Anonymous. 1892. Harvard Psychological Laboratory in Dane Hall: Instruments for Experiments on Sight. Photograph. (Harvard University Archives - HUPSF Psychological Laboratories (7))
See a figure of the same prism on another photograph from the Harvard Collection. See a figure in a catalog by Duboscq, 1885. See a color photograph of this device in the Harvard Collection of Historical Scientific Instruments. See another color photograph of a similar prism from Thomas B. Greenslade's collection "Instruments for Natural Philosophy."
