Eshel wrote the reading on the board, and the time beside it, and read both aloud.
“Probe three,” he said. “Branch three, inner. Last valid reading.” The figure: the gradient along the channel wall, from the stepped lining’s inner edge to the body. “Twelve seconds old.”
He wrote 12 s beside it, and then, as he watched the rack’s clock, rubbed it out and wrote 14 s, and then 16 s.
“Getting older,” he said.
The room watched the number change. It was a strange thing to watch: a reading going stale on a board, second by second, while the thing it measured went on changing somewhere out of sight in the channel wall.
He put the chalk down.
“Too stale to run the quench alone,” he said.
He said it to the room, not to Mara, so everyone heard why. “The quench sets each stage by the probe. If I run branch three’s stages on a reading that’s a quarter of a minute old, I’m cooling the channel by what it was doing, not what it’s doing.” He looked at the figure. “Recent enough to bracket the value, though. If the neighbors agree with it.”
