STAGE FLOOR INSIDE
On this floor one finds an old grain purifier and baking breaker, which are actually no longer in service.
The meal which has been milled one floor above, gets directed into one of the grain warehouses for storage.
This happens via the "Meal Spout". 
The two coupled stones which are wind-driven, also have their regulators installed here.
This is a mechanism with 2 red balls that turn according to the speed of the turning milling stones.
The faster that the stones turn, the greater becomes the resistance between them.
In this way the amount of darting material can be reduced (by inconsistent wind conditions).