The book stereoscope was designed by Smith, Beck & Beck. The company was founded by James Smith. He started a partnership with his former apprentice Richard Beck in 1847. Richard's brother Joseph also joined the company and from 1857 it's known as Smith, Beck & Beck.
The company was primarily an optical instrument maker and specialised in microscopes. It manufactured also stereoscopes and was a publisher of stereocards and glass stereoviews. Their attention to stereoscopy products was most likely prompted by the great popularity of stereoscopy in the 1850s. James Smith retired in 1865 and the company continued as R & J Beck.
The book stereoscope is based on Joseph Beck's patent of 1859. It's designed for viewing stereocards and stereoscopic images that are mounted in a book. The stereoscope was very successful and around 3000 devices were produced until c.1890. As far as I know this is the most complete book stereoscope ever produced.
The two prismatic achromatic lenses can be focussed and may be rotated to adjust for stereoscopic images of various sizes. The left lens of my viewer has the inscription R & J Beck, which indicates that it's manufactured between 1865 and 1890. A septum between the lenses consists of a frosted glass and the baseplate has a mirror to reflect light.
The end of the viewer has two small clamps that can be used to mount a stereocard. The clamps can be turned away when the viewer is used to rest directly upon a stereoscopic image that's mounted in a book. The bottom contains a handgrip with the text Patent Mirror 2026.
David Starkman has written an excellent article on the history of books with stereoscopic images and book stereoscopes: An Abbreviated History of Stereo-Pair Illustrated books.
- An Abbreviated History of Stereo-Pair Illustrated books
- Encyclopedia of nineteenth-century photography, J. Hannavy, 2008
- Stereoscopes, the first one hundred years, P. Wing, 1996