Professor Hasner's automatic eyeball, 1862

Professor Hasner's automatic eyeball, 1862. '...mechanical model of the eye,...made chiefly for the purpose of demonstrating the complicated and beautifully-contrived muscular movements of the human eyeball...[formed of] a hollow sphere of brass acting on a ball-and-socket joint...A set of strings being secured at proper intervals around the eyeball, each one of which is inserted with anatomical correctness, represent the several muscles of the human eye, and pass at a given distance to a set of small rollers, seen in the Engraving...Each of the rollers has a small pointer, which moves when the string is set in motion over the face of the semicircular plate seen standing near. Each thread then descends to the interior of the box, and is there made fast to as many levers or keys...The keys...when touched, indicate the name of the muscle put in motion, at the same instant its angular movement and deviation are accurately recorded and measured...the pointer shows with mathematical accuracy the limits of [the eyeball's] movements, as well as the power exerted, as one after the other are made to move the globe upwards, downwards, inwards, or outwards. The inventor has generously presented the instrument to the London Ophthalmic Hospital'. From "Illustrated London News", 1862. Creator: Unknown. (Photo by The Print Collector/Heritage Images via Getty Images)