Galileo, Detective by Theodore Mathieson

How Galileo experimented with two falling bodies, dropped from the Leaning Tower of Pisa — with spectacular results!

On an evening in the spring of 1590, the young professor Galileo Galilei hurried along the Via S. Maria towards the river Arno, now and then glancing back at the empty moonlit streets. He paused for breath in the centre of the Ponte di Mezzo and listened to the water swirling in full flood beneath the bridge.

The city of Pisa lay peacefully quiet around him, her skyline of belfries, cupolas, and thrust-up loggias black against the luminous night sky. Now the bells of the Duomo began to ring with reassuring sweetness through the still, warm air.

When he had rested a few minutes, Galileo continued across the bridge and into the southern section of the town, turning presently into a side street, where the way, although narrow, was lined with substantial homes. He stopped before a square, brown house, faced with white stone — the home of Jofre Tarrega, professor of philosophy at the university.

Galileo’s knock brought to the door a buxom housekeeper who greeted him pleasantly in a broad Calabrian accent, and then showed him into the living room.

“The signorina is not at home, maestro,” she said smiling. “She is visiting her aunt in Lucca, but we expect her to return to-morrow.”

“I know, Guilia,” Galileo said. “I came to see Signor Tarrega this time.”

“I will tell him.”

Jofre Tarrega appeared almost at once, clad in his riding clothes. He took off his leather gloves and threw them upon a table.

“Ah, Leo,” he said opening his arms in greeting to the stocky red-haired young man. “I’ve just had a fine moonlight ride on the Cascina road. Guilia sounded concerned about you, and indeed, you do not look happy. Is there something I can do for you?”

Galileo looked soberly at the proud, thin-lipped man, who had the lean but powerful body of an expert swordsman.

“I need your counsel, Signor Tarrega,” Galileo said. “As my colleague at the university, and the only one who has opened his home to me, perhaps you could tell me what I should do about this.”

From his pocket Galileo drew a folded note and handed it to Tarrega. The latter stooped before a lamp and read the message slowly aloud.

“ ‘Your denunciation of the truths established by Aristotle is prompted by the Devil. Beware! He soon will come to claim his own.’ Well, now, Leo, where did you get this?”

“I found it upon the lectern after my class left the hall this afternoon.”

“And upon what have you lectured of late?”

“I have been investigating Aristotle’s statement that bodies of different weights move in one and the same medium with different speeds. To-day, for example, I demonstrated how wooden balls of unequal weight, when rolled down an incline, reach the bottom at the same time.”

“Then you have successfully refuted Aristotle!” Tarrega exclaimed.

“Of course. I can prove it to anyone who will take the trouble to look.”

Tarrega clicked his tongue. “You know, of course, that the faculty stands united against these demonstrations of yours. Isn’t it likely this was written by one of them?”

“Yes. I am the youngest professor, and they resent my questioning their sacred Aristotle. But I suspect an outsider.”

“Who, then?”

“Giovanni de Medici.”

“Giovanni, the grand duke’s brother?”

Tarrega appeared startled. A widower of Spanish origin from Catalonia, the professor was distantly related, through marriage, to the Medici family, and although Tarrega’s fortunes had not waxed greatly through that connection, he was nonetheless passionately proud of the distinction.

“You see,” Galileo continued, “shortly after I came to Pisa, Giovanni de Medici asked me if I would examine a model of a dredging machine which he had designed. I did, and told him it would never work.”

“Tact is a quality you should cultivate, Leo.”

“Perhaps. But it was the truth. Anyway, Giovanni was so stubborn he had a big dredger built and tried to dig out the harbor at Leghorn. All the machine did was sink so far into the mud that they couldn’t get it out. Since then, when Giovanni passes me by, he makes a sign against the Devil.”

“You apparently have a way of making dangerous enemies, Leo,” Tarrega said. “And I cannot see how I can advise you.”

“But what would you do? Confront Giovanni with the note and demand an explanation?”

“Look here, Leo, you must learn to control your impulse to fling down challenges — that is the reason you have more than one enemy on the faculty. My advice to you is to restrain yourself. Especially do not challenge Giovanni de Medici, or you will find yourself in serious trouble with the rector of the university.”

Galileo shrugged uneasily. “I know, Signor Tarrega. You’re light. I have a hot temper. I only hope that you are not now so angry with me that I cannot come to visit your daughter.”

Jofre Tarrega smiled unexpectedly, and then placed his hands gently on Galileo’s shoulders.

“You are always welcome in my house, Leo.”

Soon after, as Galileo took his leave from Tarrega’s house, he became aware that he was being followed. Twice he heard footsteps on the paving stones behind him — footsteps which stopped whenever he did. He quickened his steps, determined that he would lead his follower an exhausting chase. He kept to. the broad avenues in a north-easterly direction, and passing the university came at last to a broad piazza where three lofty buildings, built of fair marble, rose like giant ghosts in the moonlight — the Duomo, the Baptistry, and the Leaning Tower.

Galileo, satisfied that his follower was still behind him, crossed a grassy corner of the piazza, passed the Leaning Tower, and entered the Campo Santo, the cemetery adjacent. Once in the concealing darkness he pressed himself against a wall and waited. Footsteps sounded, and as a man passed by him, Galileo spoke up sharply.

“Why are you following me?”

The man spun around, whipped out a dagger from his belt, and pressed the point against the young professor’s chest..

“Diavolo!” the man whispered. “I should kill you now, Galileo Galilei. But take heed of my words, or I shall do it later, I swear!”

“What have I done?” Galileo demanded. “Why do you threaten me?”

He could see now in the moonlight that the man was young, tall, and strong, and that he wore a mask over the upper part of a gaunt face. Then, when his attacker whispered again, Galileo thought the voice sounded familiar.

“You will not visit the house of Livia Tarrega again!” the masked man cried.

“Why not? I respect and admire the signorina.”

“Do you? That is why, I suppose, you visit her secretly at night, creeping along the back street, and atop the wall to her window.”

“But I have not — ever!” Galileo protested. “I visit the signorina with her father’s full permission, and always in the presence of her duenna.”

“You lie! My friend has seen you at her window.”

“Then your friend it is who lies. He wishes you to make a scandal, perhaps kill me — for something I have not done, nor, I vow, has anyone. The signorina would not permit anyone to visit her thus. Surely you could not love her and think that she would do such a thing!”

The sincerity of Galileo’s speech had an effect upon the young man. The pressure of his dagger point upon Galileo’s breast lightened, and he spoke only once more.

“Perhaps you are telling the truth. I hope so. But keep away from Livia Tarrega!”

And he was gone.

Quite unexpectedly, Galileo recognized his attacker the following day as he stood upon the banks of the Arno amid cheering crowds, watching the Giuoco del Ponte, or the Fight for the Bridge.

Once each year Mezzogiorno (that is, Pisa south of the Arno) challenged Tramontana (Pisa to the north) to fight upon the Ponte di Mezzo, the object being for the “fighters” of each side to penetrate to the opposition’s half of the bridge.

Now as Galileo watched, each of the battalions assembled on its side of the river, and at the sound of a horn from the marshal, they rushed forward to meet in combat upon the bridge, armed, and in helmet and breastplate. One young fighter on the Tramontana side caught Galileo’s eye at once. In his helmet, which descended low like a mask, he was instantly recognizable as Galileo’s pursuer of the night before.

Galileo kept his eye upon him all through the fight, and when the marshal blew the horn which terminated the struggle, he saw him break away from the cheering crowds and set off by himself down the narrow lane of La Cervia. Galileo followed at once, and catching up with him, tapped him upon the shoulder.

“Oh, it is you,” the young man said, removing his helmet and turning a sullen face towards the professor.

Galileo blinked with surprise. It was Paolo Salviati, who attended Galileo’s course in mathematics — an outstanding student of law who was in his final year at the university.

“I never met you visiting at Signorina Tarrega’s,” Galileo said at last.

The other shrugged, as if scorning a denial.

“And now that you know who I am,” he said, “What will you do?”

Galileo sat down upon the edge of a small marble fountain and folded his arms.

“I shall say nothing to anyone about the incident — provided you tell me who it was that told you the lie about me, that I visited the signorina secretly.”

“I cannot do that.”

“Then I shall report the matter to the rector.”

“No, no I If it is known I assaulted a professor of the university, I shall be turned out, and all my work shall be for nothing!”

“Then tell me.”

The young man clenched his fists and looked for a moment as if he might attack Galileo again. But finally he said, “It was one of the other professors. But do not ask me his name—”

“A colleague! Will one descend that low to stem the flow of truth from my rostrum? You must tell me his name, Salviati!”

But shaking his head, the law student hurried off down the lane.

Two nights later, as Galileo lay sleeping in his small house close by the university, he was awakened by a thump on the wall. He lay listening, but all the sounds he could hear were the distant clop-clop of a mule’s hooves on the paving stones and, from the inn next door, the Padrona talking out loud in her sleep again. But the memory of the thump disturbed him, so presently he rose, lit a candle, and opened the street door.

He saw at once it was empty, and smelled the odor of fresh fish that always blew from the river at this hour. Then, as he turned to close his door, he espied the note upon the sill.

You are warned again — do not break idols in the market place!

Galileo crumped the note in his hand. He looked again up the street as he heard the sound of singing which grew louder and louder until he recognized the voices.

“Vincenzio — Pettirosso,” Galileo cried. “What are you doing here so late?”

Two of his most trusted and promising students appeared out of the shadows and smiled affectionately at him. One of them carried a jug of wine.

“You look troubled to-day, maestro, and we thought you might need cheering up,” said the smaller student, who was called Pettirosso because he was preternaturally fragile-boned and light, like a bird.

“Well, perhaps you are right,” Galileo said. “Come in.”

And while his visitors sat down at the table, the young professor fetched three pottery cups and poured wine freely all around.

“This was just left at my door,” Galileo said at last, throwing the note upon the table. “Did you see anyone upon the street?”

“Not a soul, maestro,” Pettirosso said, reading the note and passing it to Vencenzio. “Who do you think wrote it?”

“At first I thought it was an outsider, but now I think it was a member of the faculty.”

“And why should anyone write thus?”

“The faculty resents the fact that my statements do not accord with their venerable Aristotle’s.” Galileo smiled suddenly. “Tell me, Vincenzio, what do you think I should do? You’re the bold one!”

Vincenzio Barbierini rubbed his hands and scowled. He was a broad fellow, handsome, with long blond hair that curled over his collar. Although he was often vain and given to preening himself over his accomplishments with the meretrices, or loose women of the city, to Galileo he showed only respect and devotion. Indeed, Vincenzio so admired his master that he set himself to copy not only Galileo’s forward-thrusting, inquiring air, but his blunt, uncompromising speech as well.

“You should punish this professor,” he said at length. “I tell you what, maestro, my good companion Pettirosso, who is like my own brother, and I — we will watch first this professor and then that one, and when we find the guilty one, we will tell you.”

“No, no,” Galileo said quickly. “It is better the writer remains anonymous, for if I knew his identity I might be rash enough to attack him.”

“Then what will you do?” Pettirosso asked.

Galileo drained his wine cup before he answered.

“I think,” he said, “I will make a public demonstration. That will teach them they cannot intimidate me with warning notes. Heretofore I have discreetly kept my proofs within the classroom — but now all Pisa shall see the great Aristotle proved wrong in broad daylight!”

“The experiment of the wooden balls!” Vincenzio exclaimed.

“Esattamente! But we shall use iron shot this time — a one-pound shot and a ten-pound shot, and we shall drop them from somewhere high — at least two hundred cubits.”

“From the Baptistry?”

“No. From the Leaning Tower.”

The word of the projected experiment travelled fast. The very next day the rector of the university called Galileo to his chambers, and fingering his white beard he spoke reprovingly.

“Galileo Galilei, I have heard of the public demonstration you plan for next week. Is this wise?”

“Why, sir, when I came here, did you not encourage me to disperse ignorance with the light of truth?”

“True, my boy. But have you never heard that it is dangerous to break idols in the market place?”

Galileo stared at the rector, scarcely believing his ears. Then he pulled the latest note from his pocket and laid it before his superior.

“Did you write this, sir?”

The rector read it with raised eyebrows, and then murmured, “My words were almost the same, weren’t they? But I must have heard someone say them. No, I did not write it, but I would say it is a just warning, against which it would be foolhardy for you to proceed.”

“And do you only warn me, too, sir?” Galileo asked. “Or do you forbid me the right to demonstrate my own discoveries?”

The rector sighed. “No, Galileo Galilei, I cannot do that. You may go ahead with your demonstration if you like, but take care you do not see your hopes buried in the holy ground of the cemetery of Campo Santo!”

The rector’s words echoed in Galileo’s ears on the day of the demonstration, as he stood upon the piazza adjacent to the Campo Santo, waiting for the bells of the Leaning Tower to strike the hour of noon. But he tried to be confident. Hadn’t he and his assistants — just before dawn, while all Pisa was sleeping — conducted the experiment from the tower exactly as he planned to do it today? It was true that someone had probably watched them, since Vincenzio claimed he heard footsteps from the cloister of the Duomo, but nothing had come of it.

Now, with the sun almost at its zenith, professors stood lounging about the square talking and laughing, many of them casting derisive or hostile looks in Galileo’s direction.

Townspeople who doubtless expected some kind of spettacolo were also present — mothers and their small children, idlers, and keen-faced priests whom Galileo hoped were Jesuits, since there were fine scientists among them. In the crowd he espied the gentle old rector and, sitting upon a stone bench close by, in the shade of the Duomo, Giovanni de Medici, his arrogant lips curved in a sneer.

The bells in the tower began to ring twelve o’clock, the laughter and stirring ceased, and all eyes were turned upon Galileo. He waited, however, until the last whisper of the bell tones had faded, and the bell-ringer himself had stepped out through the single, high door at the base of the tower and joined a young man whom Galileo recognized as Paolo Salviati. Then Galileo raised his hands and spoke in a loud clear voice.

“See here, each of my assistants holds an iron ball.” He pointed to Vincenzio and Pettirosso behind him. “One iron ball weighs one pound, the other ten pounds. We shall carry them to the top of the tower and drop them down upon the area below the leaning side, which we have roped off. You who are disciples of Aristotle believe that falling bodies of unequal weight, if dropped from the same height at the same moment, will reach the ground at different times—”

“That’s right,” de Medici called from the crowd, “and the heavier body travels in proportion to its weight.”

“I deny this is true,” Galileo said, “and shall demonstrate the fallacy of Aristotle’s reasoning. Watch!”

Amid a sullen murmur, Galileo strode into the tower followed by Vincenzio and Pettirosso and the trio climbed the six, successive circular staircases which coiled dizzily around a core of empty space and ropes from the belfry.

Reaching the topmost gallery, above which loomed the bell tower itself, Galileo paused to catch his breath and noticed that Pettirosso alone had followed him.

“Where is Vincenzio?” he demanded.

“He’ll be right along, maestro,” Pettirosso assured him. “He stopped to look out the lower gallery door. Woman trouble! He thinks she did not come to see him perform to-day!”

“Vincenzio!” Galileo called. “We have no time to waste!”

The next moment his heavy-set assistant panted up the steps, and indeed he did not look well. There were dark rings under his eyes and his handsome face looked pale.

“I told you, Vincenzio, you should not have exerted yourself last night,” Pettirosso said with a laugh.

“Silence!” Vincenzio roared, then bowed subserviently to Galileo. “I’m very sorry, maestro. I am ready.”

Galileo took from the pocket of his gown two square silk nets, and laying them flat upon the gallery floor, he carefully placed an iron ball in the center of each. Then grasping the corners of the nets, he suspended a ball from each hand, and stepped forward to the marble parapet. Vincenzio seized him firmly by the ankles, and Galileo leaned forward until he could see the crowd far below.

“Now watch!” he called down in the still, noon air.

He held out the balls, and when his hands were on an even plane he released them at the same instant. Down they plummeted, the silk nets floating off almost invisibly while the balls grew smaller as Galileo watched them; then for an instant they too seemed to disappear, and he saw two simultaneous puffs of dust as the balls struck the earth.

“We have done it!” he said, smiling to his assistants, and pointed to another pair of one-pound and ten-pound balls upon the floor of the gallery. “Be ready with them.”

Galileo hastened down the steps of the tower, half expecting that some of the spectators would come up to congratulate him; but he met not a soul, and when at last he came out through the tower door the old round-shouldered bell-ringer, who sat upon a bench a little distance away, looked at Galileo incuriously.

“It’s impossible!” Galileo murmured. “Don’t they understand?”

But already the greater part of the crowd had wandered away from the piazza, clearly disappointed by the exhibition, and as Galileo rounded the tower to the roped-off area, he saw that only a few of the professors and students remained. He looked up and saw Pettirosso and Vincenzio leaning over the balcony — doubtless they, too, were disappointed in the lack of reaction.

“Look, then,” he cried to the little group, “did not the bodies strike the ground at the same moment?”

Two of the professors came over and shook Galileo’s hand.

“Indeed, my boy,” said one, “You have proven your point. You have won our admiration.”

Galileo turned to the others.

“Are there any of you who have questions? My assistants are ready to repeat the experiment at once.”

Nobody seemed to have any questions. Disappointed, Galileo looked up at his assistants on the tower and started to give the prearranged signal for quitting. Instead he uttered a startled shout.

For at that moment both students seemed to lose their balance — they slipped over the parapet and came diving down headfirst. There was plenty of time to observe the difference in their sizes — Vincenzio, full-fleshed and heavy, Pettirosso, small and bird-like.

And once again two bodies struck the earth at the same instant.

Galileo was sitting at his supper table that evening, unable to eat a morsel, when a messenger from the university brought word that the rector wished to see him.

The young professor found the rector behind his desk, looking grave in the dark robes and fur-trimmed hood of his office. Through the windows opening on the courtyard sounded a chorus of students’ voices chanting:

“Grillo, mio Grillo,

Se tu vo’ moglie dillo...”

“Many in the town believe the Devil hurled your assistants over the parapet,” the old man said. “You yourself ran up to the tower directly after their fall; after stationing students at the tower door to see that no one escaped. Your inquiry was most thorough, I recall. The bell-ringer Aproino says that no one passed him all the time he was watching.”

“He must have left his post when the accident happened,” Galileo said, a desperate note in his voice.

“It could only have been for a moment or two — not long enough for anyone to descend the six flights from the top and escape. To make it worse, Aproino claims he heard the Devil stamp his foot.”

“You don’t believe that!”

“I am merely reminding you of the forces arrayed against you. There is bound to be an official investigation, and I fear you had better he able to explain what happened on that tower.”

“I told you, my dear rector. They merely leaned too far forward and fell. When I was up there, I had Vincenzio hold my ankles because I, too, felt the downward pull.”

“Both of them fell together — accidentally?”

“Why not? One could have tried to reach out to save the other—”

“Did you see one of them reach out? I stood by your side, and I failed to. The other witnesses say they did not merely fall over the parapet — they were thrown!”

“They imagine it — there was no one in the tower except my two assistants!”

“Do you really believe that, Galileo Galilei? Then what became of the second set of iron shots?”

Galileo gasped. “How did you know?”

“Do you forget that I followed you up to the gallery? I looked for the second set, because only a few moments before you said your assistants were ready to repeat the experiment. That meant they must have had duplicate shots in the tower. Is that not true?”

“It is true,” Galileo admitted.

“Then you will have to explain to the authorities what happened to them. Many will say the Devil took them. You will have to prove he did not, and you know that I cannot lie in this matter.”

Galileo passed his hand nervously through his red hair. “Perhaps if I knew where the sand came from...”

“Sand?”

“Scattered on the floor of the gallery. It wasn’t there the first time I went up — I can swear to that!”

“You have only a day or two to think about it — the time it will take authorities to travel from Florence. I warned you that flaunting your discoveries in the faces of your colleagues might end disastrously. Now you must pay for that flagrancy.”

“I will find the one who did it,” Galileo said, his voice shaking.

“For your own sake, my boy, I hope you do.”

Leaving the rector’s chambers, Galileo walked the streets for a long time with despair in his heart, coming at last in front of the Duomo. There he watched an old woman come out of the church, stop, then go back and rub the dark-green bronze doors where a little lizard in bas relief shone like gold. Hundreds rubbed the spot every day, considering it lucky, and Galileo sighed, wishing that he were credulous enough to comfort himself so easily. But talk might help him to see a light. He turned his steps in the direction of Jofre Tarrega’s.

A knock on the door brought Guilia, but this time the woman did not welcome him.

“Signor Tarrega has been ill all day,” she said sternly, “but he said he would speak to you himself. Wait here.”

His heart numb, scarcely believing his ears, Galileo stared at the closed door, until it opened again. Jofre Tarrega stood before him.

“I’ve been expecting you,” Tarrega said, coldly ironical. “The rector has told me the news. What proud triumph you must have felt when you let go those nets and saw the two iron balls hit the ground at the same instant! But such hubris calls down its own destruction, and you have brought ruin upon yourself. I wash my hands of you, and so docs Livia, who returned from Lucca in time to hear of this fiasco. You are no longer welcome in this house.”

Galileo departed without a word and walked back the way he came. As he crossed the market place he came face to face with Giovanni de Medici. The young prince looked at him haughtily and laid his hand negligently upon his sword.

“Look at you now, Galileo Galilei — you are as mired as my machine at Leghorn! How much longer will you strut to your classes, amico?”

The prince’s malice was like a dash of cold water. Galileo took a deep breath, and his mind took firm rein over his emotions.

He tried to pass on, but de Medici caught hold of his arm.

“Listen,” he whispered, “I want you to know this, and it shall remain just between us. You can thank me for your predicament. I wrote those notes!”

“In Heaven’s name, why?”

“I trusted to your hotheadedness. I knew that if you thought someone of the faculty wrote them, you would be sure to make yourself even more unpopular with some ill-considered defiance.”

Instead of anger, Galileo felt only a curious relief. For now his course lay clearly ahead of him. He pulled himself away from de Medici’s grasp.

“Then I have much work to do to mend the results of my own folly,” he said softly.

Galileo went at once to the bell-ringer’s small stone house, just outside the walls of the Campo Santo, and was admitted by the little man. Inside, at the fireplace, stood the law student, Paolo Salviati.

“Don’t look surprised, signore,” he said. “Guiseppe Aproino, the bell-ringer, is my uncle.”

“I’m in great trouble, Salviati,” Galileo said. “I wish to ask your uncle some questions, but I’m afraid he resents my presence.”

“Uncle!” the young man said sharply. “You help the maestro, understand?”

The bell-ringer turned the palms of his hands upwards, and shrugged.

“Si, maestro?”

“I came to you before dawn this morning to ask for the keys to the tower, and returned them to you after the rehearsal. Has anyone else borrowed them since?”

“No, maestro.”

“But the door of the tower is left open during the day?”

“Si. I open it at sunrise, when I ring the first bells, and close it at sunset when I ring the last.”

“And are you there all the time?”

“No, no. Between sunrise and noon I work in the gardens.”

Galileo nodded with satisfaction. “The rector says you heard the Devil stomp his foot.”

“Si — twice I heard him.”

“Twice?” Galileo paused, frowning. “Did you see me throw the balls from the tower, Signor Aproino?”

“No. A little girl ran into the tower and I went after her. I was inside when the Devil stomped.”

“Now think carefully,” Galileo said. “When did you hear the Devil stomp the second time?”

The bell-ringer scratched his chest thoughtfully. “Not much later.”

“Before I came down from the tower?”

“No, just afterwards. I remember I was sitting on the bench outside.”

“Before the students fell from the tower?”

“Si, before that.”

“One more thing. The rector said that when the students fell from the tower you did not leave the door untended. But did you not run to see them?”

“The poor ragazzos? Si! But always I am in sight of the door. Nobody comes out, I swear! It was the Devil who pushed them — the Devil!”

Galileo bowed formally. “Thank you, Signor Aproino. I would like now to examine the tower again — with your permission.”

The bell-keeper frowned.

“I will take him, Uncle,” Salviati said.

The old man grumbled and produced a large key, and the student, after lighting a lanthorn, led Galileo out of the house.

Inside the tower, which was far more draughty and dank in the night than in the day, they paused and looked at the maze of ropes that led upwards through the dark floor, but two of them were tied to cleats upon a heavy, solid oaken frame.

“Why are those ropes cleated?” Galileo asked.

“To distinguish them. This one leads to a bell that is rung only on feast days, the other to a cracked bell my uncle does not ring at all.”

Galileo seized the latter rope and gave it a tug. Nothing happened.

“It seems to be fastened,” Galileo said.

“To a bar in the belfry — so that my uncle does not ring it by accident.”

Galileo took the lanthorn from Salviati and led the way to the top of the tower where, his feet gritting on sand, he started a slow circuit of the gallery.

“May I ask, maestro, if you think Vincenzio and Pettirosso were murdered?”

“I know it.”

The law student was silent a moment, then he said, “Two others came to-night to ask for admittance to the tower.”

“Who?”

“The rector, and Giovanni de Medici. Uncle had to oblige them, and he climbed the tower with them. All they did was to walk round and round the balcony. De Medici seemed certain the Devil had been here.”

“Ah,” Galileo exclaimed suddenly, and holding his lanthorn close to a narrow gutter that drained the gallery, he plucked from the channel a small piece of thin leather.

“That tells you something, maestro?”

Galileo nodded, then rose quickly and ascended the iron ladder that led up into the belfry, where his lanthorn winked fitfully as he stepped among the dark shapes of the bells. A little later he descended.

“I’m ready to go now,” he said.

The professor and the student walked back to the bell-ringer’s house in silence, and as they were about to part, Galileo held up the lanthorn.

“I’d like to borrow this, Salviati. I have much yet to look for tonight.”

“Of course. But where do you go?”

“To the Campo Santo.”

“But what will you do in the cemetery?”

“Search.”

“You may be in danger, I think. Let me come with you.”

Galileo looked keenly at the gaunt face of his companion.

“Last week you pressed a sword to my chest, Salviati. Why now do you offer to befriend me?”

“You might have told the rector about my attacking you, and yet you held your tongue.”

“Very well,” Galileo said after a moment. “You may come along.”

The moonlight was bright upon the urns and effigies in the cemetery, the grass soft and springy underfoot — grass growing from sanctified soil that had been brought in shiploads from the Holy Land. Galileo threaded his way among the graves and stopped finally in the shadow of the Leaning Tower.

“This would be the area, I think.”

“What are you looking for?”

“The second set of iron shot.”

Galileo searched until finally he discovered a hole in the turf, and embedded in it, the ten-pound shot. A few feet farther away he discovered the one-pound shot. He lifted the latter gingerly and examined it by the lamplight. Suddenly he pointed to some brownish stains on the surface of the iron ball.

“Blood.”

“What does it mean?”

“It demonstrates the truth of my reasoning. Listen. Before dawn this morning, the murderer watched our rehearsal — we heard his footsteps in the Duomo — and he knew exactly what we were going to do. At sunrise, just after your uncle left to do his gardening, the murderer crept into the tower and hid himself in the belfry. At noon he watched me drop the two iron balls. Then after I left Vincenzio and Pettirosso at the top of the tower, he came out of his hiding place and struck the two students from behind with a sandbag he had brought with him. He must have succeeded in stunning little Pettirosso at once, but with Vincenzio, the larger one, he had trouble. His sandbag burst open in the struggle — I found a piece of the bag in the gutter a while ago. He managed to seize the smaller iron ball and struck Vincenzio’s head—”

“But we found no blood on the balcony.”

“He smugged it out quickly with the spilled sand. Then, with Vincenzio and Pettirosso both unconscious, he propped up their forms against the parapet, keeping himself well concealed. When I reached the ground and looked up to see my two assistants leaning over, they were already unconscious.”

“But why did he throw the second set of balls from the tower?”

“To make the crime look supernatural. Look what he does now! He runs to the opposite side of the tower, overlooking this cemetery, where there were no spectators, and tosses the balls down. The impact of their hitting the earth was the second sound of Devil’s hooves that your uncle heard. The first thump, of course, was the landing of my own shot.”

The law student held up His hands in objection.

“Then the murderer pushed Vincenzio and Pettirosso over the edge?”

“Yes.”

“But how can someone throw away shot and push men from the tower and then totally disappear? My uncle said no one came out, and you searched the tower from top to bottom immediately after.”

“He escaped, of course, during the only few crucial seconds when it was possible — when everybody’s attention was drawn to the falling students!”

“But he wouldn’t have time!” Salviati cried. “After pushing over your assistants, he would have to run down six flights of stairs. By the time he reached the ground, the first shock would be over, and my uncle would be watching the door again.”

“True, but right after the murderer pushed the two bodies over the edge, he slid down the rope that led to the cracked bell, the rope which your uncle had fastened to a stationary bar. Doubtless the murderer had come prepared to tie a rope thus himself, but your uncle had unwittingly provided just what he wanted. It would have taken him only seconds to descend. Everybody, including your uncle, was still absorbed in the spectacle of violent death, and the murderer was able to walk out of the tower unnoticed I”

“But maestro — who is he?”

Galileo stiffened as from somewhere in the city a dog howled in the night. Then he quickly replaced the one-pound shot in its recess in the earth and blew out the lanthorn.

“We now have a chance of catching him,” Galileo said. “He will not dare leave these shots in the ground. Come, let us hide behind the hedge yonder!”

Galileo and his companion crouched low in the protecting shadow and waited. Time passed slowly; the moon swung lower in the hazy sky, and the shadow of the Leaning Tower crawled imperceptibly across the graveyard.

About midnight, as Galileo judged, they heard the swish of grass and a shuttered lanthorn, with one panel open, glimmered near-by.

The mathematician waited until the searcher had found the smaller iron ball and placed it within a bag. Then Galileo stepped forward.

“You won’t get a chance to use it again,” he said loudly.

For a moment the man was immobile; then as he tried to escape, Galileo lurched forward and pulled him to the ground. Salviati seized the lanthorn, opened all the shutters, and held it close to the man’s face.

It was Jofre Tarrega.

“I knew you murdered my two students when I left your house earlier this evening,” Galileo said, while Tarrega sat tight-lipped upon the coping of a grave. “You said then how proud I must have been when I released the nets and heard the iron balls strike the ground at the same time. But nobody on the ground could have seen those nets at the height at which I used them, especially with the noon sun in his eyes. That meant that cither you, or the one who told you about it, was near me, in the belfry, watching the experiment from there. But the rector, who told you the news, was on the ground the whole time — so it could only have been you in the belfry!”

Tarrega growled. “I came here to investigate — to help you, Leo. I had nothing to do with the two deaths.”

“Signor Tarrega,” Galileo said quietly. “You can no longer keep your secret.”

“What do you mean?”

“The professor who told Paolo Salviati that he saw me enter your daughter’s room thought he was telling the truth. I’m sorry to say this, signore, but my whole life’s work is at stake. Livia permitted Vincenzio Barbierini to enter her room at night. Vincenzio’s stature is similar to mine, and his fair hair might look red in the moonlight. Also, he often affected many of my gestures and mannerisms, and could well have been mistaken for me by the professor who saw him.

“Last night Vincenzio visited Livia again. Doubtless you found out about it and went looking for Vincenzio. You saw us rehearsing in the tower and the plan of the murder of Vincenzio occurred to you. You knew how Vincenzio boasted of his conquests and you could not bear to let him defame your fine name or your daughter. So you killed him — and Pettirosso, too, because he was present and could have denounced you.”

Tarrega’s shoulders drooped and suddenly his face looked old — very old.

“Shall we go to the rector now, signore?” Galileo asked.

Without a word Tarrega rose to accompany them.