ay," returned the willing Andy. "I tell you what, Frank,
let's go up to the top of the mountain again. Haven't been there this
season, you know."

"Just what I had in mind myself, and I think you knew it," Frank said,
as he led the way outside. "Then we might sail around over the woods
up in that region where we discovered those two hiding jewelry thieves,
who were making headquarters of that old shack in the forest. If this
biplane can climb any better than our little Bug used to do, she'll be
a wonder, all right. Come on, and help us get things moving, fellows."

Many hands made light work, and presently the biplane was ready for the
start.

When Frank gave the word the others pushed her off; and as the two
propellers hummed, the machine started along the ground on the three
bicycle wheels until presently it arose in the air as gracefully as any
bird could have done.

"Now, which way first?" asked Andy, when the shouts of their comrades
had died away in the distance, and they were half a mile from the
trying-out field.

"I guess we'll take a little twenty-mile spin first," Frank replied,
moving a lever; "to see what she can do in a hurry pinch. That new
engine seems to work all right; just as the smaller one did, seldom
failing us. Tell me, what could be as fine as this, sailing over the
earth? I don't wonder that when a fellow has once started in to be an
aviator he can't ever break away. Peril and accidents he laughs at;
not because he's reckless always, but just on account of the
fascination of the sport."

"We're the luckiest fellows ever, just as Larry and Elephant say," Andy
declared as they soared upward, and then descended in daring spirals as
Frank tried out the new airship, to see what it was capable of doing.

In a dozen ways had it proven even more than they had expected, and
both boys were wild with enthusiasm over the performance.

"Let Percy come along with his new one!" cried Andy, after they had
volplaned successfully down toward the earth, until not more than a few
hundred feet above the tree tops of the forest; "it would tickle me to
have a turn with him again. He has forgotten his other beat, and is
beginning to boast again about what great stunts he means to kick up."

"Well, who knows what may be in store for us yet," Frank remarked; "and
now, let's head up again, and strike for the summit of Old Thunder Top,
ten miles away."

"Oh!"

Andy's sudden exclamation was caused by