The Mer de Glace ('Sea of Ice') near Chamonix, with the summit of the Grandes Jorases in the distance. The Mer de Glace, which descends from the Mont Blanc masif, is the largest glacier in the French Alps. It is 7 kilometres in length, up to 1950 metres wide, and the ice is up to 400 metres thick in places. From a collection of 57 albumen photographs of rock and glacial formations in the United Kingdom, Europe, North America and Asia.
© Science Museum / Science & Society Picture Library