There are three mercuries:
The first Mercury is the Brute Azoth, the sacred sperm. The second Mercury is sexual energy, the outcome of the transmutation of the sperm. The third Mercury is the Mercury fertilized by Sulfur; in other words, it is the sexual energy already fecundated by the sacred fire; it is a mixture of energy and fire that rises along the dorsal spine in order to take us towards the inner realization of the Being.