The Vérascope revolving stereoscope is based on a patent by Alexander Beckers from New York. It was therefore also called Beckers style or American style stereoscope. The design is based on a construction with a chain that contains holders for the stereoviews. By rotating the chain, the stereoviews can be viewed one by one.
This type of stereo viewer does not offer the best viewing experience and replacing the stereoviews is cumbersome. However, these viewers remained popular, even after more sophisticated slide tray stereoscopes, such as the Taxiphote, were introduced.
The revolving stereoscope had some advantages. They were cheaper and many models support both paper card stereoviews and glass stereoviews. This Vérascope revolving stereoscope is made for the 45x107mm glass format only and has no mirror to illuminate paper cards. The chain is made of iron to carry the heavier glass slides. It is attached to the device and can’t be removed, which would make replacing the slides easier. This model can carry 50 slides but there were also tall floor-models for 100 and 200 slides. The achromatic lenses can be focussed but the distance between both lenses can’t be adjusted. A frosted glass at the back illuminates the glass slides.
Jules Richard introduced later the Kalloscope, which was a more sophisticated revolving stereoscope. It was based on a patent of Richard and Chauvelon. The Kalloscope moves the entire chain down before it rotates to the next image. Because the actual rotating is not visible in front of the lenses, the viewing experience is enhanced.
- Wing, Paul. Stereoscopes: the first one hundred years, 1996
- Catalog Jules Richard, 1913
- Catalog Jules Richard, 1926