Think of this the next time you go through Scotland in the railway, especially when you get near Edinburgh.  As you run through the Lothians, with their noble crops of corn, and roots, and grasses—­and their great homesteads, each with its engine chimney, which makes steam do the work of men—­you will see rising out of the plain, hills of dark rock, sometimes in single knobs, like Berwick Law or Stirling Crag—­sometimes in noble ranges, like Arthur’s Seat, or the Sidlaws, or the Ochils.  Think what these black bare lumps of whinstone are, and what they do.  Remember they are mines—­not gold mines, but something richer still—­food mines, which Madam How thrust into the inside of the earth, ages and ages since, as molten lava rock, and then cooled them and lifted them up, and pared them away with her ice-plough and her rain-spade, and spread the stuff of them over the wide carses round, to make in that bleak northern climate, which once carried nothing but fir-trees and heather, a soil fit to feed a great people; to cultivate in them industry, and science, and valiant self-dependence and self-help; and to gather round the Heart of Midlothian and the Castle Rock of Edinburgh the stoutest and the ablest little nation which Lady Why has made since she made the Greeks who fought at Salamis.

Of those Greeks you have read, or ought to read, in Mr. Cox’s Tales of the Persian War.  Some day you will read of them in their own books, written in their grand old tongue.  Remember that Lady Why made them, as she has made the Scotch, by first preparing a country for them, which would call out all their courage and their skill; and then by giving them the courage and the skill to make use of the land where she had put them.

And now think what a wonderful fairy tale you might write for yourself—­and every word of it true—­of the adventures of one atom of Potash or some other Salt, no bigger than a needle’s point, in such a lava stream as I have been telling of.  How it has run round and round, and will run round age after age, in an endless chain of change.  How it began by being molten fire underground, how then it became part of a hard cold rock, lifted up into a cliff, beaten upon by rain and storm, and washed down into the soil of the plain, till, perhaps, the little atom of mineral met with the rootlet of some great tree, and was taken up into its sap in spring, through tiny veins, and hardened the next year into a piece of solid wood.  And then how that tree was cut down, and its logs, it may be, burnt upon the hearth, till the little atom of mineral lay among the wood-ashes, and was shovelled out and thrown upon the field and washed into the soil again, and taken up by the roots of a clover plant, and became an atom of vegetable matter once more.  And then how, perhaps, a rabbit came by, and ate the clover, and the grain of mineral became part of the rabbit; and then how a hawk killed that rabbit, and ate it, and so the grain became part of the hawk; and how the farmer