On August 19 Heron suddenly arrived back after a very interesting trip, during which he had explored all the mountains North of Tingri and Shekar Dzong up to the Brahmaputra watershed. He had had very bad weather all the time. Every night there had been heavy thunderstorms and practically all the bad weather had come from the North. The whole country was under water, and it was very difficult to get about. Some of the rivers that we had crossed earlier in the season were now a mile or more wide. On the following day Bullock and Mallory returned to Kharta after having explored the Upper Kharta Valley. They thought that they had found a possible way up Mount Everest from this valley, but at present the weather was too bad for them to carry on with their reconnaissance, and they had come down for a fortnight's rest, hoping that the Monsoon would be over by the beginning of September and that they would then be able to make a proper attack on the mountain. As Mallory and Bullock were likely to be at Kharta for some time, Wollaston and I seized this opportunity to visit the lower valley of the Kama-chu. Therefore, on August 23, with eleven of our own coolies and several Tibetan coolies, we climbed the Samchung Pass (15,000 feet), and then descended into the valley of the fourteen lakes, and after crossing the Chog La camped on the far side of the pass near a dark green and sacred lake called Ruddamlamtso. On the way we saw a new species of black rat in the moraine of a glacier; but Wollaston's servant, who had the collecting gun with him, was unfortunately far behind; he was always rather fond of drink and loth to leave the villages. The weather was cloudy, and there were no views from the top of either pass. The march was a strenuous one, taking the coolies thirteen hours to cover the whole distance, and they did not arrive till after dark. The Ruddamlamtso, the lake by which we were camped, had wonderfully clear water; I could see every stone at a depth of 20 feet, and it was evidently very deep. It is looked upon as a sacred lake, and to it people make yearly pilgrimages, walking round it burning incense and throwing spices into its waters.