Hierarchy classification:

1. top of the aat hierarchies
2. Objects Facet
3. Furnishings and Equipment (hierarchy name)
4. Measuring Devices (hierarchy name)
5. measuring devices (instruments)
6. [measuring devices for forces]
7. movement measuring devices
8. object movement measuring devices

Anotations

Scope note:

Instruments designed to demonstrate the mothion of rotating bodies, consisting essentially of a rotating wheel mounted in a ring, with its axis free to turn in any direction. With modifications or in conjunction with other equipment, these may be used as navigational devices, or to stabilize ships and mono-rail vehicles.