A new modification of the Seashore tonoscope has been developed, similar to the phonograph form already described, using the phonograph motor as a source of power but having a new scale which covers a whole octave, in steps of tenths of a tone. The instrument may be read in terms of twentieths of a tone. These units were chosen because they are close to the sensory limits for interval discrimination and because such units are comparable from one octave to another.
Proceedings of the Iowa Academy of Science
©1928 Iowa Academy of Science, Inc.
Williams, H. M.
"New Developments in the Tonoscope: Measurements on Correct Intonation in Singing,"
Proceedings of the Iowa Academy of Science, 35(1), 300-301.
Available at: https://scholarworks.uni.edu/pias/vol35/iss1/70