A GLACIER "BLOWER." 1857.
On the 17th I penetrated with Simond through thick gloom to the Tacul; on the 18th we set stakes at the same place: on the same day, while crossing the medial moraine of the Talèfre, a little below the cascade, a singular noise attracted my attention; it seemed at first as if a snake were hissing about my feet. On changing my position the sound suddenly ceased, but it soon recommenced. There was some snow upon the glacier, which I removed, and placed my ear close to the ice, but it was difficult to fix on the precise spot from which the sound issued. I cut away the disintegrated portion of the surface, and at length discovered a minute crack, from which a stream of air issued, which I could feel as a cold blast against my hand. While cutting away the surface further, I stopped the little "blower." A marmot screamed near me, and while I paused to look at the creature scampering up the crags, the sound commenced again, changing its note variously—hissing like a snake, singing like a kettle, and sometimes chirruping intermittently like a bird. On passing my fingers to and fro over the crack, I obtained a succession of audible puffs; the current was sufficiently strong to blow away the corner of a gauze veil held over the fissure. Still the crack was not wide enough to permit of the entrance of my finger nail; and to issue with such force from so minute a rent the air must have been under considerable pressure. The origin of the blower was in all probability the following:—When the ice is recompacted after having descended a cascade, it is next to certain that chambers of air will be here and there enclosed, which, being powerfully squeezed afterwards, will issue in the manner described whenever a crack in the ice furnishes it with a means of escape. In my experiments on flowing mud, for example, the air entrapped in the mass while descending from the sluice into the trough, bursts in bubbles from the surface at a short distance downwards.
A DIFFICULT LINE. 1857.
I afterwards examined the Talèfre cascade from summit to base, with reference to the structure, until at the close of the day thickening clouds warned me off. I went down the glacier at a trot, guided by the boulders capped with little cairns which marked the route. The track which I had pursued for the last five weeks amid the crevasses near l'Angle was this day barely passable. The glacier had changed, my work was drawing to a close, and, as I looked at the objects which had now become so familiar to me, I felt that, though not viscous, the ice did not lack the quality of "adhesiveness," and I felt a little sad at the thought of bidding it so soon farewell.
At some distance below the Montanvert the Mer de Glace is riven from side to side by transverse crevasses: these fissures indicate that the glacier where they occur is in a state of longitudinal strain which produces transverse fracture. I wished to ascertain the amount of stretching which the glacier here demanded, and which the ice was not able to give; and for this purpose desired to compare the velocity of a line set out across the fissured portion with that of a second line staked out across the ice before it had become thus fissured. A previous inspection of the glacier through the telescope of our theodolite induced us to fix on a place which, though much riven, still did not exclude the hope of our being able to reach the other side. Each of us was, as usual, armed with his own axe; and carrying with us suitable stakes, my guide and myself entered upon this portion of the glacier on the morning of the 19th of August.
"NOUS NOUS TROUVERONS PERDUS!" 1857.
I was surprised on entering to find some veins of white ice, which from their position and aspect appeared to be derived from the Glacier du Géant; but to these I shall subsequently refer. Our work was extremely difficult; we penetrated to some distance along one line, but were finally forced back, and compelled to try another. Right and left of us were profound fissures, and once a cone of ice forty feet high leaned quite over our track. In front of us was a second leaning mass borne by a mere stalk, and so topheavy that one wondered why the slight pedestal on which it rested did not suddenly crack across. We worked slowly forwards, and soon found ourselves in the shadow of the topheavy mass above referred to; and from which I escaped with a wounded hand, caused by over-haste. Simond surmounted the next ridge and exclaimed, "Nous nous trouverons perdus!" I reached his side, and on looking round the place saw that there was no footing for man. The glacier here, as shown in the [frontispiece], was cut up into thin wedges, separated from each other by profound chasms, and the wedges were so broken across as to render creeping along their edges quite impossible. Thus brought to a stand, I fixed a stake at the point where we were forced to halt, and retreated along edges of detestable granular ice, which fell in showers into the crevasses when struck by the axe. At one place an exceedingly deep fissure was at our left, which was joined, at a sharp angle, by another at our right, and we were compelled to cross at the place of intersection: to do this we had to trust ourselves to a projecting knob of that vile rotten ice which I had learned to fear since my experience of it on the Col du Géant. We finally escaped, and set out our line at another place, where the glacier, though badly cut, was not impassable.
FAREWELL TO THE MONTANVERT. 1857.
On the 20th we made a series of final measurements at the Tacul, and determined the motion of two lines which we had set out the previous day. On the 21st we quitted the Montanvert; I had been there from the 15th of July, and the longer I remained the better I liked the establishment and the people connected with it. It was then managed by Joseph Tairraz and Jules Charlet, both of whom showed us every attention. In 1858 and 1859 I had occasion to revisit the establishment, which was then managed by Jules and his brother, and found in it the same good qualities. During my winter expedition of 1859 I also found the same readiness to assist me in every possible way; honest Jules expressing his willingness to ascend through the snow to the auberge if I thought his presence would in any degree contribute to my comfort.
We crossed the glacier, and descended by the Chapeau to the Cascade des Bois, the inclination of which and of the lower portion of the glacier we then determined. The day was magnificent. Looking upwards, the Aiguilles de Charmoz and du Dru rose right and left like sentinels of the valley, while in front of us the ice descended the steep, a bewildering mass of crags and chasms. At the other side was the pine-clad slope of the Montanvert. Further on the Aiguille du Midi threw its granite pyramid between us and Mont Blanc; on the Dôme du Goûter the séracs of the mountain were to be seen, while issuing as if from a cleft in the mountain side the Glacier des Bossons thrust through the black pines its snowy tongue. Below us was the beautiful valley of Chamouni itself, through which the Arve and Arveiron rushed like enlivening spirits. We finally examined a grand old moraine produced by a Mer de Glace of other ages, when the ice quite crossed the valley of Chamouni and abutted against the opposite mountain-wall.