64 DISCOVERY OF HAN RECORDS CH. LV
improvised their rampart. Across an extensive desert area, bare of all resources, and of water in particular, it must have been a difficult task to construct a wall so solid as this, upon which even modern field artillery would make but little impression. The materials to which they had recourse, though of little apparent strength, were particularly well adapted to local conditions. I doubt whether any others within practicable reach could have stood better the stress of two thousand years and the constant onset of eroding forces.
I marched on for a mile and a half farther along and through low sand-dunes without coming upon any trace of the wall or sighting any more towers, though the view was open enough. Then regard for the animals, which needed water and grazing, obliged us to turn off northward in the direction of the river. We crossed in succession a belt of absolutely bare gravel ; a dry river bed with Toghraks still alive ; a zone where tamarisk growth was plentiful, but all dead ; and finally, after seven miles from the wall, arrived at the deep-cut bed of the Su-lo Ho fringed by a riverine jungle of scrub and wild poplars.
Where we camped for the night, the river, or the branch we could see, was over fifty yards broad and certainly far too deep for fording. Its muddy water, carrying big ice cakes, flowed with a velocity of about two yards per second. The night was not so bitterly cold as the one preceding, but the wind steadily increased in strength until the atmosphere in the morning assumed a regular Buran hue. The haze was sure to last for days, and a further search for wall and towers eastward would have little or no chance under these conditions. Besides, it
would have carried me to the town of An-hsi which I was bound to visit in any case later. The main object of my
search was already secured. I had discovered that the remains of the ancient wall actually continued eastwards of Tun-huang, as I conjectured from the first. I also had been able to prove the occupation of this Limes in the first century A.D.
So I decided, on April I st, to send the camp under the Surveyor's guidance back, to the conspicuous ridge
IIIF Color HighRes
