[208] An inch and a half fell at Dorjiling during the same period.
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[[209]] 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° (air 43°), which gives an altitude of 16,754 feet.
[209] 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.
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° (max. 65°, min. 40·7°); extremes, 65/38°. The mean range (23·3°) was thus much greater than at Dorjiling, where it was only 8·9°. A thermometer, sunk three feet, varied only a few tenths from 57·6°. By twenty-five comparative observations with Calcutta, 1° Fahr. is the equivalent of every 362 feet of ascent; and twenty comparative observations with Dorjiling give 1° 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.[[210]] On the following day I descended to Lamteng, gathering a profusion of fine plants by the way.
[210] 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.
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;[[211]] the temperature of the water was 92° near the edges, where a water-insect (Notonecta) was swimming about.