Prof. Huxley on the Structure of Glacier Ice. 249 
and the west shore of the Mer de Glace, where the veins were 
well developed, their planes having a general north and south 
direction, but dipping at an angle of about 70° towards the 
centre of the glacier. On the northern aspect of the ice I cut 
away the superficial layer, so as to form two faces of a cube 
of about a foot in the ‘side on the deep ice. One of these 
faces looked westward, and was consequently nearly parallel to 
the cleavage; the other looked northward, and was therefore 
nearly perpendicular to it. Perpendicular to the west face, and 
therefore to the structural planes, I bored a hole with an auger, 
about an inch in diameter and 9 inches long, and just suffi- 
ciently inclined to the horizon to hold the infusion of logwood, 
with which I filled it. I then thinned away the north face of 
the cube very carefully until the north wall of the hole was 
less than 2 inches in thickness—until, in fact, I could see the 
dark fluid through the substance of the several blue veins which 
it traversed with perfect distinctness. 
For two hours not the slightest trace of leakage or infiltra- 
tion into the substance of the ice forming the walls of this 
cavity could be observed; and the contour of the contained 
liquid remained perfectly sharp and well defined. It then began 
to leak at one point near its upper end through a small crack 
in the white ice, which led directly outwards. The hquid spread 
neither up nor down in the crack. Four hours afterwards no 
change whatever had taken place in the liquid contained in the 
lower part of the hole. At this time you joined me upon the ice, 
and you will recollect that I carefully thinned away the wall with 
a sharp knife until in some parts it was not more than + of an inch 
thick. Still no infiltration occurred. The knife at length acci- 
dentally penetrated the wall, and the liquid at once flowed out. 
I then poured some clean water through the hole, and all trace 
of the coloured infusion was at once so thoroughly removed, 
that, on cutting away one wall, the other appeared perfectly 
clean and of its natural aspect. 
I have given the details of this one experiment in order to 
show in what manner all were made 3 but it is unnecessary to 
be equally prolix with regard to the others. Suffice it to say, 
that, whether the holes were bored perpendicular to the strue- 
ture or parallel with it, or at any intermediate angle, whether 
in white ice or in a blue vein, the result was precisely the same, 
not a particle of fluid making its way into the surrounding sub- 
stance of the ice along the veins, nor in most cases in any other 
way. Occasionally a leakage would take place in the manner 
described above, but the fissures in these cases were gross and 
visible, and their direction had no reference whatsoever to that 
of the structure. Indeed, as the leakage always took place 
