ICE AND SOUNDINGS IN THE TSO-NGOMBO.
water, and in its lowest course the valley of the Tsanger-schar would push out a bay. At the period we are contemplating the Tso-ngombo will have been as much as 85 m. deep, and possibly deeper. If now we assume, that the constant shrinkage, which is revealed by the strand-ramparts, continues also in the future, then the stream, in spite of its constantly decreasing volume, will go on excavating its bed deeper in the isthmus between the two lakes. In the eastern part of the Tsongombo we have already noticed several separate basins. Numerous others of a like character would gradually make their appearance in the large lake. Finally they also would disappear, the last of them being a salt lake, which would receive water from the Tsanger-schar when the latter was in flood, the Tsanger-schar
Fig. 216. TIBETAN ENCAMPMENT NORTH OF CAMP CXLIV.
itself making a single continuous river flowing down the valley. After I have described our journey along the northern shore of the Panggong-tso, I propose to return again for a further brief consideration of this interesting and fascinating pair of lakes.
During the three days that we spent at Camp CXLIV the wind blew hard from the west in a series of intermittent gales, bringing with it such vast clouds. of dust and sand that at times it made the day as dim as twilight. The great quantities of material which are in this way carried into the western part of the Tso-ngombo from the isthmus and the adjacent mountains help in some respects to render its basin shallow. These gales retarded the freezing of the lake, and so long as we remained there, the western part of the lake remained open. During temporary lulls that occurred on the 7th and 8th December we seized the opportunity to take soundings in the western part of the Tso-ngombo.
The series of soundings which I then proceeded to take were made along a zigzag line in the following way: from the outfall (A) of the river S. 45° E. to a
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