VOICE. 



fiftencies, forms, 5:c. of the divers parts of the mouth, 

 contribute to the refonance, each in their way ; and from 

 this mixture of fo many different refonances in their due 

 proportion, there refults a melody in the human voice f jpe- 

 rior and more affefting than it is in the power of the greatefl 

 mufician to equal upon inftruments. Hence it is, that 

 when any of thefe parts are difordered, e. gr. when the nofe 

 is Hopped, the voice becomes difpleafing. 



The refonance in the cavity of the mouth does not feem 

 to confift ill a fimple refleftion, luch as that of a vault, &c. 

 but in a refonance proportionate to the tones of the found 

 fent into the mouth from the glottis ; and, accordingly, 

 we find this cavity to lengthen and (horten itfelf, according 

 to the depth, or acutenefs, of the tone. 



Now, for the trachea to effeft this refonance, as it was 

 the common opinion it did, it would be required, that the 

 air, after its being modified, and turned into found, by the 

 glottis, inftead of continuing its courfe from within out- 

 wards, (hould return from without inwards, and thus ftrike 

 on the fide of the trachea ; which can never happen, except 

 in thofe who have a violent cough, and in ventriloquous per- 

 fons. Indeed, ;n moft river-fowl, which have a very (Irong 

 voice, the trachea does refound ; but the reafon is, that 

 in them the glottis is placed at the bottom of the trachea, and 

 not at the top, as in men. 



The canal, then, which at firft parted for the principal 

 organ of voice, is now found not to be fo much as the fe- 

 condary one, i. e. not that which occafions the refonance. 

 It does not ferve the glottis, as the body of the flute does 

 its plug ; but, inftead of that, the mouth ferves the glottis, 

 as the body of fome other wind-inftrument not yet known 

 in mufic. In effeft, the ofBce of the trachea is no other 

 than that of the port-vent in an organ ; w'x.. to furnifli 

 wind. 



The vowels and femivowels are •ontinuous founds, chiefly 

 formed by this apparatus in the glottis, and modified either 

 in their origin or in their progrefs by the various arrange- 

 ments of the different parts of the mouth. Of fimple 

 vowels, fixteen or eighteen may be enumerated in different 

 languages : in the French nafal vowels, the found is in part 

 tranfmitted through the noftrils, by means of the depreffion 

 of the foft palate : the perfeft femivowels differ from the 

 vowels only in the greater refiftance which the air under- 

 goes in its paffage through the mouth ; there are alfo nafal 

 and feminafal femivowels. The perfeA confonants may be 

 either explofive, fufurrant, or nmte ; the explofive confo- 

 nants begin or end with a found formed in the larynx, the 

 others are either whifpers, or mere noifes, without any vocal 

 found. By attending to the various pofitions of the organ, 

 and by making experiments on the effedls of pipes of dif- 

 ferent forms, it is poffible to conftruft a machine which 

 fliall imitate very accurately many of the founds of the hu- 

 man voice ; and this has indeed been adlually performed by 

 Kratzenftein and by Kempelen. 



A kind of experimental analyfis of the voice may be thus 

 exhibited. By drawing in the breath, and at the fame time 

 properly contrafting the larynx, a flow vibration of the li- 

 gaments of the glottis may be produced, making a diftinft 

 choking found : upon ii'.creafing the tenfion, and the velo- 

 city of the breath, this chcking is loft, and the found be- 

 comes continuous, but of an extremely grave pitch : it may, 

 by a good ear, be diftinguiflied two oftaves below the lowell 

 A of a common bafc voice, confifting in that cafe of about 

 twenty-fix vibrations in a fccond. The fame found may be 

 raifed nearly to the pitch of the common voice ; but it is 

 never fmooth and clear, except perhaps in fome of thofe 

 perfons called ventriloquifts. When the pitch is raifed ftill 



higher, the upper orifice of the larynx, formed by the futn- 

 mits of the aretynoid cartilages and the epiglottis, feems 

 to fuccecd to the office of the hgaments of the glottis, and 

 to produce a retrograde falfetto, which is capable of a Tety 

 great degree of acutenefs. The fame difference probably 

 takes place between the natural voice and the common fal- 

 fetto : the rimula glottidis being too long to admit of a 

 fufficient degree of tenfion for very acute founds, either the 

 upper orifice of the larj-nx fuppHes its place, or fome 

 other fimilar change is produced ; hence, taking a note 

 within the compafs of either voice, it may be held, with 

 the fame expence of air, two or three times as long in a 

 falfetto as in a natural voice ; hence, too, arifes the diffi- 

 culty of paffmg fmoothly from the one voice to the other. 

 It has been remarked, that the larynx is always elevated 

 when the found io acute : but this elevation is only necef- 

 fary in rapid tranfitions, as in a (hake ; and then probably 

 becaufe, by the contraftion of the capacity of the trachea, 

 an increafe of the preffure of the breath can be more 

 rapidly affefted this way, than by the aftion of the abdo- 

 minal mufcles alone. The refieftion of the found, thus 

 produced from the various parts of the cavity of the mouth 

 and noftrils, mixing at various intervals with the portions of 

 the vibrations direftly proceeding from the larynx, muft, 

 according to the temporary form of the parts, varioufly 

 affeft the laws of the motion of the air in each vibration ; 

 or, according to Euler's expreflion, the equation of the 

 curve conceived to correfpond with this motion, and thus 

 produce the various charafters of the vowels and femi- 

 vowels. The principal founding-board feems to be the 

 bony palate : the nofe, except in nafal letters, affords but 

 little refonance ; for the nafal paffage may be clofed, by 

 applying the finger to the foft palate, without much alter- 

 ing the found of vowels not nafal. A good ear may dif- 

 tinftly obferve, efpecially in a loud bafe voice, beCdes the 

 fundamental note, at leaft four harmonic founds, in the 

 order of the natural numbers ; and, the more reedy the tone 

 of the voice, the more eafily they are h-'ard. Faint as they 

 are, their origin is by no means eafy to be expL.ined. This 

 obfervation is precilely confirmed, in a late differtation of 

 M. Knecht, pubhfhed in the mufical newfpaper of Leipfic. 

 Perhaps, by a clofe attention to the harmonics entering into 

 the conftitution of various founds, more may be done in 

 their analyfis than could otherwife be expedled. Young's 

 Philofophy, vols. i. and ii. 



Voice, For the Cauje of the different Tones of. As the 

 organs that form the voice make a kind of wind-inftrument, 

 we might expeft to find in this inftrument fome provifioii 

 anfwerable to that which produces the differences of tones 

 in fome other wind-inftruments. The tone, therefore, muft 

 be attributed either to the mouth and noftrils, which occa- 

 fion the refonance, or to the glottis, which produces the 

 found ; and as all the different tones are produced in man 

 by the fame inftrument, it follows, that the part which pro- 

 duces them, muft be capable of fimilar inftrumental changes. 

 Now, for a grave tone, we know there is more air re- 

 quired than for an acute one. The trachea, therefore, to 

 let this gre.iter quantity pafs, muft dilate and (horten itfelf ; 

 by which (hortening, the external canal, that is, the canal 

 of the mouth and nofe, reckoned from the glottis to the 

 lips, or noftrils, is lengthened. For, the (hortening of the 

 internal canal, t. e. of the trachea, brings the larynx and 

 glottis lower down ; and, of confequence, makes its dif- 

 tance from the mouth, &c. greater ; and there is a change 

 in the length of each canal, for every change of tone and 

 femitone. Accordingly, it is eafy to obferve, that the knot 

 of the larynx alternately rifes and falls in all divifions, 



fhakes, 



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