All that day they traveled, Tom and his chum keeping a lookout for the blue machine, but not seeing it. The young inventor had so laid his plans that before it got too dark he descended in a broad field on the outskirts of a big city. As the aeroplane was large enough to permit of sleeping in it and as Tom had brought along blankets, they decided to spend the night in the Blackbird.
It was the next morning about nine o’clock, and just about the time Tom and Ned were taking off again on the second day of their trip, that Mr. Swift was summoned to the telephone in his office.
“Dey’s somebody dat wants to talk to you ’ticklar like,” reported Eradicate.
“Perhaps it’s a message from Tom!” exclaimed Mr. Swift. “He may have caught the robbers and gotten back his chest.”
“No, sah, it don’t sound like Massa Tom,” said the colored man.
The voice to which the aged inventor listened was not that of his son. Instead, over the wire came strange tones asking:
“How much will you pay us for the return of your chest of secrets?”
Mr. Swift was so surprised that he almost dropped the receiver.
CHAPTER XXIII
THE BLUE MACHINE
Barton Swift was the true father of his energetic son, and Tom inherited his qualities from his father. Which is to say that in his youth Barton Swift had been fully as active and quick as was now the young inventor.