Part 9

"Let them send all their available machines and pilots out east," he had said to Carl and Max, "then we will quietly slip across Europe to Ireland, where everything is ripe for the promised revolution."

"And the Schwarzwald?" queried Max.

"Oh, we will call there for a few hours en route," replied the pirate, calmly relighting his pipe, "The professor will understand our silence and inactivity."

So the third morning came, and Keane, whose anxiety regarding the still sleeping prisoners had been allayed by Sharpe, who smilingly confessed what he had done, now became fearfully uneasy as to the condition of affairs.

"For heaven's sake light that beacon again!" he ordered. "If assistance does not arrive to-day, all these secrets I have endeavoured to rescue will be lost."

"What will you do?" asked his companion, who was already applying a match to the pile of dried tinder and sticks.

"Blow the whole place up," he replied.

"And shoot the prisoners?" ventured his friend, slyly.

"No."

"What then?"

"Rouse them up, somehow, handcuff them together and take them away."

"Some job that," remarked Sharpe, looking up at the long thin trail of smoke, for there was still an absence of wind currents.

Even as he gazed into the sky, however, he caught sight of a tiny speck hovering at twelve thousand feet, and he almost shouted, "Aeroplane!"

"Where?" asked his startled comrade, whose nerves had undergone some strain during the past few days.

"Right up in the blue. There, can you see her?"

"Yes, I have her now, but she's very high. Can it be the _Scorpion_, do you think?" asked the senior.

"Cannot say yet. I'll fetch the glasses."

"Run for them, quickly! I cannot hear her engines at all. It must be the brigand."

"Ah, there, I hear the engines now, very faintly, though. Rolls-Royce engines too, thank God!" exclaimed Keane fervently, as he recognised the well-known sound, and knew that assistance had arrived at last, in the shape of at least one Bristol Fighter.

"It's all right, Sharpe. Cut off that beastly current. Tempest will be here in a minute."

"Are you sure it's Tempest?"

"Yes. Listen to that! Now he's cut his engine out again, and he's coming down. It's the chief right enough; I should know his flying amongst a score of aeroplanes."

The wires were cut off, a temporary landing-tee quickly rigged up on the ground, and frantic signals were made to the pilot, who was now rapidly coming down in sharp spirals.

A few minutes later the intrepid pilot flattened out above the tree tops, dipped again, banked steeply, and sideslipped almost to the ground, in order to get into the confined and narrow space which served the _Scorpion_ for an aerodrome. Scarcely had he landed when another machine, which had followed him from England, performed the same highly-skilled manoeuvre, and taxied up to the little group.

*CHAPTER XXI*

*THE COMING FIGHT*

"Good-morning, Colonel!" cried the two airmen, saluting their chief smartly, as he still sat in the aeroplane, looking not a little crabbed and sour, as he secretly swore at the infamous stretch of ground misnamed an aerodrome; then turned his gaze upon the two airmen who had appealed for assistance.

"Morning! So this is where you young cubs spend your holidays, while the whole world is ramping at me for not catching this infernal brigand. What have you got to say for yourselves?"

Keane was not at all put out by this dour greeting; he knew his chief too well, and admired him accordingly. Merit is not always accompanied by a bland and urbane countenance, neither do brains always accompany a white shirt front.

"I have that to say which will almost make you jump out of your skin, sir," replied Keane, "but we must somehow get these aeroplanes under cover, or properly camouflaged, for the _Scorpion_ may arrive any minute."

"Eh? What's that you say, boy?" exclaimed Tempest, leaping from the fuselage. "The _Scorpion_?"

"Yes, sir."

"Why, that is the name of your infernal raider, isn't it, Captain Watson?" and here the colonel turned and addressed his passenger, who was none other than the skipper of the air-liner which had been so roughly handled in the Hamadian Desert.

"The same, sir."

"And the professor, Keane? I sent you to track the professor. Have you found him?"

"He is our prisoner, Colonel," and Keane bowed stiffly, and pointed to the half-hidden hangar, where the two prisoners, who were now partly roused, had been safely secured.

An exclamation of pleasure and surprise broke from this dour-looking man when he heard this news, and his face became wreathed with smiles as he advanced to both Keane and Sharpe, shook them warmly by the hand, and said:--

"Thank you, my boys; I knew if it could be done you would do it, though I could ill spare you for the job. Yesterday my reputation was in shreds; I am to be charged with inefficiency, and a public enquiry is to be held. But you two wolf cubs have re-established my character; I can never thank you enough. Now lead on, show us this evil-minded genius! Professor Verne here, who has come in the second Bristol, with Captain Hooper, is anxious to see him. He may redeem him yet from the error of his ways, and it is vital that this secret of his should be in other and better hands, else it will always be a danger to the public."

So, whilst the party were conducted indoors, and shown the marvels of the modern house of alchemy, the two professors were introduced, and began a series of disputations, very embittered at first, as the German, though relieved of his bonds, and made as comfortable as the circumstances would permit, resolutely refused to give any particulars of his discovery, or even to display the slightest amiability towards his distinguished visitor, though they were not unknown to each other, and had even studied at Heidelberg together in their younger days.

Meanwhile, all possible steps were taken to prepare for the possible arrival of the _Scorpion_. The Bristol machines, after being carefully stowed away in a gap between the trees, were so camouflaged by branches of pine and larch that they presented but a very indistinct object from the air, and, unless their presence were known, might easily remain unobserved.

After some time had been spent in examining the highly developed and intricate mechanism of the devil's workshop, as the place was now called, the Commissioner suddenly turned upon his chief mentor, and said:--

"By the way, Keane, have you discovered any drawings or designs of this wonderful aeroplane? I don't see any amongst this pile of papers, and the professor does not seem inclined to help us at all."

"No, sir. We have searched the place carefully, but we have found nothing. Part of the machine could certainly be reconstructed from those spares, but all the important parts are missing. I have an overwhelming curiosity to see the machine, though, and hope that I may not have this pleasure much longer delayed."

"Then we have nothing but these photographs," returned the captain.

"Photographs?" echoed Keane.

"Yes. Why, I forgot to tell you in the bewilderment and excitement of the last hour, that Captain Watson here managed to secure three snapshots of the raider in mid-air, whilst his airship was being attacked."

"It was the boy Gadget who secured them, sir," interposed the air-skipper, anxious to give credit where credit was due.

"Oh, yes, Keane, I ought to say that it was a smart little beggar called Gadget, a stowaway, who really secured the photographs, and hid them away from the brigand. We must see that the little chap is properly rewarded when we return."

"Let me see the pictures, sir," requested Keane, eager to get some idea of his future opponent.

"Here they are. I have had them developed and enlarged. They should be extremely useful to us, as we shall shortly have to encounter this Sultan Selim, Air King of the Hamadian Desert, the world's greatest bandit, who had the audacity to send me this document by the captain."

And here the colonel, having retailed the whole story of the fight in the desert, showed the brigand's letter, which had been brought to London the previous day by the fast aeroplane which had carried the skipper of the air-liner.

Keane turned in amazement from the clear photographs of the phantom-bird to the brief, audacious letter of the phantom airman, and read as follows:--

"To Colonel Tempest, D.S.O., M.C.,

Commissioner of Aerial Police, Scotland Yard, London, W.C.

"Greetings from Sultan Selim, Air King of the Hamadian Desert. I regret to inform you that of late there has been a serious increase of aerial crime in these regions. The frequent passing of large airships containing mails and other commodities, without due payment of tribute to my customs officials, is a serious infringement of the laws of my dominion. This action not only imperils the liberties of small communities, but is also a crafty form of aerial brigandage, inasmuch as it defrauds my exchequer of its just and equitable revenue. This practice must cease forthwith, and I have taken steps to-day which, in my opinion, will render it unwise for this shameful trespass to continue. The bearer of this letter will give you further details of the action which I have been compelled to take on behalf of my subjects. Your five missing scouts will be found between the wells of Nefud and the Hedjaz coast. I have destroyed their machines as a salutary warning to future violaters of these my dominions."

Keane could scarcely restrain a smile when he laid down this wily, half-humorous, half-threatening epistolary from the aerial pirate.

"What do you think of it?" asked the colonel.

"It's a topping letter, sir, but I think he's trying hard to be funny, this von Spitzer, as you call him. A German with a sense of humour, sir, that's the best way to regard him," replied the airman.

"Humour indeed!" rasped out the colonel, becoming ruffled. "It's confounded impudence, and worse, when you remember that, apart from the damage to the airship, which is considerable, there is a net loss of specie and other valuables--to wit, the Maharajah's jewels--which is estimated at a quarter of a million sterling. I only hope and pray that we may encounter and waylay this bandit before he does any more damage. The deuce only knows what he'll do next, or where he'll go."

"Ireland is to be the scene of his next adventure, sir," remarked Keane.

"Ireland?"

"Yes, sir."

"Are you sure?"

"I heard the professor say so. They are to work hand in hand with the revolutionists there, and stir up strife which will make that unhappy land a still greater thorn in the side of Great Britain."

"Just what I feared!" exclaimed the now irate commissioner. "That explains partly those mysterious messages and rumours floating about Dingle Bay, and unfortunately I have had to withdraw nearly all the aerial police from that quarter to send them out east."

"You might as well recall them, sir."

"Why?"

"The raider has left the Hamadian Desert by this time, and is in hiding somewhere, but will call here on his way to Ireland."

"H'm! We're being thoroughly fooled, and if you hadn't found this demon's nest I should have gone mad. At any rate I should have been compelled to resign my post."

"Still, public opinion had to be satisfied, and you sent the patrols where the public demanded that they should be sent. Besides, if you recall them now, this raider will probably pick up your messages and change his tactics. I can tell you this, Colonel, that while he can get his necessary supplies of uranis, and a few extra spares from the workshop here, this von Spitzer intends to carry out his mad policy of destroying the civilized world by piecemeal. It is all part of a great plan to save Germany from the evil consequences of the Peace terms. But, whilst we hold this citadel, and retain these two men captive, his activities are limited to his present supply of this secret element--uranis."

The colonel swore under his breath, and went to examine the prisoners, to make sure that there was no chance of their escaping, for he felt the truth of Keane's words. He now felt grateful that the airman had not responded to the message for his recall, although it had amounted to a serious breach of discipline.

"Ah, well," he said at length, "it only remains to capture this raider, and the whole system of their clever and daring attempt to convulse the Allies, break up their international system of mail transit, stop the intercourse of civilized nations, and cause a world revolution--all these things will fail."

So their efforts were redoubled to make preparations to capture the wonder 'plane, should it descend on the aerodrome. A couple of machine guns were found, and mounted, under the charge of Sharpe and Captain Hooper, though the skipper of the airliner pointed out that the _Scorpion_ carried bullet-proof armour.

"You will need to hit her in a vital spot," he said, "so that your first burst may be your last, or she will be up again like a helicopter."

"Then we must have the two Bristols ready," urged the colonel, "though it's a deuce of a hole to get out of with this new type of a Bristol Fighter."

"And the petrol, sir?" asked Keane, who, was rather anxious on this point, for he hoped that the _Scorpion_ would become his victim in the coming air fight.

"There may be sufficient for another two hours, certainly not more."

"That means unless the _Scorpion_ chooses to stay and fight, she'll simply leave us."

"Von Spitzer will fight unless I stop him!" called out the professor from behind the curtains, where he was confined under the charge of his colleague of other days, for he had been listening to the conversation.

"So much the better!" replied Keane, tartly.

"And when the fight is over there won't be many of you left alive to tell the story," came the rejoinder.

*CHAPTER XXII*

*AN AERIAL DUEL*

"Message from the _Scorpion_, sir!" cried Keane, a little before midday, from the little key-board where he had been patiently waiting for the last hour.

"Good! What does the brigand say?" asked Tempest.

"Expects to be here within an hour."

"Then we haven't a moment to lose," replied the colonel. "At the same time, I am glad we have had this message, for to be forewarned is to be fore-armed."

Then, turning to Keane, whom he knew to be his best and most brilliant pilot, he said, "Where would you like to be stationed, boy?"

A sudden gleam came into the youth's eyes, for he saw that his chance had come.

"Let me have all the spare petrol from the other machine, and let me get up above the clouds in that new No. 7 Bristol Fighter which you brought over, sir."

"I'm afraid it means certain death for you, my lad," replied the chief, after a pause, unwilling to permit the youth to take such unknown risks, and yet still more unwilling to deny him his request. "This _Scorpion_, according to Captain Watson, must be some stunting machine."

"I am willing to take the risks, sir," replied Keane. "It is not my first fight with a Hun."

"Don't I know it, boy!" replied the other, gazing with fond admiration into the frank and pleasing face of the pilot. "The ribbons which you gained speak for themselves, but they don't tell half the story. Don't I remember the morning when you went over the line by yourself, and encountered seven enemy machines, how you fought with them for an hour and brought five of them down, chased the others till your machine threatened to break up, then turned and staggered home with your wings shot to ribbons?" and the colonel fondly patted the youth's shoulder.

"Then let me go, sir. The brigand will be not a little confounded to find himself attacked both from the ground and the air at the same time."

"You shall go!" said the colonel after another pause. "Will you take a gunner with you?"

"No, sir. I would rather go alone."

And while the petrol was drawn off from the other machine, No. 7 was brought out, filled up, and tested, ready to start at a moment's notice. The Vickers gun, fixed forward to fire through the propeller, was carefully examined, and several drums of the new armour-piercing bullets placed in position. Another moment was given to the alignment of the gun-sight, a matter of supreme importance in an aerial duel like this one promised to be, for the slightest error in this respect would be like courting disaster.

Ten minutes later the signal was given to stand clear, the colonel himself swung the propeller, and, instantly, the powerful 350 H.P. Rolls-Royce burst into life with a crackle and a roar, and, when the chocks were withdrawn, the Bristol dashed across the ground, leapt into the air at sixty yards, and by a steep climb just cleared the tops of the trees on the edge of the forest.

"What are his chances, Colonel?" asked Captain Hooper.

The chief shook his head as though doubtful of the result, then, after watching the machine for a moment, as it climbed in rapid spirals up into the clouds which half covered the sky at four thousand feet, he said:--

"There is no pilot aboard the _Scorpion_, or any other machine for that matter, who can hold a candle to Keane, but--it is the amazing speed and climbing powers of the other machine that I fear. Still, it will be some fight, and if we fail to trap the brigand down here, well, it is just possible, despite his disadvantages, that Keane may bring the rascal down. He'll have to keep well out of sight, though, and run at less than half-throttle behind that cloud bank till the moment comes to strike. And now to stations, all of you, and keep well out of sight. Professor Verne, I am afraid you will have to take charge of the two prisoners. Don't let them get away for heaven's sake. You must shoot them first."

"I'll take care of them, Colonel," replied the eminent man, "though it is a somewhat unusual occupation for me."

"Needs must when the devil drives, Professor! I told you it would be some desperate adventure. Have you had any luck with that evil genius, yet?"

"Not the slightest, so far. He is prejudiced against the English mind, and is secretly rejoicing over the expected arrival of the _Scorpion_."

"Tell him from me, Professor, that if he attempts to escape, I shall shoot both him and his accomplice without the slightest compunction," said the colonel, as he turned away to re-examine all his defensive posts, and to alter the position of one of the machine guns, which had been entrusted to Captain Sharpe.

Fifteen minutes passed away, and the Bristol, hidden away behind the cloud bank, kept its engine well-throttled down, lest the roar of the powerful motor should reveal its presence, when, suddenly, from one of the watchers, the cry arose:--

"Aeroplane approaching from the south-east."

"Is it the _Scorpion_, Captain Watson?" the colonel asked, as soon as the machine had been located.

"Yes, it is the same brigand, sir."

Then, with amazement bordering on the supernatural, the little garrison saw the _Scorpion_ moving across the sky at a miraculous speed, and making directly for the secret aerodrome. Once or twice it circled around at three thousand feet, then dived a clean two thousand five hundred upon its objective, silently, like a mysterious phantom bird. At five hundred feet it flattened out, rode gaily above the tree tops, then swooping like a falcon, once more touched the ground lightly, and came to rest within thirty yards of the secret hangar.

"Haende in die hohe!" cried Colonel Tempest, stepping out into the open, and confronting the visitors with a couple of revolvers, as they prepared to leap from the armoured conning-tower.

"Ach Himmel! We are betrayed!" cried Spitzer. "The _verdammt_ English have captured the aerodrome."

Without thought of surrender the brigands tumbled swiftly back into the armoured cell, just as a shower of bullets from both revolvers swept the upper surface of the cockpit.

"Fire!" shouted Tempest, stepping back, as the daring bandits, regardless of the danger, started the propellers once more by means of the self-starting knob, within the conning-tower.

And the next instant, even as the machine turned and raced for safety, a terrific hail of bullets from the two machine guns swept the _Scorpion_ from stem to stern. One of her machine guns was swept from its mountings, and it is believed that one at least of her crew was wounded, probably by the Colonel's revolver shots, but as for surrender, the pirates would have none of it, as, apparently unhurt in any vital spot, the _Scorpion_ recrossed the aerodrome, staggering once or twice under the fierce welter of bullets, managed to leave the ground, and sail over the tree tops out of immediate range.

"Confound it! She's absolutely bullet-proof!" shouted the colonel, who was furious at his failure, for his object had been to capture the machine and its crew wholesale, because of its valuable secrets.

"We shall see no more of her!" exclaimed Captain Hooper.

"Just wait a moment," said the skipper of the air-liner. "She'll have something to say presently. You don't know these infernal brigands."

The last speaker was right, for a moment later the infuriated Spitzer, sweeping round at a frightful speed, swooped down upon the little hangar, where he presumed the English were in possession, swept the place with a burst of machine gun fire from his remaining gun, then dropped a bomb filled with high explosive right into the middle of the structure; whilst he, himself, was screened by the trees from the enemy's fire.

The roar of the explosion was deafening, and several trees in the vicinity of the workshop were blown to fragments, whilst the workshop was now a tangled mass of wreckage. It was also burning furiously, and a thick pall of dense smoke already hung over the spot.

"The professor!--we must save him!" cried Tempest, who was already limping from a bomb splinter which had pierced his leg.

Captain Watson ran to help him, but the two machine gunners, Sharpe and Hooper, stuck to their posts ready for the next attack, which they knew would not be long delayed, for Spitzer, during his last circuit, had marked the position of the two machine gun posts.

As the rescuers hastened to the assistance of the prisoners, they came upon Professor Verne, bleeding from the hands and face, dragging the prostrate form of the German from amid the burning wreckage.

"Ah, you are wounded?" cried the colonel.

"It is nothing," replied the other. "See to the mechanic. I fear he is killed, poor fellow, by his own countrymen."

It was so; his mangled form was found buried under the _debris_ of the workshop. The German professor and his rescuer were both helped to safety; then the battle began again.

"Here comes the _Scorpion_!" shouted Captain Watson. "Look out there!" and instantly the air resounded with the sharp, short crackle of the air brigand's gun--

"Rep-r-r-r-r-r----!" as the raider swept the machine gun posts.

At this very instant, however, the sound of whistling wires came suddenly from overhead, as something swooped down from the dizzy heights upon the attacker. Then the sharp crackle of a Vickers gun rent the air, as, in a headlong dive of two thousand feet, the Bristol Fighter hurtled down, spitting fire through the whirling propeller, and driving its quarry almost to the ground by its unexpected onslaught.

By a miracle almost, the _Scorpion_ escaped a terrible crash, flattening out within two feet of the ground in the middle of the glade, then started its upward climb to out-manoeuvre its new opponent, for the rest of this terrific combat was confined to the air.