Both biotite-gneiss and metamorphosed sedimentaries are crowded with dykes and sills, of all dimensions, of schorl granite or pegmatite to such an extent that this granite is frequently the predominant rock. It is highly resistant to weathering and it is doubtless due to its presence in large amount that such comparatively soft rocks as the calc-gneisses take part in forming some of the highest summits.
In the same way the scattered peaks of over 20,000 feet on the watershed between the Arun and the Tsangpo owe their prominence to their being groups of veins of a very similar granite, differing in that it contains biotite in place of schorl. Around these separate centres of intrusion are areoles of metamorphism in which the Jurassic shales have been converted into slates and phyllites.
Economically the area traversed by the Expedition is devoid of interest. Barring a little copper staining on a few boulders on moraines no traces of ore were seen.
APPENDIX IV
THE SCIENTIFIC EQUIPMENT
By A. R. HINKS, F.R.S., Secretary of the Royal Geographical Society.
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.