The Crystal Palace at full capacity was a different building than the Crystal Palace at setup.

She had been in it yesterday with the ambient noise of installation and the particular smell of a space being prepared — sawdust and metal and the specific compound of concentrated human effort that accumulated in any space where many people were working toward a common deadline. Today it smelled of the crowd: thousands of people in their best clothes, the layered perfumes and colognes of a city's social apparatus deployed for public display, the specific heat of many bodies in a glass-and-iron building on an autumn morning that was warmer than expected.

She stood at the entrance to the third gallery and took stock.

The Crystal Palace on the day of the Exposition was Florence at its most distilled: every social layer present, every institutional interest represented, every personal ambition that had attached itself to the question of what was worth making and what was worth rewarding gathered under a single vast roof of glass. The international jury was visible from here — a group of twelve, moving through the galleries with the specific quality of people who were being watched watching, aware that their responses were data that Florence was collecting.

Raymond was already at the exhibition space when she arrived. He had been there since seven, he told her without particular emphasis, which meant he had been there for two hours before the doors opened, which meant he had slept less than she had, which was itself notable since she had slept approximately four hours.

"You've adjusted the humidity calibration again," she said, looking at the governor mechanism's secondary setting.

"The internal temperature is three degrees warmer than the test day. It affected the compound's volatility curve by a margin I wanted to correct before the presentation." He looked at the setting. "The adjustment is within the specified range."

"I know it is. I'm noting that you made it."

He looked at her. "Should I not have?"

"You should have. I'm noting it because I would have noticed it and you were already here and now I don't have to do it." She sat at the equipment table. "That's the fourth time this week you've solved a problem before I identified it."

"The third," he said. "The transport cases were your solution."

"The transport case latches were yours. I solved the case geometry."

"The latch specification was in your original brief."

"The brief said secure closure. You specified the latch mechanism."

He looked at her with the expression that was not quite a smile but occupied the same territory — the expression she had come to think of as the one he had when she was doing something he found specifically her. "Are we attributing the latch mechanism?"

"We are establishing accurate credit allocation for the project record."

"Then the latch mechanism was collaborative."

"Noted," she said, and wrote it in the equipment log, and the morning settled into the particular quality of two people who were managing their nerves through precision.

The gallery opened to the public at nine.

The first two hours were navigational. She moved through the space, connecting with people she recognized — the German judge she and Raymond had met on the first morning, several colleagues of her father's who had come specifically to see the machine, a journalist from a Turin paper who wanted background on the project's history. Raymond stayed near the equipment, which was correct: the machine required someone with technical knowledge present at all times, and crowds at the machine were better managed by the person who had built the compound system rather than the person who had built the housing.

But she found herself aware of his location.

Not anxiously — not the way she had been aware of threat locations during the Valois masquerade, the vigilant tracking of Viviane's position and Leonard's position and the compound density in various parts of the room. This was different: a low-level continuous awareness that she was learning to recognize as the way she was going to be aware of him, probably, for the foreseeable future. The way you were aware of a compass bearing — not requiring constant conscious attention, simply always available when you checked.

At eleven o'clock she was in conversation with a cluster of Academy-adjacent academics who had approached her with the specific quality of people who were deciding whether to be impressed before they had completed their impression formation, when she registered, peripherally, that Raymond had been engaged by a group near the machine and that the group's composition had changed in a way that required monitoring.

Leonard was in the group. Not at its center — at its edge, in the position he used when he was listening rather than leading, which was more dangerous than his leading position because it was harder to track.

She excused herself from the academics — smoothly, with the social competence she had developed over twenty-two years of navigating Florence's drawing rooms — and crossed the gallery.

The group contained two people she recognized as northern investors, one she identified as a member of the Exposition's technical committee, and Leonard. Raymond was talking — answering a technical question about compound behavior in varied atmospheric conditions, the kind of question that was either genuine curiosity or a probe for weakness, and that Raymond was handling with the precision he brought to all technical questions, which was to say completely.

She arrived at the edge of the group.

Leonard's eyes moved to her. His expression did not change in the way that expressions didn't change when they had been prepared not to change.

"Miss de Monet," he said, with the warmth of someone who had decided warmth was the correct register. "We were just discussing the atmospheric variables affecting compound volatility. Mr. Vance has been very generous with the technical detail."

"Mr. Vance's command of the technical detail is what makes the machine work," she said. She looked at the technical committee member, who was a small precise woman named Ferrara who she knew slightly from the Academy's public lecture series. "Dr. Ferrara — I believe you had questions about the calibration methodology?"

Dr. Ferrara had questions about the calibration methodology. Raymond answered them. The group reconfigured around the technical content rather than the social geometry Leonard had been constructing, and Leonard drifted toward the gallery edge, and after ten minutes the investors had photographs and Dr. Ferrara had notes and the group dispersed.

Adeline stood beside Raymond near the machine.

"Leonard," he said, without inflection.

"I noticed."

"He was positioning the investors to hear about the project in a specific context. Before the presentation."

"I know. Dr. Ferrara's questions redirected the context." She looked at the machine. "You handled it well."

"You handled it," he said. "I answered questions."

"I provided the questions that needed answering. You answered them in a way that made the technical committee member want to take notes." She looked at him. "That's collaborative."

The corner of his mouth moved.

At twelve-thirty she found herself in the far corner of the third gallery with a glass of water and a moment of quiet, the specific quiet of someone who has been navigating a demanding social environment for three hours and has found a temporary gap. She looked across the gallery at the machine in its exhibition position — the machine that had been in her mind as a concept for three years, that had been on her bench as a construction for three months, and that was here now, complete, in the Crystal Palace, being looked at by people from six countries.

She looked at Raymond, who was at the equipment station with a junior member of the international jury, explaining something with his hands, the specific gesture he used when he was describing spatial relationships in compound behavior — both hands moving in parallel curves that mapped the distribution of volatiles through a space. She had seen him make this gesture dozens of times in the laboratory and it always communicated, regardless of the content of what he was saying, the specific quality of a person who found what they were talking about genuinely interesting and expected you to find it interesting too.

The junior juror was leaning forward.

"He's very good at that," said a voice beside her.

She turned. Dr. Ferrara had materialized with her own glass of water and the expression of someone who had been watching the same thing from another angle.

"At explaining," Adeline said.

"At making people feel like the most interesting conversation they could be having is the one they're currently in." Ferrara looked across the gallery. "It's a specific skill. Rarer than people realize."

"Yes," Adeline said. "It is."

The afternoon approached. The presentation slot was at three. She returned to the exhibition space at two-thirty and found Raymond doing a final check of the compound series — not because it needed checking, because the hands needed something to do.

She stood beside him.

"Nervous?" she asked.

"No," he said. A pause. "Yes." Another pause. "The work is correct. The nerves are about whether the work will be received as correct, which is not the same thing and is not within my control." He looked at the compound cases. "I find that distinction difficult to maintain in practice."

"I know," she said. "Me too."

She looked out at the gallery, which was filling toward its afternoon capacity, the crowd thickening, the noise level rising, the Crystal Palace's light beginning to do its golden-hour thing with the afternoon sun coming through the west-facing glass.

"I'll be at the reception position," she said. "When the audience is in place, look at me first. Before you look at the jury. Before you look at anyone else."

He looked at her.

"You said that to me," she said. "At the masquerade. I'll be there. Look at me if you need an anchor."

Something moved through his expression — recognition, and something warmer than recognition. "I remember," he said.

"I know you remember." She picked up her presentation notes. "You always remember."