time last night, and ran
away with my biplane!"

Upon hearing these astonishing words it was little wonder that Andy and
Frank once more looked at each other, with the light of understanding
dawning on their faces.

CHAPTER VI

FIGURING IT ALL OUT

"That's a strange story you're telling us, Percy," said the Head of the
local police force, at which the boy bridled up immediately.

"I don't see what there is so funny about it, Chief!" he exclaimed,
frowning. "I tell you my hangar was broken open last night, and I'm out
a biplane that cost me a good round sum. It's up to you to get on the
track of the same, and recover it. I hereby offer a reward of three
hundred dollars for the recovery of my machine uninjured, and make it
five hundred if the thief is captured in the bargain."

When he said this Percy assumed all the airs of a millionaire; but then
it was well known about Bloomsbury that the Widow Carberry was very
wealthy; also that her only hopeful could wheedle her in to settling any
sort of a bill he chose to contract, so that the mention of the sum of
five hundred dollars was not anything extravagant for Percy.

"Oh! it wasn't that I doubted your word at all, Percy; don't think
that," Chief Waller hastened to say; for like most men he was ready to
bow down in front of the golden calf; and more than once Mrs. Carberry
had been very generous to the force--when her house took fire and came
near burning, but was saved, thanks to the energetic work of police and
fire departments; and again, when a hired man tried to carry off some of
her jewelry, but had been easily caught, and the plunder restored.

"Then what makes you act like that, I'd like to know?" demanded Percy,
looking very much put out, as though he did not like to be treated with
suspicion, especially when his old-time rivals, the Bird boys, were
around.

"Why," the officer went on to say, "when you said that about your
aeroplane being taken, it struck me all in a heap; because Frank here
was just telling me that two men broke into his shop last night after
eleven, and knocked things around, just because they failed to find his
hydroplane in its bunk as usual. They wanted that machine, and wanted it
so bad, that, as a last resort, they went over to your place, and
confiscated your biplane."

It was Percy's turn now to look astonished. He even condescended to
notice the presence of the two Bird boys, and surveyed them with
interest.

"Is