Hoosac Tunnel East Entrance Stereoview c1870 Construction Massachusetts A2102 For Sale

This is a stereoview (also known as a stereograph or stereoscope card). It was one of the first forms of 3D photography. The images were captured with a special stereoscopic camera, which had two lenses - simulating the view of our left and right eyes. The two, nearly identical pictures were then mounted next to each other (most commonly on a piece of cardstock, glued on as photographs or printed as lithographs). The image could then be seen in three dimensions when viewed through a device known as a stereoscope, stereopticon, televiewer and/or realisticscope.

Standard-size stereograph, measuring about 3.5 x 7 inches.