The expedition made its way almost due west behind the main chain of the Himalaya, until one evening its members saw, almost due south of them, a beautiful peak which was apparently very high. The natives called it Chomo-Uri, which means the "Goddess of the Turquoise Peak," and from observations next morning it was clear that it was Everest. They passed some wonderful monasteries perching on the face of perpendicular crags, and eventually, on 19th June, they reached Tingri Dzong, after a month's travelling from Darjeeling. This was the spot they had decided upon for their base camp. The obvious route to Everest seemed to be by way of the Rongbuk valley, where the great Rongbuk Glacier flowed from its northern face. There, accordingly, the two climbers, Mr. Mallory and Mr. Bullock, established themselves. The preliminary reconnaissance, however, proved to be a somewhat intricate matter. It was soon plain that there were no easy approaches from the west, so Colonel Howard-Bury moved his headquarters to Kharta, on the east side, close to the Arun. That river, which there is about one hundred yards wide, a little farther down enters great gorges, in which, within a course of twenty miles, it drops from 12,000 feet to 7,500 feet, or over 200 feet in a mile--a far more wonderful spectacle than anything on the Brahmaputra. On 2nd August, Mr. Mallory and Mr. Bullock started their exploration of the eastern approaches to the mountain. This was no easy business, for the valleys were separated by ridges, the lowest point of which was higher than any mountain in Europe, and every route had to be explored personally, for no information could be had from the natives. The two main valleys running down on the east side of Everest are the Kharta and, farther south, the Kama. The latter valley was first explored, and it was found that it ended under the precipitous eastern face of the mountain, and that there was no way from it of reaching the North-East ridge. It was a marvellous valley for scenery, but for mountaineering impracticable. A move was accordingly made to the Kharta valley to the north. Mr. Mallory and Mr. Bullock proceeded up this till they reached the glacier of the Kharta River, and at last found a valley which seemed to lead them straight to the North-East ridge. It was now, however, early August, the monsoon was blowing, and everywhere there was deep, soft, fresh snow. They returned accordingly to the camp at Kharta to wait till weather conditions became better.