Scientific Results of a Journey in Central Asia, 1899-1902 : vol.1 / 42 ページ（白黒高解像度画像）

0042	Scientific Results of a Journey in Central Asia, 1899-1902 : vol.1
1899-1902年の中央アジア旅行における科学的成果 : vol.1

0042

Scientific Results of a Journey in Central Asia, 1899-1902 : vol.1

1899-1902年の中央アジア旅行における科学的成果 : vol.1

20 THE TARIM RIVER.

forest, undermines the trees nearest to

the edge, and so causes them to topple

down into the water and be swept away.

Every landslide in such places carries

with it masses of intertwined roots. It

is at these sharp bends that the erosive

power of the stream is most conspi-

cuously displayed, not only upon the

extreme face of the elbow itself, but

also in the river-bed at its foot. The

sharper the elbow, that is to say the

greater the change of direction in the

river's course, the greater becomes the

conversion of the power which is represented .by the movement of the water into another species of energy, namely the erosion of the concave bank and of the river-bottom immediately contiguous to it. The sharper the bend, therefore, the greater becomes the depth of the river adjacent to it. On the opposite or convex side the work of depositing alluvium proceeds simultaneously at a corresponding rate. And in a country like East Turkestan, where the general inclination is so slight, and the surface consists of such soft and pliant materials, there exists practically no check upon the sinuous tendencies of the current. At the same time there is a period of maturity naturally prescribed for each bend; for if each loop or elbow is regarded as a peninsula, then its root, or connecting isthmus, becomes assailed from both sides at once; the opposite margins gradually approach one another, until there is only a narrow neck or mere strip of land left between them, and finally this becomes so weak that it is unable to resist the next flood, and is consequently cut in two. In this way what was originally a loop of the river becomes

Fig. IS. DRIFT OF THE FERRY-BOAT UPON
THE JARKENT-DARJA.

Fig. I9. ORDINARY FERRY-BOAT FOR PASSING OVER CARAVANS.

[Photo] Fig. 18	ヤルカンド・ダリヤでのフェリー・ボートの漂流。DRIFT OF THE FERRY-BOAT UPON THE JARKENT-DARJA.
[Photo] Fig. 19	キャラバンを輸送するための通常のフェリー・ボート。ORDINARY FERRY-BOAT FOR PASSING OVER CARAVANS.

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
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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

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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