The scientific work to account for the sliding properties of snow and ice is not abundant. Osborne Reynolds suggested that a skate slid on ice owing to the lubrication caused by pressure-melting. Bowden and Hughes, after studying the measurements made by the last-named as physicist to our glaciological expedition to the Jungfraujoch in 1938, formed the opinion that this could not alone account for the action of ski sliding upon snow. I had reached a somewhat similar conclusion some years ago after a study of the structure of snow crystals on the surface of snow fields.