18 DR, HOOKER's MISSION TO INDIA. 
from Tonglo itself, separates Tonglo from the Darjeeling spur ; and we 
have as many ascents and descents to make, before reaching its base. From 
the sanatorium it appears one mass of forest, its sides furrowed by 
deep ravines, the top a short ridge of a lurid grey green colour. Like 
all the other Sikkim Sub-Himalaya hills, the outline: of Tonglo is 
tame, everywhere steep, but never precipitous. _ 
The great mountain, Sinchul, on which Darjeeling stands, first catches 
the S. E. or rainy winds, and so empties the clouds in part, before they 
reach Tonglo. In the mornings, Tonglo is very frequently visible from 
Darjeeling, and the heavens blue and clear from its top to the zenith ; 
whilst all the eastern hemisphere, up to the very summit of Darjeeling 
ridge, shows a dense mass of mist and rain. Except during the rains 
(from June to September inclusive, when the surrounding scenery is very 
seldom descried), the mornings are generally the finest part of the day, 
and the western horizon is invariably clear. At from eight to ten, a. m., 
the mists rise from the eastward, and gather round Darjeeling. At 
this time, only, small spotted clouds are collected on Tonglo, which, 
as the atmosphere becomes more and more loaded with moisture, dilate, 
unite, and envelope the whole mountain, whose humid flanks then 
receive a copious supply. By the same rule, the breaking up of the 
diurnal rain commences from the east, the mists rising first from the 
Bhootan hills ; and it is not till their vapours are dissipated that the 
then drier wind reaches Tonglo and dispels its shroud too. 
Hitherto, Tonglo had only been visited by the Surveyor-General, on 
the previous year (1847), who obtained, through Government, a reluc- 
tant assent from the Sikkim Rajah to his taking observations from its 
summit. No other European had trodden it. 
On May the 19th, we left Darjeeling at a little before noon, and 
descended a steep spur, from 7,000 to about 2,000 feet above the sea. 
The zones of arboreous vegetation through which we passed are 
similar, and similarly disposed, to those noticed during the descent 
to the Great Runjeet River. First, Chestnuts, Oak, and Magnolia ; 
. second, Tree-fern ; third, Palms (Calamus) ; fourthly, Plantain ; and then 
a host of tropical genera. As the native paths lead, of necessity, along 
the less wooded ridges, the transition is not recognized immediately ; 
but on looking into the gorges on either hand, the relative positions of 
these conspicuous plants, between the elevations of 6 and 7,000 feet (to 
which all ascend), is very obvious. Firing the forest is so easy an operation 
21 
