The four men did not waste time next morning on the North Col, for they were tormented by thirst and hunger. It took them six hours to reach Camp 3, for they had to make a staircase beneath the new snow which the porters could use, in order to fetch down their baggage, since they did not intend to spend the night at Camp 3 without their sleeping-bags. At midday they were back in comparative comfort, with certain solid conclusions as the result of the venture. One was as to the difficulties of new snow and the precariousness of the weather; another was as to the unexpected capacity of the porters. But the most important was as to the need of oxygen. They had reached a point very little below 27,000 feet, and that left 2,000 feet to be surmounted before the summit was reached. For success, a higher camp was needed than Camp 5, and the men who started from it must, if possible, have an extra stimulus to counteract the malign effects of altitude. If Everest chose to clothe itself with air containing less oxygen than a man needed, the defect must be supplied. If a climber used extra clothes to counteract the cold, he must use some extra device to supplement the atmosphere. IV We come now to the second attempt of 1922, in which oxygen was used. Certain eminent scientists at home had held that Everest could never be conquered without its aid, and the expedition had brought a very full equipment--oxygen stored in light steel cylinders, and a somewhat complex apparatus for its use. There had been oxygen drill parades among the party, and perhaps it might have been well had they used it straight away for one main attempt, instead of making the first effort without it. Unfortunately the apparatus needed overhauling, and it was not till 22nd May, when Mr. Mallory and his party were coming down from the mountain, that four sets were ready for use. As to the legitimacy of such a device in mountaineering, Mr. Finch's arguments are final.