Of all of the multifaceted words found within alchemy, it seems that none are more commonly misunderstood than Mercury.
In the alchemical perspective, Mercury was considered the spirit of any given material. Paracelsus explained it simply as such, saying:
“For Mercury is the spirit, sulfur is the soul, and salt is the body.”
Exploration of the word spirit, featured in the article Truth of the Matter, helped to define spirit as the mind - an inherent power of consciousness. It is the part of any given material that organizes the Logos, which inherently exists within consciousness - our alchemical sulfur. To the Greeks, Logos was considered to be a divine dialogue that God had within himself. This dialogue, in effect, was the beginnings of the creation of matter and our known reality.
“In beginning was the Word, and the Word was with God, and God was the Word.” John 1:1
It is found then that Mercury is intimately tied to Sulfur - Consciousness and the mind acting as one to manifest nature. Frater Albertus pointed to this relationship, noting:
Sulfur, that is, the alchemical sulfur, is usually found in its oily form adhering to the Mercury.
Made for one another, alchemists viewed these two aspects - Sulfur and Mercury- as lovers, intimately bound together in union. These principles embodied archetypical patterns of masculinity & femininity, existing in a natural state of union unless separated by art
Mercury… Represents the feminine and passive principle. Sulfur is the…masculine or active principle
Mercury is occasionally called the Moon, the Lunar, or Diana, Sulfur is the Sun, the Solar, Apollo, the original potency, the formative principle, the active, the principle of the “invisible fire” and also of love.
These principles, being so closely tied, made it difficult at times for alchemists to distinguish between one or the other, and many times these principles were considered to be two sides of the same coin. The image of two snakes, wrapped in a circle, biting each others tails served as a symbol to describe this and helped paint a picture of the motion going on within the realm of consciousness.
Sulfur and Mercury - consciousness and Mind - existing together, naturally gave birth to the third principle - Salt.
Sulfur is the soul, the consciousness in matter. Consciousness being the actuating cause of an individual life. The Spirit is the mind, an inherent power of consciousness - this is our sulfur and mercury bound together - consciousness and mind. Consciousness, using the power of the mind, organizes and embodies thoughts, giving concrete reality to these thoughts, which have no concrete existence - it births Salt. This in turn makes all forms of matter, a matter of Soul and Spirit.