Handbook of the practice and art of photography (1875)
Vogel, Hermann Wilhelm, 1834-1898, Molling, Edward F · Philadelphia, Benerman & Wilson · leaf 271
removed from one another the right and left view differ very little, and the distances do not appear very solid. In Germany we use the German and English boxes for this work. A very practical camera for stereoscopic work is the one called the " Philadelphia Box," made by the American Optical… … rapidly raised and depressed by turning a knob. The exposure can, of course, be lengthened at pleasure. The whole arrangement fits only loosely on the objective,
Photography
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.
