dropped from a higher level, and it was even then undoubtedly subsiding, the inflow having appreciably fallen off. At its south-western corner it is entered by two dry torrents, but it is not joined from the west by any stream worth speaking of. The next self-contained basin, one of very small area however, approaches quite close to it. This made the fourth lake we came across in this great latitudinal valley. Had we been traveling east, we should have had no great distance to go before we came to some of the head-streams of the Jang-tse-kiang, no great distance that is from the eastern end of the great salt lake. Had we proceeded along the same valley west from the lake at which we have now arrived, we should beyond doubt have found a chain of other lakes, arranged in precisely the same manner as the 23 lakes which I discovered in 1896 in the big latitudinal valley immediately south of the Arka-tagh, and in exactly the same manner as the lakes which Wellby and Malcolm discovered that same year in the next latitudinal valley to the south.
Leaving behind us the strip of barren alluvial ground at the western end of the lake, we travelled north-west over a gently rising surface. The ground was dry, and consisted of red sand and earth, with a thin sprinkling of grass. The watercourses were all treacherous, and here and there we came across a pool.
At Camp LVI (alt. 4828 m.) I took the temperature of the ground at different depths, and, with the temperature of the air at 9°, found that at a depth of 25 cm. the ground temperature was 8.4°, at 4o cm. 6.i°, at 55 cm. 4.9°, and at 7o cm. 4.3°.
September 24th. We now crossed the latitudinal valley diagonally, making for a gap in the northern range. On the whole it was in that direction that the surface rose, the ground consisting everywhere of red sand, perfectly firm and hard, though scored by a number of deeply excavated ravines, each with a level bottom. Down each of these there generally trickled a tiny rivulet, making its way
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