PERSIA. 129 



Chorassan, during the years 1870-72, was not less than 120,000 persons, 

 which would be about one in .seven of the entire population. 



The reasons which have been assigned by various authors for the evident 

 desiccation of Persia will, like those having reference to the Aralo-Caspian 

 depression, come up for consideration farther on. At present, it will be 

 desirable to give only one more quotation, from a highly scientific authoritj', 

 that of W. T. Blanford, tlie geologist of the Anglo-Persian Boundary Com- 

 mission, and the present chief of the India Geological Survey : " From the 

 accounts given by ancient writers it appears highly probable that the popu- 

 lation of Persia Avas much greater, and the cidtivated land far more exten- 

 sive, 2,000 years ago, than at present ; and this may have been due to the 

 country being more fertile in con.sequence of the rainfall being greater. 

 Some alteration may be due to the extirpation of trees and bushes ; but this 

 alone will scarcely account for the change which has taken place. I cannot 

 but think it probable that a gradual change in the climate of Central Asia 

 generally has taken place from the time when the great plain north of Per- 

 sia was under water, when the Black, Caspian, and Aral Seas were united, 

 and when, as Loftus has shown, the plains of Mesopotamia were a part of the 

 Persian Gulf, tliis gradual drying up of the country being thus connected 

 with the elevation of the steppe-region of Central Asia, and of the northern 

 coasts of Persia. To this gradual reduction in the rainfall of modern times 

 is probably to be attributed the circumstance of the Oxus no longer reach- 

 ing the Caspian, and the diminished volume of that river; for I cannot but 

 suspect that the diversion of the Oxus from the Caspian to the Aral Sea in 

 the sixth, and again in the sixteenth century, was but the last in a series of 

 changes in a stream which once, in all probability, carried the surplus waters 

 of the Aral Sea to the Caspian. To the same cause is probably due the 

 gradual diminution of the Caspian and the Sea of Aral; and hence the dis- 

 appearance of the lakes which once. I believe, covered no small part of the 



interior of Persia But for inland seas and lakes to have occupied the 



interior of Persia, and for large deposits to have formed in them, it is evident 

 that the climate must have been mucli damper than at present. In recent 

 times the rainfall has been insufficient to supply water either to fill the 

 basins, or, as we have seen, to wash down the detritus which accumulates at 

 the foot of the hills."* 



* See, Quarterly Journal Geological Society, London, Vol. XXIX. (1873), p. 493, an article entitled " Ou the 

 Nature and Probable Origin of the Superlicial Deposits in the Valleys and Deserts of Central Persia." 



