Two smaller mounted prisms. By Duboscq, Paris. $15.[acc. to No. 94 in Münsterberg, 1893, Psychological Laboratory at Harvard University.]
Source
Anonymous. 1892. Harvard Psychological Laboratory in Dane Hall: Interior of a Laboratory Room (Students studying the effect of attention on color perception). Photograph. (Harvard University Archives - HUPSF Psychological Laboratories (2))
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."
