CHAPTER XI

THE SIGNALS

"Say, where'd you hear all this?" demanded Roger. "Is it straight goods?"

"Sure it is," answered Jimmy. "Talk of it all over. I got it from one of the orderlies at brigade headquarters."

"Just what was it?" Bob asked.

"Iss der German brutes by us goin' to come again?" asked Iggy.

"If they do I hope they don't find us as unprepared as the bunch was last night," remarked Jimmy, gloomily enough. "It was a bad piece of business. But it wouldn't have happened if the Huns hadn't known some of the reserves had been pulled away from that sector."

"Were they?" was Bob's question.

"Yes," answered Jimmy, who had acquired considerable of this disquieting information. "Our side was planning a big raid, but not in this immediate neighborhood. On that account the headquarters staff sent for some of our reserves. They were taken off quietly enough, and it was thought the Germans wouldn't get wise to the fact. But they did, and they took a jump over, and got away with it, worse luck!"

"And you say it was because of treachery on the part of someone on our side?" asked Roger.

"That's the story," admitted his chum. "You'll hear the talk as soon as you circulate around a bit. It's a rotten shame, that's what it is!"

"But how did anyone from our side get over to the German lines without being shot--unless he took the part of a spy and put on a German uniform?" asked Bob.

"They didn't go over--they sent signals," went on Jimmy. "And those signals are what gave away the weak spot in our lines."

"Signals!" exclaimed his chums. "What kind?"

"Different kinds," replied the young sergeant. "Last night there were light signals, but, of course, signals could be sent by day also, using smoke balls. You know we have a new machine for that."

"I didn't know it," admitted Roger. "What is it?"

"Well, I saw one up at the signal corps headquarters the other day. It looked like a big soup kettle with a stove pipe sticking out the top, and there were levers on the sides. I asked one of the fellows how it worked, and he showed me.

"Of course it's easy enough to make different colored fire signals at night," went on Jimmy. "You've all seen them, even on Fourth of July. But it isn't so easy to signal by smoke in the daytime--or, rather, it wasn't until this machine was invented. Before that they could send up puffs of white or dark smoke, just as the Indians used to signal from one mountain top to the other.

"But one of the signal corps men invented this 'smoke kettle,' as I'll call it. The smoke clouds can be made of almost any color--red, green or yellow. And there are white ones, too. It's all done by chemicals. When you pull one lever it sends a certain mixture of chemicals into the caldron. They form a ball of dense, colored smoke. A puff of compressed air sends the ball out up through the 'stove pipe,' as I'll call it, and it sails up into the air, keeping its round shape, like a cloud.

"I suppose they have some code, or combination, by which a certain number of smoke balls of a stated color sent up at definite intervals mean something to the man who sees 'em."

"Did the traitors send up signals that way?" asked Bob.

"I'm not certain of that. All I know is that the smoke balls by day and the colored fires by night are the means used by the regular signal corps. Whether the traitors took a leaf from their book, or stole one of the caldron machines and used it, I don't know. But it gave our weakness away all right, and we got in Dutch."

"Rotten work!" exclaimed Roger, and the others agreed with him.

"Dose craters should of be put in de smoke ball and dropped by a bomb yet!" declared Iggy.

"That's right, old scout!" exclaimed Jimmy. "Only don't call 'em 'craters,' Iggy, lad. You're thinking of a shell-hole. 'Traitors' is the word," and he spelled it.

"I of thankfulness to you am," said Iggy. "English, she is of mos' queer talk to learn, but I will on keep."

"Only way to do!" said Jimmy.

The information he had given his chums they soon verified by hearing the talk in and out of the trenches of the disaster of the previous night. That the American plans had been betrayed by someone within the Allied lines was evident. In no other way could the Germans have known that the supporting reserves had been withdrawn. And because of the demoralization caused by the success of the German raid it was impossible, for the time being, to go on with the plans of using the massed reserves, as had been hoped.

That afternoon, following mess, when Roger and Bob were on their way to the rear with a message to headquarters they met Captain Dickerson. He was in company with other officers attached to the secret service, and as the captain, who had once been suspected by the boys of being a spy, passed them he acknowledged their salute and paused to speak to them.

"I was wondering if we had any trace of them, sir?" said Bob, suggestively.

"Trace of whom?" inquired the captain with a good-natured smile.

"The fellows who sent signals from our lines and brought on the raid last night," said Roger.

"Oh, so you've heard that story, too?" asked the captain.

"Isn't it true?"

"Well, I'm not going to deny or affirm it," said Captain Dickerson, with a half smile. "But you boys seem to have luck in digging up mysterious matters, so if you hear of any bunch of fellows acting in a queer way or having certain chemicals in their possession you might let me know."

"We will, sir!" promised Bob, and Roger nodded his assent.

"I'll say this much," went on the captain. "The secret service department is working hard to locate the place where the signals came from, and trying to discover who sent them--if any were sent." The secret service official added this in order to be in conformity with his former statement of not admitting anything.

"We'll be on the watch as best we can," promised Roger.

Captain Dickerson walked on with other officers from the secret service department of the army, and Bob and Roger regarded each other with serious eyes.

"There's more to this than appears," declared Roger.

"I believe you," agreed his chum.

And in the days that followed they learned this more fully. For the location of a number of American batteries and machine gun nests was, in some manner, disclosed to the enemy. In consequence there was a shelling of these spots by the Germans, and considerable damage was done.

In one instance a battery had been carefully planted in a certain place and carefully camouflaged. It was hoped, after all the guns were in place, to open up a fusillade on a strong German position and carry it. This would have removed a menace from the American lines--a sort of small angle from which a raking fire was often sent.

But the night before the battery was to have opened it was almost completely destroyed by German shell fire. And the shells came with such accuracy, falling through the camouflaged screen, that it could not be doubted the exact location of the cannon was known to the Huns.

"But if the signals can be seen by the Germans, why can't they be seen by our men?" asked Roger. "And if they are seen, the location ought to be easy to come at."

"I don't know what the reason is," replied Jimmy, "but I know they haven't discovered the traitors as yet. It's getting serious, let me tell you!"

"I should say so!" agreed Bob.

It was about a week after the discovery that secret signals were aiding the Germans that Jimmy, coming back from a visit to the hospital where he had called to see a wounded chum, startled his friends by saying:

"I've heard from Franz!"

"No!" cried Bob incredulously.

"Yes," asserted Jimmy emphatically. "Listen while I tell you!"