550 



EXPERIMENTS AND INQUIRIES 



originally proposed to be illustrated by these 

 researches, is of so complicated a nature, and 

 so imperfectly understood, that it can be on 

 this occasion but superficially considered. 

 No person, unless we except M. Ferrein, has 

 published any thing very important on the 

 subject of the formation of the voice, before 

 or since Dodart; his reasoning has fully 

 shown the analogy between the voice and the 

 vox humana and regal organ pipes ; but his 

 comparison with the whistle is unfortunate : 

 nor is he more happy in his account of the 

 falsetto. A kind of experimental analysis of 

 the voice may be thus exhibited. By draw- 

 ing in the breath, and at the same time pro- 

 perly contracting the larynx, a slow vibra- 

 tion of the ligaments of the glottis may be 

 produced, making a distinct clicking sound : 

 upon increasing the tension, and the velocity 

 of the breath, this clicking is lost, and the 

 sound becomes continuous, but of an ex- 

 tremely grave pitch : it may, by a good ear, 

 be distinguished two octaves below the lowest 

 A of a common bass voice, consisting in 

 that case of about 26 vibrations in a second. 

 The same sound may be raised nearly to the 

 pitch of the common voice ; but it is never 

 smooth and clear, except perhaps in some 

 of those persons called ventriloquists. When 

 the pitch is raised still higher, the upper ori- 

 fice of the larynx, formed by the summits of 

 the arytaenoid cartilages and the epiglottis, 

 seems to succeed to the ofiice of the liga- 

 ments of the glottis, and to produce a retro- 

 grade falsetto, which is capable of a very 

 great degree of acuteness. Tlie same differ- 

 ence probably takes place between the natu- 

 ral voice and the common falsetto : the rimula 

 glottidis being too long to admit of a suffici- 

 ent degree of tension for very acute sounds, 

 either the upper orifice of the larynx supplies 



4 



its place, or, some other similar change is 

 produced ; hence, taking a note within the 

 compass of either voice, it may be held, with 

 the same expense of air, two or three times 

 as long in a falsetto as in a natural voice 5 

 hence, too, arises the difficulty of passing 

 smoothly from the one voice to the other. It 

 has been remarked, that the larynx is alvvay9 

 elevated when the sound is acute: but this 

 elevation is only necessary in rapid transi- 

 tions, as in a shake ; and then probably be- 

 cause, by the contraction of the capacity of 

 the trachea, an increase of the pressure of 

 the breath can be more rapidly affected this 

 way, than by the action of the abdominal 

 muscles alone. The reflection of the sounds 

 thus produced from the various parts of the 

 cavity of the mouth and nostrils, mixing at 

 various intervals with the portions of the vi- 

 brations directly proceeding from the larynx, 

 must, according to the temporary form of 

 the parts, variously affect the laws of the 

 motion of the air in each vibration ; or, 

 according to Euler's expression, the equa- 

 tion of the curve conceived - to corre- 

 spond with this motion, and thus produce 

 the various characters of the vowels and se- 

 mivowels. The principal sounding board 

 seems to be the bony palate : the nose, ex- 

 cept in nasal letters, affords but little reso- 

 nance ; for the nasal passage may be closed, 

 by applying the finger to tiie soft palate, 

 without much altering the sound of vowels 

 not nasal. A good ear may distinctly ob- 

 serve, especially in a loud bass voice, be- 

 sides the fundamental note, at least four 

 harmonic sounds, in the order of the natural 

 numbers ; ^ and, the more reedy the tone of 

 the voice, the more easily they are heard. 

 Faint as they are, their origin is bv no means 

 easy to be explained. This observation is 



