236 
INTERNAL STRUCTURE AND 
in the ice-cascades. I shall endeavor to make 
this plain to my readers in the course of the 
present article. I believe, also, that renewed 
observations will satisfy dissenting observers that 
there really exists a net-work of capillary fissures 
extending throughout the whole glacier, con- 
stantly closing and reopening, and constituting 
the channels by means of which water filtrates 
into its mass. This infiltration, also, has been 
denied, in consequence of the failure of some 
experiments in which an attempt was made to 
introduce colored fluids into the glacier. To this 
I can only answer, that I succeeded completely, 
myself, in the self-same experiments which a later 
investigator found impracticable, and that I see 
no reason why the failure of the latter attempt 
should cast a doubt upon the former. The ex- 
planation of the difference in the result may, 
perhaps, be found in the fact, that, as a sponge 
gorged with water can admit no more fluid 
than it already contains, so the glacier, under 
certain circumstances, and especially at noonday 
in summer, may be so soaked with water that 
all attempts to pour colored fluids into it would 
necessarily fail. I have stated, in my work upon 
glaciers, that my infiltration experiments were 
chiefly made at night; and I chose that time, 
because I knew the glacier would most readily 
admit an additional supply of liquid from without 
