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+Project Gutenberg's Air Service Boys Over The Rhine, by Charles Amory Beach
+
+This eBook is for the use of anyone anywhere at no cost and with
+almost no restrictions whatsoever.  You may copy it, give it away or
+re-use it under the terms of the Project Gutenberg License included
+with this eBook or online at www.gutenberg.org
+
+
+Title: Air Service Boys Over The Rhine
+       Fighting Above The Clouds
+
+Author: Charles Amory Beach
+
+Illustrator: Robert Gaston Herbert
+
+Release Date: October 3, 2010 [EBook #33834]
+
+Language: English
+
+Character set encoding: ISO-8859-1
+
+*** START OF THIS PROJECT GUTENBERG EBOOK AIR SERVICE BOYS OVER THE RHINE ***
+
+
+
+
+Produced by Bruce Albrecht, Mary Meehan and the Online
+Distributed Proofreading Team at http://www.pgdp.net
+
+
+
+
+
+
+
+
+
+                      AIR SERVICE BOYS OVER THE RHINE
+
+                       OR, FIGHTING ABOVE THE CLOUDS
+
+                           BY CHARLES AMORY BEACH
+
+            AUTHOR OF "AIR SERVICE BOYS FLYING FOR FRANCE,"
+            "AIR SERVICE BOYS OVER THE ENEMY'S LINES," ETC.
+
+
+    ILLUSTRATED BY
+    ROBERT GASTON HERBERT
+
+    THE SAALFIELD PUBLISHING CO.
+    AKRON, OHIO       NEW YORK
+
+    MADE IN U.S.A.
+
+    COPYRIGHT, 1919, BY
+    GEORGE SULLY & COMPANY
+
+
+[Illustration: BLOWING UP THE GERMAN MUNITION FACTORY.]
+
+
+
+
+CONTENTS
+
+
+I DOUBLE NEWS
+
+II ANXIOUS DAYS
+
+III ON TO PARIS
+
+IV SUSPICIONS
+
+V THE BOMBARDMENT OF PARIS
+
+VI THE RUE LAFAYETTE RUINS
+
+VII TOM'S FATHER
+
+VIII WHERE IS MR. RAYMOND?
+
+IX VARIOUS THEORIES
+
+X THE "DUD"
+
+XI A MONSTER CANNON
+
+XII FOR PERILOUS SERVICE
+
+XIII THE SPY
+
+XIV WITH COMRADES AGAIN
+
+XV THE PICKED SQUADRON
+
+XVI MISSING
+
+XVII SEEKING THE GUN
+
+XVIII A CLOUD BATTLE
+
+XIX QUEER LIGHTS
+
+XX THE BIG GUN
+
+XXI DEVASTATING FIRE
+
+XXII OVER THE RHINE
+
+XXIII OFF FOR GERMANY
+
+XXIV PRISONERS
+
+XXV THE ESCAPE
+
+
+
+
+AIR SERVICE BOYS OVER THE RHINE
+
+
+
+
+CHAPTER I
+
+DOUBLE NEWS
+
+
+"Here they come back, Tom!"
+
+"Yes, I see them coming. Can you count them yet? Don't tell me any of
+our boys are missing!" and the speaker, one of two young men, wearing
+the uniform of the Lafayette Escadrille, who were standing near the
+hangars of the aviation field "somewhere in France," gazed earnestly up
+toward the blue sky that was dotted with fleecy, white clouds.
+
+There were other dots also, dots which meant much to the trained eyes of
+Tom Raymond and Jack Parmly, for the dots increased in size, like
+oncoming birds. But they were not birds. Or rather, they were human
+birds.
+
+The specks in the sky were Caudrons. A small aerial fleet was returning
+from a night raid over the German ammunition dumps and troop centers,
+and the anxiety of the watching young men was as to whether or not all
+the airmen, among whom were numbered some of Uncle Sam's boys, had
+returned in safety. Too many times they did not--that is not all--for
+the Hun anti-aircraft guns found their marks with deadly precision at
+times.
+
+The Caudrons appeared larger as they neared the landing field, and Tom
+and Jack, raising their binoculars, scanned the ranks--for all the world
+like a flock of wild geese--to see if they could determine who of their
+friends, if any, were missing.
+
+"How do you make it, Tom?" asked Jack, after an anxious pause.
+
+"I'm not sure, but I can count only eight."
+
+"That's what I make it. And ten of 'em went out last night, didn't
+they?"
+
+"So I heard. And if only eight come back it means that at least four of
+our airmen have either been killed or captured."
+
+"One fate is almost as bad as the other, where you have to be captured
+by the Boches," murmured Jack. "They're just what their name
+indicates--beasts!"
+
+"You said something!" came heartily from Tom. "And yet, to the credit of
+airmen in general, let it be said that the German aviators treat their
+fellow, prisoners better than the Hun infantrymen do."
+
+"So I've heard. Well, here's hoping neither of us, nor any more of our
+friends, falls over the German lines. But look, Tom!" and Jack pointed
+excitedly. "Are my eyes seeing things, or is that another Caudron
+looming up there, the last in the line? Take a look and tell me. I don't
+want to hope too much, yet maybe we have lost only one, and not two."
+
+Tom changed the focus of his powerful glasses slightly and peered in the
+direction indicated by his chum. Then he remarked, with the binoculars
+still at his eyes:
+
+"Yes, that's another of our machines! But she's coming in slowly. Must
+have been hit a couple of times."
+
+"She's lucky, then, to get back at all. But let's go over and hear what
+the news is. I hope they blew up a lot of the Huns last night."
+
+"Same here!"
+
+The aircraft were near enough now for the throbbing of their big motors
+to be heard, and Tom and Jack, each an officer now because of gallant
+work, hurried across the landing field.
+
+It was early morning, and they had come, after a night's rest, to report
+for duty with others of the brave Americans who, during the neutrality
+of this country in the great conflict, went to France as individuals,
+some to serve as ambulance drivers, others to become aviators.
+
+The Caudron is the name given to one type of heavy French aeroplane
+carrying two or more persons and tons of explosive bombs.
+
+An air raid on the German lines by a fleet of these machines had been
+planned. It had been timed for an early hour of the night, but a mist
+coming up just as the squadron of heavy machines, each with two men and
+a ton or more of explosives, was ready to set out, the hour had been
+changed. So it was not until after midnight that the start had been
+made.
+
+And now the boys were coming back--that is all who were able to return.
+One machine was missing. At least, that was the assumption of Tom and
+Jack, for they could count but nine where there should have been ten.
+And of the nine one was coming back so slowly as to indicate trouble.
+
+One by one the machines, which ordinarily came back before daybreak,
+landed, and the pilot and the observer of each climbed clumsily down
+from their cramped seats. They were stiff with cold, in spite of the
+fur-lined garments they wore--garments that turned them, for the moment,
+into animated Teddy bears, or the likeness of Eskimos.
+
+Their faces were worn and haggard, for the strain of an airship bombing
+raid is terrific. But they were quiet and self-possessed as they walked
+stiffly across the field to make a report.
+
+"Any luck?" asked Tom, of one he knew; a Frenchman noted for his skill
+and daring.
+
+"The best, _mon ami_," he replied with a smile--a weary smile. "We gave
+Fritz a dose of bitter medicine last night."
+
+"And he gave us a little in return," sadly added his companion. "Quarre
+and Blas--" he shrugged his shoulders, and Tom and Jack knew what it
+meant.
+
+They were the men in the missing machine, the Caudron that had not come
+back.
+
+"Did you see what happened?" asked Jack.
+
+Picard, to whom Tom had first spoken, answered briefly.
+
+"They caught them full in the glare of a searchlight and let them have
+it. We saw them fall. There didn't seem to be any hope."
+
+"But the battery that did the firing--it is no more," added De Porry,
+the companion of Picard. "The bombs that Quarre and Blas carried went
+down like lead, right on top of the Hun guns. They are no more, those
+guns and those who served."
+
+"It was a retributive vengeance," murmured Picard.
+
+Then they passed on, and others, landing, also went to make their
+reports.
+
+Some of them had reached their objectives, and had dropped the bombs on
+the German positions in spite of the withering fire poured upward at
+them. Others had failed. There is always a certain percentage of
+failures in a night bombing raid. And some were unable to say with
+certainty what damage they had caused.
+
+The last slowly flying machine came to a landing finally, and there was
+a rush on the part of the other aviators to see what had happened. When
+Tom and Jack saw a limp form being lifted out, and heard murmurs of
+admiration for the pilot who had brought his machine back with a
+crippled engine, they realized what had happened.
+
+The two brave men had fulfilled their mission; they had released their
+bombs over an important German factory, and had the terrible
+satisfaction of seeing it go up in flames. But on their return they had
+been caught in a cross fire, and the observer, who was making his first
+trip of this kind, had been instantly killed.
+
+The engine had been damaged, and the pilot slightly wounded, but he had
+stuck to his controls and had brought the machine back.
+
+There was a little cheer for him, and a silent prayer for his brave
+companion, and then the night men, having made their reports, and having
+divested themselves of their fur garments, went to rest.
+
+"Well, what's on the programme for to-day, Tom?" asked Jack, as they
+turned back toward the hangars where they had their headquarters with
+others of their companions in the Lafayette Escadrille and with some of
+the French birdmen.
+
+"I don't know what they have on for us. We'll have to wait until the
+orders come in. I was wondering if we would have time to go and see if
+there's any mail for us."
+
+"I think so. Let's go ask the captain."
+
+They had, of course, reported officially when they came on duty, and now
+they went again to their commanding officer, to ask if they might go a
+short distance to the rear, where an improvised post-office had been set
+up for the flying men.
+
+"Certainly, messieurs," replied the French captain, when Tom proffered
+the request for himself and his chum. "Go, by all means." He spoke in
+French, a good mastery of which had been acquired by our heroes since
+their advent into the great war. "Your orders have not yet arrived, but
+hold yourselves in readiness. Fritz is doubtless smarting under the dose
+we gave him last night, and he may retaliate. There is a rumor that we
+may go after some of his sausages, and I may need you for that."
+
+"Does he mean our rations have gone short, and that we'll have to go
+collecting bolognas?" innocently asked a young American, who had lately
+joined.
+
+"No," laughed Tom. "We call the German observation balloons 'sausages.'
+And sometimes, when they send up too many of them, to get observations
+and spoil our plans for an offensive, we raid them. It's difficult work,
+for we have to take them unawares or they'll haul them down. We
+generally go in a double squadron for this work. The heavy Caudrons
+screen the movements of the little Nieuports, and these latter, each
+with a single man in it, fire phosphorus bullets at the gas bags of the
+German sausages.
+
+"These phosphorus bullets get red hot from the friction of the air, and
+set the gas envelope aglow. That starts the hydrogen gas to going
+and--good-night to Mr. Fritz unless he can drop in his parachute. A raid
+on the sausages is full of excitement, but it means a lot of
+preparation, for if there has any rain or dew fallen in the night the
+gas bags will be so damp that they can't be set on fire, and the raid is
+off."
+
+"Say, you know a lot about this business, don't you?" asked the young
+fellow who had put the question.
+
+"Nobody knows a _lot_ about it," replied Jack. "Just as soon as he does
+he gets killed, or something happens to him. We're just learning--that's
+all."
+
+"Well, I wish I knew as much," observed the other enviously.
+
+Tom and Jack walked on toward the post-office, being in rather a hurry
+to see if there was any mail for them, and to get back to their stations
+in case their services were needed.
+
+As they went along they were greeted by friends, of whom they had many,
+for they had made names for themselves, 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 energy that Tom asked:
+
+"What's the matter? Haven't you heard from Bessie lately?"
+
+"Oh--that!" murmured Jack, but Tom noticed that his friend blushed under
+his coat of tan. "Go on," Jack said, a moment later, "tell me about your
+father. Is the French government going to give him a big order for his
+stabilizer, now that we got that paper away from that sneak of a
+Tuessig?"
+
+"Well, I guess dad's trip here has something to do with his aeroplane
+device, but he hints in his letter about something else. He said he
+didn't want to write too much for fear a spy might get hold of the
+information. But you know my father is an expert on ordnance matters and
+big guns, as well as in other lines of fighting."
+
+"That's so, Tom. He certainly is a wonder when it comes to inventing
+things. But what do you suppose his new mission is?"
+
+"I can't quite guess. But it is for the service of the Allies."
+
+"And you say he's on his way to Paris now?"
+
+"He ought to be there by this time," Tom answered. "I'm going to see if
+I can't get permission to send a message through, and have an answer
+from dad. Maybe he might get out here to see us."
+
+"Or we could go in and meet him."
+
+"Not for a week. You know we just came back from leave, and we won't be
+over our tour of duty for seven days more. But I can't wait that long
+without some word. I'm going to see what I can find out."
+
+Tom and Jack, like all the other American fliers, were in high favor
+with the French officers. In fact every aviator of the Allied nations,
+no matter how humble his rank, is treated by his superiors almost as an
+equal. There is not that line of demarcation noticed in other branches
+of the service. To be an aviator places one, especially in England and
+France, in a special class. All regard him as a hero who is taking
+terrible risks for the safety of the other fighters.
+
+So Tom readily received permission to send a message to the hotel in
+Paris mentioned by his father as the place where Mr. Raymond would stay.
+And then Tom had nothing to do but wait for an answer.
+
+Nothing to do? No, there was plenty. Both Tom and Jack had to hold
+themselves in readiness for instant service. They might be sent out on a
+bombing expedition at night in the big heavy machines, slow of flight
+but comparatively safe from attack by other aircraft.
+
+They might have the coveted honor of being selected to go out in the
+swift, single Nieuports to engage in combat with some Hun flier. To
+become an "ace"--that is a birdman who, flying alone, has disposed of
+five enemies--is the highest desire of an aviator.
+
+Tom and Jack, eager and ambitious, were hoping for this.
+
+Again, in the course of the day's work, they might be selected to go up
+in the big bi-motored Caudrons for reconnoissance work. This is
+dangerous and hard. The machines carry a wireless apparatus, over which
+word is sent back to headquarters concerning what may be observed of the
+enemy's defenses, or a possible offensive.
+
+Often the machines go beyond the range of their necessarily limited
+wireless, and have to send back messages by carrier pigeons which are
+carried on the craft.
+
+By far the most dangerous work, however, is that of "_relage_" or fire
+control. This means that two men go up in a big machine that carries a
+large equipment. Their craft is heavy and unwieldy, and has such a
+spread of wing surface that it is not easily turned, and if attacked by
+a German Fokker has little chance of escape. A machine gun is carried
+for defense.
+
+It is a function of those in the machine to send word back to the
+battery officers of the effect of the shots they are firing, that the
+elevation and range may be corrected. And those who go out on "_relage_"
+work are in danger not only from the fire of the enemy's batteries, but
+often, also, from their own.
+
+Tom and Jack had their share of danger and glory during the week they
+were on duty following the receipt of the two pieces of news. They went
+up together and alone, and once, coming back from a successful trip over
+the enemy's lines, Tom's machine was struck by several missiles. His
+cheek was cut by one, and his metal stability control was severed so
+that his craft started to plunge.
+
+Tom thought it was his end, but he grasped the broken parts of the
+control rod in one hand, and steered with the other, bringing his
+machine down behind his own lines, amid the cheers of his comrades.
+
+"And I'm glad to be back, not only for my sake, but for the sake of the
+machine. She's a beauty, and I'd have hated like anything to set fire to
+her," remarked Tom, after his wound had been dressed.
+
+He referred to the universal practice of all aviators of setting fire to
+their craft if they are brought down within the enemy lines, and are not
+so badly injured as to prevent them from opening the gasoline tank and
+setting a match to it. This is done to prevent the machine, and often
+the valuable papers or photographs carried, from falling into the hands
+of the enemy.
+
+The end of the week came, the last of seven anxious days, and it was
+time for Tom and Jack to be relieved for a rest period. And the days had
+been anxious because Tom had not heard from his father.
+
+"I hope the vessel he was coming on wasn't torpedoed," said Tom to his
+chum. "He's had more than time to get here and send me some word. None
+has come. Jack, I'm worried!" And Tom certainly looked it.
+
+
+
+
+CHAPTER III
+
+ON TO PARIS
+
+
+Those were the days--and they had been preceded by many such--when
+travel across the Atlantic was attended with great risk and uncertainty.
+No one knew when a lurking German submarine might loose a torpedo at a
+ship carrying men, women and children. Many brave and innocent people
+had found watery graves, and perhaps suffered first a ruthless fire from
+the German machine guns, which were even turned on lifeboats! So it was
+no wonder that Tom Raymond was worried about his father.
+
+"It's queer we can't get any word from the authorities in Paris,"
+remarked Jack, as he and his chum were speculating one day on what might
+have happened.
+
+"Yes, and that helps to bother me," Tom admitted. "It isn't as if they
+weren't trying, for the officers here have done all they can. They've
+gotten off my messages, but they say there is no reply to them."
+
+"Then it must mean that your father, if he is in Paris, hasn't received
+them."
+
+"Either that, Jack; or else he doesn't dare reply."
+
+"Why wouldn't he dare to, Tom?"
+
+"Well, I don't know that I can give a good reason. It might be that he
+is on such a secret mission that he doesn't want even to hint about it.
+And yet I can't understand why he doesn't send me at least a message
+that he has arrived safely."
+
+As Tom said this he looked at his chum. The same thought was in the mind
+of each one:
+
+Had Mr. Raymond arrived safely?
+
+That was what stirred Tom's heart. He knew the danger he and Jack had
+run, coming across to do their part in flying for France, and he well
+realized that the Germans might have been more successful in attacking
+the vessel on which his father had sailed, than they had the one which
+had carried Tom and Jack.
+
+"Well, what are we going to do?" asked Jack of his chum. "You know we
+arranged, when we should get our leave, to go back to that pretty little
+French village, which seemed so peaceful after all the noise of battle
+and the roar of the aeroplane engines."
+
+"Yes, I know we planned that," said Tom, reflectively. "But, somehow, I
+feel that I ought to stay here."
+
+"And not take our relief?"
+
+"Oh, no. We'll take that," decided Tom. "We must, in justice to
+ourselves, and those we work with. You know they tell us an airman must
+always be at his best, with muscles and nerves all working together. And
+a certain amount of rest and change are necessary, after a week or so of
+steady flying. So we'll take our rest in order to be in all the better
+shape to trim the Fritzies. But I was thinking of staying right here."
+
+"And not go back into the country?" asked Jack.
+
+Tom shook his head.
+
+"I'd like to stay right here until I get word from my father," he said.
+"He may send a message at any time, and he knows I am stationed here. Of
+course I could send him word that we're having a little vacation, and
+give him our new address.
+
+"But the mails are so mixed up, and the telegraph and telephone systems
+are so rushed, that he might not get it. So I think the best thing will
+be to stay right here where I'll be on hand to get it the moment word
+comes. But don't let me keep you, Jack. You can go, if you want to."
+
+"Say, what do you think I am?" cried his chum. "Where you stick, I
+stick! We'll both wait here for word from your father. I have a sort of
+feeling that he is all right."
+
+"Well, to tell you the truth, I suppose he is. But, at the same time,
+I'm worried. I can't explain it, but I have a sort of sense that he is
+in danger."
+
+"Not if he is in Paris, Tom. The German's haven't gotten within striking
+distance of that city yet, in spite of their boasts--the boasts of the
+Kaiser and of the Crown Prince."
+
+"No, if dad were in Paris I'd feel that he was comparatively safe. But
+first I want to know that he is. And yet, even if he has put up at that
+house in the Rue Lafayette, where he said in his letter he'd stay, there
+may be some danger."
+
+"Danger in Paris? What do you mean, Tom?"
+
+"Well, Paris has been bombed from the air, you know."
+
+"True, Tom. But, say! we've almost come to disregard such mild things as
+that from the Huns, haven't we?"
+
+"Well, we'll just stay right on here," decided Tom. "I don't mean to say
+that we'll stay around our hangar all the while, but we'll keep in
+touch, throughout the day, with the communication headquarters. Dad may
+send a message at any time, and I want to get it as soon as it arrives."
+
+Jack could understand his chum's feelings, and so the Air Service boys,
+who, some time previous, had sought and received permission to go back
+several kilometers into the country for a rest, announced that they
+would stay on at the aerodrome.
+
+Nor did they lack excitement. The place where they were stationed was a
+busy one. For every twenty pilots and observers there are detailed about
+one hundred men as helpers. There are cooks, photographers, mechanics of
+various sorts, telephone, telegraph and wireless operators, orderlies
+and servants.
+
+Of these Tom and Jack had their share, for it is the business of an
+airman to fly and fight, and he does nothing except in that line. He is
+catered to and helped in every possible way when not in the air. He has
+some one to wait on him, to look after his machine, and to attend to his
+hurts, if he is unlucky enough to get any. Of course each flier goes
+over, personally, his own craft, but he has oilers and mechanics to do
+all the detail work.
+
+"Well, there they go!" exclaimed Tom to Jack one morning, the second of
+their "vacation," as they observed a number of "aces" about to go up
+and search above the clouds for some Hun to attack.
+
+"Yes, and I wish I was with them!" said Jack.
+
+"Waiting isn't much fun," agreed his chum. "I'm sure I can't understand
+why dad doesn't send some word. If this keeps up much longer--Say, Jack,
+look at Parla!" he suddenly cried. "What's the matter with him?"
+
+Jack looked. The men, in their machines, had started off to get momentum
+for a rise into the air. But there had been a rain and the ground was
+soft, which kept down the speed. All the pilots seemed to get off in
+fairly good shape except one, Parla by name, who had only recently
+secured the coveted designation of "ace."
+
+And then occurred one of those tragedies of flying. Whether he was
+nervous at taking a flight in such distinguished company, or whether
+something went wrong with Parla's machine never would be known.
+
+He was the last in the line, and as it was rather misty he might have
+been anxious not to lose sight of his companions. He did not take a long
+enough run, and when he reached the end of the field he was not high
+enough to clear the line of hangars that were in front of him.
+
+Some one shouted at him, not stopping to realize that the noise of the
+motor drowned everything else in the ears of the pilot.
+
+The luckless man tried to make a sharp turn, to get out of danger. One
+of his wing tips caught on the canvas tent, or hangar, and in another
+instant there was a crash and a mass of wreckage. From this, a little
+later, poor Parla was carried.
+
+But the others did not stay, for though the shadow of death hovered over
+the Escadrille, the business of war went on.
+
+After three days Tom and Jack could not stand it any longer. They begged
+for permission to go up into the air. It was granted, though officially
+they were still on leave. Ascending together in a Caudron, on a
+photographing assignment, they were attacked by two swift German
+Fokkers.
+
+Tom worked the gun, and to such good effect that he smashed one machine,
+sending it down with a crash, and drove the second off. So other laurels
+were added to those the boys already had.
+
+"If this keeps on we'll be soon wearing the chevrons of sergeants," said
+Jack, as they landed.
+
+"Well, I'd almost give up hope of them to hear from dad," announced
+Tom. "I'm going to see if some word hasn't come."
+
+But there was no message. Still the strange silence continued, and Tom
+and his chum did not know whether Mr. Raymond had reached Paris or not.
+Through his own captain, Tom appealed to the highest authority at the
+Escadrille, asking that a last imploring message be sent to the address
+in the Rue Lafayette.
+
+This was done, and then followed another day of waiting. At last Tom
+said:
+
+"Jack, I can't stand it any longer! This suspense is fierce!"
+
+"But what are you going to do about it?"
+
+"I'm going to Paris! That's what! We'll go there and find my father if
+he has arrived. If he hasn't--well, there is still some hope."
+
+"Go to Paris!" murmured Jack.
+
+"Yes. It's the only place where I can make uncertainty a certainty. Come
+on, we'll go to Paris!"
+
+
+
+
+CHAPTER IV
+
+SUSPICIONS
+
+
+Tom Raymond started across the field toward headquarters. Jack followed,
+but there was a strange look on the latter's face.
+
+"I don't see how you're going to Paris," remarked Jack, at length. "Do
+you mean we're to go in separate machines, or together?"
+
+"Oh, nothing like that!" exclaimed Tom. "We won't go in machines at all.
+We'll go by train, if we can get one, or by motor."
+
+"But you're heading for the Escadrille Headquarters office, and--"
+
+"We've got to get official permission to go," explained Tom. "We can't
+rush off, whenever we like, as we used to go fishing together."
+
+To his captain Tom explained matters more fully than he had done before.
+In effect he related the fact of having received the letter, stating
+that Mr. Raymond had started for Paris, presumably to engage in some
+work for the French government, or at least for the Allies. Whether he
+had arrived or not, and, in the former case, to ascertain why he had
+not sent some word to his son, was the object of Tom's quest.
+
+"I've tried and tried, from this end, to get in touch with him,"
+explained Tom; "but something seems to happen to my messages. I know
+they leave here all right, but after that they are lost. Now I have an
+idea that there is so much going on in Paris--so much necessary war
+work--that the ordinary lines of communication are choked. But if I
+could go to the capital in person I could soon find out whether my
+father was at the address he gave."
+
+"And you want, do you, to go together?" asked the kindly French captain,
+smiling at Tom and Jack.
+
+"We'd like to go," said Tom.
+
+"And go you shall. I will write the necessary order. You have done well,
+and I understand you have some days of leave coming. To them I shall add
+more. But come back to me," he added, as he filled out the pass form.
+"Come back. We need you Americans now more than ever!"
+
+"We'll come back," promised Tom. "All I want to go to Paris for is to
+find out about my father."
+
+"Ah, I envy you," said the captain softly. "Both in the possession of a
+father, who must be proud to have such a son as you, and also because
+you are going to Paris. It is the most beautiful--the most
+wonderful--city in the world. And to think--to think that those
+barbarians would sack her! Ah, it is terrible!" and with a sad nodding
+of his head, following the shaking of an avenging fist toward the German
+lines, he waved Tom and Jack an adieu.
+
+The two Air Service boys lost little time in making their preparations
+to leave for the French capital. They had to get certain passes and
+papers, and they wished to say good-bye to some of their comrades in
+arms. For, more than any other branch of the service, is aviation
+uncertain as to life or death. Tom and Jack well knew that some, perhaps
+many, of those who wished them "_au revoir_," and "_bonne chance_,"
+would not be alive when they returned. And Tom and Jack might not return
+themselves. True, their chances were comparatively good, but the
+fortunes of war are uncertain.
+
+And so, after certain preliminaries, Tom and Jack, their pet machines in
+the hangars, left behind their beloved comrades and were taken by motor
+to the nearest railway station. There they secured their tickets and
+took their places to wait, with what patience they could, their arrival
+in Paris.
+
+The train was well filled with "_permissionnaires_," or soldiers on
+leave for a few days of happiness in the capital, and at certain
+stations, where more got on, the rush was not unlike that at a crowded
+hour in some big city.
+
+"I see something good," remarked Jack, as they sat looking out at the
+scenery, glad, even for a brief moment, to be beyond the horrors of war.
+
+"What?" asked his companion.
+
+"There's a dining-car on this train. We sha'n't starve."
+
+"Good enough, I almost forgot about eating," said Tom. "Now that you
+speak of it, I find I have an appetite."
+
+They ate and felt better; and it was as they were about to leave the
+dining-car to go back to their places, that Jack nudged Tom and
+whispered to him:
+
+"Did you hear what he said?"
+
+"Hear what who said?"
+
+"That man just back of you. Did you have a good look at him?"
+
+"I didn't, but I will have," said Tom, and, waiting a moment so as not
+to cause any suspicion that his act was directed by his chum, Tom turned
+and looked at the person Jack indicated. He beheld a quietly dressed
+man, who seemed to be alone and paying attention to no one, eating his
+lunch.
+
+"Well, what about him?" asked Tom. "I don't see anything remarkable
+about him, except that he's a slow eater. I admit I bolt my food too
+much."
+
+"No, it isn't that," said Jack in a low voice. "But don't you think he
+looks like a German?"
+
+Tom took another casual glance.
+
+"Well, you might find a resemblance if you tried hard," he answered.
+"But I should be more inclined to call him a Dutchman. And when I say
+Dutchman I mean a Hollander."
+
+"I understand," remarked Jack. "But I don't agree with you in thinking
+that he may be from Holland. Of course men of that nationality have a
+right to go and come as they choose, where they can, but I don't believe
+this chap is one."
+
+"Why not?"
+
+"Because I heard him mutter something in German."
+
+"Well, lots of Hollanders can speak German, I have no doubt. I can
+splutter a few words myself, but not enough to hurt me. I began to pick
+up some from the prisoners, after we had that experience with Potzfeldt,
+when we realized that even a little knowledge of the Hun's talk, much as
+we hate him, would be of service. And so you think you heard this fellow
+speak German?" asked Tom, as he pretended to tie his shoe lace, to make
+an excuse for pausing.
+
+"I'm sure I did," said Jack.
+
+"What did he say?"
+
+"Something about wishing he had a plate of _metzel suppe_. Of course I
+don't guarantee that pronunciation, but--"
+
+"Oh, it'll do," said Tom, graciously. "Well, there's nothing very
+suspicious in that, though. I might wish for some _wienerwurst_, but
+that wouldn't make me a German spy."
+
+"No. But take one other thing and you'll have to admit that there is
+some ground for my belief."
+
+"What's the other thing, old top?" asked Tom, in imitation of some
+Englishmen.
+
+"He was making drawings of the railroad line," asserted Jack.
+
+"How do you know?"
+
+"I saw him. He pretended to be looking at the _carte de jour_, and I
+caught a glimpse of a sheet of paper on which he was making certain
+marks. I'm sure he was sketching out something about the railroad, for
+use, maybe, in a future air raid."
+
+"Nonsense!" exclaimed Tom. "As a matter of fact, I don't doubt that the
+German secret agents know every foot of ground in and about Paris. They
+must have maps of this railroad the same as the French have of some of
+Germany's, only you've got to hand it to the Huns! They certainly went
+into this thing well prepared the more discredit to us, in a way. But
+are you sure of what you say, Jack?" he added, after a moment's thought.
+
+"Positive! I'm sure that man is a German spy, masking as a Hollander or
+possibly a Swiss. He's sighing for some of his country's good
+cooking--though that's one of the few good things about it--and he's
+making some sort of a map."
+
+Tom thought over the matter a moment. The man did not appear to notice
+the two chums.
+
+"I'll tell you what we can do," Tom said. "We'll soon be in at the Gare
+de l'Est, and we can tip off some of the officers around there. They can
+follow this fellow, if they think it's worth while."
+
+"Well, I think it's worth while," said Jack. "If that fellow isn't a spy
+I'm a Dutchman!"
+
+As Jack spoke the man looked up and full at the two lads, almost as if
+he had heard the words.
+
+
+
+
+CHAPTER V
+
+THE BOMBARDMENT OF PARIS
+
+
+"There, Jack! what did I tell you? I win! You lose, and it's me for a
+fine dinner at your expense! You lose! Do you hear?"
+
+Tom Raymond, with a hearty laugh, clapped his chum on the shoulder, and
+seemed mirthfully excited over something. As for Jack Parmly he looked
+first at his chuckling comrade and then at the man he suspected of being
+a German spy. The latter, who had glanced keenly at the boys, with
+something akin to anger on his face, now was plainly puzzled.
+
+"Do you understand?" demanded Tom in a loud voice, which attracted the
+attention of many in the car. But a look at the two, showing them to be
+Americans and, therefore, to the French mind, capable of any
+eccentricity, seemed to make matters right. Most of the diners resumed
+their meals.
+
+"See what I mean, Jack?" went on Tom. "You lose! Understand?"
+
+"No, I don't understand," was the low-voiced and somewhat puzzled
+answer.
+
+"Then for the sake of your gasolene tank _pretend_ that you do!"
+fiercely whispered Tom in his chum's ear. "Play up to my game! Don't you
+see that fellow's suspicious of us? He thinks we've been talking about
+him. I win, do you understand?"
+
+"Oh, yes," answered Jack, and then, in a louder tone, intended to allay
+suspicion on the part of the suspect, he added: "You win all right, Tom!
+I'll buy the dinner. I didn't think the train would get in so soon! It's
+one on me all right!"
+
+And then, laughing and talking in seeming carelessness, as though they
+had not a thought in the world but the friendly wager they had made,
+they went back to their coach.
+
+"That was a narrow squeak," observed Tom. "He was getting suspicious all
+right, and in another moment might have made an indignant demand of the
+guard that we cease observing him. It might have made trouble for us.
+We're not members of the secret police, remember."
+
+"Well," remarked Jack, "he might have made trouble for us, but I could
+do the same for him. I'd let fall a hint about the map of the railway he
+was sketching."
+
+"You mean all right, Jack, but I don't believe your plan would work. If
+that fellow really is a German spy, which I doubt, he'd destroy the
+map, if he made one, the moment he thought himself in danger."
+
+"Maybe you're right, Tom," agreed his chum, a bit dubiously. "But I
+certainly think there is something wrong about that man."
+
+"Maybe you think he is Carl Potzfeldt, disguised, Jack."
+
+"No, nothing like that. Though I wouldn't be surprised if he happened to
+be friendly with that sneaking spy. And, speaking of Potzfeldt, Tom,
+though he isn't by any means a pleasant subject, do you know we are soon
+to be in Paris where--"
+
+"Where Bessie and her mother are, you mean. You're right, old chap, I
+haven't forgotten that, and I'll wager one chance for promotion that you
+haven't forgotten it either."
+
+Jack's blush was sufficient answer to his friend.
+
+"I couldn't quite understand what you meant, Tom, by talking so suddenly
+and loudly about you winning and me losing," went on Jack, as they got
+their baggage ready, for the train was about to enter the Paris station.
+
+"That was camouflage, Jack, pure and unadulterated camouflage," answered
+Tom with a laugh. "I had to do something in a hurry to get that fellow's
+gaze off us, or he might have made a scene, and we don't want that. But
+if I had made a wager with you about the time, I'd have won, for here
+we are, right on the dot, which is unusual in these days, I believe."
+
+"You said something, Tom. But what are we going to do about our spy?"
+
+"Well, if you insist that's what he is, I think the best thing would be
+to notify some secret service official. There must be plenty of them
+around the station. Every passenger, before he leaves the station, has
+to have his papers stamped by the military authorities. Then's your
+chance to tip them off about this chap."
+
+"I'll do it, Tom. I'm not going to lose any chances of putting German
+enemies out of the way."
+
+It was about five o'clock when the train pulled into the Gare de l'Est,
+and the passengers, including many soldiers on leave, prepared for the
+joys of Paris. Tom and Jack, proceeding as did the others to the place
+designated for the official stamping of papers, found a chance to tell
+their suspicions to an officer, and to point out the man Jack suspected.
+
+"The matter shall be attended to," said the military official, treating
+the information with the utmost respect, and evidently considering it of
+more importance than Tom imagined would be attached to it. "We are
+greatly indebted to you, not only because you are of our beloved
+aviators, but because you also think to do this for France--to protect
+her from enemies within as well as from those who are without. France
+thanks you, gentlemen!" and the aged officer saluted the two young men
+as though he considered them his equals.
+
+"Well, now that's off our minds we can get down to the real business
+that brought us to Paris," suggested Tom. "And that's to find my
+father--if he's here. After that we can look up Bessie and her mother,
+if you like, Jack."
+
+"Of course I'll be glad to do that, Tom, and I should think that you--"
+
+"Oh, of a surety, yes, as a Frenchman would say. I'll be happy also, to
+see our friends again, but I know Bessie will consider--"
+
+"Oh, drop it, will you?" begged Jack, for he could see that his chum was
+about to start to rally him about the girl.
+
+"Then," went on Tom, "the first thing to do, in my opinion, is to get to
+this address in the Rue Lafayette where dad said he would make his
+headquarters, and see why he hasn't answered any of my messages. When I
+once see him, and know he's all right, I'll feel better."
+
+"Even capable of eating that dinner you claim to have won from me?"
+asked Jack.
+
+"Of course."
+
+The two Air Service boys had the satisfaction of seeing the "tip" they
+gave acted on, for as they left the station they observed the officer
+to whom they had reported, detailing a man in plain clothes, evidently
+one of the secret police, to follow the man they had watched in the
+dining car.
+
+"We can leave the rest to the military," said Tom. "And now let's get to
+where we're going."
+
+"Hadn't we better arrange for hotel accommodations, or to stop at a
+pension?" asked Jack. "You know Paris is crowded now, even in war times,
+and we've got to stay here all night, even if we learn that your father
+hasn't yet arrived."
+
+"That's so," agreed Tom. "Maybe we had better get a place to bunk
+first."
+
+It would not have been an easy task had they not worn the uniforms of
+aviators. But once these were noted, they were welcomed with smiles, and
+though at the first place they applied there was no room, the proprietor
+busied himself to such advantage that the boys were soon settled in a
+big double room with a fine view of a busy section of Paris.
+
+On every side was seen evidence of the joy and satisfaction felt at the
+showing made by the progress of the United States in her war programme.
+
+The stars and stripes were seen floating from many staffs, mingled with
+the tricolor of France and the English union jack. That Uncle Sam had
+at last gotten beyond the bounds of patience with a ruthless and
+sneaking enemy and was making energetic warfare against him was welcome
+news to those who had so long borne the unequal brunt of battle.
+
+"Americans? Ah, everything that I have is yours!" the hotel proprietor
+told Tom and Jack. "You have but to ask. And now come, I will show you
+the way to the cellar."
+
+"But we don't care to see the cellar," remarked Tom in wonder. "No doubt
+it is a very fine one, monsieur," he added in his best French, which was
+nothing to boast of. "No doubt it is most excellent, but we don't care
+for cellars."
+
+"Ah, I know, but it is for protection in case of an air raid that I show
+it to you. It is there we all take shelter. There have been raids, and
+there will be more. It is well to be prepared. It is a well-protected
+cellar."
+
+"Oh, well, that's different," observed Jack. "Come on, Tom, we'd better
+learn the best and quickest route to the basement. No telling when we
+might want to use it."
+
+They descended with the proprietor and saw that he had arranged the
+cellar with a false roof of beams, on top of which were sand bags. In
+case a bomb was dropped on the hotel or in its vicinity the cellar would
+offer almost certain protection.
+
+The boys arranged for a stay of at least a week in Paris, having told
+the proprietor their errand to the capital. By the time they had
+finished their dinner they found it was too late to set out in search of
+Mr. Raymond, as in the changed, war-time Paris little could be done in
+the evening. So Tom and Jack retired to their room and their bed.
+
+"Are you going right to the Rue Lafayette?" asked Jack of his chum, the
+next day.
+
+"Yes, and if we can't get any news of him there we'll appeal to the
+military authorities. I have a letter of introduction to persons high in
+authority from our captain."
+
+The boys hailed a taxicab and gave the chauffeur the necessary
+directions. They were bowling along through the beautiful streets of
+Paris, noting on all sides the warlike scenes, and their thoughts were
+busily occupied, when they suddenly became aware that something had
+happened.
+
+Like a thunderbolt from a clear sky there sounded a terrific explosion,
+and at no great distance. The concussion shook the ground, and they
+could feel the taxicab tremble under the shock, while the chauffeur
+instantly threw on all brakes, making the machine skid dangerously.
+
+"What is it? What's the matter?" yelled Jack.
+
+"Airship raid most likely!" shouted Tom. "Boches are dropping bombs on
+Paris! Oh, where's our cellar, Jack?"
+
+The taxicab driver jumped down and opened the door.
+
+"You had best alight, gentlemen," he said. "You must seek shelter."
+
+"Is it an airship raid?" asked Tom.
+
+"No, there is not an airship in sight. No such alarm has been sounded by
+the police. I fear the bombardment of Paris by the Germans has begun!"
+
+
+
+
+CHAPTER VI
+
+THE RUE LAFAYETTE RUINS
+
+
+Tom Raymond and Jack Parmly alighted from the taxicab more quickly than
+they had gotten in. The chauffeur was anxiously scanning the sky.
+Excited men, women and children were rushing about, and yet it was not
+such excitement as might be caused by the first shelling of the
+beautiful city. It was more, as Tom said afterward, as though the
+populace had been taken by surprise by a new method in the same kind of
+warfare, for an occasional German Zeppelin or a bombing aircraft had,
+before this, dropped explosives. To these the French had become as much
+accustomed as one ever can to such terrible means of attack.
+
+But this was different. There was no sign of a Hun aircraft, and, as the
+chauffeur had said, no police warning had been sounded.
+
+"What is it?" asked Jack.
+
+"It is a bombardment, that is all I know," replied the taxicab driver.
+He spoke in French, a language which the two boys used fairly well,
+though, as has been said, their accent left much to be desired.
+
+"You had best seek shelter until it is over," went on the man. "I shall
+do so myself." He seemed to pause suggestively, and Jack handed him some
+money.
+
+"_Merci_," he murmured, and an instant later was careening down the
+street at full speed.
+
+"He isn't losing any time," said Jack.
+
+"No. And perhaps we hadn't better, either. Where'd that shell fall?"
+asked Tom.
+
+"I don't know, but it must have been somewhere about here, judging by
+the noise. Look, the crowd's over that way," and he pointed to the left.
+
+It was true. Careless of the danger of remaining in the open, men, and
+women, too, as well as some children, were rushing toward the place
+where, undoubtedly, the shell from the German gun had fallen.
+
+"Might as well take it in," suggested Jack. "I don't want to crawl down
+into a cellar or a subway quite yet, even if there's one around here; do
+you?"
+
+"No," answered Tom, "I don't. Go on, I'm with you."
+
+They followed the throng, but could not resist the impulse to gaze
+upward now and then for a possible sight of another shell, which, they
+half hoped, they might observe in time to run for shelter. But of course
+that would have been out of the question. However, quiet succeeded the
+din of the explosion, which had been close to the spot where the taxicab
+had stopped and the boys had alighted.
+
+Following the crowd, Tom and Jack came to a side street, and one look
+down it showed the havoc wrought by the German engine of death. The
+shell, of what kind or calibre could not be even guessed, had fallen on
+top of an establishment where a number of women and girls were employed.
+And many of these had been killed or wounded. There were heart-rending
+scenes, which it is not good to dwell upon. But, even in the terror and
+horror, French efficiency was at the fore.
+
+Ambulances were summoned, a guard was thrown about the building, and the
+work of aiding the injured and tenderly carrying out the dead was begun.
+A vast and excited throng increased in size about the building that had
+been hit and there was much excitement for a time.
+
+Tom and Jack managed to get to a place where they could get a view of
+the havoc wrought to the structure itself, and the first thing that
+impressed them was mentioned by Jack, who said:
+
+"They didn't use a very big shell, or there wouldn't have been such
+comparatively slight material damage done."
+
+"The force was mostly expended inside the building," suggested Tom.
+
+"Even so, if it had been a big shell, the kind they fired at Verdun and
+Liège, there'd be a crater here big enough to put a church in. As it is,
+only the two top stories are wrecked."
+
+"That's right," agreed Tom. "I wonder what sort of explosive they are
+using? Must have been one from a bombing aeroplane."
+
+"No, monsieur," interrupted a _gendarme_ who was standing near. "Pardon,
+for speaking," he went on, with a salute, "but there was no airship
+observed over Paris at all. The shell came out of the clear sky."
+
+"But it couldn't have," insisted Jack, in reply to this policeman. "If
+the Germans are firing on Paris they must have some place from which to
+shoot their gun. Either on the ground or from an airship."
+
+"It was not an airship," insisted the _gendarme_. "Excuse me for
+insisting this to one who is in the air service," and he pointed with
+pride to the uniform the boys wore, "but I have seen several air raids,
+and I know! There was no airship seen, or I would have blown the alarm,"
+and he motioned to his whistle which he carried for that purpose.
+
+"It could have come from an immense airship, so high up as to be beyond
+observation," suggested Jack. "That's possible. Probably the Germans
+didn't want to be bombarded themselves by aircraft guns here, and they
+flew high."
+
+The police officer shook his head. He was not convinced.
+
+"But, man, how else could it be?" asked Tom, in some heat. "The Huns
+have to rest their gun somewhere, and you--Say, Jack!" he suddenly
+exclaimed, his face paling slightly, "you don't suppose they have broken
+through, do you?"
+
+"Through our lines about Paris? Never!" cried the police officer. "They
+shall not pass! Our brave soldiers have said it, and they will maintain
+it. They shall not pass!"
+
+"And yet," mused Tom, as he looked at the rescue work going on, "what
+other explanation is there? It's a bombardment of Paris all right, by
+German shells. If they don't come from an aeroplane, high up, they must
+come--"
+
+His words were drowned by another great concussion, but farther off. The
+ground trembled, but there was no sign of flying debris.
+
+"Another!" cried the _gendarme_. "There goes the gun again!"
+
+"I didn't hear any gun," observed Jack. "What we heard was the explosion
+of the shell. Look up, Tom, and see if there's a Hun plane in sight. If
+there is, pity we haven't our machines right now."
+
+The boys carried, slung over their shoulders, powerful binoculars, and
+with these they swept the sky. Others about them were doing the same. By
+this time the most seriously injured had been carried to the hospitals,
+and the dead had been removed, while those only slightly hurt, as well
+as those in the factory not at all injured, were telling their
+experiences. The second explosion seemed to create great terror.
+
+"There isn't a sign of a hostile plane," said Tom, as he swept the sky
+with his glasses.
+
+"I can't see any either," observed Jack. "And yet--"
+
+There sounded the unmistakable roar of an aircraft's propeller.
+
+"There she is!" cried some one.
+
+But it was one of the first of a series of French planes that had
+hastily ascended to search the heavens for a sight of the supposed
+German craft that had dropped the bombs.
+
+"What a chance we're missing!" murmured Jack.
+
+"Yes," agreed Tom. "But they're going to have some flight before they
+locate that Hun. There isn't so much as a speck in the sky except the
+French craft."
+
+"Let's go and see where that other explosion was," suggested Jack, when
+they had observed several of the French planes scurrying to and fro over
+the city, climbing higher and higher in search of the enemy.
+
+"I'm with you," announced Tom. "I wonder what dad thinks of this?"
+
+"It'll be something new for him," said Jack. "He'll have a good chance
+to see how his stabilizer works, if they're using it on these planes
+here. And maybe he can invent a better one."
+
+"Perhaps," returned Tom. "But, Jack, do you know I'm worried about one
+thing."
+
+"I have more than that on my mind, Tom. There are mighty serious times
+all about us, and it's terrible to think of those poor women and girls
+being killed like rats in a trap. I'd just like to be in my plane, and
+with a full gun, and then have a go at the Hun who did this."
+
+"So would I," agreed Tom, as they made their way out of the crowd and in
+the direction in which many of the populace were hurrying to go to the
+scene of the second explosion. "But, Jack, do you know I shouldn't be
+surprised to learn that the shell was not from an airship at all."
+
+"Where would it be from then?"
+
+"The Germans may have massed such a lot of troops at some point opposite
+the French lines, that they have broken through and have brought up
+some of their heavy guns."
+
+Jack shook his head.
+
+"I don't believe they could do it," he said. "You know the nearest
+German line is about seventy miles from Paris. If they had started to
+break through, and had any success at all, the news would have reached
+here before this. And reinforcements would be on the way. No, it can't
+be. There must be some other explanation."
+
+"But what is it?" asked Tom. "They've got to get nearer than seventy
+miles to bombard Paris. You know that."
+
+"I don't think I really _know_ anything about this war," said Jack
+simply. "So many strange, things have happened, so many old theories
+have been discarded, and so many new things have been done that we don't
+know where we are."
+
+"Well that's true. And yet how could the Germans get near enough to
+bombard Paris without some word of it coming in?"
+
+"I don't know. But the fact remains. Now let's get to where the second
+shell fell. Maybe we can see a fragment of it and--"
+
+Once again the words were interrupted by an explosion. This time it was
+closer and the shock was greater.
+
+"That's the third!" cried Jack.
+
+"Yes," added Tom, looking at his watch, "and it's just half an hour
+since the first one fell. That indicates they're firing every fifteen
+minutes. Jack, there's something weird about this."
+
+"You're right. That last one came rather close, too. I wonder where it
+fell?"
+
+A man, passing them, running in a direction away from the sound of the
+last explosion, heard Jack's question. He paused long enough to say;
+"That shell fell in Rue Lafayette. Several buildings are in ruins. Many
+have been killed! It is terrible!"
+
+"Rue Lafayette!" gasped Jack. "That--"
+
+"That's where my father is supposed to be staying!" exclaimed Tom.
+"Come! We must see what happened!"
+
+
+
+
+CHAPTER VII
+
+TOM'S FATHER
+
+
+With anxious hearts the Air Service boys ran on. There was no need to
+ask their way, for they had but to follow the throng toward the scene of
+the most recent exhibition of the Hun's frightfulness and horror.
+
+As they drew near the Rue Lafayette, where Mr. Raymond had said he
+intended to stay while in Paris, the boys were halted by an officer on
+the outskirts of the throng.
+
+"Pardon, but you may not go farther," he said, courteously enough.
+"There is danger. We are about to sound the alarm so that all may take
+to shelter. The Boches are raiding Paris again."
+
+"We know it," said Tom. "But it is no idle curiosity that takes us on."
+
+"No?" politely questioned the policeman.
+
+"No. I am seeking my father. He wrote to me that he would stop in the
+Rue Lafayette, and I have not heard from him since. I was told that the
+last shell fell in that street."
+
+"It did," assented the officer, "and it demolished two houses and part
+of another. Many were killed and injured."
+
+"Then I must see if my father is among them!" insisted the young
+aviator.
+
+"Pardon, monsieur, it is not possible. I have my instructions, and--"
+
+He stopped, and for the first time seemed to become aware of the
+uniforms worn by Tom and Jack. Then the officer saluted as though proud
+to do it.
+
+"Ah," he murmured. "Of the Lafayette Escadrille! You may go where you
+will. Only I hope it is not into danger," he said, as he drew aside for
+them to pass. "Pardon, I did not at first sense who you were. France
+owes you much, messieurs. Keep your lives save for her!"
+
+"We will," promised Tom, as he hurried on, followed by Jack.
+
+They came to the head of the street they sought, and, looking down it,
+beheld ruins greater than they had seen before. As the officer had said,
+two buildings had been completely demolished, and a third partly so, the
+wreckage of all mingling. And amid these ruins police and soldiers were
+working frantically to get out the injured and remove the dead, of whom
+there was a sad number.
+
+Tom's face was white, but he kept his nerve. He had been through too
+many scenes of horror, had been too near death too often of late, as had
+his chum, to falter now, even though his father might be among those
+buried in the wreckage caused by the German shell.
+
+"Do you know what number your father was to stop at?" asked Jack.
+
+"Yes, I have his letter," Tom answered. "I'm afraid, Jack, it was in one
+of those buildings that have been blown apart."
+
+"No, Tom!"
+
+"I'm afraid so. But, even at that, he may have had a chance for his
+life. He may have been out, or, after all, he may not have arrived yet.
+I'm not going to give up hope until I have to."
+
+"That's the way to talk, old man. I'm with you to the last."
+
+They pressed on, and populace and officers alike gave way before them as
+they saw the uniforms.
+
+"We've got to help!" declared Tom. "We must pitch in, Jack, and lend a
+hand here. The soldiers seem to be in charge. Let's report to the
+commanding officer and offer our services."
+
+"But your father?"
+
+"That's the best way to find him if he's in those ruins. Let us help get
+the unfortunates out. I hope I don't find him, but I must make sure."
+
+Making their way through the press of people, which, under order of the
+police and military authorities, had begun to disperse in some small
+measure, Tom and Jack reported to the officer in charge, giving him
+their names and rank, at the same time showing their papers.
+
+"We want to help," the lads told him.
+
+"And I ask no better," was the quick response. "There are dead and dying
+under that pile. They must be gotten out."
+
+And then began heart-rending scenes. Tom and Jack did valiant work in
+carrying out the dead and dying, in both of which classes were men,
+women and children.
+
+The German beasts were living up to the mark they had set for themselves
+in their war of frightfulness.
+
+Each time a dead or injured man was reached, to be carried out for
+hospital treatment or to have the last sad rites paid him, Tom nerved
+himself to look. But he did not see his father, and some small measure
+of thankfulness surged into his heart. But there were still others
+buried deep under the ruins, and it would be some time before their
+bodies, dead or alive, could be got out.
+
+As the soldiers and police worked, on all sides could be heard
+discussions as to what new form or manner of weapon the Germans were
+using thus to reach Paris. Many inclined to the theory that it was a new
+form of airship, flying so high as to be not only beyond ordinary
+observation, but to be unreachable by the type of planes available at
+Paris.
+
+"If we could only find a piece of the shell we could come nearer to
+guessing what sort of gun fired it," remarked Tom, as the two Air
+Service boys rested a moment from their hard, terrible labors.
+
+"Do you mean if it was dropped from an airship it wouldn't have any
+rifling grooves on it?" asked Jack.
+
+"That's it. A bomb, dropped from an aeroplane, would, very likely, be
+only a sort of round affair, set to explode on contact or by a time
+fuse. But if it was a shell fired from a long-range gun, there might be
+enough of it left, after the explosion, to observe the rifling."
+
+"There isn't a gun with a range long enough to reach Paris from the
+nearest German lines, unless they have broken through," said Jack.
+
+"Well, the last may have happened; though I should think we'd have got
+some word of it in that case. There'd be fierce fighting if the Germans
+tried that, and we'd rush reinforcements out in taxicabs as the Paris
+soldiers went out once before."
+
+"Do you think then," asked Jack, as they went back, after their brief
+respite, to their appalling labors, "that they have a gun long enough
+to fire from their nearest point, which is about seventy miles from this
+city?"
+
+"I don't know what to think," remarked Tom. "It seems like a wild dream
+to speak of a gun that can shoot so far; and yet reality is over-topping
+many wild dreams these days. I'm going to reserve judgment. My chief
+concern now, though of course I'm not going to let it interfere with my
+work, is to find my father. If he should have been in here, Jack--"
+
+Tom did not finish, but his chum knew what he meant, and sympathized
+with his unexpressed fear for the safety of Mr. Raymond.
+
+Digging and delving into the ruins, they brought out the racked and
+maimed bodies, and there was more than one whose eyes were wet with
+tears, while in their hearts wild and justifiable rage was felt at the
+ruthless Germans.
+
+Ten had been killed and nearly twice that number wounded in the third
+shell from the Hun cannon.
+
+From a policeman Tom learned that one of the two buildings that had been
+demolished was the number given by Mr. Raymond as the place he would
+stay.
+
+"The place he picked out may have been full, and he might have gone
+somewhere else," said Tom. "We've got to find out about that, Jack."
+
+"That's right. I should think the best person, or persons, to talk to
+would be the janitors, or '_concierges_,' as they call 'em here."
+
+"I'll do that," responded Tom.
+
+Aided by an army officer, to whom the boys had recommended themselves,
+not only by reason of their rank, but because of their good work in the
+emergency, they found a man who was in charge of all three buildings as
+a renting agent. Fortunately he had his books, which he had saved from
+the wreck.
+
+"You ask for a Monsieur Raymond," he said, as he scanned the begrimed
+pages. "Yes, he was here. It was in the middle building he had a room."
+
+"In the one that was destroyed?" asked Tom, his heart sinking.
+
+"I regret to say it--yes."
+
+"Then I--then it may be all up with poor old dad!" and Tom, with a
+masterful effort, restrained his grief, while Jack gripped his chum's
+hand hard.
+
+
+
+
+CHAPTER VIII
+
+WHERE IS MR. RAYMOND?
+
+
+Tom Raymond, having gone through a hard school since he began flying for
+France, soon recovered almost complete mastery of himself. The first
+shock was severe, but when it was over he was able to think clearly.
+Indeed the faculty of thinking clearly in times of great danger is what
+makes great aviators. For in no other situation is a clear and quick
+brain so urgently needed.
+
+"Well, I'm sure of one thing, Jack," said Tom, as they walked away from
+the fateful ruins. "Of those we helped carry out none was my father. He
+wasn't among the injured or dead."
+
+"I'm sure of that, too. Still we mustn't count too much on it, Tom. I
+don't want you to have false hopes. We must make sure."
+
+"Yes, I'm going to. We'll visit the hospitals and morgues, and talk with
+the military and police authorities. In these war times there is a
+record of everybody and everything kept, so it ought to be easy to trace
+him."
+
+"He arrived all right, that's settled," declared Jack. "The agent's
+record proves that."
+
+"Yes. I'd like to have a further talk with that agent before we set out
+to make other inquiries."
+
+This Tom was able to bring about some time later that day. The agent
+informed the lad that Mr. Raymond, contrary to his expectations, had
+arrived only the day before. Where he had been delayed since arriving in
+Europe was not made clear.
+
+"But was my father in the building at the time the shell struck here?"
+asked Tom. "That's what I want to know."
+
+Of this the man could not be certain. He had seen Mr. Raymond, he said,
+an hour or so before the bombardment, and the inventor was, at that
+time, in his room. Then he had gone out, but whether he had come back
+and was in the house when the shell struck the place, could not be said
+with certainty.
+
+But if he had been in his apartment there was little chance that he had
+been left alive, for the explosion occurred very near his room,
+destroying everything. Tom hoped, later, to find some of his father's
+effects.
+
+"There is just a chance, Jack," said the inventor's son, "that he wasn't
+in his room."
+
+"A good chance, I should say," agreed the other. "Even if he had
+returned to his room, and that's unlikely, he may have run out at the
+sound of the first explosion, to see what it was all about."
+
+"I'm counting on that. If he was out he is probably alive now. But if he
+was in his room--"
+
+"There would be some trace of him," finished Jack.
+
+"And that's what we've got to find."
+
+The police and soldiers were only too willing to assist Tom in his
+search for his father. The ruins, they said, would be carefully gone
+over in an endeavor to get a piece of the German shell to ascertain its
+nature and the kind of gun that fired it. During that search some trace
+might be found of Mr. Raymond.
+
+It did not take long to establish one fact--that the inventor's body was
+not among the dead carried out. Nor was he numbered with the injured in
+the hospitals. Careful records had been kept, and no one at all
+answering to his description had been taken out or cared for.
+
+And yet, of course, there was the nerve-racking possibility that he
+might have been so terribly mutilated that his body was beyond all human
+semblance. The place where his room had been was a mass of splintered
+wood and crumbled masonry. There was none of his effects discernible,
+and Tom did not know what to think.
+
+"We've just got to wait," he said to Jack, late that afternoon, when
+their search of the hospitals and morgues had ended fruitlessly.
+
+Meanwhile the French airmen had been scouring the sky for a sight of the
+German craft that might have released the death-dealing bombs on the
+city. But their success had been nil. Not a Hun had been sighted, and
+one aviator went up nearly four miles in an endeavor to locate a hostile
+craft.
+
+Of course it was possible that a super-machine of the Huns had flown
+higher, but this did not seem feasible.
+
+"There is some other explanation of the bombardment of Paris, I'm sure,"
+said Tom, as he and Jack went to their lodgings. "It will be a surprise,
+too, I'm thinking, and we'll have to make over some of our old ideas and
+accept new ones."
+
+"I believe you're right, Tom. But say, do you remember that fellow we
+saw in the train--the one I thought was a German spy?"
+
+"To be sure I remember him and his _metzel suppe_. What about him? Do
+you see him again?" and Tom looked out into the street from the window
+of their lodging.
+
+"No. I don't see him. But he may have had something to do with shelling
+the city."
+
+"You don't mean he carried a long-range gun in his pocket, do you,
+Jack?" and Tom smiled for the first time since the awful tragedy.
+
+"No, of course not. Still he may have known it was going to happen, and
+have come to observe the effect and report to his beastly masters."
+
+"He'd be foolish to come to Paris and run the chance of being hit by his
+own shells."
+
+"Unless he knew just where they were going to fall," said Jack.
+
+"You have a reason for everything, I see," remarked Tom. "Well, the next
+time we go to headquarters we'll find out what they learned of this
+fellow. You know we started the secret service agents on his trail."
+
+"Yes, I know. Well, I was just sort of wondering if he had anything to
+do with the bombardment of Paris. You've got to look for German spies
+now, even under your bed at night."
+
+The boys felt they could do nothing more that day toward finding Mr.
+Raymond. A more detailed and careful search of the ruins might reveal
+something. Until this was accomplished nothing could be done.
+
+They ate a late supper, without much in the way of appetites, it must be
+confessed, and then went out in the streets of Paris. There seemed to be
+few signs of war, aside from the many soldiers, and even the
+bombardment of a few hours earlier appeared to have been forgotten. But
+of course there was grief in many hearts.
+
+It was early the next morning, when Tom and Jack were getting ready to
+go back to the ruins in the Rue Lafayette, that, as they left their
+lodgings, they heard in the air above them the familiar sounds of
+aeroplanes in flight, and the faint popping of machine guns, to which
+was added the burst of shrapnel.
+
+"Look!" cried Jack. "It's a battle in the air. The Huns are making
+another raid. Now we'll see how they bomb the city."
+
+But it did not turn out to be that sort of raid. The German craft were
+flying low, apparently to get a view of the havoc wrought the day
+before. Possibly photographs were being taken.
+
+But the French aeroplanes were ready for the foe, and at once arose to
+give battle, while the anti-aircraft guns roared out a stern order to
+retreat. It was a battle above the city and, more than once, Tom and
+Jack wished they could be in it.
+
+"We'll have to get back to our hangars soon," mused Tom, as they watched
+the fight. "We can't be slackers, even if I can't find my father," he
+added bravely.
+
+The French planes were too much for the Germans, and soon drove them
+back beyond the Hun lines, though perhaps not before the enemy aviators
+had made the observations desired.
+
+"Well, they didn't see much," remarked Jack. "As far as any real damage
+was done to Paris it doesn't count, from a military standpoint."
+
+"No, you're right," agreed Tom. "Of course they have killed some
+noncombatants, but that seems to be the Boche's principal form of
+amusement. As for getting any nearer to the capture of Paris this way,
+he might as well throw beans at the pyramids. It's probably done for the
+moral, or immoral, effect."
+
+And this seemed to be the view taken of it by the Paris and London
+papers. The method of bombardment, however, remained a mystery, and a
+baffling one. This was a point the military authorities wished to clear
+up. To that end it was much to be desired that fragments of the shell
+should be found. And to find them, if possible, a careful search was
+made, not only in the ruins of the Rue Lafayette, but at the other two
+places where the explosions had occurred.
+
+In no place, however, was a large enough fragment found to justify any
+conclusive theories, and the Parisians were forced to wait for another
+bombardment--rather a grim and tense waiting it was, too.
+
+But the careful search of the Rue Lafayette ruins proved one thing. The
+body of Tom's father was not among them, though this did not make it
+certain that he was alive. He may have been totally destroyed, and this
+thought kept Tom from being able to free his mind of anxiety. He dared
+not cable any news home, and all he could do was to keep on hoping.
+These were anxious days for him and Jack.
+
+Their leave of absence had been for a week only, but under the
+circumstances, and as it was exceptionally quiet on their sector, they
+were allowed to remain longer. Tom wanted to make a more thorough search
+for his father, and the police and military authorities helped him. But
+Mr. Raymond seemed to have completely disappeared. There was no trace of
+him since the agent for the Rue Lafayette buildings had seen him leave
+his room just prior to the falling of the shell.
+
+Jack inquired about the man he suspected of being a German spy. The
+secret service men had him under observation, they reported, but, as
+yet, he had not given them any cause to arrest him. They were waiting
+and watching.
+
+Meanwhile active preparations were under way, not only to discover the
+source of the bombardment of Paris, but to counteract it. Extra
+anti-aircraft guns, of powerful calibre, were erected in many places
+about the city, and more airmen were summoned to the defense.
+
+As yet there had been no resumption of the bombardment, and there were
+hopes that the German machine, whatever it was, had burst or been put
+out of commission. But on the second day of the second week of the boys'
+stay in Paris, once more there was the alarm and the warning-from the
+soldiers and police, and again came that explosion.
+
+The bombardment of Paris was being renewed!
+
+
+
+
+CHAPTER IX
+
+VARIOUS THEORIES
+
+
+Two things were at once apparent to Tom and Jack as they hurried out of
+their _pension_. One was that the people of Paris were not seeking
+shelter after the warnings as quickly as they had done at first, and the
+other was that there was evident curiosity on all sides to see just what
+damage would be done, and from which direction it would come. With an
+almost reckless disregard for their safety, if not for their lives, the
+Parisians fairly flocked out of doors to see the results of the Huns'
+bombardment. It was in vain that the police and military urged them to
+seek safety in cellars or the places provided.
+
+This time only one shell fell near enough to Tom and Jack to make the
+explosion heard, and that was so faint as to indicate that it was some
+distance off. What damage had been done could only be guessed at.
+
+"But we'll find out where it is, and go take a look," said Jack.
+
+"Maybe it'll hit right around here if we stay," suggested his chum.
+
+"Well, I'm not taking that chance," Jack went on. "Let's find out where
+it landed this time."
+
+This they could do through their acquaintance with the military
+authority of the district where they were then staying. A telephonic
+report was at once received, giving the quarter where the shell had
+landed. It had fallen in one of the public squares, and though a big
+hole had been torn in the ground and pavement, and several persons
+killed and wounded, no material damage had been done. As for any
+military effect of the shell, it was nil.
+
+The firing was done in the early evening hours, and Tom and Jack learned
+that, almost to the second, the shots were fifteen minutes apart.
+
+There was one theory that an underground passage had been made in some
+manner to within a comparatively few miles of Paris, and from that point
+an immense mortar sent up the shells in a long trajectory.
+
+Another theory was that traitors had let the Germans through the French
+lines at a certain place, so they could get near enough to Paris to
+bombard it.
+
+And of course the gigantic airship theory had its adherents.
+
+But, for a time at least, no one would admit the possibility of a gun
+with range sufficient to shoot into Paris from the nearest German lines.
+The range, sixty-odd miles, seemed too great for practical belief,
+however nicely it might work out in theory.
+
+"And you must remember that the gun, if gun it is, couldn't be in the
+very first German line," said Tom, who had studied ordnance. "It must be
+at least ten miles back, to allow for sufficient protection from the
+French guns. That would make it shoot about seventy-two miles, and I
+don't believe any gun on earth could do it!"
+
+"Neither do I," added Jack. "We've got to dope out something else. But
+this isn't finding your father, Tom."
+
+"I know it, and I don't mind admitting I'm clean discouraged about him,
+Jack. If he's alive why doesn't he send me some word? He must know where
+I am, and, even if he doesn't know I'm in Paris, they would forward any
+message he might send to our aeroplane headquarters."
+
+"That's right. But what are you going to do about it?"
+
+"I hardly know. He may still be in Paris, but it's such a big city that
+it's hard to find him. Then, too, I'm thinking of something else."
+
+"What's that, Tom?"
+
+"Well, dad may not want us to know where he is."
+
+"Why in the world would he want such a thing as that?"
+
+"Well, he might be followed, or bothered by spies. Perhaps he has come
+over to do some special work for the French or English army people.
+Maybe a spy was after him just before the big German gun wrecked his Rue
+Lafayette house. He may have considered this a good chance to play dead,
+and that's why he doesn't send some word to me."
+
+"That's a good theory. But it isn't very comforting."
+
+"No, but there isn't much comfort in war times. We've got to make the
+best of it."
+
+"I guess you're right, Tom. Now do you want to go look at the latest
+work of the Hun?"
+
+"Might as well. The bombardment seems over for the night."
+
+"I wonder why it is they don't fire after dark."
+
+"Probably afraid of giving the location of their cannon away by the
+flashes. They'd be seen at night; but during the day, if they used
+smokeless powder, or a smoke screen in case they can't get smokeless
+powder for such a big gun, it would be hard to locate the place where
+the shots come from. So we're comparatively safe after dark, it seems."
+
+Later this was not to prove to be the case, but it was when Tom spoke.
+
+The boys went to the section of the city in which the last shells had
+fallen. While comparatively little damage had been done, a number of
+persons had been killed and injured, children among them. Some fragments
+of the shells were picked up, but not enough to make certain any
+particular theory in regard to the gun.
+
+"But if it's a gun, where could it be placed?" queried Tom of an
+officer. "The Germans haven't broken through, have they?"
+
+The French officer shook his head.
+
+"No. And please God they will never get through," he said. "But there is
+a gun somewhere, I am sure of that."
+
+"Do you mean to say within ten or fifteen miles of Paris?" Jack wanted
+to know.
+
+"I can not be sure. It is true there may have been traitors. We have
+them to contend with as well as spies. But our line is intact, and at no
+point along it, near enough to it to fire into Paris from an ordinary
+gun, can the Germans be found."
+
+"Then it must be an extraordinary gun," suggested Jack.
+
+"It may well be--perhaps it is. Yet, as I said, there may have been
+traitors. There may be a gun concealed somewhere closer to Paris than we
+dream. But we shall find it, messieurs! Who knows? Perhaps you may be
+the very ones yourselves to locate it, for we are depending on you
+soldiers of the air."
+
+And it was not long before this talk came back to Tom and Jack with
+impressive recollection.
+
+And meanwhile the bombardment of Paris went on, usually during the late
+afternoon or early morning hours--never at night, as yet.
+
+Yet with all the frightfulness of which the unscrupulous Huns were
+capable, it was impossible to dampen for long the spirits of the French.
+Soon they grew almost to disregard the falling shells from the hidden
+German gun. Of course there were buildings destroyed, and lives were
+lost, while many were frightfully maimed. But if Germany depended on
+this, as she seemed to, to strike terror to the hearts of the brave
+Frenchmen the while a great offensive was going on along the western
+front, it failed. For the people of Paris did not allow themselves to be
+disheartened, any more than the people of London did when the Zeppelins
+raided them.
+
+Indeed one Paris paper even managed to extract some humor out of the
+grim situation. For one day, following the bombardment, a journal
+appeared with "scare" headlines, telling about eleven "lives" being
+lost. But when one read the account it was discovered that the lives
+were those of chickens.
+
+And this actually happened. A shell fell on the outlying section and
+blew up a henhouse, killing nearly a dozen fowls and blowing a big hole
+in the ground.
+
+There were other occasions, too, when the seemingly superhuman
+bombardment was not worth the proverbial candle. For the shells fell in
+sections where no damage was done, and where no lives paid the toll.
+Once a shell went through a house, passing close to an aged woman, but
+not hurting her, to explode harmlessly in a field near by.
+
+And it was with such accounts as these that the Paris papers kept up the
+spirits of the inhabitants. Meanwhile the Germans kept firing away at
+quarter-hour intervals, when the gun was in action.
+
+"I wonder if there is any chance of us getting in at the game?"
+questioned Jack of Tom one night.
+
+"I shouldn't be surprised. As that officer said, they'll have to depend
+on the aircraft to locate the gun, I'm thinking."
+
+"And you think we have a chance?"
+
+"I don't see why not," replied Tom. "We've been off duty long enough.
+I'd like to get back behind the propeller again, and with a drum or two
+of bullets to use in case we sight a Hun plane. Let's go and send word
+to our captain that we've had enough of leave, and want to go out
+again."
+
+"All right. But what about your father?"
+
+"Well, I don't know what to say," answered Tom. "I'm about convinced
+that he wasn't killed, or even hurt, in any of the bombardments of
+Paris. But where he is I don't know. I guess, as a matter of duty to
+France, I'll have to let my private affairs go and--"
+
+At that instant there sounded an explosion the character of which the
+two boys well knew by this time.
+
+"The big gun again!" cried Jack.
+
+"Yes, and they're firing after dark!" added Tom. "This may be just the
+chance the airmen have been waiting for--to locate the piece by the
+flashes. Come on out and see what's doing!"
+
+Together they rushed from their room.
+
+
+
+
+CHAPTER X
+
+THE "DUD"
+
+
+Much the same sort of scene was going on in the streets of Paris as Tom
+and Jack had witnessed when first the populace realized that they were
+under fire from a mysterious German cannon. There was the initial
+alarm--the warnings sounded by the police and soldiers, warnings which
+were different from those indicating a Zeppelin or aircraft raid, and
+then the hurry for cover.
+
+But it was noticeable that not so many of the people rushed for a secure
+hiding place as had done so at first.
+
+"They're not so afraid of the big gun as they were," observed Jack, as
+he hurried along with his chum.
+
+"No. Though it's just as well to be a bit cautious, I think. The people
+of Paris are beginning to lose fear because they see that the German
+shells don't do as much damage as might be expected."
+
+"You're right there, Tom," said Jack. "The shells are rather small, to
+judge by the damage they do. I wonder why that is?"
+
+"Probably their gun, or guns, can't fire any larger ones such a long
+distance, or else their airships can't carry 'em up above the clouds to
+drop on the city."
+
+"Then you still hold to the airship theory?"
+
+"Well, Jack, I haven't altogether given it up. I'm open to conviction,
+as it were. Of course I know, in theory, a gun can be made that will
+shoot a hundred miles, if necessary, but the cost of it, the cost of the
+charge and the work of loading it, as well as the enormous task of
+making a carriage or an emplacement to withstand the terrific recoil,
+makes such a gun a military white elephant. In other words it isn't
+worth the trouble it would take--the amount of damage inflicted on the
+enemy wouldn't make it worth while."
+
+"I guess you're right, Tom. And yet such a gun would make a big scare."
+
+"Yes, and that's what the Germans are depending on, more than anything
+else."
+
+"But still don't you think the French will have to do something toward
+silencing the gun?"
+
+"Indeed I do! And I haven't a doubt but the French command is working
+night and day to devise some plan whereby the gun can be silenced."
+
+"There go the aviators now, out to try to find the big cannon,"
+observed Jack, as he gazed aloft.
+
+Soaring over Paris, having hastened to take the air when the signal was
+given, were a number of planes, their red, white and blue lights showing
+dimly against the black sky. They were off to try to place the big gun,
+if such it was, or discover whether or not some Hun plane was hovering
+over the city, dropping the bombs.
+
+As Jack and Tom hastened on, in the wake of the crowd, which was
+hurrying toward the place where the latest shells had fallen, again came
+a distant explosion, showing that the gun had been fired again.
+
+"Fifteen-minute interval," announced Tom, looking at his watch. "They're
+keeping strictly to schedule."
+
+"Night firing is new for the big gun," said Jack. "I do hope they'll be
+able to locate the cannon by the flashes."
+
+"It isn't going to be easy," asserted Tom.
+
+"Why not?"
+
+"Because you can make up your mind if the Germans were afraid to fire
+the piece at night at first for fear of being discovered, and if now
+they are firing after dark, they have some means of camouflaging the
+flash. In other words they have it hidden in some way."
+
+"Well, I suppose you're right. But say, Tom, old man! what wouldn't I
+give to be able to be up in the air with those boys now?" and Jack
+motioned to the scouts who were flitting around in the dark clouds,
+seeking for that which menaced the chief city of the French nation.
+
+"I'd like to be there myself," said Tom. "And if this keeps up much
+longer I'm going to ask permission for us to go up and see what we can
+do."
+
+"Think they'll let us?"
+
+"Well, they can't any more than turn us down. And we've got to get at it
+in a hurry, too, or we'll have to report back at our regular station. We
+aren't doing anything here, except sit around."
+
+"No, we must get busy, that's a fact," said Jack. "It's about time we
+downed some Hun scout, or broke up one of their 'circus' attacks. I've
+almost forgotten how a joy stick feels."
+
+A "joy stick" is a contrivance on an aeroplane by the manipulation of
+which the plane is held on a level keel. If the joy stick control is
+released, either by accident (say when the pilot is wounded in a fight),
+or purposely, the plane at once begins to climb, caking its passenger
+out of danger.
+
+Once the joy stick is released it gradually comes back toward the
+pilot. The machine climbs until the angle formed is too great for it to
+continue, or for the motor to pull it. Then it may stop for an instant
+when the motor, being heavier, pulls the plane over and there begins the
+terrible "nose spinning dive," from which there is no escape unless the
+pilot gets control of his machine again, or manages to reach the joy
+stick.
+
+"Well, we'll have to get in the game again soon," said Tom. "But what do
+you say to taking a taxi? This explosion is farther than I thought."
+
+Jack agreed, and they were soon at the place where the last German shell
+had fallen--that is as near as the police would permit.
+
+A house had been struck, and several persons, two of them children,
+killed. But, as before, the military damage done was nothing. The
+Germans might be spreading their gospel of fear, but they were not
+advancing their army that way.
+
+As Tom and Jack stood near the place where a hole had been blown through
+the house, another explosion, farther off, was heard, and there was a
+momentary flare in the sky that told of the arrival of another shell.
+
+For a few seconds there was something like a panic, and then a voice
+struck up the "Marseillaise," and the crowd joined in. It was their
+defiance to the savage Hun.
+
+A few shots were fired by the Germans, but none of them did much damage,
+and then, as though operating on a schedule which must not, under any
+circumstances, be changed, the firing ceased, and the crowds once more
+filled the streets, for it was yet early in the night.
+
+The next morning the boys went to report, as they did each day,
+expecting that they might be called back to duty. They also found, after
+being told that their leave was still in effect, that some of the
+aviators who had gone up the night before, to try to locate the German
+gun, were on hand.
+
+"Now we can ask them what they saw," suggested Jack.
+
+"That's what we will," assented Tom.
+
+But the airmen had nothing to report. They had ascended high in search
+of a hostile craft carrying a big gun, but had seen none.
+
+They had journeyed far over the German lines, hoping to discover the
+emplacement of the gun, if a long range cannon was being used. But they
+saw nothing.
+
+"Not even flashes of fire?" asked Tom.
+
+"Oh, yes, we saw those," an aviator said. "But there were so many of
+them, and in so many and such widely scattered places, that we could
+not tell which one to bomb. We did manage to hit some, though with what
+effect we could not tell."
+
+"Then the German gun is still a mystery," observed Tom.
+
+"It is. But we shall discover it soon. We will never rest until we do!"
+
+So more and new and different theories continued to be put forth
+regarding the big cannon, if such it was. Ordnance experts wrote
+articles, alike in London, Paris, and New York, explaining that it was
+possible for a cannon to be within the German lines and still send a
+shell into the French capital. But few believed that it was feasible.
+The general opinion was that the gun was of comparative short range, and
+was hidden much nearer Paris than the sixty or seventy-odd miles away,
+beyond which stretched the German line of trenches.
+
+Meanwhile Tom, though making careful inquiries, had learned nothing of
+his father. He did not feel it would be wise to cable back home, and ask
+what the news was there.
+
+"It might spoil dad's plans if I did that," said Tom to his chum, "and
+it would worry the folks in Bridgeton to know that I haven't yet seen
+him in France. No, I'll just have to wait."
+
+And wait Tom did, though there is no harder task in all the world.
+
+It was one morning, after a night bombardment on the part of the
+Germans, that Jack, who had been out for a morning paper, came rushing
+into the room where Tom was just awakening.
+
+"Great news, old man! Great!" cried Jack, waving the paper about his
+head.
+
+"You mean about a victory?" asked Tom.
+
+"No, not exactly, though it may lead to that. And it isn't any news
+about your father, I'm sorry to say. It's about the German gun. A 'dud'
+fell last night."
+
+"A 'dud'?" repeated Tom, hardly sensing what Jack said.
+
+"Yes, you know! A shell that didn't explode. Now they have a whole one
+to examine, and they can find out what sort of gun shot it. This paper
+tells all about it. Come on! Let's go for a look at the 'dud'!"
+
+
+
+
+CHAPTER XI
+
+A MONSTER CANNON
+
+
+Tom, dressing hastily, read the account in the Paris paper of the fall,
+in an outlying section of the city, of one of the German shells that
+failed to explode. It was being examined by the military authorities, it
+was stated, with a view to finding out what sort of gun fired it, so
+that measures might be taken to blow up the piece or render it useless
+to the enemy.
+
+"That sounds good to me," said Tom, as they made a hasty breakfast.
+"This is getting down to a scientific basis. An unexploded shell ought
+to give 'em a line on the kind of gun that fired it."
+
+"The only trouble," said Jack, "is that the shell may go off when they
+are examining it."
+
+"Oh, trust the French ordnance experts not to let a thing like that
+happen," said Tom. "Now let's go to it."
+
+It was fortunate that Tom and Jack wore the uniforms that had so
+endeared them to France, or they might have had difficulty in gaining
+admittance to the bureau where the unexploded shell was under process
+of investigation. But when they first applied, their request was
+referred to a grizzled veteran who smiled kindly at them, patted them on
+the shoulders, called them the saviors of France, and ushered them into
+the ordnance department, where special deputies were in conference.
+
+"Yes, we have one of the Boche shells," said an officer, who spoke
+English fluently, for which Tom and Jack were glad. They could speak and
+understand French, but in a case like this, where they wanted a detailed
+and scientific explanation, their own tongue would better serve them.
+
+"And can you tell from what sort of gun it comes?" asked Tom.
+
+"It was fired from a monster cannon," was the answer. "That is a cannon
+not so much a monster in bore, as in length and in its power to impel a
+missile nearly eighty miles."
+
+"Can it be done?" asked Jack.
+
+"It has been done!" exclaimed Major de Trouville, the officer who was
+detailed to talk to the boys "It has been done. That is the gun that has
+been bombarding Paris."
+
+"But, from a military standpoint," began Tom, "is it--"
+
+"It is utterly useless," was the quick answer. "Come, I will show you
+the shell."
+
+He led them to an apartment set aside for the testing of explosives and
+working out ordnance problems, and there on a table, around which sat
+many prominent French officials, was the German shell--the "dud," as
+Jack had called it.
+
+"The charge has been drawn," explained Major de Trouville, "so there is
+no danger. And we have determined that the manner in which shots reach
+Paris from a distance of from seventy to eighty miles is by the use of a
+sub-calibre missile."
+
+"A sub-calibre?" murmured Tom.
+
+"Yes. You know, in general, that the more powder you use, and the larger
+the surface of the missile which receives it, the greater distance it
+can be thrown, providing your angle of elevation is proper."
+
+The boys understood this much, in theory at least.
+
+"Well," went on the major, "while that is true, there is a limit to it.
+That is to say you could go on using powder up to hundreds of pounds in
+your cannon, but when you get to a certain point you have to so increase
+the length of the gun, and the size of the breech to make it withstand
+the terrific pressure of gases, that it is impracticable to go any
+further. So, also, in the case of the shell. If you make it too large,
+so as to get a big surface area for the gases of the burning powder to
+act upon, you get your shell too heavy to handle.
+
+"Now of course the lighter a missile is, the farther it will go, in
+comparison to a heavy one with the same force behind it. But you can not
+get lightness and sufficient resistance to pressure without size, and
+here is where the sub-calibre comes in."
+
+"In other words the Germans have been firing a shell within a shell,"
+broke in another officer.
+
+"Exactly," said Major de Trouville. "The Germans have evolved a big gun,
+that is big as regards length, to enable the missile they fire from it
+to gain enough impulse from the powder. But the missile would be too
+large to travel all the way to Paris. So they use two. The inner one is
+the one that really gets here and explodes."
+
+"What becomes of the outer?" asked Jack.
+
+"It is a sort of container, or collar, and falls off soon after the
+shell leaves the big gun. If you will imagine a sort of bomb shell being
+enclosed in an iron case, the whole being put in a gun and fired, you
+will better get the idea. The outer case is made in two or more pieces,
+and soon after it is shot out it falls away, leaving the smaller missile
+to travel on. But here is where the cunning of the invention comes in.
+The smaller missile has all the impetus given the larger one, but
+without its weight. In consequence it can travel through eighty miles of
+atmosphere, finally reaching Paris, where it explodes."
+
+"Wonderful!" exclaimed Jack.
+
+"And yet it is merely the adaptation of an old theory," went on the
+major. "We have known of the sub-calibre theory for years, but it is not
+practicable. So we did not try it. The cost is too great for the amount
+of military damage done. And this shell, as you will see, is composed of
+two parts, each with a separate explosive chamber, each containing, as
+we discovered, a different sort of explosive. In this way if one did not
+go off, the other would, and so set off the one that failed. It is very
+clever, but we shall be more clever."
+
+"That's right!" chimed in a chorus of fellow officers.
+
+"We'll find the gun and destroy it--or all of them if they have more
+than one, as they probably have," went on the major.
+
+He showed the boys where the shell had chambers for the time fuses to
+work, much as in a shrapnel shell, which can be set to go off so many
+minutes or so many seconds after it reaches its objective point.
+
+"And so the great question is settled by the failure of this shell to
+explode," went on the major. "As soon as we saw it, and noted the
+absence of the rifling groove marks, we knew it must have been a
+sub-calibre matter. The rest was easy to figure out.
+
+"Some of us thought there might be a big airship, stationed high above
+the clouds, dropping bombs. Others inclined to the theory of a double
+shell; that is, after one had been fired from the cannon it would
+travel, say, half way and then explode a charge which would impel
+another shell toward Paris. A sort of cannon within a cannon, so to
+speak. But this is not so. Nor did the theory of a shell with a sort of
+propeller device, like that of a torpedo, prove to be right. It is much
+simpler--just sub-calibre work."
+
+"And what is going to be done about it?" asked Tom. "I mean how can the
+monster cannon be silenced?"
+
+"Ah, that is a matter we are taking up now," was the answer of Major de
+Trouville. "I fancy we shall have to call on you boys for a solution of
+that problem."
+
+"On us?" exclaimed Jack.
+
+"Well, I mean on the aircraft service. It will be their task to search
+out this great German cannon for us, to enable our gunners to destroy
+it. Or it may be that it will have to be bombed from an aeroplane."
+
+"That's the task I'd like all right!" cried Tom, with shining eyes.
+
+"Same here!" echoed Jack. "Do you suppose we'll get a chance?" he asked
+eagerly.
+
+"You may," was the reply. "It may take all the resources of our airmen
+to destroy this terror of the Germans. But it will be done, never fear!"
+
+"_Vive la France!_" cried his companions, and there was a cheer in which
+Tom and Jack joined.
+
+And so a part of the secret was discovered. It was a monster cannon that
+was devastating Paris. A great gun, the construction of which could only
+be guessed at. But it must be destroyed! That was certain!
+
+
+
+
+CHAPTER XII
+
+FOR PERILOUS SERVICE
+
+
+Tom and Jack spent some little time looking at the strange German shell.
+It was of peculiar construction, arranged so that the two explosive
+charges would detonate together or separately, according as the
+mechanism was set.
+
+But in this case it had failed to work, and the shell, falling in a bed
+of soft sand, near some new buildings which were going up, had not been
+fired by concussion, as might have happened.
+
+"And it was just French luck that it didn't go off," observed Jack.
+
+"That's right," agreed Tom. "If they hadn't had this whole shell to
+examine they wouldn't know about the big gun."
+
+So all the theories, fantastic enough some of them, about great airships
+hovering over the beautiful city, and dropping bombs from a great
+height, were practically disproved.
+
+"Well, now that you have decided it is a big German gun, the next
+question is, where is it and what are you going to do about it?"
+observed Tom, for he and Jack had been made so much of by the French
+officers that they felt quite at home, so to speak.
+
+"Ah, messieurs, that _is_ the question," declared Major de Trouville.
+"First to find the gun, and then to destroy it. The first we can do with
+some degree of accuracy."
+
+"How?" asked Tom.
+
+The major went to a large map hanging on the wall of the room. It showed
+the country around Paris and the various lines as they had been moved to
+and fro along the Western front, according as the Germans advanced or
+retreated.
+
+"You will observe," said the major, "that by describing an arc, with
+Paris as the center of the circle, and a radius of about seventy-five
+miles, you will include a small sector of the German trenches. Roughly
+speaking this arc will extend from about Hamegicourt to Condé, both
+within the German lines, I am sorry to say. Now then, somewhere in this
+arc, or perhaps back of it, the German gun is placed. Anywhere else
+where it would be possible for such a monster engine of war to be
+erected, would bring it too close to our batteries.
+
+"So that gives us the comparative location of the gun," went on the
+French officer. "But the next question is not so easy to settle--how to
+get rid of it. As I said, I think we shall have to depend on you
+airmen."
+
+"Well, we're for the job!" exclaimed Tom.
+
+"I know you are. And it may fall to you, or to your friends. I will talk
+of that later."
+
+"Have you been able to get any idea of the kind of gun it is, or why it
+fires at fifteen minute intervals?" asked Jack.
+
+"We have been able to get no really reliable information save that which
+we deduce by our observations of this shell and from what we know of the
+location of our own and the German lines," the Major went on. "Up to now
+our airmen have not been able to penetrate far enough without being
+attacked, and such few as did get well over toward the Rhine could make
+out nothing. I have no doubt the gun is well camouflaged."
+
+"And is it true that it doesn't fire at night because the Germans are
+afraid the flashes will be seen?" asked Tom.
+
+"That may have been the reason at first, but they have fired at night,
+of late, so they must have some way of concealing the flashes, or
+perhaps setting off other flashes at the same time so as to confuse our
+scouts."
+
+"It's going to be some job," murmured Jack.
+
+"You said something," agreed his chum.
+
+They remained talking a little longer, and some of the officers who
+knew the reason for Tom's visit to Paris, expressed regret that he had
+no information as yet about his father.
+
+"But take heart," one told him. "He is not dead, or we should have heard
+of it. Of course he may have fallen into the hands of the Germans, and
+then we would not know for some time."
+
+"He may have been caught," agreed Tom. "While Tuessig is out of the game
+on account of his injuries, he may be able to direct Potzfeldt, and that
+scoundrel would have good reason for trying to get revenge on us."
+
+"Ah, yes, I heard about your rescue of the young lady and her mother,"
+said the major. "It was a brave deed."
+
+"Oh, any one could have done it," said Tom, modestly.
+
+"And have you seen them since they came to Paris?" the major proceeded.
+
+"No, but I wish we could find them!" burst out Jack, and then he blushed
+at his impetuosity, while Tom murmured something about "Bessie," and
+Jack promptly told him to hold his tongue.
+
+"Perhaps you may meet them sooner than you expect," went on the French
+officer.
+
+"Now I wonder what he could have meant by that?" asked Jack, as he and
+his chum went out, after a final look at the German shell. "Does he
+know where they are?"
+
+"It wouldn't be surprising, seeing that Mrs. Gleason is probably in Red
+Cross work, and Bessie may be helping her. We should have looked them up
+before," went on Tom. "But what with searching for my father, and the
+excitement about the bombardment, I really forgot all about them."
+
+Jack did not say whether he had or not, the chances being that he had,
+more than once, thought of Bessie Gleason.
+
+During the next two days the monster cannon continued to shoot shells at
+intervals into Paris. Some did considerable damage, as any shell would
+do in a great city, and many unfortunates were killed. But there was no
+reign of terror such as, undoubtedly, the Boches hoped to create. Paris
+remained calm, and there were even jokes made about the cannon. It was
+called a "Bertha" and other names, the former referring to Bertha Krupp,
+one of the owners of the great German ordnance works.
+
+Word was given out that the French gunners on the front were trying to
+reach the big gun with their missiles. But as they were firing blindly
+it could not be said what havoc had been wrought.
+
+"But, sooner or later, we'll get the range, and get within striking
+distance," said one of the French officers. "Then we'll show them a
+trick or two."
+
+"Have the aviators done anything toward trying to find the gun?" asked
+Tom. "I mean anything more."
+
+"We are perfecting our plans for the flying corps," was the answer.
+"Perhaps you shall know more in a few days."
+
+"Well, I hope we'll be here when the fun begins," said Tom, grimly.
+"We've got another extension of leave, and I'm going to ask the police
+now, to co-operate with the military in seeking my father."
+
+"I think that will be a wise plan. We will give you all the help we
+can."
+
+But the quest for Mr. Raymond seemed a hopeless one, and as no
+confirmation could be had of his death or injury, the idea gradually
+became fixed in the minds of Tom and Jack that he had been made a German
+prisoner.
+
+"If that is so, and I can get any trace of him, I'll go over the Rhine
+to get him back," snapped Tom.
+
+"And I'll go with you!" declared his chum.
+
+It was a few days after they had inspected the German "dud," and the
+boys were wondering what new developments might take place, the shelling
+of Paris meanwhile continuing at intervals, that one evening the boys
+were visited in their lodgings by Major de Trouville.
+
+"Is there any news?" eagerly asked Tom, for he guessed that the French
+officer would not be paying a merely social call. Those were the
+strenuous days when such things had passed.
+
+"Well, yes, news of a sort," was the answer. "But what I came to find
+out was whether you were so taken with these lodgings that you could not
+be induced to move."
+
+"To move!" exclaimed Jack.
+
+"Yes. Have you found anything unhealthful here?"
+
+"Why, no," replied Tom, wonderingly. "We like it here. The landlord
+couldn't be nicer, and we're in a good location."
+
+"Nevertheless, I fear I shall have to ask you to change your quarters,"
+went on the major, and by the quizzical smile on his face the boys
+guessed that there was something in the wind.
+
+"Let me ask you another question," went on the French officer. "Have you
+been annoyed since you have been here?"
+
+"Annoyed? How?" inquired Tom.
+
+"By unwelcome visitors, or by strangers."
+
+The boys thought for a moment.
+
+"There's one chap who lives in the same building here, whom we've seen
+on our staircase several times," said Jack, slowly. "Once I saw him
+pause at our door with a key, as though he were going to enter, but he
+heard me coming, and, muttering that he had taken too much wine and was
+a bit hazy in his memory, he went on upstairs."
+
+"I thought as much," the major said. "Was the man you speak of familiar
+to you?"
+
+"No, I can't say that he was," replied Jack, and Tom nodded his
+acquiescence. "I never saw him before."
+
+"Oh, yes you have," and the major smiled.
+
+"I have? Where?"
+
+"On the train, coming into Paris."
+
+"You mean the German spy?" cried Jack.
+
+"The same," answered the Frenchman. "That's just what he is, and he is
+spying on you. Now, in view of what is going to happen, we don't want
+that to go on. So I have come to ask you to change your lodgings, and I
+think I can take you to one that will be most agreeable to you both."
+
+"But what does all this mean?" asked Tom. "Is there----"
+
+"There is 'something doing' as you say so picturesquely in the United
+States," interrupted the major. "I have come to tell you that you are to
+undertake a most perilous mission!"
+
+
+
+
+CHAPTER XIII
+
+THE SPY
+
+
+Tom Raymond and Jack Parmly looked first at one another and then at the
+major. He had been smiling at their wonderment, but he was now serious,
+and regarded them gravely.
+
+"Do you mean we have to do something to help catch this spy?" asked Tom.
+
+"I'd like a hand in that!" exclaimed Jack. "I saw him first--he's my
+meat!"
+
+"Well, get him if you can, boys," said the Frenchman. "But I did not
+come here to talk so much about him as about yourselves. The spy is a
+danger and a menace, but we know him and if he goes too far we can put
+out our hands and drag him back.
+
+"No, what I referred to is more dangerous than merely trying to catch a
+spy at his sneaking work. I will tell you." The major suddenly left his
+seat near the window of the boy's room, and quickly opened the door
+leading to the hall. The passage was empty.
+
+"I rather thought there might be an eavesdropper," the major explained.
+"I was followed here, though I don't believe the spies know my mission.
+However, it is best to be careful. With your permission I'll pull down
+the shade. There may be spies stationed across the street who, with
+powerful glasses, might look through the window and gather something of
+what we say by reading our lips. It has been done."
+
+"The Germans don't leave much untried," commented Tom. "But what is it
+you want us to do, if it isn't trying to trail the spy?"
+
+The major motioned them to draw closer to him, and then, leaving the
+door into the hall open, so that he could note the approach of any one,
+he whispered:
+
+"You are to be two members of a picked company of air scouts who are to
+go out, discover the big German gun, and destroy it!"
+
+"Whew!" whistled Tom, after a moment of thought during which he and Jack
+exchanged quick glances.
+
+"Well?" asked the officer. "How does that strike you? I believe that is
+another of your captivating terms?"
+
+"It's all to the good!" exclaimed Jack. "What say, Tom? We'll take that
+on, won't we?"
+
+"Well, I should say!" was the enthusiastic rejoinder. "When do we start
+to--"
+
+"Hush!" cautioned the major. "Not so loud. Though we have taken every
+precaution, there may be spies unseen by us. We had better talk no more
+about it here."
+
+"Then let's go to our new lodgings, if we are to move," suggested Tom.
+"Will it be safe to talk there?"
+
+"I think so," the major said. "At least you will be among friends. Not
+that your landlord here is not a true Frenchman; but he can not control
+the actions of those to whom he lets lodgings. You will be better where
+you are going. Then you accept the mission?" he asked in another
+whisper.
+
+"Sure thing!" answered Tom, while Jack nodded his assent. "The sooner
+the quicker!"
+
+"I do not quite get that," the major confessed with a smile. "But I
+think I gather your meaning. Now if you will proceed to this address,"
+and he handed Tom a small slip of paper, "you will find a comfortable
+lodging, and you will be among friends."
+
+"How soon can we start on--on this mission?" asked Tom.
+
+"It will be better not to refer to it directly," the officer said. "Talk
+as little about it as you can. But you shall go as soon as the
+arrangements can be made. You will be notified."
+
+"And what about seeing our friends--Mrs. Gleason?" asked Jack.
+
+"Are you sure its _Mrs._. Gleason you want to see?" inquired Tom.
+
+"Oh, cut it out!" advised Jack with a blush.
+
+"You may see them soon now," the major told him with a smile. "And I
+hope you'll soon have good news of your father," he added to Tom.
+
+"I hope so, too. The suspense is telling on me."
+
+"I should think it would. Now don't leave this bit of paper about with
+the address of your new lodgings on. Better commit it to memory, and
+then destroy the sheet. We want, if possible, to prevent the spy from
+knowing where you have gone. I will call a taxicab for you. You can be
+packed soon, I suppose?" he questioned.
+
+"Within a half hour," answered Jack. "But say, won't that spy be on the
+watch, and won't he learn from the taxicab driver where we have gone?"
+
+"Not from _this_ taxicab driver," was the smiling answer. "He is one of
+our best secret service men. But treat him as you would an ordinary
+chauffeur. You may even give him a tip, and he will not be offended,"
+and once more the major smiled.
+
+Tom and Jack, having made sure they remembered the address given them,
+destroyed the paper, and then proceeded to get ready to move. Meanwhile
+Major de Trouville took his departure, promising to keep in
+communication with the Air Service boys.
+
+Punctual to the half hour a taxicab appeared at the door. The boys
+obeyed the instructions they had received, and looked out to make sure
+the spy was not on hand. If he was, he was well concealed, for they did
+not see him.
+
+"Though I suppose he's somewhere around," said Jack.
+
+"Well, maybe we can fool him," suggested Tom. "We're going quite on the
+other side of Paris."
+
+They made sure that, as far as could be told by observation, there was
+no one resembling the spy around the place or in the street in front,
+and then got into the cab with their baggage. The chauffeur seemed not
+to know them, but Tom thought there was just the slightest wink of one
+eye, as though to indicate that the game was going well.
+
+Their cab was driven out along the Boulevard Ragenta, past the Gare du
+Nord, and across the Boulevard de Rochechquart to a small street running
+off the Rue Ramey, and there the cab stopped in front of a small but
+neat-looking house.
+
+"Quiet enough neighborhood," remarked Jack, as they got down, and Tom
+tipped the cabman for the benefit of any spies who might be looking.
+
+"Yes, I guess we can get some sleep here, if the big gun doesn't keep us
+awake," agreed Tom.
+
+On the way they had passed several places where the havoc of the
+"Bertha" was noticeable.
+
+Tom and Jack seemed to be expected, for the porter, who came down to get
+their bags, did not seem at all surprised to see them. He bade them
+follow him, and a little later, the cab having chugged off, the boys
+were settled in a pleasant room, a smiling landlady coming in to see if
+they wanted anything, and to tell them they could have meals with her at
+certain hours, or they might dine out as they pleased.
+
+"Your friends will be here shortly," she added.
+
+"Our friends?" questioned Tom.
+
+"Yes," with a nod and a smile. "I was told to say they would be here
+shortly after you arrived."
+
+"Oh, I guess she means the major and some of the officers will come to
+see how we are situated, and to tell us more about--the big stunt," said
+Tom in English to his chum, assuming that "big stunt" would sufficiently
+disguise to any listening spies, if such there were, the real object
+that lay before them.
+
+"I suppose that's who she means," agreed Jack, as the landlady, who gave
+her name as Madame Reboux, withdrew.
+
+The boys were busy unpacking their few belongings, for they had not
+brought much to Paris, not intending to stay long, when they heard
+voices in the hall outside their room. And at the tones of a certain
+voice Tom and Jack started and looked at one another.
+
+"Listen!" exclaimed Tom.
+
+"If I wasn't afraid you'd say I was dreaming, I'd say I knew that
+voice!" murmured Jack.
+
+"I'd say the same," added Tom.
+
+"Who would you say it was?" his chum challenged.
+
+"Well, for a starter--"
+
+He paused, for the voice sounded more plainly now, and it said:
+
+"Yes, this is the right place, Mother. Oh, do you think the boys are
+here yet?"
+
+"It surely will be a pleasure to meet them again," said another voice,
+evidently that of a woman, the other having been a girl's.
+
+"I hope they won't have forgotten us," the girl went on, and at that
+Jack could no longer keep quiet. He rushed to the door, opened it, and
+cried:
+
+"Bessie! Is that you?"
+
+"Oh, it's Jack! Mother, here's Jack!" cried the girl, and she and her
+mother were soon shaking hands with Tom and Jack.
+
+"So, you two were the friends we were soon to see!" exclaimed Tom, as he
+placed chairs for Mrs. Gleason and her daughter. Or, to be exact, Tom
+placed a chair for the mother, while Jack got one for Bessie.
+
+"Yes, we were told you would be here," said Bessie's mother. "We did not
+know you were in Paris until we received word that it would be better
+for us to change our lodging and come here."
+
+"The same word we received," said Jack. "Say, it's working out mighty
+queer, isn't it, Tom?"
+
+"Yes, but very satisfactorily, I should say. Things couldn't be nicer.
+How have you been?" he asked, for he had not seen the girl nor her
+mother since the sensational rescue from the perfidious Carl Potzfeldt.
+
+"Very well indeed," answered Mrs. Gleason. "Both Bessie and I have been
+doing Red Cross work. But isn't that great German gun terrible? Oh, how
+it has killed and maimed the poor women and children! The Huns are
+fiends!"
+
+"I quite agree with you," said Tom, Jack meanwhile talking to Bessie.
+"But it isn't doing them the military good they thought it would, and,
+if all goes well, it may not very long do them any service at all."
+
+"You mean--" began Mrs. Gleason.
+
+But just then Bessie, who had arisen to go to the window to view the
+street, turned back with a start, and grasped Jack's hand.
+
+"Look! Look!" she whispered, and through the curtains she pointed to a
+man on the opposite side of the way.
+
+"Do you know him?" asked Jack.
+
+"Know him? Yes, to my sorrow."
+
+"Who is it?" asked Tom.
+
+"The spy!" exclaimed Jack. "The man we saw in the train, and the same
+fellow who tried to get into our lodgings. In spite of our precautions
+he has found out where we are."
+
+"I'm not so sure of that," said Tom. "He may not be here for any
+particular purpose. But do you know him too, Bessie?"
+
+"Yes," the girl answered. "He was in the château where mother and I were
+held prisoners by Potzfeldt. He is a tool in the pay of that spy, and a
+spy himself!"
+
+"Then we ought to do something!" exclaimed Jack, and he started to rush
+from the room.
+
+
+
+
+CHAPTER XIV
+
+WITH COMRADES AGAIN
+
+
+"Hold on! Wait a minute!" exclaimed Tom, as he caught hold of his chum.
+"Where are you going?"
+
+"Out to give warning to a policeman or to some army officer about that
+spy!" exclaimed Jack. "We know him to be such, and now, with Bessie's
+word that he was with Potzfeldt, it's enough to cause his arrest."
+
+"Yes, maybe it is," agreed Tom, who was a bit more cautious than his
+impetuous chum. "But if we do that we may spoil the plans of Major de
+Trouville. Better let matters take their course, Jack. That spy may not
+know we are here, and again, he may. But if he doesn't, rushing out now
+would be sure to give the secret away. As it is, there is a chance we
+may keep it."
+
+Jack, caught midway in his impetuous rush from the room, stood
+reflectively. What Tom had said to him appeared to make an impression.
+Then Bessie added her words of advice.
+
+"Yes, Jack," she said, "I think it would be rather rash to go out now
+and confront that man, or start a chase after him. I know I'm not as
+experienced as you two famous birdmen," she went on with a smile, "but
+I've been through some terrible experiences, as almost every girl has in
+this war zone, and I can do more thinking than I used to. Don't you
+think it would be wise to wait, Mother?"
+
+"Yes, Bessie," answered Mrs. Gleason, "I do. Our good friends in the
+military service who told us to come here, must have had some object.
+Perhaps it was connected with this same man who was so unkind to us in
+the château, and who was certainly a tool of that man I trusted once,
+but never will again--Carl Potzfeldt!" and she shuddered as she thought
+of what she had gone through.
+
+"Let him go," she said to Jack. "Perhaps it is just a coincidence that
+he is passing just as we arrive. Our departure from our last lodgings
+was made secretly."
+
+"So was ours," said Tom. "And yet I don't see how that spy found us so
+soon."
+
+"It is that which makes me think it is accidental," observed Mrs.
+Gleason. "It would be very unwise now to go out, I think."
+
+"All right, then I'll stay in," said Jack with a smile. "Especially as I
+have such good company. Tell me," he went on, "are you and your mother
+going to board here?" he asked Bessie.
+
+"Yes," answered Mrs. Gleason. "And though we were told we would meet
+friends here we could not guess it would be you brave boys."
+
+"Spare my blushes!" laughed Tom.
+
+"Same here," added Jack.
+
+"But what brings you to Paris?" asked Bessie. "I thought you boys were
+engaging in combats above the clouds."
+
+"We have been fighting, though not during the last two weeks," said Tom.
+"I had word that my father had come over here, but he never communicated
+with us, and we came to Paris to look him up. So far we haven't
+succeeded in finding him," and he gave the details of the visit of
+himself and his chum to the capital, telling of their first experience
+during the firing of the big gun.
+
+Bessie and Jack, who seemed to have much to say to one another, peered
+from behind the curtains out of the window now and then, and Jack at
+last reported that the spy had passed on, after stopping, apparently, to
+purchase some fruit at a stand on the street.
+
+"I don't believe he knew we were here," said Bessie.
+
+"Well, it won't do to take any chances," observed Tom. "However, we were
+not told to remain under cover, so I suppose we can go out when we
+like."
+
+"Better wait until we get some word from the major," suggested Jack, who
+was getting some of his chum's caution.
+
+All decided this was best, and the boys spent the rest of the afternoon
+in getting their room to rights, Mrs. Gleason and Bessie doing the same
+in their apartment. Mrs. Gleason had temporarily been relieved from Red
+Cross work to recuperate, she said, as she had been under a great
+strain.
+
+Toward evening Major de Trouville, or "Trouville," as he democratically
+liked to be called, arrived, and when told of the sight in the street of
+the spy, who turned out to be the same man who was one of the captors of
+Bessie and her mother, the officer said:
+
+"I am not surprised. In fact I rather looked for that, and it is one
+reason why I wanted to get you four together so you could see the man at
+the same time.
+
+"There is now no doubt as to his intentions, and the fact that he was
+here so soon after you arrived proves that there is a 'leak' somewhere.
+We suspected as much, and I think I know where it is. It is good
+information to have. Well, boys, did I surprise you?" he asked, smiling.
+
+"You did, indeed, but it was a pleasant surprise," said Jack.
+
+"But when are we going to be allowed to do something to silence that
+monster cannon?" asked Tom. "It's pleasant to be here, but we are not
+forgetting there is work to do."
+
+"Nor would I have you forget," said the major. "A number of persons were
+killed to-day by fire from the long-range gun. We believe, now, that
+there are two or three of them, as the shots come at closer intervals.
+It is imperative that something be done, and so I have brought you
+orders."
+
+"Good!" cried Jack.
+
+"That sounds like business!" commented Tom.
+
+"In regard to your father," went on the major, addressing Jack's chum,
+"we will be on the watch for him, or any news of him, and, no matter
+where you are, unless you are captured by the Germans, you shall be
+informed as soon as possible."
+
+"Is there any chance of being made prisoners?" asked Jack, and it might
+be noted that he did not use the word "danger."
+
+"There is always that chance for an airman," replied the major. "But
+when I add that it may be possible that one or both of you will take a
+flight over the Rhine, you can judge, with the hold Germany has on
+French possessions, what the danger is."
+
+"Over the Rhine!" exclaimed Tom. "Why, that's a flight of two or three
+hundred miles from Paris."
+
+"Yes, but with the new type of Italian plane which you may use, it is
+not impossible in a single flight," said the major. "However, we will
+talk of that later. Just now I have come to tell you that you are to
+rejoin your comrades at the Lafayette Escadrille for a time. There
+arrangements will be made for the perilous venture I spoke of--the
+silencing of the big guns that are bombarding Paris. I wish you all
+success, young gentlemen."
+
+"Thanks," murmured Jack.
+
+"We consider it an honor to be picked for such duty," added Tom. "Are
+any others going to be in the game?"
+
+"Oh, yes. We shall need a picked corps of the best airmen we have,
+French and Americans, and it will be no easy matter then. The Germans
+have probably been planning this for a long time, and they, no doubt,
+have taken every possible precaution against surprise or failure. But
+with the help of you brave Americans we shall win!"
+
+"That's right!" chimed in Bessie. "Oh, how I wish I were a man!" and she
+looked enviously at Jack and Tom.
+
+The major gave Bessie and her mother some instructions in regard to
+their actions should the spy come back, and then told Tom and Jack to
+prepare to leave Paris the next night.
+
+"Report to your former camp," he said, "and there you will find further
+instructions waiting for you."
+
+"Well, then as we have to-night, our last one free, let's go to some
+entertainment," suggested Tom to Bessie and her mother. "We can have
+supper afterward--not much of a celebration, for these are war times and
+it won't do to rejoice too much. But we ought to commemorate this
+meeting somehow."
+
+"That's right!" agreed Jack.
+
+So they went to a little play and had supper afterward in a quiet
+restaurant. That is, it was quiet until a sudden explosion a few blocks
+away announced the arrival of another German shell from the big gun, and
+then there was excitement enough.
+
+Fortunately, however, the shots did little beyond material damage, no
+one being killed. At the same time, however, there appeared some German
+planes over Paris, doubtless to observe the effect of the dropping of
+the long-distance shells, and naturally the French airmen went up to
+give them combat.
+
+The great searchlights began to play, picking out the hostile craft, and
+making them targets for the machine guns of the intrepid Frenchmen, and
+more than one Boche never got back over his lines again, while several
+Frenchmen found heroes' graves on the soil they had died to defend.
+
+"Oh, if we were only up there helping," said Tom, as he and his friends
+watched.
+
+"We shall be there very soon," murmured Jack. "And it can't be any too
+soon for me."
+
+The tide of battle turned in favor of the French, the Hun planes
+withdrawing as the fire got too hot for them. And soon after that the
+long-range gun ceased firing.
+
+It was rather a "pull" for Tom and Jack to say good-bye to Bessie and
+her mother in Paris, but they knew they had to do their duty. Nor would
+Mrs. Gleason and her daughter have kept the boys back for the world.
+They realized that the Air Service boys were helping to make the world
+safe for democracy, as they themselves were doing in their way.
+
+And so Tom and Jack, their mission to Paris, which was the discovery of
+Mr. Raymond, having failed, went back to the hangars, there to be
+welcomed by their comrades in arms.
+
+They arrived one morning, just after some planes from a bombing
+expedition over the German lines returned.
+
+"What luck?" asked Tom of a pilot with whom he had often flown.
+
+"The best, as regards the damage we did," was the answer. "We blew up
+several ammunition dumps, and put one railroad center out of business
+for a time. But Louis didn't come back," and the man turned aside for a
+moment.
+
+"You mean your brother?" asked Jack, softly.
+
+"Yes."
+
+"Perhaps he is only captured," suggested Tom.
+
+"No, his machine caught fire. They got his petrol tank. It's all up with
+him and La Garde. But we had our revenge. We sprayed the machine that
+got them until there was nothing left of it. And I'm going out again
+to-day in a Nieuport. They'll pay a price for Louis!"
+
+
+
+
+CHAPTER XV
+
+THE PICKED SQUADRON
+
+
+"All ready, Jack?"
+
+"Just a moment, Tom. I want to go over my struts and wires to make sure
+everything is taut. I don't want any accidents."
+
+"That's right. Got plenty of ammunition drums?"
+
+"All I can carry. I've got some tracer bullets, too."
+
+"That's good. Glad you reminded me of them. I must put in a stock. The
+last time I went up I wasted a drum before I got my man."
+
+Tracer bullets for aircraft guns, it might be observed, are balls of
+fire which enable the pilot to see the course his machine gun bullets
+are taking, so he may correct his fire.
+
+"Well, how about you now?" asked Tom, as he added these useful supplies
+to his ammunition.
+
+"I guess we're ready to start," replied Jack.
+
+They climbed into their machines, each pilot using a single-seat,
+swift-flying craft, equipped with a Lewis machine gun. The squadron was
+going out on patrol duty, and each pilot was to observe what he could
+behind the German lines, and come back to report--that is if he did not
+happen, as was too often the case, to be bagged by a German flier. The
+small, swift machines did not carry the wireless outfit, and no reports
+could be sent back to headquarters save those the pilot himself came in
+with.
+
+There was a rattle and a roar as the motors of the ten machines started,
+and then over the ground they went, "taxi fashion," to get the necessary
+speed to rise into the air. A moment later all went aloft, and were
+headed toward the German lines.
+
+Tom and Jack kept as close together as was safe, but it is dangerous for
+two aeroplanes to approach too closely. If they do, and are not under
+good control, there may be a suction created that will cause a
+collision.
+
+"Well, I hope I get one to-day," thought Tom, as he manipulated his "joy
+stick," so as to send his plane up on a sharp slant. "I want to make
+good, and then I'll have so much better chance to get after that German
+gun." And the same thought was in Jack's mind.
+
+The squadron was to remain aloft on a two-hour patrol, that is unless
+something should occur to make it advisable to remain up longer. The
+keen eyes of Tom and Jack, as well as those of their companions of the
+air, were searching for signs of the Hun planes. As yet none were in
+sight, but it would not be long before they would come out to give
+battle.
+
+Whatever else may justly be said about the Germans, their airmen are no
+cowards, and, when conditions are favorable, they seldom decline a
+chance to combat above the clouds, or lower down. So it could easily be
+guessed that when Tom, Jack and the others found themselves over the
+German lines that the Boches would be out in force.
+
+Somewhat off to the left Tom caught sight of a captive German balloon,
+looming through the mist, and as it is always the desire of a French
+flier to destroy one of these, thus preventing the observer from sending
+by wireless news of the Allied front, he started for this enemy. Jack
+saw his friend's act, and, desiring to aid, turned his machine in the
+same direction.
+
+But they had not gone far before they observed a number of black specks
+in the sky over the German lines.
+
+"The Huns are coming," reflected Tom. "Now for some hot work."
+
+And it came to him, to Jack, and the others, almost before they realized
+it. Tom never got a chance to attack the balloon he hoped to force to
+descend or to set on fire, for his attention was taken up by two German
+machines, which, separating from the others, headed straight for him.
+The lad gave one glance in the direction of Jack, and noted that a
+single Hun craft was about to engage with his chum.
+
+"It's a regular German circus," thought Tom, referring to the number of
+hostile craft. "They delight to go out in numbers."
+
+By this time the battle in the air had begun. It was a fight above the
+clouds, for both the French and the German machines were flying high,
+and had gone up above the bunches of fleecy vapor that now hid the
+ground from sight.
+
+Tom headed straight for one of the Hun machines, seeking to get above
+it, always a point of vantage in an air battle, and as he rushed on he
+realized that his machine was being hit by bullets from one of the Hun
+guns.
+
+Each bullet, as it struck, made a loud noise, as it punctured the
+tightly-drawn linen that covered the wings. But Tom knew that his craft
+could stand a number of such holes, if only the struts, the supports,
+and the guy wires were not broken. He had no time, now, to note what
+Jack or his comrades were doing, for his whole attention was taken up
+with the two Hun machines engaging him.
+
+One seemed to be more skillful than the other, and to this one Tom gave
+his attention first. He emptied a stream of bullets full into this
+flier's craft, noting, after the first few bad shots, which he could
+tell by the tracers, that he had perfect range.
+
+Guiding his craft with one hand and his feet, Tom worked the Lewis gun
+with his other hand, and he had emptied a whole drum at the daring Hun
+before he had the satisfaction of seeing the machine crumple up. Tom's
+bullets had struck some part that had caused the wings to collapse, and
+the airman went down to earth, his craft out of control.
+
+But matters were not to go easy with the American. The other German was
+now in a better position for getting Tom than the latter was for potting
+him, and Tom felt a stream of bullets flying around him. One chipped his
+gun, and another grazed his cheek, the close call making his heart stand
+still for a moment. But he never faltered.
+
+"I've got to get above him," Tom thought fiercely.
+
+He made a risky spiral turn to one side, and began to mount, seeking to
+get in position to fire to better advantage. It was touch and go for a
+while, and he felt, rather than heard, his craft receive several
+bullets.
+
+"If only the gasolene tank isn't hit," thought Tom.
+
+But good fortune in this respect was with him, and he got in a position
+where he could point his machine (and the gun at the same time, for this
+is how the guns are aimed in the single aircraft) at the Hun flier. And
+then Tom sent forth a rain of bullets.
+
+For a moment they seemed to have no effect, and yet Tom knew he had shot
+straight. Then, even while he felt a sharp pain in one hand, showing
+that he had been hit, he saw the other machine start down in a spinning
+nose dive. That meant he was going downward head first, and at the same
+time spinning around like a top.
+
+This spinning nose dive may be intentional or accidental--that is, with
+the machine in control, or out of control. The spinning nose dive was
+discovered by accident, but is now part of the regular flying features,
+and is often used by aviators to escape from an enemy.
+
+It is almost impossible to hit a plane doing a spinning nose dive, and
+if an aviator is over his own lines he may be able to come out of it
+before he reaches the ground, and so be safe. Many German planes have
+escaped in this way, and often a French airman has thought he has sent
+his enemy down disabled, when, as a matter of fact, the other has merely
+adopted this ruse to get away.
+
+"Well, I don't know whether I got him, or whether he got frightened and
+went down to fool me," thought Tom. "Anyhow they're both out of the way,
+and I can go after the balloon."
+
+But Tom could not, for two reasons. One was that the wound in his hand
+was bleeding profusely, and he knew it ought to be attended to before he
+was incapacitated. Another was that the balloon was being hauled down,
+and as more French planes were in the air now, making a number superior
+to the Huns, the latter turned tail and retreated.
+
+It was inadvisable to follow them over their own lines now, and the
+squadron, or what was left of it, began to retreat. Tom noted the
+absence of three of the French planes, and among the missing was Jack's.
+
+"I wonder if they got him," Tom mused, his heart becoming like lead. His
+eyes sought the air about him, but Jack's machine, which carried a
+little United States flag where it could easily be seen, was not in
+sight.
+
+It was impossible to get any information up in the air. Tom would have
+to wait until they got back to the aerodrome. And he put on speed to get
+there the sooner, in order to end his suspense.
+
+"And the other brave fellows--I wonder what happened to them," mused
+Tom. In his worry over the fate of Jack and the others he scarcely
+minded the pain in his hand.
+
+He made a good landing, but being rather weak and faint from loss of
+blood, he scarcely heeded the congratulations of his comrades, who had
+received word, by telephone from the front, of the fate of some of the
+Hun machines. "Where's Jack?" Tom gasped, while a surgeon was putting a
+bandage on his hand.
+
+"Right here, old scout!" came the unexpected answer, and Jack himself
+stepped out from amid a throng of airmen. "Why didn't you wait for me?"
+Jack went on. "I was coming back."
+
+"Coming back? Did you come down safely?" asked Tom, beginning to feel a
+little better now. Then Tom realized the futility of his question, for
+was not Jack there in the flesh?
+
+"Of course I came back, old scout," was the answer. "I had hard luck,
+though, but I'd have gone up again if they'd only waited for me."
+
+"What happened?" asked Tom.
+
+"Oh, just after I potted my man--or at least sent him down out of
+control--I got a bullet through my gasolene tank. Luckily it didn't set
+the petrol on fire, but I knew I'd better not take any chances. I tried
+to plug up the puncture with some chewing gum, but it wouldn't work.
+Guess the gum they sell now hasn't as much old rubber boot stock in it
+as it used to have. Anyhow it was leaking like a sieve, and I had to
+head for our lines."
+
+"Tough luck!" consoled Tom. Jack did not add that he had, as soon as he
+landed, got into another machine, and was about to go back and join his
+comrades when they returned, having practically won the battle above the
+clouds.
+
+Congratulations were extended to the members of the squadron, who
+accepted their honors modestly enough, as was characteristic of them.
+
+Then, after Tom's wound had been dressed, and he and Jack were talking
+over the events of the day, there came a communication from the
+commander of the air division in that sector. It was an order calling on
+certain men to report at once for special duty. A picked squadron was to
+be detailed for a hazardous enterprise, it was said.
+
+"And our names are there!" cried Jack. "Tom, old man, we're going!"
+
+"But where is it?" asked another American flier named Boughton. "What's
+the game?"
+
+Knowing the secret would be safe with him Tom said:
+
+"We're going to pot the big German cannon that's bombarding Paris!"
+
+
+
+
+CHAPTER XVI
+
+MISSING
+
+
+News of the shelling of Paris by the long-range gun had, of course, been
+received at the aerodrome, though there had not, as yet, many details
+come in. Tom and Jack, as the latest arrivals from the big city, were
+called upon to tell all they knew, and they related their experiences in
+the raids, and also told about the various theories of the big gun.
+
+"But how are we going to find it?" asked. Boughton. "It's easy enough,
+of course, for our squadron to go out with a lot of bombs. But where are
+we going to drop 'em?"
+
+"Oh, we're to go to Paris for further instructions before starting on
+the quest," said Tom, who had made some inquiries about the orders
+concerning the picked squadron.
+
+"And they may have discovered its location by this time," added Jack.
+"We know about where it is--somewhere in the sector between Hamegicourt
+and Condé. The rest ought to be easy."
+
+"Not so easy as it sounds, my friends," put in a French flier. "I know
+that region. It is a big one; and the Germans no doubt have their gun
+well camouflaged. It will not be easy."
+
+"But we'll get it!" asserted Tom.
+
+"Naturally," said the Frenchman, as if that was all there was to it.
+
+Tom's wound was painful, but not dangerous, though it would keep him on
+the ground for a day or two. Though, as a matter of fact, none of the
+members of the picked squadron was allowed to go aloft after the orders
+came detailing them for work in connection with the monster cannon.
+Their places were taken by others who were sent for, some being new
+fliers who were burning to make a name for themselves.
+
+Besides Tom and Jack, in the picked squadron there were Boughton,
+another American, Cerfe and Tierse, two intrepid Frenchmen, and Haught,
+an Englishman, who insisted, but with little success, that his name be
+pronounced as though spelled "Hoo."
+
+These six were to be depended on to find and destroy the German
+cannon--all of them if there were more than one, as was likely. And to
+this picked squadron other members would be added as need arose. All six
+were skillful fliers, and brave men of the air, as may easily be
+guessed. They were to use whatever type of machine they liked best--the
+single seaters, the great bombing planes, and, it was even said, one of
+the immense Italian fliers. This last was a craft capable of carrying
+several men and a quantity of supplies and ammunition.
+
+Very soon, then, Tom Raymond and Jack Parmly were on their way to Paris
+again, accompanied by their comrades, and all would soon be engaged in
+the difficult and perilous task of finding the new German long-range
+cannon.
+
+"I suppose you'll make another attempt to find your father?" suggested
+Jack to his chum, as they rode in on the train.
+
+"Indeed I shall, if I have time. I can't understand why I haven't had
+some word before this. There are several possible reasons, of course. If
+it wasn't that we know he got to Rue Lafayette I'd say his ship had been
+sunk 'without a trace,' as the Germans ordered in other cases. But, of
+course, he safely reached this side. Then he just seems to have dropped
+out of sight, for I can't believe he was killed when the shell from the
+big gun hit the house where he had taken lodging. He may have found it
+advisable to return home at once, for some reason, and didn't have a
+chance to leave any word for me, or send me any message. And perhaps he
+hasn't got back to America yet. Then, too, he may be in Germany, a
+prisoner."
+
+"Let us hope not," said Jack, softly, and Tom echoed the wish.
+
+Much as he wished he could devote some time to the search for his
+father, Tom realized that he was working under military orders, and,
+however dear his father was to him, the sacrifice of his personal
+affairs must be made. He knew he would only have time to make some brief
+inquiries, and then he and Jack must go with the squadron to the
+headquarters assigned to it, as near the location of the big German gun
+as possible, and there try to silence it.
+
+The train the picked squadron was traveling on was late, and it was dusk
+when they alighted at the railroad station.
+
+"Think we'll have a chance to see anything of the bombardment?" asked
+Boughton.
+
+"I was going to say I hoped not," answered Tom, "for I wish the beastly
+gun, or guns, would blow up. But that would take away our chance to pot
+'em, and I know we all want to do that. You may see something, though
+they don't bombard at night as often as they do by day. Of late,
+however, before we left, the night firing was more frequent. Possibly
+they have found some means of hiding the gun flashes or of letting them
+mingle with others along a line so the exact location of the big Bertha
+is a matter of doubt."
+
+As they alighted from the train, and were about to seek some taxicabs to
+take them to lodgings that had been assigned them, they all became aware
+of the fact that something unusual was going on. Suddenly the electric
+lights went out, leaving the region about the station, and indeed all of
+Paris, in comparative darkness.
+
+At the same time a motor fire engine rushed screeching through the
+streets, giving an alarm.
+
+"What is it?" cried Boughton. "Is the big gun firing?"
+
+"It's a Zeppelin raid! I was here once before when they had one," said
+the Englishman coolly. "Mind your heads, boys. Just our rotten luck not
+to have a machine to go up after it."
+
+He hurried out into the open street where he could have a view of the
+sky, and the others followed. There was more excitement than during the
+bombardment of the big gun. People were rushing here and there in search
+of safe places, and taxicabs, with their lamps like fireflies in the
+darkness, were skidding hither and yon, their horns calling for a clear
+way.
+
+Suddenly there was a muffled roar, at some distance off. This was
+followed by a hoarse murmur, as though a burst of rage from many throats
+at the unspeakable outrage of the Huns in killing women and children.
+
+At the same time the anti-aircraft guns, with which Paris is so
+efficiently guarded, began to bark and to send their red flashes out
+into the blackness of the night. They were shooting at the Zeppelin, as
+yet unseen by the men of the picked squadron, and the gunners aimed
+according to instructions sent them by wireless from scouts hovering in
+the air above the city.
+
+As soon as word comes from the front, about eighty miles from Paris,
+that a Zeppelin is on its way to raid, an elaborate system of defense is
+put into operation. There are some airmen above Paris all the while,
+frequently as many as forty on sentry duty. But when word comes of a
+Zeppelin raid the whole squadron, numbering close to three hundred, goes
+aloft. By their searchlights, aided by those on the surface, these
+fliers endeavor to pick up the German machine, and, too, they endeavor
+to get near enough to attack it.
+
+This was what was now going on. Pandemonium appeared let loose, and the
+explosion of the German bombs, mingling with the noise of the French
+guns, made Paris seem like a battlefield. Occasionally could be heard,
+when the guns were silenced for a moment, the roar of the many aeroplane
+motors aloft.
+
+The Zeppelin seemed to be over a section of Paris near the Tuileries,
+judging by the bursts of light in that direction. Tom, Jack, and their
+friends wished with all their hearts that they might take a hand in the
+defense, but it was not to be. For perhaps half an hour the
+anti-aircraft guns roared out their defiance to the Hun, and then a
+large flare of gasolene was lighted in a public square.
+
+This was a signal for the aeroplanes to return, for the Zeppelin had
+left, either because she found the situation too perilous for her, or
+because she had used up all her bombs.
+
+The lights were turned on again, and the new arrivals watched the
+aeroplanes returning one by one, being recognized by their lights in the
+air as they moved about like gigantic illuminated insects.
+
+"Well, that's some excitement," observed Tom, as he and the others
+finally succeeded in getting cabs, and started for their destination. "I
+hope no one was killed."
+
+But the bombs of the inhuman Huns had found several marks, and while the
+harm from a military standpoint was small, a number of persons had been
+killed. Some damage had been inflicted on the Zeppelin, it was said
+later, one brave airman saying he got near enough to spray some bullets
+into one of the cabins where a crowd of officers and men were working
+the machine.
+
+"We will be with you a little later," said Tom to the other members of
+the squadron, as, having reached their lodgings, the two chums set out.
+
+"Where are you going?"
+
+"To call on some ladies," answered Jack, for he and Tom had planned to
+see Bessie and her mother.
+
+They reached their own former stopping place, to which they had been
+sent by Major de Trouville, but when they inquired for the Gleasons the
+landlady, who remembered the boys, stared at them in surprise, and said:
+
+"Why, Madam Gleason and her daughter are not here! They went out this
+morning to meet you, and have not come back!"
+
+"To meet us?" gasped Jack.
+
+"Yes, in answer to your note bidding them do so!"
+
+
+
+
+CHAPTER XVII
+
+SEEKING THE GUN
+
+
+Tom and Jack gazed blankly at one another. The same thought was in the
+minds of both.
+
+"The spy!"
+
+"That's who did it," declared Tom. "He forged our names to a note--no
+hard task since neither Bessie nor her mother knows our writing very
+well--and he's induced them to go some place where he could get them in
+his power again."
+
+"But why?" asked Jack.
+
+"Probably because Potzfeldt wanted him to do it. He still has his eye on
+Mrs. Gleason's property, I presume, if there is any left after his
+robbery."
+
+"It certainly is tough to think that Bessie and her mother have again
+fallen into his clutches!" exclaimed Jack. "And we can't do a thing to
+rescue them. We've got to report with the others in the morning at the
+new aerodrome."
+
+"Yes, but we still have to-night free!" cried Tom. "It will give us
+several hours to make a search, and we'll do it! Do you know where Mrs.
+Gleason and Bessie went in response to this forged note?" he asked the
+landlady.
+
+She mentioned a certain restaurant, not far away, where Tom and his chum
+had frequently eaten with Mrs. Gleason and her daughter.
+
+"She was rather surprised to get the note from you," said the landlady,
+"and wondered why you didn't come yourself. But she supposed it had
+something to do either with your search for your father or with war
+matters, so she did not question the messenger. I heard her mention the
+place where she and Bessie were going, or I would not know."
+
+"How long ago was it?" asked Jack.
+
+"Oh, just before luncheon time. And they haven't come back."
+
+"The scoundrels have a long start of us!" exclaimed Jack. "We'll have to
+do the best we can."
+
+"Better notify the police at once," suggested Tom. "We'll need their
+help."
+
+"That's right," agreed his chum.
+
+Their uniform was an open sesame to the police officials, and a
+detective was at once detailed to go with the boys to the restaurant.
+There, as might have been expected, there was no news. The spy, or
+whoever Potzfeldt's agent was, had been too clever for that. All that
+could be learned from a taxicab driver was that a lady and a girl,
+answering the descriptions of Bessie and her mother, had been met in
+front of the restaurant by a man.
+
+The three, after a short talk, had driven off together in an automobile,
+and that was the last seen of them.
+
+"But we'll get some trace," declared the detective. "It is hard to get
+in or out of Paris now without proper papers. And while, of course, this
+spy may have forged documents, there is a chance that we may intercept
+him and help your friends. Time is against us, but we will do our best."
+
+Tom and Jack knew that. There was nothing else to do, and so, worried as
+they were, they went back to their comrades. Tom made some inquiries
+about his father, but, as he feared, no news had come.
+
+As may be imagined Tom and Jack did not pass a very restful night. The
+Zeppelin raid had set their nerves on edge, as well as those of every
+one else, and it could not be told when the big gun might begin firing
+again. Then the fact of Mrs. Gleason and Bessie being missing, and not
+knowing in what danger they might be, added to the boys' anxiety.
+
+They paid a late visit to the police, hoping for news, but the spy had
+not been apprehended. Then they hurried back to get a little rest
+before starting with their comrades of the air to search for the monster
+gun.
+
+While these events were transpiring, the French army intelligence
+department had not been idle. The officials knew how vitally necessary
+it was, in order not to have the morale of the people of Paris weakened,
+to do something to find and silence the big guns. And first it was
+necessary to discover them.
+
+While this, as yet, had not been done with exactness, owing to the
+concealing tactics of the Germans, it was believed that the long-range
+cannon was hidden in a certain wood near Laon. French airmen had
+endeavored to spy out certain positions there, but an unusually large
+number of German planes had fought them off.
+
+"That's pretty good evidence that there must be something doing,"
+observed Tom, when he heard this information. "Laon is about ten miles
+behind the German lines as they exist at present. Just a breather for a
+good French plane. Jack, that's a trip we'll soon be taking."
+
+"I'll be with you, old scout. How's your hand?"
+
+"Oh, all right now. I can hold the joy stick or work the gun. I'm ready
+for whatever comes along."
+
+The time had come for the picked squadron to leave Paris and assemble
+at the aerodrome assigned to them as their headquarters while the search
+for the big gun was in progress. Sad at having to leave without having
+some word of Mr. Raymond, and without knowing the fate of Bessie and her
+mother, Tom and Jack, nevertheless, bore up well and left with their
+comrades, going out of Paris on a train that would eventually bring them
+to their headquarters.
+
+In a way their mission was a secret one. Yet it was a question if the
+Germans did not guess that something like what really was afoot would be
+undertaken in order to silence the super-cannon. They were up to all the
+tricks of war, and they must have realized that the French would do as
+the Germans themselves would do under similar circumstances.
+
+"Well, this sure is some place!" exclaimed Tom, as they reached the camp
+where they were to stay until the gun had been destroyed, or until some
+other change in plans was necessary. "It's the best aerodrome we've
+struck since we began flying in this war."
+
+"I believe you!" echoed Jack.
+
+The place, though newly established just back of the French lines, where
+they opposed the German trenches, was well fitted up for the purpose to
+which it was to be devoted.
+
+There were a number of canvas hangars for the aeroplanes, there were
+living quarters for the men, a wireless station and a well defended camp
+where the aviators might live in comfort during the periods between
+their flights.
+
+Of course the place was open to attack by German fliers, but this was
+true of every place along the line. Sufficient camouflaging had been
+done, however, to render the spot reasonably secure from bombing. Of
+course a direct attack from in front would be met by the admirable
+French system of defense, and there were plenty of reserves that could
+be brought up if a general advance were attempted by the Germans. But as
+there was no particular place of any military or strategic importance on
+that sector, the worst that was to be feared was an attack from the air.
+
+And this would be guarded against both by the French fliers themselves
+and by a battery of the newest type of anti-aircraft gun.
+
+"They don't seem to have forgotten much," observed Tom, as he and Jack,
+with the others, went to the quarters assigned to them.
+
+"You said something!" exclaimed Jack, admiringly.
+
+Thus had been set up in this locality, where heretofore no aircraft
+activities had been carried on to any extent, a most perfect
+escadrille.
+
+It was designed to destroy the big German cannon. Would it succeed?
+
+That was a question every man of the Allies asked.
+
+Shortly after the arrival of the picked squadron at the camp, which, in
+honor of Tom and Jack had been named "Lincoln," word came in over the
+wireless that the big gun had again fired on Paris.
+
+"It's funny we didn't hear any report of it," said Jack.
+
+"There have been reports enough," Tom remarked. "I've heard the booming
+of distant guns ever since we got near this place. Any one of them may
+have been the monster, or they may have been firing other guns to hide
+the sound of this cannon. Then, too, it may not make as much noise as we
+think it ought to. The Germans may have found a new kind of powder, or
+even some propelling gas, that makes no extraordinary report. In that
+case we couldn't locate the gun by the sound."
+
+"Maybe you're right," agreed Jack. "Anyhow they're firing, that much is
+proved; and it's somewhere over there," and he motioned toward the
+German lines.
+
+Much as the airmen desired to start at once in their search for the
+monster cannon, it was deemed wise to have first a consultation and a
+general understanding of what means should be employed.
+
+Then, too, all the aircraft were new, having been shipped to Camp
+Lincoln and there assembled, and it was desired to test them before
+taking the dangerous flights over the German lines. So the airmen would
+have to spend some time--perhaps half a week--in preliminary work.
+
+Meanwhile the great cannon would keep up its deadly, though, from a
+military standpoint, useless work.
+
+And so began the preparation, if such it might be called. Every one,
+from the most daring "ace" to the humblest kitchen helper in the camp,
+was anxious for the day when it could be said that the gun was out of
+commission, or guns, if, as was likely, there was more than one. But the
+men in command knew the value of thoroughness. There must be no failure
+through lack of making proper plans.
+
+But at last everything was in readiness. The planes had been tested,
+keyed up, and the motors run until every part of them was humming like a
+top. Each man felt confidence, not only in himself but in his craft, and
+that meant much. There were several types for the fliers to use,
+single-seaters, the big bombing craft, those equipped for slow flying
+and from which photographs were to be taken, as well as others. The
+taking of photographs was expected to help in revealing the position of
+the hidden gun.
+
+The big Italian plane was not ready, it seemed, to be used, but it would
+be soon, it was said.
+
+Then came the day and the hour when certain members of the picked
+squadron were to take the air to look for the gun. Tom and Jack, to
+their delight, were selected to go.
+
+"What a chance!" exclaimed Jack, as he climbed into his machine, and saw
+that he had plenty of ammunition for the Lewis gun.
+
+"I hope we can make good!" returned Tom.
+
+Then they were away and up, seeking to find the monster cannon that was
+bringing the war into the heart of Paris.
+
+
+
+
+CHAPTER XVIII
+
+A CLOUD BATTLE
+
+
+For some little time the picked squadron that was intrusted with the
+difficult and dangerous task of locating the big German gun flew over
+the French lines. Below them Tom and Jack could make out various French
+camps, the front and supporting lines of trenches, and various other
+military works. They could see a brisk artillery duel going on at one
+point. They noted the puffs of smoke, but of course could not hear the
+explosions, as their own motors were making too much noise.
+
+Tom and Jack kept within sight of one another, and also within view of
+their comrades. Each plane was marked with a big number so it could be
+distinguished, for the aviators themselves were so wrapped in
+fleece-lined clothes, so attired in gauntlets, goggles and fur boots, as
+protection against the terrible cold of the upper regions, that one's
+closest friend would not recognize him at a near view.
+
+It was the object of this first scouting expedition to make a
+preliminary observation over as wide a range of the enemy's country as
+possible. While it was hoped that the location of the big gun might be
+spied out, it was almost too much to expect to pick out the spot at the
+first trial. The Germans were keen and wary, and undoubtedly they would
+have laid their plans well.
+
+"Well, I don't see any of 'em coming out to dispute our passage,"
+thought Tom, as he looked at his controls and noted by his height gage
+that he was now up about two miles. "There isn't a Boche plane in
+sight."
+
+And the same thing was observed by Jack and the other fliers. The
+Germans seemed to be keeping down, or else were higher up, or perhaps
+hidden by some cloud bank.
+
+That was another hazard of the air. Going into a cloud, or above it
+might mean, on coming out, that one would find himself in the midst of
+enemies.
+
+It is a life full of dangers and surprises. It is this which makes it so
+appealing to the young and brave.
+
+On and on flew the Allied planes, and the eager eyes of the pilots were
+alternately directed toward the earth and then ahead of them, and upward
+to discern the first sight of a Hun machine, if such should venture out.
+
+The fliers were now well over the German lines, and the batteries from
+below began firing at them. This was to be expected, and Tom, Jack and
+the others had gotten used to the bursts of shrapnel all around them.
+They could see the puffs of smoke where the shells burst, but they could
+hear no sounds.
+
+"The 'Archies' are busy this morning," thought Jack, as he noted the
+firing from below, and using the French slang word for the German
+anti-aircraft guns.
+
+He took a quick glance toward Tom's machine to make sure his chum, so
+far, was all right. Assured on this point Jack looked to his own craft.
+
+"Well," he mused, "at this point the 'flaming onions' can't get us, but
+they may pot us as we go down, as we'll have to if we want to get a good
+view of the ground where the big gun may be hidden."
+
+The "flaming onions," referred to by Jack, were rockets shot from a
+ground mortar. They have a range of about a mile, and when a series of
+them are shot upward in the direction of a hostile plane it is no easy
+matter for the aviator to pass through this "barrage." Once a "flaming
+onion" touches an aeroplane the craft is set on fire, and then, unless a
+miracle happens, the aviator falls to his death.
+
+The German gunners, however, could not use these to advantage while the
+French planes kept so high up, though the shrapnel was a menace, for
+the Hun guns shot far and with excellent aim. A number of the scout
+machines were hit, Tom's receiving three bullets through the wings,
+while Jack's engine was nicked once or twice, though with no serious
+damage.
+
+But as for the German planes they declined the combat that was offered
+them. Probably they had different plans in view. It soon became evident
+to Tom, Jack and the others that to fly at that height meant discovering
+nothing down below. The distance was too great. The big gun might be
+hidden almost anywhere below them, but until it was fired, disclosing
+its presence by an unusual volume of smoke, it would not be discovered.
+Also its fire might be camouflaged by a salvo from a protecting battery.
+
+"It's about time he did that," said Tom to himself at last, as he
+noticed Cerfe, who was the leader of the air squadron, dip his plane in
+a certain way, which was the signal for going down. "We've got to get
+lower if we want to see anything," the young aviator went on. "Though
+they may pot some of us."
+
+Down they went, flying comparatively low but at great speed in order to
+offer less of a target to the gunners below them. And, following
+instructions, each pilot noted carefully the section of the German
+trenches beneath him, and the area back of them. They were seeking the
+big gun.
+
+But, though they looked carefully, it could not be seen, and finally
+when one of the French machines was badly hit, and the pilot wounded, so
+that he had to turn back toward his own lines, Cerfe gave the signal for
+the return.
+
+In all this time not a Hun plane had come out to give battle. What the
+reason for this was could only be guessed at. It may have been that none
+of the German machines was available, or that skillful pilots, capable
+of sustaining a fight with the veterans of the French, were not on hand
+just then. However that may have been, Tom, Jack and the others, after
+firing a few rounds from their machine guns at the trenches, though
+without hope of doing much damage, turned back toward Camp Lincoln.
+
+"Well, then you did not discover anything?" asked Major de Trouville,
+who had been transferred and given the command at Camp Lincoln.
+
+"Nothing," answered Jack.
+
+"If it's in the section we covered, it is well hidden," added Tom.
+
+"And I think, don't you know," went on the Englishman, Haught, "that the
+only way we'll be able to hit on the bally mortar is to fly low and take
+photographs."
+
+"That's my idea," said the major. "If we take a series of photographs
+we can develop them, enlarge them, if necessary, and examine them at our
+leisure. I had thought of this, but it's a slow plan, and it
+means--casualties. But I suppose that can't be avoided. But I wanted to
+try the scouting machines first.
+
+"After all, the taking of photographs from the air of the enemy trenches
+and the land behind them is a most valuable method of getting
+information," he continued.
+
+Men, specially trained for such observation work, examine the
+photographs after the aviators return with the films, and they can tell,
+by signs that an ordinary person would pass over, whether there is a new
+battery camouflaged in the vicinity, whether preparations are under way
+for receiving a large number of troops, or whether a general advance is
+contemplated. Then measures to oppose this can be started. So, Major de
+Trouville was right, photography forms a valuable part of the new
+warfare.
+
+The photographing of the enemy positions is done in big, heavy machines,
+carrying two men. They must fly comparatively low, and have not much
+speed, though they are armed, and it takes considerable of an attack to
+bring them down. But of course the pilot and his observer are in danger,
+and, to protect them as much as possible, scout planes--the single-seat
+Nieuports--are sent out in squadrons to hover about and give battle to
+the German aircraft that come out to drive off the photographers.
+
+"We'll undertake that," proceeded Major de Trouville. "I'll order the
+big machine to get ready for an attempt to-morrow at locating the gun."
+
+"Is it still shooting?" asked Jack.
+
+"Yes, it has just been bombarding Paris; but I have no reports yet as to
+the damage done."
+
+"Aren't we doing anything at all?" asked Tom.
+
+"Oh, yes, our batteries are keeping up a fire on the German lines along
+the front behind which we think the gun is concealed, but what the
+results are yet, we don't know."
+
+"Well, let's hope for clear weather to-morrow," suggested Boughton.
+
+The intervening time was occupied by the aviators in getting everything
+in readiness. The machines were inspected, the automatic guns gone over,
+and nothing left undone that could be thought of to give success.
+
+The next day dawned clear and bright, and, as soon as it was light
+enough to make successful photographs, the big machine set out, while
+hovering above and to either side of it were several Nieuports. Tom and
+Jack were each occupying one of these, ready to give battle to the Huns
+above or below the clouds.
+
+In order to distract the attention of the Germans as much as possible
+from the direct front where the airships were to cross the lines, a
+violent artillery fire was maintained on either flank. To this the
+Germans replied, perhaps thinking an engagement was pending. And so,
+amid the roar of big guns, the flying squadron got off.
+
+"Now we'll see what luck we'll have," mused Tom, as he drove his machine
+forward, being one of the large aerial "V" that had for its angle the
+ponderous photographing bi-motored machine.
+
+Over the German lines they flew, and then the Germans awoke to the
+necessity of ignoring the fire on their flanks and began shooting at the
+airships over their heads.
+
+"This ought to bring out their pilots if they have any sporting blood,"
+thought Jack.
+
+And it did. The French and their allies were no more than well over
+German-occupied territory, before a whole German air fleet swarmed up
+and advanced to give battle. They flew high, intending to get above
+their enemies, and so in the most favorable fighting position. But Tom,
+Jack and the others saw this, and also began to elevate their planes.
+
+"We certainly are going up!" mused Tom, as he noted the needle of his
+height gage showing an altitude of twelve thousand feet. "When are they
+going to stop? We're high above the clouds now."
+
+That was true as regarded himself, Jack, and two other French planes.
+But still the Germans climbed. Doubtless some of them were engaging the
+big machine which was low down, trying to take photographs, but Cerfe
+and Boughton were guarding that.
+
+"Here comes one at me, anyhow!" thought Tom, as he saw a Hun machine
+headed for him.
+
+"Well, the sooner it's over the better. Here goes!" and he pressed the
+release of his automatic gun, meanwhile heading his craft full at the
+German to direct the fire, for that is how the guns are aimed in a
+Nieuport, the gun being stationary.
+
+And so began the battle above the clouds.
+
+
+
+
+CHAPTER XIX
+
+QUEER LIGHTS
+
+
+Tom Raymond's first few shots went wild, as he noted by the tracer
+bullets. Then, steering his machine with his feet, he brought it around
+a trifle, and, having by a quick action risen above his antagonist, he
+let him have a good round, full in the face. The result was disastrous
+to the German, for suddenly the Hun machine burst into flames, the
+gasolene from the punctured tank burning fiercely, and down it went a
+flaming torch of death.
+
+Tom felt some bullets whistle around him, and one exploded as it struck
+part of his engine, but without injuring it.
+
+"Explosive bullets, are they?" mused the young aviator. "Against all the
+rules of civilized warfare. Well, he won't shoot any more," he thought
+grimly.
+
+But though Tom had come victorious from his engagement with his single
+antagonist, he had no sooner straightened out and begun to take stock of
+the situation, than he became aware that he was in great danger. Above
+him, and coming at him with the swiftness of the wind, were two speedy
+German machines, bent cm his destruction.
+
+They were both firing at him, the angles of attack converging, so that
+if one missed him the other would probably get him.
+
+"I've got to get out of this," Tom reasoned. He headed his plane toward
+the antagonist on his right, shooting upward and firing as rapidly as he
+could, and had the satisfaction of seeing the German swerve to one side.
+The fire was too hot for his liking.
+
+The other, however, came on and sent such a burst of fire at Tom that
+the latter realized it was a desperate chance he was taking. He tried to
+get above his enemy, but the other's plane was the speedier of the two,
+and he held the advantage.
+
+Tom's ammunition was running low, and he realized that he must do
+something. He decided to take a leaf out of the book of the Germans.
+
+"I'll go down in a spinning nose dive," he reasoned. "They'll be less
+likely to hit me then. I'll have to go back, I guess, and get some more
+shots. I used more than I thought."
+
+He sent his last drum at the persistent German, and, noting that the
+other was swooping around to attack again, went into the dangerous
+spinning nose dive.
+
+The Germans may have thought they had disabled their antagonist, for
+this dive is one a machine often takes when the pilot has lost control.
+But in this case Tom still retained it, and when he had dropped out of
+the danger zone, he prepared to straighten out and fly back over his own
+lines.
+
+It is not easy to straighten an airplane after such a dive, and for a
+moment Tom was not sure that he could do it. Often the strain of this
+nose dive, when the machine is speeding earthward, impelled not only by
+its propellers, but by the attraction, of gravitation, is so great as to
+tear off the wings or to crumple them. But after one sickening moment,
+when the craft seemed indisposed to obey him, Tom felt it beginning to
+right itself, and then he started to sail toward the French lines.
+
+He was not out of danger yet, though he was far enough away from the two
+German machines. But he was so low that he was within range of the
+German anti-aircraft guns, and straightway they began shooting at him.
+
+To add to his troubles his engine began missing, and he realized that it
+had sustained some damage that might make it stop any moment. And he
+still had several miles to travel!
+
+But he opened up full, and though the missing became more frequent he
+managed to keep the motor going until he was in a position to volplane
+down inside his own lines, where he was received with cheers by his
+comrades of the camp.
+
+"How goes it?" asked Major de Trouville anxiously.
+
+"I think we are holding them off," said Tom.
+
+He was the first one who had had to return, much to his chagrin. He
+leaped out of his craft, and was about to ask for another to go back and
+renew the battle of the clouds, when he saw the big photographing
+machine returning, accompanied by all but two of the escorting craft.
+
+"A pair missing," murmured the major, as he searched the sky with his
+glasses.
+
+And Tom wondered if Jack's machine was among those that had not headed
+back.
+
+Eagerly he procured a pair of binoculars, and when he had them focused
+he identified one machine after another, at last picking out his chum's.
+It did not seem to be damaged.
+
+But two of the French craft had been brought down--one in flames, the
+report had it, and the other out of control, and both fell within the
+German lines.
+
+"Did you get any photographs of the big gun?" asked the major, when the
+men in the double machine had made a landing.
+
+"We got lots of views," answered the photographer, "but what they show
+we can't say. As far as having seen the gun goes, we didn't spot it."
+
+"Well, maybe the photographs will reveal it," suggested the major. "Ah,
+but I am sorry for the two that are lost!"
+
+Jack's experience had been less exciting than Tom's. One machine had
+attacked the former, and there had been a hot engagement for a while,
+but the German had finally withdrawn, though to what extent he was
+wounded or his machine damaged Jack did not know.
+
+However, the picked squadron had reason to feel satisfied with their
+efforts. All now depended on the developing of the photographs, and this
+was quickly done. For this part of warfare is now regarded as so
+important that it is possible for a plane to fly over an enemy's
+station, take photographs and have prints in the hands of the commanding
+officer inside of an hour, if all goes well.
+
+Carefully the photographs were examined by men expert in such matters.
+Eagerly they looked to discover some signs of the emplacement of the big
+gun. But one after another of the experts shook his head.
+
+"Nothing there," was the verdict.
+
+"Then we've got to try again," decided Major de Trouville. "We must
+find that gun and destroy it!"
+
+"Well, we're ready," announced Tom, and the others of the picked
+squadron nodded in assent.
+
+And then began an organized campaign to locate the monster cannon. It
+continued to fire on Paris at intervals. Then three days went by without
+any shells falling, and the rumor became current that the gun had burst.
+If this had happened, there was another, or more, to take its place, for
+again the bombarding of the city began.
+
+Meanwhile the air scouts did their best to find the place of the firing.
+Hundreds of photographs were taken, and brave scouts risked death more
+than once in flying low over suspected territory. But all to no purpose.
+Several were killed, but others took their places. Jack was hit and so
+badly wounded that he was two weeks in the hospital. But when he came
+out he was again ready to join Tom in the search.
+
+No word came as to the whereabouts of Bessie and her mother, nor did Tom
+hear anything of his father. The lack of information was getting on the
+nerves of both boys, but they dared not stop to think about that, for
+the army needed their best efforts as scouts of the air, and they gave
+such service gladly and freely.
+
+Every possible device was tried to find the location of the German gun,
+and numerous battles above the clouds resulted at different times during
+the scout work.
+
+On the whole the advantage in these conflicts lay with the armies of the
+Allies, the Germans being punished severely. Once a German plane was
+brought down within the French lines, and its pilot made a prisoner.
+
+It was hoped that some information might be gotten out of the German
+airman that would lead to the discovery of the big gun, but, naturally,
+he did not reveal the secret; and no more pressure was brought to bear
+on him in this matter than was legitimate. The hiding place of the gun
+remained a secret.
+
+Its possible size and the nature of its shooting was discussed every day
+by Tom, Jack and their comrades. In order to make a cannon shoot a
+distance of about eighty miles it was known that it was necessary to get
+the maximum elevation of forty-five degrees. It was also calculated that
+the shell must describe a trajectory the highest point in the curve of
+which must be thirty-five miles or more above the earth. In other words
+the German cannon had to shoot in a curve thirty-five miles upward to
+have the missile fly to Paris. Of course at that height there was very
+little air resistance, which probably accounted for the ability of the
+missile to go so far. That, and the sub-calibre shell, made the
+seemingly impossible come within the range of possibility.
+
+"What are you going to do, Tom?" asked Jack one evening, after an
+unsuccessful day's flight. For Tom was going toward his hangar.
+
+"Going up."
+
+"What for?" Jack went on.
+
+"Oh, no reason in particular. I just feel like flying. We didn't do much
+to-day. Had to come back on account of mist, and we didn't see enough to
+pay for the petrol used. Want to come along?"
+
+"Oh, I might, yes."
+
+Tom and Jack went up, as did several more. But the two remained up
+longer than did the others, and Jack was somewhat surprised to see his
+chum suddenly head for the German lines, but at an angle that would take
+him over them well to the south of where the observation work had been
+carried on.
+
+"I wonder what he's up to," mused Jack; "Guess I'd better follow and
+see."
+
+There was not much chance of an aerial battle at that hour, for dusk was
+coming on. There had been no bombing squadron sent out, which would
+have accounted for Tom going to meet them, and Jack wondered greatly at
+his chum's action.
+
+Still there was no way of asking questions just then, and Jack followed
+his friend. They sailed over the German lines at a good height, and Jack
+could keep Tom in view by noting the lights on his plane.
+
+These were also seen by the Germans below, and the anti-aircraft guns
+began their concert, but without noticeable effect. None of the Hun
+airmen seemed disposed to accept a challenge to fight, so Tom and Jack
+had the upper air to themselves.
+
+Below them the boys could see flashes of fire as the various guns were
+discharged; and at one point in the lines there was quite an artillery
+duel, the French batteries sending over a shower of high explosive
+shells in answer to the challenge from the Boches.
+
+It was not until Jack had followed his chum back to Camp Lincoln, and
+they had made a landing, that a conversation ensued which was destined
+to have momentous effect.
+
+"Jack, did you notice the peculiar colored lights away to the north of
+where we were flying?" asked Tom, as they divested themselves of their
+fur garments.
+
+"You mean the orange colored flare, that turned to green and then to
+purple?" asked Jack.
+
+"That's it. I thought you'd see it. I wonder what it means?"
+
+"Oh, perhaps some signal for a barrage or an attack. Or they may have
+been signaling another battery to try to pot us."
+
+"No, I hardly think so. They didn't look like signal fires. I must ask
+Major de Trouville about that."
+
+"What?" inquired the major himself, who was passing and who heard what
+Tom said.
+
+"Why, we noticed some peculiar lights as we were flying over the German
+lines in the dark. There was an orange flare, followed by a green light
+that changed to purple," answered Tom.
+
+"There was!" cried the major, seemingly much excited. "You don't mean
+it! That's just what we've been hoping to see! Come, you must tell
+Laigney about this."
+
+
+
+
+CHAPTER XX
+
+THE BIG GUN
+
+
+For a moment Tom and Jack did not quite know what to make of the
+excitement of Major de Trouville. And excited he certainly was beyond a
+doubt.
+
+"You must come and tell this to Lieutenant Laigney at once," he said.
+"It may mean something important. Are you sure of the sequence of the
+colors?" he asked. "That makes all the difference."
+
+"There was first an orange tint," said Tom, "which was followed by green
+and purple, the last gradually dying out."
+
+"Orange, green and purple," murmured the major. "Can it be that for
+which we are seeking?"
+
+He hurried along with the boys, seemingly forgetting, in his haste and
+excitement, that he was their ranking officer. But, as has been noted,
+the aviators are more like friends and equals than officers and men.
+There is discipline, of course, but there is none of the rigidity seen
+in other branches of the army. In fact the very nature of the work
+makes for comradeship.
+
+Tom and Jack knew, slightly, the officer to whom Major de Trouville
+referred. Lieutenant Laigney was an ordnance expert, and the inventor of
+a certain explosive just beginning to be used in the French shells. It
+was simple, but very powerful.
+
+"You must tell him what you observed--the strange colored lights, my
+boys," said the major. "By the way, I hope you carefully noted the time
+of the colored flares."
+
+Tom and Jack had. That was part of their training, to keep a note of
+extraordinary happenings and the time. Often seemingly slight matters
+have an important bearing on the future.
+
+They found Lieutenant Laigney in his quarters, making what seemed to be
+some intricate calculations. He saluted the major and nodded to the
+boys, whom he had met before.
+
+"Lieutenant," began Major de Trouville, "these young gentlemen have
+something to tell you. I want you to think it over in the light of what
+you told me about the action of that new explosive you said the Germans
+might possibly be using."
+
+"Very good, Major. I shall be delighted to be of any service in my
+power," was the answer.
+
+Then Tom and Jack described what they had seen, giving the location of
+the colored lights as nearly as they could, and the exact time they had
+noted them.
+
+"How long would it take a shell to reach Paris, fired at a distance of
+eighty miles from the city?" asked the major.
+
+The lieutenant made some calculations, and announced the result of his
+findings.
+
+"Then," went on the commanding officer, "if a shell was fired from the
+big gun, say at the moment when these two scouts observed the
+tri-colored fire, it should have reached Paris at seven-fifty-three
+o'clock."
+
+"As nearly as can be calculated, not knowing the exact speed of the
+projectile, yes," answered the lieutenant.
+
+Major de Trouville picked up the telephone and asked to be connected
+with the wireless station.
+
+"Have you had any reports of the bombarding of Paris this evening?" he
+asked. "Yes? What time did the first, or any particular shell, arrive?
+Ah, yes, thank you. That is all at present."
+
+He turned to the others, after having listened to the reply and put the
+instrument away.
+
+"One of the shells exploded in a Paris street at seven-fifty-two o'clock
+this evening," he said.
+
+"It beat your calculations by one minute, Lieutenant Laigney."
+
+"Ah! Then this means--" and the younger officer seemed as excited as the
+major had been when Tom and Jack told him what they had seen.
+
+"It means," finished the commanding officer, "that, in all likelihood,
+these young men have discovered the location of the big German cannon."
+
+"Discovered it!" cried Jack. "Why we didn't see anything!"
+
+"Nothing but those queer lights," added Tom.
+
+Major de Trouville smiled at them, and Lieutenant Laigney nodded his
+head in assent.
+
+"Those queer lights, as you call them," said the ordnance expert, "were
+the flashes of a new explosive. What the Germans call it I do not know.
+For want of a better name we call it Barlite, from the name of Professor
+Barcello, one of our experimenters, who discovered it. But a spy stole
+the secret and gave it to Germany. They must have managed to perfect it,
+though we have not used it as yet, owing to the difficulty in
+constructing a gun strong enough to withstand its terrific power."
+
+"And do you mean they're using this explosive in the big German gun?"
+asked Jack, "And that we really saw it being fired?" cried Tom.
+
+"That is my belief," said the lieutenant. "This explosive burns, when
+fired from a gun, first with an orange flame, changing to green and then
+to purple, as the various gases are given off."
+
+"Those are the very colors we saw!" exclaimed Jack.
+
+"Yes," went on Major de Trouville. "And when I heard you mention them,
+and when I recalled that Lieutenant Laigney had spoken of a certain
+explosive that gave off a tri-colored light, I suspected you had hit on
+the German secret."
+
+"And do you believe we actually saw the giant cannon being fired at
+Paris?" asked Tom.
+
+"Without a doubt. The time of the arrival of one of the shells coincides
+almost to the minute with the time that would elapse after the missile
+was sent on its way, and this was when you saw the queer flashes. You
+have discovered the area where the big gun is placed. All that is needed
+now are some exact observations to give us the exact spot."
+
+"And then we can destroy it!" cried the lieutenant. "Then the menace to
+beloved Paris will have passed!"
+
+"And thanks to our brave American friends!" cried the major, shaking
+hands with Tom and Jack. "You will win promotion for this!" he murmured.
+
+"But the big gun isn't found yet," said Jack.
+
+"Why, if you are right, sir," Tom said to the major, "the shells must
+pass right over our camp."
+
+"They probably do. But at so far above--several miles up so as to reach
+the height of thirty-five--that we never know it. We neither see them
+nor hear them. Boys, I believe you have located the big gun! All that
+now remains is to destroy it!"
+
+
+
+
+CHAPTER XXI
+
+DEVASTATING FIRE
+
+
+Modestly enough Tom and Jack took the new honors that came to them. As a
+matter of fact they were in no wise sure that they had discovered the
+location of the German giant cannon. It was all well enough to come in
+and report seeing some strange-colored flares of fire. But Tom and Jack
+felt that they wanted to see a thing with their own eyes before surely
+believing.
+
+Of course, though, the French experts knew about what they were talking,
+and the major and the lieutenant seemed very sure of their ground.
+
+"I only hope we have had the good luck to have spotted the beasts'
+machine," said Tom.
+
+"You will have the honor of proving it to yourselves in the morning,"
+Major de Trouville told them. "You shall accompany the first scouting
+party that goes out. We will send out two photographing machines, and
+enough of a squadron to meet anything the Huns can put forth. Paris
+shall be delivered from the Boche pests!"
+
+"We'll do our best," said Tom, and Jack nodded in agreement.
+
+It did not take long for the news to spread about Camp Lincoln that the
+two young United States aviators had, very probably, discovered by
+accident the big German gun.
+
+And in telling what they had seen Tom and Jack remarked that the
+peculiar tri-colored fire had been in the midst of other flashes of
+flame, and, doubtless, smoke, but that could not be seen on account of
+the darkness.
+
+"The other flashes were probably guns fired to camouflage the flash from
+the giant cannon, or possibly cannons," observed Major de Trouville.
+"But we shall see what to-morrow brings forth."
+
+The hours of the night seemed long, but there was much to do to get
+ready for the next day's operations. More aviators were sent for, and
+the men of the air spent many hours tuning up their motors and seeing to
+their guns, while the big machines, which it was hoped could take
+pictures of the giant cannon's position, were gone over carefully.
+
+In addition some powerful French guns were brought up--some of the
+longest range guns available, and it was hoped that the big aeroplanes
+might signal by wireless the exact location of the super-gun, so that a
+devastating fire could be poured on it, as well as bombs be dropped
+from some machines especially fitted for that work.
+
+Camp Lincoln, where the picked squadron was situated, was in the
+neighborhood of Soissons, France, in a sector held by the French troops.
+The lines of German and French trenches, with No Man's Land in between,
+was about ten miles to the east of this point. This section had changed
+hands twice, once being occupied by the Germans, and then abandoned by
+them when they made the great withdrawal.
+
+Now, perhaps ten miles back of the German trenches, the great gun was
+hidden, making its total distance from Paris about eighty miles, but its
+distance from Camp Lincoln something less than twenty miles.
+
+Modern guns easily shoot that distance, but the commander of the forces
+in this section was going to shorten that. Soissons was the nearest
+large city to the camp. As a matter of fact the air squadron was some
+distance east of that place, and nearer the battleline. So that it was
+comparatively easy, once the location of the big gun was known, to bring
+up heavy artillery behind the French lines to batter away at its
+emplacement.
+
+After a night of arduous labor, during which there was anxiety lest the
+Germans find out what was going on, morning broke, and to the relief of
+all it was bright.
+
+There was an early breakfast, and then the aviators' helpers wheeled the
+machines from the hangars. Several big photographing craft were in
+readiness, and ten bombing planes were in reserve.
+
+Major de Trouville inspected his brave men. They were as eager as dogs
+on the leash to be off and at the throat of the Huns. A wireless message
+from Paris had come in soon after breakfast, stating that nearly a score
+had been killed in the capital the previous night by fire from the
+"Bertha."
+
+"And it's up to us to avenge them!" exclaimed Jack.
+
+"That is what we'll do if we have any luck!" added Tom grimly.
+
+There was a last consultation of the officers, instructions were gone
+over, and everything possible done to insure success. The moment a big
+gun was sighted, the signal was to be given and the French long-range
+cannon would open fire, while the bombing machines would also do their
+part.
+
+"All ready! Go!" called the major, and there was a rattle and a roar
+that drowned his last word. The men of the air were off.
+
+Led by Tom and Jack, the others followed. Up and up they arose, the
+smaller planes flying high as a protection to the more cumbersome
+machines of the bi-motored type. And soon the squadron, the largest that
+had yet ascended from Camp Lincoln, was hovering over the German lines.
+
+The Huns seemed to realize that something more than an ordinary attack
+from the air was impending, for soon after the anti-aircraft guns began
+firing a swarm of German aviators took the air, and there was no
+shirking battle this time. The Huns so evidently felt the desperate need
+of driving away their attackers, that this, more than what the major and
+lieutenant had said, convinced Tom and Jack that they were at last on
+the track of the big gun.
+
+Of course the two boys could not communicate with one another, but they
+said afterward that their thoughts were the same.
+
+The battle of the air opened with a rush and a roar. The Germans, though
+outnumbered by their opponents, did not hesitate, but came on fiercely.
+They attacked first the big photographing planes, for they realized that
+these were the real "eyes" of the squadron. The impressions they
+received, and the views they carried back, might mean the failure of the
+German plans.
+
+But the French were ready for this, and the swift little Nieuports,
+dashing here and there, swooping and rising, attacked the other planes
+vigorously.
+
+It was give and take, hammer and tongs, fire and be fired on, smash and
+be smashed. It was not as one-sided a battle as it would seem it might
+have been owing to the superiority of numbers in favor of the French--at
+least at first. Several of the Allies' planes were sent down, either out
+of control, or in flames. But the Huns paid dearly for their quarry.
+
+Jack and Tom ran serious risks, for the Germans, realizing that the two
+leading planes had some special mission, attacked them fiercely. Tom
+managed to shake off and disable his antagonist. But Jack's man shot
+with such good aim that he pierced his gasolene tank, and had it not
+been that Jack was able to thrust into the hole one of some wooden plugs
+he had brought along for the purpose, he might have had to come down
+within the German lines. But the wood swelled, filled the hole, and then
+the petrol came out so slowly that there was comparatively little
+danger.
+
+And having, with some of their companions, fought their way through the
+German air patrol, and having escaped with minor damage to their guns,
+Jack and Tom looked down at the place where they had seen the queer
+lights.
+
+And then, high up and at a vantage point, while below them hovered their
+photographing planes, the two young aviators beheld a curious sight.
+
+In German-occupied territory, but on French soil, they saw near a
+railroad junction, where they were fairly well hidden in a camouflaged
+position, not one, but three monster Hun cannons. The guns looked more
+like gigantic cranes than like the accepted form of a great rifled piece
+of armament. The guns were so mounted that they could be run out on a
+small track at the moment of firing, and then propelled back again, like
+some of the disappearing cannon at Sandy Hook and other United States
+forts. Only the German guns advanced and retreated horizontally, while
+the usual method is vertically.
+
+"We've discovered 'em! There they are!" cried Tom, but of course he
+could not hear his own voice above the roar of his motor. But he knew
+that he and Jack were over the very spot where the night before they had
+seen the colored flares from the great guns.
+
+And they had, indeed, by a most lucky chance, located the big German
+guns, for there were three of them. They were placed almost midway
+between the railroad station of Crepyen-Lannois and the two forts known
+as "Joy Hills," forts which had fallen into German hands. There were
+two railroad spur lines from the station, and on these the heavy guns
+were moved to position to fire, and then run back again. Other spur
+lines were under course of construction, Jack and Tom, as well as the
+other airmen, could observe, indicating that other guns were to be
+mounted, perhaps to take the place of some that might be destroyed.
+
+As a matter of fact, as was learned later, there were but two guns in
+service at this time, one of the three having burst.[1]
+
+[Footnote 1: While of course this story is fiction, the description
+given above of the great guns and their method of firing and concealment
+is strictly in accord with the facts, and made from a sight of aeroplane
+photographs taken by the French, and from an official report, published
+April 26, 1918, by Deputy Charles Leboucq of the Department of the
+Seine.]
+
+Even as the French squadron came hovering over the place where the
+German monster guns were placed, the advance of Tom, Jack and their
+comrades being disputed by the Huns, one of the super-guns was run out
+to fire on its specially constructed platform.
+
+That this should be done in the very faces of the French was probably
+accounted for by the fact that the Germans were taken by surprise. It
+took some little time to arrange for firing one of the big cannons, and
+it was probably too late, after the French airmen were hovering above
+it, to get word to the crew not to discharge it.
+
+As it happened, Tom and Jack, with Boughton, who had kept pace with
+them, witnessed the firing of the big gun. As it was discharged, ten
+other heavy guns, but, of course, of much less range, were fired off,
+being discharged as one to cover the report of the giant mortar. And at
+the same time dense clouds of smoke were sent up from surrounding hills,
+in an endeavor to screen the big gun from aeroplane observation. But it
+was too late.
+
+In another moment, and even as the echoes of the reports of the ten
+cannons and the big gun were rumbling, the bombing machine of the French
+came up and began to drop explosives on the spot. At the same time word
+of the location of the great cannon was wirelessed back to the camp, and
+there began a devastating fire on the guns that had been, and were even
+then, bombarding Paris.
+
+
+
+
+CHAPTER XXII
+
+OVER THE RHINE
+
+
+It was a battle of the air and on the ground at the same time. From
+above the French, American and British airmen were dropping tons of
+explosives on the emplacements of the big guns and on the railway spurs
+that brought them to the firing points. It might seem an easy matter for
+an airship flying over a place to drop an explosive bomb on it and
+destroy it. But, on the contrary, it is very difficult.
+
+The bombing plane must be constantly on the move, and it takes a pretty
+good eye to calculate the distance from a great height sufficiently well
+to make a direct hit.
+
+But a certain percentage of the bombs find their mark, and they did in
+this case. Tom and Jack, as well as the other scouts, looking down from
+their planes, saw fountains of brown earth being tossed into the air as
+the French bombs exploded. At the same time the photographers in the
+other planes were making pictures of the guns and their location.
+
+They were hindered in this not only by the shooting of the Germans from
+below, who were working their anti-aircraft guns to their capacity, but
+by screens of smoke clouds, which were emitted by a special apparatus to
+hide the big guns. At the same time other cannons were being fired to
+disguise the sound from the immense long-range weapon, but this was of
+little effect, now that the location had been discovered.
+
+Meanwhile a score or more of the Hun planes appeared in the air. They
+had taken flight as soon as their pilots saw the squadron of enemy
+machines approaching, and were eager, this time, to give battle.
+
+"Our work's being cut out for us," murmured Tom, as he steered his
+machine to engage a German who seemed eager for the fray. Tom sent a
+spray of bullets at his enemy, and was fired at in turn. He knew his
+craft had been hit several times, but he did not think it was seriously
+damaged.
+
+Jack, too, as he could tell by a quick glance, was also engaged with a
+German, but Tom had no time then to bestow on mere observation. His
+antagonist was a desperate Hun, bent on the utter destruction of Tom's
+machine. They came to closer quarters.
+
+Down below the fighting was growing more furious. It was in the form of
+an artillery duel. For now the French observation machines were
+wirelessing back the range, and French shells were falling very near the
+big guns.
+
+The heavy guns, in modern warfare, are placed miles away from the
+objects they wish to hit, and the only way to know where the targets are
+is by aeroplane observation. When the guns are ready to fire one of the
+artillery control planes goes up over the enemy's territory. Of course
+it is the object of the enemy to drive it away if possible.
+
+But, hovering in the air, the observer in the double-motored machine
+notes the effect of the first shot from his side's cannon. If it goes
+beyond the mark he so signals by wireless. If it falls short he sends
+another signal. Thus the range is corrected, and finally he sees that
+the big shells are landing just where they are needed to destroy a
+battery, or whatever is the object aimed at. The observation complete,
+the machine goes back over its own lines--if the Germans let it.
+
+This sort of work was going on below them while Tom, Jack and the others
+in the Nieuports were engaging in mortal combat with the Hun fliers.
+Some of the heavy French shells fell beyond the emplacements of the big
+guns, and others were short. The observers quickly made corrections by
+wireless for the gunners. Tom Raymond, after a desperate swoop at his
+antagonist, sent him down in flames, and then, seeking another to
+engage, at the same time wondering how Jack had fared, the young aviator
+looked down and saw one of the largest of the French shells fall
+directly at the side of the foremost of the three German giant cannons.
+
+There was a terrific explosion. Of course, Tom could not hear it because
+of his height and the noise his motor was making, but he could see what
+happened. A great breach was made in the long barrel of the German gun,
+and its emplacement was wrecked, while the men who had been swarming
+about the place like ants seemed to melt into the earth. They were
+blotted out.
+
+"One gone!" exclaimed Tom grimly. And then he noted that the other two
+guns had been withdrawn beneath the camouflage. They were no longer in
+sight, and hitting them was a question of chance.
+
+Still the French batteries kept up their fire, hoping to make another
+hit, but it would be a matter of mere luck now, for the guns were out of
+observation.
+
+The airmen observers, however, still had a general idea of where the
+super-weapons were, and the French gunners continued to send over a rain
+of shells, while the bombing machines, save one that had been destroyed
+by the German fire, kept dropping high explosives in the neighborhood.
+
+"The place will be badly chewed up, at any rate," mused Tom.
+
+He glanced in the direction where he had last seen Jack, and to his
+horror saw his chum's machine start downward in a spinning nose dive.
+
+"I wonder if they've got him, or if he's doing that to fool 'em,"
+thought Tom. As he was temporarily free from attack at that instant he
+started toward his friend. Hovering over him, and spraying bullets at
+Jack, was a German machine, and Tom realized that this fighter might
+have injured, or even killed, Jack.
+
+"Well, I'll settle your hash, anyhow!" grimly muttered the young birdman
+to himself. He sailed straight for the Hun, who had not yet seen him,
+and then Tom opened fire. It was too late for the German to turn to
+engage his second antagonist, and Tom saw the look of hopelessness on
+his face as the bullets crashed into his machine, sending it down a
+wreck.
+
+"So much for poor old Jack!" cried Tom.
+
+They were well over the German lines now, and the fight was going
+against the French. That is, they were being outnumbered by the Hun
+planes, which were numerous in the air. But the French had accomplished
+their desperate mission. One of the German guns was out of commission,
+and perhaps others, while the location had been made "considerably
+unhealthy," as Boughton expressed it afterward.
+
+It was time for the French to retire, and those of their machines that
+were able prepared to do this. But Tom was going to see first what
+happened to Jack before he returned to his lines.
+
+"He may be spinning down, intending to get out of a bad scrape that way,
+and then straighten for a flight toward home," mused Tom. "Or he may
+be--"
+
+But he did not finish the sentence.
+
+There was but one way for Tom to be near Jack when the latter landed--if
+such was to be his fate--and to give him help, provided he was alive.
+And that was for Tom himself to go down in a spinning nose dive, which
+is the speediest method by which a plane can descend. But there is great
+danger that the terrific speed may tear the wings from the machine.
+
+"I'm going to risk it, though," decided Tom.
+
+Down and down he spun, and as he looked; he became aware, to his joy,
+that Jack had his machine under some control.
+
+"He isn't dead yet, by any means," thought Tom. "But he may be hurt. I
+wonder if he can make a good landing? If he does it will be inside the
+German lines, though, and then--"
+
+But Tom never faltered. He must rescue his chum, or attempt to, at all
+hazards.
+
+Down went both machines, Jack's in the lead, and then, to his joy, Tom
+saw his friend bring the machine on a level keel again and prepare to
+make a landing. This was in a rather lonely spot, but already, in the
+distance, as Tom could note from his elevated position, Germans were
+hurrying toward the place, ready to capture the French machine.
+
+"If he's alive I'll save him!" declared Tom. "My machine will carry
+double in a pinch, but he'll have to ride on the engine hood."
+
+Tom was going to take a desperate chance, but one that has been
+duplicated and equalled more than once in the present war. He was going
+to descend as near Jack's wrecked machine as he could, pick up his chum,
+and trust to luck to getting off again before the Germans could arrive.
+
+That Jack was once more master of his craft became evident to his
+friend. For the Nieuport was slowing down and Jack was making ready for
+as good a landing as possible under the circumstances. It was plain,
+however, that his machine was damaged in some way, or he would have gone
+on flying toward his own lines.
+
+Tom saw his chum drop to the ground, and then saw him quickly climb out
+of his seat, loosing the strap that held him in. By this time other
+German planes were swooping toward the place, and a squad of cavalry was
+also galloping toward it.
+
+"I'll beat you, though!" cried Tom fiercely.
+
+He throttled down his engine, intending to give it just enough gas to
+keep it going, for he would have no one to start it for him if the motor
+stalled. He calculated that he could taxi the craft across the ground
+slowly enough for Jack to jump on and then he could get away, saving
+both of them.
+
+Jack understood the plan at once. He waved his hand to Tom to show that
+he would be ready, and Tom felt a joy in his heart as he realized that
+his chum was uninjured.
+
+Down to the ground went Tom, and he guided his machine toward Jack,
+standing beside his own damaged craft, waiting. Suddenly there was a
+sharp report, and Tom saw Jack's machine burst into flames.
+
+"He fired into the gasolene tank!" thought Tom. "That's the boy! He
+isn't going to let the Huns get his machine and the maps and
+instruments. Good!"
+
+Jack leaped back from the blaze that suddenly enveloped his aeroplane
+and then ran toward Tom's machine. As he leaped upon the engine hood,
+which he could do with little more risk than boarding a swiftly moving
+trolley car, there was a burst of rifle fire from the cavalry, some of
+which had reached the scene.
+
+Jack gave a gasping cry, and fell limp. He almost slipped from the motor
+hood, but with one hand Tom quickly fastened his companion's life belt
+to the support and then, knowing Jack could not fall off, opened his
+engine wide.
+
+Across the ground the double-loaded craft careened, while the cavalry
+opened fire.
+
+"If they hit me now, it's all up with both of us!" thought Tom
+desperately.
+
+But though the bullets splattered all around him, and some hit the
+machine, neither he nor Jack was struck again, nor was any vital part of
+the machinery damaged. Poor Jack, though, seemed lifeless, and Tom
+feared he had arrived the fraction of a minute too late.
+
+Then up rose Tom's plane, up and up, the powerful engine doing its best,
+though the machine was carrying double weight. But the Nieuports are
+mechanical wonders, and once the craft was free of the earth it began
+climbing. Fortunately there were no swift German machines near enough to
+give effective chase, though some of the heavier bi-motored craft opened
+fire, as did the cavalry from below, as well as some of the
+anti-aircraft guns.
+
+But Tom, keeping on full speed, soon climbed up out of danger, and then
+swung around for a flight toward his own lines. He could see, ahead of
+him, the fleet of French planes, going back after the raid on the big
+guns. Tom's plane was the rearmost one.
+
+Then he knew that he was safe! But he feared for Jack!
+
+One after another, such as were left of the raiding party landed. Their
+comrades crowded around them, congratulating them with bubbling words of
+joy. Yet there was sorrow for those that did not return.
+
+"Is he dead?" asked Tom, as orderlies quickly unstrapped Jack, and
+prepared to carry him to the hospital. "Is he dead?"
+
+"Alive, but badly wounded," said a surgeon, who made a hasty
+examination.
+
+And then all seemed to become dark to Tom Raymond.
+
+"Well, Jack, old man, how do you feel?"
+
+"Oh, pretty good! How's yourself?"
+
+"Better, now that they've let me in to see you."
+
+"You got the big guns, I understand."
+
+"You mean _you_ did, too. It was as much your doings as mine. Yes, we
+sprayed 'em good and proper. They won't fire on Paris again right away,
+but I suppose they'll not give up the trick, once they have learned it.
+But we have their number all right. Now you want to hurry up and get
+well."
+
+Jack was in the hospital recovering from several bullet wounds. They had
+not been as dangerous as at first feared, but they were bad enough. Tom
+had come to see him and give some of the details of the great raid,
+which Jack had been unable to hear because of weakness. Now he was
+convalescing.
+
+"What's the idea of hurry?" asked Jack. "Are we going after more big
+cannon?"
+
+"No, this is a different stunt now. We're going over the Rhine."
+
+"Over the Rhine?" and Jack sat up in bed.
+
+"Monsieur--I must beg--please do not excite him!" exclaimed a pretty
+nurse, hurrying up. "The doctor said he must keep quiet."
+
+"But I want to hear about this," insisted Jack. "Over the Rhine! Say,
+that'll be great! Carrying the war into the enemy's country for fair!"
+
+"I'll tell you a little later," promised Tom, moving away in obedience
+to an entreaty from the nurse.
+
+
+
+
+CHAPTER XXIII
+
+OFF FOR GERMANY
+
+
+Whether it was Tom's news or Jack's natural health was not made clear,
+but something certainly caused Jack Parmly to recover strength much more
+rapidly then the surgeons had believed possible, so that he was able to
+leave the hospital soon after Tom's visit.
+
+"And now I want you to explain what you meant by saying we were to go
+over the Rhine," Jack insisted to his chum. "I've been wondering and
+thinking about it ever since you mentioned it, but none of them would
+tell me a thing."
+
+"No, I reckon not," chuckled Tom.
+
+"Why, you old sphinx?"
+
+"Because they didn't know. It's a secret."
+
+"Can you tell me?"
+
+"Sure! Because you're going to be in it if you are strong enough."
+
+"Strong enough? Of course I'll be! Why, I'm feeling better every minute!
+Now you go ahead and relieve my anxiety. But first tell me--have you had
+any news of your father?"
+
+Tom shook his head.
+
+"Not a word," he answered. "I'm beginning to feel that he has been
+captured by the Germans."
+
+"That's bad," murmured Jack. "And now, have you heard anything about--"
+
+"Bessie and her mother?" finished Tom, breaking in on his chum's
+question with a laugh. "Yes, I'm glad I can give you good news there.
+They are all right, and I have a letter from Bessie for you. She wants
+you to come and see her."
+
+"You have a letter? Why didn't you give it to me before? You fish!"
+
+"It just came. And so did news about their safety."
+
+"Then the spy didn't get 'em after all."
+
+"Oh, yes, he got 'em all right! But he bungled the job, or rather,
+Bessie bungled it for him. They were rescued, and the spy was locked up.
+We're to go to Paris to see them. They'll tell us all about it then."
+
+"But what has that to do with our going over the Rhine?"
+
+"Nothing. We're to go to Paris for a rest, and to get in shape for a big
+effort against the Germans. I'll tell you about it."
+
+"Forge ahead, then."
+
+Tom got up to look at the doors and windows of the French cottage back
+of the lines, where Jack had been moved to complete his recovery. Tom
+and Jack, after the sensational raid, had been given leave of absence.
+
+"I just want to make sure no one hears what I say, for it's a dead
+secret yet," Tom went on. "But this is the plan. The French have several
+of the biggest and newest Italian planes--planes that can carry half a
+dozen men and lots of ammunition. Our aerodrome is going to be shifted
+to the Alsace-Lorraine front, and from there, where the distance to
+German territory is shorter than from here, we are to go over the Rhine
+and bombard some of their ammunition and arms factories, and also
+railroad centers, if we can reach 'em."
+
+"Good!" cried Jack. "I'm with you from the fall of the hat!"
+
+"First you've got to build up a little," stated Tom. "There is no great
+rush about this Rhine-crossing expedition. A lot of plans have to be
+perfected, and we've got to try out the Italian plane. And, before that,
+we are to go to Paris."
+
+"Who says so?"
+
+"Major de Trouville. He's greatly pleased with the result of the raid on
+the big German guns, and says we're entitled to a vacation. Also he
+knows I want to make some more inquiries about my father. But I fear
+they will be useless," and Tom sighed.
+
+"And are we to go to see Mrs. Gleason?" asked Jack.
+
+"Yes. And Bessie, too. They'll tell us all that happened."
+
+A few days later, having received the necessary papers, Tom and Jack
+were once more on their way to the capital. And this time they did not,
+with others, have to suffer the danger and annoyance of the long-range
+bombardment. It was over for a time, but there was no guarantee that the
+Germans would not renew it as soon as they could repair the damage done
+to their giant cannons.
+
+The boys found Bessie and her mother in lodgings in a quiet part of
+Paris, and were met with warm greetings. Then the Gleasons told their
+story.
+
+They had been inveigled out of their lodgings by the false note from the
+boys, and had immediately been taken in charge by the spy, who, it was
+proved, was an agent of the infamous Potzfeldt. But Bessie, after
+several days' captivity in an obscure part of the great city, managed to
+drop a letter out of the window, asking for help.
+
+The police were communicated with, and not only rescued Mrs. Gleason and
+her daughter, but caught the spy as well, and secured with him papers
+which enabled a number of Germany's ruthless secret service agents to be
+arrested.
+
+It was because of the necessity for keeping this part of the work quiet
+that no word of the rescue of Bessie and her mother was sent to the boys
+until after the big gun raid.
+
+There was much to be talked about when the friends met once more, and
+Mrs. Gleason said she and Bessie were going back to the United States as
+soon as they could, to get beyond the power of Potzfeldt.
+
+As Tom had feared, there was no news of his father, but he did not yet
+give up all hope.
+
+"If he's a prisoner there's a chance to rescue him," he said.
+
+The time spent in Paris seemed all too short, and it came to an end
+sooner than the boys wished. Jack was almost himself again, though he
+limped slightly from one of the German bullets in his leg. There was
+every hope, however, that this would pass away in time.
+
+Good-byes were said to Bessie and her mother, and once more the two Air
+Service boys reported to their aerodrome. There they found not one, but
+two, of the big Italian machines, which are capable of long flight,
+carrying loads that even the most ponderous bombing plane would be
+unable to rise with.
+
+Preparations for the bold dash into the enemy's country went on
+steadily and swiftly. Tom and Jack were trained in the management of the
+big birds of the air, and though it was essentially different from what
+they had been used to in the Nieuports and the Caudrons, they soon
+mastered the knack of it, and became among the most expert.
+
+"I believe I made no mistake when I picked them to be part of the
+raiding force," said Major de Trouville.
+
+"Indeed you did not," agreed Lieutenant Laigney. "Their work in
+discovering the big guns, and their help in silencing them, showed what
+sort of boys they are."
+
+And finally the day came when those who were to take part in the raid
+across the Rhine were to proceed to a point within the French lines from
+which the start was to be made.
+
+Other Italian planes would await them there, and there they would
+receive final instructions.
+
+They bade farewell to their comrades in Camp Lincoln, and were given
+final hand-shakes, while more than one, struggling to repress his
+emotion wished them "_bonne chance_!"
+
+This raid against one of the largest and most important of the German
+factory and railroad sections had long been contemplated and details
+elaborately worked out for it. The start was to be made from the nearest
+point in French-occupied territory, and it was calculated that the big
+Italian machines could start early in the evening, cross the Rhine,
+reach their objective by midnight, drop the tons of bombs and be back
+within the French lines by morning.
+
+Such, at least, was the hope. Whether it would be realized was a matter
+of anxious conjecture.
+
+At last all was in readiness. The final examinations of the machines and
+their motors had been made and the supplies and bombs were in place.
+
+"Attention!" called the commander. "Are you ready?"
+
+"Ready!" came from Tom, who was in command of one machine.
+
+"Ready!" answered Haught, who was in charge of the second.
+
+"Then go, and may good fortune go with you!"
+
+There was a roar of the motors, and the big, ponderous machines started
+for Germany.
+
+Would they ever reach it?
+
+
+
+
+CHAPTER XXIV
+
+PRISONERS
+
+
+Under the evening stars, the two big Italian machines slowly, and, it
+must be said, somewhat ponderously, as compared with a speedy Nieuport,
+winged their way toward the German river, behind which it was hoped,
+some day, to drive the savage Huns.
+
+"What do you think?" asked Jack of his chum, for in these latest
+machines, by reason of the motors being farther from the passengers, and
+by means of tubes, some talk could be carried on.
+
+"I don't know just what to think," was the answer. "So much has happened
+of late, that it's almost beyond my thinking capacity."
+
+"That's right. And yet I can guess one thing you have in mind, Tom, old
+scout."
+
+"What is it?"
+
+"Your father! You're hoping you can rescue him."
+
+"That's right, I am. And as soon as this drive is over--if we come back
+from it with any measure of success, and I can get a long leave of
+absence--I'm going to make a thorough search for him."
+
+"And I'll be with you; don't forget that!"
+
+There was not time for too much talk of a personal nature, as Tom and
+Jack had to give their attention to the great plane. The motors were
+working to perfection, and with luck they should, within a few hours, be
+over the great German works, which they hoped to blow up.
+
+Tom was in charge of the plane, but he had Jack and others to help him,
+and there was a certain freedom of movement permitted, not possible in
+even the big photographing or bombing planes.
+
+Down below little could be seen, for they were now over the French and
+German trenches, and neither side was showing lights for fear of
+attracting the fire of the other.
+
+But Tom and Jack had been coached in the course they were to take and,
+in addition, they had a pilot who, a few weeks before, had made a
+partially successful raid in the region beyond the Rhine, barely
+escaping with his life.
+
+And so they flew on under the silent stars, that looked like the small
+navigating lights on other aeroplanes. But, as far as the raiders knew,
+they were the only ones aloft in that particular region just then. They
+had risen to a good height to avoid possible danger from the German
+anti-aircraft guns. There was not much danger from the German planes,
+as, of late, the Huns had shown no very strong liking for night work,
+except in necessary defense.
+
+Off to the left Tom and Jack could see the other big Italian plane, in
+charge of Haught. It carried only small navigating lights, carefully
+screened so as to be invisible from below.
+
+"I suppose you understand the orders," said Tom, speaking to Jack.
+
+"Well, we went over them; but it wouldn't do any harm to refresh my
+memory. You're to be in general charge of the navigation of the plane,
+and I'm to see to dropping the bombs--is that it?"
+
+"That's it. You'll have to use your best judgment when it comes to your
+share. I'll get you over the German works and railroad centers, as
+nearly as I can in the dark, and then it will be up to you."
+
+"I hope I don't fail," said Jack, speaking through the tube.
+
+"You won't. Don't get nervous. Any kind of a hit will throw a scare into
+the Huns, and make them feel that they aren't the only ones who can make
+air raids. But in this case we're not bombing a defenseless town, and
+killing women and children. This is a fortified place we're going over,
+and it's well defended."
+
+"Some difference," agreed Jack.
+
+"And if we can get some direct hits," went on Tom, "and blow to
+smithereens some of their munition or armament factories, we'll be so
+much nearer to winning the war."
+
+And that, in brief, was the object of the flight over the Rhine.
+
+Once more the boys fell silent.
+
+On and on swept the planes. Whether the Germans beneath were aware of
+the danger that menaced them, it is impossible to say. But they made no
+attempt to fire on the Italian craft. Probably because of the darkness,
+and owing to the great height at which they flew, the Huns were in
+ignorance of what was taking place.
+
+On and on in the night and beneath the silent stars they flew. Now Tom
+and the pilot began watching for some landmark--some cluster of lights
+which would tell them their objective was within sight. But for another
+hour nothing was done save to guide the big craft steadily onward.
+
+Once, as Jack looked down, he saw what seemed to be a city, and he
+thought this might be the place where the great factories were situated.
+
+"No, it's an important town," Tom said, in answer to his chum's
+inquiries, "but it is only a town--not a fortress, as the Huns call
+London. That isn't fair game for us."
+
+But half an hour later the pilot spoke sharply, and gave an order. He
+pointed downward and ahead and there a faint glow, and one that spread
+over a considerable area, could be made out.
+
+"That is where we are to drop the bombs," said Tom to Jack.
+
+The other machine, which had flown somewhat behind the one in which were
+the two chums, now swerved over at greater speed. Her pilot, too, had
+picked up the objective.
+
+And now began the most dangerous part of the mission. For it would not
+do to drop the bombs from too great a height. There was too much risk of
+missing the mark. The planes must descend, and then they would be within
+range of the defensive guns.
+
+But it had to be done, and the order was given. As Jack and Tom went
+lower, in company with the other plane, they observed that they were
+over a great extent of factory buildings, where German war work was
+going on.
+
+And now the noise of their motors was heard. Searchlights flashed out
+below them, and stray beams picked them up. Then the anti-aircraft guns
+began to bark.
+
+"We're in for a hot time!" cried Jack.
+
+"You said it!" echoed Tom, as he steered the great plane to get into an
+advantageous position.
+
+Through a glare of light, and amid a hail of shots, the great airships
+rushed down to hover over the German factories. They would not let go
+their bombs until in a position to do the most damage, and this took a
+little time.
+
+"How about it, Tom?" asked Jack, for he was anxious to begin dropping
+the bombs.
+
+"Just another minute. We'll go down a little lower, and so do all the
+more damage."
+
+And down the airship went. She was hit several times, for shrapnel was
+bursting all around, but no material damage was done, though one of the
+observers was wounded.
+
+"Now!" suddenly signaled Tom.
+
+"There they go!" shouted Jack, and he released bomb after bomb from the
+retaining devices.
+
+Down they dropped, to explode on striking, and the loud detonations
+could be heard even above the roar of the motors. Tom noted that the
+other machine was also doing great destruction, and he saw that their
+object had been accomplished.
+
+Several fires broke out below them in different parts of the factory
+property, and soon the Germans had to give so much attention to saving
+what they could, that their fire against the hostile airships noticeably
+slackened.
+
+"Any more bombs left, Jack?" asked Tom.
+
+"A few," answered his chum.
+
+"Let 'em have it now. We're right over a big building that seems to be
+untouched."
+
+Down went the bombs, and such an explosion resulted that it could mean
+but one thing. They had set off a munition factory. This, as the boys
+afterward learned, was the case.
+
+So great was the blast that the great plane skidded to one side, and a
+moment later there came a cry of alarm from some of the crew.
+
+"What's the matter?" shouted Tom.
+
+"Out of control," was the answer. "One of the motors has stopped, and
+we've got to go down."
+
+"Can't we go up?"
+
+"No!" was the despairing answer. "We've got to land within the German
+lines."
+
+And down the great Italian plane went, while her sister ship of the air
+sailed safely off, for it would have been foolhardy for her to have
+tried to come to the rescue.
+
+The crew worked desperately to send their craft up again, but it was
+useless. Lower and lower she went, fortunately not being fired at, so
+great was the confusion caused by the destruction of the factories.
+
+"Take her down as far away as possible from this scene," said Tom to one
+of his men. "If we land in a lonely place we may be able to make repairs
+and get up again."
+
+"I will," was the answer.
+
+Through the light from the burning buildings, a spot in a level field
+was selected for a landing. And down the Italian plane went.
+
+A hasty examination showed little wrong with the motor, and this little
+was quickly repaired.
+
+But the hope of getting the airship to rise again was frustrated, for
+just as the raiding party was about to take its place in the machine
+again, a company of German soldiers came running over the fields,
+demanding the surrender of the intrepid men of the air. There was
+nothing else to do--no time to set the craft on fire.
+
+So it fell into the hands of the Germans! Tom, Jack and the others were
+prisoners!
+
+
+
+
+CHAPTER XXV
+
+THE ESCAPE
+
+
+"Well, this is tough luck!"
+
+"Tough is no name for it, Jack. It's the worst ever! I don't suppose
+they'll do a thing to us after what we did to the factories."
+
+"No. We certainly scotched 'em good and proper. Everything went off like
+a tea party, except our coming down. And we could have gotten up again,
+only those Germans didn't give us a chance."
+
+"You can't blame 'em for that."
+
+"No, I suppose not. But it's hard lines. I wonder why they're keeping us
+here?"
+
+Tom and Jack were talking thus while held prisoners by the Germans,
+after the airship raid over the Rhine. It was an hour after they had
+been forced to descend.
+
+So sudden had been the rush of the German infantry that no chance was
+had to destroy the great Italian plane, and it, and all the crew,
+including the two Air Service boys, had been overpowered, and disarmed.
+They were thrust into what might pass for a guardhouse, and then, a
+guard having been posted, the other soldiers hurried back to aid in
+fighting the fire which had been started in the great factories, and
+which was rapidly spreading to all the German depot.
+
+"Well, it's worth being captured to think of the damage we've inflicted
+on the Huns this night," observed Jack, as he stood with Tom in the
+midst of their fellow prisoners.
+
+"That's right. We don't need to be ashamed of our work, especially as
+we've helped put the big guns out of business. I reckon the Boches won't
+treat us any too well, when they know what we've done."
+
+"And the other plane got away, they tell me," observed one of the French
+crew.
+
+"Yes, I saw her rise and light out for home, after dropping a ton or so
+of bombs on this district," said Tom. "Well, she can go back and report
+a success."
+
+"And let the folks know we're prisoners," said Jack. "It's tough luck,
+but it had to be, I suppose! We're lucky to be alive."
+
+"You said it," agreed Tom. "We came through a fierce fire, and it's a
+wonder that we weren't all shot to pieces. As it is, the plane is as
+good as ever."
+
+"Yes, and if we could only get out to it, and start it going we could
+escape," observed one of the Frenchmen bitterly. "There she is now, on
+as good a starting field as one could wish!"
+
+From their stockade of barbed wire they could look out and see, by the
+glare of the flames, that the great plane stood practically undamaged. A
+good landing had been made, but, unfortunately, in the midst of the
+German ammunition depot section.
+
+"Whew, that was a fierce one!" exclaimed Jack, as a loud explosion
+fairly shook the place where they were held prisoners. "Some ammunition
+went up that time."
+
+Indeed the explosion did seem to be a disastrous one, for there was
+considerable shouting and the delivering of orders in German following
+the blast. Many of the soldiers who had been summoned to stand on guard
+about the barbed-wire stockade, where the captured raiders were held,
+were summoned away, leaving only a small number on duty.
+
+But as these were well armed, and as the wire stockade was a strong one,
+and as Jack, Tom and the others had nothing with which to make a fight,
+they were as safely held as though guarded by a regiment.
+
+"There goes another!" cried Jack, as a second detonation, almost as loud
+as the first, shook the ground. "Some of our bombs must have been time
+ones."
+
+"No," said Tom. "What's probably happening is that the fire is reaching
+stores of ammunition, one after the other. This whole place may go up in
+a minute."
+
+That seemed to be the fear on the part of the Germans, for more orders
+were shouted, and all but two of the soldiers guarding the captives were
+summoned away from the wire stockade.
+
+There had been a bright flare of fire after the second explosion, but
+this soon died away, and the shouts and commands of the officers
+directing the fire-fighting force could be heard.
+
+Tom and Jack were standing near the wire barrier trying to look out to
+see what was going on beyond a group of ruined factory buildings, and at
+the same time casting longing eyes at the great aeroplane which seemed
+only waiting for them, when the two boys became aware of a figure which
+appeared to be slinking along the side of the stockade. This figure
+acted as though it desired to attract no attention, for it kept as much
+as possible in the shadows.
+
+"Did you see that?" asked Jack of his churn in a low voice.
+
+"Yes. What do you make it out to be?"
+
+"He isn't a German soldier, for he isn't in uniform. Have any of our
+crowd found a way out of this place by any chance?"
+
+"I don't know. If they have--"
+
+The boy's words were broken off by a low-voiced call from the slinking
+figure. It asked:
+
+"Are you American, French or English prisoners?"
+
+"Some of each variety," answered Jack, while at the sound of that voice
+Tom Raymond felt a thrill of hope.
+
+"If you get out, is there a chance for you to get away in your
+aircraft?" the figure in the shadow questioned. "Be careful, don't let
+the guards hear."
+
+"There are only two, and they're over at the front gate," said Jack, as
+Tom drew nearer in order better to hear the tones of that voice. "They
+seem more occupied in watching the fire than in looking at us," went on
+Jack.
+
+"Good!" exclaimed the man. "Now listen. I am an American, and I was
+captured by the Germans, through spy work, some time ago, in Paris. I
+was brought here, and they have been trying to force me to disclose the
+secret of some of my inventions.
+
+"I refused, and was sentenced to be shot to-morrow. But to-night you
+fortunately raided this place. My prison was one of the places to be
+blown up, and I managed to escape, without being hurt much. I heard that
+they had captured the crew of one of the airships, and I came to see if
+I could help. They don't know yet that I'm free, and I have two hand
+grenades.
+
+"Now listen carefully. I'll throw the grenades at the front gate. By
+shattering that it may be possible for you to get out. The two sentries,
+will have to take the chances of war. If you get out can you get away in
+your airship?"
+
+"Yes, and we can take you with us--Dad!" exclaimed Tom in a tense
+whisper.
+
+"Who speaks?" hoarsely asked the man in the shadow of the stockade.
+
+"It is I--your son--Tom Raymond! Oh, thank heaven I have found you at
+last!" exclaimed Tom, and he tried to stretch his hand through the
+barbed wire, but it was too close.
+
+"Is it really you, Tom, my boy?" asked Mr. Raymond in a broken voice,
+full of wonder.
+
+"Yes! And to think I should find you here, of all places!" whispered
+Tom. "I won't stop now to ask how it happened. Can you throw those
+grenades at the gate?"
+
+"I can, and will! Tell your friends to run back to the far end of the
+stockade to avoid being hurt. I can crouch down behind some of the
+ruined walls."
+
+Tom and Jack quickly communicated the good news to their friends, that a
+rescue was about to be attempted. It was a desperate chance, but they
+were in the mood for such.
+
+The two guards alone remaining of the force that had been posted about
+the stockade were so distracted by the fires and explosions around them,
+and so fearful of their own safety, that they did not pay much attention
+to the prisoners. So when Tom and Jack passed the word, and the airship
+crew ran to the end of the stockade and crouched down to avoid injury
+when the hand grenades should be exploded, the guards paid little
+attention.
+
+Mr. Raymond, for it was indeed he, crawled to a position of vantage, and
+then threw the hand grenades. They were fitted with short-time fuses,
+and almost as soon as they fell near the stockade gate they exploded
+with a loud report. A great hole was torn in the ground, and one of the
+sentries was killed while the other was so badly injured as to be
+incapable of giving an alarm. The gate was blown to pieces.
+
+"Come on!" cried Tom to his friends, as he saw what his father had done.
+"It's now or never, before they rush in on us."
+
+They raced to the breach in the wire wall of the stockade. Mr. Raymond,
+springing up from where he had taken refuge behind a pile of refuse, was
+there to greet those he had saved, and he and Tom clasped hands silently
+in the gloom that was lighted up by the fires and the bursts of light
+from the munition explosions.
+
+"Oh, Dad! And it's really you!" murmured Tom.
+
+"Yes, my boy! _I_ never expected to see you again. Did you know I was
+here?"
+
+"I never dreamed of it! But don't let's stop to talk. We must get to the
+airship at once! But you are wounded, Dad!"
+
+"Nothing but a splinter from a bomb. It's only a cut on the head, Son,"
+and Mr. Raymond wiped away the blood that trickled down on his face.
+
+The newly freed prisoners lost no time. With a rush they made for the
+airship. If they could only get aboard and start it off all would yet be
+well. Could they do it?
+
+Momentary silence had followed the detonation of the two hand grenades
+thrown by Mr. Raymond, but now there came yells of rage from the
+Germans, disclosing that they had become aware of what was going on.
+
+"Lively, everybody!" cried Tom, as he led the way to the big plane.
+
+"Are we all here?" asked Jack.
+
+A rapid count showed that not one of the brave force had been left
+behind.
+
+"Is there room for me?" asked Mr. Raymond.
+
+"Well, I should say so!"
+
+"If there isn't I'll stay behind," cried Jack.
+
+"No you won't!" exclaimed Tom. "There'll be room all right!"
+
+The running men reached the plane just as they could see, in the light
+of the burning factories, a squad of Germans rushing to intercept them.
+In haste they scrambled aboard, and pressed the self-starter on the
+engine. There was a throbbing roar, answered by a burst of fire from the
+German rifles, for the place had been so devastated that no machine guns
+were available just then.
+
+"All aboard?" asked Tom, as he stood ready to put the motors at full
+speed and send the craft along the ground, and then up into the air.
+
+"All aboard--we're all here!" answered Jack, who had kept count. And Mr.
+Raymond was included.
+
+Then with a louder roar the motors jumped to greater speed, and the
+Italian plane started off. In another instant it rose into the air.
+
+With yells of rage the Germans even tried to hold it back with their
+hands, and, failing, they increased their fire. But though the plane was
+hit several times, and two on board shot, one later dying from his
+wounds, the whole party got off. A few minutes later they were above the
+burning factories, and had a view of the great destruction wrought on
+the German base. So completely destroyed was it that few defense guns
+were left in condition to fire at the aeroplane.
+
+"Well, we did that in great shape!" exclaimed Jack, as they were on
+their way over the Rhine again.
+
+"Couldn't have been better," conceded Tom. "And, best of all, we have
+dad with us."
+
+"How did it all happen?" asked Jack.
+
+"I don't know. We'll hear the story when we are safe in France."
+
+And safe they were as the gray morning broke. They arrived just as the
+crew of the other plane were relating, with sorrow, the fall of Tom,
+Jack and their comrades, and the rejoicing was great when it was known
+they were safe, and had not only outwitted the Huns, but had brought
+away a most important prisoner.
+
+"And now let's hear how it all happened," begged Major de Trouville,
+when the injured had been made as comfortable as possible. There were
+three of these, and one dead on the plane that returned first.
+
+The story of the attack on the German base was given in detail, and then
+Mr. Raymond took up the tale from the point where he had landed in
+Europe.
+
+He had started for Paris, just as he had written Tom, and had taken
+lodgings in the Rue Lafayette. He went out just before the starting of
+the bombardment by the big gun, and so escaped injury, but he fell into
+the hands of some German spies, who were on his trail, and who
+succeeded, after having drugged him, in getting him into Germany.
+
+The spies had succeeded in getting on the trail of a new invention Mr.
+Raymond had perfected, and which he had offered to the Allies. He had
+come to Paris on this business. The Huns demanded that he devote it to
+their interests, but he refused, and he had been held a prisoner over
+the Rhine, every sort of pressure being brought to bear on him to make
+him accede to the wishes of his captors.
+
+"But I refused," he said, "and they decided I should be shot. Whether
+this was bluff or not I don't know. But they never got a chance at me.
+In the night I heard, in my prison, the sound of explosions, and I soon
+realized what had happened. It was your bold airship raid, and one of
+the bombs burst my prison. I ran out and saw the Italian planes in the
+air.
+
+"What then happened you know better than I, but what you probably do not
+know is that you very likely owe your lives to a dispute that arose
+between the German infantry and the air squadron division," and he
+indicated Tom, Jack and the others who had been in the stockade.
+
+"How was that?" asked Jack.
+
+"The airmen claimed you as their prey, and the infantrymen said they
+were entitled to call you theirs. So, even in the midst of the fire and
+destruction, the commandant had to order you put in the stockade until
+he could decide whose prisoners you were. The infantrymen said they had
+captured you, but the airmen said their fire had brought down your
+plane."
+
+"Well, that was partly true," said Tom. "But it was an explosion from
+below that knocked us out temporarily. But we're all right now. And so
+are you, aren't you, Dad?"
+
+"Yes, but I worried a lot, not knowing what had happened to you, Tom,
+and being unable to guess what would happen to me. I was in the hands of
+clever and unscrupulous enemies. How clever they were you can judge when
+I tell you they took me right out of Paris. Perhaps the bombardment made
+it easier. But tell me--what of the big guns?"
+
+"Some of them are out of commission, thanks to your brave boy and his
+comrades," said Major de Trouville.
+
+"Good!" cried Mr. Raymond. "Some rumor to that effect sifted in to me
+there, but it seemed too good to be true. The Germans must be wild with
+rage."
+
+"I guess they are," admitted Jack.
+
+"And it would have gone hard with you if they had found you were the
+ones responsible," went on Tom's father. "As soon as I was out of my
+prison and saw the state of affairs, I managed to get the grenades, and
+I decided to rescue the airship men if I could. I never dreamed my own
+son would be among them, or that I might be brought away."
+
+And now it but remains to add that because of their exploits Tom and
+Jack received new honors at the hands of the grateful French, and,
+moreover, were promoted.
+
+Mr. Raymond, who had steadfastly refused to reveal the secret of his
+invention to the Huns, immediately turned it over to the Allies.
+
+Word of Mr. Raymond's safety and of the success of Tom and Jack was sent
+to those in Bridgeton, and that city had new reasons for being proud of
+her sons.
+
+But the war was not over, and the Germans might be expected to develop
+other forms of frightfulness besides the long-range guns, which, for the
+time being, were silenced. However, the destruction of the factories and
+ammunition stores by the raid over the Rhine was a blow that told
+heavily on the Hun.
+
+"Well, it seems there's another vacation coming to us," said Tom to Jack
+one morning, as they walked away from the breakfast table in their
+mess.
+
+"Yes? Well, I think we can use it. What do you say to a run into Paris
+to see your father? He's surely there now, and I'd like to have a talk
+with him."
+
+"With--_him?_" asked Tom, and there was a peculiar smile on his face.
+
+"Of course," said Jack.
+
+"Oh," was all Tom answered, but he laughed heartily.
+
+And so, with Tom and Jack on their way to Paris, for a brief respite
+from the war, we will take leave of them for a time. That they were
+destined to take a further part in the great struggle need not be
+doubted, for the Air Service boys were not the ones to quit until the
+world had been made a decent place in which to live.
+
+THE END
+
+
+
+
+
+End of the Project Gutenberg EBook of Air Service Boys Over The Rhine, by 
+Charles Amory Beach
+
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+      The Project Gutenberg eBook of Air Service Boys Over The Rhine, by Charles Amory Beach.
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+<pre>
+
+Project Gutenberg's Air Service Boys Over The Rhine, by Charles Amory Beach
+
+This eBook is for the use of anyone anywhere at no cost and with
+almost no restrictions whatsoever.  You may copy it, give it away or
+re-use it under the terms of the Project Gutenberg License included
+with this eBook or online at www.gutenberg.org
+
+
+Title: Air Service Boys Over The Rhine
+       Fighting Above The Clouds
+
+Author: Charles Amory Beach
+
+Illustrator: Robert Gaston Herbert
+
+Release Date: October 3, 2010 [EBook #33834]
+
+Language: English
+
+Character set encoding: ISO-8859-1
+
+*** START OF THIS PROJECT GUTENBERG EBOOK AIR SERVICE BOYS OVER THE RHINE ***
+
+
+
+
+Produced by Bruce Albrecht, Mary Meehan and the Online
+Distributed Proofreading Team at http://www.pgdp.net
+
+
+
+
+
+
+</pre>
+
+
+
+
+
+<h1>AIR SERVICE BOYS OVER THE RHINE</h1>
+
+<h3>OR, FIGHTING ABOVE THE CLOUDS</h3>
+
+<h2>BY CHARLES AMORY BEACH</h2>
+
+<h3><span class="smcap">Author of "Air Service Boys Flying for France,"<br /> "Air Service Boys Over
+the Enemy's Lines," Etc.</span></h3>
+
+
+<h3>ILLUSTRATED BY<br />
+ROBERT GASTON HERBERT</h3>
+
+<h3>THE SAALFIELD PUBLISHING CO.<br />
+AKRON, OHIO       NEW YORK</h3>
+
+<h3>MADE IN U.S.A.</h3>
+
+<h3><span class="smcap">Copyright, 1919, by<br />
+George Sully &amp; Company</span></h3>
+
+
+
+<hr style="width: 65%;" />
+
+<div class="figcenter">
+<img src="images/illus.jpg" alt=""/>
+</div>
+
+<h3>BLOWING UP THE GERMAN MUNITION FACTORY.</h3>
+
+
+
+<hr style="width: 65%;" />
+<h2>CONTENTS</h2>
+
+<!-- Autogenerated TOC. Modify or delete as required. -->
+<p>
+<a href="#CHAPTER_I">CHAPTER I <span class="smcap">Double News</span></a><br />
+<a href="#CHAPTER_II">CHAPTER II <span class="smcap">Anxious Days</span></a><br />
+<a href="#CHAPTER_III">CHAPTER III <span class="smcap">On to Paris</span></a><br />
+<a href="#CHAPTER_IV">CHAPTER IV <span class="smcap">Suspicions</span></a><br />
+<a href="#CHAPTER_V">CHAPTER V <span class="smcap">The Bombardment of Paris</span></a><br />
+<a href="#CHAPTER_VI">CHAPTER VI <span class="smcap">The Rue Lafayette Ruins</span></a><br />
+<a href="#CHAPTER_VII">CHAPTER VII <span class="smcap">Tom's Father</span></a><br />
+<a href="#CHAPTER_VIII">CHAPTER VIII <span class="smcap">Where Is Mr. Raymond?</span></a><br />
+<a href="#CHAPTER_IX">CHAPTER IX <span class="smcap">Various Theories</span></a><br />
+<a href="#CHAPTER_X">CHAPTER X <span class="smcap">The "Dud"</span></a><br />
+<a href="#CHAPTER_XI">CHAPTER XI <span class="smcap">A Monster Cannon</span></a><br />
+<a href="#CHAPTER_XII">CHAPTER XII <span class="smcap">For Perilous Service</span></a><br />
+<a href="#CHAPTER_XIII">CHAPTER XIII <span class="smcap">The Spy</span></a><br />
+<a href="#CHAPTER_XIV">CHAPTER XIV <span class="smcap">With Comrades Again</span></a><br />
+<a href="#CHAPTER_XV">CHAPTER XV <span class="smcap">The Picked Squadron</span></a><br />
+<a href="#CHAPTER_XVI">CHAPTER XVI <span class="smcap">Missing</span></a><br />
+<a href="#CHAPTER_XVII">CHAPTER XVII <span class="smcap">Seeking the Gun</span></a><br />
+<a href="#CHAPTER_XVIII">CHAPTER XVIII <span class="smcap">A Cloud Battle</span></a><br />
+<a href="#CHAPTER_XIX">CHAPTER XIX <span class="smcap">Queer Lights</span></a><br />
+<a href="#CHAPTER_XX">CHAPTER XX <span class="smcap">The Big Gun</span></a><br />
+<a href="#CHAPTER_XXI">CHAPTER XXI <span class="smcap">Devastating Fire</span></a><br />
+<a href="#CHAPTER_XXII">CHAPTER XXII <span class="smcap">Over The Rhine</span></a><br />
+<a href="#CHAPTER_XXIII">CHAPTER XXIII <span class="smcap">Off For Germany</span></a><br />
+<a href="#CHAPTER_XXIV">CHAPTER XXIV <span class="smcap">Prisoners</span></a><br />
+<a href="#CHAPTER_XXV">CHAPTER XXV <span class="smcap">The Escape</span></a><br />
+</p>
+<!-- End Autogenerated TOC. -->
+
+<hr style="width: 65%;" />
+<h2>AIR SERVICE BOYS OVER THE RHINE</h2>
+
+
+
+<hr style="width: 65%;" />
+<h2><a name="CHAPTER_I" id="CHAPTER_I"></a>CHAPTER I</h2>
+
+<h3>DOUBLE NEWS</h3>
+
+
+<p>"Here they come back, Tom!"</p>
+
+<p>"Yes, I see them coming. Can you count them yet? Don't tell me any of
+our boys are missing!" and the speaker, one of two young men, wearing
+the uniform of the Lafayette Escadrille, who were standing near the
+hangars of the aviation field "somewhere in France," gazed earnestly up
+toward the blue sky that was dotted with fleecy, white clouds.</p>
+
+<p>There were other dots also, dots which meant much to the trained eyes of
+Tom Raymond and Jack Parmly, for the dots increased in size, like
+oncoming birds. But they were not birds. Or rather, they were human
+birds.</p>
+
+<p>The specks in the sky were Caudrons. A small aerial fleet was returning
+from a night raid over the German ammunition dumps and troop centers,
+and the anxiety of the watching young men was as to whether or not all
+the airmen, among whom were numbered some of Uncle Sam's boys, had
+returned in safety. Too many times they did not&mdash;that is not all&mdash;for
+the Hun anti-aircraft guns found their marks with deadly precision at
+times.</p>
+
+<p>The Caudrons appeared larger as they neared the landing field, and Tom
+and Jack, raising their binoculars, scanned the ranks&mdash;for all the world
+like a flock of wild geese&mdash;to see if they could determine who of their
+friends, if any, were missing.</p>
+
+<p>"How do you make it, Tom?" asked Jack, after an anxious pause.</p>
+
+<p>"I'm not sure, but I can count only eight."</p>
+
+<p>"That's what I make it. And ten of 'em went out last night, didn't
+they?"</p>
+
+<p>"So I heard. And if only eight come back it means that at least four of
+our airmen have either been killed or captured."</p>
+
+<p>"One fate is almost as bad as the other, where you have to be captured
+by the Boches," murmured Jack. "They're just what their name
+indicates&mdash;beasts!"</p>
+
+<p>"You said something!" came heartily from Tom. "And yet, to the credit of
+airmen in general, let it be said that the German aviators treat their
+fellow, prisoners better than the Hun infantrymen do."</p>
+
+<p>"So I've heard. Well, here's hoping neither of us, nor any more of our
+friends, falls over the German lines. But look, Tom!" and Jack pointed
+excitedly. "Are my eyes seeing things, or is that another Caudron
+looming up there, the last in the line? Take a look and tell me. I don't
+want to hope too much, yet maybe we have lost only one, and not two."</p>
+
+<p>Tom changed the focus of his powerful glasses slightly and peered in the
+direction indicated by his chum. Then he remarked, with the binoculars
+still at his eyes:</p>
+
+<p>"Yes, that's another of our machines! But she's coming in slowly. Must
+have been hit a couple of times."</p>
+
+<p>"She's lucky, then, to get back at all. But let's go over and hear what
+the news is. I hope they blew up a lot of the Huns last night."</p>
+
+<p>"Same here!"</p>
+
+<p>The aircraft were near enough now for the throbbing of their big motors
+to be heard, and Tom and Jack, each an officer now because of gallant
+work, hurried across the landing field.</p>
+
+<p>It was early morning, and they had come, after a night's rest, to report
+for duty with others of the brave Americans who, during the neutrality
+of this country in the great conflict, went to France as individuals,
+some to serve as ambulance drivers, others to become aviators.</p>
+
+<p>The Caudron is the name given to one type of heavy French aeroplane
+carrying two or more persons and tons of explosive bombs.</p>
+
+<p>An air raid on the German lines by a fleet of these machines had been
+planned. It had been timed for an early hour of the night, but a mist
+coming up just as the squadron of heavy machines, each with two men and
+a ton or more of explosives, was ready to set out, the hour had been
+changed. So it was not until after midnight that the start had been
+made.</p>
+
+<p>And now the boys were coming back&mdash;that is all who were able to return.
+One machine was missing. At least, that was the assumption of Tom and
+Jack, for they could count but nine where there should have been ten.
+And of the nine one was coming back so slowly as to indicate trouble.</p>
+
+<p>One by one the machines, which ordinarily came back before daybreak,
+landed, and the pilot and the observer of each climbed clumsily down
+from their cramped seats. They were stiff with cold, in spite of the
+fur-lined garments they wore&mdash;garments that turned them, for the moment,
+into animated Teddy bears, or the likeness of Eskimos.</p>
+
+<p>Their faces were worn and haggard, for the strain of an airship bombing
+raid is terrific. But they were quiet and self-possessed as they walked
+stiffly across the field to make a report.</p>
+
+<p>"Any luck?" asked Tom, of one he knew; a Frenchman noted for his skill
+and daring.</p>
+
+<p>"The best, <i>mon ami</i>," he replied with a smile&mdash;a weary smile. "We gave
+Fritz a dose of bitter medicine last night."</p>
+
+<p>"And he gave us a little in return," sadly added his companion. "Quarre
+and Blas&mdash;" he shrugged his shoulders, and Tom and Jack knew what it
+meant.</p>
+
+<p>They were the men in the missing machine, the Caudron that had not come
+back.</p>
+
+<p>"Did you see what happened?" asked Jack.</p>
+
+<p>Picard, to whom Tom had first spoken, answered briefly.</p>
+
+<p>"They caught them full in the glare of a searchlight and let them have
+it. We saw them fall. There didn't seem to be any hope."</p>
+
+<p>"But the battery that did the firing&mdash;it is no more," added De Porry,
+the companion of Picard. "The bombs that Quarre and Blas carried went
+down like lead, right on top of the Hun guns. They are no more, those
+guns and those who served."</p>
+
+<p>"It was a retributive vengeance," murmured Picard.</p>
+
+<p>Then they passed on, and others, landing, also went to make their
+reports.</p>
+
+<p>Some of them had reached their objectives, and had dropped the bombs on
+the German positions in spite of the withering fire poured upward at
+them. Others had failed. There is always a certain percentage of
+failures in a night bombing raid. And some were unable to say with
+certainty what damage they had caused.</p>
+
+<p>The last slowly flying machine came to a landing finally, and there was
+a rush on the part of the other aviators to see what had happened. When
+Tom and Jack saw a limp form being lifted out, and heard murmurs of
+admiration for the pilot who had brought his machine back with a
+crippled engine, they realized what had happened.</p>
+
+<p>The two brave men had fulfilled their mission; they had released their
+bombs over an important German factory, and had the terrible
+satisfaction of seeing it go up in flames. But on their return they had
+been caught in a cross fire, and the observer, who was making his first
+trip of this kind, had been instantly killed.</p>
+
+<p>The engine had been damaged, and the pilot slightly wounded, but he had
+stuck to his controls and had brought the machine back.</p>
+
+<p>There was a little cheer for him, and a silent prayer for his brave
+companion, and then the night men, having made their reports, and having
+divested themselves of their fur garments, went to rest.</p>
+
+<p>"Well, what's on the programme for to-day, Tom?" asked Jack, as they
+turned back toward the hangars where they had their headquarters with
+others of their companions in the Lafayette Escadrille and with some of
+the French birdmen.</p>
+
+<p>"I don't know what they have on for us. We'll have to wait until the
+orders come in. I was wondering if we would have time to go and see if
+there's any mail for us."</p>
+
+<p>"I think so. Let's go ask the captain."</p>
+
+<p>They had, of course, reported officially when they came on duty, and now
+they went again to their commanding officer, to ask if they might go a
+short distance to the rear, where an improvised post-office had been set
+up for the flying men.</p>
+
+<p>"Certainly, messieurs," replied the French captain, when Tom proffered
+the request for himself and his chum. "Go, by all means." He spoke in
+French, a good mastery of which had been acquired by our heroes since
+their advent into the great war. "Your orders have not yet arrived, but
+hold yourselves in readiness. Fritz is doubtless smarting under the dose
+we gave him last night, and he may retaliate. There is a rumor that we
+may go after some of his sausages, and I may need you for that."</p>
+
+<p>"Does he mean our rations have gone short, and that we'll have to go
+collecting bolognas?" innocently asked a young American, who had lately
+joined.</p>
+
+<p>"No," laughed Tom. "We call the German observation balloons 'sausages.'
+And sometimes, when they send up too many of them, to get observations
+and spoil our plans for an offensive, we raid them. It's difficult work,
+for we have to take them unawares or they'll haul them down. We
+generally go in a double squadron for this work. The heavy Caudrons
+screen the movements of the little Nieuports, and these latter, each
+with a single man in it, fire phosphorus bullets at the gas bags of the
+German sausages.</p>
+
+<p>"These phosphorus bullets get red hot from the friction of the air, and
+set the gas envelope aglow. That starts the hydrogen gas to going
+and&mdash;good-night to Mr. Fritz unless he can drop in his parachute. A raid
+on the sausages is full of excitement, but it means a lot of
+preparation, for if there has any rain or dew fallen in the night the
+gas bags will be so damp that they can't be set on fire, and the raid is
+off."</p>
+
+<p>"Say, you know a lot about this business, don't you?" asked the young
+fellow who had put the question.</p>
+
+<p>"Nobody knows a <i>lot</i> about it," replied Jack. "Just as soon as he does
+he gets killed, or something happens to him. We're just learning&mdash;that's
+all."</p>
+
+<p>"Well, I wish I knew as much," observed the other enviously.</p>
+
+<p>Tom and Jack walked on toward the post-office, being in rather a hurry
+to see if there was any mail for them, and to get back to their stations
+in case their services were needed.</p>
+
+<p>As they went along they were greeted by friends, of whom they had many,
+for they had made names for themselves, young as they were. And, as a
+matter of fact, nearly all the aviators are young. It takes young nerves
+for the work.</p>
+
+<p>"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."</p>
+
+<p>"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."</p>
+
+<p>"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&mdash;great news!"</p>
+
+<p>Jack looked at his chum. Tom's face was flushed. The news seemed to be
+pleasurable.</p>
+
+<p>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.</p>
+
+<p>The man was waving a slip of paper over his head, and he was calling out
+something in French.</p>
+
+<p>"What's he saying?" asked Jack.</p>
+
+<p>"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."</p>
+
+<p>"More news," murmured Jack. "And you have some, too?"</p>
+
+<p>"I should say so! Things surely are happening this morning! Come on!"
+and Tom set off on a run.</p>
+
+
+
+<hr style="width: 65%;" />
+<h2><a name="CHAPTER_II" id="CHAPTER_II"></a>CHAPTER II</h2>
+
+<h3>ANXIOUS DAYS</h3>
+
+
+<p>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.</p>
+
+<p>"I wonder what it can be, Tom," murmured Jack, as the two fairly ran
+over the field.</p>
+
+<p>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.</p>
+
+<p>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&mdash;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.</p>
+
+<p>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.</p>
+
+<p>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.</p>
+
+<p>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 <i>Lusitania</i>, 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.</p>
+
+<p>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.</p>
+
+<p>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.</p>
+
+<p>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.</p>
+
+<p>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.</p>
+
+<p>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.</p>
+
+<p>"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?"</p>
+
+<p>"No, but we're going to," was the answer. "Oh, boy! It's great! We're in
+it now sure! Hurray!"</p>
+
+<p>"In it? What do you mean?" asked Jack.</p>
+
+<p>"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."</p>
+
+<p>"You mean&mdash;" cried Tom.</p>
+
+<p>"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?"</p>
+
+<p>"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.</p>
+
+<p>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.</p>
+
+<p>"Say, this is the best news ever!" said Jack to Tom, when quiet, in a
+measure, had been restored. "It's immense!"</p>
+
+<p>"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."</p>
+
+<p>"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."</p>
+
+<p>"Yes, I have. And now I have a chance to finish reading dad's letter."</p>
+
+<p>"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&mdash;your news and that about Uncle Sam's success in raising
+funds and troops."</p>
+
+<p>"Oh, I guess you can stand it," said Tom with a smile. "It's this. Dad
+is coming over!"</p>
+
+<p>"He is? To fight?"</p>
+
+<p>"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."</p>
+
+<p>"That's right!" exclaimed Jack, with such energy that Tom asked:</p>
+
+<p>"What's the matter? Haven't you heard from Bessie lately?"</p>
+
+<p>"Oh&mdash;that!" murmured Jack, but Tom noticed that his friend blushed under
+his coat of tan. "Go on," Jack said, a moment later, "tell me about your
+father. Is the French government going to give him a big order for his
+stabilizer, now that we got that paper away from that sneak of a
+Tuessig?"</p>
+
+<p>"Well, I guess dad's trip here has something to do with his aeroplane
+device, but he hints in his letter about something else. He said he
+didn't want to write too much for fear a spy might get hold of the
+information. But you know my father is an expert on ordnance matters and
+big guns, as well as in other lines of fighting."</p>
+
+<p>"That's so, Tom. He certainly is a wonder when it comes to inventing
+things. But what do you suppose his new mission is?"</p>
+
+<p>"I can't quite guess. But it is for the service of the Allies."</p>
+
+<p>"And you say he's on his way to Paris now?"</p>
+
+<p>"He ought to be there by this time," Tom answered. "I'm going to see if
+I can't get permission to send a message through, and have an answer
+from dad. Maybe he might get out here to see us."</p>
+
+<p>"Or we could go in and meet him."</p>
+
+<p>"Not for a week. You know we just came back from leave, and we won't be
+over our tour of duty for seven days more. But I can't wait that long
+without some word. I'm going to see what I can find out."</p>
+
+<p>Tom and Jack, like all the other American fliers, were in high favor
+with the French officers. In fact every aviator of the Allied nations,
+no matter how humble his rank, is treated by his superiors almost as an
+equal. There is not that line of demarcation noticed in other branches
+of the service. To be an aviator places one, especially in England and
+France, in a special class. All regard him as a hero who is taking
+terrible risks for the safety of the other fighters.</p>
+
+<p>So Tom readily received permission to send a message to the hotel in
+Paris mentioned by his father as the place where Mr. Raymond would stay.
+And then Tom had nothing to do but wait for an answer.</p>
+
+<p>Nothing to do? No, there was plenty. Both Tom and Jack had to hold
+themselves in readiness for instant service. They might be sent out on a
+bombing expedition at night in the big heavy machines, slow of flight
+but comparatively safe from attack by other aircraft.</p>
+
+<p>They might have the coveted honor of being selected to go out in the
+swift, single Nieuports to engage in combat with some Hun flier. To
+become an "ace"&mdash;that is a birdman who, flying alone, has disposed of
+five enemies&mdash;is the highest desire of an aviator.</p>
+
+<p>Tom and Jack, eager and ambitious, were hoping for this.</p>
+
+<p>Again, in the course of the day's work, they might be selected to go up
+in the big bi-motored Caudrons for reconnoissance work. This is
+dangerous and hard. The machines carry a wireless apparatus, over which
+word is sent back to headquarters concerning what may be observed of the
+enemy's defenses, or a possible offensive.</p>
+
+<p>Often the machines go beyond the range of their necessarily limited
+wireless, and have to send back messages by carrier pigeons which are
+carried on the craft.</p>
+
+<p>By far the most dangerous work, however, is that of "<i>relage</i>" or fire
+control. This means that two men go up in a big machine that carries a
+large equipment. Their craft is heavy and unwieldy, and has such a
+spread of wing surface that it is not easily turned, and if attacked by
+a German Fokker has little chance of escape. A machine gun is carried
+for defense.</p>
+
+<p>It is a function of those in the machine to send word back to the
+battery officers of the effect of the shots they are firing, that the
+elevation and range may be corrected. And those who go out on "<i>relage</i>"
+work are in danger not only from the fire of the enemy's batteries, but
+often, also, from their own.</p>
+
+<p>Tom and Jack had their share of danger and glory during the week they
+were on duty following the receipt of the two pieces of news. They went
+up together and alone, and once, coming back from a successful trip over
+the enemy's lines, Tom's machine was struck by several missiles. His
+cheek was cut by one, and his metal stability control was severed so
+that his craft started to plunge.</p>
+
+<p>Tom thought it was his end, but he grasped the broken parts of the
+control rod in one hand, and steered with the other, bringing his
+machine down behind his own lines, amid the cheers of his comrades.</p>
+
+<p>"And I'm glad to be back, not only for my sake, but for the sake of the
+machine. She's a beauty, and I'd have hated like anything to set fire to
+her," remarked Tom, after his wound had been dressed.</p>
+
+<p>He referred to the universal practice of all aviators of setting fire to
+their craft if they are brought down within the enemy lines, and are not
+so badly injured as to prevent them from opening the gasoline tank and
+setting a match to it. This is done to prevent the machine, and often
+the valuable papers or photographs carried, from falling into the hands
+of the enemy.</p>
+
+<p>The end of the week came, the last of seven anxious days, and it was
+time for Tom and Jack to be relieved for a rest period. And the days had
+been anxious because Tom had not heard from his father.</p>
+
+<p>"I hope the vessel he was coming on wasn't torpedoed," said Tom to his
+chum. "He's had more than time to get here and send me some word. None
+has come. Jack, I'm worried!" And Tom certainly looked it.</p>
+
+
+
+<hr style="width: 65%;" />
+<h2><a name="CHAPTER_III" id="CHAPTER_III"></a>CHAPTER III</h2>
+
+<h3>ON TO PARIS</h3>
+
+
+<p>Those were the days&mdash;and they had been preceded by many such&mdash;when
+travel across the Atlantic was attended with great risk and uncertainty.
+No one knew when a lurking German submarine might loose a torpedo at a
+ship carrying men, women and children. Many brave and innocent people
+had found watery graves, and perhaps suffered first a ruthless fire from
+the German machine guns, which were even turned on lifeboats! So it was
+no wonder that Tom Raymond was worried about his father.</p>
+
+<p>"It's queer we can't get any word from the authorities in Paris,"
+remarked Jack, as he and his chum were speculating one day on what might
+have happened.</p>
+
+<p>"Yes, and that helps to bother me," Tom admitted. "It isn't as if they
+weren't trying, for the officers here have done all they can. They've
+gotten off my messages, but they say there is no reply to them."</p>
+
+<p>"Then it must mean that your father, if he is in Paris, hasn't received
+them."</p>
+
+<p>"Either that, Jack; or else he doesn't dare reply."</p>
+
+<p>"Why wouldn't he dare to, Tom?"</p>
+
+<p>"Well, I don't know that I can give a good reason. It might be that he
+is on such a secret mission that he doesn't want even to hint about it.
+And yet I can't understand why he doesn't send me at least a message
+that he has arrived safely."</p>
+
+<p>As Tom said this he looked at his chum. The same thought was in the mind
+of each one:</p>
+
+<p>Had Mr. Raymond arrived safely?</p>
+
+<p>That was what stirred Tom's heart. He knew the danger he and Jack had
+run, coming across to do their part in flying for France, and he well
+realized that the Germans might have been more successful in attacking
+the vessel on which his father had sailed, than they had the one which
+had carried Tom and Jack.</p>
+
+<p>"Well, what are we going to do?" asked Jack of his chum. "You know we
+arranged, when we should get our leave, to go back to that pretty little
+French village, which seemed so peaceful after all the noise of battle
+and the roar of the aeroplane engines."</p>
+
+<p>"Yes, I know we planned that," said Tom, reflectively. "But, somehow, I
+feel that I ought to stay here."</p>
+
+<p>"And not take our relief?"</p>
+
+<p>"Oh, no. We'll take that," decided Tom. "We must, in justice to
+ourselves, and those we work with. You know they tell us an airman must
+always be at his best, with muscles and nerves all working together. And
+a certain amount of rest and change are necessary, after a week or so of
+steady flying. So we'll take our rest in order to be in all the better
+shape to trim the Fritzies. But I was thinking of staying right here."</p>
+
+<p>"And not go back into the country?" asked Jack.</p>
+
+<p>Tom shook his head.</p>
+
+<p>"I'd like to stay right here until I get word from my father," he said.
+"He may send a message at any time, and he knows I am stationed here. Of
+course I could send him word that we're having a little vacation, and
+give him our new address.</p>
+
+<p>"But the mails are so mixed up, and the telegraph and telephone systems
+are so rushed, that he might not get it. So I think the best thing will
+be to stay right here where I'll be on hand to get it the moment word
+comes. But don't let me keep you, Jack. You can go, if you want to."</p>
+
+<p>"Say, what do you think I am?" cried his chum. "Where you stick, I
+stick! We'll both wait here for word from your father. I have a sort of
+feeling that he is all right."</p>
+
+<p>"Well, to tell you the truth, I suppose he is. But, at the same time,
+I'm worried. I can't explain it, but I have a sort of sense that he is
+in danger."</p>
+
+<p>"Not if he is in Paris, Tom. The German's haven't gotten within striking
+distance of that city yet, in spite of their boasts&mdash;the boasts of the
+Kaiser and of the Crown Prince."</p>
+
+<p>"No, if dad were in Paris I'd feel that he was comparatively safe. But
+first I want to know that he is. And yet, even if he has put up at that
+house in the Rue Lafayette, where he said in his letter he'd stay, there
+may be some danger."</p>
+
+<p>"Danger in Paris? What do you mean, Tom?"</p>
+
+<p>"Well, Paris has been bombed from the air, you know."</p>
+
+<p>"True, Tom. But, say! we've almost come to disregard such mild things as
+that from the Huns, haven't we?"</p>
+
+<p>"Well, we'll just stay right on here," decided Tom. "I don't mean to say
+that we'll stay around our hangar all the while, but we'll keep in
+touch, throughout the day, with the communication headquarters. Dad may
+send a message at any time, and I want to get it as soon as it arrives."</p>
+
+<p>Jack could understand his chum's feelings, and so the Air Service boys,
+who, some time previous, had sought and received permission to go back
+several kilometers into the country for a rest, announced that they
+would stay on at the aerodrome.</p>
+
+<p>Nor did they lack excitement. The place where they were stationed was a
+busy one. For every twenty pilots and observers there are detailed about
+one hundred men as helpers. There are cooks, photographers, mechanics of
+various sorts, telephone, telegraph and wireless operators, orderlies
+and servants.</p>
+
+<p>Of these Tom and Jack had their share, for it is the business of an
+airman to fly and fight, and he does nothing except in that line. He is
+catered to and helped in every possible way when not in the air. He has
+some one to wait on him, to look after his machine, and to attend to his
+hurts, if he is unlucky enough to get any. Of course each flier goes
+over, personally, his own craft, but he has oilers and mechanics to do
+all the detail work.</p>
+
+<p>"Well, there they go!" exclaimed Tom to Jack one morning, the second of
+their "vacation," as they observed a number of "aces" about to go up
+and search above the clouds for some Hun to attack.</p>
+
+<p>"Yes, and I wish I was with them!" said Jack.</p>
+
+<p>"Waiting isn't much fun," agreed his chum. "I'm sure I can't understand
+why dad doesn't send some word. If this keeps up much longer&mdash;Say, Jack,
+look at Parla!" he suddenly cried. "What's the matter with him?"</p>
+
+<p>Jack looked. The men, in their machines, had started off to get momentum
+for a rise into the air. But there had been a rain and the ground was
+soft, which kept down the speed. All the pilots seemed to get off in
+fairly good shape except one, Parla by name, who had only recently
+secured the coveted designation of "ace."</p>
+
+<p>And then occurred one of those tragedies of flying. Whether he was
+nervous at taking a flight in such distinguished company, or whether
+something went wrong with Parla's machine never would be known.</p>
+
+<p>He was the last in the line, and as it was rather misty he might have
+been anxious not to lose sight of his companions. He did not take a long
+enough run, and when he reached the end of the field he was not high
+enough to clear the line of hangars that were in front of him.</p>
+
+<p>Some one shouted at him, not stopping to realize that the noise of the
+motor drowned everything else in the ears of the pilot.</p>
+
+<p>The luckless man tried to make a sharp turn, to get out of danger. One
+of his wing tips caught on the canvas tent, or hangar, and in another
+instant there was a crash and a mass of wreckage. From this, a little
+later, poor Parla was carried.</p>
+
+<p>But the others did not stay, for though the shadow of death hovered over
+the Escadrille, the business of war went on.</p>
+
+<p>After three days Tom and Jack could not stand it any longer. They begged
+for permission to go up into the air. It was granted, though officially
+they were still on leave. Ascending together in a Caudron, on a
+photographing assignment, they were attacked by two swift German
+Fokkers.</p>
+
+<p>Tom worked the gun, and to such good effect that he smashed one machine,
+sending it down with a crash, and drove the second off. So other laurels
+were added to those the boys already had.</p>
+
+<p>"If this keeps on we'll be soon wearing the chevrons of sergeants," said
+Jack, as they landed.</p>
+
+<p>"Well, I'd almost give up hope of them to hear from dad," announced
+Tom. "I'm going to see if some word hasn't come."</p>
+
+<p>But there was no message. Still the strange silence continued, and Tom
+and his chum did not know whether Mr. Raymond had reached Paris or not.
+Through his own captain, Tom appealed to the highest authority at the
+Escadrille, asking that a last imploring message be sent to the address
+in the Rue Lafayette.</p>
+
+<p>This was done, and then followed another day of waiting. At last Tom
+said:</p>
+
+<p>"Jack, I can't stand it any longer! This suspense is fierce!"</p>
+
+<p>"But what are you going to do about it?"</p>
+
+<p>"I'm going to Paris! That's what! We'll go there and find my father if
+he has arrived. If he hasn't&mdash;well, there is still some hope."</p>
+
+<p>"Go to Paris!" murmured Jack.</p>
+
+<p>"Yes. It's the only place where I can make uncertainty a certainty. Come
+on, we'll go to Paris!"</p>
+
+
+
+<hr style="width: 65%;" />
+<h2><a name="CHAPTER_IV" id="CHAPTER_IV"></a>CHAPTER IV</h2>
+
+<h3>SUSPICIONS</h3>
+
+
+<p>Tom Raymond started across the field toward headquarters. Jack followed,
+but there was a strange look on the latter's face.</p>
+
+<p>"I don't see how you're going to Paris," remarked Jack, at length. "Do
+you mean we're to go in separate machines, or together?"</p>
+
+<p>"Oh, nothing like that!" exclaimed Tom. "We won't go in machines at all.
+We'll go by train, if we can get one, or by motor."</p>
+
+<p>"But you're heading for the Escadrille Headquarters office, and&mdash;"</p>
+
+<p>"We've got to get official permission to go," explained Tom. "We can't
+rush off, whenever we like, as we used to go fishing together."</p>
+
+<p>To his captain Tom explained matters more fully than he had done before.
+In effect he related the fact of having received the letter, stating
+that Mr. Raymond had started for Paris, presumably to engage in some
+work for the French government, or at least for the Allies. Whether he
+had arrived or not, and, in the former case, to ascertain why he had
+not sent some word to his son, was the object of Tom's quest.</p>
+
+<p>"I've tried and tried, from this end, to get in touch with him,"
+explained Tom; "but something seems to happen to my messages. I know
+they leave here all right, but after that they are lost. Now I have an
+idea that there is so much going on in Paris&mdash;so much necessary war
+work&mdash;that the ordinary lines of communication are choked. But if I
+could go to the capital in person I could soon find out whether my
+father was at the address he gave."</p>
+
+<p>"And you want, do you, to go together?" asked the kindly French captain,
+smiling at Tom and Jack.</p>
+
+<p>"We'd like to go," said Tom.</p>
+
+<p>"And go you shall. I will write the necessary order. You have done well,
+and I understand you have some days of leave coming. To them I shall add
+more. But come back to me," he added, as he filled out the pass form.
+"Come back. We need you Americans now more than ever!"</p>
+
+<p>"We'll come back," promised Tom. "All I want to go to Paris for is to
+find out about my father."</p>
+
+<p>"Ah, I envy you," said the captain softly. "Both in the possession of a
+father, who must be proud to have such a son as you, and also because
+you are going to Paris. It is the most beautiful&mdash;the most
+wonderful&mdash;city in the world. And to think&mdash;to think that those
+barbarians would sack her! Ah, it is terrible!" and with a sad nodding
+of his head, following the shaking of an avenging fist toward the German
+lines, he waved Tom and Jack an adieu.</p>
+
+<p>The two Air Service boys lost little time in making their preparations
+to leave for the French capital. They had to get certain passes and
+papers, and they wished to say good-bye to some of their comrades in
+arms. For, more than any other branch of the service, is aviation
+uncertain as to life or death. Tom and Jack well knew that some, perhaps
+many, of those who wished them "<i>au revoir</i>," and "<i>bonne chance</i>,"
+would not be alive when they returned. And Tom and Jack might not return
+themselves. True, their chances were comparatively good, but the
+fortunes of war are uncertain.</p>
+
+<p>And so, after certain preliminaries, Tom and Jack, their pet machines in
+the hangars, left behind their beloved comrades and were taken by motor
+to the nearest railway station. There they secured their tickets and
+took their places to wait, with what patience they could, their arrival
+in Paris.</p>
+
+<p>The train was well filled with "<i>permissionnaires</i>," or soldiers on
+leave for a few days of happiness in the capital, and at certain
+stations, where more got on, the rush was not unlike that at a crowded
+hour in some big city.</p>
+
+<p>"I see something good," remarked Jack, as they sat looking out at the
+scenery, glad, even for a brief moment, to be beyond the horrors of war.</p>
+
+<p>"What?" asked his companion.</p>
+
+<p>"There's a dining-car on this train. We sha'n't starve."</p>
+
+<p>"Good enough, I almost forgot about eating," said Tom. "Now that you
+speak of it, I find I have an appetite."</p>
+
+<p>They ate and felt better; and it was as they were about to leave the
+dining-car to go back to their places, that Jack nudged Tom and
+whispered to him:</p>
+
+<p>"Did you hear what he said?"</p>
+
+<p>"Hear what who said?"</p>
+
+<p>"That man just back of you. Did you have a good look at him?"</p>
+
+<p>"I didn't, but I will have," said Tom, and, waiting a moment so as not
+to cause any suspicion that his act was directed by his chum, Tom turned
+and looked at the person Jack indicated. He beheld a quietly dressed
+man, who seemed to be alone and paying attention to no one, eating his
+lunch.</p>
+
+<p>"Well, what about him?" asked Tom. "I don't see anything remarkable
+about him, except that he's a slow eater. I admit I bolt my food too
+much."</p>
+
+<p>"No, it isn't that," said Jack in a low voice. "But don't you think he
+looks like a German?"</p>
+
+<p>Tom took another casual glance.</p>
+
+<p>"Well, you might find a resemblance if you tried hard," he answered.
+"But I should be more inclined to call him a Dutchman. And when I say
+Dutchman I mean a Hollander."</p>
+
+<p>"I understand," remarked Jack. "But I don't agree with you in thinking
+that he may be from Holland. Of course men of that nationality have a
+right to go and come as they choose, where they can, but I don't believe
+this chap is one."</p>
+
+<p>"Why not?"</p>
+
+<p>"Because I heard him mutter something in German."</p>
+
+<p>"Well, lots of Hollanders can speak German, I have no doubt. I can
+splutter a few words myself, but not enough to hurt me. I began to pick
+up some from the prisoners, after we had that experience with Potzfeldt,
+when we realized that even a little knowledge of the Hun's talk, much as
+we hate him, would be of service. And so you think you heard this fellow
+speak German?" asked Tom, as he pretended to tie his shoe lace, to make
+an excuse for pausing.</p>
+
+<p>"I'm sure I did," said Jack.</p>
+
+<p>"What did he say?"</p>
+
+<p>"Something about wishing he had a plate of <i>metzel suppe</i>. Of course I
+don't guarantee that pronunciation, but&mdash;"</p>
+
+<p>"Oh, it'll do," said Tom, graciously. "Well, there's nothing very
+suspicious in that, though. I might wish for some <i>wienerwurst</i>, but
+that wouldn't make me a German spy."</p>
+
+<p>"No. But take one other thing and you'll have to admit that there is
+some ground for my belief."</p>
+
+<p>"What's the other thing, old top?" asked Tom, in imitation of some
+Englishmen.</p>
+
+<p>"He was making drawings of the railroad line," asserted Jack.</p>
+
+<p>"How do you know?"</p>
+
+<p>"I saw him. He pretended to be looking at the <i>carte de jour</i>, and I
+caught a glimpse of a sheet of paper on which he was making certain
+marks. I'm sure he was sketching out something about the railroad, for
+use, maybe, in a future air raid."</p>
+
+<p>"Nonsense!" exclaimed Tom. "As a matter of fact, I don't doubt that the
+German secret agents know every foot of ground in and about Paris. They
+must have maps of this railroad the same as the French have of some of
+Germany's, only you've got to hand it to the Huns! They certainly went
+into this thing well prepared the more discredit to us, in a way. But
+are you sure of what you say, Jack?" he added, after a moment's thought.</p>
+
+<p>"Positive! I'm sure that man is a German spy, masking as a Hollander or
+possibly a Swiss. He's sighing for some of his country's good
+cooking&mdash;though that's one of the few good things about it&mdash;and he's
+making some sort of a map."</p>
+
+<p>Tom thought over the matter a moment. The man did not appear to notice
+the two chums.</p>
+
+<p>"I'll tell you what we can do," Tom said. "We'll soon be in at the Gare
+de l'Est, and we can tip off some of the officers around there. They can
+follow this fellow, if they think it's worth while."</p>
+
+<p>"Well, I think it's worth while," said Jack. "If that fellow isn't a spy
+I'm a Dutchman!"</p>
+
+<p>As Jack spoke the man looked up and full at the two lads, almost as if
+he had heard the words.</p>
+
+
+
+<hr style="width: 65%;" />
+<h2><a name="CHAPTER_V" id="CHAPTER_V"></a>CHAPTER V</h2>
+
+<h3>THE BOMBARDMENT OF PARIS</h3>
+
+
+<p>"There, Jack! what did I tell you? I win! You lose, and it's me for a
+fine dinner at your expense! You lose! Do you hear?"</p>
+
+<p>Tom Raymond, with a hearty laugh, clapped his chum on the shoulder, and
+seemed mirthfully excited over something. As for Jack Parmly he looked
+first at his chuckling comrade and then at the man he suspected of being
+a German spy. The latter, who had glanced keenly at the boys, with
+something akin to anger on his face, now was plainly puzzled.</p>
+
+<p>"Do you understand?" demanded Tom in a loud voice, which attracted the
+attention of many in the car. But a look at the two, showing them to be
+Americans and, therefore, to the French mind, capable of any
+eccentricity, seemed to make matters right. Most of the diners resumed
+their meals.</p>
+
+<p>"See what I mean, Jack?" went on Tom. "You lose! Understand?"</p>
+
+<p>"No, I don't understand," was the low-voiced and somewhat puzzled
+answer.</p>
+
+<p>"Then for the sake of your gasolene tank <i>pretend</i> that you do!"
+fiercely whispered Tom in his chum's ear. "Play up to my game! Don't you
+see that fellow's suspicious of us? He thinks we've been talking about
+him. I win, do you understand?"</p>
+
+<p>"Oh, yes," answered Jack, and then, in a louder tone, intended to allay
+suspicion on the part of the suspect, he added: "You win all right, Tom!
+I'll buy the dinner. I didn't think the train would get in so soon! It's
+one on me all right!"</p>
+
+<p>And then, laughing and talking in seeming carelessness, as though they
+had not a thought in the world but the friendly wager they had made,
+they went back to their coach.</p>
+
+<p>"That was a narrow squeak," observed Tom. "He was getting suspicious all
+right, and in another moment might have made an indignant demand of the
+guard that we cease observing him. It might have made trouble for us.
+We're not members of the secret police, remember."</p>
+
+<p>"Well," remarked Jack, "he might have made trouble for us, but I could
+do the same for him. I'd let fall a hint about the map of the railway he
+was sketching."</p>
+
+<p>"You mean all right, Jack, but I don't believe your plan would work. If
+that fellow really is a German spy, which I doubt, he'd destroy the
+map, if he made one, the moment he thought himself in danger."</p>
+
+<p>"Maybe you're right, Tom," agreed his chum, a bit dubiously. "But I
+certainly think there is something wrong about that man."</p>
+
+<p>"Maybe you think he is Carl Potzfeldt, disguised, Jack."</p>
+
+<p>"No, nothing like that. Though I wouldn't be surprised if he happened to
+be friendly with that sneaking spy. And, speaking of Potzfeldt, Tom,
+though he isn't by any means a pleasant subject, do you know we are soon
+to be in Paris where&mdash;"</p>
+
+<p>"Where Bessie and her mother are, you mean. You're right, old chap, I
+haven't forgotten that, and I'll wager one chance for promotion that you
+haven't forgotten it either."</p>
+
+<p>Jack's blush was sufficient answer to his friend.</p>
+
+<p>"I couldn't quite understand what you meant, Tom, by talking so suddenly
+and loudly about you winning and me losing," went on Jack, as they got
+their baggage ready, for the train was about to enter the Paris station.</p>
+
+<p>"That was camouflage, Jack, pure and unadulterated camouflage," answered
+Tom with a laugh. "I had to do something in a hurry to get that fellow's
+gaze off us, or he might have made a scene, and we don't want that. But
+if I had made a wager with you about the time, I'd have won, for here
+we are, right on the dot, which is unusual in these days, I believe."</p>
+
+<p>"You said something, Tom. But what are we going to do about our spy?"</p>
+
+<p>"Well, if you insist that's what he is, I think the best thing would be
+to notify some secret service official. There must be plenty of them
+around the station. Every passenger, before he leaves the station, has
+to have his papers stamped by the military authorities. Then's your
+chance to tip them off about this chap."</p>
+
+<p>"I'll do it, Tom. I'm not going to lose any chances of putting German
+enemies out of the way."</p>
+
+<p>It was about five o'clock when the train pulled into the Gare de l'Est,
+and the passengers, including many soldiers on leave, prepared for the
+joys of Paris. Tom and Jack, proceeding as did the others to the place
+designated for the official stamping of papers, found a chance to tell
+their suspicions to an officer, and to point out the man Jack suspected.</p>
+
+<p>"The matter shall be attended to," said the military official, treating
+the information with the utmost respect, and evidently considering it of
+more importance than Tom imagined would be attached to it. "We are
+greatly indebted to you, not only because you are of our beloved
+aviators, but because you also think to do this for France&mdash;to protect
+her from enemies within as well as from those who are without. France
+thanks you, gentlemen!" and the aged officer saluted the two young men
+as though he considered them his equals.</p>
+
+<p>"Well, now that's off our minds we can get down to the real business
+that brought us to Paris," suggested Tom. "And that's to find my
+father&mdash;if he's here. After that we can look up Bessie and her mother,
+if you like, Jack."</p>
+
+<p>"Of course I'll be glad to do that, Tom, and I should think that you&mdash;"</p>
+
+<p>"Oh, of a surety, yes, as a Frenchman would say. I'll be happy also, to
+see our friends again, but I know Bessie will consider&mdash;"</p>
+
+<p>"Oh, drop it, will you?" begged Jack, for he could see that his chum was
+about to start to rally him about the girl.</p>
+
+<p>"Then," went on Tom, "the first thing to do, in my opinion, is to get to
+this address in the Rue Lafayette where dad said he would make his
+headquarters, and see why he hasn't answered any of my messages. When I
+once see him, and know he's all right, I'll feel better."</p>
+
+<p>"Even capable of eating that dinner you claim to have won from me?"
+asked Jack.</p>
+
+<p>"Of course."</p>
+
+<p>The two Air Service boys had the satisfaction of seeing the "tip" they
+gave acted on, for as they left the station they observed the officer
+to whom they had reported, detailing a man in plain clothes, evidently
+one of the secret police, to follow the man they had watched in the
+dining car.</p>
+
+<p>"We can leave the rest to the military," said Tom. "And now let's get to
+where we're going."</p>
+
+<p>"Hadn't we better arrange for hotel accommodations, or to stop at a
+pension?" asked Jack. "You know Paris is crowded now, even in war times,
+and we've got to stay here all night, even if we learn that your father
+hasn't yet arrived."</p>
+
+<p>"That's so," agreed Tom. "Maybe we had better get a place to bunk
+first."</p>
+
+<p>It would not have been an easy task had they not worn the uniforms of
+aviators. But once these were noted, they were welcomed with smiles, and
+though at the first place they applied there was no room, the proprietor
+busied himself to such advantage that the boys were soon settled in a
+big double room with a fine view of a busy section of Paris.</p>
+
+<p>On every side was seen evidence of the joy and satisfaction felt at the
+showing made by the progress of the United States in her war programme.</p>
+
+<p>The stars and stripes were seen floating from many staffs, mingled with
+the tricolor of France and the English union jack. That Uncle Sam had
+at last gotten beyond the bounds of patience with a ruthless and
+sneaking enemy and was making energetic warfare against him was welcome
+news to those who had so long borne the unequal brunt of battle.</p>
+
+<p>"Americans? Ah, everything that I have is yours!" the hotel proprietor
+told Tom and Jack. "You have but to ask. And now come, I will show you
+the way to the cellar."</p>
+
+<p>"But we don't care to see the cellar," remarked Tom in wonder. "No doubt
+it is a very fine one, monsieur," he added in his best French, which was
+nothing to boast of. "No doubt it is most excellent, but we don't care
+for cellars."</p>
+
+<p>"Ah, I know, but it is for protection in case of an air raid that I show
+it to you. It is there we all take shelter. There have been raids, and
+there will be more. It is well to be prepared. It is a well-protected
+cellar."</p>
+
+<p>"Oh, well, that's different," observed Jack. "Come on, Tom, we'd better
+learn the best and quickest route to the basement. No telling when we
+might want to use it."</p>
+
+<p>They descended with the proprietor and saw that he had arranged the
+cellar with a false roof of beams, on top of which were sand bags. In
+case a bomb was dropped on the hotel or in its vicinity the cellar would
+offer almost certain protection.</p>
+
+<p>The boys arranged for a stay of at least a week in Paris, having told
+the proprietor their errand to the capital. By the time they had
+finished their dinner they found it was too late to set out in search of
+Mr. Raymond, as in the changed, war-time Paris little could be done in
+the evening. So Tom and Jack retired to their room and their bed.</p>
+
+<p>"Are you going right to the Rue Lafayette?" asked Jack of his chum, the
+next day.</p>
+
+<p>"Yes, and if we can't get any news of him there we'll appeal to the
+military authorities. I have a letter of introduction to persons high in
+authority from our captain."</p>
+
+<p>The boys hailed a taxicab and gave the chauffeur the necessary
+directions. They were bowling along through the beautiful streets of
+Paris, noting on all sides the warlike scenes, and their thoughts were
+busily occupied, when they suddenly became aware that something had
+happened.</p>
+
+<p>Like a thunderbolt from a clear sky there sounded a terrific explosion,
+and at no great distance. The concussion shook the ground, and they
+could feel the taxicab tremble under the shock, while the chauffeur
+instantly threw on all brakes, making the machine skid dangerously.</p>
+
+<p>"What is it? What's the matter?" yelled Jack.</p>
+
+<p>"Airship raid most likely!" shouted Tom. "Boches are dropping bombs on
+Paris! Oh, where's our cellar, Jack?"</p>
+
+<p>The taxicab driver jumped down and opened the door.</p>
+
+<p>"You had best alight, gentlemen," he said. "You must seek shelter."</p>
+
+<p>"Is it an airship raid?" asked Tom.</p>
+
+<p>"No, there is not an airship in sight. No such alarm has been sounded by
+the police. I fear the bombardment of Paris by the Germans has begun!"</p>
+
+
+
+<hr style="width: 65%;" />
+<h2><a name="CHAPTER_VI" id="CHAPTER_VI"></a>CHAPTER VI</h2>
+
+<h3>THE RUE LAFAYETTE RUINS</h3>
+
+
+<p>Tom Raymond and Jack Parmly alighted from the taxicab more quickly than
+they had gotten in. The chauffeur was anxiously scanning the sky.
+Excited men, women and children were rushing about, and yet it was not
+such excitement as might be caused by the first shelling of the
+beautiful city. It was more, as Tom said afterward, as though the
+populace had been taken by surprise by a new method in the same kind of
+warfare, for an occasional German Zeppelin or a bombing aircraft had,
+before this, dropped explosives. To these the French had become as much
+accustomed as one ever can to such terrible means of attack.</p>
+
+<p>But this was different. There was no sign of a Hun aircraft, and, as the
+chauffeur had said, no police warning had been sounded.</p>
+
+<p>"What is it?" asked Jack.</p>
+
+<p>"It is a bombardment, that is all I know," replied the taxicab driver.
+He spoke in French, a language which the two boys used fairly well,
+though, as has been said, their accent left much to be desired.</p>
+
+<p>"You had best seek shelter until it is over," went on the man. "I shall
+do so myself." He seemed to pause suggestively, and Jack handed him some
+money.</p>
+
+<p>"<i>Merci</i>," he murmured, and an instant later was careening down the
+street at full speed.</p>
+
+<p>"He isn't losing any time," said Jack.</p>
+
+<p>"No. And perhaps we hadn't better, either. Where'd that shell fall?"
+asked Tom.</p>
+
+<p>"I don't know, but it must have been somewhere about here, judging by
+the noise. Look, the crowd's over that way," and he pointed to the left.</p>
+
+<p>It was true. Careless of the danger of remaining in the open, men, and
+women, too, as well as some children, were rushing toward the place
+where, undoubtedly, the shell from the German gun had fallen.</p>
+
+<p>"Might as well take it in," suggested Jack. "I don't want to crawl down
+into a cellar or a subway quite yet, even if there's one around here; do
+you?"</p>
+
+<p>"No," answered Tom, "I don't. Go on, I'm with you."</p>
+
+<p>They followed the throng, but could not resist the impulse to gaze
+upward now and then for a possible sight of another shell, which, they
+half hoped, they might observe in time to run for shelter. But of course
+that would have been out of the question. However, quiet succeeded the
+din of the explosion, which had been close to the spot where the taxicab
+had stopped and the boys had alighted.</p>
+
+<p>Following the crowd, Tom and Jack came to a side street, and one look
+down it showed the havoc wrought by the German engine of death. The
+shell, of what kind or calibre could not be even guessed, had fallen on
+top of an establishment where a number of women and girls were employed.
+And many of these had been killed or wounded. There were heart-rending
+scenes, which it is not good to dwell upon. But, even in the terror and
+horror, French efficiency was at the fore.</p>
+
+<p>Ambulances were summoned, a guard was thrown about the building, and the
+work of aiding the injured and tenderly carrying out the dead was begun.
+A vast and excited throng increased in size about the building that had
+been hit and there was much excitement for a time.</p>
+
+<p>Tom and Jack managed to get to a place where they could get a view of
+the havoc wrought to the structure itself, and the first thing that
+impressed them was mentioned by Jack, who said:</p>
+
+<p>"They didn't use a very big shell, or there wouldn't have been such
+comparatively slight material damage done."</p>
+
+<p>"The force was mostly expended inside the building," suggested Tom.</p>
+
+<p>"Even so, if it had been a big shell, the kind they fired at Verdun and
+Liège, there'd be a crater here big enough to put a church in. As it is,
+only the two top stories are wrecked."</p>
+
+<p>"That's right," agreed Tom. "I wonder what sort of explosive they are
+using? Must have been one from a bombing aeroplane."</p>
+
+<p>"No, monsieur," interrupted a <i>gendarme</i> who was standing near. "Pardon,
+for speaking," he went on, with a salute, "but there was no airship
+observed over Paris at all. The shell came out of the clear sky."</p>
+
+<p>"But it couldn't have," insisted Jack, in reply to this policeman. "If
+the Germans are firing on Paris they must have some place from which to
+shoot their gun. Either on the ground or from an airship."</p>
+
+<p>"It was not an airship," insisted the <i>gendarme</i>. "Excuse me for
+insisting this to one who is in the air service," and he pointed with
+pride to the uniform the boys wore, "but I have seen several air raids,
+and I know! There was no airship seen, or I would have blown the alarm,"
+and he motioned to his whistle which he carried for that purpose.</p>
+
+<p>"It could have come from an immense airship, so high up as to be beyond
+observation," suggested Jack. "That's possible. Probably the Germans
+didn't want to be bombarded themselves by aircraft guns here, and they
+flew high."</p>
+
+<p>The police officer shook his head. He was not convinced.</p>
+
+<p>"But, man, how else could it be?" asked Tom, in some heat. "The Huns
+have to rest their gun somewhere, and you&mdash;Say, Jack!" he suddenly
+exclaimed, his face paling slightly, "you don't suppose they have broken
+through, do you?"</p>
+
+<p>"Through our lines about Paris? Never!" cried the police officer. "They
+shall not pass! Our brave soldiers have said it, and they will maintain
+it. They shall not pass!"</p>
+
+<p>"And yet," mused Tom, as he looked at the rescue work going on, "what
+other explanation is there? It's a bombardment of Paris all right, by
+German shells. If they don't come from an aeroplane, high up, they must
+come&mdash;"</p>
+
+<p>His words were drowned by another great concussion, but farther off. The
+ground trembled, but there was no sign of flying debris.</p>
+
+<p>"Another!" cried the <i>gendarme</i>. "There goes the gun again!"</p>
+
+<p>"I didn't hear any gun," observed Jack. "What we heard was the explosion
+of the shell. Look up, Tom, and see if there's a Hun plane in sight. If
+there is, pity we haven't our machines right now."</p>
+
+<p>The boys carried, slung over their shoulders, powerful binoculars, and
+with these they swept the sky. Others about them were doing the same. By
+this time the most seriously injured had been carried to the hospitals,
+and the dead had been removed, while those only slightly hurt, as well
+as those in the factory not at all injured, were telling their
+experiences. The second explosion seemed to create great terror.</p>
+
+<p>"There isn't a sign of a hostile plane," said Tom, as he swept the sky
+with his glasses.</p>
+
+<p>"I can't see any either," observed Jack. "And yet&mdash;"</p>
+
+<p>There sounded the unmistakable roar of an aircraft's propeller.</p>
+
+<p>"There she is!" cried some one.</p>
+
+<p>But it was one of the first of a series of French planes that had
+hastily ascended to search the heavens for a sight of the supposed
+German craft that had dropped the bombs.</p>
+
+<p>"What a chance we're missing!" murmured Jack.</p>
+
+<p>"Yes," agreed Tom. "But they're going to have some flight before they
+locate that Hun. There isn't so much as a speck in the sky except the
+French craft."</p>
+
+<p>"Let's go and see where that other explosion was," suggested Jack, when
+they had observed several of the French planes scurrying to and fro over
+the city, climbing higher and higher in search of the enemy.</p>
+
+<p>"I'm with you," announced Tom. "I wonder what dad thinks of this?"</p>
+
+<p>"It'll be something new for him," said Jack. "He'll have a good chance
+to see how his stabilizer works, if they're using it on these planes
+here. And maybe he can invent a better one."</p>
+
+<p>"Perhaps," returned Tom. "But, Jack, do you know I'm worried about one
+thing."</p>
+
+<p>"I have more than that on my mind, Tom. There are mighty serious times
+all about us, and it's terrible to think of those poor women and girls
+being killed like rats in a trap. I'd just like to be in my plane, and
+with a full gun, and then have a go at the Hun who did this."</p>
+
+<p>"So would I," agreed Tom, as they made their way out of the crowd and in
+the direction in which many of the populace were hurrying to go to the
+scene of the second explosion. "But, Jack, do you know I shouldn't be
+surprised to learn that the shell was not from an airship at all."</p>
+
+<p>"Where would it be from then?"</p>
+
+<p>"The Germans may have massed such a lot of troops at some point opposite
+the French lines, that they have broken through and have brought up
+some of their heavy guns."</p>
+
+<p>Jack shook his head.</p>
+
+<p>"I don't believe they could do it," he said. "You know the nearest
+German line is about seventy miles from Paris. If they had started to
+break through, and had any success at all, the news would have reached
+here before this. And reinforcements would be on the way. No, it can't
+be. There must be some other explanation."</p>
+
+<p>"But what is it?" asked Tom. "They've got to get nearer than seventy
+miles to bombard Paris. You know that."</p>
+
+<p>"I don't think I really <i>know</i> anything about this war," said Jack
+simply. "So many strange, things have happened, so many old theories
+have been discarded, and so many new things have been done that we don't
+know where we are."</p>
+
+<p>"Well that's true. And yet how could the Germans get near enough to
+bombard Paris without some word of it coming in?"</p>
+
+<p>"I don't know. But the fact remains. Now let's get to where the second
+shell fell. Maybe we can see a fragment of it and&mdash;"</p>
+
+<p>Once again the words were interrupted by an explosion. This time it was
+closer and the shock was greater.</p>
+
+<p>"That's the third!" cried Jack.</p>
+
+<p>"Yes," added Tom, looking at his watch, "and it's just half an hour
+since the first one fell. That indicates they're firing every fifteen
+minutes. Jack, there's something weird about this."</p>
+
+<p>"You're right. That last one came rather close, too. I wonder where it
+fell?"</p>
+
+<p>A man, passing them, running in a direction away from the sound of the
+last explosion, heard Jack's question. He paused long enough to say;
+"That shell fell in Rue Lafayette. Several buildings are in ruins. Many
+have been killed! It is terrible!"</p>
+
+<p>"Rue Lafayette!" gasped Jack. "That&mdash;"</p>
+
+<p>"That's where my father is supposed to be staying!" exclaimed Tom.
+"Come! We must see what happened!"</p>
+
+
+
+<hr style="width: 65%;" />
+<h2><a name="CHAPTER_VII" id="CHAPTER_VII"></a>CHAPTER VII</h2>
+
+<h3>TOM'S FATHER</h3>
+
+
+<p>With anxious hearts the Air Service boys ran on. There was no need to
+ask their way, for they had but to follow the throng toward the scene of
+the most recent exhibition of the Hun's frightfulness and horror.</p>
+
+<p>As they drew near the Rue Lafayette, where Mr. Raymond had said he
+intended to stay while in Paris, the boys were halted by an officer on
+the outskirts of the throng.</p>
+
+<p>"Pardon, but you may not go farther," he said, courteously enough.
+"There is danger. We are about to sound the alarm so that all may take
+to shelter. The Boches are raiding Paris again."</p>
+
+<p>"We know it," said Tom. "But it is no idle curiosity that takes us on."</p>
+
+<p>"No?" politely questioned the policeman.</p>
+
+<p>"No. I am seeking my father. He wrote to me that he would stop in the
+Rue Lafayette, and I have not heard from him since. I was told that the
+last shell fell in that street."</p>
+
+<p>"It did," assented the officer, "and it demolished two houses and part
+of another. Many were killed and injured."</p>
+
+<p>"Then I must see if my father is among them!" insisted the young
+aviator.</p>
+
+<p>"Pardon, monsieur, it is not possible. I have my instructions, and&mdash;"</p>
+
+<p>He stopped, and for the first time seemed to become aware of the
+uniforms worn by Tom and Jack. Then the officer saluted as though proud
+to do it.</p>
+
+<p>"Ah," he murmured. "Of the Lafayette Escadrille! You may go where you
+will. Only I hope it is not into danger," he said, as he drew aside for
+them to pass. "Pardon, I did not at first sense who you were. France
+owes you much, messieurs. Keep your lives save for her!"</p>
+
+<p>"We will," promised Tom, as he hurried on, followed by Jack.</p>
+
+<p>They came to the head of the street they sought, and, looking down it,
+beheld ruins greater than they had seen before. As the officer had said,
+two buildings had been completely demolished, and a third partly so, the
+wreckage of all mingling. And amid these ruins police and soldiers were
+working frantically to get out the injured and remove the dead, of whom
+there was a sad number.</p>
+
+<p>Tom's face was white, but he kept his nerve. He had been through too
+many scenes of horror, had been too near death too often of late, as had
+his chum, to falter now, even though his father might be among those
+buried in the wreckage caused by the German shell.</p>
+
+<p>"Do you know what number your father was to stop at?" asked Jack.</p>
+
+<p>"Yes, I have his letter," Tom answered. "I'm afraid, Jack, it was in one
+of those buildings that have been blown apart."</p>
+
+<p>"No, Tom!"</p>
+
+<p>"I'm afraid so. But, even at that, he may have had a chance for his
+life. He may have been out, or, after all, he may not have arrived yet.
+I'm not going to give up hope until I have to."</p>
+
+<p>"That's the way to talk, old man. I'm with you to the last."</p>
+
+<p>They pressed on, and populace and officers alike gave way before them as
+they saw the uniforms.</p>
+
+<p>"We've got to help!" declared Tom. "We must pitch in, Jack, and lend a
+hand here. The soldiers seem to be in charge. Let's report to the
+commanding officer and offer our services."</p>
+
+<p>"But your father?"</p>
+
+<p>"That's the best way to find him if he's in those ruins. Let us help get
+the unfortunates out. I hope I don't find him, but I must make sure."</p>
+
+<p>Making their way through the press of people, which, under order of the
+police and military authorities, had begun to disperse in some small
+measure, Tom and Jack reported to the officer in charge, giving him
+their names and rank, at the same time showing their papers.</p>
+
+<p>"We want to help," the lads told him.</p>
+
+<p>"And I ask no better," was the quick response. "There are dead and dying
+under that pile. They must be gotten out."</p>
+
+<p>And then began heart-rending scenes. Tom and Jack did valiant work in
+carrying out the dead and dying, in both of which classes were men,
+women and children.</p>
+
+<p>The German beasts were living up to the mark they had set for themselves
+in their war of frightfulness.</p>
+
+<p>Each time a dead or injured man was reached, to be carried out for
+hospital treatment or to have the last sad rites paid him, Tom nerved
+himself to look. But he did not see his father, and some small measure
+of thankfulness surged into his heart. But there were still others
+buried deep under the ruins, and it would be some time before their
+bodies, dead or alive, could be got out.</p>
+
+<p>As the soldiers and police worked, on all sides could be heard
+discussions as to what new form or manner of weapon the Germans were
+using thus to reach Paris. Many inclined to the theory that it was a new
+form of airship, flying so high as to be not only beyond ordinary
+observation, but to be unreachable by the type of planes available at
+Paris.</p>
+
+<p>"If we could only find a piece of the shell we could come nearer to
+guessing what sort of gun fired it," remarked Tom, as the two Air
+Service boys rested a moment from their hard, terrible labors.</p>
+
+<p>"Do you mean if it was dropped from an airship it wouldn't have any
+rifling grooves on it?" asked Jack.</p>
+
+<p>"That's it. A bomb, dropped from an aeroplane, would, very likely, be
+only a sort of round affair, set to explode on contact or by a time
+fuse. But if it was a shell fired from a long-range gun, there might be
+enough of it left, after the explosion, to observe the rifling."</p>
+
+<p>"There isn't a gun with a range long enough to reach Paris from the
+nearest German lines, unless they have broken through," said Jack.</p>
+
+<p>"Well, the last may have happened; though I should think we'd have got
+some word of it in that case. There'd be fierce fighting if the Germans
+tried that, and we'd rush reinforcements out in taxicabs as the Paris
+soldiers went out once before."</p>
+
+<p>"Do you think then," asked Jack, as they went back, after their brief
+respite, to their appalling labors, "that they have a gun long enough
+to fire from their nearest point, which is about seventy miles from this
+city?"</p>
+
+<p>"I don't know what to think," remarked Tom. "It seems like a wild dream
+to speak of a gun that can shoot so far; and yet reality is over-topping
+many wild dreams these days. I'm going to reserve judgment. My chief
+concern now, though of course I'm not going to let it interfere with my
+work, is to find my father. If he should have been in here, Jack&mdash;"</p>
+
+<p>Tom did not finish, but his chum knew what he meant, and sympathized
+with his unexpressed fear for the safety of Mr. Raymond.</p>
+
+<p>Digging and delving into the ruins, they brought out the racked and
+maimed bodies, and there was more than one whose eyes were wet with
+tears, while in their hearts wild and justifiable rage was felt at the
+ruthless Germans.</p>
+
+<p>Ten had been killed and nearly twice that number wounded in the third
+shell from the Hun cannon.</p>
+
+<p>From a policeman Tom learned that one of the two buildings that had been
+demolished was the number given by Mr. Raymond as the place he would
+stay.</p>
+
+<p>"The place he picked out may have been full, and he might have gone
+somewhere else," said Tom. "We've got to find out about that, Jack."</p>
+
+<p>"That's right. I should think the best person, or persons, to talk to
+would be the janitors, or '<i>concierges</i>,' as they call 'em here."</p>
+
+<p>"I'll do that," responded Tom.</p>
+
+<p>Aided by an army officer, to whom the boys had recommended themselves,
+not only by reason of their rank, but because of their good work in the
+emergency, they found a man who was in charge of all three buildings as
+a renting agent. Fortunately he had his books, which he had saved from
+the wreck.</p>
+
+<p>"You ask for a Monsieur Raymond," he said, as he scanned the begrimed
+pages. "Yes, he was here. It was in the middle building he had a room."</p>
+
+<p>"In the one that was destroyed?" asked Tom, his heart sinking.</p>
+
+<p>"I regret to say it&mdash;yes."</p>
+
+<p>"Then I&mdash;then it may be all up with poor old dad!" and Tom, with a
+masterful effort, restrained his grief, while Jack gripped his chum's
+hand hard.</p>
+
+
+
+<hr style="width: 65%;" />
+<h2><a name="CHAPTER_VIII" id="CHAPTER_VIII"></a>CHAPTER VIII</h2>
+
+<h3>WHERE IS MR. RAYMOND?</h3>
+
+
+<p>Tom Raymond, having gone through a hard school since he began flying for
+France, soon recovered almost complete mastery of himself. The first
+shock was severe, but when it was over he was able to think clearly.
+Indeed the faculty of thinking clearly in times of great danger is what
+makes great aviators. For in no other situation is a clear and quick
+brain so urgently needed.</p>
+
+<p>"Well, I'm sure of one thing, Jack," said Tom, as they walked away from
+the fateful ruins. "Of those we helped carry out none was my father. He
+wasn't among the injured or dead."</p>
+
+<p>"I'm sure of that, too. Still we mustn't count too much on it, Tom. I
+don't want you to have false hopes. We must make sure."</p>
+
+<p>"Yes, I'm going to. We'll visit the hospitals and morgues, and talk with
+the military and police authorities. In these war times there is a
+record of everybody and everything kept, so it ought to be easy to trace
+him."</p>
+
+<p>"He arrived all right, that's settled," declared Jack. "The agent's
+record proves that."</p>
+
+<p>"Yes. I'd like to have a further talk with that agent before we set out
+to make other inquiries."</p>
+
+<p>This Tom was able to bring about some time later that day. The agent
+informed the lad that Mr. Raymond, contrary to his expectations, had
+arrived only the day before. Where he had been delayed since arriving in
+Europe was not made clear.</p>
+
+<p>"But was my father in the building at the time the shell struck here?"
+asked Tom. "That's what I want to know."</p>
+
+<p>Of this the man could not be certain. He had seen Mr. Raymond, he said,
+an hour or so before the bombardment, and the inventor was, at that
+time, in his room. Then he had gone out, but whether he had come back
+and was in the house when the shell struck the place, could not be said
+with certainty.</p>
+
+<p>But if he had been in his apartment there was little chance that he had
+been left alive, for the explosion occurred very near his room,
+destroying everything. Tom hoped, later, to find some of his father's
+effects.</p>
+
+<p>"There is just a chance, Jack," said the inventor's son, "that he wasn't
+in his room."</p>
+
+<p>"A good chance, I should say," agreed the other. "Even if he had
+returned to his room, and that's unlikely, he may have run out at the
+sound of the first explosion, to see what it was all about."</p>
+
+<p>"I'm counting on that. If he was out he is probably alive now. But if he
+was in his room&mdash;"</p>
+
+<p>"There would be some trace of him," finished Jack.</p>
+
+<p>"And that's what we've got to find."</p>
+
+<p>The police and soldiers were only too willing to assist Tom in his
+search for his father. The ruins, they said, would be carefully gone
+over in an endeavor to get a piece of the German shell to ascertain its
+nature and the kind of gun that fired it. During that search some trace
+might be found of Mr. Raymond.</p>
+
+<p>It did not take long to establish one fact&mdash;that the inventor's body was
+not among the dead carried out. Nor was he numbered with the injured in
+the hospitals. Careful records had been kept, and no one at all
+answering to his description had been taken out or cared for.</p>
+
+<p>And yet, of course, there was the nerve-racking possibility that he
+might have been so terribly mutilated that his body was beyond all human
+semblance. The place where his room had been was a mass of splintered
+wood and crumbled masonry. There was none of his effects discernible,
+and Tom did not know what to think.</p>
+
+<p>"We've just got to wait," he said to Jack, late that afternoon, when
+their search of the hospitals and morgues had ended fruitlessly.</p>
+
+<p>Meanwhile the French airmen had been scouring the sky for a sight of the
+German craft that might have released the death-dealing bombs on the
+city. But their success had been nil. Not a Hun had been sighted, and
+one aviator went up nearly four miles in an endeavor to locate a hostile
+craft.</p>
+
+<p>Of course it was possible that a super-machine of the Huns had flown
+higher, but this did not seem feasible.</p>
+
+<p>"There is some other explanation of the bombardment of Paris, I'm sure,"
+said Tom, as he and Jack went to their lodgings. "It will be a surprise,
+too, I'm thinking, and we'll have to make over some of our old ideas and
+accept new ones."</p>
+
+<p>"I believe you're right, Tom. But say, do you remember that fellow we
+saw in the train&mdash;the one I thought was a German spy?"</p>
+
+<p>"To be sure I remember him and his <i>metzel suppe</i>. What about him? Do
+you see him again?" and Tom looked out into the street from the window
+of their lodging.</p>
+
+<p>"No. I don't see him. But he may have had something to do with shelling
+the city."</p>
+
+<p>"You don't mean he carried a long-range gun in his pocket, do you,
+Jack?" and Tom smiled for the first time since the awful tragedy.</p>
+
+<p>"No, of course not. Still he may have known it was going to happen, and
+have come to observe the effect and report to his beastly masters."</p>
+
+<p>"He'd be foolish to come to Paris and run the chance of being hit by his
+own shells."</p>
+
+<p>"Unless he knew just where they were going to fall," said Jack.</p>
+
+<p>"You have a reason for everything, I see," remarked Tom. "Well, the next
+time we go to headquarters we'll find out what they learned of this
+fellow. You know we started the secret service agents on his trail."</p>
+
+<p>"Yes, I know. Well, I was just sort of wondering if he had anything to
+do with the bombardment of Paris. You've got to look for German spies
+now, even under your bed at night."</p>
+
+<p>The boys felt they could do nothing more that day toward finding Mr.
+Raymond. A more detailed and careful search of the ruins might reveal
+something. Until this was accomplished nothing could be done.</p>
+
+<p>They ate a late supper, without much in the way of appetites, it must be
+confessed, and then went out in the streets of Paris. There seemed to be
+few signs of war, aside from the many soldiers, and even the
+bombardment of a few hours earlier appeared to have been forgotten. But
+of course there was grief in many hearts.</p>
+
+<p>It was early the next morning, when Tom and Jack were getting ready to
+go back to the ruins in the Rue Lafayette, that, as they left their
+lodgings, they heard in the air above them the familiar sounds of
+aeroplanes in flight, and the faint popping of machine guns, to which
+was added the burst of shrapnel.</p>
+
+<p>"Look!" cried Jack. "It's a battle in the air. The Huns are making
+another raid. Now we'll see how they bomb the city."</p>
+
+<p>But it did not turn out to be that sort of raid. The German craft were
+flying low, apparently to get a view of the havoc wrought the day
+before. Possibly photographs were being taken.</p>
+
+<p>But the French aeroplanes were ready for the foe, and at once arose to
+give battle, while the anti-aircraft guns roared out a stern order to
+retreat. It was a battle above the city and, more than once, Tom and
+Jack wished they could be in it.</p>
+
+<p>"We'll have to get back to our hangars soon," mused Tom, as they watched
+the fight. "We can't be slackers, even if I can't find my father," he
+added bravely.</p>
+
+<p>The French planes were too much for the Germans, and soon drove them
+back beyond the Hun lines, though perhaps not before the enemy aviators
+had made the observations desired.</p>
+
+<p>"Well, they didn't see much," remarked Jack. "As far as any real damage
+was done to Paris it doesn't count, from a military standpoint."</p>
+
+<p>"No, you're right," agreed Tom. "Of course they have killed some
+noncombatants, but that seems to be the Boche's principal form of
+amusement. As for getting any nearer to the capture of Paris this way,
+he might as well throw beans at the pyramids. It's probably done for the
+moral, or immoral, effect."</p>
+
+<p>And this seemed to be the view taken of it by the Paris and London
+papers. The method of bombardment, however, remained a mystery, and a
+baffling one. This was a point the military authorities wished to clear
+up. To that end it was much to be desired that fragments of the shell
+should be found. And to find them, if possible, a careful search was
+made, not only in the ruins of the Rue Lafayette, but at the other two
+places where the explosions had occurred.</p>
+
+<p>In no place, however, was a large enough fragment found to justify any
+conclusive theories, and the Parisians were forced to wait for another
+bombardment&mdash;rather a grim and tense waiting it was, too.</p>
+
+<p>But the careful search of the Rue Lafayette ruins proved one thing. The
+body of Tom's father was not among them, though this did not make it
+certain that he was alive. He may have been totally destroyed, and this
+thought kept Tom from being able to free his mind of anxiety. He dared
+not cable any news home, and all he could do was to keep on hoping.
+These were anxious days for him and Jack.</p>
+
+<p>Their leave of absence had been for a week only, but under the
+circumstances, and as it was exceptionally quiet on their sector, they
+were allowed to remain longer. Tom wanted to make a more thorough search
+for his father, and the police and military authorities helped him. But
+Mr. Raymond seemed to have completely disappeared. There was no trace of
+him since the agent for the Rue Lafayette buildings had seen him leave
+his room just prior to the falling of the shell.</p>
+
+<p>Jack inquired about the man he suspected of being a German spy. The
+secret service men had him under observation, they reported, but, as
+yet, he had not given them any cause to arrest him. They were waiting
+and watching.</p>
+
+<p>Meanwhile active preparations were under way, not only to discover the
+source of the bombardment of Paris, but to counteract it. Extra
+anti-aircraft guns, of powerful calibre, were erected in many places
+about the city, and more airmen were summoned to the defense.</p>
+
+<p>As yet there had been no resumption of the bombardment, and there were
+hopes that the German machine, whatever it was, had burst or been put
+out of commission. But on the second day of the second week of the boys'
+stay in Paris, once more there was the alarm and the warning-from the
+soldiers and police, and again came that explosion.</p>
+
+<p>The bombardment of Paris was being renewed!</p>
+
+
+
+<hr style="width: 65%;" />
+<h2><a name="CHAPTER_IX" id="CHAPTER_IX"></a>CHAPTER IX</h2>
+
+<h3>VARIOUS THEORIES</h3>
+
+
+<p>Two things were at once apparent to Tom and Jack as they hurried out of
+their <i>pension</i>. One was that the people of Paris were not seeking
+shelter after the warnings as quickly as they had done at first, and the
+other was that there was evident curiosity on all sides to see just what
+damage would be done, and from which direction it would come. With an
+almost reckless disregard for their safety, if not for their lives, the
+Parisians fairly flocked out of doors to see the results of the Huns'
+bombardment. It was in vain that the police and military urged them to
+seek safety in cellars or the places provided.</p>
+
+<p>This time only one shell fell near enough to Tom and Jack to make the
+explosion heard, and that was so faint as to indicate that it was some
+distance off. What damage had been done could only be guessed at.</p>
+
+<p>"But we'll find out where it is, and go take a look," said Jack.</p>
+
+<p>"Maybe it'll hit right around here if we stay," suggested his chum.</p>
+
+<p>"Well, I'm not taking that chance," Jack went on. "Let's find out where
+it landed this time."</p>
+
+<p>This they could do through their acquaintance with the military
+authority of the district where they were then staying. A telephonic
+report was at once received, giving the quarter where the shell had
+landed. It had fallen in one of the public squares, and though a big
+hole had been torn in the ground and pavement, and several persons
+killed and wounded, no material damage had been done. As for any
+military effect of the shell, it was nil.</p>
+
+<p>The firing was done in the early evening hours, and Tom and Jack learned
+that, almost to the second, the shots were fifteen minutes apart.</p>
+
+<p>There was one theory that an underground passage had been made in some
+manner to within a comparatively few miles of Paris, and from that point
+an immense mortar sent up the shells in a long trajectory.</p>
+
+<p>Another theory was that traitors had let the Germans through the French
+lines at a certain place, so they could get near enough to Paris to
+bombard it.</p>
+
+<p>And of course the gigantic airship theory had its adherents.</p>
+
+<p>But, for a time at least, no one would admit the possibility of a gun
+with range sufficient to shoot into Paris from the nearest German lines.
+The range, sixty-odd miles, seemed too great for practical belief,
+however nicely it might work out in theory.</p>
+
+<p>"And you must remember that the gun, if gun it is, couldn't be in the
+very first German line," said Tom, who had studied ordnance. "It must be
+at least ten miles back, to allow for sufficient protection from the
+French guns. That would make it shoot about seventy-two miles, and I
+don't believe any gun on earth could do it!"</p>
+
+<p>"Neither do I," added Jack. "We've got to dope out something else. But
+this isn't finding your father, Tom."</p>
+
+<p>"I know it, and I don't mind admitting I'm clean discouraged about him,
+Jack. If he's alive why doesn't he send me some word? He must know where
+I am, and, even if he doesn't know I'm in Paris, they would forward any
+message he might send to our aeroplane headquarters."</p>
+
+<p>"That's right. But what are you going to do about it?"</p>
+
+<p>"I hardly know. He may still be in Paris, but it's such a big city that
+it's hard to find him. Then, too, I'm thinking of something else."</p>
+
+<p>"What's that, Tom?"</p>
+
+<p>"Well, dad may not want us to know where he is."</p>
+
+<p>"Why in the world would he want such a thing as that?"</p>
+
+<p>"Well, he might be followed, or bothered by spies. Perhaps he has come
+over to do some special work for the French or English army people.
+Maybe a spy was after him just before the big German gun wrecked his Rue
+Lafayette house. He may have considered this a good chance to play dead,
+and that's why he doesn't send some word to me."</p>
+
+<p>"That's a good theory. But it isn't very comforting."</p>
+
+<p>"No, but there isn't much comfort in war times. We've got to make the
+best of it."</p>
+
+<p>"I guess you're right, Tom. Now do you want to go look at the latest
+work of the Hun?"</p>
+
+<p>"Might as well. The bombardment seems over for the night."</p>
+
+<p>"I wonder why it is they don't fire after dark."</p>
+
+<p>"Probably afraid of giving the location of their cannon away by the
+flashes. They'd be seen at night; but during the day, if they used
+smokeless powder, or a smoke screen in case they can't get smokeless
+powder for such a big gun, it would be hard to locate the place where
+the shots come from. So we're comparatively safe after dark, it seems."</p>
+
+<p>Later this was not to prove to be the case, but it was when Tom spoke.</p>
+
+<p>The boys went to the section of the city in which the last shells had
+fallen. While comparatively little damage had been done, a number of
+persons had been killed and injured, children among them. Some fragments
+of the shells were picked up, but not enough to make certain any
+particular theory in regard to the gun.</p>
+
+<p>"But if it's a gun, where could it be placed?" queried Tom of an
+officer. "The Germans haven't broken through, have they?"</p>
+
+<p>The French officer shook his head.</p>
+
+<p>"No. And please God they will never get through," he said. "But there is
+a gun somewhere, I am sure of that."</p>
+
+<p>"Do you mean to say within ten or fifteen miles of Paris?" Jack wanted
+to know.</p>
+
+<p>"I can not be sure. It is true there may have been traitors. We have
+them to contend with as well as spies. But our line is intact, and at no
+point along it, near enough to it to fire into Paris from an ordinary
+gun, can the Germans be found."</p>
+
+<p>"Then it must be an extraordinary gun," suggested Jack.</p>
+
+<p>"It may well be&mdash;perhaps it is. Yet, as I said, there may have been
+traitors. There may be a gun concealed somewhere closer to Paris than we
+dream. But we shall find it, messieurs! Who knows? Perhaps you may be
+the very ones yourselves to locate it, for we are depending on you
+soldiers of the air."</p>
+
+<p>And it was not long before this talk came back to Tom and Jack with
+impressive recollection.</p>
+
+<p>And meanwhile the bombardment of Paris went on, usually during the late
+afternoon or early morning hours&mdash;never at night, as yet.</p>
+
+<p>Yet with all the frightfulness of which the unscrupulous Huns were
+capable, it was impossible to dampen for long the spirits of the French.
+Soon they grew almost to disregard the falling shells from the hidden
+German gun. Of course there were buildings destroyed, and lives were
+lost, while many were frightfully maimed. But if Germany depended on
+this, as she seemed to, to strike terror to the hearts of the brave
+Frenchmen the while a great offensive was going on along the western
+front, it failed. For the people of Paris did not allow themselves to be
+disheartened, any more than the people of London did when the Zeppelins
+raided them.</p>
+
+<p>Indeed one Paris paper even managed to extract some humor out of the
+grim situation. For one day, following the bombardment, a journal
+appeared with "scare" headlines, telling about eleven "lives" being
+lost. But when one read the account it was discovered that the lives
+were those of chickens.</p>
+
+<p>And this actually happened. A shell fell on the outlying section and
+blew up a henhouse, killing nearly a dozen fowls and blowing a big hole
+in the ground.</p>
+
+<p>There were other occasions, too, when the seemingly superhuman
+bombardment was not worth the proverbial candle. For the shells fell in
+sections where no damage was done, and where no lives paid the toll.
+Once a shell went through a house, passing close to an aged woman, but
+not hurting her, to explode harmlessly in a field near by.</p>
+
+<p>And it was with such accounts as these that the Paris papers kept up the
+spirits of the inhabitants. Meanwhile the Germans kept firing away at
+quarter-hour intervals, when the gun was in action.</p>
+
+<p>"I wonder if there is any chance of us getting in at the game?"
+questioned Jack of Tom one night.</p>
+
+<p>"I shouldn't be surprised. As that officer said, they'll have to depend
+on the aircraft to locate the gun, I'm thinking."</p>
+
+<p>"And you think we have a chance?"</p>
+
+<p>"I don't see why not," replied Tom. "We've been off duty long enough.
+I'd like to get back behind the propeller again, and with a drum or two
+of bullets to use in case we sight a Hun plane. Let's go and send word
+to our captain that we've had enough of leave, and want to go out
+again."</p>
+
+<p>"All right. But what about your father?"</p>
+
+<p>"Well, I don't know what to say," answered Tom. "I'm about convinced
+that he wasn't killed, or even hurt, in any of the bombardments of
+Paris. But where he is I don't know. I guess, as a matter of duty to
+France, I'll have to let my private affairs go and&mdash;"</p>
+
+<p>At that instant there sounded an explosion the character of which the
+two boys well knew by this time.</p>
+
+<p>"The big gun again!" cried Jack.</p>
+
+<p>"Yes, and they're firing after dark!" added Tom. "This may be just the
+chance the airmen have been waiting for&mdash;to locate the piece by the
+flashes. Come on out and see what's doing!"</p>
+
+<p>Together they rushed from their room.</p>
+
+
+
+<hr style="width: 65%;" />
+<h2><a name="CHAPTER_X" id="CHAPTER_X"></a>CHAPTER X</h2>
+
+<h3>THE "DUD"</h3>
+
+
+<p>Much the same sort of scene was going on in the streets of Paris as Tom
+and Jack had witnessed when first the populace realized that they were
+under fire from a mysterious German cannon. There was the initial
+alarm&mdash;the warnings sounded by the police and soldiers, warnings which
+were different from those indicating a Zeppelin or aircraft raid, and
+then the hurry for cover.</p>
+
+<p>But it was noticeable that not so many of the people rushed for a secure
+hiding place as had done so at first.</p>
+
+<p>"They're not so afraid of the big gun as they were," observed Jack, as
+he hurried along with his chum.</p>
+
+<p>"No. Though it's just as well to be a bit cautious, I think. The people
+of Paris are beginning to lose fear because they see that the German
+shells don't do as much damage as might be expected."</p>
+
+<p>"You're right there, Tom," said Jack. "The shells are rather small, to
+judge by the damage they do. I wonder why that is?"</p>
+
+<p>"Probably their gun, or guns, can't fire any larger ones such a long
+distance, or else their airships can't carry 'em up above the clouds to
+drop on the city."</p>
+
+<p>"Then you still hold to the airship theory?"</p>
+
+<p>"Well, Jack, I haven't altogether given it up. I'm open to conviction,
+as it were. Of course I know, in theory, a gun can be made that will
+shoot a hundred miles, if necessary, but the cost of it, the cost of the
+charge and the work of loading it, as well as the enormous task of
+making a carriage or an emplacement to withstand the terrific recoil,
+makes such a gun a military white elephant. In other words it isn't
+worth the trouble it would take&mdash;the amount of damage inflicted on the
+enemy wouldn't make it worth while."</p>
+
+<p>"I guess you're right, Tom. And yet such a gun would make a big scare."</p>
+
+<p>"Yes, and that's what the Germans are depending on, more than anything
+else."</p>
+
+<p>"But still don't you think the French will have to do something toward
+silencing the gun?"</p>
+
+<p>"Indeed I do! And I haven't a doubt but the French command is working
+night and day to devise some plan whereby the gun can be silenced."</p>
+
+<p>"There go the aviators now, out to try to find the big cannon,"
+observed Jack, as he gazed aloft.</p>
+
+<p>Soaring over Paris, having hastened to take the air when the signal was
+given, were a number of planes, their red, white and blue lights showing
+dimly against the black sky. They were off to try to place the big gun,
+if such it was, or discover whether or not some Hun plane was hovering
+over the city, dropping the bombs.</p>
+
+<p>As Jack and Tom hastened on, in the wake of the crowd, which was
+hurrying toward the place where the latest shells had fallen, again came
+a distant explosion, showing that the gun had been fired again.</p>
+
+<p>"Fifteen-minute interval," announced Tom, looking at his watch. "They're
+keeping strictly to schedule."</p>
+
+<p>"Night firing is new for the big gun," said Jack. "I do hope they'll be
+able to locate the cannon by the flashes."</p>
+
+<p>"It isn't going to be easy," asserted Tom.</p>
+
+<p>"Why not?"</p>
+
+<p>"Because you can make up your mind if the Germans were afraid to fire
+the piece at night at first for fear of being discovered, and if now
+they are firing after dark, they have some means of camouflaging the
+flash. In other words they have it hidden in some way."</p>
+
+<p>"Well, I suppose you're right. But say, Tom, old man! what wouldn't I
+give to be able to be up in the air with those boys now?" and Jack
+motioned to the scouts who were flitting around in the dark clouds,
+seeking for that which menaced the chief city of the French nation.</p>
+
+<p>"I'd like to be there myself," said Tom. "And if this keeps up much
+longer I'm going to ask permission for us to go up and see what we can
+do."</p>
+
+<p>"Think they'll let us?"</p>
+
+<p>"Well, they can't any more than turn us down. And we've got to get at it
+in a hurry, too, or we'll have to report back at our regular station. We
+aren't doing anything here, except sit around."</p>
+
+<p>"No, we must get busy, that's a fact," said Jack. "It's about time we
+downed some Hun scout, or broke up one of their 'circus' attacks. I've
+almost forgotten how a joy stick feels."</p>
+
+<p>A "joy stick" is a contrivance on an aeroplane by the manipulation of
+which the plane is held on a level keel. If the joy stick control is
+released, either by accident (say when the pilot is wounded in a fight),
+or purposely, the plane at once begins to climb, caking its passenger
+out of danger.</p>
+
+<p>Once the joy stick is released it gradually comes back toward the
+pilot. The machine climbs until the angle formed is too great for it to
+continue, or for the motor to pull it. Then it may stop for an instant
+when the motor, being heavier, pulls the plane over and there begins the
+terrible "nose spinning dive," from which there is no escape unless the
+pilot gets control of his machine again, or manages to reach the joy
+stick.</p>
+
+<p>"Well, we'll have to get in the game again soon," said Tom. "But what do
+you say to taking a taxi? This explosion is farther than I thought."</p>
+
+<p>Jack agreed, and they were soon at the place where the last German shell
+had fallen&mdash;that is as near as the police would permit.</p>
+
+<p>A house had been struck, and several persons, two of them children,
+killed. But, as before, the military damage done was nothing. The
+Germans might be spreading their gospel of fear, but they were not
+advancing their army that way.</p>
+
+<p>As Tom and Jack stood near the place where a hole had been blown through
+the house, another explosion, farther off, was heard, and there was a
+momentary flare in the sky that told of the arrival of another shell.</p>
+
+<p>For a few seconds there was something like a panic, and then a voice
+struck up the "Marseillaise," and the crowd joined in. It was their
+defiance to the savage Hun.</p>
+
+<p>A few shots were fired by the Germans, but none of them did much damage,
+and then, as though operating on a schedule which must not, under any
+circumstances, be changed, the firing ceased, and the crowds once more
+filled the streets, for it was yet early in the night.</p>
+
+<p>The next morning the boys went to report, as they did each day,
+expecting that they might be called back to duty. They also found, after
+being told that their leave was still in effect, that some of the
+aviators who had gone up the night before, to try to locate the German
+gun, were on hand.</p>
+
+<p>"Now we can ask them what they saw," suggested Jack.</p>
+
+<p>"That's what we will," assented Tom.</p>
+
+<p>But the airmen had nothing to report. They had ascended high in search
+of a hostile craft carrying a big gun, but had seen none.</p>
+
+<p>They had journeyed far over the German lines, hoping to discover the
+emplacement of the gun, if a long range cannon was being used. But they
+saw nothing.</p>
+
+<p>"Not even flashes of fire?" asked Tom.</p>
+
+<p>"Oh, yes, we saw those," an aviator said. "But there were so many of
+them, and in so many and such widely scattered places, that we could
+not tell which one to bomb. We did manage to hit some, though with what
+effect we could not tell."</p>
+
+<p>"Then the German gun is still a mystery," observed Tom.</p>
+
+<p>"It is. But we shall discover it soon. We will never rest until we do!"</p>
+
+<p>So more and new and different theories continued to be put forth
+regarding the big cannon, if such it was. Ordnance experts wrote
+articles, alike in London, Paris, and New York, explaining that it was
+possible for a cannon to be within the German lines and still send a
+shell into the French capital. But few believed that it was feasible.
+The general opinion was that the gun was of comparative short range, and
+was hidden much nearer Paris than the sixty or seventy-odd miles away,
+beyond which stretched the German line of trenches.</p>
+
+<p>Meanwhile Tom, though making careful inquiries, had learned nothing of
+his father. He did not feel it would be wise to cable back home, and ask
+what the news was there.</p>
+
+<p>"It might spoil dad's plans if I did that," said Tom to his chum, "and
+it would worry the folks in Bridgeton to know that I haven't yet seen
+him in France. No, I'll just have to wait."</p>
+
+<p>And wait Tom did, though there is no harder task in all the world.</p>
+
+<p>It was one morning, after a night bombardment on the part of the
+Germans, that Jack, who had been out for a morning paper, came rushing
+into the room where Tom was just awakening.</p>
+
+<p>"Great news, old man! Great!" cried Jack, waving the paper about his
+head.</p>
+
+<p>"You mean about a victory?" asked Tom.</p>
+
+<p>"No, not exactly, though it may lead to that. And it isn't any news
+about your father, I'm sorry to say. It's about the German gun. A 'dud'
+fell last night."</p>
+
+<p>"A 'dud'?" repeated Tom, hardly sensing what Jack said.</p>
+
+<p>"Yes, you know! A shell that didn't explode. Now they have a whole one
+to examine, and they can find out what sort of gun shot it. This paper
+tells all about it. Come on! Let's go for a look at the 'dud'!"</p>
+
+
+
+<hr style="width: 65%;" />
+<h2><a name="CHAPTER_XI" id="CHAPTER_XI"></a>CHAPTER XI</h2>
+
+<h3>A MONSTER CANNON</h3>
+
+
+<p>Tom, dressing hastily, read the account in the Paris paper of the fall,
+in an outlying section of the city, of one of the German shells that
+failed to explode. It was being examined by the military authorities, it
+was stated, with a view to finding out what sort of gun fired it, so
+that measures might be taken to blow up the piece or render it useless
+to the enemy.</p>
+
+<p>"That sounds good to me," said Tom, as they made a hasty breakfast.
+"This is getting down to a scientific basis. An unexploded shell ought
+to give 'em a line on the kind of gun that fired it."</p>
+
+<p>"The only trouble," said Jack, "is that the shell may go off when they
+are examining it."</p>
+
+<p>"Oh, trust the French ordnance experts not to let a thing like that
+happen," said Tom. "Now let's go to it."</p>
+
+<p>It was fortunate that Tom and Jack wore the uniforms that had so
+endeared them to France, or they might have had difficulty in gaining
+admittance to the bureau where the unexploded shell was under process
+of investigation. But when they first applied, their request was
+referred to a grizzled veteran who smiled kindly at them, patted them on
+the shoulders, called them the saviors of France, and ushered them into
+the ordnance department, where special deputies were in conference.</p>
+
+<p>"Yes, we have one of the Boche shells," said an officer, who spoke
+English fluently, for which Tom and Jack were glad. They could speak and
+understand French, but in a case like this, where they wanted a detailed
+and scientific explanation, their own tongue would better serve them.</p>
+
+<p>"And can you tell from what sort of gun it comes?" asked Tom.</p>
+
+<p>"It was fired from a monster cannon," was the answer. "That is a cannon
+not so much a monster in bore, as in length and in its power to impel a
+missile nearly eighty miles."</p>
+
+<p>"Can it be done?" asked Jack.</p>
+
+<p>"It has been done!" exclaimed Major de Trouville, the officer who was
+detailed to talk to the boys "It has been done. That is the gun that has
+been bombarding Paris."</p>
+
+<p>"But, from a military standpoint," began Tom, "is it&mdash;"</p>
+
+<p>"It is utterly useless," was the quick answer. "Come, I will show you
+the shell."</p>
+
+<p>He led them to an apartment set aside for the testing of explosives and
+working out ordnance problems, and there on a table, around which sat
+many prominent French officials, was the German shell&mdash;the "dud," as
+Jack had called it.</p>
+
+<p>"The charge has been drawn," explained Major de Trouville, "so there is
+no danger. And we have determined that the manner in which shots reach
+Paris from a distance of from seventy to eighty miles is by the use of a
+sub-calibre missile."</p>
+
+<p>"A sub-calibre?" murmured Tom.</p>
+
+<p>"Yes. You know, in general, that the more powder you use, and the larger
+the surface of the missile which receives it, the greater distance it
+can be thrown, providing your angle of elevation is proper."</p>
+
+<p>The boys understood this much, in theory at least.</p>
+
+<p>"Well," went on the major, "while that is true, there is a limit to it.
+That is to say you could go on using powder up to hundreds of pounds in
+your cannon, but when you get to a certain point you have to so increase
+the length of the gun, and the size of the breech to make it withstand
+the terrific pressure of gases, that it is impracticable to go any
+further. So, also, in the case of the shell. If you make it too large,
+so as to get a big surface area for the gases of the burning powder to
+act upon, you get your shell too heavy to handle.</p>
+
+<p>"Now of course the lighter a missile is, the farther it will go, in
+comparison to a heavy one with the same force behind it. But you can not
+get lightness and sufficient resistance to pressure without size, and
+here is where the sub-calibre comes in."</p>
+
+<p>"In other words the Germans have been firing a shell within a shell,"
+broke in another officer.</p>
+
+<p>"Exactly," said Major de Trouville. "The Germans have evolved a big gun,
+that is big as regards length, to enable the missile they fire from it
+to gain enough impulse from the powder. But the missile would be too
+large to travel all the way to Paris. So they use two. The inner one is
+the one that really gets here and explodes."</p>
+
+<p>"What becomes of the outer?" asked Jack.</p>
+
+<p>"It is a sort of container, or collar, and falls off soon after the
+shell leaves the big gun. If you will imagine a sort of bomb shell being
+enclosed in an iron case, the whole being put in a gun and fired, you
+will better get the idea. The outer case is made in two or more pieces,
+and soon after it is shot out it falls away, leaving the smaller missile
+to travel on. But here is where the cunning of the invention comes in.
+The smaller missile has all the impetus given the larger one, but
+without its weight. In consequence it can travel through eighty miles of
+atmosphere, finally reaching Paris, where it explodes."</p>
+
+<p>"Wonderful!" exclaimed Jack.</p>
+
+<p>"And yet it is merely the adaptation of an old theory," went on the
+major. "We have known of the sub-calibre theory for years, but it is not
+practicable. So we did not try it. The cost is too great for the amount
+of military damage done. And this shell, as you will see, is composed of
+two parts, each with a separate explosive chamber, each containing, as
+we discovered, a different sort of explosive. In this way if one did not
+go off, the other would, and so set off the one that failed. It is very
+clever, but we shall be more clever."</p>
+
+<p>"That's right!" chimed in a chorus of fellow officers.</p>
+
+<p>"We'll find the gun and destroy it&mdash;or all of them if they have more
+than one, as they probably have," went on the major.</p>
+
+<p>He showed the boys where the shell had chambers for the time fuses to
+work, much as in a shrapnel shell, which can be set to go off so many
+minutes or so many seconds after it reaches its objective point.</p>
+
+<p>"And so the great question is settled by the failure of this shell to
+explode," went on the major. "As soon as we saw it, and noted the
+absence of the rifling groove marks, we knew it must have been a
+sub-calibre matter. The rest was easy to figure out.</p>
+
+<p>"Some of us thought there might be a big airship, stationed high above
+the clouds, dropping bombs. Others inclined to the theory of a double
+shell; that is, after one had been fired from the cannon it would
+travel, say, half way and then explode a charge which would impel
+another shell toward Paris. A sort of cannon within a cannon, so to
+speak. But this is not so. Nor did the theory of a shell with a sort of
+propeller device, like that of a torpedo, prove to be right. It is much
+simpler&mdash;just sub-calibre work."</p>
+
+<p>"And what is going to be done about it?" asked Tom. "I mean how can the
+monster cannon be silenced?"</p>
+
+<p>"Ah, that is a matter we are taking up now," was the answer of Major de
+Trouville. "I fancy we shall have to call on you boys for a solution of
+that problem."</p>
+
+<p>"On us?" exclaimed Jack.</p>
+
+<p>"Well, I mean on the aircraft service. It will be their task to search
+out this great German cannon for us, to enable our gunners to destroy
+it. Or it may be that it will have to be bombed from an aeroplane."</p>
+
+<p>"That's the task I'd like all right!" cried Tom, with shining eyes.</p>
+
+<p>"Same here!" echoed Jack. "Do you suppose we'll get a chance?" he asked
+eagerly.</p>
+
+<p>"You may," was the reply. "It may take all the resources of our airmen
+to destroy this terror of the Germans. But it will be done, never fear!"</p>
+
+<p>"<i>Vive la France!</i>" cried his companions, and there was a cheer in which
+Tom and Jack joined.</p>
+
+<p>And so a part of the secret was discovered. It was a monster cannon that
+was devastating Paris. A great gun, the construction of which could only
+be guessed at. But it must be destroyed! That was certain!</p>
+
+
+
+<hr style="width: 65%;" />
+<h2><a name="CHAPTER_XII" id="CHAPTER_XII"></a>CHAPTER XII</h2>
+
+<h3>FOR PERILOUS SERVICE</h3>
+
+
+<p>Tom and Jack spent some little time looking at the strange German shell.
+It was of peculiar construction, arranged so that the two explosive
+charges would detonate together or separately, according as the
+mechanism was set.</p>
+
+<p>But in this case it had failed to work, and the shell, falling in a bed
+of soft sand, near some new buildings which were going up, had not been
+fired by concussion, as might have happened.</p>
+
+<p>"And it was just French luck that it didn't go off," observed Jack.</p>
+
+<p>"That's right," agreed Tom. "If they hadn't had this whole shell to
+examine they wouldn't know about the big gun."</p>
+
+<p>So all the theories, fantastic enough some of them, about great airships
+hovering over the beautiful city, and dropping bombs from a great
+height, were practically disproved.</p>
+
+<p>"Well, now that you have decided it is a big German gun, the next
+question is, where is it and what are you going to do about it?"
+observed Tom, for he and Jack had been made so much of by the French
+officers that they felt quite at home, so to speak.</p>
+
+<p>"Ah, messieurs, that <i>is</i> the question," declared Major de Trouville.
+"First to find the gun, and then to destroy it. The first we can do with
+some degree of accuracy."</p>
+
+<p>"How?" asked Tom.</p>
+
+<p>The major went to a large map hanging on the wall of the room. It showed
+the country around Paris and the various lines as they had been moved to
+and fro along the Western front, according as the Germans advanced or
+retreated.</p>
+
+<p>"You will observe," said the major, "that by describing an arc, with
+Paris as the center of the circle, and a radius of about seventy-five
+miles, you will include a small sector of the German trenches. Roughly
+speaking this arc will extend from about Hamegicourt to Condé, both
+within the German lines, I am sorry to say. Now then, somewhere in this
+arc, or perhaps back of it, the German gun is placed. Anywhere else
+where it would be possible for such a monster engine of war to be
+erected, would bring it too close to our batteries.</p>
+
+<p>"So that gives us the comparative location of the gun," went on the
+French officer. "But the next question is not so easy to settle&mdash;how to
+get rid of it. As I said, I think we shall have to depend on you
+airmen."</p>
+
+<p>"Well, we're for the job!" exclaimed Tom.</p>
+
+<p>"I know you are. And it may fall to you, or to your friends. I will talk
+of that later."</p>
+
+<p>"Have you been able to get any idea of the kind of gun it is, or why it
+fires at fifteen minute intervals?" asked Jack.</p>
+
+<p>"We have been able to get no really reliable information save that which
+we deduce by our observations of this shell and from what we know of the
+location of our own and the German lines," the Major went on. "Up to now
+our airmen have not been able to penetrate far enough without being
+attacked, and such few as did get well over toward the Rhine could make
+out nothing. I have no doubt the gun is well camouflaged."</p>
+
+<p>"And is it true that it doesn't fire at night because the Germans are
+afraid the flashes will be seen?" asked Tom.</p>
+
+<p>"That may have been the reason at first, but they have fired at night,
+of late, so they must have some way of concealing the flashes, or
+perhaps setting off other flashes at the same time so as to confuse our
+scouts."</p>
+
+<p>"It's going to be some job," murmured Jack.</p>
+
+<p>"You said something," agreed his chum.</p>
+
+<p>They remained talking a little longer, and some of the officers who
+knew the reason for Tom's visit to Paris, expressed regret that he had
+no information as yet about his father.</p>
+
+<p>"But take heart," one told him. "He is not dead, or we should have heard
+of it. Of course he may have fallen into the hands of the Germans, and
+then we would not know for some time."</p>
+
+<p>"He may have been caught," agreed Tom. "While Tuessig is out of the game
+on account of his injuries, he may be able to direct Potzfeldt, and that
+scoundrel would have good reason for trying to get revenge on us."</p>
+
+<p>"Ah, yes, I heard about your rescue of the young lady and her mother,"
+said the major. "It was a brave deed."</p>
+
+<p>"Oh, any one could have done it," said Tom, modestly.</p>
+
+<p>"And have you seen them since they came to Paris?" the major proceeded.</p>
+
+<p>"No, but I wish we could find them!" burst out Jack, and then he blushed
+at his impetuosity, while Tom murmured something about "Bessie," and
+Jack promptly told him to hold his tongue.</p>
+
+<p>"Perhaps you may meet them sooner than you expect," went on the French
+officer.</p>
+
+<p>"Now I wonder what he could have meant by that?" asked Jack, as he and
+his chum went out, after a final look at the German shell. "Does he
+know where they are?"</p>
+
+<p>"It wouldn't be surprising, seeing that Mrs. Gleason is probably in Red
+Cross work, and Bessie may be helping her. We should have looked them up
+before," went on Tom. "But what with searching for my father, and the
+excitement about the bombardment, I really forgot all about them."</p>
+
+<p>Jack did not say whether he had or not, the chances being that he had,
+more than once, thought of Bessie Gleason.</p>
+
+<p>During the next two days the monster cannon continued to shoot shells at
+intervals into Paris. Some did considerable damage, as any shell would
+do in a great city, and many unfortunates were killed. But there was no
+reign of terror such as, undoubtedly, the Boches hoped to create. Paris
+remained calm, and there were even jokes made about the cannon. It was
+called a "Bertha" and other names, the former referring to Bertha Krupp,
+one of the owners of the great German ordnance works.</p>
+
+<p>Word was given out that the French gunners on the front were trying to
+reach the big gun with their missiles. But as they were firing blindly
+it could not be said what havoc had been wrought.</p>
+
+<p>"But, sooner or later, we'll get the range, and get within striking
+distance," said one of the French officers. "Then we'll show them a
+trick or two."</p>
+
+<p>"Have the aviators done anything toward trying to find the gun?" asked
+Tom. "I mean anything more."</p>
+
+<p>"We are perfecting our plans for the flying corps," was the answer.
+"Perhaps you shall know more in a few days."</p>
+
+<p>"Well, I hope we'll be here when the fun begins," said Tom, grimly.
+"We've got another extension of leave, and I'm going to ask the police
+now, to co-operate with the military in seeking my father."</p>
+
+<p>"I think that will be a wise plan. We will give you all the help we
+can."</p>
+
+<p>But the quest for Mr. Raymond seemed a hopeless one, and as no
+confirmation could be had of his death or injury, the idea gradually
+became fixed in the minds of Tom and Jack that he had been made a German
+prisoner.</p>
+
+<p>"If that is so, and I can get any trace of him, I'll go over the Rhine
+to get him back," snapped Tom.</p>
+
+<p>"And I'll go with you!" declared his chum.</p>
+
+<p>It was a few days after they had inspected the German "dud," and the
+boys were wondering what new developments might take place, the shelling
+of Paris meanwhile continuing at intervals, that one evening the boys
+were visited in their lodgings by Major de Trouville.</p>
+
+<p>"Is there any news?" eagerly asked Tom, for he guessed that the French
+officer would not be paying a merely social call. Those were the
+strenuous days when such things had passed.</p>
+
+<p>"Well, yes, news of a sort," was the answer. "But what I came to find
+out was whether you were so taken with these lodgings that you could not
+be induced to move."</p>
+
+<p>"To move!" exclaimed Jack.</p>
+
+<p>"Yes. Have you found anything unhealthful here?"</p>
+
+<p>"Why, no," replied Tom, wonderingly. "We like it here. The landlord
+couldn't be nicer, and we're in a good location."</p>
+
+<p>"Nevertheless, I fear I shall have to ask you to change your quarters,"
+went on the major, and by the quizzical smile on his face the boys
+guessed that there was something in the wind.</p>
+
+<p>"Let me ask you another question," went on the French officer. "Have you
+been annoyed since you have been here?"</p>
+
+<p>"Annoyed? How?" inquired Tom.</p>
+
+<p>"By unwelcome visitors, or by strangers."</p>
+
+<p>The boys thought for a moment.</p>
+
+<p>"There's one chap who lives in the same building here, whom we've seen
+on our staircase several times," said Jack, slowly. "Once I saw him
+pause at our door with a key, as though he were going to enter, but he
+heard me coming, and, muttering that he had taken too much wine and was
+a bit hazy in his memory, he went on upstairs."</p>
+
+<p>"I thought as much," the major said. "Was the man you speak of familiar
+to you?"</p>
+
+<p>"No, I can't say that he was," replied Jack, and Tom nodded his
+acquiescence. "I never saw him before."</p>
+
+<p>"Oh, yes you have," and the major smiled.</p>
+
+<p>"I have? Where?"</p>
+
+<p>"On the train, coming into Paris."</p>
+
+<p>"You mean the German spy?" cried Jack.</p>
+
+<p>"The same," answered the Frenchman. "That's just what he is, and he is
+spying on you. Now, in view of what is going to happen, we don't want
+that to go on. So I have come to ask you to change your lodgings, and I
+think I can take you to one that will be most agreeable to you both."</p>
+
+<p>"But what does all this mean?" asked Tom. "Is there&mdash;&mdash;"</p>
+
+<p>"There is 'something doing' as you say so picturesquely in the United
+States," interrupted the major. "I have come to tell you that you are to
+undertake a most perilous mission!"</p>
+
+
+
+<hr style="width: 65%;" />
+<h2><a name="CHAPTER_XIII" id="CHAPTER_XIII"></a>CHAPTER XIII</h2>
+
+<h3>THE SPY</h3>
+
+
+<p>Tom Raymond and Jack Parmly looked first at one another and then at the
+major. He had been smiling at their wonderment, but he was now serious,
+and regarded them gravely.</p>
+
+<p>"Do you mean we have to do something to help catch this spy?" asked Tom.</p>
+
+<p>"I'd like a hand in that!" exclaimed Jack. "I saw him first&mdash;he's my
+meat!"</p>
+
+<p>"Well, get him if you can, boys," said the Frenchman. "But I did not
+come here to talk so much about him as about yourselves. The spy is a
+danger and a menace, but we know him and if he goes too far we can put
+out our hands and drag him back.</p>
+
+<p>"No, what I referred to is more dangerous than merely trying to catch a
+spy at his sneaking work. I will tell you." The major suddenly left his
+seat near the window of the boy's room, and quickly opened the door
+leading to the hall. The passage was empty.</p>
+
+<p>"I rather thought there might be an eavesdropper," the major explained.
+"I was followed here, though I don't believe the spies know my mission.
+However, it is best to be careful. With your permission I'll pull down
+the shade. There may be spies stationed across the street who, with
+powerful glasses, might look through the window and gather something of
+what we say by reading our lips. It has been done."</p>
+
+<p>"The Germans don't leave much untried," commented Tom. "But what is it
+you want us to do, if it isn't trying to trail the spy?"</p>
+
+<p>The major motioned them to draw closer to him, and then, leaving the
+door into the hall open, so that he could note the approach of any one,
+he whispered:</p>
+
+<p>"You are to be two members of a picked company of air scouts who are to
+go out, discover the big German gun, and destroy it!"</p>
+
+<p>"Whew!" whistled Tom, after a moment of thought during which he and Jack
+exchanged quick glances.</p>
+
+<p>"Well?" asked the officer. "How does that strike you? I believe that is
+another of your captivating terms?"</p>
+
+<p>"It's all to the good!" exclaimed Jack. "What say, Tom? We'll take that
+on, won't we?"</p>
+
+<p>"Well, I should say!" was the enthusiastic rejoinder. "When do we start
+to&mdash;"</p>
+
+<p>"Hush!" cautioned the major. "Not so loud. Though we have taken every
+precaution, there may be spies unseen by us. We had better talk no more
+about it here."</p>
+
+<p>"Then let's go to our new lodgings, if we are to move," suggested Tom.
+"Will it be safe to talk there?"</p>
+
+<p>"I think so," the major said. "At least you will be among friends. Not
+that your landlord here is not a true Frenchman; but he can not control
+the actions of those to whom he lets lodgings. You will be better where
+you are going. Then you accept the mission?" he asked in another
+whisper.</p>
+
+<p>"Sure thing!" answered Tom, while Jack nodded his assent. "The sooner
+the quicker!"</p>
+
+<p>"I do not quite get that," the major confessed with a smile. "But I
+think I gather your meaning. Now if you will proceed to this address,"
+and he handed Tom a small slip of paper, "you will find a comfortable
+lodging, and you will be among friends."</p>
+
+<p>"How soon can we start on&mdash;on this mission?" asked Tom.</p>
+
+<p>"It will be better not to refer to it directly," the officer said. "Talk
+as little about it as you can. But you shall go as soon as the
+arrangements can be made. You will be notified."</p>
+
+<p>"And what about seeing our friends&mdash;Mrs. Gleason?" asked Jack.</p>
+
+<p>"Are you sure its <i>Mrs.</i>. Gleason you want to see?" inquired Tom.</p>
+
+<p>"Oh, cut it out!" advised Jack with a blush.</p>
+
+<p>"You may see them soon now," the major told him with a smile. "And I
+hope you'll soon have good news of your father," he added to Tom.</p>
+
+<p>"I hope so, too. The suspense is telling on me."</p>
+
+<p>"I should think it would. Now don't leave this bit of paper about with
+the address of your new lodgings on. Better commit it to memory, and
+then destroy the sheet. We want, if possible, to prevent the spy from
+knowing where you have gone. I will call a taxicab for you. You can be
+packed soon, I suppose?" he questioned.</p>
+
+<p>"Within a half hour," answered Jack. "But say, won't that spy be on the
+watch, and won't he learn from the taxicab driver where we have gone?"</p>
+
+<p>"Not from <i>this</i> taxicab driver," was the smiling answer. "He is one of
+our best secret service men. But treat him as you would an ordinary
+chauffeur. You may even give him a tip, and he will not be offended,"
+and once more the major smiled.</p>
+
+<p>Tom and Jack, having made sure they remembered the address given them,
+destroyed the paper, and then proceeded to get ready to move. Meanwhile
+Major de Trouville took his departure, promising to keep in
+communication with the Air Service boys.</p>
+
+<p>Punctual to the half hour a taxicab appeared at the door. The boys
+obeyed the instructions they had received, and looked out to make sure
+the spy was not on hand. If he was, he was well concealed, for they did
+not see him.</p>
+
+<p>"Though I suppose he's somewhere around," said Jack.</p>
+
+<p>"Well, maybe we can fool him," suggested Tom. "We're going quite on the
+other side of Paris."</p>
+
+<p>They made sure that, as far as could be told by observation, there was
+no one resembling the spy around the place or in the street in front,
+and then got into the cab with their baggage. The chauffeur seemed not
+to know them, but Tom thought there was just the slightest wink of one
+eye, as though to indicate that the game was going well.</p>
+
+<p>Their cab was driven out along the Boulevard Ragenta, past the Gare du
+Nord, and across the Boulevard de Rochechquart to a small street running
+off the Rue Ramey, and there the cab stopped in front of a small but
+neat-looking house.</p>
+
+<p>"Quiet enough neighborhood," remarked Jack, as they got down, and Tom
+tipped the cabman for the benefit of any spies who might be looking.</p>
+
+<p>"Yes, I guess we can get some sleep here, if the big gun doesn't keep us
+awake," agreed Tom.</p>
+
+<p>On the way they had passed several places where the havoc of the
+"Bertha" was noticeable.</p>
+
+<p>Tom and Jack seemed to be expected, for the porter, who came down to get
+their bags, did not seem at all surprised to see them. He bade them
+follow him, and a little later, the cab having chugged off, the boys
+were settled in a pleasant room, a smiling landlady coming in to see if
+they wanted anything, and to tell them they could have meals with her at
+certain hours, or they might dine out as they pleased.</p>
+
+<p>"Your friends will be here shortly," she added.</p>
+
+<p>"Our friends?" questioned Tom.</p>
+
+<p>"Yes," with a nod and a smile. "I was told to say they would be here
+shortly after you arrived."</p>
+
+<p>"Oh, I guess she means the major and some of the officers will come to
+see how we are situated, and to tell us more about&mdash;the big stunt," said
+Tom in English to his chum, assuming that "big stunt" would sufficiently
+disguise to any listening spies, if such there were, the real object
+that lay before them.</p>
+
+<p>"I suppose that's who she means," agreed Jack, as the landlady, who gave
+her name as Madame Reboux, withdrew.</p>
+
+<p>The boys were busy unpacking their few belongings, for they had not
+brought much to Paris, not intending to stay long, when they heard
+voices in the hall outside their room. And at the tones of a certain
+voice Tom and Jack started and looked at one another.</p>
+
+<p>"Listen!" exclaimed Tom.</p>
+
+<p>"If I wasn't afraid you'd say I was dreaming, I'd say I knew that
+voice!" murmured Jack.</p>
+
+<p>"I'd say the same," added Tom.</p>
+
+<p>"Who would you say it was?" his chum challenged.</p>
+
+<p>"Well, for a starter&mdash;"</p>
+
+<p>He paused, for the voice sounded more plainly now, and it said:</p>
+
+<p>"Yes, this is the right place, Mother. Oh, do you think the boys are
+here yet?"</p>
+
+<p>"It surely will be a pleasure to meet them again," said another voice,
+evidently that of a woman, the other having been a girl's.</p>
+
+<p>"I hope they won't have forgotten us," the girl went on, and at that
+Jack could no longer keep quiet. He rushed to the door, opened it, and
+cried:</p>
+
+<p>"Bessie! Is that you?"</p>
+
+<p>"Oh, it's Jack! Mother, here's Jack!" cried the girl, and she and her
+mother were soon shaking hands with Tom and Jack.</p>
+
+<p>"So, you two were the friends we were soon to see!" exclaimed Tom, as he
+placed chairs for Mrs. Gleason and her daughter. Or, to be exact, Tom
+placed a chair for the mother, while Jack got one for Bessie.</p>
+
+<p>"Yes, we were told you would be here," said Bessie's mother. "We did not
+know you were in Paris until we received word that it would be better
+for us to change our lodging and come here."</p>
+
+<p>"The same word we received," said Jack. "Say, it's working out mighty
+queer, isn't it, Tom?"</p>
+
+<p>"Yes, but very satisfactorily, I should say. Things couldn't be nicer.
+How have you been?" he asked, for he had not seen the girl nor her
+mother since the sensational rescue from the perfidious Carl Potzfeldt.</p>
+
+<p>"Very well indeed," answered Mrs. Gleason. "Both Bessie and I have been
+doing Red Cross work. But isn't that great German gun terrible? Oh, how
+it has killed and maimed the poor women and children! The Huns are
+fiends!"</p>
+
+<p>"I quite agree with you," said Tom, Jack meanwhile talking to Bessie.
+"But it isn't doing them the military good they thought it would, and,
+if all goes well, it may not very long do them any service at all."</p>
+
+<p>"You mean&mdash;" began Mrs. Gleason.</p>
+
+<p>But just then Bessie, who had arisen to go to the window to view the
+street, turned back with a start, and grasped Jack's hand.</p>
+
+<p>"Look! Look!" she whispered, and through the curtains she pointed to a
+man on the opposite side of the way.</p>
+
+<p>"Do you know him?" asked Jack.</p>
+
+<p>"Know him? Yes, to my sorrow."</p>
+
+<p>"Who is it?" asked Tom.</p>
+
+<p>"The spy!" exclaimed Jack. "The man we saw in the train, and the same
+fellow who tried to get into our lodgings. In spite of our precautions
+he has found out where we are."</p>
+
+<p>"I'm not so sure of that," said Tom. "He may not be here for any
+particular purpose. But do you know him too, Bessie?"</p>
+
+<p>"Yes," the girl answered. "He was in the château where mother and I were
+held prisoners by Potzfeldt. He is a tool in the pay of that spy, and a
+spy himself!"</p>
+
+<p>"Then we ought to do something!" exclaimed Jack, and he started to rush
+from the room.</p>
+
+
+
+<hr style="width: 65%;" />
+<h2><a name="CHAPTER_XIV" id="CHAPTER_XIV"></a>CHAPTER XIV</h2>
+
+<h3>WITH COMRADES AGAIN</h3>
+
+
+<p>"Hold on! Wait a minute!" exclaimed Tom, as he caught hold of his chum.
+"Where are you going?"</p>
+
+<p>"Out to give warning to a policeman or to some army officer about that
+spy!" exclaimed Jack. "We know him to be such, and now, with Bessie's
+word that he was with Potzfeldt, it's enough to cause his arrest."</p>
+
+<p>"Yes, maybe it is," agreed Tom, who was a bit more cautious than his
+impetuous chum. "But if we do that we may spoil the plans of Major de
+Trouville. Better let matters take their course, Jack. That spy may not
+know we are here, and again, he may. But if he doesn't, rushing out now
+would be sure to give the secret away. As it is, there is a chance we
+may keep it."</p>
+
+<p>Jack, caught midway in his impetuous rush from the room, stood
+reflectively. What Tom had said to him appeared to make an impression.
+Then Bessie added her words of advice.</p>
+
+<p>"Yes, Jack," she said, "I think it would be rather rash to go out now
+and confront that man, or start a chase after him. I know I'm not as
+experienced as you two famous birdmen," she went on with a smile, "but
+I've been through some terrible experiences, as almost every girl has in
+this war zone, and I can do more thinking than I used to. Don't you
+think it would be wise to wait, Mother?"</p>
+
+<p>"Yes, Bessie," answered Mrs. Gleason, "I do. Our good friends in the
+military service who told us to come here, must have had some object.
+Perhaps it was connected with this same man who was so unkind to us in
+the château, and who was certainly a tool of that man I trusted once,
+but never will again&mdash;Carl Potzfeldt!" and she shuddered as she thought
+of what she had gone through.</p>
+
+<p>"Let him go," she said to Jack. "Perhaps it is just a coincidence that
+he is passing just as we arrive. Our departure from our last lodgings
+was made secretly."</p>
+
+<p>"So was ours," said Tom. "And yet I don't see how that spy found us so
+soon."</p>
+
+<p>"It is that which makes me think it is accidental," observed Mrs.
+Gleason. "It would be very unwise now to go out, I think."</p>
+
+<p>"All right, then I'll stay in," said Jack with a smile. "Especially as I
+have such good company. Tell me," he went on, "are you and your mother
+going to board here?" he asked Bessie.</p>
+
+<p>"Yes," answered Mrs. Gleason. "And though we were told we would meet
+friends here we could not guess it would be you brave boys."</p>
+
+<p>"Spare my blushes!" laughed Tom.</p>
+
+<p>"Same here," added Jack.</p>
+
+<p>"But what brings you to Paris?" asked Bessie. "I thought you boys were
+engaging in combats above the clouds."</p>
+
+<p>"We have been fighting, though not during the last two weeks," said Tom.
+"I had word that my father had come over here, but he never communicated
+with us, and we came to Paris to look him up. So far we haven't
+succeeded in finding him," and he gave the details of the visit of
+himself and his chum to the capital, telling of their first experience
+during the firing of the big gun.</p>
+
+<p>Bessie and Jack, who seemed to have much to say to one another, peered
+from behind the curtains out of the window now and then, and Jack at
+last reported that the spy had passed on, after stopping, apparently, to
+purchase some fruit at a stand on the street.</p>
+
+<p>"I don't believe he knew we were here," said Bessie.</p>
+
+<p>"Well, it won't do to take any chances," observed Tom. "However, we were
+not told to remain under cover, so I suppose we can go out when we
+like."</p>
+
+<p>"Better wait until we get some word from the major," suggested Jack, who
+was getting some of his chum's caution.</p>
+
+<p>All decided this was best, and the boys spent the rest of the afternoon
+in getting their room to rights, Mrs. Gleason and Bessie doing the same
+in their apartment. Mrs. Gleason had temporarily been relieved from Red
+Cross work to recuperate, she said, as she had been under a great
+strain.</p>
+
+<p>Toward evening Major de Trouville, or "Trouville," as he democratically
+liked to be called, arrived, and when told of the sight in the street of
+the spy, who turned out to be the same man who was one of the captors of
+Bessie and her mother, the officer said:</p>
+
+<p>"I am not surprised. In fact I rather looked for that, and it is one
+reason why I wanted to get you four together so you could see the man at
+the same time.</p>
+
+<p>"There is now no doubt as to his intentions, and the fact that he was
+here so soon after you arrived proves that there is a 'leak' somewhere.
+We suspected as much, and I think I know where it is. It is good
+information to have. Well, boys, did I surprise you?" he asked, smiling.</p>
+
+<p>"You did, indeed, but it was a pleasant surprise," said Jack.</p>
+
+<p>"But when are we going to be allowed to do something to silence that
+monster cannon?" asked Tom. "It's pleasant to be here, but we are not
+forgetting there is work to do."</p>
+
+<p>"Nor would I have you forget," said the major. "A number of persons were
+killed to-day by fire from the long-range gun. We believe, now, that
+there are two or three of them, as the shots come at closer intervals.
+It is imperative that something be done, and so I have brought you
+orders."</p>
+
+<p>"Good!" cried Jack.</p>
+
+<p>"That sounds like business!" commented Tom.</p>
+
+<p>"In regard to your father," went on the major, addressing Jack's chum,
+"we will be on the watch for him, or any news of him, and, no matter
+where you are, unless you are captured by the Germans, you shall be
+informed as soon as possible."</p>
+
+<p>"Is there any chance of being made prisoners?" asked Jack, and it might
+be noted that he did not use the word "danger."</p>
+
+<p>"There is always that chance for an airman," replied the major. "But
+when I add that it may be possible that one or both of you will take a
+flight over the Rhine, you can judge, with the hold Germany has on
+French possessions, what the danger is."</p>
+
+<p>"Over the Rhine!" exclaimed Tom. "Why, that's a flight of two or three
+hundred miles from Paris."</p>
+
+<p>"Yes, but with the new type of Italian plane which you may use, it is
+not impossible in a single flight," said the major. "However, we will
+talk of that later. Just now I have come to tell you that you are to
+rejoin your comrades at the Lafayette Escadrille for a time. There
+arrangements will be made for the perilous venture I spoke of&mdash;the
+silencing of the big guns that are bombarding Paris. I wish you all
+success, young gentlemen."</p>
+
+<p>"Thanks," murmured Jack.</p>
+
+<p>"We consider it an honor to be picked for such duty," added Tom. "Are
+any others going to be in the game?"</p>
+
+<p>"Oh, yes. We shall need a picked corps of the best airmen we have,
+French and Americans, and it will be no easy matter then. The Germans
+have probably been planning this for a long time, and they, no doubt,
+have taken every possible precaution against surprise or failure. But
+with the help of you brave Americans we shall win!"</p>
+
+<p>"That's right!" chimed in Bessie. "Oh, how I wish I were a man!" and she
+looked enviously at Jack and Tom.</p>
+
+<p>The major gave Bessie and her mother some instructions in regard to
+their actions should the spy come back, and then told Tom and Jack to
+prepare to leave Paris the next night.</p>
+
+<p>"Report to your former camp," he said, "and there you will find further
+instructions waiting for you."</p>
+
+<p>"Well, then as we have to-night, our last one free, let's go to some
+entertainment," suggested Tom to Bessie and her mother. "We can have
+supper afterward&mdash;not much of a celebration, for these are war times and
+it won't do to rejoice too much. But we ought to commemorate this
+meeting somehow."</p>
+
+<p>"That's right!" agreed Jack.</p>
+
+<p>So they went to a little play and had supper afterward in a quiet
+restaurant. That is, it was quiet until a sudden explosion a few blocks
+away announced the arrival of another German shell from the big gun, and
+then there was excitement enough.</p>
+
+<p>Fortunately, however, the shots did little beyond material damage, no
+one being killed. At the same time, however, there appeared some German
+planes over Paris, doubtless to observe the effect of the dropping of
+the long-distance shells, and naturally the French airmen went up to
+give them combat.</p>
+
+<p>The great searchlights began to play, picking out the hostile craft, and
+making them targets for the machine guns of the intrepid Frenchmen, and
+more than one Boche never got back over his lines again, while several
+Frenchmen found heroes' graves on the soil they had died to defend.</p>
+
+<p>"Oh, if we were only up there helping," said Tom, as he and his friends
+watched.</p>
+
+<p>"We shall be there very soon," murmured Jack. "And it can't be any too
+soon for me."</p>
+
+<p>The tide of battle turned in favor of the French, the Hun planes
+withdrawing as the fire got too hot for them. And soon after that the
+long-range gun ceased firing.</p>
+
+<p>It was rather a "pull" for Tom and Jack to say good-bye to Bessie and
+her mother in Paris, but they knew they had to do their duty. Nor would
+Mrs. Gleason and her daughter have kept the boys back for the world.
+They realized that the Air Service boys were helping to make the world
+safe for democracy, as they themselves were doing in their way.</p>
+
+<p>And so Tom and Jack, their mission to Paris, which was the discovery of
+Mr. Raymond, having failed, went back to the hangars, there to be
+welcomed by their comrades in arms.</p>
+
+<p>They arrived one morning, just after some planes from a bombing
+expedition over the German lines returned.</p>
+
+<p>"What luck?" asked Tom of a pilot with whom he had often flown.</p>
+
+<p>"The best, as regards the damage we did," was the answer. "We blew up
+several ammunition dumps, and put one railroad center out of business
+for a time. But Louis didn't come back," and the man turned aside for a
+moment.</p>
+
+<p>"You mean your brother?" asked Jack, softly.</p>
+
+<p>"Yes."</p>
+
+<p>"Perhaps he is only captured," suggested Tom.</p>
+
+<p>"No, his machine caught fire. They got his petrol tank. It's all up with
+him and La Garde. But we had our revenge. We sprayed the machine that
+got them until there was nothing left of it. And I'm going out again
+to-day in a Nieuport. They'll pay a price for Louis!"</p>
+
+
+
+<hr style="width: 65%;" />
+<h2><a name="CHAPTER_XV" id="CHAPTER_XV"></a>CHAPTER XV</h2>
+
+<h3>THE PICKED SQUADRON</h3>
+
+
+<p>"All ready, Jack?"</p>
+
+<p>"Just a moment, Tom. I want to go over my struts and wires to make sure
+everything is taut. I don't want any accidents."</p>
+
+<p>"That's right. Got plenty of ammunition drums?"</p>
+
+<p>"All I can carry. I've got some tracer bullets, too."</p>
+
+<p>"That's good. Glad you reminded me of them. I must put in a stock. The
+last time I went up I wasted a drum before I got my man."</p>
+
+<p>Tracer bullets for aircraft guns, it might be observed, are balls of
+fire which enable the pilot to see the course his machine gun bullets
+are taking, so he may correct his fire.</p>
+
+<p>"Well, how about you now?" asked Tom, as he added these useful supplies
+to his ammunition.</p>
+
+<p>"I guess we're ready to start," replied Jack.</p>
+
+<p>They climbed into their machines, each pilot using a single-seat,
+swift-flying craft, equipped with a Lewis machine gun. The squadron was
+going out on patrol duty, and each pilot was to observe what he could
+behind the German lines, and come back to report&mdash;that is if he did not
+happen, as was too often the case, to be bagged by a German flier. The
+small, swift machines did not carry the wireless outfit, and no reports
+could be sent back to headquarters save those the pilot himself came in
+with.</p>
+
+<p>There was a rattle and a roar as the motors of the ten machines started,
+and then over the ground they went, "taxi fashion," to get the necessary
+speed to rise into the air. A moment later all went aloft, and were
+headed toward the German lines.</p>
+
+<p>Tom and Jack kept as close together as was safe, but it is dangerous for
+two aeroplanes to approach too closely. If they do, and are not under
+good control, there may be a suction created that will cause a
+collision.</p>
+
+<p>"Well, I hope I get one to-day," thought Tom, as he manipulated his "joy
+stick," so as to send his plane up on a sharp slant. "I want to make
+good, and then I'll have so much better chance to get after that German
+gun." And the same thought was in Jack's mind.</p>
+
+<p>The squadron was to remain aloft on a two-hour patrol, that is unless
+something should occur to make it advisable to remain up longer. The
+keen eyes of Tom and Jack, as well as those of their companions of the
+air, were searching for signs of the Hun planes. As yet none were in
+sight, but it would not be long before they would come out to give
+battle.</p>
+
+<p>Whatever else may justly be said about the Germans, their airmen are no
+cowards, and, when conditions are favorable, they seldom decline a
+chance to combat above the clouds, or lower down. So it could easily be
+guessed that when Tom, Jack and the others found themselves over the
+German lines that the Boches would be out in force.</p>
+
+<p>Somewhat off to the left Tom caught sight of a captive German balloon,
+looming through the mist, and as it is always the desire of a French
+flier to destroy one of these, thus preventing the observer from sending
+by wireless news of the Allied front, he started for this enemy. Jack
+saw his friend's act, and, desiring to aid, turned his machine in the
+same direction.</p>
+
+<p>But they had not gone far before they observed a number of black specks
+in the sky over the German lines.</p>
+
+<p>"The Huns are coming," reflected Tom. "Now for some hot work."</p>
+
+<p>And it came to him, to Jack, and the others, almost before they realized
+it. Tom never got a chance to attack the balloon he hoped to force to
+descend or to set on fire, for his attention was taken up by two German
+machines, which, separating from the others, headed straight for him.
+The lad gave one glance in the direction of Jack, and noted that a
+single Hun craft was about to engage with his chum.</p>
+
+<p>"It's a regular German circus," thought Tom, referring to the number of
+hostile craft. "They delight to go out in numbers."</p>
+
+<p>By this time the battle in the air had begun. It was a fight above the
+clouds, for both the French and the German machines were flying high,
+and had gone up above the bunches of fleecy vapor that now hid the
+ground from sight.</p>
+
+<p>Tom headed straight for one of the Hun machines, seeking to get above
+it, always a point of vantage in an air battle, and as he rushed on he
+realized that his machine was being hit by bullets from one of the Hun
+guns.</p>
+
+<p>Each bullet, as it struck, made a loud noise, as it punctured the
+tightly-drawn linen that covered the wings. But Tom knew that his craft
+could stand a number of such holes, if only the struts, the supports,
+and the guy wires were not broken. He had no time, now, to note what
+Jack or his comrades were doing, for his whole attention was taken up
+with the two Hun machines engaging him.</p>
+
+<p>One seemed to be more skillful than the other, and to this one Tom gave
+his attention first. He emptied a stream of bullets full into this
+flier's craft, noting, after the first few bad shots, which he could
+tell by the tracers, that he had perfect range.</p>
+
+<p>Guiding his craft with one hand and his feet, Tom worked the Lewis gun
+with his other hand, and he had emptied a whole drum at the daring Hun
+before he had the satisfaction of seeing the machine crumple up. Tom's
+bullets had struck some part that had caused the wings to collapse, and
+the airman went down to earth, his craft out of control.</p>
+
+<p>But matters were not to go easy with the American. The other German was
+now in a better position for getting Tom than the latter was for potting
+him, and Tom felt a stream of bullets flying around him. One chipped his
+gun, and another grazed his cheek, the close call making his heart stand
+still for a moment. But he never faltered.</p>
+
+<p>"I've got to get above him," Tom thought fiercely.</p>
+
+<p>He made a risky spiral turn to one side, and began to mount, seeking to
+get in position to fire to better advantage. It was touch and go for a
+while, and he felt, rather than heard, his craft receive several
+bullets.</p>
+
+<p>"If only the gasolene tank isn't hit," thought Tom.</p>
+
+<p>But good fortune in this respect was with him, and he got in a position
+where he could point his machine (and the gun at the same time, for this
+is how the guns are aimed in the single aircraft) at the Hun flier. And
+then Tom sent forth a rain of bullets.</p>
+
+<p>For a moment they seemed to have no effect, and yet Tom knew he had shot
+straight. Then, even while he felt a sharp pain in one hand, showing
+that he had been hit, he saw the other machine start down in a spinning
+nose dive. That meant he was going downward head first, and at the same
+time spinning around like a top.</p>
+
+<p>This spinning nose dive may be intentional or accidental&mdash;that is, with
+the machine in control, or out of control. The spinning nose dive was
+discovered by accident, but is now part of the regular flying features,
+and is often used by aviators to escape from an enemy.</p>
+
+<p>It is almost impossible to hit a plane doing a spinning nose dive, and
+if an aviator is over his own lines he may be able to come out of it
+before he reaches the ground, and so be safe. Many German planes have
+escaped in this way, and often a French airman has thought he has sent
+his enemy down disabled, when, as a matter of fact, the other has merely
+adopted this ruse to get away.</p>
+
+<p>"Well, I don't know whether I got him, or whether he got frightened and
+went down to fool me," thought Tom. "Anyhow they're both out of the way,
+and I can go after the balloon."</p>
+
+<p>But Tom could not, for two reasons. One was that the wound in his hand
+was bleeding profusely, and he knew it ought to be attended to before he
+was incapacitated. Another was that the balloon was being hauled down,
+and as more French planes were in the air now, making a number superior
+to the Huns, the latter turned tail and retreated.</p>
+
+<p>It was inadvisable to follow them over their own lines now, and the
+squadron, or what was left of it, began to retreat. Tom noted the
+absence of three of the French planes, and among the missing was Jack's.</p>
+
+<p>"I wonder if they got him," Tom mused, his heart becoming like lead. His
+eyes sought the air about him, but Jack's machine, which carried a
+little United States flag where it could easily be seen, was not in
+sight.</p>
+
+<p>It was impossible to get any information up in the air. Tom would have
+to wait until they got back to the aerodrome. And he put on speed to get
+there the sooner, in order to end his suspense.</p>
+
+<p>"And the other brave fellows&mdash;I wonder what happened to them," mused
+Tom. In his worry over the fate of Jack and the others he scarcely
+minded the pain in his hand.</p>
+
+<p>He made a good landing, but being rather weak and faint from loss of
+blood, he scarcely heeded the congratulations of his comrades, who had
+received word, by telephone from the front, of the fate of some of the
+Hun machines. "Where's Jack?" Tom gasped, while a surgeon was putting a
+bandage on his hand.</p>
+
+<p>"Right here, old scout!" came the unexpected answer, and Jack himself
+stepped out from amid a throng of airmen. "Why didn't you wait for me?"
+Jack went on. "I was coming back."</p>
+
+<p>"Coming back? Did you come down safely?" asked Tom, beginning to feel a
+little better now. Then Tom realized the futility of his question, for
+was not Jack there in the flesh?</p>
+
+<p>"Of course I came back, old scout," was the answer. "I had hard luck,
+though, but I'd have gone up again if they'd only waited for me."</p>
+
+<p>"What happened?" asked Tom.</p>
+
+<p>"Oh, just after I potted my man&mdash;or at least sent him down out of
+control&mdash;I got a bullet through my gasolene tank. Luckily it didn't set
+the petrol on fire, but I knew I'd better not take any chances. I tried
+to plug up the puncture with some chewing gum, but it wouldn't work.
+Guess the gum they sell now hasn't as much old rubber boot stock in it
+as it used to have. Anyhow it was leaking like a sieve, and I had to
+head for our lines."</p>
+
+<p>"Tough luck!" consoled Tom. Jack did not add that he had, as soon as he
+landed, got into another machine, and was about to go back and join his
+comrades when they returned, having practically won the battle above the
+clouds.</p>
+
+<p>Congratulations were extended to the members of the squadron, who
+accepted their honors modestly enough, as was characteristic of them.</p>
+
+<p>Then, after Tom's wound had been dressed, and he and Jack were talking
+over the events of the day, there came a communication from the
+commander of the air division in that sector. It was an order calling on
+certain men to report at once for special duty. A picked squadron was to
+be detailed for a hazardous enterprise, it was said.</p>
+
+<p>"And our names are there!" cried Jack. "Tom, old man, we're going!"</p>
+
+<p>"But where is it?" asked another American flier named Boughton. "What's
+the game?"</p>
+
+<p>Knowing the secret would be safe with him Tom said:</p>
+
+<p>"We're going to pot the big German cannon that's bombarding Paris!"</p>
+
+
+
+<hr style="width: 65%;" />
+<h2><a name="CHAPTER_XVI" id="CHAPTER_XVI"></a>CHAPTER XVI</h2>
+
+<h3>MISSING</h3>
+
+
+<p>News of the shelling of Paris by the long-range gun had, of course, been
+received at the aerodrome, though there had not, as yet, many details
+come in. Tom and Jack, as the latest arrivals from the big city, were
+called upon to tell all they knew, and they related their experiences in
+the raids, and also told about the various theories of the big gun.</p>
+
+<p>"But how are we going to find it?" asked. Boughton. "It's easy enough,
+of course, for our squadron to go out with a lot of bombs. But where are
+we going to drop 'em?"</p>
+
+<p>"Oh, we're to go to Paris for further instructions before starting on
+the quest," said Tom, who had made some inquiries about the orders
+concerning the picked squadron.</p>
+
+<p>"And they may have discovered its location by this time," added Jack.
+"We know about where it is&mdash;somewhere in the sector between Hamegicourt
+and Condé. The rest ought to be easy."</p>
+
+<p>"Not so easy as it sounds, my friends," put in a French flier. "I know
+that region. It is a big one; and the Germans no doubt have their gun
+well camouflaged. It will not be easy."</p>
+
+<p>"But we'll get it!" asserted Tom.</p>
+
+<p>"Naturally," said the Frenchman, as if that was all there was to it.</p>
+
+<p>Tom's wound was painful, but not dangerous, though it would keep him on
+the ground for a day or two. Though, as a matter of fact, none of the
+members of the picked squadron was allowed to go aloft after the orders
+came detailing them for work in connection with the monster cannon.
+Their places were taken by others who were sent for, some being new
+fliers who were burning to make a name for themselves.</p>
+
+<p>Besides Tom and Jack, in the picked squadron there were Boughton,
+another American, Cerfe and Tierse, two intrepid Frenchmen, and Haught,
+an Englishman, who insisted, but with little success, that his name be
+pronounced as though spelled "Hoo."</p>
+
+<p>These six were to be depended on to find and destroy the German
+cannon&mdash;all of them if there were more than one, as was likely. And to
+this picked squadron other members would be added as need arose. All six
+were skillful fliers, and brave men of the air, as may easily be
+guessed. They were to use whatever type of machine they liked best&mdash;the
+single seaters, the great bombing planes, and, it was even said, one of
+the immense Italian fliers. This last was a craft capable of carrying
+several men and a quantity of supplies and ammunition.</p>
+
+<p>Very soon, then, Tom Raymond and Jack Parmly were on their way to Paris
+again, accompanied by their comrades, and all would soon be engaged in
+the difficult and perilous task of finding the new German long-range
+cannon.</p>
+
+<p>"I suppose you'll make another attempt to find your father?" suggested
+Jack to his chum, as they rode in on the train.</p>
+
+<p>"Indeed I shall, if I have time. I can't understand why I haven't had
+some word before this. There are several possible reasons, of course. If
+it wasn't that we know he got to Rue Lafayette I'd say his ship had been
+sunk 'without a trace,' as the Germans ordered in other cases. But, of
+course, he safely reached this side. Then he just seems to have dropped
+out of sight, for I can't believe he was killed when the shell from the
+big gun hit the house where he had taken lodging. He may have found it
+advisable to return home at once, for some reason, and didn't have a
+chance to leave any word for me, or send me any message. And perhaps he
+hasn't got back to America yet. Then, too, he may be in Germany, a
+prisoner."</p>
+
+<p>"Let us hope not," said Jack, softly, and Tom echoed the wish.</p>
+
+<p>Much as he wished he could devote some time to the search for his
+father, Tom realized that he was working under military orders, and,
+however dear his father was to him, the sacrifice of his personal
+affairs must be made. He knew he would only have time to make some brief
+inquiries, and then he and Jack must go with the squadron to the
+headquarters assigned to it, as near the location of the big German gun
+as possible, and there try to silence it.</p>
+
+<p>The train the picked squadron was traveling on was late, and it was dusk
+when they alighted at the railroad station.</p>
+
+<p>"Think we'll have a chance to see anything of the bombardment?" asked
+Boughton.</p>
+
+<p>"I was going to say I hoped not," answered Tom, "for I wish the beastly
+gun, or guns, would blow up. But that would take away our chance to pot
+'em, and I know we all want to do that. You may see something, though
+they don't bombard at night as often as they do by day. Of late,
+however, before we left, the night firing was more frequent. Possibly
+they have found some means of hiding the gun flashes or of letting them
+mingle with others along a line so the exact location of the big Bertha
+is a matter of doubt."</p>
+
+<p>As they alighted from the train, and were about to seek some taxicabs to
+take them to lodgings that had been assigned them, they all became aware
+of the fact that something unusual was going on. Suddenly the electric
+lights went out, leaving the region about the station, and indeed all of
+Paris, in comparative darkness.</p>
+
+<p>At the same time a motor fire engine rushed screeching through the
+streets, giving an alarm.</p>
+
+<p>"What is it?" cried Boughton. "Is the big gun firing?"</p>
+
+<p>"It's a Zeppelin raid! I was here once before when they had one," said
+the Englishman coolly. "Mind your heads, boys. Just our rotten luck not
+to have a machine to go up after it."</p>
+
+<p>He hurried out into the open street where he could have a view of the
+sky, and the others followed. There was more excitement than during the
+bombardment of the big gun. People were rushing here and there in search
+of safe places, and taxicabs, with their lamps like fireflies in the
+darkness, were skidding hither and yon, their horns calling for a clear
+way.</p>
+
+<p>Suddenly there was a muffled roar, at some distance off. This was
+followed by a hoarse murmur, as though a burst of rage from many throats
+at the unspeakable outrage of the Huns in killing women and children.</p>
+
+<p>At the same time the anti-aircraft guns, with which Paris is so
+efficiently guarded, began to bark and to send their red flashes out
+into the blackness of the night. They were shooting at the Zeppelin, as
+yet unseen by the men of the picked squadron, and the gunners aimed
+according to instructions sent them by wireless from scouts hovering in
+the air above the city.</p>
+
+<p>As soon as word comes from the front, about eighty miles from Paris,
+that a Zeppelin is on its way to raid, an elaborate system of defense is
+put into operation. There are some airmen above Paris all the while,
+frequently as many as forty on sentry duty. But when word comes of a
+Zeppelin raid the whole squadron, numbering close to three hundred, goes
+aloft. By their searchlights, aided by those on the surface, these
+fliers endeavor to pick up the German machine, and, too, they endeavor
+to get near enough to attack it.</p>
+
+<p>This was what was now going on. Pandemonium appeared let loose, and the
+explosion of the German bombs, mingling with the noise of the French
+guns, made Paris seem like a battlefield. Occasionally could be heard,
+when the guns were silenced for a moment, the roar of the many aeroplane
+motors aloft.</p>
+
+<p>The Zeppelin seemed to be over a section of Paris near the Tuileries,
+judging by the bursts of light in that direction. Tom, Jack, and their
+friends wished with all their hearts that they might take a hand in the
+defense, but it was not to be. For perhaps half an hour the
+anti-aircraft guns roared out their defiance to the Hun, and then a
+large flare of gasolene was lighted in a public square.</p>
+
+<p>This was a signal for the aeroplanes to return, for the Zeppelin had
+left, either because she found the situation too perilous for her, or
+because she had used up all her bombs.</p>
+
+<p>The lights were turned on again, and the new arrivals watched the
+aeroplanes returning one by one, being recognized by their lights in the
+air as they moved about like gigantic illuminated insects.</p>
+
+<p>"Well, that's some excitement," observed Tom, as he and the others
+finally succeeded in getting cabs, and started for their destination. "I
+hope no one was killed."</p>
+
+<p>But the bombs of the inhuman Huns had found several marks, and while the
+harm from a military standpoint was small, a number of persons had been
+killed. Some damage had been inflicted on the Zeppelin, it was said
+later, one brave airman saying he got near enough to spray some bullets
+into one of the cabins where a crowd of officers and men were working
+the machine.</p>
+
+<p>"We will be with you a little later," said Tom to the other members of
+the squadron, as, having reached their lodgings, the two chums set out.</p>
+
+<p>"Where are you going?"</p>
+
+<p>"To call on some ladies," answered Jack, for he and Tom had planned to
+see Bessie and her mother.</p>
+
+<p>They reached their own former stopping place, to which they had been
+sent by Major de Trouville, but when they inquired for the Gleasons the
+landlady, who remembered the boys, stared at them in surprise, and said:</p>
+
+<p>"Why, Madam Gleason and her daughter are not here! They went out this
+morning to meet you, and have not come back!"</p>
+
+<p>"To meet us?" gasped Jack.</p>
+
+<p>"Yes, in answer to your note bidding them do so!"</p>
+
+
+
+<hr style="width: 65%;" />
+<h2><a name="CHAPTER_XVII" id="CHAPTER_XVII"></a>CHAPTER XVII</h2>
+
+<h3>SEEKING THE GUN</h3>
+
+
+<p>Tom and Jack gazed blankly at one another. The same thought was in the
+minds of both.</p>
+
+<p>"The spy!"</p>
+
+<p>"That's who did it," declared Tom. "He forged our names to a note&mdash;no
+hard task since neither Bessie nor her mother knows our writing very
+well&mdash;and he's induced them to go some place where he could get them in
+his power again."</p>
+
+<p>"But why?" asked Jack.</p>
+
+<p>"Probably because Potzfeldt wanted him to do it. He still has his eye on
+Mrs. Gleason's property, I presume, if there is any left after his
+robbery."</p>
+
+<p>"It certainly is tough to think that Bessie and her mother have again
+fallen into his clutches!" exclaimed Jack. "And we can't do a thing to
+rescue them. We've got to report with the others in the morning at the
+new aerodrome."</p>
+
+<p>"Yes, but we still have to-night free!" cried Tom. "It will give us
+several hours to make a search, and we'll do it! Do you know where Mrs.
+Gleason and Bessie went in response to this forged note?" he asked the
+landlady.</p>
+
+<p>She mentioned a certain restaurant, not far away, where Tom and his chum
+had frequently eaten with Mrs. Gleason and her daughter.</p>
+
+<p>"She was rather surprised to get the note from you," said the landlady,
+"and wondered why you didn't come yourself. But she supposed it had
+something to do either with your search for your father or with war
+matters, so she did not question the messenger. I heard her mention the
+place where she and Bessie were going, or I would not know."</p>
+
+<p>"How long ago was it?" asked Jack.</p>
+
+<p>"Oh, just before luncheon time. And they haven't come back."</p>
+
+<p>"The scoundrels have a long start of us!" exclaimed Jack. "We'll have to
+do the best we can."</p>
+
+<p>"Better notify the police at once," suggested Tom. "We'll need their
+help."</p>
+
+<p>"That's right," agreed his chum.</p>
+
+<p>Their uniform was an open sesame to the police officials, and a
+detective was at once detailed to go with the boys to the restaurant.
+There, as might have been expected, there was no news. The spy, or
+whoever Potzfeldt's agent was, had been too clever for that. All that
+could be learned from a taxicab driver was that a lady and a girl,
+answering the descriptions of Bessie and her mother, had been met in
+front of the restaurant by a man.</p>
+
+<p>The three, after a short talk, had driven off together in an automobile,
+and that was the last seen of them.</p>
+
+<p>"But we'll get some trace," declared the detective. "It is hard to get
+in or out of Paris now without proper papers. And while, of course, this
+spy may have forged documents, there is a chance that we may intercept
+him and help your friends. Time is against us, but we will do our best."</p>
+
+<p>Tom and Jack knew that. There was nothing else to do, and so, worried as
+they were, they went back to their comrades. Tom made some inquiries
+about his father, but, as he feared, no news had come.</p>
+
+<p>As may be imagined Tom and Jack did not pass a very restful night. The
+Zeppelin raid had set their nerves on edge, as well as those of every
+one else, and it could not be told when the big gun might begin firing
+again. Then the fact of Mrs. Gleason and Bessie being missing, and not
+knowing in what danger they might be, added to the boys' anxiety.</p>
+
+<p>They paid a late visit to the police, hoping for news, but the spy had
+not been apprehended. Then they hurried back to get a little rest
+before starting with their comrades of the air to search for the monster
+gun.</p>
+
+<p>While these events were transpiring, the French army intelligence
+department had not been idle. The officials knew how vitally necessary
+it was, in order not to have the morale of the people of Paris weakened,
+to do something to find and silence the big guns. And first it was
+necessary to discover them.</p>
+
+<p>While this, as yet, had not been done with exactness, owing to the
+concealing tactics of the Germans, it was believed that the long-range
+cannon was hidden in a certain wood near Laon. French airmen had
+endeavored to spy out certain positions there, but an unusually large
+number of German planes had fought them off.</p>
+
+<p>"That's pretty good evidence that there must be something doing,"
+observed Tom, when he heard this information. "Laon is about ten miles
+behind the German lines as they exist at present. Just a breather for a
+good French plane. Jack, that's a trip we'll soon be taking."</p>
+
+<p>"I'll be with you, old scout. How's your hand?"</p>
+
+<p>"Oh, all right now. I can hold the joy stick or work the gun. I'm ready
+for whatever comes along."</p>
+
+<p>The time had come for the picked squadron to leave Paris and assemble
+at the aerodrome assigned to them as their headquarters while the search
+for the big gun was in progress. Sad at having to leave without having
+some word of Mr. Raymond, and without knowing the fate of Bessie and her
+mother, Tom and Jack, nevertheless, bore up well and left with their
+comrades, going out of Paris on a train that would eventually bring them
+to their headquarters.</p>
+
+<p>In a way their mission was a secret one. Yet it was a question if the
+Germans did not guess that something like what really was afoot would be
+undertaken in order to silence the super-cannon. They were up to all the
+tricks of war, and they must have realized that the French would do as
+the Germans themselves would do under similar circumstances.</p>
+
+<p>"Well, this sure is some place!" exclaimed Tom, as they reached the camp
+where they were to stay until the gun had been destroyed, or until some
+other change in plans was necessary. "It's the best aerodrome we've
+struck since we began flying in this war."</p>
+
+<p>"I believe you!" echoed Jack.</p>
+
+<p>The place, though newly established just back of the French lines, where
+they opposed the German trenches, was well fitted up for the purpose to
+which it was to be devoted.</p>
+
+<p>There were a number of canvas hangars for the aeroplanes, there were
+living quarters for the men, a wireless station and a well defended camp
+where the aviators might live in comfort during the periods between
+their flights.</p>
+
+<p>Of course the place was open to attack by German fliers, but this was
+true of every place along the line. Sufficient camouflaging had been
+done, however, to render the spot reasonably secure from bombing. Of
+course a direct attack from in front would be met by the admirable
+French system of defense, and there were plenty of reserves that could
+be brought up if a general advance were attempted by the Germans. But as
+there was no particular place of any military or strategic importance on
+that sector, the worst that was to be feared was an attack from the air.</p>
+
+<p>And this would be guarded against both by the French fliers themselves
+and by a battery of the newest type of anti-aircraft gun.</p>
+
+<p>"They don't seem to have forgotten much," observed Tom, as he and Jack,
+with the others, went to the quarters assigned to them.</p>
+
+<p>"You said something!" exclaimed Jack, admiringly.</p>
+
+<p>Thus had been set up in this locality, where heretofore no aircraft
+activities had been carried on to any extent, a most perfect
+escadrille.</p>
+
+<p>It was designed to destroy the big German cannon. Would it succeed?</p>
+
+<p>That was a question every man of the Allies asked.</p>
+
+<p>Shortly after the arrival of the picked squadron at the camp, which, in
+honor of Tom and Jack had been named "Lincoln," word came in over the
+wireless that the big gun had again fired on Paris.</p>
+
+<p>"It's funny we didn't hear any report of it," said Jack.</p>
+
+<p>"There have been reports enough," Tom remarked. "I've heard the booming
+of distant guns ever since we got near this place. Any one of them may
+have been the monster, or they may have been firing other guns to hide
+the sound of this cannon. Then, too, it may not make as much noise as we
+think it ought to. The Germans may have found a new kind of powder, or
+even some propelling gas, that makes no extraordinary report. In that
+case we couldn't locate the gun by the sound."</p>
+
+<p>"Maybe you're right," agreed Jack. "Anyhow they're firing, that much is
+proved; and it's somewhere over there," and he motioned toward the
+German lines.</p>
+
+<p>Much as the airmen desired to start at once in their search for the
+monster cannon, it was deemed wise to have first a consultation and a
+general understanding of what means should be employed.</p>
+
+<p>Then, too, all the aircraft were new, having been shipped to Camp
+Lincoln and there assembled, and it was desired to test them before
+taking the dangerous flights over the German lines. So the airmen would
+have to spend some time&mdash;perhaps half a week&mdash;in preliminary work.</p>
+
+<p>Meanwhile the great cannon would keep up its deadly, though, from a
+military standpoint, useless work.</p>
+
+<p>And so began the preparation, if such it might be called. Every one,
+from the most daring "ace" to the humblest kitchen helper in the camp,
+was anxious for the day when it could be said that the gun was out of
+commission, or guns, if, as was likely, there was more than one. But the
+men in command knew the value of thoroughness. There must be no failure
+through lack of making proper plans.</p>
+
+<p>But at last everything was in readiness. The planes had been tested,
+keyed up, and the motors run until every part of them was humming like a
+top. Each man felt confidence, not only in himself but in his craft, and
+that meant much. There were several types for the fliers to use,
+single-seaters, the big bombing craft, those equipped for slow flying
+and from which photographs were to be taken, as well as others. The
+taking of photographs was expected to help in revealing the position of
+the hidden gun.</p>
+
+<p>The big Italian plane was not ready, it seemed, to be used, but it would
+be soon, it was said.</p>
+
+<p>Then came the day and the hour when certain members of the picked
+squadron were to take the air to look for the gun. Tom and Jack, to
+their delight, were selected to go.</p>
+
+<p>"What a chance!" exclaimed Jack, as he climbed into his machine, and saw
+that he had plenty of ammunition for the Lewis gun.</p>
+
+<p>"I hope we can make good!" returned Tom.</p>
+
+<p>Then they were away and up, seeking to find the monster cannon that was
+bringing the war into the heart of Paris.</p>
+
+
+
+<hr style="width: 65%;" />
+<h2><a name="CHAPTER_XVIII" id="CHAPTER_XVIII"></a>CHAPTER XVIII</h2>
+
+<h3>A CLOUD BATTLE</h3>
+
+
+<p>For some little time the picked squadron that was intrusted with the
+difficult and dangerous task of locating the big German gun flew over
+the French lines. Below them Tom and Jack could make out various French
+camps, the front and supporting lines of trenches, and various other
+military works. They could see a brisk artillery duel going on at one
+point. They noted the puffs of smoke, but of course could not hear the
+explosions, as their own motors were making too much noise.</p>
+
+<p>Tom and Jack kept within sight of one another, and also within view of
+their comrades. Each plane was marked with a big number so it could be
+distinguished, for the aviators themselves were so wrapped in
+fleece-lined clothes, so attired in gauntlets, goggles and fur boots, as
+protection against the terrible cold of the upper regions, that one's
+closest friend would not recognize him at a near view.</p>
+
+<p>It was the object of this first scouting expedition to make a
+preliminary observation over as wide a range of the enemy's country as
+possible. While it was hoped that the location of the big gun might be
+spied out, it was almost too much to expect to pick out the spot at the
+first trial. The Germans were keen and wary, and undoubtedly they would
+have laid their plans well.</p>
+
+<p>"Well, I don't see any of 'em coming out to dispute our passage,"
+thought Tom, as he looked at his controls and noted by his height gage
+that he was now up about two miles. "There isn't a Boche plane in
+sight."</p>
+
+<p>And the same thing was observed by Jack and the other fliers. The
+Germans seemed to be keeping down, or else were higher up, or perhaps
+hidden by some cloud bank.</p>
+
+<p>That was another hazard of the air. Going into a cloud, or above it
+might mean, on coming out, that one would find himself in the midst of
+enemies.</p>
+
+<p>It is a life full of dangers and surprises. It is this which makes it so
+appealing to the young and brave.</p>
+
+<p>On and on flew the Allied planes, and the eager eyes of the pilots were
+alternately directed toward the earth and then ahead of them, and upward
+to discern the first sight of a Hun machine, if such should venture out.</p>
+
+<p>The fliers were now well over the German lines, and the batteries from
+below began firing at them. This was to be expected, and Tom, Jack and
+the others had gotten used to the bursts of shrapnel all around them.
+They could see the puffs of smoke where the shells burst, but they could
+hear no sounds.</p>
+
+<p>"The 'Archies' are busy this morning," thought Jack, as he noted the
+firing from below, and using the French slang word for the German
+anti-aircraft guns.</p>
+
+<p>He took a quick glance toward Tom's machine to make sure his chum, so
+far, was all right. Assured on this point Jack looked to his own craft.</p>
+
+<p>"Well," he mused, "at this point the 'flaming onions' can't get us, but
+they may pot us as we go down, as we'll have to if we want to get a good
+view of the ground where the big gun may be hidden."</p>
+
+<p>The "flaming onions," referred to by Jack, were rockets shot from a
+ground mortar. They have a range of about a mile, and when a series of
+them are shot upward in the direction of a hostile plane it is no easy
+matter for the aviator to pass through this "barrage." Once a "flaming
+onion" touches an aeroplane the craft is set on fire, and then, unless a
+miracle happens, the aviator falls to his death.</p>
+
+<p>The German gunners, however, could not use these to advantage while the
+French planes kept so high up, though the shrapnel was a menace, for
+the Hun guns shot far and with excellent aim. A number of the scout
+machines were hit, Tom's receiving three bullets through the wings,
+while Jack's engine was nicked once or twice, though with no serious
+damage.</p>
+
+<p>But as for the German planes they declined the combat that was offered
+them. Probably they had different plans in view. It soon became evident
+to Tom, Jack and the others that to fly at that height meant discovering
+nothing down below. The distance was too great. The big gun might be
+hidden almost anywhere below them, but until it was fired, disclosing
+its presence by an unusual volume of smoke, it would not be discovered.
+Also its fire might be camouflaged by a salvo from a protecting battery.</p>
+
+<p>"It's about time he did that," said Tom to himself at last, as he
+noticed Cerfe, who was the leader of the air squadron, dip his plane in
+a certain way, which was the signal for going down. "We've got to get
+lower if we want to see anything," the young aviator went on. "Though
+they may pot some of us."</p>
+
+<p>Down they went, flying comparatively low but at great speed in order to
+offer less of a target to the gunners below them. And, following
+instructions, each pilot noted carefully the section of the German
+trenches beneath him, and the area back of them. They were seeking the
+big gun.</p>
+
+<p>But, though they looked carefully, it could not be seen, and finally
+when one of the French machines was badly hit, and the pilot wounded, so
+that he had to turn back toward his own lines, Cerfe gave the signal for
+the return.</p>
+
+<p>In all this time not a Hun plane had come out to give battle. What the
+reason for this was could only be guessed at. It may have been that none
+of the German machines was available, or that skillful pilots, capable
+of sustaining a fight with the veterans of the French, were not on hand
+just then. However that may have been, Tom, Jack and the others, after
+firing a few rounds from their machine guns at the trenches, though
+without hope of doing much damage, turned back toward Camp Lincoln.</p>
+
+<p>"Well, then you did not discover anything?" asked Major de Trouville,
+who had been transferred and given the command at Camp Lincoln.</p>
+
+<p>"Nothing," answered Jack.</p>
+
+<p>"If it's in the section we covered, it is well hidden," added Tom.</p>
+
+<p>"And I think, don't you know," went on the Englishman, Haught, "that the
+only way we'll be able to hit on the bally mortar is to fly low and take
+photographs."</p>
+
+<p>"That's my idea," said the major. "If we take a series of photographs
+we can develop them, enlarge them, if necessary, and examine them at our
+leisure. I had thought of this, but it's a slow plan, and it
+means&mdash;casualties. But I suppose that can't be avoided. But I wanted to
+try the scouting machines first.</p>
+
+<p>"After all, the taking of photographs from the air of the enemy trenches
+and the land behind them is a most valuable method of getting
+information," he continued.</p>
+
+<p>Men, specially trained for such observation work, examine the
+photographs after the aviators return with the films, and they can tell,
+by signs that an ordinary person would pass over, whether there is a new
+battery camouflaged in the vicinity, whether preparations are under way
+for receiving a large number of troops, or whether a general advance is
+contemplated. Then measures to oppose this can be started. So, Major de
+Trouville was right, photography forms a valuable part of the new
+warfare.</p>
+
+<p>The photographing of the enemy positions is done in big, heavy machines,
+carrying two men. They must fly comparatively low, and have not much
+speed, though they are armed, and it takes considerable of an attack to
+bring them down. But of course the pilot and his observer are in danger,
+and, to protect them as much as possible, scout planes&mdash;the single-seat
+Nieuports&mdash;are sent out in squadrons to hover about and give battle to
+the German aircraft that come out to drive off the photographers.</p>
+
+<p>"We'll undertake that," proceeded Major de Trouville. "I'll order the
+big machine to get ready for an attempt to-morrow at locating the gun."</p>
+
+<p>"Is it still shooting?" asked Jack.</p>
+
+<p>"Yes, it has just been bombarding Paris; but I have no reports yet as to
+the damage done."</p>
+
+<p>"Aren't we doing anything at all?" asked Tom.</p>
+
+<p>"Oh, yes, our batteries are keeping up a fire on the German lines along
+the front behind which we think the gun is concealed, but what the
+results are yet, we don't know."</p>
+
+<p>"Well, let's hope for clear weather to-morrow," suggested Boughton.</p>
+
+<p>The intervening time was occupied by the aviators in getting everything
+in readiness. The machines were inspected, the automatic guns gone over,
+and nothing left undone that could be thought of to give success.</p>
+
+<p>The next day dawned clear and bright, and, as soon as it was light
+enough to make successful photographs, the big machine set out, while
+hovering above and to either side of it were several Nieuports. Tom and
+Jack were each occupying one of these, ready to give battle to the Huns
+above or below the clouds.</p>
+
+<p>In order to distract the attention of the Germans as much as possible
+from the direct front where the airships were to cross the lines, a
+violent artillery fire was maintained on either flank. To this the
+Germans replied, perhaps thinking an engagement was pending. And so,
+amid the roar of big guns, the flying squadron got off.</p>
+
+<p>"Now we'll see what luck we'll have," mused Tom, as he drove his machine
+forward, being one of the large aerial "V" that had for its angle the
+ponderous photographing bi-motored machine.</p>
+
+<p>Over the German lines they flew, and then the Germans awoke to the
+necessity of ignoring the fire on their flanks and began shooting at the
+airships over their heads.</p>
+
+<p>"This ought to bring out their pilots if they have any sporting blood,"
+thought Jack.</p>
+
+<p>And it did. The French and their allies were no more than well over
+German-occupied territory, before a whole German air fleet swarmed up
+and advanced to give battle. They flew high, intending to get above
+their enemies, and so in the most favorable fighting position. But Tom,
+Jack and the others saw this, and also began to elevate their planes.</p>
+
+<p>"We certainly are going up!" mused Tom, as he noted the needle of his
+height gage showing an altitude of twelve thousand feet. "When are they
+going to stop? We're high above the clouds now."</p>
+
+<p>That was true as regarded himself, Jack, and two other French planes.
+But still the Germans climbed. Doubtless some of them were engaging the
+big machine which was low down, trying to take photographs, but Cerfe
+and Boughton were guarding that.</p>
+
+<p>"Here comes one at me, anyhow!" thought Tom, as he saw a Hun machine
+headed for him.</p>
+
+<p>"Well, the sooner it's over the better. Here goes!" and he pressed the
+release of his automatic gun, meanwhile heading his craft full at the
+German to direct the fire, for that is how the guns are aimed in a
+Nieuport, the gun being stationary.</p>
+
+<p>And so began the battle above the clouds.</p>
+
+
+
+<hr style="width: 65%;" />
+<h2><a name="CHAPTER_XIX" id="CHAPTER_XIX"></a>CHAPTER XIX</h2>
+
+<h3>QUEER LIGHTS</h3>
+
+
+<p>Tom Raymond's first few shots went wild, as he noted by the tracer
+bullets. Then, steering his machine with his feet, he brought it around
+a trifle, and, having by a quick action risen above his antagonist, he
+let him have a good round, full in the face. The result was disastrous
+to the German, for suddenly the Hun machine burst into flames, the
+gasolene from the punctured tank burning fiercely, and down it went a
+flaming torch of death.</p>
+
+<p>Tom felt some bullets whistle around him, and one exploded as it struck
+part of his engine, but without injuring it.</p>
+
+<p>"Explosive bullets, are they?" mused the young aviator. "Against all the
+rules of civilized warfare. Well, he won't shoot any more," he thought
+grimly.</p>
+
+<p>But though Tom had come victorious from his engagement with his single
+antagonist, he had no sooner straightened out and begun to take stock of
+the situation, than he became aware that he was in great danger. Above
+him, and coming at him with the swiftness of the wind, were two speedy
+German machines, bent cm his destruction.</p>
+
+<p>They were both firing at him, the angles of attack converging, so that
+if one missed him the other would probably get him.</p>
+
+<p>"I've got to get out of this," Tom reasoned. He headed his plane toward
+the antagonist on his right, shooting upward and firing as rapidly as he
+could, and had the satisfaction of seeing the German swerve to one side.
+The fire was too hot for his liking.</p>
+
+<p>The other, however, came on and sent such a burst of fire at Tom that
+the latter realized it was a desperate chance he was taking. He tried to
+get above his enemy, but the other's plane was the speedier of the two,
+and he held the advantage.</p>
+
+<p>Tom's ammunition was running low, and he realized that he must do
+something. He decided to take a leaf out of the book of the Germans.</p>
+
+<p>"I'll go down in a spinning nose dive," he reasoned. "They'll be less
+likely to hit me then. I'll have to go back, I guess, and get some more
+shots. I used more than I thought."</p>
+
+<p>He sent his last drum at the persistent German, and, noting that the
+other was swooping around to attack again, went into the dangerous
+spinning nose dive.</p>
+
+<p>The Germans may have thought they had disabled their antagonist, for
+this dive is one a machine often takes when the pilot has lost control.
+But in this case Tom still retained it, and when he had dropped out of
+the danger zone, he prepared to straighten out and fly back over his own
+lines.</p>
+
+<p>It is not easy to straighten an airplane after such a dive, and for a
+moment Tom was not sure that he could do it. Often the strain of this
+nose dive, when the machine is speeding earthward, impelled not only by
+its propellers, but by the attraction, of gravitation, is so great as to
+tear off the wings or to crumple them. But after one sickening moment,
+when the craft seemed indisposed to obey him, Tom felt it beginning to
+right itself, and then he started to sail toward the French lines.</p>
+
+<p>He was not out of danger yet, though he was far enough away from the two
+German machines. But he was so low that he was within range of the
+German anti-aircraft guns, and straightway they began shooting at him.</p>
+
+<p>To add to his troubles his engine began missing, and he realized that it
+had sustained some damage that might make it stop any moment. And he
+still had several miles to travel!</p>
+
+<p>But he opened up full, and though the missing became more frequent he
+managed to keep the motor going until he was in a position to volplane
+down inside his own lines, where he was received with cheers by his
+comrades of the camp.</p>
+
+<p>"How goes it?" asked Major de Trouville anxiously.</p>
+
+<p>"I think we are holding them off," said Tom.</p>
+
+<p>He was the first one who had had to return, much to his chagrin. He
+leaped out of his craft, and was about to ask for another to go back and
+renew the battle of the clouds, when he saw the big photographing
+machine returning, accompanied by all but two of the escorting craft.</p>
+
+<p>"A pair missing," murmured the major, as he searched the sky with his
+glasses.</p>
+
+<p>And Tom wondered if Jack's machine was among those that had not headed
+back.</p>
+
+<p>Eagerly he procured a pair of binoculars, and when he had them focused
+he identified one machine after another, at last picking out his chum's.
+It did not seem to be damaged.</p>
+
+<p>But two of the French craft had been brought down&mdash;one in flames, the
+report had it, and the other out of control, and both fell within the
+German lines.</p>
+
+<p>"Did you get any photographs of the big gun?" asked the major, when the
+men in the double machine had made a landing.</p>
+
+<p>"We got lots of views," answered the photographer, "but what they show
+we can't say. As far as having seen the gun goes, we didn't spot it."</p>
+
+<p>"Well, maybe the photographs will reveal it," suggested the major. "Ah,
+but I am sorry for the two that are lost!"</p>
+
+<p>Jack's experience had been less exciting than Tom's. One machine had
+attacked the former, and there had been a hot engagement for a while,
+but the German had finally withdrawn, though to what extent he was
+wounded or his machine damaged Jack did not know.</p>
+
+<p>However, the picked squadron had reason to feel satisfied with their
+efforts. All now depended on the developing of the photographs, and this
+was quickly done. For this part of warfare is now regarded as so
+important that it is possible for a plane to fly over an enemy's
+station, take photographs and have prints in the hands of the commanding
+officer inside of an hour, if all goes well.</p>
+
+<p>Carefully the photographs were examined by men expert in such matters.
+Eagerly they looked to discover some signs of the emplacement of the big
+gun. But one after another of the experts shook his head.</p>
+
+<p>"Nothing there," was the verdict.</p>
+
+<p>"Then we've got to try again," decided Major de Trouville. "We must
+find that gun and destroy it!"</p>
+
+<p>"Well, we're ready," announced Tom, and the others of the picked
+squadron nodded in assent.</p>
+
+<p>And then began an organized campaign to locate the monster cannon. It
+continued to fire on Paris at intervals. Then three days went by without
+any shells falling, and the rumor became current that the gun had burst.
+If this had happened, there was another, or more, to take its place, for
+again the bombarding of the city began.</p>
+
+<p>Meanwhile the air scouts did their best to find the place of the firing.
+Hundreds of photographs were taken, and brave scouts risked death more
+than once in flying low over suspected territory. But all to no purpose.
+Several were killed, but others took their places. Jack was hit and so
+badly wounded that he was two weeks in the hospital. But when he came
+out he was again ready to join Tom in the search.</p>
+
+<p>No word came as to the whereabouts of Bessie and her mother, nor did Tom
+hear anything of his father. The lack of information was getting on the
+nerves of both boys, but they dared not stop to think about that, for
+the army needed their best efforts as scouts of the air, and they gave
+such service gladly and freely.</p>
+
+<p>Every possible device was tried to find the location of the German gun,
+and numerous battles above the clouds resulted at different times during
+the scout work.</p>
+
+<p>On the whole the advantage in these conflicts lay with the armies of the
+Allies, the Germans being punished severely. Once a German plane was
+brought down within the French lines, and its pilot made a prisoner.</p>
+
+<p>It was hoped that some information might be gotten out of the German
+airman that would lead to the discovery of the big gun, but, naturally,
+he did not reveal the secret; and no more pressure was brought to bear
+on him in this matter than was legitimate. The hiding place of the gun
+remained a secret.</p>
+
+<p>Its possible size and the nature of its shooting was discussed every day
+by Tom, Jack and their comrades. In order to make a cannon shoot a
+distance of about eighty miles it was known that it was necessary to get
+the maximum elevation of forty-five degrees. It was also calculated that
+the shell must describe a trajectory the highest point in the curve of
+which must be thirty-five miles or more above the earth. In other words
+the German cannon had to shoot in a curve thirty-five miles upward to
+have the missile fly to Paris. Of course at that height there was very
+little air resistance, which probably accounted for the ability of the
+missile to go so far. That, and the sub-calibre shell, made the
+seemingly impossible come within the range of possibility.</p>
+
+<p>"What are you going to do, Tom?" asked Jack one evening, after an
+unsuccessful day's flight. For Tom was going toward his hangar.</p>
+
+<p>"Going up."</p>
+
+<p>"What for?" Jack went on.</p>
+
+<p>"Oh, no reason in particular. I just feel like flying. We didn't do much
+to-day. Had to come back on account of mist, and we didn't see enough to
+pay for the petrol used. Want to come along?"</p>
+
+<p>"Oh, I might, yes."</p>
+
+<p>Tom and Jack went up, as did several more. But the two remained up
+longer than did the others, and Jack was somewhat surprised to see his
+chum suddenly head for the German lines, but at an angle that would take
+him over them well to the south of where the observation work had been
+carried on.</p>
+
+<p>"I wonder what he's up to," mused Jack; "Guess I'd better follow and
+see."</p>
+
+<p>There was not much chance of an aerial battle at that hour, for dusk was
+coming on. There had been no bombing squadron sent out, which would
+have accounted for Tom going to meet them, and Jack wondered greatly at
+his chum's action.</p>
+
+<p>Still there was no way of asking questions just then, and Jack followed
+his friend. They sailed over the German lines at a good height, and Jack
+could keep Tom in view by noting the lights on his plane.</p>
+
+<p>These were also seen by the Germans below, and the anti-aircraft guns
+began their concert, but without noticeable effect. None of the Hun
+airmen seemed disposed to accept a challenge to fight, so Tom and Jack
+had the upper air to themselves.</p>
+
+<p>Below them the boys could see flashes of fire as the various guns were
+discharged; and at one point in the lines there was quite an artillery
+duel, the French batteries sending over a shower of high explosive
+shells in answer to the challenge from the Boches.</p>
+
+<p>It was not until Jack had followed his chum back to Camp Lincoln, and
+they had made a landing, that a conversation ensued which was destined
+to have momentous effect.</p>
+
+<p>"Jack, did you notice the peculiar colored lights away to the north of
+where we were flying?" asked Tom, as they divested themselves of their
+fur garments.</p>
+
+<p>"You mean the orange colored flare, that turned to green and then to
+purple?" asked Jack.</p>
+
+<p>"That's it. I thought you'd see it. I wonder what it means?"</p>
+
+<p>"Oh, perhaps some signal for a barrage or an attack. Or they may have
+been signaling another battery to try to pot us."</p>
+
+<p>"No, I hardly think so. They didn't look like signal fires. I must ask
+Major de Trouville about that."</p>
+
+<p>"What?" inquired the major himself, who was passing and who heard what
+Tom said.</p>
+
+<p>"Why, we noticed some peculiar lights as we were flying over the German
+lines in the dark. There was an orange flare, followed by a green light
+that changed to purple," answered Tom.</p>
+
+<p>"There was!" cried the major, seemingly much excited. "You don't mean
+it! That's just what we've been hoping to see! Come, you must tell
+Laigney about this."</p>
+
+
+
+<hr style="width: 65%;" />
+<h2><a name="CHAPTER_XX" id="CHAPTER_XX"></a>CHAPTER XX</h2>
+
+<h3>THE BIG GUN</h3>
+
+
+<p>For a moment Tom and Jack did not quite know what to make of the
+excitement of Major de Trouville. And excited he certainly was beyond a
+doubt.</p>
+
+<p>"You must come and tell this to Lieutenant Laigney at once," he said.
+"It may mean something important. Are you sure of the sequence of the
+colors?" he asked. "That makes all the difference."</p>
+
+<p>"There was first an orange tint," said Tom, "which was followed by green
+and purple, the last gradually dying out."</p>
+
+<p>"Orange, green and purple," murmured the major. "Can it be that for
+which we are seeking?"</p>
+
+<p>He hurried along with the boys, seemingly forgetting, in his haste and
+excitement, that he was their ranking officer. But, as has been noted,
+the aviators are more like friends and equals than officers and men.
+There is discipline, of course, but there is none of the rigidity seen
+in other branches of the army. In fact the very nature of the work
+makes for comradeship.</p>
+
+<p>Tom and Jack knew, slightly, the officer to whom Major de Trouville
+referred. Lieutenant Laigney was an ordnance expert, and the inventor of
+a certain explosive just beginning to be used in the French shells. It
+was simple, but very powerful.</p>
+
+<p>"You must tell him what you observed&mdash;the strange colored lights, my
+boys," said the major. "By the way, I hope you carefully noted the time
+of the colored flares."</p>
+
+<p>Tom and Jack had. That was part of their training, to keep a note of
+extraordinary happenings and the time. Often seemingly slight matters
+have an important bearing on the future.</p>
+
+<p>They found Lieutenant Laigney in his quarters, making what seemed to be
+some intricate calculations. He saluted the major and nodded to the
+boys, whom he had met before.</p>
+
+<p>"Lieutenant," began Major de Trouville, "these young gentlemen have
+something to tell you. I want you to think it over in the light of what
+you told me about the action of that new explosive you said the Germans
+might possibly be using."</p>
+
+<p>"Very good, Major. I shall be delighted to be of any service in my
+power," was the answer.</p>
+
+<p>Then Tom and Jack described what they had seen, giving the location of
+the colored lights as nearly as they could, and the exact time they had
+noted them.</p>
+
+<p>"How long would it take a shell to reach Paris, fired at a distance of
+eighty miles from the city?" asked the major.</p>
+
+<p>The lieutenant made some calculations, and announced the result of his
+findings.</p>
+
+<p>"Then," went on the commanding officer, "if a shell was fired from the
+big gun, say at the moment when these two scouts observed the
+tri-colored fire, it should have reached Paris at seven-fifty-three
+o'clock."</p>
+
+<p>"As nearly as can be calculated, not knowing the exact speed of the
+projectile, yes," answered the lieutenant.</p>
+
+<p>Major de Trouville picked up the telephone and asked to be connected
+with the wireless station.</p>
+
+<p>"Have you had any reports of the bombarding of Paris this evening?" he
+asked. "Yes? What time did the first, or any particular shell, arrive?
+Ah, yes, thank you. That is all at present."</p>
+
+<p>He turned to the others, after having listened to the reply and put the
+instrument away.</p>
+
+<p>"One of the shells exploded in a Paris street at seven-fifty-two o'clock
+this evening," he said.</p>
+
+<p>"It beat your calculations by one minute, Lieutenant Laigney."</p>
+
+<p>"Ah! Then this means&mdash;" and the younger officer seemed as excited as the
+major had been when Tom and Jack told him what they had seen.</p>
+
+<p>"It means," finished the commanding officer, "that, in all likelihood,
+these young men have discovered the location of the big German cannon."</p>
+
+<p>"Discovered it!" cried Jack. "Why we didn't see anything!"</p>
+
+<p>"Nothing but those queer lights," added Tom.</p>
+
+<p>Major de Trouville smiled at them, and Lieutenant Laigney nodded his
+head in assent.</p>
+
+<p>"Those queer lights, as you call them," said the ordnance expert, "were
+the flashes of a new explosive. What the Germans call it I do not know.
+For want of a better name we call it Barlite, from the name of Professor
+Barcello, one of our experimenters, who discovered it. But a spy stole
+the secret and gave it to Germany. They must have managed to perfect it,
+though we have not used it as yet, owing to the difficulty in
+constructing a gun strong enough to withstand its terrific power."</p>
+
+<p>"And do you mean they're using this explosive in the big German gun?"
+asked Jack, "And that we really saw it being fired?" cried Tom.</p>
+
+<p>"That is my belief," said the lieutenant. "This explosive burns, when
+fired from a gun, first with an orange flame, changing to green and then
+to purple, as the various gases are given off."</p>
+
+<p>"Those are the very colors we saw!" exclaimed Jack.</p>
+
+<p>"Yes," went on Major de Trouville. "And when I heard you mention them,
+and when I recalled that Lieutenant Laigney had spoken of a certain
+explosive that gave off a tri-colored light, I suspected you had hit on
+the German secret."</p>
+
+<p>"And do you believe we actually saw the giant cannon being fired at
+Paris?" asked Tom.</p>
+
+<p>"Without a doubt. The time of the arrival of one of the shells coincides
+almost to the minute with the time that would elapse after the missile
+was sent on its way, and this was when you saw the queer flashes. You
+have discovered the area where the big gun is placed. All that is needed
+now are some exact observations to give us the exact spot."</p>
+
+<p>"And then we can destroy it!" cried the lieutenant. "Then the menace to
+beloved Paris will have passed!"</p>
+
+<p>"And thanks to our brave American friends!" cried the major, shaking
+hands with Tom and Jack. "You will win promotion for this!" he murmured.</p>
+
+<p>"But the big gun isn't found yet," said Jack.</p>
+
+<p>"Why, if you are right, sir," Tom said to the major, "the shells must
+pass right over our camp."</p>
+
+<p>"They probably do. But at so far above&mdash;several miles up so as to reach
+the height of thirty-five&mdash;that we never know it. We neither see them
+nor hear them. Boys, I believe you have located the big gun! All that
+now remains is to destroy it!"</p>
+
+
+
+<hr style="width: 65%;" />
+<h2><a name="CHAPTER_XXI" id="CHAPTER_XXI"></a>CHAPTER XXI</h2>
+
+<h3>DEVASTATING FIRE</h3>
+
+
+<p>Modestly enough Tom and Jack took the new honors that came to them. As a
+matter of fact they were in no wise sure that they had discovered the
+location of the German giant cannon. It was all well enough to come in
+and report seeing some strange-colored flares of fire. But Tom and Jack
+felt that they wanted to see a thing with their own eyes before surely
+believing.</p>
+
+<p>Of course, though, the French experts knew about what they were talking,
+and the major and the lieutenant seemed very sure of their ground.</p>
+
+<p>"I only hope we have had the good luck to have spotted the beasts'
+machine," said Tom.</p>
+
+<p>"You will have the honor of proving it to yourselves in the morning,"
+Major de Trouville told them. "You shall accompany the first scouting
+party that goes out. We will send out two photographing machines, and
+enough of a squadron to meet anything the Huns can put forth. Paris
+shall be delivered from the Boche pests!"</p>
+
+<p>"We'll do our best," said Tom, and Jack nodded in agreement.</p>
+
+<p>It did not take long for the news to spread about Camp Lincoln that the
+two young United States aviators had, very probably, discovered by
+accident the big German gun.</p>
+
+<p>And in telling what they had seen Tom and Jack remarked that the
+peculiar tri-colored fire had been in the midst of other flashes of
+flame, and, doubtless, smoke, but that could not be seen on account of
+the darkness.</p>
+
+<p>"The other flashes were probably guns fired to camouflage the flash from
+the giant cannon, or possibly cannons," observed Major de Trouville.
+"But we shall see what to-morrow brings forth."</p>
+
+<p>The hours of the night seemed long, but there was much to do to get
+ready for the next day's operations. More aviators were sent for, and
+the men of the air spent many hours tuning up their motors and seeing to
+their guns, while the big machines, which it was hoped could take
+pictures of the giant cannon's position, were gone over carefully.</p>
+
+<p>In addition some powerful French guns were brought up&mdash;some of the
+longest range guns available, and it was hoped that the big aeroplanes
+might signal by wireless the exact location of the super-gun, so that a
+devastating fire could be poured on it, as well as bombs be dropped
+from some machines especially fitted for that work.</p>
+
+<p>Camp Lincoln, where the picked squadron was situated, was in the
+neighborhood of Soissons, France, in a sector held by the French troops.
+The lines of German and French trenches, with No Man's Land in between,
+was about ten miles to the east of this point. This section had changed
+hands twice, once being occupied by the Germans, and then abandoned by
+them when they made the great withdrawal.</p>
+
+<p>Now, perhaps ten miles back of the German trenches, the great gun was
+hidden, making its total distance from Paris about eighty miles, but its
+distance from Camp Lincoln something less than twenty miles.</p>
+
+<p>Modern guns easily shoot that distance, but the commander of the forces
+in this section was going to shorten that. Soissons was the nearest
+large city to the camp. As a matter of fact the air squadron was some
+distance east of that place, and nearer the battleline. So that it was
+comparatively easy, once the location of the big gun was known, to bring
+up heavy artillery behind the French lines to batter away at its
+emplacement.</p>
+
+<p>After a night of arduous labor, during which there was anxiety lest the
+Germans find out what was going on, morning broke, and to the relief of
+all it was bright.</p>
+
+<p>There was an early breakfast, and then the aviators' helpers wheeled the
+machines from the hangars. Several big photographing craft were in
+readiness, and ten bombing planes were in reserve.</p>
+
+<p>Major de Trouville inspected his brave men. They were as eager as dogs
+on the leash to be off and at the throat of the Huns. A wireless message
+from Paris had come in soon after breakfast, stating that nearly a score
+had been killed in the capital the previous night by fire from the
+"Bertha."</p>
+
+<p>"And it's up to us to avenge them!" exclaimed Jack.</p>
+
+<p>"That is what we'll do if we have any luck!" added Tom grimly.</p>
+
+<p>There was a last consultation of the officers, instructions were gone
+over, and everything possible done to insure success. The moment a big
+gun was sighted, the signal was to be given and the French long-range
+cannon would open fire, while the bombing machines would also do their
+part.</p>
+
+<p>"All ready! Go!" called the major, and there was a rattle and a roar
+that drowned his last word. The men of the air were off.</p>
+
+<p>Led by Tom and Jack, the others followed. Up and up they arose, the
+smaller planes flying high as a protection to the more cumbersome
+machines of the bi-motored type. And soon the squadron, the largest that
+had yet ascended from Camp Lincoln, was hovering over the German lines.</p>
+
+<p>The Huns seemed to realize that something more than an ordinary attack
+from the air was impending, for soon after the anti-aircraft guns began
+firing a swarm of German aviators took the air, and there was no
+shirking battle this time. The Huns so evidently felt the desperate need
+of driving away their attackers, that this, more than what the major and
+lieutenant had said, convinced Tom and Jack that they were at last on
+the track of the big gun.</p>
+
+<p>Of course the two boys could not communicate with one another, but they
+said afterward that their thoughts were the same.</p>
+
+<p>The battle of the air opened with a rush and a roar. The Germans, though
+outnumbered by their opponents, did not hesitate, but came on fiercely.
+They attacked first the big photographing planes, for they realized that
+these were the real "eyes" of the squadron. The impressions they
+received, and the views they carried back, might mean the failure of the
+German plans.</p>
+
+<p>But the French were ready for this, and the swift little Nieuports,
+dashing here and there, swooping and rising, attacked the other planes
+vigorously.</p>
+
+<p>It was give and take, hammer and tongs, fire and be fired on, smash and
+be smashed. It was not as one-sided a battle as it would seem it might
+have been owing to the superiority of numbers in favor of the French&mdash;at
+least at first. Several of the Allies' planes were sent down, either out
+of control, or in flames. But the Huns paid dearly for their quarry.</p>
+
+<p>Jack and Tom ran serious risks, for the Germans, realizing that the two
+leading planes had some special mission, attacked them fiercely. Tom
+managed to shake off and disable his antagonist. But Jack's man shot
+with such good aim that he pierced his gasolene tank, and had it not
+been that Jack was able to thrust into the hole one of some wooden plugs
+he had brought along for the purpose, he might have had to come down
+within the German lines. But the wood swelled, filled the hole, and then
+the petrol came out so slowly that there was comparatively little
+danger.</p>
+
+<p>And having, with some of their companions, fought their way through the
+German air patrol, and having escaped with minor damage to their guns,
+Jack and Tom looked down at the place where they had seen the queer
+lights.</p>
+
+<p>And then, high up and at a vantage point, while below them hovered their
+photographing planes, the two young aviators beheld a curious sight.</p>
+
+<p>In German-occupied territory, but on French soil, they saw near a
+railroad junction, where they were fairly well hidden in a camouflaged
+position, not one, but three monster Hun cannons. The guns looked more
+like gigantic cranes than like the accepted form of a great rifled piece
+of armament. The guns were so mounted that they could be run out on a
+small track at the moment of firing, and then propelled back again, like
+some of the disappearing cannon at Sandy Hook and other United States
+forts. Only the German guns advanced and retreated horizontally, while
+the usual method is vertically.</p>
+
+<p>"We've discovered 'em! There they are!" cried Tom, but of course he
+could not hear his own voice above the roar of his motor. But he knew
+that he and Jack were over the very spot where the night before they had
+seen the colored flares from the great guns.</p>
+
+<p>And they had, indeed, by a most lucky chance, located the big German
+guns, for there were three of them. They were placed almost midway
+between the railroad station of Crepyen-Lannois and the two forts known
+as "Joy Hills," forts which had fallen into German hands. There were
+two railroad spur lines from the station, and on these the heavy guns
+were moved to position to fire, and then run back again. Other spur
+lines were under course of construction, Jack and Tom, as well as the
+other airmen, could observe, indicating that other guns were to be
+mounted, perhaps to take the place of some that might be destroyed.</p>
+
+<p>As a matter of fact, as was learned later, there were but two guns in
+service at this time, one of the three having burst.<a name="FNanchor_1_1" id="FNanchor_1_1"></a><a href="#Footnote_1_1" class="fnanchor">[1]</a></p>
+
+<p>Even as the French squadron came hovering over the place where the
+German monster guns were placed, the advance of Tom, Jack and their
+comrades being disputed by the Huns, one of the super-guns was run out
+to fire on its specially constructed platform.</p>
+
+<p>That this should be done in the very faces of the French was probably
+accounted for by the fact that the Germans were taken by surprise. It
+took some little time to arrange for firing one of the big cannons, and
+it was probably too late, after the French airmen were hovering above
+it, to get word to the crew not to discharge it.</p>
+
+<p>As it happened, Tom and Jack, with Boughton, who had kept pace with
+them, witnessed the firing of the big gun. As it was discharged, ten
+other heavy guns, but, of course, of much less range, were fired off,
+being discharged as one to cover the report of the giant mortar. And at
+the same time dense clouds of smoke were sent up from surrounding hills,
+in an endeavor to screen the big gun from aeroplane observation. But it
+was too late.</p>
+
+<p>In another moment, and even as the echoes of the reports of the ten
+cannons and the big gun were rumbling, the bombing machine of the French
+came up and began to drop explosives on the spot. At the same time word
+of the location of the great cannon was wirelessed back to the camp, and
+there began a devastating fire on the guns that had been, and were even
+then, bombarding Paris.</p>
+
+
+
+<hr style="width: 65%;" />
+<h2><a name="CHAPTER_XXII" id="CHAPTER_XXII"></a>CHAPTER XXII</h2>
+
+<h3>OVER THE RHINE</h3>
+
+
+<p>It was a battle of the air and on the ground at the same time. From
+above the French, American and British airmen were dropping tons of
+explosives on the emplacements of the big guns and on the railway spurs
+that brought them to the firing points. It might seem an easy matter for
+an airship flying over a place to drop an explosive bomb on it and
+destroy it. But, on the contrary, it is very difficult.</p>
+
+<p>The bombing plane must be constantly on the move, and it takes a pretty
+good eye to calculate the distance from a great height sufficiently well
+to make a direct hit.</p>
+
+<p>But a certain percentage of the bombs find their mark, and they did in
+this case. Tom and Jack, as well as the other scouts, looking down from
+their planes, saw fountains of brown earth being tossed into the air as
+the French bombs exploded. At the same time the photographers in the
+other planes were making pictures of the guns and their location.</p>
+
+<p>They were hindered in this not only by the shooting of the Germans from
+below, who were working their anti-aircraft guns to their capacity, but
+by screens of smoke clouds, which were emitted by a special apparatus to
+hide the big guns. At the same time other cannons were being fired to
+disguise the sound from the immense long-range weapon, but this was of
+little effect, now that the location had been discovered.</p>
+
+<p>Meanwhile a score or more of the Hun planes appeared in the air. They
+had taken flight as soon as their pilots saw the squadron of enemy
+machines approaching, and were eager, this time, to give battle.</p>
+
+<p>"Our work's being cut out for us," murmured Tom, as he steered his
+machine to engage a German who seemed eager for the fray. Tom sent a
+spray of bullets at his enemy, and was fired at in turn. He knew his
+craft had been hit several times, but he did not think it was seriously
+damaged.</p>
+
+<p>Jack, too, as he could tell by a quick glance, was also engaged with a
+German, but Tom had no time then to bestow on mere observation. His
+antagonist was a desperate Hun, bent on the utter destruction of Tom's
+machine. They came to closer quarters.</p>
+
+<p>Down below the fighting was growing more furious. It was in the form of
+an artillery duel. For now the French observation machines were
+wirelessing back the range, and French shells were falling very near the
+big guns.</p>
+
+<p>The heavy guns, in modern warfare, are placed miles away from the
+objects they wish to hit, and the only way to know where the targets are
+is by aeroplane observation. When the guns are ready to fire one of the
+artillery control planes goes up over the enemy's territory. Of course
+it is the object of the enemy to drive it away if possible.</p>
+
+<p>But, hovering in the air, the observer in the double-motored machine
+notes the effect of the first shot from his side's cannon. If it goes
+beyond the mark he so signals by wireless. If it falls short he sends
+another signal. Thus the range is corrected, and finally he sees that
+the big shells are landing just where they are needed to destroy a
+battery, or whatever is the object aimed at. The observation complete,
+the machine goes back over its own lines&mdash;if the Germans let it.</p>
+
+<p>This sort of work was going on below them while Tom, Jack and the others
+in the Nieuports were engaging in mortal combat with the Hun fliers.
+Some of the heavy French shells fell beyond the emplacements of the big
+guns, and others were short. The observers quickly made corrections by
+wireless for the gunners. Tom Raymond, after a desperate swoop at his
+antagonist, sent him down in flames, and then, seeking another to
+engage, at the same time wondering how Jack had fared, the young aviator
+looked down and saw one of the largest of the French shells fall
+directly at the side of the foremost of the three German giant cannons.</p>
+
+<p>There was a terrific explosion. Of course, Tom could not hear it because
+of his height and the noise his motor was making, but he could see what
+happened. A great breach was made in the long barrel of the German gun,
+and its emplacement was wrecked, while the men who had been swarming
+about the place like ants seemed to melt into the earth. They were
+blotted out.</p>
+
+<p>"One gone!" exclaimed Tom grimly. And then he noted that the other two
+guns had been withdrawn beneath the camouflage. They were no longer in
+sight, and hitting them was a question of chance.</p>
+
+<p>Still the French batteries kept up their fire, hoping to make another
+hit, but it would be a matter of mere luck now, for the guns were out of
+observation.</p>
+
+<p>The airmen observers, however, still had a general idea of where the
+super-weapons were, and the French gunners continued to send over a rain
+of shells, while the bombing machines, save one that had been destroyed
+by the German fire, kept dropping high explosives in the neighborhood.</p>
+
+<p>"The place will be badly chewed up, at any rate," mused Tom.</p>
+
+<p>He glanced in the direction where he had last seen Jack, and to his
+horror saw his chum's machine start downward in a spinning nose dive.</p>
+
+<p>"I wonder if they've got him, or if he's doing that to fool 'em,"
+thought Tom. As he was temporarily free from attack at that instant he
+started toward his friend. Hovering over him, and spraying bullets at
+Jack, was a German machine, and Tom realized that this fighter might
+have injured, or even killed, Jack.</p>
+
+<p>"Well, I'll settle your hash, anyhow!" grimly muttered the young birdman
+to himself. He sailed straight for the Hun, who had not yet seen him,
+and then Tom opened fire. It was too late for the German to turn to
+engage his second antagonist, and Tom saw the look of hopelessness on
+his face as the bullets crashed into his machine, sending it down a
+wreck.</p>
+
+<p>"So much for poor old Jack!" cried Tom.</p>
+
+<p>They were well over the German lines now, and the fight was going
+against the French. That is, they were being outnumbered by the Hun
+planes, which were numerous in the air. But the French had accomplished
+their desperate mission. One of the German guns was out of commission,
+and perhaps others, while the location had been made "considerably
+unhealthy," as Boughton expressed it afterward.</p>
+
+<p>It was time for the French to retire, and those of their machines that
+were able prepared to do this. But Tom was going to see first what
+happened to Jack before he returned to his lines.</p>
+
+<p>"He may be spinning down, intending to get out of a bad scrape that way,
+and then straighten for a flight toward home," mused Tom. "Or he may
+be&mdash;"</p>
+
+<p>But he did not finish the sentence.</p>
+
+<p>There was but one way for Tom to be near Jack when the latter landed&mdash;if
+such was to be his fate&mdash;and to give him help, provided he was alive.
+And that was for Tom himself to go down in a spinning nose dive, which
+is the speediest method by which a plane can descend. But there is great
+danger that the terrific speed may tear the wings from the machine.</p>
+
+<p>"I'm going to risk it, though," decided Tom.</p>
+
+<p>Down and down he spun, and as he looked; he became aware, to his joy,
+that Jack had his machine under some control.</p>
+
+<p>"He isn't dead yet, by any means," thought Tom. "But he may be hurt. I
+wonder if he can make a good landing? If he does it will be inside the
+German lines, though, and then&mdash;"</p>
+
+<p>But Tom never faltered. He must rescue his chum, or attempt to, at all
+hazards.</p>
+
+<p>Down went both machines, Jack's in the lead, and then, to his joy, Tom
+saw his friend bring the machine on a level keel again and prepare to
+make a landing. This was in a rather lonely spot, but already, in the
+distance, as Tom could note from his elevated position, Germans were
+hurrying toward the place, ready to capture the French machine.</p>
+
+<p>"If he's alive I'll save him!" declared Tom. "My machine will carry
+double in a pinch, but he'll have to ride on the engine hood."</p>
+
+<p>Tom was going to take a desperate chance, but one that has been
+duplicated and equalled more than once in the present war. He was going
+to descend as near Jack's wrecked machine as he could, pick up his chum,
+and trust to luck to getting off again before the Germans could arrive.</p>
+
+<p>That Jack was once more master of his craft became evident to his
+friend. For the Nieuport was slowing down and Jack was making ready for
+as good a landing as possible under the circumstances. It was plain,
+however, that his machine was damaged in some way, or he would have gone
+on flying toward his own lines.</p>
+
+<p>Tom saw his chum drop to the ground, and then saw him quickly climb out
+of his seat, loosing the strap that held him in. By this time other
+German planes were swooping toward the place, and a squad of cavalry was
+also galloping toward it.</p>
+
+<p>"I'll beat you, though!" cried Tom fiercely.</p>
+
+<p>He throttled down his engine, intending to give it just enough gas to
+keep it going, for he would have no one to start it for him if the motor
+stalled. He calculated that he could taxi the craft across the ground
+slowly enough for Jack to jump on and then he could get away, saving
+both of them.</p>
+
+<p>Jack understood the plan at once. He waved his hand to Tom to show that
+he would be ready, and Tom felt a joy in his heart as he realized that
+his chum was uninjured.</p>
+
+<p>Down to the ground went Tom, and he guided his machine toward Jack,
+standing beside his own damaged craft, waiting. Suddenly there was a
+sharp report, and Tom saw Jack's machine burst into flames.</p>
+
+<p>"He fired into the gasolene tank!" thought Tom. "That's the boy! He
+isn't going to let the Huns get his machine and the maps and
+instruments. Good!"</p>
+
+<p>Jack leaped back from the blaze that suddenly enveloped his aeroplane
+and then ran toward Tom's machine. As he leaped upon the engine hood,
+which he could do with little more risk than boarding a swiftly moving
+trolley car, there was a burst of rifle fire from the cavalry, some of
+which had reached the scene.</p>
+
+<p>Jack gave a gasping cry, and fell limp. He almost slipped from the motor
+hood, but with one hand Tom quickly fastened his companion's life belt
+to the support and then, knowing Jack could not fall off, opened his
+engine wide.</p>
+
+<p>Across the ground the double-loaded craft careened, while the cavalry
+opened fire.</p>
+
+<p>"If they hit me now, it's all up with both of us!" thought Tom
+desperately.</p>
+
+<p>But though the bullets splattered all around him, and some hit the
+machine, neither he nor Jack was struck again, nor was any vital part of
+the machinery damaged. Poor Jack, though, seemed lifeless, and Tom
+feared he had arrived the fraction of a minute too late.</p>
+
+<p>Then up rose Tom's plane, up and up, the powerful engine doing its best,
+though the machine was carrying double weight. But the Nieuports are
+mechanical wonders, and once the craft was free of the earth it began
+climbing. Fortunately there were no swift German machines near enough to
+give effective chase, though some of the heavier bi-motored craft opened
+fire, as did the cavalry from below, as well as some of the
+anti-aircraft guns.</p>
+
+<p>But Tom, keeping on full speed, soon climbed up out of danger, and then
+swung around for a flight toward his own lines. He could see, ahead of
+him, the fleet of French planes, going back after the raid on the big
+guns. Tom's plane was the rearmost one.</p>
+
+<p>Then he knew that he was safe! But he feared for Jack!</p>
+
+<p>One after another, such as were left of the raiding party landed. Their
+comrades crowded around them, congratulating them with bubbling words of
+joy. Yet there was sorrow for those that did not return.</p>
+
+<p>"Is he dead?" asked Tom, as orderlies quickly unstrapped Jack, and
+prepared to carry him to the hospital. "Is he dead?"</p>
+
+<p>"Alive, but badly wounded," said a surgeon, who made a hasty
+examination.</p>
+
+<p>And then all seemed to become dark to Tom Raymond.</p>
+
+<p>"Well, Jack, old man, how do you feel?"</p>
+
+<p>"Oh, pretty good! How's yourself?"</p>
+
+<p>"Better, now that they've let me in to see you."</p>
+
+<p>"You got the big guns, I understand."</p>
+
+<p>"You mean <i>you</i> did, too. It was as much your doings as mine. Yes, we
+sprayed 'em good and proper. They won't fire on Paris again right away,
+but I suppose they'll not give up the trick, once they have learned it.
+But we have their number all right. Now you want to hurry up and get
+well."</p>
+
+<p>Jack was in the hospital recovering from several bullet wounds. They had
+not been as dangerous as at first feared, but they were bad enough. Tom
+had come to see him and give some of the details of the great raid,
+which Jack had been unable to hear because of weakness. Now he was
+convalescing.</p>
+
+<p>"What's the idea of hurry?" asked Jack. "Are we going after more big
+cannon?"</p>
+
+<p>"No, this is a different stunt now. We're going over the Rhine."</p>
+
+<p>"Over the Rhine?" and Jack sat up in bed.</p>
+
+<p>"Monsieur&mdash;I must beg&mdash;please do not excite him!" exclaimed a pretty
+nurse, hurrying up. "The doctor said he must keep quiet."</p>
+
+<p>"But I want to hear about this," insisted Jack. "Over the Rhine! Say,
+that'll be great! Carrying the war into the enemy's country for fair!"</p>
+
+<p>"I'll tell you a little later," promised Tom, moving away in obedience
+to an entreaty from the nurse.</p>
+
+
+
+<hr style="width: 65%;" />
+<h2><a name="CHAPTER_XXIII" id="CHAPTER_XXIII"></a>CHAPTER XXIII</h2>
+
+<h3>OFF FOR GERMANY</h3>
+
+
+<p>Whether it was Tom's news or Jack's natural health was not made clear,
+but something certainly caused Jack Parmly to recover strength much more
+rapidly then the surgeons had believed possible, so that he was able to
+leave the hospital soon after Tom's visit.</p>
+
+<p>"And now I want you to explain what you meant by saying we were to go
+over the Rhine," Jack insisted to his chum. "I've been wondering and
+thinking about it ever since you mentioned it, but none of them would
+tell me a thing."</p>
+
+<p>"No, I reckon not," chuckled Tom.</p>
+
+<p>"Why, you old sphinx?"</p>
+
+<p>"Because they didn't know. It's a secret."</p>
+
+<p>"Can you tell me?"</p>
+
+<p>"Sure! Because you're going to be in it if you are strong enough."</p>
+
+<p>"Strong enough? Of course I'll be! Why, I'm feeling better every minute!
+Now you go ahead and relieve my anxiety. But first tell me&mdash;have you had
+any news of your father?"</p>
+
+<p>Tom shook his head.</p>
+
+<p>"Not a word," he answered. "I'm beginning to feel that he has been
+captured by the Germans."</p>
+
+<p>"That's bad," murmured Jack. "And now, have you heard anything about&mdash;"</p>
+
+<p>"Bessie and her mother?" finished Tom, breaking in on his chum's
+question with a laugh. "Yes, I'm glad I can give you good news there.
+They are all right, and I have a letter from Bessie for you. She wants
+you to come and see her."</p>
+
+<p>"You have a letter? Why didn't you give it to me before? You fish!"</p>
+
+<p>"It just came. And so did news about their safety."</p>
+
+<p>"Then the spy didn't get 'em after all."</p>
+
+<p>"Oh, yes, he got 'em all right! But he bungled the job, or rather,
+Bessie bungled it for him. They were rescued, and the spy was locked up.
+We're to go to Paris to see them. They'll tell us all about it then."</p>
+
+<p>"But what has that to do with our going over the Rhine?"</p>
+
+<p>"Nothing. We're to go to Paris for a rest, and to get in shape for a big
+effort against the Germans. I'll tell you about it."</p>
+
+<p>"Forge ahead, then."</p>
+
+<p>Tom got up to look at the doors and windows of the French cottage back
+of the lines, where Jack had been moved to complete his recovery. Tom
+and Jack, after the sensational raid, had been given leave of absence.</p>
+
+<p>"I just want to make sure no one hears what I say, for it's a dead
+secret yet," Tom went on. "But this is the plan. The French have several
+of the biggest and newest Italian planes&mdash;planes that can carry half a
+dozen men and lots of ammunition. Our aerodrome is going to be shifted
+to the Alsace-Lorraine front, and from there, where the distance to
+German territory is shorter than from here, we are to go over the Rhine
+and bombard some of their ammunition and arms factories, and also
+railroad centers, if we can reach 'em."</p>
+
+<p>"Good!" cried Jack. "I'm with you from the fall of the hat!"</p>
+
+<p>"First you've got to build up a little," stated Tom. "There is no great
+rush about this Rhine-crossing expedition. A lot of plans have to be
+perfected, and we've got to try out the Italian plane. And, before that,
+we are to go to Paris."</p>
+
+<p>"Who says so?"</p>
+
+<p>"Major de Trouville. He's greatly pleased with the result of the raid on
+the big German guns, and says we're entitled to a vacation. Also he
+knows I want to make some more inquiries about my father. But I fear
+they will be useless," and Tom sighed.</p>
+
+<p>"And are we to go to see Mrs. Gleason?" asked Jack.</p>
+
+<p>"Yes. And Bessie, too. They'll tell us all that happened."</p>
+
+<p>A few days later, having received the necessary papers, Tom and Jack
+were once more on their way to the capital. And this time they did not,
+with others, have to suffer the danger and annoyance of the long-range
+bombardment. It was over for a time, but there was no guarantee that the
+Germans would not renew it as soon as they could repair the damage done
+to their giant cannons.</p>
+
+<p>The boys found Bessie and her mother in lodgings in a quiet part of
+Paris, and were met with warm greetings. Then the Gleasons told their
+story.</p>
+
+<p>They had been inveigled out of their lodgings by the false note from the
+boys, and had immediately been taken in charge by the spy, who, it was
+proved, was an agent of the infamous Potzfeldt. But Bessie, after
+several days' captivity in an obscure part of the great city, managed to
+drop a letter out of the window, asking for help.</p>
+
+<p>The police were communicated with, and not only rescued Mrs. Gleason and
+her daughter, but caught the spy as well, and secured with him papers
+which enabled a number of Germany's ruthless secret service agents to be
+arrested.</p>
+
+<p>It was because of the necessity for keeping this part of the work quiet
+that no word of the rescue of Bessie and her mother was sent to the boys
+until after the big gun raid.</p>
+
+<p>There was much to be talked about when the friends met once more, and
+Mrs. Gleason said she and Bessie were going back to the United States as
+soon as they could, to get beyond the power of Potzfeldt.</p>
+
+<p>As Tom had feared, there was no news of his father, but he did not yet
+give up all hope.</p>
+
+<p>"If he's a prisoner there's a chance to rescue him," he said.</p>
+
+<p>The time spent in Paris seemed all too short, and it came to an end
+sooner than the boys wished. Jack was almost himself again, though he
+limped slightly from one of the German bullets in his leg. There was
+every hope, however, that this would pass away in time.</p>
+
+<p>Good-byes were said to Bessie and her mother, and once more the two Air
+Service boys reported to their aerodrome. There they found not one, but
+two, of the big Italian machines, which are capable of long flight,
+carrying loads that even the most ponderous bombing plane would be
+unable to rise with.</p>
+
+<p>Preparations for the bold dash into the enemy's country went on
+steadily and swiftly. Tom and Jack were trained in the management of the
+big birds of the air, and though it was essentially different from what
+they had been used to in the Nieuports and the Caudrons, they soon
+mastered the knack of it, and became among the most expert.</p>
+
+<p>"I believe I made no mistake when I picked them to be part of the
+raiding force," said Major de Trouville.</p>
+
+<p>"Indeed you did not," agreed Lieutenant Laigney. "Their work in
+discovering the big guns, and their help in silencing them, showed what
+sort of boys they are."</p>
+
+<p>And finally the day came when those who were to take part in the raid
+across the Rhine were to proceed to a point within the French lines from
+which the start was to be made.</p>
+
+<p>Other Italian planes would await them there, and there they would
+receive final instructions.</p>
+
+<p>They bade farewell to their comrades in Camp Lincoln, and were given
+final hand-shakes, while more than one, struggling to repress his
+emotion wished them "<i>bonne chance</i>!"</p>
+
+<p>This raid against one of the largest and most important of the German
+factory and railroad sections had long been contemplated and details
+elaborately worked out for it. The start was to be made from the nearest
+point in French-occupied territory, and it was calculated that the big
+Italian machines could start early in the evening, cross the Rhine,
+reach their objective by midnight, drop the tons of bombs and be back
+within the French lines by morning.</p>
+
+<p>Such, at least, was the hope. Whether it would be realized was a matter
+of anxious conjecture.</p>
+
+<p>At last all was in readiness. The final examinations of the machines and
+their motors had been made and the supplies and bombs were in place.</p>
+
+<p>"Attention!" called the commander. "Are you ready?"</p>
+
+<p>"Ready!" came from Tom, who was in command of one machine.</p>
+
+<p>"Ready!" answered Haught, who was in charge of the second.</p>
+
+<p>"Then go, and may good fortune go with you!"</p>
+
+<p>There was a roar of the motors, and the big, ponderous machines started
+for Germany.</p>
+
+<p>Would they ever reach it?</p>
+
+
+
+<hr style="width: 65%;" />
+<h2><a name="CHAPTER_XXIV" id="CHAPTER_XXIV"></a>CHAPTER XXIV</h2>
+
+<h3>PRISONERS</h3>
+
+
+<p>Under the evening stars, the two big Italian machines slowly, and, it
+must be said, somewhat ponderously, as compared with a speedy Nieuport,
+winged their way toward the German river, behind which it was hoped,
+some day, to drive the savage Huns.</p>
+
+<p>"What do you think?" asked Jack of his chum, for in these latest
+machines, by reason of the motors being farther from the passengers, and
+by means of tubes, some talk could be carried on.</p>
+
+<p>"I don't know just what to think," was the answer. "So much has happened
+of late, that it's almost beyond my thinking capacity."</p>
+
+<p>"That's right. And yet I can guess one thing you have in mind, Tom, old
+scout."</p>
+
+<p>"What is it?"</p>
+
+<p>"Your father! You're hoping you can rescue him."</p>
+
+<p>"That's right, I am. And as soon as this drive is over&mdash;if we come back
+from it with any measure of success, and I can get a long leave of
+absence&mdash;I'm going to make a thorough search for him."</p>
+
+<p>"And I'll be with you; don't forget that!"</p>
+
+<p>There was not time for too much talk of a personal nature, as Tom and
+Jack had to give their attention to the great plane. The motors were
+working to perfection, and with luck they should, within a few hours, be
+over the great German works, which they hoped to blow up.</p>
+
+<p>Tom was in charge of the plane, but he had Jack and others to help him,
+and there was a certain freedom of movement permitted, not possible in
+even the big photographing or bombing planes.</p>
+
+<p>Down below little could be seen, for they were now over the French and
+German trenches, and neither side was showing lights for fear of
+attracting the fire of the other.</p>
+
+<p>But Tom and Jack had been coached in the course they were to take and,
+in addition, they had a pilot who, a few weeks before, had made a
+partially successful raid in the region beyond the Rhine, barely
+escaping with his life.</p>
+
+<p>And so they flew on under the silent stars, that looked like the small
+navigating lights on other aeroplanes. But, as far as the raiders knew,
+they were the only ones aloft in that particular region just then. They
+had risen to a good height to avoid possible danger from the German
+anti-aircraft guns. There was not much danger from the German planes,
+as, of late, the Huns had shown no very strong liking for night work,
+except in necessary defense.</p>
+
+<p>Off to the left Tom and Jack could see the other big Italian plane, in
+charge of Haught. It carried only small navigating lights, carefully
+screened so as to be invisible from below.</p>
+
+<p>"I suppose you understand the orders," said Tom, speaking to Jack.</p>
+
+<p>"Well, we went over them; but it wouldn't do any harm to refresh my
+memory. You're to be in general charge of the navigation of the plane,
+and I'm to see to dropping the bombs&mdash;is that it?"</p>
+
+<p>"That's it. You'll have to use your best judgment when it comes to your
+share. I'll get you over the German works and railroad centers, as
+nearly as I can in the dark, and then it will be up to you."</p>
+
+<p>"I hope I don't fail," said Jack, speaking through the tube.</p>
+
+<p>"You won't. Don't get nervous. Any kind of a hit will throw a scare into
+the Huns, and make them feel that they aren't the only ones who can make
+air raids. But in this case we're not bombing a defenseless town, and
+killing women and children. This is a fortified place we're going over,
+and it's well defended."</p>
+
+<p>"Some difference," agreed Jack.</p>
+
+<p>"And if we can get some direct hits," went on Tom, "and blow to
+smithereens some of their munition or armament factories, we'll be so
+much nearer to winning the war."</p>
+
+<p>And that, in brief, was the object of the flight over the Rhine.</p>
+
+<p>Once more the boys fell silent.</p>
+
+<p>On and on swept the planes. Whether the Germans beneath were aware of
+the danger that menaced them, it is impossible to say. But they made no
+attempt to fire on the Italian craft. Probably because of the darkness,
+and owing to the great height at which they flew, the Huns were in
+ignorance of what was taking place.</p>
+
+<p>On and on in the night and beneath the silent stars they flew. Now Tom
+and the pilot began watching for some landmark&mdash;some cluster of lights
+which would tell them their objective was within sight. But for another
+hour nothing was done save to guide the big craft steadily onward.</p>
+
+<p>Once, as Jack looked down, he saw what seemed to be a city, and he
+thought this might be the place where the great factories were situated.</p>
+
+<p>"No, it's an important town," Tom said, in answer to his chum's
+inquiries, "but it is only a town&mdash;not a fortress, as the Huns call
+London. That isn't fair game for us."</p>
+
+<p>But half an hour later the pilot spoke sharply, and gave an order. He
+pointed downward and ahead and there a faint glow, and one that spread
+over a considerable area, could be made out.</p>
+
+<p>"That is where we are to drop the bombs," said Tom to Jack.</p>
+
+<p>The other machine, which had flown somewhat behind the one in which were
+the two chums, now swerved over at greater speed. Her pilot, too, had
+picked up the objective.</p>
+
+<p>And now began the most dangerous part of the mission. For it would not
+do to drop the bombs from too great a height. There was too much risk of
+missing the mark. The planes must descend, and then they would be within
+range of the defensive guns.</p>
+
+<p>But it had to be done, and the order was given. As Jack and Tom went
+lower, in company with the other plane, they observed that they were
+over a great extent of factory buildings, where German war work was
+going on.</p>
+
+<p>And now the noise of their motors was heard. Searchlights flashed out
+below them, and stray beams picked them up. Then the anti-aircraft guns
+began to bark.</p>
+
+<p>"We're in for a hot time!" cried Jack.</p>
+
+<p>"You said it!" echoed Tom, as he steered the great plane to get into an
+advantageous position.</p>
+
+<p>Through a glare of light, and amid a hail of shots, the great airships
+rushed down to hover over the German factories. They would not let go
+their bombs until in a position to do the most damage, and this took a
+little time.</p>
+
+<p>"How about it, Tom?" asked Jack, for he was anxious to begin dropping
+the bombs.</p>
+
+<p>"Just another minute. We'll go down a little lower, and so do all the
+more damage."</p>
+
+<p>And down the airship went. She was hit several times, for shrapnel was
+bursting all around, but no material damage was done, though one of the
+observers was wounded.</p>
+
+<p>"Now!" suddenly signaled Tom.</p>
+
+<p>"There they go!" shouted Jack, and he released bomb after bomb from the
+retaining devices.</p>
+
+<p>Down they dropped, to explode on striking, and the loud detonations
+could be heard even above the roar of the motors. Tom noted that the
+other machine was also doing great destruction, and he saw that their
+object had been accomplished.</p>
+
+<p>Several fires broke out below them in different parts of the factory
+property, and soon the Germans had to give so much attention to saving
+what they could, that their fire against the hostile airships noticeably
+slackened.</p>
+
+<p>"Any more bombs left, Jack?" asked Tom.</p>
+
+<p>"A few," answered his chum.</p>
+
+<p>"Let 'em have it now. We're right over a big building that seems to be
+untouched."</p>
+
+<p>Down went the bombs, and such an explosion resulted that it could mean
+but one thing. They had set off a munition factory. This, as the boys
+afterward learned, was the case.</p>
+
+<p>So great was the blast that the great plane skidded to one side, and a
+moment later there came a cry of alarm from some of the crew.</p>
+
+<p>"What's the matter?" shouted Tom.</p>
+
+<p>"Out of control," was the answer. "One of the motors has stopped, and
+we've got to go down."</p>
+
+<p>"Can't we go up?"</p>
+
+<p>"No!" was the despairing answer. "We've got to land within the German
+lines."</p>
+
+<p>And down the great Italian plane went, while her sister ship of the air
+sailed safely off, for it would have been foolhardy for her to have
+tried to come to the rescue.</p>
+
+<p>The crew worked desperately to send their craft up again, but it was
+useless. Lower and lower she went, fortunately not being fired at, so
+great was the confusion caused by the destruction of the factories.</p>
+
+<p>"Take her down as far away as possible from this scene," said Tom to one
+of his men. "If we land in a lonely place we may be able to make repairs
+and get up again."</p>
+
+<p>"I will," was the answer.</p>
+
+<p>Through the light from the burning buildings, a spot in a level field
+was selected for a landing. And down the Italian plane went.</p>
+
+<p>A hasty examination showed little wrong with the motor, and this little
+was quickly repaired.</p>
+
+<p>But the hope of getting the airship to rise again was frustrated, for
+just as the raiding party was about to take its place in the machine
+again, a company of German soldiers came running over the fields,
+demanding the surrender of the intrepid men of the air. There was
+nothing else to do&mdash;no time to set the craft on fire.</p>
+
+<p>So it fell into the hands of the Germans! Tom, Jack and the others were
+prisoners!</p>
+
+
+
+<hr style="width: 65%;" />
+<h2><a name="CHAPTER_XXV" id="CHAPTER_XXV"></a>CHAPTER XXV</h2>
+
+<h3>THE ESCAPE</h3>
+
+
+<p>"Well, this is tough luck!"</p>
+
+<p>"Tough is no name for it, Jack. It's the worst ever! I don't suppose
+they'll do a thing to us after what we did to the factories."</p>
+
+<p>"No. We certainly scotched 'em good and proper. Everything went off like
+a tea party, except our coming down. And we could have gotten up again,
+only those Germans didn't give us a chance."</p>
+
+<p>"You can't blame 'em for that."</p>
+
+<p>"No, I suppose not. But it's hard lines. I wonder why they're keeping us
+here?"</p>
+
+<p>Tom and Jack were talking thus while held prisoners by the Germans,
+after the airship raid over the Rhine. It was an hour after they had
+been forced to descend.</p>
+
+<p>So sudden had been the rush of the German infantry that no chance was
+had to destroy the great Italian plane, and it, and all the crew,
+including the two Air Service boys, had been overpowered, and disarmed.
+They were thrust into what might pass for a guardhouse, and then, a
+guard having been posted, the other soldiers hurried back to aid in
+fighting the fire which had been started in the great factories, and
+which was rapidly spreading to all the German depot.</p>
+
+<p>"Well, it's worth being captured to think of the damage we've inflicted
+on the Huns this night," observed Jack, as he stood with Tom in the
+midst of their fellow prisoners.</p>
+
+<p>"That's right. We don't need to be ashamed of our work, especially as
+we've helped put the big guns out of business. I reckon the Boches won't
+treat us any too well, when they know what we've done."</p>
+
+<p>"And the other plane got away, they tell me," observed one of the French
+crew.</p>
+
+<p>"Yes, I saw her rise and light out for home, after dropping a ton or so
+of bombs on this district," said Tom. "Well, she can go back and report
+a success."</p>
+
+<p>"And let the folks know we're prisoners," said Jack. "It's tough luck,
+but it had to be, I suppose! We're lucky to be alive."</p>
+
+<p>"You said it," agreed Tom. "We came through a fierce fire, and it's a
+wonder that we weren't all shot to pieces. As it is, the plane is as
+good as ever."</p>
+
+<p>"Yes, and if we could only get out to it, and start it going we could
+escape," observed one of the Frenchmen bitterly. "There she is now, on
+as good a starting field as one could wish!"</p>
+
+<p>From their stockade of barbed wire they could look out and see, by the
+glare of the flames, that the great plane stood practically undamaged. A
+good landing had been made, but, unfortunately, in the midst of the
+German ammunition depot section.</p>
+
+<p>"Whew, that was a fierce one!" exclaimed Jack, as a loud explosion
+fairly shook the place where they were held prisoners. "Some ammunition
+went up that time."</p>
+
+<p>Indeed the explosion did seem to be a disastrous one, for there was
+considerable shouting and the delivering of orders in German following
+the blast. Many of the soldiers who had been summoned to stand on guard
+about the barbed-wire stockade, where the captured raiders were held,
+were summoned away, leaving only a small number on duty.</p>
+
+<p>But as these were well armed, and as the wire stockade was a strong one,
+and as Jack, Tom and the others had nothing with which to make a fight,
+they were as safely held as though guarded by a regiment.</p>
+
+<p>"There goes another!" cried Jack, as a second detonation, almost as loud
+as the first, shook the ground. "Some of our bombs must have been time
+ones."</p>
+
+<p>"No," said Tom. "What's probably happening is that the fire is reaching
+stores of ammunition, one after the other. This whole place may go up in
+a minute."</p>
+
+<p>That seemed to be the fear on the part of the Germans, for more orders
+were shouted, and all but two of the soldiers guarding the captives were
+summoned away from the wire stockade.</p>
+
+<p>There had been a bright flare of fire after the second explosion, but
+this soon died away, and the shouts and commands of the officers
+directing the fire-fighting force could be heard.</p>
+
+<p>Tom and Jack were standing near the wire barrier trying to look out to
+see what was going on beyond a group of ruined factory buildings, and at
+the same time casting longing eyes at the great aeroplane which seemed
+only waiting for them, when the two boys became aware of a figure which
+appeared to be slinking along the side of the stockade. This figure
+acted as though it desired to attract no attention, for it kept as much
+as possible in the shadows.</p>
+
+<p>"Did you see that?" asked Jack of his churn in a low voice.</p>
+
+<p>"Yes. What do you make it out to be?"</p>
+
+<p>"He isn't a German soldier, for he isn't in uniform. Have any of our
+crowd found a way out of this place by any chance?"</p>
+
+<p>"I don't know. If they have&mdash;"</p>
+
+<p>The boy's words were broken off by a low-voiced call from the slinking
+figure. It asked:</p>
+
+<p>"Are you American, French or English prisoners?"</p>
+
+<p>"Some of each variety," answered Jack, while at the sound of that voice
+Tom Raymond felt a thrill of hope.</p>
+
+<p>"If you get out, is there a chance for you to get away in your
+aircraft?" the figure in the shadow questioned. "Be careful, don't let
+the guards hear."</p>
+
+<p>"There are only two, and they're over at the front gate," said Jack, as
+Tom drew nearer in order better to hear the tones of that voice. "They
+seem more occupied in watching the fire than in looking at us," went on
+Jack.</p>
+
+<p>"Good!" exclaimed the man. "Now listen. I am an American, and I was
+captured by the Germans, through spy work, some time ago, in Paris. I
+was brought here, and they have been trying to force me to disclose the
+secret of some of my inventions.</p>
+
+<p>"I refused, and was sentenced to be shot to-morrow. But to-night you
+fortunately raided this place. My prison was one of the places to be
+blown up, and I managed to escape, without being hurt much. I heard that
+they had captured the crew of one of the airships, and I came to see if
+I could help. They don't know yet that I'm free, and I have two hand
+grenades.</p>
+
+<p>"Now listen carefully. I'll throw the grenades at the front gate. By
+shattering that it may be possible for you to get out. The two sentries,
+will have to take the chances of war. If you get out can you get away in
+your airship?"</p>
+
+<p>"Yes, and we can take you with us&mdash;Dad!" exclaimed Tom in a tense
+whisper.</p>
+
+<p>"Who speaks?" hoarsely asked the man in the shadow of the stockade.</p>
+
+<p>"It is I&mdash;your son&mdash;Tom Raymond! Oh, thank heaven I have found you at
+last!" exclaimed Tom, and he tried to stretch his hand through the
+barbed wire, but it was too close.</p>
+
+<p>"Is it really you, Tom, my boy?" asked Mr. Raymond in a broken voice,
+full of wonder.</p>
+
+<p>"Yes! And to think I should find you here, of all places!" whispered
+Tom. "I won't stop now to ask how it happened. Can you throw those
+grenades at the gate?"</p>
+
+<p>"I can, and will! Tell your friends to run back to the far end of the
+stockade to avoid being hurt. I can crouch down behind some of the
+ruined walls."</p>
+
+<p>Tom and Jack quickly communicated the good news to their friends, that a
+rescue was about to be attempted. It was a desperate chance, but they
+were in the mood for such.</p>
+
+<p>The two guards alone remaining of the force that had been posted about
+the stockade were so distracted by the fires and explosions around them,
+and so fearful of their own safety, that they did not pay much attention
+to the prisoners. So when Tom and Jack passed the word, and the airship
+crew ran to the end of the stockade and crouched down to avoid injury
+when the hand grenades should be exploded, the guards paid little
+attention.</p>
+
+<p>Mr. Raymond, for it was indeed he, crawled to a position of vantage, and
+then threw the hand grenades. They were fitted with short-time fuses,
+and almost as soon as they fell near the stockade gate they exploded
+with a loud report. A great hole was torn in the ground, and one of the
+sentries was killed while the other was so badly injured as to be
+incapable of giving an alarm. The gate was blown to pieces.</p>
+
+<p>"Come on!" cried Tom to his friends, as he saw what his father had done.
+"It's now or never, before they rush in on us."</p>
+
+<p>They raced to the breach in the wire wall of the stockade. Mr. Raymond,
+springing up from where he had taken refuge behind a pile of refuse, was
+there to greet those he had saved, and he and Tom clasped hands silently
+in the gloom that was lighted up by the fires and the bursts of light
+from the munition explosions.</p>
+
+<p>"Oh, Dad! And it's really you!" murmured Tom.</p>
+
+<p>"Yes, my boy! <i>I</i> never expected to see you again. Did you know I was
+here?"</p>
+
+<p>"I never dreamed of it! But don't let's stop to talk. We must get to the
+airship at once! But you are wounded, Dad!"</p>
+
+<p>"Nothing but a splinter from a bomb. It's only a cut on the head, Son,"
+and Mr. Raymond wiped away the blood that trickled down on his face.</p>
+
+<p>The newly freed prisoners lost no time. With a rush they made for the
+airship. If they could only get aboard and start it off all would yet be
+well. Could they do it?</p>
+
+<p>Momentary silence had followed the detonation of the two hand grenades
+thrown by Mr. Raymond, but now there came yells of rage from the
+Germans, disclosing that they had become aware of what was going on.</p>
+
+<p>"Lively, everybody!" cried Tom, as he led the way to the big plane.</p>
+
+<p>"Are we all here?" asked Jack.</p>
+
+<p>A rapid count showed that not one of the brave force had been left
+behind.</p>
+
+<p>"Is there room for me?" asked Mr. Raymond.</p>
+
+<p>"Well, I should say so!"</p>
+
+<p>"If there isn't I'll stay behind," cried Jack.</p>
+
+<p>"No you won't!" exclaimed Tom. "There'll be room all right!"</p>
+
+<p>The running men reached the plane just as they could see, in the light
+of the burning factories, a squad of Germans rushing to intercept them.
+In haste they scrambled aboard, and pressed the self-starter on the
+engine. There was a throbbing roar, answered by a burst of fire from the
+German rifles, for the place had been so devastated that no machine guns
+were available just then.</p>
+
+<p>"All aboard?" asked Tom, as he stood ready to put the motors at full
+speed and send the craft along the ground, and then up into the air.</p>
+
+<p>"All aboard&mdash;we're all here!" answered Jack, who had kept count. And Mr.
+Raymond was included.</p>
+
+<p>Then with a louder roar the motors jumped to greater speed, and the
+Italian plane started off. In another instant it rose into the air.</p>
+
+<p>With yells of rage the Germans even tried to hold it back with their
+hands, and, failing, they increased their fire. But though the plane was
+hit several times, and two on board shot, one later dying from his
+wounds, the whole party got off. A few minutes later they were above the
+burning factories, and had a view of the great destruction wrought on
+the German base. So completely destroyed was it that few defense guns
+were left in condition to fire at the aeroplane.</p>
+
+<p>"Well, we did that in great shape!" exclaimed Jack, as they were on
+their way over the Rhine again.</p>
+
+<p>"Couldn't have been better," conceded Tom. "And, best of all, we have
+dad with us."</p>
+
+<p>"How did it all happen?" asked Jack.</p>
+
+<p>"I don't know. We'll hear the story when we are safe in France."</p>
+
+<p>And safe they were as the gray morning broke. They arrived just as the
+crew of the other plane were relating, with sorrow, the fall of Tom,
+Jack and their comrades, and the rejoicing was great when it was known
+they were safe, and had not only outwitted the Huns, but had brought
+away a most important prisoner.</p>
+
+<p>"And now let's hear how it all happened," begged Major de Trouville,
+when the injured had been made as comfortable as possible. There were
+three of these, and one dead on the plane that returned first.</p>
+
+<p>The story of the attack on the German base was given in detail, and then
+Mr. Raymond took up the tale from the point where he had landed in
+Europe.</p>
+
+<p>He had started for Paris, just as he had written Tom, and had taken
+lodgings in the Rue Lafayette. He went out just before the starting of
+the bombardment by the big gun, and so escaped injury, but he fell into
+the hands of some German spies, who were on his trail, and who
+succeeded, after having drugged him, in getting him into Germany.</p>
+
+<p>The spies had succeeded in getting on the trail of a new invention Mr.
+Raymond had perfected, and which he had offered to the Allies. He had
+come to Paris on this business. The Huns demanded that he devote it to
+their interests, but he refused, and he had been held a prisoner over
+the Rhine, every sort of pressure being brought to bear on him to make
+him accede to the wishes of his captors.</p>
+
+<p>"But I refused," he said, "and they decided I should be shot. Whether
+this was bluff or not I don't know. But they never got a chance at me.
+In the night I heard, in my prison, the sound of explosions, and I soon
+realized what had happened. It was your bold airship raid, and one of
+the bombs burst my prison. I ran out and saw the Italian planes in the
+air.</p>
+
+<p>"What then happened you know better than I, but what you probably do not
+know is that you very likely owe your lives to a dispute that arose
+between the German infantry and the air squadron division," and he
+indicated Tom, Jack and the others who had been in the stockade.</p>
+
+<p>"How was that?" asked Jack.</p>
+
+<p>"The airmen claimed you as their prey, and the infantrymen said they
+were entitled to call you theirs. So, even in the midst of the fire and
+destruction, the commandant had to order you put in the stockade until
+he could decide whose prisoners you were. The infantrymen said they had
+captured you, but the airmen said their fire had brought down your
+plane."</p>
+
+<p>"Well, that was partly true," said Tom. "But it was an explosion from
+below that knocked us out temporarily. But we're all right now. And so
+are you, aren't you, Dad?"</p>
+
+<p>"Yes, but I worried a lot, not knowing what had happened to you, Tom,
+and being unable to guess what would happen to me. I was in the hands of
+clever and unscrupulous enemies. How clever they were you can judge when
+I tell you they took me right out of Paris. Perhaps the bombardment made
+it easier. But tell me&mdash;what of the big guns?"</p>
+
+<p>"Some of them are out of commission, thanks to your brave boy and his
+comrades," said Major de Trouville.</p>
+
+<p>"Good!" cried Mr. Raymond. "Some rumor to that effect sifted in to me
+there, but it seemed too good to be true. The Germans must be wild with
+rage."</p>
+
+<p>"I guess they are," admitted Jack.</p>
+
+<p>"And it would have gone hard with you if they had found you were the
+ones responsible," went on Tom's father. "As soon as I was out of my
+prison and saw the state of affairs, I managed to get the grenades, and
+I decided to rescue the airship men if I could. I never dreamed my own
+son would be among them, or that I might be brought away."</p>
+
+<p>And now it but remains to add that because of their exploits Tom and
+Jack received new honors at the hands of the grateful French, and,
+moreover, were promoted.</p>
+
+<p>Mr. Raymond, who had steadfastly refused to reveal the secret of his
+invention to the Huns, immediately turned it over to the Allies.</p>
+
+<p>Word of Mr. Raymond's safety and of the success of Tom and Jack was sent
+to those in Bridgeton, and that city had new reasons for being proud of
+her sons.</p>
+
+<p>But the war was not over, and the Germans might be expected to develop
+other forms of frightfulness besides the long-range guns, which, for the
+time being, were silenced. However, the destruction of the factories and
+ammunition stores by the raid over the Rhine was a blow that told
+heavily on the Hun.</p>
+
+<p>"Well, it seems there's another vacation coming to us," said Tom to Jack
+one morning, as they walked away from the breakfast table in their
+mess.</p>
+
+<p>"Yes? Well, I think we can use it. What do you say to a run into Paris
+to see your father? He's surely there now, and I'd like to have a talk
+with him."</p>
+
+<p>"With&mdash;<i>him?</i>" asked Tom, and there was a peculiar smile on his face.</p>
+
+<p>"Of course," said Jack.</p>
+
+<p>"Oh," was all Tom answered, but he laughed heartily.</p>
+
+<p>And so, with Tom and Jack on their way to Paris, for a brief respite
+from the war, we will take leave of them for a time. That they were
+destined to take a further part in the great struggle need not be
+doubted, for the Air Service boys were not the ones to quit until the
+world had been made a decent place in which to live.</p>
+
+<h3>THE END</h3>
+
+<hr style="width: 65%;" />
+<div class="footnote"><p><a name="Footnote_1_1" id="Footnote_1_1"></a><a href="#FNanchor_1_1"><span class="label">[1]</span></a> While of course this story is fiction, the description
+given above of the great guns and their method of firing and concealment
+is strictly in accord with the facts, and made from a sight of aeroplane
+photographs taken by the French, and from an official report, published
+April 26, 1918, by Deputy Charles Leboucq of the Department of the
+Seine.</p></div>
+
+
+
+
+
+
+
+<pre>
+
+
+
+
+
+End of the Project Gutenberg EBook of Air Service Boys Over The Rhine, by 
+Charles Amory Beach
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+</body>
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+Project Gutenberg's Air Service Boys Over The Rhine, by Charles Amory Beach
+
+This eBook is for the use of anyone anywhere at no cost and with
+almost no restrictions whatsoever.  You may copy it, give it away or
+re-use it under the terms of the Project Gutenberg License included
+with this eBook or online at www.gutenberg.org
+
+
+Title: Air Service Boys Over The Rhine
+       Fighting Above The Clouds
+
+Author: Charles Amory Beach
+
+Illustrator: Robert Gaston Herbert
+
+Release Date: October 3, 2010 [EBook #33834]
+
+Language: English
+
+Character set encoding: ASCII
+
+*** START OF THIS PROJECT GUTENBERG EBOOK AIR SERVICE BOYS OVER THE RHINE ***
+
+
+
+
+Produced by Bruce Albrecht, Mary Meehan and the Online
+Distributed Proofreading Team at http://www.pgdp.net
+
+
+
+
+
+
+
+
+
+                      AIR SERVICE BOYS OVER THE RHINE
+
+                       OR, FIGHTING ABOVE THE CLOUDS
+
+                           BY CHARLES AMORY BEACH
+
+            AUTHOR OF "AIR SERVICE BOYS FLYING FOR FRANCE,"
+            "AIR SERVICE BOYS OVER THE ENEMY'S LINES," ETC.
+
+
+    ILLUSTRATED BY
+    ROBERT GASTON HERBERT
+
+    THE SAALFIELD PUBLISHING CO.
+    AKRON, OHIO       NEW YORK
+
+    MADE IN U.S.A.
+
+    COPYRIGHT, 1919, BY
+    GEORGE SULLY & COMPANY
+
+
+[Illustration: BLOWING UP THE GERMAN MUNITION FACTORY.]
+
+
+
+
+CONTENTS
+
+
+I DOUBLE NEWS
+
+II ANXIOUS DAYS
+
+III ON TO PARIS
+
+IV SUSPICIONS
+
+V THE BOMBARDMENT OF PARIS
+
+VI THE RUE LAFAYETTE RUINS
+
+VII TOM'S FATHER
+
+VIII WHERE IS MR. RAYMOND?
+
+IX VARIOUS THEORIES
+
+X THE "DUD"
+
+XI A MONSTER CANNON
+
+XII FOR PERILOUS SERVICE
+
+XIII THE SPY
+
+XIV WITH COMRADES AGAIN
+
+XV THE PICKED SQUADRON
+
+XVI MISSING
+
+XVII SEEKING THE GUN
+
+XVIII A CLOUD BATTLE
+
+XIX QUEER LIGHTS
+
+XX THE BIG GUN
+
+XXI DEVASTATING FIRE
+
+XXII OVER THE RHINE
+
+XXIII OFF FOR GERMANY
+
+XXIV PRISONERS
+
+XXV THE ESCAPE
+
+
+
+
+AIR SERVICE BOYS OVER THE RHINE
+
+
+
+
+CHAPTER I
+
+DOUBLE NEWS
+
+
+"Here they come back, Tom!"
+
+"Yes, I see them coming. Can you count them yet? Don't tell me any of
+our boys are missing!" and the speaker, one of two young men, wearing
+the uniform of the Lafayette Escadrille, who were standing near the
+hangars of the aviation field "somewhere in France," gazed earnestly up
+toward the blue sky that was dotted with fleecy, white clouds.
+
+There were other dots also, dots which meant much to the trained eyes of
+Tom Raymond and Jack Parmly, for the dots increased in size, like
+oncoming birds. But they were not birds. Or rather, they were human
+birds.
+
+The specks in the sky were Caudrons. A small aerial fleet was returning
+from a night raid over the German ammunition dumps and troop centers,
+and the anxiety of the watching young men was as to whether or not all
+the airmen, among whom were numbered some of Uncle Sam's boys, had
+returned in safety. Too many times they did not--that is not all--for
+the Hun anti-aircraft guns found their marks with deadly precision at
+times.
+
+The Caudrons appeared larger as they neared the landing field, and Tom
+and Jack, raising their binoculars, scanned the ranks--for all the world
+like a flock of wild geese--to see if they could determine who of their
+friends, if any, were missing.
+
+"How do you make it, Tom?" asked Jack, after an anxious pause.
+
+"I'm not sure, but I can count only eight."
+
+"That's what I make it. And ten of 'em went out last night, didn't
+they?"
+
+"So I heard. And if only eight come back it means that at least four of
+our airmen have either been killed or captured."
+
+"One fate is almost as bad as the other, where you have to be captured
+by the Boches," murmured Jack. "They're just what their name
+indicates--beasts!"
+
+"You said something!" came heartily from Tom. "And yet, to the credit of
+airmen in general, let it be said that the German aviators treat their
+fellow, prisoners better than the Hun infantrymen do."
+
+"So I've heard. Well, here's hoping neither of us, nor any more of our
+friends, falls over the German lines. But look, Tom!" and Jack pointed
+excitedly. "Are my eyes seeing things, or is that another Caudron
+looming up there, the last in the line? Take a look and tell me. I don't
+want to hope too much, yet maybe we have lost only one, and not two."
+
+Tom changed the focus of his powerful glasses slightly and peered in the
+direction indicated by his chum. Then he remarked, with the binoculars
+still at his eyes:
+
+"Yes, that's another of our machines! But she's coming in slowly. Must
+have been hit a couple of times."
+
+"She's lucky, then, to get back at all. But let's go over and hear what
+the news is. I hope they blew up a lot of the Huns last night."
+
+"Same here!"
+
+The aircraft were near enough now for the throbbing of their big motors
+to be heard, and Tom and Jack, each an officer now because of gallant
+work, hurried across the landing field.
+
+It was early morning, and they had come, after a night's rest, to report
+for duty with others of the brave Americans who, during the neutrality
+of this country in the great conflict, went to France as individuals,
+some to serve as ambulance drivers, others to become aviators.
+
+The Caudron is the name given to one type of heavy French aeroplane
+carrying two or more persons and tons of explosive bombs.
+
+An air raid on the German lines by a fleet of these machines had been
+planned. It had been timed for an early hour of the night, but a mist
+coming up just as the squadron of heavy machines, each with two men and
+a ton or more of explosives, was ready to set out, the hour had been
+changed. So it was not until after midnight that the start had been
+made.
+
+And now the boys were coming back--that is all who were able to return.
+One machine was missing. At least, that was the assumption of Tom and
+Jack, for they could count but nine where there should have been ten.
+And of the nine one was coming back so slowly as to indicate trouble.
+
+One by one the machines, which ordinarily came back before daybreak,
+landed, and the pilot and the observer of each climbed clumsily down
+from their cramped seats. They were stiff with cold, in spite of the
+fur-lined garments they wore--garments that turned them, for the moment,
+into animated Teddy bears, or the likeness of Eskimos.
+
+Their faces were worn and haggard, for the strain of an airship bombing
+raid is terrific. But they were quiet and self-possessed as they walked
+stiffly across the field to make a report.
+
+"Any luck?" asked Tom, of one he knew; a Frenchman noted for his skill
+and daring.
+
+"The best, _mon ami_," he replied with a smile--a weary smile. "We gave
+Fritz a dose of bitter medicine last night."
+
+"And he gave us a little in return," sadly added his companion. "Quarre
+and Blas--" he shrugged his shoulders, and Tom and Jack knew what it
+meant.
+
+They were the men in the missing machine, the Caudron that had not come
+back.
+
+"Did you see what happened?" asked Jack.
+
+Picard, to whom Tom had first spoken, answered briefly.
+
+"They caught them full in the glare of a searchlight and let them have
+it. We saw them fall. There didn't seem to be any hope."
+
+"But the battery that did the firing--it is no more," added De Porry,
+the companion of Picard. "The bombs that Quarre and Blas carried went
+down like lead, right on top of the Hun guns. They are no more, those
+guns and those who served."
+
+"It was a retributive vengeance," murmured Picard.
+
+Then they passed on, and others, landing, also went to make their
+reports.
+
+Some of them had reached their objectives, and had dropped the bombs on
+the German positions in spite of the withering fire poured upward at
+them. Others had failed. There is always a certain percentage of
+failures in a night bombing raid. And some were unable to say with
+certainty what damage they had caused.
+
+The last slowly flying machine came to a landing finally, and there was
+a rush on the part of the other aviators to see what had happened. When
+Tom and Jack saw a limp form being lifted out, and heard murmurs of
+admiration for the pilot who had brought his machine back with a
+crippled engine, they realized what had happened.
+
+The two brave men had fulfilled their mission; they had released their
+bombs over an important German factory, and had the terrible
+satisfaction of seeing it go up in flames. But on their return they had
+been caught in a cross fire, and the observer, who was making his first
+trip of this kind, had been instantly killed.
+
+The engine had been damaged, and the pilot slightly wounded, but he had
+stuck to his controls and had brought the machine back.
+
+There was a little cheer for him, and a silent prayer for his brave
+companion, and then the night men, having made their reports, and having
+divested themselves of their fur garments, went to rest.
+
+"Well, what's on the programme for to-day, Tom?" asked Jack, as they
+turned back toward the hangars where they had their headquarters with
+others of their companions in the Lafayette Escadrille and with some of
+the French birdmen.
+
+"I don't know what they have on for us. We'll have to wait until the
+orders come in. I was wondering if we would have time to go and see if
+there's any mail for us."
+
+"I think so. Let's go ask the captain."
+
+They had, of course, reported officially when they came on duty, and now
+they went again to their commanding officer, to ask if they might go a
+short distance to the rear, where an improvised post-office had been set
+up for the flying men.
+
+"Certainly, messieurs," replied the French captain, when Tom proffered
+the request for himself and his chum. "Go, by all means." He spoke in
+French, a good mastery of which had been acquired by our heroes since
+their advent into the great war. "Your orders have not yet arrived, but
+hold yourselves in readiness. Fritz is doubtless smarting under the dose
+we gave him last night, and he may retaliate. There is a rumor that we
+may go after some of his sausages, and I may need you for that."
+
+"Does he mean our rations have gone short, and that we'll have to go
+collecting bolognas?" innocently asked a young American, who had lately
+joined.
+
+"No," laughed Tom. "We call the German observation balloons 'sausages.'
+And sometimes, when they send up too many of them, to get observations
+and spoil our plans for an offensive, we raid them. It's difficult work,
+for we have to take them unawares or they'll haul them down. We
+generally go in a double squadron for this work. The heavy Caudrons
+screen the movements of the little Nieuports, and these latter, each
+with a single man in it, fire phosphorus bullets at the gas bags of the
+German sausages.
+
+"These phosphorus bullets get red hot from the friction of the air, and
+set the gas envelope aglow. That starts the hydrogen gas to going
+and--good-night to Mr. Fritz unless he can drop in his parachute. A raid
+on the sausages is full of excitement, but it means a lot of
+preparation, for if there has any rain or dew fallen in the night the
+gas bags will be so damp that they can't be set on fire, and the raid is
+off."
+
+"Say, you know a lot about this business, don't you?" asked the young
+fellow who had put the question.
+
+"Nobody knows a _lot_ about it," replied Jack. "Just as soon as he does
+he gets killed, or something happens to him. We're just learning--that's
+all."
+
+"Well, I wish I knew as much," observed the other enviously.
+
+Tom and Jack walked on toward the post-office, being in rather a hurry
+to see if there was any mail for them, and to get back to their stations
+in case their services were needed.
+
+As they went along they were greeted by friends, of whom they had many,
+for they had made names for themselves, 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 energy that Tom asked:
+
+"What's the matter? Haven't you heard from Bessie lately?"
+
+"Oh--that!" murmured Jack, but Tom noticed that his friend blushed under
+his coat of tan. "Go on," Jack said, a moment later, "tell me about your
+father. Is the French government going to give him a big order for his
+stabilizer, now that we got that paper away from that sneak of a
+Tuessig?"
+
+"Well, I guess dad's trip here has something to do with his aeroplane
+device, but he hints in his letter about something else. He said he
+didn't want to write too much for fear a spy might get hold of the
+information. But you know my father is an expert on ordnance matters and
+big guns, as well as in other lines of fighting."
+
+"That's so, Tom. He certainly is a wonder when it comes to inventing
+things. But what do you suppose his new mission is?"
+
+"I can't quite guess. But it is for the service of the Allies."
+
+"And you say he's on his way to Paris now?"
+
+"He ought to be there by this time," Tom answered. "I'm going to see if
+I can't get permission to send a message through, and have an answer
+from dad. Maybe he might get out here to see us."
+
+"Or we could go in and meet him."
+
+"Not for a week. You know we just came back from leave, and we won't be
+over our tour of duty for seven days more. But I can't wait that long
+without some word. I'm going to see what I can find out."
+
+Tom and Jack, like all the other American fliers, were in high favor
+with the French officers. In fact every aviator of the Allied nations,
+no matter how humble his rank, is treated by his superiors almost as an
+equal. There is not that line of demarcation noticed in other branches
+of the service. To be an aviator places one, especially in England and
+France, in a special class. All regard him as a hero who is taking
+terrible risks for the safety of the other fighters.
+
+So Tom readily received permission to send a message to the hotel in
+Paris mentioned by his father as the place where Mr. Raymond would stay.
+And then Tom had nothing to do but wait for an answer.
+
+Nothing to do? No, there was plenty. Both Tom and Jack had to hold
+themselves in readiness for instant service. They might be sent out on a
+bombing expedition at night in the big heavy machines, slow of flight
+but comparatively safe from attack by other aircraft.
+
+They might have the coveted honor of being selected to go out in the
+swift, single Nieuports to engage in combat with some Hun flier. To
+become an "ace"--that is a birdman who, flying alone, has disposed of
+five enemies--is the highest desire of an aviator.
+
+Tom and Jack, eager and ambitious, were hoping for this.
+
+Again, in the course of the day's work, they might be selected to go up
+in the big bi-motored Caudrons for reconnoissance work. This is
+dangerous and hard. The machines carry a wireless apparatus, over which
+word is sent back to headquarters concerning what may be observed of the
+enemy's defenses, or a possible offensive.
+
+Often the machines go beyond the range of their necessarily limited
+wireless, and have to send back messages by carrier pigeons which are
+carried on the craft.
+
+By far the most dangerous work, however, is that of "_relage_" or fire
+control. This means that two men go up in a big machine that carries a
+large equipment. Their craft is heavy and unwieldy, and has such a
+spread of wing surface that it is not easily turned, and if attacked by
+a German Fokker has little chance of escape. A machine gun is carried
+for defense.
+
+It is a function of those in the machine to send word back to the
+battery officers of the effect of the shots they are firing, that the
+elevation and range may be corrected. And those who go out on "_relage_"
+work are in danger not only from the fire of the enemy's batteries, but
+often, also, from their own.
+
+Tom and Jack had their share of danger and glory during the week they
+were on duty following the receipt of the two pieces of news. They went
+up together and alone, and once, coming back from a successful trip over
+the enemy's lines, Tom's machine was struck by several missiles. His
+cheek was cut by one, and his metal stability control was severed so
+that his craft started to plunge.
+
+Tom thought it was his end, but he grasped the broken parts of the
+control rod in one hand, and steered with the other, bringing his
+machine down behind his own lines, amid the cheers of his comrades.
+
+"And I'm glad to be back, not only for my sake, but for the sake of the
+machine. She's a beauty, and I'd have hated like anything to set fire to
+her," remarked Tom, after his wound had been dressed.
+
+He referred to the universal practice of all aviators of setting fire to
+their craft if they are brought down within the enemy lines, and are not
+so badly injured as to prevent them from opening the gasoline tank and
+setting a match to it. This is done to prevent the machine, and often
+the valuable papers or photographs carried, from falling into the hands
+of the enemy.
+
+The end of the week came, the last of seven anxious days, and it was
+time for Tom and Jack to be relieved for a rest period. And the days had
+been anxious because Tom had not heard from his father.
+
+"I hope the vessel he was coming on wasn't torpedoed," said Tom to his
+chum. "He's had more than time to get here and send me some word. None
+has come. Jack, I'm worried!" And Tom certainly looked it.
+
+
+
+
+CHAPTER III
+
+ON TO PARIS
+
+
+Those were the days--and they had been preceded by many such--when
+travel across the Atlantic was attended with great risk and uncertainty.
+No one knew when a lurking German submarine might loose a torpedo at a
+ship carrying men, women and children. Many brave and innocent people
+had found watery graves, and perhaps suffered first a ruthless fire from
+the German machine guns, which were even turned on lifeboats! So it was
+no wonder that Tom Raymond was worried about his father.
+
+"It's queer we can't get any word from the authorities in Paris,"
+remarked Jack, as he and his chum were speculating one day on what might
+have happened.
+
+"Yes, and that helps to bother me," Tom admitted. "It isn't as if they
+weren't trying, for the officers here have done all they can. They've
+gotten off my messages, but they say there is no reply to them."
+
+"Then it must mean that your father, if he is in Paris, hasn't received
+them."
+
+"Either that, Jack; or else he doesn't dare reply."
+
+"Why wouldn't he dare to, Tom?"
+
+"Well, I don't know that I can give a good reason. It might be that he
+is on such a secret mission that he doesn't want even to hint about it.
+And yet I can't understand why he doesn't send me at least a message
+that he has arrived safely."
+
+As Tom said this he looked at his chum. The same thought was in the mind
+of each one:
+
+Had Mr. Raymond arrived safely?
+
+That was what stirred Tom's heart. He knew the danger he and Jack had
+run, coming across to do their part in flying for France, and he well
+realized that the Germans might have been more successful in attacking
+the vessel on which his father had sailed, than they had the one which
+had carried Tom and Jack.
+
+"Well, what are we going to do?" asked Jack of his chum. "You know we
+arranged, when we should get our leave, to go back to that pretty little
+French village, which seemed so peaceful after all the noise of battle
+and the roar of the aeroplane engines."
+
+"Yes, I know we planned that," said Tom, reflectively. "But, somehow, I
+feel that I ought to stay here."
+
+"And not take our relief?"
+
+"Oh, no. We'll take that," decided Tom. "We must, in justice to
+ourselves, and those we work with. You know they tell us an airman must
+always be at his best, with muscles and nerves all working together. And
+a certain amount of rest and change are necessary, after a week or so of
+steady flying. So we'll take our rest in order to be in all the better
+shape to trim the Fritzies. But I was thinking of staying right here."
+
+"And not go back into the country?" asked Jack.
+
+Tom shook his head.
+
+"I'd like to stay right here until I get word from my father," he said.
+"He may send a message at any time, and he knows I am stationed here. Of
+course I could send him word that we're having a little vacation, and
+give him our new address.
+
+"But the mails are so mixed up, and the telegraph and telephone systems
+are so rushed, that he might not get it. So I think the best thing will
+be to stay right here where I'll be on hand to get it the moment word
+comes. But don't let me keep you, Jack. You can go, if you want to."
+
+"Say, what do you think I am?" cried his chum. "Where you stick, I
+stick! We'll both wait here for word from your father. I have a sort of
+feeling that he is all right."
+
+"Well, to tell you the truth, I suppose he is. But, at the same time,
+I'm worried. I can't explain it, but I have a sort of sense that he is
+in danger."
+
+"Not if he is in Paris, Tom. The German's haven't gotten within striking
+distance of that city yet, in spite of their boasts--the boasts of the
+Kaiser and of the Crown Prince."
+
+"No, if dad were in Paris I'd feel that he was comparatively safe. But
+first I want to know that he is. And yet, even if he has put up at that
+house in the Rue Lafayette, where he said in his letter he'd stay, there
+may be some danger."
+
+"Danger in Paris? What do you mean, Tom?"
+
+"Well, Paris has been bombed from the air, you know."
+
+"True, Tom. But, say! we've almost come to disregard such mild things as
+that from the Huns, haven't we?"
+
+"Well, we'll just stay right on here," decided Tom. "I don't mean to say
+that we'll stay around our hangar all the while, but we'll keep in
+touch, throughout the day, with the communication headquarters. Dad may
+send a message at any time, and I want to get it as soon as it arrives."
+
+Jack could understand his chum's feelings, and so the Air Service boys,
+who, some time previous, had sought and received permission to go back
+several kilometers into the country for a rest, announced that they
+would stay on at the aerodrome.
+
+Nor did they lack excitement. The place where they were stationed was a
+busy one. For every twenty pilots and observers there are detailed about
+one hundred men as helpers. There are cooks, photographers, mechanics of
+various sorts, telephone, telegraph and wireless operators, orderlies
+and servants.
+
+Of these Tom and Jack had their share, for it is the business of an
+airman to fly and fight, and he does nothing except in that line. He is
+catered to and helped in every possible way when not in the air. He has
+some one to wait on him, to look after his machine, and to attend to his
+hurts, if he is unlucky enough to get any. Of course each flier goes
+over, personally, his own craft, but he has oilers and mechanics to do
+all the detail work.
+
+"Well, there they go!" exclaimed Tom to Jack one morning, the second of
+their "vacation," as they observed a number of "aces" about to go up
+and search above the clouds for some Hun to attack.
+
+"Yes, and I wish I was with them!" said Jack.
+
+"Waiting isn't much fun," agreed his chum. "I'm sure I can't understand
+why dad doesn't send some word. If this keeps up much longer--Say, Jack,
+look at Parla!" he suddenly cried. "What's the matter with him?"
+
+Jack looked. The men, in their machines, had started off to get momentum
+for a rise into the air. But there had been a rain and the ground was
+soft, which kept down the speed. All the pilots seemed to get off in
+fairly good shape except one, Parla by name, who had only recently
+secured the coveted designation of "ace."
+
+And then occurred one of those tragedies of flying. Whether he was
+nervous at taking a flight in such distinguished company, or whether
+something went wrong with Parla's machine never would be known.
+
+He was the last in the line, and as it was rather misty he might have
+been anxious not to lose sight of his companions. He did not take a long
+enough run, and when he reached the end of the field he was not high
+enough to clear the line of hangars that were in front of him.
+
+Some one shouted at him, not stopping to realize that the noise of the
+motor drowned everything else in the ears of the pilot.
+
+The luckless man tried to make a sharp turn, to get out of danger. One
+of his wing tips caught on the canvas tent, or hangar, and in another
+instant there was a crash and a mass of wreckage. From this, a little
+later, poor Parla was carried.
+
+But the others did not stay, for though the shadow of death hovered over
+the Escadrille, the business of war went on.
+
+After three days Tom and Jack could not stand it any longer. They begged
+for permission to go up into the air. It was granted, though officially
+they were still on leave. Ascending together in a Caudron, on a
+photographing assignment, they were attacked by two swift German
+Fokkers.
+
+Tom worked the gun, and to such good effect that he smashed one machine,
+sending it down with a crash, and drove the second off. So other laurels
+were added to those the boys already had.
+
+"If this keeps on we'll be soon wearing the chevrons of sergeants," said
+Jack, as they landed.
+
+"Well, I'd almost give up hope of them to hear from dad," announced
+Tom. "I'm going to see if some word hasn't come."
+
+But there was no message. Still the strange silence continued, and Tom
+and his chum did not know whether Mr. Raymond had reached Paris or not.
+Through his own captain, Tom appealed to the highest authority at the
+Escadrille, asking that a last imploring message be sent to the address
+in the Rue Lafayette.
+
+This was done, and then followed another day of waiting. At last Tom
+said:
+
+"Jack, I can't stand it any longer! This suspense is fierce!"
+
+"But what are you going to do about it?"
+
+"I'm going to Paris! That's what! We'll go there and find my father if
+he has arrived. If he hasn't--well, there is still some hope."
+
+"Go to Paris!" murmured Jack.
+
+"Yes. It's the only place where I can make uncertainty a certainty. Come
+on, we'll go to Paris!"
+
+
+
+
+CHAPTER IV
+
+SUSPICIONS
+
+
+Tom Raymond started across the field toward headquarters. Jack followed,
+but there was a strange look on the latter's face.
+
+"I don't see how you're going to Paris," remarked Jack, at length. "Do
+you mean we're to go in separate machines, or together?"
+
+"Oh, nothing like that!" exclaimed Tom. "We won't go in machines at all.
+We'll go by train, if we can get one, or by motor."
+
+"But you're heading for the Escadrille Headquarters office, and--"
+
+"We've got to get official permission to go," explained Tom. "We can't
+rush off, whenever we like, as we used to go fishing together."
+
+To his captain Tom explained matters more fully than he had done before.
+In effect he related the fact of having received the letter, stating
+that Mr. Raymond had started for Paris, presumably to engage in some
+work for the French government, or at least for the Allies. Whether he
+had arrived or not, and, in the former case, to ascertain why he had
+not sent some word to his son, was the object of Tom's quest.
+
+"I've tried and tried, from this end, to get in touch with him,"
+explained Tom; "but something seems to happen to my messages. I know
+they leave here all right, but after that they are lost. Now I have an
+idea that there is so much going on in Paris--so much necessary war
+work--that the ordinary lines of communication are choked. But if I
+could go to the capital in person I could soon find out whether my
+father was at the address he gave."
+
+"And you want, do you, to go together?" asked the kindly French captain,
+smiling at Tom and Jack.
+
+"We'd like to go," said Tom.
+
+"And go you shall. I will write the necessary order. You have done well,
+and I understand you have some days of leave coming. To them I shall add
+more. But come back to me," he added, as he filled out the pass form.
+"Come back. We need you Americans now more than ever!"
+
+"We'll come back," promised Tom. "All I want to go to Paris for is to
+find out about my father."
+
+"Ah, I envy you," said the captain softly. "Both in the possession of a
+father, who must be proud to have such a son as you, and also because
+you are going to Paris. It is the most beautiful--the most
+wonderful--city in the world. And to think--to think that those
+barbarians would sack her! Ah, it is terrible!" and with a sad nodding
+of his head, following the shaking of an avenging fist toward the German
+lines, he waved Tom and Jack an adieu.
+
+The two Air Service boys lost little time in making their preparations
+to leave for the French capital. They had to get certain passes and
+papers, and they wished to say good-bye to some of their comrades in
+arms. For, more than any other branch of the service, is aviation
+uncertain as to life or death. Tom and Jack well knew that some, perhaps
+many, of those who wished them "_au revoir_," and "_bonne chance_,"
+would not be alive when they returned. And Tom and Jack might not return
+themselves. True, their chances were comparatively good, but the
+fortunes of war are uncertain.
+
+And so, after certain preliminaries, Tom and Jack, their pet machines in
+the hangars, left behind their beloved comrades and were taken by motor
+to the nearest railway station. There they secured their tickets and
+took their places to wait, with what patience they could, their arrival
+in Paris.
+
+The train was well filled with "_permissionnaires_," or soldiers on
+leave for a few days of happiness in the capital, and at certain
+stations, where more got on, the rush was not unlike that at a crowded
+hour in some big city.
+
+"I see something good," remarked Jack, as they sat looking out at the
+scenery, glad, even for a brief moment, to be beyond the horrors of war.
+
+"What?" asked his companion.
+
+"There's a dining-car on this train. We sha'n't starve."
+
+"Good enough, I almost forgot about eating," said Tom. "Now that you
+speak of it, I find I have an appetite."
+
+They ate and felt better; and it was as they were about to leave the
+dining-car to go back to their places, that Jack nudged Tom and
+whispered to him:
+
+"Did you hear what he said?"
+
+"Hear what who said?"
+
+"That man just back of you. Did you have a good look at him?"
+
+"I didn't, but I will have," said Tom, and, waiting a moment so as not
+to cause any suspicion that his act was directed by his chum, Tom turned
+and looked at the person Jack indicated. He beheld a quietly dressed
+man, who seemed to be alone and paying attention to no one, eating his
+lunch.
+
+"Well, what about him?" asked Tom. "I don't see anything remarkable
+about him, except that he's a slow eater. I admit I bolt my food too
+much."
+
+"No, it isn't that," said Jack in a low voice. "But don't you think he
+looks like a German?"
+
+Tom took another casual glance.
+
+"Well, you might find a resemblance if you tried hard," he answered.
+"But I should be more inclined to call him a Dutchman. And when I say
+Dutchman I mean a Hollander."
+
+"I understand," remarked Jack. "But I don't agree with you in thinking
+that he may be from Holland. Of course men of that nationality have a
+right to go and come as they choose, where they can, but I don't believe
+this chap is one."
+
+"Why not?"
+
+"Because I heard him mutter something in German."
+
+"Well, lots of Hollanders can speak German, I have no doubt. I can
+splutter a few words myself, but not enough to hurt me. I began to pick
+up some from the prisoners, after we had that experience with Potzfeldt,
+when we realized that even a little knowledge of the Hun's talk, much as
+we hate him, would be of service. And so you think you heard this fellow
+speak German?" asked Tom, as he pretended to tie his shoe lace, to make
+an excuse for pausing.
+
+"I'm sure I did," said Jack.
+
+"What did he say?"
+
+"Something about wishing he had a plate of _metzel suppe_. Of course I
+don't guarantee that pronunciation, but--"
+
+"Oh, it'll do," said Tom, graciously. "Well, there's nothing very
+suspicious in that, though. I might wish for some _wienerwurst_, but
+that wouldn't make me a German spy."
+
+"No. But take one other thing and you'll have to admit that there is
+some ground for my belief."
+
+"What's the other thing, old top?" asked Tom, in imitation of some
+Englishmen.
+
+"He was making drawings of the railroad line," asserted Jack.
+
+"How do you know?"
+
+"I saw him. He pretended to be looking at the _carte de jour_, and I
+caught a glimpse of a sheet of paper on which he was making certain
+marks. I'm sure he was sketching out something about the railroad, for
+use, maybe, in a future air raid."
+
+"Nonsense!" exclaimed Tom. "As a matter of fact, I don't doubt that the
+German secret agents know every foot of ground in and about Paris. They
+must have maps of this railroad the same as the French have of some of
+Germany's, only you've got to hand it to the Huns! They certainly went
+into this thing well prepared the more discredit to us, in a way. But
+are you sure of what you say, Jack?" he added, after a moment's thought.
+
+"Positive! I'm sure that man is a German spy, masking as a Hollander or
+possibly a Swiss. He's sighing for some of his country's good
+cooking--though that's one of the few good things about it--and he's
+making some sort of a map."
+
+Tom thought over the matter a moment. The man did not appear to notice
+the two chums.
+
+"I'll tell you what we can do," Tom said. "We'll soon be in at the Gare
+de l'Est, and we can tip off some of the officers around there. They can
+follow this fellow, if they think it's worth while."
+
+"Well, I think it's worth while," said Jack. "If that fellow isn't a spy
+I'm a Dutchman!"
+
+As Jack spoke the man looked up and full at the two lads, almost as if
+he had heard the words.
+
+
+
+
+CHAPTER V
+
+THE BOMBARDMENT OF PARIS
+
+
+"There, Jack! what did I tell you? I win! You lose, and it's me for a
+fine dinner at your expense! You lose! Do you hear?"
+
+Tom Raymond, with a hearty laugh, clapped his chum on the shoulder, and
+seemed mirthfully excited over something. As for Jack Parmly he looked
+first at his chuckling comrade and then at the man he suspected of being
+a German spy. The latter, who had glanced keenly at the boys, with
+something akin to anger on his face, now was plainly puzzled.
+
+"Do you understand?" demanded Tom in a loud voice, which attracted the
+attention of many in the car. But a look at the two, showing them to be
+Americans and, therefore, to the French mind, capable of any
+eccentricity, seemed to make matters right. Most of the diners resumed
+their meals.
+
+"See what I mean, Jack?" went on Tom. "You lose! Understand?"
+
+"No, I don't understand," was the low-voiced and somewhat puzzled
+answer.
+
+"Then for the sake of your gasolene tank _pretend_ that you do!"
+fiercely whispered Tom in his chum's ear. "Play up to my game! Don't you
+see that fellow's suspicious of us? He thinks we've been talking about
+him. I win, do you understand?"
+
+"Oh, yes," answered Jack, and then, in a louder tone, intended to allay
+suspicion on the part of the suspect, he added: "You win all right, Tom!
+I'll buy the dinner. I didn't think the train would get in so soon! It's
+one on me all right!"
+
+And then, laughing and talking in seeming carelessness, as though they
+had not a thought in the world but the friendly wager they had made,
+they went back to their coach.
+
+"That was a narrow squeak," observed Tom. "He was getting suspicious all
+right, and in another moment might have made an indignant demand of the
+guard that we cease observing him. It might have made trouble for us.
+We're not members of the secret police, remember."
+
+"Well," remarked Jack, "he might have made trouble for us, but I could
+do the same for him. I'd let fall a hint about the map of the railway he
+was sketching."
+
+"You mean all right, Jack, but I don't believe your plan would work. If
+that fellow really is a German spy, which I doubt, he'd destroy the
+map, if he made one, the moment he thought himself in danger."
+
+"Maybe you're right, Tom," agreed his chum, a bit dubiously. "But I
+certainly think there is something wrong about that man."
+
+"Maybe you think he is Carl Potzfeldt, disguised, Jack."
+
+"No, nothing like that. Though I wouldn't be surprised if he happened to
+be friendly with that sneaking spy. And, speaking of Potzfeldt, Tom,
+though he isn't by any means a pleasant subject, do you know we are soon
+to be in Paris where--"
+
+"Where Bessie and her mother are, you mean. You're right, old chap, I
+haven't forgotten that, and I'll wager one chance for promotion that you
+haven't forgotten it either."
+
+Jack's blush was sufficient answer to his friend.
+
+"I couldn't quite understand what you meant, Tom, by talking so suddenly
+and loudly about you winning and me losing," went on Jack, as they got
+their baggage ready, for the train was about to enter the Paris station.
+
+"That was camouflage, Jack, pure and unadulterated camouflage," answered
+Tom with a laugh. "I had to do something in a hurry to get that fellow's
+gaze off us, or he might have made a scene, and we don't want that. But
+if I had made a wager with you about the time, I'd have won, for here
+we are, right on the dot, which is unusual in these days, I believe."
+
+"You said something, Tom. But what are we going to do about our spy?"
+
+"Well, if you insist that's what he is, I think the best thing would be
+to notify some secret service official. There must be plenty of them
+around the station. Every passenger, before he leaves the station, has
+to have his papers stamped by the military authorities. Then's your
+chance to tip them off about this chap."
+
+"I'll do it, Tom. I'm not going to lose any chances of putting German
+enemies out of the way."
+
+It was about five o'clock when the train pulled into the Gare de l'Est,
+and the passengers, including many soldiers on leave, prepared for the
+joys of Paris. Tom and Jack, proceeding as did the others to the place
+designated for the official stamping of papers, found a chance to tell
+their suspicions to an officer, and to point out the man Jack suspected.
+
+"The matter shall be attended to," said the military official, treating
+the information with the utmost respect, and evidently considering it of
+more importance than Tom imagined would be attached to it. "We are
+greatly indebted to you, not only because you are of our beloved
+aviators, but because you also think to do this for France--to protect
+her from enemies within as well as from those who are without. France
+thanks you, gentlemen!" and the aged officer saluted the two young men
+as though he considered them his equals.
+
+"Well, now that's off our minds we can get down to the real business
+that brought us to Paris," suggested Tom. "And that's to find my
+father--if he's here. After that we can look up Bessie and her mother,
+if you like, Jack."
+
+"Of course I'll be glad to do that, Tom, and I should think that you--"
+
+"Oh, of a surety, yes, as a Frenchman would say. I'll be happy also, to
+see our friends again, but I know Bessie will consider--"
+
+"Oh, drop it, will you?" begged Jack, for he could see that his chum was
+about to start to rally him about the girl.
+
+"Then," went on Tom, "the first thing to do, in my opinion, is to get to
+this address in the Rue Lafayette where dad said he would make his
+headquarters, and see why he hasn't answered any of my messages. When I
+once see him, and know he's all right, I'll feel better."
+
+"Even capable of eating that dinner you claim to have won from me?"
+asked Jack.
+
+"Of course."
+
+The two Air Service boys had the satisfaction of seeing the "tip" they
+gave acted on, for as they left the station they observed the officer
+to whom they had reported, detailing a man in plain clothes, evidently
+one of the secret police, to follow the man they had watched in the
+dining car.
+
+"We can leave the rest to the military," said Tom. "And now let's get to
+where we're going."
+
+"Hadn't we better arrange for hotel accommodations, or to stop at a
+pension?" asked Jack. "You know Paris is crowded now, even in war times,
+and we've got to stay here all night, even if we learn that your father
+hasn't yet arrived."
+
+"That's so," agreed Tom. "Maybe we had better get a place to bunk
+first."
+
+It would not have been an easy task had they not worn the uniforms of
+aviators. But once these were noted, they were welcomed with smiles, and
+though at the first place they applied there was no room, the proprietor
+busied himself to such advantage that the boys were soon settled in a
+big double room with a fine view of a busy section of Paris.
+
+On every side was seen evidence of the joy and satisfaction felt at the
+showing made by the progress of the United States in her war programme.
+
+The stars and stripes were seen floating from many staffs, mingled with
+the tricolor of France and the English union jack. That Uncle Sam had
+at last gotten beyond the bounds of patience with a ruthless and
+sneaking enemy and was making energetic warfare against him was welcome
+news to those who had so long borne the unequal brunt of battle.
+
+"Americans? Ah, everything that I have is yours!" the hotel proprietor
+told Tom and Jack. "You have but to ask. And now come, I will show you
+the way to the cellar."
+
+"But we don't care to see the cellar," remarked Tom in wonder. "No doubt
+it is a very fine one, monsieur," he added in his best French, which was
+nothing to boast of. "No doubt it is most excellent, but we don't care
+for cellars."
+
+"Ah, I know, but it is for protection in case of an air raid that I show
+it to you. It is there we all take shelter. There have been raids, and
+there will be more. It is well to be prepared. It is a well-protected
+cellar."
+
+"Oh, well, that's different," observed Jack. "Come on, Tom, we'd better
+learn the best and quickest route to the basement. No telling when we
+might want to use it."
+
+They descended with the proprietor and saw that he had arranged the
+cellar with a false roof of beams, on top of which were sand bags. In
+case a bomb was dropped on the hotel or in its vicinity the cellar would
+offer almost certain protection.
+
+The boys arranged for a stay of at least a week in Paris, having told
+the proprietor their errand to the capital. By the time they had
+finished their dinner they found it was too late to set out in search of
+Mr. Raymond, as in the changed, war-time Paris little could be done in
+the evening. So Tom and Jack retired to their room and their bed.
+
+"Are you going right to the Rue Lafayette?" asked Jack of his chum, the
+next day.
+
+"Yes, and if we can't get any news of him there we'll appeal to the
+military authorities. I have a letter of introduction to persons high in
+authority from our captain."
+
+The boys hailed a taxicab and gave the chauffeur the necessary
+directions. They were bowling along through the beautiful streets of
+Paris, noting on all sides the warlike scenes, and their thoughts were
+busily occupied, when they suddenly became aware that something had
+happened.
+
+Like a thunderbolt from a clear sky there sounded a terrific explosion,
+and at no great distance. The concussion shook the ground, and they
+could feel the taxicab tremble under the shock, while the chauffeur
+instantly threw on all brakes, making the machine skid dangerously.
+
+"What is it? What's the matter?" yelled Jack.
+
+"Airship raid most likely!" shouted Tom. "Boches are dropping bombs on
+Paris! Oh, where's our cellar, Jack?"
+
+The taxicab driver jumped down and opened the door.
+
+"You had best alight, gentlemen," he said. "You must seek shelter."
+
+"Is it an airship raid?" asked Tom.
+
+"No, there is not an airship in sight. No such alarm has been sounded by
+the police. I fear the bombardment of Paris by the Germans has begun!"
+
+
+
+
+CHAPTER VI
+
+THE RUE LAFAYETTE RUINS
+
+
+Tom Raymond and Jack Parmly alighted from the taxicab more quickly than
+they had gotten in. The chauffeur was anxiously scanning the sky.
+Excited men, women and children were rushing about, and yet it was not
+such excitement as might be caused by the first shelling of the
+beautiful city. It was more, as Tom said afterward, as though the
+populace had been taken by surprise by a new method in the same kind of
+warfare, for an occasional German Zeppelin or a bombing aircraft had,
+before this, dropped explosives. To these the French had become as much
+accustomed as one ever can to such terrible means of attack.
+
+But this was different. There was no sign of a Hun aircraft, and, as the
+chauffeur had said, no police warning had been sounded.
+
+"What is it?" asked Jack.
+
+"It is a bombardment, that is all I know," replied the taxicab driver.
+He spoke in French, a language which the two boys used fairly well,
+though, as has been said, their accent left much to be desired.
+
+"You had best seek shelter until it is over," went on the man. "I shall
+do so myself." He seemed to pause suggestively, and Jack handed him some
+money.
+
+"_Merci_," he murmured, and an instant later was careening down the
+street at full speed.
+
+"He isn't losing any time," said Jack.
+
+"No. And perhaps we hadn't better, either. Where'd that shell fall?"
+asked Tom.
+
+"I don't know, but it must have been somewhere about here, judging by
+the noise. Look, the crowd's over that way," and he pointed to the left.
+
+It was true. Careless of the danger of remaining in the open, men, and
+women, too, as well as some children, were rushing toward the place
+where, undoubtedly, the shell from the German gun had fallen.
+
+"Might as well take it in," suggested Jack. "I don't want to crawl down
+into a cellar or a subway quite yet, even if there's one around here; do
+you?"
+
+"No," answered Tom, "I don't. Go on, I'm with you."
+
+They followed the throng, but could not resist the impulse to gaze
+upward now and then for a possible sight of another shell, which, they
+half hoped, they might observe in time to run for shelter. But of course
+that would have been out of the question. However, quiet succeeded the
+din of the explosion, which had been close to the spot where the taxicab
+had stopped and the boys had alighted.
+
+Following the crowd, Tom and Jack came to a side street, and one look
+down it showed the havoc wrought by the German engine of death. The
+shell, of what kind or calibre could not be even guessed, had fallen on
+top of an establishment where a number of women and girls were employed.
+And many of these had been killed or wounded. There were heart-rending
+scenes, which it is not good to dwell upon. But, even in the terror and
+horror, French efficiency was at the fore.
+
+Ambulances were summoned, a guard was thrown about the building, and the
+work of aiding the injured and tenderly carrying out the dead was begun.
+A vast and excited throng increased in size about the building that had
+been hit and there was much excitement for a time.
+
+Tom and Jack managed to get to a place where they could get a view of
+the havoc wrought to the structure itself, and the first thing that
+impressed them was mentioned by Jack, who said:
+
+"They didn't use a very big shell, or there wouldn't have been such
+comparatively slight material damage done."
+
+"The force was mostly expended inside the building," suggested Tom.
+
+"Even so, if it had been a big shell, the kind they fired at Verdun and
+Liege, there'd be a crater here big enough to put a church in. As it is,
+only the two top stories are wrecked."
+
+"That's right," agreed Tom. "I wonder what sort of explosive they are
+using? Must have been one from a bombing aeroplane."
+
+"No, monsieur," interrupted a _gendarme_ who was standing near. "Pardon,
+for speaking," he went on, with a salute, "but there was no airship
+observed over Paris at all. The shell came out of the clear sky."
+
+"But it couldn't have," insisted Jack, in reply to this policeman. "If
+the Germans are firing on Paris they must have some place from which to
+shoot their gun. Either on the ground or from an airship."
+
+"It was not an airship," insisted the _gendarme_. "Excuse me for
+insisting this to one who is in the air service," and he pointed with
+pride to the uniform the boys wore, "but I have seen several air raids,
+and I know! There was no airship seen, or I would have blown the alarm,"
+and he motioned to his whistle which he carried for that purpose.
+
+"It could have come from an immense airship, so high up as to be beyond
+observation," suggested Jack. "That's possible. Probably the Germans
+didn't want to be bombarded themselves by aircraft guns here, and they
+flew high."
+
+The police officer shook his head. He was not convinced.
+
+"But, man, how else could it be?" asked Tom, in some heat. "The Huns
+have to rest their gun somewhere, and you--Say, Jack!" he suddenly
+exclaimed, his face paling slightly, "you don't suppose they have broken
+through, do you?"
+
+"Through our lines about Paris? Never!" cried the police officer. "They
+shall not pass! Our brave soldiers have said it, and they will maintain
+it. They shall not pass!"
+
+"And yet," mused Tom, as he looked at the rescue work going on, "what
+other explanation is there? It's a bombardment of Paris all right, by
+German shells. If they don't come from an aeroplane, high up, they must
+come--"
+
+His words were drowned by another great concussion, but farther off. The
+ground trembled, but there was no sign of flying debris.
+
+"Another!" cried the _gendarme_. "There goes the gun again!"
+
+"I didn't hear any gun," observed Jack. "What we heard was the explosion
+of the shell. Look up, Tom, and see if there's a Hun plane in sight. If
+there is, pity we haven't our machines right now."
+
+The boys carried, slung over their shoulders, powerful binoculars, and
+with these they swept the sky. Others about them were doing the same. By
+this time the most seriously injured had been carried to the hospitals,
+and the dead had been removed, while those only slightly hurt, as well
+as those in the factory not at all injured, were telling their
+experiences. The second explosion seemed to create great terror.
+
+"There isn't a sign of a hostile plane," said Tom, as he swept the sky
+with his glasses.
+
+"I can't see any either," observed Jack. "And yet--"
+
+There sounded the unmistakable roar of an aircraft's propeller.
+
+"There she is!" cried some one.
+
+But it was one of the first of a series of French planes that had
+hastily ascended to search the heavens for a sight of the supposed
+German craft that had dropped the bombs.
+
+"What a chance we're missing!" murmured Jack.
+
+"Yes," agreed Tom. "But they're going to have some flight before they
+locate that Hun. There isn't so much as a speck in the sky except the
+French craft."
+
+"Let's go and see where that other explosion was," suggested Jack, when
+they had observed several of the French planes scurrying to and fro over
+the city, climbing higher and higher in search of the enemy.
+
+"I'm with you," announced Tom. "I wonder what dad thinks of this?"
+
+"It'll be something new for him," said Jack. "He'll have a good chance
+to see how his stabilizer works, if they're using it on these planes
+here. And maybe he can invent a better one."
+
+"Perhaps," returned Tom. "But, Jack, do you know I'm worried about one
+thing."
+
+"I have more than that on my mind, Tom. There are mighty serious times
+all about us, and it's terrible to think of those poor women and girls
+being killed like rats in a trap. I'd just like to be in my plane, and
+with a full gun, and then have a go at the Hun who did this."
+
+"So would I," agreed Tom, as they made their way out of the crowd and in
+the direction in which many of the populace were hurrying to go to the
+scene of the second explosion. "But, Jack, do you know I shouldn't be
+surprised to learn that the shell was not from an airship at all."
+
+"Where would it be from then?"
+
+"The Germans may have massed such a lot of troops at some point opposite
+the French lines, that they have broken through and have brought up
+some of their heavy guns."
+
+Jack shook his head.
+
+"I don't believe they could do it," he said. "You know the nearest
+German line is about seventy miles from Paris. If they had started to
+break through, and had any success at all, the news would have reached
+here before this. And reinforcements would be on the way. No, it can't
+be. There must be some other explanation."
+
+"But what is it?" asked Tom. "They've got to get nearer than seventy
+miles to bombard Paris. You know that."
+
+"I don't think I really _know_ anything about this war," said Jack
+simply. "So many strange, things have happened, so many old theories
+have been discarded, and so many new things have been done that we don't
+know where we are."
+
+"Well that's true. And yet how could the Germans get near enough to
+bombard Paris without some word of it coming in?"
+
+"I don't know. But the fact remains. Now let's get to where the second
+shell fell. Maybe we can see a fragment of it and--"
+
+Once again the words were interrupted by an explosion. This time it was
+closer and the shock was greater.
+
+"That's the third!" cried Jack.
+
+"Yes," added Tom, looking at his watch, "and it's just half an hour
+since the first one fell. That indicates they're firing every fifteen
+minutes. Jack, there's something weird about this."
+
+"You're right. That last one came rather close, too. I wonder where it
+fell?"
+
+A man, passing them, running in a direction away from the sound of the
+last explosion, heard Jack's question. He paused long enough to say;
+"That shell fell in Rue Lafayette. Several buildings are in ruins. Many
+have been killed! It is terrible!"
+
+"Rue Lafayette!" gasped Jack. "That--"
+
+"That's where my father is supposed to be staying!" exclaimed Tom.
+"Come! We must see what happened!"
+
+
+
+
+CHAPTER VII
+
+TOM'S FATHER
+
+
+With anxious hearts the Air Service boys ran on. There was no need to
+ask their way, for they had but to follow the throng toward the scene of
+the most recent exhibition of the Hun's frightfulness and horror.
+
+As they drew near the Rue Lafayette, where Mr. Raymond had said he
+intended to stay while in Paris, the boys were halted by an officer on
+the outskirts of the throng.
+
+"Pardon, but you may not go farther," he said, courteously enough.
+"There is danger. We are about to sound the alarm so that all may take
+to shelter. The Boches are raiding Paris again."
+
+"We know it," said Tom. "But it is no idle curiosity that takes us on."
+
+"No?" politely questioned the policeman.
+
+"No. I am seeking my father. He wrote to me that he would stop in the
+Rue Lafayette, and I have not heard from him since. I was told that the
+last shell fell in that street."
+
+"It did," assented the officer, "and it demolished two houses and part
+of another. Many were killed and injured."
+
+"Then I must see if my father is among them!" insisted the young
+aviator.
+
+"Pardon, monsieur, it is not possible. I have my instructions, and--"
+
+He stopped, and for the first time seemed to become aware of the
+uniforms worn by Tom and Jack. Then the officer saluted as though proud
+to do it.
+
+"Ah," he murmured. "Of the Lafayette Escadrille! You may go where you
+will. Only I hope it is not into danger," he said, as he drew aside for
+them to pass. "Pardon, I did not at first sense who you were. France
+owes you much, messieurs. Keep your lives save for her!"
+
+"We will," promised Tom, as he hurried on, followed by Jack.
+
+They came to the head of the street they sought, and, looking down it,
+beheld ruins greater than they had seen before. As the officer had said,
+two buildings had been completely demolished, and a third partly so, the
+wreckage of all mingling. And amid these ruins police and soldiers were
+working frantically to get out the injured and remove the dead, of whom
+there was a sad number.
+
+Tom's face was white, but he kept his nerve. He had been through too
+many scenes of horror, had been too near death too often of late, as had
+his chum, to falter now, even though his father might be among those
+buried in the wreckage caused by the German shell.
+
+"Do you know what number your father was to stop at?" asked Jack.
+
+"Yes, I have his letter," Tom answered. "I'm afraid, Jack, it was in one
+of those buildings that have been blown apart."
+
+"No, Tom!"
+
+"I'm afraid so. But, even at that, he may have had a chance for his
+life. He may have been out, or, after all, he may not have arrived yet.
+I'm not going to give up hope until I have to."
+
+"That's the way to talk, old man. I'm with you to the last."
+
+They pressed on, and populace and officers alike gave way before them as
+they saw the uniforms.
+
+"We've got to help!" declared Tom. "We must pitch in, Jack, and lend a
+hand here. The soldiers seem to be in charge. Let's report to the
+commanding officer and offer our services."
+
+"But your father?"
+
+"That's the best way to find him if he's in those ruins. Let us help get
+the unfortunates out. I hope I don't find him, but I must make sure."
+
+Making their way through the press of people, which, under order of the
+police and military authorities, had begun to disperse in some small
+measure, Tom and Jack reported to the officer in charge, giving him
+their names and rank, at the same time showing their papers.
+
+"We want to help," the lads told him.
+
+"And I ask no better," was the quick response. "There are dead and dying
+under that pile. They must be gotten out."
+
+And then began heart-rending scenes. Tom and Jack did valiant work in
+carrying out the dead and dying, in both of which classes were men,
+women and children.
+
+The German beasts were living up to the mark they had set for themselves
+in their war of frightfulness.
+
+Each time a dead or injured man was reached, to be carried out for
+hospital treatment or to have the last sad rites paid him, Tom nerved
+himself to look. But he did not see his father, and some small measure
+of thankfulness surged into his heart. But there were still others
+buried deep under the ruins, and it would be some time before their
+bodies, dead or alive, could be got out.
+
+As the soldiers and police worked, on all sides could be heard
+discussions as to what new form or manner of weapon the Germans were
+using thus to reach Paris. Many inclined to the theory that it was a new
+form of airship, flying so high as to be not only beyond ordinary
+observation, but to be unreachable by the type of planes available at
+Paris.
+
+"If we could only find a piece of the shell we could come nearer to
+guessing what sort of gun fired it," remarked Tom, as the two Air
+Service boys rested a moment from their hard, terrible labors.
+
+"Do you mean if it was dropped from an airship it wouldn't have any
+rifling grooves on it?" asked Jack.
+
+"That's it. A bomb, dropped from an aeroplane, would, very likely, be
+only a sort of round affair, set to explode on contact or by a time
+fuse. But if it was a shell fired from a long-range gun, there might be
+enough of it left, after the explosion, to observe the rifling."
+
+"There isn't a gun with a range long enough to reach Paris from the
+nearest German lines, unless they have broken through," said Jack.
+
+"Well, the last may have happened; though I should think we'd have got
+some word of it in that case. There'd be fierce fighting if the Germans
+tried that, and we'd rush reinforcements out in taxicabs as the Paris
+soldiers went out once before."
+
+"Do you think then," asked Jack, as they went back, after their brief
+respite, to their appalling labors, "that they have a gun long enough
+to fire from their nearest point, which is about seventy miles from this
+city?"
+
+"I don't know what to think," remarked Tom. "It seems like a wild dream
+to speak of a gun that can shoot so far; and yet reality is over-topping
+many wild dreams these days. I'm going to reserve judgment. My chief
+concern now, though of course I'm not going to let it interfere with my
+work, is to find my father. If he should have been in here, Jack--"
+
+Tom did not finish, but his chum knew what he meant, and sympathized
+with his unexpressed fear for the safety of Mr. Raymond.
+
+Digging and delving into the ruins, they brought out the racked and
+maimed bodies, and there was more than one whose eyes were wet with
+tears, while in their hearts wild and justifiable rage was felt at the
+ruthless Germans.
+
+Ten had been killed and nearly twice that number wounded in the third
+shell from the Hun cannon.
+
+From a policeman Tom learned that one of the two buildings that had been
+demolished was the number given by Mr. Raymond as the place he would
+stay.
+
+"The place he picked out may have been full, and he might have gone
+somewhere else," said Tom. "We've got to find out about that, Jack."
+
+"That's right. I should think the best person, or persons, to talk to
+would be the janitors, or '_concierges_,' as they call 'em here."
+
+"I'll do that," responded Tom.
+
+Aided by an army officer, to whom the boys had recommended themselves,
+not only by reason of their rank, but because of their good work in the
+emergency, they found a man who was in charge of all three buildings as
+a renting agent. Fortunately he had his books, which he had saved from
+the wreck.
+
+"You ask for a Monsieur Raymond," he said, as he scanned the begrimed
+pages. "Yes, he was here. It was in the middle building he had a room."
+
+"In the one that was destroyed?" asked Tom, his heart sinking.
+
+"I regret to say it--yes."
+
+"Then I--then it may be all up with poor old dad!" and Tom, with a
+masterful effort, restrained his grief, while Jack gripped his chum's
+hand hard.
+
+
+
+
+CHAPTER VIII
+
+WHERE IS MR. RAYMOND?
+
+
+Tom Raymond, having gone through a hard school since he began flying for
+France, soon recovered almost complete mastery of himself. The first
+shock was severe, but when it was over he was able to think clearly.
+Indeed the faculty of thinking clearly in times of great danger is what
+makes great aviators. For in no other situation is a clear and quick
+brain so urgently needed.
+
+"Well, I'm sure of one thing, Jack," said Tom, as they walked away from
+the fateful ruins. "Of those we helped carry out none was my father. He
+wasn't among the injured or dead."
+
+"I'm sure of that, too. Still we mustn't count too much on it, Tom. I
+don't want you to have false hopes. We must make sure."
+
+"Yes, I'm going to. We'll visit the hospitals and morgues, and talk with
+the military and police authorities. In these war times there is a
+record of everybody and everything kept, so it ought to be easy to trace
+him."
+
+"He arrived all right, that's settled," declared Jack. "The agent's
+record proves that."
+
+"Yes. I'd like to have a further talk with that agent before we set out
+to make other inquiries."
+
+This Tom was able to bring about some time later that day. The agent
+informed the lad that Mr. Raymond, contrary to his expectations, had
+arrived only the day before. Where he had been delayed since arriving in
+Europe was not made clear.
+
+"But was my father in the building at the time the shell struck here?"
+asked Tom. "That's what I want to know."
+
+Of this the man could not be certain. He had seen Mr. Raymond, he said,
+an hour or so before the bombardment, and the inventor was, at that
+time, in his room. Then he had gone out, but whether he had come back
+and was in the house when the shell struck the place, could not be said
+with certainty.
+
+But if he had been in his apartment there was little chance that he had
+been left alive, for the explosion occurred very near his room,
+destroying everything. Tom hoped, later, to find some of his father's
+effects.
+
+"There is just a chance, Jack," said the inventor's son, "that he wasn't
+in his room."
+
+"A good chance, I should say," agreed the other. "Even if he had
+returned to his room, and that's unlikely, he may have run out at the
+sound of the first explosion, to see what it was all about."
+
+"I'm counting on that. If he was out he is probably alive now. But if he
+was in his room--"
+
+"There would be some trace of him," finished Jack.
+
+"And that's what we've got to find."
+
+The police and soldiers were only too willing to assist Tom in his
+search for his father. The ruins, they said, would be carefully gone
+over in an endeavor to get a piece of the German shell to ascertain its
+nature and the kind of gun that fired it. During that search some trace
+might be found of Mr. Raymond.
+
+It did not take long to establish one fact--that the inventor's body was
+not among the dead carried out. Nor was he numbered with the injured in
+the hospitals. Careful records had been kept, and no one at all
+answering to his description had been taken out or cared for.
+
+And yet, of course, there was the nerve-racking possibility that he
+might have been so terribly mutilated that his body was beyond all human
+semblance. The place where his room had been was a mass of splintered
+wood and crumbled masonry. There was none of his effects discernible,
+and Tom did not know what to think.
+
+"We've just got to wait," he said to Jack, late that afternoon, when
+their search of the hospitals and morgues had ended fruitlessly.
+
+Meanwhile the French airmen had been scouring the sky for a sight of the
+German craft that might have released the death-dealing bombs on the
+city. But their success had been nil. Not a Hun had been sighted, and
+one aviator went up nearly four miles in an endeavor to locate a hostile
+craft.
+
+Of course it was possible that a super-machine of the Huns had flown
+higher, but this did not seem feasible.
+
+"There is some other explanation of the bombardment of Paris, I'm sure,"
+said Tom, as he and Jack went to their lodgings. "It will be a surprise,
+too, I'm thinking, and we'll have to make over some of our old ideas and
+accept new ones."
+
+"I believe you're right, Tom. But say, do you remember that fellow we
+saw in the train--the one I thought was a German spy?"
+
+"To be sure I remember him and his _metzel suppe_. What about him? Do
+you see him again?" and Tom looked out into the street from the window
+of their lodging.
+
+"No. I don't see him. But he may have had something to do with shelling
+the city."
+
+"You don't mean he carried a long-range gun in his pocket, do you,
+Jack?" and Tom smiled for the first time since the awful tragedy.
+
+"No, of course not. Still he may have known it was going to happen, and
+have come to observe the effect and report to his beastly masters."
+
+"He'd be foolish to come to Paris and run the chance of being hit by his
+own shells."
+
+"Unless he knew just where they were going to fall," said Jack.
+
+"You have a reason for everything, I see," remarked Tom. "Well, the next
+time we go to headquarters we'll find out what they learned of this
+fellow. You know we started the secret service agents on his trail."
+
+"Yes, I know. Well, I was just sort of wondering if he had anything to
+do with the bombardment of Paris. You've got to look for German spies
+now, even under your bed at night."
+
+The boys felt they could do nothing more that day toward finding Mr.
+Raymond. A more detailed and careful search of the ruins might reveal
+something. Until this was accomplished nothing could be done.
+
+They ate a late supper, without much in the way of appetites, it must be
+confessed, and then went out in the streets of Paris. There seemed to be
+few signs of war, aside from the many soldiers, and even the
+bombardment of a few hours earlier appeared to have been forgotten. But
+of course there was grief in many hearts.
+
+It was early the next morning, when Tom and Jack were getting ready to
+go back to the ruins in the Rue Lafayette, that, as they left their
+lodgings, they heard in the air above them the familiar sounds of
+aeroplanes in flight, and the faint popping of machine guns, to which
+was added the burst of shrapnel.
+
+"Look!" cried Jack. "It's a battle in the air. The Huns are making
+another raid. Now we'll see how they bomb the city."
+
+But it did not turn out to be that sort of raid. The German craft were
+flying low, apparently to get a view of the havoc wrought the day
+before. Possibly photographs were being taken.
+
+But the French aeroplanes were ready for the foe, and at once arose to
+give battle, while the anti-aircraft guns roared out a stern order to
+retreat. It was a battle above the city and, more than once, Tom and
+Jack wished they could be in it.
+
+"We'll have to get back to our hangars soon," mused Tom, as they watched
+the fight. "We can't be slackers, even if I can't find my father," he
+added bravely.
+
+The French planes were too much for the Germans, and soon drove them
+back beyond the Hun lines, though perhaps not before the enemy aviators
+had made the observations desired.
+
+"Well, they didn't see much," remarked Jack. "As far as any real damage
+was done to Paris it doesn't count, from a military standpoint."
+
+"No, you're right," agreed Tom. "Of course they have killed some
+noncombatants, but that seems to be the Boche's principal form of
+amusement. As for getting any nearer to the capture of Paris this way,
+he might as well throw beans at the pyramids. It's probably done for the
+moral, or immoral, effect."
+
+And this seemed to be the view taken of it by the Paris and London
+papers. The method of bombardment, however, remained a mystery, and a
+baffling one. This was a point the military authorities wished to clear
+up. To that end it was much to be desired that fragments of the shell
+should be found. And to find them, if possible, a careful search was
+made, not only in the ruins of the Rue Lafayette, but at the other two
+places where the explosions had occurred.
+
+In no place, however, was a large enough fragment found to justify any
+conclusive theories, and the Parisians were forced to wait for another
+bombardment--rather a grim and tense waiting it was, too.
+
+But the careful search of the Rue Lafayette ruins proved one thing. The
+body of Tom's father was not among them, though this did not make it
+certain that he was alive. He may have been totally destroyed, and this
+thought kept Tom from being able to free his mind of anxiety. He dared
+not cable any news home, and all he could do was to keep on hoping.
+These were anxious days for him and Jack.
+
+Their leave of absence had been for a week only, but under the
+circumstances, and as it was exceptionally quiet on their sector, they
+were allowed to remain longer. Tom wanted to make a more thorough search
+for his father, and the police and military authorities helped him. But
+Mr. Raymond seemed to have completely disappeared. There was no trace of
+him since the agent for the Rue Lafayette buildings had seen him leave
+his room just prior to the falling of the shell.
+
+Jack inquired about the man he suspected of being a German spy. The
+secret service men had him under observation, they reported, but, as
+yet, he had not given them any cause to arrest him. They were waiting
+and watching.
+
+Meanwhile active preparations were under way, not only to discover the
+source of the bombardment of Paris, but to counteract it. Extra
+anti-aircraft guns, of powerful calibre, were erected in many places
+about the city, and more airmen were summoned to the defense.
+
+As yet there had been no resumption of the bombardment, and there were
+hopes that the German machine, whatever it was, had burst or been put
+out of commission. But on the second day of the second week of the boys'
+stay in Paris, once more there was the alarm and the warning-from the
+soldiers and police, and again came that explosion.
+
+The bombardment of Paris was being renewed!
+
+
+
+
+CHAPTER IX
+
+VARIOUS THEORIES
+
+
+Two things were at once apparent to Tom and Jack as they hurried out of
+their _pension_. One was that the people of Paris were not seeking
+shelter after the warnings as quickly as they had done at first, and the
+other was that there was evident curiosity on all sides to see just what
+damage would be done, and from which direction it would come. With an
+almost reckless disregard for their safety, if not for their lives, the
+Parisians fairly flocked out of doors to see the results of the Huns'
+bombardment. It was in vain that the police and military urged them to
+seek safety in cellars or the places provided.
+
+This time only one shell fell near enough to Tom and Jack to make the
+explosion heard, and that was so faint as to indicate that it was some
+distance off. What damage had been done could only be guessed at.
+
+"But we'll find out where it is, and go take a look," said Jack.
+
+"Maybe it'll hit right around here if we stay," suggested his chum.
+
+"Well, I'm not taking that chance," Jack went on. "Let's find out where
+it landed this time."
+
+This they could do through their acquaintance with the military
+authority of the district where they were then staying. A telephonic
+report was at once received, giving the quarter where the shell had
+landed. It had fallen in one of the public squares, and though a big
+hole had been torn in the ground and pavement, and several persons
+killed and wounded, no material damage had been done. As for any
+military effect of the shell, it was nil.
+
+The firing was done in the early evening hours, and Tom and Jack learned
+that, almost to the second, the shots were fifteen minutes apart.
+
+There was one theory that an underground passage had been made in some
+manner to within a comparatively few miles of Paris, and from that point
+an immense mortar sent up the shells in a long trajectory.
+
+Another theory was that traitors had let the Germans through the French
+lines at a certain place, so they could get near enough to Paris to
+bombard it.
+
+And of course the gigantic airship theory had its adherents.
+
+But, for a time at least, no one would admit the possibility of a gun
+with range sufficient to shoot into Paris from the nearest German lines.
+The range, sixty-odd miles, seemed too great for practical belief,
+however nicely it might work out in theory.
+
+"And you must remember that the gun, if gun it is, couldn't be in the
+very first German line," said Tom, who had studied ordnance. "It must be
+at least ten miles back, to allow for sufficient protection from the
+French guns. That would make it shoot about seventy-two miles, and I
+don't believe any gun on earth could do it!"
+
+"Neither do I," added Jack. "We've got to dope out something else. But
+this isn't finding your father, Tom."
+
+"I know it, and I don't mind admitting I'm clean discouraged about him,
+Jack. If he's alive why doesn't he send me some word? He must know where
+I am, and, even if he doesn't know I'm in Paris, they would forward any
+message he might send to our aeroplane headquarters."
+
+"That's right. But what are you going to do about it?"
+
+"I hardly know. He may still be in Paris, but it's such a big city that
+it's hard to find him. Then, too, I'm thinking of something else."
+
+"What's that, Tom?"
+
+"Well, dad may not want us to know where he is."
+
+"Why in the world would he want such a thing as that?"
+
+"Well, he might be followed, or bothered by spies. Perhaps he has come
+over to do some special work for the French or English army people.
+Maybe a spy was after him just before the big German gun wrecked his Rue
+Lafayette house. He may have considered this a good chance to play dead,
+and that's why he doesn't send some word to me."
+
+"That's a good theory. But it isn't very comforting."
+
+"No, but there isn't much comfort in war times. We've got to make the
+best of it."
+
+"I guess you're right, Tom. Now do you want to go look at the latest
+work of the Hun?"
+
+"Might as well. The bombardment seems over for the night."
+
+"I wonder why it is they don't fire after dark."
+
+"Probably afraid of giving the location of their cannon away by the
+flashes. They'd be seen at night; but during the day, if they used
+smokeless powder, or a smoke screen in case they can't get smokeless
+powder for such a big gun, it would be hard to locate the place where
+the shots come from. So we're comparatively safe after dark, it seems."
+
+Later this was not to prove to be the case, but it was when Tom spoke.
+
+The boys went to the section of the city in which the last shells had
+fallen. While comparatively little damage had been done, a number of
+persons had been killed and injured, children among them. Some fragments
+of the shells were picked up, but not enough to make certain any
+particular theory in regard to the gun.
+
+"But if it's a gun, where could it be placed?" queried Tom of an
+officer. "The Germans haven't broken through, have they?"
+
+The French officer shook his head.
+
+"No. And please God they will never get through," he said. "But there is
+a gun somewhere, I am sure of that."
+
+"Do you mean to say within ten or fifteen miles of Paris?" Jack wanted
+to know.
+
+"I can not be sure. It is true there may have been traitors. We have
+them to contend with as well as spies. But our line is intact, and at no
+point along it, near enough to it to fire into Paris from an ordinary
+gun, can the Germans be found."
+
+"Then it must be an extraordinary gun," suggested Jack.
+
+"It may well be--perhaps it is. Yet, as I said, there may have been
+traitors. There may be a gun concealed somewhere closer to Paris than we
+dream. But we shall find it, messieurs! Who knows? Perhaps you may be
+the very ones yourselves to locate it, for we are depending on you
+soldiers of the air."
+
+And it was not long before this talk came back to Tom and Jack with
+impressive recollection.
+
+And meanwhile the bombardment of Paris went on, usually during the late
+afternoon or early morning hours--never at night, as yet.
+
+Yet with all the frightfulness of which the unscrupulous Huns were
+capable, it was impossible to dampen for long the spirits of the French.
+Soon they grew almost to disregard the falling shells from the hidden
+German gun. Of course there were buildings destroyed, and lives were
+lost, while many were frightfully maimed. But if Germany depended on
+this, as she seemed to, to strike terror to the hearts of the brave
+Frenchmen the while a great offensive was going on along the western
+front, it failed. For the people of Paris did not allow themselves to be
+disheartened, any more than the people of London did when the Zeppelins
+raided them.
+
+Indeed one Paris paper even managed to extract some humor out of the
+grim situation. For one day, following the bombardment, a journal
+appeared with "scare" headlines, telling about eleven "lives" being
+lost. But when one read the account it was discovered that the lives
+were those of chickens.
+
+And this actually happened. A shell fell on the outlying section and
+blew up a henhouse, killing nearly a dozen fowls and blowing a big hole
+in the ground.
+
+There were other occasions, too, when the seemingly superhuman
+bombardment was not worth the proverbial candle. For the shells fell in
+sections where no damage was done, and where no lives paid the toll.
+Once a shell went through a house, passing close to an aged woman, but
+not hurting her, to explode harmlessly in a field near by.
+
+And it was with such accounts as these that the Paris papers kept up the
+spirits of the inhabitants. Meanwhile the Germans kept firing away at
+quarter-hour intervals, when the gun was in action.
+
+"I wonder if there is any chance of us getting in at the game?"
+questioned Jack of Tom one night.
+
+"I shouldn't be surprised. As that officer said, they'll have to depend
+on the aircraft to locate the gun, I'm thinking."
+
+"And you think we have a chance?"
+
+"I don't see why not," replied Tom. "We've been off duty long enough.
+I'd like to get back behind the propeller again, and with a drum or two
+of bullets to use in case we sight a Hun plane. Let's go and send word
+to our captain that we've had enough of leave, and want to go out
+again."
+
+"All right. But what about your father?"
+
+"Well, I don't know what to say," answered Tom. "I'm about convinced
+that he wasn't killed, or even hurt, in any of the bombardments of
+Paris. But where he is I don't know. I guess, as a matter of duty to
+France, I'll have to let my private affairs go and--"
+
+At that instant there sounded an explosion the character of which the
+two boys well knew by this time.
+
+"The big gun again!" cried Jack.
+
+"Yes, and they're firing after dark!" added Tom. "This may be just the
+chance the airmen have been waiting for--to locate the piece by the
+flashes. Come on out and see what's doing!"
+
+Together they rushed from their room.
+
+
+
+
+CHAPTER X
+
+THE "DUD"
+
+
+Much the same sort of scene was going on in the streets of Paris as Tom
+and Jack had witnessed when first the populace realized that they were
+under fire from a mysterious German cannon. There was the initial
+alarm--the warnings sounded by the police and soldiers, warnings which
+were different from those indicating a Zeppelin or aircraft raid, and
+then the hurry for cover.
+
+But it was noticeable that not so many of the people rushed for a secure
+hiding place as had done so at first.
+
+"They're not so afraid of the big gun as they were," observed Jack, as
+he hurried along with his chum.
+
+"No. Though it's just as well to be a bit cautious, I think. The people
+of Paris are beginning to lose fear because they see that the German
+shells don't do as much damage as might be expected."
+
+"You're right there, Tom," said Jack. "The shells are rather small, to
+judge by the damage they do. I wonder why that is?"
+
+"Probably their gun, or guns, can't fire any larger ones such a long
+distance, or else their airships can't carry 'em up above the clouds to
+drop on the city."
+
+"Then you still hold to the airship theory?"
+
+"Well, Jack, I haven't altogether given it up. I'm open to conviction,
+as it were. Of course I know, in theory, a gun can be made that will
+shoot a hundred miles, if necessary, but the cost of it, the cost of the
+charge and the work of loading it, as well as the enormous task of
+making a carriage or an emplacement to withstand the terrific recoil,
+makes such a gun a military white elephant. In other words it isn't
+worth the trouble it would take--the amount of damage inflicted on the
+enemy wouldn't make it worth while."
+
+"I guess you're right, Tom. And yet such a gun would make a big scare."
+
+"Yes, and that's what the Germans are depending on, more than anything
+else."
+
+"But still don't you think the French will have to do something toward
+silencing the gun?"
+
+"Indeed I do! And I haven't a doubt but the French command is working
+night and day to devise some plan whereby the gun can be silenced."
+
+"There go the aviators now, out to try to find the big cannon,"
+observed Jack, as he gazed aloft.
+
+Soaring over Paris, having hastened to take the air when the signal was
+given, were a number of planes, their red, white and blue lights showing
+dimly against the black sky. They were off to try to place the big gun,
+if such it was, or discover whether or not some Hun plane was hovering
+over the city, dropping the bombs.
+
+As Jack and Tom hastened on, in the wake of the crowd, which was
+hurrying toward the place where the latest shells had fallen, again came
+a distant explosion, showing that the gun had been fired again.
+
+"Fifteen-minute interval," announced Tom, looking at his watch. "They're
+keeping strictly to schedule."
+
+"Night firing is new for the big gun," said Jack. "I do hope they'll be
+able to locate the cannon by the flashes."
+
+"It isn't going to be easy," asserted Tom.
+
+"Why not?"
+
+"Because you can make up your mind if the Germans were afraid to fire
+the piece at night at first for fear of being discovered, and if now
+they are firing after dark, they have some means of camouflaging the
+flash. In other words they have it hidden in some way."
+
+"Well, I suppose you're right. But say, Tom, old man! what wouldn't I
+give to be able to be up in the air with those boys now?" and Jack
+motioned to the scouts who were flitting around in the dark clouds,
+seeking for that which menaced the chief city of the French nation.
+
+"I'd like to be there myself," said Tom. "And if this keeps up much
+longer I'm going to ask permission for us to go up and see what we can
+do."
+
+"Think they'll let us?"
+
+"Well, they can't any more than turn us down. And we've got to get at it
+in a hurry, too, or we'll have to report back at our regular station. We
+aren't doing anything here, except sit around."
+
+"No, we must get busy, that's a fact," said Jack. "It's about time we
+downed some Hun scout, or broke up one of their 'circus' attacks. I've
+almost forgotten how a joy stick feels."
+
+A "joy stick" is a contrivance on an aeroplane by the manipulation of
+which the plane is held on a level keel. If the joy stick control is
+released, either by accident (say when the pilot is wounded in a fight),
+or purposely, the plane at once begins to climb, caking its passenger
+out of danger.
+
+Once the joy stick is released it gradually comes back toward the
+pilot. The machine climbs until the angle formed is too great for it to
+continue, or for the motor to pull it. Then it may stop for an instant
+when the motor, being heavier, pulls the plane over and there begins the
+terrible "nose spinning dive," from which there is no escape unless the
+pilot gets control of his machine again, or manages to reach the joy
+stick.
+
+"Well, we'll have to get in the game again soon," said Tom. "But what do
+you say to taking a taxi? This explosion is farther than I thought."
+
+Jack agreed, and they were soon at the place where the last German shell
+had fallen--that is as near as the police would permit.
+
+A house had been struck, and several persons, two of them children,
+killed. But, as before, the military damage done was nothing. The
+Germans might be spreading their gospel of fear, but they were not
+advancing their army that way.
+
+As Tom and Jack stood near the place where a hole had been blown through
+the house, another explosion, farther off, was heard, and there was a
+momentary flare in the sky that told of the arrival of another shell.
+
+For a few seconds there was something like a panic, and then a voice
+struck up the "Marseillaise," and the crowd joined in. It was their
+defiance to the savage Hun.
+
+A few shots were fired by the Germans, but none of them did much damage,
+and then, as though operating on a schedule which must not, under any
+circumstances, be changed, the firing ceased, and the crowds once more
+filled the streets, for it was yet early in the night.
+
+The next morning the boys went to report, as they did each day,
+expecting that they might be called back to duty. They also found, after
+being told that their leave was still in effect, that some of the
+aviators who had gone up the night before, to try to locate the German
+gun, were on hand.
+
+"Now we can ask them what they saw," suggested Jack.
+
+"That's what we will," assented Tom.
+
+But the airmen had nothing to report. They had ascended high in search
+of a hostile craft carrying a big gun, but had seen none.
+
+They had journeyed far over the German lines, hoping to discover the
+emplacement of the gun, if a long range cannon was being used. But they
+saw nothing.
+
+"Not even flashes of fire?" asked Tom.
+
+"Oh, yes, we saw those," an aviator said. "But there were so many of
+them, and in so many and such widely scattered places, that we could
+not tell which one to bomb. We did manage to hit some, though with what
+effect we could not tell."
+
+"Then the German gun is still a mystery," observed Tom.
+
+"It is. But we shall discover it soon. We will never rest until we do!"
+
+So more and new and different theories continued to be put forth
+regarding the big cannon, if such it was. Ordnance experts wrote
+articles, alike in London, Paris, and New York, explaining that it was
+possible for a cannon to be within the German lines and still send a
+shell into the French capital. But few believed that it was feasible.
+The general opinion was that the gun was of comparative short range, and
+was hidden much nearer Paris than the sixty or seventy-odd miles away,
+beyond which stretched the German line of trenches.
+
+Meanwhile Tom, though making careful inquiries, had learned nothing of
+his father. He did not feel it would be wise to cable back home, and ask
+what the news was there.
+
+"It might spoil dad's plans if I did that," said Tom to his chum, "and
+it would worry the folks in Bridgeton to know that I haven't yet seen
+him in France. No, I'll just have to wait."
+
+And wait Tom did, though there is no harder task in all the world.
+
+It was one morning, after a night bombardment on the part of the
+Germans, that Jack, who had been out for a morning paper, came rushing
+into the room where Tom was just awakening.
+
+"Great news, old man! Great!" cried Jack, waving the paper about his
+head.
+
+"You mean about a victory?" asked Tom.
+
+"No, not exactly, though it may lead to that. And it isn't any news
+about your father, I'm sorry to say. It's about the German gun. A 'dud'
+fell last night."
+
+"A 'dud'?" repeated Tom, hardly sensing what Jack said.
+
+"Yes, you know! A shell that didn't explode. Now they have a whole one
+to examine, and they can find out what sort of gun shot it. This paper
+tells all about it. Come on! Let's go for a look at the 'dud'!"
+
+
+
+
+CHAPTER XI
+
+A MONSTER CANNON
+
+
+Tom, dressing hastily, read the account in the Paris paper of the fall,
+in an outlying section of the city, of one of the German shells that
+failed to explode. It was being examined by the military authorities, it
+was stated, with a view to finding out what sort of gun fired it, so
+that measures might be taken to blow up the piece or render it useless
+to the enemy.
+
+"That sounds good to me," said Tom, as they made a hasty breakfast.
+"This is getting down to a scientific basis. An unexploded shell ought
+to give 'em a line on the kind of gun that fired it."
+
+"The only trouble," said Jack, "is that the shell may go off when they
+are examining it."
+
+"Oh, trust the French ordnance experts not to let a thing like that
+happen," said Tom. "Now let's go to it."
+
+It was fortunate that Tom and Jack wore the uniforms that had so
+endeared them to France, or they might have had difficulty in gaining
+admittance to the bureau where the unexploded shell was under process
+of investigation. But when they first applied, their request was
+referred to a grizzled veteran who smiled kindly at them, patted them on
+the shoulders, called them the saviors of France, and ushered them into
+the ordnance department, where special deputies were in conference.
+
+"Yes, we have one of the Boche shells," said an officer, who spoke
+English fluently, for which Tom and Jack were glad. They could speak and
+understand French, but in a case like this, where they wanted a detailed
+and scientific explanation, their own tongue would better serve them.
+
+"And can you tell from what sort of gun it comes?" asked Tom.
+
+"It was fired from a monster cannon," was the answer. "That is a cannon
+not so much a monster in bore, as in length and in its power to impel a
+missile nearly eighty miles."
+
+"Can it be done?" asked Jack.
+
+"It has been done!" exclaimed Major de Trouville, the officer who was
+detailed to talk to the boys "It has been done. That is the gun that has
+been bombarding Paris."
+
+"But, from a military standpoint," began Tom, "is it--"
+
+"It is utterly useless," was the quick answer. "Come, I will show you
+the shell."
+
+He led them to an apartment set aside for the testing of explosives and
+working out ordnance problems, and there on a table, around which sat
+many prominent French officials, was the German shell--the "dud," as
+Jack had called it.
+
+"The charge has been drawn," explained Major de Trouville, "so there is
+no danger. And we have determined that the manner in which shots reach
+Paris from a distance of from seventy to eighty miles is by the use of a
+sub-calibre missile."
+
+"A sub-calibre?" murmured Tom.
+
+"Yes. You know, in general, that the more powder you use, and the larger
+the surface of the missile which receives it, the greater distance it
+can be thrown, providing your angle of elevation is proper."
+
+The boys understood this much, in theory at least.
+
+"Well," went on the major, "while that is true, there is a limit to it.
+That is to say you could go on using powder up to hundreds of pounds in
+your cannon, but when you get to a certain point you have to so increase
+the length of the gun, and the size of the breech to make it withstand
+the terrific pressure of gases, that it is impracticable to go any
+further. So, also, in the case of the shell. If you make it too large,
+so as to get a big surface area for the gases of the burning powder to
+act upon, you get your shell too heavy to handle.
+
+"Now of course the lighter a missile is, the farther it will go, in
+comparison to a heavy one with the same force behind it. But you can not
+get lightness and sufficient resistance to pressure without size, and
+here is where the sub-calibre comes in."
+
+"In other words the Germans have been firing a shell within a shell,"
+broke in another officer.
+
+"Exactly," said Major de Trouville. "The Germans have evolved a big gun,
+that is big as regards length, to enable the missile they fire from it
+to gain enough impulse from the powder. But the missile would be too
+large to travel all the way to Paris. So they use two. The inner one is
+the one that really gets here and explodes."
+
+"What becomes of the outer?" asked Jack.
+
+"It is a sort of container, or collar, and falls off soon after the
+shell leaves the big gun. If you will imagine a sort of bomb shell being
+enclosed in an iron case, the whole being put in a gun and fired, you
+will better get the idea. The outer case is made in two or more pieces,
+and soon after it is shot out it falls away, leaving the smaller missile
+to travel on. But here is where the cunning of the invention comes in.
+The smaller missile has all the impetus given the larger one, but
+without its weight. In consequence it can travel through eighty miles of
+atmosphere, finally reaching Paris, where it explodes."
+
+"Wonderful!" exclaimed Jack.
+
+"And yet it is merely the adaptation of an old theory," went on the
+major. "We have known of the sub-calibre theory for years, but it is not
+practicable. So we did not try it. The cost is too great for the amount
+of military damage done. And this shell, as you will see, is composed of
+two parts, each with a separate explosive chamber, each containing, as
+we discovered, a different sort of explosive. In this way if one did not
+go off, the other would, and so set off the one that failed. It is very
+clever, but we shall be more clever."
+
+"That's right!" chimed in a chorus of fellow officers.
+
+"We'll find the gun and destroy it--or all of them if they have more
+than one, as they probably have," went on the major.
+
+He showed the boys where the shell had chambers for the time fuses to
+work, much as in a shrapnel shell, which can be set to go off so many
+minutes or so many seconds after it reaches its objective point.
+
+"And so the great question is settled by the failure of this shell to
+explode," went on the major. "As soon as we saw it, and noted the
+absence of the rifling groove marks, we knew it must have been a
+sub-calibre matter. The rest was easy to figure out.
+
+"Some of us thought there might be a big airship, stationed high above
+the clouds, dropping bombs. Others inclined to the theory of a double
+shell; that is, after one had been fired from the cannon it would
+travel, say, half way and then explode a charge which would impel
+another shell toward Paris. A sort of cannon within a cannon, so to
+speak. But this is not so. Nor did the theory of a shell with a sort of
+propeller device, like that of a torpedo, prove to be right. It is much
+simpler--just sub-calibre work."
+
+"And what is going to be done about it?" asked Tom. "I mean how can the
+monster cannon be silenced?"
+
+"Ah, that is a matter we are taking up now," was the answer of Major de
+Trouville. "I fancy we shall have to call on you boys for a solution of
+that problem."
+
+"On us?" exclaimed Jack.
+
+"Well, I mean on the aircraft service. It will be their task to search
+out this great German cannon for us, to enable our gunners to destroy
+it. Or it may be that it will have to be bombed from an aeroplane."
+
+"That's the task I'd like all right!" cried Tom, with shining eyes.
+
+"Same here!" echoed Jack. "Do you suppose we'll get a chance?" he asked
+eagerly.
+
+"You may," was the reply. "It may take all the resources of our airmen
+to destroy this terror of the Germans. But it will be done, never fear!"
+
+"_Vive la France!_" cried his companions, and there was a cheer in which
+Tom and Jack joined.
+
+And so a part of the secret was discovered. It was a monster cannon that
+was devastating Paris. A great gun, the construction of which could only
+be guessed at. But it must be destroyed! That was certain!
+
+
+
+
+CHAPTER XII
+
+FOR PERILOUS SERVICE
+
+
+Tom and Jack spent some little time looking at the strange German shell.
+It was of peculiar construction, arranged so that the two explosive
+charges would detonate together or separately, according as the
+mechanism was set.
+
+But in this case it had failed to work, and the shell, falling in a bed
+of soft sand, near some new buildings which were going up, had not been
+fired by concussion, as might have happened.
+
+"And it was just French luck that it didn't go off," observed Jack.
+
+"That's right," agreed Tom. "If they hadn't had this whole shell to
+examine they wouldn't know about the big gun."
+
+So all the theories, fantastic enough some of them, about great airships
+hovering over the beautiful city, and dropping bombs from a great
+height, were practically disproved.
+
+"Well, now that you have decided it is a big German gun, the next
+question is, where is it and what are you going to do about it?"
+observed Tom, for he and Jack had been made so much of by the French
+officers that they felt quite at home, so to speak.
+
+"Ah, messieurs, that _is_ the question," declared Major de Trouville.
+"First to find the gun, and then to destroy it. The first we can do with
+some degree of accuracy."
+
+"How?" asked Tom.
+
+The major went to a large map hanging on the wall of the room. It showed
+the country around Paris and the various lines as they had been moved to
+and fro along the Western front, according as the Germans advanced or
+retreated.
+
+"You will observe," said the major, "that by describing an arc, with
+Paris as the center of the circle, and a radius of about seventy-five
+miles, you will include a small sector of the German trenches. Roughly
+speaking this arc will extend from about Hamegicourt to Conde, both
+within the German lines, I am sorry to say. Now then, somewhere in this
+arc, or perhaps back of it, the German gun is placed. Anywhere else
+where it would be possible for such a monster engine of war to be
+erected, would bring it too close to our batteries.
+
+"So that gives us the comparative location of the gun," went on the
+French officer. "But the next question is not so easy to settle--how to
+get rid of it. As I said, I think we shall have to depend on you
+airmen."
+
+"Well, we're for the job!" exclaimed Tom.
+
+"I know you are. And it may fall to you, or to your friends. I will talk
+of that later."
+
+"Have you been able to get any idea of the kind of gun it is, or why it
+fires at fifteen minute intervals?" asked Jack.
+
+"We have been able to get no really reliable information save that which
+we deduce by our observations of this shell and from what we know of the
+location of our own and the German lines," the Major went on. "Up to now
+our airmen have not been able to penetrate far enough without being
+attacked, and such few as did get well over toward the Rhine could make
+out nothing. I have no doubt the gun is well camouflaged."
+
+"And is it true that it doesn't fire at night because the Germans are
+afraid the flashes will be seen?" asked Tom.
+
+"That may have been the reason at first, but they have fired at night,
+of late, so they must have some way of concealing the flashes, or
+perhaps setting off other flashes at the same time so as to confuse our
+scouts."
+
+"It's going to be some job," murmured Jack.
+
+"You said something," agreed his chum.
+
+They remained talking a little longer, and some of the officers who
+knew the reason for Tom's visit to Paris, expressed regret that he had
+no information as yet about his father.
+
+"But take heart," one told him. "He is not dead, or we should have heard
+of it. Of course he may have fallen into the hands of the Germans, and
+then we would not know for some time."
+
+"He may have been caught," agreed Tom. "While Tuessig is out of the game
+on account of his injuries, he may be able to direct Potzfeldt, and that
+scoundrel would have good reason for trying to get revenge on us."
+
+"Ah, yes, I heard about your rescue of the young lady and her mother,"
+said the major. "It was a brave deed."
+
+"Oh, any one could have done it," said Tom, modestly.
+
+"And have you seen them since they came to Paris?" the major proceeded.
+
+"No, but I wish we could find them!" burst out Jack, and then he blushed
+at his impetuosity, while Tom murmured something about "Bessie," and
+Jack promptly told him to hold his tongue.
+
+"Perhaps you may meet them sooner than you expect," went on the French
+officer.
+
+"Now I wonder what he could have meant by that?" asked Jack, as he and
+his chum went out, after a final look at the German shell. "Does he
+know where they are?"
+
+"It wouldn't be surprising, seeing that Mrs. Gleason is probably in Red
+Cross work, and Bessie may be helping her. We should have looked them up
+before," went on Tom. "But what with searching for my father, and the
+excitement about the bombardment, I really forgot all about them."
+
+Jack did not say whether he had or not, the chances being that he had,
+more than once, thought of Bessie Gleason.
+
+During the next two days the monster cannon continued to shoot shells at
+intervals into Paris. Some did considerable damage, as any shell would
+do in a great city, and many unfortunates were killed. But there was no
+reign of terror such as, undoubtedly, the Boches hoped to create. Paris
+remained calm, and there were even jokes made about the cannon. It was
+called a "Bertha" and other names, the former referring to Bertha Krupp,
+one of the owners of the great German ordnance works.
+
+Word was given out that the French gunners on the front were trying to
+reach the big gun with their missiles. But as they were firing blindly
+it could not be said what havoc had been wrought.
+
+"But, sooner or later, we'll get the range, and get within striking
+distance," said one of the French officers. "Then we'll show them a
+trick or two."
+
+"Have the aviators done anything toward trying to find the gun?" asked
+Tom. "I mean anything more."
+
+"We are perfecting our plans for the flying corps," was the answer.
+"Perhaps you shall know more in a few days."
+
+"Well, I hope we'll be here when the fun begins," said Tom, grimly.
+"We've got another extension of leave, and I'm going to ask the police
+now, to co-operate with the military in seeking my father."
+
+"I think that will be a wise plan. We will give you all the help we
+can."
+
+But the quest for Mr. Raymond seemed a hopeless one, and as no
+confirmation could be had of his death or injury, the idea gradually
+became fixed in the minds of Tom and Jack that he had been made a German
+prisoner.
+
+"If that is so, and I can get any trace of him, I'll go over the Rhine
+to get him back," snapped Tom.
+
+"And I'll go with you!" declared his chum.
+
+It was a few days after they had inspected the German "dud," and the
+boys were wondering what new developments might take place, the shelling
+of Paris meanwhile continuing at intervals, that one evening the boys
+were visited in their lodgings by Major de Trouville.
+
+"Is there any news?" eagerly asked Tom, for he guessed that the French
+officer would not be paying a merely social call. Those were the
+strenuous days when such things had passed.
+
+"Well, yes, news of a sort," was the answer. "But what I came to find
+out was whether you were so taken with these lodgings that you could not
+be induced to move."
+
+"To move!" exclaimed Jack.
+
+"Yes. Have you found anything unhealthful here?"
+
+"Why, no," replied Tom, wonderingly. "We like it here. The landlord
+couldn't be nicer, and we're in a good location."
+
+"Nevertheless, I fear I shall have to ask you to change your quarters,"
+went on the major, and by the quizzical smile on his face the boys
+guessed that there was something in the wind.
+
+"Let me ask you another question," went on the French officer. "Have you
+been annoyed since you have been here?"
+
+"Annoyed? How?" inquired Tom.
+
+"By unwelcome visitors, or by strangers."
+
+The boys thought for a moment.
+
+"There's one chap who lives in the same building here, whom we've seen
+on our staircase several times," said Jack, slowly. "Once I saw him
+pause at our door with a key, as though he were going to enter, but he
+heard me coming, and, muttering that he had taken too much wine and was
+a bit hazy in his memory, he went on upstairs."
+
+"I thought as much," the major said. "Was the man you speak of familiar
+to you?"
+
+"No, I can't say that he was," replied Jack, and Tom nodded his
+acquiescence. "I never saw him before."
+
+"Oh, yes you have," and the major smiled.
+
+"I have? Where?"
+
+"On the train, coming into Paris."
+
+"You mean the German spy?" cried Jack.
+
+"The same," answered the Frenchman. "That's just what he is, and he is
+spying on you. Now, in view of what is going to happen, we don't want
+that to go on. So I have come to ask you to change your lodgings, and I
+think I can take you to one that will be most agreeable to you both."
+
+"But what does all this mean?" asked Tom. "Is there----"
+
+"There is 'something doing' as you say so picturesquely in the United
+States," interrupted the major. "I have come to tell you that you are to
+undertake a most perilous mission!"
+
+
+
+
+CHAPTER XIII
+
+THE SPY
+
+
+Tom Raymond and Jack Parmly looked first at one another and then at the
+major. He had been smiling at their wonderment, but he was now serious,
+and regarded them gravely.
+
+"Do you mean we have to do something to help catch this spy?" asked Tom.
+
+"I'd like a hand in that!" exclaimed Jack. "I saw him first--he's my
+meat!"
+
+"Well, get him if you can, boys," said the Frenchman. "But I did not
+come here to talk so much about him as about yourselves. The spy is a
+danger and a menace, but we know him and if he goes too far we can put
+out our hands and drag him back.
+
+"No, what I referred to is more dangerous than merely trying to catch a
+spy at his sneaking work. I will tell you." The major suddenly left his
+seat near the window of the boy's room, and quickly opened the door
+leading to the hall. The passage was empty.
+
+"I rather thought there might be an eavesdropper," the major explained.
+"I was followed here, though I don't believe the spies know my mission.
+However, it is best to be careful. With your permission I'll pull down
+the shade. There may be spies stationed across the street who, with
+powerful glasses, might look through the window and gather something of
+what we say by reading our lips. It has been done."
+
+"The Germans don't leave much untried," commented Tom. "But what is it
+you want us to do, if it isn't trying to trail the spy?"
+
+The major motioned them to draw closer to him, and then, leaving the
+door into the hall open, so that he could note the approach of any one,
+he whispered:
+
+"You are to be two members of a picked company of air scouts who are to
+go out, discover the big German gun, and destroy it!"
+
+"Whew!" whistled Tom, after a moment of thought during which he and Jack
+exchanged quick glances.
+
+"Well?" asked the officer. "How does that strike you? I believe that is
+another of your captivating terms?"
+
+"It's all to the good!" exclaimed Jack. "What say, Tom? We'll take that
+on, won't we?"
+
+"Well, I should say!" was the enthusiastic rejoinder. "When do we start
+to--"
+
+"Hush!" cautioned the major. "Not so loud. Though we have taken every
+precaution, there may be spies unseen by us. We had better talk no more
+about it here."
+
+"Then let's go to our new lodgings, if we are to move," suggested Tom.
+"Will it be safe to talk there?"
+
+"I think so," the major said. "At least you will be among friends. Not
+that your landlord here is not a true Frenchman; but he can not control
+the actions of those to whom he lets lodgings. You will be better where
+you are going. Then you accept the mission?" he asked in another
+whisper.
+
+"Sure thing!" answered Tom, while Jack nodded his assent. "The sooner
+the quicker!"
+
+"I do not quite get that," the major confessed with a smile. "But I
+think I gather your meaning. Now if you will proceed to this address,"
+and he handed Tom a small slip of paper, "you will find a comfortable
+lodging, and you will be among friends."
+
+"How soon can we start on--on this mission?" asked Tom.
+
+"It will be better not to refer to it directly," the officer said. "Talk
+as little about it as you can. But you shall go as soon as the
+arrangements can be made. You will be notified."
+
+"And what about seeing our friends--Mrs. Gleason?" asked Jack.
+
+"Are you sure its _Mrs._. Gleason you want to see?" inquired Tom.
+
+"Oh, cut it out!" advised Jack with a blush.
+
+"You may see them soon now," the major told him with a smile. "And I
+hope you'll soon have good news of your father," he added to Tom.
+
+"I hope so, too. The suspense is telling on me."
+
+"I should think it would. Now don't leave this bit of paper about with
+the address of your new lodgings on. Better commit it to memory, and
+then destroy the sheet. We want, if possible, to prevent the spy from
+knowing where you have gone. I will call a taxicab for you. You can be
+packed soon, I suppose?" he questioned.
+
+"Within a half hour," answered Jack. "But say, won't that spy be on the
+watch, and won't he learn from the taxicab driver where we have gone?"
+
+"Not from _this_ taxicab driver," was the smiling answer. "He is one of
+our best secret service men. But treat him as you would an ordinary
+chauffeur. You may even give him a tip, and he will not be offended,"
+and once more the major smiled.
+
+Tom and Jack, having made sure they remembered the address given them,
+destroyed the paper, and then proceeded to get ready to move. Meanwhile
+Major de Trouville took his departure, promising to keep in
+communication with the Air Service boys.
+
+Punctual to the half hour a taxicab appeared at the door. The boys
+obeyed the instructions they had received, and looked out to make sure
+the spy was not on hand. If he was, he was well concealed, for they did
+not see him.
+
+"Though I suppose he's somewhere around," said Jack.
+
+"Well, maybe we can fool him," suggested Tom. "We're going quite on the
+other side of Paris."
+
+They made sure that, as far as could be told by observation, there was
+no one resembling the spy around the place or in the street in front,
+and then got into the cab with their baggage. The chauffeur seemed not
+to know them, but Tom thought there was just the slightest wink of one
+eye, as though to indicate that the game was going well.
+
+Their cab was driven out along the Boulevard Ragenta, past the Gare du
+Nord, and across the Boulevard de Rochechquart to a small street running
+off the Rue Ramey, and there the cab stopped in front of a small but
+neat-looking house.
+
+"Quiet enough neighborhood," remarked Jack, as they got down, and Tom
+tipped the cabman for the benefit of any spies who might be looking.
+
+"Yes, I guess we can get some sleep here, if the big gun doesn't keep us
+awake," agreed Tom.
+
+On the way they had passed several places where the havoc of the
+"Bertha" was noticeable.
+
+Tom and Jack seemed to be expected, for the porter, who came down to get
+their bags, did not seem at all surprised to see them. He bade them
+follow him, and a little later, the cab having chugged off, the boys
+were settled in a pleasant room, a smiling landlady coming in to see if
+they wanted anything, and to tell them they could have meals with her at
+certain hours, or they might dine out as they pleased.
+
+"Your friends will be here shortly," she added.
+
+"Our friends?" questioned Tom.
+
+"Yes," with a nod and a smile. "I was told to say they would be here
+shortly after you arrived."
+
+"Oh, I guess she means the major and some of the officers will come to
+see how we are situated, and to tell us more about--the big stunt," said
+Tom in English to his chum, assuming that "big stunt" would sufficiently
+disguise to any listening spies, if such there were, the real object
+that lay before them.
+
+"I suppose that's who she means," agreed Jack, as the landlady, who gave
+her name as Madame Reboux, withdrew.
+
+The boys were busy unpacking their few belongings, for they had not
+brought much to Paris, not intending to stay long, when they heard
+voices in the hall outside their room. And at the tones of a certain
+voice Tom and Jack started and looked at one another.
+
+"Listen!" exclaimed Tom.
+
+"If I wasn't afraid you'd say I was dreaming, I'd say I knew that
+voice!" murmured Jack.
+
+"I'd say the same," added Tom.
+
+"Who would you say it was?" his chum challenged.
+
+"Well, for a starter--"
+
+He paused, for the voice sounded more plainly now, and it said:
+
+"Yes, this is the right place, Mother. Oh, do you think the boys are
+here yet?"
+
+"It surely will be a pleasure to meet them again," said another voice,
+evidently that of a woman, the other having been a girl's.
+
+"I hope they won't have forgotten us," the girl went on, and at that
+Jack could no longer keep quiet. He rushed to the door, opened it, and
+cried:
+
+"Bessie! Is that you?"
+
+"Oh, it's Jack! Mother, here's Jack!" cried the girl, and she and her
+mother were soon shaking hands with Tom and Jack.
+
+"So, you two were the friends we were soon to see!" exclaimed Tom, as he
+placed chairs for Mrs. Gleason and her daughter. Or, to be exact, Tom
+placed a chair for the mother, while Jack got one for Bessie.
+
+"Yes, we were told you would be here," said Bessie's mother. "We did not
+know you were in Paris until we received word that it would be better
+for us to change our lodging and come here."
+
+"The same word we received," said Jack. "Say, it's working out mighty
+queer, isn't it, Tom?"
+
+"Yes, but very satisfactorily, I should say. Things couldn't be nicer.
+How have you been?" he asked, for he had not seen the girl nor her
+mother since the sensational rescue from the perfidious Carl Potzfeldt.
+
+"Very well indeed," answered Mrs. Gleason. "Both Bessie and I have been
+doing Red Cross work. But isn't that great German gun terrible? Oh, how
+it has killed and maimed the poor women and children! The Huns are
+fiends!"
+
+"I quite agree with you," said Tom, Jack meanwhile talking to Bessie.
+"But it isn't doing them the military good they thought it would, and,
+if all goes well, it may not very long do them any service at all."
+
+"You mean--" began Mrs. Gleason.
+
+But just then Bessie, who had arisen to go to the window to view the
+street, turned back with a start, and grasped Jack's hand.
+
+"Look! Look!" she whispered, and through the curtains she pointed to a
+man on the opposite side of the way.
+
+"Do you know him?" asked Jack.
+
+"Know him? Yes, to my sorrow."
+
+"Who is it?" asked Tom.
+
+"The spy!" exclaimed Jack. "The man we saw in the train, and the same
+fellow who tried to get into our lodgings. In spite of our precautions
+he has found out where we are."
+
+"I'm not so sure of that," said Tom. "He may not be here for any
+particular purpose. But do you know him too, Bessie?"
+
+"Yes," the girl answered. "He was in the chateau where mother and I were
+held prisoners by Potzfeldt. He is a tool in the pay of that spy, and a
+spy himself!"
+
+"Then we ought to do something!" exclaimed Jack, and he started to rush
+from the room.
+
+
+
+
+CHAPTER XIV
+
+WITH COMRADES AGAIN
+
+
+"Hold on! Wait a minute!" exclaimed Tom, as he caught hold of his chum.
+"Where are you going?"
+
+"Out to give warning to a policeman or to some army officer about that
+spy!" exclaimed Jack. "We know him to be such, and now, with Bessie's
+word that he was with Potzfeldt, it's enough to cause his arrest."
+
+"Yes, maybe it is," agreed Tom, who was a bit more cautious than his
+impetuous chum. "But if we do that we may spoil the plans of Major de
+Trouville. Better let matters take their course, Jack. That spy may not
+know we are here, and again, he may. But if he doesn't, rushing out now
+would be sure to give the secret away. As it is, there is a chance we
+may keep it."
+
+Jack, caught midway in his impetuous rush from the room, stood
+reflectively. What Tom had said to him appeared to make an impression.
+Then Bessie added her words of advice.
+
+"Yes, Jack," she said, "I think it would be rather rash to go out now
+and confront that man, or start a chase after him. I know I'm not as
+experienced as you two famous birdmen," she went on with a smile, "but
+I've been through some terrible experiences, as almost every girl has in
+this war zone, and I can do more thinking than I used to. Don't you
+think it would be wise to wait, Mother?"
+
+"Yes, Bessie," answered Mrs. Gleason, "I do. Our good friends in the
+military service who told us to come here, must have had some object.
+Perhaps it was connected with this same man who was so unkind to us in
+the chateau, and who was certainly a tool of that man I trusted once,
+but never will again--Carl Potzfeldt!" and she shuddered as she thought
+of what she had gone through.
+
+"Let him go," she said to Jack. "Perhaps it is just a coincidence that
+he is passing just as we arrive. Our departure from our last lodgings
+was made secretly."
+
+"So was ours," said Tom. "And yet I don't see how that spy found us so
+soon."
+
+"It is that which makes me think it is accidental," observed Mrs.
+Gleason. "It would be very unwise now to go out, I think."
+
+"All right, then I'll stay in," said Jack with a smile. "Especially as I
+have such good company. Tell me," he went on, "are you and your mother
+going to board here?" he asked Bessie.
+
+"Yes," answered Mrs. Gleason. "And though we were told we would meet
+friends here we could not guess it would be you brave boys."
+
+"Spare my blushes!" laughed Tom.
+
+"Same here," added Jack.
+
+"But what brings you to Paris?" asked Bessie. "I thought you boys were
+engaging in combats above the clouds."
+
+"We have been fighting, though not during the last two weeks," said Tom.
+"I had word that my father had come over here, but he never communicated
+with us, and we came to Paris to look him up. So far we haven't
+succeeded in finding him," and he gave the details of the visit of
+himself and his chum to the capital, telling of their first experience
+during the firing of the big gun.
+
+Bessie and Jack, who seemed to have much to say to one another, peered
+from behind the curtains out of the window now and then, and Jack at
+last reported that the spy had passed on, after stopping, apparently, to
+purchase some fruit at a stand on the street.
+
+"I don't believe he knew we were here," said Bessie.
+
+"Well, it won't do to take any chances," observed Tom. "However, we were
+not told to remain under cover, so I suppose we can go out when we
+like."
+
+"Better wait until we get some word from the major," suggested Jack, who
+was getting some of his chum's caution.
+
+All decided this was best, and the boys spent the rest of the afternoon
+in getting their room to rights, Mrs. Gleason and Bessie doing the same
+in their apartment. Mrs. Gleason had temporarily been relieved from Red
+Cross work to recuperate, she said, as she had been under a great
+strain.
+
+Toward evening Major de Trouville, or "Trouville," as he democratically
+liked to be called, arrived, and when told of the sight in the street of
+the spy, who turned out to be the same man who was one of the captors of
+Bessie and her mother, the officer said:
+
+"I am not surprised. In fact I rather looked for that, and it is one
+reason why I wanted to get you four together so you could see the man at
+the same time.
+
+"There is now no doubt as to his intentions, and the fact that he was
+here so soon after you arrived proves that there is a 'leak' somewhere.
+We suspected as much, and I think I know where it is. It is good
+information to have. Well, boys, did I surprise you?" he asked, smiling.
+
+"You did, indeed, but it was a pleasant surprise," said Jack.
+
+"But when are we going to be allowed to do something to silence that
+monster cannon?" asked Tom. "It's pleasant to be here, but we are not
+forgetting there is work to do."
+
+"Nor would I have you forget," said the major. "A number of persons were
+killed to-day by fire from the long-range gun. We believe, now, that
+there are two or three of them, as the shots come at closer intervals.
+It is imperative that something be done, and so I have brought you
+orders."
+
+"Good!" cried Jack.
+
+"That sounds like business!" commented Tom.
+
+"In regard to your father," went on the major, addressing Jack's chum,
+"we will be on the watch for him, or any news of him, and, no matter
+where you are, unless you are captured by the Germans, you shall be
+informed as soon as possible."
+
+"Is there any chance of being made prisoners?" asked Jack, and it might
+be noted that he did not use the word "danger."
+
+"There is always that chance for an airman," replied the major. "But
+when I add that it may be possible that one or both of you will take a
+flight over the Rhine, you can judge, with the hold Germany has on
+French possessions, what the danger is."
+
+"Over the Rhine!" exclaimed Tom. "Why, that's a flight of two or three
+hundred miles from Paris."
+
+"Yes, but with the new type of Italian plane which you may use, it is
+not impossible in a single flight," said the major. "However, we will
+talk of that later. Just now I have come to tell you that you are to
+rejoin your comrades at the Lafayette Escadrille for a time. There
+arrangements will be made for the perilous venture I spoke of--the
+silencing of the big guns that are bombarding Paris. I wish you all
+success, young gentlemen."
+
+"Thanks," murmured Jack.
+
+"We consider it an honor to be picked for such duty," added Tom. "Are
+any others going to be in the game?"
+
+"Oh, yes. We shall need a picked corps of the best airmen we have,
+French and Americans, and it will be no easy matter then. The Germans
+have probably been planning this for a long time, and they, no doubt,
+have taken every possible precaution against surprise or failure. But
+with the help of you brave Americans we shall win!"
+
+"That's right!" chimed in Bessie. "Oh, how I wish I were a man!" and she
+looked enviously at Jack and Tom.
+
+The major gave Bessie and her mother some instructions in regard to
+their actions should the spy come back, and then told Tom and Jack to
+prepare to leave Paris the next night.
+
+"Report to your former camp," he said, "and there you will find further
+instructions waiting for you."
+
+"Well, then as we have to-night, our last one free, let's go to some
+entertainment," suggested Tom to Bessie and her mother. "We can have
+supper afterward--not much of a celebration, for these are war times and
+it won't do to rejoice too much. But we ought to commemorate this
+meeting somehow."
+
+"That's right!" agreed Jack.
+
+So they went to a little play and had supper afterward in a quiet
+restaurant. That is, it was quiet until a sudden explosion a few blocks
+away announced the arrival of another German shell from the big gun, and
+then there was excitement enough.
+
+Fortunately, however, the shots did little beyond material damage, no
+one being killed. At the same time, however, there appeared some German
+planes over Paris, doubtless to observe the effect of the dropping of
+the long-distance shells, and naturally the French airmen went up to
+give them combat.
+
+The great searchlights began to play, picking out the hostile craft, and
+making them targets for the machine guns of the intrepid Frenchmen, and
+more than one Boche never got back over his lines again, while several
+Frenchmen found heroes' graves on the soil they had died to defend.
+
+"Oh, if we were only up there helping," said Tom, as he and his friends
+watched.
+
+"We shall be there very soon," murmured Jack. "And it can't be any too
+soon for me."
+
+The tide of battle turned in favor of the French, the Hun planes
+withdrawing as the fire got too hot for them. And soon after that the
+long-range gun ceased firing.
+
+It was rather a "pull" for Tom and Jack to say good-bye to Bessie and
+her mother in Paris, but they knew they had to do their duty. Nor would
+Mrs. Gleason and her daughter have kept the boys back for the world.
+They realized that the Air Service boys were helping to make the world
+safe for democracy, as they themselves were doing in their way.
+
+And so Tom and Jack, their mission to Paris, which was the discovery of
+Mr. Raymond, having failed, went back to the hangars, there to be
+welcomed by their comrades in arms.
+
+They arrived one morning, just after some planes from a bombing
+expedition over the German lines returned.
+
+"What luck?" asked Tom of a pilot with whom he had often flown.
+
+"The best, as regards the damage we did," was the answer. "We blew up
+several ammunition dumps, and put one railroad center out of business
+for a time. But Louis didn't come back," and the man turned aside for a
+moment.
+
+"You mean your brother?" asked Jack, softly.
+
+"Yes."
+
+"Perhaps he is only captured," suggested Tom.
+
+"No, his machine caught fire. They got his petrol tank. It's all up with
+him and La Garde. But we had our revenge. We sprayed the machine that
+got them until there was nothing left of it. And I'm going out again
+to-day in a Nieuport. They'll pay a price for Louis!"
+
+
+
+
+CHAPTER XV
+
+THE PICKED SQUADRON
+
+
+"All ready, Jack?"
+
+"Just a moment, Tom. I want to go over my struts and wires to make sure
+everything is taut. I don't want any accidents."
+
+"That's right. Got plenty of ammunition drums?"
+
+"All I can carry. I've got some tracer bullets, too."
+
+"That's good. Glad you reminded me of them. I must put in a stock. The
+last time I went up I wasted a drum before I got my man."
+
+Tracer bullets for aircraft guns, it might be observed, are balls of
+fire which enable the pilot to see the course his machine gun bullets
+are taking, so he may correct his fire.
+
+"Well, how about you now?" asked Tom, as he added these useful supplies
+to his ammunition.
+
+"I guess we're ready to start," replied Jack.
+
+They climbed into their machines, each pilot using a single-seat,
+swift-flying craft, equipped with a Lewis machine gun. The squadron was
+going out on patrol duty, and each pilot was to observe what he could
+behind the German lines, and come back to report--that is if he did not
+happen, as was too often the case, to be bagged by a German flier. The
+small, swift machines did not carry the wireless outfit, and no reports
+could be sent back to headquarters save those the pilot himself came in
+with.
+
+There was a rattle and a roar as the motors of the ten machines started,
+and then over the ground they went, "taxi fashion," to get the necessary
+speed to rise into the air. A moment later all went aloft, and were
+headed toward the German lines.
+
+Tom and Jack kept as close together as was safe, but it is dangerous for
+two aeroplanes to approach too closely. If they do, and are not under
+good control, there may be a suction created that will cause a
+collision.
+
+"Well, I hope I get one to-day," thought Tom, as he manipulated his "joy
+stick," so as to send his plane up on a sharp slant. "I want to make
+good, and then I'll have so much better chance to get after that German
+gun." And the same thought was in Jack's mind.
+
+The squadron was to remain aloft on a two-hour patrol, that is unless
+something should occur to make it advisable to remain up longer. The
+keen eyes of Tom and Jack, as well as those of their companions of the
+air, were searching for signs of the Hun planes. As yet none were in
+sight, but it would not be long before they would come out to give
+battle.
+
+Whatever else may justly be said about the Germans, their airmen are no
+cowards, and, when conditions are favorable, they seldom decline a
+chance to combat above the clouds, or lower down. So it could easily be
+guessed that when Tom, Jack and the others found themselves over the
+German lines that the Boches would be out in force.
+
+Somewhat off to the left Tom caught sight of a captive German balloon,
+looming through the mist, and as it is always the desire of a French
+flier to destroy one of these, thus preventing the observer from sending
+by wireless news of the Allied front, he started for this enemy. Jack
+saw his friend's act, and, desiring to aid, turned his machine in the
+same direction.
+
+But they had not gone far before they observed a number of black specks
+in the sky over the German lines.
+
+"The Huns are coming," reflected Tom. "Now for some hot work."
+
+And it came to him, to Jack, and the others, almost before they realized
+it. Tom never got a chance to attack the balloon he hoped to force to
+descend or to set on fire, for his attention was taken up by two German
+machines, which, separating from the others, headed straight for him.
+The lad gave one glance in the direction of Jack, and noted that a
+single Hun craft was about to engage with his chum.
+
+"It's a regular German circus," thought Tom, referring to the number of
+hostile craft. "They delight to go out in numbers."
+
+By this time the battle in the air had begun. It was a fight above the
+clouds, for both the French and the German machines were flying high,
+and had gone up above the bunches of fleecy vapor that now hid the
+ground from sight.
+
+Tom headed straight for one of the Hun machines, seeking to get above
+it, always a point of vantage in an air battle, and as he rushed on he
+realized that his machine was being hit by bullets from one of the Hun
+guns.
+
+Each bullet, as it struck, made a loud noise, as it punctured the
+tightly-drawn linen that covered the wings. But Tom knew that his craft
+could stand a number of such holes, if only the struts, the supports,
+and the guy wires were not broken. He had no time, now, to note what
+Jack or his comrades were doing, for his whole attention was taken up
+with the two Hun machines engaging him.
+
+One seemed to be more skillful than the other, and to this one Tom gave
+his attention first. He emptied a stream of bullets full into this
+flier's craft, noting, after the first few bad shots, which he could
+tell by the tracers, that he had perfect range.
+
+Guiding his craft with one hand and his feet, Tom worked the Lewis gun
+with his other hand, and he had emptied a whole drum at the daring Hun
+before he had the satisfaction of seeing the machine crumple up. Tom's
+bullets had struck some part that had caused the wings to collapse, and
+the airman went down to earth, his craft out of control.
+
+But matters were not to go easy with the American. The other German was
+now in a better position for getting Tom than the latter was for potting
+him, and Tom felt a stream of bullets flying around him. One chipped his
+gun, and another grazed his cheek, the close call making his heart stand
+still for a moment. But he never faltered.
+
+"I've got to get above him," Tom thought fiercely.
+
+He made a risky spiral turn to one side, and began to mount, seeking to
+get in position to fire to better advantage. It was touch and go for a
+while, and he felt, rather than heard, his craft receive several
+bullets.
+
+"If only the gasolene tank isn't hit," thought Tom.
+
+But good fortune in this respect was with him, and he got in a position
+where he could point his machine (and the gun at the same time, for this
+is how the guns are aimed in the single aircraft) at the Hun flier. And
+then Tom sent forth a rain of bullets.
+
+For a moment they seemed to have no effect, and yet Tom knew he had shot
+straight. Then, even while he felt a sharp pain in one hand, showing
+that he had been hit, he saw the other machine start down in a spinning
+nose dive. That meant he was going downward head first, and at the same
+time spinning around like a top.
+
+This spinning nose dive may be intentional or accidental--that is, with
+the machine in control, or out of control. The spinning nose dive was
+discovered by accident, but is now part of the regular flying features,
+and is often used by aviators to escape from an enemy.
+
+It is almost impossible to hit a plane doing a spinning nose dive, and
+if an aviator is over his own lines he may be able to come out of it
+before he reaches the ground, and so be safe. Many German planes have
+escaped in this way, and often a French airman has thought he has sent
+his enemy down disabled, when, as a matter of fact, the other has merely
+adopted this ruse to get away.
+
+"Well, I don't know whether I got him, or whether he got frightened and
+went down to fool me," thought Tom. "Anyhow they're both out of the way,
+and I can go after the balloon."
+
+But Tom could not, for two reasons. One was that the wound in his hand
+was bleeding profusely, and he knew it ought to be attended to before he
+was incapacitated. Another was that the balloon was being hauled down,
+and as more French planes were in the air now, making a number superior
+to the Huns, the latter turned tail and retreated.
+
+It was inadvisable to follow them over their own lines now, and the
+squadron, or what was left of it, began to retreat. Tom noted the
+absence of three of the French planes, and among the missing was Jack's.
+
+"I wonder if they got him," Tom mused, his heart becoming like lead. His
+eyes sought the air about him, but Jack's machine, which carried a
+little United States flag where it could easily be seen, was not in
+sight.
+
+It was impossible to get any information up in the air. Tom would have
+to wait until they got back to the aerodrome. And he put on speed to get
+there the sooner, in order to end his suspense.
+
+"And the other brave fellows--I wonder what happened to them," mused
+Tom. In his worry over the fate of Jack and the others he scarcely
+minded the pain in his hand.
+
+He made a good landing, but being rather weak and faint from loss of
+blood, he scarcely heeded the congratulations of his comrades, who had
+received word, by telephone from the front, of the fate of some of the
+Hun machines. "Where's Jack?" Tom gasped, while a surgeon was putting a
+bandage on his hand.
+
+"Right here, old scout!" came the unexpected answer, and Jack himself
+stepped out from amid a throng of airmen. "Why didn't you wait for me?"
+Jack went on. "I was coming back."
+
+"Coming back? Did you come down safely?" asked Tom, beginning to feel a
+little better now. Then Tom realized the futility of his question, for
+was not Jack there in the flesh?
+
+"Of course I came back, old scout," was the answer. "I had hard luck,
+though, but I'd have gone up again if they'd only waited for me."
+
+"What happened?" asked Tom.
+
+"Oh, just after I potted my man--or at least sent him down out of
+control--I got a bullet through my gasolene tank. Luckily it didn't set
+the petrol on fire, but I knew I'd better not take any chances. I tried
+to plug up the puncture with some chewing gum, but it wouldn't work.
+Guess the gum they sell now hasn't as much old rubber boot stock in it
+as it used to have. Anyhow it was leaking like a sieve, and I had to
+head for our lines."
+
+"Tough luck!" consoled Tom. Jack did not add that he had, as soon as he
+landed, got into another machine, and was about to go back and join his
+comrades when they returned, having practically won the battle above the
+clouds.
+
+Congratulations were extended to the members of the squadron, who
+accepted their honors modestly enough, as was characteristic of them.
+
+Then, after Tom's wound had been dressed, and he and Jack were talking
+over the events of the day, there came a communication from the
+commander of the air division in that sector. It was an order calling on
+certain men to report at once for special duty. A picked squadron was to
+be detailed for a hazardous enterprise, it was said.
+
+"And our names are there!" cried Jack. "Tom, old man, we're going!"
+
+"But where is it?" asked another American flier named Boughton. "What's
+the game?"
+
+Knowing the secret would be safe with him Tom said:
+
+"We're going to pot the big German cannon that's bombarding Paris!"
+
+
+
+
+CHAPTER XVI
+
+MISSING
+
+
+News of the shelling of Paris by the long-range gun had, of course, been
+received at the aerodrome, though there had not, as yet, many details
+come in. Tom and Jack, as the latest arrivals from the big city, were
+called upon to tell all they knew, and they related their experiences in
+the raids, and also told about the various theories of the big gun.
+
+"But how are we going to find it?" asked. Boughton. "It's easy enough,
+of course, for our squadron to go out with a lot of bombs. But where are
+we going to drop 'em?"
+
+"Oh, we're to go to Paris for further instructions before starting on
+the quest," said Tom, who had made some inquiries about the orders
+concerning the picked squadron.
+
+"And they may have discovered its location by this time," added Jack.
+"We know about where it is--somewhere in the sector between Hamegicourt
+and Conde. The rest ought to be easy."
+
+"Not so easy as it sounds, my friends," put in a French flier. "I know
+that region. It is a big one; and the Germans no doubt have their gun
+well camouflaged. It will not be easy."
+
+"But we'll get it!" asserted Tom.
+
+"Naturally," said the Frenchman, as if that was all there was to it.
+
+Tom's wound was painful, but not dangerous, though it would keep him on
+the ground for a day or two. Though, as a matter of fact, none of the
+members of the picked squadron was allowed to go aloft after the orders
+came detailing them for work in connection with the monster cannon.
+Their places were taken by others who were sent for, some being new
+fliers who were burning to make a name for themselves.
+
+Besides Tom and Jack, in the picked squadron there were Boughton,
+another American, Cerfe and Tierse, two intrepid Frenchmen, and Haught,
+an Englishman, who insisted, but with little success, that his name be
+pronounced as though spelled "Hoo."
+
+These six were to be depended on to find and destroy the German
+cannon--all of them if there were more than one, as was likely. And to
+this picked squadron other members would be added as need arose. All six
+were skillful fliers, and brave men of the air, as may easily be
+guessed. They were to use whatever type of machine they liked best--the
+single seaters, the great bombing planes, and, it was even said, one of
+the immense Italian fliers. This last was a craft capable of carrying
+several men and a quantity of supplies and ammunition.
+
+Very soon, then, Tom Raymond and Jack Parmly were on their way to Paris
+again, accompanied by their comrades, and all would soon be engaged in
+the difficult and perilous task of finding the new German long-range
+cannon.
+
+"I suppose you'll make another attempt to find your father?" suggested
+Jack to his chum, as they rode in on the train.
+
+"Indeed I shall, if I have time. I can't understand why I haven't had
+some word before this. There are several possible reasons, of course. If
+it wasn't that we know he got to Rue Lafayette I'd say his ship had been
+sunk 'without a trace,' as the Germans ordered in other cases. But, of
+course, he safely reached this side. Then he just seems to have dropped
+out of sight, for I can't believe he was killed when the shell from the
+big gun hit the house where he had taken lodging. He may have found it
+advisable to return home at once, for some reason, and didn't have a
+chance to leave any word for me, or send me any message. And perhaps he
+hasn't got back to America yet. Then, too, he may be in Germany, a
+prisoner."
+
+"Let us hope not," said Jack, softly, and Tom echoed the wish.
+
+Much as he wished he could devote some time to the search for his
+father, Tom realized that he was working under military orders, and,
+however dear his father was to him, the sacrifice of his personal
+affairs must be made. He knew he would only have time to make some brief
+inquiries, and then he and Jack must go with the squadron to the
+headquarters assigned to it, as near the location of the big German gun
+as possible, and there try to silence it.
+
+The train the picked squadron was traveling on was late, and it was dusk
+when they alighted at the railroad station.
+
+"Think we'll have a chance to see anything of the bombardment?" asked
+Boughton.
+
+"I was going to say I hoped not," answered Tom, "for I wish the beastly
+gun, or guns, would blow up. But that would take away our chance to pot
+'em, and I know we all want to do that. You may see something, though
+they don't bombard at night as often as they do by day. Of late,
+however, before we left, the night firing was more frequent. Possibly
+they have found some means of hiding the gun flashes or of letting them
+mingle with others along a line so the exact location of the big Bertha
+is a matter of doubt."
+
+As they alighted from the train, and were about to seek some taxicabs to
+take them to lodgings that had been assigned them, they all became aware
+of the fact that something unusual was going on. Suddenly the electric
+lights went out, leaving the region about the station, and indeed all of
+Paris, in comparative darkness.
+
+At the same time a motor fire engine rushed screeching through the
+streets, giving an alarm.
+
+"What is it?" cried Boughton. "Is the big gun firing?"
+
+"It's a Zeppelin raid! I was here once before when they had one," said
+the Englishman coolly. "Mind your heads, boys. Just our rotten luck not
+to have a machine to go up after it."
+
+He hurried out into the open street where he could have a view of the
+sky, and the others followed. There was more excitement than during the
+bombardment of the big gun. People were rushing here and there in search
+of safe places, and taxicabs, with their lamps like fireflies in the
+darkness, were skidding hither and yon, their horns calling for a clear
+way.
+
+Suddenly there was a muffled roar, at some distance off. This was
+followed by a hoarse murmur, as though a burst of rage from many throats
+at the unspeakable outrage of the Huns in killing women and children.
+
+At the same time the anti-aircraft guns, with which Paris is so
+efficiently guarded, began to bark and to send their red flashes out
+into the blackness of the night. They were shooting at the Zeppelin, as
+yet unseen by the men of the picked squadron, and the gunners aimed
+according to instructions sent them by wireless from scouts hovering in
+the air above the city.
+
+As soon as word comes from the front, about eighty miles from Paris,
+that a Zeppelin is on its way to raid, an elaborate system of defense is
+put into operation. There are some airmen above Paris all the while,
+frequently as many as forty on sentry duty. But when word comes of a
+Zeppelin raid the whole squadron, numbering close to three hundred, goes
+aloft. By their searchlights, aided by those on the surface, these
+fliers endeavor to pick up the German machine, and, too, they endeavor
+to get near enough to attack it.
+
+This was what was now going on. Pandemonium appeared let loose, and the
+explosion of the German bombs, mingling with the noise of the French
+guns, made Paris seem like a battlefield. Occasionally could be heard,
+when the guns were silenced for a moment, the roar of the many aeroplane
+motors aloft.
+
+The Zeppelin seemed to be over a section of Paris near the Tuileries,
+judging by the bursts of light in that direction. Tom, Jack, and their
+friends wished with all their hearts that they might take a hand in the
+defense, but it was not to be. For perhaps half an hour the
+anti-aircraft guns roared out their defiance to the Hun, and then a
+large flare of gasolene was lighted in a public square.
+
+This was a signal for the aeroplanes to return, for the Zeppelin had
+left, either because she found the situation too perilous for her, or
+because she had used up all her bombs.
+
+The lights were turned on again, and the new arrivals watched the
+aeroplanes returning one by one, being recognized by their lights in the
+air as they moved about like gigantic illuminated insects.
+
+"Well, that's some excitement," observed Tom, as he and the others
+finally succeeded in getting cabs, and started for their destination. "I
+hope no one was killed."
+
+But the bombs of the inhuman Huns had found several marks, and while the
+harm from a military standpoint was small, a number of persons had been
+killed. Some damage had been inflicted on the Zeppelin, it was said
+later, one brave airman saying he got near enough to spray some bullets
+into one of the cabins where a crowd of officers and men were working
+the machine.
+
+"We will be with you a little later," said Tom to the other members of
+the squadron, as, having reached their lodgings, the two chums set out.
+
+"Where are you going?"
+
+"To call on some ladies," answered Jack, for he and Tom had planned to
+see Bessie and her mother.
+
+They reached their own former stopping place, to which they had been
+sent by Major de Trouville, but when they inquired for the Gleasons the
+landlady, who remembered the boys, stared at them in surprise, and said:
+
+"Why, Madam Gleason and her daughter are not here! They went out this
+morning to meet you, and have not come back!"
+
+"To meet us?" gasped Jack.
+
+"Yes, in answer to your note bidding them do so!"
+
+
+
+
+CHAPTER XVII
+
+SEEKING THE GUN
+
+
+Tom and Jack gazed blankly at one another. The same thought was in the
+minds of both.
+
+"The spy!"
+
+"That's who did it," declared Tom. "He forged our names to a note--no
+hard task since neither Bessie nor her mother knows our writing very
+well--and he's induced them to go some place where he could get them in
+his power again."
+
+"But why?" asked Jack.
+
+"Probably because Potzfeldt wanted him to do it. He still has his eye on
+Mrs. Gleason's property, I presume, if there is any left after his
+robbery."
+
+"It certainly is tough to think that Bessie and her mother have again
+fallen into his clutches!" exclaimed Jack. "And we can't do a thing to
+rescue them. We've got to report with the others in the morning at the
+new aerodrome."
+
+"Yes, but we still have to-night free!" cried Tom. "It will give us
+several hours to make a search, and we'll do it! Do you know where Mrs.
+Gleason and Bessie went in response to this forged note?" he asked the
+landlady.
+
+She mentioned a certain restaurant, not far away, where Tom and his chum
+had frequently eaten with Mrs. Gleason and her daughter.
+
+"She was rather surprised to get the note from you," said the landlady,
+"and wondered why you didn't come yourself. But she supposed it had
+something to do either with your search for your father or with war
+matters, so she did not question the messenger. I heard her mention the
+place where she and Bessie were going, or I would not know."
+
+"How long ago was it?" asked Jack.
+
+"Oh, just before luncheon time. And they haven't come back."
+
+"The scoundrels have a long start of us!" exclaimed Jack. "We'll have to
+do the best we can."
+
+"Better notify the police at once," suggested Tom. "We'll need their
+help."
+
+"That's right," agreed his chum.
+
+Their uniform was an open sesame to the police officials, and a
+detective was at once detailed to go with the boys to the restaurant.
+There, as might have been expected, there was no news. The spy, or
+whoever Potzfeldt's agent was, had been too clever for that. All that
+could be learned from a taxicab driver was that a lady and a girl,
+answering the descriptions of Bessie and her mother, had been met in
+front of the restaurant by a man.
+
+The three, after a short talk, had driven off together in an automobile,
+and that was the last seen of them.
+
+"But we'll get some trace," declared the detective. "It is hard to get
+in or out of Paris now without proper papers. And while, of course, this
+spy may have forged documents, there is a chance that we may intercept
+him and help your friends. Time is against us, but we will do our best."
+
+Tom and Jack knew that. There was nothing else to do, and so, worried as
+they were, they went back to their comrades. Tom made some inquiries
+about his father, but, as he feared, no news had come.
+
+As may be imagined Tom and Jack did not pass a very restful night. The
+Zeppelin raid had set their nerves on edge, as well as those of every
+one else, and it could not be told when the big gun might begin firing
+again. Then the fact of Mrs. Gleason and Bessie being missing, and not
+knowing in what danger they might be, added to the boys' anxiety.
+
+They paid a late visit to the police, hoping for news, but the spy had
+not been apprehended. Then they hurried back to get a little rest
+before starting with their comrades of the air to search for the monster
+gun.
+
+While these events were transpiring, the French army intelligence
+department had not been idle. The officials knew how vitally necessary
+it was, in order not to have the morale of the people of Paris weakened,
+to do something to find and silence the big guns. And first it was
+necessary to discover them.
+
+While this, as yet, had not been done with exactness, owing to the
+concealing tactics of the Germans, it was believed that the long-range
+cannon was hidden in a certain wood near Laon. French airmen had
+endeavored to spy out certain positions there, but an unusually large
+number of German planes had fought them off.
+
+"That's pretty good evidence that there must be something doing,"
+observed Tom, when he heard this information. "Laon is about ten miles
+behind the German lines as they exist at present. Just a breather for a
+good French plane. Jack, that's a trip we'll soon be taking."
+
+"I'll be with you, old scout. How's your hand?"
+
+"Oh, all right now. I can hold the joy stick or work the gun. I'm ready
+for whatever comes along."
+
+The time had come for the picked squadron to leave Paris and assemble
+at the aerodrome assigned to them as their headquarters while the search
+for the big gun was in progress. Sad at having to leave without having
+some word of Mr. Raymond, and without knowing the fate of Bessie and her
+mother, Tom and Jack, nevertheless, bore up well and left with their
+comrades, going out of Paris on a train that would eventually bring them
+to their headquarters.
+
+In a way their mission was a secret one. Yet it was a question if the
+Germans did not guess that something like what really was afoot would be
+undertaken in order to silence the super-cannon. They were up to all the
+tricks of war, and they must have realized that the French would do as
+the Germans themselves would do under similar circumstances.
+
+"Well, this sure is some place!" exclaimed Tom, as they reached the camp
+where they were to stay until the gun had been destroyed, or until some
+other change in plans was necessary. "It's the best aerodrome we've
+struck since we began flying in this war."
+
+"I believe you!" echoed Jack.
+
+The place, though newly established just back of the French lines, where
+they opposed the German trenches, was well fitted up for the purpose to
+which it was to be devoted.
+
+There were a number of canvas hangars for the aeroplanes, there were
+living quarters for the men, a wireless station and a well defended camp
+where the aviators might live in comfort during the periods between
+their flights.
+
+Of course the place was open to attack by German fliers, but this was
+true of every place along the line. Sufficient camouflaging had been
+done, however, to render the spot reasonably secure from bombing. Of
+course a direct attack from in front would be met by the admirable
+French system of defense, and there were plenty of reserves that could
+be brought up if a general advance were attempted by the Germans. But as
+there was no particular place of any military or strategic importance on
+that sector, the worst that was to be feared was an attack from the air.
+
+And this would be guarded against both by the French fliers themselves
+and by a battery of the newest type of anti-aircraft gun.
+
+"They don't seem to have forgotten much," observed Tom, as he and Jack,
+with the others, went to the quarters assigned to them.
+
+"You said something!" exclaimed Jack, admiringly.
+
+Thus had been set up in this locality, where heretofore no aircraft
+activities had been carried on to any extent, a most perfect
+escadrille.
+
+It was designed to destroy the big German cannon. Would it succeed?
+
+That was a question every man of the Allies asked.
+
+Shortly after the arrival of the picked squadron at the camp, which, in
+honor of Tom and Jack had been named "Lincoln," word came in over the
+wireless that the big gun had again fired on Paris.
+
+"It's funny we didn't hear any report of it," said Jack.
+
+"There have been reports enough," Tom remarked. "I've heard the booming
+of distant guns ever since we got near this place. Any one of them may
+have been the monster, or they may have been firing other guns to hide
+the sound of this cannon. Then, too, it may not make as much noise as we
+think it ought to. The Germans may have found a new kind of powder, or
+even some propelling gas, that makes no extraordinary report. In that
+case we couldn't locate the gun by the sound."
+
+"Maybe you're right," agreed Jack. "Anyhow they're firing, that much is
+proved; and it's somewhere over there," and he motioned toward the
+German lines.
+
+Much as the airmen desired to start at once in their search for the
+monster cannon, it was deemed wise to have first a consultation and a
+general understanding of what means should be employed.
+
+Then, too, all the aircraft were new, having been shipped to Camp
+Lincoln and there assembled, and it was desired to test them before
+taking the dangerous flights over the German lines. So the airmen would
+have to spend some time--perhaps half a week--in preliminary work.
+
+Meanwhile the great cannon would keep up its deadly, though, from a
+military standpoint, useless work.
+
+And so began the preparation, if such it might be called. Every one,
+from the most daring "ace" to the humblest kitchen helper in the camp,
+was anxious for the day when it could be said that the gun was out of
+commission, or guns, if, as was likely, there was more than one. But the
+men in command knew the value of thoroughness. There must be no failure
+through lack of making proper plans.
+
+But at last everything was in readiness. The planes had been tested,
+keyed up, and the motors run until every part of them was humming like a
+top. Each man felt confidence, not only in himself but in his craft, and
+that meant much. There were several types for the fliers to use,
+single-seaters, the big bombing craft, those equipped for slow flying
+and from which photographs were to be taken, as well as others. The
+taking of photographs was expected to help in revealing the position of
+the hidden gun.
+
+The big Italian plane was not ready, it seemed, to be used, but it would
+be soon, it was said.
+
+Then came the day and the hour when certain members of the picked
+squadron were to take the air to look for the gun. Tom and Jack, to
+their delight, were selected to go.
+
+"What a chance!" exclaimed Jack, as he climbed into his machine, and saw
+that he had plenty of ammunition for the Lewis gun.
+
+"I hope we can make good!" returned Tom.
+
+Then they were away and up, seeking to find the monster cannon that was
+bringing the war into the heart of Paris.
+
+
+
+
+CHAPTER XVIII
+
+A CLOUD BATTLE
+
+
+For some little time the picked squadron that was intrusted with the
+difficult and dangerous task of locating the big German gun flew over
+the French lines. Below them Tom and Jack could make out various French
+camps, the front and supporting lines of trenches, and various other
+military works. They could see a brisk artillery duel going on at one
+point. They noted the puffs of smoke, but of course could not hear the
+explosions, as their own motors were making too much noise.
+
+Tom and Jack kept within sight of one another, and also within view of
+their comrades. Each plane was marked with a big number so it could be
+distinguished, for the aviators themselves were so wrapped in
+fleece-lined clothes, so attired in gauntlets, goggles and fur boots, as
+protection against the terrible cold of the upper regions, that one's
+closest friend would not recognize him at a near view.
+
+It was the object of this first scouting expedition to make a
+preliminary observation over as wide a range of the enemy's country as
+possible. While it was hoped that the location of the big gun might be
+spied out, it was almost too much to expect to pick out the spot at the
+first trial. The Germans were keen and wary, and undoubtedly they would
+have laid their plans well.
+
+"Well, I don't see any of 'em coming out to dispute our passage,"
+thought Tom, as he looked at his controls and noted by his height gage
+that he was now up about two miles. "There isn't a Boche plane in
+sight."
+
+And the same thing was observed by Jack and the other fliers. The
+Germans seemed to be keeping down, or else were higher up, or perhaps
+hidden by some cloud bank.
+
+That was another hazard of the air. Going into a cloud, or above it
+might mean, on coming out, that one would find himself in the midst of
+enemies.
+
+It is a life full of dangers and surprises. It is this which makes it so
+appealing to the young and brave.
+
+On and on flew the Allied planes, and the eager eyes of the pilots were
+alternately directed toward the earth and then ahead of them, and upward
+to discern the first sight of a Hun machine, if such should venture out.
+
+The fliers were now well over the German lines, and the batteries from
+below began firing at them. This was to be expected, and Tom, Jack and
+the others had gotten used to the bursts of shrapnel all around them.
+They could see the puffs of smoke where the shells burst, but they could
+hear no sounds.
+
+"The 'Archies' are busy this morning," thought Jack, as he noted the
+firing from below, and using the French slang word for the German
+anti-aircraft guns.
+
+He took a quick glance toward Tom's machine to make sure his chum, so
+far, was all right. Assured on this point Jack looked to his own craft.
+
+"Well," he mused, "at this point the 'flaming onions' can't get us, but
+they may pot us as we go down, as we'll have to if we want to get a good
+view of the ground where the big gun may be hidden."
+
+The "flaming onions," referred to by Jack, were rockets shot from a
+ground mortar. They have a range of about a mile, and when a series of
+them are shot upward in the direction of a hostile plane it is no easy
+matter for the aviator to pass through this "barrage." Once a "flaming
+onion" touches an aeroplane the craft is set on fire, and then, unless a
+miracle happens, the aviator falls to his death.
+
+The German gunners, however, could not use these to advantage while the
+French planes kept so high up, though the shrapnel was a menace, for
+the Hun guns shot far and with excellent aim. A number of the scout
+machines were hit, Tom's receiving three bullets through the wings,
+while Jack's engine was nicked once or twice, though with no serious
+damage.
+
+But as for the German planes they declined the combat that was offered
+them. Probably they had different plans in view. It soon became evident
+to Tom, Jack and the others that to fly at that height meant discovering
+nothing down below. The distance was too great. The big gun might be
+hidden almost anywhere below them, but until it was fired, disclosing
+its presence by an unusual volume of smoke, it would not be discovered.
+Also its fire might be camouflaged by a salvo from a protecting battery.
+
+"It's about time he did that," said Tom to himself at last, as he
+noticed Cerfe, who was the leader of the air squadron, dip his plane in
+a certain way, which was the signal for going down. "We've got to get
+lower if we want to see anything," the young aviator went on. "Though
+they may pot some of us."
+
+Down they went, flying comparatively low but at great speed in order to
+offer less of a target to the gunners below them. And, following
+instructions, each pilot noted carefully the section of the German
+trenches beneath him, and the area back of them. They were seeking the
+big gun.
+
+But, though they looked carefully, it could not be seen, and finally
+when one of the French machines was badly hit, and the pilot wounded, so
+that he had to turn back toward his own lines, Cerfe gave the signal for
+the return.
+
+In all this time not a Hun plane had come out to give battle. What the
+reason for this was could only be guessed at. It may have been that none
+of the German machines was available, or that skillful pilots, capable
+of sustaining a fight with the veterans of the French, were not on hand
+just then. However that may have been, Tom, Jack and the others, after
+firing a few rounds from their machine guns at the trenches, though
+without hope of doing much damage, turned back toward Camp Lincoln.
+
+"Well, then you did not discover anything?" asked Major de Trouville,
+who had been transferred and given the command at Camp Lincoln.
+
+"Nothing," answered Jack.
+
+"If it's in the section we covered, it is well hidden," added Tom.
+
+"And I think, don't you know," went on the Englishman, Haught, "that the
+only way we'll be able to hit on the bally mortar is to fly low and take
+photographs."
+
+"That's my idea," said the major. "If we take a series of photographs
+we can develop them, enlarge them, if necessary, and examine them at our
+leisure. I had thought of this, but it's a slow plan, and it
+means--casualties. But I suppose that can't be avoided. But I wanted to
+try the scouting machines first.
+
+"After all, the taking of photographs from the air of the enemy trenches
+and the land behind them is a most valuable method of getting
+information," he continued.
+
+Men, specially trained for such observation work, examine the
+photographs after the aviators return with the films, and they can tell,
+by signs that an ordinary person would pass over, whether there is a new
+battery camouflaged in the vicinity, whether preparations are under way
+for receiving a large number of troops, or whether a general advance is
+contemplated. Then measures to oppose this can be started. So, Major de
+Trouville was right, photography forms a valuable part of the new
+warfare.
+
+The photographing of the enemy positions is done in big, heavy machines,
+carrying two men. They must fly comparatively low, and have not much
+speed, though they are armed, and it takes considerable of an attack to
+bring them down. But of course the pilot and his observer are in danger,
+and, to protect them as much as possible, scout planes--the single-seat
+Nieuports--are sent out in squadrons to hover about and give battle to
+the German aircraft that come out to drive off the photographers.
+
+"We'll undertake that," proceeded Major de Trouville. "I'll order the
+big machine to get ready for an attempt to-morrow at locating the gun."
+
+"Is it still shooting?" asked Jack.
+
+"Yes, it has just been bombarding Paris; but I have no reports yet as to
+the damage done."
+
+"Aren't we doing anything at all?" asked Tom.
+
+"Oh, yes, our batteries are keeping up a fire on the German lines along
+the front behind which we think the gun is concealed, but what the
+results are yet, we don't know."
+
+"Well, let's hope for clear weather to-morrow," suggested Boughton.
+
+The intervening time was occupied by the aviators in getting everything
+in readiness. The machines were inspected, the automatic guns gone over,
+and nothing left undone that could be thought of to give success.
+
+The next day dawned clear and bright, and, as soon as it was light
+enough to make successful photographs, the big machine set out, while
+hovering above and to either side of it were several Nieuports. Tom and
+Jack were each occupying one of these, ready to give battle to the Huns
+above or below the clouds.
+
+In order to distract the attention of the Germans as much as possible
+from the direct front where the airships were to cross the lines, a
+violent artillery fire was maintained on either flank. To this the
+Germans replied, perhaps thinking an engagement was pending. And so,
+amid the roar of big guns, the flying squadron got off.
+
+"Now we'll see what luck we'll have," mused Tom, as he drove his machine
+forward, being one of the large aerial "V" that had for its angle the
+ponderous photographing bi-motored machine.
+
+Over the German lines they flew, and then the Germans awoke to the
+necessity of ignoring the fire on their flanks and began shooting at the
+airships over their heads.
+
+"This ought to bring out their pilots if they have any sporting blood,"
+thought Jack.
+
+And it did. The French and their allies were no more than well over
+German-occupied territory, before a whole German air fleet swarmed up
+and advanced to give battle. They flew high, intending to get above
+their enemies, and so in the most favorable fighting position. But Tom,
+Jack and the others saw this, and also began to elevate their planes.
+
+"We certainly are going up!" mused Tom, as he noted the needle of his
+height gage showing an altitude of twelve thousand feet. "When are they
+going to stop? We're high above the clouds now."
+
+That was true as regarded himself, Jack, and two other French planes.
+But still the Germans climbed. Doubtless some of them were engaging the
+big machine which was low down, trying to take photographs, but Cerfe
+and Boughton were guarding that.
+
+"Here comes one at me, anyhow!" thought Tom, as he saw a Hun machine
+headed for him.
+
+"Well, the sooner it's over the better. Here goes!" and he pressed the
+release of his automatic gun, meanwhile heading his craft full at the
+German to direct the fire, for that is how the guns are aimed in a
+Nieuport, the gun being stationary.
+
+And so began the battle above the clouds.
+
+
+
+
+CHAPTER XIX
+
+QUEER LIGHTS
+
+
+Tom Raymond's first few shots went wild, as he noted by the tracer
+bullets. Then, steering his machine with his feet, he brought it around
+a trifle, and, having by a quick action risen above his antagonist, he
+let him have a good round, full in the face. The result was disastrous
+to the German, for suddenly the Hun machine burst into flames, the
+gasolene from the punctured tank burning fiercely, and down it went a
+flaming torch of death.
+
+Tom felt some bullets whistle around him, and one exploded as it struck
+part of his engine, but without injuring it.
+
+"Explosive bullets, are they?" mused the young aviator. "Against all the
+rules of civilized warfare. Well, he won't shoot any more," he thought
+grimly.
+
+But though Tom had come victorious from his engagement with his single
+antagonist, he had no sooner straightened out and begun to take stock of
+the situation, than he became aware that he was in great danger. Above
+him, and coming at him with the swiftness of the wind, were two speedy
+German machines, bent cm his destruction.
+
+They were both firing at him, the angles of attack converging, so that
+if one missed him the other would probably get him.
+
+"I've got to get out of this," Tom reasoned. He headed his plane toward
+the antagonist on his right, shooting upward and firing as rapidly as he
+could, and had the satisfaction of seeing the German swerve to one side.
+The fire was too hot for his liking.
+
+The other, however, came on and sent such a burst of fire at Tom that
+the latter realized it was a desperate chance he was taking. He tried to
+get above his enemy, but the other's plane was the speedier of the two,
+and he held the advantage.
+
+Tom's ammunition was running low, and he realized that he must do
+something. He decided to take a leaf out of the book of the Germans.
+
+"I'll go down in a spinning nose dive," he reasoned. "They'll be less
+likely to hit me then. I'll have to go back, I guess, and get some more
+shots. I used more than I thought."
+
+He sent his last drum at the persistent German, and, noting that the
+other was swooping around to attack again, went into the dangerous
+spinning nose dive.
+
+The Germans may have thought they had disabled their antagonist, for
+this dive is one a machine often takes when the pilot has lost control.
+But in this case Tom still retained it, and when he had dropped out of
+the danger zone, he prepared to straighten out and fly back over his own
+lines.
+
+It is not easy to straighten an airplane after such a dive, and for a
+moment Tom was not sure that he could do it. Often the strain of this
+nose dive, when the machine is speeding earthward, impelled not only by
+its propellers, but by the attraction, of gravitation, is so great as to
+tear off the wings or to crumple them. But after one sickening moment,
+when the craft seemed indisposed to obey him, Tom felt it beginning to
+right itself, and then he started to sail toward the French lines.
+
+He was not out of danger yet, though he was far enough away from the two
+German machines. But he was so low that he was within range of the
+German anti-aircraft guns, and straightway they began shooting at him.
+
+To add to his troubles his engine began missing, and he realized that it
+had sustained some damage that might make it stop any moment. And he
+still had several miles to travel!
+
+But he opened up full, and though the missing became more frequent he
+managed to keep the motor going until he was in a position to volplane
+down inside his own lines, where he was received with cheers by his
+comrades of the camp.
+
+"How goes it?" asked Major de Trouville anxiously.
+
+"I think we are holding them off," said Tom.
+
+He was the first one who had had to return, much to his chagrin. He
+leaped out of his craft, and was about to ask for another to go back and
+renew the battle of the clouds, when he saw the big photographing
+machine returning, accompanied by all but two of the escorting craft.
+
+"A pair missing," murmured the major, as he searched the sky with his
+glasses.
+
+And Tom wondered if Jack's machine was among those that had not headed
+back.
+
+Eagerly he procured a pair of binoculars, and when he had them focused
+he identified one machine after another, at last picking out his chum's.
+It did not seem to be damaged.
+
+But two of the French craft had been brought down--one in flames, the
+report had it, and the other out of control, and both fell within the
+German lines.
+
+"Did you get any photographs of the big gun?" asked the major, when the
+men in the double machine had made a landing.
+
+"We got lots of views," answered the photographer, "but what they show
+we can't say. As far as having seen the gun goes, we didn't spot it."
+
+"Well, maybe the photographs will reveal it," suggested the major. "Ah,
+but I am sorry for the two that are lost!"
+
+Jack's experience had been less exciting than Tom's. One machine had
+attacked the former, and there had been a hot engagement for a while,
+but the German had finally withdrawn, though to what extent he was
+wounded or his machine damaged Jack did not know.
+
+However, the picked squadron had reason to feel satisfied with their
+efforts. All now depended on the developing of the photographs, and this
+was quickly done. For this part of warfare is now regarded as so
+important that it is possible for a plane to fly over an enemy's
+station, take photographs and have prints in the hands of the commanding
+officer inside of an hour, if all goes well.
+
+Carefully the photographs were examined by men expert in such matters.
+Eagerly they looked to discover some signs of the emplacement of the big
+gun. But one after another of the experts shook his head.
+
+"Nothing there," was the verdict.
+
+"Then we've got to try again," decided Major de Trouville. "We must
+find that gun and destroy it!"
+
+"Well, we're ready," announced Tom, and the others of the picked
+squadron nodded in assent.
+
+And then began an organized campaign to locate the monster cannon. It
+continued to fire on Paris at intervals. Then three days went by without
+any shells falling, and the rumor became current that the gun had burst.
+If this had happened, there was another, or more, to take its place, for
+again the bombarding of the city began.
+
+Meanwhile the air scouts did their best to find the place of the firing.
+Hundreds of photographs were taken, and brave scouts risked death more
+than once in flying low over suspected territory. But all to no purpose.
+Several were killed, but others took their places. Jack was hit and so
+badly wounded that he was two weeks in the hospital. But when he came
+out he was again ready to join Tom in the search.
+
+No word came as to the whereabouts of Bessie and her mother, nor did Tom
+hear anything of his father. The lack of information was getting on the
+nerves of both boys, but they dared not stop to think about that, for
+the army needed their best efforts as scouts of the air, and they gave
+such service gladly and freely.
+
+Every possible device was tried to find the location of the German gun,
+and numerous battles above the clouds resulted at different times during
+the scout work.
+
+On the whole the advantage in these conflicts lay with the armies of the
+Allies, the Germans being punished severely. Once a German plane was
+brought down within the French lines, and its pilot made a prisoner.
+
+It was hoped that some information might be gotten out of the German
+airman that would lead to the discovery of the big gun, but, naturally,
+he did not reveal the secret; and no more pressure was brought to bear
+on him in this matter than was legitimate. The hiding place of the gun
+remained a secret.
+
+Its possible size and the nature of its shooting was discussed every day
+by Tom, Jack and their comrades. In order to make a cannon shoot a
+distance of about eighty miles it was known that it was necessary to get
+the maximum elevation of forty-five degrees. It was also calculated that
+the shell must describe a trajectory the highest point in the curve of
+which must be thirty-five miles or more above the earth. In other words
+the German cannon had to shoot in a curve thirty-five miles upward to
+have the missile fly to Paris. Of course at that height there was very
+little air resistance, which probably accounted for the ability of the
+missile to go so far. That, and the sub-calibre shell, made the
+seemingly impossible come within the range of possibility.
+
+"What are you going to do, Tom?" asked Jack one evening, after an
+unsuccessful day's flight. For Tom was going toward his hangar.
+
+"Going up."
+
+"What for?" Jack went on.
+
+"Oh, no reason in particular. I just feel like flying. We didn't do much
+to-day. Had to come back on account of mist, and we didn't see enough to
+pay for the petrol used. Want to come along?"
+
+"Oh, I might, yes."
+
+Tom and Jack went up, as did several more. But the two remained up
+longer than did the others, and Jack was somewhat surprised to see his
+chum suddenly head for the German lines, but at an angle that would take
+him over them well to the south of where the observation work had been
+carried on.
+
+"I wonder what he's up to," mused Jack; "Guess I'd better follow and
+see."
+
+There was not much chance of an aerial battle at that hour, for dusk was
+coming on. There had been no bombing squadron sent out, which would
+have accounted for Tom going to meet them, and Jack wondered greatly at
+his chum's action.
+
+Still there was no way of asking questions just then, and Jack followed
+his friend. They sailed over the German lines at a good height, and Jack
+could keep Tom in view by noting the lights on his plane.
+
+These were also seen by the Germans below, and the anti-aircraft guns
+began their concert, but without noticeable effect. None of the Hun
+airmen seemed disposed to accept a challenge to fight, so Tom and Jack
+had the upper air to themselves.
+
+Below them the boys could see flashes of fire as the various guns were
+discharged; and at one point in the lines there was quite an artillery
+duel, the French batteries sending over a shower of high explosive
+shells in answer to the challenge from the Boches.
+
+It was not until Jack had followed his chum back to Camp Lincoln, and
+they had made a landing, that a conversation ensued which was destined
+to have momentous effect.
+
+"Jack, did you notice the peculiar colored lights away to the north of
+where we were flying?" asked Tom, as they divested themselves of their
+fur garments.
+
+"You mean the orange colored flare, that turned to green and then to
+purple?" asked Jack.
+
+"That's it. I thought you'd see it. I wonder what it means?"
+
+"Oh, perhaps some signal for a barrage or an attack. Or they may have
+been signaling another battery to try to pot us."
+
+"No, I hardly think so. They didn't look like signal fires. I must ask
+Major de Trouville about that."
+
+"What?" inquired the major himself, who was passing and who heard what
+Tom said.
+
+"Why, we noticed some peculiar lights as we were flying over the German
+lines in the dark. There was an orange flare, followed by a green light
+that changed to purple," answered Tom.
+
+"There was!" cried the major, seemingly much excited. "You don't mean
+it! That's just what we've been hoping to see! Come, you must tell
+Laigney about this."
+
+
+
+
+CHAPTER XX
+
+THE BIG GUN
+
+
+For a moment Tom and Jack did not quite know what to make of the
+excitement of Major de Trouville. And excited he certainly was beyond a
+doubt.
+
+"You must come and tell this to Lieutenant Laigney at once," he said.
+"It may mean something important. Are you sure of the sequence of the
+colors?" he asked. "That makes all the difference."
+
+"There was first an orange tint," said Tom, "which was followed by green
+and purple, the last gradually dying out."
+
+"Orange, green and purple," murmured the major. "Can it be that for
+which we are seeking?"
+
+He hurried along with the boys, seemingly forgetting, in his haste and
+excitement, that he was their ranking officer. But, as has been noted,
+the aviators are more like friends and equals than officers and men.
+There is discipline, of course, but there is none of the rigidity seen
+in other branches of the army. In fact the very nature of the work
+makes for comradeship.
+
+Tom and Jack knew, slightly, the officer to whom Major de Trouville
+referred. Lieutenant Laigney was an ordnance expert, and the inventor of
+a certain explosive just beginning to be used in the French shells. It
+was simple, but very powerful.
+
+"You must tell him what you observed--the strange colored lights, my
+boys," said the major. "By the way, I hope you carefully noted the time
+of the colored flares."
+
+Tom and Jack had. That was part of their training, to keep a note of
+extraordinary happenings and the time. Often seemingly slight matters
+have an important bearing on the future.
+
+They found Lieutenant Laigney in his quarters, making what seemed to be
+some intricate calculations. He saluted the major and nodded to the
+boys, whom he had met before.
+
+"Lieutenant," began Major de Trouville, "these young gentlemen have
+something to tell you. I want you to think it over in the light of what
+you told me about the action of that new explosive you said the Germans
+might possibly be using."
+
+"Very good, Major. I shall be delighted to be of any service in my
+power," was the answer.
+
+Then Tom and Jack described what they had seen, giving the location of
+the colored lights as nearly as they could, and the exact time they had
+noted them.
+
+"How long would it take a shell to reach Paris, fired at a distance of
+eighty miles from the city?" asked the major.
+
+The lieutenant made some calculations, and announced the result of his
+findings.
+
+"Then," went on the commanding officer, "if a shell was fired from the
+big gun, say at the moment when these two scouts observed the
+tri-colored fire, it should have reached Paris at seven-fifty-three
+o'clock."
+
+"As nearly as can be calculated, not knowing the exact speed of the
+projectile, yes," answered the lieutenant.
+
+Major de Trouville picked up the telephone and asked to be connected
+with the wireless station.
+
+"Have you had any reports of the bombarding of Paris this evening?" he
+asked. "Yes? What time did the first, or any particular shell, arrive?
+Ah, yes, thank you. That is all at present."
+
+He turned to the others, after having listened to the reply and put the
+instrument away.
+
+"One of the shells exploded in a Paris street at seven-fifty-two o'clock
+this evening," he said.
+
+"It beat your calculations by one minute, Lieutenant Laigney."
+
+"Ah! Then this means--" and the younger officer seemed as excited as the
+major had been when Tom and Jack told him what they had seen.
+
+"It means," finished the commanding officer, "that, in all likelihood,
+these young men have discovered the location of the big German cannon."
+
+"Discovered it!" cried Jack. "Why we didn't see anything!"
+
+"Nothing but those queer lights," added Tom.
+
+Major de Trouville smiled at them, and Lieutenant Laigney nodded his
+head in assent.
+
+"Those queer lights, as you call them," said the ordnance expert, "were
+the flashes of a new explosive. What the Germans call it I do not know.
+For want of a better name we call it Barlite, from the name of Professor
+Barcello, one of our experimenters, who discovered it. But a spy stole
+the secret and gave it to Germany. They must have managed to perfect it,
+though we have not used it as yet, owing to the difficulty in
+constructing a gun strong enough to withstand its terrific power."
+
+"And do you mean they're using this explosive in the big German gun?"
+asked Jack, "And that we really saw it being fired?" cried Tom.
+
+"That is my belief," said the lieutenant. "This explosive burns, when
+fired from a gun, first with an orange flame, changing to green and then
+to purple, as the various gases are given off."
+
+"Those are the very colors we saw!" exclaimed Jack.
+
+"Yes," went on Major de Trouville. "And when I heard you mention them,
+and when I recalled that Lieutenant Laigney had spoken of a certain
+explosive that gave off a tri-colored light, I suspected you had hit on
+the German secret."
+
+"And do you believe we actually saw the giant cannon being fired at
+Paris?" asked Tom.
+
+"Without a doubt. The time of the arrival of one of the shells coincides
+almost to the minute with the time that would elapse after the missile
+was sent on its way, and this was when you saw the queer flashes. You
+have discovered the area where the big gun is placed. All that is needed
+now are some exact observations to give us the exact spot."
+
+"And then we can destroy it!" cried the lieutenant. "Then the menace to
+beloved Paris will have passed!"
+
+"And thanks to our brave American friends!" cried the major, shaking
+hands with Tom and Jack. "You will win promotion for this!" he murmured.
+
+"But the big gun isn't found yet," said Jack.
+
+"Why, if you are right, sir," Tom said to the major, "the shells must
+pass right over our camp."
+
+"They probably do. But at so far above--several miles up so as to reach
+the height of thirty-five--that we never know it. We neither see them
+nor hear them. Boys, I believe you have located the big gun! All that
+now remains is to destroy it!"
+
+
+
+
+CHAPTER XXI
+
+DEVASTATING FIRE
+
+
+Modestly enough Tom and Jack took the new honors that came to them. As a
+matter of fact they were in no wise sure that they had discovered the
+location of the German giant cannon. It was all well enough to come in
+and report seeing some strange-colored flares of fire. But Tom and Jack
+felt that they wanted to see a thing with their own eyes before surely
+believing.
+
+Of course, though, the French experts knew about what they were talking,
+and the major and the lieutenant seemed very sure of their ground.
+
+"I only hope we have had the good luck to have spotted the beasts'
+machine," said Tom.
+
+"You will have the honor of proving it to yourselves in the morning,"
+Major de Trouville told them. "You shall accompany the first scouting
+party that goes out. We will send out two photographing machines, and
+enough of a squadron to meet anything the Huns can put forth. Paris
+shall be delivered from the Boche pests!"
+
+"We'll do our best," said Tom, and Jack nodded in agreement.
+
+It did not take long for the news to spread about Camp Lincoln that the
+two young United States aviators had, very probably, discovered by
+accident the big German gun.
+
+And in telling what they had seen Tom and Jack remarked that the
+peculiar tri-colored fire had been in the midst of other flashes of
+flame, and, doubtless, smoke, but that could not be seen on account of
+the darkness.
+
+"The other flashes were probably guns fired to camouflage the flash from
+the giant cannon, or possibly cannons," observed Major de Trouville.
+"But we shall see what to-morrow brings forth."
+
+The hours of the night seemed long, but there was much to do to get
+ready for the next day's operations. More aviators were sent for, and
+the men of the air spent many hours tuning up their motors and seeing to
+their guns, while the big machines, which it was hoped could take
+pictures of the giant cannon's position, were gone over carefully.
+
+In addition some powerful French guns were brought up--some of the
+longest range guns available, and it was hoped that the big aeroplanes
+might signal by wireless the exact location of the super-gun, so that a
+devastating fire could be poured on it, as well as bombs be dropped
+from some machines especially fitted for that work.
+
+Camp Lincoln, where the picked squadron was situated, was in the
+neighborhood of Soissons, France, in a sector held by the French troops.
+The lines of German and French trenches, with No Man's Land in between,
+was about ten miles to the east of this point. This section had changed
+hands twice, once being occupied by the Germans, and then abandoned by
+them when they made the great withdrawal.
+
+Now, perhaps ten miles back of the German trenches, the great gun was
+hidden, making its total distance from Paris about eighty miles, but its
+distance from Camp Lincoln something less than twenty miles.
+
+Modern guns easily shoot that distance, but the commander of the forces
+in this section was going to shorten that. Soissons was the nearest
+large city to the camp. As a matter of fact the air squadron was some
+distance east of that place, and nearer the battleline. So that it was
+comparatively easy, once the location of the big gun was known, to bring
+up heavy artillery behind the French lines to batter away at its
+emplacement.
+
+After a night of arduous labor, during which there was anxiety lest the
+Germans find out what was going on, morning broke, and to the relief of
+all it was bright.
+
+There was an early breakfast, and then the aviators' helpers wheeled the
+machines from the hangars. Several big photographing craft were in
+readiness, and ten bombing planes were in reserve.
+
+Major de Trouville inspected his brave men. They were as eager as dogs
+on the leash to be off and at the throat of the Huns. A wireless message
+from Paris had come in soon after breakfast, stating that nearly a score
+had been killed in the capital the previous night by fire from the
+"Bertha."
+
+"And it's up to us to avenge them!" exclaimed Jack.
+
+"That is what we'll do if we have any luck!" added Tom grimly.
+
+There was a last consultation of the officers, instructions were gone
+over, and everything possible done to insure success. The moment a big
+gun was sighted, the signal was to be given and the French long-range
+cannon would open fire, while the bombing machines would also do their
+part.
+
+"All ready! Go!" called the major, and there was a rattle and a roar
+that drowned his last word. The men of the air were off.
+
+Led by Tom and Jack, the others followed. Up and up they arose, the
+smaller planes flying high as a protection to the more cumbersome
+machines of the bi-motored type. And soon the squadron, the largest that
+had yet ascended from Camp Lincoln, was hovering over the German lines.
+
+The Huns seemed to realize that something more than an ordinary attack
+from the air was impending, for soon after the anti-aircraft guns began
+firing a swarm of German aviators took the air, and there was no
+shirking battle this time. The Huns so evidently felt the desperate need
+of driving away their attackers, that this, more than what the major and
+lieutenant had said, convinced Tom and Jack that they were at last on
+the track of the big gun.
+
+Of course the two boys could not communicate with one another, but they
+said afterward that their thoughts were the same.
+
+The battle of the air opened with a rush and a roar. The Germans, though
+outnumbered by their opponents, did not hesitate, but came on fiercely.
+They attacked first the big photographing planes, for they realized that
+these were the real "eyes" of the squadron. The impressions they
+received, and the views they carried back, might mean the failure of the
+German plans.
+
+But the French were ready for this, and the swift little Nieuports,
+dashing here and there, swooping and rising, attacked the other planes
+vigorously.
+
+It was give and take, hammer and tongs, fire and be fired on, smash and
+be smashed. It was not as one-sided a battle as it would seem it might
+have been owing to the superiority of numbers in favor of the French--at
+least at first. Several of the Allies' planes were sent down, either out
+of control, or in flames. But the Huns paid dearly for their quarry.
+
+Jack and Tom ran serious risks, for the Germans, realizing that the two
+leading planes had some special mission, attacked them fiercely. Tom
+managed to shake off and disable his antagonist. But Jack's man shot
+with such good aim that he pierced his gasolene tank, and had it not
+been that Jack was able to thrust into the hole one of some wooden plugs
+he had brought along for the purpose, he might have had to come down
+within the German lines. But the wood swelled, filled the hole, and then
+the petrol came out so slowly that there was comparatively little
+danger.
+
+And having, with some of their companions, fought their way through the
+German air patrol, and having escaped with minor damage to their guns,
+Jack and Tom looked down at the place where they had seen the queer
+lights.
+
+And then, high up and at a vantage point, while below them hovered their
+photographing planes, the two young aviators beheld a curious sight.
+
+In German-occupied territory, but on French soil, they saw near a
+railroad junction, where they were fairly well hidden in a camouflaged
+position, not one, but three monster Hun cannons. The guns looked more
+like gigantic cranes than like the accepted form of a great rifled piece
+of armament. The guns were so mounted that they could be run out on a
+small track at the moment of firing, and then propelled back again, like
+some of the disappearing cannon at Sandy Hook and other United States
+forts. Only the German guns advanced and retreated horizontally, while
+the usual method is vertically.
+
+"We've discovered 'em! There they are!" cried Tom, but of course he
+could not hear his own voice above the roar of his motor. But he knew
+that he and Jack were over the very spot where the night before they had
+seen the colored flares from the great guns.
+
+And they had, indeed, by a most lucky chance, located the big German
+guns, for there were three of them. They were placed almost midway
+between the railroad station of Crepyen-Lannois and the two forts known
+as "Joy Hills," forts which had fallen into German hands. There were
+two railroad spur lines from the station, and on these the heavy guns
+were moved to position to fire, and then run back again. Other spur
+lines were under course of construction, Jack and Tom, as well as the
+other airmen, could observe, indicating that other guns were to be
+mounted, perhaps to take the place of some that might be destroyed.
+
+As a matter of fact, as was learned later, there were but two guns in
+service at this time, one of the three having burst.[1]
+
+[Footnote 1: While of course this story is fiction, the description
+given above of the great guns and their method of firing and concealment
+is strictly in accord with the facts, and made from a sight of aeroplane
+photographs taken by the French, and from an official report, published
+April 26, 1918, by Deputy Charles Leboucq of the Department of the
+Seine.]
+
+Even as the French squadron came hovering over the place where the
+German monster guns were placed, the advance of Tom, Jack and their
+comrades being disputed by the Huns, one of the super-guns was run out
+to fire on its specially constructed platform.
+
+That this should be done in the very faces of the French was probably
+accounted for by the fact that the Germans were taken by surprise. It
+took some little time to arrange for firing one of the big cannons, and
+it was probably too late, after the French airmen were hovering above
+it, to get word to the crew not to discharge it.
+
+As it happened, Tom and Jack, with Boughton, who had kept pace with
+them, witnessed the firing of the big gun. As it was discharged, ten
+other heavy guns, but, of course, of much less range, were fired off,
+being discharged as one to cover the report of the giant mortar. And at
+the same time dense clouds of smoke were sent up from surrounding hills,
+in an endeavor to screen the big gun from aeroplane observation. But it
+was too late.
+
+In another moment, and even as the echoes of the reports of the ten
+cannons and the big gun were rumbling, the bombing machine of the French
+came up and began to drop explosives on the spot. At the same time word
+of the location of the great cannon was wirelessed back to the camp, and
+there began a devastating fire on the guns that had been, and were even
+then, bombarding Paris.
+
+
+
+
+CHAPTER XXII
+
+OVER THE RHINE
+
+
+It was a battle of the air and on the ground at the same time. From
+above the French, American and British airmen were dropping tons of
+explosives on the emplacements of the big guns and on the railway spurs
+that brought them to the firing points. It might seem an easy matter for
+an airship flying over a place to drop an explosive bomb on it and
+destroy it. But, on the contrary, it is very difficult.
+
+The bombing plane must be constantly on the move, and it takes a pretty
+good eye to calculate the distance from a great height sufficiently well
+to make a direct hit.
+
+But a certain percentage of the bombs find their mark, and they did in
+this case. Tom and Jack, as well as the other scouts, looking down from
+their planes, saw fountains of brown earth being tossed into the air as
+the French bombs exploded. At the same time the photographers in the
+other planes were making pictures of the guns and their location.
+
+They were hindered in this not only by the shooting of the Germans from
+below, who were working their anti-aircraft guns to their capacity, but
+by screens of smoke clouds, which were emitted by a special apparatus to
+hide the big guns. At the same time other cannons were being fired to
+disguise the sound from the immense long-range weapon, but this was of
+little effect, now that the location had been discovered.
+
+Meanwhile a score or more of the Hun planes appeared in the air. They
+had taken flight as soon as their pilots saw the squadron of enemy
+machines approaching, and were eager, this time, to give battle.
+
+"Our work's being cut out for us," murmured Tom, as he steered his
+machine to engage a German who seemed eager for the fray. Tom sent a
+spray of bullets at his enemy, and was fired at in turn. He knew his
+craft had been hit several times, but he did not think it was seriously
+damaged.
+
+Jack, too, as he could tell by a quick glance, was also engaged with a
+German, but Tom had no time then to bestow on mere observation. His
+antagonist was a desperate Hun, bent on the utter destruction of Tom's
+machine. They came to closer quarters.
+
+Down below the fighting was growing more furious. It was in the form of
+an artillery duel. For now the French observation machines were
+wirelessing back the range, and French shells were falling very near the
+big guns.
+
+The heavy guns, in modern warfare, are placed miles away from the
+objects they wish to hit, and the only way to know where the targets are
+is by aeroplane observation. When the guns are ready to fire one of the
+artillery control planes goes up over the enemy's territory. Of course
+it is the object of the enemy to drive it away if possible.
+
+But, hovering in the air, the observer in the double-motored machine
+notes the effect of the first shot from his side's cannon. If it goes
+beyond the mark he so signals by wireless. If it falls short he sends
+another signal. Thus the range is corrected, and finally he sees that
+the big shells are landing just where they are needed to destroy a
+battery, or whatever is the object aimed at. The observation complete,
+the machine goes back over its own lines--if the Germans let it.
+
+This sort of work was going on below them while Tom, Jack and the others
+in the Nieuports were engaging in mortal combat with the Hun fliers.
+Some of the heavy French shells fell beyond the emplacements of the big
+guns, and others were short. The observers quickly made corrections by
+wireless for the gunners. Tom Raymond, after a desperate swoop at his
+antagonist, sent him down in flames, and then, seeking another to
+engage, at the same time wondering how Jack had fared, the young aviator
+looked down and saw one of the largest of the French shells fall
+directly at the side of the foremost of the three German giant cannons.
+
+There was a terrific explosion. Of course, Tom could not hear it because
+of his height and the noise his motor was making, but he could see what
+happened. A great breach was made in the long barrel of the German gun,
+and its emplacement was wrecked, while the men who had been swarming
+about the place like ants seemed to melt into the earth. They were
+blotted out.
+
+"One gone!" exclaimed Tom grimly. And then he noted that the other two
+guns had been withdrawn beneath the camouflage. They were no longer in
+sight, and hitting them was a question of chance.
+
+Still the French batteries kept up their fire, hoping to make another
+hit, but it would be a matter of mere luck now, for the guns were out of
+observation.
+
+The airmen observers, however, still had a general idea of where the
+super-weapons were, and the French gunners continued to send over a rain
+of shells, while the bombing machines, save one that had been destroyed
+by the German fire, kept dropping high explosives in the neighborhood.
+
+"The place will be badly chewed up, at any rate," mused Tom.
+
+He glanced in the direction where he had last seen Jack, and to his
+horror saw his chum's machine start downward in a spinning nose dive.
+
+"I wonder if they've got him, or if he's doing that to fool 'em,"
+thought Tom. As he was temporarily free from attack at that instant he
+started toward his friend. Hovering over him, and spraying bullets at
+Jack, was a German machine, and Tom realized that this fighter might
+have injured, or even killed, Jack.
+
+"Well, I'll settle your hash, anyhow!" grimly muttered the young birdman
+to himself. He sailed straight for the Hun, who had not yet seen him,
+and then Tom opened fire. It was too late for the German to turn to
+engage his second antagonist, and Tom saw the look of hopelessness on
+his face as the bullets crashed into his machine, sending it down a
+wreck.
+
+"So much for poor old Jack!" cried Tom.
+
+They were well over the German lines now, and the fight was going
+against the French. That is, they were being outnumbered by the Hun
+planes, which were numerous in the air. But the French had accomplished
+their desperate mission. One of the German guns was out of commission,
+and perhaps others, while the location had been made "considerably
+unhealthy," as Boughton expressed it afterward.
+
+It was time for the French to retire, and those of their machines that
+were able prepared to do this. But Tom was going to see first what
+happened to Jack before he returned to his lines.
+
+"He may be spinning down, intending to get out of a bad scrape that way,
+and then straighten for a flight toward home," mused Tom. "Or he may
+be--"
+
+But he did not finish the sentence.
+
+There was but one way for Tom to be near Jack when the latter landed--if
+such was to be his fate--and to give him help, provided he was alive.
+And that was for Tom himself to go down in a spinning nose dive, which
+is the speediest method by which a plane can descend. But there is great
+danger that the terrific speed may tear the wings from the machine.
+
+"I'm going to risk it, though," decided Tom.
+
+Down and down he spun, and as he looked; he became aware, to his joy,
+that Jack had his machine under some control.
+
+"He isn't dead yet, by any means," thought Tom. "But he may be hurt. I
+wonder if he can make a good landing? If he does it will be inside the
+German lines, though, and then--"
+
+But Tom never faltered. He must rescue his chum, or attempt to, at all
+hazards.
+
+Down went both machines, Jack's in the lead, and then, to his joy, Tom
+saw his friend bring the machine on a level keel again and prepare to
+make a landing. This was in a rather lonely spot, but already, in the
+distance, as Tom could note from his elevated position, Germans were
+hurrying toward the place, ready to capture the French machine.
+
+"If he's alive I'll save him!" declared Tom. "My machine will carry
+double in a pinch, but he'll have to ride on the engine hood."
+
+Tom was going to take a desperate chance, but one that has been
+duplicated and equalled more than once in the present war. He was going
+to descend as near Jack's wrecked machine as he could, pick up his chum,
+and trust to luck to getting off again before the Germans could arrive.
+
+That Jack was once more master of his craft became evident to his
+friend. For the Nieuport was slowing down and Jack was making ready for
+as good a landing as possible under the circumstances. It was plain,
+however, that his machine was damaged in some way, or he would have gone
+on flying toward his own lines.
+
+Tom saw his chum drop to the ground, and then saw him quickly climb out
+of his seat, loosing the strap that held him in. By this time other
+German planes were swooping toward the place, and a squad of cavalry was
+also galloping toward it.
+
+"I'll beat you, though!" cried Tom fiercely.
+
+He throttled down his engine, intending to give it just enough gas to
+keep it going, for he would have no one to start it for him if the motor
+stalled. He calculated that he could taxi the craft across the ground
+slowly enough for Jack to jump on and then he could get away, saving
+both of them.
+
+Jack understood the plan at once. He waved his hand to Tom to show that
+he would be ready, and Tom felt a joy in his heart as he realized that
+his chum was uninjured.
+
+Down to the ground went Tom, and he guided his machine toward Jack,
+standing beside his own damaged craft, waiting. Suddenly there was a
+sharp report, and Tom saw Jack's machine burst into flames.
+
+"He fired into the gasolene tank!" thought Tom. "That's the boy! He
+isn't going to let the Huns get his machine and the maps and
+instruments. Good!"
+
+Jack leaped back from the blaze that suddenly enveloped his aeroplane
+and then ran toward Tom's machine. As he leaped upon the engine hood,
+which he could do with little more risk than boarding a swiftly moving
+trolley car, there was a burst of rifle fire from the cavalry, some of
+which had reached the scene.
+
+Jack gave a gasping cry, and fell limp. He almost slipped from the motor
+hood, but with one hand Tom quickly fastened his companion's life belt
+to the support and then, knowing Jack could not fall off, opened his
+engine wide.
+
+Across the ground the double-loaded craft careened, while the cavalry
+opened fire.
+
+"If they hit me now, it's all up with both of us!" thought Tom
+desperately.
+
+But though the bullets splattered all around him, and some hit the
+machine, neither he nor Jack was struck again, nor was any vital part of
+the machinery damaged. Poor Jack, though, seemed lifeless, and Tom
+feared he had arrived the fraction of a minute too late.
+
+Then up rose Tom's plane, up and up, the powerful engine doing its best,
+though the machine was carrying double weight. But the Nieuports are
+mechanical wonders, and once the craft was free of the earth it began
+climbing. Fortunately there were no swift German machines near enough to
+give effective chase, though some of the heavier bi-motored craft opened
+fire, as did the cavalry from below, as well as some of the
+anti-aircraft guns.
+
+But Tom, keeping on full speed, soon climbed up out of danger, and then
+swung around for a flight toward his own lines. He could see, ahead of
+him, the fleet of French planes, going back after the raid on the big
+guns. Tom's plane was the rearmost one.
+
+Then he knew that he was safe! But he feared for Jack!
+
+One after another, such as were left of the raiding party landed. Their
+comrades crowded around them, congratulating them with bubbling words of
+joy. Yet there was sorrow for those that did not return.
+
+"Is he dead?" asked Tom, as orderlies quickly unstrapped Jack, and
+prepared to carry him to the hospital. "Is he dead?"
+
+"Alive, but badly wounded," said a surgeon, who made a hasty
+examination.
+
+And then all seemed to become dark to Tom Raymond.
+
+"Well, Jack, old man, how do you feel?"
+
+"Oh, pretty good! How's yourself?"
+
+"Better, now that they've let me in to see you."
+
+"You got the big guns, I understand."
+
+"You mean _you_ did, too. It was as much your doings as mine. Yes, we
+sprayed 'em good and proper. They won't fire on Paris again right away,
+but I suppose they'll not give up the trick, once they have learned it.
+But we have their number all right. Now you want to hurry up and get
+well."
+
+Jack was in the hospital recovering from several bullet wounds. They had
+not been as dangerous as at first feared, but they were bad enough. Tom
+had come to see him and give some of the details of the great raid,
+which Jack had been unable to hear because of weakness. Now he was
+convalescing.
+
+"What's the idea of hurry?" asked Jack. "Are we going after more big
+cannon?"
+
+"No, this is a different stunt now. We're going over the Rhine."
+
+"Over the Rhine?" and Jack sat up in bed.
+
+"Monsieur--I must beg--please do not excite him!" exclaimed a pretty
+nurse, hurrying up. "The doctor said he must keep quiet."
+
+"But I want to hear about this," insisted Jack. "Over the Rhine! Say,
+that'll be great! Carrying the war into the enemy's country for fair!"
+
+"I'll tell you a little later," promised Tom, moving away in obedience
+to an entreaty from the nurse.
+
+
+
+
+CHAPTER XXIII
+
+OFF FOR GERMANY
+
+
+Whether it was Tom's news or Jack's natural health was not made clear,
+but something certainly caused Jack Parmly to recover strength much more
+rapidly then the surgeons had believed possible, so that he was able to
+leave the hospital soon after Tom's visit.
+
+"And now I want you to explain what you meant by saying we were to go
+over the Rhine," Jack insisted to his chum. "I've been wondering and
+thinking about it ever since you mentioned it, but none of them would
+tell me a thing."
+
+"No, I reckon not," chuckled Tom.
+
+"Why, you old sphinx?"
+
+"Because they didn't know. It's a secret."
+
+"Can you tell me?"
+
+"Sure! Because you're going to be in it if you are strong enough."
+
+"Strong enough? Of course I'll be! Why, I'm feeling better every minute!
+Now you go ahead and relieve my anxiety. But first tell me--have you had
+any news of your father?"
+
+Tom shook his head.
+
+"Not a word," he answered. "I'm beginning to feel that he has been
+captured by the Germans."
+
+"That's bad," murmured Jack. "And now, have you heard anything about--"
+
+"Bessie and her mother?" finished Tom, breaking in on his chum's
+question with a laugh. "Yes, I'm glad I can give you good news there.
+They are all right, and I have a letter from Bessie for you. She wants
+you to come and see her."
+
+"You have a letter? Why didn't you give it to me before? You fish!"
+
+"It just came. And so did news about their safety."
+
+"Then the spy didn't get 'em after all."
+
+"Oh, yes, he got 'em all right! But he bungled the job, or rather,
+Bessie bungled it for him. They were rescued, and the spy was locked up.
+We're to go to Paris to see them. They'll tell us all about it then."
+
+"But what has that to do with our going over the Rhine?"
+
+"Nothing. We're to go to Paris for a rest, and to get in shape for a big
+effort against the Germans. I'll tell you about it."
+
+"Forge ahead, then."
+
+Tom got up to look at the doors and windows of the French cottage back
+of the lines, where Jack had been moved to complete his recovery. Tom
+and Jack, after the sensational raid, had been given leave of absence.
+
+"I just want to make sure no one hears what I say, for it's a dead
+secret yet," Tom went on. "But this is the plan. The French have several
+of the biggest and newest Italian planes--planes that can carry half a
+dozen men and lots of ammunition. Our aerodrome is going to be shifted
+to the Alsace-Lorraine front, and from there, where the distance to
+German territory is shorter than from here, we are to go over the Rhine
+and bombard some of their ammunition and arms factories, and also
+railroad centers, if we can reach 'em."
+
+"Good!" cried Jack. "I'm with you from the fall of the hat!"
+
+"First you've got to build up a little," stated Tom. "There is no great
+rush about this Rhine-crossing expedition. A lot of plans have to be
+perfected, and we've got to try out the Italian plane. And, before that,
+we are to go to Paris."
+
+"Who says so?"
+
+"Major de Trouville. He's greatly pleased with the result of the raid on
+the big German guns, and says we're entitled to a vacation. Also he
+knows I want to make some more inquiries about my father. But I fear
+they will be useless," and Tom sighed.
+
+"And are we to go to see Mrs. Gleason?" asked Jack.
+
+"Yes. And Bessie, too. They'll tell us all that happened."
+
+A few days later, having received the necessary papers, Tom and Jack
+were once more on their way to the capital. And this time they did not,
+with others, have to suffer the danger and annoyance of the long-range
+bombardment. It was over for a time, but there was no guarantee that the
+Germans would not renew it as soon as they could repair the damage done
+to their giant cannons.
+
+The boys found Bessie and her mother in lodgings in a quiet part of
+Paris, and were met with warm greetings. Then the Gleasons told their
+story.
+
+They had been inveigled out of their lodgings by the false note from the
+boys, and had immediately been taken in charge by the spy, who, it was
+proved, was an agent of the infamous Potzfeldt. But Bessie, after
+several days' captivity in an obscure part of the great city, managed to
+drop a letter out of the window, asking for help.
+
+The police were communicated with, and not only rescued Mrs. Gleason and
+her daughter, but caught the spy as well, and secured with him papers
+which enabled a number of Germany's ruthless secret service agents to be
+arrested.
+
+It was because of the necessity for keeping this part of the work quiet
+that no word of the rescue of Bessie and her mother was sent to the boys
+until after the big gun raid.
+
+There was much to be talked about when the friends met once more, and
+Mrs. Gleason said she and Bessie were going back to the United States as
+soon as they could, to get beyond the power of Potzfeldt.
+
+As Tom had feared, there was no news of his father, but he did not yet
+give up all hope.
+
+"If he's a prisoner there's a chance to rescue him," he said.
+
+The time spent in Paris seemed all too short, and it came to an end
+sooner than the boys wished. Jack was almost himself again, though he
+limped slightly from one of the German bullets in his leg. There was
+every hope, however, that this would pass away in time.
+
+Good-byes were said to Bessie and her mother, and once more the two Air
+Service boys reported to their aerodrome. There they found not one, but
+two, of the big Italian machines, which are capable of long flight,
+carrying loads that even the most ponderous bombing plane would be
+unable to rise with.
+
+Preparations for the bold dash into the enemy's country went on
+steadily and swiftly. Tom and Jack were trained in the management of the
+big birds of the air, and though it was essentially different from what
+they had been used to in the Nieuports and the Caudrons, they soon
+mastered the knack of it, and became among the most expert.
+
+"I believe I made no mistake when I picked them to be part of the
+raiding force," said Major de Trouville.
+
+"Indeed you did not," agreed Lieutenant Laigney. "Their work in
+discovering the big guns, and their help in silencing them, showed what
+sort of boys they are."
+
+And finally the day came when those who were to take part in the raid
+across the Rhine were to proceed to a point within the French lines from
+which the start was to be made.
+
+Other Italian planes would await them there, and there they would
+receive final instructions.
+
+They bade farewell to their comrades in Camp Lincoln, and were given
+final hand-shakes, while more than one, struggling to repress his
+emotion wished them "_bonne chance_!"
+
+This raid against one of the largest and most important of the German
+factory and railroad sections had long been contemplated and details
+elaborately worked out for it. The start was to be made from the nearest
+point in French-occupied territory, and it was calculated that the big
+Italian machines could start early in the evening, cross the Rhine,
+reach their objective by midnight, drop the tons of bombs and be back
+within the French lines by morning.
+
+Such, at least, was the hope. Whether it would be realized was a matter
+of anxious conjecture.
+
+At last all was in readiness. The final examinations of the machines and
+their motors had been made and the supplies and bombs were in place.
+
+"Attention!" called the commander. "Are you ready?"
+
+"Ready!" came from Tom, who was in command of one machine.
+
+"Ready!" answered Haught, who was in charge of the second.
+
+"Then go, and may good fortune go with you!"
+
+There was a roar of the motors, and the big, ponderous machines started
+for Germany.
+
+Would they ever reach it?
+
+
+
+
+CHAPTER XXIV
+
+PRISONERS
+
+
+Under the evening stars, the two big Italian machines slowly, and, it
+must be said, somewhat ponderously, as compared with a speedy Nieuport,
+winged their way toward the German river, behind which it was hoped,
+some day, to drive the savage Huns.
+
+"What do you think?" asked Jack of his chum, for in these latest
+machines, by reason of the motors being farther from the passengers, and
+by means of tubes, some talk could be carried on.
+
+"I don't know just what to think," was the answer. "So much has happened
+of late, that it's almost beyond my thinking capacity."
+
+"That's right. And yet I can guess one thing you have in mind, Tom, old
+scout."
+
+"What is it?"
+
+"Your father! You're hoping you can rescue him."
+
+"That's right, I am. And as soon as this drive is over--if we come back
+from it with any measure of success, and I can get a long leave of
+absence--I'm going to make a thorough search for him."
+
+"And I'll be with you; don't forget that!"
+
+There was not time for too much talk of a personal nature, as Tom and
+Jack had to give their attention to the great plane. The motors were
+working to perfection, and with luck they should, within a few hours, be
+over the great German works, which they hoped to blow up.
+
+Tom was in charge of the plane, but he had Jack and others to help him,
+and there was a certain freedom of movement permitted, not possible in
+even the big photographing or bombing planes.
+
+Down below little could be seen, for they were now over the French and
+German trenches, and neither side was showing lights for fear of
+attracting the fire of the other.
+
+But Tom and Jack had been coached in the course they were to take and,
+in addition, they had a pilot who, a few weeks before, had made a
+partially successful raid in the region beyond the Rhine, barely
+escaping with his life.
+
+And so they flew on under the silent stars, that looked like the small
+navigating lights on other aeroplanes. But, as far as the raiders knew,
+they were the only ones aloft in that particular region just then. They
+had risen to a good height to avoid possible danger from the German
+anti-aircraft guns. There was not much danger from the German planes,
+as, of late, the Huns had shown no very strong liking for night work,
+except in necessary defense.
+
+Off to the left Tom and Jack could see the other big Italian plane, in
+charge of Haught. It carried only small navigating lights, carefully
+screened so as to be invisible from below.
+
+"I suppose you understand the orders," said Tom, speaking to Jack.
+
+"Well, we went over them; but it wouldn't do any harm to refresh my
+memory. You're to be in general charge of the navigation of the plane,
+and I'm to see to dropping the bombs--is that it?"
+
+"That's it. You'll have to use your best judgment when it comes to your
+share. I'll get you over the German works and railroad centers, as
+nearly as I can in the dark, and then it will be up to you."
+
+"I hope I don't fail," said Jack, speaking through the tube.
+
+"You won't. Don't get nervous. Any kind of a hit will throw a scare into
+the Huns, and make them feel that they aren't the only ones who can make
+air raids. But in this case we're not bombing a defenseless town, and
+killing women and children. This is a fortified place we're going over,
+and it's well defended."
+
+"Some difference," agreed Jack.
+
+"And if we can get some direct hits," went on Tom, "and blow to
+smithereens some of their munition or armament factories, we'll be so
+much nearer to winning the war."
+
+And that, in brief, was the object of the flight over the Rhine.
+
+Once more the boys fell silent.
+
+On and on swept the planes. Whether the Germans beneath were aware of
+the danger that menaced them, it is impossible to say. But they made no
+attempt to fire on the Italian craft. Probably because of the darkness,
+and owing to the great height at which they flew, the Huns were in
+ignorance of what was taking place.
+
+On and on in the night and beneath the silent stars they flew. Now Tom
+and the pilot began watching for some landmark--some cluster of lights
+which would tell them their objective was within sight. But for another
+hour nothing was done save to guide the big craft steadily onward.
+
+Once, as Jack looked down, he saw what seemed to be a city, and he
+thought this might be the place where the great factories were situated.
+
+"No, it's an important town," Tom said, in answer to his chum's
+inquiries, "but it is only a town--not a fortress, as the Huns call
+London. That isn't fair game for us."
+
+But half an hour later the pilot spoke sharply, and gave an order. He
+pointed downward and ahead and there a faint glow, and one that spread
+over a considerable area, could be made out.
+
+"That is where we are to drop the bombs," said Tom to Jack.
+
+The other machine, which had flown somewhat behind the one in which were
+the two chums, now swerved over at greater speed. Her pilot, too, had
+picked up the objective.
+
+And now began the most dangerous part of the mission. For it would not
+do to drop the bombs from too great a height. There was too much risk of
+missing the mark. The planes must descend, and then they would be within
+range of the defensive guns.
+
+But it had to be done, and the order was given. As Jack and Tom went
+lower, in company with the other plane, they observed that they were
+over a great extent of factory buildings, where German war work was
+going on.
+
+And now the noise of their motors was heard. Searchlights flashed out
+below them, and stray beams picked them up. Then the anti-aircraft guns
+began to bark.
+
+"We're in for a hot time!" cried Jack.
+
+"You said it!" echoed Tom, as he steered the great plane to get into an
+advantageous position.
+
+Through a glare of light, and amid a hail of shots, the great airships
+rushed down to hover over the German factories. They would not let go
+their bombs until in a position to do the most damage, and this took a
+little time.
+
+"How about it, Tom?" asked Jack, for he was anxious to begin dropping
+the bombs.
+
+"Just another minute. We'll go down a little lower, and so do all the
+more damage."
+
+And down the airship went. She was hit several times, for shrapnel was
+bursting all around, but no material damage was done, though one of the
+observers was wounded.
+
+"Now!" suddenly signaled Tom.
+
+"There they go!" shouted Jack, and he released bomb after bomb from the
+retaining devices.
+
+Down they dropped, to explode on striking, and the loud detonations
+could be heard even above the roar of the motors. Tom noted that the
+other machine was also doing great destruction, and he saw that their
+object had been accomplished.
+
+Several fires broke out below them in different parts of the factory
+property, and soon the Germans had to give so much attention to saving
+what they could, that their fire against the hostile airships noticeably
+slackened.
+
+"Any more bombs left, Jack?" asked Tom.
+
+"A few," answered his chum.
+
+"Let 'em have it now. We're right over a big building that seems to be
+untouched."
+
+Down went the bombs, and such an explosion resulted that it could mean
+but one thing. They had set off a munition factory. This, as the boys
+afterward learned, was the case.
+
+So great was the blast that the great plane skidded to one side, and a
+moment later there came a cry of alarm from some of the crew.
+
+"What's the matter?" shouted Tom.
+
+"Out of control," was the answer. "One of the motors has stopped, and
+we've got to go down."
+
+"Can't we go up?"
+
+"No!" was the despairing answer. "We've got to land within the German
+lines."
+
+And down the great Italian plane went, while her sister ship of the air
+sailed safely off, for it would have been foolhardy for her to have
+tried to come to the rescue.
+
+The crew worked desperately to send their craft up again, but it was
+useless. Lower and lower she went, fortunately not being fired at, so
+great was the confusion caused by the destruction of the factories.
+
+"Take her down as far away as possible from this scene," said Tom to one
+of his men. "If we land in a lonely place we may be able to make repairs
+and get up again."
+
+"I will," was the answer.
+
+Through the light from the burning buildings, a spot in a level field
+was selected for a landing. And down the Italian plane went.
+
+A hasty examination showed little wrong with the motor, and this little
+was quickly repaired.
+
+But the hope of getting the airship to rise again was frustrated, for
+just as the raiding party was about to take its place in the machine
+again, a company of German soldiers came running over the fields,
+demanding the surrender of the intrepid men of the air. There was
+nothing else to do--no time to set the craft on fire.
+
+So it fell into the hands of the Germans! Tom, Jack and the others were
+prisoners!
+
+
+
+
+CHAPTER XXV
+
+THE ESCAPE
+
+
+"Well, this is tough luck!"
+
+"Tough is no name for it, Jack. It's the worst ever! I don't suppose
+they'll do a thing to us after what we did to the factories."
+
+"No. We certainly scotched 'em good and proper. Everything went off like
+a tea party, except our coming down. And we could have gotten up again,
+only those Germans didn't give us a chance."
+
+"You can't blame 'em for that."
+
+"No, I suppose not. But it's hard lines. I wonder why they're keeping us
+here?"
+
+Tom and Jack were talking thus while held prisoners by the Germans,
+after the airship raid over the Rhine. It was an hour after they had
+been forced to descend.
+
+So sudden had been the rush of the German infantry that no chance was
+had to destroy the great Italian plane, and it, and all the crew,
+including the two Air Service boys, had been overpowered, and disarmed.
+They were thrust into what might pass for a guardhouse, and then, a
+guard having been posted, the other soldiers hurried back to aid in
+fighting the fire which had been started in the great factories, and
+which was rapidly spreading to all the German depot.
+
+"Well, it's worth being captured to think of the damage we've inflicted
+on the Huns this night," observed Jack, as he stood with Tom in the
+midst of their fellow prisoners.
+
+"That's right. We don't need to be ashamed of our work, especially as
+we've helped put the big guns out of business. I reckon the Boches won't
+treat us any too well, when they know what we've done."
+
+"And the other plane got away, they tell me," observed one of the French
+crew.
+
+"Yes, I saw her rise and light out for home, after dropping a ton or so
+of bombs on this district," said Tom. "Well, she can go back and report
+a success."
+
+"And let the folks know we're prisoners," said Jack. "It's tough luck,
+but it had to be, I suppose! We're lucky to be alive."
+
+"You said it," agreed Tom. "We came through a fierce fire, and it's a
+wonder that we weren't all shot to pieces. As it is, the plane is as
+good as ever."
+
+"Yes, and if we could only get out to it, and start it going we could
+escape," observed one of the Frenchmen bitterly. "There she is now, on
+as good a starting field as one could wish!"
+
+From their stockade of barbed wire they could look out and see, by the
+glare of the flames, that the great plane stood practically undamaged. A
+good landing had been made, but, unfortunately, in the midst of the
+German ammunition depot section.
+
+"Whew, that was a fierce one!" exclaimed Jack, as a loud explosion
+fairly shook the place where they were held prisoners. "Some ammunition
+went up that time."
+
+Indeed the explosion did seem to be a disastrous one, for there was
+considerable shouting and the delivering of orders in German following
+the blast. Many of the soldiers who had been summoned to stand on guard
+about the barbed-wire stockade, where the captured raiders were held,
+were summoned away, leaving only a small number on duty.
+
+But as these were well armed, and as the wire stockade was a strong one,
+and as Jack, Tom and the others had nothing with which to make a fight,
+they were as safely held as though guarded by a regiment.
+
+"There goes another!" cried Jack, as a second detonation, almost as loud
+as the first, shook the ground. "Some of our bombs must have been time
+ones."
+
+"No," said Tom. "What's probably happening is that the fire is reaching
+stores of ammunition, one after the other. This whole place may go up in
+a minute."
+
+That seemed to be the fear on the part of the Germans, for more orders
+were shouted, and all but two of the soldiers guarding the captives were
+summoned away from the wire stockade.
+
+There had been a bright flare of fire after the second explosion, but
+this soon died away, and the shouts and commands of the officers
+directing the fire-fighting force could be heard.
+
+Tom and Jack were standing near the wire barrier trying to look out to
+see what was going on beyond a group of ruined factory buildings, and at
+the same time casting longing eyes at the great aeroplane which seemed
+only waiting for them, when the two boys became aware of a figure which
+appeared to be slinking along the side of the stockade. This figure
+acted as though it desired to attract no attention, for it kept as much
+as possible in the shadows.
+
+"Did you see that?" asked Jack of his churn in a low voice.
+
+"Yes. What do you make it out to be?"
+
+"He isn't a German soldier, for he isn't in uniform. Have any of our
+crowd found a way out of this place by any chance?"
+
+"I don't know. If they have--"
+
+The boy's words were broken off by a low-voiced call from the slinking
+figure. It asked:
+
+"Are you American, French or English prisoners?"
+
+"Some of each variety," answered Jack, while at the sound of that voice
+Tom Raymond felt a thrill of hope.
+
+"If you get out, is there a chance for you to get away in your
+aircraft?" the figure in the shadow questioned. "Be careful, don't let
+the guards hear."
+
+"There are only two, and they're over at the front gate," said Jack, as
+Tom drew nearer in order better to hear the tones of that voice. "They
+seem more occupied in watching the fire than in looking at us," went on
+Jack.
+
+"Good!" exclaimed the man. "Now listen. I am an American, and I was
+captured by the Germans, through spy work, some time ago, in Paris. I
+was brought here, and they have been trying to force me to disclose the
+secret of some of my inventions.
+
+"I refused, and was sentenced to be shot to-morrow. But to-night you
+fortunately raided this place. My prison was one of the places to be
+blown up, and I managed to escape, without being hurt much. I heard that
+they had captured the crew of one of the airships, and I came to see if
+I could help. They don't know yet that I'm free, and I have two hand
+grenades.
+
+"Now listen carefully. I'll throw the grenades at the front gate. By
+shattering that it may be possible for you to get out. The two sentries,
+will have to take the chances of war. If you get out can you get away in
+your airship?"
+
+"Yes, and we can take you with us--Dad!" exclaimed Tom in a tense
+whisper.
+
+"Who speaks?" hoarsely asked the man in the shadow of the stockade.
+
+"It is I--your son--Tom Raymond! Oh, thank heaven I have found you at
+last!" exclaimed Tom, and he tried to stretch his hand through the
+barbed wire, but it was too close.
+
+"Is it really you, Tom, my boy?" asked Mr. Raymond in a broken voice,
+full of wonder.
+
+"Yes! And to think I should find you here, of all places!" whispered
+Tom. "I won't stop now to ask how it happened. Can you throw those
+grenades at the gate?"
+
+"I can, and will! Tell your friends to run back to the far end of the
+stockade to avoid being hurt. I can crouch down behind some of the
+ruined walls."
+
+Tom and Jack quickly communicated the good news to their friends, that a
+rescue was about to be attempted. It was a desperate chance, but they
+were in the mood for such.
+
+The two guards alone remaining of the force that had been posted about
+the stockade were so distracted by the fires and explosions around them,
+and so fearful of their own safety, that they did not pay much attention
+to the prisoners. So when Tom and Jack passed the word, and the airship
+crew ran to the end of the stockade and crouched down to avoid injury
+when the hand grenades should be exploded, the guards paid little
+attention.
+
+Mr. Raymond, for it was indeed he, crawled to a position of vantage, and
+then threw the hand grenades. They were fitted with short-time fuses,
+and almost as soon as they fell near the stockade gate they exploded
+with a loud report. A great hole was torn in the ground, and one of the
+sentries was killed while the other was so badly injured as to be
+incapable of giving an alarm. The gate was blown to pieces.
+
+"Come on!" cried Tom to his friends, as he saw what his father had done.
+"It's now or never, before they rush in on us."
+
+They raced to the breach in the wire wall of the stockade. Mr. Raymond,
+springing up from where he had taken refuge behind a pile of refuse, was
+there to greet those he had saved, and he and Tom clasped hands silently
+in the gloom that was lighted up by the fires and the bursts of light
+from the munition explosions.
+
+"Oh, Dad! And it's really you!" murmured Tom.
+
+"Yes, my boy! _I_ never expected to see you again. Did you know I was
+here?"
+
+"I never dreamed of it! But don't let's stop to talk. We must get to the
+airship at once! But you are wounded, Dad!"
+
+"Nothing but a splinter from a bomb. It's only a cut on the head, Son,"
+and Mr. Raymond wiped away the blood that trickled down on his face.
+
+The newly freed prisoners lost no time. With a rush they made for the
+airship. If they could only get aboard and start it off all would yet be
+well. Could they do it?
+
+Momentary silence had followed the detonation of the two hand grenades
+thrown by Mr. Raymond, but now there came yells of rage from the
+Germans, disclosing that they had become aware of what was going on.
+
+"Lively, everybody!" cried Tom, as he led the way to the big plane.
+
+"Are we all here?" asked Jack.
+
+A rapid count showed that not one of the brave force had been left
+behind.
+
+"Is there room for me?" asked Mr. Raymond.
+
+"Well, I should say so!"
+
+"If there isn't I'll stay behind," cried Jack.
+
+"No you won't!" exclaimed Tom. "There'll be room all right!"
+
+The running men reached the plane just as they could see, in the light
+of the burning factories, a squad of Germans rushing to intercept them.
+In haste they scrambled aboard, and pressed the self-starter on the
+engine. There was a throbbing roar, answered by a burst of fire from the
+German rifles, for the place had been so devastated that no machine guns
+were available just then.
+
+"All aboard?" asked Tom, as he stood ready to put the motors at full
+speed and send the craft along the ground, and then up into the air.
+
+"All aboard--we're all here!" answered Jack, who had kept count. And Mr.
+Raymond was included.
+
+Then with a louder roar the motors jumped to greater speed, and the
+Italian plane started off. In another instant it rose into the air.
+
+With yells of rage the Germans even tried to hold it back with their
+hands, and, failing, they increased their fire. But though the plane was
+hit several times, and two on board shot, one later dying from his
+wounds, the whole party got off. A few minutes later they were above the
+burning factories, and had a view of the great destruction wrought on
+the German base. So completely destroyed was it that few defense guns
+were left in condition to fire at the aeroplane.
+
+"Well, we did that in great shape!" exclaimed Jack, as they were on
+their way over the Rhine again.
+
+"Couldn't have been better," conceded Tom. "And, best of all, we have
+dad with us."
+
+"How did it all happen?" asked Jack.
+
+"I don't know. We'll hear the story when we are safe in France."
+
+And safe they were as the gray morning broke. They arrived just as the
+crew of the other plane were relating, with sorrow, the fall of Tom,
+Jack and their comrades, and the rejoicing was great when it was known
+they were safe, and had not only outwitted the Huns, but had brought
+away a most important prisoner.
+
+"And now let's hear how it all happened," begged Major de Trouville,
+when the injured had been made as comfortable as possible. There were
+three of these, and one dead on the plane that returned first.
+
+The story of the attack on the German base was given in detail, and then
+Mr. Raymond took up the tale from the point where he had landed in
+Europe.
+
+He had started for Paris, just as he had written Tom, and had taken
+lodgings in the Rue Lafayette. He went out just before the starting of
+the bombardment by the big gun, and so escaped injury, but he fell into
+the hands of some German spies, who were on his trail, and who
+succeeded, after having drugged him, in getting him into Germany.
+
+The spies had succeeded in getting on the trail of a new invention Mr.
+Raymond had perfected, and which he had offered to the Allies. He had
+come to Paris on this business. The Huns demanded that he devote it to
+their interests, but he refused, and he had been held a prisoner over
+the Rhine, every sort of pressure being brought to bear on him to make
+him accede to the wishes of his captors.
+
+"But I refused," he said, "and they decided I should be shot. Whether
+this was bluff or not I don't know. But they never got a chance at me.
+In the night I heard, in my prison, the sound of explosions, and I soon
+realized what had happened. It was your bold airship raid, and one of
+the bombs burst my prison. I ran out and saw the Italian planes in the
+air.
+
+"What then happened you know better than I, but what you probably do not
+know is that you very likely owe your lives to a dispute that arose
+between the German infantry and the air squadron division," and he
+indicated Tom, Jack and the others who had been in the stockade.
+
+"How was that?" asked Jack.
+
+"The airmen claimed you as their prey, and the infantrymen said they
+were entitled to call you theirs. So, even in the midst of the fire and
+destruction, the commandant had to order you put in the stockade until
+he could decide whose prisoners you were. The infantrymen said they had
+captured you, but the airmen said their fire had brought down your
+plane."
+
+"Well, that was partly true," said Tom. "But it was an explosion from
+below that knocked us out temporarily. But we're all right now. And so
+are you, aren't you, Dad?"
+
+"Yes, but I worried a lot, not knowing what had happened to you, Tom,
+and being unable to guess what would happen to me. I was in the hands of
+clever and unscrupulous enemies. How clever they were you can judge when
+I tell you they took me right out of Paris. Perhaps the bombardment made
+it easier. But tell me--what of the big guns?"
+
+"Some of them are out of commission, thanks to your brave boy and his
+comrades," said Major de Trouville.
+
+"Good!" cried Mr. Raymond. "Some rumor to that effect sifted in to me
+there, but it seemed too good to be true. The Germans must be wild with
+rage."
+
+"I guess they are," admitted Jack.
+
+"And it would have gone hard with you if they had found you were the
+ones responsible," went on Tom's father. "As soon as I was out of my
+prison and saw the state of affairs, I managed to get the grenades, and
+I decided to rescue the airship men if I could. I never dreamed my own
+son would be among them, or that I might be brought away."
+
+And now it but remains to add that because of their exploits Tom and
+Jack received new honors at the hands of the grateful French, and,
+moreover, were promoted.
+
+Mr. Raymond, who had steadfastly refused to reveal the secret of his
+invention to the Huns, immediately turned it over to the Allies.
+
+Word of Mr. Raymond's safety and of the success of Tom and Jack was sent
+to those in Bridgeton, and that city had new reasons for being proud of
+her sons.
+
+But the war was not over, and the Germans might be expected to develop
+other forms of frightfulness besides the long-range guns, which, for the
+time being, were silenced. However, the destruction of the factories and
+ammunition stores by the raid over the Rhine was a blow that told
+heavily on the Hun.
+
+"Well, it seems there's another vacation coming to us," said Tom to Jack
+one morning, as they walked away from the breakfast table in their
+mess.
+
+"Yes? Well, I think we can use it. What do you say to a run into Paris
+to see your father? He's surely there now, and I'd like to have a talk
+with him."
+
+"With--_him?_" asked Tom, and there was a peculiar smile on his face.
+
+"Of course," said Jack.
+
+"Oh," was all Tom answered, but he laughed heartily.
+
+And so, with Tom and Jack on their way to Paris, for a brief respite
+from the war, we will take leave of them for a time. That they were
+destined to take a further part in the great struggle need not be
+doubted, for the Air Service boys were not the ones to quit until the
+world had been made a decent place in which to live.
+
+THE END
+
+
+
+
+
+End of the Project Gutenberg EBook of Air Service Boys Over The Rhine, by
+Charles Amory Beach
+
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