Hierarchy classification:

1. top of the aat hierarchies
2. Objects Facet
3. Furnishings and Equipment (hierarchy name)
4. Sound Devices (hierarchy name)
5. sound devices (equipment)

Anotations

Scope note:

Instruments designed to demonstrate visibly the harmonic overtones of all musical notes, by means of a device utilizing gas jet flames and revolving mirrors. This device was presented at the Paris Universal Exhibition of 1867 by Rudolph Koenig.