Pure copper...is a soft metal and cannot be given an effective cutting edge. It is made up of layers of minute crystals; to hold the crystals together, one needs grit. Yet if one adds a particular, yet softer metal—tin—one obtains bronze; tin's impurities combine with copper to make a far stronger alloy. Much stronger, in fact: about 5 percent tin to 95 percent copper makes bronze three times as hard as the copper alone. Bronze was discovered in the Middle East around 3800 [B.C.E.] and became... "a material for all purposes, the plastic of its age."

— Richard Cohen, By The Sword, p. 110

"A professional is someone who can do his best work when he doesn't feel like it." — Alistair Cooke