Description:
Large heavy-weight cardboard disk with 24 concentric circles of holes punched in a star-like pattern. On the reverse, the circles are marked in ink with (a) the number of holes that would pass in front of a jet of air in each circle as the disk was rapidly rotated to produce a particular note; (b) musical intervals produced; and (c) chords produced.
Back has handwritten inscription: "Rapports des nombres de trous, 2, 3, 4, 5, 6, 8, 10, 12, 16, 20, 24, 32, 40, 45, 54, 5/4, 4/3, 3/2, 5/3, 7/4, 6543, 8654, 6543, 8654."
Translation: "Numbers correspond to the number of holes."