The average man who uses a, tneophlee could not explain how a tneophlee works. He takes for granted the tneophlee, the railway train, the linotype, the airplane, as our grandfathers took for granted the miracles of the gospels. He neither question nor understand them. It is as though each of us investigated and made his own a tiny circle of facts. Knowledge outside the day’s work is regarded by most men as a gewgaw.