Monday, November 11, 2019

Guest Post

Conciatore is very pleased to present a guest post by Dr. Kate Round in which she acquaints us with the owner operator of the Audnam Glassworks in the mid 1700s.

Sarah Worral Grazebrook 1721-99
by Kate Round

After reading of Sara Vincx who in 1595, following the death of her husband, ran a successful glassmaking business in the City of Antwerp; I was reminded of a local successful businesswoman running a Glasshouse in Audnam, near Amblecote in Stourbridge, when the glass industry was flourishing in the 18th century.

Glassmaking was established in Amblecote after Lorrainer glassmakers arrived in the early 17th century. They were attracted by the best fire clay, cheap coal, sand and soda made from the burnt bracken on Pensnett Chase. De Houx built one of the early glasshouses in 1618 in Amblecote and glasshouses eventually spread over the parish making many and varied products.

Audnam Glasshouse was built in 1716 and was run by Henry Bradley. His business suffered due to the decline in the price paid for broad glass coupled with the introduction of the glass tax in 1745. He finally surrendered his business in 1747 to his landlord, Baron John Ward of Dudley.
Map of Stourbridge area canal system incl. Audnam Glassworks cone,
1774 map by Robert Whitworth.
(Click to enlarge map.)

Baron Ward immediately let the glasshouse to Michael Grazebrook I at an annual rent of £50. The association between the Dudley family and the Grazebrooks lasted 112years. Business flourished and his son Michael II (born 21st June 1723) learned the trade.


Michael II married Sarah Worral on 16th January 1753, Michael was 29yrs old and Sarah who was an only child and an heiress of Stourton in Staffordshire was aged 31. It was not uncommon for eligible businessman to seek a bride who would bring further prosperity to their allegiance. In 1640 Paul Tyzack, one of the original Huguenot glassmakers to settle in the area was sufficiently integrated into local society to see his son Paul II, marry Joyce Lyddiatt the daughter of his landlord, John Lyddiatt a scythesmith of Wollaston Hall. Joshua Henzey son of Huguenot Ananias Henzey, arrived in Stourbridge in 1618 aged just 22years, he wasted no time in marrying Joan Brettle a spinster from a substantial landowning family. Just six days after their marriage Joan gave birth to their son Ananias, baptised in Kingswinford on 5th October 1618.


The marriage between Michael Grazebrook II and Sarah Worral lasted just 15 years. Michael died in 1766 aged 42years. They had two sons, Thomas Worral Grazebrook (11/08/1756) and Michael Grazebrook III (7/03/1758). In Michael II’s will he was described as a master glassmaker and desired that trade be carried on by his widow Sarah and that stock in trade, book debts, personal estate and effects be equally divided between his only two sons, Thomas and Michael III aged 10years and 8years at the time of their fathers death.

In 1760 Audnam Flint Glasshouse was listed as manufacturing Smooth Enamel Glass, Best and Ordinary Flint Glass and Phials. Sarah Grazebrook continued to manage her late husband’s glassmaking business for many years and although both of her sons were involved, they also developed other interests in coal and ironmaking.

The glasshouse at Audnam was shown on local maps when the land around it was enclosed in 1777 and the occupier was listed as Mrs Sarah Grazebrook. She was also recorded as running Dob Hill Glasshouse owned by Robert Honeybourne. Benjamin Richardson who we consider to be the patriarch of Stourbridge glass, wrote in his notebook in 1886 that Grazebrooks needed Dob Hill Glassworks to make bottles; worked by Madame Grazebrook they used to take the material from the glasshouse at Audnam to Dob Hill Glassworks, and vice-versa. It was reported that the glasshouse at Dob Hill ‘fell-down’ sometime around 1800 and a new canal-side glasshouse was built as a replacement.

In 1783 Sarah was listed as a Glass manufacturer in a local directory and in that year also she took out a further 21-year lease from the landlord Lord Dudley. Her lease was in the sum of £52 per annum with maintenance and repairs to be undertaken by the lessee at her own cost. Sarah also took out an insurance policy in both her and her sons names on 5 May 1783. In 1793 a local directory stated that about ten glasshouses in the district had an output so great that they each paid £20,000 per annum in duty (equivalent to £2.8m today). T&M Grazebrook was one of those listed.

Michael III married in 1785 and moved to the family home Audnam House attached to the glassworks. After his marriage both Michael and his brother Thomas took over the running of the business from their mother Sarah. Their business continued to prosper in glass, coal and as ironmasters; the eight-pot glassmaking furnace traded as T & M Grazebrook, yet in 1795 it was Sarah who paid the £53 rent to Lord Dudley. Their mother remained the head of the firm until she died in 1799 aged 78y. Her will divided her estate between her two sons Thomas and Michael III.

For nineteen years, between the death of her husband in 1766 and when her sons were registered as the business owners in 1785, Sarah maintained the business. She was solely responsible for the day to day running of the eight-pot Audnam furnace and a bottle making furnace at Dob Hill. She managed the workforce, maintained healthy order books, purchased raw materials and supplied quality products; thus ensuring a flourishing business to pass on to her sons. Tradition tells that as an old lady Sarah would sit in her bedroom window with an hourglass to time her workmen’s shifts.

Like Sara Vincx in Antwerp in 1595, running successful glassmaking businesses in a male dominated environment must have bought many challenges that went unrecorded. Did Sara marry Filippo Gridolfi, one of her foremen of the furnace, to validate her position. Did both formidable ladies contribute also to product design, were they hands-on with blowing irons despite the taboo of women working glass? Who knows! some things perhaps were best left unsaid?


References:
Buckley, Francis; Old English Glasshouses, Society of Glass Technology 2006
Ellis, Jason; Glassmakers of Stourbridge and Dudley 1612-2002, Xlibris Corporation, 2002
Guttery, D R; From Broad Glass to Cut Crystal, Leonard Hill Ltd, London 1956
Engle, Paul; Sara Vincx, Glass MakerConciatore Blog 2013



Dr Kate Round is an outreach presenter and tour guide for Dudley Museum Service, based at the iconic Red House Glass Cone in Wordsley; the home of Stuart Crystal.

In her previous life, she was a research chemist and lecturer so understand the chemistry of glass having worked on the synthesis of ‘zeolites’ (silica-based materials) with her work published in International Journals. "I have always lived in the Black Country and have a strong industrial family heritage; I am also proud to have served my community as a local Magistrate for the past nineteen years. In the glass industry, my areas of interest include the historical development of the industry in the Stourbridge district, how the geology and geography impacted on the wealth and sociology of the area, driven by the rivalry of our Glass Dynasties."


Dr Kate Round JP, PhD, MRSC CChem, BSc(Hons)

Twitter: @RoundKate

Friday, November 8, 2019

Mrs Johnston, 18th Century Fancy 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.

Wednesday, November 6, 2019

Arminia Vivarini

Nef Ewer, Late 16th century, Murano Italy.
Courtesy Milwaukee Art Museum
On the afternoon of Friday, 22 March 1521, The Venetian Senate - then called the ‘Pregadi’ - reconvened after lunch. Senator Marino Sanuto (the Younger) recorded in his now famous diary that among the afternoon business was the granting of a ten year exclusive license to Arminia, the daughter of painter ‘Alvise da Muran’ (Luigi Vivarini). She was granted this privilege to produce the ornamental glass galley ships she had recently devised. [1,2] Once called 'Navicella' (little ships) these ewers, probably most used to serve wine, are now known as ‘nefs’. A pour spout was situated at the ship's bow, and often a handle astern. These objects soon became iconic symbols of the island-nation’s long dominance in trade, and regularly appeared on sideboards and elaborate dinner table settings, not only in the lagoon, but in Florence, Rome and far beyond.


In their Objects of Virtue: Art in Renaissance Italy, Syson and Thornton write,
“It was not only the use of coloured canes in complex patterns embedded into clear glass that typified Venetian glass from the 1520s, but also the manipulation of cristallo into ever more fantastic forms. Novelties were first displayed at the Ascension Day Fair, which, like visits to the glasshouses in Murano itself, was firmly on the tourist map by about 1500. The Venetian diarist Marino Sanuto mentions the work displayed at three booths at the fair in 1525, those of Barovier, Serena and Ballarin workshops ‘among other things, a galley and a very beautiful ship were to be seen.’”
Syson and Thornton continue, “Leandro Alberti singled out just this kind of glass in his famous description of the marvels of Murano in his Description of All Italy of 1550: ‘I saw there (among other things made of glass) a scaled-down model of a galley, one braccia long and with all its rigging and equipment, so perfectly in scale that it seemed impossible to model such things accurately in such a medium.” [3]


Scholar and science investigator, Georgius Agricola, described a vessel in the form of a ship in his De re metallica published in Basel in 1556,
“The glass-makers make diverse things, such as goblets, cups [...] and ships, all of which excellent and wonderful works I have seen when I spent two whole years in Venice some time ago. Especially at the time of the Feast of the Ascension they were on sale at M[u]rano, where are located the most celebrated glass-works. These I saw on other occasions, and when, for a certain reason, I visited Andrea Naugerio in his house which he had there, and conversed with him and Francisco Asulano.” [4]


Arminia Vivarini’s father was a painter of some renown, but her family is also among the earliest recorded glassmakers on Murano. Her third-great grandfather, named Vivarino, arrived from Padua, just ahead of the plague in 1346. [5] The family seems to have been involved in the craft on the island from then on. She clearly had access to a furnace, perhaps one owned by an uncle or a cousin. In any event, she exemplified the qualities of the very best glass artisans throughout history: a clear design sense coupled with technical expertise and the opportunity to put them both into practice.


Her very existence also forces us to more closely examine the well worn narrative that hot-shops were exclusively male domains, from which women were strictly excluded. In such a highly competitive arena, it is perfectly reasonable that a family would promote its best talent, regardless of gender. In many ways, we owe homage to Vivarini for her success with this style of novelty glass object; it started the genre that continues in popularity today, five centuries later, with works of art prized by collectors and in museums around the world. [6]


[1] Arminia  (Armenia, Ermonia) Vivarini (1490-1569). See Luigi Zecchin: Vetro e Vetrai di Murano, 3 vols. (Venezia: Arsenale, 1987-9) v.3, p. 194.
[2] Marino Sanudo: I diarii di Marino Sanuto (1466-1536)  v.30. Eds., F. Stefani, G. Berchet, N. Barozzi (Venezia: Fratelli Visentini, 1891) col. 45. Also see Zecchin 1987-9, v.2, p.276.
[3] Luke Syson, Dora Thornton: Objects of Virtue: Art in Renaissance Italy (Los Angeles: J. Paul Getty Museum, 2001), p. 197.
[4]  Georgius Agricola (Georg Bauer): De Re Metallica: Tr. from the 1st Latin Ed. of 1556… trns: Herbert Hoover, Lou Henry Hoover. (Princeton: Mining Magazine, 1912), p. 592 (Book XII.)
[5] op. Cit. Zecchin 1987-9, v.3, p194-5.
[6] Thanks to Sophie Small‏ @sophieesmall for inspiring the subject of this post.

Monday, November 4, 2019

Thomas Edison's Lady Glassblowers

Fig. 1. 
Sealing the Glass Socket and
Carbon Filament into the Flask of an Incandescent Lamp.
"We will next turn to the glass-blowing department, where
hundreds of girls are employed in all the delicate and skillful 
manipulations involved in the glasswork of these lamps"
-Henry Morton, Scribner's Magazine, Vol. 6, 1889
On a cold Monday afternoon in December of 1888, Thomas Edison, his wife Mina and their children arrived in Akron, Ohio, on the 12:17 train. They had traveled from their estate ‘Glenmont’ in West Orange, New Jersey, to visit Mina’s parents for the holidays. That same evening, after dinner, Edison and his father-in-law, Lewis Miller, donned winter coats and walked to a nearby station of the Akron Electric Light Co. where they inspected one of Edison’s dynamo generators that had recently been installed. The dynamo was wired by dedicated copper lines to ‘Oak Place’, Miller’s residence. Upon returning to the house, the family assembled on the third floor, along with a newspaper reporter, where a “mammoth Christmas tree” stood. That year, the tree was adorned with ornaments, tinsel, and also a special addition: forty incandescent lamps that, with a flick of a switch, blazed to life.[1] There is every chance that each of those forty lamps was crafted by female hands at Edison’s Harrison, New Jersey, factory.


Early on, Edison decided on a female crew of flamework glass artisans to perform the delicate manipulations of assembling and finishing the incandescent lamp bulbs, (fig. 1). These specialists crafted the glass parts of the lamps in a complex series of steps. The ‘stem’ makers formed a glass seal around the electrical wires that held the delicate filament in place. The ‘tubulators’ put a small hole in the top of the bulb and attached the glass tubing used to pump the air out of the bulb. Mating the stem to the bulb in an air-tight seal without cracking or damaging either was an art unto itself. All the while, workers needed to adapt on-the-fly to continual changes in materials, procedures and tools as the bulbs evolved and improved. What is known, is that in the early days,  production took place at the laboratory in Menlo Park. As demand for the lamps started to explode, a “shed” for the glass work was built and then expanded. Because of the rural location of the laboratory, there was a continual problem of recruiting qualified workers. Around 1880, Edison turned to the employment of school-aged girls and boys to fill the labor shortage. Here he got a first hand look at what they were capable of. The use of women and girls for this glass work was a tradition that continued for nearly five decades, through the transition into General Electric Co., right up until the work was fully automated.


It was a year earlier, in the spring of 1879 that Edison first made the announcement that he was ready to begin producing electric lamps. Newspapers at the time gave great credit to a German glassblower working for Edison, for bringing the inventor’s research to fruition. This was Ludwig Boehm. He previously worked for Heinrich Geissler in Bonn, Germany, producing electrical discharge tubes and vacuum pumps.[2]  Boehm possessed the glassblowing skills to quickly whip out one test lamp after another, but he also knew how to make the coveted vacuum pumps invented by Geissler. These were the leading edge of vacuum pump technology, far faster and more efficient at evacuating the air out of the lamps than other methods of the time. Edison’s achievement would have been impossible without Geissler’s work and it was Ludwig Boehm, the glassblower, who was the conduit.

By 1882, a new ‘Lamp Works’ factory was ready in Harrison, near metropolitan Newark. It had more floor space than they could possibly ever use, or so they thought. By 1889, Henry Morton, the president of Stevens Institute of technology wrote, “Hundreds of girls are employed in all the delicate and skillful manipulations involved in the glasswork of these lamps.”[3]


Fig. 2.
Laboratory notebook entry
signed solely by Mina Edison.
Edison kept a series of laboratory notebooks documenting experiments and potential solutions to problems, and for the lamps there were many problems. The entries are often signed by Edison himself or his assistants. It is interesting to note that for a period, his wife Mina co-signed some of Edison’s entries and several pages appear in her name alone. This shows her active participation at some level in events of the laboratory.[4] Fig. 2 shows an example of a page signed by Mina Edison, Dated 23 March 1886 with three diagrams of lamps. The top diagram is accompanied by text reading “Make lamps of all kinds of glass and list conductivity.” The next diagram shows a bulb with a special electrode off to the side. The text reads “polished silver. Also one of polished hard rubber.” The third diagram shows a lamp with two filaments and appears to read “copper filament to take out curr[ent] 10-” While the intent of these experimental setups may be lost, what is clear is that she possessed a working understanding of how the lamps functioned and she was proficient at circuit diagrams. Whether she influenced the decision to use female glass workers is an open question.


To become one of Edison’s glass technicians meant steady work in a booming industry, it also meant a first-hand introduction to divisive labor problems common to factories at the end of the 19th century. In the summer of 1889, the general manager of the lamp works took a trip to Europe and, based on British glass blowing practices, he ordered his superintendent in Harrison to immediately cut pay and institute a list of new work rules. The superintendent procrastinated, knowing a disaster in the making when he saw one. Upon the manager’s return in October, the superintendent was fired and the new rules and wages were posted. “The workmen immediately commenced to walk out, and it is likely that the entire force of two hundred will strike” wrote one reporter.[5] Four weeks later, the papers announced that “The girls employed in Edison’s lamp works at Harrison, N J, will go on strike today because of a reduction in wages.”[6] Four years later, an unrelated incident at the lampworks made the papers. It illustrates that even with a good work record and no problems with management, simply getting in through the front door unscathed was not a given. “There was a small riot at the Edison Lamp Works in Harrison, this morning, between several hundred men who were waiting about the gates of the establishment for work. Some objected to the presence of a number of Polish Jews and a free fight ensued, which resulted in a number being badly bruised. The police dispersed the crowd.”[7]


Fig. 3.
Wanted ad for Edison’s Harrison Lampworks factory.
The Boston Globe (Boston Massachusetts)
22 June 1894, Fri., p. 9.
Through it all, the business continued to expand by leaps and bounds. A continual stream of “wanted” advertisements ran in papers as far away as Boston (Fig. 3.) In 1896, Harper’s Magazine reported that  Edison’s lamp factory at Harrison employed “several hundred girls and men” turning out over six-million lamps per year.[8] Even with long hours and partial automation, the line would require at least a couple-hundred glass workers for the delicate hand-work necessary in order to produce what amounted to a new lamp finished every two seconds on the clock.[9]


In the early 1900s the processes for making the lamps was further automated, with women still running much of the equipment. By 1903 a single worker could turn out 600 completed bulbs per day.[10]  By 1912 the Harrison plant employed a total of 4000 workers. In 1918 the women glass workers at the plant met to discuss forming their own union in order to institute an apprentice system to ensure the trade remained healthy.[11] Ultimately the entire lamp factory was closed in 1929 and the work was distributed to more modern and fully automated facilities around the country.[12]


Fig. 4.
Finishing work by women on tungsten lamps, c.1927.
(Shortly before the manufacture of lamp bulbs was fully automated)
Notice the striking similarities to fig. 1. above, from
the same facility, 40 years earlier.
The individual women and girls who worked for the electric lamp factory in Harrison can be traced to some extent through census records. A survey of the 1900 US census found over a hundred female respondents listing the Edison Lamp Works as their place of employment [13] The oldest was Elizabeth Stultz aged 45, the youngest Tillie Glinik just 13. There were a number of sisters there working glass side-by-side. Mary and Carrie Wright were 26 and 16 respectively, while Barbara, Christina and Annie Etzel were 19, 18 and 17.[14]


There is also evidence that the use of female glassworkers for Edison carried overseas to his British lamp making operation. As an 18-year-old, Florence Small who lived in a suburb north of London, worked making glass ‘stems’ for the Edison and Swan Electric Light Company (Royal Ediswan). In 1911, she worked at their Ponders End facility in her hometown of Enfield. She thought enough of the experience to include that detail in her will, fifty years later.[15]

Those forty lamps on the Miller’s Christmas tree in 1888, along with millions of other lamps were created by the skilled female flameworkers of the Edison and later General Electric lamp works in Harrison. It is quite a legacy that from the time of the introduction of electric lamps in 1879, all the way to the invention of television in 1927, the delicate glasswork of the electric lighting industry was firmly entrusted to the competent hands of women.


[1] “A Talk With Edison”, The Summit County Beacon (Akron, Ohio), 2 Jan 1889, Wed, Page 7
[2] “A Very Skillful Glass-Blower” Chicago Tribune (Chicago, Illinois), 4 January 1880, Sun, p. 10. In US Census records and laboratory notebooks Boehm spells his own name “Ludwig K Böhm”. In later life, he reinvented himself as a patent attorney in New York.
[3] Henry Jackson Morton, “Electricity in Lighting” Scribner’s Magazine 1889 vol. VI, pp. 19-23 [compiled, pp. 176-200], (Charles Scribner’s Sons: New York) p. 192.
[4] 03/18/1886 Edison, Thomas Alva -- Technical Notes and Drawings (Edison, Mina Miller (Mrs Thomas A.)) Incandescent lamp [N314] Notebook Series -- Fort Myers Notebooks: N-86-03-18 (1886) [N314003; TAEM 42:815] Courtesy of Thomas Edison National Historical Park.
[5] The Nebraska State Journal (Lincoln, Nebraska), 12 October 1889, Sat. p. 4.
[6] The Brooklyn Daily Eagle (Brooklyn, New York), 11 November 1889, Mon. p. 4.
[7] “Edison Lamp Works Riot.” Reading Times (Reading, Pennsylvania), 5 Dec. 1893, Tue. p. 4.
[8] R. R. (Richard Rodgers) Bowker “Electricity, a Great American Industry”, Harper’s Magazine, Oct 1896, vol. 32, p. 710.
[9] In 1892 Edison began to automate the process of forming the outer bulbs, ultimately farming the work out to Corning Glassworks.
[10] John W. Howell And Henry Schroeder, “History of the Incandescent Lamp” (The Maqua Company: Schenectady, New York ,1927), pp. 165-172.
[11] “Have Mass Meeting of Lamp Works Employes” (sic.), The Fort Wayne Sentinel (Fort Wayne, Indiana) 31 December 1918, p. 3.
[12] In 1932 the Harrison factory was re-purposed for the Radiophone Corporation of America. RCA, which produced electronic tubes until 1976. The site was ultimately leveled and is now home to a shopping mall.
[13] Combinations of search terms targeted females working at the Harrison, New Jersey Edison/General Electric Lamp Works. Women found working there, but not listing a specific profession could have worked non glass blowing jobs. Conversely, many who were glass workers at the plant left the census field for 'employment' blank, or were not asked by the census taker and therefore not found in the search.
[14] No candidates could be found in the 1880 US census, and the 1890 census was largely destroyed in a fire at the Commerce Dept. in 1921.
[15] Probate details for Florence Small provided by https://www.terrys.org.uk/charts/c/crack301.htm


Fig. 1: Sealing the Glass Socket and Carbon Filament into the Flask of an Incandescent Lamp. 1889
Fig. 2: Laboratory notebook entry signed solely by Mina Edison.
Fig. 3: Wanted ad for Edison’s Harrison Lampworks factory. The Boston Globe (Boston Massachusetts) 22 June 1894, Fri., p. 9.
Fig. 4: Finishing work on tungsten lamps, c.1927.

Friday, November 1, 2019

Sara Vincx, Glass Maker

Still life with façon de Venise wineglass,
Alexander Adriaenssen (1587-1661)
Antwerp.
In the 1590s, after the death of her husband, Sara Vincx ran a successful glassmaking business in the city of Antwerp. In the midst of a major war, she presided over a furnace where craftsmen from Murano, Italy, made fine cristallo glassware for the elite families in Flanders. Vinx is the first documented female owner of a glass furnace anywhere.

The Dutch Eighty Years' War for independence from Spain was heating up in Flanders; towns were being pillaged and burned to the ground throughout the Low Countries. Even so, Vincx ably managed a crew of expert glass artists and brought her company's wares to market. When competitors tried to duplicate her products, she successfully defended her shop in court. Later, she remarried to Filippo Gridolfi, one of her foremen at the furnace. The two went on to open a show-room on the Meir, the most prestigious sales district of the city. They also welcomed glassmaker Antonio Neri to work at their facility. Neri was living in the city on an extended seven year visit to his friend and fellow alchemical experimenter Emmanuel Ximenes. 

The seven years that Antonio Neri spent in Antwerp were arguably the most formative for his knowledge of glassmaking. While his first exposure to the art was in Italy, a large portion of the skills and recipes exhibited in his book, L'Arte Vetraria, trace to his activities in the Low Countries. Neri writes "This will make a beautiful aquamarine so nice and marvelous, that you will be astonished, as I have done many times in Flanders in the city of Antwerp to the marvel of all those that saw it." On tinting rock crystal: "In Antwerp, I made quite a bit of this, some ranged in tint from an opal color that looked very beautiful, to a girasol, similarly nice." On equipment: "In Antwerp, I built a furnace that held twenty glass-pots of various colors and when fired for twenty-four hours everything fused and purified." He also speaks of chalcedony glass, paste gems  and ultramarine paint all crafted in Antwerp.

Neri was apparently on good terms with Vincx and Gridolfi, perhaps he was introduced through Ximenes, one of the wealthiest men in the city. In his book Neri describes Gridolfi as "a most courteous gentleman." Vincx and Gridolfi possessed exclusive rights in the region to produce cristallo glass in the Venetian style (façon de Venice) a type of glass that Neri was already quite familiar with from his time making glass in Florence. The license, or patent as it was called, passed down from previous owners, was quite a valuable part of the operation. Employed in their shop was a steady stream of craftsmen from Murano. They made the finest glassware for the upper classes of Antwerp and surrounding areas. Because these craftsmen were bringing the secret techniques with them, they worked outside of the guild system, which would have otherwise required them to share their techniques with other artisans. Through special arrangements with the local authorities, the Venetians were exempt from joining. 


Sara Vincx (or Vincks) was the widow of the former owner, Ambrogio de Mongarda. Gridolfi had previously worked in the shop under Mongarda, who had been in the business for twenty years. Vincx was pressed into service by unhappy circumstances. In 1594, Ambrogio returned alone to Venice to recuperate from gout, but by the following year he was dead, leaving Sara to both run the glass shop and care for at least eight young children. Sara Vincx carries a distinction as the first documented female owner of a glass furnace anywhere. She took an active role in the business as attested by lawsuits she filed, and won, against rival shops that violated her patent. Records show she also expanded the furnace and hired two new artisans to increase production.

Despite the war and the Spanish blockade of the Scheldt River, which shut down trade by sea for a number of years in Antwerp, the glass furnace there thrived and reached its zenith under Vincx and Gridolfi. Soon after their marriage, seventeen employees were counted working at the shop. They established their own retail presence on the Meir, selling high-end cristallo within steps of the Ximenes palace. Their glass operation enjoyed top-rung status, and no doubt, Antonio Neri's involvement must have bolstered the reputation of the firm even further.

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

Wednesday, October 30, 2019

Witch's Brew of Glass

Glass pumpkin evocative of chalcedony glass
Courtesy of  Smithsonian Museum store.
In honor of Halloween, we will take a detailed look at chalcedony glass; this is one of, if not the most colorful types of glass ever made. In the seventeenth century, it was extremely dangerous for glassmakers and artists, containing a veritable “witch’s brew” of toxic materials. In his 1612 book, L’Arte Vetraria, glassmaker Antonio Neri presents three recipes of which he is clearly very proud. Each of the three is attended by a complex list of ingredients. He describes the end result this way:
It will be adorned with so many graceful and beautiful areas of undulations, and enhanced with the play of diverse, lively, flaming colors, that truly it will seem nature cannot attain so great a height or grand a prize. [1]
In the same passage, Neri explains the importance of purifying each ingredient and eliminating all contamination. In so doing, he provides a fascinating insight into the thinking of an alchemist. He writes:
There is no doubt that in this art, when the ingredients are well prepared, they permeate the glass with dazzling lively colors. Impurities will ordinarily impede the entry of the tinctures into the glass, and prevent their intimate unification. However, when you open the colors of the metals well, and separate them from their impurities and sediment, their beauty will always by far surpass those that are common and ordinarily made in the furnace. [2]
To Neri’s mind, the metals used as pigments must undergo a process of “opening.” Once this was done, each metal’s characteristic color or “tincture” was free to permeate the glass, provided it was free of impurities. Today we might say that by reducing each metal into an extremely fine powder, the individual atoms more easily disperse in the glass. Neri’s “opening” process usually involved dissolving a pure metal in an acid and then slowly evaporating the liquid, resulting in a fine powder. Most color arises because, once in the glass,  the metal atoms block some parts of the spectrum, but not others. The result is that each metal gives rise to its own hue and only because it is dispersed in the oxygen rich environment of the glass matrix. 

 The striking point here is how the alchemist’s model was a perfectly adequate description for the times, in the same way that the atomic model works for us. Unfortunately, there was less awareness of the negative health consequences in some of these preparations. The evaporation of powerful acids could (and can) certainly cause acute respiratory and tissue irritation. However there were far more insidious dangers lurking in Neri’s chalcedony recipes.
Ribbed vessel, chalcedony glass, 17th century, 
 Museo del Monastero di Santa Giulia, Brescia.

In his first prescription, he dissolves silver, mercury, cobalt, manganese, copper and iron. [3] Some of these have been prepared with sulfur which also ends up in the mix. He evaporates it to a powder and adds it to well seasoned, good quality clear glass along with pulverized chimney soot. He notes “When you stir [the molten glass] thoroughly it gives off a definite blue smoke.” Specifically hazardous in this recipe is the formation of mercury fumes, which are extremely toxic to breathe. 

He advises that in the furnace the glass appears “as red as fire,” but that “master craftsman always pinches off the glass for the job with nippers, and reheats it, in order to make waves, undulations and interplays of the most beautiful colors.” The reheating process is known to modern glassmakers as “striking,” a maneuver that brings out surprising color in some glass formulations. He suggests that this chalcedony can be used to form drinking glasses to more shapely cups, saltshakers, flower vases and similar vessels.

In his second and more sophisticated preparation Neri dissolves the materials in groups, in six separate flasks, only then combining them. He also adds new materials: lead, zinc, “blue painters enamel,” antimony and red varnish. The final recipe for chalcedony introduces new purification procedures and increases the number of separate flasks to nine. Additional ingredients include metal sulfides, ultramarine, tin, arsenic (read: death's calling card) and crimson paint. 

It is tempting to dismiss a few of these ingredients, like red varnish, or pulverized chimney soot; organic materials that would readily decompose in the heat of the furnace. However, Neri is known to have been a careful experimenter and these additions may well have had an effect on the melt, even if not in terms of color. Of the third recipe, which Neri developed in Antwerp, he wrote: 
Many Portuguese gentlemen in the practice of appraising jewels said that nature could do no better. This was the most beautiful chalcedony that I have ever made in my life. While it may be quite laborious and take a long time to produce, the result is fit for a king. I presented His Excellency, the Prince of Orange, with two vessels of this chalcedony, which delighted him greatly. [4]

[1] Neri 1612, p. 34.
[2] Ibid.
[3] Manganese and cobalt were unknown as distinct metals, but were used in their oxide forms, mined as minerals.
[4] Neri 1612, p. 48. The prince of orange was Philip William.
* This post first appeared here on 31 Oct 2014.

Monday, October 28, 2019

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.