1919. | Seistan and the Helmand. 13 
While we were staying there the wind dropped and there was a 
dead calm for three days. The wind had previously been blowing 
from the north, the direction roughly from the point at which the 
Helmand enters the lake, and the water of the Hamun had been 
quite fresh to the taste. As soon as the Helmand water, however, 
ceased to be blown in our direction, that of the Hamun became 
perceptibly brackish. As the present Hamun system has an 
occasional outlet into the Gaud-i-Zirreh and its waters remain, at 
any rate in the Hamun-i-Sabari, fairly fresh because of the scouring 
of the floods, we may suppose that the salts in the soil round the 
basin near Lab-i-Baring are derived from an old lake which had 
no outlet of the kind. 
There is much historical evidence that the outflow of the 
Helmand has moved northwards in recent times. For example, 
there are ruined cities in the south of Seistan where there is now 
no water at all, while ruins are exposed in the bed of the Hamun- 
i-Sabari in times of exceptionally low water. In its course through 
the desert the river has gradually cut for itself a deep bed. Before 
it did so its course may have been quite other than it is now, and 
the filling up and desiccation of lake-beds may have been corre- 
lated in a complex manner with changes in level. It is by no 
means improbable on general grounds that the river, as the Jordan 
does now, once terminated in a saline lake which was practically 
lifeless. Indeed, there is evidence that it did so in the historical 
period. I have to thank Mr. Vredenburg for the following note 
on this point :— 
“With regard to the change in the course of the Helmand, it 
seems possible that the northward bend at the Band-i-Kamal Khan 
may be partly artificial. From the historical evidence of Arab 
geographers, this spot must correspond with the original head of 
the delta which, originally, therefore, would have spread mainly 
over Southern Seistan and would have communicated more directly 
than it does now with the Zirreh Lake. It is nevertheless con- 
ceivable that the diversion may have been natural or partly 
natural; the shifting beds of the distributaries, both natural and 
attificial, being gradually raised by the deposition of silt, a process 
which might have gradually involved the whole of Southern 
Seistan till the main body of the Helmand found an easier course 
northward. The present Hamun-i-Sabari, in its present relatively 
extended form, would be therefore quite modern—as shown, indeed, 
by the ruined city in its bed; though a comparatively small and 
intermittent pool may have previously been formed by the flood- 
waters of the Farah-Rud. It is also quite conceivable that, as it 
became increasingly difficult to keep open the irrigation channels 
in Southern Seistan, the Helmand may have heen artificially 
deflected northwards over the more easily watered northern tract. 
‘‘ So long as the delta spread chiefly over Southern Seistan, the 
Zitreh Lake must have been much more obviously and much more 
permanently than it is now the true termination of the Helmand 
system. The true relic of the large prehistoric lake alluded to by 
