'Glacier Tables', 1849.
© Science Museum / Science & Society Picture Library
Colour engraving by Josiah Wood Whymper taken from 'Phenomena of Nature', published in London in 1849 for the Society for Promoting Christian Knowledge. 'On the surface of the glaciers, or streams of ice which fill the upper valleys of Alpine districts, enormous blocks or slabs of stone sometimes perch upon stems of ice like huge mushrooms. They are called 'Glacier Tables' and are formed when ice at the surface of the glacier sinks all round the stone while the ice immediately beneath it is protected from the sun and the rain as by an umbrella.'