58 THE NILE. Inundation.
having begun to subside, it generally rises again for a short time,
sometimes regaining and even passing its first culminating point.
At length it begins to subside steadily, and after a time the de¬
crease becomes more and more rapid. In January, February, and
March the fields from which the water has receded gradually dry
up, and in April, May, and the first few days of June the river is
at its lowest. The height of the inundation most favourable for
agriculture at the present day has been ascertained by long obser¬
vation to be 23 cubits 2 inches (i.e. about 41 ft. 2in., the cubit
being 21.3g6 inches), while in the time of Herodotus 16 cubits suf¬
ficed, and the god of the Nile in the Vatican is therefore repres¬
ented as surrounded by sixteen children. A single cubit more is
apt to cause terrible devastation in the Delta, and elsewhere to cover
many fields destined for the autumn crop (nabdri, p. 74), while a
deficiency of two cubits causes drought and famine in Upper Egypt.
As health depends to a great extent on the regularity of the
pulsations of the heart, so the welfare of the whole of this singular
country is jeopardised by a too powerful or a too scanty flow of the
great artery on which its very existence depends. An excessive
overflow, especially if it does not give notice of its approach in
due time, is far more disastrous now than formerly, as the extensive
cotton-fields in the Delta will not bear flooding, and have to be
protected by embankments.
Egypt is now no longer a vast lake during the inundation as
it formerly was, nor does the overflow of the fields take place in a
direct manner as is commonly supposed. The water is conducted
into a vast network of reservoirs and canals, and distributed as re¬
quired (comp. p. 71), and special engineers are appointed for their
supervision. The whole of the cultivable land is divided into huge
basins, in which the water introduced by the canals is maintained
at a certain height until it has sufficiently saturated the soil and
deposited the requisite quantity of mud. After the water in the
river has subsided, that in the basins may either be discharged into
the river or into the canals, or it may be used for filling other ba¬
sins lying at a lower level. During these operations many of the
villages are connected by means of embankments only, while others
can only be reached by boat, and the whole country presents a
very peculiar and picturesque appearance.
If the river and the system of canals connected with it are in
any way neglected, the consequences are very disastrous, as was
notably the case during the latter part of the Byzantine supremacy
and under the disgraceful sway of the Mamelukes, when the fertile
soil of Egypt yielded less than one-half of its average produce. The
mean difference between the highest and the lowest state of the
river is about 25 ft. at Cairo. 38 ft. at Thebes, and 49 ft. at Assuan.
Even in March and April the traveller will have an opportunity of
observing how powerful and rapid the flow of the river still is