Produced by Al Haines

[Illustration: Cover art]

[Frontispiece: "THE BLACK CROSS FLAG WAS HAULED DOWN,
  AND REHOISTED UNDER THE WHITE ENSIGN"]

The Submarine Hunters

  A Story of Naval Patrol
  Work in the Great War

BY

PERCY F. WESTERMAN

  Author of

  "Rounding Up the Raider"
  "The Dispatch-Riders"
  "The Fight for Constantinople"
  &c. &c.

_Illustrated by E. S. Hodgson_

BLACKIE AND SON LIMITED

LONDON GLASGOW AND BOMBAY

1918

Contents

   CHAP.

      I.  THE MYSTERIOUS MEETING ON ST. MENA'S ISLAND
     II.  THE TABLES TURNED
    III.  KIDNAPPED
     IV.  THE AWAKENING
      V.  ABOARD U75
     VI.  THE TRAMP
    VII.  ON THE BED OF THE SEA
   VIII.  BALKED BY A SEA-PLANE
     IX.  THE LANDING AT PORT TREHERNE
      X.  A TREACHEROUS PLOT
     XI.  PREPARATIONS
    XII.  THE WHITE FLAG--AND AFTERWARDS
   XIII.  THE ARM OF THE LAW
    XIV.  A FRUITLESS QUEST
     XV.  THE ADMIRAL WORKS THE ORACLE
    XVI.  H.M.S. "CAPELLA"
   XVII.  A DOUBLE BAG
  XVIII.  THE SMOKE-SIGNALS
    XIX.  THAT FRIDAY NIGHT
     XX.  TO THE RESCUE
    XXI.  ADRIFT IN THE CHANNEL
   XXII.  AN UNEXPECTED CAPTURE
  XXIII.  MINED
   XXIV.  "SHRAP"
    XXV.  OFF THE BELGIAN COAST
   XXVI.  DISABLED IN MID-AIR
  XXVII.  NOT ON PAROLE
 XXVIII.  ALMOST RECAPTURED
   XXIX.  BOUND FOR THE BALTIC
    XXX.  THE AFFAIR OFF KIEL

Illustrations

"THE BLACK CROSS FLAG WAS HAULED DOWN AND
  RE-HOISTED UNDER THE WHITE ENSIGN" . . . . . . . . . _Frontispiece_

THE INTERVIEW WITH THE GERMAN CAPTAIN (missing from book)

"'D'YE KEN YON?' ASKED THE BRITISH SKIPPER, AS HE
  EYED THE PODGY GERMAN LEUTNANT WITH CONTEMPT"

"THE 'TREMENDOUS' WAS HEADING STRAIGHT FOR THE DOOMED SUBMARINE"

THE SINKING OF THE "ORONTABELLA" (missing from book)

"THE WORK OF DEMOLITION WAS ACCOMPLISHED"

THE SUBMARINE HUNTERS

CHAPTER I

The Mysterious Meeting on St. Mena's Island

"We've made a proper mess of things this time!" ejaculated Ross
Trefusis--"or rather I have."

"It can't be helped," rejoined his chum, Vernon Haye.  "We've done our
level best to get her off.  How long is it before the tide floats her?"

"A matter of seven or eight hours, worse luck.  You see, it was only
half ebb when we landed."

Ross bent down to remove a streak of bluish-grey mud from his ankle.

"I wish we'd taken the rowing-boat instead of this heavy old tub," he
continued.  "We'll be pretty peckish before we get back to the Hall,
and dinner's at seven-thirty."

Vernon laughed.

"It wouldn't be the first time I've had to go without grub," he
remarked.  "If you don't mind, I don't."

"Then it's no use standing here," said Ross.  "Let's get on our shoes
and go for a stroll."

Vernon Haye was a broad-shouldered lad of fifteen, with clear-cut
features and dark hair.  His companion was of about the same age, but a
good two inches taller.  His complexion was florid, his hair of an
auburn tint that narrowly escaped coming within the category of red or
ginger.  His features were full and rounded.  In short, he was a
typical Cornish youth.

Ross's father, Admiral Paul Trefusis, lived at Killigwent Hall, a
large, rambling, sixteenth-century house, standing within a mile of the
sea on the North Cornish coast.

Both lads went to the same public school, but owing to the fact that
Vernon's father, Captain Haye, was on active service with the Grand
Fleet, young Haye was spending the summer holidays with his chum at
Killigwent Hall.

That afternoon the lads had taken a small sailing-boat and had made for
St. Mena's Island, a small rocky piece of land lying about a mile off
shore, and nearly five miles from Killigwent Cove.  The island was
roughly three-quarters of a mile in length, and four hundred yards wide
in the broadest part.  The north and west sides were precipitous, but
on the side nearest to the mainland the ground sloped gradually, and
was indented by several narrow tidal coves.

The glamour of romance lay thickly around that rocky pile.  Centuries
ago it was the abode of a hermit, who, amongst his various self-imposed
tasks, had built a chapel on the summit, from the tower of which a wood
fire was kindled nightly to warn mariners of the treacherous reefs in
the vicinity of the island.

In course of time, St. Mena's Island became the haunt of wreckers and
smugglers.  The chapel, in spite of its massive construction, fell a
victim to the ravages of wind and weather, but still served as a
convenient shelter for the lawless Cornishmen who profited by the
misfortunes of honest seamen.  Immune from interference, by reason of
the superstitious awe in which the island was held by the country-folk,
the smugglers and wreckers thrived exceedingly until late in the
eighteenth century, when stern measures were taken to suppress their
misdeeds.  From that time St. Mena's Island was deserted, except for
the casual visits of tourists and summer visitors from the neighbouring
towns of Padstow and Newquay, and countless numbers of sea-birds that
take up their abode in crannies in the almost inaccessible cliffs.

Ross Trefusis was right in taking the blame of their misfortunes upon
himself.  He knew better, but, neglecting to take ordinary precautions,
he had allowed the boat to be left high and dry by the falling tide.
Upon returning to the cove the lads had found the heavy craft lying on
its bilge in the stiff bluish clay, with a ridge of jagged rocks
cutting her off from the sea.

"Perhaps," suggested Vernon, "some other boat will put off to the
island, and we can get them to put us ashore."

"Hardly likely," was the reply.  "Anyway, we'll keep a look-out.  Which
would you prefer to do--explore the Smugglers' Cave and Dead Man's
Cave, or climb up to the ruins?"

"The ruins," decided young Haye eagerly.  "I like fooling about old
ruins, and I've already seen the caves.  Besides, we can see if there
are any boats about.  It's almost like being shipwrecked on a desert
island."

"Hard lines if we were," commented Ross.  "Suppose we take an inventory
of our possessions?  Let the see: one pocket-knife, a silver watch that
has refused duty, a notebook and pencil, and five shillings and three
halfpence.  What have you to add to the common stock?"

"A knife, a pocket compass, my watch--which does go; it's now
five-and-twenty to four--and sixteen shillings and eightpence in paper
money and hard coin."

"Not a morsel of grub between the pair of us, then," declared Ross.
"Outlook beastly unpromising.  Faced with starvation unless we make up
our minds to knock over some gulls.  They are horribly fishy to eat, I
believe, and we've nothing to make a fire."

"It makes you pine for the flesh-pots of Kllligwent Hall, old man,"
exclaimed Vernon laughingly.  "Never mind, let's make a move.  I vote
we get rid of these sweaters.  It is frightfully hot."

Stripping off their woollen garments, and placing them for safety under
a gorse bush, the two lads made their way up the steep ascent to the
ruins, till, hot and well-nigh breathless in spite of being "in
training", they reached the summit of the island.

"What a jolly view!" exclaimed Vernon, turning and taking in the
panorama of rocky coast-line, an expanse of jagged, frowning, brownish
cliffs topped by the brilliant green of the Cornish moorland.

"Not bad," agreed Ross complaisantly, for the view was no stranger to
him.  "See that cliff shaped like the head and shoulders of a bearded
man?  That's Hidden Money Cove that I was speaking to you about last
night.  We'll go there next week, all being well.  You see, there's not
a sail in sight, so our chances of getting back to dinner are very
remote.  What's more, unless I'm very much mistaken, there's a
rain-storm coming.  See that dark cloud working up against the wind?"

"Yes," assented Haye.  "What of it?  A little rain won't hurt."

"It's the after effect," said Ross.  "It's quite possible it may blow
hard before night, in which case we're done for.  I've known it
impossible to approach Killigwent Cove for a week at a time."

Vernon whistled.

"Sounds lively," he remarked.

"Of course that is in the winter," his chum hastened to remind him.
"These summer gales don't last very long, but we'll be feeling precious
hungry by the time we get home, I guess."

"Look here," said Vernon after a while.  "I vote we get those sweaters.
We don't want to be soaked."

"Very well," assented Ross.  "But there's no great hurry."

Having retrieved the sweaters, the chums leisurely retraced their way
to the ruins.  For half an hour or more they wandered around the
remains, descending into the dark crypt, and running considerable risk
in climbing to the summit of the tower.  Since the spiral stone steps
had vanished long ago, the only means of getting to the top was by
climbing the gnarled stem of the ivy which grew profusely on the face
of the building.  The tower was roofless, a low, partly demolished
parapet encircling it on three sides, while a couple of weather-worn
oak-beams supporting a few planks formed a kind of platform where the
roof formerly existed.

"Think it's safe?" asked Vernon anxiously, as his chum, having got
astride the parapet, was about to lower himself upon the decrepit
woodwork.

"I've done it scores of times," said Ross confidently.  "That's right,
I'll guide your foot.  Now let go."

"By Jove!" suddenly exclaimed Haye; "there's a fellow coming towards
the ruin.  How on earth did he get here?"

"Goodness only knows," said Trefusis inconsequently.  "He may have
landed in Main Beach Cove.  Anyhow, he's at perfect liberty to do so.
I suppose he's interested in ruins."

"Let's drop a bit of stone and give him a shock when he gets here,"
suggested Vernon.  "We'll apologize afterwards.  Ten to one he'll give
us a passage back."

"I'm not so keen on dropping chunks of stone," objected Ross.  "I vote
we lie low for a bit at any rate, and see what he's up to."

"Why, do you think he's a spy?" asked his companion.  Trefusis grunted
scoffingly.

"Spy?" he repeated.  "What object would a spy have on St. Mena's
Island?  This part of Cornwall is well outside the military area.
There's nothing in the fortification line for miles.  No, it's not
that.  But _cave_, here he comes."

The lads crouched behind the crumbling parapet, and by means of
conveniently placed gaps in the masonry watched the stranger's approach.

There was nothing about the man's appearance to suggest that he was
anything but an ordinary holiday-maker.  He was slightly above average
height, rather heavily built, and inclined to flabbiness.  His
complexion was undoubtedly florid, although his face and hands were
tanned a deep brown.

He was dressed in a light-grey lounge suit, with a straw hat and brown
shoes, while in his right hand he carried a thick Malacca cane.

The exertion of climbing up the hill on which the ruined chapel stood
apparently told upon him, for he was considerably out of breath when he
passed under the ivy-clad arch.  Here he stopped to wipe his face with
a handkerchief, and while doing so dropped his cane.

It fell upon the stones with a dull thud.

At the same time the stranger gave vent to an exclamation that
certainly was not English.

The lads exchanged glances.  Here was the beginning of a mystery.  The
heaviest Malacca cane would not have made that dull metallic sound in
falling, while it was evident by the careful examination the stranger
made of the retrieved article that he was more than considerate for its
appearance.

The man made no attempt to explore the ruins.  The weather-worn fane
had no attractions for him.  It was apparently only a rendezvous, as
far as he was concerned, for at frequent intervals he would walk
stealthily through the archway, and look attentively down the hill
leading to the coves on the side facing the mainland.

It had now begun to rain--big drops that were the precursors of a heavy
shower.  The lads, in their exposed position on the tower, paid scant
heed.  Their interest and attention were centred upon the anxiously
awaiting stranger fifty feet beneath them.

Presently Ross happened to glance towards the stretch of water that
separated St. Mena's Island from the mainland.  A boat was approaching.
Already it was more than half-way across.  It was a rowing-boat,
containing only one person.  What object would anyone have in rowing
across on a wet afternoon like this? wondered the lad.

Just then the stranger began rubbing his hands with ill-concealed
satisfaction.  Although he had been frequently on the look-out, he had
evidently only just caught sight of the approaching boat.

The lads watched the little craft till it was hidden by the intervening
high ground, but already Ross felt certain that it was making for Main
Beach Cove.

There were three landing-places on St. Mena's Island--Half Tide Cove,
where the lads had left their stranded boat; Main Beach Cove, a little
to the north-east; and Deadman's Cove, farther away.  Of these, only
Main Beach was available between one hour on either side of low water.
The fact that the boat was making for it, and had already successfully
skirted the submerged reef lying off it, proved that its occupant had
local knowledge.

Some considerable time elapsed between the temporary disappearance of
the boat and the appearance of the new-comer; but at length he came
into view, walking rapidly up the steep incline without showing
anything of the physical strain that the first stranger had betrayed.

Suddenly Ross Trefusis recognized the man.  He almost felt inclined to
laugh at his suspicions.  It was Dr. Ramblethorne, the medical
practitioner at St. Bedal--a town of considerable importance about
seven miles from Killigwent Hall.  The doctor was a frequent guest of
Admiral Trefusis, and was generally considered a good, all-round
sportsman.  He was about thirty years of age, over six feet in height,
of sinewy frame and of great muscular power.  He was the wildest
motorist in that part of Cornwall, as the endorsements on his driver's
licence testified.  A keen golfer, good shot, and fisherman, he was
also a botanist; and that, perhaps, thought Ross, might account for his
presence on St. Mena's Island, although it was difficult to reconcile
the fact that Ramblethorne had an appointment with a stranger at this
desolate spot.  If a joint botanic expedition had been fixed up, why
had not the two men met on the mainland?

The unknown made no attempt to advance to meet the doctor.  Instead, he
remained within the ruins until Ramblethorne entered.

Their greeting was a surprise even to the lads, for the doctor, holding
out his hand, exclaimed in German:

"Well met, von Ruhle!  Let us hope that your arrangements will prove
satisfactory."

CHAPTER II

The Tables Turned

Both Ross Trefusis and Vernon Haye understood and could speak German.
Ross was especially good in his knowledge of the language of the modern
Hun, for in his early youth he had been inflicted with a German
governess.  Since German is one of the subjects for Sandhurst--for
which both lads were preparing--their knowledge had been considerably
improved under the cast-iron rule of a native professor.

"Eminently satisfactory," replied von Ruhle.  "We will go into details
later.  You had no difficulty in coming here, I hope?"

"None whatever."

"No suspicions?" asked von Ruhle anxiously.

Ramblethorne smiled.

"My dear von Ruhle," he replied.  "A medical practitioner is above
suspicion.  He is free to go anywhere at any hour of the day or night
without question.  No man would suspect----"

"You are clever, von Hauptwald----"

"Ssh!" interrupted the doctor.  "Call me Ramblethorne, if you please.
Of course there is no danger here, but at other times and in other
places you might incautiously give the show away.  You had a good
passage?"

"Excellent," replied von Ruhle.  "I am getting well-known to the
strafed English custom-house officers at Queenboro' and Harwich.  They
recognize me by my stick, I believe, but they little know that it is a
new one every time.  What do you think of this?  I have brought it as a
specimen for you to see.  Just fancy! every time I cross to Holland
twenty kilogrammes of good copper are on their way to the Fatherland.
By this time Herr Stabb of Essen is well acquainted with my Malacca
canes."

"A good weight to carry about," remarked Ramblethorne, wielding the
disguised bar of copper.  "I wonder you troubled."

"Mein Gott!  I could not leave it," declared von Ruhle.  "Someone might
take a fancy to it, and then the secret would be out.  But tell me:
have you succeeded in getting that commission you spoke of?"

"I am still living in hopes," replied Ramblethorne.  "Of course I could
have obtained a post of temporary surgeon in the British Navy, but it
wasn't good enough.  It's no fun running the risk of being torpedoed by
our own Submarines.  The English Army offers a wider scope.  Believe
me, I am worth more than a division to the Emperor.  I'll get a
commission, never you fear, for I have heaps of influence.  Then, of
course, I will do my utmost to fight against a terrible epidemic that
will mysteriously break out amongst the troops."

Ramblethorne, otherwise von Hauptwald, threw back his shoulders and
laughed uproariously.

"Careful!" hissed his companion.  "You will be heard over the whole
island."

"What matters?  There is not another soul in sight besides ourselves.
How much petrol have you?"

"Fifty two-gallon tins.  I expect some more by boat to-morrow.  It's
safely stored in a cave on the side of the creek.  It is a nuisance it
is raining.  I do not fancy a night's work in weather like this.
Himmel, what's that?"

Accidentally Vernon's foot had dislodged a small piece of stone.

"Nerves, my dear von Ruhle," said Ramblethorne, with his usual
good-natured smile.  "A bit of masonry has fallen from the tower.  See,
the floor is covered with similar pieces."

"If anyone should be up there----" suggested von Ruhle, pointing to the
top of the tower.

The lads could feel their hearts thumping against their ribs.  Through
a small crack in the planking they could see the eyes of the two
Germans directed upwards.

"Impossible; there are no steps," declared Ramblethorne.  "Besides,
what object would anyone have in ascending a tower on a day like this?
I fully appreciate the danger of being overheard, of course.  We've
said enough to find ourselves faced by a firing-party in the Tower of
London, my friend."

"Don't!" expostulated von Ruhle, closing his eyes as if to shut out the
unpleasant mental vision.  Then: "You have the signalling apparatus, I
hope?"

"Trust me for that, von Ruhle," replied his companion, tapping his
breast-pocket.  "All we have to do is to wait until yonder lighthouse
exposes its light.  Really the ways of these English pass
understanding.  They rigorously forbid the showing of lights in private
houses on shore, imagining that our agents would be so foolish as to
start blinking with a lamp; yet they allow these lighthouses to work as
usual, and obligingly enable us to communicate to our hearts' content."

Von Hauptwald was not far wrong in his remarks, for the instrument he
had enabled him to flash a message to a confederate without having to
be in possession of a lamp.  The flash was obtained from any distant
and visible light by means of a complicated system of mirrors.  The
reflected rays could then be projected in any desired direction so as
to be quite invisible except on a certain bearing.  It was one of the
carefully-thought-out plans adopted by the German Government to permit
its spies to communicate with their submarines without running any
great risk of detection.

"It's two hours to sunset," remarked the doctor; "three before we
commence operations.  I would suggest that we adjourn to the cave and
partake of refreshment.  You see, I have not omitted to make suitable
provision."

"Very good!" agreed von Ruhle; "but I only wish I had a waterproof.
The rain is most annoying."

Arm-in-arm the two men left the building, and presently disappeared
from view behind a slight rise in the ground.

"I say!" exclaimed Ross; "we've tumbled on something this time.  Fancy
Ramblethorne a rotten German spy.  I always thought he was a rattling
good chap."

"Evidently he isn't," rejoined Vernon.  "But the point is: what do you
propose to do?  It's beastly wet here."

"It is, now I come to think of it," agreed his chum.  "The fact is,
that until you mentioned it I was hardly aware that it was raining.
We'll discuss this knotty point."

"I vote we make tracks for the boat," suggested Haye.  "The tide must
be rising by this time.  We can then slip off and raise the alarm."

Ross shook his head.

"No go," he decided.  "We might get nabbed ourselves.  Besides, who
would be able to lay these chaps by the heels?  There's only that
motor-boat chap at Penydwick Cove, and he's precious little use.  There
are no soldiers nearer than at St. Bedal.  I propose we hang on here.
There's a snug, sheltered hole in these ruins, just big enough for us
to lie hidden.  Then we stand a good chance of hearing more of the
conversation between those beggars."

"Three hours more, remember."

"Yes, I know.  In the meanwhile we might slip down to Main Beach Cove.
There's plenty of cover amongst the rocks."

"What for?" asked Vernon.

"To see what these fellows are up to.  I'm rather anxious to renew my
slight acquaintance with friend Copperstick.  By Jove, what a cute move
to get contraband metal into Germany!"

"Not much at a time.  It shows how hard up the Germans must be for
copper when it pays a fellow to carry over about half a hundredweight
at a time."

"Well, let's get a move on," said Ross.  "Be careful how you descend.
The ivy will be fairly slippery with the wet."

Cautiously the two lads descended, reaching the ground without mishap.

"Our sweaters!" exclaimed Vernon.

"Dash it all!  Yes," agreed his companion.  "I had forgotten all about
them."

The sweaters, carefully rolled up, had been placed for security in one
corner of the chapel.  Unless anyone actually came close to the spot,
they were hidden from sight.

"Neither of those fellows stood about here, I think," remarked Ross as
the chums retrieved and donned the additional clothing.  "It's jolly
lucky, or they would have smelt a rat."

Trefusis and his companion went out into the rain, walking rapidly
towards a slight mound capped by a few irregularly shaped stones.  It
was behind this rise of ground that the two spies had gone.  Up to this
point, Ross argued, there was little need for caution; beyond, it would
be necessary to keep well under cover until they reached Main Beach.

"'Ware the skyline," cautioned Ross as the chums approached the hillock.

"Ay; 'ware the skyline," said a deep voice mockingly, "It's bad
strategy."

Turning, the lads made the disconcerting discovery that Ramblethorne
and von Ruhle were within five yards of their would-be trackers.

Ross realized that he and his chum had been badly outmanoeuvred.
Evidently the Germans suspected that they had been overheard, and
ostentatiously leaving the ruins for Main Beach Cove, they had made a
detour from the hillock, and had waited until Ross and Vernon had
emerged from the chapel.  Then, taking advantage of the wet grass that
effectually deadened the sound of their footsteps, they had turned the
tables on their shadowers.

So completely taken aback were the two lads that they stood stock-still
as if rooted to the earth.

"Not a nice evening to be out, Trefusis," continued the doctor.  "What
brings you on St. Mena's Island at this late hour of the day?"

"Our boat was left high and dry by the tide, so we had to wait and take
shelter," replied Ross.

"And so you chose a place where there was no shelter," remarked
Ramblethorne.  "Idiotic thing to do--very idiotic.  Now tell me: what
were you doing on the top of the tower?"

Ross did not hesitate in his reply.  Perhaps it would have been better
had he done so, for he had never betrayed his knowledge of German to
the doctor on any of their previous meetings, and it would have been
judicious to keep up the deception.

"What were we doing?  Listening to your precious schemes," he retorted
boldly.  "Now we know all about you, and it will be our duty to report
you as spies to the authorities.  We are expecting a search-party from
Killigwent Hall at any moment, you see."

"So that's the line of defence you propose to adopt, eh?" sneered
Ramblethorne.  "Well, look out!"

With a sudden spring the athletic man flung himself upon Ross, while
von Ruhle with equal promptitude made a rush to secure Vernon.

Strong and active though he was, Ross was no match for his huge and
powerful antagonist.  Knowing that flight was impossible, the lad
feinted, and aimed a blow with his left straight for the doctor's chin.
This Ramblethorne parried easily, and grasping the lad's wrist, held it
as in a vice, and in such a manner that rendered fruitless any attempt
on Trefusis' part to make use of his right arm.

Having thus secured his opponent, Ramblethorne watched the result of
the encounter between his fellow-spy and young Haye.

Von Ruhle had opened the attack by brandishing his heavy stick, and
calling upon Vernon to surrender.

Haye returned the compliment by closing, and dealing the German such a
terrific blow upon the chest that von Ruhle recoiled quite a couple of
yards.  The lad's onslaught had only missed the German's solar plexus
by a few inches; had it not, the chances were that von Ruhle would have
lost all interest in life for the next quarter of an hour.

But instead of following up his initial success Vernon, seeing Ross
helpless in the doctor's grip, rushed to his chum's aid.  For a few
seconds he feinted, striving to find an opening, while Ramblethorne,
dragging his captive with him, pivoted in order to keep his front
towards his new antagonist.

Those few seconds were Vernon's undoing.

Quickly recovering himself, von Ruhle sprang forward with the agility
of a panther.  The imitation Malacca cane descended with a dull thud
upon the lad's head, and like a felled ox Vernon fell inertly upon the
sodden grass.

"Hold him--so," exclaimed Ramblethorne, handing Ross over to the
custody of von Ruhle.  Then drawing a small hypodermic syringe from a
case, the former inserted the needle into the lad's forearm.

Five seconds later Ross Trefusis lay unconscious beside his companion
in misfortune.

Kidnapped

"I thought you had killed him, von Ruhle," said the doctor, bending
over Vernon and making a cursory examination of the unconscious lad.

"I thought I had," was the unconcerned reply.  "Dead men tell no tales."

"There I beg to differ," protested Ramblethorne.  "Corpses have a nasty
way of turning up at inopportune moments.  These youngsters are worth
more to us alive than dead."

"How so?"

"One is a son of Admiral Trefusis; his companion is, I believe, also a
son of a distinguished English naval officer."

"Well, and what of it?" asked von Ruhle.

"Hostages," replied the doctor briefly.  "Later I will explain.
Meanwhile we'll carry them to the cave.  It's farther than back to the
ruins; but perhaps, as young Trefusis said, there may be a
search-party, and the ruins would be one of the first objects of
investigation."

Although, with the exception of periodical visits abroad, Dr.
Ramblethorne had lived in England all his life and was a fully
qualified medical man, he was a highly trusted and talented agent of
the German Secret Service.  Months before the outbreak of war, he had
been ordered to report upon the defences of Devonport, and in order to
do this he had bought a practice on the outskirts of Plymouth.  Upon
the commencement of hostilities, he was detailed to keep under
observation the military preparations of the Duchy of Cornwall, and
also to take necessary steps for communicating with German submarines
that, under von Tirpitz's prearranged scheme, were to operate in the
Bristol Channel.  Von Ruhle was one of the few subordinates he actually
knew.  There were others with whom he communicated only through an
intermediary, and who knew him only by a number.

Von Ruhle was almost as mentally clever as his superior.
Ostentatiously he was an Englishman.  Sometimes he posed as a mining
engineer; at others as a commercial traveller; as an accredited
representative of the British Red Cross Society he was in the habit of
making frequent journeys to Holland, presumably in connection with work
at Groningen Internment Camp.  At the present time, his activities were
centred upon the formation of a secret petrol depot for the supply of
fuel to unterseebooten operating in the Bristol Channel and off the
south coast of Ireland.

A couple of slight incidents had served to put the cautious
Ramblethorne on his guard during his interview with von Ruhle in the
ruined chapel.

Although he verbally deprecated his subordinate's alarm when the lads
accidentally dislodged a stone from the tower, it was merely to disarm
possible eavesdroppers of any suspicion that their presence was
suspected.

The ability to control his feelings was one of the super-spy's chief
assets.  Suspicion once aroused, he proceeded without the faintest sign
to investigate his surroundings.  His keen eye soon lighted upon the
lads' sweaters.  Then it was that an adjournment was suggested to Main
Beach Cove.

This was simply and solely a "blind", for on gaining the cover of the
boulder-strewn hillock the doctor communicated his suspicions to his
companion.  The pair then crouched behind the rocks, whence they were
able to command a view of the tower.

It was not long before their enterprise met with success.  They saw
Trefusis and his chum cautiously descend by means of the ivy; then,
directly the lads set out upon their ill-starred tracking expedition,
the Germans, as before related, succeeded in outflanking them and
effecting their capture.

"Time!" announced Ramblethorne, consulting his watch.

"Are these safe?" asked von Ruhle, stirring Vernon's unconscious form
with his foot.

"Quite; though, perhaps, to make sure I will give this youngster a
slight injection.  Pity you hadn't held him with the double arm-lock
instead of cracking him over the head.  Herr Kapitan Schwalbe won't
want to be troubled with a passenger with a swollen head."

Leaving their senseless victims in the cave, the two Germans again
ascended the hill to St. Mena's Chapel.  As they breasted the summit,
they could see the fixed white light of Black Bull Head showing
momentarily brighter and brighter against the rapidly failing daylight.

Setting a prismatic compass in position upon the sill of one of the
glazeless windows, Ramblethorne took a careful bearing in a seaward
direction.  This done, he pointed the projector of the signalling
apparatus in precisely the same direction, and threw a waterproofed
cloth over the instrument.

"Too early yet, von Ruhle," he remarked.  "Nevertheless it is advisable
to fix our bearings while twilight lasts.  A light might spell
disaster."

"A deucedly unpleasant night for such a task," grumbled von Ruhle.

"On the contrary, it is just the very thing," replied the doctor.  "It
is not thick enough to be dangerous, but the rain is just sufficient to
assist in the screening of U75.  Do not think of your personal comfort,
my dear von Ruhle, when urgent work for the Fatherland has to be
undertaken."

For another half-hour the two men paced the grass-grown stones.  Their
choice of St. Mena's Island as a secret signalling station was an
excellent one.  It was isolated, and, being slightly greater in
elevation than the cliffs of the mainland in the immediate vicinity,
would effectually screen any ray of light sent landwards from the
expected German submarine.  Thus all danger of the narrow gleam of
reflected light being detected by the none too smart members of the
coast patrol was entirely obviated.

"Time!" exclaimed the doctor, consulting the luminous face of his watch.

Dexterously, and without disturbing the position of the instrument, von
Ruhle whipped off the covering.  Although there were no visible signs
that anything was taking place, both men knew that a beam of light,
reflected from the distant lighthouse on Black Bull Head, was being
directed seawards.

In silence the two men peered through the driving rain, von Ruhle
making use of a pair of powerful night-glasses.

Suddenly, after an interval of almost five minutes, a faint pin-prick
of light flickered from the surface of the sea.

Instantly Ramblethorne stepped a dozen paces to the right.

"I can see nothing from here," he announced in a low voice.  "Can you?"

"Yes," replied his companion.

"Good: that's friend Schwalbe."

The doctor was right.  From the deck of the unterseeboot a signalling
apparatus similar to that employed by the spies was in use.  By an
ingenious automatic arrangement it projected a beam of light, derived
from the same sources as that on St. Mena's Island, rigidly in a fixed
direction, regardless of the "lift" of the submarine under the action
of the waves.

For several minutes a rapid exchange of signals was maintained; then
the two spies, folding up their apparatus, walked rapidly towards Main
Beach Cove.

They had not long to wait before the faint sound of oars was borne to
their ears.

"Himmel!  They have arrived already," exclaimed von Ruhle.

"So it appears," replied Ramblethorne dryly.  "I pride myself that I
have exceptionally good eyesight, but I fail to see her.  The neutral
colour of the submarine is indeed excellent for night work."

They descended the sandy and shingly beach until further progress was
barred by the lapping wavelets of the rising tide.

Through the mirk loomed up the outlines of a canvas collapsible boat
crowded with men.  At two lengths from the shore the rowers laid on
their oars.  One of the men gave vent to a low whistle resembling the
call of a curlew.

"All clear," replied Ramblethorne.

The boat's keel rasped on the shingle.  A cloaked figure in the
stern-sheets made his way for'ard and leapt ashore.

"Herr von Hauptwald?" he asked.

"The same," replied the doctor.  "And Kapitan Schwalbe?"

"The captain is still on board," replied the officer.  "It is hard to
resist the opportunity of getting ashore after being cooped up there
for more than a fortnight.  But the petrol?"

"We have not so much as we hoped to obtain," replied von Ruhle.

The Leutnant muttered an oath.

"And how is business?" asked Ramblethorne, with a view of distracting
the officer's thoughts from the shortage of fuel.

The Leutnant muttered another oath.

"Bad!" he replied savagely.  "Only one wretched little tramp steamer,
which we fell in with about twenty miles from the Stacks.  She gave us
a run for our money, but we had her at last.  Even then she tried to
ram us.  One has to be most cautious also.  These accursed English have
been far too active with their new-fangled contrivances.  We called up
U71 early this morning.  She replied.  Again at noon we called her, but
there was no reply.  U70 we have lost all touch with since Monday, yet
she was under orders to assist in the blockade of the Bristol Channel
until we, as senior unterseeboot, gave instructions to return to
Wilhelmshaven."

"Lost, I suppose," remarked Ramblethorne.

The Leutnant had walked to a distance of nearly ten yards from his men,
who were drawn up in military order awaiting their officer's commands.

He lowered his voice.

"Although I am sorry to say it," he declared, "I am afraid she has gone
too.  Our losses are not only serious--they are appalling.  Submarine
work is now a continual nightmare.  We do our duty, but before long, if
we are sufficiently fortunate to escape the toils that these English
cast about us, we shall all be physical wrecks."

The man's agitation increased as he spoke.  Obviously he was labouring
under a severe strain.

"And this petrol?" he asked anxiously.  "What quantity?"

Ramblethorne told him.

"Not enough," declared the Leutnant.  "Himmel, it is not enough to get
us round Cape Wrath.  On board we have only sufficient for six hours'
surface running, while our batteries are not far short of running down.
You had better see the captain and explain."

Leaving von Ruhle to direct the seamen to the secret petrol store in
the cave, Ramblethorne accompanied the Leutnant to the submarine.

The U75 was one of the latest type of Germany's submarines.  Over three
hundred feet in length, there was little about her in common with the
accepted idea of under-water craft.  Her deck ran in one continuous
sweep for almost her entire length, and rose nearly six feet above the
surface.  The visible part of her sides was perpendicular, the bulging
sections being entirely beneath the surface.  Her conning-tower was
surrounded by a platform as long as the navigation-bridge of a modern
destroyer.  The two periscopes were "housed", but two slender
"wireless" masts gave the boat the appearance of a swift torpedo craft.

Acknowledging a salute from a burly quartermaster, Ramblethorne gained
the deck, and was escorted aft by the Leutnant.  Pacing the tapering
platform was a broad-shouldered, fair-haired man of about thirty,
although a carefully trimmed blonde beard made him look much older.

He lacked the natural elastic stride of the British naval officer.  His
movements resembled those of a thoroughly drilled soldier, yet ever and
anon he would glance furtively in the direction of the open sea as if
in constant dread of sudden and unknown peril.

"Greetings, Herr von Hauptwald!" he exclaimed, when the Leutnant had
formally introduced his visitor.  "You are well known to me by repute,
but I doubt whether we have met before."

"I fancy so," rejoined the doctor.  "Do you not remember that little
affair in the Strauer Platz?  Ah, I thought you would!  But to come to
the point.  We have been unable to obtain the requisite quantity of
petrol."

"Somehow I thought it," replied Kapitan Schwalbe.  "How much have you?"

Ramblethorne told him.

"Enough, with what we have left on board, for only eight hundred miles
run.  It will not take us home, and we are under orders not to leave
these waters before Friday next.  We have been let down badly."

"I know that it is useless to express regrets," said Ramblethorne
boldly.  "I can only hope that other means of supplying the requisite
fuel will be forthcoming.  But here is another matter.  We have had to
secure two English lads, both sons of distinguished naval officers.
Unfortunately they overheard a conversation between von Ruhle and
myself.  In the interests of the Secret Service it is absolutely
necessary that they are kept out of the way for at least a couple of
months.  I am averse to doing them personal injury."

"Then what do you wish?" asked Kapitan Schwalbe.

"Take them on board with you.  If possible, land them at a German port.
If this be possible, you will realize that we have a strong tool to
work with."

"I fail to understand," said the Kapitan of U75.

"They could be made good use of as hostages," resumed Ramblethorne.
"If these English persist in talking about reprisals, we can hint
that--well, it is unnecessary to go into details."

"I see," remarked Kapitan Schwalbe.  "But if it is impossible to land
them?"

"Then you must put them on board the first outward-bound tramp steamer
you fall in with--provided she is bound for South American ports, or
anywhere that will mean a long voyage."

"Very well," assented the submarine officer.  "I quite understand your
anxiety to get them out of the way."

"Temporarily, mind," added Ramblethorne.

"Precisely.  Herr Rix," he exclaimed, addressing the Leutnant.  "Take
four men and go ashore.  Von Ruhle will tell you where these English
boys are; have them brought on board."

"One moment," interrupted Ramblethorne.  "They came to the island in a
boat.  There is nothing unusual in that, I admit, but the fact remains
that the boat is still lying in the cove next to this.  You might order
the men to set the boat adrift."

"Water-logged, and with sails set and the main-sheet made fast.
Another deplorable accident.  Ach!  It shall be so."

Half an hour later Ross Trefusis and Vernon Haye, still unconscious
under the action of the anaesthetic injection, were brought on board
U75 and passed below.  Their boat, lying on its beam-ends, was drifting
slowly in the direction of Black Bull Head.  Ramblethorne and von
Ruhle, their work for the present done, were already on the way to the
mainland.

Meanwhile, alarmed at the non-appearance of the young heir to
Killigwent Hall and his guest, a party had set off to search St. Mena's
Island.

Just as the boat's keel grounded on the beach of Half Tide Cove, the
German submarine slipped quietly through the blurr of misty rain, and
under cover of darkness headed towards the mouth of Bristol Channel.

CHAPTER IV

The Awakening

"Dash it all!  What am I doing here?" muttered Ross Trevor drowsily, as
he opened his eyes.

For the moment he quite imagined that he was in his dormitory at
school, and that by an oversight the rest of his chums had left him in
bed.  The suggestion was strengthened by the sound of gurgling water,
as if the bathroom tap were running.  Then he became aware that
everything was pitching up and down.  Once before he had experienced a
similar sensation--when he had had a violent headache following a
slight touch of sunstroke.

It puzzled him, too, that he was almost in darkness.  Somewhere
without, and partly screened by some projection, an electric light was
burning.  The reflected rays were just sufficient to enable him to take
stock of his surroundings.

No, he was not back in the school dormitory.  True, he had a headache,
but that would not account for the actual motion.  He fumbled, his
fingers came in contact with a curved board that served to prevent the
occupant of the bed--or, rather, bunk--from falling on the floor.

Almost mechanically he rolled out, and stood supporting himself by
grasping the ledge of the bunk.  The swaying, due partly to dizziness
and partly to an unaccountable see-saw motion, would have thrown him to
the floor but for the assistance afforded by the side of the bunk.

Gradually he became aware that there was a similar sleeping-place
immediately beneath the one he had been occupying.  Someone was lying
there, breathing heavily.  There was sufficient light for Ross to
recognize him.  It was his chum Vernon.

Just then a bell clanged noisily.  The sound of running water was
outvoiced by the loud din of machinery in motion.  A wave of hot air
that reminded the lad of the atmosphere of a Tube station wafted past
him.  The whole fabric trembled under the powerful pulsations of the
mechanism.

With his legs trembling through sheer physical weakness, Ross hung on
grimly.  He wanted to shout, but no sound came from his parched tongue.
He was bewildered.  It seemed as if he were in the throes of a terrible
nightmare, and that he would awake on finding himself falling into a
bottomless abyss.

The reflected light was obscured as a broad-shouldered man made his way
along the narrow corridor in which the bunks were placed.  As he did so
he caught sight of the lad.  Without a word he seized Ross in his arms,
not roughly, but nevertheless unceremoniously, and lifted him back into
the bunk.  There was something so peremptory in the action that Ross
lay still and closed his eyes.  All his will power seemed to have
deserted him.

"Make a dash for it, old man!" exclaimed a muffled voice that Trefusis
hardly recognized as his chum's.  "Make a dash for it.  Don't let them
collar us."

It was Vernon rambling in his sleep.  The words were sufficient to give
Ross a key to the hitherto baffling problem.

Like a flash he recalled the episode of their adventure on St. Mena's
Island.  He remembered himself being held in the grasp of the powerful
Ramblethorne until unconsciousness overcame him.  He was still a
prisoner, but with the qualifying knowledge that he was not alone.
Vernon Haye was sharing his captivity, wherever it might be.

"We're afloat then," he muttered.  "What has happened?"

Moistening his lips, Ross leant over the side of the bunk and called
his chum by name.  His voice sounded strangely unfamiliar.  He could
only just hear himself above the clamorous noise of the engines.

It was not long before another man appeared at the end of the corridor.
As he did so he switched on a lamp almost above the lad's head.  For a
few seconds Ross was temporarily blinded by the sudden transition from
artificial twilight to the intense brilliancy of electric light.

"So!  You are now awake, hein?" asked a guttural voice.  "How you vos
feel?"

"Rotten!" replied Ross emphatically.  His reply was brief and to the
point.  It summed up his sensations during the last ten minutes.

The man laughed.

"So you look.  You better soon will be.  You know where you now vos?"

"On board a ship," answered the lad.  He was still hoping against hope
that his questioner was anything but a German.  There was a small
chance that he had by some means been picked up at sea by a Dutch or a
Swedish vessel.

The man's announcement "put the lid on" that possibility.

"Sheep--goot!" he chuckled.  "German unterseeboot--vot you vos call
submarine.  No danger to you boys if you yourselves behave.  Much to
see--ach! plenty much."

The lad's eyes had now become more accustomed to the light.  He could
see that his visitor was a broad-shouldered, muscular man of average
height, florid-featured, and with light-yellow hair and a fair
moustache.  He was dressed in a uniform that was apparently a bad copy
of that worn by executive officers of the British Navy.  On the breast
of his coat he wore an Iron Cross.

"Me Hermann Rix, Ober-leutnant of unterseeboot," he announced.  "Der
Kapitan send me to see how you get better.  Goot!  I tell seaman to
bring food quick.  In one hour you go on deck.  Den you feel all well."

The German Leutnant bent and peered into the lower cot.

"Fat head," he remarked seriously.  "Bad knock, but he get well soon."

With that the officer went away, leaving the light switched on.

Scrambling out of his bunk, Ross approached his chum.  Vernon was now
sleeping quietly.  His face, however, was flushed, while it was quite
evident that he had received a fairly heavy blow across the skull, for
the top of his head was swollen to a considerable extent.

Before Ross had finished his examination a sailor entered, bearing a
tray on which were three slices of rye bread, some tinned beef, and a
bottle of Rhenish wine.

"Sprechen Sie deutsch?" he asked.

For an instant Trefusis hesitated before replying.  To profess
ignorance of the German language would be an immense advantage while on
board the submarine, provided he could control his facial expressions
and listen without betraying himself.  Then, on the other hand, he
reflected that Ramblethorne, the spy, might have been instrumental in
getting him into this predicament.  More than likely the Captain of the
submarine had been informed of the fact that his unconscious passengers
were well acquainted with the tongue-twisting language of the
Fatherland.

"Here is food for you," said the man, placing the tray on the floor.
"You had better take hold of the bottle before it upsets.  We are
rolling a bit.  When your friend open his eyes, call me.  I am in
yonder compartment.  It would be well for you to dress.  I will bring
your clothes to you very soon."

Ross made a sorry meal.  The food was not at all appetizing.  His
throat was in no condition to enable him to swallow easily.  A feeling
of nausea, due either to the motion, the hot, confined air, or the
after effects of the stupefying injection--perhaps a little of all
three--was still present.

He was actually on board a German submarine--one of Tirpitz's
twentieth-century pirates.  He racked his brains to find a reason.
With its limited accommodation an unterseeboot seemed the last type of
craft that would receive a pair of prisoners--and
non-combatants--within its steel-clad hull.  It must have been at
Ramblethorne's instigation; yet why had not the spy knocked the pair of
luckless eavesdroppers over the head and tumbled them into the sea?  It
seemed by far the easiest solution; yet, in spite of that, Ross and
Vernon were being carried to an unknown destination in one of the
"mystery-craft" of the Imperial German Navy.

The reappearance of the seaman bearing Ross's clothes cut short the
latter's unsolved meditations.  Without a word the man laid the neatly
folded garments on the bunk--a pair of flannel trousers, cricket shirt,
underclothes, and the sweater that had been the cause of the lads'
undoing; but in place of his shoes a pair of half-boots, reeking with
tallow, had been provided.

Ross proceeded to dress.  As he did so a voice that he hardly
recognized asked:

"Hulloa, Trefusis, where are we?"

It was Haye.  His companion was now awake, but hardly conscious of his
surroundings.

"Better?" asked Ross laconically.  He could not at that moment bring
himself to answer the question.

"Didn't know that I was ill," remonstrated Vernon.  Then, after a vain
attempt to raise his head--perhaps fortunately, since the bottom of
Ross's cot was within a few inches of his face--he added:

"Dash it all!  I remember.  That beastly German gave me a crack over
the head with his copper walking-stick.  Where are we?"

"In a rotten hole, old man.  We're in a German submarine, bound
goodness knows where."

"Where are my clothes?" asked Haye, this time successfully getting out
of his bunk.  "Since you have yours, there seems to be no reason why I
shouldn't have mine.  Hang it!  What's the matter with me?
Everything's spinning round like a top."

Mindful of the seaman's words, and with a docility that would have
surprised him in different circumstances, Ross staggered along the
corridor.  The passage was about thirty feet in length.  On one side
the metal wall was flat, on the other it had a pronounced curve.
Against it were six bunks arranged in pairs.  Four were used as
stowing-places for baggage, the remaining ones had been given up to the
two prisoners.  The roof was almost hidden by numerous pipes, most of
them running fore and aft, while a few branched off through the walls.
The flat bulkhead evidently formed one of the walls of the engine-room,
for, as the lad placed his hand against it to steady himself, he could
feel a distinct tremor, quite different from the vibration under his
feet.  The floor was of steel, with a raised chequer pattern in order
to give a better grip to one's feet.  At frequent intervals there were
circular places, similar to those covering the coal-shoots in the
pavement of residential thoroughfares.  Walls, ceiling, and floor were
covered with beads of moisture, but whether from condensation or
leakage Ross could not decide.

At the end of the corridor or alley-way was a steel water-tight door,
running in gun-metal grooves packed with india-rubber.  The door was
closed.

Seizing the lever that served as a handle, Trefusis tried to turn it,
but without success.  Failing that, he kicked the steelwork with his
heavy half-boots, yet no response came to his appeal.

"The fellow told me to call," he muttered airily.  "What did he want to
play the fool for?"

Retracing his steps, Ross went to the other end of the alley-way.
There was barely room to pass his companion as he did so.  The place
from which he had previously seen the reflected light was now shut off
by a door similarly constructed to the one that he had vainly attempted
to open.  He was locked in a steel tomb that was itself a metal box
within a metal box--a water-tight compartment of the submarine.

"They might just as well have switched off the light while they were
about it," he exclaimed bitterly; then at the next instant he wildly
regretted his words.  The idea of being imprisoned in that cheerless
compartment without a light of any description appalled him.

Almost frantically he returned to the door that had previously baffled
him.  As he did so he became aware that the submarine was tilting
longitudinally.  Since he was unaware of the direction of the craft,
and which was the bow or stern, he was unable to judge whether the
unterseeboot was diving, or ascending to the surface.

The incline became so great that he had to grasp the door-lever for
support.  Turning his head, he saw that Vernon was hanging on grimly to
the partition between the tiers of bunks.

Then, as the vessel regained an even keel, silently and smoothly the
door slid back in its grooves, revealing a small space barely six feet
in length and five in breadth, and separated from the rest of the
vessel by a closed water-tight panel.  Part of the compartment was
occupied by a bend, at which the seaman to whom he had previously
spoken was busily engaged in mending a rent in an oilskin coat.

"My friend is now awake," announced Ross.

The man laid aside his work.

"Good!" he replied.  "He is just in time.  I will bring him his food
and his clothes.  After that you will both go on deck for fresh air
before you are interviewed by Herr Kapitan Schwalbe.  See that door?
Beyond that you must not pass without permission.  It is forbidden.  If
you do so, you will not have another opportunity in a hurry."

"What are they going to do with us?" asked Ross.

The sailor shook his head.

"It is forbidden to ask questions," he said sternly.  "Whatever is
necessary that you should know will be told you."

He turned his back upon his questioner, signifying in a plain manner
that it was useless for Trefusis to say more.  Taking the hint the lad
returned to his chum, wondering deeply at the fate that had thrown them
into the hands of the enemy.

CHAPTER V

Aboard U75

Like Ross, Vernon Haye made a poor meal.  He had barely finished when a
petty officer appeared and curtly ordered the lads to follow him.
Since he did so in German it was fairly certain that Trefusis'
admission had been communicated to both officers and crew.

Staggering, they passed along the alley-way into a broad subdivision
that extended completely athwartships.  It was one of the two broadside
torpedo-rooms, and contained two tubes of slightly greater diameter
than the British 21-inch.  In "launching-trays" by the side of the
tubes were eight torpedoes with their deadly war-heads attached.  Both
transverse bulkheads were almost hidden by indicators, voice-tubes, and
pipes for transmitting the compressed air from the air-flasks to the
torpedo-tubes.

Passing through another water-tight door the prisoners found themselves
in yet another compartment.  On one side was an "air-lock", with its
complement of life-saving helmets; on the other was an oval-shaped door
forming means of communication with the small room built against the
curved sides of the submarine.  Ross guessed, and rightly as it
afterwards transpired, that the door led into a space that could be
flooded at will, and which in turn enabled a diver to operate from the
U-boat while submerged.

Confronting the lads was an almost perpendicular steel ladder
communicating with the conning-tower.  Their guide was about to ascend
when a stern voice exclaimed in German:

"Not that, you idiotic clodhopper!  Have you lost your reason?  The
forward hatchway, don't you know?"

"Pardon, Herr Leutnant," said the petty officer, abjectly apologetic,
and, backing down the ladder, he passed through another door entering
into an alley-way between the officers' cabins.  Here was the bowl of a
supplementary periscope, so that a vision of what was taking place
could be obtained without going into the conning-tower.

The alley-way terminated at another broadside torpedo-room, the pairs
of tubes pointing in the opposite direction to those the lads had just
seen.

Beyond were the living-quarters of the crew, kept spotlessly clean and
tidy, yet Spartan-like in their simplicity.  Two of the men were sound
asleep in their bunks.  Three more, who were playing cards at a plain
deal table, glanced up from their game as the British lads passed by;
but their interest was of brief duration, and stolidly they resumed
their play.

Stooping down to avoid a large metal trough--the "house" for the
for'ard 105-millimetre disappearing gun--Ross and his chum arrived at
the ladder by which they were to gain the open air.

The hatch-cover was thrown back.  For the first time during their
captivity they made the discovery that it was night.  Looking upwards,
they could see a rectangle of dark sky twinkling with stars that, with
the slight motion of the submarine, appeared to sway to and fro.

The cool night breeze fanned their heated foreheads as they gained the
deck.  For some time, coming suddenly from the glare of the
electrically lighted interior, their eyes were blinded.  They could see
nothing but an indistinct blurr of star-lit, gently heaving water.

Gradually the sense of vision returned.  They found themselves on the
fore-deck of the unterseeboot.  They had made up their minds to see a
turtle-back deck with a narrow level platform in the centre; instead
they found that the deck was almost flat and, in nautical parlance,
flush, save where it was broken by the elongated conning-tower topped
by the twin periscopes and slender wireless mast.

Lying on the deck in all conceivable attitudes were most of the
U-boat's crew, taking advantage of a brief spell on the surface to
breathe deeply of the ozone-laden atmosphere.

Not a light was visible on board.  Even the hatchway by which the lads
had gained the deck was constructed to trap any stray beam from the
brilliant glare below.

Miles away, and low down upon the horizon, a white light blinked
solemnly; then after a brief interval it was succeeded by a red gleam.
This in turn was followed by white again.

Trefusis, with a sailor's inborn instinct, began to count the
intervals.  Although having no means of consulting the only
time-recording watch in the possession of the two captives, he had a
fair idea of counting seconds.  At fourteen from the disappearance of
the red light the white appeared.  An almost identical space of time
occurred before the red reappeared.

"It's the Wolf Light," mentally ejaculated the lad.

His next step was to fix the bearing of the lighthouse.  This he did by
looking for the Great Bear, and then, following the Pointers, the North
Star.

"Phew!" he muttered softly.  "Nor'-nor'-west.  This brute of a
submarine is right in the chops of the Channel--the main highway for
vessels making for London and the south coast ports."

"What's that?" asked Vernon, who heard his chum speaking, but had
failed to grasp the significance of his words.

"Nothing," replied Ross almost in a whisper.  "I'll tell you later."

The cool air had revived both lads wonderfully.  They had been left to
their own devices, for the petty officer had gone aft.  Those of the
crew who were on deck seemed as apathetic as the men below concerning
the presence of the kidnapped youths.  They looked like men utterly
worn out by fatigue and nervous strain.

Grasping the flexible wire hand-rail Ross continued his survey of the
horizon, all of which was visible except a small portion obscured by
the rise of the conning-tower.  The air was remarkably clear.  Taking
into consideration the refraction of the atmosphere, the navigation
lamps of a vessel shown at twenty feet above the sea would be visible
from the low-lying deck of the submarine at a distance of six to seven
miles.

But there were no signs of any vessels in the vicinity.  The German
submarine rolled lazily in complete isolation, waiting, like a snake in
the grass, for its prey.

"Herr Kapitan would see you," exclaimed the guttural voice of the petty
officer.  "Come aft.  Remember, when you are addressed, to remove your
caps."

The man led the way, making no attempt to avoid the recumbent limbs and
bodies of the crew who impeded his passage.  Treading with discretion
Ross and Vernon followed till, after skirting the base of the
conning-tower, they found themselves in the presence of
Lieutenant-Commander Schwalbe, the Kapitan of U75.

Schwalbe was sitting in a small arm-chair which had been brought from
his cabin.  He was smoking a cigar.  At his elbow stood his satellite,
Hermann Rix, who was also smoking.  This luxury was denied the crew,
the officers being permitted to smoke only when the submarine was
running awash or resting on the surface.

[Illustration: THE INTERVIEW WITH THE GERMAN CAPTAIN (missing from
book)]

"So you have recovered from your little involuntary rest," exclaimed
Schwalbe in excellent English.  He was a remarkably good linguist, for
previous to the outbreak of the war he had been the skipper of a
North-German-Lloyd boat.  By sheer good luck he had reached a home port
the day after the momentous declaration of hostilities, having narrowly
escaped capture by a British destroyer.

Owing to the great expansion of the German submarine service, and its
equally rapid reduction at the hands of the British Navy, the supply of
specially trained officers of the Imperial Navy for this branch had run
out.  More had been transferred from the pent-up High Seas Fleet, while
others had been absorbed from the now useless German Mercantile Marine,
and hastily put through a course of instruction.  Schwalbe was one of
these, and after less than two months' hazardous work in the capacity
of Unter-leutnant found himself in command of U75, one of the "last
words" of von Tirpitz's piratical fleet.

Neither Ross nor Vernon replied.  They could form no suitable answer.
It was no doubt very considerate on the part of the Kapitan to enquire
after their healths, but somehow the lads felt that the skipper of U75
was responsible for their presence on board.

"Come, come," continued Schwalbe.  "Don't be sulky."

"We are not," expostulated Ross.

"I'm glad to hear it," rejoined the Kapitan, with a grin that had the
effect of letting his cigar fall to the deck.  He stooped to retrieve
it, but, suddenly remembering that it was beneath his dignity, changed
his mind and kicked the glowing stump on one side.  Having taken
another from a gun-metal case, he lit it with a device that merely
smouldered instead of giving a bright light.

"It is as well we understand each other," he continued.  "Do you know
why you are on board U75?"

"No, sir," replied Ross.

"Neither do I," rejoined Schwalbe with astonishing candour.  "I wish I
had not been honoured with your company."

"The remedy is in your hands then, sir," said Trefusis.  "You can land
us the next time you put in at St. Mena's Island for petrol, or else
put us on board the first fishing craft we fall in with."

"I beg to differ," was the rejoinder.  "Unfortunately you are on board,
and you must make the best of it, I understand from my friend--shall I
say Dr. Ramblethorne--that you are both very inquisitive.
Inquisitiveness is a bad trait in ones so young.  You see, it has got
you into trouble.  The doctor has strong reasons for getting me to take
care of you for some considerable time, so you will have an opportunity
of seeing how we Germans make war.  No half-measures, mark you.  It is
useless to make war with a velvet glove.  You English people call us
pirates, I believe?"

"It certainly looks like piracy when German submarines sink harmless
merchantmen without warning," declared Vernon.

"For my part I have never sent a merchant vessel to the bottom without
warning," said Schwalbe.  "As a seaman I regret having to sink any ship
of commerce.  As an officer of the German Navy I have to obey orders
unquestionably.  Nevertheless I have always given the crews of British
ships a chance of escape, and have never sunk any vessel until the men
are safely in the boats, unless she attempts to show fight or to run
away."

"Would you blame a skipper for trying to save his ship?" asked Ross.

"You do not understand," exclaimed Schwalbe.  "We are at war.  A
blockade has been declared upon the British Islands.  If, after full
warning, merchantmen persist in taking the risk, it is their look-out,
not mine.  However, to return to a more personal matter: having been
saddled with you, I must endure your presence.  You will be well fed,
as far as the resources at our command will allow.  You will be free to
go wherever you wish on board, with the exception of the conning-tower,
motor- and torpedo-rooms.  I am not ungrateful, for my brother, who had
the misfortune to be in the _Ariadne_, was captured by your fleet.  He
is being well treated somewhere in England.  Hence I give privileges to
the son of Admiral Trefusis and the son of Commander Haye so long as
they are my compulsory guests.  But bear in mind: you will be watched.
Should you commit any fault, however slight, you will pay dearly for
it.  If you are foolish enough to attempt any act of treachery, death
will be the penalty.  Have I made myself perfectly clear?"

"Yes, sir," replied both lads.

"Very well.  Is there anything you would like me to do within the
bounds of reason?"

"Could we communicate with our parents?" asked Ross.

"No," replied Schwalbe decisively.  "There are strong objections.  And,
while I am on the subject, should you fall in with the crews of
destroyed ships you are strictly forbidden to communicate with them
either by word or gesture.  That will be a punishable offence of the
second degree.  Anything more?"

"My friend has had a nasty knock on the head," said Trefusis.  "Have
you a doctor on board?"

Again Kapitan Schwalbe smiled broadly.

"No," he replied.  "There is no need.  Cases of illness must wait till
we return to port.  The only injuries we are likely to sustain would
put us beyond all medical aid.  But several of the men are fairly
skilled in rough surgery, so I will----"

"Vessel on the port bow, sir; she's showing no lights," announced a
voice.

"All hands to stations!" ordered the skipper.

"Down below with you!" hissed the petty officer, who during the
interview had stood rigidly at attention at two paces to the rear of
his charges.

Already the hitherto recumbent men were alert.  Quickly, yet in order,
they disappeared down the fore hatchway, and amongst them were Ross and
Vernon.

The officers had taken their places inside the shelter of the
conning-tower.  Everything was battened down from within, and with a
gentle purr the electric motors were set in motion, while at the same
time water ballast was admitted into the trimming-tanks.

Swift and stealthy had been their preparations, but the presence of the
submarine was betrayed by the phosphorescent swirl of the water caused
by the churning of the twin propellers as she slipped beneath the
surface.

Twenty seconds later a swift vessel that looked suspiciously like a
trawler, although her speed belied her, tore over the place where U75
had disappeared.  Bare inches only separated the top of the latter's
conning-tower from the massive keel plates of the craft that had all
but accomplished its mission.

The watch-dogs of the British Navy were at work.

CHAPTER VI

The Tramp

Like a startled hare the unterseeboot fled for shelter.  Not until she
reached a depth of fifteen fathoms did she check her diagonally
downward course.  At intervals a dull booming, audible above the rattle
of the motors, proclaimed the unpleasant fact that her antagonist was
circling around the spot marked by the phosphorescent swirl and the
iridescence of escaped oil, and was firing explosive grapnels in the
hope of ripping open the U-boat's hull.

Kapitan Schwalbe, looking very grey in the artificial light, was
standing behind the quartermaster.  His hands were clenched in
momentary apprehension.  Beads of perspiration stood out upon his
forehead.  He was experiencing a foretaste of the torment of the lost.

As a submarine officer of the Imperial German Navy he was a failure.
Only sheer luck had hitherto saved him from the fate that had overtaken
scores of his brother officers in that branch of the service.  Skilled
as he was in the handling of a huge liner, he lacked the iron nerve
that is essential to the man who has to risk his life in a steel box
that, in ninety-nine cases out of a hundred, offers no means of escape
in the event of a catastrophe.

Yet he had to do his duty, notwithstanding his utter distaste for
submarine work.  He had had no option.  The officers of the British
Navy volunteer for submarine duties; those of the German Navy are
simply told off whether they want to or not.

The nerve-racking work was beginning to tell upon him.  His orders
condemned him to a forlorn hope, for the English Channel was known to
be a death-trap for the under-sea blockaders.  The sight of a trawler
filled him with feelings akin to terror.  The possibility, nay
probability, of a merchantman carrying guns made him approach his
intended prey with the utmost caution; yet, as he had remarked to Ross
Trefusis, he had never torpedoed any vessel flying the red ensign
without giving her warning.

But it was not chivalry that prompted Schwalbe to act with
consideration.  Had he been untrammelled he would have sent his prey to
the bottom without compunction, for he had all the brutal instincts of
the kultured Hun.  It was a superstitious fear that held his
frightfulness in check--a presentiment based upon the Mosaic Law, an
eye for an eye and a tooth for a tooth.

Having placed a considerable distance between him and his attacker,
Kapitan Schwalbe ordered the electric motors to be stopped.  The
ballast tanks were "blown", and cautiously U75 rose to the surface.

It was the best course open to her.  The depth of the water was much
too great to allow her to rest on the bed of the sea.  On the other
hand, in order to keep submerged, the motors would have to be in
motion.  No one knew better than Schwalbe that the British patrol-boats
would be in a position to locate with uncanny certitude the presence of
their quarry, unless the strictest silence were maintained by the
fugitive.

So, ready to dive at the first alarm, U75 floated awash until such
times as were considered favourable for getting under way.  Decidedly
this part of the English Channel was, for the time being at least,
unhealthy; and Kapitan Schwalbe resolved to make for the Bristol
Channel, where the dangers of being destroyed by modern mosquitoes were
more remote.

Meanwhile Ross and Vernon had been sent back to the quarters in the
alley-way, by the side of the motor-room.  Not knowing the reason for
the U-boat's sudden submergence, and consequently unaware of the danger
that threatened her, they formed the erroneous impression that the
submarine was about to attack.

"The old fellow gave us a pretty straight tip," remarked Vernon, when
the chums found themselves alone.  "All the same, I vote we get out of
it at the first opportunity, favourable or otherwise."

"'Ssh," whispered Ross.  "Someone might be listening.  I don't see how
you propose to clear out, though."

"We were on deck just now."

"We were," agreed Trefusis.

"It was fairly dark.  All the men up for'ard were lying down.  It would
have been an easy matter to have dived overboard and swum for it, if we
hadn't been twenty miles or more from land."

"There was a bright look-out kept, all the same," objected Ross.  "And
I wouldn't mind saying that if the submarine were closer inshore,
getting a supply of petrol, for example, we should be closely watched.
All the same, I'm with you if we get the ghost of a chance.  But it's a
rummy affair altogether.  Fancy that chap knowing our names and the
rank of our respective fathers."

"Ramblethorne must have told him that," said Vernon.

"I suppose so; but for what reason?  By Jove, if we get out of this
mess all right, we'll have something to talk about--having been
prisoners on a German submarine!"

The lads were not allowed on deck again that night.  Acting upon Haye's
suggestion they "turned in", and slept fitfully until awakened by the
noise of the watch being relieved.

The seaman, Hans Koppe, brought them their breakfast.  The meal
consisted of fish, coffee, and the usual black bread.  By this time the
captives had practically recovered from the effects of the injection.
Haye's head was still painful, although the headache had left him.

They ate with avidity, owing possibly to the atmosphere of the confined
space, which was highly charged with oxygen.

"What is the Captain's name?" asked Ross, when the man came to remove
the breakfast things.

The sailor told him.

"Where are we now?" enquired Vernon.

The man winked solemnly.

"Afloat," he replied.  "Be content with that."

Just then there were unmistakable signs of activity on the part of the
submarine crew.  Several men hurried along the alley-way, each with a
set purpose.  They paid little heed to the Englanders as they passed.

At their heels came Herr Rix, the Leutnant of the submarine.  He was
beaming affably.

"Goot mornings!" he exclaimed.  "You come mit me, den I show you how we
blockade."

He led the way to the compartment in which the bowl of the
supplementary periscope was placed.  It was now broad daylight, and
consequently the bowl showed a distinct image.  A junior officer was
standing by, but on seeing Rix approach he saluted and moved aside.

"Look!" exclaimed the Leutnant.

Both lads peered into the bowl.  On its dull sides, an expanse of sea
and sky was portrayed.  Beyond that they could see nothing, until Rix
called their attention to a small dark object.

"Englische sheep!" he declared.  "Now you vos watch."

He touched a metal stud.  Instantly an arrangement of telescopic lenses
came into play within the tube of the periscope, with the result that a
small portion of the view was greatly magnified upon the object card.
It revealed a tramp of about nine hundred tons.  She had a single
funnel painted black, with two broad red bands; two stumpy masts, with
derricks, and a lofty bridge and chart-house abaft the funnel.  She was
wall-sided.  Her rusty hull was originally painted black.  Here and
there were squares of red lead, showing that her crew had been engaged
in trying to smarten her up before she reached port.  Aft, frayed and
dirty with the smoke that poured from her funnel, floated the red
ensign.

The submarine began to rise.  Although she tilted abruptly, the image
of the tramp steamer still remained upon the object bowl.  By an
ingenious arrangement, the lenses were constructed to compensate for
any deviation of the tube of the periscope from the vertical.  The lads
could see the bows of the U-boat shaking clear of the water, throwing
cascades of foam off on either side as the passing craft forged ahead
at at least eighteen knots.

Now, for the first time, the skipper of the tramp saw the danger.  He
was a short, thick-set man, with white hair and an iron-grey moustache,
and a face the colour of mahogany.  For an instant he grasped the
bridge-rails and looked towards the submarine, then gesticulated
violently to the man at the wheel.

The spikes ran through the helmsman's hands, as he rapidly revolved the
wheel actuating the steam steering-gear.  The tramp swung hard to port,
with the idea of baffling the momentarily expected torpedo.

Kapitan Schwalbe acted up to his principles.  In any case he was loath
to use a torpedo upon a comparatively small vessel.  In response to an
order, half a dozen of the submarine's crew swarmed on deck, three
going for'ard and three aft.  Within forty-five seconds the two
disappearing guns were raised from the water-tight "houses".

Ross, Vernon, and the German Leutnant remained gazing into the bowl of
the periscope.  The vision so absorbed the attention of the two lads
that they hardly heeded the presence of Herr Rix, who occasionally
emitted grunts of satisfaction or annoyance as the scene was enacted.

The bow gun spat viciously.  The range was but three hundred yards.
The missile passed a few feet in front of the tramp's bows, and,
throwing up a shower of spray that burst inboard on the British
vessel's fo'c'sle, ricochetted a mile or so away.

The tramp's skipper showed his mettle.  Round swung the vessel, listing
heavily as she did so.  By this time the call for more steam had been
responded to, and dense clouds of black smoke belched from her funnel,
mingled with puffs of white vapour as the siren bleated loudly for aid.

Running awash, U75 had a great advantage of speed; overtaking her prey
she was able to send half a dozen shells into the lofty target
presented as she slid by.

Holes gaped in the thin plating close to the waterline.  A shell,
passing completely through the funnel, demolished the siren.  Being
without wireless, the tramp was now without means of long-distance
signalling.

Another missile hit the chart-house and, exploding, swept the frail
structure overboard in a thousand fragments.  The old skipper, hit by a
splinter of wood, fell inertly upon the bridge; but the next instant he
staggered to his feet, bawling to the crew to get the hand-steering
gear connected.

"He's down again!" exclaimed Ross breathlessly, as the brave old man
dropped upon the shattered planking of the bridge.  "Hurrah!  He's
still alive."

The skipper had deliberately taken cover behind the slender shelter
afforded by the metal side-light boards.  By the frantic movement of
his arm, it was evident that he was exhorting his men to "stick it"
like Britons.

The hail of shells continued.  Already fire had broken out on board in
several places.  A sliver of metal sheered through the ensign staff.
Without hesitation one of the crew rushed off, retrieved the
weather-worn bunting, and made his way to the mainmast.

Slowly and deliberately he re-hoisted the ensign until it fluttered
proudly from the truck, then with apparent unconcern the man
disappeared below.

By this time the tramp was again under control, with a course shaped
for land, which lay about ten miles to the S.S.E.  It was, however, a
foregone conclusion that unless help were speedily forthcoming the
vessel was doomed.

The tramp began to heel, almost imperceptibly at first, then with
increasing speed.  She had received her _coup de grâce_.

Still the engines were kept going full speed ahead.  The dauntless
skipper remained on the bridge, with a look of grim resolution on his
weather-beaten features.

Slowly the vessel's way diminished.  Her bow-wave, owing to the
gradually increasing draught, was greater, but less sharp than before.
In a few minutes the water would be pouring over her fore-deck.

Seeing that their work was completed, the pirates ceased fire, the
guns' crews standing with folded arms and stolidly watching the tramp
as she struggled in her death-throes.

Presently a vast cloud of steam issued from her engine-room.  The
inrush of water had damped her furnaces.  The engineer and firemen,
their faces black with coal-dust and streaming with moisture, hurried
on deck.

For another quarter of a mile the doomed vessel carried way, then came
to a sudden stop.  As she did so she gave a quick list to starboard,
until only a few inches of bulwark amidships showed above the waves.

Then, and only then, did the skipper give orders for the boats to be
lowered.  In an orderly manner the crew manned the falls, and the task
of abandoning the ship began.

Without undue haste, the crew dropped into the waiting boats, each man
with a bundle containing his scanty personal effects wrapped up in a
handkerchief.  The Captain was the last to leave.  He did so
reluctantly, his left hand tightly grasping the ship's papers.

Having rowed a safe distance from the foundering vessel, the men rested
on their oars, and waited in silence for the end.  It was not long in
coming.

The tramp was heeling more and more, and slightly down by the bows.
Suddenly she almost righted; then, amid a smother of foam as the
compressed air burst open her hatches, she flung her stern high in the
air.

Even then she seemed in no hurry.  The after part from the mainmast
remained in view, the now motionless propeller being well clear of the
water.

For quite a minute she remained thus, then with a quick yet almost
gentle movement slid under the waves.  The last seen of her was the
weather-worn red ensign still fluttering from the truck.

The periscope's bowl showed nothing but an expanse of sea and sky, and
the two boats rising buoyantly to the waves.

A grim chuckle brought Ross and Vernon back to their surroundings.
Herr Rix was rubbing his hands and grunting with evident satisfaction.

"Goot!" he ejaculated.  "Now, how you like dat?  Now you see how we
German make blockade, hein?"

"A brave deed," replied Ross scornfully, and, gripping Vernon by the
arm, led him back to their uncomfortable quarters in the alley-way.

CHAPTER VII

On the Bed of the Sea

For the next twenty-four hours nothing exciting occurred.  The U-boat
kept to the surface as much as possible, running under her petrol
motors at fifteen knots.  To exceed that pace would mean too great a
consumption of fuel, and already the vessel was short of petrol.

Kapitan Schwalbe was prone to act on the side of extreme caution.
Having sunk one vessel, he would not tackle another in the same
vicinity.  He invariably put at least a hundred miles between him and
the scene of his latest ignominious exploit before attempting another
act of kultur.

Three times during that twenty-four hours he dived: twice on sighting
what were unquestionably Bristol Channel pilot-boats, and on the third
occasion when a Penzance lugger under motor-power (for it was a dead
calm) crossed his track.

All this time a regular stream of shipping was passing up and down the
Bristol Channel, as unconcernedly as in the piping days of peace.  To
anyone but a bumptious German, the sight would have told its own tale;
for the British Mercantile Marine, used to danger and difficulties, was
not to be deterred by the "frightfulness" of von Tirpitz's blockade.
On the contrary, the possibility of falling in with a hostile submarine
gave an unwonted spice to the everyday routine of the toilers of the
sea.

After breakfast on the following morning Ross and Vernon were told to
go on deck.  The sea was still calm, and the submarine, now running
awash at full speed, was cleaving the water with practically dry decks.

The lads soon realized what was in progress.  A couple of miles away
was a large ocean cargo-boat, outward bound, and U75 was in pursuit.

Trefusis and his chum were not allowed for'ard, where the quick-firer
was already in position for opening fire.  They were ordered abaft the
conning-tower, the hatch of which was open.

Kapitan Schwalbe's head and shoulders could be seen projecting above
the opening.  On the raised grating surrounding the conning-tower,
stood a boyish-looking Unter-leutnant.  Hermann Rix was nowhere to be
seen.  Apparently his duties compelled him to remain below.

Presently the quick-firer barked, and a projectile struck the water
about a hundred yards from the starboard side of the pursued vessel.
With the discharge of the gun, a sailor hoisted the black cross ensign
of Germany from a small flagstaff aft, while a signal in the
International Code ordering the British vessel to heave to instantly
fluttered from the light mast immediately abaft the conning-tower.

The only response from the chase was the hoisting of the red ensign,
for previously she had shown no colours.  Slowly, defiantly, the
bunting was hauled close up, and ironically "dipped" three times.

Again and again the submarine's bow-chaser fired.  The shells were well
aimed as regards direction, but all fell short.  Imperceptibly the
merchantman had increased distance.

"Look at the fools!" Ross heard the Kapitan remark, as he kept his
binoculars focused on his intended prey.  "They are trying to snapshot
us.  Are all Englishmen so blind to peril?"

"Are you sure they haven't a couple of quick-firers mounted aft, sir?"
asked the Unter-leutnant.  "There are several men gathered round
something on the poop."

"Himmel, I hope not!" ejaculated Schwalbe.  "But no; had they any guns
they would have opened fire before now.  What is the matter with our
gun-layer?  It is about time he got a shell home."

The Unter-leutnant lowered himself on the foredeck, and shouted angrily
at the seaman whose duty it was to "lay" the bow-chasers.  The man
again bent over the sights.

This time the shell pitched ahead of the chase, but slightly to port.
Some of the spray thrown up by the projectile fell on board.

"Is that the best you can do, you brainless idiot?" shouted Schwalbe
wrathfully.  Now that he was in pursuit he was loath to be baffled, but
at the same time he realized that the submarine was using a lot of
precious fuel and a prodigious amount of ammunition without any
definite result.

In the midst of his torrent of abuse directed upon the luckless
gun-layer, Kapitan Schwalbe suddenly stopped.  Gripping the rim of the
oval hatchway he gazed, horror-stricken, at two objects bobbing in the
water directly in the path of the submarine.  Then, recovering his
voice, he shouted to the quartermaster to port helm.

The fellow obeyed promptly, but it was too late.  Practically
simultaneously, two barrels swung round and crashed alongside the
submarine's hull.

Officers and men, expecting momentarily to find themselves blown into
the air, stood stock-still.  Then, as nothing so disastrous occurred,
Schwalbe gave orders for easy astern.

The barrels, connected by a span of grass rope, had been thrown
overboard from the pursued vessel, in the hope that the submarine would
foul her propellers in the tangle of line.  Once a blade picked up that
trailing rope, the latter would coil round the boss as tightly as a
band of flexible steel.

The plan all but succeeded; only the metal guards protecting the
propellers saved them from being hopelessly jammed.  Yet the attempt
was attended with good results as far as the British ship was
concerned, for by the time U75 had lost way and had cautiously backed
away from the obstruction, the swift cargo-vessel had gained a distance
that put her beyond all chance of being overhauled.

Infuriated by his failure, Kapitan Schwalbe went aft and descended into
his cabin.  He was hardly conscious of the presence of his two
involuntary guests as he passed.  He was thinking of the fate that had
consigned him to a perilous and uncongenial task.  Without doubt the
vessel he had been pursuing was equipped with wireless, and by this
time a number of those dreaded hornets would be tearing towards the
spot.  To add to his discomfiture it was reported to him that the
reserve of fuel on board had seriously dwindled.  In order to remain
effective it was necessary that U75 should replenish her tanks before
another forty-eight hours had passed.

According to his customary tactics, Schwalbe ordered the submarine to
dive to sixty feet.  At that depth she would be safe from any
possibility of being rammed.  Provided she could avoid the under-water
obstructions with which the British naval authorities had sown the bed
of the sea at almost every point likely to be frequented by lurking
hostile submarines, she was in no actual danger.

Gaining his diminutive cabin, Schwalbe by sheer force of habit
consulted the aneroid.  The mercury was falling rapidly.  Since he last
looked, barely two hours previously, it had dropped 764 to 734
millimetres, or an inch and two-tenths.  That meant that the
anti-cyclone was rapidly breaking up, and that a severe gale was
approaching with considerable swiftness.

U75 must submerge and seek shelter.  It was impossible for her to keep
at a uniform depth unless she maintained steerage-way; that meant a
great demand upon her storage batteries.  She could not remain on the
bottom of the sea in a heavy gale, owing to the constant "pumping" or
up-and-down movements caused by the varying pressure of passing waves,
unless she sought a sheltered roadstead--and sheltered roadsteads were
generally mined, or guarded by some ingenious device that had already
accounted for several of U75's consorts.

Producing a chart of the Bristol Channel, Schwalbe unfolded and spread
it upon a table.  Then, in conjunction with a translation of the latest
British Admiralty guide to the west coast of England, he proceeded to
select what he hoped would be a snug shelter during the coming storm.

"Herr Rix!" he shouted.  "I'll make for this anchorage.  There's every
indication of a strong blow from the nor'-east."

"This" was Helwick Channel, a deep, almost blind passage between the
Glamorgan coast and an outlying submerged reef known as the East and
West Helwick.  In fine weather it was a short cut for traders plying
between Llanelly and Swansea.  In bad weather it was a place to be
avoided, as far as sailing vessels were concerned.  Sheltered by the
bold outlines of Worm's Head, it ought to prove an ideal lurking-place
until the gale had blown itself out, for there was little danger of the
place being used as an anchorage, since vessels preferred to give the
rock-bound coast a wide berth.  On this account, it was also highly
probable that the Helwick channel had not been safe-guarded by the
British naval authorities.

Just before sunset, U75, having made the passage unobserved, brought up
in twelve fathoms of water, resting evenly on the firm, hard sands at
the bottom.

Ross and his chum turned in early.  There was nothing for them to do.
They held aloof from the crew; there were no books to entertain them,
no games to amuse them.  The submarine was now motionless, sufficient
water ballast having been taken in to allow her to settle firmly upon
the bottom; but, in order to be prepared, the anchor was let go.  Thus
not the slightest movement of the hull was apparent.  The rest, after
hours of erratic movement on the oily swell, was a welcome one.

The lads had set their joint watch by the submarine's time, which,
being mid-European standard, was one hour fast of Greenwich.

For several hours they slept soundly and undisturbed.  Suddenly they
were both awakened by the muffled tramp of men in heavy sea-boots.  The
solitary light in the alley-way was switched off; the water-tight doors
were firmly closed.  Already the air in the confined space was stifling.

"What has happened?" asked Vernon anxiously, for the vessel, instead of
resting immovably upon the bed of the channel, was now rolling
sluggishly.  Yet she could not be under way, for the motors were silent.

Springing from his bunk, Ross felt for the switch of the electric
light.  It was already down, yet the flow of current was interrupted.

"Let's find out," he said.  "Come along."

The lads, before turning in, had carefully laid out their clothes, so
as to be ready to slip into them at a moment's notice, yet it was a
matter of considerable difficulty to dress in the dark.

"The door's closed," announced Ross as the lads groped their way to the
end of the alley-way.

"I believe the submarine's holed," suggested Haye.

"No; she wouldn't lift as she's doing.  Besides, the crew are moving
about.  Let's bang on the door with our boots."

For several minutes they hammered, but without result.  The air, never
very fresh, was now almost unbearable, owing to lack of ventilation.
The imprisoned youths began to get desperate.

Then, without warning, the door slid back.  The alley-way was flooded
with brilliant light.

"Make haste!" shouted a voice which the lads recognized as that of Hans
Koppe.  At the same time he grasped Ross by the shoulder and literally
dragged him across the steel threshold.  Vernon followed quickly, but
barely had he gained the compartment beyond than the massive steel door
shot back again.

"Didn't you hear the order all hands for'ard?" asked Hans, not
unkindly, for the white faces of the English lads told their own tale.

"No," replied Ross.  "Besides, we are not included in the 'hands', are
we?"

"You'll have to bear the consequences if you don't obey," rejoined
Koppe.  "I'm supposed to be looking after you, but how was I to know
you hadn't turned out?  Fortunately for you, I heard your knocking, and
asked Herr Kapitan to open the doors.  He was angry, but did so."

"What has happened then?" asked Trefusis, for the seaman seemed in a
communicative mood.

"A shift of wind.  It's blowing great guns up aloft, and there's a
terrific tumble into this channel.  We've dragged, or, rather, swung
round our anchor."

"But we are safe enough?" asked Vernon.

"Yes, safe," replied Hans.  "Too safe; we cannot break out our anchor.
They are sending a diver to see what is amiss."

Evidently the diving arrangements on board were not considered to be of
a confidential nature, for Hans led the way to the compartment under
the fore-hatch, without the lads being sent back by the significant
word "verboten".

A man was preparing for a submarine walk.  He was already dressed in an
india-rubber suit, with leaden weights attached to his chest, back, and
boots.  Two others were standing by, ready to place the helmet over his
head, when Leutnant Rix had finished giving him minute directions.

The officer spoke rapidly and in a low tone.  Ross could not catch all
he said, but the words "gefährliche Strömungen" (dangerous currents)
and "Der Wendepunkt der Flut" (slack water) and "Drei Viertel funf" (a
quarter to five) occurred frequently.

Vernon glanced at his watch.  It was then a minute after four.
Apparently Rix was impressing upon the man that he must clear the
anchor at slack water, which occurred at a quarter to five.

The two attendants then proceeded to place the diver's helmet on his
head.  The lads noticed that it had neither air-tube nor telephone
wire.  Nor was there a life-line attached to his waist.  Fresh air was
obtained from a metal case strapped to his back.  The man was able to
work independently, and without having to rely upon his air supply from
the submarine.

The oval door in the diving-chamber was thrown open.  The diver
entered, and the water-tight panel was quickly replaced.  One of the
seamen thrust over a short lever, and immediately water rushed into the
small compartment.  As soon as the space was filled the diver was able
to open a similar door in the outer plating of the submarine, and thus
gain the bed of the sea.

Presently Leutnant Rix turned, and saw for the first time that Ross and
Vernon were discreetly standing in the background.

"Go away.  It is forbidden!" he shouted angrily.

They obeyed promptly, retreating to the space allotted to the crew,
since it was neither desirable nor possible to return to their bunks.

For some minutes the luckless Hans Koppe was subjected to a severe
dressing-down by his hot-headed officer, and when at length the seaman
rejoined the lads he was in no humour to resume conversation.

Slowly the minutes sped.  The submarine was still rolling sluggishly,
in spite of the fact that more water had been admitted into the ballast
tanks.

The men were talking seriously amongst themselves.  From scraps of
conversation that drifted to the lads' ears, it was evident that they
had grave doubts concerning the ability of the diver to perform his
task, and even of his chances of regaining the submarine, owing to the
violent disturbances of the water.

Presently the motion of the anchored submarine became more acute.  A
weird grating sound--the noise made by the hull rasping over the bed of
the sea--was distinctly audible.

One of the seamen produced a pocket compass.  His startled exclamation
brought other members of the crew around him.  The magnetic needle was
apparently describing a semicircle.  U75 was swinging round her anchor.

Just then a bell tinkled, and a disc oscillated on the indicator board
on the bulkhead.  Instantly the two men who had been told off as
attendants upon the diver hurried aft, while their companions crowded
expectantly around the door.

The two men came back, staggering under the weight of the diver.  They
had already removed his head-dress and leaden weights.  Water dropped
from his rubber suit.  His face was livid, his eyes wide open and
rolling.  One of his bare hands was streaked with blood that flowed
sullenly from a cut in his numbed flesh.

Kapitan Schwalbe and Leutnant Rix followed him into the crew-space.  It
was not through feelings of compassion that they had come for'ard.  It
was acute anxiety to hear the diver's report.

The luckless man was laid upon the mess-table.  His attendants divested
him of his diving-suit, and rubbed his body with rough towels.  A petty
officer poured half a glass of brandy down his throat.

"What is amiss?" Kapitan Schwalbe kept on repeating.

With a great effort the diver sat up.

"An anchor, sir," he gasped feebly.  "An anchor--an English naval
pattern one--has been dropped right over ours.  A very big one."

Then his eyes closed, and he fell back unconscious.

"Gott in Himmel!" ejaculated Rix.  "We are trapped!"

CHAPTER VIII

Balked by a Sea-plane

"How so?" demanded Kapitan Schwalbe.  "If we keep quiet, the
cruiser--for cruiser she must be, judging by the fellow's
description--will weigh and proceed."

"When she does weigh we are undone," said Rix despondently.  "We are
swinging round our anchor.  For all we know, our cable has taken a turn
round hers.  As soon as they heave up their anchor, our anchor and
cable will be brought up with it, and then the game is up.  Either the
strain will overcome our dead weight and we will be hauled to the
surface, or else they'll lower one of their brutal explosive charges."

"The situation is serious," admitted Schwalbe in a low tone, for his
Leutnant's words had produced a demoralizing effect upon the men.  "How
much cable have we inboard?"

Rix repeated the question.  A petty officer doubled forward to consult
the cable indicator.  U75's anchor, when under way, was housed in a
trough on the under side of the submarine's forefoot.  The cable was
automatically ranged in a compartment between the inner and outer
skins, the space being always filled with water.  The inboard end of
the cable was not shackled; but to prevent its being able to take
charge and run out, an indicator was placed on the bulkhead nearest to
the cable tier.  The amount of chain let go was regulated by a
compressor, which was actuated from within the hull by means of levers
and cranks, watertight glands being provided to prevent any leakage
into the interior of the submarine.

"Seventy-five fathoms," reported the petty officer.  "When we commenced
to swing we paid out the length we had taken on board when we hove
short."

"We must sacrifice the lot, Herr Rix," decided Kapitan Schwalbe.
"There is no time to lose.  Storm or no storm, we must slip and run for
it."

It was U75's only chance, but it left her with only a small stockless
kedge-anchor and chain, insufficient to withstand a heavy strain.

The compressor was released.  With a loud rumble, for every sound was
magnified within the confined space, the rest of the cable was allowed
to take charge.  It did so promptly, the end of the chain giving the
hull a defiant smack as it did so.  U75, no longer held by her anchor,
began to drift with the tide, scraping dismally over the bed of Helwich
Channel.

Schwalbe was now back at his post in the conning-tower.  He dare not
take the submarine to the surface until he had put a safe distance
between him and the anchored British warship.  Nor did he care to order
the ballast tanks to be blown.  Rather than allow the "pumping" of the
seas to hammer the submerged craft upon the hard sand, he preferred to
take the risk of letting her drag.

Fortunately the tide set evenly along the bed of the channel.  A
cross-current would have set the submarine upon the jagged rocks of the
hidden West Helwick Ridge.  Nevertheless there was always the danger of
being hurled violently against a detached rock, or of fouling a live
mine if by chance the British had laid obstructions in the channel.

Both Ross and Vernon knew the danger, but, manfully concealing their
misgivings, they watched the faces of those of the crew who were "watch
below".  Most of the men were Frisians, broad-shouldered,
blonde-featured, and generally devoid of fear.  Yet the ceaseless
strain upon the nerves had already begun to tell.  As hardy fishermen,
they would not have hesitated to launch their open boats in a storm to
go to the rescue of a hapless vessel aground on the grim sand-banks of
the Frisian shore.  As the conscript crew of the submarine, compelled
to keep within the limits of a steel box that almost momentarily
threatened to be their tomb, their natural bravery was quenched.

Many of them sat upon their lockers, stolid-faced men who had already
tasted of the bitterness of death.  Others showed unmistakable signs of
excitement, bordering on frenzy.  They dreaded their life of modern
piracy.  The idea of sinking hapless merchantmen was repugnant to them,
for they understood the brotherhood of the sea.  It would be different
if they were called upon to attack an armed British ship of war.  They
had no option but to obey their junker officers, who in turn were
compelled to accept the misguided orders of the arch-pirate, von
Tirpitz.

They were disheartened, too, for reports, in spite of the vigilance of
the officers to conceal them, had reached them of the losses inflicted
upon other unterseebooten.  Occasionally they heard of a submarine crew
being saved, but generally it was a case of total loss of all on board,
by some hitherto unknown means, at the hands of the British Navy.

A hand touched Ross lightly on the shoulder.  Turning, he saw Hans
Koppe standing in a darkened corner of the compartment.

"Can you tell me this, mein herr?" asked the seaman in a low tone.  "Is
it true that the English give no quarter to German seamen in
submarines?"

"I shouldn't think that they would refuse to do so," replied Trefusis.
"Of course, I can quite understand that an opportunity doesn't often
occur; but I've heard of several instances in which your U-boats have
surrendered, and the crews have been treated exactly the same as other
prisoners of war."

"I have heard differently," said Hans, "but I hope it's a mistake.  I
have a feeling that we won't see Wilhelmshaven again.  And I have a
wife and six children at Flensburg.  Our Kapitan, too, expects that we
might be denied quarter, because we have sunk your merchantmen.
Believe me, I regret having done so, but we have orders.  Do you know
why Kapitan Schwalbe took you on board?"

"Because a certain German agent wanted us out of the way, I suppose,"
replied Ross.

"Perhaps," admitted Hans Koppe.  "But in the event of our being
captured he thinks that his good treatment of you will be in his
favour.  We are, I do not mind telling you, in a very tight corner.
Our fuel supply is almost run out.  We cannot hope to return home by
way of the Straits of Dover.  Not one of our submarines has tried that
passage of late without meeting with disaster--at least, so I heard der
Kapitan tell der Leutnant.  Ach!  It is deplorable, this war."

The rapid ringing of a gong was the signal for the watch below to turn
out.  A peculiar hissing noise proclaimed the fact that the ballast
tanks were being emptied.  U75 no longer grated over the bottom; her
motors were running almost dead slow.

Although submerged, the submarine was "pumping" violently.  Seasoned
men were prostrate with sea-sickness.  The air, in spite of chemical
purifiers, was becoming almost intolerable.  Everything movable was
being thrown about in utter disorder, while to add to the discomfort of
the crew the covering-plates of one of the lubricating-oil tanks had
been strained, and at every jerk jets of viscous fluid would squirt
through the fracture and trickle sullenly over the floor of the
crew-space.

Since the watertight doors were still closed, Ross and Vernon were
unable to get back to their bunks.  Feeling thoroughly wretched, they
were glad to accept Hans Koppe's offer to lie down on a long locker.

At noon, U75 came to the surface.  The storm, being short forecasted,
had quickly blown itself out, but the waves still ran high.

It was a prearranged plan on the part of the three U-boats operating in
the English and Bristol Channels to communicate with each other by
wireless at noon and at midnight.  U75's wireless had a range of about
180 miles, and although it could be "jammed", the call could not be
tapped by vessels other than the one for which it was intended.  To
make doubly sure, the messages were sent in code.

For nearly ten minutes U75 "made her number" without eliciting any
reply.  Perhaps it was well that Kapitan Schwalbe did not know what had
happened to her consorts.  U74 was at that moment lying on her side at
the bottom of a Welsh harbour, her crew poisoned by the chlorine fumes
from her batteries--the result of a rash curiosity on the part of her
Lieutenant-Commander to investigate the approaches to the anchorage.
As for U77, she was flying blindly for safety, with a couple of
destroyers hard on her track, and a naval sea-plane overhead to direct
them in their search.

Foiled in her efforts to get in touch with her consorts, U75 remained
awash.  The heave of the sea made it most difficult for her to use her
periscope with certainty, for she had chosen a bad pitch on her
ascent--the furious "overfalls" or "tide-rips" to the west of Lundy
Island.

"We'll pay another visit to St. Mena's Island, Herr Rix," decided
Kapitan Schwalbe, after the two officers had discussed the sinister
matter of their futile attempt to make use of the wireless.  "To-night
at nine o'clock ought to suit.  If we cannot get von Ruhle to see our
signals--for my own part, I doubt whether he is in these parts--we'll
have to do our best to get ashore.  Meanwhile, keep a bright look-out.
If we see any likely vessel coming this way, we'll try our luck once
more."

"Message just received, mein herr," announced the wireless operator.

"From whom?" enquired Kapitan Schwalbe eagerly.  He was devoutly hoping
that either U74 or U77 had been able to "call up".

"I cannot say, sir," replied the man as he handed a code message to his
superior.

Decoded, the "wireless" was as follows:

"Station 41 to unterseebooten.  Two hundred gallons of fuel available
here.  Will be on the look-out for signals at 1 a.m."

The message was a "general call" for a secret petrol depot to any
German submarine operating in the vicinity.  Reference to the list of
stations showed that "41" was at Port Treherne, a remote cove on the
North Cornish coast about fifty miles from St. Mena's Island.

"I suppose it's safe," remarked Rix.

"With due precautions--yes," rejoined Kapitan Schwalbe.  "At any rate,
petrol we must have.  Where's the chart?  Ah, there we are!  It looks a
fairly easy place to approach, don't you think?  The only danger from a
navigation point is apparently this ledge of rocks--Lost Chance Reef,
it's called.  What unpleasant names these Englishmen give to their
coasts!"

At that moment the Unter-leutnant, who happened to be at the
conning-tower periscope, reported that a large vessel was bearing down
towards them.

Kapitan Schwalbe hurried to the conning-tower.  The object depicted was
that of a modern tank-vessel about four hundred feet in length.  She
was low in the water, showing that she was well laden.  In place of
masts she had four stumpy poles supporting derricks.  Right aft was the
single funnel.  The navigation bridge was well for'ard, connected with
another bridge just in front of the funnel by a long slender gangway.

"An oil-tank homeward bound!" exclaimed Kapitan Schwalbe.  "Just what
we want to fall in with.  All being well, there will be no necessity to
visit either Port Treherne or St. Mena's Island.  Ach!  When we have
taken what we require we will set fire to the ship, and the English
will have a splendid view of a maritime bonfire."

The crew were ordered to their stations, the ballast tanks "blown", and
U75 rose to the surface instead of "running awash", since the Kapitan
had resolved to stop the tank by gun-fire.

Even then the waves were running so high that the guns' crews were
almost constantly up to their knees in water.

Somewhat to the surprise of the submarine's officers and crew, the
tank-steamer made no attempt to escape.  The firing of a shot across
her bows and the display of the black cross ensign were enough to cause
the skipper to reverse her engines.

In less than five minutes, the oil-vessel was rolling in the trough of
the sea and drifting slowly to leeward.  Yet it was a somewhat
remarkable circumstance that no attempt was made to lower the red
ensign that was proudly displayed at the stern.

Kapitan Schwalbe, with his intimate knowledge of navigation, knew that
the only way possible to board the prize was to run to leeward of her,
and let the hull of the large vessel serve as a breakwater.  He also
knew that the submarine would have to be constantly under way during
the boarding operations, otherwise the tank-vessel, offering
considerable resistance to the wind, would drift down upon U75, whose
leeway was almost unappreciable.

"Send a boat, and lower your accommodation ladder," ordered Kapitan
Schwalbe, who, as the submarine ranged up half a cable's length to
leeward of the tank-vessel, had left the shelter of the conning-tower
and was standing on the platform in its wake.

"Aye, aye," was the prompt response.

"Board her, Herr Rix," said the Leutnant's superior officer.  "Bring
back her papers with you.  Order them to pump heavy oil both to
windward and leeward.  We will then be able to run close alongside and
receive her hoses."

A boat containing two seamen and an apprentice was lowered from the
tank's quarter and rowed to the submarine.  Into it dropped Leutnant
Rix and half a dozen armed men.  With them they took two incendiary
bombs fitted with time-fuses.

Rix smiled grimly as he gained the oil-steamer's deck.  The captain and
first mate were at the head of the accommodation ladder to receive him.
Most of the crew were already mustering on deck, each with a bundle
containing his private effects.

"You prize to German boat," announced the Leutnant.  "Make you no
trouble and we you will not harm.  First we will haf much
oil--petroleum, is it not?  Order your engineer to get steam to
donkey-engine, and your men--the--the----  Hein!  Ach, I haf it--the
hoses to get ready.  When we fill up, then twenty minutes we give you
to clear out.  You onderstan'?"

"Perfectly," replied the British skipper, a tall, raw-boned Scot, as he
eyed the podgy German Leutnant with grim contempt.  "But d'ye ken yon?"

[Illustration: "'D'YE KEN YON?' ASKED THE BRITISH SKIPPER, AS HE EYED
THE PODGY GERMAN LEUTNANT WITH CONTEMPT"]

He pointed skywards.  Less than five hundred feet up, yet sufficiently
far from the tank-vessel to enable the latter to screen her from the
unterseeboot, was a large naval sea-plane.  It was to deaden the noise
of her motors that the ship's steam-pipe was continually blowing off
steam from the time that U75 made her peremptory demand.

The eyes of the Leutnant and his six men followed the direction
indicated by the British skipper's outstretched hand.

At that instant the sea-plane was visible above the towering sides of
the British vessel.

U75 was still forging slowly ahead.  In a trice Kapitan Schwalbe
decided how to act.  Ordering the men on deck to their diving stations,
he dropped agilely into the conning-tower and gave the word for the
helm to be ported.

Thus, while the quick-firers were being housed, the submarine had drawn
close under the oil-tank's quarter.  Here she was comparatively safe
from the sea-plane, as the latter could not drop any bombs without risk
of exploding the highly inflammable cargo of the British vessel.

In ten seconds the sea-plane was over and beyond her quarry.  She had
then to turn and circle overhead, awaiting the chance of shattering her
enemy as she dived.

U75 was already disappearing beneath the waves.

She dived at a very oblique angle, steeper than she had ever done
before.

Ross and Vernon, unaware of what was taking place, thought for a moment
that the submarine was plunging headlong to the bed of the Bristol
Channel.  They had to cling desperately to the nearest object to hand
to prevent themselves from sliding violently against a transverse
bulkhead.

Even as they clung they heard two muffled detonations in quick
succession, followed by a distinct quiver of the submarine's hull--a
movement that bore a marked difference to the vibrations under the
pulsations of the motors.

The sea-plane had dropped two bombs, both of which very nearly attained
their object.

Kapitan Schwalbe did not bring the submarine to a horizontal position
until she had reached a depth of fifteen fathoms.  At that depth he was
safe, both from explosives dropped from the sea-plane and also from
observation.  The water being still agitated, made it impossible for
the observer on the biplane to follow the movements of a dark shadow
fathoms deep.  For once, the rough seas had been kind to U75; but the
fact remained that she was still badly in want of fuel, while his last
attempt had resulted in the loss of an officer and six men, who could
not well be spared.

Although the sea-plane had failed to achieve her object by pulverizing
the U-boat's hull, the moral and material result was none the less
effective.

The explosion of the bombs had started several of U75's plates.
Numerous jets of water were spurting through the seams, the inrush
requiring all the mechanical appliances at the command of the modern
pirate to keep the leaks under control, while the badly-jarred nerves
of Kapitan Schwalbe and his crew warned them of the grave risks they
ran in attempting to try conclusions with even an apparently harmless
craft displaying the Red Ensign of Britain's Mercantile Marine.

CHAPTER IX

The Landing at Port Treherne

"I wonder if they'll let us go on deck," remarked Vernon Haye.  "If so,
I vote we have a shot at getting ashore.  What sort of show is Port
Treherne?"

"I know it fairly well," replied Ross.  "It's the most forsaken crib
you are ever likely to meet along the coast.  It's a deep gully in the
cliffs.  There's only one small landing-place--a flat rock.  Years ago
there used to be a tramway down to the rock, and they shipped copper
ore by means of derricks into lighters, which were towed across in fine
weather to Swansea.  But the mine closed down, the village is now
deserted, and I don't believe there are any fishermen there.  They say
that the stream that flows into the port is still heavily charged with
mundic.  At all events the water is of a bright-red colour for several
hundred yards from shore, and no fish will stick that."

It was close on the midnight following the disastrous attempt on the
part of U75 to capture the oil-tank.  The submarine was running awash,
proceeding very slowly and cautiously towards Port Treherne--Station 41
of the secret petrol depots established by German agents along the
coast of the British Islands.

The lads had been informed of the destination of the submarine, but had
not been told why.  Nevertheless it was an easy conjecture that U75 was
going there to pick up stores that she had been unable to obtain in
sufficient quantities at St. Mena's Island.

The Unter-leutnant was in charge of the submarine.  Kapitan Schwalbe
had taken the advantage of the opportunity of a few hours' sleep.
Under-officered and undermanned, the strain on the personnel was a
severe one.  It was only on rare occasions that Schwalbe could in
future descend from his post in the conning-tower.

At midnight, according to custom, the submarine called up her consorts
by wireless.  Judging by the previous attempt it seemed a useless task,
but to the Operator's surprise he received a reply from U77, which was
then lying off the Scillies.

Kapitan Schwalbe, aroused from his sleep, eagerly awaited the decoding
of the message.  It was to the effect that the commander of U77 had
received information that H.M.S. _Tremendous_, one of the earlier
Dreadnoughts, was leaving Gibraltar for Rosyth.  The _Tremendous_, he
knew, had been engaged in the Dardanelles operations.  U77 therefore
suggested that the two unterseebooten should meet at a rendezvous off
The Lizard, and attempt a _coup de main_, the success of which would go
towards atoning for the blunders and losses sustained by the German
submarines in their endeavour to blockade the British Isles.

"Good!" exclaimed Kapitan Schwalbe.  "Tell them that I purpose to
rendezvous twenty kilometres S.W. by W. of The Lizard, on Thursday at
10 p.m.  I am now about to take in fuel.  Will communicate again at
noon to-morrow.  Ask them if they have picked up a wireless from U74."

Some time elapsed before the message could be coded by the sender and
translated by the receiving submarine.  When the reply confirming the
rendezvous was received, a message was added to the effect that U77 had
heard nothing of U74 for three days.  It was presumed, however, that
she was now on her way back to Wilhelmshaven, and was already out of
wireless range.

Kapitan Schwalbe knew better.  As senior officer of the three
submarines detached to operate in these waters, he was aware that U74
would not have left her station without orders from him.  That part of
the message had been sent merely as a "blind", so that the crews of the
remaining unterseebooten should not be discouraged.  It was safe to
conclude, decided Kapitan Schwalbe, that another of the blockaders had
gone to the bottom for the last time.

It was close on one o'clock when the "wirelessing" terminated.  U75,
which had hitherto been running awash, was now trimmed for surface work.

Most of the crew went on deck.  Amongst them were Ross and Vernon, no
one offering any objection.

The sea was no longer rough.  A long oily swell took the place of the
white-crested wave.  The night was dark.  Only a few stars were
visible.  Away to the S.E., the black outlines of the Cornish coast
reared themselves like an enormous wall against the gloomy sky.

Suddenly Vernon touched his chum's elbow, as a faint pin-prick of light
glimmered twice.  It was the shore agent's signal that the coast was
clear.

Barely carrying steerage-way, U75 stood in towards the as yet invisible
Port Treherne.  Already her crew had brought the collapsible canvas
boat from below, "man-handling" it through the fore hatch.  The men,
having opened it out and shipped the felt-lined and well-greased
rowlocks, stood by to launch it.

Gradually the towering cliffs enclosing the creek became
distinguishable against the loftier background of gaunt hills.  Into
the gap the submarine crept with the utmost caution, until it seemed as
if she were on the point of running her nose against the sheer face of
the granite wall.  The water bubbled slightly as her motors were
reversed; then, turning in her own length, she brought up, with her
bows pointing seawards.

Three of the crew grasped the canvas boat and pushed it gently into the
water on the port side.  One of them clambered in and shipped the oars
in the row-locks.

The two lads were cautiously scanning the shores of the inlet.  Ross
could sniff the unmistakable Cornish air.  The call of home seemed
irresistible.  It looked a comparatively easy matter to slip quietly
over the starboard side, and swim with noiseless strokes towards the
weed-covered rocks that showed six feet or more above the sea.  It was
half ebb-tide; there was little or no drift out of the cove.  Under the
shadow of those dark cliffs detection seemed almost impossible, unless
the submarine went to the risky expedient of switching on her
search-light.

They moved stealthily towards the light wire railing on the starboard
side just abaft the conning-tower.  Everything seemed in their favour.
Kapitan Schwalbe and the Unter-leutnant were on the navigation
platform, peering through their night-glasses towards the flat rock
that served as a landing-place.  Two of the seamen were engaged in
coiling down a hand-lead line; the rest of the men on deck were
devoting their attention to the now departing canvas boat.

"Not so fast, my friends," exclaimed a low deep voice, which the lads
recognized as that of Kapitan Schwalbe.  "Remember I have a pistol
ready to hand."

"How in the name of goodness did he know what we were up to?" thought
Ross.

The chums stood stock-still.  They felt much like children found out in
some petty escapade.

"Koppe!  Where are you?" asked the Kapitan in a loud whisper.

"Here, sir," replied the seaman.

"I hold you responsible for these Englishmen.  Now they are trying to
give us the slip.  Take them below.  But hold on.  Secure them to a
stanchion.  Chain them up, and bring me the key."

The seaman approached the lads almost apologetically, and led them to
the port side just for'ard of the conning-tower.  A light steel chain
was hitched round Ross's right ankle and Vernon's left, and deftly
padlocked round one of the uprights supporting the hand-rail.

"It is of no use trying any of your pranks here," commented Kapitan
Schwalbe, still in a low tone.  "You are only looking for trouble."

For several moments all was still, save for the screech of a benighted
gull.  Overhead a meteor passed swiftly across the sky, throwing a pale
gleam upon-the lurking submarine.

"Wer da?"

The words, although uttered in an undertone, travelled distinctly over
the placid waters of the cove.

The sailor in the boat muttered some inaudible reply.  The listeners in
the submarine could detect the sound of his oars as he laid them across
the thwarts.  Then, after further conversation, could be heard the
rumble of metal as the tins of petrol were rapidly placed in the boat.

"How many are there?" asked Kapitan Schwalbe eagerly as the men
returned with the first load.

"Forty here, Herr Kapitan.  Altogether there are over two hundred."

"Then be sharp and whip them on board.  Was there any communication for
me?"

"A bundle of English newspapers, sir, and this letter."

The man drew the documents from the inside of his jumper and passed
them to a seaman, who in turn handed them to the skipper.

"I may have to land, sir," continued the seaman.  "The rest of the cans
are in a cove at some distance from the landing-place.  Can Max go with
me to mind the boat?  There is a slight ground-swell at times, and she
might have a hole through her canvas if she is allowed to grind against
the rocks."

Receiving an affirmative reply, the man told his comrade to get on
board, and once more the boat vanished into the darkness.

Another twenty minutes elapsed, then came the sounds of muffled
footsteps, and of volatile spirit surging inside the petrol cans.  Then
one of the men must have slipped, for there was a slight scuffling,
followed by the loud crash of a can clattering over the rocks.

"'Alt!  Who goes there?" shouted a hoarse and unmistakably English
voice.

"Freund," promptly replied the German sailor.

It would have been far wiser on his part if he had waited for his
fellow-worker, the German agent, to reply, since his knowledge and
pronunciation of English were almost perfect.  But unfortunately it was
the spy who had fallen, and, half-winded by coming in contact with one
of the tins, was gasping for breath and at the same time rubbing a
barked shin.

"Not good enough for me, old sport," rejoined the challenger, and
without further ado he let loose "five rounds rapid".

A loud yell announced that one of the bullets had at least taken
effect.  It was the prostrate spy who received a dose of nickel through
the fleshy part of his thigh.

The seaman, dropping his cans, fled for his life.  Recklessly he leapt
from the landing-place into the canvas boat, which his comrade had been
keeping at oar's length from the shore.  The sudden impetus was too
much for the frail craft.  She capsized, and, being only
single-skinned, sank like a stone.

Already men, members of a picket, were hastening to the sentry's
support, their progress marked by a lantern held by a stout and sleepy
sergeant.

By this time U75 was making for the open sea.  Kapitan Schwalbe was
cursing loudly; not because the luckless agent had been hit--it was his
fault for not making sure of his ground; not so much on account of the
loss of two more men, nor of the sinking of the only boat belonging to
the submarine.  His anger was aroused at the knowledge that once again
his efforts to obtain fuel had been balked.  The quantity contained in
forty tins was a mere fraction of the amount he required in order to
carry out his ambitious programme.  Bitterly he realized that, like
those of transgressors, the ways of modern pirates are hard.

CHAPTER X

A Treacherous Plot

A ragged volley of musketry followed the departing submarine.  One
bullet mushroomed itself against the steel conning-tower; another
zipped through one of the guard-rails.  The rest either flew harmlessly
overhead or ricochetted from the surface of the placid water.

Nevertheless the firing was a signal for the crew to hasten below.
Kapitan Schwalbe and the Unter-leutnant disappeared with ignominious
speed within the conning-tower.  The men, bending low, bolted for the
fore hatch.  In twenty seconds the deck of U75 was deserted save for
Ross and Vernon, who, padlocked to the stanchion, were unable to move
six inches in either direction.  They were only partly screened by the
rise of the conning-tower.  A sharp splinter from the bullet that had
splayed against the steel wall cut cleanly through Vernon's coat sleeve
and inflicted a slight gash in the lad's forearm, yet in the excitement
he hardly noticed it.

"I say, old man," exclaimed Ross, as a wave slapping against the
submarine's bow threw a shower of spray over the two prisoners.  "What
will happen if they submerge?  It seems to me as if old Schwalbe has
forgotten us."

"He would have dived before this if he intended so doing," replied
Haye.  "Ten to one he's going to pay us out for attempting to take
French, or rather German, leave.  It's jolly cold and mighty
uncomfortable, but we'll keep a stiff upper lip and show him what we
are made of."

"With all due deference to you, old chap," rejoined Trefusis, his teeth
chattering as the keen wind played upon his saturated garments, "I
would far rather be without this badge of German kultur."  He indicated
the chain that encircled his ankle.  "I don't think that you can hold a
brief for Kapitan Schwalbe.  I am not so sure about it that he is not
going to dive."

U75 dipped as he spoke, submerging her fore deck almost to the base of
the conning-tower.  Then, with a double cascade of water pouring from
her, she shook herself free, throwing her bows high above the surface.

A man, gripping the stanchion-rail as he made his way knee-deep in
water, came towards the two prisoners.  It was Hans Koppe.  He had
obtained the Kapitan's permission to release his charges from their
uncomfortable position.

"Hold on tightly as you go aft," he cautioned.  "There is hot coffee
waiting for you below."

It was impracticable to descend by means of the fore hatch.  That means
of communication had already been closed and battened down, owing to
the constant flow of water over the bows.  Even the after hatch, in
spite of the protection afforded by the conning-tower and the raised
coaming, was admitting water into the interior of the submarine.

Cold, exhausted, and hungry, the lads were glad to be able to eat and
drink, discard their wringing-wet garments, and turn in.  Without
waking they slept solidly for ten hours.  It was one in the afternoon
when they turned out.  U75 was rounding Land's End.  She was submerged,
steering a compass course, but frequently showing her periscope to
ascertain her whereabouts.  Already the Longships Lighthouse was broad
on the port beam.

It was a tedious, discomforting run from Land's End to The Lizard.  The