l^s Dr. Young's Experiments and Inquiries 



upon increasing the tension, and the velocity of the breath, this 

 clicking is lost, -and the sound becomes continuous, but of an 

 extremely grave pitch : it may, by a good ear, be distinguished 

 two octaves below the lowest A of a common bass voice, con- 

 sisting 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 orifice of the larynx, formed by the 

 summits of the arytenoid cartilages and the epiglottis, seems to 

 succeed to the office of the ligaments of the glottis, and to pro- 

 duce a retrograde falsetto, which is capable of a very great 

 degree of acuteness. The same difference probably takes place 

 between the natural voice and the common falsetto : the rimula 

 glottidis being too long to admit of a sufficient degree of tension 

 for very acute sounds, the upper orifice of the larynx supplies 

 its place ; hence, taking a note within the compass of either 

 voice, it may be held, with the same expanse of air, two or three 

 times as long in a falsetto as in a natural voice; hence, too, 

 the difficulty of passing smoothly from the one voice to the 

 other. It has been remarked, that the larynx is always elevated 

 when the sound is acute: but this elevation is only necessary in 

 rapid transitions, as in a shake ; and then probably because, by 

 the contraction of the capacity of the trachea, an increase of the 

 pressure of the breath can be more rapidly effected this way, 

 than by the action of the abdominal muscles alone. The reflec- 

 tion of the sound thus produced from the various parts of the 

 cavity of the mouth and nostrils, mixing at various intervals 

 with the portions of the vibrations 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 vibra- 



