Maud broke the induction loop in the tenth year, and did it on purpose, with permission, and it took eight months of argument to get there.
"It's failing anyway," she said, in the third council meeting on the subject. "Not the shaft — I fixed the shaft. The loop itself. The insulation on the buried run has been degrading since before I was born and there are four segments now where I can measure loss I can't account for by any other mechanism. In eleven years it fails on its own, badly, probably in winter, probably taking the undercroft supply with it."
"Then repair it," Wat said.
"I can't repair it without understanding it, and I can't understand it without taking a section apart, and Thomas built it fourteen years ago from a method that exists nowhere except in his head and about nine lines in the Codex." Maud, twenty now and entirely without deference, turned to Thomas directly. "Your own rule. You told Cecily the things you built fast and alone are the parts most likely to fail when nobody remembers why they're shaped that way. This is that. This is exactly that, and I'd like to fix it while you're still here to tell me when I'm wrong."
Thomas, who had been listening with a growing and complicated feeling, found he had no counterargument at all.
The complication was this: the induction loop kept the phone charged. It had done so for eleven years. It was the reason the battery had sat at ninety-odd percent through a decade in which everything else about the device had decayed. Taking a section of it apart meant, for however long the work took, no charge.
"How long?"
"Six weeks if it goes well. Four months if it doesn't." Maud didn't soften it. "And I'd want to change the geometry when we rebuild, because the original is — I'm sorry, but it's guesswork. It works. It's not designed. I can design it and it'll be better, but it won't be what you built."
"Do it," Thomas said.
The room, which had been arguing for eight months, went quiet.
"You've not asked what happens to your device," Alaric said carefully.
"It'll run down. Ninety-one percent, and it loses about two a week off the loop, so — a year, roughly, before it's dead." Thomas found this considerably easier to say aloud than he had expected. "The letters stopped two years ago. There's nothing coming in. I have a hundred and eighty saved messages to a woman who can't receive them and a number that's read one for three years without moving." He looked around the table. "It's a lamp I keep lit in a room nobody's in. Meanwhile there's a buried copper line under this town that supplies the undercroft, the fever house, and the schoolhouse, and a twenty-year-old who can make it better than I made it. It isn't a difficult decision. It only feels difficult because it's mine."
Victoria said nothing, but reached over and put her hand on his forearm and left it there for the rest of the meeting.
They cut the loop in the spring.
Maud's rebuild took eleven weeks, ran over her estimate by five, produced two failures she documented in exhaustive and unflattering detail, and resulted in a distribution system with roughly forty percent less loss than the original and — more importantly, as she pointed out repeatedly — a full written specification that any competent builder could reproduce from scratch.
The phone read seventy-eight percent when the new loop went live, and did not begin charging.
Thomas spent an afternoon determining why, and found it almost funny.
"Different geometry," he told Victoria that evening. "The old loop coupled with it by accident — I built it that way without knowing I was doing it, because I was working from a half-memory of induction charging and I got lucky. Maud's is properly designed and it doesn't couple with anything it wasn't designed to couple with." He turned the device over in his hands. "She built a better system and it costs me the only thing keeping this alive. Nobody could have predicted that. I couldn't have predicted it and I built the original."
"Are you going to tell her?"
"God, no." Thomas set it down. "She's twenty and she's just done the best engineering work anyone in this valley has produced in a decade, and I am not going to hand her a reason to feel guilty about it. It's a battery, Victoria. She rebuilt the thing that keeps a hundred and forty households in clean water."
He did tell her, eventually — four years later, when she was twenty-four and running the works and entirely secure in her own competence, and could hear it as an interesting technical detail rather than an accusation.
She was, by every account, furious anyway, and stayed furious for about a week, and then wrote a paper on unintended coupling in induction systems that was still being copied out of the Codex a century later.