a third Journey to the Yang-tze 171 
It was a glorious night, the sky powdered with myriads 
of stars, but the cold was intense. The dark figures of the 
men curled up round the leaping fire looked ghostly in that 
lonely mountain valley. I could just hear the murmur of 
the torrent, and occasionally the tinkle of the ponies’ bells 
as they hobbled about looking for grass; otherwise the 
night was extraordinarily still, and I was just dropping off 
to sleep when I heard the Tibetans running about and 
shouting ; apparently the animals had strayed or another 
party had joined us. Then the canvas of the tent began to 
buckle noisily as it froze, and taking it all round I slept 
badly, though with heaps of woollen clothes on I kept 
warm beneath my five blankets. 
Next morning in brilliant weather we started early for 
the pass. The frost had been severe, the path was like 
iron, and there was much more ice about. Scattered along 
the stream-side were dwarf willow and occasional clumps 
of a large-leafed Seneczo which ascends right to the furthest 
limit of plants. 
It is remarkable that while trees extend to higher alti- 
tudes on the valley sides than on the valley floor, shrubs 
on the other hand extend to higher altitudes on the valley 
floor than on the valley sides. The reason is doubtless to 
be found in the fact that, towards the summit of the water- 
shed, wind and water are both concentrated in the valley 
bottom, the former being inimical to trees, while at higher 
elevations the latter is essential to the shrub vegetation. 
Thus, towards their limit, trees are driven to occupy sheltered 
places on the mountain slopes, while towards the limit of 
shrubs, the dwarf vegetation which is able to withstand the 
wind is driven to occupy the valley floor, rhododendron 
giving place to willow. 
Just above the lake I had found on the previous day 
we came into the snow, which grew rapidly deeper, but 
happily the party which had joined us on the previous 
night and gone on ahead had stamped a trail, otherwise we 
should have found it desperately hard work. 
The last few hundred feet were up a zigzag path, the 
precipitous rock wall rising abruptly above us to a small 
notch in the ridge, which was the Riin-tsi-la. The snow 
here was very deep, and nowhere on the exposed rock was 
