moraine. Other stones are thrown up on the banks or shores of the glacier. If these be very steep, the blocks fall into holes and openings left between the ice and the rock, where they are ground and chafed, and serve to polish the rock itself, producing grooves and scratches in the direction of the moving ice. When the shore has a more gradual slope, the blocks are frequently stranded, and the heat of the ground usually causes the ice to sink at the sides, forming a sort of trough or hollow, in which the blocks accumulate in a ridge. It was along this ridge that we had to pick our way for a considerable distance. The climbing up and down among these stony masses was difficult and even dangerous, for some of them were so delicately poised, that a step was often sufficient to set them in motion and produce a fall. It is quite impossible to form a pathway over this lateral moraine, because the glacier changes its dimensions in different seasons and in different years. When the glacier, like a swollen torrent, occupies its bed to an unusual depth, the moraine is uplifted with it; and when the warmth of summer reduces the bulk of the ice, the blocks are often left on rocky shelves at a considerable height above.

When two glaciers from separate sources unite in a common valley, exactly as two rivers would do, the edging moraines common to each unite upon the surface, and mark, by a band of stones, often for miles, the actual separation of the two

ice streams. This new moraine of course occupies the centre of the compound stream, and is the medial moraine figured at p. 120.

Proceeding for some distance along the lateral moraine already noticed, we arrived at the foot of a perpendicular cliff much worn by the action of the ice, the furrows being marked in distinct parallel lines. In places where glaciers have long ceased to exist, these marks are often visible, by which means the icy stream can be traced to places where its presence might not otherwise have been suspected.

We had not yet left the moraine, when a loud but dull sound, something like that of a musket, was heard, which brought down a shower of blocks, and shook and disturbed the rough road, which we were about to quit. The noise was produced by the opening of a crack, or crevasse as it is called, in the ice. We now stepped upon the bare ice, which at this part of the glacier was much smoother than at the lower part, and afforded excellent walking compared with the toilsome path we had just left. The sun was shining brightly, and had thawed the surface sufficiently to give a certain degree of roughness; we therefore proceeded at a rapid pace over the ice, until we were suddenly stopped by a yawning gulf, or crevasse, about eight or ten feet wide, and extending some sixty feet across the glacier. On turning the edge of this, and proceeding a little higher up, we came to another, which in like manner we avoided; but

soon the crevasses became so numerous as to bewilder and confuse the stranger. The guides frequently paused to consult. Sometimes, with the assistance of a long pole spiked with iron,* without which it would be quite impossible to travel among glaciers, we leaped across a crevasse; but this required caution, on account of the wide gaping mouths on the other side. Sometimes, to prevent a tiresome walk along the edge of a crevasse, the guides would form a kind of bridge with their batons, over which to help the traveller. The depth of these crevasses varies according to the thickness of the ice and their position in the glacier; on looking into them, the ice appears of a beautiful blue colour, but the eye cannot penetrate far. The crevasses are of course most dangerous when covered with a thin coating of snow: many travellers and hunters have sunk into the abyss, and have been lost.

On continuing to ascend the glacier, the advancing heat of the day had its effect upon the ice, in thawing the water of a number of pools which were frequently met with. They are called baignoirs, and are formed from small holes or cavities in the ice. The warmth of the day also set in motion innumerable rills of water, which run along the hollows or furrows of the ice, and, uniting in larger streams, pour down in bold cascades into the crevasses. On continuing to advance, a loud

* This pole is called a baton in French Switzerland, and an alpenstock in German Switzerland.

throbbing sound like the clack of a mill was heard, which the guides called le moulin. On advancing towards it, an abundant cascade, formed by the union of thousands of little rills, was pouring its waters into a cylindrical hole, on looking into which the stream was seen divided into two, each branch descending through a separate hole into the icy bowels of the glacier. As the holes were of considerable size, the disturbance of the air probably caused the clacking sound. A beautiful blue light, gradually fading into blackness, permitted a portion of the interior to be seen. It is remarkable that whatever be the state or progress of the glacier, these moulins are found in almost exactly the same position; that is, opposite to the same fixed objects on the side of the glacier.

The water on the surface of the ice, unlike the turbid stream which issues from the foot of the glacier, is of exquisite purity. The guides filled a glass with it, and it was welcome and refreshing; the rill sparkling at our feet was of icy coldness, while the hot summer's sun, which made it sparkle, was overwhelming us with heat.

It was here that Mr. Forbes, in the summer of 1842, performed his beautiful experiments to determine the motion of the glacier. Many of the marks made by him on the rocks and stones still remain, and were examined with the greatest interest.

After walking a few miles over the glacier, the valley, along which we had hitherto proceeded,

expanded into an extensive plain, the centre of three valleys, each of which poured its icy stream into this common receptacle. The crevices are here of enormous size, and of great depth; the guides have sounded a moulin above 350 feet deep. Basins are also hollowed out in the ice, containing water of an exquisite blue colour. Here the origin of the medial moraine can be well traced. At the meeting of the icy streams, the masses of rock, previously forming the lateral moraines,now move along in the centre. One of these is an enormous block of granite, having one of its sides hollow, and forming a well-known refuge for the chamoishunters, and the few travellers who intend to pass a night on the glacier. Forbes passed some nights here, and found it by no means disagreeable in fine weather. The glacier is in great measure concealed by its lofty embankments, which shelter it from the chilling winds; the slopes around are grassy, and dotted here and there with juniper

bushes.

At the broad part of the glacier at which we have now arrived, we quitted the ice, and began to ascend the steep rock at the foot of the Aiguille du Moine. After much painful climbing, we arrived at a grassy platform, just large enough to accommodate our party of four; and as we were exhausted by the heat, and by this rude essay at mountaineering, we sat down to dine. Our tablecloth was spread near the edge of a precipice a thousand feet deep; behind us rose the Moine,