or yellowish tint, according to the nature and colour of the ground, from which the dust arises. The yellow however always, more or less, predominates. In looking through a glass of a light yellow colour, one may form a pretty correct idea of the appearance of the air, as I observed it during a stormy Semoum at Esne, in Upper Egypt, in May 1813. The Semoum is not always accompanied by whirlwinds; in its less violent degree it will blow for hours with little force, although with oppressive heat; when the whirlwind raises the dust it then encreases several degrees in heat. In the Semoum at Esne the thermometer mounted to 121° in the shade, but the air seldom remains longer than a quarter of an hour in that state, or longer than the whirlwind lasts. The most disagreeable effect of the Semoum on man is, that it stops perspiration, dries up the palate, and produces great restlessness. I never saw any person lie down flat upon his face to escape its pernicious blast, as Bruce describes himself to have done in crossing this desert; but during the whirlwinds the Arabs often hide their faces with their cloaks, and kneel down near their camels to prevent the sand or dust from hurting their eyes. Camels are always much distressed, not by the heat but by the dust blowing into their large, prominent, eyes. They turn round and endeavour to screen themselves by holding down their heads, but this I never saw them do except in case of a whirlwind, however intense the heat of the atmosphere might be. In June 1813, going from Esne to Siout, a violent Semoum overtook me upon the plain between Farshiout and Berdys. I was quite alone, mounted upon a light-footed Hedjin. When the whirlwind arose neither house nor tree was in sight, and while I was endeavouring to cover my face with my handkerchief, the beast was made unruly, by the quantity of dust blown into its eyes, and the terrible noise of the wind, and set off at a furious gallop; I lost the reins and received a heavy fall, and not being able to see ten yards before me, I remained wrapped up in my cloak on the spot where I fell, until the wind abated, when pursuing my dromedary, I found it at a great distance, quietly standing near a low shrub, the branches of which afforded some shelter to its eyes. Bruce has mentioned the moving pillars of sands in this desert, but although none such occurred during my passage, I do not presume to question his veracity on this head. The Arabs told me that there are often whirlwinds of sand, and I have repeatedly passed through districts of moving sands, which the slightest wind can raise; I remember to have seen columns of sands moving about like water spouts in the desert on the banks of the Euphrates, and have seen at Jaka terrible effects from a sudden wind; I therefore very easily credit their occasional appearance in the Nubian desert, although I doubt of their endangering the safety of travellers.