What Is Man? and Other Essays

Old Man. What are the materials of which a steam-engine is made?
Young Man. Iron, steel, brass, white-metal, and so on.
O.M. Where are these found?
Y.M. In the rocks.
O.M. In a pure state?
Y.M. No—in ores.
O.M. Are the metals suddenly deposited in the ores?
Y.M. No—it is the patient work of countless ages.
O.M. You could make the engine out of the rocks themselves?
Y.M. Yes, a brittle one and not valuable.
O.M. You would not require much, of such an engine as that?
Y.M. No—substantially nothing.