243. In the summer of 1864 Mr. Hirst and myself set out three lines of stakes across the glacier. The first line crossed the ice high up; the second a good distance lower down, and the third lower still. Even the third line, however, was at a considerable distance above the actual snout of the glacier. The daily motion of these three lines was as follows:-- First Line. Stake 1 2 3 4 5 6 7 8 9 10 11 Inches 8 12 13 13 14 13 12 12 10 7 5 Second Line. Stake 1 2 3 4 5 6 7 8 9 10 11 Inches 1 4 6 8 10 11 11 11 11 11 11 Third Line. Stake 1 2 3 4 5 6 7 8 9 10 11 Inches 1 2 4 5 6 6 7 7 5 5 4 244. Compare these lines together. You notice the velocity of the first is greater than that of the second, and the velocity of the second greater than that of the third. 245. The lines were permitted to move down wards for 100 hours, at the end of which time the spaces passed over by the points of swiftest motion of the three lines were as follows: Maximum Motion in 100 Hours. First line 56 inches. Second line 45 " Third line 30 " 246. Here then is a demonstration that the upper portions of the Morteratsch glacier are advancing on the lower ones. _In 1871 the motion of a point on the middle of the glacier near its snout was found to be less than two inches a day!_ 247. What, then, is the consequence of this swifter march of the upper glacier? Obviously to squeeze this medial moraine longitudinally, and to cause it to spread out laterally. We have here distinctly revealed the cause of the widening of the medial moraine. 248. It has been a question much discussed, whether a glacier is competent to scoop out or deepen a valley through which it moves, and this very Morteratsch glacier has been cited to prove that such is not the case. Observers went to the snout of the glacier, and finding it sensibly quiescent, they concluded that no scooping occurred. But those who contended for the power of glaciers to excavate valleys never stated, or meant to state, that it was the snout of the glacier which did the work. In the Morteratsch glacier the work of excavation, which certainly goes on to a greater or less extent, must be far more effectual high up the valley than at the end of the glacier. § 36. _Birth of a Crevasse: Reflections._ 249. Preserving the notion that we are working together, we will now enter upon a new field of enquiry. We have wrapped up our chain, and are turning homewards after a hard day's work upon the Glacier du Géant, when under our feet, as if coming from the body of the glacier, an explosion is heard. Somewhat startled, we look enquiringly over the ice. The sound is repeated, several shots being fired in quick succession. They seem sometimes to our right, sometimes to our left, giving the impression that the glacier is breaking all round us. Still nothing is to be seen.