In the corresponding region of the Mekong, however,
conditions are quite different. I followed this valley south-
wards almost continuously for 200 miles as the river flows
and was astonished at its barren aspect. Forest, or more
generally scrub, predominates in the rainy belt between
Tsu-kou and Hsiao- wei-hsi, but south of this the valley
becomes arid once more, and only grass partially conceals



264 The Land of Deep Corrosions

the scorched rocks. True, in the deep shady gullies the
vegetation becomes rich and varied with large trees, ferns,
orchids and creepers, even the wild banana being quite
common in latitude 26°, but these oases bear but a poor
relation to the whole valley, which can only be described
as barren and shrivelled up in appearance, terribly wearisome
to traverse day after day.
As to the valleys west of the Salween, I met in A-tun-
tsi two very interesting Chinese travellers who were able to
shed some light on the matter. One of them had been from
the Mekong to India with Prince Henri d'Orleans in 1895,
the other had only two years previously made a journey, for
political purposes one must suppose, from the Mekong as
far west as the 'Nmai-kha, some distance to the north of
Prince Henri's route. Both of them described the country
as covered with dense jungle, the summer rain as incessant,
and spoke lugubriously of mosquitos, leeches, tigers, and
other pests associated with such a climate. It is therefore
abundantly evident that the region west of the Salween gets
the full benefit of the south-west monsoon.
It is not till we get further north, where all three ridges
are suddenly elevated to a great altitude, that the effect of
the monsoon begins to wear off.
