is first alluded to in Greek writings by Theophrastus, about 315
B.C., but it was certainly known and used medicinally by the
Chinese and in India long before. Apparently, too, it was known by the
Egyptians. Dioscorides invented the name hydrargyrum, or fluid silver,
for it. Pliny treats it as a dangerous poison. Galen adopted the
opinion that the metal is poisonous, but states that he had no personal
knowledge of its effects. With these authors argentum vivum was the
term generally used to mean the native quicksilver, while hydrargyrum
was more usually employed to describe the quicksilver obtained from the
sulphide, cinnabar. Ancient writers appear to have regarded the two
substances as distinct. Dioscorides points out that cinnabar was often
confused with minium (red lead). The name Mercury, and the association
of the metal (or demi-metal, as it was often regarded) with the planet
and with its sign, formerly associated with tin, dates from the middle
ages. It is mentioned first in this connection in a list of metals by
Stephanus of Alexandria, in the seventh century.
[Illustration]