d,
several ancient sites have been much eroded or destroyed--and the main
volume of the stream may in course of time be diverted into what has
previously been a secondary channel. According to the classical writers,
the mouths or branches of the Nile in the Delta were five in number
(seven including two that were artificial): now there are only two. In
Upper Egypt the main stream tended as now to flow along the eastern edge
of the valley, while to the west was a parallel stream corresponding to
the Bahr Yusuf. From the latter a canal or branch led to the Lake of
Moeris, which, until the 3rd century B.C., filled the deep depression of
the Fayum, but is now represented only by the strongly brackish waters
of the Birket el Kerun, left in the deepest part. The area of alluvial
land has probably not changed greatly in historic times. The principal
changes that have occurred are due to the grip which civilization has
taken upon the land in the course of thousands of years, often weakening
but now firmer than ever. In early days no doubt the soil was cultivated
in patches, but gradually a great system of canals was organized under
the control of the central government, both for irrigation and for
transport. The wild flora of the alluvial valley was probably always
restricted and eventually was reduced almost to the "weeds of
cultivation," when every acre of soil, at one period of the year under
water, and at another roasted under the burning heat of a semi-tropical
sun, was carefully tilled. The acacia abounded on the borders of the
valley, but the groves were gradually cut down for the use of the
carpenter and the charcoal-burner. The desert was full of wild life, the
balance of nature being preserved by the carnivorous animals preying on
the herbivorous; trees watered by soakage from the Nile protected the
undergrowth and encouraged occasional rainfall. But this balance was
upset by the early introduction of the goat and later of the camel,
which destroyed the sapling trees, while the grown ones fell to the axe
of the woodcutter. Thus in all probability the Egyptian deserts have
become far poorer in animals and trees than they were in primitive
times. Much of Lower Egypt was left in a wilder state than Upper Egypt.
The marshy lands in the north were the resort of fishermen and fowlers,
and the papyrus, the cultivation of which was a regular industry,
protected an abundance of wild life. The abandonment of papyrus culture
in t