which fades from the soft lake and gliding river is sealed, to all eternity, upon the rock; and while things that pass visibly from birth to death may sometimes forget their feebleness, the mountains are made to possess a perpetual memorial of their infancy,--that infancy which the prophet saw in his vision: "I beheld the earth, and lo, it was without form and void, and the heavens, and they had no light. I beheld the mountains, and lo, they _trembled_; and all the hills _moved lightly_." Serviceable characters of the Slaty Crystallines. 1. Fitness for building with. Sec. 7. Thus far may we trace the apparent typical signification of the structure of those noble rocks. The material uses of this structure are not less important. These substances of the higher mountains, it is always to be remembered, were to be so hard as to enable them to be raised into, and remain in, the most magnificent forms; and this hardness renders it a matter of great difficulty for the peasant to break them into such masses as are required for his daily purposes. He is compelled in general to gather the fragments which are to form the walls of his house or his garden from the ruins into which the mountain suffers its ridges to be naturally broken; and if these pieces were absolutely irregular in shape, it would be a matter of much labor and skill to build securely with them. But the flattened arrangement of the layers of mica always causes the rock to break into flattish fragments, requiring hardly any pains in the placing them so as to lie securely in a wall, and furnishing light, broad, and unflawed pieces to serve for slates upon the roof; for fences, when set edgeways into the ground; or for pavements, when laid flat. 2. Stability in debris. Sec. 8. Farther: whenever rocks break into utterly irregular fragments, the masses of debris which they form are not only excessively difficult to walk over, but the pieces touch each other in so few points, and suffer the water to run so easily and so far through their cavities, that it takes a long series of years to enable them either to settle themselves firmly, or receive the smallest covering of vegetation. Where the substance of the stone is soft, it may soon be worn down, so that the irregular form is of less consequence. But in the hard crystallines, unless they had a tendency to break into flattish fragments, their ruin would remain for centuries in impassable desolation. The flat shape of the separate pieces prevents this; it permits--almost necessitates--their fitting into and over each other in a tolerably close mass, and thus they become comparatively easy to the foot, less permeable to water, and therefore retentive both of surface moisture and of the seeds of vegetation. 3. Security on declivities.