inent place in their thoughts.
For the very next morning, when Paul and John arrived at the hangar,
they were met at the door by a very agitated Bob Giddings.

"Fellows, what do you think has happened?" cried Bob, clearly very much
excited. Without giving his friends time to answer the question he
blurted out: "Somebody got in here last night and stole our plans!"

"Stole our plans!" reiterated Paul and John in the same gasp.

"That's it," said Bob,--"stole the set of blue-prints we have been
working from. What's more, they must have seen the airplane before
they got out. I went to take the plans out of the bench drawer here
where we have kept them locked up, and there was the drawer wide open,
the lock picked, and the drawings gone. I'll bet a herring we can
thank my dark-skinned shadow of yesterday for this little visit!"

"It does look as if he might have had something to do with this,"
agreed John soberly. "I wonder how the rascal, whoever he is, could
have gotten in the building. There's a heavy Yale lock on the doors."

"The doors were locked all right when I came this morning," vouched
Bob. "I don't see myself how--"

"Here you are, gentlemen!" called Paul, who had stepped to a good-sized
window near the head of the workbench. "Here's the fellow's private
entrance!" And he pointed to where a heavy nail locking the lower sash
had been forced aside, also to a series of indentations in the outer
sill, where some prying tool had obviously been recently at work.

"It's a clear case of theft, that's sure," observed John; "and since
its only our plans that have been taken, it goes to show that this chap
is very much concerned about this new airplane."

"Perhaps he wishes to beat us out in getting the patent rights," Bob
hinted darkly.

"No, I don't think it's that," differed Paul; "our application was sent
in to Washington some weeks ago, and you know the first one to apply
for a certain patent gets the attention."

"Well, then, he could use our plans and make and sell airplanes of
their pattern, couldn't he?" asked Bob, whose ideas of patent laws were
still a little vague.

"Not at all; if he did we could sue him for infringement," was Paul's
answer. "The only way he could profit by this theft, so far as I can
see, would be to construct a machine for his own private use, or to
give to another person. We could not touch him for that."

"And that would be bad enough for us--if such a machine were