"Nothing so far, Tom," replied Jeff. "But it must be something big. He packed a lot of gear into a jet boat and blasted out of here this morning."
"What do you suppose it is?" asked Astro.
"I don't know," replied Jeff. "I can't even guess."
"I can," said Roger, "and if it's what I think it is—well, I just hope it isn't, that's all." The blond-haired cadet stopped talking abruptly.
Tom, Astro, and Jeff looked at each other. Finally Tom asked, "Well, what do you think it is?"
"There's only one thing I know really well, Tom," replied Roger. "Just one thing, and that's electronics. I may be a jerk about a lot of things, but I know electronics."
"O.K.," said Astro. "You know electronics. But what has that got to do with the instruments going out of whack?"
"The only natural element that would cause such disturbance is uranium."
"Uranium!" breathed Tom. "You mean uranium pitchblende?"
"I mean uranium!" snapped Roger. "Uranium pitchblende isn't concentrated enough to cause a reaction like that on the instruments. It would take a big chunk of pure uranium to do the job."