How stars, the Moon and the search for signals shaped the ways people explain their lives.
mercurial (adj.)
Collection
The Sky Above Us
A mercurial person changes mood quickly and without warning. In the late fourteenth century the word meant “of the planet Mercury,” from Latin Mercurialis.12
Mercury was also the Roman messenger god, quick and clever, and astrology gave his qualities to those born under his planet. By the 1640s English used mercurial for a lively, quick and changeable temperament.1
The metal probably helped. Mercury, or quicksilver, stays liquid and runs at a touch, and medicine still calls anything containing it mercurial.12
His mercurial temper kept everyone guessing.