THE STEUCTIJEE AJSD MOTION OF GLACIEES. 
which the ice is pressed by its own gravity, and to which it will accommodate itself, 
while preserving its general continuity, as the hand specimens do to the moulds made 
use of in the experiments. Two glacial branches unite to form a single trunk, by the 
regelation of their pressed surfaces of junction. Crevasses are cemented for the same 
reason ; and the broken ice of a cascade is reconstituted, as a heap of fragments under 
pressure become consolidated to a single mass. To those who occupy themselves with 
the external conditions merely of a glacier, it may appear of little consequence whether 
the flexures exhibited by the ice be the result of viscosity or of the principle demon- 
strated by the experiments above described. But the natural philosopher, whose vocation 
it is to inquire into the inner mechanism concerned in the production of the phenomena, 
will discern in the yielding of a glacier a case of simulated fluidity hitherto unexplained, 
and perhaps without a parallel in natm’e. 
§ 4. On the Veined Structure of Glacier Ice. 
This structure has been indifferently called the “ veined structure,” the “ banded 
structure,” the “ribboned structure,” and the “laminar structure” of glacier ice. In a 
communication to the Geological Society of France assembled at Porrentruy in September 
1838, M. Guyot gave the following interesting description of the phenomenon : — “ Since 
the word layer has escaped me, I cannot help recording as a subject of investigation for 
future observers a fact, regarding which I dare not hazard an explanation ; especially as 
I have not encountered it more than once. It was at the summit of the Gries, at a 
height of about 7500 feet, a little below the line of the first or high neve, where the 
ice passes into a state of granular snow In ascending to the origin of this latter 
(the glacier of Bettelmatten), for the purpose of examining the formation and direction 
of the great transverse fissures, I saw under my feet the surface of the glacier entirely 
covered with regular furrows, from 1 to 2 inches in width, hollowed in a half snowy 
mass, and separated by protruding plates of an ice more hard and transparent. It was 
evident that the mass of the glacier was here composed of two sorts of ice, one that of the 
furrows, still snowy and more easily melted, the other that of the plates, more perfect, 
crystalline, glassy and resistent ; and that it was to the unequal resistance which they pre- 
sented to the action of the atmosphere that was due the hollowing of the furrows and the 
protrusion of the harder plates. After having followed them for several hundred yards, 
I reached the edge of a great fissui’e, 20 or 30 feet wide ; which cutting the plates and 
fmTows perpendicularly to then* direction, and exposing the interior of the glacier to a 
depth of 30 or 40 feet, permitted the structure to be observed on a beautiful transverse 
section. As far down as my vision could reach I saw the mass of the glacier composed 
of a multitude of layers of snowy ice, each two separated by one of the plates of ice of 
which I have spoken, and forming a whole regularly laminated in the manner of certain 
calcareous slates.” 
A description of this structure, as observed upon the glacier of the Aar, was com- 
municated by Professor Foebes to the Royal Society of Edinburgh on the 6 th of De- 
