ages--ever since the earth flew off from the sun, a great blot of fire, and began to cool. Then there are caverns full of water, numbing cold, fiercely hot--hotter than any boiling water. From some of these the water cannot get out, and from others it runs in channels as the blood in the body: little veins bring it down from the ice above into the great caverns of the mountain's heart, whence the arteries let it out again, gushing in pipes and clefts and ducts of all shapes and kinds, through and through its bulk, until it springs newborn to the light, and rushes down the mountain side in torrents, and down the valleys in rivers--down, down, rejoicing, to the mighty lungs of the world, that is the sea, where it is tossed in storms and cyclones, heaved up in billows, twisted in waterspouts, dashed to mist upon rocks, beaten by millions of tails, and breathed by millions of gills, whence at last, melted into vapour by the sun, it is lifted up pure into the air, and borne by the servant winds back to the mountain tops and the snow, the solid ice, and the molten stream. Well, when the heart of the earth has thus come rushing up among her children, bringing with it gifts of all that she possesses, then straightway into it rush her children to see what they can find there. With pickaxe and spade and crowbar, with boring chisel and blasting powder, they force their way back: is it to search for what toys they may have left in their long-forgotten nurseries? Hence the mountains that lift their heads into the clear air, and are dotted over with the dwellings of men, are tunnelled and bored in the darkness of their bosoms by the dwellers in the houses which they hold up to the sun and air. Curdie and his father were of these: their business was to bring to light hidden things; they sought silver in the rock and found it, and carried it out. Of the many other precious things in their mountain they knew little or nothing. Silver ore was what they were sent to find, and in darkness and danger they found it. But oh, how sweet was the air on the mountain face when they came out at sunset to go home to wife and mother! They did breathe deep then!