REGULATION OF THE PITCH OF VOCAL SOUNDS. 557 



and others, that the action of the Vocal ligaments, in the production of 

 sound, bears no resemblance to that of vibrating strings ; and^that it is 

 not comparable to that of the mouth-piece of the flute-pipes of the Or- 

 gan ; but that it is, in all essential particulars, the same with that of 

 the reeds of the Hautboy or Clarionet, or the tongues of the Accordion 

 or Concertina. All the phenomena attending the production of Musical 

 tones are fully explicable on this hypothesis ; except the production of 

 falsetto notes, which has not yet been clearly accounted for. The 

 power which the Will possesses, of determining, with the most perfect 

 precision, the exact degree of tension which these ligaments shall re- 

 ceive, is extremely remarkable. Their average length in the Male, 

 in the state of repose, is estimated by Miiller at about 73-lOOths of an 

 inch ; whilst, in the state of greatest tension, it is about 93-100ths ; the 

 whole difference, therefore, is not above 20-100ths, or one-fifth of an 

 inch. In the female glottis, their average dimensions are about 51- 

 lOOths and 63-100ths, respectively ; so that the difference is here only 

 12-100ths, or less than one-eighth of an inch. Now the natural com- 

 pass of the voice, in most persons who have cultivated the vocal organ, 

 may be stated at about two octaves, or 24 semitones. Within each 

 semitone, a singer of ordinary capability could produce at least ten dis- 

 tinct intervals ; so that, for the total number of intervals, 240 is a very 

 moderate estimate. There must, therefore, be at least 240 different 

 states of tension of the vocal cords, every one of which can be at once 

 determined by the will, when a distinct conception exists of the tone to 

 be produced ( 905) ; and, as the whole variation in their length is not 

 more than one-fifth of an inch, even in Man, the variation required, to 

 pass from one interval to another, will not be more than l-1200th of 

 an inch. And yet this estimate is much below that, which might be 

 truly made from the performance of a practised vocalist. The cele- 

 brated Madame Mara is said to have been able to sound 50 different 

 intervals between each semitone ; the compass of her voice was at least 

 40 semitones, so that the total number of intervals was 2000. The 

 extreme variation in the length of the vocal cords, even taking the 

 larger scale of the Male larynx, not being more than one-fifth of an 

 inch, it may be said that she was able to determine the contractions of 

 her vocal muscles to the ten-thousandth of an inch. 



979. It is on account of the greater length of the Vocal cords, that 

 the pitch of the voice is much lower in Man tjian in Woman : but this 

 difference does not arise until the end of the period of childhood, the 

 size of the larynx being about the same in the Boy and Girl, up to the 

 age of 14 or 15 years, but then undergoing a rapid increase in the 

 former, whilst it remains nearly stationary in the latter. Hence it is 

 that Boys, as well as Girls and Women, sing treble; whilst Men sing 

 tenor, which is about an octave lower than the treble ; or bass, which is 

 several notes lower still. The cause of the variation in the timbre or 

 quality in different voices is not certainly known ; but it appears to be 

 due, in part, to differences in the degree of flexibility and smoothness 

 in the cartilages of the larynx. In women and children, these carti- 

 lages are usually soft and flexible, and the voice is clear and smooth ; 

 whilst in men, and in women whose voices have a masculine roughness, 



