Martino Poli is an ancient chemist despite his writing in 1706. But no ancient chemist would dare to explain Saltpeter analysis so clearly, in plain words.
Back then, analysis was not the detailed examination of an element as it is today, but rather the process of losing cohesion in a body to get magnetized, and in so doing, giving the most Secret Fire out of it (1).
Be aware that Saltpeter, potassium nitrate, was (is) a ubiquitous salt in Alchemy, and that’s for a lot of reasons which we will discover in this blog. For example, we have already learned it is helpful to lower temperatures in antimony metallurgy. But it is also employed as a Secret Fire/Mercurius source for both Mercurius Universalis, and Mercurius Crudus extracted from raw matter. Salts volatilization is involved in Mercurius Crudus to achieve a Mercurius. And analysis is not so foreign to salt volatilization. The Martino Poli separation method for saltpeter is not so different from a volatilization method. The final product could dissolve metals, indeed.
Martino Poli’s conception of analysis is ancient, of course. It dates back to a time when alchemical and chemical proceedings were not foreign to one another. Poli was an iatrochemist indeed. Let’s listen to him (my translation from Italian):
“Chemistry is experimental philosophy, true imitation of nature, by which, analyzing all the natural mixed, chemists separate from them the true principles that, once purified and exalted, are reunified again.”
Il Trionfo degli Acidi, or the Triumph of Acids, was conceived by Martino Poli as a pamphlet against the modern chemistry theories that were already around at the beginning of the eighteenth century. From Poli’s introduction:
“Moderns write more clearly since they compare the physical system to the clocks’ mechanical structure and other artificial machines rather than elucidating the principles of natural things, which they have buried. They named their new philosophy mechanical and corpuscular”.
Nevertheless, Poli is a man of his time when speaking with a clarity that would have been unthinkable a century earlier. But it is fair to say that if old ideas were satisfactory, they would not have been replaced by new ones. Ancient science is well suited to alchemy, not science. Relying on Mercurius Philosophorum for treating diseases would be unwarranted for practical and confidentiality reasons. Human medicine and science must follow their way of continuous progress. And to be honest, Alchemy, too, should modernize its means.
Il Trionfo degli Acidi, page 27: “Take of refined saltpeter reduced in very sharp crystals through repeated solutions and coagulation, in such a way to observe its pyramidal shape without a microscope. Join together with the double weight of Armenian bole (2) and put the whole to distill in a luted retort providing a large container, and graduate fire according to the art, it draws a spirit of great utility, which corrected several times only by itself, was found to be a pure and fine spirit stripped of its original shape so that when observed under a microscope
you will not see anything”.
In the Martino Poli method, we do not have a liquid to vaporize but to remove a volatile constituent of a mixture by using heat. Compare with other salts’ volatilization systems, for example, with Starkey’s volatilization of alkalis. Saltpeter/potassium nitrate was considered an alkali back at that time. Or a substance not so different from Tartar.
“The saltpeter so treated shall be operational and suitable for dissolving all metals and other rigid bodies, and if you analyze a caput mortuum, dissolve it into the water, and get it evaporated, you can extract a fixed terrestrial salt which in the same way lacks the form of saltpeter, but it acquires an irregular another one, as it is with fixed alkali. But if you unify this salt to its spirit, it produces a snapshot of fermentation, which, once stopped, can show again its spirit covered by its body in the form of a pyramid acute salt as before distillation. But in this state, it is not operative at all nor penetrates the metal in any way. From this, we understand that spirits do not operate utilizing their shape, which on the other hand, they do not have, but rather through their subtlety. In chemical analysis, fire does not alter principles but only disintegrates them because otherwise, as we gather them together, they will no longer form the same compound but a different pattern.
For example, even if taking Roman or Hungarian vitriol (3), which has a hexagonal form in its embodiment, and distilling it alone without any addition into a well-luted retort provided with a wide container and giving it a graded fire according to the art, at the beginning one can extract tasteless water and then, utilizing a mighty fire, it yields a very acid spirit which, if rectified in the same way, becomes clear and when observed under a microscope shows no shape. It is suitable to dissolve many hard and compact bodies in this state. There is rough and irregular red earth in the caput mortuum or sediments left on the retort bottom. Still, if you reunify the spirit to its caput mortuum and then dissolve it in water, filtered and evaporated, you can observe vitriol growing again in hexagonal shape, as it was before. The same happens with wine tartar, alum, and other salts, usually in a precise shape”.
Martino Poli believes that a particular mixed spirit or soul is responsible for form, color, and flavor. A conviction that no longer belongs to modern alchemists, though it cannot be considered harmful. Poli, furthermore, does not draw a line between acid vapors and spirits. In fact, like many other baroque period chemists, he gives credence that whatsoever vapor may be, or at least has a lot to do with a spirit.
“From that, one gets a double consequence. The first is that fire cannot in any way change principles, though it separates their parties. The second is that the first components have no specific shape, but joined together, they make countless shapes and can determine how many there are of them in nature. At the same time, the Supreme Factor in the making of the world created matter first and then endowed it with various forms, as one can note in the specification of all things and the creation of man. The corporeal matter is earth equipped with a double form, that’s to say, interior and exterior. The inner one was the spiracle of life, namely the soul, which is the body’s first formal institution. In contrast, the outer one is the distribution of organic parts and serves as a vessel or servile instrument for the soul and spirits. So it is an illusion that our body may function according to the mechanics of watches, as affirmed by moderns”.
For an exhaustive treatise on Saltpeter, see Lemery, Saltpeter & the Blood of Salamander.
- See an Opus Magnum scheme;
- Bolus or bole, from Greek bolos or clod. In iatrochemistry, it was a large and pulpy pill. Mineralogy was a generic term to define clay mixtures. Armenian bole was a mixture of fine, compact, earthy clay and albumen employed as a foundation for gold foils to be applied. In this Martino Poli excerpt, bole was to prevent saltpeter from aggregating since distillation of a large aggregate becomes quite impossible;
- For Hungarian vitriol see also Weidenfeld & Basilius Valentinus Oleum Vitriolis;