Tom Swift and the Electronic Hydrolung

by II Victor Appleton

  CHAPTER XVII

  A MISSING AMULET

  Bud's curiosity was instantly aroused. "Don't tell me you have a newtrick up your nautical sleeve to fox the Brungarians?"

  Tom grinned. "That's the general idea. I hope to give hydrolung diversthe same protection that your jetmarine has."

  "You mean make them invisible to sonar?"

  "Yes," Tom replied, "and also give them personal spy gear to probe thewaters around them and spot an 'undetectable' enemy."

  Bud whistled. "Do that, and I'll say you're _really_ a magician,skipper!"

  Tom himself transferred the analyzer from the _Sea Hound_ to Bud'sjetmarine. On a chance that it might become necessary to operate atgreater depths--either in searching for the lost missile or in shadowingthe enemy--Tom also assigned Arv Hanson the job of rigging the _SeaHound_ and another seacopter with his new inventions.

  Four crewmen volunteered for the cruise. When the jetmarine was ready,Tom and Bud exchanged tight handshakes.

  "Good luck!"

  "Thanks, Tom."

  The young inventor waved as Bud disappeared down the hatch. As soon asthe craft had submerged, Tom went back to Shopton. That evening theSwifts were enjoying a quiet dinner at home when a loud, growling buzzshattered their mealtime conversation.

  "Oh!" Sandy gasped. "The burglar alarm!"

  The Swifts' house and grounds were protected by a secret magnetic field.Any intruder breaking the barrier touched off the automatic alarmsystem. To avoid the buzzing, the family and their close friends worewrist watches containing tiny neutralizer coils.

  "I'll see who it is," Tom said, and hurried to the door, feeling atwinge of apprehension.

  _Was this a new attempt by Brungarian agents?_

  He switched on the porch light and peered out cautiously through theone-way glass pane in the door. A slim, hatless figure in a dark suitwas just coming up the steps. Tom gave a smile of relief.

  It was Harlan Ames!

  "Hi, Harlan!" Tom opened the door before Ames had a chance to ring thedoorbell. "We heard you coming!"

  The security chief was startled when he realized he had activated thealarm system.

  "That's strange," he said uneasily. "Tom, I wonder if--"

  He broke off to dart a quick glance at his wrist. Then his face relaxedinto a look of chagrin.

  "Great! I forgot my wrist watch!" he murmured. "Haven't visited yourhouse in so long I neglected to wear it."

  The other Swifts smiled in amused relief, and Mrs. Swift invited him tojoin them for dessert. Ames, however, declined politely.

  "Thank you, but I just finished dinner myself," he explained. "I droppedby to--"

  Once again Ames's voice trailed off in midsentence, as he reached intothe side pocket of his coat.

  "My amulet!" he gasped. "It's gone!"

  "Are you sure?" Tom said with quick concern.

  Ames nodded as he frantically tried all his other pockets. Theelectronic amulet to which he referred had been issued to allEnterprises personnel and family visitors who used the private gate. Theamulets were contained in slender bracelets and were designed to trapradar impulses. This prevented them from showing up as blips on thegiant detector radarscope mounted on the main building. The purpose ofthe scope was to reveal unauthorized visitors or spies.

  "My bracelet broke this afternoon," Ames said. "I slipped it into mypocket to have it repaired. But it's not there now!"

  Tom grabbed a flashlight and dashed outside for a hasty check of thewalk. Ames followed, to look inside his black sedan. But the amulet didnot come to light.

  "Did you go home after you left the plant today?" Tom asked.

  Ames shook his head worriedly. "No, I stopped at a restaurant. Mind if Iuse your phone?"

  "Go ahead."

  The security chief called Enterprises and asked his assistant, PhilRadnor, who was on night duty, to make a thorough search. While awaitingthe results, Ames also called the restaurant, but learned that no suchitem had been turned in.

  Half an hour later Radnor called back to report no luck. "The amulet mayshow up yet, Harlan," he said. "But I'll alert the guards at the plantto be on the lookout for an unauthorized visitor."

  "Thanks, Phil." Ames hung up and turned away from the telephone with anembarrassed look. "Fine example I'm setting as head of plant security,"he murmured. "Let's hope the amulet wasn't stolen."

  Excusing themselves from Mrs. Swift and Sandy, Tom Sr. and Jr. retiredwith Ames to Mr. Swift's study to discuss the news he had brought.

  "I had a late call from Admiral Walter this evening," Ames explained."The Navy's getting pretty desperate over that lost missile. They'reready to co-operate with any moves you care to make. I take it you'reprepared to carry out a search on your own, Tom?"

  The young inventor nodded. "Yes, as soon as I've perfected all the gearI'll need--which won't be long, I hope."

  Ames added, unhappily, that certain papers and news commentators hadbeen making snide remarks about the Swifts' failure to match theBrungarians' submarine achievement.

  "I think Tom has that situation pretty well in hand," Mr. Swift remarkedwith a smile.

  Tom gave Ames a full report on his own apparatus for rendering asubmarine invisible to underwater detection. Ames grinned at the news.The grin grew even wider as he heard of the successful test of thequality analyzer sonar.

  "Bud Barclay's on his way to the South Atlantic right now with a fullyequipped jetmarine," Tom ended.

  The next morning he eagerly tackled the job of adding sonar protectionand sonar detection features to his electronic hydrolung. What anamazing fish man the wearer would be, Tom thought, if his projectsucceeded!

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

  Tom chuckled wryly as he mulled over the difficulties ahead. "Bud wasn'tkidding when he said it would take a magician!"

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

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

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

  "Got some _dee_licious 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. Twentyminutes later the cook poked his head into the laboratory again. Tom hadnot yet touched his lunch.

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

  "Sure, Chow."

  By this time, however, Tom had become so absorbed in the task ofassembling some tiny monolithic blocks for the computer circuits of hisanalyzer, that the lunch remained untasted. When Chow returned a thirdtime, 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 burstout laughing and obeyed meekly.

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

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

  Hour after hour, Tom stayed glued to his workbench, sometimes busy withdelicate electronic gear, sometimes lost in thought as he pondered atricky problem in circuit design. It was long after dark when he d
rovehome from the experimental station, yet he was back on the job in hislaboratory early the next morning.

  By lunchtime Tom had all the apparatus assembled. He was just trying onthe plastic suit, with all its accompanying paraphernalia, when Chowmade 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 wasthinking myself."

  The young inventor's suit was loaded down with the various electronicunits and festooned with wires. Even taking a few steps around the labconvinced 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 abstractedlyas Chow hovered around.

  "If fishes could talk, I reckon you'd scare 'em half to death in thatrig!" 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 justsolved 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 ofa rusty hinge."

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

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

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

  Bubbling with enthusiasm, Tom decided to buy a live porpoise at once andmake 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 nonecould 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 FearingIsland. At the base, both Mel Flagler and Zimby Cox were eager toaccompany the young inventor when he told them about the trip he had inmind.

  Tom chose the _Sea Hound_ as the fastest and best suited craft for hispurpose. With Mel's and Zimby's help, he quickly rigged a plastic "tank"in the stern cabin. Minutes later, the seacopter zoomed skyward, headingfor the Florida Keys.

  The flight was a short one at transonic speed. Tom chose a sparklingstretch 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 overthe side in hydrolungs.

  The two glided about in the translucent blue depths, keeping in closerange of each other. The sea was alive with shimmering fish of everyhue, darting among the coral. Suddenly, as Tom veered around to rejoinMel, his eyes widened in horror.

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

  "Look out!" Tom yelled over his microphone.