Two Treatises on the Nature of the Elements and the Fifth Essence

ON THE ELEMENTS.

...no difference remains between the oil and the flame. Indeed, the oil becomes the flame, and the flame becomes the oil; the oil permeates the flame. Nevertheless, not long after, it is restored to the original form of the element by cold (which is the opposite of fire), just as I said not long ago. Therefore, anyone who ponders the nature of a flame more carefully will not only observe the reduction and restoration of the Elements to their original integrity, but also their separation from the First Matter First Matter: original "materia prima," the primeval substance from which all things were made in alchemical philosophy. This very thing surpasses all wonder and is most worthy of note. But we shall speak of these things at another time.

CHAPTER IV.

If you have properly weighed and understood those things which we related above, it is impossible that you should not perfectly know the cause of Winds, Thunder, and Lightning original: "Fulgurum," referring to the flashes of lightning specifically. Whenever the rays of the Sun penetrate and heat the air and the water without obstacle, the air [is transformed] into the nature of fire...