This is based on the acoustic device, named after French physicist Félix Savart, and produced by William Ladd in 1870, and is used to create sounds with known frequencies. The device is used to determine the frequency of an unknown pitch. The 'Savart's Tone Wheel' consists of 4 metal discs about 73mmD, mounted on a central shaft so that the set of 4 can be rotated. Each disc has a different number of teeth cut into it so that when a stiff card is placed against the edge of a wheel, a tone is produced.
The teeth are 36, 45, 54 and 72 and this is a ratio of 4, 5, 6, and 8. The combined sound of all 4 discs touching the stiff card is a natural musical chord.

See Instruction Sheet