Encomium to a Female Glassblower

Woman flameworking glass
(Attribution Unknown, late 19th cent.)

In 1743, Britain was ruled by George II, although the Jacobites in Scotland were plotting to install Bonnie Prince Charlie to the throne. That year, Samuel Johnson was a 33 year old struggling writer and his still-to-be famed biographer James Boswell was just a toddler in Edinburgh. Also in Edinburgh, in 1743, exhibiting for a short time only, was Mrs. Johnston, an itinerant fancy glassblower.

‘Fancy' glassblowing refers to the process of working, not at a furnace, but at a table over an oil lamp with rods of glass. The artist formed the glass into small objects; rigged ships, animals, flowers, religious icons, beads and other ornaments. Glass spinning was a related process in which the heat of the lamp flame was used to draw an extremely fine continuous filament of glass that was collected on a large spinning wheel. The result was a mass of almost silk-like floss that was soft and flexible; nothing like the brittle glass of a cup or a window pane. Spinning demonstrations never failed to fascinate audiences and were a staple of fancy glass blowing acts well into the twentieth century.

Artists would often take suggestions from spectators on what to make and then form the piece on the spot. A common technique was to repeatedly touch a thin rod of glass, called a stringer, along the piece under construction forming a series of little loops in the flame. Rows of loops build up a surface that resembles knitting and a skilled artist can form finished pieces quickly. Eventually, both spinning and the knitting techniques became known generically as ‘spun glass’.

Although not well chronicled, this type of demonstration was performed at fairs and other shows as far back as the fifteenth century, and probably earlier. Because of their popularity with women and children, female fancy glass workers were not only well accepted, but commanded a premium at these events.

Below is a lovely correspondence appearing in the local Edinburgh newspaper in January of 1743. The writer is so taken by Mrs. Johnston’s demonstration that he or she was moved to compose a poem. In terms of documenting eighteenth century glass artists, it simply does not get any better:

“To The Publishers of the Caledonian Mercury. Reading a former letter of Leonora’s, curiosity inclined me to see Mrs Johnston the glass spinner, and was agreeably surprised to find the encomiums given her fall short of the character she justly deserves; so I hope the gentlemen, as well as the ladies, will solicit in the behalf of the celebrated artist, as is due her merit.  Therefore,

Let Britain quite enjoy its transport round,

Or Johnston’s praise to all the nation sound;

For me, to humble distance I’ll retire,

There gaze, and with secret joy admire:

My native Scotland such a one can boast,

On whom the praises of the world are lost,

For her own works do justly praise her most.

By giving this a place in your paper, you will oblige, yours, etcetera  -- Torisment. [1]

Two weeks later, appearing in the same paper is Mrs. Johnston’s reaction:

“When a person is obliged to persons unknown, the best way is to return them thanks in the most public manner: therefore Mrs. Johnston, the glass blower and spinner, returns thanks to all the gentlemen and ladies who have honored her with their presence; but more especially the gentleman and lady who did her that honour in the public paper: She cannot show her gratitude in any other way than by her best prayers for their felicity, which she shall always think herself to do both for them and all other her benefactors. Her stay being short in this kingdom, she performs now for the small price of sixpence per piece. [2]

[1] The Caledonian Mercury, Edinburgh, Scotland, 10 Jan 1743, p. 3.

[2] Op. cit., 24 Jan 1743, p. 3.

A Glassmaker's Birthday

Relief portrait of Antonio Neri,

artist unknown, La Specola Museum,

Florence.

Alchemist, Glassmaker, and Priest Antonio Neri was born in Florence, Italy on 29 February 1576. From his baptismal record, we know the exact time of birth: "three hours and 25 minutes past sunset." In terms of current timekeeping conventions, sunset occurred on that particular Thursday at about 6:15 pm (local time) so the big event happened at 9:40 pm.

It might seem a bit odd to have such accurate records -- almost as if an astronomical event were being recorded. Actually, that is exactly what was being done; astrology of the sixteenth century drew a strong correspondence between 'macroscopic' events in the heavens and more earthly matters. To have an exact time of birth was seen as a way to gain greater insights into the events of ones personal life and to plan in a way that was more in harmony with the natural order of things.

Of all the days to be born, 29 February was considered among the least auspicious. A dire Northern Italian folk proverb states "An bisesti, o la mama o 'l bambi" predicting that, born on this day, a child or its mother was fated to die by year's end. Indeed, the Italian word naming the day, bisestile, had become a synonym for misfortune or calamity and is still the case for the French cognate bissêtre. Whatever stock the family put into ancient superstitions, happily this prophecy did not come true for Dianora or her fourth child Antonio.

Although his was a February birth, it was perhaps not as deep into winter as one might assume. Due to a discrepancy in the Julian calendar, which was in force then, the Spring equinox of Neri's birth year happened much earlier in the calendar than today, around 10 March, in fact. 

Infant mortality was not uncommon and for a child to die unbaptized only magnified a family's trauma. Church theologians had debated since the fourth century on the fate of the souls of such children. Most Catholic families baptized infants as soon as humanly possible, in Antonio's case the very next morning. Births occurring within Florence were officially registered at a central baptistery, San Giovanni, the ancient octagonal basilica standing directly in front of Florence's main Cathedral. 

The full baptistery record, in translation, for Antonio Neri reads:

Thursday, 1 March 1575:  Antonio Lodovico was born to Mr. Neri di Jacopo and Dianora di Francesco Parenti, residents of San Pier Maggiore parish. The time of birth was 29 February, at 3 hours 25 minutes past sunset. The godparents are Francesco di Girolamo Lenzoni and Ginevra di Federigo Sassetti.

The year is recorded as 1575 because in those days, Florentines celebrated the New Year on 25 March. Today we consider January, February and March to be part of the new year. 

Antonio joined a growing family that already contained siblings Lessandra, Jacopo and Francesco, and later would number ten children.  His father was thirty-six year-old Neri di Jacopo Neri, (Neri Neri to his friends) and his mother was twenty-one year-old Dianora Parenti. Neri Neri was a prominent doctor and later was appointed to be the personal physician to Grand Duke Ferdinando. Dianora was the daughter of Francesco Parenti, Michelangelo's lawyer. 

Tradition dictated that births were celebrated with a house party open to friends and neighbors. Thirty-four year-old Francesco Lenzoni, Antonio's godfather, would certainly have done his best to attend. His family included Florentine senators and Francesco himself would later become Tuscan ambassador to Spain. Godmother Ginevra Sassetti, in her late fifties, was also from a prominent family. Her nephew Filippo would send plant specimens back from India to be inspected by Neri Neri and their mutual friend Baccio Valori who would become director of the Laurentian Library in Florence.

Antonio Neri, would go on to learn the finer points of alchemy and glassmaking, developing new formulas and techniques that would be applied throughout Europe. In 1612, he published the world's first book entirely devoted to formulating glass, L'Arte Vetraria. It seems especially appropriate that we pause and raise a toast (in glass, of course) to his accomplishment and to the end of February, looking forward to warmer days ahead. Buon compleanno Antonio!

A Cardinal's Ceiling

From "Tesoro del Mondo" (Treasure of the World)

Antonio Neri 1598-1600

In the years 1598-1600, newly ordained Florentine priest and alchemist Antonio Neri was hard at work on a manuscript which he titled Tesoro del Mondo (Treasure of the World). [1]  One illustration near the front shows an allegorical map in which six roads all lead to the Vatican at its center. A Latin inscription translates as, "The different ways to Rome" followed by "Qui pot[est] capere capiat" or 'He that can take, let him take it.' Taken in context, this Biblical reference ( Matthew 19:12) apparently refers to the various alchemical 'paths' leading to the philosopher's stone, but the choice of imagery suggests that Neri spent time in the city of seven hills. [2] It is a tantalizing clue to his travels, although there is no direct confirmation. 

If Rome did figure in the young Neri's itinerary, a visit to Cardinal Francisco Maria Del Monte would have been de rigueur. The Medici family ruled Neri's home region of Tuscany and Cardinal Del Monte was the Medici's informal ambassador in Rome. He was a dedicated patron of the arts, an amateur alchemist, a collector of glass and a trusted successor to Grand Duke Ferdinando in the College of Cardinals. More significantly, he was a close friend and advisor to Neri's sponsor Don Antonio de' Medici ever since that prince was a child.  Del Monte's biographer Zygmunt Waźbiński offers, "It is very likely that Cardinal Del Monte, with his interest in glass, had known then (in 1598) the [future] author [Neri] of L'Arte Vetraria." [3]

Michelangelo Caravaggio, c. 1597
Casino Ludovisi.

As the sixteenth century ended and a new one dawned, Del Monte sheltered the rough-and-tumble painter Michelangelo Caravaggio, whom he set up with an in-house studio and an allowance. However, in 1606, the master of Realism fled Rome after reportedly murdering a tavern waiter over a tennis wager, but not before executing his only known fresco on the vaulted ceiling of Del Monte's own alchemy laboratory. Looking out over Rome, on the panoramic Pincio, in the Villa that later became the Casino Ludovisi and is now known as the Casino dell'Aurora, Caravaggio put his brush to work. According to early biographer of artists, Gian Pietro Bellori, he executed the oil painting on the vaulted ceiling of the small alchemical laboratory (now a corridor) sometime between 1597 and 1600. [4] Depicted in the mural are the three brothers Jupiter, Neptune and Pluto: the masters of the universe. The image is a double allegory of the three basic chemical substances of Paracelsus (salt, sulfur and mercury) and the four Aristotelian elements (air, earth, water and fire). Jupiter with the eagle stands for sulfur and air, Neptune with the seahorse stands for mercury and water and Pluto with the three-headed dog Cerberus stands for salt and earth. Jupiter is reaching out to move the central celestial sphere in which the sun (fire) revolves around the earth. [5] 

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


[1] Neri 1598-1600, f.xxviii-v.  (see bibliography).
[2] For more on the alchemical interpretation of this illustration see Grazzini 2012.
[3] Neri 1612.
[4] Bellori 1672, pp. 197-216.
[5] Wallach 1975, pp. 101-112.

* this post first appeared in a slightly different form on 4 July 2014.

Turquoise glass

Turquoise glass stamp

of calif Mustadi  c.1170.

It is estimated that turquoise is among the earliest gems ever mined. With colors that vary from pastel green to a bright sky blue, it has adorned Egyptian sarcophaguses of 5000 years ago, 3000-year-old Chinese art, Aztec death masks and the domes of Persian palaces. 

When traders brought it to Europe from the Mideast, it became known as "turks" or "turquoise" after the old French for "Turkish." While it has never been mined in Turkey, the most highly valued Persian stones were imported there and used extensively for trade. Polished pieces were famously mounted on Turkish equestrian saddles, in the belief that the material conferred sure-footedness and protection from injury during a fall.

As one of the first gems to be collected and traded, turquoise was also one of the first to be imitated. Egyptian faience blue is an early forerunner of glass. It is more porous than glass, but it contains all the same ingredients and could be cast into forms that look just like solid turquoise. In the seventeenth century, the genuine mineral and its imitation continued to hold importance. In Antonio Neri's book L'Arte Vetraria, the subject is mentioned several times; he offers one recipe to restore faded stones by soaking them in almond oil. For turquoise colored enamels he presents two different shades. On the subject of glass, he notes that "Sky Blue, or more properly turquoise, is a principal color in the art of glassmaking" and "I have made this color often, because it is very necessary in beadmaking and is the most esteemed and prized color in the art."

To make his imitation turquoise glass, Neri starts with a batch of high quality transparent aquamarine blue, to which he adds a specially prepared variety of common salt. "Add it little by little, until the aquamarine color loses its transparency and diaphany becoming opaque."

Take the sea salt known as black salt or rather coarse salt, since the ordinary white salt that they make in Volterra would not be good. Put this salt in a frit kiln or oven to calcine, in order to release all moisture and turn white. Next, grind it well into a fine white powder. This salt now calcined should be stored for the use of making sky blue or rather turquoise color as described below.

Sea salt is mostly composed of sodium chloride, which is like table salt that we use for food. However, it can include significant additional minerals, as implied by Neri’s description of it as "black salt." Additional elements can include sulfur, potassium, manganese and more. Regrettably, he leaves us with no further clues to its identity, nor does he explain why the recipe would not work as well with the salt available from Volterra. He goes on to advise that the mix should be used quickly, because if left to sit in the furnace, the glass would start to revert to an ugly transparent color. The remedy for this is to add more salt. He finishes with some practical advice for glassmakers about adding salt to molten glass:

The furnace conciatore should take careful note here, when you add this salt, if it is not well calcined it always bursts. Therefore, you should be cautious and shield your eyes and vision, because there is a danger you could be hurt. Add the doses of salt little by little putting in a bit at a time pausing from one time to the next until you see the desired color. With this, I do not rely on either dose or weight, but only on my eyes. When I see that the glass reaches the desired level of color, I stop adding salt. This all comes with experience. 

* This post first appeared her in a slightly shorter form on 9 April, 2014.

San Giusto alle Mura

Window of  Santa Maria del Fiore cathedral,

Florence, Italy.

In Florence, at the very end of the street on which Antonio Neri spent his youth, Borgo Pinti, was the residence and estate of the Archbishop. Beyond were the city walls and the enormous wooden doors of the Porta Pinti gate (115 foot, or 35 meters tall). Just on the other side of the gate, which in Neri’s time was normally closed and guarded, once stood the San Giusto alle Mura monastery, built in the thirteenth century. Despite the similar name, there is no connection between the Ingesuati monks of San Giusto and the modern order known as the Jesuits, which was not formed until 1534 and recognized by the Church in 1540.

The monks at San Giusto were famous for the stained glass windows they made; hence one of numerous theories that the street name 'Pinti' may be a contraction of 'dipinti 'or 'dipintori' (paintings or painters). Using their own glass furnaces, the Ingesuati monks provided windows for the Neri family's church Cestello and for Santa Maria del Fiore among other churches. They also ran an art school and were famous for making the color pigments used by painters, producing a coveted ultramarine blue. Their customers included the likes of Leonardo, Michelangelo, Botticelli, Del Sarto, Ghirlandaio and Filippo Lippi. 

Apparently, the Ingesuati's artistic devotion was not matched by their religious observance. In his Lives of the Artists, Giorgio Vasari recalls the less than complimentary sentiments of the monk's own in-house chaplain, a certain Servite monk named Fra Martino. He notes that the monks do not read Mass, and that they, "do nothing but say paternosters ['our Father...'], make glass windows, distill herbs for sweet waters, dig their gardens, and perform other works of similar kind, but do not study or cultivate letters."

Antonio Neri has a slightly more positive opinion about the value of stained glass windows. In the introduction to L'Arte Vetraria, he waxes poetic: 

Glass is also a great ornament to God's churches since, among other things, many beautiful windows are made, adorned with graceful paintings, in which the metallic colors are so intense and vivid that they seem like so many oriental gems. 

The windows that inspired these lines may well have been made by monks of San Giusto. As a child, Antonio Neri had seen the striking windows in Cestello and in the city cathedral. It would be nice to be able to connect him to the Ingesuati, but in 1529, long before his birth, their entire complex just outside the Pinti Gate was dismantled in defensive preparation for the siege of Florence. The Florentine military cleared away the structures near the outside of the city walls. The monks of San Giusto alle Mura moved to the much smaller Calza Convent on the oltrarno, on the opposite side of town near the Porta Romana gate. They did not rebuild the glassworks at the new location and it is doubtful that any of the glass workers would have still been alive by the time Antonio Neri came of age.

This post first appeared here in a slightly shorter form as "Glass Monks" on 30 September 2013.

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.

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. 

This post first appeared on 16 August 2013.