Friday, January 31, 2014

Turning Iron into Copper

The recovery of copper from vitriolated waters,
from De Re Metallica, 1556, by Agricola (Georg Bauer).
In Discorso, one of the last manuscripts written by Antonio Neri before his death, he reveals several transmutation recipes. One describes turning iron into copper; it is instructive because it uses common materials that we can identify and because the chemistry is now well understood.

Take some iron sheets and lay them in vitriol water, being immersed in that, they will rust. Scrape off this rust, which will be a red powder, melt it in a crucible, and you will have perfect copper. The same effect can be had from various waters that are naturally vitriolated, because they flow through mines of vitriol, such as those of a source some distance from Leiden, and another below the fortress of Smolnik, [now in Slovakia].

Vitriol is an acidic sulfate dissolved in water, it could be made in the laboratory, but it also occurred naturally around mining operations where sulfurous minerals were present. Alchemists knew this solution as "oil of vitriol" and "spirit of vitriol." The mine that Neri references in Smolnik became famous for transmutation. As late as the eighteenth century, scientists and experimenters from around Europe made the pilgrimage to see the effect for themselves and tried to figure out what was happening. It may be a surprise to some readers, but following the above instructions will, in fact, produce copper just as Neri claimed. There is no deception or sleight of hand involved; the explanation is straightforward, but first, Neri treats us to a rare glimpse of his own reasoning on the subject:

Some estimate and not without reason, that this experiment, being used to prove the transmutation of metals, is not suitable for this purpose. They say that the vitriolated waters become such because they are already heavy with the corrosive spirits of sulfur, having passed through the copper or iron mine, these waters corrode copper in the same way aqua fortis corrodes silver. So that really the substance of the copper remains in the water, which attacks the surface of the iron, which always remains iron. However, if that were true then the iron would not get consumed, or if it were consumed it would mix with the substance of the corroded copper in the water, and if it were fused, it would remain a mixture of iron and copper. And yet in this experiment, all the iron is consumed; it is reduced by the vitriolated water into powder, […] which in the fusion is still pure copper, so there should remain no doubt that this is a true transmutation.

Given the state of chemistry at the time, Neri's reasoning is clear and rational. The iron disappears and a copper coating materializes in its place. What better evidence of transmutation could one ask for?

The key to what was actually happening is in the criticism leveled by skeptics. It turns out that they were on the right track, but neither they nor Neri had the full picture. Today, we understand it as a simple ion exchange reaction; blue vitriol water is a transparent saturated solution of copper sulfate (CuSO4), in the presence of solid iron, the liquid dissolves the iron; copper from the vitriol is deposited in its place. The two metals, copper and iron, change places: the iron dissolves, forming green vitriol (FeSO4) and copper is expelled from the solution. The result is a reduction in the amount of the iron, which is replaced by a proportional deposit of pure copper.

On a physical level, this chemical reaction is no different today than it was in the seventeenth century. What has changed is our interpretation of the experiment. What Neri viewed as a transformation of iron into copper, we now see as an exchange. There is, however, a deeper lesson in all this. As an alchemist, Antonio Neri was not being delusional or dishonest; he was careful, observant and applied his knowledge as best he could. This is no different from the way science works today. Both then and now, to be successful in unraveling nature’s secrets, one must become accustomed to a very uncomfortable situation: In the past, careful reasoning by brilliant thinkers has led to utterly wrong conclusions. The fact that much of our world is a mystery is unsettling; that the very process we use to understand it can be so flawed is harder to accept. Even more difficult is that the faculty we all rely on for survival—our own wits—can lead us so far astray.

For more, see Discorso sopra la Chimica: The Paracelsian Philosophy of Antonio Neri”, M.G. Grazzini / Nuncius 27 (2012)

Wednesday, January 29, 2014

Antonio Altoviti

Tomb of Antonio Altoviti
Dei Santi Apostoli Church, Florence
Of all the godparents to Antonio Neri's siblings, young Jacopo Neri's godfather was perhaps the most notable. Antonio Altoviti, the Archbishop of Florence, was a very controversial archbishop. It is an understatement to say that the relationship was tense between him and the first Grand Duke, Cosimo I de' Medici. The root source of the animosity, however, was not with Antonio Altoviti but with his father, Bindo. Bindo was a banker to four popes beginning with Paul III. He was heir to one of the largest fortunes in Italy, and an avowed enemy of the Medici. His friends included artists Raphael, Michelangelo, Cellini and Vasari. As an administrator at the Vatican, he managed the project to rebuild St. Peter's Basilica. While his wife and family continued to live in Florence, Bindo and his son spent most of their time in Rome, out of reach of the Medici. In 1555, Cosimo confiscated Bindo's Palazzo in Florence; he then made a gift of it to his youngest son, Don Giovanni Medici, who would add a laboratory and there conduct alchemy experiments. Although later reconfigured into a much larger palace, The Casino del Parione, now called the Palazzo Corsini al Parione still stands on the banks of the Arno River.

Bindo spent a fortune raising an army to oppose Cosimo in the war over Siena. Earlier, he was accused of complicity in the successful assassination plot against Cosimo's predecessor, Duke Alessandro de' Medici. He was an outspoken critic who wanted the Medici out of power permanently and he backed up his words with considerable resources. In 1548, as a poke in the eye to Cosimo, Pope Paul III appointed Bindo's son, Antonio Altoviti, as Archbishop of Florence. Cosimo retaliated by banning the new Archbishop from setting foot in the city, a prohibition that lasted for twenty years. Cosimo finally relented as part of papal negotiations that secured his new title of "Grand Duke." Antonio Altoviti was a devotee of the late great revolutionary cleric Girolamo Savonarola, decidedly not a Medici favorite. By some accounts, the high regard with which the people of Florence held the Archbishop only intensified Cosimo’s dislike. 

Nevertheless, he did ultimately gain the trust of Cosimo's inner circle; in 1567 Altoviti was involved in negotiations to bring Venetian glass workers to Tuscany. This effort would bear fruit within a couple of years. It is perhaps impossible to gain full appreciation of a man through a single anecdote, but we can get a flavor. In 1569, shortly after occupying his post for the first time, Altoviti introduced a new ritual to the Florentine Church. On Holy Thursday, the Bishop would wash the feet of twelve of the city's poor residents rather than of twelve canons (as done previously) and he would give them generous alms.  

What makes Archbishop Altoviti so interesting to Neri's story is that he had a close association with the Neri family. In fact, so close that on 13 December 1573, Altoviti became godparent to Jacopo, the first born son of Neri Neri and Dianora. It is an interesting choice for a man who would later become personal physician to Cosimo de' Medici's son, Grand Duke Ferdinando. However, Jacopo would never learn what it was like to have the Archbishop as his spiritual guide. Two weeks after his birth, on the 28th of that month, Altoviti convened a special post-Christmas meeting of regional bishops. It was during this synod that he suddenly and unexpectedly died at the age of fifty-two. Within a few years, young Jacopo would join him.

Monday, January 27, 2014

Caterina Sforza

Caterina Sforza, by Lorenzo di Credi
(now in the Museum of Forlì.)
Antonio Neri is remembered mostly for his book on glassmaking, L'Arte Vetraria. However, he considered himself first and foremost an alchemist. This interest can be traced to at least two generations before him; his father, Neri Neri, was an acclaimed physician – in fact, the personal physician to Grand Duke of Tuscany, Ferdinando I de’ Medici. Antonio's grandfather, Jacopo Neri, was a barber-surgeon. Both of these professions required an extensive knowledge of herbal distillation and other techniques which are shared by alchemists.

Antonio's benefactor, Don Antonio de' Medici, also followed a family passion for the chemical arts, in his case, traceable through an unbroken chain, to a female alchemist, his great-great-grandmother, Caterina Sforza, (c.1463–1509). After her death, over four hundred of her formulas were passed down to her son, Giovanni dalle Bande Nere, then to his son Grand Duke Cosimo I de' Medici, Grand Duke Francesco I, and finally to Don Antonio. 

She was the illegitimate daughter of the Duke of Milan, Galeazzo Maria Sforza, but was still educated at court. At age fifteen, she was married to a nephew of Pope Sixtus. The pope granted her title of Countess of Forlì and Imola. After her territory was later taken and her husband murdered (by a faction of their own people), she escaped prison and retook the two cities. In 1495, when her second husband was assassinated, she launched a campaign which gutted the families of the murderers. Her third husband was Giovanni de' Medici, and their son, named after his father would become a brilliant military strategist, like his mother. His own son, Cosimo, would later become the first "Grand Duke" of Tuscany. 

Her chemical recipes were transcribed in 1525 by a captain in her son's army, Count Lucantonio Cuppano da Montefalco, and ultimately published as a book in 1893 (Passolini). Included are an assortment of formulas which range from cosmetics, to medical remedies, poisons and alchemical concoctions.
Researcher Jacqueline Spicer writes:
Lost among the romanticized military conquests is a thorough account [of] the project that occupied several years of her life—the manuscript of her alchemical and medical experiments and recipes titled Gli Experimenti de la S.r Caterina da Furlj Matre de lo S.r Giouanni de Medici, or Gli Experimenti. The text is an early example of what would later become the popular medical genre of "Books of Secrets", but is so early that it does not appear in most modern writing on such books. Furthermore, Gli Experimenti is unusual because it was written by a woman in an otherwise male dominated genre, and unique in that we know a great deal about the life of its author.

Among the alchemical entries are "to convert pewter into silver of the finest quality and of standard alloy," a method "for giving to bars of brass a fine golden color" and another for "for multiplying silver." Also, there are ways described  to "make iron hard," "to dissolve pearls" and "to dissolve all metals." In the medicinal category, we find "for infirm lungs, an ointment is to be made of the blood of a hen, a duck, a pig, a goose, mixed with fresh butter and white wax." This was to be applied to the chest on a fox's skin.
Sandro Botticelli, Primavera (1498)
(detail - rightmost of the three graces)

Caterina Sforza was painted many times and often depicted as the Virgin Mary, a typical trope for the nobility at the time. She may have been immortalized  by Sandro Botticelli as the rightmost of the three graces in his Primavera and as the main subject in The Birth of Venus.* Reportedly, she was the subject of ballads and sonnets, although most have been lost. She is a topic of discussion in Niccolò Machiavelli's famous treatise The Prince

In the end she was captured, raped and imprisoned on the orders of Pope Alexander VI, who justified her incarceration, in the Vatican's  Sant'Angelo Castle, by claiming she tried to poison him. She survived the ordeal, but after release entered the convent of the Murate nuns in Florence, and died, in 1509, at the age of forty-seven. She was buried at the convent, in the same city where her future great-great-grandson, Don Antonio, along with Antonio Neri, would perform their own alchemical experiments and help usher in the age of  modern science.

Another possibility was Simonetta Vespucci for the model of Venus.

Friday, January 24, 2014

The Glass Furnace

From "De re metallica"
Agricola (Georg Bauer) 1556.
In the seventeenth century, glass furnaces represented a pinnacle of technology. True, the ability to achieve the high temperatures required to melt glass had been around for centuries – high enough to melt gold, silver and copper as well. What made the glass furnace remarkable was its refinement. It made efficient use of its hardwood fuel and was able to maintain a controlled, even temperature long before any thermometer could measure it. In fact, Galileo was only just beginning to use glass bulbs and tubes to measure differences in ambient room temperatures.

In Florence, the construction used was typical of the time throughout Europe, called a "beehive" furnace because its shape resembled the elongated dome of a beehive. A double wall, built of fire resistant bricks, provided further insulation, trapping heat inside. Vertically, the furnace was divided into three levels, each forming a wide open chamber. The bottom space was used to build the fire, and had one or two openings to the outside, used to add wood fuel, rake the coals, or shovel out ash. The second, central level was where the pots of glass resided. A central hole or "eye" on the floor directly exposed the fire pit below. The space directly next to the eye was the hottest, and temperature could be further controlled by moving the crucibles farther away or closer to the eye. A number of openings in the wall allowed gaffers access to the glass pots, and at least one larger opening was used to place new crucibles, or rearrange the existing ones. The upper chamber was used to control the draft, and sometimes for annealing. Again, a central hole in the floor of this (top) level allowed exhaust gasses to leave the glass chamber and an opening to one side vented the exhaust.

In his book, L’Arte Vetraria, Neri is careful to stress that only dry oak or other hardwood should be used because it burns cleanly, and will not deposit ash or creosote in the glass.
The furnace should have dry wood, hard wood of oak because soft wood tinges the furnace and does no good. Stoke it steadily and continuously so that the flame is always clear, and there is never any smoke, which is very important in order to make a beautiful cristallo.
Once a finished piece of glassware is made, it must be allowed to cool slowly, over a period of many hours. This was often accomplished by building a long enclosed horizontal trough that connected to the furnace. A draft opening at the far end allowed heat from the furnace to be drawn in, and finished pieces were placed in a pan at the furnace end and then slowly pulled by a chain further and further down the trough toward the cooler end. This "annealing" process ensured the glass would not develop stresses and crack as it cooled.

Although Neri does not concern himself with the vagaries of furnace construction in the book, it is clear that he did possess considerable knowledge on the subject. Several of his unconventional methods for making pigments for glass involve taking bricks out of the furnace wall to stash chemicals for long term exposure to the heat.
Take small pieces of copper and put them inside the arches of the furnace. In that place, they will be within the walls. Leave them that way until each piece of copper is well calcined, using a simple fire.
While it is true that artisans of the early seventeenth century did not possess the same understanding of nature that we now enjoy, they did have a working knowledge that served them very well. It was backed by a theoretical framework that was quite sophisticated and was consistent with what could be observed and measured at the time. This is no different from our own modern understanding of nature: sophisticated and consistent with what we can observe and measure.

Wednesday, January 22, 2014

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 Frankfort 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?

Monday, January 20, 2014


Fleur-de-lis, symbol of Florence, Italy.
In early 1611, Antonio Neri returned to Florence after visiting a good friend in Antwerp; a visit that had lasted seven years. It is not known if such a long sojourn was planned from the start, but it seems unlikely judging from correspondence leading up to the event. Neri only first met Emmanuel Ximenes (pronounced "Si-men-ez") a couple of years earlier, in 1601. The two men were introduced at the house in Florence, where Neri was living at the time, by his landlord Alamanno Bartolini and his wife Beatrice. Emmanuel was Beatrice's brother; he and Antonio quickly realized they shared a strong interest in alchemy, medicine and also glassmaking. Ximenes was a wealthy banker, probably in Florence on business, and soon he returned to Flanders, but started a correspondence with Priest Neri that would culminate in the priest's visit.

A clue to the unusual length of the stay may be found in stories that were printed long after both men were dead. In the 1840s, the distinguished historian and archaeologist Francesco Inghirami published his encyclopedic History of Tuscany, saying about Neri:
He was poor and the House Master for the Bartolini [family] of Santa Trinita. He 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. After the death of the two attackers, he returned to Florence.

The political situation in Flanders was tense, and had been for Neri's entire time there. The Protestant Dutch to the north were in a bloody war for independence from Spain and the Habsburg Empire. All around Antwerp cities and towns were being sacked and destroyed as troops vied for control of the territory. Catholic Antwerp became an island of calm in a sea of trouble. Battles raged around it, but the city itself was considered too valuable an asset for either side to pillage.

By the time Neri set off for home, a truce had been signed between the Dutch and Spain over the Low Countries, but it was an uneasy truce at best. Soldiers and cavaliers who had not been paid in months clogged the roadsides around Antwerp and Liege. There was unrest deep within Dutch held territory as well. In Utrecht, a popular uprising in January of 1610 threw out much of the local government over religious, social and political issues. Then in May, a Catholic fanatic assassinated King Henry IV of France. His widow, Florence's own Marie de' Medici, had been crowned in a ceremony the previous day. At Cologne, frantic negotiations were underway over the religious destiny of all Germany. By September, boatloads of English Catholic refugees were streaming into Leghorn on the Italian coast just west of Pisa. They had been expelled from Britain over the Gunpowder Plot.

What Antonio found upon his return to Florence, was a city very much familiar in outward appearance, but perhaps a bit less so on the inside. Grand Duke Ferdinando "of blessed memory" – as Neri eulogized in his glass book – had died in 1609. As a result, Prince Don Antonio de' Medici, Neri's sponsor, found himself even more marginalized from the royal family. Former landlord Alamanno Bartolini was dead, as was Giambologna, the famous sculptor. He was Neri's neighbor whose workshop and residence was directly across the narrow street from Antonio's childhood home. Neri's own family matriarch, his grandmother Maddalena, had also died within days of the grand duke, making Antonio and his siblings the elders of the Neri family.

This was the Florence to which Antonio returned, and in which he settled down to collect his notes and within a few months write the book, L'Arte Vetraria, for which he will forever be remembered: the first book ever printed that is entirely devoted to making glass.

Friday, January 17, 2014

Mirror, Mirror On the Wall

Jan van Eyck
The Arnolfini Portrait (1434)
L’Arte Vetraria, Antonio Neri's 1612 book, would eventually become the glassmakers' bible throughout Europe. By 1900 it had been translated into six different languages; Italian, English, Latin, German, French, and Spanish (and in this century Japanese). Because of its seminal importance in the spread of glass technology, often overlooked are a few recipes at the back of the book, which have only a tenuous connection to the main subject.

Among these is a metallurgical formula for making convex mirrors. Neri gives instructions for producing what we would now call a "white bronze" that may be cast into a rounded form and polished to take on a highly reflective surface finish. This "spherical" form of mirror was popular throughout the Renaissance. It reflected a wide-angle view of the space in which it was hung, but at the cost of distorting the image. Nevertheless, upon looking into such a mirror, objects are still quite recognizable. 

Here is Neri's prescription:
A Mixture to Make [Mirror] Spheres:
Have 3 lbs of well-purified tin, and 1 lb of copper also purified. Melt these two metals, first the copper, then the tin. When they fuse thoroughly, throw onto them 6 oz of just singed red wine tartar, and 1½ oz of saltpeter, then ¼ oz of alum, and 2 oz of arsenic. Leave these all to vaporize, and then cast [the metal] into the form of a sphere. You will have good material, which when you burnish and polish, will look most fine. This mixture is called acciaio and is used to make spherical mirrors.
Of note is the fact that the word Neri uses for this alloy, acciaio, translates to "steel." Over the intervening four centuries, the meaning of this term has been refined so that today it denotes not simply a hard white metal, but a specific range of alloys containing iron and carbon. 

This recipe and a few others in the book show the breadth of Neri's experience in arts other than glassmaking. It is a conclusion greatly amplified by a perusal of his other manuscripts on alchemy and medicine. There is good evidence that our priest was a voracious reader, however he was also quite cautious about repeating techniques only after he had verified them personally. Besides, artisans never wrote down much of this knowledge – only passed in confidence between trusted parties – since, in a very concrete way, superior knowledge represented a competitive advantage over ones rivals. Even if Neri was in the business of divulging secrets, it is safe to assume that many of the artisans and craftsmen he interacted with were decidedly not. 

Two centuries before Neri, the beginning of the fifteenth century saw the invention of moveable type printing in Germany, but also the mastery of perspective illustration in Italy. The contribution of printing to early modern science is well documented, less obvious is the role playerd by artists and perspective illustration. Moveable type made possible the mass production of books; what did get committed to paper now stood a much better chance of survival and transmission. Perspective illustration played a more nuanced role, one that ultimately brings the convex mirror back into the discussion.

In Venice and especially in Florence (Neri's hometown), perspective drawing became the rage among artists, largely due to the Italian translation of a book entitled Deli Aspecti, or "Alhazen's Book of Optics." Suddenly, paintings were made to look three-dimensional, with a realistic sense of depth to them. The new techniques were largely kept in Italy, but interest spread across Europe. Patrons placed great value on work depicting scenes in correct perspective, and in excruciatingly accurate detail. 

Jan van Eyck
The Arnolfini Portrait (detail).

In Flanders, in 1434, Jan van Eyck produced "The Arnolfini Portrait," (above). Behind the main subjects, hanging on the wall is a convex mirror. The reflection in the mirror shows the backs of the two subjects, but also two other figures further back, one of which is thought to be the artist himself, and beyond him a strong light source. The image in the mirror is distorted exactly as one would experience in real life. 

There is growing speculation that among the secrets of "realist" (or naturalist) painters was a growing arsenal of optical tools and lenses used to map out and understand the attributes of perspective. The mirror, in the Arnolfini Portrait was a sort of boast of the artist's proficiency in recreating reality on the canvas.

The point is that here is a case where art led science into new realms. Painters started to take great pains in reproducing reality "as it is" on canvas. Soon minor experimenters like Neri and major luminaries like Galileo were taking great pains to do the same. They strove to observe nature "as it is," not as was prescribed in ancient texts, or dictated by authority. Once that process started, awareness of the world grew and there was no turning back.

Finally, it is amusing to note that in his many manuscript illustrations, Antonio Neri himself never quite mastered perspective drawing, although he did try.

Wednesday, January 15, 2014

A Painterly Inclination

The Conversion of Mary Magdalen
Reverse painted glass
French (?) 1660-75
The seventh and final part of Antonio Neri's 1612 book, L'Arte Vetraria, contains miscellaneous recipes, a number of which are devoted to making paints. Initially, this might seem an odd choice of subjects for the first printed book devoted to glassmaking. We think of fine artists of the seventeenth century working on fresh plaster, on wood panel covered in gesso, or on canvas – the medium that had recently become the new favorite for oil painting – but not on glass.  

On second thought, painters did labor over stained glass windows destined for churches, and any number of smaller glass objects were decorated with paint. To be clear, glass "painting" could take two forms; the first, enameling, was done with pigments that could withstand furnace temperatures, a subject Neri covers in the sixth part of his book. A finished glass object or pane was decorated and then fired a second time either in a furnace or over an oil lamp, Neri specifically mentions his "good friend, Mr. Niccolò Landi," as an expert in this technique. The second form of glass painting is our current focus. This involved traditional paint pigments, which were applied cold and not reheated. These were available in a wider range of colors, but are less permanent. 

This second technique was applied to vessels that contained holy water, delicate "cristallo" showpieces, perfume bottles and a range of ornamental trinkets. The enhancement of glass objects with brushwork was traditionally a female occupation. Glass factories employed teams of women and girls to decorate finished pieces. "Reverse" painting is a technique that dates to the middle ages, in which a picture is built up by applying paint to the back side of a piece of clear glass. In the hands of a talented artist, quite refined images were achieved with this method.

In his book, Neri shows how to extract the color of common flowers to make a variety of pigments called "lakes." He shows two different methods. In the first, he uses the example of broom flowers to make a yellow pigment, the flower petals are gathered and steeped over a low fire in a solution of glassmaker's soda and lime. After a time the color transfers into the liquid. "You will know this [state] when you take the flowers out and see that they have turned white, and become thoroughly uncolored, and the lye is as yellow as a fine Trebbiano wine."

The liquid is moved to glazed terracotta pots and boiled. Alum is added until no more will dissolve, which forces the pigment out of solution. 
[T]hen remove it, and empty the lye into a vessel of clear water. The yellow color will settle to the bottom. Leave it to rest, and then decant off all the water. Again, pour more fresh water over it, decant again and let it rest. As before, the dye will go to the bottom. This way, you will extract all the lye salts and the dose of alum out of the dye.
Finally, the pigment is collected and dried, ready for use.

In the second method, the flower petals are packed into an alembic and saturated with grappa – the strongly alcoholic distillation of white wine. As the alembic is heated the grappa extracts the color from the petals.

These methods emphasize Neri's broad experience and the cross pollination that took place between the various arts. It is not clear if he learned these techniques in Florence, or in Antwerp (or Rome or Venice for that matter); none of these cities had a shortage of talented painters, and Neri must have crossed paths with them. Where there were painters, there was a demand for pigments and for the knowledge to produce them. Even as a twenty-two year old, freshly ordained Catholic priest, Neri exhibited the signs of his own instruction in drawing and watercolor. His earliest manuscript on alchemy is replete with color illustrations, perhaps the very colors he teaches how to make in the glass book. 

Monday, January 13, 2014


Perfume and pasticche from the
Farmaceutica di Santa Maria Novella
In Florence, the followers of St. Dominic ran a well-known apothecary on the grounds of the main Dominican church in Florence, Santa Maria Novella. Started in the thirteenth century, the monks of this order became famous for their knowledge of “simples” or herbal medicines, made from the plants they grew in the large garden adjacent to the monastery. The production of rosewater dates to 1381. The monks ran a small infirmary to care for the sick in their own ranks as well as for the poor. At the suggestion of Grand Duke Cosimo II, they opened a public storefront in 1612, the same year Antonio Neri’s book on glassmaking was published. The man they put in charge of the newly renovated facility was Angiolo Marchissi, a twenty year old friar who was already an “expert,” charged with the formidable task of turning a distillery of herbal remedies into a full blown apothecary. Marchissi was given this responsibility at about the same age, perhaps a bit younger, that Neri was when he began his work at the Casino di San Marco. Although the educational details of both men are unknown, there can be little doubt that their expertise was gained through some sort of organized education in the alchemical arts. An education that was both sophisticated and practical.

The venerable Farmacia at Santa Maria Novella is still in operation today, after four centuries, near the main rail station on Via della Scala, offering soaps, perfumes and ancient herbal remedies. Now in private hands, it is a space that recalls the grandeur of Renaissance opulence under high arched ceilings. Part chapel, part chemist and part museum, great cupboards line the walls still holding century’s-old ceramic and glassware; the vials and beakers used to extract herbal potions by the monks in centuries gone by. The techniques used by apothecaries were often identical to those used by alchemists and they supplied alchemists with many of their raw materials. Less well-known is the public apothecary that was also run by the Dominicans at Piazza San Marco, across from the front entrance of Don Antonio’s Casino where Antonio Neri practiced alchemy and made glass. This apothecary was in the same complex as the monastery and convent of the church of San Marco. The back room of this storefront housed the monks “fonderia,” where medicinal concoctions were manufactured, sometimes using the herbs grown in the botanical gardens around the corner. Like many other apothecaries around Florence, the Farmacia di San Marco served as a popular meeting place for artists and intellectuals.

Tall stone tablets set into the wall outside the front door still list the products made by the monks at San Marco. In general, a sixteenth or seventeenth century apothecary dealt in medicinals, however, their inventories extended to all sorts of chemicals: including pigments used for artists paints, alchemical supplies and many of the raw materials used to color glass. At the turn of the seventeenth century, the facilities at Santa Maria Novella and San Marco were regular suppliers to the Medici and had created special fragrances for the Grand Duchess. As a practicing doctor and Grand Duke Ferdinando’s own physician, Antonio Neri’s father, would have been acquainted with these monks. This farmacia employed Fra Anselmo, who was the brother of royal apothecary Stefano Rosselli. It is not at all unreasonable to speculate that the monks at the Farmacia di San Marco were familiar to Antonio Neri as well as his father. The young priest would soon be working across the street at Don Antonio’s Casino. Finally, Neri’s good friend Emmanuel Ximenes from Flanders had an uncle by the same name who was a monk at Santa Maria Novella.

Friday, January 10, 2014

Glass as Pasta

Paste gem and gold finger ring
Museum of London, 1600s
Antonio Neri devoted the fifth part of his book on glassmaking, L'Arte Vetraria, entirely to the production of "paste gems." These are pieces of intensely colored brilliant glass crystal used to imitate gemstones. The name "paste" comes from the way they were produced. A finely ground powder, resembling pasta flour, was mixed wet in small batches like dough. The mixture starts with crystal clear pieces of quartz rock crystal. Neri "dresses" them by chipping off any impurities or dirt. He then repeatedly heats the quartz in a covered crucible and then dumps it out into clean cold water, which causes it to fracture into smaller and smaller pieces. He advises doing this at least twelve times, stressing the importance of keeping out contamination, avoiding embers and fly ash, which require a clean burning fire.

Next, he works the fractured quartz, which should "crumble and decompose like refined sugar." He grinds it on the porphyry stone with a muller to reduce it to the finest powder; "like sifted grain flour. […] Grind it one time, grind it again and then make another pass. Always put only a little onto the porphyry, which is to say half a spoonful at a time." In another part of the book, Neri recounts a glassmaker's proverb which is apt for this process: "A fine sieve and dry wood bring honor to the furnace."

He mixes in a quantity of "minium" which is an orange or red mineral consisting of lead oxide. This material acts as a "flux," which dramatically lowers the melting temperature of the quartz, and at the same time creates the highly refractive "fire" for which gems are known. In an improvement to this "standard" way of making paste gems, Neri substitutes "Sugar of Saturn" –what we know as lead acetate. This is a water soluble (and highly toxic) lead compound which can be produced in the laboratory, in an extremely purified state. Chemically, minium and lead acetate will reduce the same way in glass; the advantage of the latter is in its higher purity. 

The last part of the formula is to mix in various pigments to give the glass the characteristic colors of different gems. Neri uses "zaffer" (cobalt oxide) for sapphires, copper for emeralds, etc. He presents a number of possibilities, even using real gems as pigment. He also gives advice of how to achieve the correct level of tint for different applications:
Be aware that the colors for the pastes described above can be made more or less saturated according to your will, and inclination, and according to the works in which they will be used. In order to make small stones for rings, the color must be deeper, for larger stones use less color, for earrings, and pendants, concentrate the color. Remit this matter to the discretion of whoever is doing the work. There are no true rules here; the rules given by me above serve only to illuminate the intellect of the curious artisan. To this end, you can always invent and find better colors than the ones that I describe here, other than verdigris, zaffer, and manganese. The curious and noble spirit will be able to get a marvelous red from gold, yet another beautiful red from iron, a most beautiful green from copper, a golden yellow color from lead, a celestial one from silver and a sky blue even more beautiful from the garnets of Bohemia. You will find the small garnets inexpensive, and you can extract their tincture, as I have done many times in Flanders. These materials result in notable effects, and you may do the same with rubies, sapphires, and other gems. All of these things are manageable by a practical chemist. To require me to write such things here would be too much of a tedious matter, especially since I wish to speak succinctly in the present work. However, with the colors described above, you can make very appealing pieces.
The mixed "pasta" is dried and loaded into small terracotta pots, covered with a lid, and sealed shut with a special mixture of clay called "lute." Many of these pots can be prepared and fired at the same time in a pottery furnace. The pots are fired continuously for twenty-four hours or longer. They are allowed to cool slowly, along with the furnace. The lid is then unsealed and lifted very carefully: 
Because it is such a significant matter, I will repeat once more, that when the pastes are not cooked or purified enough, you should return them to cook again in the same crucibles, taking care not to break them. If the pastes are not satisfactorily cooked and purified, putting them into other crucibles will cause many impurities to form. They will have adhesions from the crucibles, and be loaded with dirt; they will be useless, and not usable for any work. When they are not cooked or purified well, then you should not break the crucibles in any way, but re-lute and return them to the furnace or kiln to cook again. Then they will become pure, and beautiful, to be used in any kind of work that you might want to make.

Wednesday, January 8, 2014

Lost and Found

Medici Archives, Florence.
Antonio Neri is best remembered for his seminal 1612 book, L'Arte Vetraria, in which he presents an extensive set of recipes for making and coloring glass. Less known are his writings on the subjects of alchemy, chemistry, natural philosophy and herbal medicine. 

In addition to the glass book, there are five other known works by Neri, and an additional six which have not been found. This makes, in total, twelve distinct works attributed to the priest. Of the writings we can lay our hands on, one is an illustrated manuscript for a book on alchemy that was never published; he called it Treasure of the World. Another includes medicines and other preparations. Two works are devoted to chemistry and the final item is a copy of a letter sent by Neri in Antwerp to a friend in Florence, the subject of which is also medicine. 

These known works are listed below; the glass book is available at numerous libraries, and as contemporary reprints. Treasure of the World and the work titled A, B, C…F reside in the Glasgow University Library, Special Collections (Ferguson 67, 168). Two short manuscripts, both discussing chemistry and natural philosophy (Discorso and Ragionamente), are held by the National Library of Florence (BNCF: Ms. Palat., Serie Targioni, II). The letter to a friend is at the Biblioteca Marciana in Venice (BNMV: Ms. Ital., IV. 60 [5097], no. 5, f. 389r):
  1. L’Arte Vetraria (Florence: Giunti, 1612).
  2. Il tesoro del mondo (Treasure Of The World, 1598–1600).
  3. Book designated A, B, C, D, E, F (c. 1613).
  4. Discorso sopra la chimica (Discorse on Chemistry, 1613).
  5. Ragionamento dell’arte chimica (Rational Of The Art Of Chemistry, 1613).
  6. Letter to a friend (1608).
Among the found items, there is still much work to be done; Treasure Of The World is spectacularly adorned with sixty-one ink and watercolor illustrations. The manuscript contains 175 recipes yet to be deciphered. Among them are various preparations,  including the production of artificial ruby, as well as apparatus for producing the fabled philosopher's stone. The book designated A, B, C…exists as a full manuscript in Glasgow, although in poor condition, and in Florence as "extracts"; these two versions have yet to be compared to each other and to the thousands of pages recorded by Neri’s assistant, Agnolo della Casa. The Glasgow version contains an insert titled "Techniques Copied from an Old Book Here in Pisa." The same page is dated 26 January, 1613. Discorso was published recently by Maria Grazzini (Nuncius, 2012) with correct attribution, after it was plagiarized in 1670 by Jesuit Francesco Lana Terzi. In the letter to a friend, Neri tells of "curing sickness," in accordance with Paracelsan doctrine, "to the great astonishment of Antwerp." 

Of the six items which have not been found (listed below), one is a set of letters and the others are manuscripts or pamphlets of which we have little more to go on than titles. Historian Luigi Zecchin identified a set of twenty-seven letters sent to Neri by his good friend Emmanuel Ximenes, from the contents of these and their dates, he estimated twenty-three to twenty-six letters that Neri must have written to Ximenes. Two items (Herbarium and Opuscula duo) are pamphlets which were recorded in an inventory of Ximenes' library in Antwerp, after the death of his wife in 1617. Two further items (Recettario and Medicamenti) were recorded in an inventory of Don Antonio de' Medici's library in Florence, at the Casino di San Marco, after his death in 1621. The final item (Materia) was found among the possessions of Don Antonio's son, Sig. Giulio Medici, after his death in 1670:

7.  Neri’s letters to Emanuel Ximenes (1601–1611?).
8.  Herbarium Antonii Nerii Pavodetensis (Herbal Tranquilizers ?).
9.  Opuscula duo, unum de chimiis et naediis alter P. Antonii Nerii.
10. Recettario chimico (Book Of Chemical Recipes).
11. Medicamenti di Prete Antonio Neri (Medicaments).
12. Materia di tutto il composto di Prete Antonio Neri.

2014 marks the four-hundredth anniversary of Antonio Neri's death. There is still so much yet to learn about this fascinating character living on the cusp of early modern science.

For more on the works of Antonio Neri see Pieter Boer and Paul Engle, “Antonio Neri: An Annotated Bibliography of Primary References”,  Journal of Glass Studies, v. 52 (2010), pp. 51-67.

Monday, January 6, 2014

The Kabbalah

Kabbalistic Sephiroth Tree,
from Portae Lucis, Paulus Ricius (Trans.)
Augsburg, 1516.
Kabbalah is a form of mysticism practiced within the Jewish tradition. In the early seventeenth century, there was a great deal of interest in Kabbalistic teachings among Catholic alchemists and natural philosophers. It was recognized that Christian alchemy had its roots in Hermetic and earlier Arabic societies, (the word "alchemy" itself is of Arabic origin.) It was thought that the Jewish Kabbalah was yet another branch of the same traditions of relaying secret knowledge by word of mouth. 

In early modern Florence, Italy, there were some interesting connections between the Kabbalah and glassmaker, alchemist and Catholic Priest Antonio Neri. Here is Neri’s own description, of Kabbalah in his 1613 manuscript Discorso

Some call it Kabbalah: in ancient times fathers communicated it to their children only by voice, preserving [this knowledge] for posterity, not for history, but as simple tradition. Others finally gave it the name of ‘wisdom’ [sapienza] because they rightly believed it was impossible, without this art, to know perfectly the nature and the qualities of natural bodies. In order to achieve the end they wanted, which was the perfection of the bodies, they separated the pure from the impure through various chemical operations, which can all be reduced to six principal phases.*

He goes on to describe basic chemical operations that were thought to be fundamental to purifying materials, and ultimately to the production of the Philosopher's Stone. These techniques are the same as practiced in Christian alchemy, and Neri uses them in his glassmaking recipes. Clearly, he had more than a passing knowledge of the subject, and it is interesting to speculate on how he might have come to learn about Jewish alchemical traditions. 

Early seventeenth century Florence contained a city within a city: the Jewish Ghetto. A walled perimeter encircled what is now the Piazza della Republica. This was the mandated home for all of Florence's Jewish population. Each night, entrance gates were closed and locked from the outside. Within the Ghetto, residents were allowed to live and warship freely, even maintaining a Synagogue. In the daytime, the gates were opened, and residents were allowed to go about their business and leave the city with special passes. Among the Ghetto's most prominent residents was the family of alchemist Benedetto Blanis (c.1580-1647.) Blanis served as librarian to Medici prince Don Giovanni. Giovanni maintained an alchemical laboratory in his residence, which was run by Blanis, located only a short distance from where Antonio Neri was living when he first worked at the Casino di San Marco.  

Don Giovanni maintained a close relationship with Neri’s benefactor Don Antonio de' Medici. So close, in fact that when two of  Blanis' relatives were implicated in a gambling scheme, Don Antonio hid them at his residence and then spirited them away, out of Florence, in his own coach until matters cooled off. Furthermore, Blanis came from a family of doctors who must have been known to Neri's father, royal physician to Grand Duke Ferdinando. Antonio Neri was probably a couple of years older than Blanis, if they did not meet through mutual connections with the Medici family, then perhaps they met on the street. The walk for Neri, between his living quarters near Santa Trinita, and the Casino laboratories would have passed around or through the Ghetto, and the walk for Blanis to Don Giovanni's palazzo on Via Parione took him past Neri's front door. The paths of the two men may have crossed, but there is not direct evidence.

Of course, in the absence of hard facts, there are many other possibilities of how Antonio Neri might have become acquainted with Kabbalistic tradition. By taking a look at Blanis and his connections to the Medici family, we can at least see an area of cooperation between Jewish and Christian alchemists in what we might otherwise assume to be an inviolable separation. 

* “Discorso sopra la Chimica: The Paracelsian Philosophy of Antonio Neri”, M.G. Grazzini / Nuncius 27 (2012), p. 337.
For more on Blanis, see Edward L. Goldberg, The Secret World of Benedetto Blanis. (2011).

Friday, January 3, 2014

Ferdinando’s Wedding

Orazio Scarabelli (1592)
1589 Naval Battle In The Courtyard Of The Palazzo Pitti.
In 1589, when Antonio Neri was a thirteen-year-old boy, he experienced a rare event, the wedding of a sitting grand duke. Newly crowned, Ferdinando I de' Medici, was married to French princess (and distant Medici relative) Christina of Lorraine. In a deliberate show of political and family strength, the entire city of Florence was turned into the venue for a celebration of unprecedented magnitude. No expense was spared; the city and its people were swept into an extended state of pageantry extending from late March to early May. Among the celebratory events were concerts, competitions, recitals, exhibitions and fireworks. Grand spectacles such as indoor mock naval battles (naumachia) thrilled guests. Manned scale ships sailed in the flooded Pitti Palace courtyard, covered by an enormous tent. Guests were invited to attend from royal courts throughout Europe. The grand wedding events served notice of Ferdinando’s arrival on the political scene.   

As superintendent of the workmen at the Uffizi, artist Jacopo Ligozzi probably oversaw the production of glassware for the wedding banquets. The furnace had been built twenty years earlier in 1569 by Muranese master Bartolo d'Alvise. By special arrangement with the Venetian authorities, Bartolo and two assistants were granted permission to relocate from Murano to show Florentine craftsmen the secrets of making "cristallo," the coveted glassware for which Venice had become famous. Bartolo was awarded the exclusive right to produce and sell Venetian style glassware (façon de Venise) in Tuscany. He stayed until about 1583, leaving the city when Antonio Neri was around seven years old. Presumably, at the time of the wedding, the furnace was being run by the Florentines, perhaps with some continued assistance by the Venetians (officially or not).

Right around the time of the wedding festivities, Antonio Neri's father was given a great honor; Neri Neri, as he was called, was appointed to the position of physician to the grand duke and his entire family. It is hard to understate the importance of becoming such a trusted member of the royal court's inner circle. The appointment must have been the cause of great celebration within Antonio's family. It was the crowning achievement of an already successful medical career. Almost a decade earlier, in 1580, Neri Neri had been granted citizenship along with his own father, barber surgeon Jacopo Neri. In Tuscany, citizen status was an honor conferred to a small fraction of the population and often through inheritance at around the age of thirty. The fact that Neri Neri gained citizenship at the age of forty and did so together with his father shows it was not a legacy, but perhaps their medical prowess that lead to the award. Citizen status bestowed the advantage of direct representation in the government and the right to hold public office. It also carried responsibilities to the city, to its leaders and to the Church. 

While 1589 started with great excitement and celebration for the city and for the Neri family, it ended on a more somber note, with the unwelcome intervention of Mother Nature. In the fall of that year, the Arno River overflowed its banks, and flooded much of the city, including Borgo Pinti, the street on which the family lived. Florentines were conditioned by long experience to keep living quarters and valuables above the ground floor; it not only protected against flood damage, but earlier in the cities history, against attack and looting in times of war. Nevertheless, the flood of 1589 was a bad one. Although specific details are not available, it is known that nearby Santa Croce church was devastated. This flood is listed among the most extreme in the city's history, along with the flood of 1966, when waters inside the Neri palazzo reached two meters (over six feet).

Wednesday, January 1, 2014

Old Friends Not Be Forgot

Giacinto Talducci (della Casa)
Justus Sustermans
Jacinto Talducci was among the many interesting characters who worked in Florence at the alchemical laboratory of Medici Prince Don Antonio. Today, the Casino di San Marco still stands, serving as an appellate courthouse, next door to the San Marco church complex in the north end of the city. In the first decades of the seventeenth century it was the personal residence of Don Antonio de' Medici, and housed the alchemical laboratories that came to be known as the "Real Fonderia" (Royal Foundry). Here, behind unassuming walls, was where medicines, elixirs and various chemical reagents were manufactured at the turn of the seventeenth century. Visiting dignitaries were often given as gift packages containing curatives for various ailments. This was also where Antonio Neri first made glass for the ruling family. 

As children, according to historian Giovanni Targioni-Tozzetti, Jacinto Talducci and his older brother Ottavio "learned alchemy at the knee of Don Antonio." Ottavio's Florentine birth record shows he was born in 1596 and although a record for Jacinto has not been found, indications are that he was born in 1601. The boys' father Filippo Talducci della Casa bought a house just south of the city walls in 1598 where they may have been raised. Other family members were also working at the Casino in this period. Don Antonio's biographer Covoni lists Giovanni Talducci as a "fenditore" at the facility. An alchemist named Alessandro Talducci della Casa wrote a tract around the turn of the century and in it he passed on the coveted yet dangerous recipe for "the duke's oil," a pure distillation of nicotine. Antonio Neri's own disciple, who documented thousands of pages of Neri's experiments, was Agnolo della Casa from the same family.

When Antonio Neri returned to Tuscany from his seven year sojourn in Flanders, he settled down to write the book on glassmaking, L'Arte Vetraria, which would eventually make him famous. He dedicated the volume to his benefactor, Don Antonio: 
In all consideration, it is my proud duty to dedicate this book to none other than you, most Illustrious Excellency; for you have always been my outstanding patron. You are a gifted leader in this and in all other noble and worthy developments made continually in all the arts. This is the essence of a true and generous Prince.
If the Talducci boys did indeed learn alchemy at Don Antonio's knee, there is every chance that they had the opportunity to meet Antonio Neri upon his return to Florence. They would have been ten and fifteen years old, certainly old enough that they would have remembered the author. Indeed, historian Francesco Inghirami recorded that after Antonio Neri's death in 1614, Don Antonio left no stone unturned in looking for the priest's secret of transmutation:
Don Antonio was not quieted and he questioned all of Neri’s friends to see if he could find the information, but his efforts were in vain, as they should be in so groundless a science, although Giacinto Salducci said that he had seen great things, specifically a powder that fixed mercury into gold.
Targioni-Tozzetti chronicled that after Don Antonio's death in 1621, these boys would go on to serve Ferdinando II de' Medici (grand duke from 1621 to 1670).  The Casino laboratories of the Royal Foundry were moved to the Boboli Gardens. Ottavio would become its new director, while Jacinto became the parish priest of San Pietro Church, a few kilometers east of Florence in Sorgane near Bagno a Ripoli. When Ottavio died, the grand duke called Jacinto back into service as the new director of the Royal Foundry under Francesco Redi. 

There is one final twist of history that ties Neri to Talducci:
The foundry of S.A.S.  received some unnamed chemical medicines, which were found among the belongings in the in-heritance of Sig. Giulio Medici; things that were handled in the foundry of His Excellency Don Antonio Medici and made a long time ago, about 60 years, not subjects likely to be of any good, yet among them there was a booklet, entitled: Material of all the compounds of Priest Antonio Neri; there is a red dustcover, which says ‘experiments’ above the unknown sign [*]. Furthermore, I received some other written pages, dealing with the work of Priest Neri, metaphysically confused writings and of little help, these received and sent to the Marquis Cerbone Del Monte  by order of the Grand Duke. This the 30th of August, 1670.  -Iacinto Salducci  
Jacinto Talducci died in 1700, at the age of 99 (Targioni-Tozzetti, quoting Francesco Bonazzini). He was the last surviving member of Don Antonio’s band, spanning a full century in alchemy.

* The unknown symbol: