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strong pressure the ice had been melted and had frozen again 
when the pressure was removed. 
The consideration of this remarkable property goes far to 
explain how a mass of glacier-ice can behave like a viscous 
body. If the bed of the glacier were smooth, and the ice 
could move on it without friction, it would of course slide 
down by its own weight. But the bed not being smooth, 
but offering projections of rock, the pressure exerted by these 
obstacles on the ice will be very great ; the ice cannot yield 
like a viscous body would, but it can melt if time be given it, 
and this comes to much the same thing. Usually the water 
formed by the melting of the ice is forced out of the way, and 
the mass of ice moves forward. In melting, also, the ice 
takes up heat, and this is supplied by the surrounding ice 
which is thus cooled below 0° C. Consequently, when the 
water shifts its position slightly, to escape from pressure, it 
finds itself in contact with cold ice and is thus frozen again. 
In this experiment the wire is a good conductor of heat, and 
the circumstances are favourable for the transfer of heat 
from behind the wire when the water is freezing, to the point 
of pressure under the wire where the ice is melting. There 
is thus in each minute as much ice re-formed as is melted, and 
the wire passes through, leaving the block entire. In the 
case of a glacier, all the water from the melting ice will not 
be re-frozen, a considerable proportion will escape, and find 
its way down between the ice and rock or through the 
crevasses of the ice, escaping in the stream of water, which 
issues from the foot of every glacier. And even of that water 
which is re-frozen, it must be remembered that while free to 
move as water, it will tend to descend by its own weight, and 
when re- frozen will occupy a lower position than before. 
There is also the large amount of heat received from the sun 
upon the surface of the glacier, and that resulting from friction 
over the bed, all of which causes the melting of a considerable 
