460 OF THE VOICE AND SPEECH. 



human voice, may be made by increased tension to produce all the superior notes, which, 

 in stringed instruments, are ordinarily obtained by shortening the strings.* But it does not 

 follow that a short string, which, with moderate tension, naturally produces a high note, 

 should be able, by a diminution of the tension, to give out a deep one; for, although this 

 might be theoretically possible, yet it cannot be accomplished in practice; since the vibrations 

 become irregular on account of the diminished elasticity ."f" These considerations are in them- 

 selves sufficient to destroy the supposed analogy ; and to prove that the Chorda? Vocales can- 

 not be reduced to the same category with vibrating strings. 



b. The next kind of instrument, with which some analogy ijpight be suspected, is the 

 Flute-pipe, in which the sound is produced by the vibration of an elastic column of air con- 

 tained in the tube ; and the pitch of the note is determined almost entirely by the length of the 

 column, although slightly modified by its diameter, and by the nature of the embouchure or 

 mouth from which it issues. This is exemplified in the German Flute, and in the English 

 Flute or Flageolet; in both of which instruments, the acting length of the pipe is determined, 

 by the interval between the embouchure and the nearest of the side apertures; by opening 

 or closing which, therefore, a modification of the tone is produced. In the Organ, of which 

 the greater number of pipes are constructed upon this plan, there is a distinct pipe for every 

 note: and their length increases in a regular scale. It is, in fact, with flute-pipes as with 

 strings, that a diminution in length causes an increase in the number of vibrations, in an 

 inverse proportion ; so that of two pipes, one being half the length of the other, the shorter 

 will give a tone which is the octave above the other, the vibrations of its column of air being 

 twice as rapid. Now there is nothing in the form or dimensions of the column of air be- 

 tween the larynx and the mouth, which can be conceived to render it at all capable of such 

 vibrations, as are required to produce the tones of the Human voice; though there is some 

 doubt, whether it is not the agent in the musical tones of certain Birds. The length of an 

 open pipe necessary to give the lowest G of the ordinary bass voice, is nearly six feet ; and 

 the conditions necessary to produce the higher notes from it, are by no means those which 

 we find to exist in the process of modulating the human voice. 



c. We now come to the third class of instruments, in which sound is produced by the 

 vibration of Reeds orTongues; these may either possess elasticity in themselves, or be made 

 elastic by tension. The reeds of the Mouth- EoLina, Accordion, Seraphine, &c., are examples 

 of instruments of this character, in which the lamina vibrates freely in a sort of frame, that 

 allows the air to pass out on all sides of it through a narrow channel, thus increasing the 

 strength of the blast: whilst in the Hautboy, Bassoon, &c., and in Organ-pipes of similar con- 

 struction, the reed is attached to one end of a pipe. In the former kind, the sound is pro- 

 duced by the vibration of the tongue alone, and is regulated entirely by its length and elasti- 

 city; whilst in the latter, its pitch is dependent upon this conjointly with the length of the 

 tube, the column of air contained in which is thrown into simultaneous vibration. Some 

 interesting researches on the effect produced on the pitch of a sound given by a reed, through 

 the union of it with a tube, have been made by M. W. Weber ; and, as they are important 

 in furnishing data, by which the real nature of the vocal organ may be determined, their 

 chief results will be here given. i. The pitch of a reed may be lowered, but cannot be 

 raised, by joining it to a tube. u. The sinking of the pitch of the reed thus produced, is at 

 the utmost not more than an octave, in. The fundamental note of the reed thus lowered, may 

 be raised again to its original pitch, by a further lengthening of the tube; and by a further 

 increase is again lowered, iv. The length of tube, necessary to lower the pitch of the in- 

 strument to any given point, depends on the relation which exists between the frequency of 

 the vibrations of the tongue of the reed, anil those of the column of air in the tube, each 

 taken separately. From these data, and from those of the preceding paragraph, it follows 

 that, if a wind-instrument can, by the prolongation of its tube, be made to yield tones of any 

 depth in proportion to the length of the tube, it must be regarded as a Bute-pipe; whilst, if 

 its pitch can only be lowered an octave or less (the emlxiiiehuiv remaining the <amc) by 

 lengthening the tube, we may be certain that it is a reed instrument. The latter proves to 

 be the case in regard to the Larynx. 



607. It is evident from the foregoing considerations, that the action of the 

 Larynx has more analogy to that of reed instruments, than it has to that either 



* Thus in the Piano-forte, where there are strings tin- each note, a gradual shortening is 

 seen from the lowest to the highest; and in the \ lolin the change of tone is produced by 

 slopping the strings with the linger, so as to diminish their acting length. 



f Thus it would be impossible to produce good Bass notes on the strings of a Violin, by 

 diminishing their tension; the len-ih allorded l>y the Violoncello or Double Bass is requisite. 

 The striking dill'ereiiee between the tone of the Bass strings in the Grand Piano-forte and the 

 small upright Piccolo, is another e\eiiii>lilieaiii>n of the same principle; being chiefly due to 

 the length and tension of the former, as contrasted with the shortness and slackness of the 

 latter. 



