CLIMATE : THE CAUSE OIL THE DESOLATION OF PERSIA.
The main cause of the desert condition of Persia is its climate. The rainfall of the country as a whole is estimated as averaging not over io inches a year. Throughout the greater portion of central and southeastern Persia and the adjoining portions of Afghanistan and Baluchistan the annual rainfall can not be much more than 5 inches. (St. John, p. 7.) The extreme paucity of this will be realized when it is remembered that when the rainfall is less than 12 inches a year the region is reduced to a desert and the water supply is too small to be of service in irrigation, except in small areas or on the banks of large rivers. The scanty rainfall is usually divided as follows, according to St. John (p. 7) : "A little rain is hoped for, but not always expected, in November, to sow the early crops. In December there is generally a tolerably heavy fall of snow, and another in February, followed by showers in March and the beginning of April, after which there is nothing but an occasional thunder storm in the mountains till the next winter."
This woful aridity is due partly to Persia's continental position and partly to the high mountains which hem it in. Although 36 per cent of the Persian frontier is bordered by salt water, the country is distinctly continental in climate and in the character of its people. Only the 7 per cent of seacoast in the southeast corner along the Indian Ocean is exposed to the open sea, while the remaining 29 per cent faces the inclosed Caspian Sea and the Persian Gulf, which have little influence in producing a marine climate or people. Moreover, the high mountains which border Persia on every side shut out the moisture of the sea and shut in the people.
The prevailing winds of Eastern Persia bring very little rain, as they come from the north and northwest, from a continental region. They flow into districts of increasing warmth, where their capacity for holding and absorbing moisture is continually increased and the tendency to furnish rain correspondingly decreased. The moisture picked up in crossing the Black and Caspian seas is deposited in the lofty Armenian highland and Elburz range, and little is left for the thirsty lands beyond. In summer the northward prolongation of the trade winds combines with the spirally inflowing winds which circle round the Asiatic center of low barometric pressure far to the-northeast, and guided by the north-northwest trend of the mountains of Eastern Persia produces dry winds of the most extraordinary strength and constancy. Holdich (pp. 145, 334) describes their occurrence in northwestern Afghanistan and northwestern Baluchistan, but they are most violent at Sistan, halfway between the two. According to the British members of the Sistan Arbitration Commission, this wind, called the "Wind of One Hundred and Twenty Days," blows almost continuously day and night during the four hottest months of the year, much of the time at the hurricane rate of from 6o to 8o miles per hour. Dust and sand fill the air. The double-pegged tents which withstand the blast make a noise like that of the rigging of a ship in the wildest storm. The continual Buns, flap, clatter, rattle, bang, make mental work almost impossible.
Yet the wind has its beneficial aspect. In the houses of the rich an open doorway in the north side is stuffed with small brush. Upon this a servant throws