yet, Harlan," he said. "But I'll alert the guards at the plant
to be on the lookout for an unauthorized visitor."

"Thanks, Phil." Ames hung up and turned away from the telephone with an
embarrassed 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. retired
with 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're
ready to co-operate with any moves you care to make. I take it you're
prepared to carry out a search on your own, Tom?"

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

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

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

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

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

The next morning he eagerly tackled 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 pl