I i6o TO HAMI AND TURFAN [Chap. XXVIII
elabaration of these results will take time, and it is only in the proposed detailed report on my third expedition that I can hope to present them. To this publication I must accordingly leave the record of the observations concerning the geography and history of the Turfân region in general that I was able to make, and the discussion of the many interesting and complex questions to which they give rise. In the present place I shall limit myself strictly to a record of the modest exploratory work I found occasion to carry out at a couple of smaller sites, and to the information needed as regards the origin of certain antiques which were acquired elsewhere.
The hope of being able to study topographical and archaeological facts which might throw light on the subject of desiccation, as important in Turfân territory as in areas of ancient occupation within the Tarim Basin, induced me to start my tour at the south-eastern end of the basin. There Captain Roborovsky's map marked the ruins of Chong-hassitr, the ` Big Castle ', also locally known as Hassd[r ]-shahri, not far from the extreme eastern end of the marshy salt-lake bed which forms the deepest portion of the Turfân depression and gathers whatever is left of its surface drainage (see Map No. 59. c. 2). The ruins were declared by my Pichan informants to be situated on ground which was now wholly desert, and my archaeological predilection for the latter helped to decide me to make a start there. Our march on November 13 led down the barren narrow valley, where the waters of the Pichan tract disappear between bare clay ridges and drift-sand, and brought me to the flourishing oasis of Lukchun, watered mainly by the stream coming from Lamjin. Under the name of Liu-chung jß fi, it figures already in Han times as the seat of the ` Chang-chin' of the Western countries and as a chief foothold of Chinese power.3 Barometrical readings indicated for Lukchun an elevation of only some 5o feet above sea-level.
For a description of the interesting ground crossed next day on our march to the south-west I must refer to my Personal Narrative.4 Here it will suffice to mention that irrigation from newly constructed Karézes is steadily replacing the precarious cultivation formerly carried on with the water that the canals of Lukchun could bring down in favourable years to this outlying area. The immediate cause of this change, which is proceeding in most of the Turfan settlements, is certainly the increased pressure of population, following the re-establishment of peace and prosperity since the Chinese re-conquest. But since Karéz construction is admittedly a modern innovation in the Turfân region, not dating back further than the end of the eighteenth century at the earliest, we can account for the far larger population in ancient times, to which a variety of archaeological and historical indications point, only by assuming that the water-supply available from surface drainage in former periods was more plentiful than it now is.b
Clear evidence of the desiccation here implied, whatever its cause, period of commencement, or duration, was forthcoming on the approach to the site. At the farm of Bash-tam, some seven miles from the southern edge of continuous Lukchun cultivation, the last small patches of Karéz-irrigated land were left behind. Beyond we passed fields long ago abandoned and overrun by thorny scrub of the desert, and then crossed a shallow bed in which the water of the Lukchun canals, when left unused in the winter, endeavours to make its way down to the terminal lake-bed. On account of evaporation and absorption in the soil, no water could now ever reach so far down during the spring, when it is most needed in the oasis, or during the terrible heat of the Turfân summer, unless, perhaps, at the time of quite exceptional rain-floods from the distant mountains. To the south of this temporary overflow-bed there stretched a wide sandy plain with plentiful thorny scrub and small tamarisks growing amidst rudimentary dunes. Wherever the ground was left clear of drift-