"You bet it's a date, and don't you forget it!" Sandy warned. "Phyl and I are going right over to Dorman's Department Store and pick out some cute outfits for the dance!"

Tom and Bud chuckled over the success of their scheme as they drove back to Enterprises. Later that afternoon a telephone call interrupted Tom as he worked in his lab on a sonic-communications system for the hydrolung apparatus.

"This is Lester Morris," said the voice at the other end of the line.

The name did not register with Tom at first until his caller added, "I hear you're planning a square dance Tuesday night at the yacht club."

Suddenly Tom remembered. Lester Morris was a popular dance orchestra leader in and around Shopton. He was also much in demand as a square-dance caller and fiddler.

"That's right," Tom said with a chuckle. "News must travel fast. We just phoned invitations to our friends."

Morris asked if musicians had been hired for the evening. When Tom said No, his caller volunteered for the job, offering to provide a small combo of country-style players. His asking price sounded like a bargain rate, and Tom, knowing Morris's reputation, was only too glad to engage him.

"Lucky break, his calling," the young inventor thought as he hung up.

Bud was delighted to hear of the arrangement when he came into the laboratory a while later. The boys talked over their dance plans for a few moments, then Bud asked:

"How's our underwater talkie system coming?"

Tom scratched his jaw thoughtfully. "A bit tricky but not too difficult," he replied. "It's mostly a job of adapting the sonarphone arrangement from our Fat Man suits--in miniature."

A tiny mike, Tom explained, would be installed on the inside of each face mask, with its output feeding to a sonar transducer on the exterior. The receiving transducers would feed from amplifiers to earphones. The hookup would be powered by the solar battery in the hydrolung power unit, by connecting wires through the breathing tube.

"That's neat, Tom," Bud said. "Need any help?"

"You can mold us a pair of new face masks--big enough to cover the earphones," Tom suggested. He handed Bud a penciled sketch from the workbench, adding, "Then drill the holes for the mikes and earphones--the dimensions are there on the drawing. But watch it so you don't crack the plastic."

[Ill.u.s.tration: _Chow was wild-eyed with panic!_]

While Bud complied, Tom began a.s.sembling the tiny electronic parts. In two hours the gear was ready for testing.

Tom wiped his perspiring forehead and gave Bud a grin of satisfaction.

"Go get your swim trunks, fly boy. Let's give it a tryout in the tank."

"Swell idea! Be back in a jiff!"

After a quick change, the boys strapped on the new hydrolung equipment.

Before adjusting his face mask, Tom mentioned that he had inserted scrambling circuits into the communicators to foil any enemy eavesdroppers.

"If they do pick up anything, it'll sound like chop suey," Tom ended with a chuckle.

The boys submerged in the test tank and proceeded to give the new underwater communication system a thorough check-out. It worked perfectly. Ten minutes later Tom and Bud clambered out again, dripping wet but well satisfied.

They had just peeled off their masks when Chow came charging into the lab, with a crowd of workmen and technicians at his heels. The cook was wild-eyed with panic.

"What's wrong, Chow?" Tom asked in alarm.

CHAPTER IX

A MAGNETIC KIDNAPING

"The s.p.a.ce people or some enemy's invadin' us!" Chow shouted. "Take a squint through your telescope, boss! Brand my bazooka, they may be landin' any second!"

More people came streaming in, attracted by the chef's cries and gesticulations. Some were bewildered, a few frightened. Others were laughing, thinking the whole thing a joke. The scene was rapidly taking on the proportions of a riot!

"Whoa! Slow down, Chow!" Tom ordered, trying to make himself heard above the din.

"It--it's the truth, boss!" Chow stammered, mopping his brow with a huge red bandanna. "Why, sufferin' rattlesnakes, didn't I hear 'em spoutin'

their s.p.a.ce lingo with my own ears?"

"You heard _what_?" Bud said.

"Spoutin' s.p.a.ce talk!" the cook repeated. "It come right over the loud-speaker in the galley! They was chitter-chatterin' plottin' to blow us all to smithereens!"

"That's a fact! We heard it, too!" one of the workmen chimed in.

Tom and Bud looked at each other blankly. Then suddenly Tom's eyes kindled with a dawning suspicion. Whirling around, he rushed over to inspect the public-address outlet on the wall.

Meanwhile, Mr. Swift had just driven in through the main gate of Enterprises. "What's going on?" he asked the guard at the gate, noting the excited hubbub around Tom's laboratory.

"Don't rightly know, sir," the guard replied. "I was wondering myself. I know it sounds crazy, but I thought I heard someone yelling there was going to be a s.p.a.ce attack."

Mr. Swift's eyebrows lifted in amazement. Without further discussion, he stepped on the accelerator and sped off along the paved drive. Seconds later, his car braked to a stop near Tom Jr.'s private laboratory. The scientist jumped out and made his way through the milling crowd.

"What's going on?" Mr. Swift stared in astonishment at Tom and Bud, who were both doubled up with laughter.

"A scrambled radio alert, Dad," Tom gasped between chuckles. "Chow thought some Martian monsters were invading us, and sort of pushed the panic b.u.t.ton."

The Texan blushed as Tom explained what had happened. Realizing Chow's embarra.s.sment, Tom tried to make his mistake sound understandable.

Apparently the power line to the ion-drive control board had somehow picked up the boys' scrambled conversation underwater. The signal had been transferred by inductance in the wall wiring and amplified over the public-address system.

"Our wall mike was on," Tom added, "and it probably picked up some of the sound waves from the tank. Anyhow," he concluded, slapping the cook affectionately on the back, "I'm sure glad we have a wide-awake hombre like Chow in the outfit. It wouldn't be the first time he's saved our necks!"

Chow perked up, and the employees, rea.s.sured, returned to their jobs.

"I have some news of my own," Mr. Swift announced with a smile as the room cleared. "But I'm afraid it'll sound pretty tame compared to a s.p.a.ce attack."

"Let's hear it, Dad," Tom said eagerly.

"I've been conducting some experiments with those s.p.a.ce plants," the elder scientist said. "It looks as though they may prove to be a valuable nutritional source."

The plants, Mr. Swift went on, showed promise of producing enormous amounts of protein quickly and cheaply--enough to increase the world's food supply by a sizable margin. Moreover, he had isolated a vitamin in this protein not found in any of man's present foods.

"Doc Simpson has been working with me," Mr. Swift concluded. "He has been doing some experiments of his own with a vitamin extract from the s.p.a.ce plants. He thinks it may prove highly beneficial to human beings."