I DEDICATE THIS BOOK,
WITH SPECIAL PERMISSION,
TO HIS ROYAL HIGHNESS ALBERT EDWARD,
PRINCE OF WALES,
AS THE FIRST OF
ENGLAND'S ROYAL RACE
WHO HAS SAILED UPON THE WATERS OF
THE NILE;
THE LAKE SOURCES OF WHICH MIGHTY RIVER ARE HONOURED
BY THE NAMES OF
HIS AUGUST PARENTS.
PREFACE.
THE work entitled "The Albert N'yanza Great Basin of the Nile,"
published in 1866, has given an account of the equatorial lake
system from which the Egyptian river derives its source. It has
been determined by the joint explorations of Speke, Grant, and
myself, that the rainfall of the equatorial districts supplies
two vast lakes, the Victoria and the Albert, of sufficient volume
to support the Nile throughout its entire course of thirty
degrees of latitude. Thus the parent stream, fed by never-failing
reservoirs, supplied by the ten months' rainfall of the equator,
rolls steadily on its way through arid sands and burning deserts
until it reaches the Delta of Lower Egypt.
It would at first sight appear that the discovery of the lake
sources of the Nile had completely solved the mystery of ages,
and that the fertility of Egypt depended upon the rainfall of the
equator concentrated in the lakes Victoria and Albert; but the
exploration of the Nile tributaries of Abyssinia divides the Nile
system into two proportions, and unravels the entire mystery of
the river, by assigning to each its due share in ministering to
the prosperity of Egypt.
The lake sources of Central Africa support the life of Egypt, by
supplying a stream, throughout all seasons, that has sufficient
volume to support the exhaustion of evaporation and absorption;
but this stream, if unaided, could never overflow its banks, and
Egypt, thus deprived of the annual inundation, would simply
exist, and cultivation would be confined to the close vicinity of
the river.
The inundation, which by its annual deposit of mud has actually
created the Delta of Lower Egypt, upon the overflow of which the
fertility of Egypt depends, has an origin entirely separate from
the lake-sources of Central Africa, and the supply of water is
derived exclusively from Abyssinia.
The two grand affluents of Abyssinia are, the Blue Nile and the
Atbara, which join the main stream respectively in N. lat. 15
degrees 30 minutes and 17 degrees 37 minutes. These rivers,
although streams of extreme grandeur during the period of the
Abyssinian rains, from the middle of June until September, are
reduced during the dry months to utter insignificance; the Blue
Nile becoming so shallow as to be unnavigable, and the Atbara
perfectly dry. At that time the water supply of Abyssinia having
ceased, Egypt depends solely upon the equatorial lakes and the
affluents of the White Nile, until the rainy season shall again
have flooded the two great Abyssinian arteries. That flood occurs
suddenly about the 20th of June, and the grand rush of water
pouring down the Blue Nile and the Atbara into the parent
channel, inundates Lower Egypt, and is the cause of its extreme
fertility.
