One of the illustrations present in the Rosary of the Philosophers.
Illustrating has begun for the Rosary of the Philosophers and is now approximately half completed. Many of the woodcuts present show the typical Sol and Luna being combined; the process by which the philosophical (alchemical) arts are completed. The work explains that for both pure sulfur and pure mercury, the solar and lunar element are present; in sulfur the physical outward appearance is that of the sun while the inward, hidden mercurial element is its true nature, and likewise the reverse is true for pure mercury, argent vive, in which the solar element is hidden within, while it presents its lunar, silvery nature tangibly.
It should be noted that alchemy and most alchemical works (including this one) are essentially steganographies- the foliated earth so often alluded to here is nothing more than organic material (compost) that has been leeched of its saltpeter content, such that the nitrates begin accumulating as a crust upon its surface- a process in altered form used in the production of the base matter from which gunpowder was and still is made (black powder, that is.) A true alchemical secret since such acts were, in those days, little other than wizardry to most.