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452 
GLACIERS. 
its tenacity more resembled glass or granite than the 
familiar ice at home, was not a solitary one. The pre- 
ceding sketch will exhibit an equally marked curva- 
ture in a larger mass, where the gravitating pressure 
was applied at the two extremities. 
Contorted ices, natural bridges, and, as the season 
fluence which temperature exerts upon its condition at 
points below that of congelation, 32°. 
I have already described the only glacier which I 
had an opportunity of surveying. It reminded me of 
La Brenva ; and although I overlooked the ribboned 
structure, not having seen then the detailed work of 
Professor Forbes, I recollect that it had the peculiar 
scalloped shell summit, which he has regarded as il- 
lustrative of mechanical advance. 
It was from the icebergs, however, that formed so 
characteristic a feature of the scene before us, that we 
derived our best idea of the glaciers from which they 
had come. To the eye they presented almost infinite 
diversity ; but it required very little generalization to 
reduce them all to a few simple primary forms. 
Thus the vertical fracture of the glacier, which 
would indicate the formation of a berg by debacle, 
would divide the mass into parallelopipedons or other 
rudely symmetrical solids; and where the surface of 
the original plateau was parallel to its base, the de- 
tached mass would float evenly upon the waters, a 
advanced, nodding, pen- 
dulous, stalactitic hum- 
mocks, were not unfre- 
quent. These had a dou- 
ble interest, as bearing 
- not only on the plastici- 
ty of ice, but on the in- 
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