Robert Krawczyk
Crova's Disc Vortex
André Prosper Crova was a faculty member at the University of Montpelier. He invented an acoustic wave model in the 1860s and commissioned the prominent Parisian acoustic instrument maker Rudolph Koenig to manufacture it for him. It was first shown at the 1867 Paris World Fair.
An algorithm was developed that simulates Crova’s Disc with one-to-three revolutions, both circular and elliptical shape. These particular images take the disc one step further to create an imagery vortex by overlaying a three revolution disc on itself. The individual waves are represented by a continuous series of dots.
Three revolution circular Crova’s Disc overlaid and mirrored around horizontal axis.
Crova’s disk was widely used and was manufactured well into the 20th century. His original apparatus included eight separate disks that could show “propagation of a wave pulse, reflection of a wave pulse, propagation of a sound wave, reflection of continuous vibratory movement, fundamental tone of sound pipes, first harmonic of sound pipes, vibrations of ether and interference of two vibratory movements.” Over time, a variety of additional disks were designed which extended its range even further. In 1889 a complete set of eight disks together with a viewing stand cost $80.