that were said to be insurmountable, when we sailed in
our dandy little monoplane up to the crown of Old Thunder Top, and
snatched that silver cup for a prize? Make up your mind, my boy, that
that was just meant to get us in practice for better things. The time's
come for us to show what we're made of. And instead of a silver cup, the
prize this time will be--"

"My father's life!" murmured Andy, tears in his eyes, as he again
squeezed that faithful hand which held his so firmly.

"That's right," Frank continued. "We can go straight to this fine
Spanish gentleman, Senor Almirez, and get all the points he knows. From
there we'll get up-river to this valley town and visit Carlos Mendozo on
his cocoa plantation. Depend on it he'll be able to set us on the track,
somehow or other."

"Oh! it seems like a strange dream," said Andy, as he raised the piece
of bark to his young lips, and passionately kissed it, regardless of the
fact that some one passing the post office might notice him.

"Well, you want to wake up right away then," remarked Frank, smiling,
"because we've just got to get a hustle on us, if we're going to start
on this wonderful trip. Here's where our aeroplane is going to help us
out. Just imagine how we can pass over regions where it would be next
to impossible for us to navigate on foot--mountainous country, tropical
valleys where wild beasts roam and poisonous snakes abound; and jungles
where the natives have to cut a passage foot by foot, I understand, with
their _machetes_. And to think that we can sail freely over it all,
looking for that spot where that bark letter came from."

"Come, let's go home!" exclaimed Andy. "I'm sure Colonel Josiah will be
tremendously interested in what we've learned. He'll be the most
disappointed man in the whole U.S. just because he's so crippled that he
can't go along. For many years he's traveled in every country under the
sun. Perhaps he might tell us more about the interior of Colombia than
we know right now."

Accordingly they hurried away. Frank came near forgetting the news he
had been bearing at the time he met his cousin. But then, that was
hardly to be wondered at. The capture of the escaped robber was of minor
importance when compared with this wonderful business connected with
Professor Bird.

And just as Andy had said, Colonel Josiah _was_ tremendously interested
when he heard about it, and with his own eyes looked upon the letter
that had come from a li