The vocal efforts of this new favorite had called forth round after round of applause, for good music never went amiss in Teuton territory.
Among the vigorous hand-clappers the boys noted a well-groomed man, apparently about forty, wearing an affable manner and the best clothes that the continent can produce.
Henri nudged Billy. "Size up Roque, won't you, please, and isn't he a dandy?"
Billy was first inclined to doubt the identity of their taskmaster, who a couple of hours ago was a far cry from being in the glass of fashion. Never before had the boys seen him in that sort of rig.
"You're dead right, Henri, it is the old scout. He's a corker, sure!"
This note of admiration had scarcely sounded when Roque was joined by a slender, wiry individual, also set up as a swell, with a shock of sandy hair, and sporting a monocle.
The fellow with the quizzing glass had apparently moved to get a better view of the singer, as well as to get in touch with the secret agent.
"Wonder if that's the man who spotted Anglin on the parade ground at Hamburg?"
"Don't let your imagination run away with you, Henri," advised Billy, who in speaking was careful not to indicate that his attitude was anything but careless.
The sandy-haired man was taking the same precaution, but Henri, nursing the idea that would not down, was more and more impressed with the belief that the elegant figure was seeking the measure and not the music of the warbler at the other end of the room.
If the singer had sized up the situation, it had not affected his rendering a bit of light opera that was just then exciting an encore. There was nothing at all the matter with his German or with his voice.
Nobody apparently was more delighted than Roque, and he appeared to be expressing his opinion to the wiry listener beside him.
The latter bowed politely and then sauntered toward the revolving door leading into the lounging section of the hotel, fingering a cigar as he proceeded.
Henri edged around nearer to the piano, the player of which was completing the program with a national air, the melody of many voices aiding the performance.
Billy had hardly realized the desertion of his chum when he saw that Roque had changed his position, and was standing nearest the door leading to the street. The secret agent shifted something from his hip to the sidepocket of his coat, and Billy caught the glitter of that something in the swift movement. The boy guessed then that there was trouble brewing.
In the meantime, Henri, in an innocent sort of way, pushed still closer to the pianist, who was hitting the high notes in fine style.
As he passed within a foot of the singer, now idly posing, with an elbow on the piano top, he, without turning his head, joined in the triumphant chorus, but changed two words at the climax, and "beat it" reached Anglin's ear.
The French sleuth never moved a muscle, and it was as if the warning had been passed to a man stone deaf.
Anyone posted, however, would have known that within an arm's length of Anglin was a wall switch which controlled the electric lights by which the room was so brilliantly illuminated.
Billy had just had the experience of being rather rudely thrust aside by a couple of burly troopers, who seemed inspired to get as quickly as possible into the very center of the select circle.
"Get him!"
As this command rang out the astonished pleasure seekers started a panic, as if an alarm of fire had sounded. There was a rush for every doorway, but every way of departure was blocked by stalwart guardsmen.
Billy was not among those who tried to break through the doors—he was dodging among the charging force sent in by the loud orders to "get him."
Click! The room was suddenly shrouded in darkness, penetrated a little distance only by the lights beyond the entrance of the lounging room section.
The pursuing force, working from several directions, ran into one another's arms. The pianist, familiar with the place, leaped for the electric switch, and turned on the flood of light.
Everybody was present but the singer!
Henri had a perch on the keyboard of the piano, which he had sought to save a mad tramping on his feet.
"Set you to catch a weasel," sneered Roque, as the sandy-haired man stood staring at the shattered casement of the tall window overlooking an inner court of the hotel.
"He can't get clear away," retorted the sandy one.
"Stop him then," challenged Roque. "Don't stand there like a stoughton bottle."
The pursuers scoured the building from bottom to top, and every street and alley roundabout, but it was a case of looking for a needle in a haystack.
Roque was in a black mood. Once more baffled by his cunning chief adversary, the only one he acknowledged in his own class, and on his own stamping ground—it was a bitter dose for the master craftsman.
Did he remember how he himself had spread a web over Britain, woven so finely that even Scotland Yard could not see it? Yet he rebelled at the like cut of a diamond.
"Stir your stumps," was his peremptory address to the boys, and they trotted to catch his long stride out of the hotel.
The sidewalks on both sides of the street were crowded with curious onlookers, attracted by the reported doings inside.
Roque bucked the line like a football star, and Billy and Henri followed in the cleared space without special exertion.
"He doesn't care whom he pushes," observed Billy, as he listened to angry protests along the line of travel.
Both of the boys were eager to talk over the latest disappearing act of that wonderful Anglin, but not so anxious as to take chances with Roque in earshot.
The secret agent turned into a silent side street, and stopped before a heavily grated door in the gloomy front of a solid stone building that was a skyscraper in height. Reaching through the grating, he evidently opened way of communication with the interior, for in a moment or two a glimmer of light splintered through the barred entrance, the ponderous lock creaked, and the door swung back on its massive hinges. A skull cap and a gray beard showed behind the lamp shining in the doorway. Roque pushed the boys ahead of him, and their closing in was marked by a clang behind them.
They followed their guide through a long corridor and into a modern high-power elevator, that shot noiselessly upwards. It was a circular room into which they stepped, the very tip of a tower, and a wireless telegraph apparatus was there in operation.
"How is it working?" promptly questioned Roque of an operator who was off his turn, and relieved of his headgear.
The man jumped to his feet, all attention, and replied: "There's been hardly a break for an hour, sir."
Here was one of the hidden intelligence stations that accounted in part for Roque's ability to get searching and quick information. That he should initiate the boys into his particular secret service methods indicated a determination that they should never get away from him.
As Billy said to Henri at a chance moment, "He thinks we are booked for a life job as his air chauffeurs."
They were not aware as yet that in the extensive grounds, housed at the water's edge, was the seaplane in which they had recently traveled so far, and in addition a big biplane and two monoplanes were in hangars ready for service. Also the most speedy of steam launches rested at the private wharf.
Roque was a recognized genius, like every cog in the German wheel, absolutely thorough in his methods, and the means placed at his disposal were practically limitless.
Billy and Henri had climbed into the steep embrasure of a tower window and were enjoying the magnificent view spread out before them.
"How about my imagination now?" Henri was recalling exciting incidents in the hotel. "Didn't I get the figure of the sandy man as a spotter?"
"I think you did," admitted Billy. "But," he continued, "I didn't take much stock in the idea until I saw the revolver in Roque's hand. Then I knew that the fat was in the fire."
"I gave Anglin the cue to beat it, and I did the trick by breaking into that Rhine song," exclaimed Henri. "Yet he never made a move until the yell of 'get him,' and I thought the jig was up, sure. He's the coolest hand in the business, that fellow."
"Some of these days, maybe, he'll fall a little short in one of those getaways, and that will mean a tumble into six feet of earth."
"Not he," stoutly maintained Henri, "he's the regular man with a charmed life. Say, I can't help laughing even now when I think of Spitznagle calling 'Conrad,' and the expression on Roque's face."
Billy gave Henri a kick on the foot. Roque was approaching with a sheaf of telegraph messages in his hand.
"What are you boys jabbering about? I want you to go down to the wharf with Albert and get the seaplane in trim. I'll join you in half an hour."
Albert, a strapping youth, with the breezy way of a sailor, guided the boys across the grounds to the hangar, and watched with interest the making ready of the airship.
"That's not my kind of a boat," he briskly stated, "but I'll be bound if this kind of craft didn't give us submarine workers a Christmas surprise. Ever travel in a submarine?"
"We had a ride in one that we will never forget," replied Henri, as he applied the oil can to the big motors.
Billy, busy with the steering gear, was not expected to answer, as he did not understand the question.
"It is all a question of ups and downs, anyhow," went on Albert, "bombs from above and torpedoes from below."
This trade discussion ended with the arrival of Roque, who had severed himself from style and was again in aviation attire.
"Now, my carrier pigeons, you are in for a homing flight, that is, Hamburg; and it may be some time before you again get a breath of this port."
With this assurance the seaplane was launched and took the airline for Hamburg, leaving Albert to his own devices.
The travelers soon had sight of Zorn's ever-ready grin at the home of "the well-known tradesman."
"We've been through a lot since we were last hauled out of these feathers," remarked Billy, as he bounced into the bed pillows that night.
Happily, "coming events do not cast shadows" for sound sleepers.
Roque had departed for the city before the boys charged into the breakfast room.
"He has gone to the store," announced Zorn, who uncovered his teeth an extra inch, in compliment to his own humor.
"Let's go over to see Lieutenant Hume," proposed Billy, after breakfast.
"Just the ticket," agreed Henri, "I'm crazy to get a peep at the old flying quarters again."
But Zorn objected to any move that Roque had not ordered.
The boys had to be satisfied with the prospect, for to run against Zorn would be akin to tackling a mountain.
When Roque returned, sure enough, he was again playing the merchant—horn, spectacles, and all.
"Ah, young sirs, kindly waiting for the weary worker?"
"Same old blarney," muttered Billy.
Zorn chuckled as he relieved the "merchant" of his hat and overcoat.
"Some time ago I believe I told you that here you were only balancing on the edge of the great empire, and there might be an opportunity for you to see much more of the country. The opportunity is at hand. I have been called by trade interests further afield, and as I cannot consent to a separation, you will continue as my companions."
In his hour of relaxation, Roque really enjoyed this sort of word play, and he eyed the boys to see if they appreciated the fact that all of the best actors were not on the stage.
He was sure of Zorn's sincere appreciation. This man had seen the chief in many parts.
Henri accepted the cue, and, with a profound bow, and a hand on his heart, replied in kind:
"My dear Herr Roque, we would grieve if you left us behind."
"What of you?" Roque turned to Billy.
"Oh, anything goes with me." The boy from Bangor always hit straight from the bat.
The last evening of many in Hamburg was a very pleasant one to the boys. Roque's intimate knowledge of London and Paris was displayed in entertaining way, with no reference to his own exploits as the cleverest conspirator that ever invaded court and palace. He expressed regret that he had never seen America, and induced Billy to tell about Boston and Bangor.
It may also be recorded that with this evening the boys unconsciously said good-by to the character of the Hamburg merchant. They went far with the many-sided man, but never again saw him in the rôle imposed by this big city on the Elbe.
When the boys retired they left master and man—Roque and Zorn—conversing before the fire. With the coming of the morning, the journey to the unknown began, and the Aëroplane Scouts had no idea of its purpose or their assignment in the new sphere of action.
That it would, however, include further conquest of the air they might have guessed.
It was a great day for the boys when they set foot in imperial Berlin, with its palaces, art galleries, museums, parliament building, monuments, magnificent parks, and over all its martial spirit.
Roque, by which name, it might be mentioned, he was not known in this heart of the empire, soon demonstrated to his charges that he was the man higher up by his manner of getting about, and the high cost of living had no worries for him.
"Who'd have thought that we would be hitched up to a ten-time winner like this?" Billy was content for the time being to be allied with power.
Among the many who answered the summons of Roque in the intelligence bureau, the young aviators were most interested in a score of blond, blue-eyed, well-set-up Saxons, renowned as Zeppelin navigators, who were destined to guide the "terrors of the air" in furtherance of another raiding plan taking form in the fertile brain of the eminent promoter of trouble for the enemy.
While the boys had faith only in the heavier-than-air machines, they conceded that the risk taken by the Zeppelin crews entitled the latter to brush elbows with the crack flyers of the other kind of bird craft. It was also true that when a Zeppelin got anywhere it was a tremendous factor in war. And it was no question but that the Fatherland had gone Zeppelin mad.
Woe betide the hostile airmen who dropped the bomb on the Zeppelin works at Friedrichshaven if Roque had the means of catching them. It was only another score that he had marked up against Ardelle, whom the master agent of the empire charged with planning this destructive performance.
"Roque said he was going to show us where these gas cruisers grow," Henri advised Billy one evening, getting this news while his chum was engaged in an argument with a Zeppelin worker.
"Something I've been wanting to see," exclaimed Billy. "I owe something to a Zeppelin, even if it is like a balloon."
This last was a sort of side swipe at the man who had been on the other side of the argument.
"There is one thing sure, these dirigibles can't camp out." This was Billy's first remark in Friedrichshaven.
He was peering into a big steel-framed shed with a glass roof which housed one of these grim engines of the air—a great cylinder flanked by platforms. This newest of the huge airships was about the length of a first-class battleship, and the opinion of the young aviator that it could not drop anywhere and everywhere like the aëroplanes he drove was not a prejudiced one.
When Henri had a look at the powerful motors he was impressed with their capacity to drink up petrol at a most appalling rate.
"What's her top speed?" he asked one of the big fellows who had traveled over from Berlin with them.
"Forty-five miles in the calm," was the reply.
"Gee!" exclaimed Billy. "We could get a seaplane home for breakfast while they were waiting supper on you!"
"Yet," claimed the Zeppelin expert, "it's the car they're all afraid of."
"It certainly does look like a scaremark," admitted Henri, who remembered a certain evening on the Belgian coast, when he was one of the company aboard a stranded hydroplane dragged ashore by the swinging anchor of a Zeppelin, which loomed overhead like a cloud, and buzzed like a million bees.
A gang of at least a hundred men swarmed about the shed when the order issued for a trial trip of the new super-Zeppelin, a sample of the fleet in course of building, and Roque carefully noted every detail of equipment.
The gas chambers were fed with pure hydrogen, no common coal gas, and many thousand cubic meters were in the flow of this one envelope filling.
"Guess they'd have to carry a hydrogen factory around with this outfit to keep it going," observed Billy, as he noted the elaborate process.
"Not that bad," advised the man at his elbow, "this gas can be transported from the factory in cylinders under pressure."
"Just think of it," put in Henri, "I heard them say just now that it took thirty gallons of petrol an hour to buzz these motors."
"Biggest thing I know in the air business. I wish Captain Johnson could see an expense bill like this. He'd have a fit." Billy would, indeed, have counted it a red-letter occasion if his old friend, and the boss airman of Dover, were really at hand to take in this show.
To go aloft in an airship about which they were not thoroughly posted was a brand-new experience for the boys, but they were not in the least degree like the proverbial cat in a strange garret. It was easy riding, and none of the guns pointed their way. Billy carried a memorandum of a British military biplane, with a record of 10,000 miles, which Henri and himself had once patched up, that had been hit by 250 rifle bullets and sixty fragments of shells. He wondered if the immense craft in which they were sailing could have floated with, proportionately, about ten times that amount of lead poured into her. But Billy, of course, did not then know much about Zeppelins.
Roque, however, was eminently well satisfied, particularly with the improved method of distributing explosives where they would do the most harm. The airship had a special armored compartment for bombs near the propellers and a big gun mounted in front to destroy aëroplanes. "Get a fleet of these over the English channel," he proclaimed, "and somebody would think that hell had been moved upstairs!"
"I'll say this much," announced Billy, "I'd take an ocean voyage for my health if I knew when they were coming."
"But if the fighting crowd over there had the date and the hour, I'll promise you that the reception your fleet would receive would be warm enough to boil an egg." This was Henri's prediction.
"We never advertise," grimly remarked Roque.
When the Zeppelin had completed her trial trip and had again been housed by the small army of workmen, Roque informed the boys that he was going to give them the chance on the morrow to show their mettle in a biplane test, which was to decide the relative merits as to the speed of two special designs.
"I am going to put you up to jockey the machine that I favor," he said, "and, mind you, the aviators that will drive against you are among the finest in our flying corps. I always pick my men by personally knowing what they can do in any line of action. They seldom fail me, and it is with you to make good."
"We're going some, Herr Roque, when we come up to your standard," replied Henri.
"See that you are 'going some' at the finish of the race to-morrow," laughed Roque.
"It will be because something breaks if we don't hit the high mark," assured Billy.
"Go over and size up your winged steed," directed Roque, pointing to a hangar across the field. "Show them No. 3"—this to one of the attendants.
"This is no mosquito," announced Billy, after a view of the fine lines of "No. 3."
"Speed there, I tell you, old boy," was Henri's comment as he walked around the rigging, "and carrying armor, too."
In an hour the boys had fully comprehended all the new features of this up-to-the-minute machine. They had been builders themselves and knew a good stroke of the business when they saw it.
Returning across the field, Billy and Henri were introduced to the rival aviators by Roque. The German airmen were a jolly pair, and showed by the professional courtesy they exhibited to the two of their kind that the coming contest was wholly a friendly one, and the results to be of value to the flying corps.
"No. 2 is a little older than your machine," was the greeting of one of the Teuton experts, "but it can hold its own."
Roque, speaking for his champions, gaily disposed of this claim:
"Keep your eyes open to-morrow, Fritz, or you will get lost somewhere in the rear."
"No fear, sir; there are no cobwebs on No. 2."
"What are they talking about, Buddy?" asked Billy.
"They just think they are going to beat us, that's all," interpreted Henri.
A bright clear morning presented itself for the aërial race, and Lake Constance lay like a broad mirror under the sunlight. The course was set due north and straightaway for twenty miles, and the turn fixed at a high point called Round Top, upon which, Roque informed the boys, a tall flagstaff had been mounted.
There were no preliminary trials, for both machines had been carefully groomed, and each was as fit as a fiddle.
With the aviators up the biplanes scudded down the field for the rise, and got away upon almost equal terms, the German drivers slightly in the lead, through better acquaintance with the lay of the ground. They trailed a yellow streamer, while the boys floated a band of black.
The ascent reached 2,000 feet, when the machines darted north like arrows. Roque and a group of officers about him followed the speeders through field glasses.
"They would run a swallow to death," remarked the secret agent to the aviation lieutenant at his side.
The aëroplanes had dwindled in the vision to mere specks, and there was no telling which was in the fore.
"Ah, they are headed back!" cried Roque. "Now for the show-down."
The glasses revealed the specks moving twin-like, and such was the terrific onrush that the crowd surging in the field soon caught a view of the contestants in growing size.
One enthusiast shouted: "Fritz will shut them out!"
But the glasses did not uphold the prediction. The machine with the black streamer was evidently using the reserve power that had been claimed for the newer make, and Henri was getting the best out of it. Yet the first-born craft was being handled in a masterly manner, had plenty of go to spare, and five miles still rolled between the speeders and the finish flag.
Now four, and the machines were bow and bow; now three, and the yellow band flapped a few feet behind the black; now two, now within the mile, and the whirring of the motors audible to the nerve-strained watchers below—then the close finish—and the white-faced pilot crowned victor was Billy Barry of Bangor, U. S. A.!
When the aëroplanes made landing, Roque pushed through the crowd and favored the Aëroplane Scouts with a forcible slap between the shoulders.
The victors were quick enough to extend hands to the vanquished.
"My friend," cried Billy, giving Fritz a warm grip, "it was only fifty feet, and it was the new motors that did it."
Then the crowd cheered, while the efficiency committee agreed with Roque that "No. 3" was the machine to be many times duplicated.
"That was something over a mile a minute coming back, I guess," figured Billy.
"The fastest heavy craft I ever sailed in," was Henri's expressed belief.
"I think you youngsters could make a living here if I were to bounce you," said Roque, who had been talking to some of the factory chiefs. "But you are hooked to my train for a while yet. And that reminds me that the mentioned train starts in the direction of Austria in the next two hours. Vienna is not a slow place, you will find."
As Roque was likely to jump anywhere at the drop of a hat, the boys in his company had long since lost the emotion of surprise.
Perpetual motion had become a habit with them.
In the Austrian capital the travelers encountered many invalids from the front, men who limped a little, had an arm in a sling, or a bandaged head. The Viennese on the surface did not seem to be greatly impressed by the tragedy of the war—evidently becoming used to it—yet the determination to fight to the finish, while not as grim as in Berlin, was there, nevertheless.
Another thing that impressed the boys was that here foreign terms were still much in evidence—French and English. In Berlin it was different.
As Billy said, "we're in a better mixing town." He and Henri were told that quite a number of medical and art students from America had decided that Vienna was safe enough for them, but Roque kept his airmen close under his wing, and they had no opportunity to pass even the time of day with any of the U. S. A. crowd.
They had no present desire, however, to attempt a bolt from Roque and did not believe, anyway, that their detention was just then seriously affecting their health.
"Time enough to run," was Billy's philosophy, "when his nobs begins to kick in our ribs."
They were seeing plenty to keep them interested, the arrival of sleeping-car trains bringing the wounded to the capital, the movement of troops bound for the Polish or Galician front, the daily sights of the Ring and the Kartnerstrasse.
Roque, as usual, was up to his eyes in war business, ever behind the scenes but ever moving, for there is close military coöperation between Germany and Austria-Hungary. All interests related to the war have been pooled—one empire gives to the other what can be spared. The king-pin of secret agents from Berlin served a purpose wherever he went.
He sat in no open councils, but privately conducted many of his own, was constantly receiving and dispatching messages, and the devices he originated to aid his disguised subordinates burrowing for information in hostile territory were too numerous for detail. These latter operations were not accompanied by band music, for officially this live wire had no identity.
"If that man took a pot shot at the ocean you would never know in what direction he was aiming unless you happened to see the splash." Billy was not far from being right in the summing up of Roque's methods.
Within the next hour the boys "happened to see the splash."
A uniformed messenger handed Roque a telegram. The secret agent hastily read it, and sprang to his feet, his eyes aglow with triumphant satisfaction.
"I've got Mr. Ardelle in a stone box at last!"
The boys in silence watched the secret agent as he further displayed his gratification over the news conveyed in the telegram by snapping his fingers and slapping his knees, completing the performance by vigorous puffing of a big black cigar, of which brand he always carried a plentiful supply.
Billy and Henri were just aching to learn more about the reported capture of Anglin (Ardelle), just where the "stone box" that held him was located, and how the "smiling sleuth" had happened to run into a net that he could not break through.
But they were well aware that it would not be a bit of use to seek the eagerly desired information in advance of Roque's disposition to give it, and they did not dare openly to show personal interest in the matter.
It was not until the master plotter had burned his cigar to inch measure that he thought to address the lads, fixing expectant gaze upon him.
"They jugged the fox in Alsace, on the way to his home den, and filled up, I suppose, with some choice morsels to regale the enemy."
"Maybe it's another case of 'now you see him and now you don't.'" It was Henri who plucked up courage to say this.
"Not this time," insisted Roque. "He is tightly in the toils, and never a chance to show his cunning. His course is run."
It soon became evident that the speaker proposed to be "in at the death," as fox chasers call the finish.
In less than two hours Vienna, the city gay and unafraid, was behind the three travelers, and their next goal the imperial territory of Alsace-Lorraine.
Into Lower-Alsace, on the last leg of the journey, Roque and the boys took to horse, with cavalry escort. They were again on real fighting ground.
Henri picked out of a conversation between Roque and the captain of the troop the words "Homberg castle," later that a group of important German officers resided there, and still later that within those walls Anglin was a prisoner.
Billy was immediately posted by his chum as to the situation.
Upon arrival at the castle, Roque, in that mysterious but effective way of his, established his footing as a privileged guest, and his first move was to pass the guard at the door of the strong-room, where his chief rival in the art peculiar was confined.
The boys without reprimand were close at the heels of the German agent.
Anglin was sitting on a bench, under the checkered light of a high, barred window. While his face showed harsh lines of great strain, the inevitable smile was in his eyes. He arose instantly from the bench, and bowed gracefully to the foe who confronted him.
"Monsieur, you are welcome." This to Roque. Upon the boys he bestowed not the slightest recognition.
Roque, not to be outgeneraled as a diplomat, inclined his head in return.
"I came a long way to visit you, sir," he politely stated, "and would have regretted had you felt otherwise than you have intimated."
This fencing with buttons on the foils was soon succeeded by the sharp points unprotected.
"Ardelle, the longer the breath is in you the more you can tell; is the breath worth the telling?"
"You speak in riddles, Monsieur," quietly replied the prisoner.
"Do you deny that you are Ardelle?" demanded Roque.
"Am I now on trial?" was the counter-question.
Roque extended a menacing finger. "Have a care, man!" he thundered.
The prisoner calmly ignored the growing wrath of his arch-enemy, shrugged his shoulders, and with a wave of the hand indicated that continued argument was useless.
"You will have until to-morrow morning to decide whether you will accept me as an advocate or an accuser."
The Frenchman turned wearily toward the window, and with his hands folded behind him stood watching through the bars the little gray cloudlets pushing their way through the blue expanse of the sky. It might be that this view would not concern him after the morrow. He was thus engaged when Roque stamped his way out of the room. Henri would have paused in the hope of one look from Anglin but the latter seemed wholly unconscious of the presence of the lads.
Under the steely exterior of Roque, the milk of human kindness had not wholly curdled, for he sadly said, half to himself and half to his boy companions:
"He must expect no more than I could expect; when we fail we fail alone, and so alone must we suffer."
It was about two o'clock in the morning of the day when Anglin, or Ardelle, was expected to read his fate in the eyes of those assembled as a military tribunal. The identity of the prisoner was, no doubt, fully established, for the boys had noted the presence in the assembly hall earlier in the night of the sandy-topped man who had started the hue and cry in the Bremen hotel, where the French sleuth was posing as a public singer.
Billy and Henri were tossing in uneasy slumber. The only sounds inside the castle were occasional snores from adjoining apartments and from the outside the whinnying and stamping of the cavalry horses.
Suddenly the quiet was shattered as if by a thunderbolt. The boys literally tumbled out of bed, gasping from the shock. A blinding flash at the windows and another crash.
Soul-shaking cries of "fire!" resounded throughout the building, and through the halls swept volumes of smoke.
The celebrated ancient furniture in the castle, it having been the summer residence of French nobility, was fine food for flames, and the red destroyer soon raged in conflagration.
Crash after crash, and with each concussion myriad sparks shot through great holes in the castle roof.
Bombs were being dropped from aloft.
The boys hastened with other occupants of the upper floors to the broad staircase in front of the structure. There they paused, elbowed against the wall by those pressing from the rear. There was no wild confusion or panic behind them, however, such as might have ensued under the same terrifying circumstances with other than trained soldiers involved. When Billy and Henri took to the wall at the head of the staircase it was a voluntary act on their part. The same thought with both had impelled the pause:
Had Anglin been released from the fiery vortex or still restrained by iron bolts and bars?
The room in which the captive was held faced a gallery running at right angles from the main stairway.
Pulling their jackets up and over their heads, the boys plunged through the wall of smoke on mission of rescue—a mission without result, for the door of the place of confinement was wide open, and no one was there.
The rescuing party of two then turned their intent upon themselves, and none too quickly, for they had hardly won safety when the castle enclosure was wholly enveloped by consuming flame.
Farm buildings adjoining were also ablaze, and the wide highway stretching away to the east showed whitely in the glare.
In the red canopy overhead winged shadows whirred and whirled, dipped and leaped.
Billy and Henri proceeded down the road to escape the growing heat and rolling smoke. When the roaring of the fire had somewhat lessened in their hearing, they detected a familiar hum, just ahead and closing down beyond the border of the rising mist of the morning.
As aviators, the boys were instantly aware that an aëroplane was working near and the proof was immediately furnished by the appearance of the aircraft itself, swooping into the circle of illumination, skimming close to the surface of the highway.
The lads sprang forward to greet the aërial visitor, and as they did so a tall figure, hatless and coatless, leaped from the cover of a ditch nearby, ran like a deer alongside the skimming biplane, and vaulted into the frame behind the daring navigator.
As the machine took the uplift, Billy and Henri were so close, and the fire-flow so vivid, that they plainly saw the faces of both the saver and the saved.
The man who had jumped into the machine was Anglin; the aviator was Gilbert Le Fane, the noted airman of Rouen, whom our boys had once followed in flight from Havre to Paris.
From the fire zone there was coming a hurrying body of men, and rifles began to spit lead at the swiftly rising aircraft. Too late, though, to reach the height attained by the biplane. A shrill yell of defiance floated back on the breeze of the morning, and deep and heavy were the expressions of baffled rage by those grouped in the road below.
Roque and the sandy-haired assistant could be heard above all the rest.
The boys were again in the rôle of innocent bystanders.
When the sun later replaced the flames in lighting up the sky, not a trace of the French airmen could be sighted, save the marks of their raid—the blackened ruin of the castle and smouldering remains of the adjoining buildings.
Investigation instituted by Roque related solely to the escape of the prisoner. To put a quietus on his rival had drawn him from afar, and here again the elusive Frenchman had been jerked out of his clutches, this time into the very sky.
With the fall of the first bomb the single night guard over the captive had drawn the bolts that he might be ready to quit his post upon first order with the Frenchman in close custody. The second bomb so stunned the guard that he knew no more until regaining consciousness in the rear courtyard outside. He could only account for his presence there by the belief that the man over whom he had held watch had picked him up and carried him out of danger. There was a back way that could be traveled, smoke hidden, without observation.
"But how about the aëroplanes dipping just at the right time and place to carry him off?"
This was the point that especially puzzled Roque.
A farmer boy, listening, open-mouthed, to the questioning, offered a solution.
"You see, Monsieur," he bashfully explained, "it was a ghostly noise that was making between the big noises, like the wind blowing through the neck of a bottle stuck in a knot hole. I heard it in the road, a long way."
It occurred to the boys that this distress signal must have been given before they got away from the roar of the fire, or while they were probing the smoke in the gallery to reach Anglin.
"They were flying mighty close down and could probably hear a howl like that, if they were listening for it and knew what it meant." This opinion was advanced by Billy.
"I don't much believe they could hear a call from the ground, unless it came from the business end of a gun." Henri was the doubter.
"It is no use to argue," said Roque. "The fact remains that the air fellow had his bearings, and he got the lead from somewhere. I am not giving him credit for being a mind reader."
"That reminds me, Mr. Roque," remarked Billy, "that we might test this bearing business by a little air trip somewhere and soon."
"I have just such a thing in thought," grimly advised Roque, "and I will warrant that you will hear a few ground sounds before the quitting minute. We are going to take a down look at Belfort."
Now Belfort is a French fortress, where the soldiers in red and blue had been finding security every time they were rolled back from the plains of upper Alsace.
A tremendous amount of gunpowder had been burned on the flat ground in front of this stronghold, and our boys were in for a smell of it—something that would recall perilous travel with Colonel Bainbridge and Sergeant Scott in previous campaigns.
A wire to Friedrichshaven had started on the way the makes of biplanes that Billy called "Roque's best bet" since the day of the famous race over Lake Constance.
"Business will soon be looking up," joked Henri, when he heard of the order for the shipment of "No. 3's."
The presence of Ardelle in this region, extreme southwestern Germany, had raised suspicion in the mind of Roque that some special demonstration was brewing, and the lurid performance of the French airmen in blowing the roof from over his head served to further elevate the confirmed idea that trouble and the French agent always traveled together.
Roque was not here to mix in the actual military operations—that was not his business, but he was ever open-eyed on the trail of the boss gamester on the other side. He had expected this time to put his rival on the safe side of the ground, but spades did not prove to be trumps.
Somewhere in the gap of Belfort, as the valley south of the Vosges mountains is popularly known, Ardelle was, no doubt, preparing for another comeback, and Roque was scheming to meet him halfway.
There was no chance to get under the guns of the frowning fortress beyond the frontier, so the only way to size up the situation was to go over them.
Here was where flying experts jumped to the front.
With the arrival of the biplanes from the factory, the Boy Aviators were kept busy with brief test flights over valley and plain, awaiting the convenience of Roque for the wider sweep he was planning. It developed that the boys were expected to navigate separately on this occasion, Billy to pilot Roque himself, and Henri to be accompanied by one Renos, who had been awarded a service badge of honor for his work as an aërial observer in giving first warning of the advance of a French division against Burnhaupt, which saved the day for the Germans.
"The seaplane is the rig for weight carrying," exclaimed Roque, in accounting for this assignment, "but these machines, as you know, are solely in the speed class, and it is many chances to one that we will be compelled to tax every ounce of power before we get through. So we have no use for deadwood."
Renos, who was to sit behind Henri, was the silent man of the expedition, as far as talking was concerned, but when it came to be up and doing he could be counted on to the limit. He was a human route-box of the Sundgau, the fighting territory, and very much at home in a flying machine. When the two machines one morning flew over the German frontier, in compliance with the "ready" order of Roque, Renos' knees were crossed by a wicked-looking rifle, and of the party he was the only one armed.
Billy, observing this war-like figure, asked Roque if he expected to get into close quarters on this trip.
"Not unless some of the bomb-throwing crowd that scarred the landscape the other night should cross our path," replied the secret agent.
As Renos was the qualified guide, the biplane bearing him went to the front, and Henri received overshoulder directions as to the course to be maintained.
The apparent reason why the German expert did not pilot the craft himself was that he wanted a loose hand in case of emergency, and a free eye for the panorama below. He was satisfied, too, that one as good as the best was doing the steering.
Henri was instructed to keep a respectful distance from the near mountain peaks, where the French had mounted artillery, for one round from these guns, close enough, would have ended the flight and the flyers there and then.
But Roque and Renos kept constant vigil with glasses, and Billy wondered that the pair did not get a crick in the neck with all the head-turning they did.
A sharp order advised the pilots to send the biplanes farther aloft, and circle. The French fortress of Belfort could be seen directly underneath.
The aviators well knew that an explosion close to an aëroplane is often sufficient, through the force of the air concussion alone, to bring it down, and they knew they could not chance a close shot from the long-range guns in the fort.
Though the machines now evoluted at greater height, the powerful glasses enabled the observers to plainly distinguish the movements below.
It was quickly manifested that the garrison lookout had become aware of the aërial visitation, and that they did not approve of the color of the hovering aircraft.
A couple of smokeballs ascended and burst in the center of a cloudrack far to the right of the machine. Renos broke his record for silence with a shrill cackle.
"Save your powder, you numbskulls," he shouted for his own satisfaction.
Roque seemed oblivious of the gunplay below. As the biplane described great circles over the fort, he kept his glasses steadily aimed at a point in the enclosure over which the flag was floating.
The men who emerged from the officers' quarters all wore the French uniform.
Roque had evidently cleared up a disturbing point in his mind as he muttered something about a "fool story," and "I might have known there was nothing to it."
Having satisfied himself that it was still an independent little war at this remote point from the main field of operations, and that he had been misled by some advices previously received, the chief observer passed the word to his pilot to back-track, at the same time giving signal to the companion biplane.
As the machines swung around for the return flight, and drew closer together, Renos gave a megaphone yell through a hollow formed by his hands:
"Speed for your lives, they're on the wing!"
Above the gentle slopes on the west, leading to the summit of the mountain ranges, aircraft had arisen, looking, at a distance, like black dragonflies.
At the same moment, the invading biplanes also had a reminder to hurry from the fortress they were leaving behind.
A shell burst seemingly quite close to the machine Henri was driving, and the craft dipped far to one side.
Billy's heart beat up to his throat when he saw the break in the flight.
But his was an exulting cry when the momentarily stricken flyer righted, and bored ahead.
"Glory be!" hoarsely rejoiced the boy from Bangor, when his chum again drew to the upper level.
Seventy miles an hour was the clip of the fleeing biplanes, and no less speedy the onrush of the aircraft from the slopes.
"Steady, and a little to the right," Renos instructed Henri.
The observer was resting the rifle barrel on the rigging, awaiting a broadside target.
Sping! One of the attacking aviators was first with his rifle, and the bullet nicked the armored side of the German craft. Sput! Henri heard an angry exclamation behind him, and shifted an eye long enough to see that Renos was nursing a bloody wrist on his knee.
"How hard are you hit?" was the anxious question of the young pilot.
"Nothing to kill," replied the observer, as he used his uninjured fingers and his teeth in knotting a handkerchief above the wound so as to compress the severed artery.
With the utmost calm he then deliberately used his left hand in rifle aiming, and sent a bullet into the nearest hostile machine.
Whether the shot crippled the pilot of the leading pursuer, or whether it was the menace of the heavy howitzers on the German frontier, which was now of short approach—the French flyers suddenly ceased to be aggressive, and with a parting salute of rifle practice, turned back toward their mountain station, while the German machines dashed across the line of safety.
Upon landing Billy indulged in a sort of war dance around his chum.
"Thought you were gone that time, sure, Buddy," he cried, "and it was simply great the way you pulled out of the hole."
"I guess I was stunned for a minute, as though somebody had hit me with a hammer," explained Henri, "but when I found the controls were still working, it was a bracer, I tell you. And if there isn't a cool head" (nodding toward Renos, who was inspecting his wounded wrist) "I never saw one. He stretched his arms over me ready to take hold if I failed to rally, and did it as a matter of course. Not a tremble about him, either."
"What do you think of the No. 3's now, boys?" queried Roque, when he had dispatched Renos in search of a surgeon.
"They're dandies, all right," promptly agreed the happy pilots.
"They will do to hunt trouble with, anyhow," laughed the secret agent, who was immensely pleased with the flying achievements of the day.
Roque, pluming himself with the idea that, though he did not hold Ardelle when he had that artful dodger under his thumb, he had at least chased his rival out of the empire; and, having also eased his mind as to the report of a new element in the Alsace campaign, he was impatient in his preparation for departure. Master of detail though he was, the big moves only appealed to him.
A great battle was raging at Soissons, on the Aisne river, in France, and Roque had in mind an aërial journey north, and quick flight across the border to the scene of the fierce artillery duel, following the line of march of the mighty force under General von Kluck.
The crippled Renos was replaced in the observer's perch by an aviator known as Schneider, a very daredevil, and who was at first inclined to doubt that the boy with whom he was paired had sufficient skill and courage to pilot a military biplane in an active war zone. Henri very quickly convinced the doubter that he was very much older than he looked when it came to the fine points of aëroplaning, and, too, that when there was an emergency demand for "sand" the youngster had plenty to spare. Schneider had additional assurance of capacity when he was advised that both of the lads carried Roque's indorsement of efficiency.
It was a bitter struggle that the Aëroplane Scouts were to witness at Soissons, and six days of it had already passed. The earth was still dropping on many graves of the German fallen, and yet, sprawling in attitudes along the heights, in the deep-cut gorges of the plateau, and across the flat valley bed were French infantrymen in their far-to-be-seen red-and-blue uniforms, swarthy-faced Turcos, colonials, Alpine riflemen, and bearded territorials.
At staff headquarters, in the first officer that passed near them the boys recognized a familiar figure, no other than Colonel Muller, whom they had first met in far-away Texas, U. S. A., on the day of the record flight, and again in the hangar camp at Hamburg.
Billy impulsively stepped forward. "How do you do, Colonel?"
The officer instantly turned in his stride to inspect the speaker. "Hello, Boy Aviator," was his hearty greeting. "How under the sun did you ever get here?"
"Same old way," said Billy, "the airline, of course."
"And here's the other one," the colonel reaching for Henri's shoulder.
"By the way," continued the big soldier, "this must be a field day for flyers. Here, Hume, come and see what the wind brought in."
The officer addressed moved at quickstep in response to this invitation. It was the aviation lieutenant from Hamburg. He grinned from ear to ear when he laid eyes on his former charges.
"Can't lose you if I try," he exclaimed. "Have you enlisted with us?"
"No," laughed Billy, "we're still driving cars for the good merchant from your town," with the backward point of the thumb at Roque, who was engaged in close confab with a group of staff members near by.
"Did you blow in with Schneider, too?" asked the lieutenant. "I just want to say that you will bore a hole in a stone wall sometime if you train with that fellow. Nature didn't give him red hair without reason."
"Now that you are here," broke in the colonel, "you must not be allowed to get out of practice. I expect that one of you will have to give me a ride along the front before long. I have lost three horses this week."
"We'll do our best to oblige you, colonel," volunteered Billy.
It was no merry jest, that ride Billy gave the colonel!
At the time, the French retained a foothold north of the river at only one point—St. Paul—where the bridge from Soissons crosses, and this by a perilous margin, since the bridgehead was completely commanded by German artillery on the heights.
The battlefield entire covered a front of about seven miles, the center and eastern flank a high, level plateau rising steeply a couple of hundred feet from the valley of the Aisne. On the western side a deep valley ran northward, bounded on either side by turnpikes. An airman taking the big curve of the river would not be considered a good risk for a well-regulated insurance company.
But it could be done—and Billy Barry furnished the proof.
When the next day broke a bloody conflict was raging between the two turnpikes, the French infantry attack on German trenches preceded by a terrible artillery bombardment, a storm of shell and shrapnel.
Colonel Muller beckoned Billy to his side. They stood together on the heights from which the French had been expelled only the day before.
"My boy," was the brisk address of the officer, making a field-glass survey of the smoke-crowned landscape, "I am going down the line, and I am to do the distance in an aëroplane. Is it you or Schneider who will do the driving?"
"You gave me the first call yesterday," reminded Billy.
"That was my intent, and it still holds. I was only seeking to learn if you were of the same mind since that powder mill let loose down there."
"I well know the odor of it," stoutly maintained Billy, "and it doesn't weaken my knees."
The young aviator, accepting the matter as settled, hastened toward staff headquarters. "Mr. Roque," he excitedly called, "Colonel Muller wants to try one of the No. 3's this morning, and I'm to pilot."
The secret agent lifted his eyebrows as though surprised, but he really was not. The arrangement had already been made.
"Say, Buddy, this is rough that we can't both go; and suppose something should happen to you?" Henri had just realized that something was up, in which his chum was vitally concerned.
"Don't you worry, pard," consoled Billy, "it is only a little spin of a few miles, and we'll be back in no time."
"Wish it was me," sighed Schneider, for this firebrand guessed that it would be a red-hot journey.
As the biplane swept into the breeze current, trending to the river, which then was running brimful, and in many places overflowing its banks between the two armies, Colonel Muller advised Billy to keep the machine climbing for the time being, as a terrific fusillade was in progress in the distance of the next two miles, the shells hurtling through the air like lighted express trains. In the three steep-sided ravines that deeply notched the plateau on the east French troopers swarmed like bees, and at this cover the big German guns were blindly banging.
"We can't see much, Colonel, at two thousand feet," complained Billy.
"You would see nothing at all if we ran into one of those fragments of shells," coolly suggested the officer, "but never mind, you will do some diving in a few minutes."
Billy got the signal to dip at the juncture of the turnpikes, and to hold a level and lower course along the line of battle, marked here by infantry fighting between the seemingly crawling columns far below.
"Down!"
The colonel's order was peremptory, and Billy forthwith volplaned toward the earth.