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

less observed by Hindustani visitors, and from its intricate outline less easily comprehended
and described by them . . . . »

He then gives an excellent description of the western shore of Rakas-tal and
is right in saying the southern shore is so irregular, that it has to be surveyed in
detail if an idea of its form is to be gained. He passed the Chabgia Gumba without
seeing it. The name of the lake was found to be Cho Lagan, and it is not sacred.
At the shore he found marks of variation in the water-level to the extent of
a few feet. The water was quite pure and sweet, so the thick efflorescence of salt
he found on lately inundated, swampy ground, was supposed to arise from the soil.
Henry Strachey regarded the eventual connection between the two lakes and
the Satlej as an essential object of his journey. Regarding the effluence of Rakas-
tal, he arrived at the following conclusion: ¹

»There is no visible channel from the lake, and the only effluence is by filtration through
the porous soil of the intermediate ground, unless it be at times of extreme flood, when the
level of the lake may possibly rise high enough to overflow the margin at this corner. The
stream so formed flows westward, through an open valley; below Changchung it receives
the Sar-chu, a rivulet from the deep ravine immediately west of Kailás; the united stream then
takes the name of Lajandák, which is also an encamping ground on its banks about a day's
journey from Gángri . . . . . Moorcroft's statement regarding the Tirthapuri river (12th August),
agrees with this account of mine, though not with his own of the 15th, when he made the
Chugárh come from Rákas Tál. Hearsay's map makes the same mistake, and on the 13th
tdem, he describes two of the four tributary streams from the Gángri mountains large enough
to be bridged with Sángas, though he did not notice them on his way out to Mánasarowar,
1st and 2d August. The effluence of Rákas Tál probably contributes less to the Sutlej than
others of its numerous sources in the Gángri mountains, or the Indian Himálaya, for the
Bhotias say, that the stream at Lajandák, even after it has received the Sar-chu, is very incon-
siderable. It is a question that can be decided only by actual measurement perhaps, whether
the main source of the Sutlej be not in the Dárma-Yánkti, for the discharge of the Chúgarh
sometimes, though not constantly, exceeds that of the joint Tirthapúri and Misar river, as the
Bhotias testify, who are in the habit of fording both streams, close above their confluence at
Pálkia. The former is liable to great floods in the summer, the discharge of the latter being
more equable throughout the year.»

Thus Henry Strachey did not find any direct and superficial effluence from the
Rakas-tal. The only effluence was by filtration, although he does not say to what
depth this filtration goes. He finds it likely that at times of extreme flood there
may occur a superficial overflow as well. Moorcroft's mistake as to which branch
comes from the lake will be best understood from Hearsay's map (Pl. III). The
Tirtapuri Satlej cannot be said to be equable throughout the year. On the contrary,
the fluctuation in the volume of water is enormous. After heavy rains on the southern
slopes of the Gangri and surrounding mountains, the northern tributaries grow to
furious torrents. Supposing that rains chiefly touch the Himalayan side, the Darma-
yankti will get the most of it and grow to a river several times as big as the