Mrs. Beverley was giving one of her usual dinner-parties at Upper Brook Street. Among the guests were two Cabinet Ministers and their wives, for money can always command guests, the names of whom will be duly recorded in the society column of the Morning Post next day.

Money buys publicity, and without the latter nowadays one may as well live in suburbia, or in the peace of a country village.

When the hostess and her guests went to the drawing-room, Geoffrey—who had just come back from making some adjustments at the wireless station at Renfrew—managed to snatch a quarter of an hour with Sylvia in the cosy little sitting-room next to the library.

The young engineer had been telling her of his work up in Scotland, and of a pleasant Saturday he had spent up Loch Lomond, when the girl suddenly asked:

“How do you like Mrs. Mapleton, whom you took into dinner?”

“Oh, very nice,” he replied. “I suppose she’s a new friend of your mother?”

“No. We met her and her husband a year ago when we were at HyÈres. They live near Madrid, and have asked us to go and stay with them for a month at their villa outside the city. Mother has accepted. Didn’t I hear you say that you might be sent out on business to Madrid?”

“Yes. There was some mention of it the other day,” Geoffrey replied. “They were having trouble with their valve-panel at the wireless station at Aranjuez, which belongs to the Compania NaÇional, and I heard that it was proposed that I should go out to see what I can make of it.”“How splendid if we are in Madrid together—eh?” exclaimed the girl enthusiastically. “I do hope we shall manage it. The Mapletons go back in six weeks’ time, and we go with them. He’s an English banker in Madrid.”

Just at that moment one of the guests entered the room, so the lovers were forced to return to the drawing-room, where a little later Geoffrey found himself talking to the rather handsome young woman who had sat beside him at dinner. She was dark, with a very clear complexion and great black eyes, a graceful figure, and a sweet and winning smile. Her husband, to whom she introduced him, was some ten years her senior, a tall, rather spare man with an aquiline face somewhat bronzed by the southern sun.

They chatted together, whereupon Mrs. Mapleton mentioned that Mrs. Beverley and her daughter were travelling with them to Madrid. Then Geoffrey remarked that he would, in all probability, be in the Spanish capital at the same time, and explained the reason of his journey.

“Well, if you are in Madrid, Mr. Falconer, you won’t fail to come and see us—will you?” urged the lady. “We live out at El Pardo—only half an hour from Madrid.”

Geoffrey thanked her, and promised that if he went to Spain he would certainly call upon her.

Two months later he found himself at the old-fashioned HÔtel de Pastor at Aranjuez, which is thirty miles from the capital, and not far from the great wireless station. After remaining there two days making his preliminary investigations of the work he had in hand, he one day took train to Madrid, and went out in a taxi along the terribly dusty road to El Pardo.

He found the house without any difficulty—a great country mansion in the Spanish style—surrounded by beautiful grounds. The door was opened by an elderly English butler, who showed him in and took his card at once to his mistress. In a few seconds Sylvia, who had been eagerly watching her lover’s arrival, rushed forward and greeted him warmly, while almost at the same moment their hostess appeared and gladly welcomed the young fellow.

It was just before luncheon, so Geoffrey, after being shown the glorious gardens and the views, was compelled to remain, and sat down with Mrs. Mapleton, her husband, the South American widow, and Sylvia. The meal was served with considerable pomp by the butler, Martin, the whole staff of servants being English. Mrs. Mapleton, when Martin was out of the room, remarked that she had become tired of the slovenly ways of Spanish servants, and therefore she had engaged English ones, all of them having been in service with English families in France or Italy.

“Martin is, of course, our mainstay,” she added. “He speaks Spanish well, which is a great thing, as we naturally have many Spanish visitors.”

“Yes,” said Mr. Mapleton; “Martin is a real treasure for a busy man like myself. He was in the service of the Marquis de Borja, secretary to Queen Marie Christine, and only left after his master’s death.”

“Then you are very lucky to get him,” remarked Mrs. Beverley. “I know what it is to have a butler upon whom one can rely. A widow like myself is very handicapped in that respect. I am no judge of wine. I leave it all to my man, and I trust him implicitly.”

“Just as we trust Martin,” said the banker’s good-looking wife, and then the entrance of the sedate and respectful servant put an end to further discussion.

Luncheon over, Mrs. Mapleton proposed a run in the car over to El Escorial, the favourite summer resort of the MadrileÑos, where they visited the wonderful Royal Monastery of San Lorenzo del Escorial, the huge pile of whitish granite, destitute of ornament, and broken by small windows; one of the most remarkable edifices of all time which seems to rise out of the stony sides of the great Guadarrama Mountains, and resembles, except in its majestic faÇade, a fortress or a prison.

“How wonderful!” exclaimed Sylvia, as they were conducted into the magnificent church built on the model of the original plan of St. Peter’s in Rome, with its forty-eight altars, each containing a valuable painting, its magnificent frescoes, and the immense high altar of valuable marbles and exquisitely gilded bronzes, before which many candles were burning. They were shown the Sacristia, the PanteÉn de los Reyes, or burial vault of the Spanish monarchs, the Library, and afterwards the Royal Palace.

Later they motored back along a road below which, in the gorgeous Spanish sunset, lay the plain of New Castile and Madrid on the one hand, and the Guadarrama Mountains on the other.

Next evening Geoffrey again returned to El Pardo, and as he stood with Sylvia and Mrs. Mapleton upon the terrace of the villa, the banker’s wife pointed across to a towering rock upon the edge of the mountains.

“Over there is the Crow’s Cliff,” she said. “From it, through many centuries, those guilty of murder were hurled. Indeed, even during the past few years battered bodies of men and women have been found beneath it, victims of those who have taken justice into their own hands.”

“How horrible!” exclaimed the smart young South American girl. “When was the last body found?”

“About a year ago—a labourer in a vineyard close by, on going to work one morning, found the body of a well-dressed young woman. She was believed to be English by her clothes, but she was never identified. The police have abandoned their inquiries, as it is a complete mystery.”

“She was purposely pushed over the Cliff, I suppose?” remarked Geoffrey.

“Perhaps,” replied his hostess. “But it is believed that there have been cases where the guilty have been condemned and executed by their fellows in order to suppress any scandal. More than one person moving in the highest circles has been found dead beneath the Crow’s Cliff.”

“Couldn’t we go up there and see it?” suggested Geoffrey.“Certainly you could,” she replied. “There is a good road, though rather hilly, and a path which takes you close to the edge of the Cliff.”

So all three went to see the Crow’s Cliff.

The road proved badly kept and shadeless, as are most of the roads in Spain, and the path was rocky and crooked as they ascended to the summit of the PeÑa Grajera—the Crow’s Cliff.

At last all three walked to the edge of the precipice, where through the ages so many of the guilty ones had been hurled to destruction.

“That story about the young Englishwoman haunts me!” Geoffrey said to Sylvia as they approached the place and peered down upon the river winding across the plain below, which stretched away into the evening mist. “I wonder who she was?”

“Nobody will ever know,” declared Mrs. Mapleton. “Here in Spain many murders are committed on account of jealousy or revenge. No doubt the motive was either one or the other.”

“Terrible!” exclaimed Sylvia, shuddering at the thought of being flung over upon the crags below.

“Yes. In Spain they regard death at the Crow’s Cliff as the most ignominious end any person can suffer,” remarked her hostess. “I’ve heard all sorts of weird stories about the place, which was a place of execution long before the days of the Inquisition. The peasantry believe that on certain nights the ghosts of black-robed and masked executioners haunt this road.”

The girl laughed.

“Of course the ignorant country folk would naturally invent all sorts of horrible stories.”

“Well, it’s a horrible spot altogether,” declared Falconer. And the party walked back to El Pardo together, where they dined late, and it was past midnight before Geoffrey arrived back at Aranjuez.

While during the next few days he continued his work at the great wireless station there—the station known to all wireless men as “E.A.A.,” and which works so regularly with Poldhu—Sylvia and her mother were taken about the country by their hostess to see old-world Toledo, Villarrubia, Talavera, and the Tetas de Viana.

A bald-headed Spanish doctor named Garcia, with his wife, a very handsome woman, had arrived from Burgos, and were also guests of the Mapletons. The Garcias had lived in Madrid for several years, and were great friends of the Mapletons.

Indeed the truth was that when Dr. Garcia had found himself in serious financial difficulties three years before, the banker had secretly assisted him. Hence the doctor was considerably in his debt.

One evening, a fortnight later, the party had been out to dinner at a neighbouring house, and on their return Mrs. Mapleton was suddenly taken very unwell. Her husband and the others became greatly alarmed, and the faithful Martin, who, in turn, became full of apprehension, called Dr. Garcia, who had already retired to bed.

The doctor, when he examined the lady and noted the symptoms, came to the conclusion that she was suffering from acute indigestion, to which, apparently, she was subject. Something she had eaten at dinner had no doubt affected her, for by three o’clock in the morning she was much easier, and by next day the attack had passed.

Indeed they motored into Madrid in the afternoon, where they visited the wonderful private collection of pictures belonging to the Duke of Alba, and the Prado Museum, afterwards enjoying that wonderful view from the Campillo de las Vistillas. Yet on the same evening Mrs. Mapleton was again taken unwell, and the same remedy which Dr. Garcia had prescribed was resorted to, with the result that two hours later she was quite herself again.

Next day when at breakfast, Mrs. Mapleton said to Madame Garcia:

“These attacks of indigestion are most annoying. Time after time I get them badly—and then I recover just as suddenly as I am attacked. The first time I had one was a year ago—and I was terribly ill for three days.”

“But the doctor has put you upon special diet,” was madame’s reply. “If you keep to that you will certainly be all right.”

Martin, who chanced to enter the room at the moment, eagerly asked after his mistress’s health.

That same afternoon Sylvia had an appointment with Geoffrey in Madrid. Her lover had been out at Aranjuez, busily engaged all day trying to improve the continuous-wave panel, and was in ignorance of Mrs. Mapleton’s indisposition. They, however, met as she had arranged, in the palm-court of the great Ritz Hotel in the Plaza de CÀnovas, and sat down to a pleasant tea.

While chatting together the girl suddenly became very serious, saying:

“There’s something on my mind, Geoffrey—and—well, I hardly know what to say to you.”

“On your mind!” he echoed. “Why, what about?”

“Well, about Mrs. Mapleton. She’s had two sudden and serious attacks on successive nights. Dr. Garcia, whom you met at El Pardo, put it down to indigestion, but—well, I don’t think it is,” said the girl.

“You seem worried about your hostess,” he remarked.

“Yes. The fact is I’m suspicious of that woman, Madame Garcia.”

“Oh! Why?”

“Well, strictly between ourselves, Geoffrey, very late the other night when every one was asleep I heard Mr. Mapleton quarrelling with his wife, and the doctor’s wife was mentioned by our hostess, who is, no doubt, jealous of her, though she will not show it in public.”

“Oh! Then Mrs. Mapleton is jealous of madame—eh?”

“Yes. And this knowledge has aroused my suspicion. If Mr. Mapleton admires madame, there may be some subtle plot to get Mrs. Mapleton out of the way!” she said.

Geoffrey looked at her open-mouthed.“Do you really believe that?” he asked quickly.

“I most certainly do. I haven’t mentioned anything to mother,” said the girl. “But I shall be very glad to get away from the place. I’m going to urge mother to make an excuse and cut short our visit.”

“No. Don’t do that,” he answered quickly. “If evil is intended, as you surmise, then your place is there to watch carefully and report to me. Our duty is to save the lady and expose the plot.”

“Spaniards are experts with poisons,” Sylvia remarked.

“I know. Therefore we should both act warily, and await the next development. In the meantime I will make some inquiries regarding the Garcias, who are so well-known here in Madrid.”

What Sylvia had suggested at once aroused Geoffrey’s curiosity, and that evening he took his idol back to the Mapletons at El Pardo, where he was invited to remain to dinner.

He watched Mr. Mapleton and the doctor’s wife very carefully, but he could not detect any sign of undue admiration. Indeed the banker scarcely took any notice of her, being much more attentive to Mrs. Beverley, his guest, while the bald-headed Dr. Garcia was most affable to Geoffrey himself.

The dinner was a merry meal, and every one was chatting about the lovely motor-run they had made during the warm afternoon out to Sonseca, in the Mountains of Toledo, while Martin, grave-faced and urbane, served his master’s guests in eloquent silence.

Falconer, sorely puzzled, left early to get back to Aranjuez. He could now fully understand the suspicions of Sylvia, yet he felt inclined to dismiss them, for he could discover nothing unusual in the Mapleton mÉnage.

Next evening, however, after his work was over, he went into Madrid in order to institute the inquiries he had promised Sylvia to make.

Of several persons whom he had met since his arrival from England he made inquiry regarding Dr. Garcia. From an old Spaniard, who was manager of an antique shop in the Calle de Don Pedro, and whom he had met out at Aranjuez with one of the wireless operators, he learned a few interesting facts concerning the bald-headed doctor.

“Oh, yes,” replied the old fellow in broken English, “Dr. Garcia is very well known in Madrid. He married a woman from Burgos, Carolina Almagro, about five years ago. She was previously engaged to marry the English banker, SeÑor Mapleton.”

“What?” gasped Geoffrey. “Was Madame Garcia once engaged to marry Mr. Mapleton?”

“Oh, yes, seÑor. Every one in Madrid knows that.”

Geoffrey Falconer held his breath, and remained silent for a few moments.

“But how long has Mr. Mapleton been married?”

“Oh, about four years—not more. He married an English lady—and a very nice lady she is. Once or twice she has bought old furniture here.”

“But Dr. Garcia and his wife have left Madrid,” Geoffrey remarked as they sat together in the dark little shop, surrounded by all sorts of curios.

“Yes. He sold the practice to Dr. Salcedo soon after his marriage, and went away. I don’t know where he is now.”

“But tell me,” urged Geoffrey. “How is it that the lady, being engaged to the banker, married the doctor?”

The old man grinned, while his black eyes twinkled.

“There was a whisper of some scandal. They say that is the reason why the doctor and his wife left Madrid.”

All that was being told to Falconer went to establish the motive why a secret attempt should be made upon Mrs. Mapleton’s life. It was all news to Geoffrey. He had believed that Mapleton had been married fully ten years.

In other quarters he prosecuted inquiries, but the result was always the same—the story of the sudden marriage of the English banker’s Spanish fiancÉe, and the gossip which ensued.Several further days passed, and then one evening Geoffrey, having been to the Eslava Theatre, was leaving in order to return to Aranjuez, when, to his surprise, he saw walking along the dark street in front of him the familiar figure of Mr. Mapleton, and at his side was Madame Garcia!

They had evidently been to the theatre together. He followed them unseen, and saw them enter the car, and drive back to El Pardo together.

This, indeed, further aroused his suspicions concerning Mrs. Mapleton’s repeated seizures.

Next afternoon he went to El Pardo again with the express purpose of keeping his eyes open, and also of telling Sylvia in confidence what he had learnt.

The pair while walking in the garden agreed that there was distinct suspicion that either Mr. Mapleton might be plotting to get rid of his wife, or that the handsome Spanish woman might be endeavouring to poison her rival through motives of jealousy. As Sylvia pointed out, Mapleton was very rich, while Madame Garcia was the wife of a poor professional man in financial difficulties. The woman could not obtain the luxuries, smart dresses, and sojourns at Aix, Dinant, or San Sebastian, for which she longed.

“She is always deploring the fact that she leads such a humdrum life,” the girl went on. “Only yesterday she told me that she envied us, travelling about as we do.”

“Well, personally, I don’t like madame,” her lover said. “Her eyes are cruel and vindictive, and she seems to bear an entirely false affection for her hostess.”

“Mrs. Mapleton is charming,” declared Sylvia as they halted on the terrace, from which a beautiful view of Madrid could be seen across the plain. “I wonder if her husband has any suspicion? Surely Dr. Garcia could discover whether those mysterious attacks are due to indigestion—or to foul play?”

“The doctor’s wife would never let her husband into her guilty secret,” Geoffrey said. Then after a pause, he added: “Of course if the banker himself had experienced similar seizures one could discern in them a motive—namely, that the doctor being deeply in his debt wanted to get rid of him, for by his death he would get out of his heavy liabilities. But the affair concerns only the banker’s wife.”

“It’s a complete mystery, Geoff,” declared the girl. “I watch them all closely day after day, but I become more and more mystified. I long to tell mother, but I have acted upon your advice, and kept my own counsel. Only to-day at breakfast Mrs. Mapleton, who, of course, is all unsuspecting, invited the Garcias to remain for another fortnight. After that they are going to Granada. And a week later the Mapletons go to Barcelona, where he has a branch of his bank, while we go back to London.”

“Then during the next fortnight we must be very watchful,” Falconer said, and as at that moment Mrs. Mapleton, walking with the handsome Madame Garcia, came along the terrace, they dropped the subject, and Falconer became most enthusiastic regarding the glorious view.

Next morning at about ten o’clock Geoffrey Falconer was busy re-wiring part of the powerful transmitting apparatus at the wireless station at Aranjuez, when one of the operators handed him a telegram which had just been received over the land line from Madrid.

It was open, upon a form, just as it had been received. The words he read were:

“Another seizure. Unconscious for three hours. Just recovered. Meet me at the Ritz in Madrid at four this afternoon.—Sylvia.”

Geoffrey realised the extreme gravity of the situation. He had been making many secret inquiries. The mystery of it all had not only fascinated him, but it had placed him upon his mettle. Sylvia, the girl whom he loved so passionately, had, by her woman’s shrewd keenness, first aroused the suspicion which had daily grown stronger until the grave peril of the banker’s charming wife obsessed him.

On five different occasions, from that complicated-looking apparatus of the high-power wireless station, with which at the moment he was surrounded, he had sent out with great difficulty and very weakly in the Marconi International Code, long messages to M.P.D.—or Poldhu in Cornwall—inquiries concerning Mapleton and others—which next day had been answered in the same code.

These answers, unknown to Sylvia, had opened up an entirely new channel of inquiry. That telegram from El Pardo confirmed certain suspicions which had come to him during the past two days.

That there was a deliberate and desperate attempt to get rid of Mrs. Mapleton had become an established fact. It only lay with Sylvia and her lover to save the unfortunate victim, to lay bare the plot, and to bring the guilty person or persons to their just punishment.

When at four o’clock Sylvia met Geoffrey in the Ritz, her first words were:

“Poor Mrs. Mapleton had a terribly narrow escape last night! Dr. Garcia grew very alarmed, and at two o’clock this morning telephoned to Madrid to Dr. Figueroa, who, I believe, is one of the most distinguished pathologists in Spain. He arrived at about half-past four, and in consultation agreed with Garcia that it was acute indigestion. Fortunately, an hour afterwards Mrs. Mapleton was quite well again.”

“And what was the attitude of Madame Garcia?” asked Geoffrey eagerly.

“Oh, very agitated and fussy, of course, all of it well assumed. She’s a most wonderful actress. All the women of the South are the same.”

“But does Garcia know?”

“I feel sure he is in complete ignorance. I watch them all every hour—every minute—but I can find no tangible evidence against anyone. The only motive that there can be is Madame Garcia’s jealousy.”“Then she must be the culprit,” Falconer said. “It is evident that she must somehow doctor her hostess’s food—eh? But surely that must be difficult.”

“No doubt, but it is being accomplished somehow, for how is it that none of us suffer from any ill-effects?” said the girl.

“Because you are not subject to ‘acute indigestion’ as Mrs. Mapleton is,” was his reply as he smiled meaningly. “The attacks are certainly curious. They seem to occur after eating, just as indigestion would occur,” Falconer went on. “But how is it possible that this Spanish woman can tamper with her hostess’s food alone, unless she is in league with the cook, and that is quite inconceivable. The whole history of both Garcia, and his wife, and Mapleton and Mrs. Mapleton certainly points to but one motive—Madame Garcia’s jealousy!”

“But do you think that Mr. Mapleton can have no knowledge of what is in progress?” asked the girl to whom the young wireless engineer was so devoted.

“No; I’m convinced that he has not. His friend the doctor has diagnosed the complaint as indigestion, hence he has no suspicions, and does not seek a further medical opinion.”

“That is so. Mother only yesterday suggested to him in private that he should ask for another doctor to see his wife, but he declared that he had the greatest confidence in Dr. Garcia’s judgment.” Then she added: “It was Dr. Garcia himself who sent into Madrid for another doctor this morning.”

“Then we can do no more, save to still prosecute inquiries, and watch the progress of events.”

During the next two days young Falconer was very busy making some tests with Poldhu. From the “Devil’s Oven,” far away on the rocky Cornish coast, they at first sent him replies on “spark” in response, but after twenty hours of hard work, during which they constantly disturbed the ether by sending long and numerous series of “V’s”—namely, three dots and a dash—the letter of the alphabet used in wireless for testing purposes, his transmission was at last declared by Poldhu to be “good,” but not anything really great—in fact “R.7.,” as Poldhu put it.

There was still a fault somewhere, and amid that tangle of wires, the mass of up-to-date apparatus, and the great vacuum glass globes—huge balls of light when transmission was in progress—he stood dismayed and puzzled. A fault in wireless transmission is often most difficult to trace, and it was so in this case. The two engineers at Aranjuez had failed to discover it, and for that reason young Falconer had been sent over as an expert to find and remedy it. It was the more baffling because after re-wiring it the first time, he was able to communicate with Poldhu about Dr. Garcia and Mapleton. Then a slight fault had necessitated an alteration, and now it was again wrong.

As he stood there that morning gazing into the big valve-panel, undecided as to what test next to apply, one of the operators, a young Spaniard, handed him a message form, saying that it had just come in from Poldhu. It was in the International Code; therefore Falconer went to the adjoining room, and taking down the big book which gives a “figure” and “letter” code in all the principal commercial languages, including Japanese, he soon succeeded in de-coding the message.

When he did so he sat back aghast. The truth was now apparent.

His inquiries in London regarding the Mapletons were slowly throwing a light upon a most dramatic situation.

That day he felt justified in leaving his work early, and in the evening he travelled to the far north of Spain to San Sebastian, that gay seaside resort which is the favourite summer resort of the MadrileÑos. He arrived there in the early morning, having spent the night in the so-called “express.” He took his coffee at the old-fashioned HÔtel Ezcurra, in the Paseo de la Zurriola, and then he went round to the Prefecture of Police.To the rather lazy underling whom he found there he made an explanation, and at ten o’clock he was shown into the bureau of the chief of police himself, an elderly, alert little man, who listened to the young Englishman very attentively. As he proceeded with his story, and as he related what had been sent by wireless from England, the official’s interest grew.

For two hours Geoffrey Falconer remained there, examining documents, and questioning four Spanish detectives by the aid of the official interpreter.

“And now, SeÑor Falconer,” said the chief of police at last, “the best line of action for you is to return and keep a secret and strict watch. You know all I have told you, and what are my suspicions. It is fortunate, very fortunate, that your young lady friend has detected what is in progress. On my part I will send by to-night’s mail a report to the police of Madrid, who will be on the alert for any developments. They will place our great pathologist, Professor Barrera, at your disposal, should any analysis be required. We are at the moment quite powerless to act, but we look to you for such information as shall save the lady’s life.”

About noon on the following day Falconer called at the Mapleton’s house in El Pardo as though upon a casual visit. As soon as he met Sylvia, the girl called him aside, and whispered:

“I’m so glad you are here, Geoffrey. Mrs. Mapleton had another attack last night, but is better now. She is in the habit of eating but very little dinner, and taking some patent invalid food just before going to bed. I managed to save a little of it before Martin cleared it away. I’ve got it in a bottle upstairs.”

“Excellent. I will take it at once to Professor Barrera,” replied Falconer. “He will analyse it, and see whether it has been doctored.”

The young Englishman remained to luncheon, and then, without telling anyone of his journey to San Sebastian, he went back to Madrid, and there saw the Professor, who had already been warned by the police.Next day, when Falconer called upon Professor Barrera, he was told that into the invalid food had been introduced the juice of a certain poisonous mushroom which produced the exact symptoms of acute indigestion, and which, when absorbed by the human body, was almost impossible to detect. It was one of the most subtle and dangerous poisons known to modern toxicologists.

“The mushroom is a large dark-grey fungus with scarlet spots and grows on the mountains. It is found often in the Guadarrama,” he said. “Whoever is using it must be an expert poisoner.”

With that knowledge, and the other knowledge he now possessed, Falconer waited until evening, and then returned to El Pardo, where he was asked to remain to dinner, and to sleep, as a motor excursion had been arranged for the following day.

He dined, but though he went to his room, he could not sleep. The night was moonlit, and from his window he had a good view of the white road outside. Instead of undressing, he watched that road through the night hours until the first streak of dawn. It slowly became light at about four o’clock, when suddenly he saw the figure of a man going out upon a brisk walk.

Without a second’s hesitation he took his hat, and creeping silently down the stairs, let himself out.

By that time the man, whose figure he had recognised as Martin’s, was far ahead. The morning mist was thick as, leaving the highway, he ascended the steep hill-path, Geoffrey, whose rubber-soled boots made but little noise, following swiftly.

The rough winding way led to the summit of the Crow’s Cliff, until Martin at last reached the top.

Then Geoffrey saw the butler bending down, eagerly, examining a patch of grass near the edge of the Cliff He was searching for that deadly grey fungus with the scarlet spots, which, when gathered at dawn, was most dangerous to human life!

Falconer, modest in his scientific achievements, but bold when faced with an alternative, saw the man in the act of picking one of the mushrooms, and suddenly sprang upon him.

“At last, Martin!” he cried. “So it is you who are trying to poison your mistress! Now I know the truth!”

The fellow, his face blanched, flung himself free.

“What do you mean?” shouted the exemplary butler in wild defiance.

“I mean that you are not Mrs. Mapleton’s servant at all! You are her rightful husband, and moreover you were a partner with her in certain shady transactions. You and she ran a private gaming-house in Bayswater, and afterwards at San Sebastian. From the profits of the place Mrs. Mapleton derived her private income, unknown to Mapleton, who believes it is from Consols. Four years ago one Paul Berton, a rich French landowner, was robbed and died mysteriously in that house in San Sebastian—killed in circumstances which left no doubt in your wife’s mind that you were the assassin.”

“It’s quite untrue!” protested Martin.

“Let me go on,” said Falconer. “Your wife hated you, because you were a murderer. She fell in love with Mapleton, and under threats of disclosing your crime to the police, she compelled you to remain aside, and she married the man she loved. Then you persecuted the unfortunate woman, who believed that she was safely out of your clutches. You compelled her to engage you as her butler. Why? Your first idea was to poison Mapleton, so that you should get his money through his wife. But when she saw through your plot and threatened to expose you, you sought to secretly poison her, and thus close her lips—at the same time throwing suspicion upon the jealous woman, Madame Garcia!”

“A lie—an absolute lie!”

“No, it is the truth, Mr. Sharman—alias Barnes—alias half a dozen other names. Your record is at Scotland Yard, together with your finger prints. I have them in my pocket. Truly, yours is a dastardly and ingenious game. You poisoned poor Berton with the same decoction of mushroom-juice that you are now using on your wife!”

Without a second’s delay the man Martin sprang at Geoffrey, who was close to the edge of the Crow’s Cliff—the execution place of the Middle Ages. Next moment the young radio-engineer, feeling himself gripped suddenly and rushed to the edge of the precipice, executed, to save his life, a very clever manoeuvre, and by dint of some swift athletic turns he succeeded in swinging round his adversary until the latter had his back to the precipice.

The two men fought for life, there upon the very brink of the grave! Martin was determined to silence his accuser.

But Geoffrey, who at Oxford had learnt the Japanese system of self-defence, suddenly gripped the assassin by the waist, and rushing him backwards to the cliff, flung him from him with force, crying:

“That is your fate—the same that every secret poisoner deserves!”

There was a scream, and next instant the scoundrel struck a pointed rock just below. Then he fell heavily from crag to crag until, a few seconds later, he lay deep down in the undergrowth at the cliff foot, mangled and dead—his fate being indeed a just one.

Next day the ImparÇial, in Madrid, printed a long account of the tragic discovery, with a photograph of the dead English servant. The paper called it “The Mystery of the Crow’s Cliff.” But even to-day Mr. Mapleton with the doctor and Mrs. Garcia naturally regard the whole affair as a tragic mystery, for they still aver that the butler Martin was one of the most trustworthy of servants, and believe that he must have met with foul play at the hands of some low-born enemy. Mrs. Mapleton alone suspects the truth!

Three months after the affair Geoffrey Falconer, who had been paid a very considerable sum for the rights of his improved microphone amplifier and for several improvements in wireless calling devices, asked Mrs. Beverley for her daughter’s hand.

The “Wild Widow” admired him, and after a long discussion, gave her consent. So six months ago they were married at St. Martin’s-in-the-Fields, and at the wedding nearly half the engineering staff from the Marconi Works at Chelmsford attended.

Truly the guilty secrets of many men and women have been detected by means of wireless, that science which daily reveals its further wonders to those persevering experimenters who seek so patiently to penetrate its mysteries.

THE END

Cahill & Co., Ltd., London, Dublin, and Drogheda.