Doss rested his gloved hand on the probe at the copper radiator and did not take it away.
They had rebuilt the rig in an hour. A new test channel, bored by Gell on the yard lathe to the same radius as the first, and lined by Anwen with the second mirror iron sample: not along its surface grain, the way Mara had laid the first, but turned in the rotating fixture to thirty-one degrees and fixed there with a dab of high-temperature cement at each end, so that the working grain ran where the fixture said it should. Then the copper radiator clamped to its outer face, and the whole thing set back on its stand inside the sand walls, beside the scrap cell.
Mara had changed one more thing. Over the radiator, Doss had built a second, smaller sand wall: a box of shuttering boards filled with packed river sand, enclosing the radiator and the channel’s outer face entirely. A cover. If the return worked, the energy would come out through the radiator into the sand, and the sand would take it. If it failed, the sand would take that too.
Under the sand, the radiator sat in a shallow tray of water. Eshel had put a thermometer in the water and a pressure gauge on the cell’s feed, and run both lines out through the sand to his slate.
