The most important scientific work of the first year's expedition should have been the study of the physiological effects of high altitude that Dr. Kellas had undertaken, with the support of Professor Haldane, F.R.S., and of the Oxygen Research Committee of the Department of Scientific and Industrial Research. In his work on Kamet in 1920, Dr. Kellas had tried, and provisionally decided against, the use of oxygen compressed in cylinders: but he laboured under the grave disadvantage that the light cylinders he hoped to obtain had been, after his departure for India, pronounced unsafe; and the cylinders sent out were clearly too heavy for effective use in climbing. Dr. Kellas had therefore fallen back on the use of oxygen prepared from the reaction between water and oxylith in an apparatus which included a kind of gas mask. He was prepared also to make several difficult researches into the physiological processes of adaptation to low oxygen pressure; and some delicate apparatus was prepared and sent out to him by the Oxygen Research Committee. Unhappily these interesting and important enquiries came to nought, for there was no one competent to carry them on after his lamented death at Kampa Dzong; and the Expedition of 1922 was thereby deprived of much information that should have been at its disposal in studying the use of oxygen for the grand assault. The scientific equipment for which the Mount Everest Committee were directly responsible was not ambitious: the Survey of India were responsible for the whole of the survey and brought their own equipment, which is described elsewhere in this book. It was necessary to provide the climbing party only with aneroids, compasses, reserve field-glasses, thermometers and cameras, with subsidiary apparatus for checking the aneroids at the base camps, and heavier cameras for work at lower levels. The aneroids by Cary, Porter & Co. and by Short & Mason were constructed in pairs, to operate from 15,000 to 23,000, and 22,000 to 30,000 feet respectively. They seem to have performed well on the whole, and tests made at the National Physical Laboratory since their return show that they have changed very little; but it cannot be said that their performances were very effectively controlled in the field, for until late in the season there were no trigonometrical heights available, and the climbers had little opportunity in their rather isolated circumstances of employing their aneroids to the best advantage, for purely differential work. Nor is there much to be said as yet on the value of the shortened form of George mercurial barometer, to come into action only at 15,000 feet (Cary, Porter & Co.). These instruments will find effective use only in the second season, when the reference points of the trigonometrical survey will be available as fundamental data.