Tom Swift and the Electronic Hydrolung, II Appleton Victor [best books to read non fiction .txt] 📗

the job of adding sonar protection and sonar detection features to his electronic hydrolung. What an amazing fish man the wearer would be, Tom thought, if his project succeeded!

It would enable a skin diver to operate indefinitely under water at jet-propelled speed—invisible to enemy "eyes," yet be able to spy out any hostile undersea prowlers, including supposedly "undetectable" submarines!

Tom chuckled wryly as he mulled over the difficulties ahead. "Bud wasn't kidding when he said it would take a magician!"

Besides his mask, electronic breathing device, density-control unit, and ion drive, the wearer would now need at least three major additions—first, sonar-blinding equipment with electronic control; second, amplifying equipment to camouflage the wearer's noise under water; and, third, a portable quality analyzer sonar.

"Whew! The miniaturizing job alone will be a king-sized headache!" Tom said to himself. "I'd better start with a skin-diving suit made of that molded plastic Arv is turning out."

After having some of the Tomasite sheathing, with its embedding transducers, sent over from the plastics department, Tom cut out a suit from a pattern and welded the seams electronically. He had just finished wiring the control unit when Chow wheeled in a lunch cart.

"Got some deelicious steak-and-kidney pie today," the cook announced, setting it out.

"Swell," Tom said absent-mindedly.

Chow frowned but left without interrupting the young inventor. Twenty minutes later the cook poked his head into the laboratory again. Tom had not yet touched his lunch.

"Brand my vitaminnies, start eatin', boss!"

"Sure, Chow."

By this time, however, Tom had become so absorbed in the task of assembling some tiny monolithic blocks for the computer circuits of his analyzer, that the lunch remained untasted. When Chow returned a third time, Tom was startled by his bellow:

"Get your nose out o' that work, buckaroo, and eat!"

Realizing Tom's pie had cooled off, Chow had brought another serving, hot from the oven. Seeing the stern look on the Texan's face, Tom burst out laughing and obeyed meekly.

"I declare!" Chow chuckled. "One o' these days I'll have to force-feed you if you won't pay no mind to your own nourishment!"

"Sorry, old-timer." Tom smiled. "Sometimes I do get a bit wrapped up, I guess."

Hour after hour, Tom stayed glued to his workbench, sometimes busy with delicate electronic gear, sometimes lost in thought as he pondered a tricky problem in circuit design. It was long after dark when he drove home from the experimental station, yet he was back on the job in his laboratory early the next morning.

By lunchtime Tom had all the apparatus assembled. He was just trying on the plastic suit, with all its accompanying paraphernalia, when Chow made his usual appearance.

"Great sufferin' snakes!" the cook gasped. "You ain't goin' divin' in that getup, I hope! You look like a Christmas tree, boss!"

Tom nodded glumly. "Know something, Chow? That's just what I was thinking myself."

The young inventor's suit was loaded down with the various electronic units and festooned with wires. Even taking a few steps around the lab convinced Tom that the design was too unwieldy.

"I'd probably either get tangled in seaweed or sink from sheer weight," he muttered.

Changing back to his slacks and T shirt, Tom began eating abstractedly as Chow hovered around.

"If fishes could talk, I reckon you'd scare 'em half to death in that rig!" Chow said, trying to cheer Tom.

"Fish do talk," the young inventor said. "At least they make noises. Don't you remember that emergency fish-talk code we used when we were—"

Suddenly Tom paused, his mouth dropping open. "Chow! You've just solved my problem!" he exclaimed.

"I have?" Chow goggled at the young inventor.

"You sure have!" Tom bounced off his stool and began pacing about. "Now, take porpoises. They utter all sorts of sounds—grunts, squeals, jawclaps—and one particularly characteristic sound, like the grating of a rusty hinge."

Chow scratched his chin uncertainly. "Wal, what about it?"

"Suppose I used that rusty-hinge noise to mask the diver's noise." Tom turned and stabbed the air with his finger. "I could also use that same sound output as the search pulse for my quality analyzer sonar!"

In this way, Tom explained, he could eliminate part of his bulky equipment and do an even better job of making the diver "invisible."

Bubbling with enthusiasm, Tom decided to buy a live porpoise at once and make an exact recording of its sounds. As soon as he had finished lunch, he put in a number of calls to suppliers of marine specimens. But none could provide a porpoise on short notice.

"Guess I'll have to catch one myself!" Tom told Chow.

He drove out to the airfield and took off in a Whirling Duck for Fearing Island. At the base, both Mel Flagler and Zimby Cox were eager to accompany the young inventor when he told them about the trip he had in mind.

Tom chose the Sea Hound as the fastest and best suited craft for his purpose. With Mel's and Zimby's help, he quickly rigged a plastic "tank" in the stern cabin. Minutes later, the seacopter zoomed skyward, heading for the Florida Keys.

The flight was a short one at transonic speed. Tom chose a sparkling stretch of open water, a mile or so offshore from a palm-green islet. Zimby agreed to stay aboard and tend ship while Tom and Mel went over the side in hydrolungs.

The two glided about in the translucent blue depths, keeping in close range of each other. The sea was alive with shimmering fish of every hue, darting among the coral. Suddenly, as Tom veered around to rejoin Mel, his eyes widened in horror.

A vicious-looking hammerhead shark was zeroing in, directly behind his friend!

"Look out!" Tom yelled over his microphone.

CHAPTER XVIII

SMILEY THE SEA COW

Mel turned in the nick of time. The monster shark was bearing down on him like an undersea express train. Overcoming a moment of panic, Mel gunned his ion drive to dodge the attack.

As Tom watched in agonized suspense, he saw the shark's jaws open and shut in a lightning snap at Mel's outstretched arm. Its razor-sharp teeth missed their target by inches!

Mel's gasp of relief was audible over Tom's earphones. "Let's get out of here!" he cried, arrowing away from the man-killer.

Suddenly Tom realized the full extent of their peril. A long, sweeping coral reef, which extended above water, lay between them and the Sea Hound. Unless they could round the reef in time, the shark had them trapped!

"Quick! This way!" Tom exclaimed.

The shark was moving at blinding speed. As if sensing the boys' plan of escape, it launched itself in a wide curving sweep to cut them off.

"We can't make it!" Tom gasped. "We'll have to fight!"

Both swimmers were armed with skin diver's knives as a precaution. The two maneuvered to meet the killer's onslaught.

This time its broad nightmarish head was aiming straight at Tom. He jetted off to the right, but the monster veered instantly. Its lashing tail gave Mel a stunning blow.

As the shark's jaws gaped for a bite, Tom zoomed underneath the man-eater and slashed its belly with his knife.

The shark, maddened, thrashed the water in a frenzy. Tom moved like lightning to dodge a deadly blow from its bony tail. Again and again they felt the horrifying brush of the killer's fins or armor-tough hide. By this time, Mel had revived. Repeatedly the two boys dived to jab and slash at the shark's soft underbelly.

Both were nearly exhausted when the monster at last went limp and floated slowly up toward the surface. Pale with shock and fright, Tom and Mel jetted back to the Sea Hound.

Zimby Cox was startled by their faces when they clambered aboard and ripped off their masks. "What happened to you two?"

Tom told him. "Good night!" Zimby cried out.

After resting, Tom and Mel dived in again. This time luck was with them. In less than twenty minutes they sighted a small porpoise.

"Think we can lure it back toward the Sea Hound?" Mel queried.

"We'll try," Tom replied.

The creature with the bottle-shaped snout was as friendly and playful as most of its fellow dolphins. Too playful, Tom concluded, after vainly trying to tease it into chasing them. Instead of following, it would "tag" Tom or Mel quickly, then swim away, evidently expecting to be chased in turn!

"I give up!" Mel snorted in disgust.

Tom grinned and bobbed to the surface. He waved his hand several times in a prearranged signal. Zimby at last spotted him and brought the Sea Hound to the scene.

Raising his mask, Tom called, "Let's have the net!"

Zimby lowered a nylon net and some pieces of fish to the two swimmers as they came alongside. With the food as bait they tried to lure the porpoise to the seacopter. But just as they thought they had it, the monster would scoot off.

"It's just laughing at us!" Mel fumed.

At last, after winning its confidence with several bits of fish, the boys succeeded in snaring the porpoise. Tom clambered onto the Sea Hound's deck and helped Zimby haul their catch aboard. "Quacking" reproachfully, it was lowered through the hatch and placed in the tank, which was then pumped full of salt water.

As soon as the Sea Hound arrived at Fearing, Tom phoned Chow Winkler at Enterprises and asked him to fly out to the base.

"Pardner, how'd you like to ride herd on this critter and gentle it down for me?" Tom asked, when he showed Chow the porpoise.

It had been transferred to a huge, glass-paneled tank which had been set up just outside Tom's Fearing Island laboratory during his flight to the Florida Keys.

"Reckon I kin try makin' friends with it," Chow declared.

The porpoise stared morosely at Chow. The kindly old Texan's heart was touched by the odd creature. To his delight, it soon responded to his friendly overtures and quickly recovered its good nature. By the next morning the porpoise was playing catch with Chow, or else swimming over to have its back scratched. The cook named it Smiley.

"She's kind of a sea cow," he told Tom, "and you got to talk to my Smiley like any cow!" Tom grinned and refrained from explaining to Chow that a real "sea cow" was a walrus.

Meanwhile, the young inventor was busy with his own experiments. By means of a microphone placed in the tank, he made exact recordings of Smiley's "talk." Using Mel Flagler as a subject, Tom also tape-recorded the sound of a skin diver propelled through the water by ion drive.

The next step was to compare the sound pattern of the tapes. Tom filtered out the difference in the two sounds with the correlation calculator unit of one of his quality analyzer sonars.

"Uh-huh. So you got the difference betwixt Smiley's talk an' the noise Mel made," muttered Chow as he watched the jagged lines of light flashing on the pulse-check oscilloscope. "Now what're you fixin' to do with it?"

"This will be fed into the diver's sonar along with his own noise output," Tom said, "to make him sound like a porpoise."

Chow howled. "That I've got to hear!"

The young inventor worked feverishly throughout the day and into the next, perfecting his new "porpoise sonar." Using microelectronic components, he was able to reduce all the units to amazingly small size.

Next, Tom began tailoring himself a completely new skin-diving suit. Mask, ion-drive jet, and the various hydrolung units were molded into the plastic, with no loose wires or tubes showing.

Monday morning he was ready to try the outfit. The sonarscope with its tiny viewing screen was strapped to his left forearm. Another small unit was fastened to the inside of his wrist, with four plungers in finger-tip reach.

"What in tarnation's that?" Chow asked.

"Simplified controls," Tom explained. "One's for breathing adjustment, one's for the density unit, one is my ion-drive 'throttle,' and this last is for the sonar pulse—which will duplicate the porpoise sound."

The suit worked perfectly in a tank test. Chow was amazed as he listened to Tom gliding about, via an underwater microphone.

"If that don't beat all!" he declared. "Can't tell the difference 'twixt you an' Smiley!"

As Tom emerged from the tank, the portly cook rolled up