or he sat up
as Frank was about passing.

"Hello! is that you, Frank Bird?" he asked, leaning forward to look
closer at the rider of the bicycle.

"Sure; just been up to your neighbor's, Lovejoy's, with some medicine
for his Sue," returned the boy, recognizing the farmer.

"How is the gal gettin' on?" called the other, over the canvas top of
his seat.

"Fine. No danger, dad says!" answered Frank.

"That's good!" he heard the sympathetic neighbor remark, as he moved on.

Five minutes later and Frank once more found himself approaching the
Whympers place. As before, the house was in complete darkness, as if the
inmates were long since abed. Frank knew that the old man kept early
hours, seldom sitting up, for he read much during the day, having
nothing else to look after.

Then, as was only natural, the eyes of the bicycle boy turned once again
with more or less affection toward the quarter where he could just dimly
make out the long, squat shed out in the field, in which the precious
monoplane was stored.

As he did so Frank uttered an exclamation of surprise.

"Why, there's a light over by the hangar!" he burst out. "Now, what
under the sun do you suppose that old fool of a Shea can be doing? Oh,
my! Look at the flame jump up! Why, as sure as you live I believe the
shed's afire! And I can see the figure of a man moving about. This is no
accident, but something worse! And it looks as if the little 'Bug' might
be going up in smoke in a jiffy unless I can sprawl over the fence here
and get on the spot mighty quick!"

CHAPTER V.

A WARM FIVE MINUTES.

"Fire! Fire!"

So Frank shouted, even as he jumped over the fence, and made a bee line
for the center of the big field, where the shed lay in which the
precious monoplane was stored.

He had hastily leaned his bicycle against the fence as he made the
plunge. Nor did he cease to let out constant yells while running across
the open as fast as his agile legs could carry him. Twice he tripped
over some object and nearly fell, only to recover himself and speed on.

As he ran he kept his eyes upon the low building beyond. In this manner
he plainly saw the stooping figure of a man or boy making off in a
roundabout way so as to avoid him.

Frank's heart was burning with indignation because of this dastardly
attempt to ruin the gallant little airship that had so nobly stood all
tests and proven itself a splendid piece of workmanship.

"Oh, the contemptible