646 On thé Method of judging by the Ear 
to be confined to the opening of the lips; 
There are but few persons, I imagine; who have 
‘not some time or other witnessed an incident, 
which shews the vulgar notion  to'be erronéous in 
this particular. For if a man standing in a close 
apartment should happen to apply his face to a 
loop-hole, or narrow window, in order to speak 
to some person in the open air, a by-stander in 
the room with him will hear his voice, not indeed 
in its natural tone, but as if it were smothered by 
being forced to issue from a hollow case; but 
the circumstance of his words being heard dis- 
tinctly, by one who cannot receive them from 
his mouth, proves the vibrations requisite for 
their production to be conveyed through the 
solid parts of the speaker’s body, agreeably to 
the preceding assertion, The reason why we 
generally conclude the voice to be. confined to 
the opening of the mouth, appears to be this. 
Those pulses which escape from the aperture are 
the strongest, they therefore surpass the weaker 
vibrations of the contiguous parts ; for when a 
number of sounds moving in different directions 
strikes the ear at the same instant, the hearer does 
not notice their several places, but refers all of 
them to the quarter in which the most powerful 
is perceived. For instance, when a man stands 
at a sufficient distance from an extensive obstacle, 
his words are answered by an echo; but let him 
make a loud uninterrupted noise, neither he ‘ugr 
