 1910-1912 saw him engaged on triangulation in Kashmir, where he learned climbing techniques, taught himself to ski and went on to make a stereographic land survey.Mason returned to India after the First World War and began preparing for his most important scientific project, the exploration of the Shaksgam Valley, in 1926.At that time the only westerner to see the valley had been Francis Younghusband, whose book "The heart of a continent