223 LECTURE VI. 



noise, is deduced from the conformation of the 

 wind-pipe, which in this bird is different from other 

 volatiles. For at the upper extream it hath no fit 

 larynx or throttle to qualify the sound, and at 

 the other end, by two branches deriveth itself into 

 the lungs. Which division consisteth only of 

 semicircular fibres, and such as attain but half 

 way round the part : by which formation they 

 are dilatable into larger capacities, and are able 

 to contain a fuller proportion of air; which being 

 with violence sent up the weazon, and finding no 

 resistance by the larynx, it issueth forth in a 

 sound like that from caverns, and such as some- 

 times subterraneous eruptions from hollow rocks 

 afford. As Aristotle observeth in a problem; and 

 is observable in pitchers, bottles, and that instru- 

 ment which Aponensis upon that problem de- 

 scribeth, wherewith in Aristotle's time gardiners 

 affrighted birds. 



Whether the large perforations of the extre- 

 mities of the weazon, in the abdomen, admitting 

 large quantity of air within the cavity of its mem- 

 branes, as it doth in Frogs, may not much assist 

 this mugiency or boation, may also be considered* 

 For such as have beheld them making this noise 



