Sir Charles Wheatstone, was an English scientist and inventor of many scientific breakthroughs of the Victorian era, including the English concertina, the stereoscope, and the Playfair cipher. However, Wheatstone is best known for his contributions in the development of the Wheatstone bridge, originally invented by Samuel Hunter Christie, which is used to measure an unknown electrical resistance, and as a major figure in the development of telegraphy.

A stereoscope is a device for viewing a stereoscopic pair of separate images, depicting left-eye and right-eye views of the same scene, as a single three-dimensional image.