Charles Weatstone

"The projection of two obviously dissimilar pictures on the two retinae when a single object is viewed, while the optic axes converge, must therefore be regarded as a new fact in the theory of vision. It being thus established that the mind perceives an object of three dimensions by means of the two dissimilar pictures projected by it on the two retinae, the following question occurs: What would be the visual effect of simultaneously presenting to each eye, instead of the object itself, its projection on a plane surface as it appears to that eye?”

J. Wade, Nicholas. "Charles Wheatstone (1802 - 1875)". Great Britain: Pion Publisher, 2002.

In 1830, the English physicist Charles Weatstone discovered that binuclear perception of depth is created in the brain by superimposing two identical images positioned side by side. His first table-top stereoscopic viewing device, constructed by the optician R. Murray in 1932, consisted of two mirrors reflecting two images positioned on either side. This construction entitled "Weatstone's mirror stereoscope" is the precursor of the hand-held or head-mounted stereoscope by David Brewster, and was presented in 1938 to the Royal College of London.