Part + 

II + 

The Criminal + 

XIII + 

Enter Dr. Priestley + 

That eccentric scientist, Dr. Priestley, sat in his study on the Monday morning following the death of Mr. Copperdock, busily engaged in sorting out a mass of untidy-looking papers. Most of them he tore up and placed in the wastepaper basket by his side; a few he glanced at and put aside. The April sun lit up the room with a pale radiance, lending an air of Spring even to this dignified but rather gloomy house in Westbourne Terrace. + 

Dr. Priestley was thus engaged when the door opened and his secretary, Harold Merefield, came into the room. There was an air of heaviness about both men, the old and the young, as though the Spring had not yet touched them, and Winter held them still in its grip. One might have guessed that some absorbing work had monopolized their energies, leaving them no leisure for anything but the utmost concentration. And one would have guessed right. For the last six months Dr. Priestley had been engaged upon the writing of a book which was to enhance his already brilliant reputation. Its title was Some Aspects of Modern Thought, and in it Dr. Priestley had, with his usual incontrovertible logic, shattered the majority of the pet theories of orthodox science. It was, as the reviews were to say, a brilliant achievement, all the more entertaining from the vein of biting sarcasm which ran through it. + 

When Dr. Priestley settled down to writing a book, he concentrated his whole attention upon it, to the exclusion of everything else. He allowed nothing whatever to distract his mind, even for a few minutes. He lived entirely in his subject, refusing even to read the newspapers, except certain scientific periodicals which might happen to contain something relevant to the work he had in hand. As he expected his secretary to follow his example, it was hardly to be wondered at that both of them looked jaded and worn out. + 

“I took the manuscript to the Post Office myself, sir,” said Harold Merefield listlessly. “Here is the registration receipt.” + 

“Excellent, my boy, excellent,” replied the Professor, looking up. “So the work is finished at last, eh? I have been destroying such notes as we shall not require again. The rest you can file at your leisure. Dear me, you look as if you needed a change of occupation.” + 

He stared at his secretary through his spectacles, as though he had seen him that morning for the first time for many months. “Yes, I think we both need a change of occupation,” he continued. “I feel that I should welcome some enticing problem, mathematical or human. It is time we stepped from our recent absorption back into the world. Let me see. What is the date?” + 

“April 28th, sir,” replied Harold with a smile. He knew well enough that the Professor would have accepted any other day he chose to mention. + 

“Dear me! Then the world is six months older than when we retired from it. No doubt many interesting problems have arisen in the interval, but I fear that their solutions lie in other hands than ours. By the way, when does our friend Inspector Hanslet return from America?” + 

Harold turned to one of the big presses which lined the walls of the room, and took from it a folder marked “Inspector Hanslet.” He consulted this for a moment, then looked up towards his employer. “At the end of this month, sir. There is no definite date mentioned. I dare say he is in London already.” + 

“Perhaps so,” agreed the Professor. “It does not really matter. My thoughts turned to him naturally, as to one who has in the past supplied us with some very satisfactory problems. Well, we must be patient, my boy. I have no doubt that we shall very soon succeed in finding some congenial work with which to occupy our minds.” + 

He returned to the business of sorting his papers, while Harold sat down at the table reserved for his use, thankful to be able to do absolutely nothing for a few minutes. His idea of a change of occupation was not to plunge at once into some abstruse mathematical investigation which would involve him in the writing up of endless notes. If only Hanslet would come back and divert the Professor’s thoughts into some other channel! But of Hanslet, since he had departed for New York during the previous year to cooperate with the American police in running to earth a gang of international swindlers, nothing had been heard. + 

Inspector Hanslet was rapidly becoming the foremost figure at Scotland Yard. He was a man who, without being brilliant, possessed more than the usual quickness of perception. He could, in his own phrase, see as far through a brick wall as most people, and to this attribute he added an agility of mind remarkable in a man whose training had been of a stereotyped kind. Early in his career he had become acquainted with Dr. Priestley, and the Professor, to whom a problem of any kind was as the breath of his body, had since encouraged him to come to Westbourne Terrace and discuss his difficulties. To many of these the Professor’s logical mind had suggested the solution. Since he refused to allow his name to be mentioned, the credit for his deductions descended upon Hanslet. As a matter of fact, the authorities knew very well how matters stood, and Hanslet was always employed upon those cases which promised to be complicated, since it was an open secret that he could call upon the advice and assistance of Dr. Priestley. + 

It was evident that the sudden reaction of having nothing to do, after his unremitting labours of the past six months, was having an unfavourable effect upon Dr. Priestley’s temper. He roamed about the study, pulling out a file from time to time, and finding fault with Harold because some item did not come immediately to his hand. It was not until it was time to dress for dinner that he desisted from this irritating occupation. And even at dinner he was silent and morose, obviously seeking in vain for some new interest which should occupy his restless thoughts. But hardly had he and Harold finished their coffee, which they always had in the study after dinner, than Mary the parlourmaid opened the door softly. “Inspector Hanslet to see you, sir,” she announced. + 

The Professor turned so abruptly in his chair as seriously to endanger the coffee cup he was holding. “Inspector Hanslet!” he exclaimed. “Why show him in, of course. Good evening, Inspector, it was only this morning that Harold and I were speaking of you. I hope that you enjoyed yourself in America.” + 

“I did indeed, Professor,” replied Hanslet, shaking hands warmly with Dr. Priestley, and nodding cheerily to Harold. “Not that I’m not very glad to be home again; one’s own country’s best, after all. I landed at Southampton last Wednesday.” + 

“And now you have come back to tell us of your experiences,” said the Professor. “I am sure we shall be most interested to hear them. Did you succeed in your object?” + 

“Oh, yes, we rounded them up all right,” replied Hanslet. “My word, Professor, you ought to go over to New York and see the things the fellows do over there. As far as scientific detection goes, they’ve got us beat to a frazzle. You’d appreciate their methods. And they’re a cheery crowd, too. They gave me no end of a good time while I was over there.” + 

“Well, sit down, and tell us all about it,” said the Professor, motioning Hanslet towards a comfortable chair. “You will relieve the tedium I am feeling at having nothing to do.” + 

Hanslet sat down, and, as he did so, looked enquiringly at the Professor. “You say you’ve nothing to do, sir? Well, I’m very glad to hear that. The truth is that I didn’t come here to tell you my experiences. As a matter of fact, I meant to take a month’s leave when I got back, but the Chief asked me to wait a bit and take over a case which has been puzzling the Yard for several months. And I wanted to ask your advice, if you would be good enough to listen.” + 

The Professor rubbed his hands together briskly. “Excellent, excellent!” he exclaimed. “I told you this morning, Harold, that a problem was bound to turn up before long. By all means tell me your difficulties, Inspector. But let me beg of you to keep to facts, and not to digress into conjecture.” + 

Hanslet smiled. The Professor’s passion for facts was well-known to him from past experience. “Well, I expect you know as much about it as I do,” he began. “Ever since Tovey the greengrocer was killed last November, there’s been a lot in the papers⁠—” + 

But the Professor interrupted him. “I should perhaps have explained, Inspector, that since last October I have scarcely opened a newspaper. My whole mind has been concentrated upon a task which is now happily finished. The name of Tovey the greengrocer is, I regret to say, utterly unfamiliar to me. I should be glad if you would treat me as one who has only lately reached this world from the planet Mars, and give me the facts without presuming that I have any previous knowledge of them.” + 

“Very well, Professor,” replied Hanslet. “You must have heard of a series of deaths under peculiar circumstances which have occurred in Praed Street, not half a mile away from here? Why, I read about them in New York! They caused a great sensation.” + 

“I am not concerned with popular sensations,” said the Professor coldly. “I admit that some rumours of such happenings penetrated the isolation with which I have endeavoured to surround myself, but I dismissed them from my mind as likely to introduce a disturbing factor. I repeat that you had better repeat the facts, as briefly as possible.” + 

“Very well, Professor, I will tell you the story exactly as it was told to me at the Yard,” replied Hanslet. “You will be able to see how much is fact and how much conjecture. As I was not on the spot myself, I cannot vouch for the details. Will that do?” + 

The Professor nodded, and turned to Harold. “Make a note of the names and dates mentioned by Inspector Hanslet,” he said. “Now, Inspector, you may proceed.” + 

Hanslet, whose memory for names and facts was rarely at fault, recounted as briefly as he could the course of events from the murder of Mr. Tovey in November, to the finding of Martin’s body in the cellar of Number 407, in January. The Professor interrupted him now and then to ask a question, but in the main he allowed him to tell the story in his own way. When he had finished, and the Professor had expressed himself satisfied, Hanslet continued. + 

“The man who’s been in charge of the case is a fellow called Whyland, keen enough on his job, but a bit lacking in imagination. I had a chat with him yesterday, and he confessed that he was completely at the end of his tether. Up till last Saturday evening, he told me, he was pretty sure that he could lay his hand on the criminal, but that night something happened which entirely upset his calculations.” + 

“What was that?” enquired the Professor, who was listening intently. + 

“Why, for one thing, the man whom he suspected of the murders has been killed,” replied Hanslet. “Not that there was anything amazing in that, for he seems to have been a trifle unbalanced in any case, and his death may possibly have been due to suicide. No, what altogether upset Whyland’s applecart was that another man received a counter, some time after the death of the man whom Whyland suspected of delivering them.” + 

“It is remarkable how frequently hypotheses founded upon pure conjecture are upset by one simple fact,” remarked the Professor acidly. “Now, what was the name of this man whom Whyland suspected, and who so inconsiderately spoilt the theory by his premature death?” + 

“Samuel Copperdock,” replied Hanslet, turning to Harold, who wrote the name on his pad. + 

“Copperdock?” repeated the Professor. “An unusual name, and yet I seem to have heard it before in some connection. Copperdock, Copperdock! Let me think⁠—” + 

“You’ve probably seen the name above his shop, Professor,” said Hanslet. “He was a tobacconist in Praed Street. Or you may have seen it some months ago in the paper. He was a witness at the inquest on Tovey, who was the first man murdered.” + 

But the Professor shook his head. “No, if my memory serves me, I heard the name many years ago, in some connection which escapes me for the moment. However, the point would not appear to have any importance. I must apologize for interrupting you, Inspector. You were saying that another man received a counter after this man Copperdock’s death, but I do not think you mentioned his name?” + 

“Ludgrove. Elmer Ludgrove,” said Hanslet. “Rather an interesting personality, from what Whyland tells me. He keeps a herbalist’s shop, and is a bit of a character in his way. He’s a man of some education, between fifty and sixty, a very dignified old boy with a striking white beard, which I expect is a bit of an asset in his trade. He doesn’t say much about himself, but does a lot of good in his own quiet way. All the poorer people in the neighbourhood come to him if they’re in any sort of trouble, and he freely admits he hears a good many secrets. Whyland thought he would be a useful chap to get on the right side of, and often used to drop in to see him. He says he got more than one valuable hint from him. He was also pretty certain that this chap Ludgrove shared his suspicions of Copperdock, but he would never say so outright. You see, Copperdock was a friend of his.” + 

The Professor nodded. “I see,” he said. “And it was this Mr. Ludgrove who received the counter you say?” + 

“Yes, and, what’s more, Whyland was with him when he found it. The poor old boy was terribly shaken for the moment, Whyland says, but after a bit he pretended to treat it as a joke. I’ve seen him since, and he’s pretty plucky about it, knowing as he does that everybody who has received one of these infernal numbered counters has died a sudden death. He says that he is an old man, anyhow, alone in the world and with only a few more years to live in any case, so that his death will be no great blow to anybody.” + 

“A most philosophic attitude,” agreed the Professor. “But to return to Mr. Copperdock, I should like to hear the circumstances under which he met his death.” + 

Hanslet related the events of the previous Saturday night in considerable detail, up to the time when Whyland and Ludgrove entered the latter’s sanctum. “There’s not much more to add,” he continued, “except that the doctor’s suspicions were confirmed as to the poison. The Home Office people examined the fragment of broken needle, and I heard this afternoon that they found traces of a remarkable virulent synthetic alkaloid. You’ll know what that is better than I do, Professor.” + 

“Yes, I know,” replied the Professor grimly. “I have reason to. It was with one of these synthetic alkaloids⁠—there are a number of them⁠—that Farwell tipped the spines of the hedgehog to which I so nearly fell a victim. You remember that incident, I dare say?” + 

“I do, indeed,” said Hanslet warmly. “What’s more, the Home Office people say that a dose of the stuff would produce almost immediate paralysis, and death within a few minutes. The incrustation was potassium carbonate all right, almost certainly the result of putting caustic potash on the place. But that only makes the business more puzzling. If Copperdock poisoned himself, how did he have time to apply the caustic potash before he was paralysed? If someone else did it, why should they apply the caustic, and how did they get in and out of the house? Remember, Whyland’s man Waters had the place under observation all the time.” + 

“Then you are inclined to favour the theory of suicide?” asked the Professor. + 

“On the whole, yes,” replied Hanslet. “Oh, by the way, I forgot to tell you that soon after daylight Waters found the syringe, with the other part of the needle still in it, by the side of the road under Copperdock’s window. There had been a heavy shower of rain about half past three, and the syringe was covered with mud and filth. The analysts could not find any traces remaining of the poison, but the end of the needle proved that it was the one that had been used. That points to suicide, a murderer wouldn’t chuck away his weapon like that where anyone could see it. + 

“Besides, if you come to think of it, suicide fits in best with what we know. It is a fact that Copperdock’s mind was to some extent unhinged. He declared that he met the black sailor, when a reliable witness declares that no such person was about. In fact, the only person besides Copperdock who seriously claims to have seen this black sailor is a degenerate youth who is also a convicted pickpocket. It is highly probable that the counters were numbered, and the envelopes containing them typed in Mr. Copperdock’s office. Whyland assures me that the only link between the victims was Copperdock, not in any definite form, certainly, but still definite enough to make the coincidence remarkable. I am inclined to believe that Copperdock was at the bottom of it all somehow. My difficulty will be to prove it.” + 

“You think, I gather, that this Mr. Copperdock suffered from a peculiar form of homicidal mania, which finally culminated in his taking his own life?” suggested the Professor. “I admit that such cases are not unknown, but the theory involves you in many difficulties. I mention only one of them, the first that occurs to me. Where did he obtain this synthetic alkaloid? These substances are not articles of commerce, they are not, so far as I am aware, used in medicine. They are only produced experimentally in research laboratories. Farwell had a well-equipped laboratory, as you probably remember, which accounts for his use of such a poison. But how could a man in Copperdock’s position procure it?” + 

Hanslet shrugged his shoulders. “I don’t know, Professor,” he replied. “I confess that I turn to the theory of Copperdock as the murderer because it seems to present fewer difficulties than any other. The whole thing seems to me to involve a mass of contradictions, whichever way you look at it. It’s for that very reason I came to see you, Professor. But you must at least admit that madness in some form must be responsible. What rational motive could there be for the murder of half a dozen men entirely unconnected with one another, and whose deaths could be of no possible benefit to the murderer?” + 

“I am prepared to admit nothing until I have further examined the facts,” replied the Professor severely. “Now, Harold, will you read me your notes upon the first murder? Thank you. I should like all details relating to Mr. Tovey, please, Inspector.” + 

It was long past midnight before they reached the end of the catalogue, and the Professor was satisfied that he knew everything which Hanslet could tell him. + 

“You will, of course, let me know if any fresh facts come to light,” he said, as Hanslet rose to take his leave. “Meanwhile, I will consider the matter. If I come to any definite conclusions I will let you know. Good night, and pray accept my most sincere thanks for presenting me with a most absorbing problem.” + 

XIV + 

The Morlandson Trial + 

The Professor came down to breakfast next morning looking even more weary than on the previous day. Harold, looking at him anxiously, guessed that he had hardly slept at all during the night. Some absorbing train of thought, whether started by Hanslet’s story of the previous evening or not, had taken possession of his brain. But, in spite of his weariness, there was a queer gleam in the piercing eyes behind the powerful spectacles, which Harold knew from past experience to be the light of battle. + 

“I have some work for you today, my boy,” he said, as soon as the meal was over. “I want you to go to the British Museum and look up the reports of the trials for murder at the Old Bailey during the first ten years of the present century. Among them you will find the trial of a doctor for the murder of one of his patients by giving him an overdose of morphia. I believe that the doctor’s name began with an M, and I fancy that his patient had a title. More than this I cannot tell you, my memory, I regret to say, is not what it used to be. I want you to make a précis of that trial and of the sentence.” + 

“Very good, sir,” replied Harold, and forthwith started on his quest. He could not guess the purpose for which the Professor required this information, but it could obviously have nothing to do with these intriguing murders in Praed Street which Hanslet had described. Unless, perhaps, the Professor had seen some parallel between the methods of the unknown criminal and those of this vague doctor whose name began with an M. You never could predict the direction from which the Professor would approach a problem. All that you could be certain of was that it would be different from the one you anticipated. + 

Arrived at the Museum, where he was a frequent visitor on similar errands, he went carefully through the index to the Law Reports. It was not until he came to the year 1906, that he met with anything which corresponded to the data which the Professor had given him. Then he found a reference to the trial of one Doctor Morlandson for the murder of Lord Whatley. This must be the case to which his employer had referred. He turned up the records, and proceeded to make a careful abstract. + 

It appeared that Lord Whatley had been a man of middle age, and of some considerable wealth. Dr. Morlandson was his regular medical attendant, and in 1905 he had been compelled to warn his patient that he was suffering from cancer, and that though an operation might be successful, there was grave doubt that it would permanently remove the source of the trouble. However, Lord Whatley consented to undergo the operation. He was removed to a nursing home, and a specialist was called in. The patient went through the ordeal satisfactorily, and after a while he returned home. + 

But, by the beginning of the following year, the symptoms reasserted themselves, and Dr. Morlandson informed his patient, who insisted that he should be told the truth, that nothing more could be done, and that Lord Whatley had nothing to look forward to but perhaps a year or two of suffering. The relations between the two men were rather those of close friendship than of doctor and patient, and, subsequent to Dr. Morlandson’s pronouncement, they saw a great deal of one another. Morlandson devoted as much time as he could spare from his practice to sitting with Lord Whatley, who was a childless widower and did not encourage the visits of his friends and relations. + 

By the end of February it appeared that the disease was progressing even more rapidly than Dr. Morlandson had anticipated. He administered frequent injections of morphia, and his patient was rarely conscious. Morlandson continued to spend the greater part of his time with him, and in Lord Whatley’s brief intervals of consciousness his doctor, and the nurses who had been called in, were the only people he spoke to. + 

He died early in March, in the presence of Dr. Morlandson and one of the nurses, without regaining consciousness. A cousin of Lord Whatley’s, who happened to be his nearest relative, was in the house, and Morlandson informed him that he would return home and bring the necessary certificate with him later in the day. Morlandson, who lived about a mile away, started to walk home. When he had almost reached his own house, he heard a sound of confused shouting, and saw a runaway horse attached to a milk-cart, coming towards him. Without a moment’s hesitation he rushed for the horse’s head, and had almost succeeded in stopping him, when he slipped and fell. One of the horse’s hoofs struck him on the head and he was left unconscious on the road. + 

The spectators of the accident picked him up, and he was carried into his own house. A colleague was summoned, and declared that he was suffering from severe concussion. This diagnosis proved correct, and Morlandson lay in a state of semiconsciousness for nearly a week. On his recovery, he found the house in possession of the police. + 

Lord Whatley’s cousin, hearing of the accident to Dr. Morlandson, and learning that he could not possibly attend to his duties for some time to come, was at a loss for the want of a death certificate. He therefore sent for another doctor⁠—not the man who was attending Morlandson⁠—and asked him to sign the certificate. This the doctor would have done, had not one of the nurses, whom Morlandson had reprimanded for some breach of duty, made some vague insinuation that everything was not as it should be. The doctor insisted upon examining the body, and as a result of this examination he communicated with the authorities. A postmortem was held, and Lord Whatley was proved to have died of an overdose of morphia. The experts gave it as their opinion that the deceased would not have died of the disease from which he was suffering for another year at least. A warrant was immediately issued for Dr. Morlandson’s arrest. + 

When Lord Whatley’s will came to be read, it was found that he had left the sum of ten thousand pounds to Morlandson, conditional upon his being his medical attendant at the time of his death. This bequest was contained in a codicil executed early in February. + 

Morlandson came up for trial at the Old Bailey in July. The prosecution alleged that the codicil disclosed the motive for the murder, and submitted that Morlandson, fearing lest Lord Whatley should change his doctor before he died, had made certain of securing the legacy by poisoning him. They pointed out that, but for Morlandson’s accident, he would have been able to certify cancer as the cause of Lord Whatley’s death, and no suspicion would have been aroused. + 

Dr. Morlandson’s counsel put in a very striking defence. In effect, he pleaded guilty to the act of poisoning, but affirmed that this was done at Lord Whatley’s express command. He had already suffered considerably and undergone an ineffectual operation, and refused to contemplate the further agony to which he was condemned. As soon as Morlandson had informed him that his case was hopeless, he had begged him to put a end to his sufferings at once, pointing out that such a course would cause no grief or inconvenience to anyone. Morlandson had at first refused, but at last, upon the solemn assurance of Lord Whatley that he would find some means of committing suicide unless his wishes were complied with, he consented to inject morphia in increasing doses. This Lord Whatley agreed to, and whenever he was conscious Morlandson begged him to reconsider his determination. Finally, knowing that the disease was incurable, and that the man he cared for as his friend could only endure months of suffering under his very eyes, he bade him farewell and administered the fatal dose. The news of the bequest came as a complete surprise to him. + 

Morlandson’s defence raised in an acute form a controversy which had been going on for many years. Many people held that he was completely justified in his action, that his offence was purely technical, and that at the most it merited a short term of imprisonment. But the jury, in spite of a hint from the judge, found Morlandson guilty of murder and refused to add a rider recommending him to mercy. Sentence of death was duly pronounced, but the Home Secretary, the Court of Criminal Appeal not being then in existence, ordered a reprieve, and the sentence was commuted to one of twenty years’ penal servitude. Morlandson’s wife, to whom he was deeply attached, died before a year of it had expired. + 

This was the substance of the notes which Harold Merefield brought back to Dr. Priestley. The latter read them through carefully, then gave them back to his secretary. “Yes, I thought that I was not mistaken,” he said. “The facts of the case come back to me very clearly now. It made a considerable sensation at the time, owing to the principle involved. Right or wrong, Morlandson was acting in accordance with his lights. His evidence, I remember, was given with an air of passionate conviction. This Lord Whatley was his friend, and he had saved him from suffering at the expense of twenty years of his own life. I wonder whether he survived his sentence? It would be most interesting to learn.” + 

The Professor relapsed into his favourite attitude of thought, his eyes fixed upon the ceiling, his hands, with the tips of the fingers touching, laid upon the table in front of him. He remained like this for many minutes before he spoke again. + 

“It would be so interesting that I feel impelled to take steps to discover the facts,” he said. “After lunch I shall visit the record department of Scotland Yard. While I am away, you can complete the filing of those papers I gave you yesterday, relating to the work which we have just completed.” + 

Harold received these instructions without any great enthusiasm. He was not greatly interested in the case of this Dr. Morlandson, since it had occurred so many years ago and could have no possible bearing upon any problem of the present day. In his recollection of this forgotten trial the Professor seemed to be neglecting entirely the problems presented by the murders in Praed Street. Perhaps he had decided that they were not worthy of his notice. It was not every problem submitted to him which appealed to him sufficiently to induce him to devote his energies to its solution. + 

He spent the afternoon in the study, working half-heartedly and awaiting the Professor’s return. But it was not until nearly dinnertime that his employer came in, and then he could see by his expression that the result of his search had in some way disappointed him. Dinner was passed in almost complete silence, and the two returned once more to the study. + 

“I have discovered the subsequent history of Dr. Morlandson,” announced the Professor abruptly, as soon as he had finished his coffee. “I will recount to you the result of my researches at Scotland Yard. You can make notes of them, and file them with your précis of his trial.” + 

Harold produced pencil and paper, and the Professor proceeded to give an account of how he had spent the afternoon. After some delay the authorities at Scotland Yard, who were always anxious to carry out any of Dr. Priestley’s requests, even though they were ignorant of the motive behind them, had found the record of Morlandson’s career after his sentence. He had been sent to Dartmoor, and had served his time there. He had been released on licence in 1920, having undergone fourteen years of his sentence. He had then remained for a short time in London, arranging his affairs, but had not communicated with anybody but his solicitor, to whom he had expressed his intention of spending the rest of his life in the most complete seclusion, and devoting himself to chemical research, for which he had always had a bent during the period in which he was in practice. + 

Before the catastrophe which had overtaken him, Morlandson had been a tall, spare man, clean-shaven, and with carefully brushed dark hair. Upon his release he had developed a slight stoop, and although he was still clean-shaven and smart in his appearance, his hair had gone nearly white. He told his solicitor that he knew he had only a few years longer to live, but that he hoped that during that period his researches would confer some benefit upon suffering humanity. He proposed to commence them as soon as he could find a suitable spot for the purpose, where he could live entirely alone. + 

A few weeks after his release, he found a half-ruined cottage which answered to his requirements, situated in a peculiarly desolate part of the Isle of Purbeck, in Dorsetshire. He took up his residence here, repaired the cottage, and added to it a laboratory, built of concrete. Under the terms of his licence he was compelled to report to the police, and they kept an eye upon his movements. They might have saved themselves the trouble. Once he was established in his cottage, his furthest excursion was to Corfe Castle, the nearest town, to obtain supplies. He lived entirely alone, and invariably walked across the heath to and from his cottage. But, even while living this hermit existence, he was always carefully dressed and shaved. He made no attempt to conceal his identity, but called himself Mr. Morlandson, having dropped the prefix “Doctor.” He had, of course, been struck off the register, and could not have practised as a doctor even had he desired to do so. + 

The local superintendent to whom he reported conceived a liking for him, and occasionally walked across the heath to visit him. He invariably found him at work in his laboratory, which was plentifully stocked with chemicals of various kinds. He would never allow smoking in the laboratory, for, as he pointed out to the superintendent, the substances with which he was experimenting were highly inflammable, and there was consequently grave risk of fire unless proper precautions were taken. + 

One night, rather more than a year after Morlandson’s release, flames were seen from Corfe Castle across the heath in the direction of his cottage. The superintendent leapt on his bicycle, and dashed off to the scene. When he arrived, he found the laboratory burning like a furnace, and quite unapproachable. The flames had caught the cottage, which was by then past saving, especially as the only available water supply was from a well fitted with a small bucket. The superintendent, at considerable risk to himself, managed to enter the sitting-room of the cottage, but could see no trace of Morlandson. + 

By morning the fire had burnt itself out. The cottage had been completely destroyed, only two or three feet of the outer walls remaining. The laboratory, being built of concrete, had fared rather better. The greater part of the walls remained, as did the steel door, which formed the only entrance. The place had no windows, but had been lighted from above through skylights in the roof. These and the roof itself had completely disappeared. The iron door was found to be locked upon the inside. + 

When it had been broken down, the interior of the laboratory showed how fierce the fire had been. Every trace of wood had been consumed, and solid metal fittings had been melted into unrecognizable shapes. Among the debris on the floor lay a charred human skeleton, upon one of the fingers of which was a half-melted gold ring, of which enough remained for the superintendent to identify it as having been habitually worn by Morlandson. The remains of the unfortunate man were huddled up by the door, the key of which was in the lock. It was clear that Morlandson had tried to make his way out when the fire broke out, but had been overcome by the fumes of the burning chemicals before he could achieve his purpose. He had been in the habit of locking the door in order to secure himself from interruption. + 

“You have made notes upon this?” asked the Professor. “Good. File them away. I confess that there are many things about this man Morlandson which I do not yet understand. I was able to supplement your account of the trial by an examination of the original records, which I was allowed to make. These gave me considerable food for thought. I believe that, through a pure accident, I have stumbled upon one of the most curious occurrences of modern times. I can, as yet, only conjecture, and so far my conjectures are wholly unsupported by fact. Much research will be necessary before these facts can be established, and it is possible that I may not be spared for a sufficient time to carry out this research.” + 

“Not be spared, sir!” exclaimed Harold, startled by the grave tone of the Professor’s voice. “Why, you have many years before you yet, I hope.” + 

“Death comes to us all, sooner, perhaps, than we expect,” replied Dr. Priestley. “And I feel, this evening, that death may be closer to me than I have supposed. Ah, do I hear someone in the hall?” + 

With a nervous movement, entirely foreign to him, Dr. Priestley rose from his chair and stood facing the door. Harold, with a queer feeling of expectation, walked towards it and opened it. In the hall stood Inspector Hanslet, handing his coat and hat to Mary. + 

“Good evening, Mr. Merefield, I thought I’d look round and see if the Professor had any information for me,” he said. “May I see him?” + 

“Yes, come in by all means,” replied Harold, with a sudden sense of relief. “But I shouldn’t stay too long, if I were you. He’s rather tired and nervy tonight.” + 

Hanslet nodded, and Harold led the way into the study. “It’s Inspector Hanslet, sir,” he said. + 

The Professor appeared to have entirely recovered his usual equanimity. “Ah, good evening, Inspector,” he said blandly. “I half expected that you would be round this evening. I am very glad to see you.” + 

“I thought I would come round, on the chance that you had some hint to give me,” replied Hanslet. “I can’t make head or tail of the business I told you about last night. The more I think about it, the more puzzling it seems. It’s the utter lack of motive that makes it all so inexplicable.” + 

“I believe, mind, I say only that I believe, that I have discovered the motive,” said the Professor quietly. + 

“You have!” exclaimed Hanslet excitedly. Then, seeing the slow movement of the Professor’s head, he smiled. “I know you won’t tell me until you are certain,” he continued. “But at least tell me this. Are there likely to be any more of these mysterious deaths?” + 

“There will be one more, unless I am able to prevent it,” replied the Professor. + 

XV + 

The Bone Counters + 

Mr. Ludgrove, as Hanslet had said to Dr. Priestley, bore the shock of the finding of the numbered counter extremely well. He had refused to make any alteration in usual habits, and it was with the greatest difficulty that Whyland could persuade him to allow a constable to sleep in the house at night. + 

“I can assure you that this mysterious warning does not terrify me,” he had said. “I am an old man, and death cannot be far off in any case. I am not sure that I should not prefer a violent end to some lingering illness which might leave me helpless for months before it killed me. But, if you think that by keeping a close watch over me you can gain some clue to the distributor of these counters, by all means do so.” + 

He was in this frame of mind when Hanslet came to see him on the Sunday afternoon. Whyland brought him round and introduced him, and Mr. Ludgrove welcomed him with his usual courtesy. + 

“I have heard of you, Inspector Hanslet, and I am indeed proud to make your acquaintance. Sit down, and make yourself comfortable.” + 

“Thank you, Mr. Ludgrove,” Hanslet replied. “I thought you wouldn’t mind my coming to have a chat with you. Whyland here has told me all about these queer happenings in this street of yours, and of the help which you have been to him.” + 

“I am afraid that I have been of very little help,” said Mr. Ludgrove with a smile. “Inspector Whyland has been kind enough to appreciate beyond their value any suggestions I have made.” + 

“Well, that’s as may be,” replied Hanslet. “Now, Mr. Ludgrove, I am going to ask for further assistance on your part. You know as much about these counters as I do. They seem to have been sent, so far, to six men, all of whom have died shortly after they received them. Whyland tells me that he has utterly failed to establish any connection between these men. Except for the fact that Tovey and Copperdock were close friends, they all seem to be comparative strangers to one another, and have never been associated in any common enterprise. You see what I mean, of course?” + 

“I do, indeed. In fact, Inspector Whyland and I discussed the point, long ago. It might be possible to imagine a motive for the murder of a group of men who were inspired by a common motive or who belonged to some common society. The difficulty is, assuming that the agency which compassed their deaths was the same in each case, to imagine a motive for the actions of that agency.” + 

“Exactly!” exclaimed Hanslet warmly. “I see that you appreciate my point as clearly as I do myself. But now we have a fresh line of investigation. You yourself are added to the list of those who have received the counter. Can you explain why you should have been singled out?” + 

Mr. Ludgrove shook his head. “As you may suppose, the subject has occupied my thoughts ever since I found the counter,” he replied. “I am an old man, as I have said before, and for the last twenty years or more I have led a retired life, retired, I mean, in the sense that I have taken no part in the affairs of the world. I have had enemies as well as friends; few men who have reached my years could say otherwise. But most of the contemporaries of my youth are dead, and in any case I do not believe that any of the enemies I may have made would be so vindictive as to seek my life.” + 

“Let us look at it another way, then,” said Hanslet. “Can you imagine any way in which you, in common with the six men who have already died, could have made an unconscious enemy?” + 

“I cannot,” replied Mr. Ludgrove. “Of those six men, I knew only two personally, Mr. Copperdock fairly well, and Mr. Colburn slightly. Both of these I have known only since I came to live in Praed Street, five years ago. Tovey, I had heard Copperdock speak of. The name of Richard Pargent, I had seen mentioned in the newspapers. The other two were complete strangers to me. I cannot imagine how we could have committed any act in common which would draw down upon us the vengeance of a single assassin.” + 

“Then you do not believe that these deaths are the work of a single assassin, Mr. Ludgrove?” enquired Hanslet with interest. + 

“Not of a single man, acting upon any rational motive,” replied Mr. Ludgrove. “Even in the brain of a homicidal maniac there is usually traceable some dim guiding principle. He either conceives a hatred for a certain class of person, or he kills indiscriminately, usually selecting the people nearest to hand. In this case the selection was anything, but indiscriminate. Mind, I am assuming for the moment, as apparently you are yourself, that the death of all six was the direct sequel of their receipt of a numbered counter. If you adopt the theory that a single man is responsible, you may as well believe in the existence of the black sailor.” + 

“I am afraid that we are already committed to him,” said Hanslet with a smile. “You see, we offered a reward for him, and it would never do for the police to admit that they had offered a reward for a ghost. Whyland, what is your honest opinion of this black sailor?” + 

“Entirely between ourselves and this most comfortable room, I have never believed in his existence for a moment,” replied Whyland readily. “But what could I do? That young rip, Wal Snyder, swore to having seen him, and I couldn’t shake him.” + 

“Whether young Snyder saw him or not,” remarked the herbalist, “your reward has made him a very real person to the poorer classes of this district. One or other of my customers sees him every night, usually during the hour which immediately follows the closing of the public houses. And, as a rule, they come here hotfoot to tell me about it.” + 

“I’m sorry, Mr. Ludgrove,” laughed Whyland. “I wouldn’t have done it if I could have helped it. By the way, I suppose that you are perfectly satisfied that none of these odd customers of yours know anything about this business?” + 

“Perfectly,” replied Mr. Ludgrove. “They are a strange lot, I admit, professing a code of morals which in some respects would shock the conscience of a savage, and many of them are not above any petty dishonesty. But murder, deliberate and planned murder, that is, is outside their imagination. Besides, the way they know one another’s most secret actions is almost uncanny. If one of them knew anything about these deaths, they would all know within a very short time, and the secret would be a secret no longer. Of course, they all come to me with long and complicated tales of how they could tell me the name of the man who did it, if I will give them the money in advance. But I am well accustomed to that, it is a symptom which follows every crime committed in this district.” + 

“You’re quite right, Mr. Ludgrove, I know something of the ways of these people,” said Hanslet. “When they talk like that, you may be sure that they know nothing. It’s when they avoid the subject that you may learn something. Well, I’m very glad to have met you. There’s just one thing I should like to say. You have received this counter, which was evidently slipped in here while all of you were thinking of nothing but the death of Mr. Copperdock. You, and those whose business it is to guard you, are therefore forewarned. As long as you do what we ask you to, I do not believe that you are in any danger.” + 

Mr. Ludgrove smiled. “Mr. Copperdock was also guarded and forewarned,” he said quietly. + 

Whyland swore softly. “I believe Copperdock committed suicide out of sheer funk,” he said. “Anyhow, I can’t see any way in which he can possibly have been murdered.” + 

“Well, I shall not commit suicide just yet, I promise you that,” replied Mr. Ludgrove. + 

It was not more than five minutes after the departure of Hanslet and Whyland that the herbalist heard a soft knock upon the door of the shop. He went to open it, and found Ted and Ivy standing on the step, closely scrutinized by the man in plain clothes who had been deputed to look after Mr. Ludgrove’s safety. + 

Mr. Ludgrove glanced at Ivy, and welcomed Ted warmly. “Come in,” he said hospitably. “I was going to look in later and ask you if you would care to spend the evening here. I am very glad you came over.” + 

“Thank you, Mr. Ludgrove,” replied Ted awkwardly. “This is Miss Tovey. You have heard poor Dad and me mention her.” + 

“I have indeed. I am very glad to meet you, Miss Tovey. I think that is the best chair. Won’t you sit down and make yourself comfortable?” + 

The young people sat down in silence. It was evident that they had come with a purpose, but now they had arrived they did not quite know how to state it. Curiously enough, it was Ivy who made the plunge. + 

“I’ve heard so much about you, Mr. Ludgrove, that I felt that Ted and I simply must come and ask your advice,” she began. “We both feel we must do something. First of all my father is murdered, and now Ted’s. We just can’t sit still and wait any longer. Mr. Ludgrove, can’t something be done to punish the man?” + 

The herbalist looked at her gravely. “My dear young lady, I sympathize with you entirely,” he said. “I, too, have felt the desire to do something in the face of these extraordinary happenings. But let me assure you that the very best brains in the police are at work in the matter. Inspector Hanslet, who was here just now, has the matter in hand, and he has unravelled almost as tangled skeins as this appears to be.” + 

“That was Inspector Hanslet, was it?” enquired Ted, with interest. “We saw two men, one of whom we knew was Inspector Whyland, come in to see you, and we waited until they went away. I’ve heard of Inspector Hanslet before, seen his name in the papers, often enough. I’m glad he’s on the job, I shall feel that something’s being done at last. The other chap always seemed to be hanging round the poor old Dad, and doing nothing.” + 

“It is very difficult for the police to do anything without evidence,” said Mr. Ludgrove gravely. “Now, since you have come to ask my advice, I am going to take an old man’s liberty and ask you both a question which you may consider impertinent. Have either of you any knowledge, concerning your dead parents, which you have not imparted to the police? Or, perhaps, I should have put it another way. Have either of you any suspicions, which you have thought it better to keep to yourselves, as to the motive which anyone might have had for committing these murders?” + 

He looked at Ivy as he spoke, but she shook her head emphatically. “I can think of nothing which I have not already told Inspector Whyland,” she replied. “Daddy was a dear, and I don’t believe he had an enemy in the world,” she replied. “He was a little hot-tempered at times, but everybody knew that he meant nothing by it.” She paused for a moment, then continued with downcast eyes. “I can imagine what may have passed through your mind, Mr. Ludgrove, but Daddy wasn’t that sort of man. I won’t say that he was above a mild flirtation, but I am sure that no woman was the cause of his being murdered.” + 

“Thank you, Miss Tovey,” replied the herbalist gravely. “That is a franker statement than I had any right to expect. And you, Ted?” + 

“No, I’ve told the police everything,” replied Ted wearily. “I know they think that Dad committed suicide. I believe they want people to think so, so that there won’t be another undetected murder up against them. But I know he didn’t. Dad wasn’t the sort of man to do a thing like that. I know he got a bit tight sometimes, but why shouldn’t he? It never did him or anybody else any harm. But even when he was tight he never got morbid, like some fellows do. Besides, he never used one of them syringe things. I don’t suppose he’d ever seen one in his life, and he wouldn’t know how to use it. No, Dad was murdered, right enough, though I’m blest if I can see how it was done.” + 

“Can’t you help us, Mr. Ludgrove?” broke in Ivy. “Surely there must be some way of finding out who killed Daddy and Ted’s father. It must have been some lunatic, for no sane person could possibly have a grudge against either of them.” + 

“The only way to find out seems to be to learn something about these counters,” replied Mr. Ludgrove. “Your father, I am told, received the first. Did you see it, Miss Tovey?” + 

“No. I only know what mother told me,” replied Ivy. “Daddy was a bit late coming back from Covent Garden that morning, and I had finished my breakfast and gone to work before he came in. Of course, he had no idea what it meant, poor dear. He thought it was one of these advertising dodges, and threw it into the fire, envelope and all.” + 

“Well, that is a pity,” said Mr. Ludgrove. “The police have seen all the others, and they say that they are all exactly similar, and that the numbers seem to have been written on them with the same pen and ink, just an ordinary steel pen and red ink that one can buy at any stationer’s. And, whenever they have been sent by post, the envelopes have been of the same sort, the address typed with the same machine, a Planet, and posted in this district, London, W.2. This looks as though they had been sent out by the same hand.” + 

“Typed on a Planet, were they?” remarked Ted. “That’s the same machine as we’ve got.” + 

“Yes, it is a fairly popular make, I am told,” replied Mr. Ludgrove. “But I have never used a typewriter in my life, and know very little about them. No doubt Miss Tovey can tell us if Planet machines are used extensively?” + 

“I had never used one until Ted asked me to teach him to use his, nearly a year ago now,” replied Ivy. “There were none at the school I was at, and we haven’t any at the office. But I believe that some firms have several of them. They have not been sold in England for very long.” + 

“Thank you, Miss Tovey,” said Mr. Ludgrove. “Now there is another curious thing which I should like to mention. One day, when I was in your place, talking to your father, I saw you sending out what I took to be accounts, Ted. Was I right?” + 

“I expect so,” said Ted, readily. “I always look after that side of the business.” + 

“Would you mind running across and getting me one of the envelopes that you use?” + 

“Of course.” Ted left the room, and returned within a couple of minutes, holding an envelope which he handed to Mr. Ludgrove. “Those are what we always use,” he said. “We’ve had them for nearly two years now.” + 

“Do you know where they came from?” asked Mr. Ludgrove, examining the envelope with great interest. + 

“Dad bought a large quantity of them, ten thousand, I believe, from a wholesale stationer somewhere in the Harrow Road,” replied Ted. “I forget the name of the people. They were going out of business, or something, and were selling the stuff off cheap. Dad had an idea of sending out a lot of circulars, and thought these would do to send them in. But the scheme fell through, and I’ve been using them for ordinary business purposes ever since.” + 

“I see,” said Mr. Ludgrove thoughtfully. “Now, it is a very extraordinary thing that the envelopes which have been shown me as having contained these numbered counters, are exactly the same in every respect as this that you have just given me.” + 

This remark was received in horrified silence. It was Ivy who broke it. “Mr. Ludgrove!” she exclaimed. “You don’t mean⁠—” + 

“I mean nothing,” replied Mr. Ludgrove swiftly. “I am trying to make you both see one aspect of this matter which has caused me much anxiety for some time. The counters were marked with a pen and ink exactly similar to those you have in your office, Ted. The envelopes in which they were sent are exactly the same as the ones you possess and have used for many years. The addresses were typed with a Planet machine, which, according to Miss Tovey, are not to be found in every office. Finally, the letters were posted in this district, W.2. You cannot fail to see the inference which must infallibly be drawn.” + 

“But, good heavens, the idea’s absurd!” broke in Ted. “You mean that the counters were sent out from our place!” He laughed mirthlessly, while Ivy stared at the grave face of the old herbalist, only half comprehending. + 

“You, Ted, have seen at least one of these counters,” continued Mr. Ludgrove, in a quiet and solemn voice. “Do you remember ever seeing anything like it before?” + 

Ted stared at Mr. Ludgrove, and the incredulous expression of his face turned slowly to one of mingled amazement and horror. “Why, yes,” he stammered. “Dad had a box of white bone counters just like the one I saw. He used to ask his friends in to play some card game, in which these counters were used. I haven’t seen them for a couple of years or more.” + 

Again there was a silence, broken by something that sounded like a sob from Ivy. Ted turned towards her with a despairing gesture. “It isn’t true!” he exclaimed. “I can’t explain it, but it isn’t true! Dad couldn’t have done it. Why should he? There’s some terrible mystery behind all this. I shall never believe that poor dad had anything to do with it. Why was he killed himself, if he had?” + 

He turned appealingly to Mr. Ludgrove. “You don’t believe it yourself, do you?” he said. + 

“Your father was my friend, and I should be the last to accuse him,” he replied. “But, in fairness to you both, I was bound to point out the direction in which any enquiry as to the counters must lead. I do not profess to understand it, but I must warn you that a man like Inspector Hanslet cannot fail to perceive the points I have mentioned.” + 

“But what am I to do if he questions me?” asked Ted distractedly. + 

“Tell the truth,” replied Mr. Ludgrove solemnly. “Hide nothing, for if it is discovered that you have concealed anything, it will tell all the more heavily against your father. There is only one true court of justice, the court of our own hearts. A consciousness of innocence is the only support against an unjust accusation. It would perhaps have been better had your father realized this.” + 

XVI + 

Corfe Castle + 

For a couple of days after Inspector Hanslet’s last visit to the house in Westbourne Terrace, Dr. Priestley’s attitude had sorely puzzled Harold. He had hardly spoken a word, and the greater part of his time had been spent in sorting out the mass of documents which had accumulated during the course of years in the massive presses which lined the walls of his study. Harold said nothing, knowing from past experience that it was useless to ask questions. When the Professor was ready to issue his instructions he would do so. Until then, untimely questions would merely be rewarded with a rebuff. + 

It was therefore with intense eagerness that Harold replied, one morning shortly after breakfast, the Thursday following the death of Mr. Copperdock, to an abrupt question by his employer: “My boy, what I am about to say to you must remain a secret between ourselves, until either my death occurs or I give you leave to speak. Is that understood?” + 

“I undertake not to breathe a word to anybody,” replied Harold. + 

“To nobody,” repeated the Professor emphatically. “Not even to Hanslet, however urgent the need may seem. I am going away for a time; how long that time may be I cannot tell. I do not wish my whereabouts to be known, as that would possibly place me in considerable danger.” + 

“You’re not surely going alone, sir!” exclaimed Harold. “You’ll let me come with you, especially as you say there is danger attached to your journey?” + 

But the Professor shook his head. “The danger may exist in London equally,” he replied. “It is essential that someone I can trust should remain here. Otherwise, my boy, I should be more than pleased to take you with me. Now, listen very carefully to these instructions. Do not leave the house for long at a time, especially in the evening. Open all my correspondence, and deal with it to the best of your ability. Should there be among it any letter of a startling character, put a message in the personal column of The Times, ‘The asp has struck,’ and sign it ‘Cleopatra.’ Do you follow this so far?” + 

“Yes, sir,” replied Harold simply, but gazing at his employer in bewilderment. There was something theatrical about these extraordinary precautions utterly foreign to the Professor’s usual methods of procedure. + 

“Very well,” continued the Professor. “If I find it necessary to communicate with you it will be by letter. The contents of the letter you may neglect. It may be typewritten, or in a disguised hand. You will know the letter is from me by the fact that it will be addressed in the first place to Westbourne Grove. The word Grove will be ruled through, and the correct word Terrace substituted for it. The envelope will in fact, convey the message. If the contents of the letter are to be read, which will only be if any unexpected developments take place, the envelope will be stamped with a three-halfpenny stamp. If, on the other hand, it is stamped with a penny and a halfpenny stamp, you will immediately proceed to the Post Office from which it was sent, which you will discover from the postmark, where you will wait till I join you. If the envelope is stamped with three separate halfpenny stamps, you will go to Inspector Hanslet, explain what I am now telling you, and persuade him to come with you at once to the place indicated by the postmark. Is that clear?” + 

“Perfectly clear, sir,” replied Harold. “I’ll just make a note of that code, if you don’t mind, sir.” + 

“No, make no notes!” commanded the Professor. “I have purposely contrived the code so simply that you can carry it in your head. You must realize that our actions will very probably be watched, in fact, I should not be surprised to learn that they have been under observation for some considerable time. Now, the next thing I want you to do is to type out a few copies of this paragraph and distribute them to the news agencies.” + 

He held out a scrap of paper as he spoke, and Harold took it from him. It ran as follows: “Dr. Priestley, whose scientific writings have rendered his name familiar to the British public, has received a cablegram begging him to deliver a series of lectures at a number of the Australian Universities. Dr. Priestley, who has just completed the manuscript of his forthcoming book, Some Aspects of Modern Thought, has accepted the invitation. Since he is anxious to return to England before the end of the year, he has left London hurriedly via Southampton and Havre, in order to catch the Celestial liner Oporto at Marseilles. He will travel by the Oporto to Sydney.” + 

In spite of several attempts upon Harold’s part, he could elicit no further information from the Professor. He typed out the paragraph, and took it round to the agencies himself. When he returned, he found the Professor upstairs busily engaged in piling a quantity of clothes, which he was never likely to wear, into three or four large trunks. + 

“You aren’t really going to Australia, are you, sir?” he ventured. + 

“It would be quite useless for me to announce the fact unless I were to make every appearance of so doing,” replied the Professor tartly. “The boat train for Havre leaves Waterloo at half-past nine, I understand. You will arrange for two taxis to be here at a quarter to nine. I always like to give myself plenty of time to catch the train.” + 

The Professor was normally one of those people who travel without any fuss. But on this occasion it seemed that he could not accept anything unless he had seen it done with his own eyes. He stood on the steps of the house for at least five minutes, directing the taxi-drivers where and how to distribute his trunks. When he and Harold arrived at Waterloo, he insisted upon interviewing innumerable officials, to each of whom he gave his name, asking endless and apparently irrelevant questions. Finally, having secured his seat, he walked up and down the platform several times the whole length of the train, instructing Harold as to the disposition of his household in his absence. It was not until the train was on the point of starting that he took his seat. + 

“Remember what I told you, my boy,” were his last words as the train moved off. + 

The Professor had booked to Paris, where he arrived before noon on Friday. He fussed about the Gare St. Lazare for some little time, and finally put his trunks in the cloakroom. He then went to one of the smaller hotels in the Quartier de l’Europe, booked a room, for which he paid in advance, and arranged for the collection of his trunks from the station. He lunched at a big restaurant in the boulevards, and spent the afternoon at the Louvre. In the evening he returned to the Gare St. Lazare, ten minutes before the Southampton boat train was due to leave. He booked a ticket for Southampton, and with a directness in singular contrast with the indecision he had displayed on the outward journey, took his seat in the train. He reached Southampton early on Saturday morning, and remained in his cabin until the London train had left the docks. Then, carrying a single suitcase, he walked to the West station and took a ticket to Corfe Castle. + 

Dr. Priestley, although he was known by name to a very large circle of newspaper readers, who were periodically entertained by one or other of his thrusts at some pet nostrum of the moment, such as the craze for brown bread or the discovery of vitamines, rarely or never appeared in public. He had even escaped the doubtful honour of having his photograph reproduced in the evening papers, though this perhaps was a disadvantage, since it would certainly have been unrecognizable. He was therefore in no sense a public figure, in that he was most unlikely to be distinguished from the ordinary crowd of travelling humanity. He sat in the train without any attempt at disguise, studying an ordnance map which he had laid open upon his knees. + 

It was still early when he reached Corfe Castle. The village, with its commanding ruin perched upon the summit of a conical hill, was in full flood of its morning activity. Dr. Priestley, standing at the station gate, watched the passersby for a moment with keen interest. Not one of them paid him the compliment of more than a fleeting and incurious glance. + 

He walked towards the heart of the village, and entered the first inn he came to. Having ascertained that he could have a single room for as long as he liked, he announced his determination of spending a few days, and was finally shown into a comfortable room with a view of the Castle. Here he remained until lunch. + 

The Professor lunched with keen enjoyment. His adventure was giving him an appetite. In spite of the amount of travelling which he had done during the last couple of days he felt thoroughly fit and well, much better than he had during the winter in town. The menace which had been revealed to him seemed far away to him in this peaceful spot, it almost seemed to him as though the whole of his discoveries had been merely some impossible dream, the penalty of overwork, and that the fresh country air, tinged with the faintly salt tang of the sea, had swept it from his brain into the realms of the unreal. Perhaps, after all, he was entirely wrong in his deductions. Those mysterious murders in Praed Street might have been the result of some entirely different influence. He had merely conjecture to guide him: somehow, now he had reached the place where alone the corroborative facts could be gathered, it seemed as though his actions and his fears were the effect of a sudden and unaccountable impulse. + 

He wandered from the luncheon room past the little saloon bar, and glanced in at the open door. The place was empty; it was past two o’clock, and the local habitués had returned to their labours. It was too early in the year for visitors. The Professor walked into the bar, and took a seat by the side of the counter. + 

The proprietor, who was serving a few belated customers in the taproom, came in at the sound of the Professor’s entrance, and greeted him with professional courtesy. + 

“Good afternoon, Mr. Deacon,” he said cheerfully. (Deacon was the name which the Professor had inscribed in the hotel register⁠—it said much for the proprietor’s skill that he had deciphered it correctly.) “I hope you found your room to your liking, and enjoyed your lunch?” + 

“Yes, thank you,” replied the Professor. “I think I shall be very comfortable here for a day or two. I looked in here to ask you for a liqueur after my lunch. Perhaps you will join me in one?” + 

“Liqueurs ain’t much in my line, thankee, sir,” replied the landlord. “But I’ll take a drop o’ gin with you, since you’re so kind. What’ll be yours, sir? I’ve got Benedictine, Crème de Menthe⁠—” + 

“I should prefer some old brandy, if you have it,” interrupted the Professor. + 

“Ah, you know a thing or two, Mr. Deacon, I can see that,” replied the landlord with a knowing wink. “I’ve got a rare drop of brandy put away in the cellar. I never had only six bottles of it, and there’s still four left. My customers don’t hardly ever ask for it, it’s mostly beer or whiskey with them. Unless it happens to be a gentleman from London like yourself, sir.” + 

He disappeared, and returned in a few moments with a long-necked bottle, from which he poured a glass of pale amber liquid. “There, just try that, sir,” he exclaimed proudly. + 

The Professor picked up the glass and sampled the contents gravely. “Excellent, very excellent indeed!” he commented approvingly. “I am quite sure that my doctor would have prescribed this as part of the cure, had he known of it.” + 

“Cure, sir?” enquired the landlord sympathetically. “I hope the illness has not been serious?” + 

“Oh, no, not at all,” replied the Professor. “One could scarcely call it an illness. I have been rather run down, that is all. Men of my age have to take care of themselves, you know, and I have been devoting rather more time and energy than was perhaps wise to my business in the City. I found myself suffering from headaches and loss of appetite, so my doctor ordered me a complete rest. He said it was the only thing to set me up again.” + 

“Well, here’s your very good health, sir,” said the landlord, tossing off his gin. “You couldn’t have come to a better place than this for a rest. I was afraid, when you comes in, that you’d find it too quiet at this time of year. I says to myself, ‘Here’s a gentleman from London who’ll be looking for a band and a promenade and whatnot?’ Why, sir, there isn’t even a sharry running at this season.” + 

“That fact adds another attraction to your most comfortable house,” replied the Professor. “It was my doctor who recommended me to come here. He motored through on his way to Swanage last year. He recommends me to take a fairly long walk after every meal. I understand that you have some very beautiful heaths around here?” + 

“They may be beautiful, but they’re precious lonely,” said the landlord. “They may suit you all right, sir, but for my part I take the bus into Wareham or Swanage when I wants to get out for a bit.” + 

“I shall not be sorry to enjoy the loneliness of the countryside, after the bustle of London,” replied the Professor. “But I suppose people do live on these heaths, do they not?” + 

“Well, there’s a few clay pits, and now and then a gravel quarry,” said the landlord. “But, take it all round, you can walk a long way without meeting a living soul, so long as you keep off the main road. It is like that all over Purbeck, whichever way you go. Of course, there’s a few cottages where the clay-workers live, but that is about all, outside the villages, and there ain’t many of them.” + 

“What an ideal spot on which to build a country retreat!” exclaimed the Professor. “Not one of those villa residences, which are growing up so plentifully all over the country, but just a cottage, in the true sense of the word, where one could enjoy without distraction the glories of nature!” + 

The landlord looked at the Professor with a curious expression. “You wasn’t thinking of doing anything like that, was you, sir?” he enquired. + 

“Why, no, not at present, however much the idea might appeal to me,” replied the Professor, artlessly. “I fear that my duties in London would not allow me sufficient leisure.” + 

“Queer thing, now, that you should say that about a cottage, sir,” said the landlord confidentially. “It puts me in mind of an odd thing that happened in these parts, not so many years ago. All along of another gentleman, about the same age as you might be, sir, coming into this very bar and asking me if I knew of a lonely cottage for sale.” + 

“Indeed?” replied the Professor casually. “Perhaps you would refill my glass with that most excellent brandy. And if you will do me the honour of taking another glass of gin with me⁠—” + 

“You’re very kind, sir,” said the landlord, filling up the glasses. “I thought you’d take to that brandy. As soon as I sees you taste it, I says to myself, ‘Here’s a gentleman that knows a good drop of liquor when he sees it.’ ’Tisn’t every gentleman that takes kindly to the drink nowadays, sir. Why, there’s some of them what drops in here for lunch as takes water with it! Can’t say I hold with it myself. Well, here’s your very good health, sir!” + 

He consumed his glass of gin at a gulp, and stood with his elbows on the counter, looking at the Professor. “Your saying that about the cottage does put me in mind of that other,” he said, reminiscently. “Mind you, sir, not that he was like you at all. Of course I didn’t know who he was when he came in, but I say to myself, ‘That fellow’s no business man, I’ll warrant!’ And, as it turned out, I was right! But you can always tell, can’t you, sir?” + 

“Usually,” agreed the Professor. “He was not a business man then?” + 

“Not he!” exclaimed the landlord, contemptuously. “He was one of them scientific chaps, like you reads about in the papers. What good they does I don’t know! Always seems to me as though they’d be better employed doing something useful instead of talking a lot of gibberish decent folks don’t understand. Well, this poor chap suffered for his folly, anyhow.” + 

“Why, what happened to him?” enquired the Professor without any great show of interest. + 

“Burnt to death!” replied the landlord, impressively. “Burnt till there wasn’t nothing but a heap of charred bones left, sir. Terrible thing it was, and him all alone out on the heath there. Quiet enough chap he seemed too. Why, I couldn’t believe my ears when the constable told me about him afterwards. You wouldn’t have guessed what the chap was really, not if you was to try for a twelvemonth.” + 

“I daresay not,” remarked the Professor dryly. “I never was good at guessing. What was he?” + 

“Ticket o’ leave man!” exclaimed the landlord, leaning over the counter confidentially. “If you’ll believe me, that man had just served fourteen years hard on Dartmoor for murdering a Duke, when he walked into my bar as cool as a cucumber. Oh, he was a deep one, was that Mr. Morlandson! And not a soul bar the super knew a word about it!” + 

“Burnt to death, was he!” remarked the Professor. “Dear me, what a terrible end. How did it happen?” + 

“No one knows rightly,” replied the landlord. “He lived all alone on the heath, over yonder towards Goathorn. Built himself a concrete place, I can’t remember what the super said he called it. Word something like lavatory?” + 

“Laboratory, perhaps?” suggested the Professor. + 

“Aye, that’s it, sir. You can see the ruins of it still, they tell me. I haven’t been out that way since it happened. Used to lock himself up in this place of his, and fiddle about with all sorts of inflammable stuff. Bound to go up it was, and sure enough it did. Just after closing time one evening, Old George what lives way out towards Studland, comes knocking at my door and says the heath’s on fire. ‘Heath on fire!’ I say, ‘Why, it’s been raining for a week. What are you talking about?’ ‘ ’Tis that for sure!’ says old George. ‘You can see the flames up along my way.’ ‘Flames!’ I says, ‘It’s the stuff they gives you at the Red Bull over yonder that makes you see flames, and I don’t wonder at it!’ Well, he keeps on, and at last I goes half a mile or so up the road with him. Sure enough, there was a great pillar of flame coming up from the middle of the heath. + 

“We hadn’t been there more than a minute when the constable comes along. ‘What’s up yonder?’ I says. ‘Morlandson’s place on fire,’ says he. ‘Super he’s gone off on his bike. You chaps best come along and see what you can do.’ + 

“Well, sir, it weren’t no manner of good to take the engine. She’s only one of them hand concerns, and last time we’d had her out to practice, she pumped back’ards like into the river instead of out of it. Joe Stiggs, him what looks after her, said he found he’d put the valves in the wrong way. Besides, it would have taken us best part of an hour to push her out there, there ain’t no regular road. And, what’s more, all the water out at Morlandson’s place was a well what ran dry every summer.” + 

“Then there was nothing to be done?” commented the Professor. + 

“Nothing whatsoever,” replied the landlord emphatically. “Mind, we didn’t know Morlandson was inside. We expected to find him running round outside chucking water at it from a bucket. However, off we goes, and as we gets close we catches the stink of it. Lord! I shan’t forget it in a hurry. It was like the smell what comes from the pits when they burns carcases when the foot-and-mouth’s about. + 

“The super he meets us, and I reckon I hollered out when I saw him by the light of the fire. He was black as a sweep, and all the hair singed off his face. Told us he’d been into the cottage, which was burning like a dry rick, and that he couldn’t find Morlandson anywhere. ‘I reckon he’s in there,’ he says, pointing to the lav⁠—labor⁠—what you call it. ‘There’s a horrible smell of burnt flesh about.’ + 

“He was right there, it fair made me sick. But there was nothing to be done. You couldn’t get within fifty yards of the place. We waited till nigh on midnight, but even when the flames went down the walls was red-hot and we weren’t no further for’ard. Super, he stays on all night, and in the morning he finds what’s left of Morlandson, and that’s precious little.” + 

“Dear me, what a terrible thing!” exclaimed the Professor. + 

“Aye, that it was,” agreed the landlord. “They brought back what there was of the poor chap in a potato sack, held an inquest on him, and buried him in the churchyard yonder. And that is what happened to the last gent what fancied a lonely life on the heath, sir.” + 

The landlord glanced up at the clock, the hands of which pointed to five and twenty minutes to three. “Hallo, I must close the bar, or I’ll be getting into trouble,” he said, reluctantly removing his arms from the counter. + 

“A visit to the scene of the tragedy would provide me with an object for a walk,” said the Professor. “Which is my best way to it?” + 

“You can’t go wrong, provided you don’t mind a bit of rough going,” replied the landlord. “If you go out of the village towards Wareham, you’ll come upon a railway track, what they runs the trucks of stones along. That goes to Goathorn pier, a matter of six mile away or more. Follow the line for nigh on three mile, and you’ll come to a clay-pit. Then, about a quarter or half a mile away, on your right, you’ll see what’s left of the place, standing up among the gorse and heather. There is a track, but it’s a long way round and plaguey hard to find if you don’t know it. Now, if you’ll excuse me, sir, it’s past closing time.” + 

XVII + 

The Clay-Pit + 

Dr. Priestley walked out of the inn, and down through the village towards the ruined castle, standing upon its curiously artificial-looking mound. He had attained one of the objects of his visit, corroboration of the story of the death of Dr. Morlandson, and that without asking questions which might have suggested that he had any interest in the matter. Since the landlord had himself volunteered the information, there could be no reason for his having distorted the truth. Morlandson, by the evidence of those best qualified to speak, was dead, and his charred bones were resting in the quiet churchyard which the Professor was at that very moment passing. + 

He felt a great desire to see the site of the tragedy, but his natural caution prevented him from walking to it immediately. He was most anxious to avoid any suspicion that Mr. Deacon, the City merchant, was in any way interested in the fate of the ex-convict. But, on the other hand, there was no reason why he should not visit the ruins of the castle, the scene of the murder of King Edward the Martyr, three-quarters of a century before the Conquest. It was the show place of the district, the natural magnet for any casual visitor like himself. + 

The Professor climbed slowly up the steep slopes of the natural earthwork, which stands like a fortress guarding the only gap in the long range of the Purbeck hills, and listened attentively while the guide, delighted at finding a sympathetic audience so early in the year, recounted the history of the stronghold and indicated its more prominent features. Then, his inspection over, he sat down on the grass on the northeastern slope of the hill, and drew his ordnance map from his pocket. + 

His horizon was bounded by the high land on the southern side of the River Stour. At his feet was a rolling, sandy plain, diversified here and there by clumps of trees, but mostly covered with gorse and heather. This plain stretched away into the distance, and beyond it an occasional silvery gleam betrayed the winding channels of Poole harbour. Here and there across the plain he could see evidences of human occupation, the white surface of a clay-pit or the roof of a tiny isolated cottage. But, apart from these, the tract of country over which he looked appeared utterly deserted, abandoned to a great silence disturbed only by the note of some hovering bird. + 

His map told him that no road traversed this expanse. Only a few winding paths, trodden by the feet of rare wayfarers, led away from where he stood in the direction of the thin whisps of smoke which indicated human habitation. Here and there he could see traces of the railway of which the landlord had spoken, which led from the hidden quarries behind him to a pier built upon one of the secluded arms of the harbour. It seemed to be but little used. The Professor, enjoying the quiet of the fine afternoon, sat for hour after hour, his eyes absorbing the subtle beauty of this unharassed land. And, except for the solitary figure of a labourer, tramping stolidly across the waste towards some unknown destination, he saw no sign of life in all the wide extent of country laid out before his eyes. Yet, somewhere, lost among the lonely solitudes of gorse and heather, lay the solution of the mystery which he had set himself to solve. + 

Dr. Priestley smiled as the conviction that this was so came back to him with redoubled force. Utterly contrary to his usual methods of procedure, he had formed a theory based entirely upon conjecture. So far, these facts by which it must be tested seemed to point to the incorrectness of this theory. Yet, were they facts? Was it not even yet possible that some master brain had arranged these seeming facts in order purposely to mislead an investigator like himself? And, if so, what unknown dangers might he not be incurring by the attempt to prove them false? + 

The Professor had never shirked danger throughout the whole course of his career. And in this case, as he reflected, he already stood in such imminent danger that his present actions could hardly increase it. If his theory were correct, a determined and unknown assassin held in his hand already the weapon which was aimed against his life. Why had he not struck, months ago, when the Professor was in blissful ignorance that his life was threatened? This was one of the aspects of a case which, in spite of the perils which it held for himself, thrilled him as no case had ever thrilled him before. + 

Sitting here, contemplating the peaceful afternoon, the Professor reviewed his theory for the last time, testing it with all the apparatus of probability. It must be correct, there was no other theory which would fit in with all the data before him. Yet, how could it be correct, in the face of the formidable array of facts which seemed to disprove it? This seeming contradiction it must be his task to unravel, and that alone. + 

For he had realized at once that it was no good calling in the aid of the police, even of Hanslet, whose experience had taught him that the Professor’s most extraordinary statements had a way of justifying themselves. The police would merely confront him with their so-called facts, and seek to prove to him that his theory was utterly untenable. He could give them nothing tangible to go upon, could give them no clue which would lead to the capture of the undetected criminal he knew to be at large. Even if they accepted his theory in its entirety, how could they protect him from the dangers which encompassed him? Sooner or later, in some unguarded moment, the shadow would leap out upon him, and the Professor’s theory would be proved upon his own body. + 

No, physical precautions were useless. It must be a battle of wits between them⁠—himself and this mysterious killer. How far had a watch been kept upon his own actions, the Professor wondered? He was almost certain that he had not been followed to Corfe Castle, but he was by no means so certain that his pretended departure from England had imposed upon his adversary. The Times of Friday had contained the paragraph mentioning his visit to Australia. So far, so good. But it was almost with surprise that he had failed to find the message in the personal column, which should inform him that the letter which he daily expected had arrived. + 

The Professor rose to his feet, and walked slowly back to the inn. He had ordered dinner at seven o’clock, and it was already past six. The landlord was standing at the door, and the Professor nodded pleasantly to him as he entered. + 

“What a beautiful afternoon!” he said. “I have been admiring the view from the Castle. A very fine prospect indeed, is it not?” + 

“Well, sir, some admires it and some don’t,” replied the landlord. “I fancies something with a bit more life in it myself. But I dessay it’s a change to you after London.” + 

“It is, indeed,” agreed the Professor. “Indeed, I am so taken with the look of the heath, that I propose to take a walk across it after dinner.” + 

“Well, don’t lose your way, sir. It’s a bit lonely out there. You aren’t likely to meet anyone who’ll put you right, either.” + 

“Oh, it is not really dark till ten o’clock,” replied the Professor cheerfully. “I have my map, and the Castle ruins must be visible from a long way off. You need have no fears of my getting lost.” + 

“There’s no danger, sir,” the landlord hastened to agree. “Only you might happen to wander a bit further afield than you meant to. The bar closes at ten, but if you happen to be later than that, you’ve only got to knock on the door. I shan’t be abed afore eleven.” + 

The Professor’s dinner was served punctually at seven, and by eight o’clock he was well on the road of which the landlord had told him, and which his map showed him led in the direction of the railway. A short distance beyond the village he found a narrow lane, which, after a few twists and turnings, brought him out upon the track. There was a narrow path beside it, and along this he stepped out, anxious to reach his destination while it was still broad daylight. + 

The track followed a devious path across the heath, which, viewed from near at hand, was more undulating than at first appeared. The track had been built to avoid the steeper gradients, but every now and then it ran upon a low embankment or through a shallow cutting. On either side the heath spread out, silent and mysterious, sometimes bare and sandy, with twisted pine trees standing above it at intervals, sometimes covered with low, dense thickets, in which the general silence seemed to be accentuated. When the line rose slightly to cross one of the lesser eminences, the Professor caught a fleeting glimpse of still water, the wandering arm of some unfrequented lagoon among the islands of the harbour. Behind him the sun hung low over the long range of the Purbeck hills, which changed from green and gold to blue and purple as the sun sank ever lower. Against them, the sharp outlines of the ruined Castle stood out clear cut like a beacon. + 

As the Professor strode on through the silence, devoid of any vestige of human habitation, he noticed how admirably adapted was this barren heath to purposes of concealment. Spread over its surface were a series of shallow depressions, shaped like a saucer, and sometimes holding an abandoned gravel pit, now half filled with stagnant water after the winter rains. A man might lie concealed in one of these, secure from observation, for as long as he could keep himself supplied with food. There would be no risk of discovery, those whose business led them to cross the heath kept strictly to the narrow paths, barely a foot wide, which meandered at wide intervals through the close growth of heather. A living man, so long as he avoided observation from these paths, might lie hidden for as long as he chose. And if a living man, why not a dead body? How easy to drag the damning evidence of crime into one of those dark thickets, to sink it into the silent depths of one of those black, unruffled pools! + 

The Professor shuddered, and increased his pace. This lonely heath was no place in which to indulge in morbid thoughts. His life might be in danger, but somehow he felt that it was not here that the blow would fall. If his theory were correct, if he had gauged aright the psychology of his adversary, it would not be thus that he would meet his death, here where there was none to witness the blow. Despite the almost threatening aspect of the country, deepening in tone every instant as the sun sank lower behind the distant hills, there was no vestige of any real danger. The shadows that lurked amid the gorse and heather were but the shadows of his own fears. + 

So the Professor reasoned with himself. It would have been folly for him, wishing as he did to avoid any suspicion of his interest in Dr. Morlandson, to approach the scene of his death during the day. The very track by the side of which he was walking contained a potential risk of discovery. It must be used sometimes, the rails showed signs that wagons had passed over them not so very long ago. They led only to a pier, or rather jetty, upon which the contents of the wagons were unloaded into a waiting barge. The pier was utterly unfrequented except by these barges. The track, in fact, was a dead end as far as any casual wayfarer was concerned. There could be no rational excuse for following it. + 

He topped a slight rise, and saw in the distance the white surface of the clay-pit which was to be his guide. From where he stood, he could see a considerable distance on either side of him. There was no sign of life upon the heath, except that far away, perhaps a couple of miles, the outlines of a cottage stood out against the grey background. + 

The Professor reached the clay-pit, and searched the undulating surface of the heath for some sign of the remains of Dr. Morlandson’s laboratory. For some moments he failed to find it, and then, at last, he made out the jagged tooth of a broken wall thrust upwards from behind a clump of gorse bushes. This, no doubt, must be his goal. There was no path leading to it from the track, but the Professor, using his stick to feel the way, stepped out boldly across the heather, which yielded like a cushion to his footsteps. + 

The distance from the track to the ruin must have been six or seven hundred yards. It took the Professor some little time to cover it, since he was obliged to make several detours in order to avoid clumps of gorse. But he reached it at last, and stood on the edge of what had once been a clearing, surveying the scene that lay before him. + 

The cottage itself had completely vanished. All that remained of it was a mound thickly overgrown with weeds and coarse grass, from which protruded here and there fragments of charred beams and rafters. The encroaching heath had hidden any signs of any garden there might once have been, and it was impossible for the Professor to form any idea of what the place had looked like while it was still standing. But the laboratory, having been built of concrete, had defied the utter obliteration to which the rest of the premises had succumbed. Its broken walls, rough and jagged, stood up in a gaunt rectangle, roofless, their foundations hidden deep in the all-effacing vegetation, but still marking without fear of error the site upon which the building had stood. + 

The Professor pushed through the weeds and undergrowth until he reached the gap in the wall where the door had been. The door was still there, rusty and twisted, lying almost hidden at the base of the wall, where it had been thrown by Dr. Morlandson’s would-be rescuers. It was a plain sheet of iron, fitted with hinges and a lock. The Professor glanced at it, then passed through the doorway into the space enclosed between the walls. Something, perhaps a grass-snake, rustled among the grasses as he entered. + 

The laboratory had been a fairly spacious room, about thirty feet by fifteen. Of its interior fittings nothing whatever remained. As the Professor advanced into the interior of the space his boots struck metal at every other step. He stooped and probed with his stick, and brought to light a twisted and shapeless tangle of iron, which might once have been the frame of a skylight. He examined it for a moment, and then cast it aside, with a nod of comprehension. The walls themselves still showed upon their interior surface the signs of having been subjected to an enormous heat. He poked about inside the laboratory for a short while longer, then came out and sat down upon the mound which had once been a cottage. + 

There could be no doubt that the fire which had destroyed the laboratory had been far fiercer than that which had burnt down the cottage. The charred beams of the latter still existed, while nothing whatever remained of the wooden fittings of the former. And yet, in case of a concrete-built laboratory, one would have expected a fire merely to have burnt out the interior without doing much damage to the structure. The place must certainly have contained a large quantity of substances whose combustion produced great heat, such as thermite. And Dr. Priestley knew enough of the methods of research chemists, who as a rule deal in very small quantities, to wonder why Dr. Morlandson required such large quantities, and why, even supposing that his isolated situation made it necessary for him to obtain his supplies in bulk, he should store them in the laboratory itself. The suspicion that Dr. Morlandson’s activities had not been solely concerned with researches into the properties of medicinal drugs seemed to the Professor to be thoroughly well grounded. + 

To the Professor’s mind, there was even something suspicious about the origin of the fire itself. Dr. Morlandson had been aware of the danger of such an outbreak; he had warned the police superintendent against smoking in the laboratory. This being so, was it likely that he would lock himself into what had proved to be a regular deathtrap, and leave himself with no means of escape? The doubt raised by these queries set the Professor’s mind to work upon an entirely fresh train of thought. Had Dr. Morlandson’s death been as accidental as it had appeared? Or was it possible that he too had had an enemy, who had somehow contrived the whole affair? And, if so, what became of the theory which had brought the Professor to the Isle of Purbeck? + 

The Professor awoke with a start from his meditations, suddenly conscious that the light was failing rapidly. It was already past sunset, the ruined Castle which was to be his landmark was now indistinguishable against the universal grey of its background. A faint, silvery mist was rising above the heath, wreathing every object within sight with a curious opalescent halo. The Professor realized that he had already spent long enough contemplating this deserted heap of ashes. Their secret, did they hold one, was not to be wrested from them by further study that night. + 

He turned his back upon the gaunt skeleton of the laboratory, and walked round to the further side of the mound. Here the stumps of a rotten post or two showed where a fence had probably surrounded the front garden, now long since overgrown. Beyond the posts a white thread caught the Professor’s eye, and he made his way up to it. It was a narrow track, apparently disused for years, and had no doubt once been the path by which the cottage was approached. + 

In one direction it led towards the railway line by which the Professor had approached the place, and rejoined the line lower down than the point at which he had left it. He started to walk down the track, with a muttered exclamation of satisfaction. By following it he might add a yard or two to his journey, but it would save him a slow and tiresome trudge through the heather in the gathering darkness. Of his ability to find his way back to the inn he had no doubt. He had only to follow the railway line backwards until the lights of the village came in sight, and then strike across country till he reached them, even if he missed the lane by which he had come. + 

The Professor had not gone very far before he stopped dead, and bent down to examine the narrow white strip beneath his feet. He felt in his pocket, and struck a match, which he held close to the surface of the path. It was a still, windless evening, and the flame of the match burnt clear and unflickering, illuminating a narrow circle of fine, white sand. Across the centre of this patch, following the path upon which the Professor stood, ran the sharp and unmistakable imprint of a bicycle tyre. + 

Somehow the discovery made the Professor’s pulses beat quicker than before. This apparently deserted track was in use, then, despite its overgrown appearance. No doubt it formed a shortcut between two spots upon the heath, such as a pit and a clay-worker’s cottage. This was the obvious explanation, but to the Professor’s mind it seemed unsatisfactory. He had studied the map very carefully that afternoon, and knew roughly the location of every human habitation marked upon it. And this particular track seemed to run in the wrong direction to connect up with any of these. Was it possible that somebody beside himself was interested in the ruined cottage which he had just left? + 

He threw the match away, and strode forward briskly in the direction of the railway line, which he calculated must now be less than a quarter of a mile ahead. He had an uncanny feeling that the rider of the bicycle might have been concealed close at hand while he was investigating the ruins, that he himself might have been the object of close observation all the time he had believed himself to be alone in the vast emptiness of the heath. It was an uncomfortable and a disturbing thought, and the Professor pushed on rapidly, grasping his stick tightly. Of course it was absurd, he was not the least likely to be molested. But he could not keep his mind from drawing ugly pictures of the dark thickets, of those deep, black pools, so admirably adapted as a hiding place for a murdered body⁠— + 

And then, all of a sudden, with an abruptness which fell upon his ears like a blow, the Professor heard a bell ring sharply behind him. He spun round in his tracks, raising his stick instinctively, as though in self-defence. Coming along the path behind him was a tall figure on a bicycle, indistinguishable but for its outline in the swiftly-falling night. The slight mist magnified it to inhuman proportions. + 

Dr. Priestley stepped back into the heather, and waited for the figure to approach him. As it came nearer he began to distinguish details one by one. It was a man, dressed apparently in trousers and jersey, with a seaman’s cap upon his head. The Professor felt a sudden feeling of relief. No doubt this was a man from one of the stone barges which came up to Goathorn Pier to load stone or clay. He would no doubt join the railway, and follow the track beside it down to the pier. He could see the man’s features by now, or such of them as were not hidden by the mass of black beard, which grew up in whiskers on either side of his face until it was lost beneath his cap. And then, with a sudden recollection of a certain vivid description which Hanslet had given him, the Professor realized that the man had an angry-looking scar extending the whole length of his right cheek. Even as he realized the significance of the man’s appearance, he had dismounted from his bicycle, and stood confronting the Professor. + 

“Good evening, Dr. Priestley,” he said pleasantly, but in a curiously harsh and strained voice. And, at the words, the Professor knew that this was indeed the Black Sailor. + 

XVIII + 

The Avenger + 

The Black Sailor stood in the middle of the path, leaning on his bicycle and looking at Dr. Priestley with a faint smile of amusement in his eyes. The Professor, for his part, stood his ground and waited for what might come next. He understood quite well that any attempt to escape would be pure folly. If it came to a chase across the heather, the sailor would overtake him in half a dozen strides. And as for shouting for help⁠—well, the nearest inhabited house was nearly two miles away. + 

Besides, what was there to shout about, after all? The sailor appeared to be unarmed, and his expression was rather one of amusement than of menace. The absurdity of the situation began to appeal to the Professor. He had been accosted by the man whom the police would have dearly loved to lay their hands upon, and he was utterly powerless to take any steps towards his capture. + 

The Black Sailor broke the silence. “You seem interested in the fate of the unhappy man who ended his days in this lonely spot?” he said, with something that sounded like a short laugh. + 

“The fate of Dr. Morlandson has a particular interest for me,” replied the Professor significantly. + 

“Yes, it would have, naturally,” said the sailor conversationally. “It has puzzled me why you have been so long in realizing it. I didn’t expect it of the others, but you, surely, should have guessed the motive long ago. It would interest me to know what brought the connection to your mind?” + 

The Professor hesitated. Yet, after all, he was in this man’s power. So far as he could see, his only chance of escape lay in gaining time, until by some miracle a belated labourer should come past within hailing distance. It was the most unlikely thing in the world to happen, but there was just a chance. Consequently, since the sailor seemed disposed to talk, it was best to humour him. + 

“I guessed it first when I heard the name Copperdock again,” he replied. “I could not remember at first where I had heard it before, but finally, the whole scene came back to me.” + 

“Yes, it is an unusual name,” agreed the sailor, “but, if you will excuse my saying so, Dr. Priestley, you appear to be not entirely at your ease. Perhaps it will reassure you if I remind you that no single one of the victims of Dr. Morlandson’s vengeance has come to any harm until he has received the counter with his number on it. Although, as you seem to believe, you are included among them, you are perfectly safe until that token is delivered.” + 

“I have no alternative but to believe it,” replied Dr. Priestley, steadily, “for I was the foreman of the jury which condemned him.” + 

“It is for that reason that you have been reserved till the last,” said the sailor solemnly. “It was Dr. Morlandson’s wish that it should be so, and that, before you died, you should understand the reason for your punishment. Do you remember Dr. Morlandson, as you last knew him?” + 

“I remember him in the dock,” replied the Professor. “A tall, slim, clean-shaven man, with an intellectual face, and a pleasant soft voice.” + 

“You remember his appearance,” exclaimed the sailor impatiently, “you never knew the man’s soul, as I did. Dr. Morlandson loved two things in this world with a passion which filled his whole being, his wife and his profession. His sympathy with suffering was unlimited, and his nature recoiled from the spectacle of any pain which could be prevented. And you, twelve good men and true, took it upon yourselves to condemn him to death because he had the courage to put one of God’s creatures out of his agony. At one blow you took from him all that he loved and lived for, his profession, and his wife who died under the shock of her husband’s conviction. Can you wonder that during those long years of torment in prison, his thoughts turned from sympathy to vengeance? Yet, even in his vengeance he was merciful and killed swiftly.” + 

Dr. Priestley nodded. “Yes, I guessed that was the motive,” he said in a matter of fact tone. “I took the trouble to look up the names of the jurymen, as soon as I remembered that it was while I was serving on that jury that I had met a man bearing the name of Copperdock. The others were Tovey, Colburn, Pargent, Martin, Goodwin, Thomas, Bailey, Underhill, Abbott and Hewlett.” + 

“Quite right, Thomas, Bailey, Underhill, Abbott and Hewlett were already dead when Dr. Morlandson was released. Their punishment has passed into other hands. Of the remaining seven, six have paid the penalty which they wished to inflict upon Dr. Morlandson. You only are left, Dr. Priestley.” + 

“I had realized that my life was threatened,” replied the Professor calmly. “As you have probably guessed, it was for the purpose of verifying the fact of Dr. Morlandson’s death that I came here.” + 

“Dr. Morlandson is dead, but he left his vengeance behind him,” said the sailor sombrely. “You killed him as surely as though the law had taken its course upon your cruel verdict. He came here, a broken man, to die in solitude like a stricken animal. I met him, not a hundred yards from this very spot, a few days after he had come to live in the cottage. I was desperate that evening. I had murder in my soul, no matter why. I would have killed him then and there for what he might have had about him, but I was afraid. There was something about him that prevented me from touching him, I did not know what it was. He took me to the cottage with him, and talked to me all night. And at last I found out that he was in the grip of a hate greater than mine. + 

“I saw him every day after that. I was the only person he spoke to, except that fool of a police superintendent who used to come out to see him. He’d have been glad enough to lay his hands on me, if he had known that I was hiding within a few yards of him. Hour after hour we talked, Dr. Morlandson and I, while he fed me and sheltered me. He told me his whole story, and at last, when he knew he could trust me, he made me an offer. If I would become the heir to his vengeance, I should also be heir to a very large sum of money he had safely concealed. + 

“He explained his plans to me in detail. During his years in prison he had thought over every little thing, and his scheme was complete. But one thing he had not allowed for, and that was the fact that prison life had broken him up. He, who had gone to prison a strong man, came out ruined in health and body. His mind had eaten him up, as he put it. The awful hours of solitude, when his only means of diverting his thoughts from his wrecked life was to perfect his plans for vengeance, had sapped his youth and his strength. He came out an old man, utterly incapable of the task before him. + 

“I had told him my story, such as it was, and he saw in me the one man who could take his place. I was an educated man once, Dr. Priestley, forced by circumstances to abandon my former life and become what you see me now. In those months I was in Morlandson’s company he taught me more than I had ever learnt before. He told me the names of the men who had formed the jury, and showed me how I was to trace each of them. He had thought out dozens of ways of killing them undetected, and he explained to me how each should be employed according to circumstances. In that laboratory which he built he spent long hours working at poisons which should be swift and effective, in preparing weapons which could not fail in the clumsiest hands. He taught me anatomy, where the vital organs of the body lay, how to strike so as to produce instant death. Within a few months I was fitted to undertake the task which he had delegated to me.” + 

The Black Sailor paused, and looked intently at the Professor, as though to assure himself that he was taking in all that was being said to him. “It was Dr. Morlandson’s wish that you should fully understand the reasons for your punishment before you died,” he continued. “You, at least, we had no difficulty in tracing. Your name was frequently in the papers, you were the only one of the twelve who had attained any fame whatever, except perhaps that conceited ass Pargent. It was only fitting that you, as foreman, should be reserved until the last. Morlandson hoped that you would guess the reason for the deaths of your fellow members, and so realize the fate which was hanging over your head.” + 

“Yes, I think I understand it all pretty thoroughly now,” replied the Professor. “There are, however, one or two points upon which I am not quite clear. I am told that Mr. Ludgrove, the herbalist, has received a counter bearing the number VII. I presume that this is not due to you, since Mr. Ludgrove was not a member of the jury, nor, to the best of my recollection, was he concerned with Dr. Morlandson’s trial.” + 

The Black Sailor scowled, and looked fiercely at the Professor. “Ludgrove is an interfering busybody,” he growled. “I do not propose to explain my methods to you, naturally, but this much I will tell you, Ludgrove has on more than one occasion prevented me from carrying out my designs, I have no other quarrel with him, and he is in no danger so long as he minds his own business. The counter was sent to him as a hint to keep out of the business altogether. And, by the way, Dr. Priestley, when you get back to London, you may give him this message from me. Unless he keeps clear, the counter, which was only a warning, will be followed by something worse.” + 

He laughed harshly as he saw a flicker of astonishment pass across the Professor’s face. “Oh yes,” he continued. “You will no doubt go back to London and recount your experiences to your friend Hanslet and the rest of the police. Why not? I have no doubt they will be very pleased to learn the motive for these mysterious murders which have so sorely puzzled them. They may dimly realize that an apparent murder may sometimes be a just execution. But the knowledge won’t help them much, and it won’t help you, Dr. Priestley. In fact, it was Dr. Morlandson’s wish that the reasons for the deaths of his victims should be fully known. His example may cause jurymen to consider their verdicts more carefully in future. And as for me, what harm can any of you do? Why, from the first there has been a reward upon my head, a reward you will never earn, Dr. Priestley.” + 

He paused, and then continued more seriously. “You are a sensible man, and must see how utterly useless any attempt to put the police on my trail must be. It will take you an hour at least to reach the police station at Corfe Castle, and heaven knows how much longer to persuade the police to search for me. Don’t for an instant think this meeting is accidental. It is not. I have for some time been seeking for an opportunity of meeting you. It was Dr. Morlandson’s expressed wish that I should see you and explain matters. Now that I have done so, the Black Sailor will disappear, only to appear once more, when your sentence is to be executed.” + 

“And that sentence is⁠—?” enquired Dr. Priestley firmly. + 

“That you should live in the constant expectation of a violent death,” replied the Black Sailor gravely. “The time may come soon or late, but you cannot escape the doom which hangs over you. You may take what precautions you please, you may condemn yourself to a life of constant supervision within the walls of a fortified house. If you do, you will know something of the hell which Dr. Morlandson endured as the result of your verdict. But at last the moment will come, and you will be stricken with death when you believe yourself to be safest. Copperdock was warned, he was under the special care of the police, he was alone in his own house with the door locked behind him. Yet death found him, as it will find you when the time comes, Dr. Priestley.” + 

The Black Sailor put his foot on the pedal of his bicycle. “You will excuse me if I break off this interesting conversation,” he said. “I have many things to attend to tonight, and it is getting late. But before I go I will give you this. It will serve to remind you that your meeting with me was not a trick of your imagination. It may also be useful as evidence of your veracity when you tell the story to the police.” + 

He drew something from his pocket, and threw it contemptuously at the Professor’s feet. Then, before the latter could reply, he had jumped on his bicycle and was pedaling rapidly in the direction from which he had come. + 

It was quite dark by now, and the Professor watched his retreating form until it was lost in the night. Then he bent down and picked up the object which he had thrown upon the ground, and which glimmered faintly upon the dark surface of the heather on which it had fallen. He knew what it was, without the trouble of striking a match. It was typical of him that he handled it by the edges, and wrapped it carefully in his handkerchief before he put it in his pocket. Then he started once more on his homeward journey, his mind full of this interview with the man who called himself the Black Sailor. + 

His theory had been vindicated. During the night which had followed Inspector Hanslet’s first visit to him, he had racked his brains in the endeavour to recall the circumstances under which he had first heard the name of Copperdock. And then, at last, just before dawn, the scene had come back to him. The gloomy court at the Old Bailey, the voices of counsel, the set tense face of the prisoner in the dock. And finally, the scene when the jurymen, under his direction, had discussed the verdict which was to decide the man’s fate. Yes, he remembered the name of the little man who had seemed to share his own merciful views. Copperdock, that was it. The names of the others he did not remember, but they had seemed to be inspired with a stolid commonsense virtue. One of them had implied that if doctors thought they could get away with this sort of thing, there was no knowing what they would be up to. They were a lot of butchers as it was, always cutting people up to find out what was the matter with them. + 

Yes, he remembered the scene well enough. It had been impossible to argue with his colleagues on the jury. The majority were against him and the man Copperdock; they could only acquiesce in their opinion. The twelve had filed back to the places in court, he could see now the look of awful anxiety in the eyes of the prisoner. And then, in reply to the solemn question of the judge, he had spoken the words, “Guilty, my Lord.” + 

Morlandson had been reprieved, and, according to the notes made by Harold, must by now be at liberty. Was it possible that he had returned to the world with vengeance in his heart? The Professor had obtained permission to examine the official records of the trial, and had thus learnt the names of the remaining members of the jury. Five of them corresponded with the names which Hanslet had mentioned as the victims of the recent mysterious murders. There could be no further doubt. + 

But Morlandson had died, burnt to death in his laboratory within a year or so of his release. How was this fact to be fitted in with this theory? The Black Sailor had enlightened him upon this point. Dr. Morlandson had handed on his vengeance to this mysterious successor, whose true identity he had no means of guessing. It was true that in one direction his doubts had been resolved, but only to be replaced by a series of questions, equally imperative. Who was this man, who called himself the Black Sailor? The Professor had examined his appearance intently while the light lasted, and could see none of the obvious traces of disguise. He could swear that his most striking beard and whiskers had been genuine, and he had worn his clothes naturally, as though accustomed to them. Again, how had he known that Dr. Priestley was in the neighbourhood? The Professor was certain that he had not been followed during his journey from London. It was impossible that this man should live openly, with the reward for the Black Sailor circulating all over the country. Was it possible that he lived concealed somewhere in this desolate tract of country? And if so, how did he contrive to carry out his murders within the very heart of London? + 

These problems would wait. A more urgent one seemed to the Professor to require solution. What, he asked himself, had the Black Sailor’s object been in seeking this meeting? The Professor was quite prepared to believe that the reason he had given accounted for part of the truth. He could well imagine Morlandson, his brain turned by his fancied grievance, wishing the effects of his vengeance to become known. This was to be expected, it was merely an example of the curious vanity usually displayed by maniacs. But was there any other purpose in the meeting, which he had not yet understood? And, in any case, what course was he to take? + 

As the Black Sailor had suggested, to set the local police on the scent would be sheer waste of time. No serious attempt to scour the heath could possibly be made before daylight next morning, by which the object of the search would be far away. They might find the tracks of his bicycle, but if he desired to elude pursuit all he would need would be to carry it for some distance over the heather. The Professor credited the man who had baffled the London police by the ingenuity of his murders with sufficient acumen to leave no tracks by which he could be followed. No, the police could not help him, if he were to escape the fate that threatened him, it must be by his own efforts. + 

And so far his adversary had completely outwitted him. In spite of his own elaborate precautions, his investigations into the death of Dr. Morlandson were known and had been treated as the most natural thing in the world. For his own part, he had learnt very little that he had not known before. Certainly his theory as to the motives for the murders in Praed Street had been confirmed. This was a small satisfaction to place against the Professor’s chagrin. He had also learnt that the Black Sailor, in spite of official scepticism, was an actual person. But of his identity, or the means by which the crimes had been committed, he had learnt nothing. From the police point of view he had failed utterly, since he had failed to secure any information which could possibly lead to an arrest. + 

It was nearly eleven o’clock when the Professor saw the lights of the village in the distance, and, leaving the railway line, found the lane which led homewards. The sound of his footsteps reechoed among the silent houses, the whole place breathed an atmosphere of perfect peace and tranquillity. His recent adventure seemed to the Professor as an impossible dream, a trick of his mind, so long concentrated upon the subject. So strong was the illusion of unreality that the Professor was impelled to feel the hard outline of the counter hidden in the folds of his handkerchief. There had been something theatrical about the whole adventure; the time, the place, the man’s appearance, his voice, so curiously harsh and rasping, his very words, so utterly at variance with his character of a rough sailor. With something of a shock the Professor remembered that Copperdock had claimed to have seen him at a moment when it was proved that there was no one there. Was it dimly possible that there was something supernatural about the affair? The Professor brushed the suggestion aside as absurd. + 

The inn was closed by the time he reached it, but, remembering the landlord’s instructions, he knocked upon the door, and after a short interval the key turned in the lock and the door opened. The landlord’s voice welcomed him. “Bit later than you expected, sir, aren’t you?” he said. “Did you lose your way or anything like that?” + 

“No, the⁠—er⁠—beauty of the night tempted me to stay out of doors,” replied the Professor. + 

“Well, sir, come ten o’clock, and seeing as you didn’t come home, I put a drop of that old brandy aside for you. I hope I don’t presume too much, sir.” + 

“You did not indeed, I shall be very glad of it,” replied the Professor thankfully. + 

The landlord disappeared for a moment, and returned with a glass on a tray, which he handed to his guest. “I thought you might be glad of it after your walk, sir,” he said. “Did you find the ruins of Dr. Morlandson’s cottage?” + 

“Yes, I did,” replied the Professor quietly. “A most isolated spot. I noticed that there was a path running past it. Where does that lead to?” + 

“It doesn’t lead nowheres in particular, sir. When the cottage was first occupied, before Morlandson’s time, it led out to the Studland road. That was the only way to the place before that railway line was built. The path’s still there, is it? I should have thought it would have been growed over by now.” + 

“No, you can still trace it,” said the Professor. “And, curiously enough, there were the marks of a bicycle wheel running along it.” + 

“A bicycle!” exclaimed the landlord. “Well, to be sure! When there’s a barge lying at Goathorn the fellows on board sometimes brings bicycles and rides in here by the side of the railway line, but I don’t know what could have taken any of them past the cottage there. Perhaps one of them wanted to get to Studland, though there’s a shorter way there from Goathorn through Newton. I should have said nobody used that path, not once a year.” + 

“No, I do not imagine that this man Morlandson saw many visitors,” said the Professor reflectively. “I suppose people occasionally went to see him, though?” + 

“I don’t believe, bar the men who built the laboratory, that a soul went near the place except the super I was telling you of, sir,” replied the landlord. “Leastways, I never heard of any. Morlandson used to come in and fetch everything he wanted. If there was anything heavy, he’d bring a barrow with him. No, sir, if you’ll believe me, that man never saw a soul when he was at home, except the super. Didn’t care about meeting people, I suppose, with a past like his.” + 

“Well, he certainly chose a lonely place for his retreat,” agreed the Professor. “I do not suppose that any strangers were likely to disturb him?” + 

“Lor’ bless you, no, sir. ’Tisn’t many strangers as finds their way on to the heath, unless it’s a gentleman like yourself, out for a walk, and then they keeps to the paths. It’s not overgood going over the heather.” + 

“So I discovered,” replied the Professor. “But, on the whole, I have had a most interesting evening.” + 

XIX + 

A Discovery + 

It was quite evident to the Professor that since his presence upon the Isle of Purbeck was known to his mysterious acquaintance of the previous evening, there was no further need for secrecy as to his movements. As soon as he had breakfasted on Sunday, he put a trunk call through to London, and very shortly had Harold on the end of the wire. + 

“Yes, it is Dr. Priestley speaking,” he said. “The asp has struck, Cleopatra. Does that satisfy you? Yes, yes, I know, but circumstances have made it necessary for me to change my plans. Now listen. Put another short paragraph in the papers, to the effect that domestic reasons have made it impossible for Dr. Priestley to carry out his projected lecture tour in Australia. He was recalled by telegram from Paris, where he stopped on his way to join the Oporto at Marseilles, and will shortly return to London. Having done that, get in touch with Inspector Hanslet, and bring him to Corfe Castle by the train leaving Waterloo at 2:30 this afternoon. I will explain the reasons for asking him to come when I see him. I will meet the train at Corfe Castle station. Is that clear?” + 

Apparently it was, for after a further word or two the Professor laid the instrument down. He spent the day within the portals of the inn, to all appearances studying the contents of the Sunday papers, but actually trying to solve some of the problems suggested by his incredible meeting with the Black Sailor. + 

The train came in to time, and out of it stepped Inspector Hanslet and Harold. They glanced at the Professor enquiringly as they greeted him, but asked no questions until they were outside the station. And even then it was the Professor who spoke first. + 

“I am Mr. Deacon here, to the landlord of the inn, at least,” he said. “I will take you there and you can leave your suitcases. Register in any names you like, but do not divulge your connection with the police, Inspector. It would attract undesirable attention.” + 

Hanslet nodded, and the Professor introduced the two to the landlord as the friends he had been expecting. They left their suitcases, and then followed the Professor out into the village street. + 

“This is a most interesting country,” he said conversationally. “I should like to show you the Purbeck Hills from the distance. We have, I think, time for a walk before dinner.” + 

Hanslet nodded. “I should be glad of a stroll after sitting in the train,” he replied. “Lead on, Mr. Deacon. You know the way.” + 

The Professor took the lane which led towards the railway line. It was not until they were well beyond the outskirts of the village that he spoke. + 

“I must apologize for my recent actions,” he said at last to Hanslet. “I think you will understand them when I have explained my reasons to you. I was anxious to come here without anybody suspecting my presence. I had formed a theory as to the motive of the murders in Praed Street. Harold, my boy, tell Inspector Hanslet, as concisely as you can, the facts about the arrest and trial of Dr. Morlandson.” + 

Harold obeyed, and as he finished Hanslet nodded. “I remember the case vaguely,” he said. “But I don’t see⁠—” + 

The Professor interrupted him. “I happened to be the foreman of the jury. When you mentioned the name of Copperdock the other night, I fancied that it was familiar to me. Eventually I remembered that a man of that name had been one of the jurymen. More out of curiosity than anything else, I took steps to discover the names of the remainder of the panel. They were Tovey, Colburn, Pargent, Martin, Goodwin, and five others, whom I am informed have since died.” + 

“Good heavens!” exclaimed Hanslet. “Then you mean that this Morlandson, who was released from gaol after serving his sentence, is the murderer! Why on earth didn’t you tell me so before, Dr. Priestley? It will be simple enough to trace him. Our people at the Yard will know all about him.” + 

“They do,” replied the Professor drily. “They have a completely authenticated record of his death, which occurred five years ago. In fact, I am now taking you to the place where it happened.” + 

“But he can’t have died five years ago if he murdered Copperdock only last week!” exclaimed Hanslet in bewilderment. “There’s some mistake. There must have been two Morlandsons and you’ve got hold of the wrong man.” + 

The Professor shrugged his shoulders. “Ask our landlord, when we return to the inn,” he replied. “He is a most communicative man, and will, no doubt, be delighted to tell you the story, as he told it to me. I had the same doubts as you have expressed, and it was these doubts which brought me down here. I enquired for Morlandson’s history as tactfully as I could, and I examined the scene of his death, as I shall ask you to.” + 

“I am quite prepared to accept your statement, Professor,” said Hanslet. “How did it happen?” + 

The Professor recounted the facts of Morlandson’s life on the Isle of Purbeck, and the circumstances under which he met his death. “All these things can of course be verified,” he said, as he came to the end of his story. “It was while I was engaged in verifying them yesterday evening that I met with an adventure which can only be described as amazing. You will remember the man described as the Black Sailor, first seen by Wal Snyder at the time of the murder of Tovey the greengrocer, and subsequently by Copperdock?” + 

“The man Whyland was persuaded to issue a reward for?” replied Hanslet with a smile. “Yes, I remember. We seem pretty generally agreed that he was a myth.” + 

For a moment the Professor made no reply. They had by this time reached the spot where the track from Morlandson’s cottage crossed the railway line. The Professor stopped, and turned to Hanslet impressively. “I met him last night, about three hundred yards from this spot,” he said simply. + 

Hanslet stared at him in amazement. “You met him!” he exclaimed. “You mean you saw someone who looked like him, I suppose?” + 

“No, I met him, and had a most interesting conversation with him,” replied the Professor. “He was riding a bicycle, and since there has been no rain since last night, you will see the tracks in a few minutes. Further, he gave me this.” The Professor produced his handkerchief, unrolled it, and handed Hanslet the numbered counter. + 

“Good Lord, this beats anything I ever heard of!” exclaimed Hanslet. “What did the man say to you?” + 

The Professor gave a careful and detailed account of his adventures on the previous evening, to which Hanslet and Harold listened in silence. He finished by explaining that he had thought it useless to set the local police on the Black Sailor’s track, and Hanslet agreed. + 

“The fellow would have been miles away before you had got them to move,” he said. “Of course, I shall have to circulate his description again, in case anybody else saw him. But he can’t have gone about openly, with a reward on his head like that. Somebody would have been bound to have spotted him. It’s the most amazing story I ever heard. You don’t suppose he was pulling your leg, do you?” + 

“How did he know my name, and the names of the jurymen who served with me?” replied the Professor. + 

“Well, this case is full of most extraordinary contradictions. We’d better have a look at these bicycle tracks you speak of, it’s just possible we may be able to find out the direction in which he went off. Where did he mount his bicycle and ride away, Professor?” + 

“About a quarter of a mile along this path. Lead the way along, Inspector, and I will stop you when we reach the spot.” + 

They proceeded in single file, Inspector Hanslet leading. After about five minutes the Professor spoke. “It was just where you are standing, Inspector.” + 

The party halted, and Hanslet bent down to examine the path. The sand was in admirable condition to receive and retain an impression; firm enough to resist the force of the wind, yet not too hard to take even the lightest imprints. Hanslet, kneeling in the heather by the side of the path, looked at it closely. + 

“You’ve mistaken the spot, Professor,” he said at last. “There are no tracks here. It doesn’t look as if anybody had passed along here for a long time.” + 

The Professor frowned. “I do not usually mistake a spot which I wish to remember,” he replied. “However, it was nearly dark when I left it, and I may have made an error of a few yards. As you can see, this track leads straight to those ruined walls, which are the remains of Morlandson’s laboratory. It was in that direction that the man made off. If you follow the path, you are sure to find the tracks further along.” + 

They resumed their way, Hanslet examining every foot of the path as they proceeded. It was not until they reached the ruined posts which had marked the limits of the front garden that Hanslet turned and looked anxiously at the Professor. + 

“You are quite sure that this was the path he followed?” he asked. “I can’t see any tracks along it at all, either of your feet or of the bicycle.” + 

“Perfectly certain,” replied the Professor stiffly. “I am not likely to mistake it, especially as it would appear to be the only path in the vicinity.” + 

Hanslet nodded, and made his way through the tangled vegetation towards the ruins of the cottage. He walked carefully round the mound, then proceeded to the broken walls of the laboratory. He gazed at these for a minute or two, then turned towards his companions, who had remained on the path. + 

“I wish you would come here a minute, will you, Mr. Merefield?” he called. + 

Harold obeyed his summons, and Hanslet led him round an angle of the walls, out of sight of the Professor. “Has he been overdoing it a bit lately?” he asked in a low tone. “Overworking himself, or anything like that, I mean? I thought he looked pretty well done up when I first saw him the other evening.” + 

“Well, he’s hardly been outside the house for the last six months,” replied Harold. “He’s been busy with a new book, and I think it took it out of him a good deal. Why?” + 

“You heard that extraordinary yarn he spun us just now, about the Black Sailor and his bicycle. If the tracks showed anywhere, it would be on that path. Now here, all round this place, you can see the Professor’s footmarks. He was here all right last night, as he says. But it’s odd we can’t find traces of the other fellow. You don’t think he can have dreamt it, do you?” + 

“It would be most unlike him,” replied Harold. “Why should he imagine such a thing, anyhow?” + 

“Well, you see, if this jury business is correct, he is the only survivor. You remember his telling us the other day in town that there would be one more murder? He meant that his own life was threatened, and I expect it’s been preying on his mind. It’s the only way I can account for this business.” + 

Harold shook his head. “It is true that he hasn’t been quite himself lately,” he replied. “But I don’t think he’s got to the stage of seeing things. Anyhow, how do you account for the counter he gave you just now?” + 

“How do you account for anything in this blessed case?” retorted Hanslet. “I believe the devil’s at the bottom of it, if you ask me. I wish you would follow up that path in the opposite direction for a bit, while I poke about here. If you find the marks of a bicycle wheel, don’t touch ’em, but come back and tell me.” + 

Harold followed the path for half a mile or so in the direction of the Studland road, and returned shaking his head. Hanslet had by this time finished his inspection of the ruins. He turned to the Professor, who had joined him. “Well, there’s nothing very definite to be seen here,” he said, with his usual cheerful smile. “What do you suggest we do next, Professor?” + 

“Return to the inn for dinner,” replied Dr. Priestley. “Tomorrow, if you agree, I propose to return to London by an early train.” + 

“I think that will certainly be the best course,” agreed Hanslet. “I will just run round to the local police station after dinner, and have a chat with whoever’s in charge. We must certainly follow up this valuable clue of yours.” + 

They returned to the inn, and after dinner Hanslet went round to the police station. The superintendent who had been in charge at the time of Morlandson’s death had since been promoted and had left the district, but Hanslet had no difficulty in verifying the story as told by the landlord. He had disclosed his identity, and explained that he had come down in connection with a case in which he was interested, without however mentioning the Praed Street murders. In the course of conversation with the sergeant in charge he elicited the information that no strangers had recently been heard of in the district, and certainly nobody in any way resembling the Black Sailor. + 

“There’s a few foreigners and the like comes in to Poole, sir,” the sergeant had explained. “But they never comes over this way. The barges what goes up to Goathorn are all local craft, and there’s never a stranger among them. If any stranger was wandering about the heath, we’d get to hear of it, sharp enough. Why, it’s an event in the lives of these clay-workers if they see a strange face.” + 

“Well, if you should hear of a strange man with a bicycle having been seen, you might let me know,” said Hanslet. “Good night, sergeant, I won’t trouble you any further.” + 

Hanslet left the police station, more convinced than ever that the Professor was suffering from some temporary aberration. He had known such cases before, where overwork had caused the queerest effects. It was quite understandable. The Professor had certainly discovered the motive for the murders; it could not be a coincidence that all the men who had died had served on this particular jury and had been the victims of this mysterious murderer. But, having discovered this, and realizing that he was the only survivor, the Professor must have received a shock which had unduly stimulated his imagination. This was all that Hanslet could make of it. Meanwhile he determined to keep a very close watch over the Professor, for, if his theory was correct, his life was undoubtedly threatened, Black Sailor or no Black Sailor. + 

The party returned to London on the Monday morning, and Hanslet immediately went to see Whyland, whom he had left in charge during his absence. At the police station he was told that he had gone to see Mr. Ludgrove, and thither Hanslet followed him. + 

He found Whyland and Ludgrove seated in the latter’s sanctum, and the herbalist greeted him warmly on his entrance. “Come in, Inspector,” he said. “Mr. Whyland and I are talking about the death of Mr. Copperdock. As you see, I am still alive, in spite of my numbered counter.” + 

“So I see,” replied Hanslet. “You’ve seen or heard of nothing suspicious, I suppose, Whyland?” + 

“Not a thing,” replied Whyland. “Mr. Ludgrove and I set a little trap, but nothing came of it.” + 

“Oh, what was that?” enquired Hanslet. “Did you wander about Praed Street with counters stuck on your backs, or what?” + 

“Better than that,” said Mr. Ludgrove with a smile. “Of course, you realize that five out of six of these deaths have taken place in Praed Street, don’t you? Well, another thing is that they have taken place during the weekend. It was a fair inference that if my life was to be attempted, it would be during the weekend, and in Praed Street. Do you agree?” + 

“Well, it sounds reasonable, anyhow,” replied Hanslet. “What about it?” + 

“I felt as though a breath of country air would do me good,” continued the herbalist. “As Inspector Whyland may have told you, I usually try to spend a weekend out of London at least once every three weeks. For one thing it does me good, and for another my business obliges me to collect herbs from time to time. And I happen to have heard of some particularly fine colchicums growing near Dorchester.” + 

“Mr. Ludgrove told me this, and I thought it wouldn’t do him any harm to go and look for these collycums, or whatever he calls them,” broke in Whyland. “Besides, his suggestion gave me an idea. So we smuggled him off to Paddington, where two of my plain clothes men saw him into a train on Saturday morning. I reckoned he’d be safe enough out of London. Then I stayed here, being careful to keep a light burning in the shop, so as people would think Mr. Ludgrove was in residence. Then we met Mr. Ludgrove’s train at Paddington yesterday, evening, and brought him back. But, as I say, nothing happened. I only had one visitor all the time, and that was young Copperdock, on Sunday morning. I explained to him that Mr. Ludgrove was upstairs, and he said he would look in again later. But he never came, at least while I was here.” + 

“Well, it wasn’t a bad notion, certainly,” said Hanslet. “I don’t think I should go about alone too much, if I were you, Mr. Ludgrove.” + 

The herbalist smiled. “I hardly get the chance,” he replied. “I have a habit of taking a brisk walk in the neighbourhood every evening. During this last week I have never gone more than a few steps before being accosted by a charming and talkative individual who insists upon accompanying me. I am not complaining, I have found his conversation most interesting.” + 

“And he yours, Mr. Ludgrove,” laughed Whyland. “I’m sorry, but what can we do? I don’t want to alarm you, but you know there is the chance that an attack might be made upon you. And that attack would give us the clue we want.” + 

“I see. I am to be used as a stalking-horse,” said Mr. Ludgrove. “Well, I have no objection. I am only too glad to be of service in unravelling this terrible mystery.” + 

Hanslet, who had been silent for a moment or two, suddenly turned towards Whyland. “You say that nobody came near you while you were alone here but young Copperdock. What did he want, I wonder? Have you seen him since you came back from your herbalizing expedition, Mr. Ludgrove?” + 

A grave expression spread over the herbalist’s face. “I have,” he replied. “It was for this reason that I asked Inspector Whyland to come here and see me. I was about to tell him the story when you came in, and I realized that it would be better if you heard it together. Ted Copperdock came here yesterday evening, about an hour after my return.” + 

“Oh, he did, did he!” exclaimed Hanslet. “What did he want?” + 

“He told me he had come round in the morning to ask me if I would go through his father’s belongings with him. Finding me busy, as he supposed, he went back home, and started to go through them by himself. He spent the whole afternoon sorting out Mr. Copperdock’s papers, and it was not until late that he began to look over his clothes. In the pocket of one of his coats he discovered something which, as he himself said, terrified him. He came to me at once, and begged me to come back with him. He was so insistent that I broke the promise which I had made to Inspector Whyland, not to go alone into any house in Praed Street, and went upstairs with him into his father’s bedroom. There he showed me an overcoat hanging in a cupboard, and in the pocket of it⁠—this!” + 

The herbalist rose, walked to the bench at the far end of the room, and pointed to an object wrapped loosely in paper. Hanslet and Whyland followed him, and the former unwrapped the paper carefully. As the object appeared, they both uttered a startled exclamation. It was the blade of a knife, and with it a long wooden handle, with a hole running the whole of its length, and fitted with a setscrew. + 

Whyland bent over it with a look of triumph. “I knew it, all along!” he exclaimed. “Look at this blade! It is exactly similar to the ones found in the bodies of Tovey and Pargent. You see the dodge, don’t you? This blade just fits the hole in the handle. It’s meant to be pushed through and gripped by the setscrew. But, if you tighten the screw as far as it will go first, then put the blade in, it is held lightly, just by its very end. Now, if you stab a man with the blade fixed like that, what happens? The blade goes in all right, and there it stays, while you walk away with the handle. It’s beautifully simple, and you leave no fingermarks behind you.” + 

But Hanslet stared at the knife in silence, his brain a whirl of conflicting theories. If the Professor was correct in his assumption, Copperdock was a victim of the unknown assassin. How did this knife, which, as Whyland said, was exactly similar to those with which Tovey and Pargent had been killed, come into his possession? On the other hand, if Copperdock had been the murderer, what became of the Professor’s theory? Why should one of the jurymen wish to murder his colleagues? The problem became more complicated with every fresh discovery. + 

“This blessed case would drive an archangel to drink,” he observed disgustedly, as he wrapped up the knife again and put it in his pocket. “Well, we’d better go across and see what young Copperdock has to say about this, eh, Whyland?” + 

XX + 

Mr. Ludgrove’s Invitation + 

April gave place to May, and May to June, with no further development in the mystery which surrounded the Praed Street murders. The discovery of the knife in the pocket of Mr. Copperdock’s overcoat, combined with the fact that although Dr. Priestley and Mr. Ludgrove had each received a numbered counter, they had not so far been menaced by any particular danger, had convinced the police that the secret had died with Mr. Copperdock. A very careful examination of the handle showed that it bore his fingermarks, and his son, although he could not account for its presence where he had found it, was emphatic that it could not have been placed there since the night of his death. + 

The Professor made no reference whatever to the case, either to Harold or to Hanslet. The latter during his infrequent visits to the house in Westbourne Terrace, made no reference to the case. He was becoming more and more convinced that the Professor’s interview with the Black Sailor had been a pure hallucination; that the Professor, having imagined the sequel to his theory of the jurymen, had somehow been under the illusion that the events of his imagination had actually taken place. In his own mind, however, he was by no means satisfied with the official view of the matter, of which Whyland was the principal exponent. It left so much to be explained, chiefly Copperdock’s motive, to say nothing of his methods. To begin with, how had he contrived to murder Mr. Tovey, when at the moment of the latter’s death he was sitting comfortably before his own fire? And, if the answer to this was that he had accomplices, who and where were they? + 

However, his superiors appeared to be satisfied, and, towards the beginning of June Hanslet went off upon his long postponed leave. The Professor’s time was fully occupied in correcting the proofs of Some Aspects of Modern Thought, which were now coming in from the printer, whose reader, appalled by some of the Professor’s strictures upon his contemporaries, had scattered here and there across the margin the ominous words “Query, libellous?” To each of these the Professor added the note: “Nonsense!” in letters half an inch long at least. It was perhaps fortunate for the conscientious reader that he was beyond the reach of the Professor’s tongue. + 

The rigid police protection which had at first been imposed upon both the Professor and Mr. Ludgrove had been gradually relaxed until now it had dwindled to nothing more serious than a casual glance at their houses by the constable on beat when he happened to pass them. The professor himself appeared to have forgotten the warning given to him by the Black Sailor, and to have acquiesced in the official view that, since the perpetrator had committed suicide, nothing further would be heard of the murders. + 

It was while matters were in this state that Dr. Priestley received one Saturday morning a letter which obviously caused him some satisfaction. It was signed “Elmer Ludgrove” and was written in a curiously neat and clerkly hand. The contents of it were as follows: + 

Dear Sir. I should not venture to write to you, but for the fact that I know that you are as interested in the recent affair of the numbered counters as I am myself. I have recently come across, wholly by accident, certain curious facts which may serve to throw an entirely fresh light upon the deaths of six men, which, to my mind, have not yet been satisfactorily explained. I am not anxious to approach the police, at least until I have consulted you. The police, as is perhaps natural, could scarcely be expected to welcome disclosures which would completely upset their official theory. They believe, as I confess I did at one time myself, that the late Mr. Copperdock was guilty, and that his mania finally culminated in his own suicide. + 

If I am correct in my deductions from the new evidence which has come into my hands, I can prove beyond question that Mr. Copperdock was innocent, indeed, that he himself fell a victim to the agency which committed the other murders. I must ask you to respect my confidence until you have allowed me to put my evidence before you. When this has been done, I shall ask your advice as to the best means of laying it before the authorities. You, I have reason to believe, are on friendly terms with Inspector Hanslet, and perhaps you will agree, when you have examined the evidence I shall put before you, that it will be best to call him into consultation. + 

I suggest, as the various exhibits to which I shall be compelled to refer are at present at my house, and as it may be necessary for me to point out to you certain peculiarities of the locations in which the murders took place, that your examination be carried out there. As I believe that as little time as possible should be wasted, I suggest, if it meets with your approval, that you should do me the honour of calling upon me this evening. As, in the light of recent events, you may not care to come to Praed Street alone, I propose to call upon you after your dinner this evening, and to learn your wishes in the matter. If you agree to my suggestion, we can then walk to my house together. I am, sir, yours faithfully, + 

The Professor read this letter through twice. His final conclusion was that this man Ludgrove had in some way discovered that the dead men had all been members of the Morlandson jury. After all, he knew from the Black Sailor’s words that Ludgrove had made inconvenient enquiries, and it was possible that he had somehow stumbled upon the truth. Anyway, there could be no harm in going to see him and hearing what he had to say. Besides, he had never conveyed to him the Black Sailor’s warning. Hanslet might have, but the Professor, who had penetrated the ill-concealed scepticism of the Inspector, considered this unlikely. In any case, by comparing notes with this man, who had been living in Praed Street throughout the period of the murders, he might derive a hint which would lead him to his goal. + 

For Dr. Priestley, although he appeared to have put the whole affair out of his mind, was in fact determined to find the solution of the problem. He felt that so far the part he had played had been a distinctly ignominious one. Both his theory of the motive of the crimes and his account of his meeting with the Black Sailor had been disregarded. And although Dr. Priestley affected to regard his excursions into the solution of criminal problems with half-amused tolerance, his ill-success hitherto in this instance was a secret, but none the less bitter, blow to his pride. + 

Yes, he would certainly go to see this man Ludgrove. His letter showed him to be a man above the ordinary standard of education of people in his position. Hanslet had spoken of him as a man of considerable intelligence. The Professor, considering the matter, felt that he might well have got into touch with him before. He began to think that he had been too ready to rely upon the police descriptions of the events which had taken place, and had neglected an alternative source of information which might contain many details of value. And, his determination made, the Professor fidgeted all day until, having hurried through dinner and found himself in his study earlier than usual, he could expect his visitor. + 

Mary had been instructed to show him straight in, and, when he was at length announced, the Professor rose at once to greet him. Mr. Ludgrove, seen for the first time, was certainly an imposing and dignified figure. His snowy white hair and beard gave him a patriarchal appearance, produced an almost severe impression, which was only modified by the kindly smile which habitually hovered at the corner of his mouth. His eyes were screened by his powerful spectacles, but one guessed them to be direct and piercing in their expression. + 

“I am delighted to meet you, Mr. Ludgrove,” said the Professor warmly. “Yes, I am Dr. Priestley, and this is my secretary, Mr. Merefield. I received your letter, and am much obliged to you for your suggestion, which I shall be very glad to fall in with.” + 

“Thank you, Dr. Priestley, you are very kind,” replied Mr. Ludgrove, in his deep and pleasant voice. The Professor glanced at him in astonishment. Neither the voice nor the intonation were such as he would have expected of a herbalist in Praed Street. + 

“It is a beautiful evening,” continued Mr. Ludgrove. “Shall we walk to my house, or would you prefer to call a taxi? I know that the vicinity of Praed Street has a bad reputation as a result of these deaths, but although, as you probably know, I received a numbered counter some weeks ago, I have so far come to no harm. You need have no apprehensions once we reach my house. The police still display considerable concern for my safety.” + 

Mr. Ludgrove smiled, and even the Professor’s set features relaxed a little. “I am not afraid to walk to Praed Street, especially in your company, Mr. Ludgrove,” he replied. + 

“And coming back?” persisted the herbalist. “I fear I have no telephone, and it may take me some minutes to find you a cab. I should be happy to walk back here with you.” + 

The Professor made an impatient gesture. “Believe me, Mr. Ludgrove, I am no more afraid of Praed Street than you are. If you insist upon walking home with me, I shall be very glad of your company. If not, I am perfectly capable of taking care of myself.” + 

“It will be late, I am afraid, that is, if you have the patience to listen to me for so long,” replied Mr. Ludgrove. “I shall be compelled to inflict upon you a long and possibly tedious tale. However, you shall decide how much of it you wish to listen to.” + 

“I am usually considered a good listener,” said the Professor. “Shall we walk to your house, Mr. Ludgrove?” + 

The herbalist assenting, they left the house and walked down Westbourne Terrace together. Mr. Ludgrove’s shop was scarcely half a mile away, and they covered the distance in a few minutes, conversing about anything but the matter uppermost in their thoughts. The Professor found Mr. Ludgrove a most entertaining companion, and found himself wondering what such a man was doing to be compelled to keep a shop in such an odd neighbourhood. + 

They walked down Praed Street without adventure, and Mr. Ludgrove unlocked the door of his shop with his latchkey. They passed through it into the inner room, the window of which was already curtained and the gas lighted. Dr. Priestley cast a swift glance round it, noting with interest the scientific instruments on the bench, the cases full of books, and two comfortable armchairs. “This is a very comfortable room of yours, Mr. Ludgrove,” he remarked approvingly. + 

“It has heard some queer stories in its time,” replied Mr. Ludgrove with a smile. “You can form no idea of the extraordinary confessions which some of my clients force me to listen to. But I can assure you that it has heard nothing more amazing that the story which I am about to unfold to you this evening.” + 

“May I ask a question before you begin, Mr. Ludgrove?” said the Professor quietly. + 

“Certainly, pray ask as many as you please,” replied Mr. Ludgrove with a smile. + 

“How did you learn of my interest in this affair? So far as I am aware, it is not common property.” + 

“I am afraid that Inspector Hanslet was indiscreet,” replied Mr. Ludgrove. “When he first took over the case, he came here and had a long talk with me. He said then that he would put the facts before one whose powers of deduction were unrivalled. When I next saw him, he happened to mention your name, which I already knew as that of the boldest and most enterprising scientist of the age. It required very little intelligence on my part to infer that you would be interested in these extraordinary happenings, and that you were scarcely likely to accept the official explanation of them.” + 

“I see,” said the Professor. “Well, as it happens, your inference is correct. I am greatly interested, and I have a theory of my own as to the motive for the murders, which the police have been pleased to reject. I am all the more anxious to hear the evidence you have to put before me. There is still one more point in which I am interested. I am informed that, sometime before his death, Mr. Copperdock reported that he had met an individual known as the Black Sailor. Upon this being reported to you, you stated that you happened to have Mr. Copperdock under observation at the moment when he stated the meeting took place, and that no Black Sailor was present. Is this correct?” + 

“I can assure you, Dr. Priestley, that at that moment there was nobody in sight but Mr. Copperdock and myself,” replied Mr. Ludgrove simply. + 

“Thank you,” said the Professor. “Now, I am prepared to examine the evidence you have to show me.” + 

Mr. Ludgrove rose from his chair. “Will you excuse me for a few minutes, Dr. Priestley?” he said. “Before I begin my explanation, I should like to fetch certain things which I have put in a place of security upstairs. I will not keep you very long.” + 

He passed into the shop as he spoke, and the Professor could hear the sound of his footsteps as he climbed the stairs. The Professor, left alone in the room, proceeded to examine the titles of the books in the shelves. They were mainly botanical works, such as one might expect to find in the library of a herbalist. But here and there among them were a few volumes of general scientific interest. Dr. Priestley smiled as he saw, lying inconspicuously at the end of one of the shelves, a work he had published a year or so before, Fact and Fallacy. No doubt this had given Ludgrove the cue to his own interest in a problem so intricate as that of the Praed Street murders. + 

Lying next to it was a book bearing the name of an author well-known in the scientific world, which the Professor had never heard of. He took it up and began to turn over the pages with interest. His eye caught a passage dealing with one of the subtler mathematical problems raised by a particular aspect of relativity. He became absorbed in this, forgetting all about Mr. Ludgrove and his promised demonstration. So he remained for several minutes, until he had read the passage from beginning to end. Then, all at once, he became conscious that he was no longer alone in the room, that somebody was standing just inside the door, awaiting his pleasure. The Professor laid the book down, and turned on his heel, an apology upon his lips. But the words died in his throat, and he stood for an instant staring at the figure with unbelieving eyes. + 

It was the Black Sailor. + 

XXI + 

An Explanation + 

The Professor’s first startled thought concerned the manner in which the man had entered the room. He had heard no sound of his entry, and he remembered that Mr. Ludgrove had been careful to lock the door of the shop when they had come in together. His second was a sudden thrust of anxiety for Mr. Ludgrove’s safety. In the complete silence of the little room, into which no sound penetrated but the faint low rumble of the traffic outside, he listened for the sound of his footsteps above. But, even to his keen ears, the house seemed as quiet as the grave. + 

It was the Black Sailor who broke the silence. “Sit down, Dr. Priestley,” he said gravely. “I have much to say to you. You will recall that this is our second meeting.” + 

But Dr. Priestley took a step forward, and stared into the man’s face, at his jet-black beard and hair, at the scar which gleamed angrily upon his cheek. He wore a woollen cap, drawn over his face, and a blue pilot coat over his jersey. But for these details, he was dressed as he had been when the Professor had met him upon the Isle of Purbeck. And the tones of his rasping voice sent a thrill of fear through even the Professor’s determined heart. + 

“How did you get in here? Where is Mr. Ludgrove?” The Professor found his voice at last. + 

“Mr. Ludgrove is dead,” replied the Black Sailor, almost gently. “Surely you remember the warning I gave you when we last met? Mr. Ludgrove, the herbalist of Praed Street, is dead. Nobody on this side of the grave will ever see him again. But you shall not be disappointed, Dr. Priestley. He was to have explained to you many things that seemed obscure, but were in reality very simple. It is only fitting that I should take his place.” + 

And then at last the Professor understood. Perhaps it was some note in the man’s voice that gave him the clue. The solution was so simple that he could have laughed aloud at his own lack of perception. “You are Mr. Ludgrove,” he said simply. + 

The Black Sailor laughed quietly, and the laugh and the voice in which he replied were those of the herbalist. “So you have guessed at last, Dr. Priestley!” he exclaimed. “Oh, but it was so simple! A little dye, which could be applied or removed in a few minutes, a little greasepaint for the scar, an artistic disarrangement of my beard and hair, a change of clothing, and who would recognize Mr. Ludgrove the herbalist? Still, the Black Sailor was careful only to appear in the half light. His disguise might have been penetrated under more searching conditions. But I flatter myself that it is effective.” + 

The Professor, looking at the man, was forced to agree. Even now that he knew, he found it difficult to recognize the venerable Mr. Ludgrove with his well-kept, snowy beard, his kindly smile, and his large spectacles, in this wild-looking sailor with the fierce face and the tangled black hair which seemed to cover it. The disguise was undoubtedly effective, but⁠—how simple! + 

“Mr. Ludgrove is dead. His mission is completed, and you will never see him again,” continued the Black Sailor. “Let us do his memory the justice of saying that he told the truth. When Copperdock saw the Black Sailor, it was perfectly correct for Ludgrove to say that he and Copperdock were alone in the street. Ludgrove was the Black Sailor that evening. But this is beside the point. Pray sit down, Dr. Priestley, and we will enter upon the explanation which I have to give you.” + 

Dr. Priestley’s mind had been working rapidly while the man spoke, and it appeared that he had guessed the Professor’s thoughts. + 

“Perhaps I should explain the conditions,” he continued. “All the entrances to this room are securely fastened. The door is locked, and, as you see, there is a heavy curtain across it. The window is boarded up, and there are no other openings. If you were to shout as loud as you cared, no one could possibly hear you. Please do not think I wish to threaten you, Dr. Priestley, but I would point out that if you were so unwise as to attempt personal violence, I am a very much more powerful man than you, and I am armed. I am afraid that there is no alternative for you but to listen to what I say. And after that will come release. Now, surely you will sit down, Dr. Priestley.” + 

The Professor, after a glance round the room, perceived the helplessness of his position. The man was clearly mad, but his mania was strictly limited. Upon most subjects he was sane as he was himself. He must perforce listen to what he had to say. Perhaps, during the time which this would occupy, he might be able to evolve a scheme for his capture. He walked across the room and sat down in the chair which the Black Sailor pointed out to him. + 

The man immediately took the chair opposite. “Artists are naturally vain, Dr. Priestley,” he began, “and I think my exploits entitle me to consider myself an artist. I have long promised myself the pleasure of recounting them to one who would appreciate their ingenuity, and you are the very man for such a purpose. I have, I believe, read everything that you have written, and I have understood a nature which revels in ingenious methods. I flatter myself that what I have to tell you will, at least, not bore you.” + 

“I shall be extremely interested to hear it,” replied the Professor quietly. + 

“Before Dr. Morlandson died, he furnished me with a list of his intended victims, and a very fine collection of lethal apparatus,” continued the Black Sailor. “My first concern was to find some spot in London from which to operate. I made careful enquiries as to the present addresses of the surviving jurymen, and found that most of them came from this part of London. This, of course, was not coincidence, since juries are frequently called by districts. + 

“I therefore determined to establish myself in this neighbourhood. I knew enough of the properties of herbs to set myself up as a herbalist, and I was fortunate enough to find this empty shop, almost opposite the premises of one of my intended victims. Once in possession of it, I set myself to develop a business which should bring me into contact with all the gossip of the neighbourhood, and to study the habits and circumstances of my intended victims. My own apparent vocation I tried to make as open as I could. My shop was available to any who cared to enter it, and from the first I accustomed the acquaintances which I made to my habit of spending occasional weekends in the country, and of taking a walk every evening, since I foresaw that these would be essential to my purpose. And in Mr. Copperdock I found a simple and not over-intelligent personality who would serve me admirably as a dupe upon whom suspicion might be cast. + 

“You will, I think, understand the task which I had been set. I was to execute the vengeance of Dr. Morlandson upon the men who had condemned him to so many years of agony. But this must be done in such a manner that their deaths would not be attributed to pure chance, but must eventually be made to appear as acts of justice, as indeed they were. I could not employ the same methods in each case, but at the same time I wished each death to carry the same distinguishing mark. + 

“I was at first puzzled to think of any such mark. And then, during a visit to Mr. Copperdock, the idea came to me. I saw a box full of white bone counters lying on his table, and I managed to appropriate a dozen or so of these. At the same time I carefully noted the envelopes he used in his business, and by a casual question learnt where he had obtained them. I bought three thousand of these, all the remaining stock, giving the name of Mr. Copperdock. There was very little chance of their being traced, but if they had been, the result of inquiries would have shown that they had all been sold to the tobacconist. + 

“I also discovered that the typewriter recently purchased by Mr. Copperdock was a Planet, and I took a careful note of the brand of pen and red ink he habitually used. I next made enquiries among the envelope addressing agencies, until I found one which employed Planet machines. To this agency I sent my envelopes, together with a telephone directory in which I had marked some two thousand names, among which were those of my intended victims who happened to have a telephone. To this list I added one of my own, containing a thousand additional names, among them the jurymen I had not found in the telephone book. I instructed the agency to type these names and addresses on the envelopes. It was a safe assumption that a year later, when I began operations, the agency would not remember having typed the names of the dead men among so many thousands of others. The counters I numbered myself, as required. + 

“Last November, I felt myself in a position to seek my first victim. I decided that it should be Mr. Tovey, a personal friend of Mr. Copperdock, from whom I had learnt all I required to know about his habits. I had, among my other weapons, a paper cutter’s knife, with half a dozen blades. These blades I had sharpened along both edges until they resembled daggers, and I had discovered a means of fixing them lightly into the handle, so that they would remain in the wound, leaving me free to carry off the handle. + 

“That evening, Mr. Ludgrove took his usual walk, returning by way of Paddington station. From here he telephoned to Mr. Tovey, giving him the message that he was wanted at St. Martha’s. Mr. Ludgrove then walked back here, and took on the character of the Black Sailor. Behind this shop is a piece of ground which was once a garden, and that in turn is separated by a low wall from a yard, deserted after business hours, with gates and also a small door leading into a back street. I had made myself a key to the small door, and it provided me with an alternative means of access to this house. + 

“The Black Sailor went out this way, waited in the shadows at the corner of the back street until he saw Mr. Tovey pass, then followed him and caught him up among the crowd outside the Express Train. The knife required no violence in its use, merely a firm push in one of the spots which Dr. Morlandson had shown me. The actual stabbing was a very simple matter, and the Black Sailor disappeared in the crowd, to return here by the way he went out and transform himself into Mr. Ludgrove. + 

“But I realized that this method, although it had served its purpose once, was inartistic and dangerous. There was always the risk that the Black Sailor might be recognized and traced back here. As a matter of fact, Wal Snyder had noticed him, but his evidence was discredited. The police, however, were compelled to offer a reward for him, and I determined that the Black Sailor must be reserved for special purposes. + 

“In the case of Mr. Colburn I adopted quite a different method. I had become a customer of his, and had encouraged his son to confide in me. From him I gradually learnt his father’s habits and peculiarities, particularly that of smoking a pipe in the shop after lunch, and, when he had finished it, of refilling it and putting it away on a shelf. I examined the pipe in young Colburn’s absence, and noticed that it was cracked. That evening, I visited a tobacconist at some distance from here and bought a pipe of similar make and shape. + 

“Within a few days, as I had expected, I saw Mr. Colburn enter Copperdock’s shop. It was a fair assumption that he had gone in to buy a new pipe to replace the old one, since I had learnt that his tobacco was always delivered to him. I took a very small splinter of glass, covered it with a preparation which Dr. Morlandson had given me, and drove one end of it into a notch I had made in the mouthpiece of the pipe I had bought. I then went to Colburn’s shop, on an errand which necessitated young Colburn’s going to the bakehouse and leaving me alone. I saw, as I had expected, a new pipe lying filled on the shelf. I substituted mine for it, put Mr. Colburn’s pipe in my pocket, waited until young Colburn came back with my purchase, and left the shop. I was in the country when Mr. Colburn died, but I heard the details later, as no doubt you have heard them, Dr. Priestley.” + 

“Yes, the deaths of Colburn and Martin strengthened my theory that Dr. Morlandson was at the bottom of the affair,” replied the Professor calmly. “I guessed that there was extensive medical knowledge behind both of them.” His one idea was to prolong this recital as much as possible. + 

“You will agree, however, that it would have been impossible to trace Mr. Colburn’s death to me. By this time I had come to the conclusion that it would be as well to stage the scene of my executions as far as possible in Praed Street. I wished to concentrate attention upon this particular district, since I knew that the obvious effect on the police would be to suggest to them an inhabitant of it. As soon as they did this, I was ready to supply a number of hints and inferences. I was thus able to become on confidential terms with Whyland, and, by making a friend of him, to put myself above suspicion. And all the time I was influencing his mind in the direction of Mr. Copperdock. It was a most interesting psychological study, I can assure you. + 

“Pargent, whom I determined to tackle next, presented an entirely different problem. He lived some distance from Praed Street, and though I might have devised some means of killing him in his own home, I was most anxious to adhere to the rule I had laid down. It was not until I had carefully considered his habits that I saw my way clear. During the years which I had spent observing my victims, I had discovered the regularity of his visits to his sister at West Laverhurst. And in this regularity I saw my opportunity. + 

“One Saturday morning, when he was due to go to West Laverhurst, I went down from Waterloo to Penderworth, for which the station is Wokingham, ostensibly to collect plants. I went to Waterloo by way of Paddington and the tube, the most obvious way of getting there. But at Paddington I called at the booking-office, and took a ticket to Reading. Having arrived at Penderworth, I made myself as conspicuous as possible at the inn, in the character of Mr. Ludgrove, and then went out with a suitcase, with the declared intention of collecting plants. In the suitcase were my dyes and paints, also a change of clothing. + 

“Now, Penderworth is four miles from Reading, where the train stopped by which Pargent habitually returned home. I found a convenient coppice, in which I got myself up as a man with iron grey beard and hair, and a conspicuous mark upon my face. I left my suitcase in the coppice, carefully hidden, and in it Mr. Ludgrove’s clothes and spectacles. Then I walked to Reading and caught the train in which Pargent was travelling. On our arrival at Paddington I followed him through the station, and was by his side when he made his dash across Praed Street to catch the bus. My opportunity came on the refuge, and I employed the same method as I had done in the case of Tovey. + 

“I had ascertained that a train left for Reading ten minutes after the arrival of the train by which I had travelled up. I had just time to catch this⁠—I already had the ticket which I had purchased in the morning. As the train neared Reading, I went to the lavatory and removed the dye and paint. From here I stepped out on to the platform and passed the barrier unremarked. Even had I been noticed in London, and my description circulated, I thus ran very little risk. The most noticeable thing had been the ‘port-wine mark,’ and this of course had vanished. I walked to the coppice, buried the clothes I was wearing, resumed the apparel of Mr. Ludgrove, and returned to the inn with my suitcase full of the first plants I could lay my hands on. I had apparently an excellent alibi. + 

“With the death of Pargent, the curious coincidence that all three victims had received counters came to light, as I had anticipated it would. I thought it wise to suspend my operations for a while, while I prepared my plans for dealing with the remainder of the surviving jurymen. Goodwin presented the greatest puzzle. He was confined to his house, almost to one room, and I despaired of being able to reach him. I had nearly decided to leave him alone, knowing that his death could not be delayed very long in any case. But I had a sudden inspiration. The numbered counters had attracted a good deal of attention, and the sequel to their receipt was well known. It was quite possible that Goodwin, to whom any shock was likely to be fatal, would die as the mere result of finding one in his post. I made the experiment, and it was successful. But I claim no great credit for this exploit. I might well have failed, had fortune not favoured me, and I was compelled to abandon Praed Street as the scene of his death. I have always considered that the execution of Goodwin was not up to my usual standard. + 

“But I have omitted the case of Martin, upon which I rather pride myself. Put yourself in my position, Dr. Priestley. Here was a man, living in the suburbs, and having an office in the City. How was I to lure him to Praed Street, and ensure his death when he arrived there, at a time when Praed Street had already gained notoriety as the scene of three mysterious deaths? I knew quite a lot about Martin, more than most people, in fact. I knew that he had once been in business in Praed Street, and that he had prospered there rather more rapidly than his apparent business warranted. My connection among the shadier classes in the neighbourhood helped me there. I discovered, hint by hint, that he was a well-known fence, a receiver of stolen goods, that is, Dr. Priestley, and that discovery, coupled with the fact that the premises he had once occupied were again changing hands, gave me an idea. + 

“My first move was to make the acquaintance of the builder who was carrying out the alterations to Number 407, and from him I learnt in the course of conversation the name of the new tenant. He asked me to come and look at the place, an invitation which I accepted without too great a show of eagerness. In the next few days I visited the place again, more than once. I wanted the builder’s men to get accustomed to the sight of me. For this purpose I was Mr. Ludgrove the local resident, of course. As a matter of fact, most of the builder’s friends went to have a look at the place. There is always an interest in vacant premises in a street like this. + 

“Dr. Morlandson had provided me with a number of celluloid capsules, containing pure prussic acid. I took an ordinary electric lamp, broke it, and connected the ends of the leading-in wires by a piece of fine foil, which would become red hot on the passage of a current. Round this I wrapped a few strands of nitrated cellulose, and to this I fixed the celluloid capsule. The action of this device was very simple. If a current were passed through it, the cellulose would inflame and set fire to the capsule, thus releasing the prussic acid. Some of the vapour of this might catch fire, but enough would be left to be fatal to anybody breathing it in a confined space. And I knew of a confined space most suitably adapted to the purpose. + 

“I wrote a letter to Martin, which I knew could not fail to bring him to Number 407, and to bring him alone. It suggested that somebody had discovered his true occupation, and was prepared to keep the matter secret, for a consideration. Then, on the Saturday morning, just before the men were due to leave, I walked openly into Number 407. I had kept an eye on their habits, and knew that before they left they packed away their tools in the back room on the ground floor. I could hear them there as I went in, and I made my way down to the cellar without anybody noticing me. All I did there was to put my poison device in the lamp holder in the small cellar⁠—I had heard the electrician tell the builder that the current would be connected that day⁠—hang the numbered counter on the switch, and remove the string by which the swing door could be pulled open from within. The trap was set, it remained only to ensure that Martin should have easy access to it. + 

“I knew about the arrangement whereby the keys were kept at the sweet shop. I had announced that I was going into the country that day, travelling into Essex by the London, Tilbury and Southend from Fenchurch Street. I took the Underground, apparently to Aldgate, but got out at Aldersgate Street. From here I walked down the Barbican, saw Martin leave his office, go to lunch, and finally book at Aldersgate Street to Praed Street. I immediately telephoned from one of the boxes there to Mr. Briggs, who had the keys, saying that I was the tenant of Number 407, and asking him to look out for a Mr. Martin, and give him the keys. I then went on to Fenchurch Street, spent a happy and profitable day in the country, and returned home to hear of the death of Mr. Martin. I was, I confess, slightly annoyed to find that it had been attributed to suicide. But then, I had never anticipated that Martin would bring an automatic with him. But perhaps I weary you with these details, Dr. Priestley?” + 

“Not in the least!” replied the Professor fervently. He glanced furtively at the clock. It was already past ten o’clock. + 

XXII + 

The Death Chamber + 

“What I have to tell you now may interest you more nearly, Dr. Priestley,” continued the Black Sailor. “Having disposed of five of my intended victims, I had to remove Copperdock. But I wished first of all to concentrate as much suspicion as possible on him before his death. You will perceive the idea, no doubt. If the murders were to cease with Copperdock’s death, there being already a vague suspicion that he had caused them, further enquiries would not be pursued very briskly. + 

“For this reason, I appeared to Copperdock that evening as he was coming out of the Cambridge Arms. The disguise was very imperfect, since I had merely smeared the dye on my beard in the street, and the scar was made of sticking-plaster. It would not have borne a moment’s close inspection, but it was good enough for Copperdock, as I felt sure it would be. I escaped from him without difficulty, and, having taken a wet sponge with me, removed the scar and dye at the first opportunity and came quietly home. I beat Mr. Copperdock by about five minutes. + 

“As I had expected, he told Whyland the story of his adventure, and I was in a position to swear that he and I had been alone in the street. The result was to discredit his veracity still further. I then thought it time to act. You will remember that Copperdock said he found a numbered counter on his bed? That was the exact truth, although it seemed impossible, and nobody believed him. But it was capable of the simplest explanation in the world. Look here.” + 

The Black Sailor rose from his chair, and walked across to the bench, from which he picked up an apparatus made of wood and india rubber, not unlike a miniature crossbow. “I amused myself in my spare time by making this,” he said. “As you see, it has a holder which just takes a counter. You would be surprised to see how far and how accurately it will project it. I have frequently practised with it in the country, and I have attained sufficient skill in its use to be able to place a counter where I like at any range up to a hundred feet or so. + 

“Now, above my shop is a room, which I use for storage purposes. From the window of this room you can see into the window of Mr. Copperdock’s bedroom. I had merely to wait for a windless evening, fine enough for Mr. Copperdock to leave his window open, and seize my opportunity when I knew his house was empty. The opportunity came, and I took it. + 

“It might have been thought that by delivering the counter in advance I had increased my difficulties. But, on the contrary, I had diminished them. The obvious improbability of Mr. Copperdock’s story, that he had found a counter on his bed at a time when it was demonstrable that nobody had entered the house, was merely another link in the chain of suspicion which I was forging round him. I allowed a few days to pass, and then, the following Saturday, I took the final step. + 

“Now, even you, Dr. Priestley, failed to read the riddle of the broken hypodermic needle and the incrustation of potassium carbonate round the puncture. Yet it was ridiculously simple. I secured a piece of metallic potassium, and moulded it into the shape of a bullet to fit an airgun which I possessed. Into the head of this bullet I inserted the broken end of a hypodermic needle, which I had already charged with the same drug as had been so effectual in the case of Mr. Colburn. Keeping this prepared bullet in paraffin, to avoid oxidation, I placed the airgun ready upstairs, and waited for Mr. Copperdock’s return from the Cambridge Arms. He brought two friends home with him, and I was afraid at first that I should be compelled to postpone my attempt. It was essential to my scheme that he should be alone in the house when I fired the gun. + 

“However, the two friends left after a while, and Mr. Copperdock entered his bedroom and proceeded to undress. I could just see the washing-stand through a gap in his curtains, and I waited until he was bending over this. Then I loaded the gun with my potassium bullet, and pulled the trigger. I saw Mr. Copperdock spin round, and then he passed out of my line of vision. But I knew I had succeeded, and I came quietly down here. + 

“The bullet had possessed sufficient velocity to drive the needle well into Mr. Copperdock’s body, and I knew I could trust it to destroy its own evidence. I need scarcely explain the properties of metallic potassium to you, Dr. Priestley. On exposure to the air it oxidizes, as you know, first to the hydroxide, which is caustic potash, and then to the carbonate. The doctor who was called in quite correctly stated that the presence of the carbonate showed that caustic potash had been applied. But he never guessed that the caustic potash had itself been derived from potassium. + 

“I had expected that Ted Copperdock’s first act upon discovering his father’s body would be to call me. I thought that this would furnish me with an opportunity for adding yet another mystification for the police to solve. I placed a numbered counter on my own mantelpiece, and waited. Sure enough, young Copperdock came across to me. I met him in the shop, and we went over together, I taking care not to close the door behind us. I have no doubt that the scene in Mr. Copperdock’s room had been described to you in detail. But there is one incident which seems to have escaped everybody’s recollection. I was left alone in the room while Ted went for the doctor and Waters telephoned to Inspector Whyland. + 

“I had meant all along to contrive to be alone in the room sooner or later, and was prepared for the opportunity. I had in my pocket the handle of the paper-maker’s knife and one of the blades. I placed the handle in Mr. Copperdock’s right hand, and pressed the fingers round it. Then I put the blade and handle in the pocket of one of his overcoats, satisfied that sooner or later it would be found there, with his fingerprints upon it. A few minutes later, a chance remark of Inspector Whyland’s gave me a further idea. If the suicide theory were correct, the hypodermic syringe ought to be found. I had, I confess, overlooked this point, but it was readily rectified. Directly he left me, I looked out an old syringe, fitted the other half of the needle to it, and dropped it by the side of the road under Mr. Copperdock’s window. Waters found it within half an hour. + 

“Meanwhile, Inspector Whyland had returned here at my suggestion. He was the very witness I required to my finding of the counter. The door left open afforded an obvious suggestion of the means by which it had reached my mantelpiece. I did not care what theory he evolved as to the identity of the person who had entered the house. My only object was to confuse the issue as much as possible. + 

“Then, Dr. Priestley, Inspector Hanslet came upon the scene, and I knew that the real battle of wits had begun. As I have told you, I had spent years studying the characters of the members of the jury, and among them I had devoted a large part of my time to observing you. I soon discovered that Inspector Hanslet consulted you upon his principal cases, and I knew as soon as Hanslet appeared, that I was at last pitted against the most acute brain in England. I may say, without exaggeration, that the knowledge gave me the keenest pleasure which I had known for years.” + 

The Black Sailor paused, and smiled at his auditor benignly. “You see, Dr. Priestley,” he continued, “I was in rather a delicate position, where you were concerned. I had purposely left you until the last, because, as foreman of the jury, Dr. Morlandson wished you to have special treatment. You were to be warned, but your fate was to be left hanging over your head as long as possible. I was afraid that you would not attach much importance to the mere receipt of a counter. You are not the sort of person to be so easily frightened. Yet how to deliver a personal warning without giving you a clue which would be fatal to the execution of my design, I could not see. + 

“I knew Inspector Hanslet had discussed the Praed Street murders with you. Or rather, in deference to your well-known insistence upon exactitude, I will say that I believed it to be in the highest degree probable. During one of my evening walks, accompanied, I may say, by one of Inspector Whyland’s charming young men, I passed your house, and saw Inspector Hanslet enter it. It was rather more than a mere guess to infer that he, who had just taken charge of the case, was about to consult you upon it. + 

“Then, a day or two later, I saw in The Times the announcement of your hurried departure to Australia. Believe me, Dr. Priestley, I had a higher opinion of your courage than to imagine that you had hastened to seek a place of safety. I reasoned, and events proved that I reasoned correctly, that you alone had connected the names of the dead men with those who had served on the jury at Dr. Morlandson’s trial. You were therefore aware that your own life was threatened. But one thing puzzled you. If Dr. Morlandson were dead, how could the murders be accounted for? You would naturally wish to verify his death upon the spot, but you would endeavour to do so with the utmost secrecy. Hence, I thought, the announcement of your visit to Australia, which would mislead your antagonist, and account for your absence from London. The place in which to find you alone was obviously the Isle of Purbeck. + 

“So I suggested a scheme to Inspector Whyland, and here my chance thought of delivering a counter to myself came in useful. I was to go to Dorchester for the weekend⁠—I was thankful for the evidence I had already laid that the fatal period and place were the weekend and Praed Street⁠—and he was to remain here on the watch for the assassin who threatened me. It amused me to think that the solution of the whole mystery would lie under his very eyes, for the crossbow was on that bench, and the airgun stands in a rack in my bedroom. But, since I had invited him, I knew that he would attach no importance to these things, even if he noticed them. I left him in possession, and went to Dorchester. But from there I took a train to Wareham, and walked across the heath to Dr. Morlandson’s cottage, where I most artistically converted Mr. Ludgrove into the Black Sailor. + 

“You must remember that I lived on that heath for a year, during Dr. Morlandson’s lifetime. I have been there frequently since. There is a disused clay working not far from the cottage, and in this I had secreted a number of useful articles, among them a bicycle. With this I watched in the heather, feeling certain that you would not disappoint me. You did not, and our most interesting interview took place. + 

“After you had started for home, I made my preparations for departure. It was just possible that you would set the local police on my track, and I was taking no risks. I rolled a round and heavy stone over the path, which gave the sand a level and untrodden appearance, and effectually removed all traces of my bicycle. Then I walked to a spot on the shores of Newton Bay, where I knew that a punt, which is very rarely used, was drawn up. In this I rowed across through the backwaters to a point on the Wareham channel above Lake. I left the punt here, turned myself back again into Mr. Ludgrove, and in the morning walked to Hamworthy Junction, whence I caught a train to Dorchester. I was in plenty of time to dig my colchicum bulbs and return to London. + 

“Now, Dr. Priestley, I feel that I owe you some apology. Matters have turned out very differently from what I had expected, owing to circumstances over which I have no control. I had intended that you should survive for months, even perhaps years, in daily expectation of death leaping out at you from some unexpected corner. You are a determined man, but I think you will agree that even your iron will would have broken down at last under the strain. Every now and then, when you were most absorbed in your labours, a warning would reach you, a hint that the sands were running out, that you might not be allowed time even to finish the immediate task. I think in time you would have known something of the horror of despair which grips the innocent man condemned ruthlessly and without mercy, as you condemned Dr. Morlandson, Dr. Priestley.” + 

The Black Sailor’s voice had become harsh and menacing, and the Professor started from his chair to meet the attack which he anticipated. But the Black Sailor waved him back again with an imperious gesture. + 

“Sit down, Dr. Priestley!” he commanded. “I have not yet finished what I must say and you must hear. You need fear no violence, unless you attempt to escape from this room. But you are far too sensible to make any such attempt, which, as you see, would be futile. I could overpower you in an instant, and I should then be compelled to bind you hand and foot and gag you. A most humiliating situation for you, Dr. Priestley, and one uncomfortably reminiscent of the methods of the hangman, to whose care you delivered Dr. Morlandson, you remember.” + 

The Professor sank back into his chair. He realized that the Black Sailor was right, that in any struggle he must inevitably be overcome, and resistance would probably lead to his immediate death. If he were to leave this room alive, it must be by strategy rather than force. It was unthinkable that the Black Sailor would release him now that he had confessed the full details of his murderous campaign. He could only bide his time, seeking some means of extricating himself from this desperate situation. But what did the man mean by his assurance that he would employ no violence? + 

Meanwhile the Black Sailor had continued, in the deep, pleasant voice which had been one of the most striking attributes of Mr. Ludgrove. + 

“This is the vengeance which I had planned for you, Dr. Priestley. But, unfortunately, my plans have been thwarted. Long ago, when Dr. Morlandson was alive, he warned me that, well set up and healthy as I appeared to be, my heart was affected by organic disease. He told me frankly that it might be many years before it seriously affected my health, and that, with reasonable care, I might expect to attain the average term of years. But at the same time he warned me that my trouble might at any time become acute, and he described to me the symptoms which would be my signal to prepare for death. + 

“Those symptoms developed last week, Dr. Priestley, and I knew that I had only a short while longer to live. But I was determined not to die leaving the vengeance which had been bequeathed to me unaccomplished. I had sworn to be the instrument of justice upon those who had destroyed Dr. Morlandson’s life, for that life had been destroyed just as surely as though his original sentence had been carried out. And of those who had incurred the guilt, only you remained, Dr. Priestley. + 

“I could have shot you in your own house, and then turned the weapon upon myself. In any case I am to die very shortly, and I much prefer death at my own hands and under my own control to the anxious waiting for the uncertain hand of nature. It would have been the easiest way, perhaps, but it was not in accordance with the methods which I had so carefully developed. How much more fitting it would be that you should die in Praed Street, that your death should be the culminating point in the history of the murders in Praed Street! I believed that it could be done, and I set myself to work out the details. + 

“The police, as you are aware, have rather lost interest in you and me. The discovery of the knife in Mr. Copperdock’s coat pocket seems finally to have convinced them that the secret died with him, and, whatever the secret might have been, no further murders were to be anticipated. Detectives are busy people, they have no time to spare for academic research. I am sure that they are convinced that no actual danger menaces either Dr. Priestley or Mr. Ludgrove, although both of them are known to have received numbered counters. They were not likely to interfere with my schemes. + 

“You are aware of the steps which I took to bring you here. Had you refused to accompany me this evening, I should have shot you outright in your own study. But I knew that you would not refuse. The solution of the mystery had become a point of honour with you, and, besides, you had a message for me which I was sure that you would be glad of the opportunity to deliver. Surely you would not have hesitated to give the innocent Mr. Ludgrove the Black Sailor’s message, Dr. Priestley?” + 

The Professor forced a smile. “I had intended to do so, but⁠—he died, to use your own expression, before I had the opportunity.” + 

“Yes, that was unfortunate,” agreed the Black Sailor pleasantly. “But still, the fact that you had the message to deliver served its purpose. It was an added inducement to you to accept my invitation. And, by carefully emphasizing the possible danger which lurked in Praed Street, I worked upon your pride. You would not have refused to come with me, after that. And I told you the truth, I had revelations to make which I knew would interest you, and I think you have not been disappointed.” + 

He paused for a moment, and then continued, a sinister purpose in his voice: “And now the end has come. It is not the end I sought, but I welcome it as well as any other. We two will pass out of this world together, Dr. Priestley, you the last victim of my justice, and I the executioner. It is but anticipating my own death for a short time, and the means I shall employ will render even deeper the mystery which surrounds me. On Sunday morning the world will hear of two more strange deaths in Praed Street. I think your secretary will come round here before the night is over, and, being able to obtain no reply, will call in the police to his aid. How much of the riddle will they solve, I wonder?” + 

The Black Sailor stretched out his hand, and switched on a small electric hand-lamp which stood on a table by his side. “That will give us sufficient light for our purpose,” he said sombrely. Then, before the Professor could guess his intention, he suddenly leapt from his chair, turned out the gas which was burning at a bracket by the mantelpiece, and with a powerful wrench tore the bracket itself from the wall. It fell with a crash into the fireplace. + 

Then the Professor understood. He, too, leapt from his chair with a shout, and dashed blindly for the door. But the Black Sailor was there before him. “It is useless, Dr. Priestley,” he said menacingly. “The door is fastened securely, as is the window. The chimney is blocked, and there is no possible escape for us. I doubt if you would be heard if you call again for help, but I cannot risk it. Will you give me your word to wait quietly, or must I gag you and tie you up? Would you care to meet death bound like a criminal, Dr. Priestley?” + 

For a moment the two men stood face to face, the powerful form of the Black Sailor towering threateningly over the Professor. Behind them, with a faint hissing sound, the gas poured into the room through the broken bracket. Already the pungent smell of it caught Dr. Priestley by the throat. + 

And then, suddenly, the idea came to him. It was a forlorn, desperate hope, a scheme almost as dangerous as waiting supinely for the fatal vapours to overpower him. Yet⁠—it was worth trying. He nodded his head almost briskly. “I will not call for help,” he said, and, turning on his heel, he sat down again in the chair he had just quitted. + 

The Black Sailor followed his example, and so the two sat in silence, waiting, waiting. The atmosphere of the room grew thick and heavy, difficult to breathe. The Professor found his thoughts floating away to trifling things, he imagined himself a boy again, at school⁠—With a mighty effort of will he recalled them, forcing his mind to concentrate upon the thing he had to do. Yet, was it worth it? Death, in that comfortable chair, would be so easy. A pleasant languor crept over him. He had only to close his eyes and sleep⁠— + 

Again his will triumphed. He must wait a few seconds longer, wait till the whole room was full of gas. But could he, dare he? His senses were slipping away fast. Yet he must retain consciousness, if only for those few seconds. The Black Sailor was glaring at him with baleful eyes, eyes that suddenly seemed familiar, as though they stared out at him from the past, many, many years ago. Where had he seen those eyes before? + 

The Professor’s strength and energy were failing him fast. He knew that, even if the Black Sailor offered no opposition, he could not reach the broken pipe and stop the rush of the gas. He felt his muscles failing him, his brain refusing to struggle any longer against the luxurious sleep which enticed it. He must make his effort now, before he yielded to that sweet, enthralling sleep which could know no awakening. + 

Stealthily he felt in his pockets, forcing his reluctant fingers to their work. Then, even as the Black Sailor struggled to his feet, and stood there swaying dizzily, the Professor slid to the floor, and struck the match which he held in his hand. There was a roar as of the heavens opening, a bright, scorching sea of flame, and the Professor knew no more. + 

XXIII + 

The Will + 

He came to himself slowly and confusedly. A strong light was glaring into his eyes, and he could hear voices, voices which he did not recognize, all about him. He seemed to be lying on the floor, his shoulders supported in somebody’s arms. + 

Gradually he began to distinguish words and sentences. “This one’s coming round, I believe.” “All right, the doctor’ll be here in a minute.” “T’other one’s gone, I’m afraid. I can’t feel his pulse at all.” “Here, help me to clear this plaster off him, somebody. The explosion seems to have brought the ceiling down. It’s a wonder it didn’t blow the roof off. Have you got that gas turned off at the main yet?” “Ah, here’s the doctor. Been a bit of a smash here, doctor. Gas explosion, from what I can see of it. Two hurt, one of ’em killed, I fancy. Take this one first, will you?” + 

The Professor saw a face peering into his own. “Well, my friend, what’s happened to you? Blown up, eh? Let’s have a look at you. Any bones broken? Doesn’t look like it. Can you move your legs? Good. Any pain anywhere?” + 

“No. I was stunned, I think, when the explosion took place.” Dr. Priestley’s senses were returning rapidly. The whole scene flashed back to him, the feeble glimmer of the little hand-lamp, the figure of the Black Sailor, formidable, immense, swaying towards him⁠— + 

Before the supporting arms could prevent him, he had struggled to his feet. Something about his head felt unfamiliar, and he passed his hand over it. Every particle of hair had disappeared. He was bald, clean-shaven, without eyebrows or eyelashes. + 

“Steady, steady,” came a voice soothingly. “We’ll soon get you out of this. Here, sit down in this chair, or what remains of it.” + 

He let himself be guided to the chair. The outlines of the room, illuminated by the rays of two or three bulls-eye lanterns, began to be visible to him. He hardly recognized it. Everything it had contained was swept into inextricable confusion, as though a tornado had passed through it. Where the window had been was a square of dim grey light, the distant reflection of a street lamp. A whitish gritty dust covered everything, the debris of the fallen ceiling. And stretched out in front of the fireplace was the dim outline of a man’s figure, prone and motionless. + 

One of the men in the room came up to him. “Feeling better, eh? Narrow shave you’ve had, I should say. Do you remember who you are?” + 

“I am Dr. Priestley, of Westbourne Terrace,” replied the Professor. + 

The man gave a low whistle of incredulity. “Dr. Priestley? Well, you don’t look it.” + 

“I have letters in my pocket which will serve to identify me,” replied the Professor shortly. + 

He put his hand in his pocket and produced a packet of papers. The man took them, glanced through them and handed them back. “I beg your pardon, sir,” he said respectfully. “But⁠—I didn’t know you without your hair, and with your face blackened like that. Perhaps you could tell us who this is, sir?” + 

He flashed his lamp upon the features of the figure lying upon the floor. The Professor leant forward in his chair and gazed at them in silence. This man, too, was hairless as he was himself, as though he had been shaved by some expert barber. Beneath the grime which covered his face, beneath the lines which age and suffering had graven upon him, the Professor recognized the features which had graven themselves upon his memory so many years ago. He saw again the prisoner in the dock, the handsome clean-shaven face with its look of awful anxiety. And he knew where he had seen before those eyes which had stared into his before he had lost consciousness. + 

“That is Dr. Morlandson,” he replied gravely. + 

Dr. Priestley was removed to Westbourne Terrace, at his own urgent request, but it was a couple of days before his doctor would allow him to receive visitors. He was pretty badly shaken, and the poison which he had inhaled was having its usual after effects. But his brain was as active as ever, and he insisted that Hanslet, who had been waiting with what patience he could summon, should be admitted without further delay. + 

“Well, sir, you seem to have been right as usual,” he said. “But I don’t profess to begin to understand, although I have a document here which clears up a good many points. If you feel well enough, I should be very glad if you would tell me what happened in that room. I’ve arranged for the inquest on this Dr. Morlandson to be adjourned until you are well enough to attend. As a matter of fact, I don’t see how an inquest is going to be held at all. There’s been one already, on the same man, at Corfe Castle, years ago.” + 

The Professor told his story as simply as possible, outlining his actions and repeating the Black Sailor’s story, up to the moment when it had occurred to him that his only chance of escape was to produce an explosion. “It could not make things any worse, as far as I was concerned,” he said. “I was bound to be overcome by the gas in a very few minutes. But I had to wait until I judged the mixture of gas and air to be correct, and I was very doubtful whether this would take place before I became unconscious. I guessed that I should feel the force of the explosion least by lying on the floor, and, as it proved, that saved me. Morlandson, who was standing up when the explosion took place, bore the full brunt of it, and it killed him.” + 

“Well, it’s a most extraordinary case altogether,” replied Hanslet, as the Professor concluded his account. “This man Morlandson, or Ludgrove as we called him, displayed the most amazing ingenuity, and there was no reason why we should ever have suspected him, any more than we suspected anybody else in the neighbourhood. And the way he gradually concentrated our attention on poor Copperdock was masterly. + 

“No doubt you will like to hear our side of the story. It’s fairly simple. About ten minutes before midnight the constable on duty outside Ludgrove’s shop heard a terrific crash and a noise of breaking glass. He hammered at the door, and, getting no reply, had the sense to make his way round to the back, eventually reaching the place by much the same route as the Black Sailor used, according to what you have just told me. He found the window blown out of the back room, a terrible mess inside, and a jet of burning gas coming out of the broken bracket. He blew his whistle, and by the time that two or three of our fellows had got inside, you came to, Professor. + 

“Of course, when I heard that you had identified the dead man as Dr. Morlandson, I thought you were still dizzy with the shock. We couldn’t make out who he was; he was dressed as a sailor, but we couldn’t recognize his face, black and with all the hair burnt off. It couldn’t be Ludgrove, yet, if it wasn’t, what had become of the old herbalist? + 

“We next set to work to search the house. The first thing we found, lying on the dressing table, was a most interesting document, which I should like you to read, Professor. It was in a sealed envelope, addressed ‘To all whom it may concern.’ ” + 

Hanslet produced a sheet of paper, covered with writing which the Professor recognized as being the same as that of the letter which Ludgrove had sent him. He beckoned to Harold, who had been listening from the further end of the room. “Read that to me, my boy,” he said. + 

Harold took the paper and opened it. It contained no heading, but started abruptly. + 

I, known now as Elmer Ludgrove, and practising as a herbalist in Praed Street, am in reality Ernest Morlandson, late a Doctor of Medicine, found guilty in the year 1906 of murdering Lord Whatley by the administration of an overdose of morphia. This statement can be verified by an examination of my fingerprints, and by a comparison of certain marks upon my body with Dr. Morlandson’s record, in the possession of the prison authorities. + 

I was found guilty, by a jury of men incapable of appreciating my motives, of wilful murder. My defence is that put forward at the time of my trial, that I believe, and do still believe, that my action was one of mercy rather than crime. As to the motives imputed to me, I affirm that, until shortly before my trial, I had no knowledge that my name had any place in Lord Whatley’s will. + 

I have spent fourteen years in a convict prison, and have seen all that I loved and honoured languish and die, my beloved wife, my professional status, my good name. I have descended to the uttermost depths, I have drunk the cup of bitterness of its dregs. The iron has entered into my soul. I was condemned to death for an act of mercy; I have lived for an act of justice. + 

Justice has no quarrel with those who prosecuted me. They did their duty. Nor is her sword pointed against the judge who sentenced me, or the prison authorities who held me in durance. They too but did their duty. It is upon those who condemned me, who, ignorant and careless, disregarded justice as a thing of no account, that the sword of justice has been turned. I have been her swordbearer. + 

Prison has been to me a hard and bitter school, a grinding university of crime. Here I have learnt the thousand devices by which men deceive their neighbours, the change of appearance, of voice, of character; the discarding of one personality and the assumption of another. I left prison fully prepared to execute the design which I had formed during the long horror of seclusion. + 

As Dr. Morlandson, I lived in seclusion upon my release. My plans were made; I had leisure and means in which to carry them out. Dr. Morlandson must die, and another must take his place. I sold most of my former possessions, and carried to my retreat only the few things I still required. Among these was a skeleton, which I had acquired many years before. I built my laboratory, and filled it with highly combustible substances. And meanwhile I experimented with new and hitherto unheard-of drugs. + 

When I was ready, I staged my own death. I entered my laboratory, locked the door on the inside, and arranged the skeleton in such a way that it would become a mere charred collection of bones, but would not be utterly consumed. With it I placed all the incombustible means of identification that I could find, chief among them a gold ring. Then, having lit a fuse, and placed my combustibles round it, I made my escape by a ladder through the skylights of the laboratory. I should add that I had collected a quantity of meat from the butcher and placed it where the fire would reach it. The smell of burning flesh was a useful element of suggestion. + 

My plan succeeded. Dr. Morlandson died and was buried. I retired to a hiding-place which I had prepared and provisioned, a disused clay-working 846 yards South 23 degrees East (true) from my laboratory. My hair had turned white during my imprisonment. I had only to allow my beard to grow, and I became the venerable herbalist, Elmer Ludgrove, seeking premises in which to practise his trade. + 

By the time that the contents of this letter become public, the justice of which I shall have been the instrument will be accomplished. This is my last will and testament, given before my appearance at the Court of the Eternal Judge, Who has greater mercy than any earthly jury. The remains of my fortune are contained, in the form of Bank of England notes to the value of fifteen thousand pounds, in a tin box deposited in the clay-workings whose position I have already indicated. + 

I have wielded unsparingly the sword of justice. But true justice makes amends to the innocent at the same time as it punishes the guilty. I therefore bequeath all my possessions to the relatives of those who have fallen by my hand, to be apportioned in such shares as the Public Trustee, whom I hereby appoint as my trustee, shall decide. + 

“The work of a madman,” commented Hanslet, as Harold finished his reading. + 

“A madman? I wonder,” replied the Professor slowly. “If a man who gets a fixed idea into his head, and pursues it through every difficulty, is a madman, then I agree. But in that case some of the greatest names in history must be convicted of madness. I believe that Morlandson really believed that he was executing justice. Perhaps he was. Is that document valid, Inspector?” + 

“I suppose so,” replied Hanslet. “It is signed, and witnessed. The signature is ‘Ernest Morlandson,’ and below that ‘Elmer Ludgrove.’ The witnesses’ signatures are opposite the latter, and the paper has been folded, so that the witnesses could see nothing but the Ludgrove signature.” + 

“And who are the witnesses?” asked the Professor. + 

Hanslet smiled. “One of them is Elizabeth Cooper, his charwoman. The other is Samuel Copperdock; the document is dated a week before that unfortunate man’s death. I think you will agree that this last touch was typical of the methods of the Black Sailor.” + 

A few weeks later, when the Professor had sufficiently recovered to resume his normal occupations, Mary the parlourmaid announced to him that a lady and gentleman wished to see him on business. + 

They proved to be Ted and Ivy, very shy, and apparently wholly unable to express the object of their visit. At last, by strenuous efforts, the Professor and Harold between them got Ted to the point. + 

“It’s like this, sir,” he said. “You know all about that will of Mr. Lud⁠—, Dr. Morlandson’s, I should say, sir.” + 

“Yes, I know all about it,” replied the Professor. “I must congratulate you upon receiving some compensation at least for that man’s crimes.” + 

“I’m sure it’s very good of you, sir,” said Ted, obviously ill at ease. “We were wondering⁠—that is, Miss Tovey and myself, sir, seeing that we’re not so to speak familiar with these lawyer folk⁠—if you’d be so good as to help us, sir.” + 

“Help you? Of course I will help you to the best of my ability,” replied the Professor heartily. “What is it that you want me to do for you?” + 

The direct question was too much for Ted, who flushed scarlet and stammered feebly. It was Ivy who stepped into the breach. + 

“We want to arrange that our shares should be put together in one lump, Dr. Priestley,” she said. “We don’t either of us quite know how to ask about it. I think it could be managed, don’t you?” + 

The Professor’s eyes twinkled. “I feel sure it could,” he replied. “That is, of course, if there were a sufficiently good reason for such a procedure.” + 

Ivy suddenly became intensely interested in the pattern of the carpet. “There is a⁠—a very good reason,” she said, in a voice hardly above a whisper. + 

The Professor glanced from one to the other and smiled with the smile of an old man who has not yet lost his sympathy with the dreams of youth. + 

“Will you tell me the reason, Miss Tovey?” he asked. + 

“We’re going to get married,” replied Ivy, blushing prettily. + 