The valve gallery ran along the well’s upper wall, above the pump hall, and nobody had walked it in forty years.
Sen’s crew chief had found the door the night before, behind a stack of empty cable drums at the pump hall’s north end. A narrow iron stair. At its top, a long low gallery cut into the rock, lit by a row of old glass lamps that came on, one by one, when Sen threw the switch at the stair head. Most of them came on. Three stayed dark.
The air smelled of dust and cold iron and, faintly, of old grease, as if someone had oiled the valves once and then gone away for good.
Along the gallery’s inner wall: valves.
Big ones. Each the size of a cart wheel, with a hand wheel on its face and a seal across the wheel: a strip of lead, stamped, wired through the spokes so the wheel could not turn without breaking it. Twelve of them, in a row. Each with a brass tag above it, green with age.
Mara walked the gallery’s length on the morning after the council, with the chalk question still at the top of the plate below. Sen beside her with the seal readings on a slate. Eshel behind with the gauge rack’s portable reader, a box on a strap round his neck, trailing a long cable back down the stair to the rack.
