Without knowing what might be their origin, I had
myself noticed these figures, and represented them in a diagram, part of
which is reproduced in the annexed wood-cut. I had considered them to be
compressed air-bubbles; and though I cannot, under my present
circumstances, repeat the experiment of Dr. Tyndall upon glacier-ice, I
conceive that the star-shaped figures represented upon Pl. VII. figs. 8
and 9, in my "Systeme Glaciaire," may refer to the same phenomenon as
that observed by him in pond-ice. Yet while I make this concession, I
still maintain, that besides these crystalline figures there exist
compressed air-bubbles in the angular fragments of the glacier-ice, as
shown in the above 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 different fragments. I have
explained this fact concerning the position of the compressed
air-bubbles, by assuming that ice, under various pressure, may take the
appearance it presents in each fragment with every compressed air-bubble
trending in the same direction, while their divergence in the different
fragments is owing to a change in the respective position of the
fragments resulting from the movement of the whole glacier.
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