Relieved, the two scientists went back to work on their sensing experiments. Twenty minutes later the signal bell rang again on the electronic brain.
"This time it must be Exman!" Tom cried.
The unreeling tape quickly bore out his guess.
EXMAN TO SWIFTS. TWENTY-FOUR-HOUR EARTHQUAKE UNDER HIGH LOYALTY.
"What!" Tom stared at the tape, his brow creased in a puzzled frown. "That 'twenty-four-hour earthquake' bit must mean he's warning us that a quake will occur in twenty-four hours. But what about the rest of it?"
"Hmm... 'Under high loyalty.'" Mr. Swift was as baffled as Tom. He studied the message for several minutes. It seemed highly unlikely that the electronic brain had made an error in decoding. Any new or untranslatable symbol caused a red light to flash on the machine.
"I think the only thing we can do is signal Exman and ask for a clarification, Tom," Mr. Swift decided at last.
Tom agreed. He beamed out a hasty code signal:
EXPLAIN MESSAGE.
Seconds later came Exman's reply. It was identical with the first message: