Early mills used water power. It was at textile mills where water power first reached a high stage of development. Textile mills must have constant speed. Irregular speed means irregular weave.
The Lombard is a remarkably advanced design. It is a sophisticated servo mechanism doing mechanically what today is easy to do electronically. It is belt driven from the turbine it controls. Two counter rotating clutches engage as necessary to raise or lower the turbine’s water flow. The heart of the Lombard is an advanced feedback system using a disk integrator for anti-hunting. Vannevar Bush of MIT used disk integrators in the first, true analog computer in 1929.