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decrystallizes the ice, breaks down and dissects its structure, and 
there appear on the screen the same six-petalled flower-forms, but 
in this case they are water-filled cavities left by the melting of the 
crystals, showing that the block of ice is built up of regular ice- 
crystals precisely similar to the snow-flakes. How is it that ice is 
so transparent when snow is so white? It is for the same reason 
that white foam forms on transparent water. Each snow crystal 
is made up of little needles of transparent ice, but with them air is 
entangled, and the light instead of penetrating the snow is reflected 
from the ice walls of each little cavity and from the faces of each 
crystal. Then the snow loses its transparency and becomes white 
to our eyes like the foam of the sea. The cold snow-mantle keeps 
the earth warm and protects it from frost, for the snowflakes with 
the air entangled form a very bad conductor of heat. In melting 
ice, which used commonly to be spoken of as a rendering of heat 
latent, the heat applied is converted into a new kind of energy 
and employed in tearing asunder the molecules of the ice. Thus 
snow, when the thawing warmth comes to it, is not suddenly con- 
verted into disastrous floods of water; but the heat has slowly and 
gradually to do its work in opposition to a molecular force. The 
snowflake comes on a mission of beneficence to the tender herbage, 
and when its fairy forms fade before the warm breath that bids its 
beauty go, it is seen that they did but hide the raindrop, ready to 
fulfil its mission of destruction to inorganic nature, undermining 
the foundations of the round world, wearing down the “‘ everlasting 
hills.” Above the snow line upon mountains and high table lands, 
the snow does not melt, and would accumulate in vast quantities 
were it not for various processes that reduce the mass constantly. 
Slow evaporation goes on, and the mighty avalanche sometimes 
relieves the accumulating mass; but the most adequate relieving 
process is brought about by the very weight of the snow itself, 
gently squeezing its surplus into the valleys below, where it creeps 
down to warmer regions, the pressure having moulded the snow 
erystals into compact ice. Thus the immense snow-fields of the 
mountain districts are drained by the glaciers, or rivers: of ice. 
The denuding action of glaciers is of two kinds, the carrying of 
mountain debris to lower levels, and the erosion of the valley bed 
itself. The glacier in descending the valley bears with it vast 
quantities of earth, sand, stones, and blocks of rock, which collect 
to form moraines. The erosive action of the glacier is facilitated 
by means of the fine sand and stones which fall between the ice 
and the valley side. The glacier acts like a gigantic piece of very 
coarse emery paper, grinding down, smoothing, polishing and 
striating the most compact and sturdy rocks. The story of our 
snowflake’s past work upon the earth, even in our little isle would 
take many a long evening to tell. We have seen him, born of 
invisible vapour, float daintily through the air in all the exquisite 
beauty of pure symmetry, to wrap with warm shroud the tender 
