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underneath it attracts a bitter moisture that takes
away all the water's taste. For in the sea there are great and
high mountains and deep valleys that are full
of grievous and contaminated bitternesses. The land that
is at the bottom of these valleys emits a scum from the heat of
the sun above it and this mixes with the water so that
it takes on saltiness due to the heat of the sun --
in that the one thing is mixed with the other --
and thus the sea water becomes salty because of the scum.
With this I will end the discussion on the matter of sweet
and salt water and will tell you about air, which is one
of the four elements, and its properties. [rubric] Here speaks of the nature of air.[/rubric]
Air is situated above water and is much more
subtle than either water or earth. It entirely surrounds
the earth, and commands height to such an extent
that the clouds can rise into it. This air, which
surrounds us on all sides, is very thick, and we live in it just
as a fish lives in the water, which takes water in and then spits it out again.
In the same way we benefit from air. For
we take it in and then we push it out again, and in this way we