we had suddenly arrived upon the edge of a deep valley, between five and
six miles wide, at the bottom of which, about two hundred feet below the
general level of the country, flowed the river Atbara. On the opposite
side of the valley the same vast table-lands continued to the western
horizon.

We commenced the descent toward the river: the valley was a succession
of gullies and ravines, of landslips and watercourses. The entire
hollow, of miles in width, had evidently been the work of the river. How
many ages had the rains and the stream been at work to scoop out from
the flat tableland this deep and broad valley? Here was the giant
laborer that had shovelled the rich loam upon the delta of Lower Egypt!
Upon these vast flats of fertile soil there can be no drainage except
through soakage. The deep valley is therefore the receptacle not only
for the water that oozes from its sides, but subterranean channels,
bursting as land-springs from all parts of the walls of the valley, wash
down the more soluble portions of earth, and continually waste away the
soil. Landslips occur daily during the rainy season; streams of rich
mud pour down the valley's slopes, and as the river flows beneath in
a swollen torrent, the friable banks topple down into the stream and
dissolve. The Atbara becomes the thickness of peasoup, as its muddy
waters steadily perform the duty they have fulfilled from age to age.
Thus was the great river at work upon our arrival on its bank at the
bottom of the valley. The Arab name, "Bahr el Aswat" (black river) was
well bestowed; it was the black mother of Egypt, still carrying to her
offspring the nourishment that had first formed the Delta.

At this point of interest the journey had commenced; the deserts were
passed; all was fertility and life. Wherever the sources of the
Nile might be, the Atbara was the parent of Egypt! This was my first
impression, to be proved hereafter.

A violent thunderstorm, with a deluge of rain, broke upon our camp on
the banks of the Atbara, fortunately just after the tents were pitched.
We thus had an example of the extraordinary effects of the heavy rain in
tearing away the soil of the valley. Trifling watercourses were swollen
to torrents. Banks of earth became loosened and fell in, and the rush
of mud and water upon all sides swept forward into the river with a
rapidity which threatened the destruction of the country, could such a
tempest endure for a few days. In a cou