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NATURE 



\_Oct. 17, i8;8 



its muscles the vocal chords are stretched. At the same 

 time the arytenoid cartilages move nearer each other, and 

 the thin, sharply-cut edges of the vocal chords are brought 

 parallel and quite close to each other, as is shown in A of 

 Fig. 21. If the air is now forced through this narrow 

 slit (called the glottis), the vocal chords vibrate just like 

 the tongue in our toy trumpet, or like the reed in any 

 reed-pipe. A puff of air passes between them ; they sepa- 

 rate; immediately afterward they come close together 

 and the current of air is stopped. They again open, 

 another puff goes into the cavity of the mouth, and then 

 they close together again. Thus the glottis opens and 

 closes with a frequency depending on the degree of 

 stretch on the vocal chords. 



Our experiments with Konig's flame have shown how 

 composite are the sounds of the human voice. The quality 

 of a voice depends on the number and relative intensities 

 of the simple sounds which build it up. 



Speech is voice modified and modulated by the move- 

 ments of the parts of the cavity of the mouth, of the 

 tongue, and lips. 



The oral cavity is made larger or smaller, longer or 

 shorter, and thus, resounding to some lower or higher 

 harmonic of the voice, makes the others feebly heard. 



Experifnetit 26. — If you form your speaking organs to 

 say 0, and then take your vibrating A-fork and hold it 

 before your lips, you will hear the cavity of the mouth 

 resounding to this sound. On changing the vocal organs 

 to say e the resonance ceases. 



All the vowel sounds are formed by a steady voice 

 modified by the resonance of the different sizes and 

 shapes given to the oral cavity. 



The consonants are made by obstructions placed at the 

 beginning or end of the oral sounds, by the movements of 

 the tongue and lips ; but, as this is a book of experi- 

 ments, I leave you to inform yourself by experiments as 

 to these matters. 



Experiments in which a Toy Trufnpet Talks ana a 

 Speaking Machi?ie is Made. 



Experiment 27. — Sing ah, and while doing so quickly 

 open and shut your lips twice. These two sudden 

 obstructions to the sound have made you say tnama. 

 If you will observe attentively the motion of your mouth 

 you will see that for the last syllable of mama you open 

 your mouth wider and keep it open longer than for the 

 first syllable. 



Experiment 28. — This is all we have to know to make 

 our toy trumpet talk. You already have seen that its sounds. 



Fig. 22. 



like those of the human voice, are made by puffs of air. 

 These pass the reed every time it goes above or below 

 the oblong hole in the plate in which it vibrates. Your 

 experiments with Konig's flame have told you that the 

 sounds of the voice are similar— that both are highly 

 composite. 



Let, then, the vibrating reed in the trumpet stand for 



your vocal chords. To get a resonant cavity like tie 

 mouth make one between your two hands, as shown in A 

 of Fig. 22. The funnel of the trumpet is placed inside 

 this cavity with the tube coming out in the crotch between 

 the thumb and forefinger. The lips we will form of the 

 fingers of one hand. By raising these together, more or 

 less, from the other hand we can make a larger or smaller 

 opening into the cavity between the palms of the hands, 

 and thus get articulation. 



Now blow into the trumpet as though you were speaking 

 mama into it, so that you may make it sound twice, each 

 sound lasting just as long as the sounds in ma and ma. 

 While making the first sound, raise the fingers as high as 

 is shown in A ; while making the second, raise them as 

 high as is shown in B. The trumpet talks and says mama 

 quite plainly. 



Experiment 28. — Let us make a talking machine. 

 Get an orange with a thick skin and cut it in halves. 

 With a sharp dinner-knife cut and scrape out its soft 

 inside. You have thus made two hemispherical cups. 

 Cut a small semicircle out of the edge of each cup. 

 Place these over each other, and you have a hole for the 

 tube of the trumpet to go out of the orange. Now sew 

 the two cups together, except a length directly opposite 

 the trumpet, for here are the lips. A pea-nut makes a 

 good enough nose for a baby, and black beans make 

 "perfectly lovely" eyes. Take the baby's cap and place 

 it on the orange, and try if you can make it say 



Fig. 23. 



Fader's Talking Machine. 



These simple experiments show the principles followed 

 in the construction of the celebrated talking machine of 

 Faber of Vienna. A vibrating ivory reed, of variable 

 pitch, forms its vocal chords. There is an oral cavity 

 whose size and shape can be rapidly changed by de- 

 pressing the keys on a key-board. Rubber, tongue, and 

 lips make the consonants. A little windmill turning in 

 its throat rolls the r, and a tube is attached to its nose 

 when it speaks French. This is the anatomy of this 

 really wonderful piece of mechanism. 



ELECTRIC LIGHTING 



A LL the papers are still much occupied with corre- 

 ■^ *- spondence about the electric light, the extent to 

 which it may be brought into public use, and its possible 

 effect upon the use of gas and upon gas companies. Many 

 writers display much ignorance both as to the scientific 

 and economical bearings of the matter ; the most im- 

 portant communication on the subject that has appeared 

 is the letter from Dr. C. W. Siemens in the Times of the 

 1 2th inst. Dr. Siemens writes as follows : — 



The intelligence flashed through the Atlantic cable a few days 

 since to the effect that Mr. Edison, the ingenious inventor of the 

 phonograph, &c., had succeeded in dividing electric currents 



