The party, being resolved to make the attempt before the monsoon broke, made straight for the old advanced base camp in the Kharta valley. Thanks to General Bruce's consummate skill in the organization of mountain travel, it reached that point on the date fixed and with everybody in good health. The next duty was to establish an advanced camp one stage before the North Col, up to which porters could be brought without undue fatigue. The summit of the Lhakpa La was abandoned, and an advanced base, known as Camp No. 3, was established under the west side of the pass, close to the East Rongbuk Glacier.

The next step was to ascertain whether the road to the North Col was practicable, for when Mr. Mallory's party had travelled it the year before there had been fresh snow, and at this early season there was a danger of bare ice. Mr. Somervell and Mr. Mallory, on 13th May, with one coolie, set forth from Camp No. 3 on a reconnaissance, and found that the route they had followed the year before was one sheet of glittering ice. They saw, however, that they could cut their way into a corridor filled with good snow, which would lead them up to the foot of the final slope, and that final slope proved also to be snow and not ice. On the North Col they found a difficulty they had not looked for. Between the point at which they reached it and Everest itself was an ice cliff, which the year before they had circumvented. Now they found their way barred by a hopeless crevasse. Ultimately they discovered a route at the far end of the ice cliff, and reached the level snow from which the north ridge of Everest springs.

The next few days were occupied in bringing up supplies to Camp 4 on the North Col. They had only nine porters available, and this decided them that it would not be feasible to make two camps on the face of the mountain. They resolved to attempt to make one camp at about 26,000 feet, and from that to make their final effort.

On the 19th the four climbers, Mr. Mallory, Mr. Norton, Major Morshead, and Mr. Somervell, left Camp 3 at a quarter to nine in the morning, and an hour after mid-day were busy putting up tents and arranging stores at Camp 4 on the North Col. The sun set at 4.30, and they turned in for the night in the best of spirits. On the morrow they proposed to carry up two of the small tents, two double sleeping-sacks, food for a day and a half, cooking-pots, and two thermos flasks. They would make four loads of the stuff, which would give two porters to each load, with a man to spare.

On 20th May, Mr. Mallory got up at 5 a.m., and found that there was no sign of life in the tents in which the nine porters were quartered. The coolies had shut themselves in so hermetically that they were all unwell, and four of them were suffering badly from mountain-sickness. Only five were able to embark on the day's work. Breakfast was a slow business, because everything was frozen hard, and the dish of spaghetti which they had promised themselves could only be prepared after an elaborate process of thawing.

A start was made at 7 a.m., and everything went smoothly at first, for ropes had been fixed between their camp and the col itself, so as to help them on their return. From the col a broad snow ridge went up at an easy angle, and all the climbers felt that bodily fitness which is the assurance of success.

Then their troubles began. The first was the cold. The sun had no more warmth in it than a candle, and a bitter wind began to blow from the west. They came to an end of the ridge of stones on which they had been progressing easily, and realized that they must get some shelter from the wind by moving to the east side of the shoulder. Step-cutting was now necessary, and at that height the exertion required was extraordinarily severe. Moreover, the cold was telling upon them, and the porters especially suffered badly. After some 300 feet of steps they rested about noon under the shelter of some rocks at 25,000 feet.

It seemed to them that they could not get their loads much higher, and that they had better look out for a camp, for the porters had to return to the North Col. But a camping ground was not easy to find. At last, on the east side of the ridge, they discovered a steep slab, up to which they could level the ground. It was a poor place, for the incline was sharp, most of the floor was composed of broken rocks, and men lying down would inevitably slip on top of each other. There, however, they placed the little tents, each with its double sleeping-bag, and melted snow for their makeshift supper. The porters started back for the North Col, and the climbers, two in each bed, did their best to keep warm. All four had suffered a good deal from the cold. Mr. Norton's ear was badly swollen, three of Mr. Mallory's fingers were touched with the frost, and Major Morshead was chilled to the bone and clearly unwell.

The wind dropped in the evening, and during the night fresh snow fell. At 6.50 on the morning of 21st May they crawled from their sleeping-bags and made a laborious and exiguous breakfast, for only one thermos flask had turned up. At eight o'clock they started, none of them feeling their best after the stuffy, headachy night. Major Morshead was unable to go with them, for his illness had increased, and most regretfully the other three went on without him.

A good deal of fresh snow had fallen, but the first hours of climbing were not very difficult. The worst trouble was the perverse stratification of the mountain, for all the ledges tilted the wrong way. Slowly they crawled up, first regaining the ridge by turning west, and then following the ridge itself in the direction of the point of the North-East arête. They decided that they must turn back at about two o'clock if they were to make the descent in reasonable safety. Besides, they had to consider Major Morshead left alone in Camp 5.