国立情報学研究所 - ディジタル・シルクロード・プロジェクト
『東洋文庫所蔵』貴重書デジタルアーカイブ

least the satisfaction of feeling that we had done our uttermost for three days to achieve this. It was perhaps fortunate for us that our four boatmen were not

able to drag the two light canoes over the wide barrier where the bottom of the

lake was practically on the surface, or at any rate not more than 7 cm below it. This barrier probably formed the boundary between the fresh and the salt water.

The northern basin, in which we sought vainly for a channel of some depth, is

continually receiving fresh water from the Qum-darya, and the surplus runs over the barrier into the big southern basin, swollen into the shape of a balloon. This,

too, is in all probability very shallow. The greatest depth I ever sounded in Qaraqoshun was 4.5 m and the maximum depth of Lake Sogho-nor, into which two arms of the Edsen-gol delta run, was 4.12 m.

It is very unlikely that the depth of the new Lop-nor exceeds this figure. But that exasperating barrier prevented us from establishing this with certainty.

CHEN had walked all round the lake with HÖRNER, and knew that it was a good-sized salt pool, 13o km from north to south and 8o across at its widest point. Lake

Vänern, in Sweden, is about the same size, 140 by 80. But the whole northern

part of Lop-nor is a good deal narrower, and the total area of the lake is not half that of Vänern (5,55o sq. km). Vänern has, moreover, a river running through it,

so that it has fresh water and its size remains unchanged, or varies only to an insignificant degree. Lop-nor, on the other hand, is a terminal lake, and therefore has salt water and changes its size, as the inflow varies with the seasons. The size is also affected by evaporation, which is very marked in the hot, dry air of summer.

The volume of water in the Qum-darya was now diminishing every day, and the surface of Lop-nor was, accordingly, gradually sinking. If our plan had succeeded,

and we had been able to devote five days to the southern basin, the barrier might have been quite dry when we returned, and our communications with the northern fresh-water basin would in that case have been cut off.

When we found that in the existing conditions no further results could be obtained on the wandering lake, we steered back northwards to the little island where camp No. 83 was situated. Here we packed, loaded the canoes and embarked for the return voyage to Camp No. 82. There stood CHIA KUEI on a promontory, waving joyfully. He told us how delighted he had been when he had heard SADio's singing in the distance.

When we left that camp CHEN had set a bowl full of water out in the open air. In fifty-one hours 29 mm had evaporated. When the Qum-darya is falling daily

in summer, the level of Lop-nor must sink too, and the whole of the northern part

must be dry. Probably an arm of the Qum-darya winds across the exposed sediment of the lake-bottom throughout the summer; but it is possible that at the

height of summer this arm dries up before reaching the southern and deeper salt basin of the lake. If so, the latter is quite cut off, and it still remains to be seen

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