Distances. On circle No. 1 24 holes, distances 15° " " 2 24 " " 15° & 27 holes, 13-1/3° " " 3 24 " " 15° " 30 " 12° " " 4 24 " " 15° " 32 " 11-1/4° " " 5 24 " " 15° " 36 " 10° " " 6 24 " " 15° " 40 " 9° " " 7 24 " " 15° " 45 " 8° " " 8 24 " " 15° " 30, 36, & 48 holes Circle 1 produces a single note, circle 2 a second, circle 3 a third, circle 4 a fourth, 5 a fifth, 6 a sixth, 7 a seventh, and 8 a perfect chord. II. _Experiments to prove that the shocks may proceed from two or several different places to conspire in the formation of a note, provided that the isochronism of the shocks is sufficiently exact, and that the shocks are produced in the same direction_. Disk No. 4 has-- On circle 1 24 holes. " " 2 36 " " " 3 23 " " " 4 12 at an angular distance of 10° from the holes of circle 3. " " 5 12 holes at an ang. dist. of 20° from those of circle 3 " " 6 12 " " " 0° " " " 7 12 " " " 15° " " " 8 12 " " " 15° " 1. If from the same side two currents of air at an angular distance of 15° are directed against circle No. 8 of 12 holes, we obtain the octave of the note produced by the same circle if only one current is used. The wind-chest is provided with a special arrangement for this experiment. By pulling out button 8, we give vent to 12 currents of air spaced like the twelve holes of the disk; on pulling out button 9 we also produce 12 currents, but they are situated just between the first. Each of these two buttons pulled out alone will produce the same note corresponding to 12 holes, but drawn together they produce the octave, or the note of circle 1. 2. If two currents of air are directed against two similar circles whose holes are situated on the same radii, we obtain the same result. In this experiment, circles 7 and 8 are sounded by pulling out buttons 7 and 9. 3. When two currents of air are directed on the same radius against two circles of similar holes arranged alternately, these circles sounded simultaneously will produce the octave of the note which one of them would give alone. This experiment is performed by sounding circles 6 and 7 and pulling out buttons 6 and 7. 4. If we direct three currents of air on the same radius against three similar circles having holes alternating by a third of the distance between two holes of the same circle, the three circles together produce the fifth of the octave (Note 3) of a single circle. Circles 3, 4, and 5 sounded together emit the note of circle 2.