on for miles and miles around, provided he has a skilled companion
along to manage the aeroplane or balloon.

And that is destined to be the greatest value of these winged messengers
in future years, since it has been proven that they are not so very
dangerous after all in the line of dropping explosives upon battleships
or fortified places.

"Somewhere up yonder, Frank, they are probably hiding, and feeling
perfectly safe from pursuit," ventured Andy, who was sweeping the marine
glasses around and examining the country ahead with more than common
interest.

"Look how Old Thunder-top stands out today!" remarked Frank, turning for
just an instant to glance upward toward the left, where the high
mountain towered, its heavily wooded sides looking as gloomy as ever,
and the white cliffs that made the summit inaccessible to human feet,
appearing almost dazzling in the glittering light of the undimmed
morning sun.

"And say, there's our old friends, the eagles that had a nest up there,
and gave me such a warm time when we first reached the top." Andy cried,
as he focused his glasses on a sweeping pair of huge birds that were
heading their way, as if meaning to investigate, and find out what
manner of rival this could be, invading their native element.

"They know too much to bother with an aeroplane by now!" declared Frank,
laughing again. "Why I'm thinking those birds have hardly grown new
feathers in place of the lot they lost that time they fought us so
savagely."

The memory appeared to amuse his cousin also, for he could be heard
laughing heartily, even above the purr of the now steadily going motor
that sent the propellers whizzing around so rapidly; for there was one
fore and aft, as is the case with all biplanes, the engine being behind
the pilot and his companion.

"Tell me if you can remember, was that other aeroplane headed straight
up the lake the last you saw it in the early morning light?" Frank
asked.

"That's right, Frank; but then I couldn't say just how long they kept
along that same course. When those hundreds of old crows came sailing
along on the wind, cawing to beat the band, and going every-which-way, I
lost sight of the biplane. After that it would have to be just guess
work."

"But we've got a good pointer to start with," insisted Frank. "They
wouldn't be so apt to head toward the south, east or west, because in
those directions there are plenty of towns and villages, and these could
rep