M. Savart on the Mechanism of the Human Voice. 201 



fifth, although there is always one sound which is given out 

 more easily, and which is more pure and more intense than 

 all the others. 



The hunters, in order to imitate the voices of certain birds, 

 employ a small instrument, in which the current of air exerts 

 an influences till more considerable. This instrument, made 

 of bone, wood, or metal, has commonly the form of a small 

 cylindrical tube about 8-10ths of an inch in diameter, and 

 3— lOths high. At each of its ends it is shut up by a thin 

 and smooth plate perforated at its centre, with a hole about 

 1| tenths in diameter. Sometimes it has the form shown in 

 Plate V. Fig 1, which is the section of a hemispherical vase 

 with two opposite orifices. The hunters place this instru- 

 ment between the teeth and the lips, and by drawing in the 

 air with more or less force through the two orifices, they suc- 

 ceed in obtaining different sounds. 



This effect may be produced with more certainty, by 

 adding to it a cylindrical portvent, as in Fig. 2. By this means, 

 we may obtain all sounds comprised in an extent of an octave 

 and a half to two octaves, passing, in general, through the in- 

 terval from at G to ut A . The gravest sounds are generally dull 

 and feeble, and the most acute are unsupportably piercing. 

 The sounds become more grave by increasing the orifices. 



The sounds produced in this instrument seem to arise from 

 this, — that the current of air which passes through the two 

 orifices, dragging along with it the small mass of fluid con- 

 tained in the cavity, diminishes its elastic force, and, conse- 

 quently; destroys its equilibrium with the pressure of the ex- 

 ternal air, which, reacting upon it, drives it back, and com- 

 presses it till, by its own elasticity, and under the influence 

 of the continued current, it undergoes a new rarefaction, fol- 

 lowed by a second condensation, and so on continually. 

 These ultimate states of rarefaction and condensation being 

 sufficiently near one another, ought to give rise to waves, 

 which, spreading out in the external air, produces the sensation 

 of a determinate sound. It ought also to be noticed, that the 

 thinner the sides of the whistle are, they vibrate with more 

 energy, and if, in a hemispherical one, we replace the plam; 



