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 UPPERMOST TRIBUTARIES TO THE TSANGPO.   235

M ontgomerie makes the following correct observation : i - Streams from glaciers

are always noted for having exceedingly dirty water, from the action of the glaciers on the rocks and earth in contact with them. Those who have travelled in glacier regions are hardly ever mistaken in deciding as to whether a stream comes from a glacier or not. The Pundit had been acquainted with glaciers all his life. His evidence as to the water would tend to show that the main branch of the river rose among glaciers, and he says that he saw the glaciers. On the other hand Montgomerie supposes that the northern tributaries do not come from glaciers, on account of the colour of their water. This is true as far as the Maryum-chu and some other northern tributaries are concerned. But such rivers as the Tsa-chutsangpo, Chaktak-tsangpo and others, are, at least to a considerable extent, fed by

glaciers. As to the main branch and source of the Brahmaputra one could never expect anything else than that it should be fed by unusually extensive and mighty glaciers. And here Nain Sing's observation and Montgomerie's conclusion were correct.

Where is now, according to Nain Sing's report, the source of the river? 2 Montgomerie does not leave us in the least doubt. It is already given in the title of the quoted article: latitude 3 I i;'2°, longitude 82°. This agrees almost exactly with the geographical situation of Tamlung-la, which indeed is the point farthest west in the whole system of the Brahmaputra. The brook going down from Tamlung-la belongs to the Chema-yundung, and thus we have obtained a new proof that the river which Nain Sing calls the main branch of the Brahmaputra is Chema-yundung and not Kubi-tsangpo, so much the more as the description in the text agrees with the map. Or in other words, Montgomerie places the source of the Brahmaputra at some 8 miles S.S.W. of the western end of Gunchu-tso. From this point, Tamlung-la, originates indeed a little tributary to the Chema-yundung, which is itself a tributary.

Under such conditions we are surprised to hear that Chu-Nago is called the first northern tributary and Chachu Sangpo (Tsa-chu) the second». Maryum-chu ought to be the first tributary if Chema-yundung were the main river. 3

It must be said that from Montgomerie's excellent and conscientious analysis of Nain Sing's report, it was not, however, easy to tell where the real source was situated. It seems that the co-ordinates given should be sufficient. But at another

Z Loc. cit. p. 213.

2 One could not help getting the impression that Nain Sing had really discovered the source of the Brahmaputra. The same dogma was afterwards found in many geographical handbooks and articles. Sir Clements Markham, for instance, says, that Nain Sing went »through the upper valley of the Brahmaputra, to the source of that river near the Månsarovar Lake.» The Geographical Magazine, Vol. II, 1875, p. 4.1.

3 It is an exaggeration to say: The river is nowhere fordable from its source to near Lhasa.'. For in its upper reaches it can be forded with ponies and yaks, though not without difficulty.