PHYSIOGRAPHY OF EASTERN PERSIA. 22/ 
CLIMATE : THE CAUSE OF 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 lo 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 1 2 inches a year the region is 
reduced to a desert and the water supply is too small to be of sen,'ice 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 gen- 
erally a tolerably- heavy fall of snow, and another in February, followed b>- showers 
in March and the beginning of April, after w-hich there is nothing but an occasional 
thunder stonn 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. Moreo\-er, the high mountains which 
border Persia on even,- side shut out the moisture of the sea and shut in the people. 
The prevailing winds of Eastern Persia bring \-er)- 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 correspondinglv decreased. 
The moisture picked up in crossing the Black and Caspian seas is deposited in the 
lofty Annenian 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 w-hich circle round the Asiatic center of low barometric 
pressure far to the northeast, and guided by the north-northwest trend of the moun- 
tains of Eastern Persia produces dry winds of the most extraordinary strength and 
constancy. Holdich (pp. 145, 334) describes their occun'ence in northwestern 
Afghanistan and northwestern Baluchistan, but they- are most violent at Sistan, half- 
way between the tw-o. 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 60 to 80 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 stonn. The con- 
tinual hum, 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 
