versation, the boys gathered that Fritz was engaged in the task of
building an aeroplane, and they were greatly interested.

The fact that no one was allowed in Fritz's workshop unless he
accompanied them, and the additional fact that at night two soldiers were
stationed at the door at first caused the boys some surprise. However,
Fritz had explained:

"You see, the government has taken over all aircraft in process of
construction, no matter how crude and amateurish, and has appointed a
commission to investigate all patents. Of course, it was known that I
was building an airship, and, as a result, I am working under
government orders.

"If my craft should come up to expectations it will mean a great deal to
me, and I probably shall either be put to work building more, or, better
still, be made a member of one of the aeroplane corps."

"Yes," said Chester again, "Fritz is a fine fellow. Do you suppose his
aeroplane will be a success?"

"I don't know. For his sake, I hope so. As he says, it means a whole
lot to him."

"So do I. And I will bet Fritz would be of great help to his country. He
is a pretty shrewd chap."

"You bet he--Hello! What's that?"

A sudden cry had come from the direction of the kitchen, and the sounds
of a struggle followed.

"Come on!" shouted Chester. "Somebody is in trouble!"

The two boys ran madly around the house.

Dashing through the door into the kitchen, a terrible sight met
their eyes.

Huddled into a corner was Frau Schmidt, and over her, with a naked
knife, stood a man, ragged and unkempt. A second man was ransacking the
drawers of a dresser in the room beyond. The boys could see him through
the open door.

Just as they dashed in the door, the man with the knife snarled in a
low voice:

"Give me the key to the workshop, I tell you. We mean business!"

"You mean business, do you!" shouted Hal, striding toward him.
"Well, so do I!"

The man turned at the sound of Hal's voice, and, with upraised knife,
awaited the lad's attack.

"You cowardly ruffian!" cried Hal, "to attack a defenseless old woman!"

As he spoke, he leaped upon the man, dodging the blow the latter aimed at
him with the wicked-looking knife. Before the latter could recover his
balance, Hal seized the arm that held the knife.

A sharp twist and the knife went spinning across the floor. Both leaped
for it, but Hal was quicker than his opponent, and placed his foot upon
the weapon. With a snarl the man sp