As they continued not finding a living man, Jean-Claude’s investigation took on greater importance. The other members of the keel gang were the most helpful in that they actually had memories of the missing man, though none of them could recall precisely when they’d last seen him. They agreed he’d been to chow because it was Saint Even’s Day and nobody missed out on the lemon tarts, even if they were old and dry. They were pretty sure he’d gone back to his rack, but they weren’t sure when he’d got up and left. He had a journal that he wouldn’t show anyone, and sometimes he’d go wander the turvy deck, and when he wasn’t doing that, he was usually in the workshop tinkering with used parts. He didn’t gamble, and as far as they knew he didn’t owe anybody so much as the time of day.

Jean-Claude opened Gephardt’s sky trunk and inventoried the paltry findings: an extra set of clothes, books on aeromechanics, small tools, a very well-used journal. He picked up the worn leather book and flipped to the most recent page of entries.

Gephardt’s handwriting was small and neat, so as to fit more words per page. The keelmate mentioned his assignment to the Thunderclap, noted his signing bonus, and then sketched a design for something labeled an aetheric condenser valve, beside which were scratched equations Jean-Claude was unqualified to decipher.

He closed the trunk, fastened it with his own lock, and then sought Isabelle. He found her on the quarterdeck directing the search under cerulean skies. The upper airs had been scrubbed clean and the Miasma below beaten down, leaving nothing but the coppery scent of the deep sky.

Her skin was pale with fatigue and her expression drawn. She gave him a tired smile. So far she had her ghosts under control, but he dreaded the day she looked at him without recognition. She was the child of his soul if not his seed. It was not fair that she should be afflicted by a foe he could not fight, one that attacked the very root of her being.

“Have you learned anything new?” Isabelle asked.

“Nothing useful,” Jean-Claude said. “The most pervasive hypothesis is that he exited the ship by way of a turvy hatch and fell into the Gloom. The follow-up question is whether his departure was accidental, coerced, or voluntary. An odd man with no friends, he may have had cause for despair.”

Isabelle grimaced. “I can understand that. Bullying is murder by subtle means.”

Jean-Claude handed her Gephardt’s journal. “He was working on something numerical that I can’t understand.”

Isabelle pulled on her gant d’acier to hold the book with her spark-hand while she thumbed through it with her skin hand. She got to the end, shook her head, and said, “Poor man. He was trying to work out the Maddux-Creech conjecture.”