Every night that we spent in Tibet, we enjoyed a magnificent display of sunbeams converging to the east, and making a false sunset. I detailed this phenomenon when seen from the Kymore mountains, and I repeatedly saw it again in the Khasia, but never in the Sikkim Himalaya, whence I assume that it is most frequent in mountain plateaus. As the sun set, broad purple beams rose from a dark, low, leaden bank on the eastern horizon, and spreading up to the zenith, covered the intervening space: they lasted through the twilight, from fifteen to twenty minutes, fading gradually into the blackness of night. I looked in vain for the beautiful lancet beam of the zodiacal light; its position was obscured by Chomiomo. On the 18th of October we had another brilliant morning, after a cold night, the temperature having fallen to 4 degrees. I took the altitude of Yeumtso by carefully boiling two thermometers, and the result was 16,279 feet, the barometrical observations giving 16,808 feet. I removed a thermometer sunk three feet in the gravelly soil, which showed a temperature of 43 degrees,* [It had risen to 43.5 degrees during the previous day.] which is 12.7 degrees above the mean temperature of the two days we camped here. Our fires were made of dry yak droppings which soon burn out with a fierce flame, and much black smoke; they give a disagreeable taste to whatever is cooked with them. Having sent the coolies forward to Cholamoo lake, we re-ascended Bhomtso to verify my observations. As on the previous occasion a violent dry north-west wind blew, peeling the skin from our faces, loading the air with grains of sand, and rendering theodolite observations very uncertain; besides injuring all my instruments, and exposing them to great risk of breakage. The Tibetan Sepoys did not at all understand our ascending Bhomtso a second time; they ran after Campbell, who was ahead on a stout pony, girding up their long garments, bracing their matchlocks tight over their shoulders, and gasping for breath at every step, the long horns of their muskets bobbing up and down as they toiled amongst the rocks. When I reached the top I found Campbell seated behind a little stone wall which he had raised to keep off the violent wind, and the uncouth warriors in a circle round him, puzzled beyond measure at his admiration of the view. My instruments perplexed them extremely, and in crowding round me, they broke my azimuth compass. They left us to ourselves when the fire I made to boil the thermometers went out, the wind being intensely cold. I had given my barometer to one of Campbell's men to carry, who not coming up, the latter kindly went to search for him, and found him on the ground quite knocked up and stupified by the cold, and there, if left alone, he would have lain till overtaken by death.