Image Description from historic lecture booklet: "Every large snow-field is also an ice-field, for where snow accumulates to great depth and lies long upon the surface, it is changed to ice. the beginning of this change may be seen in the snow a few days after it falls, for it soon loses its light, flaky character and becomes granular, so that it feels harsh to the hand. The change is very distinct in the last banks of snow in the spring. They are made up of coarse grains (granules) of ice, sometimes as larges as peas. The change from flakes of snow to granules of ice is due, in part, to the melting of the snow and the freezing of the water. If there is much snow, it is compressed by its own weight, and after being compacted in this way, the freezing of the sinking water binds the granules together. By this and perhaps other process, the large part of every thick snow-field becomes an ice-field merely coated over with snow."

Original Collection: Visual Instruction Department Lantern Slides

Item Number: P217:set 012 002

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