TOM SWIFT

"SWING the searchlight around, will you, Dad? I see something unusual!"

"Port or starboard?" asked Damon Swift.

"Starboard, just a few degrees," Tom replied. The lanky, blond-haired inventor was cruising with his distinguished scientist father about a hundred feet above the ocean floor near the Atlantic Ridge, the great jagged chain of undersea peaks that splits the broad Atlantic in two. They were in the realm of eternal night, far below the depths to which the sun’s rays penetrate.

Mr. Swift gasped in surprise as he swiveled the forward aqualamp, the powerful electronic searchlight mounted on the hull above their heads. In its sunlike glare a myriad of huge bubbles could be seen billowing upward in a steady stream from the ocean bottom. The stream appeared to be issuing from a small fissure near the base of a blocky mountain whose unusual shape, squat and almost flat-sided, had attracted their notice moments before.

"Great Scott! This is unbelievable!" the elder scientist exclaimed. "The way those bubbles are jetting upward—!"

"I’ve never seen anything like it!" Tom agreed, as he stared in fascination. "This could be a fantastic discovery!"

"Dad," Tom said, making some quick calculations in his head, "those bubbles might be helium gas!"

"You mean because of the tremendous speed with which they’re rising?" remarked Mr. Swift, who was as intrigued as his son by the phenomenon. "It hardly seems likely."

Tom pointed out, "Other bubbles we’ve seen so far have been just lazily drifting up."

"You have a point there," his father admitted excitedly.

"I didn’t know helium could be found underwater," remarked the third member of the expedition, Slim Davis. An experienced pilot for Swift Enterprises, the Swifts’ famed scientific and invention installation in Shopton, New York, Slim had recently completed a course of training in guiding the seacopter, Tom’s remarkable "underwater helicopter" capable of probing the aquatic depths with unequalled maneuverability.

"It’s rare anywhere on earth," Tom agreed. "But radioactive decay can produce pockets here and there. By the looks of it, this could be a big one—maybe the biggest ever discovered."

"You can tell that it’s helium just by looking?" Slim persisted.

Tom’s father answered as he gazed out the viewport. "It’s a possibility. Helium, because of its low density, is very buoyant. That would account for the bubbles’ fast-streaming action." The elder inventor's keen eyes glinted as he added, "Son, if your hunch is right, this could be a discovery of top scientific importance!"

Tom gave a tense nod. "I know. At present our country can get helium only from certain natural gas wells in Texas and Kansas. Those sources don’t produce a great deal, and may fail completely. If scientists had an unlimited supply from under the ocean—"

Tom grinned. "Right. It could be hydrogen, or argon or neon or other gases."

"Can’t you use the long-range spectrometer on it?" Slim suggested.

"The streaming motion fluctuates too much to get a fix," was Tom’s reply. "But," he declared firmly, "I intend to get the answer another way. I’ll go out in a Fat Man suit and collect a sample for testing!"

"I was about to suggest the same thing," said Mr. Swift. "In fact, I’ll accompany you, Tom. I’d like to take a closer look at the sea bed next to that fissure."

Tom steered the Sea Hound closer to the plume of hurtling bubbles. Then, pulling a lever on the control panel, he cut the steam-driven directional jets. The seacopter slowed to a halt as its whirring central rotors held the sleek red saucer suspended motionless in the ocean depths, holding it down against its buoyancy.

"Are you sure this is such a good idea?" objected Slim nervously. "I mean, we’re right next to the base of this mountain, and its sides look pretty steep. I heard about—"

Tom finished for him. "You’re thinking of what happened to the Ocean Arrow when we found the city of gold."

"Well—didn’t vibrations from the rotors bring down the side of a mountain on top of you?"

"You’re right to be concerned," Tom responded with a reassuring smile. "But we’ve made some improvements to the seacop’s design since then. On the Sea Hound our two central rotors automatically keep themselves in sync with one another. They pretty much cancel each other’s vibrations. And the redesigned rotor well has a damping effect."

"You needn’t worry, Slim," Damon Swift added. "We should be safe from anything short of an undersea earthquake."

As Slim took over the controls, Tom and his father crossed the small forward cabin to the hatchway that led to the airlock compartment, where the Fat Man suits were stored. This expanded chamber for underwater access was another new feature incorporated into the Sea Hound’s design.

His hand on the hatchway lever, Mr. Swift glanced at the dials and gauges that monitored exterior pressure and temperature. "Our deep-sea excursion will be under pressures higher than even the Fat Men are used to. But they should handle it without difficulty." As he stepped over the hatch threshold, he suggested over his shoulder, "You’ll want a float balloon in case you want to send up a marker, son. If the flow diminishes we might have a difficult time finding the exact site again."

"Good idea. I’ll take one." Tom unlocked a stowage compartment and took out one of the "balloons," which actually was a hollow metal sphere filled with compressed air, and which included a radio-and-sonar locating beacon. He attached this to a portable pack containing a great length of fine-gage nylon cable rolled about a drum with a self-winding mechanism. Finally he picked up a metal vacuum flask, self-sealing, in which he would collect the gas sample.

"Now to climb into the thing—not so easy a task for a grown-up," murmured Tom’s father, eyeing his Fat Man.

"Want some help, Dad?"

"No, I can manage."

The Fat Man suits were egg-shaped one-person submersibles, sporting robotic arms and legs and a reinforced transparent viewdome on top. Completely self-contained, they were designed to withstand crushing subsea pressures. The front halves of the suits stood open like books while stored side-by-side in the airlock chamber. The occupant was to step into his suit backwards, then swing it closed and seal it.

"Watch your step in the ooze out there," Tom warned his father as Damon Swift squirmed into his suit.

"Roger, Captain!" Mr. Swift replied. "That is—aye-aye."

As Tom switched on his air supply, he glanced at his father. His feeling of family pride was mixed with a slight twinge of disquiet. Seems funny to be doing this with Dad instead of Bud, he thought.

Bud Barclay, an athletic youth Tom’s own age, was the young inventor’s best friend and constant comrade. During a recent encounter with criminals while on Swift Enterprises business in New Guinea, both Bud and Slim Davis had suffered physically. Slim had quickly recovered, but Bud had born the brunt of the enemy’s electric-shock weapon, and the effects had run deeper than first suspected. A brief hospital stay had been extended, and Tom—not wanting to proceed with his planned trip to the sunken city in the absence of his pal—had opted instead to make a return visit to Earth’s tiny new moon Nestria, there to make scientific observations of a strange device left by extraterrestrials.

When Tom returned to the earth he had hoped to find Bud fully recovered. But although the young pilot had been released from the hospital, the company physician, Dr. Simpson, had directed Bud to take two further weeks of complete rest. When Tom offered to postpone his undersea trip a second time, Bud had insisted that his friend go ahead without him while Bud recuperated at the home of his parents in San Francisco.

Without Bud at his side Tom couldn’t help feeling a little lost.

In the forward compartment Slim shoved the control wheel and the seacopter descended gently to the bottom. A moment later the hatch in the ship’s hull opened and Tom stepped out, followed by his father.

The two aquanauts used the air-jets built into their suits to glide closer to the fissure in the ocean floor. Landing, they began waddling cautiously through the muck, making their way forward into the bright cone radiating from the aqualamp. Guided by its beam, they headed toward the source of the bubbles.

The ocean floor was completely barren of vegetation at this depth. The only signs of life were occasional glimmers of eerie light from strange-looking fish and other sea creatures flitting and hovering in the dark outside the lamp beam.

The bubbles were issuing furiously from a spot on the broad ledge they were now traversing. There the ooze seethed like a giant stewpot. On their left the ledge fell away sharply, the slope of the undersea mountain ending abruptly a couple dozen yards further below at a wide, flat plain.

"The geology of this area is odd," Mr. Swift mused over his suit sonophone. "I see signs of some recent volcanic activity." Tom agreed.

Tom and his father tested each step with the Fat Men’s thick metal legs, at the same time probing the sea floor with their own built-in suit searchlights. Finally coming within reach of the bubbling area, they separated. While Mr. Swift moved closer to the mountain on the far side of the jet of bubbles, Tom approached the fissure at the center of the roiling ooze and stood, braced but precariously balanced, just outside the uprushing stream.

Maneuvering the mechanical arms, Tom planted a self-digging spike in the bottom and released the marker buoy, which instantly fled upward out of sight. Then he upended the vacuum flask just as a bubble was forming and caught some of the gas neatly inside.

Suddenly the Fat Man began to wobble. It teetered precariously on its mechanical legs for a moment, then righted itself as the internal gyros brought the egg-shaped monster back into balance.

Hey, what goes on here? Tom wondered, feeling a slight twinge of alarm.

"Son, did you feel that?" sonophoned Mr. Swift, hidden on the far side of the foamy plume.

Tom had no chance to answer. The next instant a violent lurch threw him sideways, slamming him against the curving inner wall of the suit. Quickly Tom pressed his face against the plasti-quartz dome to see what was happening beneath his feet. To his horror, the ocean bottom was shuddering in a violent upheaval!

"Good night! Dad, we’d better get out of here fast!" Tom muttered half to himself. Then a new shock came, even more violent. Tom’s Fat Man suit momentarily lost its footing, tipping to the side.

"Tom! Mr. Swift!" sonophoned Slim Davis frantically. "It’s a seaquake! I’ll try to—" His words were lost in a confusion of static.

His keen eyes searching for a sign of his father, Tom gunned the minijets to propel his suit forward. But an upsurge of bubbles caught the Fat Man, rocking it from side to side. Tom desperately worked the controls, trying to keep the sub-suit upright. But then came another jolt as the whole sea floor seemed to explode! An immense geyser of water, gas, and mud erupted from below with the force of a dynamite blast. It struck Tom’s Fat Man and the seacopter, and hurled them upward.

Tom barely had time to glimpse the Sea Hound’s searchlight beam sweeping in a glittering arc when he was thrown backwards as the suit tumbled head over heels in the fierce uprush. His head crashed against the inner wall of the steel egg. With a moan of pain, the young inventor sank down, stunned.

When Tom achingly regained full consciousness, he found himself in total darkness. Only the glow of the instrument dials relieved the black gloom of the ocean depths.

The water around him was quiet now. Ever the scientist, Tom theorized that the geyser had been caused by the sudden release of a tremendous quantity of gas held under pressure somewhere beneath base of the mountain.

Whether he had been in stunned semiconsciousness for a few seconds or several minutes, Torn did not know. Though he seemed to be resting once again on the sea floor, he could see nothing through the impenetrable darkness of the depths. Only the reflection of his worried face looked back at him from the dome. Even the luminous fishes appeared to have been driven away.

"Where was Dad blown to?" he asked himself worriedly. "And how is he?"

Tom pressed the Fat Man’s exterior light switch, then flipped it back and forth in desperation. There was no response. "Oh, no!" he groaned. His searchlight was out of commission! Trying the sonophone, he received only static in answer to his calls.

Outside the crystal window there was no sign of his father or the Sea Hound’s beam. A wave of fear surged through Tom.

Steady, kid! he told himself. Getting panicky won’t help!

From the tactile-pressure indicator on the robot arm control panel, Tom could tell that the vacuum flask had been wrenched from his grasp by the undersea geyser. His valuable sample was gone, too! But there was no time to worry about that.

Working the controls cautiously, Tom maneuvered the Fat Man through a complete 360-degree turn. There was not a glimmer of light from the seacopter. Again and again he repeated his desperate but futile call into his sonophone mike. Getting no response, he finally gave up. Now what? Tom wondered fearfully.

Had the subocean upheaval breached the hulls of the Sea Hound and his father’s Fat Man suit? If so—Tom couldn’t bear the thought—Slim Davis and Mr. Swift were almost certainly dead!

ALONE and helpless in the depths of the sea, Tom pondered his desperate situation for a moment. Without help from the mother ship, his own plight was serious and his father’s might be worse. In any case, Tom decided, there was no point in lingering on the ocean bottom.

"Well, here goes," he determined, speaking to himself aloud. His words rang hollow and strange inside the metal-rimmed airspace.

Switching off the electronic buoyancy controller and opening a valve by hand, he blew his suit’s ballast tanks and prepared to surface. An elevator feeling in the pit of his stomach told him the Fat Man was zooming upward through the murky depths.

Slowly the blackness outside his curving viewpane lightened into gray. Then the water took on greenish tinges, which finally deepened into a rich blue-green. Tom was somehow comforted by the fish of all description that darted past. Seconds later he broke through the surface with a mighty bound.

"Oh boy, that old sunshine looks good!" Tom exulted.

Peering around, he gave a cry of joy. Less than a hundred yards away, the Sea Hound was wallowing in the waves. The float balloon, marking the location of the gas fissure and bearing a small fluttering pennant, was also in sight.

He was startled as his speaker erupted with, "Tom, is that you? Are you all right?"

"I’m okay, Slim."

"Wish I could say the same," was the reply. "I was thrown against the control board and knocked for a loop. What about your Dad?"

"I—I don’t know," Tom faltered. Suddenly he was struck by a hopeful thought. "But wait—I only came to the surface because I blew my ballast tank. If Dad were knocked out—"

"Right!" exclaimed Slim. "He could be safe in his suit but unconscious, down on the bottom somewhere! Come aboard and I’ll submerge again."

Just then Tom jumped in alarm at a strange metallic sound coming from the wall next to his elbow. Turning around, he saw a small metal cylinder floating close by, the waves knocking it against the Fat Man. The gas sample! Made buoyant by the gas it contained, the flask had drifted up to the surface.

After retrieving the container, Tom steered the Fat Man toward the seacopter, keeping his eyes on the sea around him for any sign that his father had surfaced, perhaps some distance away. A chill of foreboding came over him when he failed to glimpse any trace of the bulbous sub-suit.

Tom rapped on the seacopter’s side-hatch, and it popped open under Slim’s control. In minutes the Sea Hound was again plunging down beneath the waves into the darkness below.

The seacopter followed the sharp outline of the undersea mountain to its base, where Tom and Slim could again see the column of rushing bubbles, now broader. The seaquake appeared to have opened the fissure wider.

Slim swept the aqualamp right and left across the sea floor, and brought the craft’s second lamp into play as well. "I don’t see anything, Tom," Slim reported solemnly.

"Dad’s suit might have been buried in the muck," Tom declared. "If so, the SRL should show his location." The sono-resonance locator was an invention of Tom’s which pinpointed solid, hollow underwater objects by inducing and detecting a characteristic "signature" through sonar-type waves.

Tom adjusted the instrument. "This’ll only work if he isn’t buried too deeply," he commented grimly. "Cross your fingers, Slim."

Almost immediately, the device gave forth a hopeful buzzing sound. "Got him!" Slim exclaimed. Following the indication on the dial, the Sea Hound approached the base of the mountain, about one hundred yards beyond the gas geyser. A mechanical metal hand protruded limply from the sea-bottom mud!

Determinedly taking command of the situation, Tom used the seacopter’s steam jets to stir up the loose mud and blast it aside. Mr. Swift’s Fat Man suit was soon revealed to view in the murky cloud of particles. Tom donned his suit again, and in minutes he had dragged his father’s suit aboard and pulled the unconscious occupant out into the air. Damon Swift was unconscious, the side of his head badly bruised in two places.

Smelling salts brought about a flutter of eyelids and a weak, choking gasp from Mr. Swift’s lips. "Don’t try to talk, Dad," urged Tom, his face white. "We’ll get you to a hospital in nothing flat."

Surfacing and reversing the pitch of its prop-blades, the Sea Hound raced for the nearest port at jet speed, riding its cushion of air a few feet above the rolling waves. Within the hour, Mr. Swift was stable, alert, and sitting upright in a hospital bed in the city of Hamilton, capital of the island of Bermuda.

"His injuries are not too serious, young fellow," said the doctor, standing next to the bed. "A very mild concussion, with no significant subdural hemorrhaging. But you were wise to bring him to us so promptly."

Tom thanked the doctor and clutched his father’s hand, relieved.

For the time being, there was nothing for Tom to do but wait and hope that further tests would disclose no hidden injuries. As the minutes dragged by into hours, the young inventor thought ruefully of the many times when he himself had come face to face with death, not only at sea, but in the desert of New Mexico, the frozen wastes of the Antarctic, and the bleakness of outer space. In his latest adventure, he had used his advanced ultrasonic cycloplane to outwit an unprincipled, avaricious scientist seeking riches in the New Guinea jungle, heedless of the cost to human life. Now Tom was reminded that his projects also put those closest to him in danger.

But all medical signs were positive, and by late afternoon of the following day Tom and Damon Swift had returned to Shopton by means of the Sky Queen, Tom’s mammoth Flying Lab, while Slim Davis piloted the Sea Hound to its berth on Fearing Island off the coast of Georgia.

Arriving home at last, Tom left his father in the care of his mother and sister Sandra, then drove back to Swift Enterprises. He was anxious to test the composition of the gas sample, which he had carried along with him on the Sky Queen.

Checking into the office he shared with his father, the metal flask in hand, he was delighted to find Bud waiting for him.

As they shared a bear hug, Tom exclaimed, "Didn’t expect to see you back till next Monday, flyboy!"

"When Sandy phoned me about your Dad, I figured I’d had enough of rich food and little cable cars ‘climbing halfway to the stars’," replied the dark-haired youth jokingly. "Besides, I feel fine. But how’s your Dad doing?"

Tom gave Bud the reassuring reports, and described the mystery of the undersea mountain and their exciting discovery. "Leave it to you to turn up something wild wherever you go! So if it turns out to be helium, it’s a major find? How come? Is Enterprises planning to get into the party-balloon business?"

Grinning, Tom replied, "Helium’s valuable for quite a bit more than balloons. Nowadays liquified helium, the coldest common substance known, is used to supercool electronic circuits to improve conductivity and make them more sensitive. A plentiful source of the gas would be a real boon to scientific research, and could have big technological implications, too."

"I see," said the young pilot thoughtfully. "And since it’s in international waters, the U.S.A. had better be the firstest with the mostest. But how in the world do you plan on tapping a gas well at the bottom of the ocean? I mean, this goes way beyond undersea oil drilling, Tom."

"You’re right, chum. But I have a few ideas."

"You usually do," Bud pronounced. "No, correction—you always do!"

Tom winked and stepped over to the wall, where he touched a button. A combination worktable and drafting board slid out from the wall, silently. Tom picked up a sheet of stiff paper on which a number of sketches had been made. "Remember this?"

Bud nodded. "Sure do. You showed it to me in the hospital—if I wasn’t just hallucinating. It’s the pressurized dome you want to set up in the city of gold, for underwater work teams to live in."

"That’s right. I call it a hydrodome—hydro means—"

"I know, genius boy. Water. A guy has to know Greek and Latin to work around here!" Bud took the sketch and looked it over again. The proposed structure was a round, bulging tank of metal, about sixty feet in diameter, dotted with circular portholes of the same composite of quartz and Tomasite plastic, called Tomaquartz, used in Swift undersea craft. Deep-sea researchers in protective gear along the lines of the Fat Man suits would use the hydrodome as a workspace and living area while investigating the submarine city and its environs, remaining beneath the sea for weeks or months at a time. They would come and go through an airlock, and oxygen for breathing would be extracted directly from seawater by a new invention of Tom’s. "So what’s the idea? Are you planning to put up a hydrodome next to the helium well?"

"That’s what I’m thinking," confirmed the young inventor. "Of course the depth is much greater, and there could be some other problems, but that’s the direction I’m heading in at present." He added that for the moment he would put exploring the sunken city on the back burner. "This helium-well project needs to have top priority."

"Are you sure it’s helium?"

"Come with me, pal, and I’ll test it out!"

The twosome took a ridewalk moving ramp to the chemical technologies building, where Tom released the contents of the flask into the storage chamber of an electron-wave analysis instrument patented as the Swift Spectroscope. Studying the output, a broad grin of excitement inched across Tom’s face. "It’s helium, all right, and very pure too! This is wonderful!"

"Still," remarked Bud doubtfully, "all that water…"

"It’ll be a tough nut to crack," Tom agreed.

Back in Tom’s office, the two close friends chatted about Bud’s vacation in his home town. "Nothing earthshaking," he said. "My Mom and Dad are well, and I spent some time with big brother Dave and big sister Shelley. ’Bout the only interesting thing happened just before I flew back."

"Tell me," Tom urged, and Bud began to narrate the story.

One day, as the California sun had slouched toward twilight, Bud, dressed-up for an evening at the theater, had found himself with free time on his hands. Deciding on impulse to push the envelope a bit, he had wandered into the bar adjoining the lobby of the San Francisco Holliston, an elegant old downtown hotel. "I wondered if I’d be carded," Bud said to Tom. "But the bartender didn’t blink an eye, even when I asked for a softdrink."

As he sat sipping his drink—and hiding it with his hand—an attractive young woman some ten years Bud’s senior had drifted down gracefully onto the bar stool next to him. She was well-dressed and well-coiffed, and just as Bud was noticing these facts she turned his way and said hello. Casual conversation grew lengthier ("Really, I was just being polite," Bud explained.) and finally the woman, Amelia, asked Bud if he’d care to join her later in the evening for dinner. Her tone, and the glint in her eyes, suggested that she had more in mind than friendly conversation.

"I really can’t," the youth had said, trying not to turn red or sound flustered. "I have plans—theater tickets."

"Then tomorrow night," Amelia had persisted.

"Listen, I—I’m really flattered, ma’am, but—see, I—"

She had rolled her eyes, not in hurt disappointment but in wry resignation. "I see. San Francisco! I’m definitely fishing in the wrong waters."

Bud had laughed. "No, no, it’s just that—I’m not really as old as you think I am. I’m staying with my folks, in fact, and…" He had lowered his voice. "Actually, I shouldn’t even be sitting here."

"Oh my. You’re that young? Here I thought you were just cute." She had laughed gently—but still with a certain rueful tone.

"I’d say she saw through your sportcoat right down to those football shoulders of yours," commented Tom. "She had you pegged as an athlete who likes to play for fun!"

"Yeah," Bud admitted. "I can’t help it, you know. But she was a nice lady. She laughed at my jokes. Now that’s important, Tom!"

Eventually Bud had explained that he lived in Shopton, New York, and was employed as a pilot by the famous Swift Enterprises invention firm. "I’ve even been up in space with Tom Swift," he had said immodestly.

"Up there?" She had pointed out the window. At the end of a canyon of tall buildings, a bright bead of light was illuminating the darkening sky. "Some day, when I have grandchildren, I’ll tell ’em that when old Grandma was a little girl there was only one moon in the sky. They probably won’t believe me."

"Uh-huh. I was on the Nestria expedition, actually," was Bud’s suave reply. The boasting lamp is on, he thought.

"You know," she had said after a pause, "this may be fate working its wonders. I was planning a move to the east coast. I’m not satisfied with my work here at the U.S. Attorney’s office. Do you suppose Swift Enterprises would be interested in a lawyer with a background in patent law and commercial contracts?"

"I don’t know," Bud had said. "I don’t think I’ve ever met the Enterprises lawyer, but I know he has a staff working under him. If you’d like, I’d be glad to—"

But she already had a card in her hand, which she had pressed into Bud’s. "You’ll pass this along, won’t you, little boy?"

"I promised her I would, Tom," Bud concluded.

"I’ll give her card to Willis Rodellin," Tom said, holding out his hand. Glancing at the name on the card, he frowned.

"Something wrong, skipper?" Bud asked.

After a thoughtful silence, Tom shrugged. "No. It’s just that her name kind of rings a bell. I don’t know why. Maybe I read about one of her court cases somewhere. I guess that’s not too unlikely, if she deals in patents and the like."

"Well," said Bud, "if it’s her last name that’s got your attention, I asked her if she had any relatives in the instant-coffee business—but it’s the wrong spelling."

"I’ll pass along the card," Tom promised. But his face still wore a thoughtful expression as he set the card down on his desk, face up. The card read:

AMELIA K. FOGER, ESQ.

This was one time Tom Swift would have done well to have recalled some details of Swift family history!

WHEN TOM returned home for dinner that evening, he was pleased to see that his father was up and around. Except for a couple ugly bruises peeping out from behind the bandages on the scientist’s face, he was every bit his usual energetic self.

Awaiting supper, the two sat in the den and spoke of the events of the last couple days. "I’m afraid this fouls up our trip to the city of gold, son," Mr. Swift said with a wry smile.

"Never mind that, Dad," Tom replied. "The important thing is that you’re all right. And as far as science is concerned, finding a major new source of helium is more than enough!"

"You’ve tested the sample?" asked Mr. Swift eagerly.

"Yes, and the Swift Spectroscope confirms it."

"Fine, fine," his father said. He drummed his fingers on the arm of his chair, then added, "Tom, we’d better notify the government of this at once. It’s too important to keep to ourselves."

"I certainly agree," Tom replied with earnest enthusiasm. "Whom should I contact?"

"Bronson at the Bureau of Mines. He’s in charge of all helium production. I’ve dealt with him before. Enterprises, and the Swift Construction Company, have a history with that office that goes back to your great-grandfather’s time." Mr. Swift was referring to Tom’s famous namesake, the first Tom Swift.

"I’ll call him first thing in the morning, Dad," Tom promised.

The next day found Tom in the Enterprises teleconference room, sitting across a table from the televised image of Assistant Director Leo Bronson. When Tom reported the undersea discovery, the gray-haired government official was very enthusiastic. "If everything pans out, this find of yours could be significant indeed, along the lines of your discoveries in Antarctica, Africa, and the rare-earths mine in New Guinea. You gentlemen certainly are keeping us busy! If we could organize production on a large scale, it would revolutionize half a dozen fields of research and development! For example, cargo-carrying balloons would be much cheaper than the present system of freight-carrying planes, and they could make use of the jetstream—so I’m told. And besides the obvious technological uses to which helium might be put, it would really expedite our space-flight program!" Bronson declared.

"The space program?" Tom puckered his brow. "What’s the connection, sir? Is the government planning to use helium balloons?" Remembering Bud’s comment about party-balloons, the young inventor smiled.

Bronson’s image nodded. "Not such a far-fetched idea, Tom—you yourself make use of buoyancy in your underwater launch system in—what’s that island called?"

"Loonaui, sir." Swift Enterprises used an aquatic lift stage to launch spacecraft to the orbiting Enterprises space station from a base in the mid-Pacific.

"On some of the future rocket and satellite launchings, we think helium balloons will be used as a booster stage. In other words, the launching platform will be raised to the outer limits of the atmosphere by means of these balloons. Gets us above the thick part of the air, you know."

"That will save fuel," Tom agreed, "but it will take immense quantities of helium if the method is widely used."

"That’s just it!" Bronson said. "We need a new source of helium in a hurry and this undersea bed could be the answer. Listen, Tom, let’s all work hand-in-glove on this. I’ll have some of our deep-sea Navy boys look the site over and do their own analysis—just a formality, you understand. Meanwhile, I’ll put together a liaison team to keep Enterprises connected to us. They’ll work with you directly and report to my office. Sound good?"

Tom groaned inwardly but replied, "That’s fine, sir." Swift Enterprises had not always had a positive experience working "hand-in-glove" with government agencies and officials.

During the ensuing week Tom applied himself to several scientific projects. The preeminent task was to adapt his hydrodome design to the necessities of longterm work at a much greater depth than anticipated. The sturdy material he had intended to use, a lightweight combination of Tomasite plastic sandwiched between layers of magtritanium alloy, proved too weak to withstand the terrific pressures found at the base of the undersea mountain. Extended over that many square yards, the dome would crumple at a touch, Tom thought glumly. But what can we use? He experimented with Tomaquartz for a time, but found that the substance could not be manufactured in the large sheets required. Guess I’ll have to rethink the overall configuration of the dome, he concluded.

To give his mind a break from the immediate problem, the young inventor turned his attention to the data he had collected on the satellite Nestria during his recent trip there in his rocket ship the Star Spear. Enjoying the freedom of movement guaranteed by his atmosphere-making machine, which had produced a livable earthlike environment on the tiny asteroid, Tom had spent several days in a cave studying the artifacts left there for him by his mysterious space friends, extraterrestrials who communicated with Earth via deep-space radio.

The main subject of Tom’s studies was a cube-shaped device of peculiar composition which appeared to function as the key component of a "gravity concentrator" affecting the entire moonlet. The cube was fastened to the cave floor by some unknown means and could not be moved; furthermore, it was impervious to x-rays and other such instrumental probing. Yet Tom had been able to study the energies that flowed around it, energies which also coursed through the veins of bright crystal that suffused the crust of Nestria. Tom had named this strange semi-metallic substance Lunite, in recognition of the satellite’s original nickname, Little Luna.

One afternoon Tom, joined by Bud, was hard at work in one of Enterprises’ shielded high-energy lab chambers, setting up a sample of Lunite in a strong viselike clamp. Above, attached to a wall, was a spherical device, black in color.

"You sure you want to do this, genius boy?" Bud asked nervously. "Last time you tried that generex machine on stuff from space, we just about dissolved like a cold remedy in a glass of water!"

"Pal, that window pane is made of ten layers of Tomaquartz with sheets of Inertite sandwiched between. I can’t believe anything could get through it!" Then Tom chuckled. "Besides, I’m holding the cut-off button in my hand. If you feel anything vital melting, let me know!"

"I’ll do that," replied the young pilot. "My signal will be a high-pitched shriek."

Sealing the test chamber the youths withdrew to positions in front of the observation window and Tom activated the all-frequency wave generator at its lowest power setting. There was no detectable response from the Lunite sample. After examining some monitoring instruments, he began to gradually increase the generex output, upping the power click by click.

"Tom, d-do you feel something?" Bud asked. "Kind of a tickling sensation?"

"No I don’t," replied the scientist-inventor absently, deeply concentrating on his work. "But the polarization scanners are showing some kind of field activity in the air around the rock sample. This could be an important clue to how that gravity device works, Bud." He touched a control knob. "Hmm! Getting a big response to slight frequency changes… and the field seems to be expanding."

He touched the knob again.

Suddenly a sharp, distant sound caused both Bud and Tom to look behind them, toward the locked laboratory door. "What was that?" Bud demanded. "You heard it too!"

Tom nodded. "Sounds like someone talking loud, Bud, that’s all. Nothing to worry about." But at Bud’s nervous urging Tom shut down the generex and took a look out into the hall.

"I mighta knowed!" exclaimed a foghorn voice. "You’re at one o’ them experiments o’ yours agin, sure as shootin’!"

The voice issued from the generously sized mouth and double-chinned throat of Chow Winkler, a hefty older man who was not only chef to Tom and the rest of the Enterprises senior staff, but a close personal friend who never failed to lift the young inventor’s spirits.

"What’s wrong, Chow?" Tom called to the ex-Texan, who stood several doors down in the building hallway, a tray in hand.

"Brand my jumpin’ beans, why ast me?" grumped the cook. "Not like I know anythin’ about this here scientistical foolishness." He strode closer to Tom and Bud on his high-heeled western boots, and held out his tray for them to examine. "Look’t that salt-shaker! Whatter y’see, boys?"

A large glass salt shaker stood in the middle of the tray. "I, er, don’t see anything, Chow," Bud said. Tom nodded his agreement, eyebrows raised.

"Durn straight, a-cause they’s nothin’ to see! Here I am, walkin’ along, bringin’ a nice little afternoon snack t’ Franzenberg and his gang, when all of a sudden blame if’n my salt shaker don’t decide to jump up in the air like a hop-toad!"

"Jump in the air? What do you mean?" Tom asked.

"Mean what I say, boss. Jumped right up off’n the tray. If’n I warn’t so quick on the draw, she’d o’ shot right acrosst into the wall. But I snagged her with m’ right hand."

"Well, pard," said Tom soothingly, "maybe you just took a misstep, or bumped against—"

"Nawp!" Chow insisted. "Nothin’ like that—jest took off on its own. And then when I grabbed it, all th’ dang salt went flyin’ away!"

Bud gave a half-shrug. "Too bad. Got all over the floor, hm?"

The westerner’s face turned almost as red as the scarf around his neck. "Buddy boy, yew jest don’t get it! I didn’t say fallin’, I said flyin’! Tom, that there salt sprayed right through them little holes like they’s jet-propelled, ever’ bit of it! An’ that’s the last I saw of it!"

Tom took a moment to examine the floor and walls of the hallway, rubbing a wetted finger along them.

Bud asked, "Anything there? Ghostly ectoplasm, maybe?"

Tom gave a tentative shake of his head, but frowned thoughtfully. "If there’s any salt here, it’s not a shaker-full—just a few grains here and there."

"No surprise," Chow pronounced. "That salt was flyin’ like no tomorrow. Must be half-way down th’ hall and out the door!"

Tom had no answer to the mystery. "I don’t see how my running tests on Lunite could have affected your salt shaker, Chow. Or even just the salt."

Just then Tom’s pocket cellphone bleeped, its rhythm indicating an interoffice call from within Enterprises. "This is George Dilling, Tom," came the familiar voice of the plant’s office of communications and public interest. "The airfield tower asked me to contact you. That jet flight you’ve been expecting has just landed."

Tom replied, "I’ll meet them in the office; Dad’s already there. Have Security check their ID’s and show them the way, won’t you, George?" Apologizing to Chow and promising to investigate further, Tom headed for the nearest ridewalk, Bud following at Tom’s invitation.

In the Swifts’ shared office in the ultramodern administration building, Tom and his father shook hands with their two visitors, Leo Bronson’s appointed liaisons for the helium operation. One was a rugged, balding man of about fifty with a tanned, weather-beaten face. The other, in his late twenties, was dark-haired and wiry in build. Wary at first, some instinct told Tom he could trust them.

The older man, Dr. Arthur Clisby, was a well-known Bureau chemist whom Mr. Swift had met before. "And this is my associate, Bob Anchor," Dr. Clisby said crisply, introducing his companion.

"Glad to know you," said Tom, shaking hands. "And this is Bud Barclay. Would you like to have a look at that helium sample right away?"

To Tom’s surprise Dr. Clisby shook his head negatively. "That won’t be necessary, Tom. Bob and I have examined the spectroscopic data you transmitted to the Bureau, as well as a fresh sample taken by the Navy sub team."

He frowned unexpectedly, and a moment of ominous silence followed.

"Is something wrong with the sample, Arthur?" Mr. Swift asked.

Bob Anchor answered the inquiry. "I’d say so. Your sample doesn’t match the one the Navy acquired. There’s not a trace of helium coming from that site you marked!"

"What!" gasped Tom unbelievingly. "That’s not possible!"

"It’s a fact," said Dr. Clisby. "And I’m sorry to say—but obliged to inform you—that Bob and I are here to investigate the possibility that your company has been a party to a deliberate hoax targeting the government of the United States!"

DAMON SWIFT flushed with anger. "That’s absolutely absurd! To speak bluntly, the reputation of Swift Enterprises for honesty is a good deal higher than the current—"

"We know, we know," interjected Bob Anchor hastily. "I think Arthur’s tone reflects his, his sheer disbelief at this situation we’re in—all of us."

Bud had his familiar thundercloud look, but forced himself to say nothing, backing away. Tom took a calming tone. "Let’s review the facts, shall we?"

"Of course," said Clisby. He had begun to look somewhat abashed. "A Navy cruiser, one of our specialized scientific vessels, arrived at the site roughly twenty hours ago, guided by your floating marker buoy. A small deep-water submersible, a drone, descended to the point where the cable was anchored in the sea floor near the base of the mountain. A stream of bubbles was issuing, just as you had described. The drone took several samples of those bubbles, and returned them to the ship. A preliminary analysis, right on board, was most disturbing; but no firm conclusions were drawn. At the base in Norfolk, we ourselves conducted an independent analysis and the preliminary findings were confirmed."

"What findings, precisely?" asked Mr. Swift.

"The samples tested positive for argon, hydrogen, water vapor, methane, and various sulfides. There was not a trace—not a trace!—of helium gas."

"I can’t understand it," Tom said.

"Nor I," added his father. "Our own analysis was absolutely indubitable."

Tom rubbed his chin. "Is there any possibility that your samples were switched somehow?" he asked Clisby and Anchor.

Bob Anchor shrugged. "If so, we don’t see how it could have been done, or by whom. Everyone involved had a high level of security clearance."

"And besides," noted Clisby, "the containers were marked in code. Damon, I’m sure you know that our department takes as much care in these matters as your own people do."

Tom and his father, utterly dismayed and thoroughly baffled, exchanged frowning glances. Tom broke the leaden silence. "Gentlemen, would you be willing to accompany us back to the site in the seacopter? Using our deep-water suits, you could take fresh samples yourselves, and test them on the spot with your own equipment."

Both visitors smiled. "Actually, that’s precisely what we were hoping for," Dr. Clisby admitted. "We want to give your company every chance to disprove these allegations."

"Much as I would like to accompany you, my doctor has other ideas," Mr. Swift declared. "But my son and his pilot, Bud Barclay here, can handle this without me."

Tom said, "Let’s not wait. It’s only mid-afternoon, and we can have supper on Fearing Island—that’s where the Sea Hound is docked." The plan was agreed to with enthusiasm all the way around, and before the next hour struck Tom and Bud were spearing southward in the Flying Lab with their guests.

"I’m afraid I came off rather poorly," remarked Dr. Clisby to Tom and Bud in the control compartment. "There’s no pleasant way to convey to a friend what amounts to an accusation."

"No hard feelings, sir," Tom replied.

"I’ll save my hard feelings for whoever’s behind this snafu," muttered Bud.

"Well, at least we’ve found an excuse to ride in this wonderful airship of yours, Tom," Bob Anchor said. "I’ve dreamed of it ever since your Montaguaya trip made the front pages!"

After a smooth vertical landing at thumb-shaped Fearing Island, the four had a light supper and took off immediately for the mid-Atlantic in the Sea Hound. Bob Anchor, who had served a post-college hitch in the Air Force, was wide-eyed and impressed. "Tom, if your helium strike pans out half as well as this baby, it’ll be a rip-snorter!" he exclaimed.

"Wait’ll you see this hound dive!" Bud told him with a chuckle.

It was coming on nine PM local time when the seacopter settled down onto the dark blue waves near the buoy with its tossing pennant. Tom reversed the blade pitch and the remarkable craft dove beneath the scalloped carpet of the surface and down into the black depths. Using the aqualamp they followed the cable down to the bottom.

Dr. Clisby marveled at the strange, phosphorescent fishes that darted past the cabin window. "Fantastic scene!" he exclaimed in a voice muffled by awe.

As Bud held the Sea Hound steady, Bob Anchor pointed. "There it is, just as it was on the video from the drone." A line of big bubbles issued steadily from the muck at the mountain’s broad base.

Tom did not respond for a moment. When he did, his voice was perplexed—and grim. "Bob—Dr. Clisby—something’s very wrong here. This is not the spot where I planted the buoy cable the other day!"

"I knew it!" yelped Bud.

"Not the spot?" Dr. Clisby was amazed! "How can that be, Tom? The signal from the buoy—"

"The signal’s right, but the location’s wrong," Tom responded. "The anchoring spike has been moved somehow. There was a drop-off next to the real site. It was still there after the seaquake, when we went down to find my father. There’s nothing like that here."

"Maybe we can find the bubbles from the real site," Bud urged. He guided the seacopter along the base of the undersea mountain, slowly and expertly. But as meter after meter of gray-brown sea floor fell away, Tom’s heart sank toward his stomach. There was no sign of the helium well!

Suddenly, as the Sea Hound rounded an outcropping, Tom gripped his pal’s shoulder. "Bud—stop! That ledge ahead—I’m sure that’s the right spot!"

As Bud played the aqualamp beam over the side of the mountain and the ocean floor, Bob Anchor cried out, "There’s the helium spot! I can see the bubbles!"

Relieved cheers filled the small cabin as the four gazed at the steady upsurge of gas. "Look at the speed of their ascent!" Dr. Clisby murmured in awe. "Nothing like the other stream! And now that I see it, I feel certain it’s helium, Tom, just as you and your father said."

"You’ll have to make sure, Dr. Clisby," Tom responded with a slight twinkle in his eye. "We want no more, er, disputes. There’s a Fat Man suit waiting for you."

"Ah, yes. Well…" He glanced in the direction of his more youthful assistant.

"Not a problem, Arthur," laughed Bob Anchor. After some quick instruction, Anchor and Tom went out and captured fresh samples of the rushing bubbles. Back aboard, Tom invited the scientists to make an immediate preliminary analysis with the portable test equipment they had brought with them. The two chemists eagerly repeated their earlier analysis with their chemical and spectrometric apparatus. When they finished, the visitors’ faces were tense with excitement.

"Incredible!" gasped Dr. Clisby. "This is almost one hundred percent pure helium!"

Bob Anchor ripped off his protective apron and said jubilantly, "The Swifts were right all along!" He added soberly, "Can you and your father ever forgive us for our suspicions, Tom?"

"You had good reason," Tom replied. "What I find unforgivable—and mysterious—is the moving of that line-anchor. It couldn’t possibly have happened by accident."

"But who could have been responsible?" asked Dr. Clisby. "Does Swift Enterprises have enemies?"

Bud threw Clisby a sourly ironic look. "Is the ocean wet?"

"Well," said Clisby, "perhaps we ought to set that issue aside for the present. I must confess that I’m less interested in the practical applications of this discovery than in its genesis. Some very peculiar geochemistry must be occurring beneath this mountain, producing gas pockets in wide variety. Normally, of course, geolithic helium deposits are associated with radioactive decomposition…"

"Yet we’ve detected no sign of radiation," noted Tom thoughtfully. "Not so far, at least. Something may turn up in further exploratory operations."

"You mean to start with a preliminary survey?" Dr. Clisby asked.

Smiling, Tom shook his head negatively. "Why wait? We know something’s down there! I’d like to start the main drilling immediately, using my atomic earth blaster."

"Great!" exclaimed Dr. Clisby, and Bob Anchor nodded. Both men were familiar with Tom’s earth blaster, the remarkable tunneling machine which he had invented to tap a new source of iron at the South Pole. "However," the senior chemist went on, "what about capping the flow if the drilling proves successful?"

"I’ve thought of that," Tom replied. "My gadget must be strong enough to stand up against a geyser. Last evening I had Arvid Hanson, my chief modelmaker, put together a prototype of a special well-capping device that I’ve come up with. Here’s the principle."

Pulling out a pencil, he made a quick sketch of his arrangement. Both government chemists gave admiring approval.

"If a chemist’s point of view is of any relevance, your device should work perfectly!" said Dr. Clisby. "Well, I’m certainly in favor of commencing as soon as possible to find out the extent and depth of these wells. I shall so indicate in my report to Assistant Secretary Bronson. Of course the expedition must be kept secret until the United States has staked an official claim."

"So far, no one outside Swift Enterprises and the Bureau of Mines knows about the discovery," Tom assured him. "And we’ll keep it that way!"

Tom turned, about to direct Bud to bring the seacopter to the surface. He stopped himself in mid-breath. "Hmm!"

"What, skipper?" asked Bud.

"Just looking at the automatic spectrometer readout, pal." The young inventor flicked a couple switches on the control board, and used a dial to adjust the display. "Bob—Dr. Clisby—I know you’re familiar with the Swift Spectroscope. Take a look at this."

The chemists approached, gazing intently at the colored bar-lines on the readout screen. "What area is the instrument scanning right now?" inquired Bob Anchor.

"It’s undirected," was the reply. "Just pointing straight out into the water."

Dr. Clisby’s forehead creased with perplexity. "But this—this shouldn’t be, surely. Compounds of this complexity would never develop in open water."

"They’re synthetic," Tom declared. "In fact, correct me if I’m wrong, but don’t these look to you like cholinergic chain disruptors? I’m hardly an expert, but I happen to recall the general form."

"You’re not wrong, Tom," said Bob.

"Excuse me, guys," Bud interjected. "My only contact with chemistry was when I punted a football right through the chem lab window. What are we talking about?"

As Tom took a few steps away, running a hand through his blond crewcut, Dr. Clisby answered Bud’s question.

"What are we talking about? Poison, Bud—some of the deadliest poisons known to man!"

BUD BARCLAY turned pale. "Poison! Man-made?"

Tom nodded. "Definitely. These readings indicate the presence of a tremendously potent neurotoxin, a nerve agent absolutely fatal even in very minute quantities, even highly diluted. There was extensive journal coverage of it several years ago. Though the actual formula was kept top secret, a certain amount of identifying data was given out to research companies worldwide, for their own protection and the protection of the public. That’s how I know enough to recognize it."

"Thanavassyn-9-Epsilon—T-9-E! Great God almighty!" breathed Dr. Clisby in dismay. "Imagine the consequences if—"

"But, w-we’re not in danger here in the ship, are we?" Bud asked, eyebrows high.

"No, Bud," said Bob Anchor. "We’re sealed in, as we were in the diving suits. But if just one drop of the seawater out there had managed to get into the cabin and evaporate—"

Tom cut him off with a cry of fear! "The Fat Man suits! We brought in plenty of water clinging to their outer shells!"

"And with the sample container as well!" gasped Bob.

"Don’t panic," counseled Clisby. "We’re showing no signs of a reaction. Let’s look at the data in a bit more detail." He, Tom, and Bob spent several tense minutes poring over the figures produced by the spectroscope computer as Bud watched, alert to every faltering beat of his heart.

Finally the three men nodded at one another and Clisby said: "It appears the complex sulfides in the water—from the other gas geyser, and no doubt many smaller sources yet to be detected—have reduced the compound to a less potent variant. We’re safe."

"But a permanent mining operation would have long-term exposure," Tom pronounced. "It could hardly be helped. We’ve got to figure out the source."

"It may not take all that much figuring," said Bud quietly. "Look at the sonarscope."

"What is it, another sub?" asked Bob.

Tom nodded. "A big one. Rounding the mountain at a higher elevation, about… almost two miles distant." Tom switched the sonarscope display to its imaging mode. "Look at that! Anybody recognize it?"

The image, white-on-black like a photo negative, showed a strange, bulbous craft unlike anything the submariners had seen before. The fore part of the ship resembled a football with a snubbed-off nose. This was attached to a longer, much narrower trailing section of cylindrical form.

"Like a whale!" murmured Bud. "A real Mad Moby! It’s huge, Tom."

"The front section alone is more than twice as long as the Sea Hound, fore to aft," declared the young inventor. He pressed a button, activating a recorder to preserve the sonarscope data for later study.

"Do you intend to challenge her?" asked Bob Anchor.

"If she’s involved in spreading that neurotoxin, I just want to get us out of here!" Tom took over the controls and the seacopter sped away from the undersea mountain at top speed. The mystery visitor did not give chase, and in minutes the Sea Hound had risen to the surface and taken to the air.

"All very disturbing," muttered Arthur Clisby.

Bud gulped. "I’m proof of that!"

Returning at last to Fearing Island, Tom immediately contacted federal and naval authorities, alerting them to the presence of the toxin and the possibility that an unidentified submersible was involved in its release. He concluded by transmitting to them the recorded data from both sonarscope and spectroscope. After a troubled night’s sleep, the four flew on the Sky Queen back to Shopton, where Dr. Clisby and Bob Anchor would be residing for the duration of the helium project start-up, working with company scientists.

At Swift Enterprises Tom made a detailed report to his father in the office of Harlan Ames, the plant’s chief of security. "I’ll examine those sonar images, and see what my intelligence contacts have to say," Ames promised. "I’m not aware of any foreign nation roving the seas at such depth, in something of such a peculiar design. I can’t see what makes it go. Can you?"

Tom shrugged. "My guess would be some kind of electromagnetic reaction drive—utilizing the electrical conduction properties of the surrounding water, in other words. That’s been around for decades, you know. But obviously the bigger concern is the toxin business."

"Yes, and it’s not just a danger to your helium hydrodome, either. If even a small quantity of T-9-E got caught up in a cross-oceanic current, it could cause a worldwide catastrophe—many thousands of deaths." Ames thought for a minute, silent, as Tom and Mr. Swift waited patiently. "And yet—why would an enemy release trace amounts in the water, enough to be detectable and give away the game, but not enough to cause any harm?"

"They may not have realized that the other dissolved chemicals would weaken it," Tom suggested. "Or, I suppose it could have been some sort of industrial-waste accident."

"If so," said the security man grimly, "whoever is responsible will have every reason to cover it up! And given the high stakes, don’t think murder won’t cross their minds."

Damon Swift sighed. "I know you’re right, Harlan. Looks like this son of mine has managed to hand you yet another in an endless series of mortal crises."

"Don’t worry. That’s what ulcers were invented for."

As Tom and his father rose to leave and return to their own private office next door, Ames waved them back down into their chairs. "And there’s something else, gentlemen."

As the Swifts settled back down, Ames took out a manila folder and opened it on his desk. "Tom, you passed along to the legal office the card of this woman Bud met in San Francisco."

"Uh-huh. I thought Willis Rodellin might have an opening to fill."

"He does, as a matter of fact. He contacted her and received back a full resume, faxed. And then he asked me to do a background check."

"Did something problematic come up?" asked Mr. Swift. "I don’t need to review the matter personally, Harlan—Willis makes the decision."

"In this particular case you might want to get involved yourself."

"Why?" inquired Tom in surprise.

"That name of hers doesn’t ring any alarm bells for you two? Not you, Damon?"

"Her name?" Tom’s father frowned. "I don’t think Tom mentioned the name to me, actually."

"I don’t recall it, to tell the truth," Tom said. "I just handed off the card."

A wry, half-amused expression on his face, Ames turned the folder around and pushed it in front of his two employers. Mr. Swift glanced at it—and reacted. "Good grief—Foger! Are you trying to tell me—"

"The man was her great-uncle, her grandfather’s brother."

Tom was bemused. "Who are we talking about?"

"We’re talking about a man—a boy, I suppose—by the name of Andy Foger."

Tom shook his head. "I guess the name does seem a little familiar, Dad. But I don’t recall the details. Something to do with Great-Grandfather Tom?"

Damon Swift chuckled. "Quite a bit ‘to do’!" He began to relate the story of the first Tom Swift’s conflict with Andy Foger, and as he did so his son began to remember what he had read and heard over the years.

Young Andy Foger, red-haired, squinty, and generally ill-tempered, was what some described as a pampered youth. The son of a local bank official, he had been in essence a spoiled rich kid able to afford anything he wanted, including a circle of friends willing to put up with him while professing adoration. He became something of the town bully, a pest to the police but protected by his father from any consequences, the well-deserved ones in particular.

When Tom Swift, whose father Barton was already an important name in Shopton, began to tool about on his first invention, a motorcycle, Andy’s jealousy boiled over. He commenced a years-long campaign of rivalry, mischief, innuendo, and outright sabotage against the increasingly famous boy inventor. Finally, he and his father, who had fallen on hard times, were publicly disgraced by their participation in what amounted to a smuggling operation.

"A sad case," commented Mr. Swift. "A prominent family spiralling down into criminality. Even the fact that your great-grandfather saved his life didn’t alter his resentment."

"What became of him, Dad?"

Harlan Ames responded. "I’ve done a bit of research. The Foger family seems to have moved away from Shopton around 1915—probably the smartest thing they could have done. There’s some evidence they moved to Mexico. I found an obit for someone of the right age, same middle initial, in Mexico City, dated September 3, 1960. If it’s the same Andrew E. Foger, it looks like he ended up working in the petroleum industry."

"Any mention of a wife? Children?" Mr. Swift inquired.

"None. But a cyber-trip to the Hall of Records allowed me to verify a younger half-brother, who lived with his mother in Mansburg —Amelia Foger’s grandfather. He’s deceased as well."

Tom rubbed his chin. "This is interesting stuff, but—do you think it matters much, Harlan? We’re talking about animosities between two families that are almost a century in the past. Amelia’s running into Bud looks like just a coincidence."

"Yes," Ames conceded. "And it’s true that she did nothing to try to conceal her name from us. She may know nothing about her great-uncle’s early life."

Damon Swift laughed gently. "I wouldn’t want to be held to account for my ancestor, poor Professor Blondlot."

Tom joined in the laughter. "Nor I, for good old ‘Dead-Horse Longstreet’!" Turning sober, he added, "But if Miss Foger decides to pursue the position here at Enterprises, maybe I’ll have a chat with her some day about family history—a friendly chat."

"From Bud’s account," remarked Ames with a wink, "Amelia Foger is very easy to be friendly to!" The next day he was able to report to the Swifts that upon Mr. Swift’s concurrence the San Francisco attorney had been offered the position in the legal office, and had accepted. She would be arranging a temporary living situation in Shopton, relocating immediately.

During the week that followed, Tom pursued various aspects of the helium-well project. Always in the back of his mind was the menace of the neurotoxin and the unidentified sub. Bud’s characteristic nickname for the phantom, Mad Moby, had caught on with everyone associated with the project, including Arthur Clisby and Bob Anchor.

While Hank Sterling’s engineering section completed the full-sized version of Tom’s well-capping mechanism, the young inventor worked with Arvid Hanson to develop a prototype for a newer, stronger hydrodome. The deep-sea habitat had now assumed a more hemispherical shape, though still completely closed off at the bottom. No longer made primarily of metal, the improved version was a dome comprised of a myriad of flat facets arrayed in geodesic form. The dome was now entirely of multi-layered Tomaquartz and transparent all around, with a complex internal structure of metal supports.

When the small prototype was finished, a crane lowered it into one of the huge block-shaped pressure tanks used at Enterprises to test experimental submersibles—the seacopter, Fat Man suit, and Tom’s earlier jetmarine.

"How optimistic are you feeling, Tom?" Arv asked, eyeing the dimlit image of the hydrodome on the tank’s interior monitor.

"Optimistic? I’ll cop to feeling confident!" was the smiling reply. "But we’ll have to get the confidence-meter up to one-hundred-percent before we risk letting people live in that thing."

Hanson agreed, and signaled the tank operator, Wes Beale, to commence increasing the inner pressure. A red line, like that on a thermometer, began its maddeningly slow creep up the control board. "Looks good," muttered Arv presently. "Already a good fifteen percent over the max test pressure of the earlier model."

"And she’s still standing tall," Tom said. "How’s the air pressure inside the dome?"

"Holding firm," was the reply. "And not a trace of moisture."

"Thank goodness!" Tom chuckled, his face aglow with the excitement of a scientific victory in the making. "I wouldn’t want to have to bother with an umbrella when—"

Suddenly the watchers gave a start as a loud alarm siren erupted in a piercing wail of warning! Before anyone could even ask a question, an explosive thundercrack split the air, and a narrow plume of white froth jetted skyward from one side of the test tank.

"The tank!" screeched Wes Beale, turning to run. "She’s gonna blow!"

ARV HANSON whirled and had run several steps after Beale when he realized that Tom was hanging back. He paused and yelled over his shoulder, "Tom! Come on!"

But Tom Swift resisted the panic that had overwhelmed the other two. His skillful hands darted over the test tank control board. Suddenly the jet of water diminished markedly, then began to gradually wither away, as did the automatic alarm siren.

Wes and Arv came trotting back to Tom’s side, somewhat shamefaced. "Tell me how you did that, chief!" demanded Wes. "There’s no way to drop the pressure that rapidly!"

"One way, Wes," said the young inventor. "I blew the main sealer flanges on the hydrodome model."

"You mean you flooded it?" asked Arv in amazement.

Tom nodded soberly. "Had to. Letting the tank water expand into the space reduced the overall pressure to below critical. If we’d let the side wall fracture, the pressure would have hit us like a piledriver—even on the run."

"Good grief!" Wes exclaimed with an admiring half-laugh. "There’s a solution that wouldn’t have occurred to me in a million years."

Hanson put a hand on his young boss’s shoulder. "You saved us, all right. But the dome prototype is ruined. We’ll have to start from scratch."

"Don’t bother," Tom said quietly. "Look at these numbers—the final readings before I flooded her."

Arv read them off with a wince. "The dome structure had started deforming at the middle of the facets."

Tom nodded. "The support props couldn’t handle it. If we’d kept upping the pressure, the hydrodome would have collapsed." He gave a sigh of discouragement. "I don’t have a clue as to how to proceed further. It won’t be practical to try to work that site living in Fat Man suits and submarines, not in the long run." He gave his friends a rueful look. "I guess the helium project will turn out to be just a pipe dream after all."

"What I’d like to know is—what caused the tank to fail like that?" muttered Wes. "The material is inspected thoroughly by the TeleTec machine before each use."

"Including this time?" Tom inquired. "Are you absolutely sure?"

Wes proceeded to make a series of calls. Eventually he reported to Tom that the mandatory inspection had not taken place. "It’s my responsibility," he said. "But I don’t understand what happened. I remember informing the team, by the usual instant-messaging alert, that we were going to do a Level 8 test today. I even have an automatic acknowledgement message on my computer, showing that the message went through. Yet there’s no trace at the other end, and my guys deny that they were ever informed. And they’re an honest bunch, Tom."

Thinking of his mysterious foes, the crew of the Mad Moby, Tom asked Wes if any of his team were new hires, or newly assigned. "Not a one," Wes insisted. "We’ve all worked together for years now."

"Then it’s unexplained," Tom declared; "just like the moving of that buoy anchor. But please forward to me whatever you find out when you analyze the tank wall. It’s quite a coincidence, failing like that on an occasion where any weakness wouldn’t have been caught in advance."

Though Tom was baffled and discouraged, Clisby and Anchor, as well as his father and the ever-enthusiastic Bud, urged him to proceed with other aspects of the helium well project. "Chum, you’re sure to figure a way around this roadblock—you work best under pressure!" Bud exclaimed.

Tom gave him a sharp look. "Under pressure? That’s got to be one of those notorious Barclay puns!"

"Maybe," admitted the dark-haired pilot. "It’s gotten so bad my mouth does it even when I’m not paying attention!"

Tom agreed to continue whatever forward motion he could make.

Soon enough came the day to drill at the base of the mountain. Returning to the site in the Sea Hound with Bud, Clisby, Anchor, and chief engineer Hank Sterling, Tom used his earth-probing penetradar system to determine the overall shape and depth of the natural fissure and the likely location of the chain of interconnected gas pockets. "Man, is it deep down, and right under the mountain!" Tom pronounced. "But we should be able to go at it at an angle."

"And, as they say—how’s the water out there?" asked Clisby.

"No sign of the toxin for miles around," said the young inventor. "No sign of Mad Moby, either."

"Unless he’s in hiding," noted Hank.

After selecting a spot for drilling on the plain just below the ledge, they unloaded the earth blaster’s compact launching platform from a stowage bay that opened to the exterior, and fastened it into the rock below the ooze with spread anchors. Next, the torpedo-shaped machine itself was maneuvered into place and quickly set up.

"Because of the likelihood of pockets of flammable gases in the area, we’ll be using the ‘cool’ mechanical version instead of the ‘hot’ arc-field model," Hank explained in answer to an objection from Bud.

Then the extravehicular team—Tom, Bob Anchor, and Hank Sterling—worked on the capping mechanism, which sat atop the launching platform at first. It would be drawn down into its final position as the blaster was released. To keep the well-capper in place, they shot rocket anchors into the bedrock. The nozzle, initially open, would be closed gradually, until the device sealed itself.

"All set now. Stand back!" Tom warned his two companions by suit sonophone. "I only hope we don’t set off another geyser!"

When the men reported back that they were in a safe position, Tom signaled the blaster to switch on its powerful engines. With a thudding roar audible even within the Fat Man suits, the blaster bored into the sea floor, raising an inky cloud that billowed and swirled like a subsea cyclone. Dazzled by the reflected glare from the disturbed particles, the three turned off the searchlights in their Fat Man suits. In the yellow-white cone of the seacopter’s penetrating aqualamp beam, made visible in order to assist the workers, they watched the flow of gases freed by the blaster surging in greater and greater quantities through the open well-cap.

Suddenly the Sea Hound’s light blinked off and on, as if in a warning signal. Surprised, Tom asked over his mike, "Bud, what’s—?"

He stopped short as the searchlight went off again—and stayed off. Danger! He shut down the blaster, which by now had completely disappeared under the sea floor. Then Tom told his companions to keep their lights out.

Everyone waited tensely.

A few seconds later the small sonarscope in Tom’s suit reported a signal bounceback that made him stiffen with apprehension. An underwater craft was coming rapidly toward them from the south!

Tom was certain the marauder was the phantom Mad Moby. Could it be carrying the deadly neurotoxin?

Of one thing he was sure: He did not want to be seen at the secret project! He switched the sonophone output to its minimum setting. Over his mike he told his companions in an electronic whisper: "Lie down flat! Camouflage yourselves! Don’t move!"

Obediently the two grotesque-looking Fat Men followed Tom’s example as he worked the controls of his suit so that it stretched out on the ocean bottom, partially covered in the settling ooze stirred up by the earth blaster.

As the three waited in worried silence, the strange submarine came on steadily and passed like a massive shadow within a few hundred yards of the three prospectors, showing no lights, no portholes, no sign of life within. Only its passage in front of the phosphorescence of the darting marine life revealed its presence to the eye.

In a minute the eerie specter had vanished into the deep-sea gloom.

Tom now switched on his suit lights and slowly worked the robotic arms and legs to bring his Fat Man upright again. The other two were soon standing up also. To Tom’s alarmed amazement, the Sea Hound was gone!

"Where did it go?" he puzzled aloud. "Bud, can you read me?"

Over the sonophone Hank Sterling asked urgently, "What about that sub? Was it the Moby?"

"It must’ve been," Tom replied.

As he spoke, a light flashed on across the subsea plain and drew closer. The enemy? Tom’s heart leaped with relief as he recognized the outlines of the Sea Hound!

"Everyone okay out there?" came Bud’s familiar voice over the sonophone.

"I am," Tom told him. "Hank?"

"Check," was the reply.

"How about you, Bob?"

The young chemist responded that he was all right but thoroughly mystified by the unknown submarine.

"Aren’t we all!" Bud chuckled, "That’s why I ducked out of sight. Tom, whoever these guys are, they must’ve got wind of your planned operations here!"

"It sure looks that way," Tom admitted in a worried voice. "Still, it’s possible that this all has nothing to do with the helium well. They may be involved in some other kind of research—or something illegal—and could be keeping tabs on the general area electronically. Anything on your scope, Sea Hound?"

"As Chow would say, She went a-goin’ round the mountain when she went! We can’t see her—she can’t see us."

"So let’s get on with the drilling."

"Roger!" Bud replied. "I mean—"

"Never mind!" Tom chuckled.

The tubular capping device was already in place at the top the hole cut by the blaster. The power was turned on and the capper ground itself solidly into the underlying rock. Once again Tom remotely closed the circuit to the blaster’s atom-power plant and the machine responded instantly, resuming its angled boring into the sea floor. Several minutes later a hissing roar, deep and muffled, reverberated through the dark waters and the ocean bed itself.

"We’ve struck gas, I think!" Tom cried out to his companions jubilantly.

Now came an especially delicate part of the drilling operation. Handling the controls deftly, Tom brought the blaster zooming backward up to the top of the shaft on its spiked guide-wheels. There was a noise like a cork being pulled from a fizzy champagne bottle as the blaster cleared the surface of the sea floor. Then a terrific geyser of helium gas came thundering upward through the aperture of the cap!

"There she is, skipper! Nice going!" Bud cheered from the Sea Hound.

Dr. Clisby added his congratulations. "I’ll await the sample, but it’s obviously helium, Tom. Magnificent work!"

Tom turned the controls that closed off the well, stopping the flow of gas from beneath the undersea mountain. Then the work crew stowed the earth blaster away in the seacop’s exterior hold.

After the three took a last look at the capping mechanism, sealed and silent, Tom was flushed with happiness and sheer relief. He sonophoned the other aquanauts to return to the seacopter—the work was done for the day.

His words were cut short by a strangled cry. "Help! S-something’s gone wrong with my air supply!" It was Bob Anchor’s voice. "I can’t b-breathe! I’m losing—"

The call died away in a choking gasp!

"QUICK! We must get him back to the ship!" Tom urged Hank.

In agonized suspense the two jetted through the water as fast as they could to their friend’s side. Through the viewdome they could see Bob’s eyes bulging, his face turning reddish purple!

"We’ve got to hurry!" Tom urged. A stark fear welled up from the back of his mind.

Tom and Hank desperately grasped the helpless form in their metal hands, standing on either side. As they half-carried, half-dragged Bob’s Fat Man toward the seacopter, Tom noted with thanks that Bud, overhearing the crisis, had steered the Sea Hound nearer and opened the aquatic hatch. Bob was roughly thrust aboard and the hatch sealed behind them. As the water in the lock was pumped away, Tom ordered Bud to keep the inner hatch tightly closed.

"We don’t know what we’re dealing with," he murmured. Bud and Dr. Clisby grasped his unuttered meaning.

Tom and Hank remained sealed in their own suits as a precaution while they used the emergency release lever to force open Bob’s suit. The scientist lay collapsed against his safety restraints. His mouth hung open. For a terrible moment Tom felt certain he was not alive. But then Anchor’s chest heaved and he began gasping for air.

"Can you hear me?" Tom asked over his suit’s external speaker.

Bob forced a nod, his eyes fluttering open. "I’m all right!" he mouthed weakly.

Dr. Clisby was observing them through the small port in the airlock hatch, his face gray with fear for his colleague. Holding a microphone to his lips, he told them: "His reaction does not indicate an effect of the toxin. I’m testing the water and air… yes, it appears to be safe." At Tom’s okay, the hatch to the cabin was opened and Bud and Clisby rushed in to help Bob while Tom and Hank wriggled out of their suits.

Bob was carried to the aft cabin of the seacopter, where a bunk was folded down from the curving bulkhead for him to rest on. As Tom rushed to his side, he gave the young inventor a pained, apologetic look. "I don’t know what happened out there," he said. "I couldn’t catch my breath—guess I panicked."

"No one could blame you," offered Dr. Clisby gently. Tom could sense the warm affection between the two scientists.

"What went wrong?" Bud queried.

"Something happened to his air supply," Tom replied. Taking a small kit of tools, he crawled inside the defective Fat Man and tinkered for several minutes.

"Flutter valve was jammed shut," he announced as he emerged from the suit. "But it’s fixed now."

Hank Sterling received Tom’s news with a frown of disbelief. "Those valves are checked and cleaned regularly. It’s standard procedure."

Tom gave a wry nod. "Right. And it was standard procedure to inspect the pressure tank walls, too."

"It’s no accident," declared Bud firmly. "The Moby gang plans to get us all out of the picture any way they can!" Tom could only respond with a shrug.

The near-tragic accident was temporarily forgotten when the group excitedly discussed the helium strike on the mountain shelf. "Judging by the quantity of gas bubbles, this whole area is loaded with helium!" Bob Anchor declared.

"Fine," said Bud. "Now genius boy here has to work some inventive magic so we can work the mine!"

Tom said nothing, deep in thought. An astonishing idea had suddenly burst upon his inventive mind! He turned to the controls and began guiding the seacopter back to Fearing Island, where the Sky Queen awaited them.

Day after day Tom’s family and friends found him preoccupied, in a mood of quiet intensity. When his mother expressed some motherly concern, he explained that he was trying to work out "a very strange solution" to the vexing challenge of setting up a permanent workers’ camp at the deep-sea helium site. "If I’m right, Mom—if it works—the whole problem of pressure will be behind us! It’ll revolutionize man’s ability to work in the depths of the ocean!" But he politely refused to describe his invention.

One evening, as Tom worked late at Enterprises once again, Damon and Anne Swift discussed the matter in the Swift living room as Sandy listened, playing with her pet cockatiel Featherbee.

"What happens if he just can’t solve the problem?" asked Mrs. Swift. "Our son is brilliant, but some things just can’t be done. We never taught him to accept that."

Mr. Swift nodded. "I never could either—neither could my Grandfather Tom. In the blood, I suppose." He turned to Sandy. "And as for you, sweetheart, I think you’re blessed with the same streak of stubbornness—aren’t you still trying to crack the Jack the Ripper case?" Sandy’s love of true-crime mysteries was a family joke.

"Don’t think I’m not making progress, Daddy," she replied blithely. "As for bringing brother Tom back to earth, I have a plan—but it needs the approval of the Swift Enterprises CEO." She smiled sweetly and ominously.

The day following, a warm afternoon, two figures hopped off the Enterprises ridewalk in front of the immersion dynamics laboratory, a large free-standing structure at the outskirts of the plant near the observatory dome. They were garbed in shorts and bright-colored sweatshirts, their eyes masked by stylish sunglasses.

"We really don’t want to walk in on him, Sandra," said Bashalli Prandit with a toss of her long raven-black hair. "Not that he does not deserve to be interrupted. But it would not be a proper ambush."

"Daddy called Tom up to the office," replied Sandy. "Just before you arrived—late!—he told me by cellphone Tom was on his way. He’ll keep him there for twenty minutes—long enough for us to slip into the pool." Sandy took the small electri-key her father had left for her and aimed it at the door to the building. It popped open with a slight beep. Sandy entered and switched on the overhead fluorescent tubes.

Tom had been working steadily in this building for several days, trying to perfect a mysterious new invention that required testing in a large body of salt water that replicated the general composition of the mid-Atlantic. His sister and Bashalli, a young Pakistani who was a close family friend, were determined to startle the young inventor away from his labors for an afternoon of fun on Lake Carlopa. Here the Swifts maintained a sleek little sailboat, the Mary Nestor.

"Now what do you suppose that is?" asked Bashalli as she followed Sandy into the lab. Next to the north wall, about twenty feet from the edge of the pool, an open metal framework had been set up. It appeared firmly bolted to the concrete floor. At the top of the framework tower, held in place by clamps, was an odd-looking jumble of electronics equipment trailing down thick power cables. A knob-studded control console stood nearby, a silent blank-faced sentinel.

"Oh, that must be what Tom is working on—his new water invention," said Sandy, pulling off her sweatshirt to reveal her swim top. "Ugh! I hope he improves the look of it before he puts it on the market."

"Do you know what it does?"

"Not a clue, Bashi. Don’t you hate it when boys play coy?"

The girls removed their shoes and outer clothing, stashing them out of sight.

Carrying a small beanbag intended for playing catch in the water, Sandy approached the edge of the immersion pool—as large and deep as a conventional swimming pool—and gazed down into the clear water. "Oh dear, we’ve made a mistake. This isn’t salt water at all. It’s some kind of acid! Can’t you smell it? Well, I guess we’ll—ohhh!" Arms whirling, she tumbled into the water with what was calculated to sound like a dire shriek.

Bashalli approached her floundering friend. "That was hardly convincing, Sandra. I recommend that you keep your day job."

Sandy responded by splashing her crony. "You’re just heartless. Come in—it’s a little cool but not too bad. Like the ocean. Oh—switch off the lights first."

Bashalli complied, then used the railed steps to slip gracefully into the pool. The only light in the lab came from some illuminated dials on the control board. That was fine with the girls. They intended to lie in wait for Tom in the water, then pop up with a banshee cry when the young inventor switched on the lights.

Alert to any sound of their quarry at the door, they played catch with the beanbag, which was designed to float in the water. There were many misses, but their eyes slowly became accustomed to the relative darkness.

"Where do you suppose he is?" asked Bashalli after many minutes had crept by.

"Oh, I don’t know. You know Tom—always saving the world. Here!" Sandy sent Bashalli a long, high toss. But she had badly miscalculated: it arced over the Pakistani’s head and whapped against the framework tower with a loud clang!, flopping down onto the control board next to the tower.

A string of tiny lights flickered to life on the console.

"Sandra, I am not so sure Tom will be delighted with our prank," murmured Bashalli nervously.

"We just have to shut it off again," asserted Sandy with much more confidence than she felt.

Suddenly both girls gasped in surprise. A strange sensation swept over them, a sort of tingling pressure on their skin. "Sandy! I—I’m—"

"Me too!" cried Sandy Swift in alarm, stumbling backwards along the pool bottom.

Choking, badly frightened, the girls fought against the smothering force, trying desperately to keep their heads up above the waterline. Feet flat on the bottom they pushed upward with their legs, summoning all their strength. Even so, they could barely withstand the downward pressure. Barely able to keep their faces above water, in minutes they would crumple from fatigue—and drown!

They emitted several screams, but the effort sapped their strength.

"B-Bashi, I’m so—so sorry I—" Then Sandy slipped down another inch and her mouth was beneath the water. Bashi was already immersed to just above her nostrils. She thrashed and struggled for breath.

The lab door opened a crack, then wider. Dazzling sunlight slanted through the room, cut off almost instantly as the door was pulled quietly shut. The girls tried to cry out to the figure, but the effort was useless; they could only manage muffled whimpers as they struggled to stay conscious, to not abandon the fight to live. Their shoulders ached from the dead weight of their arms and hands, forced down to their sides.

The figure did not bother to take a glance at the two pale ovals in the black of the pool. His face covered by a pull-down ski mask, he strode purposefully across the floor to Tom’s invention. He paused as if examining it. Then he reached deep into a pocket and withdrew a length of heavy pipe.

Swinging in a wide, vicious arc, the intruder attacked the machine with a savage fury!

SANDY SWIFT was swimming upstream.

The stream was as wide and as long as a river, and it angled upwards into the sky. She could see through its glassy sides easily. Shopton was below—there was the house; there was Commerce Avenue—but becoming tiny and distant as she mounted higher. The horizon was curving, but the wrong way, like the back of a saddle. She was struggling. Her arms ached and her head throbbed. But she dared not give up.

Someone was hanging on to her ankles.

It was Bashalli, she knew. Poor Bashalli. She heard the Pakistani coughing, a choking, racking cough. Oh Bashalli, stop! she pleaded. You’re shaking me! It occurred to her, oddly, that it was she herself who was coughing.

Something, someone, reached down through the water and pulled her up into the harsh thin air by the back of her neck. Then a pale yellow light flooded over her.

As Sandy awoke and finally knew she was awake, the first thing she noticed was a faint odor of ether and antiseptic. Her eyelids flickered open and she saw a white coverlet and the rungs of a metal bedstead. With a start, Sandy struggled bolt upright. She was in the Enterprises infirmary!

"Thank heavens you’ve regained consciousness, darling!" murmured a voice nearby. Mr. Swift gripped his daughter’s hand. Then the young plotter realized that her whole family was clustered around the bedside, with Doc Simpson, the plant’s youthful medic, in the background. She forced a wan smile and felt the oxygen mask strapped to her chin.

"We’ve been so worried about you, dear!" her mother said, bending down to kiss her cheek. "Even though Doc Simpson says that you’ll be all right." Tom, his face white, patted her shoulder and nodded.

The medic smiled reassuringly. "Yes, she will be, Mrs. Swift." Then, grinning, he added, "If there’s one thing I’ve learned around here, it’s that you Swifts are hard to keep down!"

Stepping forward, the young physician took Sandy’s wrist and glanced at his watch. Seconds later he said, "Pulse rate normal. Feel hungry?" Sandy indicated the breathing mask, and he gently removed it.

"Don’t worry about me!" she gasped weakly. "Bashalli—what about Bashalli?"

"I am over here," called a shaky voice from the other side of the infirmary. "I will be well when Bud stops squeezing my wrist!"

"Doc says you’re both fine," Tom declared. "You two took in so much water Shopton Water and Power’s charging you an excess usage fee."

"Very funny," Sandy said. "W-was it you who pulled us out?"

"No," was the reply. "Bash pulled you out—then fainted next to you."

"A flair for the dramatic!" called Bashalli.

Sandy shook her blond head weakly. "I don’t understand. Tom—we couldn’t move! Something was pushing down on us! And then—unless it was part of a dream—someone in a ski mask came in—"

"I know," Tom interrupted her gently. "Your crony in mischief already told us most of it, San. When I came in, my repelatron was in pieces, smashed to bits. Whoever did it was already gone."

Bud approached and gave Sandy a warm squeeze and a kiss on the forehead. "But we owe something to the mad smasher, kid. According to Tom, it’s because he wrecked the machine that you weren’t held under when you blacked out. You floated free."

"I must send him a card of thanks," retorted the girl.

"Perhaps it would be better not to talk," her father urged. "Let’s have Chow bring us all some late supper, shall we?"

"Late supper!" Sandy exploded—which set off a fit of coughing. "My goodness, what time is it?"

Doc grinned. "About ten at night."

Clucking with concern, Chow provided a light, warm meal—for once a rather conservative one with a clear broth as its centerpiece. "If it ain’t one o’ you, it’s t’ other! You rambunctious kids’re gonna turn my hair gray!"

"Which one?" Bud teased.

Chow pointed. "This nice thick one on the right. The one on the other side done went gray in New Guinea!"

Bashalli’s bed was wheeled up next to Sandy’s, and the whole group of them were able to eat together. "But that hooded figure—in the ski mask!" Sandy said insistently. "Was he caught?"

Mr. Swift shook his head. "I’m afraid not. Harlan has had security guards searching every inch of the plant since Bashalli came to and told us what she had seen. But there was no sign of a stranger anywhere on the grounds."

"Nothing on the patrolscope, either," Tom added, referring to the plant’s sophisticated intruder-alert radar system.

Bud stared at his pal in dismay and groaned. "So the guy must’ve copped one of the radar-trappers—the amulets. That means we must have a subversive right on our own staff!"

"I know, flyboy," said Tom gravely. "The leak in the pressure tank sure looks less and less like an accident."

"The Moby Madmen!" Bashalli exclaimed. "The phantom whale is hiding here at Swift Enterprises somewhere!" Then she giggled. "Please do forget I said that. Too much oxygen, doctor."

Overruling her anxious protests, Sandy’s family joined Doc Simpson in urging her to lie back and rest. With a sigh, realizing she still felt shaky and weak, she obeyed. "All right—just so Bashi won’t get lonesome. But Tom—?"

"What, sis?"

"That machine of yours—what is it? What did it do to us?"

The young inventor grinned and gave her arm a pat. "It’s called a repelatron. What did it do? Purt near drowned you, that’s what!"

Sandy’s question was still on Bud’s mind the next day as he stopped by one of Tom’s personal labs, where he knew the young inventor was at work rebuilding his device. Entering, Bud saw that Tom was working side by side with the frail, wisp-haired head of the Enterprises nuclear chemistry section, Dr. Omicron Kupp.

Greeting them, Bud said, "If you feel like a three-minute mental break, Tom, how about telling me how this repelatron works? You’ve been kind of mysterious about it."

"I know," Tom said sheepishly. "But this is one of those inventions that’s pretty hard to explain, pal. If you want the basic version, it—"

Bud held up a hand. "No, no, none of the watered-down stuff, genius boy. Give me a chance to take it all in. I’m working hard to improve my scientific knowledge base. I’ve been reading those books you gave me—maybe not every page, but quite a few toward the beginning." He set himself down on a stool facing Tom and Dr. Kupp. "Okay. Ready. Go!"

Tom bit his lip and glanced at the elder scientist. "Doctor, you used to be a teacher. Why don’t you give my colleague Mr. Barclay here the three-minute course?"

"If you wish," said Kupp with a brusque nod. He squinted in Bud’s direction; it seemed he had failed to notice that the young pilot was in the room. "Tom’s repelatron, eh? It’s rather simple, in fact; basic physical theory. A first-year graduate student could easily master the fundamental concepts." He took up a position next to the white marking board that covered one entire wall of the laboratory, already half-filled with strings of numbers and symbols. "Obviously you’re familiar with the strong nuclear force, eh? Violates the inverse-square propagation law, acts as a shell holding the protons within the atomic nucleus, et cetera?"

"Right!" Bud said. "Strong nuclear force."

"Now: the repelatron exploits certain principles derived from studies of the Mount Goaba phenomenon, as well as the Jatczak gravitational anomaly manifest on the satellite Nestria…"

"The gravity cube in that cave," commented Bud. "I was there."

"Yes, of course." Kupp squinted about, as if he weren’t quite certain where the interruption had come from. "The standard interpretation originated in the eleventh footnote to the well-known journal article by Meinfeld and Yung, in which the term ‘entrained space-knots’ came to public prominence. We are speaking, then, of a stable field of interlaced twists in the local spacetime pseudo-plenum, extending through six virtual dimensions."

His mouth paused, and he looked vaguely in Bud’s direction. The young pilot smiled broadly and nodded.

"Now then," continued Dr. Kupp. "The conjecture of a relation between this phenomenon—denoted the spectron field by Tom Swift in recognition of its paradoxical, ghostlike character, as one might say—and the locus of the strong nuclear force appears well-founded, as I am sure you will agree. The spectron field may be visualized as a series of spherical shells, or layers—"

As Kupp turned his back to make a sketch on the whiteboard, a clanking and rattling in the corridor announced the presence of Chow Winkler and his snack cart. Making a sign to Tom, Bud stepped out the door and in a moment returned with Chow, guiding the rotund cook to a chair. Chow glanced back and forth but appeared willing to listen. Bud resumed his seat, turning slightly to take in Chow as well as Dr. Kupp.

Finishing his illustration, Kupp picked up where he had left off. "—layers which are comprised of tessellated discoidal segments, nodes, if you will, themselves having a spiral form and possessing a fractal character…" He looked up. Bud’s smile was now continuous. Chow sat wide-eyed and immobile. He appeared stunned. "That is to say, each component segment is itself composed of similar such segments, and so forth down to the Planck length. Being spiroforms of even-numbered dimensionality, the field constituents exhibit enantimorphic properties—handedness, you see, eh? Handedness. And thus, just as one’s right hand corresponds to the apparent left hand of one’s reflection, so it is that correspondence between facing field layers—that is, two fields propagating toward one another from distinct sources—requires that one field be laterally reversed by 180 degrees, as if through a half-rotation."

Bud’s smile, and Chow’s eyes, grew ever broader.

"The consequences, no doubt trivial, are of some practical interest despite their obviousness; to wit, the exchange of momentum between the paired fields by superposition of the nodal vectors, and in consequence between each field and its respective source, anchored to the nuclear shell and entangled therewith. Quite naturally a repulsion effect is evolved, expressed as opposed momenta with respect to the emitters—that is, the repelatron ‘generating antenna,’ as it were, and the array of atoms that constitutes its specific ‘target.’ I will anticipate a question by adding that the field structure is sensitive to nucleon array, as well as gross molar collocation. Hence the effect evolves only with respect to a particular atomic element in a well-defined mixture."

Dr. Kupp ceased to emit sounds, and after a time this was interpreted to signify the conclusion of the lecture. Tom suggested an early lunch, and the elderly scientist departed forthwith with the barest of nods to Bud and Chow. After the scientist had left Bud gently guided Chow back to his cart in the hall, patting him reassuringly on his broad back.

Bud returned, pushing the door shut and leaning against it, facing Tom. Bud’s smile was broad, deep, and granite-like. He slightly raised an eyebrow to his friend.

"The repelatron generates an invisible force that repels whatever it’s tuned to, passing right through everything else like a radio wave," Tom said with an understanding smile of his own. "I’ve got it working on certain mixtures of salt water. Sandy and Bash accidentally developed an adhering layer of the mixture by being in the pool, so the repulsion force affected them."

Bud nodded, turned, and exited in silence.

Tom waited until he was gone to get some affectionate laughter out of his system, then grabbed up the phone from the wall. He dialed Harlan Ames.

"It’s Tom, Harlan," he said. "Any clues yet on yesterday’s ski-mask saboteur?"

"None so far," the security boss admitted glumly. He continued: "Looks like an inside job, all right. I’ve had your lab locked up until we could go over it together. Care to meet me there?"

"Be there right away!" Tom promised.

Outside, taking the wheel of a midget electric nanocar, Tom sped past the large Enterprises airfield toward the isolated immersion dynamics laboratory building, where a guard had been posted. Harlan Ames was awaiting him outside the door. "Glad you’re okay, skipper," he greeted Tom. "I was afraid you’d be in mourning over the loss of your invention."

"Its rebirth is going along swiftly, Harlan. But we’ve got to identify the saboteur before anything else happens." Tom keyed open the door and they went inside.

The smashed repelatron was still lying on and about its framework tower, along with Tom’s scribbled calculations and hasty sketches strewn about a work-table nearby.

"Apparently the, er, assailant didn’t take anything," Ames remarked.

"This stuff wouldn’t do him much good," Tom replied. "What I’m worried about are the original plans."

Taking an electronic key from his pocket, Tom flicked a combination and beamed it at a steel wall cabinet. As the door slid open, he reached in and drew out a sheaf of blueprints.

"Still here!" the young inventor exclaimed in relief. "He either didn’t have the time to search out the blueprints—or maybe his only intention was to do damage."

Satisfied that the secret of Tom’s new invention was safe, Ames began to dust the laboratory for fingerprints. Unfortunately it soon became apparent that the intruder had worn gloves. Even the discarded length of pipe revealed nothing useful.

Suddenly the security chief heard a cry of excitement from the young inventor.

"Find something?" he inquired.

Tom held out a small wad of tangled threads that looked as if they might have been torn from a piece of fabric.

"Where did you find this?" Ames asked.

"Right here, dangling from the workbench where the two strips of molding corner together," Tom replied. "Probably got ripped off when he was rooting around among the loose papers. Wait a second. I’ll put it under a microscope!"

Going over to another table, Tom slipped the strands into place under the lens, then peered through the eyepiece and twirled the adjusting knob.

"Take a look," he said a moment later.

Both Harlan Ames and Tom examined the find with minute care. Apparently the fabric had been woven from dark blue and white cotton threads, with artificial fibers intertwined.

"Any idea where they might have come from?" Tom asked.

Ames frowned. "Yes. A pretty good one. This looks like the kind of material worn by the maintenance tech teams—anti-shock, anti-fire, chemical-resistant and easy to clean."

"Maintenance tech teams," repeated Tom thoughtfully. "Like Wes Beale’s crew, the guys who worked on the pressure-test tank!"

Beale was off for the day, but Tom and Ames were able to locate the three senior technicians by consulting the work-assignment schedules at the main building. Their names were Smith, Tonas, and Niffman. Their present team assignment was at Hangar E, where several experimental aircraft were berthed between test flights.

"I hate this," Tom confessed. "Wes Beale vouched for these guys—they’re his friends."

"I’m afraid that puts Wes under suspicion himself. Want me to haul ’em in for questioning?" Ames asked.

The young inventor shook his head thoughtfully. "Better not. If one of them’s guilty, he’ll bolt when he gets the message that you want to see him. Let’s head over to the hangar right now and catch them before they leave for lunch. I doubt the intruder will get too frisky in the face of both of us."

They drove over to Hangar E. As they walked in, their manner casual and unalarming, Doke Smith, a sandy-haired, husky young fellow of twenty-three, was tinkering with the afterburner of a sleek racing jet.

"Hi, Tom!" he greeted Tom cheerfully. Catching sight of Harlan Ames, he grinned. "What’re you doin’ here, Mr. Ames? Planning a little flyin’ spree? This one here’s a real beauty."

"That she is. Planes—I can’t keep away from ’em," Ames bantered, somewhat unconvincingly. "Say, where’d you get that rip in your work suit?"

"What rip?" Smith looked surprised as he noticed a tear along one leg, high up. "Oh, that. Search me. Caught it on an engine cowling, 1 guess."

The other two mechanics were busy in different parts of the hangar. Tom and Harlan quizzed each of the three men in turn, keeping their questions casual and friendly.

It was hard to believe that any of them might be guilty of the brutal acts that had endangered Tom and the girls. But the fact remained that none could provide a complete alibi for the previous day, at the critical time. The big hangar was crowded with planes and equipment, with the result that most of the time the men were not even in sight of each other.

Dropping the attempt to appear casual, Ames proceeded with a search of their lockers, which revealed no trace of a ski-mask or torn work togs. The first was not surprising, but Tom and Harlan hoped the intruder had not noticed the tearing of the fabric, as the piece had been left hanging. Perhaps he hadn’t noticed even yet.

Acting on a sudden hunch, Ames asked Milt Tonas if the planes now in the hangar had been there the previous afternoon and night.

"Far as I know," said Milt, a quiet-spoken. middle-aged man. "Are we suspected of something?"

Ames shook his head but ignored the question. "Were any planes taken out at all?"

"Don’t think so. But you can check the flight sheet over there on the wall."

With Tom helping, the security chief began checking every aircraft in the hangar. A few minutes later he stuck his head out the hatch of a newly designed cargo jet.

"Eureka!" Ames hissed, holding up a standard-issue work garment. A small hole had been ripped along a seam in the back, at exactly the right height! Ames quietly explained to Tom that the garment had been tucked out of sight under the engineer’s seat. Evidently its wearer had discovered the new rip and hidden the garb, fearful that it might identify him as the violent intruder.

"Now for the kill," whispered Ames, after examining the suit and passing it to Tom. He hurried back to check the posted test flight schedule, and returned a moment later, his face grim.

"This job’s due for a test flight at two P.M., and Reuben Niffman’s put himself down as flight engineer."

There was a tense, uneasy silence as the young inventor and the security chief looked at one another. Was Niffman their man? On the test flight, he could easily dispose of the telltale work suit by jettisoning it through the cargo hatch.

"Well, let’s get it over with," said Tom quietly. He had little relish for the prospect of having a once-trusted employee arrested.

Niffman looked up from his work as the two approached, regarding them with dull, sleepy eyes. He was a tall, slender man in his late twenties.

"Ever seen this before?" Ames asked him, holding up the garment.

The instant change in Niffman was startling! The technician’s face went ashen. His eyes seemed to glaze with fear as he stared at the telltale garment. Before anyone could stop him, he jerked a pistol from the deep pocket of his coveralls.

"Stop!" he screamed. "You’re not gonna take me alive! You maniacs! Back off or I’ll shoot!"

TOM and his companion fell back in horror as Niffman waved the pistol wildly. The trusted technician had suddenly morphed into an armed madman!

"Put that gun down!" Harlan Ames commanded. "Hurry! Drop it!’

"You can’t bluff me!" Niffman shrilled in a high-pitched voice. "This gun’s loaded, I tell you! Try anything and I’ll kill everyone in this hangar—Doke, Milt—everyone!"

Hearing his screams, Doke Smith and Milt Tonas dropped their work and came rushing to see what was happening. But at sight of the threatening weapon, they froze in their tracks.

"Now look, Rube," Tom spoke quietly. "You have nothing to be afraid of. We want to talk to you. We know something serious has happened; we just want to clear the air. Hand over the gun and let’s just talk."

Casually Tom took a step forwar