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

Where Ryder crossed this river, lower down, he found it to be »a fair-sized affluent.»
Wood, who crossed it higher up, says: »On leaving Saka Dzong, our party kept
down the valley till we reached the Chata Tsangpo, which we found no difficulty in
crossing. The stream was at that time some 100 feet in width, with a depth of 2
feet, flowing in one channel, having just left a very deep narrow valley to emerge
into a plain of about 3 miles in width.»
On the 16th of November Ryder found the Tsangpo so completely frozen over,
that the caravan could pass on the ice. Of the plain W.N.W. of Tradum he says:
»This plain is full of small ponds lying among sand-dunes, and there was an unpleasant
tributary or two to cross, the water frozen at the edges for 4 or 5 yards.» Then
follows his description of the way up to Maryum-la which we know.
Ryder gives the very highest credit to the native explorers, notably Nain Sing
and A— K—.¹ And he adds: »In place of these rough maps, we have now an
accurate survey of the country traversed by the expedition.» In Rawling's opinion
the report compiled by Montgomerie is »somewhat meagre», though both Nain Sing's
and Montgomerie's merits were extremely great for their time.²
Rawling regards the Chi Chu as »a stream of considerable size rising in the
southern hills». There are hot springs in the valley. Raga-tsangpo and Chaktak-
tsangpo are not mentioned. Of Tsa-chu there are no particulars in the reports. But
Rawling tells us that the river near Tuksum »is a stream of considerable size, having
a width of 150 feet. Probably during the rainy season it overflows its banks, but even
in this state would be fordable in places. Now it formed a solid sheet of ice . . .».
The British missions to Lhasa and Shigatse have of course come into more
intimate contact with the Nyang-chu and Ki-chu than with any other part of the
Tsangpo system. At the time when Tashi Lama returned from India DAVID FRASER
visited Shigatse together with Captain FITZGERALD. On the outward journey they
took the ordinary road, but for the return a more westerly road over unknown
ground was chosen. Fraser gives some short descriptions of the Nyang-chu and
concerning its origin he says: »Out of the Kala Tso flows the Nyang Chu, the stream
which waters the Gyantse Valley and enters the Tsangpo . . .»³ Thus it is also
represented on the map in EDMUND CANDLER's book.⁴ Colonel WADDELL, however
says of Kala-tso: »This lake, which is said to have no outlet, is subject to some change
of level, rising in the rainy season for a quarter of a mile or so . . . The water,
although clear, was slightly brackish, and the shore covered by a white saline crust, which
supported the local report that the lake has no outlet — although in the maps of our
native surveyors, and in Bogle's account, it is made to flow into the Gyantsé river on its
east.»⁵ And again PERCEVAL LANDON says of the Nyang-chu: »This stream does not