Ballenberg
Zurich sawmill and bone mill, Graubünden linseed crusherThree types of hydraulic mills are grouped here: a sawmill from Rafz (Zurich) probably dating from 1841, an 18th-century mill from Graubünden converted into a linseed crusher in 1930 and a bone mill from 1800 coming from Knonau (Zurich). Bone powder, which contains more than 20% phosphates, was added to manure as a natural fertiliser.