227. Collection of metal stands and rods, etc.
or:
228. Holder for prisms. By Kohl, Chemnitz. $3.
or:
229. Universal holder. By Cambr. Scient. Instr. Co. $10.
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))
