The three basswood planks were no longer bare timber. They had become a battlefield of white lines, force vectors, and exact tolerances. Ivara Quill worked with the short stub of a red grease pencil she had taken from Urel’s vest pocket, her single hand moving across the grain with the feverish care of a woman who knew that an error in arithmetic meant thirty thousand people burned in their beds.
Outside the kitchen bay, the damp railway shed seemed to hold its breath. The distant whistle of an empty coal train shunting on the south loop sounded thin and muted through the brick arches, like a cry through wet wool. On the platform, two women from the laundry shed were tearing old cotton bedsheets into three-inch bandage strips, boiling the cloth in a copper wash-boiler to prepare for the burns that everyone knew were coming.
“Look at the cooling line,” Ivara commanded. She tapped the grease pencil against a two-inch channel drawn parallel to the main discharge tube. “Morn’s original blueprint relied on a backup water jacket made of eighth-inch rolled copper sheet. He pumped canal water through it at fifteen pounds of pressure.”
“Fifteen pounds is useless,” Urel said, leaning over her shoulder with his ivory scale. “At fifteen pounds, the boiling point of water is two hundred and thirteen degrees. The moment the solar star-fire hits the internal baffle, the heat transfer through that eighth-inch copper will flash the water inside the jacket to dry steam in four…
