The Chemical Adventures of Sherlock Holmes A Christmas Story

Thomas G. Waddell and Thomas R. Rybolt University of Tennessee at Chattanooga, Chattanooga. TN 37403

The following Christmas story provides a problemin qualitative chemical analysis, presented in mystery form in the context of the popular and beloved characters Sherlock Holmes and Dr. Wat-

There is a hreakin the story where the reader (students and teachers) can ponder and solve the mystery. Sherlock Halmes delivers his solution in the paragraphs following this break.

The Story

I rememberfondly nlcepinfilnteon that Christmas mom- inn near the turn of the century. Fresh snow had fallen the night before and Holmes and I had stayed up past midnight by the fire, smoking our briars, and recalling the many adventures and dilemmas which other Decembers had brought our way. Overcome by a sense of peace and well- being, I slept long and awoke to the sound of carriages muffled by the deep snow and a few cheerful voices ofpeople hurrying along Baker Street beneath my window. The air was cold and the sky was a tone of clear blue seldom seen in the Great Citv. 1 ~u l l ed mv dressinz gown around me. " . . . ., selected a favorite pipe, and went out to the living quarters of 221B to share Christmas with mv friend and colleaeue - Mr. Sherlock Holmes.

Holmes was in his chair by the crackling fire, humming some tune that sounded operatic, and concentrating the rest of his energy on repairing the fmish on his precious violin. For several weeks he had beeuso engaged, wmplain- ing of difficulties he had enwuntered in producing a certain quality color-tone in the varnish, and ignoring my urgings and pleas to attend the new play that had opened at Covent Garden.

"Holmes!" I cried. "What a morning!" But I could tell that progress on his violin had stalled and, since no new case occupied his thoughts, he was in one of his sullen moods, totally unacceptable in my mind, even for Holmes, on a morning like this.

Holmes did not speak to me, and, when Mrs. Hudson knocked on our door and entered carrying a gift, wrapped smartly in bright red paper, Holmes raised only an eyebrow.

"A gift for you, Watson, from an admirer no doubt", he said.

"No, Mr. Holmes", Mrs. Hudson shook her head. "It's for you! I found it on the step this morning, 'Mr. Sherlock Holmes, Merry Christmas'the tag says."

Holmes put the violin down and took the package fmm the outstretched arms of our fsithful landlady. Since I had been associated with him, only on the most rare occasions had Holmes ever received a gift of any kind, and indeed, he reacted with concern and a grim look of suspicion. He set the red package before him on the floor, glanced a t the tag, and with utmost care untied the ribbon and slipped off the wrapping paper. All this was done without agitating the giR, as it sat before us now in a plain brown box the size of an ale mug.

'Waddell, T. G.; Rybolt, T. R. J. Chem. Educ. 1989, 66,981. 'Waddell, T. G.; Rybolt T. R. J. Chem. Ed=. 1990, 67, 1007.

A bead of sweat mlled down Holmes'long forehead as he removed from the box a clear unlabeled jar containing a dry white solid.

"Watson", he looked up at me, "recall the names of our most recent foes."

"Holmes", I replied, " this is only a gift. It is Christmas, my good fellow. Someone has honored you with a token of their esteem."

"Names, Watson", he sternly countered snapping his fingers impatiently. 'The unusual angle and unevenness of the tag's lettering is not characteristic of a natural hand- writing. It is clear the person who is the source of this gift is attempting to disguise his true identity. Who might benefit by revenge served up to us in the season of cheer?"

"Well, Holmes, there's always Moriarty. But its seems to me that Porlanto the embezzler, Gladson the poisoner, or Kilburn, the one who murdered his stepchildren, are more likely suspects at this time."

"Capital!" Holmes rubbed his hands together and carried the iar to his chemical research table in the darkened corner of our flat. As Mrs. Hudson and I celebrated Christ- mas Dav alone with a masted eoose and three varieties of her famous pies, Holmes work;ed feverishly. We heard an occasional grunt or exclamation from the comer accompa- nied by the accustomed clank of glassware and shuffling of equipment. At 10:30 Christmas night, Holmes reappeared. I expected a look of triumph, since on other occasions, Holmes' chemical researches always led to startling reve- lations. This time, however, a look of confusion shadowed his hawklike features.

"The substance is easily puritied by sublimation, Watson. It is heat stable and definitely not an explosive. Moreover, I waxed our little mouse friend from his hole by laying out some ham covered with the material. He devoured it, Wat- son, and I observed him scampering about all day, with no ill effects. Thus, it is not a toxin or a drug either! If this is an act of revenge, does the perpetrator expect me to sprin- kle his poison into my own porridge? There are dark waters here. Watson. sinister anddark waters."

"1t;s a giR, ~o lmes ! Accept it as such", I said, showing my impatience for his annoying lack of Christmas spirit.

Sherlock Holmes turned and paced, ignoring my appeal. "I have measured a melting point of 118-120 "Celsius and i t turns litmus from blue to red. It is decidedly a carbon compound, but of what type and of what purpose is not clear. However, I can say with a great deal of confidence that i t contains 68.8% carbon and 4.9% hydrogen by weight."

I reolied gentlv. "There is an hour of Christmas left. Join Mrs. ~ u d s o n an2 me in a celebration of this holy season." I felt the same kindness toward him that I alwavs had. But Holmes is always Holmes, thank God. "In du; time, my friend, in due t i e " , he said "I have one more observation to make and I will have part of this mystery solved."

He disa~oeared again. and this time Mrs. Hudson and I waited bGhc hearth. ~hcs to le littlesad glances at meover the rimsofherrrlassesand I, inan ever-swellinr!Christmas spirit, was becoming more amused as time and as I

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reflected on the character of the World's Greatest Consult- was a delightful Christmas and tomorrow I shall start anew ing Detective. on my violin finish."

Without a sound, Holmes appeared behind my chair. "But what were the bubbles of gas?" I asked. "A water insoluble organic compound, soluble in alkali", Holmes shwk his head back and forth and said, 'Your

he somberly stated. After making this strange announce- knowledge of chemistry leaves much to be desired. Carbon ment he strode arroeantlv to the window and looked out dioxide. of course. Acharacteristic test for a carboxvlic acid. over Baker Street an2 thegas lamps glowing under caps of The addition of a carboxylic acid such as benzoi; acid to snow. He stared into the night for what seemed an endless bicarbonate of sodium releases carbon dioxide gas. Mv time, but when he fmally moved, I pulled out my pocket watch and found only ten minutes had passed.

He strode to the dusty corner of the room and returned a moment later with a flask in his left hand and a spatula containing a small quantity of the mysterious carbon com- pound in his right hand. "If my suspicions are correct, the addition of this compound should result in the evolution of gas from this solution of bicarbonate of sodium. He poured the white powder into the colorless liquid in the flask. As he swirled the flask, he looked directly a t me.

Stop Here and Solve the Mystery This mystery can be solved by applying chemical princi-

ples and deductions. Can you answer these questions?

(1) What organic compound was given to Holmes? (2) Who eave the comoaund to Holmes? I3 For u hat purpose urns the compound given? The following

para~~aphi amtmn Holmes'~ chemlcal svluuun ur the mystery. Compare your solution to his.

The Solution Mrs. Hudson and I remained seated. mesmerized bv the

tiny bubbles rising in the flask. Suddenly he turned and pointed a long white fmger. "You,

Watson, yon!" he shouted. 'You are the perpetrator!" Mrs. Hudsongasped with horror. "Mr. Holmes!" she cried.

"Have pity a t Christmas time. Have you lost all reason?" Holmes's eves were mere slits andhis brow was furrowed

and he kept pointing a t me. Unlike Mrs. Hudson, I was not shocked. I was, on the contrary, quite overcome with laugh- ter. As I was so engaged, Holmes stomped around the flat howling with unrelentina frustration. But after a few min- utes h e began to calm down as I knew be would, and he approached us sheepishly. After another minute or two he chuckled like the gentle old friend he was.

"Ah, Watson. When I discovered that the Christmas sub- stance was neither an explosive nor a poison, the mystery took on a new slant. Was revenge the motive? If so, how? If not, what was the purpose of the white substance? Its identification was then crucial, and, fortunately, a trivial matter of standard qualitative organic analysis.

"The substance is clearly benzoic acid, Watson. You knew it as well as I do now. How vour usual oDen countenance hid your involvement is truly amazing to me."

"Well. Holmes". I smiled. "With vow tirade I hardlv had a chance to stop you and before t<at, well, I . . ."

"You took me in, Watson." My friend shook his head and his eyes sparkled. "You are victorious a t my own game so to speak."

"Well, I must say, Holmes, things did not go as I had expected. I anticipated vou would turn aside from these

earlier litmus test showed I was dealing with an acid anh the oreanic com~ound's insolubilitv in water and solubilitv in alkkine poiked in tbis directi"on. Only a few types df organic compounds have such characteristics. But I had to besure before I accused you of perpetrating this hoax. You did continue to insist i t was a gift, and only the giver of a giR could know that fnrcertnin<o 1 finiilly h;gnn suspert you." 'Well, what of the long minute6 stnrinr: out the win- dow," I said. "In what projectwere you engaged during that time?" "Proportions, my dear fellow", he said.

"What?" 'You see, Watson, we have two simple laws provided for

us by the Frenchman, John Proust, and the Englishman, John Dalton. Proust gave us the law of definite proportion and Dalton the law of multiple proportion. The first law tells us that a compound contains the same proportion of elements by weight. The second law tells us that the ratios of these weights may he converted to simple whole numbers based upon the atomic weights."

"l'm afraid I still don't see, Holmes." "Consider the specific case. If carbon is 12 times the

weight of hydrogen, then it is a simple matter to deduce that 68.8 divided by12 is 5.73 and 4.9 divided by one, of course, remains 4.9. Then 5.73 divided by 4.9 is 1.17, but the key question is what simple whole number ratio gives this same ratio. As I examined the possibilities, i t was clear that 7 divided by 6 gives the same ratio of 1.17. So the law of multiple proportion tells us that the compound contains seven carbons for everv six hvdroeens." " -

"But the time", I said. "As I stared into the nieht". Holmes interiected. "1 consid-

ered a number of poss~bilities and it bkame'clear the remainine26.3 % of the weight could be made un ofoxveen. " ~. Oxygen has a weight of 16'iimc.i that of hvdr&n so 26.3 divided by 16gives 1.64and4.9 divided by l.Mgivesa ratio o f :< " .. ..

"So there must be three hvdroeens for everv one oxveen". " - " - . I said with a smile.

"Exactlv. rieht!" he replied. " ~ n d benzoic acid is a com- pound with seven carbons, six hydrogens, and two oxygens. Reallv, it's elementaw. mv dear Watson. elementarvmath."

M ~ S . Hudson had- haidly recovered from her confused state. "But if Dr. Watson sent vou that chemical. Mr. Holmes, for Heaven's sake why? &d why all the mystery? Why did he not sien the giR?"

~ b l m e s happily'filled Lis pipe with shag tobacco. "Ben- zoic acid can be used as a background for violin varnish, Mrs. H u d ~ o n . ~ . ~ Afact Dr. Watson no doubt obtained from one of London's few Italian violin makers. Dr. Watson, despite his jealousy over the attention my instrument has gotten lately, has given a aenuine gift. Watson. vou have

chemical endeavois e a r k r a n d I could announce to you the ;he true spiht of ~hristmas!" -

true ~dentitv and v u r ~ o w of the mviiterinui; comvound. In "You do zive me too much credit, Ilolmrs". I stammered. that regard;l am afraid your persisience exceeded evenmy "On the &ntrary, my good fellow! Look! 12s two minutes expectations. I did not mean to waste your entire Christ- to midnight. Amoment left. Merry Christmas, Mrs. Hud- mas day on this chemical analysis. son! Merry Christmas, Watson."

"Waste of time?" said Holmes. "Mv dear fellow the use of one's mind is never a waste of time; No, now that I reflect upon it calmly, i t made the gift all the more enjoyable. What 3Kingzen's ChemicalEncyclopedia, 7th ed.; R. K. Strong, ed.; Van better way to spend one's time than in the pursuit of truth Nostrand. NY, 1946, p 461.

4W. Thomasson, violin maker, Chattanooga, TN, personal commu- through the use of deduction and the scientific method. I t nication,

1024 Journal of Chemical Education