Emmanuel Rubin would have fought to the death rather than admit that the smile on his face was a fatuous one. It was, though. Try as he might, he could not conceal the pride in his voice or the pleased gleam in his eye.

"Fellow Widowers," he said, "now that even Tom Trumbull is here, let me introduce my guest of the evening. This is my nephew, Horace Rubin, eldest son of my younger brother and the shining light of the new generation."

Horace smiled weakly at this. He was a full head taller than his uncle and a bit thinner. He had dark, crisply curled hair, a prominent, well-beaked nose, and a wide mouth. He was definitely not handsome and Mario Gonzalo, the artist of the Black Widowers, was fighting hard not to exaggerate the features. Photographic accuracy was caricature enough. What didn't get into the drawing, of course, was the unmistakable light of quick intelligence in the young man's eyes.

"My nephew," said Rubin, "is working toward his Ph.D. at Columbia. In chemistry. And he's doing it now, Jim, not in 1900 as you did."

James Drake, the only Black Widower with a legitimate doctorate (although all were entitled to be addressed as "Doctor" by the club rules), said, "Good for him - and my own degree was earned just before the war; World War II, that is." He smiled reminiscently through the thin column of smoke curling upward from his cigarette.

Thomas Trumbull, who had, as usual, arrived at the preprandial cocktail hour late, scowled over his drink and said, "Am I dreaming, Manny, or is it customary to elicit these details during the grilling session after dinner? Why are you jumping the gun?" He waved his hand petulantly at the cigarette smoke, and stepped away from Drake in a marked manner.

"Just laying the foundation," said Rubin indignantly. "What I expect you to grill Horace about is the subject of his coming dissertation. There's no reason the Black Widowers can't gain a little education."

Gonzalo said, "Are you going to make us laugh, Manny, by telling us you understand what your nephew is doing in his laboratory?"

Rubin's scanty beard bristled. "I understand a lot more about chemistry than you think."

"You're bound to, because I think you understand zero." Gonzalo turned to Roger Halsted and said, "I happen to know that Manny majored in Babylonian pottery at some correspondence college."

"Not true," said Rubin, "but still a step above your major in beer and pretzels."

Geoffrey Avalon, who listened with disdain to this exchange, detached his attention, and said to the young student, "How old are you, Mr. Rubin?"

"You'd better call me Horace," said the young man, in an unexpected baritone, "or Uncle Manny will answer and I'll never get a word in edgewise."

Avalon smiled grimly. "He is indeed our conversational monopolist when we allow him to be. But how old are you, Horace?"

"Twenty-two, sir."

"Isn't that rather on the young side for a doctoral candidate, or are you just beginning?"

"No. I should be starting my dissertation about now and I expect to be through in half a year. I'm rather young, but not unusually so. Robert Woodward got his Ph.D. in chemistry when he was twenty. Of course, he nearly got kicked out of school at seventeen."

"Twenty-two isn't bad, though."

"I'll be twenty-three next month. I'll be getting it at that age - or never." He shrugged and looked despondent.

The soft voice of Henry, the perennial and irreplaceable waiter at all the Black Widower banquets, made itself heard. "Gentlemen, dinner is served. We are going to have curried lamb and our chef, I'm afraid, believes that curry was made to be tasted, so if any of you would prefer something rather on the blander side, tell me now and I will see to it that you are obliged."

Halsted said, "If any faint-heart would rather have scrambled eggs, Henry, just bring me his helping of curried lamb in addition to my own. We must not waste it."

"Nor must we contribute to your overweight problem, Roger," growled Trumbull. "We'll all have the curry, Henry, and bring in the accompanying condiments, especially the chutney and coconut. I intend to be heavy-handed myself."

"And keep the bicarbonate handy, too, Henry," said Gonzalo. "Tom's eyes are more optimistic than his stomach lining is."

Henry was serving the brandy when Rubin clattered his spoon against the water glass and said, "To business, gentlemen, to business. My nephew, I have observed, has wreaked havoc on the comestibles and it is time that he be made to pay for that in the grilling session. - Jim, you'd be the natural grill-master, since you're a chemist of sorts yourself, but I don't want you and Horace to get into a private discussion of chemical minutiae. Roger, you're a mere mathematician, which puts you sufficiently off the mark. Would you do the honors?"

"Gladly," said Halsted, sipping gently at his curaçao. "Young Rubin - or Horace, if you prefer - how do you justify your existence?"

Horace said, "Once I get my degree and find myself a position on a decent faculty, I'm sure that the work I do will be ample justification. Otherwise  - " He shrugged.

"You seem doubtful, young man. Do you expect to have trouble finding a job?"

"It's not something one can be certain about, sir, but I've been interviewed here and there, and, if all goes well, it seems to me that something desirable should solidify."

"If all goes well, you say. Is there some hitch in your research?"

"No, not at all. I had enough good sense to pick a fail-safe problem. Yes, no, or maybe - any of the three possible answers - would earn me a degree. As it happens, the answer is yes, which is the best of the alternatives, and I consider myself set."

Drake said suddenly, "Whom are you working for, Horace?"

"Dr. Kendall, sir."

"The kinetics man?"

"Yes, sir. I'm working on the kinetics of DNA replication. It's not something to which physical chemical techniques have hitherto been rigorously applied, and I am now able to build computerized graphics of the process, which  - "

Halsted interrupted. "We'll get to that, Horace. Later. For now, I'm still trying to find out what's bugging you. You have the prospect of a job. Your research has gone well. What about your coursework?"

"Never any problem there. Except  - "

Halsted endured the pause for a moment, then said, "Except what?"

"I wasn't that good in my lab courses. Especially organic lab. I'm not ... deft. I'm a theoretician."

"Did you fail?"

"No, of course not. I just didn't cover myself with glory."

"Well, then, what is bugging you? During dinner I overheard you tell Jeff that you'd be getting your Ph.D. when you're twenty-three - or never. Why never? Where does that possibility come in?

The young man hesitated. "It's not the sort of thing  - "

Rubin, clearly flustered, frowned and said, "Horace, you've never told me you were having problems."

Horace looked about as though searching for some hole through which he could crawl. "Well, Uncle Manny, you've got your troubles and you don't come to me with them. I'll fight this out on my own - or not."

"Fight what out?" said Rubin, his voice growing louder.

"It's not the sort of thing  - " began Horace again.

"Number one," said Rubin vigorously, "anything you say here is completely, totally confidential. Number two, I told you that at the grilling session you would be expected to answer all questions. Number three, if you don't stop playing games, I'll kick your behind into raspberry gelatin."

Horace sighed. "Yes, Uncle Manny. - I just want to say," he looked about the table, "that he's threatened me like this since I was two and he's never laid a hand on me. My mother would take him apart if he did."

"There's always a first time, and I'm not afraid of your mother. I can handle her," said Rubin.

"Yes, Uncle Manny. - All right, then. My problem is Professor Richard Youngerlea."

"Uh-oh," said Drake softly.

"Do you know him, Dr. Drake?"

"Well, yes."

"Is he a friend of yours?"

"Well, no. He's a good chemist but, as a matter of fact, I despise him."

Horace's homely face broke into a wide smile, and he said, "Then I can speak freely?"

"You could anyway," said Drake.

"Here it is," said Horace. "I'm sure Youngerlea is going to be on my examining board. He wouldn't miss the chance and he swings enough weight to get on if he wants to."

Avalon said in his deep voice, "I take it, Horace, that you dislike him."

"Very much," said Horace in a heartfelt voice.

"And I imagine he dislikes you."

"I'm afraid so. I had my organic lab under him and, as I said, I didn't shine."

Avalon said, "I imagine a certain number of students don't shine. Does he dislike them all?"

"Well, he doesn't like them."

"I gather you suspect that he wants to be on your examining board in order to cut you down. Is that the way he reacts to every student who doesn't shine in his laboratory?"

"Well, he does seem to think that lab work is motherhood and apple pandowdy and everything that's good and noble, but no, it's not just that I didn't shine."

"Well, then," said Halsted, taking over the grilling again, "we're getting to it. I teach in a junior high school and I know all about obnoxious students. I am sure that the professor found you obnoxious. - In what way?"

Horace frowned. "I am not obnoxious. Youngerlea is. Look, he's a bully. There are always some teachers who take advantage of the fact that they are in an unassailable position. They excoriate students; they brutalize them verbally; they hold them up to ridicule. They do this although they know full well that the students are reluctant to defend themselves for fear of getting a poor mark. Who's to argue with Youngerlea if he hands out a C, or, for that matter, an F? Who's to argue with him if he expresses his very influential opinion at a faculty conference that such and such a student doesn't have what it takes to make a good chemist?"

"Did he hold you up to ridicule?" asked Halsted.

"He held everybody up to ridicule. There was one poor guy who was British, and when he referred to aluminum chloride, which is used as a catalyst in the Friedel-Crafts reaction, he referred to it as 'aluminium' chloride, with the accent on the third syllable and the first u as 'yoo' instead of 'oo.' It was just the British pronunciation, after all, but Youngerlea chewed him out. He denounced all this crap - his expression - of having an unnecessary extra syllable, five instead of four, and so on, and the stupidity of making any chemical name longer than necessary, and so on. It was nothing and yet he humiliated the poor man, who didn't dare say a word in his own defense. And all the damned sycophants in the class laughed."

"So what makes you worse than the rest?"

Horace flushed, but there was a note of pride in his voice as he replied. "I answer back. When he starts on me, I don't just sit there and take it. In fact, I interrupted him in this aluminum-aluminium business. I said in a good, loud voice, 'The name of an element is a human convention, professor, and not a law of nature.' That stopped him, but he did say in his sneering way, 'Ah, Rubin, been dropping any beakers lately?' "

"And the class laughed, I suppose?" said Halsted.

"Sure they did, the pimple-heads. I dropped one beaker all course. One! And that was only because someone jostled me. - And then, once, I came across Youngerlea in the chem library looking up some compound in Beilstein  - "

Gonzalo asked, "What's Beilstein?"

"It's a reference book of about seventy-five volumes, listing many thousands of organic compounds, with references to the work done on each, all of them listed in order according to some logical but very complicated system. Youngerlea had a couple of volumes on his desk and was leafing through first one, then the other. I was curious, and asked him what compound he was searching for. He told me and I was overcome with ecstasy when I realized he was looking in the wrong volumes altogether. I moved quietly to the Beilstein shelves, took down a volume, found the compound Youngerlea wanted - it took me thirty seconds - came back to his table, and put the volume in front of him, open to the correct page."

"I suppose he didn't thank you," said Drake.

"No, he didn't," said Horace, "but at that, he might have if I didn't have the world's biggest grin on my face. At the moment, though, I would rather have had my revenge than my Ph.D. - And that may be the way it will work out."

Rubin said, "I've never considered you the most tactful person in the world, Horace."

"No, Uncle Manny," said Horace sadly, "my mother says I take after you - but she only says that when she's really annoyed with me."

Even Avalon laughed at that, and Rubin muttered something under his breath.

Gonzalo said, "Well, what can he do to you? If your marks are all right, and your research is all right, and you do all right on the exam, they've got to pass you."

"It's not that easy, sir," said Horace. "In the first place, it's an oral exam and the pressures are intense. A guy like Youngerlea is a past master at intensifying the pressure, and he can just possibly reduce me to incoherence, or get me into a furious slanging match with him. Either way he can maintain I don't have the emotional stability to make a good chemist. He's a powerful figure in the department and he might swing the committee. Even if I pass and get my degree, he has enough influence in chemical circles to blackball me in some very important places."

There was silence around the table.

Drake said, "What are you going to do?"

"Well ... I tried to make peace with the old bastard. I thought about it and thought about it, and finally asked for an appointment so that I could eat a little crow. I said I knew we had not gotten along, but that I hoped he didn't think I would make a bad chemist - that really, chemistry was my life - well, you know what I mean."

Drake nodded. "What did he say?"

"He enjoyed himself. He had me where he wanted me. He did his best to make me crawl; told me I was a wise guy with an ungovernable temper, and a few other things designed to make me go out of control. I held on, though, and said, 'But, granted I've got my peculiarities, would you say that necessarily makes me a bad chemist?'

"And he said, 'Well, let's see if you're a good chemist. I'm thinking of the name of a unique chemical element. You tell me what the element is, and why it's unique, and why I should think of it, and I'll admit you're a good chemist.'

"I said, 'But what would that have to do with my being a good chemist?' He said, 'The fact that you don't see that is a point against you. You ought to be able to reason it out, and reasoning is the prime tool of a chemist, or of any scientist. A person like you who talks about being a theoretical scientist and who therefore scorns little things like manual dexterity should have no trouble agreeing with this. Well, use your reason and tell me which element I am thinking of. You have one week from this moment; say, five P.M. next Monday; and you only have one chance. If your choice of element is wrong, there's no second guess.'

"I said, 'Professor Youngerlea, there are over a hundred elements. Are you going to give me any hints?'

" 'I already have,' he said. 'I told you it's unique, and that's all you're going to get.' And he gave me the same kind of grin I gave him at the time of the Beilstein incident."

Avalon said, "Well, young man, what happened the next Monday? Did you work out the problem?"

"It isn't next Monday yet, sir. That's coming three days from now, and I'm stuck. There's no possible way of answering. One element out of over a hundred, and the only hint is that it's unique."

Trumbull said, "Is the man honest? Granted that he is a bully and a rotter, do you suppose he is really thinking of an element and that he'll accept a right answer from you? He wouldn't declare you wrong no matter what you say, would he, and then use that as a weapon against you?"

Horace made a face. "Well, I can't read his mind, but as a scientist, he's the real thing. He's actually a great chemist and, as far as I know, he's completely ethical in his profession. What's more, his papers are marvelously well written - concise, clear. He uses no jargon, never a long word when a shorter one will do, never a complicated sentence when a simpler one will do. You have to admire him for that. So if he asks a scientific question, I think he will be honest about it."

"And you're really stuck?" asked Halsted. "Nothing comes to you."

"On the contrary, a great deal comes to me, but too much is as bad as nothing. For instance, the first thought I had was that the element had to be hydrogen. It's the simplest atom, the lightest atom, atom number one. It's the only atom that has a nucleus made of a single particle - just a proton. It's the only atom with a nucleus that contains no neutrons, and that certainly makes it unique."

Drake said, "You're talking about hydrogen-1."

"That's right," said Horace. "Hydrogen is found in nature in three varieties, or isotopes: hydrogen-1, hydrogen-2, and hydrogen-3. The nucleus of hydrogen-1 is just a proton, but hydrogen-2 has a nucleus composed of a proton and a neutron, and hydrogen-3 has one composed of a proton and two neutrons. Of course, almost all hydrogen atoms are hydrogen-1, but Youngerlea asked for an element, not an isotope, and if I say that the element hydrogen is the only one with a nucleus containing no neutrons, I'd be wrong. Just wrong."

Drake said, "It's still the lightest and simplest element."

"Sure, but that's so obvious. And there are other possibilities. Helium, which is element number two, is the most inert of all the elements. It has the lowest boiling point and doesn't freeze solid even at absolute zero. At very low temperatures, it becomes helium-II, which has properties like no other substance in the Universe."

"Does it come in different varieties?" asked Gonzalo.

"Two isotopes occur in nature, helium-3 and helium-4, but all those unique properties apply to both."

"Don't forget," said Drake, "that helium is the only element to be discovered in space before being discovered on Earth."

"I know, sir. It was discovered in the Sun. Helium can be considered unique in a number of different ways, but it's so obvious too. I don't think Youngerlea would have anything obvious in mind."

Drake said, after blowing a smoke ring and regarding it with some satisfaction, "I suppose if you're ingenious enough, you can think up something unique about each element."

"Absolutely," said Horace, "and I think I've just about done it. For instance, lithium, which is element number three, is the least dense of all the metals. Cesium, element number fifty-five, is the most active of all the stable metals. Fluorine, element number nine, is the most active of all the nonmetals. Carbon, element number six, is the basis of all organic molecules, including those that make up living tissue. It is probably the only atom capable of playing such a role, so that it is the unique element of life."

"It seems to me," said Avalon, "that an element that is uniquely related to life is unique enough  - "

"No," said Horace violently, "it's the answer least likely to be true. Youngerlea is an organic chemist, which means he deals with carbon compounds only. It would be impossibly obvious for him. Then there's mercury, element number eighty  - "

Gonzalo said, "Do you know all the elements by number?"

"I didn't before last Monday. Since then, I've been poring over the list of elements. See?" He pulled a sheet of paper from his inside jacket pocket. "This is the periodic table of elements. I've just about memorized it."

Trumbull said, "But it doesn't help, I gather."

"Not so far. As I was saying, mercury, element number eighty, has the lowest melting point of any metal, so that it is the only metal that is a liquid at ordinary temperatures. That's certainly unique."

Rubin said, "Gold is the most beautiful element, if you want to get into aesthetics, and is the most valued."

"Gold is element number seventy-nine," said Horace. "It's possible to argue, though, that it's neither the most beautiful nor the most valued. Many people would say a properly cut diamond is more beautiful than gold, and, weight for weight, it would certainly be worth more money - and a diamond is pure carbon.

"The densest metal is osmium, element number seventy-six, and the least active metal is iridium, element number seventy-seven. The highest melting metal is tungsten, element number seventy-four, and the most magnetic metal is iron, element number twenty-six. Technetium, element number forty-three, is the lightest element that has no stable isotopes. It is radioactive in all its varieties, and it is the first element to be produced in the laboratory. Uranium, element number ninety-two, is the most complicated atom to occur in substantial quantities in the Earth's crust. Iodine, element number fifty-three, is the most complicated of those elements essential to human life, while bismuth, element number eighty-three, is the most complicated element that has at least one isotope that is stable and not radioactive.

"You can go on and on and on and, as Dr. Drake said, if you're ingenious enough, you can tag each and every element with a unique characteristic. The trouble is that there's nothing to say which one Youngerlea is thinking of, which uniqueness is his uniqueness, and if I don't come up with the right something, he's going to say that that proves I don't have the capacity to think clearly."

Drake said, "If we put our minds together right now  - "

Trumbull interrupted, "Would that be legitimate? If the young man gets the answer from others  - "

"What are the rules of the game, Horace?" Avalon said. "Did Professor Youngerlea tell you that you could not consult anyone else?"

Horace shook his head emphatically. "Nothing was said about that. I've been using this periodic table. I've been using reference books. I see no reason why I can't ask other human beings. Books are just the words of human beings, words that have been frozen into print. Besides, whatever you may suggest, it's I who will have to decide whether the suggestion is good or bad, and take the risk on the basis of that decision of mine. - But will you be able to help me?"

"We might," said Drake. "If Youngerlea is an honest scientist, he wouldn't give you a problem that contains within it no possibility of reaching a solution. There must be some way of reasoning out an answer. After all, if you can't solve the problem, you could challenge him to give you the right answer. If he can't do that, or if he makes use of an obviously ridiculous path of reasoning, you could complain loudly to everyone in the school. I would."

"I'm willing to try, then. Is there anyone here, besides Dr. Drake, who is a chemist?"

Rubin said, "You don't have to be a professional chemist at the Ph.D. level to know something about the elements."

"All right, Uncle Manny," said Horace. "What's the answer, then?"

Rubin said, "Personally, I'm stuck on carbon. It's the chemical of life and, in the form of diamond, it has another type of uniqueness. Is there any other element that, in its pure form, has an unusual aspect  - "

"Allotrope it's called, Uncle."

"Don't fling your jargon at me, pip-squeak. Is there any other element that has an allotrope as unusual as diamond?"

"No. And aside from human judgments concerning its beauty and value, the diamond happens to be the hardest substance in existence, under normal conditions."

"Well, then?"

"I've already said that it's too obvious for an organic chemist to set up carbon as a solution to the problem."

"Sure," said Rubin. "He chose the obvious because he thinks you'll dismiss it because it's obvious."

"There speaks the mystery writer," grumbled Trumbull.

"Just the same, I reject that solution," said Horace. "You can advise me, any of you, but I'm the one to make the decision to accept or reject. Any other ideas?"

There was complete silence about the table.

"In that case," said Horace, "I'd better tell you one of my thoughts. I'm getting desperate, you see. Youngerlea said, 'I'm thinking of the name of a unique chemical element.' He didn't say he was thinking of the element, but of the name of the element."

"Are you sure you remember that correctly?" said Avalon. "You didn't tape the conversation, and memory can be a tricky thing."

"No, no. I remember it clearly. I'm not the least uncertain. Not the least. - So yesterday I got to thinking that it's not the physical or chemical properties of the element that count. That's just a red herring. It's the name that counts."

"Have you got a unique name?" asked Halsted.

"Unfortunately," said Horace, "the names give you as much oversupply as the properties of the elements do. If you consider an alphabetical listing of the elements, actinium, element number eighty-nine, is first on the list, and zirconium, element number forty, is the last on the list. Dysprosium, which is element number sixty-six, is the only element with a name that begins with a D. Krypton, element number thirty-six, is the only one with a name that begins with a K. Uranium, Vanadium, and Xenon, which are elements numbers ninety-two, twenty-three, and fifty-four, respectively, are the only elements to begin with a U, V, or X. How do I choose among these five? U is the only vowel, but that seems weak."

Gonzalo said, "Is there any letter that doesn't start the name of any element at all?"

"Three. There is no element that starts with J, Q or W - but what good is that? You can't claim an element is unique just because it doesn't exist. You can argue that there are an infinite number of elements that don't exist."

Drake said, "Mercury has, as an alternative name, 'quicksilver,' That starts with a Q."

"I know, but that's feeble," said Horace. "In German, I and J are not distinguished in print. The chemical symbol of iodine is I, but I've seen German papers in Latin print, in which the symbol of the element is given as J, but that's even feebler.

"Speaking of the chemical symbols, there are thirteen elements with symbols that are single letters. Almost always that letter is the initial of the name of the element. Thus, carbon has the symbol C; oxygen, O; nitrogen, N; phosphorus, P; sulfur, S; and so on. However, the element potassium has the symbol K."

"Why?" asked Gonzalo.

"Because that's the initial of the German name, Kalium. If potassium were the only case, I might consider it, but tungsten has the symbol W, for the German name, Wolfram, so neither is unique. Strontium has a name that starts with three consonants, but so do chlorine and chromium. Iodine has a name that starts with two vowels, but so do einsteinium and europium. I'm stopped at every turn."

Gonzalo said, "is there anything about the spelling of the element names that is the same in almost all of them?"

"Almost all of them end in ium."

"Really?" said Gonzalo, snapping his fingers in an agony of thought. "How about the element the British pronounce differently. They call it 'aluminium' with the ium ending, but we say 'aluminum' so that it has only a um ending, and the professor made a fuss about it. Maybe it's aluminum that's unique, then."

"A good thought," said Horace, "but there's lanthanum, molybdenum, and platinum, each with a um ending. There are also endings of ine, en, and 'on', but always more than one of each. Nothing unique. Nothing unique."

Avalon said, "And yet there must be something!"

"Then tell me what it is. Rhenium was the last stable element to be discovered in nature; promethium is the only radioactive rare earth metal; gadolinium is the only stable element to be named after a human being. Nothing works. Nothing is convincing."

Horace shook his head dolefully. "Well, it's not the end of the world. I'll go to Youngerlea with my best guess and, if that's wrong, let him do his worst. If I write a crackerjack dissertation, it may be so good they couldn't possibly flunk me, and if Youngerlea keeps me from getting a place at Cal Tech or M.I.T., I'll get in somewhere else and work my way up. I'm not going to let him stop me."

Drake nodded. "That's the right attitude, son."

Henry said softly, "Mr. Rubin?"

Rubin said, "Yes, Henry."

"I beg your pardon, sir. I was addressing your nephew, the younger Mr. Rubin."

Horace looked up. "Yes, waiter. Is there something else to order?"

"No, sir. I wonder if I might discuss the matter of the unique element."

Horace frowned, then said, "Are you a chemist, waiter?"

Gonzalo said, "He's not a chemist, but he's Henry and you had better listen to him. He's brighter than anyone in the room."

"Mr. Gonzalo," said Henry, in soft deprecation.

"It's so, Henry," insisted Gonzalo. "Go ahead. What do you have to say?"

"Only that in weighing a question that seems to have no answer, it might help to consider the person asking the question. Perhaps Professor Youngerlea has some quirk that would lead him to attach some importance to a particular uniqueness, which, to others, might be barely noticed."

"You mean," said Halsted, "uniqueness is where you find it?"

"Exactly," said Henry, "as is almost everything that allows for an element of human judgment. If we consider Professor Youngerlea, we know this about him. He uses the English language carefully and concisely. He does not use a complicated sentence when a simpler one will do, or a long word where a shorter word will do. What's more, he was furious with a student for using a perfectly acceptable name for aluminum, but a name which added a letter and a syllable. Am I correct in all this, Mr. Rubin?"

"Yes," said Horace, "I've said all that."

"Well, then, on the club's reference shelf, there is the World Almanac, which lists all the elements, and we have the Unabridged, of course, which gives the pronunciations. I've taken the liberty of studying the material during the course of the discussion that has been taking place."

"And?"

"It occurs to me that the element praseodymium, which is number fifty-nine, is uniquely designed to rouse Professor Youngerlea's ire. Praseodymium is the only name with six syllables. All other names have five syllables or less. Surely, to Professor Youngerlea, praseodymium is bound to seem unbearably long and unwieldy; the most irritating name in all the list, and unique in that respect. If he had to use that element in his work, he would probably complain loudly and at length, and there would be no mistake in the matter. Perhaps, though, he does not use the element?"

Horace's eyes were gleaming. "No, it's a rare earth element and I doubt that Youngerlea, as an organic chemist, has ever had to refer to it. That would be the only reason we haven't heard him on the subject. But you're right, Henry. Its mere existence would be a constant irritant to him. I accept that suggestion, and I'll go to him with it on Monday. If it's wrong, it's wrong. But" - and he was suddenly jubilant - "I'll bet it's right. I'll bet anything it's right."

"If it should be wrong," said Henry, "I trust you will keep your resolve to work your way through in any case."

"Don't worry, I will, but praseodymium is the answer. I know it is. - However, I wish I had gotten it on my own, Henry. You got it."

"That's a small item, sir," said Henry, smiling paternally. "You were considering names and, in a very short time, I'm sure the oddity of praseodymium would have struck you. I got to it first only because your labors had already eliminated so many false trails."

Afterword

"Unique Is Where You Find It" and the following story, "The Lucky Piece," were both written, by request, for a magazine that was to be devoted to mystery short stories. Both stories were paid for generously, and then, as sometimes happens in publishing, something went wrong and the magazine never appeared.

I therefore placed "Unique Is Where You Find It" in a collection containing both my science fiction and my science essays in alternation (thus encouraging readers to read both and, if they were only acquainted with me in one of my incarnations, to rush out and buy the other with mad abandon). "Unique Is Where You Find It" represented the only brand-new item in the book, which is entitled The Edge of Tomorrow and was published by Tor Books in 1985.

This is one of the not-so-rare cases where something in the story is based on an actual event in my life. When I was in graduate school, I had a professor much like Youngerlea, and my own reaction to him was very much like Horace Rubin's. The Beilstein incident, described in the story, really happened exactly as described and I really seized the opportunity to humiliate the professor even at the risk of damage to my grades and considered the opportunity well worth the risk.