Morienus Romanus is the name given to a hermit who teaches King Calid in a medieval alchemical dialogue. His dates are unknown. The Paris printing of 1559 leaves little doubt about who is speaking in this passage. The teacher answers the king in the first person.
Which stone does the king need?
Morienus has just said that he knows of no other stone with quite the same effect. Asked about one particular substance, he answers in terms of the whole world. The four elements give him a way of relating something small enough to hold to the much larger order of things.[1]
For this stone contains the four elements. It resembles the world and the way the world is put together.[1]
A clue for the pupil
Calid wants to know how to proceed with his work. Colour or lustre alone would be a poor guide to the stone the teacher describes. The comparison directs the pupil to the way its ingredients fit together. That is where Morienus locates the stone’s particular value to the experiment.[1]