quakes?"

"It must be," Tom declared. "It's the only possible explanation."

"Good night!" Bud gasped weakly. "What a weapon! Just push a button
every so often and you could blow up another country bit by bit--and no
one could ever prove who was behind the attack!"

Tom nodded. "Enough to make every American shiver, if he only knew!"

"What can we do about it?" Bud asked.

Tom resumed his worried pacing. "I'll have to invent a shock-wave
deflector, Bud. It must be done in a hurry, too. Our enemy may start to
destroy American cities as well as vital defense plants!"

Immediately Tom put through an urgent call to an eminent scientist in
Washington who was a member of the National Research Council. Quickly he
outlined a plan.

"Tom, I'll talk to the president's special science adviser at once," the
man promised. "I'll try to set up a meeting for ten o'clock tomorrow
morning at Enterprises."

Feeling relieved, Tom left the plant with Bud. The two boys drove off to
attend church with Mrs. Swift and Sandy. Then, after the Sunday midday
meal, Tom returned to his laboratory to work on ideas for a shock-wave
deflector.

Bud and Sandy, meanwhile, drove to the Shopton Yacht Club to inspect the