“And let those kids get away with what they did?  Not much, dad.  We’ll give them a lesson they won’t forget in a hurry.  Come on.”

He began climbing the ladder.  Behind him came his worthy parent, and Tam formed the last member of the now silent procession.  The Norwegian carried a bulky package of some kind, the contents of which it would have been impossible to guess save that it gave out a metallic sound as Tam moved with it.

Dan Cassell reached the window, slid it noiselessly back in its grooves and then, crawling through, dropped lightly to the floor within.  He was followed by his father and Tam.

But Jimsy slept on.  Slept heavily and dreamlessly, while deadly peril crept upon him.

CHAPTER X.

PEGGY’S INTUITION.

The movements of the invaders of the stable, which now housed the “winged steeds” of the young aviators, were mysterious in the extreme.  The Norwegian carried a tin can containing some sort of liquid which he was ordered to pour about the floor in the neighborhood of the aeroplanes.  This done, Dan Cassell collected several scraps of litter and made quite a pile of it.

“All ready now, I guess,” he said, with what was meant as an attempt at a grin.  But his lips were pale, and his forced jollity was a dismal failure.  As for his father, he made no attempt to conceal his agitation.

“Dan, they may be burned alive,” he faltered; “better call it all off.”

“Not when we’ve gone as far as this with it,” was the rejoinder; “give me a match.”

“Dan!”

“It’s all right, dad.  They’ll wake in time.”

“But if not?”

“Then they’ll have to take their medicine.”

With fingers that trembled as if their owner was palsied, Jim Cassell handed his son some matches.  The latter took one, bent low over the pile he had collected and struck the lucifer.

A yellow sputter of flame followed, and the next instant he was holding it to the pile of litter which had been previously soaked by the contents of the Norwegian’s can.

But before he could accomplish his purpose and set fire to the pile of odds and ends saturated to double inflammability by the kerosene the Norwegian had carried, there came a startling interruption.

There was a knock at the door and a girlish voice cried: 

“Roy!  Roy, let me in!”

“Furies!” exclaimed Dan Cassell under his breath.  “It’s one of those girls.”

“Come on.  Let’s get away quick!” exclaimed his father, trembling from nervous agitation.

“Not before I set a match to this,” exclaimed Dan Cassell viciously.

He touched the match to the pile and the flames leaped up.

“Now for our getaway,” he cried, and the three fire-bugs ran for the window by which they had made their entrance.

In the meantime a perfect fusillade of blows had been showered on the door outside.  Jimsy awoke just as the last of the three midnight intruders vanished through the window.  His first instinct was a hot flush of shame over the feeling that he had betrayed his trust.