Signedon wooden base: C. H. STOELTING CO. / CHICAGO, ILL.
FunctionThis instrument was designed to measure the intensity of the sound produced as a function of the angular distance transversed by the hard-rubber ball. In this case, with two pendulums, it was used for the purpose of comparison. It enabled a subject to produce a sound of equal (or different) intensity immediately after the fall of the first pendulum.
ProvenancePsychology Department, William James Hall, Harvard University.