CENTURY II. 99 



cutteth the air so sharp, as it returneth too swift to 

 make the sound equal : and therefore a mean or 

 tenor is the sweetest part. 



174. We know nothing that can at pleasure 

 make a musical or immusical sound by voluntary 

 motion, but the voice of man and birds. The cause 

 is, no doubt, in the weasond or windpipe, which we 

 call &quot; aspera arteria,&quot; which being well extended, 

 gathereth equality ; as a bladder that is wrinkled, 

 if it be extended, becometh smooth. The extension 

 is always more in tones than in speech : therefore 

 the inward voice or whisper can never give a tone. 

 And in singing, there is, manifestly, a greater work 

 ing and labour of the throat, than in speaking ; as 

 appeareth in the thrusting out or drawing in of the 

 chin, when we sing. 



175. The humming of bees is an unequal buz 

 zing, and is conceived by some of the ancients not 

 to come forth at their mouth, but to be an inward 

 sound ; but, it may be, it is neither ; but from the 

 motion of their wings : for it is not heard but when 

 they stir. 



176. All metals quenched in water give a sibi- 

 lation or hissing sound, which hath an affinity with 

 the letter Z, notwithstanding the sound be created 

 between the water or vapour, and the air. Seething 

 also, if there be but small store of water in a vessel 

 giveth a hissing sound ; but boiling in a full vessel 

 giveth a bubbling sound, drawing somewhat near to 

 the cocks used by children. 



177. Trial would be made, whether the inequa- 



