Veins of the Earth

Antonio Neri, "The Mineral Gold"
Neri 1598-2000 (Ferguson 67), f. 5r.

Over a decade before Antonio Neri wrote L’Arte Vetraria, the book on glassmaking for which he would become famous, he wrote an illustrated manuscript on the subject of alchemy. Begun around 1598 and completed in 1600, this is Neri's earliest known work, written very shortly after he was ordained as a Catholic priest. 

The illustrations are divided between technical depictions of chemical apparatus and allegorical images meant to show philosophical relationships within the natural world. Two of Neri's pictures from this latter group, respectively, show veins of gold and silver growing in the earth. The veins are depicted exactly like the arteries of an animal. In both pictures, they radiate out around fiery holes in the ground, what one might presume to be volcanos. Overhead the sun shines down on the gold and the moon over the silver. Further up in the sky, Neri shows the constellations associated with each metal; Leo the lion for gold and Cancer the crab for silver (his rendition looking more like a lobster).

It was no flight of fancy that mined metal and ore deposits were depicted as literal veins. It was widely thought these were living structures, which carried the earth’s nutrients. In one of Neri's final works, his 1613 manuscript Discorso, he explains the ancient theory that gold could occur as immature seed material, left over from the primordial creation. If properly nourished, this seed would mature and grow into the precious metal, and with the appropriate knowledge this natural process could be restarted, or accelerated and the gold could be brought to perfection by artificial means. 

Antonio Neri, "The Mineral Silver"
Neri 1598-2000 (Ferguson 67), f. 6r.

The idea that mined mineral deposits could regenerate naturally, if left to rest, is an ancient concept, one that persisted long past Neri’s era. In 1814, writing about tin mining in "On the Veins of Cornwall," William Phillips complained to the Geological Society of London, that armed with some current scientific knowledge, "nor would many miners […] believe, even to this day, in the regeneration of metals." Phillips quoted from an 1811 survey by

Tonkin, in Carew's survey of Cornwall: "Whether tin doth grow again, and fill up places which have been formerly wrought away, or whether it only seperateth itself from the consumed offal, hath been much controverted, and is not to this day decided." And  "whether—dead lodes—that have not one grain of tin in them—may not hereafter be impregnated,  matured,  and prove a future supply to the country, when the present lodes are exhausted, I think well deserves our highest consideration."  

At base, this is not superstition nor wild speculation, but rather considered judgments of thoughtful men making careful observations. Mines were often attended by acidic or other caustic liquids, either produced naturally or by washing operations, which leached out and dissolved various solubles. These liquids could sometimes dissolve metal out of ore and redeposit it elsewhere. Abandoned mines, it was noticed, could exhibit new crystal growth after a period of years or centuries. Today, the redeposition of minerals is a well accepted phenomenon, however, where it does occur it takes place not on a human time scale, but on a geological one, over millions of years.

*This post first appeared here in a slightly different form on 2 December 2013.

The Sincerest Form of Flattery

Francesco Lana Terzi (1631-1687)

Conciatore is pleased to reprise the guest-post of independent researcher Maria Grazzini. Maria is a dear friend to Conciatore. She studied Antonio Neri under the late, great Professor Paolo Rossi, philosopher and historian of science at the University of Florence. In 2012, Dr. Grazzini published an annotated English translation of Neri's manuscript in the journal Nuncius. [1] In the course of her research, she discovered a plagiarized version of the manuscript, published by the seventeenth century Jesuit polymath Francesco Lana Terzi (1631-1687). Lana Terzi is famous for his design of a "flying boat" and has been called the father of aeronautical engineering. Here is what Maria has to say on the subject in her own words:

The original was never published by Neri, perhaps due to his premature death, but even as a manuscript, it must have circulated widely. It would be interesting to know the history of its diffusion, in order to understand how it became the subject of plagiarism. Lana Terzi, well known in the Italian Academia of the late seventeenth century, published his  in 1670. [2] The entire chapter 20 is an exact reproduction of Neri's. Lana Terzi was fascinated by experimentation and manual arts. The Jesuit order refused their members permission to write about magic and alchemy; Jesuits with such esoteric interests could never write books directly devoted to these subjects, however, they could write works on the different aspects of natural philosophy. In this broader context chemical philosophy could be admitted.

Title page of Lana Terzi's Prodromo

Neri was popular in his own time for his glassmaking knowledge. His L'Arte Vetraria  was widely read and its reprints and translations appeared over the centuries. [3] Nevertheless, Neri enjoyed a considerable reputation among his contemporaries also for his 'chemical philosophy'. Discorso is a complete treatise on the subjects of chemistry and philosophy, to all appearance not different from many others written during the sixteenth century. It holds a similar structure, with an introduction defining the subject and the description of procedures. The final part lists possible objections raised against the validity of chemistry and gives Neri's timely responses. In this sense Discorso belongs to the alchemical traditions and Neri shows his deep knowledge of the Paracelsian doctrine and literature. Even so, the main features of the new 'scientific' mindset are present in Neri's treatise: the study of "the great book of nature" and the value of experimental practice. The traditional reliance on the authority of ancient wisdom loses its legitimacy. "We should not so easily give credence to all the histories," Neri claims, but we should "prove the possibility of this art of transmutation with certain […] experiences". Knowledge is acquired "with the practice of many experiences." It does not come from a divine revelation or from the study of many books.
There is no contradiction between the alchemist Neri and the glass-conciatore Neri; the will of gaining a deep knowledge of nature, based on the observation and experimentation, is common to both. Neri is always 'the technician' and never 'the philosopher'. Alchemy, the "Great Art," is the result of a deep study of nature and its aim is not to give an imitation of nature, but to make it perfect.

The 'modernity' of Neri can also be understood in his way of talking about chemical philosophy. He does not pretend to teach eternal truths, but only to indicate the way to achieve greater knowledge, by "understanding the modus operandi of nature." Consequently, the writer does not use the form of a dogmatic essay, but that of a conversational chat, or 'discourse'.

It would be interesting to discover how Lana Terzi came into possession of Neri's manuscript. Perhaps he was attracted by the mixture of old and new which was also a predominant theme of his time, when different models of knowledge coexisted and intertwined. Discorso offered him the chance of introducing the topic of alchemy without being accused of magism.

-M. G. Grazzini

[1] Grazzini 2012.
[2] Lana Terzi 1670.
[3] Neri 1612.
* This post first appeared here 29 Nov 2013.

Lead Crystal

Roemer type drinking glass c. 1677,

George Ravenscroft.

The entire fourth part of Antonio Neri's book L'Arte Vetraria is devoted to the preparation of lead glass, a forerunner of what is now commonly known as lead crystal. This section is unique in the book in that it contains the only instance of the author giving direct advice to glass artists themselves:

"To work lead glass into various drinking glasses or other vessels, or even to draw cane for beadmaking, it is necessary to raise the punty [out of the melt], and to make a gather of glass by turning. Take it out, let it cool somewhat and then work it on a well-cleaned marble [marver]. The marble should be somewhat cool, and well bathed with water before use."

He goes on to describe what might be termed a kind of dance with the glass. As with a human partner, gentle patience is required in learning the boundaries of what can and cannot be done. Ultimately, an artist must come to understand the material's behavior and personality in order to result in a great partnership. For the artist who makes unrealistic demands, glass can be a heartbreaker.  

"This sort of glass, lead glass, is so runny that were it not cooled, and taken up by turning [the punty] to wind a gather, it would be impossible to work. It is so runny that it would not even hold onto the punty, because it is as loose as soup. This arises out of [the fact that] the lead calx causes it to become very fluid."

"Namely, gather the glass little by little, allow it to cool, and work it over marble frequently bathed in water. Furthermore, make sure to keep the pot of glass rather calm, and in a place in the furnace where it will not see too much heat, otherwise it will not be possible to work this glass at all."

The formulation of lead crystal as we know it is a relatively recent development. This is a composition of crushed silica (sand or quartz), potash (potassium carbonates) and lead oxide substituting for calcium to stabilize the composition. It is also true that lead has been added to glass since its invention a few thousand years ago. It is not clear that this addition was always intentional, but a Babylonian tablet of 1700 BCE gives a recipe for pottery glaze that explicitly contains lead. At some point, a discovery showed that small amounts of lead and pigment smeared on glass and fired made stained glass paintings possible. The earliest known examples of colored stained glass windows date to 800-820 (San Vicenzo Abbey excavation in Volturno, Italy.)  In medieval Europe, leading up to Antonio Neri's time, lead glass was used in mosaic tesserae and in artificial gems.

Finally, it is worth noting that Neri's childhood church in Florence, Cestello (now called Santa Maria Maddalena dei Pazzi), was then run by Cistercian monks. It was the Cistercian luminary St. Bernard of Clairvaux who, in the twelfth century, built the first church with large windows, urging, "The soul shall seek the light by following the light."

This post first appeared here 15 November 2013.

The Paracelsans

Image of Paracelsus.

In the late sixteenth century, the writings of an obscure physician started to become very popular around Europe. Born in 1493 with the name of 
Theophrastus von Hohenheim, "Paracelsus"[1] was the son of a German physician living in Switzerland. He took a degree in medicine from the university at Ferrara and proceeded to wander through Germany, France, Spain, Hungary, the Netherlands, Denmark, Sweden, Poland and Russia. He died in 1541, nearly half a century before the various pamphlets he wrote started to be noticed and reprinted. In his lifetime he was hounded out of one European city after another for defying traditionally accepted medical practices and insisting on doing things his own way. He was known for somewhat difficult personality, and the somewhat gloomy but steadfast conviction that the world would shortly come to an end. Today he is celebrated for basing his diagnoses on a careful observation of nature, and of his patients actual symptoms, a sometimes radical departure from the norm for his time. 

By the end of the sixteenth century, his writings were being circulated among the intelligentsia of the Florentine royal court in Italy. His opinions extended not only to medicine and anatomy, but also to alchemy, botany, pharmacology, astrology, and what would later be called psychology. Paracelsus' philosophy was a powerful influence on the education of Antonio Neri in the discipline of alchemy.  Neri's father was the royal physician to Florentine Grand Duke Ferdinando de' Medici, and almost certainly did not subscribe to Paracelsan ideas, but Antonio seems to have taken a different path. His benefactor, Prince Don Antonio de' Medici was a confirmed Paracelsan.

By the time Neri's book on glassmaking appeared in 1612, the priest counted himself a devoted Paracelsan spagyricist and he as much as says so. In his introduction, he holds out the future possibility of publishing “the experience of my endeavors over many years, working in diverse parts of the world […in] the chemical and spagyric arts.” [2] Paracelsus had pioneered two new disciplines that he named "iatrochemistry" and "spagyrics." Iatrochemistry dealt with the use of minerals and chemicals in medicine; spagyrics made use of plants and their extracts. Here we get a hint that Neri's true passions lie beyond the formulation of glass. Speaking about the potential of chemistry in medicines, also in the introduction, he writes, "These are matters of nature to which I believe there is no higher calling in the service of humanity." The same techniques and terminology used to produce medical remedies shows up in Neri's glass formulations. Twice, he refers to ingredients as "medicine," [3] which he adds to the glass melt in "doses." He also uses the somewhat specialized apothecary's term 'ana', [4]  which means "in equal parts." 

Paracelsus coined the word "spagyric" in his book Liber Paragranum, [5] where he argues medicine should be based on the physical laws of nature alone. The word derives from two Greek terms: spao meaning to separate and ageiro meaning to combine. The underlying philosophy recurs throughout the history of alchemy. To enhance the special properties of a plant, break it down, to its separate constituents, then purify each and recombine them for a more potent product. Herein lay the bones of Neri’s empirical methodology with glass; one built on the processes of reduction, purification and recombination. These methods appear throughout his technical recipes. Neri utilizes the method with both plant and mineral ingredients, in the preparation of basic materials and pigments and throughout his medicinal work. You could say that these very techniques and the resultant near mania he developed for purification are responsible for the high reputation of his glass formulas. His colors were bright and clear beyond what was produced by typical preparation by artisans of his time. 

In letters from his friend Emmanuel Ximenes, around 1600 the two men discuss Paracelsus in their correspondence, but do so carefully since it is still a rather controversial topic. [6] By 1608, Neri seems a bit more relaxed, writing to a friend that he had cured diseases using the "grandissima meraviglia" (wonderfully grand) methods of Paracelsus. [7]

Mere months before his own death in 1614, Neri wrote a small tract titled Discorso. The full title translates to 'Discourse on Chemistry, what it is, and its Operations'. [8] In it, he "manifests right from the outset his adherence to the Paracelsan doctrine, which is not restricted to inorganic chemical operations involving the transmutation of metals, but has broader applicability to the field of medicine." [9] Neri begins:

The operations belonging to chemistry do not only, as some estimate, involve the transmutation of metals. It is a much more universal art, which in some ways also embraces medicine (or at least it comes very close in assisting) and it can be defined. It is an art, which resolves and reduces all ‘mixed bodies’ [corpi misti] into their primary elements, it searches out their nature and separates the pure from the impure and it makes use of the pure to perfect these bodies and even to transform one body into another. [10]

History has mostly remembered Neri as a glassmaker, but his own philosophy was a bit different. He considered himself first and foremost an alchemist and his art—the art of chemistry—was a discipline that embraced metallurgy, glassmaking and medicine. 

[1] often referred to as Philippus Aureolus Theophrastus Bombastus von Hohenheim, this concatination was not used to refer to himself. for a fascinating discussion see Thony Cristie's post here: https://thonyc.wordpress.com/2012/05/01/whats-in-a-name-2/
[2] Neri 1612, p. vii.
[3] Neri 1612, pp. 40, 104, medicina; p. 9, dose and throughout. 
[4] Neri 1612, p. 98 ana
[5]Opus Paragranum, written in 1529/30 not published until 1565. Cf. Paracelsus 1565.
[6] Neri 1980, pp. xlii–xliii, lix. In his letters, Ximenes is careful about references to Paracelsus. 
[7] Neri 1608; Zecchin 1987–89, p. 157. “… che già stava in casa il s.r. Zanobi Bartolini, che mostra gl’ effetti di mali da lui guariti secondo gli ordini Paracelsici di grandissima meraviglia…” [that previously when in the house s.r. Zanobi Bartolini showed the effects on sicknesses that he healed using the instructions of the great and marvelous Paracelsus ....].
[8] Discorso sopra la Chimica, che cosa sia, e sue Operazioni, Neri 1613.
[9] Grazzini 1983, p. 221. 
[10] For the original Italian, see Grazzini 2012.

Alchemist Cardinal

Portrait of Francesco Maria del Monte

Ottavio Leoni (1578–1630)

In the early seventeenth century, Cardinal Francesco Maria del Monte served as the unofficial Florentine cultural ambassador in Rome. He regularly entertained visiting dignitaries and represented the Medici family's interests within the Vatican. He was an avid art collector, glass enthusiast and amateur alchemist.  He was a patron to the artist Caravaggio, to the astronomer Galileo and a dear friend to Neri's employer Don Antonio de' Medici.

The strong bond of affection between Don Antonio and Cardinal Del Monte is clear from their extensive correspondence and gifts to each other.  In addition to their passion for alchemy, the two shared a strong interest in glassmaking technology. There is a chance that the cardinal met glassmaker Antonio Neri in Florence; in 1602 he visited the Casino di San Marco, where the glass foundry was located and he returned in 1608, although by then Neri was in Antwerp. Del Monte's biographer Zygmunt Waźbiński offers, "It is very likely that Cardinal Del Monte, with his interest in glass, had known then (in 1598) the [future] author [Neri] of L'Arte Vetraria." [1]

Del Monte collaborated with Niccolò Sisti, the grand duke's glass foundry master at Pisa, where Neri also worked for a time. Sisti often provided Del Monte with glassware for Medici customers within the College of Cardinals in Rome. The cardinal's patronage also brought many glassmakers in Rome to the appreciation of the papal court.  After his death, Del Monte's will shows that at his main residence, the Palazzo Madama, he maintained an entire room, "gabinetto dei vetri" [cabinet of glasswork] that housed five hundred pieces of glassware. It cannot go without mention that he was also the proud owner of what has become one of most celebrated pieces of ancient glass, now referred to as the Portland Vase.

There are indications in Neri's 1600 manuscript that he visited Rome. If so, it is hard to imagine him not seeking an audience with the cardinal, either at his villa on the Pincio,  overlooking the city or at the Palazzo Madama, now offices of the Italian Senate. The palazzo was appointed in fabulous luxury and arranged to accommodate a constant flow of dignitaries from around the world. The villa, on the other hand, was where the cardinal's alchemy laboratory was located. This was a more secluded retreat where the cardinal could entertain guests with more discretion.
   

Michelangelo Caravaggio, c. 1597
Casino Ludovisi.

As the sixteenth century ended and a new one dawned, Del Monte sheltered the rough-and-tumble painter Michelangelo Caravaggio, whom he set up with an in-house studio and an allowance. However, in 1606, the master of Realism fled Rome after reportedly murdering a tavern waiter over a tennis wager, but not before executing his only known fresco on the vaulted ceiling of Del Monte's own alchemy laboratory. Looking out over Rome, on the panoramic Pincio, in the Villa that later became the Casino Ludovisi and is now known as the Casino dell'Aurora, Caravaggio put his brush to work. 

According to Gian Pietro Bellori, the early biographer of artists, Caravaggio executed the oil painting sometime between 1597 and 1600. [2] Depicted in the mural are the three brothers Jupiter, Neptune and Pluto: the masters of the universe. The image is a double allegory of the three basic chemical substances of Paracelsus (salt sulfur and mercury) and the four Aristotelian elements (air, earth, water and fire). Jupiter with the eagle stands for sulfur and air, Neptune with the seahorse stands for mercury and water and Pluto with the three-headed dog Cerberus stands for salt and earth. Jupiter is reaching out to move the central celestial sphere in which the sun (fire) revolves around the earth. [3] 

The villa was a relatively secluded retreat where the Cardinal could entertain guests discretely, including his friend Galileo–Del Monte and his older brother Guidobaldo helped land Galileo the chair of mathematics at the university in Pisa. This is also where Galileo demonstrated his telescope for interested dignitaries in Rome. It would be interesting to hear the astronomer’s comments on Caravaggio's tribute to heliocentrism.

[1] Neri 1612.
[2] Bellori 1672, pp. 197-216.
[3] Wallach 1975, pp. 101-112.

*The material in this post first appeared in a different form on  27 Nov. 2013 and 4 Jul. 2014.

Manganese Overload

The chapel of Santa Cristina, overlooking
the valley near Monte di Voragno, in
Piedmont, Italy where manganese ore was mined
for the Venetian glass industry.

In Antonio Neri's 1612 book on glassmaking he presents a recipe for a transparent red (rubino) glass using manganese oxide as a pigment. The prescription calls for twenty ounces of colorant to each ounce of cristallo or glass. Indeed, it is an almost preposterous ratio, so let us take a closer look.

Checking the translation from Italian is the first order of business. Revisiting the original text is a simple matter, which these days is conveniently accessible online here.  On page 104 (recipe # 120) of Neri’s original 1612 edition of L’Arte Vetraria, (lines 11-12) we find: “…di questa medicina si da venti per oncia di cristallo ò vetro...”  [of this medicine will be twenty per ounce of cristallo or glass]. [1] So it seems the translation is accurate.

The second edition of Neri’s book was printed in 1661, almost fifty years after the glassmaker’s death. [2] The editor claims the correction of a number of errors, but these turn out to be mainly changes in grammatical convention; our passage is identical to the original. Likewise for Christopher Merrett’s 1662 English translation: “…there are used of this medicine 20 ounces, to one of crystall or glass…” and he makes no further comments in his observations section. So it appears for the twenty odd other editions that published over the next two centuries in Latin, German, French and Spanish.

Nevertheless, something is definitely amiss, since in his other recipes Neri always specifies the amount of glass in pounds; the only times he uses ounces are in prescriptions for artificial gems when quite small amounts of material are being prepared. Perhaps we can find a clue elsewhere in the book. In chapter 13 he describes preparing the raw manganese ore, mined in the Piedmont region of Italy. He says, “In Venice, you can always find it in abundance, since on Murano they do not use any other manganese.” For his garnet color (#47) he uses one pound of manganese to one hundred pounds of glass. For a garnet color in lead glass the ratio is 20 pounds of cristallo, 16 pounds of lead oxide, and three ounces of manganese.

Manganese oxide played and still plays a versatile role in glassmaking. In relatively small quantities it performs the role of a color neutralizer, removing the slight greenish tint introduced by iron contamination in glass. On the other extreme, it was used by Neri in conjunction with potassium carbonates and cobalt oxide to make black glass, but never in quantities more than a few percent by weight. Between the two extremes, manganese was used to make violet, wine, garnet, and amethyst colored glass. 

Judging from these other recipes and Neri’s failure to explicitly remark in this one about the outlandish ratio,  we are forced to conclude  that the twenty to one ratio of color to glass is an error that slipped through, apparently unnoticed or at least not commented upon until now. I have a fondness to gravitate to the simplest explanation, which in this case is an inadvertent reversal of the amounts; in other words the ratio should be one part pigment to twenty parts glass. Unfortunately this does not speak to why he is quoting amounts in ounces when pounds are his norm. 

As unsatisfying as it is, a well reasoned answer to this riddle does not present itself. Perhaps Neri left a clue in another of his writings. Sometimes, when we follow the facts, historical research forces us to take the most courageous stand of all: we simply do not know.

[1] Neri 1612.
[2] Neri 1661.
[3] Neri 1662.

* This post first appeared here in a slightly different form on 28 November 2014.

Neri's Other Rubino

Rhodochrosite, from the Sweet Home Mine, Colorado.

Antonio Neri is widely recognized for publishing a recipe for the coveted and difficult gold ruby glass. "Rubino" as it is sometimes called achieves a deep ruby red color utilizing only powdered metallic gold as a colorant. Perhaps because of the notoriety of that prescription, Neri’s other transparent red glass is hardly known. His recipe #120 describes a deep red pigment based on manganese. Today manganese takes its place on the periodic table as an elemental metal, but in the early seventeenth century it had not been isolated from its mineral ore. What Neri calls manganese was actually its oxide, which occurs as a black powdery material. Its effects in glass have been known since the early Egyptian dynasties and before that, as a pottery glaze. By itself the oxide produces a tint often likened to violet or amethyst. In small quantities, it is used to neutralize the slight green tint introduced by iron impurities in clear glass. 

To make his ruby red pigment, Neri starts with high quality manganese oxide from Piedmont and processes it through several alchemical operations. I will not be delving into the chemistry in detail here, but suffice it to say that he comes astoundingly close to synthesizing a highly unstable explosive, the likes of which was not "discovered" for another two centuries. It is a striking illustration of how technical ability can be in place long before theory catches up, in this case thankfully so. 

The pigment he did succeed in making is for now a mystery. Manganese carbonate, which can form ruby red crystals might fit the bill, except that it decomposes at the temperatures of molten glass. It occurs in nature as the mineral rhodochrosite as seen above. [1] Below is Neri's recipe for "Transparent Red in Glass" from his 1612 book L’Arte Vetraria. Most of the terminology is straightforward, with the exception of a few terms. 'Porphyry' is a hard granite used for grinding stones. 'Reverberation' is indirect radiation in a furnace, where the heat is reflected from the walls. 'Sublimation' is when certain materials vaporize directly from a solid form and recondense without passing through a liquid phase.

Grind manganese impalpably, then mix it with an equal amount of refined saltpeter and put it into a clay pan set to the fire, reverberating and calcining it for 24 hours. Take it then and wash its saltiness away with warm common water. Once separated from the salt, let it dry. It will be a ruby-red color. With this, mix an equal weight of sal ammoniac and grind them together over porphyry stone with distilled vinegar, which they will soak up. Leave this alone to dry and then put it in a retort with a wide body and a long neck. Heat it in sand for 12 hours to sublimate. 

Then break up the glass. Take all the deposits in the neck and body of the retort and mix it with the residual remains in the bottom. Weigh it and combine it all with as much sal ammoniac as was lost in the first sublimation. Grind everything together over the porphyry stone, with distilled vinegar for it to soak up. Then put it in a retort to sublimate as above. Repeat this sublimation, in this manner, many times until in the end, the manganese will all remain fusible in the bottom. 

This is the medicine that tints crystal and pastes in a diaphanous red color and a ruby red as well. Use 20 oz of this medicine per ounce of cristallo or glass, but more or less may be used accordingly to govern the color. The manganese should be the very best from Piedmont, so that it will have the effect of tinting the glass a beautiful ruby color and be a sight of wonderment.

[1] Manganese carbonate, MnCO3.