"Well, it came mighty near being serious," remarked Mr. Sharp grimly. "Your father and I came back a little sooner than we expected, and as soon as I got near the house I heard your signal. I knew what it was in a moment. There were Mrs. Baggert and Garret talking away, and when I asked them why they didn't answer your call they said they thought you were merely tinkering with the machinery. But I knew better. It's the first time we ever had a use for 'forty-seven,' Tom."
"And I hope it will be the last," replied the young inventor with a faint smile. "But I'd like to know what Andy Foger is doing in this neighborhood."
Tom was soon himself again and able to go to the house, where he found Mrs. Baggert brewing a big basin of catnip tea, under the impression that it would in some way be good for him. She could not forgive herself for not having answered his signal, and as for Mr. Jackson, he had started for a doctor as soon as he learned that Tom was shut up in the tank. The services of the medical man were canceled by telephone, as there was no need for him, and the engineer came back to the house.
Tom was fully himself the next day, and aided his father and Mr. Sharp in putting the finishing touches to the Advance. It was found that some alteration was required in the auxiliary propellers, and this, much to the regret of the young inventor, would necessitate postponing the trial a few days.
"But we'll have her in the water next Friday," promised Mr. Swift.
"Aren't you superstitious about Friday?" asked the balloonist.
"Not a bit of it," replied the aged inventor. "Tom," he added, "I wish you would go in the house and get me the roll of blueprints you'll find on my desk."
As the lad neared the cottage he saw, standing in front of the place, a small automobile. A man had just descended from it, and it needed but a glance to show that he was Mr. Addison Berg.
"Ah, good morning, Mr. Swift," greeted Mr. Berg. "I wish to see your father, but as I don't wish to lay myself open to suspicions by entering the shop, perhaps you will ask him to step here."
"Certainly," answered the lad, wondering why the agent had returned. Getting the blueprints, and asking Mr. Berg to sit down on the porch, Tom delivered the message.