_MADAM,_
Your desire is to know, why sound is louder in a Vault, and in a large
Room then in a less? I answer, A Vault or arched Figure is the freest
from obstruction, as being without corners and points, so as the
sensitive and rational corporeal motions of the Ear can have a better
perception; like as the Eye can see farthest from a hill then being
upon a level ground, because the prospect is freer from the hill, as
without obstruction, unless it be so cloudy that the clouds do hinder
the perception; And as the eye can have a better prospect upon a hill,
so the ear a stronger perception in a Vault; And as for sound, that it
is better perceived in a large, then in a little close room or place,
it is somewhat like the perception of sent, for the more the odorous
parts are bruised, the stronger is that perception of sent, as being
repeated double or treble, which makes the perception stronger, like as
a thick body is stronger then a thin one; So likewise the perception
of sound in the air; for though not all the parts of the air make
repetitions, yet some or many make patterns of the sound; the truth
is, Air is as industrious to divulge or present a sound, by patterns
to the Ear, as light doth objects to the Eye. But then you may ask me,
Why a long hollow pipe doth convey a voice to the ear more readily,
then any large and open place? My answer is, That the Parts of the
air in a long pipe are more Composed and not at liberty to wander, so
that upon necessity they must move onely to the patterning out of the
sound, having no choice, which makes the sound much stronger, and the
perception of the Ear perfecter; But as for Pipes, Vaults, Prospects,
as also figures presented in a room through a little hole, inverted,
and many the like, belongs more to Artists then to my study, for though
Natural Philosophy gives or points out the Ground, and shews the
reason, yet it is the Artist that Works; Besides it is more proper for
Mathematicians to discourse of, which study I am not versed in; and so
leaving it to them, I rest,
Madam,
_Your faithful Friend_
_and Servant._