THE CASE OF THE FLYING SUBMARINE

Chapter One
The PXR1
The long, grey car swung out of Whitehall into the Admiralty yard. Out of it jumped the loose-limbed, broad-shouldered man whose name was famous throughout Europe as that of the most deadly man-hunter now living — Sexton Blake, detective.
Together with the youngster who had got out of the car with him — Tinker, Blake's assistant — the detective strode in through the high doorway. Five minutes later he and the youngster were in the private room of Sir Walter Thackery, one of the biggest men in British naval circles.
"I'm glad you've come. There's a queer business to be tackled. We're worried — don't know what we're up against."
In brief, jerky sentences, Sir Thackery talked while he stabbed with a pen at the pink blotting-paper on his desk.
"Want you to do a Government job, Mr Blake. May be risky, though, I warn you."
Sexton Blake gave a grim smile.
"I expect risks in my profession," he said.
For a moment the naval man smiled, too. Then his face went grave again. Clearly, he was strangely anxious.
"Good! But before I ask if you'll take it on I'd better explain a bit, eh? Have a cigarette?"
Blake declined the proffered cigarette. He always smoked a pipe when considering the various aspects of a new case. It helped to focus his mind. He took his curved briar from his pocket now and proceeded to fill it. Sir Walter Thackery, with a worried frown on his face, lit a cigarette.
"It's a naval secret at present," he said. "Strictly a secret. We're experimenting with a new type of submarine. We've built one on a small scale. If it's all right, we shall build more — the full size, though this first one is built for full service in every way at sea. At present she is down at Selport, on the outskirts of Portsmouth, in the Government dockyard there. The PXR1, Mr Blake. A very fine boat she is, too, though, of course practically a miniature one. Carries a picked crew." A gleam of enthusiasm, came into his eyes. "Very fine! The very latest thing. Other countries would give their ears to know all about it."
Blake nodded silently.
"I understand."
"Well, one country — we don't even know which — has found out something," continued Sir Thackery. "Something! We don't know how much. But we do know that there is going to be some attempt made upon the PXR1. That's certain!"
"To destroy it?" asked Blake. "Or to get the plans?"
The naval man leant back in his chair.
"We don't know," he said abruptly. "We know nothing beyond the bare fact that some sort of attempt is going to be made to do Britain down with regard to the PXR1. What form it will take — whether, as you suggest, it will be an attempt simply to blow her up to delay us, or in the hope that we can't build a similar one, or whether it will be the more useful scheme of collaring her outright as a model, I can't tell you, because no one knows — except the beggars responsible."
"That makes things a bit difficult," murmured Blake thoughtfully.
"It does," agreed the other, the worried frown back on his face. "Thundering difficult! But what we propose is this — that you are on board the PXR1 when she takes her trial trip out of Selport and down the Channel. We want an expert detective on board to watch for any eventualities. We want, too, a private man — a man who hasn't got fear of the Government hanging over him, with all its red tape, and so has a free hand."
Sir Walter Thackery leaned across his desk. "Will you?" he asked. "Will you take this thing on?"
Blake nodded.
"Certainly. I and my assistant here will be on board this submarine when she goes on her trial trip. When will the PXR1 be leaving Selport?"
"On the sixteenth — two days' time. This is an important business — we'll send someone down to the dockyard with you to make everything smooth for you." He rose and held out his hand. "Good luck!"

A cold wind, with rain in it, was cutting through the Government dockyard at Selport as four hunched figures went stumbling across a rusty railway-line close by the water.
"Go carefully, Mr Blake!" warned one of the figures, who was smoking a stump of cigar between tight-clenched teeth.
It was the captain of the PXR1 who had spoken.
Blake and Tinker had been dining ashore in Selport with the captain and one of the other officers. Now they were returning to the mystery-submarine. At six in the morning the PXR1 would slip from her moorings and creep out down-Channel for her tests.
As they made their way on, Tinker kept glancing around curiously. In the dim, flickering lamps the great sheds and the slippery wharves seemed strangely dreary and desolate. But Tinker was wondering what crouching figures might not be hiding in those inky shadows?
It would be a big thing for a foreign power to find out fully about the new type of British submarine — a wonder-submarine, the captain had called it enthusiastically to Blake. Small, but neat and powerful, capable of immense speed, and mounting very deadly guns of a new type specially designed for submarine work, the PXR1 type would be a new force in naval warfare, without a doubt.
And it was known that some foreign power had indeed learnt of the existence of this first model PXR1. It was known that an attempt of some kind was to be made to wrest the secrets of the new submarine from Britain! Thus, Tinker was thinking.
"There's one thing," Tinker told himself, "there'd not be much point in blowing her up. What's been built once could be built again. So I don't think we're likely to go to the bottom of the sea with her, anyway."
Which thought was rather a relief!
A sudden challenge rang out of the darkness. A marine, with a fixed bayonet, stepped forward sharply into the yellow light of a wall lamp.
"Halt! Who goes there?"
"Friend!" answered the captain of the PXR1, taking his cigar from his mouth.
"Advance, friend, to be recognised!"
They went forward again.
And so they passed through the ring of sentries, and came to the wharf where the most modern submarine in the world was moored. On to the steel deck, and down into the narrow, electric-lit interior.
Tinker drew a deep breath. For the moment he had almost forgotten the grim reason for their presence on board.
"Crumbs, guv'nor!" he whispered excitedly. "Think of it — to-morrow we shall be off in her, out in the Channel, buzzing along fathoms deep! My hat! I'm looking forward to it!"

Chapter Two
Vanished!
Eight fathoms, sir," grinned the burly sailor, in answer to Tinker's question. "Forty-eight feet, that is, under the bloomin' water."
"Never been so near Australia in my life!" chuckled Tinker humorously; and the sailor's grin widened.
"You'll be nearer yet, I'll lay, before we get back to Selport," he said. "This can go deep, this here craft can. She's a little wonder! And fast—well, you've seen that already for yourself."
They had been out over four hours now, sometimes on the surface, sometimes below. Tinker was enjoying himself immensely. He had woken up to find the PXR1 already well out from Selport, in a glittering sea. And now that he was getting his sea-legs, he almost felt that he'd been used to submarines all his life.
When they had last submerged, England had been a dim streak on the horizon. When they rose again they would probably not even be able to see that much of land — so Sexton Blake had suggested to the youngster. And when the PXR1 did rise to the surface, some time later, Tinker saw that Blake had been right.
Peering out through a tiny porthole, Tinker saw the tumbling grey sea stretching away endlessly in the sunlight. Away to the west a speck of black and a smudge against the sky showed where some tough old tramp-steamer was plunging homeward from some foreign port. Otherwise, the submarine seemed to have the whole ocean to itself. With Blake, Tinker scrambled out on to the narrow deck. The PXR1 was cutting through the steep waves in fine style, plunging her nose sheer through the curved, grey waves that seemed to rise to meet her. The salt spray came dashing into Tinker's face, and he breathed deep of the briny air, his eyes gleaming.
Blake, leaning on the thin rail, watched Tinker's face with a smile.
"Better than Blackpool, eh?" he chuckled.
"I should say so!" laughed Tinker. "This is the real sea life, this is!"
He began to whistle, "Oh, a sailor's life for me!"
Blake chuckled again, aud clapped the youngster on the shoulder.
"You'll have to leave me, and take to the Navy, I can see!"
Tinker stopped whistling.
"My hat, no!" he protested. "Much as I admire the Navy, I'd sooner be with you than anywhere, guv'nor." And then he saw by the detective's twinkling grey eyes that Blake had only been pulling his leg. "By the way," he added in a lower tone, "I'm afraid I've been enjoying things a bit too much, perhaps. I've not been keeping my eyes skinned, as I ought to. Have you noticed anything, guv'nor?"
Blake shook his head.
"Nothing at all," he murmured. "I've been pretty well all over this submarine, Tinker, and not a single suspicious thing has caught my notice."
"S'pose that old gent at the Admiralty was right in thinking there's going to be some funny business?" said Tinker doubtfully.
"Oh, I should say so!" answered the detective. "A man like that, wouldn't go off at the deep end unless he jolly well knew what he was talking about. But as far as I can see, these trials are going to be carried out without incident. So you just enjoy the experience, young 'un, and don't worry about business; not many people are privileged to enjoy a trip in a new British submarine!"
Tinker took the detective at his word, and enjoyed himself to the utmost. With his cheery disposition, he soon made great pals with the crew, and had the time his life. It was with a feeling of regret that he learnt, on turning in, that the PXR1 would turn her nose back for England soon after midnight.
But next day, on her way back, there was some trouble with the submarine's engines, though there was no suspicion that they had been tampered with.
"We sha'n't make Selport, I'm told," Blake remarked to Tinker after breakfast. "They will probably take her in to Gallows Cove; that's a lonely cove about ten miles from Selport. Being well sheltered by headlands, it is a very suitable place for lying-up in for a day or so, till they get the repairs effected."
And by midday, the PXR1 was riding at anchor in a lonely cove overhung with beetling crags.
"What about a spell ashore?" asked Tinker carelessly that afternoon. But Blake shook his head.
"No one is allowed to leave the submarine till we get back to Selport," he said. "Strict orders, for obvious reasons. I dare say we could get exemption, but I don't want to ask that."
"Oh, rather not!" cried Tinker. "I was only wondering, guv'nor!"
But it seemed that Tinker's were not the only thoughts that had turned shorewards. For when dusk was setting in — so it was discovered a little later — one of the sailors had quietly slipped overboard and swum for the rocks.
If one of the men had been found with a bomb in his possession, there could not have been more trouble. The fur flew with a vengeance on board the PXR1! The wireless was in touch with the Naval authorities and the police in no time. And Blake's face wore a very thoughtful frown.
"I don't know what it means, Tinker," he said to the youngster, grim-faced. "But I'm uncommonly concerned about it! It looks fishy; more than an ordinary case of desertion. And the man got away under our very noses! Can't think he could be a regular British tar. Whatever happens, we mustn't let the Admiralty down; they're pinning their faith to us! I'm off ashore after all, to get on the track of the deserter if I can. You must stay here and watch!"
Sexton Blake was rowed swiftly ashore, Tinker watching from the deck of the anchored submarine. The detective was landed on the shingle at the foot of the cliffs, alone, and the boat returned to the PXR1.
The detective ranged along the cove with an electric flash-lamp, and it did not take his expert eyes long to pick up the trail he sought.
Over the shingle, up a muddy cliff-path into the fields above, Blake followed the trail of the deserter.
The village of Compton, half a mile from the cliffs, was in darkness when the tall figure of Blake came dropping down a rutted lane to the village green. It had been raining that day, and the footmarks of the deserter were fairly easy to follow for a skilful tracker.
And in the village Blake made one or two curious discoveries.
A man in sailor's uniform, soaked to the skin, had hurried into the little post-office and sent off a long and strangely-worded telegram to Dover. He had then, without explanation, purchased some dry clothes from an old farmer down the road, and set off at a rapid pace along the Falmouth road. And down the road into the darkness he had vanished!
Blake, too, took the Falmouth road.
Some time after midnight, he returned through Compton, seated beside the driver of a commercial van that was passing that way in order to pick up the coast-road. His face was oddly grim.
For far back down the Falmouth road he had found the dead body of the mysterious sailor, who had been knocked down and killed by some chance motorist. His mind concentrated on escape, he had probably not paid sufficient heed to the perils of the road.
It was one o'clock when Sexton Blake, once more on foot, topped the cliffs overlooking Gallows Cove. He made for the top of the cliff-path, then stopped short.
"Good Lord!" muttered Blake in bewilderment.
He had expected to see the lean, dark shape of the PXR1 riding at anchor in the cove below. But the PXR1 had vanished.
"What the dickens!" gasped Blake. "She's gone! But hang it, her engines were out of order!"
It was weird, incredible! But all the same, there was no doubt about it. The mystery-submarine had vanished utterly, whatever the reason could be. And, as he stared down at the sea, Blake felt a startling presentiment of disaster!

Chapter Three
The Goggles Clue
"Well," Blake told himself, "there's a chance it may be all right, I suppose. But I fancy it's all wrong! The sooner I get in touch with Selport the better!"
His face was drawn and anxious as he hurried back to the village.
It took time to awaken the postmistress, but at last he was in telephone-communication with the Naval authorities at Selport. No instructions for the PXR1 to leave Gallows Cove had been wirelessed to the submarine, Blake learnt. The news of her disappearance was evidently a bombshell to the Naval authorities there.
With tight lips, Blake hung up the receiver.
What had happened to the PXR1? The question tormented him.
Back he went to the cliffs. The moon had risen, and by the light of it, and with the aid of his electric torch, he scoured the cove and the cliff above. It was up on the cliffs that he made his great discovery!
A pair of metal-rimmed goggles, deeply embedded in the turf! To Blake's keen brain, piecing everything together, they were the one clue he wanted.
"So that's the solution to the riddle of the vanished submarine!" he muttered hoarsely. "It seems almost incredible, and yet it's the only possible theory! But there's no time to lose — I must get back to Selport!"
It was while he was driving fast out of the village in the rattling old car that was all he could find to hire from there, that Blake put to himself a disquieting question.
"Shall I ever be able to persuade them of it?" he muttered. "It sounds so wild, so absurd! Will they ever believe me?"
And at the hastily called conference of Naval men in Selport, turned out of their beds before dawn to discuss the problem of the PXR1's disappearance, Blake soon found that his doubts were well justified.
"No good springing the theory on them. I shall have to work up to it, I suppose," he told himself as he listened impatiently to various conflicting opinions from the men present.
One old admiral brought his fist crashing down on the table.
"They've sunk her!" he snorted. "Whoever they are, these spies who have got at her, they've sunk her! That's clear as daylight! What else can have happened?"
"But it has been ascertained that she did not sink in Gallows Cove, where she was anchored," objected a younger man.
"I don't care about that. They've sunk her," repeated the first man obstinately.
Blake broke in quietly.
"I think not," he said. "For one thing, how could they have lured her out to sea before sinking her, as they would have had to do, since she's not gone down in the cove? But the idea of their wishing to sink the submarine is not good enough for a moment, in my opinion. Where would be the point? No foreign power could hope for a moment that we should not be able to build an exact replica of the original submarine. A sheer waste of time to sink the PXR1."
"Then what's happened to it?" growled the old admiral.
For answer, Blake took from his pocket the pair of heavy metal-rimmed goggles and tossed them on to the table.
"There, gentlemen, is the answer to the whole question," he said, with grim coolness. "I found this clue on the cliffs above Gallows Cove, embedded deeply in the turf — strangely deep."
The naval men stared at him in amazement, then glanced at one another. Blake nodded.
"I mean it! It's all clear enough. The PXR1 has been stolen!"
"But how on earth could anyone steal a submarine?" rasped someone.
"Preposterous!" snorted the old admiral. "With all the men on board, too!"
Again Blake nodded.
"It sounds a stiff proposition, I know," he said. "But there's no time to lose. I must explain quickly. But I know that unless I do explain, and fully, not one of you would admit my theory for a moment, which is why I must waste valuable time going over it before I ask for the loan of a seaplane!"
There was a ring almost of bitterness in his voice. Knowing all that he did, it galled Blake to have to waste time in explanations. But it was unavoidable, as his own plane was housed in an aerodrome north of London — too far away to get to quickly.
"Look here," he said swiftly, "it is perfectly obvious, for reasons that I have already stated, that the submarine has not been destroyed. But we know that unless the captain got his repairs done in record time, and then went mad into the bargain, after having smashed the wireless transmitting apparatus, that the PXR1 did not leave Gallows Cove of her own free will. On the other hand, if the submarine had been attacked by a strong armed force, no British crew would submit easily! There would have been the dickens of a fight, and something of it must have been heard if it had taken place. We can wash that idea out."
"Seems to me, Mr Blake, that you are washing out all possible solutions to the mystery!" broke in a Naval officer.
"Not at all! I tell you that the PXR1 has been stolen," went on Blake. "And I can tell you, too, who has stolen her: Carlovia!"
"Carlovia!" gasped someone. "They don't like us, I know."
"And I'm afraid that's partly my fault," admitted Blake.
"Ah yes," muttered the officer, "Weren't you involved in some sort of revolution there?"
"I helped to restore the rightful heir to the throne earlier this year," explained Blake, "but two months ago the rebels regrouped and assassinated him. Regrettably, they are now in control and there's little we can do about it, short of declaring war!"
The old admiral brought his fist crashing on to the table again.
"Do you solemnly mean to tell me, Mr Blake, that you can possibly deduce all this from that pair of goggles?" He snorted.
"Yes," retorted the detective. "But, as a matter of fact, I had guessed the truth before I found them, although I did not then suspect Carlovia; for there was no other way of solving the riddle. I told you that the goggles were embedded deep in the turf on the cliffs. Deep, gentlemen! But they are not in the least rusted. They had not been there long. How was it that they had driven themselves so deeply in? Obvious, they had been dropped from a very great height."
"What of that?" came a query.
Blake laughed dryly.
"What of that, you ask? Out on the open cliff? Don't you see, the problem is, from what were they dropped which was at a great height above the open cliff? Only one answer — an air vessel of some kind."
The old admiral leaned back in his chair, his face bewildered.
"I don't see what you are driving at, Mr Blake," he complained.
"An airship," explained Blake, "had already occurred to me as being the only possible solution to the mystery. The air! Since the PXR1 did not sink, nor put out to sea, as we've already realised to be impossible, the only way left for her to leave her anchorage was by air, gentlemen! Yes, the air! She was carried off by air!"
There was a tense silence in the room.
"You're not serious?" rapped out one of the Naval men.
"Perfectly," answered Blake, a note of impatience in his voice. "And I want a seaplane in which to follow."
"But your theory is too wild for words, my dear sir!" gasped the old admiral. "You're wrong! Perhaps, though, an enemy ship towed her away!"
But Sexton Blake shook his head.
"No! The PXR1 would have put up a stiff fight under those circumstances. They've got guns, remember — splendid guns. The fight would have aroused the village. I tell you that the airship is the only way. They couldn't use their guns on that — at least, to serious purpose if she were dead above them."
He clenched his hands.
"Can't I persuade you that this is the truth of it?" he exclaimed desperately. "Every minute we are losing precious time."
"Anyway, why should you fix it on Carlovia ?" asked the admiral obstinately.
"Obviously," explained Blake, "since these goggles are marked as being manufactured in that country. They are Carlovian without a doubt. That is evidence enough! And think of the great lakes in western Carlovia! Their plan, doubtless, is to lower the PXR1 into one of them, get rid of the crew — I know from personal experience how unscrupulous the rebel leaders are — and then examine their prize and discover its secrets!"
He stared round at the ring of faces and read in them the bewilderment and doubt that he had known he would have to face. He leaned forward with gleaming eyes, hands gripping the edge of the table.
"My heavens, but I've got to convince you! I tell you I'm right — it's not impossible. The PXR1 is not one of these big submarines they've been building, but a small craft, the model of the kind to be made, specially for quick manoeuvring. Lightly built! They could do it, if they once got their grappling-hooks on her! Imagine a great modern airship the size of a German Zeppelin, or even bigger — "
He broke off. For some moments there was dead silence in the room. Then suddenly one of the younger Naval men sprang to his feet.
"By thunder, he's right!" he cried. "Trust Mr Blake not to let us down with a fairy story! His idea of it is right! I'm sure of it!"
Blake smiled. He had won through!
Less than twenty minutes later, a British seaplane went swooping up from the water outside Selport harbour.
Sexton Blake, pinning all to his amazing theory, was going in pursuit of the vanished submarine!

Chapter Four
The Hawk Strikes!
To return to the PXR1 from the time Sexton Blake left her. Tinker had watched the detective being taken ashore, and then had gone below and turned in. He was tired, and it did not take the youngster long to fall asleep. He awoke suddenly.
"Hallo, what's happening?" he muttered. There was an odd motion to the submarine. "Not going off to sea again in the middle of the night, are we?" he asked himself in puzzled surprise.
He raised himself in the narrow bunk and peered out through the tiny porthole. But it was too dark to see anything outside.
The gentle swaying motion continued, strangely bewildering.
It was unlike the ordinary sea-roll that he had already experienced. This was a different thing.
"P'r'aps it's getting up rough," Tinker told himself rather drowsily, but still puzzled. "Biding at anchor in rough weather may feel like this in a small vessel like the PXR1. Can't hear any waves, though."
He listened. Though he could not hear the sea, he made out another sound. It was a low humming, like a swarm of bees.
"What the dickens!" muttered Tinker. A vague disquiet had gripped him suddenly, from intuition rather than reasoning. He heard sudden hurrying feet pass outside the door of the tiny cabin. The whole submarine crew seemed to be rousing up. A shout, wild and hoarse, reached him. The PXR1 seemed to lurch sickeningly, then sway steadily. Another muffled shout, with a high note of wild alarm. Tinker, thoroughly wide-awake, tumbled out of his bunk. Past the door of the cabin a rush of heavy feet. Shouts, and a sudden cry.
The youngster, now really alarmed, had snatched up his trousers to pull them on over his pyjamas. But now he dropped them to the floor, and sprang for the door of the cabin in his night clothes. He dragged it open and darted out — to be almost knocked head-over-heels by a sailor who came tearing by half dressed.
Down the narrow alleyway the man rushed and disappeared at the farther end. Tinker, getting back his breath, broke into a run, too.
A wild confusion — shouts and running feet. For a moment there flashed into Tinker's mind the picture of a wasps' nest when disturbed. And the similarity was made more complete by that low hum that seemed to fill the air all around him.
Half a minute later the boy stumbled up on deck. An icy wind went streaming past him. As he came out into the open air the vibrant drone that had so puzzled him came yet louder to his ears. He stared around — saw the dark shapes of men clutching at the rail, shouting. He glanced down to where he thought to see water washing up the steel sides of the submarine, but there was no water there. Tinker rubbed his eyes.
"Where's the sea?" the youngster muttered, half stupidly.
The sea had vanished!
And then he saw it, and a choking cry stuck in his throat. He wondered if his brain had given way. For the sea lay placid far away below! He glimpsed the black line of the coast winding away, a ragged streak, far beneath! To the north, the twinkling street-lamps of some distant town, dropping behind as the PXR1 rushed on through the air, high up above the earth and sea.
Tinker clutched the rail desperately and shut his eyes. When he opened them again he thought to see the vision changed. It must be a dream — all a dream!
But when he opened his eyes again the sea still lay stretched far beneath, the distant lights still twinkled up to him. He felt the deck sway slightly beneath his feet. Vaguely, the shouting and the confusion came to his ears, and with it all that strange hum, like innumerable bees.
It was above him. He realised that suddenly. He stared up, and again a cry broke from him. In a moment he had realised the nightmare truth!
For, above him, the vast, dim shape of a mighty airship could be seen black against the stars. Four steel cables streamed down from it, and these were attached by grappling-hooks to the deck of the PXR1. The drone of the airship it was that he had heard — and the submarine was slung beneath it, was being carried off through the upper air, and the men on board were helpless, had no power to resist!
Someone went scrambling past him, yelling. He heard something about guns.
The idea swept into the youngster's mind — guns! But then he realised that guns were useless. Even if the guns of the PXR1 could be brought to bear on the huge gasbag above, the submarine must perish with the airship if that were wrecked.
Wireless?
And then Tinker saw that the wireless aerial had been smashed utterly.
A sailor was lying on the deck, someone supporting his head. He was talking wildly. Tinker heard the words, snatches of tumbled sentences, half inarticulate.
"Hit me on the head — knocked me out! The cur! But I saw — six of them — rowed out to us! I saw the airship, too! Up above! Grappled on to us; see how they've done it — if it ain't a dream — "
The man was one of the watch that had been knocked out. His last words were oddly shrill.
So six men had rowed out under cover of dark to the anchored submarine and knocked out the watch! It had been cleverly done. And those six had taken care to wreck the wireless!
Like madmen they were, those British sailors. Tinker saw one man shake his fist on high, almost sobbing, raging, helpless. "If it ain't a dream!" That was it. It must be all a dream.
Tinker glimpsed the face of the captain. It was white as paper, dazed. The officer, brave as a lion, felt disgraced, humiliated. He felt he had let his country down.
So that foreign power, whichever it was, had planned this. This! Who could have dreamed of this?
From Tinker there broke a wild laugh.
"The flying submarine!" he chuckled mirthlessly. "But where are we off to? Anyway, I guess England will never know!"
England! Far away below, those blurred, winking lights were dropping from sight. Up above, the maddening drone. It was all so wildly ridiculous. It simply couldn't be!
But in his heart Tinker knew that it was not merely the nightmare it seemed. It was grim truth!
"Kidnapped!" he laughed wildly. "Kidnapping a submarine! Plans aren't good enough for them; they know that certain things aren't put on plans. So they're collaring the very submarine itself! And us — we shall have to be put out of the way!"
His heart seemed to miss a beat at the thought.
It would mean war with Britain, if Britain ever found out. But how could Britain learn the truth if those on board the stolen submarine never returned home?
Tinker licked dry lips. He was shivering with cold, but he did not know it. On through the icy air the submarine went skimming, caught up beneath the droning airship like a mouse in the talons of a hawk.
"Crumbs, I never heard of a submarine that sank upwards before!" Tinker murmured, trying to cheer himself, but failing to succeed.

Chapter Five
The Struggle in the Clouds
A grey light in the east proclaimed the coming dawn, as Sexton Blake, in his seaplane, rose from the water outside Selport harbour, on the trail of the PXR1.
With the one idea of speed before him, Blake had declined the offer of a pilot. Besides, waiting for a pilot would have meant still more delay. Accordingly, he had chosen a small but powerful single-seater seaplane, which had the additional advantage of being ready to hand.
Expert pilot as he was, Sexton Blake felt quite at home with his hands on the controls of the speeding 'plane as it climbed like a bird into the misty sky.
He brought the machine round in a sweeping curve, and soared away down-Channel.
He was travelling at terrific speed, whereas he knew that the airship bearing the stolen submarine would only be capable of travelling comparatively slowly, burdened as it was.
"I ought to overhaul them before they cross the Carlovian border," he told himself with grim satisfaction.
"Jove, but this is a fast little bus if ever there was one!"
Gradually the sky grew lighter as he skimmed on through the clouds.
He began to have doubts as to whether, after all, he was going to succeed in overtaking his quarry in time. For if he ventured inside Carlovian border, he could never hope to accomplish his design.
And then at last, in the grey dawn light, he saw ahead of him that which he sought!
A strange enough sight it was, and he drew a quick breath as he peered ahead. Although he had expected it, it came almost as a shock to see, in actual fact, the PXR1 and its captor in mid-air.
"My word, I don't wonder those chaps at Selport weren't ready to believe me!" he told himself with a sudden chuckle. "The flying submarine! What a stunt! These Carlovians certainly are cool customers!"
He swooped down to a lower level. To his intense satisfaction he saw, as he drew nearer, that the great airship was flying very low as it approached a wide river which flowed to the sea from the great lakes on the western edge of Carlovia's border.
"She can't get very high with that great thing slung underneath," he told himself. "Good! That's what I want!"
He was overhauling the airship rapidly. Bigger and bigger it loomed, till he could even see the thin threads of the cables by which the submarine was grappled. Then Blake drew a sharp breath.
Away in the dim distance he had made out the hazy, glimmering sparkle of one of the lakes. The airship had almost reached its home country! If it got there before he could overhaul it, he could not save the PXR1!
"And what's more, it'll mean war if I fail!" he told himself with a worried frown. "But if I can save the submarine, the affair can be hushed up, with luck. Britain isn't afraid of Carlovia — not by long chalks! But war is always a thing to avoid at all costs."
But he realised a few moments later that he had no need for doubt. He was overtaking the airship far too swiftly for it to have any hope of getting over the border before he came up with it.
In a few minutes Blake was circling over the great air-vessel, watching, waiting.
Whether the Carlovians on board suspected his design, he did not know. The airship kept on steadily, now following the course of the river.
The seaplane was not a bombing machine, and was not fitted with the necessary apparatus for that purpose. But Blake had provided himself with a case of hand-grenades, and he held one in his hand now.
But he did not throw it, though the glistening envelope of the airship was close beneath him. Rapidly, coolly, Blake was making mental calculations. Could the submarine stand the shock of the fall into the river below?
Yes!
That was the answer he arrived at. At once he leaned over sideways in his seat and flung the grenade downward at the sleek back of the mighty air-vessel.
He did not have to throw another!
A tiny spurt of crimson appeared suddenly where the grenade had struck. In a moment it went licking along the shining silk, higher, bigger, till one end of the airship was a mass of quivering fire!
Soon the burning airship was dropping down to the river. There came a mighty, stupendous splash as the PXR1 took the water, rocked and almost turned turtle, then steadied and floated as if she had never been out of her natural element. Blake had calculated correctly. And the flaming mass that had once been a Carlovian airship drifted away to one side on the wind and came to rest on the water, too, still blazing.
Blake shuddered as he stared down.
"They asked for it, anyway!" he muttered to himself.
Then he turned to the controls, and brought the seaplane swooping down, bringing her gently to rest within a few yards of the PXR1.

Thanks to Blake's promptness, war was averted, for the whole affair was wisely hushed up by the British Government.
Since Carlovia had failed in her attempt, this country could well afford to let the matter stay as it was, and so avoid the terrible bloodshed of a great war. But had Carlovia succeeded in getting away with the PXR1, it would have been a different matter. Britain's honour would have been at stake, and war would have been inevitable, since Blake had been able to inform the Government that Carlovia was the country responsible for the loss of the submarine, and had been able to reinforce his reports from earlier in the year concerning the evil character of the rebels who currently held power in that desperate country.
As Blake said to Tinker later, when the two were back in their Baker Street house, the averting of another European war was perhaps the biggest thing he had ever done.
Just then, Pedro put his head on Tinker's knees, and the youngster, stretching out his hand, took a biscuit from a dish at his side. This he offered to the great bloodhound, but the dog only sniffed at it, then walked away.
Blake chuckled.
"It's a case of no work no pay with the old fellow, Tinker," he said. "Pedro resents the fact that he was not in the case of the flying submarine."
Tinker chuckled, too.
"But there's one thing that still puzzles me, guv'nor," he said. "Why did that sailor desert at Gallows Cove?"
"In order to send off a coded telegram to his friends, who by wireless instructed the Carlovian airship where to find the PXR1, Tinker."
Blake's face went grim. "A spy. His papers were forged. Got in, apparently, on the strength of being an engineering expert. He was that, and an expert spy."
"Well, I'm not sorry for him — specially when I remember how badly I got the wind up when I found myself up in the giddy clouds!" exclaimed Tinker with a sudden grin.
"That's one thing Carlovia can boast of, anyway; that they put the wind up you, of all people!" laughed Blake.