nd a cool calculating eye Jacques sat in the
pilot's seat and directed the course of his flier. Earl and Leon held
the machine-gun ready for instant action.

"We're almost over the battle-line," announced Earl suddenly. "I can
see the trenches below."

"Never mind them," exclaimed Leon. "Watch that machine."

"He's smaller than we are," said Earl.

"There are only two men in it too," added Leon.

"Get ready," ordered Jacques suddenly.

As the two machines approached each other Jacques all at once elevated
his front plane and the big French flier rose swiftly higher and
higher. The opponents were scarcely a half-mile apart now and as the
monoplane in which the three young soldiers of France were seated rose
above its adversary Leon and Earl opened fire with the machine-gun.

The Germans replied but the aim of each was poor and the two fliers
swept past each other unharmed.

"Turn around, Jacques, and go back after him," cried Leon excitedly.
"We'll get him next time."

With a wide graceful sweep Jacques turned the big monoplane and
advanced again to the attack. The German also had wheeled and once
again the two machines approached each other, maneuvering for position.

"Be careful now," warned Jacques. "We can't afford to miss many times
for you may be sure he won't."

"Get above him, Jacques," cried Earl. "That's our best chance."

They were high above the summits of the Vosges now: the air was
bitterly cold, but the three young aviators did not notice that fact.
Neither did they notice that in their maneuvers they had crossed the
battle line and were now flying over territory occupied by their foes.
Their one object was the German aeroplane and everything else had been
forgotten in their desire to accomplish its downfall.

Around and around the two machines flew, each one trying to force its
opponent into a position of disadvantage.

"We're faster than he is, Jacques," cried Leon. "Follow him up from
behind and go higher than he does."

"I don't believe we can do that," exclaimed Jacques doubtfully.

"Try it," urged Leon eagerly.

"I'll try it."

Jacques skillfully wheeled the machine and describing a great loop,
doubled on his course. Meanwhile he rose to greater and greater
heights. The earth was now many thousand feet below; even the clouds
were beneath them in many instances.

"He's running away," cried Earl suddenly.

"After him, Jacques! After him!" shouted Leon.

The German,