stared
after them as though hardly knowing what to make of it all; but they
could hear the good woman begin to explain, and had no doubt she would
be able to satisfy his reasonable curiosity.

For the time being the Bird boys must forget all about what lay in the
past, because it was the future that should interest them wholly. They
had reached a point in the hunt where perhaps a sudden change of plans
would be necessary; particularly if those they followed had taken the
alarm, and were ready to shake the dust of this section of the country
from their shoes.

Away from the farmhouse hurried the two young aviators, making as near a
bee line for the field where they had left their aeroplane as they could
possibly manage, and all the while searching the sky for signs of the
other flying machine.

CHAPTER XVIII

AN AEROPLANE CHASE

"Here it is, and everything seems all right!" remarked Andy as they
reached the field, and found the hydro-aeroplane just where they had
left it.

"Yes, no one has disturbed a thing, which I think is lucky for us,"
Frank went on to say, as he proceeded to put back the small part he had
taken away with him, and thus place the machine in perfect condition for
business.

Andy moved about, looking to see that all obstacles threatening to
interfere with a successful launching were removed from in front of the
waiting aeroplane.

So minutes passed, until at least ten had crept by since their coming.
Frank had everything tuned up, and knew of not the least chance where he
could improve the conditions of planes or motor, for all seemed to be as
nearly perfect as they could be made.

Both boys cast frequent glances aloft, and as a rule toward that
particular quarter where they presently expected to see something
moving. They were keyed up to a pretty lively pitch of excitement,
though Frank did not show it half as much as his younger cousin, who was
always affected this way.

Then suddenly Andy called out:

"There she rises, Frank! Oh! look at them boring up, will you, in that
corkscrew spiral way! Tell me that Casper Blue doesn't know his
business; Perc will never get as much out of his biplane as that old and
experienced aviator means to. Are we going to follow suit, Frank?"

"Get aboard!" came the prompt answer; and it was almost laughable to see
how nimbly Andy obeyed this order.

Frank lost no time in starting, and they went away with a rush, passing
over the abandoned fiel