Meteorology   

into existence and been produced by the river. This is clear from an

observation of the country, and the facts about the Red Sea suffice to

prove it too. One of their kings tried to make a canal to it (for it

would have been of no little advantage to them for the whole region to

have become navigable; Sesostris is said to have been the first of the

ancient kings to try), but he found that the sea was higher than the

land. So he first, and Darius afterwards, stopped making the canal,

lest the sea should mix with the river water and spoil it. So it is

clear that all this part was once unbroken sea. For the same reason

Libya-the country of Ammon-is, strangely enough, lower and hollower

than the land to the seaward of it. For it is clear that a barrier

of silt was formed and after it lakes and dry land, but in course of

time the water that was left behind in the lakes dried up and is now

all gone. Again the silting up of the lake Maeotis by the rivers has

advanced so much that the limit to the size of the ships which can now

sail into it to trade is much lower than it was sixty years ago. Hence

it is easy to infer that it, too, like most lakes, was originally

produced by the rivers and that it must end by drying up entirely.

Again, this process of silting up causes a continuous current

through the Bosporus; and in this case we can directly observe the

nature of the process. Whenever the current from the Asiatic shore

threw up a sandbank, there first formed a small lake behind it.

Later it dried up and a second sandbank formed in front of the first

and a second lake. This process went on uniformly and without

interruption. Now when this has been repeated often enough, in the

course of time the strait must become like a river, and in the end the

river itself must dry up.

So it is clear, since there will be no end to time and the world

is eternal, that neither the Tanais nor the Nile has always been

flowing, but that the region whence they flow was once dry: for

their effect may be fulfilled, but time cannot. And this will be

equally true of all other rivers. But if rivers come into existence