What is an instrument with two lenses, by which an image of a single picture projected upon a screen of ground glass is made to present an appearance of relief, and may be viewed by several persons at once called?

stereomonoscope — An instrument with two lenses, by which an image of a single picture projected upon a screen of ground glass is made to present an appearance of relief, and may be viewed by several persons at once. (Webster's 1913.)

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