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

Tibetan name of the river, which is Tamjan Khamba (horse's mouth). From Tamjan
there was a good view up the river for a considerable distance. The Tibetans all
agreed in saying that it was the main branch of the river.»

The river itself cannot be seen very high up, on account of the sinuosities
of the valley and the lower hills, but the Kubi-gangri is visible in the back-
ground.

Neither Ryder and Rawling nor I heard the name Tamjan at the confluence.
Ryder calls it Laktsang on his map. I heard only the name Shamsang. But all
three names may easily be used for different camping grounds on the plain, where
the rivers join. Montgomerie correctly observes that this place, Tamjan Tarjum,
reckoned from Maryum-la, is the first actually on the river. That is to say that only
here and not earlier, the Brahmaputra begins. Other rivers, belonging to its system,
have only been tributaries. Regarding the river, up the valley of which he could
see for a considerable distance, it is more than doubtful that it really was the Kubi-
tsangpo. I have marked the lower half of this river on my map with a dotted line,
because I saw only the confluence and its upper part. The Kubi-gangri is visible
W.S.W., as correctly marked on Nain Sing's map. The Kubi-tsangpo comes down
from the same direction. But on Nain Sing's map, »the main branch of the river
comes down in a straight line from W.S.W., which agrees well with the lower two
thirds of Chema-yundung, but not at all with the Kubi-tsangpo. That it is really
difficult to judge from where these intricate rivers come is easily visible from Ryder's
map, where, again, the directions of the valleys are quite different. Thus Nain Sing
has, at Tamjan, seen the confluence or the place where the united Chema-yundung
and Maryum-chu falls out into the Kubi-tsangpo. And he has believed that the
latter river came from and through the valley which is in fact occupied by Chema-
yundung. He reports ¹ that: »At Tamjan, on the 7th of June, the river was much
swollen, its current rapid and water turbid», which is true for the point where Kubi-
tsangpo comes out to the plain of Tamjan. And when the Tibetans said that this
river, Tamjan Khamba, was the main branch of the Tsangpo, they meant Kubi-
tsangpo, for the junction of the Chema-yundung is situated higher up. Therefore,
as compared with d'Anville's map, Nain Sing's map has not at all cleared up the
problem, but instead very much complicated the question of Brahmaputra's sources.
His view became, however, crystallized in Europe for some 40 years, and in the
meantime d'Anville's map became forgotten. And still d'Anville, or rather the Lama
surveyors, had made a mistake very similar to Nain Sing's. They had also con-
founded the source rivers. They divided the Chema-yundung into two different
rivers; the upper course was joint with the Kubi-tsangpo, and the lower with the
Maryum-chu. Nain Sing believed that the swollen, rapid and turbid river he saw at
Tamjan came from W.N.W., which is only the case with Chema-yundung.