as really what the boys feared the most--that their quarry slip
off in secret, when they were far away.

Frank was indeed trying to figure out whether it would not be best after
all for him to stay by the hydroplane, on guard as it were, while Andy,
by using a horse, if the Hoskins happened to still possess such an
animal, managed to get to another farm, where they were up-to-date
enough to have a telephone in the house, by means of which he could get
in touch with Dr. Bird or Judge Lawson in Bloomsbury.

Then again, there was always a slight chance that this pretended
professor might have seen them descend, while he was wandering around.
Once an airman, and just by instinct as it were, the eyes are almost
constantly searching the heavens, perhaps for a glimpse of other
adventurous craft, or it may be, signs that give warning of treacherous
winds, gathering storms, or similar things that must always be of
intense interest to an aviator.

And so while Casper Blue had long since given up taking hazards in a
flying machine to indulge in even more dangerous business as a bank
robber, still habits would cling tightly, and thus he might have seen
more than the ordinary man could have done.

Of course, even though he sought the hydroplane, and found it lying
there in the field, he could not very well make any use of it so long as
Frank held the missing part in his possession.

But he could in a spirit of maliciousness so utterly destroy the planes,
and even injure the powerful little Kinkaid engine that it would be
practically fit only for the scrap-heap afterwards. And that was giving
Frank more or less concern, even while he continued to linger at the
farmhouse because Andy wished to prowl around a little while longer in
hopes of getting some clue to the location of the cache where the
thieves had hidden their plunder.

Sallie saw nothing strange in this apparent desire of Andy to hang
around. She was rather a pretty little thing, and of course knew it; so
that she may have believed the witchery of her attractions had more or
less to do with the matter.

Even when Frank asked so many queer questions about the absent boarder,
Sallie was not wise enough to understand that the boys Were much more
concerned about how Professor Whitesides amused himself, where his
favorite lounging places seemed to be, and all that, rather than in her
pretty face and merry laugh.

Her mother must have counted on having her assistance in