You advance slowly, passing round the crevasses, or on the snow bridges of dubious strength. Then the rope plays its part. It is stretched out over these dangerous transits; if the snow bridge yields, the guide or traveller remains hanging over the abyss. He is drawn beyond it, and gets off with a few bruises. Sometimes, if the crevasse is very wide but not deep, he descends to the bottom and goes up on the other side. In this case it is necessary to cut steps in the ice, and the two leading guides, armed with a sort of hatchet, perform this difficult and perilous task. A special circumstance makes the entrance on the Bossons dangerous. You go upon the glacier at the base of the Aiguille-du-Midi, opposite a passage whence stone avalanches often descend. This passage is nearly six hundred feet wide. It must be crossed quickly, and as you pass, a guide stands on guard to avert the danger from you if it presents itself. In 1869 a guide was killed on this spot, and his body, hurled into space by a stone, was dashed to pieces on the rocks nine hundred feet below. [Illustration: Crevasse and Bridge.] We were warned, and hastened our steps as fast as our inexperience would permit; but on leaving this dangerous zone, another, not less dangerous, awaited us. This was the region of the “seracs,”—immense blocks of ice, the formation of which is not as yet explained. [Illustration: View of the “Seracs”.] These are usually situated on the edge of a plateau, and menace the whole valley beneath them. A slight movement of the glacier, or even a light vibration of the temperature, impels their fall, and occasions the most serious accidents. [Illustration: View of the “Seracs”.] “Messieurs, keep quiet, and let us pass over quickly.” These words, roughly spoken by one of the guides, checked our conversation. We went across rapidly and in silence. We finally reached what is called the “Junction” (which might more properly be called the violent “Separation”), by the Côte Mountain, the Bossons and Tacconay glaciers. At this point the scene assumes an indescribable character; crevasses with changing colours, ice-needles with sharp forms, seracs suspended and pierced with the light, little green lakes compose a chaos which surpasses everything that one can imagine. Added to this, the rush of the torrents at the foot of the glaciers, the sinister and repeated crackings of the blocks which detached themselves and fell in avalanches down the crevasses, the trembling of the ground which opened beneath our feet, gave a singular idea of those desolate places the existence of which only betrays itself by destruction and death. [Illustration: Passage of the “Junction”.]