Geoffrey Falconer removed the wireless telephone receivers from his ears, and sat back in his wooden chair, staring straight before him, utterly puzzled.

“Eighteen-and-a-half minutes past seven!” he muttered to himself, glancing up at the big round clock above the long bench upon which a number of complicated-looking wireless instruments were set out.

In front of him were half-a-dozen square mahogany boxes with tops of ebonite and circles of brass studs, with white circular dials and black knobs and a panel of ebonite with four big electric globes for wireless transmission. Across the table ran many red, white, and green wires from a perfect maze of brass terminal screws, while in one oblong box there burned brightly seven little tube-shaped electric glow-lamps, the valves of the latest instrument which amplified the most feeble signals coming in from space from every part of the western world. It was the newest wireless device for the reception of weak signals and he himself had made an improvement upon it, a new microphone amplifier which was at present his own secret.

“Eighteen-and-a-half minutes past seven!” he repeated. “Always at the same moment that strange signal is repeated three times. And not Morse—certainly not in the Morse code. It’s a most mysterious note,” he went on, speaking to himself. “Others must surely hear it—or else my amplifier is so ultra-sensitive that I alone am able to listen.”He took from near his elbow a long scribbling-diary, and glancing through its pages, noted various entries concerning that mysterious signal which never failed to come each evening at eighteen-and-a-half minutes past seven.

That small private experimental laboratory in the ground floor room of a spacious country house on the brow of a low hill in Essex was well fitted with all kinds of apparatus for wireless telephony, telegraphy, and the newest invention of direction-finding for the guidance of aircraft in darkness or fog.

The tall, clean-shaven, dark-eyed young man, whose hair was brushed back, and whose bearing was distinctly military, had done excellent service in the wireless department of the Royal Air Force, and had won his Military Cross. Before the war, at the age of nineteen, he had been a persevering amateur, keenly interested in the mysteries of wireless. His knowledge thus gained, with crystal receivers and “spark” transmitters, stood him in good stead; hence, during the war, he had held a number of responsible appointments connected with aircraft wireless.

After demobilisation he had at once taken his degree in Science, and then joined the research department of the great Marconi organisation, in which he was showing excellent promise. Quiet and unassuming, he possessed for his age unusual technical and mathematical knowledge, and great things were being predicted of him by his superiors at Marconi House. Already he had made certain improvements in the application of the telephone to wireless, together with small adjustments and the use of condensers in certain circuits, technicalities which need not be referred to here because only the expert could follow their importance. Suffice it to say that Geoffrey Falconer’s whole heart was in his work. Though he did wireless all day in the great well-lit laboratory at the Chelmsford works, he nevertheless spent most of his evenings at his own private wireless station at his father’s house at Warley, about a mile from Brentwood, which was about ten miles from Chelmsford and twenty from London.

Old Professor Falconer’s house, a Georgian one, half-covered with ivy and surrounded by several giant cedars, stood well back from the broad high road which runs from Brentwood Station through Great Warley Street to Upminster. Those who pass it will see a double-fronted house approached by a curved drive half-hidden from the road by a high yew hedge. The big gates of wrought iron are as ancient as the house, which, built in the days of George the First, still retains its old-world atmosphere of the times when dandified neighbours in wigs and patches were borne along the drive in their sedans to visit old Squire Falconer and his wife.

Outwardly the house is the reverse of artistic, but within it is a charming old place, with oak floors and panelled walls, a great well staircase leading from the wide square hall, while the furniture is even to-day mostly in keeping with its restful atmosphere.

The Falconers have lived at Westfield Manor ever since its construction. Its present owner, John Falconer, had been a famous Professor of Science at Oxford, until he retired and returned to Warley to enjoy the evening of his days, while his son Geoffrey, who had been brought up in an atmosphere of science, and who followed closely the footsteps of his distinguished father, now lived with him on being demobilised.

By the elastic licence granted to him as an experimenter by the General Post Office Geoffrey had been allowed to erect high twin aerial wires double the length of the official regulation of one hundred feet, and these, suspended from poles placed in the tops of two of the high Wellingtonias, were brought across the wide lawn to the rear of the house, and down into the room in which the young man was seated.

“Always the same long drawn-out note at exactly the same time!” he went on. “Eleven-and-a-half minutes before ‘F.L.’ sends his weather report. What, I wonder, can it mean?”

From the Eiffel Tower, whose call-letters in the radio-telegraphic code are “F.L.,” weather reports from western Europe are each evening sent out upon so powerful a note that they are read on the opposite side of the Atlantic. Young Falconer, therefore, fell to wondering whether those strange signals he heard nightly, and which were so unaccountable, were not in some way connected with the transmission from Paris.

The eleven-and-a-half minutes passed, and just as the Eiffel Tower began to call in that peculiar cock-crowing note which all wireless men know so well, his father entered.

“Hulloa, Geoff! I thought you had gone up to town—it’s Mrs. Beverley’s dance, is it not?”

“Yes,” replied the young radio-engineer; “but I’ve just been listening. I’ve tuned in that same strange signal as last night. It is really most curious.”

“Automatic transmission, perhaps,” replied the alert, white-bearded old gentlemen. “Did you not say that there were some transmissions at a hundred words a minute in progress?”

“Yes, Witham and Farnborough. But I have heard them many times during the past few weeks. I know the note of Farnborough. Besides, his wave-length is different. This mysterious signal is on eleven hundred mÈtres—a continuous wave—above the ships and the Air Ministry.”

“And nobody else hears it except yourself?” asked the lean, deep-eyed old man, who possessed such wide scientific knowledge, though he admitted that wireless was a branch with which he was not familiar. Radio-telegraphy was a new science, fresh discoveries being made daily by those who, like his son, were engaged in active research work.

“Not so far as I can learn. I’ve asked our people at Poldhu, Carnarvon, and Witham, and I’ve listened myself at Chelmsford, but nobody hears it.”“Your improved amplifier—without a doubt!” his father said, bending over the long oblong metal case in which the seven little lights were burning in vacuum tubes about three inches long, and set in a row. Attached to the amplifier was a double note-magnifier, and an oblong wooden box—the invention of Geoffrey Falconer.

“Perhaps,” said the young man, whose well-cut, impelling countenance wore a puzzled look. “But I can’t see any reason why I should be able to detect signals which are lost to others,” he added. “I know I’ve got excellent rectification, but not more than the ordinary type of ‘fifty-five amplifier.’ It is only the amplification that is higher.”

“Well, the signals are certainly a mystery,” agreed the Professor. “When I listened to it last night it seemed like a high winter wind howling through a crack in a door or window.”

“To you it might. But, you see, I’ve developed the wireless ear, and sounds that you pass, I recognise.”

“Of course, my boy,” the old gentleman said. “You live for wireless, just as I now live to complete my great book. We must both persevere in our own spheres. I am only glad that the war is over, and now that your poor mother is, alas! dead, you have returned to keep me company in my loneliness,” and the old man sighed at the remembrance of his dear, devoted wife, who had died two years before.

“Well, the old place could not be handier for me—close to Chelmsford. Besides, away here I can continue my research work each night without disturbance.”

“That’s so. But, surely, you recollect accepting the invitation Mrs. Beverley so kindly sent us? We really ought to go,” his father urged. “It isn’t too late—even now.”

Geoffrey smiled within himself.

“Right-o! I suppose we ought,” he replied. “Let’s dress at once. I’ll take you to the station in the side-car, and we can get a hasty bit of dinner at the club before we go along to Upper Brook Street.”Then he turned down the big aerial switch which sent the incoming currents to earth and acted as a protection to his instruments against either lightning or “strays.” And closing the door of the room, he went to put on evening clothes.

When Professor Falconer and his son entered Mrs. Beverley’s fine house in Upper Brook Street it was nearly half-past nine. As the door opened there came the strains of an orchestra. Mrs. Beverley was the widow of a wealthy banker of Buenos Ayres, after whose death she had brought her daughter Sylvia to London where she had quickly become popular as a hostess, attracting about her all sorts of men and women who had “done something.”

When one was invited to Mrs. Beverley’s parties one was certain of meeting interesting people—lions of the moment—whose faces peered out at one from all the picture papers—people in every walk of life, but all distinguished, if even by their vices.

“Hulloa, Geoffrey!” exclaimed a slim, dark-haired young girl in a flame-coloured dance-frock and a charming hair ornament of gilt leaves. The dress was sleeveless and cut daringly low in the corsage and the back. “I thought you’d forgotten us!”

“Well, Sylvia, I’ll confess,” said Geoffrey in a low voice, taking the hand she held out to him. “As a matter of fact, I really had! The pater only reminded me of it just in time for us to rush to the station.”

“Ah! Immersed as usual in your mysterious old wireless,” laughed the pretty daughter of the South American widow. “I heard somebody say at a lunch at the Ritz the other day that all electrical people inevitably take to drink or to wireless.”

“Well, I’m glad I haven’t yet taken to the former,” laughed the young man, and together they went into the fine drawing-room, where a gay dance was in progress.

A few moments later the young man found his hostess, a stout, well-dressed woman, who possessed all the impelling manners of the well-bred South American, and who had hustled into Society until the newspapers were constantly chronicling her doings, describing her jewels, and printing her photograph, so that Suburbia knew more of Mrs. Beverley than even Mrs. Beverley knew herself. She loved Argentina, she confessed, but she loved London far better. Before her marriage she had known quite a lot of people in London society, for she had come over each year, and now, in her widowhood, she had returned, and certainly she was one of London’s prominent figures, for she entertained Cabinet Ministers, politicians, authors, painters—in fact, anybody who was anybody in London life.

Geoffrey had first met her and her daughter while on the voyage from New York eighteen months before. He had been over on business to the transatlantic Wireless Station at Belmar—which, by the way, is in direct communication with Carnarvon by day and night—and on board they had been introduced, with the result that the widow had invited him to call upon her “when she settled down.”

The pretty go-ahead Sylvia had attracted him, and when one day he had received a card at the Automobile Club he lost no time in resuming the very pleasant acquaintanceship. Indeed, Mrs. Beverley and Sylvia had motored down to Warley one day a month afterwards, and looked in at Geoffrey’s experimental laboratory, bewildered at its maze of instruments, its many little glow-lamps and tangles of wire.

Mother and daughter had listened upon the relay and “loud-speaker” of the wireless telephone to the Air Ministry at Croydon, Pulham, and Lympe, and to the Morse signals from Newfoundland, Cairo, Madrid, and other cities, until the girl, with whom he was secretly in love, had declared herself quite fascinated by the most modern of sciences.

Indeed, it was this fascination which had first held the two young people in a common bond. On board the liner, though as an engineer of the Marconi Company he was constantly in and out of the wireless cabin because the operator was having some trouble with his spark transmission, it had never occurred to him to invite the girl in to listen. It was, indeed, not until a few hours before they reached Southampton that he had explained his profession to her.

The pair had, on the voyage, fallen very much in love with each other, and now, thoroughly understanding each other, they were carefully preserving their secret from Mrs. Beverley, whose great ambition, like that of many South American mothers, was to marry her daughter into the British Peerage.

As a matter of fact, the real object of her lavish entertaining at Upper Brook Street was to find a suitable husband for Sylvia, a peer of wealth, no matter his age or past record.

In Geoffrey Falconer, Sylvia had found a clever, good-looking, unassuming man, whose ideals coincided with her own, even though she naturally viewed England and English ways through South American spectacles. Yet for three years she had been at school at Versailles, and mixing with English girls as she had done, she had lost much of her American intonation of speech.

The pair were genuinely attached to each other. The only third person who knew of this was the old Professor himself. Though thin and white-haired he was a genial old fellow, who dearly loved a joke, and who, when at Oxford, had been regarded by all the undergraduates as a real good sort. Many of his students had made their name in the world of politics and law, while one was now Governor of one of Britain’s most important colonies.

Like father, like son. Geoffrey, though he had for four years been associated with those young men of the Air Force who, though so many of them had never flown a yard, considered themselves vastly superior to all others who trod the earth, had never imitated the “wrist-watch swank,” nor the drawl of that grey-uniformed genus who, during the war, brought personal egotism to such a fine art. He was quiet, unassuming, studious, yet a firm-hearted, bold, and fearless Englishman.Sylvia, thanks to her mother’s sly machinations, met numbers of eligible young men, many of whom had great fortunes looming in the future. But in the whirl of London society, with its dressing, dancing and dressmakers’ lure, she passed them all by, her only thought being of the young man whom she had met on board the liner.

That night they had danced together several times, when suddenly, as they crossed the ballroom, the girl exclaimed:

“Look! Why there’s Mr. Glover! You surely recollect him? He came over with us. I thought he was in Paris.”

Falconer glanced across to a big, broad-shouldered, round-faced man, who was clean-shaven, with a lock of fair hair falling across his forehead, a man with protruding chin, thick lips, a pair of shrewd blue eyes, who wore an emerald in his shirt-front.

In an instant a crowd of memories flashed across her companion’s mind. For a second he hesitated. Then he advanced, and greeted his fellow-traveller across the Atlantic.

“It was awfully kind of your mother to ask me, Miss Beverley,” said the big, burly fellow to Sylvia as they shook hands. “I took a house near Maidenhead, but I’ve been in Paris ever since we got over. I only got to the Ritz three days ago, and received her card through Morgan’s.”

“Well, we’re awfully pleased to see you,” Sylvia declared. “We’ve at last settled in London, and it’s real good to be here.”

“Yes,” drawled Mr. George Glover. “I usually come over to Europe twice a year on business, and I always look forward to it. Americans who haven’t travelled never realise the delights of dear old London, do they?”

Presently the trio went in to supper together. Quite casually Sylvia mentioned Geoffrey’s connection with wireless, whereupon Glover began to discuss some of the newest theories in a manner unusually intelligent for the uninitiated. This caused Geoffrey’s thoughts to wander far from that gay crowd by which he was surrounded.

The man seated opposite him was something of a mystery. On the trip over to Europe, at one o’clock one morning, he had despatched from the ship a curious wireless message. Geoffrey had happened to be in the cabin with the chief wireless operator when the message had been brought in. He was assisting the operator to adjust his spark, which was slightly out of order. Ships’ wireless sets, like watches, are sometimes liable to vagaries. Why, nobody can tell.

The message sent in was marked “very urgent,” but the “spark” was poor, and the range at the moment rather inefficient. As it lay beside the transmitting key, Geoffrey read it.

He remembered it quite distinctly because, by some strange intuition, he felt that it was not what it pretended to be. One sometimes experiences strange suspicions. And in this case Geoffrey wondered. He knew the sender, and perhaps because of his friendship with Sylvia and her mother, he had felt a little irritation, for he instinctively mistrusted the man.

The message was of a commercial character, and read:

“Betser, King’s Arms Hotel, Norwich.—Don’t deal directly demand delay execute slowly.—Glover.”

Next day he had found himself reflecting upon that message, and returning to the wireless cabin, he copied it. For a whole day he puzzled over it, when at last—used as he was to all sorts of ciphers and codes—he discovered in it a four-figure code. The initial letter of the first five words was “D”—the fourth letter of the alphabet. Then “E”—the fifth letter—and “S”—the nineteenth. Hence the message was no doubt in figure-code, and read “4519.”

From that moment onward he had viewed the man Glover with considerable suspicion, but on landing at Southampton he had lost sight of him. And now he was much surprised to find him as guest of the rich widow.

Sight of the thick-set, clean-shaven man had brought that strange message back to his memory, and the more so because on deck late one night he had seen the man talking in confidence to a stout, flashily-dressed woman, yet next day they had passed each other on deck as strangers!

As the trio sat at supper, Glover was most genial and full of merriment. That Sylvia liked him was plain, yet whether it was intuition or jealousy, Geoffrey, as later on he sat with his father in the last train from Liverpool Street, pondered again and again.

On his return from Chelmsford each evening during the week that followed, Falconer sat down at a quarter past seven at his own wireless set, when, without fail, there came that strange, inexplicable and unreadable signal always at eighteen-and-a-half minutes past seven.

Of operators at the great Marconi stations at Towyn, in Wales, and Clifden, in Ireland, as well as of several operators whom he knew at the busy coast stations at the North Foreland, Niton, and Cleethorpes, he made inquiry as to whether they had heard the same signal. Strangely enough, all the replies were in the negative.

Indeed, one night he himself listened on the great aerial which is such a prominent feature in the landscape at Chelmsford, but failed to catch a single sound.

Therefore, he proved beyond doubt that his own set was supersensitive, and that his improvement of the multi-valve amplifying detector was a considerable achievement.

He, however, said nothing. At present it was his own secret. But he was not so much concerned with the new invention as in the solution of the mystery. By his research work in the wide field of radio-telegraphy he had developed a keen interest in anything that was mysterious, and here was presented an extremely curious problem. That oblong metal box with its seven little glowing glass tubes was the only instrument which picked up that inexplicable signal.

A fortnight passed. Each anxious day young Falconer worked hard in the splendidly-equipped experimental laboratory in that hive of wireless industry at Chelmsford, where radio apparatus of all kinds was being constructed for every civilised nation—that triumph of the Italian inventor who gave to the world a means of instant and reliable communication unknown before those epoch-making experiments on Monte Nero, outside the sun-blanched town of Leghorn. Truly the science of radio-telegraphy has made rapid strides since the days of the “coherer,” until now, after the war, it is the most advanced in our human civilisation, and at the same time full of romance. Not a month passes but something new is discovered in that high-built, well-knit laboratory, where daily the keenest brains of wireless experimenters are at work devising, testing, and too often scrapping new instruments, new circuits, and new devices in order to improve and render less complicated both the ordinary wireless by Morse, and that modern marvel, the wireless telephone.

The world has yet to learn what it owes to wireless. Little does it dream of its aid to commerce in every quarter of the globe; how much of the news it reads at its breakfast-table had been flashed through the ether for thousands of miles, or how every hour it outstrips the choked-up and behind-the-times submarine cable system.

Geoffrey Falconer was very sorely puzzled.

But why was that mysterious signal unheard by others? Further, by what method was it being transmitted? Being acquainted with every method of transmission, he guessed, after a number of tests, that it must be automatic. One day he took his improved microphone amplifier to the works at Chelmsford, and attaching it to the very complicated apparatus designed for the reception of signals automatically transmitted—a piece of apparatus far too technical to here describe—he sat at a quarter past seven awaiting the usual signal.With him were two of the research staff, both as deeply interested in the mystery as himself, though upon their high-up aerial wires they had been unable to detect the signals in question.

“Hulloa!” cried Boyd, a fair, clean-shaven man of thirty-five, who was a well-known radio-engineer. “There she goes!”

The receiving apparatus gave a short quick buzz, thrice repeated, and then there was silence again.

Eagerly Falconer took the record which had been made, and placing it in another small box, adjusted the head-’phones, and depressing a key, allowed it to revolve slowly. The message became distinctly readable!

They were figures—the numerals 4519, thrice repeated. It was that same code-message which the genial Glover had sent from the liner in mid-Atlantic! What could it mean?

Two facts were now proved—that the amplifier, as improved by Geoffrey, was a supersensitive instrument, which would, no doubt, have a great future before it, and bring its inventor both money and fame in the world of radio-telegraphy. Secondly, that some curious mystery lay behind the appearance of Mr. George Glover in London society.

That night on arrival home, he told the Professor of his discovery, and both father and son agreed that it was necessary to make some searching investigations regarding Mrs. Beverley’s friend.

With that object Geoffrey went up to London on the following day, and calling upon Sylvia fortunately found her alone.

With difficulty he approached the subject of Glover, because he knew that the girl suspected him of jealousy. She had, indeed, hinted at it on the night of the dance. However, in the course of conversation, he casually referred to the man who had despatched that curious telegram from the liner.

“Oh, yes!” the girl answered. “We see quite a lot of Mr. Glover now. Mother likes him immensely. He is enormously rich—has great oil interests in Roumania and in Baku. He made a great deal of money during the war, and he knows quite a number of good people in London. He’s going down to Lady Nassington’s, in Sussex, next week—and we are going too.”

“You will be fellow-guests then?” Falconer remarked.

“Yes, Geoffrey. But you speak as though you resent it,” laughed the pretty girl.

“Not at all,” he hastened to assure her. “Only——”

“Only—what?” she asked.

“Well—nothing,” he replied. “At least, nothing at present.”

“You’re awfully mysterious, Geoffrey. What do you really mean?”

“Nothing,” he declared. “What should I mean? I hardly know your friend, Mr. Glover. Your mother, no doubt, knows him well.”

“Yes—and all about him,” the girl replied. “He’s awfully kind to us. He took us to Brighton in his big car last Sunday week, and gave us a topping time there. He claims to be a American but I don’t know if he is.”

Geoffrey reflected. That strange series of secret signals held him mystified. So he determined to wait and watch.

Next day, when in the experimental laboratory at Chelmsford, he took his friend, Frank Boyd, into his confidence regarding the signal they had tuned in, and also told him of the message sent by Glover late one night from mid-Atlantic.

Boyd, who stood with the head-’phones in his hand, for he had been making a test upon a new direction-finding device, listened with great interest.

“I agree, Falconer, there’s something wrong somewhere,” he remarked. “But who can have a transmitting-set which sends out messages upon a wave-length that we can’t get?”

“It may be by the new beam method,” Falconer suggested, “the method with which we are just now experimenting. Once or twice I’ve thought it might be a military continuous-wave set.”

“If so—then they are in front of us. That, however, I very much doubt,” declared Boyd. “The Germans thought themselves top-dogs in wireless before the war, but we beat them every time on their own ground—didn’t we?”

“We certainly did. Here, in these works, the inventions were made and developed for the Army, Navy, and Air Force. It’s up to us—to you and me personally—to solve this mystery.”

“Yes, Falconer—and we’ll do it,” said the other. “I don’t like the idea of signals being sent out that we can’t read from our big aerial here.”

“They are signals from nowhere, yet always the same, and at exactly the same time. G.M.T. never alters—neither does the signal,” Falconer said.

So the pair agreed to listen still further, and to make investigation regarding the wealthy man from America, who had so suddenly arisen in the social firmament of post-war London.

Geoffrey had some few days’ leave due to him, so he took it, and, unknown to Mrs. Beverley and her daughter, watched the gay house-party assemble at Nassington Hall, the seat of the Earl of Nassington, not far from Crowborough, in Sussex.

Now, near Crowborough there was a wireless station, and on the night of Geoffrey’s arrival at the Beacon Hotel, he called upon the non-commissioned officer in charge, introduced himself, and was afforded an opportunity of looking over the apparatus. Naturally the man in charge was gratified that such an expert as Geoffrey Falconer should examine their set, and pronounce both transmission and reception unusually good. Then, soon after ten o’clock, Geoffrey returned to the Beacon.

That night he sent a note in secret to Sylvia, and in the autumn afternoon next day they met at the junction of the two roads at Marden’s Hill.“I’m down here to have a look at a wireless set close by,” he explained. “Isn’t it fortunate? I’ll be here for a couple of days, I expect.”

“You gave me a real surprise,” the girl said. “When Thring brought me your note with my morning tea I could hardly believe that you were so close at hand. Why not come in to tea? Mother will introduce you to Lady Nassington.”

“No,” he replied. “I have, unfortunately, a lot of work to do at the wireless station. Please excuse me.”

“Ah! I know. You don’t want to meet Mr. Glover,” laughed the girl. “Now confess it!”

“It isn’t that, I assure you, Sylvia. But I would rather have a walk and a chat with you than gossip with all those people with whom I have so very little in common.”

“Yes, Geoffrey, I know. You are engrossed in your wireless inventions,” she replied, gazing affectionately into his eyes. “And, after all, you are right. We women enjoy ourselves, but men who serve the world as you do are nobler if they keep away from all our feminine frivolities.”

“I suppose Glover is merry, as usual—quite a good fellow, isn’t he?”

“Yes. He’s the soul of the house-party. They are all out shooting to-day. Madame Valdavia, the wife of the Spanish millionaire banker, arrived last night. She’s quite young and charming. I wish you could meet her.”

“I can’t. I’m sorry.”

“You can if you will only call on mother to-morrow.”

“But I’m really too busy, Sylvia—so do please excuse me,” he pleaded, as they walked along the leaf-strewn path through the wood from Friar’s Gate, where half a mile away towards Lone Oak the shooting party were giving evidence of good sport.

“We have a fancy dress dinner to-night. Every one is wearing quaint costumes, and there’s certain to be a lot of fun. The party is really most enjoyable. I do wish you would call, Geoffrey—do,” she urged.“No,” said the young man very seriously. “I have reasons which I will tell you afterwards.”

“You are always so mysterious,” she declared with a pretty pout. “I believe it is your horrible old wireless which makes you so.”

“No, not horrible,” he protested with a laugh. “Interesting, I admit—in more senses than one.”

“Well—interesting, then,” she agreed with a nod of her pretty head. “But I can’t see why you are so very interested in Mr. Glover. Every one at Lady Nassington’s likes him.”

“So do I, Sylvia.”

“Then why be so mysterious?”

“I’m not mysterious. I happened to have come down to see the wireless installation here, and you are staying at a country house in the vicinity. So I just looked you up—that’s all.”

“But why don’t you call? I want to introduce you to them all.”

“And if I called to see you, your friend Glover, knowing of our friendship, would, in the smoking-room, whisper that I had followed you down here. No. I prefer that we should preserve our secret, Sylvia. You surely don’t want to cause your mother annoyance and anxiety? Remember you are to marry a man of title. At the very thought of your being engaged to me your mother would faint.”

“Yes,” laughed the girl, dashing aside some dead leaves with her walking stick. “I really think she would.”

“Then, for the present, let us remain quite quiet,” urged young Falconer. “I will see you again when you get back to town.”

A few moments later, while they stood on the path beneath the leafless trees, the young man raised her gloved hand to his lips, and then they parted, she to hurry on and rejoin the guns, and he to return to Crowborough.

Falconer was there with a distinct purpose. He walked back to the Beacon Hotel, ate his dinner, and played billiards until half-past ten o’clock, when he put on his coat and went out for a moonlight walk. He pictured to himself the gay scene at Nassington Hall, which he might easily have joined, yet he hesitated because of the problem he had in hand.

The white moon shone brightly over the Sussex downs as he walked along the high road to where the wireless station was installed.

He called there and had another chat with the sergeant on duty. Then he resumed his walk in the direction of Nassington Hall.

When within a hundred yards of a side gate which gave entrance to a short cut from the hall to the railway station, he drew back under a huge thorn-bush and lit a cigarette.

He wondered whether he was not making a fool of himself. From where he stood he could see in the distance the many lighted windows of the Hall. No doubt, scenes of merriment were taking place within.

The clock of Crowborough Church chimed the hour of one—half-past—then two o’clock. The distant windows were still lit, and finding a fallen tree, he sat down to contemplate.

Soon after two o’clock the lights in the distant windows died away, one after another. The fun was over. The wind blew cold, and even in his thick overcoat he shivered. Yet when he was putting a theory to the test in wireless or otherwise, he never begrudged sleepless hours.

Just after four in the morning, while he still remained patiently at his post, Geoffrey’s quick ear suddenly heard the sound of approaching footsteps. Drawing back, he watched a dark figure coming hurriedly from the direction of the Hall, until, when it passed close by him, he saw in the dull half-light that it was a middle-aged countryman, evidently a local farmer who was up and about betimes.

In chagrin he drew back into his place of concealment, but a few seconds after the man had passed a fresh thought suddenly occurred to him. So, noiselessly, he followed the passer-by in the direction of the station. The man, however, did not go to the railway, but at a short distance from it he drew back into a hedge, in order, no doubt, to wait for the first train in the morning.

Geoffrey watched for a further half-hour, then withdrew and hastened to the wireless station, whence he called up a friend of his named Hemmington, who lived in Hampstead, and had an amateur wireless station there.

He had not repeated the amateur’s call-signal three times before he received an answering signal, after which his hand rapidly tapped the keys. Then a few seconds later he received the signal, “O.K.”

Afterwards he returned to the Beacon Hotel, arriving there just as the sleepy servants were astir.

He breakfasted early, but scarcely had he finished when he was called by the waiter to the telephone.

It was Sylvia who spoke. In a state of greatest agitation she told him that burglars had broken into the Hall in the early hours and had stolen her mother’s rope of pearls, worth over twenty thousand pounds, and also nearly the whole of Madame Valdavia’s fine jewels, which she had worn at the fancy dress dinner.

“We are all horrified, Geoffrey,” she went on. “Mr. Glover has just gone out in the car to tell the police. What can we do? Can you come up here? Mother wants to see you.”

“I’m awfully sorry,” was Falconer’s reply. “Please excuse me, as I’m terribly busy to-day. But tell your mother, in strict secrecy, that I have a notion that she will get her pearls back again.”

“What do you mean, Geoffrey?” asked the girl’s high-pitched voice.

“What I’ve said, Sylvia. Remain patient. I have to go up to town at once. I’ll telephone you again at two o’clock this afternoon. To-morrow I shall not be so busy on wireless, and I’ll run down and see you all—and also meet Mr. Glover,” he added with a laugh.

“But—but——”He only laughed, and put up the receiver.

The truth was that, owing to Geoffrey’s message to the wireless amateur in Hampstead, the bucolic-looking individual from Crowborough had been detained by the police when he had stepped out of the early train at Victoria, and upon him there had been found the whole of the stolen property.

Owing to what Geoffrey was able to disclose to the Criminal Investigation Department, a very curious state of things became revealed.

It was found that the genial George Glover—who, by the way, was promptly arrested and subsequently extradited to Paris—was none other than the notorious Henry Harberson, head of a great gang of International crooks and jewel thieves, who had recently established their temporary headquarters in London, and who had as receiver an old Dutchman at Utrecht named Van Hoover.

Thanks to Falconer’s patient investigations, extending over a further period of some weeks, it was also rendered clear that Harberson had, with the latest refinement of criminality, actually established wireless communication with each of the six members of his gang in England, by means of a very ingenious transmitter, the signals of which were unreadable save under certain conditions. A man named Jensen of Copenhagen had devised it, and that mysterious signal of four numerals had been sent out daily just before half-past seven in order to inform each member all was safe, and that no police inquiry was being made.

The jewels had been stolen from Nassington Hall by the pretended wealthy man, whose oil interests in Roumania were bogus, and handed out of the conservatory window to a confederate from New Orleans named Blades, who was dressed for the occasion as a Sussex farmer.

Both men, with two of their accomplices, who were found in possession of secret receiving sets, were sent over to France, and at the time of writing they are all serving long terms of imprisonment for three sensational jewel robberies committed there.

Mrs. Beverley was, however, naturally delighted to be again in possession of her pearls, while in Geoffrey Falconer’s private laboratory there is to-day Harberson’s very up-to-date secret wireless set which the police seized at the pretty house which, as George Glover, he rented on the Thames, not far from Maidenhead. In construction it is, after all, only a variation upon a set previously devised in the research department at Chelmsford, yet there are two factors in it which, to Geoffrey, established a new theory, and which, as will later on be apparent, were destined to be of distinct advantage to him in his experiments and investigations into the romance of wireless.