hydroplane out in the Quackenboss pasture, I worked until eleven o'clock
in our shop, and then went home. This morning, early, after a bite to
eat, I hurried over there to do some finishing touches and carry the
thing out to apply to our broken plane, when to my astonishment I found
that the shop had been broken into later in the night, as well as our
hangar, where the aeroplane is usually kept. And here's what I
discovered lying on the work-bench, where the men had forgotten them."

With these words he held up the flashlight torch, and the twin black
masks; and they produced an immediate shock upon the Chief of Police.

"And you found those things in your workshop this morning, you say?"
he cried, reaching out to take hold of the torch, and the bits of black
muslin.

"Yes, and whoever was there, they must have been mad because they didn't
find the aeroplane, for they smashed a few things, just for spite, it
looked like," was what Frank added.

"Then, if it was the same men who robbed the bank they must have known
about you boys having a brand new machine. And say, that must mean one
of the robbers was something of a birdman himself; because no greenhorn
would ever think of making his getaway in an aeroplane. Don't you see
that's a pretty good clue, Frank? I'll remember that when I'm getting in
touch with other points, and find out if there's any aviator who's gone
crooked of late. Yes, that's worth knowing, now; and I'm glad you
mentioned it to me."

"What description did Cadger give of the men, Chief?" queried Frank.