a "looker-on?"

How eagerly did his heart throb with renewed hope each time he
discovered signs of another attempt on the part of the enemy pilots to
engineer a raid that might check this observation work. They knew what
it was doing to advance the cause of the battling French; and that, as
often proved to be the case, the airplanes were again the "vigilant eyes
of the army."

It was well along in the morning when Tom Raymond's time came. The
fighting below had been going on for some time, and from fugitive
glimpses Tom snatched every now and then as he looked down, he had
reason to believe things were moving successfully for the assailants. At
least the French troops occupied a long line of trenches where the
Boches had been in possession at the close of the previous day.

Yes, there was another burst of ambitious fliers rising to take a
chance. The fact that already seven of their men had been dropped,
several with their planes ablaze, did not deter them; for those German
airmen had often proved their courage and were known as stubborn
fighters.

Soon another battle below the clouds was in progress. Besides Tom, there
were now only three of the Americans in the air, the remainder having
been driven down, some in trouble of some kind, others to replenish
their supplies. And there were _four_ enemy planes, Tom noticed,
even as he watched the machine of the captain and received the signal to
attack the latest arrival in the enemy squadron.

CHAPTER IX

WINNING HIS SPURS

"At last!"

Those were the expressive words that broke from Tom Raymond's lips when
he saw the commander give him the long-anticipated signal. Tom had
already discovered his intended antagonist. A fourth plane was coming up
quickly. It had held back to await the chance that would be offered when
the three defenders of the fire-control machine were hotly engaged with
the trio of skillful Boche pilots.

The game was very apparent. It was likewise exceedingly old. The French
commander was too experienced an aviator to be so easily caught. That
was why he had signaled to Tom to take care of the fourth and last
German airman, and guard the important observation plane.

Tom started down with a rush, just as a hungry hawk might swoop upon a
pigeon it had marked for its intended prey.

"I've got to make good!" the young aviator told himself. "I've got to
make good!"

The German pilot saw him coming. He had more than half expected to be