"There are seven things that can be elongated by hammering at the furnace, namely Sol, that is gold, luna (silver), tin, copper (aes), iron, lead. These are formed in nature under the earth. Gold is generated in the earth by the great heat of the sun from excellent quicksilver and red and pure sulphur by digestion in the rocks for a hundred years or more; silver from pure quicksilver and pure sulphur digested for a hundred years. But copper (...cuprum instead of aes) from impure quicksilver and impure sulphur digested for a hundred years. ...Lead, the philosophers say, is made under the earth from impure and thick quicksilver and from the worst sulphur and is a crude mixture and not well digested. And lead... renders gold breakable... Tin, however, is made from excellent and pure quicksilver, but from the poorest sulphur impure and not well digested. Iron is from thick quicksilver and thick red sulphur, and is not sufficiently digested."