and air and the heat of the sun—­all of which drink greedily—­the river below Assuan is sufficiently great to supply nine millions of people with as much water as their utmost science and energies can draw, and yet to pour into the Mediterranean a low-water surplus current of 61,500 cubic feet per second.  Nor is its water its only gift.  As the Nile rises its complexion is changed.  The clear blue river becomes thick and red, laden with the magic mud that can raise cities from the desert sand and make the wilderness a garden.  The geographer may still in the arrogance of science describe the Nile as ’a great, steady-flowing river, fed by the rains of the tropics, controlled by the existence of a vast head reservoir and several areas of repose, and annually flooded by the accession of a great body of water with which its eastern tributaries are flushed’ [Encyclopaedia Britannica]; but all who have drunk deeply of its soft yet fateful waters—­fateful, since they give both life and death—­will understand why the old Egyptians worshipped the river, nor will they even in modern days easily dissociate from their minds a feeling of mystic reverence.

South of Khartoum and of ‘The Military Soudan’ the land becomes more fruitful.  The tributaries of the Nile multiply the areas of riparian fertility.  A considerable rainfall, increasing as the Equator is approached, enables the intervening spaces to support vegetation and consequently human life.  The greater part of the country is feverish and unhealthy, nor can Europeans long sustain the attacks of its climate.  Nevertheless it is by no means valueless.  On the east the province of Sennar used to produce abundant grain, and might easily produce no less abundant cotton.  Westward the vast territories of Kordofan and Darfur afford grazing-grounds to a multitude of cattle, and give means of livelihood to great numbers of Baggara or cow-herd Arabs, who may also pursue with activity and stratagem the fleet giraffe and the still fleeter ostrich.  To the south-east lies Bahr-el-Ghazal, a great tract of country occupied by dense woods and plentifully watered.  Further south and nearer the Equator the forests and marshes become exuberant with tropical growths, and the whole face of the land is moist and green.  Amid groves of gigantic trees and through plains of high waving grass the stately elephant roams in herds which occasionally number four hundred, hardly ever disturbed by a well-armed hunter.  The ivory of their tusks constitutes the wealth of the Equatorial Province.  So greatly they abound that Emin Pasha is provoked to complain of a pest of these valuable pachyderms [life of Emin Pasha, vol.i chapter ix.]:  and although they are only assailed by the natives with spear and gun, no less than twelve thousand hundredweight of ivory has been exported in a single year [Ibid.] All other kinds of large beasts known to man inhabit these obscure retreats.  The fierce rhinoceros crashes