It is of two metals that exist in nature.The lead is a metal dense, heavy, of color grey bluish, whose point of fusion is of 327.5 degrees Celsius. Figuratively, the lead is a bullet or projectile.The silver is a metal precious of color white, bright, very ductile, whose point of fusion is of 960 degrees Celsius. Figuratively, the silver is money.There is a movie called silver or lead, whose name leads us to understand that failure to accept a bribe (plata or money), you will be killed (lead or bullet).