The first alchemists like Mary the Jewess rarely used any symbols in their writings. By the early middle-ages, that changed. Starting in the 8th century A.D., Greek alchemists were recording symbols for the 7 "planetary" metals (below). Gold (Sol) was depicted as a circle perhaps because the ancient philosophers considered the circle to be a perfect geometrical shape. Silver was related to the moon, and the moon is the oldest symbol representing the nature goddess. The waxing lunar cresent is her symbol. Other important metals in distillation are associated with the five planets known in the ancient world: copper (Venus), Iron (Mars), Lead (Saturn), tin (Jupiter), and mercury (Mercury). Each one of these symbols underwent changes over time. By the 15th century, when European alchemists were searching for the "Philosopher's Stone," these and other chemical symbols were used on a regular basis.
During the renaissance, alchemists incorporated the four elements of Aristotle into their writings where they associated them with the four stages of alchemical work. This is depicted in the drawing below. At the feet of the four alchemical sisters are the four element symbols (from left to right): earth, water, air, and fire. The four sisters are symbols for each stage of experimentation. The earth is represented by a black man or blackened metal (Maria's black) inside a flask. The "celestial" water is represented by a rose (a plant) barely visible on the chest of the man, now whitened. Gases or air are represented by a bird flying upwards. And, on the far right, fire is represented by another symbol for gold, the lion. Above each flask are the four fires of alchemical experiment.
Besides the planets, alchemists used the 12 symbols from Zodiac time. Each one represented a process in alchemical work. The alchemists combined these symbols to create a sort of shorthand. For example, the sublimate of mercury would be written as the symbol for mercury followed by the symbol for Libra or sublimation. There were also symbols for colors.
To describe actual processes during an experiment, the alchemists fell back on a biological model. To indicate adding one substance to another, they drew a man and a woman getting married or in bed together! If a new substance was created, they drew the birth of a baby. Symbols of death indicated a substance had become inactive or inert. The production of a gas was drawn as a spirit leaving a body. A precipitate was indicated by a spiritual body. A king in red represented gold and a queen in white, silver. The green lion represented mercury. A winged man-woman hermaphrodite indicated the Philosopher's Stone. These alchemical cartoons have fascinated and perplexed many a science historian. And they have created a field day for the Jungian analysts!
