When fluid, it would contribute to the advance of the mass in
proportion to its quantity; but when frozen, its expansion would produce
a displacement corresponding to the greater volume of ice as compared
with water; add to this that while trickling through the mass it will
loosen and displace the particles of already consolidated ice. I have
already said that I did not intend to trespass on the ground of the
physicist, and I will not enter here upon any discussion as to the
probable action of the laws of hydrostatic pressure and dilatation in
this connection. I will only state, that, so far as my own observation
goes, the movement of the glacier is most rapid where the greatest
amount of moisture is introduced into the mass, and that I believe there
must be a direct relation between these two facts. If I am right in
this, then the motion, so far as it is connected with infiltrated
moisture or with the dilatation caused by the freezing of that moisture,
will, of course, be most rapid where the glacier is most easily
penetrated by water, namely, in the region of the _neve_ and in the
upper portion of the glacier-troughs, where the _neve_ begins to be
transformed into more or less porous ice.
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