greatest depth of snow through which I waded reaching, when I stood erect, to within three inches of my breast. [Sidenote: SWIFT DESCENT. 1859.] The men returned; dinner was prepared and consumed; the disorder which we had created made good; the rooms were swept, the mattresses replaced, and the shutters fastened, where this was possible. We locked up the house, and with light hearts and lithe limbs commenced the descent. My aim now was to reach the source of the Arveiron, to examine the water and inspect the vault. With this view we went straight down the mountain. The inclinations were often extremely steep, and down these we swept with an avalanche-velocity; indeed usually accompanied by an avalanche of our own creation. On one occasion Balmat was for a moment overwhelmed by the descending mass: the guides were startled, but he emerged instantly. Tairraz followed him, and I followed Tairraz, all of us rolling in the snow at the bottom of the slope as if it were so much flour. My practice on the Finsteraarhorn rendered me at home here. One of the porters could by no means be induced to try this flying mode of descent. Simond carried my theodolite box, tied upon a crotchet on his back; and once, while shooting down a slope, he incautiously allowed a foot to get entangled; his momentum rolled him over and over down the incline, the theodolite emerging periodically from the snow during his successive revolutions. A succession of _glissades_ brought us with amazing celerity to the bottom of the mountain, whence we picked our way amid the covered boulders and over the concealed arms of the stream to the source of the Arveiron. The quantity of water issuing from the vault was considerable, and its character that of true glacier water. It was turbid with suspended matter, though not so turbid as in summer; but the difference in force and quantity would, I think, be sufficient to account for the greater summer turbidity. This character of the water could only be due to the grinding motion of the glacier upon its bed; a motion which seems not to be suspended even in the depth of winter. The temperature of the water was the tenth of a degree Centigrade above zero; that of the ice was half a degree below zero: this was also the temperature of the air, while that of the snow, which in some places covered the ice-blocks, was a degree and a quarter below zero. [Sidenote: VAULT OF THE ARVEIRON. 1859.]