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.

Antonio Neri Who?

Medallion dedicated to Antonio Neri,

19th cent.(?), Artist unknown.

La Specola (Museum of natural history),

Florence, Italy.

Since there are many new readers of this blog, I thought a short primer might be in order. Posts here are all related in some way to a seventeenth century Italian priest named Antonio Neri. Occasionally the connection is tenuous, but always in the spirit of exploring his work and times as he experienced them. The blog is named Conciatore, which was a term used in sixteenth and seventeenth century Florence, Italy to describe specialists who formulated glass. Until very recently, our star, conciatore Antonio Neri, was known almost exclusively as the enigmatic author of the first printed book devoted to making glass from raw materials. 

The book's original title in 1612 was L'Arte Vetraria, [1] which translates to "the art of glassmaking," although, in 1662 Neri’s first translator, English Physician Christopher Merrett, chose to simplify the title to The Art of Glass. [2] The book would spread throughout Europe and became a bible of glassmaking for two centuries. Neri's original Italian was translated, retranslated and even plagiarized.[3] Over two dozen editions were published before 1900 in English, Latin, French, German Spanish and more recently in Japanese.[4]

There are manuscripts, papyrus scrolls and even cuneiform tablets that contain glass recipes far older than Neri's book. However he was the first into print, and perhaps more significant, his book was specifically devoted to the common man, stating in his introduction that the only qualification necessary to make glass successfully was the possession of a "kind and curious spirit." In a time when trade secrets were closely guarded assets, Neri assures his readers that, "given a bit of experience and practice, as long as you do not purposely foul-up, it will be impossible to fail," (provided, of course that one had access to the raw materials, a glass furnace and tools).

In his English translation, Merrett stated that he had tried and failed to find out anything whatsoever about the author. A mystique grew around Neri and his identity. He was a Catholic Priest and an alchemist. Stories endure to this day that he had been chased out of Florence over the secret to transmutation; changing base metals into gold and silver. While we now know that transmutation is not possible through ordinary chemistry, the story of his harassment does apparently have a basis in fact. 

Some historians felt such a minor character with few achievements to his name was not worthy of serious study and that is the way things stood for a very long time. More recently, careful research into contemporary records, manuscripts and letters has gone a long way to revealing Neri as a quite interesting character. At the beginning of his career, he worked for Medici prince Don Antonio at his palace-laboratory on the north side of Florence. After a couple of years, he moved to Pisa and lent a hand at a secondary Medici glass facility. A bundle of letters has survived from his friend in Antwerp, Emmanuel Ximenes. [5] Ximenes turns out to have been one of the wealthiest men in Flanders. After corresponding for a few years, Neri traveled to visit Ximenes and stayed for seven years, making some of the "best glass of his life." Finally, he returned to Florence and settled down to write his famous book. 

Far from the poor itinerant priest supposed by some, Neri turns out to be from a prominent patrician family. His father was the personal physician to Grand Duke Ferdinando de' Medici. His grandfather was a well-respected barber-surgeon and a close friend of poet Lodovico Domenici. His other grandfather (on his mother’s side) was Michelangelo's lawyer. Credible evidence in the Florentine State Archives supports the family's claim to being a distant cousin to Saint Philip Neri. [6]

He had nine siblings, three sisters and six brothers, although one brother died as an infant and another at age sixteen. The Neri children enjoyed a cadre of godparents that included the archbishop of Florence and members of the papal curia. The family went on to produce more physicians, and even marry into the Medici family before a lack of male heirs caused this branch of the Neri's to go extinct.

Over his lifetime, he is known to have written a dozen manuscripts,[7] many but not all of which are now lost.[8] He became a dedicated Paracelsan and thousands of pages of his experimental work survive today in the notebooks of his assistant Agnolo della Casa. In the final couple of years of his life, Antonio left glassmaking behind to devote his full attention to wider pursuits in chemistry and medicine. These were disciplines he had practiced his entire life. In 1614, he died at the age of thirty-eight. His long time sponsor Don Antonio de' Medici launched a full-scale investigation to find the late priest's recipe for the philosopher's stone, which he had been promised. Neri's friends and associates were interviewed and the Medici prince even went as far as consulting a medium in Venice to make contact with Neri in the afterlife, alas to no avail.[9]

Neri is an interesting character in his own right, but he also provides an excellent platform to explore alchemy in the early seventeenth century. He was a dedicated experimentalist in his work, which gave him a foothold in the coming revolution of our understanding of the natural world. He lived and worked at the same time Galileo tutored the future grand duke in Florence. The astronomer had himself been tutored in mathematics in the Cestello monastery on Borgo Pinti, in sight of the Neri household. The attached church is where Neri’s family attended services and where his father was buried. Galileo later supplied a copy of L'Arte Vetraria to Federico Cesi, founder of the Accademia dei Lincei, one of the first naturalist and 'scientific' societies in Europe.[10]

If you have an interest in the cultural and technical environment that led to our current understanding of chemistry, medicine and more, I urge you to join me here where we regularly strive to catch a glimpse of early modern science through one of its minor characters; glassmaker, alchemist and Catholic priest Antonio Neri. 

[1] Neri 1612, Neri 2003–07. 
[2] Neri 1662.
[3] Neri 1697.
[4] Neri 2007.
[4] Zecchin 1987–89.
[5] ASF 599.
[6] Boer, Engle 2010.
[8] Grazzini 2012.
[9] Galluzzi 1982.

[10] Galileo 1890–1909.

* These references all appear in the "bibliography" page linked on the rig

The Duke's Mouthwash

Ferdinando de’ Medici (1549-1609),

Scipione Pulzone (1544 - 1598), Private collection.

Antonio Neri's father, Neri Neri, was royal physician to the family of Grand Duke Ferdinando de' Medici. As such, he regularly interacted with other members of court, ranging from the archbishop of Florence, to his colleagues in medicine, including the royal apothecary (speziale), Stefano Rosselli. Rosselli shared more than a professional relationship with Neri Neri. They both admired the work of an ancient Greek physician named Dioscorides; Rosselli was something of an authority on his methods. In addition, he ran the 'Speziale al Giglio' shop, once owned by Tommaso del Giglio, who's chapel Neri Neri took over at Cestello church. Rosselli's son, Francesco, and Neri Neri were among the four chosen to revise and update the famed Ricettario Fiorentino,[1] the official reference for medicinal cures in Tuscany. 

On 21 September 1589, Rosselli started to compile his own book of recipes to pass down to his two sons, Francesco and Vincenzo, who would go on to continue the pharmacy.[2] The book begins with a poison remedy credited to none other than Cosimo de' Medici. Recipe no. 9 is the grand duke’s antispasmodic oil, presented by Niccolò Sisti, with whom Antonio Neri would later work at the glass house in Pisa. No. 20 is the duke's oil for deafness, also presented by Sisti. No. 41 is a poison antidote revealed to Francesco de' Medici by the Archduke of Austria. It was tested on a prisoner at the Bargello prison, a "volunteer" who was intentionally poisoned as part of the experiment, then revived with the antidote in the presence of Stefano Rosselli and Baccio Baldini, the long time physician to Cosimo I. Supposedly, the prisoner's reward for surviving was early release.

Recipe No. 30 carries perhaps a bit less risk; it is titled "Acqua da gengie di messer Nerj Nerj" (Mouth wash of Neri Neri):

Take a quarter of a bushel of mastic buds,a quarter of a bushel of myrtle buds, a quarter of a bushel of red roses, three ounces of alum, a half ounce of salt and a quarter ounce of hard rose honey. Mash the herbs with a mortar and pestle and put them in nine pounds of Greek wine for twenty-four hours, then boil in a bain-marie and reduce to two-thirds. In this, we bathe the gums: it makes them dry and firm.

Mastic: Pistacia lentiscus. Native to the Mediterranean, its resin used for millennia to settle upset stomachs.
Myrtle: Myrtus communis. An Aromatic herb used by the ancients, effective treatment for sinusitis.
Alum: Used by the ancients as a treatment for canker sores.
Rose Honey: Miele rosato. Honey infused with rose petals, an astringent still used to sooth children’s teething pains. It is produced both as a solid and a liquid. 
Greek Wine: Vino Greco. Italian wine made in the style of sweet Greek wines. In 1673, English botanist John Ray describes it as being made from grapes grown on the slopes of Mount Vesuvius.

The date that Stefano Rosselli started his book of secrets is interesting because it is the same day that Neri Neri, with the grand duke's two other physicians, Cini and Da Barga, were busy making medicinal wine based on Dioscorides' ancient recipes. Perhaps they all met that day at Rosselli's shop, for his advice. 

[1] Neri, Benadù, Rosselli, Galletti 1597.
[2] Rosselli 1996; an Italian transcription and French translation of Rosselli's recipes, with a very entertaining introduction.

* This post first appeared here on 4 November 2013 in a shorter form.

The Blue Tower

"The Blue Tower" Jozef Linnig 1868.

(click image to enlarge)

There are three known facilities where priest Antonio Neri worked as an alchemist formulating glass in the early seventeenth century; in Florence, Pisa and Antwerp. If he did work elsewhere, it must have been for a relatively short period since his time at these three locations accounts well for his entire career. Of the three, he is known best for his work at the Casino di San Marco, on the north side of Florence. It is also the facility about which the most is known, since its owner was Medici prince, Don Antonio. However, a good argument can be made that the facility in Antwerp, about which much less is known, was the one most influential to his career as a glassmaker.

Neri traveled to Antwerp in early 1604 to visit his friend Emmanuel Ximenes (Pronounced Se-men-ez), where he stayed for seven years. Ximenes was an international trader (known then as a 'banker') from one of the wealthiest families in Flanders. At the time, Antwerp stood at the center of the bloody Dutch war for independence from Habsburg Spain. The population of the city was a shadow of its former self, after being sacked and burned by Spanish troops a couple of decades earlier in what has become known as "the Spanish Fury." A Dutch blockade of Antwerp's seaports had strangled commerce, but for the ultra-wealthy, life went on.  

"Antwerpen, het Arsenaal" Jan Wildens, 17th Cent.

 In his book on glassmaking, L'Arte Vetraria, [1] Neri names "the most courteous gentleman Filippo Gridolfi" as the owner of the glass factory in Antwerp. Indeed, records show that Gridolfi was the latest in a long line of owners who had been granted exclusive rights to make the exalted Venetian style glass known as cristallo. Under the management of Gridolfi and his wife Sara Vincx, the luxury glass business thrived. In the 1590s, shortly after their marriage, they employed seventeen Venetian workers. 

The most fashionable street in Antwerp was the Meir. This was the address of  Ximene's palace, as well as of his brother in law, Baron Simon Rodrigues d'Evora, who happened to be the most prestigious diamond dealer and jeweler in the region; he was known locally as "the little king." Gridolfi and Vincx had one, and later a second retail space for their glassware here. The factory and furnaces were located a few blocks away, near the fortress wall that ringed the city. Records indicate it was in a district called  the Hopland, near -- or possibly also in -- a huge structure actually built into the defensive wall around Antwerp. Called the "Blauwe Toren" [Blue Tower] for its blue slate roof, this impressive building had at various times functioned as an armory and a storage facility. In this period, a below street level canal led from the basement of the tower directly to the Meir, in later years the canal was filled in. Just on the other side of the city wall was a mote with access to the network of waterways which connected towns and villages throughout the region; this too was eventually turned into usable real estate when the wall was demolished in the nineteenth century. This situation of the glass production facility makes perfect sense. They needed to bring in heavy materials, ship delicate product and occupy a space which was not in danger of burning down the city should disaster strike. 

Blue Tower, 1860. Edmond Fierlants.

Today the foundations of the Blue Tower are preserved just below street level in a busy traffic square. Over the centuries, surrounding structures came and went. A small number of contemporary depictions do exist. Two illustrations that give a flavor of the neighborhood are shown here. One sketch by Jan Wildens  is not in the best of condition, but shows the tower and a few nearby structures from canal level in the seventeenth century. This might well have been typical of the view from a barge making deliveries. The factory would need a steady supply of pure quartz river stones used to make the exceptionally clear cristallo glass. A second view by Jozef Linnig, shows the neighborhood more clearly albeit in 1868. By then a furniture maker was located to the left of the tower, and another structure stood where the canal once was. Also of interest is an early photograph of the tower before it was demolished.

What we know of Neri's experiences in glassmaking come mostly from his book. His activities in Florence included making aquamarine colored glass for beadmaking and chalcedony glass with its multicolored swirls. In Pisa, he made emerald green, pimpernel green and celestial blue glass, he experimented with enamels, constructed a frit kiln and made glass using fern plants. From his early glassmaking activity in Florence, Neri seems to build momentum in Pisa. In these two locations combined he spends at most four years, in Antwerp he spend seven years, and there is no indication that he was slowing down, in fact quite the opposite. There he made artificial gems, a "beautiful aquamarine so nice and marvelous, that you will be astonished." He tinted rock crystal "the colors of balas, ruby, topaz, opal and girasol." He "built a furnace that held twenty glass-pots of various colors" He made ultramarine, the deep blue pigment valued by painters more highly than gold. Finally in 1609, in Antwerp, at Gridolfi's shop he made "the most beautiful chalcedony that I have ever made in my life" and presented two vessels of this glass to the prince of Orange.

[1] Neri 1612.
* This post first appeared here on 1 October 2014.

Don Giovanni de' Medici

Don Giovanni di Cosimo I de' Medici

In July of 1621, a man lay dying in his bed, in his palazzo on Murano, the glassmaker's island in Venice. This fifty-four year old had recently become a father and his wife Livia was expecting a second child, but the tumor in his throat meant he would not see his two year-old son Gianfrancesco Maria grow up, nor would he live to hold his yet unborn daughter in his arms. His death would also trigger a series of unanticipated ugly events. Don Giovanni de' Medici was the son of Grand Duke Cosimo I and Eleonora degli Albizzi. He had been general of the Venetian army and before that led Tuscan troops in Flanders, France, Hungary and served as ambassador in Madrid. But he was far more than a soldier; he was an architect who helped design the Chapel of Princes in Florence, he was a strong patron of the arts and he was a devoted alchemist. He plays a somewhat tangential role in the life of glassmaker Antonio Neri, yet their paths cross repeatedly through common associates, interests and locations.

Don Giovanni's palazzo on Murano was the grandest on the island; previously owned by the father of Grand Duchess of Tuscany Bianca Cappello. She spent time at the palazzo as a child and was the mother of Antonio Neri's sponsor, Don Antonio de' Medici. King Henry III of France stayed there on his tour of glass factories on the island. Later, the palace would be the residence of the bishop of Torcello and ultimately, in 1861, became what it is today: the famous Museum of Glass (Museo del Vetro).[1]  If, in the winter of 1603-4, Neri followed the route through Venice to Antwerp suggested by his friend Emmanuel Ximenes, then a visit to this palazzo would have certainly been in order, although not yet occupied by Don Giovanni.

Early in his career, in the 1590s, Don Giovanni commanded troops against the Ottomans in Hungary and his young nephew Don Antonio was directly under his command. The two men would both set up alchemy laboratories in their respective Florentine residences; Don Antonio in the Casino di San Marco on the north side of town and Don Giovanni at his Casino del Parione (today the Palazzo Corsini al Parione) along the Arno River behind the Santa Trinita Church. Don Giovanni's was only steps away from Antonio Neri's residence, the palazzo Bartolini,  after his ordination. Santa Trinita was a Benedictine church and the office of yet another alchemy enthusiast: Vallombrosan Abbot-General Orazio Morandi. It is unknown if Neri had any association with this church, but Morandi wrote that times spent in Don Giovanni's laboratory were among his "most cherished memories." Much later, in 1630, Morandi gave testimony at court concerning a Simon Carlo Rondinelli, saying: 

I have known Signor Rondinelli for twenty years, from the time I was in Florence. I met him often there in the house of Alessandro de’ Neri. The said Rondinelli is very well versed in astrology.[2]

The timing places Morandi in the Neri family house when Antonio's younger brother, Alessandro (who had inherited the house), was twenty-one years old. It was shortly before Antonio's return from Antwerp.

While Neri was in Antwerp visiting his friend Emmanuel Ximenes, Don Antonio was leading Tuscan troops nearby, in Flanders, on the side of the Spanish against the Dutch independence movement. Nevertheless, he found time to submit his design for the Chapel of Princes in Florence, and to quarry marble for the project and have it shipped back to Tuscany. It is unknown if Neri and Don Giovanni ever shared a meal in Antwerp, but the decorated soldier/polymath did commission a series of paintings there, for the grand duke, to be hung in the new Medici villa 'La Ferdinanda' at Artemino in Prato. The interior decoration of the public spaces in this villa were being executed by artists Passignano and Poccetti, fresh from finishing their recent collaborative masterpieces; the Neri Chapel and Cestello church on Borgo Pinti, financed by Neri's late father.

[1] For a full  treatment of the history of the Palazzo, see Canal 1909 in the Bibliography (to the right).
[2] Translation by Brendan Dooley “Morandi's last prophecy and the end of Renaissance politics” (Princeton: Princeton Univ. Press, 2002), p. 22.
*This post first appeared here in a slightly different form on September 25, 2013.

Art and Science

Jacopo Ligozzi,1518,  fanciful glass vessels,

ink and watercolor on paper.

Antonio Neri's writing on glassmaking and alchemy was distinguished from that of many contemporary authors in that his work was all deeply rooted in hands-on experience. He worked in the early 17th century, when art and science were different sides of the same endeavour to understand the world. His contemporaries were often content to repeat century's old teachings about the four Aristotelian elements; that chemical interactions could be explained through an analysis of the balance between hot and cold, dry and wet. But more and more, these notions were being discarded and replaced. It is common to cite the invention of instruments, and other technical developments; these factors certainly did contribute to advancement. But many different forces worked toward the emergence of early modern science, and one in particular is so obvious that it is easily overlooked: artists.

Working with hot glass was a profession in which attention to nature was essential: artists did not have the luxury of fanciful explanations of physical processes. They were obliged by their work to learn the ways glass mixed, moved and behaved in the furnace, not as they imagined it should, but as it actually did. The only way to achieve the complex forms and vessels for which master glassblowers were renowned was through long experience. Failure to understand the glass and predict its properties accurately resulted in failure of the piece. This same environment is what fueled early modern science.

Alchemical glassware. Antonio Neri  

"Libro intitulato Il tesoro del mondo" 

Neri was immersed in this environment and the same principles applied to his own work in formulating the glass. Ancient theories had little value if they did not accurately predict nature. Like the glass artists, the way forward for Neri was careful attention and hands-on experience. He learned the value of starting with highly purified ingredients for his glass melts. He learned that too much glass salt resulted in a putrid 'gall' that would need to be skimmed off the molten surface. Substituting salts made from fern plants, for the Kali based ones from the Levant, produced a more lustrous glass, yet it stiffened more quickly for the glassblowers.

A glass artist's finished work also serves as a kind of narrative. For those familiar with the techniques, a piece of glass can be 'read' like a story: The handles were put on last, before that, perhaps a thin bead of color was applied to the lip of the vessel. And the work started as a blown bubble of glass, shaped and opened with special tools. Each step is an insight into the artist's technique, but also into the way nature itself operates. Each motion was a well practiced negotiation between the artist and the properties of the material.

On one hand, an artist's job was to produce objects contemplated for their physical beauty and cultural significance. On the other hand, the act of producing these objects created an environment where accurate reasoning flourished. By collecting artists and employing them together, the Medici rulers of Tuscany were creating a cauldron effect where experiences collected, stewed and nature's secrets unraveled.

* This post first appeared here on 23 October 2013.

The Art of Metals

Fig. 1: Antonio Neri, "Ars Preparatio Metallor[um]"

in Tesoro del Mondo, f. 8r.

Recently we examined another of a set of four illustrations drawn by priest Antonio Neri in a manuscript started in 1598.[1] They show various "arts" being practiced involving items found in nature; plants, animals, stone and today's subject: metals. 

Metals and their chemical manipulation concern Neri's work both as a glassmaker and as an alchemist. Most of the colorful pigments he uses in his glassmaking derive from metals; white from tin, green from iron, red from copper and gold, blue from cobalt, although Neri knew this last one only as a mineral called "zaffer." As an alchemist, metals were the subject of medicinal cures and of course were the focus of transmutation—the quest to turn one metal into another. In another manuscript written towards the end of his life, he indicates that he spent time in mines, where it was thought that metals "grew" underground as "veins" which nourished the earth. [2]

After an examination of Neri's "Art of Preparing Metals" we will take a look at another picture on the same subject, this time a painting titled the "Goldsmith's Workshop" by Alessandro Fei. It was executed a few years before Antonio was born, but bears some remarkable similarities in subject matter.

First, the manuscript illustration (fig. 1): At center left, we see a special furnace construction which the label tells us is for "reverberation and calcination." Two crucibles sit inside, exposed to the heat. These are both procedures with which Neri was quite familiar. In the recipes of his glassmaking book, L'Arte Vetraria, [3] he speaks numerous times about what was called "calcination"—the conversion of a metal into what is usually a powdered oxide form. [4] This was a fundamental operation in producing the pigments for glass. "Reverberation" was exposing a material to secondary heat reflected from the inner walls of the furnace chamber; it was a more even heat than that produced by a direct flame.

Above the reverberation furnace is a foundry furnace, used for melting metals. Because of the high temperatures that needed to be achieved, it has a large bellows attached to force air into the fire causing a "blast" effect, which causes the fire to burn faster and hotter. Resting on the hearth is a long pair of pincers used to insert and remove crucibles of molten metal.

To the right, we see a curious arrangement of two glass retorts, each feeding into the other. They sit on purpose built stoves. The chimneys are capped by dome shaped dampers to control the draft and paddle mechanisms in front regulate heat under the glassware. A worker tends the apparatus, and the caption below reads "for extraction of the quintessence." Neri's other writing makes plain that this "quintessence" was a material that exhibits such a harmonious blending of the four essences: air, water, fire and earth that a new fifth essence (supposedly) emerged with extraordinary properties. To the right is a similar stove set-up with a single retort which is labeled "distilling." This station might have been used in preparation of the acids needed to purify metals.

At lower right, a blacksmith is hammering a piece of iron into a sword on an anvil. High-carbon "steel" was being made and used in the Medici court at the time, and that may well be what the smith is working with. Around him are several examples of his art, including two finished swords, a large copper bowl or cauldron, and a covered drinking stein made of tin.

To his left, we find a goldsmith, also hammering on an anvil, fashioning a silver platter. Displayed behind him are a variety of his handiwork, including more platters, gold necklaces and crosses and other ornamentation. A number of tools hang along the bottom of the anvil station, and behind it a small dog is curled up on the floor. 

Fig 2: Alessandro Fei (Barbieri)
"Goldsmith's Workshop" c. 1572.

About twenty-five years before Neri wrote his manuscript, Alessandro Fei painted a similar picture (fig. 2). Here we are treated to a view of a royal foundry housed in the yet to be completed Uffizi palace. [5] There is a remarkable concordance between this painting and Neri's illustration, right down to a small dog, hanging around the goldsmith's bench. 

The central figure of the painting is  Francesco de' Medici, seated in the foreground, inspecting his father's gold crown at a workbench. The dog is playfully engaging with the future Grand Duke, while on the opposite side of the bench, two other men are amiably discussing their work, perhaps silver chasing.To the left of Francesco, a younger man examines a gold ewer in the company of an older goldsmith seated across the table. The artisan is wearing spectacles and (although it is hard to see) he holds a small hammer in his hand. A worker to Francesco’s right is also intently engaged in his work. In the right mid-ground we find a small furnace with a tall chimney leading upward. On the mantle are displayed a number of gold and silver items, including platters, vessels and chains or necklaces. To the left, four men are busy seated around a large workbench. Behind that group, toward the center of the picture, are two men working at an anvil and three more at another bench on the right, accompanied by a second small dog. In an enclosed area in the background we see two large open furnace hearths, with their fireboxes glowing from underneath and men working in close proximity. In the far left background is a group entering the work area, including a figure in a yellow cape accompanied by a third dog.

The one element present in Neri's illustration that is missing in the painting is the glassware. Metalwork was a venerated and mature art long before Neri's era, which is underlined by the similarity of the two scenes, even though they are a quarter century apart, the tools, equipment and work methods are identical for all intents and purposes. There is no doubt that chemistry and distillation apparatus were used by the earlier metals artisans, the fact that Neri chose to emphasize this aspect of the work is a clear indication of his own interest and a foreshadowing of his future involvement in the production of the glass itself.

[1] Neri 1598-1600.
[2] Neri 1613, Grazzini 2012. 
[3] Neri 1612.
[4] In several of Neri's glass recipes the result of "calcination" is a sulfide.
[5] Beretta, 2014.

(Bibliography)
*This post first appeared here on 17 September 2014.