at. 17, 1878] 



NATURE 



649 



appear as in Fig. 17, with half the number of teeth in Fig. 

 16. because the lower octave of a sound is given by half 

 the number of vibrations. 

 Experiment 20. — Sing the vowel-sound on the note 



and you Avill see Fig. 18 in the mirror. This evidently is 

 not the figure that would have been made by a simple 

 vibration. It shows that this sound is compound, and 

 formed of two simple sounds, one the octave of the other. 

 The larger teeth are made by ever)^ alternate vibration 

 of the higher simple sound acting with a vibration of the 

 lower, and thus making the flame jump higher by their 

 combined action on the membrane. 



Experiment 2\. — Fig. 19 appears on the mirror when 

 we sing the English^owel a on the note f. 



Figs. 16, 17, 18, 19, 20. 



Experiment 22. — Fig. 19 appears on the mirror when 

 we sing the English vowel a on the note c. 



Examine attentively Fig. 19. This shows that the 

 English vowel a sung on f is made up of two combined 

 simple vibrations. One of these alone would make the 

 long tongues of flame, but with this simple vibration 

 exists another of three times its frequency ; that is, the 

 vibration of greater frequency is the 3rd harmonic of 

 the slower. As the slower vibration, making the long 

 tongues of flame, is f, the higher must be ^■'of the second 

 octave above f. Each third vibration of this higher har- 

 monic coincides with each vibration of f; hence each 

 third tongue of flame is higher than the others. 



Experimefit 23. — In like manner the student must 

 analyse Fig. 20 into its simple sonorous elements. Then 

 he should, with the vibrating flame, examine the pecu- 

 liarities_ot the various voices of his friends, and make neat 



and accurate drawings of the flames corresponding to 

 them, so that he may analyse them at his leisure. 



Expetiment 24.— Blow your toy trumpet into the 

 paper cone gently, and then strongly, and observe that 

 the sound given by the trumpet is a complex one. Try if 

 you cannot get a flame somewhat like the trumpet gives 

 by singing ah, through your nose, into the cone. 



The student will soon find that different persons, in 

 singing the same note, as nearly alike as they can, will 

 produce flames of very different forms. This is because 

 the voices differ in the number and relative intensities of 

 the simple sounds which form them. 



Another cause of the different forms of flame obtained 

 by different experimenters is due to the fact that they have 

 used different lengths of tube leading from the cone to the 

 membrane. 



Experiment 25. — The fact can be readily shown by 

 singing the same compound sound through different 

 lengths of tube leading from the cone G to the membrane. 



Terquem^s Experiment, in which Konig's Flame is used 

 instead of the Ear, and thtis the Motions of a Vibrating 

 Disk are made Visible. 



The method of analysing the motions of a vibrating 

 plate with the paper cone and tube applied to the ear, 

 which has been used by us for a long time, has quite re- 

 cently been adapted to M. Konig's flame by Prof. Terquem, 

 of Lille, who has thus made these motions visible to the 

 student, and has given us a charming experiment. 



On how we Speak, and on the Talking Machines of 

 Faber and Edison. — How we Speak. 



The little musical instrument with which we sing and 



speak is formed of two flexible membranes stretched side 



by side across a short tubular box placed on the top of 



the windpipe. This box is made of plates of cartilage, 



A . B 



CVjry 



Fig. 21. 

 Figs, a and b. — Views cf the human larj'nx from above as actually seen, by 

 the aid of the instrument called the larjTigoscope. Fig. a. — In the con- 

 dition when voice is being produced. Fig. B.^At rest, when no voice is 

 produced, e, epiglottis (foreshortened) ; cv, the vocal chords ; cvs, the 

 so-called false vocal chords, folds of mucous membrane lying above the 

 real vocal chords ; a, elevation caused by the arytenoid cartilages; s, w, 

 elevations caused by small cartilages connected with the arytenoids; 

 /, roct of the tongue. 



movable on each other, and bound together with muscles 

 and membranes. 



The top of the windpipe is fonned of a large ring of 

 cartilage, called the cricoid (ring-shaped) cartilage. 

 Jointed to this is a broad plate of gristle, called the 

 thyroid (shield-shaped) cartilage. This cartilage is bent 

 into the shape of a V- The legs of this V straddle over 

 the cricoid and are jointed to its outer sides. The peak 

 of the V stands up and points toward the front of your 

 throat. You can feel it, as it is the "Adam's apple." 

 On the back of the upper edge of the cricoid ring are 

 jointed two small pointed cartilages, known as the 

 arytenoid (funnel-shaped) cartilages. Stretching from 

 these to the inner sides of the legs of the V of the 

 thyroid are two membranes, one to each leg. These are 

 the vocal chords. 



"When the point of the thyroid is not pulled down 

 these membranes are lax, and the breath from the wind- 

 pipe passes freely between them and does not make them 

 vibrate. {See B of Fig. 21.) 



But when the peak of the thyroid is pulled down by 



