"This unique piece of apparatus uses Lissajous figures to show that the ratio of the frequency ratios in a diatonic scale are ratios of small numbers. On the side is an air-driven vibrating reed with a small mirror attached to its free end....
Crova's apparatus was designed for the purpose of representing vibratory movements on the screen, with 8 disks. Turning the crank past a vertical slit caused the disks to rotate, while a beam of light from the optical system impinged on the slit...
Scientific apparatus and instruments; Santa Clara University (Calif.)
""This unique piece of apparatus uses Lissajous figures to show that the ratio of the frequency ratios in a diatonic scale are ratios of small numbers. On the side is an air-driven vibrating reed with a small mirror attached to its free...