gainst your shoulder.
That part was the recoil, and it is the recoil of the guns I figure on
putting aboard my aerial warship that is giving me such trouble."

"Is that what makes you look so blue?" asked Ned.

"That's it. I can't seem to find a way by which to take up the recoil,
and the force of it, from all the guns I want to carry, will just about
tear my ship to pieces, I figure."

"Then you haven't actually tried it out yet?" asked Ned.

"Not the guns, no. I have the warship of the air nearly done, but I've
worked out on paper the problem of the guns far enough so that I know
I'm up against it. It can't be done, and an aerial warship without guns
wouldn't be worth much, I'm afraid."

"I suppose not," agreed Ned. "And is it only the recoil that is
bothering you?"

"Mostly. But come, take a look at my latest pet," and Tom arose to lead
the way to another shed, a large one in the distance, toward which he
waved his hand to indicate to his chum that there was housed the
wonderful invention.

The two chums crossed the yard, threading their way through the various
buildings, until they stood in front of the structure to which Tom had
called attention.

"It's in here," he said. "I don't mind admitting that I'm quite proud
of it, Ned; that is, proud as far as I've gone. But the gun business
sure has me worried. I'm going to talk it off on you. Hello!" cried
Tom suddenly, as he put a key in the complicated lock on the door,
"someone has been in here. I wonder who it is?"

Ned was a little startled at the look on Tom's face and the sound of
alarm in his chum's voice.

CHAPTER II

A FIRE ALARM

Tom Swift quickly opened the door of the big shed. It was built to
house a dirigible balloon, or airship of some sort. Ned could easily
tell that from his knowledge of Tom's previous inventions.

"Something wrong?" asked the young bank clerk.

"I don't know," returned Tom, and then as he looked inside the place,
he breathed a sigh of relief.

"Oh, it's you, is it, Koku?" he asked, as a veritable giant of a man
came forward.

"Yes, master, it is only Koku and your father," spoke the big chap,
with rather a strange accent.

"Oh, is my father here?" asked Tom. "I was wondering who had opened the
door of this shed."

"Yes, Tom," responded the elder Swift, coming up to them, "I had a new
idea in regard to some of those side guy wires, and I wanted to try it
out. I brought Koku with me to use his strength o