Dear Readers,

As you may have seen elsewhere, in mid February my wife and I suffered the loss of our home in a fire, in the hills of central Massachusetts. The good news is that we got out safely and had no animals in our care at the time. The fire crews were able to contain the fire from spreading, in what turned into a 3-alarm, 5-hour-long ordeal in subzero temperatures; they did amazing work, and no one was injured. The bad news is that all of my physical historical materials and research of 30 years have gone up in smoke. As a result I have decided to suspend this blog for the time being. It will remain online as a resource for those interested in the history of glass and glassmaking in the seventeenth century and beyond. I do intend to resume writing when I can, but for now my time and energy are required in getting us back on our feet.

Friends are providing temporary shelter for us nearby and our intention is to rebuild as soon as possible. To those who have reached out with a steady hand, to those who have opened their wallets, and offered advice in our time of need, we thank you from the bottom of our hearts. In what are already difficult times for all of us, you have made a huge difference in our lives.

Paul Engle
6 March, 2021

Friday, May 29, 2020

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. 

Title page of Lana Terzi's Prodromo

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.

Wednesday, May 27, 2020

A Matter of Plagiarism

Francesco Lana Terzi (1631-1687)
Conciatore is pleased to reprise the guest-post of independent researcher Maria Grazzini. Maria studied Antonio Neri under the late Professor Paolo Rossi, philosopher and historian of science at the University of Florence. In 2012, Dr. Grazzini published an annotated English translation of Neri's manuscript in the journal Nuncias. [1] In the course of her research, she discovered a plagiarized version of the manuscript, published by a famous Jesuit professor in Brescia. His version matches Neri's handwritten manuscript of 1614 word for word. Here is what Maria had to say on the subject:

The seventeenth century Jesuit scientist Francesco Lana Terzi (1631-1687) is famous for his design of a "flying boat"; he has been immortalized as the father of aeronautical engineering. What is not generally known is that he plagiarized the entire text of Antonio Neri's manuscript Discorso.

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


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

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

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

-M. G. Grazzini

[1] Grazzini 2012.
[2] Lana Terzi 1670.
[3] Neri 1612, 1613.
* this post first appeared here on 20 November 2013.

Sunday, May 24, 2020

Galleria dei Lavori

Giovanni Stradano  (Jan van der Straet) 
Alchemy Studio, 1571
(Inside the Uffizi Galleria dei Lavori)

In 1560, Cosimo I, Duke of Tuscany, commissioned Georgio Vassari to begin construction on the Uffizi Palace in Florence. Two wings of the structure frame a long, narrow courtyard leading out to banks of the Arno River. Today it houses one of Europe's premier art museums, but its original design was as the central administration of the Medici government. The lower floor held offices of the regional magistrates, and the upper floor of the west wing (above the mint) held a variety of workshops highlighting Tuscan industry. Grand Duke Cosimo de' Medici built a glass furnace there, which he staffed with Muranese masters of the art. He won their expertise through long, hard negotiations with the doge of Venice. 

A 1571 painting by Giovanni Stradano is entitled the Alchemy Studio. It shows Cosmo's son, Francesco I, in the Uffizi surrounded by laboratory equipment and workers. Under the watchful eyes of a senior alchemist, he stirs a chemical preparation over a stove with intense concentration. The prolific glassware in this scene drives home the close relationship between glassmaking and scientific investigation.

By 1588 Francesco's brother, Ferdinando I de' Medici, formally declared this space the Galleria dei Lavori or 'gallery of the works'. There is no direct evidence that Antonio Neri gained his education in alchemy at this facility, but it makes a very attractive candidate. Of note to this story is that a demonstration was performed for Ferdinando de' Medici in Rome that purported to turn half of an iron nail into gold; the work of German alchemist Leonhard Thurneysser. In the 1590s, when Neri was being schooled, several accounts describe that the nail (chiodo) remained on display for some time in the Galleria. Neri mentions the nail in his Discorso and Thurneysser is discussed in a 1601 letter to the priest from his friend Emanuel Ximenes.

After Neri's death in 1614, his Medici sponsor, don Antonio commenced a search for the glassmaker's secret of transmutation, which Neri had promised. In testimony given by a royal goldsmith, who had, in July of 1596, witnessed a demonstration in which "gold" was made by Neri, he pressed the glassmaker, who told him that the transmutation was a technique learned from a German, done with ordinary vitriol.  

It is interesting to note that when iron is soaked in a solution of "blue vitriol" now known as copper sulfate, an ion exchange reaction takes place, where the liquid deposits copper and takes up iron from the nail. It would be well into the 18th century before this chemistry was adequately understood. What the royal goldsmith would have seen is  a dull iron nail turn the color of yellow metal before their eyes. Perhaps the goldsmith was not given the opportunity to further test the sample. 

Friday, May 22, 2020

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.

Wednesday, May 20, 2020

Botanical Gardens

Rudolf  II as "Vertumnus"(c. 1590)
Giuseppe Arcimboldo.
In 1543-44 new botanical gardens were founded in Pisa; L’Orto Botanico was its Italian name. It was the very first garden devoted to the research of plants. Literally within a year, similar gardens sprung up in Padua and Florence, and many other cities followed shortly thereafter. Exotic foreign species as well as important local plants were grown, studied, harvested distilled, and imbibed. These horticultural stations became centerpieces of medical programs throughout Italy, and then greater Europe. The concept of herbal (“simples”) gardens was centuries old. Almost every monastery, convent and hospital maintained a space to grow the plants they needed to transform into medicines for care of the infirmed. The grafting of fruit trees was actively practiced since before Roman times, but these new gardens were specifically planted as research spaces and run by universities. 

When Neri Neri, the father of glassmaker Antonio Neri, studied medicine at the Studio Fiorentino  in the mid 1550s, there can be no doubt he spent time at the gardens in Florence, and quite possibly at the ones in Pisa. (The Pisa gardens were moved twice before arriving at their current location in 1591). This was a period of vigorous expansion in the field of herbal medicine. Competition was fierce to obtain and study medicinal plants from around the globe. Cosimo I de’ Medici poured money into the medical school in Pisa, attracting students and faculty from around Europe. In 1554 famed botanist and physician Andrea Cesalpino took over the Pisa gardens  from his teacher, Luca Ghini, who first built them. 

In 1602, Neri was to be found working alongside Niccolò Sisti at the grand duke’s secondary glass furnace along the Arno River in Pisa. According to Neri’s own account, Pisa is where he worked on ferns as an alternative plant salt for glass and mentions many other plants with which he experimented: 
Set about making ash in the way previously described, however use the husks and stalks of broad beans after the farmhands have thrashed and shelled them. The same may be made from the ashes of cabbages, or a thorn bush that bears small fruit, called the blackberry, even from millet, rush, marsh reeds, and from many other plants that will relinquish their salt.
In a letter to Neri from his friend Emanuel Ximenes, the Antwerp based Portuguese banker expressed surprise that Neri was able to devise a fern based glass salt recipe so quickly. In all likelihood, Neri would have had access to the botanical gardens and the small adjacent laboratory located just a few blocks from the glass furnace. In the period of time the glassmaker spent there, the directorate of the gardens changed hands from Francesco Malocchi to Marco Cornacchini. Both of these men avidly pursued new botanical based cures, and corresponded internationally. 

In his Glassmaking book, L’Arte Vetraria, Neri devotes a number of recipes to making paint pigments from flower blossoms. While he could have easily obtained his stock material from any number of sources, the botanical gardens would have certainly provided a convenient cache of many different varieties.

In the winter of 1603-4 Neri traveled From Pisa to visit his friend in Antwerp. If he followed Ximenes suggested route, he would have passed back through his native Florence, then on to Venice where he would meet up with a caravan of merchants on their way to the Frankfurt spring fair, and then on to Antwerp by river. Upon his return to Italy, seven years later, he wrote his glassmaking book, but then devoted himself fully to alchemy and medicine. In January of 1614, in what might be the very last manuscript he worked on before his death, he wrote about some recipes “copied from an old book here in Pisa.” At that time, the director of the botanical gardens was Domenico Vigna, who continued to direct the gardens on and off until 1634.

It would be interesting to know how Neri the alchemist thought about his raw materials. Did he see all the possibilities of what could be made with them? For instance, how did he approach a towering pile of May ferns, large enough to produce a hundred pounds of ash, or a giant sack of rose petals? Did he ever lean forward and breathe in the delicious musty aroma? Did he ever dig in with his hands and bury his face in an arm-load of soft, pure color? How could he not?

*This post first appeared here 22 Jan 2014.

Monday, May 18, 2020

Antonio Neri in Pisa

Majolica vase by Niccolò Sisti,
decorated in the grotesque style.
Antonio Neri's career in glassmaking took him from the city of his birth, Florence, to Pisa, Antwerp and possibly other places yet to be confirmed, such as Rome and Venice. Under the reign of Grand Duke Ferdinando de' Medici, a glass furnace at Pisa became an important source of diplomatic gifts in both glass and ceramics. Antonio Neri worked at this facility in the first years of the seventeenth century. Later, the same foundry would receive an order for exceptionally clear glass to be used by Galileo in his telescopes. It is unknown how that particular project worked out, but the furnace master, Niccolò Sisti, made a name for himself supplying glassware to the Vatican, the king of Spain and many nobles throughout Italy and Europe. Undoubtedly, Neri's glass career was strongly influenced by his tenure in Pisa with Sisti. 

In the early seventeenth century, there were several glass furnaces in Pisa. One was run at the pleasure of Grand Duke Ferdinando by Niccolò Sisti. Raised in Norcia in Perugia, he likely learned his trade at an early age;  Sisti's father, Sisto de' Bonsisti, was said to be an expert in making paste gems. This would account for the son's apparent skill in the medium of glass in addition to his ceramics prowess for which he was previously employed at the Casino di San Marco in Florence. For Neri, working at Sisti's glass house in Pisa played an important role in his glassmaking education. Sisti would serve three Medici grand dukes, Francesco I, Ferdinando I and Cosimo II. When work came to a stop at the Casino di San Marco, after Francesco’s death, Sisti may have opened his own factory in Florence for a short time, but then moved to a new facility in Pisa.

 In 1592, Grand Duke Ferdinando set up a glass shop in the central part of Pisa, along the north bank of the Arno River. This furnace was staffed by Muranese workers and was located in the city center, along the river. Archaeologists have unearthed its remains in the courtyard of what is now 43-44 Lungarno. The operation was capitalized with a loan of five hundred scudi made by Ferdinando I to Sisti, with a special mandate: he was to introduce new forms of pottery to the region. In addition to glass, the furnace at Pisa would produce soft-paste porcelain and majolica ceramics. These were both forms that Sisti had helped to develop when he worked in Florence at the Casino; he was involved in Francesco’s quest to duplicate Chinese porcelain.

In 1602, Neri was to be found working alongside Sisti at the Pisan furnace. According to his own account, this is where he worked on special colors, and collected river stones for glass frit. Here he made kermes based paints, enamels and used ferns as an alternative plant salt for glass. In all likelihood, he would have had access to the nearby botanical gardens and the small adjacent laboratory located just a few blocks from the glass furnace. 

Early in 1604, the priest would make his trip north to Antwerp to visit his friend Emmanuel Ximenes. During Neri's seven year absence, Sisti's projects included cristallo table service for the Vatican, and special glass for the lenses of Galileo's telescopes. Upon Neri's return from Flanders, we again find him working in Pisa, this time on alchemy. In a copy of his last known manuscript, a heading reads, "Techniques copied from an old book here in Pisa."  The university at Pisa was an intellectual center and a repository of technical knowledge. There, Neri had access to a wide range of materials in the libraries. The furnaces and laboratories provided him with hands-on experience, but there can be little doubt that he was a voracious reader as well. On the same page of this manuscript appears the date 26 January 1614. This is the last known specific information on the priest's whereabouts, since he would be dead within the year, at the age of thirty-eight.

*This post first appeared here in a shorter form on 18 October 2013.

Friday, May 15, 2020

True Colors

The European Roller [Pica Marina]
Antonio Neri's book, L'Arte Vetraria, is devoted to making glass from raw ingredients found in nature. Many of his finished creations were intended to also resemble the natural world. A number of colors are meant to mimic the appearance of gems and minerals, others are named after plants and animals. Some are easily recognized today, even if they are not as familiar as they were in the seventeenth century. One of his recipes will make "a wonderful pimpernel green," while others evoke peach and orange blossoms. An entire section of the book is focused on paints that are named after the flowers from which the colors are extracted. Many of these plants have remained common: poppies, irises, violets, lilies, carnations and red roses. Others are less so: the mallow, pomegranate, broom and borage flowers.

In addition to flora, the fauna make a few notable appearances in Neri's book. In chapter 16, in the preparation of iron oxide pigments, he advises that after fifteen days in the furnace, the product will be finished when it takes on the purple color of the peacock. In chapter 73 he gives a method for "tinting rock crystal the color of a viper" and chapter 121 is the method for a glass which is "red like blood."

Named in several chapters is a shade of 'celestial blue,' which Neri likens to the color of the "gazzera marina." Common bird names pose a special challenge for translation in that they, like the birds themselves, never seem to settle in space or time for very long. Vernacular names of a species can change from one century to the next, one region to another, even between adjacent valleys and several species can share the same name. It is with this admonition that we attempt to flush out the elusive gazzera marina.

Consulting a modern Italian dictionary draws the eye to the similar sounding 'gazza marina' (alca torda), known in English as the razorbill. This sea bird inhabits coastal cliffs, but alas, as a close relative of the penguin, it dons only black and white formal attire. Digging deeper we find poet Gabriele d'Annunzio, "At Dawn" carefully tracking the gazzera marina across a salty marsh, in his Halcyon. This time the poet himself throws us off the trail with his description, since no bird sports five digits but the chicken. Turning to etymology, we find another potential match in the magpie (pica pica); it is a credible but unconvincing fit with its blue and white plumage.
Aldrovandi's pica marina
Combing the references of Neri's own sixteenth century, we find the best candidate is the roller (pica marina). This bird was described by naturalist Ulisse Aldrovandi, a friend of Don Antonio de' Medici's father and guest at the Casino di San Marco, where Neri later worked. Other contemporary authors list the gazzera marina as a synonym to Aldrovandi's pica marina. Neri's Latin translator Frisius (1668) and his German translator Geissler (1678) agreed, both sighting the "Pica Marina" in their works.

This post first appeared here on 13 Sept 2013.

Wednesday, May 13, 2020

Thévenot in India

Antique gold Arsi finger ring,
 Rajasthan India.
This is the third and final installment of a series that has followed seventeenth century French tourist Jean de Thévenot from Europe to the Levant and then into Syria. Now he travels to India. We have specifically looked into his diary with an eye toward passages that mention glass or glassmaking. While our intrepid traveler had no special connection to this art, he did possess a keen, inquisitive mind; collectively, his observations about glass give us a glimpse into the state of affairs in the Middle and Far East in the mid 1600s. 


We left off with Thévenot as he headed up the Tigris River toward Baghdad, in the autumn of 1663. While he was anxious to see Mughal India, actually getting there presented some difficulty due to hostilities between the Dutch, British and Portuguese, which extended to their trade operations around the world. After a first attempt was aborted, he made a strategic retreat to Isfahan and bided some time with shorter excursions from there. Finally, in the autumn of 1665 he booked passage on the originally English ship “Hopewell” recently purchased by an Armenian trader and captained by an Italian. [1] The ship departed from Basra and made port at Surat, India in January of 1666.

The city of Agra is in the Northwestern part of India, a thousand kilometers from Surat and the coast; it is known most famously as the home the Taj Mahal. When Thévenot passed through, he noted of the women “They wear a great many [rings], and as they love to see themselves, they have always one with a looking-glass set in it, instead of a stone, which is an inch in diameter.” [2]

These rings, set with a mirror, are known as “arsi” and can still be found in some areas around the country. Indeed, Sharma and Seth note in their 1997 book on contemporary regional costumes and ornaments that mirror rings were popular in the northern most reaches of India. In the western Himalayas at Chamba and as throughout India, they are still worn today. “Arsi or arsu means a mirror. An ornament with this name is a ring fitted with a round mirror or a looking-glass. It is usually worn on the thumb of the right hand. With the help of arsi, the hill woman can look at herself in the mirror and feel assured of her beauty in such places like fairs and festivals. Thus she can stealthily have a glance in the mirror whenever she desires, even in the company of males without feeling awkward.” [3]

Another reference states that in the seventeenth century arsi rings were worn by both men as well as women, but I have been unable to confirm this. In any event, they appear to have been wildly popular. On an earlier expedition through Aleppo, Syria, Thévenot observed “five or six hundred cases of [mirrored] glass” being shipped down the Euphrates River. When he expressed surprise at the rough handling, he was told “that it mattered not, though it were all broken into pieces, because the Indian men and women buy it only to have little pieces set in rings, which serve them for looking-glasses to see themselves in.” [4]

Thévenot’s first landing was in Surat on the west coast of India, about 300km north of Mumbai. Twenty years later, in 1688, Captain Alexander Hamilton landed at the same port and recorded, “The [Muslim] women wear gold rings on their fingers, and sometimes one on their thumbs, with a small looking-glass set in it.” [5] Other travelers also noticed the rings:  In the 1660’s Frenchman Souchu de Rennefort observed similarly, “They wear also many [rings] on their fingers, and among the rest, one with a small looking-glass in it, which serves them to contemplate themselves.” [6]

The earliest account I have been able to find recounts not a glass mirror but one of metal. On 25 September 1637, ambassadors from the Danish duke of Holstein were visiting the King of Persia and were entertained by six dancing women from India. The women were accompanied by their husbands who played musical instruments. “Some of them had bracelets of pearl, others of silver, but they had all rings on their fingers, and among the rest, they had upon the thumb, upon which in the place where the stone should be, there was a piece of steel, about the bigness of a crown-piece of silver, and so well polished that it served them for a looking-glass.” [7]

As these accounts suggest, vanity may well have been the motivation for the popularity of the arsi rings, but it is worth noting that mirrors did play a role in some religious practices. Wikipedia states, “The Nizhal Thangals and Pathis have, in their sanctuary, a mirror to reflect the images [of] worshippers. […] The mirror's placement symbolizes that God is inside oneself and it is of no use to seek God elsewhere.” [8] In some Muslim weddings of Southern India, a traditional ritual is called ‘Arsi-Mushaf’ or “the mirror ring and the Quran,” in which the newly betrothed observe each other through a mirror.

Thévenot stayed in India for over a year and crossed the country to its East Coast. Finally, he returned to Surat, sailed to Persia and traveled north back to Shiraz. He spent the summer of 1667 at Isfahan, after suffering an accidental gunshot wound. In the autumn, he started north for Tabriz, but died on the way at Meyaneh on 28 November 1667.


[1] Armenians in Asian Trade in the Early Modern Era, ed. Sushil; Kevonian Chaudhury (Keram). (France: Les Editions de la MSH, 2008) p. 106.
[2]Jean de Thévenot: The Travels Of Monsieur De Thévenot Into The Levant: In Three ..., Volume 3
 (London: Archibald Lovell Faithorne, 1687)v. 3,  p. 38.
[3] Kamal Prashad Sharma, Surinder Mohan Seth: Costumes and Ornaments of Chamba (New Delhi: Indus Publishing,1997), p.113
[4] Jean de Thévenot: “The Travels of Monsieur Thévenot Into The Levant” (London: H. Clark, 1687), v.2, p.40.
[5] Alexander Hamilton, A New Account of the East Indies: Giving an Exact and Copious ..., Volume 1(London: C. Hitch; and A. Millar, 1744) v. 1, p. 165
[6] Gabriel Dellon, Jodocus Crull, Souchu de Rennefort: A voyage to the East-Indies: giving an account of the isles of Madagascar (London: D. Browne, 1698) p. 25
[7] Adam Olearius, John Davies, Johann Albrecht von Mandelslo: The Voyages & Travels of the Ambassadors from the Duke of Holstein, to the ... (London: Thomas Dring, and John Starkey, 1662), p.277
[8] Wikipedia: https://en.wikipedia.org/wiki/Ayyavazhi_rituals

Monday, May 11, 2020

Thévenot Continues East

Stained glass windows of the Nasir al-Mulk 'Pink Mosque', Shiraz, Iran
Photo by Domiri Mohammad Reza Ganji.
(Click to enlarge)
Previously, we followed the progress of seventeenth century tourist Jean de Thévenot, noting his comments about glass as he traveled. He sailed from Rome to Malta to Constantinople to Egypt. He then continued overland through Syria and sailed down the Euphrates River toward the Persian Gulf.  At Basra he turned around and headed north, picking up the Tigris River to Baghdad where he continued eastward to Persia. In Isfahan he described numerous species of plants, animals and insects. Further south he took note of a city where glassmaking captured his attention:


The people of Schiras [Shiraz, Iran] are very witty and the city hath given birth to most of the best poets of Persia. There is much glass made there, and several glass-shops are in town, though they work not constantly in their glass-houses, but let the fire go out after they have employed a certain quantity of materials. They make their glass of a white stone, almost as hard as marble, which they get in a hill four days journey from Schiraz and it is very clear: especially they make great bottles as clear and delicate as in any other place in the world; but it is wonderfully strange how they can blow the great bottles they call ‘Caraba,’ which are as thick as one finger and hold nearly thirty quarts of wine; these bottles are covered with the straw of canes. [1]

Preceding Thévenot in Shiraz by a number of years (1627) was the British traveler, Sir Thomas Herbert, who stated that there was “…no part of the Orient showing better or richer wine.” [2] The mutually beneficial association between the production of wine and glass is one that appears in numerous locations throughout history. That both crafts should occur here, at the center of activity for this region’s premier vineyards should be no surprise. 

The region’s ‘Shirazi’ wines have been connected by various legends to the French Rhone variety now known as ‘Shiraz,’ but the vineyards in Iran are now defunct, and no definite conclusions have been reached, except that if a kinship exists, it is a very ancient one. In other quarters, Marco Polo mentioned Persian wines [3] and Omar Khayyam praised them throughout his Rubaiyat. [4]

At the same time that Thévenot passed through the region, so did fellow Parisian Jean Chardin (Sir John Chardin) who spent about eighteen months visiting (1666-7). It is unknown if the two travelers met. In his own published diary Chardin stated  “The art of glass-making; there are glass houses all over Persia, but most of the glass is full of flaws […] The glass of Chiras [Shiraz] is the finest in the country” and he went on to say that “Moreover, the art of glass-making was brought into Persia within these four score [80] years. A beggarly and covetous Italian taught it at Chiras for the sum of fifty crowns.” [5]

This last passage is often quoted in reference books without comment, to the point that it has become quite famous. At the risk of stating the obvious, the notion that one man, a foreigner, down on his luck, could single handedly bootstrap an entire industry that would fully mature throughout Persia in eighty years is absurd on its face. Beyond that, it is something of an insult to a culture that current scholarship credits with key developments in the invention of glass more than five thousand years ago. [6] Chardin’s condescendence toward Persian artisans and craft in general is well demonstrated throughout his book. His claim is plain enough, however if we want to be charitable, we could speculate that he misunderstood his source, who actually told him that the Italian was responsible for showing European style glassmaking to a well established technical community in Shiraz. Historian Stefano Carboni identifies a fifteenth century downturn and says “in Iran the industry was revived with the help of European, mostly Venetian, craftsmen in Isfahan and Shiraz from the seventeenth century.” [7]

[1] Thévenot v.2, p. 125, 126
[2] Thomas Herbert  “A Relation of Some Yeares Travaile, Begunne Anno 1626.” (London: Stansby and Bloome, 1634), p. 133.
 By Thomas Herbert   also see http://www.saddleflasks.com  “An extensive reference site devoted to Late Persian glass.”
[3] By Marco Polo, “The travels of Marco Polo, the Venetian,” trans. by William Marsden (London: J.M. Dent, 1926), p. 41 (bk.1 ch. 15).
[4] Omar Khayyam, “Rubaiyat of Omar Khayyam” trans. by Edward Fitzgerald (Boston: Branden Books, 1989), for example, stanzas VI, XI, XII, XLI, LVI.
[5] John Chardin “Sir John Chardin's Travels in Persia” (New York: Cosimo, 2010) p.275  (abridged English translation of 1724 original).
[6] For instance, see  https://en.wikipedia.org/wiki/History_of_glass http://www.iranicaonline.org/articles/glass ,  https://en.wikipedia.org/wiki/Sasanian_glass .
[7]  Stefano Carboni, “Glassware” in Medieval Islamic Civilization: An Encyclopedia edited by Josef W. Meri (New York, Routledge, 2005) v. 1, p. 298.

Friday, May 8, 2020

Travels to the East


Jean de Thévenot, from
"Relation d'un voyage fait au Levant" (1664)
In 1652, at the age of eighteen, a wealthy Frenchman named Jean de Thévenot finished his studies at the University of Paris. He celebrated his achievement with a grand tour that would take him, not just through Europe, but unexpectedly half-way around the world, where among other things he would find glass being made. 

In Rome, he befriended fellow Parisian, Barthélemy d'Herbelot, where they conspired to travel together to the Levant. 

Circumstances detained d'Herbelot and after waiting five months in Malta, Thévenot gave-up on his companion and set out on his own to Constantinople. Four years later, in 1659. He returned home only to prepare for an even more epic adventure, one that would last until his 1667 death in Azerbaijan from an accidental pistol shot. 

Thévenot kept a travel diary, he picked up languages easily and endeavored to blend-in to local culture as much as possible. Throughout his travels he made keen observations of people, customs and of the natural world around him. He published a volume of his adventures to great acclaim, two more would follow after his death. In 1687 his work was translated into English, when it found a whole new audience. 

Of special interest to us are his numerous observations about the glass trade. This was a subject to which he had no special interest or connection, but his natural curiosity and communication skills open a window into an otherwise poorly documented piece of the glass history puzzle.

On Malta, even before embarking for the Far East, he notes that “sore eyes” are a problem because of the bright sun on the white (limestone) earth of the island “which makes many commanders and knights wear green spectacles”; certainly an early incarnation of sunglasses. [1] In Constantinople (today Istanbul) he visited the great mosque Hagia Sophia and remarked “it is full of lamps and curiosities in glass balls, of which one for instance, contains  a little galley, well rigged, another a model of the mosque in wood and the rest a great many pretty knacks of that nature.” [2] Having booked passage out of Alexandria, Egypt on an English gun boat, he explains that the sailors kept track of their speed with a “little slat and very thin piece of wood tied to a line and when they throw it into the sea, they turn a half-minute sand glass […] every seven fathoms of the line making a mile in an hour.” [3] This is the origin of the nautical unit of speed known as the 'knot', the method of paying out line spaced with knots tied in the line at intervals of  8 fathoms - 47 feet 3 inches (14.4 m). This method of reckoning progress with a line was used well into the nineteenth century, the units are still used today, both for boats and aircraft.  A vessel travelling at 1 knot along a meridian travels approximately one minute of geographic latitude in one hour. [4]

In Damascus, Syria, he visited the great mosque there (Umayyda). Some natives kindly offered to take him in, disguised with a turban on his head, but he declines, fearing that if discovered, he will be forced to choose between his life and his Christian faith. Nevertheless he walks around the tremendous structure and observes that “The pavement is all of lovely stones that shine like lookinglass” and he continues “I went up to the terrace-walks, to the windows of that mosque, which are made like the windows of our churches and have panes of glass set in plaster, which are wrought into figures.” [5]

West of Aleppo, Syria, on the banks of the Euphrates River, Thévenot explains that, “barks loaded with glass (of which I will presently speak,) go to Bassora [Basra].” A ‘bark’ or ‘barque’ was a small three masted sailing ship. “While I was at Aleppo, the Sheik Bandar hired a bark to carry five or six hundred cases of glass, which he sent to the Indies.” And “I wondered to see that they who baled up these chests for the Sheik Bandar, tumbled them so rudely that they broke all the glass; but they told me, that it mattered not, though it were all broken into pieces, because the Indian men and women buy it only to have little pieces set in rings, which serve them for lookinglasses to see themselves in. That glass is all over laid with quicksilver on one side and is a very salable commodity in the Indies and profitable to the merchants.” [6]

One implication from this passage is that the named Sheik Bandar ran a glassmaking operation in Aleppo. It is interesting to note that Florentine glassmaker Antonio Neri had an uncle, his father’s brother Francesco, who was a merchant living in the Tuscan enclave inside Aleppo about sixty years earlier.

In the next installment we will continue to follow the thread of glassmaking references in the chronicles of Thévenot’s travels which take him to Persia, where he finds a glassmaking center.

[1] Jean de Thévenot, “The Travels of Monsieur Thevenot Into The Levant” (London: H. Clark, 1687) v.1, p. 6.
[2] Ibid, p. 22.
[3] Ibid, p. 268.
[4] See Wikipedia http://en.wikipedia.org/wiki/Knot_(unit).
[5] Ibid, v.2, p 17.
[6] Ibid, p.40.

Wednesday, May 6, 2020

Early Modern Aleppo

Aleppo, 1764
Antonio Neri is famous for  his 1612 book on making glass, [1] but in the late sixteenth century his father was also famous; Neri Neri, as he was called, was a graduate of  the esteemed 'Studio Fiorentino', head of the Florentine physicians and apothecaries guild, and royal physician to the grand duke of Tuscany, Ferdinando I de’ Medici.  

In those days, one of the best connections a physician could have was a reliable associate who could procure the exotic herbs and remedies prepared in the Orient. To have such a contact in one's family was even better, but perhaps best of all was an older brother who was a merchant living in the fabled city of Aleppo, located in Syria at the very end of the Silk Road. The brother of Neri Neri was named Francesco or "Franco" [2] for short and Aleppo was no ordinary city; it was a sort of international crossroads for traders connecting north and south, east and west. It was where silk and cotton were traded for wool and metals, where gold and silver changed hands for rubies and lapis, and where exotic spices and medicinal preparations could be found and exported to places like Venice and  Florence. [3] In 1583, Englishman John Eldred passed through Aleppo and recorded this:
[W]e passed forward with camels three dayes more untill we came to Aleppo, where we arrived the 21 of May. This is the greatest place of traffique for a dry towne that is in all those parts: for hither resort Jews, Tartarians, Persians, Armenians, Egyptians, Indians, and many sorts of Christians, and enjoy freedome of their  consciences, and bring thither many kinds of rich merchandises. In the middest of this towne also standeth a goodly castle raised on high, with a garrison of foure or five hundred Janisaries [Sultan’s guard]. Within foure miles round about are goodly gardens and vineyards and trees, which beare goodly fruit neere unto the river side, which is but small; the walls are about three English miles in compasse, but the suburbs are almost as much more. The towne is greatly peopled. [4]
Aleppo has been in continuous occupation since prehistoric times; at least as far back as 5000 BCE, according to archaeologists. Stones were laid there before there was paper or written language or glass for that matter. There is a legend that the Arabic name for Aleppo, 'Halab' once meant "gave out milk" and was a reference to when Abraham gave milk from his white cows to travelers as they passed through the area. 

1563, when Franco Neri was still a young man of twenty-six, living in Aleppo, both he and his father were referenced in a couple of documents.  They are still held in the grand ducal archives in Florence, written in the reign of Cosimo I de' Medici. [5] This indicates, at the very least that the Neri family was in service to the leaders of Florence three full decades before Antonio Neri would make glass for Prince Don Antonio de' Medici.

In the sixteenth century the Christians in Aleppo lived in a tightly knit neighborhood that developed as a result of an Ottoman invasion around 1400. There were four churches standing side by side in the Jdeydeh quarter, only the old Maronite Church of Saint Elias was associated with the  Roman Catholic Church. If Franco Neri was in town when the above John Eldred passed through with his two companions, it is not impossible that they could have attended mass in the same church one Sunday in late May of 1583. 

Two decades later, the Emir (prince) of Aleppo, Fakhr-al-Din II forged an alliance with Tuscany, which apparently involved both economic and military provisions. He was attempting to break free of the Ottoman Empire and is considered by some to be the father of the Lebanese independence movement. He would go on to spend a number of years visiting Italy and Florence in particular, where he formed a friendship with then Grand Duke Cosimo II. 

Today, the beautiful, ancient city of Aleppo stands mostly deserted and partly demolished by war. Some news stories sight the determination and character of the current independence movement by quoting a poet, al-Mutanabbi, who lived in the mid tenth century. He spent the better part of a decade at the royal court of Aleppo, where it is said he did his best work. His most quoted lines are from a piece sometimes called "the poem that killed the poet." A legend tells that one night he was cornered by his enemies. Ready to flee, he was reminded of his own words by a servant, which caused him to stay and fight. The poem closes this way:


The desert knows me well, the night and the mounted men. 
The battle and the sword, the paper and the pen. [6]


[1] Neri, L’Arte Vetraria. (Firenze: Giunti, 1614).

[2] Registri Battesimali Firenze, reg. 10, f. 71v.  3 Feb., 1537, born to Jacopo Neri, barber [and surgeon] from dicomano, in the parish of San Ambrogio, Florence. (A couple of blocks from the Borgo Pinti childhood home of Antonio Neri.)

[3] Gian Pietro Vieusseux, Archivio storico italiano,  vol. 141, Issues 517-518 (Firenze, Leo S. Olschki, 1983), p. 370. “His correspondence also makes several references to the activity carried out by the Venetian court who had often had occasion to attend to solicit the interests of friends or acquaintances as Francesco Neri of Aleppo, the Capponi and Rinuccini [families].” 

[4] Richard Hakluyt, A selection of curious, rare and early voyages ..., (London: R. H. Evans, 1810)v. 2,  p. 403. “The voyage of M. John Eldred to Tripolis in Syria by sea, and from thence by land and river to Babylon and Balsara. 1583”

[5] Carteggio universale di Cosimo I de Medici /XI Archivio di Stato di Firenze Inventario XI (1560 – 1564) Mediceo del Principato Filze 489-499°, pp. 162, 206; /XII (1562-1565) Filze 500-514 p. 60.

[6] al-Mutanabbi (915-965 AD). He is thought to have spent nine years in Aleppo where he composed some of his best work, http://en.wikipedia.org/wiki/Al-Mutanabbi  See also http://aminotes.tumblr.com/post/33116016101/aleppo-a-city-in-flames 

Translated into German by Friedrich Dieterici, ed, tr. Mutanabbii carmina cum Commentario Wfthidii, (Berlin, 1858-1861), pp. 481-4. vv. 1-22, then into English by Nicholson, who wrote of Mutanabbi, “Although the verbal legerdemain which is so conspicuous in his poetry cannot be reproduced in another language, the lines translated below may be taken as a favorable and sufficiently characteristic specimen of his style.” Reynold A. Nicholson, A Literary History of the Arabs (Unwin, 1907).p. 307. Subsequently Nicholson published the present version in Reynold A. Nicholson, Translations of Eastern Poetry and Prose (Cambridge: Cambridge U. Press, 1922), p. 80. 

Monday, May 4, 2020

Glass Discovery Legend

Giovan Maria Butteri,
"The Discovery of Glass"
Studiolo of Francesco I de' Medici
Any self-respecting Roman historian living in the first century could tell you the story that glass was first discovered by Phoenician sailors. They were temporarily grounded at the bay of Haifa, near the Belus River, in the shadow of Mount Carmel, forced ashore by a storm. Needing to eat, they improvised a fire on the beach in order to cook their food. Using natron, a mineral they were carrying as cargo on the ship, they built up a stove. To their amazement, in the heat of the fire, the natron mixed with the beach sand started to melt and liquid glass trickled out.

Actually, starting with Pliny the Elder, the author of the most famous version of this story, skepticism abounds about how much of it was true. Nevertheless, if we gently tease apart the loose threads of this yarn we find that it is not without substance. First, there is the location; not just any port in a storm, this region was the site of a thriving glass industry as early as the sixth century BCE, due to the exceptional, pure white sand at the outlet of the Belus river. Archaeologists have excavated ancient glass furnaces at the nearby cities of Tyre and Sidon.

Next, the sodium carbonates in natron do indeed form glass when mixed with fine sand and brought to a high temperature, but this takes strong, concentrated heat, likely more than could be provided by a cook's beach fire. However, there is another possible explanation; natron is a hydroscopic mineral – this means it pulls moisture out of the surrounding environment. The water is locked into its solid crystal structure, where it remains until it is released either chemically or through heat. Natron can hold a remarkable amount of water, up to two-thirds of its weight. This is why it was used extensively to preserve mummies in Egypt; it dried out the bodies, soaking up moisture, quickly preserving them. While the story of the Phoenician sailors deserves a healthy dose of skepticism, it is also easy to see how the decomposition of the natron in the fire, resulting in the release of briny liquor, might be misinterpreted as glass, which then disappeared into the sandy beach.

In the early 1600s glassmaker and alchemist Antonio Neri published the very first printed book of glass recipes, and in his introduction he too recounts the tale. However, in Neri's telling, natron does not make an appearance. Instead, the sailors use 'kali,' a coastal plant that is rich in alkali salts, to fuel their fire. The salts in kali are substantially similar to natron and, according to the story, triggered a similar result. In this period, Kali ash was a well-known ingredient in glass making. Neri used it in his own recipes, so the substitution is not surprising, but in this respect, Neri's version of the story with kali does appear to be unique in the literature. It is interesting to note that Lodovico Domenichi, who was good friends with Neri's grandfather, tells a version of this story in his Italian translation of Pliny's Natural History. Here the sailors use natron, but in the next paragraph, Domenichi describes how local natives later used kali plants to make their own glass.

The above depiction of the discovery of glass was painted by Butteri, one of a select group of painters for the Medici court in Florence. The work was commissioned to hang in the secret "studiolo" laboratory of Francesco de' Medici, a concealed barrel vaulted room tucked under a staircase in the Palazzo Vecchio in the early 1570's. It was only accessible through secret passages, one leading from Francesco's bed chamber. Another led from the chamber to an unmarked door on the street and a third passage led from the chamber to the secret treasury room once used by his father, Grand Duke Cosimo I. The walls and ceiling were entirely filled with paintings, the lower ones concealing cabinets full of oddities of nature, precious gems, coins, alchemical concoctions, and other treasures. Presumably, the cabinet behind Butteri's "Discovery of glass" would house some of the intricate Venetian glass vessels for which the craftsmen of Murano had become world famous. Shortly before the room was completed, a small number of these glass masters were allowed to teach their secrets in Florence by special arrangement with the Venetian government.

This post first appeared in a shorter form here on 9 October 2013.

Friday, May 1, 2020

Laughing in the Fern

Alain Manesson Mallet  1719,
"Der Mont. – Lune"
In Chapter 5 of L'Arte Vetraria, Antonio Neri shows how to extract salt for glass from fern plants in an evocative recipe. Fern was and still is widely abundant in Tuscany. It presented a ready source material for glassmakers of the region. Neri directs that harvesting of the plants be done in the spring:
Cut this herb from the ground when it is green, between the end of the month of May and mid June. The moon should be waxing and close to its opposition with the sun, because at this point the plant is in its perfection and gives a lot of salt, more than it would at other times and of better nature, strength and whiteness.
At first, it is tempting to dismiss this lunar influence as the product of a fertile imagination, but let us take a closer look. Even today, grandmothers throughout Italy remember the advice to pick vegetables from the garden and bring them into the kitchen at a half-moon. Can nona be completely off-track? The fact is that tidal forces of the moon do subtly affect plants, fish and animals in ways that can be measured. A closer look at Neri’s advice reveals reasoning that is hard to dismiss as mere astrological superstition. When the moon is waxing, tides rise and so do water tables. According to folklore, this is when sap rises from the roots of plants into stems and leaves. Sap carries the dissolved mineral salts required for glass. Neri also stipulates that harvesting should take place during lunar opposition. When the moon is 'opposed' to the sun, it is on the opposite side of the earth from the sun. In opposition, the moon is near full and rises as the sun sets. Plants see more light at night, leading to increased photosynthesis and growth.

In contrast, violin makers from Cremona valued high alpine spruce called moon wood which contain a minimum of sap. Trees were felled in the wintertime, when lunar tides were low. This minimized the amount of vibration deadening sap in the wood. In his Natural History, Pliny relates Cato’s advice on felling trees in accordance with the lunar cycle. In fact, centuries-old tradition specified lunar conditions for a host of needs from construction timbers to cheese boxes. In this case the advice relates to picking ferns for use in glass.

Fern ash is high in potassium carbonates. If carefully purified it can make an exceedingly clear glass, rivaling or even surpassing Venetian cristallo. It has the additional advantage of being physically tough, making it ideal for engraving or diamond-point work. On the other hand, once out of the furnace it stiffens quickly, giving it a short 'working life' for the hot glass artisan. This limits designs to simple basic forms. While soda-based glass was the norm for the Mediterranean region, throughout the Middle Ages and into the Renaissance, northern Europeans were more likely to be making potash-based glass. They utilized the potassium rich local trees and plants of the northern forests. In France, fern glass is called verre de fougère. In the considered opinion of some connoisseurs, wine tasted better when sipped from verre de fougère cups, hence the delightful expression 'le vin rit dans la fougère' [wine laughs (sparkles) in the fern].

Since the middle ages, fern glass became part of everyday life in northern Europe. It was familiar enough to find its way into literary verse on matters of the heart. There is a nice reference to fern glass by Geoffrey Chaucer, in The Squires Tale:
But notwithstanding, some said that it was
Wondrous to make fern-ashes into glass,
Since glass is nothing like the ash of fern;
But since long since of this thing men did learn,
Chaucer, in turn, borrowed this reference from an epic twenty-two thousand line French poem from the late thirteenth century, when the technique of making glass from ferns was already ancient.

* This post is a mashup of material that first appeared here on 5-7 August 2013.