CHAPTER III. The Case of Mr. Foggart Almost the only dogmatism that Martin Hewitt permitted himself in regard to his professional methods was one on the matter of accumulative probabilities. Often, when I have remarked upon the apparently trivial nature of the clues by which he allowed himself to be guided, sometimes to all seeming in the very face of all likelihood, he has replied that two trivialities pointing in the same direction became at once by their mere agreement, no trivialities at all but enormously important considerations. If I were in search of a man, he would say, of whom I knew nothing but that he squinted, bore a birthmark on his right hand, and limped, and I observed a man who answered to the first peculiarity, so far the clue would be trivial because thousands of men squint. Now if that man presently moved and exhibited a birthmark on his right hand, the value of that squint and that mark would increase at once a hundred or a thousandfold, apart their little, together much. The weight of evidence is not doubled merely, it would be only doubled if half the men who squinted had right hand birthmarks, whereas the proportion, if it could be ascertained, would be perhaps more like one in ten thousand. The two trivialities pointing in the same direction become very strong evidence, and when the man is seen to walk with a limp, that limp, another triviality, reinforcing the others, brings the matter to the rank of a practical certainty. The Bertillon system of identification, what is it, but a summary of trivialities. Thousands of men are of the same height, thousands of the same length of foot, thousands of the same girth of head, thousands correspond in any separate measurement you may name. It is when the measurements are taken together that you have your man identified forever. Just consider how few, if any, of your friends correspond exactly in any two personal peculiarities. Hewitt's dogma received its illustration unexpectedly close at home. The old house wherein my chambers and Hewitt's office were situated contained, besides my own, two or three more bachelor's dens, in addition to the offices on the ground and first and second floors.  It was only after a long residence, by an accidental remark of the housekeepers, that I learned the man's name, which was not painted on his door, or displayed, with all the others, on the wall of the ground floor porch. Mr. Foggott appeared to have few friends, but lived in something as nearly approaching luxury as an old bachelor living in chambers can live. An ascending case of champagne was a common phenomenon of the staircase, and I have more than once seen a picture, destined for the top floor, of a sort that went far to awaken green covetousness in the heart of a poor journalist. The man himself was not altogether pre-possessing.  On the whole his appearance was rather vulgar, rather arrogant, and rather suspicious, without any very pronounced quality of any sort. But certainly he was not pretty. In the end, however, he was found shot dead in his sitting-room. It was in this way. Hewitt and I had dined together at my club, and late in the evening had returned to my rooms to smoke and discuss whatever came uppermost. I had made a bargain that day with two speculative odd-lots at a book sale, each of which contained a hidden prize. We sat talking and turning over these books while time went unperceived, when suddenly we were startled by a loud report. Clearly it was in the building. We listened for a moment, but heard nothing else. And then he would express his opinion that the report was that of a gunshot. Gunshots in residential chambers are not common things, therefore I got up and went to the landing, looking up the stairs and down. At the top of the next flight I saw Mrs. Clayton, the housekeeper. She appeared to be frightened and told me that the report came from Mr. Fogget's room. She thought he might have had an accident with the pistol that usually lay on his mantelpiece. We went upstairs with her, and she knocked at Mr. Fogget's door. There was no reply. Through the ventilating fan over the door it could be seen that there were lights within. A sign, Mrs. Clayton maintained, that Mr. Fogget was not out. We knocked again, much more loudly, and called, but still ineffectually. The door was locked, and an application of the housekeeper's key proved that the tenant's key had been left in the lock inside. Mrs. Clayton's conviction that something had happened became distressing. And in the end Hewitt pried open the door with a small poker. Something had happened.  The head was ill to look at, and by it lay a large revolver of the full-sized army pattern. Mrs. Clayton ran back toward the landing with faint screams. Run, Brett, said Hewitt, a doctor, and a policeman. I bounced down the stairs half a flight at a time. First I thought a doctor. He may not be dead. I could think of no doctor in the immediate neighborhood, but ran up the street away from the strand as being the more likely direction for the doctor, although less so for the policeman. It took me a good five minutes to find the medico, after being led astray by a red lamp at a private hotel, and another five to get back with a policeman. Fogget was dead, without a doubt. Probably had shot himself, the doctor thought, from the powder blackening and other circumstances. Certainly nobody could have left the room by the door, or he must have passed my landing, while the fact of the door being found locked from the inside made the thing impossible. There were two windows to the room, both of which were shut, one being fastened by the catch, while the catch of the other was broken, an old fracture. Below these windows was a sheer drop of fifty feet or more without a foot or hand-hold near. The windows in the other rooms were shut and fastened. Certainly it seemed suicide, unless it were one of those accidents that will occur to people who fiddle ignorantly with firearms. Soon the rooms were in possession of the police, and we were turned out. We looked in at the housekeeper's kitchen, where her daughter was reviving and calming Mrs. Clayton with gin and water. You mustn't upset yourself, Mrs. Clayton, he would say, or what will become of us all. The doctor thinks it was an accident. He took a small bottle of sewing machine oil from his pocket and handed it to the daughter, thanking her for the loan. There was little evidence at the inquest. The shot had been heard, the body had been found, that was the practical sum of the matter. No friends or relatives of the dead man came forward. The doctor gave his opinion as to the probability of suicide or an accident, and the police evidence tended in the same direction. Nothing had been found to indicate that any other person had been near the dead man's rooms on the night of the fatality. On the other hand, his papers, bank book, etc. proved him to be a man of considerable substance with no apparent motive for suicide. The police had been unable to trace any relatives, or indeed any nearer connections than casual acquaintances, fellow clubmen, and so on. The jury found that Mr. Foggett had died by accident. Well, Brett, he would ask me afterward, what do you think of the verdict? I said that it seemed to me the most reasonable one possible, and to square with the common sense view of the case. Yes, he replied, perhaps it does. From the point of view of the jury and on their information, their verdict was quite reasonable. Nevertheless, Mr. Foggett did not shoot himself. He was shot by a rather tall, active, young man, perhaps a sailor, but certainly a gymnast, a young man whom I think I could identify if I saw him. But how do you know this? By the simplest possible of inferences, which you may easily guess if you will but think. But then why didn't you say this at the inquest? My dear fellow, they don't want any inferences and conjectures at an inquest. They only want evidence. If I had traced the murderer, of course, then I should have communicated with the police. As a matter of fact, it is quite possible that the police have observed and know as much as I do or more.  But if you are right, how did the man get away? Come, we are near home now. Let us take a look at the back of the house. He couldn't have left by Foggett's landing door, as we know, and as he was there, I am certain of that, and as the chimney is out of the question, for there was a good fire in the grate, he must have gone out by the window. Only one window is possible, that with the broken catch, for all the others were fastened inside. Out of that window then he went. But how? The window is fifty feet up. Of course it is. But why will you persist in assuming that the only way of escape by a window is downward? See now, look up there. The window is at the top floor, and it has a very broad sill. Over the window is nothing but the flat face of the gable end, but to the right and a foot or two above the level of the top of the window an iron gutter ends. Observe, it is not of lead composition but a strong iron gutter supported just at its end by an iron bracket. If a tall man stood on the end of the window sill, steadying himself by the left hand and leaning to the right, he could just touch the end of this gutter with his right hand. The full stretch, toe to finger, is seven feet three inches. I have measured it. An active gymnast or a sailor could catch the gutter with a slight spring and by it draw himself upon the roof. You will say he would have to be very active, dexterous and cool. So he would. And that very fact helps us because it narrows the field of inquiry. We know the sort of man to look for because being certain as I am that the man was in the room, I know that he left in the way I am telling you. He must have left in some way and all the other ways being impossible. This alone remains difficult as the feet may seem. The fact of his shutting the window behind him further proves his coolness and address at so great a height from the ground. All this was very plain, but the main point was still dark. You say you know that another man was in the room. I said, how do you know that? As I said, by an obvious inference, come now, you shall guess how I arrived at the inference. You often speak of your interest in my work and the attention with which you follow it. This shall be a simple exercise for you. You saw everything in the room as plainly as I myself. Bring the scene back to your memory and think over the various small objects littering about and how they would affect the case. Quick observation is the first essential for my work. Did you see a newspaper, for instance? Yes, there was an evening paper on the floor, but I didn't examine it. Anything else? On the table, there was a whiskey decanter taken from the tantalist stand on the sideboard and one glass. That by the by, I added, looked as though only one person were present. So it did, perhaps, although the inference wouldn't be very strong. Go on.  There was, of course, all the ordinary furniture, but no chair pulled up to the table except that used by Fogget himself. That's all I noticed, I think. Stay. There was an astray on the table and a partly burned cigar near it. Only one cigar, though. Excellent. Excellent indeed. As far as memory and simple observation go, you saw everything plainly and you remember everything. Surely now you know how I found out that another man had just left? No, I don't. Unless there were different kinds of ash in the astray. That is a fairly good suggestion, but there were not. There was only a single ash corresponding in every way to that on the cigar. Don't you remember everything that I did as we went downstairs? You returned a bottle of oil to the housekeeper's daughter, I think. I did. Doesn't that give you a hint? Come. You surely have it now. I haven't. Then I shan't tell you. You don't deserve it. Think and don't mention the subject again till you have at least one guest to make. The thing stares you in the face. You see it, you remember it, and yet you won't see it. I won't encourage your slovenliness of thought, my boy, by telling you what you can know for yourself if you like. Goodbye. I'm off now. There's a case in hand I can't neglect. Don't you propose to go further into this, then? Hewitt shrugged his shoulders. I'm not a policeman, he said. The case is in very good hands. Of course, if anybody comes to me to do it as a matter of business, I'll take it up. It's very interesting. But I can't neglect my regular work for it. Naturally I shall keep my eyes open and my memory in order. Sometimes these things come into their hands by themselves, as it were. In that case, of course, I am a loyal citizen and ready to help the law. Au revoir. I am a busy man myself and thought little more of Hewitt's conundrum for some time. Indeed, when I did to think, I saw no way to the answer. A week after the inquest, I took a holiday. I had written my nightly leaders regularly every day for the past five years, and saw no more of Hewitt for six weeks. After my return, with still a few days of leave to run, one evening we together turned into Lutzatti's off Coventry Street for dinner. I have been here several times lately, Hewitt said. They feed you very well. No, not that table. He seized my arm as I turned to an unoccupied corner. I fancy its draughty. He led the way to a longer table, where a dark, live, and, as well as could be seen, tall young man already sat, and took chairs opposite him. We had scarcely seated ourselves before Hewitt broke into a torrent of conversation on the subject of bicycling. As our previous conversation had been of a literary sort, and as I had never known Hewitt at any other time to show the slightest interest in bicycling, this rather surprised me. I had, however, such a general outsider's grasp of the subject, as is usual in a journalist of all work, and managed to keep the talk going from my side. As we went on I could see the face of the young man opposite, brightened with interest. He was a rather fine-looking fellow, with a dark, though very clear skin, but had a hard, angry look of eye, a prominence of cheekbone and a squareness of jaw that gave him a rather uninviting aspect. As Hewitt rattled on, however, our neighbor's expression became one of pleasant interest merely. Of course, Hewitt said, we've a number of very capital men just now, but I believe a deal in the forgotten writers of five, ten, and fifteen years back, Osmond, I believe, was better than any man writing now, and I think it would puzzle some of them to be turnable, as he was, at his best. But poor old Cortis, really, I believe he was as good as anybody. Nobody ever beat Cortis, except let me see. I think somebody beat Cortis once, was it now? I can't remember. Lyle's, said the young man opposite, looking up quickly. Ah, yes, Lyle's it was. Charlie Lyle's. Wasn't it a championship? Mile championship, 1880. Cortis won the other three, though. Yes, so he did. I saw Cortis when he first broke the old 246 mile record. And straightway, Hewitt plunged into a whirl of talk of bicycles, tricycles, records, racing cyclists, Hillier and Sniner and Noel Whiting, Taylorson and Appleyard, talk wherein the young man opposite wore an animated chair while I was left in the cold. Our new friend, it seems, had himself been a prominent racing bicyclist a few years back, and was presently at Hewitt's request, exhibiting a neat gold medal that hung at his watchguard. That was one he explained in the old tall bicycle days, the days of bad tracks, when every racing cyclist carried cinder scars on his face from numerous accidents. He pointed to a blue mark on his forehead, which he told us was a track scar, and described a bad fall that had cost him two teeth and broken others. The gaps among his teeth were plain to see as he smiled. Presently the waiter brought dessert, and the young man opposite took an apple. Nutcrackers and a fruit knife lay on our side of the stand, and Hewitt turned the stand to offer him the knife. No thanks, he said. I only polish a good apple, never peel it. It's a mistake, except with thick-skinned foreign ones. And he began to munch the apple as only a boy or a healthy athlete can. Presently he turned his head to order coffee. The waiter's back was turned, and he had to be called twice. To my unutterable amazement Hewitt reached swiftly across the table, snatched the half-eaten apple from the young man's plate, and pocketed it, gazing immediately with an abstracted air, had a painted cupid on the ceiling. Our neighbor turned again, looked doubtfully at his plate and the tablecloth about it, and then shot a keen glance in the direction of Hewitt. He said nothing, however, but took his coffee and his bill to liberately drank the former, gazing quietly at Hewitt as he did it, paid the latter, and left. Immediately Hewitt was on his feet and, taking an umbrella which stood near, followed. Just as he reached the door he met our late neighbor who had turned suddenly back. Your umbrella, I think, Hewitt asked, offering it. Yes, thanks. But the man's eye had more than its former hardness, and his jaw muscles tightened as I looked. He turned and went. Hewitt came back to me. Pay the bill, he said, and go back to your rooms. I will come on later. I must follow this man. It's the Foggett case. As he went out I heard a cab rattle away, and immediately after it, another. I paid the bill and went home. It was ten o'clock before Hewitt turned up, calling at his office below, on his way up to me. Mr. Sidney Mason, he said, is the gentleman the police will be wanting to-morrow. I expect for the Foggett murder. He is as smart a man as I remember ever meeting, and has done me rather neatly twice this evening. You mean the man we sat opposite, at Lutzatis, of course? Yes. I got his name, of course, from the reverse of that gold medal he was good enough to show me. But I fear he has built me over the address. He suspected me, that was plain, and left his umbrella by way of experiment, to see if I were watching him sharply enough to notice the circumstance, and to avail myself of it to follow him. I was hasty and fell into the trap. He cabbed it away from Lutzatis, and I cabbed it after him. He has led me a pretty dance up and down London tonight, and two cabbies made quite a stroke of business out of us. In the end he entered a house, of which, of course, I have taken the address, but I expect he doesn't live there. He is too smart a man to lead me to his den. But the police can certainly find something of him at the house he went in at, and I expect left by the back way. By the way, you never guessed the simple little puzzle as to how I found that this was a murder, did you? Do you see it now, of course? Something to do with that apple you stole, I suppose? Something to do with it, and I should think so! You were the innocent. Just ring your bell, we'll borrow Mrs. Clayton's sewing machine oil again. On the night we broke into Foggett's room you saw the nut shells and the bitten remains of an apple on the sideboard, and you remembered it, and yet you couldn't see that in that piece of apple, possibly, lay an important piece of evidence. Of course, I never expected you to have arrived at any conclusion, as I had, because I had ten minutes in which to examine that apple and to do what I did with it, but at least you should have seen the possibility of evidence in it. First now the apple was white. A bitten apple, as you must have observed, turns a reddish-brown color if left to stand long. Different kinds of apples brown with different rapidities, and the browning always begins at the core. This is one of the twenty thousand tiny things that few people take the trouble to notice, but which it is useful for a man in my position to know. A russet will brown quite quickly. The apple on the sideboard was, as near as I could tell, a New Town Pippin, or other apple of that kind, which will brown at the core, in from twenty minutes to half an hour, and in other parts in a quarter of an hour or more. When we saw it, it was white, with barely a tinge of brown about the exposed core. Inference, somebody had been eating it fifteen or twenty minutes before, perhaps a little longer, and inference supported by the fact that it was only partly eaten. I examined that apple and found it bore marks of very irregular teeth. While you were gone, I oiled it over, and rushing down to my rooms, where I always have a little plaster of Paris handy for such work, took a mold of the part where the teeth had left the clearest marks. I then returned the apple to its place for the police to use if they thought fit. Looking at my mold, it was plain that the person who had bitten that apple had lost two teeth, one at the top and one below, not exactly opposite, but nearly so. The other teeth, although they would appear to have been fairly sound, were irregular in size and line. Now the dead man had, as I saw, a very excellent set of false teeth, regular and sharp, with none missing. Therefore it was plain that somebody else had been eating that apple. Do I make myself clear? Quite, go on. There were other inferences to be made, slighter, but all pointing the same way. For instance, a man of Foggett's age does not, as a rule, munch an unpeeled apple like a schoolboy. In France, a young man and healthy. Why I came to the conclusion that he was tall, active, a gymnast, and perhaps a sailor, I have already told you when we examined the outside of Foggett's window. It was also pretty clear that robbery was not the motive, since nothing was disturbed, and that a friendly conversation had preceded the murder, witnessed the drinking and the eating of the apple. Whether or not the police notice these things, I can't say. If they had had their best men on, they certainly would, I think, but the case to a rough observer looked so clearly one of accident or suicide that possibly they didn't. As I said, after the inquest I was unable to devote any immediate time to the case, but I resolved to keep my eyes open. The man to look for was tall, young, strong, and active, with a very irregular set of teeth, a tooth missing from the lower jaw just to the left of the center, and another from the upper jaw, a little farther still toward the left. He might possibly be a person I had seen about the premises. I have a good memory for faces, or of course, he possibly might not. Just before you returned from your holiday, I noticed a young man at Utsatis, whom I remembered to have seen somewhere about the offices in this building. He was tall, young, and so on, but I had a client with me and was unable to examine him more narrowly. Indeed, as I was not exactly engaged on the case, and as there are several tall young men about, I took little trouble. But today, finding the same young man with a vacant seat opposite him, I took the opportunity of making a closer acquaintance. You certainly managed to draw him out. Oh, yes, the easiest person in the world to draw out is a cyclist. The easiest cyclist to draw out is, of course, the novice, but the next easiest is the veteran. When you see a healthy, well-trained looking man who nevertheless has a slight stoop in his shoulders, and maybe a medal on his watchguard, it is always safe to try him first with a little cycle-racing talk. I soon brought Mr. Mason out of his shell, read his name on the medal, and had a chance of observing his teeth. Indeed, he spoke of them himself. Now, as I observed just now, there are several tall, athletic young men about, and also there are several men who have lost teeth. But now I saw this tall and athletic young man had lost exactly two teeth, one from the lower jaw just to the left of the center and another from the upper jaw farther still toward the left. Trivialities, pointing in the same direction, become important considerations. More, his teeth were irregular throughout, and as nearly as I could remember it, looked remarkably like this little plaster mold of mine. He produced from his pocket an irregular lump of plaster about three inches long. On one side of this appeared in relief the likeness of two irregular rows of six or eight teeth, minus one in each row, where a deep gap was seen in the position spoken of by my friend. He proceeded. This was enough, at least to set me after this young man. But he gave me the greatest chance of all when he turned and left his apple, eaten, unpeeled, remember, another important triviality, on his plate. I'm afraid I wasn't at all polite, and I ran the risk of arousing his suspicions, but I couldn't resist the temptation to steal it. I did, as you saw, and here it is. He brought the apple from his coat pocket. One bitten side, placed against the upper half of the mold, fitted precisely, a projection of apple filling exactly the deep gap. The other side, similarly, fitted the lower half. There's no getting behind that, you see, he remarked, merely observing the man's teeth was a guide to some extent. But this is as plain as his signature, or his thumb impression. You'll never find two men bite exactly alike, no matter whether they leave distinct teeth marks or not. Here, by the by, is Mrs. Clayton's oil. We'll take another mold from this apple and compare them. He oiled the apple, heaped a little plaster in a newspaper, took my water junk, and rapidly pulled off a hard mold. The parts corresponding to the merely broken places in the apple were, of course, dissimilar. But as to the teeth marks, the impressions were identical. That will do, I think, here it said. Tomorrow morning, Brett, I shall put up these things in a small parcel and take them round to Bow Street. But are they sufficient evidence? Quite sufficient for the police purpose. There is the man and all the rest, his movements on the day and so forth are simply matters of inquiry, at any rate, that is, police business. I had scarcely sat down to my breakfast on the following morning, when Hewitt came into the room and put a long letter before me. From our friend of last night, he said, read it. This letter began abruptly and undated and was as follows. To Martin Hewitt, Esquire. Sir, I must compliment you on the droidness you exhibited this evening in extracting from me my name. The address I was able to balk you of for the time being, although by the time you read this, you will probably have found it through the law list, as I am an admitted solicitor. That, however, will be of little use to you, for I am removing myself, I think, beyond the reach even of your abilities of search. I knew you well by sight, and was perhaps foolish to allow myself to be drawn as I did. Still, I had no idea that it would be dangerous, especially after seeing you as a witness with very little to say at the inquest upon the scoundrel I shot. You are somewhat discourteous seizure of my apple at first amazed me. Indeed, I was a little doubtful as to whether you had really taken it. But it was my first warning that you might be playing a deep game against me, incomprehensible as the action was to my mind. I subsequently reflected that I had been eating an apple instead of taking the drink he first offered me in the dead wretches' rooms on the night he came to his merited end. From this I assumed that your design was in some way to compare what remained of the two apples, although I do not presume to fathom the depths of your detective system. Still, I have heard of many of your cases, and profoundly admire the keenness you exhibit. I am thought to be a keen man myself, but although I was able, to some extent, to hold my own tonight, I admit that your acumen in this case alone is something beyond me. I do not know by whom you are commissioned to hunt me, nor to what extent you may be acquainted with my connection with the creature I killed. I have sufficient respect for you, however, to wish that you should not regard me as a vicious criminal, and a couple of hours to spare in which to offer you an explanation that will convince you that such is not altogether the case. A hasty and violent temper I admit possessing. But even now I cannot forget the one crime it has led me into, for it is, I suppose, strictly speaking, a crime.  It was he who murdered my mother, and nonetheless murdered her because she died of a broken heart. That he was also a thief and a hypocrite might have concerned me little, but for that. Of my father I remember very little. He must, I fear, have been a weak and incapable man in many respects. He had no business abilities, in fact, was quite unable to understand the complicated business matters in which he largely dealt. Foggot was a consummate master of all those arts of financial jugglery that make so many fortunes and ruin so many others in matters of company promoting stocks and shares. He was unable to exercise them, however, because of a great financial disaster in which he had been mixed up a few years before, and which made his name want to be avoided in future. In these circumstances he made a sort of secret and informal partnership with my father, who, ostensibly alone in the business, acted throughout on the directions of Foggot, understanding as little what he did, poor simple man, as a schoolboy would have done. The transactions carried on went from small to large, and unhappily from honorable to dishonorable. My father relied on the superior abilities of Mr. Foggot with an absolute trust, carrying out each day the directions given him privately the previous evening, buying, selling, printing, prospectuses, signing whatever had to be signed, all with the sole responsibility and as sole partner, while Foggot, behind the scenes, absorbed the larger share of the profits. In brief my unhappy and foolish father was a mere tool in the hands of the cunning scoundrel who pulled all the wires of the business, himself unseen and irresponsible. At last three companies, for the promotion of which my father was responsible, came to grief in a heap. Fraud was written large over all their history, and while Foggot retired with his plunder, my father was left to meet ruin, disgrace, and imprisonment. From beginning to end, he and only he was responsible. There was no shred of evidence to connect Foggot with the matter, and no means of escape from the net drawn about my father.  Of this I knew nothing at the time, again and again as a small boy I remember asking of my mother why I had no father at home as other boys had, unconscious of the stab I thus inflicted on her gentle heart. Of her my earliest as well as my latest memory is that of a pale weeping woman who grudged to let me out of her sight. Little by little I learned the whole cause of my mother's grief, for she had no other confidant, and I fear my character developed early for my first coherent remembrance of the matter is that of a childish design to take a table knife and kill the bad man who had made my father die in prison and caused my mother to cry. One thing, however, I never knew the name of that bad man. Again and again as I grew older I demanded to know, but my mother always withheld it from me, with a gentle reminder that vengeance was for a greater hand than mine. I was seventeen years of age when my mother died. I believed that nothing but her strong attachment to myself and her desire to see me safely started in life kept her alive so long. Then I found that through all those years of narrowed means she had contrived to scrape and save a little money, sufficient as it afterward proved to see me through the examinations for entrance to my profession with the generous assistance of my father's old legal advisers, who gave me my articles and who have all along treated me with extreme kindness. Most of the succeeding years of my life do not concern the matter in hand. I was a lawyer's clerk in my benefactor's service and afterward a qualified man among their assistants. All through the firm were careful in pursuance of my poor mother's wishes that I should not learn the name or whereabouts of the man who had wrecked her life and my father's. I first met the man himself at the Clifton Club, where I had gone with an acquaintance who was a member. It was not till afterward that I understood his curious awkwardness on that occasion. A week later I called, as I had frequently done, at the building in which your office is situated, on business with a solicitor who has an office on the floor above your own. On the stairs I almost ran against Mr. Foggart. He started and turned pale, exhibiting signs of alarm that I could not understand, and asked me if I wished to see him. No, I replied. I didn't know you lived here. I am after somebody else just now. Aren't you well? He looked at me rather doubtfully and said he was not very well. I met him twice or thrice after that, and on each occasion his manner grew more friendly in a servile, flattering and mean sort of way. A thing unpleasant enough in anybody, but doubly so in the intercourse of a man with another young enough to be his own son. Still, of course, I treated the man civilly enough. On one occasion he asked me into his rooms to look at a rather fine picture he had lately bought, and observed casually, lifting a large revolver from the mantelpiece, you see I am prepared for any unwelcome visitors to my little den, he-he. Conceiving him, of course, to refer to burglars, I could not help wondering at the forced and hollow character of his laugh. As he went down the stairs, he said, I think we know one another pretty well now, Mr. Mason, eh? And if I could do anything to advance your professional prospects, I should be glad of the chance, of course. I understand the struggles of a young professional man, he-he. It was the forced laugh again, and the man spoke nervously. I think, he added, that if you will drop in tomorrow evening, perhaps I may have a little proposal to make, will you? I assented, wondering what his proposal could be. Perhaps this eccentric old gentleman was a good fellow after all, anxious to do me a good turn, and his awkwardness was nothing but a natural delicacy in breaking the ice. I was not so flush of good friends as to be willing to lose one. He might be desirous of putting business in my way. I went, and was received with cordiality, that even then seemed a little over effusive. We sat and talked of one thing and another for a long while, and I began to wonder when Mr. Foggart was coming to the point that most interested me. Several times he invited me to drink and smoke, but long usage to athletic training has given me a distaste for both practices, and I declined. At last he began to talk about myself. He was afraid that my professional prospects in this country were not great, but he had heard that in some of the colonies, South Africa, for example, young lawyers had brilliant opportunities. If you'd like to go there, he said, I've no doubt with a little capital, a clever man like you could get a grand practice together very soon. Or you might buy a share in some good established practice. I should be glad to let you have 500 pounds, or even a little more, if that wouldn't satisfy you. And I stood aghast. Why should this man, almost a stranger, offer me 500 pounds, or even more if that would satisfy me? What claim had I on him? It was very generous of him, of course, but out of the question. I was at least a gentleman and had a gentleman's self-respect. Meanwhile, he had gone wandering on in a halting sort of way.  I shouldn't like you to bear ill will because what has happened in the past, he said. Your late, your late lamented mother, I'm afraid, she had unworthy suspicions. I'm sure it was all the best for all parties. Your father always appreciated. I set back my chair and stood erect before him. This groveling wretch, forcing the words through his dry lips, was the thief who had made another of my father and had brought to miserable ends the lives of both my parents. Everything was clear. The creature went in fear of me, never imagining that I did not know him, and sought to buy me off, to buy me from the remembrance of my dead mother's broken heart for five hundred pounds, five hundred pounds that he had made my father's steel for him. I said not a word, but the memory of all my mother's bitter years, and a savage sense of this crowning insult to myself, took a hold upon me. And I was a tiger. Even then I verily believe that one word of repentance, one tone of honest remorse would have saved him. But he drooped his eyes, snuffled excuses, and stammered of unworthy suspicions and no ill will. I let him stammer.  I snatched the pistol from the mantelpiece, and thrusting it in his face, shot him where he sat. My subsequent coolness and quietness surprised me now. I took my hat and stepped toward the door. But there were voices on the stairs. The door was locked on the inside, and I left it so. I went back and quietly opened a window. Below was a clear drop into darkness, and above was a plain wall. But away to one side, where the slope of the gable sprang from the roof, an iron gutter ended, supported by a strong bracket. It was the only way. I got upon the sill and carefully shut the window behind me, for people were already knocking at the lobby door. From the end of the sill, holding on by the reveal of the window with one hand, leaning and stretching myself utmost, I caught the gutter, swung myself clear, and scrambled onto the roof. I climbed over many roofs before I found, in an adjoining street, a ladder lashed perpendicularly against the front of a house in course of repair. This, to me, was an easy opportunity of descent, not withstanding the boards fastened over the face of the ladder, and I availed myself of it. I have taken some time and trouble in order that you, so far as I am aware the only human being besides myself who knows me to be the author of Fogart's death, shall have at least the means of appraising my crime at its just value of culpability. How much you already know of what I have told you, I cannot guess. I am wrong, hardened, and flageotitious. I make no doubt, but I speak of the facts as they are. You see the thing, of course, from your own point of view, I from mine, and I remember my mother. Trusting that you will forgive the odd freak of a man, a criminal, let us say, who makes a confidant of the man set to hunt him down. I beg leave to be, sir, your obedient servant, Sidney Mason. I read the singular document through and handed it back to Hewitt. How does it strike you? Hewitt asked. Mason would seem to be a man of very marked character, I said, certainly no fool. And if his tale is true, Fogart is no great loss to the world. Just so, if the tale is true. Personally, I am disposed to believe it is. Where was the letter posted? It wasn't posted. It was handed in with the others from the front door letterbox this morning, in an unstamped envelope. He must have dropped it in himself during the night. Paper Hewitt proceeded holding it up to the light. Turkey mill ruled full scape. Envelope, blue, official shape, Piri's watermark, both quite ordinary and no special marks. Where do you suppose he's gone? Impossible to guess. Some might think he meant suicide by the expression beyond the reach even of your abilities to search. But I scarcely think he is the sort of man to do that. No, there is no telling. Something may be god at by inquiring at his late address, of course. But when such a man tells you he doesn't think you will find him, you may count upon its being a difficult job. His opinion is not to be despised. What shall you do? Put the letter in the box with the castes for the police. Fiat justizia, you know, without any question of sentiment. As to the apple, I really think if the police will let me, I'll make you a present of it. Keep it somewhere as a souvenir of your absolute deficiency in reflective observation in this case, and look at it whenever you feel yourself growing dangerously conceited. It should cure you. This is the history of the withered and almost petrified half apple that stands in my cabinet, among a number of Flint implements and one or two rather fine old Roman vessels. Of Mr. Sidney Mason we never heard another word. The police did their best, but he had left not a track behind him. His rooms were left almost undisturbed. And he had gone without anything in the way of elaborate preparation for his journey, and without leaving a trace of his intentions. End of Chapter 3. Chapter 4 of Martin Hewitt Investigator by Arthur Morrison. This LibriVox recording is in the public domain. Chapter 4. The Case of the Dixon Torpedo. Hewitt was very apt in conversation to dwell upon the many curious chances and coincidences that he had observed, not only in connection with his own cases, but also in matters dealt with by the official police, with whom he was on terms of pretty regular and indeed friendly acquaintanceship. He has told me many an anecdote of singular happenings to Scotland Yard officials, with whom he has exchanged experiences, of Inspector Nettings, for instance, who spent many weary months in a search for a man wanted by the American government, and in the end found, by the nearest accident, a misdirected call, that the man had been lodging next door to himself the whole time. Just as ignorant, of course, as was the Inspector himself, as to the enemy at the other side of the party wall. Also, of another Inspector, whose name I cannot recall, who, having been given rather meager and insufficient details of a man whom he anticipated having great difficulty in finding, went straight down the stairs of the office where he had received instructions, and actually fell over the man near the door, where he had stooped down to tie his shoe lace. There are cases, too, in which, when a great and notorious crime had been committed, and various persons had been arrested on suspicion, some were found among them who had long been badly wanted for some other crime altogether. Many criminals had met their deserts by venturing out of their own particular line of crime into another. Often a man who got into trouble over something comparatively small found himself in for a startlingly larger trouble, the result of some previous misdeed that otherwise would have gone unpunished. The ruble note forger, Mirsky, might never have been handed over to the Russian authorities had he confined his genius to forgery alone. It was generally supposed, at the time of his extradition, that he had communicated with the Russian Embassy with a view to giving himself up, that foolish proceeding on his part it would seem, since his whereabouts, indeed even his identity as the forger, had not been suspected. He had communicated with the Russian Embassy in his true, but for quite a different purpose, as Martin Hewitt well understood at the time. What that purpose was, is now for the first time published. The time was half past one in the afternoon, and Hewitt sat in his inner office examining and comparing the handwriting of two letters by the aid of a large lens. He put down the lens and glanced at the clock on the mantelpiece with a premonition of lunch. As he did so his clerk quietly entered the room with one of those printed slips which were kept for the announcement of unknown visitors. It was filled up in a hasty and almost illegible hand, thus. Name of visitor, F. Graham Dixon. Address, Chancery Lane. Business, private, and urgent. Show Mr. Dixon in, said Martin Hewitt. Mr. Dixon was a gaunt, worn looking man of fifty or so, well, although rather carelessly dressed and carrying in his strong, though drawn face and dullish eyes, the look that characterizes the lifelong, strenuous brain worker. He leaned forward anxiously in the chair which Hewitt offered him and told his story with a great deal of very natural agitation. You may possibly have heard, Mr. Hewitt. I know there are rumors of the new locomotive torpedo, which the government is about adopting. It is, in fact, the Dixon torpedo, my own invention, and in every respect, not merely in my own opinion, but in that of the government experts, by far the most efficient and certain yet produced. It will travel at least four hundred yards farther than any torpedo now made, with perfect accuracy of aim, a very great desert erotum, let me tell you, and will carry an unprecedentedly heavy charge. There are other advantages, speed, simple discharge, and so forth, that I needn't bother you about. The machine is the result of many years of work and disappointment, and its design has only been arrived at by a careful balancing of principles and means, which are expressed on the only four existing sets of drawings. The whole thing I need hardly tell you is a profound secret, and you may judge of my present state of mind when I tell you that one set of drawings has been stolen. From your house, from my office, in Chance Relayne, this morning, the four sets of drawings were distributed thus. Two were at the Admiralty Office, one being a finished set on thick paper, and the other a set of tracings therefrom, and the other two were at my office, one being a penciled set, uncolored, a sort of finished draft, you understand, and the other a set of tracings, similar to those at the Admiralty. It is this last set that is gone. The two sets were kept together in one drawer in my room. Both were there at ten this morning, of that I am sure, for I had to go to that very drawer for something else when I first arrived, but at twelve the tracings had vanished. You suspect some, but you probably? I cannot. It is a most extraordinary thing. Nobody has left the office except myself, and then only to come to you, since ten this morning, and there has been no visitor, and yet the drawings are gone. But you have searched the place? Of course I have. It was twelve o'clock when I first discovered my loss, and I have been turning the place upside down ever since, I and my assistants. Every drawer has been emptied, every desk and table turned over. The very carpet and linoleum have been taken up, but there is not a sign of the drawings. My men even insisted on turning all their pockets inside out, although I never for a moment suspected either of them, and it would take a pretty big pocket to hold the drawings, doubled up as small as they might be. You say you're men. There are two, I understand, had neither left the office? Neither, and they are both staying in now. Worstfold suggested that it would be more satisfactory if they did not leave till something was done toward clearing the mystery up, and although as I have said I don't suspect either in the least, I acquiesced. Just so. Now I am assuming that you wish me to undertake the recovery of these drawings? The engineer nodded hastily. Very good. I will go round to your office, but first perhaps you can tell me something about your assistants. Something it might be awkward to tell me in their presence, you know? Mr. Worstfold, for instance? He is my draftsman, a very excellent and intelligent man, a very smart man, indeed, and I feel sure quite beyond suspicion. He has prepared many important drawings for me. He has been with me nearly ten years now, and I have always found him trustworthy. But of course the temptation in this case would be enormous. Still I cannot suspect Worstfold. Indeed, how can I suspect anybody in the circumstances? The other, now? His name's Ritter. He is merely a tracer, not a fully skilled draftsman. He is quite a decent young fellow, and I have had him two years. I don't consider him particularly smart, or he would have learned a little more of his business by this time, but I don't see the least reason to suspect him. As I said before, I can't reasonably suspect anybody. Very well. We will get to Chanthry Lane now, if you please, and you can tell me more as we go. I have a cab waiting. What else can I tell you? I understand the position to be succinctly this. The drawings were in the office when you arrived. Nobody came out, and nobody went in, and yet they vanished. Is that so? That is so. When I say that absolutely nobody came in, of course I accept the postman. He brought a couple of letters during the morning. I mean that absolutely nobody came past the barrier in the outer office, the usual thing you know, like a counter with a frame of ground glass over it. I quite understand, but I think you said that the drawings were in a drawer in your own room, not the outer office, where the draftsmen are, I presume. That is the case. It is an inner room, or rather, a room parallel with the other and communicating with it, just as your own room is, which we have just left. But then you say you've never left your office, and yet the drawings vanished, apparently by some unseen agency while you were in the room? Let me explain more clearly. The cap was bowling smoothly along the strand, and the engineer took out a pocketbook and pencil. I fear, he proceeded, that I am a little confused in my explanation. I am naturally rather agitated. As you will see presently, my offices consist of three rooms, two at one side of a corridor, and the other opposite. Thus, he made a rapid pencil sketch. Readers note, the sketch shows three rooms separated by a corridor running horizontally through the middle. The room above the corridor is called the private room. Below the corridor are two rooms which connect to each other, the one on the left being the outer office, and on the right, the inner office. On the right wall of the inner office is marked the set of drawers in question with the letter D. And Readers note, in the outer office, my men usually work. In the inner office, I work myself. These rooms communicate as you see by a door. Our ordinary way in and out of the place is by the door of the outer office leading into the corridor, and we first pass through the usual lifting flap in the barrier. The door leading from the inner office to the corridor is always kept locked on the inside, and I don't suppose I unlock it once in three months. It has not been unlocked all morning. The drawer in which the missing drawings were kept, and in which I saw them at ten o'clock this morning, is at the place marked D. It is a large chest of shallow drawers in which the plans lie flat. I quite understand. Then there is the private room opposite. What of that? That is a sort of private sitting-room that I rarely use except for business interviews of a very private nature. When I said I never left my office, I did not mean that I never stirred out of the inner office. I was about in one room and another, both the outer and the inner offices, and once I went into the private room for five minutes, but nobody came either in or out of any of the rooms at that time. For the door of the private room was wide open, and I was standing at the bookcase. I had gone to consult a book just inside the door with a full view of the door's opposite. Indeed, Worsfold was at the door of the outer office most of the time. He came to ask me a question. Well, Hewitt replied, it all comes to the simple first statement. You know that nobody left the place or arrived except the postman, who couldn't get near the drawings, and yet the drawings went. Is this your office? The cab had stopped before a large stone building. Mr. Dixon alighted and led the way to the first floor. Hewitt took a casual glance around each of the three rooms. There was a sort of door in the frame of ground glass over the barrier to admit of speech with visitors. This door Hewitt pushed wide open and left so. He and the engineer went into the inner office. Would you like to ask Worsford and ridder any questions, Mr. Dixon inquired? Presently, those are their coats, I take it, hanging just to the right of the outer office door over the umbrella stand. Yes, those are all their things. Coats, hats, sticks, and umbrella. And those coats were searched, you say? Yes. And this is the drawer thoroughly searched, of course. Oh, certainly.  Well, of course, I must assume you made no mistake in your hunt. Now, tell me, did anybody know where these plans were beyond yourself and your two men? As far as I can tell, not a soul. You don't keep an office boy? No, there would be nothing for him to do, except to post a letter now and again, which Ritter does quite well for. As you are quite sure that the drawings were there at ten o'clock? Perhaps the thing scarcely matters, but I may as well know if your men have keys to the office. Neither. I have patent locks to each door, and I keep all the keys myself. If Worsford or Ritter arrive before me in the morning, they have to wait to be let in, and I am always present myself when the rooms are cleaned. I have not neglected precautions, you see. No. I suppose the object of the theft, assuming it is a theft, is pretty plain. The thief would offer the drawings for sale to some foreign government? Of course. They would probably command a great sum. I have been looking, as I need hardly tell you, to that invention to secure me a very large fortune, and I shall be ruined indeed if the design is taken abroad. I am under the strictest engagements to secrecy with the admiralty, and not only should I lose all my labor, but I should lose all the confidence reposed in me at headquarters should in fact be subject to penalties for breach of contract, and my career stopped forever. I cannot tell you what a serious business this is for me. If you cannot help me, the consequences will be terrible. Bad for the surface of the country too, of course. Of course. Now tell me this. It would, I take it, be necessary for the thief to exhibit these drawings to anybody anxious to buy the secret. I mean he couldn't describe the invention by word of mouth? Oh no, that would be impossible. The drawings are of the most complicated description and full of figures upon which the whole thing depends. Indeed, one would have to be a skilled expert to properly appreciate the design at all. Various principles of hydrostatics, chemistry, electricity, pneumatics, are most delicately manipulated and adjusted, and the smallest error or omission in any part would upset the whole. No, the drawings are necessary to the thing and they are gone. At this moment the door of the outer office was heard to open and somebody entered. The door between the two offices was a jar and Hewitt could see right through to the glass door left open over the barrier and into the space beyond. A well-dressed dark, bushy bearded man stood there carrying a handbag which he placed on the ledge before him. Hewitt raised his hand to enjoin silence. The man spoke in a rather high-pitched voice and with a slight accent. This Mr. Dixon, now of his in, he asked. He is engaged, answered one of the draftsmen, very particularly engaged. I am afraid you won't be able to see him this afternoon. Can I give him any message? This is two, the second time I have come today. Not two hours ago Mr. Dixon himself tells me to call again. I have a very important, very excellent steam packing to show him that is very cheap and the best of the market. The man tapped his bag. I have just taken orders from the largest railway companies. Cannot I see him for one second only? I will not detain him. Really, I'm sure you can't this afternoon. He isn't seeing anybody but if you'll leave your name. My name is Hunter but what's the good of that? He asked me to call a little later and I come and now he's engaged. It's a fairly gauge pity.  Hewitt stood still gazing through the small aperture in the doorway. You'd scarcely expect a man with such a name as Hunter to talk without accent, would you? He observed musingly. It isn't a French accent or a German but it seems foreign. You don't have to know him, I suppose. No, I don't. He called here about half past twelve, just while we were in the middle of our search and I was frantic over the loss of the drawings. I was in the outer office myself and told him to call later. I have lots of such agents here anxious to sell all sorts of engineering appliances. But what will you do now? Shall you see my men? I think, said Hewitt, rising, I think I'll get you to question them myself. Yes, I have a reason. Will you trust me with the key of the private room opposite? I will go over there for a little while you talk to your men in this room.  I can look after the outer office from across the corridor, you know. Ask each of them to detail his exact movements about the office this morning and get them to recall each visitor who has been here from the beginning of the week. I'll let you know the reason of this later. Come across to me in a few minutes. Hewitt took the key and passed through the outer office into the corridor. Ten minutes later Mr. Dixon, having questioned his draftsman, followed him. He found Hewitt standing before the table in the private room on which lay several drawings on tracing paper. See here Mr. Dixon, said Hewitt, I think these are the drawings you are anxious about. The engineer sprang toward them with a cry of delight. Why, yes, yes, he exclaimed, turning one of them over. Every one of them. But where, how, they must have been in the place after all, then.  Hewitt shook his head. I'm afraid you're not quite so lucky as you think, Mr. Dixon, he said. These drawings have most certainly been out of the house for a little while. Never mind now. We'll talk about that afterward. There is no time to lose. Tell me, how long would it take a good draftsman to copy them? They couldn't possibly be traced over properly in less than two or three and a half long days of very hard work. Dixon replied with eagerness. Ah, then it is as I fear that these tracings have been photographed. Mr. Dixon, and our task is one of every possible difficulty. If they had been copied in the ordinary way, one might hope to get hold of the copy. But photography upsets everything. Copies can be multiplied with such amazing facility that once the thief gets a decent start, it is almost hopeless to checkmate him. The only chance is to get at the negatives before copies are taken. I must act at once, and I fear between ourselves it may be necessary for me to step very distinctly over the line of the law. In this matter, you see, to get at those negatives may involve something very like housebreaking. There must be no delay, no waiting for legal procedure, or the mischief is done. Indeed, I very much question whether you have any legal remedy, strictly speaking. Mr. Hewitt, I implore you do what you can. I need not say that all I have is at your disposal. I will guarantee to hold you harmless for anything that may happen. But do I entreat you do everything possible? Think of what the consequences may be. Well, yes, so I do, Hewitt remarked with a smile. The consequences to me, if I were charged with housebreaking, might be something that no amount of guarantee could mitigate. However, I will do what I can, if only from patriotic motives. Now I must see your tracer ritter. He is the traitor in the camp. Ritter? But how? Never mind that now. You are upset and agitated and had better not know more than is necessary for a little while, in case you say or do something unguarded. With Ritter I must take a deep course. What I don't know I must appear to know, and that will seem more likely to him if I disclaim acquaintance with what I do know. But first, put these tracings safely away, out of sight. Dixon slipped them behind his bookcase. Now, Hewitt pursued, call Mr. Worsfold and give him something to do that will keep him in the inner office across the way, and tell him to send Ritter here. Mr. Dixon called his chief draftsman and requested him to put in order the drawings in the drawers of the inner room that had been disarranged by the search, and to send Ritter, as Hewitt had suggested. Ritter walked into the private room with an air of respectful attention. He was a puffy-faced, unhealthy-looking young man, with very small eyes, and a loose, mobile mouth. Set down, Mr. Ritter, Hewitt said, in a stern voice. Your recent transactions with your friend Mr. Hunter are well known to both Mr. Dixon and myself. Ritter, who had at first leaned easily back in his chair, started forward at this, and paled. You are surprised, I observe, but you should be more careful in your movements, out of doors, if you do not wish your acquaintances to be known. Mr. Hunter, I believe, has the drawings, which Mr. Dixon has lost, and if so, I am certain that you have given them to him. That, you know, is theft, for which the law provides a severe penalty. Ritter broke down completely and turned appealingly to Mr. Dixon. Oh, sir, he pleaded. It isn't so bad, I assure you. I was tempted, I confess, and hid the drawings, but they are still in the office, and I can give them to you really I can. Indeed, Hewitt went on. Then, in that case, perhaps you'd better get them at once, just go and fetch them in. We won't trouble to observe your hiding place. I'll only keep this door open to be sure you don't lose your way, you know, down the stairs, for instance. The wretched Ritter, with hanging head, slunk into the office opposite. Presently, he reappeared, looking, if possible, gaslier than before. He looked irresolutely down the corridor, as if meditating a run for it, but Hewitt stepped toward him and motioned him back to the private room. You mustn't try any more of that sort of humbug, Hewitt said, with increasing severity. The drawings are gone and you have stolen them. You know that well enough. You mustn't try any more of that sort of humbug, Hewitt said, with increasing severity. The drawings are gone and you have stolen them. You know that well enough. Now attend to me.  But unfortunately your accomplice, who calls himself Hunter, but who has other names besides that, as I happen to know, has the drawings and it is absolutely necessary that these should be recovered. I am afraid that it will be necessary, therefore, to come to some arrangement with this scoundrel to square him, in fact. Now just take that pen and paper and write to your confederate as I dictate. You know the alternative if you cause any difficulty. Ritter reached tremblingly for the pen. Address him in your usual way, Hewitt proceeded. Say this, there has been an alteration in the plans. Have you got that? There has been an alteration in the plans. I shall be alone here at six o'clock. Period. Please come without fail. Period. Have you got it? Very well. Sign it and address the envelope. He must come here and then we may arrange matters. In the meantime you will remain in the inner office opposite. The note was written and Martin Hewitt, without glancing at the address, thrust it into his pocket. When Ritter was safely in the inner office, however, he drew it out and read the address. I see, he observed, he uses the same name, Hunter. Twenty-seven little Carleton Street. West Minster is the address, and there I shall go at once with the note. If the man comes here, I think you had better lock him in with Ritter and send for a policeman. It may at least frighten him. My object is, of course, to get the man away, and then, if possible, to invade his house, in some way or another, and steal or smash his negatives, if they are there and to be found. Stay here in any case till I return, and don't forget to lock up those tracings. It was about six o'clock when Hewitt returned, alone, but with a smiling face that told of good fortune at first sight. First Mr. Dixon, he said, as he dropped into an easy chair in the private room, let me ease your mind by the information that I have been most extraordinarily lucky. In fact, I think you have no further cause for anxiety. Here are the negatives. They were not all quite dry. When I, well, put, stole them, I suppose I must say, so that they have stuck together a bit, and probably the films are damaged. But you don't mind that, I suppose. He laid a small parcel wrapped in a newspaper on the table. The engineer hastily tore away the paper and took up five or six glass photographic negatives of a half plate size, which were damp and stuck together by the gelatine films in couples. He held them, one after another, up to the light of the window, and glanced through them. Then with a great sigh of relief, he placed them on the hearth and pounded them to dust and fragments with the poker. For a few seconds neither spoke. Then Dixon, flinging himself into a chair, said, Mr. Hewitt, I can't express my obligation to you. What would have happened if you had failed? I prefer not to think of. But what shall we do with Ritter now? The other man hasn't been here yet, by the way. No, the fact is I didn't deliver the letter. The worthy gentleman saved me a world of trouble by taking himself out of the way. He would laugh. I'm afraid he has rather got himself into a mess by trying two kinds of theft at once. And you may not be sorry to hear that his attempt on your torpedo plans is likely to bring him a dose of penal servitude for something else. I'll tell you what has happened. Little Carleton Street, Westminster, I found to be a seedy sort of place. One of those old streets that have seen much better days. A good many people seem to live in each house. And they are fairly large houses, by the way. And there is quite a company of bell handles on each doorpost all down the side, like organ stops. A barber had possession of the ground floor, front of number twenty-seven, for trade purposes. So to him I went. Can you tell me, I said, where in this house I can find Mr. Hunter? He looked doubtful, so I went on. His friend will do, you know, I can't think of his name, foreign gentleman, dark, with a bushy beard. The barber understood it once. Oh, that's Murski, I expect, he said. Now I come to think of it. He has had letters addressed to Hunter once or twice. I've took him in, top floor back. This was good so far. I had got at Mr. Hunter's other alias. So by a way of possessing him with the idea that I knew all about him, I determined to ask for him as Murski, before handing over the letter addressed to him as Hunter. A little bluff of that sort is invaluable at the right time. At the top floor back I stopped at the door and tried to open it at once, but it was locked. I could hear somebody scuttling about within, as though carrying things about, and I knocked again. In a little while the door opened about a foot, and there stood Mr. Hunter, or Murski, as you like. The man who, in the character of a traveler in steam packing, came here twice today. He was in his shirt sleeves and cuddled something under his arm, hastily covered with a spotted pocket handkerchief. I have called to see Mr. Murski, I said, with a confidential letter. Oh, yes, yes, he answered hastily. I know, I know, excuse me, one minute. And he rushed off down the stairs with his parcel. Here was a noble chance. For a moment I thought of following him, in case there might be something interesting in the parcel, but I had to decide in a moment and I decided on trying the room. I slipped inside the door and finding the key on the inside locked it. It was a confused sort of room with a little iron bedstead in one corner and a sort of rough, bordered enclosure in another. This I rightly conjectured to be the photographic dark room, and I made for it at once. There was plenty of light within when the door was left open, and I made it once for the drying rack that was fastened over the sink. There were a number of negatives on it, and I began hastily examining them one after another. In the middle of this our friend Murski returned and tried the door. He rattled violently at the handle and pushed, then he called. At this moment I had come upon the first of the negatives you have just smashed. The fixing and washing had evidently only lately been completed and the negative was drying on the rack. I seized it, of course, and the others which stood by it. Who are you there inside? Murski shouted indignantly from the landing. Why, for you go into my room like that. Open this door at once or I call police. I took no notice. I had got the full number of negatives, one for each drawing, but I was not by any means sure that he had not taken an extra set, so I went on hunting down the rack. There were no more, so I set to work to turn out all the undeveloped plates. It was quite possible you see that the other set, if it existed, had not yet been developed. Murski changed his tune. After a little more banging and shouting I could hear him kneel down and try the keyhole. I had left the key there so that he could see nothing, but he began talking softly and rapidly through the hole in a foreign language. I did not know it at least, but I believe it was Russian. What had led him to believe I understood Russian I could not at the time imagine, though I have a notion now. I went on ruining his stock of plates. I found several boxes apparently of new plates, but as there was no means of telling whether they were really unused or were merely undeveloped, but with chemical impress of your drawings on them, I dragged everyone ruthlessly from its hiding place and laid it out in the full glare of the sunlight, destroying it thereby, of course, whether it was unused or not.  Perhaps his conscience was not sufficiently clear to warrant an appeal to the police, but it seemed to me rather probable at the time that that was what he was going for. So I hurried on with my work. I found three dark slides, the parts that carried the plates in the back of the camera, you know, one of them fixed in the camera itself. These I opened and exposed the plates to ruination as before. I suppose nobody ever did so much devastation in a photographic studio in ten minutes as I managed. I had spoiled every plate I could find and had the developed negatives safely in my pocket when I happened to glance at a porcelain washing well under the sink. There was one negative in that, and I took it up. It was not a negative of a drawing of yours, but of a Russian twenty-ruble note. This was a discovery. The only possible reason any man could have for photographing a banknote was the manufacture of an etched plate for the production of forged copies. I was almost as pleased as I had been at the discovery of your negatives. He might bring the police now as soon as he liked I could turn the tables on him completely. I began to hunt about for anything else relating to this negative. I found an inking roller, some old pieces of blanket used in printing from plates and in a corner on the floor heaped over with newspapers and rubbish, a small copying press. There was also a dish of acid, but not an etched plate or a printed note to be seen. I was looking at the press with the negative in one hand and the inking roller in the other when I became conscious of a shadow across the window. I looked up quickly and there was Meersky hanging over from some ledge or projection to the side of the window and staring straight at me with a look of unmistakable terror and apprehension. The face vanished immediately. I had to move a table to get at the window and by the time I had opened it there was no sign or sound of the rightful tenant of the room. I had no doubt now of his reason for carrying a parcel downstairs. He probably mistook me for another visitor who was expecting and knowing he must take this visitor into his room, through the papers and rubbish over the press, and put up his plates and papers in a bundle and secreted them somewhere downstairs lest his occupation should be observed. Plainly, my duty now was to communicate with the police. So by help of my friend the barber downstairs a messenger was found and a note sent over to Scotland Yard. I awaited, of course, for the arrival of the police and occupied the interval in another look round, finding nothing important, however. When the official detective arrived he recognized at once the importance of the case. A large number of forged Russian notes have been put into circulation on the continent lately, it seems, and it was suspected that they came from London. The Russian government have been sending urgent messages to the police here on the subject. Of course, I said nothing about your business, but while I was talking with the Scotland Yard man a letter was left by a messenger addressed to Mirsky. The letter will be examined, of course, by the proper authorities, but I was not a little interested to perceive that the envelope bore the Russian imperial arms above the words Russian Embassy. Now, why should Mirsky communicate with the Russian Embassy? Certainly not to let the officials know that he was carrying on a very extensive and lucrative business in the manufacture of spurious Russian notes. I think it is rather more than possible that he wrote, probably before he actually got your drawings, to say that he could sell information of the highest importance, and this letter was a reply. Further, I think it quite possible that when I asked for him by a Russian name and spoke of a confidential letter, he at once concluded that I had come from the Embassy in answer to his letter. That would account for his addressing me in Russian through the keyhole. And, of course, an official from the Russian Embassy would be the very last person in the world whom he would like to observe any indications of his little etching experiments. But, anyhow, be that as it may, he concluded, your drawings are safe now, and if once Mirsky is caught, and I think it likely for a man in his shirt sleeves with scarcely any start, and perhaps no money about him, hasn't a great chance to get away, if he is caught, I say, he will probably get something handsome at St. Petersburg in the way of imprisonment, or Siberia, or what not, so that you will be amply avenged. Yes, but I don't at all understand this business of the drawings even now. How in the world were they taken out of the place, and how in the world did you find it out? Nothing could be simpler, and yet the plan was rather ingenious. I'll tell you exactly how the thing revealed itself to me. From your original description of the case, many people would consider that an impossibility had been performed. Nobody had gone out, and nobody had come in, and yet the drawings had been taken away. But an impossibility is an impossibility, after all, and as drawings don't run away of themselves, plainly somebody had taken them unaccountable, as it might seem. Now, as they were in your inner office, the only people who could have got at them beside yourself were your assistants, so that it was pretty clear that one of them, at least, had something to do with the business. You told me that Worsford was an excellent and intelligent draftsman. Well, mediated treachery would probably be able to carry away the design in his head, at any rate, a little at a time, and would be under no necessity to risk the stealing of them. But Ritter, you remark, was an inferior sort of man. Not particularly smart, I think were your words, only a mechanical sort of tracer. He would be unlikely to be able to carry in his head the complicated details of such designs as yours, and being in a subordinate position and continually overlooked, he would find it impossible to make copies of the plan in the office, so that, to begin with, I thought I saw the most probable path to start on. When I looked around the rooms, I pushed open the glass door of the barrier, and left the door to the inner office ajar, in order to be able to see anything that might happen in any part of the place, without actually expecting any definite development. While we were talking, as it happened, our friend Mirsky, or Hunter, as you please, came into the outer office, and my attention was instantly called to him by the first thing he did. Did you notice anything peculiar yourself? No, really, I can't say I did. He seemed to behave much as any traveler or agent might. Well, what I noticed was the fact that as soon as he entered the place, he put his walking stick into the umbrella stand over there by the door, close by where he stood, a most unusual thing for a casual caller to do before even knowing whether you were in. This made me watch him closely. I perceived with increased interest that the stick was exactly of the same kind and pattern as one already standing there. Also a curious thing. I kept my eyes carefully on those sticks, and was all the more interested and edified to see when he left that he took the other stick, not the one he came with from the stand, and carried it away, leaving his own behind. I might have followed him, but I decided that more could be learned by staying, as in fact proved to be the case. This by the by is the stick he carried away with him. I took the liberty of fetching it back from Westminster, because I can see it to be Ritter's property. Hewitt produced the stick.  Hewitt bent it across his knee and laid it on the table. Yes, Dixon answered. That is Ritter's stick. I think I have often seen it in the stand. But what in the world, one moment I'll just fetch the stick Mirsky left behind. And Hewitt stepped across the corridor. He returned with another stick, apparently an exact facsimile of the other, and placed it by the side of the other. When your assistance went into the room, I carried this stick off for a minute or two. I knew it was not Wersfold, because there was an umbrella there with his initial on the handle. Look at this. Martin Hewitt gave the handle a twist and rapidly unscrewed it from the top. Then it was seen that the stick was a mere tube of very thin metal painted to appear like a Malacca cane. It was plain at once that this was no Malacca cane that wouldn't bend. Inside it I found your tracings rolled up tightly. You can get a marvelous quantity of thin tracing paper into a small compass by tight rolling. And this, this was the way they were brought back, the engineer exclaimed. I see that clearly. But how did they get away? That's as mysterious as ever. Not a bit of it. See here. Mirsky gets hold of Ritter and they agree to get your drawings and photograph them. Ritter is to let his confederate have the drawings and Mirsky is to bring them back as soon as possible so that they shan't be missed for a moment. Ritter habitually carries this Malacca cane and the cunning of Mirsky at once suggests that this tube should be made in outward facsimile. This morning Mirsky keeps the actual stick and Ritter comes to the office with the tube. He seizes the first opportunity, probably when you were in this private room, and Warsaw was talking to you from the corridor to get at the tracings, roll them up tightly, and put them in the tube, putting the tube back into the umbrella stand. At half past twelve or whenever it was, Mirsky turns up for the first time with the actual stick and exchanges them. Just as he afterward did when he brought the drawings back. Yes, but Mirsky came half an hour after they were... Oh yes, I see.  I was forgetting. Of course, when I first missed the tracings they were in this walking stick safe enough and I was tearing my hair out with an arm's reach of them. Precisely. And Mirsky took them away before your very eyes. I expect Ritter was in a rare funk when he found that the drawings were missed. He calculated no doubt on your not wanting them for the hour or two they would be out of the office. How lucky that it struck me to jot a pencil note on one of them. I might easily have made my note somewhere else and then I should never have known that they had been away. Yes, they didn't give you any too much time to miss them. Well, I think the rest is pretty clear.  You identified the tracings and found none missing and then my course was pretty clear though it looked difficult. I knew you would be very naturally indignant with Ritter so as I wanted to manage him myself I told you nothing of what he had actually done for fear that in your agitated state you might burst out with something that would spoil my game. To Ritter I pretended to know nothing of the return of the drawings or how they had been stolen, the only things I didn't know with certainty, but I did pretend to know all about Meersky or Hunter when as a matter of fact I knew nothing at all except that he probably went under more than one name. That put Ritter into my hands completely. When he found the game was up he began with a lying confession believing that the tracings were still in the stick and that we knew nothing of their return he said that they had not been away and that he would fetch them as I had expected he would. I let him go for them alone and when he returned utterly broken up by the discovery that they were not there I had him all together at my mercy. You see if he had known that the drawings were all the time behind your bookcase might have brazened it out sworn that the drawings had been there all the time and we could have done nothing with him. We couldn't have sufficiently frightened him by a threat of prosecution for theft because there the things were in your possession to his knowledge. As it was he answered the helm capitely gave us Mirsky's address on the envelope and wrote the letter that was to have got him out of the way while I committed burglary if that disgraceful expedient had not been rendered unnecessary. On the whole the case has gone very well. It has gone marvelously well thanks to yourself but what shall I do with Ritter? Here is his stick. Knock him downstairs with it if you like. I should keep the tube if I were you as a memento. I don't suppose the respectable Mirsky will ever call to ask for it but I should certainly kick Ritter out of doors or out of the window if you like without delay. Mirsky was caught and after two remands at the police court was extradited on the charge of forging Russian notes. It came out that he had written to the Embassy as Hewitt had surmised stating that he had certain valuable information to offer and the letter which Hewitt had seen delivered was an acknowledgement and a request for more definite particulars. This was what gave rise to the impression that Mirsky had himself informed the Russian authorities of his forgeries. His real intent was very different but was never guessed. I wonder Hewitt has once or twice observed whether after all it would not have paid the Russian authorities better on the whole if I had never investigated Mirsky's little note factory. The Dixon torpedo was worth a good many 20 ruble notes. End of chapter 4


Moving to inaugural state, where the governor, Dr. Peter Mba, has commanded the security agencies, especially the Nigerian Army, for improved security and end to sit at home in the state, assuring that his administration would not let down his guard. This was even as the Army has reiterated that security could only get better, giving the level of resources and manpower deployed in the state, assuring citizens of their safety as they go about their businesses. The governor gave the commendation when he received the general officer commanding 82 Division of the Nigerian Army Enugu Major General Hassan Dada at the government house on Tuesday. He said the improved security would aid his administration's promise to grow the state's economy in an unprecedented manner as the growth was going to come from private sector investment. When we took over, we immediately identified the challenges of insecurity as the big elephant in the room. We also recognized that the continual Mondays sit at home was not only creating this perception of insecurity in our region, but that it was doing so much damage to our psychology as a people, our social well-being, and our economy. So we moved against it. We made a pronouncement to put an end to the Mondays sit at home. My task will not be easy without meeting the chiefs of the South States. And you are certainly seeing that's why I felt it necessary that they had to come around and pray in my doorbell, do my formalization visit to the office, and know what are the issues that we need to sort out to see how I can implement the Mondays that are doing handover through


and the system is shift invariant if and only if the output is also y of n minus n 0. Now, here again some things need to be qualified, firstly that this needs to hold for all x n and this needs to hold for all n 0, this is very important. This is the statement formally now we need to understand it. You see the statement is that when I shift the input by an integer number of samples, please note we are only asking for n 0 to be an integer. So, when I shift the input by an integer number of samples, the only consequence on the output is that the output is shifted and by the same number of samples that is important. Not only that this holds for every possible input and every such shift. So, when I wish to prove a system is shift invariant, I must prove it independent of what input I have given it and independent of what shift I have given the input, this is important. Of course, when I want to disprove, I only need to take a count example and now let us take an example of both. Let us take an example of a shift invariant system. In fact, we can go back to the very system that we had discussed as linear. So, take the system y of n is 3 times x n plus 4 times x of n minus 1 that we had taken a minute ago. Now, if I were this is so you know what it means is when I put x n into the system, I get y n according to this. Now, if I were to put x of n minus n 0 into the system, it is a very small subtle point, but what I would get you see how would I get the output? I would get the output by replacing n by n minus n 0 in both places. So, the output would be 3 times x of n minus n 0 as expected plus 4 times x of now replace n by n minus n 0 minus 1 that is easy. And of course, it is very easy to say that this is equal to y of n minus n 0. You see because when you replace y of when you replace n by n minus n 0 here, you get exactly the same expression you know. This is y of n minus n 0. So, you know it is not too difficult to visualize what is happening here. At every point in the output, you are taking 3 times the past 3 times the present input sample and 4 times the past one. So, if I were to shift the say the whole input by n 0 samples at every point, I would be getting the same input, but shifted by n 0 sample. So, whatever was happening n 0 samples before would now happen at this point right. So, it is I mean even intuitively it is not too difficult to see the system is shift invariant. In fact, you know it looks like shift invariance is a trivial property. We expect this to happen rather too frequently, but we will see in a minute that we can easily construct a count example of a system which does not obey this. So, let us now take a very simple example of a system which does not obey this. So, let us take the system y of n is n times x of n. Now, you know one remark here typically shift variance that means disobedience of shift invariance tends to happen when you are looking at the clock in informal language. So, you know if a system looks only at the input and does what it wants to the system tends to be shift invariant, but when the system also takes a peak at the clock underlying the input then shift invariance is disobeyed. Now, in this system the output at a given point in time the output at the point n is the input at the point n and the system is all the time sneakingly taking a look at the clock. So, it looks at the sample instant and multiplies by the sample instant that is where the problem comes. So, now let us take two inputs let us take x n now we bring in some notation we bring in a very important sequence that we will often use we call it the unit impulse sequence. We will use the sequence very frequently in future we will denote it by delta n and this sequence is 1 for n equal to 0 and 0 for n not equal to 0. So, it is 1 only at one place it is 1 at n equal to 0 and it is 0 everywhere else. Now, I encourage you to work out what happens when this input is shifted by 3 samples forward find out the output. In fact, I ask you what is the output in this case when I give an input which is 1 at n equal to 0 and 0 everywhere else what output do I expect 0 everywhere because you know the place where it is 1 n is equal to 0. So, it gets multiplied by 0 everywhere else the input itself is 0. So, it gets multiplied by 0 anyway. So, in this case y n is equal to 0 for all n when x n is equal to delta n this I repeat this sequence this unit impulse sequence is going to be very useful to us in future too. Now, let us find out what happens when we give the input delta n minus 3. So, I ask you what happens when we give the input delta n minus 3 that means essentially now what is delta n minus 3 delta n minus 3 is going to be equal to 1 when n minus 3 is 0 or n equal to 3 and 0 else. So, it is 1 only at 1 point that is n equal to 3. Now, what is the output going to be the output is going to be at the point n equal to 3 it is going to be multiplied by 3 and therefore, we can write the output. In fact, we can write the output down explicitly we can express the output in terms of delta y n in this case is 3 times delta n minus 3 when x n is equal to delta n minus 3. In fact, we can generalize this in general y n is equal to capital N times delta n minus capital N whenever x n is delta n minus capital N for any integer n and obviously, this system is not shift invariant. If it were shift invariant then I should have got the output 0 here too, but I do not and you see why it is not shift invariant. The disobedience of shift invariance has come because the system is sneakingly taking a look at the clock when finding out when you bring in the clock in your output there is a problem shift invariance is disobedient. We need to take a break at this point to reflect on where we are we have dealt with two very important properties linearity and shift invariance. We now need to deal with others like stability, but we will take a break as I said and look more deeply at just these two properties because together they give us a great deal. If a system is linear and shift invariant then we will now prove a very important result and the result is I need to perform just one experiment on that system to characterize the system completely, only one experiment required and in fact that experiment will involve the very sequence that we mentioned a minute ago namely the unit impulse sequence. I told you that unit impulse sequence is very important, it tells us a great deal and it will tell us a great deal in context of linear shift invariant system. So we will show that the following is true. A linear shift invariant system is completely characterized by its response to a unit impulse sequence delta n. We need to take a minute to reflect on what is meant by complete characterization. When would I say a system has been completely characterized? Let me ask you, when would you say a system has been completely characterized? So I will repeat some of the responses I have. One response says that I know the output whenever I give it an input that is one. The other response says that I am trying to excite all frequency components. Any other responses? The relation between the input and the output can be determined. Yes, same thing. Transfer function can be obtained. Yes, you can predict the output for any input. Yes, any input signal, can you repeat that? Any input signal can be constructed from, but how does that characterize the system? He says the, any input signal can be constructed by, that does not tell me that the system is carrying. What do you mean by, my question is what do you mean by characterizing a system? You know I will tell you a story and I think the story is relevant before we conclude the class because very many of you must be studying the subject after possible exposure to some of the concepts in other contexts. There is a story of a master and a disciple and the disciple was asked to bring a cup and a jug of water. So the disciple was asked to fill the cup partially first by the master and then you know the disciple was again asked to continue pouring water into the cup even after it reached its brim. Naturally the water began to overflow. After a while the disciple wondered why this was being asked of him. Why am I continuing to pour water into a cup which is already full? The master said that is exactly what I am trying to point out. If I need to explain certain things to you, it is important that you have space in the place where you store what has been explained. If you come with that storage full, it is very important to put something into it. So for example, the question here I bring this up in this context because very often we already have our notions of what systems need to be like, what system definition. For example, some people I am not trying to dissuade response, but I am just trying to tell you that it is important that you begin with the assumptions that have been made and the question that has been asked and the context that has been addressed and not try to bring in extraneous things when trying to understand concepts. For example, some people mention transfer function, some people mention frequency. Now you see at this moment we are just asking what characterizes the system. We have not said anything about transfer, we do not even know if the system has a transfer function and if we do not even know if the system has been given a sinusoidal input. We just know the system has an input and an output and our answer naturally should be related to that. So we do not bring in things and you see when we try and answer questions that are fundamental to the subject, it is very important only to proceed from assumptions that are made there. So here we have not made an assumption about any transfer function or we do not even know if a transfer function exists. Similarly, we have not even made an assumption about any particular kind of input. So characterization, so it improves or I mentioned this as a word of caution because it is very easy sometimes to be misled by our knowledge in other contexts. For example, some people think characterizing a system means being able to write an explicit relation between the input and output. No, characterizing a system means just one thing. It means that no matter what input I give it, I know what the output is and that is all that we can say because we are just talking about a general system at this point in time. We have no knowledge of whether the system, you see we are of course going to characterize a particular class of systems. But then the question that is before us is what is meant by characterization. Characterization means if I give it an input, I can determine the output. Whether I can determine the output by an explicit relation or an implicit relation or by observation is a different issue. In fact, now we will soon show that the output can be determined constructively. Constructively means I can actually write down a process by which I can construct. But that is a bonus that you get. It is not a part of characterization. So let us make a statement about characterization. Characterization means being able to determine the output given any input. In fact, there is nothing more to a system. If I know the output for every input, the system is determined. Now we shall proceed to prove this in the next lecture. What I will do is to give you what I call a trailer of the proof. And the trailer of the proof is as follows. You see what we will show is that as one of you said, any input can either ultimately be thought of as a combination of unit impulses appropriately shifted. Now because a system which is linear and shift invariant has two properties. One is since it is shift invariant, if I know what it does to a unit impulse, I know what it does when I shift the unit impulse. Because it is homogeneous, I know what it does when I scale the impulse. So if I put a unit impulse and multiply it by a constant, I know what the output will be. Further, if I take two such impulses located at different points and if I add them, I know what the output will be. If this were given, so I use these three parts of the system description. The shift invariance, the additivity and the homogeneity. By using these three properties together, we shall prove this theorem as the first step in the lecture to come. With that then we conclude this lecture. We will meet again for the next one.