Part IL in the Ckeatio^. 263 



therefore if the Auricula be cut clear off the 

 Hearing is much impaired, and almoft quite 

 marr'd, as hath been by Experience found. From 

 the Auricula is extended a fmall, long, round 

 Hole inward into the Head, to intend the Mo- 

 tion, and fo augment the Force of the Sound, as 

 we fee in a Shooting-Trunk, the longer it is to a 

 certain Limit, the fwifter and more forcibly the 

 Air paiTes in it and drives the Pellet. At the end 

 of this Hole is a Membrane faften'd to a round 

 boney Limb, and ftretch'd like the Head of a 

 Drum, and therefore by Ana torn ifts call'd alfo 

 Tympanum^ to receive the Impulfe of the Sound, 

 and to vibrate or quaver according to its recipro- 

 cal Motions or Vibrations ; the fmall Ear-bones 

 being at the end faften'd to the Tympanum^ and 

 furnifh'd with a Mufcle, ferve for the Tenlion 

 of that Membrane, or the Relaxation of it, ac- 

 cording to the Exigency of the Animal, it being 

 ftretch'd to the utmoft when it would hearken 

 diligently to a lower or more diftant Sound. Be- 

 hind the Drum are feveral Vaults and anfraduous 

 Cavities in the Ear-bone, fiU'd only with what 

 Naturalifts call the implanted Air, fo to intend 

 the leaft Sound imaginable that the Senfe might 

 be affected with it ; as we fee in fubterraneous 

 Caves and Vaults how the Sound is redoubled, 

 and what a great Report it makes however mo- 

 derate it be ; and becaufe it was for the behoof 

 of the Animal^ that upon any fudden Accident it 

 might be awaken'd out of its Sleep, therefore 



S 4 were 



