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

THE PRINCIPAL TRIBUTARY TO THE TSANGPO.

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the boatmen I spoke to asserted there was less danger in summer when banks and rocks in the bed are avoided. Now there were no boats at Chaga, and as the bridge could not be trusted, passengers to Pindsoling had to take the road over Latse. When I asked from where the Damchok-kamba, as they called the river, came, they answered : from the Gangri, six months to the west. From Pindsoling to Latse and further west Ryder followed the southern bank of the Tsangpo.

To the S.7 I °E. the valley offers a picturesque perspective, with Mount Chaong-la in the background. S. 2 2°E. is Mount Nagya; on the ridge originating from Nagya is the dsong of Pindsoling, S.4°W. from Chaga. Beyond this ridge, or S.4°E., is a peak Gunje-dubuk; to the right of it is a pass Tarkung-la; south of the pass is a region Chuarung, inhabited by nomads. Between Tarkung-la and Pindsoling is said to be a valley called Chonang with a monastery Chonang-gompa; S.2 8°W. is a peak Ngombo-chong. Just above Chaga the Tsangpo goes through a narrow passage, Chibuk, where there is no room for the road to Dok-chu and Raga-tsangpo. The road therefore has to cross a little pass Chikchung-chang in a ridge from the north; a gorge in the N.W. leads to the pass.

Grey granite prevails. At Chaga on the northern bank of the Tsangpo there are innumerable granite boulders of all sizes, generally about one meter across; the ground is sandy. A curious sand-dune, called Chiri is formed on the eastern, or lee-side, of the ridge W.S.W., a work of the west-wind; it begins just below the crest and describes a regular curve down to near the river. It is of course stationary, constantly fed by the west-wind, and again diminished by the same wind. It is as a station for the drifting sand on its way down the valley, and its form, size and situation is a result of eternal physical laws. Several other mountain sides in the neighbourhood are covered by dunes and look striped like tiger-skins. Both at Pusum and Chaga I noticed in the evening and night a very strong and hard wind blowing down in the valley like cascades from above.

From Chaga our road goes up the dry narrow gorge to Chikchung-chang, on the pass of which a hla is built above the precipice of the valley. The road to Latse follows immediately along the river, some I om. above its level, and at the side of steep mountains with a peak called Doombi-tang and visible to the S.67°W. from the pass. A peak to the 5.8 I °W. is called Karong, another to the N.83°W. Damboo-richen. The road down from the pass is very steep and unpleasant. The level bottom of the valley may be one mile broad, and is covered with gravel

and sand.

At the foot of Doombi-tang is the important point where the Tsangpo comes from S.W. between steep picturesque rocks, and joins the Dok-chu, coming from the west, and called Raga-tsangpo above the junction with the Mü-chu. The height is 4,013m. (13,163 feet). On April 6th I measured the volume of both rivers.

The Dok-chu was divided into two branches. In the greatest of these the depth was measured at II points and gave an average of o.78m., the maximum depth

39-131387 II.