Large Scioptric Ball

Large turned mahogany Scioptric Ball or "Ox-Eye". The ball approx. 10cm in diameter mounted in a collar approx. 19cm in diameter. Focal length approx.135cm. This was an improvement of the camera obscura lens. Mounted in the side of a darkened room or tent the lens could be moved around in its socket to project an upside-down and reversed image on the opposite wall. An unusually large and rare example of pre-photography. Illustrated in: "The History of Photography as seen through the Spira Collection", page 11