Einstein and Wertheimer | Street Peek-A-Boo

D. Brett King and Michael Wertheimer, Max Wertheimer and Gestalt Theory. New Brunswick NJ: Transaction Publishers, 2005, p. 122—

He [Albert Einstein] seemed also to relish his intellectual and social exchanges with [his friend, Gestalt psychologist Max] Wertheimer. Wertheimer was once amused when he and Einstein consecutively covered their right and left eyes with their hands to test the effects of retinal disparity (the slightly different images of the same object on the two retinas because of the spatial separation of the eyes) as they stared at a church steeple.  Watching these figures on the street corner, a crowd soon gathered and the two were surprised to see that the onlookers were also engaging in this curious behavior, shifting their hands back and forth over their eyes. more>>>

Étienne-Jules Marey's 3-D Motion Picture

Without hesitation, one of my favorite people from the past was a 19th-century French scientist named Étienne Jules-Marey (1830-1904). The number and complexity of the things that he invented are almost beyond belief. He began to study animal movement in the late 1860s, then used photography and a photographic gun to record successive stages in the movements of a wide range of animals and of humans. By far, my favorite invention of his (shown here) was very likely the first 3-D motion picture device. Using a spinning drum-like motion picture toy called a zoetrope, he arranged inside of it (on upright wires) a series of tiny wax sculptures of ten stages in the flight of a seagull. By spinning the drum, while bending down and looking through the slits in its side, one could see the breathtaking illusion of a tiny three-dimensional bird, flying through the air. I wonder if this still exists, or if it could be rebuilt. More>>>