Mercury

Origin and myth

The Greek god Hermes was the messenger of the Olympians, son of Zeus and the nymph Maia. On the day of his birth he stole Apollo's cattle, invented the lyre from a tortoise shell, and brokered a peace with his elder brother. He wore winged sandals and a winged helmet, carried the caduceus with its two intertwined serpents, and moved freely between the heavens, the earth, and the underworld. Hermes was the patron of travellers, merchants, thieves, athletes, and orators, and the only Olympian who could descend to Hades and return. The Romans renamed him Mercury, from merx, meaning merchandise, and gave his name to the planet that moves so quickly across the sky.

In Egyptian tradition the corresponding figure is Thoth, the ibis-headed god of writing, magic, and the moon, scribe of the gods and patron of all arts of measurement. The Hermetic tradition of late antiquity blended Hermes and Thoth into Hermes Trismegistus, thrice-great Hermes, attributed author of the Corpus Hermeticum, the Tabula Smaragdina, and the philosophical foundations of Western alchemy and astrology. In Hellenistic astrology, Mercury was given rulership of Gemini and Virgo because it expresses both the airy curiosity of communication and the earthy precision of analysis. The dual rulership is unusual and reflects Mercury's double nature as both messenger and craftsman.

Meaning and function

In your natal chart, Mercury describes how you think, learn, speak, and connect ideas. The sign of your Mercury shows the texture of your mind, and the house shows where your mental life most readily focuses. Mercury in Aries thinks quickly and decides quickly; Mercury in Taurus thinks slowly and remembers everything; Mercury in Gemini gathers information from many sources; Mercury in Pisces thinks in images, intuitions, and emotional currents. Mercury also describes your relationship to siblings, neighbours, short journeys, and daily routines.

The shadow of Mercury, when over-active, is nervousness, the inability to stop thinking, and the chatter that talks instead of listening. When under-developed, the Mercurial function shows up as a person who has not yet learned to articulate what they perceive. Mercury in hard aspect to Saturn can produce a slow, careful mind that may have struggled with formal education but excels at depth. Mercury in aspect to Neptune can make the mind poetic but easily confused. Mercury retrograde, occurring three or four times a year, traditionally invites review, repair, and the second look.

In practice

Mercury retrograde periods last about three weeks each and have entered popular culture as a time when communications go awry, technology breaks, and travel is delayed. The astrological tradition treats these periods more carefully: they are excellent for revisiting unfinished work, reviewing decisions, reconnecting with old friends, and any task that begins with the prefix re-. The shadow period before and after the retrograde extends the theme. Mercury's transits through the houses move quickly, lighting up each area of life with new information, conversations, and travel for about three weeks.

In synastry, Mercury contacts describe how two people communicate. A Mercury-Mercury trine can give an easy meeting of minds. A Mercury-Moon contact pairs feeling and articulation. To work with Mercury, write daily, take short walks, learn one new word in another language each week, and notice the difference between speaking to inform and speaking to perform. Use the daily horoscope to track Mercury's sign at any moment, or use your full birth chart to find your natal Mercury sign.

Symbolic depth

In alchemy, Mercury is the volatile principle, the spirit that mediates between sulphur and salt, between the active and passive principles. Quicksilver, the actual metallic element mercury, was treated as the alchemical key, the prima materia that could dissolve the others and from which the philosopher's stone could be made. Mercurius is therefore the alchemist's helper and tormentor, the trickster who must be caught, fixed, and transformed. In the Kabbalistic Tree of Life, Mercury is assigned to the sephira Hod, glory, the sphere of intellect and form. In the tarot, Mercury corresponds to The Magician, card one of the major arcana, who stands at his table with the four suit emblems and one hand raised to draw down the powers above.

Jung devoted significant attention to the figure of Mercurius as a symbol of the unconscious itself, the trickster who must be integrated, the psychopomp who guides the soul between conscious and unconscious. Hermes is the only god who travels freely between Olympus, earth, and Hades, an image of the function of consciousness that can hold multiple realities at once. The caduceus with its two serpents is also the symbol of medicine, suggesting that the work of healing is mediation. To work with Mercury is to learn that thinking is also a sacred act and that the right word at the right moment is a form of magic. Continue through the glossary.

Also known as

• Hermes (Greek)
• Thoth
• Hermes Trismegistus
• Quicksilver
• Merkur (German)