Routes from Choongtam to Tibet frontier -- Choice of that by the Lachen river -- Arrival of Supplies -- Departure -- Features of the valley -- Eatable _Polygonum_ -- Tumlong -- Cross Taktoong river -- Pines, larches, and other trees -- Chateng pool -- Water-plants and insects -- Tukcham mountain -- Lamteng village -- Inhabitants -- Alpine monkey -- Botany of temperate Himalaya -- European and American fauna -- Japanese and Malayan genera -- Superstitious objections to shooting -- Customs of people -- Rain -- Run short of provisions -- Altered position of Tibet frontier -- Zemu Samdong -- Imposition -- Vegetation -- Uses of pines -- Ascent to Thlonok river -- Balanophora wood for making cups -- Snow-beds -- Eatable mushrooms and _Smilacina_ -- Asarabacca -- View of Kinchinjunga -- Arum-roots, preparation of for food -- Liklo mountain -- Bebaviour of my party -- Bridge constructed over Zemu -- Cross river -- Alarm of my party -- Camp on Zemu river. From this place there were two routes to Tibet, each of about six days' journey. One lay to the north-west up the Lachen valley to the Kongra Lama pass, the other to the east up the Lachoong to the Donkia pass. The latter river has its source in small lakes in Sikkim, south of the Donkia mountain, a shoulder of which the pass crosses, commanding a magnificent view into Tibet. The Lachen, on the other hand (the principal source of the Teesta), rises beyond Sikkim in the Cholamoo lakes. The frontier at Kongra Lama was described to me as being a political, and not a natural boundary, marked out by cairns, standing on a plain, and crossing the Lachen river. To both Donkia and Kongra Lama I had every right to go, and was determined, if possible, to reach them, in spite of Meepo's ignorance, our guide's endeavours to frighten my party and mislead myself, and the country people's dread of incurring the Dewan's displeasure. The Lachen valley being pronounced impracticable in the height of the rains, a month later, it behoved me to attempt it first, and it possessed the attraction of leading to a frontier described as far to the northward of the snowy Himalaya, on a lofty plateau, whose plants and animals were different from anything I had previously seen. After a week the coolies arrived with supplies: they had been delayed by the state of the paths, and had consequently consumed a great part of my stock, reducing it to eight days' allowance. I therefore divided my party, leaving the greater number at Choongtam, with a small tent, and instructions to forward all food to me as it arrived. I started with about fifteen attendants, on the 25th of May, for Lamteng, three marches up the Lachen.