To appreciate the complexities of the element mercury, it is enlightening to review the role of Mercury — the god — in Greek, Roman, and Celtic mythology. Both the element and the mythological god assume complex and ever-changing forms and functions. In Greek mythology, for example, at the height of Aegean civilization around 1600 BCE, Mercury (or Hermes as the Greeks called him) was known as the god of shepherds and animal fertility (Aldington and Ames, 1968).