After completing the necessary preliminaries with Colonel Bury, I myself left Darjeeling on May 13, intending to rejoin the remainder of the Expedition in Sikkim. Continuous rain, however, rendered the latter task impossible; the Sikkim roads were, moreover, blocked in several places by severe landslips, so that I was only with difficulty able to reach Kampa by the 28th. It transpired, however, that there was no cause for hurry, since the main body of the Expedition, travelling via the Chumbi Valley, had encountered greater difficulties than mine, and did not arrive at Kampa until June 5. While awaiting their arrival, I filled in the time by occupying and re-observing from Colonel Ryder's old triangulation stations of 1903, overlooking the Kampa Plain. I had received no news whatever of the Expedition or of the outside world since leaving Darjeeling three-and-a-half weeks previously. Consequently the death of my old friend Dr. Kellas on the very day of their arrival at Kampa came to me as a very severe shock. The Sikkim revision-survey having been so much hampered by bad weather, I decided to take only two of the three surveyors with the Expedition into Tibet, leaving Surveyor Turabaz Khan to complete the comparatively dry areas of Northern Sikkim before the arrival of the monsoon. This he succeeded in doing at the cost of considerable personal discomfort, returning to Darjeeling in July. It was not until we reached the summit of the Tinki Pass on June 11 that we found ourselves for the first time looking into unsurveyed country. From here onwards as far as Tingri the survey was kept up by Lalbir Singh, whose unflagging energy alone enabled him to keep pace with the long marches of the Expedition. Each morning he was away with his plane-table and squad of coolies long before our breakfast was served, seldom reaching camp before nightfall. The gathering clouds and other ominous signs of a rapidly approaching monsoon, however, forbade any respite. On arrival at Tingri, after spending a week in fruitless efforts to observe the triangulated peaks of the main Himalayan Range through the dense monsoon clouds which were daily piling up more and more thickly from the South, I departed on June 26 with Surveyor Gujjar Singh on a short trip to explore and map the upper valley of the Bhong Chu.