eye may be judge, iron must be reckoned
to have a great many vacuities, and to be porous like a honey-comb, yet
it is the dullest, and sounds worse than any other metal.

Therefore there is no need to trouble the night to contract and condense
its air, that in other parts we may leave vacuities and wide spaces; as
if the air would hinder and corrupt the substance of the sounds, whose
very substance, form, and power itself is. Besides, if your reason held,
misty and extreme cold nights would be more sonorous than those which
are temperate and clear, because then the atoms in our atmosphere are
constipated, and the spaces which they left remain empty; and, what is
more obvious, a cold day should be more sonorous than a warm summer's
night; neither of which is true. Therefore, laying aside that
explication, I produce Anaxagoras, who teacheth that the sun makes a
tremulous motion in the air, as is evident from those little motes which
are seen tossed up and down and flying in the sunbeams. These (says he),
being in the day-time whisked about by the heat, and making a humming
noise, lessen or drown other sounds; but at night their motion, and
consequently their noise, ceaseth.

When I had thus said, Ammonius began: Perhaps it will look like a
ridiculous attempt in us, to endeavor to confute Democritus and correct
Anaxagoras. Yet we must not allow that humming noise to Anaxagoras's
little motes, for it is neither probable nor necessary. But their
tremulous and whirling motion in the sunbeams is oftentimes sufficient
to disturb and break a sound. For the air (as hath been already said),
being itself the body and substance of sound, if it be quiet and
undisturbed, makes a straight, easy, and continuous way to the particles
or the motions which make the sound. Thus sounds are best heard in calm
still weather; and the contrary is seen in stormy weather, as Simonides
hath it:--

No tearing tempests rattled through the skies,
Which hinder sweet discourse from mortal ears.

For often the disturbed air hinders the articulateness of a discourse
from coming to the ears, though it may convey something of the loudness
and length of it. Now the night, simply considered in itself, hath
nothing that may disturb the air; though the day hath,--namely the sun,
according to the opinion of Anaxagoras.

To this Thrasyllus, Ammonius's son, subjoining said: What is the
matter, for God's sake, that we endeavor to solve this difficult