A gently sloping saddle, bare of snow, which succeeds the glacier, forms the top of the Tunkra pass; it unites two snowy mountains, and opens on the great valley of the Machoo, which flows in a part of Tibet between Sikkim and Bhotan; its height is 16,083 feet above the sea by barometer, and 16,137 feet by boiling-point. Nothing can be more different than the two slopes of this pass; that by which I had come presented a gentle snowy acclivity, bounded by precipitous mountains; while that which opened before me was a steep, rocky, broad, grassy valley, where not a particle of snow was to be seen, and yaks were feeding near a small lake not 1000 feet down. Nor were snowy mountains visible anywhere in this direction, except far to the south-east, in Bhotan. This remarkable difference of climate is due to the southerly wind which ascends the Tibetan or Machoo valley being drained by intervening mountains before reaching this pass, whilst the Sikkim current brings abundant vapours up the Teesta and Lachoong valleys. Chumulari lies to the E.N.E. of the Tunkra pass, and is only twenty-six miles distant, but not seen; Phari is two marches off, in an easterly direction, and Choombi one to the south-east. Choombi is the general name given to a large Tibetan province that embraces the head of the Machoo river, and includes Phari, Eusa, Choombi, and about thirteen other villages, corresponding to as many districts, that contain from under a dozen to 300 houses each, varying with the season and state of trade. The latter is considerable, Phari being, next to Dorjiling, the greatest Tibetan, Bhotan, Sikkim, and Indian entrepot along the whole Himalaya east of Nepal. The general form of Choombi valley is triangular, the broader end northwards: it is bounded by the Chola range on the west from Donkia to Gipmoochi, and by the Kamphee or Chakoong range to the east; which is, I believe, continuous with Chumulari. These meridional ranges approximate to the southward, so as to form a natural boundary to Choombi. The Machoo river, rising from Chumulari, flows through the Choombi district, and enters Bhotan at a large mart called Rinchingoong, whence it flows to the plains of India, where it is called at Couch-Behar, the Torsha, or, as some say, the Godadda, and falls into the Burrampooter. The Choombi district is elevated, for the only cultivation is a summer or alpine one, neither rice, maize, nor millet being grown there: it is also dry, for the great height of the Bhotan mountains and the form of the Machou valley cut off the rains, and there is no dense forest. It is very mountainous, all carriage being on men's and yaks' backs, and is populous for this part of the country, the inhabitants being estimated at 3000, in the trading season, when many families from Tibet and Bhotan erect booths at Phari.