on of the magnificent
machine. "Just you ask some one when you get home. Go to a machine
shop and ask 'em what an unbalanced condition will do to a high-speed
piece of machinery that isn't firmly fastened to a solid base."

"But I can't understand, you know," went on Dave, "just how it was
done. I know that you unbalanced the apparatus, but how should that do
such damage as this we see here?"

"Well, to be honest with you, I didn't expect that it would. My only
thought was to slip out the big bolt, put in enough lead to fill the
hole if I had time, and then let the vibration of the unbalanced
machine render it impossible for the aviator to steer or handle the
plane. I had not figured on anything giving way as it did."

"Then you don't want all the credit for wrecking the machine?" inquired
Dave, with a twinkle in his eye. "Is that it?"

"For some time I don't want any of the credit," replied Jimmie,
lowering his voice as an officer approached their position.

"Here comes a fellow," Dave stated, "that would probably be mighty glad
to connect us with the incident. But I know nothing!"

"Nor I!" declared Jimmie. "I didn't even see the thing happen!"

"That's true, too, as I can easily testify," added Dave.

Their visitor proved to be none other than von Liebknecht, the officer
in charge of the regiment, with whom they were now well acquainted.

"You boys are wanted at the rear," he announced. "Walk directly along
the train and report at the coach reserved for the Kaiser."

"Yes, sir," answered Jimmie, giving the Boy Scout salute. "And who
shall we find there to whom we shall report?"

"Fritz and Otto, whom you both know, will be on duty. Tell them that I
have sent you back and that you are there for special duty. They are
expecting you and will give you instructions."

"Very good, sir," replied Jimmie gravely. Then, as von Liebknecht
turned to proceed toward the little station building, he added:

"I see an accident has happened to the aeroplane. I hope the aviator
was not badly injured. They're carrying him away."

For a moment von Liebknecht paused to look searchingly into the face of
the boy. Jimmie returned his gaze unflinchingly. He said afterward
that it was quite the hardest thing he had ever attempted, and several
times he was on the point of letting his gaze wander. However, he
stood the ordeal well and presently heard the other say:

"He is not badly injured. A few minor contusi