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

326   THE UPPER TSANGPO TO CHÄROK.

nomads, and its small dunes bound by vegetation. From Camp 191, 4,608m. (15,114 feet) high, one sees to the north, through the opening of Tsagong-sang, a range with some strips of snow.

The left bank is perpendicular and nearly 2m. above the river; its soft sand and clay is constantly eaten and eroded by the current, so that blocks of earth are often heard falling into the water. The water is grey and muddy, the current slow.

This is only one branch of the Tsangpo, and just below the Camp it is split up into several smaller branches. The river is irregular, and undecided, and on the almost horizontal plain the waterways are meandering in all directions.

The first and principal branch was divided by a long narrow sandbank into two parts, of which the eastern one had the following dimensions: breadth -= 50m.;

maximum depth = 1.62m.; average depth = 1.306m,; average velocity    - 0.735m. a
second, and volume -- 48cub.m. a second. The western: breadth -- 30.2m. ; maximum depth =- o.96m. ; average depth -- 0.466m. ; average velocity ￿ 0.582m. a second, and volume = 8.i9cub.m. a second. That is to say 56. 19cub.m. in all, July 2nd. A little below the place the river could be forded with yaks.

On July 3rd we continued S.W. and soon came to a little branch with only o.32cub.m. The next branch was considerable and had the following dimensions: breadth -= 59.8m.; maximum depth = o.85m. ; average depth = 0.582m.; average velocity — 0.392m. a second, and volume 13.64cub.m. a second.

Further on in the same direction the plain becomes a little undulating; here a branch of only o.iocub.m. is passed. The next branch is great and muddy: breadth = 36.45m.; maximum depth = 1.26m.; average depth = o.873m. ; average

velocity    - o.7o3m. a second, and volume -- 22.37cub.m. a second.

The five branches, great and small together, therefore carried 92.6cub.m. a second.

If now the branches with clear water coming from the lake-like expansions near Dongbo had really contained water from the Näoo-tsangpo, I should have crossed this northern tributary on my way from Tuksum to Camp 191. In fact no tributary at all was crossed on this road. Ryder's map shows the confluence of the Näootsangpo straight south of Tuksum, and Nain Sing's map shows it S.W. of Tuksum. Both must be wrong for my Camp 191 lies due west of Tuksum on the bank of the Tsangpo and I had not crossed the great tributary. Therefore the junction of the Näoo-tsangpo with the Tsangpo must be situated above Camp 191.

The first branch, with 56cub.m.. includes the Näoo-tsangpo. Just below Camp 191 this branch divides into several branches. The greatest part of the 56cub.m. joins the Tsangpo; the rest forms the lake-like and very shallow expansions amongst the dunes, where the muddy water almost immediately becomes clear.

Continuing S.W. we pass between dunes partly bound by vegetation. Here is a little lake, Gävä-tso, surrounded by dunes, and full of small islands and wild geese. It is formed by the Gyang-chu or Kyang-chu, at the right bank of which