276 INTERNAL STRUCTURE AND 
cut. I had considered them to be compressed air- 
bubbles ; and though I cannot, under my pres- 
ent circumstances, repeat the experiment of Dr. 
Tyndall upon glacier-ice, I conceive that the star- 
shaped figures represented upon PI. VII. Figs. 
8 and 9, in my “ Systeme Glaciaire,” may re- 
fer to the same phenomenon as that observed 
by him in pond-ice. Yet while I make this con- 
cession, I still maintain, that besides these crys- 
talline figures there exist compressed air-bub- 
bles in the angular fragments of the glacier-ice, 
as shown in the preceding wood-cut ; and that 
these bubbles are grouped in sets, trending in 
the same direction in one and the same fragment, 
and diverging under various angles in the differ- 
ent fragments. I have explained this fact con- 
cerning the position of the compressed air-bub- 
bles, by assuming that ice, under various press- 
ure, may take the appearance it presents in each 
fragment with every compressed air-bubble trend- 
ing in the same direction, while their diver- 
gence in the different fragments is owing to a 
change in the respective position of the frag- 
ments resulting from the movement of the whole 
glacier. I have further assumed, that through- 
out the glacier the change of the snow and porous 
ice into compact ice is the result of successive 
freezing, alternating with melting, or at least 
with the resumption of a temperature of 32° 
