I spent a week at Tungu most pleasantly, ascending the neighbouring mountains, and mixing with the people, whom I found uniformly kind, frank, and extremely hospitable; sending their children after me to invite me to stop at their tents, smoke, and drink tea; often refusing any remuneration, and giving my attendants curds and yak-flesh. If on foot, I was entreated to take a pony; and when tired I never scrupled to catch one, twist a yak-hair rope over its jaw as a bridle, and throwing a goat-hair cloth upon its back (if no saddle were at hand), ride away whither I would. Next morning a boy would be sent for the steed, perhaps bringing an invitation to come and take it again. So I became fond of brick-tea boiled with butter, salt, and soda, and expert in the Tartar saddle; riding about perched on the shoulders of a rough pony, with my feet nearly on a level with my pockets, and my knees almost meeting in front.
On the 28th of July much snow fell on the hills around, as low as 14,000 feet, and half an inch of rain at Tungu;* [An inch and a half fell at Dorjiling during the same period.] the former soon melted, and I made an excursion to Chomiomo on the following day, hoping to reach the lower line of perpetual snow. Ascending the valley of the Chomiochoo, I struck north up a steep slope, that ended in a spur of vast tabular masses of quartz and felspar, piled like slabs in a stone quarry, dipping south-west 5 degrees to 10 degrees, and striking north-west. These resulted from the decomposition of gneiss, from which the layers of mica bad been washed away, when the rain and frost splitting up the fragments, the dislocation is continued to a great depth into the substance of the rock.
Large silky cushions of a forget-me-not grew amongst the rocks, spangled with beautiful blue flowers, and looking like turquoises set in silver: the Delphininin glaciale* [This new species has been described for the "Flora Indica" of Dr. Thomson and myself: it is a remarkable plant, very closely resembling, and as it were representing, the D. Brunonianum of the western Himalaya. The latter plant smells powerfully of musk, but not so disagreeably as this does.] was also abundant, exhaling a rank smell of musk. It indicates a very great elevation in Sikkim, and on my ascent far above it, therefore, I was not surprised to find water boil at 182.6 degrees (air 43 degrees), which gives an altitude of 16,754 feet.
A dense fog, with sleet, shut out all view; and I did not know in what direction to proceed higher, beyond the top of the sharp, stony ridge I had attained. Here there was no perpetual snow, which is to be accounted for by the nature of the surface facilitating its removal, the edges of the rocks which project through the snow, becoming heated, and draining off the water as it melts.
During my stay at Tungu, from the 23rd to the 30th of July, no day passed without much deposition of moisture, but generally in so light a form that throughout the whole time but one inch was registered in the rain-gauge; during the same time four inches and a half of rain fell at Dorjiling, and three inches and a half at Calcutta. The mean temperature was 50 degrees (max. 65 degrees, min. 40.7 degrees); extremes, 65/38 degrees. The mean range (23.3 degrees) was thus much greater than at Dorjiling, where it was only 8.9 degrees. A thermometer, sunk three feet, varied only a few tenths from 57.6 degrees. By twenty-five comparative observations with Calcutta, 1 degree Fahr. is the equivalent of every 362 feet of ascent; and twenty comparative observations with Dorjiling give 1 degree for every 340 feet. The barometer rose and fell at the same hours as at lower elevations; the tide amounting to 0.060 inch, between 9.50 a.m. and 4 p.m.
I left Tungu on the 30th of July, and spent that night at Tallum; where a large party of men had just arrived, with loads of madder, rice, canes, bamboos, planks, etc., to be conveyed to Tibet on yaks and ponies.* [About 300 loads of timber, each of six planks, are said to be taken across the Kongra Lama pass annually; and about 250 of rice, besides canes, madder, bamboos, cottons, cloths, and Symplocos leaves for dyeing. This is, no doubt, a considerably exaggerated statement, and may refer to both the Kongra Lama and Donkia passes.] On the following day I descended to Lamteng, gathering a profusion of fine plants by the way.
The flat on which I had encamped at this place in May and June, being now a marsh, I took up my abode for two days in one of the houses, and paid the usual penalty of communication with these filthy people; for which my only effectual remedy was boiling all my garments and bedding. Yet the house was high, airy, and light; the walls composed of bamboo, lath, and plaster.
Tropical Cicadas ascend to the pine-woods above Lamteng in this month, and chirp shrilly in the heat of the day; and glow-worms fly about at night. The common Bengal and Java toad, Bufo scabra, abounded in the marshes, a remarkable instance of wide geographical distribution, for a Batrachian which is common at the level of the sea under the tropics.
On the 3rd of August I descended to Choongtam, which I reached on the 5th. The lakes on the Chateng flat (alt. 8,750 feet) were very full, and contained many English water-plants;* [Sparganium ramosum, Eleocharis palustris, Scirpus triqueter, and Callitriche verna? Some very tropical genera ascend thus high; as Paspalum amongst grasses, and Scleria, a kind of sedge.] the temperature of the water was 92 degrees near the edges, where a water-insect (Notonecta) was swimming about.
Below this I passed an extensive stalactitic deposit of lime, and a second occurred lower down, on the opposite side of the valley. The apparently total absence of limestone rocks in any part of Sikkim (for which I made careful search), renders these deposits, which are far from unfrequent, very curious. Can the limestone, which appears in Tibet, underlie the gneiss of Sikkim? We cannot venture to assume that these lime-charged streams, which in Sikkim burst from the steep flanks of narrow mountain spurs, at elevations between 1000 and 7000 feet, have any very remote or deep origin. If the limestone be not below the gneiss, it must either occur intercalated with it, or be the remains of a formation now all but denuded in Sikkim.