. We just have to keep them at a distance and
take our chances."

"But Frank--"

"Yes, I know what you're going to say, Andy; that night will soon be
coming swooping down on us. That's so, and I'm sorry in one way, for
it's going to be a tough old job finding a suitable place to fold our
wings on in the darkness. But we're up against it good and hard, you
see, and it's what you might call Hobson's choice."

Andy showed more positive signs of anger.

"What business have they got bothering us this way?" he grumbled. "Say,
don't you suppose it would be all right for me to try a few shots at 'em
with the fine Marlin repeating rifle we're carrying? Perhaps I could
give 'em a scare anyhow and make 'em haul off."

"No, I wouldn't think of it," replied Frank, hastily. "You might cause
trouble to our own delicately balanced little aeroplane by firing. And
then again, what if you brought about an accident and sent them down to
the earth like so many stones?"

"But you know those other chaps banged away at us and they didn't bother
their heads a cent whether they upset our whole business or not,"
objected Andy, belligerently.

"Two wrongs never make a right, Andy."

"But when they opened fire on us," the other went on, complainingly,
"that constituted a declaration of war, and so you sec, we'd be quite
justified in giving 'em back the same kind of medicine."

"You forget that one of those two in the biplane is a former schoolmate
of ours and that perhaps he's just being compelled to chase us right
now," said Frank.

"Think so, do you?" growled Andy, above the rattle of the exhaust;
"well, I'd like to warrant you that Puss Carberry is grinning right now,
because of the fright he thinks he's giving us. No, sir, he's only too
willing to do anything to upset our plans. I know him pretty well, and I
wouldn't put any meanness past that fellow."

Frank in secret did begin to feel more than anxious. The afternoon was
almost over and the sun perilously near the western horizon. Too well
did he know how rapidly darkness came after the disappearance of the
king of day.

He bade Andy pay more attention to the lay of the country ahead of them.

"We're keeping well ahead of the biplane," he observed, "and there's
little danger of their overtaking us. But in case they drop out of the
race we must try and know something of the chances for a landing
ourselves."

"Gee! it looks pretty punk down there!" admitted Andy, after he had