Solid Water

Photo of Hawaiian waves (c) by Clark Little .

In the ancient world, certain natural materials commanded a premium and rock crystal was among the most coveted. Large completely transparent crystals of quartz were found in caves and glacial moraines and craftsmen managed to work them into exquisite cups, vessels and ceremonial objects. By the time the Renaissance arrived, the demand for rock crystal drove much of the innovation in glassmaking. Indeed, clear glass was very much sought after and thought of as an artificially produced form of rock crystal.

A standard line in the historical narrative tells that the ancient Greeks believed that rock crystal was a form of solidified water, the word “krystallos” meaning ice. Enough written material survives from the likes of Herodotus, Pliny, Seneca and Saint Jerome to know for certain that one version or another of this idea has been around for a few thousand years. It is a line that usually gets attention for all the wrong reasons; when stated so glibly, it does not throw any light on ancient culture or our connection to it and worse, it plays into the fiction that we are somehow very much more astute than our relatives of 150 generations ago, that our progenitors were quaintly uninformed. 

Instead, think of “solidified water” as part of a working model of the world. It was consistent with the prevailing conception of nature in the same way that, for modern physicists, eleven-dimensional string theory serves; it seems to be correct, to the best of our knowledge, but the chances are good that there is more to the story yet to figure out. Like string theory, solid water is not a concept that would have a strong bearing on the daily lives of most people. For specialized artisans, it did make good sense; to thinking of rock crystal in this way would be a reminder that if treated too roughly, the material would shatter into pieces as if it were ice.

In the fifteenth century, the Venetian island of Murano became the center of the universe for glassmakers, and it stayed that way for the next four centuries. Of all the many forms that glass can take, the one that made Murano most famous was cristallo; named after the mineral it so closely imitates. The genius of cristallo was in bringing together diverse techniques and ingredients to form a product that was clear like water, yet could be worked thinner and in more complex designs than was possible with carved rock crystal.

 The hallmark of cristallo was the specific use of Levantine soda ash and white quartz river stones (tarso) as opposed to sand and it became the pinnacle of the glassmaker’s art. For the first time, artisans combine best practices with premium raw material sources, the extra purification steps, the careful avoidance of iron contamination, the hot glass washing process, the clean burning hardwood fire and the manganese color correction. In Venetian furnaces, even the clay for the crucibles was a special product imported from Constantinople, which did not contaminate the melt.

In 1450 the Christian world was dealt a severe blow by the Byzantine Empire’s fall to the Ottomans and with it went the Venetian’s major trading partners. That same year, the Murano glassmaker Angelo Barovier is given credit for the development of cristallo. He was the man responsible for bringing together the ultimate refinements that elevated glass to a new level of perfection and created a national product for Venice when they sorely needed it. These techniques and materials were all available and utilized by glassmakers individually at least fifty years earlier, but not together in a single product. Barovier had attended lectures by noted alchemist Paola de Pergola, at the School of Rialto. This indicates that he was thinking along the lines of a chemist in putting together a repeatable regimen for an exceptionally clear, bright, workable product. Barovier’s innovation would become a tradition that was carried on by countless glassmakers and ultimately by our Florentine priest Neri more than a century and a half later.

In seventeenth century Florence, Grand Duke Cosimo I de' Medici negotiated for Venetian masters to teach and practice their coveted techniques in Tuscany. Royal architect and polymath Bernardo Buontalenti was credited with the development of an artificial rock crystal, Tuscany’s own version of cristallo. It is an open question whether we see his hand in Neri’s recipe number seventy-six in which actual precious rock crystal is crushed and used as raw material for glass. In any case, Buontalenti’s continued presence at the Casino must have been an influential experience for his former pupil Don Antonio de' Medici, Neri’s sponsor. Our glassmaking priest was impressed enough with this technique to use rock crystal as the basis for his artificial gems. In turn, Neri’s chapter on artificial gems received the most attention, by far, of any other single subject in his groundbreaking book on glassmaking, L’Arte Vetraria. His work on this subject took on a life of its own and was the subject of plagiarism and unattributed derivative works well into the nineteenth century. An argument can be made that his lead glass based gems fueled the revolution pioneered by English glassmaker George Ravenscroft in what has become the current pinnacle of clear glass: lead crystal.

A Gift for the Innocent

One of the distinctive roundels designed
by Andrea della Robbia for the facade of the
Ospedale degli Innocenti.

In early 1597, Antonio Neri turned twenty-one. He was in his final year of training for the priesthood in the Catholic Church. The war with the Ottoman Empire in Hungary was winding down and men were returning to Florence from the front lines, among them Don Antonio de' Medici, Neri's future benefactor. At this time, there is no indication of Neri's future activity as a glassmaker, but he certainly had been deeply involved in learning alchemy for several years. It is not surprising since his father was the personal physician to Grand Duke Ferdinando de' Medici and his grandfather was a celebrated barber-surgeon. He probably grew up seeing the chemical arts practiced on a daily basis. 

This same year, Antonio Neri's father, Neri Neri, was commissioned along with three colleagues from the physician's guild to make a complete revision of the Ricettario Fiorentino. [1] This was the physician and apothecary's reference used throughout Europe and in Tuscany it carried the weight of law; every medical professional was required to own a copy and adhere to its prescriptions. The first edition had been published almost a century earlier; it was revised periodically to keep it current with the latest thinking and remedies. 

Reviewing the book's recipes is of course interesting. The final prescription is one for chicken soup, the preparation of which would certainly make most modern patients turn a bit green.  An attempt to look beyond the technical methods is also intriguing; we are rewarded with a glimpse into the personalities of the men who wrote the book. One of the authors in particular has a story that illustrates how shrewd maneuvering can be used for good, even in times when self-serving and corruption were endemic.

The four authors' names do not appear in the book itself, but they are documented in a letter from the college of physicians acknowledging the directive of the grand duke and pledging to purge the text of any preparations that could be dangerous. [2] In addition to Neri Neri and Francesco Rosselli (son of the royal apothecary), the other two co-authors were Giovanni Galletti and Giovan Battista Benadù. [3] Giovanni Galletti, is difficult to pin down. His family resided in Florence and he exchanged letters with a Filippo Galletti in Rome, who may have been a brother or cousin. Adding intrigue to the connection, Filippo was working as a confidential correspondent—read: a spy—for Ferdinando I de' Medici around 1600. [4] The fourth co-author, Benadù, a physician and surgeon from Fivizzano, north of Pisa, died in 1603. [5] His will provided for an annual gift to Santa Maria Nuova hospital [6] and another to the Ospedale degli Innocenti, a gift that amazingly supported the orphanage into the nineteenth century. [7]

Little information exists about these men, it would seem impossible to extract any meaningful insight into their personalities, but perhaps we can take a small step in that direction. Neri Neri's coauthor, Benadù, administered his financial gift to the Ospedale degli Innocenti with a large dose of shrewdness. The measures he took to ensure the purposeful use of his money, even after his death, reveal a man who cared a great deal about the less fortunate. In the 1400s, the wealthy silk merchants’ guild started Innocenti to be responsible for the welfare of abandoned children. By the late 1500s, the orphanage struggled under a mountain of debt. Grand Duke Ferdinando made a concerted effort to improve the situation and it became a well run, efficient institution, although throughout its history, it was not without problems. Over centuries of operation, it had seen the abuse of children and exploitation by both parents and the government. Famine hit Tuscany on a regular basis and less of it was due to natural causes than one might imagine. The grand dukes tended to make large trade deals, with Spain and other states, which depleted supplies and drove the local price of grain beyond what poorer families could afford. In those hard times, the Ospedale degli Innocenti experienced overflows of abandoned children. It was discovered under Cosimo I de' Medici's rule that some desperate families had found creative ways to take advantage. Destitute mothers left their infants at Innocenti, where children were assured of a square meal, a warm bed and an education. The same mothers then sold their milk to the orphanage, in effect collecting a wage to wet nurse their own children.
Florentine accountants invented double entry bookkeeping, and the Medici gave that innovation a good workout. They pioneered the use of municipal bonds, the purchase of which was sometimes made compulsory. At the time, they were a novel approach to fund a city’s development, and selling bonds under the banner of the orphanage was an early bit of marketing genius. It is unfortunate that the money often did not stay with the orphanage, but the obligation to pay off these debts did. The Medici often raided the accounts to pay for other projects both civic and personal. Under Ferdinando, the situation improved, but was far from stable. Through a clever maneuver, Benadù ensured his money went to the orphanage alone and not to bondholders. He left an inheritance for the day-to-day operation of Innocenti, putting control in the hands of the monks at the Badia Fiorentina monastery, where it was beyond the reach of greedy hands.

The 1597 edition of Ricettario Fiorentino produced by Neri Neri, Francesco Rosselli and their colleagues proved so popular that Grand Duke Francesco II [8] ordered it reprinted without changes in 1623. [9]

[1] Neri, Benadù, Rosselli, Galletti 1597. 
[2] Corradi 1887, p. 55.
[3] Giovan Battista di Nicolao Benadù (?–1603), not to be confused with Priest Giovanni Benadù from Lucca.
[4] For more on the Galletti family cf. Crollalanza 1878, p. 222. About Filippo Galletti cf. Zapperi 1994, pp. 50, 71; Liebreich 2005, pp. 67, 281. For letters to Giovanni, see ASR 1591.
[5] He set up a trust fund for his sisters and their female relatives, which was still functioning in the twentieth century. Cf. Arrigoni 1882, p. 34.
[6] Lamioni 1994, p. 530.
[7] Cardini 1968, p. 190. The Innocenti records identify Benadù as both physician and surgeon and his monetary gift played a supporting role in the continued operation of the facility (AOI 1603.) As mentioned above.
[8] Ferdinando II de’ Medici (1610–1670).
[9]  Neri, Benadù, Rosselli, Galletti 1623.

The Purse of Envy Reprise

Antonio Neri, "The Mineral Gold"
Tesoro del Mondo, Ferguson 67, f. 5r.

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

Melani reported that in July 1596, Neri performed a transmutation of base metal into "twenty-four carat" gold. Upon being pressed, Neri confided that he had learned the secret from a German, who performed the gold transmutation with a "tablet of medicine." The German told him the medicine was nothing but the simple quintessence of green vitriol and the method to produce it was described by Paracelsus.[1]

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

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

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

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

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

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

[1]  Galluzzi 1982, p. 53; Grazzini 1983, pp. 214–216. 
[2]  For modern English translation see Theophilus 1979. 
[3]  Inghirami 1841–44, v. 13, pp. 457–458. 
[4]  Neri 1612.
[5]  Grazzini 2012, pp. 329, 356.

*This post first appeared here on 6 November 2013.

Neri's Cabinet #7: Lime

Vintage 1920's Water Glass Label.

The temperature of 1500 degrees (825 C) was comfortably within reach of seventeenth glassmakers like Antonio Neri. It was also achievable in much earlier times and was used in one of the earliest chemical reactions known; the production of "lime" by heating seashells or limestone to the above mentioned temperature. This is the point at which these materials give up the carbon dioxide gas bound into their chemical structure, leaving behind calcium oxide, otherwise known as lime.

What makes lime so useful is a property early Roman engineers knew well; that when mixed with water, lime undergoes a chemical reaction that releases heat and quickly solidifies into a rock-hard mass. The Romans used it as a construction material; they mixed it with ash, clay, sand and stones to form mortar, cement and concrete. It has played a critical role ever since in the construction of buildings, roads and monuments.

Today it is perhaps not an obvious choice in imagining the supplies of a seventeenth century alchemist’s cabinet; lime does not require exotic methods to produce, it was made in industrial quantities and readily available as a construction material. Nevertheless, lime played an important part in many diverse chemical preparations of the day. Antonio Neri mentions it numerous times in his writing. He used it in his lute recipe; a hard, cement like coating which protected alchemical glassware in direct flame and sealed joints. He also used it to extract the color from flowers in the production of paints. Most notably, he used lime as an ingredient in the formulation of glass itself. 

Lime turns out to be a rather critical ingredient in glassmaking and the central player in a mystery about the history of glass that to this day has not been satisfactorily explained. He obtained the white powder from suppliers as "lime cake." Early in his book, L'Arte Vetraria, he states it should be used in all his glass recipes. 

Take lime salt, which is used for building. Purify this salt and mix it with ordinary Levantine polverino salt in the proportion of 2 pounds per 100, which is 2 pounds of lime salt, to every 100 pounds of polverino salt, purified and well made, as previously described. With this salt mixture, you can make yourself ordinary frit, and put it in the crucible to clarify. I will refer to this frit from now on in the recipes for cristallino, cristallo, and common glass. This way you will have cristallo quite subtle and beautiful.[1]

The above excerpt is the full extent of Neri's discussion on lime in glassmaking. An interesting point here is that he does not say why lime is so necessary. [2] He must have known that adding too much lime will cause glass to become cloudy, the exact opposite effect that he is after. What is not so clear is if Neri (or anyone else) understood that too little lime allows glass to dissolve slowly when exposed to water. 

One of the great enduring mysteries in the history of glassmaking is the question of exactly when it was understood that lime was so important. The subject became a matter of deliberate chemical investigation in the eighteenth century, but the use of lime extends much earlier. Neri's ambiguous endorsement is the first mention in print, but even among much earlier manuscripts, its role is unclear. In the first century, Roman author Pliny made a cryptic reference to adding seashells to the glass melt, but again, without further explanation. [3] Analysis of ancient glass often shows a healthy lime content, but the ingredient is never mentioned in most surviving early recipes. Of course, it may be that  lime is present in many ancient glass artifacts precisely because those artifacts are the ones that have survived without dissolving.

Some have speculated that calcium could have been introduced inadvertently as seashell fragments when sand was crushed into powder for glassmaking. This hypothesis is certainly possible, but it seems suspect considering just how much seashell would be required and how fussy the glassmakers were in obtaining pure white sand from particular locations. However, a distinction must be made between knowing that sand from a particular location makes good glass, and knowing what is in that sand. 

Perhaps the most famous such site for good glassmaking sand is the "Belus" [Na'aman] River outlet in what is now northern Israel. This is where the story of the discovery of glass takes place, as told by Pliny and other early writers. Sailors were driven here by a storm, they used natron (glassmaking salt) [4] from their cargo to hold their cooking pots up over a beach fire, and when the natron mixed with the sand in the fire, glass was formed. Or so the story tells. The nearby Phoenician cities of Tyre and Sidon are known to have hosted a thriving glass industry. The sand in this area is composed of exceptionally pure quartz, with a healthy amount of calcium from shells ground down from wave action. Together these make an ideal mix for stable glass. 

There is some evidence that experimenters such as Basil Valentine were aware that glass without lime would dissolve as early as 1520. [5] For what it is worth, I can contribute some anecdotal evidence from the twentieth century. There is a well-known product called water-glass that is essentially composed of dissolved glass without the lime. [6] My glass artist friend Emilio tells me that growing up on Murano in Venice, his mother regularly preserved fresh eggs by dipping them in water-glass, which when dry formed a hard seal over the existing shell. Presumably, she learned the technique from her own mother, but I do not know of any early references.

I would like to propose an additional explanation. Lime was a commodity that was made since ancient times, in furnaces very similar to the ones producing glass. In fact, Neri specifies the use of a “limekiln” for the production of his enamels. The archaeological remains of Tyre and Sidon show prolific use of lime based plaster and mortar in their construction practices and there are indications of lime making facilities. It seems to me that good business sense dictates that the same furnaces making glass may have also made lime. Cross contamination, and even experimentation would be a natural outcome. 

[1] Neri 1612, ch 7.
[2] As an aside, magnesia (MgO) can also serve as a stabilizer in glass.
[3] Pliny, Natural History v.36, ch. 66.192.
[4] Natron is a mix of sodium carbonates. 
[5] Basil Valentine, et al. see footnote 6 of the Wikipedia article on sodium silicate for a discussion.
[6] Sodium Silicate.

Antonio Who?

Antonio Neri's family arms, from the ceiling  of
his childhood residence in Florence.

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

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

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

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

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

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

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

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

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

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

[1] Neri 1612, Neri 2003–07. 
[2] Neri 1662.
[3] Neri 1697.
[4] Neri 2007.
[4] Zecchin 1987–89.
[5] ASF 599.
[6] Boer, Engle 2010.
[8] Grazzini 2012.
[9] Galluzzi 1982.
[10] Galileo 1890–1909.

The Duke's Mouthwash Reprise

Ferdinando de’ Medici (1549-1609),
Scipione Pulzone (1544 - 1598), Private collection.

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

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

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

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

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

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

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

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

Pope Kills Ten Days

Tomorrow is the fourth of October, imagine going to bed in the evening and the following morning you wake to find that it is not the fifth but the fifteenth of the month; ten days have gone missing. This is exactly what happened in 1582. In accordance with a proclamation by Pope Gregory XIII, the day after Thursday, 4 October, was Friday, 15 October. For the Roman Catholic world, the intervening ten days were removed from the calendar and never took place. 

The reason for this calendrical sleight of hand had to do with leap years and with Easter. Adding a day to the end of February every fourth year worked well to keep the calendar aligned with the astronomical year. But the calendar was slightly too long by a few minutes each year. Over the centuries, this creepage in was causing each successive Easter to fall a little earlier in the season. 

The seasons cycle from spring to summer to autumn to winter and back again. Think of this annual cycle as the top of a cup or drinking glass. Divide the rim into equal quadrants, one for each season. We can think of the calendar as a strip of paper. 365¼ days worth of paper wraps around the glass, but overlaps by a very small amount. In this way, each year the calendar begins a few minutes later in the season than the previous one.

The leap year system was devised in the Roman Empire and it served admirably for many centuries. However, owing to some errors in calculating early leap years and the slight error accumulating year after year over a millennium and a half 1200 years,[1] the calendar had advanced in the seasons by about ten days. Because the date of Easter is calculated astronomically, it falls within a fixed range on the rim of our glass, but the calendar kept inching forward and Easter was falling in early March, which was not acceptable to the Church. Various gradual measures were considered to remedy the situation, but in the end, it was decided to make up for the discrepancy all at once; the ten extra days accumulated over the millennium were deleted from the calendar. In addition, new rules were added for 'leap centuries'. This effectively fixed the problem.[2]

Other parts of Europe eventually adopted the changes, some sooner than others. In France, 9 December 1582 was followed by 20 December. A letter sent from Italy on November first of that year might well appear at its destination in France the last week of October, seeming to arrive before it was sent. In the Netherlands and Germany some provinces made the changes while others held out until 1700. Protestant countries did not generally adopt the new system until much later. Britain and her American colonies did not make the change until 1752 by which time the calendars were out of synchronization by a full eleven days.

When the Calendar was adjusted in Italy, Antonio Neri was six and a half years old; hardly old enough to remember the event. However, he must have experienced some of the stranger side effects in his adult life, especially when traveling. In making the journey to visit Emmanuel Ximenes, in Antwerp in 1604, if our priest stuck to the route suggested by his friend, he would have remained in Catholic territory until the very end of his journey. Once in the Low Countries, the date of the month would depend on the city. In Protestant controlled regions, like Utrecht, the date would suddenly jump backwards by ten days from nearby Catholic regions, although the days of the week would be consistent. Those crossing the English channel, from Calais France to Dover, for example, would experience a similar effect; it might be early May on one side and late April on the other. In such a crossing, one would experience the disconcerting 'Déjà vu' of living the same date range twice, once as Monday through Friday and then again as the following Thursday through Monday.

If there is a lesson here for close observers of nature, it is that daily living in the early seventeenth century emphasized the difference between the natural world and the contrivances of man. Subtle as it may seem to us today, April does not so much signify the rebirth of our gardens, as the rebirth of our gardens is what we have come to call April. The realignment of the calendar in 1582 emphasized this distinction, foreshadowing philosopher-scientist Alfred Korzybski's premise that "the map is not the territory."

[1] The Catholic Julian Calendar dates from the council of Nicaea in 325 CE, as kindly pointed out by Thony Christie (thonyc.wordpress.com), Thanks!

[2] The authoritative reference on the full extent of the changes and the events leading to them is Coyne, Hoskin, Pedersen 1983. (See the 'bibliography' link to the right.)

This post first appeared in a different form on 23 September 2013.