"Absolutely certain," said Crouch. "I don't imagine for a moment that the old woman's in league with a gang of German spies; else she would never have shown us up here. For all that, she's not to be trusted further than a first engineer can throw a quoit. That's all the better for us. I don't suppose she'll come back to-night."

"And what about these men, Russell and Valentine?" asked Jimmy. "Who are they, do you think?"

"Valentine may be any one," answered Crouch. "But I've a shrewd suspicion that Russell is Rudolf Stork. Stork has now been in England three days. He has had plenty of time in which to get to London."

"And if he turns up," asked the boy, "what are we to do?"

"If it's necessary, shoot him like a dog," said Crouch, forgetting that he was not on his ship's deck.

For the next half-hour, they systematically searched the whole flat, but could find nothing suspicious. There was an aspect of newness about the place; carpets, curtains, and cushions had evidently come straight from the furnishers, and showed no signs of wear. In an old-fashioned Sheraton bureau were writing and blotting paper, ink and pens; but, the blotting paper was quite spotless, and the pen nibs had never been dipped into the ink.

"There's nothing here," said Crouch. "We shall have to wait for Stork."

And hardly had the words left his lips than a bell rang, somewhere in the room. Jimmy started, and even Crouch carried a hand to the coat pocket that contained his revolver. The moment was one of intense excitement; they were face to face with great events. It was as if the atmosphere of the room was electrified by the strong current of anticipation.

"The telephone!" cried Jimmy, pointing to the wall.

In a moment, Crouch had the receiver to his ear. He had the wisdom not to speak, until he had found out who it was who had rung up the unoccupied flat, and this proved to be no less a person than the mysterious "Mr. Valentine," who was speaking from the "Hotel Magnificent" in the Strand. "Are you there?" he asked. "Are you the charwoman?"

Crouch replied at once, in the old woman's squeaky voice.

"I'm Mrs. Wycherley," said he.

"I told you," said the voice, "that you were to expect Mr. Russell this evening. He will probably arrive at about eight o'clock."

"Very well, sir," said Crouch. "The rooms is aired, and all the fires was a-lighted this morning, and everything's that clean you could eat your dinner off the carpet, as sure as my Emily Jane's blood has turned to water."

"Shut up!" cried "Valentine," so loudly that even Jimmy was able to hear. "I've not rung up to hear about Emily Jane. I intended to come round this evening, to meet Mr. Russell on his arrival; but I have to go to Edinburgh at once, on extremely urgent business, and have only just time to catch my train. Can you hear what I say?"

"Bless you, yes, sir," answered Crouch. "It don't make no difference whether it's the butcher or a hundred-weight o' coal, I allus makes use of the telegraph, and I don't take no sauce from the young woman in the middle."

"Then, listen here," said "Valentine." "I'm sending round a messenger-boy with an important sealed letter. On no account whatever are you to let this letter out of your hands, until you give it to Mr. Russell, the very moment he arrives."

"Valentine," in order to make quite sure that Mrs. Wycherley had heard aright and understood, made Crouch repeat his instructions word for word. That done he rang off, apparently in the greatest haste, no doubt fearing to miss his train.

Captain Crouch was wildly excited. Jamming his white bowler hat well on to the back of his head, he proclaimed that they were hot upon the scent of the gang. Mrs. Wycherley had left him in possession of the key of the flat; and going down to the front door, he waited impatiently for the messenger to arrive.

The messenger-boy had some diffidence about handing over the letter to Crouch, saying that he understood that he was to deliver it to a charwoman. Crouch, however, was not to be denied, and with the sealed letter in his hand returned to Jimmy.

To break the seal and tear open the envelope was the work of a few seconds. The letter was written in German, of which language Crouch and Jimmy knew enough to make out the meaning, though there were one or two words that neither could understand. With the translation of "Valentine's" letter all doubt was dispelled that the unknown "Mr. Russell" was any one else than Rudolf Stork, the ship's carpenter of the "Harlech."

The letter began with the words "Dear Stork," and continued to the following effect: A sea raid had been planned on the North Coast, against the dockyards of the Forth and Tyne. All German submarines had been warned, with the exception of the U93, whose wireless had been probably by H.M. Destroyer "Cockroach." The U93 had come north-eastward from the Lizard, had passed the Straits of Dover in safety, and was now lying somewhere in the vicinity of the Wellbank lightship, which is a little north of the latitude of the Tyne.

Immediately on his arrival in London, Stork was to go to Hull, taking the first and fastest train. Thence, he was to put to sea in a fishing smack, the "Marigold," the skipper of which was in the pay of "Valentine." He was to find the U93, and tell her to proceed due east without delay, to meet the German fleet, issuing from the Bight of Heligoland, and which would comprise some of the biggest battle-cruisers ever built: notably, the "Derfflinger," the "Seydlitz," the "Blücher," and the "Moltke."

Captain Crouch was a man of iron nerve; but, when he realized the colossal magnitude of the plot with which they were confronted, even he could not control the features of his face. As for Jimmy Burke, his lips were parted, and when he held the letter in his hand, the sheet of paper trembled like a leaf. Scene by scene, the great drama that had opened in the offices of Rosencrantz and Guildenstern unfolded itself before the eyes of those who were something more than mere spectators. And each scene, it appeared, was more dramatic, more fraught with terrible consequences and possibilities of triumph or disaster, than that which had gone before.

It took Jimmy Burke some time to find his breath. He was so excited that he found it difficult to speak.

"There's not a moment to lose!" he cried. "We must report what we know both to the Admiralty and Scotland Yard."

"We can't leave this place," said Crouch. "Stork may turn up at any minute; it must be nearly eight o'clock already. I'll ring up the Yard, at once."

He went straight to the telephone, where almost immediately he got into communication with the famous headquarters of the London Police. He was informed that a superintendent-detective would be sent at once to Number 758, Edgware Road.

Crouch placed the receiver back upon its rest, and pulled out his watch.

"It's past eight o'clock," said he. "Russell should be here."

It was at that very moment that they heard the sound of footsteps upon the stone staircase without. Crouch hurried to the door and threw it open; and there entered three men, two of whom were young, whilst the other was considerably over sixty.

Both Crouch and Jimmy scanned the face of each man as he entered, and both, with their hands in their pockets, grasped the handles of their revolvers. In spite of the intense excitement of the moment, Jimmy Burke was conscious of a feeling of bitter disappointment, when he saw that not one of these three men was Rudolf Stork.

Each of the two younger men was well over six feet in height, broad of shoulder and deep of chest. They were dressed precisely the same, and wore blue suits, light-coloured overcoats, brown boots and wide-brimmed, black felt hats. As for the older man, he had the appearance of a professor, or some sage of ancient times; there was something about him that might almost be described as druidical. His hair was quite white, very long and somewhat greasy. He had a white beard that reached almost to his waist. His nose was long and aquiline, and his eyes much magnified by a pair of gold-rimmed spectacles. In his hand he carried an ash-plant, so knotted and heavy at the head that it resembled a club. It was he who was the first to speak, staring at Crouch over the top of his spectacles.

"Pardon me," he observed, in a voice that was exceedingly soft; "pardon me, but I have not the pleasure."

"Nor I," said Captain Crouch.

"I think you must have made a mistake," the old man went on. "My name is Russell-Theophilus Russell-and this flat belongs to me."

"Then," said Crouch, "there must certainly be some mistake. My name is Shakespeare-Melchisedek Shakespeare-and this flat happens to belong to me."

Mr. Russell adjusted his spectacles upon his nose, and looked around the room.

"There should be a woman here," said he; "a Mrs. Wycherley."

"She's gone out," said Crouch.

The old man smiled and pointed with his stick.

"Why, there she is!" he exclaimed. "How strange that I never noticed her before."

He had pointed to the armchair, at the other end of the room, in which Crouch had formerly been seated. The whole thing was so cleverly planned, the old man's voice was so dulcet and confiding, and his expression of surprise so admirably feigned, that Crouch could not resist the wholly natural impulse of turning round, to see for himself whether or not Mrs. Wycherley were there.

His eyes had not left the old man's face for longer than the fraction of a second before there took place a kind of transfiguration which was even more terrible to see than it was surprising.

There had been something about the patriarchal figure of the old, white-bearded man that was gentle, beneficent and charitable. His expression had been that of one who looks upon the world, and all its fooleries and foibles, with the comfortable tolerance of age. On a sudden, this expression changed. His eyes flashed; his brows became knit in a savage frown. At the same time, this transformation extended to his body, which straightened, quivered, and even seemed to grow larger. Before it was possible to guess what he was about to do, or make the slightest movement by way of self-defence, he had raised his heavy ash-plant high above his shoulder, and brought it down with a crashing blow upon the head of Captain Crouch.

The little sea-captain had been taken unawares. Once again had he been fooled. He let out a groan, spun round like a top, and then came down heavily upon the floor.

In so short a space of time did this calamity occur that Jimmy Burke had barely time to act. He had taken two steps forward, and had got so far as drawing his revolver from his pocket, when he was seized and held fast in the powerful arms of the two younger men. Before he had time to cry out, or even to realize what had happened, he found himself not only with a gag thrust into his mouth, but with both hands handcuffed behind his back.

Russell laughed aloud, in a voice that was far from dulcet.

"I saw through your disguise," he cried, pointing to the prostrate figure of the little captain, "the very moment I entered the room. Something more is needed than a white bowler hat and a scarlet necktie to conceal the identity of Captain Crouch."

At that, Crouch struggled to his feet, and stood for a second swaying. Then, with a loud cry and a kind of lurch forward, he flung himself like a wild-cat upon the old man, whom he seized roughly by the throat.

"You villain!" he shouted at the full power of his lungs.

So great was his passion, so amazing his agility, that there is little doubt he would have strangled the old villain then and there, had it not been for the two younger men, who hurled themselves upon his back.

They dragged him away as though he had been a mad dog, but not until he had seized Russell by his long, flowing beard, which he tore, not piecemeal, but bodily, in a mass, from the old man's wrinkled face.

A moment later, Crouch, like Jimmy Burke, stood handcuffed. Panting, literally foaming at the mouth, he glared at his assailant. And as he glared, it was as if his single eye grew larger in his head. His thin lips parted, though not a word escaped him; it was as if amazement had struck him dumb.

The truth was, he found himself confronted by the most surprising part of an incident which, from start to finish, was at once unlooked-for and bewildering. For, the old man, bereft of his spectacles and beard, stood before Crouch discovered and confessed; and in place of the grey and patriarchal features of the so-called "Mr. Russell" was the seamed and weather-beaten countenance of Rudolf Stork.

CHAPTER XIX-A Clue

It may seem surprising that our good friend Captain Crouch (who was very far from a fool) should have been gulled so successfully, and on no less than two occasions, by Rudolf Stork. It must not be forgotten, however, that Stork had been an actor, who knew well not only how to disguise himself, but how to change his voice, and the expression of his face, and to assume those habits and little mannerisms by which personality is made evident. He not only looked the part of an old dry-as-dust professor, but acted up to it so cleverly that both Crouch and Jimmy Burke were quite deceived.

When he found himself overpowered and handcuffed, when he saw how completely he had been duped, Captain Crouch could not conceal his rage and mortification. He shouted at the full power of his lungs, in a vain hope that some one would hear and hasten to his help, forgetful for the moment that the building was utterly deserted, that Mrs. Wycherley was not likely to return.

In any case, Rudolf Stork was not the man to run unnecessary risks; his case was altogether desperate. To silence Crouch by means of a gag, accompanied by a vicious kick in the ribs, was a task of not much difficulty, nor one that took longer than a minute at the most.

Stork then rose to his full height, and placing both arms akimbo, looked down upon his victims, who lay side by side upon the floor.

"If I had killed you out of hand," said he, "you'd have nothing but your own cleverness to blame. You should have learnt by now to let sleeping dogs lie. Let me tell you this, Captain Crouch, as one sailor to another: you set foot on dangerous ground the moment you thought fit to interfere with me."

Going down upon a knee, he turned out their pockets, finding first the keys which Crouch had obtained from Mrs. Wycherley, and then the brace of revolvers that they had purchased that very morning.

"You came prepared, I see," he grumbled. "It's just as well I thought to disguise myself, or, like as not, I should have been shot on sight."

And then, in the inner pocket of Crouch's coat, he discovered the letter written by "Valentine" in German, which had come in a sealed envelope from the "Hotel Magnificent." Without a word, he read it to the end, and then, folding it carefully, put it away in a letter-case which he kept in a hip-pocket along with a jack-knife large enough to cut a loaf of bread.

"The fat's in the fire," said he, turning to his companions; "there's no doubt as to that. These fellows know more than is good for them. We must put them out of the way. It's a nasty business, but war's war, and those who employ me don't stick at trifles, such as the life of a tramp skipper and a stowaway."

At that, one of the younger men lifted a hand-a quick, nervous gesture, denoting at once surprise and consternation.

"Kill them!" he exclaimed.

"There's no other way," said Rudolf Stork.

"I don't like it," said the other.

The third man now spoke for the first time. "It would be madness," said he, "and a cold-blooded business as well. We can leave them here, handcuffed, gagged, and with their feet bound tightly."

"There's the old woman," said Stork. "She'll find them for a certainty before twelve hours are past. For myself, I take no risks."

"I'll not be a party to it," said the man who had spoken first.

"Then you're a fool," cried Stork. "You fail to realize the gravity of the business. A raid has been planned on the North Sea coast, and these two know all about it. In any case, the raid will take place, there's no time now to stop it; and if the British Admiralty is warned, the result will be disastrous. Whatever happens, the lips of these two men must be closed, for five days at least." Then on a sudden, he changed his voice and slapped a hand upon his thigh. "I've got it!" he exclaimed. "Valentine purchased the whole of this building, on behalf of the German Secret Service, in order that we should have no eavesdroppers in the way of next-door neighbours. I've got the keys here. We'll lock them both up in one of the empty flats, the one on the top floor for choice. There, they'll be well out of the way, and as good as dead."

This idea commended itself to both the younger men. It was eminently safe, and presented not the least difficulty. Also, it had the advantage of evading the terrible responsibilities of wilful murder.

Accordingly, the two captives were carried up to the top storey of the building, where, after their legs had been tightly bound, they were locked up in an empty room. Here not even Mrs. Wycherley would find them. From the amount of dust upon the floor and windows, and the innumerable cobwebs suspended from the ceiling, it was evident that no one had entered the flat since the very day upon which the last tenant had left it. Even had Crouch and Jimmy not been gagged, and had they shouted till they were hoarse, they could never have made themselves heard. Neither was there any possible means of escape. They were shut up in a room which had once been used as a bedroom, and the hall door of the flat was locked from the outer side. The only window-which was quite small-looked out upon the roofs and chimney-pots of the adjacent houses several feet below.

Since Stork and his companions could afford to waste no time, the whole of this dastardly business was carried out quickly and in silence. And in less than ten minutes after the suggestion had been made, Crouch and Jimmy Burke were left alone, listening to the receding footsteps of the German spy and his confederates growing fainter and fainter as the three men descended flight after flight of stairs.

The thoughts of a man who finds himself in such a situation cannot be of the pleasantest. What Crouch's were, no one is ever likely to know, since-for very shame, perhaps-he ever afterwards kept them to himself. As for Jimmy Burke, he felt then, and quite believed, that from the very days of his boyhood, his life, and every enterprise he had ever undertaken, was doomed to failure. So far, nothing had gone well with him; and now that his fortunes were bound up with those of Captain Crouch, it seemed that he was to lead even the little sea-captain-hitherto so masterful-along the straight and certain path to unmerited disaster.

There are moments in the lives of us all when despondency obscures our outlook upon life, in much the same manner as a thunder-cloud darkens a summer sky. And yet, we should learn that Hope can remain with us to the last. We can no more foresee the actions of other men that influence our own lives-often indirectly-than we can foretell the dispensations of Providence itself. Always, we are in God's hands; it behoves us to act like men, and put our trust in Him.

It is possible to become so hopeless that we deliberately turn our backs upon the brighter side of things; and this is what goes by the name of pessimism. And now Jimmy Burke, giving himself up for lost, was quite unable to remember that there still existed a very great possibility that both he and Captain Crouch would be discovered.

Indeed, not more than ten minutes had elapsed after Stork had taken his departure, when suddenly the whole house was made to echo with a dull, thudding sound, as if some one were banging on a door. This noise continued without ceasing for at least five minutes. It appeared to proceed from the lower part of the building. At first, the boy could not think what it was; and then, on a sudden, like a bright flash of light in the midst of all the gloom of his despondency, he remembered that Crouch had rung up Scotland Yard, and that in all probability it was the police themselves who were below.

Apparently the same thought occurred to Crouch, for the little captain made a sudden and desperate effort to free himself; and presently, by some means or other, he managed to stagger to his feet, only to fall once more prostrate to the ground.

For all that, he was not one to admit that he had failed so easily. He got to his feet again, stumbled across the room and threw all his weight upon the door.

Captain Crouch was neither tall nor heavily built; he could not have weighed more than nine stone; and, naturally enough, he failed to break open the lock-even if that had been his intention. He fell to the ground a second time, bruised and out of breath; but there was a possibility that the noise had been heard by those who were within the building.

For some seconds they waited in suspense, listening intently, silent and quite helpless. And then, they heard footsteps on the stairs, and the sound of voices, and some one trying the doors.

Crouch got to his feet again. He could not cry out because of the gag that was still fastened in his mouth. He had no other means of making his whereabouts known than the method he had tried before. Again he threw his weight upon the door and fell heavily to the ground.

This time there could be no doubt that he had succeeded in his purpose. A man came to the outer door of the flat, tried to open it and failed, and then called out in a loud voice, asking who was within.

Neither Crouch nor Jimmy could answer. It must also be remembered that the room in which they were imprisoned was quite dark, save for the fact that a full moon had arisen which had cast upon the floor a square pattern criss-crossed by the shadows of the framework of the window. Since the flat was quite unfurnished and the walls of the passages were bare, human voices were magnified in sound, and it was possible to hear quite distinctly what was said by those outside the door. The voice of one man was particularly distinct. Not only was it louder than the others, but its tones were authoritative; it was he who gave orders to those who were with him. As they guessed from the very first, this was Superintendent-detective Etheridge-a man whose reputation in his own line of business was second to none.

"Go on, man!" he exclaimed. "Break the door down. There's no time to waste trying to force the lock."

There was a dull thudding sound, as the full weight of a six-foot London policeman was hurled against the door.

"Try again," said the detective; "and this time all four of us together."

There was a pause, during which, no doubt, the detective and his companions gathered themselves together; and then, as one man, they threw themselves forward, so that four heavy shoulders struck the door a single blow.

The combined weight of these men could not have been less than fifty-four stone, at the very lowest estimate; and that is a shock that a modern spruce-wood doorway was never constructed to stand. Not only was the lock broken open, so that the woodwork of the jamb was splintered for at least a foot, but the hinges were wrenched bodily away. The outer door flung back with a crash, and a second later the detective and his men found themselves in the passage of the flat.

"Which room is it?" cried Etheridge. "Where are you?" he shouted at the full power of his lungs.

Crouch could not answer by word of mouth, but he could do just as well. Sitting as upright as he could, he spun round like a top, so that his two heels rapped out upon the door. Then he rolled over and over, until he had gained the security of the centre of the room.

It was Etheridge who spoke again.

"Here!" he cried. "This room! All together, as before!"

The inner door was forced even more easily than the first. As it fell inwards, and four burly figures burst into the room, both Crouch and Jimmy were blinded by the sudden glare of three policemen's lanterns. A moment later the gags were taken from their mouths, and they were free to speak.

"Who are you?" asked the detective, assisting the little sea-captain to his feet and unlocking his handcuffs.

"I'm the man who rang you up," said Crouch. "The rascals left here not twenty minutes ago. Had you come sooner, you would have bagged all three of them. As it is, there's no knowing where they've gone, nor whether we'll ever see them again."

There were a hundred things the detective wished to know. As yet he had been told nothing, beyond the fact that Captain Crouch had certain information in regard to a gang of spies. Together they went down to the first-floor flat, where they turned on the electric light, and where Crouch answered the detective's questions, telling his whole story in instalments, so to speak.

They had not a copy of the mysterious message which Jimmy Burke had found on board the "Harlech"; but this made no difference, since both Crouch and Jimmy knew it by heart. In order to explain to the detective how they had discovered the address in the Edgware Road, Jimmy went to the writing-table, and taking pen and ink, wrote out the message.

They explained to the detective how they had discovered the concealed address in the first and last letters of every word; and then they were able to see something of the peculiar workings of a great detective's mind.

In this world, there is reason in all things-even in those things which may seem most trivial and unimportant. The criminal investigator must not be satisfied with facts; it is his business to find out the why and wherefore of everything that comes in his way. Moreover, he must be observant; he can afford to miss nothing. As often as not, a clue is to be found in the most improbable place.

Superintendent-detective Etheridge had no sooner read the message a second time than he laid hold upon a clue.

"This message," said he, waving the paper in his hand, "was written by a man who does not know London well."

"How's that?" said Crouch. "As far as I can see, there's no way of telling who wrote it. It was picked up on board the ship that I commanded, that by all the laws of chance and methods of modern warfare should have been sent sky-high, to be no more than a ton or so of floating wreckage."

The detective preferred to hold to his own opinion; and it must be confessed that that opinion was likely to be right.

"It was written," he repeated, "by a man who does not know London well. Otherwise, he would have been able to spell 'Edgware Road.'"

Etheridge had now spread the paper upon the table, and both Crouch and Jimmy were gazing over his shoulder, whilst the three plain-clothes policemen stood together in the doorway.

"Edgware Road," the detective went on, "does not happen to be spelt with an 'e.' This cypher was evidently concocted by a man who-if not an Englishman himself-was well able to write-and, in all probability, speak-the English language. He was not, however, personally acquainted with London. For myself, in view of what you have told me, I should say that it was written by one of the German gang you discovered in New York."

"I have it!" cried the boy. "When I overheard the conversation that took place in Rosencrantz's office, I remember that von Essling himself said that, though he was well acquainted with the English language, he had never been to London, but expected to go there shortly."

Etheridge, who had produced a large note-book from his pocket in which he was scribbling a few hasty lines, closed it with a snap.

"That settles it," said he. "The Baron von Essling and this 'Mr. Valentine' who lives at the 'Hotel Magnificent' are one and the same person. I've no doubt of it whatever."

"What proof have you of that?" asked Captain Crouch.

"No proof," said the detective. "I set to work on bare suspicion, and leave proof to the last. In this case my suspicions are well founded. A few days before war was declared, a man, passing himself off as 'Lewis Valentine,' landed at Liverpool, having crossed from New York on the 'Olympic.' He is known to have stayed at the 'Hotel Magnificent,' and is supposed to have remained in London about three weeks. Afterwards, evidence was forthcoming to the effect that he was one of the Prussian military attachés in the United States, who was engaged upon Secret Service work. Two days ago rumours reached me that this man was once again in England; and the very reason I was late here to-night is that I was first obliged to go to the 'Magnificent,' where I learned that Valentine had left not an hour before. Take my word for it, this fellow is von Essling."

"And he has gone to Edinburgh?" asked Jimmy.

"Not a bit of it!" said Etheridge. "It is no more likely he would tell a charwoman his destination than his real name and business. He has gone to Liverpool; and that's all the more probable since the 'Baltic' sails early to-morrow morning."

"Thunder!" cried Crouch. "This is a greater game than big-game shooting in the Sunderbunds. I never in my life picked up a spoor like this."

"One thing's a certainty," said Etheridge; "I leave for Liverpool without delay. There's no fast train till morning; but I can get there in an eighty horse-power car. But, first, you must both come with me to the Admiralty. Jarvis," he added, turning to one of the policemen, "don't forget to drop into the White Star offices to-morrow morning, and tell them there's no fear this voyage that the 'Baltic' will be torpedoed."