The often-described _simoon_ of the desert is an intensely heated and dry wind, which raises the temperature like the blast of a furnace, and fills the air with particles of sand, of suffocating quality. The same wind is known in the deserts of Turkestan as the _tebbad_ (fever-wind), the terrible conditions of which are thus described by the pen of a traveler. “The kervanbashi (_leader of the caravan_) and his people drew our attention to a cloud of dust that was approaching, and told us to lose no time in dismounting from the camels. These poor brutes knew well enough that it was the _tebbad_ that was hurrying on; uttering a loud cry they fell on their knees, stretched their long necks along the ground, and strove to bury their heads in the sand. We intrenched ourselves behind them, lying there as behind a wall; and scarcely had we, in our turn, knelt under their cover, than the wind rushed over us with a dull, clattering sound, leaving us, in its passage, covered with a crust of sand two fingers thick. The first particles that touched me seemed to burn like a rain of flakes of fire. Had we encountered it when we were deeper in the desert we should all have perished. I had not time to make observations upon the disposition to fever and vomiting caused by the wind itself, but the air became heavier and more oppressive than before.” The _sirocco_ of the Mediterranean coasts is the hot wind of the African desert, tempered, before reaching the coasts of southern Europe, by its passage across the great expanse of inland waters. The enervating influences of this wind are well known to the resident on the shores of Sicily, the Italian mainland, or the islands of the Archipelago. The same wind, when it reaches the high mountain regions of the Apennines and the Alps, is known as the föhn. The _föhn_, or warm south wind, is an important agent in modifying the climate of the higher Alpine region, where its prevalence for a few days in succession causes the snow-line to recede, and is often accompanied by inundations occasioned by the suddenly melted snows. Its absence during a longer period than usual is attended, on the other hand, by a prolongation of the glaciers into a lower region of the mountain valleys. The Swiss peasants have a saying, when they talk of the melting of the snow, that the sun could do nothing without the föhn. The _harmattan_ of Senegambia and Guinea is a cold and intensely dry wind, which blows from the northeast during the months of December and January. The _mistral_ of southern France possesses similar qualities to the last-named wind, and blows, for days together, down the valley of the Rhone.