The Man Who Liked Books Too Much

Broadway Tower, Worcestershire.
The home of Phillipps' Middle Hill Press

In 1612, Antonio Neri published his famous book on glassmaking, L'Arte Vetraria. [1] The venture was bankrolled by Medici prince Don Antonio for whom Neri had worked as an alchemist and glassmaker in 1601 and possibly a couple of years earlier. The printer was Giunti, the venerated Florentine family of typographers who set up their first press in Venice a century and a half earlier. In Neri's era, they operated as the de facto press for the grand dukes in Florence and they are still in business today.

Neri's book was noticed almost immediately; in a 1614 letter addressed to Galileo, Roman Prince Federico Cesi practically begged his astronomer friend to send a copy. [2] Cesi was the founder of the "Accademia dei Lincei" [Society of Lynxes] a group of naturalists who formed an early version of what would later be called 'scientific societies.' The book was tailor made for such groups who were interested in performing their own experiments, however, sales did not exactly catch fire among the public. 

A few decades later, another scientific society was formed in London, with a charter signed by no less than King Charles II. The Royal Society really gave Neri's book a major boost when in 1662; founding member Robert Boyle commissioned Christopher Merrett to translate the work into English. [3] A year earlier, a second edition had been printed in Florence and a year later, another Italian edition appeared in Venice. [4]

From there, the book took off, sprouting multiple new translations in the Netherlands, Germany, France and Spain. There are many interesting stories of how the book spread across Europe; one of the most fascinating deals not with the book itself but with a publisher. Without any doubt, Sir Thomas Phillipps was the most colorful of any of Neri's printers. In 1826, Phillipps' press issued a reprint of Merrett's original English translation, which was by then over a century and a half old. [5]

By the 19th century, L'Arte Vetraria, or "The Art of Glass" as it was dubbed in English, had passed its prime as the bible of glassmakers. As one would expect, methods and technology had matured considerably over the intervening two centuries. Nevertheless, Phillipps recognized its importance. He was also a bit eccentric. As a child, by his sixth birthday, he already owned over a hundred books; his grand ambition was to own one copy of every book ever printed, a quest he carried into adulthood. He was born in Manchester, the product of a clandestine relationship between a textile baron and a woman other than the one to whom his father was married. Nevertheless, he appears to have been well cared for and inherited what Wikipedia reports was a "substantial estate." [6] A fortune that he promptly started to whittle away, spending lavishly on books and manuscripts. He attended University College Oxford and within a few years, he was made a fellow of the above-mentioned Royal Society. 

Depending on where you stand, Phillipps was a classic example of British eccentricity, a brilliant and dedicated preservationist or a completely obsessed crazy-man. Possibly all three. By the end of his life, he had amassed an estimated sixty thousand manuscripts and forty thousand books. At the time it was the largest such private collection in the world. He housed his treasure in a castle that he had built for the purpose, Broadway Tower, in Worcestershire (see photo above). It is said that he would walk into various bookstores and buy the entire stock; his agents around Europe provided a steady stream of new material. Apparently, he himself possessed a sense of humor about his odd obsession, coining the term "vello-maniac" (referring to the vellum bindings common to many books of that period).

The story does have a darker side, albeit with a silver lining. In 1842, Phillipps started collaborating in research with James Halliwell, then an undergraduate at Cambridge studying Shakespeare. Halliwell became romantically involved with Phillipps eldest daughter Harriett, but Phillipps refused consent for them to marry (which they did anyway). Meanwhile, Phillipps had run through the family fortune and started to borrow heavily. He developed paranoia against Halliwell and vowed that he would never gain control of the collection. He entered negotiations to donate the books and manuscripts to the British Library, but his conditions were unpalatable and a deal was never reached. He wanted to stipulate that the order of books should never be reshuffled and that no Roman Catholic, especially his son-in-law, ever be permitted to touch or view the collection. He became so fearful  about Halliwell that he hired 250 men to move the collection, which took two years, at which point the abandoned castle started to fall into ruins. 

In the end, Phillipps died at the age of 79 in 1872. After a court decision, Harriett did inherit her father's collection and Halliwell did gain control. The silver lining is that the two undertook to carefully disperse the collection to some of the most prestigious libraries in Europe. This project took multiple generations to finish. In fact, the final parcel of books from the Phillipps collection sold at auction in 2006, at Christie's.

[1] Neri 1612.
[2] Cesi 1614a, 1614b.
[3] Neri 1662.
[4] Neri 1661, Neri 1663.
[5] Neri 1826.
[6] "Thomas Phillipps" Wikipedia, http://en.wikipedia.org/wiki/Thomas_Phillipps 
* This post first appeared here on 5 Oct 2014.

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. Before marriage, his mother worked in an abbey hospital. Paracelsus took a degree in medicine from the university at Ferrara and proceeded to practice medicine as he wandered through Germany, France, Spain, Hungary, the Netherlands, Denmark, Sweden, Poland and Russia. 

Paracelsus died in 1541, nearly half a century before the various pamphlets he wrote started to be noticed and reprinted. In his lifetime he was not honored, but 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 gloomy but steadfast conviction that the world would shortly come to an end. Today he is celebrated for diagnoses based on careful observation of nature, and of his patients actual symptoms, a 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 the book's 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. 

Around 1600, documented in surviving letters from his friend, Emmanuel Ximenes, the two men discuss Paracelsus, but do so carefully since it is still a rather controversial topic. [6] By 1608, Neri seems a bit more relaxed, writing to a Ximenes nephew 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.

Glass Pearls

Johannes Vermeer

"Girl with a pearl earring" (1665-6)

Natural pearls, found inside various seashells, have been prized and worn as jewelry since antiquity. The pearl is formed as a secretion of the mollusk; it is the animal's response to an irritant, perhaps a sharp grain of sand, which has become lodged in its tissue. The secretion, called "nacre" is the same material from which the mollusk builds and enlarges its shell. Natural pearls are rare; large, well formed ones are even more so. A famous legend claims that Cleopatra used pearls to win a bet with Marc Antony: that she could spend ten million sesterces on a single meal. She literally drank pearls that had been ground up and dissolved in wine. Because of the difficulty in obtaining pearls, and their high demand among the wealthy, it is not surprising that like artificial gems, artificial pearls have enjoyed a brisk trade throughout history.

In Antonio Neri's era, the early seventeenth century, a number of recipes used glue, egg whites or other organic materials to simulate pearls. These had the obvious disadvantage of being susceptible to degradation by moisture and physical handling. Another alternative was to simulate pearls with glass, and on this count, Neri does not disappoint. Recipe number sixty in his 1612 book L'Arte Vetraria gives his prescription for artificial pearls. Here it is in its entirety:

In fused and clarified cristallo, add three or four portions of tartar from wine dregs. You must thoroughly calcine this tartar to a white color. Stir it thoroughly into the glass, and continue to add more tartar, also well calcined until it is white. Add four to six more portions, always stirring the glass thoroughly, continuing thus until the cristallo takes on a pearl color. In this recipe, I cannot give exact rules, because it is a matter of experience, which is gained through experimentation. Once obtained, you must work the color quickly, because it will dissipate. I have practiced and experimented with this method many times.

"Cristallo" is the exceptionally clear glass the Venetians developed, perfected and were renowned for throughout Europe. "Tartar" is a crystalline growth that forms on the inside of wine casks, what we now know as "cream of tartar." Occasionally, one might spot crystals at the bottom of bottles of wine. They are a rich source of potassium. Neri, the Venetians and others had used tartar as a glass flux over a period of centuries. Here, however, he is not using it as a flux, but as a colorant to give the glass the pearl's shimmering appearance. His claim to making many batches of this glass implies large numbers of artificial pearls were in circulation. Our glassmaker presents a second recipe, which does not make any mention of pearls, but oddly may have much more to do with the evolution of reproducing these treasures of the sea. Recipe number 114 is entitled "The Way to Tint Glass Balls, and Others Vessels of Clear Glass, From the Inside, In All Kinds of Colors, So They Will Imitate Natural Stones." Here, Neri spreads fish-glue on the inside surface of a blown globe of clear glass, followed by various pigments.

Even in his time, artificial pearls found their way into royal courts and onto the canvasses of master painters. The fashion-setting monarchs of France and Britain Catherine de' Medici and Elizabeth I were famous for their extravagant love of pearls. Elizabeth famously purchased faux pearls from Venetian glassmakers to adorn her garments. She commissioned many portraits donning her pearl studded creations. Referring to the famous painting by Johannes Vermeer, Lloyd Schwartz recently observed, "[T]he scholarship on Girl with a Pearl Earring reveals that the pearl isn't really a pearl […] the famous pearl is probably just glass painted to look like a pearl."* It is interesting to note that Vermeer's famous painting was executed in 1665-6, within five years after three reprints of Neri’s book, two in Italian one in English, and only a couple of years before a Latin edition printed in Vermeer's own country.

Around 1680, a Parisian maker of rosary beads invented a type of artificial pearl consisting of a small hollow glass bead, painted on the inside with the iridescent discharge of fish scales mixed with glue. He then filled the beads with wax. Jacquin had apparently rediscovered the shimmering pearly residue of a specific fish. His innovation fueled a new industry; he called the precious pigment "essence d'orient." But the material had already been employed in eastern France in 1656 and according to other reports as early as the reign of Henry IV of France (1572–1610), which closely coincides with Antonio Neri's own lifetime. By 1716, scientists were investigating essence d'orient under a microscope. Rene Antoine Ferchault de Reaumur reported tiny, perfectly formed rectangular plates that reflect the light to cause the shimmering.**

Perhaps more interesting than who discovered what, is the exchange of ideas and the overlap of interest between an Italian alchemist, a British queen, a Dutch painter, a French jeweler and a biologist.


* Also see Anthony Bailey, A View of Delft: Vermeer Then and Now (London: Chatto & Windus, 2001), p. 123, 124.
** For an English summary see The Edinburgh Philosophical Journal October 1839-April 1840 (Edinburgh: Adam & Charles Black, 1840), v. 28, p. 114, 115.

Fall from Grace

In 1790, two centuries after the life of glassmaker Antonio Neri, his name appeared in an unlikely place: in the annotations of a Swedish manuscript that was translated into Italian by one of Florence's leading scientists.[1] On second thought, perhaps its appearance is more unexpected than unlikely. Torbern Bergman was the celebrated Swedish chemist responsible for the manuscript and the translator was Felice Fontana, the founding director of Florence's Natural History Museum (La Specola). Fontana took the opportunity to annotate Bergman’s History of Chemistry in the Middle Ages with a list of Renaissance era materials collected in the Grand Ducal library in Florence (now the BNCF). Figuring prominently among the documents was alchemist Antonio Neri.

Below is an excerpt from one such letter, penned by Don Stefano Giraldi, the prior of San Pancrazio Church in Florence, addressed to "Your Excellency." In the passage notable characters are Don Antonio de' Medici, Neri's long-time benefactor — the prince who ran the Casino di San Marco laboratory where the priest first made glass. Also, Francesco Orlando Lorenzi (Count Lorenz, active 1793) was third count of Lorenzana and the minister of France at the Florentine court in the time of Louis XV.

Among those who abused the credulity of the Prince D[on] Antonio by leading him to understand they knew how to make gold, the most famous was Florentine Priest Antonio Neri, who, if he could not make gold, did know how to make many other beautiful and useful things, and has secured eternal fame with his work on the Art of Glassmaking, which also found prestige in the Tuscan language…  

Of other works of Preist Neri, I do not know if they have been published or even if the manuscripts have been found. Uniquely, Father Maestro Arrighi, [Augustinian] Serviette and Alchemist, in 1735 bought books that Count Lorenz had sent to France. Among them was a large manuscript in quattro by Antonio Neri. He told me that it contained a method of making the philosopher's stone and that there was a preamble  in which Neri confessed to have copied this method from a manuscript found in an old library. He  tried [the recipe] several times and always  failed.  To raise hope for others to enjoy much treasure, he had copied the method by characters in a cipher he invented and burned the old original. P[reist] Arrighi never let me see the manuscript, which was four fingers high as he assured me that the bookseller had sold it to him for the price of 5 lire; and no doubt, there will be other things besides the process of the philosopher's stone, which occupied[only a]  few page.

This flaw in Priest Neri to pass himself off as the possessor of the philosopher’s stone detracted much from his esteem. Nearby, his countrymen were wise and enlightened, and therefore he never attained the good image he should have had in his country, his mercy was the real merit of so many other good things; indeed always absent [making] gold, though he wanted to give the impression that he could, he incurred various dangers, and was forced to spend some time wandering.[2]

This gem of a letter has many interesting facets. First, it establishes that 150 years after Neri’s death, his name was still on the lips of royal courtiers and his manuscripts commanded a dear price from booksellers. It also establishes a route that his unpublished work took in leaving Italy, through France. 

The letter also provides us with insight to the changing narrative about alchemy. Neri was being distanced from the less palatable aspects of his work. "[I]f he could not make gold, [he] did know how to make many other beautiful and useful things, and has secured eternal fame with his work on the Art of Glassmaking." His sponsor Don Antonio’s portrayal as gullible about the possibility of transmutation kept the prince's reputation intact, even if somewhat diminished. (Popular history seems to have little conscience when it comes to making those who came before seem stupid.) Both Neri and Don Antonio were dedicated experimenters and they knew the proof of transmutation lay in actually making gold and they tried relentlessly. The narrative presented in the letter makes an appealing, face-saving story line, but we need only cast a sideways glance for it to start crumbling. According to the writer,  Florentines were too sophisticated to be drawn into alchemical gold-making schemes, yet a little later we find out Neri was forced to "wander" Europe, chased out of Florence by those demanding the secret of transmutation. Which was it?

The work of Neri's countryman and contemporary Galileo had established the natural sciences as Tuscany’s great patrimony. In the mid eighteenth century, when the letter was written, experimenters were as eager as ever to separate themselves from the charlatans and mountebanks who sold miracle cures and fueled impossible dreams. By then, it was agreed by researchers that transmutation was not possible, but even in the nineteenth century, there was no theoretical foundation to back up this supposition, which made it a sore point. Because of the acclaimed glass book, Neri earned a place in the pantheon of Italy's 'great men', but at a cost. His now 'embarrassing' work on transmutation caused the rest of his legacy to be largely written out of the history books.

[1] Bergman, Tofani 1790. (Fontana was writing under the pseudonym Giuseppe Tofani.)
[2] Ibid, pp. 99 - 101.
* This post first appeared here 24 December 2014.

Neri's Other Ruby Glass

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, suffice it to say that he comes 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.

The Glassmaker and the Astronomer

Portrait of Galileo Galilei, 1636 (detail),

by Justus Sustermans (1597-1681).

Galileo Galilei lived almost simultaneously with glassmaker and alchemist Antonio Neri. Both were employed by the Medici royal court in Tuscany and both spent considerable time in Florence and Pisa, possibly also in Venice and Rome. No direct contact is known to have occurred between the glassmaker and the astronomer, but their paths did cross many times, orbiting like two celestial bodies in the cosmos - albeit one with a bit more gravitas than the other. 

As a youth, Galileo was taught at the Cestello monastery by court mathematician Ostilio Ricci. This was around 1580 when Galileo was sixteen, and Neri was a four year old toddler, living only a block away and attending the Cestello church with his family. Neri's father and grandfather had just been granted citizen status, already well known for their medical prowess, and his father served on the board of the artist's guild based at Cestello. Galileo would go on to become good personal friends with Prince Don Antonio de' Medici, Neri's sponsor. Later, the astronomer would have telescope tubes made by Jacopo Ligozzi, a regular at the Casino di San Marco, where Neri worked as an alchemist and took his first steps into the craft of glassmaking. As Galileo started to experiment with lenses, Neri was leaving Italy for Antwerp and would be absent for seven years. Meanwhile Galileo landed a job at the Florentine court as mathematics tutor to Grand Duke Ferdinando's son, Cosimo II. 

Both Galileo and Neri worked hard for their achievements. In the hindsight of history, innovations are often romanticized into shining moments of inspiration, forgetting the painstaking effort and dogged persistence required to bring those ideas to fruition. For his telescopes, Galileo encountered tremendous difficulty both in the production of suitable glass and in grinding that glass into usable lenses. His celestial observations included sunspots, lunar craters and the planet Jupiter with its moons, which he named "Medicea Sideria" after his Medici benefactors. As these revelations became known, there was a clamor of orders for telescopes from princes throughout Europe and Galileo struggled to keep up. He maintained a circle of trusted craftsmen on Murano in Venice, and elsewhere, but still, the majority of output was unusable.

Initially, he had reasonable success grinding and polishing broken pieces of mirrors. In early 1610, Galileo held a demonstration in Pisa for his former pupil, Grand Duke Cosimo II. A short time later, the grand duke ordered that a special batch of glass be made for Galileo by Niccolò Sisti, for whom Antonio Neri had worked just a few years earlier. At the time, Neri himself was still in Antwerp and would not return until the following year.

Neri returned to Tuscany and wrote his book on glassmaking,  L'Arte Vetraria, but then turned his attention to other pursuits. This, just as Galileo's quest for high quality glass to make his lenses took off in earnest. Neri’s final manuscript places him in Pisa working on alchemical recipes. There was no more optimal moment for the two men to meet; both were working in Pisa, both knew Niccolò Sisti, Neri had just published his book and the astronomer was becoming desperate for clear flawless glass. If such a meeting ever occurred, it has not been recorded, and shortly thereafter, in 1614, Neri died of an unspecified illness.

On 20 December of that same year, four days before Christmas, Tommaso Caccini, Neri's childhood next-door neighbor, delivered a scathing denouncement of Galileo from the pulpit of Santa Maria Novella church. While the sermon earned Caccini a reprimand, and was an embarrassment to his family, it did also serve as a start to Galileo's troubles with the inquisition.

While Antonio Neri may have never encountered the astronomer, shortly after the time of the priest’s death, the astronomer acquired Neri's book on glassmaking. One copy was sent to Rome, to Federico Cesi, founder of the Accademia dei Lincei, a scientific society to which Galileo belonged, and another copy was saved for the astronomer's personal library. Galileo continued his quest for flawless glass and in his correspondence he takes on the same obsession with purity of ingredients that Neri exhibits throughout his book.  

* This post first appeared here in a slightly different form on 18 Novenber 2013.

Lake of Flowers

'The Miracle of the Immobility of Santa Lucia'

Leandro Bassano, using Florentine lakes.

In the final part of Antonio Neri's 1612 book on glassmaking, [1] he presents several recipes that are devoted to pigments for painting. His intention for including them is for their application on glass objects, but these were the same materials used in general by fine artists in the early seventeenth century. 

In his recipe #110, the Florentine priest gives a wonderfully simple method to extract the color from common flowers. The term for these pigments is "lakes." Once obtained, the pigments were often used to dye a powdered carrier material in order to give them more body and behave like other paint. From there they might be mixed into egg-tempera, varnish or oil depending on the application. It is likely that Neri used similar pigments for the illustrations in his 1598 manuscript.[2] Here is his recipe in its entirety: 

A Way to Extract the Lake [3] and Color for Painting, from Orange Blossoms, Red Poppies, Blue Irises, Ordinary Violets, Red Violets, Carnations, Red Roses, Borage Flowers, Day Lilies, Irises, and From Flowers of Any Desired Color and the Greens of the Mallow, the Pimpernel and All the Plants. 

Take whichever flower you want, of any color you want, or even a [green] plant. If it will rub green from a leaf onto white paper staining it with color, then it will be good. The plants and flowers that do not show this effect are no-good. Put ordinary aqua vitae into a glass urinal, with a cappello [alembic cap] for its cover, making sure the said crystallo cap is as wide as possible. 

Into this cap, pack the leaves [or petals] of any flower or plant from which you want to release and extract the tincture. Now lute the mouth joint of the cap. Fit a receiver to its snout and lute that joint. Give it a moderated fire so that the volatile part [alcohol] of the aqua vitae rises into the alembic, and falls down into its volume upon the petals of the flowers, extracting the tincture. 

In time, drops will run down the snout of the cap into the receiver, colored and charged with the tincture. Once all of the volatile part of the aqua vitae passes and becomes colored, distill this colored volatile part of the aqua vitae in a glass vessel. [The alcohol] will pass white and will be useable three more times. The dye will remain in the bottom, which you should not allow to dry too much, but just moderately. Then you will have the very best tincture or lake for painting from an abundance of flowers and plants.

The "aqua vitae" he refers to is simply a distilled alcohol such as grappa. The important point here is that it is a potent solution of ethanol and water; a well-known modern equivalent would be vodka. The chemical apparatus he describes is about as simple as it got for alchemists. It has three parts; the first is a base consisting of (in this case) a urinal—an inexpensive and convenient glass container with a wide mouth. The second piece is what Neri calls a "cappello"; it is a special glass cap featuring a long tubular snout leading from the top, angled slightly downward. When the cap is affixed to the base with the materials inside and gently heated, vapor will condense in the cap and run down the snout for collection in the third piece, a "receiver" vessel. 

The material he uses to seal the pieces together was called "lute," a mixture of mud, cloth fibers, egg and some other materials that stick to the glass and withstand the heat of the fire. Its only purpose was to keep the glassware sealed until the procedure was complete. [4] 

In the mid nineteenth century, Mary Merrifield made an extensive survey of Italian manuscripts with recipes for artists. She included this comment about Neri's home town:

Florentine lake must have had considerable reputation in Venice, since Leandro Bassano contracted to employ it in his picture of the 'Combat of the Angles,' painted for the church of S. Giorgio Maggiore at Venice in 1597. [5]

Today, this painting is known as 'The Miracle of the immobility of Santa Lucia' and is shown at the top of this post.

[1] L'Arte Vetraria, Neri 1612.
[2] Discorso, Neri 1598-1600.
[3] Neri uses the word "lacca," the equivalent of "lacha" in other manuscripts. For a specific reference to Neri in this regard, see Merrifield 1849, v. 1, p. clxxxi.
[4] A word to the wise: high proof alcohol in a confined glass container near an open flame is a good way to cause a minor explosion and a fireball featuring glass shrapnel.
[5] Merrifield 1849, v.1, p. clxxxiii. She references Cicogna  1824–1858, v. 4, p. 349 for this information. 

* This post first appeared here on 14 Oct 2014.

Descendants of a Glassmaker

Ecce Homo by Titian, circa 1570-1576

Antonio Neri was the son of a royal physician and the grandson of a well respected barber-surgeon. At the turn of the seventeenth century he pursued a career as a priest in the Catholic Church, but with the rare distinction of alchemy as his specialty. He is best remembered for his book on glassmaking, but he also wrote on the subjects of chemistry and medicine; an area of study that his family had embraced and would continue to practice  for several generations. 

According to Florentine genealogy records, Antonio's mother died in 1594, at the age of 42. She had given birth to ten children; Alessandro was the youngest, born in 1587. The same year as her death, the family would loose, Antonio's grandfather Jacopo, the barber surgeon. He had moved the family back to Florence after the turbulent 1520s; the years of what would be the final attempt to re-establish a self governing republic.  In 1598, just as Antonio finished seminary his father died leaving his ten children orphaned. A year later fifteen year old Emilio died on Christmas day.  Details of how the family survived this series of calamities may never be known, but in the end it was the youngest child, Alessandro who inherited the family house and fortune. Only eleven years old at the time of his father's death, an administrator was appointed by the court to oversee his and his siblings interests until they were of age. By all indications, the Neri children were well cared for; the list of godparents reads like a who's-who of the Florentine elite, including wealthy bankers, lawyers, senators and curia officials at the Vatican.

Alessandro would become the royal physician’s main heir. We might expect this honor to fall to the eldest son, and how the youngest of the seven brothers could end up in this position is a matter ripe for conjecture. Antonio and perhaps Francesco were in the clergy and therefore ineligible. We can surmise that the first of the sons named Jacopo died in infancy and if the second Jacopo survived he along with Vincenzio were somehow also out of consideration. One compelling scenario passes the family inheritance to fifteen-year-old Emilio, who would also die within a year leaving the mantle to Alessandro. Not yet of legal age, the family assets would have been held in trust, perhaps by his mother’s brother, notary Agostino Parenti.

Future research will likely uncover more details about the family after Antonio's death in 1614, however, a nice outline is already in place. In 1620, Alessandro inherited a second house from his uncle Agostino. It was located outside the city walls in a wealthy neighborhood, just to the southeast of Florence. It was along the old road called Via del Ponte a Ema.

In a 1630 court case in Rome, Orazio Morandi, abbot general of the Vallombrosans gave testimony. One  incidental remark he made indicates he was a Neri family friend; he told prosecutors that when he lived in Florence he often saw fellow astrologer Simon Carlo Rondinelli at the home of Alessandro de’ Neri. [1]

Although the exact date is not clear, Alessandro would marry Caterina di Becci and have three children; Neri, Dianora and Filippo. We can speculate, the first two were named after their grandparents, and the third after distant cousin Saint Philip Neri, canonized in 1622. Dianora was married to Ottaviano Buonaccorsi and had a son named Alessandro.

The bloodline would continue for another generation through Alessandro's son Neri, who would enroll in the medical program at Pisa and become a physician in his own right, taking a degree in 1646, where his diploma is still on file. [2] He in turn would marry Margherita Scalandroni who gave birth to Ottaviano. Alessandro, Francesco and Caterina.

At the end of the seventeenth century, historian Giovanni Cinelli wrote about our glassmaker’s nephew, who at the time had been practicing medicine for twenty years:

Succeeding M. Neri Neri, is a grandson [Neri di Alessandro], alive today, [1677] a man of good taste, who is delighted by pictures and sculpture, who has imitated his grandfather Neri, by [collecting] many paintings and gallant statues by talented artists. Two small bronze horses by Giambologna, many works of [Simone] Pignoni and others, among which are two marvelous holdings; a waist-up Ecce Homo by Titian and a Satyr of beautiful ancient bronze which is wonderfully captivating; it is of the Greek manner and expresses an attitude of prompt movement that recalls liveliness, the muscles are very well prepared. Finally, a statue of Cupid flanked in marble in the best Greek style. [3]

The elder Alessandro’s daughter, Dianora, would marry Ottaviano di Camillo Buonaccorsi, who gave birth to seven children. Her son named Francesco would marry into the Medici Family, coupling with Aurelia de’ Medici, daughter of Luigi di Francesco.

In 1768, historian Domenico Maria Manni wrote about the family. [4] In a short pamphlet about ancient Christian tombstones, he reports on the lineage of his patron, Girolamo Neri, a Camaldolese abbot. It traces the family back through two centuries, back to our doctor Neri Neri and to Antonio the glassmaker. Manni connects Girolamo to the family through the elder Antonio, the brother of Jacopo Neri, the barber surgeon.

Although further work is needed, all indications are that our glassmaker’s branch of the family died out by the end of the eighteenth century. [5] The family arms do not appear in use again, nor is there any evidence of a Neri tracing his heritage to the noble family of physicians. It seems finality is provided by Manni. He references a court judgment which awarded inheritance of the property of the extinct branch to Girolamo Neri’s kin. 


[1] Dooley 2002, p. 32. Dooley states that Alessandro is not related to Antonio Neri, but I feel otherwise; the name, timing, and circumstances are a perfect fit. His conclusion may be based on the scant family history available to him. Cf. ASR 1630.
[2] Mazzatinti 1917, p. 44, n. 549.
[3] Cinelli 1677. 
[4] Domenico Maria Manni, a member of the Messina scientific society known as the Accademia Pericolante. Manni was a prolific historian, although has on occasion been accused of careless work. For instance, he misidentifies Antonio’s mother as ‘Dianora di Ser Agostino di Ser Francesco Parenti’ Manni 1763, p. i-vi.
[5] Mecatti 1754, p. 77; Manni 1763, p. v.
*This post first appeared here on  29 Oct 2014.

Black is Beautiful

Black glass cameo vase, c. 1900

Thomas Webb.

Antonio Neri was a technical adept, a student of alchemical history and a glassmaker extraordinaire. He was also a gear in the early 17th century Medici innovation machine. The glass recipes he developed were likely put to work in the glass shops sponsored by the ruling family in Florence, Pisa and elsewhere. Making advances in technology gave the region a competitive advantage; encouraging the arts cemented a reputation for creativity that endures to this day throughout Tuscany.

Black is one color that has given glassmakers difficulty ever since the material's invention over four thousand years ago. It is easily approximated for large, heavy objects, but to achieve a true solid black in blown vessels, or thin layers is a challenge even for current technology.

Obsidian is a naturally occurring volcanic glass that was prized in antiquity, most often occurring in black or very dark brown. In prehistoric times, it was coveted for cutting tools and arrowheads. As technology advanced, it was ground and polished for mirrors. Later, obsidian became popular in ornamental objects ranging from dinner plates to jewelry. The production of obsidian, gemstones and other natural materials through artificial means was a quest that kept glassmakers busy.

In many ways, making black glass shows the other side of challenges in making colorless crystal; instead of a formulation that will transmit virtually all the light falling on it, the aim is to produce a glass that will absorb virtually all illumination. In his book, L' Arte Vetraria, Neri presents three recipes for "velvet black" glass (# 51-53), and three recipes for black enamel (#100-102).

His first black glass is made with the discarded broken pieces of "glass of many colors." To this, he adds 'zaffer,' a cobalt ore used to produce deep dark blue, and manganese, which produces a magenta color. He advises that it will be good for bead making cane and other work. For his second black glass, he starts with high quality frit to which he adds lead and tin oxides. This forms an opaque, white lead crystal, which he tints with calcined "steel" (probably bronze) and pulverized iron flake. He claims that after twelve hours "the glass will be a most beautiful velvety black." Neri's ultimate black glass is his simplest. He starts with his 'rocchetta' frit, and adds the dried, pulverized dregs left in red wine casks, advising us to go slowly since it froths up. He allows it to cook on the fire for four full days, and finally "washes" the glass by flinging a ladle-full at a time into clean cold water. He then re-melts it; "You will have a black fit for any job and more marvelous than all the other blacks of which I have written."

* This post first appeared here on 8 November 2013.

Neri and the Inquisition

Insignia of the Inquisition, 1574.

The mandate of the Catholic Church's inquisition was to stamp out heresy. Although empowered to impose sanctions that included torture and execution, such extreme measures were not imposed casually. Typically, they operated within communities as an extra layer of bureaucracy.  Nevertheless, the Holy Office of the Inquisition  was not an organization with which to trifle. In 1600, just over a decade before Antonio Neri's glassmaking book was printed, former Dominican friar Giordano Bruno was convicted of heresy and burned at the stake in Rome's Campo de' Fiori market, albeit after nearly a decade of confinement and numerous opportunities to recant. Shortly before that, the inquisition ordered Neapolitan polymath Giambattista della Porta to disband his group of scientific investigators and to cease all publication without special written permission from the Church, an order with which he readily complied. Famous French essayist Michel de Montaigne complained of having books confiscated upon entering Rome, although in Florence he was welcomed with open arms by Francesco de' Medici at the Casino di San Marco, where Antonio Neri would later work.

The Inquisition paid special attention to books and pamphlets because they carried the potential to 'corrupt' large numbers of people over a wide geographic area. In the Church's view, heresy was considered a disease of the mind, the devil's work. Books were seen to be a potential source to spread the infection, especially books from the Protestant quarters of Europe, but also from the 'misguided' notions of early scientific investigators. Antonio Neri was an alchemist with deep knowledge of materials that, to the unsophisticated, could easily be viewed as "magical" and therefore heretical.

The last page of Neri’s L'Arte Vetraria [The Art of Glassmaking] is devoted to the official permissions that were necessary to print and sell the book. Here we read that Pie[t]ro Niccolini, Vicar of Florence (a man destined to become the archbishop) ordered Canon Filippo del Migliore of the Florentine archdiocese to review the manuscript. Upon doing so, he found nothing that "contrasts with Christian conscience." Next, it was passed to the Holy Office of the Inquisition, where the head inquisitor of Florence, Fra Cornelio Priatoni from Manza, assigned that the manuscript be reviewed by Agostino Vigiani, Regent of Servants. Final approval came from Florentine Senator Niccolò dell’ Antella.

Within a few years, Cornelio Priatoni would  be embroiled in the investigation of Galileo. In fact, the reviewers of Neri's glass book reads like a cast of characters from the initial investigation of the famous astronomer. The Galileo case would also include Ferdinando Ximenes, the brother of Antonio Neri's good friend Emmanuel. Ferdinando was prior of Santa Maria Novella where the inquisition was based. In fact, Emmanuel's uncle, after whom he was named, also worked in the Holy Office of the Inquisition in Florence and would later give testimony in the Galileo affair.

Writing perceived to defy the Church's teaching was a serious concern for authors in Italy, even those under the protection of the liberal Medici family. Although not overtly heretical, Neri's other manuscripts could have easily fallen into this category. Thankfully for our alchemist and glassmaker, upon reading Neri's book, Vigiani stated "I have not found anything repugnant to the Christian conscience and good customs, but [a book] full of things and natural secrets, no less useful than curious." Neri's book went on to become known throughout Europe. Over the next two centuries, it was translated into English, Latin, German, French and Spanish. L'Arte Vetraria became an indispensable reference for scientific, artistic, and practical glassmakers everywhere. 

This post is based on one that originally appeared here in a slightly different form on 13 November 2013.

Pirates!

Sea fight with Barbary corsairs, c. 1581

Lorenzo Castro.

In the early seventeenth century, shipping goods and travelers around the world was big business; life on the high seas was an excellent way to find adventure, make a fortune or even become famous. On the other hand, it was also an excellent way to lose one's freedom, lose a fortune or lose one's life. International trade affected Florentine glassmaker Antonio Neri in at least two major ways; first as a consumer of exotic materials and second as a traveler. Land routes were plagued by highway robbers, corrupt officials and a host of other problems that included keeping perishables viable over long journeys, keeping pack animals in good health and navigating unreliable roads. Transport by sea promised a potentially quick journey, but at the risk of bad weather, water damage and the dreaded scourge of pirates. Aye.

In early 1604, Neri traveled to Antwerp to visit his friend Emmanuel Ximenes, who as it happens was himself an international banker; he provided the financial backing for trade expeditions to the Far East, Brazil and Africa. His extended family ran what today would be recognized as a vertically integrated corporation. The control of raw materials, to the supply chain, through to finished products was under the common management of the family. It is an open question if the Ximenes supplied Neri with materials for his work in Florence, but it is undoubtedly the case for his seven year long visit to Flanders. 

With Ximenes extensive shipping connections one might well ask why Neri did not take a boat from the Medici’s port of Livorno near Pisa, sail to one of the Spanish or Portuguese ports, where Ximenes had family and then on to Antwerp which was, after all a Spanish domain. It would be faster and one might think safer, weighed against the very real perils of violence, highway robbery and a host of other dangers when traveling by land. 

The sea route, however, was in fact far more problematic and dangerous. The Mediterranean was teeming with pirates and privateers. Privateers were state sponsored raiding parties, who commandeered the trade ships of their enemies and split their bounty with the government, often stranding the crew or selling them into slavery; it was a very lucrative enterprise, even if often short lived. Pirates, on the other hand, were independent operators, commonly they were former navy men who had lost their commission or otherwise ran afoul of their sovereigns. Basic equipment for any pirate was a chest of flags of the various nations. For any ship encountering another vessel on the high seas running under the same flag, the very first order of business was to ascertain if it was a friend as presented or a foe in disguise. An elaborate series of secret signals would follow. To complicate matters, the signals were sometimes compromised or changed without notice.  For the Spanish treasure ships returning from South America, evading pirates in the Caribbean at the start of a journey was matched by similar perils the last few days before making port in Spain. Tuscan and Venetian ships were in conflict with the Ottomans, but did conduct trade with them through intermediaries. The Dutch were undercutting Spanish deals in the Far East, while the Spanish paid cash bounties for any ship caught trading south of the equator. Meanwhile, the English were at war with the Spanish, trading with the Ottomans, but amicable with the grand duke and Tuscany.

The Barbary Coast in Tunisia, a short distance from Italy,  was a popular haven for pirates. Infamous at the time was Captain Jack Ward, [1] an Englishman who found shelter with the Ottomans through the local governor [2] to whom he paid ten percent of his bounty. Ward with his crew had converted to Islam and caused no end of grief to all European shipping. This included traders from Spain, the Netherlands, Britain, France, Tuscany and Venice. Ward had amassed a fleet of his own based on the African coast in Tunis. From here he conducted operations as far north as Ireland, running them under the Tuscan flag as well as numerous others.

Despite all these issues, for Neri, the biggest impediment by far to traveling by sea or by land was that he was heading into a war zone. Antwerp was the calm at the center of a bloody conflict that thrashed and destroyed the surrounding countryside. The Dutch fleet had blocked the city port on the Scheldt River and opposing armies clashed in a great ring around the Low Countries. This is what Emmanuel Ximenes was alluding to in his letter of December 1602 when he said “the lack of peace in these countries prevents me from recommending them for you to come or not” [3] The northern Netherlands were in the midst of a war for independence against Spain and the Holy Roman Empire.  These two superpowers of Europe were governed by the same tightly-knit Habsburg family, who at the time controlled what are now Portugal, Spain, Southern Italy and Flanders on one side of the family; Germany, Austria, Hungary and Transylvania, on the other. At the same time, the region had become a haven for formerly Jewish "New Christians" (like the Ximenes family) after their expulsion from Spain. [4] The city was blocked from sea trade by their Dutch neighbors to the north and armed confrontations with imperial troops from the south demolished surrounding towns. The conflict threatened to spill into the city for which Neri was bound.

The other way that international trade affected Neri was through the materials so necessary to glassmaking, to medicine and to his other alchemical activities. As our priest makes clear in his book, the quality of ingredients must always be tested and assayed before purchase or use. Unscrupulous merchants could and did mix or dilute expensive materials with inexpensive fillers and made unreported substitutions. The level of mistrust over imported ingredients can be better appreciated through an understanding of just how chaotic life was on the high seas. Even generally honest traders might turn to deceptive or otherwise questionable business practices when faced with the staggering losses of an entire ship and its contents. 

As the first decade of the seventeenth century unfolded, the pirating of trade ships turned into a well-organized and quite profitable occupation. Operations blanketed the entire Mediterranean and the eastern Atlantic from the Canary Islands to Ireland, which as we have seen complicated Neri’s travel arrangements in the region. Captain John (Jack) Ward was based in the Algerian and Tunisian Barbary Coast and commanded a formidable armada. Dutch born Zymen Danseker (Simon the Dancer) specialized in raiding Spanish and Portuguese trade ships. Much to Spain’s dismay, the Dutch set up outposts in India, Africa, Asia and the Americas circumventing the Habsburg’s previous monopoly.

As pirating became endemic, friction started to build between competing interests. The British and the Florentines clashed often in the Mediterranean. The grand duke employed English mercenaries to harass Turkish (Ottoman) vessels. The Ottomans were valued trading partners to the London based Levant Company. The Ottomans, upon seeing a ship manned with Englishmen, did not know whether to extend a welcome or to prepare for a fight.  Meanwhile, from his Barbary base of operations, Captain Ward continued to take British ships, strand crews and reap the rewards. All the while, he seemed to enjoy an indifferent if not outright amicable relationship with Grand Duke Ferdinando. This “understanding” developed after the sound thrashing Ward received, in 1607, at the hands of the Knights of Malta and the Knights of Saint Stephen. Once a pecking order was established with Florence, Ward did very well for himself. In June of 1608, the following description was given at court in London and then repeated to the Venetian senate through their ambassador. 

John [Jack] Ward, commonly called Captain Ward, is about 55 years of age. Very short, with little hair and that quite white; bald in front; swarthy face and beard. Speaks little and almost always swearing. Drunk from morn till night. Most prodigal and plucky. Sleeps a great deal and often on board when in port. The habits of a thorough "salt." A fool and an idiot out of his trade. [5]

This "idiot" outlived many of his detractors, evading capture and sleeping late until the ripe old age of seventy. For a man of his occupation this was a remarkable accomplishment. Reports claim he succumbed not to the sword of a British officer, but to the ravages of the plague in 1622.

[1] Jack (alias John, Birdy) Ward (c.1553–1622),Also known as Siemen Danziger, Zymen Danseker, Simon de Danser, Danziker, Dansker, Danser and later after conversion to Islam, Yusef Re’is or Reis.
[2] Uthman Bey.
[3] Ximenes 1601–11, 5 Decembre 1602.
[4] For an excellent synopsis of the historical events leading up to the 80 years war see Christman 2005.
[5] Brown 1904, (no.268 ), 23 June 1608; see also (no. 2), 6 June 1607; (no. 7), 11 June 1607; (no. 33), 21 July 1607; (no 34), 25 July 1607; (no. 112), 15 Nov 1607; (no 319), 4 September 1608.
* This post first appeared here 24 Oct 2014.

The Purse of Envy

Antonio Neri, "The Mineral Gold" Tesoro del Mondo,
(MS Ferguson 67, GB 0247,
Glasgow University Library, Special Collections,
1598-1600), f. 5r.

As a young alchemist, Antonio Neri faced a decision that had confronted virtually all accomplished artisans since the dawn of time and continues to do so today; whether or not to freely share hard-won technical knowledge with others. The indications are that Neri's thinking on the subject evolved over his lifetime. Testimony given by Florentine metals refiner Guido Melani indicate that as a twenty-year-old, Neri was willing to share his most precious secrets, albeit reluctantly.

Melani reported that in July 1596, Neri performed a transmutation of base metal into "twenty-four carat" gold. Upon being pressed, Neri confided that he had learned the secret from a German, who performed the gold transmutation with a "tablet of medicine." The German told him the medicine was nothing but the simple quintessence of green vitriol and the method to produce it was described by Paracelsus.[1] (An ion exchange reaction that we now know takes up iron and deposits copper in its place).

The motivations for keeping techniques secret are obvious; potential monetary reward and personal prestige. Aside from the immediate gratitude of confidants, the motivation for sharing technical secrets can be more subtle; the satisfaction of serving a greater good by advancing the art. It is indeed an ancient and very human dilemma. Five centuries before Neri, in the early 1100s a glassmaking Benedictine monk wrote on the subject. In Hesse, Germany, Theophilus Presbyter penned these lines in his De Diversis Artibus [On Various Arts]. "Do not hide His [God's] gifts in the purse of envy, nor conceal them in the storeroom of a selfish heart" and "Do not hide away the talent given to you by God, but, working and teaching openly and with humility, … faithfully reveal it to those who desire to learn."[2] Although it is doubtful that this particular writing was ever seen by Neri, his access to the most extensive libraries in Italy, along with his knowledge of Latin and the writings of other alchemists ensured a comprehensive understanding of his subject and the politics surrounding it.

Two centuries after Neri's death, historian Francesco Inghirami published details of an incident, which if true, might have contributed to a change of heart with our priest:

He [Neri] claimed he had found the secret of making the famous philosopher's stone and it was said he had discovered it among some of his confidants.  Some thugs learnt of this and attacked him at night, in order to obtain the secret by force. He shrewdly gave them a certain recipe he had in his pocket and explained the figures written on it, claiming it to be the secret oil required. But that night, Neri left Florence and traveled to various parts of Europe.[3]

Nevertheless, in his travels to Antwerp it is clear that Priest Neri continued to share his knowledge of glassmaking, in the shop of Filippo Gridolfi, and of course, upon his return to Florence seven years later in the publication of his famous book, L' Arte Vetraria.[4] In contrast, on the subject of transmuting gold and silver, Neri had decided to take his secrets with him to the grave, a decision that he justifies in a manuscript, Discorso, which he completed shortly before his death:

We must also consider the danger to its possessor if it became known to others and particularly to the princes. For that reason even if someone knows and practices this art, he is obliged to keep it hidden and to conceal it; and I know of what I speak.[5]

Neri outlines his fears that such a momentous discovery, if generally known could lead to abuse of power, a collapse of the monetary system, and general chaos in society. In spite of his deep reservations, we see a final glimmer of his innate desire to share. He did, in fact, leave behind his recipe for the philosopher's stone, but in coded, obscure language that has never to this day been deciphered. As he put it: "I wrote the words so strangers will not understand." 

[1]  Galluzzi 1982, p. 53; Grazzini 1983, pp. 214–216. 
[2]  For modern English translation see Theophilus 1979. 
[3]  Inghirami 1841–44, v. 13, pp. 457–458. 
[4]  Neri 1612.
[5]  Grazzini 2012, pp. 329, 356.
*This post first appeared here on 6 November 2013.