ll only carry two."

"Why, yes," answered Hal; "I would like it."

"Climb in, then," ordered Fritz.

Not without some misgiving Hal obeyed.

Once more the huge machine skimmed gracefully over the ground, and again
went sailing into space.

As the plane rose from the ground, Hal grabbed the side of the seat and
hung on for dear life. Looking down and seeing the ground dropping
rapidly away, he experienced a choking sensation in his throat.

As the machine stopped rising, however, and stretched itself out for a
straight flight, Hal's composure came back to him, and he looked around
with interest.

Then Fritz explained the mechanism of the machine to him. He showed him
how to stop, how to increase the speed of the plane; how to rise and how
to glide to earth. He also showed him how to work the steering wheel.

While they were sailing about in the air he told Hal that, if necessary,
his craft could make a speed of one hundred miles an hour for hours. He
declared it could attain an altitude of a mile. Practically the only
danger, he said, came from conflicting air currents.

After sailing around for nearly half an hour, Fritz again brought the
machine to the ground a few feet from where Chester stood.

"Great!" exclaimed Hal, as he alighted and helped Fritz roll the machine
back into the shop. "No more automobiling for me. When I get home I am
going to get an airship."

"Wouldn't you like to go up with me to-morrow, Chester?" asked Fritz, as
he locked the door to the shop.

"I believe I would," was the reply. "I guess I can stand it if Hal can."

"Then you shall," said Fritz, and the three turned toward the house,
where Frau Schmidt stood in the doorway, calling to them that supper
was ready.

CHAPTER X.

IN THE AIR.

The boys were busily engaged in disposing of a hearty supper when there
came a knock at the door. Frau Schmidt answered the knock, and, returning
a few moments later, placed before Hal an important-looking letter,
bearing the official seal of the German government.

Hal opened the document and read.

"Great Scott!" he exploded, after a hasty perusal.

"What's the matter?" demanded Chester anxiously.

"Why, here is an order, commanding us to report to the commanding
officer the first thing in the morning, so that we may be transported
back to Berlin!"

"Berlin! What in the world do we want to go back to Berlin for?"

"We don't; but it looks as though there were no help for it.