An alchemist will frequently use this technique, also known as circulation, to cause the distillate to be recombined repeatedly with the base matter. The distillate rises, condenses, and falls back into the boiling flask, and this is done in order to cause more of the essence to be separated. In alchemical tincturing, cohobation is also used in order to further determine (imprint) the Sulfur onto the Mercury.
The question sometimes arises as to the difference between the seven alchemical steps (procedures) revealed in the Emerald Tablet, versus the twelve steps inferred by adepts such as Basil Valentine and George Ripley. Are these 12 operations in the twelve step process included within the seven steps, are they really two separate systems?
The seven-step tradition (which dates back to the Emerald Tablet) consolidates several steps together. For instance, the operation of Putrefaction is a preliminary stage to Fermentation (or Digestion); Cibation (or adding moisture at just the right moment) is part of the Dissolution process; Amalgamation is a metallic Conjunctio; Cohobation and Sublimation are usually associated with the more generalized process called Distillation; while Projection and Multiplication are most often associated with Coagulation.
As for the twelve signs of the zodiac, the following associations have been made by alchemists:
Calcination - Aries (sometimes Sagittarius); Dissolution - Cancer; Separation - Scorpio (and sometimes Sagittarius); Conjunction - Taurus; Fermentation - Leo and Capricorn; Distillation - Virgo and Libra; Coagulation - Gemini, Pisces, and Aquarius.