Dr. Ryder turned white.

Bell said, “The Van Dorn Detective Agency’s Research boys root up the darnedest information. First Farmers of Pittsfield holds your mortgage, Dr. Ryder, the terms of which allow the bank to call in your loan if the value of the collateral plummets – as it has for most private asylums, including the Ryder Private Asylum for the Insane, as the new state-run institutions siphon off patients. I will meet with Miss Di Vecchio in a clean, pleasant, well-lighted room. Your personal quarters, which I understand are on the top floor of the turret, will be ideal.”

DANIELLE DI VECCHIO took Bell’s breath away. She entered Ryder’s cozy apartment tentatively, a little fearful – understandably, Bell thought – but also curious, a tall, well-built, very beautiful woman in a shabby white dress. She had long black hair and enormous dark eyes.

Bell removed his hat and gestured for the matron to leave them and close the door. He offered his hand. “Miss Di Vecchio. Thank you for coming to see me. I am Isaac Bell.”

He spoke softly and gently, mindful that she had been incarcerated under court order for slashing a man with a knife. Her eyes, which were darting around the room, drinking in furniture, carpets, paintings, and books, settled on him.

“Who are you?” Her accent was Italian, her English pronunciation clear.

“I am a private detective. I am investigating the shooting of Marco Celere.”

“Ladro!”

“Yes. Why do you call him a thief?”

“He stole,” she answered simply. Her eyes roamed to the window, and the way her face lit up told Isaac Bell that she had not been out of doors for a long time and probably not seen green trees and grass and blue sky even from a distance.

“Why don’t we sit in this window seat?” Bell asked, moving slowly toward it. She followed him carefully, warily as a cat yet aching to be caressed by the breeze that stirred the curtains. Bell positioned himself so he could stop her if she tried to jump out the window.

“Can you tell me what Marco Celere stole?”

“Is he dead from this shooting?”

“Probably,” answered Bell.

“Good,” she said, then crossed herself.

“Why did you make the sign of the cross?”

“I’m glad he’s dead. But I’m glad it wasn’t me who took life. That is God’s work.”

Doubting that God had deputized Harry Frost, Isaac Bell took a chance on Di Vecchio’s mental state. “But you tried to kill him, didn’t you?”

“And failed,” she answered. She looked Bell in the face. “I have had months to think about it. I believe that a part of my soul held back. I don’t remember everything that happened that day, but I do recall that when the knife missed his neck it carved a long cut in his arm. Here. .” She ran her fingers in an electric glide down the inside of Bell’s forearm.

“I was glad. But I can’t remember whether I was glad because I drew blood or glad because I didn’t kill.”

“What did Marco steal?”

“My father’s work.”

“What work was that?”

“My father was aeroplano cervellone-how do you say? – brain. Genius!”

“Your father invented flying machines?”

“Yes! Bella monoplano. He named it Aquila. Aquila means ‘eagle’ in American. When he brought his Aquila to America, he was so proud to immigrate to your country that he named her American Eagle.”

She began talking a mile a minute. Marco Celere had worked for her father in Italy as a mechanician, helping him build the aeroplanes he invented. “Back in Italy. Before he made his name short.”

“Marco changed his name? What was it?”

“Prestogiacomo.”

“Prestogiacomo,” Bell imitated the sound that rolled off her tongue. He asked her to spell it and wrote it in his notebook.

“When Marco came here, he said it was too long for Americans. But that was a lie. Everyone knew Prestogiacomo was ladro. Here, his new name, Celere, only means ‘quick.’ No one knew the kind of man he really was.”

“What did he steal from your father?”

What Marco Celere had stolen, Di Vecchio claimed, were new methods of wing strengthening and roll control.

“Can you explain what you mean by roll control?” Bell asked, still testing her lucidity.

She gestured, using her long graceful arms like wings. “When the aeroplano tilts this way, the conduttore – pilota-changes the shape of wing to make it tilt that way so to be straight.”

Recalling his first conversation with Josephine, Bell asked, “Did your father happen to invent alettoni?”

“Yes! Si! Si! That’s what I am telling you. Alettoni.”

“Little wings.”

“My father,” she said, tapping her chest proudly, “my wonderful babbo. Instead of warping the whole wing, he moved only small parts of it. Much better.”

Bell passed his notepad to her and handed over his Waterman fountain pen. “Can you show me?”

She sketched a monoplane, and depicted the movable hinged parts at the back of the outer edges of the wings. It looked very much like the yellow machine that Josephine was flying.

“Alettoni-hinged little wings – is what Marco stole from your father?”

“Not only. He stole strength, too.”

“I don’t understand.”

“My father learned how wings act to make them strong.”

In a fresh torrent of English peppered with Italian and illustrated with another sketch, Danielle explained that monoplanes had a habit of crashing when their wings suddenly collapsed in flight, unlike biplanes, whose double wings were structurally more sound. Bell nodded his understanding. He had heard this repeatedly in the Belmont Park infield. Monoplanes were slightly faster than biplanes because they presented less wind resistance and weighed less. Biplanes were stronger – one of the reasons they were all surprised when Eddison-Sydney-Martin’s Farman had broken up. According to Danielle Di Vecchio, Marco Celere had proposed that the monoplane’s weakness came not from the “flying wire” stays underneath the wings but the “landing wires” above them.

“Marco tested his monoplano with sandbags to make like the strain of flying – what is your word?”

“Simulate?” “Si. Simulate the strain of flying. My father said a static test was too simplistic. Marco was pretending the wings do not move. He pretended that forces on them do not change. But wings do move in flight! Don’t you see, Mr. Bell? Forces of wind gusts and strains of the machine’s maneuvers-carico dinamico-attack its wings from many directions and not only push but twist the wings. Marco’s silly tests took no account of these,” she said scornfully. “He made his wings too stiff. He is meccanico, not artista!”

She handed Bell the drawings.

Bell saw a strong similarity to the machine that Josephine had persuaded Preston Whiteway to buy back from Marco Celere’s creditors. “Is Marco’s monoplane dangerous?” he asked.

“The one he made in San Francisco? It would be dangerous if he had not stolen my father’s design.”

Bell said, “I heard a rumor that a monoplane Marco sold to the Italian Army broke a wing.”

“Si!” she said angrily. “That’s the one that made all the trouble. His too-stiff monoplano-the one he tested with sandbags back in Italy – smashed.”

“But why couldn’t your father sell his Eagle monoplano to the Italian Army if it was better than Marco’s?”

“Marco ruined the market. He poisoned the generals’ minds against all monoplano. My father’s monoplano factory went bankrupt.”

“Interesting,” said Bell, watching her reaction. “Both your father and Marco had to leave Italy.”

“Marco fled!” she answered defiantly. “He took my father’s drawing to San Francisco, where he sold machines to that rich woman Josephine. My father emigrated to New York. He had high hopes of selling his Aquila monoplano in New York. Wall Street bankers would invest in a new factory. Before he could interest them, creditors seized everything in Italy. He was ruined. So ruined that he killed himself. With gas, in a cheap San Francisco hotel room.”