From one thing only did M. Rendu shrink; and it is the thing regarding which we are still disunited. He shrank from stating the physical quality of the ice in virtue of which a glacier moved like a river. He demands experiments upon snow and ice to elucidate this subject. The very observations which Professor Forbes regards as proofs are those of which we require the physical explanation. It is not the viscous flow, if you please to call it such, of the glacier as a whole that here concerns us; but it is the quality of the ice in virtue of which this kind of motion is accomplished. Professor Forbes sees this difference clearly enough: he speaks of "fissured ice" being "flexible" in hand specimens; he compares the glacier to a mixture of ice and sand; and finally, in a more matured paper, falls back for an explanation upon the observations of Agassiz regarding the capillaries of the glacier.[L]
FOOTNOTES:
[A] Expressions such as "last summer," "last autumn," "recently," will be taken throughout in the sense which they had in the early half of 1860, when this book was first published.—L. C. T.
[B] 'Memoir,' p. 77.
[C] P. 75.
[D] P. 71.
[E] 'Philosophical Magazine,' 1859.
[F] 'Memoir,' p. 69.
[G] Page 80.
[H] Page 95.