Chemical Industries, General Empty oxygen cylinder, 1922

Chemical Industries, General Empty oxygen cylinder, 1922. Oxygen cylinder from the British 1922 Everest Expedition, shown with a modern oxygen cynlinder and breathing mask, similar to those used in the successful 1953 expedition. Because of the lower atmospheric pressure at higher altitudes, there is less oxygen in any given volume of air than at sea level. On the summit of Everest, 8848 m above sea level, there is 66% less oxygen. Expeditions therefore carried pressurised bottles of oxygen for climbers to breathe while at high altitude. The 1922 expedition to Everest was the first to be equipped in this way, and reached over 8000 m. Some believed that climbing at such extreme altitudes was impossible without supplementary oxygen, but in 1978 Reinhold Messner and Peter Habeler made the first successful ascent of EverestÊ without it. ©SSPL/Science Museum