Metallurgy and agriculture were the two arts whose invention produced this great revolution. With the poet, it is gold and silver, but with the philosopher it is iron and corn, which have civilized men, and ruined mankind. Accordingly both one and the other were unknown to the savages of America, who for that very reason have always continued savages; nay other nations seem to have continued in a state of barbarism, as long as they continued to exercise one only of these arts without the other; and perhaps one of the best reasons that can be assigned, why Europe has been, if not earlier, at least more constantly and better civilized than the other quarters of the world, is that she both abounds most in iron and is best qualified to produce corn. It is a very difficult matter to tell how men came to know anything of iron, and the art of employing it: for we are not to suppose that they should of themselves think of digging it out of the mines, and preparing it for fusion, before they knew what could be the result of such a process. On the other hand, there is the less reason to attribute this discovery to any accidental fire, as mines are formed nowhere but in dry and barren places, and such as are bare of trees and plants, so that it looks as if nature had taken pains to keep from us so mischievous a secret. Nothing therefore remains but the extraordinary circumstance of some volcano, which, belching forth metallic substances ready fused, might have given the spectators a notion of imitating that operation of nature; and after all we must suppose them endued with an extraordinary stock of courage and foresight to undertake so painful a work, and have, at so great a distance, an eye to the advantages they might derive from it; qualities scarcely suitable but to heads more exercised, than those of such discoverers can be supposed to have been.