Unlike the lustrous shades of chocolate colored pearls, natural brown pearls are a warm black-brown color and sometimes have a very slight coppery colored overtone.
Try to determine the overtone of the pearls.
The first overtone of the second will beat 64 times per second with the third of the first, and at such height in the scale this frequency will be unpleasant.
Thus, suppose a fundamental 256 has present with it overtone harmonics 512, 768, 1024, 1280, &c., and that we sound with it the major seventh with fundamental 480, and having harmonics 960, 1440, &c. The two sets may be arranged thus c 256 512 768 1024 1280 h 480 960 1440, and we see that the fundamental of the second will beat 32 times per second with the first overtone of the first, giving dissonance.
If it is touched in the middle with a feather, the edge of a card, or the finger nail, and bowed a quarter of the way along the octave, the first overtone comes out.
Thus if a fork Ut 3 = 256 is used, the length of pipe for the fundamental at o° C. is about 33,000/4X256 =33 cms. If a fork Solo= 768 is used the pipe resounds to it according to the mode of the first overtone.
The first overtone has frequency 6.25 that of the fundamental, and is not in the harmonic series.
If, however, the pipe is blown strongly, the funda mental dies away, and the first overtone is predominant.