"When do you expect the government experts?" Ned asked.
"Within a few days, now. But I'll have to hustle to get ready for them, as this fire has put me back. There are quite a number of details I need to change. Well, now, let me explain about that gun recoil business. Maybe you can help me."
"Fire away," laughed Ned. "I'll do the best I can."
Tom led the way from the main shed, where the aerial warship was housed, to a small private office. As Ned entered, the door, pulled by a strong spring, swung after him. He held back his hand to prevent it from slamming, but there was no need, for a patent arrangement took up all the force, and the door closed gently. Ned looked around, not much surprised, for the same sort of door-check was in use at his bank. But a sudden idea came to him.
"There you are, Tom!" he cried. "Why not take up the recoil of the guns on your aerial warship by some such device as that?" and Ned pointed to the door-check.
CHAPTER VII
WARNINGS
For a moment or two Tom Swift did not seem to comprehend what Ned had said. He remained staring, first at his chum, who stood pointing, and from him Tom's gaze wandered to the top of the door. It may have been, and probably was, that Tom was thinking of other matters at that instant. But Ned said again:
"Wouldn't that do, Tom? Check the recoil of the gun with whatever stuff is in that arrangement!"