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THE POPULAR SCIENCE MONTHLY. 



ing the resounding column of air, from the water to the top of the jar, 

 we find it to be 7i inches, one-fourth the length of the A-wave. Now, 

 by making a resounder of this size, with an ear-opening in the bottom, 

 we shall have an instrument that will pick out A every time from a sea 

 of sound. This resonator is shown in Fig. 9 ; and Fig. 10 shows an- 

 other form of the same instrument. Resonators tuned to the different 



Fig. 9. 



notes are made, and by their aid any sound can be analyzed, and each 

 overtone brought out like the throbbing of a single string. 



In this way it has been found that the peculiar character, or stamp, 

 of any sound depends on its overtones, and furthermore on exactly 

 what ones, so that by reproducing them any sound can be imitated. 

 Of all sounds those of the human voice are the sweetest. None others 

 are so rich in harmonic overtones, and this brings us to Words. 



The vocal mechanism is made in two pieces. One, a wonderful 

 musical instrument with only one vibrator the vocal chords, Fig. 11 

 which can tune itself at once to any note. The other, the mouth, as 

 an echo-cave or resonator, no less wonderful in its power of forming 

 itself to resound the harmonics of the vocal tones. This gives the 



Fig 10. 



Fig. 11. 



voice its power of imitating any sound within its reach. We will 

 analyze the voice. 



Let the vocal chords sing or vibrate any note, and by merely chang- 

 ing the hollow of the mouth the purely musical sound will turn into 

 what are called the vowe^-sounds of speech, the closest position of the 

 mouth making it ee, the deepest oo. Why is this, since the musical 

 note is the same in each ? It is because the different positions of the 

 mouth resound to different overtones. While some vowel is sung we 



