"That is odd," he mused. "New activity there this morning. Maybe the Boches have planned an ammunition dump at that point. That is one for the bombers."

Thus time passed. Archie was busy dodging his dangerous namesakes, while Carleton focused his entire attention on gathering material for his report.

Carleton did not watch the movements below, however, with more care than Archie watched the sky on all sides for signs of enemy air-craft. The American machine had been so long inside the enemy lines that a German fighting plane might be expected at any moment. At last a Boche plane did make its appearance, a mere brown speck, at first, far ahead. Archie's signal to Carleton that trouble was ahead was conveyed by giving the machine a slight rock as he started to climb. Not much time was allowed for maneuvering. Carleton lost no time in placing a disk on his Lewis gun, and as the German approached, both observers opened up with a salvo. It was all over in a second. Firing point blank, in that fraction of time spent in passing, both had missed.

The excitement of that brief encounter, a mere matter of seconds as the two swift planes swept out of each other's range, was hardly past when the rattle of a machine-gun nearby and the zipp! zipp! as the bullets tore their way through the canvas, told of another Boche machine at hand. Neither Archie nor Carleton could see it. Carleton unbuckled the strap that held him in his seat, rose, and looked over the top plane.

There, just above and well out of range, was an enemy fighting plane. The machine had apparently dropped from the clouds above, and with great good fortune gained an ideal position. Before Archie could swing his "bus" around so that Carleton could get his Lewis gun to work on the Boche another salvo came from the enemy machine-gun.

That belt of cartridges found its mark. Both Carleton and Archie were hit, the former badly. The young officer dropped back into his seat. Archie saw that the lad had sufficient presence of mind to hastily buckle his belt round his waist again, then, his right shoulder numb, he dived steeply, bringing his plane up and straightening it out after a sheer drop of a thousand feet.

The German machine tail-dropped alter the American one, but by a stroke of good luck the enemy pilot seemed to have some difficulty in righting. When Archie headed for home the Boche flier was far below.

Carleton had become unconscious. Archie's head began to swim. His right arm became stiff, and the blood from a wound in the shoulder trickled down his sleeve. He dared not try to stop the bleeding, and decided to trust to luck and make for home as fast as he could. Periodically he became dizzy and faint, and once, when he thought he was going to lose consciousness, he was roused by an anti-aircraft shell that burst but a few feet from one of his wing tips. He managed to dodge about and tried a half circle to get out of range of the guns below.

Archie felt cold and hot by turns. Then his arm became painful. The pain was all that made him keep consciousness, he thought afterward. At last his own lines were passed. He felt a strange weakness, and began to lose interest. Carleton's inert body swayed to one side, and called Archie's attention to the fact that he was custodian of another life, as well as his own, if life was still in Carleton's body. Archie felt, somehow, that Carleton was not dead. That thought keyed him up to still greater effort. He throttled his engine and started downward, the warmer airs welcome as he came lower. At last he was in home air. A final decision to buck up and hang on was necessary to urge his weak muscles to act. He swayed in his seat. His eyes closed and his grasp on the levers slackened. Again he saw that senseless form strapped in the observer's seat. Poor Carleton. He had been hard hit. Nothing for it but to land him as gently and as safely as possible. Will power overcame the growing weakness and inertia for one more struggle against the darkness that threatened his consciousness, and Archie, striving with every element of his being against falling forward insensible, threw back his elevator and made a good landing.

As the machine came to rest the mechanics ran up to it and found both observer and pilot apparently lifeless in their seats. Willing hands soon had the two young men out of the machine and in the orderly tent under the eye of the doctor. Carleton was the first to regain consciousness. He was sorely wounded, a machine-gun bullet having struck him in the neck and another in the leg. Archie's wound was not so bad, but the hard fight to keep going and bring Carleton and himself back home safely had told on his nervous system. At last he opened his eyes, and smiled to hear his C.O., who was standing beside him, say: "Carleton says you both got it well on the Boche side of the line, and that you must have done wonders to get away and get home. We won't forget your pluck, young fellow. Now let them take you away and patch you up as soon as they can."