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338 Ji Be Conte on the Descent of Glaciers. 
0:00524,—he obtains, by the formula (2), numerical results, rela- 
tive to the daily motion, sufficiently accordant (considering the — 
nature of the problem) with those given by observation. i 
Without stopping to investigate whether a mass of matter hav- 
ing the structure and internal constitution of the glacial ice, woul 
supply the same mechanical conditions as a metallic sheet or bar ; 
it seems to me, that, whilst Mr. Moseley’s reasoning may be per- 
fectly applicable to ordinary cases of solid bodies resting upon in- 
clined planes, its application as a cause of Glacial motion is pe- 
culiarly unfortunate. There are physical considerations which 
render this cause totally inoperative in the case of glaciers. 
be Hi ory is founded on a mistake as to a physical fact, 
arising from a strange oversight of the peculiar laws of latent 
heat. Itis not a fact, that “variations in the quantity and tem- 
perature of the water,” which percolates from the surface of the 
glaciers throughout their entire masses, would subject them to 
corresponding variations of internal temperature. For the water 
cannot permeate the capillary fissures without melting the ice, un- 
til its temperature is reduced to 32° Fahr. In other words, it is im- 
possible for water to remain in contact with ice, and both of them 
retain their respective physical states, unless they are both at the 
temperature of melting ice. If warm water begins to descend, 
it melts the superficial ice and its temperature is speedily reduced 
to 32° Fahr. If the interior mass of ice is below the freezing 
point the water will solidify, and thus arrest the circulation :—so 
3: It appears very clearly from the thermometrical experiments 
of Prof. Agassiz, and from the observations of Prof. J. D. Forbes, 
that from 28° to 32° Fahr., is the habitual temperature of the 
great mass of a glacier; that the most rigorous nights in winter 
propagate an intense cold to but a very small depth ; and that the 
temperature of the interior and lower parts is not sensibly lowered, 
even by the prolonged cold of winter. Hence it follows, that 
even during the winter, the cause which the theory demands (va- _ 
riations of temperature), is practically inoperative, when consid- 
