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!"