Upper Egypt, that is, the cultivated part of it, is a narrow stripe, laid out sometimes on one and sometimes on both sides of the Nile, which, in its course from Abyssinia till it passes Cairo, is on both sides enchained with a ridge of mountains. Lower Egypt is, in general, a fine, rich, flat, country, interspersed in different places by branches of the Nile, and overflown by this river at a particular season; at which time the country is in the situation of Holland, or of the fenny counties of England. The soil in most places is argillaceous or sandy, and in some calcareous; but every where there is a strong mixture of a salt: in most places there are incrustations of it to some depth. The quality of the atmosphere, and the proportions of its different constituent parts, I regret that I never had an opportunity of ascertaining. The cultivated part of Egypt, particularly the Delta, is a very rich country; in fertility and luxuriance of soil yielding to none under the face of heaven. The art of husbandry is there but imperfectly known; and at their harvests there is a very great destruction of vegetable matter, from which hydrogene gas, or hydro-carbonate, is extricated in great quantities. Under similar circumstances, in America as well as in India, I have seen a bad fever of the intermittent or remittent type appear. But in Egypt, after the subsiding of the Nile, which in many places had covered a great extent of country, there is a great exhalation from the mud, and from the putrid animal and vegetable matters left behind. The effluvia of these substances, acting on the human body, will readily account for much disease. If we add to these the extreme filth of the inhabitants of Egypt, their poor diet, their narrow, close, and ill-ventilated, apartments, generally much crouded, with the extreme narrowness of their streets, and the bad police of their towns, we will not be astonished if a fever, at first intermittent or remittent, should have symptoms denominated malignant, superadded to the more ordinary symptoms of the disease. If an imported contagion should make its appearance at the same time, and under the above circumstances, we expect a most terrible disease. The dry parching wind, which comes over the desert, and which at certain seasons blows in Egypt and in Arabia, is well known, and was often severely felt by the army on their march, both across the desert and the isthmus of Suez. The whirlwinds of sand roll with great impetuosity, are very troublesome, and insinuate fine sand and dust every where. It is hardly possible to keep the minute particles out of the eyes.