In the rain-swept courtyard behind the Old Ferry warehouse. There, the cobblestones sloped toward the river wall, Eren Tal worked with four young apprentice carpenters by the yellow light of three storm lanterns. The air was filled with the clean, fragrant scent of white cedar sawdust, hot pine pitch. The bitter reek of boiled tea drifting from the back kitchen stove.
The filter box was taking shape upon four heavy oak skids. A six-foot box-shaped chest built of two-inch seasoned white cedar planks, held together with deep wood slot-and-wooden peg joints pinned with dried locust-wood trenails. No iron nails or steel bolts were used anywhere in the internal gas path. Korr Var, citing Hal Rook’s leather-bound field ledger, had insisted that iron bolts and pins would corrode to red rust within three days under the intense rotten-egg steam and drop loose scale into the lower air pipe hub.
Eren knelt on a damp sack of pipe lime, his heavy brass-bound framing square checking the corner angles. Meanwhile, his plane-iron shaved a long, curling ribbon of pale wood from the upper lid cleat. ‘Keep those shoulder joints tight as an oaken cooper’s cask, boys! Drive the oakum with the caulking mallet before you set the locust pins! When that foundry blower kicks on, we’ll have three inches of water-column static head inside this chest. If a single wood slot seam weeps, the acid steam will leak into the courtyard and crust every hinge in Sister Merrow’s pantry with sour burning acid.’
