340 VOCAL APPARATUS. L.ECT. XVIII. 



so strong or so distinct as those produced by the impulse of 

 a current of air. Hence, therefore, the second explanation 

 of the sound of the tongue appears more probable than the 

 first. It may, indeed, be replied, that by striking the 

 tongue, we merely shake it, but not long enough to produce 

 a uniform and durable vibratory movement. I do not, 

 however, see why we should refuse to admit the simulta- 

 neous existence of both these causes of sound ; for the 

 tongue would easily, by its transversal vibrations, place 

 itself in unison with the sound produced by the vibrations 

 excited in the air. 



When a sounding tube is added to the reed, we have a 

 reed instrument such as is generally met with; and sounds 

 thus obtained are very different, both in tone and intensity, 

 from those produced by the [reed or] tongue alone. The 

 sound is neither that of the reed nor of the tube alone ; but 

 both become modified, and accord together. I must here 

 explain to you the results obtained by Weber upon this 

 subject. The pipe added to the reed may render the sound 

 of the latter more grave, but never more acute; and the 

 lowering of the pitch thus produced never exceeds an oc- 

 tave. By lengthening the tube, we may again raise the 

 sound to the fundamental primitive pitch of the reed ; and 

 by increasing still farther the length of the tube, the pitch 

 again becomes lowered ; but for this purpose it should be 

 shorter than the first time. The length which it is neces- 

 sary the tube should have, in order to lower the pitch to 

 any given point, constantly depends on the relation which 

 exists between the number of the vibrations which the reed 

 and the tube separately make : thus the sound sinks gradu- 

 ally as the tube is lengthened, until the column of air 

 reaches such a length that it alone would produce the same 

 fundamental sound as the reed itself would give. By again 

 lengthening the tube, the sound sinks to about a fourth, 



