THE RIVAL SUBMARINES


* A Distributed Proofreaders US Ebook *

This ebook is made available at no cost and with very few restrictions. These restrictions apply only if (1) you make a change in the ebook (other than alteration for different display devices), or (2) you are making commercial use of the ebook. If either of these conditions applies, please check with an FP administrator before proceeding.

This work is in the Canadian public domain, but may be under copyright in some countries. If you live outside Canada, check your country's copyright laws. If the book is under copyright in your country, do not download or redistribute this file.

Title: The Rival Submarines
Author: Westerman, Percy Francis
Date of first publication: 1913
Date first posted:
Date last updated: July 4, 2018
Faded Page ebook#20180710





Produced by Al Haines.

Cover
Cover
"LIKE AN ARROW THE SNAKE-LIKE MONSTER DARTED FORWARD!"  p. 175.
"LIKE AN ARROW THE SNAKE-LIKE MONSTER DARTED FORWARD!" p. 175.

THE RIVAL SUBMARINES

BY
PERCY F. WESTERMAN

AUTHOR OF "A LAD OF GRIT"
ETC. ETC.

ILLUSTRATED BY
C. FLEMING WILLIAMS

THIRD IMPRESSION

LONDON
S. W. PARTRIDGE & CO., LTD.
OLD BAILEY

CONTENTS.

CHAPTER

  1. Captain Restronguet leaves Cards

  2. Sub-Lieutenant Hythe Discovers the Submarine

  3. The Man Who Walked out of the Sea

  4. The Signal from the Depths

  5. Captured

  6. Face to Face

  7. In the Conning-Tower

  8. Explanations

  9. The First Day in the "Aphrodite"

  10. The Second Officer Returns

  11. Concerning Captain Restronguet's Rival

  12. The "Vorwartz" is Sighted

  13. The Missing Submarine

  14. "La Flamme"

  15. A Visit to Gibraltar

  16. Over a Volcano

  17. The Rescued Italians

  18. The Rivals pass through the Suez Canal

  19. Struck by Lightning

  20. Rammed Amidships

  21. Captain Restronguet learns the News

  22. Beset by Somalis

  23. Over the Bar

  24. The Aero-Hydroplane

  25. The Approach of the "Vorwartz"

  26. The Sinking of the "Topaze"

  27. A Pilot under Compulsion

  28. In the Ballast Tank

  29. The "Pride of Rhodesia"

  30. Captured.

  31. The Unsuccessful Competitors

  32. The Fate of von Harburg

  33. Hythe's Masterstroke

THE RIVAL SUBMARINES.

CHAPTER I.

CAPTAIN RESTRONGUET LEAVES CARDS.

The garrison port of Portsmouth was mobilized. Not for the "real thing," be it understood, but for the quarterly practice laid down in the joint Naval and Military Regulations of 1917.

Everything, thanks to a rigid administration, had hitherto proceeded with the regularity of clockwork; the Army officials were patting themselves on the back, the Naval authorities were shaking hands with themselves, and, in order to cement the bond of unity, each of the two Services congratulated the other.

To the best of their belief they had reason to assert that Portsmouth was once more impregnable. A series of surprise torpedo-boat attacks upon the fortress had signally failed. The final test during the mobilization was to be in the form of a combined attack upon the defences by the battleships then lying at Spithead and the airships and aeroplanes stationed at Dover, Chatham, and Sheerness.

At eight o'clock on the morning of the day for the grand attack the fleet at Spithead prepared to get under way. Forty sinister-looking destroyers slipped out of harbour in double column line ahead, and as soon as they had passed the Nab Lightship a general signal was communicated by wireless for the battleships to weigh and proceed.

The Commander-in-Chief and the Admiral-Superintendent of Portsmouth Dockyard had breakfasted ashore on that particular morning, and both officers, with the Military Lieutenant-Governor of the Garrison, were to proceed to Spithead on a cruiser to witness the departure of the fleet. It was a fine day, but the beauties of the morning were lost upon them; to have to breakfast at an unearthly hour had considerably ruffled their tempers.

"Come along, Maynebrace," exclaimed the Commander-in-Chief irritably. "It's six bells already."

"Coxswain! Coxswain! Where in the name of thunder is my coxswain?" shouted Rear-Admiral Maynebrace.

"Here, sir!" exclaimed that worthy, saluting.

"Has the Lieutenant-Governor arrived yet, coxswain?"

"Yes, sir. The police at the Main Gate have just telephoned through to say that Sir John Ambrose has arrived, sir, but being rather late proceeded straight to the jetty."

"And kept us kicking our heels here," grumbled Sir Peter Garboard, the Commander-in-Chief. "Look alive, Maynebrace, or----"

At that moment a flag-lieutenant, red in the face and well-nigh breathless with running, dashed up the steps of the portico of the Admiralty House.

"Sir!" he exclaimed. "Sir, this message has just come through."

Sir Peter took the proffered envelope, fumbled with the flap with his flabby fingers, and at last untied the Gordian knot by tearing off one edge.

"Good heavens, Maynebrace!" he gasped. "Read this!"

The Admiral-Superintendent, with unbecoming haste, grasped the paper and read:--

"Vice-Admiral, First Battle Squadron, Home Fleet, to Commander-in-Chief, Portsmouth. On fleet weighing anchor a painted board was found attached to the anchor of every battleship, the said board bearing the words 'With the compliments of Captain Restronguet.' Have ordered fleet to anchor again and am sending divers to investigate. Will communicate their report in due course."

All traces of irritability vanished from the faces of the two Admirals. Instinctively they realized that something of moment had taken place, and that instant action was necessary.

"A diver has been playing the fool, perhaps?" hazarded Maynebrace.

"Diver? Humph! Can you imagine a diver leaving his card, in the shape of a painted piece of wood, attached to the anchors of forty ships? No, no, Maynebrace, it's not that: at least, that's my opinion."

"Well, then, sir, what is it?" questioned the Rear-Admiral.

"A menace to our fleet, that's what it is. Although there is no real harm done the moral result is bad enough. It's my opinion that there's a foreign submarine at work. Moreover, she must have means of direct outside communication while she is submerged."

"What makes you think it is a foreign submarine?"

"Logic, my dear Maynebrace, logic. None of ours are capable of such a feat, and there's no knowing what these foreigners are up to. As inventors they are miles ahead of us. And what is more, the name--Restronguet--doesn't that sound French?"

"Perhaps," admitted the Rear-Admiral. "But all the same it is exasperating; it is humiliating. And there are some who think that the days of the submarine are over!"

Even as the introduction of ironclads propelled by steam machinery had revolutionized naval warfare in the middle of the nineteenth century, so had the vast strides in military aeronautics rendered obsolete, or nearly so, the huge battleships that were the chief features of the world's navies in the beginning of the present century. For several years a fierce war of controversy was waged between the supporters of an all-powerful navy and those who pinned their faith in vessels capable of supporting themselves in the air and able to use the terribly aggressive means that the researches of science could bestow.

Not only did the Great Powers take up the question. The lesser states of the world, realizing that a sudden revolution in warfare might place them on an equal basis with nations who had hitherto kept them in the background, took the liveliest interest in the discussion. They agreed that since the ill-advised building of the first British Dreadnought had given other Sea Powers a chance to build equally formidable vessels at the same rate of construction, and that in consequence the predominant Navy flying the White Ensign was practically out-of-date, a drastic and sudden revolution whereby a comparatively cheap means of offence could be created might also render obsolete the huge costly leviathans that even the richest nations could ill-afford to maintain in the race for naval supremacy.

In Great Britain the opinion of those qualified to judge was nearly equally divided. The Blue Water School maintained that a numerically superior fleet of ships, capable of defence against aircraft, would meet the case, provided a supplementary division of airships and aeroplanes was ready to act in conjunction with the squadron. Battleships could keep the sea in all weathers, while aircraft were at the mercy of every hurricane.

On the other hand the supporters of the air fleet deprecated the need of a huge navy--using the word navy in the strict sense of the term. All the warships that Great Britain had at her command could not prevent the passage by night of airships and aeroplanes--either singly or collectively--across the comparatively short distance between the Continent and the East Coast of England, while by a judicious study of the barometer and climatic conditions generally the dangers of being overtaken by a heavy gale could be reduced to a minimum. Besides, had there not been instances of foreign aircraft manoeuvring over the East Coast naval ports at night during the progress of a terrible equinoctial gale that had caused, amongst other disasters at sea, the loss of several destroyers taking a doubtful shelter in the badly-protected Admiralty Harbour at Dover?

Up to the present time the result of the controversy in Great Britain was a compromise. Instead of spending a couple of million pounds upon a single battleship of between forty or fifty thousand tons, smaller ships were laid down and completed within eleven months. They were not pleasing to the eye. Even the "ironclads," ugly in comparison with the stately "wooden walls" of the early nineteenth century, were models of symmetry and grace beside the latest creations from the brain of the Chief Constructor of the Navy.

The modern battleships were vessels of but ten thousand tons displacement, or about the same as the "Anson" class of 1886. Their draught was, however, considerably less, being but twenty-two feet when fully manned and ready for sea. They were propelled by internal combustion heavy oil engines capable of developing 22,000 horse-power, the maximum speed being forty-two knots. The principal armament consisted of twenty-four six-inch guns, that for muzzle velocity, range, penetration, and bursting power of the projectile were more than equal to the fifteen-inch gun mounted on the later Super-Dreadnoughts of the United States Navy. The weight saved in engines, armament, and especially by the absence of coal, was devoted to additional armour. The battleships were veritable steel-clad vessels, for not only were the sides completely encased in Harveyized steel, but the upper decks were surmounted by a V-shaped roof capable of resisting the most powerfully-charged shell that airships could possibly carry.

Nor was the protection for submarine attack left unprovided for. The whole of the under-water surface was armour-plated, not merely by one skin but by two complete layers of steel, the thickest being on the inside. In the double bottoms thus formed, oil, the food for the motors, was stored. A powerful torpedo might fracture the outer armoured skin and release the oil in that particular section, but having the thickest plating inside it was considered almost a matter of impossibility for the latter to be holed and thus admit the burning oil--a source of danger that had long been recognized--into the vitals of the ship.

Submarine warfare, in the opinion of many naval experts, had had its day. At the height of five hundred feet a scouting aeroplane could easily detect the presence of a submarine so long as it was daylight. By night a submarine would be fairly safe from observation, but conversely her commander could not with certainty attack a hostile ship that had taken the precaution of manoeuvring with screened lights. In addition to the danger of mistaking friend for foe there was also the possibility, nay probability, of being unable to see the enemy's ship. It was, however, admitted that the submarine's chance was to attack either at dawn or sunset, with a fairly choppy sea running, and no aircraft to upset the calculations of the officer at the periscope.

Nor had the vast changes occasioned by the development of aircraft been confined to naval affairs. Fortifications, hitherto considered impregnable, were rendered untenable by reason of the danger from attack from above; and in this respect the reorganization of the Portsmouth defences might be taken as an example of what had to be done in other naval and military towns of the British Isles.

As is well known Portsmouth, the principal naval arsenal of the British Empire, is defended by a triple line of fortifications; while to prevent subsidized tramp steamers from emulating Togo's feat at Port Arthur by being sunk at the entrance to the harbour a line of massive concrete blocks were placed from the shore to the east of Southsea Castle, extending seawards as far as to Horse Sand Fort--one of the three built upon the bottom of the sea. This form of defence was severely criticized, for it proved a source of danger to trading and other private ships, while at high tide a torpedo-boat could with impunity pass over the submerged artificial reef.

Consequently a permanent breakwater, fashioned after the manner of that superb work protecting Plymouth Sound, took the place of the worse than useless concrete blocks; a similar one was constructed from Ryde Sands to the Noman Fort, and thus, with the exception of the main channel between these two hitherto sea-girt forts, Spithead was rendered almost immune from torpedo-boat attacks.

These breakwaters, and indeed all the fortifications on shore, were armed with the latest type of air-craft repelling armament; a three-inch automatic gun, capable of firing one shell per second. The bursting charge of each shell was proved to have an effective radius of a hundred yards, while the creation of air-waves and "pockets" resulting from the detonation, would seriously imperil the stability of every aeroplane within three hundred yards. At night each of these guns was supplied by an ingeniously constructed searchlight that, projecting a narrow ray of light almost parallel with the axis of the gun-barrel, rendered a "miss" an impossibility unless the range was greatly miscalculated. As the sights of the weapon were altered the beam of the searchlight was automatically adjusted. All the gunlayer had to do was to train the searchlight upon the hostile aircraft and fire.

Yet in spite of all these elaborate means of defence the main portion of the British Navy, seemingly anchored in perfect security at Spithead, had received a most unpleasant moral blow. Who and what is this mysterious Captain Restronguet?

CHAPTER II.

SUB-LIEUTENANT HYTHE DISCOVERS THE SUBMARINE.

"Pipe away the diving-party!"

H.M.S. "Ramillies," the flagship of the First Battle Squadron of the Home Fleet, had just anchored in almost the identical position that she had occupied barely a quarter of an hour previously. With mathematical precision the other battleships of the squadron had also returned to their late anchorage and were preparing to investigate the mysterious occurrence in the shape of a complimentary message from the still more mysterious Captain Restronguet.

Up from below tumbled the diving-party. Air-pipes, life-lines, pumps, dresses, and helmets were produced from some remote yet properly apportioned part of the ship and were thrown down in a seemingly chaotic manner upon the steel deck. Actuated by electric power several sections of the armoured shields between the upper deck and the eaves of the V-shaped shell-proof roof were lowered till they lay flat upon the deck, and steel ladders for the divers' use were rapidly placed in position.

"Do you wish me to go down, sir?" asked a sub-lieutenant of the Number One.

"Certainly, Mr. Hythe," replied the first lieutenant. "Make a careful examination for a radius of say fifty yards from the shot-rope. You will doubtless be able to see the place where the flukes of our anchor held before. Ascertain if there are any traces of independent work; such as footprints in the ooze, tracks of the underbody of a submarine settling on the bottom, for example."

"Very good, sir," replied the sub, who, saluting, went off to be assisted into his diving-dress.

Sub-lieutenant Arnold Hythe was generally regarded as a smart and promising young officer. These golden opinions were gained not by self-advertisement, for the sub was unusually reticent concerning his profession, but by sheer hard work and a consistent application to that great deity that should always be before the eyes of all true subjects of the King--Duty.

He held a First-class certificate in Seamanship, Gunnery, and Engineering; a Second in Torpedo, and also in what the Navy List terms "Voluntary Subjects"; he was a qualified interpreter in French and German, and had more than a smattering of Spanish and Italian. In addition to these intellectual qualifications he possessed a powerful physique, and had a sound reputation as an all-round athlete whilst at Dartmouth.

The latter portion of his time as midshipman and the first few months after his promotion to sub-lieutenant were spent in duty with the Fifth Submarine Flotilla, whose base was at Fort Blockhouse at the entrance of Portsmouth Harbour. But through some cause, to him quite inexplicable, he had been appointed to the "Ramillies." This was somewhat to the sub's disgust, but realizing that it was of no use repining over such matters, Arnold Hythe accepted the change with cheerful alacrity.

Banks and Moy, the two seamen divers who were also to descend, were already dressed. All that remained was for their copper helmets to be donned, the telephones and air-tubes adjusted, and the glass fronts screwed on.

"I don't expect you will find any actual evidence, and it will be lucky if you come across any circumstantial evidence," remarked Mr. Watterley, the first lieutenant. "But in any case, should you see anything of a suspicious nature, inform us before proceeding to investigate. I need not remind you that the east-going tide is making, and that the current will be running fairly strong in a few minutes."

"Very good, sir."

Sub-lieutenant Hythe was a diver of considerable experience. Ever since his first descent in the training tank at Whale Island he took naturally to the hazardous duty. Going under the sea had a peculiar fascination for him, whether it was in the hull of a submarine or encased in the cumbersome india-rubber suit and ponderous helmet of the diver.

The men at the air-pumps began slowly to turn the handles. The glass front plates of the sub's helmet were secured, and assisted by a seaman Hythe staggered awkwardly towards the head of the iron ladder.

Rung by rung he descended till the water rose to his shoulders.

"By Jove, the tide does run," he muttered. "If it's like this now, what will it be in another ten minutes?"

Raising one arm he waved to those on deck, then releasing his hold he allowed himself to drop into the deep. The "Ramillies" was anchored in nine fathoms, but ere the sub reached bottom nearly a hundred and twenty feet of life-line and air-tube were paid out. With an effort he gained his footing and commenced to walk in the direction of the ship's anchor, battling against the two-knot current that swirled past him.

Although the sun was shining brightly and the light at that depth ought to be fairly strong, the sand and mud churned up by the tidal current made it impossible to see beyond a few yards. With nothing to guide him, for the life-line was quivering in the swirling water, Hythe struggled stolidly in the supposed direction. He realized that he was practically on a fool's errand. The mysterious person or agency who had been responsible for attaching the message to the anchors of the squadron was not likely to remain upon the scene of his exploit, while already all the sought-for traces must have been obliterated by the tide.

Presently two eerie-looking shapes ambled towards him. They were his companions, Banks and Moy.

"Well, if I am going in the wrong direction, those fellows are making the same mistake," thought the sub. "So here goes."

Another thirty yards were laboriously covered. Here and there the divers had to make a detour to avoid the wavy trailing masses of seaweed, that, if not actually dangerous, would seriously impede their progress, while at every few steps numbers of flatfish, barely discernible from the sand and mud in which they were partially buried, would dart off with the utmost rapidity.

"Thank goodness, here's the shot-line," exclaimed the sub, as a thin rope, magnified under water to the size of a man's wrist, became visible in the semi-gloom. The shot-line, terminating in a heavy piece of lead, had previously been lowered to serve as a guide for the divers to work from.

Pointing in two opposite directions Hythe signed to the two men to begin their investigations, while he, taking a route that lay at right angles to the others' course, began once more to struggle against the current. Ere he had traversed another ten yards his feet slipped into a slight depression. It was the hole scooped out by the flukes of the "Ramillies'" stockless anchor.

"Could do with a lamp," he remarked to himself, then stooping he began to examine the bed of mud and sand in which he stood. Beyond the almost filled-in cavity and the faint traces of the sweep of the battleship's anchor-chain there was nothing to attract his attention. He turned to look at his own footprints. They were already practically obliterated, so it was hopeless to expect to find the footprints of the mysterious diver or divers who had contrived to visit each of the anchors of the battleships in turn.

"Anything to report?" asked a voice through the telephone.

"No, sir," replied the sub.

"Thought as much," said Watterley. "Merely a matter of form. You may as well come up. I'll recall the two men."

Sub-Lieutenant Hythe was not sorry to hear the order to return. Had there been any possibility of success he would have prosecuted his investigations with alacrity, but Spithead with an east-going spring tide running is no place to indulge in submarine excursions. The danger of getting life-line and air-tube foul of some unseen obstruction was no slight one.

"THE NEXT INSTANT HE FELT HIMSELF BEING HURLED VIOLENTLY BACKWARDS."
"THE NEXT INSTANT HE FELT HIMSELF BEING HURLED VIOLENTLY BACKWARDS."

Hythe adjusted the valve of his helmet prior to giving the recognized number of tugs on the life-line--the signal to be hauled up. The next instant he felt himself being hurled violently backwards by a sudden and irresistible swirl of water. Within ten feet of him a huge, ill-defined mass of what appeared to be bright metal tore past. He was just conscious of a vision of one of a pair of propellers thrashing the muddy water and the object was lost to view.

"What a narrow squeak!" he growled angrily. "By Jove, I shouldn't be surprised if Banks is done for. It's a submarine, that I'll swear, but not one of ours. Ours are painted a dull grey and that seems to be a huge moving mirror."

In spite of his strong nerves, a mild panic overtook the sub. He signalled frantically to be drawn up, and to his relief he found himself alongside the battleship.

Grasping a line that was thrown him, Hythe hauled himself along till he reached the iron ladder. Here he clung, too excited to attempt to climb, until a seaman descended and assisted him up the side.

"What's up, Mr. Hythe? You look as if you'd seen a ghost," exclaimed the Number One, as the front plate of the sub-lieutenant's helmet was removed.

"Are Banks and Moy safe?" gasped the young officer.

"Safe? Of course they are," replied Lieutenant Watterley, giving a hasty glance over the side to where two distinct clusters of air-bubbles marked the progress of the divers. "What have you seen? But no, say nothing more at present. Wait till you're out of your dress, and you can report to the captain."

Arnold Hythe sat down on a bollard and attempted to collect his scattered thoughts, while his attendant proceeded to remove his helmet and leaden weights. Ere his india-rubber dress was stripped off Banks and Moy appeared over the side.

"Well?" demanded the first lieutenant laconically.

"Nothin' to report, sir," replied Banks, while his companion signified corroboration by a nod of his head.

Mr. Watterley looked inquiringly at the sub. The flush upon his face had vanished and his features were white with excitement. Several of the officers had come up and were engaged in plying Hythe with questions, to which the latter paid no attention. He was still in a kind of stupor, the result of a sudden shock to his nerves.

"Now then, Mr. Hythe--why, what's the matter with you? Here, I must send for the staff-surgeon; I must, by George!"

Assisted by two of his brother officers the sub was taken below, and in a very short space of time Doctor Hamworthy succeeded in bringing him to a more normal state.

Meanwhile Admiral Hobbes, hardly able to conceal his impatience beneath a cloak of official reserve, was engaged in animated conversation with Captain Warborough upon the eventful incidents that had necessitated the return of the Fleet to Spithead.

"Commander-in-Chief coming off, sir!" reported the lieutenant of the watch.

Tearing as hard as her sixty horse-power motors could drive her the Admiral's pinnace containing the Commander-in-Chief, the Admiral-Superintendent of the Dockyard, and the military Governor of the Fortress headed towards the "Ramillies."

Received with due ceremony and formality the officials came over the side, and on being welcomed by Vice-Admiral Hobbes were taken below to the latter's cabin.

"Well, Hobbes, what do you make of this business, eh?" asked Sir Peter Garboard. "Have you taken any steps to investigate?"

"Sent three divers down," replied the Vice-Admiral. "I am even now awaiting their report."

"Then the sooner the better," rejoined the Commander-in-Chief.

Admiral Hobbes touched a bell and a marine orderly entered the cabin.

"Pass the word for Mr. Watterley."

The marine orderly saluted and doubled along the half-deck, nearly bowling over the staff-surgeon and the first lieutenant who were already on their way to make their report to the captain.

"What's this? Mr. Hythe frightened by something he saw beneath the surface?" demanded Vice-Admiral Hobbes.

"No, sir," replied Doctor Hamworthy. "He is suffering from a shock to the nervous system; the symptoms are almost identical with those resulting from a severe electric shock."

"You don't mean to say that Mr. Hythe is the victim of a submarine discharge?"

"I do not assert, sir; I merely stated my opinion based upon observations."

"And how is he now?" asked the Vice-Admiral impatiently.

"Fairly fit; he could be judiciously cross-examined," replied the staff-surgeon. "But, unless absolutely necessary----"

"It is absolutely necessary," interposed Admiral Hobbes; then turning to the first lieutenant he continued:--

"And what were the other men doing? I understand that there were two seamen sent down. Were they injured?"

"They saw nothing unusual, sir," replied Mr. Watterley. "I subjected them to a strict examination. They walked in opposite directions from the shot-rope, athwart the tide, while Mr. Hythe went dead against the current. The water was very muddy. The men said they could see about ten yards in front of them. Banks, after the question was repeated, said he fancied he felt a cross-current that might have been the following-wave of a submerged vessel moving at high speed----"

"By the by," interposed Sir Peter Garboard. "I suppose you ascertained that none of our submarine flotilla were manoeuvring at Spithead?"

"Oh, no, sir; or rather, I mean yes, sir," replied the harassed lieutenant. "We signalled to Fort Blockhouse and in reply were informed that F 1, 3, 7, and 9 of the 2nd Flotilla went out at 7 this morning for exercise off the Nab. Those were the only submarines under way from this port. I also asked them to communicate with the Submarine Depots at Devonport, Dover, Sheerness, Harwich----"

"I hope you didn't give the reason, by Jove!" exclaimed Sir Peter vehemently. "If the papers get hold of the news there'll be a pretty rumpus."

"I shouldn't be surprised if the Press hasn't received more information than we have," remarked Rear-Admiral Maynebrace. "It passes my comprehension how they manage it. One thing, it's no use trying to hush the matter up. We cannot expect to muzzle nearly five thousand men."

"Wish to goodness I could!" snapped Sir Peter. Then addressing Mr. Watterley, he added: "Oh, first lieutenant, will you please send for Mr. Hythe, so that we can hear his version of the business."

Five minutes later Sub-Lieutenant Hythe was shown into the Admiral's cabin. The young officer was still pale. His iron nerves had received a severe shock, but thanks to Doctor Hamworthy's attentions he was able to pull himself together sufficiently to give a fairly full account of what had occurred.

"How would you describe the submarine that passed so close to you?" asked Captain Warborough.

"She was quite unlike any of our types, sir. I noticed she was almost wall-sided, with a very flat floor. Instead of tapering to a point fore and aft she had a straight stem and, I believe, a rounded stern, cut away so as to protect the propellers."

"How many propellers?"

"Two, I think, sir. I distinctly saw the starboard one revolving. The eddy from it prevented my seeing anything more."

"H'm. By the by, had she a conning-tower?"

"I could not see, sir. Her upper deck must have been quite twelve feet above my head."

"What colour was she painted?"

"That, sir, I can hardly describe. I can only liken the sides to a huge mirror that reflected objects without reflecting the sunlight at the same time. As it was I could only see that portion of her that passed immediately in front of me. I could not even give an estimate as to her length, or even the speed at which she was travelling."

"You were capsized, I believe. Did anything strike you?"

"An under-water wave, sir, hurled me backwards. Nothing actually struck me, but I felt a strange paralysing sensation in my limbs, so that I could not make my way back to the shot-rope. All I could do was to signal to be hauled up."

"Then how do you account for the fact that this submarine craft passed close to you, and yet was unseen by Banks who was farther from the ship than you were?"

"I regret, sir, I cannot hazard an opinion," replied the sub.

"That will do, Mr. Hythe," said the Commander-in-Chief, indicating that the interview was at an end.

"Oh, by the way, Doctor," he continued, after the sub had left the cabin, "I suppose you have no doubt that this young officer actually did see this submarine? Is it possible that he was the victim of a hallucination?"

"From Mr. Hythe's medical sheet, and from my personal knowledge of his physical and mental condition, I have every reason to reply in the negative to both your questions, sir."

"Well, well, gentlemen," exclaimed Sir Peter, "we have a great task in front of us, with very little data to work upon. We have reason to suppose that there is a mysterious submarine commanded by an equally mysterious Captain Restronguet--a name that suggests that the fellow is French. We have definite evidence that by some unknown means that Captain Restronguet is able to execute extensive and fairly intricate work, namely, fixing those painted boards to the fluke of the anchors of the Fleet. How it was done has to be proved, and it must be proved up to the hilt, for even though no hostile act has been committed it is quite evident that the ships at Spithead were quite at the mercy of this unknown submarine. As far as the safety of the Fleet at Spithead is concerned, you, my dear Hobbes, are responsible. I, for my part, must take due precautions to prevent this submarine from entering the harbour, and I venture to assert, gentlemen, that when our preparations are complete, this Captain Restronguet and his submarine will be neatly trapped."

CHAPTER III.

THE MAN WHO WALKED OUT OF THE SEA.

Before night the news of the event that caused the manoeuvres to be hurriedly abandoned had been published in the papers. Most of the journals contented themselves with a brief account of what had transpired, based upon reports that had been obtained from men serving in the Fleet; for although liberty men were not landed communication with the shore had to be maintained. Other papers enlarged on the actual facts, and announced in double-leaded columns that a foreign submarine had attempted to fix mines to the hulls of the ships at Spithead.

Never had there been such conjectures since the time when some years previously an airship of unknown nationality had sailed over Chatham and Sheerness. People asked what was the use of making elaborate defences against aircraft when a submarine could unseen enter the most strongly fortified roadstead in the world and coolly tamper with the moorings of the Fleet?

Meanwhile the Naval authorities at Portsmouth, who regarded Captain Restronguet's visit as a slur upon their capabilities, lost no time in prosecuting their investigations. A stupendous obstruction, formed of several old torpedo nets fastened together, was thrown across the Needles Channel between Cliff End Fort in the Isle of Wight and Hurst Castle on the Hampshire shore; while a similar defence net was placed between the seaward extremities of the two new breakwaters on the eastern side of Spithead. All homeward bound shipping was forbidden to make for any of the ports within these obstructions, while an embargo was placed upon all merchant vessels about to leave Southampton, Portsmouth and Cowes, and their outlying ports. It was a drastic order, and quite unnecessary, but the country was almost in a state of panic.

Into the enclosed area every available trawler suitable for mine-sweeping, as well as all the dockyard hopper-barges fitted with appliances for "creeping" were kept busily at work, till hardly a square yard of the bottom of the Solent was left unexplored, and not until this particular work was completed did the authorities agree that the mysterious submarine might have left these waters almost as soon as Captain Restronguet had left his new-fangled cards upon the officers commanding H.M. ships at Spithead.

While these dragging operations were in progress the force of the tide through the Needles Channel, which often exceeds seven knots, tore away the nets thrown across that passage. Two days later the easternmost netdefence was removed, and it was then found that a rent thirty feet in length had been made in the steel meshes. Whether this was done by human or natural agency could not be determined, a minute examination of the fracture ending in nothing but heated arguments between the experts who had been called in to make a report.

On the same day that the torpedo net defences were removed the master of SS. "Barberton Castle" reported sighting two submarines lying motionless on the water, about fifteen miles S.S.E. of the Lizard. He stated that owing to the submarines being against the light he was unable to see them at all distinctly, yet he felt certain that they were of a totally different type from those of the British and French navies. They were so close together that the bows of one overlapped the quarters of the other, and thinking that they were in distress, he ordered the "Barberton Castle's" head to be turned in their direction. Directly the tramp answered to her helm both submarines dived simultaneously, and were lost to view.

The next morning Reuter's published a telegram from their agent at Cherbourg, announcing that the mysterious Captain Restronguet had brought his submarine into the harbour and at high tide had placed three dummy mines at the entrance to the docks in the naval arsenal. To each of the mines was a tablet on which was painted "Avec les assurances de ma plus parfaite consideration--Restronguet, capitan de sous-marin."

With the fall of the tide, that here exceeds twenty feet, these disquieting evidences were discovered, and within a few hours Captain Restronguet was the talk of all the cafés of Paris. The French, pioneers in submarine warfare, were now at a loss to explain how a submerged craft could, in broad daylight, enter the breakwater-enclosed harbour and run alongside the caissons of the docks without being discovered, while to deposit three bulky "mines" in water of not more than three fathoms in depth was an exploit that required a lot of explanation as to how it was done.

The transference of Captain Restronguet's attentions to the other side of the Channel relaxed the tension on the British shore. But, bearing in mind that Cherbourg is only a few hours' distance from Portsmouth, the naval authorities at the latter port were still on tenter-hooks.

A week passed. The First Battle Squadron of the Home Fleet still remained at Spithead, although under orders to proceed to the Nore at an early date.

At 11.15 one morning a startling incident occurred that, rightly or wrongly, was attributed in some manner to Captain Restronguet.

It was on Southsea beach, almost midway between the pier and the castle. The beach and parade were thronged with people, mostly visitors who had taken advantage of the Fleet's presence to enjoy the view of the ships. The sea was perfectly smooth, being unruffled by the light off-shore breeze; the tide was, however, running very strongly, for it was about the fourth hour of the ebb.

Suddenly a succession of shrieks from a group of children paddling in the water attracted the attention of persons in the vicinity, and to the astonishment of every one the head and shoulders of a man encased in a dull green metal helmet emerged from the waves.

For a few moments the man hesitated, then staggered out of the water. At the edge of the beach he sat down and began to remove his head-dress, that the onlookers noticed was unprovided with air-tube or life-line. He was apparently quite independent of an outside air-supply.

Surprise had hitherto kept the spectators at a respectful distance, although their numbers were momentarily increased by others, until a deep semicircle of gaping onlookers hedged the diver in on the landward side. But as soon as he began to take off his helmet the crowd swayed nearer and nearer.

The removal of the metal head-dress revealed the features of a man of about thirty years of age, clean-shaven and with closely-cropped dark-brown hair that had a tendency to curl. Without speaking a word the unknown drew a knife from his belt and began to hack rapidly at some contrivance at the back of his helmet. As soon as he had severed the part he was attacking he stood up and hurled it far into the sea. This done he calmly began to strip off the stiff fabric that composed his diving suit.

By this time the coastguard on duty at the look-out hut had noticed the crowd congregate, and through his glass saw that something unusual was happening and that a diver had come ashore. Since there were no Government diving boats anywhere in sight he naturally thought that it was a case for investigation, and the detachment of coastguards was promptly turned out.

"Here, sir, what's the meaning of this?" demanded the chief officer, forcing his way through the crowd. "Who are you, and how did you manage to get ashore here?"

"That I can easily explain," replied the unknown. "I am an inventor, and this diving-dress represents the result of seven years' work. I walked into the sea at Gosport a couple of hours ago, but, getting caught in the strong current running out of Portsmouth Harbour, I was swept a great distance until I managed to regain my feet. By walking in a direction due north as shown by my watertight compass I came ashore here. Needless to say I do not look for publicity, and all I wish is to pack up my discarded gear and go."

The chief officer looked at the stranger with mingled astonishment, admiration, and doubt. Never before had he known of a diver covering a distance of more than two miles, and that without the assistance of a boat containing the necessary apparatus for supplying the submerged man with air.

"Hanged if I know what to make of it, Smithers!" he said in an aside to his leading petty officer. "Perhaps he's a spy, or one of that blooming Captain Restronguet's crowd. This beats all creation!"

"Can't we detain him on suspicion?" asked Smithers. "I'll swear he's up to no good."

"I've half a mind to," replied the chief officer dubiously. "But, you see, they'll come down on me like a hundred of bricks if I exceed my duty."

"Invite him to the station, friendly-like," suggested the petty officer, "then, while he's there, you can telephone for instructions."

"I'll try it, by smoke!" ejaculated the chief officer, and approaching the unknown he asked if he would like to dry his clothes at the coast-guard station, since his ordinary garments, owing to the exertion in a confined space, were dripping with moisture.

"No, thank you," replied the submarine pedestrian. "All I want is to get a taxi, and make myself scarce. The attentions of so large a crowd are really embarrassing, and I am a man of a very retiring disposition. Had I expected this reception I should have vastly preferred to have landed in a more secluded spot."

With that he ignored his questioners and began to roll his diving suit into as small a compass as possible.

The coastguards were on the horns of a dilemma. They feared to make an unlawful arrest, while they might be severely brought to book for allowing the stranger to slip through their fingers, but there was nothing in the King's Regulations to prevent a man landing on a public beach, whether from a boat, hydro-aeroplane, or otherwise.

Just at that instant a policeman strolled leisurely up, and scenting a charge, produced his notebook and pencil.

"Hi! What's this you're up to?" he demanded, but the unknown totally ignored him.

"Can't he speak English?" asked the policeman of the coastguard officer.

"Rather," asserted the other emphatically; then in a lower tone he added, "Look here, we want to detain the man, but we cannot name a charge."

"I'll see about that," retorted the policeman. "Now, sir, your name and address, please."

"Allow me to inform you, constable, that my name is not 'Hi.' Since you addressed me as such you must not be surprised that your question was ignored."

A titter went up from the crowd, which had the effect of rousing the ire of the representative of the Law.

"Now, sir, your name and address, please."

"What for, constable?"

"For bathing off a public beach in prohibited hours."

"Don't talk rot!" exclaimed the unknown indignantly.

"Very good; since you refuse I have no option--I arrest you. Any statement you make may be used as evidence against you. Come along with me."

Attended by the surging crowd the policeman escorted his charge to the road, where a cab was hailed. The chief officer of coastguards was requested to accompany the prisoner as a witness, and the three entered the vehicle and were driven to the police-station.

Here, in order to gain time, the prisoner was formally charged with unlawful bathing, and as the Court was still sitting at the Town Hall he was ordered to be taken there at once. The chief officer meanwhile communicated with the naval authorities by telephone, expressing his opinion that the diver was a member of the mysterious Captain Restronguet's submarine.

But the prisoner never arrived at the Town Hall. When the cab stopped outside the court a policeman was found insensible on the seat. The floor had been violently ripped up, and unknown to the driver and the constable on the box the suspect had got clean away. By some inexplicable agency the unknown had deprived his captor of his senses, and the mystery of Captain Restronguet had entered into another phase.

CHAPTER IV.

THE SIGNAL FROM THE DEPTHS.

"Naval appointments: The following appointment was made at the Admiralty this afternoon: Sub-Lieutenant Arnold Hythe to the 'Investigator' for special duties (undated)."

This item, in the Stop-Press columns of an evening paper, was shown to Sub-Lieutenant Hythe by one of his brother officers.

"You are a lucky dog!" exclaimed the latter. "My Lords evidently recognize your capabilities as a diver. Well, good luck, old man. I hope you'll play the chief part in running down this plaguey fellow. Hang it all, I cannot see that he's doing any harm, except that all leave is stopped until something is done to stop his little antics."

"Yes, that is hard lines," assented the sub. "But I'll do my level best, no doubt."

H.M. surveying vessel "Investigator" was lying in dock at Portsmouth, and was under orders to proceed to sea at the first possible opportunity, her errand being to endeavour to locate and capture the submarine that, it was generally agreed, was still in the vicinity of Spithead.

To cope with the situation a special Bill had been hurriedly introduced into Parliament making it an offence against the Naval Secrets Act for any person to manoeuvre a private submarine within five miles of specified naval ports. The Bill received the Royal assent and became law within thirty-six hours after the escape of the suspect arrest on Southsea beach, an individual who was generally accepted as being the man of mystery, Captain Restronguet.

The fellow's diving gear, or at any rate the major portion of it, remained in the hands of the authorities. After being subjected to a lengthy research at the hands of the Diving School at Whale Island the following report was issued confidentially: "The helmet is of a metal hitherto unknown, possessing all the advantages of aluminium, without the known disadvantages. It is a departure from the usual form, having a ridge-shaped projection in front, possibly to lessen the resistance to the water when moving on the bottom of the sea. The helmet is also valveless, the air, chemically prepared, is by some means kept at a fairly high pressure, sufficient to distend the suit in order to do away with any discomfort to the wearer by reason of the weight of water. The suit is made, not of rubber as was at first supposed, but of an unknown quality of flexible metal. When distended it also presents an edge in front, in order to minimize lateral resistance. How the air is purified is still a secret, the apparatus for so doing having been detached and thrown into the sea by the unknown. A diligent search had failed to produce this important item. Undoubtedly the suit, when complete, is far in advance of any now used in the Service."

A careful watch was maintained along the shore, the coastguards stationed in the district being temporarily augmented by men drafted from more remote places. Yet no trace of the mysterious submarine on the surface was to be seen. How, when and where the craft replenished her fuel necessary for locomotion purposes and her provisions and fresh water completely baffled the naval experts; for a fortnight had elapsed since she announced her appearance at Spithead, and save for the temporary visit to Cherbourg all evidence pointed to the fact that she was still within the limits of the Port of Portsmouth.

Arnold Hythe duly joined the "Investigator" as officer in charge of the diving parties. Twelve first-class seamen-divers were drafted into the ship, while special gear for "creeping" was placed on board. Submarine apparatus for recording by sound the presence of submerged craft under way was also installed, so that it was impossible for any vessel making the faintest noise to approach within two miles of the "Investigator." Even the wavelets lapping the bows of a passing fishing-smack would be reproduced with unerring fidelity. Just before high water the "Investigator" was undocked; steam was soon raised, for the surveying vessel, being of an old type, was driven by reciprocating engines and oil-fed boilers. Almost at the moment of casting off the hawsers and springs came news that caused the greatest disappointment amongst officers and crew.

Captain Restronguet had, according to the latest report, turned up in a totally different spot. This time he devoted his attention to the German port of Wilhelmshaven. Here his visit was not of a comparatively harmless nature, for the locks of the Kaiser Wilhelm Canal were totally demolished by means of a powerful explosive. The battleship, "Karl Adelbert," that was about to pass out of the canal, was badly damaged. In the confusion six destroyers and submarines were ordered from Cuxhaven. They were quickly on the spot, but no trace of the mysterious submarine was to be seen, except a small barrel painted white and green, with the name "Captain Restronguet" in bold letters.

The "Investigator" was immediately ordered to make fast one of the buoys in Portsmouth harbour. Her special mission was, for the time being at least, over; a far more serious situation had arisen.

The German Government, supported almost entirely by the Press of that country, actually suggested that, since Captain Restronguet had committed an act of piracy against the German Fleet while he had refrained from so doing on his visit to Portsmouth and Cherbourg, Great Britain and France were secretly aware of the identity of this modern buccaneer, and that they had encouraged him to make an unlawful act of hostility towards a friendly Power.

Three army corps were hastily ordered to Hanover and Schleswig-Holstein, the German High Sea Fleet was ordered to assemble at a rendezvous off Heligoland, and every available battleship, cruiser, destroyer and submarine in the Baltic was sent through the Great Belt and around the Skaw to augment the naval armament already in the North Sea.

The British Government met the situation with promptitude, firmness, and calmness. The First and Second Home Fleets settled at the Nore; the Third Home Fleet, which happened to be cruising off the Orkneys, was ordered to the Firth of Forth. Troops were quickly entrained at Aldershot and Salisbury Plain for the defence of the East Coast, while the Territorial Army and the National Reserve were called up for garrison duty. At the same time a statement was made to the German Ambassador in London in which His Majesty's Government totally repudiated the suggestions that Captain Restronguet held any authority, either direct or indirect, from the Crown.

To this the German Press retorted by pronouncing the declaration to be a diplomatic lie, and unanimously urged the Imperial Government to recall its ambassador. All privately owned airships in the Fatherland were taken possession of by the authorities, and ordered to the newly-formed Government aerodrome at Munster, a Westphalian town sufficiently far from the sea to be out of the reach of the guns of hostile warships, yet within a few hours' flying distance from the East Coast of England.

The struggle, if it came off, would be a desperate one. Both fleets were almost numerically equal, the British having a slight margin of superiority, but in aircraft the Germans held a decided advantage. In the science of warfare there was little to choose between the two, so that as far as Great Britain was concerned the issue depended upon whether the British tars still retained their bull-dog tenacity that characterized their forefathers in the days of the old wooden walls.

In spite of the British Government's coolness and determination the country, that had passed through so many international complications with safety, was in a panic. Consols dropped lower than ever they had been known to fall; prices immediately rose with a bound, and within twelve hours of the receipt of the disquieting news of Captain Restronguet's escapade at Wilhelmshaven the country was experiencing the horrors of war without actually being engaged in a desperate conflict on which her very existence depended.

On the morning following the momentous news from Wilhelmshaven a message appeared in The Times. It was a statement purporting to come from Captain Restronguet, in which he emphatically denied ever being in German waters, and that as a proof he would give a sure sign of his presence off the shores of Great Britain. At noon of that very day he would give a demonstration of the irresistible powers at his command at a spot somewhere between the Horse Sand Fort and the entrance to Portsmouth Harbour.

"Do you think it is a joke, sir?" asked Sub-Lieutenant Hythe of the navigating officer of the "Investigator."

"What do you think of it, may I ask?" replied Lieutenant Egmont guardedly.

"Personally, I hardly consider that it is a hoax. You see the notice appeared in the Personal Column."

"And paid for in the usual manner, I suppose."

"But the Business Editor has the option of refusing any advertisement."

"That's what makes me think there's something genuine about it. Again, the paper has a short leader on it: non-committal, it is true."

"But how can a fellow cooped up in a submarine that is being watched for all along the coast contrive to get ashore to send off a message to The Times?" asked Egmont. "How can he keep in touch with affairs? Why, in order to have that notice inserted he must have heard of the Wilhelmshaven business within an hour or so of its occurrence."

"Admitted; but all the same Captain Restronguet is a modern magician in submarine work. I should not be surprised if he has a perfect wireless service at his command. By the by, has Captain Tarfag orders to proceed to Spithead?"

"No, and he told me himself that he didn't want to be sent on a wild-goose chase. The Admiral has ordered a couple of aero-hydroplanes to manoeuvre over the place indicated at noon, and to keep a sharp look-out for any suspicious object under the surface. There they are, by Jove!"

Both officers stopped in their "constitutional," a to and fro promenade of the short quarterdeck of the "Investigator." A dull hum, momentarily growing louder, announced that Nos. 27 and 29 Aero-hydroplanes had left their sheds on the shores of Fareham Creek and were rising rapidly to the height of one thousand feet.

As soon as this altitude was reached both aero-hydroplanes, abandoning their spiral motion, leapt forward, and passing high above the shipping in the harbour were soon mere specks floating in the blue sky.

Watch in hand the sub waited. It was close on the fateful hour of noon. To and fro, in elliptical curves, the aero-hydroplanes maintained their lofty vigil, each turning at almost the same moment and passing within fifty yards of one another.

Twelve o'clock! Hythe and his brother officer exchanged glances. Captain Tarfag ascended the bridge, and hailing the wireless operator and the yeoman of signals by telephone, demanded if either of them had received news of the mysterious submarine.

"No message has been received at the Semaphore Tower, sir," they replied. The captain gave a deprecating shrug and descended the ladder.

"They're coming back, by Jove!" exclaimed Lieutenant Egmont, after another ten minutes had elapsed. "That proves that the message was a hoax."

"They may have seen something," suggested the sub, unwilling to have his opinions shattered.

"Not they. Do you mean to tell me that if they had spotted anything suspicious they would not follow it up. I was----"

The navigating officer's words were interrupted by a heavy detonation, like the report of a fourteen-inch gun fired with a full charge. Beyond the houses of Old Portsmouth, and at an altitude of about five hundred feet, a cloud of yellow smoke hung almost motionless in the still air. The aero-hydroplanes, overtaken by a wave of disturbed atmosphere, lurched violently, although fully a mile from the actual place of the explosion. It required all the efforts at the command of their crew to save the aerial vessels from destruction, but recovering their equilibrium by superb manoeuvring of the planes, the aero-hydroplanes turned and headed towards that portion of Spithead over which they had so lately been reconnoitring.

"By Jove! There's pluck for you!" ejaculated Egmont. "That was Restronguet's signal. If it had been to time those fellows would have been done for; and now they're trying to spot the submarine. You were right after all, Hythe. That paragraph was not a hoax."

Captain Tarfag was in the middle of lunch when the detonation was heard. He rushed on deck, and realizing that it was a case where waiting for orders would be detrimental to success, he ordered the moorings to be slipped.

Within the harbour all was commotion. Nearly a dozen destroyers, two scouts, and three tugs were making for Spithead, while five more aero-hydroplanes and the naval airship "Beresford" were ploughing their way against a stiff south-easterly breeze towards the scene of Captain Restronguet's latest demonstration.

One noticeable result of the explosion was that within a quarter of an hour the weather, hitherto perfectly calm, became changed. Clouds were rapidly banking up, with every appearance of a heavy thunderstorm, while the placid waters of Spithead were now white with foam-crested waves.

For two hours the "Investigator" and her consorts cruised up and down, betwixt the Nab Lightship to the eastward and Cowes to the west. Aloft the aircraft kept anxious watch and ward, till it seemed impossible that any craft could lie at the bottom of that comparatively shallow roadstead without being discovered.

"Nothing to report," came the wireless message from the aircraft with monotonous regularity. Captain Restronguet had outwitted the eyes and ears of the British Fleet.

Upon the "Investigator's" return to Portsmouth Harbour it was possible to obtain details of what had occurred: The sea wall in front of Southsea Castle was crowded with people who, half-doubting, were yet sufficiently curious to see whether the promise in The Times would be redeemed. They saw the two aero-hydroplanes approach and manoeuvre over the pre-arranged area. They heard the clocks chime the hour of twelve. They waited a few moments longer, nothing happened, so with a derisive cheer they began to disperse. Some remained--mostly those of the leisured class who were not restricted by the midday meal that the British workman holds up as an established institution.

Suddenly--it was exactly at eleven minutes past twelve--a column of water leapt vertically upwards at less than four hundred yards from the shore. There was a shrieking sound like the screech of a high velocity projectile, followed by a detonation so powerful that most of the spectators on the sea-front were deaf for days afterwards. The ground trembled, several persons were overthrown; the windows of several houses overlooking the common were broken. Expecting a shower of scraps of metal from the bursting projectile the terror-stricken crowd broke and ran, but curiously enough no one could afterwards be found to report that anything of a solid nature fell to earth. Captain Restronguet's token was merely an explosive rocket of high power.

That same afternoon news came that a German seagoing training-ship, the "Sachsen" was sunk by some unknown means in Kiel Harbour, and another green and white buoy bearing Captain Restronguet's name, was found floating over the wreck of the sunken vessel.

By what manner, incomprehensible beyond the wildest dream of fiction, could this Captain Restronguet be at Portsmouth just after noon and at Kiel, in the Baltic Sea, two hours later? Was his submarine in possession of supernatural powers whereby he could annihilate space and practically conquer time? The theory was no sooner advanced than it was regarded as utterly impossible; the opinion that Captain Restronguet was, after all, not responsible for the outrages at Wilhelmshaven began to gain ground both in Great Britain and Germany.

In naval and military circles the importance of the offensive powers of the mysterious submarine were fully commented upon. It was recognized that submarine warfare was more than likely to regain the supremacy that had been wrested from it by aircraft. Here was a submerged vessel, invisible although only in seven fathoms of water, that could project a shell charged with a high explosive vertically to a great height. Although not in the accepted sense of the word an aerial torpedo, the rocket had seriously affected the stability of the two aero-hydroplanes that were at a distance hitherto considered as a safe margin. Had it been an aerial torpedo instead of a rocket the result would have been terrible to contemplate.

The Chronicle appeared next morning with an apology and manifesto from Captain Restronguet. He regretted that, owing to the proximity of the two aero-hydroplanes, he was not able to give his promised token precisely at the hour of twelve, and trusted that the British public would realize that the slight delay was due solely to his desire to avoid loss of life and property to His Majesty's subjects. He once more repudiated any suggestion that the Kiel outrage was carried out at his instigation, and, further, as a proof of good faith, he hoped to give an exhibition of the forces at his command this time in Plymouth Sound. At 6 a.m. on the following day, unless unforeseen circumstances prevented, he would make known his presence in Cawsand Bay.

As soon as this decision was communicated to the Admiralty telegraphic orders were sent to Portsmouth, ordering the "Investigator" to proceed at once to Plymouth, where, co-operating with the surveying-vessel "Mudlark," she was to make every effort to effect the capture of Captain Restronguet's submersible ship.

CHAPTER V.

CAPTURED.

At 4 a.m. the "Investigator" arrived off the eastern arm of Plymouth Breakwater, whence she signalled to Devonport Dockyard the news of her arrival. The lights of the "Mudlark" were soon afterwards observed as she threaded her way through the tortuous passage between Drake's Island and the mainland, and in company the two vessels bore away in the direction of Penlee Point.

Officers and crew were in a state of suppressed excitement. If Captain Restronguet were a man of his word, as he evidently was, his capture seemed certain, for the waters of Cawsand Bay were admirably suited to the arrangements which Captain Tarfag had made for his great coup.

By dawn the vicinity of the bay presented a scene of animation. The cliffs between the village of Cawsand and Penlee Tower were black with people. Thousands of the good folk of the Three Towns had crossed over to Cremyll and thence, mostly on foot--for the number of vehicles available was quite inadequate--had tramped the hilly road across Maker Heights. Kept at a respectful distance by a strong patrol of picquet-boats were hundreds of crafts of all sizes, from the frail pleasure skiff to the weatherly fishing-smacks and the local ferry steamers. Beyond these lay several battleships and cruisers whose presence had not yet been required in the North Sea; and since they were of an older type, with masts and unprotected decks, they were literally covered with human beings.

A better place to effect the capture of the submarine could hardly be found, for the depth shelved gradually from twenty feet close inshore to forty along a line joining the extremities of Penlee and Picklecombe Points.

The after-decks of the two surveying vessels were buried beneath piles of nets composed of three-inch tarred rope intermeshed with flexible steel wire. These could be "paid-out" with considerable rapidity, and being buoyed and weighted would sink automatically till their upper edge was ten feet below the surface and their lower edge the same distance from the bottom. Both vessels were to start simultaneously from the western extremity of the Breakwater and head for Penlee and Picklecombe Points respectively, where strong parties of seamen were ready to haul the ends of the nets ashore.

At half-past five Captain Tarfag gave the order to commence paying out the obstructions, and at a steady six knots the "Investigator" steamed ahead, her consort, being a slower vessel, having to take the shorter distance--that between the Breakwater and Picklecombe. Precisely at five minutes to six the shoreward ends of the nets were secured.

"If Captain Restronguet keeps his promise he is already safe in the net!" exclaimed Lieutenant Egmont. "You see, there is nothing to prevent him from giving his signal at the appointed time. There are no vessels in the bay, and no aircraft overhead."

"It will be a nasty shock to those craft if he fires a rocket over their heads," remarked Arnold Hythe, indicating the crowd of small vessels that, in spite of the picquet-boats, were continually edging nearer and nearer in the desire of their occupants to see more of the promised "fun." "But what is going to happen when we trap the submarine?"

"Oh, Captain Tarfag and I have already settled about that," replied the navigating lieutenant confidentially. "As soon as we are certain that the submarine is in the bay parties of men ashore will drag in the nets, till the craft is either stranded or her propellers are hopelessly entangled in the rope and wire strands. But stand by! It's close on six."

A hush fell on the assembled multitudes. Every face was turned in the direction of the tranquil bay, where, save for a slight ground-swell, the water was unruffled.

The crowds were not kept waiting. Punctually to the minute, at less than four hundred yards from shore and almost abreast of the little village that gives the bay its name, a green and white flag, hanging limply from a staff by reason of the saturated state of the bunting, rose above the surface. Then urged by some unseen power the flag-staff ripped its way through the water, throwing the spray in silvery cascades. Then it described a circle of less than a hundred yards in diameter, then as abruptly as it appeared the emblem of the mysterious Captain Restronguet vanished beneath the surface.

"We've got him, by Jove!" shouted Captain Tarfag.

Four blasts in rapid succession from the "Investigator's" syren was the signal for the men ashore to haul away.

Slowly the ponderous line of netting was dragged through the water. Fortunately there was little or no tide and hardly any floating weed to render the task more difficult than it might otherwise have been; nevertheless it required an hour's hard work ere the enclosed space marked by the line of buoys appreciably diminished.

All the while signals from the "Investigator" were being exchanged with the look-out tower on Penlee Point. Again and again came the disquieting news "No sign of submarine."

"Surely in fifty feet, with a clear sandy bottom, those fellows up there ought to detect the craft!" exclaimed Lieutenant Egmont impatiently.

"I failed to see it at ten yards, although I admit the water was awfully muddy," said the sub.

"But what if she's given us the slip?" continued the navigating lieutenant. "Look, man; in another half an hour the bight of the net will come ashore."

"A lot may happen in half an hour," replied Hythe. "Unless she uses an explosive to clear a passage we have her safe enough, and I do not think that Captain Restronguet will resort to extreme measures, judging how he has already behaved in British waters."

"What I want to know is how Captain Tarfag proposes to take possession of her, when she is held up in the nets. He told me he had a plan, which we are now carrying out, but not a word more on the subject would he say, so, of course, I couldn't offer any suggestions."

"It is nearly high-water springs," observed the sub. "That means that we could get her sufficiently high for the falling tide to leave her stranded. Hulloa! What's that?"

A sudden commotion at less than a cable's length on the "Investigator's" starboard bow showed that some large moving object had been held up in the stout meshes of the net. Myriads of air-bubbles rose to the surface, causing a considerable patch of broken water on the otherwise smooth sea. A light-draught picquet boat, with two heavy grapnels made ready to lower, dashed over the submerged net. The iron hooks fell with a dull splash.

"Holding, sir!" shouted the midshipman in charge of the picquet-boat.

"Good! Belay there!" replied Captain Tarfag. "Drop the second grapnel, and I will send a boat to bring the rope aboard."

The working parties ashore desisted in their efforts. All the power at their command could not bring the nets home another fathom. Held by the submarine, that in turn was tenaciously anchored to the bottom of the bay, they absolutely refused to be hauled in. A sounding gave a depth of seven and a half fathoms.

"Mr. Hythe," shouted the captain.

The sub took the bridge-ladder at top speed, and saluting, awaited his chief's orders.

"Oh, Mr. Hythe," continued the latter. "I want to send a couple of men down to report on the position of the submarine. If she's anchored, get them to find out in which direction her cable leads and we can then creep for it. Also I want to ascertain whether it be possible to lower the bight of a chain under her bow and stern. If that can be done I'll signal to the Dockyard for a couple of lighters, and we'll lift the craft with the rising tide and take her straight into the Hamoaze. But mind, Mr. Hythe, I wish it to be distinctly understood that volunteers only are required for this service."

"I should like to descend, sir."

"You! Why I thought, by Jove, you had enough of it on the last occasion you encountered the submarine, judging by all accounts. But of course, I should be glad to accept your offer. Take two men with you."

The sub again saluted, and on gaining the quarter deck ordered the bo's'un's mate to pipe away the diving-party.

Of the qualified divers every man-jack expressed his desire, as vehemently as the presence of the officers permitted, to go down. Hythe would have much preferred to have taken Moy and Banks, who at his request had been transferred from the "flagship, but favouritism he strongly set his face against.

"Numbers one and two front rank men, fall out."

Number one was a tall, broad-shouldered Irishman named O'Shaunessey, a man who still retained the Wexford brogue. Number two was a dapper little Cockney, Price by name, who had the distinction of holding the Navy record for deep-sea diving.

"Look here, Price," said the sub, "I'm going down too; but I want you to clearly understand what to do. I will try to locate the Submarine, and see if there is any possibility of raising it by means of a grapnel. You I want to get as close to the bows as you can without much chance of being seen and report by telephone what forefoot she has, if any, and if there's any chance of slinging her at that end. O'Shaunessey, I want you to examine the after-end, and find out what overhang she has; also whether her propellers are foul of anything."

"Hurry up, there!" ordered Captain Tarfag. He was naturally anxious that his prey should not escape him, for, although the strain on the picquet boat's grapnel-line was maintained, the bubbles no longer rose from the enmeshed submarine.

Hythe was the first to descend, from a boat lowered from the "Investigator." The conditions beneath the surface were far more favourable than on the occasion of his descent at Spithead, for the bottom was of firm white sand, and the tidal current was barely a quarter of a knot.

Ere he had traversed fifty yards an ill-defined mass loomed up ahead of him. It was the submarine, exaggerated out of all proportion by the refractive properties of the water.

With rapidly beating heart the sub continued to advance. Suddenly he saw a figure in diver's dress approaching. He stopped. The stranger stopped too.

"I'll wait for Price and O'Shaunessey," thought Hythe, and still keeping his face towards the unknown diver he laboriously retraced his steps. As he did so the stranger did likewise.

"I wonder----" thought the sub, and raising his right arm he saw the unknown diver simultaneously raise his left. Hythe was confronted by a magnified reflection of himself. The sides of the submarine were made of a mirror-like substance.

Keeping a respectful distance from the submerged craft Hythe walked towards, but parallel to, the bows. Presently he became aware that he was passing under the lowermost edge of the net, that, with elongated meshes, was stretched tightly across the upper portion of the stem of the submarine.

Since nothing had attempted to molest him, Hythe's sense of confidence rose.

"No, they wouldn't dare play the fool now," he reasoned. "There's no escape for them, and they will make the best of a bad job by surrendering at discretion as soon as the lighters sling her clear of the bottom. I wonder where her cable is?"

No signs of the submarine's anchor and chain were visible. There were hawse-pipes--two on the starboard bow and one on the port bow, but in none of them was a stockless anchor, or indeed one of any description. The hawsepipes were partly concealed by the nets, but the meshes were sufficiently distended to make the sub certain on that point.

Keeping his eyes fixed upon the ground Hythe walked on, thinking that, from the position of the vessel, he would eventually stumble over an anchor and chain lying half-buried in the sand. At length he came to the limit of his life-line, his search unrewarded.

"That's completely stumped me--middle wicket, by Jove!" he muttered. "A looking-glass submarine fixed as tight as a limpet to the sand, and not an anchor to be seen! All in good time, I suppose. When we get her into Plymouth we'll find out all we want to learn soon enough."

With that he turned and began to make his way round the submarine once more.

"Oh, there's O'Shaunessey!" he said to himself, as a huge helmeted figure came shambling along through the semi-transparent water. "I wonder what---- Great Scott!"

Arnold Hythe came to an abrupt stop. The diver approaching him was not O'Shaunessey. The Irishman's helmet was provided with an air-tube, and a life-line encircled his chest; this fellow had neither. He was one of the crew of Captain Restronguet's submarine.

The sub was not devoid of personal courage. The sight of the strange diver advancing in his direction aroused all the bull-dog fighting instinct in him.

"All right, my fine fellow!" he muttered. "I'll see if I can't tackle you."

Unhesitatingly he advanced towards the stranger. The latter, pausing a brief instant, held up one hand as if warning off his rival, but seeing that Hythe was intent upon grappling with him he stood on his guard.

The sub had no compunction. Although he could not under present circumstances summon the man to surrender in the King's name, he realized that, by virtues of the special Act of Parliament, he was authorized to summarily arrest any member of Captain Restronguet's command.

The next instant the two divers were locked in a close embrace, Hythe endeavouring to bring the man's arms to his sides, while at the same time he shouted through the telephone for his comrades in the boat to haul him to the surface. The unknown struggled desperately, striving to pass one heavily-leaded boot behind the sub's ankle. For ten seconds they grappled in the eerie depths of the sea, then Hythe found himself being dragged along the sandy bottom. His signal to be hauled up was being answered, and the steady strain on the life-line told him that unless anything unforeseen occurred another minute would find him and his captive at the surface.

On and on, over the yielding sand the two men were dragged, for the long scope of rope prevented an immediate upward ascent. Suddenly the unknown diver wrenched one hand free. He drew his knife, the blade glinted dully in the pale green light, and with a steady motion severed the life-line.

"Great heavens! He'll sever my air-tube next," thought the sub, but, apparently content with the advantage already scored, the fellow dropped his knife and tightened his grasp upon his antagonist.

"Blow me up!" gasped Hythe through the telephone, but although the men at the air-pumps redoubled their exertions the extra pressure of air escaped through the valve in the young officer's helmet, since he was unable to close it.

"I am attacked. Tell O'Shaunessey and Price to come to my assistance," exclaimed the sub. In spite of his powerful physique he was not even holding his own. He had bitten off more than he could chew.

During the struggle the sand churned up by the feet of the wrestlers rose till it was almost impossible to see more than a few feet away. Several times Hythe gave a hasty glance to see if his men were coming to his aid--but no.

Four grotesquely-attired figures appeared through the sand-blurred water. With a feeling of dismay the sub realized that he was hopelessly outnumbered. Since he had taken the initiative in provoking the contest he knew that he must expect to accept the consequences; yet he determined to resist as long as his strength of body and mind remained.

Powerful hands grasped him by the arms and legs. He was overthrown and lifted into a horizontal position. Even then he kicked out strongly till his captors, having good cause to fear his leaden-soled boots, desisted in their efforts to secure his legs.

A loud buzzing--the hiss of escaping air--told him that the worst was at hand. The minions of Captain Restronguet were unscrewing the union of his air-tube.

CHAPTER VI.

FACE TO FACE.

The hissing sound stopped. Instead, under a pressure of nearly two and a half atmospheres, the water rushed into the disconnected valve. In five seconds it had risen to the sub's knees. Then the inrush was checked.

It was useless to struggle, but with an uncontrollable longing to wrench himself away from his captors, rather than be drowned like a rat, Hythe persisted in his efforts, till he realized that he was in no immediate danger of being suffocated. In the place of the air pumped in from above--air that was anything but fresh--came a cool, invigorating vapour strongly charged with oxygen.

He no longer appealed for aid. He knew that with the air-tube and life-line the telephone wire had been severed. He was cut off from all intercourse from above. Even his air supply was self-contained.

Instinctively he felt certain that he would be carried off to the mysterious submarine. Curiosity prompted him to accept the situation with equanimity, his inborn fighting disposition urged him to resist. If he were to be made a prisoner he would let his captors know that the liberty of a British officer is not lightly lost.

It was a strange procession on the sandy floor of Cawsand Bay, for others of the submarine's crew had come upon the scene, and surrounded and held by five weirdly-garbed and helmeted men Hythe was frog-marched towards the huge submerged vessel.

A dull patch in the side of the craft indicated that a portion of her plating had been swung back, revealing on closer inspection a door about five feet in height and thirty inches wide.

Here the sub saw his chance. With outstretched arms and legs he defied the crowd of captors to pass his resisting body through the narrow aperture. Twice he almost freed himself from their clutches. The oxygen-charged vapour he was breathing accentuated his fighting instincts, and mainly through sheer delight at being able to thwart his antagonists he lashed out right and left.

Still retaining their hold the men began to lose patience. One of them turned and looked at another who was standing by. The look was understood. Drawing a small instrument resembling a two-pronged fork, from a sheath attached to his belt, the fellow advanced towards the young officer.

Hythe, still resisting, saw the action.

"I wonder what he's up to?" he muttered. "Going to puncture my suit, I suppose, and half-drown me. Take that, you under-handed rascal."

With a sudden wrench he freed his right hand, and clenching his fist hit madly at the diver's front plate. Had the blow struck home the glass would in all probability have been broken, but the man stepped backwards and the sub's fist encountered water only. That attempt led to Hythe's undoing, for two stalwart fellows seized him by the arm of his india-rubber suit between wrist and elbow. Held as in a vice he was unable to draw back his hand, the diver with the fork-like instrument immediately applied the points to the officer's bare knuckles.

A powerful electric current passed through him. He writhed; his limbs jerked with uncontrollable spasmodic movements, till, his spirit literally cowed, he was unresistingly carried through the aperture in the side of the submarine.

The panel glided to, smoothly and easily, leaving the compartment in utter darkness. Then came the sound of powerful pumps at work, and soon, by the weight of his helmet, Hythe realized that the water was being expelled. Within a minute and a half of the time of entering the place the sub was no longer in the sea, although he was under it.

A bell rang and another door opened, revealing a fairly spacious compartment well lighted by electricity. The floors, walls, and ceiling were of metal coated with a substance resembling coarse cement. Along one side were racks and pegs to take the diving equipment, several complete suits being not then in use. On the other side were coils of rope, lengths of chain, oars, grapnels, boathooks, and other gear used on board ship, while a folding canvas boat in three detached sections occupied a considerable part of the available space. On the bulkhead in which was the sliding-door by which Hythe and his captors had entered the compartment were various switches for controlling the ejecting pumps, the intake valves, and the lighting of that section of the vessel. In the other transverse bulkhead was also a door, fitted with a watertight sliding hatch. On either side of this doorway were complicated machines of which Hythe could neither make head nor tail.

Feeling more like a thoroughly cowed puppy than anything else he could liken himself to, the sub was divested of his diving-helmet and suit. The former was placed on the rack beside the others, the suit, not being of the same pattern as that of his captors, was hung up apart from all the rest. All this while the divers retained their head-dresses. They did not even remove the glass plates. As soon as the sub was free from the encumbrance of his diving-dress three men entered from another compartment.

They were tall, broad-shouldered fellows, clean-shaven, and with dark crisp hair. From their appearance they might be near relations, possibly brothers. They were clad in dark-blue jerseys and trousers, and dark canvas shoes, and looked more like yacht hands than the crew of a submarine.

"The captain will be pleased to receive you, sir," announced one in good English, with a west-country accent that a foreigner could not possibly acquire, saluting as he spoke. "What name shall I give, sir?"

The young officer hesitated a moment, then, reflecting that it was of no use beating about the bush, replied, "Arnold Hythe, Sub-Lieutenant of H.M.S. 'Investigator.'"

"Very good, sir; will you please step this way?"

The effect of the electric shock was beginning to wear off, nevertheless the sub felt in a very chastened spirit as he followed his guide, the other two men keeping in the rear. Hythe methodically took count of the number of paces he made as he walked along a narrow alley-way on either side of which were doors in the longitudinal bulkheads. Fifteen steps brought him to a stout transverse bulkhead, in which he noticed were two sliding-doors face to face with a space of about six inches between. Beyond, the corridor continued for another twenty paces, terminating at a door that was partially concealed by a heavy curtain.

"Sub-Lieutenant Arnold Hythe, of H.M.S. 'Investigator,' sir!" announced the man.

"Come in, Mr. Hythe!" exclaimed a deep, sonorous voice.

The guide stood aside, and allowed the sub to pass.

Standing in front of two electric lamps so that his face was in deep shadow was the modern submarine magician, Captain Restronguet. He had evidently taken up that position with deliberation, for he had the advantage of being able to scrutinize closely his visitor and at the same time partially concealing his own features; but the sub could see that the captain was a well-made man of about six feet two inches in height, with broad, square shoulders and massive limbs.

He was dressed almost as quietly as the three men who had accompanied Hythe from the divers' dressing-room and who were now standing at attention just inside the doorway. He wore a white sweater, dark-blue trousers, a double-breasted serge coat and white doeskin shoes, while on a writing desk by his side lay a canvas-covered cap of the style in vogue at Cowes during the yachting season.

"I am very pleased to make your acquaintance, sir," continued Captain Restronguet, holding out his hand.

Hythe hardly knew what to say. Had he been told that a quarter of an hour previously he would probably have told the captain to go to Jericho, but the antagonistic spirit had left him.

"And so am I, sir," he replied simply.

"Thank you," replied Captain Restronguet, then addressing his men he ordered them to leave his cabin.

"We can talk more freely now," he continued affably. "Pray take a seat. The accommodation in this small cabin of mine does not compare with a ward-room or the gun-room of one of His Majesty's battleships, but still I think you will find that chair comfortable."

Hythe sat down. The chair was comfortable enough, but he felt remarkably uncomfortable in spite of the fact that the captain's affability sounded perfectly sincere.

"Do you smoke? Yes? Well, try one of these cigars. I can guarantee them as pure Sumatran."

The sub controlled his amazement with an effort. He had never before heard of smoking in a submarine.

Mechanically he took the proffered cigar, lit it, and waited for the captain to resume the conversation. For his part he was anxious to know what the latter's intentions were regarding his unexpected guest, but something compelled him to await a favourable opportunity.

Captain Restronguet eyed his captive for some moments in silence, then:--

"I am sorry to have to refer to your regrettable failure to take possession of the 'Aphrodite'--that being the name of this craft--but at present the opportunity has not arrived for me to relinquish my command. Perhaps some day----"

The captain paused meditatively. Hythe could see his thick bushy eyebrows narrow till they formed one continuous line.

"Under the circumstances I am compelled to retain you on board for an indefinite time. I trust that you will make yourself as comfortable as you can, and that the wonders of this craft--for wonders they are, although I myself say it--will be sufficiently interesting to prevent ennui."

"But why was I seized by your men, might I ask?"

"You were seized because there was no desirable option. You--I think I am right--you took the initiative by tackling one of my men. They knew perfectly well that three divers were sent down from one of the Government vessels; they had their work to do, and were, of course, loth to be hindered by anyone. Since I gave them particular orders not to do anyone personal injuries, and to maintain a strict neutrality unless molested, they could do nothing else but make you a prisoner. I might also mention that I particularly wished to have a British naval officer with me, for reasons which I hope to explain at some future date. Chance has thrown you across my path, and here you must for the present remain. Your treatment rests with yourself, but please do not regard this as a menace; it is merely a plain statement of facts."

"But you are fairly trapped. You cannot get away!" exclaimed Hythe.

"I think not. At any rate, I will soon find out."

Crossing the cabin Captain Restronguet took up the receiver and mouthpiece of a portable telephone.

"How is the work progressing, Mr. Devoran?" he asked. "All clear? ... Good.... What's that? .... Oh, very well... two hundred revolutions if you wish .... Splendid! ... If you want me I'll be with you ... Thanks!"

The captain replaced the receiver and turned to his guest.

"Perhaps you would like to look through the observation scuttle?" he asked, and touching a switch he extinguished lights and left the cabin in total darkness. Almost immediately after a panel in the flat ceiling of the cabin slid back, rapidly, smoothly, and noiselessly, revealing a rectangular plate of thick glass through which the pale green light streamed, flooding the apartment with subdued hues.

"No need to strain your neck, Mr. Hythe," he exclaimed, as the sub gazed wonderingly at the semi-transparent patch above his head. "Look in front of you; the result from an optical point of view will be just the same, and far more comfortable from an anatomical standpoint."

The young officer did as his host requested. Simultaneously with the sliding back of the panel a mirror hinged at one side had risen from the floor till it attained the angle of forty-five degrees, while another similarly inclined, but face downwards, stood on a table in front of him, and slightly above the level of his head. Thus, by looking into the mirror on the table, Hythe could without inconvenience see everything that could be observed through the observation pane.

He sat there absolutely fascinated. The "Aphrodite" had escaped the coils that had, at the cost of so much labour and time, been thrown about her. She was moving, yet not the faintest vibration or sound came from the propelling machinery. Above were numerous dark objects seemingly in suspension in the pale green vault of water; they were the keels of various vessels, large and small, that had foregathered in Cawsand Bay to witness the capture of the mysterious submarine.

CHAPTER VII.

IN THE CONNING-TOWER.

For several minutes Arnold Hythe sat motionless, watching the rapidly-changing objects that flitted across the inclined mirror. Captain Restronguet made no attempt to distract his attention, but standing with folded arms he watched with feelings of satisfaction the effects of the spectacle upon the young officer's face.

"Wonderful!" exclaimed the sub at length.

"You think so, Mr. Hythe? Let me assure you that this view is nothing to what I can show you. Suppose we take a stroll for'ard?"

The captain opened the door of his cabin.

"You will excuse me preceding you," he remarked apologetically. "We will proceed to the fore conning-tower. Oh, yes, the 'Aphrodite' has two. That accounts for the reports of the master of the 'Barberton Castle,' that he sighted two submarines lying side by side. As a matter of fact he saw the two conning-towers of the 'Aphrodite' against the light, and influenced by the fact that he had hitherto seen submarines with single conning-towers he was misled. Had he really seen two submarines"--and here Captain Restronguet's features darkened ominously--"he would have witnessed a catastrophe to one of them. But of that I will say more later. Suppose we look into this compartment on our way for'ard."

Hythe's guide rolled back a sliding-hatch that communicated with the men's quarters--a fairly spacious room on the starboard side amidships. To the sub's surprise he saw O'Shaunessey.

"Holy St. Pathrick!" ejaculated the seaman, almost forgetting in his excitement to salute. "Faith! sorr, how came you in this shebeen? Sure, I thought 'twas meself only as these rascally foreign spalpeens 'ad taken."

"They collared me too, O'Shaunessey," answered Hythe.

"Bad cess to them!" continued the gigantic Irishman, shaking his fist in the direction of half a dozen almost as powerfully built men who were imperturbably regarding their captive. "They tackled me with some insthrument, an' I couldn't raise me hand in self defence. They must have known that I could never stand being tickled, the ign'rant foreigners."

"Why foreigners, O'Shaunessey?" asked the sub, while Captain Restronguet gave a low chuckle.

"Ain't they foreigners, bedad? I prached to 'em like the blessed St. Pathrick held forth to the sarpints, an' all they did was to shake their heads."

"There is no necessity to keep up this pretence any longer, men," exclaimed Captain Restronguet. "This sailor must be treated as one of yourselves for the time being. You might reassure him, Mr. Hythe, for in spite of our electric treatment he seems inclined to be troublesome, and a good deal of damage might be done if we have to use strong measures."

"Look here, O'Shaunessey," said the sub, "we must make the best of our present position. This gentleman, Captain Restronguet, will doubtless put us ashore in good time," and with a swift look that the sailor rightly interpreted that he must keep his weather eye lifting, Hythe followed the captain out of the compartment.

"This is the for'ard double bulkhead," explained Captain Restronguet, as the pair came to the doors that Hythe had previously noticed. "The 'Aphrodite' is built in three separate sections, any of which can, in a case of emergency, be detached from the remaining portion and still remain watertight. The midship sections at the two principal bulkheads are identical. Thus if the centre compartment should happen to be holed the fore and after sections can be detached, brought together, and secured. We would then still be a submarine of two-thirds the length of the present one. In the foremost section are the offensive appliances, subsidiary motors, and certain stores. The midship portion forms the living space for the crew, main store rooms, etc.; the after section contains the officers' cabins, and underneath them the main propelling machinery. In each section is a diving-chamber capable of being flooded in order to allow the crew to leave the vessel when occasions arise. The exit in the midship section is on Number Two Platform; in the others it is on Number Three."

"Sounds like a railway station," thought Hythe; then--

"What do you mean by platforms?" he asked.

"You might prefer to call them decks, Mr. Hythe. Number One is literally on deck, and extends practically the whole length and breadth of the vessel. Her sections are, as you doubtless have observed, almost square, the ridges of the deck and the bilges being very slightly rounded off. This gives plenty of space for the crew when running on the surface, and also enables the 'Aphrodite' to rest on the bottom of the sea without any perceptible list, unless, of course, the bed shelves at all. Number Two Platform--but perhaps you are not interested?"

"Rather!" exclaimed the young officer eagerly.

"Well, then, Number Two Platform runs fore and aft at nine feet below the overhead girders, so there is no necessity to have to stoop when in any of the compartments or alley-ways. Number Three Platform rests on the cross girders that are bolted to the keelson, and being airtight form a hollow bottom. As a matter of fact these double bottom compartments are nearly always filled with water, which can be ejected by powerful, quick-delivery force pumps when necessary. Here is the door in the base of the for'ard conning-tower."

Unfastening the door by a cam-action lever Captain Restronguet agilely negotiated the narrow way and sprang up a steel ladder. Hythe followed and found himself standing on a metal grating in the company of the captain and a quarter-master. The latter took no notice of his superiors beyond moving a little to one side; his whole attention was fixed upon the task of steering the submerged craft.

The interior of the conning-tower was literally lined with electrical appliances, each switch distinctly marked according to the work it had to perform, but for the moment the sub paid scant heed to them. His eyes travelled in the direction of one of three large oval scuttles filled with plate glass.

The submersion indicator pointed to thirty-four feet, a depth that allowed the "Aphrodite" to pass under the keel of the deepest draughted battleship afloat, with five feet to spare. The compass pointed due east.

"We are just pottering about, as it were, between the Draystone and the Mewstone," announced Captain Restronguet. "The depth here averages ten fathoms, which gives us a margin of five feet under our keel. There is a battleship coming out of harbour, she is now in Smeaton Pass, and we are waiting for her to draw clear. On a falling tide we must take no risks."

"What do you mean?" asked Hythe.

"Simply that as soon as the vessel is outside the Breakwater I mean to take the 'Aphrodite' into the Hamoaze, and give you a chance to see that historic stretch of water under slightly different conditions from that which you have been accustomed to, Mr. Hythe. You were in the submarine service, I believe?"

"Yes," assented the sub. "But how do you know that?"

"Merely by a reference to the Navy List. But look ahead; see that object dead in line with our bows?"

"An electro-contact mine, by Jove!" exclaimed Hythe.

"Right again. Since the beginning of this German war-scare, which I venture to predict will pass away, unless my powers of reasoning play me false, the approaches to all British ports of any magnitude, especially the naval ones, have been strewn with these contrivances. Watch."

A slight touch on the switch controlling the helm and the "Aphrodite" swung away to starboard, clearing the deadly mine by less than twenty feet. Another loomed up ahead, only to be avoided by another touch of the helmsman's finger.

"I do not want to boast," remarked Captain Restronguet, "but I have enough electrical energy stored within this vessel to explode simultaneously every mine, be it a mechanical, observation, or electro-contact one, in Plymouth Sound, and even seriously imperil every fort and ship in the vicinity. Some day I may have to put the powers at my command to a stern test, but until the necessity actually arises I prefer to exploit the 'Aphrodite' solely as an example of what I am capable of producing in the interests of science. Look out of that scuttle on your left; what do you see?"

"A regular pile of huge stones," replied the sub.

"The eastern extremity of that wonderful work known as Plymouth Breakwater. We are now in only forty-five feet of water allowing for the state of the tide. The top of our conning-towers are but fifteen feet above the surface, yet I can assert with confidence that anyone standing on Staddon Heights and looking down upon this channel from an altitude of not less than three hundred and fifty feet would not see the faintest sign of the 'Aphrodite.'"

"What causes her to be almost invisible?" asked Hythe. "Are her plates made of or faced with glass?"

"Oh, no. Glass would not serve the purpose. The light would be reflected too much. In fact the 'Aphrodite' would be a huge heliograph, sending out rays of reflected sunlight in all directions. The composition placed over the steel plating of this submarine is a secret. All I can say at present is that it has the power to reflect the image of near objects only. It absorbs all brilliant rays of light, and is in consequence an almost perfect form of invisibility."

"What is that?" asked Hythe excitedly, pointing to a sudden turmoil in the water ahead.

"Only the action of the triple propellers of a torpedo-boat-destroyer. We are overhauling her. Ease down to ten knots, Carnon. She's off through the Asia Pass. There's not enough water for us; so let her come round to starboard."

The quartermaster telegraphed for speed to be reduced; the submarine turned towards the deeper Smeaton Pass, leaving the destroyer, in blissful ignorance of the proximity of the much-searched-for Captain Restronguet, to take the short cut into the Hamoaze.

"Now we can take things more easily," observed the captain after awhile. "The channel is now ninety feet deep, although we are but a few hundred yards from Plymouth Hoe. We are now approaching the Drake Channel, between the Victualling Yard and Drake's Island."

"However do you contrive to find your way about in a complicated waterway like this?" asked the sub, who was well acquainted with the above water navigation of that part of Plymouth Sound within the Breakwater. "You have no periscope?"

"A periscope would soon give the show away," observed his companion. "For the present, we simply rely upon the chart and compass, and look out for the sudden shelving of the bottom. See, there! Hard a starboard, quartermaster: there's the Vanguard Bank dead ahead."

From almost due south the "lubber's line" in the compass-bowl pointed to almost due north. The "Aphrodite" had reached the "Narrows" between the Devil's Point and Cremyll.

At a word from Captain Restronguet the quartermaster set the engine room telegraph indicator to stop; another movement, a gentle hiss betokened the admittance of water into one of the sub-compartments of the vessel. Then slowly and mysteriously the "Aphrodite" sank in twenty-two fathoms of water to the bed of the narrow channel.

At that depth, and owing to the swift-running tide, charged with the mud brought down by the River Tamar, the water was so thick that, till the electric lamps were switched on, the submarine was in total darkness.

"Prepare to anchor," ordered Captain Restronguet through a telephone.

"Good!" he ejaculated, after about a minute had elapsed. "Now, Mr. Hythe, you must be feeling hungry; so will you do me the honour of having lunch in my cabin?"

CHAPTER VIII.

EXPLANATIONS.

"By the by," observed Captain Restronguet, as he entered the cabin, "I have already sent a reassuring message concerning you to the British Admiralty."

"You have! How?" asked Hythe in astonishment. "You are not fitted with wireless?"

"And why not? As a matter of fact we are; with one of the latest type of Raldorf-Holperfeld instruments, which, as you know, do not require out-board aerials. The message is received by an automatic recorder."

"And, might I ask, with whom do you communicate?"

"That need not be kept a secret from you, Mr. Hythe."

"Why not, sir?"

"Because I wish to detain you on board the 'Aphrodite' until I have no further use for secret correspondents. My wish is law, Mr. Hythe, and please to remember that. At the same time I wish to make your period of enforced detention pass as pleasantly as possible, and you will have complete facilities, up to a certain point, of gaining valuable information that will in time to come amply recompense you for any slight inconvenience that might arise."

"But my career? Remember, sir, I'm a naval officer."

"Of course. That is one reason why I think fit to keep you. Had you been an ordinary or even an able seaman, I should have taken the first opportunity of putting you ashore, with hardly any chance of your seeing anything on board the vessel that might be put to my disadvantage. As soon as I learned that you were a naval sub-lieutenant I made up my mind to retain you as my guest for awhile."

"Then you are going to release O'Shaunessey?"

"Not at present. He, too, will serve a good purpose. He will be able to corroborate my statement that you will be honourably treated."

"But that will be unnecessary. Surely my word----"

"I have every confidence in the word of an officer and a gentleman, Mr. Hythe. But my proposals are rarely influenced by circumstances other than the workings of Providence. You asked me a question concerning my shore agents. The answer is this: so long as the Government bestows licences upon private individuals to dabble in wireless telegraphy experiments it is a simple matter to keep in touch with events ashore. My principal agent lives in Highgate. He is a skilled operator, but he has contrived to keep his capabilities masked under the role of a harmless amateur. By advancing or retarding the spark of the powerful coil of his instrument he can 'tap' any messages, whether from British or foreign warships, within seven hundred miles, while on occasions he has accurately read messages from Cape Race. Of course, most of the naval messages are in code, and are unintelligible to the uninitiated. Nevertheless I can learn all outside news from this particular agent even when in the Mediterranean. For short distances we make use of wireless telephony, and by this means I can communicate with trusty agents in Devonport, Portsmouth, Sheet-ness and Chatham, and under certain circumstances with Rosyth and Dundee."

"Why did you come to a standstill here?" asked the sub.

"To partially recharge our accumulators. Our motive power is electricity. My invention in that direction is a revolution in marine and submarine propulsion. We are now anchored."

"Anchored?" echoed Hythe. "How? I saw no anchors when I examined your vessel from the outside."

"Anchoring, as we understand the term, consists of allowing the 'Aphrodite' to settle on the bottom of the sea. By lowering four steel plates, inclined at an angle of forty-five degrees--the acute angle facing aft--an almost irresistible brake, something after the principle of the spade recoil brake of the French quick-firing field guns, is formed. At this moment the ebb tide is swirling past at four knots. The force of the current is turning our propellers, which, acting for the time being on subsidiary shafting, drive the dynamos that in turn replenish our accumulators."

"Then that means that every day you must recharge? How do you manage when there is not sufficient tide to actuate the propellers?"

"My dear sir," replied Captain Restronguet, "I ought to have said that we were partially replenishing our reserve of electricity. At this moment there is sufficient power on board to drive the 'Aphrodite' at a speed of thirty-five knots on the surface or twenty when submerged, for a continuous period of at least one hundred and twenty hours. We merely take advantage of the opportunity to increase our reserve. But you are not eating. Is my meagre fare not sufficiently tempting?"

"I am too interested to think about eating," replied Hythe. "But now you mention it I feel quite peckish."

"We are obliged to do without fresh meat," said Captain Restronguet apologetically. "Nevertheless I think you will find this dish of pilchards excellent. Here is seakale sauce that by the skill of the 'Aphrodite's' cook can hardly be distinguished from asparagus. Roast dog-fish, if you care to try it, you will find hard to believe anything but beef-steak. By a certain process, simple to apply, all taste of fish is eliminated."

Captain Restronguet helped his guest to a slice of dog-fish--a fish that fishermen not so many years back generally threw back into the sea as useless.

"Excellent," declared the sub. "However is this dish produced in this guise?"

"Also by electricity," said Captain Restronguet calmly. "By applying a certain form of current all the oily portions of the fish are destroyed, leaving only the red corpuscles in the flesh."

Just then came a knock at the door, and in response to the captain's permission to enter one of the crew appeared, holding an envelope in his hand.

"H'm! Message from the wireless room--excuse me," remarked Captain Restronguet, as he began to tear open the flap. "Shouldn't be surprised, Mr. Hythe, if this doesn't concern you. Yes, listen: 'Secretary of Admiralty acknowledges Captain Restronguet's message re safety of Sub-Lieutenant Arnold Hythe and Michael O'Shaunessey, A.B. If genuine a message from the naval officer detained is requested. Reasons are also desired why Captain Restronguet took forcible possession of two of His Majesty's subjects.' Ha! That is a reasonable message."

"Reasonable?"

"Yes. The Admiralty are beginning to realize that I, Captain Restronguet, am a person worthy of their consideration. That is more than they did a few years' back. As a matter of fact I have had a little quarrel with My Lords. Some day I will give you details; but meanwhile I am continuing my harmless yet disconcerting tactics that tend to prove how futile the defences of this country are against the latest product of modern science. Yes, Mr. Hythe, the Secretary of the Admiralty will have definite evidence before many hours have passed."

*      *      *      *      *

To go back to H.M.S. "Investigator": as soon as Hythe's appeal for help was received the attendants on the diving-party began to haul in the sub's life-line, but before five fathoms had been brought inboard a sudden relaxation of the strain told them that the rope had been severed.

"Be sharp, men! Blow him to the surface," ordered Egmont. "There's something up down there."

"Mr. Hythe's just signalled for more air, sir," announced the seaman who had charge of the telephone.

Rapidly the handles of the air-pump revolved. An increase in the number and size of the bubbles rising to the surface was the only result.

"See if the others are all right," ordered the lieutenant. "What's that? O'Shaunessey reports all correct; tell him to find out what's wrong with Mr. Hythe. Can't you get any reply from Mr. Hythe, Mr. Smithers?"

"No reply, sir," said the man laconically.

A paying out of the Irishman's life-line told them on deck that O'Shaunessey was on his way to look for his officer. Five minutes elapsed, then a confused jumble of ejaculations through the telephone betokened the unmistakable fact that the Hibernian diver was shouting at the top of his voice.

"Stow it, mate; what's the bloomin' use of shoutin' like that?" spoke the man on O'Shaunessey's telephone reprovingly. Then, after a short interval, he took the instrument from his ear and turned to Lieutenant Egmont.

"Wire's cut off, sir," he announced.

"And his life-line and air-tube cut, too, sir," added another seaman.

"Great heavens! what's up?" ejaculated the lieutenant. "Here, bring Price up before he's done for."

Hastily Egmont communicated this disquieting news to Captain Tarfag. The latter went for'ard and awaited Diver Price's re-appearance.

As soon as Price's helmet appeared above the surface his glass plate was unscrewed, revealing his features as pale as a sheet.

"What has happened?" demanded Captain Tarfag anxiously.

The man was incapable of speech. He could only raise one hand in a gesture of horror and despair.

"Help him over the side, men," ordered the captain. "Run aft, one of you, and ask the steward to give you a stiff glass of grog."

Quickly Price was divested of his helmet and dress. Shaking like a leaf he sat down upon a bollard. He drained the glass of whisky at one gulp, and the colour began to return to his face.

"Both done for!" he cried. "Saw my mate stabbed by the villains. Never caught a sight o' Mr. Hythe."

"By heavens, I'll not stand this!" thundered Captain Tarfag. "I want three men to go down--who will volunteer?"

"I will, sir!" came a chorus of voices. Every man qualified as a diver had offered to risk possibly certain death in the depths of the sea.

"You three," ordered the captain, indicating Moy, Banks, and Smithers. "Keep your knives in your hands and don't hesitate to use them. Take a charge of guncotton. If you've a chance place it under her bilges, and I'll take the risk of blowing this infernal submarine to Jericho."

Quickly the three dauntless divers prepared to descend, while a petty officer and two seamen hastened to bring the explosive from the magazine and the batteries for firing the charge.

But ere the divers were ready a sudden commotion on shore attracted the attention of Captain Tarfag and the crew of the "Investigator." The working party on the beach had discovered that the net entanglements no longer held. They were coming home with hardly any resistance, bringing with them the grapnels of the picquet-boats till the latter had to hastily cast off in order to prevent themselves being dragged ashore.

"She's given us the slip, by George!" ejaculated Mr. Egmont.

"Perhaps the nets have parted," suggested Captain Tarfag. "Look alive, men!"

One after another the divers disappeared over the side. Three distinct patches of bubbles indicated their course. They were, for mutual safety, keeping close together. To all inquiries on the telephone the answer was, "Nothing to be seen," until Moy reported that he had discovered distinct traces in the sand of the impression of a fairly flat-bottomed vessel of at least thirty foot beam.

"It's no go," exclaimed Captain Tarfag. "Order the men back, and report the loss of Mr. Hythe and O' Shaunessey to the Commander-in-Chief at Devonport. By smoke! All the fat is in the fire now."

Quickly the dispiriting news spread from ship to ship, and from boat to boat. A panic seemed to seize the spectators in private craft, for, as if by a sudden impulse, they made a wild stampede from the shelter of the shallow water of Cawsand Bay. But nothing happened to imperil their safety. No huge sea-monster, the work of human hands, appeared to scatter destruction broadcast upon those venturesome individuals who had gone forth to witness the capture of the mysterious Captain Restronguet. The elusive submarine had calmly stolen away, without a trace of the tragedy that every one imagined had been enacted beneath the waves, save for portions of the two life-lines and the disconnected air-tubes.

The "Investigator" and the rest of the Government vessels lost no time in putting into the Hamoaze. Captain Tarfag, accompanied by Lieutenant Egmont, immediately went on shore to report to the Commander-in-Chief. Already special editions of the papers were out, giving more or less accurate accounts of the futile operations in connexion with the attempt to capture the submarine, and all laid particular stress upon the fact that the lives of an officer and a seaman had been sacrificed on the altar of duty.

"You saw nothing, Tarfag?" asked the Admiral.

"Nothing, sir. The diver who escaped reported that the whole time he was below he saw no trace of the submarine, although he followed the line of netting for several yards. What he did see was his comrade, O'Shaunessey, beset by half a dozen men. He admitted he was terribly scared, but went to his fellow-diver's assistance. Before he could get close enough he saw that O'Shaunessey's life-line had been cut and his air-tube disconnected. Realizing that he could do nothing, and that he was in pressing danger, Price signalled to be hauled up."

"But how did the submarine contrive to get clear of the wire and rope entanglements? Surely you saw some signs of a commotion?"

"Nothing--not even a ripple. The first intimation we had was from the shore. The nets came home quite easily."

"H'm," ejaculated the Admiral. "Perhaps I----"

The entrance of an assistant secretary caused the Commander-in-Chief to pause abruptly. The newcomer held out a type-written document.

"Message through from the Admiralty, sir," he announced.

"By Jove! What's this?" exclaimed the astonished Admiral. "The Secretary to the Admiralty reports that a telephone message was received from a North London call-office, reporting that Mr. Hythe and O' Shaunessey are prisoners on the submarine. Furthermore, a telegram from Dantzic announces that Captain Restronguet--confound that fellow!--has destroyed the armoured cruiser 'Breslau.'"

"When was that, sir?" asked Captain Tarfag.

"The message from Dantzic is dated 8 a.m. this morning. Allowing for differences in Greenwich time----"

"Then, if the submarine we were after is under the command of Captain Restronguet, it is morally impossible for him to be in the Baltic at precisely the same hour----"

"Unless there are two of these blessed submarines."

"Or two captains of the name of Restronguet," added Captain Tarfag.

"I suppose this fellow means to hold Mr. Hythe to ransom, sir?" asked Mr. Egmont.

"There is no mention of that," replied the Admiral. "But, of course, that may be his intention. I wonder where the mysterious submarine will turn up next?"

"The Superintendent of Police, sir," announced the head-messenger.

"Ah, Richardson, what's the trouble now?" asked the Commander-in-Chief, as a tall, alert-looking man stepped briskly into the room.

"More evidence of Captain Restronguet, sir," replied the Superintendent of Police. "The rascal's actually in the Hamoaze. Our duty boat, whilst returning from Bull Point, picked up a green and white buoy, just abreast of Wilcove. Attached to the buoy, and protected by a water-proof covering, was this document."

The admiral took the paper--a foolscap sheet, with a crest and the words "Submarine 'Aphrodite'" embossed upon it. In silence he read it to the end, then--

"Well, of all the most confounded cheek!" he ejaculated. "Read that, Tarfag, and tell me what you think of it."

"I have the honour to acknowledge the receipt of the Admiralty's message of even date. In order to prove conclusively that this reply is authentic, I have taken steps to see that this document is placed in the hands of the Commander-in-Chief of the Devonport Command. Mr. Arnold Hythe and A.B. O'Shaunessey, official number K14,027, are on board my vessel 'Aphrodite.' In the interests of the Service, and also in my own, it is desirable that Mr. Hythe remain on board for a period not exceeding six months. Any information the officer in question may gain is entirely at the disposal of the British Admiralty, and since the possibilities of so doing are great, I would suggest that covering permission be given for Mr. Hythe's absence from his official duties. Incidentally I may mention that this suggested permission is merely formal, for in any case my guests will not be put ashore until I think fit.

"I am at present giving a series of demonstrations in British waters, but not with any aggressive intent. It is hopeless to attempt the capture of my submarine, and no useful purpose will be thereby served.

"I take this opportunity of explaining the cause of the hostile acts committed against an outwardly friendly State, in the hope that the calamity of a great war may be averted.

"The submarine in Baltic waters is the property of Karl von Harburg, a German renegade, who has certain motives in committing these excesses, which can neither be justifiable nor excusable. His submarine, itself a craft of great abilities, is but a feeble imitation of my 'Aphrodite.' It will not help matters to any great extent by explaining my reasons, but I can assure you that at the first available opportunity I mean to destroy the submarine owned and commanded by Karl von Harburg, as I regard the man as an unprincipled international scoundrel and a scourge to humanity.

"Will you kindly forward this document to the Secretary of the Admiralty, and inform him that my agent will receive his reply per telephone, at the hour of 10 a.m. to-morrow.

"I have the honour to be, Sir,
"Yours, etc.,

"JOHN RESTRONGUET."

CHAPTER IX.

THE FIRST DAY IN THE "APHRODITE."

A bell rang out sharply in the captain's cabin of the "Aphrodite," and one of the electric indicators oscillated rapidly.

"Accumulators charged," announced Captain Restronguet laconically.

"It is a revelation to me," said Hythe. "And when one comes to consider that at every hour of the day hundreds, nay thousands, of ships are straining idly at their moorings, it is certainly remarkable that no satisfactory attempt has hitherto been made to harness the tides."

"That's only one of the many lessons you will learn," remarked the Captain. "But we are getting under way once more. Perhaps you would like to see the mechanism on Number Three Platform?"

"Most certainly I should," replied the sub.

In the alley-way they encountered a short, broad-shouldered man who had to set his back against the metal wall in order to allow his captain to pass.

"All correct, sir," he said saluting.

"Right, Mr. Devoran. Who's in the conning-tower?"

"Mylor, sir."

"Good. I will take the 'Aphrodite' up the river. You need not turn out till midnight. I shall want you then."

"That is my chief mate, Mr. Devoran," remarked Captain Restronguet, after the man had gone to his cabin. "A truer-hearted comrade one could not possibly desire. He is the only man on board beside myself who thoroughly understands the whole of the complicated mechanism of my masterpiece. There are others who are capable of manoeuvring the 'Aphrodite,' but they do not understand how to handle her for offensive purposes."

Throwing back a watertight sliding-door in the port fore and aft bulkhead Captain Restronguet signed to the sub to enter. Hythe found himself in a small compartment on the walls of which were several articles and gear. No space was wasted on board the "Aphrodite."

In the centre of the floor was an oval-shaped aperture, sealed with a rubber-lined lid, that by means of double levers could be opened from either above or below. As the hatch opened Hythe saw a portion of the well-lighted interior of the lower deck, access to which being gained by means of a vertical steel ladder.

The for'ard compartment, extending the whole length and breadth of the foremost section of the submarine, with the exception of the space taken up by the diving-exit, was as far unlike the forehold of a ship as the sub could possibly imagine. The cement-cased walls were distempered a pale green; thick corticene--a kind of linoleum used in the Navy--covered the floors; alongside the after bulkhead were two arms-racks filled with automatic rifles and pistols, and other modern small-arms. Secured to the deck was an automatic one-pounder field-gun. Towards the bows were two long narrow tubes, the external diameter by less than seven inches, while a seemingly complicated arrangement of double-locking doors, electric wires, trippers and gauges suggested to the sub that these instruments were torpedo tubes.

"Quite right," said Captain Restronguet in reply to Hythe's question. "A pair of six-inch tubes firing electrically directed torpedoes. They will never miss their target, I can assure you, even at five miles range, if controlled from a lofty station. Here we are limited, but so long as we can see our target by means of our flexibly attached periscope, there is a million chances to one on the weapon striking the mark. But listen!"

The hiss of a powerful water jet was just audible through the double plating of the submarine's hull.

"Merely a precautionary measure to clear the holding plates of mud and seaweed," explained Captain Restronguet. "If the spades, as I might term them, do not fold absolutely flush with the vessel's bottom, there's bound to be a tremendous resistance to the water and consequently a serious loss of speed. Now the jet is turned off. Listen again and you will hear the anchor plates come home."

"That they are!" exclaimed the sub, as a distinct thud shook the plates under his feet. "I suppose they are lifted by metal rods working in water-tight glands?"

"Oh, no; merely by the attraction of electromagnets. Every valve and door in this vessel is electrically controlled, although in some cases, such for instance the hatch by which we gained this compartment, manual power can be used. When next an opportunity serves I will show you the engine-room, but we are about to rise now. I must go to the for'ard conning-tower. You may come, too, if you feel inclined, or if you prefer there is a private cabin at your disposal."

"How does the submarine rise, might I ask? By means of horizontal rudders?"

"Yes and no," replied Captain Restronguet. "But before I explain perhaps this might interest you."

Stepping over to where three levers stood in the centre of the compartment the captain thrust one hard down. Instantly a portion of the floor opened. Another lever caused a corresponding part of the outer plating to slide back, revealing an observation plate of about three feet by two through the double skins of the starboard bilge-plates.

"I can see nothing," said Hythe, as he strove to peer through the glass. "It is perfectly dark."

"There ought to be sufficient light at this depth to see fairly well, but since the 'Aphrodite' is still on or nearly on the bottom of The Narrows, the hull intercepts what little light there is to penetrate the water. Now look!"

Touching a switch Captain Restronguet caused a strong search-light to shine vertically downwards. About a fathom of water lay between her keel and the floor of the sea. She was slowly moving under the influence of the young flood tide. The bed was shelving steeply from one hundred and twenty feet to less than ninety. Hythe could see the seaweed waving in the current and the fash, mostly of the flat-fish tribe, darting rapidly towards the dazzling light.

"What's that?" he asked, as two objects, resembling barnacle-covered pipes passed slowly across the field of light.

"Telephone cables between the Victualling Yard and Mount Edgcumbe," replied his companion. "If I felt inclined, what is to prevent me from sending out a man and tapping those wires? All submarine cables are entirely at my mercy. If I wished I could create a greater panic than the Stock Exchange, the Bourse, or Wall Street ever yet experienced. But I must switch off the light and close the panels now. I am wanted in the conning-tower."

As the sub followed his companion he could not help noticing the freshness of the atmosphere. Compared with the nauseating reek of the submarines he had served in the interior of the "Aphrodite" was as wholesome as could be. There was, moreover, a sting in the atmosphere that recalled the health-giving breezes of the Scottish moors.

"All right, Mylor, you carry on," exclaimed the captain to the helmsman in the conning-tower. "Starboard your helm a bit--go!"

Forty feet beneath the surface the submarine swung round the sharp band formed by the high ground of Cremyll and Mount Edgcumbe. Close to the heavy mooring-chains to the south of the Rubble Bank she glided, till her course, almost due north, lay right up the land-locked Hamoaze.

"Why, we're going up the River Tamar!" exclaimed Hythe, glancing at the compass. His knowledge of the intricacies of Plymouth Harbour and the Hamoaze, and the compass course told him that, for nothing was to be seen through the conning-tower scuttles save an expanse of pale green water.

"Yes, that is so. I am just running up to Saltash in order to pick up a man returning from leave," replied Captain Restronguet with a laugh. He spoke as casually as if he were the coxswain of a British battleship's liberty-boat. "We are now passing the South Yard of Devonport Dockyard. But excuse me, I have something to attend to in the after conning-tower. You won't mind remaining here, I trust? Keep her as she is, Mylor; I am going to reduce speed to five knots or even less."

Hythe sat down on a folding seat fixed below the port scuttle, whence he could see either ahead or on his left. The helmsman's head and shoulders obstructed the view to starboard.

It was fascinating work watching the sea swirl past, and noting the changes as the "Aphrodite" passed through patches of various coloured water, for the tide was beginning to stir up the dark brown sediment brought down from the Devonian Hills by the swift-running Tamar, and the result was a constant kaleidoscope. But after a while, finding that nothing else was visible, the sub transferred his attention to the interior of the conning-tower.

Presently a bell gave forth a warning note and the helmsman promptly touched a lever. The depth according to the gauge diminished to less than thirty-five feet.

"Is that an automatic sounding machine?" asked Hythe.

Mylor, still keeping his eyes fixed in front of him, shut his lips tightly, and Hythe, thinking that he had not caught what had been said, repeated the question.

"Cannot say, sir," said the helmsman decidedly. "It's against orders. For any information ask the cap'n."

"That's a staggerer," thought the sub. "One thing about it the fellow's true to his master."

Meanwhile Captain Restronguet had retired to his cabin, where he drafted a communication to the Commander-in Chief of the Devonport Command. This done, he ascended to the after conning-tower where two seamen were on duty.

"Ship the periscope, Carclew. Directly you sight any small Government craft bearing down this way let me know. And Gwennap, get this letter ready for delivery."

The periscope consisted of a double-wedge shaped instrument connected to the top of the after conning-tower by means of a flexible armoured insulated wire. Carclew, by switching off the current from an electro-magnet, allowed the float to rise to the surface, where, owing to the comparatively slow rate of the submarine, it was towed without being dragged under. As soon as this was done another switch was manipulated, and instantly a reproduction of the surrounding objects was faithfully projected by an advanced form of telephotography upon a dull white board fixed to the wall of the conning-tower.

"There's a black pinnace with a yellow awning coming down stream, sir," announced Carclew. "She's got the letters M.P. on her bows."

"Police launch evidently," said Captain Restronguet. "Now Gwennap, stand by. Are we right under her course, Carclew?"

The man Gwennap had meanwhile placed the document in an oiled covering which in turn he lashed to a globular white and green buoy. This he placed in an ejector, made on the principle of a submerged torpedo tube.

"All ready, sir," he announced.

Captain Restronguet held up his hand, and receiving an affirmative gesture from the seaman at the periscope-board, nodded his head. There was a slight, almost inaudible hiss and the buoy with the message attached, was ejected out of the conning-tower, rising to the surface within fifty yards of the on-coming launch.

"They've picked it up, sir," declared Carclew, after half a minute had elapsed.

"That's well," murmured the captain, as he descended the conning-tower ladder. "I wonder if the reply will be in a similar strain to the one I received five years ago. Ah! I wonder."

And with a grave smile on his resolute features Captain Restronguet returned to his cabin.

"Send Mr. Hythe to me," he ordered, when a seaman appeared in answer to his summons. "And tell the diving-party detailed for duty to have the boat ready for launching; warn Polglaze and Lancarrow to stand by at eleven to-night."

"Now, Mr. Hythe," said Captain Restronguet, when the sub was shown into the cabin, "I may as well tell you that I have reported your presence and that of the able seaman to the Commander-in-Chief, and doubtless I shall have a reply before noon to-morrow. If you would like to see our periscope in working order now is a good opportunity. We are travelling dead slow, and there is plenty to be seen here--more so than at sea."

"It is a picture," exclaimed the sub enthusiastically, as he gazed upon the electrically-depicted panorama. "The whole horizon is included; but how do you know in what direction an object is lying?"

"Simply by the position of this board. It revolves by the same magnetic influence that causes the compass card always to point to the magnetic-north, only here we have made corrections for the variation of the compass. The only drawback is that objects to the south are shown inverted on the board, but with a little practice one soon gets accustomed to this. It is like the inverted image on the ground glass of a camera, and to an experienced photographer that state of affairs presents no difficulty. Here we are: right abeam on the starboard hand you can see Bull Point, the ordnance depot. When were you last up the river Tamar, might I ask?"

"Quite two years ago."

"And it is more than seven since last I saw Saltash Bridge. There have been vast changes, and I suppose had you been at the periscope all the way up the Hamoaze you would have noticed a difference in the aspect of the place."

"I see that they've covered in the magazines with earth," said Hythe. "That's for protection against attack from aerial craft."

"And it is the same in Devonport and Keyham Yards. There's no doubt the British nation has developed an air-invasion panic. For instance: years ago all the building slips in the Royal Dockyards were roofed in. I can remember the huge sloping roofs with their skylights arranged after the manner of the ports of an old three-decker man-of-war. Early in the present century these roofs were removed, and the slips were left entirely open and uncovered. Now what do I see? Every dock, every slip, every Government workshop of importance is housed in with a bomb-proof steel roof. And with one touch of my little finger I could do more damage, and without being seen, to that place yonder than the combined aerial fleets of Germany and Austria. But see, we are in sight of Saltash Bridge. Just below that structure I mean to bring up for the night. I regret, Mr. Hythe, I cannot give you an opportunity to stretch your legs upon Devon or Cornish soil, but I trust that you will realize that circumstances prevent my so doing."

The "Aphrodite" sank to the bed of the river between the lofty bridge and the chains of the floating-bridge plying between the village of Saltash and the left bank of the Tamar. Here in fifty-six feet of water she was in absolute safety, and since there was no occasion to recharge her accumulators, she had chosen a berth where she was partially protected from the full force of the tide by water-pipes that are laid across the bed of the river by the side of the Albert Bridge.

Just before dinner Hythe asked if he could see his man, O'Shaunessey, and to this request Captain Restronguet made no objection. The sub could, of course, have had the Irishman sent to the cabin allotted to his personal use, but somehow he preferred to see the man in the crew's quarters. With so many mechanical and electrical contrivances about her Hythe fought shy of conversing with O'Shaunessey in his cabin; there might, he thought, be some device whereby the captain could overhear every word.

The men's living-room presented quite an animated scene when Hythe entered. Tea had just been finished, and the crew who were on "watch below" were playing cards, dominoes, and billiards, or else reading or talking. A large electric gramophone was reproducing the latest songs, interspersed with the old-time seamen's chanties that seemed utterly out of place within a submarine. Captain Restronguet, recognizing the demoralizing effect of ennui, had taken every safeguard to maintain a cheerful demeanour amongst his men.

Although nearly every one was smoking there was hardly any sign of fumes. Overhead three electric fans were expelling the smoke, but how the vapour was ejected from the vessel Hythe could not imagine.

O'Shaunessey was sitting at a table, eagerly conversing with two of the crew. The Irishman's sense of humour appealed to his new comrades, and with an adaptability that contrasted forcibly with his belligerent attitude earlier in the day, O'Shaunessey was cracking jokes right and left.

As the young officer entered, the crew stood up--not with the alacrity of naval men, but all the same with a sense of respect towards their superiors in rank.

"Carry on, men," exclaimed Hythe, and crossing over to where O'Shaunessey stood he asked him how he fared.

"Sure, an' I've fallen on me fate this time, sorr," replied the Irishman with a grin. "They are feeding me up like O'Leary's pig, an' it's a drap o' the old cratur they serve out at eight bells, which is more to me loikin' than navy rum--after the steward's wathered it."

The men to whom O'Shaunessey had been talking smiled broadly at this, and considerately moved away so that the sub and the seaman could converse in private. Hythe was beginning to be afraid that the Irishman was too contented to make an effort to obtain his liberty should occasion arise; but lowering his voice O'Shaunessey continued,

"All the same, sorr, it's to be back aboard the 'Investigator' that I'm wanting. 'Ave you any idea wan they'll let us out o' this?"

"Not in the least, O'Shaunessey. Nevertheless we must try to get clear as soon as possible, unless I receive definite orders to the contrary."

"Definite orders to the contrary, sorr? From where, may Oi make so bold as to ask?"

In a few words the sub imparted the information that news of their presence within the submarine had been sent to the Admiralty.

"St. Pathrick and the rest of the Saints be prised, sorr!" exclaimed O'Shaunessey fervently. "Sure, 'tis a load off me mind, for 'tis me ould mother in Ballydonfin, County Wexford, that might be lamentin' for her only son."

"They haven't asked you to join the crew?"

"Bad luck be on their heads if they did, by Jabers!" ejaculated the Irishman. "Sure, I'm thrue to me salt."

"Ssh," muttered Hythe warningly, then in a louder tone he added, "Well, I am pleased to learn that you are being well looked after, O'Shaunessey. I'll look in again soon, and see how you are getting on."

On returning to the captain's cabin Hythe found that dinner was about to be served, and Captain Restronguet and Devoran, the chief officer, were in evening dress.

"I am sorry I had no opportunity of bringing my mess-jacket," said the sub, half-humorously, half-apologetically. "But you see I came on short notice."

"Don't let that trouble you, Mr. Hythe," replied Captain Restronguet. "As a matter of fact, we invariably make it a practice of dressing for dinner. It recalls old times, doesn't it, Devoran?"

"Rather," replied the chief officer. Hythe noticed that for the time being all traces of differences in rank were set aside. Captain Restronguet and Mr. Devoran were more like staunch friends than superior and subordinate officers; but on all other occasions the latter's attitude was strictly conformable to etiquette afloat.

The dinner passed pleasantly. The three men, by an unspoken yet mutual consent, studiously avoided "shop," their conversation dwelling on ordinary every-day topics. All the same Hythe could not help noticing how conversant they both were with the latest plays, books, and the events that afford interest to the Man-about-Town.

After dinner Devoran left the cabin. The captain busied himself with writing, while Hythe, selecting a book from a small library, and lighting a cigar, sought the comfort of an easy chair.

For an hour Captain Restronguet wrote steadily. He seemed quite indifferent to his guest's presence. Presently the sub found himself nodding over the book. He had been up early, and had had a trying and exciting day.

"What, nearly asleep!" exclaimed Captain Restronguet, as he set aside his papers and writing material. "But I forgot; you must be tired. Your bed is quite ready, so you can retire as soon as you wish."

Nothing loth Hythe bade his host good-night, and ten minutes later he was sound asleep in a comfortable bunk, ten fathoms beneath the surface of the River Tamar.

CHAPTER X.

THE SECOND OFFICER RETURNS.

Captain Restronguet remained in his cabin till nearly ten o'clock, then, going into an adjoining dressing-room, he changed into his "duty clothes," donned a thick coat and india-rubber boots, and made his way for'ard to the diving-room in the fore compartment.

Here the men had unshipped the collapsible boat, but as yet it had not been unfolded.

"Are you going to bring her to the surface, sir?" asked Polglaze, seeing that his captain was in his great coat.

"Yes, I have decided to do so," replied Captain Restronguet. "Bring the boat under the upper hatchway, Lancarrow, and you, Gwennap, I want you to lay out a kedge up stream. See that the flukes engage in the rubble-work in the base of the centre-pier of the bridge, and run out another kedge aft."

Lancarrow and Gwennap promptly donned their diving suits and entered the "water-lock," taking with them the anchors and a length of stout Manila rope. Twenty minutes later they returned, the water dripping from their glistening garb.

"All correct, sir," reported Lancarrow, as soon as his headdress was removed. "Nothing short of the rope parting will set us adrift, and there's precious little tide running now. I took good care to ram the fluke of the kedges well home."

"What is it like up above--dark?"

"I went up to have a look round, sir," announced Gwennap. "It is a pitch-dark night, the stars are in, and there's hardly a breath of wind."

"Good!" exclaimed Captain Restronguet approvingly. "Pass the word to Mr. Devoran to bring the vessel awash."

The water in two of the buoyancy tanks was quickly expelled, and majestically the huge submerged hull rose from the bed of the river, till with her deck just a few inches above the surface she fretted gently at her mooring-rope.

Being immediately below the massive pier of the Tubular Bridge there was no danger of a passing vessel--should one be under way at that hour--colliding with the "Aphrodite"; while owing to the darkness and the light-absorbing powers of her hull she was absolutely invisible at a boat's length off.

Rapidly yet silently the hatch on deck was unfastened and slid back. The collapsible boat, weighing less than sixty pounds, was passed through, extended, and kept in position by means of stretchers.

Carclew and Gwennap tossed the oars into the frail craft, and holding the painter launched her over the side.

"Ready, sir," whispered the latter.

Captain Restronguet immediately came on deck and stepped agilely into the boat; the bowman pushed off, the oars dipped, and the canvas cockleshell darted in the direction of Coombe Bay, a tidal indentation just south of the town of Saltash.

"Thank goodness it is a fairly black night," muttered Captain Restronguet. Beyond the pontoon lights at Saltash, the signal lamps of the railway, and the riding lights of a few vessels lying at the buoys on the west side of the river, all was in darkness. To gain the entrance to Coombe Bay it was necessary to pass between two cruisers, whose anchor lamps glimmered fitfully, throwing scintillating reflections on the placid water.

"Boat ahoy!" challenged the look-out on the nearest vessel.

The captain of the "Aphrodite" was equal to the occasion.

"Passing!" he roared, using the shibboleth laid down in the Naval Regulations for this contingency.

This reply apparently satisfied the look-out, and without further interruption the canvas boat drew into the shallow waters of Coombe Bay. Fortunately the tide was nearly at the full, and still rising, and hence no danger of being stranded on the mud was likely to occur.

"Easy, men," cautioned Captain Restronguet, as the gaunt outlines of the railway bridge spanning the creek loomed up against the darkness. Then, "Lay on your oars."

Gradually losing way the boat drifted on till it grounded on the shingle hard at the foot of the bridge. The boat's crew listened intently; beyond the distant rumble of a belated train, and the faint hoot of a liner's syren away out in the Sound, all was still.

Ten minutes passed. Captain Restronguet knitted his brows in perplexity.

"There's some one, sir," whispered Gwennap, as the cautious scrunching of a man's boots upon the shingle could be faintly heard. Then a dark figure appeared out of the night.

"Is that you, Kenwyn?" demanded the Captain in a low voice.

"Ay, ay, sir."

"Then jump in; I thought you had missed us."

"Couldn't get here any sooner, sir," said the man apologetically. "I was stopped and questioned by a patrol as I came down from the station. There are launches up and down the river, I am told, looking for us."

"The deuce there are!" exclaimed Captain Restronguet; then in a calmer tone he added, "We must risk it. Perhaps it is my fault; but I don't think they'll look for the 'Aphrodite' so close to the bridge. Give way, men."

On gaining the main stream, greatly to the relief of all in the boat, no red and green lights of patrolling launches were to be seen. Boldly Captain Restronguet steered across the bows of the cruiser that had hailed him on the outward trip. To lurk inshore would be courting suspicion.

"Boat ahoy!" came the hail from the lookout.

Captain Restronguet replied as before, but this time the look-out was not satisfied.

"What boat is that?" he shouted.

"Customs!" roared the captain with a lucky inspiration.

Muttering a malediction on all custom-house officials, especially on those in this particular boat, the seaman resumed his walk up and down the fo'c'sle deck. He remembered a certain half a pound of tobacco that had got him into trouble with His Majesty's Customs, and the incident still rankled in his manly bosom.

Without further interruption the boat ran alongside the deck of the "Aphrodite." Her crew jumped aboard the parent vessel, hauled the collapsible on deck and folded it.

"Look sharp, sir!" exclaimed Gwennap. "There's a steam-boat bearing right down upon us."

There was no time to be lost. Hastily the folded boat was dropped through the hatchway, her crew quickly followed and the hatch was reclosed. One touch and the emergency chambers were flooded, and the submarine began to sink to the bed of the river. It was a close thing for the picquet boat. Had she been a quarter of a minute earlier they would have stove her bows in against the massive plating of the elusive vessel. As it was she passed over the after-conning-tower with less than half a fathom of water to spare, utterly ignorant of the narrow escape she had had.

"Welcome home once more, Kenwyn!" said Mr. Devoran cordially, extending his hand, which the new arrival gripped like a vice and shook like a pump-handle.

Had the chief officer of Southsea Coast Guard Station, or P.C. 445 of the A Division of the Borough of Portsmouth Police been present at this reunion, they would have had no difficulty in recognizing Mr. Kenwyn as the quiet and very retiring unknown who had landed under most unusual circumstances on Southsea Beach.

"I had to abandon my diving-suit, sir," explained Kenwyn, who served on board the submarine in the capacity of second officer.

"That I have already learnt from Press reports," replied Captain Restronguet. "And I was glad to know that you took particular pains to get rid of the air reservoir. That did the authorities nicely; they are welcome to the dress, and if they can analyse the metal it is composed of they are also at liberty to make use of the secret. It has not been patented. But how came you to get out of your bearings, Kenwyn? I notice you had to concoct a cock and bull yarn about walking from the beach at Gosport."

"I never tell a lie, sir, under any conditions. As a matter of fact, after I left the 'Aphrodite' I did go ashore at Gosport, somewhere behind a yacht yard. No one saw me. I then tried to cross to the Portsmouth side of the harbour to try and recover the submarine welding tool that Carnon, you may remember, dropped when we examined the entrance to No. 5 Shipbuilding Slip. Before I realized it the ebb tide caught me, and I was whisked off down the harbour at a rate of at least seven knots. As soon as I felt the current slacken I took compass bearings and came ashore, and the rest you know."

"You have, of course, heard that we have a naval officer on board?"

"Heard? Rather. The papers are full of it, sir, and every one is talking about it. At Exeter Station and again at Millbay, on my journey down, it was the sole topic of conversation on the platform."

"And how does the Great British Public like it?"

"In a general sense they are thankful it is no worse, so to speak. It is recognized that you are a power that cannot lightly be ignored, and your magnanimity (that is the way they put it) has created quite a favourable impression. Even in the House it was suggested that it would be a master-stroke in world supremacy if you could be induced to hand over the 'Aphrodite'----"

"Never!" declared Captain Restronguet vehemently, and bringing his fist down heavily upon the table. "Never! They had their chance, but foolishly threw it away. Now, gentlemen, it is nearly one o'clock. I, for one, will be glad to have a few hours' rest," and with an inclination of his head Captain Restronguet retired to his sleeping quarters.

CHAPTER XI.

CONCERNING CAPTAIN RESTRONGUET'S RIVAL.

It was broad daylight when Arnold Hythe awoke. He was surprised to find the "Aphrodite" lifting to the heave of the open sea, and the sunlight pouring in through a small circular scuttle above his bunk. Hastily springing out of bed he looked out. As far as his limited vision extended he could see nothing but blue water--a sure sign that the submarine was far from land. Judging by the apparent motion of the waves the "Aphrodite" was running at a bare ten knots--possibly less. And a few hours previously she had been lying motionless on the bed of the River Tamar.

Slung to the beams overhead was a metal bath, of a similar pattern to those supplied for officers' use in the Royal Navy, while in the bulkhead were two taps marked "hot" and "cold." On a chair by his bunk were his clothes, brushed and folded, while quite a large stock of new under-garments were lying on a folding table.

Hythe always prided himself upon being a sound sleeper, yet able to arouse at the slightest sound, but for once at least his faith in his capabilities received a rude shock. Some one had certainly entered whilst he slept, and also the "Aphrodite" had made a lengthy trip without his being aware of it.

The astonished young officer quickly tubbed and dressed. Then it occurred to him that he had not shaved. Lying on the dressing-table was a safety razor, also brand-new. Evidently his host had left nothing undone to contribute to the comfort of his guest.

His toilet completed Hythe stepped out into the alley-way. At the fore-end, and hitherto unnoticed by him, was a hatchway. It was now open and a ladder had been shipped under it.

An appetizing odour came from the captain's cabin. It made the sub feel hungry; but curiosity conquered, and he made his way on deck, or on Platform Number One as Captain Restronguet preferred to call it.

Hythe found himself on a flat deck nearly two hundred feet in length, and unbroken save for the low coamings of three hatchways and the fore and aft conning-towers. Metal stanchions and rails had been placed in position round the sides to prevent anyone from slipping overboard. As the sub looked down on the deck he noticed that, like the sides, it reflected his own image and those of other persons and objects on deck, but there was no dazzling glare from the sun that was now high in the heavens.

Clustered for'ard between the bows and the foremost conning-tower were nearly every member of the crew: twenty-five stalwart men all dressed in plain but serviceable rig. Pacing up and down between the two conning-towers were Mr. Devoran and some one whom Hythe had not previously seen--the Second Officer Kenwyn.

As they turned at the end of their promenade the two men caught sight of the sub.

"Good morning, Mr. Hythe," said the chief mate genially. "Quite a fine day after our sample of the English climate, eh? By the by, I don't think you know Kenwyn, our second officer? He only rejoined last night."

The three engaged in conversation of general interest for a few minutes, then Mr. Devoran asked Hythe if he had seen the captain that morning.

"Not yet," replied the sub. "I came straight on deck. It was a surprise to find myself at sea. Where are we?"

"Nearly twenty miles S.W. of Ushant," replied the chief mate. "We shall be cruising about here for a few days, as we expect to fall in with a certain vessel. We have left English waters for a time, at all events, but you need not worry about that, for the captain informed me that he received a reply to his note at four this morning. You are officially 'lent' to the 'Aphrodite' until further orders. But breakfast is ready, and Captain Restronguet will explain matters more fully."

The captain greeted Hythe with great affability, and both thoroughly hungry did justice to a good breakfast. Very little was said, and when the meal was over Captain Restronguet left the sub to his own devices while he made the customary rounds of the vessel under his command.

Accordingly Hythe went on deck once more. The "Aphrodite" was slowly forging ahead at a bare five knots, her course being N.N.W ¼ W. That meant although not actually retracing her course she was heading at an acute angle to it. It was a sort of "wash-and-mend clothes day," a function resembling the time-honoured custom of keeping Thursday afternoon on board the ships of His Majesty's Navy.

The French coast was still invisible, but less than five miles off the sky line was broken by curiously cut tanned sails of the Concarneau fishing fleet. Away to the north-west a huge liner, looking without masts and funnels more like an exaggerated Noah's Ark than anything else, was pelting through the water at a modest thirty-three knots. Perhaps had her officer of the watch chanced to direct his telescope in the direction of the "Aphrodite" he would at once conclude that he had sighted the sea serpent, for, owing to the invisible hue of her hull only the seated figures of the men on deck would come within the field of vision.

The submarine was floating fairly high out of the water. More than half of her ballast tanks had been "started," and consequently there was sufficient freeboard to allow the side scuttles to be opened. With considerable buoyancy she rolled a good deal, but with a true-born sailor's delight Hythe revelled in the motion.

At noon Captain Restronguet appeared on deck. Kenwyn had just "shot the sun" and was working out the vessel's position.

"It's about time she was here, Devoran," remarked the captain. "That is, if the report is authentic. Has the submarine detector given no warning?"

"No, sir, I've stationed Polglaze by it, and he won't be caught napping. She couldn't have passed before we arrived, sir?"

"I made due allowances, giving her ten knots above her estimated speed. But we must exercise patience. Ah! Mr. Hythe, no doubt you are wondering why we are dodging about here instead of playing harmless little tricks upon His Britannic Majesty's ships and naval establishments? Well, I think I ought to give you some explanation, so if you will kindly step below we can talk without interruption."

"By the by," continued Captain Restronguet, as the two men made their way to the cabin, "you asked me how the 'Aphrodite' is manoeuvred to bring her to the surface and vice versa. We have three distinct methods. The first is by means of horizontal rudders, there being a pair at both bow and stern; the second is by means of expelling water ballast, which is all very well so long as the ejecting pumps work properly. Hitherto we have had no trouble in this direction, but it is well to be prepared. Consequently we employ a third method--one for use in emergencies only. I make no secret of the fact that I borrowed the idea from the French. I prefer to be original, but at the same time in the interests of my crew I do not hesitate to adopt well-established devices. To each of the three sections of this vessel is fixed a detachable iron keel. The bolts are secured on the keelson by a single yet effective looking device. One thrust of a lever and a section of this keel is dropped. Should a compartment be half full of water there is sufficient buoyancy gained by the release of this dead-weight to lift the vessel to the surface."

"Isn't there a chance of the 'Aphrodite' buckling her plates in a heavy sea with that dead-weight split into three separate sections?" asked Hythe.

"As far as the 'Aphrodite' is concerned there are no heavy seas," replied his host. "At the first suspicion of bad weather we dive to eight fathoms, or more if necessary. Since, even in mid-Atlantic the waves rarely exceed forty feet in height, and the depth maintained by the submarine is regulated by the vertical height of water over her, there is nothing to be feared as far as the 'hogging' and 'sagging' stresses are concerned."

At Captain Restronguet's invitation the sub threw himself into an easy chair. He was eager to hear everything about this mysterious man and his marvellous vessel, and the fact that the Admiralty had given a formal consent for him to remain on board as an official observer relieved him of all anxiety.

"You may have noticed," said Captain Restronguet, "that I hinted that I had had a quarrel with the Admiralty. First let me tell you my real name is not Restronguet. What it is is outside the question."

"The name is French, I believe?"

"No, Cornish. Had you been well acquainted with the district around Falmouth you would have recognized the names of Restronguet, Kenwyn, Devoran and the rest of my crew as those of places in what I consider the foremost county in England. Of course that is a matter of opinion, but that opinion is shared by every Cornishman.

"Some years back my father owned several copper mines, or wheals as we call them, in the neighbourhood of Redruth, and as, in time, I would have control of them, had articled me to an electrical engineer in order that I might get an insight into that branch before I took over the mining supervision. Hardly was my apprenticeship complete when the wheals failed and my father was a ruined man. He died shortly afterwards and I was thrown utterly on my own resources, and although I was very sore about it at the time I have since realized that misfortune is often the purifying fire of a man's strength of mind.

"Just about that time the South African War broke out. I volunteered for the front, and was accepted. There I saw enough of war--although supposed to be conducted under the most humane principles--to make me hate it. You may look astonished, Mr. Hythe, but I mean what I say. War might be a necessary evil, but all the same it must be avoided if possible. You do not know how thankful I am that the present crisis between Great Britain and Germany is over. It may sound paradoxical, but with this powerful instrument of destruction under my control I hope to be a deterrent to any Power that attempts to dispute the supremacy of the sea with the country that is mine by birth.

"But to proceed. On my return to England I was down on my luck, and as a final resource I joined the electrical department of Devonport Dockyard as a fitter. It was not long before I saw that there was little chance of bettering myself. I had ability and energy, but no influence. Profiting by the experience gained in my apprenticeship I devised an improved method of electrical welding. It saved hundreds, possibly thousands of pounds, and I was rewarded with a paltry bonus of forty shillings.

"Needless to say I was very sick about it. Then an opportunity came. The copper boom revived the Cornish mining industry. The 'wheals' that my father had left me became prosperous, and I was able to throw up my employment with an unsympathetic State Employer. Arguing that a wave of failure might once more return over the mining industry I sold those under my control to a Company; took all my best workmen and one or two of my special friends--Devoran and Kenwyn amongst them--and bought a concession in the Island of Sumatra.

"Sumatra is a Dutch colony, as you doubtless know. The Dutch officials lack the energy of their fellow-countrymen at home and the consequence is that the whole of the Dutch East Indies stagnates. For years past the Germans have had an eye on those islands, but my belief is that Japan will be the future master of them. Possibly that accounts for numbers of Germans who settle in Sumatra and Java.

"Personally I rather like the German, when free from the excessive officialdom that pervades in the German Empire. They are good colonists, hard-working and law-abiding, in every foreign possession save their own, for in the latter the blighting effect of the be-uniformed official is fatal to individual success. We got on very well with our neighbours on the adjoining concessions, with one exception. That exception was a German named Karl von Harburg."

Captain Restronguet paused as if he feared that the growing excitability would overmaster him. He was evidently labouring under a strong recollection of bygone insults. Hythe had the sense to keep silence, he realized that the listener is the one who hears most.

"But before I say anything more about Karl von Harburg," continued the Captain, "I must mention another incident. The concession I had acquired paid beyond all expectations, for not only were copper and tin found in abundance but also gold. We were all rich men. Some of my workmen went back to Redruth; others, having no home ties, and liking the free open life, stayed on. Since I was naturally fond of electrical engineering and the allied sciences, I spent a great deal of my time experimenting. One day, almost by accident, I discovered an alloy--as light as aluminium, absolutely showing no traces of corrosion when exposed to the action of salt water, as proof against acids as pure gold, and possessing the strength and resilience of steel. It was also as non-porous as a metal can possibly be. Under pressure that would cause water to 'weep' through a steel vessel, a cylinder made of this metal showed no sign of moisture. I realized that I had made a discovery that would prove of inestimable value in the construction of air-ships, and as at that time the Admiralty were 'tied up in knots' over the utter failure of the naval airship 'Mayfly,' I sent a sheet of the metal to a trusted agent in London with instructions to submit it to My Lords.

"Believe me from that day to this, beyond a curt acknowledgment and a bald statement that the subject was under consideration, I have heard nothing further of the matter. I was angry--disgusted because the powers that be had bluntly shut their eyes to an actual discovery that would give Great Britain the command of the air.

"Since airmanship did not appeal to me I resolved to make use of my discovery in another direction. By further experiments I found that my metal 'Restronium,' I have been ambitious enough to call it, could be made capable of absorbing bright light, yet at close distance would act as a reflector. The result was that I devised a submarine, steel-clad, and cased with restronium. It was constructed by native workmen under the supervision of my comrades and myself.

"The craft was a success. It prompted me to attempt another on a more ambitious scale, but ere it was completed Karl von Harburg appeared on the scene.

"This fellow is as crafty as a rogue can possibly be. By his German co-colonists he was cordially hated. He had ability but was lazy. His factory did not do so well as the others; instead of working harder he sulked. In the Fatherland he had once held a high diplomatic position. He it was who a few years back tried to force a quarrel upon Holland in order that a pretext might be found for Germany to acquire a longer coast-line on the shores of the North Sea. He failed, and since failure is not tolerated in Teutonic diplomatic circles, he was disgraced. He came to Sumatra, ostensibly with the idea of working a concession, but in reality looking for an opportunity of recovering his lost prestige by smoothing the way for a German annexation of the Dutch East Indies. Again he failed--how and why I need not now mention; but rightly or wrongly he formed the idea that I had a say in the matter.

"He had his revenge. He stole the secret of my new alloy. He obtained possession of the plans of my latest submarine, the 'Aphrodite,' and set himself to build a vessel that would be more powerful than mine. But he had not mastered one important idea--the secret of the defensive and offensive powers of my vessel.

"It was a case of war to the knife. His idea was to take his submarine--the 'Vorwartz' he named her--into British waters and deliberately do as much destruction to British ships of war and merchantmen as he possibly could; this with the idea of giving the Fatherland an advantage in the coming naval war that has been so long anticipated and which has not yet, thank God, caused untold misery and disaster to two nations who could be rivals yet friends.

"That is where I stepped in. I sent word and told the fellow plainly that the 'Aphrodite' was also bound for British waters, and that I would take the first opportunity of smashing up the 'Vorwartz' should one hostile act be committed against British property. That frightened him, for at heart he is a coward. Accordingly Karl von Harburg, knowing that the 'Aphrodite' had left for the Atlantic, concocted a truly diabolical plot. He deliberately navigated his 'Vorwartz' to German waters and committed outrages against his own country."

"Whatever for?" asked the Sub. "It is inconceivable."

"To a Briton, yes!" assented Captain Restronguet. "But Karl von Harburg had no compunction. He had a spite against his Government, he had a grudge against me; and whatever the issue he had nothing to lose by being the means of a terrible conflict between Great Britain and Germany. Thus he impersonated me, and by committing these outrages upon the German fleet and harbours he very nearly provoked the war he wished to engineer.

"It was time for me to dissociate myself with the authorship of these acts of piracy. Although I have registered a solemn oath never to hand my 'Aphrodite' over to the British Government (yet there are times when I feel tempted to perjure myself) I am still an Englishman. Should the Empire require my aid I for my part will do my best. And thus, having succeeded in demonstrating that I could not possibly be responsible for the work of destruction at Wilhelmshaven, Kiel, and elsewhere, I mean to lay in wait for the 'Vorwartz' and destroy her as ruthlessly as I would a venomous reptile. For this purpose, Mr. Hythe, is the 'Aphrodite' now cruising off Cape Ushant, for according to fairly reliable information the 'Vorwartz,' with Karl von Harburg on board, has passed through the straits of Dover bound west."

CHAPTER XII.

THE "VORWARTZ" IS SIGHTED.

"Then there is a great possibility of a scrap, sir?" asked Hythe, his face flushing and his eyes glistening at the prospect.

"Undoubtedly von Harburg will do his best to annihilate the 'Aphrodite,'" replied Captain Restronguet. "Perhaps, after all, I ought to have landed you. It is hardly fair to expose you to danger on my account. But it is not too late. We can put you aboard one of those fishing-luggers."

"I am not afraid, sir," exclaimed Hythe, rather indignantly, for the suggestion was not one that he could bear without more than a formal protest.

"I never for one moment had that idea," remarked Captain Restronguet. "The point I raised is that it would hardly do for me to place you in a dangerous situation while you are my guest on board. It is also unfair to your employers--the Admiralty. Good, bad or indifferent though a naval officer may be he has cost the country a large sum for his professional education, and it seems inconsistent that you should be given a chance of being knocked out in a petty feud."

"From what you have just told me the business is more than a private feud," objected the sub. "In order to carry out my part and learn all I can about the vessel it is only reasonable that I should see her under every possible condition. Therein I am doing my duty to My Lords. If I am to be killed in action, well, there's an end of it."

"A bit of a fatalist, eh?"

"In a limited sense. I believe in taking care of myself. For instance----"

A telephone bell ringing loudly interrupted Hythe's remark. Captain Restronguet took up the receiver and held it to his ear; then without replying replaced the instrument.

"I thought we should not be mistaken," he announced. "The 'Vorwartz' is bowling along in our direction. Our detectors make it appear that she's less than ten miles off and running beneath the surface. There is no time to be lost if we want to clear for action."

So saying Captain Restronguet hastened to the fore conning-tower. Whether he meant to take the sub with him or otherwise Hythe did not know; so pending directions he remained in the cabin.

Every officer and man of the "Aphrodite's" crew knew exactly what had to be done. As if by magic the stanchions and rails were cleared away, the "week's washing" bundled down the fore-hatch and placed in a compartment artificially heated. In two minutes the Upper Platform was deserted, and the water-tight hatches placed in position and properly secured. One touch of an electric push and all the circular scuttles in the vessel's side were simultaneously closed and covered with metal plates.

A bell tinkled in the after conning-tower, where Mr. Devoran was in charge. It was the signal that all was in readiness for diving.

"How is she lying?" asked Captain Restronguet of his chief officer by means of the telephone.

"Less than two miles due north, sir," replied Devoran, after giving a hasty glance at the electric detector that by means of two indicators automatically recorded the course of the "Vorwartz."

Captain Restronguet waited no longer. The time had arrived for the "Aphrodite" to dive and intercept Karl von Harburg's submarine, and only by the fact that the gentle rolling of the vessel had ceased did Hythe realize that she no longer floated on the surface.

Left to himself the sub was beginning to get "jumpy." It was a feeling akin to the sensation he experienced on the occasions when he saw the submarine at Spithead and in Cawsand Bay--not fear but nervous excitability. Had he been in the conning-tower he would no doubt have been as cool as a cucumber, being able to see what the others were doing and what was going on outside, as far as the limited range of vision would permit. But to be cooped up in a cabin, utterly alone, and with the possibility of the "Aphrodite" coming off second-best in the encounter that was to ensue did not at all suit the young naval officer.

Suddenly he staggered and only saved himself by grasping a corner of the table. The "Aphrodite," running at great speed, had ported her helm. So sensitive was she to the action of the rudder that she turned round almost on her heel, and the effect upon Hythe was similar to that of a man standing in a railway carriage when the train takes a sharp curve.

The sub braced himself together. He realized that in his opinion he ought to be taking part in the fun instead of remaining cooped up in a cabin, incapable of raising a finger to save himself should anything occur. He had no doubt as to the justifiability of his resolve; had there been only a private feud between Captain Restronguet and Karl von Harburg he would have hesitated, but the German had been guilty of international outrages. He had actually committed damage to the property of a foreign Government, and by so doing had very nearly succeeded in drawing Great Britain into a dreadful war. On that account Karl von Harburg was a pirate, a national enemy, and as such might be captured or destroyed.

Having quickly made up his mind Hythe left the cabin and hurried along the alley-way; but before he had traversed half its length a dull thud seemed to strike the port side of the submarine. The "Aphrodite" staggered under the blow and heeled over to starboard. For some moments the vessel showed no signs of recovering, then slowly she righted and swung over to port, ere she settled in her normal position.

At first Hythe thought the "Aphrodite" had been hulled in the for'ard compartment. He expected to see the submarine settling by the bows, and it was to his surprise and relief to find that such a catastrophe had not occurred.

When he came to the after bulkhead watertight door he found it secured. To attempt to open it would probably jeopardize the safety of the vessel, and Hythe was too good a sailor to tamper with the securing bars.

"Might have known that," he growled. "Now, what's to be done."

Another thud, this time to starboard, made the "Aphrodite" tremble again, but there was no disconcerting heel following the shock. Hythe had no doubt about it; the concussions were caused by explosions, either of torpedoes or floating mines, outside the vessel.

"I wonder how many of these she'll stand?" he muttered, clambering up three or four rungs of a ladder and trying a manhole above his head. "Well, here goes. I'll try this hatchway. The cover isn't locked."

Back slid the metal slab, and the sub saw that he had opened a means of communication with the after conning-tower. The place was in semi-darkness, only the subdued light from the pale green water filtering in through the observation scuttles. As the electric-light from the alley-way flashed upwards one of the occupants of the conning-tower glanced down and gave an exclamation of annoyance, adding:--

"Hurry up and cover that hatchway. How can you expect me to see ahead with that glare under my eyes?"

"Sorry, Devoran," replied the sub, hastily skipping up the remaining portion of the ladder and replacing the cover.

"Oh, it's you, is it?" said the chief officer. "Sorry, I thought it was Polglaze. Can't talk now. Stand here, if you will."

Devoran indicated a place on his left, so that Hythe could see out of the for'ard and port scuttles. It was some time before his eyes grew accustomed to the half-light; then by degrees he saw that the "Aphrodite" was tearing through the water at a great speed. A hundred feet in front of him he could discern the fore-conning-tower, and beyond that nothing but water that faded into extensive gloom. No sign of the "Vorwartz" was to be seen.

Hythe stood and waited. Without doubt the "Aphrodite" was in chase of the rival submarine, so that the latter had attempted strong measures to beat off her pursuer, but the absence of anything to be seen came somewhat like a disappointment to the young naval officer.

Suddenly there was a wild disturbance in the water less than twenty yards abeam. Again the sickening concussion even more noticeable within the conning-tower than down below.

"Torpedo!" ejaculated Devoran. He had no time for further explanation, and Hythe was at a loss to understand how the dangerous missile had exploded without actually coming into contact with the metal plating of the submarine.

"What's that, by smoke!" ejaculated the chief officer, as in place of the almost inaudible purr of the motors came a most discordant clanging, jawing, and groaning of machinery, while by observing the compass Hythe saw that the "Aphrodite" was describing a wide circle to starboard.

"You've buckled one of your propeller shaftings," said the sub. "I've had some before. I know what those noises mean."

"I hope not, by Jove!" replied Devoran, and almost at that moment the telephone bell operator from the motor room rang. "You're right," continued the chief officer. "It is the propeller shaft; we're knocked out for the time being."

Captain Restronguet remained in the fore conning-tower till the indicator of the detector showed that the "Vorwartz" had put a safe distance between her and her pursuer; then leaving the course in the hands of a quartermaster, he gave orders for the "Aphrodite" to be brought to the surface.

Hythe would have forborne to question the captain at such an anxious time, but to the former's surprise Captain Restronguet hailed him quite genially and in a manner that showed no trace of his annoyance at being temporarily baffled.

"Well, Mr. Hythe, wherever have you been?" he asked. "I thought you were following me when I left the cabin, and never missed you till ten minutes ago. You see, I had to keep all my attention on what was going on."

"You said nothing about my accompanying you, sir," replied the sub. "As a matter of fact I took the liberty of going up into the after conning-tower."

"That was better than remaining below," agreed Captain Restronguet. "Only there was not so much to be seen. From the for'ard tower we caught sight of the 'Vorwartz' on two occasions."

"I should have thought you had her in sight the whole time, sir," remarked Hythe. "Otherwise I cannot see how you kept in her track."

"By means of the detectors. I can fix the position of the 'Vorwartz' to a nicety, and no doubt that scoundrel of a von Harburg can do the same, thanks to my invention, of which he basely availed himself. I suppose you know he let loose four torpedoes?"

"Yes; but it puzzled me to know why they exploded so far from the ship."

"The 'Aphrodite' can, when desired, be protected by a belt, as it were, of electric fluid, so long as she remains under water. Any explosion brought within that zone would be spontaneously ignited. It was a weak current that knocked all the stuffing out of you, when you were nearly run down at Spithead."

"Then, this submarine is practically invulnerable?"

"When submerged, yes. A mine or a torpedo cannot harm her, and at a depth of fifty feet she is out of all danger of being run down. On the surface she might, if perceived, be a target for a quick-firing gun, or she might be cut in two by a large, swiftly-moving steamer. Von Harburg, did he but know it, has a unique opportunity now our propeller shafting is gone; he might wait till we rose to the surface and then ram us."

"But why didn't you torpedo his 'Vorwartz'?" asked Hythe. "Your torpedoes would easily overtake that vessel."

"It was in my power to do so," replied Captain Restronguet calmly. "But I refuse to do so in the interests of humanity. It is part of my creed that human life is sacred, and should not be sacrificed unless absolutely necessary."

"But you vowed you would destroy the 'Vorwartz'?"

"Most certainly. What I wanted to do, and what I will, I hope, eventually be able to do, is to play with that wretched counterfeit of my submarine, and drive von Harburg into a state of panic. Then as soon as I can pursue the 'Vorwartz' into comparatively shallow water I will sink her--but if humanly possible, I will save her crew. Come on deck, Mr. Hythe. You will then be able to see how we tackle repairs of this description."

The sub followed his host on deck, where about half of the crew were engaged in rigging up a pair of sheer-legs over the stern. At the same time the water ballast was being ejected from the ballast tanks in the sternmost section of the vessel, while the bow compartment tanks correspondingly filled.

Lower and lower sank the for'ard portion of the "Aphrodite," while the after end rose out of the water till the blades of the polished propellers were exposed to view. From the head of the sheer-legs a double block was fixed, the tackle being brought to bear upon the damaged shafting.

"We're in luck, sir," shouted Kenwyn, who had lowered himself over the stern. "The metal is not fractured; it's a length of tarred rope wound round and round the boss of the propeller."

"Take axes and cut the rope through," ordered Captain Restronguet, addressing Carclew and Gwennap. "We'll soon clear that."

Hythe was not so sanguine. He had known rope to baffle the efforts of half a dozen men working for two hours in a similar case, for the strain is so great that the entanglement is compressed into a solid mass almost as hard as steel.

"Might I suggest a hack-saw?" he said. "That will do better, since there is less danger of harming the metal than with an axe. If you have no objection, sir, I will bear a hand."

"Certainly," replied Captain Restronguet.

Glad of an opportunity of doing something the sub borrowed a working suit, and with a bowline under his arms was lowered over the stern, where the two men were already astride the propeller brackets.

Hitherto the sea had been fairly calm, but with provoking suddenness the wind piped up, and vicious little wavelets began to splash over the energetic toilers. Desperately they hacked at the stubborn rope, removing the coils piece-meal. Higher and higher rose the waves, till the work became hazardous.

"Pass me that long marline-spike, Gwennap," exclaimed Hythe. The man leant forward with the pointed piece of steel in his hand. As he did so a sea swept over him; he dropped the marline-spike and grabbed frantically at one blade of the propeller; missed it, and the next instant was struggling in the sea.

"HE GRABBED FRANTICALLY AT ONE BLADE OF THE PROPELLER."
"HE GRABBED FRANTICALLY AT ONE BLADE OF THE PROPELLER."

One glance sufficed to show the sub that the unfortunate man could not swim a stroke. However competent he was underneath the sea in his diver's dress it was a certainty that he was absolutely helpless when it came to keeping on the surface. He raised his hands above his head, and in consequence sank. By the time he came to the surface again, the submarine, now light and high in the water, had been blown ten yards astern. The officers and men on deck were all equipped in heavy working-suits and sea-boots, while the dinghy, the only above-water life-saving appliance on board, was down below. There was not even a rope handy that was long enough.

Captain Restronguet, Devoran, and several others were struggling to cast off their cumbersome clothing and boots, but they were too late, for Hythe, slipping out of the bowline, dived into the water. Although more than fully clad, since he had donned overalls over his uniform, he fortunately was not wearing sea boots.

Striking out vigorously he gained the spot where Gwennap had sunk just as the man appeared for the second time. Bearing in mind the instructions laid down in official directions for saving life Hythe used a fair amount of precious breath in bawling in a loud voice that the drowning man was safe. Gripping Gwennap by the collar he jerked him on to his back, the man struggling furiously the while. Hythe, realizing that once the frantic and powerful fellow gripped him, it would be "all up," had his work cut out to avoid the man's arms. One glance showed him that the "Aphrodite" was drifting fairly fast to leeward; his assurance that the drowning man was safe seemed a hollow mockery.

"Don't struggle, you idiot!" spluttered Hythe, as the crest of a wave broke over his head. "Don't you see you'll do for the pair of us?"

But Gwennap evidently did not see, for if anything he struggled the more.

The sub came to the conclusion that the situation was a desperate one. He was rapidly becoming weaker; his clothes, now thoroughly waterlogged, seemed like leaden weights. He had lost all sense of direction; he knew not where the "Aphrodite" lay. It seemed as if he were left with a frantic, drowning man in the lone sea. But not for one moment did Hythe intend to abandon the man he had so gallantly attempted to rescue. If only he could prevail on Gwennap to keep fairly still a chance yet remained; but the man showed no signs of ceasing to struggle.

"Let go!" shouted Hythe, as loudly as he could, as Gwennap's huge fist seized him by the shoulder, followed by an iron grip on his coat-sleeve. In his effort to shake himself clear the sub sank. As he did so Gwennap's grip became a close embrace. Down, down, down; it seemed as if Hythe had sunk a full twenty feet ere the downward motion ceased. His lungs seemed ready to burst with the pressure. Even if he would he could not now free himself from the relentless grasp.

Once more his head appeared above the surface. He drew in a deep, reviving draught of air, even though it was salt-laden; then with a sudden effort he wrenched his right arm clear, drew back his fist, and planted a tremendous blow upon Gwennap's temple, and his struggles ceasing he was now practically harmless.

"Pity I didn't think of that before," thought Hythe dimly. "I wonder if I've killed him, but there was no other way."

"Cheer up, Hythe!" exclaimed a hearty voice that the sub recognized as Devoran's. Turning his head the well-nigh exhausted rescuer saw close to him the chief officer and O'Shaunessey, who, having divested themselves of the greater portion of their clothing, had dived overboard to aid their comrades.

"That's right, you hang on to me," continued Devoran, "O' Shaunessey will look after that lubber. The captain will give him a dressing-down when we get aboard again."

Hythe was too done up to inquire why Gwennap should be reprimanded. He was only too glad to rest his hand upon Devoran's brawny shoulder.

"We'll be all right in a brace of shakes," said the chief officer encouragingly. "The water's quite warm, and we are fresh enough. They are turning the 'Aphrodite' and will bring her to windward of us."

Ten minutes later, the submarine, with her upper platform barely three feet out of water, glided slowly up to the group of immersed men. Ropes were thrown and caught by Devoran and O' Shaunessey, and by this means Gwennap and Hythe were hauled on board. Captain Restronguet was waiting to congratulate his guest upon his heroic action, but instead he sprang forward and grasped Hythe by the arms, just in time to prevent the sub from falling helplessly to the deck.

CHAPTER XIII.

THE MISSING SUBMARINE.

When Arnold Hythe recovered consciousness he found himself lying on his bunk in the cabin that had been appropriated to his use. The scuttle was closed, an electric light was burning, and by the slight and peculiar oscillation of the vessel he knew that the "Aphrodite" was running submerged.

He was not alone. Sitting at the head of his bunk was Kenwyn, the second officer. He was reading a book, but hearing the sub move he replaced the volume on a shelf and asked Hythe how he felt.

"Not quite up to the mark, thanks. But what am I doing here? Ah, I remember. Have you got Gwennap safe on board?"

"Yes, thanks chiefly to you. He's still unconscious. Devoran told me he saw you knock the nonsense out of him, By Jove! I shouldn't like a blow like that."

"I hope I didn't hit him too hard?" asked the sub anxiously.

"Too hard? Not much. He's as tough as nails, and he thoroughly deserved to have his figure-head damaged. He is the only member of the ship's company who cannot swim, and the captain has been trying to get the fellow to learn for a long time past. But you are a plucky fellow, Hythe."

"Where are we making for now?" asked Hythe, seeking to change an embarrassing subject. "Has the propeller-shafting been cleared yet?"

"We're making for the North coast of Spain: Machichaco Bay, to be exact--a place a short distance to the east'ard of Cape Villano. You see, the rising sea and Gwennap's accident interrupted the work in hand, so Captain Restronguet, rather than put into any of the harbours on the French Biscayan coast, has decided to make for Machichaco Bay, where there are excellent facilities for repairing the damage without fear of interruption. We are running with only the port propeller, that gives us barely twelve knots when submerged, and at that rate we expect to sight land about mid day on Thursday."

"Is Captain Restronguet going to beach the 'Aphrodite' at half tide?" asked Hythe.

"Rather not. No, our repairs will be carried out on the floor of the bay, where we shall be unseen by every one. But don't talk any more at present. Drink this and try to go to sleep."

"But I don't want to go to sleep," expostulated Hythe.

"Very well, then, don't, only drink this. It will buck you up."

The sub took the glass proffered by the wily Kenwyn, and drained it at a gulp. Within three minutes he was sleeping peacefully.

When Hythe awoke again after an eight hour's sleep all traces of his strenuous exertions had vanished. He tubbed, dressed in his own clothes, which had meanwhile been dried and pressed, and went down to breakfast in the captain's cabin.

Captain Restronguet greeted his guest warmly, until Hythe felt quite uncomfortable at the praises bestowed upon him for his act of gallantry. Once more he succeeded in changing the subject, this time by asking if any news had been received of the "Vorwartz."

"Nothing that will give us definite information as to where she is making for," replied Captain Restronguet. "But from my British agent I have had news that Karl von Harburg has been declared a pirate by the Great Powers and by several lesser maritime states as well, and that war vessels are authorized to capture or destroy the 'Vorwartz' without compunction. I fancy, however, that that part of the business will be left to us."

"You mean to track him down?"

"Through the five oceans, if needs must. But for the time being we are put out of the running. Have you ever been to the north coast of Spain, Mr. Hythe?"

"Yes, to Bilbao, Santander, and Coruña; but it was two years ago, when I was in the old 'Alacrity.'"

"Then you don't know Machichaco Bay?"

"Never heard of it until Mr. Kenwyn mentioned the name to me, sir."

"H'm. Do you remember the disaster to 'La Flamme'?"

"The French submarine that was supposed to have been run down on her way from Rochefort to Toulon?"

"Yes, the Dutch liner 'Huitzens' arrived at Rotterdam about that time with several of her bow plates buckled, and reported she had been in collision with an unknown object thirty miles off Cape Finisterre. The theory was advanced and generally accepted that the liner ran down the French submarine."

"And didn't she? Do you know anything about it?" asked Hythe interestedly.

"I think I can show you certain evidence before many more days are passed. Ha, Devoran, what is it?"

"Cape Machichaco in sight, sir."

"Very good. We'll go to the fore conning-tower, Mr. Hythe. You will then be able to see how we con the 'Aphrodite' into this somewhat intricate roadstead."

The submarine was now running at a little less than eight knots and at thirty-five feet below the surface. The electrically operated periscope with its flexible attachments was in operation, and by looking at the object-board the sub could discern what appeared to be a range of hills, above which a remarkably-shaped peak towered to a considerable height. Close to the edge of the cliffs could be seen a circular lighthouse and the keeper's house, both painted white. Some little distance from the cape two forbidding looking rocks reared their gaunt black heads above the sea, while between these rocks and the shore was a tumbling mass of white foam.

"Is that the cape? Where, then, is the bay?" asked Hythe.

"It is hardly recognizable from the distance. There it lies--away to the east'ard. A point to starboard, quartermaster--gently does it--so."

Slowly and steadily the "Aphrodite" approached the desired anchorage. Through the starboard observation scuttle the sub saw vicious-looking rocks more than once, rising boldly from the bottom of the sea at less than twenty yards off. Between them were cavernous depths that could only be compared to an American canyon suddenly submerged in a tremendous flood.

While the quartermaster kept the "Aphrodite" on her course Captain Restronguet directed all his attention to the submarine cliffs. Hythe could hear him counting as the dangerous rocks appeared to slip by.

"Hard a port."

Round swung the "Aphrodite" till her bows pointed straight for a narrow gap in the rocks. The sub stood aghast. Surely it was courting disaster to plunge into a submarine defile, so dark and so narrow that it seemed an impossibility for her to pass without touching the jagged pinnacles on either hand?

The gauge now showed a depth of fifty-five feet. At a sign from the captain, Kenwyn touched a switch and instantly two parallel beams of brilliant light flashed from the sides of the conning-tower. As far as the beams penetrated nothing but water could be seen, but in the reflected light on either hand the ghost-like rocks flitted past in a seemingly endless procession. The "Aphrodite" was threading an intricate passage between the dangerous shoals of Machichaco Bay.

Suddenly a weed-covered crag, looking like a pillar of glistening silver, came within the zone of the port search-light. A slight touch at the helm and the "Aphrodite" swung round, clearing the danger with comparative ease. On and on she went, literally crawling and smelling her way through that forbidding channel.

Presently Captain Restronguet touched Hythe upon the shoulder.

"Look!" said he, at the same time switching on a supplementary search-light that, instead of playing in a fore and aft direction, threw its beam at right angles to the submarine's course. For less than ten seconds the captain kept the light switched on, but in that short interval the sub saw something that made the blood run cold in his veins.

Perched upon a flat rock so insecurely that it seemed as if the faint "wash" from the "Aphrodite" would topple it over, was a regularly-shaped mass literally covered with barnacles and plentifully festooned with trailing seaweed. But even these disguises Hythe could penetrate: there was no mistaking the tapering stern, the horizontal and vertical rudders, and the twin screws of a standard type of submarine.

"'La Flamme,'" announced Captain Restronguet, at the same time raising his right hand to the salute in honour of the brave dead, an example that Hythe promptly followed.

A little farther and the twin search-lights played upon a solid barrier of rock, extending from side to side of the submerged gulley.

Placing the engine-room indicator to half-speed astern Captain Restronguet waited till the "Aphrodite's" way was checked; then turning to Mr. Devoran he nodded his head significantly.

Immediately the chief officer opened the valves of the subsidiary ballast tanks and the "Aphrodite" sank vertically to a depth of sixty-five feet beneath the surface, and rested firmly upon the sand on the bed of Machichaco Bay.

The sub glanced at his watch. Notwithstanding the fact that he had been wearing it when he dived overboard to the rescue of the man Gwennap it had sustained no damage whatsoever from its immersion. He was surprised to find that it was nine o'clock. Nearly an hour had elapsed since the submarine had first entered the tortuous defile.

"We cannot do more until daylight," announced Captain Restronguet, as soon as the patent anchors had obtained a firm hold in the sand. During the navigation of the "Aphrodite" through the dangerous channel he had been constrained; his whole attention had to be concentrated on his work, but now his usual willingness to impart information returned.

The search-lights, now no longer necessary, were switched off, so that no belated fishing-boat might have occasion to report the presence of a mysterious phosphorescence in the depths of the bay; and having received reassuring reports from various parts of the vessel the captain intimated that the somewhat long-delayed dinner would prove acceptable.

"I discovered this channel quite by accident," said the captain, during the progress of the meal. "We put in here on our way north, since the nautical directories state that here the currents run with great velocity. This step was necessary since our accumulators were rather run down and I particularly wished to have a good reserve of power for our run across the bay and up the English Channel. Of course, in a 'blind alley' such as we are in now, there are no eddies or currents to trouble us. I was looking for a good sheltered berth, for as far as we could see through the observation plate in the bottom of the vessel there was nothing but jagged rocks. We were moving very slowly, at twenty feet below the surface, when Mylor shouted that we were passing over a submarine. I at once thought that we were about to be attacked by the 'Vorwartz,' but Mylor promptly supplemented his first assertion by saying that the craft was a wreck."

"You say it is 'La Flamme,' sir"? asked Hythe. "How, then, is the fact to be accounted for that she was run down off Cape Finisterre?"

"She never was," replied Captain Restronguet calmly. "That was a statement based upon suggestions made by the liner's crew. No doubt they cut something down. The state of her bows proved that; but it was more likely that of a derelict or else perhaps an unfortunate fishing-vessel. Well, we found the channel, and by carefully feeling our way out, came to the current that served our purpose admirably."

"It is a tricky piece of navigation," remarked the sub.

"Not so much as one would think. You observed the two forward search-lights? Their beams are not exactly parallel, but slightly diverging. So long as the water illuminated by them is unobstructed I know that the 'Aphrodite' is safe. Directly any dangerous object comes within the field of light I know that it lies in the vessel's course, and have to alter helm accordingly."

"Did you examine the wrecked submarine?" asked Hythe.

"Yes; a brief external examination, but enough to satisfy me that it was 'La Flamme,' and also the manner in which she met her fate. To-morrow, while the repairs are being undertaken, I propose to make a fairly lengthy examination, both external and internal. Perhaps you would like to accompany me."

"I should, sir, with pleasure," replied Hythe.

"I warn you that the sight will not be a pleasant one. In fact, were it not for a definite purpose, I would hesitate to undertake the interior examination."

"I have seen a few gruesome things during the comparatively short time I have been in the Service, sir."

"Very well, then. I mean to write out a report and forward it to the French Government. Perhaps you will be so kind as to endorse it with your signature and rank? I have already mentioned that I regard myself as a humanitarian. I hope the report and the suggestions I make will go a long way towards abolishing submarine warfare."

"Abolish submarine warfare?" exclaimed Hythe, astonished at the suggestion, that to him--a naval officer, who had qualified in submarine work--was utterly absurd.

"Certainly," resumed his host. "With all due respect to the Geneva Convention its work is performed in a very slipshod manner. You are not allowed by international restrictions to poison wells, or use explosive bullets; yet you are permitted to employ enormous shells, mines, torpedoes, submarines, bombs from aircraft and a host of the most devilish ingenuities that civilized men can devise for the destruction of their fellow-beings. Which would you prefer, Mr. Hythe, to be quickly and painlessly poisoned when slaking your thirst on the field of battle, or to be horribly mutilated by fragments of a shell, and remain, perhaps for years, a misery to yourself and your fellows?"

The sub shook his head.

"By eliminating certain means of offence you reduce the limits of the horrors of war."

"Of the means only, the horrors of war will never be mitigated until the ban upon explosive shells, submarine, and aerial offence and defence is imposed. Thus I maintain that the Geneva Conference has only taken a middle course. Better by far to place no limitations and make war so horrible that no nation will dare draw the sword; or else restrict the weapons of offence to solid armour-piercing shells for naval warfare, small calibre rifle bullets and cold steel. To my mind submarine warfare, including torpedo work, is a despicable form of destruction."

"Yet you yourself are bent upon an errand of destruction by means of your submarine."

"Precisely. And it is the same in international warfare, because A builds a submarine, B must do likewise, in order to fight upon equal terms. But wait until to-morrow. When you have explored 'La Flamme' perhaps you may see eye to eye with me."

"What caused the disaster, sir?" asked Hythe.

"For the present I prefer not to answer that question," was the reply. "To-morrow I think I can explain more clearly."

After breakfast on the following morning a strong working-party, under the direction of the chief officer, prepared to tackle the task of freeing the propeller. Clad in their diving suits the men entered the air-lock and thence slipped out into the sea. Soon the hull resounded to the rasping of the hack-saws as the men attacked the hempen rope that was coiled tightly round the shafting.

"Are you ready, Mr. Hythe?" asked the captain.

The sub assented, and Captain Restronguet led the way for'ard to the divers' dressing-room. On the way he stopped, and asked his companion to accompany him to the after-conning-tower.

The sun was now shining brightly, and even at that depth the luminosity was sufficient to enable the interior of the conning-tower to be seen without the aid of artificial light.

"It is now nine o'clock," remarked Captain Restronguet. "On what quarter ought the sun to be visible at this hour?"

"South-east," replied Hythe promptly.

"Now look at its bearing according to our standard compass."

"Why, it bears south-west."

"Exactly. Now that explains the loss of 'La Flamme.' Practically the whole of this coast contains vast quantities of iron ore, and the deviation of the compass at this particular spot amounts to as much as ninety degrees. The north-west coast of Spain is bad enough in this respect. You may have heard of the loss of the 'Serpent,' several years ago. That was attributed to magnetic influence of the iron ore upon the ship's compass. Here the error is still greater. It is easy to understand that the unfortunate submarine, getting within the fatal influence of the magnetic attraction, ran full tilt upon the rocks in a heavy sea and on a pitch-dark night. But we will now prepare for our submarine walk."

In the dressing-room were Kenwyn, Carnon the quartermaster, and O'Shaunessey, who were also to form the party. The Irishman was somewhat doubtfully examining the dress and helmet served out to him. Anything that was not "regulation" he regarded with suspicion.

"Buck up, O'Shaunessey!" said the quartermaster. "Here's the cap'n; and you're not ready yet."

"Sure, I'm ready," replied the Irishman. "But can't I have me own dress?"

"You'll be sorry for yourself if you do," said Captain Restronguet who had overheard O'Shaunessey's remark. "Before you've gone fifty yards you will feel as if you're squashed between the jaws of a vice."

"You see," he added, turning to Hythe, "the air in a diving-dress fitted with an air-tube is kept under a fairly good pressure; with ours, the air supply being self-contained, only a very slight pressure is maintained. We rely upon the stiffening bands in the flexible metal fabric to withstand the exterior pressure of the water."

Having donned their diving garb, Polglaze served out to each man a small electric lamp. Captain Restronguet and Hythe both carried a steel crowbar, Kenyon a long adjustable spanner, while Carnon and O'Shaunessey took axes. The quartermaster was also equipped with a slate for writing messages, that being the only form of definite communication under water.

As soon as the five men entered the air-lock the water was admitted. When the compartment was full Captain Restronguet thrust back a couple of levers and a portion of the exterior plating of the hull was pushed aside. From the sill of this aperture to the bed of the sea was a drop of nearly ten feet. Unhesitatingly the captain leapt and sank upon a sandy floor, where he was joined by his companions.

Hythe found that walking in this form of dress was far easier than plodding along in the orthodox diving-suit in use in the British Navy. The absence of life-line and air-tube, with their attendant drag upon the diver, was particularly noticeable.

A short halt was made to examine the progress of the work upon the damaged propeller. Already the men had made a fair show with the job, but, as the sub had predicted, every strand had to be carefully cut through and prised up. Under the best conditions it would require another three hours of arduous labour to free the shafting from the obstruction.

At that depth the light was strong enough to see nearly twenty yards ahead, and Hythe was struck with the peculiar formation of the submarine gorge. It was as if human hands had hewn out a deep and narrow passage through the solid rock, here and there cutting side tunnels that faded away in the distant gloom. Fantastic marine growths occurred in patches that had to be carefully avoided, for some of the tendrils were armed with crooked spikes, sufficiently strong and sharp to do untold damage to any diver who was incautious enough to get into their toils. At other places fern-like weeds growing to a height of ten feet made the floor of the bay resemble a tropical-forest. Sponges grew in profusion; oyster-shells, a yard in diameter, were occasionally met with. Once O'Shaunessey's foot narrowly escaped being seized by the gaping jaws of one of these bivalves. A second later and his limb would have been crushed to a pulp.

As the five advanced crabs large and small swarmed sideways across their path to seek shelter amongst the rocks; fish in shoals darted from the unwonted sight of the diving-dresses, although a few, bolder or more stupid than the rest, swam quite close to the submarine pedestrians.

Presently the passage bifurcated, both arms shooting off at a very narrow angle. Unhesitatingly Captain Restronguet took the left. All the same Hythe wondered what would happen if they lost their way, for there was nothing whereby he could distinguish one way from another.

Stopping at one of the branch passages Captain Restronguet pointed towards it, then switching on his lamp began to clear away through the seaweed that grew to a height of nearly twenty feet. Hythe followed, tit was like pushing aside a Japanese curtain, for the flexible tendrils closed behind him.

The belt of weed was comparatively narrow; less than five yards brought the men to a close sandy space. Here the sub stopped. Right in front of him, and hidden from the natural light by a thick canopy of weeds, were the jagged, barnacle-encrusted timbers of a ship.

She was lying slightly over to starboard, but the list was enough to cause her double tier of guns to fall through the rotting planks. Her bowsprit had been carried away close to the gammoning; of her masts only two shattered stumps remained. Waterlogged cordage and sails trailed dolefully over her sloping deck, while her figurehead--that of a woman holding a rod--was just recognizable in its decay.

At each step, careful though they were, Hythe and his companions kicked up a cloud of iron rust, till the scene of desolation was almost blotted out. Of the ship's guns those that were of iron had almost crumbled into flakes of rust, but the brass cannon were in almost as good condition as they were when the wreck was a noble ship. The sub stooped and examined one of the brass pieces of ordnance. Close to the touch hole were the letters L.R. and the date 1692.

"A Frenchman: time of Louis XIV, by Jove!" said the sub to himself. "I wonder what her name is?"

He was on the point of walking towards the stern of the wreck when Captain Restronguet laid a detaining hand on his shoulder and flashed his light upon the rust-discoloured sand. Hythe instantly drew back. Almost under his feet yawned a hole full of trailing weeds that looked for all the world like a pit full of loathsome serpents.

Evidently understanding the reason for his companion's curiosity the captain beckoned to Carclew to approach. Then taking the quartermaster's slate he wrote in bold characters "La Sybille, French treasure-ship, sunk in action, 1695."

CHAPTER XIV.

"LA FLAMME."

Holding up his hand Captain Restronguet gave the signal for the party to retrace their footsteps to the main channel. It was about time, for the disturbed sediment from the crumbling wreck had obliterated every object beyond a distance of a yard.

The order of the procession was consequently reversed, Kenwyn leading and the captain bringing up the rear. Half way through the barrier of weed Hythe suddenly became aware that the man immediately in front of him had stopped and was stepping backwards. The next instant the sub was knocked sideways by a tremendous blow. Owing to the resistance of the water his fall was considerably broken, but he found himself lying in a veritable net of tendrils, while above him was some huge moving creature that was lashing out with almost irresistible force. Prudence counselled him to lie still, a sense of duty to his companions urged him to disentangle himself from the clutch of the weeds.

He chose the latter course, and contriving to free himself from the serpent-like tendrils he regained his feet, this time on the right side of the barrier of weeds.

It was a fearsome sight that met his gaze. Lying at full length upon the sand, and with his hands held in front of his helmet to protect the glass plate, was one of the divers whom the sub recognized as Kenwyn. Over him, and ready to spring upon another victim, was an enormous conger, more than eight feet in length and as thick round as a man's thigh.

Standing ready to lunge with his crowbar was Captain Restronguet, while with axes held ready in a position of attack were Carnon and O'Shaunessey.

Recovering his steel bar Hythe, though giddy with the effect of his fall, ranged alongside his friends.

The eel darted forwards. Captain Restronguet delivered a thrust and missed.

The next moment he, too, was capsized while the conger, darting over his body, retreated to the shelter of a hole in the rocks.

The captain was on his feet in an instant, while Kenwyn was assisted to rise. As no bubbles came from his dress it was evident that the attack had not seriously injured his diving-gear. Had the conger used its teeth instead of his tail the flexible metal fabric would have been bitten through as easily as if made of paper.

Kenwyn, however, walked unsteadily. The attack had not left him uninjured, but by a gesture he showed that he was quite able to continue the submarine excursion.

Once again the march was resumed, but ere they had gone another five paces O'Shaunessey happened to turn and look in the direction of the eel's retreat. He had just time to warn his comrades, for the conger, viewing the departing invaders as a sign of defeat, was preparing to renew the attack.

Like an arrow the snake-like monster darted forward! This time Captain Restronguet succeeded in thrusting his crowbar down the conger's throat, and by an almost superhuman effort pinned it to the sandy bed. Right and left the brute writhed its powerful tail. To withdraw the crowbar would be imprudent, to keep it there was obviously beyond the captain's strength in spite of his muscular powers.

Marking his opportunity Hythe planted his crowbar fairly through the eel's back. To any creature but a member of the fish tribe such a blow would have proved instantly fatal, but the conger only fought the more, till O'Shaunessey and Carnon cut its body into four pieces with their axes. Even then the severed portions continued to writhe. But the victory had been won, and once again Captain Restronguet led the way towards the lost submarine.

Half an hour's steady walking--the pace being about two miles an hour--brought the explorers to the ledge on which the ill-fated "La Flamme" lay. Bending his knees Captain Restronguet gave a rapid upward spring that took him nearly ten feet from the level of the channel, and sufficient for his outstretched hand to obtain a grip upon the edge of the rocky shelf. The sub, the quartermaster, O'Shaunessey, and lastly Kenwyn followed and gained the upper part of the rock, the only accident being that O'Shaunessey incautiously grasped the bracket of the sunken vessel's propeller shafting, with the result that his bare hands were badly lacerated by the knife-like edges of the barnacles.

To all outward appearance "La Flamme" was intact, but by removing the coating of molluscs and seaweed Captain Restronguet was able to point out a fracture about two feet from the bows.

Carclew and the Irishman next attacked the hatch abaft the conning-tower. Constructed to resist enormous pressure from without it was nevertheless comparatively easy to wrench up the steel covering that was held only in position by a gun-metal securing-bolt. The hatch was swung back and the cavity, within which the tragedy of two years' standing had hitherto been carefully guarded, lay open to inspection. But somehow even those strong-minded men--nerved to face hourly dangers beneath the surface of the fickle sea--hesitated. They stood around the open hatchway, looking at the repellent aperture, and at each other, till overcoming his repugnance the captain switched on his electric lamp, turned his face to the rusted steel ladder and descended.

Although now thoroughly loathing the task he had taken in hand Hythe felt compelled to follow. Not so the others: they remained on the slippery, weed-garbed deck.

The sub had steeled himself to see a gruesome sight, but his anticipations were excelled. In the pale light of the electric lamps he saw a scene so ghastly that his cast-iron nerve wellnigh broke down.

Every portion of the metal work of the interior bore traces of the corrosive action of the sulphuric acid, which escaping from the batteries had spread from end to end of the doomed craft. Luckily for the two adventurers the acid had long since exhausted its energies, otherwise their metallic dresses would have been eaten through by the powerful corrosive.

Almost the first compartment Hythe examined was the air-lock--that vaunted contrivance by which it was stoutly asserted that the crew of a disabled and waterlogged submarine could escape. Here were the skeletons of two men both overpowered in the act of attempting to draw the life-saving helmets over their heads. By the contortions of their bones it was fairly evident that they had struggled hard. Of the fifteen helmets only three had been removed from their places; twelve of the crew had been unable even to reach the place where safety had been promised, but where the promise had utterly failed.

Lying across the crank case of one of the motors was another body, blackened by sea water and petrol. Apparently this was one of the mechanicians who had by the impact been thrown across the powerful machinery, for his vertebra had been completely fractured. Grasped in the grisly hand was an oil-can. The poor fellow had literally died at his post. A clock on the motor-room bulkhead had stopped at a quarter to five.

Aft, the scene was even more horrible. Huddled together, some locked in each other's arms, others still in the act of vainly trying to raise themselves from their steel tomb, were nine corpses. Apparently as "La Flamme" sank she plunged bows foremost. These men had contrived to make their way aft, where the imprisoned air, compressed to several atmospheres, had been sufficient to prolong life for several minutes--literally periods of physical and mental torture.

Captain Restronguet flashed his lamp upon that awful group, then swiftly turning made his way down the steeply sloping deck, and gained the base of the ladder leading to the conning-tower. Here he waited for the sub to rejoin him, and again the pair hung back.

Hythe was visibly trembling. Within his diving dress the perspiration poured from him. This was the sort of danger that he had courted day after day with comparative equanimity.

Captain Restronguet flashed his lamp upwards. The rays revealed a pair of men's sea-boots jammed against an open steel grating. These boots were not empty--in them were the bones of a human leg. The rest of the poor creature lay huddled against the binnacle. By the tarnished uniform it was evident that the victim was either the lieutenant or the sous-lieutenant of the ill-fated craft.

As Hythe gained the upper platform a crab glided away from the heap of clothing--then another, and yet another. Overcoming his repugnance the sub grasped the end of a gold chain and pulled a watch from the unfortunate officer's pocket. It had stopped at seven o'clock. Allowing that both the motor-room clock and this timepiece were accurate until stopped by the water, one hour and three quarters had elapsed ere the air confined in the conning-tower had failed to support life. One hour and three quarters, imprisoned in a steel tomb without the faintest hope of rescue--this is but one of the risks men run in the race for sea supremacy!

In the upper story of the conning-tower they found yet another corpse--also an officer. He was untouched by water, for even after the lapse of time since the disaster there was still a considerable amount of air trapped in the steel citadel. He had found time to write, even in that awful impenetrable darkness, for across the open chart, written in lines that frequently overlapped each other, was the commencement of a fairly coherent report of the disaster.

After that the poor victim had been seized with a form of frenzy, for he had endeavoured to open the manhole in the conning-tower--failing that in his despair had tried to end his misery by shooting himself with his revolver, for the weapon, with all chambers empty, lay on the grating beside him. Even a swift and merciful death had been denied him, for in the darkness he had been unable to find the cartridges.

Hythe turned and descended the ladder as fast as he could. Captain Restronguet took the chart on which the course and the fragment of the report had been pencilled out and also the officer's rough log-book, and followed his companion. But the captain's investigations were not yet complete.

He made his way for'ard to where the two bow torpedo tubes were placed. This part of the submarine was deserted, save for a shoal of small fish of the sardine tribe. Their mode of entry was now apparent, for besides the rent in the plating, gaps the width of a man's finger were visible in the seams. The huge metal cylinder, which for dead-weight far exceeded a vessel of the same dimensions, had been hurled by the continued power of the twin propellers, and the irresistible force of the mountainous waves, at a tremendous pace upon the solid rocks--and the shock had not been sufficient to stun the unfortunate victims who formed the crew.

The two explorers having performed their duty, hastened to the open hatch. There with a common impulse they both stood stiffly erect and saluted. It was a tribute from men who had faced perils under the sea and who yet survived to those who, similarly situated, had sealed their devotion to duty with their lives.

"Well, Mr. Hythe, what did you think of that ghastly spectacle?" asked Captain Restronguet after their return to the "Aphrodite."

The sub was deadly pale. Hitherto he had looked only on the bright side of a submarine officer's life, now he had seen----

"It is simply horrible, sir."

"It is. And there are persons--experts they call themselves--who boldly maintain that death under these circumstances comes swiftly and painlessly. Would to heaven those men had been with us, and had seen what we have seen. Submarine work is a dangerous game."

"Yet you yourself----" began Hythe.

"Exactly. I know what you were about to observe. But my submarine is far in advance of the comparatively crude contrivances in which men seek to destroy their enemies. Possibly, in the interests of humanity, I ought to give my secret to the world. Has not that sight quenched all desire on your part to descend in an ordinary type of submarine again?"

Hythe rose from his chair.

"Sir," he replied stiffly, yet without any trace of grandiloquence, "it is my place to obey orders, and at times to withhold my opinion. But then I can safely say: so long as duty to King and Country calls, Britons will never be found wanting in the hour of peril, be it on, above, or under the sea."

CHAPTER XV.

A VISIT TO GIBRALTAR.

Breakfast on the following morning was a kind of solemn feast, for although Devoran and Kenwyn were present, hardly a word was spoken. The gloom of the previous day's exploration seemed to penetrate everything, yet the subject was, by mutual consent, studiously avoided.

The meal was nearly over when Lancarrow, the wireless man, knocked and entered the cabin.

"Message just received, sir," he announced unconcernedly.

Captain Restronguet opened the envelope and scanned its contents. Although his eyes lightened with satisfaction he said not a word till the man had retired.

"News of the 'Vorwartz,' gentlemen," he exclaimed. "She is reported to be operating off the entrance to Valetta Harbour, Malta. Holed the torpedo-boat-destroyer 'Tamar,' did considerable damage to the oil-tank vessel 'Petrolia,' so that the ship had to be beached in Bighi Bay. After that she slipped off. An aero-hydroplane followed her for an hour in an easterly direction. The 'Vorwartz' then dived much deeper and was lost sight off."

"What is she doing in the Mediterranean, sir?" asked Devoran. "That doesn't look as if she's returning to Sumatran waters."

"Unless she goes through the Suez Canal," added Kenwyn.

"She won't try that game," said Captain Restronguet. "There's not enough water in the canal. If she does we have been saved an unpleasant task, for the authorities will blow her to atoms."

"Now what is to be done, sir?" asked the chief officer.

Captain Restronguet paused a few moments before replying.

"The shafting is now all right, Mr. Devoran?"

"Yes, sir, I remained till the work was completed. That was at half past one in the morning."

"Excellent!" commented the captain. "There is now only one course left open to us. We must proceed to the eastern part of the Mediterranean and continue our search for this modern pirate. I'll send a message to the Admiralties at London, Paris, and Berlin informing them of my whereabouts and of my intentions. We may have a chance of sending the relics of 'La Flamme' ashore at Gibraltar, Mr. Hythe. Perhaps you would care to hand them over to the proper authorities?"

"With pleasure," replied the sub.

"There is no time to be lost," continued the captain, rising from his chair. "What is the weather like, Mr. Devoran?"

"Hazy, sir."

"Excellent! We may have a run on the surface; the extra ten knots may be of extreme importance."

"Must we go astern through this channel?" asked the sub, as he followed his host to the fore conning-tower. "There is not enough width to turn."

"Oh, no; we rise vertically to the surface," replied Captain Restronguet. "Coming here it was different. I could not depend upon sinking the 'Aphrodite' immediately over the gulley. Besides, I had reasons for bringing the craft in while submerged."

The discharging pumps were soon at work, and with hardly a jerk the heavy mass of water-tight metal casing rose majestically from the sandy bed of Machichaco Bay. When just awash her fore hatch was opened and the rails and stanchions shipped.

Hythe went on deck. The haze was sufficiently dense to prevent objects from being seen at a distance of more than a cable's length ahead. The cliffs and the lighthouse were invisible. Although there was hardly any wind and the "Aphrodite" was lying almost motionless on a perfectly calm sea, the noise of the sullen rollers breaking in-shore showed how dangerous this exposed bay was to any craft that attempted to send a boat ashore.

Beyond that ceaseless roar no sound disturbed the quietude. As far as the crew of the submarine were concerned they might have been floating peacefully in the midst of the wide Atlantic instead of almost within hailing distance of the Iberian shore.

The centre scuttle of the "Aphrodite's" for'ard conning-tower was opened so that the quartermaster could take verbal directions from his superior officer. Captain Restronguet stood just in front of the conning-tower, while two men, detailed for special duty as look-outs, were stationed in the bows, clad in oil-skins to protect them from the spray that was bound to come inboard as soon as the vessel gathered way. Abaft the after conning-tower Mr. Devoran had taken his stand, while right aft were more men whose duty it was to report the presence of any vessel that, of swifter speed than the submarine, might overtake her.

These precautions were additional to the use of the submarine detector that indicated the approach of any craft at a distance; for when travelling at high speed the swish of the waves against her lean bows was apt to be misconstrued by the men stationed at that electrically recording device.

Giving a glance at the standard compass to assure himself that he had made due allowance for the abnormal deviation Captain Restronguet gave the order for half speed ahead. Like a greyhound the "Aphrodite" leapt forward at a reduced speed of eighteen knots.

Within ten minutes the belt of haze had been left astern, and the sun shone brilliantly upon the clear blue water.

Hythe remained on deck some hours till the rounded point of Cape Ortegal hove in sight. Here the sea in calm weather is always agitated by a long heavy swell, while in gales the waves are dangerously steep. As a precautionary measure Captain Restronguet ordered the look-out men to make themselves fast with life-lines and the open hatches to be battened down. Although he suggested to the sub the advisability of going below, the captain, for some reason that he did not think fit to communicate, remained on deck. Scorning to make use of oilskins he stood grasping the handrail surrounding the conning-tower, and gazed fixedly at the horizon on the starboard bow. Whatever he expected to see his hopes in that direction were unfulfilled, and at five o'clock, after the tumultuous water had been left astern, he rejoined his guest in the cabin.

"We are so far fortunate in being able to keep on the surface," he remarked. "We are now off Cape Finisterre and right in the regular mail and ordinary trading routes. But up to the time I left the deck we had not sighted a single sail."

Twice during the day the "Aphrodite" had to dive to avoid being sighted by passing vessels, for although Captain Restronguet made no secret of his whereabouts he did not think fit to allow the submarine to be seen.

Just before midnight the captain called to Hythe as the latter was about to turn in.

"We are going to dive to eight fathoms," he announced. "It is advisable since we are approaching the Straits of Gibraltar. Perhaps you would care to have a look on deck before going to bed?"

On gaining the upper platform Hythe found that the "Aphrodite" was running nearly awash, with no navigation lights. Even the lamps in the conning-towers were screened. It was a pitch-dark night, although the atmosphere was clear. The water was exceptionally smooth for the Atlantic seaboard of the coast of Spain and Portugal.

Away on the starboard hand were several large vessels, each showing their green navigation lights, denoting that they were bound north. One, brilliantly illuminated, was evidently a liner on which the passengers were keeping a late night, for the distant strains of a string band were just audible above the subdued noise of her powerful engines.

"You know this coast, I suppose?" asked Captain Restronguet. "Do you recognize yonder light?"

The sub looked intently in the direction indicated. Through the darkness shone a fixed white light which increased and diminished in intensity, attaining its maximum glare every thirty seconds.

"Yes, Cape Trafalgar," he replied. "And we are within twelve miles of it."

"Otherwise it would appear to be a flashing light," added Captain Restronguet. "I see your knowledge of the various lights is exceptionally good. Had it been daylight we might have found time to let you have a sight of some of Nelson's relics, for we are passing over the scene of that ever-memorable victory. The bottom of the sea here is strewn with the remains of the French and Spanish vessels that were either sunk in action or foundered in the storm that arose after the fight was over."

"I have seen enough of naval disasters for the time being," remarked Hythe.

"You will soon get used to sights of that description," said the captain with a shrug of his shoulders. "Some day, all being well, I hope to visit the remains of the Russian vessels sunk at Tshushima. Not simply for idle curiosity, but with a definite motive. But it blows cold, so I think we may as well descend."

When Hythe awoke next morning the "Aphrodite" was at rest. Throwing back the metal slide over his cabin scuttle he looked out. The submarine was below the surface and in a fairly crowded anchorage, for dimly in the sunlit water he could distinguish more than one mooring chain and a mushroom anchor deeply embedded in the ooze.

"This must be Gib.," he thought, as he prepared to dress.

Although breakfast was laid, Captain Restronguet was busy writing as Hythe entered the cabin.

"Excuse me while I finish," said the former apologetically. "Here is a copy of this week's 'Gibraltar Herald'; it was published only yesterday, so it is fairly recent. Perhaps you might care to look at it?"

Hythe took the journal wonderingly. How could it have come into Captain Restronguet's possession? He sat down and opened the pages. Most of the news consisted of matter interesting only to the members of the colony, such as descriptions of social functions of such minor importance that the edition of the smallest weekly at home would scorn to make use of; but about one half of the back sheet was devoted to general news.

Three quarters of a column were occupied by a more or less accurate account of Karl von Harburg's doings at Malta. Since Captain Restronguet had exposed the fellow's identity the owner of the "Vorwartz" no longer attempted to screen himself by attributing his illegal acts to his rival; on the other hand the dénouement seemed to have emboldened him, for hitherto he had confined his active attentions solely to German national property. Now he was fast developing into a pirate, attacking all nations without any consideration. Yet, curiously enough, he never attempted to take booty, and on this account his motives were the subject of the keenest discussion.

Already international squadrons, representing Great Britain, France, Germany, Italy, Austria, Russia, and Greece were co-operating with a view of exterminating the modern buccaneer, while from Cape Tarifa to Centa a powerful flotilla of the latest type of submarines formed a cordon at the maximum depth attainable with safety beneath the surface. These in turn were supported by a number of destroyers and protected cruisers, while overhead aero-hydroplanes flew by day and naval airships soared by night, the latter keeping their searchlights playing vertically downwards in the hope of locating and annihilating the vampire of the seas.

The tension between England and Germany had, according to the paper, been considerably relaxed, and both the Atlantic Fleet and the High Seas Fleet had returned to their respective ports; but at the same time the British Prime Minister had spoken strongly in the House, urging the oft neglected precept that "A nation armed is a nation at peace."

The only other item of news that interested Hythe was a report that there had been seismic disturbances in the Mediterranean, and that Malta had experienced two severe shocks. The sub knew Malta well; besides, he had relations living there, his maternal uncle holding a shore appointment under the Admiralty. Although the effects of the tremor were felt at Bizerta, Tripoli, Syracuse, Messina, Reggio, and even as far north as Rome, Vesuvius and Etna showed no signs of increased activity, while Stromboli had ceased for several days to emit smoke. This phenomenon had been debated upon by men of science, but no satisfactory explanation had been arrived at.

"Have you found anything sufficiently interesting to make you forget my rudeness, Mr. Hythe?" asked Captain Restronguet, as he put his writing materials into his desk and locked it up. "I had to finish this dispatch, as you so kindly consented to take it ashore for me."

"I have been wondering how you obtained the paper, sir?"

"Easily done. We arrived in the bay about four this morning. Carclew immediately left the 'Aphrodite' and walked ashore, landing on the Neutral Ground about four hundred yards beyond the Advance Lines. He divested himself of his diving-dress and hid it, and as soon as the gun went--the signal for the gates of the fortress to be opened, as you know--he mingled with the crowd of locked-out Scorps, Spanish traders and pedlars, and walked unceremoniously into the town. Coming back, however, he had a nasty time, for the sentries had their suspicions, taking him for a smuggler, and it was as much as he could do to slip into the water without being seen."

"How do you propose to set me ashore?" asked Hythe.

"Perfectly openly," replied his host calmly. "I have the Governor's permission to send a representative ashore. You will land at the steps on the inner side of the New Mole at ten this morning. Kenwyn and Gwennap will accompany you as far as the landing in order to help you off with your gear. They will then return, so that no inquisitive individual will have an opportunity of examining or possibly stealing my patent helmet. At six p.m. sharp, Kenwyn and Gwennap will meet you at the same place. By the by, would you like O'Shaunessey to go with you?"

The sub hesitated for a moment before replying. Captain Restronguet had made no conditions regarding his trip ashore. He trusted entirely to the honour of the young officer. There was nothing to prevent Hythe and O'Shaunessey from remaining at Gib. if they felt inclined. The sub knew O'Shaunessey to be a sharp and diligent man, but unfortunately he had a great failing. Had it not been for a few delinquencies in the shape of overstaying his leave the Irishman might have been a petty officer by this time. Consequently, since the man might get into one of the numerous grog-shops and fail to return to time, Hythe decided not to take him.

"Very good, Mr. Hythe," replied Captain Restronguet in even tones, although the sub detected a glint of satisfaction in his eyes. "I quite understand, and I think your judgment is good in this respect. Now let us fall to; breakfast will be getting quite cold, and I do not want my emissary to start on a journey with discomfort."

"Where are we lying now?" asked Hythe, in the course of the meal.

"In the Commercial Anchorage, on a line with the Devil's Tower open of the North Front," replied the captain. "I thought it best to do so, rather than trespass within the limits of the Admiralty Anchorage. You will have more than a mile to walk, but the tides close inshore are weak, and by keeping close to the Old Mole you will find little inconvenience.

"Here are the documents," he continued, as soon as breakfast was over. "This one, to which is attached the chart from 'La Flamme,' is for the French Minister of Marine. It will be safely forwarded. This is for the Governor; the others are of a private nature, and will be sent in by post in the ordinary way."

"I heard say you are going ashore, sir," said O'Shaunessey, who was standing in the diving-gear compartment. "Wud ye take this letther for me? Sure, 'tis for me ould mother."

"I will, O'Shaunessey," replied Hythe. He almost wavered in his resolution not to take the A.B. with him; but since the Irishman did not seem at all anxious to enjoy a spell on land the sub adhered to his former plans.

Guided by a watertight compass held by the chief officer, Hythe, with his dispatches in a weighted metal case, set out on his lengthy submarine walk. Without a hitch the three men gained the base of the northernmost Mole, and walking under the keels of several merchant vessels made fast alongside, they arrived at the landing indicated by Captain Restronguet.

As soon as Hythe emerged from the water, greatly to the interest of a swarm of bluejackets and civilians who had been apprised of the arrival of the mysterious submarine, Kenwyn and Gwennap divested him of his diving suit, and, being unable to speak by reason of their helmets, raised their right hands in token of farewell.

Being ashore seemed quite unfamiliar to the young officer, although he was well acquainted with that landing place. Briskly he ran up the steps, made his way through the admiring and attentive crowd, and shaped a course for the Governor's Palace.

"So you are returning to the submarine?" asked the Governor, when the interview was at an end. "I believe the Admiralty have telegraphed that you can exercise your discretion in the matter."

"Yes," replied Hythe. "I think it necessary to do so, both from an official and a private sense. I can assure you, sir, that anything approaching the craft in mechanism and scientific wonder has never yet been seen."

"My Lords are naturally anxious for details," remarked the Rear Admiral in charge of the Naval Establishments at Gibraltar, who had made it a point of being with the Governor on the occasion of Hythe's visit. "In fact, speaking in a strictly confidential manner, I may as well tell you that they would like to open negotiations with Captain Restronguet for the purchase of the vessel. Could you approach him on this matter?"

"I am afraid it will be of no use, sir," replied the sub. "But, of course, I will do my best. Captain Restronguet is a man of iron resolution, and he has more than once told me that he has sworn to sink the 'Aphrodite' rather than hand her over to the Admiralty."

"That is a pity," said the Governor. "Why is this? He is an Englishman?"

"Yes, a native of Cornwall; but he is labouring under the impression that he has been slighted by the Admiralty. He offered his invention some years ago and was, he informs me, shabbily treated."

"Unfortunately that is not the only case," said the Admiral. "The mistake--for mistake it undoubtedly is--was possibly the work of some petty official at Whitehall. I've known plenty of instances of that description. However, Mr. Hythe, do your best in that direction, and find means to communicate Captain Restronguet's decision as soon as possible. He will not, I hope, sell the submarine to a foreign power?"

"No, sir; I think with all his prejudices Captain Restronguet does not forget he's an Englishman. Otherwise he would not be so open in explaining a host of details connected with his vessel to me."

"Well, we must hope for the best," declared the Governor.

"And if Captain Restronguet succeeds in destroying this rascally German's submarine--the 'Vorwartz,' is it not?--we shall have something to be thankful for."

Hythe made good use of the rest of the time allowed him ashore. Several of his brother officers, whom he had known on previous commissions, soon had him "in tow," but the sub strenuously declined to go aboard any of the ships. There might be some mistake, he might forget how the hours sped, and to miss his appointment at the New Mole was not to be thought of. He found an opportunity, however, of replenishing his scanty stock of clothing, and by means of a small "tip" enlisted the services of a "Scorp" to purchase a supplementary kit for O'Shaunessey. These he had placed in a small tin trunk, the lid of which was securely soldered down, and engaging a porter he told the man to follow him to the landing.

It was now close on the hour fixed for his return, but a sudden obstacle was thrown in his way; he had forgotten the Customs.

An alert Customs Officer, who was no respecter of persons even though they were in naval officer's uniform, peremptorily demanded to see what the trunk contained.

"Clothing only," replied Hythe, with considerable annoyance. "Value Five Pounds; here is my bill."

"Must see what's inside, sir," replied the man. "Please to order your porter to carry this box to the office. You will also step this way, sir."

"Look here, this is all rot!" exclaimed Hythe indignantly. "I'll pay up, even though it's a blind rush; but I've an appointment to keep."

The Customs official was obdurate. The sub glanced at his watch. It had stopped. He had forgotten to wind it. By a neighbouring clock it wanted five minutes to six.

Hythe hesitated no longer. Turning he set off at full speed towards the Governor's palace, the Customs man pelting at his heels and shouting to the bystanders to stop him. The sub was a good sprinter, even though considerably out of practice by being cooped up in the limited quarters of a submarine. Dashing past the astonished sentry at the entrance to the palace, before the soldier had time to salute, Hythe literally thrust his way into the Governor's presence and hastily told him of his irritating and serious encounter with the officious Customs man.

"He is undoubtedly within his rights, Mr. Hythe," replied the Governor. "But, at the same time, he is over zealous. That will clear you," and sitting down he wrote out and signed an order to pass Mr. Arnold Hythe's baggage.

One minute to six. With almost indecent haste the sub once more bade the Governor farewell and resumed his headlong pace.

Just outside the Dockyard Gate he overtook the Customs official, who was puffing and blowing after his exertions on a fruitless chase.

"Very good, sir," exclaimed the man apologetically, "but you see dooty's dooty. I'll clear your trunk in a jiffy."

Bubbling over with impatience Hythe set off at a rapid rate, with the wellnigh exhausted official at his heels. A fresh catastrophe confronted him, for upon arriving at the place where he had left the porter with his trunk neither was to be seen.

"He's a wrong 'un, sir," exclaimed the Customs man. "You had better inform the police."

"Haven't time," exclaimed Hythe savagely, and without another word he ran towards the steps at the New Mole. When he arrived it was ten minutes past six, and no signs of Kenwyn and Gwennap were to be seen.

"That's done it!" ejaculated the sub. "And Captain Restronguet said six o'clock sharp."

CHAPTER XVI.

OVER A VOLCANO.

If ever a man felt like kicking himself it was Arnold Hythe at that moment. He had missed his appointment; and in Captain Restronguet's eyes he would be regarded as a waster devoid of any sense of honour or gratitude.

"Have you seen anything of two divers?" he asked, addressing the crowd that lingered about the landing; for, though the time fixed for his departure had been kept a secret, a curious throng had loitered there nearly all day.

"Yes," shouted a dozen voices in chorus, and amid a babel of vociferations the sub contrived to gain the information that they had appeared quite half an hour ago, had waited ten minutes and had disappeared.

"Are you quite sure they went before six?" asked Hythe.

"Perfectly sure, sir, it was exactly ten minutes to six when they went down," replied a sailor confidently.

Then the thought flashed across his mind, perhaps Captain Restronguet had purposely marooned him? An instant later he banished the suggestion, yet why should Kenwyn and Gwennap have returned before the appointed time?

Hythe resolved to wait and see if anything fresh transpired. The crowd increased, several naval officers and dockyard officials mingling in the throng. Presently the Admiral came down and asked if he should order anything to be done to attract the "Aphrodite's" attention.

"They may come back even yet, sir," replied the sub. "I'll wait a little longer."

"If you hear nothing by seven you may as well have dinner at Admiralty House, Mr. Hythe," observed the Admiral.

Just at that moment two men in uniform arrived carrying Hythe's trunk. The thief had been caught and was under lock and key.

"That's something to be thankful for," soliloquized the sub. "To lose one's belongings and one's ship at one time is a bit too thick."

A sudden shout of exclamations from the crowd caused him to turn and look towards the slide of the Mole. Like a huge porpoise the twin conning-towers and flat deck of the "Aphrodite" appeared upon the surface, the water pouring in cascades from her smooth substance. As easily as a ship's pinnace she ran alongside the steps, her after-hatch was thrown open and Captain Restronguet appeared.

"Come on, Mr. Hythe!" he exclaimed.

The sub waited for no second bidding. With a bound he gained the Upper Platform, and turned and saluted the astonished Admiral. Having seen his belongings passed on board he followed his host below.

Fifty seconds later the dense crowd of spectators were gazing dumfounded at the unbroken wavelets. For the first time had human eyes, other than those of her crew, seen the redoubtable "Aphrodite" at close quarters above the surface of her natural element.

*      *      *      *      *

"Yes, I was certainly surprised when Kenwyn returned with the news that you were not at the rendezvous, Mr. Hythe," said Captain Restronguet. "Then the thought suddenly struck me."

"What thought, sir?"

"Might I ask what time you went by?"

"The local time; my watch had stopped. By Jove! I see what happened. Gib. time is 21 minutes 28 seconds slower than Greenwich."

"Just so. I guessed the mistake arose that way; so, as a considerable amount of precious time would be wasted in sending Kenwyn and Gwennap ashore again, I took the unusual course of bringing the 'Aphrodite' right alongside the New Mole. It will give the Scorpions something to talk about."

"And the naval authorities as well, sir. The Admiral was there."

"Now we are off as hard as we can pelt for the Eastern Mediterranean. I mean to keep at good depth till clear of the patrols of the Straits. The 'Vorwartz' is reported in the Black Sea, so I suppose the Russians will get excited. Anyway, I hope to be able to arrive in the Ægean Sea and intercept Herr Karl von Harburg as he returns through the Dardanelles."

Night had fallen ere the "Aphrodite" rounded Europa Point, and with the favouring east-going current was well beyond the cruising ground of the British submarines.

Two days later she was between Cape Bon on the Tunisian shore and the western extremity of Sicily. Captain Restronguet had, in view of recent developments, decided not to touch at Malta, but proceed as fast as he could to Grecian waters, where he hoped to be able to replenish his accumulators and be in a state of readiness for his hated rival.

Hythe had retired to his bunk. He had had a heavy day in the conning-tower, where, in reply to his host's invitation, he had stood a watch in order to acquaint himself with the delicate organization of electrical mechanism that controlled the submarine.

The "Aphrodite" had been running on the surface during the day, but to obviate the risk of being struck by passing vessels she was submerged to nine fathoms at sunset.

Suddenly the sub found himself struggling on the steeply listing floor of his cabin. The place was in utter darkness. All around him were weird noises caused by various articles breaking adrift, mingled with the shouts of the alarmed crew, while from without came an awe-inspiring rumble.

Struggling to his feet the sub groped for the electric light switch. The current was off. More and more became the list till his feet slipped from under him, and he fell into the angle formed by the floor and the fore and aft bulkhead of the cabin. Above the noise he could distinguish the captain's voice shouting for the emergency ballast tanks to be emptied.

"Good heavens! She's been struck. We're done for this time," exclaimed Hythe, with lively recollections of the ill-fated "La Flamme" fresh in his memory. He gained his feet and made for the door, but ere he could fling it open the "Aphrodite" spun round as if pivoted amidships. Full length went the sub once more, his hands grasping the knob of the door, which had come off in the strain. The racket of the shifting gear was redoubled. Every moment Hythe expected the enormous pressure of water, since he was fully certain that the vessel was plunging downwards, would burst in the sides of the submarine.

Another nerve-racking twist and the "Aphrodite" began to dip her bows till this time the sub found his sliding movement checked by the fore and aft bulkhead. Then, with a rattle and clank of her complicated machinery, the propellers began to race, while the vessel danced about like a gigantic cork. Instead of plunging down the submarine had been raised to the surface, and was being tossed about on the crests of an angry sea.

After considerable trouble Hythe succeeded in opening the door. Outside in the alley-way all was in darkness. He groped his way towards the fore conning-tower, staggering against the metal wall with each abnormal heave of the vessel. Before he had traversed many feet he came into violent contact with a man whom he recognized by his voice as the chief officer.

"What's up, Devoran?" he asked.

"Heaven only knows, Mr. Hythe. Until we get the light switched on it will be difficult to find out. One thing, we are afloat, and riding easily."

"Much too easily for my liking," remarked Hythe, although he felt considerably reassured that the "Aphrodite" had risen.

"Where are you going?" asked Devoran.

"To the for'ard conning-tower."

"No use," replied the chief officer laconically. "All principal watertight doors are closed. Captain's for'ard. Best to go to the after conning-tower if you want to see anything. I left Kenwyn there."

The sub made for the steel ladder communicating with Kenwyn's post, and as he did so he heard Devoran raise the flap of the hatchway to the motor-room and ask Carclew what in the name of Pontius Pilate's grandmother was the matter with the light?

"Plug fused, sir. I am replacing it," shouted Carclew.

"Then for goodness' sake hurry up!" replied the chief officer.

Hythe found Kenwyn staring out of the scuttle at nothing. It was so pitch dark that without the conning-tower everything seemed an impenetrable mass of darkness--sea and sky a chaos of invisibility. All the while the submarine was pitching and tossing like an empty barrel.

"That you, Mr. Hythe," exclaimed the second officer, unmistakably glad to have some one to speak to. "Isn't this a set-to? I don't know what can be happening."

Just then a brilliant flash of lightning played upon the turmoil of broken water without. In the pale-blue glare it seemed as if the surface of the angry sea was one expanse of tall, steep waves--an exaggerated tidal race.

"Ah, that's better," ejaculated Hythe, as the hiss of incoming water could be faintly distinguished above the hammering of the waves against the "Aphrodite's" sides and upon her deck. "We're diving once more."

At twelve fathoms the motion, though still erratic, became less marked, and the condition of things was vastly improved when the electric light was once more connected up.

Every available search-light was switched on, and as the powerful beams were directed through the scuttles Hythe and Kenwyn gave a simultaneous exclamation of surprise. Eddying through the water as far as the rays of light could penetrate were columns of smoke mingled with bubbles full of gaseous vapour. Now and again dark masses would shoot upwards with the velocity of a meteor.

"A submarine eruption, by Jove!" declared Hythe. "We're over the mouth of a submerged crater. That accounts for the earthquake shocks in Malta and elsewhere. Those black objects we see whizzing by must be lumps of lava."

Kenwyn placed his hand upon the side of the conning-tower. The metal felt quite warm to his touch. The thermometer registered eighty-five degrees.

"We'll be boiled alive if this lasts," he exclaimed. "The sea must be quite hot. Ah! that's better," he added, as the propellers began to revolve. "We ought to get out of this natural saucepan as soon as possible."

Just then Captain Restronguet's voice was heard at the telephone inquiring if Mr. Hythe were in the conning-tower.

"He is, sir," replied Kenwyn.

"Ask him to step this way. The watertight doors are now open."

"Have you noticed the sudden rise of temperature, Mr. Hythe?" asked the captain when the sub reached the fore conning-tower. "You have? I thought you would. We've had a most unusual experience; we have passed almost over the mouth of a submarine volcano at the moment of an eruption. The 'Aphrodite' was almost drawn into the vortex caused by the rush of water to fill the cavity formed by the expelled lava from the crater."

"I wonder if another island has been created, sir?"

"If there has been the 'Aphrodite' has narrowly escaped being left high and dry upon it, Mr. Hythe. It was in the last century that an island suddenly appeared almost in this latitude and longitude. The British, I believe, claimed it and so did the Italians; but before the question of ownership was decided the island settled the matter by disappearing. If----"

"Look ahead, sir!" exclaimed the quartermaster in horrified tones.

The water was now slightly less smoke-laden, and the two for'ard search-lights made a tolerable clear path for nearly a hundred yards ahead. Into that double ray of light came the hull of a sinking vessel. It was sinking stern foremost with a slight list to starboard. Hythe recognized the type of craft, a Sicilian fishing-boat. Her mast had snapped off about three feet above the deck, while her lateen sail, extended by the upward tendency of the wooden yard was almost as rigid as a sheet of metal. Lashed to the tiller was the helmsman--a dark-skinned, curly-haired Italian. The sub could even distinguish his gold ear-rings. The poor fellow was still struggling desperately yet aimlessly, for he made no effort to cast off the rope that bound him to his post of duty. His hands clutched wildly at the yielding water. Amidships were two other men, similarly secured, but they were evidently already drowned since they were making no attempt to save themselves.

But for a brief instant did the distressing vision last, for with a quick movement the quartermaster placed the helm hard over, the "Aphrodite" swerved, and the parallel beams shone upon a waste of unbroken water.

Captain Restronguet muttered something under his breath.

"Can nothing be done to save them?" asked Hythe.

The captain shook his head.

"Nothing," he replied deliberately. "Nothing. Had there been a ghost of a chance we would have taken the risk."

For several moments the occupants of the conning-tower stood in silence, gazing fixedly at the chaos of water before their eyes. By this time the "Aphrodite" had passed the influence of the eruption, for she no longer rolled and plunged on her submarine course.

"The danger is now over, Mr. Hythe," said Captain Restronguet at length. "Perhaps you would care to resume your bed? I am afraid that everything is in a fearful mess 'tween decks, though."

"It is lucky for us it is no worse, sir. For the moment I----"

A dull thud upon the deck of the submarine caused the sub's remarks to remain incompleted. The shock literally caused the "Aphrodite" to reel.

"Bring her up, sir, bring her up!" exclaimed Devoran's voice at the telephone. Captain Restronguet did not wait for an explanation. Ordering the quartermaster to trim the horizontal rudders he himself pressed the lever controlling the emergency ballast tanks. Up rose the submarine, though not with her accustomed rapidity, and soon she was pounding sluggishly in the still agitated sea that swept her fore and aft and washed over on all sides.

"A craft of sorts has foundered right on top of us, sir," continued the chief officer. "There are men still alive in her--or, at least, I fancy so."

Captain Restronguet and Hythe waited to hear no more. Leaving the conning-tower in charge of the quartermaster they rushed off to where Devoran was stationed. The fore-scuttle of the rearward conning-tower was obstructed by the bulky quivering hull of a large fishing-vessel. She was lying on her port bilges, her keel being wedged in between the deck and the base of the conning-tower, but so insecure was her balance that every movement of the "Aphrodite" in the furious sea threatened to slide her once more into the depths.

"Are the men still there?" asked Captain Restronguet.

"They were, sir, when she settled on our deck."

The sound of the concussion had brought the rest of the crew aft, and in a crowd they stood at the foot of the steps leading to the tower. The captain leant over the circular aperture and hailed them.

"Men," said he, "who will take the risk and venture outside?"

A dozen voices replied in the affirmative, even that of Gwennap, the non-swimmer.

"You, Polglaze, and you, Lancarrow. A couple of life-lines there, and two men to tend them."

Quickly Polglaze and Lancarrow sprang up the ladder and entered the conning-tower.

"There's a boat or small craft lying across our deck," explained Captain Restronguet. "I believe there are some of her crew still aboard. I want you to investigate, and should there be any men bring them back."

Deftly the two members of the "Aphrodite's" crew secured the life-lines round their waists. Devoran unlocked the lid of the aperture in the conning-tower. As the hatch opened a wave burst through, flooding the floor to a depth of two inches--the height of the coaming round the trap-door leading to the Number Two Platform. Before a second wave had time to add to the mischief already Polglaze and Lancarrow were battling their way up the shelving, slippery sides of the stranded vessel. To gain her deck there were no other means, for her keel extended far beyond the side of the submarine. Twice Lancarrow slipped, but aided by his companion, who was already astride the fishing-boat's shattered bulwarks he succeeded in scaling the wall of wood.

Just then a heavy sea came inboard. The wrecked craft rocked, seemed on the point of lurching once more into the depths, when a correcting heel of the "Aphrodite" saved the situation and the lives of the two heroes.

Peering through the almost closed hatch Devoran and Hythe saw Polglaze slide down the boat's hull, grasping what looked like a bundle of clothing in his arms.

"Keep a strain on the life-line," ordered the chief officer. "Smartly now--haul away."

Another sea flooded the deck and swirled past the base of the conning-tower. The strain on Polglaze's life-line was enormous, but fortunately the rope was a sound one. As the smother of foam subsided Polglaze's face appeared at the almost closed hatchway.

"Here you are, sir," he exclaimed breathlessly. Hythe and the first officer instantly opened the lid, and the bundle--the body of a boy about ten years of age--was thrust into their arms. Ere another wave hurled itself upon the rescuer Polglaze was safe within the conning-tower.

And now Lancarrow's burly form appeared sitting astride the fishing-craft's bulwarks. He evidently had a weightier burden, for in spite of his efforts the powerful Cornishman could not at first raise it clear of the sides. Thrice he essayed the task and the third time was successful. His burden was the padrone or master of the wrecked craft.

Just then a formidable sea, higher than the rest, came hissing and foaming down upon the submarine. Lancarrow with his back turned to it was unaware of the danger, but both Hythe and Devoran saw it and shouted a warning. Their voices were drowned in the howling and shrieking of the gale.

With a smother of hissing foam the wave burst. Lancarrow, still grasping his burden, was hurled from the bulwarks and thrown upon the "Aphrodite's" deck. The same wave sent the fishing-boat back into the depths, thus depriving Lancarrow of the slight shelter hitherto afforded by the hull, and hurled him across the slippery deck. Fortunately he was not stunned by the impact and did not relinquish his hold of the man he had rescued, while the life-line saved both from being washed overboard.

Realizing the danger Hythe fastened round his own waist the rope that Polglaze had cast off, and bidding Kenwyn and Devoran to open the hatch, he dashed to the aid of the rescuer and rescued.

Another wave flung him back just as he was on the point of gripping Lancarrow round the chest. The rush of water swept all three against the conning-tower. The slack of the life-lines were hauled in, and the receding water left them close to the hatchway.

"I've got him," spluttered the sub, as he laid hold of the unconscious Italian. "You look after yourself, Lancarrow."

With a heave Hythe lifted the padrone within reach of those within the conning-tower, the Cornishman followed, and by a display of remarkable yet undignified agility the sub succeeded in gaining safety ere a tremendous breaker hurled itself in vain against the massive metal plating.

The "Aphrodite" was quickly submerged to a depth of nine fathoms and driven ahead at a modest seven knots, while steps were taken to restore the rescued man and boy to life. It did not take long for the latter to open his eyes, but in the case of the old man three hours of unremitting toil failed to give any sign of success. More than once Hythe shook his head doubtfully, but Captain Restronguet had no intention of admitting defeat. As fast as one of the operators showed signs of fatigue another took his place in their efforts to restore the action of breathing.

After exactly three hours and ten minutes' steady work the old Italian showed signs of respiration.

"We've managed it," exclaimed Kenwyn joyfully, in the tone of a man who has fought a hard struggle and has won the victory.

"Avast there!" ordered the captain to Gwennap who was still pressing and relaxing the pressure on the patient's body. "Watch him carefully."

But in less than a minute the natural breathing ceased, and the efforts to restore respiration had to be renewed. It was not until half an hour later that the padrone was able to be put to bed and allowed to sleep, Kenwyn and Hythe volunteering to stand by and keep a watch over the patient.

It was now daylight. The fury of the waves had abated, and only a long sullen roll served as a reminder of the terrific agitation of the sea a few hours previously.

Captain Restronguet, therefore, decided to bring the "Aphrodite" to the surface, so that the loss of time during the period when the submarine was in the zone of the volcanic disturbance could be made good.

"The deck looks different to me, sir," remarked the quartermaster when Captain Restronguet entered the conning-tower. "I've noticed it ever since it grew light."

"How do you mean different?" asked the captain going towards one of the scuttles. A moment later he shouted to the chief officer.

"Hurry up and open the fore-hatch, Mr. Devoran, if you please. We're in for a run of bad luck, it seems."

Well might Captain Restronguet exclaim thus, for instead of the protective garb of light absorbing metal the submarine from stem to stern and from the top of the conning-tower to the keel was as black as a lump of coal.

CHAPTER XVII.

THE RESCUED ITALIANS.

As soon as the fore-hatch cover had been unshipped Captain Restronguet, accompanied by Devoran and Kenwyn, hastened on deck. Hythe, hearing the captain's exclamation, hurried after him.

The sky was now perfectly clear, the motion of the sea had almost subsided. But instead of the stinging, ozone-laden breeze a faint odour resembling that of rotten eggs seemed to pervade the air.

"H'm," ejaculated Captain Restronguet. "In spite of my faith in the high qualities of restronium the metal has played me false!"

"How so, sir?" asked the chief officer.

"It is not proof against the action of sulphur. Even now the air reeks of sulphur, and it was a sea highly charged with sulphur that the 'Aphrodite' passed through when she was in the immediate vicinity of the submarine volcano. Thus the silver in the alloy has been affected, and in place of a light-absorbing metal we have a dead-black surface."

"It is a serious look-out, sir," observed the sub.

"Serious. Serious isn't the word for it. We have lost a great factor in our means of offence and defence. We are no longer practically invisible."

"Can the defect be remedied?"

"Only by subjecting the plating to a fresh treatment, and that can only be done at our base in Sumatra. But be that as it may I mean to continue my search for the 'Vorwartz'. Possibly the margin of superiority lies with her, but, without boasting, I venture to assert that John Restronguet will prove a match for Karl von Harburg. I hope the wireless is intact, Kenwyn?"

"It is, sir," replied the second officer. "We have just tapped a message from the P. & O. liner, 'Coghlania,' seventy miles south of Brindisi."

"Anything of importance?"

"No, sir; merely on a matter of ordinary routine."

"Very good, Mr. Kenwyn. By the by, you might let me know the state of your accumulators. Have we sufficient power to take us to the Ægean?"

"I'll ascertain, sir," replied the second officer.

Before noon the man and boy rescued from the fishing-boat had recovered sufficiently to sit up. Their story was a thrilling one. Hythe's knowledge of Italian enabled him to follow the patois without much difficulty. They had, in company with seven other craft, put out of Porto Empedocle, on the south coast of Sicily. It was a fine night with a light off-shore breeze, the weather being fair. Thus tempted they ventured farther from land than they were accustomed to. Shortly after midnight a strange phenomenon was observed. The stars were shining through a blood-red haze, while a strong sulphurous odour was noticed. The superstitious fishermen, frightened more by omens than by bad weather, prepared to return homewards, but the wind died completely away. At two in the morning a strong nor'easterly breeze sprang up, which soon developed into a cyclonic gale. Hastily reducing their canvas the fishing fleet drove at the mercy of wind and wave, till after ten minutes of great peril they found themselves once more becalmed in an agitated sea. Once more sail was hoisted, in anticipation of a favouring breeze.

Suddenly the water seemed to be rent in twain. A deep trough appeared less than a hundred yards from the sternmost boat, and horror-stricken the terrified Italians found that their frail vessels were being sucked into the abyss. Then the cavity in the sea closed and instead a column of water, stones, mud, steam, and smoke was thrown up with tremendous force. The starlight gave place to inky blackness, and the next thing the padrone of the "Favarganna"--that being the name of the craft belonging to the rescued man--realized that the doomed vessel was on her beam ends. She righted, though half filled with water. The old man had barely time to lash his grandson and himself to the rudder head, ere a huge wave swept the boat from stem to stern and down in the depths she plunged.

Nor was old Beppo's awe any the less when he heard from Hythe of the manner of his almost miraculous escape. Devoutly crossing himself the Italian burst into a torrent of thanks to his preservers, and finished up by asking where they thought of landing him?

"I had thought of that," said Captain Restronguet when the sub interpreted the padrone's request. "Since there is now no real necessity for concealment, I think we might hail the first vessel we come across that is proceeding to Messina--if Messina still stands after the eruption."

An opportunity presented itself late in the afternoon. The "Aphrodite" was about two hundred miles S.S.E. of Cape Passaro, and running on the surface, when a tramp steamer hove in sight steering N.W. "We'll stop that fellow, Devoran," exclaimed the captain. "What does she look like?"

"I cannot make out, sir, she flies no ensign," replied the chief officer, after a lengthy survey through his telescope.

Still unperceived by the oncoming vessel the "Aphrodite" stood out in order to intercept her. At a request from Captain Restronguet two of the seamen shipped a light mast abaft the fore-conning-tower, and on this was hoisted the International Code signal--flags indicating "I wish to communicate--heave to."

As soon as the signal was observed the tramp's helm was ported as if she meditated flight, but ordering full speed ahead Captain Restronguet soon made it evident that the "Aphrodite" could go two knots to the steamer's one. The tramp's engines were set at half-speed astern and simultaneously the affirmative pendant fluttered from her stumpy foremast, while the Greek mercantile flag was hoisted on her ensign-staff.

"CAPTAIN RESTRONGUET SOON MADE IT EVIDENT THAT THE APHRODITE. COULD GO TWO KNOTS TO THE STEAMER'S ONE."
"CAPTAIN RESTRONGUET SOON MADE IT EVIDENT THAT THE APHRODITE. COULD GO TWO KNOTS TO THE STEAMER'S ONE."

"The 'Eleusis' of the Piraeus," announced Captain Restronguet, who was able to decipher with ease the modern Greek characters on her stern.

Gracefully the "Aphrodite" was brought to a stand-still within fifty yards of the Greek tramp, over whose red-leaded bulwarks appeared the heads of about twenty nondescripts who formed her crew.

"'Eleusis' ahoy!" hailed Captain Restronguet in stentorian tones.

"What ship's dat?" asked the Grecian master, who spoke English by reason of several years' service in the British Mercantile Marine.

"Submarine 'Aphrodite,'" replied her captain.

Evidently the fame of Captain Restronguet had already reached the ears of the master of the "Eleusis," for he gave a dramatic gesture of surprise.

"What want, eh? Me peaceful."

"So are we," rejoined Captain Restronguet. "We have just picked up a man and a boy from an Italian fishing-boat. Where are you bound?"

"Messina, Napoli an' Civita Vecchia, sar."

"Will you take these two men as far as Messina?"

The Greek hesitated. His natural cupidity, now that the submarine had shown no hostile intentions, returned.

"Can dey pay passage-monnaire?"

"Passage-money, you white-livered swab!" roared Captain Restronguet. "Is that the way you would treat poor shipwrecked mariners? Send a boat instantly, and take these people to Messina. If I fail to hear of their safe arrival from the Consul of that port I will take good care to obtain satisfaction from you on your homeward voyage. Do you understand?"

"Yas, captain," replied the fellow, thoroughly cowed. "Me send boat."

"If that Greek scoundrel had not been so jolly mean I would have paid him well for his assistance," remarked Captain Restronguet to the sub. "As it is, not a penny will he get from me. Excuse me a few minutes, Mr. Hythe?"

So saying the captain went below; but hardly had his head and shoulders disappeared down the hatchway when he reappeared.

"Would you mind coming with me, Mr. Hythe?" he asked. "I am about to give that poor fisherman a small present to set him up after his severe loss. I prefer to perform little acts of this nature in private, but since I am unable to speak a word of their lingo I realize I must enlist your services. But, please, no mention of this to anyone on board."

Upon entering the cabin in which old Beppo and his grandson were, Captain Restronguet produced a leather pouch and took from it thirty English sovereigns. These he gave to the padrone and bestowed another gold coin upon the lad, whereupon the rescued Italians' thanks were so profuse and pantomimic that their benefactor asked the sub to tell them peremptorily to "shut up."

"And let them know that the British Consul at Messina will arrange for them to have the gold changed into the national currency," he added. "Here is a note explaining that this man came by the money honestly. I think His Britannic Majesty's Consul will recognize that the signature is genuine. Also tell Beppo that he is on no account to pay the Greek skipper anything for his passage beyond a fair price for all meals supplied."

So saying Captain Restronguet strode out of the cabin leaving the sub to explain matters to the bewildered padrone, to whom the gold was a sum greater than he could hope to amass in ten years' hard toil.

"Boat alongside, sir," announced Polglaze.

Followed by Beppo and his grandson, who, radiant with pleasure, had now almost forgotten the perils they had undergone, Hythe went on deck. Here were gathered almost every one of the officers and crew of the submarine, while in a gig made fast on the "Aphrodite's" starboard quarter were four disreputable-looking Greek seamen.

The "Aphrodite's" men gave the departing Italians a rousing cheer, then as soon as the boat returned to the "Eleusis," Captain Restronguet gave orders for general quarters.

Ere the Greek vessel's propeller began to revolve the submarine disappeared beneath the surface, only to reappear on the port side of the tramp. Then, hoisting and dipping Captain Restronguet's green and white ensign, a compliment that the skipper of the "Eleusis" grudgingly returned, the "Aphrodite" resumed her voyage on her quest of the desperado, Karl von Harburg.

CHAPTER XVIII.

THE RIVALS PASS THROUGH THE SUEZ CANAL.

Four days later, with her accumulators charged to their fullest capacity, the "Aphrodite" arose from her anchorage in the Dardanelles.

During that period, although wireless messages were being received with almost monotonous regularity, no definite news had come to hand with reference to the movements of the "Vorwartz."

True, the captain of the Russian battleship, "Imperator Pavel," sent a wireless message to Sevastopol, which was in turn transmitted to St. Petersburg and thence to the world in general, to the effect that at eight a.m. on the morning of the 6th he had sighted a submarine eighty miles S.S.W. of that Crimean port. Having orders to sink the "Vorwartz" without warning, the Russian officer caused a heavy fire to be opened upon the submarine with the "Imperator Pavel's" twelve and three-pounder quick-firers. Every one of these guns that could be brought to bear--eighteen out of forty--joined in the racket, and confident of having destroyed the modern buccaneer, the Russian battleship returned to Sevastopol.

Captain Restronguet received this intelligence with mixed feelings. He had his doubts. He knew that the rapid firing of the Russian fleet was notoriously ill-aimed and inaccurate; he knew also that with a battleship in the vicinity Karl von Harburg would hesitate to bring his craft to the surface. If, however, the news was correct he was saved a lot of trouble, and was now at liberty to return to his base in the Dutch East Indies. Nevertheless he regretted, in no small measure, the fact that he had not been able to achieve the distinction of sinking the "Vorwartz" under conditions favourable to the lives of her crew.

An hour or so later the stalwart Cornishman executed a dance in his cabin, much to the astonishment of Hythe and Kenwyn who happened to be present.

The report of the captain of the "Imperator Pavel" was replied to by a demand from the Bulgarian Government to know why the Russians had fired upon one of their vessels. It appeared that a submarine had been ordered and built at Ansaldo's Works at Sestri, Italy, for the new Bulgarian Navy, and having finished her acceptance trials was returning to Varna. She was running on the surface and made no attempt to alter her course, or to act in any way that might be regarded as suspicious; but when passing the "Imperator Pavel" at a distance of two miles, the Russians greeted her with a sudden and totally unexpected volley of quick-firing shells.

The Bulgarian submarine quickly dived. According to the estimate of the Italian contractors' representative who was on board, not less than one hundred and twenty shells were fired, of which not one did the slightest damage beyond cutting away the ensign-staff.

"Those Bulgarians will make a fine business of this, Hythe!" exclaimed Captain Restronguet. "With Russia on bad terms with Austria and Germany the Balkan States can pull the Bear's tail as much as they like. And trust any of the Balkan States for that; they would draw blood out of a stone if they could. But some day the Powers will settle down harmoniously, and the successors to the Turkish Empire in Europe will have to knuckle under somewhat."

"You don't seem very partial to the Balkan States, sir," remarked the sub.

"Partial? By Jove, I wish I could be! We had a very good specimen the other day in the person of that rascally skipper of the Greek tramp. The stalwarts of ancient Greece would turn in their graves could they but realize to what depths their so-called descendants have fallen. Well, Kenwyn, what is it now? Another purposeless message?"

"I think not, sir," replied the second officer, handing his chief the latest "wireless" received on board.

This time, instead of executing a dance, Captain Restronguet very nearly lost his temper.

"That rogue von Harburg has done me very neatly this time, Hythe!" he exclaimed. "He never was in the Black Sea, that's my belief. Here's a message announcing that the 'Vorwartz' has passed through the Suez Canal."

"Surely that's impossible!"

"Well, then, there's the message. It is from an exceptionally trustworthy agent. I say, Mr. Kenwyn, just reply, will you? And ask to be kept in touch with events."

"Very good, sir," replied the second officer, withdrawing.

"I am anxious to know how a submarine could pass through the Canal without being detected and stopped," remarked the sub, who entertained grave doubts as to the authenticity of the wireless message, especially after the "Imperator Pavel" affair.

"So am I, Mr. Hythe," rejoined Captain Restronguet, who had now recovered his customary coolness of mind. "So am I, since where the 'Vorwartz' can go the 'Aphrodite can go also."

"You mean to traverse the Suez Canal?"

"By fair means, or failing that by foul. Otherwise it would mean that we have to circumnavigate the African Continent, and in the time we were so occupied what would Karl von Harburg be doing?"

Within twenty minutes of the receipt of the momentous news the "Aphrodite" was abreast of the classic Isle of Tenedos, bound for Port Said. All the while she had remained in the Dardanelles, although within a few miles of the seaport of Gallipoli, she had refrained from giving any signs of her presence. But at the moment of departure Captain Restronguet could not resist leaving his card in the shape of one of his green and white buoys on which were painted his customary compliments.

During the run across from Gallipoli to Port Said a complete text of Karl von Harburg's feat, as reported in the Egyptian Monitor, was transmitted by Captain Restronguet's agent for the information of his employer.

It was indeed a daring coup on the part of the German renegade.

Early one morning the "Vorwartz," running light, brought up between the breakwaters that, extending nearly two miles from shore, mark the Mediterranean entrance to the Canal. Here, landing a party of armed men, he took possession of the two lighthouses, and terrified the lightkeepers into submission. He compelled them to ascertain by telegraph what vessels had entered the canal during the previous twenty-four hours and what were expected. Finding that there were no armed ships between Port Said and Suez, and none within easy steaming distance of the latter port, he resolved upon the desperate enterprise of passing through at full speed. To keep submerged would mean loss of time and possibilities of running aground in the Bitter Lakes.

Thus, almost before the Canal authorities at Port Said recovered from their astonishment that a strangely-constructed vessel should have passed into the Canal at several knots above the regulation speed and without paying the customary dues, the "Vorwartz" was well on her way to Ismalia.

In the Little Bitter Lake her luck deserted her, for in attempting to pass a lumbering Dutch tramp steamer, the "Vorwartz" struck upon the sand on the west side of the Canal.

Meanwhile the telegraph had not been idle. It was rightly conjectured that the mysterious craft was that of the modern buccaneer, and a battery of Egyptian artillery had been ordered from Cairo. The artillerymen were sent by train, the route being so roundabout that several hours elapsed before the men and guns detrained at the nearest station, where they were separated by a fresh water canal and a stretch of desert from the spot where the "Vorwartz" had grounded.

It was fortunate for the 'Gippy artillery that Karl von Harburg did not possess the same potential means of offence as did the captain of the "Aphrodite," otherwise the charged shells in the limbers might have exploded with disastrous results. Eventually, after great exertion, the blacks got their guns into position and prepared to hull the helpless submarine. Just then a heavy sandstorm swept down. The breech-blocks of the quick-firers had to be promptly covered up to prevent the ill-effects of the sand upon the delicate mechanism. When the storm ceased the "Vorwartz" was once more afloat and hidden by the sand hills.

Only one course remained for the British officer in charge of the Artillery to take. That was to regain the railway and entrain for Suez, where another chance of cutting off the submarine's retreat was left. But once again the troops were foiled, for before they reached Suez, the "Vorwartz" had passed Port Ibrahim, the Red Sea entrance to the Canal.

Now was Karl von Harburg's opportunity to enrich himself with the plunder from helpless liners and merchantmen. The Red Sea was practically denuded of men-of-war. A pair of obsolete gunboats lay off Suakin. They were not capable of doing more than twelve knots, and could be regarded with contempt. A British third-class cruiser, one of the units of the East Indies squadron, was stationed at Aden, while the remainder of the squadron was at Bombay, with the exception of a second-class cruiser that could not well be withdrawn from the Persian Gulf, without the risk of allowing dangerous cargoes of rifles to be "run" by the Arab dhows that were ever awaiting their opportunity for the hazardous yet profitable business.

Upon the arrival of the "Aphrodite" at Port Said, Captain Restronguet was literally received with open arms by the harassed and distracted Canal officials. The presence of the "Vorwartz" in the Red Sea meant a far greater loss to them in due and tolls than while she was in the Levant, and even then there had been an appreciable falling off in the receipts. Without the faintest delay Captain Restronguet received permission to take his wonderful submarine through the hundred miles of artificial waterway, special facilities being granted so that no undue delay would be experienced. It was generally recognized that if anyone had the honour and distinction of ridding the seas of a danger and a pest that man was Captain Restronguet.

The "Aphrodite" made the journey on the surface and by night. She was twelve hours behind her rival. Fortunately it was bright moonlight, and aided by the powerful search-light on board and the electric arc lamps that had recently been placed on the banks of the canal, the passage was performed most expeditiously. At every town and village crowds assembled to cheer the modern magician. At Ismalia the Khedive's band, sent specially from the palace at Cairo, serenaded the "Aphrodite"; the shipping at Port Ibrahim hailed her approach with a deafening salute upon their syrens; and just as dawn was breaking the submarine, having accomplished the trip in less than seven hours, slipped gracefully under the waters of the Gulf of Suez.

Captain Restronguet's spirits rose. He was flattered with the reception accorded him by the Canal authorities. He realized that, instead of being regarded with suspicion, the world was beginning to appreciate his services to mankind.

"We'll have him right enough," he remarked confidentially to Devoran. "There's a faint tremor noticeable on the detector that cannot mean anything but the presence of the 'Vorwartz.' I have been officially informed that no Government submarine is within a thousand miles of us."

"How far do you think the vessel is, sir?" asked Hythe.

"The detector is sensitive to anything of that nature within a hundred and twenty miles, but, of course, the actual position of the chase cannot be fixed with any degree of accuracy at that distance. But as soon as we approach within twenty miles of von Harburg's counterfeit presentment of my submarine, the position of the 'Vorwartz' will be accurately recorded on the chart controlled by the electric detector."

During lunch the wireless room reported that a vessel was sending out calls for urgent aid, and in response to a request for further details came the startling news that the Dutch liner, "Noord Brabant," had been forcibly boarded by the crew of the "Vorwartz" fifteen miles due east of Wadi Jemel. Several of the Dutchmen had been wounded when attempting to resist; the strong-room had been forced, and nearly ten thousand pounds worth of gold had been removed. Not satisfied with this, Karl von Harburg discharged a torpedo at the ill-fated "Noord Brabant," which, exploding under her starboard quarter, completely flooded the after compartments. Leaking badly, for the shock had strained the water-tight bulkheads, the liner headed slowly for Sherm Sheikh, an inlet in the mainland, where her captain hoped to run her aground on the mud and sand that form the bottom of the cove.

"Here we are," exclaimed Captain Restronguet, running his finger over the chart of the Red Sea. "Ninety miles from Wadi Jemel; three hours run at our maximum speed. Keep her going for all she's worth, Kenwyn. I'll be with you in the conning-tower in less than ten minutes. Let the 'Noord Brabant' know we're on our way, and keep me informed of how she's progressing."

While the "Aphrodite" tore on her errand of mercy, Carclew was keeping vigilant watch upon the electric detector; but, to the disgust of all on board, instead of the "Vorwartz" making her presence felt more strongly the sensitive current grew more and more feeble. Was it possible, then, that the "Vorwartz" was able to attain a much greater speed than her rival, and in consequence slipping farther and farther from the doggedly-pursuing avenger?

Just as Captain Restronguet, accompanied by his guest, was about to proceed to the conning-tower, a final message came from the ill-fated "Noord Brabant"--"Sinking; are taking to the boats."

But the "Aphrodite" was not the only vessel hurrying to the rescue. The P. & O. Liner, "Persia," a magnificent internal-combustion propelled ship of 40,000 tons, that had been built to "knock spots off" the largest North German Lloyd boat on the Australian route, was returning on her maiden voyage. Warnings of the presence of the "Vorwartz" had been given her. Her cargo was a precious one; moreover she carried His Majesty's mails; but at the urgent call of distress all other considerations were set aside.

The officers of the "Persia" knew the risks they were running. It was recognized that Karl von Harburg would not attempt to attack or intercept the liner unless the "Vorwartz" were submerged, consequently the speed of the submarine would then be considerably lower than that of the liner. The "Persia" being a subsidized vessel under the recent Admiralty regulations, had a large percentage of Royal Naval Reserve officers and men in her crew; she was armed with light, quick-firing guns, and, in fact, was a powerful "protected" cruiser.

Owing to the danger the captain and the first officer were both on the "Persia's" bridge. Elaborate precautions had been taken to keep the news from the passengers, but, as is frequently the case, the intelligence was soon common property. That night no one went to bed; since it was within the bounds of possibility that in the event of being torpedoed by the ruthless "Vorwartz" it would be necessary to take to the boats. All lights were carefully screened; yet in spite of these preparations the "Persia" had the narrowest escape in her career.

Unseen and unheard by the officers of the watch, a torpedo discharged from the lurking "Vorwartz" glided within ten feet of her rudder. Just at daybreak the "Aphrodite" sighted the boats of the ill-fated "Noord Brabant." Towed by two motor pinnaces the life-boats, crowded with passengers, were slowly making their way northward. The "Aphrodite" had arrived in the very nick of time, for the sudden change from intense darkness to daybreak revealed the fact that three suspicious-looking Arab dhows were making ready to pounce down upon the unarmed boats.

"Red Sea pirates, by Jove!" exclaimed Captain Restronguet.

"Certainly looks like it, sir," replied the sub. "It's a curious fact, but our cruisers systematically search every little harbour on the Arabian coast and find nothing beyond a few dhows owned by Arab traders whose papers are quite in order. But once let a vessel go ashore or get into difficulties, armed dhows, manned by cut-throat Arabs, gather round like flies about a honey-pot. Goodness only knows where they come from."

"I'll tell you where they'll go to if they don't pretty soon sheer off," rejoined Captain Restronguet grimly.

"Are you standing in pursuit, sir?" asked Devoran.

"Impossible under present circumstances, Mr. Devoran. Look, those motor-boats cannot make headway against wind and sea. They have too much to tow. Another hour will see the whole swarm of boats smashed to firewood unless we do something."

The "Noord Brabant's" boats were indeed in a perilous position. Those provided with oars were two overcrowded to allow the rowers to materially assist; waves were repeatedly breaking over the deeply laden boats, and every available article that could be used as a baler was pressed into use. All the while the flotilla was slowly drifting shorewards, the rearmost boats being almost inside the broad expanse of broken water.

Bringing the "Aphrodite" head to wind Captain Restronguet ordered a heavy grass warp to be veered out by means of a barrel. This one of the motor launches secured and made fast, while the second slipped half of the boats and transferred them to the care of the first towing craft. With a reduced number of boats in tow the second pinnace was then able to make headway.

"Easy ahead!" ordered the "Aphrodite's" captain, and with a long string of boats straining at the hawser the submarine, still on the surface, forged ahead.

"Steady, sir," ejaculated Kenwyn. "We're pulling them under."

Such was the case. The speed of the "Aphrodite" was sufficient to cause sheets of solid water to fly over the bows of the Dutch boats. To reduce speed was impossible, since that would have meant a backward movement on to a lee shore.

"Have we any oil to spare on board?" asked the sub.

"We might manage a barrel of lubricating oil," answered Captain Restronguet. "A good idea of yours, Mr. Hythe."

To attempt to hoist a heavy barrel of oil with the "Aphrodite" rolling like a barge would be hazardous both to the barrel and the men engaged in sending it up the hatchway. Accordingly the barrel was tapped and the centrifugal pump, worked by one of the auxiliary motors, threw the heavy oil over the side. Soon, instead of a turmoil of white crested wind-swept waves a broad belt of sluggishly heaving water trailed in the wake of the "Aphrodite," and through this patch of comparatively calm sea the boats of the "Noord Brabant" were towed in safety.

Long before the barrel of oil was exhausted the flotilla was clear of the broken water close to the land, and the risk of being swamped was reduced to a minimum.

"Now what's to be done," asked Kenwyn of Hythe, as the two stood on the wake of the after conning-tower watching the procession of boats. "We must return to Port Ibrahim with this little mob, I suppose?"

"If we do we'll have our work cut out," replied the sub. "As soon as we make for that port the wind will be broadside on, and the boats will again be in danger of swamping. All the oil we have on board would not save them, since it would drift to lee'ard. No, the only way I can suggest--and Captain Restronguet is apparently of the same opinion--is that we plug head to wind until some vessel comes along and picks up the survivors."

Just then the "Aphrodite's" wireless picked up a general message sent out by the "Persia" to the effect that she was going at full speed to the scene of the disaster.

Captain Restronguet's face lighted up when he heard the good news.

"We shall now have a free hand," he remarked. "But at the same time it is a mystery to me how our detector has failed to record the presence of the 'Vorwartz.'"

"Perhaps she has cleared off due south, while we are heading due west," suggested the chief officer.

"That is the only explanation, Mr. Devoran. It is five hours since the apparatus, sensitive enough in all purpose, has recorded any movement. Well, Carnon?"

"'Persia' in sight, sir," replied the quartermaster, who had taken up his position, telescope in hand, on top of the fore conning-tower.

"Capital!" exclaimed Captain Restronguet. "She'll be close alongside within half an hour. Pass the word to the leading boat, Mr. Devoran, and tell them to stand by ready to cast off."

Rapidly the "Persia" approached, then, laying-to to windward of the string of boats, waited for them to be towed under her lee. Boat after boat discharged its band of passengers, the empty craft being turned adrift, and within half an hour of the liner's arrival five hundred Dutchmen had found shelter under the Blue Ensign.

Great though the attention was towards the rescued men the chief object of interest to the British passengers and crew of the "Persia" was the strangely unfamiliar outline of the "Aphrodite." Much had been heard of the mysterious submarine, the avowed rival of the piratical "Vorwartz," and now the liner's people had a unique opportunity of viewing her at close quarters.

When the work of transferring the rescued Dutchmen was completed Captain Restronguet took off his cap and saluted the captain of the huge liner. Simultaneously a tremendous burst of cheering came from throats of hundreds; and with the echoes of the prolonged chorus of welcome and approbation ringing in their ears, the crew of the "Aphrodite" quietly yet majestically disappeared beneath the waves.

CHAPTER XIX.

STRUCK BY LIGHTNING.

"It's a jolly fortunate thing that we fell in with the 'Persia,'" remarked Kenwyn, within two hours of parting company with the liner. "Otherwise it would have been a serious matter with those Dutchmen in the boats."

"You are right," assented Devoran. "It is going to be dirty weather. The glass is falling rapidly."

"It will soon be over," observed Hythe. "'Long foretold, long last; short notice, soon past.' That's how the rhyme goes, doesn't it?"

"And a brute of a business while it lasts," added the second officer.

The three officers were standing on the after deck of the "Aphrodite." The submarine had again risen to the surface and was plugging away in a southerly direction on her vague quest for the unbeatable "Vorwartz." Captain Restronguet remained below, absorbed in some abstruse problem.

The sea was smooth, but dark clouds, edged with bright, copper-tinted hues, were rapidly banking up against the westerly breeze, while the rumble of distant thunder was heard at frequent intervals. Even though it was close on midday the sun's light was greatly obscured; while, on the other hand, the far away Sudan coast stood up clearly under the effect of atmospheric refraction.

There was every indication of a sharp yet severe storm.

"Are you going to submerge her, Devoran?" asked the sub.

"Not on my own responsibility," replied the chief officer. "Until the captain gives the order--ah, here he is."

"I cannot understand how the detector is acting," said Captain Restronguet, as he gained the group of officers. "I have most carefully tested the currents and examined the platinum contact breakers. The instrument seems in order, yet it records nothing of the presence of the 'Vorwartz.' It is inexplicable."

"The 'Vorwartz' is doubtless beyond the field of electrical action, sir," remarked Kenwyn.

"So I have been told before," replied Captain Restronguet with asperity. "All the same that theory will not hold good. We ought to have had an intimation of that craft's presence when she torpedoed the 'Noord Brabant.' How can you explain that?"

"Don't you think, sir, we ought to submerge the ship?" asked Devoran, anxious to change the subject. "The glass is falling----"

"There is plenty of time," declared the captain, who was evidently not in his usual easy-going humour. "It certainly looks threatening, but at this moment the sea is as calm as glass. Look at those sharks, Devoran. Vicious looking brutes, aren't they? Suppose we give the men an opportunity at rifle practice."

The captain strolled off to watch the antics of the tigers of the deep, for four ferocious-looking sharks had been persistently following the "Aphrodite" as if anticipating a catastrophe.

The chief officer, although he would much rather have preferred to make all snug and dive to a depth of seven or eight fathoms, was not a man to quibble. He made his way to the hatch-way, to call up the small-arms party. Kenwyn stood a few paces from his superior, while Hythe, unwilling to say anything that might lead to his being snubbed, remained by the after conning-tower.

Suddenly the semi-gloom was rent by a vivid flash of lightning, that played upon the metal deck and upon the placid surface of the ominous sea. A deafening peal of thunder succeeded the flash. For a moment the sub was dazzled by the glare. When he looked aft, Kenwyn was lying on the deck, a portion of the stanchions and rails were shattered, and Captain Restronguet nowhere to be seen.

Raising a shout of "Man Overboard!" Hythe took a running dive and plunged into the sea. He struck the water heavily, for the "Aphrodite" was moving at a good speed. He might very well have broken his back but for the velocity with which he executed his dive. Not till he rose to the surface did he give one thought to the dreaded sharks: it was then too late to count the risk.

Fortunately the monsters, frightened by the flash of lightning, had for the time being disappeared. Hythe struck out to the spot where the bubbles indicated the captain's position, for, winded by the shock, the unfortunate man was sinking never to rise again.

Guided by the bubbles the sub dived. Eight powerful strokes he made ere he perceived Captain Restronguet's form slowly settling towards the bottom of the sea. Four more and his left hand grasped the unconscious man by his collar.

Striking out with his right, and his unimpeded legs, Hythe rose towards the surface. He had been almost winded by his plunge overboard, and had had no opportunity to recover his breath. His lungs felt as if they were on the point of bursting; his temples throbbed. It seemed ages before his head appeared above the surface, and he was able to take a deep draught of the sultry air. Turning on his back he kept himself afloat, at the same time supporting the unconscious captain.

The "Aphrodite" had already lost way and was going astern; in a few minutes a dark, triangular object cleaving the leaden-coloured water attracted the sub's attention. His whole senses momentarily deserted him. He realized that a shark was approaching.

His first instinct was to abandon the unconscious man and strike out madly towards the submarine; but in a moment the temptation passed. Lashing out with his legs Hythe churned up a column of water. The shark stopped, wheeled and retreated a few yards.

Another of these dreaded fish came up, and the pair, regaining confidence, began to approach, swarming towards the two men in ever-narrowing circles.

Hythe could hear the monsters snapping their triple lines of teeth in anticipation of a meal. He kicked the more, shouting at the top of his voice in the hope that the sharks would delay close investigation until it was too late for them to consummate their intentions.

The sub had heard tales of how native divers in the Pacific, knife in hand, boldly attacked the tigers of the deep. The recollection gave him but cold comfort. True he had a knife, but he lacked the marvellous aquatic agility of the Japanese and South Sea Islanders. Moreover, directly he released his hold his unfortunate captain would sink. He vaguely argued that it was but another instance of where theory does not always go hand in hand with practice.

With a sudden rush one of the sharks dashed straight towards the horrified man. The brute turned on its back in order to deliver a terrific bite. Then, apparently seized with a sudden panic, it brought its huge jaws together with a sickening snap and darted off. It was a narrow shave; so narrow that on turning the shark had rasped Hythe's hand with his rough skin.

Finding that nothing happened to hurt it, the shark returned to the charge; as it turned on its back the sub could see right into his capacious mouth. He gazed horror-stricken, too terrified even to kick out or utter a sound. Even as he looked the brute's head was literally shattered, dyeing the water with blood, while the sharp report of a rifle rang in Hythe's ears.

The coils of a rope hurtling through the air fell within his reach. He grasped the means of safety, yet was too exhausted to do more. Another shot, and yet another, rang out; then O'Shaunessey, leaping overboard with a bowline, passed the loop over his officer's shoulders.

"All right, sorr," exclaimed the Irishman cheerily. "Do you let go. I'll see to the cap'n, sure I will."

Pale and breathless Hythe was hauled upon the deck of the "Aphrodite." Captain Restronguet was also drawn into safety, and O'Shaunessey, without any attempt at haste, swarmed up the rope hand over hand.

Devoran and Kenwyn, handing their still smoking rifles to a seaman, hastened to where Captain Restronguet was lying.

"Is he dead?" asked the second officer.

"I am afraid so," replied Devoran gravely, then as the first blast of the approaching storm thrashed the hitherto placid water into sheets of foam he added:--

"Take them below. Secure the hatches. All ready, Mr. Kenwyn."

Gliding serenely deep beneath the surface the "Aphrodite" pursued her way, regardless of the storm that was now raging fiercely overhead. Flash after flash of vivid lightning played upon the angry water, the glare being plainly visible through the glass scuttles of the conning-towers, while the deep roar of the thunder literally shook the heavy metal structure of the submarine.

Gathered around the still unconscious form of the captain were Hythe, Devoran, Polglaze, and Mylor the second quartermaster, while without the cabin, anxiously awaiting the latest news of their leader, were all the crew who were not actually on duty.

Kenwyn was at his post in the after conning-tower, Lancarrow in the fore conning-tower was entrusted with keeping the "Aphrodite" on her course, while Carclew was stationed at the electric detector in order to catch the first intimation of the return of the "Vorwartz" to within the range of that instrument's action.

As soon as Captain Restronguet had been undressed the effect of the lightning stroke was apparent. From the nape of his neck to the lower rib was tattooed the image of part of the chain rails and the head of the stanchion. Whether the damage was merely superficial or whether the spine had been affected was still a matter of conjecture. His face was pale and pinched, his wide-open eyes dull, his pulse almost imperceptible. Only by holding a glass close to his mouth was Devoran able to pronounce that his chief was still alive, for there was absolutely no signs of respiration and circulation.

By careful treatment, and by giving the patient small doses of stimulants, the anxious men succeeded in bringing back the colour to Captain Restronguet's wan cheeks. The pupils of his eyes began to dilate, but although he looked at those who stood around him he gave no signs of recognition.

"You did not rescue a dead man, Hythe," remarked Devoran in a low tone. "But I'm afraid his brain is affected."

"It is too early to form a definite opinion," replied the sub, anxious to put a bold face upon the matter, although in his mind he had his doubts. "I remember on the old 'Velox,' we had a signal-man struck by lightning. He was unconscious for nearly three days; yet he recovered, and was passed for duty after a week in the sick bay."

"Yes, that's all very well," rejoined the chief officer, "but----"

A violent ringing of the bell of the "steering sentry" interrupted Devoran's remark. Both men crossed the cabin and consulted the tell-tale compass. The "Aphrodite" was fifteen degrees off her course, and the "steering sentry," an automatic instrument that gives a warning in the captain's cabin when the vessel deviates from the course set, was ringing incessantly, showing that the error in direction was a grave one.

"What are you up to, Lancarrow?" asked Devoran through the telephone communicating with the fore conning-tower. "Anything in the way?"

There was no reply.

The chief officer hailed again. Still an ominous silence.

"What's up now, I wonder," he muttered as he hastened towards the conning-tower. To his surprise he found Lancarrow huddled up on the floor, with his hands tightly clenched. Left to herself the "Aphrodite" was gradually describing a wide circle to starboard, and only the action of the automatic alarm had called attention to the fact.

Steadying the submarine on her course, Devoran shouted for a couple of hands to carry the unfortunate helmsman below. This done he told Carnon to take charge of the helm, while he made a tour of the vessel to make sure that all was in order. Devoran realized that he was now in command and that the responsibility was great. The mysterious striking down of the former steersman, whether by violence or by natural causes, could not be at present explained; but since a similar thing might happen to others who were on duty he felt it necessary that he should visit all the men at their stations and make sure that everything was in order.

Carclew was still at the detector. He had nothing to report. The instrument was as silent as the Sphinx. Kenwyn in charge of the horizontal rudders and the trimming tanks was attending strictly to his duty. He had been unaware of the affair in the other conning-tower, and since it was not his business to consult the compass and not knowing what course had been given to the helmsman, he had not remarked the erratic steering of the vessel.

"Do you think the lightning struck Lancarrow down?" asked Kenwyn.

"Bless my soul, I hope not!" ejaculated the first officer. "One affair of this sort is quite enough. Why did you ask?"

"The flashes have been terrific. They seemed to play upon the deck, even though we are nine fathoms down."

"Had Lancarrow been touched by the electric fluid it is reasonable to suppose that the electrical steering gear would be affected. As a matter of fact it isn't."

"Give it up, then," rejoined the second officer. "But how is Captain Restronguet?"

"Coming round, thank Heaven. But it's the after effects I am anxious about. By Jove! That's a flash."

It was indeed a vivid fork of dazzling blue light that seemed to corkscrew along the deck of the vessel and dart up over the for'ard conning-tower, till the submerged craft looked as if she were surrounded by a supernatural light. The phenomenon lasted only an instant, but that instant was enough for the chief officer to realize the "Aphrodite's" peril.

"BEATING DOWN, AND READY TO RAM THE APHRODITE, WAS ANOTHER SUBMARINE!"
"BEATING DOWN, AND READY TO RAM THE APHRODITE, WAS ANOTHER SUBMARINE!"

Beating down, and ready to ram the "Aphrodite" amidships, was another submarine! But its similarity to the former Devoran had no doubt as to what it was. It was the "Vorwartz."

"Hard a-port!" he shouted through the telephone to the helmsman. At the same moment Kenwyn elevated the horizontal rudders in a vain endeavour to make the "Aphrodite" dive under the on-coming attacker. It was too late. With a rending crash the knife-like bows of the "Vorwartz" crashed into the 'midships compartment of her hitherto unsuspecting rival.

CHAPTER XX.

RAMMED AMIDSHIPS.

In the captain's cabin Hythe heard Devoran shouting for the helm to be put hard a-port. He felt the vessel begin to slew round, then a crash that shook the "Aphrodite" from stem to stern, sent him and the other occupants of the cabin reeling against the starboard side.

Simultaneously the watertight doors in the two principal transverse bulkheads were hermetically sealed, save a small emergency exit from Number Three Platform to the fore compartment. Through these those of the crew who were in the holed division made their hasty escape. They were not a moment too soon, for, although the "Vorwartz" made no attempt to back out, the fracture was ragged enough for the water under great pressure to pour in cascades into the midships compartment of the ill-starred submarine.

As soon as the men were safely in the fore part of the vessel Devoran gave orders for the remaining watertight doors to be closed. He knew that, although the danger was great, there still remained a chance of saving at least two-thirds of the "Aphrodite."

"If only I had been in the fore conning-tower," he thought, "I would have given that 'Vorwartz' something to remember us by. I'll try it, though."

And calling up Carnon, who was the senior hand in the now isolated fore part, he ordered him to stand by with electrical destructors, whereby a potential charge of electric fluid could be directed upon the "Vorwartz" as soon as she had backed a certain distance from the vessel she had rammed.

In answer Carnon replied: "I've tried the gadget, sir, and there's no current on."

"For goodness' sake try the supplementary current!" exclaimed the chief officer anxiously, but the result was the same. The apparatus by which the powerful means of offence was controlled was out of order. Either the lightning or the shock of the impact of the "Vorwartz's" stem had thrown the delicate mechanism out of gear. Nor could the torpedoes be used, for the tubes, having an arc of only four degrees on either side of the bows, could not be brought to bear upon the rival submarine.

This time Karl von Harburg had scored heavily, and stood every chance of getting clear without the "Aphrodite" being able to revenge herself upon the submarine that had caught her napping.

Meanwhile the crew of the "Aphrodite," after the first shock, had taken up their stations with consummate coolness. Every man knew that the damage was great, and that the "Vorwartz" was the cause of it. One chance yet remained for them to revenge themselves upon Karl von Harburg. Directly the "Vorwartz" backed out of the rent in her rival's side, the "Aphrodite" might be able to turn sufficiently to discharge a torpedo. At the same time steps must be taken to prevent the stricken craft from sinking into depth where the pressure of the water would literally crush their as yet undamaged sections of the submarine like an egg-shell under a hundred-ton hammer.

As soon as the water in the midship section rose to the level of the centre platform Devoran gave orders for the detachable keel of that compartment to be dropped. Kenwyn touched the emergency switch, and the massive dead weight fell. Relieved of this mass of iron the "Aphrodite" lurched in an effort to rise to the surface.

The sudden strain wrenched her free of the bows of the "Vorwartz." Instantly the water, pouring through the greatly enlarged aperture, filled the whole of the centre compartment, and before the submarine had a chance to turn and let fly a torpedo at her antagonist, the "Aphrodite" sank slowly and surely.

This, although serious, was a point in her favour, for Karl von Harburg, observing with savage glee the havoc he had wrought, concluded that his rival's craft was sinking for the last time to the bottom of the Red Sea. Accordingly, satisfied that he was now free to pursue his piratical acts, since the "Aphrodite" was the only submarine he feared, he backed astern, rose to the surface, and proceeded in a southerly direction towards the Straits of Bab-el-Mandeb. Hardly a word was spoken as the "Aphrodite" sank. Devoran, his eyes fixed upon the depth gauge, was waiting his time. He, too, realized that should the submarine rise to the surface it would merely be giving her antagonist a unique opportunity of holing another of the sections that as yet remained intact. On the other hand, he had to guard against the danger of descending too far.

Thirty fathoms; the "Aphrodite" was now in total darkness as far as the water was concerned. Within the electric lamps still burned brightly, save for a few that had been shattered at the moment of impact.

"Easy ahead!" he ordered, and as the partially flooded vessel forged slowly and laboriously ahead, the chief officer trimmed the horizontal rudders so that the resistance at a certain angle just corrected the tendency of the whole vessel to sink.

Devoran set a course due east, hoping to fetch the shallower water on the African shore. Twenty minutes later he ventured to switch on the parallel bow searchlights. Even these powerful rays failed to reveal anything more than fifty miles away. Huge fish, that are rarely seen in shallow water, flitted past the thick scuttles. They made no attempt to dart out of the way of the submarine; they were blind, since the gift of sight at these depths is useless to them.

"She's standing the strain all right," remarked the chief officer to Hythe in quite a cheerful tone.

The sub nodded appreciatively. Under similar conditions on board a British submarine the state of affairs would be hopeless. With a rent amidships, extending from the upper platform to the bilges she would have sunk instantly, and given her crew no possible chance of escape; but here was the "Aphrodite" still under control and with the odds greatly in her favour. Next to Captain Restronguet, Devoran was the most capable man in whom to trust.

"Bottom shoaling!" exclaimed the sub, as the head searchlights glimmered upon an expanse of ooze, so shapeless and ill-defined that it required a practised hand to distinguish it from the deep sea.

The chief officer instantly adjusted the planes, and the submarine, though lacking her usual sensitiveness to the action of the horizontal rudders, rose steadily.

At twenty fathoms the bottom ceased to shoal, and in place of the slimy mud appeared fantastic formation of coral; a sure sign that shallower water was not far off. Again the "Aphrodite" was brought nearer the surface, till the welcome sunlight could be faintly noticed.

"Ten fathoms," announced Devoran. "This is our limit. We must carry on till we ground. Look! what a rent, by Jove!"

He pointed out of the scuttle, and Hythe following his gaze saw the fracture that the "Vorwartz" bow had caused. Her comparatively straight stem had cut nearly five feet into the upper platform of the "Aphrodite" in addition to making a vertical gash nearly fifteen feet in length in the stricken vessel's side. As a result the whole of the centre compartment had become a dead weight, and the buoyancy of the submarine being imparted only by the fore and aft compartments the tendency of the whole vessel was to sag amidships. Already the upper platform was curving ominously. It would not take much more strain to buckle the "Aphrodite." Although her steel plating was badly cracked and jagged, the restronium sheathing was severed as evenly as if made of wax. This, no doubt, accounted for the fact that the inrush of water at the moment of impact was comparatively slight, and in consequence the men stationed in the midship compartment were able to make good their retreat long before the water completely filled the space between the two principal transverse bulkheads.

"Let her down gently, Carnon!" ordered Devoran, as the "Aphrodite" passed the broad belt of coral and a clear sandy bottom was visible on all sides.

The quartermaster in the fore conning-tower knew his business thoroughly, and with hardly a bump the submarine settled on the bed of the Red Sea.

"All ready to let go?" asked the chief officer, and from the for'ard compartment came the alert reply that everything was in order.

"It is almost like abandoning one's ship," remarked Hythe.

"Hardly so bad as that," replied Devoran. "But all the same we are shedding a large portion of her. Would you mind standing by that lever, and when I give the word push it hard down. No, not just yet. We will wait and watch the fore part shake itself clear."

It was indeed a strange sight. At one moment Hythe saw the slightly buckling deck and the fore conning-tower, the upper platform, except for the fracture caused by the collision, being all in one piece. The next instant the whole of the bow compartment, including the conning-tower, gave a sudden bound and darted upwards towards the surface. Hythe could see the bulkhead with its watertight doors securely fastened, and the bright copper electrical contacts with their surrounding belt of insulated material. It reminded him of a salmon cut clean in halves.

Already the ballast tanks of the freed section were being filled, till, the upward motion checked, the structure slowly sank and settled once more in the bottom of the sea a few yards to the left of the remaining portion of the submarine. There, cut off from all communication with the still intact after part, the compartment had to remain, till, worm-like, the third section was detached from the damaged portion and united to form a smaller yet still efficient submarine.

Kenwyn had meanwhile opened the scuttle in the bottom plates of the vessel in order to guide her on her descent. Since the after portion alone possessed propelling machinery it was necessary that the fore part should be disconnected first.

"Down with it!" exclaimed Devoran, at the same time operating a switch. Hythe instantly depressed the lever as he had been instructed. The motion following the action was similar to that experienced in the sudden rising of a lift.

The damaged midship section had been abandoned to its ocean grave.

Directly the sub liberated the after portion of the vessel the hiss of the inrushing water could be heard, and, as in the case of the fore part, the surface was still several fathoms off when the upward tendency was checked.

At a few feet from the bottom Kenwyn announced that the required depth was reached, and the chief officer gave the order for "Half speed ahead."

The best engine-driver in the kingdom could not have brought his locomotive up to a train of waiting carriages easier than Devoran manoeuvred the after part of the "Aphrodite" up to the fore compartment. There was no perceptible shock, in fact nothing to indicate the fact that the union had been accomplished except that telephonic communication was automatically reestablished in all parts of the reduced "Aphrodite."

Into the air locks next to each exterior bulkhead divers were quickly sent. As soon as the water was admitted into these spaces new locking bolts were passed through and secured, and within twenty minutes of being placed in position the two parts of the submarine were made one. But instead of her two hundred feet from stem to stern the new "Aphrodite" was reduced by about one third. Nearly seventy feet of valuable length had been sacrificed; but, as Devoran remarked, "It might have been worse."

"That is true," agreed Hythe. "But what will Captain Restronguet say?"

CHAPTER XXI.

CAPTAIN RESTRONGUET LEARNS THE NEWS.

For three whole days the "Aphrodite" lay on the floor of the Red Sea. Captain Restronguet was making steady progress towards recovery, but the news of the disaster had been studiously kept from him. All on board knew that sooner or later their leader must learn of the catastrophe; but every one was in favour of deferring the evil day, fearing what the consequences would be in the case of a highly strung man who was still suffering from a severe physical and mental shock.

But until Captain Restronguet did know Devoran stoutly refused to take any action in the navigation of the vessel. Nor would he open up wireless communication. It was desirable, nay imperative, that Karl von Harburg should think that his coup had been entirely successful, and on that account the danger of unauthorized news leaking out had to be strongly guarded against.

In her present state the "Aphrodite" was no better than her rival. Her state of partial invisibility was no more, her electrical detector, whereby the position of the "Vorwartz" could be determined was no longer in working order. It was mainly responsible for the dramatic appearance of the craft under Karl von Harburg's command. Her chief means of offence--the discharge of an electrical current that would detonate any explosives within a three-mile limit--had mysteriously failed; and only upon her powerful six-inch torpedoes could she implicitly rely. Nevertheless, all on board, from the chief officer downwards, had no doubts as to the issue of the struggle, even though so far things had gone in favour of the "Vorwartz." Herr Karl von Harburg's submarine must be destroyed; her power must be completely shattered; but until Captain Restronguet was in a position to once more take charge of affairs, Devoran advocated a campaign of non-activity.

Curiously enough no reason could be given for Lancarrow's sudden illness in the conning-tower. He had completely recovered before the rejoining operations of the fore and aft sections were completed, but could give no account of what had happened. He did not remember falling: for he stated that he glanced at the clock less than half a minute before the "sentry" began to ring, and up to the last moment his recollections were perfectly clear; he did not notice any particularly brilliant flashes of lightning about that time. He knew nothing till he returned to consciousness and found himself in a bunk in the fore part of the submarine, whither his companions had carried him when the men's quarters were flooded after the collision.

On the other hand Captain Restronguet was aware that he had been struck by lightning, although he had no recollection of falling into the sea. The story of how he had been rescued at the risk of the sub's life had been told him, and his gratitude was expressed by grasping his rescuer's hand. Not a word was exchanged between them on the subject, but the action was worth volumes of words.

"How are we progressing, Devoran?" asked the captain, on the morning of the fourth day of the submarine's sojourn on the bottom of the Red Sea. "Any indication of the presence of the 'Vorwartz,' eh?"

Devoran hesitated. It would be a nasty shock to have to confess that the progress was nil and that the presence of the rival submarine had been very pronounced.

Captain Restronguet looked up sharply. He saw the chief officer and the sub exchange significant looks.

"You have a pleasant surprise for me, then?" he continued. "I'll get up and find out for myself."

"But, sir----" began Devoran. The captain stopped him by an emphatic gesture.

Hythe never felt more uncomfortable. He would right willingly have given a month's pay to be out of the business.

Drawing a great-coat over his sleeping-suit Captain Restronguet walked out of the cabin. Hythe and Devoran looked at each other and by a common impulse followed.

At the end of the alley-way terminating at the watertight transverse bulkhead Captain Restronguet stopped as if he were about to ascend to the after conning-tower; but changing his mind he opened the watertight door. One glance was sufficient. Instead of the midship compartment he was looking down the passage of the fore part of the ship.

"Well, Devoran, we've had a mishap, I see," he remarked in a casual tone.

"Yes, sir; a very unfortunate----"

"But at the same time unavoidable accident, Devoran. Of that I feel sure. No, no, there is no need to apologize. If ever a man would do his best to save the situation, that man is my chief officer. But how did it occur?"

In a few words Devoran told the story--a plain unvarnished statement of actual facts, while Hythe stood mutely by, marvelling at the captain's calmness at the news.

"I am not surprised, Devoran," continued Captain Restronguet. "Not in the least. I had a presentiment that Karl von Harburg would score at one time. Besides, have I not prepared for such a contingency by providing three distinct compartments to the 'Aphrodite'? But after von Harburg's success my counter-stroke will hit the harder. I know it, Devoran. I feel certain that we shall score in the long run. Were any men lost or injured in the collision?"

"No, sir."

"Thank God for that!" ejaculated Captain Restronguet fervently. "And are all the electric circuits working properly?"

"No, sir. The detector is entirely out of gear, and so is the offensive apparatus."

"H'm, unfortunate, but we will set that right. And the wireless?"

"I have not used or tried it, sir. Until you were fit to command I preferred to remain here and make no communication whatsoever."

"An excellent policy, Devoran. Unfortunately we must resume our wireless communications otherwise we are in the dark as to the movements of the 'Vorwartz.' But our Highgate operator is to be implicitly trusted, and if all messages are sent in code it matters little whether they are picked up by other ships or stations. Get Kenwyn to send a message asking whether any news of von Harburg has been received, and let me know directly you have a reply. I am going to my cabin now. I want to be alone. But do not feel anxious on my account. I shall be perfectly fit for duty in a very short space of time."

"Didn't he take the news calmly?" remarked Hythe after Captain Restronguet had gone back to his cabin. "It was enough to drive a fellow off his head."

"It's his way," said Devoran slowly. "It is his way. Reverses that are seemingly overwhelming and would be so to almost every one else, only spur him to renewed activities. Believe me the fun is now about to commence."

Within an hour and twenty minutes of the despatch of the wireless message to London a reply was received that threw considerable light upon the movements of the modern buccaneer.

Karl von Harburg had caused a report to be sent to the news agencies to the effect that he had destroyed the only submarine that stood between him and his definite aim, and now he was at liberty to do what damage he wished to the naval and mercantile fleets of the world, irrespective of nationality or any other consideration. With this object in view he had sunk a French liner off Cape Guadafui, after ransacking her strong rooms. He had even been compelled to substitute gold ingots for the common metal ballast of his craft. Silver he would hardly look at.

This ultimatum was received with amazement and in dismay shipping circles. It seemed in vain to appeal for armed warships to destroy the "Vorwartz," since she could keep below the surface for days at a stretch, and could descend deeper than any submarine with the exception of the "Aphrodite." And Karl von Harburg believed that his rival was no longer in existence.

There was no doubt that Karl von Harburg was a madman. However successful his raids on shipping might be, however great his hoards of ill-gotten gold, he would never be able to make use of his wealth. He was a world-wide pariah. No civilized country would give him refuge. Even his base in the Island of Sumatra was closed against him, for the Dutch officials, aroused out of their customary lethargy, had seized his concession and had taken strong measures to prevent his return.

Thus, with a crew composed of renegade Germans, Dutchmen, Malays and Chinese, he was compelled to keep to the limits of his submarine until his career of wanton destruction was brought to a close either by an act of God or the missiles of one of the avenging craft that were ever on the look-out to rid the seas of a scourge.

Meantime Karl von Harburg was directing his attention to the Somali and Zanzibar coasts. Here he could, with little risk, replenish his stock of provisions, while he was within easy distance of the recognized tracks of vessels trading on the East coast of Africa.

"So our sphere of operations is pretty well defined," remarked Captain Restronguet when the message was brought him. "It is not altogether to my liking, for I have some unpleasant recollections of the Somali coast. Not quite so bad as the West Coast, of course, but quite bad enough."

"You have already visited this coast in the 'Aphrodite'?" asked the sub.

"No; it was in a tramp steamer. We were trading, and instead of getting a profit for the owners we lost half our crew by fever and the bulk of our cargo was seized by the Arabs. That was some years ago. The fever is still there, and no doubt the predatory instincts of the Swahilis and Somalis are as strong as ever. But in a submarine things may be very different."

Once more the quest was resumed, the "Aphrodite" keeping on the surface except when a passing vessel was sighted. As secrecy was an essential point Captain Restronguet took no risks, and the submarine was submerged several times during each day.

Early opportunity was taken to thoroughly overhaul the detector, and on taking the sensitive gear to pieces the fault was discovered. It was caused by a thin strand of the insulated copper wire protruding from the amalgam covering and thus setting up a short circuit. In a way that was a matter for congratulation, as it showed that the defect was no way due to magnetic disturbances caused by the heavy thunderstorm, as Captain Restronguet fully expected it to be.

On the other hand the apparatus controlling the potential current of electricity that could instantaneously destroy a hostile vessel by detonating her powder was for the time being beyond remedy. This was a grave business, but the belt of electric fluid that rendered the "Aphrodite" immune from torpedo attack was still in an efficient state. Had the current been in action when the "Vorwartz" rammed her rival the effect would have been fatal to the former, since, herself a huge torpedo, the submarine would have spontaneously exploded.

Shortly after rounding Cape Guadafui the "Aphrodite" once more came in touch with the "Vorwartz," the detector indicating that the latter was within eighty miles. Two hours later Kenwyn, who was keeping watch on deck, reported that he heard the distinct sound of small arms firing.

Captain Restronguet, Devoran, Hythe, and several of the crew were on deck as soon as they heard the news. The sound was apparently coming from a place about twenty miles to the west.

"That's nothing to do with the 'Vorwartz,' sir," suggested the chief officer.

"I am not so sure about that," replied the captain. "It may have some connexion with that scoundrel Marburg's villainies. We will run in and see what is amiss."

"Submerged, sir?"

"No; on the surface. Time and speed are to be considered."

As the "Aphrodite" came in sight of the coast--a low-lying expanse of sand dunes fringed with a belt of milk-white surf--the hull of a large vessel could be distinguished. Ere long those on the submarine made out that the ship was aground and was heeling at a dangerous angle. She was funnelless, being driven by internal combustion engines. Her masts were still standing, though threatening to go by the board as each sullen roller thrashed against her lofty sides.

Hoisted half way to her mainmast head was the Red Ensign--upside down--as a signal of distress.

Barely two hundred yards to starboard of the stranded vessel was a break in the line of surf and a corresponding break in the coast-line, where either a river gained the sea or the sea formed a narrow inlet. Drawn up on shore at the point formed by the entrance to the creek were three ship's boats, while a quantity of boxes and casks, apparently thrown overboard from the wrecked vessel, fringed the beach.

On a sandy hillock, standing well apart from the rest of the dunes and within fifty yards of the inlet, were several men in European clothes, who, kneeling behind a shallow embankment of sand, were firing at a foe invisible to the crew of the "Aphrodite."

Three or four had been hit, for they were lying on the sand to the rear of the defences, while, judging by the smoke and the louder reports, the crew of the stranded vessel were being attacked by a far more numerous body of men armed with rifles firing black powder.

"Arabs!" exclaimed Devoran laconically, without removing his binoculars from his eyes.

"Or Somalis," added Captain Restronguet. "Clearly we are in the nick of time, for as soon as it gets dark those fellows will rush the seamen and massacre every man-jack of them."

Hythe could not help wondering how the crew of the submarine could render any effective assistance. The canvas boat had been lost in the encounter with the "Vorwartz," since it was stowed under the midship hatchway.

Captain Restronguet touched him on the shoulder.

"Mr. Hythe, you have had experience with landing parties. I have had none. Will you, then, take charge of our automatic quick-firer? I am sending it ashore with nine men."

"Very good, sir," replied the sub unhesitatingly, although he was still at sea as to how the men could be landed.

"Blow all the ballast tanks!" ordered the Captain. "A leadsman for'ard."

Then the sub realized the plan of action. Captain Restronguet was going to take the "Aphrodite" across the bar.

With no more ballast than the two sections of iron bolted to her keel for use in emergencies, the "Aphrodite" drew but five feet for'ard and seven aft. The first soundings gave four fathoms: soon the depth decreased to three.

Yet unhesitatingly Captain Restronguet held the "Aphrodite" on her course, heading towards the smooth patch in the line of breakers that marked the entrance to the creek.

Suddenly the submarine gave a jerk that almost capsized every man on deck. She had stuck right in the centre of the bar, with threatening breakers only a few yards off on either hand.

Simultaneously came a hail of bullets from the opposite bank to which the crew of the tramp steamer were holding. A strong body of Somalis, seeing the helpless state of the "Aphrodite," had commenced to direct a heavy fire upon the stranded submarine.

CHAPTER XXII.

BESET BY SOMALIS.

"Take cover!" ordered Captain Restronguet calmly. "Down below, every man."

The order was promptly obeyed, for several of the leaden messengers were flying perilously close, some impingeing upon the metal sides and conning-towers, that offered a huge target.

"It is as well we afford those rascals something to fire at," he continued, as he entered the fore conning-tower and closed the scuttles on the starboard side. "Otherwise they would be firing into the rear of the position on shore. Serve out the rifles, Mr. Devoran. We must drive them off before we can attempt to land."

So saying the captain ordered full speed astern. For quite five minutes the twin screws ran at their greatest rate, causing the hull to vibrate and the sea to be discoloured with mud and sand churned up by the action of the propellers. Then, with a rasping sound, the "Aphrodite" glided off the bank and gained the slightly deeper water.

"Easy ahead!" This time the submarine was headed slightly to the left of the spot where she had just stranded. Another dull shock told all on board that once more she was held up, this time by her keel.

All the while bullets were flattening themselves against the submarine's plating, but in spite of the danger Hythe thought of something which he immediately put into action. Grasping the lead line he gained the upper platform, ran forward and made a cast. The lead touched bottom at twenty feet.

A bullet cut a gash through the sleeve of his coat, another grazed his shoe, but grimly the sub stuck to his task. Gathering in the line he made his way amidships and made another cast. Here the sounding gave ten feet. He had learnt enough.

"We're nearly over the bar, sir," he exclaimed, as he rejoined his companions in the fore conning-tower. "If we gave her full speed ahead I think she would do it. We're in quite deep water as far aft as the after conning-tower."

Without a word in reply Captain Restronguet telegraphed for full speed ahead. With barely ten seconds' hesitation the "Aphrodite" slipped over the bar and started off up the creek at a great speed till the motors were reversed. Losing way she brought up abreast of the sorry defences held by the shipwrecked crew.

"Here we are, then," exclaimed Captain Restronguet. "But how are we going to get out again? However, that problem can wait. All ready, Mr. Devoran?"

Under the fore hatchway every available man was waiting, armed with automatic rifles. The field gun was dismounted, in order to facilitate its transport ashore, tackles being in readiness to hoist it on deck. Up the hatchway the men swarmed, and taking advantage of every bit of cover afforded by the base of the conning-tower and other projections on deck, opened a rapid, well-aimed fire upon the Somalis.

So intent were the Englishmen on shore with the work they had in hand that hitherto they had not noticed the arrival of the "Aphrodite," but with the rattle of musketry so close to where they stood they could not fail to notice that help was at hand.

With a ringing cheer the shipwrecked men redoubled their fire, for hitherto they had been compelled, except when it became necessary to repel a rush, to husband their cartridge supply.

Soon the volleys from the submarine's deck became too much for the liking of the Somalis. The accurate fire bowled dozens of them over like rabbits, and the rest promptly bolted for the shelter of the sand-dunes, whence they began to work round to join their forces with their brethren on the other side of the creek, where the chances of sending a score of unbelievers to perdition were considerably greater.

Turning the "Aphrodite's" bows towards the shore Captain Restronguet ordered easy ahead till her forefoot grounded on the stiff clay soil that formed the banks of the creek. Polglaze and Mylor immediately jumped overboard, the water reaching almost to their chins, and walked ashore, dragging the end of a three-inch rope. This they fastened to a bolt passed through a hole in the forefoot of one of the stranded vessel's boats, and the "Aphrodite" going astern pulled the ponderous wooden craft down the beach into the water.

As soon as it was brought alongside the field gun was placed into it in sections. The gun's crew, under Hythe's orders, followed, and the boat was hauled ashore by Polglaze and Mylor, who had taken the precaution to bend a rope to the painter.

Although lacking the dash that characterizes the British bluejacket, the men of the "Aphrodite" ably supported their young commander; and Hythe was surprised at the resolute bearing of the submarine's crew immediately under his orders.

The moment the boat's keel touched the ground the brave fellows heaved the heavy portion of the gun over the side and upon the beach. In twenty-five seconds the wheels were placed upon the axles and the lynch-pins thrust home. The gun, its muzzle protected against damage by a piece of stout canvas, was raised in an almost vertical position by means of ropes and levers, while the carriage was backed close to the heavy steel cylinder. Then, with a crash, the gun was allowed to drop into its proper place, and within a minute the quick-firer was "assembled" and ready for action.

Up the soft, sloping sand dunes the men raised the gun, Hythe himself staggering under the weight of a wooden case filled with projectiles. Wheeling, the men brought the muzzle of the powerful weapon to bear upon the foe, and the first of the belt of shells was placed within the breech-block.

The "Aphrodite's" landing party were only just in time. Already the Somalis, reinforced by those who had vainly attempted to stop the approach of the submarine, were massing for a concentrated rush upon the handful of men from the stranded merchant-vessel. Under a heavy fire of Martini and other rifles--weapons discarded by various Governments and sold by unscrupulous tenders to the fierce and lawless Equatorial tribes--nearly two thousand spearmen were advancing stealthily, till, in spite of a steady fire maintained by the British seamen, the attackers were within two hundred yards. Here they paused, then giving vent to a terrific roar of defiance, they broke into a headlong rush, brandishing their broad-bladed spears and leather shields in order to demoralize the unbelievers who had been rash enough to land on that inhospitable shore.

Hythe raised his hand. The gunner pressed home a small lever with his thumb. The belt of projectiles in the capacious maw of the automatic gun, grew shorter and shorter, while the steam from the water-jacket soon outrivalled the haze from the smokeless powder.

It was no longer a fight: it was a massacre. The sub saw the Somalis mown down as though with a scythe, till, unable in spite of their fanatical bravery, to face the hail of death they fled, leaving the ground thickly covered with dead and dying.

"Cease fire!" ordered Hythe; then, "Carry on. Search the bush away on the right. There are hundreds of the enemy lurking there."

Round swept the muzzle of the gun; up went the sight to a thousand yards. "Pop, pop, pop," went the sharp detonation of the quick-firer, till half a dozen rounds had been fired. Then came an ominous silence.

"Carry on," repeated the sub in a loud voice. "I gave no orders to cease firing."

"Can't help it, sir," replied Polglaze, who was sitting across the trail and manipulating the firing-gear. "The blessed thing's jammed."

It was indeed fortunate that the mechanism had not gone wrong during the attack, but the danger was not yet over. It was imperative that the weapon should be rendered serviceable again before the rescued crew could be taken off.

As soon as the Somalis withdrew beyond range the wearied men of the stranded vessel hastened to greet their new-comer, while the master, a short, broad-shouldered, rubicund-visaged old salt, briefly explained to Hythe the circumstances under which the vessel went ashore.

It came as no surprise to the sub to learn that the ship--the two-thousand ton Diesel engined tramp, "Iticaba"--had been chased by the "Vorwartz." Scorning to surrender, the sturdy skipper served out rifles and ordered his men to fire at the submarine as she rose to the surface to hail the "Iticaba" to heave-to. The bullets had no more effect than peas rattling on a corrugated iron roof, but Karl von Harburg lost no time in retiring to the security of the conning-tower.

The chase was a long one, and although the "Vorwartz," fired three torpedoes only one hit the mark, exploding under the "Iticaba's" starboard quarter and destroying one of her twin propellers and buckling the rudder, while the steel plating of the hull was fractured sufficiently to cause the vessel to be in a sinking condition.

Still the old skipper stood doggedly on the bridge, refusing to surrender. His one hope was to run the ship ashore in shoal water where the submarine could not follow. Ordering every available pump to be worked to its utmost capacity the "old man" still found the leak gaining, and it was a question whether the "Iticaba" would or would not founder in deep water.

Apparently the "Vorwartz" was unwilling to waste another torpedo on a ship that was already doomed; and since her rascally crew could not hope to gain any plunder from a foundering ship, the submarine sheered off and made way to the south'ard. Unmolested the "Iticaba" managed to reach the shore, and on striking was cast broadside on upon the breakers.

Being unprovided with wireless, the stranded vessel could not call for assistance; nevertheless the skipper, trusting that the sound might be heard by passing ships, fired distress guns at the stipulated intervals. Loath to abandon his command he still held hopes that with the aid of another vessel and the rent of the hull temporarily patched up, the "Iticaba" might even yet be towed off and brought safely into port.

But the heavy ground-swell soon knocked this idea out of the skipper's head. Serious leaks, apart from those caused by the torpedo, appeared, and in less than an hour from the time of stranding the forehold was flooded. The first on-shore gale would complete the work of destruction, and as there were indications of the approach of bad weather, the skipper reluctantly decided, on he representations of his chief officer, to give orders to abandon ship. Fortunately the "Iticaba," broadside on, afforded a breakwater for the boats under her lee, and after carefully provisioning and manning two whalers, a cutter and a gig, the crew pulled for the shore.

It was the skipper's intention to camp ashore till the forecasted storm had blown itself out, and then to coast southwards to Mombassa or Zanzibar; but the plan was foredoomed to failure.

A keen-eyed Somali, hearing the report of the distress signals, had ridden his fleet camel to the landward side of the sand dunes fronting the shore. He could see that a ship was ashore, and that there was a most excellent opportunity for his fellow-tribesmen to enjoy the congenial task of massacring a handful of unbelievers and pillaging their goods. He returned at full speed to the encampment, and soon eighty swarthy Somalis were ready for the shore.

With seamen's true contempt for danger the crew of the "Iticaba" had neglected to make any preparations for defence against hostile tribesmen. They knew that they were cast ashore upon a district over which the Italians exercised something less then a nominal sway, and that the Somalis were noted for their excesses upon any strangers who had the misfortune to fall into their hands. Yet they suffered themselves to be surprised by eighty savages while they were straggling inland to find brushwood to light a fire.

The crew paid dearly for their rashness. Four men fell under the keen broad-bladed spears of the Somalis. The rest contrived to form up and open fire; and finding that their self-imposed task had already cost the lives of twenty of the Faithful, the Somalis beat a retreat in order to summon the neighbouring tribes to aid them.

From north, west and south the fanatical warriors assembled, till, with numbers sufficient to overwhelm the handful of Englishmen, they advanced to the second attack.

Profiting by experience the crew of the "Iticaba" had meanwhile constructed rough-and-ready defences. They realized that they were fairly trapped, for to attempt to put to sea in open boats with the probability of encountering a gale would be sheer madness. On the other hand it was possible that they might hold out against the attackers, until either the weather became fair or means of rescue were afforded them.

"Well, the sooner we get you out of this mess the better," said Hythe, when the master of the "Iticaba" had concluded his narrative.

"Strikes me you are no better off than we are," remarked the old skipper. "There's too much sea running on the bar for you to get out. What water d'ye draw?"

The sub told him.

"Suppose you are one of those new-fangled craft--all top-sides and no draught in a manner o' speaking," remarked the "old man" bluntly.

"Well, hardly," replied Hythe smiling. "You see yonder vessel is the submarine 'Aphrodite,' of which you may have heard."

The master of the "Iticaba" looked at the sub for a few seconds, then shrugging his shoulders he replied,

"Look here, sir, I'm grateful for your assistance, but Cap'n Nick Rees isn't a man to be bamboozled. I know for a fact that that cursed 'Vorwartz' destroyed the 'Aphrodite' some days ago. I heard the news from official sources while I was lying at Aden."

"News from official sources is apt to be misleading, Captain Rees. It is in this case. That vessel is the submarine 'Aphrodite' and there is Captain Restronguet standing abaft the after conning-tower. There is no doubt but that he may be able and willing to afford accommodation for you and your crew. The quarters will be somewhat cramped, I fear. But as soon as we can get out of the creek it will not take us very long to tow your boats to Mombassa or Zanzibar as you suggested. How are you getting on, Polglaze?"

"A fair brute of a job, sir," replied the man, as, streaming with perspiration, he struggled with the refractory mechanism of the gun.

"It's lucky for us they have not persisted in the attack," observed Hythe. "All the same, there's no time to be lost. Mylor and Gwennap, will you take the boat and row off to the 'Aphrodite.' Inform Captain Restronguet of the state of affairs, and how the position will be difficult to hold in the event of a night attack. Ask him if there is any objection to bringing off the survivors of the 'Iticaba'?"

While the two men were on their errand, and Polglaze, with two or three assistants, was endeavouring to get the automatic gun into working order, the rest of the landing-party assisted the crew of the "Iticaba" to launch the ship's boats. Within an hour they were afloat and moored a few feet from the bank of the creek, stern ropes and kedges having been laid out so as to haul them off into deep water should it be necessary to embark in a hurry.

Presently the quartermaster and Gwennap returned with the order that Captain Restronguet wished the landing party and the rescued men to embark at once, as the wind was rising and there was a heavy swell tumbling in over the bar.

The crew of the "Iticaba" received the communication with mixed feelings. They were glad to leave this inhospitable shore, but at the same time they had grave misgivings as to whether they ought to trust themselves on board a submarine. The majority of the men, although members of the Royal Naval Reserve, were blue water seamen, to whom a storm at sea had no perils providing they were at a safe distance from a lee shore. They were sufficiently conservative in their ideas to regard with obvious distrust the interior of a submarine as a haven of refuge.

"Are you going to dive, sir?" asked Captain Rees. "If so, I'd rather stick it ashore and chance my luck; and most of my men would too, I'm thinking."

"Please yourself, then," replied the sub brusquely. "I wouldn't give a rope's-end for your chances if you remain here. Now, then, Polglaze, hurry up. Limber up, there, we'll finish the repairs on board."

"Nearly finished, sir," answered Polglaze remonstratively.

"Can't help it. There'll be too much of a swell on the beach in a minute. Fall in, men."

Captain Rees glanced in the direction of the "Aphrodite," which was moored by a pair of stout chain cables, since her patent anchoring device was useless when afloat. He gave another look, this time at the slender mounds of sand that had been hastily heaped over the victims of the Somalis.

"Come along, men!" he exclaimed.

Quickly the landing-party and the crew of the "Iticaba" embarked. Polglaze, still lingering longingly over his array of spanners and other armourers' tools, accompanied the gun to the beach.

Just as the gun's crew were about to unmount the heavy weapon from its carriage a blood-curdling roar of mingled yells and shouts burst from a dense body of Somalis, who, observing the embarkation in progress, had crept up the remote side of the dunes, and barely a hundred yards from the shore.

Three of the seamen who had not yet embarked dropped on one knee, and using their rifles, strove to check the furious rush. Others in the boats joined in the firing, while from the deck of the "Aphrodite" every man left on board hastened to aid their comrades with well-aimed volleys.

Coolly Polglaze attempted to adjust the small pieces of mechanism necessary to make the automatic gun serviceable, while Gwennap stood ready to thrust the end of the ammunition belt into the breech-block feeder.

The next instant Polglaze dropped limply across the trail with a broad-bladed spear thrown at less than ten yards' distance sticking into his body. Gwennap, using the butt-end of his rifle, stood over his comrade till, desperately fighting, he fell. The gun was surrounded by a swarm of blood-thirsty foes.

Seeing this the men who still remained ashore made a wild scramble for the boats, and the fire in consequence slackened. Revolver in hand, Hythe called to them to make an effort to recover the gun. The call was promptly obeyed, and a dozen men, comprising several of the "Iticaba's" crew, in addition to those of the "Aphrodite" jumped ashore, pouring in a hot fire as fast as they could handle the bolts of their magazine rifles.

Unable to withstand so concentrated a fire the horde of Somalis melted away. The gun stood alone with a score or more of corpses to bear testimony to the efficacy of the rifle-fire.

But there was no time to be lost. Already a swarm of the enemy, four or five times as numerous as the crowd that had just been driven off, were racing like furies to renew the conflict.

As soon as Hythe gained the place where the quick-firer stood he realized that it was impossible to remove it. Even in the short interval during which it had remained in the enemy's possession the Somalis had taken good care to sever and remove the drag ropes.

Calling to his men to carry off the bodies of Polglaze and Gwennap, the sub removed the breech mechanism, and staggering under the heavy weight, he followed his men to the boats, where, under a heavy but ill-aimed rifle fire from the Somalis, they pushed off towards the "Aphrodite."

Under the lee of the submarine the men boarded their haven of refuge. One glance sufficed to show that poor Gwennap was no more. The Somalis, not content with slaying outright, had hacked his body in a most atrocious manner. Polglaze still showed signs of life, for protected by his comrade's body, he had escaped the demoniacal fury of the savages. Nevertheless the spear-thrust through his left shoulder looked very dangerous.

What had to be done must be done quickly, for night was approaching, and the Somalis were evidently making preparations to remove the gun which had been left in their hands. As long as daylight lasted the rifle fire from the deck of the submarine would effectually check any attempt in this direction, while an additional deterrent was provided in the form of a powerful rocket. This could only be fired at an angle of less than five degrees from the perpendicular, and in consequence could do no physical hurt to the Somalis. Nevertheless the moral fear it inspired served to make the natives clear off to a respectful distance, where they waited for nightfall.

It was obvious that the attempt to recapture the quick-firer must be made early for other reasons. The wind was now blowing strong from the east'ard, and with the rising sea landing would be a very difficult matter; while, floating light, the submarine stood a good chance of being blown from her anchorage.

As soon as night had fallen twenty men led by Hythe fell in on the upper platform. Rifles were discarded as encumbrances, but each of the party carried an automatic pistol in his belt, the weapon holding ten cartridges, while separate clips, each containing a similar number, were placed in their ammunition belts.

Into the stern-sheets of the "Iticaba's" cutter was stowed a coil of three inch rope--the "coil" measuring the orthodox one hundred and thirteen fathoms. One end of the rope was made fast to the "Aphrodite's" for'ard capstan, while to the other end was spliced a length of flexible steel wire rope.

With muffled oars the boat's crew gave way, Mylor the quartermaster paying out the rope as the boat stole shorewards. There was little need for silence, for the thunder of the surf on the reef drowned every other sound.

All went well till the cutter grounded on the shore, then from a distance of nearly two hundred yards along the bank the darkness was pierced by the flash of the Somalis rifles, while a swift rushing sound indicated that swarms of fierce foes were charging down upon the boat.

CHAPTER XXIII.

OVER THE BAR.

Although the air seemed alive with the screech of the bullets the Somalis fired so high that not a man was hit. At the first volley Hythe ordered the quartermaster to haul the cutter off, then bringing her broadside on, he gave the word to open fire.

It spoke volumes for the discipline of the men under his command that not one of them gave way to the temptation to discharge his pistol. The pressure of a few ounces on the trigger would be sufficient to send ten shots into the mob on shore, but in the dark there was the danger of the men in the boat accidentally hitting their comrades, but until the cutter swung round broadside on, the boat's crew resisted the almost overwhelming desire to return the fire.

But Captain Restronguet had taken precautions to counteract the surprise. Simultaneously the two starboard search-lights were switched on and swung abeam till the powerful rays flashed full in the faces of the astonished Somalis. To the latter it savoured of magic. Blinded by the glare, galled by the fusillade from the automatic pistols, and harassed by the fire from the deck of the "Aphrodite" they fled. Some, however, too terrified to move, flung themselves on the ground, which was already littered with the bodies of several of their comrades.

"Give way," ordered the sub.

Directly the boat touched shore all hands save two jumped out, and carrying the rope, dashed for the gun, that now stood revealed as if outlined in silver in the rays of the search-light.

In a trice Mylor had secured the steel wire rope to the trail. A long and a short blast on Hythe's whistle was the signal that this part of the task had been satisfactorily performed.

The electric capstan on the submarine's deck began to revolve, and the heavy gun with a succession of jerks was hauled through the yielding sand.

"Avast heaving!" shouted the sub, as the recovered weapon reached the water's edge.

"Look out, sir!" shouted O'Shaunessey, and raising his pistol the Irishman shot through the head a Somali who, feigning death, had allowed Hythe to approach within three yards of him ere, springing to his feet, he was about to hurl his spear at the sub's back

"Thanks, O'Shaunessey," exclaimed Hythe.

To the accompaniment of a desultory and erratic fire from a distance of over a thousand yards the gun was dismounted and "parbuckled" into the cutter. The carriage and limber followed piecemeal, and without a casualty beyond a few bruised knuckles and jammed fingers the landing party re-embarked.

It was tricky work transhipping the gun to the submarine, for the "Aphrodite," with nearly fifteen feet freeboard, was rolling heavily. The men were working in the dark since the searchlight could not be swung from off the shore without attracting the Somalis to closer range. Even as it was chance bullets were impingeing upon the submarine's plating, while one cut a clean hole through the side of the cutter, fortunately without hitting any of the men on her.

As soon as the gun was safely housed below steps were taken to spend the rest of the night in quietness. The boats of the "Iticaba" were heavily ballasted and their bungs removed, so that they sunk to the bottom of the creek. Thus they were immune from danger from the enemy's rifle bullets, while, when occasion arose, they could easily be raised and again pressed into service.

Reluctantly the survivors of the "Iticaba" went below. The men were temporarily quartered for'ard in one of the store compartments, their comrades of the "Aphrodite" making them as comfortable as they could; while Captain Rees and his first mate were accommodated in Kenwyn's cabin, that officer having to share Devoran's quarters.

But when the "Aphrodite" settled easily upon the bed of the creek and nothing alarming occurred, the rescued men's misgivings were set at rest, and before long, worn out with fatigue, exposure, and excitement they were sound asleep, regardless of the fact that thirty or forty feet above them the seas were tumbling wildly into the exposed inlet.

Throughout the rest of the night the Somalis wasted their ammunition in firing at the position where they last saw the submarine lying, and with the dawn the anchorage was bare. Their losses were made light of, for, according to their belief, they had rid the world of a shipload of unbelievers. No doubt they were a little disappointed that there were no trophies of their victory, but they contented themselves with removing the wreckage and stores washed ashore from the ill-fated "Iticaba," which had completely broken up during the gale.

Early on the morning of the second day of the "Aphrodite's" detention in the creek the men of the "Iticaba" were surprised to see nine men, clad in air-tubeless diving-suits, make their way through the compartment which had been allotted to them.

Half an hour later the nine returned. In that half hour the remains of poor Gwennap had been buried in the sand at the bottom of the creek. Captain Restronguet would have preferred to have given his faithful comrade a sailor's grave in the open sea, but since it was impossible to say how long it would be before the submarine could recross the bar, the corpse had to be removed by a funeral party in diver's dress.

During the day the detector, which had hitherto given plenty of indications of the "Vorwartz" gradually failed to record the movement of the submarine under Karl von Harburg's command. Either the vessel had been driven ashore in a gale or else she had gone many miles to the south'ard, and beyond the field covered by the electrical rays of the detector. In vain Captain Restronguet asked for information by wireless. No news came to hand; his quest had received a check, for cooped up within the creek he was unable to gain or even keep pace with his sworn enemy.

It was not until the third day that the gale moderated sufficiently for the "Aphrodite" to rise to the surface. Her appearance was the cause of a wild stampede by the Somalis still engaged in enriching themselves with the stranded cargo. To see a vessel that they confidently believed to have sunk suddenly rise from the deep was to them incomprehensible. They fled, never stopping till they had placed a good half day's journey between them and the sea. In future they regarded the vicinity of that inlet as a district frequented by djinns, or evil spirits, and for some time to come, at least, should the crews of any vessel have occasion to land upon that inhospitable shore, they would be spared the possibilities of a fight against overwhelming numbers of fanatical Somalis.

Two more precious days were wasted after the weather had moderated sufficiently to allow the "Aphrodite" to rise. Captain Restronguet began to get anxious, for provisions were running short. A considerable quantity of "emergency rations" had been lost with the central section of the submarine, and now, with a refugee crew to feed, the vessel's resources were severely strained.

Since there was little current in the inlet it was impossible to recharge the accumulators, and the reserve of electricity had to be carefully husbanded. Fortunately fairly fresh water for drinking purposes could be obtained on shore, and thus the necessity of using the condensers was for the time being no longer urgent.

After the storm the tide fell short of its customary height, for the gale occurring at the time of spring tides, there had been an abnormal rise on the bar. Careful soundings revealed the unpleasant fact that at the top of the tide there would be only a few inches under the keel of the submarine, while, with the ground swell still breaking, this margin was quite insufficient to attempt the passage with any chance of safety.

Then news arrived by wireless that the "Vorwartz" had been operating in the Mozambique Channel, a French liner bound for the ports on the west coast of Madagascar being ruthlessly sunk. In this instance there was no attempt by the modern buccaneer to plunder his prize. Without attempting to take possession of her he had sunk her in deep water, there being barely time for the passengers and crew to take to the boats.

Furthermore, it was announced that rewards totaling nearly a hundred and forty thousand pounds had been offered to whoever succeeded in capturing or destroying the "Vorwartz." Of this amount Lloyd's--already a heavy sufferer by these depredations--had guaranteed thirty thousand, the remainder being provided by the Governments of Great Britain, France, Germany and the United States of America.

Captain Restronguet fumed at the delay. It was not on account of the bounteous guerdon, but because he was unable to put a stop once and for all to his rival's insane acts, for without doubt Karl von Harburg was now nothing less than a dangerous maniac, who possessed sufficient cunning and authority to bend the will of his crew to suit his own aims. It seemed hard indeed that a vessel like the "Aphrodite," equipped with every appliance that human ingenuity could contrive, should be penned in by a narrow strip of sand and shingle on which the surf rolled incessantly.

"I'll have a shot at it at next high water," announced Captain Restronguet to his officers. "That will be at three o'clock! It is high water full and change on this part of the coast at a quarter past four, and as there is a new moon the day after to-morrow each tide until that day ought to be higher than the preceding one."

"Unless influenced by the wind, sir," added Hythe. "That is a great consideration."

"Undoubtedly," admitted the captain. "But the sooner we make our preparations the better. Pass the word for Captain Rees, and ask him to warn his men to bear a hand. Unless every one works with a will our chances of success will be severely threatened."

The sunken boats of the "Iticaba" were raised, baled out, and laden with movable stores from the submarine. Everything that could possibly be taken from the "Aphrodite" to lessen her already diminished draught was hoisted out, till the boats were laden as deeply as they could be in view of the fact that they would also have to pass the dangerous bar.

"We had a matter of three hundred barrels of heavy oil in the old 'Iticaba,' sir," announced Captain Rees. "It's just possible that those murdering rascals have not stove in the heads of every barrel that came ashore. They might be of service in keeping down the broken water."

"Might," remarked Captain Restronguet dubiously. "What do you say, Mr. Hythe?"

"I've had no experience under circumstances like the present, sir," replied the sub. "The Board of Trade officials state that in a surf, or waves breaking over a bar, the effect of the oil is uncertain."

"We'll try it, anyhow," said Captain Restronguet. "Tell Mr. Kenwyn to take a party ashore--see that they are well armed and keep a sharp look-out--and bring back any barrels of oil that may have come ashore."

In less than an hour Kenwyn's party returned, pushing five large barrels over the sand. These were placed in the cutter, which was immediately sent seawards, for it was now nearly the time of high water. As the boat gained the fringe of breakers one wave washed over her bows. From the deck of the "Aphrodite" it could be seen that they were baling furiously. It was a question whether this cutter would escape being swamped; but after a strenuous struggle the boat succeeded in drawing clear of the surf.

Anchoring, Kenwyn prepared to liberate the oil. Simultaneously the 'Aphrodite' weighed her anchors, and with the other boats of the 'Iticaba' in tow awaited the critical moment to attempt the risky passage.

"They're staving in the barrel, sir," announced Devoran. "There's one overboard."

"It makes a difference to the water already," observed Captain Restronguet. "But we'll wait till they heave the contents of another couple of barrels overboard, and then we'll see what we can do. By Jove, what's that?"

A sudden flash, vivid even in the strong sunlight, was followed by a dense cloud of smoke that completely hid the cutter from sight. Owing to the lack of wind the vapour hung about like a pall, but presently the heads of several men could be seen as they swam for all they were worth towards the shore.

There was a rush for the boats that still remained alongside the "Aphrodite," and heedless of the risk they ran in pulling the laden craft towards the bar the crews bent to their oars.

In a comparatively short space of time the swimmers were all picked up, several of them being slightly burned, while in some instances their hair and beards had been singed off.

"What has happened, Mr. Kenwyn?" demanded Captain Restronguet, as the unlucky boat's crew boarded the submarine.

"One of the barrels contained sodium carbide, sir, and we didn't know it till the head was knocked off. There was a lot of water in the bottom of the boat----"

"And what caused it to take fire; some one was smoking, eh?"

"Yes, sir," replied the second officer.

"Was it one of my men?"

"No, sir."

"Very well, I'll say no more. Had the culprit been one of the 'Aphrodite's' crew there would be trouble; but I do not want to exercise any jurisdiction over the men of the 'Iticaba.' At the same time, Mr. Kenwyn, it was your duty to keep order in the boat, and with an inflammable cargo of oil on board, you ought to have maintained the strictest vigilance."

Kenwyn did not reply. The captain's strictures were necessary, but the second officer was not a man to make lame excuses, even though one of the seamen from the "Iticaba" had quietly lit his pipe while Kenwyn's back was turned.

The carbide had by now burnt itself out, but patches of burning oil were still drifting shorewards. Nevertheless the object of the expedition was in the main successful, for the seas no longer broke heavily, but continued in a sullen roll right into the deeper water within the creek.

Ordering half speed ahead, Captain Restronguet stood by the quartermaster and gave directions as to the course. Gathering way the submarine started on her bid for freedom, the remaining boat of the "Iticaba" being towed astern. No one remained in the boats, while at the stern of the "Aphrodite" a man stood ready with a sharp axe to sever the towing hawser should any of the lumbering craft become swamped.

Nearer and nearer to the danger zone the "Aphrodite" headed. Suddenly there was a dull thud. She was aground aft. The boats in tow came surging alongside, only to be swept backwards with a tremendous jerk on the hawser as a roller came swinging by.

That wave did it. Lifting the "Aphrodite's" heel clear of the sand it enabled the submarine under the action of her powerful engines to glide into deep water, followed by the half water-logged flotilla of boats.

As soon as a safe distance had been placed between her and the inhospitable shore the submarine eased down; the "Iticaba's" boats were brought alongside and the work of bringing the "Aphrodite's" spare gear on board again was pushed forward with feverish energy.

All the boats save the largest whaler were cast adrift, as if kept in tow they would have made a great difference in the submarine's speed, and anxious to fall in with the piratical "Vorwartz," Captain Restronguet ordered a course to be shaped for Zanzibar at the utmost capacity of the "Aphrodite's" motors.

CHAPTER XXIV.

THE AERO-HYDROPLANE.

"I want you men to promise me," said Captain Restronguet, addressing the survivors of the "Iticaba's" crew, who were drawn up in the submarine deck--"I want you to give me your word of honour that on landing, and in a period of fourteen days from that time, you will make no mention whatsoever about the 'Aphrodite' being still capable of action. Mind, I do not bind you down by conditions, threats, or intimidation of any sort. I would not insult a body of true-hearted British seamen by so doing. I merely ask, in the interests of every vessel within range of the 'Vorwartz's' atrocities, that the presence of the 'Aphrodite' should not be revealed."

The submarine was now within ten miles of Ras Nungwe, the northernmost part of Zanzibar Island, and the "Iticaba's" people were about to be sent ashore. They had, through their skipper, expressed their most grateful thanks for their gallant rescue in the nick of time, and in replying Captain Restronguet had made this request with reference to the "Vorwartz."

"Strikes me very forcibly, sir," answered Captain Rees, "that you have made a very difficult request. You see, there's bound to be an inquiry by the Consul, and a report will have to be sent to Lloyd's before the owners can recover the insurance. And without I make a clean breast of it the Board of Trade will take away my ticket."

"By Jove, I hadn't thought of that!" exclaimed Captain Restronguet. "As you say, it is a very difficult point to take into consideration. Yet in an affair of this description, where so much depends upon the issue, the ordinary routine followed in cases of shipwreck ought to be put aside, at least for a few days."

"I could answer for my men," continued the old skipper, and a lusty chorus of "Ay, ay," that had a ring of sincerity in it, came from the survivors of the ill-fated tramp. "But, you see, sir, it's a ticklish business trying to bamboozle the Board."

"If I were to write a letter to the President of the Consular Court--no, I'll tell you what I'll do; I'll go myself," declared Captain Restronguet. "Mr. Devoran, keep an offing, will you? I'm going ashore in the 'Iticaba's' boat; I'll hire some sort of craft to get back, so keep a sharp look-out for me on the west side of Bawi Island, that's over yonder. It is on the north side of the Western Pass, as the approach of Zanzibar Town is called. Should any large craft come in sight, don't hesitate to dive. We must preserve our secret at all costs."

"Are you going alone, sir?" asked Hythe.

"I did think of so doing; but why? Would you like to accompany me ashore?"

"I should, sir. You see, I know the place fairly well. Spent three months in the East Indies flagship in these waters when I was a midshipman."

The whaler was manned, Captain Restronguet, the skipper of the "Iticaba," and Hythe sitting in the stern sheets. There was no wind, so the men had recourse to their oars, and a five mile pull under a blazing sun was no light task. Nevertheless, within an hour and a quarter of leaving the "Aphrodite" the whaler ran alongside the landing-slips at Zanzibar.

A crowd of Arabs, Zanzibaris, and negroes, with a sprinkling of Europeans, awaited the arrival of the boat, for since there was no large vessel lying outside the Western Pass, it was rightly conjectured that the men were survivors from some disaster.

Loyally the seamen maintained silence, and stolidly refused to be questioned by several of the seamen from other ships that happened to be lying in the roadstead, and in a body they marched to the British Consulate, where Captain Restronguet asked to be shown into the presence of His Majesty's representative.

"What name, sir?" asked the stalwart sergeant of marines, who was in charge of the guard.

"That I wish to withhold," replied the Captain. "At the same time I am convinced that the Consul will be more than willing to see me."

The sergeant demurred, but just then a dapper little man, whose snow-white hair and closely trimmed grey beard contrasted vividly with his brick-red complexion, came across the courtyard.

"What's this? Shipwrecked men?" he asked, scanning the somewhat dishevelled crowd of seamen, some of whom bore traces of hard knocks received in the struggle with the Somalis.

"These men are," replied Captain Restronguet. "I have not had that misfortune. Neither has my friend here. At the same time I wish to make an important communication to you in private."

"By all means," said the Consul. "This way. Simmons, will you please bring whisky and soda into the small study. I presume, gentlemen, you would like a peg?"

"Now," he continued, as Captain Restronguet, Captain Rees, and Hythe followed him into the room, "what can I do for you? Do you wish to make a statement on oath? If so, I must send for my secretary."

"The necessity for making a statement upon oath rests with you," replied Captain Restronguet. "Allow me to introduce myself as Captain John Restronguet, commanding the submarine 'Aphrodite,' which is now lying off the port."

The Consul stared at his informant for quite ten seconds, then recovering himself said stiffly, "This, sir, is neither the place nor occasion for a senseless joke."

"I agree with you."

"Then, why? The 'Aphrodite' was destroyed by that villain Karl von Harburg in the Red Sea more than a week ago."

"On whose authority did you hear this, might I ask?"

"On the word--if word it can be called--of Karl von Harburg himself."

"The report was false. I am he whom I claim to be. This gentleman, Mr. Arnold Hythe, an officer of the Royal Navy, will corroborate my statement."

"I am aware that Captain Arnold Hythe was in the 'Aphrodite,'" said the Consul, who was still unconvinced. He was an old Cambridge man, and as such had both participated and had been the victim of more than one elaborate hoax. Such episodes, utterly foolish as they appear to be, serve their purpose in after life. They impart a considerable amount of shrewdness into the human mind.

"Can you offer me definite proof?" continued the Consul. "If so I should be delighted, since it is my opinion that the only vessel capable of meeting the 'Vorwartz' on anything like even terms was, or perhaps is, the 'Aphrodite.'"

Captain Restronguet bowed. "Sir, I feel honoured," he replied. "But since you cannot accept the word of a gentleman, I can offer no other solution."

"It is part of my duty to investigate matters," said the Consul reprovingly. "If I remember rightly a photograph of Sub-Lieutenant Hythe appeared in the illustrated papers at the time he was supposed to have been lost in Plymouth Sound. I cannot admit that the gentleman resembles the portrait."

"Have you a Navy List, sir?" asked the sub, speaking for the first time during the interview.

The Consul walked across the room and took from a bureau a copy of the familiar blue paper-covered book, which he handed to the sub.

"The 'Topaze' is in the roadstead," said Hythe, as he rapidly turned over the pages. "Ah, here we are. Commander the Hon. C. L. Sedgwyke, I know him, but I'm afraid he doesn't know me. Lieutenant Totterbull--h'm, yes, he might. But here's Dewerstone, he was in my term at Dartmouth. Would you mind if he were sent for, sir?"

"Certainly not. I will have a signal made at once," replied the Consul.

"You wouldn't mind, sir," continued the sub, addressing Captain Restronguet. "Dewerstone is a fellow to be trusted. He wouldn't say a word to anyone outside."

Accordingly a signal was made from the roof of the Consulate, and Sub-Lieutenant Dewerstone was informed by his captain that his presence was required ashore. The young man did not feel particularly joyful at the intelligence. He had already obtained permission to go to a tennis party, and having to attend on Consular Service did not appeal to him. Nevertheless, as soon as a boat could take him off, Dewerstone was ready.

"Good afternoon, Dick," exclaimed Hythe as soon as the sub from the "Topaze" had paid his respects to the Consul.

"Well, Hythe, where did you roll up from?" asked Dewerstone nonchalantly. "I thought you were in Davy Jones's locker."

"I am not," said Hythe earnestly. "Perhaps you would not mind proving my identity to His Britannic Majesty's Consul."

"Considering we were in the semi-final for the heavyweight and you knocked me out I think I can safely do that," replied Dewerstone.

"We need not go further, gentlemen," announced the Consul. "I must apologize for not accepting your word, Captain Restronguet. Now what do you wish me to do?"

As briefly as he could Captain Restronguet explained the circumstances under which he rescued the survivors of the "Iticaba," and the reason why he wished salient facts in connection with the affair to be temporarily suppressed.

"I think it can be arranged," said the Consul. "At all events, I will take down the depositions of Captain Rees, and omit any details I consider necessary."

As soon as this was done Captain Rees took his departure.

His men had already been quartered in the Consulate, where they were to remain until they could be sent back to Liverpool.

"You will dine with me, gentlemen?" asked the Consul of Captain Restronguet and the two subs. "There is no immediate hurry for you to get back?"

"I must get a boat before four o'clock," replied Captain Restronguet. "So I must ask to be excused."

Hythe was also unable to accept, while Dewerstone, still intent upon the tennis party, managed to find a reason for declining the stiff formality of dinner at the Consulate.

During their stay at Zanzibar Captain Restronguet and his companions visited the old town, but finding it remarkable for its malodorous nature, they beat a hasty retreat and went for a stroll inland. Before they returned it came on to blow fairly hard from the sou'west, and by the time they reached the landing-place it was pretty evident that a boat could not put off without great risk.

In vain Captain Restronguet offered the native boatmen a large sum to be rowed off beyond Bawi Island. He even tried to charter a dhow, but without success.

"We could ask the Consul to communicate with the 'Topaze' or any of the cruisers and gunboats in the roadstead; they would send a piquet-boat for us," suggested Hythe.

Captain Restronguet shook his head.

"Not if it can be avoided," he answered. "I have reasons for not falling in with your plan. We will see if we can get better luck at Shangani Point. The water ought to be smoother there."

Accordingly both men set off as briskly as they could in the moist, enervating heat, but before they had passed the Sultan's palace a short, sparsely-built man in European clothing overtook them. Twice the man looked over his shoulder at Captain Restronguet, then suddenly wheeling he intercepted him and held out his hand.

"What ho, there, Tretheway! Whoever would have thought of meeting you in this dead and alive corner of the globe?"

Hythe naturally thought it was a case of mistaken identity on the part of the little fellow, but to his surprise Captain Restronguet replied in a cordial manner.

"Bless my soul! It's Jenkins. What are you doing here?"

"It is," assented that worthy. "I've been knocking about a bit since I last worked--I mean, slaved--with you in a British dockyard. Fallen on my feet at last though, that is, unless I fall on my precious skull. Just fancy, Tretheway, I am aeroplanist-in-chief to His Highness the Sultan of Zanzibar."

"Better you than me," remarked the Captain with a laugh. "But I was unaware that the Sultan was a devotee of the art of flying."

"He is, and he isn't," replied Jenkins. "He owns a good many air crafts of various types, and I and several others, mostly Frenchmen, by the by, give exhibition flights while he sits in his state chair and watches us. But how goes it? You look jolly fit, and don't appear as if you were hard up for a dollar?"

"No, I cannot complain on that score," said Captain Restronguet quietly.

"Well, come and have a look at my little air-fleet. Really they don't make a bad show. And your friend, of course."

"Sorry," replied Captain Restronguet. "But we're in a regular hurry. I am trying to get a boat to put me off."

"Where to?" asked Jenkins. "One of the liners in the Roads?"

"No, further out; quite five miles off."

"Guess you won't get a Zanzibari to take on the job. There's a brute of a swell tumbling in. Look here, I'll tell you what: I'll give you a lift in one of our aero-hydroplanes, if you like."

"Is it safe?" asked Captain Restronguet earnestly, whereat Hythe wondered, for his companion had never before shown signs of timidity, even when in tight corners in the depths of the sea.

"Safe as a house," replied Jenkins reassuringly.

"Jenkins, my friend, you misunderstand me, although I quite admit the question was ambiguous. Is it safe--or shall we say discreet?--to take us for a 'joy-ride' in one of the Sultan's air-craft?"

"If anything His Highness would be pleased to see me making a flight in gusty weather with two passengers; so say the word and I'll trot out the contraption. It's the only way."

"Carry on, then," assented Captain Restronguet.

Within the spacious outer courtyard of the palace stood a number of lofty sheds with sliding doors. At a wave and a gesture from the chief aviator a number of natives opened the doors and dragged a huge aero-hydroplane of an obsolete pattern into the sunlight. The machine was a biplane. Underneath the two long floats were four wheels, so that it could be adapted either for alighting and rising from the sea or land.

Jenkins critically examined various nuts and tension wires, started the engine, till the machine was all a-quiver with the vibration from the revolving cylinders.

"All correct," he bawled, for the rapid explosion of the motor practically deadened every other sound. "Get aboard."

Captain Restronguet occupied a seat immediately behind and slightly higher than the pilot, while Hythe sat behind the biplane. Jenkins vaulted agilely into his place, motioned to the attendants to stand clear and thrust home the clutch of the propeller shaft.

The aero-hydro-craft leapt over the ground for about twenty yards with a jerk that nearly capsized the two passengers; then soaring upwards it cleared the courtyard wall by barely six feet, passed over the upturned faces of a crowd of natives in the roadway, and shot rapidly across the harbour.

The motion was exhilarating, but the air, by contrast with the heat ashore, was cold and cutting to the faces of the passengers. Hythe realized that aeroplaning in white ducks, even in the Tropics, was rather out of place.

"Look, sir," he exclaimed. "There's the 'Topaze' going out."

"That's rotten luck," replied Captain Restronguet leaning sideways to watch the cruiser, that, a thousand feet below, looked no larger than a model boat. "Your friend Dewerstone has given the show away."

"I think not," replied the sub confidently. "He told me he was on leave till the day after to-morrow."

"Where's your ship, Tretheway?" shouted Jenkins.

"Away beyond Bawi Island. There she is."

"Rum looking craft, anyway," commented the aviator. "Looks more like a dog's kennel to me."

"Thanks," remarked Captain Restronguet in an undertone; then louder he added, "She's hove-to. If you come down within hailing distance they'll range up alongside to pick us up; they haven't a boat."

"Haven't a boat," ejaculated Jenkins. "Rum craft. Look here----"

He ended abruptly, for with a report like a pistol shot one of the wires supporting the wing plane snapped. The aero-hydroplane began to tilt ominously. Hythe and his companion instinctively realizing that a disaster was imminent grasped the rods nearest to hand in a grip of iron.

Pluckily the aviator strove by manipulating the elevating rudder to restore the doomed aircraft's equilibrium, but in vain. He, therefore, shut off the engine and attempted a vol-plane. Already the air-craft was standing almost on its nose, and falling with fearful velocity, till Captain Restronguet slid out of his seat and was prevented from falling clear only by his grasp upon a metal rod.

Finding that the machine was quite out of control, Jenkins touched a lever with his foot. Instantly a length of stout canvas trailed out astern. Before the aero-hydroplane had descended another fifteen feet the canvas, distended by the resistance of the air, took the shape of a huge parachute. The fall, though still rapid, was appreciably retarded, while the three men, literally hanging on tooth and nail, became aware that hope was not yet dead.

With a tremendous splash the wrecked aero-hydroplane struck the water. Hythe found himself torn from his support, and plunging feet below the waves. Fearing that he might be entangled in the sinking machine he struck out and swam a considerable distance ere he rose to the surface.

Shaking the water out of his eyes, he looked around. The aero-hydroplane was still floating, but with a heavy list. The concussion had burst the seams of one of her floats, which was now completely filled with water, while the other was leaking slightly. Clinging to the still buoyant float were the captain and Jenkins. The "Aphrodite" was nowhere to be seen.

"We're all right for the present," called out the former cheerily. "The water's warm and I have not seen any sharks about, and the cruiser will bear down and pick us up."

"Where's your ship, Tretheway?" asked the aviator anxiously. "We were falling close to where she was hove-to."

"I'm rather afraid she didn't spot us," replied Captain Restronguet. "And seeing the 'Topaze' approaching, she dived."

"Dived!" exclaimed the astounded Jenkins. "What d'ye mean? You don't mean to tell me the ship you belong to is a submarine?"

"It is," assented the Captain coolly.

"Not that rascally 'Vorwartz' by any chance?"

"No."

"Well, then, what's her name? I haven't heard of any other submarine in these waters."

"Not the 'Aphrodite'?"

"Don't try to be funny, Tretheway. You know as well as I do that that submarine was blown to atoms."

"I am afraid, my dear Jenkins, that I cannot agree with you. The 'Aphrodite' is even now submerged in the Zanzibar Channel, and I--whom you know as Hugh Tretheway--I am Captain John Restronguet."

CHAPTER XXV.

THE APPROACH OF THE "VORWARTZ."

Beyond muttering "Well, I'm dashed!" the aviator relapsed into silence. In vain Captain Restronguet and Hythe looked for a trace of the "Aphrodite." As a last resource the former produced a silk green and white flag from his pocket and lashed it to one of the vertical stays in the hope that the submarine might locate it by means of her periscope.

"They're carrying out orders," said Captain Restronguet at length. "I told Devoran to dive if he saw any vessel approaching. He spotted the 'Topaze' and immediately descended. It's awkward, because the secret is bound to leak out. But after all it is rather remarkable that it didn't become common property hours ago."

"How shall we get on board the 'Aphrodite,' sir?" asked the sub.

"We'll manage it sooner or later, but there's valuable time lost. Ha, there's the 'Topaze' altering helm. She's sighted us."

A quarter of an hour later the cruiser's gig picked up the three unlucky aviators, while the aero-hydroplane was secured and towed alongside before she sank, and was hoisted on board by means of a boat's davit. Dry clothing was immediately forthcoming, and clad in borrowed garments the rescued men were taken aft to be introduced and interviewed by the Hon. Charles Sedgwyke, captain of H.M.S. "Topaze."

Realizing that it would be useless to attempt to conceal anything Captain Restronguet made a full report of all that had occurred, and requested that he and his companions might be taken back to Zanzibar, whence the "Aphrodite" might be communicated with by wireless.

"I am afraid that it is at present impossible, Captain Restronguet," said the Hon. Sedgwyke. "We are under urgent orders to proceed to Delagoa Bay, for there that villainous von Harburg has been making himself particularly objectionable. We are to meet and co-operate with the 'Pique,' and should our efforts meet with success we are to carry on to Table Bay. There is, I am afraid, no option. You must accompany us, and no doubt, your valuable experience in connection with the affair will enable us to settle with the 'Vorwartz.'"

"I would much rather settle with her myself," replied Captain Restronguet.

"That I can quite understand. I can also safely assert that Captain Restronguet will not prevent the 'Topaze' from distinguishing herself by standing aloof when he might otherwise render us good service."

Captain Restronguet bowed. "Naturally," he added. "Our interests in the business lies in the same direction."

"Anything I can do to aid you I will most willingly do," continued Captain Sedgwyke. "I might suggest that the wireless of this vessel is at your disposal, and by sending a message to the Admiralty you could have it re-transmitted through your agent to the 'Aphrodite.'"

"An excellent arrangement," said Captain Restronguet, "only it is certain that the news will reach Karl von Harburg, and that is what I particularly wish to avoid."

"I trust that within the next few days Karl von Harburg will be totally indifferent to news of any description," remarked the captain of the "Topaze" drily. "But in the meanwhile make yourselves comfortable on board. You will, I hope, do us the honour of being a temporary member of the Ward Room. Mr. Hythe, who is still under the Naval Discipline Act, must, of course, mess in the Gun Room. I am still slightly hazy as to the exact official and social status of the aviator-in-chief to His Highness the Sultan of Zanzibar."

Three days later the "Topaze" was threshing her way southward at a good twenty-two knots and was approaching the rendezvous. It was now night, but the moon, shining with all the lustre that only the tropics can enjoy, made everything on deck quite discernible.

Surrounded by a group of officers, all of whom were most anxious to gather particulars of the rival submarines from two of the principal characters, Captain Restronguet and Hythe had to exercise their ingenuity to prevent themselves being "pumped," for even to their kind hosts it was not advisable to give themselves away. Nevertheless the time passed pleasantly. The paymaster's cigars were excellent, the surgeon was a lively raconteur, and the first lieutenant was kindness personified; but at length Captain Restronguet contrived to draw Hythe aside to the lee of the after nine-point-two-inch gun turret.

"No doubt you wondered why that fellow Jenkins addressed me as Hugh Tretheway," he began. "Well, it certainly was strange running across him in far-off Zanzibar. You may remember I told you that for some months, when down on my luck, I worked as an electrical fitter in Devonport Dockyard? That man Jenkins was in the same shop. He isn't a bad fellow by any means, though somewhat of a rough diamond. Hugh Tretheway is my baptismal name, but for certain reasons I preferred to drop it and assume the name of John Restronguet. I hope that for the present at all events you will keep that information a secret. I have already had a quiet talk with Jenkins on the matter, and from what I already know of him, he will be as silent as the dead."

"Of course I will carry out your wishes, sir," said the sub.

"Thank you. But to change the subject: what do you think of the chances of the 'Topaze' against the 'Vorwartz'?"

"She has her work cut out," replied the sub. "But I feel certain that every man on board will do his best."

"They cannot do more," added Captain Restronguet earnestly. "At the same time they are running needless risks when, once I locate the 'Vorwartz,' I could destroy her without a quarter of the danger. Suppose, now, that the Delagoa Bay report was false and Karl von Harburg is knocking about in these waters: what is there to prevent her from torpedoing the ship and sending her to the bottom?"

"That is a risk that every ship must run in naval warfare," replied Hythe. "Ever since the invention of torpedoes that risk has increased, and now that submarines form a formidable arm of the Naval Service there is still the greater possibilities of a ship being sent to the bottom without a shot in self-defence."

Before Captain Restronguet could say another word a hoarse order came from the fore bridge, followed by a shrill bugle-call for "General Quarters" and the long-drawn notes of the bo's'un's-mates' whistles.

"What's that?" demanded Captain Restronguet.

"'Clear for action'--a test order perhaps," replied Hythe. "See how those fellows get to work."

Up the companion-ladders officers hurriedly appeared, still fumbling with the buckles of their sword-belts. From for'ard tumbled a swarm of hefty bluejackets, who, invading the sacred precincts of the quarter-deck, began to unship stanchions, davits, ventilating-cowls, and other impedimenta; steel covers were lowered over skylights and companion-hatchways. The securing bolts of the after nine-point-two gun turrets were cast loose, and the long muzzle swung round, causing Captain Restronguet to hurriedly duck his head. In five minutes the quarter-deck of the "Topaze" was deserted, as were the other exposed parts of the ship, every man being at his station behind the armoured portions of the vessel.

Another bugle-call.

"As you were," exclaimed Hythe. "Suppose we go up on the after-bridge. They are exercising. Perhaps the next evolution will be 'Out collision mats.'"

"Hope they won't have to do it in real earnest," remarked his companion as the two men ascended to their coign of vantage.

Once more the bo's'un's-mates' whistles sounded while the bo's'un shouted in stentorian tones "Out nets." The cry was repeated in half a dozen different parts of the ship, and the hither-to deserted decks became a scene of disorder and chaos: at least that's what it seemed to Captain Restronguet, who was for the time being a stranger in a strange land.

Instinctively Hythe pulled out his watch, which once more had stedfastly resisted the assaults of the sea water. Captain Restronguet, gripping the rail, leant over and watched the scene of activity upon the moon-lit deck. Over the side of the gently-rolling craft active seamen slid down upon the apparently insecure net-shelves, and by a series of gymnastic feats succeeded in rolling ten tons of close-meshed steel netting over the side, to the accompaniment of shouts of "Look alive there!" from their officers. Hardly had the last man regained the deck ere the motor capstans of the fo'c'sle began to clank. Seamen armed with spars thrust at the ends of the torpedo booms to give the motor-worked wire rope a chance; then slowly yet surely the twenty hollow steel booms were swung outwards till the "Topaze" was encircled with a "crinoline" of nets at sufficient distance from the ship to stop a deadly torpedo. Back doubled the men to their stations for action.

The sub glanced at his watch. The evolution had taken only forty-five seconds.

"Smart work!" ejaculated Captain Restronguet.

"Yes," assented Hythe. "But we did it in forty seconds on the old flagship. Apparently Captain Sedgwyke is not satisfied for I can hear him storming to some one."

"It is hardly my place to offer suggestions," said Captain Restronguet, "but I think it would be advisable if they kept the nets in position. It might save the 'Topaze' from being torpedoed, although I know that the speed is greatly diminished by the drag in the water."

"We never do," replied the sub. "It is the first time I have seen 'Out nets' performed with the ship underway. It is essentially a defence when lying at anchor. There: 'In net defence,' they are going to stow the nets."

In the midst of the scramble that ensued the bugle suddenly sounded "General Quarters." To leave an evolution half completed was a very unusual thing.

Something prompted Hythe to look seaward. At less than a cable's distance the two conning-towers of a submarine had just appeared above the surface of the moon-lit sea, a smother of foam making them still more conspicuous. The sub gripped his companion's arm and pointed.

"The 'Vorwartz!'" he exclaimed.

Several of the officers of the "Topaze" had observed the sudden appearance of the sinister craft, and hence the call to General Quarters. The light quick-firers were manned, their muzzles swung round till they pointed full at the submarine's conning-towers, which, proceeding at nearly the same rate and in a similar direction to that of the cruiser, presented an easy target.

Captain Sedgwyke was puzzled. It was inexplicable that the submarine should show herself when she might have let loose a torpedo while completely submerged. Nevertheless he was on the point of giving the order to open fire when Captain Restronguet, in a voice that could be heard from one end of the ship to the other, shouted:--

"Don't fire, it is the 'Aphrodite.'"

Something in the captain of the "Aphrodite's" words prompted Captain Sedgwyke to issue a confirmatory order. Hythe was astonished--even doubtful. He could not be certain as to whether it was the "Aphrodite" or her counter-felt rival; but the inventor and constructor had made no error. It was the "Aphrodite."

Thirty feet in front of the fore conning-tower the sharp bows of the submarine appeared above the water, followed by the whole length of her decks, from which the water poured in silvery cascades.

Then a hatch was thrown open and a figure that Hythe recognized as that of the first officer appeared. Raising a megaphone Devoran shouted:--

"Is Captain Restronguet on board?"

"Ay, ay," replied a voice from the fore-bridge. "What submarine is that?"

"The 'Aphrodite,'," replied Devoran, merely as a matter of form, since his identity was now established. "Can you send a boat? We have important intelligence to communicate."

At that moment a petty officer ran up the ladder of the after-bridge and requested Captain Restronguet to speak to Captain Sedgwyke.

"I suppose you wish to board your craft," said the Captain of the cruiser. "We will lower a boat as soon as we get a bit shipshape."

"If you will kindly do so I will rejoin the 'Aphrodite,'" replied Captain Restronguet. "At the same time I think the information is urgent. Shall I ask my first officer to deliver it verbally to save time?"

"Very good," assented Captain Sedgwyke.

The information was indeed startling. The electric detector of the "Aphrodite" had picked up the position of the "Vorwartz." Karl von Harburg's submarine was proceeding northwards, and was even now within twenty miles of the British cruiser.

CHAPTER XXVI.

THE SINKING OF THE "TOPAZE."

"This is indeed news!" exclaimed Captain Sedgwyke. Then in a lower tone he added, "Captain Restronguet, will you do me a favour? If we fall in with the 'Vorwartz' will you stand off and give the 'Topaze' a chance to distinguish herself? If so you will earn the gratitude of every officer and man on board."

The captain of the "Aphrodite" hesitated a few moments.

"Captain Sedgwyke," he replied, "you have asked a hard thing. Had any other captain made me a similar request I would have declined. But I owe you a debt of gratitude for having picked us up out of the sea. I will do as you request. I will give you an hour's uninterrupted action from the time the 'Vorwartz' is within four miles of us. One thing I would suggest, the 'Vorwartz' is the attacking vessel; you will not have to pursue her, so, since speed is not a vital consideration, keep your torpedo nets out."

"I, too, am indebted to you," said Captain Sedgwyke. "In an hour I hope to be able to help to uphold the glorious traditions of the Flag under which I serve."

"You have my best wishes," added Captain Restronguet as he turned to go over the side into the waiting boat. "At the end of the hour it will be my show; but should you require any assistance before then either communicate by means of wireless--I will order the coil to be adjusted as soon as I get on board--or else give four blasts in quick succession should anything happen to put the wireless out of gear."

"Are you taking Mr. Hythe?"

"Certainly; he is officially lent to the 'Aphrodite'; and Mr. Jenkins will accompany us, since I am morally responsible to His Highness, the Sultan of Zanzibar, for his safety."

The two captains shook hands, and Captain Restronguet and the sub entered the waiting boat, which had to pass over the upper edge of the torpedo nets that had to be lowered beneath the surface for the purpose.

Barely was the cruiser's boat clear of the "Topaze" when the order came "Out nets."

"Captain Sedgwyke is acting upon my suggestion," observed Hythe's companion. "It is the best plan, but honestly I favour the chances of the 'Vorwartz.'"

"You have a bias towards the advantage of submarines," said Hythe. "At the same time you must remember Karl von Harburg has, for the first time, to try conclusions with a British ship whose guns are sighted by trained seamen-gunners."

"We shall see," observed Captain Restronguet oracularly, and both men relapsed into silence until the boat ranged alongside the "Aphrodite."

"'Vorwartz' is now only eleven miles off, sir," announced Devoran. "We've cleared for action, I presume you will go straight for her, sir?"

"No," replied Captain Restronguet. "We are going to run away."

"Run away, sir?"

"Yes; in a moment of weakness I promised the captain of yonder cruiser to give him a free hand for one hour from the time the 'Vorwartz' gets within four miles of her. He wishes to distinguish himself. Accordingly we will run northward and put a good two miles between us. That, I think will be a safe distance, for on no account must we let the 'Vorwartz' spot us, or she will be off like a startled hare."

Hythe took up his position in the wake of the foremost conning-tower, whence he could command an uninterrupted view of the "Topaze." The British cruiser made a fine picture in the dazzling moonlight in spite of her ugly lines and the absence of masts and funnels. Already her boat had returned, but, instead of being hoisted to the davits, was made fast astern, while the remaining boats were being hurriedly yet methodically lowered into the water, one man being placed in each to act as boat-keeper. These were taken in tow of a motor-cutter, so that they would be safe from any explosions against the side of the ship.

This done, the "Topaze" trimmed her fringe of nets, and forging slowly ahead, bore down in the supposed direction of the on-coming "Vorwartz."

There was no attempt at concealment. Her so-called masthead light, hoisted on the slender signalling-mast abaft the conning-tower, was burning brightly; Hythe could see the green starboard lamp throwing its reflection upon the scintillating water. It was part of Captain Sedgwyke's plan to deceive the "Vorwartz." The latter, thinking she had fallen in with a large tramp, would doubtless either fire a torpedo at her to wantonly send her to the bottom, or else rise to the surface and demand her to surrender. In the first case the torpedo would, he hoped, explode harmlessly against the net. The submarine would then rise to enable the scoundrel Karl von Harburg to witness the sinking of his latest victim. In the event of either of these possibilities taking place the "Vorwartz," once on the surface, would be the target for twenty powerful quick-firing guns, and since the "Topaze" nearly headed the list of results in the Gunlayers' Test for the whole of the British Navy, the destruction of the modern pirate seemed certain.

Captain Sedgwyke was a man who scorned to take a mean advantage; and since he would not encroach upon the distance limit set down by his chivalrous rival, he ordered the helm to be put over, thus keeping the "Topaze" within a radius of three cables' length, until the "Vorwartz" was within four miles of him. Seeing this Captain Restronguet gave the word for half speed ahead, until he placed a distance of two miles between him and the cruiser.

"Seven and a half miles, sir," announced Devoran.

"Then another two minutes will be the commencement of the hour's limit," said Captain Restronguet consulting his watch. "Mr. Kenwyn, will you please signal the 'Topaze' and give her the latest information as to her enemy's position." The second officer, adroitly working the flashing lamp, communicated the intelligence, receiving in reply an affirmative signal.

Practically every officer and man, except those on urgent duty below, stood on the upper platform of the "Aphrodite." Telescopes and binoculars were brought to bear upon the cruiser that now looked like a phantom castle in the moonlight.

Hythe felt his blood tingle in his veins. He realized that he was to be the spectator of a duel to the death between a cruiser and a submarine--the first engagement of such a character that had ever taken place in naval history.

"Four miles, sir," announced Devoran, as the position of the "Vorwartz" was reported to him by the seaman stationed at the detector. "She's coming straight for the cruiser, by Jove!"

"I thought she would swallow the bait," exclaimed Hythe.

"Let us hope she will swallow more than is good for her," added Kenwyn. "By Jove! The 'Topaze' has opened fire."

A flash like distant lightning seemed to leap from the cruiser's deck, followed by another, and then by a regular salvo of quick-firers. Ere the first deep report reached the ears of the watchers on the "Aphrodite" the "Topaze" unscreened her search-lights and played them on a spot about four hundred yards on the starboard hand, where the shells were churning up a perfect cauldron of foam and spray.

"Good heavens! they've hit something!" exclaimed several voices. Those of the "Aphrodite's" crew who possessed glasses could see a dark mass, rent in deep furrows by the projectiles, appear amid the columns of foam; then throwing itself ten feet into the air the object disappeared from view.

Captain Restronguet clenched his fists. He deeply regretted his action in allowing the captain of the "Topaze" a free hand. His quest was over. The rival submarine had been sent to the bottom with all hands, and he----

"Cruiser signalling, sir," announced Kenwyn, who was perched upon the rounded top of the fore-conning-tower. "Reports having wasted ninety rounds of ammunition by firing at a whale, and requests to know whether the captain of the 'Aphrodite' has been guilty of a senseless joke?"

"Senseless joke, indeed!" ejaculated Captain Restronguet. "If those fellows in their excitement mistake a whale for a submarine they will be rudely awakened when the 'Vorwartz' does show. Senseless joke, indeed! Look here, Mr. Kenwyn, reply that my detector does not record the presence of whales, but it does record the presence of the 'Vorwartz.' She is now only--how many miles, Mr. Devoran?"

"Two and three quarters from us, sir."

"Only three quarters of a mile from the 'Topaze,'" continued the Captain. "It was quite possible that that wilful waste of ammunition made the valiant Karl von Harburg turn tail; but evidently such is not the case. It has made the task of the 'Topaze' still more difficult, since the 'Vorwartz' is now aware that she is not about to tackle a merchant vessel."

The "Topaze" had now shut off her searchlights, and was slowly circling to port. After the deafening cannonade there seemed an ominous silence in the air. The detector showed that the "Vorwartz" was still approaching.

"She will be within range shortly," remarked the sub. "I hope to goodness those nets will ward off the torpedoes. What charge do they carry, sir?"

"I believe I am right in saying a charge of eighty pounds of nitro-gelenite, which is equivalent to nearly a ton of gunpowder. You may remember how the shock of the explosion shook the 'Aphrodite' in the chase off Ushant?"

"Rather," remarked Hythe. "At that time I----"

A column of mingled flame and water bursting apparently from the fo'c'sle of the "Topaze" effectually checked the sub's remarks. To the watchers on the "Aphrodite" it seemed as if the bows of the cruiser were lifted clear of the water. Then came a deafening detonation, like the noise of thunder above one's head.

The cruiser rocked violently two or three times, then seemed to settle on an even keel, while her quick-firers blazed away in a frantic, aimless manner, for several of the projectiles could be observed striking the water a mile apart.

"Any wireless message?" asked Captain Restronguet coolly.

"No, sir," replied Kenwyn.

"She's withstood the shock, thank heavens!" ejaculated Hythe, then, "No, she hasn't, by George! There's 'Out Collision Mats,'" he added, as a bugle rang out from the stricken ship.

"'Vorwartz' is making off, sir," announced Mylor, who had relieved the observer at the electric detector.

"Hard lines on us," exclaimed Captain Restronguet. "What are we to do? The hour is not anything like up, and no signal of distress from the 'Topaze.' Send them a message, Kenwyn. Wireless, please."

"No reply, sir," announced the second officer after a wait of nearly two minutes.

"Then her wireless is disabled by the shock. Speak her in Morse, Kenwyn. Ask whether Captain Sedgwyke will release us from the remainder of our period of inaction, as the 'Vorwartz' is now making off in a southerly direction."

But before Kenwyn could get to the flashing signal lamp four loud blasts from the motor fog-horn of the "Topaze" sent forth their cry for urgent assistance.

"She's settling down by the bows," exclaimed one of the spectators of the ocean drama.

"Full speed ahead," ordered Captain Restronguet. Within five minutes from the request for aid the "Aphrodite" was abreast the stricken vessel at less than a cable's length away. Her fore part, already deep in the water, showed unmistakable signs of the mortal blow she had received. Her armoured belt, that extended right to the bows, had already disappeared from view, but for nearly thirty feet on the starboard side and nearly opposite the for'ard nine-point-two-inch gun the lighter steel plates were rent and buckled in all directions. Over the gaping wound a collision mat had been placed, but one might as well attempt to stop a mill-stream with a mop-head.

The order had already been given to abandon ship, and with the utmost precision and coolness the seamen were drawn up to await the approach of the cruiser's boats, that were now only a few yards off.

"Do you want me to pick up any of your crew, sir? I'll stand by if you desire it," shouted Captain Restronguet to a solitary figure on the steeply-inclined fore-bridge that the men of the "Aphrodite" recognized as Captain Sedgwyke.

"Thank you," replied the captain of the "Topaze." "We have enough room in the boats for the whole of the ship's company. Do you, sir, kindly take up the work that I had the misfortune to interrupt you in, and may you have better luck."

Captain Restronguet gravely saluted the gallant yet ill-fated officer. At the same time, although anxious to set off in pursuit, he was loth to leave the cruiser until every man was saved.

"What are you waiting for, sir?" hailed Captain Sedgwyke, his voice barely audible above the hundred different noises emanating from the doomed cruiser, as the water, pouring in, broke down bulkheads, swept buoyant objects 'tween decks in a wild stampede against the partitions, and caused the imprisoned air to escape with a vicious hiss.

"I am standing by," replied Captain Restronguet. "You gave a signal for urgent aid, sir."

"We thought the ship would sink before the boats could arrive," said the captain of the "Topaze." "There is no danger to life. Our consort the 'Pique' is on her way to pick us up."

Still Captain Restronguet stood by. He was not so sure that the "Pique" might not share the same fate as the "Topaze" since the "Vorwartz," going south, was almost bound to fall in with the British cruiser from Delagoa Bay.

Just then the "Topaze" gave a sudden lurch to starboard, heeling so much that the line of men still remaining on board was broken. But only for an instant, it was the unexpected lurch and not panic that caused the seamen to move out of position. Sharply they redressed line--and waited.

Boat after boat received its full complement, and pushed off to a safe distance lest the cruiser in her final plunge should swamp them. Not until the last of his officers and men had taken to the boats did the gallant captain descend from the bridge.

It was touch and go with him, for to gain the boat he had to wade up to his waist in water that swirled over the steeply sloping decks.

"She's going!" ejaculated Devoran.

Heeling more and more the "Topaze" turned completely on end, so that the whole length of her keel plates and her four propellers were out of water. Then, slipping bows foremost, she disappeared from view in a smother of foam, leaving only an expanse of oil and petrol, a few floating pieces of timber and her boats to mark the grave of a splendid cruiser. Twenty seconds after she had disappeared the muffled sound of an explosion--the bursting of the air in one of her compartments--threw up a column of water that almost swamped the nearest boat, the gig in which Captain Sedgwyke had taken refuge. That was the last message from the "Topaze" as she sped to her ocean grave one hundred and eighty fathoms beneath the surface.

CHAPTER XXVII.

A PILOT UNDER COMPULSION.

Dawn was just breaking as the "Pique" arrived on the scene of the disaster. Her escape, of which her crew were totally in ignorance, was owing solely to the fact that Karl von Harburg had fired his last torpedo at the ill-fated "Topaze." His means of offence were now reduced, for the power of being able to deliver his antagonist a smashing blow below the surface was no longer possible: he could only ram. Yet the captain of the "Vorwartz" hesitated to attempt to deal thus with the "Pique." The British cruiser had passed within two cables' length of where the modern buccaneer was running beneath the surface; but the risks to himself by ramming a large armoured vessel travelling at thirty knots were far too great.

Seeing that he could render no further assistance Captain Restronguet ordered the "Aphrodite" to be submerged. It was the safest plan, for although he communicated with the "Pique" by wireless, the message was not in code, and the British cruiser, determined to take no risks, might open fire at the submarine.

The position of the "Vorwartz" was now, according to the detector, forty miles S.W. of her pursuer. When Captain Restronguet came to fix her position on the chart he knitted his brows in perplexity. The rival submarine was, if his information was correct, actually within the delta of the great Zambezi River.

"Now we have her!" exclaimed Captain Restronguet gleefully. "It will be a bit of a shock to Von Harburg when he finds that his return journey is barred by the only craft he feared and one that he thought he had destroyed."

"Do you think he's heard that the 'Aphrodite' was not smashed up after all?" asked Hythe.

"It is doubtful. If he has I can only conjecture that he has decided to ascend the Zambezi in the hope of eluding us. Otherwise I cannot suggest any reason unless he wishes to form a base in this unhealthy Portuguese territory since his Sumatran refuge is closed to him."

"I have heard that the district is reeking with fever, sir," remarked the sub. "Many times men-of-war have sent exploring parties up the river and almost invariably some, and once every man, of the crew have been stricken down. The Portuguese have, apparently, taken no active steps to rid the locality of the mosquitoes. If the deadly climate could be rendered habitable, as in the case of the Canal Zone at Panama, the Zambezi would be one of the greatest trading arteries of the world."

"Some day it will," said Captain Restronguet. "The British Government has had its eye upon Portuguese East Africa for some time. Could the Portuguese Republic be induced to sell it there would be a splendid outlet for Rhodesia, and under active management the Zambezi would make a splendid waterway. Even now it is navigable as far as Kebrabassa Falls, nearly three hundred miles from the delta."

"It strikes me, sir, that we shall be grilling in a fetid atmosphere before many hours are past," observed Devoran. "Why couldn't Karl von Harburg stick to the sea?"

"There's nothing like variety," replied Captain Restronguet complacently. "After we've settled with the 'Vorwartz' we may have a little shooting; lions and rhinos are fairly plentiful, to say nothing of smaller fry. But I do not think we need entertain fears of the climate. It is only at night that the pestilential mists are really dangerous. Every day just before sunset, we will submerge the 'Aphrodite,' since there is reason to suppose there are deep holes in the bed of the river for this to be done even if the normal depth is insufficient. We shall not thus be inhaling the noxious gases, nor be exposed to the attacks of mosquitoes and other germ-bearing insects; whilst river-water passed through our condensers will be perfectly drinkable."

According to the rosy views held by the captain of the "Aphrodite" the new phase of the cruise was to be a sort of picnic; but he had reckoned without his host.

On arriving off the First Bluff Point, on the western side of the main outlet of the Zambezi, it was found that there was such a heavy tumble on the bar that to attempt to cross it would be an impossible task.

The detector showed that the "Vorwartz" was maintaining her distance; evidently she was in luck, and had negotiated the difficult entrance in the nick of time.

For twenty-eight days the "Aphrodite" lay in sight of the clump of high, straight trees, that lay very close together, giving the point the appearance of a cliff, to which the name of First Bluff Point owes its origin.

Meanwhile the news of the great disaster to H.M.S. "Topaze" had been sent by wireless to Cape Town by the captain of the "Pique," and in a very short space of time the Admiralty were in possession of the salient facts of the latest outrage by Karl von Harburg. There was a panic amongst the merchantmen in East African waters; the scanty harbours of that coast were filled with ships whose skippers feared to put to sea. Even the mail-boats took particular care to give the supposed cruising-ground of the "Vorwartz" a wide berth; while the liners running between London and Liverpool and Australia and New Zealand abandoned the Cape route and stuck to that via Cape Horn.

People began to ask what was the use of having command of the sea when one solitary submarine could do practically what it liked beneath the surface. Vast sums had been spent to keep the British navy in a state of efficiency and numerical supremacy; money had been poured out like water to provide defence against hostile aircraft that might menace our shores; yet one submarine--not a new invention, but merely a great improvement on existing types--was playing a one-sided game not only with British shipping, but with the mercantile marine of the whole of the nautical world. And now even warships were being sent to the bottom without so much as a glimpse of the attacker.

In the midst of this gloomy outlook came a consoling gleam of light. The "Aphrodite" was now known to have survived the attack made upon her by her rival; and to Captain Restronguet the entire civilized world pinned its faith.

Although Captain the Hon. C. L. Sedgwyke had refused to make any public statement concerning the disaster to his ship until the impending court martial took place, he telegraphed a full report to the Admiralty. It was the plain, unvarnished story of a brave yet unfortunate British officer. He laid particular emphasis upon the fact that Captain Restronguet was in the "Aphrodite," ready and willing to grapple with the modern buccaneer, but only at earnest solicitation of the captain of the "Topaze" did he stand passively aloof in order to give the British cruiser a chance to distinguish herself.

Britons are generally supposed to be a phlegmatic race, but when they have an attack of hero-worship they get it pretty badly. Captain John Restronguet was the hero of the day. A photograph that an amateur photographer on the "Persia" took of him during the "Aphrodite's" passage through the Red Sea appeared in all the papers, edition de luxe copies were sold by hundreds of thousands, and the firm who bought the copyright for one guinea made nearly £30,000 out of the transaction. Restronguet coats, hats, and boots were all the rage; in fact the name Restronguet applied to any article ensured it a ready sale. The nation was Restronguet mad.

But the captain of the "Aphrodite" was not a man to have his head turned by fatuous hero-worship. He knew perfectly well that in the course of a few years his name would be a mere byword. Reports of his popularity had been transmitted to him by his agents. He merely shrugged his shoulders, and impressed upon the wireless operator who received the messages to maintain a strict reticence as to their nature. He had a mission to perform, and he meant to accomplish it. Thus, with ill-concealed impatience he waited and waited till, with his crew, he became heartily sick of the sight of First Bluff Point and the forbidding bar of the mighty Zambezi.

On the morning of the twenty-ninth day of the "Aphrodite's" detention a native boat, manned by half a dozen blacks, was observed to have managed to cross the bar and was bearing down towards the vessel. In the stern was a European, a sallow-faced man dressed in dirty white clothes and a broad sun-hat.

As soon as the boat came alongside the bowman dexterously threw a rope, and when this was made fast the white man, without waiting for an accommodation ladder to be shipped, swarmed up on deck.

"Me pilot," he explained, with a deep bow and a flourish of his hat. "Me pilot 'pointed by Republic. Me take you in."

"Is it safe to cross the bar?" asked Captain Restronguet eagerly.

"Yes, senhor; me take you in for so many milreis," and he held up the fingers of both hands four times.

It was a matter of nearly nine pounds--thrice the amount the Portuguese expected to receive. It was part of his nature to make allowances for being beaten down.

"I'll make it gold to the value of eighty milreis if you put me inside the bar to-night," said Captain Restronguet.

"Me take you up to Marromea--that am de port--for dat," exclaimed the pilot gleefully. "How much you draw?"

"Twelve feet," replied Captain Restronguet.

The Portuguese had no need to make a calculation to arrive at the depth in "bracas," since the British fathom is almost identical with the Portuguese "braca."

"Too ver' much," he exclaimed, shaking his head.

"I can reduce it to seven feet."

"How can do? You no throw cargo oberboard?" asked the astonished Portuguese.

Without replying, Captain Restronguet gave an order for the emergency tanks to be emptied, and still greater was the pilot's amazement to find the vessel rising higher and higher out of the water.

Suddenly it occurred to his slow-witted brain that the craft he had boarded was a submarine, and since the only submarine he had heard of was the "Vorwartz," that had made the passage under cover of night, he came to the startling conclusion that he had boarded the pirate vessel. His olivine features turned a sickly yellow till there was hardly any contrast between his face and the whites of his eyes, and turning, he made a rush for the side.

"Steady, my worthy friend!" exclaimed Captain Restronguet, as Devoran and Kenwyn caught the Portuguese by the shoulders. "A contract is a contract. You've got to pilot my vessel over the bar."

"Mercy, senhor!" whined the fellow falling on his knees.

"Get up, you idiot!" said Captain Restronguet sharply, but all to no purpose; the pilot maintained his entreaties at the top of his voice.

"I believe he imagines he's on board the 'Vorwartz'," suggested Hythe.

"Perhaps," agreed the captain, then addressing the pilot he told him that he was in no danger, and that he was on the "Aphrodite."

But the man was so terrified that the words fell on deaf ears. His terror was increased by a sudden commotion over the side as his native crew, hearing the cries of their master, took their paddles and made off for the shore as hard as they could urge their cumbersome craft.

At last Captain Restronguet became out of patience with the craven pilot. At a sign from him Devoran whisked the Portuguese to his feet and led him for'ard. Here he again collapsed, grovelling on the deck. It was now nearly high water, and unless something were done another delay of twelve hours at least--possibly of days--would necessarily ensue.

Drawing his automatic pistol he clapped the muzzle to the pilot's temple. The touch of cold steel did what words had failed to do. Abject terror was banished by the stern menace of that small yet powerful weapon.

"No shoot, senhor capitan!" howled the wretched man. "Me take you ober: no shoot."

Captain Restronguet replaced his pistol, the pilot, still shaking, stood in front of the helmsman in the fore-conning-tower and directed him by movements of his hand. Four minutes sufficed to bring the "Aphrodite," rolling like a barrel, through the agitated water on the bar, and thus after nearly a month of inaction the avenging submarine floated in the turgid waters of the broad Zambezi.

CHAPTER XXVIII.

IN THE BALLAST TANK.

At Marromea Captain Restronguet paid the pilot, who was taken ashore in a native boat. The Portuguese, as soon as he received his money and found that he had not been harmed, became quite enthusiastic over the generous "Ingles," and vowed that, whatever other work he had in hand, he would await the "Aphrodite" on her return. "If the senhors ever come back," he added darkly, for he knew the effect of the pestilential climate upon unseasoned Europeans.

Marromea, where the Portuguese once had a fairly prosperous trading station, had fallen into decay. Fever had decimated the inhabitants, the railway, intended to fellow the course of the river and effect a junction with the Cape to Cairo line at Victoria Falls, had been abandoned. Long grass and tropical foliage had already hidden the melancholy remains from view.

There were scarcely thirty Portuguese in the place; the others were natives who, being partly civilized, were infinitely greater scoundrels than their unenlightened brethren. Of the thirty Portuguese, two-thirds of the number were Government officials, and with the idea of displaying their powers, threw every obstacle in Captain Restronguet's way. Dues were demanded and paid, then a peremptory request to be shown the ship's papers--documents that the "Aphrodite" did not possess.

Fortunately Hythe had a sheet of printed matter that he had brought off at Gibraltar with his purchases, and this was duly presented. After a lengthy scrutiny the officials returned it, saying the papers were quite in order but forty milreis must be paid to visé them.

"I'll see you to Jericho, first!" exclaimed Captain Restronguet wrathfully, and ordering his men to arm themselves he paraded them on deck as a gentle hint to the mercenary representatives of the Portuguese Republic.

If they knew of the presence of the "Vorwartz" in the river the authorities would not admit it; they refused to allow the telegraph to be made use of to communicate with the trading stations up-stream, and resolutely declined to provide a pilot for the navigation of the shoal-encumbered reaches as far as Kaira--a hundred miles above Marromea.

At last Captain Restronguet resolved to take stern measures. He was ready to abide by the usual customs of a foreign country, but he was not going to be fooled by a pack of rascally Portuguese.

"Clear for diving, Mr. Devoran!" he shouted.

The Portuguese officials, filled with curiosity, lined the edge of the wharf, talking volubly amongst themselves, while to show their contempt towards the foreign craft they amused themselves by throwing cigarette ends upon her deserted deck.

Down below the crew tumbled; hatches were secured, and the ballast tanks flooded. The "Aphrodite," made fast bow and stern to the wharf by the hempen hawsers, sank till her deck was only a few inches above the water. It was now just after high water, and there was a depth of forty feet alongside the quay.

Then with a jerk the strain on the ropes began to tell, a large portion of the crumbling quay was destroyed and tumbled into the river. Down sank the submarine till the tops of her conning-towers were fifteen feet beneath the surface. She was resting on the bottom of the river.

"Man the aerial torpedo tube, Mr. Kenwyn," ordered the captain. "Give them a sixteen pounds charge."

With a whizz and a roar the projectile leapt through the water and soared four hundred feet in the air. There it burst, the concussion shaking every miserable hovel in Marromea to its foundations. When the "Aphrodite" returned to the surface the quay was deserted; the terrified officials, suffering with injured ear-drums, were skulking in the bush.

"WITH A WHIZZ AND A ROAR THE PROJECTILE LEAPT THROUGH THE WATER."
"WITH A WHIZZ AND A ROAR THE PROJECTILE LEAPT THROUGH THE WATER."

"Ah, that is what we want," remarked Captain Restronguet, pointing to a ship's whaler lying on the quay. "Under the circumstances, considering how extortionately we have been charged, I have no qualms in annexing yon craft."

The whaler was a heavy one, but a dozen men soon brought her on board. This done the "Aphrodite" cautiously made her way upstream, for mudbanks and shoals abounded, and only by the frequent use of the lead was the submarine, running light, able to keep to the main channel.

It was now within two hours of sunset, and the "Aphrodite" had to find a suitable berth in order to carry out the plans Captain Restronguet had suggested for the safeguarding of his crew.

The confiscated boat had been securely lashed down amidships. It was too large to be taken below through the hatchway, but in order that it would not burst its lashings as the submarine sank Mylor bored four fairly large holes in the garboards so that the water could easily make its way out. The holes could be plugged when the whaler was required for service afloat, and as Hythe remarked an additional washing would do a lot of good to a boat that had been left lying on the wharf of that malodorous and inhospitable town.

Fortunately a fairly deep and extensive hole was discovered in the bed of the river, the soundings giving ten fathoms. Being the rainy season the river was three or four feet higher than its normal level, a circumstance greatly in the favour of the submarine's voyage of exploration and retribution.

The night passed fairly quietly, the air within the submarine being perfectly clear. Looking through the observation scuttle the crew could see that the so-called fresh water was of a deep brown colour, while the full moon, shining through the miasmic mists looked like a ball of greenish yellow copper. Occasionally a crocodile would alight upon the deck of the "Aphrodite" and drag its armoured body over the metal plating with a dull metallic sound. Once a couple of hippopotami in their moonlight gambols brushed against the side of the conning-tower, the shock being distinctly felt by the men on watch.

In the morning the detector registered the position of the "Vorwartz" at eighty-five miles, which was precisely the same distance as it gave overnight.

Not until the mists had disappeared did Captain Restronguet order the "Aphrodite" to be brought to the surface and the hatchways opened. He would not risk the health of his crew by exposing them to the fever-laden atmosphere. Almost as far as the eye could reach the water extended, for being in flood the river, wide under ordinary circumstances, now resembled a vast lake.

Proceeding at twelve knots, that took her over the ground against the current at barely nine miles an hour, the submarine held steadily on her course, literally feeling her way between the shoals of loathsome black mud.

Just before noon a motor-launch manned by Portuguese passed, downward bound. In reply to a signal to close, the little craft ran alongside the "Aphrodite" without the faintest hesitation. Two of her crew who could speak French were interrogated by Hythe. They had neither seen nor heard anything of a vessel resembling the "Vorwartz" although they had come from Tete, a few miles below the limit for navigation. In reply to a request that one of their number should accompany the submarine as far as Sena, to act as a pilot, the Portuguese resolutely refused, saying that a qualified man could be obtained at Molonho, ten miles further up the river.

"What does the detector say, Mr. Kenwyn?" asked Captain Restronguet for the tenth time that morning.

"Eighty-three miles, sir."

"H'm; two gained. But it's very strange that that motor-boat should not have noticed the 'Vorwartz.' Perhaps the river is deeper, and Karl von Harburg took the precaution to run submerged."

"It is wide enough for a large craft to pass unnoticed," said Devoran.

"Not the actual channel; if we went half a mile to port or starboard we would be hard and fast aground."

"Is it likely that the 'Vorwartz' has taken to a backwater?" asked Hythe.

"By Jove! I hope not," exclaimed Captain Restronguet; then in a confident tone he added, "No matter, our detector will locate her. One thing we know, she hasn't ascended the Shiré--a tributary that drains Lake Nyassa. I almost wish she had, for I would like to see the final act take place in British waters."

To guard against the tropical heat awnings had been spread fore and aft, extending the whole length and breadth of the deck. Under this the officers and crew not on duty "stood easy," the former seated in deck-chairs brought from the cabins.

To Hythe the voyage seemed more like a pleasure trip than a mission of destruction. He and Kenwyn amused themselves by shooting at crocodiles and hippopotami that frequently came within a hundred yards of the "Aphrodite," while Captain Restronguet did a more practical act by bringing down a bird resembling a turkey, which, falling on the awning, was received as a welcome change to the menu.

Captain Restronguet was in high spirits, but his enthusiasm received a set-back when the "Aphrodite" ran full tilt upon a shoal. It was through no fault of the leadsman. The depth gave six fathoms but a few moments before. The discolouration of the water prevented any indication of the shoaling of the depth from being noticed. It was simply a case of sheer bad luck.

"Empty the reserve tanks," ordered Captain Restronguet, for the "Aphrodite" was now drawing ten feet for'ard and twelve aft. Quickly the foremost tank was emptied, but the after one, in spite of the action of the powerful pumps, refused to be discharged. Consequently the draught for'ard decreased while the submarine's stern sank lower into the slimy mud.

"Full speed astern," was the next order, but beyond churning up the brownish black ooze the propellers failed to do the slightest good.

"Lay out an anchor, Mr. Devoran," exclaimed his superior officer. "Be sharp, for the tide is falling."

Hastily the boat was lowered, the heaviest anchor slung underneath, and laid out a hundred yards astern. The stout hempen hawser was led to the motor capstan, but as the powerful machinery made it revolve it simply "walked home" with the anchor. The soft mud offered little or no resistance to its broad palm.

The "Aphrodite" seemed doomed to remain hard and fast for another ten hours. Night with all its terrors would envelop her ere the next tide was at its height, and to work in the germ-laden mists was to court the deadly fever.

"Can the ballast tank be got at from the inside, sir?" asked Hythe, struck by an inspiration.

"Not without flooding one of the sub-divisions of Number Three Platform," replied Captain Restronguet. "But why do you ask?"

"I thought perhaps I might put on a diving-dress, and enter the tank and examine the valves."

"It's feasible," observed Captain Restronguet. "If you attempt it and succeed I shall be still more indebted to you."

"Then I have your permission?"

"Certainly."

"Look here, Hythe," exclaimed Kenwyn. "If you tackle the job I'm with you."

"Thanks," replied the sub. "The sooner we start the better."

Donning their diving-suits and equipping themselves with brushes, spanners, rubber-sheeting for the valves, and an electric lamp each, the two men entered No. 4a compartment, as the subdivision was designated. As soon as the water-tight doors were shut they began unbolting the man-hole cover that gave access to the faulty ballast-tank, guided in their self-imposed task solely by the rays of the lamps.

Presently the water began to ooze between the partially removed cover and side of the tank, increasing in volume till the whole of the compartment was flooded with a liquid resembling thick pea-soup. It was only by the concentrated rays of the two lamps and by keeping his helmeted head within six inches of the metal lid that Hythe was able to complete the work of opening a means of communication with the ballast-tank.

As soon as this was done the sub squeezed through the manhole. His feet touched a thick layer of stiff mud on the floor of the tank. Bringing his lamp down he carefully examined the outlet valve. The secret of the defect was his: when the "Aphrodite" had been submerged by the side of the wharf at Marromea the inrush of water had brought with it a quantity of sediment sufficiently plastic to form a layer over the outlet valve and thus prevent its action.

For an hour Hythe toiled. He had neglected to bring anything of the nature of a spade, and had to recourse to his bare hands. Handful after handful of the noxious mud he scooped up and passed through the manhole into the compartment without, till the interior of the tank was perfectly free from anything of the nature to retard the action of the pumps.

After a lapse of two hours and a half from the time of entering the compartment the two men, their diving-dresses covered in slime, gave the pre-arranged signal to start the pumps. Ten minutes later both the compartment and the tank were emptied of water, and the task of replacing the cover was proceeded with.

But even then Hythe, nothing if not practical, refused to come on deck. He asked for a couple of buckets full of strong disinfectant fluid to be sent down, and, using a mop vigorously, he thoroughly scrubbed out the interior of the compartment, finishing up by mopping his companion's dress with the liquid, while Kenwyn performed the same office for him. Thus the risk of fever from the river-mud was entirely obviated.

"I would like a cold bath," exclaimed Kenwyn as the two officers rejoined their comrades.

"You jolly well won't, then," replied Hythe emphatically. "At least unless you wish to pay an indefinite visit to Davy Jones. Why, man, you are as warm as you can possibly be. Have a hot bath, if you like. I will, with plenty of disinfectant in it."

By this time the "Aphrodite," her draught aft considerately lessened, was afloat and resuming her voyage. Kenwyn had had his hot bath and foolishly sat in the fairly strong breeze to cool himself afterwards.

Before night he was lying unconscious in his bunk, prostrate with blackwater fever.

CHAPTER XXIX.

THE "PRIDE OF RHODESIA."

Kenwyn's serious illness was a source of anxiety and perplexity to his chief. Captain Restronguet was loath to leave him ashore in an unhealthy district where medical comforts were of a most primitive nature, while to keep the patient on board was undoubtedly detrimental to the health of the rest of the crew and consequently a stumbling-block to the success of the expedition.

Finally he compromised the difficulty. Kenwyn was to be isolated from the rest of the crew, Mylor and Lancarrow volunteering to act as nurses, until the "Aphrodite" entered the gorge through which the Zambezi flows. Here the patient was to be landed, placed in a tent and left in charge of the two men till the "Aphrodite's" return.

Just below the town of Kaira, where the Shiré River joins the Zambezi, definite news came to hand concerning the "Vorwartz." A large canoe, laden with millet, arrived the same day as the "Aphrodite." Her crew reported, through a Portuguese interpreter who spoke indifferent English, that they had passed a strange-looking vessel, somewhat resembling the "Aphrodite," four days up the river, and that it was hard aground at the mouth of a tributary known as the Zampa.

This report was confirmed by the detector which gave the "Vorwartz's" position as sixty-three miles to the north-west. Captain Restronguet noticed that he was gaining rapidly on his rival, and had been unable to account for the rapid decrease in the intervening distance unless Karl von Harburg had lighted upon an isolated spot that seemed to suit his requirements.

At Kaira Captain Restronguet was able to procure an old though fairly reliable Portuguese map of the course of the river, and on this the position of the rival submarine was carefully noted. If she succeeded in floating and proceeding up the Zampa River it was evident that the "Vorwartz" would soon be in British territory--the colony of Rhodesia.

That same evening a wireless message--the first for three days--was received from Captain Restronguet's English agent stating that the Foreign Office was in communication with the government of the Portuguese Republic, and an arrangement had been arrived at whereby three British sternwheeler gunboats that were used to patrol the Shiré River, were to be allowed to descend to the Zambezi and attempt to cut off the "Vorwartz" on her return.

"Evidently the British Navy wants to chip in at the death," commented Captain Restronguet. "We must look to our laurels. It would be hard lines to be searching for days amongst these unexplored backwaters without success, and to find that one of these little paddle-boats by a piece of sheer good luck had managed to blow the 'Vorwartz' to smithereens while she was lying helplessly stranded on a mud-flat."

Hythe did not reply. He was naturally anxious, now that he had been on board the "Aphrodite" for such a lengthy period and had faced perils in company with her crew, that Captain Restronguet should receive a just reward for his strenuous endeavours; yet he did not forget that he was still an officer of the great British Navy, whose policy is to be ready, aye ready, in the hour of triumph or in the hour of disaster alike.

Just then Carnon, who since Kenwyn's illness had been appointed solely for duties in connexion with the detector, approached and saluted.

"The detector, sir, has gone wrong," he reported.

"Gone wrong? What do you mean? Have you been tampering with the instrument?"

"No, sir. The last reading gave sixty-one miles. That was five minutes ago. When I looked again there was no record at all. The batteries are still working: I could get a spark an inch in length. The terminals are properly clamped."

Captain Restronguet, Devoran, and the sub hastened to the compartment in which the detector was fixed. The indicator board was absolutely blank.

"We're not having an easy time of it at all," remarked the captain. "Without the detector it is quite possible that the 'Vorwartz' may yet outwit us. All the same, I cannot understand it."

"We know her position up to ten minutes or a quarter of an hour ago, sir," said the first officer.

"Quite so, Mr. Devoran; and we must work on that. It will take us three hours, running at the highest speed compatible with prudence in this brute of a river, to arrive at the spot where the 'Vorwartz' was last reported. In three hours Karl von Harburg may have shifted a long distance off--or he may not."

"And there's Kenwyn to be taken into account."

"I haven't forgotten him. I think after all we had better keep him on board. It is too much of an undertaking for two men to have and tend him, provide for themselves, and be on their guard against the wild animals that abound, and a dozen other difficulties that a camp on shore would entail. However, pass the word for a speed of twenty-four knots. Allowing for the adverse current we ought to be at the confluence of the Zampa River well before sunset."

Just above the town of Shemba the Zambezi bifurcates, the two streams reuniting twenty miles higher up. It was just possible that the "Vorwartz," bound towards the sea, might be passing down one branch while the "Aphrodite" was proceeding up the other; but this time luck was in Captain Restronguet's favour, for above the junction the "Aphrodite" fell in with a trading steamboat, whose captain, by signs, made it clear that no vessel of any description approaching the "Vorwartz" had passed down the left-hand stream.

The river here was considerably narrower and deeper than nearer its mouth. Its width was still over half a mile, while the soundings gave a level bed of six fathoms. Here, also, the tide was no longer felt; but, owing to a cessation in the rainfall, the level of the river was gradually sinking.

During the course of the day several canoes passed at a respectful distance; but late in the afternoon a craft of some sort was sighted drifting down in mid-stream.

As the "Aphrodite" approached it was seen that the object was a raft composed of several slender spars supported by four barrels, to which were lashed four or five short planks. Lying on the platform thus formed were two human bodies.

"What do you make of it, Mr. Devoran?" asked Captain Restronguet. "A tragedy--not exactly on the high seas--but one of a very extraordinary nature. They look like Europeans."

"Shall I have the boat lowered to investigate, sir?"

"No, they're dead right enough. I've been watching them pretty carefully through my glass for some time. If it's a case of contagious disease we had better sheer off."

"Why, they're Chinese!" exclaimed Hythe.

"Chinese? Then they must be some of the crew of the 'Vorwartz'," said Captain Restronguet. "Evidently von Harburg has met with disaster."

As the submarine passed the aimlessly drifting raft a fairly close view could be obtained of the dead Chinamen. They were dressed in blue cotton suits after the style affected by Chinese seamen serving in European vessels, but there was no mistaking the Tartar features and the slanting eyes. That they were stone dead there could be no doubt, for there were several birds hovering around the raft in a manner that their natural timidity would not permit if the two bodies showed signs of life.

"Do you think that a catastrophe has occurred to the 'Vorwartz,' sir, or were these men merely attempting to escape?" asked the sub.

"Coupled with the fact that our detector has failed to give any indication of the 'Vorwartz,' I am inclined to favour the first theory," replied Captain Restronguet. "Since our apparatus is, as far as I can tell by careful examination, in perfect working order, I can only put its unresponsiveness down to the failure of the electric current on board the 'Vorwartz.' That, of course, would account for the failure of our detector."

"And the 'Vorwartz' could otherwise be capable of action?"

"To a certain extent. But without electricity she can have no means of compulsion, no means of offence, unless we except the use of fire-arms. However, before to-morrow is past we ought to discover her whereabouts. I am not proceeding further to-day as night is approaching. As soon as we find a suitable depth we'll descend till morning."

Another night passed without interruption. The detector was still silent, but the "Aphrodite" was now within a few miles of the spot where the "Vorwartz" had last given notice of her presence.

It was not a desirable day. Torrential rains were falling, while the atmosphere was too close to wear oilskins without the greatest discomfort. Consequently on the "Aphrodite" rising to the surface her crew save three had to remain below.

Captain Restronguet, Hythe, and Carclew were in the for'ard conning-tower, Devoran, Carnon the quartermaster, and Polglaze occupied the after conning-tower, so as to maintain a careful look out on all sides. Three men, braving the heavy downpour, were stationed for'ard, where they took turns in casting the lead.

The river here was considerably narrower--about thrice the width of the Thames at London Bridge. The banks on either hand were low and densely covered with thick scrub and extensive forests of tropical trees; while the skyline was broken on both sides by serrated ridges of lofty mountains.

"This must be the Zampa River," said Captain Restronguet, pointing to a fairly wide waterway that joined the Zambezi on its right bank. "Here the 'Vorwartz' was sighted by the natives. It would be well to explore the stream before going further."

"It looks too shallow to take anything more than a flat-bottomed light-draught vessel," remarked Hythe. "Still, as you say, sir, we ought to leave nothing unexplored behind us. If you wish I will take charge of the whaler and see what it is like."

"Very good, Mr. Hythe. I shall be obliged if you will. We'll remain here. Do not proceed further than there is depth for the 'Aphrodite' to follow. Should you require assistance fire three explosive rockets. If anything should necessitate your immediate return I will make a similar signal. Should you locate the 'Vorwartz,' endeavour to return without being seen."

It certainly required plenty of zeal to volunteer for a boating expedition on a tropical river in such torrential rains, but the men called upon for the service responded with alacrity.

Four rowers stripped to the waist sat on the thwarts, apparently quite indifferent to the rain. Hythe, Polglaze, and Carclew were in the stern sheets, partially protected by an awning, but before the whaler pushed off the canvas covering, sagging under the quantity of rain water, was found to be of more trouble than use, for a regular stream poured through the canopy upon the sub's head and shoulders. Since it was also likely to attract the attention of Karl von Harburg's men Hythe ordered it to be struck, and accepting the situation as well as he could, was soon soaked to the skin.

The tributary was found to be nearly twenty feet deep towards the right-hand bank. On both sides were belts of malodorous mud on which numerous crocodiles were lying as if enjoying the rain. Others, looking more like floating logs, were drifting in the channel, and careful steering was needed to avoid them. Hythe realized that he was not on a sporting expedition, and should any of the saurians become infuriated it would be necessary to fire at the reptile. The report of the rifle would give the alarm to the "Vorwartz" should she be within hearing, and the chances of locating her without being discovered would be very remote.

For more than a mile the rowers toiled manfully. The current was strong, the boat heavy, while Polglaze had to bale incessantly to prevent the rain from rising over the stern gratings. The "Aphrodite" was now lost to view by an intervening bend in the course of the stream.

The depth still continued regular, and afforded plenty of water for a craft like the "Vorwartz" to ascend if her ballast tanks were emptied, but as reach after reach was opened out no sign of the rival submarine was visible--only a monotonous stretch of coffee-coloured water enclosed on either hand by the soft stagnant mud that effectually prevented any attempt at landing.

"What's that, sir?" asked Polglaze, suddenly holding up his hand and listening attentively.

"Lay on your oars, men," ordered the sub.

Above the hissing of the rain Hythe could distinguish the deep purr of a powerful motor. Could it be that the "Vorwartz" was returning? If so, escape was impossible, for no cover of any sort was obtainable, and long before the whaler could return to the "Aphrodite" she would be overtaken by the swiftly moving submarine.

"It's that brute of a von Harburg coming downstream, sir," exclaimed Carclew. "We're fairly trapped."

In reply the sub ordered the boat to be turned and her head pointed down stream. Drawing the three detonating rockets from a locker under the stern sheets he rapidly lashed the sticks in position. Happen what may the "Aphrodite" must have warning of her enemy's approach. Perhaps, as the "Vorwartz" was now under way her electrical current would operate the detector onboard the "Aphrodite"; if so there was every reason to suppose that Captain Restronguet was already on his way to rescue his whaler's crew and engage his sworn foe. A chance of safety yet remained.

"Give way, men," ordered Hythe. "We may do it yet."

Nearer and nearer came the throb of the powerful motors. Hythe grasped the lanyard of the nearest rocket. He hesitated. There was something in the sound of the motors that could not be associated with a submarine, even allowing for the conductive properties of the water; it was more like the drone of an aerial propeller.

The next instant the snub nose of a large airship appeared round the bend of the river. The vessel was flying low; her two suspended cars were not forty feet above the surface. Her yellow silk envelope was literally streaming as the rain descended upon it in torrents, and this was why, Hythe reasoned, she was flying so low.

The sub ordered the whaler's crew to cease rowing and soon the airship was overhead. Her engines were reversed, and losing way she brought up just in front of the boat. Hythe saw with feelings of relief that aft the airship was flying a Blue Ensign with a yellow propeller--the badge of the recently constituted British Empire Aero-League--emblazoned on the flag. Half a dozen men were leaning over the rail of the platform connecting the two cars.

"What boat is that?" hailed a tall, sparsely-built man dressed in a white uniform.

"The 'Aphrodite' submarine, Captain John Restronguet," replied Hythe without hesitation. "What airship is that?"

"The 'Pride of Rhodesia,' of Salisbury. Is Captain Restronguet in the boat?"

"No," replied Hythe. "He is on board the 'Aphrodite' lying at the junction of this river with the Zambesi."

"And who are you, sir, might I ask?"

"Arnold Hythe, Sub-lieutenant of the Royal Navy."

"So you are the Mr. Hythe we've heard so much about? Glad to meet you. Sorry we can't shake hands; must delay that honour till a more convenient time. I'm Jones of Salisbury, Rhodesia, and we're having a chip-in with that villain, Karl von Harburg. I suppose we are not too late?"

"Seen anything of her?" asked Hythe. "We are exploring this river in the hope of finding her brought up."

"May as well give it a miss," replied Captain Jones of the "Pride of Rhodesia." "We've followed the whole of the navigable part of this ditch. We've also reconnoitred the Mali, the Tutti, and the Baraloo; the Zampa we didn't trouble about; it's too narrow to take a craft the size of the 'Vorwartz.'"

The sub felt like shaking hands with himself. The airship had purposely overlooked the river in which the "Vorwartz" had been reported. Captain Restronguet had made a mistake in thinking that this river was the Zampa.

"Well, I wish you luck," he said truthfully, for there can be various qualifying conditions to the subject of luck. "By the by, what's the name of this river?"

"The Pongo," replied Captain Jones. "It rises in Rhodesia not so very far from the frontier of the Portuguese territory. I reckon we've saved you a bit. We'll save you more yet if you wish. We'll tow you down stream. I'm curious to see the renowned 'Aphrodite.' Captain Restronguet won't object, I suppose. Will you come aboard--we'll drop a rope-ladder."

"No, thanks," replied Hythe. "We won't come on board. We cannot get much wetter if we stay here. All the same, we shall be glad of a tow."

The sub was cautious. He did not wish to be kidnapped a second time, and not knowing who Captain Jones was or whether the "Pride of Rhodesia" was a bona fide craft belonging to the British Empire Aero-League, he thought it advisable to decline the invitation to board the airship.

A coil of rope whizzed from the after platform of the overhead vessel. It was caught and made fast by the bowman, the "Pride of Rhodesia's" huge propellers began to revolve and soon the "Aphrodite's" whaler was being towed down the stream at a good ten knots.

"Pass that rope aboard the 'Aphrodite,' please," shouted Captain Jones as he brought the boat alongside the submarine. Captain Restronguet waved his hand in token of assent and soon the airship was riding head to wind with her nacelles just resting on the water.

Hythe hurriedly explained the circumstances under which he had fallen in with the airship, mentioning that he had found out by accident that it was not the Zampa River that he had explored after all.

"That's good," commented Captain Restronguet enthusiastically. "We can well afford to be disappointed. This Captain Jones told you he didn't mean to explore the Zampa, eh? Well, we'll have him on board, since he evidently desires it, but we must be careful not to drop the faintest hint concerning our information that the 'Vorwartz' was known to have entered that river."

The boat was dispatched to bring Captain Jones on board the "Aphrodite," and soon the owner and commander of the "Pride of Rhodesia" stood upon the deck of the submarine. He was a fairly young man, still under thirty, and full of almost boyish enthusiasm.

"We seem to be sort of friendly rivals," he remarked. "I don't want to boast, but I think I stand the better chance. Had that German scoundrel kept to the sea the odds would be in your favour, but since he is in comparatively limited and shallow waters he cannot submerge his 'Vorwartz.' But aloft I can command a vast extent of country, while you have to grope about, if I may say so."

"I quite see the point of your argument," replied Captain Restronguet drily. "But, might I ask, what do you propose to do when you find the 'Vorwartz'?"

"Oh, we are armed," said the Captain of the "Pride of Rhodesia." "We carry two bomb-dropping devices, besides four quick-firers. We are subsidized by the Government and authorized to carry offensive and defensive weapons. Directly we spot the 'Vorwartz' I shall have no hesitation in dropping a fifty pound charge of dynamite and blowing her to atoms."

"Dropping, you say? I understand that you cannot do otherwise than allow the bombs to fall simply by the action of gravity?"

"That is so," assented the owner of the airship. "But I think there is little possibility of their missing the mark. We took first prize at the Johannesburg Aero-Exhibition last year, placing six dummy bombs within a space eighty feet by twenty, and that from an altitude of five hundred feet."

"And your quick-firers?"

"Three-pounders."

"Not heavy enough to penetrate the plating of the 'Vorwartz,' I can assure you. Now, what do you think Karl von Harburg will be doing while you are manoeuvring to be in a position to drop one of your bombs immediately overhead?"

"I don't know," replied Captain Jones. "Why--do you?"

"Step below and I will show you a weapon that is almost identical with one carried by my rival. As you are probably aware, Karl von Harburg applied several of my inventions to his own use."

Captain Restronguet led the way below to where the aerial torpedo gun was housed.

"Here is a weapon capable of being trained fifteen degrees in any direction from a vertical," he explained. "Even when submerged to a depth of fifty feet I can discharge a projectile and hit an object a thousand feet in the air. The bursting charge throws out a shower of shrapnel with such force that no air-craft, within a radius of two hundred yards from the point of explosion, could possibly survive."

"By Jove!" ejaculated Captain Jones, his bronzed skin turning a lighter shade. "I didn't know the 'Vorwartz' carried anything like that. But no matter," he added cheerfully. "It is the fortune of war either way. I mean to do my duty in ridding the world of a pest, and if I fail it won't be for want of trying."

"Hear! hear!" exclaimed Hythe, while Captain Restronguet brought his hand down heavily upon his friendly rival's shoulder.

"That shows the British bull-dog spirit isn't dead yet," he remarked. "I am glad to hear you speak thus. You do your best: I'll do mine, and may the better man win."

The commander of the airship was shown over the "Aphrodite" and all except the essential details of her construction were minutely explained by his host. The inspection wound up with refreshments in Captain Restronguet's cabin, and in reply to an invitation Captain Restronguet, Hythe, Devoran, and Jenkins went on board the "Pride of Rhodesia." For an airship she was certainly a novelty, being built and engined in Rhodesia and of Rhodesian material--a striking testimony to the growth of one of Britain's youngest children.

Curiously enough the airship was subdivided into three compartments similar to the "Aphrodite." Thus, in the event of an accident to any two of the sections the third would be quite capable of supporting the crew and acting as a balloon; while, should the afterpart remain uninjured, it would still be able to be driven by the motors which were situated just abaft the division between the second and third sections.

"By the by, how do you combat with the deadly night airs?" asked Captain Restronguet.

"We ascend to about three thousand feet," replied the owner of the "Pride of Rhodesia." "It's a splendid climate up aloft; a guaranteed cure for all sorts of tropical fevers. How do you manage?"

"Oh, we dive," was the reply. "Our air supply is quite independent of outside atmosphere. But night is approaching, we must return."

Had there not been an element of danger should the airship attempt to combat the "Vorwartz" Captain Restronguet would have requested that Kenwyn should be temporarily accommodated on board so that the bracing air would aid his recovery, but under the circumstances he preferred to keep his second officer in the submarine.

Shaking hands Captain Restronguet and his companions bade their friendly rivals farewell and boarded their whaler. On the way back Hythe asked Jenkins what he thought of the "Pride of Rhodesia."

"Not much," replied the chief aviator to the Sultan of Zanzibar. "Not much. If I had my three-seater monoplane and a couple of hands I'd guarantee to knock spots off her as easy as kiss your hand."

"As Captain Jones said, the odds are in his favour," commented Captain Restronguet. "All the same I admire him. It will be a race for a coveted prize. Let the best man win by all means, but as sure as my name's what it is I'll do my level best to go one better than the 'Pride of Rhodesia.'"

CHAPTER XXX.

CAPTURED.

An hour after sunrise the "Aphrodite" came to the surface. The rain had ceased, the mists had rolled away, and the slanting rays of the sun, already powerful, beat fiercely down upon the coffee-coloured surface of the river. There was no sign of the "Pride of Rhodesia." She had taken herself off betimes.

"I hope she has continued her investigations down stream," said Captain Restronguet. "It was a lucky chance that Jones mentioned to you about not considering the Zampa worthy of his notice. We'll just have a look round and see if the 'Vorwartz' has found room enough to stow herself away in that little ditch."

"A wireless message has just come through, sir," said Devoran. "The 'Swallow,' 'Puffin,' and 'Sandpiper,' three stern-wheeler gunboats from Lake Nyassa, have descended the Shiré and were reported to the Admiralty as having reached Sena yesterday."

"The more the merrier," commented his superior grimly. "They ought to be here this afternoon if they kept under way all last night. We must bestir ourselves. I think before we do anything else we ought to put Kenwyn ashore. You see that knoll on our left, Devoran? It stands fairly high, and should be pretty healthy; in daytime, at all events. We'll land him and his two nurses and pick them up on our return."

Captain Restronguet spoke as calmly as if he were going on an excursion instead of about to engage in a desperate encounter with his implacable foe. Hythe understood his manner better by this time. He knew that when Captain Restronguet meant business he always adopted a resolute bearing. The magnetic personality of the man more than half won his battles.

An awning was rigged in the whaler, and under this, Kenwyn, lying in his cot, was placed. Mylor and Lancarrow accompanied him, while the boat's crew, thoroughly disinfected to prevent contagion, rowed them to the steep bank of the isolated hill the captain had pointed out. The ascent took some time, and the boat's crew had received instructions to rig up a tent and make everything snug for the patient before returning.

Looking through their binoculars Captain Restronguet and Hythe watched the tedious procession. At length Kenwyn was carried to the summit and placed in the shade of a solitary tree. Apparently this site did not suit, for Mylor was observed to be pointing to a clump of densely-foliaged trees on the north side of the knoll. The boat's crew raised objections, since time was precious, and the argument ended by Mylor and two others carrying the tent across to the clump and leaving the others with the sick man. Before Mylor gained the desired position the rest picked up the cot and followed.

"I can see the objection to Mylor's plan," remarked Captain Restronguet. "They will be hidden from the river everywhere except from this bearing. However, it is well to windward, and ought to be fairly pleasant under the shade of the trees. But I wish those fellows would bestir themselves a little more."

Presently Mylor disappeared from view behind the trees. He had not been gone very long before he returned to his companions running as hard as he could go. A few words passed and the whole crowd, leaving Kenwyn lying in the shade, doubled off behind the clump.

"Now what's up," muttered the captain impatiently. "I wish I had sent Devoran with them to keep them together. They are like a pack of schoolboys out of bounds."

Back came the men, never pausing till they reached the brink of the hill on the river side. Here Mylor, standing well apart, began to "call-up" the "Aphrodite" by semaphore.

"Acknowledge, Mr. Devoran," said Captain Restronguet.

Clambering on to the top of the conning-tower the first officer signalled that attention was being paid to the message.

"'Vorwartz' is lying on the other side of the hill," semaphored Mylor.

"What's that? Impossible!" exclaimed the captain, for both he and Hythe had read the message correctly. "Ask them to explain more fully."

"'Vorwartz' is in a river flowing behind this hill."

"Boat's crew to return instantly," ordered Devoran at Captain Restronguet's request. "Leave Kenwyn and his two men."

"I hope they didn't let those on the 'Vorwartz' see them," said Captain Restronguet. "If it be the 'Vorwartz'--and I have no reason to suppose that there is another submarine beside her and the 'Aphrodite' on the Zambezi--we have just saved ourselves from being nicely fooled. We might have been searching the tributaries on the right bank till Doomsday."

"And the 'Pride of Rhodesia' is devoting her attentions to the right bank also," added the sub.

"Let her," said Captain Restronguet with a hearty laugh. "This seems almost too good to be true."

Bending to their oars and heedless of the blazing sun the whaler's crew brought the boat back at breakneck speed. Almost before her way was checked as she came alongside Captain Restronguet, Hythe, and five of the crew leapt on board. They had taken the precaution to arm themselves, for it was quite possible that some of Karl von Harburg's men had gone ashore and had already sighted the "Aphrodite" lying in mid-stream.

Up the hill the landing party toiled, and crossing the plateau gained the clump of trees on the landward side. Here they hid, while Captain Restronguet and the sub reconnoitred by means of the binoculars.

Yes, there was no longer any cause for doubt. The twin conning-towers and a portion of the upper deck of the "Vorwartz" were just visible above the reeds that fringed the narrow river. She was floating high, all her ballast tanks having been started. Two of the hatches were flung back but no signs of any of the crew were to be seen.

"She's hard aground, I think," observed Hythe. "The river has fallen in spite of the rains, and she's fairly caught."

"I wouldn't like to say that such is the case," replied Captain Restronguet. "It seems to me that they are lying low: shifting some of their booty to a safe hiding-place. At all events I don't feel inclined to take the 'Aphrodite' up the stream. I'll get Devoran to lie off the junction of this river with the Zambezi. If the 'Vorwartz' attempts to escape he can easily sink her in shallow water. Meanwhile I'll have the field gun landed. Firing capped shell she will be able to hull yonder craft through and through. All the same I cannot account for the lack of signs of life aboard."

Captain Restronguet left nothing to chance. In order to guard against a possible surprise he had outposts placed at proper distances from his main body. Hythe volunteered to superintend the landing of the field-gun, and in less than an hour that piece of ordnance was by dint of sheer hard work brought ashore and hauled to the top of the hill. Here it was placed in position, carefully screened by the trees, and its muzzle pointed menacingly upon the visible part of the "Vorwartz."

Another hour passed. Still no signs of activity were noticeable on board the rival submarine.

"Would you mind taking two men with you and creeping down as near as you can get to the 'Vorwartz,' Mr. Hythe?" asked the Captain, who was beginning to get impatient. "Take every precaution to keep hidden from view and do not use your fire-arms save as a last resource."

"Very good, sir," replied Hythe.

"I need hardly remind you that I want evidence. Observe traces of footmarks on the banks. They ought to tell whether the crew have landed. If they have put their precious cargo ashore there must be traces of where the heavy chests and bags were hauled over the banks; the reeds will be trampled down, and so on."

Had Hythe not been a sailor he would have made an excellent backwoodsman. Knowing the risk of appearing on the skyline, he led his little band down by the remote side of the hill, and creeping through the bushes at the base gradually worked round in the direction of the river in which the "Vorwartz" lay.

It was risky work, for the lower ground was marshy. Poisonous snakes darted across their path, lizards, more repulsive than dangerous, lay basking in the sun right in their way, while myriads of flies of great size buzzed incessantly over the men's heads, till the tortured three could scarce resist the temptation to raise their arms and beat off their unwelcome attendants. Once a heavy body crashed through the brushwood, scattering the reeds in all directions and uprooting young saplings like ninepins. Hythe had just time to see that the creature was a huge rhinoceros.

Straight towards the "Vorwartz" the creature tore, then plunging into the opposite stream swam boldly across to the opposite bank. Although it made enough noise to be heard for half a mile away the crew of the "Vorwartz" showed no sign of activity. The submarine lay as deserted and silent as the city of the dead.

"Steady, there," cautioned Hythe as one of his companions started forward with disregard to caution. "They may be luring us on. We are near enough at present."

Concealing themselves in the long grass fringing the river, even at the risk of fever, the three waited and watched. The "Vorwartz" was lying close to the bank, the channel evidently trending close to the eastern side of the stream, and there being a total absence of mud in the vicinity, the submarine could not have found a better landing-place.

She was secured fore and aft with ropes made fast to the trunks of trees growing close to the water's edge. No anchor had been run out into the stream and consequently the submarine had swung well in. A fall in the level of the river had left her fairly hard aground with a slight list to port.

That men had landed during the heavy rains was quite evident by the fact that the stiff clay, now burned to the hardness of a brick, was covered with footprints pointing in all directions, but although Hythe made a semi-circular patrol almost from the brink of the stream past the "Vorwartz" and back to the river again he could find no trace of human beings having strayed more than fifty yards from the submarine.

"Strange," he muttered. "The craft looks deserted and there are no signs of the rascals making off by land. They couldn't very well travel by air, so the only solution is, unless they are still on board, that they have gone by water. How? By boat or walking in their diving dresses? By boat, I suppose, since if they decided to abandon the vessel they would naturally take part if not all of their precious booty with them."

At length so convinced did the sub become that the "Vorwartz" was in truth deserted that he felt sorely tempted to take possession of her. But his sense of discipline prevailed. He realized that temporarily he was under Captain Restronguet's orders and to Captain Restronguet alone ought the honour to be given to be the first to board.

He was on the point of ordering the men to retire when a violent rustling in the reeds attracted his attention. Either a human being or an animal was approaching. He motioned to his companions to be on the alert. Holding their rifles at the ready the two men waited.

Suddenly a man lurched forward from the edge of the reeds. He was literally in rags, fragments of blue clothing scarcely concealing his massive limbs. He was hatless, a strip of dirty white linen alone protecting his head from the pitiless rays of the sun. In the holster of his belt was a revolver, while his right hand grasped a magazine carbine.

"One of the villains; shall we nab him unawares, sir?" asked one of Hythe's men in a whisper.

The sub shook his head. The fellow was armed; he might not be alone, while the discharge of a fire-arm might give the alarm to a still unsuspecting foe. Better to watch and see what the fellow was up to.

The new-comer lurched as if spent; but without any attempt to conceal his movements he made straight for the "Vorwartz." At the edge of the bank he hesitated, walked to and fro as if looking for a shallow spot or a means of clambering up the side of the vessel. Finding none he hurled his carbine against the submarine's side, shivering the stock into fragments. Then uttering a demoniacal yell he broke into a ribald song in German.

The man was mad.

"Karl von Harburg?" whispered Hythe interrogatively.

The seaman nearest him shook his head. He knew the captain of the "Vorwartz" well by sight during his stay in Sumatra. This fellow was a stranger.

"Heave a rope!" hailed the German in his native tongue. "Heave a rope! I want to get on board and fetch more gold. Yes, more gold, I say. I'll carry another load of it myself. Fritz took two shares; why shouldn't I?"

Receiving no reply the maniac whipped out his revolver and emptied the contents of the chambers against the metal plating. The noise of the firing was heard by Captain Restronguet and the main body. They could not see the German's approach by reason of the intervening fringe of long grass; but suspecting that Hythe had been attacked they raced down the hill to his aid.

Springing to his feet Hythe signed to them to continue cautiously, but the madman, although he must have heard the noise of the new arrivals, paid no attention. He was still cursing imaginary comrades for their laxity in not giving him a means of getting on board.

"What has happened?" asked Captain Restronguet breathlessly.

"One survivor only, I think," replied Hythe. "There he is. He's absolutely off his head."

"Are you sure there are no more on board?" asked the captain.

"Not certain, but I don't think there are. Do you wish me to make that fellow a prisoner or wait till he's on board? He hasn't reloaded his revolver and he's thrown his carbine away."

"We'll wait," said Captain Restronguet decidedly. "Perhaps there are others on board and they've quarrelled. That may be the reason why they are lying low and won't let this fellow on board. Now look at him!"

The maniac put one foot in the water with the intention of wading close to the submarine's side, but at the contact with the fluid he leapt back, held his foot with both hands and hopped about uttering discordant shouts as if the water pained him. Then, calming down a little, he seated himself on the shore and began to sob like a child.

"Now's our chance," whispered Captain Restronguet. "We must risk a few rifle shots from on board. You three men--that will be enough. Now follow me and get him on his back before he's aware of it."

Noiselessly the three men followed their captain. Forty yards of open ground separated them from their intended captive. Nearly half this distance was covered when the madman suddenly rose and looked over his shoulder. His wild glance fell upon his would-be assailants.

"Bowl him over," shouted Captain Restronguet, breaking into a run.

The German waited apathetically till the nearest of his foes was within ten yards. Then, uttering a wild unearthly laugh, he turned and dashed headlong into the river. Half a dozen strokes brought him to the stern of the submarine. Here he tried to haul himself up, clinging tenaciously to the slight support afforded by the upper edge of the propeller brackets. Baulked in this direction he slipped back into the water and swam to the other side of the "Vorwartz."

By this time the whole of the landing party arrived on the scene. Half a dozen powerful men tailed on to the stern warp till it was almost as taut as a bar of steel. Two others, one being O'Shaunessey, grasping the rope with both hands and throwing their legs round it began to make their way towards the submarine; but before they had swung themselves over half the distance the maniac appeared on deck.

Once more drawing his revolver, from which the moisture dripped copiously, he steadied it in the crook of his arm and pressed the trigger. The hammer clicked harmlessly on the empty chambers. With a snarl of rage the German hurled the useless weapon not at the two men hanging on to the rope, but at the group ashore. It whizzed perilously close to Captain Restronguet's head, bouncing on the sun-baked mud.

"Attract his attention," ordered Captain Restronguet. "Try to entice him towards the bows and give those fellows a chance to board."

Picking up lumps of hard mud the "Aphrodite's" men opened a heavy yet comparatively harmless fusillade upon the solitary figure upon the deck of the "Vorwartz." Still keeping up his discordant yells the madman stooped and picked up an object at his feet. With wellnigh superhuman force he hurled it at his assailants. The missile fell at Hythe's feet. Something prompted him to stoop and examine it. It was an ingot of pure gold.

"By Jove!" he exclaimed. "I never had gold thrown at me before!"

His remark attracted the attention of the men nearest to him.

"Keep it up, old sport," shouted Carclew. "We don't mind."

The next instant he had cause to regret his words, for a lump of the precious metal, hurtling through the air with tremendous force, hit him fairly in that part of his anatomy commonly known as "the wind." For the next ten minutes Carclew lost all interest in the proceedings.

Meanwhile O'Shaunessey, unobserved by the madman, succeeded in clambering over the stern of the "Vorwartz." Here he waited till his comrade rejoined him, and together they stealthily crept towards the German.

The fellow was in the act of hurtling another missile when O'Shaunessey sprang on him from behind, flung his powerful arms round the madman's head and pressed his right knee into the small of the man's back. Simultaneously the Irishman's comrade grasped the astonished German just below the knees, and with a tremendous crash the captured man fell upon the metal deck. Even then his captors had no easy task, for the maniac, powerful under ordinary circumstances, now possessed the strength of ten. His right hand gripped O'Shaunessey's calf till the Irishman bellowed with pain. For a few moments it looked as if the madman would be more than a match for his two antagonists till O'Shaunessey's companion, loth to run any unnecessary risk, planted a heavy blow on the point of the madman's chin. The fellow's resistance ceased. He lay on his back groaning dismally, while the Irishman deftly bound him hand and foot with a couple of silk handkerchiefs.

"All clear now, sorr," shouted O'Shaunessey. "Sure, you can come aboard aisy and comfortable. We'll heave a line."

Looking about the Irishman discovered a wire ladder and a couple of long boat-hook staves. Lowering the former he swarmed down and succeeded in passing the end of one of the boat-hooks ashore, keeping the other end on the bottom rung of the ladder. The second one formed a handrail, and along this precarious bridge, which sagged to such an extent that those making use of it were ankle deep in water, Captain Restronguet, Hythe, and four of the "Aphrodite's" crew made their way.

"At last, sir," exclaimed Hythe.

"It is yet too early for congratulations, Mr. Hythe," replied the captain. "We have made an easy capture, but until I am face to face with my enemy, Karl von Harburg, my mission is not at an end. Nevertheless, we have much to be thankful for. Polglaze, bring that boat-hook aft."

The man did as he was ordered. Drawing from his pocket a small neatly-rolled bundle of silk Captain Restronguet unfolded it. It was his white and green ensign with the initials "J. R." upon it. For want of halliards the flag had to be lashed to the stave, which was thereupon set up on the stern of the "Vorwartz"--a visible token that the rival submarine was now in the possession of the captain of the "Aphrodite."

CHAPTER XXXI.

THE UNSUCCESSFUL COMPETITORS.

Hardly had the echoes of the three ringing cheers that greeted the hoisting of the ensign died away than the distant throbbing of an airship's motors was heard. Just appearing over the knoll was the "Pride of Rhodesia."

"Hope they won't start dropping bombs on us," exclaimed Polglaze.

"No fear of that," said Captain Restronguet reassuringly. "They've seen our ensign. They're dipping theirs, by smoke!"

Slowly the Blue Ensign at the stern of the air-ship was lowered and as slowly rehoisted. Unable to "dip" in the orthodox way the green and white flag was lowered staff and all.

Then majestically the huge yellow enveloped craft eased up till just holding her own against the light breeze, sank gently towards the earth, alighting on the sun-baked ground within twenty yards of the captured submarine.

"The best man has won, sir," exclaimed Captain Jones, raising his white cap. "I heartily congratulate you."

"More by good luck than anything else," returned Captain Restronguet modestly. "If I hadn't sent a sick man ashore we might never have spotted her stowed away so snugly behind the hill. I suppose you've seen nothing of the crew?"

"Her crew?" repeated the Captain of the "Pride of Rhodesia." "Why, haven't you bagged the whole crowd of rascals?"

"Only one," replied Captain Restronguet. "Much to my sorrow and regret."

"Never say die," was the cheerful response. "Now you've captured the 'Vorwartz' what are you going to do with her?"

"I haven't given the matter a thought yet. She's hard and fast aground. Even if we floated her, I don't know how we could manage to get her down to the sea or what to do with her when we did."

"You'll have plenty of help in an hour or so," announced Captain Jones. "That is, if you want any. There's a regular flotilla of stern wheelers coming up stream. They're flying the British Ensign."

"I heard they were on their way up," said Captain Restronguet. "They are from Lake Nyassa. Let 'em all come, as the catch-phrase used to be when I was at school."

"Look here," said the airship's owner. "If you like I'll stand by and lend a hand. Please understand I don't want to take away any credit that belongs to the 'Aphrodite' alone; neither are we after a share in the prize money, although I hear the 'Vorwartz' is chock full of gold. That's what's keeping her hard and fast, I should think."

"You are awfully good," replied Captain Restronguet. "I shall be only too happy to avail myself of your services."

"And the sooner the better," added Captain Jones. "Five additional helpers, all used to plenty of hard slogging, will soon make a show."

Telling Polglaze to make his way back to the spot where they had landed from the "Aphrodite," in order to let Devoran know that all was well, Captain Restronguet, accompanied by Hythe and Captain Jones, began a systematic examination of the captured submarine. Except for the maniac, who was now babbling in a childish manner and was quite unconscious of his surroundings, not a man of von Harburg's company remained. Everything on board showed signs of a hurried departure. In the galley the men's dinner was still in the boilers. The electric power had apparently failed, for some time since a temporary stove for burning wood had been erected in the galley, the funnel leading through the open fore hatch. By examining the thickness of the deposit of soot Captain Restronguet was able to come to the conclusion that the failure of the electrical supply coincided with the time the "Aphrodite's" detector ceased to record the position of her rival.

Stowed away in the emergency water ballast tanks were hundreds of bars of gold--plundered from many a richly-laden vessel. This horde had not been touched, but almost all the specie and bullion in the after cabins had been removed.

"What prompted the rogues to make such a hasty flight, do you think, sir?" asked Hythe.

"They undoubtedly got wind of the news that we were on their track. The failure of their electrical gear added to their panic. They decided to remove as much of their plunder as they could conveniently carry, and trust to luck that the rest of the booty remaining on board might yet be recoverable. I think they must have gone up stream in a boat, since there are traces of their footprints through the grass."

"You mean to pursue your search?" asked Captain Jones.

"Certainly," replied Captain Restronguet with conviction.

"Judging by the state of the river," continued the captain of the "Pride of Rhodesia," "which is still falling, even a boat expedition will be a difficult matter. Why not make a voyage in my craft? We can follow the course of the river at any height you wish, and if Karl von Harburg has attempted flight by means of a boat we shall be bound to overtake him and effect his capture. I can easily find room for a dozen of your men."

"I will gladly accept your offer," replied Captain Restronguet without hesitation. "When will it be convenient for you to start?"

"At once," replied Captain Jones promptly. "We ought to complete the business and be back here well before night. Meanwhile those of your men who are left behind--I will leave some of my crew as well--can proceed with the unloading of the 'Vorwartz.' The gold will be perfectly safe ashore, for there do not seem to be any inhabitants in this district. Even if there are, and they are tempted to give trouble, twenty rifles firing from the deck of the submarine will make them keep a respectful distance."

"Come along, Mr. Hythe; this will be another experience for you," said Captain Restronguet. "Carnon and Carclew you will come with us. Eh? What's that? Mr. Hythe, here's your Irishman anxious to have an aerial trip."

Ascending the swinging ladder the men gained the platform connecting the two deck-houses of the airship. Hythe found himself on a promenade nearly three hundred feet in length and forty in width converging fore and aft, and terminated by the aluminium cabins that afforded sleeping accommodation for the crew and also means of manoeuvring the airship in bad weather.

"Cast off there," shouted Captain Jones.

Those of the airship's crew who remained ashore hastened to unfasten the stout hempen hawsers that held the "Pride of Rhodesia" to the ground. Since the total number of men on board was less than that of the present crew no throwing out of ballast was necessary. The airship rose swiftly and smoothly to a height of eight hundred feet.

"Guess we'd best descend at once," said Captain Jones.

"Descend--why?" asked Captain Restronguet.

The skipper of the "Pride of Rhodesia" pointed towards the broad Zambesi. Abreast of the junction of the stream in which the "Vorwartz" had taken a vain refuge were three river gunboats.

The huge aerial propellers began to revolve and the "Pride of Rhodesia" gathered way. In view of her skipper's remark Hythe could not at once understand this manoeuvre; but Captain Jones was not a man to waste gas when he could bring his airship to earth by other means.

Circling in ever-descending spirals the huge craft approached within fifty feet of the place where a few minutes before she had been anchored. The bow and stern ropes were thrown down, and assisted by the "Aphrodite's" men those of the crew of the airship who had been left behind dragged the "Pride of Rhodesia" to earth.

Almost as soon as Captain Restronguet, Hythe, and the skipper of the airship had alighted, a motor launch in which were several white-uniformed officers came pelting up stream and brought up alongside the captured submarine.

"We are a trifle too late, I see," exclaimed the senior officer from the gunboats, as salutes were gravely exchanged.

"Third in the field," commented Captain Jones, pointing to his airship. "This is the lucky individual--Captain Restronguet."

"Thought we'd been done in the eye when we saw his submarine out in the stream," said the commodore of the flotilla. "Well, Captain Restronguet, we congratulate you upon having rid the world of a pest."

"The business is not finished yet," said the "Aphrodite's" captain. "We were on the point of following up the rascals."

"Some have escaped, then?"

"All save one, and he's as mad as a hatter."

"Well, it strikes me we are not required here," continued the commodore. "But before we return we would very much like to look over both submarines."

"With pleasure," assented Captain Restronguet. "Unfortunately I cannot stay to have the honour of showing you round, as we wish to overhaul Karl von Harburg and company and be back before night. I'll have a signal sent to my chief officer, Mr. Devoran, and he will act as my deputy."

"Has the news of the capture been sent home?"

Captain Restronguet consulted his watch.

"I believe I am right in assuming that already the newsboys are selling special editions in the streets of London."

"Smart work!" ejaculated the commodore admiringly.

"Fairly," admitted the captain of the "Aphrodite" modestly. "The moment our flag was hoisted on the 'Vorwartz' the news was signalled to the top of the hill. Two of my men are stationed there. They in turn signalled on to my chief officer, who by wireless communicated direct with my London agent. He, I feel certain, lost no time in giving the news to the proper authorities; but making due allowance for slight delays I think my assumption is correct."

"What do you propose doing with the 'Vorwartz,' may I ask?"

"Tow her off as soon as possible and take her down the river. I hope before night to get into wireless communication with the officer commanding H.M.S. 'Pique,' and hand the prize over to him. He can then tow her to Cape Town and there the necessary transactions can be effected. But I must be going. If you will excuse us we will bid you good-day. Perhaps we may meet again in the near future."

Upon re-embarking Captain Jones gave the order for half speed ahead, and the "Pride of Rhodesia," at a modest twenty-five miles an hour, flew over the course of the tributary at a height of less than five hundred feet.

Glasses were brought to bear upon the country beneath them, and every rock and shoal in the river was thus carefully examined. The "Vorwartz" had almost reached the limit for navigation, for at less than a mile above the spot where she had stranded the river shallowed considerably and was interrupted by a series of cataracts. In one of these Hythe spotted a brass-bound box wedged in between two rocks, and by the identification letters on its side Captain Restronguet knew that it was one from a liner's strong-room.

"They've been in difficulties already," he observed. "They've had to jettison some of their booty. Judging by the state of the river, I don't think they can have gone very far."

"There's a dense forest ahead," announced Captain Jones. "That makes our task more difficult. If the rascals have taken it into their heads to make a way through the trees, the thick foliage will screen them from view. However, I'll keep up-stream for some distance yet. Perhaps they haven't the sense of caution to destroy their boat or haul it up out of sight. However, we will see."

"No chance of a boat getting over that," exclaimed the sub, as after a short interval the airship came in view of a waterfall quite forty feet in height and extending from bank to bank. As the "Pride of Rhodesia" drew nearer the noise of the falling water almost outvoiced the purr of the airship's motors. One glance was sufficient to show that nothing afloat would be able to surmount that formidable barrier.

"There's their boat," bawled Captain Jones, into the ear of his successful rival.

He was right. Lying half-way up the steep bank, and only partially screened by the foliage, was a craft of native construction. Two or three paddles, a length of rope and a piece of canvas lay within it, while a jagged hole close to the water-line showed that the boat had come to grief against one of the sharp rocks with which the bed of the river abounded.

"See any tracks?" asked Captain Restronguet.

Hythe, to whom the question was addressed, was minutely studying the ground through a powerful pair of binoculars.

"Not much doubt about it, sir," he replied. "There's a well-defined track leading in a south-easterly direction. I can follow it as far as those trees."

"We'll take the craft up a bit and follow the supposed direction," said Captain Jones. "Ten to one there'll be some sort of a clearing further on. Tilt the forward planes, McPherson. That's enough; keep her as she is and carry on."

For nearly two miles the "Pride of Rhodesia" flew steadily over the tree-tops. So dense was the foliage that for the whole of that distance no sign of the ground was visible.

"Are you prepared to have a bullet through the envelope of the airship?" asked Captain Restronguet.

"No, I'm not," replied Jones bluntly. "Why?"

"We offer a tempting mark. If any of those rogues spot us and open fire----"

"There they are!" exclaimed Hythe.

CHAPTER XXXII.

THE FATE OF VON HARBURG.

The sub pointed to a glade in the forest slightly to the north of the course the "Pride of Rhodesia" was following. Here the ground rose gradually, and save for a few prickly pear-trees was destitute of verdure. Four roughly-constructed tents made from ships' sails had been erected, with a breast-work of boxes surrounding, except for a narrow opening that gave access to the camp. Seven or eight men, regardless of the blazing sun, were lying down or sitting with their backs propped up against the boxes. No attempt had apparently been made to post sentries or to take any steps against a possible surprise, although every man had either a rifle or a revolver close to hand.

"Wonder they haven't heard our motors," remarked Captain Jones, as he ordered the engines to be stopped and the quick-firers to be manned. "They must be sound asleep. I vote we cover them pretty tightly, fire a blank shot and summon them to surrender at discretion."

"They'll fight; they know that as prisoners they'll have a halter round their necks," said Captain Restronguet. "But where are the others? There were several more of the rascals."

"How many, do you think?"

"Not less than thirty all told."

"Well, here goes," ejaculated the "Pride of Rhodesia's" Captain. "Fire a blank from the for'ard starboard quick-firer, Evans. That ought to give them a shake up."

The forest re-echoed to the sharp detonation of the gun, but not a man of von Harburg's party stirred. From the trees myriads of birds, alarmed by the report, rose and flew terrified away, uttering harsh and discordant cries. Then a strange silence brooded over the solitary camp.

Captain Restronguet and Hythe exchanged glances. The look was significant. Captain Jones whistled softly.

"There's murderous work down there," he remarked.

"Sure, sorr, they are as dead as door-nails," exclaimed O'Shaunessey. "Faith, I can see it is a bash over the head as that man has. 'Twould take more than a rale Irish shillelah to do that."

"We must investigate," said Captain Restronguet.

"Don't fancy it somehow," objected Captain Jones.

"All the same it is desirable," continued the "Aphrodite's" owner. "If von Harburg is not down there our quest is not yet at an end. Personally I do not like the business, but how can we report the death of the modern pirate unless we know definitely that such is the case?"

"Very well," agreed Jones. "I'll land you. I'll remain here, for if there are any survivors of the gang and they show fight I can render you much more assistance than if I were down there."

Accordingly the airship was brought close to the ground and Captain Restronguet, Hythe, O'Shaunessey, and Carnon descended the wire rope ladder. Revolver in hand they advanced towards the silent camp. As they approached evidences of what had occurred were not wanting. The canvas tents were shot through and through, the packing cases were riddled and splintered. Every man lying within the wooden breastwork was stone-dead, only one of them being killed otherwise than by a bullet.

Cautiously picking his way Captain Restronguet opened the flap of one of the tents. He paused to allow his eyes to get accustomed to the gloom, then turned and signed to Hythe to enter.

Lying across an empty box was a short, heavily-built man, whose long matted hair and unkempt beard well-nigh concealed his features. A partially discharged revolver lay by his side, his left hand still grasped a flask of spirits. He was stone-dead.

"Karl von Harburg," whispered Captain Restronguet. "My debt in that direction is paid, though I'm glad that he did not die by my hand. He has altered somewhat since last I saw him, but we ought to be able to find conclusive means of identification."

Bending over his dead rival the captain drew a watch from von Harburg's pocket. It was a gold hunter. Within the case was an inscription in German: "To Karl von Harburg from his friend, Ludwig von Thale--September, 1913."

"We'll take this," continued Captain Restronguet. "He was very fond of showing it to people. Ludwig von Thale was a high court official whom von Harburg sold very neatly. But we've seen enough here. Let us get some fresh air."

Further examination showed that most of the boxes had contained gold. By strenuous exertions the crew of the "Vorwartz" had succeeded in dragging a portion thus far. Then they quarrelled amongst themselves. A desperate fight ensued, and of the thirty men only one survived, and he was a raving lunatic. Of the others twelve were found within the camp, the remainder having continued their fight to the death in the neighbouring wood, for there O'Shaunessey and Carnon discovered their bodies, some of them literally grasping their former comrades' throats.

"What's to be done with them, sir?" asked Carnon, pointing to the gold ingots.

"Leave them," replied Captain Restronguet shortly. Then in a lower tone he added, "They are veritably the price of blood. Let them stay. Perhaps someone will find them who will have more need of riches than either you or I will, Carnon. My life-work is practically done now, Mr. Hythe, so let's get back to England as quickly as we can."

"To England!" ejaculated the sub. "I thought you had----"

"Mr. Hythe, remember I am still an Englishman. It is now my intention to settle down in my native Cornwall. I have now more than enough to keep me in ease. My comrades who stood by me so faithfully in times of peril and misfortune, will likewise be amply provided for."

"And the 'Aphrodite,' sir?"

Captain Restronguet's brow clouded.

"I know what you mean, Mr. Hythe," he exclaimed. "No, I mean to keep my vow. I swore I would never hand her over to the Admiralty, and I must keep my word. In due course, Mr. Hythe, I will let you know my intentions; but do not seek to swerve me from my decision. It will be useless to attempt to do so."

Without another word Captain Restronguet turned and strode swiftly towards the airship's ladder. His companions followed. All save the sub put down their leader's taciturn manner to the reaction of the excitement caused by the dramatic termination of his quest. But they were mistaken.

"All accounted for," commented Captain Jones. "Well, that's a blessing, for we don't want rascals of that sort finding their way into British territory. Let her go, McPherson. Full speed ahead. We've got to look pretty smart if we want to get back before sunset."

But the captain of the "Pride of Rhodesia" was mistaken in his calculations. The outward journey at a retarded speed had taken thrice as long as the airship did to fly back to where the captured "Vorwartz" lay.

"The gunboats haven't gone yet," announced Captain Jones, as the broad Zambezi came in sight once more.

The sub's practised eye saw that the two vessels lying just ahead of the "Aphrodite" were not the sternwheelers from Lake Nyassa. He snatched up his binoculars and brought them to bear upon the strange craft.

"Portuguese Government gunboats, by Jove!" he exclaimed. "What's their little game, I wonder?"

"Eh! What's that?" ejaculated Captain Restronguet, overhearing the sub's remark. "Hanging round to see what they can make out of the business, I suppose. Why, there's a crowd of them on shore close to the 'Vorwartz'."

"When Portuguese colonial officials begin buzzing round they're bound to give trouble if you treat them courteously," observed Captain Jones. "I've had experience of them. If you take my advice you'll send them about their business without delay."

"They won't trouble me," replied Captain Restronguet grimly.

"At any rate I'll stand by till they pack," continued the captain of the "Pride of Rhodesia." "We'll descend here. I don't want to bring my craft too close to those gentry."

The airship came to earth at the foot of the little hill on which Kenwyn had been left, and, with the exception of three men who were ordered to remain on guard, the whole of her complement hurried towards the bank of the river.

"Those rogues have been trying to get aboard the prize, sir," exclaimed Polglaze, who had run to meet his captain. "They've given us a stiff job to keep them off. None of us can make head or tail of what that yellow-faced, gold-laced Johnnie was talking about, although he thinks he can speak English."

"Did you come to blows?" asked Captain Restronguet.

"Oh, no, sir; we had to lift one fellow up by his trousers and drop him overboard, but we handled him very gently, although he whipped out a knife."

The Portuguese officer in charge advanced and punctiliously raised his cap, a courtesy that Captain Restronguet returned.

"We haf come to take possession of the pirate, senhor," announced the former.

"To take possession of what?" asked the "Aphrodite's" captain.

"Of pirate ship, over thar."

"You're too late, my friend," announced Captain Restronguet affably.

"Too late? How so?" asked the perplexed Portuguese. "She thar. Me come to take possession in name of Republica."

"You go to blazes!" retorted Captain Restronguet, beginning to lose his temper. "She is my prize."

"By what authority you hold her?" demanded the Portuguese.

"By what authority--we had the permission of the Portuguese Government to ascend the Zambezi."

"Yes; to destroy pirate, not to capture. Since she captured is in Portuguese waters she property of Republica."

Captain Restronguet looked at Captain Jones, and the skipper of the "Pride of Rhodesia" looked at the captain of the "Aphrodite." The absurdity of the Portuguese officer's logic caused them to laugh heartily.

"Tell him we could wipe him off the face of the earth in a brace of shakes," suggested Captain Jones speaking rapidly and in a low tone so that the captain of the gunboat could not understand.

"No, I'll deal with him in quite a different way," was the reply.

"Why you laugh? Me no be laugh at," exclaimed the irate Portuguese. "Me representative of Republica."

"Look here, my friend," said Captain Restronguet. "Do you see that tent pitched on the top of the hill? We've fever amongst us. Had we known you were coming we would have had the yellow flag hoisted to warn you."

The Portuguese officer's face paled under his yellow skin.

"Fever? How say. Madre de Dios!" and he agilely skipped back a couple of paces.

"Yes, very bad case, senhor. Perhaps you would care to see our hospital arrangements?"

But the Portuguese did not care to do so; he precipitately retreated to his boat, followed by his thoroughly scared men, and half an hour later the gunboat was pelting down stream as fast as her crazy engines would drive her.

"Another example of the curse of petty officialdom," commented Captain Restronguet. "No wonder the Portuguese colonies are almost at a standstill. Well, Polglaze, how is the work progressing?"

"We got the whole of the gold on deck, sir," replied the man. "If it hadn't been for those jabbering Dagoes hindering us we would have had the whole lot ashore by now."

"Time to be off," remarked Captain Restronguet. "It will be dark in less than twenty minutes. Leave the stuff there; it won't be touched."

Hastily the "Aphrodite's" men made their way back to the banks of the Zambezi, bringing Kenwyn with them--the second officer was already on the road to recovery, and the spell ashore did him a considerable amount of good.

As soon as the crew regained the "Aphrodite" she was battened down and submerged. The wearied crew sought slumber, but it was long ere Captain Restronguet, Devoran, and Hythe retired to rest, for the first officer had to be told in detail of the momentous events of the day.

Captain Jones did not relinquish his task at that point, for anxious to aid his successful rival to the utmost of his ability he kept the "Pride of Rhodesia" floating over the captured submarine. All night the airship's searchlights played upon the "Vorwartz" and the store of gold lying on the shore, but the precaution, though desirable, was unnecessary.

Early on the following morning all hands assisted in warping the "Vorwartz" into deep water. The bullion and species were then taken on board by means of the "Aphrodite's" whaler, and, bidding the captain and crew of the "Pride of Rhodesia" a hearty farewell, the two submarines commenced the descent of the river.

Two days later the "Aphrodite," with the captured "Vorwartz" in tow, recrossed the dangerous bar. Five miles off-shore the British cruiser "Pique" was awaiting them, and handing the prize over to the care of the latter, Captain Restronguet ordered full speed ahead.

All Cape Town was bubbling over with excitement when the "Aphrodite" dropped anchor in Table Bay. The shipping was gay with bunting, flags were flown from the Government buildings and most of the houses. Bands were playing and people shouting themselves hoarse, while the renowned submarine was literally wedged in between tiers of boats filled with curious and enthusiastic spectators.

The Admiralty had telegraphed to the Commander-in-Chief of the Cape offering Captain Restronguet a commission in the Royal Navy as Inspecting Officer of Submarines; Lloyd's had asked his acceptance of a sword of honour; the Crowned Heads of Europe bestowed decorations with lavish hands, while the President of the United States of America telegraphed his congratulations, and begged Captain Restronguet to be the honoured guest of the greatest Republic on earth.

But the captain of the "Aphrodite" showed no enthusiasm at these honours. Some he could not with courtesy decline, but he strenuously refused to accept the proffered commission. His sole object, he avowed, in calling at Table Bay was to make necessary arrangements with the authorities for the disposal of the "Vorwartz" and the distribution of the prize-money.

"Now, lads," he exclaimed, addressing his faithful crew, "our mission is ended. We are now homeward bound; not to our temporary quarters in Sumatra but to our only home, Old England. I am in a position to state that the individual share of prize-money will be duly paid on our arrival in England, and that every man will be in a state of affluence. I only hope you will be long spared to enjoy it. In less than three weeks, all being well, I hope to land you all at Falmouth."

"Three cheers for Falmouth!" shouted Polglaze.

"An' three cheer for Ould Oireland," added O'Shaunessey. "Faith! I'll take me discharge an' boi the largest farm in all County Wexford."

CHAPTER XXXIII.

HYTHE'S MASTERSTROKE.

Early in the month of November Captain Gregory Pinney, master and owner of the ocean-going tug "Wayfarer," registered at the Port of Falmouth, was the recipient of a telegram transmitted through the Lizard signal station.

"Send vessel to meet submarine 'Aphrodite' 4 miles S.S.E. of Lizard at noon on the 12th inst--Restronguet."

The worthy skipper was obviously perplexed. He rather suspected that it was a bogus message, sent by a rival firm so that their tugs could pick up a remuneration job in the absence of the "Wayfarer." That was his construction of the matter, and his views he communicated to his partner, Captain Hiram Varco.

"Powerful strange," admitted Varco. "Why not wire to the Lizard and ask 'em if it's genuine, and how they picked it up."

Acting on this device Captain Pinney requested Lloyd's Station for further particulars, and received a confirmatory answer with the additional information that the message had been sent from the "Aphrodite" when twenty miles west of Cape Finisterre.

"All the same, it be powerful strange," remarked Varco. "Submarines don't want tugs to give 'em a pluck into port, and Falmouth, too, of all places. Still, if I was you, Gregory Pinney, in a manner o' speakin' I'd take the 'Wayfarer' out. If 'tain't one thing 'tis often another, and chances are you'll pick up something to tow into t'harbour even if 'tain't this wunnerful submarine."

Accordingly Captain Gregory Pinney made necessary arrangements for the "Wayfarer" to proceed to sea early on the morning of the 12th.

Had Captain Pinney not informed his crony of the contents of Captain Restronguet's telegram the momentous news would never have spread abroad, for the skipper of the "Wayfarer" was, for a Cornishman, extremely reticent. Captain Hiram Varco was almost the reverse, and happening to fall in with an enterprising reporter of The Cornish Riviera Express, he waxed eloquent over a friendly glass of double cider.

Next day the London papers published the news, not without comments, for while it was tacitly accepted the message was perfectly genuine, no satisfactory reason could be assigned to Captain Restronguet's motive in requisitioning a tug.

Steps were taken to give the "Aphrodite" and her gallant crew a rousing welcome. Excursion steamers, laid up for the winter, were hurriedly chartered by speculative syndicates and sent round to Falmouth. Long before the fateful Twelfth all the accommodation was booked at a guinea a head. Fishing-boats, risking the Board of Trade regulations, became temporary pleasure craft; luggers, quay-punts, and even frail rowing boats were hired, so that should weather permit, a general exodus of the various craft for Falmouth Harbour would take place--an event to be talked about in years to come by the old salts of the West country. Great Britain in general and Cornwall in particular, meant to show the proper way to welcome home a national, nay, world-wide hero.

*      *      *      *      *

Dawn was just breaking when the "Aphrodite" sighted the powerful white flash-light of the Lizard. The submarine had made short work of the run across the bay and had arrived off the English coast some hours earlier than Captain Restronguet had anticipated.

"I thought better of Captain Pinney," remarked Captain Restronguet to Hythe as the two stood on the deck gazing towards their native land. "Kenwyn tells me that a wireless message came through during the night. The news has leaked out and there's to be a whole crowd of shipping to see us arrive. I think I can promise that they won't be disappointed of a spectacle."

Captain Restronguet and his guest were early on deck. The sea was smooth, the air mild for the time of year, nevertheless they were glad of their great-coats after sweltering under the African sun.

"Will nothing alter your decision, sir?" asked the sub almost pleadingly.

"Nothing, my dear Hythe. A promise with me is a promise, even if made in over-hastiness. I might regret it; but the fact remains that I have sworn never to hand my invention over to the British Government. Consequently I have sent for a Falmouth tug to remove the crew and their personal belongings. This done I mean to open the inlet valves of the 'Aphrodite' and sink her for good and all. At the spot I have indicated the depth is more than forty fathoms. The sea will hold my secret, and from the cliffs about the Lizard I can stand and gaze upon the tomb of my invention."

"But isn't this carrying a one-sided feud too far, sir? Surely my Lords have made ample reparation for a slight for which they were responsible yet perhaps ignorant?"

"Time is a great healer, Mr. Hythe; but the reminiscences of my early struggles with fate cannot be easily erased. But let us not discuss the matter further: it cannot alter my decision in the faintest degree. Ah! good morning, Mr. Devoran. All correct?"

"All correct, sir. We've still plenty of current left to take the 'Aphrodite' another two hundred miles if necessary."

"I don't think we shall require so much as that, Mr. Devoran. Will you please muster all hands aft. Stop the motors, so that the engineers can be present. I wish to say a few words."

As soon as the "Aphrodite" lost way the men came on deck, and formed up just abaft the after conning-tower.

"Men," began Captain Restronguet in stentorian tones, "our voyage is almost accomplished, our great task is completed and little remains to be done as far as your services are concerned. Circumstances compel me to take a drastic step. The 'Aphrodite' must never enter Falmouth Harbour. At noon we will fall in with a tug that most of you, I know, are familiar with--the 'Wayfarer.' I want every man to collect his personal effects and stow them into as small a compass as possible, ready to be transhipped on board the tug. As soon as all hands are clear of the submarine I intend to send her to the bottom."

Dead silence greeted this announcement. The men looked at each other in amazement.

"To sink her for ever, sir?" asked Polglaze, when he found his tongue.

"Certainly," replied Captain Restronguet.

"You are not going down with her, sir?" asked another.

"No," replied Captain Restronguet grimly. "I'm not at all that way inclined. Now, men, you have a couple of hours to make the necessary preparations, so dismiss and make the best of the time."

With that the captain went below and retired to his cabin. Hythe, bitterly disappointed at the failure of his attempt to swerve Captain Restronguet from his purpose, walked for'ard and remained by the fore conning-tower deep in thought.

"Say, Mr. Hythe, what is the cap'n thinking about?" exclaimed a voice, and turning the sub found himself face to face with Jenkins.

"The sun hasn't affected him, eh?" continued the aviator-in-chief to the Sultan of Zanzibar, touching his forehead significantly.

"I don't think so," replied Hythe. "It is, I believe, the outcome of a vow."

"Precious silly vow," remarked Jenkins. "He always was a queer customer when he was upset. Can't you prevent him?"

"I've tried," said the sub.

"Fair means or foul, I'd have another shot at it if I were you. I'll back you up."

The man's words stirred the sub to serious thought. A struggle between his sense of gratitude to this man who had so improved his knowledge of submarine work, and his duty to his king and country waged a fierce battle. The "Aphrodite" was Captain Restronguet's by right. He was wilfully abandoning it--an act that was also within his rights. On the other hand the possession of the "Aphrodite" by the British Navy would mean an undisputed supremacy in submarine welfare. This wonderful vessel would be the means of thwarting any projected invasion by a hostile state, whether by air or by sea.

"In matters of this description personal considerations must be put aside in favour of one's obligations to one's country," decided the sub, and straightway he sought out his faithful henchman, O'Shaunessey.

"Sure, sorr, I think we wud manage ut, be dad," was the Irishman's comment when Hythe unfolded his plan.

At half-past eleven the van of the flotilla from Falmouth came abreast of the "Aphrodite"--two large steamers packed with people who cheered and shouted while strident brass bands added a deafening welcome.

Circling, these vessels followed on either quarter of the submarine--so close that Captain Restronguet had to shout to request them to keep a more respectful distance. Abreast of the Lizard the main portion of the waterborne spectators was encountered, till surrounded by nearly a hundred craft of all sizes and rigs the "Aphrodite" forged slowly ahead towards a squat high-sided vessel which Captain Restronguet recognized as the "Wayfarer."

Finding the attentions of his escort too pressing the "Aphrodite" hoisted a red burgee from a pole set up on her fore conning-tower--a hint that explosives were about to be transhipped and that there was a certain element of danger in the undertaking. With that the obstructing vessels backed away a few yards, forming a complete circle in the almost motionless sea around the "Wayfarer" and the craft that had engaged her.

"D'ye want me to pass you a hawser out astern?" bawled the master of the tug.

"No, thank you, Gregory Pinney," replied Captain Restronguet. "Lay alongside, will you?"

"An' who may you be?" demanded the skipper, somewhat astonished to find himself hailed by name. "Mussy me! Why, it is Mr. Tretheway."

"Good shot, Pinney! How's things at home?"

"Pretty middlin', thanks, Mr. Tretheway. But what might I be wanted for? Where's Captain Restronguet?"

The captain laughed.

"Thought you'd have cottoned to it before now, Pinney. I am Captain Restronguet, but only for a few moments more. After that I am plain Hugh Tretheway--and I do not feel altogether sorry. But get your masthead derrick swung out: we've plenty of gear for you to take."

For nearly an hour the task of unloading the "Aphrodite" continued, for the personal effects of the officers and men reached considerable dimensions. It seemed really marvellous where the stuff had been stored within the limited accommodation of the submarine.

"That's all, sir," announced Devoran.

"Very good. Now, men, on board the tug."

One by one the men passed over the narrow gangway between the two vessels. As the first was about to leave the "Aphrodite's" deck he drew himself up and gravely saluted the green and white flag still flying at the stern of the submarine. His example was followed by the others, while Captain Restronguet, for the last time in his official capacity, promptly returned the salute--a final tribute of devotion to a brave and gallant leader.

After the men the officers boarded the "Wayfarer," till Captain Restronguet alone remained on the deck of the "Aphrodite." The submarine was battened down with the exception of the main hatch close to which the captain stood with his hand resting on a lever actuating the sea-cocks.

Then with a swift deliberate motion he thrust the metal rod hard down, saluted his flag, and walked slowly up the gangway.

"Cast off there, Captain Pinney, unless you want to be dragged down," he exclaimed. "The 'Aphrodite's' sinking."

The men of the tug hastened to unfasten the securing hawsers. The for'ard one was soon cast off, but by the after one three men purposely impeded the efforts of the "Wayfarer's" deckhands. The three men were Hythe, O'Shaunessey, and Jenkins.

The tug's engine-room telegraph bell clanged, the water churned under her squat counter, and, as she slowly forged ahead, the strain on the after-rope swung her stern close to the "Aphrodite's" deck.

Simultaneously Hythe and O'Shaunessey vaulted over the low bulwarks and leapt upon the submarine, Jenkins making a good third. Before Captain Restronguet and his companions could grasp the situation the three men gained the open hatch. They were not a second too soon, for the water was rising over the deck and lapping against the coamings of the hatchway.

With a clang the metal covering fell. The "Aphrodite" was heremetically sealed, with her captors safe within.

"Start the motors, Jenkins," exclaimed the sub triumphantly. "O'Shaunessey, bring that lever hard down."

Seven fathoms deep the submarine sank, then as her motors began to purr rhymically, Hythe pointed her head due east.

*      *      *      *      *

Early next morning, before it was light, Sub-Lieutenant Arnold Hythe dexterously brought the submarine into Portsmouth Harbour, and, confident that the importance of his errand would justify the unearthly visit, boldly called upon the Commander-in-Chief.

Forgetting his dignity in his anxiety to hear what had actually occurred to the "Aphrodite"--for, as usual, vague rumours had been floating round--Sir Peter Garboard made his appearance clad in a dressing-gown.

"You're back again, Mr. Hythe? Tell me, is it right that Captain Restronguet has scuttled the 'Aphrodite'?"

"Hardly that, sir; she is at this moment alongside the North Railway jetty. You see, sir, I stole her."

"You stole her? Explain yourself."

Hythe explained, pointing out the difficulty in which he had been placed in his desire to do his duty.

"Rest easy on that score, Mr. Hythe," said the Admiral good-humouredly. "From a strictly legal point of view your action is justifiable. The submarine was a derelict after the captain had abandoned her, and as a naval officer you did right by taking possession of her. But have you had breakfast?"

The sub was perforce obliged to partake of a repast with his superior officer, who kept him busily employed the whole while in answering questions. Presently the Admiral's secretary entered.

"Ah, good morning, Holmes; anything startling?"

"No, sir. Captain Restronguet has apparently vanished into thin air. All inquiries at Falmouth have proved fruitless. But I expected to find Mr. Hythe here."

"How so?"

"Because there is a telegram sent to him, care of the Commander-in-Chief, sir," replied the secretary.

The sub took the proffered envelope and opened it, with a muttered apology to his superior officer.

"That's all right!" he exclaimed with a sigh of relief. "Read this, sir."

Sir Peter read it aloud:--

"Hythe, care of C.-in-C., Portsmouth. Thoroughly glad you acted as you did. Aphrodite is the nation's. Still I have kept my vow.--Tretheway."

"Tretheway, who is he, Mr. Hythe?"

"Tretheway, sir, was Captain John Restronguet, until yesterday commander of what is now the latest and most powerful acquisition to His Majesty's Navy--the 'Aphrodite.'"

THE END.

WILLIAM BRENDON AND SON, LTD., PLYMOUTH, ENGLAND

[The end of The Rival Submarines by Westerman, Percy Francis]