On reaching the house, Boyd, an expert officer who had spent years in the investigation of crime, ascended with his subordinate to the drawing-room, while we remained on the ground floor to complete our search, the sergeant being stationed inside the hall.

Our further investigations were not very fruitful. The fact that dinner was laid for three indicated that a third person had been present, or was expected. The room did not differ from any other, except that it was perhaps better furnished than one would have expected in such a house, for although in a first-class and rather expensive neighbourhood the row of houses had declined in popularity of late years, and was now inhabited mostly by the lodging-house fraternity.

In moving about the room, however, my coat caught the plate laid for the person who was to occupy the head of the table, and it was nearly swept off. I saved it, however, but beneath was revealed a plain white card which, until that moment, had been concealed. Patterson caught sight of it at the same moment, and taking it in my hand I examined it, finding that it was a plain visiting card of lady’s size, one side being blank, and other bearing a roughly-drawn circle in ink.

There was nothing else.

“That’s certainly curious,” my companion remarked, looking over my shoulder.

“Yes,” I said, lifting a second plate to see what was there concealed, and finding another card, in all appearances similar, plain, but bearing across its reverse a single straight line drawn with a pen.

“By Jove!” observed Patterson, lifting the other plate, and finding a third card, “this is certainly very strange.”

He turned the card over, but it was blank on both sides.

“I wonder what game is this, or whether these have any connexion with the crime?” I exclaimed, holding all three of the cards in my hand, turning them over and examining them carefully beneath the light. “By the ink they have the appearance of having been prepared long ago. See!” I added, holding one of them towards him, “the corners of this one are slightly turned up and soiled. It has been carried in some one’s pocket, and is not a fresh card.”

Again Patterson took it and examined it. It was the one with the line drawn across it. The others were quite clean, as if just taken fresh from a packet.

“There’s some mystery about these,” he said reflectively, as though speaking to himself. “If we could but solve it we should likewise solve the problem of the crime, depend upon it.”

“No doubt,” I assented. “Each of them have some meaning, occult but extraordinary. They were turned face downwards so that the accidental removal of the plate would not reveal the device upon them.”

“The devices are simple enough, but undoubtedly they have some hidden meaning,” my friend said.

“They were evidently concealed there, and the three persons, unsuspecting, were to discover them when the first plates were removed,” I suggested.

He placed them together on the table, saying —

“Better let Boyd see them when he comes down. The affair grows more queer and complicated as we proceed.”

“Don’t you recollect,” I said suddenly, “in the dead man’s pocket was a card exactly similar, but quite blank. You threw it into the fireplace.”

“Ah! of course,” he answered quickly. “That fact shows that he had something to do with these mysterious symbols. I wonder what is their real meaning.”

“I wonder,” I said. “As you say, the mystery grows each moment more and more inexplicable. Curious, too, that the snake in the garden path should have directed your attention to it.”

“No,” he said quickly, his face in an instant pale and serious, “don’t mention that, there’s a good fellow. I’m trying not to think of it; for when I recollect all that it means to me I’m unnerved.”

“Bah!” I laughed. “Surely there’s nothing to fear. It only shows that however careful the assassin is to cover his crime it must be unearthed sooner or later. The finger of Fate always points to the crime of murder, however well it may be concealed.”

“True,” he sighed, his brows knit in serious thought. “But the finger of Fate has in this case shown me an omen of evil.”

“You’re a fool, Patterson,” I said bluntly. “You have here every chance to distinguish yourself as a shrewd officer, yet you calmly stand by talking of omens and all that rot.”

“Yes,” he answered. “I know I’m an idiot, Mr Urwin, but I can’t help it. That’s the worst of it.”

“Well,” I suggested, “while Boyd is upstairs, why not make inquiries of the next-door neighbours regarding those who occupied this place?”

He at once acted on my suggestion, and together we went out and rang the bell of the house adjoining on the right. My friend’s curious apathy in this matter surprised me, for usually he was a quick, active fellow, who prosecuted his inquiries methodically, and worked up evidence in a manner that had more than once called forth the commendation of the judge at the Old Bailey. That night, however, he was plainly upset – nervous, trembling and agitated, in a manner quite unusual to him.

Boyd, the keen-eyed, quick-witted detective inspector, had noticed this when at the police-station, but Patterson had only replied —

“I’m a bit unwell, that’s all.”

Our summons at the house next door was answered by the occupier’s wife, a rather stout, white-haired, gaily-capped old lady named Luff.

The appearance of Patterson in uniform surprised her, but when she had asked us in, and we were seated, he said —

“There is no occasion to be alarmed, madam. I have merely called to make an inquiry of you. It is in your power to render us assistance in a rather confidential matter regarding the occupiers of the house next door – your neighbours on the left. What do you know of them?”

“Nothing,” she answered. “They came about six months ago, a young lady and a very old gentleman, with a single maid-servant. They speak to no one, and, as far as I have observed, have very few friends. I have often remarked to my son, who is a civil engineer, and now away making the railway in China, that they are a mysterious couple. What is wrong with them?”

“Oh, it’s simply a private matter,” my companion answered carelessly, not wishing to alarm the neighbourhood by news of our discovery.

“What is the old gentleman like? Can you describe him?” I inquired. No doubt she took me for a detective, but at that moment this thought did not occur to me.

“He is sixty, I should think, old and decrepit, with white hair, and always walks with a stick.”

“And the lady was his daughter?” suggested the inspector.

“I suppose her to be his daughter,” she answered. “The old man’s name is Dawson, I believe – at least one day a messenger-boy brought a note here by mistake, addressed to Professor Dawson. The daughter is a very good pianist, and plays every morning regularly.”

“They are well off, as far as you can judge?” Patterson inquired with his assumed careless air.

“No, I don’t think they are, because my maid heard at Boucher’s – the grocer’s across the way – that they owed a large bill which they couldn’t settle. Again, people who have a house of that sort do not have coal by the hundredweight taken down into the kitchen as they do.”

Patterson nodded. No more sure sign of a light purse is there than the purchase of coal by the half-sack. Yet the interior of that house, with its well-laid dinner-table, certainly did not betray any sign of poverty. Indeed, I had noticed in the cellar a dusty stock of choice wines, hocks, ports, and champagnes of expensive brands.

“You don’t know the young lady’s name, then?” asked my friend, after a slight pause.

“If she’s really his daughter it would, I suppose, be Dawson,” she replied with a smile. “But I’m not certain, remember, as to either of their names.”

“Perhaps your servants may know something about them. Servants generally gossip and pick up information about one’s neighbours, you know.”

“You are right,” answered the affable old lady, “they gossip far too much. Unfortunately, however, both my servants are out at this moment.”

We chatted on, but it was evident from her conversation that her servants knew little beyond what she did. One statement she made was somewhat curious. She alleged that a few nights before she was awakened about two o’clock in the morning by hearing the loud shrill screams of a woman who seemed to be in the room next hers in the adjoining house. She could hear a man’s voice talking low and gruffly, and three or four times were the screams repeated, as if the woman were in excruciating pain.

“What visitors came to the house?” Patterson asked at length.

“Very few. A youngish gentleman came sometimes. He called the other morning just as I was going out.”

“Who admitted him?”

“The young lady herself.”

Many more questions Patterson put to the old lady, but elicited no noteworthy fact, except that two large, heavy trunks had been sent away by Parcels Delivery a couple of days before. Therefore, thanking Mrs Luff, who, of course, was extremely curious to know why the police were taking such an active interest in her neighbour, we left and made inquiries of the people in the adjoining house on the opposite hand.

It was a lodging-house and the owner, a rather surly old widow, was not at all communicative. What she told us amounted practically to what we had already learnt. She, too, had long ago set the old man and his daughter down as mysterious persons, and her two servants had never been able to find out anything regarding them.

So after nearly half an hour’s absence we returned to the house of mystery, watched, of course, by the persons in the houses on either side. None suspected a tragedy, but all remained at their windows expecting to see somebody arrested.

In the dining-room we found Doctor Knowles, the police divisional surgeon, who had been sent for by the police. He had already examined the bodies and was on the point of returning home.

“Well, doctor, what’s your opinion?” asked Patterson.

“I can form none until after the post-mortem,” answered the prim, youngish, dark-moustached man in silk hat and frock coat, a typical Kensington practitioner, who was known to be a great favourite with his lady patients.

“Are there no marks of violence?”

“None,” he responded. “Although there seems no doubt that there has been foul play, yet the means used to encompass their death remains an entire mystery. That laboratory, too, is a very remarkable feature.”

“Why?” I asked.

“Because the occupant of that place has made a discovery for which scientists have for years striven in vain,” the doctor replied.

“What is it?”

“You noticed those strange globes with the coil of tubing,” he said. “Well, from what I’ve found, it seems that the experimenter has invented a means for the liquefaction of hydrogen in large quantities.”

“Is that anything very remarkable?” I asked, in my ignorance of recent science.

“Remarkable!” he echoed. “I should rather say it was. The discovery will create the greatest interest in the scientific world. Other gases have all been handled as true liquids in measurable quantities, while until now hydrogen has only been seen in clouds or droplets, and never collected into a liquid mass. Upstairs, however, there is actually a glass bowl of liquid hydrogen. The experimenter, whoever he is, has determined at last the exact temperature at which it will liquefy, and thus a field for quite new researches, as also for new generalisations, has been thrown wide open.”

“But why is the discovery so very important?” I asked, still puzzled at the doctor’s unusual enthusiasm.

“Briefly, because by it physicists and chemists can henceforward obtain temperatures lying within thirty-five degrees from the so-called absolute zero of temperature – minus 459 degrees Fahrenheit. A possibility is thus given to study physical bodies in the vicinity of that point, which represents, so to say, the death of matter – that is, absence of the molecular vibrations which we describe as heat.”

This explanation, technical though it was, interested me. I knew Doctor Lees Knowles to be a rising man, and when reporting lectures at the Royal Institution had often noticed him among the audiences. There was no doubt that he was highly excited over the discovery, for, like myself, he had seen the liquid hydrogen boiling without any visible heat. In the papers there had been lots about Professor Dewar’s experiments in the liquefaction of oxygen, fluorine and the newly-discovered helium, and I remembered how all his efforts to bring hydrogen to a liquid state had failed. Now, however, the mysterious occupier of that house had succeeded, and every known gas could now be liquefied.

“But the murder,” observed Patterson, his thoughts reverting to the crime, for to him the most wonderful scientific discovery was as naught. “Can you form absolutely no opinion as to how it was accomplished?”

The doctor shook his head.

“There is nothing whatever to account for their sudden death, as far as I can observe,” he answered. “To the woman, however, death must have come instantly, while the man must have fallen and expired a few seconds later. There seem many mysterious features in the affair.”

“The discoverer of this latest scientific fact is undoubtedly the old man who is absent, the father of the dead girl. From him we may learn something to lead us to form conclusions,” I suggested.

“An old man!” echoed Dr Knowles. “Tell me about him.”

Briefly Patterson related all that had been told us by the neighbours, and when he had finished the doctor exclaimed —

“Then I can tell you one thing which is proved undoubtedly. The old man seen to go in and out was in reality a young one, for while looking over the laboratory I came across a white wig and a make-up box, such as is used by actors. Go upstairs and you’ll find a complete disguise there – broadcloth coat, pepper-and-salt trousers baggy at the knees, old-fashioned white vest, and collars of antique pattern.”

“Surely that can’t be true!” Patterson exclaimed in amazement.

“It certainly is,” the doctor asserted. “Depend upon it that the man lying upstairs dead was the man who has been making these successful experiments, and who for some unknown reason desired to conceal his identity. Recollect that they had few friends, if any, and that their man-servant was a most discreet foreigner, who never gossiped.”

“Then you think that to the world they assumed the position of father and daughter, while in reality they were husband and wife?” I said.

“Most likely,” responded the doctor. “A man to make experiments on an elaborate scale as he has must necessarily have been absorbed in them. Indeed, that apparatus must have taken a year to prepare, and no doubt he has been making constant trials for months. He probably intended to give forth his discovery to the world as a great surprise, but has been prevented from doing so by some extraordinary combination of circumstances which has resulted in his death.”

At that instant we heard a voice in the hall – a quick, sharp voice extremely familiar to me, but nevertheless it caused me to start. Next instant, however, there entered the room the well-known figure of Dick Cleugh.

“Hulloa, old fellow!” he exclaimed, greeting me and taking me aside. “I thought I’d run down and see what’s in this. Funny affair it seems, doesn’t it?”

“Yes,” I answered. “A most remarkable mystery. But why have you come out here?”

“Soon after you left I went to find Lily, but she’s gone into the country. So having nothing else to do I came down to see what had occurred. I knew, of course, from Patterson’s telegram, that it was something unusual.”

“Have you been upstairs?”

“Yes, I’ve been worrying around this last half-hour, while you and Patterson have been making inquiries next door. I’ve been having a look about with the Doctor. It seems that there’s some wonderful apparatus in the laboratory – a discovery for liquefying hydrogen. Has he told you about it?”

“Yes,” I responded. “What’s your theory?”

“By Jove! old fellow,” he said smiling, “the whole affair is so devilish uncanny, with those snakes upstairs, water boiling without any heat beneath it, and one thing and another, that I’m utterly at a loss how to account for it all.”

“You think they’ve been murdered?”

“Of course,” answered the astute Cleugh. “But the doctor can’t discover how. There is not a scratch upon them. The discovery of those flash notes on the man looks as though he were a bit of a swell swindler, doesn’t it?”

“Yes,” I said. Then taking him across to the dining-table I explained how we had discovered the three cards concealed beneath the plates.

He took the cards in his hand, turning them over, and examining them carefully.

“Strange,” he ejaculated. “This adds still another phase to the affair. It is really a most sensational discovery, and will work up well for to-morrow.”

“No, Mr Cleugh,” put in Patterson quickly, overhearing his remark, “I beg of you to publish nothing whatever about it until I give you permission. In this we are bound to preserve secrecy for the present in order that our inquiries may not be thwarted. Even the neighbours will remain in ignorance of the real nature of things, so carefully do I intend to guard against any public sensation. Whatever information I can give you I will do so willingly, in order that you can prepare your account of it, but remember that not a word must be published until I give you permission.”

“Quite right,” observed the doctor. “In such a matter as this any sensation in the Press might frustrate all your efforts to arrive at the truth.”

“Very well,” answered Dick, a trifle disappointedly. “Of course you’ll give nothing to anybody else. I want to be first in the field with it.”

“Of that I give you my word. Not a soul will know of this discovery outside the persons in this house at the present moment. Come, let’s go upstairs and speak to Boyd,” and while the doctor wished us good evening and left, my two friends accompanied me upstairs, where in the drawing-room the detectives were continuing their searching investigation.

“The woman is decidedly good-looking, isn’t she?” observed Cleugh as we entered.

Instinctively I turned towards the chair in which the body was still reclining, but next instant, with a loud cry of dismay, which at the same moment was echoed by Patterson, I stood aghast, rigid, immovable.

The sight which met our eyes was utterly bewildering.

The woman we had discovered there, so lovely in form and feature, had a wealth of auburn hair, and eyes of a deep intense blue, while, amazing though it was, this woman before us was quite ten years older, dark-complexioned, with hair which in that light seemed blue-black, and half-closed eyes as dark as jet.

“Good Heavens!” I gasped. “Look! Why, that is not the woman we found when we first entered this place – but another. Where is the fair girl?”

“There’s no fair girl,” answered the detective Boyd, as all started back in surprise at my astounding assertion. “This is the woman we found, you must be mistaken.”

“No,” Patterson declared in the low, hoarse voice of one filled with fear. “There is no mistake. When we first entered there was another woman here, younger, prettier, with light hair and blue eyes. This is the most unaccountable, most amazing and most inexplicable of all our discoveries.”

Chapter Five
The Second Woman

The statement that the woman found by Patterson on his first entry there, and seen by me afterwards, had disappeared, was at first discredited by our companions. It seemed too astounding to be the truth, nevertheless there was now reclining in the same armchair a woman who certainly bore no resemblance whatever to the beautiful, fair-haired girl with eyes of such deep, pure blue – those eyes that had stared at me so horribly in the ghastly rigidity of death. I recollected that smile upon her lips, half of sarcasm, half of pleasure; that strange expression which had held me entranced yet horrified.

She had disappeared, and here in her place was a dark-complexioned woman, older, nevertheless handsome – a woman in whose refined face was an air of romance and tragedy, and upon whose hand was the marriage bond. She, too, was dead. The doctor had examined her and pronounced life extinct.

“How could this have occurred?” I exclaimed, turning to Patterson as soon as I had recovered from the shock of the astounding discovery.

“It’s simply amazing!” he declared. “I’m utterly at a loss to account for it. The woman we found here was most distinctly another person.”

“Then there has been a triple tragedy,” observed Boyd. “The body of the first woman must have been conveyed away during the time you were absent at the police-station.”

“But why?” I asked. “What on earth could be the motive?”

“Impossible to tell,” Patterson answered. “Perhaps the body is hidden somewhere in the house.”

“No,” Boyd replied. “We’ve made a complete search everywhere. It has undoubtedly been taken away. This fact, in itself, shows first, that there is more than one person implicated in the crime, and secondly, that they were absolutely fearless; while further, the incident of the telephone is in itself sufficient proof that they had taken the utmost precautions against detection.”

“Are you quite certain that every cupboard and wardrobe has been looked into?” I asked doubtfully.

“Quite. From garret to cellar we’ve thoroughly overhauled the place. There are a couple of large trunks in one of the bedrooms, but we examined the contents of both. They contain books.”

“But loose boards, or places of that sort?” I suggested.

“When we search a place,” responded the Scotland Yard inspector with a smile, “we’re always on the look-out for places of concealment. I’ve superintended the investigation myself, and I vouch that nothing is concealed within this house.”

“Do you think that the assassin was actually in the house when we first entered?”

“That’s more than likely,” he answered with a pensive air. “Evidently the instant you’d gone the body of the fair-haired girl was somehow spirited away.”

“Where?”

“Ah, that’s what we must find out. Perhaps a taxi-driver will be able to throw a light upon the matter.”

“This is certainly a first-class mystery,” observed Dick, with journalistic instinct and a keen eye to those “special interviews” and “latest revelations” in which readers of his journal always revelled. “It will make no end of a stir. What a godsend, now that the gooseberry season is coming on.”

A good murder mystery is always welcome to a certain class of London daily journals, but more especially in the season when Parliament is “up,” the Courts are closed for the Vacation, and the well of sensations runs low. This season is termed, in journalistic parlance, “the gooseberry season,” on account of the annual appearance of the big gooseberry, that mythical monster of our youth, the sea-serpent, and the starting of the usual silly correspondence upon “Why should we live?” or some equally interesting controversial subject.

We were all held in blank astonishment at this latest development of the extraordinary affair. It had so many remarkable phases that, even to Boyd, one of the shrewdest officers of the Criminal Investigation Department, it was bewildering.

To me, however, the disappearance of that dead woman with the fair, pure face was the strangest of all that tangle of astounding facts. That face had impressed me. Its every feature had been riveted indelibly upon my memory, for it was a face which, in life, I should have fallen down and worshipped as an idol, for there was about it a purity and charm which must have been highly attractive, a vivacity in those eyes which, even in death, had held me spell-bound.

“I don’t see that we can do any more just now,” Boyd remarked in a business-like tone to his subordinate.

“You’ve seen the three cards which were beneath the plates on the dining-table?” I asked.

“Yes,” he responded. “There’s some hidden meaning connected with them, but what it’s impossible at present to guess. In order to prosecute our inquiries we must preserve secrecy. Nothing must be published yet. Indeed, Patterson, you’ll apply to the Coroner at once to take steps to withhold the real state of affairs from the public. If the assassins find that no hue and cry is aroused we may have a far better chance of tracing them, for they may betray themselves.”

“It’s a pity,” observed Dick, deeply disappointed. “A first-class sensation of this sort don’t occur every day. Why, it’s worth four columns if a line.”

“Be patient,” Patterson urged. “You shall have an opportunity of publishing it before long, and I’ll see that you are a long way ahead of your contemporaries.”

“Don’t let the news agencies have a word. They always try and get in front of us,” said Cleugh, whose particular antagonists were the Central News and the Press Association, which possess facilities for the collection of news and its transmission by wire to the various newspapers that form one of the most marvellous organisations in unknown London.

“Leave it to me,” said the inspector. “As soon as it’s wise to let the public know anything I’ll give you permission to publish. The Comet shall be first in the field with it.”

“Very well,” answered Dick, satisfied with Patterson’s answer. That officer had been prominent a few years before in the investigations relative to those mysterious assassinations of women in Whitechapel, and was very friendly with “the Comet man,” as Cleugh was termed in the journal which he represented.

Many were the suggestions we put forth as to how the bodies of the victims could have thus been changed, but no theory we could advance seemed likely to have any foundation in fact.

The mystery was certainly one of the strangest that had ever puzzled the crime investigators of London. The cause of its discovery was a most remarkable incident, and at every turn as the investigation proceeded mystery seemed to follow upon mystery, until the whole affair presented so many curious features that a solution of the problem seemed utterly impossible.

I bent beside the body of the woman who, reclining in the armchair with one arm fallen by her side, presented the appearance of one asleep. Her presence there was a profound enigma. A thought, however, occurred to me at that moment. The dining-table below had been laid for three. Perhaps she was the third person.

For the greater part of an hour we remained in that house of grim shadows discussing the various phases of the astounding affair, until at last, about eleven, we all left, two constables in uniform being stationed within. So secretly had this search been carried out that the neighbours, though, perhaps, puzzled by Patterson’s inquiries, entertained no suspicion of any tragic occurrence. In Kensington Road all the shops facing Upper Phillimore Place were closed save the tobacconist’s and the frequent public-houses, the foot passengers were few, and at that hour the stream of taxis with homeward-bound theatre-goers had not yet commenced. Market garden carts from Hounslow or Feltham, piled high with vegetables, rumbled slowly past on their journey to Covent Garden, and a few empty motor-buses rattled along towards Hyde Park, but beyond all was quiet, for that great artery of Western London goes early to rest.

At the police-station we took leave of Patterson and Boyd, and entering a motor-bus at Kensington Church, arrived at our chambers shortly before midnight.

“There’s something infernally uncanny in the whole business,” said the Mystery-monger as we sat smoking, prior to turning in. It was our habit to smoke and gossip for half an hour before going to bed, no matter what the time. Our talk was generally of “shop” events in our world of journalism, the chatter of Fleet Street intermingled with reminiscences of the day’s doings. Dick was sitting in the armchair reflectively sucking his eternal briar, while I sat at my table pondering over a letter I had found there on my return. It was from Mary Blain, for whom I had once long ago entertained a very strong affection, but who had since gone out of my life, leaving only a shadowy recollection of a midsummer madness, of clandestine meetings, of idle, careless days spent in company with a smart, eminently pretty, girl in blue serge skirt, cotton blouse and sailor hat. All was of the past. She had played me false. I was poor, and she had thrown me over for a man richer than myself. For nearly three years I had heard little of her; indeed, I confess that she had almost passed from my memory until that evening when I had sat awaiting Dick, and now on my return I opened that letter to discover it in her well-known, bold hand – the hand of an educated woman.

The letter, which had had some wanderings, as its envelope showed, and was dated from her father’s house up the river, merely expressed a hope that I was in good health, and satisfaction at hearing news of me through a mutual friend. Such a letter struck me as rather strange. I could only account for it by the fact that she desired to resume our acquaintanceship, and that this was a woman’s diplomatic way of opening negotiations. All women are born diplomatists, and woman’s wit and powers of perception are far more acute than man’s.

The letter brought back to me vividly the memory of that sweet, merry face beneath the sailor hat, the wealth of dark hair, the laughing eyes so dark and brilliant, the small white hands, and their wrists confined by their golden bangles. Yes, Mary Blain was uncommonly good-looking. Her face was one in ten thousand. But she was utterly heartless. I recollected how, when with her mother she had spent a summer at Eastbourne, what a sensation her remarkable beauty caused at Sunday parade on the Esplanade. She was lovely without consciousness of it, utterly ingenuous, and as ignorant of the world’s wickedness as a child. The daughter of a wealthy City man who combined company-promoting with wine-importing, she had from childhood been nursed in the lap of luxury, and being the only child, was the idol of her parents. Their country house at Harwell, near Didcot, was in my father’s parish, and from the time when her nurse used to bring her to the Rectory until that well-remembered evening when in the leafy by-lane I had for the last time turned my back upon her with a hasty word of denunciation, we had been closest friends. She had played me false. My hopes had been wrecked on Life’s strange and trackless sea, and now whenever I thought of her it was only in bitterness. I have more than a suspicion that old Mr Blain did not approve of our close acquaintanceship, knowing that I was a mere journalist with an almost untaxable income; nevertheless, she had continued to meet me, and many were the happy hours we spent together wandering through that charming country that skirts the upper reaches of the Thames.