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.
