A Winter Journey amongst the Lutzu 189 
like frosted silver, winding between its high spurs. Towards 
morning the valley filled with dense mist to a depth of one 
or two hundred feet, and when we woke up we saw below 
us only a monstrous white river of cloud washing round 
the cliffs. This was not dispersed till the sun topped the 
high range we had just crossed, when it began to seethe and 
steam up, dewing the spiders’ webs on the trees as it passed 
till they looked like gossamer. The same thing happened 
on the following morning, and I am inclined to attribute 
the phenomenon to the probable fact that the water of 
the Salween is at this time colder than the rocks of the 
valley, protected as they are from excessive radiation by 
vegetation, so that the air in contact with the river is 
gradually cooled down below the dew-point and precipitates 
its moisture in the form of a dense bank of cloud. I saw 
no such thing take place in the Mekong valley, where the 
rocks are largely devoid of vegetation and the radiation 
correspondingly more rapid; moreover the air is much drier 
there, since the high Mekong-Salween divide intervenes to 
desiccate it. 
Cho-ton consists of about a score of huts built on a 
bluff a few hundred feet above the river; Cho-la, where we 
had stayed before, was visible on the flat river terrace at 
our feet, scarcely half a mile down the valley, and thither 
we proceeded after breakfast. 
It was a glorious day, and I decided to rest here before 
starting on the difficult journey over the Sie-la; for after 
the cold of the mountains, what could be more delightful 
than to bask in the sunshine for a day! In the gullies 
several beautiful orchids were in flower, fields of buckwheat 
and millet covered the plain, and the women were sitting 
outside their huts weaving hemp cloth. Later I went down 
to the bed of the river, where the water was beautifully clear 
and green. Here the barometer read 24°96 ins. 
Now Cho-la on the Salween, Tsu-kou on the Mekong 
and Pang-tsi-la on the Yang-tze are practically in the same 
latitude. In the river bed at Pang-tsi-la in September the 
barometer read 22°25 ins., and in the bed of the Mekong 
at Tsu-kou in November, 23°96 ins. These readings, of 
course, do not give the absolute altitudes of the river beds, 
but for comparative purposes they are I believe fairly 
