had no means of judging, but the rapid slope of the river-bed is
mainly due to this, and to old moraines at the mouth of the valley
below. I have seen few finer sights than the fall of these stupendous
blocks into the furious torrent, along which they are carried amid
feathery foam for many yards before settling to rest.

Across the Thlonok to the southwards, rose the magnificent mountain
of Tukcham, but I only once caught a glimpse of its summit, which
even then clouded over before I could get my instruments adjusted for
ascertaining its height. Its top is a sharp cone, surrounded by rocky
shoulders, that rise from a mass of snow. Its eastern slope of 8000
feet is very rapid (about 38 degrees) from its base at the Zemu river
to its summit.

Glaciers in the north-west Himalaya descend to 11,000 feet; but I
could not discover any in these valleys even so low as 14,000 feet,
though at this season extensive snowbeds remain unmelted at but
little above 10,000 feet. The foot of the stupendous glacier filling
the broad head of the Thlonok is certainly not below 14,000 feet;
though being continuous with the perpetual snow (or neve) of the
summit of Kinchinjunga, it must have 14,000 feet of ice, in
perpendicular height, to urge it forwards.

All my attempts to advance up the Zemu were fruitlesss and a snow
bridge by which I had hoped to cross to the opposite bank was carried
away by the daily swelling river, while the continued bad weather
prevented any excursions for days together. Botany was my only
resource, and as vegetation was advancing rapidly under the influence
of the southerly winds, I had a rich harvest: for though _Compositae,
Pedicularis,_ and a few more of the finer Himalayan plants flower