Eight members of the squadron had remained in Cantigny, and these now took to the air—two biplanes and four light monoplanes. Both Bob and Jourdin were in single-seaters this time; little craft in which the pilot must trust to speed and dexterity of handling for his defense. Bob’s heart beat high with hope and confidence as he rose from the field into the bright morning air. They were pointed south for Montdidier, and in ten minutes’ flight the monoplanes had outstripped their heavier comrades. Bob carefully examined his guns and everything within reach in the cockpit. His little plane was flying beautifully; the rhythmic pulse of the engine told him all was in perfect order, and a world of glorious opportunity opened again before him. The last days in the hospital had filled him with restless longing. His efforts in Lucy’s behalf were for the time being thwarted, and for that very reason he must put in good work to-day against the Boches.

Jourdin flew right ahead of him and Larry Eaton was in a third monoplane at his side. In twenty minutes they had neared Montdidier and, above the hot fire from the German trenches, there came swiftly into view the battle in the air. Bob had taken part in several fierce engagements and had grown familiar with the wild thrill that comes with plunging into conflict at thousands of feet above the earth. But, as the little reinforcing squadron drew nearer to the city, he realized that this fight was the greatest he had ever seen.

The air was so filled with planes whirling hither and thither, in furious attack or swift retreat, and the noise of the nearest propellers made such a volume of sound that he could make but a vague guess at the numbers engaged. Gathered together into squadrons, or pursuing each one his enemy independently, the airplanes were fighting in and out among the clouds above the whole of Montdidier and far beyond the city. Bob’s thoughts got no further than this in his momentary confusion, when, from a group a few hundred yards in front, a German Albatross scout darted toward him.

He needed no more than this to restore his coolness and determination. He saw the black crosses on the little plane’s silvery wings, and the wide muzzle of the machine gun, into which the German was fitting a belt of ammunition. His own gun was already loaded. The two weapons crashed out together, the bullets spattering over both moving targets; then each swooped lightly out of range to maneuver again for the advantage. Bob’s tactics were different now when no heavy metal body protected him. His Nieuport could not withstand the hail of bullets that Jourdin’s battle-plane had received in the fight above Argenton, and to use his guns he must swing his whole machine into range. He glanced quickly over the cockpit and saw that the fire from the trenches was too distant to be dangerous. He was flying at just nine thousand feet. The next instant his enemy came up from below him, trying for a shot at the tail of his machine. Bob dropped in a spin, then paused to discharge a stream of bullets on the German’s flank. His enemy dodged, but failed to return the fire. Bob guessed why. His gun was jammed. The German ran away northward, Bob following. The two machines were fairly matched in speed. Another German, scenting danger for his comrade in the escaping plane, made northward too. A third plane followed, and as Bob turned his head to see if this last were friend or foe, the pilot’s hand was raised in greeting, and Larry Eaton signaled with a quick gesture that the second German was his quarry.

Bob nodded agreement and, putting on speed, flew after his retreating foe. He was soon making a hundred miles an hour and the summer air, thin and cold at this height, cut sharply against his face and made welcome the protection of his leather coat and helmet. The German was speeding too, in spite of having to clean and reload his guns. In another moment he dived so suddenly that Bob flashed right over the spot where he had been, as his enemy mounted in a climbing turn directly underneath. Bob passed too swiftly to receive a close hit, but the German managed to deliver a broadside which cut holes in Bob’s left plane and sent bullets whizzing against the cockpit and about his head. Now Bob was in front, his enemy following. Not liking this new arrangement, Bob himself dived, circled up at terrific speed, and fired a burst at his pursuer as the latter was grasping his stick for a plunge. For a second Bob thought he had downed his foe, for the German plane wavered and one wing tilted as though the shots had fatally injured it. But the next moment the plane righted itself. The sudden turn the pilot made in seeking to escape the broadside had caused his machine to veer to one side. The wing was cut by bullets, but not more than Bob’s own. Before Bob could bring his gun to bear again upon his shaken enemy, the German darted upward at lightning speed and vanished in a soft white cloud.

Bob hovered, reloaded his guns and, picking up his binoculars, looked around for Larry and the antagonist he had pursued. How had Jourdin ever managed, he wondered, to send down the forty-eight enemy planes the famous ace had to his credit. It seemed to Bob sometimes as though the winged fighters were almost invincible. His best efforts, when he flew alone, were usually rewarded by seeing his enemy elude him uninjured.

A cloud lay right beneath him, but as he peered down, searching for the other planes, it floated by, leaving a clear view of the distant earth below. To Bob’s astonishment he discovered that he was over ChÂteau-Plessis. There, off to his right, were the wide meadows so familiar to his eyes. Directly beneath was the town itself, looking half-ruined on the side nearest the meadows, but growing less damaged toward the centre. His surprise once over at the distance he had covered from Montdidier, his feeling was one of keen regret. His father and Lucy would see the fight above their heads and suffer all the pain of suspense and uncertainty. Their conquerors would give them no news of the battle unless they could announce a German victory. For as these thoughts flashed through Bob’s mind he saw that this minor fight was growing into a battle.

From the cloud beneath him darted up two German planes, after one of which Larry Eaton’s Nieuport, with its red, white and blue emblems, closely followed. The other German was engaged in a duel with a second American plane, which now appeared behind it, and their loops and spirals left Bob at a loss for the moment to see which had the advantage. His hand was on his control to fly to Larry’s aid, for the foe at that instant had turned upon his pursuer. But some good fortune prompting him to glance upward, Bob saw his old enemy descending on him from the shelter of the cloud-bank. The German opened fire, and Bob made a climbing turn to elude him before attempting any offensive. From his height of some fifty feet above his antagonist he saw the German copying his tactics and rising swiftly to get into range. Bob planned a little stratagem. He wanted above all things to get rid of this pursuer, for with the tail of his eye he saw that the fighters below were engaged in deadly struggle.

As the German rose above him, Bob hovered uncertainly, firing at his enemy from an ineffectual distance, while the latter, contemptuous of these scattering bullets, flew nearer on a higher level, and prepared to pounce. Bob left off firing, gave a swift touch to his responsive motor, and rose like lightning to the other side of his adversary. The German snatched at his port machine gun, but in that second Bob’s deadly broadside had riddled his left wing and torn the fabric to rags. The wire supports cut loose left the wing sagging and powerless. Bob was so close he saw the pilot’s look of furious despair. He saw, too, that even at this moment when his machine wavered to fall, the German’s hand was on his trigger. Bob dropped in a tail-spin as the gun crashed out. A hundred feet down he paused, hovering, and glanced over the cockpit. His enemy’s descent had been quicker than his. He saw the helpless German machine fall to earth among the streets of ChÂteau-Plessis.

The next moment he had darted to the aid of the three Allied planes who were now engaged by six Germans. Three of these last had risen from the trenches in front of ChÂteau-Plessis. Bob saw with joy that Jourdin was fighting near Larry Eaton’s side. The second American was a veteran of the Lafayette squadron. “We have a good chance,” Bob thought with rising confidence. At the same time he saw the face of the German pilot, who was gracefully maneuvering his monoplane for a shot on Jourdin’s flank. Von Arnheim! Bob sent his plane speeding forward, his determination roused as never before, his eyes on the German’s every movement as Von Arnheim sought with incredible nimbleness to throw Jourdin off his guard.

Meanwhile, in ChÂteau-Plessis, the friends of the Allies were watching the fight with desperate interest. The planes were too high to be clearly seen without glasses, and every pair of French or American binoculars had been confiscated. Colonel Gordon’s eagerness had led him out into the garden, his longest walk since his illness, and Lucy glanced anxiously at his pale face from time to time, as side by side they watched the distant planes dart back and forth against the bright blue sky. It was torment to see the fighters’ swift movements without being able to distinguish friend from enemy or even to guess at the progress of the battle. When Bob’s antagonist fell Lucy hid her eyes in horror and dismay. She clung to her father’s arm in panting silence, for words were useless. He knew no more than she whether it was Ally or German, or even Bob himself, who had fallen. The little group gathered around them shifted back and forth in hopeless efforts to get a better sight of the combatants. Only the German officers at Headquarters knew who was winning, and they were not likely to send any news of a reassuring sort to the American hospital.

At Lucy’s entreaty, Elizabeth had gone on a vain search for information. Vain at least so far as getting any accurate news was concerned, for Elizabeth dared not question any one higher in rank than a non-commissioned officer, and these were not supplied with glasses and knew scarcely more than she. The little crowd in the square, among which she paused, was alive with excited speculation, animated or cast down each moment by alternate hopes and fears. Pro-German hopes and fears this time, for most of the crowd, at least the noisiest part of it, was made up of German soldiers. All those off duty or convalescent at the hospitals were there, and Elizabeth soon found an acquaintance.

“Good-day, Sergeant Vogel,” she said politely to a burly, broad-shouldered German who stood staring upward at her side. “We are winning, likely enough, I suppose. I can’t tell though, from here.”

The Sergeant looked down from the sky with a short laugh. “To be sure you can’t, Frau. No more can I. All I know is that one of the birds fell just now. I hope with all my heart it brought a Yankee down.”

“Where did it fall?” asked Elizabeth, cold with apprehension. Bob’s smiling young face flashed before her eyes, and it was hard for her to listen calmly to the Sergeant’s reply.

“Off toward the eastern part of the town. It was some enemy, be sure of that. I can guess at the shape of our planes well enough to see that we far outnumber them.”

Elizabeth dared not show her agitation, nor continue her inquiries. Only a few days past she had questioned this same man about the German soldier who was Armand de la Tour, until he wondered at her idle curiosity. She had learned that Michelle’s brother succeeded in getting away undiscovered, but her unusual inquisitiveness had excited some surprise. While she hesitated now whether to go off by herself and try to stumble on some news, or to return to console Lucy as best she could, a soldier came up and murmured something in Sergeant Vogel’s ear. The message was not a welcome one. The German’s eyebrows and mustaches bristled in an angry frown. His face flushed red and his jaw closed sharply. All the good-humor had left his face, but Elizabeth hazarded a timid question:

“What is it, Sergeant? May I hear the news?”

“No!” snapped the German. “Can’t you bottle up your curiosity for a moment? Am I to answer your questions all day?”

Elizabeth guessed that he was only venting his ill-humor on the nearest object, and waited unresentfully in silence. The Sergeant raised his eyes again to the sky, where the airplanes still swooped and circled, and the frown and flush gradually left his face. In a moment Elizabeth spoke gently once more.

“I should be so much obliged to you, Sergeant, for a little news. One good turn deserves another. Don’t you remember how often I supplied you the best bread and sausage from my nephew’s shop? You and Karl were pretty good cronies then.”

The German laughed his short laugh again. The recollections Elizabeth called up were pleasant ones. “Well, well, Frau, I see there’s no peace until I tell you.” He stooped close to her ear and spoke in a gruff whisper. “It was a German plane that fell. The pilot was killed. Keep your mouth shut, now!” he added sharply. “I tell you a bit of news for friendship’s sake, but it’s not the sort to spread about. Our men are none too cheerful lately as it is. A lot of grumbling dogs!”

Elizabeth sadly shook her head, with a look of silent grief and disappointment. It was not all affected, either, for beneath her genuine joy that the unfortunate pilot was not Bob, and that she could bring relief to Lucy’s anxiety, her heart ached at the death of her young countryman. With all her honest soul Elizabeth longed for the Kaiser’s bloody tyranny to be overthrown, but sometimes she wondered despairingly if there would be any Germans left to enjoy the blessings of peace.

Eager to return to Lucy, she made her way quickly through the crowd, and across the square to the hospital garden. Lucy and her father were still standing there, gazing up at the sky. Colonel Gordon rested his arm against the broken gatepost, but, weary as he was, neither Lucy nor Major Greyson could persuade him to go in. Elizabeth went up to them and as Lucy’s anxious eyes met hers, she said in her soft, quick voice:

“It was not Mr. Bob who fell, dear Miss Lucy—nor any American.” Her voice sank still lower as she added, “A German it was, but nothing say of it to any one.”

The two faces before her lighted as though a cloud were lifted from them. “Oh, Elizabeth, thank you!” breathed Lucy from the depths of her grateful heart. “I knew you’d——” Her words broke off in a quick gasp. Roused by the stir about her she had again glanced upward. Another airplane was falling to the earth, whirling down through the clear air on one helpless broken wing.

The battle had begun to shift south again, toward Cantigny, but, in the hot fighting of the past few minutes, Bob failed to notice that they were no longer directly above ChÂteau-Plessis. Jourdin had sent down one of his antagonists, and Bob tried hard to do as much for Von Arnheim, but without success. Jourdin still eluding him, the German turned all his attention to the young American. Never until that moment had Bob fully realized Von Arnheim’s skill and coolness. His own movements, lightning-like as they had seemed before, became suddenly slow and clumsy, while a swift and deadly fire enveloped him from the enemy swooping and dodging alongside.

He himself dodged, fell in a tail-spin, then rose again, vainly seeking to throw Von Arnheim off or get him within range. The stream of bullets from his own machine gun scarcely touched the little plane that circled like a gnat around him, never an instant still. Bob’s heart began to pound in his ears, and his cool brain grew furious and desperate. Unable to endure the galling fire which was cutting his wings and beating against the body of his plane, he determined to risk a rush at his pursuer. Suddenly the nose of a monoplane shot up in front of him. As Bob’s tense fingers felt for the trigger of his second gun the stranger pilot gave a shout, and Larry Eaton’s eyes looked into his. Never was help more welcome. Bob’s courage soared again, and while Larry pumped bullets on Von Arnheim’s flank, Bob climbed swiftly, and, once above his enemy, at last turned an effective fire upon him.

Von Arnheim dodged in a graceful circle, turning this time upon Larry with undiminished vigor. Bob saw that his friend was no more able than himself to withstand these tactics. He shot downward to Larry’s help, and, diving between the two planes, delivered a heavy burst of fire on Von Arnheim’s right, just as the German had got into range to make an end of his new adversary.

Larry’s blue eyes flashed acknowledgment to Bob, as Von Arnheim, staggered for the moment, sank in a tail-spin, seeking a chance to reload. Bob did not follow him. With frantic haste he reloaded both his guns, feeling cautiously of his left wrist, where a bullet had grazed it. A German Fokker had swooped down upon Larry, and Bob, after one quick glance about him at the airplanes darting in and out among the light clouds, made for the new enemy’s left. A German Albatross scout was flying toward Larry on the other side, and Bob thought to engage the Fokker himself, and give Larry a chance for a fair fight with the newcomer. At that instant he heard the familiar crackling of machine-gun fire directly above, and, looking up, saw Von Arnheim coming down upon him.

He dropped, his spin becoming a spiral dive that sent him down a thousand feet, but still the German followed. Bob darted to one side and rose at top speed, looking for the friendly shelter of a cloud. There was none near enough to give him a moment’s respite. As he maneuvered his starboard gun into range, resolved to retreat no longer, Von Arnheim, rushing upon him from a slightly higher level, drew his pistol and leveled it at Bob’s head. In that breath of time a monoplane, swooping like a hawk from above, came between Von Arnheim and his prey with a mastery equal to the German’s own. Jourdin’s fire struck Von Arnheim full on the flank—impossible to withstand. He dropped like a plummet, avoiding new attack by a zigzag fall, as Bob and Jourdin closely followed. The three were almost on a level. Jourdin glanced keenly in Bob’s direction, for Bob’s left wing was badly riddled. At that instant Von Arnheim, quick as a flash of light, leaned forward and discharged his pistol at the Frenchman’s breast.

Bob did not know that he cried out. Overcome with grief and horror, he saw Jourdin fall helplessly against his gun. The little monoplane, abandoned by its pilot, reeled and tilted. Bob flung his arm up to shut out the sight, but at the sound of a propeller near at hand he raised his head and looked dizzily about him. With one hand he felt blindly for his trigger. Jourdin had fallen, and close to Bob Von Arnheim was circling into range, the light of triumph in his eyes. Bob’s troubled glance had hardly rested on his enemy when Larry Eaton, stealing up from below, opened a burst of fire upon Von Arnheim’s rear. In that instant, without Larry’s interference, Bob would have unresistingly met Jourdin’s fate. But as the German turned on his new aggressor, the despair that had held Bob paralyzed gave way before a new emotion. Never in his life had he felt anything like the spirit of indomitable purpose that surged now within him. His face grew hard and pale, his eyes flashed like Von Arnheim’s own, and with a swift, light touch on his control stick, he flew after Larry in the German’s wake.

One thing Bob was sure of. He would send Von Arnheim down or fall himself. Both of them could not survive this battle. He thought coolly and quickly now, every sense on guard as he stole up behind his enemy. The German was beating off Larry’s pursuit with steady firing. Larry would try to rush closer in another moment, Bob thought, planning how to take his friend’s place in the duel. For Larry’s plane was not flying well. It veered too much at a turn of the rudder, and Bob looked at the wings to see if they were badly torn. As he looked, Larry’s plane began to sway and the propeller’s speed slackened. Engine trouble, Bob guessed now, and gave a shout of warning. The next moment the engine stopped dead, and Larry, abandoning his attack, was forced to volplane down as best he could for a landing.

Von Arnheim followed, firing at the helpless plane in its swift descent, but before he had dived a hundred feet Bob was beside him. All sense of his own danger had vanished as completely as though he were invulnerable to Von Arnheim’s skill. With careful aim he fired full at the body of the German plane. It quivered and tilted while Von Arnheim, oblivious to his damaged left wing, returned the attack by a withering blast of fire. The bullets sprayed Bob’s little monoplane. His riddled right wing began to bend and sag. The instruments on the board in front of him were smashed to atoms. Von Arnheim had dodged again and was behind him. Bob flashed a glance at his own wings and thought he could risk one loop. Without lessening his speed he turned completely over, and darting up behind Von Arnheim in a swift and skilful maneuver discharged his port gun, from a distance of a few yards, on the right wing and rudder.

With a throb of glorious triumph he saw the German plane pitch forward. Unable to recover, it fluttered a moment, vainly struggling for life, then plunged down toward the green fields below. Bob leaned out and watched it crash against the earth. Then, panting a little, he rubbed one hand across his forehead and looked about him. He had left the other fighters behind. No new enemy threatened him, and fortunately, for his plane would hardly answer the rudder. The right wing was a mass of flying ribbons, and the cockpit was dented and hammered in by countless bullets. Even protected by its metal sides, he could not think how he had escaped unhurt. One hand was bleeding, but the wound was only a trifle. He began cautiously flying down, fearing to put his damaged wings to the pressure of high speed. His one thought now was to reach Jourdin’s side. He might have fallen in some lonely spot where no one would come to him. By the look of the country beneath him, Bob guessed that he was somewhere near Cantigny. He picked out a level bit of ground and glided safely to the grass.

As he landed he caught sight of a fallen airplane in an adjoining field. A little group of four or five men were gathered about it. Von Arnheim, Bob thought, not realizing that his course had been confined to a small circle in the past few moments. He climbed out and began running toward the group in search of information. Passing through a line of shell-torn poplars he came upon Larry Eaton’s plane resting at the edge of the field. The next minute Larry himself left the others and came toward him. Bob looked again at the wrecked monoplane beyond, and saw that it was Jourdin’s.

Larry slowly nodded in answer to Bob’s sad, questioning glance. “He’s dead, Bob. He was dead before he fell. He had no other injury when they lifted him out.”

In silence Bob drew near and stood by the body of his friend where it lay upon the grass. They had taken off his helmet, and Jourdin’s fine face looked calm and peaceful in its utter repose. The officers and mechanicians gathered about him gave tribute of their grief in downcast looks and gloomy silence. At Bob’s approach a flash of satisfaction lighted their eyes for the swift retribution he had meted to Von Arnheim. The officer beside him murmured some words of congratulation and sympathy, but Bob could only nod in answer. He was not ashamed of the tears that rushed to his eyes as he knelt bareheaded at Jourdin’s side. He thought of the fight above Argenton, and of the words that had come to his mind that day, as Jourdin stood looking at the ruined countryside:

“We may go under, but not in vain——”

Not in vain, while America was free and had men left to fight. At that moment, as never before, Bob felt his consecration to the cause that he upheld. Jourdin’s faith and deathless courage became part of him.

As he rose unsteadily to his feet, Larry Eaton flung an arm about his shoulders and drew him a little to one side.

“You’re wounded, Bob,” he said anxiously. “Let me look.”

“It’s nothing,” said Bob, showing the hand he had concealed in his flying-coat. “I don’t even feel it.”

“It’s bleeding, all the same. I’ll tie it up for you.”

Under Larry’s commonplace words Bob felt such genuine friendly sympathy that he was dumbly grateful. Larry was just a boy like himself who had left Yale to join the army when Bob had left West Point. Their thoughts and feelings had much in common. He held out his hand and let his companion dress the slight wound that caused the bleeding.

“Von Arnheim—is he dead, too?” he asked presently. “Where did he come down?”

“On the other side of that little slope. He was killed by the fall. Bob, you did a wonderful day’s work! Think what Von Arnheim’s loss means!”

“We paid dearly enough for it,” said Bob sombrely.

On the day following the battle Captain Jourdin was buried behind Cantigny, in a part of his well-loved Picardy that the Boches had never reached. Officers, men and townspeople followed the body covered with the Tricolor; his brother aviators flew overhead along his path, and every honor that love and homage could devise was paid him.

At almost the same hour the body of Von Arnheim received honorable burial within the Allied lines. Above his grave were fired the three volleys which are the privilege of every soldier. Under Major Kitteredge’s directions Larry Eaton flew over the German lines and dropped a message announcing their ace’s death.

It was the 21st of June, one month after the capture of ChÂteau-Plessis.