Tom Swift and the Mystery Comet (5 page)

Tom contacted his father at Enterprises via the shed’s videophone setup, the Enterprises private TV communications network, relayed worldwide by the space outpost and other satellites. "I just called down, Dad—still keeping it calm, but there’s something in Mr. Hollifeld’s voice..."

"The possibilities are frightful, Son, whether Hollifeld wants to admit it or not."

"I know, Dad. I guess your instincts were on the money. I’m heading down now to see for myself, but—it might be smart to ready our planned evacuation procedure."

"I’ll begin immediately."

Hearts thudding with suspense and dread, Tom and Bud crossed the short gangway to one of several small, square platforms equipped with a repelatron radiator, a gold-hued sphere of metal that halfway penetrated the deck. By thrusting back the seawater to produce a controllable air bubble around the structure, the undersea elevator, linked to vertical guide cables, allowed passengers to safely descend to the facility below.

With a wave to Dixon Wade in the monitor shed, Tom took hold of the bubblevator controls, atop a pedestal adjoining the surrounding rails. A circular depression leapt into being under the transport, flattening the waves with repulsion force. "Going down," murmured the young inventor, easing back on the master lever. Instantly the partial bubble diminished and the platform began to descend in response to the minimization of its buoyancy. The sides of the air-filled sphere rose up and closed in around them, meeting over their heads as they entered the water smoothly.

"At least
this
jalopy’s working all right," said Bud—a bit more loudly than necessary.

Tom nodded as he craned his neck, looking downward past the edge of the platform with nervous urgency. "Can’t see anything yet. But that’s normal in midocean seawater; Helium City’s pretty far down."

The last of the light from the surface had faded away completely. "I won’t switch on the lamps," Tom told his fellow hydronaut. Bud understood that Tom wanted to be able to catch the first gleams from below. It struck the young pilot that his pal seemed unusually jittery.
Jetz, maybe this is worse than I thought,
he wondered.

Moments later a slight twitch passed through the deck. Before the youths had time to wonder, another came, much more powerful. The bubblevator began to waver and rock back and forth, swinging on its guide cables! "Good night, what’s up with
this
?" Bud gulped. "I’m gonna get
subsea
-sick!"

"Problem with the buoyancy!" Tom grated, tightly grasping the guardrail.

"Th-the bubble isn’t about to go bad on us—
is
it?"

"No deformation," replied Tom. He looked up overhead. "But you can see what’s happening." The air bubble was wiggling and twisting on all sides, like an unsteady soap bubble in a fluttering breeze. Tom reached for the controls, preparing to expand the bubble and head back up at top speed—but before he could take action the bubblevator sphere suddenly became rigid again.

"
Whew
!" Bud breathed. "Guess she got over it."

"Got over
what
?" Tom demanded with a deep frown. "There’s no problem with the telespectrometers. Nothing unusual in the seawater. The power from the solar batteries held steady all through."

"What about the currents? You know, pal—one of those deep-water jetstreams."

"The automatic scanners don’t show a thing. Just a few fish."

"Bet we spooked ’em!" chuckled Bud nervously.

There was no further turbulence, and presently Tom announced, relief in his voice, that he could make out a hazy glow down beneath. "At least the lights are still on."

"Yeah. But if the lights are on and nobody’s home, I’m leaving!" The gibe fell flat.

The light changed from sea-green to yellow to white as they came even with the transparent hemisphere of the hydrodome. "Plenty of people walking around," observed Bud. "I just hope they’re
ours
, Skipper."

"I see Mr. Hollifeld," Tom declared. "And there’s Nina Kimberley."

Bud grinned "Kinda stands out—a mermaid among mermen!"

At last the bubblevator touched down on its concrete pad and was automatically locked in place. Tom increased the small bubble until it overlapped the adjacent section of the huge hydrodome airspace, allowing them to walk directly into Helium City.

All around the circular floor of the installation—seafloor of gravel, mud, and sand, dried by infrared lamps—workers rose to their feet from the pipes and machinery they were attending to and waved a greeting at Tom and Bud, which they returned. Wilt Hollifeld, the chief of operations, rushed forward to shake hands. "Glad you’re here! We don’t know what to make of this health problem," he told Tom. "Started just a while ago, all of a sudden. Doesn’t last long, but when you can’t figure the cause..." Despite his hearty tone, worry was etched on his face.

"Can you think of
anything
that might have set it off, Mr. Hollifeld? Anything unusual?"

The facility chief shook his head. "Not a thing. Seems it’s over, though. Most everyone’s been released by Dr. Praeger."

"That’s good to hear!" But the news gave the young inventor only a half dose of cheer. "Still, we’d better figure out what’s going on fast. Bud and I encountered some difficulties on the way down." He described the unexplained behavior of the bubblevator system.

"We don’t like coincidences," Bud noted.

They entered the main building, which included the dorm, mess hall, and the small infirmary and sick bay. Tom was introduced to Dr. Praeger, a petite young woman who had interned with Dr. Carman, the chief physician on Fearing Island. "The medical situation seems to have abated, Tom," she reported. "All but a couple of the men are back at work."

"May I speak to those two men, doctor?"

The two workers, introduced as Mike and Orlando, were resting on cots in the sick bay section. They appeared somewhat pale but shook hands vigorously as Tom and Bud approached them. "We don’t know any more about it than anybody else," Mike shrugged. "Just got kinda wheezy."

"I got wobbly on my feet, Mr. Swift," added Orlando. "My lungs started gulpin’ air a little, so I figgered I’d better come see the doc. Feel fine now. Er—will this look bad on my work record, ya think?"

Tom grinned. "Not at all. Actually, safety depends on you fellows checking in whenever you’re not in top shape."

"The Swifts are marshmallows, man," gibed Bud, who was employed by Enterprises as pilot. "You can get away with
anything
!"

As Hollifeld and two of the foremen joined the little group, Tom asked: "How many of the workers reported feeling woozy?"

"Altogether, twenty-two," responded Cara Praeger. "That’s most of the work force. But except for these two big bruisers, everyone was cleared for duty within a couple hours or so. The symptoms were all similar, none of them medically acute."

"And you don’t know the cause?"

Hollifeld replied for Dr. Praeger. "Nothing’s been identified. No sign of virus, fungus, or bacteria. Body temperatures stayed normal."

"There was a slight increase in heart rate and blood pressure, which is normal during stress," Praeger noted. "Mostly it was just a passing spell of wooziness, kind of a choking feeling."

"I see. Where were the victims when this thing struck them?"

"No one place," said one of the foremen, "no one job. They were just out workin’ here and there all around the dome, like per usual. It’s what we’re paid for."

Tom rubbed his chin. "I don’t have any kind of medical training, I know. The way it comes across to a layman, it seems like
anoxia
—their lungs just weren’t getting enough oxygen."

"It kinda felt like that," agreed Mike.

"But we checked out the air and pressure immediately," Hollifeld pointed out. "Checked the instruments themselves as well. Besides, they would have sounded an alarm automatically."

"I know," said Tom, puzzled. "And it would have affected everyone. Okay, let’s use the scientific method—one thing I
do
know something about! The people who came down with the symptoms seem to have had nothing in particular in common. What about the
rest
of the work force, the ones who
didn’t
get sick?"

The hydrodome employees exchanged glances. "The others?" repeated Dr. Praeger. "You mean like me and Wilt here?"

"Joe here came down with it out by the pumping rig, so he doesn’t count," said one of the foremen. "Me, I didn’t get it, but I wasn’t doing anything special."

"Well, for example, were the unaffected people all indoors during the critical time period?" Tom suggested.

"I guess most were," conceded Hollifeld. "But not all of ’em. I was outside all morning, and nothing happened to me."

"You say...
most
of the unaffected were indoors," repeated Tom, looking downward in the depths of thought. Suddenly his face brightened. "Your knees!"

Hollifeld boggled. "Huh? Our
knees
? What about them?"

Bud suddenly grinned. "Hey, I think I get it. Look at Orlando here, and Mike—and Joe too. Look at the knees on their work uniforms!"

The three gawked at their own knees and the knees of the others, puzzled. "What’re we supposed to be seeing?" grumbled Joe Eyling.

"Your pant knees are grimy, dirty," Tom declared.

"Yeah? So? Even with the tron running it gets muddy out there."

"But
my
knees are clean," murmured Mr. Hollifeld. "Are you saying something is spreading by way of mud or dirt?"

"No," stated Tom. "I’m just telling you what I noticed first—and
then
my ‘scientific intuitions’ led me further. I’m supposed to have an overactive imagination, so I’m told!

"I’m guessing that those who weren’t affected are mostly supervisors or technical support people—you could call yourself that, Doctor—who didn’t have occasion to kneel down or crouch low to the ground during the last day or so. You spend most of the time working indoors, in the building."

"Sure—not exactly white-glove work, but our
knees
stay clean, usually. Most of the outside work crew’s almost always getting down and dirty for one reason or another," agreed Hollifeld. "We others all go out into the open space now and then, naturally, but we don’t usually have to kneel down right on the ground."

"But..." Dr. Praeger was bewildered. "What’s coming from the ground that could cause such symptoms?"

Tom said, "Not
from
the ground—
near
the ground! I’m thinking that heavy trace gases of some kind might have leaked into the dome, gases that drift around but stay concentrated
low to the ground
. They could be odorless and colorless, but anyone who happens to breathe them in while kneeling or crouching might feel breathless from reduced oxygen."

"I guess—it’s worth checking out," Hollifeld admitted. "The intakes for the monitoring sensors are mostly up on the beams, now that I think about it. They’re built into the big overhead pylons that hold the lamps and the air circulation vents. At that height the monitors might not have sucked in enough of the gases to cross the alarm threshold."

Picking up some hand-held analysis instruments, Tom led the others outside and bent low. "That’s it!" he cried jubilantly. "Argon, radon, nitrous oxides, complex hydrocarbons..."

"A real city with real smog!" Bud joked.

"It stands to reason," commented Hollifeld. "This whole area is stocked with all manner of gaseous compounds, not just helium."

"Right now the traces in the air are almost nil," reported Tom. "The scrubbers have filtered most of the stuff out."

"If only traces remain, the leakage must have diminished or stopped," noted Hollifeld. "Some kind of brief or intermittent problem. But Tom—what if it happens again, worse? For all we know it could signal that something big’s going on down here, maybe something that could wipe us out!"

"YOU’RE right," stated Tom Swift quietly. "We have to take it seriously."

"Got a theory, pal?" Bud inquired, thinking:
Like I have to ask!

"Maybe. Let’s go back inside. I want to look through the recorded monitor data in detail."

The youth spent an hour poring over the output from the various sensor devices, examining all readings made over the preceding two days. At last he waved Hollifeld over. "I guess I have a correlation. I don’t know just yet how well it works as a
cause
, though."

"What did you find that I missed?" the man asked in a defensive tone.

"Nothing anyone could have expected you to find, sir," replied Tom soothingly. "It was the ‘clue of the knees’ that gave us the real timeframe of the incident. Since we’re dealing with drifting and settling gases, whatever happened initially must have occurred quite some time
before
the symptoms became noticeable. You wouldn’t have been looking for that."

"Yes. Didn’t think to," conceded Hollifeld. "But what could it have been, Tom?"

"Something big enough to have travelled
22,300 miles
to do its dirty work!"

Bud’s eyes widened—as he swelled with pride in his best friend’s cool acuity. "Jetz! The repelatron stutter up on the space outpost!"

Tom described the strange, brief phenomenon. "But how could something like that create a flow of gases?" demanded the operations chief skeptically. "Wouldn’t our sensors have detected a repelatron problem like that?"

"They did! It’s just that you were looking in the wrong timeframe."

Dr. Praeger had approached and was listening intently. "Even if that space event had something to do with the breathing problems—what about the interference you two ran into?
That
happened within the hour, long after the other phenomenon."

"Let me explain," Tom began. "Our usual monitor instruments don’t measure the spacewave repulsion field directly, but only its effects on the materials selected and its backpressure on the repelatron itself. In the outpost we were all in a position to immediately feel the effects of a fluctuation—the repelatron force was what was holding us down. That’s not the case here in the hydrodome. Small-scale oscillations over such a big surface as the dome wouldn’t be very noticeable to the eye, not if it didn’t last long. But," he continued, "that’s not to say it wouldn’t have a significant effect. It would still hold back the seawater, but I can understand how small ‘wigglings’ at the margins of the air-water interface, the ‘bubble,’ might cause minute nodal points of field decoherence—making the bubble wall porous to certain loose molecules."