Hopefully the Swifts stood by the machine. Would their space friends agree? As the minutes went by without a response coming through, father and son exchanged anxious glances. "They've _got_ to let Exman stay, Dad!" Tom said. Mr. Swift nodded. "I'm afraid, though, the space beings have decided otherwise. They--" He was interrupted by the ringing of the alarm bell. "Message, Dad!" Tom said tersely. A moment later they were overjoyed to see three words appear on the tape: VISIT EXTENSION GRANTED. 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: TWENTY-FOUR-HOUR EARTHQUAKE UNDER HIGH LOYALTY. Tom and Mr. Swift stared at each other anxiously. "Good night, Dad! This is horrible!" Tom exclaimed. "Exman sends us ample warning of a disaster and we're stymied!" [Illustration (Tom Jr. and Tom Sr. read a message from Exman)] "Hi! What's going on, you two?" asked a merry voice. "More heavy thinking?" Sandy Swift stood smiling in the doorway. The smile gave way to a look of concern as Tom explained the crisis. "How dreadful!" Sandy gasped. "We _must_ figure out what it means!... Wait a minute!" Tom looked at her expectantly. "Got an idea, Sis?" "Well..." The pretty, blond teen-ager hesitated. "You don't suppose Exman might have been translating some foreign words with a meaning similar to 'high loyalty'? For instance, high loyalty could mean 'good faith.' I know that in Latin 'good faith' would be _bona fide_." "Sandy! You've guessed it!" Tom crossed the room in a single bound, gave his sister a quick hug, and whirled her around. "Exman must mean the Bona Fide Submarine Building Corporation! He didn't dare risk telling us the exact translation." "Of course!" Mr. Swift was equally jubilant. But his face was grave as he added, "The company's located on the West Coast close to the San Andreas fault. Tom, a quake in that area could be devastating!" "You're right, Dad," the young inventor replied. "I'll call Dr. Miles and Bernt Ahlgren at once!"