North Col
On 10 May Mallory and Somervell left base camp to erect Camp IV on the North Col. They arrived in Camp II only two and a half hours later. On 11 May they started to climb on the North Col. This camp was at a height of 7000 m and was supported with food. The further plan was to do a first ascent trial by Mallory and Somervell without supplemental oxygen, then followed by a second climb by Finch and Norton with oxygen. However, these plans failed as a majority of the climbers became ill. So it was decided that the (more or less) healthy climbers Mallory, Somervell, Norton and Morshead should climb together.