Numerically the Hun planes, were superior to the American fleet of airships that quickly rose to oppose them. That probably accounted for fact that the Germans did not turn tail and scurry back beyond the protection of their own anti-aircraft guns and batteries. For it was seldom, if ever, they went into a fight when the odds were against them.

On came the Fokkers and Gothas, the black iron crosses painted on the wings of the machines standing out in bold relief in the clear air. The sun glinted on the red craft which were in the lead, and besides Tom, who headed for one of these, a French ace darted down from a height to engage the red planes.

“See if you can plug him when I put you near enough!” cried Tom to his observer, who had the reputation of being a good shot with the Lewis gun. Practice with the machine weapons in aeroplanes had been going on, for some time among the new American aviators. “Let him have a good dose!” cried Tom. “If you miss him, then I'll try!”

Of course Tom had to shut off the engine when he said this, as no voice could have been heard above the roaring of the powerful motor. But when he had given his companion these instructions and had ascertained, by a glance over his shoulder, that the lad understood for he nodded his head, Tom again turned on the gasoline, and the propeller, that had been revolving by momentum and because of the pressure of air against it, took up its speed again.

Straight for the red machine rushed Tom, and a quick glance told him that his companion was ready with the gun. The weapon to be worked by the latter was mounted so that it could be aimed independently of the aeroplane. Tom also had a gun in front of him, but it was fixed and could be aimed only by pointing the whole craft. Once this was done Tom could operate the weapon with one hand, steering with the other, and, at times, with his feet and knees.

There came several sharp pops near Tom's head, and he knew these were machine bullets from the Hun aviator's gun, breaking through the tightly stretched linen fabric of the wings of his own plane.

“Let him have it before he plugs us!” cried Tom to his companion, though of course the latter could not hear a word. An instant later Tom heard the Lewis gun behind him firing, and he saw several tracer bullets strike the Hun machine. But they were not near the aviator himself, and did no material damage.

“Guess he's too nervous to shoot straight,” reasoned Tom. “I'll have to try my own gun,” he decided.

Tom noticed that the Hun was climbing up, trying to get into a position above the American plane, which is always an advantage. And the air service boy knew he must not let this happen. Quickly he shifted the rudder and began to climb himself. But he was at a disadvantage as his machine carried double, while the red plane had only one man in it, an ace beyond a doubt.

“I've got to get him now or never!” thought Tom. Once more he shifted his direction, and then, as he had his gun aimed just where he wanted it, he pressed the lever and a burst of bullets shot out and fairly riddled the red plane. It seemed to stop for an instant in the air, and then, quivering, turned and went down in a nose dive, spinning around.

“No fake about that!” mused Tom, as he leaned over and looked down from the height. “He's done for!”

And so, the Hun was, for he crashed to the ground behind the American lines. The incident did not affect Tom Raymond greatly. It was not his first killing. But when he, glanced back toward his companion, he saw that the other was shrinking back as if in horror.

“He'll get over that soon enough. All he has to do is to think of what the Huns have done—crucifying men and babies—to make his heart hard,” thought Tom.

Whether his companion did this or not, did not disclose itself, but the fact remains that when Tom flew off to engage another Hun machine the lad back of him rose to the occasion and shot so well that Fritz veered off and flew back over his own lines, wounded and with his craft barely able to fly.

Not all the American machines fared as well as this, however. Jack was in poor luck. The first burst of bullets from the German he engaged punctured his gasoline tank, and he was obliged to coast back to his own aerodrome to get another machine, if possible. He was also hit once in the leg, the wound being painful though not dangerous. He received first aid treatment and wanted to get back into the fight, but this was not allowed, and he had to watch the battle from the ground.

The fight was fast and stubborn, and in the end the American forces won, for at a signal from the remaining red plane, which seemed to bear a charmed existence, as it did not appear to be hit, the others remaining of the Hun forces, turned tail and scooted back to safety.

But they had left a toll of five machines sent crashing to earth, four of them each containing two men. The leading French ace was killed, a severe loss to the Allied forces, and three of the American machines were damaged and their operators severely wounded, though with a chance of recovery. By American machines is meant those assigned for use to Pershing's forces, though the craft used up to that time were of French or English make. The real American machines came into use a little later.

“Well, I think we can call it one to our credit,” said Tom, as he rejoined Jack after the battle.

“Yes. But you had all the luck!” complained his chum. “It went against me, and the lad I took up. It—”

“Never mind; it'll be your turn next,” replied Tom, consolingly.

And so the new American aviators received their baptism of fire, and, to their credit, longed for more.

More credit was really due the American forces than would be indicated by the mere citation of the losses inflicted on the German side in this first air battle. For many of the American fighters were “green,” while not one of the Huns, as was learned later, but what had several Allied machines to his score. And so there was rejoicing in General Pershing's camp, even though it was mingled with sorrow at the losses inflicted.

Busy days followed, Tom and Jack were in the air much of the time. And when they were not flying they were delivering talks to new students, who were constantly arriving. They found time once to run into Paris on their day of leave, to see Bessie and Nellie, and they went on a little picnic together, which was as jolly as such an affair could be in the midst of the terrible war. Nellie had received no word of her missing brother, and Jack and Tom had no encouragement for her.

Then came more hard work at camp, and another battle of the air in which the American forces more than equaled matters, for they fairly demolished a German plane squadron, sending ten of the machines crashing to earth and the others back over the Hun lines, more or less damaged. That was a great day. And, as a sort of reward for their work, Tom and Jack were given three days' leave. At first they thought to spend them in Paris, but, learning that neither Bessie nor her mother nor Nellie could leave their Red Cross work to join them, the two lads made other arrangements.

“Let's go back and see the fellows in the Lafayette Escadrille,” suggested Tom.

“All right,” agreed Jack.

And thither they went.

That they were welcomed need not be said. It was comparatively quiet on this sector just then, though there had, a few days before, been a great battle with victory perching on the Allied banners. The air conflicts, too, had been desperate, and many a brave man of the French, English or American fliers had met his death. But toll had been taken of the Boches—ample toll, too.

The first inquiry Tom and Jack had made on their arrival at their former aerodrome had been for news of Harry Leroy, but none had been received.

It was when Tom and Jack were about to conclude their visit to their former comrades of the air that an incident occurred which made a great change in their lives. One sunny afternoon there suddenly appeared, a mere speck in the blue, a single aeroplane.

“Some one of your men must have gone a long way over Heinie's lines,” remarked Jack to one of the French officers.

“He is not one of our men. Either they were all back long ago or they will not come back until after the war—if ever. That is a Hun machine.”

“What is he doing—challenging to single combat?” asked Tom, as the lone plane came on steadily.

“No,” answered the officer, after a look through his glasses. “I think he brings some messages. We sent some to the Germans yesterday, and I think this is a return courtesy. We will wait and see.”

Nearer and nearer came the German plane. Soon it was circling around the French camp. Hundreds came out to watch, for now the object of the lone aviator was apparent. He contemplated no raid. It was to drop news of captured, or dead, Allied airmen.

Then, as Tom, and the others watched, a little package was seen to fall from the hovering aeroplane. It landed on the roof of one of the hangars, bounced off and was picked up by an orderly, who presented it to the commanding officer.

Quickly and eagerly it was opened. It contained some personal belongings of Allied airmen who had been missing for the past week. Some of them, the message from the German lines said, had been killed by their falls after being shot down, and it was stated that they had been decently buried. Others were wounded and in hospitals.

“No word from Harry,” said Tom, sadly, as the last of the relics from the dead and the living were gone over.

“Well, I guess we may as well give him up,” added Jack. “But we can avenge him. That's all we have left, now.”

“Yes,” agreed Tom. “If we only—?”

A cry from some of those watching the German plane interrupted him. The two air service boys looked up. Another small object was falling. It landed with a thud, almost at the feet of Tom and Jack, and the latter picked it up.

It was an aviator's glove; and as Jack held it up a note dropped out. Quickly it was read, and the import of it was given to all in a simultaneous shout of joy from Tom and Jack.

“It's word from Harry Leroy! Word from Harry at last!”