The Amazing Dr. Darwin

THE HEART OF AHURA MAZDA

The young man in the expensive topcoat leaned casually against the tavern wall and sipped at a pint of dark ale. He was eavesdropping and trying to disguise the fact, although the three people sitting in the corner were too absorbed in their own conversation to care in the slightest if they were overheard.

They were an ill-assorted trio. The one leaning on the table was well into his sixties, and instead of a wig he wore a round fur hat to cover his domed bald head. Now and again he would illustrate a point he was making with a sharp rap of his nails on the smooth board, or a snap of fingers in the air. His energy and animation of manner suggested a man half his age.

His two companions presented a less attractive prospect. Jacob Pole was in his fifties, thin to the point of being gaunt. His sallow complexion gave him a look of slight but perpetual jaundice. He sat briskly upright, the set of his shoulders marking his long years of military service.

Erasmus Darwin was if anything even less prepossessing. He was in his early forties, but his corpulence, lack of front teeth, and jowly face marked by smallpox conspired to make him look much older. Only the eyes redeemed his coarse appearance. They were grey, patient, and sagacious, and they twinkled with appreciation of the humor of the conversation.

“She’s very intelligent,” the fur-capped man was saying, in an English accent that was hard to place. “Pretty, too. Any man would be proud to be seen with her on his arm. So think about it, Erasmus. You have been a widower too long, maybe it’s time you took another wife.”

“Easy for you to suggest—you are already married, even if your lady is living in another country.” Darwin gestured at a waitress to bring another pot of beef tea and a plate of savories. “Marriage is a large step. Answer me this, Joseph, and Jacob can be a witness. If you were free, would you honestly wish to be bonded to young Mary? I talk not of bedding her, now, I talk of marriage. Think of it, Joseph. Within a month she’d have reorganized your whole life.” The slight stammer in his speech showed that he was enjoying the banter.

“Preserve me from that. I’m on trial now, am I?” The older man glanced from one of his companions to the other. “I rely on you, Erasmus, and on you, Jacob, to let no word of this reach Mary. But at my age, a man is either organized or he will never tolerate organization. And Mary Rawlings is too young for me”—he held up a hand to forestall comment—“too young for me to marry. The years after fifty are like late-season hothouse fruit, their enjoyment must be carefully planned. We have so few of them, and they must rest on a suitable dish.” He pulled out of his waistcoat pocket a curious pair of spectacles that were divided horizontally in each lens, and used them to peer at a tiny fob watch. “No more tea for me. Five minutes, and I must be off. As for Mary, I’m too old and fragile to keep up with her young blood.”

The fat man’s grey eyes took on a new look, and he sat for a moment with his head cocked to one side. “What think you of that, Jacob?”

“You’re the doctor, ’Rasmus, but I’ll do my best.” Jacob Pole peered at the older man as though seeing him for the first time. “For my money, Joseph, I’d say that you appear unnaturally hale, hearty, and energetic.”

“Ah, but neither you nor Dr. Darwin has made an examination of me.” The fur-capped man was grinning. “If you could just see my ruined liver and poor withered body—”

“A competent physician does not need that. The evidence of health is written in your bearing and your countenance.” Darwin swivelled in his chair, so that he could take in the whole room of the tavern. “Look around you, now, and read the Book of Nature. See what is stamped in each face and body. There, by the door, side by side, we at once find goiter and rickets.”

“You need to do better than that, ’Rasmus,” Jacob Pole said gruffly. “Why, dammit, I can see that much myself.”

“Patience, both of you. We begin with the easiest. Look along the bar, now, and take the men in order. The first is again too simple: consumption, in its middle stages. The second is in good health. Take the next one, the ex-sailor in the ragged jacket with his back to us. What do you see?”

Joseph Faulkner adjusted the spectacles on his nose, and peered carefully. “Without seeing his face… Hm. At the least, we have the effects of strong drink.”

“Bravo. The half pint of gin clutched in his hand might be considered a clue, but we certainly admit the harmful effects of an indulgence in strong drink. What else?”

“Palsy?”

“No.” Darwin shook his bewigged head in satisfaction. “That is a symptom, not a cause. Regard the uncertain set of the heels on the floor, and the way that the arm moves to reach the glass. You are viewing third-stage syphilis.”

“You are sure?” Faulkner regarded the ex-sailor with a new eye.

“I am positive. He is far gone. If you could see his face, the ravages would become clear. But both of you, consider the man farther along, in the plum-colored fustian, looking this way and getting ready to leave. What of him, Colonel?”

Jacob Pole shrugged. “Ruddy face, clear eyes, a strong, square build. Thick black hair.”

“True enough. But look below the surface. Well, Joseph? What do you say?”

“He ought to be healthy as a horse. But…” Faulkner paused.

“Aha! State your but. Your instincts are sound, Joseph, but you lack the detailed knowledge to support them. My friends, we must go beyond the superficies of hair and frame, if we are to achieve valid diagnosis.” The stammer vanished from Darwin’s voice when the subject was medicine. “Look rather at the color of the lips—is there not a purple tinge to them? Look at the veins in the temples, look at the posture, look at the cheeks, with a suggestion of grey. Look at the strain in his walk. Look at the clubbed fingertips. He suffers from severe and degenerative heart disease.”

The other two men stared again as the black-haired stranger walked out of the tavern. Joseph Faulkner shook his head and took off his glasses. “Bedaddle. You are serious, are you not?”

“Completely. That man has perhaps a year to live.”

“Scampages! If I did not know you to be a recent visitor to London, I would swear those people all must be your patients.” He turned. “Unless you, Colonel Pole?…”

“Not guilty.” Pole shook his head. “I never set eyes on any one of them before.”

“Then you are lucky, Erasmus, that we live in the Age of Reason. Two centuries ago you would have surely been burned for wizardry. When you sense such quick mortality, do you not feel the urge to speak to men and women of their diseases?”

“I do. But then I ask myself, to what end? If that man were my patient in Lichfield, and wealthy, I would certainly discuss his ailment and suggest a change of style in his life. But the unfortunate who left has no such opportunities. He is poor—you saw his shoes?—with no money for medications. Better to allow him to live as happy as he may. With or without my bad news, he will be gone by year’s end.”

Faulkner stood up. “As I must be gone now. I have a meeting across the river in Southwark. Until tonight, gentlemen, at seven?”

“And the renewed pleasure of your company.” Darwin nodded, but he did not rise as their companion buttoned his heavy coat and strode out into the gloom and chill of a February fog. He poured more beef tea, for himself and Jacob Pole.

“Are you suggesting,” Pole said gloomily, “that if I were sick, you would not tell me about it?”

“You mean, if I could not help you? Then I would say nothing.” Darwin was absentmindedly eating his way through the whole tray of cheese and pork savories. “What happiness would it bring you, to know you were victim of some incurable disease?”

“Hmph. Well—”

Pole’s reply was interrupted. The young man who had been hovering by the tavern wall stepped forward to the table.

Darwin did not seem in the least surprised. He merely nodded, and said with a full mouth, “I wondered which of the three of us was the focus of your interest. I am merely surprised that it is I, since I am more of a stranger to this city.”

“I know that, sir.” The other man nodded politely to Darwin and Pole but he was clearly uneasy, shifting from foot to foot. He was bareheaded, blond, and clean shaven, with a blooming fresh-skinned face that scarce needed a razor. “But it is nonetheless you with whom I wish to speak.” He glanced again at Jacob Pole, this time unhappily.

Darwin gazed up at the earnest face. The youth was well dressed and healthy, but there was a certain stolidity of manner and dullness to his eye. “You may speak before Colonel Pole as you would before me. His discretion is absolute. It is, I assume, a medical problem that you suffer?”

“Oh, no sir.” The young man was startled. “Or at least, sir, it is, but not my own. It is the problem of a—a friend of mine.”

“Very well.” Darwin pursed his full lips and gestured to the seat vacated by Joseph Faulkner. “Help yourself to beef tea, and tell me about your friend. Tell all, root and branch. Detail is at the heart of diagnosis.”

“Yes, sir.” The man sat down. He cleared his throat. “My name is Jamie Murchison. I am from Scotland. I came here to study medicine with Doctor Warren.”

“A wise choice. The best doctor in London. You selected him as your teacher?”

“No, sir. My father chose him for me.”

“I see. But if Warren cannot help with your problem, I am convinced that I will do no better.”

“Sir, Doctor Warren’s own health has not been good. Furthermore, he says that you are his superior, especially in matters of diagnosis. But in any case, I did not consult him for other, more personal reasons. You see, the lady with the problem—”

“Lady!”

“Yes, sir.” Murchison paused uncertainly. “Is that bad?”

“No. But I owe you an apology. Nine out of ten who so begin, saying that they have a friend with a medical condition, are actually describing their own problem. I assumed it to be true in your case. Pray continue.”

“Yes, sir. The lady is Florence Trustrum. She is nineteen years old and a second cousin to Dr. Warren. I met her through him. She hails from the Isle of Man, and is now in service at the house of your friend, Mr. Faulkner. That is the other reason why I preferred to entrust this matter to you. Mr. Faulkner does not know me well. Florence and I met each other socially, four months ago. We have become good friends. Two weeks ago, she came to me and confided a strange physical symptom.”

“To wit?”

“In certain circumstances, she feels a crawling sensation on the skin of her face and arms.”

“And that is all?”

“No, sir. At the same time she feels her hair stand on end, as though she has seen a ghost.”

“Hair standing on end. For which a suitable medical term would be? Since you are a medical student, we may as well exploit that fact for the enlightenment of Colonel Pole.”

Murchison frowned and shook his head. “I don’t recall.”

“It is known as horripilation. Remember that.”

“Yes, sir. But it is not horra—horri-pil-ation, as I have read of it. Florence does not see gooseflesh, nor feel any sense of cold or terror when it happens. She says it may occur equally when she is cheerful, or relaxed, or thinking of something else entirely. And so I wondered, sir. In your great experience have you ever encountered any disease with such symptoms?”

“Never,” said Darwin promptly. He rubbed at his jaw, which was in bad need of a razor. “Have you been present when it happens? Or has anyone else?”

“Not I. She said that Mr. Faulkner was with her on one occasion, and Richard Crosse, who lodges with Mr. Faulkner, on another; but neither man saw or felt anything.”

“And the times and places?”

“The times, all different ones. The place, in her own room on the ground floor of Mr. Faulkner’s home in Saint Mary-le-Bow. I have been there myself. I felt nothing, nor did I see anything unusual.”

“But you did not think to consult your teacher, Dr. Warren.”

“I thought of it, yes. But you see, if Dr. Warren were to think that Florence were ill, he will also feel it is his responsibility to inform her parents. And they will insist that she return home at once for treatment—they do not understand what a fine doctor she has here. And if she goes to the Isle of Man, while I must stay…”

“I understand perfectly. But as to my possible role?”

“Sir, I am only a student. There are many ailments outside my experience. And Florence told me that you will be visiting Mr. Faulkner’s house tonight. You will see her. I thought, perhaps you will find a symptom in her invisible to me. If you would just take a look at her…”

“I will certainly look.” Darwin smiled ruefully. “Before my friend Colonel Pole makes the point for me, I must admit to my own weakness. Even without your adjuration, I could not help but look. Diagnosis is so ingrained in me, it is a way of life.”

“Thank you, sir.” Murchison relaxed visibly. “You see, she does not seem ill. Is there anything else that you can think of to explain her condition?”

“Nothing.” Darwin shook his head decisively. “I know no disease that provides such symptoms. But that is certainly not conclusive. In our knowledge of the human body, the best of us are no better than fumbling children. You may take comfort from this: feeling well is the best evidence I know of good health. If Florence continues to show no other symptoms than those that you describe, she should not worry. But I confess, I would certainly like to see—”

He was interrupted. An unshaven man carrying a lantern and dressed despite the cold only in dirty trousers and a thin blue shirt had come running into the inn. “Dr. Darwin!” he shouted to the room at large. “Is there a Dr. Darwin here?”

“There is.” Darwin began to stand up, groping under the table for his heavy walking stick. “Damn it, Jacob, can you get that for me? I’m not built for bending.” Then, to the man with the lantern. “I am Dr. Darwin. What do you want?”

“Emergency, sir.” The man was gasping for breath. “At the Exhibition by the Custom House. They sends me to look for you, and ask you to go there.”

Darwin looked quickly to Jamie Murchison, who shook his head. “No doing of mine, sir.”

“Then come with me. Perhaps you will have opportunity to add to your store of medical knowledge.” Darwin addressed the panting messenger. “I assume that someone at the Exhibition is ill?”

“No sir.” The ill-clad man was heading rapidly for the door, but he turned to show a somber face. “Someone is dead.”

Darwin and Murchison followed. Jacob Pole suddenly found himself alone at the table.

“Well, damn me,” he said. And then, to the whole room, “You see the way of it? They sit here, they talk and talk and eat and eat, enough for a dozen normal folk. I sit and listen.” He fished into his pocket and threw coins onto an empty platter. “Then they run and run—and guess who’s left alone at the end to pay the bill? Never trust a philosopher, my friends—he’ll pick your pocket fast as any magsman, and then explain how you’re lucky still to have your trousers.”

“Gout,” said Darwin, as they followed the lantern-bearing messenger through the fog-shrouded London streets.

The long, wan twilight of early February was near its end, and lamps were already burning in every house. It had snowed the day before, but the streets had been well cleared so that only grey mounds of slush remained. Now the yellow lamplight, bleeding out from tall, narrow windows, fell on the dull snow heaps and did more to emphasize their rounded shadows than to illuminate the pavement and road beyond.

Darwin banged his walking stick hard on the wet cobblestones. “Damnable gout, and damnable weather. Physician, heal thyself—but I have been unable to do so. I diagnose my condition, and I treat it well enough with cupping and with willow bark infusions, but I cannot cure it. Temperance helps, but this creeping cold brings it to life again. How much farther?”

“A few hundred yards.” Jamie Murchison resisted the urge to help Darwin. The other man was considerably overweight, and a little lame, but he was stumping along cheerfully and energetically. “We must walk along Eastcheap and Great Tower Street, sir, then south to the river. Half a mile at the most. Have you not visited the Exhibition yourself, Dr. Darwin? It has been the talk of London for these ten days.”

“I have not. Colonel Pole is your man for that—he plans a visit tomorrow. For my part, when someone tells of priceless jewels, and Persian demons, and Zoroastrian mysteries, I assume that it is merely an attempt to make a mumchance of the whole city.”

“But this is different, sir. The ruby is protected by a curse—and now it seems that the curse has shown its power.”

“We shall see. In a town full of calculating pigs, and dancing bears, and fire-eaters, and sword-swallowers, and purveyors of everything from Cathay aphrodisiacs to Indian opiates to French purges, anything may be claimed. For in my experience, London draws the charlatans of England, as a boil draws to it the body’s poisonous humors. Have you visited this Exhibition yourself, Mr. Murchison?”

“Yes, sir. Twice.” Murchison looked away to hide his embarrassment. “I went with Florence.”

“Then tell me what you saw. I am setting a bad example by my skepticism. In life, as in the examination of a new patient, one should keep the mind forever open for novelty of impression. Tell me all.”

“You will see it for yourself in another minute—we are almost there. But it is simple enough. Two weeks ago, the hall where the Exhibition resides was rented by a Persian, Daryush Sharani, for the purpose of displaying a magnificent ruby of vast age and religious significance. It is known as the Heart of Ahura Mazda, and it is huge—the size of a big man’s fist. But the thing that makes the Exhibition unique, and attracts so much public attention, is that although Sharani stays always with the gem, he disdains other guards. He insists that the Heart carries with it its own protection, in the form of a curse within the stone. The curse of Ahura Mazda invokes a demon, who binds and makes helpless anyone who touches the jewel. If that demon is not quickly banished by Daryush Sharani, the would-be thief will die.”

“Easy enough to say. Did anyone test the Persian’s claims?”

“They did, when the Exhibition began. With a hundred or more people watching, four men tried to take the jewel while Sharani stood by smiling. As soon as each one touched the stone, he was bound rigid until Sharani reached over the Heart of Ahura Mazda and whispered the invocation that controls the demon. Then the men were released. They looked dizzy, and in discomfort; but they moved freely enough.”

Murchison heard Darwin’s skeptical grunt. “I felt as perhaps you are feeling, sir,” he went on, “that it is easy enough to pay a poor man to stand still for a few minutes, and have him say that he was frozen by the curse. But one of the four was a nobleman, the Earl of Marbury, who is far beyond bribery and above corruption. He swore that as he tried to lift the Heart of Ahura Mazda he was seized by the demon, and unable to move a muscle until Sharani invoked the words of release. He also says that the demon’s grip is pure torment, unlike any pain that he had ever felt before.”

They had reached the hall, a rectangular building of grey limestone fifty yards from the river. The double entrance doors were iron-bound oak, open now but carrying two heavy padlocks. On the left-hand door was pinned an announcement that the Heart of Ahura Mazda would be on display from January 30th to April 25th. The right-hand door showed the admission price, of twopence per person per visit.

Within, half a dozen oil lamps lit an oblong sanded floor, in the center of which stood a large metal plate. Upon the plate was a silver pedestal, and on top of that an empty cushion of black velvet within a hemisphere of glass.

The messenger and Murchison hurried on at once toward the far wall, where a motionless human form lay surrounded by a small group of men. But Darwin stood just two steps inside the door, wrinkling his nose in perplexity and sniffing the air. It was ten more seconds before he walked forward, moving to study the pedestal and its empty cover. Finally he banged his walking stick hard on the stone floor, to produce a hollow boom that echoed around the hall. He walked forward to join the others.

The body lay supine, blue eyes open and arms thrown wide. Darwin knelt down beside it, and grunted in astonishment. The man was the black-haired stranger from the Boar’s Head Tavern.

“And who are you, sir?” asked one of the men standing by the body. He was well dressed in a heavy woollen coat, leather boots, and gaiters, and he wore clerical garb. “The magistrate has already been called.”

“I am Erasmus Darwin, a physician.” Darwin did not look up. “But I fear I can do nothing for this poor fellow. Does anyone here know him?”

“I do, sir.” It was a watchman, carrying a staff and a shielded lantern. “He’s been regular in these parts these two year, an’ often ’anging around when jewlery an’ plate goes a-missin’. But nuffin’s been proved, not near enuff for a dance at Tyburn.”

“You sent for me when you found him?”

“No, sir. Not I.”

“Then which of you did send for me?”

There was a silence. Darwin turned to the messenger, who shook his greasy head firmly. “None of these gentlemen, sir. I was given a florin in Lower Thames Street, by a man I never seed before. He said there was somebody a-dying in the Exhibition Hall, and I was to go to the Boar’s Head an’ bring Dr. Erasmus Darwin.”

“I saw this man alive, in that same tavern, less than an hour ago.” Darwin bent to grasp the man’s wrist, and to touch him on temple, mouth, and at the hollow of his neck. He loosened the fustian jacket, and made a rapid examination of chest and abdomen. Then he stood up. “He has been dead less than thirty minutes. Who found him?”

“Me it was.” The grubby watchman lifted his staff. “On me first round. I sees a window open at the back, so I come to the front an’ let meself in.” He held up a heavy bunch of keys. “With these. An’ there he was. Dead as mutton. An’ the jewel—gone.”

“He is just where you found him?”

“Yessir. I think he staggers back here, see, tryin’ to reach the winder, but ’e dies ’fore he gets to it.”

Darwin shook his head and pointed to the sanded floor. In the lantern light, a pair of wavy lines ran from the metal plate and pedestal to the wet, battered shoes of the dead man. “He was dragged this way. You are sure that no one here pulled him?”

“Positive, sir.” The clergyman spoke again. “I was passing by, and I came in straight on the watchman’s heels. When we entered the man was exactly as you see him.”

“Just as the demon left him,” said a ragged man softly. The little group of people stirred and looked nervously around the shadowed hall.

“Now then, we’ll have no blasphemies here,” said the clergyman mildly. “When a man dies, there is no need to call for demons. I’m sure the doctor can tell us the natural cause of death.”

The men around the body turned to Darwin expectantly. He hunched his shoulders, and shook his head in irritation. “The obvious diagnosis is a massive heart failure, but it is not a reply I can offer in good conscience. I saw this man earlier today, and observed him closely. He was not at the point of death. And I am sure that this was not present.”

Darwin stooped, and lifted the limp right arm of the dead man. As he turned it, an ugly heart-shaped cicatrix about an inch and a half across was revealed on the palm of the hand. The middle was white, the edge a lurid blood-red.

“The Mark of the Beast!” Everyone except Darwin and Murchison took a pace back.

“Nonsense.” The clergyman’s voice sounded less confident than his words. “It is a simple wound—a burn. Is that not so, sir?”

“It is not.” Darwin gestured at Murchison, who had sunk to his knees to study the mark more closely. “No medical student would admit such a conclusion were I to draw it. But as to what it is…” He fell silent, then looked up. “I would like a chance to examine the body more fully. I have seen nothing like this in twenty years as a physician.”

He straightened, and walked across to the pedestal. He lifted it, in spite of Jamie Murchison’s cry, “Be careful!”

“Careful of what?” Darwin peered at the empty setting of black velvet, then at the silvered sides of the pedestal. “If there is no demon who guards the Heart of Ahura Mazda, then surely I am in no danger. And if there is a demon who accompanies the ruby, since the ruby is not here, again I am safe.”

“So you truly believe that we have a—a—” The clergyman had followed Darwin, but he could not bring himself to say ‘demon.’ “A great mystery,” he concluded.

“No, sir.” Darwin’s fat face had tightened with powerful curiosity. “We do not have a mystery. We have at least five of them. How did that man die? Who or what killed him? Where is the Heart of Ahura Mazda now? Where is its faithful guardian, Daryush Sharani, and why did he run away? And finally—least perhaps, but also perhaps strangest of all—who summoned me here to serve a dead man—when I am a servant of the living?”

Dinner at Joseph Faulkner’s house had taken a curious turn. The half-dozen guests had been drawn there at least partly by the promise of rare scientific and literary conversation from the eminent visiting physician and inventor from the Midlands. Instead they found a Darwin who was thoughtful and preoccupied. He ate his share and more of beef, parsnips, Yorkshire pudding, and horseradish sauce, but he allowed others to carry the full social burden until brandied plums and cream had appeared on the table and been disposed of. At that point he roused himself, poked with his finger for a fragment of meat lodged in his back teeth, and said, “Gentlemen—and ladies, too. If you will indulge me, I have a mind to play a game. I would like to propose a puzzle, a matter concerning which your thoughts and opinions would be most valued.”

“At last!” Joseph Faulkner waved a hand around the table. “Speak on, Erasmus. Now I will confess it, I was worried by your silence tonight. The rest of us have said quite enough. My friends all came here to hear you.”

The guests nodded, all but an aged aunt of Jacob Pole. She was very hard of hearing, but with wine at hand she seemed quite content and didn’t mind missing the conversation.

“Anyone who came to hear me will be disappointed,” Darwin said. “For I have no answers, only questions.” He glanced around the room, well lit by wall candelabra and ceiling chandeliers, and found every eye on him. “Let me narrate the events that befell me this afternoon.”

He told it carefully, summarizing everything from the arrival of the messenger at the Boar’s Head Tavern to his own departure from the Exhibition Hall for Faulkner’s house. As he spoke, he studied the others around the table.

It was a curious and curiously varied group. Joseph Faulkner kept an unusually egalitarian household, with a suitably unconventional seating arrangement for both guests and servants. Darwin was at one end of the table. At the far end was the host, and on Faulkner’s left sat Mary Rawlings, a thirty-year-old redhead with milky skin and a determined look in her blue eyes. She had her hand often and possessively on Faulkner’s arm. Darwin had shrugged mentally. His own views were liberal. Mary must know that Faulkner had a wife across the Atlantic, and she was surely old enough to make her own decisions.

In midtable there was an empty chair, intended for a manufacturer of agricultural equipment who had been detained by business in Norwich. He had sent his apologies, and into the vacant place Jamie Murchison’s heartache, brown-haired and blue-eyed Florence Trustrum, had slipped at the end of the meal. She quietly helped herself to preserved plums and coffee. Joseph Faulkner had no respect for the traditional class separations, and her switch from servant to diner excited no comment.

Darwin had made his own evaluation of Florence as she supervised the serving of dinner, and decided that she was as healthy, vigorous, and straightforward a specimen of womanhood as he was likely to find in London. Imaginary ailments were as far from her life as the surface of the moon, and that made Jamie Murchison’s remarks all the less credible.

Across from Florence sat Richard Crosse, who according to Murchison had visited her room but seen and heard nothing out of place. Seated between Colonel Pole and his deaf aunt, Crosse was a thin and intense young man in his middle twenties, slightly crookbacked and with one shoulder higher than the other. Somewhere in status between a paying lodger and a guest, he had kept his attention on his plate right through dinner. Only now did he turn dark, intelligent eyes toward Darwin.

At the end of the recital of the afternoon’s events there was a respectful silence. “So you see,” Darwin concluded, “there are five mysteries, with five questions to be answered. What thoughts do you have on any of this?”

There was another long silence. “Come now,” Faulkner said. “Theories. What about you, Richard? You are always full of wild ideas, and the only time you pulled your nose out of your studies this week, it was to tell me how excited you were about Dr. Darwin’s visit. You must have something to offer.”

Crosse shook his head, and turned beseechingly from Faulkner to Darwin. “I—I’m afraid that I—”

“No one is obliged to provide comment.” Darwin came to the rescue. “I told you, Joseph, that all I have to offer is questions. It would be no surprise if others find themselves in the same position.”

At the end of the table, Mary Rawlings was frowning and scratching the end of her snub nose with her forefinger. “Would you entertain the idea not of an answer, but perhaps of a sixth mystery?”

“Gladly. Consideration of new questions often allows us to answer old ones.”

“You never visited the exhibition, did you, and never saw the Heart of Ahura Mazda?”

Darwin shook his head.

“So you have been assuming that Daryush Sharani escaped from the locked hall in the same way as the would-be thief entered it, through an open window.”

“That is true.” Darwin was frowning. “It was my assumption, but it seems a reasonable one. On the evidence of witnesses he was certainly present at the exhibition when it closed, at three o’clock, and certainly absent when the watchman opened the doors.”

“It would be a good assumption—if Daryush Sharani resembled other men in his appearance. But he did not!” Mary Rawlings looked around the table for confirmation, and others nodded agreement. “He wore the most ornate and elaborate robes of scarlet and purple, and a tall red headdress. He also had a huge beard, big and black and bushy. There is no way that he could appear on the streets of London, even for two minutes, without being seen and remarked on by a score of people. Unless perhaps his clothes were found in the hall?”

“They were not.” Darwin was looking at Mary Rawlings in admiration. “Young lady, rem acu tetigisti. You have put your finger on an absolutely crucial point. No clothes were found, nor the great ruby, the Heart of Ahura Mazda. Nor, for that matter, the day’s takings from the Exhibition, which were supposedly in excess of five pounds.”

“So this man Sharani became disembodied,” said Jacob Pole at last. “Hm. Went up into thin air. I’ve seen a trick like that once or twice in India, but I never thought to see it in London.”

“Nor will you.” Darwin roused himself and snapped his fingers. “Rather the opposite. Ah, what a fool I am! I did not have the sense to observe the results of my own actions.” He turned to his host. “Joseph, do you have a carriage available?”

“Of course. But why? You cannot be leaving already, when it’s not yet nine o’clock.”

“I must.” Darwin stood up. “I must go back to the Exhibition, to demonstrate to myself that I am indeed an imbecile—and would have remained one, but for the valuable assistance of this company. And anyone who cares to come with me will observe the evidence of my folly.”

The afternoon’s foggy damp had been succeeded by a hushed and relentless rain, enough to keep anyone indoors with no urgent reason to be abroad. The interior of the coach was drafty and wet, but Darwin was in high spirits.

“The true disgrace is that I noticed it!” he said, as they clattered through empty streets toward the Thames. “And yet I did not apprehend its significance. When I was in the hall, I banged my stick on the stone floor, and remarked even then that the sound was strange. There was a boom to it, like an echo. I thought to myself, ‘Rafters,’ but the timbre was wrong. The echo was—under the floor!”

Five of them were riding the coach. Joseph Faulkner had not asked who else might be going with Darwin—he was, and that was the main thing. Mary Rawlings had shown as much determination, grabbing Faulkner’s arm so that he could not move without towing her along. The fourth in the coach was Jacob Pole. Scenting an adventure, with perhaps a priceless ruby at the end of it, he had arranged for his aunt to be taken home without him. She seemed puzzled, but made no objection. Last came Richard Crosse. He had swung aboard uninvited, sitting up next to the coachman in the pouring rain and as jittery as ever. He leaned over to look inside the coach, seemed on the point of a flood of speech, then as suddenly sat upright again.

The rapid night ride took less than five minutes, and at the hall Darwin bustled on ahead of the others. He stood before the great double doors, lantern in hand, and cursed mildly.

“Ahriman’s ghost! Padlocked again—when now there is nothing to steal.” He turned to Richard Crosse. “You are more limber than I. The back window, then, and unbolt the side door.”

Crosse melted away into the darkness without a word. Thirty seconds later there was a rattle of bolts, and Darwin could stride inside. He walked five paces, wiped his forehead with his sleeve, and held the lantern high. “Do you see it? What we seek, of course, is some way down through a solid stone floor.”

It was Mary Rawlings who found it, over in one dark corner of the hall. The hinged wooden trapdoor had been painted grey and sanded over, so that it resembled stone flags. When it was lifted she hung back, nervous for the first time, but Darwin unhesitatingly swung the panel full open and peered down. He listened intently. A moment later he had laid the lantern on the floor and was descending into blackness.

“Pass the light down to me.” His voice came back hollow and distant, added to a nearby sound of trickling water. “Then come yourselves.”

Joseph Faulkner went first, with a caution appropriate to his age. The others followed, with Jacob Pole firmly in tailguard position.

“Guarding the rear,” he muttered.

“Aye, Jacob.” Darwin’s voice boomed from the darkness ahead. “Your own, no doubt.”

They were emerging to stand on a long wet ledge about five yards wide. Beyond it, black and restless, flowed a stream of twice the width.

“It’s a river,” Mary said. “A real underground river.”

“It is.” Darwin was staring around him with vast satisfaction. “And it should be no surprise to us. London is ancient. We tend to forget the obvious, but this city, too, was once no more than woods and meadows. Most of the old streams run now below the surface, invisible and out of mind. And this must be one of them.”

“You know, ’Rasmus, you’re quite right.” Jacob Pole was leaning over and staring at the water, his mouth open. “And me a Londoner, native born. I ought to be ashamed of myself. I knew this from my childhood. There were four old rivers on the north shore, the Walbrook, the Fleet, the Tyburn, and the Westbourne. Unless my old schooling serves me false, this must be a spur of the old Walbrook. The main river rises in Finsbury, and runs close by the Mansion House. It joins the Thames by Dowgate—or used to; but I’ve heard no mention of it for years and years.”

“But what are you seeking here?” Mary stepped close to the lip of the stream, peering over the worn stone edge at the water. “Is it that?”

She was pointing down. In the moving water, firmly supported by metal braces from the stony edge, sat a new structure. It was a waterwheel, and it was turning steadily under the pressure of the flow.

“That will do excellently well for a beginning.” Darwin hunched low, and examined the wheel’s construction. “Skillfully made,” he said after a moment. “And recently set in place. There is a natural steady flow from the river, but I think temporal variation comes mostly from tidal change. Now then. Here, things become more interesting.” He was moving with the lantern, following a pair of long black lines that ran from the wheel’s center, into a complex tangle of broken gears and wheels, then finally appeared again to run across and up the slippery wall. He bent low, and scraped at the surface of one of the lines with his thumb nail. There was a glint of metal beneath.

“Where do they lead?” Faulkner asked. Mary Rawlings was holding his arm, in real or simulated nervousness, and the older man was enjoying the whole experience. “What’s above there? It must be part of the hall itself.”

“It is.” Darwin followed the lines up with the lantern’s beam, until they disappeared into the ceiling. “We are exactly beneath the pedestal. If it were present, the Heart of Ahura Mazda would stand right above us.”

“But where’s the Guardian?” Mary asked. “Weren’t you expecting to see Sharani here?”

“I was hoping to do so. I was not expecting it.” Darwin ventured along the stony side of the underground stream, leading the way quietly through dark and filthy culverts. Water dripped steadily onto their heads from dark wooden beams and brick arches, the latter furred over with mildew and patches of grey fungus. All the while, the rain-fed stream murmured along no more than a yard from their feet.

“Aha.” Darwin paused, half a dozen paces ahead of the rest. “Something new. Bring the other light, Joseph, and let’s take a close look.”

He had reached a forlorn heap of garments, bright scarlets and purples dulled by lantern light. Beyond them, the stream branched into three smaller tributaries.

Darwin lifted a glittering robe and turban. “The servant of Ahura Mazda. Vanished into thin air, as Colonel Pole suggested, at this very point.” As he spoke, a cold air blew through the tunnel, rippling the cloth in his hand.

Pole gave a little grunt and retreated a step. “Disembodied. Then we can follow him no farther with human agents?” His voice hovered between hope and disappointment.

“We cannot,” said Darwin cheerfully. “However, that does not mean he cannot be followed by inhuman ones. Friend Daryush Sharani has made a most serious mistake. He should have thrown his outer garments into the river, rather than leaving them here. Don’t touch the rest of these clothes.” He turned to Faulkner. “Joseph, we require assistance. Can you find me a pair of bloodhounds?”

“At this hour? Erasmus, you certainly ask a lot of me.” But Faulkner sounded delighted, and after a moment he turned to Crosse. “Richard, you know Tom Triddler’s place, up past the Mansion House. Would you go there, and ask him for a pair of his best tracking hounds? Tell him it is for me. You’ll have to bang on his door, because he’s half deaf. But keep hammering. He’ll come.”

Crosse hesitated, turning his head to one side and opening and closing his mouth. Finally he nodded and hurried away into the darkness without speaking.

“I just don’t know what’s got into Richard tonight,” Faulkner said. “He’s behaving very odd. So witless and confused, you’d think he was in love.”

“He is certainly that,” said Darwin. “With Miss Florence Trustrum. Is it not obvious to you? He regards her with the hopeless yearning of a mortal for a goddess. Knowing your own fascination for such things, I am only astonished that you did not observe it long since.”

He walked slowly back along the tunnel to the place where they had entered, and squatted down on the wet stone. And there, as unconcerned as though he sat in Faulkner’s warm parlor, he began to examine in detail the mass of gears, wheels, wires, and pulleys that sat directly beneath the pedestal in the Exhibition Hall.

“Broken,” he said after a few minutes. He held up a handful of components. “Quite deliberately, and beyond repair. I conjecture that several elements have also been removed. Without hints from its maker, its purpose is hard to divine.”

“Never mind that old junk.” Jacob Pole had been wandering moodily around, staring down now and again at the dark water. “I was hoping for excitement and treasure, not standing around in a smelly damp sewer. Are you really expecting a dog to be able to track down here, in the cold and dark? Tracking dogs need light and air.”

“Not at all, Jacob. That is an old wives’ tale.” Darwin raised himself laboriously to his feet. “A good tracking dog will follow a scent as well at night as during the day, as well for a nonliving scent as for a living spoor, and as well underground as on the surface. If we are looking for a mystery tonight, we will find none greater than a hound’s nose. It possesses subtleties for distinction of odors that we can scarcely imagine. How many centuries will it be, think you, before mankind will produce a machine to rival the nose of a dog for sensitivity and discernment?”

“Well.” Pole sniffed. “I’m not persuaded. We’ll see, soon enough. But I’d always been told that if you took a tracking hound into a dark, airless place—”

He was interrupted by a cry from above, and a sound of clattering footsteps overhead.

“Here they come,” Darwin said. “And now perhaps we can observe one of the wonders of Nature.”

Richard Crosse came down the ladder first, carrying a mournful-looking black hound with jowls and ears that hung below its lower jaw. After him came a rumpled man carrying a second dog.

“Late work, Tom Triddler,” said Faulkner cheerfully. He rubbed his hands. “No matter, I’ll see you’re well rewarded for it. Good trackers, are they?”

“Best I have, sir.” Triddler put the dog down and swept off his cap, to reveal a totally bald head. He put the cap on again hurriedly. “Cold down here.”

“But that will not interfere with the hounds?” Darwin asked.

“No sir. Nothing does. Not cold, not dark, not nothing.”

Darwin nodded to Pole. “There, Jacob. You will see that your fears are groundless.” He turned to Tom Triddler. “Are we ready to begin?”

“I am, and the dogs are.” Triddler stared around him. “What an ’ole. Wouldn’t like to come courting down ’ere. Got a scent for the dogs, ’ave yer? Old sock, somethin’ like that.”

“This way.” Darwin led them to the heap of discarded clothing. “Any one of these should do it.”

“Aye. Perfec’.” Triddler drew the two hounds to the pile and pointed down. The dogs snuffled and wagged their tails furiously, while all the people clustered round them. “They’ve got it now—an’ off we go. Go on, now, Blister. An’ you, Billy, on yer way.”

He was holding the two leashes lightly, while the dogs sniffed and snuffled. “Go on, now,” he repeated. “We’re waitin’. We don’t ’ave all night.”

His second urging was very necessary. The two dogs had turned around once, then settled on their bellies on the floor, tails wagging happily. But when Tom Triddler shouted them again into action they sank to rest, their jaws on the cold stone. Their tails drooped, and they stared at him with mournful eyes.

After another few attempts to spur them on, he shook his head. “I’ve never seen nothin’ like it, Mr. Faulkner. They won’t budge. Not an inch. Seems they don’t like it ’ere underground.”

“What did I tell you?” Pole gave Darwin a superior nod, and began to retreat toward the ladder. “I think the dogs have the right idea. It’s damn cold down here, and it stinks. As you said, ’Rasmus, dogs have powers that we lack. They know we’ll find nothing more. I’m ready to go home.”

“Powers that we have lost,” Darwin muttered, but his tone lacked its usual conviction. In his disconsolate manner, he was a good match for the two bloodhounds. “I was quite convinced… But maybe you are right, Jacob. We will accomplish nothing more tonight. We might as well to bed.”

He limped after Pole toward the ladder, so rumpled and so woebegone that Joseph Faulkner called after him: “Come now, Erasmus. There’s always tomorrow.”

“Aye,” came the testy reply over Darwin’s shoulder. “Another day to make a fool of myself.”

“Ah,” Faulkner said softly to Mary Rawlings. “That’s not our Dr. Darwin, founder of the Lunar Society and Europe’s leading physician. That’s gout speaking. Come along, my dear, let’s be out of here. There are more pleasant nighttime pursuits than underground sewer wandering. And in the morning you will see a new Erasmus.”

But the morning came to a city immobilized. During the night, the rain had frozen and then turned to snow. A deadly sheath lay on every flat surface, from east of the Tower to a mile past Westminster. A few hardy (or foolhardy) merchants had ventured forth, their draft horses skidding and shivering on treacherous roads, and after a hundred yards retreated. By ten-thirty the whole city was again shrouded and quiet.

Darwin sat in the parlor at Faulkner’s house. He and Jacob Pole had been persuaded to stay over, but now he was chafing with impatience. The revelation had come to him during breakfast. There was a way to trace Daryush Sharani, and a sure one—if only Darwin could pursue it. But his weight and his gout together conspired against him.

Finally he went to Florence Trustrum’s room on the ground floor, and asked her if she would deliver a letter to Jamie Murchison. She muffled herself in a wool head shawl, thick overcoat, and ugly leather boots, and set out into the still, white wilderness. Darwin sat at the window, counted the seagulls perched on the gable roof, and wondered at the instinct that sent them flying far inland when the northeasters blew in with the winter storms.

Florence returned breathless in little more than half an hour. “Jamie will do it this morning,” she said.

“You are upset.” Darwin took her by the hand. “What happened?”

“It was… nothing.” She gave him a direct glance from bright blue eyes. “Oh, why not. I will tell you. Jamie—he asked me to marry him.”

“Ah. And you replied?”

“I told him—that I did not know. But I think I do.” She was gone, leaving the smell of warm wet wool behind her. Darwin nodded to himself, and went back to watching seagulls.

It was after noon when Murchison arrived. Joseph Faulkner, Jacob Pole, Florence Trustrum and Darwin were again in the dining room, enjoying a quiet lunch of cold pork, applesauce, sage and onion stuffing, and hot boiled carrots. Darwin had left instructions to the staff and Murchison was shown in at once, snowy boots and all. He hesitated on the threshold.

“You have it?” said Darwin eagerly, through a mouthful of pork crackling.

“I do. I went to the chandlers as soon as I received your message.”

“And you found an address?”

“I did.”

“And it is?”

Murchison looked at Joseph Faulkner, gulped, and stammered: “They gave me an address for the delivery of just the goods that you listed. But it was here!—this very house!”

“What!” Darwin stared at Faulkner, who shook his head.

“No good looking at me, Erasmus. I have not the faintest idea what you two are talking about.”

“This house.” Darwin subsided into his chair. After a few seconds of open-mouthed gaping at his empty plate, he closed his eyes and breathed a vast sigh. “It is so. And at last I see a whole picture.” He stood up. “Come on. All of you.”

With the other four trailing along behind, Darwin headed for the ground floor and the rear of the house. At a closed door he knocked and went straight in.

“But this is Richard’s room!” protested Florence.

“Aye. Mr. Crosse is fortunately in absentia at the moment. So let us see—what we shall see.” Darwin had moved to the writing desk by the window and was coolly opening drawers and examining their contents.

“Erasmus, this is a little too much.” Faulkner moved to Darwin’s side. “Richard is from an old Somerset family that I well respect, and I think of him as my guest. To see his room commandeered in such a way, and his private belongings despoiled—”

He paused. Darwin had reached deep into a left-hand drawer of the escritoire and pulled out a large, glittering stone.

“The Heart of Ahura Mazda.” He brought it close to his face, turning it to allow its facets to catch the light from the window. “Hm. Jacob, what do you think? This is more your department than mine.”

Pole took the gem and examined it for no more than two seconds. He sniffed and handed it back. “What a letdown, after such a chase. That’s no ruby, priceless or otherwise. It’s nothing more than high-quality glass. Cunningly cut, I’ll admit that. I’d give you a shilling for it.”

Darwin plunged his hand again into the drawer. “And now we have a part of the Guardian himself. His beard.” In his hand was a tangle of hair, thick and black and bushy. “And as for the rest of Daryush Sharani…”

Darwin looked past Faulkner and the others. “Come in, sir, and claim your possessions. My behavior here leaves much to be excused.”

In the doorway, face ashen, stood Richard Crosse. The dusting of snow on the shoulders of his black coat matched his countenance. At Darwin’s gesture he moved forward and sank down to sit on a narrow window seat.

Darwin stared at him for a moment, and his expression changed. “When did you last have food and drink?”

Crosse shook his head. “Last night? This morning? Sir, I am not sure.”

“This must not be.” Darwin went to Crosse and gestured to Jacob Pole to support him on the other side. “We will go to the dining room, sir, and you will eat and drink. I will advance hypotheses, and you will correct me as you choose. Silence, now—I neither need nor expect an answer yet. Speak if you must, but above all, you must eat. Remember the natural law of the world, Mr. Crosse. Eat, or be eaten!”

It was an odd little procession. Joseph Faulkner and Florence Trustrum led the way, he looking back over his shoulder all the time. Next came Darwin and Pole, supporting Crosse between them. He walked like a zombie, without either volition or resistance. Last came Jamie Murchison, stolid young face scowling in puzzlement. At the door to the dining room, Crosse at last lifted his head and stared straight at Darwin.

“How did you know? How could you possibly know?”

“I know only part. I conjecture much. And on one central element, I am so ignorant that I scarce know what to ask you.” Darwin steered Crosse to the table and nodded at Florence to fill a plate with roast pork and carrots and a glass with a mixture of beer and brandy. “But I do know where to begin. It is to assure you, Richard Crosse, that I know of no law that you have broken. You are as innocent as I, or the colonel who sits at your side.”

Pole’s audible sniff suggested that might be no great reassurance, but Darwin went on, “In a legal sense, you are blameless. But in a moral sense, Mr. Crosse, things are more complex. You sought to obtain assistance for a dying man, when many would have thought only of flight. That was commendable. But you were guilty of one universal failing—something that we all do, all too often. We wish to prove our own cleverness and importance to the whole world.”

Crosse bowed his head in assent. After another unhappy look at Darwin he picked up a fork and at last began to eat.

“I am as guilty of that as anyone,” went on Darwin. “Do you know where my own thoughts began on this matter? In as self-centered and introspective a place as one could dream of. I asked myself, who knew that I, Erasmus Darwin, was at the Boar’s Head Tavern yesterday afternoon? For only someone with that knowledge could seek to summon me to the Exhibition.”

Florence Trustrum, showing excellent instinct, placed another piled plate of food in front of Darwin. He began to eat with his fingers, his eyes never leaving Richard Crosse.

“Let us define that small group of people. Joseph Faulkner and Jacob Pole certainly knew, since they were there with me. Mary Rawlings also presumably knew. Jamie Murchison knew, but since like Colonel Pole he was there with me when the message came, that struck him from the list of candidates. Who else? It seemed that there might be several others, but they must all be people close to Jacob Pole or Joseph Faulkner. Only they could know that we were meeting at the Boar’s Head during the afternoon. So. The possible universe was circumscribed. But I could go no further with logic alone, to point a finger at one man or woman. Something new was needed. That something was what I hoped to find when we returned to the Exhibition Hall last night. At first, I thought that I had discovered it. The garments of Daryush Sharani were my guide, and they would allow us to follow him. But the hounds proved useless. I returned to this house, as baffled as I have ever been in my life.” Darwin shook a finger at Pole. “You, Jacob, had already been planting doubts in my mind, suggesting that the hounds would prove useless at night and underground.”

Pole shrugged. “I was right. They were useless, ’Rasmus. They told us nothing.”

“Only because we asked them the wrong question. A dog can answer only in a dog’s terms. Remember when Tom Triddler released the hounds? They sniffed at the clothing, and wagged their tails, and were all excitement. It was only when he shouted at them again, and told them to hunt for the scent, that they lost all enthusiasm. As well they might! They had done their job, and they knew it. They did not deserve harsh words from their master. The source of the scent of the garments was right there—in person.” Darwin pointed to Richard Crosse. “The hounds knew it, and they told us all that they could tell. Was it their fault that we were unable to read the message?”

“But why?” Jacob Pole scowled at Darwin across the table. “I don’t know about all this dog’s mind reading, but what is the point of all this? False rubies, and curses, and fancy dress, and deception. But ’Rasmus, say what you will, a man died at the Exhibition. You seem to be forgetting that.”

“Not at all. We come to it now.” Darwin licked his fingers, and nodded across the table at Richard Crosse. “Sir, I could make my estimate of the whole course of events. But at this point, I think you ought to make your statement. Remember, I am not the magistrate, nor is Mr. Faulkner. But a magistrate will be here, if we find it necessary to call for him. Forget your reticence, and speak. Let me preface you with only this: after I examined the contrivance in the river vault beneath the Exhibition, I suspected that the unusual materials for its construction would have been purchased from a local chandler. We have confirmation of that; your own name is I suspect to be found on the receipts.”

Richard Crosse laid down knife and fork and stared in turn at each person seated around the table. He bit his lip. “I will tell. But after yesterday’s disastrous events, I pledged my own soul to make no public revelation of one element of this affair. For all the rest, Dr. Darwin has said it for me. I wanted to prove my own cleverness, by a successful hoax on the whole world. You see, I had the means to do it—a method of my own devising, that would hold a grown man helpless. And it would do no damage.”

“To a well man,” said Darwin. “But for a man already suffering from degenerative heart disease, like the would-be thief…”

“I know that now—too late.” Crosse rubbed at his gaunt jaw. “I thought that I had a harmless hoax. I would fool all this great city with the Heart of Ahura Mazda, and with the great exhibition of the power of the jewel. And then Daryush Sharani would disappear forever. I never intended to boast of my success, or to tell of the hoax. But I was the fool.”

“And you were taking people’s money,” Florence Trustrum said.

He nodded at her. “I was. But never with thought of personal gain. The takings were a small amount, far less than the cost to me, and people seemed well pleased with what they saw. My family is well-to-do. If the weather had not turned so foul today, I would be on my way home to Fyne Court, in Somerset. I intended to say no more to you and Mr. Faulkner than that I was tired of life in London, and preferred the quiet of the Quantock Hills.”

“Which would be a pity,” Florence said softly.

“But the Earl of Marbury!” Joseph Faulkner, at the end of the table, broke into the conversation for the first time. “And all the other men made helpless by your ‘demon.’ What of them? I can accept the facts of your imposture, and even your disguise as Daryush Sharani. There is nothing new in elaborate robes and false beards. But you have said nothing to explain the true mysteries: how the Earl was persuaded to cooperate with you, or how the man died yesterday when he attempted to touch the Heart of Ahura Mazda. That is what we need to hear.”

Richard Crosse stared down at the tablecloth and shook his head. “I have promised myself that I will never speak of that. If I were able to forget it myself, I would do so.”

“Then we’ll have the magistrate in, and the devil with it!” Faulkner slammed his hand down on the table. “Without the rest, what you have said is no explanation at all.”

Crosse did not look up. “So be it,” he said at last. “So be it.”

Darwin held up a hand greasy with pork fat. “One moment, Joseph, before we rush to the law and the clumsy clutch of official justice. Mr. Crosse, I do not ask you to go beyond your own conscience. But I do ask you to come with me and listen to what I have to say. Colonel Pole and Mr. Faulkner will accompany us, under condition that they promise to remain silent on what they hear.”

“You are my guest, Erasmus, and you would swear me to silence in my own house!” But Faulkner was already on his feet. He led the way out, turning as he left to say, “Florence, this is the day for hot chocolate. Order for yourselves, would you, and have a pot brought through to us.” He glanced at Darwin. “A big one.”

The panelled study across the entrance hall was unheated, and cold enough for frost patterns to sit on the inside of the window panes. Faulkner shivered, gestured to the armchairs, and sat down hard himself on a stuffed ottoman. “Should I have the fire lit in here, Erasmus?”

“I think not. This will be brief.”

Faulkner rubbed his hands together. “Speak, then, before we all freeze.”

“Without delay.” Darwin turned to Richard Crosse. “I begin with a statement that might be considered more as personal opinion than fact. To men of inquiring minds, few elements of today’s natural philosophy excite so much interest as the experiments of van Musschenbroek of Leyden, von Kleist of Pomerania, Benjamin Franklin of Philadelphia, and of our own Jesse Ramsden. Would you not agree?”

“You know all!” Crosse’s face went even paler, and his dark eyes widened.

“Far from it. I know a little, and I guess a great deal. But let me imagine a tale for you. Suppose that we have a young man, one of feverish imagination and genuine inventive powers, who reads of the findings that I mentioned, and becomes fascinated with the whole field of electricity. He reads Mr. Franklin’s great work, Experiments and Observations, and Mr. Joseph Priestley’s encyclopedic History of Electricity. And his own imagination is, to employ an appropriate term, sparked. He has original ideas. He himself begins to experiment—but secretly, because he is still unsure of where his own notions will lead him.”

“Dr. Darwin, you are a wizard! How can you know these things?”

“He’s right, ’Rasmus,” Pole added. “How the devil do you know?”

“I do not know. But events in this house gave sufficient reason for conjecture. Observe.” Darwin leaned across to the desk and picked up an amber paperweight. He rubbed it hard against his own rough jacket, then held it out toward one of Joseph Faulkner’s fur caps, perched on the arm of a chair. “See how the fur moves, to set each of its hairs separate from its neighbors. It is the oldest electric effect, already well known to the old Greeks—our very word, electricity, derives from their word for amber. When I heard that Florence Trustrum had reported her own hair standing separate on arms and legs, and odd sensations on her skin, within this very house, my thoughts turned idly to Leyden jars, and to electric sparkings. But I dismissed the idea as an irrelevance, and my musings went no further. Then last night I saw the underground vault, and within it the diverse but mysterious apparati of some electrical experimenter, copper wires and bars of iron and plates of lead. Yet still I made no connection! Only today, with the chandler’s report of materials delivered to this very place, did my brain offer its synthesis. I recalled the smell of Exhibition Hall when I arrived there—the very air itself held the whiff of electrical discharge. And, at last, I could offer a rational explanation of the hounds’ failure—or rather, to be fair to them, of their success. But who would have suspected it, that Daryush Sharani was last night one of our own company.”

“You would.” Richard Crosse had somewhat recovered his composure. With his secret revealed, a more thoughtful, fatalistic man emerged. “Your every suggestion is precisely right. So now I ask, knowing all, what do you want of me?”

“Knowing all?” Darwin started up in his chair. “Why, man, I know nothing of the most fascinating part of this whole business: what is your machine, that could render a would-be thief totally helpless, and how does it work? That’s what I want to know, not the details of glass rubies, stage magic, or deception.”

Crosse averted his eyes. “That I have sworn to myself I will never reveal. It has done enough damage already. If it were ever to be broadcast…”

“It would not be.” Darwin was wriggling in his seat with excitement. “Not by me, or Jacob, or Joseph. I swear that what you tell us will go no further. On that you have my word as a physician and a human.”

“What of the others?”

“Well, I suppose.” Faulkner glared at Darwin. “Damn it, Erasmus, don’t you think that Jacob and I ought to be allowed to make up our own minds? I know that to find out what’s going on here, you’d be quite happy to pawn our souls.” He turned to Pole. “What do you say, Jacob? I will go along with this, if you will.”

“Right.” Pole nodded to Richard Crosse. “Be assured of our silence, and speak on. Anything you say to us will never be breathed to another mortal. Though so far as I’m concerned, I’m as sure as a pig’s tail curls that I’ll not understand more than two words of your explanation.”

“I wish that were true. But it is elementary, at the same time as it is mysterious.” Crosse went to the desk and took out paper, pen, and inkwell. “I have results, but no sound basis for a scientific explanation. A turning wheel, like the waterwheel that you looked at last night, bearing magnets both fixed and moving, will produce a flow of electricity in loops of wire—the long copper lines, that you saw beneath the Exhibition Hall. And that flow, passed through other coils that I took out of the machine and threw into the river, becomes a force strong enough to bind a man immobile. I attached one wire to the metal plate around the pedestal holding the Heart of Ahura Mazda, and one to the metal rim of the protecting glass case, in such a way that I could disconnect it from the side of the pedestal itself without others seeing my action. It was connected thus.” He sketched a series of simple diagrams in black ink, labeling each one as he did so. His trembling hands grew steady as he worked. “I assure you, I had tested this machine a hundred times on myself. It freezes the subject, with an indescribable feeling both pleasant and unpleasant at once. Free movement is impossible, but when the flow ceases there are no harmful aftereffects, merely a continued tingling like pins and needles.”

“And that is what you did to the Earl of Marbury?” Darwin was peering at the sheet, his eyes alight.

“Exactly that—with no ill result afterwards, to him or to anyone else who tried the same. It seemed a perfect device for protecting the Heart of Ahura Mazda, the word of which would quickly spread all around London and assure the total success of the hoax. As soon as that game was over, I intended to explore the electrical effects that I had discovered until I had plumbed their deepest meaning. But after the death of the thief yesterday…” The face of Richard Crosse had filled with life and energy when he talked of his work. Now it clouded.

“I cannot explain why it proved fatal,” Darwin said softly. “But I can suggest several avenues of thought that should be followed. First, the thief was wearing shoes that were broken and wet. As you and I both know, damp increases electric flow. More important, I suspect, was the swollen and thaw-fed condition of the underground river. If the rate at which the waterwheel turns dictates the level of the charge received by the pedestal, our wretched thief could have received an impulse many times that of your earlier experiments. Enough to blister his hand, and enough to provide a fatal jolt to an already weakened heart.”

“Your suggestions are ingenious. But they will not be the basis for future experiment. Never again will I pursue such reckless follies.” Crosse fell silent and hung his head as Florence Trustrum came into the room carrying cups, saucers, and a large silver pot of hot chocolate. He looked up only to give her a quick smile of thanks as she placed the tray at his side.

“What are you going to do with me?” he asked, after she had left the room. “You are right. I did not check sufficiently the natural variations in the electric force. A man is dead who should be alive.”

Darwin raised his eyebrows and glanced at Pole. “Jacob?”

“Me?” Pole favored Darwin and Crosse equally with his scowl. “Why, damn it, I’m not going to do anything at all. If a thief and a rogue is dead who should have been arrested, I say, good riddance. It’s time saved for the hangman.”

“Very well. Joseph?”

“I agree with Jacob. And it’s no concern of mine if the honorable citizens of London Town flock to see a hoax. From what Florence said, she and the rest more than got their money’s worth. I don’t want any more thaumaturgical exploits in this house—even if you call it science, Richard. But for the rest, my opinion of you has not changed. You are still welcome to stay here with me.”

“Thank you, sir, but I must go back to Somerset.” Crosse gave the closed door a long and unhappy look. “I should go at once.”

“Go if you must, if that is your decision,” Darwin said. “But if you others will permit it I would like one private word with Mr. Crosse. Alone. And it is nothing, I assure you, to do with electricity.”

“And thank the Lord for that.” Jacob Pole stood up and moved toward the door. “I said I wouldn’t understand all your technical talk, and I was right. Electricity. What a waste of time and effort.”

“Agreed.” Faulkner was following Pole through the doorway. “Does anybody understand this thing called electricity?”

Darwin and Crosse looked at each other. In unison, they shook their heads.

“We do not, Joseph.” Darwin smiled. “Not yet. For it is as your great countryman, Mr. Franklin, puts it so well in one of his letters: ‘If there is no other purpose for the electricity than this, it may serve to make a vain man humble.’ ”

Jacob Pole paused, the door knob in his hand. “Then you should get Mr. Crosse’s machine, ’Rasmus, and take a double charge for yourself.”

He closed the door before a response could be offered. Darwin shook his head and tried not to grin. “Pardon me, Mr. Crosse. I have known Colonel Pole for a long time. If I may again become more serious, my previous inquiries of you were motivated by scientific curiosity. What I say now has no such origin. You may choose to regard it as an unwarranted and unconscionable intrusion in your private affairs.”

Crosse had been quietly tearing to pieces the diagrams he had drawn of his equipment. “Continue,” he said. “I have at least been provided with fair warning.”

“Very well. The subject is Florence Trustrum. You look on her with favor?”

“Is it so obvious?” Richard Crosse’s voice was bitter. “I try to hide it. I look on her with favor, and more than favor. But as you see, I am not made to—to ‘court an amorous looking glass.’ ” His hand went to his left shoulder.

Darwin snorted. “And yet your namesake, Richard, that you now choose to quote, ascended to the throne of England and wed the woman of his choice. Stop your self-pity. You are as whole as any man in this house, if you but think yourself so.”

“I cannot entertain that thought. I will be returning to Somerset as soon as the weather permits—if I am free to do so.”

“You are free. But I urge you not to go. You should stay here, and determine if Florence feels an equal warmth for you.”

“She has no need of me. A new suitor is already here. You saw him.”

“I did. I suggest that he is no threat to you in Florence’s eyes. Mr. Murchison is a pleasant young man, and probably an honest and an honorable one. I wish him no hurt, and I should not be taking sides. But let me say this: the world is full of pleasant, handsome men, as harmless and as simple-minded as Jamie Murchison. You are different. You have that rarest gift, the one that marks our transition to a higher being. You have creativity; an inspired inventiveness coupled with true scientific instinct.”

“A creativity that kills. Dr. Darwin, I am flattered, I cannot deny it. But there are others far more ingenious than I.”

“No, sir.” Darwin spoke with great authority. “Trust me in this. There are all too few such, in any time and place. London today does not contain five such men and women. If you do not pursue the great problems that you alone can see, who will pursue them? Mr. Faulkner, or Miss Rawlings, or Colonel Pole? Never. We may have the desire, but we lack the divine touch. Perhaps you think that your own children will do what you will not? Maybe. But only if they exist. You, and people like you, have a duty to the world: you must marry, and love, and propagate.”

Richard Crosse removed his hand from his left shoulder and stared quizzically at Darwin. “Yet you are single, sir.”

The older man paused. It was many seconds before he answered. “Aye. For now, but not I think forever. And I have children already, from a former marriage. However, you make an excellent point. I should be truer to my own principles. I will remember that.”

Darwin stood up, patted Crosse’s shoulder, and walked across to the door. On the threshold, he turned. “I am going to join the others now. Florence Trustrum will be back here in a few minutes, to collect the cups and the chocolate. She is fond of you. Say to her what you will. But say it.”

“Sir, one moment.” Crosse hurried to Darwin at the door, his pale face suddenly resolute. “I will try, surely I will try. But you should know that I have no gift for honeyed words. I have tried ten times to tell Florence how I feel, and each time I have failed.”

“Then, Richard, you must try an eleventh time.” Darwin smiled his gap-toothed smile. “Courage, man. Nature leaves no space in the world for failures. You can win. See here.” Darwin reached into his pocket, and pulled out a glittering chunk of red glass. “Here is your own creation, the Heart of Ahura Mazda. Look on it when you speak to her. Surely the man who could conceive this can win a heart to replace it.”

Crosse nodded, and took the jewel. Darwin finally closed the door, turned, and headed toward the rear of the house. He walked without noticing where he was going, absorbed by a new and intriguing thought. If Richard Crosse did not try again and did not win, why then, that very failure made him unfit to sire descendants. And the same idea could be applied to every field of activity, for animals as much as for men. A grand principle was at work, Nature forming what it needed for future generations, by an inevitable and continuous weeding of the present. It was happening now, and it had happened always.

Erasmus Darwin walked on, right past the room where the others were waiting for him. The smell of fresh-baked bread drew him by instinct toward the kitchen, while his mind strayed far away. Already he was wondering how his new thoughts could be framed in their most general form.