THE CLIMATE. 279 wor.d. From the southern frontier of Nubia, where the tropical rains begin to fall, to the table-land of Abyssinia on the south, and as far up the White Nile as has yet been explored, Scudan is devastated by fevers of the most malignant character. The summers are fatal to at least one-half of the Turks, Egyptians and Europeans who make their residence there, and the natives themselves, though the mortality is not so great among them, rarely pass through the year without an attack of fever. I arrived during the most healthy part of the year, and yet of all the persons I saw, three-fourths were complaining of some derangement of the system. The military hospital, which I visited, was rilled with cases of fever, dysentery and small-pox. I was in such good bodily condition from my journey through the Desert that I could scarcely conceive the sensation of sickness, and the generous diet and invigorating exercise I enjoyed secured me from all fear of an attack.

Travellers are not agreed as to the cause of this mortality in Soudan. Some attribute it to the presence of infusorise in the water ; yet we drank the pure, mountain-born flood of the Blue Nile, and filtered it beforehand. I am disposed to side with Russegger, who accounts for it entirely by the miasma arising from decayed vegetation, during the intense heats. The country around Khartoum is a dead level ; the only mountain to be seen is the long ridge of Djebel Gerrari, twelve miles to the north. Behind the town, the White Nile curves to the east, and during the inundation his waters extend even to the suburbs, almost" insulating the place. The unusual sickness of the winter of 1852 might be accounted for by the inundation of the previous summer, which waa so much higher than ordinary that the people were obliged to erect dykes to keep the water