where they are needed to destroy a
battery, or whatever is the object aimed at. The observation complete,
the machine goes back over its own lines--if the Germans let it.

This sort of work was going on below them while Tom, Jack and the others
in the Nieuports were engaging in mortal combat with the Hun fliers.
Some of the heavy French shells fell beyond the emplacements of the big
guns, and others were short. The observers quickly made corrections by
wireless for the gunners. Tom Raymond, after a desperate swoop at his
antagonist, sent him down in flames, and then, seeking another to
engage, at the same time wondering how Jack had fared, the young aviator
looked down and saw one of the largest of the French shells fall
directly at the side of the foremost of the three German giant cannons.

There was a terrific explosion. Of course, Tom could not hear it because
of his height and the noise his motor was making, but he could see what
happened. A great breach was made in the long barrel of the German gun,
and its emplacement was wrecked, while the men who had been swarming
about the place like ants seemed to melt into the earth. They were
blotted out.

"One gone!" exclaimed Tom grimly. And then he noted that the other two
guns had been withdrawn beneath the camouflage. They were no longer in
sight, and hitting them was a question of chance.

Still the French batteries kept up their fire, hoping to make another
hit, but it would be a matter of mere luck now, for the guns were out of
observation.

The airmen observers, however, still had a general idea of where the
super-weapons were, and the French gunners continued to send over a rain
of shells, while the bombing machines, save one that had been destroyed
by the German fire, kept dropping high explosives in the neighborhood.

"The place will be badly chewed up, at any rate," mused Tom.

He glanced in the direction where he had last seen Jack, and to his
horror saw his chum's machine start downward in a spinning nose dive.

"I wonder if they've got him, or if he's doing that to fool 'em,"
thought Tom. As he was temporarily free from attack at that instant he
started toward his friend. Hovering over him, and spraying bullets at
Jack, was a German machine, and Tom realized that this fighter might
have injured, or even killed, Jack.

"Well, I'll settle your hash, anyhow!" grimly muttered the young birdman
to himself. He sailed straight for the Hun, who had not yet