401. In the south of Europe north winds are notorious for their violence. The great differences of the temperature of the Alps, the Mediterranean, and Africa explain them; and when the polar current, with high atmospheric pressure generally accompanying it, is descending at the same time over Europe, the effect is greatly heightened. Of these the most noted is the Bora, which, descending from the Julian Alps, sweeps over the Adriatic—the bitterly cold tempestuous wind of that much-vexed sea. It is probably the Euroclydon of the Acts. The Mistral is a steady violent north-west wind which blows from France down on the Gulf of Lyons. There are other winds of a stormy character peculiar to different parts of the Mediterranean, such as the Levanter in the east. The heating of the Sahara in summer causes a general and continued flow of the cooler air of the Mediterranean to the south to take the place of the heated air which rises from the sandy desert. These are the Etesian winds of Southern Europe. mounds of sand are transported from place to place by the terrible energy of the tempest. By these mounds of sand, large caravans are frequently destroyed ; and even great armies have been overwhelmed by them, as in the case of Cambyses, who was overtaken by the simoom on his march through the desert to pillage the temple of Jupiter Ammon, and perished with 50,000 of his troops. The destruction of Sennacherib's army is supposed to have been caused by the simoom. The simoom generally lasts from six to twelve hours, but sometimes for a shorter period. 397. Hot winds from Africa are felt in neighbouring regions, where they are known under different names. They are subject to important modifications by the nature of the earth's surface over which they pass. The Sirocco blows occasionally over Sicily, South Italy, and adjoining districts. It is a hot moist wind, receiving its heat from the Sahara, and acquiring its moisture in its passage northward over the Mediterranean. It is the plague of the Two Sicilies; and while it lasts, a haze obscures the atmosphere, and so great is the fatigue which it occasions, that the streets of Palermo become quite deserted. This wind sometimes extends to the shores of the Black and Caspian Seas, and to the steppes beyond the Volga, the seat of the dreaded rinderpest, where, by its blighting touch, vegetation withers and dries up, and thousands of cattle are cut off. It is called the Samiel in Turkey, from its reputed, poisonous qualities. 398. The Solano of Spain is a south-east wind, extremely hot, and loaded with fine dust. It prevails at certain seasons in the plains of Mancha and Andalusia, particularly at Seville and Cadiz. It produces dizziness, and heats the blood to an unusual degree, causing great uneasiness and irritation; hence the Spanish proverb, “ Ask no favour during the solano.” 399. The Harmattan of Guinea and Senegambia belongs to the same class of winds. It is a periodical wind blowing from the dry desert of Africa to the Atlantic, from N. lat. 15° to S. lat, 1°, during December, January, and February. It blows with moderate force, is often highly charged with fine particles of dust, and since under its influence no dew falls, vegetation grows languid and withers. 400. The Pampero is a wind which blows chiefly in the summer season from the Andes across the pampas of Buenos Ayres to the sea-coast. It is thus a north-west wind, or part of the anti-trade of the southern hemisphere, and in this respect it is analogous to the stormy winds which sweep over Europe from the south-west. But since it blows from the Andes over the South American continent, it is a dry wind, frequently darkening the sky with clouds of dust, and drying up the vegetation of the pampas. 401. In the south of Europe north winds are notorious for their violence. The great differences of the temperature of the Alps, the Mediterranean, and Africa explain them; and when the polar current, with high atmospheric pressure generally accompanying it, is descending at the same time over Europe, the effect is greatly heightened. Of these the most noted is the Bora, which, descending from the Julian Alps, sweeps over the Adriatic—the bitterly cold tempestuous wind of that much-vexed sea. It is probably the Euroclydon of the Acts. The Mistral is a steady violent north-west wind which blows from France down on the Gulf of Lyons. There are other winds of a stormy character peculiar to different parts of the Mediterranean, such as the Levanter in the The heating of the Sahara in summer causes a general and continued flow of the cooler air of the Mediterranean to the south to take the place of the heated air which rises from the sandy desert. These are the Etesian winds of Southern Europe. CHAPTER X. STORMS. 2 402. STORMs are violent commotions of the atmosphere, occurring in all climates, and differing from other atmospheric disturburbances in their destructive power and the extent over which they spread. There is, perhaps, no question in physical science in which there has been so large an admixture of speculation with fact as in the attempts made to reduce the phenomena attendant on storms to general laws; the reason being, that meteorological observations were too few in number, and too far apart, to enable any one to give the atmospheric pressure, the general course of the winds, the temperature, and the rainfall, without drawing largely on conjecture. Now, however, owing to the growing popularity of meteorology, and the countenance happily given to it by most civilised nations, sufficient data may be obtained for a fuller and more satisfactory statement of the question. I shall first state the chief facts of observation regarding storms as obtained from synchronous charts of the weather over a considerable portion of the globe ; and as such charts present the principal elements of the weather at a given instant, they may be regarded as successive photographs of storms in their passage across the earth’s surface. Storms of Europe. 403. I have charted about a hundred European storms, laying down in all cases the isobarometric lines, or lines of equal atmospheric pressure,* and the direction and force of the winds, and, in a * In place of lines of equal barometric pressure, many Continental meteorologists give lines of equal barometric disturbance—that is, the difference between the barometer on the particular day, and the mean height of the barometer for the place and season. As this method can only suit a limited space of the earth's surface, it ought to be discarded. Thus, suppose on |