In the preceding chapters I have tried to collect all that was known of the Transhimalaya in 1906. I have not dared to discuss the western and eastern continuation of the system beyond the frontiers of Tibet, as the material we possess is insufficient for any reliable conclusions, and under such conditions I regard it wiser to leave this problem to a future occasion. It only remains to me to give a general idea of my own results, and to begin with I have decided to describe every one of my eight crossings separately. I begin in the east and proceed westwards, disregarding the chronological order. After having described every separate transverse profile across the Transhimalaya, I will give a general résumé of the whole central part of the system so far as it is known at the present moment. Comparing my• results with the contents in the preceding historical chapters, the reader will be able to understand in how far I have contributed to our knowledge of the central parts of this gigantic and most interesting mountain system.
The first crossing begins from Camp i o8 on the Ngangtse-tso and ends a little beyond Camp 125 on the Tsangpo. The distance as the crow flies, is 216,6 kilometres, or 26o kilometres on my route. The height of the starting point on the lake is 4 694 m, the height beyond Camp 125, on the river, is 3 93o m. The culmination point of the system on this line is Sela-la with 5 506 m, which means a rise of 812 m from the lake to the highest point of the system, and a fall of 1 576 m from the same point to the Tsangpo. The distance from the Ngangtse-tso to Sela-la is 92,3 km, from Sela-la to the Tsangpo 127 km. Therefore the front-fall of the system towards the valley of the Tsangpo is much steeper than the back-fall towards the northern plateau land or Chang-tang. This fact will be more and more accentuated from west to east, so far as the Chang-tang, without outflow to the sea, stretches for beyond that limit the whole Tibetan mountain land begins to fall eastwards, in Kham and Szechuan. Westward, on the other hand, at the uppermost Tsangpo, there will be no difference at all between the plateau land and the Tsangpo, nay, we shall even find places where some of the lakes at the northern foot of the Transhimalaya will be found at a lower level than the corresponding parts of the valley of the Tsangpo. Or, in other words, the Tsangpo works its course deeper and deeper into the crust of the earth, whereas
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