In the fourth chapter of his Commentary on Sendivogius Ortelius explains what to do with the previously non-filterable solids, which he will define as Caput mortuum.
If you remember, our author starts by distilling the dug up earth (apparently aged with manure) with rainwater. Then he rectified the distillation’s output, which you can find at Ortelius Commentary on Sendivogius. Chapter 3, and he ends up with the prescription: “…..From this liquor in balneum they took out a phlegm, and kept it separately. On the other hand they often distilled the spirit remaining from the earth, and also set it aside to keep”.
My translation from latin in quotation marks, my comments in regular: Theatrum Chemicum Zetzneri Argentorati, Orthelius Commentator in Novum Lumen Chymicum Michaelis Sendivogii. Chapter IV, Tome 6, page 410. Title: De extractione Salis fixi ex capite mortuo, eiusdemque resolutione in suis Spiritibus rectificatis, or On the extraction of salt fixum from caput mortuum, and additionally on the resolution of the same salt in its rectified Spirits.
Textus pergit. Postea exustos primae destillationis lapillos in mortario contusos, cum phlegmate servato, vel alia aqua communi inundarunt,………. The text goes on. They burnt the little stones of the first distillation and had them crushed in a mortar, then they flooded them with the set aside phlegm, or another common water, and only after filtration they extracted the salt fixed (sal fixum), this done, the body, terrestrial part of the same Mercurii, was perfect.
This water-liqueur prepared from the source (minera) of chalybis, called our magnet, which then will attract the celestial influence of the sun and moon, as explained in the following chapters; and with this method the crystalline dry water will be improved, which thing Sendivogius in his section “aenigma” would foreshadow as the old god Saturn of the earth.”
I transcribed the whole original latin first sentence for you to double check. In fact in the first distillation, object of the chapter two, the author did not mention the crushing of little stones in a mortar, or lapillos (little stones). He actually said that the normal praxis was about distilling from the prepared pellets but, as taken from Ortelius Commentary on Sendivogius. Chapter 2: “.….. the real philosophers, those who were adepts, modeled neither pellets nor boluses, but from the above mentioned earth they prepared lisciva, which was preceded by filtration and evaporation, at that moment, and only after they have managed to accumulate a sufficient quantity of liquor, they distilled with a proper degree of fire, and a very wild fearless owing spirit similar to sea waves finally floated on its water….” . So let’s assume he rather refers to the solid non-filterable residue remained after the filtration of the lisciva, operation which in fact can provide a certain amount of tiny gravel. ( 1).
Very likely this is what the author calls caput mortuum, which nonetheless doesn’t appear to correspond to the canonical set aside caput mortuum we are used to read about in the majority of seventeenth century treatises, i.e. usually the solid part too heavy to ascend the still. Here Ortelius makes the little stones resulting from filtration, or gravel”, to play the caput mortuum part. While canonically, and technically, this gravel would represent a mere additional “raw matter”. At this extent allow me to mention two points: first, in ancient chemistry there always were methods to “liquefy”, or bring from element earth to element water (the latter in Alchemy can correspond to the powdery form), the solid parts that could be carbonates, sulphides or little quartz. Ancient romans already knew how to make huge rocks crack with weak acids and cool-heat effect (2); secondly, we always need a terrestrial part for our alchemical Mercurii, and not only because the peculiar Secret Fire tends to be hidden in the solid substances particularly difficult to be lifted, but also because we need a certain amount of “crust”, and it is not about Mercurius and Sulfur, Sun and Moon, Spiritus Mundi and Secret Fire partnerships. We simply need a certain amount of terrestrial part which, mind you, will eventually appear in the final part of our works. If readers would find the terrestrial-celestial nomenclature a bit puzzling, they can re-read the exhaustive explication the author makes at this extent in Ortelius Commentary on Sendivogius. Preface.
So, the little tiny stones remained in the filter have to be calcined with strong fire and then crushed and ground in a mortar. The author doesn’t say if the calcined gravel has also undergone a kind of previous dissolution in cold weak acids. Anyway, those who have attentively looked at the picture have certainly noted that the mortar is kind of covered with a lid, leaving only a small hole for the pestle to go up and forth: in fact, during the first works, vapors and smokes, that’s to say the resulting gaseous parts, should not be allowed to flee but should, as much as possible, kept from flying. In fact in these volatile parts do contain many “spiritual” parts composing the best Mercurius/Dissolvent/Alkahest.
Eventually Ortelius doesn’t say if the phlegm used for the following filtration is the one that had been set aside in the rectifications following the first distillation. Anyway, having this done, he said that the body, terrestrial part of the same Mercurii, can be now called perfectly done.
The fourth chapter does not finish here, as Andreas Ortelius adds a controversial part. Controversial because of the objective difficulty found by many translators and the results achieved by the author, we do not know if ever wanted, to make things even more convoluted. If you remember, already in the first chapter (Ortelius Commentary on Sendivogius. Chapter 1), the author mentions the necessity of three salts saying they actually are a threefold salt carrying in within three salts. He describes them separately as “salt armeniac”, “nitrous” salt and “salt alkali” and just names them after their texture and/or task, independently from their chemical composition and source. We will see whether they can even descend from the same raw matter by means of different operations, or Ortelius introduces heterogeneous parts taken from another source. As for now he feels like resuming, and enlarging, the concept. But, of course, the less learned readers, at this point, could be overwhelmed by an excessive exposure to salts which doesn’t seem strictly required for the above explained process, i.e. the handling of the non-filterable solids.