I have spoken of the many little rills arising on the surface of the ice in consequence of its melting. Indeed, the voice of the waters is rarely still on the glacier during the warm season, except at night. On a summer's day, a thousand streams are born before noontide, and die again at sunset; it is no uncommon thing to see a full cascade come rushing out from the lower end of a glacier during the heat of the day, and vanish again at its decline. Suppose one of these rivulets should fall into a deep, circular hole, such as often occur on the glacier, and the nature of which I shall presently explain, and that this cylindrical opening narrows to a mere crack at a greater or less depth within the ice, the water will find its way through the crack and filter down into the deeper mass; but the dust and sand carried along with it will be caught there, and form a deposit at the bottom of the hole. As day after day, throughout the summer, the rivulet is renewed, it carries with it an additional supply of these light materials, until the opening is gradually filled and the sand is brought to a level with the surface of the ice. We have already seen, that, in consequence of evaporation, melting, and other disintegrating causes, the level of the glacier sinks annually at the rate of from five to ten feet, according to stations. The natural consequence, of course, must be, that the sand is left standing above the surface of the ice, forming a mound which would constantly increase in height in proportion to the sinking of the surrounding ice, had it sufficient solidity to retain its original position. But a heap of sand, if unsupported, must very soon subside and be dispersed; and, indeed, these pyramids, which are often quite lofty, and yet look as if they would crumble at a touch, prove, on nearer examination, to be perfectly solid, and are, in fact, pyramids of ice with a thin sheet of sand spread over them. A word will explain how this transformation is brought about. As soon as the level of the glacier falls below the sand, thus depriving it of support, it sinks down and spreads slightly over the surrounding surface. In this condition it protects the ice immediately beneath it from the action of the sun. In proportion as the glacier wastes, this protected area rises above the general mass and becomes detached from it. The sand, of course, slides down over it, spreading toward its base, so as to cover a wider space below, and an ever-narrowing one above, until it gradually assumes the pyramidal form in which we find it, covered with a thin coating of sand. Every stage of this process may occasionally be seen upon the same glacier, in a number of sand-piles raised to various heights above the surface of the ice, approaching the perfect pyramidal form, or falling to pieces after standing for a short time erect.