Letter 90 — On the Part Played by Philosophy in the Progress of Man (§12)

“And I also differ from him when he says that wise men discovered our mines of iron and copper, “when the earth, scorched by forest fires, melted the veins of ore which lay near the surface and caused the metal to gush forth.” Nay, the sort of men who discover such things are the sort of men who are busied with them.”