"Simple enough," he answered. "We Allied aviators have a secret system of signals, something like Freemasonry. When we come near another plane that seems to be one of our own, we make a certain dip of our plane. That's like asking for the countersign. If the other fellow's all right he makes a certain signal in return. If he doesn't do it the first time, we try again, because there's always a chance that he hasn't noticed our signal, or is too busy in handling his plane to give the reply. But if after two or three times we don't get the countersign, we know the fellow's a Hun and we open up on him."

"Good stuff!" approved Billy.

"That's what happened this morning," continued d.i.c.k. "This fellow came sailing along as calm and cheeky as you please, and was having a bully time taking pictures of our positions. At least I suppose that is what he was doing, as he evidently wasn't out looking for fight. I thought it wouldn't do any harm to take a look at him, although I saw the machine had French markings. I gave the signal, but of course he couldn't give the countersign. I repeated it three times without getting an answer, and then I pitched into him. That makes the thirteenth that I've brought down."

"Thirteen was an unlucky number for him, all right," remarked Billy.

"How are you fellows getting along?" asked d.i.c.k, stretching himself out on the ground for a brief resting spell. "I notice that you've been right up to your neck in fighting lately."

"Its been pretty hot along this sector," Frank admitted, "though I suppose it's nothing to what it will be after the big German drive gets started. That is if it ever does start. I sometimes think they've given up the idea."

"Don't kid yourself," replied the aviator grimly. "It's coming, all right. If you fellows had been up in the air with me you wouldn't have any doubt about it. The roads back of the German lines are just black with troops. It's like an endless swarm of ants. The trains move along in endless procession and they're packed. Big guns, too, till you can't count them. It seems as if all Germany was on the move.

It's the old invasion of the Huns over again."

"Where do they get them all, I wonder," remarked Billy.

"That's easy," replied Frank bitterly. "They're coming from the Russian front. The breakdown of Russia means a cool million at the very least added to the German troops on the western front."

"That accounts for most of them," agreed d.i.c.k. "Then in addition Germany's combing out her empire to put every available man into service. She's enslaving the Belgians to work in her factories so that German workmen can be sent into the ranks. She's calling up mere boys who ought to be at their schoolbooks. I tell you, boys, Germany's desperate. She's beginning to realize what a fool she was to bring America into the war, and she's going to try to get a decision before we get a big army over here."

"She'll have to get busy mighty soon, then," said Bart, "for Uncle Sam's boys are coming into France by the hundreds of thousands. And those hundreds of thousands will be millions before long."

"Right you are," agreed d.i.c.k. "The jig's up with Germany and she's the only one that doesn't see it. It's fun to see the way she tries to belittle America to her own people. Almost every week she has to change the story. At first she said that America wouldn't fight at all. We were a nation of money grabbers. Then even if we wanted to fight the U-boats would keep us from getting over; Then even if we got over, our troops would be green and run like hares as soon as they caught sight of the veteran Prussian regiments."

The boys looked at each other with a grin.

"We've run, all right," chuckled Billy, "but we've run toward them instead of away from them."

"They thought our marines would run too," laughed Frank, "but do you see what they're calling them now? _Teufelhunden_. They're devil-hounds, all right, and the dachshund yelps when he sees them coming."

"What do you think the Germans will aim for when they do begin their drive?" queried Bart.

"The Allied commanders would give a good deal to know that," smiled d.i.c.k. "Of course the thing the Huns want to do above everything else is to separate and crush the Allied armies. Everything would be easy after that. But if they can't do that, they'll probably make a break for Paris. They figure that if they once got that in their hands the French would be ready to sue for peace. Or they may try to take the Channel Ports, where they'd be in good position to take a hack at England. The only thing that's certain is that the drive is coming and when it does come it's going to be the biggest fight in the history of the world."

"Let Heinie do his worst," said Bart.

"Yes," agreed Frank. "And no matter what he does, he'll have to reckon with Uncle Sam."

CHAPTER VII

IN THE HANDS OF THE HUNS

The last thing that Tom Bradford remembered in the fight that separated him from his comrades was the sight of Frank in a bayonet duel with two Germans. He was trying desperately to get to his friend's side and help him in the unequal combat, when a great blackness seemed to sweep down upon him and he knew nothing more.

When he came to consciousness, he felt himself dragged roughly to his feet and thrust into a group of other prisoners who were being sent to the rear under guard of a squad of German soldiers. He reeled and would have fallen had he not been supported by some of his other companions in misfortune. Then the line was set in motion and he stumbled along dazedly, abused verbally by his guards and prodded with bayonets if he lagged or faltered.

Gradually his head stopped whirling and his brain grew clearer. His face felt wet and sticky, and putting his hand to it he drew his fingers away covered with blood.

He felt his head and found a ragged gash running almost the length of the scalp. It must have bled freely, judging from the weakness he felt and the way his hair was matted and his face smeared. But the blood had congealed now and stopped flowing. He figured from the character of the wound that it had been made by a glancing blow from a rifle.

It was fully dark when the gloomy procession halted at a big barn where the prisoners were counted and pa.s.sed in to stay for the night.

A little later some food was pa.s.sed in to the prisoners, but Tom had no appet.i.te and even if he had been hungry it would have been hard to stomach the piece of dry bread and watery soup that was given him as his portion. So he gave it to others, and sat over in a corner immersed in the gloomy thoughts that came trooping in upon him.

He was a prisoner. And what he had heard of Hun methods, to say nothing of a former brief experience, had left him under no delusion as to what that meant.

What were his comrades Frank, Bart and Billy doing now? Had they come safely through the fight? He was glad at any rate that they were not with him now. Better dead on the field of battle, he thought bitterly, than to be in the hands of the Huns.

But Tom was too young and his vitality too great to give himself up long to despair. He was a prisoner, but what of it? He had been a prisoner before and escaped. To be sure, it was too much to expect to escape by way of the sky as he had before. Lightning seldom strikes twice in the same place. But there might be other ways--there should be other ways. While breath remained in his body he would never cease his efforts to escape. And sustained and inspired by this resolve, he at last fell asleep.

When he awoke in the morning, his strength had in large measure returned to him. His head was still a little giddy but his appet.i.te was returning. Still he looked askance at the meagre and unpalatable breakfast brought in by the guards.

"Don't be too squeamish, kid," a fellow prisoner advised him, as he saw the look on the young soldier's face. "Take what's given you, even if it isn't fit for Christians. You'll get weak soon enough. Keep strong as long as you can."

There was sound sense in this even with the woeful prophecy and Tom, though with many inward protests, followed the well-meant advice.

Bad as it was, the food did him good, and he was feeling in fairly good condition when, a little later, he was summoned before a German lieutenant to be examined.

That worthy was seated before a table spread with papers, and as Tom entered or rather was pushed into his presence he compressed his beetling black brows and turned upon the prisoner with the face of a thundercloud.

But if he expected Tom to wilt before his frowning glance he was disappointed. There was no trace of swagger or bravado when Tom faced his inquisitor. But there was self-respect and quiet resolution that refused to quail before anyone to whom fate for the moment had given the upper hand.

The officer spoke English in a stiff and precise way so that an interpreter was dispensed with, and the examination proceeded.

"What is your name?" the lieutenant asked.

Tom told him.

"Your nationality?"

"American."

The officer snorted.

"There is no such thing as American," he said contemptuously. "You are just a jumble of different races."

Tom said nothing.

"What is your regiment?" the officer continued.

There was no answer.

"Did you hear me?" repeated the lieutenant impatiently. "What is your regiment?"

"I cannot tell," answered Tom.