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『東洋文庫所蔵』貴重書デジタルアーカイブ

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IoD

268 THE JESUIT CARTOGRAPHERS IN CHINA, AND D'ANVILLE'S MAP OF THE LAKES ETC.

still called Langchen-kabab 1 or the »mouth of the elephant), that is to say, the source of the Satlej. From a little lake at the foot of these mountains a river flows to the N.W. and empties itself in the I\Tanasarovar. This river is the Tage-tsangpo of my map, which comes from a glacier, Gang-lung, and not from a lake, though a moraine-lake may easily be situated in front of the snout of the glacier. A little farther north d'Anville has another nameless river, which is the same as the Samotsangpo of modern maps. This river also comes from a small lake which no longer exists. Close to the east of it we find L. Conghé which is Gunchu-tso of modern maps. The river flowing down from the valley of Pachung is also to be found on d'Anville's map, — without a name. But the mountain at its head, which I passed in 19o8, is on d'Anville's map entered under the name M. Patchon, although it has been placed north of Kailas instead of east. There are two lagunæ at the northern shore of L. Mapama, which also existed in 1907 and 1908. To the western lakelet two small rivers flow from the mountains east of Kailas, which is correct, and so is the little river which enters L. Lanken from the north. The general arrangement of the mountains is perfectly correct, proving that the Lamas have understood that the two lakes are situated between two great systems, the Himalaya and the Transhimalaya.

Farther, we find the channel going out of L. Mapama and entering L. Lanken and finally the Lanctchou R., or as now, Langchen-kamba, issuing from L. Lanken. D'Anville's map proves, that in 1717 the channel between the lakes was filled with water, and that the Satlej flowed from Rakas-tal. It also proves that the Samotsangpo did not issue from the Gunchu-tso, which would have been a physical impossibility, at least during the latter part of the post-glacial period.

On account of the original maps having been copied, the maps of d'Anville contain errors probably not to be found in the originals. Klaproth, and with him Ritter, regret that d'Anville did not keep to the detailed sheets of Tibet when joining them to his general map of that country which has therefore lost a good deal in exactness. The hydrography of our lakes as well as their surroundings are the same on both maps, but the latitude has been changed from 29h/2° on the special map to 311/z° on the general one, the correct situation being just between the two. 2

I Langchen-kamba is the name of the river.

2 In later chapters we shall often have to refer to this important map, as well as to the general map of Tibet, published by d'Anville in 1733. As the latter is more important in connection with the history of exploration in the country north of the Tsangpo, I have preferred to insert it in the part of this work which deals with Transhimalaya, Vol. III.

The reader will find that I have hitherto considered the world's knowledge of Tibet as a whole. In the following chapters I am going to separate the two lakes and the sources of the great rivers and deal with them separately, leaving the Transhimalaya and Kara-korum systems for special consideration. Exceptions to this rule will be found only occasionally.