0.4

Metals conversely are of such density that they hardly make passage possible. A softer metal meeting a harder metal comes to be enclosed and constellated by its cutting surface; so a marble wall cuts off a greater portion of light, permitting only a faint glow to enter its veins. When a body is affected by another body its powers of activity may increase or diminish. So when a liquid part of a body meets the unmovable hardness of another body, its soft surface is impressed by certain traces of the impassable body acting upon it. If heated to the point of melting and then cooled, the metal that is more easily dilated by heat pours itself through the cracks and caves of the one that has already begun contracting. So ropes of gold are found in rivers.