Our route gradually ascended, going north-west first, then swinging away to the north-east, until we attained an elevation of 17,350 feet on a flat basin covered with deep snow. So far we had gone on with no great trouble, but matters suddenly changed for the worse. Each coolie in the long silent row at the head of which I marched sank in snow up to his knees, often up to his waist. Their dark faces, wrapped tightly round in turbans, stood out in sharp contrast upon the white background. Some wore fur caps with ear-flaps. All had sheepskin coats and high boots. Many used snow-spectacles. Watching this silent procession of men with heavy loads upon their backs, struggling higher and higher with piteous panting, one could not help wondering anxiously as to how many of them would return to their own country alive. Moving cautiously to avoid treacherous crevasses, I made my way ahead to a spot six hundred feet higher, where I halted for a while on a rocky island fairly clear of snow. As coolie after coolie arrived panting hard, he dropped his load and sat quietly by the side of it. There was not a grumble, not a word of reproach for the hard work they were made to endure. Sleet was falling, and everything was wet and cold. From this point there was a steep pull before us. To the left we had a glacier, the face of which was a precipitous wall of ice about one hundred feet in height. Like the Mangshan glacier, it was in horizontal strata of beautifully clear ice with vertical stripes of dark green. The doctor and I went ahead. In our anxiety to reach the summit we mistook our bearings. With great fatigue we climbed an extremely steep incline. Here we were on a patch of troublesome loose stones, on which we struggled for over half an hour, until we reached the summit of the range, 18,750 feet--considerably higher than the pass itself. Most of the other men had proceeded by a dangerous way skirting the glacier. The wind from the north-east was piercing, and the cold intense. From this high point we obtained a beautiful bird's-eye view of the Tibetan plateau. Huge masses of snow covered the Tibetan side of the Himahlyas, as well as the lower range of mountains immediately in front of us, lying almost parallel to our range. Two thousand feet below, between these two ranges, flowed, in a wide barren valley, a river called the Darma Yankti. This river is the principal source of that great river which afterward takes the name of Sutlej. I was glad to be the first white man to visit the place where it has its birth. In the distance a flat plateau, rising some eight hundred feet above the river and resembling a gigantic railway embankment, could be seen for many miles. Far away to the north stood a chain of high blue mountains capped with snow--undoubtedly the Gangri chain with the Kelas peaks.