In the evening I went with Ducrée, my guide, the only tolerable person I have seen in this country, to visit the glacier of Boisson. This glacier, like that of Montanvert, comes close to the vale, overhanging the green meadows and the dark woods with the dazzling whiteness of its precipices and pinnacles, which are like spires of radiant crystal, covered with a net-work of frosted silver. These glaciers flow perpetually into the valley, ravaging in their slow but irresistible progress the pastures and the forests which surround them, performing a work of desolation in ages which a river of lava might accomplish in an hour, but far more irretrievably; for where the ice has once descended the hardiest plant refuses to grow; if even, as in some extraordinary instances, it should recede after its progress has once commenced. The glaciers perpetually move onward, at the rate of a foot each day, with a motion that commences at the spot where, on the boundaries of perpetual congelation, they are produced by the freezing of the waters which arise from the partial melting of the eternal snows. They drag with them from the regions whence they derive their origin all the ruins of the mountain, enormous rocks, and immense accumulations of sand and stones. These are driven onwards by the irresistible stream of solid ice; and when they arrive at a declivity of the mountain, sufficiently rapid, roll down, scattering ruin. I saw one of these rocks which had descended in the spring (winter here is the season of silence and safety) which measured forty feet in every direction. The verge of a glacier, like that of Boisson, presents the most vivid image of desolation that it is possible to conceive. No one dares to approach it; for the enormous pinnacles of ice which perpetually fall, are perpetually reproduced. The pines of the forest, which bound it at one extremity, are overthrown and shattered to a wide extent at its base. There is something inexpressibly dreadful in the aspect of the few branchless trunks, which, nearest to the ice rifts, still stand in the uprooted soil. The meadows perish, overwhelmed with sand and stones. Within this last year, these glaciers have advanced three hundred feet into the valley. Saussure, the naturalist, says, that they have their periods of increase and decay: the people of the country hold an opinion entirely different; but as I judge, more probable. It is agreed by all, that the snow on the summit of Mont Blanc and the neighbouring mountains perpetually augments, and that ice, in the form of glaciers, subsists without melting in the valley of Chamouni during its transient and variable summer. If the snow which produces this glacier must augment, and the heat of the valley is no obstacle to the perpetual existence of such masses of ice as have already descended into it, the consequence is obvious; the glaciers must augment and will subsist, at least until they have overflowed this vale.