young as they were. And, as a matter of fact, nearly all the aviators are young. It takes young nerves for the work.

"Here's one letter, anyhow!" observed Tom, as he tore open a missive that was handed to him. "It's from dad, too! I hope he's all right. He must have been when he wrote this, for it's in his own hand."

"I've got one from my mother," said Jack. "They're all well," he went on, quickly scanning the epistle. "But they haven't received our last letters."

"That isn't surprising," said Tom. "The mail service is fierce. But I suppose it can't be helped. We're lucky to get these. And say!" he exclaimed excitedly, as he read on in his letter. "Here's news all right—great news!"

Jack looked at his chum. Tom's face was flushed. The news seemed to be pleasurable.

Jack was about to ask what it was, when he saw a messenger running from the telephone office. This was the main office, or, at least, one of the main offices, in that section, and official, as well as general, news was sometimes sent over the wire.

The man was waving a slip of paper over his head, and he was calling out something in French.

"What's he saying?" asked Jack.

"Something about good news," answered Tom. "I didn't get it all. Let's go over and find out. It's good news all right," he went on. "See! they're cheering."

"More news," murmured Jack. "And you have some, too?"

"I should say so! Things surely are happening this morning! Come on!" and Tom set off on a run.

CHAPTER II

ANXIOUS DAYS

While Tom and Jack were hastening toward the man who seemed to have received some message, telephone, telegraph or wireless, from the headquarters of this particular aviation section, a throng of the aviators, their mechanicians, and various helpers, had surrounded the messenger and were eagerly listening to what he had to say.

"I wonder what it can be, Tom," murmured Jack, as the two fairly ran over the field.

Those of you who have read the two preceding volumes of this series will remember Tom Raymond and Jack Parmly. As related in the first book, "Air Service Boys Flying for France; or The Young Heroes of the Lafayette Escadrille," the youths had, some time previously, gone to a United States aviation school in Virginia, their native state, and there had learned the rudiments of managing various craft of the air. Tom's father was an inventor of note, and had perfected a stabilizer for an aeroplane that was considered very valuable, so much so that a German spy stole one of the documents relating to the patent.

It was Tom's effort to get possession of this paper that led him and, incidentally, his chum Jack into many adventures. From their homes in Bridgeton, Virginia, they eventually reached France and were admitted into that world-famed company—the Lafayette Escadrille. Putting themselves under the tuition of the skilled French pilots, the Air Service boys forged rapidly to the front in their careers.

It was while on a flight one day that they attacked a man in a motor car, who seemed to be acting suspiciously along the sector to which our heroes were assigned, and they pursued him, believing him to be a German spy.

Their surmise proved correct, for the man, who was hurt when his machine got beyond control, was none other than Adolph Tuessig, the German who had vainly tried to buy Mr. Raymond's stabilizer from him, and who had, later, stolen the paper.

In our second volume, entitled, "Air Service Boys Over the Enemy's Lines; or The German Spy's Secret," Tom and Jack found further adventures. On their way to England, whence they had gone to France, they had met on the steamer a girl named Bessie Gleason. She was in the company of Carl Potzfeldt. The girl seemed much afraid of him, though he was her guardian, said to have been so named by Mrs. Gleason, a distant relative of his. Mrs. Gleason had been on the ill-fated Lusitania, and it was related by Potzfeldt, for purposes of his own, that Bessie's mother had been drowned. Moreover, he declared that before she died she had given him charge of Bessie.

Tom and Jack, the latter especially, grew very fond of Bessie, but there seemed to be a mystery about her and something strange in her fear of her guardian.

When the two young men reached England, they lost sight, for a time, of their fellow passengers, but they were destined to meet them again under strange circumstances.

During one of their flights they landed near a lonely house behind the German lines. They were traveling in a Caudron, which contained them both, and on investigating the building after dark they found, to their surprise, that Bessie and her mother were kept there, prisoners of Carl Potzfeldt, who was a German spy.

Bessie and her mother were rescued and then departed for Paris, the latter to engage in Red Cross work, and the boys, remaining with their fellow aviators, longed for the time when they might see their friends once more.

But they had enlisted to help make the world safe for democracy, and they intended to stay until the task was finished. Over a year had elapsed since the sensational rescue of Bessie and her mother. The United States had entered the war and the Air Service boys were thinking that soon they might be able to join an American aviation service in France.

"What is it? What has happened?" Tom demanded of one of the aviators on the outskirts of the throng about the messenger. "Have we won a victory over the Germans?"

"No, but we're going to," was the answer. "Oh, boy! It's great! We're in it now sure! Hurray!"

"In it? What do you mean?" asked Jack.

"I mean that Uncle Sam has at last stepped over the line! He's sure enough on the side of the Allies now, and no mistake."

"You mean—" cried Tom.

"I mean," answered Ralph Nelson, another American aviator, "that the United States has made a big success of the Liberty Bonds loan and is going to send a million soldiers over here as soon as possible! Say, isn't that great?"

"Great? I should say so!" fairly yelled Tom. "Shake!" he cried, and he and his chum and everybody else shook hands with every one whose palm they could reach. And there were resounding claps on the back, and wild dances around the green grass, even the French joining in. No not that word "even," for the French, with their exuberance of spirit, really started the joy-making.

To the brave men, who, with the British, had so long endured the brunt of the terrible blows of the Huns alone, the efforts of the United States of America meant much, though it was realized that it would be some time before Uncle Sam could make his blows really tell, even though an Expeditionary Force was already in the field.

"Say, this is the best news ever!" said Jack to Tom, when quiet, in a measure, had been restored. "It's immense!"

"You said something, old man! It's almost as good news as if you had come in and told me that you had downed a whole squadron of German aircraft."

"I wish I could, Tom. But we'll do our share. Shouldn't wonder, before the day is out, but what we'd get orders to go up and see what we can spot. But I'm almost forgetting. You had some news of your own."

"Yes, I have. And now I have a chance to finish reading dad's letter."

"But first you can tell me what the special news is, can't you?" asked Jack. "That is, unless you think it will be too much for me to stand all in one day—your news and that about Uncle Sam's success in raising funds and troops."

"Oh, I guess you can stand it," said Tom with a smile. "It's this. Dad is coming over!"

"He is? To fight?"

"Well, no, not actively. He's a little too old for that, I'm afraid, though he's anxious enough. But he left for Paris the day he wrote this. He ought to be here now, for he would, most likely, get off ahead of the mail, which, sometimes, seems slower than molasses."

"That's right!" exclaimed Jack, with such