The Black Sea
The sea called "The Pontus" has a circumference of
note
twenty-two thousand stades, and two mouths
diametrically opposite to each other, the one
opening into the Propontis and the other into the Maeotic
Lake; which latter also has itself a circumference of eight
thousand stades. Into these two basins many great rivers
discharge themselves on the Asiatic side, and still larger
and more numerous on the European; and so the
Maeotic lake, as it gets filled up, flows into the Pontus,
and the Pontus into the Propontis. The mouth of the
Maeotic lake is called the Cimmerian Bosporus, about
thirty stades broad and sixty long, and shallow all over; that
of the Pontus is called the Thracian Bosporus, and is a
hundred and twenty stades long, and of a varying breadth.
Between Calchedon and Byzantium the channel is fourteen
stades broad, and this is the entrance at the end nearest the
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Propontis. Coming from the Pontus, it begins at a place
called Hieron, at which they say that Jason on his return
voyage from Colchis first sacrificed to the twelve gods. This
place is on the Asiatic side, and its distance from the European
coast is twelve stades, measuring to Sarapieium, which lies
exactly opposite in Thrace. There are two causes which account
for the fact that the waters, both of the Maeotic lake and the
Pontus, continually flow outwards. One is patent at once to
every observer, namely, that by the continual discharge of
many streams into basins which are of definite circumference and
content, the water necessarily is continually increasing in bulk,
and, had there been no outlet, would inevitably have encroached
more and more, and occupied an ever enlarging area in the
depression: but as outlets do exist, the surplus water is carried
off by a natural process, and runs perpetually through the
channels that are there to receive it. The second cause is the
alluvial soil brought down, in immense quantities of every
description, by the rivers swollen from heavy rains, which
forms shelving banks and continually forces the water to take
a higher level, which is thus also carried through these outlets.
Now as this process of alluvial deposit and influx of water is
unceasing and continuous, so also the discharge through the
channels is necessarily unceasing and continuous.
These are the true causes of the outflow of the Pontus,
which do not depend for their credit on the stories of
merchants, but upon the actual observation of nature, which is
the most accurate method discoverable.
