On the return journey in October I despatched Gujjar Singh from Gyangkar Nangpa to complete the remaining portions of the Sikkim revision-survey; at the same spot I picked up Lalbir Singh, who, after completing his survey of the Pharuk and Kharta areas, had crossed the Bhong Chu below Lungdoe and worked his way back via Tashirakar and Sar. Travelling via Kampa and Lachen Valley, we reached Darjeeling on October 16. Tracings of the new survey were hastily finished and sent to press, with the result that a complete preliminary 1/4-inch map in six colours was published before the last members of the Expedition had sailed for England. A 1/2-inch preliminary sketch-map of the environs of Mount Everest was also prepared by Major Wheeler at the same time for the use of the mountaineers in discussing the details of their next year's climb. The out-turn of work during the Expedition was as follows:-- 1/4-inch revision survey 4,000 square miles 1/4-inch original survey 12,000 square miles Detail photo-survey (environs of Mount Everest) 600 square miles The surveyors all worked splendidly under difficult and trying conditions. Major Wheeler had probably the hardest time of any member of the Expedition, and his success in achieving single-handed the mapping of 600 square miles of some of the most mountainous country in the world is sufficient proof of his determination and grit. It is difficult for those who have not actually had the experience to conceive the degree of mental and physical discomfort which results to the surveyor from prolonged camping at high altitudes during the monsoon, waiting for the fine day which never comes. Such was our fate for four months during the Expedition of 1921, yet on looking back one feels that the results were well worth while. The discomforts soon fade from recollection; the pleasures alone remain in one's memory, and there is not one of us but would gladly repeat our season's experiences, if so required. APPENDIX II THE PHOTOGRAPHIC SURVEY BY MAJOR E. O. WHEELER, M.C. I had purchased a set of photo-topographical surveying instruments of the Canadian pattern, on behalf of the Survey of India, while on leave in 1920. A trial of this method of surveying mountainous country was to be carried out in Garhwal in 1921; but when Survey of India officers were asked for to accompany the Mount Everest Expedition, I was detailed to carry out the trial there. Possibly a word of explanation of the method used may not be amiss.