ome
sort of ray that caused the set to explode?" Bud demanded.

Tom's face showed clearly that Bud had pinpointed the suspicion in the
young inventor's mind. "Could be."

Bud was worried by this latest development. "Skipper, suppose I hop up
to the space wheel and talk it over with your dad. He may be able to
help us detect any enemy moves."

"Good idea, pal," Tom agreed. "The sooner the better, I'd say."

The boys exchanged a quick handshake and affectionate shoulder slaps.
Then Bud hurried out to one of the Enterprises hangars to ready a
helijet for the flight to Fearing Island. This was the Swifts' rocket
base, just off the Atlantic coast. From there, Bud would board one of
the regular cargo shuttle rockets operating between the space station
and Fearing.

Tom, meanwhile, plunged back to work on his shock-wave deflector.

At ten the next morning he called in Hank Sterling and showed him a set
of completed drawings.

"Hank, you did a fast job on the container for the brain," Tom began
apologetically, "but you'll really have to burn out a bearing on this
one!"

Hank grinned. "I'm geared to action. Say, what do we call it, anyhow?"
he asked.

Tom grinned. "Chow told me last night this gadget looked like a fireplug
under a rose trellis and I ought to call it Fireplug Rose! But I've
given it a more dignified name--the Quakelizor, which stands for an
underground quake wave deflector."

Briefly, Tom explained the various parts of his latest invention, which
consisted of a hydrant-sized cylinder to be inserted into the ground,
with magnetic coils near the top. A smaller hydraulic cylinder, mounted
above this, was wired to a metal framework and radio transmitter.

"This setup will detect any incoming enemy shock waves," Tom said.
"We'll need fifty of 'em, so turn the job over to Swift Construction.
And have Uncle Ned put on extra shifts."

The Swift Construction Company, managed by Ned Newton, was the
commercial division which mass-produced Tom Jr.'s and Tom Sr.'s
inventions.

Information from the detector-transmitters, Tom went on, would be fed
into an electronic computer at the Bureau of Mines in Washington.

The Quakelizor itself was housed in a massive cube-shaped casting with
two large spheres mounted on top. From each of its four sides jutted a
hydraulic piston.

"How does it work, Tom?" Hank asked.

"Dual-control spheres on top," Tom explained, "will receive by radio
signal the pulse frequency com