I afterwards examined the fall from the opposite side of the valley, and corroborated the observations. It is difficult, in words, to convey the force of the evidence which this glacier presents to the observer who _sees_ it; it seems in fact like a grand laboratory experiment made by Nature herself with especial reference to the point in question. The squeezing of the mass, its yielding to the force brought to bear upon it, its wrinkling and scaling off, and the appearance of the veins at the exact point where the pressure begins to manifest itself, leave no doubt on the mind that pressure and structure stand to each other in the relation of cause and effect, and that the stratification could have nothing to do with the phenomenon.
I subsequently crossed the Strahleck, descended the glaciers of the Aar, crossed the Grimsel, and examined the glacier of the Rhone. This glacier has also its grand ice-fall. In company with Prof. Ramsay, I climbed in 1858 the precipices flanking the fall at the Grimsel side. What has been stated regarding the Grindelwald ice-fall is true of that of the Rhone; the base of the cascade is _the manufactory of the structure_; and, as all the ice has to pass through this mill, the entire mass of the glacier from the base of the fall downwards is beautifully laminated.
Descending the valley of the Rhone to Viesch, I went thence to the Æggischhorn, and remained for eight days in the vicinity of the Great Aletsch glacier--the noblest ice-stream of the Alps. A highly intelligent explorer had adduced certain phenomena of this glacier as an evidence against the pressure theory of the veined structure; and I did not think myself justified in quitting the place until I had perfectly satisfied myself that the Aletsch not only presented no phenomena at variance with the pressure theory, but exhibited some which seemed fatal to the theory of the stratification.
I subsequently proceeded to Zermatt, and spent ten days on the Riffelberg, exploring the entire system of glaciers between Monte Rosa and the Mont Cervin. These glaciers exhibit, perhaps in a more striking manner than any others in the Alps, the yielding of glacier ice when subjected to intense pressure. The great western glacier of Monte Rosa, the Schwartze glacier, the Trifti glacier, and the glaciers of St. Theodule, are first spread out as wide and extensive _névés_ over the breasts of the mountains. They move down, and are finally forced into the valley containing the trunk, or Görner glacier. Here they are squeezed to narrow strips, which gradually dwindle in width until they form driblets not more than a few yards across. From the Görner Grat, or from the summit of the Riffelhorn, these parallel strips of glacier, each separated from its neighbour by a medial moraine, present a most striking and instructive appearance.