Mr. Swift shook his head. "Pretty crude, I'm afraid. The brain energy by itself can't take the place of a picture tube in a TV receiver. What we need is an analog computer to sum up the scanning pattern picked up by the camera tube and then pass this information along in code form."

Before Tom could comment, the alarm bell rang on the electronic brain. The Swifts dropped everything and rushed to the machine.

"Wonder if it's Exman?" Tom exclaimed.

The answer was quickly revealed as the keys began punching out the incoming message on tape. At the same time, a flow of strange mathematical symbols flashed, one after another, on the lighted oscilloscope screen mounted above the keyboard.

Tom and his father read the tape as it unreeled.

SPACE BEINGS TO SWIFTS. REQUEST INFORMATION ON PROGRESS AND RESULTS OF ENERGY SENT TO YOUR PLANET.

After a quick consultation with his father, Tom beamed out the reply:

WE ARE PLEASED WITH RESULTS SO FAR. FURTHER EXPERIMENTS NOW GOING ON. REQUEST VISIT TO CONTINUE LONGER THAN TWENTY-ONE DAYS AS PLANNED.

Hopefully the Swifts stood by the machine. Would their space friends agree? As the minutes went by without a response coming through, father and son exchanged anxious glances.

"They've got to let Exman stay, Dad!" Tom said.

Mr. Swift nodded. "I'm afraid, though, the space beings have decided otherwise. They—"

He was interrupted by the ringing of the alarm bell. "Message, Dad!" Tom said tersely.

A moment later they were overjoyed to see three words appear on the tape:

VISIT EXTENSION GRANTED.

Relieved, the two scientists went back to work on their sensing experiments. Twenty minutes later the signal bell rang again on the electronic brain.

"This time it must be Exman!" Tom cried.

The unreeling tape quickly bore out his guess.

EXMAN TO SWIFTS. TWENTY-FOUR-HOUR EARTHQUAKE UNDER HIGH LOYALTY.

"What!" Tom stared at the tape, his brow creased in a puzzled frown. "That 'twenty-four-hour earthquake' bit must mean he's warning us that a quake will occur in twenty-four hours. But what about the rest of it?"

"Hmm... 'Under high loyalty.'" Mr. Swift was as baffled as Tom. He studied the message for several minutes. It seemed highly unlikely that the electronic brain had made an error in decoding. Any new or untranslatable symbol caused a red light to flash on the machine.

"I think the only thing we can do is signal Exman and ask for a clarification, Tom," Mr. Swift decided at last.

Tom agreed. He beamed out a hasty code signal:

EXPLAIN MESSAGE.

Seconds later came Exman's reply. It was identical with the first message:

TWENTY-FOUR-HOUR EARTHQUAKE UNDER HIGH LOYALTY.

Tom and Mr. Swift stared at each other anxiously.

"Good night, Dad! This is horrible!" Tom exclaimed. "Exman sends us ample warning of a disaster and we're stymied!"



"Hi! What's going on, you two?" asked a merry voice. "More heavy thinking?"

Sandy Swift stood smiling in the doorway. The smile gave way to a look of concern as Tom explained the crisis.

"How dreadful!" Sandy gasped. "We must figure out what it means!... Wait a minute!"

Tom looked at her expectantly. "Got an idea, Sis?"

"Well..." The pretty, blond teen-ager hesitated. "You don't suppose Exman might have been translating some foreign words with a meaning similar to 'high loyalty'? For instance, high loyalty could mean 'good faith.' I know that in Latin 'good faith' would be bona fide."

"Sandy! You've guessed it!" Tom crossed the room in a single bound, gave his sister a quick hug, and whirled her around. "Exman must mean the Bona Fide Submarine Building Corporation! He didn't dare risk telling us the exact translation."

"Of course!" Mr. Swift was equally jubilant. But his face was grave as he added, "The company's located on the West Coast close to the San Andreas fault. Tom, a quake in that area could be devastating!"

"You're right, Dad," the young inventor replied. "I'll call Dr. Miles and Bernt Ahlgren at once!"

The telephone conversation that followed was grim with tension. Both government men begged Tom to take personal charge of the quake-deflection measures. Dr. Miles pointed out that tremors along the fault might trigger off a chain of quakes amounting to a national disaster.

After a hasty discussion, Tom agreed that he should station himself at the Colorado site, rather than at the West Coast Quakelizor installation. This would give him broader scope for damping out shock waves across the continent.

"I'll fly out immediately!" the young inventor promised.

Ahlgren, meanwhile, would flash orders to the Bona Fide Company and to civilian officials to have the entire area evacuated as soon as possible.

Hasty preparations were made for Tom's departure. He telephoned the airfield to have a jet plane with lifters readied for take-off. He also had Bud paged over the plant intercom. The copilot came on the run. When he heard the news, he was eager to accompany his pal.

"Listen, you two! I insist you have something to eat before you leave!" Sandy declared.

Tom was impatient over any delay. When Sandy proceeded to call Chow, the old Texan solved the problem by volunteering to go along as cook.

A short time later Chow came jouncing out to the airfield astride a motor scooter, hauling a cart loaded with supplies.

"Good grief!" Tom said, unable to suppress a grin. "We'll be back tomorrow, unless something goes wrong!"

"Bring food—that's my motto," Chow retorted, "like any good cook."

Minutes later, after a parting handshake from his father and a worried kiss from Sandy, Tom sent the sleek jet racing down the runway for take-off. Soon they were air-borne and heading westward. Chow served a tasty meal en route.

It was still daylight when the jet landed vertically in the Colorado canyon. The government crew manning the installation, and the Swift technician who had relieved Art Wiltessa as trouble shooter on the setup, greeted them eagerly.

"Looks as if we're in for a real test, Tom," said Mike Burrows, the engineer in charge.

"Let's hope we pass!" said Tom, holding up crossed fingers.

He checked every detail of the Quakelizor, power plant, and the communications gear. He opened an inspection panel in each of the dual-control spheres and tuned the kinetic-hydraulic units so as to step up the working pressure of the four powerful drivers.

"Well, all we can do now is wait," the young inventor muttered, wiping his arm across his forehead.

Tom passed the night in a fitful sleep, half expecting to be wakened at any moment by the stand-by crew on watch. No alarm occurred, however.

Dawn broke, and Chow delighted all hands with a hearty breakfast of bacon, eggs, and corn fritters. More hours of waiting dragged by.

"What time do you think the attack will occur?" Bud asked.

Tom shrugged. "The 'twenty-four-hour' business may have been approximate. But I'd say from two o'clock on is the danger period."

The young inventor checked frequently with Washington and the other crews stationed around the country. Suddenly the radiotelephone operator gave a yell.

"Your father is on the line, skipper!"

The scientist was calling from the receiver-computer headquarters at Enterprises. "Exman has reported a quake pulse will be sent in seven minutes—at 21.36 G.M.T."

"I'm ready, Dad," Tom said, then asked for various technical details before hanging up.

He passed the word to the crew and glanced at his watch. A hasty, last-moment inspection was carried out, every man checking certain details of the setup.

Soon the pulsemakers began ticking inside the dual-control spheres as they picked up the frequency signal by radio. Tom studied the gauge dials.

Tension mounted rapidly among the waiting group. The same thought was throbbing through every mind:

Was the nation on the brink of a terrible disaster? Or would Tom Swift's invention safeguard the threatened area?

As the deadline approached, Tom pushed a button. The mighty hydraulic drivers throbbed into action, sending out their pulse waves across the continent!



CHAPTER XVIII

EARTHQUAKE ISLAND

Now came the hardest part of all for Tom and his companions—waiting to learn if the shock deflectors had succeeded in blotting out the enemy quake wave.

No one spoke. As the silence deepened inside the cave, the suspense became almost unbearable. Minutes passed.

"When will we know, skipper?" a crewman ventured at last.

"Soon, I hope," Tom replied tersely.

But the waiting seemed endless. Bud's eyes met Tom's. The flier grinned and held up crossed fingers, just as Tom had done to Mike Burrows the previous evening. Tom managed a feeble grin in response.

Suddenly the telephone shrilled, shattering the silence of the cave. Tom snatched it from the radioman's hands.

"Tom Swift here!... Yes?... Thank heavens! I guess we can all be grateful, Dr. Miles!"

"Providence protected us, I'm sure, Tom," the seismologist replied at the other end of the line. "But in this instance it worked through Tom Swift's Quakelizors! The Bona Fide plant and the surrounding area never even felt the tremor—your quake deflectors worked perfectly!"

There was no need to tell the others. Tom's words on the telephone and the grin on his face told the story. A spontaneous volley of cheers echoed through the cave as he hung up. Then the crew crowded around to slap Tom on the back and shake his hand.

"I hope the whole country learns what you've done, Tom," Mike Burrows said. "If it doesn't, I'll be the first to spread the word as soon as the secrecy lid's taken off!"

"Shucks, I knew all along Tom's contraption would do the trick!" Chow boasted, glowing with pride over his young boss's achievement.

Tom could only smile happily. "Guess we can go home now," he said to Bud and Chow.

They were preparing to leave when another flash from Washington came over the radiotelephone. A ship's captain, five hundred miles out on the Pacific, had just reported sighting a great waterspout, accompanied by considerable wave turbulence.

"It could have been the spot where the enemy shock waves and our deflector waves met and damped out," Tom commented.

"Dr. Miles thinks so, too," the caller said.

Soon the sleek Swift jet was arrowing back across the continent. En route, Tom radioed word of his latest triumph to Mr. Swift. As always, he used the automatic scramblers to make sure any enemy eavesdroppers would pick up only static.

"Great work, son!" Mr. Swift congratulated Tom. "I was confident you could handle the situation with your Quakelizors."

"Thanks, Dad. See you soon."

When the jet finally landed at Enterprises and came to a halt on the runway, the control tower operator spoke over the radio.

"Harlan Ames would like to see Tom Jr. at the security building. He left word just a few minutes ago."

"Roger!" Tom replied.

Chow frugally carted off his leftover supplies. Tom and Bud, meanwhile, went by jeep across the plant grounds to security headquarters.

Ames greeted the two boys enthusiastically. "Nice going on that earthquake situation, Tom!" he said. "And now I have some more good news. We've just nabbed the man who imitated your father's voice over the phone the other night."

"What!" Both boys were excited, and Tom added eagerly, "Who is he?"

"An actor at the Shopton summer playhouse."

"How did you find out?" Tom asked.

"I had a hunch," Ames went on. "If the impersonator wasn't a plant employee at Enterprises, then he had to be a person with a trained voice. That gave me the idea of checking on all actors and station announcers here in the vicinity. It paid off right away. The guy's name is Brent Nolan."

"Have you questioned him yet?" Tom asked.

"I'm about to," Ames replied. "Radnor just brought him in."

The security chief led the way into an adjoining office. A slender, good-looking young man with blond wavy hair was seated on a chair with Phil Radnor on one side of him and a Shopton police officer on the other. The actor was visibly nervous and perspiring.

"This is Tom Swift Jr.," Ames told him. "Brent Nolan."

Nolan nodded. "Yes, I've seen your picture in the papers many times." The actor tried to force a smile but his face muscles twitched. "I—I seem to have pulled a pretty dumb stunt by faking that phone call from your father. I'm sorry."

"What was the reason?" Tom asked.

Nolan fingered his wavy blond hair uneasily and swallowed hard. "A man named Professor Runkle paid me to do it."

"Professor Runkle?" Tom frowned. The name seemed vaguely familiar.

"He spoke with a foreign accent. Said he was doing research at Grandyke University," Nolan explained. "He told me you might be expecting a rare biological specimen from the East Indies. He said both of you were eager to get hold of it for research purposes, but he was afraid that you had outbid him. However, if he asked you straight out, you would guard the secret very jealously. So he hired me to find out."

"Didn't it occur to you he might be an espionage agent?" Ames asked coldly.

Nolan seemed shocked. "Believe me, I had no such idea!" he averred. "Runkle seemed pleasant. He said it all was merely a short cut to save him from wasting any more time on the project. If Tom Swift had the specimen, he would quit. I—I guess I'm a little bit vain about the way I can mimic voices, and this gave me a chance to show off. Besides, I saw no harm in doing it."

"No harm?" Bud snorted. "You had Swift Enterprises in a real lather when we found out."

Nolan spread his hands in a helpless gesture. "I'm truly sorry," he repeated.

"How were you able to find out how my father's voice sounded?" Tom asked.

"I listened to a recording of a speech he made at the Fourth of July rally here in Shopton," Nolan explained. "I borrowed the tape from a local radio station. Guess that's how your security men got onto me."

"What did this fellow Runkle look like?" Ames asked.

Nolan thought for a moment. "Oh, he was past middle age, I should say. Grizzled hair, thick-lensed glasses. And he was quite heavy-set."

"Hmm. Then it certainly wasn't Narko," Ames murmured to Tom.

The young inventor nodded. "I believe I know him. The name just came back to me. I met a Professor Runkle in New York about a month ago, at a scientific convention. He was a member of the visiting Brungarian delegation."

"We'll check on him," Ames promised. He turned back sternly to the young actor. "All right, Nolan, I guess you can go. But I warn you—no more impersonations."

After more flustered apologies, the actor hurried out, obviously relieved.

"What a dumb egg he is!" Bud muttered.

"In a way he may have helped us," Tom pointed out. "If the Brungarian rebels hadn't found out about Exman, we couldn't have lured them into that kidnap plot. It's already helped us to save the Bona Fide Submarine Building Corporation."

Monday morning Ames reported that Professor Runkle had left the country. Tom was not sorry, since an arrest and public trial might have led to dangerous publicity about Exman. The probings of a sharp-tongued defense attorney might even have tipped off the Brungarian to Tom's real purpose in letting the space brain be hijacked.

Meanwhile, a telephone call from Washington announced that State Department men were flying to Enterprises to confer with the Swifts about taking official action against the Brungarian attacks. The group arrived by jet after lunch. Thurston of the CIA was also present.

"The problem is this," a State Department official said as they discussed the matter in the Swifts' office. "Should we bring charges against Brungaria before the United Nations? Or should we rely on other means, short of war, to block the Brungarian rebel coup?"

Mr. Swift frowned thoughtfully. "It might be difficult to prove they were responsible for the earthquake attacks," he pointed out.

"I'd say it's impossible," Tom said, "unless we give away the secret about our electronic spy." He paused, then added, "Sir, if the State Department will agree, I'd like more time before you make any official moves."

The Quakelizors, Tom argued, seemed to offer protection against any future quake waves, unless the power of the shocks was greatly stepped up. Meantime, working through Exman, Tom might be able to provide the Brungarian loyalists with valuable information. "I'm hoping it will help them overthrow the rebel clique and their brutal allied military bosses."

The State Department men conferred, then Thurston spoke up quietly, "In our opinion, it's worth a gamble."

After the group had left, the Swifts resumed their sensing experiments in Tom's private laboratory. They were hard at work when the signal bell suddenly rang on the electronic brain.

The two scientists rushed to read the incoming message. It said:

EXMAN TO SWIFTS. ONE ENEMY EARTHQUAKE PRODUCER IS AT...

Here the message gave precise latitude and longitude figures. It went on:

RUIN OF SWIFT PLACE IN ONE WEEK.

Tom and his father gasped in dismay. "I thought the New York-New England Quakelizor was going to protect us!" the young inventor exclaimed. "Our enemies must have located another earth fault with Enterprises right in its path!"

Hastily opening an atlas, Tom fingered the location of the proposed source of attack. It was Balala Island off the coast of Peru.

"Dad, that settles it!" Tom declared grimly. "It's clear now that those Brungarian rebels want to destroy us and use Exman in some way to conquer the earth!"

"I don't doubt that you're right, son," Mr. Swift said grimly. "We must act fast! But how?"

Again, the signal bell interrupted. This time, Exman gave a number of military details, evidently picked up from orders issuing from Brungarian rebel headquarters. They concerned incoming troop movements from the north and operational plans for crushing out the last pockets of resistance by loyal government forces.

Tom recorded them with TV tape, then snatched up the telephone and called the Central Intelligence Agency in Washington. He relayed the information from Exman and asked if American agents could transmit it to the loyalists.

"Don't worry. Well see that it reaches them," the CIA chief assured Tom. "Many thanks. This could have important consequences."

As Tom hung up he decided on a bold move. "Dad, I'm going to lead a raid on Balala!"

"A raid!" The elder scientist was electrified.

"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

A FIENDISH MACHINE

A chill of fear gripped Tom and his companions as they blinked helplessly in the glare! Had the enemy detected them the first moment they had set foot on Balala Island? Had they walked blindly into a trap?

Gradually Tom's eyes and those of his friends adjusted to the dazzling radiance. A door, blocking the tunnel just ahead, had slid open and the light was pouring out of a room beyond.

"What happened?" Arv gasped.

Tom pointed downward to a pedallike plunger inserted in the tunnel floor. "This must be a switch," he explained. "When I stepped on it accidentally, it must have opened the door and flashed on the lights."

Bud whistled. "Wow! Let's be thankful it wasn't a booby trap!"

"Maybe it is," murmured Hank grimly.

Steeling their nerves, and with every sense alert, the searchers advanced into the secret room.

Tom suddenly gave a cry of amazement. "The earthquake machine!"

A huge hydraulic device, with massive steel bed and supporting pillars, looking somewhat like the enormous body presses found in automobile plants, stood embedded in a recess in one wall.

Tom rushed to the machine and examined it in fascination. A powerful diesel generator stood nearby with banks of complicated electrical equipment, amid a spider-web tangle of wiring. Tom assumed this gear was for timing and synchronizing the shock waves. Evidently the whole setup was operated from a single control panel in the wall, studded with knobs and dials.

"What a job of design!" Tom exclaimed in awe. His eyes roved over every detail of the equipment while he poked here and there with his hands. He was getting the "feel" of the setup almost as much by touch and handling as by his superb technical intuition. "Boy, I hate to admire anything those Brungarian rebel scientists do, but this is really masterful!"