Note 160 — Chapter XIII

I need scarcely say that I adopt the explanation of glacier motion given by Forbes. "The fuller consideration of the physical properties of glacier ice leads essentially to the same conclusions as those to which Forbes was led forty-one years ago by the study of the larger phenomena of glacier motion, that is, that the motion is that of a slightly viscous mass, partly sliding upon its bed, partly shearing upon itself under the influence of gravity."—Trotter, Proc. Royal Society of London, xxxviii. 107.