Hierarchy classification:

1. top of the aat hierarchies
2. Objects Facet
3. Furnishings and Equipment (hierarchy name)
4. Tools and Equipment (hierarchy name)
5. equipment
6. [equipment by process]
7. image-making equipment
8. photographic equipment
9. photograph viewing equipment

Anotations

Scope note:

Optical devices invented by Carlo Ponti in 1860, and patented in 1861. These were used to view photographic transparencies or prints. It was claimed that stereoscopic relief was obtained from a single photograph, though the stereo effect was due to the nature of an illusion caused by the single viewing lens of the alethoscope.