"No need to," replied the other, instantly; "because it's hunting us."

They were very careful to make sure that no loose stones barred the
way; for as the plateau was very short they must sail off into the air
almost immediately on starting the engine; and even a small turn at
such a critical moment was apt to cause the biplane to swerve, and
bring about a catastrophe.

But the start was successfully accomplished. Frank always paid so much
attention to little things that he was not very apt to be caught
napping.

"Straight home?" asked Andy, once they were afloat, and heading down
from the dizzy height.

"Yes," replied his cousin. "I'm curious to hear what our friend Mr.
Marsh could have had to say to Larry; and how the boy carried out his
job of keeping strangers from nosing around inside the shop."

"Just as well that we left when we did," remarked Andy; "for over in
the southwest I noticed some clouds that may bring a lot of wind along,
and weather that no self-respecting aeroplane has any business to be
out in."

"Why, yes, I've seen the peak of Old Thunder Top buried in low hanging
clouds many a time," Frank declared. "And it wouldn't be the nicest
thing in the world for us to be caught up there, with a wild storm
raging."

"Ugh! deliver me from that experience," grunted Andy, turning his head
to look back toward the peak they had just left, and which was already
far astern, so rapidly did the little but powerful Kinkaid engine whirl
the biplane onward, when let out to its limit.

Frank kept his eyes ahead; but he knew when his companion gazed toward
the dense woods away off to the right, where they had been fired at by
the unknown marksman.

"Still harping on that bang, eh?" he observed.

"Yes, and I won't have any peace till we find out who fired that shot,"
answered the other, doggedly. "Just think how nasty it is to never
know when you're going to be potted, like an old crow! It takes most
of the fun out of flying, that's what."

"Well, wait a little, and perhaps we may learn something," Frank went
on; and before his companion could make any remark he suddenly switched
the conversation by saying: "the boys are waving their hats to us, and
I thought I got a faint yell; but the breeze is dead wrong for hearing.
I'm tickled to death with the handsome way the machine carries herself;
and that's a satisfaction worth while, eh?"

So Andy stopped twisting around to look back, and confined his
a