the want of mules, for we combine the strength of a man with the weight of a child. We can bound from rock to rock more lightly than the chamois, and can leap across chasms six times broader, than any we could venture to take on the surface of the earth. Were it not for this convenient lightness, the task would be impracticable. The rocks have all their natural angularity. There has been no weathering to mitigate the roughness; and chasms and sharp peaks face us at every turn. We at last gain the summit, 7500 feet above the plain outside. An astounding spectacle presents itself, when we view the interior of this vast volcanic crater. The rise on the outside of the rim is gradual, but in the inside it is almost perpendicular. As we cautiously creep to the edge, we see plumb down 15,800 feet, which is about the height of Mont Blanc above the sea. Let us take a stone—a large block can easily be lifted—and drop it over. How long it hovers in the air! It descends so slowly—six times slower than upon the earth—and it has so far to descend. Did we listen ever so long, we would hear no reverberation from that profound depth. In many places around this circular mountain wall, there are traces of terraces. In fact, the whole is a vast amphitheatre seated with terraces. In the centre of this crater a mountain rises many thousand feet in height. Let us transport ourselves to the summit; and, as you look around, you find yourself imprisoned within a perpendicular wall,
