THE STEHCTIJEE AND MOTION OP G-LACIEES. 
341 
me at the time that the blue veins of glaciers, which indeed I had not seen, but which 
had been the subject of repeated conversations between Professor Studee of Berne, Pro- 
fessor Eschee von dee Linth, and myself, might be explained in the same manner. When, 
therefore, I reached the Phone glacier for the first time, I walked along it for a con- 
siderable extent, and directed my attention particularly to the structure. I repeated 
this on the other glaciers which I visited during my excursion. I did not indeed 
pursue the subject so far into detail as to be able in all cases to deduce the blue veins 
from the existing conditions of pressure, but the correctness of the general explanation 
impressed itself upon me more and more. This was particularly the case in the glacier 
of the Rhone, where I saw the blue bands most distinctly, and where also their position 
harmonized with the pressure endured by the glacier when it was forced to change the 
dhection of its motion. You can therefore imagine how astonished I was to learn that 
at the same time, and on this very glacier among others, you had been making the same 
investigations.” It ought also to be remarked, that a similar thought occurred to 
Mr. SoEBT, from whom after his return from Switzerland one of us received a note, in 
which pressure was referred to as the possible cause of the veined structure of glacier ice. 
A fine example of ice lamination is that produced by the mutual thrust of two con- 
fluent glaciers. The junction of 
the Tauter Aar and Finster Aar 
glaciers to form the glaciers of the 
Unter Aar is a case in point, and 
the results obtained with a model 
of this glacier were highly inter- 
esting. Fig. 9 is a sketch of the 
trough in which the experiments 
were made. The branch termina- 
ting at UL is meant to represent the 
Tauter Aar glacier ; that ending at 
FN the Finster Aar branch. The 
point at A represents the “Ab- 
schwung,” so often referred to in 
the works of M. Agassiz. B and 
B' are two boxes with sluice fr’onts, 
from which the mud flows into the 
trough, The object was to observe 
the mechanical state of the mass 
along the line of junction of the 
two streams, and along their re- 
spective centres, and compare the 
result with the observations upon 
the glacier itself. The mud was 
Eig. 9. 
first permitted to flow simultaneously from both 
