256 Prof. Huxley on the Structure of Glacier Ice. 
singular that in (12) Prof. Agassiz states that “the angular 
fragments and the capillary fissures seem to disappear the mo- 
ment the ice is covered,”’ while in (13) the operation is said to 
take some time; but, supposing the fact to be as Prof. Agassiz 
says, it seems to me to be in the highest degree probable that 
the fissures have reunited during the interval. At any rate, I 
cannot admit Prof. Agassiz’s explanation, for surely loose gravel 
is not exactly a substance calculated to “ intercept air and 
keep fissures full of water.” 
It would take up too much space, and serve no useful pur- 
pose, to quote at length the account Prof. Agassiz gives of his 
infiltration experiments (Syst. Glaciaire, pp. 170-179). Those 
who will turn to the original, will find that they are all vitiated 
by the absence of any discrimination between the deep and the 
superficial ice, and between “ capillary fissures” and accidental 
cracks. Not one of Prof. Agassiz’s experiments affords the 
slightest evidence that capillary fissures are a primitive and 
essential constituent of the structure of the deep ice of a glacier. 
The experiments of the Messrs. Schlagintweit (/. c. p. 12) ap- 
pear to me to be equally inconclusive; these gentlemen, like 
Prof. Agassiz, having omitted to take the precaution of clearing 
away the superficial layer from the mouth of the cavity to be 
filled with the infiltration fluid. Unless this be done, the super- 
ficial layer sucks up the coloured liquid, which becomes diffused 
in the way they describe. And if the cavity (as may readily 
happen, especially with such large ones as those employed by 
these experimenters) communicates by an accidental fissure with 
some other part of the surface of the glacier (say the wall of a 
crevasse, or the roof of such a cavity as Prof. Agassiz’s infiltra- 
tion gallery), it should be well remembered that the fluid which 
drains through will not run out in a stream from the termina- 
tion of the crack, unless the superficial layer has been cleared 
away ; otherwise, it will fill the fissures of the superficial layer 
and appear as a great patch. The observer then, seeing nothing 
but fissures full of coloured infusion at each end of the course 
of the fluid, naturally enough imagines that in its intermediate 
course the fluid has traversed similar fissures. This conclusion 
would be at once dissipated by cutting away the superficial 
layer and laying open the infiltration cavity,—a precaution which 
does not seem to have occurred to either Prof. Agassiz or the 
Messrs. Schlagintweit. 
I will conclude with a few words upon the relation of struc- 
ture to the arrangement of dirt upon the surface of a glacier. 
The great “ dirt-bands” have never been proved to be connected 
with any peculiar structure of the ice on which they lie, and it 
