The Chemical Adventures of Sherlock Holmes: The Blackwater Escape

Chemistry for Everyone

The Chemical Adventures of Sherlock Holmes: The Blackwater Escape Thomas G. Waddell* and Thomas R. Rybolt Department of Chemistry, University of Tennessee at Chattanooga, Chattanooga, TN 37403; *[email protected]

The following story is a chemical mystery with an emphasis on qualitative inorganic analysis, laboratory observations, and oxidation–reduction processes. This is the 14th article in a series presenting a scientific problem in mystery format in the context of the popular and beloved characters Sherlock Holmes and Dr. Watson (1, 2). There is a break in the story where readers (students and teachers) can ponder and solve the mystery. Sherlock Holmes provides his solution in the paragraphs following this break.

The Story On a day in early June, in the year 1920, I made an automobile trip to the Downs of Sussex and the farm where my friend and colleague Sherlock Holmes kept bees and tended to a small garden. In the years since his retirement I had seen my friend only on rare occasions, holidays and some birthdays, his or mine. My medical practice was still active but remained small, as it had been even when Holmes and I kept our rooms at 221B Baker Street. It was a wonderful day and it had been some months since we had been together. Moreover, I had just finished re-reading Holmes’s treatise The Art of Detection and I was thirsting for long discussions and memories shared with the Master Detective. As I drove up to his cottage, the man himself stood in the doorway. “Watson,” he cried. “How marvelous to see you!” The years had been kind to Holmes. His erect frame had not changed in the least and his eyes twinkled with merriment. His dark hair, combed straight back in his usual manner, was salted with a stately gray. Solitary living suited him well. With the curious exception of myself, Sherlock Holmes had rarely sought the company of others. We had exchanged our usual greetings, when a dark sedan, which I had not noticed before, pulled in behind my own roadster. An elderly man climbed slowly from behind the wheel and walked carefully but confidently up the walk to where we were standing. “Why it’s my old colleague Inspector Forrester,” Holmes said. “You remember him don’t you, Watson, from the case that you once chronicled as the “Reigate Puzzle”?” I did remember him slightly. “Welcome, Inspector!” Holmes exclaimed. “Watson has just arrived and we shall make tea and talk of old times.” “I regret, Mr. Holmes, that my visit is not a pleasant one. I have frightening news. Mouse Mathison has escaped from Blackwater.” Holmes’s cheerful mood evaporated. “When?” he asked in a low voice. “Last night. Under the circumstances, and since I was down this way, I felt that it was only right for me to warn you.” “Warn Holmes?” I queried. “About what? Holmes is retired. He need not trouble himself anymore regarding the criminal element of England.” “You are wrong this time, my friend,” Holmes re-

sponded. “I must trouble myself very much. Some years ago I testified in court against Mouse Mathison and he was subsequently convicted of seven counts of conspiracy to produce explosions. His tiny stature is in contrast to his enlarged vindictive nature. He has been in Blackwater Prison for ten years and my sources tell me that he has never ceased threatening to obtain his revenge.” “But Holmes,” I pleaded, “what will you do?” “He must be found, Watson. He is a danger not only to me, but also to the populace of England. What do you say? Is the game afoot once more?” “You may count on me, Holmes. I will accompany you to the earth’s end. You know that.” “Capital, Watson!” he cried in the old way, rubbing his hands together. “May we ride to Blackwater in your fine roadster? No more hansom cabs for us, good fellow.” Thus, we found ourselves plummeting the highways toward Blackwater Prison. I had only learned to drive an automobile a few months ago, and, in response to Holmes’s urgings, our velocity was in excess of my habit. Holmes, as always, was immune to the danger. His hands rested lightly in his lap. My hands gripped the steering wheel tightly. “At Blackwater, Watson, we must investigate the escape scene and conduct the necessary interviews. Time is of an essence. I am most curious to learn the method of Mathison’s escape.” Later, as we walked with Warden Gruner Hobbs down the long, stone corridors of the prison, we began to learn the details of the escape. “The window in Mathison’s cell has two steel bars, Mr. Holmes,” explained Warden Hobbs. “One of the bars was somehow cut or broken and bent out allowing his escape. It is a short drop to a grassy surface outside and, indeed, it appears that Mouse struggled out the window. How the bar was severed I do not know. We are glad to have your help in this matter, sir. Well, here is Mouse’s cell. We have not touched anything since we discovered that he was gone.” Holmes entered the cell first and sniffed the air, as would a bloodhound. “What’s this, vinegar?” “Of course, Mr. Holmes,” Hobbs replied. “Mouse was very fond of fish and chips. We serve it up quite often at Blackwater. The potatoes and the river catfish are cheap and plentiful. Mouse always used a generous quantity of vinegar, more even than the English tradition, I imagine.”

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The cell was lit by a single, dim electric bulb supplied by a direct current1 and whose socket was attached by screws to two twisted strands of wire. The bulb was thus suspended at eye level, a few feet from a faded curtain, which covered the only window in the cell. I watched Holmes leisurely examine the contents of this desperate enclosure. There was a tin of tea and a small can of sugar, among other items cluttered about. On the wall opposite the bed was a low bookshelf holding a few thick volumes. Holmes read the titles to us aloud. “Ahh, two novels of Dickens, a chemistry textbook, Mr. Somerset Maugham’s Of Human Bondage—very appropriate don’t you think—, the poems of Robert Browning, Gems and Mineralogy, and a manual of brick masonry. Indeed, Warden Hobbs, our man was quite a reader.” “He was that, Mr. Holmes, and up until yesterday he was a model prisoner. Over time, he earned himself what privileges we allow, he did.” “What privileges might those be?” Holmes asked. “Why nothing out of the ordinary, Mr. Holmes,” the Warden replied. “He had the use of an electric light, as you see. Also, his mother was allowed to visit him. Maybe three months ago, she brought him some sugar, a spoon, and tea. Also, that mineralogy book is from her. And his brother Sam Mathison, a respectable brick mason down in the village, he visited Mouse also. Maybe two months ago, Sam brought him some hydrogen peroxide to treat a nasty scrape Mouse had across his knuckles. That book on brick and stone masonry is from Sam, too, I believe.” “Did no one else come to his cell?” Holmes queried. “Only the guard, Mr. Holmes. His name is Brun M. Simpson.” “And what special gifts did this Mr. Simpson supply?” Holmes asked with some sarcasm. “Please don’t misjudge us, Mr. Holmes,” the warden countered. “Mouse earned these privileges by good behavior. This is a proven policy in modern prisons. But in answer to your question, over recent weeks, the guard brought him extra bottles of vinegar for his fish and chips, and also a book entitled The Life and Work of Michael Faraday, 1791–1867. These items are around the cell here if we look. There’s the Faraday book on the floor in the corner.” The warden pointed but Holmes seemed oblivious. “Will I be able to question these three?” Holmes asked. “The mother and brother are usually available, Mr. Holmes,” he replied. “They live only a few miles from Blackwater, in a village down toward Eastbourne. Sam works out of a shed behind his mother’s house. The guard Simpson is another matter. He has taken some time off to give attention to a cousin who has returned to the family after many years in America. But he should not be too hard to look up.” “I am most appreciative, Warden Hobbs,” Holmes replied with a slight bow. “With your permission, I will look around the cell a bit.” “Be my guest, Mr. Holmes. This is a quite an emergency, is it not?” I nodded in agreement as Holmes went to the window and pulled back the dingy curtain, and there, as we had expected, was the escape route. One bar in the window was securely in its place. The other bar was separated from the

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bottom of the window and bent out at a severe angle. A small man could now fit through with little difficulty. “Watson, look at this!” Holmes exclaimed. He was pointing out to the broken bar at the point of the separation. “Observe that the broken end of this steel bar draws to a narrow point. And at the windowsill, note that the bar is completely gone. The intact bar on the left seems roughened and thickened. Hello! What have we here?” To achieve greater illumination, Holmes swung the light bulb by its suspended cord that hung from the ceiling over so the bulb was just touching the bars. Then he whipped out his glass and peered closely at the window sill itself, where I could clearly see a dark stained trough a couple of inches deep, around and between the base of the bars. The single trough extended along a length that included the base of both bars so it was as if the bottom of the two bars were placed in a shallow stone container. However, the warden assured me that the solid bars continued down into the stone beneath for at least another three feet. Holmes sniffed the air as before and drew out his pocketknife. “Look at this reddish brown liquid film in the trough, Watson, and the same at the base of the intact bar.” He scraped the intact bar with his knife. “What do you make of it?” “Why it looks like tea—the liquid and the particles. Does it mean something? Do you suppose Mouse somehow used the tea to dissolve the prison bars?” Holmes did not reply but turned and gazed slowly around the cell. He went over to the bookshelf and flipped through each of the aforementioned volumes. Finally he focused his attention on the bed and abruptly turned over the mattress. To my astonishment, there lay before our eyes a brass spoon. Undoubtedly the very spoon that the prisoner’s mother had brought some months prior. Curiously, the spoon appeared to be terribly worn and abused, rough and flattened on one side and sharpened as in a knife on the other. At times like this in an investigation, I was accustomed to leaving Holmes to his thoughts. Warden Hobbs and I watched silently as Holmes examined the spoon with his glass. Finally, he turned toward us. “May I use your office for an hour or two, Warden Hobbs? This is surely a three-pipe problem. I shall need some time alone to sort out the complexities.” “Indeed you may, Mr. Holmes.” Hobbs offered. “Dr. Watson and I might have some tea in the library. Shall we, Dr. Watson?” “A capital idea,” I said with as much enthusiasm as I could exhibit. I tried, but I could not relax under the circumstances. Holmes’s life had been threatened. The cold and dreary halls of Blackwater Prison had cast a spell of imminent danger. Thereby, after showing Holmes to the privacy of his office, the Warden escorted me to the prison library for a strange afternoon repose. Not more than an hour later, Holmes burst in unceremoniously. He approached us with long strides, smoke from his briar pipe billowing behind him like some strange locomotive. He was carrying a large paper bag rolled up under his arm. The bulk of the bag indicated that it contained some material from the prison, which Holmes must have acquired during his absence. “Watson,” he cried, “we must return at once to my cottage!” Then, to the Warden, “Mr. Hobbs, you

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will hear from me in a short time by telephone. Dr. Watson and I need to perform a few chemical experiments whereupon I expect that this matter will be cleared up. I am sure that you do not mind that we must take a few items from Mouse Mathison’s cell.” “Cleared up?” The Warden replied with surprise, waving off any concern about the items Holmes had removed. “You are truly the magician, Mr. Holmes. How did Mouse escape? Do you know? And, more importantly, he must be found at once! The threat upon your own life and the likelihood of new explosions…well, I am most alarmed by the possibilities.” “Stay near your telephone, Mr. Hobbs,” Holmes ordered, as he held tightly to the bag. “Come, Watson, we have work to do.” He turned abruptly and the two of us hurried down the hall and outside to the lot where my roadster awaited us. The ride through Sussex Downs and to Holmes’s cottage was uneventful. “As you know, Watson, I have not neglected my chemical research during my retirement. In addition to my pioneering developments in bee keeping, I have recently worked on the separation of molybdenum from molybdenite and wulfenite ores and have precipitated some new complexes of molybdenum, which have the most astonishing properties. I will tell you about it sometime. In the meantime, I think you will find that a few chemical reactions await us in my cottage laboratory.” Disturbed as I was over the events at Blackwater Prison, I had no interest in Holmes’s molybdenum research. Upon entering his cottage, Holmes shed his suit coat and slipped quickly into his laboratory apron. The bench upon which his chemical work was done was situated in a small room at the back of the cottage. The room was lit cheerily by the afternoon sun, in contrast to the dark corner laboratory of 221B Baker Street, where Holmes, in so many past chemical adventures, had revealed a criminal by the prudent use of chemistry. Without hesitation Holmes emptied the contents of the bag on to the counter top. I immediately identified many of the items that we had seen in the prison cell: the tin of tea, the can of sugar, the tall vinegar bottle, the brass spoon, the medicinal bottle of hydrogen peroxide. In addition, there was a long vial, which I recognized as one of Holmes’s own containers for crime scene evidence. In this vial was a sample of the tea-like sludge, a dark brown liquid with suspended particulates. “Shall we begin, Watson? Observe carefully all that you see. For the secrets of this most interesting case will be uncovered as we proceed, analyze, and consider. Oh, by the way, while I was ruminating in the Warden’s office, I took the liberty of studying the prison’s personnel files. I found something that I know would interest you, being as you are so fascinated with the more human side of life. But that is for later. “In the meantime, good fellow, you must, as usual, witness these chemical events with care. If they go the way I

believe they will, this little adventure of the Blackwater escape will be closed. First, Watson, I take these green crystals of ferri sulphas, better known as ferrous sulphate, and dissolve them in water. I add a little potassium thiocyanate (KSCN). What do you see, Watson?” “I see nothing but a pale green solution, Holmes,” I replied. “Indeed you do, Watson. Indeed you do! Now, to this same solution I add some of the hydrogen peroxide, Sam’s gift to his brother, which I removed from Mouse’s cell.” When Holmes added the hydrogen peroxide, the original pale green solution turned a blood red! “Rather spectacular, is it not, Watson?” Holmes said with a twinkle in his eye. “Now, to the next chemical test.” Whereupon, Holmes scraped from another one of his chemical bottles a moist, brown solid and dissolved it in water, as before, to get a faint yellow solution. “This is ferri chloridium, more commonly known as ferric chloride, Watson. To this solution I will add again the KSCN.” He did so and this time, without the subsequent addition of hydrogen peroxide, the solution turned the same blood red! “Color reactions are very satisfying, Watson. Don’t you think?” “What’s the point of all this, Holmes? Are we close to solving this case?” “Patience, my friend. What have gone before are only control experiments. Here is the critical test, Watson.” At this point, Holmes took up his vial containing the dark tea-like substance. “This dark sludge is the material from the trough in the window sill of the cell. Here, I take a one-milliliter aliquot and dilute it to four milliliters with water. We now have a clear enough solution to observe any color change. I add the KSCN as before.” “No color change at all, Holmes.” I cried. “In turn, I add some of Sam’s hydrogen peroxide, and, observe, Watson. The blood red has returned, and, my good fellow, the case of the Blackwater escape is solved!” “Holmes, do you mean that you know how Mouse Mathison got out of the prison? You can prevent any further escapes?” “Yes to both questions,” he answered. “But, Holmes, we still have the problem of how to find Mouse before he can carry out his threat. You cannot have deduced his whereabouts from chemistry!” “Is that so, Watson? Yet, in a very real way, that is exactly what I have done.”

STOP Can You Solve the Mystery?


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You can solve this mystery by understanding the chemistry carried out by Sherlock Holmes and from a careful consideration of the clues provided. 1. What did Holmes learn from the chemical tests? 2. How exactly did Mouse Mathison escape from the prison cell? 3. In all likelihood, where can Mouse Mathison be found? Sherlock Holmes reveals his solution in the paragraphs that follow.

The Solution “Consider all the facts, Watson. Admittedly, there are a plethora of observations that we have made in our afternoon at Blackwater Prison. But when we sort through these facts and observations, they collectively point in one distinct direction.” “I noticed the brass spoon, Holmes,” I offered. “Mouse had hidden it under his mattress. It was rough and worn on one side. He may have used this spoon to saw through the bar or intended it as a weapon.” “Well,” Holmes chuckled, “he may well have tried this primitive and obvious method of escape. However, Watson, consider the scale of hardness developed by the German mineralogist Friedrich Mohs. He died in 1839 but his results are still very useful to this day. Brass has a hardness of 3 to 4 on his scale, iron is 4 to 5, and steel is even higher. Brass cannot cut through steel. It is too soft. Mouse undoubtedly learned this fact and more when he finished reading his book Gems and Mineralogy. It is not surprising that Mouse scraped his knuckles in this attempt. Hence the antiseptic hydrogen peroxide that his brother Sam Mathison brought to him. Remember, we have just used that compound in these chemical tests. Mouse might also have used the spoon to try to dig the bars out from the masonry. However, he quickly would have found that the bars descend too deeply into the brick. But, Watson, what else did you notice about the spoon?” “I recall nothing of significance.” “Not even that the spoon was sharpened on one side?” Holmes inquired. “Well, I do, now that you mention it. What is the importance of that, Holmes?” “In due time, Watson,” he replied. “First, however, we must discover exactly how the bar was cut, broken, or dissolved.” “Dissolved! Would the iron of a prison bar simply disappear? I am at a loss,” I replied, slumping into a chair in his laboratory corner. “Consider, then, my good friend, the appearance of the separated bar drawn to a point. Consider the trough between and around the bars, and containing the harsh smell of vinegar and a dark red-brown liquid. Consider, also, the chemistry textbook on Mouse’s shelf and the monograph on Michael Faraday, tossed after careful study into the corner of the cell. Consider too the sharpened side of the brass spoon that was surely used as a screwdriver to remove the electric 404

wires from the bulb fixture! Consider all of these facts, Watson, and what do you have staring you in the face?” “Holmes, I—” “Electrolysis, Watson,” he cried, slamming his fist sharply on the counter top. “Electrolysis! Surely you will recall the concept from your own chemical studies in medical school. The vinegar in the trough is the electrolyte solution. Weak though it is in ionic strength, it will work (3). The electrical current is provided by the wires from a direct current source in the prison. You will recall, I am sure, that the electric bulb and the wires hang quite close to the window. The electrolysis of the steel bar could take place at night and the setup could easily be dismantled in the morning. The curtain over the window hides the progress of the resulting disintegration of the bar.” “But how can you know all this, Holmes? Is this not mere speculation at this point?” What he had said seemed possible, but how could he be so certain? It crossed my mind that a mild dementia might have afflicted Holmes in the autumn of his years. “Oh, the chemical tests tell the story, Watson. With a thin wire or powder and heat to speed up the reaction, you can dissolve some iron to produce iron 2+ ions. But would it be practical to expect the thick iron bar to dissolve in the acidic vinegar? With the assistance of electrolysis, the iron can be eaten away. The vinegar contains mostly water and some acetic acid, CH3COOH, and it provides the acidic electrolyte solution. Acetic acid is a weak acid, which is to say that some CH 3 COOH molecules break apart into CH3COO– and H+. You will appreciate that, as H+ ions are converted to H2, then more CH3COO– and H+ are formed from CH3COOH. The acetate ions are then involved in precipitation products. Here are the equations for the electrolysis of iron.” In the manner of past chemical cases, Holmes jotted something in his notebook and tossed it over to me in the chair. I examined these equations written in his familiar handwriting.



“You will appreciate that the positive wire from the bulb fixture if attached each night to the same steel bar creates a positive electrode. This metal anode causes oxidation to occur and iron atoms are converted to iron ions. Iron atoms thus leave the bar and go into the vinegar solution. The other wire is negative and provides a source of electrons to bring about the reductive production of hydrogen gas from the acidic H+ ions from the acetic acid in the vinegar. This reduction occurs at the negative cathode. Fresh vinegar can be added as needed. “So the bar is slowly eaten away by electrolysis,” I offered. “Exactly, and now you can appreciate the chemical tests, Watson. Iron(III), that is the Fe3+ ion, forms a blood red complex when treated with potassium thiocyanate, KSCN. However, iron(II), that is the Fe2+ ion, does not. However, iron(II) is quickly oxidized to iron(III) by hydrogen peroxide according to this equation.” Holmes wrote in his notebook. “The so oxidized solution will then, of course, give the blood red color with KSCN (4).” Holmes scribbled another equation in his notebook (5). “Recall that I previously demonstrated these facts before your very eyes with the ferrous and ferric compounds. And recall that the same test on the diluted material from Mouse Mathison’s window trough indicated the presence of iron(II) ions, the electrolysis product.”

“Can you detect the other electrolysis product, the hydrogen H2?” “Gone. Into the air. Whisked away in the June breezes,” said Holmes. “And there is undoubtedly some iron forming on the bar as iron ions precipitate out and thicken the negative cathodic bar. You recall how we observed that it was enlarged around its base. And the tea-like substance with the reddish residue in the trough is undoubtedly due to the presence of iron and acetate ions as well as other possible ironcontaining electrolysis products.” “I am still skeptical, Holmes,” I said from my corner chair. “The bars of Mouse’s cell are rather formidable. Could such an electrolysis really work?” “Let me have my notebook back for a moment, good fellow. Let us assume a current flow of one ampere for one hour, that is 3600 seconds. An ampere is a coulomb per second and 96,485 Coulombs constitute a mole of electrons. Are you following this, Watson? Two moles of electrons are required to remove one mole or 55.8 g of iron by electrolysis. We arrange these factors so that all the units cancel, and, presto, about one gram of iron is removed from the prison bar per hour.”

“Is this not a trivial amount, Holmes? After all, the window bar in the cell was much more substantial.” “Yes, Watson, of course,” he countered. “But running this electrolysis for eight hours a night over even thirty days would removed 240 grams of iron or about a half a pound. More than enough to succeed, I should say. You can do the arithmetic on that, I am sure. And less time would be required if the amperage is greater than our assumed one ampere.” “So the cell bars formed electrodes where the chemistry took place,” I said. “Correct,” said Holmes as he made a sketch in his notebook and handed it to me.

“On the right is the anode where oxidation took place and iron changed to iron ions. On the left is the cathode where reduction took place and hydrogen gas was produced along with some build up of iron at the surface from ions in solution. The vinegar filled the shallow trough between the bars to provide an electrolytic solution.” “I see it now, Holmes. I see how Mouse escaped. It is ingenious. But truly, the case is far from solved. Mouse Mathison must be captured!” I leaned forward in the chair and rubbed my eyes. I had seen enough chemical equations and calculations for the day, and, truth be told, with Mathison still at large, I was anguishing at the threat that hung over Holmes. Calmly, Holmes put his hand on my shoulder. “Steady Watson. In a minute or two, I shall call the Warden of Blackwater Prison on the telephone. As I told you before, in all probability, I know where Mouse Mathison is at this very moment.” “Holmes,” I cried with some emotion. “If only that were so!” “It is so, Watson. Think with me now. Consider that neither the sugar nor the tea that his mother brought nor the hydrogen peroxide from his brother form ions in water. The acetic acid in vinegar was the only electrolyte available to Mouse. The book on Michael Faraday’s work was also available, containing information on electrolysis. The electrolysis setup had to be arranged during the nighttime hours and remain undetected. All these facts point to the guard. I suspected Brun M. Simpson even before I made my little sojourn to the Warden’s office.” “The guard, Holmes, but what is his motive?” I could see, however, why Holmes might have been suspicious of him.


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“Well,” he replied with a sly smile, “You remember that I told you that I had the occasion to examine the personnel files of the prison? What would you think, Watson, if I told you that Brun M. Simpson’s middle name is Mathison! HaHaa!” Holmes clapped his hands together with self-delight. “The two of them are related. Undoubtedly, Mouse Mathison himself is the long-lost cousin from America that is keeping Mr. Simpson at home these days. That is where Mr. Mouse Mathison is right now, Watson. You can count on it. Would you be so kind as to hand me the telephone?” The call was made and the matter of the Blackwater escape was put to rest. Later that same day we received a return call from Warden Gruner Hobbs informing us that both Mouse Mathison and Brun Mathison Simpson had been taken into custody. Late in the evening, Holmes and I sat together smoking our beloved briars and each nursing a brandy, like old times, the wonderful old times. There was still a matter that puzzled me. “Holmes, the sugar and the tea that you took from Mouse’s cell. Were those needed for any analyses?” “My fee, Watson,” he replied with a laugh. “My only fee for an afternoon’s work. I thought that Mr. Mathison deserved to pay me something for my trouble. He will surely miss the tea and sugar, don’t you think? I imagine his new cell will be quite barren.” “Holmes, you seem not affected by age. Surely you are not as agile and swift as before. You seem so happy with your bees and your chemical scholarship. I cannot keep from the melancholia, myself. Our time together has been so short.” “Cheer up, my friend. The future may hold more chemical adventures for the two of us to solve. Recall the words of Marcus Aurelius (6), a stoic philosopher and one of the better emperors of ancient Rome.” …the soul, the seat of fear and pain, has full power to form an opinion about these things and need suffer nothing, unless at times it deviates into such an opinion. The mind in itself wants nothing, unless it creates a want for itself; therefore it is both free from perturbation and unimpeded, if it does not perturb and impede itself.

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Safety Note Do not try this activity with household or lab electric current. A small 9-V battery or low amperage dc power supply can be used with steel nails and vinegar to demonstrate the electrolysis of iron described in this story. Attach positive and negative leads to two nails and place in a beaker with vinegar. You can test for iron ions as described in the story. Note 1. Thomas Alva Edison developed the first direct current (dc) electric generating station in New York in 1882. George Westinghouse’s company obtained the contract to develop an alternating current (ac) generating station at Niagara Falls in 1893. Eventually the ac approach won out over dc. Today power generation and distribution systems are universally based on alternating current. For the purpose of this story a dc system was the most convenient to consider.

Literature Cited 1. Waddell, T. G.; Rybolt, T. R. J. Chem. Educ. 1989, 66, 981– 982; 1990, 67, 1006–1008; 1991, 68, 1023–1024; 1992, 69, 999–1001; 1993, 70, 1003–1005; 1994, 71, 1049–1051; 1996, 73, 1157–1159; 1998, 75, 484–486; 2000, 77, 471– 474; 2001, 78, 470–474. 2. Rybolt, T. R.; Waddell, T. G. J. Chem. Educ. 1995, 72, 1090– 1092; 1999, 76, 489–493; 2002, 79, 448–453. 3. Reese, M. K. Chem. Eng. News 2001, 79 (Apr 30), 64. An attempted escape from Swaleside Prison on the Isle of Sheppey, Kent, by using electrolysis to eat through a bar was reported in a U.K. newspaper story that was sent to Chem. Eng. News by Richard N. Zare of Stanford, CA. 4. Sorum, C. H. Introduction to Semimicro Qualitative Analysis, 3rd ed.; Prentice-Hall: Englewood Cliffs, NJ, 1960; p 133–134. 5. The red complex in water can best be written as Fe(NCS)n3–n (n = 1 or 2). See, for example, Funahashi, S.; Ishihana, K.; Tanaka, M. Inorg. Chem. 1983, 22, 2070–2073. 6. Marcus Aurelius. Marcus Aurelius and His Times, trans. G. Long; W. J. Black: Roslyn, NY, 1945; p 70.


The Chemical Adventures of Sherlock Holmes: The Blackwater Escape

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