Chapter 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 cross-bow. “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 air-gun 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 air-gun 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 finger-prints 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 inThe Timesthe 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 week-end—I was thankful for the evidence I had already laid that the fatal period and place were the week-end 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 cross-bow was on that bench, and the air-gun 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 fire-place.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.
“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 cross-bow. “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 air-gun 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 air-gun 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 finger-prints 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 inThe Timesthe 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 week-end—I was thankful for the evidence I had already laid that the fatal period and place were the week-end 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 cross-bow was on that bench, and the air-gun 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 fire-place.
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.