Three-Eyed Vision

Science cannot give you or me a third eye, but it can give us the magic power to see an object as it would appear to a three- eyed creature. Let me note first that a one- eyed man can get from stereoscopic photographs that impression of relief, which he cannot and does not get in ordinary life. For this purpose, we must project onto a screen in rapid sequence the photographs intended for right and left eyes that a normal person see with both eyes simultaneously. The net result is the same because a rapid sequence of visual images fuses into one image just as two images seen simultaneously do. (It is quite likely that the surprising “depth” of movie films at times, in addition to the causes mentioned, is due also to this. If the movie camera sways with an even motion, as often happens because of the film- winder, the stills will not be identical and, as they rapidly flit onto the screen, they will appear to us as one three- dimensional image). In that case, a two- eyed person simultaneously watches a rapid sequence of two photographs with one eye and a third photograph, taken from another angle. One eye would get a single image, but in relief, from a rapidly alternating stereoscopic pair, while the other eye would look at the third photograph. This “three - eyed” vision enhances the relief to the extreme.