by John M. Schoenknecht

With the introduction of the stereoscope in the early 19th century, a new world was revealed. A stereoscope uses two nearly-identical images, each taken a few inches to the side of each other. The image is then viewed through two lenses set approximately 2.5 inches apart. The result is the illusion of a three-dimensional photograph.

The earliest stereoscopes used drawings, since photography had not been invented. According to the website, “by the 1850s, photography was possible so stereoscopes began featuring this new technology.”

242 pages, black & white photos.