WHY THE CURRENT OF GIBRALTAR IS ALWAYS GREATER TO THE WEST THAN TO
THE EAST.

The reason is that if you put together the mouths of the rivers
which discharge into the Mediterranean sea, you would find the sum
of water to be larger than that which this sea pours through the
straits into the ocean. You see Africa discharging its rivers that
run northwards into this sea, and among them the Nile which runs
through 3000 miles of Africa; there is also the Bagrada river and
the Schelif and others. [Footnote 5: _Bagrada_ (Leonardo writes
Bragada) in Tunis, now Medscherda; _Mavretano_, now Schelif.]
Likewise Europe pours into it the Don and the Danube, the Po, the
Rhone, the Arno, and the Tiber, so that evidently these rivers, with
an infinite number of others of less fame, make its great breadth
and depth and current; and the sea is not wider than 18 miles at the
most westerly point of land where it divides Europe from Africa.